1/* Target hook definitions.
2 Copyright (C) 2001-2017 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
29HOOK_VECTOR (TARGET_INITIALIZER, gcc_target)
30
31/* Functions that output assembler for the target. */
32#define HOOK_PREFIX "TARGET_ASM_"
33HOOK_VECTOR (TARGET_ASM_OUT, asm_out)
34
35/* Opening and closing parentheses for asm expression grouping. */
36DEFHOOKPOD
37(open_paren,
38 "These target hooks are C string constants, describing the syntax in the\n\
39assembler for grouping arithmetic expressions. If not overridden, they\n\
40default to normal parentheses, which is correct for most assemblers.",
41 const char *, "(")
42DEFHOOKPODX (close_paren, const char *, ")")
43
44/* Assembler instructions for creating various kinds of integer object. */
45DEFHOOKPOD
46(byte_op,
47 "@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_HI_OP\n\
48@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_SI_OP\n\
49@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP\n\
50@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP\n\
51@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP\n\
52@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP\n\
53@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP\n\
54@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP\n\
55These hooks specify assembly directives for creating certain kinds\n\
56of integer object. The @code{TARGET_ASM_BYTE_OP} directive creates a\n\
57byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an\n\
58aligned two-byte object, and so on. Any of the hooks may be\n\
59@code{NULL}, indicating that no suitable directive is available.\n\
60\n\
61The compiler will print these strings at the start of a new line,\n\
62followed immediately by the object's initial value. In most cases,\n\
63the string should contain a tab, a pseudo-op, and then another tab.",
64 const char *, "\t.byte\t")
65DEFHOOKPOD (aligned_op, "*", struct asm_int_op, TARGET_ASM_ALIGNED_INT_OP)
66DEFHOOKPOD (unaligned_op, "*", struct asm_int_op, TARGET_ASM_UNALIGNED_INT_OP)
67
68/* The maximum number of bytes to skip when applying
69 LABEL_ALIGN_AFTER_BARRIER. */
70DEFHOOK
71(label_align_after_barrier_max_skip,
72 "The maximum number of bytes to skip before @var{label} when applying\n\
73@code{LABEL_ALIGN_AFTER_BARRIER}. This works only if\n\
74@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
75 int, (rtx_insn *label),
76 default_label_align_after_barrier_max_skip)
77
78/* The maximum number of bytes to skip when applying
79 LOOP_ALIGN. */
80DEFHOOK
81(loop_align_max_skip,
82 "The maximum number of bytes to skip when applying @code{LOOP_ALIGN} to\n\
83@var{label}. This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is\n\
84defined.",
85 int, (rtx_insn *label),
86 default_loop_align_max_skip)
87
88/* The maximum number of bytes to skip when applying
89 LABEL_ALIGN. */
90DEFHOOK
91(label_align_max_skip,
92 "The maximum number of bytes to skip when applying @code{LABEL_ALIGN}\n\
93to @var{label}. This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN}\n\
94is defined.",
95 int, (rtx_insn *label),
96 default_label_align_max_skip)
97
98/* The maximum number of bytes to skip when applying
99 JUMP_ALIGN. */
100DEFHOOK
101(jump_align_max_skip,
102 "The maximum number of bytes to skip before @var{label} when applying\n\
103@code{JUMP_ALIGN}. This works only if\n\
104@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
105 int, (rtx_insn *label),
106 default_jump_align_max_skip)
107
108/* Try to output the assembler code for an integer object whose
109 value is given by X. SIZE is the size of the object in bytes and
110 ALIGNED_P indicates whether it is aligned. Return true if
111 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
112 and UNALIGNED_OP are NULL. */
113DEFHOOK
114(integer,
115 "The @code{assemble_integer} function uses this hook to output an\n\
116integer object. @var{x} is the object's value, @var{size} is its size\n\
117in bytes and @var{aligned_p} indicates whether it is aligned. The\n\
118function should return @code{true} if it was able to output the\n\
119object. If it returns false, @code{assemble_integer} will try to\n\
120split the object into smaller parts.\n\
121\n\
122The default implementation of this hook will use the\n\
123@code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}\n\
124when the relevant string is @code{NULL}.",
125 /* Only handles cases for which BYTE_OP, ALIGNED_OP and UNALIGNED_OP are
126 NULL. */
127 bool, (rtx x, unsigned int size, int aligned_p),
128 default_assemble_integer)
129
130/* Notify the backend that we have completed emitting the data for a
131 decl. */
132DEFHOOK
133(decl_end,
134 "Define this hook if the target assembler requires a special marker to\n\
135terminate an initialized variable declaration.",
136 void, (void),
137 hook_void_void)
138
139/* Output code that will globalize a label. */
140DEFHOOK
141(globalize_label,
142 "This target hook is a function to output to the stdio stream\n\
143@var{stream} some commands that will make the label @var{name} global;\n\
144that is, available for reference from other files.\n\
145\n\
146The default implementation relies on a proper definition of\n\
147@code{GLOBAL_ASM_OP}.",
148 void, (FILE *stream, const char *name),
149 default_globalize_label)
150
151/* Output code that will globalize a declaration. */
152DEFHOOK
153(globalize_decl_name,
154 "This target hook is a function to output to the stdio stream\n\
155@var{stream} some commands that will make the name associated with @var{decl}\n\
156global; that is, available for reference from other files.\n\
157\n\
158The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
159 void, (FILE *stream, tree decl), default_globalize_decl_name)
160
161/* Output code that will declare an external variable. */
162DEFHOOK
163(assemble_undefined_decl,
164 "This target hook is a function to output to the stdio stream\n\
165@var{stream} some commands that will declare the name associated with\n\
166@var{decl} which is not defined in the current translation unit. Most\n\
167assemblers do not require anything to be output in this case.",
168 void, (FILE *stream, const char *name, const_tree decl),
169 hook_void_FILEptr_constcharptr_const_tree)
170
171/* Output code that will emit a label for unwind info, if this
172 target requires such labels. Second argument is the decl the
173 unwind info is associated with, third is a boolean: true if
174 this is for exception handling, fourth is a boolean: true if
175 this is only a placeholder for an omitted FDE. */
176DEFHOOK
177(emit_unwind_label,
178 "This target hook emits a label at the beginning of each FDE@. It\n\
179should be defined on targets where FDEs need special labels, and it\n\
180should write the appropriate label, for the FDE associated with the\n\
181function declaration @var{decl}, to the stdio stream @var{stream}.\n\
182The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
183exception table. The fourth argument, @var{empty}, is a boolean:\n\
184true if this is a placeholder label for an omitted FDE@.\n\
185\n\
186The default is that FDEs are not given nonlocal labels.",
187 void, (FILE *stream, tree decl, int for_eh, int empty),
188 default_emit_unwind_label)
189
190/* Output code that will emit a label to divide up the exception table. */
191DEFHOOK
192(emit_except_table_label,
193 "This target hook emits a label at the beginning of the exception table.\n\
194It should be defined on targets where it is desirable for the table\n\
195to be broken up according to function.\n\
196\n\
197The default is that no label is emitted.",
198 void, (FILE *stream),
199 default_emit_except_table_label)
200
201/* Emit a directive for setting the personality for the function. */
202DEFHOOK
203(emit_except_personality,
204 "If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\
205 used to emit a directive to install a personality hook into the unwind\
206 info. This hook should not be used if dwarf2 unwind info is used.",
207 void, (rtx personality),
208 NULL)
209
210/* Emit any directives required to unwind this instruction. */
211DEFHOOK
212(unwind_emit,
213 "This target hook emits assembly directives required to unwind the\n\
214given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
215returns @code{UI_TARGET}.",
216 void, (FILE *stream, rtx_insn *insn),
217 NULL)
218
219DEFHOOKPOD
220(unwind_emit_before_insn,
221 "True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\
222 the assembly for @var{insn} has been emitted, false if the hook should\
223 be called afterward.",
224 bool, true)
225
226/* Generate an internal label.
227 For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL. */
228DEFHOOK_UNDOC
229(generate_internal_label,
230 "",
231 void, (char *buf, const char *prefix, unsigned long labelno),
232 default_generate_internal_label)
233
234/* Output an internal label. */
235DEFHOOK
236(internal_label,
237 "A function to output to the stdio stream @var{stream} a label whose\n\
238name is made from the string @var{prefix} and the number @var{labelno}.\n\
239\n\
240It is absolutely essential that these labels be distinct from the labels\n\
241used for user-level functions and variables. Otherwise, certain programs\n\
242will have name conflicts with internal labels.\n\
243\n\
244It is desirable to exclude internal labels from the symbol table of the\n\
245object file. Most assemblers have a naming convention for labels that\n\
246should be excluded; on many systems, the letter @samp{L} at the\n\
247beginning of a label has this effect. You should find out what\n\
248convention your system uses, and follow it.\n\
249\n\
250The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.",
251 void, (FILE *stream, const char *prefix, unsigned long labelno),
252 default_internal_label)
253
254/* Output label for the constant. */
255DEFHOOK
256(declare_constant_name,
257 "A target hook to output to the stdio stream @var{file} any text necessary\n\
258for declaring the name @var{name} of a constant which is being defined. This\n\
259target hook is responsible for outputting the label definition (perhaps using\n\
260@code{assemble_label}). The argument @var{exp} is the value of the constant,\n\
261and @var{size} is the size of the constant in bytes. The @var{name}\n\
262will be an internal label.\n\
263\n\
264The default version of this target hook, define the @var{name} in the\n\
265usual manner as a label (by means of @code{assemble_label}).\n\
266\n\
267You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.",
268 void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
269 default_asm_declare_constant_name)
270
271/* Emit a ttype table reference to a typeinfo object. */
272DEFHOOK
273(ttype,
274 "This hook is used to output a reference from a frame unwinding table to\n\
275the type_info object identified by @var{sym}. It should return @code{true}\n\
276if the reference was output. Returning @code{false} will cause the\n\
277reference to be output using the normal Dwarf2 routines.",
278 bool, (rtx sym),
279 hook_bool_rtx_false)
280
281/* Emit an assembler directive to set visibility for the symbol
282 associated with the tree decl. */
283DEFHOOK
284(assemble_visibility,
285 "This target hook is a function to output to @var{asm_out_file} some\n\
286commands that will make the symbol(s) associated with @var{decl} have\n\
287hidden, protected or internal visibility as specified by @var{visibility}.",
288 void, (tree decl, int visibility),
289 default_assemble_visibility)
290
291DEFHOOK
292(print_patchable_function_entry,
293 "Generate a patchable area at the function start, consisting of\n\
294@var{patch_area_size} NOP instructions. If the target supports named\n\
295sections and if @var{record_p} is true, insert a pointer to the current\n\
296location in the table of patchable functions. The default implementation\n\
297of the hook places the table of pointers in the special section named\n\
298@code{__patchable_function_entries}.",
299 void, (FILE *file, unsigned HOST_WIDE_INT patch_area_size, bool record_p),
300 default_print_patchable_function_entry)
301
302/* Output the assembler code for entry to a function. */
303DEFHOOK
304(function_prologue,
305 "If defined, a function that outputs the assembler code for entry to a\n\
306function. The prologue is responsible for setting up the stack frame,\n\
307initializing the frame pointer register, saving registers that must be\n\
308saved, and allocating @var{size} additional bytes of storage for the\n\
309local variables. @var{file} is a stdio stream to which the assembler\n\
310code should be output.\n\
311\n\
312The label for the beginning of the function need not be output by this\n\
313macro. That has already been done when the macro is run.\n\
314\n\
315@findex regs_ever_live\n\
316To determine which registers to save, the macro can refer to the array\n\
317@code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
318@var{r} is used anywhere within the function. This implies the function\n\
319prologue should save register @var{r}, provided it is not one of the\n\
320call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
321@code{regs_ever_live}.)\n\
322\n\
323On machines that have ``register windows'', the function entry code does\n\
324not save on the stack the registers that are in the windows, even if\n\
325they are supposed to be preserved by function calls; instead it takes\n\
326appropriate steps to ``push'' the register stack, if any non-call-used\n\
327registers are used in the function.\n\
328\n\
329@findex frame_pointer_needed\n\
330On machines where functions may or may not have frame-pointers, the\n\
331function entry code must vary accordingly; it must set up the frame\n\
332pointer if one is wanted, and not otherwise. To determine whether a\n\
333frame pointer is in wanted, the macro can refer to the variable\n\
334@code{frame_pointer_needed}. The variable's value will be 1 at run\n\
335time in a function that needs a frame pointer. @xref{Elimination}.\n\
336\n\
337The function entry code is responsible for allocating any stack space\n\
338required for the function. This stack space consists of the regions\n\
339listed below. In most cases, these regions are allocated in the\n\
340order listed, with the last listed region closest to the top of the\n\
341stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
342the highest address if it is not defined). You can use a different order\n\
343for a machine if doing so is more convenient or required for\n\
344compatibility reasons. Except in cases where required by standard\n\
345or by a debugger, there is no reason why the stack layout used by GCC\n\
346need agree with that used by other compilers for a machine.",
347 void, (FILE *file),
348 default_function_pro_epilogue)
349
350/* Output the assembler code for end of prologue. */
351DEFHOOK
352(function_end_prologue,
353 "If defined, a function that outputs assembler code at the end of a\n\
354prologue. This should be used when the function prologue is being\n\
355emitted as RTL, and you have some extra assembler that needs to be\n\
356emitted. @xref{prologue instruction pattern}.",
357 void, (FILE *file),
358 no_asm_to_stream)
359
360/* Output the assembler code for start of epilogue. */
361DEFHOOK
362(function_begin_epilogue,
363 "If defined, a function that outputs assembler code at the start of an\n\
364epilogue. This should be used when the function epilogue is being\n\
365emitted as RTL, and you have some extra assembler that needs to be\n\
366emitted. @xref{epilogue instruction pattern}.",
367 void, (FILE *file),
368 no_asm_to_stream)
369
370/* Output the assembler code for function exit. */
371DEFHOOK
372(function_epilogue,
373 "If defined, a function that outputs the assembler code for exit from a\n\
374function. The epilogue is responsible for restoring the saved\n\
375registers and stack pointer to their values when the function was\n\
376called, and returning control to the caller. This macro takes the\n\
377same argument as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
378registers to restore are determined from @code{regs_ever_live} and\n\
379@code{CALL_USED_REGISTERS} in the same way.\n\
380\n\
381On some machines, there is a single instruction that does all the work\n\
382of returning from the function. On these machines, give that\n\
383instruction the name @samp{return} and do not define the macro\n\
384@code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
385\n\
386Do not define a pattern named @samp{return} if you want the\n\
387@code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target\n\
388switches to control whether return instructions or epilogues are used,\n\
389define a @samp{return} pattern with a validity condition that tests the\n\
390target switches appropriately. If the @samp{return} pattern's validity\n\
391condition is false, epilogues will be used.\n\
392\n\
393On machines where functions may or may not have frame-pointers, the\n\
394function exit code must vary accordingly. Sometimes the code for these\n\
395two cases is completely different. To determine whether a frame pointer\n\
396is wanted, the macro can refer to the variable\n\
397@code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
398a function that needs a frame pointer.\n\
399\n\
400Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
401@code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
402The C variable @code{current_function_is_leaf} is nonzero for such a\n\
403function. @xref{Leaf Functions}.\n\
404\n\
405On some machines, some functions pop their arguments on exit while\n\
406others leave that for the caller to do. For example, the 68020 when\n\
407given @option{-mrtd} pops arguments in functions that take a fixed\n\
408number of arguments.\n\
409\n\
410@findex pops_args\n\
411@findex crtl->args.pops_args\n\
412Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
413functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
414needs to know what was decided. The number of bytes of the current\n\
415function's arguments that this function should pop is available in\n\
416@code{crtl->args.pops_args}. @xref{Scalar Return}.",
417 void, (FILE *file),
418 default_function_pro_epilogue)
419
420/* Initialize target-specific sections. */
421DEFHOOK
422(init_sections,
423 "Define this hook if you need to do something special to set up the\n\
424@file{varasm.c} sections, or if your target has some special sections\n\
425of its own that you need to create.\n\
426\n\
427GCC calls this hook after processing the command line, but before writing\n\
428any assembly code, and before calling any of the section-returning hooks\n\
429described below.",
430 void, (void),
431 hook_void_void)
432
433/* Tell assembler to change to section NAME with attributes FLAGS.
434 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
435 which this section is associated. */
436DEFHOOK
437(named_section,
438 "Output assembly directives to switch to section @var{name}. The section\n\
439should have attributes as specified by @var{flags}, which is a bit mask\n\
440of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
441is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
442this section is associated.",
443 void, (const char *name, unsigned int flags, tree decl),
444 default_no_named_section)
445
446/* Tell assembler what section attributes to assign this elf section
447 declaration, using their numerical value. */
448DEFHOOK
449(elf_flags_numeric,
450 "This hook can be used to encode ELF section flags for which no letter\n\
451code has been defined in the assembler. It is called by\n\
452@code{default_asm_named_section} whenever the section flags need to be\n\
453emitted in the assembler output. If the hook returns true, then the\n\
454numerical value for ELF section flags should be calculated from\n\
455@var{flags} and saved in @var{*num}; the value is printed out instead of the\n\
456normal sequence of letter codes. If the hook is not defined, or if it\n\
457returns false, then @var{num} is ignored and the traditional letter sequence\n\
458is emitted.",
459 bool, (unsigned int flags, unsigned int *num),
460 hook_bool_uint_uintp_false)
461
462/* Return preferred text (sub)section for function DECL.
463 Main purpose of this function is to separate cold, normal and hot
464 functions. STARTUP is true when function is known to be used only
465 at startup (from static constructors or it is main()).
466 EXIT is true when function is known to be used only at exit
467 (from static destructors).
468 Return NULL if function should go to default text section. */
469DEFHOOK
470(function_section,
471 "Return preferred text (sub)section for function @var{decl}.\n\
472Main purpose of this function is to separate cold, normal and hot\n\
473functions. @var{startup} is true when function is known to be used only\n\
474at startup (from static constructors or it is @code{main()}).\n\
475@var{exit} is true when function is known to be used only at exit\n\
476(from static destructors).\n\
477Return NULL if function should go to default text section.",
478 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
479 default_function_section)
480
481/* Output the assembler code for function exit. */
482DEFHOOK
483(function_switched_text_sections,
484 "Used by the target to emit any assembler directives or additional\
485 labels needed when a function is partitioned between different\
486 sections. Output should be written to @var{file}. The function\
487 decl is available as @var{decl} and the new section is `cold' if\
488 @var{new_is_cold} is @code{true}.",
489 void, (FILE *file, tree decl, bool new_is_cold),
490 default_function_switched_text_sections)
491
492/* Return a mask describing how relocations should be treated when
493 selecting sections. Bit 1 should be set if global relocations
494 should be placed in a read-write section; bit 0 should be set if
495 local relocations should be placed in a read-write section. */
496DEFHOOK
497(reloc_rw_mask,
498 "Return a mask describing how relocations should be treated when\n\
499selecting sections. Bit 1 should be set if global relocations\n\
500should be placed in a read-write section; bit 0 should be set if\n\
501local relocations should be placed in a read-write section.\n\
502\n\
503The default version of this function returns 3 when @option{-fpic}\n\
504is in effect, and 0 otherwise. The hook is typically redefined\n\
505when the target cannot support (some kinds of) dynamic relocations\n\
506in read-only sections even in executables.",
507 int, (void),
508 default_reloc_rw_mask)
509
510 /* Return a section for EXP. It may be a DECL or a constant. RELOC
511 is nonzero if runtime relocations must be applied; bit 1 will be
512 set if the runtime relocations require non-local name resolution.
513 ALIGN is the required alignment of the data. */
514DEFHOOK
515(select_section,
516 "Return the section into which @var{exp} should be placed. You can\n\
517assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
518some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
519requires link-time relocations. Bit 0 is set when variable contains\n\
520local relocations only, while bit 1 is set for global relocations.\n\
521@var{align} is the constant alignment in bits.\n\
522\n\
523The default version of this function takes care of putting read-only\n\
524variables in @code{readonly_data_section}.\n\
525\n\
526See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
527 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
528 default_select_section)
529
530/* Return a section for X. MODE is X's mode and ALIGN is its
531 alignment in bits. */
532DEFHOOK
533(select_rtx_section,
534 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
535should be placed. You can assume that @var{x} is some kind of\n\
536constant in RTL@. The argument @var{mode} is redundant except in the\n\
537case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
538in bits.\n\
539\n\
540The default version of this function takes care of putting symbolic\n\
541constants in @code{flag_pic} mode in @code{data_section} and everything\n\
542else in @code{readonly_data_section}.",
543 section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
544 default_select_rtx_section)
545
546/* Select a unique section name for DECL. RELOC is the same as
547 for SELECT_SECTION. */
548DEFHOOK
549(unique_section,
550 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
551and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
552As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
553the initial value of @var{exp} requires link-time relocations.\n\
554\n\
555The default version of this function appends the symbol name to the\n\
556ELF section name that would normally be used for the symbol. For\n\
557example, the function @code{foo} would be placed in @code{.text.foo}.\n\
558Whatever the actual target object format, this is often good enough.",
559 void, (tree decl, int reloc),
560 default_unique_section)
561
562/* Return the readonly data section associated with function DECL. */
563DEFHOOK
564(function_rodata_section,
565 "Return the readonly data section associated with\n\
566@samp{DECL_SECTION_NAME (@var{decl})}.\n\
567The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
568the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
569if function is in @code{.text.name}, and the normal readonly-data section\n\
570otherwise.",
571 section *, (tree decl),
572 default_function_rodata_section)
573
574/* Nonnull if the target wants to override the default ".rodata" prefix
575 for mergeable data sections. */
576DEFHOOKPOD
577(mergeable_rodata_prefix,
578 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
579section names for mergeable constant data. Define this macro to override\n\
580the string if a different section name should be used.",
581 const char *, ".rodata")
582
583/* Return the section to be used for transactional memory clone tables. */
584DEFHOOK
585(tm_clone_table_section,
586 "Return the section that should be used for transactional memory clone\
587 tables.",
588 section *, (void), default_clone_table_section)
589
590/* Output a constructor for a symbol with a given priority. */
591DEFHOOK
592(constructor,
593 "If defined, a function that outputs assembler code to arrange to call\n\
594the function referenced by @var{symbol} at initialization time.\n\
595\n\
596Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
597no arguments and with no return value. If the target supports initialization\n\
598priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
599otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
600\n\
601If this macro is not defined by the target, a suitable default will\n\
602be chosen if (1) the target supports arbitrary section names, (2) the\n\
603target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
604is not defined.",
605 void, (rtx symbol, int priority), NULL)
606
607/* Output a destructor for a symbol with a given priority. */
608DEFHOOK
609(destructor,
610 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
611functions rather than initialization functions.",
612 void, (rtx symbol, int priority), NULL)
613
614/* Output the assembler code for a thunk function. THUNK_DECL is the
615 declaration for the thunk function itself, FUNCTION is the decl for
616 the target function. DELTA is an immediate constant offset to be
617 added to THIS. If VCALL_OFFSET is nonzero, the word at
618 *(*this + vcall_offset) should be added to THIS. */
619DEFHOOK
620(output_mi_thunk,
621 "A function that outputs the assembler code for a thunk\n\
622function, used to implement C++ virtual function calls with multiple\n\
623inheritance. The thunk acts as a wrapper around a virtual function,\n\
624adjusting the implicit object parameter before handing control off to\n\
625the real function.\n\
626\n\
627First, emit code to add the integer @var{delta} to the location that\n\
628contains the incoming first argument. Assume that this argument\n\
629contains a pointer, and is the one used to pass the @code{this} pointer\n\
630in C++. This is the incoming argument @emph{before} the function prologue,\n\
631e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
632all other incoming arguments.\n\
633\n\
634Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
635made after adding @code{delta}. In particular, if @var{p} is the\n\
636adjusted pointer, the following adjustment should be made:\n\
637\n\
638@smallexample\n\
639p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
640@end smallexample\n\
641\n\
642After the additions, emit code to jump to @var{function}, which is a\n\
643@code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
644not touch the return address. Hence returning from @var{FUNCTION} will\n\
645return to whoever called the current @samp{thunk}.\n\
646\n\
647The effect must be as if @var{function} had been called directly with\n\
648the adjusted first argument. This macro is responsible for emitting all\n\
649of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
650and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
651\n\
652The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
653have already been extracted from it.) It might possibly be useful on\n\
654some targets, but probably not.\n\
655\n\
656If you do not define this macro, the target-independent code in the C++\n\
657front end will generate a less efficient heavyweight thunk that calls\n\
658@var{function} instead of jumping to it. The generic approach does\n\
659not support varargs.",
660 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
661 HOST_WIDE_INT vcall_offset, tree function),
662 NULL)
663
664/* Determine whether output_mi_thunk would succeed. */
665/* ??? Ideally, this hook would not exist, and success or failure
666 would be returned from output_mi_thunk directly. But there's
667 too much undo-able setup involved in invoking output_mi_thunk.
