1	/* Target hook definitions.
2	Copyright (C) 2001-2024 Free Software Foundation, Inc.
3
4	This program is free software; you can redistribute it and/or modify it
5	under the terms of the GNU General Public License as published by the
6	Free Software Foundation; either version 3, or (at your option) any
7	later version.
8
9	This program is distributed in the hope that it will be useful,
10	but WITHOUT ANY WARRANTY; without even the implied warranty of
11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12	GNU General Public License for more details.
13
14	You should have received a copy of the GNU General Public License
15	along with this program; see the file COPYING3. If not see
16	<http://www.gnu.org/licenses/>.
17
18	In other words, you are welcome to use, share and improve this program.
19	You are forbidden to forbid anyone else to use, share and improve
20	what you give them. Help stamp out software-hoarding! */
21
22	/* See target-hooks-macros.h for details of macros that should be
23	provided by the including file, and how to use them here. */
24	#include "target-hooks-macros.h"
25
26	#undef HOOK_TYPE
27	#define HOOK_TYPE "Target Hook"
28
29	HOOK_VECTOR (TARGET_INITIALIZER, gcc_target)
30
31	/* Functions that output assembler for the target. */
32	#define HOOK_PREFIX "TARGET_ASM_"
33	HOOK_VECTOR (TARGET_ASM_OUT, asm_out)
34
35	/* Opening and closing parentheses for asm expression grouping. */
36	DEFHOOKPOD
37	(open_paren,
38	"These target hooks are C string constants, describing the syntax in the\n\
39	assembler for grouping arithmetic expressions. If not overridden, they\n\
40	default to normal parentheses, which is correct for most assemblers.",
41	const char *, "(")
42	DEFHOOKPODX (close_paren, const char *, ")")
43
44	/* Assembler instructions for creating various kinds of integer object. */
45	DEFHOOKPOD
46	(byte_op,
47	"@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_HI_OP\n\
48	@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_PSI_OP\n\
49	@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_SI_OP\n\
50	@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_PDI_OP\n\
51	@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP\n\
52	@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_PTI_OP\n\
53	@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP\n\
54	@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP\n\
55	@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_PSI_OP\n\
56	@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP\n\
57	@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_PDI_OP\n\
58	@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP\n\
59	@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_PTI_OP\n\
60	@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP\n\
61	These hooks specify assembly directives for creating certain kinds\n\
62	of integer object. The @code{TARGET_ASM_BYTE_OP} directive creates a\n\
63	byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an\n\
64	aligned two-byte object, and so on. Any of the hooks may be\n\
65	@code{NULL}, indicating that no suitable directive is available.\n\
66	\n\
67	The compiler will print these strings at the start of a new line,\n\
68	followed immediately by the object's initial value. In most cases,\n\
69	the string should contain a tab, a pseudo-op, and then another tab.",
70	const char *, "\t.byte\t")
71	DEFHOOKPOD (aligned_op, "*", struct asm_int_op, TARGET_ASM_ALIGNED_INT_OP)
72	DEFHOOKPOD (unaligned_op, "*", struct asm_int_op, TARGET_ASM_UNALIGNED_INT_OP)
73
74	/* Try to output the assembler code for an integer object whose
75	value is given by X. SIZE is the size of the object in bytes and
76	ALIGNED_P indicates whether it is aligned. Return true if
77	successful. Only handles cases for which BYTE_OP, ALIGNED_OP
78	and UNALIGNED_OP are NULL. */
79	DEFHOOK
80	(integer,
81	"The @code{assemble_integer} function uses this hook to output an\n\
82	integer object. @var{x} is the object's value, @var{size} is its size\n\
83	in bytes and @var{aligned_p} indicates whether it is aligned. The\n\
84	function should return @code{true} if it was able to output the\n\
85	object. If it returns false, @code{assemble_integer} will try to\n\
86	split the object into smaller parts.\n\
87	\n\
88	The default implementation of this hook will use the\n\
89	@code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}\n\
90	when the relevant string is @code{NULL}.",
91	/* Only handles cases for which BYTE_OP, ALIGNED_OP and UNALIGNED_OP are
92	NULL. */
93	bool, (rtx x, unsigned int size, int aligned_p),
94	default_assemble_integer)
95
96	/* Assembly strings required after the .cfi_startproc label. */
97	DEFHOOK
98	(post_cfi_startproc,
99	"This target hook is used to emit assembly strings required by the target\n\
100	after the .cfi_startproc directive. The first argument is the file stream to\n\
101	write the strings to and the second argument is the function\'s declaration. The\n\
102	expected use is to add more .cfi_* directives.\n\
103	\n\
104	The default is to not output any assembly strings.",
105	void, (FILE *, tree),
106	hook_void_FILEptr_tree)
107
108	/* Notify the backend that we have completed emitting the data for a
109	decl. */
110	DEFHOOK
111	(decl_end,
112	"Define this hook if the target assembler requires a special marker to\n\
113	terminate an initialized variable declaration.",
114	void, (void),
115	hook_void_void)
116
117	/* Output code that will globalize a label. */
118	DEFHOOK
119	(globalize_label,
120	"This target hook is a function to output to the stdio stream\n\
121	@var{stream} some commands that will make the label @var{name} global;\n\
122	that is, available for reference from other files.\n\
123	\n\
124	The default implementation relies on a proper definition of\n\
125	@code{GLOBAL_ASM_OP}.",
126	void, (FILE *stream, const char *name),
127	default_globalize_label)
128
129	/* Output code that will globalize a declaration. */
130	DEFHOOK
131	(globalize_decl_name,
132	"This target hook is a function to output to the stdio stream\n\
133	@var{stream} some commands that will make the name associated with @var{decl}\n\
134	global; that is, available for reference from other files.\n\
135	\n\
136	The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
137	void, (FILE *stream, tree decl), default_globalize_decl_name)
138
139	/* Output code that will declare an external variable. */
140	DEFHOOK
141	(assemble_undefined_decl,
142	"This target hook is a function to output to the stdio stream\n\
143	@var{stream} some commands that will declare the name associated with\n\
144	@var{decl} which is not defined in the current translation unit. Most\n\
145	assemblers do not require anything to be output in this case.",
146	void, (FILE *stream, const char *name, const_tree decl),
147	hook_void_FILEptr_constcharptr_const_tree)
148
149	/* Output code that will emit a label for unwind info, if this
150	target requires such labels. Second argument is the decl the
151	unwind info is associated with, third is a boolean: true if
152	this is for exception handling, fourth is a boolean: true if
153	this is only a placeholder for an omitted FDE. */
154	DEFHOOK
155	(emit_unwind_label,
156	"This target hook emits a label at the beginning of each FDE@. It\n\
157	should be defined on targets where FDEs need special labels, and it\n\
158	should write the appropriate label, for the FDE associated with the\n\
159	function declaration @var{decl}, to the stdio stream @var{stream}.\n\
160	The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
161	exception table. The fourth argument, @var{empty}, is a boolean:\n\
162	true if this is a placeholder label for an omitted FDE@.\n\
163	\n\
164	The default is that FDEs are not given nonlocal labels.",
165	void, (FILE *stream, tree decl, int for_eh, int empty),
166	default_emit_unwind_label)
167
168	/* Output code that will emit a label to divide up the exception table. */
169	DEFHOOK
170	(emit_except_table_label,
171	"This target hook emits a label at the beginning of the exception table.\n\
172	It should be defined on targets where it is desirable for the table\n\
173	to be broken up according to function.\n\
174	\n\
175	The default is that no label is emitted.",
176	void, (FILE *stream),
177	default_emit_except_table_label)
178
179	/* Emit a directive for setting the personality for the function. */
180	DEFHOOK
181	(emit_except_personality,
182	"If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\n\
183	used to emit a directive to install a personality hook into the unwind\n\
184	info. This hook should not be used if dwarf2 unwind info is used.",
185	void, (rtx personality),
186	NULL)
187
188	/* If necessary, modify personality and LSDA references to handle
189	indirection. This is used when the assembler supports CFI directives. */
190	DEFHOOK
191	(make_eh_symbol_indirect,
192	"If necessary, modify personality and LSDA references to handle indirection.\n\
193	The original symbol is in @code{origsymbol} and if @code{pubvis} is true\n\
194	the symbol is visible outside the TU.",
195	rtx, (rtx origsymbol, bool pubvis),
196	NULL)
197
198	/* Emit any directives required to unwind this instruction. */
199	DEFHOOK
200	(unwind_emit,
201	"This target hook emits assembly directives required to unwind the\n\
202	given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
203	returns @code{UI_TARGET}.",
204	void, (FILE *stream, rtx_insn *insn),
205	NULL)
206
207	DEFHOOKPOD
208	(unwind_emit_before_insn,
209	"True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\n\
210	the assembly for @var{insn} has been emitted, false if the hook should\n\
211	be called afterward.",
212	bool, true)
213
214	/* Return true if the target needs extra instructions to restore the current
215	frame address after a DW_CFA_restore_state opcode. */
216	DEFHOOK
217	(should_restore_cfa_state,
218	"For DWARF-based unwind frames, two CFI instructions provide for save and\n\
219	restore of register state. GCC maintains the current frame address (CFA)\n\
220	separately from the register bank but the unwinder in libgcc preserves this\n\
221	state along with the registers (and this is expected by the code that writes\n\
222	the unwind frames). This hook allows the target to specify that the CFA data\n\
223	is not saved/restored along with the registers by the target unwinder so that\n\
224	suitable additional instructions should be emitted to restore it.",
225	bool, (void),
226	hook_bool_void_false)
227
228	/* Generate an internal label.
229	For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL. */
230	DEFHOOK_UNDOC
231	(generate_internal_label,
232	"",
233	void, (char *buf, const char *prefix, unsigned long labelno),
234	default_generate_internal_label)
235
236	/* Output an internal label. */
237	DEFHOOK
238	(internal_label,
239	"A function to output to the stdio stream @var{stream} a label whose\n\
240	name is made from the string @var{prefix} and the number @var{labelno}.\n\
241	\n\
242	It is absolutely essential that these labels be distinct from the labels\n\
243	used for user-level functions and variables. Otherwise, certain programs\n\
244	will have name conflicts with internal labels.\n\
245	\n\
246	It is desirable to exclude internal labels from the symbol table of the\n\
247	object file. Most assemblers have a naming convention for labels that\n\
248	should be excluded; on many systems, the letter @samp{L} at the\n\
249	beginning of a label has this effect. You should find out what\n\
250	convention your system uses, and follow it.\n\
251	\n\
252	The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.",
253	void, (FILE *stream, const char *prefix, unsigned long labelno),
254	default_internal_label)
255
256	/* Output label for the constant. */
257	DEFHOOK
258	(declare_constant_name,
259	"A target hook to output to the stdio stream @var{file} any text necessary\n\
260	for declaring the name @var{name} of a constant which is being defined. This\n\
261	target hook is responsible for outputting the label definition (perhaps using\n\
262	@code{assemble_label}). The argument @var{exp} is the value of the constant,\n\
263	and @var{size} is the size of the constant in bytes. The @var{name}\n\
264	will be an internal label.\n\
265	\n\
266	The default version of this target hook, define the @var{name} in the\n\
267	usual manner as a label (by means of @code{assemble_label}).\n\
268	\n\
269	You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.",
270	void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
271	default_asm_declare_constant_name)
272
273	/* Emit a ttype table reference to a typeinfo object. */
274	DEFHOOK
275	(ttype,
276	"This hook is used to output a reference from a frame unwinding table to\n\
277	the type_info object identified by @var{sym}. It should return @code{true}\n\
278	if the reference was output. Returning @code{false} will cause the\n\
279	reference to be output using the normal Dwarf2 routines.",
280	bool, (rtx sym),
281	hook_bool_rtx_false)
282
283	/* Emit an assembler directive to set visibility for the symbol
284	associated with the tree decl. */
285	DEFHOOK
286	(assemble_visibility,
287	"This target hook is a function to output to @var{asm_out_file} some\n\
288	commands that will make the symbol(s) associated with @var{decl} have\n\
289	hidden, protected or internal visibility as specified by @var{visibility}.",
290	void, (tree decl, int visibility),
291	default_assemble_visibility)
292
293	DEFHOOK
294	(print_patchable_function_entry,
295	"Generate a patchable area at the function start, consisting of\n\
296	@var{patch_area_size} NOP instructions. If the target supports named\n\
297	sections and if @var{record_p} is true, insert a pointer to the current\n\
298	location in the table of patchable functions. The default implementation\n\
299	of the hook places the table of pointers in the special section named\n\
300	@code{__patchable_function_entries}.",
301	void, (FILE *file, unsigned HOST_WIDE_INT patch_area_size, bool record_p),
302	default_print_patchable_function_entry)
303
304	/* Output the assembler code for entry to a function. */
305	DEFHOOK
306	(function_prologue,
307	"If defined, a function that outputs the assembler code for entry to a\n\
308	function. The prologue is responsible for setting up the stack frame,\n\
309	initializing the frame pointer register, saving registers that must be\n\
310	saved, and allocating @var{size} additional bytes of storage for the\n\
311	local variables. @var{file} is a stdio stream to which the assembler\n\
312	code should be output.\n\
313	\n\
314	The label for the beginning of the function need not be output by this\n\
315	macro. That has already been done when the macro is run.\n\
316	\n\
317	@findex regs_ever_live\n\
318	To determine which registers to save, the macro can refer to the array\n\
319	@code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
320	@var{r} is used anywhere within the function. This implies the function\n\
321	prologue should save register @var{r}, provided it is not one of the\n\
322	call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
323	@code{regs_ever_live}.)\n\
324	\n\
325	On machines that have ``register windows'', the function entry code does\n\
326	not save on the stack the registers that are in the windows, even if\n\
327	they are supposed to be preserved by function calls; instead it takes\n\
328	appropriate steps to ``push'' the register stack, if any non-call-used\n\
329	registers are used in the function.\n\
330	\n\
331	@findex frame_pointer_needed\n\
332	On machines where functions may or may not have frame-pointers, the\n\
333	function entry code must vary accordingly; it must set up the frame\n\
334	pointer if one is wanted, and not otherwise. To determine whether a\n\
335	frame pointer is in wanted, the macro can refer to the variable\n\
336	@code{frame_pointer_needed}. The variable's value will be 1 at run\n\
337	time in a function that needs a frame pointer. @xref{Elimination}.\n\
338	\n\
339	The function entry code is responsible for allocating any stack space\n\
340	required for the function. This stack space consists of the regions\n\
341	listed below. In most cases, these regions are allocated in the\n\
342	order listed, with the last listed region closest to the top of the\n\
343	stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
344	the highest address if it is not defined). You can use a different order\n\
345	for a machine if doing so is more convenient or required for\n\
346	compatibility reasons. Except in cases where required by standard\n\
347	or by a debugger, there is no reason why the stack layout used by GCC\n\
348	need agree with that used by other compilers for a machine.",
349	void, (FILE *file),
350	default_function_pro_epilogue)
351
352	/* Output the assembler code for end of prologue. */
353	DEFHOOK
354	(function_end_prologue,
355	"If defined, a function that outputs assembler code at the end of a\n\
356	prologue. This should be used when the function prologue is being\n\
357	emitted as RTL, and you have some extra assembler that needs to be\n\
358	emitted. @xref{prologue instruction pattern}.",
359	void, (FILE *file),
360	no_asm_to_stream)
361
362	/* Output the assembler code for start of epilogue. */
363	DEFHOOK
364	(function_begin_epilogue,
365	"If defined, a function that outputs assembler code at the start of an\n\
366	epilogue. This should be used when the function epilogue is being\n\
367	emitted as RTL, and you have some extra assembler that needs to be\n\
368	emitted. @xref{epilogue instruction pattern}.",
369	void, (FILE *file),
370	no_asm_to_stream)
371
372	/* Output the assembler code for function exit. */
373	DEFHOOK
374	(function_epilogue,
375	"If defined, a function that outputs the assembler code for exit from a\n\
376	function. The epilogue is responsible for restoring the saved\n\
377	registers and stack pointer to their values when the function was\n\
378	called, and returning control to the caller. This macro takes the\n\
379	same argument as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
380	registers to restore are determined from @code{regs_ever_live} and\n\
381	@code{CALL_USED_REGISTERS} in the same way.\n\
382	\n\
383	On some machines, there is a single instruction that does all the work\n\
384	of returning from the function. On these machines, give that\n\
385	instruction the name @samp{return} and do not define the macro\n\
386	@code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
387	\n\
388	Do not define a pattern named @samp{return} if you want the\n\
389	@code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target\n\
390	switches to control whether return instructions or epilogues are used,\n\
391	define a @samp{return} pattern with a validity condition that tests the\n\
392	target switches appropriately. If the @samp{return} pattern's validity\n\
393	condition is false, epilogues will be used.\n\
394	\n\
395	On machines where functions may or may not have frame-pointers, the\n\
396	function exit code must vary accordingly. Sometimes the code for these\n\
397	two cases is completely different. To determine whether a frame pointer\n\
398	is wanted, the macro can refer to the variable\n\
399	@code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
400	a function that needs a frame pointer.\n\
401	\n\
402	Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
403	@code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
404	The C variable @code{current_function_is_leaf} is nonzero for such a\n\
405	function. @xref{Leaf Functions}.\n\
406	\n\
407	On some machines, some functions pop their arguments on exit while\n\
408	others leave that for the caller to do. For example, the 68020 when\n\
409	given @option{-mrtd} pops arguments in functions that take a fixed\n\
410	number of arguments.\n\
411	\n\
412	@findex pops_args\n\
413	@findex crtl->args.pops_args\n\
414	Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
415	functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
416	needs to know what was decided. The number of bytes of the current\n\
417	function's arguments that this function should pop is available in\n\
418	@code{crtl->args.pops_args}. @xref{Scalar Return}.",
419	void, (FILE *file),
420	default_function_pro_epilogue)
421
422	/* Initialize target-specific sections. */
423	DEFHOOK
424	(init_sections,
425	"Define this hook if you need to do something special to set up the\n\
426	@file{varasm.cc} sections, or if your target has some special sections\n\
427	of its own that you need to create.\n\
428	\n\
429	GCC calls this hook after processing the command line, but before writing\n\
430	any assembly code, and before calling any of the section-returning hooks\n\
431	described below.",
432	void, (void),
433	hook_void_void)
434
435	/* Tell assembler to change to section NAME with attributes FLAGS.
436	If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
437	which this section is associated. */
438	DEFHOOK
439	(named_section,
440	"Output assembly directives to switch to section @var{name}. The section\n\
441	should have attributes as specified by @var{flags}, which is a bit mask\n\
442	of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
443	is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
444	this section is associated.",
445	void, (const char *name, unsigned int flags, tree decl),
446	default_no_named_section)
447
448	/* Tell assembler what section attributes to assign this elf section
449	declaration, using their numerical value. */
450	DEFHOOK
451	(elf_flags_numeric,
452	"This hook can be used to encode ELF section flags for which no letter\n\
453	code has been defined in the assembler. It is called by\n\
454	@code{default_asm_named_section} whenever the section flags need to be\n\
455	emitted in the assembler output. If the hook returns true, then the\n\
456	numerical value for ELF section flags should be calculated from\n\
457	@var{flags} and saved in @var{*num}; the value is printed out instead of the\n\
458	normal sequence of letter codes. If the hook is not defined, or if it\n\
459	returns false, then @var{num} is ignored and the traditional letter sequence\n\
460	is emitted.",
461	bool, (unsigned int flags, unsigned int *num),
462	hook_bool_uint_uintp_false)
463
464	/* Return preferred text (sub)section for function DECL.
465	Main purpose of this function is to separate cold, normal and hot
466	functions. STARTUP is true when function is known to be used only
467	at startup (from static constructors or it is main()).
468	EXIT is true when function is known to be used only at exit
469	(from static destructors).
470	Return NULL if function should go to default text section. */
471	DEFHOOK
472	(function_section,
473	"Return preferred text (sub)section for function @var{decl}.\n\
474	Main purpose of this function is to separate cold, normal and hot\n\
475	functions. @var{startup} is true when function is known to be used only\n\
476	at startup (from static constructors or it is @code{main()}).\n\
477	@var{exit} is true when function is known to be used only at exit\n\
478	(from static destructors).\n\
479	Return NULL if function should go to default text section.",
480	section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
481	default_function_section)
482
483	/* Output the assembler code for function exit. */
484	DEFHOOK
485	(function_switched_text_sections,
486	"Used by the target to emit any assembler directives or additional\n\
487	labels needed when a function is partitioned between different\n\
488	sections. Output should be written to @var{file}. The function\n\
489	decl is available as @var{decl} and the new section is `cold' if\n\
490	@var{new_is_cold} is @code{true}.",
491	void, (FILE *file, tree decl, bool new_is_cold),
492	default_function_switched_text_sections)
493
494	/* Return a mask describing how relocations should be treated when
495	selecting sections. Bit 1 should be set if global relocations
496	should be placed in a read-write section; bit 0 should be set if
497	local relocations should be placed in a read-write section. */
498	DEFHOOK
499	(reloc_rw_mask,
500	"Return a mask describing how relocations should be treated when\n\
501	selecting sections. Bit 1 should be set if global relocations\n\
502	should be placed in a read-write section; bit 0 should be set if\n\
503	local relocations should be placed in a read-write section.\n\
504	\n\
505	The default version of this function returns 3 when @option{-fpic}\n\
506	is in effect, and 0 otherwise. The hook is typically redefined\n\
507	when the target cannot support (some kinds of) dynamic relocations\n\
508	in read-only sections even in executables.",
509	int, (void),
510	default_reloc_rw_mask)
511
512	/* Return a flag for either generating ADDR_DIF_VEC table
513	or ADDR_VEC table for jumps in case of -fPIC/-fPIE. */
514	DEFHOOK
515	(generate_pic_addr_diff_vec,
516	"Return true to generate ADDR_DIF_VEC table\n\
517	or false to generate ADDR_VEC table for jumps in case of -fPIC.\n\
518	\n\
519	The default version of this function returns true if flag_pic\n\
520	equals true and false otherwise",
521	bool, (void),
522	default_generate_pic_addr_diff_vec)
523
524	/* Return a section for EXP. It may be a DECL or a constant. RELOC
525	is nonzero if runtime relocations must be applied; bit 1 will be
526	set if the runtime relocations require non-local name resolution.
527	ALIGN is the required alignment of the data. */
528	DEFHOOK
529	(select_section,
530	"Return the section into which @var{exp} should be placed. You can\n\
531	assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
532	some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
533	requires link-time relocations. Bit 0 is set when variable contains\n\
534	local relocations only, while bit 1 is set for global relocations.\n\
535	@var{align} is the constant alignment in bits.\n\
536	\n\
537	The default version of this function takes care of putting read-only\n\
538	variables in @code{readonly_data_section}.\n\
539	\n\
540	See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
541	section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
542	default_select_section)
543
544	/* Return a section for X. MODE is X's mode and ALIGN is its
545	alignment in bits. */
546	DEFHOOK
547	(select_rtx_section,
548	"Return the section into which a constant @var{x}, of mode @var{mode},\n\
549	should be placed. You can assume that @var{x} is some kind of\n\
550	constant in RTL@. The argument @var{mode} is redundant except in the\n\
551	case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
552	in bits.\n\
553	\n\
554	The default version of this function takes care of putting symbolic\n\
555	constants in @code{flag_pic} mode in @code{data_section} and everything\n\
556	else in @code{readonly_data_section}.",
557	section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
558	default_select_rtx_section)
559
560	/* Select a unique section name for DECL. RELOC is the same as
561	for SELECT_SECTION. */
562	DEFHOOK
563	(unique_section,
564	"Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
565	and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
566	As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
567	the initial value of @var{exp} requires link-time relocations.\n\
568	\n\
569	The default version of this function appends the symbol name to the\n\
570	ELF section name that would normally be used for the symbol. For\n\
571	example, the function @code{foo} would be placed in @code{.text.foo}.\n\
572	Whatever the actual target object format, this is often good enough.",
573	void, (tree decl, int reloc),
574	default_unique_section)
575
576	/* Return the readonly data or relocated readonly data section
577	associated with function DECL. */
578	DEFHOOK
579	(function_rodata_section,
580	"Return the readonly data or reloc readonly data section associated with\n\
581	@samp{DECL_SECTION_NAME (@var{decl})}. @var{relocatable} selects the latter\n\
582	over the former.\n\
583	The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
584	the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
585	or @code{.data.rel.ro.name} if function is in @code{.text.name}, and\n\
586	the normal readonly-data or reloc readonly data section otherwise.",
587	section *, (tree decl, bool relocatable),
588	default_function_rodata_section)
589
590	/* Nonnull if the target wants to override the default ".rodata" prefix
591	for mergeable data sections. */
592	DEFHOOKPOD
593	(mergeable_rodata_prefix,
594	"Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
595	section names for mergeable constant data. Define this macro to override\n\
596	the string if a different section name should be used.",
597	const char *, ".rodata")
598
599	/* Return the section to be used for transactional memory clone tables. */
600	DEFHOOK
601	(tm_clone_table_section,
602	"Return the section that should be used for transactional memory clone\n\
603	tables.",
604	section *, (void), default_clone_table_section)
605
606	/* Output a constructor for a symbol with a given priority. */
607	DEFHOOK
608	(constructor,
609	"If defined, a function that outputs assembler code to arrange to call\n\
610	the function referenced by @var{symbol} at initialization time.\n\
611	\n\
612	Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
613	no arguments and with no return value. If the target supports initialization\n\
614	priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
615	otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
616	\n\
617	If this macro is not defined by the target, a suitable default will\n\
618	be chosen if (1) the target supports arbitrary section names, (2) the\n\
619	target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
620	is not defined.",
621	void, (rtx symbol, int priority), NULL)
622
623	/* Output a destructor for a symbol with a given priority. */
624	DEFHOOK
625	(destructor,
626	"This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
627	functions rather than initialization functions.",
628	void, (rtx symbol, int priority), NULL)
629
630	/* Output the assembler code for a thunk function. THUNK_DECL is the
631	declaration for the thunk function itself, FUNCTION is the decl for
632	the target function. DELTA is an immediate constant offset to be
633	added to THIS. If VCALL_OFFSET is nonzero, the word at
634	*(*this + vcall_offset) should be added to THIS. */
635	DEFHOOK
636	(output_mi_thunk,
637	"A function that outputs the assembler code for a thunk\n\
638	function, used to implement C++ virtual function calls with multiple\n\
639	inheritance. The thunk acts as a wrapper around a virtual function,\n\
640	adjusting the implicit object parameter before handing control off to\n\
641	the real function.\n\
642	\n\
643	First, emit code to add the integer @var{delta} to the location that\n\
644	contains the incoming first argument. Assume that this argument\n\
645	contains a pointer, and is the one used to pass the @code{this} pointer\n\
646	in C++. This is the incoming argument @emph{before} the function prologue,\n\
647	e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
648	all other incoming arguments.\n\
649	\n\
650	Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
651	made after adding @code{delta}. In particular, if @var{p} is the\n\
652	adjusted pointer, the following adjustment should be made:\n\
653	\n\
654	@smallexample\n\
655	p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
656	@end smallexample\n\
657	\n\
658	After the additions, emit code to jump to @var{function}, which is a\n\
659	@code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
660	not touch the return address. Hence returning from @var{FUNCTION} will\n\
661	return to whoever called the current @samp{thunk}.\n\
662	\n\
663	The effect must be as if @var{function} had been called directly with\n\
664	the adjusted first argument. This macro is responsible for emitting all\n\
665	of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
666	and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
667	\n\
668	The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
669	have already been extracted from it.) It might possibly be useful on\n\
670	some targets, but probably not.\n\
671	\n\
672	If you do not define this macro, the target-independent code in the C++\n\
673	front end will generate a less efficient heavyweight thunk that calls\n\
674	@var{function} instead of jumping to it. The generic approach does\n\
675	not support varargs.",
676	void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
677	HOST_WIDE_INT vcall_offset, tree function),
678	NULL)
679
680	/* Determine whether output_mi_thunk would succeed. */
681	/* ??? Ideally, this hook would not exist, and success or failure
682	would be returned from output_mi_thunk directly. But there's
683	too much undo-able setup involved in invoking output_mi_thunk.
684	Could be fixed by making output_mi_thunk emit rtl instead of
685	text to the output file. */
686	DEFHOOK
687	(can_output_mi_thunk,
688	"A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
689	to output the assembler code for the thunk function specified by the\n\
690	arguments it is passed, and false otherwise. In the latter case, the\n\
691	generic approach will be used by the C++ front end, with the limitations\n\
692	previously exposed.",
693	bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
694	HOST_WIDE_INT vcall_offset, const_tree function),
695	hook_bool_const_tree_hwi_hwi_const_tree_false)
696
697	/* Output any boilerplate text needed at the beginning of a
698	translation unit. */
699	DEFHOOK
700	(file_start,
701	"Output to @code{asm_out_file} any text which the assembler expects to\n\
702	find at the beginning of a file. The default behavior is controlled\n\
703	by two flags, documented below. Unless your target's assembler is\n\
704	quite unusual, if you override the default, you should call\n\
705	@code{default_file_start} at some point in your target hook. This\n\
706	lets other target files rely on these variables.",
707	void, (void),
708	default_file_start)
709
710	/* Output any boilerplate text needed at the end of a translation unit. */
711	DEFHOOK
712	(file_end,
713	"Output to @code{asm_out_file} any text which the assembler expects\n\
714	to find at the end of a file. The default is to output nothing.",
715	void, (void),
716	hook_void_void)
717
718	/* Output any boilerplate text needed at the beginning of an
719	LTO output stream. */
720	DEFHOOK
721	(lto_start,
722	"Output to @code{asm_out_file} any text which the assembler expects\n\
723	to find at the start of an LTO section. The default is to output\n\
724	nothing.",
725	void, (void),
726	hook_void_void)
727
728	/* Output any boilerplate text needed at the end of an
729	LTO output stream. */
730	DEFHOOK
731	(lto_end,
732	"Output to @code{asm_out_file} any text which the assembler expects\n\
733	to find at the end of an LTO section. The default is to output\n\
734	nothing.",
735	void, (void),
736	hook_void_void)
737
738	/* Output any boilerplace text needed at the end of a
739	translation unit before debug and unwind info is emitted. */
740	DEFHOOK
741	(code_end,
742	"Output to @code{asm_out_file} any text which is needed before emitting\n\
743	unwind info and debug info at the end of a file. Some targets emit\n\
744	here PIC setup thunks that cannot be emitted at the end of file,\n\
745	because they couldn't have unwind info then. The default is to output\n\
746	nothing.",
747	void, (void),
748	hook_void_void)
749
750	/* Output an assembler pseudo-op to declare a library function name
751	external. */
752	DEFHOOK
753	(external_libcall,
754	"This target hook is a function to output to @var{asm_out_file} an assembler\n\
755	pseudo-op to declare a library function name external. The name of the\n\
756	library function is given by @var{symref}, which is a @code{symbol_ref}.",
757	void, (rtx symref),
758	default_external_libcall)
759
760	/* Output an assembler directive to mark decl live. This instructs
761	linker to not dead code strip this symbol. */
762	DEFHOOK
763	(mark_decl_preserved,
764	"This target hook is a function to output to @var{asm_out_file} an assembler\n\
765	directive to annotate @var{symbol} as used. The Darwin target uses the\n\
766	.no_dead_code_strip directive.",
767	void, (const char *symbol),
768	hook_void_constcharptr)
769
770	/* Output a record of the command line switches that have been passed. */
771	DEFHOOK
772	(record_gcc_switches,
773	"Provides the target with the ability to record the gcc command line\n\
774	switches provided as argument.\n\
775	\n\
776	By default this hook is set to NULL, but an example implementation is\n\
777	provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
778	it records the switches as ASCII text inside a new, string mergeable\n\
779	section in the assembler output file. The name of the new section is\n\
780	provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
781	hook.",
782	void, (const char *),
783	NULL)
784
785	/* The name of the section that the example ELF implementation of
786	record_gcc_switches will use to store the information. Target
787	specific versions of record_gcc_switches may or may not use
788	this information. */
789	DEFHOOKPOD
790	(record_gcc_switches_section,
791	"This is the name of the section that will be created by the example\n\
792	ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
793	hook.",
794	const char *, ".GCC.command.line")
795
796	/* Output the definition of a section anchor. */
797	DEFHOOK
798	(output_anchor,
799	"Write the assembly code to define section anchor @var{x}, which is a\n\
800	@code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
801	The hook is called with the assembly output position set to the beginning\n\
802	of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
803	\n\
804	If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
805	it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
806	If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
807	is @code{NULL}, which disables the use of section anchors altogether.",
808	void, (rtx x),
809	default_asm_output_anchor)
810
811	DEFHOOK
812	(output_ident,
813	"Output a string based on @var{name}, suitable for the @samp{#ident}\n\
814	directive, or the equivalent directive or pragma in non-C-family languages.\n\
815	If this hook is not defined, nothing is output for the @samp{#ident}\n\
816	directive.",
817	void, (const char *name),
818	hook_void_constcharptr)
819
820	/* Output a DTP-relative reference to a TLS symbol. */
821	DEFHOOK
822	(output_dwarf_dtprel,
823	"If defined, this target hook is a function which outputs a DTP-relative\n\
824	reference to the given TLS symbol of the specified size.",
825	void, (FILE *file, int size, rtx x),
826	NULL)
827
828	/* Some target machines need to postscan each insn after it is output. */
829	DEFHOOK
830	(final_postscan_insn,
831	"If defined, this target hook is a function which is executed just after the\n\
832	output of assembler code for @var{insn}, to change the mode of the assembler\n\
833	if necessary.\n\
834	\n\
835	Here the argument @var{opvec} is the vector containing the operands\n\
836	extracted from @var{insn}, and @var{noperands} is the number of\n\
837	elements of the vector which contain meaningful data for this insn.\n\
838	The contents of this vector are what was used to convert the insn\n\
839	template into assembler code, so you can change the assembler mode\n\
840	by checking the contents of the vector.",
841	void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
842	NULL)
843
844	/* Emit the trampoline template. This hook may be NULL. */
845	DEFHOOK
846	(trampoline_template,
847	"This hook is called by @code{assemble_trampoline_template} to output,\n\
848	on the stream @var{f}, assembler code for a block of data that contains\n\
849	the constant parts of a trampoline. This code should not include a\n\
850	label---the label is taken care of automatically.\n\
851	\n\
852	If you do not define this hook, it means no template is needed\n\
853	for the target. Do not define this hook on systems where the block move\n\
854	code to copy the trampoline into place would be larger than the code\n\
855	to generate it on the spot.",
856	void, (FILE *f),
857	NULL)
858
859	DEFHOOK
860	(output_source_filename,
861	"Output DWARF debugging information which indicates that filename\n\
862	@var{name} is the current source file to the stdio stream @var{file}.\n\
863	\n\
864	This target hook need not be defined if the standard form of output\n\
865	for the file format in use is appropriate.",
866	void ,(FILE *file, const char *name),
867	default_asm_output_source_filename)
868
869	DEFHOOK
870	(output_addr_const_extra,
871	"A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
872	can't deal with, and output assembly code to @var{file} corresponding to\n\
873	the pattern @var{x}. This may be used to allow machine-dependent\n\
874	@code{UNSPEC}s to appear within constants.\n\
875	\n\
876	If target hook fails to recognize a pattern, it must return @code{false},\n\
877	so that a standard error message is printed. If it prints an error message\n\
878	itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
879	return @code{true}.",
880	bool, (FILE *file, rtx x),
881	hook_bool_FILEptr_rtx_false)
882
883	/* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
884	even though that is not reflected in the macro name to override their
885	initializers. */
886	#undef HOOK_PREFIX
887	#define HOOK_PREFIX "TARGET_"
888
889	/* Emit a machine-specific insn operand. */
890	/* ??? tm.texi only documents the old macro PRINT_OPERAND,
891	not this hook, and uses a different name for the argument FILE. */
892	DEFHOOK_UNDOC
893	(print_operand,
894	"",
895	void, (FILE *file, rtx x, int code),
896	default_print_operand)
897
898	/* Emit a machine-specific memory address. */
899	/* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
900	not this hook, and uses different argument names. */
901	DEFHOOK_UNDOC
902	(print_operand_address,
903	"",
904	void, (FILE *file, machine_mode mode, rtx addr),
905	default_print_operand_address)
906
907	/* Determine whether CODE is a valid punctuation character for the
908	`print_operand' hook. */
909	/* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
910	not this hook. */
911	DEFHOOK_UNDOC
912	(print_operand_punct_valid_p,
913	"",
914	bool ,(unsigned char code),
915	default_print_operand_punct_valid_p)
916
917	/* Given a symbol name, perform same mangling as assemble_name and
918	ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
919	DEFHOOK
920	(mangle_assembler_name,
921	"Given a symbol @var{name}, perform same mangling as @code{varasm.cc}'s\n\
922	@code{assemble_name}, but in memory rather than to a file stream, returning\n\
923	result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\n\
924	default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\n\
925	then prepends the @code{USER_LABEL_PREFIX}, if any.",
926	tree, (const char *name),
927	default_mangle_assembler_name)
928
929	HOOK_VECTOR_END (asm_out)
930
931	/* Functions relating to instruction scheduling. All of these
932	default to null pointers, which haifa-sched.cc looks for and handles. */
933	#undef HOOK_PREFIX
934	#define HOOK_PREFIX "TARGET_SCHED_"
935	HOOK_VECTOR (TARGET_SCHED, sched)
936
937	/* Given the current cost, COST, of an insn, INSN, calculate and
938	return a new cost based on its relationship to DEP_INSN through
939	the dependence LINK. The default is to make no adjustment. */
940	DEFHOOK
941	(adjust_cost,
942	"This function corrects the value of @var{cost} based on the\n\
943	relationship between @var{insn} and @var{dep_insn} through a\n\
944	dependence of type dep_type, and strength @var{dw}. It should return the new\n\
945	value. The default is to make no adjustment to @var{cost}. This can be\n\
946	used for example to specify to the scheduler using the traditional pipeline\n\
947	description that an output- or anti-dependence does not incur the same cost\n\
948	as a data-dependence. If the scheduler using the automaton based pipeline\n\
949	description, the cost of anti-dependence is zero and the cost of\n\
950	output-dependence is maximum of one and the difference of latency\n\
951	times of the first and the second insns. If these values are not\n\
952	acceptable, you could use the hook to modify them too. See also\n\
953	@pxref{Processor pipeline description}.",
954	int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
955	unsigned int dw),
956	NULL)
957
958	/* Adjust the priority of an insn as you see fit. Returns the new priority. */
959	DEFHOOK
960	(adjust_priority,
961	"This hook adjusts the integer scheduling priority @var{priority} of\n\
962	@var{insn}. It should return the new priority. Increase the priority to\n\
963	execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
964	later. Do not define this hook if you do not need to adjust the\n\
965	scheduling priorities of insns.",
966	int, (rtx_insn *insn, int priority), NULL)
967
968	/* Function which returns the maximum number of insns that can be
969	scheduled in the same machine cycle. This must be constant
970	over an entire compilation. The default is 1. */
971	DEFHOOK
972	(issue_rate,
973	"This hook returns the maximum number of instructions that can ever\n\
974	issue at the same time on the target machine. The default is one.\n\
975	Although the insn scheduler can define itself the possibility of issue\n\
976	an insn on the same cycle, the value can serve as an additional\n\
977	constraint to issue insns on the same simulated processor cycle (see\n\
978	hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
979	This value must be constant over the entire compilation. If you need\n\
980	it to vary depending on what the instructions are, you must use\n\
981	@samp{TARGET_SCHED_VARIABLE_ISSUE}.",
982	int, (void), NULL)
983
984	/* Calculate how much this insn affects how many more insns we
985	can emit this cycle. Default is they all cost the same. */
986	DEFHOOK
987	(variable_issue,
988	"This hook is executed by the scheduler after it has scheduled an insn\n\
989	from the ready list. It should return the number of insns which can\n\
990	still be issued in the current cycle. The default is\n\
991	@samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
992	@code{USE}, which normally are not counted against the issue rate.\n\
993	You should define this hook if some insns take more machine resources\n\
994	than others, so that fewer insns can follow them in the same cycle.\n\
995	@var{file} is either a null pointer, or a stdio stream to write any\n\
996	debug output to. @var{verbose} is the verbose level provided by\n\
997	@option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
998	was scheduled.",
999	int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
1000
1001	/* Initialize machine-dependent scheduling code. */
1002	DEFHOOK
1003	(init,
1004	"This hook is executed by the scheduler at the beginning of each block of\n\
1005	instructions that are to be scheduled. @var{file} is either a null\n\
1006	pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
1007	is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1008	@var{max_ready} is the maximum number of insns in the current scheduling\n\
1009	region that can be live at the same time. This can be used to allocate\n\
1010	scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1011	void, (FILE *file, int verbose, int max_ready), NULL)
1012
1013	/* Finalize machine-dependent scheduling code. */
1014	DEFHOOK
1015	(finish,
1016	"This hook is executed by the scheduler at the end of each block of\n\
1017	instructions that are to be scheduled. It can be used to perform\n\
1018	cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1019	is either a null pointer, or a stdio stream to write any debug output\n\
1020	to. @var{verbose} is the verbose level provided by\n\
1021	@option{-fsched-verbose-@var{n}}.",
1022	void, (FILE *file, int verbose), NULL)
1023
1024	/* Initialize machine-dependent function wide scheduling code. */
1025	DEFHOOK
1026	(init_global,
1027	"This hook is executed by the scheduler after function level initializations.\n\
1028	@var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1029	@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1030	@var{old_max_uid} is the maximum insn uid when scheduling begins.",
1031	void, (FILE *file, int verbose, int old_max_uid), NULL)
1032
1033	/* Finalize machine-dependent function wide scheduling code. */
1034	DEFHOOK
1035	(finish_global,
1036	"This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1037	@var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1038	@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1039	void, (FILE *file, int verbose), NULL)
1040
1041	/* Reorder insns in a machine-dependent fashion, in two different
1042	places. Default does nothing. */
1043	DEFHOOK
1044	(reorder,
1045	"This hook is executed by the scheduler after it has scheduled the ready\n\
1046	list, to allow the machine description to reorder it (for example to\n\
1047	combine two small instructions together on @samp{VLIW} machines).\n\
1048	@var{file} is either a null pointer, or a stdio stream to write any\n\
1049	debug output to. @var{verbose} is the verbose level provided by\n\
1050	@option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1051	list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1052	a pointer to the number of elements in the ready list. The scheduler\n\
1053	reads the ready list in reverse order, starting with\n\
1054	@var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1055	is the timer tick of the scheduler. You may modify the ready list and\n\
1056	the number of ready insns. The return value is the number of insns that\n\
1057	can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1058	@samp{TARGET_SCHED_REORDER2}.",
1059	int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1060
1061	DEFHOOK
1062	(reorder2,
1063	"Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1064	function is called whenever the scheduler starts a new cycle. This one\n\
1065	is called once per iteration over a cycle, immediately after\n\
1066	@samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1067	return the number of insns to be scheduled in the same cycle. Defining\n\
1068	this hook can be useful if there are frequent situations where\n\
1069	scheduling one insn causes other insns to become ready in the same\n\
1070	cycle. These other insns can then be taken into account properly.",
1071	int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1072
1073	DEFHOOK
1074	(macro_fusion_p,
1075	"This hook is used to check whether target platform supports macro fusion.",
1076	bool, (void), NULL)
1077
1078	DEFHOOK
1079	(macro_fusion_pair_p,
1080	"This hook is used to check whether two insns should be macro fused for\n\
1081	a target microarchitecture. If this hook returns true for the given insn pair\n\
1082	(@var{prev} and @var{curr}), the scheduler will put them into a sched\n\
1083	group, and they will not be scheduled apart. The two insns will be either\n\
1084	two SET insns or a compare and a conditional jump and this hook should\n\
1085	validate any dependencies needed to fuse the two insns together.",
1086	bool, (rtx_insn *prev, rtx_insn *curr), NULL)
1087
1088	/* The following member value is a pointer to a function called
1089	after evaluation forward dependencies of insns in chain given
1090	by two parameter values (head and tail correspondingly). */
1091	DEFHOOK
1092	(dependencies_evaluation_hook,
1093	"This hook is called after evaluation forward dependencies of insns in\n\
1094	chain given by two parameter values (@var{head} and @var{tail}\n\
1095	correspondingly) but before insns scheduling of the insn chain. For\n\
1096	example, it can be used for better insn classification if it requires\n\
1097	analysis of dependencies. This hook can use backward and forward\n\
1098	dependencies of the insn scheduler because they are already\n\
1099	calculated.",
1100	void, (rtx_insn *head, rtx_insn *tail), NULL)
1101
1102	/* The values of the following four members are pointers to functions
1103	used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1104	dfa_post_cycle_insn give functions returning insns which are used to
1105	change the pipeline hazard recognizer state when the new simulated
1106	processor cycle correspondingly starts and finishes. The function
1107	defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1108	used to initialize the corresponding insns. The default values of
1109	the members result in not changing the automaton state when the
1110	new simulated processor cycle correspondingly starts and finishes. */
1111
1112	DEFHOOK
1113	(init_dfa_pre_cycle_insn,
1114	"The hook can be used to initialize data used by the previous hook.",
1115	void, (void), NULL)
1116
1117	DEFHOOK
1118	(dfa_pre_cycle_insn,
1119	"The hook returns an RTL insn. The automaton state used in the\n\
1120	pipeline hazard recognizer is changed as if the insn were scheduled\n\
1121	when the new simulated processor cycle starts. Usage of the hook may\n\
1122	simplify the automaton pipeline description for some @acronym{VLIW}\n\
1123	processors. If the hook is defined, it is used only for the automaton\n\
1124	based pipeline description. The default is not to change the state\n\
1125	when the new simulated processor cycle starts.",
1126	rtx, (void), NULL)
1127
1128	DEFHOOK
1129	(init_dfa_post_cycle_insn,
1130	"The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1131	used to initialize data used by the previous hook.",
1132	void, (void), NULL)
1133
1134	DEFHOOK
1135	(dfa_post_cycle_insn,
1136	"The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1137	to changed the state as if the insn were scheduled when the new\n\
1138	simulated processor cycle finishes.",
1139	rtx_insn *, (void), NULL)
1140
1141	/* The values of the following two members are pointers to
1142	functions used to simplify the automaton descriptions.