668 Could be fixed by making output_mi_thunk emit rtl instead of
669 text to the output file. */
670DEFHOOK
671(can_output_mi_thunk,
672 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
673to output the assembler code for the thunk function specified by the\n\
674arguments it is passed, and false otherwise. In the latter case, the\n\
675generic approach will be used by the C++ front end, with the limitations\n\
676previously exposed.",
677 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
678 HOST_WIDE_INT vcall_offset, const_tree function),
679 hook_bool_const_tree_hwi_hwi_const_tree_false)
680
681/* Output any boilerplate text needed at the beginning of a
682 translation unit. */
683DEFHOOK
684(file_start,
685 "Output to @code{asm_out_file} any text which the assembler expects to\n\
686find at the beginning of a file. The default behavior is controlled\n\
687by two flags, documented below. Unless your target's assembler is\n\
688quite unusual, if you override the default, you should call\n\
689@code{default_file_start} at some point in your target hook. This\n\
690lets other target files rely on these variables.",
691 void, (void),
692 default_file_start)
693
694/* Output any boilerplate text needed at the end of a translation unit. */
695DEFHOOK
696(file_end,
697 "Output to @code{asm_out_file} any text which the assembler expects\n\
698to find at the end of a file. The default is to output nothing.",
699 void, (void),
700 hook_void_void)
701
702/* Output any boilerplate text needed at the beginning of an
703 LTO output stream. */
704DEFHOOK
705(lto_start,
706 "Output to @code{asm_out_file} any text which the assembler expects\n\
707to find at the start of an LTO section. The default is to output\n\
708nothing.",
709 void, (void),
710 hook_void_void)
711
712/* Output any boilerplate text needed at the end of an
713 LTO output stream. */
714DEFHOOK
715(lto_end,
716 "Output to @code{asm_out_file} any text which the assembler expects\n\
717to find at the end of an LTO section. The default is to output\n\
718nothing.",
719 void, (void),
720 hook_void_void)
721
722/* Output any boilerplace text needed at the end of a
723 translation unit before debug and unwind info is emitted. */
724DEFHOOK
725(code_end,
726 "Output to @code{asm_out_file} any text which is needed before emitting\n\
727unwind info and debug info at the end of a file. Some targets emit\n\
728here PIC setup thunks that cannot be emitted at the end of file,\n\
729because they couldn't have unwind info then. The default is to output\n\
730nothing.",
731 void, (void),
732 hook_void_void)
733
734/* Output an assembler pseudo-op to declare a library function name
735 external. */
736DEFHOOK
737(external_libcall,
738 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
739pseudo-op to declare a library function name external. The name of the\n\
740library function is given by @var{symref}, which is a @code{symbol_ref}.",
741 void, (rtx symref),
742 default_external_libcall)
743
744/* Output an assembler directive to mark decl live. This instructs
745 linker to not dead code strip this symbol. */
746DEFHOOK
747(mark_decl_preserved,
748 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
749directive to annotate @var{symbol} as used. The Darwin target uses the\n\
750.no_dead_code_strip directive.",
751 void, (const char *symbol),
752 hook_void_constcharptr)
753
754/* Output a record of the command line switches that have been passed. */
755DEFHOOK
756(record_gcc_switches,
757 "Provides the target with the ability to record the gcc command line\n\
758switches that have been passed to the compiler, and options that are\n\
759enabled. The @var{type} argument specifies what is being recorded.\n\
760It can take the following values:\n\
761\n\
762@table @gcctabopt\n\
763@item SWITCH_TYPE_PASSED\n\
764@var{text} is a command line switch that has been set by the user.\n\
765\n\
766@item SWITCH_TYPE_ENABLED\n\
767@var{text} is an option which has been enabled. This might be as a\n\
768direct result of a command line switch, or because it is enabled by\n\
769default or because it has been enabled as a side effect of a different\n\
770command line switch. For example, the @option{-O2} switch enables\n\
771various different individual optimization passes.\n\
772\n\
773@item SWITCH_TYPE_DESCRIPTIVE\n\
774@var{text} is either NULL or some descriptive text which should be\n\
775ignored. If @var{text} is NULL then it is being used to warn the\n\
776target hook that either recording is starting or ending. The first\n\
777time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
778warning is for start up and the second time the warning is for\n\
779wind down. This feature is to allow the target hook to make any\n\
780necessary preparations before it starts to record switches and to\n\
781perform any necessary tidying up after it has finished recording\n\
782switches.\n\
783\n\
784@item SWITCH_TYPE_LINE_START\n\
785This option can be ignored by this target hook.\n\
786\n\
787@item SWITCH_TYPE_LINE_END\n\
788This option can be ignored by this target hook.\n\
789@end table\n\
790\n\
791The hook's return value must be zero. Other return values may be\n\
792supported in the future.\n\
793\n\
794By default this hook is set to NULL, but an example implementation is\n\
795provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
796it records the switches as ASCII text inside a new, string mergeable\n\
797section in the assembler output file. The name of the new section is\n\
798provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
799hook.",
800 int, (print_switch_type type, const char *text),
801 NULL)
802
803/* The name of the section that the example ELF implementation of
804 record_gcc_switches will use to store the information. Target
805 specific versions of record_gcc_switches may or may not use
806 this information. */
807DEFHOOKPOD
808(record_gcc_switches_section,
809 "This is the name of the section that will be created by the example\n\
810ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
811hook.",
812 const char *, ".GCC.command.line")
813
814/* Output the definition of a section anchor. */
815DEFHOOK
816(output_anchor,
817 "Write the assembly code to define section anchor @var{x}, which is a\n\
818@code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
819The hook is called with the assembly output position set to the beginning\n\
820of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
821\n\
822If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
823it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
824If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
825is @code{NULL}, which disables the use of section anchors altogether.",
826 void, (rtx x),
827 default_asm_output_anchor)
828
829DEFHOOK
830(output_ident,
831 "Output a string based on @var{name}, suitable for the @samp{#ident} \
832 directive, or the equivalent directive or pragma in non-C-family languages. \
833 If this hook is not defined, nothing is output for the @samp{#ident} \
834 directive.",
835 void, (const char *name),
836 hook_void_constcharptr)
837
838/* Output a DTP-relative reference to a TLS symbol. */
839DEFHOOK
840(output_dwarf_dtprel,
841 "If defined, this target hook is a function which outputs a DTP-relative\n\
842reference to the given TLS symbol of the specified size.",
843 void, (FILE *file, int size, rtx x),
844 NULL)
845
846/* Some target machines need to postscan each insn after it is output. */
847DEFHOOK
848(final_postscan_insn,
849 "If defined, this target hook is a function which is executed just after the\n\
850output of assembler code for @var{insn}, to change the mode of the assembler\n\
851if necessary.\n\
852\n\
853Here the argument @var{opvec} is the vector containing the operands\n\
854extracted from @var{insn}, and @var{noperands} is the number of\n\
855elements of the vector which contain meaningful data for this insn.\n\
856The contents of this vector are what was used to convert the insn\n\
857template into assembler code, so you can change the assembler mode\n\
858by checking the contents of the vector.",
859 void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
860 NULL)
861
862/* Emit the trampoline template. This hook may be NULL. */
863DEFHOOK
864(trampoline_template,
865 "This hook is called by @code{assemble_trampoline_template} to output,\n\
866on the stream @var{f}, assembler code for a block of data that contains\n\
867the constant parts of a trampoline. This code should not include a\n\
868label---the label is taken care of automatically.\n\
869\n\
870If you do not define this hook, it means no template is needed\n\
871for the target. Do not define this hook on systems where the block move\n\
872code to copy the trampoline into place would be larger than the code\n\
873to generate it on the spot.",
874 void, (FILE *f),
875 NULL)
876
877DEFHOOK
878(output_source_filename,
879 "Output DWARF debugging information which indicates that filename\
880 @var{name} is the current source file to the stdio stream @var{file}.\n\
881 \n\
882 This target hook need not be defined if the standard form of output\
883 for the file format in use is appropriate.",
884 void ,(FILE *file, const char *name),
885 default_asm_output_source_filename)
886
887DEFHOOK
888(output_addr_const_extra,
889 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
890can't deal with, and output assembly code to @var{file} corresponding to\n\
891the pattern @var{x}. This may be used to allow machine-dependent\n\
892@code{UNSPEC}s to appear within constants.\n\
893\n\
894If target hook fails to recognize a pattern, it must return @code{false},\n\
895so that a standard error message is printed. If it prints an error message\n\
896itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
897return @code{true}.",
898 bool, (FILE *file, rtx x),
899 hook_bool_FILEptr_rtx_false)
900
901/* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
902 even though that is not reflected in the macro name to override their
903 initializers. */
904#undef HOOK_PREFIX
905#define HOOK_PREFIX "TARGET_"
906
907/* Emit a machine-specific insn operand. */
908/* ??? tm.texi only documents the old macro PRINT_OPERAND,
909 not this hook, and uses a different name for the argument FILE. */
910DEFHOOK_UNDOC
911(print_operand,
912 "",
913 void, (FILE *file, rtx x, int code),
914 default_print_operand)
915
916/* Emit a machine-specific memory address. */
917/* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
918 not this hook, and uses different argument names. */
919DEFHOOK_UNDOC
920(print_operand_address,
921 "",
922 void, (FILE *file, machine_mode mode, rtx addr),
923 default_print_operand_address)
924
925/* Determine whether CODE is a valid punctuation character for the
926 `print_operand' hook. */
927/* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
928 not this hook. */
929DEFHOOK_UNDOC
930(print_operand_punct_valid_p,
931 "",
932 bool ,(unsigned char code),
933 default_print_operand_punct_valid_p)
934
935/* Given a symbol name, perform same mangling as assemble_name and
936 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
937DEFHOOK
938(mangle_assembler_name,
939 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
940 @code{assemble_name}, but in memory rather than to a file stream, returning\
941 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\
942 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
943 then prepends the @code{USER_LABEL_PREFIX}, if any.",
944 tree, (const char *name),
945 default_mangle_assembler_name)
946
947HOOK_VECTOR_END (asm_out)
948
949/* Functions relating to instruction scheduling. All of these
950 default to null pointers, which haifa-sched.c looks for and handles. */
951#undef HOOK_PREFIX
952#define HOOK_PREFIX "TARGET_SCHED_"
953HOOK_VECTOR (TARGET_SCHED, sched)
954
955/* Given the current cost, COST, of an insn, INSN, calculate and
956 return a new cost based on its relationship to DEP_INSN through
957 the dependence LINK. The default is to make no adjustment. */
958DEFHOOK
959(adjust_cost,
960 "This function corrects the value of @var{cost} based on the\n\
961relationship between @var{insn} and @var{dep_insn} through a\n\
962dependence of type dep_type, and strength @var{dw}. It should return the new\n\
963value. The default is to make no adjustment to @var{cost}. This can be\n\
964used for example to specify to the scheduler using the traditional pipeline\n\
965description that an output- or anti-dependence does not incur the same cost\n\
966as a data-dependence. If the scheduler using the automaton based pipeline\n\
967description, the cost of anti-dependence is zero and the cost of\n\
968output-dependence is maximum of one and the difference of latency\n\
969times of the first and the second insns. If these values are not\n\
970acceptable, you could use the hook to modify them too. See also\n\
971@pxref{Processor pipeline description}.",
972 int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
973 unsigned int dw),
974 NULL)
975
976/* Adjust the priority of an insn as you see fit. Returns the new priority. */
977DEFHOOK
978(adjust_priority,
979 "This hook adjusts the integer scheduling priority @var{priority} of\n\
980@var{insn}. It should return the new priority. Increase the priority to\n\
981execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
982later. Do not define this hook if you do not need to adjust the\n\
983scheduling priorities of insns.",
984 int, (rtx_insn *insn, int priority), NULL)
985
986/* Function which returns the maximum number of insns that can be
987 scheduled in the same machine cycle. This must be constant
988 over an entire compilation. The default is 1. */
989DEFHOOK
990(issue_rate,
991 "This hook returns the maximum number of instructions that can ever\n\
992issue at the same time on the target machine. The default is one.\n\
993Although the insn scheduler can define itself the possibility of issue\n\
994an insn on the same cycle, the value can serve as an additional\n\
995constraint to issue insns on the same simulated processor cycle (see\n\
996hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
997This value must be constant over the entire compilation. If you need\n\
998it to vary depending on what the instructions are, you must use\n\
999@samp{TARGET_SCHED_VARIABLE_ISSUE}.",
1000 int, (void), NULL)
1001
1002/* Calculate how much this insn affects how many more insns we
1003 can emit this cycle. Default is they all cost the same. */
1004DEFHOOK
1005(variable_issue,
1006 "This hook is executed by the scheduler after it has scheduled an insn\n\
1007from the ready list. It should return the number of insns which can\n\
1008still be issued in the current cycle. The default is\n\
1009@samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
1010@code{USE}, which normally are not counted against the issue rate.\n\
1011You should define this hook if some insns take more machine resources\n\
1012than others, so that fewer insns can follow them in the same cycle.\n\
1013@var{file} is either a null pointer, or a stdio stream to write any\n\
1014debug output to. @var{verbose} is the verbose level provided by\n\
1015@option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
1016was scheduled.",
1017 int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
1018
1019/* Initialize machine-dependent scheduling code. */
1020DEFHOOK
1021(init,
1022 "This hook is executed by the scheduler at the beginning of each block of\n\
1023instructions that are to be scheduled. @var{file} is either a null\n\
1024pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
1025is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1026@var{max_ready} is the maximum number of insns in the current scheduling\n\
1027region that can be live at the same time. This can be used to allocate\n\
1028scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1029 void, (FILE *file, int verbose, int max_ready), NULL)
1030
1031/* Finalize machine-dependent scheduling code. */
1032DEFHOOK
1033(finish,
1034 "This hook is executed by the scheduler at the end of each block of\n\
1035instructions that are to be scheduled. It can be used to perform\n\
1036cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1037is either a null pointer, or a stdio stream to write any debug output\n\
1038to. @var{verbose} is the verbose level provided by\n\
1039@option{-fsched-verbose-@var{n}}.",
1040 void, (FILE *file, int verbose), NULL)
1041
1042 /* Initialize machine-dependent function wide scheduling code. */
1043DEFHOOK
1044(init_global,
1045 "This hook is executed by the scheduler after function level initializations.\n\
1046@var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1047@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1048@var{old_max_uid} is the maximum insn uid when scheduling begins.",
1049 void, (FILE *file, int verbose, int old_max_uid), NULL)
1050
1051/* Finalize machine-dependent function wide scheduling code. */
1052DEFHOOK
1053(finish_global,
1054 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1055@var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1056@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1057 void, (FILE *file, int verbose), NULL)
1058
1059/* Reorder insns in a machine-dependent fashion, in two different
1060 places. Default does nothing. */
1061DEFHOOK
1062(reorder,
1063 "This hook is executed by the scheduler after it has scheduled the ready\n\
1064list, to allow the machine description to reorder it (for example to\n\
1065combine two small instructions together on @samp{VLIW} machines).\n\
1066@var{file} is either a null pointer, or a stdio stream to write any\n\
1067debug output to. @var{verbose} is the verbose level provided by\n\
1068@option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1069list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1070a pointer to the number of elements in the ready list. The scheduler\n\
1071reads the ready list in reverse order, starting with\n\
1072@var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1073is the timer tick of the scheduler. You may modify the ready list and\n\
1074the number of ready insns. The return value is the number of insns that\n\
1075can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1076@samp{TARGET_SCHED_REORDER2}.",
1077 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1078
1079DEFHOOK
1080(reorder2,
1081 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1082function is called whenever the scheduler starts a new cycle. This one\n\
1083is called once per iteration over a cycle, immediately after\n\
1084@samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1085return the number of insns to be scheduled in the same cycle. Defining\n\
1086this hook can be useful if there are frequent situations where\n\
1087scheduling one insn causes other insns to become ready in the same\n\
1088cycle. These other insns can then be taken into account properly.",
1089 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1090
1091DEFHOOK
1092(macro_fusion_p,
1093 "This hook is used to check whether target platform supports macro fusion.",
1094 bool, (void), NULL)
1095
1096DEFHOOK
1097(macro_fusion_pair_p,
1098 "This hook is used to check whether two insns should be macro fused for\n\
1099a target microarchitecture. If this hook returns true for the given insn pair\n\
1100(@var{prev} and @var{curr}), the scheduler will put them into a sched\n\
1101group, and they will not be scheduled apart. The two insns will be either\n\
1102two SET insns or a compare and a conditional jump and this hook should\n\
1103validate any dependencies needed to fuse the two insns together.",
1104 bool, (rtx_insn *prev, rtx_insn *curr), NULL)
1105
1106/* The following member value is a pointer to a function called
1107 after evaluation forward dependencies of insns in chain given
1108 by two parameter values (head and tail correspondingly). */
1109DEFHOOK
1110(dependencies_evaluation_hook,
1111 "This hook is called after evaluation forward dependencies of insns in\n\
1112chain given by two parameter values (@var{head} and @var{tail}\n\
1113correspondingly) but before insns scheduling of the insn chain. For\n\
1114example, it can be used for better insn classification if it requires\n\
1115analysis of dependencies. This hook can use backward and forward\n\
1116dependencies of the insn scheduler because they are already\n\
1117calculated.",
1118 void, (rtx_insn *head, rtx_insn *tail), NULL)
1119
1120/* The values of the following four members are pointers to functions
1121 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1122 dfa_post_cycle_insn give functions returning insns which are used to
1123 change the pipeline hazard recognizer state when the new simulated
1124 processor cycle correspondingly starts and finishes. The function
1125 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1126 used to initialize the corresponding insns. The default values of
1127 the members result in not changing the automaton state when the
1128 new simulated processor cycle correspondingly starts and finishes. */
1129
1130DEFHOOK
1131(init_dfa_pre_cycle_insn,
1132 "The hook can be used to initialize data used by the previous hook.",
1133 void, (void), NULL)
1134
1135DEFHOOK
1136(dfa_pre_cycle_insn,
1137 "The hook returns an RTL insn. The automaton state used in the\n\
1138pipeline hazard recognizer is changed as if the insn were scheduled\n\
1139when the new simulated processor cycle starts. Usage of the hook may\n\
1140simplify the automaton pipeline description for some @acronym{VLIW}\n\
1141processors. If the hook is defined, it is used only for the automaton\n\
1142based pipeline description. The default is not to change the state\n\
1143when the new simulated processor cycle starts.",
1144 rtx, (void), NULL)
1145
1146DEFHOOK
1147(init_dfa_post_cycle_insn,
1148 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1149used to initialize data used by the previous hook.",
1150 void, (void), NULL)
1151
1152DEFHOOK
1153(dfa_post_cycle_insn,
1154 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1155to changed the state as if the insn were scheduled when the new\n\
1156simulated processor cycle finishes.",
1157 rtx_insn *, (void), NULL)
1158
1159/* The values of the following two members are pointers to
1160 functions used to simplify the automaton descriptions.
1161 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1162 immediately before and after cycle is advanced. */
1163
1164DEFHOOK
1165(dfa_pre_advance_cycle,
1166 "The hook to notify target that the current simulated cycle is about to finish.\n\
1167The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1168to change the state in more complicated situations - e.g., when advancing\n\
1169state on a single insn is not enough.",
1170 void, (void), NULL)
1171
1172DEFHOOK
1173(dfa_post_advance_cycle,
1174 "The hook to notify target that new simulated cycle has just started.\n\
1175The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1176to change the state in more complicated situations - e.g., when advancing\n\
1177state on a single insn is not enough.",
1178 void, (void), NULL)
1179
1180/* The following member value is a pointer to a function returning value
1181 which defines how many insns in queue `ready' will we try for
1182 multi-pass scheduling. If the member value is nonzero and the
1183 function returns positive value, the DFA based scheduler will make
1184 multi-pass scheduling for the first cycle. In other words, we will
1185 try to choose ready insn which permits to start maximum number of
1186 insns on the same cycle. */
1187DEFHOOK
1188(first_cycle_multipass_dfa_lookahead,
1189 "This hook controls better choosing an insn from the ready insn queue\n\
1190for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1191chooses the first insn from the queue. If the hook returns a positive\n\
1192value, an additional scheduler code tries all permutations of\n\
1193@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1194subsequent ready insns to choose an insn whose issue will result in\n\
1195maximal number of issued insns on the same cycle. For the\n\
1196@acronym{VLIW} processor, the code could actually solve the problem of\n\
1197packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1198rules of @acronym{VLIW} packing are described in the automaton.\n\
1199\n\
1200This code also could be used for superscalar @acronym{RISC}\n\
1201processors. Let us consider a superscalar @acronym{RISC} processor\n\
1202with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1203@var{B}, some insns can be executed only in pipelines @var{B} or\n\
1204@var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1205processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1206@var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1207until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1208the processor could issue all 3 insns per cycle.\n\
1209\n\
1210Actually this code demonstrates advantages of the automaton based\n\
1211pipeline hazard recognizer. We try quickly and easy many insn\n\
1212schedules to choose the best one.\n\
1213\n\
1214The default is no multipass scheduling.",
1215 int, (void), NULL)
1216
1217/* The following member value is pointer to a function controlling
1218 what insns from the ready insn queue will be considered for the
1219 multipass insn scheduling. If the hook returns zero for insn
1220 passed as the parameter, the insn will be not chosen to be issued. */
1221DEFHOOK
1222(first_cycle_multipass_dfa_lookahead_guard,
1223 "\n\
1224This hook controls what insns from the ready insn queue will be\n\
1225considered for the multipass insn scheduling. If the hook returns\n\
1226zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1227Positive return values will remove @var{insn} from consideration on\n\
1228the current round of multipass scheduling.\n\
1229Negative return values will remove @var{insn} from consideration for given\n\
1230number of cycles.\n\
1231Backends should be careful about returning non-zero for highest priority\n\
1232instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1233to allow backends make correct judgements.\n\
1234\n\
1235The default is that any ready insns can be chosen to be issued.",
1236 int, (rtx_insn *insn, int ready_index), NULL)
1237
1238/* This hook prepares the target for a new round of multipass
1239 scheduling.