1143	dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1144	immediately before and after cycle is advanced. */
1145
1146	DEFHOOK
1147	(dfa_pre_advance_cycle,
1148	"The hook to notify target that the current simulated cycle is about to finish.\n\
1149	The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1150	to change the state in more complicated situations - e.g., when advancing\n\
1151	state on a single insn is not enough.",
1152	void, (void), NULL)
1153
1154	DEFHOOK
1155	(dfa_post_advance_cycle,
1156	"The hook to notify target that new simulated cycle has just started.\n\
1157	The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1158	to change the state in more complicated situations - e.g., when advancing\n\
1159	state on a single insn is not enough.",
1160	void, (void), NULL)
1161
1162	/* The following member value is a pointer to a function returning value
1163	which defines how many insns in queue `ready' will we try for
1164	multi-pass scheduling. If the member value is nonzero and the
1165	function returns positive value, the DFA based scheduler will make
1166	multi-pass scheduling for the first cycle. In other words, we will
1167	try to choose ready insn which permits to start maximum number of
1168	insns on the same cycle. */
1169	DEFHOOK
1170	(first_cycle_multipass_dfa_lookahead,
1171	"This hook controls better choosing an insn from the ready insn queue\n\
1172	for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1173	chooses the first insn from the queue. If the hook returns a positive\n\
1174	value, an additional scheduler code tries all permutations of\n\
1175	@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1176	subsequent ready insns to choose an insn whose issue will result in\n\
1177	maximal number of issued insns on the same cycle. For the\n\
1178	@acronym{VLIW} processor, the code could actually solve the problem of\n\
1179	packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1180	rules of @acronym{VLIW} packing are described in the automaton.\n\
1181	\n\
1182	This code also could be used for superscalar @acronym{RISC}\n\
1183	processors. Let us consider a superscalar @acronym{RISC} processor\n\
1184	with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1185	@var{B}, some insns can be executed only in pipelines @var{B} or\n\
1186	@var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1187	processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1188	@var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1189	until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1190	the processor could issue all 3 insns per cycle.\n\
1191	\n\
1192	Actually this code demonstrates advantages of the automaton based\n\
1193	pipeline hazard recognizer. We try quickly and easy many insn\n\
1194	schedules to choose the best one.\n\
1195	\n\
1196	The default is no multipass scheduling.",
1197	int, (void), NULL)
1198
1199	/* The following member value is pointer to a function controlling
1200	what insns from the ready insn queue will be considered for the
1201	multipass insn scheduling. If the hook returns zero for insn
1202	passed as the parameter, the insn will be not chosen to be issued. */
1203	DEFHOOK
1204	(first_cycle_multipass_dfa_lookahead_guard,
1205	"\n\
1206	This hook controls what insns from the ready insn queue will be\n\
1207	considered for the multipass insn scheduling. If the hook returns\n\
1208	zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1209	Positive return values will remove @var{insn} from consideration on\n\
1210	the current round of multipass scheduling.\n\
1211	Negative return values will remove @var{insn} from consideration for given\n\
1212	number of cycles.\n\
1213	Backends should be careful about returning non-zero for highest priority\n\
1214	instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1215	to allow backends make correct judgements.\n\
1216	\n\
1217	The default is that any ready insns can be chosen to be issued.",
1218	int, (rtx_insn *insn, int ready_index), NULL)
1219
1220	/* This hook prepares the target for a new round of multipass
1221	scheduling.
1222	DATA is a pointer to target-specific data used for multipass scheduling.
1223	READY_TRY and N_READY represent the current state of search in the
1224	optimization space. The target can filter out instructions that
1225	should not be tried during current round by setting corresponding
1226	elements in READY_TRY to non-zero.
1227	FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1228	scheduling on current cycle. */
1229	DEFHOOK
1230	(first_cycle_multipass_begin,
1231	"This hook prepares the target backend for a new round of multipass\n\
1232	scheduling.",
1233	void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1234	NULL)
1235
1236	/* This hook is called when multipass scheduling evaluates instruction INSN.
1237	DATA is a pointer to target-specific data that can be used to record effects
1238	of INSN on CPU that are not described in DFA.
1239	READY_TRY and N_READY represent the current state of search in the
1240	optimization space. The target can filter out instructions that
1241	should not be tried after issuing INSN by setting corresponding
1242	elements in READY_TRY to non-zero.
1243	INSN is the instruction being evaluated.
1244	PREV_DATA is a pointer to target-specific data corresponding
1245	to a state before issuing INSN. */
1246	DEFHOOK
1247	(first_cycle_multipass_issue,
1248	"This hook is called when multipass scheduling evaluates instruction INSN.",
1249	void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1250	const void *prev_data), NULL)
1251
1252	/* This hook is called when multipass scheduling backtracks from evaluation of
1253	instruction corresponding to DATA.
1254	DATA is a pointer to target-specific data that stores the effects
1255	of instruction from which the algorithm backtracks on CPU that are not
1256	described in DFA.
1257	READY_TRY and N_READY represent the current state of search in the
1258	optimization space. The target can filter out instructions that
1259	should not be tried after issuing INSN by setting corresponding
1260	elements in READY_TRY to non-zero. */
1261	DEFHOOK
1262	(first_cycle_multipass_backtrack,
1263	"This is called when multipass scheduling backtracks from evaluation of\n\
1264	an instruction.",
1265	void, (const void *data, signed char *ready_try, int n_ready), NULL)
1266
1267	/* This hook notifies the target about the result of the concluded current
1268	round of multipass scheduling.
1269	DATA is a pointer.
1270	If DATA is non-NULL it points to target-specific data used for multipass
1271	scheduling which corresponds to instruction at the start of the chain of
1272	the winning solution. DATA is NULL when multipass scheduling cannot find
1273	a good enough solution on current cycle and decides to retry later,
1274	usually after advancing the cycle count. */
1275	DEFHOOK
1276	(first_cycle_multipass_end,
1277	"This hook notifies the target about the result of the concluded current\n\
1278	round of multipass scheduling.",
1279	void, (const void *data), NULL)
1280
1281	/* This hook is called to initialize target-specific data for multipass
1282	scheduling after it has been allocated.
1283	DATA is a pointer to target-specific data that stores the effects
1284	of instruction from which the algorithm backtracks on CPU that are not
1285	described in DFA. */
1286	DEFHOOK
1287	(first_cycle_multipass_init,
1288	"This hook initializes target-specific data used in multipass scheduling.",
1289	void, (void *data), NULL)
1290
1291	/* This hook is called to finalize target-specific data for multipass
1292	scheduling before it is deallocated.
1293	DATA is a pointer to target-specific data that stores the effects
1294	of instruction from which the algorithm backtracks on CPU that are not
1295	described in DFA. */
1296	DEFHOOK
1297	(first_cycle_multipass_fini,
1298	"This hook finalizes target-specific data used in multipass scheduling.",
1299	void, (void *data), NULL)
1300
1301	/* The following member value is pointer to a function called by
1302	the insn scheduler before issuing insn passed as the third
1303	parameter on given cycle. If the hook returns nonzero, the
1304	insn is not issued on given processors cycle. Instead of that,
1305	the processor cycle is advanced. If the value passed through
1306	the last parameter is zero, the insn ready queue is not sorted
1307	on the new cycle start as usually. The first parameter passes
1308	file for debugging output. The second one passes the scheduler
1309	verbose level of the debugging output. The forth and the fifth
1310	parameter values are correspondingly processor cycle on which
1311	the previous insn has been issued and the current processor cycle. */
1312	DEFHOOK
1313	(dfa_new_cycle,
1314	"This hook is called by the insn scheduler before issuing @var{insn}\n\
1315	on cycle @var{clock}. If the hook returns nonzero,\n\
1316	@var{insn} is not issued on this processor cycle. Instead,\n\
1317	the processor cycle is advanced. If *@var{sort_p}\n\
1318	is zero, the insn ready queue is not sorted on the new cycle\n\
1319	start as usually. @var{dump} and @var{verbose} specify the file and\n\
1320	verbosity level to use for debugging output.\n\
1321	@var{last_clock} and @var{clock} are, respectively, the\n\
1322	processor cycle on which the previous insn has been issued,\n\
1323	and the current processor cycle.",
1324	int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1325	int clock, int *sort_p),
1326	NULL)
1327
1328	/* The following member value is a pointer to a function called by the
1329	insn scheduler. It should return true if there exists a dependence
1330	which is considered costly by the target, between the insn
1331	DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1332	the dep that represents the dependence between the two insns. The
1333	second argument is the cost of the dependence as estimated by
1334	the scheduler. The last argument is the distance in cycles
1335	between the already scheduled insn (first parameter) and the
1336	second insn (second parameter). */
1337	DEFHOOK
1338	(is_costly_dependence,
1339	"This hook is used to define which dependences are considered costly by\n\
1340	the target, so costly that it is not advisable to schedule the insns that\n\
1341	are involved in the dependence too close to one another. The parameters\n\
1342	to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1343	being evaluated. The second parameter @var{cost} is the cost of the\n\
1344	dependence as estimated by the scheduler, and the third\n\
1345	parameter @var{distance} is the distance in cycles between the two insns.\n\
1346	The hook returns @code{true} if considering the distance between the two\n\
1347	insns the dependence between them is considered costly by the target,\n\
1348	and @code{false} otherwise.\n\
1349	\n\
1350	Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1351	where (a) it's practically hopeless to predict the actual data/resource\n\
1352	delays, however: (b) there's a better chance to predict the actual grouping\n\
1353	that will be formed, and (c) correctly emulating the grouping can be very\n\
1354	important. In such targets one may want to allow issuing dependent insns\n\
1355	closer to one another---i.e., closer than the dependence distance; however,\n\
1356	not in cases of ``costly dependences'', which this hooks allows to define.",
1357	bool, (struct _dep *_dep, int cost, int distance), NULL)
1358
1359	/* The following member value is a pointer to a function called
1360	by the insn scheduler. This hook is called to notify the backend
1361	that new instructions were emitted. */
1362	DEFHOOK
1363	(h_i_d_extended,
1364	"This hook is called by the insn scheduler after emitting a new instruction to\n\
1365	the instruction stream. The hook notifies a target backend to extend its\n\
1366	per instruction data structures.",
1367	void, (void), NULL)
1368
1369	/* Next 5 functions are for multi-point scheduling. */
1370
1371	/* Allocate memory for scheduler context. */
1372	DEFHOOK
1373	(alloc_sched_context,
1374	"Return a pointer to a store large enough to hold target scheduling context.",
1375	void *, (void), NULL)
1376
1377	/* Fills the context from the local machine scheduler context. */
1378	DEFHOOK
1379	(init_sched_context,
1380	"Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1381	It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1382	beginning of the block. Otherwise, copy the current context into @var{tc}.",
1383	void, (void *tc, bool clean_p), NULL)
1384
1385	/* Sets local machine scheduler context to a saved value. */
1386	DEFHOOK
1387	(set_sched_context,
1388	"Copy target scheduling context pointed to by @var{tc} to the current context.",
1389	void, (void *tc), NULL)
1390
1391	/* Clears a scheduler context so it becomes like after init. */
1392	DEFHOOK
1393	(clear_sched_context,
1394	"Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1395	void, (void *tc), NULL)
1396
1397	/* Frees the scheduler context. */
1398	DEFHOOK
1399	(free_sched_context,
1400	"Deallocate a store for target scheduling context pointed to by @var{tc}.",
1401	void, (void *tc), NULL)
1402
1403	/* The following member value is a pointer to a function called
1404	by the insn scheduler.
1405	The first parameter is an instruction, the second parameter is the type
1406	of the requested speculation, and the third parameter is a pointer to the
1407	speculative pattern of the corresponding type (set if return value == 1).
1408	It should return
1409	-1, if there is no pattern, that will satisfy the requested speculation type,
1410	0, if current pattern satisfies the requested speculation type,
1411	1, if pattern of the instruction should be changed to the newly
1412	generated one. */
1413	DEFHOOK
1414	(speculate_insn,
1415	"This hook is called by the insn scheduler when @var{insn} has only\n\
1416	speculative dependencies and therefore can be scheduled speculatively.\n\
1417	The hook is used to check if the pattern of @var{insn} has a speculative\n\
1418	version and, in case of successful check, to generate that speculative\n\
1419	pattern. The hook should return 1, if the instruction has a speculative form,\n\
1420	or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1421	speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1422	the generated speculative pattern.",
1423	int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1424
1425	/* The following member value is a pointer to a function called
1426	by the insn scheduler. It should return true if the check instruction
1427	passed as the parameter needs a recovery block. */
1428	DEFHOOK
1429	(needs_block_p,
1430	"This hook is called by the insn scheduler during generation of recovery code\n\
1431	for @var{insn}. It should return @code{true}, if the corresponding check\n\
1432	instruction should branch to recovery code, or @code{false} otherwise.",
1433	bool, (unsigned int dep_status), NULL)
1434
1435	/* The following member value is a pointer to a function called
1436	by the insn scheduler. It should return a pattern for the check
1437	instruction.
1438	The first parameter is a speculative instruction, the second parameter
1439	is the label of the corresponding recovery block (or null, if it is a
1440	simple check). The third parameter is the kind of speculation that
1441	is being performed. */
1442	DEFHOOK
1443	(gen_spec_check,
1444	"This hook is called by the insn scheduler to generate a pattern for recovery\n\
1445	check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1446	speculative instruction for which the check should be generated.\n\
1447	@var{label} is either a label of a basic block, where recovery code should\n\
1448	be emitted, or a null pointer, when requested check doesn't branch to\n\
1449	recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1450	a pattern for a branchy check corresponding to a simple check denoted by\n\
1451	@var{insn} should be generated. In this case @var{label} can't be null.",
1452	rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1453
1454	/* The following member value is a pointer to a function that provides
1455	information about the speculation capabilities of the target.
1456	The parameter is a pointer to spec_info variable. */
1457	DEFHOOK
1458	(set_sched_flags,
1459	"This hook is used by the insn scheduler to find out what features should be\n\
1460	enabled/used.\n\
1461	The structure *@var{spec_info} should be filled in by the target.\n\
1462	The structure describes speculation types that can be used in the scheduler.",
1463	void, (struct spec_info_def *spec_info), NULL)
1464
1465	DEFHOOK_UNDOC
1466	(get_insn_spec_ds,
1467	"Return speculation types of instruction @var{insn}.",
1468	unsigned int, (rtx_insn *insn), NULL)
1469
1470	DEFHOOK_UNDOC
1471	(get_insn_checked_ds,
1472	"Return speculation types that are checked for instruction @var{insn}",
1473	unsigned int, (rtx_insn *insn), NULL)
1474
1475	DEFHOOK
1476	(can_speculate_insn,
1477	"Some instructions should never be speculated by the schedulers, usually\n\
1478	because the instruction is too expensive to get this wrong. Often such\n\
1479	instructions have long latency, and often they are not fully modeled in the\n\
1480	pipeline descriptions. This hook should return @code{false} if @var{insn}\n\
1481	should not be speculated.",
1482	bool, (rtx_insn *insn), hook_bool_rtx_insn_true)
1483
1484	DEFHOOK_UNDOC
1485	(skip_rtx_p,
1486	"Return bool if rtx scanning should just skip current layer and\
1487	advance to the inner rtxes.",
1488	bool, (const_rtx x), NULL)
1489
1490	/* The following member value is a pointer to a function that provides
1491	information about the target resource-based lower bound which is
1492	used by the swing modulo scheduler. The parameter is a pointer
1493	to ddg variable. */
1494	DEFHOOK
1495	(sms_res_mii,
1496	"This hook is called by the swing modulo scheduler to calculate a\n\
1497	resource-based lower bound which is based on the resources available in\n\
1498	the machine and the resources required by each instruction. The target\n\
1499	backend can use @var{g} to calculate such bound. A very simple lower\n\
1500	bound will be used in case this hook is not implemented: the total number\n\
1501	of instructions divided by the issue rate.",
1502	int, (struct ddg *g), NULL)
1503
1504	/* The following member value is a function that initializes dispatch
1505	schedling and adds instructions to dispatch window according to its
1506	parameters. */
1507	DEFHOOK
1508	(dispatch_do,
1509	"This hook is called by Haifa Scheduler. It performs the operation specified\n\
1510	in its second parameter.",
1511	void, (rtx_insn *insn, int x),
1512	hook_void_rtx_insn_int)
1513
1514	/* The following member value is a function that returns true is
1515	dispatch schedling is supported in hardware and condition passed
1516	as the second parameter is true. */
1517	DEFHOOK
1518	(dispatch,
1519	"This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1520	is supported in hardware and the condition specified in the parameter is true.",
1521	bool, (rtx_insn *insn, int x),
1522	hook_bool_rtx_insn_int_false)
1523
1524	DEFHOOKPOD
1525	(exposed_pipeline,
1526	"True if the processor has an exposed pipeline, which means that not just\n\
1527	the order of instructions is important for correctness when scheduling, but\n\
1528	also the latencies of operations.",
1529	bool, false)
1530
1531	/* The following member value is a function that returns number
1532	of operations reassociator should try to put in parallel for
1533	statements of the given type. By default 1 is used. */
1534	DEFHOOK
1535	(reassociation_width,
1536	"This hook is called by tree reassociator to determine a level of\n\
1537	parallelism required in output calculations chain.",
1538	int, (unsigned int opc, machine_mode mode),
1539	hook_int_uint_mode_1)
1540
1541	/* The following member value is a function that returns priority for
1542	fusion of each instruction via pointer parameters. */
1543	DEFHOOK
1544	(fusion_priority,
1545	"This hook is called by scheduling fusion pass. It calculates fusion\n\
1546	priorities for each instruction passed in by parameter. The priorities\n\
1547	are returned via pointer parameters.\n\
1548	\n\
1549	@var{insn} is the instruction whose priorities need to be calculated.\n\
1550	@var{max_pri} is the maximum priority can be returned in any cases.\n\
1551	@var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1552	fusion priority should be calculated and returned.\n\
1553	@var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1554	should be calculated and returned.\n\
1555	\n\
1556	Same @var{fusion_pri} should be returned for instructions which should\n\
1557	be scheduled together. Different @var{pri} should be returned for\n\
1558	instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1559	sort key, @var{pri} is the minor sort key. All instructions will be\n\
1560	scheduled according to the two priorities. All priorities calculated\n\
1561	should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1562	false dependencies, @var{fusion_pri} of instructions which need to be\n\
1563	scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1564	instructions.\n\
1565	\n\
1566	Given below example:\n\
1567	\n\
1568	@smallexample\n\
1569	ldr r10, [r1, 4]\n\
1570	add r4, r4, r10\n\
1571	ldr r15, [r2, 8]\n\
1572	sub r5, r5, r15\n\
1573	ldr r11, [r1, 0]\n\
1574	add r4, r4, r11\n\
1575	ldr r16, [r2, 12]\n\
1576	sub r5, r5, r16\n\
1577	@end smallexample\n\
1578	\n\
1579	On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1580	merged. Since peephole2 pass can't help in this case unless consecutive\n\
1581	loads are actually next to each other in instruction flow. That's where\n\
1582	this scheduling fusion pass works. This hook calculates priority for each\n\
1583	instruction based on its fustion type, like:\n\
1584	\n\
1585	@smallexample\n\
1586	ldr r10, [r1, 4] ; fusion_pri=99, pri=96\n\
1587	add r4, r4, r10 ; fusion_pri=100, pri=100\n\
1588	ldr r15, [r2, 8] ; fusion_pri=98, pri=92\n\
1589	sub r5, r5, r15 ; fusion_pri=100, pri=100\n\
1590	ldr r11, [r1, 0] ; fusion_pri=99, pri=100\n\
1591	add r4, r4, r11 ; fusion_pri=100, pri=100\n\
1592	ldr r16, [r2, 12] ; fusion_pri=98, pri=88\n\
1593	sub r5, r5, r16 ; fusion_pri=100, pri=100\n\
1594	@end smallexample\n\
1595	\n\
1596	Scheduling fusion pass then sorts all ready to issue instructions according\n\
1597	to the priorities. As a result, instructions of same fusion type will be\n\
1598	pushed together in instruction flow, like:\n\
1599	\n\
1600	@smallexample\n\
1601	ldr r11, [r1, 0]\n\
1602	ldr r10, [r1, 4]\n\
1603	ldr r15, [r2, 8]\n\
1604	ldr r16, [r2, 12]\n\
1605	add r4, r4, r10\n\
1606	sub r5, r5, r15\n\
1607	add r4, r4, r11\n\
1608	sub r5, r5, r16\n\
1609	@end smallexample\n\
1610	\n\
1611	Now peephole2 pass can simply merge the two pairs of loads.\n\
1612	\n\
1613	Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1614	work, it is only enabled by default when peephole2 is in effect.\n\
1615	\n\
1616	This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1617	the hook implementation for how different fusion types are supported.",
1618	void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1619
1620	HOOK_VECTOR_END (sched)
1621
1622	/* Functions relating to OpenMP SIMD and __attribute__((simd)) clones. */
1623	#undef HOOK_PREFIX
1624	#define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1625	HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1626
1627	DEFHOOK
1628	(compute_vecsize_and_simdlen,
1629	"This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1630	fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1631	@var{simdlen} field if it was previously 0.\n\
1632	@var{vecsize_mangle} is a marker for the backend only. @var{vecsize_int} and\n\
1633	@var{vecsize_float} should be left zero on targets where the number of lanes is\n\
1634	not determined by the bitsize (in which case @var{simdlen} is always used).\n\
1635	The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1636	or number of @var{vecsize_mangle} variants that should be emitted.",
1637	int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int, bool), NULL)
1638
1639	DEFHOOK
1640	(adjust,
1641	"This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1642	to SIMD clone @var{node} if needed.",
1643	void, (struct cgraph_node *), NULL)
1644
1645	DEFHOOK
1646	(usable,
1647	"This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1648	in vectorized loops in current function, or non-negative number if it is\n\
1649	usable. In that case, the smaller the number is, the more desirable it is\n\
1650	to use it.",
1651	int, (struct cgraph_node *), NULL)
1652
1653	HOOK_VECTOR_END (simd_clone)
1654
1655	/* Functions relating to OpenMP SIMT vectorization transform. */
1656	#undef HOOK_PREFIX
1657	#define HOOK_PREFIX "TARGET_SIMT_"
1658	HOOK_VECTOR (TARGET_SIMT, simt)
1659
1660	DEFHOOK
1661	(vf,
1662	"Return number of threads in SIMT thread group on the target.",
1663	int, (void), NULL)
1664
1665	HOOK_VECTOR_END (simt)
1666
1667	/* Functions relating to OpenMP. */
1668	#undef HOOK_PREFIX
1669	#define HOOK_PREFIX "TARGET_OMP_"
1670	HOOK_VECTOR (TARGET_OMP, omp)
1671
1672	DEFHOOK
1673	(device_kind_arch_isa,
1674	"Return 1 if @var{trait} @var{name} is present in the OpenMP context's\n\
1675	device trait set, return 0 if not present in any OpenMP context in the\n\
1676	whole translation unit, or -1 if not present in the current OpenMP context\n\
1677	but might be present in another OpenMP context in the same TU.",
1678	int, (enum omp_device_kind_arch_isa trait, const char *name), NULL)
1679
1680	HOOK_VECTOR_END (omp)
1681
1682	/* Functions relating to openacc. */
1683	#undef HOOK_PREFIX
1684	#define HOOK_PREFIX "TARGET_GOACC_"
1685	HOOK_VECTOR (TARGET_GOACC, goacc)
1686
1687	DEFHOOK
1688	(validate_dims,
1689	"This hook should check the launch dimensions provided for an OpenACC\n\
1690	compute region, or routine. Defaulted values are represented as -1\n\
1691	and non-constant values as 0. The @var{fn_level} is negative for the\n\
1692	function corresponding to the compute region. For a routine it is the\n\
1693	outermost level at which partitioned execution may be spawned. The hook\n\
1694	should verify non-default values. If DECL is NULL, global defaults\n\
1695	are being validated and unspecified defaults should be filled in.\n\
1696	Diagnostics should be issued as appropriate. Return\n\
1697	true, if changes have been made. You must override this hook to\n\
1698	provide dimensions larger than 1.",
1699	bool, (tree decl, int *dims, int fn_level, unsigned used),
1700	default_goacc_validate_dims)
1701
1702	DEFHOOK
1703	(dim_limit,
1704	"This hook should return the maximum size of a particular dimension,\n\
1705	or zero if unbounded.",
1706	int, (int axis),
1707	default_goacc_dim_limit)
1708
1709	DEFHOOK
1710	(fork_join,
1711	"This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN\n\
1712	function calls to target-specific gimple, or indicate whether they\n\
1713	should be retained. It is executed during the oacc_device_lower pass.\n\
1714	It should return true, if the call should be retained. It should\n\
1715	return false, if it is to be deleted (either because target-specific\n\
1716	gimple has been inserted before it, or there is no need for it).\n\
1717	The default hook returns false, if there are no RTL expanders for them.",
1718	bool, (gcall *call, const int *dims, bool is_fork),
1719	default_goacc_fork_join)
1720
1721	DEFHOOK
1722	(reduction,
1723	"This hook is used by the oacc_transform pass to expand calls to the\n\
1724	@var{GOACC_REDUCTION} internal function, into a sequence of gimple\n\
1725	instructions. @var{call} is gimple statement containing the call to\n\
1726	the function. This hook removes statement @var{call} after the\n\
1727	expanded sequence has been inserted. This hook is also responsible\n\
1728	for allocating any storage for reductions when necessary.",
1729	void, (gcall *call),
1730	default_goacc_reduction)
1731
1732	DEFHOOK
1733	(adjust_private_decl,
1734	"This hook, if defined, is used by accelerator target back-ends to adjust\n\
1735	OpenACC variable declarations that should be made private to the given\n\
1736	parallelism level (i.e. @code{GOMP_DIM_GANG}, @code{GOMP_DIM_WORKER} or\n\
1737	@code{GOMP_DIM_VECTOR}). A typical use for this hook is to force variable\n\
1738	declarations at the @code{gang} level to reside in GPU shared memory.\n\
1739	@var{loc} may be used for diagnostic purposes.\n\
1740	\n\
1741	You may also use the @code{TARGET_GOACC_EXPAND_VAR_DECL} hook if the\n\
1742	adjusted variable declaration needs to be expanded to RTL in a non-standard\n\
1743	way.",
1744	tree, (location_t loc, tree var, int level),
1745	NULL)
1746
1747	DEFHOOK
1748	(expand_var_decl,
1749	"This hook, if defined, is used by accelerator target back-ends to expand\n\
1750	specially handled kinds of @code{VAR_DECL} expressions. A particular use is\n\
1751	to place variables with specific attributes inside special accelarator\n\
1752	memories. A return value of @code{NULL} indicates that the target does not\n\
1753	handle this @code{VAR_DECL}, and normal RTL expanding is resumed.\n\
1754	\n\
1755	Only define this hook if your accelerator target needs to expand certain\n\
1756	@code{VAR_DECL} nodes in a way that differs from the default. You can also adjust\n\
1757	private variables at OpenACC device-lowering time using the\n\
1758	@code{TARGET_GOACC_ADJUST_PRIVATE_DECL} target hook.",
1759	rtx, (tree var),
1760	NULL)
1761
1762	DEFHOOK
1763	(create_worker_broadcast_record,
1764	"Create a record used to propagate local-variable state from an active\n\
1765	worker to other workers. A possible implementation might adjust the type\n\
1766	of REC to place the new variable in shared GPU memory.\n\
1767	\n\
1768	Presence of this target hook indicates that middle end neutering/broadcasting\n\
1769	be used.",
1770	tree, (tree rec, bool sender, const char *name, unsigned HOST_WIDE_INT offset),
1771	NULL)
1772
1773	DEFHOOK
1774	(shared_mem_layout,
1775	"Lay out a fixed shared-memory region on the target. The LO and HI\n\
1776	arguments should be set to a range of addresses that can be used for worker\n\
1777	broadcasting. The dimensions, reduction size and gang-private size\n\
1778	arguments are for the current offload region.",
1779	void, (unsigned HOST_WIDE_INT *, unsigned HOST_WIDE_INT *, int[],
1780	unsigned HOST_WIDE_INT[], unsigned HOST_WIDE_INT[]),
1781	NULL)
1782
1783	HOOK_VECTOR_END (goacc)
1784
1785	/* Functions relating to vectorization. */
1786	#undef HOOK_PREFIX
1787	#define HOOK_PREFIX "TARGET_VECTORIZE_"
1788	HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1789
1790	/* The following member value is a pointer to a function called
1791	by the vectorizer, and return the decl of the target builtin
1792	function. */
1793	DEFHOOK
1794	(builtin_mask_for_load,
1795	"This hook should return the DECL of a function @var{f} that given an\n\
1796	address @var{addr} as an argument returns a mask @var{m} that can be\n\
1797	used to extract from two vectors the relevant data that resides in\n\
1798	@var{addr} in case @var{addr} is not properly aligned.\n\
1799	\n\
1800	The autovectorizer, when vectorizing a load operation from an address\n\
1801	@var{addr} that may be unaligned, will generate two vector loads from\n\
1802	the two aligned addresses around @var{addr}. It then generates a\n\
1803	@code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1804	two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1805	@var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1806	the third argument, @var{OFF}, defines how the data will be extracted\n\
1807	from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1808	@var{v2}; otherwise, the returned vector is composed from the last\n\
1809	@var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1810	@var{OFF} elements of @var{v2}.\n\
1811	\n\
1812	If this hook is defined, the autovectorizer will generate a call\n\
1813	to @var{f} (using the DECL tree that this hook returns) and will\n\
1814	use the return value of @var{f} as the argument @var{OFF} to\n\
1815	@code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1816	should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1817	described above.\n\
1818	If this hook is not defined, then @var{addr} will be used as\n\
1819	the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1820	log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1821	tree, (void), NULL)
1822
1823	/* Returns a built-in function that realizes the vectorized version of
1824	a target-independent function, or NULL_TREE if not available. */
1825	DEFHOOK
1826	(builtin_vectorized_function,
1827	"This hook should return the decl of a function that implements the\n\
1828	vectorized variant of the function with the @code{combined_fn} code\n\
1829	@var{code} or @code{NULL_TREE} if such a function is not available.\n\
1830	The return type of the vectorized function shall be of vector type\n\
1831	@var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1832	tree, (unsigned code, tree vec_type_out, tree vec_type_in),
1833	default_builtin_vectorized_function)
1834
1835	/* Returns a built-in function that realizes the vectorized version of
1836	a target-specific function, or NULL_TREE if not available. */
1837	DEFHOOK
1838	(builtin_md_vectorized_function,
1839	"This hook should return the decl of a function that implements the\n\
1840	vectorized variant of target built-in function @code{fndecl}. The\n\
1841	return type of the vectorized function shall be of vector type\n\
1842	@var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1843	tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1844	default_builtin_md_vectorized_function)
1845
1846	/* Cost of different vector/scalar statements in vectorization cost
1847	model. In case of misaligned vector loads and stores the cost depends
1848	on the data type and misalignment value. */
1849	DEFHOOK
1850	(builtin_vectorization_cost,
1851	"Returns cost of different scalar or vector statements for vectorization cost model.\n\
1852	For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1853	misalignment value (@var{misalign}).",
1854	int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1855	default_builtin_vectorization_cost)
1856
1857	DEFHOOK
1858	(preferred_vector_alignment,
1859	"This hook returns the preferred alignment in bits for accesses to\n\
1860	vectors of type @var{type} in vectorized code. This might be less than\n\
1861	or greater than the ABI-defined value returned by\n\
1862	@code{TARGET_VECTOR_ALIGNMENT}. It can be equal to the alignment of\n\
1863	a single element, in which case the vectorizer will not try to optimize\n\
1864	for alignment.\n\
1865	\n\
1866	The default hook returns @code{TYPE_ALIGN (@var{type})}, which is\n\
1867	correct for most targets.",
1868	poly_uint64, (const_tree type),
1869	default_preferred_vector_alignment)
1870
1871	/* Returns whether the target has a preference for decomposing divisions using
1872	shifts rather than multiplies. */
1873	DEFHOOK
1874	(preferred_div_as_shifts_over_mult,
1875	"Sometimes it is possible to implement a vector division using a sequence\n\
1876	of two addition-shift pairs, giving four instructions in total.\n\
1877	Return true if taking this approach for @var{vectype} is likely\n\
1878	to be better than using a sequence involving highpart multiplication.\n\
1879	Default is false if @code{can_mult_highpart_p}, otherwise true.",
1880	bool, (const_tree type),
1881	default_preferred_div_as_shifts_over_mult)
1882
1883	/* Return true if vector alignment is reachable (by peeling N
1884	iterations) for the given scalar type. */
1885	DEFHOOK
1886	(vector_alignment_reachable,
1887	"Return true if vector alignment is reachable (by peeling N iterations)\n\
1888	for the given scalar type @var{type}. @var{is_packed} is false if the scalar\n\
1889	access using @var{type} is known to be naturally aligned.",
1890	bool, (const_tree type, bool is_packed),
1891	default_builtin_vector_alignment_reachable)
1892
1893	DEFHOOK
1894	(vec_perm_const,
1895	"This hook is used to test whether the target can permute up to two\n\
1896	vectors of mode @var{op_mode} using the permutation vector @code{sel},\n\
1897	producing a vector of mode @var{mode}. The hook is also used to emit such\n\
1898	a permutation.\n\
1899	\n\
1900	When the hook is being used to test whether the target supports a permutation,\n\
1901	@var{in0}, @var{in1}, and @var{out} are all null. When the hook is being used\n\
1902	to emit a permutation, @var{in0} and @var{in1} are the source vectors of mode\n\
1903	@var{op_mode} and @var{out} is the destination vector of mode @var{mode}.\n\
1904	@var{in1} is the same as @var{in0} if @var{sel} describes a permutation on one\n\
1905	vector instead of two.\n\
1906	\n\
1907	Return true if the operation is possible, emitting instructions for it\n\
1908	if rtxes are provided.\n\
1909	\n\
1910	@cindex @code{vec_perm@var{m}} instruction pattern\n\
1911	If the hook returns false for a mode with multibyte elements, GCC will\n\
1912	try the equivalent byte operation. If that also fails, it will try forcing\n\
1913	the selector into a register and using the @var{vec_perm@var{mode}}\n\
1914	instruction pattern. There is no need for the hook to handle these two\n\
1915	implementation approaches itself.",
1916	bool, (machine_mode mode, machine_mode op_mode, rtx output, rtx in0, rtx in1,
1917	const vec_perm_indices &sel),
1918	NULL)
1919
1920	/* Return true if the target supports misaligned store/load of a
1921	specific factor denoted in the third parameter. The last parameter
1922	is true if the access is defined in a packed struct. */
1923	DEFHOOK
1924	(support_vector_misalignment,
1925	"This hook should return true if the target supports misaligned vector\n\
1926	store/load of a specific factor denoted in the @var{misalignment}\n\
1927	parameter. The vector store/load should be of machine mode @var{mode} and\n\
1928	the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1929	parameter is true if the memory access is defined in a packed struct.",
1930	bool,
1931	(machine_mode mode, const_tree type, int misalignment, bool is_packed),
1932	default_builtin_support_vector_misalignment)
1933
1934	/* Returns the preferred mode for SIMD operations for the specified
1935	scalar mode. */
1936	DEFHOOK
1937	(preferred_simd_mode,
1938	"This hook should return the preferred mode for vectorizing scalar\n\
1939	mode @var{mode}. The default is\n\
1940	equal to @code{word_mode}, because the vectorizer can do some\n\
1941	transformations even in absence of specialized @acronym{SIMD} hardware.",
1942	machine_mode,
1943	(scalar_mode mode),
1944	default_preferred_simd_mode)
1945
1946	/* Returns the preferred mode for splitting SIMD reductions to. */
1947	DEFHOOK
1948	(split_reduction,
1949	"This hook should return the preferred mode to split the final reduction\n\
1950	step on @var{mode} to. The reduction is then carried out reducing upper\n\
1951	against lower halves of vectors recursively until the specified mode is\n\
1952	reached. The default is @var{mode} which means no splitting.",
1953	machine_mode,
1954	(machine_mode),
1955	default_split_reduction)
1956
1957	/* Returns a mask of vector sizes to iterate over when auto-vectorizing
1958	after processing the preferred one derived from preferred_simd_mode. */
1959	DEFHOOK
1960	(autovectorize_vector_modes,
1961	"If using the mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}\n\
1962	is not the only approach worth considering, this hook should add one mode to\n\
1963	@var{modes} for each useful alternative approach. These modes are then\n\
1964	passed to @code{TARGET_VECTORIZE_RELATED_MODE} to obtain the vector mode\n\
1965	for a given element mode.\n\
1966	\n\
1967	The modes returned in @var{modes} should use the smallest element mode\n\
1968	possible for the vectorization approach that they represent, preferring\n\
1969	integer modes over floating-poing modes in the event of a tie. The first\n\
1970	mode should be the @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} for its\n\
1971	element mode.\n\
1972	\n\
1973	If @var{all} is true, add suitable vector modes even when they are generally\n\
1974	not expected to be worthwhile.\n\
1975	\n\
1976	The hook returns a bitmask of flags that control how the modes in\n\
1977	@var{modes} are used. The flags are:\n\
1978	@table @code\n\
1979	@item VECT_COMPARE_COSTS\n\
1980	Tells the loop vectorizer to try all the provided modes and pick the one\n\
1981	with the lowest cost. By default the vectorizer will choose the first\n\
1982	mode that works.\n\
1983	@end table\n\
1984	\n\
1985	The hook does not need to do anything if the vector returned by\n\
1986	@code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} is the only one relevant\n\
1987	for autovectorization. The default implementation adds no modes and\n\
1988	returns 0.",
1989	unsigned int,
1990	(vector_modes *modes, bool all),
1991	default_autovectorize_vector_modes)
1992
1993	DEFHOOK
1994	(related_mode,
1995	"If a piece of code is using vector mode @var{vector_mode} and also wants\n\
1996	to operate on elements of mode @var{element_mode}, return the vector mode\n\
1997	it should use for those elements. If @var{nunits} is nonzero, ensure that\n\
1998	the mode has exactly @var{nunits} elements, otherwise pick whichever vector\n\
1999	size pairs the most naturally with @var{vector_mode}. Return an empty\n\
2000	@code{opt_machine_mode} if there is no supported vector mode with the\n\
2001	required properties.\n\
2002	\n\
2003	There is no prescribed way of handling the case in which @var{nunits}\n\
2004	is zero. One common choice is to pick a vector mode with the same size\n\
2005	as @var{vector_mode}; this is the natural choice if the target has a\n\
2006	fixed vector size. Another option is to choose a vector mode with the\n\
2007	same number of elements as @var{vector_mode}; this is the natural choice\n\
2008	if the target has a fixed number of elements. Alternatively, the hook\n\
2009	might choose a middle ground, such as trying to keep the number of\n\
2010	elements as similar as possible while applying maximum and minimum\n\
2011	vector sizes.\n\
2012	\n\
2013	The default implementation uses @code{mode_for_vector} to find the\n\
2014	requested mode, returning a mode with the same size as @var{vector_mode}\n\
2015	when @var{nunits} is zero. This is the correct behavior for most targets.",
2016	opt_machine_mode,
2017	(machine_mode vector_mode, scalar_mode element_mode, poly_uint64 nunits),
2018	default_vectorize_related_mode)
2019
2020	/* Function to get a target mode for a vector mask. */
2021	DEFHOOK
2022	(get_mask_mode,
2023	"Return the mode to use for a vector mask that holds one boolean\n\
2024	result for each element of vector mode @var{mode}. The returned mask mode\n\
2025	can be a vector of integers (class @code{MODE_VECTOR_INT}), a vector of\n\
2026	booleans (class @code{MODE_VECTOR_BOOL}) or a scalar integer (class\n\
2027	@code{MODE_INT}). Return an empty @code{opt_machine_mode} if no such\n\
2028	mask mode exists.\n\
2029	\n\
2030	The default implementation returns a @code{MODE_VECTOR_INT} with the\n\
2031	same size and number of elements as @var{mode}, if such a mode exists.",
2032	opt_machine_mode,
2033	(machine_mode mode),
2034	default_get_mask_mode)
2035
2036	/* Function to say whether a masked operation is expensive when the