1240 DATA is a pointer to target-specific data used for multipass scheduling.
1241 READY_TRY and N_READY represent the current state of search in the
1242 optimization space. The target can filter out instructions that
1243 should not be tried during current round by setting corresponding
1244 elements in READY_TRY to non-zero.
1245 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1246 scheduling on current cycle. */
1247DEFHOOK
1248(first_cycle_multipass_begin,
1249 "This hook prepares the target backend for a new round of multipass\n\
1250scheduling.",
1251 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1252 NULL)
1253
1254/* This hook is called when multipass scheduling evaluates instruction INSN.
1255 DATA is a pointer to target-specific data that can be used to record effects
1256 of INSN on CPU that are not 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 INSN is the instruction being evaluated.
1262 PREV_DATA is a pointer to target-specific data corresponding
1263 to a state before issuing INSN. */
1264DEFHOOK
1265(first_cycle_multipass_issue,
1266 "This hook is called when multipass scheduling evaluates instruction INSN.",
1267 void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1268 const void *prev_data), NULL)
1269
1270/* This hook is called when multipass scheduling backtracks from evaluation of
1271 instruction corresponding to DATA.
1272 DATA is a pointer to target-specific data that stores the effects
1273 of instruction from which the algorithm backtracks on CPU that are not
1274 described in DFA.
1275 READY_TRY and N_READY represent the current state of search in the
1276 optimization space. The target can filter out instructions that
1277 should not be tried after issuing INSN by setting corresponding
1278 elements in READY_TRY to non-zero. */
1279DEFHOOK
1280(first_cycle_multipass_backtrack,
1281 "This is called when multipass scheduling backtracks from evaluation of\n\
1282an instruction.",
1283 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1284
1285/* This hook notifies the target about the result of the concluded current
1286 round of multipass scheduling.
1287 DATA is a pointer.
1288 If DATA is non-NULL it points to target-specific data used for multipass
1289 scheduling which corresponds to instruction at the start of the chain of
1290 the winning solution. DATA is NULL when multipass scheduling cannot find
1291 a good enough solution on current cycle and decides to retry later,
1292 usually after advancing the cycle count. */
1293DEFHOOK
1294(first_cycle_multipass_end,
1295 "This hook notifies the target about the result of the concluded current\n\
1296round of multipass scheduling.",
1297 void, (const void *data), NULL)
1298
1299/* This hook is called to initialize target-specific data for multipass
1300 scheduling after it has been allocated.
1301 DATA is a pointer to target-specific data that stores the effects
1302 of instruction from which the algorithm backtracks on CPU that are not
1303 described in DFA. */
1304DEFHOOK
1305(first_cycle_multipass_init,
1306 "This hook initializes target-specific data used in multipass scheduling.",
1307 void, (void *data), NULL)
1308
1309/* This hook is called to finalize target-specific data for multipass
1310 scheduling before it is deallocated.
1311 DATA is a pointer to target-specific data that stores the effects
1312 of instruction from which the algorithm backtracks on CPU that are not
1313 described in DFA. */
1314DEFHOOK
1315(first_cycle_multipass_fini,
1316 "This hook finalizes target-specific data used in multipass scheduling.",
1317 void, (void *data), NULL)
1318
1319/* The following member value is pointer to a function called by
1320 the insn scheduler before issuing insn passed as the third
1321 parameter on given cycle. If the hook returns nonzero, the
1322 insn is not issued on given processors cycle. Instead of that,
1323 the processor cycle is advanced. If the value passed through
1324 the last parameter is zero, the insn ready queue is not sorted
1325 on the new cycle start as usually. The first parameter passes
1326 file for debugging output. The second one passes the scheduler
1327 verbose level of the debugging output. The forth and the fifth
1328 parameter values are correspondingly processor cycle on which
1329 the previous insn has been issued and the current processor cycle. */
1330DEFHOOK
1331(dfa_new_cycle,
1332 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1333on cycle @var{clock}. If the hook returns nonzero,\n\
1334@var{insn} is not issued on this processor cycle. Instead,\n\
1335the processor cycle is advanced. If *@var{sort_p}\n\
1336is zero, the insn ready queue is not sorted on the new cycle\n\
1337start as usually. @var{dump} and @var{verbose} specify the file and\n\
1338verbosity level to use for debugging output.\n\
1339@var{last_clock} and @var{clock} are, respectively, the\n\
1340processor cycle on which the previous insn has been issued,\n\
1341and the current processor cycle.",
1342 int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1343 int clock, int *sort_p),
1344 NULL)
1345
1346/* The following member value is a pointer to a function called by the
1347 insn scheduler. It should return true if there exists a dependence
1348 which is considered costly by the target, between the insn
1349 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1350 the dep that represents the dependence between the two insns. The
1351 second argument is the cost of the dependence as estimated by
1352 the scheduler. The last argument is the distance in cycles
1353 between the already scheduled insn (first parameter) and the
1354 second insn (second parameter). */
1355DEFHOOK
1356(is_costly_dependence,
1357 "This hook is used to define which dependences are considered costly by\n\
1358the target, so costly that it is not advisable to schedule the insns that\n\
1359are involved in the dependence too close to one another. The parameters\n\
1360to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1361being evaluated. The second parameter @var{cost} is the cost of the\n\
1362dependence as estimated by the scheduler, and the third\n\
1363parameter @var{distance} is the distance in cycles between the two insns.\n\
1364The hook returns @code{true} if considering the distance between the two\n\
1365insns the dependence between them is considered costly by the target,\n\
1366and @code{false} otherwise.\n\
1367\n\
1368Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1369where (a) it's practically hopeless to predict the actual data/resource\n\
1370delays, however: (b) there's a better chance to predict the actual grouping\n\
1371that will be formed, and (c) correctly emulating the grouping can be very\n\
1372important. In such targets one may want to allow issuing dependent insns\n\
1373closer to one another---i.e., closer than the dependence distance; however,\n\
1374not in cases of ``costly dependences'', which this hooks allows to define.",
1375 bool, (struct _dep *_dep, int cost, int distance), NULL)
1376
1377/* The following member value is a pointer to a function called
1378 by the insn scheduler. This hook is called to notify the backend
1379 that new instructions were emitted. */
1380DEFHOOK
1381(h_i_d_extended,
1382 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1383the instruction stream. The hook notifies a target backend to extend its\n\
1384per instruction data structures.",
1385 void, (void), NULL)
1386
1387/* Next 5 functions are for multi-point scheduling. */
1388
1389/* Allocate memory for scheduler context. */
1390DEFHOOK
1391(alloc_sched_context,
1392 "Return a pointer to a store large enough to hold target scheduling context.",
1393 void *, (void), NULL)
1394
1395/* Fills the context from the local machine scheduler context. */
1396DEFHOOK
1397(init_sched_context,
1398 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1399It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1400beginning of the block. Otherwise, copy the current context into @var{tc}.",
1401 void, (void *tc, bool clean_p), NULL)
1402
1403/* Sets local machine scheduler context to a saved value. */
1404DEFHOOK
1405(set_sched_context,
1406 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1407 void, (void *tc), NULL)
1408
1409/* Clears a scheduler context so it becomes like after init. */
1410DEFHOOK
1411(clear_sched_context,
1412 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1413 void, (void *tc), NULL)
1414
1415/* Frees the scheduler context. */
1416DEFHOOK
1417(free_sched_context,
1418 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1419 void, (void *tc), NULL)
1420
1421/* The following member value is a pointer to a function called
1422 by the insn scheduler.
1423 The first parameter is an instruction, the second parameter is the type
1424 of the requested speculation, and the third parameter is a pointer to the
1425 speculative pattern of the corresponding type (set if return value == 1).
1426 It should return
1427 -1, if there is no pattern, that will satisfy the requested speculation type,
1428 0, if current pattern satisfies the requested speculation type,
1429 1, if pattern of the instruction should be changed to the newly
1430 generated one. */
1431DEFHOOK
1432(speculate_insn,
1433 "This hook is called by the insn scheduler when @var{insn} has only\n\
1434speculative dependencies and therefore can be scheduled speculatively.\n\
1435The hook is used to check if the pattern of @var{insn} has a speculative\n\
1436version and, in case of successful check, to generate that speculative\n\
1437pattern. The hook should return 1, if the instruction has a speculative form,\n\
1438or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1439speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1440the generated speculative pattern.",
1441 int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1442
1443/* The following member value is a pointer to a function called
1444 by the insn scheduler. It should return true if the check instruction
1445 passed as the parameter needs a recovery block. */
1446DEFHOOK
1447(needs_block_p,
1448 "This hook is called by the insn scheduler during generation of recovery code\n\
1449for @var{insn}. It should return @code{true}, if the corresponding check\n\
1450instruction should branch to recovery code, or @code{false} otherwise.",
1451 bool, (unsigned int dep_status), NULL)
1452
1453/* The following member value is a pointer to a function called
1454 by the insn scheduler. It should return a pattern for the check
1455 instruction.
1456 The first parameter is a speculative instruction, the second parameter
1457 is the label of the corresponding recovery block (or null, if it is a
1458 simple check). The third parameter is the kind of speculation that
1459 is being performed. */
1460DEFHOOK
1461(gen_spec_check,
1462 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1463check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1464speculative instruction for which the check should be generated.\n\
1465@var{label} is either a label of a basic block, where recovery code should\n\
1466be emitted, or a null pointer, when requested check doesn't branch to\n\
1467recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1468a pattern for a branchy check corresponding to a simple check denoted by\n\
1469@var{insn} should be generated. In this case @var{label} can't be null.",
1470 rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1471
1472/* The following member value is a pointer to a function that provides
1473 information about the speculation capabilities of the target.
1474 The parameter is a pointer to spec_info variable. */
1475DEFHOOK
1476(set_sched_flags,
1477 "This hook is used by the insn scheduler to find out what features should be\n\
1478enabled/used.\n\
1479The structure *@var{spec_info} should be filled in by the target.\n\
1480The structure describes speculation types that can be used in the scheduler.",
1481 void, (struct spec_info_def *spec_info), NULL)
1482
1483DEFHOOK_UNDOC
1484(get_insn_spec_ds,
1485 "Return speculation types of instruction @var{insn}.",
1486 unsigned int, (rtx_insn *insn), NULL)
1487
1488DEFHOOK_UNDOC
1489(get_insn_checked_ds,
1490 "Return speculation types that are checked for instruction @var{insn}",
1491 unsigned int, (rtx_insn *insn), NULL)
1492
1493DEFHOOK
1494(can_speculate_insn,
1495 "Some instructions should never be speculated by the schedulers, usually\n\
1496 because the instruction is too expensive to get this wrong. Often such\n\
1497 instructions have long latency, and often they are not fully modeled in the\n\
1498 pipeline descriptions. This hook should return @code{false} if @var{insn}\n\
1499 should not be speculated.",
1500 bool, (rtx_insn *insn), hook_bool_rtx_insn_true)
1501
1502DEFHOOK_UNDOC
1503(skip_rtx_p,
1504 "Return bool if rtx scanning should just skip current layer and\
1505 advance to the inner rtxes.",
1506 bool, (const_rtx x), NULL)
1507
1508/* The following member value is a pointer to a function that provides
1509 information about the target resource-based lower bound which is
1510 used by the swing modulo scheduler. The parameter is a pointer
1511 to ddg variable. */
1512DEFHOOK
1513(sms_res_mii,
1514 "This hook is called by the swing modulo scheduler to calculate a\n\
1515resource-based lower bound which is based on the resources available in\n\
1516the machine and the resources required by each instruction. The target\n\
1517backend can use @var{g} to calculate such bound. A very simple lower\n\
1518bound will be used in case this hook is not implemented: the total number\n\
1519of instructions divided by the issue rate.",
1520 int, (struct ddg *g), NULL)
1521
1522/* The following member value is a function that initializes dispatch
1523 schedling and adds instructions to dispatch window according to its
1524 parameters. */
1525DEFHOOK
1526(dispatch_do,
1527"This hook is called by Haifa Scheduler. It performs the operation specified\n\
1528in its second parameter.",
1529void, (rtx_insn *insn, int x),
1530hook_void_rtx_insn_int)
1531
1532/* The following member value is a a function that returns true is
1533 dispatch schedling is supported in hardware and condition passed
1534 as the second parameter is true. */
1535DEFHOOK
1536(dispatch,
1537"This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1538is supported in hardware and the condition specified in the parameter is true.",
1539bool, (rtx_insn *insn, int x),
1540hook_bool_rtx_insn_int_false)
1541
1542DEFHOOKPOD
1543(exposed_pipeline,
1544"True if the processor has an exposed pipeline, which means that not just\n\
1545the order of instructions is important for correctness when scheduling, but\n\
1546also the latencies of operations.",
1547bool, false)
1548
1549/* The following member value is a function that returns number
1550 of operations reassociator should try to put in parallel for
1551 statements of the given type. By default 1 is used. */
1552DEFHOOK
1553(reassociation_width,
1554"This hook is called by tree reassociator to determine a level of\n\
1555parallelism required in output calculations chain.",
1556int, (unsigned int opc, machine_mode mode),
1557hook_int_uint_mode_1)
1558
1559/* The following member value is a function that returns priority for
1560 fusion of each instruction via pointer parameters. */
1561DEFHOOK
1562(fusion_priority,
1563"This hook is called by scheduling fusion pass. It calculates fusion\n\
1564priorities for each instruction passed in by parameter. The priorities\n\
1565are returned via pointer parameters.\n\
1566\n\
1567@var{insn} is the instruction whose priorities need to be calculated.\n\
1568@var{max_pri} is the maximum priority can be returned in any cases.\n\
1569@var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1570fusion priority should be calculated and returned.\n\
1571@var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1572should be calculated and returned.\n\
1573\n\
1574Same @var{fusion_pri} should be returned for instructions which should\n\
1575be scheduled together. Different @var{pri} should be returned for\n\
1576instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1577sort key, @var{pri} is the minor sort key. All instructions will be\n\
1578scheduled according to the two priorities. All priorities calculated\n\
1579should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1580false dependencies, @var{fusion_pri} of instructions which need to be\n\
1581scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1582instructions.\n\
1583\n\
1584Given below example:\n\
1585\n\
1586@smallexample\n\
1587 ldr r10, [r1, 4]\n\
1588 add r4, r4, r10\n\
1589 ldr r15, [r2, 8]\n\
1590 sub r5, r5, r15\n\
1591 ldr r11, [r1, 0]\n\
1592 add r4, r4, r11\n\
1593 ldr r16, [r2, 12]\n\
1594 sub r5, r5, r16\n\
1595@end smallexample\n\
1596\n\
1597On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1598merged. Since peephole2 pass can't help in this case unless consecutive\n\
1599loads are actually next to each other in instruction flow. That's where\n\
1600this scheduling fusion pass works. This hook calculates priority for each\n\
1601instruction based on its fustion type, like:\n\
1602\n\
1603@smallexample\n\
1604 ldr r10, [r1, 4] ; fusion_pri=99, pri=96\n\
1605 add r4, r4, r10 ; fusion_pri=100, pri=100\n\
1606 ldr r15, [r2, 8] ; fusion_pri=98, pri=92\n\
1607 sub r5, r5, r15 ; fusion_pri=100, pri=100\n\
1608 ldr r11, [r1, 0] ; fusion_pri=99, pri=100\n\
1609 add r4, r4, r11 ; fusion_pri=100, pri=100\n\
1610 ldr r16, [r2, 12] ; fusion_pri=98, pri=88\n\
1611 sub r5, r5, r16 ; fusion_pri=100, pri=100\n\
1612@end smallexample\n\
1613\n\
1614Scheduling fusion pass then sorts all ready to issue instructions according\n\
1615to the priorities. As a result, instructions of same fusion type will be\n\
1616pushed together in instruction flow, like:\n\
1617\n\
1618@smallexample\n\
1619 ldr r11, [r1, 0]\n\
1620 ldr r10, [r1, 4]\n\
1621 ldr r15, [r2, 8]\n\
1622 ldr r16, [r2, 12]\n\
1623 add r4, r4, r10\n\
1624 sub r5, r5, r15\n\
1625 add r4, r4, r11\n\
1626 sub r5, r5, r16\n\
1627@end smallexample\n\
1628\n\
1629Now peephole2 pass can simply merge the two pairs of loads.\n\
1630\n\
1631Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1632work, it is only enabled by default when peephole2 is in effect.\n\
1633\n\
1634This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1635the hook implementation for how different fusion types are supported.",
1636void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1637
1638HOOK_VECTOR_END (sched)
1639
1640/* Functions relating to OpenMP SIMD and __attribute__((simd)) clones. */
1641#undef HOOK_PREFIX
1642#define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1643HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1644
1645DEFHOOK
1646(compute_vecsize_and_simdlen,
1647"This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1648fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1649@var{simdlen} field if it was previously 0.\n\
1650The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1651or number of @var{vecsize_mangle} variants that should be emitted.",
1652int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1653
1654DEFHOOK
1655(adjust,
1656"This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1657to SIMD clone @var{node} if needed.",
1658void, (struct cgraph_node *), NULL)
1659
1660DEFHOOK
1661(usable,
1662"This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1663in vectorized loops in current function, or non-negative number if it is\n\
1664usable. In that case, the smaller the number is, the more desirable it is\n\
1665to use it.",
1666int, (struct cgraph_node *), NULL)
1667
1668HOOK_VECTOR_END (simd_clone)
1669
1670/* Functions relating to OpenMP SIMT vectorization transform. */
1671#undef HOOK_PREFIX
1672#define HOOK_PREFIX "TARGET_SIMT_"
1673HOOK_VECTOR (TARGET_SIMT, simt)
1674
1675DEFHOOK
1676(vf,
1677"Return number of threads in SIMT thread group on the target.",
1678int, (void), NULL)
1679
1680HOOK_VECTOR_END (simt)
1681
1682/* Functions relating to openacc. */
1683#undef HOOK_PREFIX
1684#define HOOK_PREFIX "TARGET_GOACC_"
1685HOOK_VECTOR (TARGET_GOACC, goacc)
1686
1687DEFHOOK
1688(validate_dims,
1689"This hook should check the launch dimensions provided for an OpenACC\n\
1690compute region, or routine. Defaulted values are represented as -1\n\
1691and non-constant values as 0. The @var{fn_level} is negative for the\n\
1692function corresponding to the compute region. For a routine is is the\n\
1693outermost level at which partitioned execution may be spawned. The hook\n\
1694should verify non-default values. If DECL is NULL, global defaults\n\
1695are being validated and unspecified defaults should be filled in.\n\
1696Diagnostics should be issued as appropriate. Return\n\
1697true, if changes have been made. You must override this hook to\n\
1698provide dimensions larger than 1.",
1699bool, (tree decl, int *dims, int fn_level),
1700default_goacc_validate_dims)
1701
1702DEFHOOK
1703(dim_limit,
1704"This hook should return the maximum size of a particular dimension,\n\
1705or zero if unbounded.",
1706int, (int axis),
1707default_goacc_dim_limit)
1708
1709DEFHOOK
1710(fork_join,
1711"This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN\n\
1712function calls to target-specific gimple, or indicate whether they\n\
1713should be retained. It is executed during the oacc_device_lower pass.\n\
1714It should return true, if the call should be retained. It should\n\
1715return false, if it is to be deleted (either because target-specific\n\
1716gimple has been inserted before it, or there is no need for it).\n\
1717The default hook returns false, if there are no RTL expanders for them.",
1718bool, (gcall *call, const int *dims, bool is_fork),
1719default_goacc_fork_join)
1720
1721DEFHOOK
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\
1725instructions. @var{call} is gimple statement containing the call to\n\
1726the function. This hook removes statement @var{call} after the\n\
1727expanded sequence has been inserted. This hook is also responsible\n\
1728for allocating any storage for reductions when necessary.",
1729void, (gcall *call),
1730default_goacc_reduction)
1731
1732HOOK_VECTOR_END (goacc)
1733
1734/* Functions relating to vectorization. */
1735#undef HOOK_PREFIX
1736#define HOOK_PREFIX "TARGET_VECTORIZE_"
1737HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1738
1739/* The following member value is a pointer to a function called
1740 by the vectorizer, and return the decl of the target builtin
1741 function. */
1742DEFHOOK
1743(builtin_mask_for_load,
1744 "This hook should return the DECL of a function @var{f} that given an\n\
1745address @var{addr} as an argument returns a mask @var{m} that can be\n\
1746used to extract from two vectors the relevant data that resides in\n\
1747@var{addr} in case @var{addr} is not properly aligned.\n\
1748\n\
1749The autovectorizer, when vectorizing a load operation from an address\n\
1750@var{addr} that may be unaligned, will generate two vector loads from\n\
1751the two aligned addresses around @var{addr}. It then generates a\n\
1752@code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1753two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1754@var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1755the third argument, @var{OFF}, defines how the data will be extracted\n\
1756from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1757@var{v2}; otherwise, the returned vector is composed from the last\n\
1758@var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1759@var{OFF} elements of @var{v2}.\n\
1760\n\
1761If this hook is defined, the autovectorizer will generate a call\n\
1762to @var{f} (using the DECL tree that this hook returns) and will\n\
1763use the return value of @var{f} as the argument @var{OFF} to\n\
1764@code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1765should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1766described above.\n\
1767If this hook is not defined, then @var{addr} will be used as\n\
1768the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1769log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1770 tree, (void), NULL)
1771
1772/* Returns a built-in function that realizes the vectorized version of
1773 a target-independent function, or NULL_TREE if not available. */
1774DEFHOOK
1775(builtin_vectorized_function,
1776 "This hook should return the decl of a function that implements the\n\
1777vectorized variant of the function with the @code{combined_fn} code\n\
1778@var{code} or @code{NULL_TREE} if such a function is not available.\n\
1779The return type of the vectorized function shall be of vector type\n\
1780@var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1781 tree, (unsigned code, tree vec_type_out, tree vec_type_in),
1782 default_builtin_vectorized_function)
1783
1784/* Returns a built-in function that realizes the vectorized version of
1785 a target-specific function, or NULL_TREE if not available. */
1786DEFHOOK
1787(builtin_md_vectorized_function,
1788 "This hook should return the decl of a function that implements the\n\
1789vectorized variant of target built-in function @code{fndecl}. The\n\
1790return type of the vectorized function shall be of vector type\n\
1791@var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1792 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1793 default_builtin_md_vectorized_function)
1794
1795/* Returns a function declaration for a builtin that realizes the
1796 vector conversion, or NULL_TREE if not available. */
1797DEFHOOK
1798(builtin_conversion,
1799 "This hook should return the DECL of a function that implements conversion of the\n\
1800input vector of type @var{src_type} to type @var{dest_type}.\n\
1801The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1802specifies how the conversion is to be applied\n\
1803(truncation, rounding, etc.).\n\
1804\n\
1805If this hook is defined, the autovectorizer will use the\n\
1806@code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1807conversion. Otherwise, it will return @code{NULL_TREE}.",
1808 tree, (unsigned code, tree dest_type, tree src_type),
1809 default_builtin_vectorized_conversion)
1810
1811/* Cost of different vector/scalar statements in vectorization cost
1812 model. In case of misaligned vector loads and stores the cost depends
1813 on the data type and misalignment value. */
1814DEFHOOK
1815(builtin_vectorization_cost,
1816 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1817For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1818misalignment value (@var{misalign}).",
1819 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1820 default_builtin_vectorization_cost)
1821
1822DEFHOOK
1823(preferred_vector_alignment,
1824 "This hook returns the preferred alignment in bits for accesses to\n\
1825vectors of type @var{type} in vectorized code. This might be less than\n\
1826or greater than the ABI-defined value returned by\n\
1827@code{TARGET_VECTOR_ALIGNMENT}. It can be equal to the alignment of\n\
1828a single element, in which case the vectorizer will not try to optimize\n\
1829for alignment.\n\
1830\n\
1831The default hook returns @code{TYPE_ALIGN (@var{type})}, which is\n\
1832correct for most targets.",
1833 HOST_WIDE_INT, (const_tree type),
1834 default_preferred_vector_alignment)
1835
1836/* Return true if vector alignment is reachable (by peeling N
1837 iterations) for the given scalar type. */
1838DEFHOOK
1839(vector_alignment_reachable,
1840 "Return true if vector alignment is reachable (by peeling N iterations) for the given scalar type @var{type}. @var{is_packed} is false if the scalar access using @var{type} is known to be naturally aligned.",
1841 bool, (const_tree type, bool is_packed),
1842 default_builtin_vector_alignment_reachable)
1843
1844/* Return true if a vector created for vec_perm_const is valid.
1845 A NULL indicates that all constants are valid permutations. */
1846DEFHOOK
1847(vec_perm_const_ok,
1848 "Return true if a vector created for @code{vec_perm_const} is valid.",
1849 bool, (machine_mode, vec_perm_indices),
1850 NULL)
1851
1852/* Return true if the target supports misaligned store/load of a
1853 specific factor denoted in the third parameter. The last parameter
1854 is true if the access is defined in a packed struct. */
1855DEFHOOK
1856(support_vector_misalignment,
1857 "This hook should return true if the target supports misaligned vector\n\
1858store/load of a specific factor denoted in the @var{misalignment}\n\
1859parameter. The vector store/load should be of machine mode @var{mode} and\n\
1860the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1861parameter is true if the memory access is defined in a packed struct.",
1862 bool,
1863 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1864 default_builtin_support_vector_misalignment)
1865
1866/* Returns the preferred mode for SIMD operations for the specified
1867 scalar mode. */
1868DEFHOOK
1869(preferred_simd_mode,
1870 "This hook should return the preferred mode for vectorizing scalar\n\
1871mode @var{mode}. The default is\n\
1872equal to @code{word_mode}, because the vectorizer can do some\n\
1873transformations even in absence of specialized @acronym{SIMD} hardware.",
1874 machine_mode,
1875 (scalar_mode mode),
1876 default_preferred_simd_mode)
1877
1878/* Returns a mask of vector sizes to iterate over when auto-vectorizing
1879 after processing the preferred one derived from preferred_simd_mode. */
1880DEFHOOK
1881(autovectorize_vector_sizes,
1882 "This hook should return a mask of sizes that should be iterated over\n\
1883after trying to autovectorize using the vector size derived from the\n\
1884mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1885The default is zero which means to not iterate over other vector sizes.",
1886 unsigned int,
1887 (void),
1888 default_autovectorize_vector_sizes)
1889
1890/* Function to get a target mode for a vector mask. */
1891DEFHOOK
1892(get_mask_mode,
1893 "A vector mask is a value that holds one boolean result for every element\n\
1894in a vector. This hook returns the machine mode that should be used to\n\
1895represent such a mask when the vector in question is @var{length} bytes\n\
1896long and contains @var{nunits} elements. The hook returns an empty\n\
1897@code{opt_machine_mode} if no such mode exists.\n\
1898\n\
1899The default implementation returns the mode of an integer vector that\n\
1900is @var{length} bytes long and that contains @var{nunits} elements,\n\
1901if such a mode exists.",
1902 opt_machine_mode,
1903 (unsigned nunits, unsigned length),
1904 default_get_mask_mode)
1905
1906/* Target builtin that implements vector gather operation. */
1907DEFHOOK
1908(builtin_gather,
1909 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1910is the vector type of the load and @var{index_type} is scalar type of\n\
1911the index, scaled by @var{scale}.\n\
1912The default is @code{NULL_TREE} which means to not vectorize gather\n\
1913loads.",
1914 tree,
1915 (const_tree mem_vectype, const_tree index_type, int scale),
1916 NULL)
1917
1918/* Target builtin that implements vector scatter operation. */
1919DEFHOOK
1920(builtin_scatter,
1921"Target builtin that implements vector scatter operation. @var{vectype}\n\
1922is the vector type of the store and @var{index_type} is scalar type of\n\
1923the index, scaled by @var{scale}.\n\
1924The default is @code{NULL_TREE} which means to not vectorize scatter\n\
1925stores.",
1926 tree,
1927 (const_tree vectype, const_tree index_type, int scale),
1928 NULL)
1929
1930/* Target function to initialize the cost model for a loop or block. */
1931DEFHOOK
1932(init_cost,
1933 "This hook should initialize target-specific data structures in preparation "
1934 "for modeling the costs of vectorizing a loop or basic block. The default "
1935 "allocates three unsigned integers for accumulating costs for the prologue, "
1936 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
1937 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1938 "is being vectorized.",
1939 void *,
1940 (struct loop *loop_info),
1941 default_init_cost)
1942
1943/* Target function to record N statements of the given kind using the
1944 given vector type within the cost model data for the current loop or
1945 block. */
1946DEFHOOK
1947(add_stmt_cost,
1948 "This hook should update the target-specific @var{data} in response to "
1949 "adding @var{count} copies of the given @var{kind} of statement to a "
1950 "loop or basic block. The default adds the builtin vectorizer cost for "
1951 "the copies of the statement to the accumulator specified by @var{where}, "
1952 "(the prologue, body, or epilogue) and returns the amount added. The "
1953 "return value should be viewed as a tentative cost that may later be "
1954 "revised.",
1955 unsigned,
1956 (void *data, int count, enum vect_cost_for_stmt kind,
1957 struct _stmt_vec_info *stmt_info, int misalign,
1958 enum vect_cost_model_location where),
1959 default_add_stmt_cost)
1960
1961/* Target function to calculate the total cost of the current vectorized
1962 loop or block. */
1963DEFHOOK
1964(finish_cost,
1965 "This hook should complete calculations of the cost of vectorizing a loop "
1966 "or basic block based on @var{data}, and return the prologue, body, and "
1967 "epilogue costs as unsigned integers. The default returns the value of "
1968 "the three accumulators.",
1969 void,
1970 (void *data, unsigned *prologue_cost, unsigned *body_cost,
1971 unsigned *epilogue_cost),
1972 default_finish_cost)
1973
1974/* Function to delete target-specific cost modeling data. */
1975DEFHOOK
1976(destroy_cost_data,
1977 "This hook should release @var{data} and any related data structures "
1978 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
1979 "accumulator.",
1980 void,
1981 (void *data),
1982 default_destroy_cost_data)
1983
1984HOOK_VECTOR_END (vectorize)
1985
1986#undef HOOK_PREFIX
1987#define HOOK_PREFIX "TARGET_"
1988
1989DEFHOOK
1990(record_offload_symbol,
1991 "Used when offloaded functions are seen in the compilation unit and no named\n\
1992sections are available. It is called once for each symbol that must be\n\
1993recorded in the offload function and variable table.",
1994 void, (tree),
1995 hook_void_tree)
1996
1997DEFHOOKPOD
1998(absolute_biggest_alignment,
1999 "If defined, this target hook specifies the absolute biggest alignment\n\
2000that a type or variable can have on this machine, otherwise,\n\
2001@code{BIGGEST_ALIGNMENT} is used.",
2002 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
2003
2004/* Allow target specific overriding of option settings after options have
2005 been changed by an attribute or pragma or when it is reset at the
2006 end of the code affected by an attribute or pragma. */
2007DEFHOOK
2008(override_options_after_change,
2009 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
2010but is called when the optimize level is changed via an attribute or\n\
2011pragma or when it is reset at the end of the code affected by the\n\
2012attribute or pragma. It is not called at the beginning of compilation\n\
2013when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
2014actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
2015@code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
2016 void, (void),
2017 hook_void_void)
2018
2019DEFHOOK
2020(offload_options,
2021 "Used when writing out the list of options into an LTO file. It should\n\
2022translate any relevant target-specific options (such as the ABI in use)\n\
2023into one of the @option{-foffload} options that exist as a common interface\n\
2024to express such options. It should return a string containing these options,\n\
2025separated by spaces, which the caller will free.\n",
2026char *, (void), hook_charptr_void_null)
2027
2028DEFHOOK_UNDOC
2029(eh_return_filter_mode,
2030 "Return machine mode for filter value.",
2031 scalar_int_mode, (void),
2032 default_eh_return_filter_mode)
2033
2034/* Return machine mode for libgcc expanded cmp instructions. */
2035DEFHOOK
2036(libgcc_cmp_return_mode,
2037 "This target hook should return the mode to be used for the return value\n\
2038of compare instructions expanded to libgcc calls. If not defined\n\
2039@code{word_mode} is returned which is the right choice for a majority of\n\
2040targets.",
2041 scalar_int_mode, (void),
2042 default_libgcc_cmp_return_mode)
2043
2044/* Return machine mode for libgcc expanded shift instructions. */
2045DEFHOOK
2046(libgcc_shift_count_mode,
2047 "This target hook should return the mode to be used for the shift count operand\n\
2048of shift instructions expanded to libgcc calls. If not defined\n\
2049@code{word_mode} is returned which is the right choice for a majority of\n\
2050targets.",
2051 scalar_int_mode, (void),
2052 default_libgcc_shift_count_mode)
2053
2054/* Return machine mode to be used for _Unwind_Word type. */
2055DEFHOOK
2056(unwind_word_mode,
2057 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
2058The default is to use @code{word_mode}.",
2059 scalar_int_mode, (void),
2060 default_unwind_word_mode)
2061
2062/* Given two decls, merge their attributes and return the result. */
2063DEFHOOK
2064(merge_decl_attributes,
2065 "Define this target hook if the merging of decl attributes needs special\n\
2066handling. If defined, the result is a list of the combined\n\
2067@code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2068@var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2069when this is needed are when one attribute overrides another, or when an\n\
2070attribute is nullified by a subsequent definition. This function may\n\
2071call @code{merge_attributes} to handle machine-independent merging.\n\
2072\n\
2073@findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2074If the only target-specific handling you require is @samp{dllimport}\n\
2075for Microsoft Windows targets, you should define the macro\n\
2076@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2077will then define a function called\n\
2078@code{merge_dllimport_decl_attributes} which can then be defined as\n\
2079the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2080add @code{handle_dll_attribute} in the attribute table for your port\n\
2081to perform initial processing of the @samp{dllimport} and\n\
2082@samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2083@file{i386/i386.c}, for example.",
2084 tree, (tree olddecl, tree newdecl),
2085 merge_decl_attributes)
2086
2087/* Given two types, merge their attributes and return the result. */
2088DEFHOOK
2089(merge_type_attributes,
2090 "Define this target hook if the merging of type attributes needs special\n\
2091handling. If defined, the result is a list of the combined\n\
2092@code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2093that @code{comptypes} has already been called and returned 1. This\n\
2094function may call @code{merge_attributes} to handle machine-independent\n\
2095merging.",
2096 tree, (tree type1, tree type2),
2097 merge_type_attributes)
2098
2099/* Table of machine attributes and functions to handle them.
2100 Ignored if NULL. */
2101DEFHOOKPOD
2102(attribute_table,
2103 "If defined, this target hook points to an array of @samp{struct\n\
2104attribute_spec} (defined in @file{tree-core.h}) specifying the machine\n\
2105specific attributes for this target and some of the restrictions on the\n\
2106entities to which these attributes are applied and the arguments they\n\
2107take.",
2108 const struct attribute_spec *, NULL)
2109
2110/* Return true iff attribute NAME expects a plain identifier as its first
2111 argument. */
2112DEFHOOK
2113(attribute_takes_identifier_p,
2114 "If defined, this target hook is a function which returns true if the\n\
2115machine-specific attribute named @var{name} expects an identifier\n\
2116given as its first argument to be passed on as a plain identifier, not\n\
2117subjected to name lookup. If this is not defined, the default is\n\
2118false for all machine-specific attributes.",
2119 bool, (const_tree name),
2120 hook_bool_const_tree_false)
2121
2122/* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2123 one if they are compatible and two if they are nearly compatible
2124 (which causes a warning to be generated). */
2125DEFHOOK
2126(comp_type_attributes,
2127 "If defined, this target hook is a function which returns zero if the attributes on\n\
2128@var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2129and two if they are nearly compatible (which causes a warning to be\n\
2130generated). If this is not defined, machine-specific attributes are\n\
2131supposed always to be compatible.",
2132 int, (const_tree type1, const_tree type2),
2133 hook_int_const_tree_const_tree_1)
2134
2135/* Assign default attributes to the newly defined TYPE. */
2136DEFHOOK
2137(set_default_type_attributes,
2138 "If defined, this target hook is a function which assigns default attributes to\n\
2139the newly defined @var{type}.",
2140 void, (tree type),
2141 hook_void_tree)
2142
2143/* Insert attributes on the newly created DECL. */
2144DEFHOOK
2145(insert_attributes,
2146 "Define this target hook if you want to be able to add attributes to a decl\n\
2147when it is being created. This is normally useful for back ends which\n\
2148wish to implement a pragma by using the attributes which correspond to\n\
2149the pragma's effect. The @var{node} argument is the decl which is being\n\
2150created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2151for this decl. The list itself should not be modified, since it may be\n\
2152shared with other decls, but attributes may be chained on the head of\n\
2153the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2154attributes, or a copy of the list may be made if further changes are\n\
2155needed.",
2156 void, (tree node, tree *attr_ptr),
2157 hook_void_tree_treeptr)
2158
2159/* Return true if FNDECL (which has at least one machine attribute)
2160 can be inlined despite its machine attributes, false otherwise. */
2161DEFHOOK
2162(function_attribute_inlinable_p,
2163 "@cindex inlining\n\
2164This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2165into the current function, despite its having target-specific\n\
2166attributes, @code{false} otherwise. By default, if a function has a\n\
2167target specific attribute attached to it, it will not be inlined.",
2168 bool, (const_tree fndecl),
2169 hook_bool_const_tree_false)
2170
2171/* Return true if bitfields in RECORD_TYPE should follow the
2172 Microsoft Visual C++ bitfield layout rules. */
2173DEFHOOK
2174(ms_bitfield_layout_p,
2175 "This target hook returns @code{true} if bit-fields in the given\n\
2176@var{record_type} are to be laid out following the rules of Microsoft\n\
2177Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2178unit with the previous bit-field if their underlying types have\n\
2179different sizes, and the bit-field will be aligned to the highest\n\
2180alignment of the underlying types of itself and of the previous\n\
2181bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2182the whole enclosing structure, even if it is unnamed; except that\n\
2183(iii) a zero-sized bit-field will be disregarded unless it follows\n\
2184another bit-field of nonzero size. If this hook returns @code{true},\n\
2185other macros that control bit-field layout are ignored.\n\
2186\n\
2187When a bit-field is inserted into a packed record, the whole size\n\
2188of the underlying type is used by one or more same-size adjacent\n\
2189bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2190and any additional adjacent long bit-fields are packed into the same\n\
2191chunk of 32 bits. However, if the size changes, a new field of that\n\
2192size is allocated). In an unpacked record, this is the same as using\n\
2193alignment, but not equivalent when packing.\n\
2194\n\
2195If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2196the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2197used on a single field when MS bit-fields are in use, it will take\n\
2198precedence for that field, but the alignment of the rest of the structure\n\
2199may affect its placement.",
2200 bool, (const_tree record_type),
2201 hook_bool_const_tree_false)
2202
2203/* For now this is only an interface to WORDS_BIG_ENDIAN for
2204 target-independent code like the front ends, need performance testing
2205 before switching completely to the target hook. */
2206DEFHOOK_UNDOC
2207(words_big_endian,
2208 "",
2209 bool, (void),
2210 targhook_words_big_endian)
2211
2212/* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2213DEFHOOK_UNDOC
2214(float_words_big_endian,
2215 "",
2216 bool, (void),
2217 targhook_float_words_big_endian)
2218
2219DEFHOOK
2220(float_exceptions_rounding_supported_p,
2221 "Returns true if the target supports IEEE 754 floating-point exceptions\
2222 and rounding modes, false otherwise. This is intended to relate to the\
2223 @code{float} and @code{double} types, but not necessarily @code{long double}.\
2224 By default, returns true if the @code{adddf3} instruction pattern is\
2225 available and false otherwise, on the assumption that hardware floating\
2226 point supports exceptions and rounding modes but software floating point\
2227 does not.",
2228 bool, (void),
2229 default_float_exceptions_rounding_supported_p)
2230
2231/* True if the target supports decimal floating point. */
2232DEFHOOK
2233(decimal_float_supported_p,
2234 "Returns true if the target supports decimal floating point.",
2235 bool, (void),
2236 default_decimal_float_supported_p)
2237
2238/* True if the target supports fixed-point. */
2239DEFHOOK
2240(fixed_point_supported_p,
2241 "Returns true if the target supports fixed-point arithmetic.",
2242 bool, (void),
2243 default_fixed_point_supported_p)
2244
2245/* Return true if anonymous bitfields affect structure alignment. */
2246DEFHOOK
2247(align_anon_bitfield,
2248 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2249whether unnamed bitfields affect the alignment of the containing\n\
2250structure. The hook should return true if the structure should inherit\n\
2251the alignment requirements of an unnamed bitfield's type.",
2252 bool, (void),
2253 hook_bool_void_false)
2254
2255/* Return true if volatile bitfields should use the narrowest type possible.
2256 Return false if they should use the container type. */
2257DEFHOOK
2258(narrow_volatile_bitfield,
2259 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2260should use the narrowest mode possible. It should return @code{false} if\n\
2261these accesses should use the bitfield container type.\n\
2262\n\
2263The default is @code{false}.",
2264 bool, (void),
2265 hook_bool_void_false)
2266
2267/* Set up target-specific built-in functions. */
2268DEFHOOK
2269(init_builtins,
2270 "Define this hook if you have any machine-specific built-in functions\n\
2271that need to be defined. It should be a function that performs the\n\
2272necessary setup.\n\
2273\n\
2274Machine specific built-in functions can be useful to expand special machine\n\
2275instructions that would otherwise not normally be generated because\n\
2276they have no equivalent in the source language (for example, SIMD vector\n\
2277instructions or prefetch instructions).\n\
2278\n\
2279To create a built-in function, call the function\n\
2280@code{lang_hooks.builtin_function}\n\
2281which is defined by the language front end. You can use any type nodes set\n\
2282up by @code{build_common_tree_nodes};\n\
2283only language front ends that use those two functions will call\n\
2284@samp{TARGET_INIT_BUILTINS}.",
2285 void, (void),
2286 hook_void_void)
2287
2288/* Initialize (if INITIALIZE_P is true) and return the target-specific
2289 built-in function decl for CODE.