2037	mask is all zeros. */
2038	DEFHOOK
2039	(empty_mask_is_expensive,
2040	"This hook returns true if masked internal function @var{ifn} (really of\n\
2041	type @code{internal_fn}) should be considered expensive when the mask is\n\
2042	all zeros. GCC can then try to branch around the instruction instead.",
2043	bool,
2044	(unsigned ifn),
2045	default_empty_mask_is_expensive)
2046
2047	/* Target builtin that implements vector gather operation. */
2048	DEFHOOK
2049	(builtin_gather,
2050	"Target builtin that implements vector gather operation. @var{mem_vectype}\n\
2051	is the vector type of the load and @var{index_type} is scalar type of\n\
2052	the index, scaled by @var{scale}.\n\
2053	The default is @code{NULL_TREE} which means to not vectorize gather\n\
2054	loads.",
2055	tree,
2056	(const_tree mem_vectype, const_tree index_type, int scale),
2057	NULL)
2058
2059	/* Target builtin that implements vector scatter operation. */
2060	DEFHOOK
2061	(builtin_scatter,
2062	"Target builtin that implements vector scatter operation. @var{vectype}\n\
2063	is the vector type of the store and @var{index_type} is scalar type of\n\
2064	the index, scaled by @var{scale}.\n\
2065	The default is @code{NULL_TREE} which means to not vectorize scatter\n\
2066	stores.",
2067	tree,
2068	(const_tree vectype, const_tree index_type, int scale),
2069	NULL)
2070
2071	/* Target function to initialize the cost model for a loop or block. */
2072	DEFHOOK
2073	(create_costs,
2074	"This hook should initialize target-specific data structures in preparation\n\
2075	for modeling the costs of vectorizing a loop or basic block. The default\n\
2076	allocates three unsigned integers for accumulating costs for the prologue,\n\
2077	body, and epilogue of the loop or basic block. If @var{loop_info} is\n\
2078	non-NULL, it identifies the loop being vectorized; otherwise a single block\n\
2079	is being vectorized. If @var{costing_for_scalar} is true, it indicates the\n\
2080	current cost model is for the scalar version of a loop or block; otherwise\n\
2081	it is for the vector version.",
2082	class vector_costs *,
2083	(vec_info *vinfo, bool costing_for_scalar),
2084	default_vectorize_create_costs)
2085
2086	HOOK_VECTOR_END (vectorize)
2087
2088	#undef HOOK_PREFIX
2089	#define HOOK_PREFIX "TARGET_"
2090
2091	DEFHOOK
2092	(preferred_else_value,
2093	"This hook returns the target's preferred final argument for a call\n\
2094	to conditional internal function @var{ifn} (really of type\n\
2095	@code{internal_fn}). @var{type} specifies the return type of the\n\
2096	function and @var{ops} are the operands to the conditional operation,\n\
2097	of which there are @var{nops}.\n\
2098	\n\
2099	For example, if @var{ifn} is @code{IFN_COND_ADD}, the hook returns\n\
2100	a value of type @var{type} that should be used when @samp{@var{ops}[0]}\n\
2101	and @samp{@var{ops}[1]} are conditionally added together.\n\
2102	\n\
2103	This hook is only relevant if the target supports conditional patterns\n\
2104	like @code{cond_add@var{m}}. The default implementation returns a zero\n\
2105	constant of type @var{type}.",
2106	tree,
2107	(unsigned ifn, tree type, unsigned nops, tree *ops),
2108	default_preferred_else_value)
2109
2110	DEFHOOK
2111	(record_offload_symbol,
2112	"Used when offloaded functions are seen in the compilation unit and no named\n\
2113	sections are available. It is called once for each symbol that must be\n\
2114	recorded in the offload function and variable table.",
2115	void, (tree),
2116	hook_void_tree)
2117
2118	DEFHOOKPOD
2119	(absolute_biggest_alignment,
2120	"If defined, this target hook specifies the absolute biggest alignment\n\
2121	that a type or variable can have on this machine, otherwise,\n\
2122	@code{BIGGEST_ALIGNMENT} is used.",
2123	HOST_WIDE_INT, BIGGEST_ALIGNMENT)
2124
2125	/* Allow target specific overriding of option settings after options have
2126	been changed by an attribute or pragma or when it is reset at the
2127	end of the code affected by an attribute or pragma. */
2128	DEFHOOK
2129	(override_options_after_change,
2130	"This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
2131	but is called when the optimize level is changed via an attribute or\n\
2132	pragma or when it is reset at the end of the code affected by the\n\
2133	attribute or pragma. It is not called at the beginning of compilation\n\
2134	when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
2135	actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
2136	@code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
2137	void, (void),
2138	hook_void_void)
2139
2140	DEFHOOK
2141	(offload_options,
2142	"Used when writing out the list of options into an LTO file. It should\n\
2143	translate any relevant target-specific options (such as the ABI in use)\n\
2144	into one of the @option{-foffload} options that exist as a common interface\n\
2145	to express such options. It should return a string containing these options,\n\
2146	separated by spaces, which the caller will free.\n",
2147	char *, (void), hook_charptr_void_null)
2148
2149	DEFHOOK_UNDOC
2150	(eh_return_filter_mode,
2151	"Return machine mode for filter value.",
2152	scalar_int_mode, (void),
2153	default_eh_return_filter_mode)
2154
2155	/* Return machine mode for libgcc expanded cmp instructions. */
2156	DEFHOOK
2157	(libgcc_cmp_return_mode,
2158	"This target hook should return the mode to be used for the return value\n\
2159	of compare instructions expanded to libgcc calls. If not defined\n\
2160	@code{word_mode} is returned which is the right choice for a majority of\n\
2161	targets.",
2162	scalar_int_mode, (void),
2163	default_libgcc_cmp_return_mode)
2164
2165	/* Return machine mode for libgcc expanded shift instructions. */
2166	DEFHOOK
2167	(libgcc_shift_count_mode,
2168	"This target hook should return the mode to be used for the shift count operand\n\
2169	of shift instructions expanded to libgcc calls. If not defined\n\
2170	@code{word_mode} is returned which is the right choice for a majority of\n\
2171	targets.",
2172	scalar_int_mode, (void),
2173	default_libgcc_shift_count_mode)
2174
2175	/* Return machine mode to be used for _Unwind_Word type. */
2176	DEFHOOK
2177	(unwind_word_mode,
2178	"Return machine mode to be used for @code{_Unwind_Word} type.\n\
2179	The default is to use @code{word_mode}.",
2180	scalar_int_mode, (void),
2181	default_unwind_word_mode)
2182
2183	/* Given two decls, merge their attributes and return the result. */
2184	DEFHOOK
2185	(merge_decl_attributes,
2186	"Define this target hook if the merging of decl attributes needs special\n\
2187	handling. If defined, the result is a list of the combined\n\
2188	@code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2189	@var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2190	when this is needed are when one attribute overrides another, or when an\n\
2191	attribute is nullified by a subsequent definition. This function may\n\
2192	call @code{merge_attributes} to handle machine-independent merging.\n\
2193	\n\
2194	@findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2195	If the only target-specific handling you require is @samp{dllimport}\n\
2196	for Microsoft Windows targets, you should define the macro\n\
2197	@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2198	will then define a function called\n\
2199	@code{merge_dllimport_decl_attributes} which can then be defined as\n\
2200	the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2201	add @code{handle_dll_attribute} in the attribute table for your port\n\
2202	to perform initial processing of the @samp{dllimport} and\n\
2203	@samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2204	@file{i386/i386.cc}, for example.",
2205	tree, (tree olddecl, tree newdecl),
2206	merge_decl_attributes)
2207
2208	/* Given two types, merge their attributes and return the result. */
2209	DEFHOOK
2210	(merge_type_attributes,
2211	"Define this target hook if the merging of type attributes needs special\n\
2212	handling. If defined, the result is a list of the combined\n\
2213	@code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2214	that @code{comptypes} has already been called and returned 1. This\n\
2215	function may call @code{merge_attributes} to handle machine-independent\n\
2216	merging.",
2217	tree, (tree type1, tree type2),
2218	merge_type_attributes)
2219
2220	/* Table of machine attributes and functions to handle them.
2221	Ignored if empty. */
2222	DEFHOOKPOD
2223	(attribute_table,
2224	"If defined, this target hook provides an array of\n\
2225	@samp{scoped_attribute_spec}s (defined in @file{attribs.h}) that specify the\n\
2226	machine-specific attributes for this target. The information includes some\n\
2227	of the restrictions on the entities to which these attributes are applied\n\
2228	and the arguments that the attributes take.\n\
2229	\n\
2230	In C and C++, these attributes are associated with two syntaxes:\n\
2231	the traditional GNU @code{__attribute__} syntax and the standard\n\
2232	@samp{[[]]} syntax. Attributes that support the GNU syntax must be\n\
2233	placed in the @code{gnu} namespace. Such attributes can then also be\n\
2234	written @samp{[[gnu::@dots{}]]}. Attributes that use only the standard\n\
2235	syntax should be placed in whichever namespace the attribute specification\n\
2236	requires. For example, a target might choose to support vendor-specific\n\
2237	@samp{[[]]} attributes that the vendor places in their own namespace.\n\
2238	\n\
2239	Targets that only define attributes in the @code{gnu} namespace\n\
2240	can uase the following shorthand to define the table:\n\
2241	\n\
2242	@smallexample\n\
2243	TARGET_GNU_ATTRIBUTES (@var{cpu_attribute_table}, @{\n\
2244	@{ \"@var{attribute1}\", @dots{} @},\n\
2245	@{ \"@var{attribute2}\", @dots{} @},\n\
2246	@dots{},\n\
2247	@{ \"@var{attributen}\", @dots{} @},\n\
2248	@});\n\
2249	@end smallexample",
2250	array_slice<const struct scoped_attribute_specs *const>,)
2251
2252	/* Return true iff attribute NAME expects a plain identifier as its first
2253	argument. */
2254	DEFHOOK
2255	(attribute_takes_identifier_p,
2256	"If defined, this target hook is a function which returns true if the\n\
2257	machine-specific attribute named @var{name} expects an identifier\n\
2258	given as its first argument to be passed on as a plain identifier, not\n\
2259	subjected to name lookup. If this is not defined, the default is\n\
2260	false for all machine-specific attributes.",
2261	bool, (const_tree name),
2262	hook_bool_const_tree_false)
2263
2264	/* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2265	one if they are compatible and two if they are nearly compatible
2266	(which causes a warning to be generated). */
2267	DEFHOOK
2268	(comp_type_attributes,
2269	"If defined, this target hook is a function which returns zero if the attributes on\n\
2270	@var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2271	and two if they are nearly compatible (which causes a warning to be\n\
2272	generated). If this is not defined, machine-specific attributes are\n\
2273	supposed always to be compatible.",
2274	int, (const_tree type1, const_tree type2),
2275	hook_int_const_tree_const_tree_1)
2276
2277	/* Assign default attributes to the newly defined TYPE. */
2278	DEFHOOK
2279	(set_default_type_attributes,
2280	"If defined, this target hook is a function which assigns default attributes to\n\
2281	the newly defined @var{type}.",
2282	void, (tree type),
2283	hook_void_tree)
2284
2285	/* Insert attributes on the newly created DECL. */
2286	DEFHOOK
2287	(insert_attributes,
2288	"Define this target hook if you want to be able to add attributes to a decl\n\
2289	when it is being created. This is normally useful for back ends which\n\
2290	wish to implement a pragma by using the attributes which correspond to\n\
2291	the pragma's effect. The @var{node} argument is the decl which is being\n\
2292	created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2293	for this decl. The list itself should not be modified, since it may be\n\
2294	shared with other decls, but attributes may be chained on the head of\n\
2295	the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2296	attributes, or a copy of the list may be made if further changes are\n\
2297	needed.",
2298	void, (tree node, tree *attr_ptr),
2299	hook_void_tree_treeptr)
2300
2301	/* Perform additional target-specific processing of generic attributes. */
2302	DEFHOOK
2303	(handle_generic_attribute,
2304	"Define this target hook if you want to be able to perform additional\n\
2305	target-specific processing of an attribute which is handled generically\n\
2306	by a front end. The arguments are the same as those which are passed to\n\
2307	attribute handlers. So far this only affects the @var{noinit} and\n\
2308	@var{section} attribute.",
2309	tree, (tree *node, tree name, tree args, int flags, bool *no_add_attrs),
2310	hook_tree_treeptr_tree_tree_int_boolptr_null)
2311
2312	/* Return true if FNDECL (which has at least one machine attribute)
2313	can be inlined despite its machine attributes, false otherwise. */
2314	DEFHOOK
2315	(function_attribute_inlinable_p,
2316	"@cindex inlining\n\
2317	This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2318	into the current function, despite its having target-specific\n\
2319	attributes, @code{false} otherwise. By default, if a function has a\n\
2320	target specific attribute attached to it, it will not be inlined.",
2321	bool, (const_tree fndecl),
2322	hook_bool_const_tree_false)
2323
2324	/* Return true if bitfields in RECORD_TYPE should follow the
2325	Microsoft Visual C++ bitfield layout rules. */
2326	DEFHOOK
2327	(ms_bitfield_layout_p,
2328	"This target hook returns @code{true} if bit-fields in the given\n\
2329	@var{record_type} are to be laid out following the rules of Microsoft\n\
2330	Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2331	unit with the previous bit-field if their underlying types have\n\
2332	different sizes, and the bit-field will be aligned to the highest\n\
2333	alignment of the underlying types of itself and of the previous\n\
2334	bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2335	the whole enclosing structure, even if it is unnamed; except that\n\
2336	(iii) a zero-sized bit-field will be disregarded unless it follows\n\
2337	another bit-field of nonzero size. If this hook returns @code{true},\n\
2338	other macros that control bit-field layout are ignored.\n\
2339	\n\
2340	When a bit-field is inserted into a packed record, the whole size\n\
2341	of the underlying type is used by one or more same-size adjacent\n\
2342	bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2343	and any additional adjacent long bit-fields are packed into the same\n\
2344	chunk of 32 bits. However, if the size changes, a new field of that\n\
2345	size is allocated). In an unpacked record, this is the same as using\n\
2346	alignment, but not equivalent when packing.\n\
2347	\n\
2348	If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2349	the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2350	used on a single field when MS bit-fields are in use, it will take\n\
2351	precedence for that field, but the alignment of the rest of the structure\n\
2352	may affect its placement.",
2353	bool, (const_tree record_type),
2354	hook_bool_const_tree_false)
2355
2356	/* For now this is only an interface to WORDS_BIG_ENDIAN for
2357	target-independent code like the front ends, need performance testing
2358	before switching completely to the target hook. */
2359	DEFHOOK_UNDOC
2360	(words_big_endian,
2361	"",
2362	bool, (void),
2363	targhook_words_big_endian)
2364
2365	/* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2366	DEFHOOK_UNDOC
2367	(float_words_big_endian,
2368	"",
2369	bool, (void),
2370	targhook_float_words_big_endian)
2371
2372	DEFHOOK
2373	(float_exceptions_rounding_supported_p,
2374	"Returns true if the target supports IEEE 754 floating-point exceptions\n\
2375	and rounding modes, false otherwise. This is intended to relate to the\n\
2376	@code{float} and @code{double} types, but not necessarily @code{long double}.\n\
2377	By default, returns true if the @code{adddf3} instruction pattern is\n\
2378	available and false otherwise, on the assumption that hardware floating\n\
2379	point supports exceptions and rounding modes but software floating point\n\
2380	does not.",
2381	bool, (void),
2382	default_float_exceptions_rounding_supported_p)
2383
2384	/* True if the target supports decimal floating point. */
2385	DEFHOOK
2386	(decimal_float_supported_p,
2387	"Returns true if the target supports decimal floating point.",
2388	bool, (void),
2389	default_decimal_float_supported_p)
2390
2391	/* True if the target supports fixed-point. */
2392	DEFHOOK
2393	(fixed_point_supported_p,
2394	"Returns true if the target supports fixed-point arithmetic.",
2395	bool, (void),
2396	default_fixed_point_supported_p)
2397
2398	/* Return true if anonymous bitfields affect structure alignment. */
2399	DEFHOOK
2400	(align_anon_bitfield,
2401	"When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2402	whether unnamed bitfields affect the alignment of the containing\n\
2403	structure. The hook should return true if the structure should inherit\n\
2404	the alignment requirements of an unnamed bitfield's type.",
2405	bool, (void),
2406	hook_bool_void_false)
2407
2408	/* Return true if volatile bitfields should use the narrowest type possible.
2409	Return false if they should use the container type. */
2410	DEFHOOK
2411	(narrow_volatile_bitfield,
2412	"This target hook should return @code{true} if accesses to volatile bitfields\n\
2413	should use the narrowest mode possible. It should return @code{false} if\n\
2414	these accesses should use the bitfield container type.\n\
2415	\n\
2416	The default is @code{false}.",
2417	bool, (void),
2418	hook_bool_void_false)
2419
2420	/* Set up target-specific built-in functions. */
2421	DEFHOOK
2422	(init_builtins,
2423	"Define this hook if you have any machine-specific built-in functions\n\
2424	that need to be defined. It should be a function that performs the\n\
2425	necessary setup.\n\
2426	\n\
2427	Machine specific built-in functions can be useful to expand special machine\n\
2428	instructions that would otherwise not normally be generated because\n\
2429	they have no equivalent in the source language (for example, SIMD vector\n\
2430	instructions or prefetch instructions).\n\
2431	\n\
2432	To create a built-in function, call the function\n\
2433	@code{lang_hooks.builtin_function}\n\
2434	which is defined by the language front end. You can use any type nodes set\n\
2435	up by @code{build_common_tree_nodes};\n\
2436	only language front ends that use those two functions will call\n\
2437	@samp{TARGET_INIT_BUILTINS}.",
2438	void, (void),
2439	hook_void_void)
2440
2441	/* Initialize (if INITIALIZE_P is true) and return the target-specific
2442	built-in function decl for CODE.
2443	Return NULL if that is not possible. Return error_mark_node if CODE
2444	is outside of the range of valid target builtin function codes. */
2445	DEFHOOK
2446	(builtin_decl,
2447	"Define this hook if you have any machine-specific built-in functions\n\
2448	that need to be defined. It should be a function that returns the\n\
2449	builtin function declaration for the builtin function code @var{code}.\n\
2450	If there is no such builtin and it cannot be initialized at this time\n\
2451	if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2452	If @var{code} is out of range the function should return\n\
2453	@code{error_mark_node}.",
2454	tree, (unsigned code, bool initialize_p), NULL)
2455
2456	/* Expand a target-specific builtin. */
2457	DEFHOOK
2458	(expand_builtin,
2459	"\n\
2460	Expand a call to a machine specific built-in function that was set up by\n\
2461	@samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2462	function call; the result should go to @var{target} if that is\n\
2463	convenient, and have mode @var{mode} if that is convenient.\n\
2464	@var{subtarget} may be used as the target for computing one of\n\
2465	@var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2466	ignored. This function should return the result of the call to the\n\
2467	built-in function.",
2468	rtx,
2469	(tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2470	default_expand_builtin)
2471
2472	/* Select a replacement for a target-specific builtin. This is done
2473	*before* regular type checking, and so allows the target to
2474	implement a crude form of function overloading. The result is a
2475	complete expression that implements the operation. PARAMS really
2476	has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2477	DEFHOOK
2478	(resolve_overloaded_builtin,
2479	"Select a replacement for a machine specific built-in function that\n\
2480	was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2481	@emph{before} regular type checking, and so allows the target to\n\
2482	implement a crude form of function overloading. @var{fndecl} is the\n\
2483	declaration of the built-in function. @var{arglist} is the list of\n\
2484	arguments passed to the built-in function. The result is a\n\
2485	complete expression that implements the operation, usually\n\
2486	another @code{CALL_EXPR}.\n\
2487	@var{arglist} really has type @samp{VEC(tree,gc)*}",
2488	tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2489
2490	DEFHOOK
2491	(check_builtin_call,
2492	"Perform semantic checking on a call to a machine-specific built-in\n\
2493	function after its arguments have been constrained to the function\n\
2494	signature. Return true if the call is valid, otherwise report an error\n\
2495	and return false.\n\
2496	\n\
2497	This hook is called after @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}.\n\
2498	The call was originally to built-in function @var{orig_fndecl},\n\
2499	but after the optional @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}\n\
2500	step is now to built-in function @var{fndecl}. @var{loc} is the\n\
2501	location of the call and @var{args} is an array of function arguments,\n\
2502	of which there are @var{nargs}. @var{arg_loc} specifies the location\n\
2503	of each argument.",
2504	bool, (location_t loc, vec<location_t> arg_loc, tree fndecl,
2505	tree orig_fndecl, unsigned int nargs, tree *args),
2506	NULL)
2507
2508	/* Fold a target-specific builtin to a tree valid for both GIMPLE
2509	and GENERIC. */
2510	DEFHOOK
2511	(fold_builtin,
2512	"Fold a call to a machine specific built-in function that was set up by\n\
2513	@samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2514	built-in function. @var{n_args} is the number of arguments passed to\n\
2515	the function; the arguments themselves are pointed to by @var{argp}.\n\
2516	The result is another tree, valid for both GIMPLE and GENERIC,\n\
2517	containing a simplified expression for the call's result. If\n\
2518	@var{ignore} is true the value will be ignored.",
2519	tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2520	hook_tree_tree_int_treep_bool_null)
2521
2522	/* Fold a target-specific builtin to a valid GIMPLE tree. */
2523	DEFHOOK
2524	(gimple_fold_builtin,
2525	"Fold a call to a machine specific built-in function that was set up\n\
2526	by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2527	statement holding the function call. Returns true if any change\n\
2528	was made to the GIMPLE stream.",
2529	bool, (gimple_stmt_iterator *gsi),
2530	hook_bool_gsiptr_false)
2531
2532	/* Target hook is used to compare the target attributes in two functions to
2533	determine which function's features get higher priority. This is used
2534	during function multi-versioning to figure out the order in which two
2535	versions must be dispatched. A function version with a higher priority
2536	is checked for dispatching earlier. DECL1 and DECL2 are
2537	the two function decls that will be compared. It returns positive value
2538	if DECL1 is higher priority, negative value if DECL2 is higher priority
2539	and 0 if they are the same. */
2540	DEFHOOK
2541	(compare_version_priority,
2542	"This hook is used to compare the target attributes in two functions to\n\
2543	determine which function's features get higher priority. This is used\n\
2544	during function multi-versioning to figure out the order in which two\n\
2545	versions must be dispatched. A function version with a higher priority\n\
2546	is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2547	the two function decls that will be compared.",
2548	int, (tree decl1, tree decl2), NULL)
2549
2550	/* Target hook is used to generate the dispatcher logic to invoke the right
2551	function version at run-time for a given set of function versions.
2552	ARG points to the callgraph node of the dispatcher function whose body
2553	must be generated. */
2554	DEFHOOK
2555	(generate_version_dispatcher_body,
2556	"This hook is used to generate the dispatcher logic to invoke the right\n\
2557	function version at run-time for a given set of function versions.\n\
2558	@var{arg} points to the callgraph node of the dispatcher function whose\n\
2559	body must be generated.",
2560	tree, (void *arg), NULL)
2561
2562	/* Target hook is used to get the dispatcher function for a set of function
2563	versions. The dispatcher function is called to invoke the right function
2564	version at run-time. DECL is one version from a set of semantically
2565	identical versions. */
2566	DEFHOOK
2567	(get_function_versions_dispatcher,
2568	"This hook is used to get the dispatcher function for a set of function\n\
2569	versions. The dispatcher function is called to invoke the right function\n\
2570	version at run-time. @var{decl} is one version from a set of semantically\n\
2571	identical versions.",
2572	tree, (void *decl), NULL)
2573
2574	/* Returns a code for a target-specific builtin that implements
2575	reciprocal of a target-specific function, or NULL_TREE if not available. */
2576	DEFHOOK
2577	(builtin_reciprocal,
2578	"This hook should return the DECL of a function that implements the\n\
2579	reciprocal of the machine-specific builtin function @var{fndecl}, or\n\
2580	@code{NULL_TREE} if such a function is not available.",
2581	tree, (tree fndecl),
2582	default_builtin_reciprocal)
2583
2584	/* For a vendor-specific TYPE, return a pointer to a statically-allocated
2585	string containing the C++ mangling for TYPE. In all other cases, return
2586	NULL. */
2587	DEFHOOK
2588	(mangle_type,
2589	"If your target defines any fundamental types, or any types your target\n\
2590	uses should be mangled differently from the default, define this hook\n\
2591	to return the appropriate encoding for these types as part of a C++\n\
2592	mangled name. The @var{type} argument is the tree structure representing\n\
2593	the type to be mangled. The hook may be applied to trees which are\n\
2594	not target-specific fundamental types; it should return @code{NULL}\n\
2595	for all such types, as well as arguments it does not recognize. If the\n\
2596	return value is not @code{NULL}, it must point to a statically-allocated\n\
2597	string constant.\n\
2598	\n\
2599	Target-specific fundamental types might be new fundamental types or\n\
2600	qualified versions of ordinary fundamental types. Encode new\n\
2601	fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2602	is the name used for the type in source code, and @var{n} is the\n\
2603	length of @var{name} in decimal. Encode qualified versions of\n\
2604	ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2605	@var{name} is the name used for the type qualifier in source code,\n\
2606	@var{n} is the length of @var{name} as above, and @var{code} is the\n\
2607	code used to represent the unqualified version of this type. (See\n\
2608	@code{write_builtin_type} in @file{cp/mangle.cc} for the list of\n\
2609	codes.) In both cases the spaces are for clarity; do not include any\n\
2610	spaces in your string.\n\
2611	\n\
2612	This hook is applied to types prior to typedef resolution. If the mangled\n\
2613	name for a particular type depends only on that type's main variant, you\n\
2614	can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2615	before mangling.\n\
2616	\n\
2617	The default version of this hook always returns @code{NULL}, which is\n\
2618	appropriate for a target that does not define any new fundamental\n\
2619	types.",
2620	const char *, (const_tree type),
2621	hook_constcharptr_const_tree_null)
2622
2623	/* Temporarily add conditional target specific types for the purpose of
2624	emitting C++ fundamental type tinfos. */
2625	DEFHOOK
2626	(emit_support_tinfos,
2627	"If your target defines any fundamental types which depend on ISA flags,\n\
2628	they might need C++ tinfo symbols in libsupc++/libstdc++ regardless of\n\
2629	ISA flags the library is compiled with.\n\
2630	This hook allows creating tinfo symbols even for those cases, by temporarily\n\
2631	creating each corresponding fundamental type trees, calling the\n\
2632	@var{callback} function on it and setting the type back to @code{nullptr}.",
2633	void, (emit_support_tinfos_callback callback),
2634	default_emit_support_tinfos)
2635
2636	/* Make any adjustments to libfunc names needed for this target. */
2637	DEFHOOK
2638	(init_libfuncs,
2639	"This hook should declare additional library routines or rename\n\
2640	existing ones, using the functions @code{set_optab_libfunc} and\n\
2641	@code{init_one_libfunc} defined in @file{optabs.cc}.\n\
2642	@code{init_optabs} calls this macro after initializing all the normal\n\
2643	library routines.\n\
2644	\n\
2645	The default is to do nothing. Most ports don't need to define this hook.",
2646	void, (void),
2647	hook_void_void)
2648
2649	/* Add a __gnu_ prefix to library functions rather than just __. */
2650	DEFHOOKPOD
2651	(libfunc_gnu_prefix,
2652	"If false (the default), internal library routines start with two\n\
2653	underscores. If set to true, these routines start with @code{__gnu_}\n\
2654	instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2655	currently only affects functions defined in @file{libgcc2.c}. If this\n\
2656	is set to true, the @file{tm.h} file must also\n\
2657	@code{#define LIBGCC2_GNU_PREFIX}.",
2658	bool, false)
2659
2660	/* Given a decl, a section name, and whether the decl initializer
2661	has relocs, choose attributes for the section. */
2662	/* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2663	DEFHOOK
2664	(section_type_flags,
2665	"Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2666	based on a variable or function decl, a section name, and whether or not the\n\
2667	declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2668	null, in which case read-write data should be assumed.\n\
2669	\n\
2670	The default version of this function handles choosing code vs data,\n\
2671	read-only vs read-write data, and @code{flag_pic}. You should only\n\
2672	need to override this if your target has special flags that might be\n\
2673	set via @code{__attribute__}.",
2674	unsigned int, (tree decl, const char *name, int reloc),
2675	default_section_type_flags)
2676
2677	DEFHOOK
2678	(libc_has_function,
2679	"This hook determines whether a function from a class of functions\n\
2680	@var{fn_class} is present in the target C library. If @var{type} is NULL,\n\
2681	the caller asks for support for all standard (float, double, long double)\n\
2682	types. If @var{type} is non-NULL, the caller asks for support for a\n\
2683	specific type.",
2684	bool, (enum function_class fn_class, tree type),
2685	default_libc_has_function)
2686
2687	DEFHOOK
2688	(libc_has_fast_function,
2689	"This hook determines whether a function from a class of functions\n\
2690	@code{(enum function_class)}@var{fcode} has a fast implementation.",
2691	bool, (int fcode),
2692	default_libc_has_fast_function)
2693
2694	DEFHOOK
2695	(fortify_source_default_level,
2696	"This hook determines what value _FORTIFY_SOURCE will be set to when using\n\
2697	the command-line option -fhardened.",
2698	unsigned, (void),
2699	default_fortify_source_default_level)
2700
2701	DEFHOOK
2702	(libm_function_max_error,
2703	"This hook determines expected maximum errors for math functions measured\n\
2704	in ulps (units of the last place). 0 means 0.5ulps precision (correctly\n\
2705	rounded). ~0U means unknown errors. The @code{combined_fn} @var{cfn}\n\
2706	argument should identify just which math built-in function it is rather than\n\
2707	its variant, @var{mode} the variant in terms of floating-point machine mode.\n\
2708	The hook should also take into account @code{flag_rounding_math} whether it\n\
2709	is maximum error just in default rounding mode, or in all possible rounding\n\
2710	modes. @var{boundary_p} is @code{true} for maximum errors on intrinsic math\n\
2711	boundaries of functions rather than errors inside of the usual result ranges\n\
2712	of the functions. E.g.@ the sin/cos function finite result is in between\n\
2713	-1.0 and 1.0 inclusive, with @var{boundary_p} true the function returns how\n\
2714	many ulps below or above those boundaries result could be.",
2715	unsigned, (unsigned cfn, machine_mode mode, bool boundary_p),
2716	default_libm_function_max_error)
2717
2718	/* True if new jumps cannot be created, to replace existing ones or
2719	not, at the current point in the compilation. */
2720	DEFHOOK
2721	(cannot_modify_jumps_p,
2722	"This target hook returns @code{true} past the point in which new jump\n\
2723	instructions could be created. On machines that require a register for\n\
2724	every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2725	reload, so this target hook should be defined to a function such as:\n\
2726	\n\
2727	@smallexample\n\
2728	static bool\n\
2729	cannot_modify_jumps_past_reload_p ()\n\
2730	@{\n\
2731	return (reload_completed || reload_in_progress);\n\
2732	@}\n\
2733	@end smallexample",
2734	bool, (void),
2735	hook_bool_void_false)
2736
2737	/* True if FOLLOWER may be modified to follow FOLLOWEE. */
2738	DEFHOOK
2739	(can_follow_jump,
2740	"FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\n\
2741	return true if FOLLOWER may be modified to follow FOLLOWEE;\n\
2742	false, if it can't.\n\
2743	For example, on some targets, certain kinds of branches can't be made to\n\
2744	follow through a hot/cold partitioning.",
2745	bool, (const rtx_insn *follower, const rtx_insn *followee),
2746	hook_bool_const_rtx_insn_const_rtx_insn_true)
2747
2748	/* Return true if the target supports conditional execution. */
2749	DEFHOOK
2750	(have_conditional_execution,
2751	"This target hook returns true if the target supports conditional execution.\n\
2752	This target hook is required only when the target has several different\n\
2753	modes and they have different conditional execution capability, such as ARM.",
2754	bool, (void),
2755	default_have_conditional_execution)
2756
2757	DEFHOOK
2758	(gen_ccmp_first,
2759	"This function prepares to emit a comparison insn for the first compare in a\n\
2760	sequence of conditional comparisions. It returns an appropriate comparison\n\
2761	with @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2762	The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2763	insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2764	compares in the conditional comparision are generated without error.\n\
2765	@var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2766	rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx_code code, tree op0, tree op1),
2767	NULL)
2768
2769	DEFHOOK
2770	(gen_ccmp_next,
2771	"This function prepares to emit a conditional comparison within a sequence\n\
2772	of conditional comparisons. It returns an appropriate comparison with\n\
2773	@code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2774	The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2775	insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2776	compares in the conditional comparision are generated without error. The\n\
2777	@var{prev} expression is the result of a prior call to @code{gen_ccmp_first}\n\
2778	or @code{gen_ccmp_next}. It may return @code{NULL} if the combination of\n\
2779	@var{prev} and this comparison is not supported, otherwise the result must\n\
2780	be appropriate for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2781	@var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.\n\
2782	@var{bit_code} is @code{AND} or @code{IOR}, which is the op on the compares.",
2783	rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, rtx_code cmp_code, tree op0, tree op1, rtx_code bit_code),
2784	NULL)
2785
2786	/* Return a new value for loop unroll size. */
2787	DEFHOOK
2788	(loop_unroll_adjust,
2789	"This target hook returns a new value for the number of times @var{loop}\n\
2790	should be unrolled. The parameter @var{nunroll} is the number of times\n\
2791	the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2792	the loop, which is going to be checked for unrolling. This target hook\n\
2793	is required only when the target has special constraints like maximum\n\
2794	number of memory accesses.",
2795	unsigned, (unsigned nunroll, class loop *loop),
2796	NULL)
2797
2798	/* True if X is a legitimate MODE-mode immediate operand. */
2799	DEFHOOK
2800	(legitimate_constant_p,
2801	"This hook returns true if @var{x} is a legitimate constant for a\n\
2802	@var{mode}-mode immediate operand on the target machine. You can assume that\n\
2803	@var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2804	\n\
2805	The default definition returns true.",
2806	bool, (machine_mode mode, rtx x),
2807	hook_bool_mode_rtx_true)
2808
2809	/* True if X is a TLS operand whose value should be pre-computed. */
2810	DEFHOOK
2811	(precompute_tls_p,
2812	"This hook returns true if @var{x} is a TLS operand on the target\n\
2813	machine that should be pre-computed when used as the argument in a call.\n\
2814	You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not \n\
2815	check this.\n\
2816	\n\
2817	The default definition returns false.",
2818	bool, (machine_mode mode, rtx x),
2819	hook_bool_mode_rtx_false)
2820
2821	/* True if the constant X cannot be placed in the constant pool. */
2822	DEFHOOK
2823	(cannot_force_const_mem,
2824	"This hook should return true if @var{x} is of a form that cannot (or\n\
2825	should not) be spilled to the constant pool. @var{mode} is the mode\n\
2826	of @var{x}.\n\
2827	\n\
2828	The default version of this hook returns false.\n\
2829	\n\
2830	The primary reason to define this hook is to prevent reload from\n\
2831	deciding that a non-legitimate constant would be better reloaded\n\
2832	from the constant pool instead of spilling and reloading a register\n\
2833	holding the constant. This restriction is often true of addresses\n\
2834	of TLS symbols for various targets.",
2835	bool, (machine_mode mode, rtx x),
2836	hook_bool_mode_rtx_false)
2837
2838	DEFHOOK_UNDOC
2839	(cannot_copy_insn_p,
2840	"True if the insn @var{x} cannot be duplicated.",
2841	bool, (rtx_insn *), NULL)
2842
2843	/* True if X is considered to be commutative. */
2844	DEFHOOK
2845	(commutative_p,
2846	"This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2847	Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2848	PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2849	of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2850	bool, (const_rtx x, int outer_code),
2851	hook_bool_const_rtx_commutative_p)
2852
2853	/* True if ADDR is an address-expression whose effect depends
2854	on the mode of the memory reference it is used in. */
2855	DEFHOOK
2856	(mode_dependent_address_p,
2857	"This hook returns @code{true} if memory address @var{addr} in address\n\
2858	space @var{addrspace} can have\n\
2859	different meanings depending on the machine mode of the memory\n\
2860	reference it is used for or if the address is valid for some modes\n\
2861	but not others.\n\
2862	\n\
2863	Autoincrement and autodecrement addresses typically have mode-dependent\n\
2864	effects because the amount of the increment or decrement is the size\n\
2865	of the operand being addressed. Some machines have other mode-dependent\n\
2866	addresses. Many RISC machines have no mode-dependent addresses.\n\
2867	\n\
2868	You may assume that @var{addr} is a valid address for the machine.\n\
2869	\n\
2870	The default version of this hook returns @code{false}.",
2871	bool, (const_rtx addr, addr_space_t addrspace),
2872	default_mode_dependent_address_p)
2873
2874	/* Given an invalid address X for a given machine mode, try machine-specific
2875	ways to make it legitimate. Return X or an invalid address on failure. */
2876	DEFHOOK
2877	(legitimize_address,
2878	"This hook is given an invalid memory address @var{x} for an\n\
2879	operand of mode @var{mode} and should try to return a valid memory\n\
2880	address.\n\
2881	\n\
2882	@findex break_out_memory_refs\n\
2883	@var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2884	and @var{oldx} will be the operand that was given to that function to produce\n\
2885	@var{x}.\n\
2886	\n\
2887	The code of the hook should not alter the substructure of\n\
2888	@var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2889	should return the new @var{x}.\n\
2890	\n\
2891	It is not necessary for this hook to come up with a legitimate address,\n\
2892	with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2893	The compiler has standard ways of doing so in all cases. In fact, if\n\
2894	the target supports only emulated TLS, it\n\
2895	is safe to omit this hook or make it return @var{x} if it cannot find\n\
2896	a valid way to legitimize the address. But often a machine-dependent\n\
2897	strategy can generate better code.",
2898	rtx, (rtx x, rtx oldx, machine_mode mode),
2899	default_legitimize_address)
2900
2901	/* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2902	DEFHOOK
2903	(delegitimize_address,
2904	"This hook is used to undo the possibly obfuscating effects of the\n\
2905	@code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2906	macros. Some backend implementations of these macros wrap symbol\n\
2907	references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2908	addressing modes. This target hook allows GCC's optimizers to understand\n\
2909	the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2910	into their original form.",
2911	rtx, (rtx x),
2912	delegitimize_mem_from_attrs)
2913
2914	/* Given an RTX, return true if it is not ok to emit it into debug info
2915	section. */
2916	DEFHOOK
2917	(const_not_ok_for_debug_p,
2918	"This hook should return true if @var{x} should not be emitted into\n\
2919	debug sections.",
2920	bool, (rtx x),
2921	default_const_not_ok_for_debug_p)
2922
2923	/* Given an address RTX, say whether it is valid. */
2924	DEFHOOK
2925	(legitimate_address_p,
2926	"A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2927	address on the target machine for a memory operand of mode @var{mode}.\n\
2928	If @var{ch} is not @code{ERROR_MARK}, it can be called from middle-end to\n\
2929	determine if it is valid to use @var{x} as a memory operand for RTX insn\n\
2930	which is generated for the given code_helper @var{ch}. For example,\n\
2931	assuming the given @var{ch} is IFN_LEN_LOAD, on some target its underlying\n\
2932	hardware instructions support fewer addressing modes than what are for the\n\
2933	normal vector load and store, then with this @var{ch} target can know the\n\
2934	actual use context and return more exact result.\n\
2935	\n\
2936	Legitimate addresses are defined in two variants: a strict variant and a\n\