2290 Return NULL if that is not possible. Return error_mark_node if CODE
2291 is outside of the range of valid target builtin function codes. */
2292DEFHOOK
2293(builtin_decl,
2294 "Define this hook if you have any machine-specific built-in functions\n\
2295that need to be defined. It should be a function that returns the\n\
2296builtin function declaration for the builtin function code @var{code}.\n\
2297If there is no such builtin and it cannot be initialized at this time\n\
2298if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2299If @var{code} is out of range the function should return\n\
2300@code{error_mark_node}.",
2301 tree, (unsigned code, bool initialize_p), NULL)
2302
2303/* Expand a target-specific builtin. */
2304DEFHOOK
2305(expand_builtin,
2306 "\n\
2307Expand a call to a machine specific built-in function that was set up by\n\
2308@samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2309function call; the result should go to @var{target} if that is\n\
2310convenient, and have mode @var{mode} if that is convenient.\n\
2311@var{subtarget} may be used as the target for computing one of\n\
2312@var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2313ignored. This function should return the result of the call to the\n\
2314built-in function.",
2315 rtx,
2316 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2317 default_expand_builtin)
2318
2319DEFHOOK
2320(builtin_chkp_function,
2321 "This hook allows target to redefine built-in functions used by\n\
2322Pointer Bounds Checker for code instrumentation. Hook should return\n\
2323fndecl of function implementing generic builtin whose code is\n\
2324passed in @var{fcode}. Currently following built-in functions are\n\
2325obtained using this hook:\n\
2326@deftypefn {Built-in Function} __bounds_type __chkp_bndmk (const void *@var{lb}, size_t @var{size})\n\
2327Function code - BUILT_IN_CHKP_BNDMK. This built-in function is used\n\
2328by Pointer Bounds Checker to create bound values. @var{lb} holds low\n\
2329bound of the resulting bounds. @var{size} holds size of created bounds.\n\
2330@end deftypefn\n\
2331\n\
2332@deftypefn {Built-in Function} void __chkp_bndstx (const void *@var{ptr}, __bounds_type @var{b}, const void **@var{loc})\n\
2333Function code - @code{BUILT_IN_CHKP_BNDSTX}. This built-in function is used\n\
2334by Pointer Bounds Checker to store bounds @var{b} for pointer @var{ptr}\n\
2335when @var{ptr} is stored by address @var{loc}.\n\
2336@end deftypefn\n\
2337\n\
2338@deftypefn {Built-in Function} __bounds_type __chkp_bndldx (const void **@var{loc}, const void *@var{ptr})\n\
2339Function code - @code{BUILT_IN_CHKP_BNDLDX}. This built-in function is used\n\
2340by Pointer Bounds Checker to get bounds of pointer @var{ptr} loaded by\n\
2341address @var{loc}.\n\
2342@end deftypefn\n\
2343\n\
2344@deftypefn {Built-in Function} void __chkp_bndcl (const void *@var{ptr}, __bounds_type @var{b})\n\
2345Function code - @code{BUILT_IN_CHKP_BNDCL}. This built-in function is used\n\
2346by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2347lower bound of bounds @var{b}.\n\
2348@end deftypefn\n\
2349\n\
2350@deftypefn {Built-in Function} void __chkp_bndcu (const void *@var{ptr}, __bounds_type @var{b})\n\
2351Function code - @code{BUILT_IN_CHKP_BNDCU}. This built-in function is used\n\
2352by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2353upper bound of bounds @var{b}.\n\
2354@end deftypefn\n\
2355\n\
2356@deftypefn {Built-in Function} __bounds_type __chkp_bndret (void *@var{ptr})\n\
2357Function code - @code{BUILT_IN_CHKP_BNDRET}. This built-in function is used\n\
2358by Pointer Bounds Checker to obtain bounds returned by a call statement.\n\
2359@var{ptr} passed to built-in is @code{SSA_NAME} returned by the call.\n\
2360@end deftypefn\n\
2361\n\
2362@deftypefn {Built-in Function} __bounds_type __chkp_intersect (__bounds_type @var{b1}, __bounds_type @var{b2})\n\
2363Function code - @code{BUILT_IN_CHKP_INTERSECT}. This built-in function\n\
2364returns intersection of bounds @var{b1} and @var{b2}.\n\
2365@end deftypefn\n\
2366\n\
2367@deftypefn {Built-in Function} __bounds_type __chkp_narrow (const void *@var{ptr}, __bounds_type @var{b}, size_t @var{s})\n\
2368Function code - @code{BUILT_IN_CHKP_NARROW}. This built-in function\n\
2369returns intersection of bounds @var{b} and\n\
2370[@var{ptr}, @var{ptr} + @var{s} - @code{1}].\n\
2371@end deftypefn\n\
2372\n\
2373@deftypefn {Built-in Function} size_t __chkp_sizeof (const void *@var{ptr})\n\
2374Function code - @code{BUILT_IN_CHKP_SIZEOF}. This built-in function\n\
2375returns size of object referenced by @var{ptr}. @var{ptr} is always\n\
2376@code{ADDR_EXPR} of @code{VAR_DECL}. This built-in is used by\n\
2377Pointer Bounds Checker when bounds of object cannot be computed statically\n\
2378(e.g. object has incomplete type).\n\
2379@end deftypefn\n\
2380\n\
2381@deftypefn {Built-in Function} const void *__chkp_extract_lower (__bounds_type @var{b})\n\
2382Function code - @code{BUILT_IN_CHKP_EXTRACT_LOWER}. This built-in function\n\
2383returns lower bound of bounds @var{b}.\n\
2384@end deftypefn\n\
2385\n\
2386@deftypefn {Built-in Function} const void *__chkp_extract_upper (__bounds_type @var{b})\n\
2387Function code - @code{BUILT_IN_CHKP_EXTRACT_UPPER}. This built-in function\n\
2388returns upper bound of bounds @var{b}.\n\
2389@end deftypefn",
2390 tree, (unsigned fcode),
2391 default_builtin_chkp_function)
2392
2393DEFHOOK
2394(chkp_bound_type,
2395 "Return type to be used for bounds",
2396 tree, (void),
2397 default_chkp_bound_type)
2398
2399DEFHOOK
2400(chkp_bound_mode,
2401 "Return mode to be used for bounds.",
2402 machine_mode, (void),
2403 default_chkp_bound_mode)
2404
2405DEFHOOK
2406(chkp_make_bounds_constant,
2407 "Return constant used to statically initialize constant bounds\n\
2408with specified lower bound @var{lb} and upper bounds @var{ub}.",
2409 tree, (HOST_WIDE_INT lb, HOST_WIDE_INT ub),
2410 default_chkp_make_bounds_constant)
2411
2412DEFHOOK
2413(chkp_initialize_bounds,
2414 "Generate a list of statements @var{stmts} to initialize pointer\n\
2415bounds variable @var{var} with bounds @var{lb} and @var{ub}. Return\n\
2416the number of generated statements.",
2417 int, (tree var, tree lb, tree ub, tree *stmts),
2418 default_chkp_initialize_bounds)
2419
2420/* Select a replacement for a target-specific builtin. This is done
2421 *before* regular type checking, and so allows the target to
2422 implement a crude form of function overloading. The result is a
2423 complete expression that implements the operation. PARAMS really
2424 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2425DEFHOOK
2426(resolve_overloaded_builtin,
2427 "Select a replacement for a machine specific built-in function that\n\
2428was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2429@emph{before} regular type checking, and so allows the target to\n\
2430implement a crude form of function overloading. @var{fndecl} is the\n\
2431declaration of the built-in function. @var{arglist} is the list of\n\
2432arguments passed to the built-in function. The result is a\n\
2433complete expression that implements the operation, usually\n\
2434another @code{CALL_EXPR}.\n\
2435@var{arglist} really has type @samp{VEC(tree,gc)*}",
2436 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2437
2438/* Fold a target-specific builtin to a tree valid for both GIMPLE
2439 and GENERIC. */
2440DEFHOOK
2441(fold_builtin,
2442 "Fold a call to a machine specific built-in function that was set up by\n\
2443@samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2444built-in function. @var{n_args} is the number of arguments passed to\n\
2445the function; the arguments themselves are pointed to by @var{argp}.\n\
2446The result is another tree, valid for both GIMPLE and GENERIC,\n\
2447containing a simplified expression for the call's result. If\n\
2448@var{ignore} is true the value will be ignored.",
2449 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2450 hook_tree_tree_int_treep_bool_null)
2451
2452/* Fold a target-specific builtin to a valid GIMPLE tree. */
2453DEFHOOK
2454(gimple_fold_builtin,
2455 "Fold a call to a machine specific built-in function that was set up\n\
2456by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2457statement holding the function call. Returns true if any change\n\
2458was made to the GIMPLE stream.",
2459 bool, (gimple_stmt_iterator *gsi),
2460 hook_bool_gsiptr_false)
2461
2462/* Target hook is used to compare the target attributes in two functions to
2463 determine which function's features get higher priority. This is used
2464 during function multi-versioning to figure out the order in which two
2465 versions must be dispatched. A function version with a higher priority
2466 is checked for dispatching earlier. DECL1 and DECL2 are
2467 the two function decls that will be compared. It returns positive value
2468 if DECL1 is higher priority, negative value if DECL2 is higher priority
2469 and 0 if they are the same. */
2470DEFHOOK
2471(compare_version_priority,
2472 "This hook is used to compare the target attributes in two functions to\n\
2473determine which function's features get higher priority. This is used\n\
2474during function multi-versioning to figure out the order in which two\n\
2475versions must be dispatched. A function version with a higher priority\n\
2476is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2477 the two function decls that will be compared.",
2478 int, (tree decl1, tree decl2), NULL)
2479
2480/* Target hook is used to generate the dispatcher logic to invoke the right
2481 function version at run-time for a given set of function versions.
2482 ARG points to the callgraph node of the dispatcher function whose body
2483 must be generated. */
2484DEFHOOK
2485(generate_version_dispatcher_body,
2486 "This hook is used to generate the dispatcher logic to invoke the right\n\
2487function version at run-time for a given set of function versions.\n\
2488@var{arg} points to the callgraph node of the dispatcher function whose\n\
2489body must be generated.",
2490 tree, (void *arg), NULL)
2491
2492/* Target hook is used to get the dispatcher function for a set of function
2493 versions. The dispatcher function is called to invoke the right function
2494 version at run-time. DECL is one version from a set of semantically
2495 identical versions. */
2496DEFHOOK
2497(get_function_versions_dispatcher,
2498 "This hook is used to get the dispatcher function for a set of function\n\
2499versions. The dispatcher function is called to invoke the right function\n\
2500version at run-time. @var{decl} is one version from a set of semantically\n\
2501identical versions.",
2502 tree, (void *decl), NULL)
2503
2504/* Returns a code for a target-specific builtin that implements
2505 reciprocal of a target-specific function, or NULL_TREE if not available. */
2506DEFHOOK
2507(builtin_reciprocal,
2508 "This hook should return the DECL of a function that implements the\n\
2509reciprocal of the machine-specific builtin function @var{fndecl}, or\n\
2510@code{NULL_TREE} if such a function is not available.",
2511 tree, (tree fndecl),
2512 default_builtin_reciprocal)
2513
2514/* For a vendor-specific TYPE, return a pointer to a statically-allocated
2515 string containing the C++ mangling for TYPE. In all other cases, return
2516 NULL. */
2517DEFHOOK
2518(mangle_type,
2519 "If your target defines any fundamental types, or any types your target\n\
2520uses should be mangled differently from the default, define this hook\n\
2521to return the appropriate encoding for these types as part of a C++\n\
2522mangled name. The @var{type} argument is the tree structure representing\n\
2523the type to be mangled. The hook may be applied to trees which are\n\
2524not target-specific fundamental types; it should return @code{NULL}\n\
2525for all such types, as well as arguments it does not recognize. If the\n\
2526return value is not @code{NULL}, it must point to a statically-allocated\n\
2527string constant.\n\
2528\n\
2529Target-specific fundamental types might be new fundamental types or\n\
2530qualified versions of ordinary fundamental types. Encode new\n\
2531fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2532is the name used for the type in source code, and @var{n} is the\n\
2533length of @var{name} in decimal. Encode qualified versions of\n\
2534ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2535@var{name} is the name used for the type qualifier in source code,\n\
2536@var{n} is the length of @var{name} as above, and @var{code} is the\n\
2537code used to represent the unqualified version of this type. (See\n\
2538@code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2539codes.) In both cases the spaces are for clarity; do not include any\n\
2540spaces in your string.\n\
2541\n\
2542This hook is applied to types prior to typedef resolution. If the mangled\n\
2543name for a particular type depends only on that type's main variant, you\n\
2544can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2545before mangling.\n\
2546\n\
2547The default version of this hook always returns @code{NULL}, which is\n\
2548appropriate for a target that does not define any new fundamental\n\
2549types.",
2550 const char *, (const_tree type),
2551 hook_constcharptr_const_tree_null)
2552
2553/* Make any adjustments to libfunc names needed for this target. */
2554DEFHOOK
2555(init_libfuncs,
2556 "This hook should declare additional library routines or rename\n\
2557existing ones, using the functions @code{set_optab_libfunc} and\n\
2558@code{init_one_libfunc} defined in @file{optabs.c}.\n\
2559@code{init_optabs} calls this macro after initializing all the normal\n\
2560library routines.\n\
2561\n\
2562The default is to do nothing. Most ports don't need to define this hook.",
2563 void, (void),
2564 hook_void_void)
2565
2566 /* Add a __gnu_ prefix to library functions rather than just __. */
2567DEFHOOKPOD
2568(libfunc_gnu_prefix,
2569 "If false (the default), internal library routines start with two\n\
2570underscores. If set to true, these routines start with @code{__gnu_}\n\
2571instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2572currently only affects functions defined in @file{libgcc2.c}. If this\n\
2573is set to true, the @file{tm.h} file must also\n\
2574@code{#define LIBGCC2_GNU_PREFIX}.",
2575 bool, false)
2576
2577/* Given a decl, a section name, and whether the decl initializer
2578 has relocs, choose attributes for the section. */
2579/* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2580DEFHOOK
2581(section_type_flags,
2582 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2583based on a variable or function decl, a section name, and whether or not the\n\
2584declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2585null, in which case read-write data should be assumed.\n\
2586\n\
2587The default version of this function handles choosing code vs data,\n\
2588read-only vs read-write data, and @code{flag_pic}. You should only\n\
2589need to override this if your target has special flags that might be\n\
2590set via @code{__attribute__}.",
2591 unsigned int, (tree decl, const char *name, int reloc),
2592 default_section_type_flags)
2593
2594DEFHOOK
2595(libc_has_function,
2596 "This hook determines whether a function from a class of functions\n\
2597@var{fn_class} is present at the runtime.",
2598 bool, (enum function_class fn_class),
2599 default_libc_has_function)
2600
2601/* True if new jumps cannot be created, to replace existing ones or
2602 not, at the current point in the compilation. */
2603DEFHOOK
2604(cannot_modify_jumps_p,
2605 "This target hook returns @code{true} past the point in which new jump\n\
2606instructions could be created. On machines that require a register for\n\
2607every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2608reload, so this target hook should be defined to a function such as:\n\
2609\n\
2610@smallexample\n\
2611static bool\n\
2612cannot_modify_jumps_past_reload_p ()\n\
2613@{\n\
2614 return (reload_completed || reload_in_progress);\n\
2615@}\n\
2616@end smallexample",
2617 bool, (void),
2618 hook_bool_void_false)
2619
2620/* True if FOLLOWER may be modified to follow FOLLOWEE. */
2621DEFHOOK
2622(can_follow_jump,
2623 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2624 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2625 false, if it can't.\
2626 For example, on some targets, certain kinds of branches can't be made to\
2627 follow through a hot/cold partitioning.",
2628 bool, (const rtx_insn *follower, const rtx_insn *followee),
2629 hook_bool_const_rtx_insn_const_rtx_insn_true)
2630
2631/* Return a register class for which branch target register
2632 optimizations should be applied. */
2633DEFHOOK
2634(branch_target_register_class,
2635 "This target hook returns a register class for which branch target register\n\
2636optimizations should be applied. All registers in this class should be\n\
2637usable interchangeably. After reload, registers in this class will be\n\
2638re-allocated and loads will be hoisted out of loops and be subjected\n\
2639to inter-block scheduling.",
2640 reg_class_t, (void),
2641 default_branch_target_register_class)
2642
2643/* Return true if branch target register optimizations should include
2644 callee-saved registers that are not already live during the current
2645 function. AFTER_PE_GEN is true if prologues and epilogues have
2646 already been generated. */
2647DEFHOOK
2648(branch_target_register_callee_saved,
2649 "Branch target register optimization will by default exclude callee-saved\n\
2650registers\n\
2651that are not already live during the current function; if this target hook\n\
2652returns true, they will be included. The target code must than make sure\n\
2653that all target registers in the class returned by\n\
2654@samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2655saved. @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2656epilogues have already been generated. Note, even if you only return\n\
2657true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2658to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2659to reserve space for caller-saved target registers.",
2660 bool, (bool after_prologue_epilogue_gen),
2661 hook_bool_bool_false)
2662
2663/* Return true if the target supports conditional execution. */
2664DEFHOOK
2665(have_conditional_execution,
2666 "This target hook returns true if the target supports conditional execution.\n\
2667This target hook is required only when the target has several different\n\
2668modes and they have different conditional execution capability, such as ARM.",
2669 bool, (void),
2670 default_have_conditional_execution)
2671
2672DEFHOOK
2673(gen_ccmp_first,
2674 "This function prepares to emit a comparison insn for the first compare in a\n\
2675 sequence of conditional comparisions. It returns an appropriate comparison\n\
2676 with @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2677 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2678 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2679 compares in the the conditional comparision are generated without error.\n\
2680 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2681 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, int code, tree op0, tree op1),
2682 NULL)
2683
2684DEFHOOK
2685(gen_ccmp_next,
2686 "This function prepares to emit a conditional comparison within a sequence\n\
2687 of conditional comparisons. It returns an appropriate comparison with\n\
2688 @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2689 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2690 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2691 compares in the conditional comparision are generated without error. The\n\
2692 @var{prev} expression is the result of a prior call to @code{gen_ccmp_first}\n\
2693 or @code{gen_ccmp_next}. It may return @code{NULL} if the combination of\n\
2694 @var{prev} and this comparison is not supported, otherwise the result must\n\
2695 be appropriate for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2696 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.\n\
2697 @var{bit_code} is @code{AND} or @code{IOR}, which is the op on the compares.",
2698 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, int cmp_code, tree op0, tree op1, int bit_code),
2699 NULL)
2700
2701/* Return a new value for loop unroll size. */
2702DEFHOOK
2703(loop_unroll_adjust,
2704 "This target hook returns a new value for the number of times @var{loop}\n\
2705should be unrolled. The parameter @var{nunroll} is the number of times\n\
2706the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2707the loop, which is going to be checked for unrolling. This target hook\n\
2708is required only when the target has special constraints like maximum\n\
2709number of memory accesses.",
2710 unsigned, (unsigned nunroll, struct loop *loop),
2711 NULL)
2712
2713/* True if X is a legitimate MODE-mode immediate operand. */
2714DEFHOOK
2715(legitimate_constant_p,
2716 "This hook returns true if @var{x} is a legitimate constant for a\n\
2717@var{mode}-mode immediate operand on the target machine. You can assume that\n\
2718@var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2719\n\
2720The default definition returns true.",
2721 bool, (machine_mode mode, rtx x),
2722 hook_bool_mode_rtx_true)
2723
2724/* True if the constant X cannot be placed in the constant pool. */
2725DEFHOOK
2726(cannot_force_const_mem,
2727 "This hook should return true if @var{x} is of a form that cannot (or\n\
2728should not) be spilled to the constant pool. @var{mode} is the mode\n\
2729of @var{x}.\n\
2730\n\
2731The default version of this hook returns false.\n\
2732\n\
2733The primary reason to define this hook is to prevent reload from\n\
2734deciding that a non-legitimate constant would be better reloaded\n\
2735from the constant pool instead of spilling and reloading a register\n\
2736holding the constant. This restriction is often true of addresses\n\
2737of TLS symbols for various targets.",
2738 bool, (machine_mode mode, rtx x),
2739 hook_bool_mode_rtx_false)
2740
2741DEFHOOK_UNDOC
2742(cannot_copy_insn_p,
2743 "True if the insn @var{x} cannot be duplicated.",
2744 bool, (rtx_insn *), NULL)
2745
2746/* True if X is considered to be commutative. */
2747DEFHOOK
2748(commutative_p,
2749 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2750Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2751PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2752of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2753 bool, (const_rtx x, int outer_code),
2754 hook_bool_const_rtx_commutative_p)
2755
2756/* True if ADDR is an address-expression whose effect depends
2757 on the mode of the memory reference it is used in. */
2758DEFHOOK
2759(mode_dependent_address_p,
2760 "This hook returns @code{true} if memory address @var{addr} in address\n\
2761space @var{addrspace} can have\n\
2762different meanings depending on the machine mode of the memory\n\
2763reference it is used for or if the address is valid for some modes\n\
2764but not others.\n\
2765\n\
2766Autoincrement and autodecrement addresses typically have mode-dependent\n\
2767effects because the amount of the increment or decrement is the size\n\
2768of the operand being addressed. Some machines have other mode-dependent\n\
2769addresses. Many RISC machines have no mode-dependent addresses.\n\
2770\n\
2771You may assume that @var{addr} is a valid address for the machine.\n\
2772\n\
2773The default version of this hook returns @code{false}.",
2774 bool, (const_rtx addr, addr_space_t addrspace),
2775 default_mode_dependent_address_p)
2776
2777/* Given an invalid address X for a given machine mode, try machine-specific
2778 ways to make it legitimate. Return X or an invalid address on failure. */
2779DEFHOOK
2780(legitimize_address,
2781 "This hook is given an invalid memory address @var{x} for an\n\
2782operand of mode @var{mode} and should try to return a valid memory\n\
2783address.\n\
2784\n\
2785@findex break_out_memory_refs\n\
2786@var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2787and @var{oldx} will be the operand that was given to that function to produce\n\
2788@var{x}.\n\
2789\n\
2790The code of the hook should not alter the substructure of\n\
2791@var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2792should return the new @var{x}.\n\
2793\n\
2794It is not necessary for this hook to come up with a legitimate address,\n\
2795with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2796The compiler has standard ways of doing so in all cases. In fact, if\n\
2797the target supports only emulated TLS, it\n\
2798is safe to omit this hook or make it return @var{x} if it cannot find\n\
2799a valid way to legitimize the address. But often a machine-dependent\n\
2800strategy can generate better code.",
2801 rtx, (rtx x, rtx oldx, machine_mode mode),
2802 default_legitimize_address)
2803
2804/* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2805DEFHOOK
2806(delegitimize_address,
2807 "This hook is used to undo the possibly obfuscating effects of the\n\
2808@code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2809macros. Some backend implementations of these macros wrap symbol\n\
2810references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2811addressing modes. This target hook allows GCC's optimizers to understand\n\
2812the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2813into their original form.",
2814 rtx, (rtx x),
2815 delegitimize_mem_from_attrs)
2816
2817/* Given an RTX, return true if it is not ok to emit it into debug info
2818 section. */
2819DEFHOOK
2820(const_not_ok_for_debug_p,
2821 "This hook should return true if @var{x} should not be emitted into\n\
2822debug sections.",
2823 bool, (rtx x),
2824 default_const_not_ok_for_debug_p)
2825
2826/* Given an address RTX, say whether it is valid. */
2827DEFHOOK
2828(legitimate_address_p,
2829 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2830address on the target machine for a memory operand of mode @var{mode}.\n\
2831\n\
2832Legitimate addresses are defined in two variants: a strict variant and a\n\
2833non-strict one. The @var{strict} parameter chooses which variant is\n\
2834desired by the caller.\n\
2835\n\
2836The strict variant is used in the reload pass. It must be defined so\n\
2837that any pseudo-register that has not been allocated a hard register is\n\
2838considered a memory reference. This is because in contexts where some\n\
2839kind of register is required, a pseudo-register with no hard register\n\
2840must be rejected. For non-hard registers, the strict variant should look\n\
2841up the @code{reg_renumber} array; it should then proceed using the hard\n\
2842register number in the array, or treat the pseudo as a memory reference\n\
2843if the array holds @code{-1}.\n\
2844\n\
2845The non-strict variant is used in other passes. It must be defined to\n\
2846accept all pseudo-registers in every context where some kind of\n\
2847register is required.\n\
2848\n\
2849Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2850and an integer are stored inside a @code{const} RTX to mark them as\n\
2851constant. Therefore, there is no need to recognize such sums\n\
2852specifically as legitimate addresses. Normally you would simply\n\
2853recognize any @code{const} as legitimate.\n\
2854\n\
2855Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2856sums that are not marked with @code{const}. It assumes that a naked\n\
2857@code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2858naked constant sums as illegitimate addresses, so that none of them will\n\
2859be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2860\n\
2861@cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2862On some machines, whether a symbolic address is legitimate depends on\n\
2863the section that the address refers to. On these machines, define the\n\
2864target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2865into the @code{symbol_ref}, and then check for it here. When you see a\n\
2866@code{const}, you will have to look inside it to find the\n\
2867@code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2868Format}.\n\
2869\n\
2870@cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2871Some ports are still using a deprecated legacy substitute for\n\
2872this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2873has this syntax:\n\
2874\n\
2875@example\n\
2876#define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2877@end example\n\
2878\n\
2879@noindent\n\
2880and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2881address on the target machine for a memory operand of mode @var{mode}.\n\
2882\n\
2883@findex REG_OK_STRICT\n\
2884Compiler source files that want to use the strict variant of this\n\
2885macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2886@code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2887that case and the non-strict variant otherwise.\n\
2888\n\
2889Using the hook is usually simpler because it limits the number of\n\
2890files that are recompiled when changes are made.",
2891 bool, (machine_mode mode, rtx x, bool strict),
2892 default_legitimate_address_p)
2893
2894/* True if the given constant can be put into an object_block. */
2895DEFHOOK
2896(use_blocks_for_constant_p,
2897 "This hook should return true if pool entries for constant @var{x} can\n\
2898be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2899of @var{x}.\n\
2900\n\
2901The default version returns false for all constants.",
2902 bool, (machine_mode mode, const_rtx x),
2903 hook_bool_mode_const_rtx_false)
2904
2905/* True if the given decl can be put into an object_block. */
2906DEFHOOK
2907(use_blocks_for_decl_p,
2908 "This hook should return true if pool entries for @var{decl} should\n\
2909be placed in an @code{object_block} structure.\n\
2910\n\
2911The default version returns true for all decls.",
2912 bool, (const_tree decl),
2913 hook_bool_const_tree_true)
2914
2915/* The minimum and maximum byte offsets for anchored addresses. */
2916DEFHOOKPOD
2917(min_anchor_offset,
2918 "The minimum offset that should be applied to a section anchor.\n\
2919On most targets, it should be the smallest offset that can be\n\
2920applied to a base register while still giving a legitimate address\n\
2921for every mode. The default value is 0.",
2922 HOST_WIDE_INT, 0)
2923
2924DEFHOOKPOD
2925(max_anchor_offset,
2926 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2927offset that should be applied to section anchors. The default\n\
2928value is 0.",
2929 HOST_WIDE_INT, 0)
2930
2931/* True if section anchors can be used to access the given symbol. */
2932DEFHOOK
2933(use_anchors_for_symbol_p,
2934 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2935@var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2936@samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2937\n\
2938The default version is correct for most targets, but you might need to\n\
2939intercept this hook to handle things like target-specific attributes\n\
2940or target-specific sections.",
2941 bool, (const_rtx x),
2942 default_use_anchors_for_symbol_p)
2943
2944/* True if target supports indirect functions. */
2945DEFHOOK
2946(has_ifunc_p,
2947 "It returns true if the target supports GNU indirect functions.\n\
2948The support includes the assembler, linker and dynamic linker.\n\
2949The default value of this hook is based on target's libc.",
2950 bool, (void),
2951 default_has_ifunc_p)
2952
2953/* True if it is OK to do sibling call optimization for the specified
2954 call expression EXP. DECL will be the called function, or NULL if
2955 this is an indirect call. */
2956DEFHOOK
2957(function_ok_for_sibcall,
2958 "True if it is OK to do sibling call optimization for the specified\n\
2959call expression @var{exp}. @var{decl} will be the called function,\n\
2960or @code{NULL} if this is an indirect call.\n\
2961\n\
2962It is not uncommon for limitations of calling conventions to prevent\n\
2963tail calls to functions outside the current unit of translation, or\n\
2964during PIC compilation. The hook is used to enforce these restrictions,\n\
2965as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2966``normal'' call. The criteria for successful sibling call optimization\n\
2967may vary greatly between different architectures.",
2968 bool, (tree decl, tree exp),
2969 hook_bool_tree_tree_false)
2970
2971/* Establish appropriate back-end context for processing the function
2972 FNDECL. The argument might be NULL to indicate processing at top
2973 level, outside of any function scope. */
2974DEFHOOK
2975(set_current_function,
2976 "The compiler invokes this hook whenever it changes its current function\n\
2977context (@code{cfun}). You can define this function if\n\
2978the back end needs to perform any initialization or reset actions on a\n\
2979per-function basis. For example, it may be used to implement function\n\
2980attributes that affect register usage or code generation patterns.\n\
2981The argument @var{decl} is the declaration for the new function context,\n\
2982and may be null to indicate that the compiler has left a function context\n\
2983and is returning to processing at the top level.\n\
2984The default hook function does nothing.\n\
2985\n\
2986GCC sets @code{cfun} to a dummy function context during initialization of\n\
2987some parts of the back end. The hook function is not invoked in this\n\
2988situation; you need not worry about the hook being invoked recursively,\n\
2989or when the back end is in a partially-initialized state.\n\
2990@code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2991outside of any function scope.",
2992 void, (tree decl), hook_void_tree)
2993
2994/* True if EXP should be placed in a "small data" section. */
2995DEFHOOK
2996(in_small_data_p,
2997 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2998The default version of this hook always returns false.",
2999 bool, (const_tree exp),
3000 hook_bool_const_tree_false)
3001
3002/* True if EXP names an object for which name resolution must resolve
3003 to the current executable or shared library. */
3004DEFHOOK
3005(binds_local_p,
3006 "Returns true if @var{exp} names an object for which name resolution\n\
3007rules must resolve to the current ``module'' (dynamic shared library\n\
3008or executable image).\n\
3009\n\
3010The default version of this hook implements the name resolution rules\n\
3011for ELF, which has a looser model of global name binding than other\n\
3012currently supported object file formats.",
3013 bool, (const_tree exp),
3014 default_binds_local_p)
3015
3016/* Check if profiling code is before or after prologue. */
3017DEFHOOK
3018(profile_before_prologue,
3019 "It returns true if target wants profile code emitted before prologue.\n\n\
3020The default version of this hook use the target macro\n\
3021@code{PROFILE_BEFORE_PROLOGUE}.",
3022 bool, (void),
3023 default_profile_before_prologue)
3024
3025/* Return true if a leaf function should stay leaf even with profiling
3026 enabled. */
3027DEFHOOK
3028(keep_leaf_when_profiled,
3029 "This target hook returns true if the target wants the leaf flag for\
3030 the current function to stay true even if it calls mcount. This might\
3031 make sense for targets using the leaf flag only to determine whether a\
3032 stack frame needs to be generated or not and for which the call to\
3033 mcount is generated before the function prologue.",
3034 bool, (void),
3035 default_keep_leaf_when_profiled)
3036
3037/* Modify and return the identifier of a DECL's external name,
3038 originally identified by ID, as required by the target,
3039 (eg, append @nn to windows32 stdcall function names).
3040 The default is to return ID without modification. */
3041DEFHOOK
3042(mangle_decl_assembler_name,
3043 "Define this hook if you need to postprocess the assembler name generated\n\
3044by target-independent code. The @var{id} provided to this hook will be\n\
3045the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
3046or the mangled name of the @var{decl} in C++). The return value of the\n\
3047hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
3048your target system. The default implementation of this hook just\n\
3049returns the @var{id} provided.",
3050 tree, (tree decl, tree id),
3051 default_mangle_decl_assembler_name)
3052
3053/* Do something target-specific to record properties of the DECL into
3054 the associated SYMBOL_REF. */
3055DEFHOOK
3056(encode_section_info,
3057 "Define this hook if references to a symbol or a constant must be\n\
3058treated differently depending on something about the variable or\n\
3059function named by the symbol (such as what section it is in).\n\
3060\n\
3061The hook is executed immediately after rtl has been created for\n\
3062@var{decl}, which may be a variable or function declaration or\n\
3063an entry in the constant pool. In either case, @var{rtl} is the\n\
3064rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3065in this hook; that field may not have been initialized yet.\n\
3066\n\
3067In the case of a constant, it is safe to assume that the rtl is\n\
3068a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3069will also have this form, but that is not guaranteed. Global\n\
3070register variables, for instance, will have a @code{reg} for their\n\
3071rtl. (Normally the right thing to do with such unusual rtl is\n\
3072leave it alone.)\n\
3073\n\
3074The @var{new_decl_p} argument will be true if this is the first time\n\
3075that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3076be false for subsequent invocations, which will happen for duplicate\n\
3077declarations. Whether or not anything must be done for the duplicate\n\
3078declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3079@var{new_decl_p} is always true when the hook is called for a constant.\n\
3080\n\
3081@cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3082The usual thing for this hook to do is to record flags in the\n\
3083@code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3084Historically, the name string was modified if it was necessary to\n\
3085encode more than one bit of information, but this practice is now\n\
3086discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3087\n\
3088The default definition of this hook, @code{default_encode_section_info}\n\
3089in @file{varasm.c}, sets a number of commonly-useful bits in\n\
3090@code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3091before overriding it.",
3092 void, (tree decl, rtx rtl, int new_decl_p),
3093 default_encode_section_info)
3094
3095/* Undo the effects of encode_section_info on the symbol string. */
3096DEFHOOK
3097(strip_name_encoding,
3098 "Decode @var{name} and return the real name part, sans\n\
3099the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3100may have added.",
3101 const char *, (const char *name),
3102 default_strip_name_encoding)
3103
3104/* If shift optabs for MODE are known to always truncate the shift count,
3105 return the mask that they apply. Return 0 otherwise. */
3106DEFHOOK
3107(shift_truncation_mask,
3108 "This function describes how the standard shift patterns for @var{mode}\n\
3109deal with shifts by negative amounts or by more than the width of the mode.\n\
3110@xref{shift patterns}.\n\
3111\n\
3112On many machines, the shift patterns will apply a mask @var{m} to the\n\
3113shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3114equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3115this is true for mode @var{mode}, the function should return @var{m},\n\
3116otherwise it should return 0. A return value of 0 indicates that no\n\
3117particular behavior is guaranteed.\n\
3118\n\
3119Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3120@emph{not} apply to general shift rtxes; it applies only to instructions\n\
3121that are generated by the named shift patterns.\n\
3122\n\
3123The default implementation of this function returns\n\
3124@code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3125and 0 otherwise. This definition is always safe, but if\n\
3126@code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3127nevertheless truncate the shift count, you may get better code\n\
3128by overriding it.",
3129 unsigned HOST_WIDE_INT, (machine_mode mode),
3130 default_shift_truncation_mask)
3131
3132/* Return the number of divisions in the given MODE that should be present,
3133 so that it is profitable to turn the division into a multiplication by
3134 the reciprocal. */
3135DEFHOOK
3136(min_divisions_for_recip_mul,
3137 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3138divisions by the same divisor, by turning them into multiplications by\n\
3139the reciprocal. This target hook specifies the minimum number of divisions\n\
3140that should be there for GCC to perform the optimization for a variable\n\
3141of mode @var{mode}. The default implementation returns 3 if the machine\n\
3142has an instruction for the division, and 2 if it does not.",
3143 unsigned int, (machine_mode mode),
3144 default_min_divisions_for_recip_mul)
3145
3146DEFHOOK
3147(truly_noop_truncation,
3148 "This hook returns true if it is safe to ``convert'' a value of\n\
3149@var{inprec} bits to one of @var{outprec} bits (where @var{outprec} is\n\
3150smaller than @var{inprec}) by merely operating on it as if it had only\n\
3151@var{outprec} bits. The default returns true unconditionally, which\n\
3152is correct for most machines.\n\
3153\n\
3154If @code{TARGET_MODES_TIEABLE_P} returns false for a pair of modes,\n\
3155suboptimal code can result if this hook returns true for the corresponding\n\
3156mode sizes. Making this hook return false in such cases may improve things.",
3157 bool, (unsigned int outprec, unsigned int inprec),
3158 hook_bool_uint_uint_true)
3159
3160/* If the representation of integral MODE is such that values are
3161 always sign-extended to a wider mode MODE_REP then return
3162 SIGN_EXTEND. Return UNKNOWN otherwise. */
3163/* Note that the return type ought to be RTX_CODE, but that's not
3164 necessarily defined at this point. */
3165DEFHOOK
3166(mode_rep_extended,
3167 "The representation of an integral mode can be such that the values\n\
3168are always extended to a wider integral mode. Return\n\
3169@code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3170sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3171otherwise. (Currently, none of the targets use zero-extended\n\
3172representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3173@code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3174@code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3175@var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3176widest integral mode and currently we take advantage of this fact.)\n\
3177\n\
3178Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3179value even if the extension is not performed on certain hard registers\n\
3180as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3181@code{TARGET_CAN_CHANGE_MODE_CLASS} returns false.\n\
3182\n\
3183Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3184describe two related properties. If you define\n\
3185@code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3186to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3187extension.\n\
3188\n\
3189In order to enforce the representation of @code{mode},\n\
3190@code{TARGET_TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3191@code{mode}.",
3192 int, (scalar_int_mode mode, scalar_int_mode rep_mode),
3193 default_mode_rep_extended)
3194
3195/* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3196DEFHOOK
3197(valid_pointer_mode,
3198 "Define this to return nonzero if the port can handle pointers\n\
3199with machine mode @var{mode}. The default version of this\n\
3200hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3201 bool, (scalar_int_mode mode),
3202 default_valid_pointer_mode)
3203
3204/* Disambiguate with errno. */
3205DEFHOOK
3206(ref_may_alias_errno,
3207 "Define this to return nonzero if the memory reference @var{ref}\
3208 may alias with the system C library errno location. The default\
3209 version of this hook assumes the system C library errno location\
3210 is either a declaration of type int or accessed by dereferencing\
3211 a pointer to int.",
3212 bool, (struct ao_ref *ref),
3213 default_ref_may_alias_errno)
3214
3215/* Support for named address spaces. */
3216#undef HOOK_PREFIX
3217#define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3218HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3219
3220/* MODE to use for a pointer into another address space. */
3221DEFHOOK
3222(pointer_mode,
3223 "Define this to return the machine mode to use for pointers to\n\
3224@var{address_space} if the target supports named address spaces.\n\
3225The default version of this hook returns @code{ptr_mode}.",
3226 scalar_int_mode, (addr_space_t address_space),
3227 default_addr_space_pointer_mode)
3228
3229/* MODE to use for an address in another address space. */
3230DEFHOOK
3231(address_mode,
3232 "Define this to return the machine mode to use for addresses in\n\
3233@var{address_space} if the target supports named address spaces.\n\
3234The default version of this hook returns @code{Pmode}.",
3235 scalar_int_mode, (addr_space_t address_space),
3236 default_addr_space_address_mode)
3237
3238/* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3239 in another address space. */
3240DEFHOOK
3241(valid_pointer_mode,
3242 "Define this to return nonzero if the port can handle pointers\n\
3243with machine mode @var{mode} to address space @var{as}. This target\n\
3244hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3245except that it includes explicit named address space support. The default\n\
3246version of this hook returns true for the modes returned by either the\n\
3247@code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3248target hooks for the given address space.",
3249 bool, (scalar_int_mode mode, addr_space_t as),
3250 default_addr_space_valid_pointer_mode)
3251
3252/* True if an address is a valid memory address to a given named address
3253 space for a given mode. */
3254DEFHOOK
3255(legitimate_address_p,
3256 "Define this to return true if @var{exp} is a valid address for mode\n\
3257@var{mode} in the named address space @var{as}. The @var{strict}\n\
3258parameter says whether strict addressing is in effect after reload has\n\
3259finished. This target hook is the same as the\n\
3260@code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3261explicit named address space support.",
3262 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3263 default_addr_space_legitimate_address_p)
3264
3265/* Return an updated address to convert an invalid pointer to a named
3266 address space to a valid one. If NULL_RTX is returned use machine
3267 independent methods to make the address valid. */
3268DEFHOOK
3269(legitimize_address,
3270 "Define this to modify an invalid address @var{x} to be a valid address\n\
3271with mode @var{mode} in the named address space @var{as}. This target\n\
3272hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3273except that it includes explicit named address space support.",
3274 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3275 default_addr_space_legitimize_address)
3276
3277/* True if one named address space is a subset of another named address. */
3278DEFHOOK
3279(subset_p,
3280 "Define this to return whether the @var{subset} named address space is\n\
3281contained within the @var{superset} named address space. Pointers to\n\
3282a named address space that is a subset of another named address space\n\
3283will be converted automatically without a cast if used together in\n\
3284arithmetic operations. Pointers to a superset address space can be\n\
3285converted to pointers to a subset address space via explicit casts.",
3286 bool, (addr_space_t subset, addr_space_t superset),
3287 default_addr_space_subset_p)
3288
3289/* True if 0 is a valid address in the address space, or false if
3290 0 is a NULL in the address space. */
3291DEFHOOK
3292(zero_address_valid,
3293 "Define this to modify the default handling of address 0 for the\n\
3294address space. Return true if 0 should be considered a valid address.",
3295 bool, (addr_space_t as),
3296 default_addr_space_zero_address_valid)
3297
3298/* Function to convert an rtl expression from one address space to another. */
3299DEFHOOK
3300(convert,
3301 "Define this to convert the pointer expression represented by the RTL\n\
3302@var{op} with type @var{from_type} that points to a named address\n\
3303space to a new pointer expression with type @var{to_type} that points\n\
3304to a different named address space. When this hook it called, it is\n\
3305guaranteed that one of the two address spaces is a subset of the other,\n\
3306as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3307 rtx, (rtx op, tree from_type, tree to_type),
3308 default_addr_space_convert)
3309
3310/* Function to encode an address space into dwarf. */
3311DEFHOOK
3312(debug,
3313 "Define this to define how the address space is encoded in dwarf.\n\
3314The result is the value to be used with @code{DW_AT_address_class}.",
3315 int, (addr_space_t as),
3316 default_addr_space_debug)
3317
3318/* Function to emit custom diagnostic if an address space is used. */
3319DEFHOOK
3320(diagnose_usage,
3321 "Define this hook if the availability of an address space depends on\n\
3322command line options and some diagnostics should be printed when the\n\
3323address space is used. This hook is called during parsing and allows\n\
3324to emit a better diagnostic compared to the case where the address space\n\
3325was not registered with @code{c_register_addr_space}. @var{as} is\n\
3326the address space as registered with @code{c_register_addr_space}.\n\
3327@var{loc} is the location of the address space qualifier token.\n\
3328The default implementation does nothing.",
3329 void, (addr_space_t as, location_t loc),
3330 default_addr_space_diagnose_usage)
3331
3332HOOK_VECTOR_END (addr_space)
3333
3334#undef HOOK_PREFIX
3335#define HOOK_PREFIX "TARGET_"
3336
3337DEFHOOK
3338(static_rtx_alignment,
3339 "This hook returns the preferred alignment in bits for a\n\
3340statically-allocated rtx, such as a constant pool entry. @var{mode}\n\
3341is the mode of the rtx. The default implementation returns\n\
3342@samp{GET_MODE_ALIGNMENT (@var{mode})}.",
3343 HOST_WIDE_INT, (machine_mode mode),
3344 default_static_rtx_alignment)
3345
3346DEFHOOK
3347(constant_alignment,
3348 "This hook returns the alignment in bits of a constant that is being\n\
3349placed in memory. @var{constant} is the constant and @var{basic_align}\n\
3350is the alignment that the object would ordinarily have.\n\
3351\n\
3352The default definition just returns @var{basic_align}.\n\
3353\n\
3354The typical use of this hook is to increase alignment for string\n\
3355constants to be word aligned so that @code{strcpy} calls that copy\n\
3356constants can be done inline. The function\n\
3357@code{constant_alignment_word_strings} provides such a definition.",
3358 HOST_WIDE_INT, (const_tree constant, HOST_WIDE_INT basic_align),
3359 default_constant_alignment)
3360
3361/* True if MODE is valid for the target. By "valid", we mean able to
3362 be manipulated in non-trivial ways. In particular, this means all
3363 the arithmetic is supported. */
3364DEFHOOK
3365(scalar_mode_supported_p,
3366 "Define this to return nonzero if the port is prepared to handle\n\
3367insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3368considered supported, all the basic arithmetic and comparisons\n\
3369must work.\n\
3370\n\
3371The default version of this hook returns true for any mode\n\
3372required to handle the basic C types (as defined by the port).\n\
3373Included here are the double-word arithmetic supported by the\n\
3374code in @file{optabs.c}.",
3375 bool, (scalar_mode mode),
3376 default_scalar_mode_supported_p)
3377
3378/* Similarly for vector modes. "Supported" here is less strict. At
3379 least some operations are supported; need to check optabs or builtins
3380 for further details. */
3381DEFHOOK
3382(vector_mode_supported_p,
3383 "Define this to return nonzero if the port is prepared to handle\n\
3384insns involving vector mode @var{mode}. At the very least, it\n\
3385must have move patterns for this mode.",
3386 bool, (machine_mode mode),
3387 hook_bool_mode_false)
3388
3389DEFHOOK
3390(vector_alignment,
3391 "This hook can be used to define the alignment for a vector of type\n\
3392@var{type}, in order to comply with a platform ABI. The default is to\n\
3393require natural alignment for vector types. The alignment returned by\n\
3394this hook must be a power-of-two multiple of the default alignment of\n\
3395the vector element type.",
3396 HOST_WIDE_INT, (const_tree type),
3397 default_vector_alignment)
3398
3399/* True if we should try to use a scalar mode to represent an array,
3400 overriding the usual MAX_FIXED_MODE limit. */
3401DEFHOOK
3402(array_mode_supported_p,
3403 "Return true if GCC should try to use a scalar mode to store an array\n\
3404of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3405Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3406and allows GCC to use any defined integer mode.\n\
3407\n\
3408One use of this hook is to support vector load and store operations\n\
3409that operate on several homogeneous vectors. For example, ARM NEON\n\
3410has operations like:\n\
3411\n\
3412@smallexample\n\
3413int8x8x3_t vld3_s8 (const int8_t *)\n\
3414@end smallexample\n\
3415\n\
3416where the return type is defined as:\n\
3417\n\
3418@smallexample\n\
3419typedef struct int8x8x3_t\n\
3420@{\n\
3421 int8x8_t val[3];\n\
3422@} int8x8x3_t;\n\
3423@end smallexample\n\
3424\n\
3425If this hook allows @code{val} to have a scalar mode, then\n\
3426@code{int8x8x3_t} can have the same mode. GCC can then store\n\
3427@code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3428 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3429 hook_bool_mode_uhwi_false)
3430
3431DEFHOOK
3432(libgcc_floating_mode_supported_p,
3433 "Define this to return nonzero if libgcc provides support for the \n\
3434floating-point mode @var{mode}, which is known to pass \n\
3435@code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3436hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3437@code{XFmode} and @code{TFmode}, if such modes exist.",
3438 bool, (scalar_float_mode mode),
3439 default_libgcc_floating_mode_supported_p)
3440
3441DEFHOOK
3442(floatn_mode,
3443 "Define this to return the machine mode to use for the type \n\
3444@code{_Float@var{n}}, if @var{extended} is false, or the type \n\
3445@code{_Float@var{n}x}, if @var{extended} is true. If such a type is not\n\
3446supported, return @code{opt_scalar_float_mode ()}. The default version of\n\
3447this hook returns @code{SFmode} for @code{_Float32}, @code{DFmode} for\n\
3448@code{_Float64} and @code{_Float32x} and @code{TFmode} for \n\
3449@code{_Float128}, if those modes exist and satisfy the requirements for \n\
3450those types and pass @code{TARGET_SCALAR_MODE_SUPPORTED_P} and \n\
3451@code{TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P}; for @code{_Float64x}, it \n\
3452returns the first of @code{XFmode} and @code{TFmode} that exists and \n\
3453satisfies the same requirements; for other types, it returns \n\
3454@code{opt_scalar_float_mode ()}. The hook is only called for values\n\
3455of @var{n} and @var{extended} that are valid according to\n\
3456ISO/IEC TS 18661-3:2015; that is, @var{n} is one of 32, 64, 128, or,\n\
3457if @var{extended} is false, 16 or greater than 128 and a multiple of 32.",
3458 opt_scalar_float_mode, (int n, bool extended),
3459 default_floatn_mode)
3460
3461DEFHOOK
3462(floatn_builtin_p,
3463 "Define this to return true if the @code{_Float@var{n}} and\n\
3464@code{_Float@var{n}x} built-in functions should implicitly enable the\n\
3465built-in function without the @code{__builtin_} prefix in addition to the\n\
3466normal built-in function with the @code{__builtin_} prefix. The default is\n\
3467to only enable built-in functions without the @code{__builtin_} prefix for\n\
3468the GNU C langauge. In strict ANSI/ISO mode, the built-in function without\n\
3469the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is the\n\
3470@code{enum built_in_function} id of the function to be enabled.",
3471 bool, (int func),
3472 default_floatn_builtin_p)
3473
3474/* Compute cost of moving data from a register of class FROM to one of
3475 TO, using MODE. */
3476DEFHOOK
3477(register_move_cost,
3478 "This target hook should return the cost of moving data of mode @var{mode}\n\
3479from a register in class @var{from} to one in class @var{to}. The classes\n\
3480are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3481A value of 2 is the default; other values are interpreted relative to\n\
3482that.\n\
3483\n\
3484It is not required that the cost always equal 2 when @var{from} is the\n\
3485same as @var{to}; on some machines it is expensive to move between\n\
3486registers if they are not general registers.\n\
3487\n\
3488If reload sees an insn consisting of a single @code{set} between two\n\
3489hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3490classes returns a value of 2, reload does not check to ensure that the\n\
3491constraints of the insn are met. Setting a cost of other than 2 will\n\
3492allow reload to verify that the constraints are met. You should do this\n\
3493if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3494\n\
3495The default version of this function returns 2.",
3496 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3497 default_register_move_cost)
3498
3499/* Compute cost of moving registers to/from memory. */
3500/* ??? Documenting the argument types for this hook requires a GFDL
3501 license grant. Also, the documentation uses a different name for RCLASS. */
3502DEFHOOK
3503(memory_move_cost,
3504 "This target hook should return the cost of moving data of mode @var{mode}\n\
3505between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3506if the value is to be written to memory, @code{true} if it is to be read in.\n\
3507This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3508If moving between registers and memory is more expensive than between two\n\
3509registers, you should add this target hook to express the relative cost.\n\
3510\n\
3511If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3512the cost of copying via a secondary reload register, if one is\n\
3513needed. If your machine requires a secondary reload register to copy\n\
3514between memory and a register of @var{rclass} but the reload mechanism is\n\
3515more complex than copying via an intermediate, use this target hook to\n\
3516reflect the actual cost of the move.\n\
3517\n\
3518GCC defines the function @code{memory_move_secondary_cost} if\n\
3519secondary reloads are needed. It computes the costs due to copying via\n\
3520a secondary register. If your machine copies from memory using a\n\
3521secondary register in the conventional way but the default base value of\n\
35224 is not correct for your machine, use this target hook to add some other\n\
3523value to the result of that function. The arguments to that function\n\
3524are the same as to this target hook.",
3525 int, (machine_mode mode, reg_class_t rclass, bool in),