2937	non-strict one. The @var{strict} parameter chooses which variant is\n\
2938	desired by the caller.\n\
2939	\n\
2940	The strict variant is used in the reload pass. It must be defined so\n\
2941	that any pseudo-register that has not been allocated a hard register is\n\
2942	considered a memory reference. This is because in contexts where some\n\
2943	kind of register is required, a pseudo-register with no hard register\n\
2944	must be rejected. For non-hard registers, the strict variant should look\n\
2945	up the @code{reg_renumber} array; it should then proceed using the hard\n\
2946	register number in the array, or treat the pseudo as a memory reference\n\
2947	if the array holds @code{-1}.\n\
2948	\n\
2949	The non-strict variant is used in other passes. It must be defined to\n\
2950	accept all pseudo-registers in every context where some kind of\n\
2951	register is required.\n\
2952	\n\
2953	Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2954	and an integer are stored inside a @code{const} RTX to mark them as\n\
2955	constant. Therefore, there is no need to recognize such sums\n\
2956	specifically as legitimate addresses. Normally you would simply\n\
2957	recognize any @code{const} as legitimate.\n\
2958	\n\
2959	Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2960	sums that are not marked with @code{const}. It assumes that a naked\n\
2961	@code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2962	naked constant sums as illegitimate addresses, so that none of them will\n\
2963	be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2964	\n\
2965	@cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2966	On some machines, whether a symbolic address is legitimate depends on\n\
2967	the section that the address refers to. On these machines, define the\n\
2968	target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2969	into the @code{symbol_ref}, and then check for it here. When you see a\n\
2970	@code{const}, you will have to look inside it to find the\n\
2971	@code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2972	Format}.\n\
2973	\n\
2974	@cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2975	Some ports are still using a deprecated legacy substitute for\n\
2976	this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2977	has this syntax:\n\
2978	\n\
2979	@example\n\
2980	#define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2981	@end example\n\
2982	\n\
2983	@noindent\n\
2984	and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2985	address on the target machine for a memory operand of mode @var{mode}.\n\
2986	\n\
2987	@findex REG_OK_STRICT\n\
2988	Compiler source files that want to use the strict variant of this\n\
2989	macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2990	@code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2991	that case and the non-strict variant otherwise.\n\
2992	\n\
2993	Using the hook is usually simpler because it limits the number of\n\
2994	files that are recompiled when changes are made.",
2995	bool, (machine_mode mode, rtx x, bool strict, code_helper ch),
2996	default_legitimate_address_p)
2997
2998	/* True if the given constant can be put into an object_block. */
2999	DEFHOOK
3000	(use_blocks_for_constant_p,
3001	"This hook should return true if pool entries for constant @var{x} can\n\
3002	be placed in an @code{object_block} structure. @var{mode} is the mode\n\
3003	of @var{x}.\n\
3004	\n\
3005	The default version returns false for all constants.",
3006	bool, (machine_mode mode, const_rtx x),
3007	hook_bool_mode_const_rtx_false)
3008
3009	/* True if the given decl can be put into an object_block. */
3010	DEFHOOK
3011	(use_blocks_for_decl_p,
3012	"This hook should return true if pool entries for @var{decl} should\n\
3013	be placed in an @code{object_block} structure.\n\
3014	\n\
3015	The default version returns true for all decls.",
3016	bool, (const_tree decl),
3017	hook_bool_const_tree_true)
3018
3019	/* The minimum and maximum byte offsets for anchored addresses. */
3020	DEFHOOKPOD
3021	(min_anchor_offset,
3022	"The minimum offset that should be applied to a section anchor.\n\
3023	On most targets, it should be the smallest offset that can be\n\
3024	applied to a base register while still giving a legitimate address\n\
3025	for every mode. The default value is 0.",
3026	HOST_WIDE_INT, 0)
3027
3028	DEFHOOKPOD
3029	(max_anchor_offset,
3030	"Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
3031	offset that should be applied to section anchors. The default\n\
3032	value is 0.",
3033	HOST_WIDE_INT, 0)
3034
3035	/* True if section anchors can be used to access the given symbol. */
3036	DEFHOOK
3037	(use_anchors_for_symbol_p,
3038	"Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
3039	@var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
3040	@samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
3041	\n\
3042	The default version is correct for most targets, but you might need to\n\
3043	intercept this hook to handle things like target-specific attributes\n\
3044	or target-specific sections.",
3045	bool, (const_rtx x),
3046	default_use_anchors_for_symbol_p)
3047
3048	/* True if target supports indirect functions. */
3049	DEFHOOK
3050	(has_ifunc_p,
3051	"It returns true if the target supports GNU indirect functions.\n\
3052	The support includes the assembler, linker and dynamic linker.\n\
3053	The default value of this hook is based on target's libc.",
3054	bool, (void),
3055	default_has_ifunc_p)
3056
3057	/* True if it is OK to reference indirect function resolvers locally. */
3058	DEFHOOK
3059	(ifunc_ref_local_ok,
3060	"Return true if it is OK to reference indirect function resolvers\n\
3061	locally. The default is to return false.",
3062	bool, (void),
3063	hook_bool_void_false)
3064
3065	/* True if it is OK to do sibling call optimization for the specified
3066	call expression EXP. DECL will be the called function, or NULL if
3067	this is an indirect call. */
3068	DEFHOOK
3069	(function_ok_for_sibcall,
3070	"True if it is OK to do sibling call optimization for the specified\n\
3071	call expression @var{exp}. @var{decl} will be the called function,\n\
3072	or @code{NULL} if this is an indirect call.\n\
3073	\n\
3074	It is not uncommon for limitations of calling conventions to prevent\n\
3075	tail calls to functions outside the current unit of translation, or\n\
3076	during PIC compilation. The hook is used to enforce these restrictions,\n\
3077	as the @code{sibcall} md pattern cannot fail, or fall over to a\n\
3078	``normal'' call. The criteria for successful sibling call optimization\n\
3079	may vary greatly between different architectures.",
3080	bool, (tree decl, tree exp),
3081	hook_bool_tree_tree_false)
3082
3083	/* Establish appropriate back-end context for processing the function
3084	FNDECL. The argument might be NULL to indicate processing at top
3085	level, outside of any function scope. */
3086	DEFHOOK
3087	(set_current_function,
3088	"The compiler invokes this hook whenever it changes its current function\n\
3089	context (@code{cfun}). You can define this function if\n\
3090	the back end needs to perform any initialization or reset actions on a\n\
3091	per-function basis. For example, it may be used to implement function\n\
3092	attributes that affect register usage or code generation patterns.\n\
3093	The argument @var{decl} is the declaration for the new function context,\n\
3094	and may be null to indicate that the compiler has left a function context\n\
3095	and is returning to processing at the top level.\n\
3096	The default hook function does nothing.\n\
3097	\n\
3098	GCC sets @code{cfun} to a dummy function context during initialization of\n\
3099	some parts of the back end. The hook function is not invoked in this\n\
3100	situation; you need not worry about the hook being invoked recursively,\n\
3101	or when the back end is in a partially-initialized state.\n\
3102	@code{cfun} might be @code{NULL} to indicate processing at top level,\n\
3103	outside of any function scope.",
3104	void, (tree decl), hook_void_tree)
3105
3106	/* True if EXP should be placed in a "small data" section. */
3107	DEFHOOK
3108	(in_small_data_p,
3109	"Returns true if @var{exp} should be placed into a ``small data'' section.\n\
3110	The default version of this hook always returns false.",
3111	bool, (const_tree exp),
3112	hook_bool_const_tree_false)
3113
3114	/* True if EXP names an object for which name resolution must resolve
3115	to the current executable or shared library. */
3116	DEFHOOK
3117	(binds_local_p,
3118	"Returns true if @var{exp} names an object for which name resolution\n\
3119	rules must resolve to the current ``module'' (dynamic shared library\n\
3120	or executable image).\n\
3121	\n\
3122	The default version of this hook implements the name resolution rules\n\
3123	for ELF, which has a looser model of global name binding than other\n\
3124	currently supported object file formats.",
3125	bool, (const_tree exp),
3126	default_binds_local_p)
3127
3128	/* Check if profiling code is before or after prologue. */
3129	DEFHOOK
3130	(profile_before_prologue,
3131	"It returns true if target wants profile code emitted before prologue.\n\n\
3132	The default version of this hook use the target macro\n\
3133	@code{PROFILE_BEFORE_PROLOGUE}.",
3134	bool, (void),
3135	default_profile_before_prologue)
3136
3137	/* Return true if a leaf function should stay leaf even with profiling
3138	enabled. */
3139	DEFHOOK
3140	(keep_leaf_when_profiled,
3141	"This target hook returns true if the target wants the leaf flag for\n\
3142	the current function to stay true even if it calls mcount. This might\n\
3143	make sense for targets using the leaf flag only to determine whether a\n\
3144	stack frame needs to be generated or not and for which the call to\n\
3145	mcount is generated before the function prologue.",
3146	bool, (void),
3147	default_keep_leaf_when_profiled)
3148
3149	/* Modify and return the identifier of a DECL's external name,
3150	originally identified by ID, as required by the target,
3151	(eg, append @nn to windows32 stdcall function names).
3152	The default is to return ID without modification. */
3153	DEFHOOK
3154	(mangle_decl_assembler_name,
3155	"Define this hook if you need to postprocess the assembler name generated\n\
3156	by target-independent code. The @var{id} provided to this hook will be\n\
3157	the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
3158	or the mangled name of the @var{decl} in C++). The return value of the\n\
3159	hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
3160	your target system. The default implementation of this hook just\n\
3161	returns the @var{id} provided.",
3162	tree, (tree decl, tree id),
3163	default_mangle_decl_assembler_name)
3164
3165	/* Do something target-specific to record properties of the DECL into
3166	the associated SYMBOL_REF. */
3167	DEFHOOK
3168	(encode_section_info,
3169	"Define this hook if references to a symbol or a constant must be\n\
3170	treated differently depending on something about the variable or\n\
3171	function named by the symbol (such as what section it is in).\n\
3172	\n\
3173	The hook is executed immediately after rtl has been created for\n\
3174	@var{decl}, which may be a variable or function declaration or\n\
3175	an entry in the constant pool. In either case, @var{rtl} is the\n\
3176	rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3177	in this hook; that field may not have been initialized yet.\n\
3178	\n\
3179	In the case of a constant, it is safe to assume that the rtl is\n\
3180	a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3181	will also have this form, but that is not guaranteed. Global\n\
3182	register variables, for instance, will have a @code{reg} for their\n\
3183	rtl. (Normally the right thing to do with such unusual rtl is\n\
3184	leave it alone.)\n\
3185	\n\
3186	The @var{new_decl_p} argument will be true if this is the first time\n\
3187	that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3188	be false for subsequent invocations, which will happen for duplicate\n\
3189	declarations. Whether or not anything must be done for the duplicate\n\
3190	declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3191	@var{new_decl_p} is always true when the hook is called for a constant.\n\
3192	\n\
3193	@cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3194	The usual thing for this hook to do is to record flags in the\n\
3195	@code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3196	Historically, the name string was modified if it was necessary to\n\
3197	encode more than one bit of information, but this practice is now\n\
3198	discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3199	\n\
3200	The default definition of this hook, @code{default_encode_section_info}\n\
3201	in @file{varasm.cc}, sets a number of commonly-useful bits in\n\
3202	@code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3203	before overriding it.",
3204	void, (tree decl, rtx rtl, int new_decl_p),
3205	default_encode_section_info)
3206
3207	/* Undo the effects of encode_section_info on the symbol string. */
3208	DEFHOOK
3209	(strip_name_encoding,
3210	"Decode @var{name} and return the real name part, sans\n\
3211	the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3212	may have added.",
3213	const char *, (const char *name),
3214	default_strip_name_encoding)
3215
3216	/* If shift optabs for MODE are known to always truncate the shift count,
3217	return the mask that they apply. Return 0 otherwise. */
3218	DEFHOOK
3219	(shift_truncation_mask,
3220	"This function describes how the standard shift patterns for @var{mode}\n\
3221	deal with shifts by negative amounts or by more than the width of the mode.\n\
3222	@xref{shift patterns}.\n\
3223	\n\
3224	On many machines, the shift patterns will apply a mask @var{m} to the\n\
3225	shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3226	equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3227	this is true for mode @var{mode}, the function should return @var{m},\n\
3228	otherwise it should return 0. A return value of 0 indicates that no\n\
3229	particular behavior is guaranteed.\n\
3230	\n\
3231	Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3232	@emph{not} apply to general shift rtxes; it applies only to instructions\n\
3233	that are generated by the named shift patterns.\n\
3234	\n\
3235	The default implementation of this function returns\n\
3236	@code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3237	and 0 otherwise. This definition is always safe, but if\n\
3238	@code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3239	nevertheless truncate the shift count, you may get better code\n\
3240	by overriding it.",
3241	unsigned HOST_WIDE_INT, (machine_mode mode),
3242	default_shift_truncation_mask)
3243
3244	/* Return the number of divisions in the given MODE that should be present,
3245	so that it is profitable to turn the division into a multiplication by
3246	the reciprocal. */
3247	DEFHOOK
3248	(min_divisions_for_recip_mul,
3249	"When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3250	divisions by the same divisor, by turning them into multiplications by\n\
3251	the reciprocal. This target hook specifies the minimum number of divisions\n\
3252	that should be there for GCC to perform the optimization for a variable\n\
3253	of mode @var{mode}. The default implementation returns 3 if the machine\n\
3254	has an instruction for the division, and 2 if it does not.",
3255	unsigned int, (machine_mode mode),
3256	default_min_divisions_for_recip_mul)
3257
3258	DEFHOOK
3259	(truly_noop_truncation,
3260	"This hook returns true if it is safe to ``convert'' a value of\n\
3261	@var{inprec} bits to one of @var{outprec} bits (where @var{outprec} is\n\
3262	smaller than @var{inprec}) by merely operating on it as if it had only\n\
3263	@var{outprec} bits. The default returns true unconditionally, which\n\
3264	is correct for most machines. When @code{TARGET_TRULY_NOOP_TRUNCATION}\n\
3265	returns false, the machine description should provide a @code{trunc}\n\
3266	optab to specify the RTL that performs the required truncation.\n\
3267	\n\
3268	If @code{TARGET_MODES_TIEABLE_P} returns false for a pair of modes,\n\
3269	suboptimal code can result if this hook returns true for the corresponding\n\
3270	mode sizes. Making this hook return false in such cases may improve things.",
3271	bool, (poly_uint64 outprec, poly_uint64 inprec),
3272	hook_bool_puint64_puint64_true)
3273
3274	/* If the representation of integral MODE is such that values are
3275	always sign-extended to a wider mode MODE_REP then return
3276	SIGN_EXTEND. Return UNKNOWN otherwise. */
3277	/* Note that the return type ought to be RTX_CODE, but that's not
3278	necessarily defined at this point. */
3279	DEFHOOK
3280	(mode_rep_extended,
3281	"The representation of an integral mode can be such that the values\n\
3282	are always extended to a wider integral mode. Return\n\
3283	@code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3284	sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3285	otherwise. (Currently, none of the targets use zero-extended\n\
3286	representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3287	@code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3288	@code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3289	@var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3290	widest integral mode and currently we take advantage of this fact.)\n\
3291	\n\
3292	Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3293	value even if the extension is not performed on certain hard registers\n\
3294	as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3295	@code{TARGET_CAN_CHANGE_MODE_CLASS} returns false.\n\
3296	\n\
3297	Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3298	describe two related properties. If you define\n\
3299	@code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3300	to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3301	extension.\n\
3302	\n\
3303	In order to enforce the representation of @code{mode},\n\
3304	@code{TARGET_TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3305	@code{mode}.",
3306	int, (scalar_int_mode mode, scalar_int_mode rep_mode),
3307	default_mode_rep_extended)
3308
3309	DEFHOOK
3310	(setjmp_preserves_nonvolatile_regs_p,
3311	"On some targets, it is assumed that the compiler will spill all pseudos\n\
3312	that are live across a call to @code{setjmp}, while other targets treat\n\
3313	@code{setjmp} calls as normal function calls.\n\
3314	\n\
3315	This hook returns false if @code{setjmp} calls do not preserve all\n\
3316	non-volatile registers so that gcc that must spill all pseudos that are\n\
3317	live across @code{setjmp} calls. Define this to return true if the\n\
3318	target does not need to spill all pseudos live across @code{setjmp} calls.\n\
3319	The default implementation conservatively assumes all pseudos must be\n\
3320	spilled across @code{setjmp} calls.",
3321	bool, (void),
3322	hook_bool_void_false)
3323
3324	/* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3325	DEFHOOK
3326	(valid_pointer_mode,
3327	"Define this to return nonzero if the port can handle pointers\n\
3328	with machine mode @var{mode}. The default version of this\n\
3329	hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3330	bool, (scalar_int_mode mode),
3331	default_valid_pointer_mode)
3332
3333	/* Disambiguate with errno. */
3334	DEFHOOK
3335	(ref_may_alias_errno,
3336	"Define this to return nonzero if the memory reference @var{ref}\n\
3337	may alias with the system C library errno location. The default\n\
3338	version of this hook assumes the system C library errno location\n\
3339	is either a declaration of type int or accessed by dereferencing\n\
3340	a pointer to int.",
3341	bool, (ao_ref *ref),
3342	default_ref_may_alias_errno)
3343
3344	/* Support for named address spaces. */
3345	#undef HOOK_PREFIX
3346	#define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3347	HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3348
3349	/* MODE to use for a pointer into another address space. */
3350	DEFHOOK
3351	(pointer_mode,
3352	"Define this to return the machine mode to use for pointers to\n\
3353	@var{address_space} if the target supports named address spaces.\n\
3354	The default version of this hook returns @code{ptr_mode}.",
3355	scalar_int_mode, (addr_space_t address_space),
3356	default_addr_space_pointer_mode)
3357
3358	/* MODE to use for an address in another address space. */
3359	DEFHOOK
3360	(address_mode,
3361	"Define this to return the machine mode to use for addresses in\n\
3362	@var{address_space} if the target supports named address spaces.\n\
3363	The default version of this hook returns @code{Pmode}.",
3364	scalar_int_mode, (addr_space_t address_space),
3365	default_addr_space_address_mode)
3366
3367	/* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3368	in another address space. */
3369	DEFHOOK
3370	(valid_pointer_mode,
3371	"Define this to return nonzero if the port can handle pointers\n\
3372	with machine mode @var{mode} to address space @var{as}. This target\n\
3373	hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3374	except that it includes explicit named address space support. The default\n\
3375	version of this hook returns true for the modes returned by either the\n\
3376	@code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3377	target hooks for the given address space.",
3378	bool, (scalar_int_mode mode, addr_space_t as),
3379	default_addr_space_valid_pointer_mode)
3380
3381	/* True if an address is a valid memory address to a given named address
3382	space for a given mode. */
3383	DEFHOOK
3384	(legitimate_address_p,
3385	"Define this to return true if @var{exp} is a valid address for mode\n\
3386	@var{mode} in the named address space @var{as} with the use context\n\
3387	@var{ch}. The @var{strict} parameter says whether strict addressing\n\
3388	is in effect after reload has finished. The @var{ch} indicates what\n\
3389	context @var{exp} will be used for. This target hook is the same as the\n\
3390	@code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3391	explicit named address space support.",
3392	bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as, code_helper ch),
3393	default_addr_space_legitimate_address_p)
3394
3395	/* Return an updated address to convert an invalid pointer to a named
3396	address space to a valid one. If NULL_RTX is returned use machine
3397	independent methods to make the address valid. */
3398	DEFHOOK
3399	(legitimize_address,
3400	"Define this to modify an invalid address @var{x} to be a valid address\n\
3401	with mode @var{mode} in the named address space @var{as}. This target\n\
3402	hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3403	except that it includes explicit named address space support.",
3404	rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3405	default_addr_space_legitimize_address)
3406
3407	/* True if one named address space is a subset of another named address. */
3408	DEFHOOK
3409	(subset_p,
3410	"Define this to return whether the @var{subset} named address space is\n\
3411	contained within the @var{superset} named address space. Pointers to\n\
3412	a named address space that is a subset of another named address space\n\
3413	will be converted automatically without a cast if used together in\n\
3414	arithmetic operations. Pointers to a superset address space can be\n\
3415	converted to pointers to a subset address space via explicit casts.",
3416	bool, (addr_space_t subset, addr_space_t superset),
3417	default_addr_space_subset_p)
3418
3419	/* True if 0 is a valid address in the address space, or false if
3420	0 is a NULL in the address space. */
3421	DEFHOOK
3422	(zero_address_valid,
3423	"Define this to modify the default handling of address 0 for the\n\
3424	address space. Return true if 0 should be considered a valid address.",
3425	bool, (addr_space_t as),
3426	default_addr_space_zero_address_valid)
3427
3428	/* Function to convert an rtl expression from one address space to another. */
3429	DEFHOOK
3430	(convert,
3431	"Define this to convert the pointer expression represented by the RTL\n\
3432	@var{op} with type @var{from_type} that points to a named address\n\
3433	space to a new pointer expression with type @var{to_type} that points\n\
3434	to a different named address space. When this hook it called, it is\n\
3435	guaranteed that one of the two address spaces is a subset of the other,\n\
3436	as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3437	rtx, (rtx op, tree from_type, tree to_type),
3438	default_addr_space_convert)
3439
3440	/* Function to encode an address space into dwarf. */
3441	DEFHOOK
3442	(debug,
3443	"Define this to define how the address space is encoded in dwarf.\n\
3444	The result is the value to be used with @code{DW_AT_address_class}.",
3445	int, (addr_space_t as),
3446	default_addr_space_debug)
3447
3448	/* Function to emit custom diagnostic if an address space is used. */
3449	DEFHOOK
3450	(diagnose_usage,
3451	"Define this hook if the availability of an address space depends on\n\
3452	command line options and some diagnostics should be printed when the\n\
3453	address space is used. This hook is called during parsing and allows\n\
3454	to emit a better diagnostic compared to the case where the address space\n\
3455	was not registered with @code{c_register_addr_space}. @var{as} is\n\
3456	the address space as registered with @code{c_register_addr_space}.\n\
3457	@var{loc} is the location of the address space qualifier token.\n\
3458	The default implementation does nothing.",
3459	void, (addr_space_t as, location_t loc),
3460	default_addr_space_diagnose_usage)
3461
3462	HOOK_VECTOR_END (addr_space)
3463
3464	#undef HOOK_PREFIX
3465	#define HOOK_PREFIX "TARGET_"
3466
3467	DEFHOOK
3468	(lower_local_decl_alignment,
3469	"Define this hook to lower alignment of local, parm or result\n\
3470	decl @samp{(@var{decl})}.",
3471	void, (tree decl),
3472	hook_void_tree)
3473
3474	DEFHOOK
3475	(static_rtx_alignment,
3476	"This hook returns the preferred alignment in bits for a\n\
3477	statically-allocated rtx, such as a constant pool entry. @var{mode}\n\
3478	is the mode of the rtx. The default implementation returns\n\
3479	@samp{GET_MODE_ALIGNMENT (@var{mode})}.",
3480	HOST_WIDE_INT, (machine_mode mode),
3481	default_static_rtx_alignment)
3482
3483	DEFHOOK
3484	(constant_alignment,
3485	"This hook returns the alignment in bits of a constant that is being\n\
3486	placed in memory. @var{constant} is the constant and @var{basic_align}\n\
3487	is the alignment that the object would ordinarily have.\n\
3488	\n\
3489	The default definition just returns @var{basic_align}.\n\
3490	\n\
3491	The typical use of this hook is to increase alignment for string\n\
3492	constants to be word aligned so that @code{strcpy} calls that copy\n\
3493	constants can be done inline. The function\n\
3494	@code{constant_alignment_word_strings} provides such a definition.",
3495	HOST_WIDE_INT, (const_tree constant, HOST_WIDE_INT basic_align),
3496	default_constant_alignment)
3497
3498	DEFHOOK
3499	(translate_mode_attribute,
3500	"Define this hook if during mode attribute processing, the port should\n\
3501	translate machine_mode @var{mode} to another mode. For example, rs6000's\n\
3502	@code{KFmode}, when it is the same as @code{TFmode}.\n\
3503	\n\
3504	The default version of the hook returns that mode that was passed in.",
3505	machine_mode, (machine_mode mode),
3506	default_translate_mode_attribute)
3507
3508	/* True if MODE is valid for the target. By "valid", we mean able to
3509	be manipulated in non-trivial ways. In particular, this means all
3510	the arithmetic is supported. */
3511	DEFHOOK
3512	(scalar_mode_supported_p,
3513	"Define this to return nonzero if the port is prepared to handle\n\
3514	insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3515	considered supported, all the basic arithmetic and comparisons\n\
3516	must work.\n\
3517	\n\
3518	The default version of this hook returns true for any mode\n\
3519	required to handle the basic C types (as defined by the port).\n\
3520	Included here are the double-word arithmetic supported by the\n\
3521	code in @file{optabs.cc}.",
3522	bool, (scalar_mode mode),
3523	default_scalar_mode_supported_p)
3524
3525	/* Similarly for vector modes. "Supported" here is less strict. At
3526	least some operations are supported; need to check optabs or builtins
3527	for further details. */
3528	DEFHOOK
3529	(vector_mode_supported_p,
3530	"Define this to return nonzero if the current target is prepared to handle\n\
3531	insns involving vector mode @var{mode}. At the very least, it\n\
3532	must have move patterns for this mode.",
3533	bool, (machine_mode mode),
3534	hook_bool_mode_false)
3535
3536	DEFHOOK
3537	(vector_mode_supported_any_target_p,
3538	"Define this to return nonzero if the port is prepared to handle\n\
3539	insns involving vector mode @var{mode} in any target configuration.\n\
3540	Returning @var{true} means that the mode can be used as the @samp{TYPE_MODE}\n\
3541	for vector types.\n\
3542	\n\
3543	The default version of this hook returns true. The final mode assigned to\n\
3544	@samp{TYPE_MODE} will also be checked against\n\
3545	@code{TARGET_VECTOR_MODE_SUPPORTED_P} to take target configuration into\n\
3546	account.",
3547	bool, (machine_mode mode),
3548	hook_bool_mode_true)
3549
3550	DEFHOOK
3551	(compatible_vector_types_p,
3552	"Return true if there is no target-specific reason for treating\n\
3553	vector types @var{type1} and @var{type2} as distinct types. The caller\n\
3554	has already checked for target-independent reasons, meaning that the\n\
3555	types are known to have the same mode, to have the same number of elements,\n\
3556	and to have what the caller considers to be compatible element types.\n\
3557	\n\
3558	The main reason for defining this hook is to reject pairs of types\n\
3559	that are handled differently by the target's calling convention.\n\
3560	For example, when a new @var{N}-bit vector architecture is added\n\
3561	to a target, the target may want to handle normal @var{N}-bit\n\
3562	@code{VECTOR_TYPE} arguments and return values in the same way as\n\
3563	before, to maintain backwards compatibility. However, it may also\n\
3564	provide new, architecture-specific @code{VECTOR_TYPE}s that are passed\n\
3565	and returned in a more efficient way. It is then important to maintain\n\
3566	a distinction between the ``normal'' @code{VECTOR_TYPE}s and the new\n\
3567	architecture-specific ones.\n\
3568	\n\
3569	The default implementation returns true, which is correct for most targets.",
3570	bool, (const_tree type1, const_tree type2),
3571	hook_bool_const_tree_const_tree_true)
3572
3573	DEFHOOK
3574	(vector_alignment,
3575	"This hook can be used to define the alignment for a vector of type\n\
3576	@var{type}, in order to comply with a platform ABI. The default is to\n\
3577	require natural alignment for vector types. The alignment returned by\n\
3578	this hook must be a power-of-two multiple of the default alignment of\n\
3579	the vector element type.",
3580	HOST_WIDE_INT, (const_tree type),
3581	default_vector_alignment)
3582
3583	DEFHOOK
3584	(array_mode,
3585	"Return the mode that GCC should use for an array that has\n\
3586	@var{nelems} elements, with each element having mode @var{mode}.\n\
3587	Return no mode if the target has no special requirements. In the\n\
3588	latter case, GCC looks for an integer mode of the appropriate size\n\
3589	if available and uses BLKmode otherwise. Usually the search for the\n\
3590	integer mode is limited to @code{MAX_FIXED_MODE_SIZE}, but the\n\
3591	@code{TARGET_ARRAY_MODE_SUPPORTED_P} hook allows a larger mode to be\n\
3592	used in specific cases.\n\
3593	\n\
3594	The main use of this hook is to specify that an array of vectors should\n\
3595	also have a vector mode. The default implementation returns no mode.",
3596	opt_machine_mode, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3597	hook_optmode_mode_uhwi_none)
3598
3599	/* True if we should try to use a scalar mode to represent an array,
3600	overriding the usual MAX_FIXED_MODE limit. */
3601	DEFHOOK
3602	(array_mode_supported_p,
3603	"Return true if GCC should try to use a scalar mode to store an array\n\
3604	of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3605	Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3606	and allows GCC to use any defined integer mode.\n\
3607	\n\
3608	One use of this hook is to support vector load and store operations\n\
3609	that operate on several homogeneous vectors. For example, ARM NEON\n\
3610	has operations like:\n\
3611	\n\
3612	@smallexample\n\
3613	int8x8x3_t vld3_s8 (const int8_t *)\n\
3614	@end smallexample\n\
3615	\n\
3616	where the return type is defined as:\n\
3617	\n\
3618	@smallexample\n\
3619	typedef struct int8x8x3_t\n\
3620	@{\n\
3621	int8x8_t val[3];\n\
3622	@} int8x8x3_t;\n\
3623	@end smallexample\n\
3624	\n\
3625	If this hook allows @code{val} to have a scalar mode, then\n\
3626	@code{int8x8x3_t} can have the same mode. GCC can then store\n\
3627	@code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3628	bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3629	hook_bool_mode_uhwi_false)
3630
3631	DEFHOOK
3632	(libgcc_floating_mode_supported_p,
3633	"Define this to return nonzero if libgcc provides support for the \n\
3634	floating-point mode @var{mode}, which is known to pass \n\
3635	@code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3636	hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3637	@code{XFmode} and @code{TFmode}, if such modes exist.",
3638	bool, (scalar_float_mode mode),
3639	default_libgcc_floating_mode_supported_p)
3640
3641	DEFHOOK
3642	(floatn_mode,
3643	"Define this to return the machine mode to use for the type \n\
3644	@code{_Float@var{n}}, if @var{extended} is false, or the type \n\
3645	@code{_Float@var{n}x}, if @var{extended} is true. If such a type is not\n\
3646	supported, return @code{opt_scalar_float_mode ()}. The default version of\n\
3647	this hook returns @code{SFmode} for @code{_Float32}, @code{DFmode} for\n\
3648	@code{_Float64} and @code{_Float32x} and @code{TFmode} for \n\
3649	@code{_Float128}, if those modes exist and satisfy the requirements for \n\
3650	those types and pass @code{TARGET_SCALAR_MODE_SUPPORTED_P} and \n\
3651	@code{TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P}; for @code{_Float64x}, it \n\
3652	returns the first of @code{XFmode} and @code{TFmode} that exists and \n\
3653	satisfies the same requirements; for other types, it returns \n\
3654	@code{opt_scalar_float_mode ()}. The hook is only called for values\n\
3655	of @var{n} and @var{extended} that are valid according to\n\
3656	ISO/IEC TS 18661-3:2015; that is, @var{n} is one of 32, 64, 128, or,\n\
3657	if @var{extended} is false, 16 or greater than 128 and a multiple of 32.",
3658	opt_scalar_float_mode, (int n, bool extended),
3659	default_floatn_mode)
3660
3661	DEFHOOK
3662	(floatn_builtin_p,
3663	"Define this to return true if the @code{_Float@var{n}} and\n\
3664	@code{_Float@var{n}x} built-in functions should implicitly enable the\n\
3665	built-in function without the @code{__builtin_} prefix in addition to the\n\
3666	normal built-in function with the @code{__builtin_} prefix. The default is\n\
3667	to only enable built-in functions without the @code{__builtin_} prefix for\n\
3668	the GNU C langauge. In strict ANSI/ISO mode, the built-in function without\n\
3669	the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is the\n\
3670	@code{enum built_in_function} id of the function to be enabled.",
3671	bool, (int func),
3672	default_floatn_builtin_p)
3673
3674	/* Compute cost of moving data from a register of class FROM to one of
3675	TO, using MODE. */
3676	DEFHOOK
3677	(register_move_cost,
3678	"This target hook should return the cost of moving data of mode @var{mode}\n\
3679	from a register in class @var{from} to one in class @var{to}. The classes\n\
3680	are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3681	A value of 2 is the default; other values are interpreted relative to\n\
3682	that.\n\
3683	\n\
3684	It is not required that the cost always equal 2 when @var{from} is the\n\
3685	same as @var{to}; on some machines it is expensive to move between\n\
3686	registers if they are not general registers.\n\
3687	\n\
3688	If reload sees an insn consisting of a single @code{set} between two\n\
3689	hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3690	classes returns a value of 2, reload does not check to ensure that the\n\
3691	constraints of the insn are met. Setting a cost of other than 2 will\n\
3692	allow reload to verify that the constraints are met. You should do this\n\
3693	if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3694	\n\
3695	The default version of this function returns 2.",
3696	int, (machine_mode mode, reg_class_t from, reg_class_t to),
3697	default_register_move_cost)
3698
3699	/* Compute cost of moving registers to/from memory. */
3700	/* ??? Documenting the argument types for this hook requires a GFDL
3701	license grant. Also, the documentation uses a different name for RCLASS. */
3702	DEFHOOK
3703	(memory_move_cost,
3704	"This target hook should return the cost of moving data of mode @var{mode}\n\
3705	between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3706	if the value is to be written to memory, @code{true} if it is to be read in.\n\
3707	This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3708	If moving between registers and memory is more expensive than between two\n\
3709	registers, you should add this target hook to express the relative cost.\n\
3710	\n\
3711	If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3712	the cost of copying via a secondary reload register, if one is\n\
3713	needed. If your machine requires a secondary reload register to copy\n\
3714	between memory and a register of @var{rclass} but the reload mechanism is\n\
3715	more complex than copying via an intermediate, use this target hook to\n\
3716	reflect the actual cost of the move.\n\
3717	\n\
3718	GCC defines the function @code{memory_move_secondary_cost} if\n\
3719	secondary reloads are needed. It computes the costs due to copying via\n\
3720	a secondary register. If your machine copies from memory using a\n\
3721	secondary register in the conventional way but the default base value of\n\
3722	4 is not correct for your machine, use this target hook to add some other\n\
3723	value to the result of that function. The arguments to that function\n\
3724	are the same as to this target hook.",
3725	int, (machine_mode mode, reg_class_t rclass, bool in),
3726	default_memory_move_cost)
3727
3728	DEFHOOK
3729	(use_by_pieces_infrastructure_p,
3730	"GCC will attempt several strategies when asked to copy between\n\
3731	two areas of memory, or to set, clear or store to memory, for example\n\
3732	when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3733	implements such memory operations as a sequence of load, store or move\n\
3734	insns. Alternate strategies are to expand the\n\
3735	@code{cpymem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3736	unit-by-unit, loop-based operations.\n\
3737	\n\
3738	This target hook should return true if, for a memory operation with a\n\
3739	given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3740	infrastructure is expected to result in better code generation.\n\
3741	Both @var{size} and @var{alignment} are measured in terms of storage\n\
3742	units.\n\
3743	\n\
3744	The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3745	@code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\
3746	@code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\
3747	under consideration.\n\
3748	\n\
3749	The parameter @var{speed_p} is true if the code is currently being\n\
3750	optimized for speed rather than size.\n\
3751	\n\
3752	Returning true for higher values of @var{size} can improve code generation\n\
3753	for speed if the target does not provide an implementation of the\n\
3754	@code{cpymem} or @code{setmem} standard names, if the @code{cpymem} or\n\
3755	@code{setmem} implementation would be more expensive than a sequence of\n\
3756	insns, or if the overhead of a library call would dominate that of\n\
3757	the body of the memory operation.\n\
3758	\n\
3759	Returning true for higher values of @code{size} may also cause an increase\n\
3760	in code size, for example where the number of insns emitted to perform a\n\
3761	move would be greater than that of a library call.",
3762	bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3763	enum by_pieces_operation op, bool speed_p),
3764	default_use_by_pieces_infrastructure_p)
3765
3766	DEFHOOK
3767	(overlap_op_by_pieces_p,
3768	"This target hook should return true if when the @code{by_pieces}\n\
3769	infrastructure is used, an offset adjusted unaligned memory operation\n\
3770	in the smallest integer mode for the last piece operation of a memory\n\
3771	region can be generated to avoid doing more than one smaller operations.",
3772	bool, (void),
3773	hook_bool_void_false)
3774
3775	DEFHOOK
3776	(compare_by_pieces_branch_ratio,
3777	"When expanding a block comparison in MODE, gcc can try to reduce the\n\
3778	number of branches at the expense of more memory operations. This hook\n\
3779	allows the target to override the default choice. It should return the\n\
3780	factor by which branches should be reduced over the plain expansion with\n\
3781	one comparison per @var{mode}-sized piece. A port can also prevent a\n\
3782	particular mode from being used for block comparisons by returning a\n\
3783	negative number from this hook.",
3784	int, (machine_mode mode),
3785	default_compare_by_pieces_branch_ratio)
3786
3787	DEFHOOK
3788	(slow_unaligned_access,
3789	"This hook returns true if memory accesses described by the\n\
3790	@var{mode} and @var{alignment} parameters have a cost many times greater\n\
3791	than aligned accesses, for example if they are emulated in a trap handler.\n\
3792	This hook is invoked only for unaligned accesses, i.e.@: when\n\
3793	@code{@var{alignment} < GET_MODE_ALIGNMENT (@var{mode})}.\n\
3794	\n\
3795	When this hook returns true, the compiler will act as if\n\
3796	@code{STRICT_ALIGNMENT} were true when generating code for block\n\
3797	moves. This can cause significantly more instructions to be produced.\n\
3798	Therefore, do not make this hook return true if unaligned accesses only\n\
3799	add a cycle or two to the time for a memory access.\n\
3800	\n\
3801	The hook must return true whenever @code{STRICT_ALIGNMENT} is true.\n\
3802	The default implementation returns @code{STRICT_ALIGNMENT}.",
3803	bool, (machine_mode mode, unsigned int align),
3804	default_slow_unaligned_access)
3805
3806	DEFHOOK
3807	(optab_supported_p,
3808	"Return true if the optimizers should use optab @var{op} with\n\
3809	modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\
3810	The optab is known to have an associated @file{.md} instruction\n\
3811	whose C condition is true. @var{mode2} is only meaningful for conversion\n\
3812	optabs; for direct optabs it is a copy of @var{mode1}.\n\
3813	\n\
3814	For example, when called with @var{op} equal to @code{rint_optab} and\n\
3815	@var{mode1} equal to @code{DFmode}, the hook should say whether the\n\
3816	optimizers should use optab @code{rintdf2}.\n\
3817	\n\
3818	The default hook returns true for all inputs.",