3526 default_memory_move_cost)
3527
3528DEFHOOK
3529(use_by_pieces_infrastructure_p,
3530 "GCC will attempt several strategies when asked to copy between\n\
3531two areas of memory, or to set, clear or store to memory, for example\n\
3532when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3533implements such memory operations as a sequence of load, store or move\n\
3534insns. Alternate strategies are to expand the\n\
3535@code{movmem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3536unit-by-unit, loop-based operations.\n\
3537\n\
3538This target hook should return true if, for a memory operation with a\n\
3539given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3540infrastructure is expected to result in better code generation.\n\
3541Both @var{size} and @var{alignment} are measured in terms of storage\n\
3542units.\n\
3543\n\
3544The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3545@code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\
3546@code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\
3547under consideration.\n\
3548\n\
3549The parameter @var{speed_p} is true if the code is currently being\n\
3550optimized for speed rather than size.\n\
3551\n\
3552Returning true for higher values of @var{size} can improve code generation\n\
3553for speed if the target does not provide an implementation of the\n\
3554@code{movmem} or @code{setmem} standard names, if the @code{movmem} or\n\
3555@code{setmem} implementation would be more expensive than a sequence of\n\
3556insns, or if the overhead of a library call would dominate that of\n\
3557the body of the memory operation.\n\
3558\n\
3559Returning true for higher values of @code{size} may also cause an increase\n\
3560in code size, for example where the number of insns emitted to perform a\n\
3561move would be greater than that of a library call.",
3562 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3563 enum by_pieces_operation op, bool speed_p),
3564 default_use_by_pieces_infrastructure_p)
3565
3566DEFHOOK
3567(compare_by_pieces_branch_ratio,
3568 "When expanding a block comparison in MODE, gcc can try to reduce the\n\
3569number of branches at the expense of more memory operations. This hook\n\
3570allows the target to override the default choice. It should return the\n\
3571factor by which branches should be reduced over the plain expansion with\n\
3572one comparison per @var{mode}-sized piece. A port can also prevent a\n\
3573particular mode from being used for block comparisons by returning a\n\
3574negative number from this hook.",
3575 int, (machine_mode mode),
3576 default_compare_by_pieces_branch_ratio)
3577
3578DEFHOOK
3579(slow_unaligned_access,
3580 "This hook returns true if memory accesses described by the\n\
3581@var{mode} and @var{alignment} parameters have a cost many times greater\n\
3582than aligned accesses, for example if they are emulated in a trap handler.\n\
3583This hook is invoked only for unaligned accesses, i.e. when\n\
3584@code{@var{alignment} < GET_MODE_ALIGNMENT (@var{mode})}.\n\
3585\n\
3586When this hook returns true, the compiler will act as if\n\
3587@code{STRICT_ALIGNMENT} were true when generating code for block\n\
3588moves. This can cause significantly more instructions to be produced.\n\
3589Therefore, do not make this hook return true if unaligned accesses only\n\
3590add a cycle or two to the time for a memory access.\n\
3591\n\
3592The hook must return true whenever @code{STRICT_ALIGNMENT} is true.\n\
3593The default implementation returns @code{STRICT_ALIGNMENT}.",
3594 bool, (machine_mode mode, unsigned int align),
3595 default_slow_unaligned_access)
3596
3597DEFHOOK
3598(optab_supported_p,
3599 "Return true if the optimizers should use optab @var{op} with\n\
3600modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\
3601The optab is known to have an associated @file{.md} instruction\n\
3602whose C condition is true. @var{mode2} is only meaningful for conversion\n\
3603optabs; for direct optabs it is a copy of @var{mode1}.\n\
3604\n\
3605For example, when called with @var{op} equal to @code{rint_optab} and\n\
3606@var{mode1} equal to @code{DFmode}, the hook should say whether the\n\
3607optimizers should use optab @code{rintdf2}.\n\
3608\n\
3609The default hook returns true for all inputs.",
3610 bool, (int op, machine_mode mode1, machine_mode mode2,
3611 optimization_type opt_type),
3612 default_optab_supported_p)
3613
3614/* True for MODE if the target expects that registers in this mode will
3615 be allocated to registers in a small register class. The compiler is
3616 allowed to use registers explicitly used in the rtl as spill registers
3617 but it should prevent extending the lifetime of these registers. */
3618DEFHOOK
3619(small_register_classes_for_mode_p,
3620 "Define this to return nonzero for machine modes for which the port has\n\
3621small register classes. If this target hook returns nonzero for a given\n\
3622@var{mode}, the compiler will try to minimize the lifetime of registers\n\
3623in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3624In this case, the hook is expected to return nonzero if it returns nonzero\n\
3625for any mode.\n\
3626\n\
3627On some machines, it is risky to let hard registers live across arbitrary\n\
3628insns. Typically, these machines have instructions that require values\n\
3629to be in specific registers (like an accumulator), and reload will fail\n\
3630if the required hard register is used for another purpose across such an\n\
3631insn.\n\
3632\n\
3633Passes before reload do not know which hard registers will be used\n\
3634in an instruction, but the machine modes of the registers set or used in\n\
3635the instruction are already known. And for some machines, register\n\
3636classes are small for, say, integer registers but not for floating point\n\
3637registers. For example, the AMD x86-64 architecture requires specific\n\
3638registers for the legacy x86 integer instructions, but there are many\n\
3639SSE registers for floating point operations. On such targets, a good\n\
3640strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3641machine modes but zero for the SSE register classes.\n\
3642\n\
3643The default version of this hook returns false for any mode. It is always\n\
3644safe to redefine this hook to return with a nonzero value. But if you\n\
3645unnecessarily define it, you will reduce the amount of optimizations\n\
3646that can be performed in some cases. If you do not define this hook\n\
3647to return a nonzero value when it is required, the compiler will run out\n\
3648of spill registers and print a fatal error message.",
3649 bool, (machine_mode mode),
3650 hook_bool_mode_false)
3651
3652/* Register number for a flags register. Only needs to be defined if the
3653 target is constrainted to use post-reload comparison elimination. */
3654DEFHOOKPOD
3655(flags_regnum,
3656 "If the target has a dedicated flags register, and it needs to use the\
3657 post-reload comparison elimination pass, then this value should be set\
3658 appropriately.",
3659 unsigned int, INVALID_REGNUM)
3660
3661/* Compute a (partial) cost for rtx X. Return true if the complete
3662 cost has been computed, and false if subexpressions should be
3663 scanned. In either case, *TOTAL contains the cost result. */
3664/* Note that OUTER_CODE ought to be RTX_CODE, but that's
3665 not necessarily defined at this point. */
3666DEFHOOK
3667(rtx_costs,
3668 "This target hook describes the relative costs of RTL expressions.\n\
3669\n\
3670The cost may depend on the precise form of the expression, which is\n\
3671available for examination in @var{x}, and the fact that @var{x} appears\n\
3672as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3673That is, the hook can assume that there is some rtx @var{y} such\n\
3674that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3675either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3676(b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3677\n\
3678@var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3679do not have a mode, the mode in which @var{x} is used.\n\
3680\n\
3681In implementing this hook, you can use the construct\n\
3682@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3683instructions.\n\
3684\n\
3685On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3686for the cost of the expression. The hook should modify this value as\n\
3687necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3688for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3689operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3690\n\
3691When optimizing for code size, i.e.@: when @code{speed} is\n\
3692false, this target hook should be used to estimate the relative\n\
3693size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3694\n\
3695The hook returns true when all subexpressions of @var{x} have been\n\
3696processed, and false when @code{rtx_cost} should recurse.",
3697 bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3698 hook_bool_rtx_mode_int_int_intp_bool_false)
3699
3700/* Compute the cost of X, used as an address. Never called with
3701 invalid addresses. */
3702DEFHOOK
3703(address_cost,
3704 "This hook computes the cost of an addressing mode that contains\n\
3705@var{address}. If not defined, the cost is computed from\n\
3706the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3707\n\
3708For most CISC machines, the default cost is a good approximation of the\n\
3709true cost of the addressing mode. However, on RISC machines, all\n\
3710instructions normally have the same length and execution time. Hence\n\
3711all addresses will have equal costs.\n\
3712\n\
3713In cases where more than one form of an address is known, the form with\n\
3714the lowest cost will be used. If multiple forms have the same, lowest,\n\
3715cost, the one that is the most complex will be used.\n\
3716\n\
3717For example, suppose an address that is equal to the sum of a register\n\
3718and a constant is used twice in the same basic block. When this macro\n\
3719is not defined, the address will be computed in a register and memory\n\
3720references will be indirect through that register. On machines where\n\
3721the cost of the addressing mode containing the sum is no higher than\n\
3722that of a simple indirect reference, this will produce an additional\n\
3723instruction and possibly require an additional register. Proper\n\
3724specification of this macro eliminates this overhead for such machines.\n\
3725\n\
3726This hook is never called with an invalid address.\n\
3727\n\
3728On machines where an address involving more than one register is as\n\
3729cheap as an address computation involving only one register, defining\n\
3730@code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3731be live over a region of code where only one would have been if\n\
3732@code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3733should be considered in the definition of this macro. Equivalent costs\n\
3734should probably only be given to addresses with different numbers of\n\
3735registers on machines with lots of registers.",
3736 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3737 default_address_cost)
3738
3739/* Compute a cost for INSN. */
3740DEFHOOK
3741(insn_cost,
3742 "This target hook describes the relative costs of RTL instructions.\n\
3743\n\
3744In implementing this hook, you can use the construct\n\
3745@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3746instructions.\n\
3747\n\
3748When optimizing for code size, i.e.@: when @code{speed} is\n\
3749false, this target hook should be used to estimate the relative\n\
3750size cost of an expression, again relative to @code{COSTS_N_INSNS}.",
3751 int, (rtx_insn *insn, bool speed), NULL)
3752
3753/* Give a cost, in RTX Costs units, for an edge. Like BRANCH_COST, but with
3754 well defined units. */
3755DEFHOOK
3756(max_noce_ifcvt_seq_cost,
3757 "This hook returns a value in the same units as @code{TARGET_RTX_COSTS},\n\
3758giving the maximum acceptable cost for a sequence generated by the RTL\n\
3759if-conversion pass when conditional execution is not available.\n\
3760The RTL if-conversion pass attempts to convert conditional operations\n\
3761that would require a branch to a series of unconditional operations and\n\
3762@code{mov@var{mode}cc} insns. This hook returns the maximum cost of the\n\
3763unconditional instructions and the @code{mov@var{mode}cc} insns.\n\
3764RTL if-conversion is cancelled if the cost of the converted sequence\n\
3765is greater than the value returned by this hook.\n\
3766\n\
3767@code{e} is the edge between the basic block containing the conditional\n\
3768branch to the basic block which would be executed if the condition\n\
3769were true.\n\
3770\n\
3771The default implementation of this hook uses the\n\
3772@code{max-rtl-if-conversion-[un]predictable} parameters if they are set,\n\
3773and uses a multiple of @code{BRANCH_COST} otherwise.",
3774unsigned int, (edge e),
3775default_max_noce_ifcvt_seq_cost)
3776
3777/* Return true if the given instruction sequence is a good candidate
3778 as a replacement for the if-convertible sequence. */
3779DEFHOOK
3780(noce_conversion_profitable_p,
3781 "This hook returns true if the instruction sequence @code{seq} is a good\n\
3782candidate as a replacement for the if-convertible sequence described in\n\
3783@code{if_info}.",
3784bool, (rtx_insn *seq, struct noce_if_info *if_info),
3785default_noce_conversion_profitable_p)
3786
3787/* Permit speculative instructions in delay slots during delayed-branch
3788 scheduling. */
3789DEFHOOK
3790(no_speculation_in_delay_slots_p,
3791 "This predicate controls the use of the eager delay slot filler to disallow\n\
3792speculatively executed instructions being placed in delay slots. Targets\n\
3793such as certain MIPS architectures possess both branches with and without\n\
3794delay slots. As the eager delay slot filler can decrease performance,\n\
3795disabling it is beneficial when ordinary branches are available. Use of\n\
3796delay slot branches filled using the basic filler is often still desirable\n\
3797as the delay slot can hide a pipeline bubble.", bool, (void),
3798 hook_bool_void_false)
3799
3800/* Return where to allocate pseudo for a given hard register initial value. */
3801DEFHOOK
3802(allocate_initial_value,
3803 "\n\
3804When the initial value of a hard register has been copied in a pseudo\n\
3805register, it is often not necessary to actually allocate another register\n\
3806to this pseudo register, because the original hard register or a stack slot\n\
3807it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3808is called at the start of register allocation once for each hard register\n\
3809that had its initial value copied by using\n\
3810@code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3811Possible values are @code{NULL_RTX}, if you don't want\n\
3812to do any special allocation, a @code{REG} rtx---that would typically be\n\
3813the hard register itself, if it is known not to be clobbered---or a\n\
3814@code{MEM}.\n\
3815If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3816it might decide to use another register anyways.\n\
3817You may use @code{current_function_is_leaf} or \n\
3818@code{REG_N_SETS} in the hook to determine if the hard\n\
3819register in question will not be clobbered.\n\
3820The default value of this hook is @code{NULL}, which disables any special\n\
3821allocation.",
3822 rtx, (rtx hard_reg), NULL)
3823
3824/* Return nonzero if evaluating UNSPEC X might cause a trap.
3825 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3826DEFHOOK
3827(unspec_may_trap_p,
3828 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3829@code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3830this hook to enhance precision of analysis for @code{unspec} and\n\
3831@code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3832to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3833passed along.",
3834 int, (const_rtx x, unsigned flags),
3835 default_unspec_may_trap_p)
3836
3837/* Given a register, this hook should return a parallel of registers
3838 to represent where to find the register pieces. Define this hook
3839 if the register and its mode are represented in Dwarf in
3840 non-contiguous locations, or if the register should be
3841 represented in more than one register in Dwarf. Otherwise, this
3842 hook should return NULL_RTX. */
3843DEFHOOK
3844(dwarf_register_span,
3845 "Given a register, this hook should return a parallel of registers to\n\
3846represent where to find the register pieces. Define this hook if the\n\
3847register and its mode are represented in Dwarf in non-contiguous\n\
3848locations, or if the register should be represented in more than one\n\
3849register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3850If not defined, the default is to return @code{NULL_RTX}.",
3851 rtx, (rtx reg),
3852 hook_rtx_rtx_null)
3853
3854/* Given a register return the mode of the corresponding DWARF frame
3855 register. */
3856DEFHOOK
3857(dwarf_frame_reg_mode,
3858 "Given a register, this hook should return the mode which the\n\
3859corresponding Dwarf frame register should have. This is normally\n\
3860used to return a smaller mode than the raw mode to prevent call\n\
3861clobbered parts of a register altering the frame register size",
3862 machine_mode, (int regno),
3863 default_dwarf_frame_reg_mode)
3864
3865/* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3866 entries not corresponding directly to registers below
3867 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3868 code, given the address of the table. */
3869DEFHOOK
3870(init_dwarf_reg_sizes_extra,
3871 "If some registers are represented in Dwarf-2 unwind information in\n\
3872multiple pieces, define this hook to fill in information about the\n\
3873sizes of those pieces in the table used by the unwinder at runtime.\n\
3874It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3875filling in a single size corresponding to each hard register;\n\
3876@var{address} is the address of the table.",
3877 void, (tree address),
3878 hook_void_tree)
3879
3880/* Fetch the fixed register(s) which hold condition codes, for
3881 targets where it makes sense to look for duplicate assignments to
3882 the condition codes. This should return true if there is such a
3883 register, false otherwise. The arguments should be set to the
3884 fixed register numbers. Up to two condition code registers are
3885 supported. If there is only one for this target, the int pointed
3886 at by the second argument should be set to -1. */
3887DEFHOOK
3888(fixed_condition_code_regs,
3889 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3890register rather than a pseudo-register to hold condition codes, the\n\
3891regular CSE passes are often not able to identify cases in which the\n\
3892hard register is set to a common value. Use this hook to enable a\n\
3893small pass which optimizes such cases. This hook should return true\n\
3894to enable this pass, and it should set the integers to which its\n\
3895arguments point to the hard register numbers used for condition codes.\n\
3896When there is only one such register, as is true on most systems, the\n\
3897integer pointed to by @var{p2} should be set to\n\
3898@code{INVALID_REGNUM}.\n\
3899\n\
3900The default version of this hook returns false.",
3901 bool, (unsigned int *p1, unsigned int *p2),
3902 hook_bool_uintp_uintp_false)
3903
3904/* If two condition code modes are compatible, return a condition
3905 code mode which is compatible with both, such that a comparison
3906 done in the returned mode will work for both of the original
3907 modes. If the condition code modes are not compatible, return
3908 VOIDmode. */
3909DEFHOOK
3910(cc_modes_compatible,
3911 "On targets which use multiple condition code modes in class\n\
3912@code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3913validly done in more than one mode. On such a system, define this\n\
3914target hook to take two mode arguments and to return a mode in which\n\
3915both comparisons may be validly done. If there is no such mode,\n\
3916return @code{VOIDmode}.\n\
3917\n\
3918The default version of this hook checks whether the modes are the\n\
3919same. If they are, it returns that mode. If they are different, it\n\
3920returns @code{VOIDmode}.",
3921 machine_mode, (machine_mode m1, machine_mode m2),
3922 default_cc_modes_compatible)
3923
3924/* Do machine-dependent code transformations. Called just before
3925 delayed-branch scheduling. */
3926DEFHOOK
3927(machine_dependent_reorg,
3928 "If non-null, this hook performs a target-specific pass over the\n\
3929instruction stream. The compiler will run it at all optimization levels,\n\
3930just before the point at which it normally does delayed-branch scheduling.\n\
3931\n\
3932The exact purpose of the hook varies from target to target. Some use\n\
3933it to do transformations that are necessary for correctness, such as\n\
3934laying out in-function constant pools or avoiding hardware hazards.\n\
3935Others use it as an opportunity to do some machine-dependent optimizations.\n\
3936\n\
3937You need not implement the hook if it has nothing to do. The default\n\
3938definition is null.",
3939 void, (void), NULL)
3940
3941/* Create the __builtin_va_list type. */
3942DEFHOOK
3943(build_builtin_va_list,
3944 "This hook returns a type node for @code{va_list} for the target.\n\
3945The default version of the hook returns @code{void*}.",
3946 tree, (void),
3947 std_build_builtin_va_list)
3948
3949/* Enumerate the va list variants. */
3950DEFHOOK
3951(enum_va_list_p,
3952 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3953to iterate through the target specific builtin types for va_list. The\n\
3954variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3955to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3956variable.\n\
3957The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3958this macro and are set to the name of the va_list builtin type and its\n\
3959internal type.\n\
3960If the return value of this macro is zero, then there is no more element.\n\
3961Otherwise the @var{IDX} should be increased for the next call of this\n\
3962macro to iterate through all types.",
3963 int, (int idx, const char **pname, tree *ptree),
3964 NULL)
3965
3966/* Get the cfun/fndecl calling abi __builtin_va_list type. */
3967DEFHOOK
3968(fn_abi_va_list,
3969 "This hook returns the va_list type of the calling convention specified by\n\
3970@var{fndecl}.\n\
3971The default version of this hook returns @code{va_list_type_node}.",
3972 tree, (tree fndecl),
3973 std_fn_abi_va_list)
3974
3975/* Get the __builtin_va_list type dependent on input type. */
3976DEFHOOK
3977(canonical_va_list_type,
3978 "This hook returns the va_list type of the calling convention specified by the\n\
3979type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3980@code{NULL_TREE}.",
3981 tree, (tree type),
3982 std_canonical_va_list_type)
3983
3984/* ??? Documenting this hook requires a GFDL license grant. */
3985DEFHOOK_UNDOC
3986(expand_builtin_va_start,
3987"Expand the @code{__builtin_va_start} builtin.",
3988 void, (tree valist, rtx nextarg), NULL)
3989
3990/* Gimplifies a VA_ARG_EXPR. */
3991DEFHOOK
3992(gimplify_va_arg_expr,
3993 "This hook performs target-specific gimplification of\n\
3994@code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
3995arguments to @code{va_arg}; the latter two are as in\n\
3996@code{gimplify.c:gimplify_expr}.",
3997 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3998 std_gimplify_va_arg_expr)
3999
4000/* Validity-checking routines for PCH files, target-specific.