3819	bool, (int op, machine_mode mode1, machine_mode mode2,
3820	optimization_type opt_type),
3821	default_optab_supported_p)
3822
3823	/* True for MODE if the target expects that registers in this mode will
3824	be allocated to registers in a small register class. The compiler is
3825	allowed to use registers explicitly used in the rtl as spill registers
3826	but it should prevent extending the lifetime of these registers. */
3827	DEFHOOK
3828	(small_register_classes_for_mode_p,
3829	"Define this to return nonzero for machine modes for which the port has\n\
3830	small register classes. If this target hook returns nonzero for a given\n\
3831	@var{mode}, the compiler will try to minimize the lifetime of registers\n\
3832	in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3833	In this case, the hook is expected to return nonzero if it returns nonzero\n\
3834	for any mode.\n\
3835	\n\
3836	On some machines, it is risky to let hard registers live across arbitrary\n\
3837	insns. Typically, these machines have instructions that require values\n\
3838	to be in specific registers (like an accumulator), and reload will fail\n\
3839	if the required hard register is used for another purpose across such an\n\
3840	insn.\n\
3841	\n\
3842	Passes before reload do not know which hard registers will be used\n\
3843	in an instruction, but the machine modes of the registers set or used in\n\
3844	the instruction are already known. And for some machines, register\n\
3845	classes are small for, say, integer registers but not for floating point\n\
3846	registers. For example, the AMD x86-64 architecture requires specific\n\
3847	registers for the legacy x86 integer instructions, but there are many\n\
3848	SSE registers for floating point operations. On such targets, a good\n\
3849	strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3850	machine modes but zero for the SSE register classes.\n\
3851	\n\
3852	The default version of this hook returns false for any mode. It is always\n\
3853	safe to redefine this hook to return with a nonzero value. But if you\n\
3854	unnecessarily define it, you will reduce the amount of optimizations\n\
3855	that can be performed in some cases. If you do not define this hook\n\
3856	to return a nonzero value when it is required, the compiler will run out\n\
3857	of spill registers and print a fatal error message.",
3858	bool, (machine_mode mode),
3859	hook_bool_mode_false)
3860
3861	/* Register number for a flags register. Only needs to be defined if the
3862	target is constrainted to use post-reload comparison elimination. */
3863	DEFHOOKPOD
3864	(flags_regnum,
3865	"If the target has a dedicated flags register, and it needs to use the\n\
3866	post-reload comparison elimination pass, or the delay slot filler pass,\n\
3867	then this value should be set appropriately.",
3868	unsigned int, INVALID_REGNUM)
3869
3870	/* Compute a (partial) cost for rtx X. Return true if the complete
3871	cost has been computed, and false if subexpressions should be
3872	scanned. In either case, *TOTAL contains the cost result. */
3873	/* Note that OUTER_CODE ought to be RTX_CODE, but that's
3874	not necessarily defined at this point. */
3875	DEFHOOK
3876	(rtx_costs,
3877	"This target hook describes the relative costs of RTL expressions.\n\
3878	\n\
3879	The cost may depend on the precise form of the expression, which is\n\
3880	available for examination in @var{x}, and the fact that @var{x} appears\n\
3881	as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3882	That is, the hook can assume that there is some rtx @var{y} such\n\
3883	that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3884	either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3885	(b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3886	\n\
3887	@var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3888	do not have a mode, the mode in which @var{x} is used.\n\
3889	\n\
3890	In implementing this hook, you can use the construct\n\
3891	@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3892	instructions.\n\
3893	\n\
3894	On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3895	for the cost of the expression. The hook should modify this value as\n\
3896	necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3897	for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3898	operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3899	\n\
3900	When optimizing for code size, i.e.@: when @code{speed} is\n\
3901	false, this target hook should be used to estimate the relative\n\
3902	size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3903	\n\
3904	The hook returns true when all subexpressions of @var{x} have been\n\
3905	processed, and false when @code{rtx_cost} should recurse.",
3906	bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3907	hook_bool_rtx_mode_int_int_intp_bool_false)
3908
3909	/* Compute the cost of X, used as an address. Never called with
3910	invalid addresses. */
3911	DEFHOOK
3912	(address_cost,
3913	"This hook computes the cost of an addressing mode that contains\n\
3914	@var{address}. If not defined, the cost is computed from\n\
3915	the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3916	\n\
3917	For most CISC machines, the default cost is a good approximation of the\n\
3918	true cost of the addressing mode. However, on RISC machines, all\n\
3919	instructions normally have the same length and execution time. Hence\n\
3920	all addresses will have equal costs.\n\
3921	\n\
3922	In cases where more than one form of an address is known, the form with\n\
3923	the lowest cost will be used. If multiple forms have the same, lowest,\n\
3924	cost, the one that is the most complex will be used.\n\
3925	\n\
3926	For example, suppose an address that is equal to the sum of a register\n\
3927	and a constant is used twice in the same basic block. When this macro\n\
3928	is not defined, the address will be computed in a register and memory\n\
3929	references will be indirect through that register. On machines where\n\
3930	the cost of the addressing mode containing the sum is no higher than\n\
3931	that of a simple indirect reference, this will produce an additional\n\
3932	instruction and possibly require an additional register. Proper\n\
3933	specification of this macro eliminates this overhead for such machines.\n\
3934	\n\
3935	This hook is never called with an invalid address.\n\
3936	\n\
3937	On machines where an address involving more than one register is as\n\
3938	cheap as an address computation involving only one register, defining\n\
3939	@code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3940	be live over a region of code where only one would have been if\n\
3941	@code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3942	should be considered in the definition of this macro. Equivalent costs\n\
3943	should probably only be given to addresses with different numbers of\n\
3944	registers on machines with lots of registers.",
3945	int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3946	default_address_cost)
3947
3948	/* Compute a cost for INSN. */
3949	DEFHOOK
3950	(insn_cost,
3951	"This target hook describes the relative costs of RTL instructions.\n\
3952	\n\
3953	In implementing this hook, you can use the construct\n\
3954	@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3955	instructions.\n\
3956	\n\
3957	When optimizing for code size, i.e.@: when @code{speed} is\n\
3958	false, this target hook should be used to estimate the relative\n\
3959	size cost of an expression, again relative to @code{COSTS_N_INSNS}.",
3960	int, (rtx_insn *insn, bool speed), NULL)
3961
3962	/* Give a cost, in RTX Costs units, for an edge. Like BRANCH_COST, but with
3963	well defined units. */
3964	DEFHOOK
3965	(max_noce_ifcvt_seq_cost,
3966	"This hook returns a value in the same units as @code{TARGET_RTX_COSTS},\n\
3967	giving the maximum acceptable cost for a sequence generated by the RTL\n\
3968	if-conversion pass when conditional execution is not available.\n\
3969	The RTL if-conversion pass attempts to convert conditional operations\n\
3970	that would require a branch to a series of unconditional operations and\n\
3971	@code{mov@var{mode}cc} insns. This hook returns the maximum cost of the\n\
3972	unconditional instructions and the @code{mov@var{mode}cc} insns.\n\
3973	RTL if-conversion is cancelled if the cost of the converted sequence\n\
3974	is greater than the value returned by this hook.\n\
3975	\n\
3976	@code{e} is the edge between the basic block containing the conditional\n\
3977	branch to the basic block which would be executed if the condition\n\
3978	were true.\n\
3979	\n\
3980	The default implementation of this hook uses the\n\
3981	@code{max-rtl-if-conversion-[un]predictable} parameters if they are set,\n\
3982	and uses a multiple of @code{BRANCH_COST} otherwise.",
3983	unsigned int, (edge e),
3984	default_max_noce_ifcvt_seq_cost)
3985
3986	/* Return true if the given instruction sequence is a good candidate
3987	as a replacement for the if-convertible sequence. */
3988	DEFHOOK
3989	(noce_conversion_profitable_p,
3990	"This hook returns true if the instruction sequence @code{seq} is a good\n\
3991	candidate as a replacement for the if-convertible sequence described in\n\
3992	@code{if_info}.",
3993	bool, (rtx_insn *seq, struct noce_if_info *if_info),
3994	default_noce_conversion_profitable_p)
3995
3996	/* Return true if new_addr should be preferred over the existing address used by
3997	memref in insn. */
3998	DEFHOOK
3999	(new_address_profitable_p,
4000	"Return @code{true} if it is profitable to replace the address in\n\
4001	@var{memref} with @var{new_addr}. This allows targets to prevent the\n\
4002	scheduler from undoing address optimizations. The instruction containing the\n\
4003	memref is @var{insn}. The default implementation returns @code{true}.",
4004	bool, (rtx memref, rtx_insn * insn, rtx new_addr),
4005	default_new_address_profitable_p)
4006
4007	DEFHOOK
4008	(estimated_poly_value,
4009	"Return an estimate of the runtime value of @var{val}, for use in\n\
4010	things like cost calculations or profiling frequencies. @var{kind} is used\n\
4011	to ask for the minimum, maximum, and likely estimates of the value through\n\
4012	the @code{POLY_VALUE_MIN}, @code{POLY_VALUE_MAX} and\n\
4013	@code{POLY_VALUE_LIKELY} values. The default\n\
4014	implementation returns the lowest possible value of @var{val}.",
4015	HOST_WIDE_INT, (poly_int64 val, poly_value_estimate_kind kind),
4016	default_estimated_poly_value)
4017
4018	/* Permit speculative instructions in delay slots during delayed-branch
4019	scheduling. */
4020	DEFHOOK
4021	(no_speculation_in_delay_slots_p,
4022	"This predicate controls the use of the eager delay slot filler to disallow\n\
4023	speculatively executed instructions being placed in delay slots. Targets\n\
4024	such as certain MIPS architectures possess both branches with and without\n\
4025	delay slots. As the eager delay slot filler can decrease performance,\n\
4026	disabling it is beneficial when ordinary branches are available. Use of\n\
4027	delay slot branches filled using the basic filler is often still desirable\n\
4028	as the delay slot can hide a pipeline bubble.",
4029	bool, (void),
4030	hook_bool_void_false)
4031
4032	/* Return where to allocate pseudo for a given hard register initial value. */
4033	DEFHOOK
4034	(allocate_initial_value,
4035	"\n\
4036	When the initial value of a hard register has been copied in a pseudo\n\
4037	register, it is often not necessary to actually allocate another register\n\
4038	to this pseudo register, because the original hard register or a stack slot\n\
4039	it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
4040	is called at the start of register allocation once for each hard register\n\
4041	that had its initial value copied by using\n\
4042	@code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
4043	Possible values are @code{NULL_RTX}, if you don't want\n\
4044	to do any special allocation, a @code{REG} rtx---that would typically be\n\
4045	the hard register itself, if it is known not to be clobbered---or a\n\
4046	@code{MEM}.\n\
4047	If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
4048	it might decide to use another register anyways.\n\
4049	You may use @code{current_function_is_leaf} or \n\
4050	@code{REG_N_SETS} in the hook to determine if the hard\n\
4051	register in question will not be clobbered.\n\
4052	The default value of this hook is @code{NULL}, which disables any special\n\
4053	allocation.",
4054	rtx, (rtx hard_reg), NULL)
4055
4056	/* Return nonzero if evaluating UNSPEC X might cause a trap.
4057	FLAGS has the same meaning as in rtlanal.cc: may_trap_p_1. */
4058	DEFHOOK
4059	(unspec_may_trap_p,
4060	"This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
4061	@code{unspec_volatile} operation, might cause a trap. Targets can use\n\
4062	this hook to enhance precision of analysis for @code{unspec} and\n\
4063	@code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
4064	to analyze inner elements of @var{x} in which case @var{flags} should be\n\
4065	passed along.",
4066	int, (const_rtx x, unsigned flags),
4067	default_unspec_may_trap_p)
4068
4069	/* Given a register, this hook should return a parallel of registers
4070	to represent where to find the register pieces. Define this hook
4071	if the register and its mode are represented in Dwarf in
4072	non-contiguous locations, or if the register should be
4073	represented in more than one register in Dwarf. Otherwise, this
4074	hook should return NULL_RTX. */
4075	DEFHOOK
4076	(dwarf_register_span,
4077	"Given a register, this hook should return a parallel of registers to\n\
4078	represent where to find the register pieces. Define this hook if the\n\
4079	register and its mode are represented in Dwarf in non-contiguous\n\
4080	locations, or if the register should be represented in more than one\n\
4081	register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
4082	If not defined, the default is to return @code{NULL_RTX}.",
4083	rtx, (rtx reg),
4084	hook_rtx_rtx_null)
4085
4086	/* Given a register return the mode of the corresponding DWARF frame
4087	register. */
4088	DEFHOOK
4089	(dwarf_frame_reg_mode,
4090	"Given a register, this hook should return the mode which the\n\
4091	corresponding Dwarf frame register should have. This is normally\n\
4092	used to return a smaller mode than the raw mode to prevent call\n\
4093	clobbered parts of a register altering the frame register size",
4094	machine_mode, (int regno),
4095	default_dwarf_frame_reg_mode)
4096
4097	/* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
4098	entries not corresponding directly to registers below
4099	FIRST_PSEUDO_REGISTER, this hook should generate the necessary
4100	code, given the address of the table. */
4101	DEFHOOK
4102	(init_dwarf_reg_sizes_extra,
4103	"If some registers are represented in Dwarf-2 unwind information in\n\
4104	multiple pieces, define this hook to fill in information about the\n\
4105	sizes of those pieces in the table used by the unwinder at runtime.\n\
4106	It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
4107	filling in a single size corresponding to each hard register;\n\
4108	@var{address} is the address of the table.",
4109	void, (tree address),
4110	hook_void_tree)
4111
4112	/* Fetch the fixed register(s) which hold condition codes, for
4113	targets where it makes sense to look for duplicate assignments to
4114	the condition codes. This should return true if there is such a
4115	register, false otherwise. The arguments should be set to the
4116	fixed register numbers. Up to two condition code registers are
4117	supported. If there is only one for this target, the int pointed
4118	at by the second argument should be set to -1. */
4119	DEFHOOK
4120	(fixed_condition_code_regs,
4121	"On targets which use a hard\n\
4122	register rather than a pseudo-register to hold condition codes, the\n\
4123	regular CSE passes are often not able to identify cases in which the\n\
4124	hard register is set to a common value. Use this hook to enable a\n\
4125	small pass which optimizes such cases. This hook should return true\n\
4126	to enable this pass, and it should set the integers to which its\n\
4127	arguments point to the hard register numbers used for condition codes.\n\
4128	When there is only one such register, as is true on most systems, the\n\
4129	integer pointed to by @var{p2} should be set to\n\
4130	@code{INVALID_REGNUM}.\n\
4131	\n\
4132	The default version of this hook returns false.",
4133	bool, (unsigned int *p1, unsigned int *p2),
4134	hook_bool_uintp_uintp_false)
4135
4136	/* If two condition code modes are compatible, return a condition
4137	code mode which is compatible with both, such that a comparison
4138	done in the returned mode will work for both of the original
4139	modes. If the condition code modes are not compatible, return
4140	VOIDmode. */
4141	DEFHOOK
4142	(cc_modes_compatible,
4143	"On targets which use multiple condition code modes in class\n\
4144	@code{MODE_CC}, it is sometimes the case that a comparison can be\n\
4145	validly done in more than one mode. On such a system, define this\n\
4146	target hook to take two mode arguments and to return a mode in which\n\
4147	both comparisons may be validly done. If there is no such mode,\n\
4148	return @code{VOIDmode}.\n\
4149	\n\
4150	The default version of this hook checks whether the modes are the\n\
4151	same. If they are, it returns that mode. If they are different, it\n\
4152	returns @code{VOIDmode}.",
4153	machine_mode, (machine_mode m1, machine_mode m2),
4154	default_cc_modes_compatible)
4155
4156	DEFHOOK
4157	(use_late_prologue_epilogue,
4158	"Return true if the current function's prologue and epilogue should\n\
4159	be emitted late in the pass pipeline, instead of at the usual point.\n\
4160	\n\
4161	Normally, the prologue and epilogue sequences are introduced soon after\n\
4162	register allocation is complete. The advantage of this approach is that\n\
4163	it allows the prologue and epilogue instructions to be optimized and\n\
4164	scheduled with other code in the function. However, some targets\n\
4165	require the prologue and epilogue to be the first and last sequences\n\
4166	executed by the function, with no variation allowed. This hook should\n\
4167	return true on such targets.\n\
4168	\n\
4169	The default implementation returns false, which is correct for most\n\
4170	targets. The hook should only return true if there is a specific\n\
4171	target limitation that cannot be described in RTL. For example,\n\
4172	the hook might return true if the prologue and epilogue need to switch\n\
4173	between instruction sets.",
4174	bool, (),
4175	hook_bool_void_false)
4176
4177	DEFHOOK
4178	(emit_epilogue_for_sibcall,
4179	"If defined, this hook emits an epilogue sequence for sibling (tail)\n\
4180	call instruction @var{call}. Another way of providing epilogues\n\
4181	for sibling calls is to define the @code{sibcall_epilogue} instruction\n\
4182	pattern; the main advantage of this hook over the pattern is that it\n\
4183	has access to the call instruction.",
4184	void, (rtx_call_insn *call), NULL)
4185
4186	/* Do machine-dependent code transformations. Called just before
4187	delayed-branch scheduling. */
4188	DEFHOOK
4189	(machine_dependent_reorg,
4190	"If non-null, this hook performs a target-specific pass over the\n\
4191	instruction stream. The compiler will run it at all optimization levels,\n\
4192	just before the point at which it normally does delayed-branch scheduling.\n\
4193	\n\
4194	The exact purpose of the hook varies from target to target. Some use\n\
4195	it to do transformations that are necessary for correctness, such as\n\
4196	laying out in-function constant pools or avoiding hardware hazards.\n\
4197	Others use it as an opportunity to do some machine-dependent optimizations.\n\
4198	\n\
4199	You need not implement the hook if it has nothing to do. The default\n\
4200	definition is null.",
4201	void, (void), NULL)
4202
4203	/* Create the __builtin_va_list type. */
4204	DEFHOOK
4205	(build_builtin_va_list,
4206	"This hook returns a type node for @code{va_list} for the target.\n\
4207	The default version of the hook returns @code{void*}.",
4208	tree, (void),
4209	std_build_builtin_va_list)
4210
4211	/* Enumerate the va list variants. */
4212	DEFHOOK
4213	(enum_va_list_p,
4214	"This target hook is used in function @code{c_common_nodes_and_builtins}\n\
4215	to iterate through the target specific builtin types for va_list. The\n\
4216	variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
4217	to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
4218	variable.\n\
4219	The arguments @var{pname} and @var{ptree} are used to store the result of\n\
4220	this macro and are set to the name of the va_list builtin type and its\n\
4221	internal type.\n\
4222	If the return value of this macro is zero, then there is no more element.\n\
4223	Otherwise the @var{IDX} should be increased for the next call of this\n\
4224	macro to iterate through all types.",
4225	int, (int idx, const char **pname, tree *ptree),
4226	NULL)
4227
4228	/* Get the cfun/fndecl calling abi __builtin_va_list type. */
4229	DEFHOOK
4230	(fn_abi_va_list,
4231	"This hook returns the va_list type of the calling convention specified by\n\
4232	@var{fndecl}.\n\
4233	The default version of this hook returns @code{va_list_type_node}.",
4234	tree, (tree fndecl),
4235	std_fn_abi_va_list)
4236
4237	/* Get the __builtin_va_list type dependent on input type. */
4238	DEFHOOK
4239	(canonical_va_list_type,
4240	"This hook returns the va_list type of the calling convention specified by the\n\
4241	type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
4242	@code{NULL_TREE}.",
4243	tree, (tree type),
4244	std_canonical_va_list_type)
4245
4246	/* ??? Documenting this hook requires a GFDL license grant. */
4247	DEFHOOK_UNDOC
4248	(expand_builtin_va_start,
4249	"Expand the @code{__builtin_va_start} builtin.",
4250	void, (tree valist, rtx nextarg), NULL)
4251
4252	/* Gimplifies a VA_ARG_EXPR. */
4253	DEFHOOK
4254	(gimplify_va_arg_expr,
4255	"This hook performs target-specific gimplification of\n\
4256	@code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
4257	arguments to @code{va_arg}; the latter two are as in\n\
4258	@code{gimplify.cc:gimplify_expr}.",
4259	tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
4260	std_gimplify_va_arg_expr)
4261
4262	/* Validity-checking routines for PCH files, target-specific.
4263	get_pch_validity returns a pointer to the data to be stored,
4264	and stores the size in its argument. pch_valid_p gets the same
4265	information back and returns NULL if the PCH is valid,
4266	or an error message if not. */
4267	DEFHOOK
4268	(get_pch_validity,
4269	"This hook returns a pointer to the data needed by\n\
4270	@code{TARGET_PCH_VALID_P} and sets\n\
4271	@samp{*@var{sz}} to the size of the data in bytes.",
4272	void *, (size_t *sz),
4273	default_get_pch_validity)
4274
4275	DEFHOOK
4276	(pch_valid_p,
4277	"This hook checks whether the options used to create a PCH file are\n\
4278	compatible with the current settings. It returns @code{NULL}\n\
4279	if so and a suitable error message if not. Error messages will\n\
4280	be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
4281	\n\
4282	@var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
4283	when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
4284	It's safe to assume that the data was created by the same version of the\n\
4285	compiler, so no format checking is needed.\n\
4286	\n\
4287	The default definition of @code{default_pch_valid_p} should be\n\
4288	suitable for most targets.",
4289	const char *, (const void *data, size_t sz),
4290	default_pch_valid_p)
4291
4292	DEFHOOK
4293	(prepare_pch_save,
4294	"Called before writing out a PCH file. If the target has some\n\
4295	garbage-collected data that needs to be in a particular state on PCH loads,\n\
4296	it can use this hook to enforce that state. Very few targets need\n\
4297	to do anything here.",
4298	void, (void),
4299	hook_void_void)
4300
4301	/* If nonnull, this function checks whether a PCH file with the
4302	given set of target flags can be used. It returns NULL if so,
4303	otherwise it returns an error message. */
4304	DEFHOOK
4305	(check_pch_target_flags,
4306	"If this hook is nonnull, the default implementation of\n\
4307	@code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
4308	of @code{target_flags}. @var{pch_flags} specifies the value that\n\
4309	@code{target_flags} had when the PCH file was created. The return\n\
4310	value is the same as for @code{TARGET_PCH_VALID_P}.",
4311	const char *, (int pch_flags), NULL)
4312
4313	/* True if the compiler should give an enum type only as many
4314	bytes as it takes to represent the range of possible values of
4315	that type. */
4316	DEFHOOK
4317	(default_short_enums,
4318	"This target hook should return true if the compiler should give an\n\
4319	@code{enum} type only as many bytes as it takes to represent the range\n\
4320	of possible values of that type. It should return false if all\n\
4321	@code{enum} types should be allocated like @code{int}.\n\
4322	\n\
4323	The default is to return false.",
4324	bool, (void),
4325	hook_bool_void_false)
4326
4327	/* This target hook returns an rtx that is used to store the address
4328	of the current frame into the built-in setjmp buffer. */
4329	DEFHOOK
4330	(builtin_setjmp_frame_value,
4331	"This target hook should return an rtx that is used to store\n\
4332	the address of the current frame into the built in @code{setjmp} buffer.\n\
4333	The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
4334	machines. One reason you may need to define this target hook is if\n\
4335	@code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
4336	rtx, (void),
4337	default_builtin_setjmp_frame_value)
4338
4339	/* This target hook should manipulate the outputs, inputs, constraints,
4340	and clobbers the port wishes for pre-processing the asm. */
4341	DEFHOOK
4342	(md_asm_adjust,
4343	"This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
4344	@var{clobbered_regs} for any hard regs the port wishes to automatically\n\
4345	clobber for an asm. It can also add hard registers that are used by the\n\
4346	asm to @var{uses}. The @var{outputs} and @var{inputs} may be inspected\n\
4347	to avoid clobbering a register that is already used by the asm. @var{loc}\n\
4348	is the source location of the asm.\n\
4349	\n\
4350	It may modify the @var{outputs}, @var{inputs}, @var{input_modes}, and\n\
4351	@var{constraints} as necessary for other pre-processing. In this case the\n\
4352	return value is a sequence of insns to emit after the asm. Note that\n\
4353	changes to @var{inputs} must be accompanied by the corresponding changes\n\
4354	to @var{input_modes}.",
4355	rtx_insn *,
4356	(vec<rtx>& outputs, vec<rtx>& inputs, vec<machine_mode>& input_modes,
4357	vec<const char *>& constraints, vec<rtx>& usess, vec<rtx>& clobbers,
4358	HARD_REG_SET& clobbered_regs, location_t loc),
4359	NULL)
4360
4361	/* This target hook allows the backend to specify a calling convention
4362	in the debug information. This function actually returns an
4363	enum dwarf_calling_convention, but because of forward declarations
4364	and not wanting to include dwarf2.h everywhere target.h is included
4365	the function is being declared as an int. */
4366	DEFHOOK
4367	(dwarf_calling_convention,
4368	"Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
4369	be emitted for each function. Instead of an integer return the enum\n\
4370	value for the @code{DW_CC_} tag.",
4371	int, (const_tree function),
4372	hook_int_const_tree_0)
4373
4374	/* This target hook allows the backend to emit frame-related insns that
4375	contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
4376	engine will invoke it on insns of the form
4377	(set (reg) (unspec [...] UNSPEC_INDEX))
4378	and
4379	(set (reg) (unspec_volatile [...] UNSPECV_INDEX))
4380	to let the backend emit the call frame instructions. */
4381	DEFHOOK
4382	(dwarf_handle_frame_unspec,
4383	"This target hook allows the backend to emit frame-related insns that\n\
4384	contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
4385	info engine will invoke it on insns of the form\n\
4386	@smallexample\n\
4387	(set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
4388	@end smallexample\n\
4389	and\n\
4390	@smallexample\n\
4391	(set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
4392	@end smallexample\n\
4393	to let the backend emit the call frame instructions. @var{label} is\n\
4394	the CFI label attached to the insn, @var{pattern} is the pattern of\n\
4395	the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
4396	void, (const char *label, rtx pattern, int index), NULL)
4397
4398	DEFHOOK
4399	(dwarf_poly_indeterminate_value,
4400	"Express the value of @code{poly_int} indeterminate @var{i} as a DWARF\n\
4401	expression, with @var{i} counting from 1. Return the number of a DWARF\n\
4402	register @var{R} and set @samp{*@var{factor}} and @samp{*@var{offset}} such\n\
4403	that the value of the indeterminate is:\n\
4404	@smallexample\n\
4405	value_of(@var{R}) / @var{factor} - @var{offset}\n\
4406	@end smallexample\n\
4407	\n\
4408	A target only needs to define this hook if it sets\n\
4409	@samp{NUM_POLY_INT_COEFFS} to a value greater than 1.",
4410	unsigned int, (unsigned int i, unsigned int *factor, int *offset),
4411	default_dwarf_poly_indeterminate_value)
4412
4413	/* ??? Documenting this hook requires a GFDL license grant. */
4414	DEFHOOK_UNDOC
4415	(stdarg_optimize_hook,
4416	"Perform architecture specific checking of statements gimplified\
4417	from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
4418	the statement doesn't need to be checked for @code{va_list} references.",
4419	bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
4420
4421	/* This target hook allows the operating system to override the DECL
4422	that represents the external variable that contains the stack
4423	protection guard variable. The type of this DECL is ptr_type_node. */
4424	DEFHOOK
4425	(stack_protect_guard,
4426	"This hook returns a @code{DECL} node for the external variable to use\n\
4427	for the stack protection guard. This variable is initialized by the\n\
4428	runtime to some random value and is used to initialize the guard value\n\
4429	that is placed at the top of the local stack frame. The type of this\n\
4430	variable must be @code{ptr_type_node}.\n\
4431	\n\
4432	The default version of this hook creates a variable called\n\
4433	@samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
4434	tree, (void),
4435	default_stack_protect_guard)
4436
4437	/* This target hook allows the operating system to override the CALL_EXPR
4438	that is invoked when a check vs the guard variable fails. */
4439	DEFHOOK
4440	(stack_protect_fail,
4441	"This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
4442	stack protect guard variable has been modified. This expression should\n\
4443	involve a call to a @code{noreturn} function.\n\
4444	\n\
4445	The default version of this hook invokes a function called\n\
4446	@samp{__stack_chk_fail}, taking no arguments. This function is\n\
4447	normally defined in @file{libgcc2.c}.",
4448	tree, (void),
4449	default_external_stack_protect_fail)
4450
4451	/* This target hook allows the operating system to disable the default stack
4452	protector runtime support. */
4453	DEFHOOK
4454	(stack_protect_runtime_enabled_p,
4455	"Returns true if the target wants GCC's default stack protect runtime support,\n\
4456	otherwise return false. The default implementation always returns true.",
4457	bool, (void),
4458	hook_bool_void_true)
4459
4460	DEFHOOK
4461	(have_strub_support_for,
4462	"Returns true if the target supports stack scrubbing for the given function\n\
4463	or type, otherwise return false. The default implementation always returns\n\
4464	true.",
4465	bool, (tree),
4466	hook_bool_tree_true)
4467
4468	DEFHOOK
4469	(have_speculation_safe_value,
4470	"This hook is used to determine the level of target support for\n\
4471	@code{__builtin_speculation_safe_value}. If called with an argument\n\
4472	of false, it returns true if the target has been modified to support\n\
4473	this builtin. If called with an argument of true, it returns true\n\
4474	if the target requires active mitigation execution might be speculative.\n\
4475	\n\
4476	The default implementation returns false if the target does not define\n\
4477	a pattern named @code{speculation_barrier}. Else it returns true\n\
4478	for the first case and whether the pattern is enabled for the current\n\
4479	compilation for the second case.\n\
4480	\n\
4481	For targets that have no processors that can execute instructions\n\
4482	speculatively an alternative implemenation of this hook is available:\n\
4483	simply redefine this hook to @code{speculation_safe_value_not_needed}\n\
4484	along with your other target hooks.",
4485	bool, (bool active), default_have_speculation_safe_value)
4486
4487	DEFHOOK
4488	(speculation_safe_value,
4489	"This target hook can be used to generate a target-specific code\n\
4490	sequence that implements the @code{__builtin_speculation_safe_value}\n\
4491	built-in function. The function must always return @var{val} in\n\
4492	@var{result} in mode @var{mode} when the cpu is not executing\n\
4493	speculatively, but must never return that when speculating until it\n\
4494	is known that the speculation will not be unwound. The hook supports\n\
4495	two primary mechanisms for implementing the requirements. The first\n\
4496	is to emit a speculation barrier which forces the processor to wait\n\
4497	until all prior speculative operations have been resolved; the second\n\
4498	is to use a target-specific mechanism that can track the speculation\n\
4499	state and to return @var{failval} if it can determine that\n\
4500	speculation must be unwound at a later time.\n\
4501	\n\
4502	The default implementation simply copies @var{val} to @var{result} and\n\
4503	emits a @code{speculation_barrier} instruction if that is defined.",
4504	rtx, (machine_mode mode, rtx result, rtx val, rtx failval),
4505	default_speculation_safe_value)
4506
4507	DEFHOOK
4508	(predict_doloop_p,
4509	"Return true if we can predict it is possible to use a low-overhead loop\n\
4510	for a particular loop. The parameter @var{loop} is a pointer to the loop.\n\
4511	This target hook is required only when the target supports low-overhead\n\
4512	loops, and will help ivopts to make some decisions.\n\
4513	The default version of this hook returns false.",
4514	bool, (class loop *loop),
4515	default_predict_doloop_p)
4516
4517	DEFHOOKPOD
4518	(have_count_reg_decr_p,
4519	"Return true if the target supports hardware count register for decrement\n\
4520	and branch.\n\
4521	The default value is false.",
4522	bool, false)
4523
4524	DEFHOOKPOD
4525	(doloop_cost_for_generic,
4526	"One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4527	calculate the computation cost of adopting it to any generic IV use by\n\
4528	function get_computation_cost as before. But for targets which have\n\
4529	hardware count register support for decrement and branch, it may have to\n\
4530	move IV value from hardware count register to general purpose register\n\
4531	while doloop IV candidate is used for generic IV uses. It probably takes\n\
4532	expensive penalty. This hook allows target owners to define the cost for\n\
4533	this especially for generic IV uses.\n\
4534	The default value is zero.",
4535	int64_t, 0)
4536
4537	DEFHOOKPOD
4538	(doloop_cost_for_address,
4539	"One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4540	calculate the computation cost of adopting it to any address IV use by\n\
4541	function get_computation_cost as before. But for targets which have\n\
4542	hardware count register support for decrement and branch, it may have to\n\
4543	move IV value from hardware count register to general purpose register\n\
4544	while doloop IV candidate is used for address IV uses. It probably takes\n\
4545	expensive penalty. This hook allows target owners to define the cost for\n\
4546	this escpecially for address IV uses.\n\
4547	The default value is zero.",
4548	int64_t, 0)
4549
4550	DEFHOOK
4551	(can_use_doloop_p,
4552	"Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
4553	and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
4554	exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
4555	the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
4556	the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
4557	contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
4558	loop is only entered from the top.\n\
4559	\n\
4560	This hook is only used if @code{doloop_end} is available. The default\n\
4561	implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
4562	if the loop must be the innermost, and if there are no other restrictions.",
4563	bool, (const widest_int &iterations, const widest_int &iterations_max,
4564	unsigned int loop_depth, bool entered_at_top),
4565	hook_bool_wint_wint_uint_bool_true)
4566
4567	/* Returns NULL if target supports the insn within a doloop block,
4568	otherwise it returns an error message. */
4569	DEFHOOK
4570	(invalid_within_doloop,
4571	"\n\
4572	Take an instruction in @var{insn} and return NULL if it is valid within a\n\
4573	low-overhead loop, otherwise return a string explaining why doloop\n\
4574	could not be applied.\n\
4575	\n\
4576	Many targets use special registers for low-overhead looping. For any\n\
4577	instruction that clobbers these this function should return a string indicating\n\
4578	the reason why the doloop could not be applied.\n\
4579	By default, the RTL loop optimizer does not use a present doloop pattern for\n\
4580	loops containing function calls or branch on table instructions.",
4581	const char *, (const rtx_insn *insn),
4582	default_invalid_within_doloop)
4583
4584	/* Returns the machine mode which the target prefers for doloop IV. */
4585	DEFHOOK
4586	(preferred_doloop_mode,
4587	"This hook takes a @var{mode} for a doloop IV, where @code{mode} is the\n\
4588	original mode for the operation. If the target prefers an alternate\n\
4589	@code{mode} for the operation, then this hook should return that mode;\n\
4590	otherwise the original @code{mode} should be returned. For example, on a\n\
4591	64-bit target, @code{DImode} might be preferred over @code{SImode}. Both the\n\
4592	original and the returned modes should be @code{MODE_INT}.",
4593	machine_mode,
4594	(machine_mode mode),
4595	default_preferred_doloop_mode)
4596
4597	/* Returns true for a legitimate combined insn. */
4598	DEFHOOK
4599	(legitimate_combined_insn,
4600	"Take an instruction in @var{insn} and return @code{false} if the instruction\n\
4601	is not appropriate as a combination of two or more instructions. The\n\
4602	default is to accept all instructions.",
4603	bool, (rtx_insn *insn),
4604	hook_bool_rtx_insn_true)
4605
4606	DEFHOOK
4607	(valid_dllimport_attribute_p,
4608	"@var{decl} is a variable or function with @code{__attribute__((dllimport))}\n\
4609	specified. Use this hook if the target needs to add extra validation\n\
4610	checks to @code{handle_dll_attribute}.",
4611	bool, (const_tree decl),
4612	hook_bool_const_tree_true)
4613
4614	/* If non-zero, align constant anchors in CSE to a multiple of this
4615	value. */
4616	DEFHOOKPOD
4617	(const_anchor,
4618	"On some architectures it can take multiple instructions to synthesize\n\
4619	a constant. If there is another constant already in a register that\n\
4620	is close enough in value then it is preferable that the new constant\n\
4621	is computed from this register using immediate addition or\n\
4622	subtraction. We accomplish this through CSE. Besides the value of\n\
4623	the constant we also add a lower and an upper constant anchor to the\n\
4624	available expressions. These are then queried when encountering new\n\
4625	constants. The anchors are computed by rounding the constant up and\n\
4626	down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
4627	@code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
4628	accepted by immediate-add plus one. We currently assume that the\n\
4629	value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
4630	MIPS, where add-immediate takes a 16-bit signed value,\n\
4631	@code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
4632	is zero, which disables this optimization.",
4633	unsigned HOST_WIDE_INT, 0)
4634
4635	/* Defines, which target-dependent bits (upper 16) are used by port */
4636	DEFHOOK
4637	(memmodel_check,
4638	"Validate target specific memory model mask bits. When NULL no target specific\n\
4639	memory model bits are allowed.",
4640	unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4641
4642	/* Defines an offset bitwise ored into shifted address to get corresponding
4643	Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4644	supported by the target. */
4645	DEFHOOK
4646	(asan_shadow_offset,
4647	"Return the offset bitwise ored into shifted address to get corresponding\n\
4648	Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4649	supported by the target. May return 0 if Address Sanitizer is not supported\n\
4650	by a subtarget.",
4651	unsigned HOST_WIDE_INT, (void),
4652	NULL)
4653
4654	/* Functions relating to calls - argument passing, returns, etc. */
4655	/* Members of struct call have no special macro prefix. */
4656	HOOK_VECTOR (TARGET_CALLS, calls)
4657
4658	DEFHOOK
4659	(promote_function_mode,
4660	"Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4661	function return values. The target hook should return the new mode\n\
4662	and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4663	change signedness. This function is called only for scalar @emph{or\n\
4664	pointer} types.\n\
4665	\n\
4666	@var{for_return} allows to distinguish the promotion of arguments and\n\
4667	return values. If it is @code{1}, a return value is being promoted and\n\
4668	@code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4669	If it is @code{2}, the returned mode should be that of the register in\n\
4670	which an incoming parameter is copied, or the outgoing result is computed;\n\
4671	then the hook should return the same mode as @code{promote_mode}, though\n\
4672	the signedness may be different.\n\
4673	\n\
4674	@var{type} can be NULL when promoting function arguments of libcalls.\n\
4675	\n\
4676	The default is to not promote arguments and return values. You can\n\
4677	also define the hook to @code{default_promote_function_mode_always_promote}\n\
4678	if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4679	machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4680	const_tree funtype, int for_return),
4681	default_promote_function_mode)
4682
4683	DEFHOOK
4684	(promote_prototypes,
4685	"This target hook returns @code{true} if an argument declared in a\n\
4686	prototype as an integral type smaller than @code{int} should actually be\n\
4687	passed as an @code{int}. In addition to avoiding errors in certain\n\
4688	cases of mismatch, it also makes for better code on certain machines.\n\
4689	The default is to not promote prototypes.",
4690	bool, (const_tree fntype),
4691	hook_bool_const_tree_false)
4692
4693	DEFHOOK
4694	(struct_value_rtx,
4695	"This target hook should return the location of the structure value\n\
4696	address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4697	passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4698	be @code{NULL}, for libcalls. You do not need to define this target\n\
4699	hook if the address is always passed as an ``invisible'' first\n\
4700	argument.\n\
4701	\n\
4702	On some architectures the place where the structure value address\n\
4703	is found by the called function is not the same place that the\n\
4704	caller put it. This can be due to register windows, or it could\n\
4705	be because the function prologue moves it to a different place.\n\
4706	@var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4707	the context of the called function, and @code{0} in the context of\n\
4708	the caller.\n\
4709	\n\
4710	If @var{incoming} is nonzero and the address is to be found on the\n\
4711	stack, return a @code{mem} which refers to the frame pointer. If\n\
4712	@var{incoming} is @code{2}, the result is being used to fetch the\n\
4713	structure value address at the beginning of a function. If you need\n\
4714	to emit adjusting code, you should do it at this point.",
4715	rtx, (tree fndecl, int incoming),
4716	hook_rtx_tree_int_null)
4717
4718	DEFHOOKPOD
4719	(omit_struct_return_reg,
4720	"Normally, when a function returns a structure by memory, the address\n\
4721	is passed as an invisible pointer argument, but the compiler also\n\
4722	arranges to return the address from the function like it would a normal\n\
4723	pointer return value. Define this to true if that behavior is\n\
4724	undesirable on your target.",
4725	bool, false)
4726
4727	DEFHOOK
4728	(return_in_memory,
4729	"This target hook should return a nonzero value to say to return the\n\
4730	function value in memory, just as large structures are always returned.\n\
4731	Here @var{type} will be the data type of the value, and @var{fntype}\n\
4732	will be the type of the function doing the returning, or @code{NULL} for\n\
4733	libcalls.\n\
4734	\n\
4735	Note that values of mode @code{BLKmode} must be explicitly handled\n\
4736	by this function. Also, the option @option{-fpcc-struct-return}\n\
4737	takes effect regardless of this macro. On most systems, it is\n\
4738	possible to leave the hook undefined; this causes a default\n\
4739	definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4740	values, and 0 otherwise.\n\
4741	\n\
4742	Do not use this hook to indicate that structures and unions should always\n\
4743	be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4744	to indicate this.",
4745	bool, (const_tree type, const_tree fntype),
4746	default_return_in_memory)
4747
4748	DEFHOOK
4749	(return_in_msb,
4750	"This hook should return true if values of type @var{type} are returned\n\
4751	at the most significant end of a register (in other words, if they are\n\
4752	padded at the least significant end). You can assume that @var{type}\n\
4753	is returned in a register; the caller is required to check this.\n\
4754	\n\
4755	Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4756	be able to hold the complete return value. For example, if a 1-, 2-\n\
4757	or 3-byte structure is returned at the most significant end of a\n\
4758	4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4759	@code{SImode} rtx.",
4760	bool, (const_tree type),
4761	hook_bool_const_tree_false)
4762
4763	/* Return true if a parameter must be passed by reference. TYPE may
4764	be null if this is a libcall. CA may be null if this query is
4765	from __builtin_va_arg. */
4766	DEFHOOK
4767	(pass_by_reference,
4768	"This target hook should return @code{true} if argument @var{arg} at the\n\
4769	position indicated by @var{cum} should be passed by reference. This\n\
4770	predicate is queried after target independent reasons for being\n\
4771	passed by reference, such as @code{TREE_ADDRESSABLE (@var{arg}.type)}.\n\
4772	\n\
4773	If the hook returns true, a copy of that argument is made in memory and a\n\
4774	pointer to the argument is passed instead of the argument itself.\n\
4775	The pointer is passed in whatever way is appropriate for passing a pointer\n\
4776	to that type.",
4777	bool,
4778	(cumulative_args_t cum, const function_arg_info &arg),
4779	hook_bool_CUMULATIVE_ARGS_arg_info_false)
4780
4781	DEFHOOK
4782	(expand_builtin_saveregs,
4783	"If defined, this hook produces the machine-specific code for a call to\n\
4784	@code{__builtin_saveregs}. This code will be moved to the very\n\
4785	beginning of the function, before any parameter access are made. The\n\
4786	return value of this function should be an RTX that contains the value\n\
4787	to use as the return of @code{__builtin_saveregs}.",
4788	rtx, (void),
4789	default_expand_builtin_saveregs)
4790
4791	/* Returns pretend_argument_size. */
4792	DEFHOOK
4793	(setup_incoming_varargs,
4794	"This target hook offers an alternative to using\n\
4795	@code{__builtin_saveregs} and defining the hook\n\
4796	@code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4797	register arguments into the stack so that all the arguments appear to\n\
4798	have been passed consecutively on the stack. Once this is done, you can\n\
4799	use the standard implementation of varargs that works for machines that\n\
4800	pass all their arguments on the stack.\n\
4801	\n\
4802	The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4803	structure, containing the values that are obtained after processing the\n\
4804	named arguments. The argument @var{arg} describes the last of these named\n\
4805	arguments. The argument @var{arg} should not be used if the function type\n\
4806	satisfies @code{TYPE_NO_NAMED_ARGS_STDARG_P}, since in that case there are\n\
4807	no named arguments and all arguments are accessed with @code{va_arg}.\n\
4808	\n\
4809	The target hook should do two things: first, push onto the stack all the\n\
4810	argument registers @emph{not} used for the named arguments, and second,\n\
4811	store the size of the data thus pushed into the @code{int}-valued\n\
4812	variable pointed to by @var{pretend_args_size}. The value that you\n\
4813	store here will serve as additional offset for setting up the stack\n\
4814	frame.\n\
4815	\n\
4816	Because you must generate code to push the anonymous arguments at\n\
4817	compile time without knowing their data types,\n\
4818	@code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4819	have just a single category of argument register and use it uniformly\n\
4820	for all data types.\n\
4821	\n\
4822	If the argument @var{second_time} is nonzero, it means that the\n\
4823	arguments of the function are being analyzed for the second time. This\n\
4824	happens for an inline function, which is not actually compiled until the\n\
4825	end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4826	not generate any instructions in this case.",
4827	void, (cumulative_args_t args_so_far, const function_arg_info &arg,
4828	int *pretend_args_size, int second_time),
4829	default_setup_incoming_varargs)
4830
4831	DEFHOOK
4832	(start_call_args,
4833	"This target hook is invoked while generating RTL for a function call,\n\
4834	after the argument values have been computed, and after stack arguments\n\
4835	have been initialized, but before register arguments have been moved into\n\
4836	their ABI-defined hard register locations. It precedes calls to the related\n\
4837	hooks @code{TARGET_CALL_ARGS} and @code{TARGET_END_CALL_ARGS}.\n\
4838	The significance of this position in the call expansion is that:\n\
4839	\n\
4840	@itemize @bullet\n\
4841	@item\n\
4842	No argument registers are live.\n\
4843	@item\n\
4844	Although a call sequence can in general involve subcalls (such as using\n\
4845	@code{memcpy} to copy large arguments), no such subcall will occur between\n\
4846	the call to this hook and the generation of the main call instruction.\n\
4847	@end itemize\n\
4848	\n\
4849	The single argument @var{complete_args} is the state of the target\n\
4850	function's cumulative argument information after the final call to\n\
4851	@code{TARGET_FUNCTION_ARG}.\n\
4852	\n\
4853	The hook can be used for things like switching processor mode, in cases\n\
4854	where different calls need different processor modes. Most ports do not\n\
4855	need to implement anything for this hook.",
4856	void, (cumulative_args_t complete_args),
4857	hook_void_CUMULATIVE_ARGS)
4858
4859	DEFHOOK
4860	(call_args,
4861	"While generating RTL for a function call, this target hook is invoked once\n\
4862	for each argument passed to the function, either a register returned by\n\
4863	@code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4864	before the point where argument registers are stored.\n\
4865	\n\
4866	@var{complete_args} is the state of the target function's cumulative\n\
4867	argument information after the final call to @code{TARGET_FUNCTION_ARG}.\n\
4868	@var{loc} is the location of the argument. @var{type} is the type of\n\
4869	the function being called, or @code{NULL_TREE} for libcalls.\n\
4870	\n\
4871	For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4872	passed instead of an argument register.\n\
4873	\n\
4874	This functionality can be used to perform special setup of call argument\n\
4875	registers, if a target needs it. Most ports do not need to implement\n\
4876	anything for this hook.",
4877	void, (cumulative_args_t complete_args, rtx loc, tree type),
4878	hook_void_CUMULATIVE_ARGS_rtx_tree)
4879
4880	DEFHOOK
4881	(end_call_args,
4882	"This target hook is invoked while generating RTL for a function call,\n\
4883	just after the point where the return reg is copied into a pseudo. It\n\
4884	signals that all the call argument and return registers for the just\n\
4885	emitted call are now no longer in use. @var{complete_args} is the\n\
4886	state of the target function's cumulative argument information after\n\
4887	the final call to @code{TARGET_FUNCTION_ARG}.\n\
4888	\n\
4889	Most ports do not need to implement anything for this hook.",
4890	void, (cumulative_args_t complete_args),
4891	hook_void_CUMULATIVE_ARGS)
4892
4893	DEFHOOK
4894	(push_argument,
4895	"This target hook returns @code{true} if push instructions will be\n\
4896	used to pass outgoing arguments. When the push instruction usage is\n\
4897	optional, @var{npush} is nonzero to indicate the number of bytes to\n\
4898	push. Otherwise, @var{npush} is zero. If the target machine does not\n\
4899	have a push instruction or push instruction should be avoided,\n\
4900	@code{false} should be returned. That directs GCC to use an alternate\n\
4901	strategy: to allocate the entire argument block and then store the\n\
4902	arguments into it. If this target hook may return @code{true},\n\
4903	@code{PUSH_ROUNDING} must be defined.",
4904	bool, (unsigned int npush),
4905	default_push_argument)
4906
4907	DEFHOOK
4908	(strict_argument_naming,
4909	"Define this hook to return @code{true} if the location where a function\n\
4910	argument is passed depends on whether or not it is a named argument.\n\
4911	\n\
4912	This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4913	is set for varargs and stdarg functions. If this hook returns\n\
4914	@code{true}, the @var{named} argument is always true for named\n\
4915	arguments, and false for unnamed arguments. If it returns @code{false},\n\
4916	but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4917	then all arguments are treated as named. Otherwise, all named arguments\n\
4918	except the last are treated as named.\n\
4919	\n\
4920	You need not define this hook if it always returns @code{false}.",
4921	bool, (cumulative_args_t ca),
4922	hook_bool_CUMULATIVE_ARGS_false)
4923
4924	/* Returns true if we should use
4925	targetm.calls.setup_incoming_varargs() and/or
4926	targetm.calls.strict_argument_naming(). */
4927	DEFHOOK
4928	(pretend_outgoing_varargs_named,
4929	"If you need to conditionally change ABIs so that one works with\n\
4930	@code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4931	@code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4932	defined, then define this hook to return @code{true} if\n\
4933	@code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4934	Otherwise, you should not define this hook.",
4935	bool, (cumulative_args_t ca),
4936	default_pretend_outgoing_varargs_named)
4937
4938	/* Given a complex type T, return true if a parameter of type T
4939	should be passed as two scalars. */
4940	DEFHOOK
4941	(split_complex_arg,
4942	"This hook should return true if parameter of type @var{type} are passed\n\
4943	as two scalar parameters. By default, GCC will attempt to pack complex\n\
4944	arguments into the target's word size. Some ABIs require complex arguments\n\
4945	to be split and treated as their individual components. For example, on\n\
4946	AIX64, complex floats should be passed in a pair of floating point\n\
4947	registers, even though a complex float would fit in one 64-bit floating\n\
4948	point register.\n\
4949	\n\
4950	The default value of this hook is @code{NULL}, which is treated as always\n\
4951	false.",
4952	bool, (const_tree type), NULL)
4953
4954	/* Return true if type T, mode MODE, may not be passed in registers,
4955	but must be passed on the stack. */
4956	/* ??? This predicate should be applied strictly after pass-by-reference.
4957	Need audit to verify that this is the case. */
4958	DEFHOOK
4959	(must_pass_in_stack,
4960	"This target hook should return @code{true} if we should not pass @var{arg}\n\
4961	solely in registers. The file @file{expr.h} defines a\n\
4962	definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4963	documentation.",
4964	bool, (const function_arg_info &arg),
4965	must_pass_in_stack_var_size_or_pad)
4966
4967	/* Return true if type TYPE, mode MODE, which is passed by reference,
4968	should have the object copy generated by the callee rather than
4969	the caller. It is never called for TYPE requiring constructors. */
4970	DEFHOOK
4971	(callee_copies,
4972	"The function argument described by the parameters to this hook is\n\
4973	known to be passed by reference. The hook should return true if the\n\
4974	function argument should be copied by the callee instead of copied\n\
4975	by the caller.\n\
4976	\n\
4977	For any argument for which the hook returns true, if it can be\n\
4978	determined that the argument is not modified, then a copy need\n\
4979	not be generated.\n\
4980	\n\
4981	The default version of this hook always returns false.",
4982	bool,
4983	(cumulative_args_t cum, const function_arg_info &arg),
4984	hook_bool_CUMULATIVE_ARGS_arg_info_false)
4985
4986	/* Return zero for arguments passed entirely on the stack or entirely
4987	in registers. If passed in both, return the number of bytes passed
4988	in registers; the balance is therefore passed on the stack. */
4989	DEFHOOK
4990	(arg_partial_bytes,
4991	"This target hook returns the number of bytes at the beginning of an\n\
4992	argument that must be put in registers. The value must be zero for\n\
4993	arguments that are passed entirely in registers or that are entirely\n\
4994	pushed on the stack.\n\
4995	\n\
4996	On some machines, certain arguments must be passed partially in\n\
4997	registers and partially in memory. On these machines, typically the\n\
4998	first few words of arguments are passed in registers, and the rest\n\
4999	on the stack. If a multi-word argument (a @code{double} or a\n\
5000	structure) crosses that boundary, its first few words must be passed\n\
5001	in registers and the rest must be pushed. This macro tells the\n\
5002	compiler when this occurs, and how many bytes should go in registers.\n\
5003	\n\
5004	@code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
5005	register to be used by the caller for this argument; likewise\n\
5006	@code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
5007	int, (cumulative_args_t cum, const function_arg_info &arg),
5008	hook_int_CUMULATIVE_ARGS_arg_info_0)
5009
5010	/* Update the state in CA to advance past an argument in the
5011	argument list. The values MODE, TYPE, and NAMED describe that
5012	argument. */
5013	DEFHOOK
5014	(function_arg_advance,
5015	"This hook updates the summarizer variable pointed to by @var{ca} to\n\
5016	advance past argument @var{arg} in the argument list. Once this is done,\n\
5017	the variable @var{cum} is suitable for analyzing the @emph{following}\n\
5018	argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
5019	\n\
5020	This hook need not do anything if the argument in question was passed\n\
5021	on the stack. The compiler knows how to track the amount of stack space\n\
5022	used for arguments without any special help.",
5023	void,
5024	(cumulative_args_t ca, const function_arg_info &arg),
5025	default_function_arg_advance)
5026
5027	DEFHOOK
5028	(function_arg_offset,
5029	"This hook returns the number of bytes to add to the offset of an\n\
5030	argument of type @var{type} and mode @var{mode} when passed in memory.\n\
5031	This is needed for the SPU, which passes @code{char} and @code{short}\n\
5032	arguments in the preferred slot that is in the middle of the quad word\n\
5033	instead of starting at the top. The default implementation returns 0.",
5034	HOST_WIDE_INT, (machine_mode mode, const_tree type),
5035	default_function_arg_offset)
5036
5037	DEFHOOK
5038	(function_arg_padding,
5039	"This hook determines whether, and in which direction, to pad out\n\
5040	an argument of mode @var{mode} and type @var{type}. It returns\n\
5041	@code{PAD_UPWARD} to insert padding above the argument, @code{PAD_DOWNWARD}\n\
5042	to insert padding below the argument, or @code{PAD_NONE} to inhibit padding.\n\
5043	\n\
5044	The @emph{amount} of padding is not controlled by this hook, but by\n\
5045	@code{TARGET_FUNCTION_ARG_ROUND_BOUNDARY}. It is always just enough\n\
5046	to reach the next multiple of that boundary.\n\
5047	\n\
5048	This hook has a default definition that is right for most systems.\n\
5049	For little-endian machines, the default is to pad upward. For\n\
5050	big-endian machines, the default is to pad downward for an argument of\n\
5051	constant size shorter than an @code{int}, and upward otherwise.",
5052	pad_direction, (machine_mode mode, const_tree type),
5053	default_function_arg_padding)
5054
5055	/* Return zero if the argument described by the state of CA should
5056	be placed on a stack, or a hard register in which to store the
5057	argument. The values MODE, TYPE, and NAMED describe that
5058	argument. */
5059	DEFHOOK
5060	(function_arg,
5061	"Return an RTX indicating whether function argument @var{arg} is passed\n\
5062	in a register and if so, which register. Argument @var{ca} summarizes all\n\
5063	the previous arguments.\n\
5064	\n\
5065	The return value is usually either a @code{reg} RTX for the hard\n\
5066	register in which to pass the argument, or zero to pass the argument\n\
5067	on the stack.\n\
5068	\n\
5069	The value of the expression can also be a @code{parallel} RTX@. This is\n\
5070	used when an argument is passed in multiple locations. The mode of the\n\
5071	@code{parallel} should be the mode of the entire argument. The\n\
5072	@code{parallel} holds any number of @code{expr_list} pairs; each one\n\
5073	describes where part of the argument is passed. In each\n\
5074	@code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
5075	register in which to pass this part of the argument, and the mode of the\n\
5076	register RTX indicates how large this part of the argument is. The\n\
5077	second operand of the @code{expr_list} is a @code{const_int} which gives\n\
5078	the offset in bytes into the entire argument of where this part starts.\n\
5079	As a special exception the first @code{expr_list} in the @code{parallel}\n\
5080	RTX may have a first operand of zero. This indicates that the entire\n\
5081	argument is also stored on the stack.\n\
5082	\n\
5083	The last time this hook is called, it is called with @code{MODE ==\n\
5084	VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
5085	pattern as operands 2 and 3 respectively.\n\
5086	\n\
5087	@cindex @file{stdarg.h} and register arguments\n\
5088	The usual way to make the ISO library @file{stdarg.h} work on a\n\
5089	machine where some arguments are usually passed in registers, is to\n\
5090	cause nameless arguments to be passed on the stack instead. This is\n\
5091	done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
5092	@var{named} is @code{false}.\n\
5093	\n\
5094	@cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
5095	@cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
5096	You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
5097	in the definition of this macro to determine if this argument is of a\n\
5098	type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
5099	is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
5100	argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
5101	defined, the argument will be computed in the stack and then loaded into\n\
5102	a register.",
5103	rtx, (cumulative_args_t ca, const function_arg_info &arg),
5104	default_function_arg)
5105
5106	DEFHOOK
5107	(function_incoming_arg,
5108	"Define this hook if the caller and callee on the target have different\n\
5109	views of where arguments are passed. Also define this hook if there are\n\
5110	functions that are never directly called, but are invoked by the hardware\n\
5111	and which have nonstandard calling conventions.\n\
5112	\n\
5113	In this case @code{TARGET_FUNCTION_ARG} computes the register in\n\
5114	which the caller passes the value, and\n\
5115	@code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
5116	fashion to tell the function being called where the arguments will\n\
5117	arrive.\n\
5118	\n\
5119	@code{TARGET_FUNCTION_INCOMING_ARG} can also return arbitrary address\n\
5120	computation using hard register, which can be forced into a register,\n\
5121	so that it can be used to pass special arguments.\n\
5122	\n\
5123	If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
5124	@code{TARGET_FUNCTION_ARG} serves both purposes.",
5125	rtx, (cumulative_args_t ca, const function_arg_info &arg),
5126	default_function_incoming_arg)
5127
5128	DEFHOOK
5129	(function_arg_boundary,
5130	"This hook returns the alignment boundary, in bits, of an argument\n\
5131	with the specified mode and type. The default hook returns\n\
5132	@code{PARM_BOUNDARY} for all arguments.",
5133	unsigned int, (machine_mode mode, const_tree type),
5134	default_function_arg_boundary)
5135
5136	DEFHOOK
5137	(function_arg_round_boundary,
5138	"Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
5139	which is the default value for this hook. You can define this hook to\n\
5140	return a different value if an argument size must be rounded to a larger\n\
5141	value.",
5142	unsigned int, (machine_mode mode, const_tree type),
5143	default_function_arg_round_boundary)
5144
5145	/* Return the diagnostic message string if function without a prototype
5146	is not allowed for this 'val' argument; NULL otherwise. */
5147	DEFHOOK
5148	(invalid_arg_for_unprototyped_fn,
5149	"If defined, this macro returns the diagnostic message when it is\n\
5150	illegal to pass argument @var{val} to function @var{funcdecl}\n\
5151	with prototype @var{typelist}.",
5152	const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
5153	hook_invalid_arg_for_unprototyped_fn)
5154
5155	/* Return an rtx for the return value location of the function
5156	specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
5157	DEFHOOK
5158	(function_value,
5159	"\n\
5160	Define this to return an RTX representing the place where a function\n\
5161	returns or receives a value of data type @var{ret_type}, a tree node\n\
5162	representing a data type. @var{fn_decl_or_type} is a tree node\n\
5163	representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
5164	function being called. If @var{outgoing} is false, the hook should\n\
5165	compute the register in which the caller will see the return value.\n\
5166	Otherwise, the hook should return an RTX representing the place where\n\
5167	a function returns a value.\n\
5168	\n\
5169	On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
5170	(Actually, on most machines, scalar values are returned in the same\n\
5171	place regardless of mode.) The value of the expression is usually a\n\
5172	@code{reg} RTX for the hard register where the return value is stored.\n\
5173	The value can also be a @code{parallel} RTX, if the return value is in\n\
5174	multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
5175	@code{parallel} form. Note that the callee will populate every\n\
5176	location specified in the @code{parallel}, but if the first element of\n\
5177	the @code{parallel} contains the whole return value, callers will use\n\
5178	that element as the canonical location and ignore the others. The m68k\n\
5179	port uses this type of @code{parallel} to return pointers in both\n\
5180	@samp{%a0} (the canonical location) and @samp{%d0}.\n\
5181	\n\
5182	If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
5183	the same promotion rules specified in @code{PROMOTE_MODE} if\n\
5184	@var{valtype} is a scalar type.\n\
5185	\n\
5186	If the precise function being called is known, @var{func} is a tree\n\
5187	node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
5188	pointer. This makes it possible to use a different value-returning\n\
5189	convention for specific functions when all their calls are\n\
5190	known.\n\
5191	\n\
5192	Some target machines have ``register windows'' so that the register in\n\
5193	which a function returns its value is not the same as the one in which\n\
5194	the caller sees the value. For such machines, you should return\n\
5195	different RTX depending on @var{outgoing}.\n\
5196	\n\
5197	@code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
5198	aggregate data types, because these are returned in another way. See\n\
5199	@code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
5200	rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
5201	default_function_value)
5202
5203	/* Return the rtx for the result of a libcall of mode MODE,
5204	calling the function FN_NAME. */
5205	DEFHOOK
5206	(libcall_value,
5207	"Define this hook if the back-end needs to know the name of the libcall\n\
5208	function in order to determine where the result should be returned.\n\
5209	\n\
5210	The mode of the result is given by @var{mode} and the name of the called\n\
5211	library function is given by @var{fun}. The hook should return an RTX\n\
5212	representing the place where the library function result will be returned.\n\
5213	\n\
5214	If this hook is not defined, then LIBCALL_VALUE will be used.",
5215	rtx, (machine_mode mode, const_rtx fun),
5216	default_libcall_value)
5217
5218	/* Return true if REGNO is a possible register number for
5219	a function value as seen by the caller. */
5220	DEFHOOK
5221	(function_value_regno_p,
5222	"A target hook that return @code{true} if @var{regno} is the number of a hard\n\
5223	register in which the values of called function may come back.\n\
5224	\n\
5225	A register whose use for returning values is limited to serving as the\n\
5226	second of a pair (for a value of type @code{double}, say) need not be\n\
5227	recognized by this target hook.\n\
5228	\n\
5229	If the machine has register windows, so that the caller and the called\n\
5230	function use different registers for the return value, this target hook\n\
5231	should recognize only the caller's register numbers.\n\
5232	\n\
5233	If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
5234	bool, (const unsigned int regno),
5235	default_function_value_regno_p)
5236
5237	DEFHOOK
5238	(fntype_abi,
5239	"Return the ABI used by a function with type @var{type}; see the\n\
5240	definition of @code{predefined_function_abi} for details of the ABI\n\
5241	descriptor. Targets only need to define this hook if they support\n\
5242	interoperability between several ABIs in the same translation unit.",
5243	const predefined_function_abi &, (const_tree type),
5244	NULL)
5245
5246	DEFHOOK
5247	(insn_callee_abi,
5248	"This hook returns a description of the ABI used by the target of\n\
5249	call instruction @var{insn}; see the definition of\n\
5250	@code{predefined_function_abi} for details of the ABI descriptor.\n\
5251	Only the global function @code{insn_callee_abi} should call this hook\n\
5252	directly.\n\
5253	\n\
5254	Targets only need to define this hook if they support\n\
5255	interoperability between several ABIs in the same translation unit.",
5256	const predefined_function_abi &, (const rtx_insn *insn),
5257	NULL)
5258
5259	/* ??? Documenting this hook requires a GFDL license grant. */
5260	DEFHOOK_UNDOC
5261	(internal_arg_pointer,
5262	"Return an rtx for the argument pointer incoming to the\
5263	current function.",
5264	rtx, (void),
5265	default_internal_arg_pointer)
5266
5267	/* Update the current function stack boundary if needed. */
5268	DEFHOOK
5269	(update_stack_boundary,
5270	"Define this macro to update the current function stack boundary if\n\
5271	necessary.",
5272	void, (void), NULL)
5273
5274	/* Handle stack alignment and return an rtx for Dynamic Realign
5275	Argument Pointer if necessary. */
5276	DEFHOOK
5277	(get_drap_rtx,
5278	"This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
5279	different argument pointer register is needed to access the function's\n\
5280	argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
5281	is needed.",
5282	rtx, (void), NULL)
5283
5284	/* Generate instruction sequence to zero call used registers. */
5285	DEFHOOK
5286	(zero_call_used_regs,
5287	"This target hook emits instructions to zero the subset of @var{selected_regs}\n\
5288	that could conceivably contain values that are useful to an attacker.\n\
5289	Return the set of registers that were actually cleared.\n\
5290	\n\
5291	For most targets, the returned set of registers is a subset of\n\
5292	@var{selected_regs}, however, for some of the targets (for example MIPS),\n\
5293	clearing some registers that are in the @var{selected_regs} requires\n\
5294	clearing other call used registers that are not in the @var{selected_regs},\n\
5295	under such situation, the returned set of registers must be a subset of all\n\
5296	call used registers.\n\
5297	\n\
5298	The default implementation uses normal move instructions to zero\n\
5299	all the registers in @var{selected_regs}. Define this hook if the\n\
5300	target has more efficient ways of zeroing certain registers,\n\
5301	or if you believe that certain registers would never contain\n\
5302	values that are useful to an attacker.",
5303	HARD_REG_SET, (HARD_REG_SET selected_regs),
5304	default_zero_call_used_regs)
5305
5306	/* Return true if all function parameters should be spilled to the
5307	stack. */
5308	DEFHOOK
5309	(allocate_stack_slots_for_args,
5310	"When optimization is disabled, this hook indicates whether or not\n\
5311	arguments should be allocated to stack slots. Normally, GCC allocates\n\
5312	stacks slots for arguments when not optimizing in order to make\n\
5313	debugging easier. However, when a function is declared with\n\
5314	@code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
5315	cannot safely move arguments from the registers in which they are passed\n\
5316	to the stack. Therefore, this hook should return true in general, but\n\
5317	false for naked functions. The default implementation always returns true.",
5318	bool, (void),
5319	hook_bool_void_true)
5320
5321	/* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
5322	is true, then it should be for the callee; otherwise for the caller. */
5323	DEFHOOK
5324	(static_chain,
5325	"This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
5326	targets that may use different static chain locations for different\n\
5327	nested functions. This may be required if the target has function\n\
5328	attributes that affect the calling conventions of the function and\n\
5329	those calling conventions use different static chain locations.\n\
5330	\n\
5331	The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
5332	\n\
5333	If the static chain is passed in memory, this hook should be used to\n\
5334	provide rtx giving @code{mem} expressions that denote where they are stored.\n\
5335	Often the @code{mem} expression as seen by the caller will be at an offset\n\
5336	from the stack pointer and the @code{mem} expression as seen by the callee\n\
5337	will be at an offset from the frame pointer.\n\
5338	@findex stack_pointer_rtx\n\
5339	@findex frame_pointer_rtx\n\
5340	@findex arg_pointer_rtx\n\
5341	The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
5342	@code{arg_pointer_rtx} will have been initialized and should be used\n\
5343	to refer to those items.",
5344	rtx, (const_tree fndecl_or_type, bool incoming_p),
5345	default_static_chain)
5346
5347	/* Fill in the trampoline at MEM with a call to FNDECL and a
5348	static chain value of CHAIN. */
5349	DEFHOOK
5350	(trampoline_init,
5351	"This hook is called to initialize a trampoline.\n\
5352	@var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
5353	is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
5354	RTX for the static chain value that should be passed to the function\n\
5355	when it is called.\n\
5356	\n\
5357	If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
5358	first thing this hook should do is emit a block move into @var{m_tramp}\n\
5359	from the memory block returned by @code{assemble_trampoline_template}.\n\
5360	Note that the block move need only cover the constant parts of the\n\
5361	trampoline. If the target isolates the variable parts of the trampoline\n\
5362	to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
5363	\n\
5364	If the target requires any other actions, such as flushing caches\n\
5365	(possibly calling function maybe_emit_call_builtin___clear_cache) or\n\
5366	enabling stack execution, these actions should be performed after\n\
5367	initializing the trampoline proper.",
5368	void, (rtx m_tramp, tree fndecl, rtx static_chain),
5369	default_trampoline_init)
5370
5371	/* Emit a call to a function to clear the instruction cache. */
5372	DEFHOOK
5373	(emit_call_builtin___clear_cache,
5374	"On targets that do not define a @code{clear_cache} insn expander,\n\
5375	but that define the @code{CLEAR_CACHE_INSN} macro,\n\
5376	maybe_emit_call_builtin___clear_cache relies on this target hook\n\
5377	to clear an address range in the instruction cache.\n\
5378	\n\
5379	The default implementation calls the @code{__clear_cache} builtin,\n\
5380	taking the assembler name from the builtin declaration. Overriding\n\
5381	definitions may call alternate functions, with alternate calling\n\
5382	conventions, or emit alternate RTX to perform the job.",
5383	void, (rtx begin, rtx end),
5384	default_emit_call_builtin___clear_cache)
5385
5386	/* Adjust the address of the trampoline in a target-specific way. */
5387	DEFHOOK
5388	(trampoline_adjust_address,
5389	"This hook should perform any machine-specific adjustment in\n\
5390	the address of the trampoline. Its argument contains the address of the\n\
5391	memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
5392	the address to be used for a function call should be different from the\n\
5393	address at which the template was stored, the different address should\n\
5394	be returned; otherwise @var{addr} should be returned unchanged.\n\
5395	If this hook is not defined, @var{addr} will be used for function calls.",
5396	rtx, (rtx addr), NULL)
5397
5398	DEFHOOKPOD
5399	(custom_function_descriptors,
5400	"If the target can use GCC's generic descriptor mechanism for nested\n\
5401	functions, define this hook to a power of 2 representing an unused bit\n\
5402	in function pointers which can be used to differentiate descriptors at\n\
5403	run time. This value gives the number of bytes by which descriptor\n\
5404	pointers are misaligned compared to function pointers. For example, on\n\
5405	targets that require functions to be aligned to a 4-byte boundary, a\n\
5406	value of either 1 or 2 is appropriate unless the architecture already\n\
5407	reserves the bit for another purpose, such as on ARM.\n\
5408	\n\
5409	Define this hook to 0 if the target implements ABI support for\n\
5410	function descriptors in its standard calling sequence, like for example\n\
5411	HPPA or IA-64.\n\
5412	\n\
5413	Using descriptors for nested functions\n\
5414	eliminates the need for trampolines that reside on the stack and require\n\
5415	it to be made executable.",
5416	int, -1)
5417
5418	/* Return the number of bytes of its own arguments that a function
5419	pops on returning, or 0 if the function pops no arguments and the
5420	caller must therefore pop them all after the function returns. */
5421	/* ??? tm.texi has no types for the parameters. */
5422	DEFHOOK
5423	(return_pops_args,
5424	"This target hook returns the number of bytes of its own arguments that\n\
5425	a function pops on returning, or 0 if the function pops no arguments\n\
5426	and the caller must therefore pop them all after the function returns.\n\
5427	\n\
5428	@var{fundecl} is a C variable whose value is a tree node that describes\n\
5429	the function in question. Normally it is a node of type\n\
5430	@code{FUNCTION_DECL} that describes the declaration of the function.\n\
5431	From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
5432	\n\
5433	@var{funtype} is a C variable whose value is a tree node that\n\
5434	describes the function in question. Normally it is a node of type\n\
5435	@code{FUNCTION_TYPE} that describes the data type of the function.\n\
5436	From this it is possible to obtain the data types of the value and\n\
5437	arguments (if known).\n\
5438	\n\
5439	When a call to a library function is being considered, @var{fundecl}\n\
5440	will contain an identifier node for the library function. Thus, if\n\
5441	you need to distinguish among various library functions, you can do so\n\
5442	by their names. Note that ``library function'' in this context means\n\
5443	a function used to perform arithmetic, whose name is known specially\n\
5444	in the compiler and was not mentioned in the C code being compiled.\n\
5445	\n\
5446	@var{size} is the number of bytes of arguments passed on the\n\
5447	stack. If a variable number of bytes is passed, it is zero, and\n\
5448	argument popping will always be the responsibility of the calling function.\n\
5449	\n\
5450	On the VAX, all functions always pop their arguments, so the definition\n\
5451	of this macro is @var{size}. On the 68000, using the standard\n\
5452	calling convention, no functions pop their arguments, so the value of\n\
5453	the macro is always 0 in this case. But an alternative calling\n\
5454	convention is available in which functions that take a fixed number of\n\
5455	arguments pop them but other functions (such as @code{printf}) pop\n\
5456	nothing (the caller pops all). When this convention is in use,\n\
5457	@var{funtype} is examined to determine whether a function takes a fixed\n\
5458	number of arguments.",
5459	poly_int64, (tree fundecl, tree funtype, poly_int64 size),
5460	default_return_pops_args)
5461
5462	/* Return a mode wide enough to copy any function value that might be
5463	returned. */
5464	DEFHOOK
5465	(get_raw_result_mode,
5466	"This target hook returns the mode to be used when accessing raw return\n\
5467	registers in @code{__builtin_return}. Define this macro if the value\n\
5468	in @var{reg_raw_mode} is not correct. Use @code{VOIDmode} if a register\n\
5469	should be ignored for @code{__builtin_return} purposes.",
5470	fixed_size_mode, (int regno),
5471	default_get_reg_raw_mode)
5472
5473	/* Return a mode wide enough to copy any argument value that might be
5474	passed. */
5475	DEFHOOK
5476	(get_raw_arg_mode,
5477	"This target hook returns the mode to be used when accessing raw argument\n\
5478	registers in @code{__builtin_apply_args}. Define this macro if the value\n\
5479	in @var{reg_raw_mode} is not correct. Use @code{VOIDmode} if a register\n\
5480	should be ignored for @code{__builtin_apply_args} purposes.",
5481	fixed_size_mode, (int regno),
5482	default_get_reg_raw_mode)
5483
5484	/* Return true if a type is an empty record. */
5485	DEFHOOK
5486	(empty_record_p,
5487	"This target hook returns true if the type is an empty record. The default\n\
5488	is to return @code{false}.",
5489	bool, (const_tree type),
5490	hook_bool_const_tree_false)
5491
5492	/* Warn about the change in empty class parameter passing ABI. */
5493	DEFHOOK
5494	(warn_parameter_passing_abi,
5495	"This target hook warns about the change in empty class parameter passing\n\
5496	ABI.",
5497	void, (cumulative_args_t ca, tree type),
5498	hook_void_CUMULATIVE_ARGS_tree)
5499
5500	HOOK_VECTOR_END (calls)
5501
5502	DEFHOOK
5503	(use_pseudo_pic_reg,
5504	"This hook should return 1 in case pseudo register should be created\n\
5505	for pic_offset_table_rtx during function expand.",
5506	bool, (void),
5507	hook_bool_void_false)
5508
5509	DEFHOOK
5510	(init_pic_reg,
5511	"Perform a target dependent initialization of pic_offset_table_rtx.\n\
5512	This hook is called at the start of register allocation.",
5513	void, (void),
5514	hook_void_void)
5515
5516	/* Return the diagnostic message string if conversion from FROMTYPE
5517	to TOTYPE is not allowed, NULL otherwise. */
5518	DEFHOOK
5519	(invalid_conversion,
5520	"If defined, this macro returns the diagnostic message when it is\n\
5521	invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
5522	if validity should be determined by the front end.",
5523	const char *, (const_tree fromtype, const_tree totype),
5524	hook_constcharptr_const_tree_const_tree_null)
5525
5526	/* Return the diagnostic message string if the unary operation OP is
5527	not permitted on TYPE, NULL otherwise. */
5528	DEFHOOK
5529	(invalid_unary_op,
5530	"If defined, this macro returns the diagnostic message when it is\n\
5531	invalid to apply operation @var{op} (where unary plus is denoted by\n\
5532	@code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
5533	if validity should be determined by the front end.",
5534	const char *, (int op, const_tree type),
5535	hook_constcharptr_int_const_tree_null)
5536
5537	/* Return the diagnostic message string if the binary operation OP
5538	is not permitted on TYPE1 and TYPE2, NULL otherwise. */
5539	DEFHOOK
5540	(invalid_binary_op,
5541	"If defined, this macro returns the diagnostic message when it is\n\
5542	invalid to apply operation @var{op} to operands of types @var{type1}\n\
5543	and @var{type2}, or @code{NULL} if validity should be determined by\n\
5544	the front end.",
5545	const char *, (int op, const_tree type1, const_tree type2),
5546	hook_constcharptr_int_const_tree_const_tree_null)
5547
5548	/* If values of TYPE are promoted to some other type when used in
5549	expressions (analogous to the integer promotions), return that type,
5550	or NULL_TREE otherwise. */
5551	DEFHOOK
5552	(promoted_type,
5553	"If defined, this target hook returns the type to which values of\n\
5554	@var{type} should be promoted when they appear in expressions,\n\
5555	analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
5556	front end's normal promotion rules. This hook is useful when there are\n\
5557	target-specific types with special promotion rules.\n\
5558	This is currently used only by the C and C++ front ends.",
5559	tree, (const_tree type),
5560	hook_tree_const_tree_null)
5561
5562	/* Convert EXPR to TYPE, if target-specific types with special conversion
5563	rules are involved. Return the converted expression, or NULL to apply
5564	the standard conversion rules. */
5565	DEFHOOK
5566	(convert_to_type,
5567	"If defined, this hook returns the result of converting @var{expr} to\n\
5568	@var{type}. It should return the converted expression,\n\
5569	or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
5570	This hook is useful when there are target-specific types with special\n\
5571	conversion rules.\n\
5572	This is currently used only by the C and C++ front ends.",
5573	tree, (tree type, tree expr),
5574	hook_tree_tree_tree_null)
5575
5576	DEFHOOK
5577	(verify_type_context,
5578	"If defined, this hook returns false if there is a target-specific reason\n\
5579	why type @var{type} cannot be used in the source language context described\n\
5580	by @var{context}. When @var{silent_p} is false, the hook also reports an\n\
5581	error against @var{loc} for invalid uses of @var{type}.\n\
5582	\n\
5583	Calls to this hook should be made through the global function\n\
5584	@code{verify_type_context}, which makes the @var{silent_p} parameter\n\
5585	default to false and also handles @code{error_mark_node}.\n\
5586	\n\
5587	The default implementation always returns true.",
5588	bool, (location_t loc, type_context_kind context, const_tree type,
5589	bool silent_p),
5590	NULL)
5591
5592	DEFHOOK
5593	(can_change_mode_class,
5594	"This hook returns true if it is possible to bitcast values held in\n\
5595	registers of class @var{rclass} from mode @var{from} to mode @var{to}\n\
5596	and if doing so preserves the low-order bits that are common to both modes.\n\
5597	The result is only meaningful if @var{rclass} has registers that can hold\n\
5598	both @code{from} and @code{to}. The default implementation returns true.\n\
5599	\n\
5600	As an example of when such bitcasting is invalid, loading 32-bit integer or\n\
5601	floating-point objects into floating-point registers on Alpha extends them\n\
5602	to 64 bits. Therefore loading a 64-bit object and then storing it as a\n\
5603	32-bit object does not store the low-order 32 bits, as would be the case\n\
5604	for a normal register. Therefore, @file{alpha.h} defines\n\
5605	@code{TARGET_CAN_CHANGE_MODE_CLASS} to return:\n\
5606	\n\
5607	@smallexample\n\
5608	(GET_MODE_SIZE (from) == GET_MODE_SIZE (to)\n\
5609	|| !reg_classes_intersect_p (FLOAT_REGS, rclass))\n\
5610	@end smallexample\n\
5611	\n\
5612	Even if storing from a register in mode @var{to} would be valid,\n\
5613	if both @var{from} and @code{raw_reg_mode} for @var{rclass} are wider\n\
5614	than @code{word_mode}, then we must prevent @var{to} narrowing the\n\
5615	mode. This happens when the middle-end assumes that it can load\n\
5616	or store pieces of an @var{N}-word pseudo, and that the pseudo will\n\
5617	eventually be allocated to @var{N} @code{word_mode} hard registers.\n\
5618	Failure to prevent this kind of mode change will result in the\n\
5619	entire @code{raw_reg_mode} being modified instead of the partial\n\
5620	value that the middle-end intended.",
5621	bool, (machine_mode from, machine_mode to, reg_class_t rclass),
5622	hook_bool_mode_mode_reg_class_t_true)
5623
5624	/* Change pseudo allocno class calculated by IRA. */
5625	DEFHOOK
5626	(ira_change_pseudo_allocno_class,
5627	"A target hook which can change allocno class for given pseudo from\n\
5628	allocno and best class calculated by IRA.\n\
5629	\n\
5630	The default version of this target hook always returns given class.",
5631	reg_class_t, (int, reg_class_t, reg_class_t),
5632	default_ira_change_pseudo_allocno_class)
5633
5634	/* Return true if we use LRA instead of reload. */
5635	DEFHOOK
5636	(lra_p,
5637	"A target hook which returns true if we use LRA instead of reload pass.\n\
5638	\n\
5639	The default version of this target hook returns true. New ports\n\
5640	should use LRA, and existing ports are encouraged to convert.",
5641	bool, (void),
5642	default_lra_p)
5643
5644	/* Return register priority of given hard regno for the current target. */
5645	DEFHOOK
5646	(register_priority,
5647	"A target hook which returns the register priority number to which the\n\
5648	register @var{hard_regno} belongs to. The bigger the number, the\n\
5649	more preferable the hard register usage (when all other conditions are\n\
5650	the same). This hook can be used to prefer some hard register over\n\
5651	others in LRA. For example, some x86-64 register usage needs\n\
5652	additional prefix which makes instructions longer. The hook can\n\
5653	return lower priority number for such registers make them less favorable\n\
5654	and as result making the generated code smaller.\n\
5655	\n\
5656	The default version of this target hook returns always zero.",
5657	int, (int),
5658	default_register_priority)
5659
5660	/* Return true if we need register usage leveling. */
5661	DEFHOOK
5662	(register_usage_leveling_p,
5663	"A target hook which returns true if we need register usage leveling.\n\
5664	That means if a few hard registers are equally good for the\n\
5665	assignment, we choose the least used hard register. The register\n\
5666	usage leveling may be profitable for some targets. Don't use the\n\
5667	usage leveling for targets with conditional execution or targets\n\
5668	with big register files as it hurts if-conversion and cross-jumping\n\
5669	optimizations.\n\
5670	\n\
5671	The default version of this target hook returns always false.",
5672	bool, (void),
5673	default_register_usage_leveling_p)
5674
5675	/* Return true if maximal address displacement can be different. */
5676	DEFHOOK
5677	(different_addr_displacement_p,
5678	"A target hook which returns true if an address with the same structure\n\
5679	can have different maximal legitimate displacement. For example, the\n\
5680	displacement can depend on memory mode or on operand combinations in\n\
5681	the insn.\n\
5682	\n\
5683	The default version of this target hook returns always false.",
5684	bool, (void),
5685	default_different_addr_displacement_p)
5686
5687	/* Determine class for spilling pseudos of given mode into registers
5688	instead of memory. */
5689	DEFHOOK
5690	(spill_class,
5691	"This hook defines a class of registers which could be used for spilling\n\
5692	pseudos of the given mode and class, or @code{NO_REGS} if only memory\n\
5693	should be used. Not defining this hook is equivalent to returning\n\
5694	@code{NO_REGS} for all inputs.",
5695	reg_class_t, (reg_class_t, machine_mode),
5696	NULL)
5697
5698	/* Determine an additional allocno class. */
5699	DEFHOOK
5700	(additional_allocno_class_p,
5701	"This hook should return @code{true} if given class of registers should\n\
5702	be an allocno class in any way. Usually RA uses only one register\n\
5703	class from all classes containing the same register set. In some\n\
5704	complicated cases, you need to have two or more such classes as\n\
5705	allocno ones for RA correct work. Not defining this hook is\n\
5706	equivalent to returning @code{false} for all inputs.",
5707	bool, (reg_class_t),
5708	hook_bool_reg_class_t_false)
5709
5710	DEFHOOK
5711	(cstore_mode,
5712	"This hook defines the machine mode to use for the boolean result of\n\
5713	conditional store patterns. The ICODE argument is the instruction code\n\
5714	for the cstore being performed. Not definiting this hook is the same\n\
5715	as accepting the mode encoded into operand 0 of the cstore expander\n\
5716	patterns.",
5717	scalar_int_mode, (enum insn_code icode),
5718	default_cstore_mode)
5719
5720	/* This target hook allows the backend to compute the register pressure
5721	classes to use. */
5722	DEFHOOK
5723	(compute_pressure_classes,
5724	"A target hook which lets a backend compute the set of pressure classes to\n\
5725	be used by those optimization passes which take register pressure into\n\
5726	account, as opposed to letting IRA compute them. It returns the number of\n\
5727	register classes stored in the array @var{pressure_classes}.",
5728	int, (enum reg_class *pressure_classes), NULL)
5729
5730	/* True if a structure, union or array with MODE containing FIELD should
5731	be accessed using BLKmode. */
5732	DEFHOOK
5733	(member_type_forces_blk,
5734	"Return true if a structure, union or array containing @var{field} should\n\
5735	be accessed using @code{BLKMODE}.\n\
5736	\n\
5737	If @var{field} is the only field in the structure, @var{mode} is its\n\
5738	mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
5739	case where structures of one field would require the structure's mode to\n\
5740	retain the field's mode.\n\
5741	\n\
5742	Normally, this is not needed.",
5743	bool, (const_tree field, machine_mode mode),
5744	default_member_type_forces_blk)
5745
5746	/* See tree-ssa-math-opts.cc:divmod_candidate_p for conditions
5747	that gate the divod transform. */
5748	DEFHOOK
5749	(expand_divmod_libfunc,
5750	"Define this hook for enabling divmod transform if the port does not have\n\
5751	hardware divmod insn but defines target-specific divmod libfuncs.",
5752	void, (rtx libfunc, machine_mode mode, rtx op0, rtx op1, rtx *quot, rtx *rem),
5753	NULL)
5754
5755	/* Return the class for a secondary reload, and fill in extra information. */
5756	DEFHOOK
5757	(secondary_reload,
5758	"Many machines have some registers that cannot be copied directly to or\n\
5759	from memory or even from other types of registers. An example is the\n\
5760	@samp{MQ} register, which on most machines, can only be copied to or\n\
5761	from general registers, but not memory. Below, we shall be using the\n\
5762	term 'intermediate register' when a move operation cannot be performed\n\
5763	directly, but has to be done by copying the source into the intermediate\n\
5764	register first, and then copying the intermediate register to the\n\
5765	destination. An intermediate register always has the same mode as\n\
5766	source and destination. Since it holds the actual value being copied,\n\
5767	reload might apply optimizations to re-use an intermediate register\n\
5768	and eliding the copy from the source when it can determine that the\n\
5769	intermediate register still holds the required value.\n\
5770	\n\
5771	Another kind of secondary reload is required on some machines which\n\
5772	allow copying all registers to and from memory, but require a scratch\n\
5773	register for stores to some memory locations (e.g., those with symbolic\n\
5774	address on the RT, and those with certain symbolic address on the SPARC\n\
5775	when compiling PIC)@. Scratch registers need not have the same mode\n\
5776	as the value being copied, and usually hold a different value than\n\
5777	that being copied. Special patterns in the md file are needed to\n\
5778	describe how the copy is performed with the help of the scratch register;\n\
5779	these patterns also describe the number, register class(es) and mode(s)\n\
5780	of the scratch register(s).\n\
5781	\n\
5782	In some cases, both an intermediate and a scratch register are required.\n\
5783	\n\
5784	For input reloads, this target hook is called with nonzero @var{in_p},\n\
5785	and @var{x} is an rtx that needs to be copied to a register of class\n\
5786	@var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
5787	hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
5788	needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
5789	\n\
5790	If copying a register of @var{reload_class} from/to @var{x} requires\n\
5791	an intermediate register, the hook @code{secondary_reload} should\n\
5792	return the register class required for this intermediate register.\n\
5793	If no intermediate register is required, it should return NO_REGS.\n\
5794	If more than one intermediate register is required, describe the one\n\
5795	that is closest in the copy chain to the reload register.\n\
5796	\n\
5797	If scratch registers are needed, you also have to describe how to\n\
5798	perform the copy from/to the reload register to/from this\n\
5799	closest intermediate register. Or if no intermediate register is\n\
5800	required, but still a scratch register is needed, describe the\n\
5801	copy from/to the reload register to/from the reload operand @var{x}.\n\
5802	\n\
5803	You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
5804	in the md file which performs the move. Operands 0 and 1 are the output\n\
5805	and input of this copy, respectively. Operands from operand 2 onward are\n\
5806	for scratch operands. These scratch operands must have a mode, and a\n\
5807	single-register-class\n\
5808	@c [later: or memory]\n\
5809	output constraint.\n\
5810	\n\
5811	When an intermediate register is used, the @code{secondary_reload}\n\
5812	hook will be called again to determine how to copy the intermediate\n\
5813	register to/from the reload operand @var{x}, so your hook must also\n\
5814	have code to handle the register class of the intermediate operand.\n\
5815	\n\
5816	@c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5817	@c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5818	@c and match the constraints of input and output to determine the required\n\
5819	@c alternative. A restriction would be that constraints used to match\n\
5820	@c against reloads registers would have to be written as register class\n\
5821	@c constraints, or we need a new target macro / hook that tells us if an\n\
5822	@c arbitrary constraint can match an unknown register of a given class.\n\
5823	@c Such a macro / hook would also be useful in other places.]\n\
5824	\n\
5825	\n\
5826	@var{x} might be a pseudo-register or a @code{subreg} of a\n\
5827	pseudo-register, which could either be in a hard register or in memory.\n\
5828	Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5829	in memory and the hard register number if it is in a register.\n\
5830	\n\
5831	Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5832	currently not supported. For the time being, you will have to continue\n\
5833	to use @code{TARGET_SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5834	\n\
5835	@code{copy_cost} also uses this target hook to find out how values are\n\
5836	copied. If you want it to include some extra cost for the need to allocate\n\
5837	(a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5838	Or if two dependent moves are supposed to have a lower cost than the sum\n\
5839	of the individual moves due to expected fortuitous scheduling and/or special\n\
5840	forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5841	reg_class_t,
5842	(bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5843	secondary_reload_info *sri),
5844	default_secondary_reload)
5845
5846	DEFHOOK
5847	(secondary_memory_needed,
5848	"Certain machines have the property that some registers cannot be copied\n\
5849	to some other registers without using memory. Define this hook on\n\
5850	those machines to return true if objects of mode @var{m} in registers\n\
5851	of @var{class1} can only be copied to registers of class @var{class2} by\n\
5852	storing a register of @var{class1} into memory and loading that memory\n\
5853	location into a register of @var{class2}. The default definition returns\n\
5854	false for all inputs.",
5855	bool, (machine_mode mode, reg_class_t class1, reg_class_t class2),
5856	hook_bool_mode_reg_class_t_reg_class_t_false)
5857
5858	DEFHOOK
5859	(secondary_memory_needed_mode,
5860	"If @code{TARGET_SECONDARY_MEMORY_NEEDED} tells the compiler to use memory\n\
5861	when moving between two particular registers of mode @var{mode},\n\
5862	this hook specifies the mode that the memory should have.\n\
5863	\n\
5864	The default depends on @code{TARGET_LRA_P}. Without LRA, the default\n\
5865	is to use a word-sized mode for integral modes that are smaller than a\n\
5866	a word. This is right thing to do on most machines because it ensures\n\
5867	that all bits of the register are copied and prevents accesses to the\n\
5868	registers in a narrower mode, which some machines prohibit for\n\
5869	floating-point registers.\n\
5870	\n\
5871	However, this default behavior is not correct on some machines, such as\n\
5872	the DEC Alpha, that store short integers in floating-point registers\n\
5873	differently than in integer registers. On those machines, the default\n\
5874	widening will not work correctly and you must define this hook to\n\
5875	suppress that widening in some cases. See the file @file{alpha.cc} for\n\
5876	details.\n\
5877	\n\
5878	With LRA, the default is to use @var{mode} unmodified.",
5879	machine_mode, (machine_mode mode),
5880	default_secondary_memory_needed_mode)
5881
5882	/* Given an rtx X being reloaded into a reg required to be in class CLASS,
5883	return the class of reg to actually use. */
5884	DEFHOOK
5885	(preferred_reload_class,
5886	"A target hook that places additional restrictions on the register class\n\
5887	to use when it is necessary to copy value @var{x} into a register in class\n\
5888	@var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5889	another, smaller class.\n\
5890	\n\
5891	The default version of this hook always returns value of @code{rclass} argument.\n\
5892	\n\
5893	Sometimes returning a more restrictive class makes better code. For\n\
5894	example, on the 68000, when @var{x} is an integer constant that is in range\n\
5895	for a @samp{moveq} instruction, the value of this macro is always\n\
5896	@code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5897	Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5898	\n\
5899	One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5900	@var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5901	loaded into some register class. By returning @code{NO_REGS} you can\n\
5902	force @var{x} into a memory location. For example, rs6000 can load\n\
5903	immediate values into general-purpose registers, but does not have an\n\
5904	instruction for loading an immediate value into a floating-point\n\
5905	register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5906	@var{x} is a floating-point constant. If the constant can't be loaded\n\
5907	into any kind of register, code generation will be better if\n\
5908	@code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5909	of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5910	\n\
5911	If an insn has pseudos in it after register allocation, reload will go\n\
5912	through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5913	to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5914	reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5915	this feature to discourage usage of 387 registers when math is done in\n\
5916	the SSE registers (and vice versa).",
5917	reg_class_t,
5918	(rtx x, reg_class_t rclass),
5919	default_preferred_reload_class)
5920
5921	/* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5922	input reloads. */
5923	DEFHOOK
5924	(preferred_output_reload_class,
5925	"Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5926	input reloads.\n\
5927	\n\
5928	The default version of this hook always returns value of @code{rclass}\n\
5929	argument.\n\
5930	\n\
5931	You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5932	reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5933	reg_class_t,
5934	(rtx x, reg_class_t rclass),
5935	default_preferred_output_reload_class)
5936
5937	DEFHOOK
5938	(select_early_remat_modes,
5939	"On some targets, certain modes cannot be held in registers around a\n\
5940	standard ABI call and are relatively expensive to spill to the stack.\n\
5941	The early rematerialization pass can help in such cases by aggressively\n\
5942	recomputing values after calls, so that they don't need to be spilled.\n\
5943	\n\
5944	This hook returns the set of such modes by setting the associated bits\n\
5945	in @var{modes}. The default implementation selects no modes, which has\n\
5946	the effect of disabling the early rematerialization pass.",
5947	void, (sbitmap modes),
5948	default_select_early_remat_modes)
5949
5950	DEFHOOK
5951	(class_likely_spilled_p,
5952	"A target hook which returns @code{true} if pseudos that have been assigned\n\
5953	to registers of class @var{rclass} would likely be spilled because\n\
5954	registers of @var{rclass} are needed for spill registers.\n\
5955	\n\
5956	The default version of this target hook returns @code{true} if @var{rclass}\n\
5957	has exactly one register and @code{false} otherwise. On most machines, this\n\
5958	default should be used. For generally register-starved machines, such as\n\
5959	i386, or machines with right register constraints, such as SH, this hook\n\
5960	can be used to avoid excessive spilling.\n\
5961	\n\
5962	This hook is also used by some of the global intra-procedural code\n\
5963	transformations to throtle code motion, to avoid increasing register\n\
5964	pressure.",
5965	bool, (reg_class_t rclass),
5966	default_class_likely_spilled_p)
5967
5968	/* Return the maximum number of consecutive registers
5969	needed to represent mode MODE in a register of class RCLASS. */
5970	DEFHOOK
5971	(class_max_nregs,
5972	"A target hook returns the maximum number of consecutive registers\n\
5973	of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5974	\n\
5975	This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}.\n\
5976	In fact, the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5977	@var{mode})} target hook should be the maximum value of\n\
5978	@code{TARGET_HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5979	values in the class @var{rclass}.\n\
5980	\n\
5981	This target hook helps control the handling of multiple-word values\n\
5982	in the reload pass.\n\
5983	\n\
5984	The default version of this target hook returns the size of @var{mode}\n\
5985	in words.",
5986	unsigned char, (reg_class_t rclass, machine_mode mode),
5987	default_class_max_nregs)
5988
5989	DEFHOOK
5990	(preferred_rename_class,
5991	"A target hook that places additional preference on the register\n\
5992	class to use when it is necessary to rename a register in class\n\
5993	@var{rclass} to another class, or perhaps @var{NO_REGS}, if no\n\
5994	preferred register class is found or hook @code{preferred_rename_class}\n\
5995	is not implemented.\n\
5996	Sometimes returning a more restrictive class makes better code. For\n\
5997	example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\n\
5998	smaller than instructions using @code{GENERIC_REGS}. By returning\n\
5999	@code{LO_REGS} from @code{preferred_rename_class}, code size can\n\
6000	be reduced.",
6001	reg_class_t, (reg_class_t rclass),
6002	default_preferred_rename_class)
6003
6004	/* This target hook allows the backend to avoid unsafe substitution
6005	during register allocation. */
6006	DEFHOOK
6007	(cannot_substitute_mem_equiv_p,
6008	"A target hook which returns @code{true} if @var{subst} can't\n\
6009	substitute safely pseudos with equivalent memory values during\n\
6010	register allocation.\n\
6011	The default version of this target hook returns @code{false}.\n\
6012	On most machines, this default should be used. For generally\n\
6013	machines with non orthogonal register usage for addressing, such\n\
6014	as SH, this hook can be used to avoid excessive spilling.",
6015	bool, (rtx subst),
6016	hook_bool_rtx_false)
6017
6018	/* This target hook allows the backend to legitimize base plus
6019	displacement addressing. */
6020	DEFHOOK
6021	(legitimize_address_displacement,
6022	"This hook tries to split address offset @var{orig_offset} into\n\
6023	two parts: one that should be added to the base address to create\n\
6024	a local anchor point, and an additional offset that can be applied\n\
6025	to the anchor to address a value of mode @var{mode}. The idea is that\n\
6026	the local anchor could be shared by other accesses to nearby locations.\n\
6027	\n\
6028	The hook returns true if it succeeds, storing the offset of the\n\
6029	anchor from the base in @var{offset1} and the offset of the final address\n\
6030	from the anchor in @var{offset2}. The default implementation returns false.",
6031	bool, (rtx *offset1, rtx *offset2, poly_int64 orig_offset, machine_mode mode),
6032	default_legitimize_address_displacement)
6033
6034	/* This target hook allows the backend to perform additional
6035	processing while initializing for variable expansion. */
6036	DEFHOOK
6037	(expand_to_rtl_hook,
6038	"This hook is called just before expansion into rtl, allowing the target\n\
6039	to perform additional initializations or analysis before the expansion.\n\
6040	For example, the rs6000 port uses it to allocate a scratch stack slot\n\
6041	for use in copying SDmode values between memory and floating point\n\
6042	registers whenever the function being expanded has any SDmode\n\
6043	usage.",
6044	void, (void),
6045	hook_void_void)
6046
6047	/* This target hook allows the backend to perform additional
6048	instantiations on rtx that are not actually in insns yet,
6049	but will be later. */
6050	DEFHOOK
6051	(instantiate_decls,
6052	"This hook allows the backend to perform additional instantiations on rtl\n\
6053	that are not actually in any insns yet, but will be later.",
6054	void, (void),
6055	hook_void_void)
6056
6057	DEFHOOK
6058	(hard_regno_nregs,
6059	"This hook returns the number of consecutive hard registers, starting\n\
6060	at register number @var{regno}, required to hold a value of mode\n\
6061	@var{mode}. This hook must never return zero, even if a register\n\
6062	cannot hold the requested mode - indicate that with\n\
6063	@code{TARGET_HARD_REGNO_MODE_OK} and/or\n\
6064	@code{TARGET_CAN_CHANGE_MODE_CLASS} instead.\n\
6065	\n\
6066	The default definition returns the number of words in @var{mode}.",
6067	unsigned int, (unsigned int regno, machine_mode mode),
6068	default_hard_regno_nregs)
6069
6070	DEFHOOK
6071	(hard_regno_mode_ok,
6072	"This hook returns true if it is permissible to store a value\n\
6073	of mode @var{mode} in hard register number @var{regno} (or in several\n\
6074	registers starting with that one). The default definition returns true\n\
6075	unconditionally.\n\
6076	\n\
6077	You need not include code to check for the numbers of fixed registers,\n\
6078	because the allocation mechanism considers them to be always occupied.\n\
6079	\n\
6080	@cindex register pairs\n\
6081	On some machines, double-precision values must be kept in even/odd\n\
6082	register pairs. You can implement that by defining this hook to reject\n\
6083	odd register numbers for such modes.\n\
6084	\n\
6085	The minimum requirement for a mode to be OK in a register is that the\n\
6086	@samp{mov@var{mode}} instruction pattern support moves between the\n\
6087	register and other hard register in the same class and that moving a\n\
6088	value into the register and back out not alter it.\n\
6089	\n\
6090	Since the same instruction used to move @code{word_mode} will work for\n\
6091	all narrower integer modes, it is not necessary on any machine for\n\
6092	this hook to distinguish between these modes, provided you define\n\
6093	patterns @samp{movhi}, etc., to take advantage of this. This is\n\
6094	useful because of the interaction between @code{TARGET_HARD_REGNO_MODE_OK}\n\
6095	and @code{TARGET_MODES_TIEABLE_P}; it is very desirable for all integer\n\
6096	modes to be tieable.\n\
6097	\n\
6098	Many machines have special registers for floating point arithmetic.\n\
6099	Often people assume that floating point machine modes are allowed only\n\
6100	in floating point registers. This is not true. Any registers that\n\
6101	can hold integers can safely @emph{hold} a floating point machine\n\
6102	mode, whether or not floating arithmetic can be done on it in those\n\
6103	registers. Integer move instructions can be used to move the values.\n\
6104	\n\
6105	On some machines, though, the converse is true: fixed-point machine\n\
6106	modes may not go in floating registers. This is true if the floating\n\
6107	registers normalize any value stored in them, because storing a\n\
6108	non-floating value there would garble it. In this case,\n\
6109	@code{TARGET_HARD_REGNO_MODE_OK} should reject fixed-point machine modes in\n\
6110	floating registers. But if the floating registers do not automatically\n\
6111	normalize, if you can store any bit pattern in one and retrieve it\n\
6112	unchanged without a trap, then any machine mode may go in a floating\n\
6113	register, so you can define this hook to say so.\n\
6114	\n\
6115	The primary significance of special floating registers is rather that\n\
6116	they are the registers acceptable in floating point arithmetic\n\
6117	instructions. However, this is of no concern to\n\
6118	@code{TARGET_HARD_REGNO_MODE_OK}. You handle it by writing the proper\n\
6119	constraints for those instructions.\n\
6120	\n\
6121	On some machines, the floating registers are especially slow to access,\n\
6122	so that it is better to store a value in a stack frame than in such a\n\
6123	register if floating point arithmetic is not being done. As long as the\n\
6124	floating registers are not in class @code{GENERAL_REGS}, they will not\n\
6125	be used unless some pattern's constraint asks for one.",
6126	bool, (unsigned int regno, machine_mode mode),
6127	hook_bool_uint_mode_true)
6128
6129	DEFHOOK
6130	(modes_tieable_p,
6131	"This hook returns true if a value of mode @var{mode1} is accessible\n\
6132	in mode @var{mode2} without copying.\n\
6133	\n\
6134	If @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and\n\
6135	@code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always\n\
6136	the same for any @var{r}, then\n\
6137	@code{TARGET_MODES_TIEABLE_P (@var{mode1}, @var{mode2})}\n\
6138	should be true. If they differ for any @var{r}, you should define\n\
6139	this hook to return false unless some other mechanism ensures the\n\
6140	accessibility of the value in a narrower mode.\n\
6141	\n\
6142	You should define this hook to return true in as many cases as\n\
6143	possible since doing so will allow GCC to perform better register\n\
6144	allocation. The default definition returns true unconditionally.",
6145	bool, (machine_mode mode1, machine_mode mode2),
6146	hook_bool_mode_mode_true)
6147
6148	/* Return true if is OK to use a hard register REGNO as scratch register
6149	in peephole2. */
6150	DEFHOOK
6151	(hard_regno_scratch_ok,
6152	"This target hook should return @code{true} if it is OK to use a hard register\n\
6153	@var{regno} as scratch reg in peephole2.\n\
6154	\n\
6155	One common use of this macro is to prevent using of a register that\n\
6156	is not saved by a prologue in an interrupt handler.\n\
6157	\n\
6158	The default version of this hook always returns @code{true}.",
6159	bool, (unsigned int regno),
6160	default_hard_regno_scratch_ok)
6161
6162	DEFHOOK
6163	(hard_regno_call_part_clobbered,
6164	"ABIs usually specify that calls must preserve the full contents\n\
6165	of a particular register, or that calls can alter any part of a\n\
6166	particular register. This information is captured by the target macro\n\
6167	@code{CALL_REALLY_USED_REGISTERS}. However, some ABIs specify that calls\n\
6168	must preserve certain bits of a particular register but can alter others.\n\
6169	This hook should return true if this applies to at least one of the\n\
6170	registers in @samp{(reg:@var{mode} @var{regno})}, and if as a result the\n\
6171	call would alter part of the @var{mode} value. For example, if a call\n\
6172	preserves the low 32 bits of a 64-bit hard register @var{regno} but can\n\
6173	clobber the upper 32 bits, this hook should return true for a 64-bit mode\n\
6174	but false for a 32-bit mode.\n\
6175	\n\
6176	The value of @var{abi_id} comes from the @code{predefined_function_abi}\n\
6177	structure that describes the ABI of the call; see the definition of the\n\
6178	structure for more details. If (as is usual) the target uses the same ABI\n\
6179	for all functions in a translation unit, @var{abi_id} is always 0.\n\
6180	\n\
6181	The default implementation returns false, which is correct\n\
6182	for targets that don't have partly call-clobbered registers.",
6183	bool, (unsigned int abi_id, unsigned int regno, machine_mode mode),
6184	hook_bool_uint_uint_mode_false)
6185
6186	DEFHOOK
6187	(get_multilib_abi_name,
6188	"This hook returns name of multilib ABI name.",
6189	const char *, (void),
6190	hook_constcharptr_void_null)
6191
6192	/* Return the smallest number of different values for which it is best to
6193	use a jump-table instead of a tree of conditional branches. */
6194	DEFHOOK
6195	(case_values_threshold,
6196	"This function return the smallest number of different values for which it\n\
6197	is best to use a jump-table instead of a tree of conditional branches.\n\
6198	The default is four for machines with a @code{casesi} instruction and\n\
6199	five otherwise. This is best for most machines.",
6200	unsigned int, (void),
6201	default_case_values_threshold)
6202
6203	DEFHOOK
6204	(starting_frame_offset,
6205	"This hook returns the offset from the frame pointer to the first local\n\
6206	variable slot to be allocated. If @code{FRAME_GROWS_DOWNWARD}, it is the\n\
6207	offset to @emph{end} of the first slot allocated, otherwise it is the\n\
6208	offset to @emph{beginning} of the first slot allocated. The default\n\
6209	implementation returns 0.",
6210	HOST_WIDE_INT, (void),
6211	hook_hwi_void_0)
6212
6213	/* Optional callback to advise the target to compute the frame layout. */
6214	DEFHOOK
6215	(compute_frame_layout,
6216	"This target hook is called once each time the frame layout needs to be\n\
6217	recalculated. The calculations can be cached by the target and can then\n\
6218	be used by @code{INITIAL_ELIMINATION_OFFSET} instead of re-computing the\n\
6219	layout on every invocation of that hook. This is particularly useful\n\
6220	for targets that have an expensive frame layout function. Implementing\n\
6221	this callback is optional.",
6222	void, (void),
6223	hook_void_void)
6224
6225	/* Return true if a function must have and use a frame pointer. */
6226	DEFHOOK
6227	(frame_pointer_required,
6228	"This target hook should return @code{true} if a function must have and use\n\
6229	a frame pointer. This target hook is called in the reload pass. If its return\n\
6230	value is @code{true} the function will have a frame pointer.\n\
6231	\n\
6232	This target hook can in principle examine the current function and decide\n\
6233	according to the facts, but on most machines the constant @code{false} or the\n\
6234	constant @code{true} suffices. Use @code{false} when the machine allows code\n\
6235	to be generated with no frame pointer, and doing so saves some time or space.\n\
6236	Use @code{true} when there is no possible advantage to avoiding a frame\n\
6237	pointer.\n\
6238	\n\
6239	In certain cases, the compiler does not know how to produce valid code\n\
6240	without a frame pointer. The compiler recognizes those cases and\n\
6241	automatically gives the function a frame pointer regardless of what\n\
6242	@code{targetm.frame_pointer_required} returns. You don't need to worry about\n\
6243	them.\n\
6244	\n\
6245	In a function that does not require a frame pointer, the frame pointer\n\
6246	register can be allocated for ordinary usage, unless you mark it as a\n\
6247	fixed register. See @code{FIXED_REGISTERS} for more information.\n\
6248	\n\
6249	Default return value is @code{false}.",
6250	bool, (void),
6251	hook_bool_void_false)
6252
6253	/* Returns true if the compiler is allowed to try to replace register number
6254	from-reg with register number to-reg. */
6255	DEFHOOK
6256	(can_eliminate,
6257	"This target hook should return @code{true} if the compiler is allowed to\n\
6258	try to replace register number @var{from_reg} with register number\n\
6259	@var{to_reg}. This target hook will usually be @code{true}, since most of the\n\
6260	cases preventing register elimination are things that the compiler already\n\
6261	knows about.\n\
6262	\n\
6263	Default return value is @code{true}.",
6264	bool, (const int from_reg, const int to_reg),
6265	hook_bool_const_int_const_int_true)
6266
6267	/* Modify any or all of fixed_regs, call_used_regs, global_regs,
6268	reg_names, and reg_class_contents to account of the vagaries of the
6269	target. */
6270	DEFHOOK
6271	(conditional_register_usage,
6272	"This hook may conditionally modify five variables\n\
6273	@code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
6274	@code{reg_names}, and @code{reg_class_contents}, to take into account\n\
6275	any dependence of these register sets on target flags. The first three\n\
6276	of these are of type @code{char []} (interpreted as boolean vectors).\n\
6277	@code{global_regs} is a @code{const char *[]}, and\n\
6278	@code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
6279	called, @code{fixed_regs}, @code{call_used_regs},\n\
6280	@code{reg_class_contents}, and @code{reg_names} have been initialized\n\
6281	from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
6282	@code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
6283	@code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
6284	@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
6285	command options have been applied.\n\
6286	\n\
6287	@cindex disabling certain registers\n\
6288	@cindex controlling register usage\n\
6289	If the usage of an entire class of registers depends on the target\n\
6290	flags, you may indicate this to GCC by using this macro to modify\n\
6291	@code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
6292	registers in the classes which should not be used by GCC@. Also make\n\
6293	@code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
6294	that shouldn't be used.\n\
6295	\n\
6296	(However, if this class is not included in @code{GENERAL_REGS} and all\n\
6297	of the insn patterns whose constraints permit this class are\n\
6298	controlled by target switches, then GCC will automatically avoid using\n\
6299	these registers when the target switches are opposed to them.)",
6300	void, (void),
6301	hook_void_void)
6302
6303	DEFHOOK
6304	(stack_clash_protection_alloca_probe_range,
6305	"Some targets have an ABI defined interval for which no probing needs to be done.\n\
6306	When a probe does need to be done this same interval is used as the probe distance\n\
6307	up when doing stack clash protection for alloca.\n\
6308	On such targets this value can be set to override the default probing up interval.\n\
6309	Define this variable to return nonzero if such a probe range is required or zero otherwise.\n\
6310	Defining this hook also requires your functions which make use of alloca to have at least 8 byes\n\
6311	of outgoing arguments. If this is not the case the stack will be corrupted.\n\
6312	You need not define this macro if it would always have the value zero.",
6313	HOST_WIDE_INT, (void),
6314	default_stack_clash_protection_alloca_probe_range)
6315
6316
6317	/* Functions specific to the C family of frontends. */
6318	#undef HOOK_PREFIX
6319	#define HOOK_PREFIX "TARGET_C_"
6320	HOOK_VECTOR (TARGET_C, c)
6321
6322	/* ??? Documenting this hook requires a GFDL license grant. */
6323	DEFHOOK_UNDOC
6324	(mode_for_suffix,
6325	"Return machine mode for non-standard constant literal suffix @var{c},\
6326	or VOIDmode if non-standard suffixes are unsupported.",
6327	machine_mode, (char c),
6328	default_mode_for_suffix)
6329
6330	DEFHOOK
6331	(excess_precision,
6332	"Return a value, with the same meaning as the C99 macro\n\
6333	@code{FLT_EVAL_METHOD} that describes which excess precision should be\n\
6334	applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\n\
6335	@code{EXCESS_PRECISION_TYPE_FAST},\n\
6336	@code{EXCESS_PRECISION_TYPE_STANDARD}, or\n\
6337	@code{EXCESS_PRECISION_TYPE_FLOAT16}. For\n\
6338	@code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\n\
6339	precision and range operations will be implictly evaluated in regardless\n\
6340	of the excess precision explicitly added. For\n\
6341	@code{EXCESS_PRECISION_TYPE_STANDARD}, \n\
6342	@code{EXCESS_PRECISION_TYPE_FLOAT16}, and\n\
6343	@code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\n\
6344	explicit excess precision that should be added depending on the\n\
6345	value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{|}16@r{]}}.\n\
6346	Note that unpredictable explicit excess precision does not make sense,\n\
6347	so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\n\
6348	when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD},\n\
6349	@code{EXCESS_PRECISION_TYPE_FLOAT16} or\n\
6350	@code{EXCESS_PRECISION_TYPE_FAST}.",
6351	enum flt_eval_method, (enum excess_precision_type type),
6352	default_excess_precision)
6353
6354	/* Return true if _BitInt(N) is supported and fill details about it into
6355	*INFO. */
6356	DEFHOOK
6357	(bitint_type_info,
6358	"This target hook returns true if @code{_BitInt(@var{N})} is supported and\n\
6359	provides details on it. @code{_BitInt(@var{N})} is to be represented as\n\
6360	series of @code{info->abi_limb_mode}\n\
6361	@code{CEIL (@var{N}, GET_MODE_PRECISION (info->abi_limb_mode))} limbs,\n\
6362	ordered from least significant to most significant if\n\
6363	@code{!info->big_endian}, otherwise from most significant to least\n\
6364	significant. If @code{info->extended} is false, the bits above or equal to\n\
6365	@var{N} are undefined when stored in a register or memory, otherwise they\n\
6366	are zero or sign extended depending on if it is\n\
6367	@code{unsigned _BitInt(@var{N})} or one of @code{_BitInt(@var{N})} or\n\
6368	@code{signed _BitInt(@var{N})}. Alignment of the type is\n\
6369	@code{GET_MODE_ALIGNMENT (info->limb_mode)}.",
6370	bool, (int n, struct bitint_info *info),
6371	default_bitint_type_info)
6372
6373	HOOK_VECTOR_END (c)
6374
6375	/* Functions specific to the C++ frontend. */
6376	#undef HOOK_PREFIX
6377	#define HOOK_PREFIX "TARGET_CXX_"
6378	HOOK_VECTOR (TARGET_CXX, cxx)
6379
6380	/* Return the integer type used for guard variables. */
6381	DEFHOOK
6382	(guard_type,
6383	"Define this hook to override the integer type used for guard variables.\n\
6384	These are used to implement one-time construction of static objects. The\n\
6385	default is long_long_integer_type_node.",
6386	tree, (void),
6387	default_cxx_guard_type)
6388
6389	/* Return true if only the low bit of the guard should be tested. */
6390	DEFHOOK
6391	(guard_mask_bit,
6392	"This hook determines how guard variables are used. It should return\n\
6393	@code{false} (the default) if the first byte should be used. A return value of\n\
6394	@code{true} indicates that only the least significant bit should be used.",
6395	bool, (void),
6396	hook_bool_void_false)
6397
6398	/* Returns the size of the array cookie for an array of type. */
6399	DEFHOOK
6400	(get_cookie_size,
6401	"This hook returns the size of the cookie to use when allocating an array\n\
6402	whose elements have the indicated @var{type}. Assumes that it is already\n\
6403	known that a cookie is needed. The default is\n\
6404	@code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
6405	IA64/Generic C++ ABI@.",
6406	tree, (tree type),
6407	default_cxx_get_cookie_size)
6408
6409	/* Returns true if the element size should be stored in the array cookie. */
6410	DEFHOOK
6411	(cookie_has_size,
6412	"This hook should return @code{true} if the element size should be stored in\n\
6413	array cookies. The default is to return @code{false}.",
6414	bool, (void),
6415	hook_bool_void_false)
6416
6417	/* Allows backends to perform additional processing when
6418	deciding if a class should be exported or imported. */
6419	DEFHOOK
6420	(import_export_class,
6421	"If defined by a backend this hook allows the decision made to export\n\
6422	class @var{type} to be overruled. Upon entry @var{import_export}\n\
6423	will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
6424	to be imported and 0 otherwise. This function should return the\n\
6425	modified value and perform any other actions necessary to support the\n\
6426	backend's targeted operating system.",
6427	int, (tree type, int import_export), NULL)
6428
6429	/* Returns true if constructors and destructors return "this". */
6430	DEFHOOK
6431	(cdtor_returns_this,
6432	"This hook should return @code{true} if constructors and destructors return\n\
6433	the address of the object created/destroyed. The default is to return\n\
6434	@code{false}.",
6435	bool, (void),
6436	hook_bool_void_false)
6437
6438	/* Returns true if the key method for a class can be an inline
6439	function, so long as it is not declared inline in the class
6440	itself. Returning true is the behavior required by the Itanium C++ ABI. */
6441	DEFHOOK
6442	(key_method_may_be_inline,
6443	"This hook returns true if the key method for a class (i.e., the method\n\
6444	which, if defined in the current translation unit, causes the virtual\n\
6445	table to be emitted) may be an inline function. Under the standard\n\
6446	Itanium C++ ABI the key method may be an inline function so long as\n\
6447	the function is not declared inline in the class definition. Under\n\
6448	some variants of the ABI, an inline function can never be the key\n\
6449	method. The default is to return @code{true}.",
6450	bool, (void),
6451	hook_bool_void_true)
6452
6453	DEFHOOK
6454	(determine_class_data_visibility,
6455	"@var{decl} is a virtual table, virtual table table, typeinfo object,\n\
6456	or other similar implicit class data object that will be emitted with\n\
6457	external linkage in this translation unit. No ELF visibility has been\n\
6458	explicitly specified. If the target needs to specify a visibility\n\
6459	other than that of the containing class, use this hook to set\n\
6460	@code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
6461	void, (tree decl),
6462	hook_void_tree)
6463
6464	/* Returns true (the default) if virtual tables and other
6465	similar implicit class data objects are always COMDAT if they
6466	have external linkage. If this hook returns false, then
6467	class data for classes whose virtual table will be emitted in
6468	only one translation unit will not be COMDAT. */
6469	DEFHOOK
6470	(class_data_always_comdat,
6471	"This hook returns true (the default) if virtual tables and other\n\
6472	similar implicit class data objects are always COMDAT if they have\n\
6473	external linkage. If this hook returns false, then class data for\n\
6474	classes whose virtual table will be emitted in only one translation\n\
6475	unit will not be COMDAT.",
6476	bool, (void),
6477	hook_bool_void_true)
6478
6479	/* Returns true (the default) if the RTTI for the basic types,
6480	which is always defined in the C++ runtime, should be COMDAT;
6481	false if it should not be COMDAT. */
6482	DEFHOOK
6483	(library_rtti_comdat,
6484	"This hook returns true (the default) if the RTTI information for\n\
6485	the basic types which is defined in the C++ runtime should always\n\
6486	be COMDAT, false if it should not be COMDAT.",
6487	bool, (void),
6488	hook_bool_void_true)
6489
6490	/* Returns true if __aeabi_atexit should be used to register static
6491	destructors. */
6492	DEFHOOK
6493	(use_aeabi_atexit,
6494	"This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
6495	should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
6496	is in effect. The default is to return false to use @code{__cxa_atexit}.",
6497	bool, (void),
6498	hook_bool_void_false)
6499
6500	/* Returns true if target may use atexit in the same manner as
6501	__cxa_atexit to register static destructors. */
6502	DEFHOOK
6503	(use_atexit_for_cxa_atexit,
6504	"This hook returns true if the target @code{atexit} function can be used\n\
6505	in the same manner as @code{__cxa_atexit} to register C++ static\n\
6506	destructors. This requires that @code{atexit}-registered functions in\n\
6507	shared libraries are run in the correct order when the libraries are\n\
6508	unloaded. The default is to return false.",
6509	bool, (void),
6510	hook_bool_void_false)
6511
6512	DEFHOOK
6513	(adjust_class_at_definition,
6514	"@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\n\
6515	been defined. Use this hook to make adjustments to the class (eg, tweak\n\
6516	visibility or perform any other required target modifications).",
6517	void, (tree type),
6518	hook_void_tree)
6519
6520	DEFHOOK
6521	(decl_mangling_context,
6522	"Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
6523	tree, (const_tree decl),
6524	hook_tree_const_tree_null)
6525
6526	HOOK_VECTOR_END (cxx)
6527
6528	/* Functions and data for emulated TLS support. */
6529	#undef HOOK_PREFIX
6530	#define HOOK_PREFIX "TARGET_EMUTLS_"
6531	HOOK_VECTOR (TARGET_EMUTLS, emutls)
6532
6533	/* Name of the address and common functions. */
6534	DEFHOOKPOD
6535	(get_address,
6536	"Contains the name of the helper function that uses a TLS control\n\
6537	object to locate a TLS instance. The default causes libgcc's\n\
6538	emulated TLS helper function to be used.",
6539	const char *, "__builtin___emutls_get_address")
6540
6541	DEFHOOKPOD
6542	(register_common,
6543	"Contains the name of the helper function that should be used at\n\
6544	program startup to register TLS objects that are implicitly\n\
6545	initialized to zero. If this is @code{NULL}, all TLS objects will\n\
6546	have explicit initializers. The default causes libgcc's emulated TLS\n\
6547	registration function to be used.",
6548	const char *, "__builtin___emutls_register_common")
6549
6550	/* Prefixes for proxy variable and template. */
6551	DEFHOOKPOD
6552	(var_section,
6553	"Contains the name of the section in which TLS control variables should\n\
6554	be placed. The default of @code{NULL} allows these to be placed in\n\
6555	any section.",
6556	const char *, NULL)
6557
6558	DEFHOOKPOD
6559	(tmpl_section,
6560	"Contains the name of the section in which TLS initializers should be\n\
6561	placed. The default of @code{NULL} allows these to be placed in any\n\
6562	section.",
6563	const char *, NULL)
6564
6565	/* Prefixes for proxy variable and template. */
6566	DEFHOOKPOD
6567	(var_prefix,
6568	"Contains the prefix to be prepended to TLS control variable names.\n\
6569	The default of @code{NULL} uses a target-specific prefix.",
6570	const char *, NULL)
6571
6572	DEFHOOKPOD
6573	(tmpl_prefix,
6574	"Contains the prefix to be prepended to TLS initializer objects. The\n\
6575	default of @code{NULL} uses a target-specific prefix.",
6576	const char *, NULL)
6577
6578	/* Function to generate field definitions of the proxy variable. */
6579	DEFHOOK
6580	(var_fields,
6581	"Specifies a function that generates the FIELD_DECLs for a TLS control\n\
6582	object type. @var{type} is the RECORD_TYPE the fields are for and\n\
6583	@var{name} should be filled with the structure tag, if the default of\n\
6584	@code{__emutls_object} is unsuitable. The default creates a type suitable\n\
6585	for libgcc's emulated TLS function.",
6586	tree, (tree type, tree *name),
6587	default_emutls_var_fields)
6588
6589	/* Function to initialize a proxy variable. */
6590	DEFHOOK
6591	(var_init,
6592	"Specifies a function that generates the CONSTRUCTOR to initialize a\n\
6593	TLS control object. @var{var} is the TLS control object, @var{decl}\n\
6594	is the TLS object and @var{tmpl_addr} is the address of the\n\
6595	initializer. The default initializes libgcc's emulated TLS control object.",
6596	tree, (tree var, tree decl, tree tmpl_addr),
6597	default_emutls_var_init)
6598
6599	/* Whether we are allowed to alter the usual alignment of the
6600	proxy variable. */
6601	DEFHOOKPOD
6602	(var_align_fixed,
6603	"Specifies whether the alignment of TLS control variable objects is\n\
6604	fixed and should not be increased as some backends may do to optimize\n\
6605	single objects. The default is false.",
6606	bool, false)
6607
6608	/* Whether we can emit debug information for TLS vars. */
6609	DEFHOOKPOD
6610	(debug_form_tls_address,
6611	"Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
6612	may be used to describe emulated TLS control objects.",
6613	bool, false)
6614
6615	HOOK_VECTOR_END (emutls)
6616
6617	#undef HOOK_PREFIX
6618	#define HOOK_PREFIX "TARGET_OPTION_"
6619	HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
6620
6621	/* Function to validate the attribute((target(...))) strings. If
6622	the option is validated, the hook should also fill in
6623	DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6624	DEFHOOK
6625	(valid_attribute_p,
6626	"This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
6627	allows setting target-specific options on individual functions.\n\
6628	These function-specific options may differ\n\
6629	from the options specified on the command line. The hook should return\n\
6630	@code{true} if the options are valid.\n\
6631	\n\
6632	The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6633	the function declaration to hold a pointer to a target-specific\n\
6634	@code{struct cl_target_option} structure.",
6635	bool, (tree fndecl, tree name, tree args, int flags),
6636	default_target_option_valid_attribute_p)
6637
6638	/* Function to validate the attribute((target_version(...))) strings. If
6639	the option is validated, the hook should also fill in
6640	DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6641	DEFHOOK
6642	(valid_version_attribute_p,
6643	"This hook is called to parse @code{attribute(target_version(\"...\"))},\n\
6644	which allows setting target-specific options on individual function versions.\n\
6645	These function-specific options may differ\n\
6646	from the options specified on the command line. The hook should return\n\
6647	@code{true} if the options are valid.\n\
6648	\n\
6649	The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6650	the function declaration to hold a pointer to a target-specific\n\
6651	@code{struct cl_target_option} structure.",
6652	bool, (tree fndecl, tree name, tree args, int flags),
6653	default_target_option_valid_version_attribute_p)
6654
6655	/* Function to save any extra target state in the target options structure. */
6656	DEFHOOK
6657	(save,
6658	"This hook is called to save any additional target-specific information\n\
6659	in the @code{struct cl_target_option} structure for function-specific\n\
6660	options from the @code{struct gcc_options} structure.\n\
6661	@xref{Option file format}.",
6662	void, (struct cl_target_option *ptr, struct gcc_options *opts,
6663	struct gcc_options *opts_set), NULL)
6664
6665	/* Function to restore any extra target state from the target options
6666	structure. */
6667	DEFHOOK
6668	(restore,
6669	"This hook is called to restore any additional target-specific\n\
6670	information in the @code{struct cl_target_option} structure for\n\
6671	function-specific options to the @code{struct gcc_options} structure.",
6672	void, (struct gcc_options *opts, struct gcc_options *opts_set,
6673	struct cl_target_option *ptr), NULL)
6674
6675	/* Function to update target-specific option information after being
6676	streamed in. */
6677	DEFHOOK
6678	(post_stream_in,
6679	"This hook is called to update target-specific information in the\n\
6680	@code{struct cl_target_option} structure after it is streamed in from\n\
6681	LTO bytecode.",
6682	void, (struct cl_target_option *ptr), NULL)
6683
6684	/* Function to print any extra target state from the target options
6685	structure. */
6686	DEFHOOK
6687	(print,
6688	"This hook is called to print any additional target-specific\n\
6689	information in the @code{struct cl_target_option} structure for\n\
6690	function-specific options.",
6691	void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
6692
6693	/* Function to parse arguments to be validated for #pragma target, and to
6694	change the state if the options are valid. If the first argument is
6695	NULL, the second argument specifies the default options to use. Return
6696	true if the options are valid, and set the current state. */
6697	DEFHOOK
6698	(pragma_parse,
6699	"This target hook parses the options for @code{#pragma GCC target}, which\n\
6700	sets the target-specific options for functions that occur later in the\n\
6701	input stream. The options accepted should be the same as those handled by the\n\
6702	@code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
6703	bool, (tree args, tree pop_target),
6704	default_target_option_pragma_parse)
6705
6706	/* Do option overrides for the target. */
6707	DEFHOOK
6708	(override,
6709	"Sometimes certain combinations of command options do not make sense on\n\
6710	a particular target machine. You can override the hook\n\
6711	@code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
6712	once just after all the command options have been parsed.\n\
6713	\n\
6714	Don't use this hook to turn on various extra optimizations for\n\
6715	@option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
6716	\n\
6717	If you need to do something whenever the optimization level is\n\
6718	changed via the optimize attribute or pragma, see\n\
6719	@code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
6720	void, (void),
6721	hook_void_void)
6722
6723	/* This function returns true if DECL1 and DECL2 are versions of the same
6724	function. DECL1 and DECL2 are function versions if and only if they
6725	have the same function signature and different target specific attributes,
6726	that is, they are compiled for different target machines. */
6727	DEFHOOK
6728	(function_versions,
6729	"This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
6730	versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
6731	versions if and only if they have the same function signature and\n\
6732	different target specific attributes, that is, they are compiled for\n\
6733	different target machines.",
6734	bool, (tree decl1, tree decl2),
6735	hook_bool_tree_tree_false)
6736
6737	/* Function to determine if one function can inline another function. */
6738	#undef HOOK_PREFIX
6739	#define HOOK_PREFIX "TARGET_"
6740	DEFHOOK
6741	(can_inline_p,
6742	"This target hook returns @code{false} if the @var{caller} function\n\
6743	cannot inline @var{callee}, based on target specific information. By\n\
6744	default, inlining is not allowed if the callee function has function\n\
6745	specific target options and the caller does not use the same options.",
6746	bool, (tree caller, tree callee),
6747	default_target_can_inline_p)
6748
6749	DEFHOOK
6750	(update_ipa_fn_target_info,
6751	"Allow target to analyze all gimple statements for the given function to\n\
6752	record and update some target specific information for inlining. A typical\n\
6753	example is that a caller with one isa feature disabled is normally not\n\
6754	allowed to inline a callee with that same isa feature enabled even which is\n\
6755	attributed by always_inline, but with the conservative analysis on all\n\
6756	statements of the callee if we are able to guarantee the callee does not\n\
6757	exploit any instructions from the mismatch isa feature, it would be safe to\n\
6758	allow the caller to inline the callee.\n\
6759	@var{info} is one @code{unsigned int} value to record information in which\n\
6760	one set bit indicates one corresponding feature is detected in the analysis,\n\
6761	@var{stmt} is the statement being analyzed. Return true if target still\n\
6762	need to analyze the subsequent statements, otherwise return false to stop\n\
6763	subsequent analysis.\n\
6764	The default version of this hook returns false.",
6765	bool, (unsigned int& info, const gimple* stmt),
6766	default_update_ipa_fn_target_info)
6767
6768	DEFHOOK
6769	(need_ipa_fn_target_info,
6770	"Allow target to check early whether it is necessary to analyze all gimple\n\
6771	statements in the given function to update target specific information for\n\
6772	inlining. See hook @code{update_ipa_fn_target_info} for usage example of\n\
6773	target specific information. This hook is expected to be invoked ahead of\n\
6774	the iterating with hook @code{update_ipa_fn_target_info}.\n\
6775	@var{decl} is the function being analyzed, @var{info} is the same as what\n\
6776	in hook @code{update_ipa_fn_target_info}, target can do one time update\n\
6777	into @var{info} without iterating for some case. Return true if target\n\
6778	decides to analyze all gimple statements to collect information, otherwise\n\
6779	return false.\n\
6780	The default version of this hook returns false.",
6781	bool, (const_tree decl, unsigned int& info),
6782	default_need_ipa_fn_target_info)
6783
6784	DEFHOOK
6785	(relayout_function,
6786	"This target hook fixes function @var{fndecl} after attributes are processed.\n\
6787	Default does nothing. On ARM, the default function's alignment is updated\n\
6788	with the attribute target.",
6789	void, (tree fndecl),
6790	hook_void_tree)
6791
6792	HOOK_VECTOR_END (target_option)
6793
6794	/* For targets that need to mark extra registers as live on entry to
6795	the function, they should define this target hook and set their
6796	bits in the bitmap passed in. */
6797	DEFHOOK
6798	(extra_live_on_entry,
6799	"Add any hard registers to @var{regs} that are live on entry to the\n\
6800	function. This hook only needs to be defined to provide registers that\n\
6801	cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
6802	registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
6803	TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
6804	FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
6805	void, (bitmap regs),
6806	hook_void_bitmap)
6807
6808	/* Targets should define this target hook to mark that non-callee clobbers are
6809	present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
6810	definition. */
6811	DEFHOOKPOD
6812	(call_fusage_contains_non_callee_clobbers,
6813	"Set to true if each call that binds to a local definition explicitly\n\
6814	clobbers or sets all non-fixed registers modified by performing the call.\n\
6815	That is, by the call pattern itself, or by code that might be inserted by the\n\
6816	linker (e.g.@: stubs, veneers, branch islands), but not including those\n\
6817	modifiable by the callee. The affected registers may be mentioned explicitly\n\
6818	in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
6819	The default version of this hook is set to false. The purpose of this hook\n\
6820	is to enable the fipa-ra optimization.",
6821	bool,
6822	false)
6823
6824	/* Fill in additional registers set up by prologue into a regset. */
6825	DEFHOOK
6826	(set_up_by_prologue,
6827	"This hook should add additional registers that are computed by the prologue\n\
6828	to the hard regset for shrink-wrapping optimization purposes.",
6829	void, (struct hard_reg_set_container *),
6830	NULL)
6831
6832	/* For targets that have attributes that can affect whether a
6833	function's return statements need checking. For instance a 'naked'
6834	function attribute. */
6835	DEFHOOK
6836	(warn_func_return,
6837	"True if a function's return statements should be checked for matching\n\
6838	the function's return type. This includes checking for falling off the end\n\
6839	of a non-void function. Return false if no such check should be made.",
6840	bool, (tree),
6841	hook_bool_tree_true)
6842
6843	#undef HOOK_PREFIX
6844	#define HOOK_PREFIX "TARGET_SHRINK_WRAP_"
6845	HOOK_VECTOR (TARGET_SHRINK_WRAP_HOOKS, shrink_wrap)
6846
6847	DEFHOOK
6848	(get_separate_components,
6849	"This hook should return an @code{sbitmap} with the bits set for those\n\
6850	components that can be separately shrink-wrapped in the current function.\n\
6851	Return @code{NULL} if the current function should not get any separate\n\
6852	shrink-wrapping.\n\
6853	Don't define this hook if it would always return @code{NULL}.\n\
6854	If it is defined, the other hooks in this group have to be defined as well.",
6855	sbitmap, (void),
6856	NULL)
6857
6858	DEFHOOK
6859	(components_for_bb,
6860	"This hook should return an @code{sbitmap} with the bits set for those\n\
6861	components where either the prologue component has to be executed before\n\
6862	the @code{basic_block}, or the epilogue component after it, or both.",
6863	sbitmap, (basic_block),
6864	NULL)
6865
6866	DEFHOOK
6867	(disqualify_components,
6868	"This hook should clear the bits in the @var{components} bitmap for those\n\
6869	components in @var{edge_components} that the target cannot handle on edge\n\
6870	@var{e}, where @var{is_prologue} says if this is for a prologue or an\n\
6871	epilogue instead.",
6872	void, (sbitmap components, edge e, sbitmap edge_components, bool is_prologue),
6873	NULL)
6874
6875	DEFHOOK
6876	(emit_prologue_components,
6877	"Emit prologue insns for the components indicated by the parameter.",
6878	void, (sbitmap),
6879	NULL)
6880
6881	DEFHOOK
6882	(emit_epilogue_components,
6883	"Emit epilogue insns for the components indicated by the parameter.",
6884	void, (sbitmap),
6885	NULL)
6886
6887	DEFHOOK
6888	(set_handled_components,
6889	"Mark the components in the parameter as handled, so that the\n\
6890	@code{prologue} and @code{epilogue} named patterns know to ignore those\n\
6891	components. The target code should not hang on to the @code{sbitmap}, it\n\
6892	will be deleted after this call.",
6893	void, (sbitmap),
6894	NULL)
6895
6896	HOOK_VECTOR_END (shrink_wrap)
6897	#undef HOOK_PREFIX
6898	#define HOOK_PREFIX "TARGET_"
6899
6900	/* Determine the type of unwind info to emit for debugging. */
6901	DEFHOOK
6902	(debug_unwind_info,
6903	"This hook defines the mechanism that will be used for describing frame\n\
6904	unwind information to the debugger. Normally the hook will return\n\
6905	@code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
6906	return @code{UI_NONE} otherwise.\n\
6907	\n\
6908	A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
6909	is disabled in order to always output DWARF 2 frame information.\n\
6910	\n\
6911	A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
6912	This will suppress generation of the normal debug frame unwind information.",
6913	enum unwind_info_type, (void),
6914	default_debug_unwind_info)
6915
6916	DEFHOOK
6917	(reset_location_view,
6918	"This hook, if defined, enables -ginternal-reset-location-views, and\n\
6919	uses its result to override cases in which the estimated min insn\n\
6920	length might be nonzero even when a PC advance (i.e., a view reset)\n\
6921	cannot be taken for granted.\n\
6922	\n\
6923	If the hook is defined, it must return a positive value to indicate\n\
6924	the insn definitely advances the PC, and so the view number can be\n\
6925	safely assumed to be reset; a negative value to mean the insn\n\
6926	definitely does not advance the PC, and os the view number must not\n\
6927	be reset; or zero to decide based on the estimated insn length.\n\
6928	\n\
6929	If insn length is to be regarded as reliable, set the hook to\n\
6930	@code{hook_int_rtx_insn_0}.",
6931	int, (rtx_insn *), NULL)
6932
6933	/* The code parameter should be of type enum rtx_code but this is not
6934	defined at this time. */
6935	DEFHOOK
6936	(canonicalize_comparison,
6937	"On some machines not all possible comparisons are defined, but you can\n\
6938	convert an invalid comparison into a valid one. For example, the Alpha\n\
6939	does not have a @code{GT} comparison, but you can use an @code{LT}\n\
6940	comparison instead and swap the order of the operands.\n\
6941	\n\
6942	On such machines, implement this hook to do any required conversions.\n\
6943	@var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
6944	are the left and right operands of the comparison, respectively. If\n\
6945	@var{op0_preserve_value} is @code{true} the implementation is not\n\
6946	allowed to change the value of @var{op0} since the value might be used\n\
6947	in RTXs which aren't comparisons. E.g. the implementation is not\n\
6948	allowed to swap operands in that case.\n\
6949	\n\
6950	GCC will not assume that the comparison resulting from this macro is\n\
6951	valid but will see if the resulting insn matches a pattern in the\n\
6952	@file{md} file.\n\
6953	\n\
6954	You need not to implement this hook if it would never change the\n\
6955	comparison code or operands.",
6956	void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
6957	default_canonicalize_comparison)
6958
6959	DEFHOOK
6960	(min_arithmetic_precision,
6961	"On some RISC architectures with 64-bit registers, the processor also\n\
6962	maintains 32-bit condition codes that make it possible to do real 32-bit\n\
6963	arithmetic, although the operations are performed on the full registers.\n\
6964	\n\
6965	On such architectures, defining this hook to 32 tells the compiler to try\n\
6966	using 32-bit arithmetical operations setting the condition codes instead\n\
6967	of doing full 64-bit arithmetic.\n\
6968	\n\
6969	More generally, define this hook on RISC architectures if you want the\n\
6970	compiler to try using arithmetical operations setting the condition codes\n\
6971	with a precision lower than the word precision.\n\
6972	\n\
6973	You need not define this hook if @code{WORD_REGISTER_OPERATIONS} is not\n\
6974	defined to 1.",
6975	unsigned int, (void), default_min_arithmetic_precision)
6976
6977	DEFHOOKPOD
6978	(atomic_test_and_set_trueval,
6979	"This value should be set if the result written by\n\
6980	@code{atomic_test_and_set} is not exactly 1, i.e.@: the\n\
6981	@code{bool} @code{true}.",
6982	unsigned char, 1)
6983
6984	/* Return an unsigned int representing the alignment (in bits) of the atomic
6985	type which maps to machine MODE. This allows alignment to be overridden
6986	as needed. */
6987	DEFHOOK
6988	(atomic_align_for_mode,
6989	"If defined, this function returns an appropriate alignment in bits for an\n\
6990	atomic object of machine_mode @var{mode}. If 0 is returned then the\n\
6991	default alignment for the specified mode is used.",
6992	unsigned int, (machine_mode mode),
6993	hook_uint_mode_0)
6994
6995	DEFHOOK
6996	(atomic_assign_expand_fenv,
6997	"ISO C11 requires atomic compound assignments that may raise floating-point\n\
6998	exceptions to raise exceptions corresponding to the arithmetic operation\n\
6999	whose result was successfully stored in a compare-and-exchange sequence.\n\
7000	This requires code equivalent to calls to @code{feholdexcept},\n\
7001	@code{feclearexcept} and @code{feupdateenv} to be generated at\n\
7002	appropriate points in the compare-and-exchange sequence. This hook should\n\
7003	set @code{*@var{hold}} to an expression equivalent to the call to\n\
7004	@code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\n\
7005	the call to @code{feclearexcept} and @code{*@var{update}} to an expression\n\
7006	equivalent to the call to @code{feupdateenv}. The three expressions are\n\
7007	@code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\n\
7008	if no code is required in a particular place. The default implementation\n\
7009	leaves all three expressions as @code{NULL_TREE}. The\n\
7010	@code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\n\
7011	as part of the code generated in @code{*@var{update}}.",
7012	void, (tree *hold, tree *clear, tree *update),
7013	default_atomic_assign_expand_fenv)
7014
7015	/* Leave the boolean fields at the end. */
7016
7017	/* True if we can create zeroed data by switching to a BSS section
7018	and then using ASM_OUTPUT_SKIP to allocate the space. */
7019	DEFHOOKPOD
7020	(have_switchable_bss_sections,
7021	"This flag is true if we can create zeroed data by switching to a BSS\n\
7022	section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
7023	This is true on most ELF targets.",
7024	bool, false)
7025
7026	/* True if "native" constructors and destructors are supported,
7027	false if we're using collect2 for the job. */
7028	DEFHOOKPOD
7029	(have_ctors_dtors,
7030	"This value is true if the target supports some ``native'' method of\n\
7031	collecting constructors and destructors to be run at startup and exit.\n\
7032	It is false if we must use @command{collect2}.",
7033	bool, false)
7034
7035	/* True if the target wants DTORs to be run from cxa_atexit. */
7036	DEFHOOKPOD
7037	(dtors_from_cxa_atexit,
7038	"This value is true if the target wants destructors to be queued to be\n\
7039	run from __cxa_atexit. If this is the case then, for each priority level,\n\
7040	a new constructor will be entered that registers the destructors for that\n\
7041	level with __cxa_atexit (and there will be no destructors emitted).\n\
7042	It is false the method implied by @code{have_ctors_dtors} is used.",
7043	bool, false)
7044
7045	/* True if thread-local storage is supported. */
7046	DEFHOOKPOD
7047	(have_tls,
7048	"Contains the value true if the target supports thread-local storage.\n\
7049	The default value is false.",
7050	bool, false)
7051
7052	/* True if a small readonly data section is supported. */
7053	DEFHOOKPOD
7054	(have_srodata_section,
7055	"Contains the value true if the target places read-only\n\
7056	``small data'' into a separate section. The default value is false.",
7057	bool, false)
7058
7059	/* True if EH frame info sections should be zero-terminated. */
7060	DEFHOOKPOD
7061	(terminate_dw2_eh_frame_info,
7062	"Contains the value true if the target should add a zero word onto the\n\
7063	end of a Dwarf-2 frame info section when used for exception handling.\n\
7064	Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
7065	true otherwise.",
7066	bool, true)
7067
7068	/* True if #NO_APP should be emitted at the beginning of assembly output. */
7069	DEFHOOKPOD
7070	(asm_file_start_app_off,
7071	"If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
7072	printed as the very first line in the assembly file, unless\n\
7073	@option{-fverbose-asm} is in effect. (If that macro has been defined\n\
7074	to the empty string, this variable has no effect.) With the normal\n\
7075	definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
7076	assembler that it need not bother stripping comments or extra\n\
7077	whitespace from its input. This allows it to work a bit faster.\n\
7078	\n\
7079	The default is false. You should not set it to true unless you have\n\
7080	verified that your port does not generate any extra whitespace or\n\
7081	comments that will cause GAS to issue errors in NO_APP mode.",
7082	bool, false)
7083
7084	/* True if output_file_directive should be called for main_input_filename
7085	at the beginning of assembly output. */
7086	DEFHOOKPOD
7087	(asm_file_start_file_directive,
7088	"If this flag is true, @code{output_file_directive} will be called\n\
7089	for the primary source file, immediately after printing\n\
7090	@code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
7091	this to be done. The default is false.",
7092	bool, false)
7093
7094	/* Returns true if we should generate exception tables for use with the
7095	ARM EABI. The effects the encoding of function exception specifications. */
7096	DEFHOOKPOD
7097	(arm_eabi_unwinder,
7098	"This flag should be set to @code{true} on targets that use an ARM EABI\n\
7099	based unwinding library, and @code{false} on other targets. This effects\n\
7100	the format of unwinding tables, and how the unwinder in entered after\n\
7101	running a cleanup. The default is @code{false}.",
7102	bool, false)
7103
7104	DEFHOOKPOD
7105	(want_debug_pub_sections,
7106	"True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\n\
7107	should be emitted. These sections are not used on most platforms, and\n\
7108	in particular GDB does not use them.",
7109	bool, false)
7110
7111	DEFHOOKPOD
7112	(delay_sched2,
7113	"True if sched2 is not to be run at its normal place.\n\
7114	This usually means it will be run as part of machine-specific reorg.",
7115	bool, false)
7116
7117	DEFHOOKPOD
7118	(delay_vartrack,
7119	"True if vartrack is not to be run at its normal place.\n\
7120	This usually means it will be run as part of machine-specific reorg.",
7121	bool, false)
7122
7123	DEFHOOKPOD
7124	(no_register_allocation,
7125	"True if register allocation and the passes\n\
7126	following it should not be run. Usually true only for virtual assembler\n\
7127	targets.",
7128	bool, false)
7129
7130	/* Leave the boolean fields at the end. */
7131
7132	/* Functions related to mode switching. */
7133	#undef HOOK_PREFIX
7134	#define HOOK_PREFIX "TARGET_MODE_"
7135	HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
7136
7137	DEFHOOK
7138	(emit,
7139	"Generate one or more insns to set @var{entity} to @var{mode}.\n\
7140	@var{hard_reg_live} is the set of hard registers live at the point where\n\
7141	the insn(s) are to be inserted. @var{prev_moxde} indicates the mode\n\
7142	to switch from, or is the number of modes if the previous mode is not\n\
7143	known. Sets of a lower numbered entity will be emitted before\n\
7144	sets of a higher numbered entity to a mode of the same or lower priority.",
7145	void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
7146
7147	DEFHOOK
7148	(needed,
7149	"@var{entity} is an integer specifying a mode-switched entity.\n\
7150	If @code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this hook\n\
7151	to return the mode that @var{entity} must be switched into prior to the\n\
7152	execution of @var{insn}, or the number of modes if @var{insn} has no\n\
7153	such requirement. @var{regs_live} contains the set of hard registers\n\
7154	that are live before @var{insn}.",
7155	int, (int entity, rtx_insn *insn, HARD_REG_SET regs_live), NULL)
7156
7157	DEFHOOK
7158	(after,
7159	"@var{entity} is an integer specifying a mode-switched entity.\n\
7160	If this hook is defined, it is evaluated for every @var{insn} during mode\n\
7161	switching. It returns the mode that @var{entity} is in after @var{insn}\n\
7162	has been executed. @var{mode} is the mode that @var{entity} was in\n\
7163	before @var{insn} was executed, taking account of @var{TARGET_MODE_NEEDED}.\n\
7164	@var{regs_live} is the set of hard registers that are live after @var{insn}\n\
7165	has been executed.\n\
7166	\n\
7167	@var{mode} is equal to the number of modes defined for @var{entity}\n\
7168	if the mode before @var{insn} is unknown. The hook should likewise return\n\
7169	the number of modes if it does not know what mode @var{entity} has after\n\
7170	@var{insn}.\n\
7171	\n\
7172	Not defining the hook is equivalent to returning @var{mode}.",
7173	int, (int entity, int mode, rtx_insn *insn, HARD_REG_SET regs_live), NULL)
7174
7175	DEFHOOK
7176	(confluence,
7177	"By default, the mode-switching pass assumes that a given entity's modes\n\
7178	are mutually exclusive. This means that the pass can only tell\n\
7179	@code{TARGET_MODE_EMIT} about an entity's previous mode if all\n\
7180	incoming paths of execution leave the entity in the same state.\n\
7181	\n\
7182	However, some entities might have overlapping, non-exclusive modes,\n\
7183	so that it is sometimes possible to represent ``mode @var{mode1} or mode\n\
7184	@var{mode2}'' with something more specific than ``mode not known''.\n\
7185	If this is true for at least one entity, you should define this hook\n\
7186	and make it return a mode that includes @var{mode1} and @var{mode2}\n\
7187	as possibilities. (The mode can include other possibilities too.)\n\
7188	The hook should return the number of modes if no suitable mode exists\n\
7189	for the given arguments.",
7190	int, (int entity, int mode1, int mode2), NULL)
7191
7192	DEFHOOK
7193	(backprop,
7194	"If defined, the mode-switching pass uses this hook to back-propagate mode\n\
7195	requirements through blocks that have no mode requirements of their own.\n\
7196	Specifically, @var{mode1} is the mode that @var{entity} has on exit\n\
7197	from a block B1 (say) and @var{mode2} is the mode that the next block\n\
7198	requires @var{entity} to have. B1 does not have any mode requirements\n\
7199	of its own.\n\
7200	\n\
7201	The hook should return the mode that it prefers or requires @var{entity}\n\
7202	to have in B1, or the number of modes if there is no such requirement.\n\
7203	If the hook returns a required mode for more than one of B1's outgoing\n\
7204	edges, those modes are combined as for @code{TARGET_MODE_CONFLUENCE}.\n\
7205	\n\
7206	For example, suppose there is a ``one-shot'' entity that,\n\
7207	for a given execution of a function, either stays off or makes exactly\n\
7208	one transition from off to on. It is safe to make the transition at any\n\
7209	time, but it is better not to do so unnecessarily. This hook allows the\n\
7210	function to manage such an entity without having to track its state at\n\
7211	runtime. Specifically. the entity would have two modes, 0 for off and\n\
7212	1 for on, with 2 representing ``don't know''. The system is forbidden from\n\
7213	transitioning from 2 to 1, since 2 represents the possibility that the\n\
7214	entity is already on (and the aim is to avoid having to emit code to\n\
7215	check for that case). This hook would therefore return 1 when @var{mode1}\n\
7216	is 2 and @var{mode2} is 1, which would force the entity to be on in the\n\
7217	source block. Applying this inductively would remove all transitions\n\
7218	in which the previous state is unknown.",
7219	int, (int entity, int mode1, int mode2), NULL)
7220
7221	DEFHOOK
7222	(entry,
7223	"If this hook is defined, it is evaluated for every @var{entity} that\n\
7224	needs mode switching. It should return the mode that @var{entity} is\n\
7225	guaranteed to be in on entry to the function, or the number of modes\n\
7226	if there is no such guarantee.\n\
7227	If @code{TARGET_MODE_ENTRY} is defined then @code{TARGET_MODE_EXIT}\n\
7228	must be defined.",
7229	int, (int entity), NULL)
7230
7231	DEFHOOK
7232	(exit,
7233	"If this hook is defined, it is evaluated for every @var{entity} that\n\
7234	needs mode switching. It should return the mode that @var{entity} must\n\
7235	be in on return from the function, or the number of modes if there is no\n\
7236	such requirement.\n\
7237	If @code{TARGET_MODE_EXIT} is defined then @code{TARGET_MODE_ENTRY}\n\
7238	must be defined.",
7239	int, (int entity), NULL)
7240
7241	DEFHOOK
7242	(eh_handler,
7243	"If this hook is defined, it should return the mode that @var{entity} is\n\
7244	guaranteed to be in on entry to an exception handler, or the number of modes\n\
7245	if there is no such guarantee.",
7246	int, (int entity), NULL)
7247
7248	DEFHOOK
7249	(priority,
7250	"This hook specifies the order in which modes for @var{entity}\n\
7251	are processed. 0 is the highest priority,\n\
7252	@code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the lowest.\n\
7253	The hook returns an integer designating a mode\n\
7254	for @var{entity}. For any fixed @var{entity}, @code{mode_priority}\n\
7255	(@var{entity}, @var{n}) shall be a bijection in 0 @dots{}\n\
7256	@code{num_modes_for_mode_switching[@var{entity}] - 1}.",
7257	int, (int entity, int n), NULL)
7258
7259	HOOK_VECTOR_END (mode_switching)
7260
7261	#undef HOOK_PREFIX
7262	#define HOOK_PREFIX "TARGET_MEMTAG_"
7263	HOOK_VECTOR (TARGET_MEMTAG_, memtag)
7264
7265	DEFHOOK
7266	(can_tag_addresses,
7267	"True if the backend architecture naturally supports ignoring some region\n\
7268	of pointers. This feature means that @option{-fsanitize=hwaddress} can\n\
7269	work.\n\
7270	\n\
7271	At preset, this feature does not support address spaces. It also requires\n\
7272	@code{Pmode} to be the same as @code{ptr_mode}.",
7273	bool, (), default_memtag_can_tag_addresses)
7274
7275	DEFHOOK
7276	(tag_size,
7277	"Return the size of a tag (in bits) for this platform.\n\
7278	\n\
7279	The default returns 8.",
7280	uint8_t, (), default_memtag_tag_size)
7281
7282	DEFHOOK
7283	(granule_size,
7284	"Return the size in real memory that each byte in shadow memory refers to.\n\
7285	I.e. if a variable is @var{X} bytes long in memory, then this hook should\n\
7286	return the value @var{Y} such that the tag in shadow memory spans\n\
7287	@var{X}/@var{Y} bytes.\n\
7288	\n\
7289	Most variables will need to be aligned to this amount since two variables\n\
7290	that are neighbors in memory and share a tag granule would need to share\n\
7291	the same tag.\n\
7292	\n\
7293	The default returns 16.",
7294	uint8_t, (), default_memtag_granule_size)
7295
7296	DEFHOOK
7297	(insert_random_tag,
7298	"Return an RTX representing the value of @var{untagged} but with a\n\
7299	(possibly) random tag in it.\n\
7300	Put that value into @var{target} if it is convenient to do so.\n\
7301	This function is used to generate a tagged base for the current stack frame.",
7302	rtx, (rtx untagged, rtx target), default_memtag_insert_random_tag)
7303
7304	DEFHOOK
7305	(add_tag,
7306	"Return an RTX that represents the result of adding @var{addr_offset} to\n\
7307	the address in pointer @var{base} and @var{tag_offset} to the tag in pointer\n\
7308	@var{base}.\n\
7309	The resulting RTX must either be a valid memory address or be able to get\n\
7310	put into an operand with @code{force_operand}.\n\
7311	\n\
7312	Unlike other memtag hooks, this must return an expression and not emit any\n\
7313	RTL.",
7314	rtx, (rtx base, poly_int64 addr_offset, uint8_t tag_offset),
7315	default_memtag_add_tag)
7316
7317	DEFHOOK
7318	(set_tag,
7319	"Return an RTX representing @var{untagged_base} but with the tag @var{tag}.\n\
7320	Try and store this in @var{target} if convenient.\n\
7321	@var{untagged_base} is required to have a zero tag when this hook is called.\n\
7322	The default of this hook is to set the top byte of @var{untagged_base} to\n\
7323	@var{tag}.",
7324	rtx, (rtx untagged_base, rtx tag, rtx target), default_memtag_set_tag)
7325
7326	DEFHOOK
7327	(extract_tag,
7328	"Return an RTX representing the tag stored in @var{tagged_pointer}.\n\
7329	Store the result in @var{target} if it is convenient.\n\
7330	The default represents the top byte of the original pointer.",
7331	rtx, (rtx tagged_pointer, rtx target), default_memtag_extract_tag)
7332
7333	DEFHOOK
7334	(untagged_pointer,
7335	"Return an RTX representing @var{tagged_pointer} with its tag set to zero.\n\
7336	Store the result in @var{target} if convenient.\n\
7337	The default clears the top byte of the original pointer.",
7338	rtx, (rtx tagged_pointer, rtx target), default_memtag_untagged_pointer)
7339
7340	HOOK_VECTOR_END (memtag)
7341	#undef HOOK_PREFIX
7342	#define HOOK_PREFIX "TARGET_"
7343
7344	#define DEF_TARGET_INSN(NAME, PROTO) \
7345	DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
7346	#include "target-insns.def"
7347	#undef DEF_TARGET_INSN
7348
7349	#define DEF_TARGET_INSN(NAME, PROTO) \
7350	DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
7351	#include "target-insns.def"
7352	#undef DEF_TARGET_INSN
7353
7354	#define DEF_TARGET_INSN(NAME, PROTO) \
7355	DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
7356	#include "target-insns.def"
7357	#undef DEF_TARGET_INSN
7358
7359	DEFHOOK
7360	(run_target_selftests,
7361	"If selftests are enabled, run any selftests for this target.",
7362	void, (void),
7363	NULL)
7364
7365	/* This value represents whether the shadow call stack is implemented on
7366	the target platform. */
7367	DEFHOOKPOD
7368	(have_shadow_call_stack,
7369	"This value is true if the target platform supports\n\
7370	@option{-fsanitize=shadow-call-stack}. The default value is false.",
7371	bool, false)
7372
7373	/* This value represents whether libatomic is available on
7374	the target platform. */
7375	DEFHOOKPOD
7376	(have_libatomic,
7377	"This value is true if the target platform supports\n\
7378	libatomic. The default value is false.",
7379	bool, false)
7380
7381	/* Close the 'struct gcc_target' definition. */
7382	HOOK_VECTOR_END (C90_EMPTY_HACK)
7383
7384