4001 get_pch_validity returns a pointer to the data to be stored,
4002 and stores the size in its argument. pch_valid_p gets the same
4003 information back and returns NULL if the PCH is valid,
4004 or an error message if not. */
4005DEFHOOK
4006(get_pch_validity,
4007 "This hook returns a pointer to the data needed by\n\
4008@code{TARGET_PCH_VALID_P} and sets\n\
4009@samp{*@var{sz}} to the size of the data in bytes.",
4010 void *, (size_t *sz),
4011 default_get_pch_validity)
4012
4013DEFHOOK
4014(pch_valid_p,
4015 "This hook checks whether the options used to create a PCH file are\n\
4016compatible with the current settings. It returns @code{NULL}\n\
4017if so and a suitable error message if not. Error messages will\n\
4018be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
4019\n\
4020@var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
4021when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
4022It's safe to assume that the data was created by the same version of the\n\
4023compiler, so no format checking is needed.\n\
4024\n\
4025The default definition of @code{default_pch_valid_p} should be\n\
4026suitable for most targets.",
4027 const char *, (const void *data, size_t sz),
4028 default_pch_valid_p)
4029
4030DEFHOOK
4031(prepare_pch_save,
4032 "Called before writing out a PCH file. If the target has some\n\
4033garbage-collected data that needs to be in a particular state on PCH loads,\n\
4034it can use this hook to enforce that state. Very few targets need\n\
4035to do anything here.",
4036 void, (void),
4037 hook_void_void)
4038
4039/* If nonnull, this function checks whether a PCH file with the
4040 given set of target flags can be used. It returns NULL if so,
4041 otherwise it returns an error message. */
4042DEFHOOK
4043(check_pch_target_flags,
4044 "If this hook is nonnull, the default implementation of\n\
4045@code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
4046of @code{target_flags}. @var{pch_flags} specifies the value that\n\
4047@code{target_flags} had when the PCH file was created. The return\n\
4048value is the same as for @code{TARGET_PCH_VALID_P}.",
4049 const char *, (int pch_flags), NULL)
4050
4051/* True if the compiler should give an enum type only as many
4052 bytes as it takes to represent the range of possible values of
4053 that type. */
4054DEFHOOK
4055(default_short_enums,
4056 "This target hook should return true if the compiler should give an\n\
4057@code{enum} type only as many bytes as it takes to represent the range\n\
4058of possible values of that type. It should return false if all\n\
4059@code{enum} types should be allocated like @code{int}.\n\
4060\n\
4061The default is to return false.",
4062 bool, (void),
4063 hook_bool_void_false)
4064
4065/* This target hook returns an rtx that is used to store the address
4066 of the current frame into the built-in setjmp buffer. */
4067DEFHOOK
4068(builtin_setjmp_frame_value,
4069 "This target hook should return an rtx that is used to store\n\
4070the address of the current frame into the built in @code{setjmp} buffer.\n\
4071The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
4072machines. One reason you may need to define this target hook is if\n\
4073@code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
4074 rtx, (void),
4075 default_builtin_setjmp_frame_value)
4076
4077/* This target hook should manipulate the outputs, inputs, constraints,
4078 and clobbers the port wishes for pre-processing the asm. */
4079DEFHOOK
4080(md_asm_adjust,
4081 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
4082@var{clobbered_regs} for any hard regs the port wishes to automatically\n\
4083clobber for an asm. The @var{outputs} and @var{inputs} may be inspected\n\
4084to avoid clobbering a register that is already used by the asm.\n\
4085\n\
4086It may modify the @var{outputs}, @var{inputs}, and @var{constraints}\n\
4087as necessary for other pre-processing. In this case the return value is\n\
4088a sequence of insns to emit after the asm.",
4089 rtx_insn *,
4090 (vec<rtx>& outputs, vec<rtx>& inputs, vec<const char *>& constraints,
4091 vec<rtx>& clobbers, HARD_REG_SET& clobbered_regs),
4092 NULL)
4093
4094/* This target hook allows the backend to specify a calling convention
4095 in the debug information. This function actually returns an
4096 enum dwarf_calling_convention, but because of forward declarations
4097 and not wanting to include dwarf2.h everywhere target.h is included
4098 the function is being declared as an int. */
4099DEFHOOK
4100(dwarf_calling_convention,
4101 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
4102be emitted for each function. Instead of an integer return the enum\n\
4103value for the @code{DW_CC_} tag.",
4104 int, (const_tree function),
4105 hook_int_const_tree_0)
4106
4107/* This target hook allows the backend to emit frame-related insns that
4108 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
4109 engine will invoke it on insns of the form
4110 (set (reg) (unspec [...] UNSPEC_INDEX))
4111 and
4112 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
4113 to let the backend emit the call frame instructions. */
4114DEFHOOK
4115(dwarf_handle_frame_unspec,
4116 "This target hook allows the backend to emit frame-related insns that\n\
4117contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
4118info engine will invoke it on insns of the form\n\
4119@smallexample\n\
4120(set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
4121@end smallexample\n\
4122and\n\
4123@smallexample\n\
4124(set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
4125@end smallexample\n\
4126to let the backend emit the call frame instructions. @var{label} is\n\
4127the CFI label attached to the insn, @var{pattern} is the pattern of\n\
4128the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
4129 void, (const char *label, rtx pattern, int index), NULL)
4130
4131/* ??? Documenting this hook requires a GFDL license grant. */
4132DEFHOOK_UNDOC
4133(stdarg_optimize_hook,
4134"Perform architecture specific checking of statements gimplified\
4135 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
4136 the statement doesn't need to be checked for @code{va_list} references.",
4137 bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
4138
4139/* This target hook allows the operating system to override the DECL
4140 that represents the external variable that contains the stack
4141 protection guard variable. The type of this DECL is ptr_type_node. */
4142DEFHOOK
4143(stack_protect_guard,
4144 "This hook returns a @code{DECL} node for the external variable to use\n\
4145for the stack protection guard. This variable is initialized by the\n\
4146runtime to some random value and is used to initialize the guard value\n\
4147that is placed at the top of the local stack frame. The type of this\n\
4148variable must be @code{ptr_type_node}.\n\
4149\n\
4150The default version of this hook creates a variable called\n\
4151@samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
4152 tree, (void),
4153 default_stack_protect_guard)
4154
4155/* This target hook allows the operating system to override the CALL_EXPR
4156 that is invoked when a check vs the guard variable fails. */
4157DEFHOOK
4158(stack_protect_fail,
4159 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
4160stack protect guard variable has been modified. This expression should\n\
4161involve a call to a @code{noreturn} function.\n\
4162\n\
4163The default version of this hook invokes a function called\n\
4164@samp{__stack_chk_fail}, taking no arguments. This function is\n\
4165normally defined in @file{libgcc2.c}.",
4166 tree, (void),
4167 default_external_stack_protect_fail)
4168
4169/* This target hook allows the operating system to disable the default stack
4170 protector runtime support. */
4171DEFHOOK
4172(stack_protect_runtime_enabled_p,
4173 "Returns true if the target wants GCC's default stack protect runtime support,\
4174 otherwise return false. The default implementation always returns true.",
4175 bool, (void),
4176 hook_bool_void_true)
4177
4178DEFHOOK
4179(can_use_doloop_p,
4180 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
4181and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
4182exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
4183the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
4184the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
4185contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
4186loop is only entered from the top.\n\
4187\n\
4188This hook is only used if @code{doloop_end} is available. The default\n\
4189implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
4190if the loop must be the innermost, and if there are no other restrictions.",
4191 bool, (const widest_int &iterations, const widest_int &iterations_max,
4192 unsigned int loop_depth, bool entered_at_top),
4193 hook_bool_wint_wint_uint_bool_true)
4194
4195/* Returns NULL if target supports the insn within a doloop block,
4196 otherwise it returns an error message. */
4197DEFHOOK
4198(invalid_within_doloop,
4199 "\n\
4200Take an instruction in @var{insn} and return NULL if it is valid within a\n\
4201low-overhead loop, otherwise return a string explaining why doloop\n\
4202could not be applied.\n\
4203\n\
4204Many targets use special registers for low-overhead looping. For any\n\
4205instruction that clobbers these this function should return a string indicating\n\
4206the reason why the doloop could not be applied.\n\
4207By default, the RTL loop optimizer does not use a present doloop pattern for\n\
4208loops containing function calls or branch on table instructions.",
4209 const char *, (const rtx_insn *insn),
4210 default_invalid_within_doloop)
4211
4212/* Returns true for a legitimate combined insn. */
4213DEFHOOK
4214(legitimate_combined_insn,
4215"Take an instruction in @var{insn} and return @code{false} if the instruction\
4216 is not appropriate as a combination of two or more instructions. The\
4217 default is to accept all instructions.",
4218 bool, (rtx_insn *insn),
4219 hook_bool_rtx_insn_true)
4220
4221DEFHOOK
4222(valid_dllimport_attribute_p,
4223"@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
4224 specified. Use this hook if the target needs to add extra validation\
4225 checks to @code{handle_dll_attribute}.",
4226 bool, (const_tree decl),
4227 hook_bool_const_tree_true)
4228
4229/* If non-zero, align constant anchors in CSE to a multiple of this
4230 value. */
4231DEFHOOKPOD
4232(const_anchor,
4233 "On some architectures it can take multiple instructions to synthesize\n\
4234a constant. If there is another constant already in a register that\n\
4235is close enough in value then it is preferable that the new constant\n\
4236is computed from this register using immediate addition or\n\
4237subtraction. We accomplish this through CSE. Besides the value of\n\
4238the constant we also add a lower and an upper constant anchor to the\n\
4239available expressions. These are then queried when encountering new\n\
4240constants. The anchors are computed by rounding the constant up and\n\
4241down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
4242@code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
4243accepted by immediate-add plus one. We currently assume that the\n\
4244value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
4245MIPS, where add-immediate takes a 16-bit signed value,\n\
4246@code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
4247is zero, which disables this optimization.",
4248 unsigned HOST_WIDE_INT, 0)
4249
4250/* Defines, which target-dependent bits (upper 16) are used by port */
4251DEFHOOK
4252(memmodel_check,
4253 "Validate target specific memory model mask bits. When NULL no target specific\n\
4254memory model bits are allowed.",
4255 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4256
4257/* Defines an offset bitwise ored into shifted address to get corresponding
4258 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4259 supported by the target. */
4260DEFHOOK
4261(asan_shadow_offset,
4262 "Return the offset bitwise ored into shifted address to get corresponding\n\
4263Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4264supported by the target.",
4265 unsigned HOST_WIDE_INT, (void),
4266 NULL)
4267
4268/* Functions relating to calls - argument passing, returns, etc. */
4269/* Members of struct call have no special macro prefix. */
4270HOOK_VECTOR (TARGET_CALLS, calls)
4271
4272DEFHOOK
4273(promote_function_mode,
4274 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4275function return values. The target hook should return the new mode\n\
4276and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4277change signedness. This function is called only for scalar @emph{or\n\
4278pointer} types.\n\
4279\n\
4280@var{for_return} allows to distinguish the promotion of arguments and\n\
4281return values. If it is @code{1}, a return value is being promoted and\n\
4282@code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4283If it is @code{2}, the returned mode should be that of the register in\n\
4284which an incoming parameter is copied, or the outgoing result is computed;\n\
4285then the hook should return the same mode as @code{promote_mode}, though\n\
4286the signedness may be different.\n\
4287\n\
4288@var{type} can be NULL when promoting function arguments of libcalls.\n\
4289\n\
4290The default is to not promote arguments and return values. You can\n\
4291also define the hook to @code{default_promote_function_mode_always_promote}\n\
4292if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4293 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4294 const_tree funtype, int for_return),
4295 default_promote_function_mode)
4296
4297DEFHOOK
4298(promote_prototypes,
4299 "This target hook returns @code{true} if an argument declared in a\n\
4300prototype as an integral type smaller than @code{int} should actually be\n\
4301passed as an @code{int}. In addition to avoiding errors in certain\n\
4302cases of mismatch, it also makes for better code on certain machines.\n\
4303The default is to not promote prototypes.",
4304 bool, (const_tree fntype),
4305 hook_bool_const_tree_false)
4306
4307DEFHOOK
4308(struct_value_rtx,
4309 "This target hook should return the location of the structure value\n\
4310address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4311passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4312be @code{NULL}, for libcalls. You do not need to define this target\n\
4313hook if the address is always passed as an ``invisible'' first\n\
4314argument.\n\
4315\n\
4316On some architectures the place where the structure value address\n\
4317is found by the called function is not the same place that the\n\
4318caller put it. This can be due to register windows, or it could\n\
4319be because the function prologue moves it to a different place.\n\
4320@var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4321the context of the called function, and @code{0} in the context of\n\
4322the caller.\n\
4323\n\
4324If @var{incoming} is nonzero and the address is to be found on the\n\
4325stack, return a @code{mem} which refers to the frame pointer. If\n\
4326@var{incoming} is @code{2}, the result is being used to fetch the\n\
4327structure value address at the beginning of a function. If you need\n\
4328to emit adjusting code, you should do it at this point.",
4329 rtx, (tree fndecl, int incoming),
4330 hook_rtx_tree_int_null)
4331
4332DEFHOOKPOD
4333(omit_struct_return_reg,
4334 "Normally, when a function returns a structure by memory, the address\n\
4335is passed as an invisible pointer argument, but the compiler also\n\
4336arranges to return the address from the function like it would a normal\n\
4337pointer return value. Define this to true if that behavior is\n\
4338undesirable on your target.",
4339 bool, false)
4340
4341DEFHOOK
4342(return_in_memory,
4343 "This target hook should return a nonzero value to say to return the\n\
4344function value in memory, just as large structures are always returned.\n\
4345Here @var{type} will be the data type of the value, and @var{fntype}\n\
4346will be the type of the function doing the returning, or @code{NULL} for\n\
4347libcalls.\n\
4348\n\
4349Note that values of mode @code{BLKmode} must be explicitly handled\n\
4350by this function. Also, the option @option{-fpcc-struct-return}\n\
4351takes effect regardless of this macro. On most systems, it is\n\
4352possible to leave the hook undefined; this causes a default\n\
4353definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4354values, and 0 otherwise.\n\
4355\n\
4356Do not use this hook to indicate that structures and unions should always\n\
4357be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4358to indicate this.",
4359 bool, (const_tree type, const_tree fntype),
4360 default_return_in_memory)
4361
4362DEFHOOK
4363(return_in_msb,
4364 "This hook should return true if values of type @var{type} are returned\n\
4365at the most significant end of a register (in other words, if they are\n\
4366padded at the least significant end). You can assume that @var{type}\n\
4367is returned in a register; the caller is required to check this.\n\
4368\n\
4369Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4370be able to hold the complete return value. For example, if a 1-, 2-\n\
4371or 3-byte structure is returned at the most significant end of a\n\
43724-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4373@code{SImode} rtx.",
4374 bool, (const_tree type),
4375 hook_bool_const_tree_false)
4376
4377/* Return true if a parameter must be passed by reference. TYPE may
4378 be null if this is a libcall. CA may be null if this query is
4379 from __builtin_va_arg. */
4380DEFHOOK
4381(pass_by_reference,
4382 "This target hook should return @code{true} if an argument at the\n\
4383position indicated by @var{cum} should be passed by reference. This\n\
4384predicate is queried after target independent reasons for being\n\
4385passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
4386\n\
4387If the hook returns true, a copy of that argument is made in memory and a\n\
4388pointer to the argument is passed instead of the argument itself.\n\
4389The pointer is passed in whatever way is appropriate for passing a pointer\n\
4390to that type.",
4391 bool,
4392 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4393 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4394
4395DEFHOOK
4396(expand_builtin_saveregs,
4397 "If defined, this hook produces the machine-specific code for a call to\n\
4398@code{__builtin_saveregs}. This code will be moved to the very\n\
4399beginning of the function, before any parameter access are made. The\n\
4400return value of this function should be an RTX that contains the value\n\
4401to use as the return of @code{__builtin_saveregs}.",
4402 rtx, (void),
4403 default_expand_builtin_saveregs)
4404
4405/* Returns pretend_argument_size. */
4406DEFHOOK
4407(setup_incoming_varargs,
4408 "This target hook offers an alternative to using\n\
4409@code{__builtin_saveregs} and defining the hook\n\
4410@code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4411register arguments into the stack so that all the arguments appear to\n\
4412have been passed consecutively on the stack. Once this is done, you can\n\
4413use the standard implementation of varargs that works for machines that\n\
4414pass all their arguments on the stack.\n\
4415\n\
4416The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4417structure, containing the values that are obtained after processing the\n\
4418named arguments. The arguments @var{mode} and @var{type} describe the\n\
4419last named argument---its machine mode and its data type as a tree node.\n\
4420\n\
4421The target hook should do two things: first, push onto the stack all the\n\
4422argument registers @emph{not} used for the named arguments, and second,\n\
4423store the size of the data thus pushed into the @code{int}-valued\n\
4424variable pointed to by @var{pretend_args_size}. The value that you\n\
4425store here will serve as additional offset for setting up the stack\n\
4426frame.\n\
4427\n\
4428Because you must generate code to push the anonymous arguments at\n\
4429compile time without knowing their data types,\n\
4430@code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4431have just a single category of argument register and use it uniformly\n\
4432for all data types.\n\
4433\n\
4434If the argument @var{second_time} is nonzero, it means that the\n\
4435arguments of the function are being analyzed for the second time. This\n\
4436happens for an inline function, which is not actually compiled until the\n\
4437end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4438not generate any instructions in this case.",
4439 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4440 int *pretend_args_size, int second_time),
4441 default_setup_incoming_varargs)
4442
4443DEFHOOK
4444(load_bounds_for_arg,
4445 "This hook is used by expand pass to emit insn to load bounds of\n\
4446@var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4447bounds of @var{arg} are not passed in register. If @var{slot} is a\n\
4448memory, then bounds are loaded as for regular pointer loaded from\n\
4449memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4450constant holding number of the target dependent special slot which\n\
4451should be used to obtain bounds. Hook returns RTX holding loaded bounds.",
4452 rtx, (rtx slot, rtx arg, rtx slot_no),
4453 default_load_bounds_for_arg)
4454
4455DEFHOOK
4456(store_bounds_for_arg,
4457 "This hook is used by expand pass to emit insns to store @var{bounds} of\n\
4458@var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4459@var{bounds} of @var{arg} are not passed in register. If @var{slot} is a\n\
4460memory, then @var{bounds} are stored as for regular pointer stored in\n\
4461memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4462constant holding number of the target dependent special slot which\n\
4463should be used to store @var{bounds}.",
4464 void, (rtx arg, rtx slot, rtx bounds, rtx slot_no),
4465 default_store_bounds_for_arg)
4466
4467DEFHOOK
4468(load_returned_bounds,
4469 "This hook is used by expand pass to emit insn to load bounds\n\
4470returned by function call in @var{slot}. Hook returns RTX holding\n\
4471loaded bounds.",
4472 rtx, (rtx slot),
4473 default_load_returned_bounds)
4474
4475DEFHOOK
4476(store_returned_bounds,
4477 "This hook is used by expand pass to emit insn to store @var{bounds}\n\
4478returned by function call into @var{slot}.",
4479 void, (rtx slot, rtx bounds),
4480 default_store_returned_bounds)
4481
4482DEFHOOK
4483(setup_incoming_vararg_bounds,
4484 "Use it to store bounds for anonymous register arguments stored\n\
4485into the stack. Arguments meaning is similar to\n\
4486@code{TARGET_SETUP_INCOMING_VARARGS}.",
4487 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4488 int *pretend_args_size, int second_time),
4489 default_setup_incoming_vararg_bounds)
4490
4491DEFHOOK
4492(call_args,
4493 "While generating RTL for a function call, this target hook is invoked once\n\
4494for each argument passed to the function, either a register returned by\n\
4495@code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4496before the point where argument registers are stored. The type of the\n\
4497function to be called is also passed as the second argument; it is\n\
4498@code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4499invoked just after the code to copy the return reg has been emitted.\n\
4500This functionality can be used to perform special setup of call argument\n\
4501registers if a target needs it.\n\
4502For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4503passed instead of an argument register.\n\
4504Most ports do not need to implement anything for this hook.",
4505 void, (rtx, tree),
4506 hook_void_rtx_tree)
4507
4508DEFHOOK
4509(end_call_args,
4510 "This target hook is invoked while generating RTL for a function call,\n\
4511just after the point where the return reg is copied into a pseudo. It\n\
4512signals that all the call argument and return registers for the just\n\
4513emitted call are now no longer in use.\n\
4514Most ports do not need to implement anything for this hook.",
4515 void, (void),
4516 hook_void_void)
4517
4518DEFHOOK
4519(strict_argument_naming,
4520 "Define this hook to return @code{true} if the location where a function\n\
4521argument is passed depends on whether or not it is a named argument.\n\
4522\n\
4523This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4524is set for varargs and stdarg functions. If this hook returns\n\
4525@code{true}, the @var{named} argument is always true for named\n\
4526arguments, and false for unnamed arguments. If it returns @code{false},\n\
4527but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4528then all arguments are treated as named. Otherwise, all named arguments\n\
4529except the last are treated as named.\n\
4530\n\
4531You need not define this hook if it always returns @code{false}.",
4532 bool, (cumulative_args_t ca),
4533 hook_bool_CUMULATIVE_ARGS_false)
4534
4535/* Returns true if we should use
4536 targetm.calls.setup_incoming_varargs() and/or
4537 targetm.calls.strict_argument_naming(). */
4538DEFHOOK
4539(pretend_outgoing_varargs_named,
4540 "If you need to conditionally change ABIs so that one works with\n\
4541@code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4542@code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4543defined, then define this hook to return @code{true} if\n\
4544@code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4545Otherwise, you should not define this hook.",
4546 bool, (cumulative_args_t ca),
4547 default_pretend_outgoing_varargs_named)
4548
4549/* Given a complex type T, return true if a parameter of type T
4550 should be passed as two scalars. */
4551DEFHOOK
4552(split_complex_arg,
4553 "This hook should return true if parameter of type @var{type} are passed\n\
4554as two scalar parameters. By default, GCC will attempt to pack complex\n\
4555arguments into the target's word size. Some ABIs require complex arguments\n\
4556to be split and treated as their individual components. For example, on\n\
4557AIX64, complex floats should be passed in a pair of floating point\n\
4558registers, even though a complex float would fit in one 64-bit floating\n\
4559point register.\n\
4560\n\
4561The default value of this hook is @code{NULL}, which is treated as always\n\
4562false.",
4563 bool, (const_tree type), NULL)
4564
4565/* Return true if type T, mode MODE, may not be passed in registers,
4566 but must be passed on the stack. */
4567/* ??? This predicate should be applied strictly after pass-by-reference.
4568 Need audit to verify that this is the case. */
4569DEFHOOK
4570(must_pass_in_stack,
4571 "This target hook should return @code{true} if we should not pass @var{type}\n\
4572solely in registers. The file @file{expr.h} defines a\n\
4573definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4574documentation.",
4575 bool, (machine_mode mode, const_tree type),
4576 must_pass_in_stack_var_size_or_pad)
4577
4578/* Return true if type TYPE, mode MODE, which is passed by reference,
4579 should have the object copy generated by the callee rather than
4580 the caller. It is never called for TYPE requiring constructors. */
4581DEFHOOK
4582(callee_copies,
4583 "The function argument described by the parameters to this hook is\n\
4584known to be passed by reference. The hook should return true if the\n\
4585function argument should be copied by the callee instead of copied\n\
4586by the caller.\n\
4587\n\
4588For any argument for which the hook returns true, if it can be\n\
4589determined that the argument is not modified, then a copy need\n\
4590not be generated.\n\
4591\n\
4592The default version of this hook always returns false.",
4593 bool,
4594 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4595 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4596
4597/* Return zero for arguments passed entirely on the stack or entirely
4598 in registers. If passed in both, return the number of bytes passed
4599 in registers; the balance is therefore passed on the stack. */
4600DEFHOOK
4601(arg_partial_bytes,
4602 "This target hook returns the number of bytes at the beginning of an\n\
4603argument that must be put in registers. The value must be zero for\n\
4604arguments that are passed entirely in registers or that are entirely\n\
4605pushed on the stack.\n\
4606\n\
4607On some machines, certain arguments must be passed partially in\n\
4608registers and partially in memory. On these machines, typically the\n\
4609first few words of arguments are passed in registers, and the rest\n\
4610on the stack. If a multi-word argument (a @code{double} or a\n\
4611structure) crosses that boundary, its first few words must be passed\n\
4612in registers and the rest must be pushed. This macro tells the\n\
4613compiler when this occurs, and how many bytes should go in registers.\n\
4614\n\
4615@code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4616register to be used by the caller for this argument; likewise\n\
4617@code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4618 int, (cumulative_args_t cum, machine_mode mode, tree type, bool named),
4619 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
4620
4621/* Update the state in CA to advance past an argument in the
4622 argument list. The values MODE, TYPE, and NAMED describe that
4623 argument. */
4624DEFHOOK
4625(function_arg_advance,
4626 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4627advance past an argument in the argument list. The values @var{mode},\n\
4628@var{type} and @var{named} describe that argument. Once this is done,\n\
4629the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4630argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4631\n\
4632This hook need not do anything if the argument in question was passed\n\
4633on the stack. The compiler knows how to track the amount of stack space\n\
4634used for arguments without any special help.",
4635 void,
4636 (cumulative_args_t ca, machine_mode mode, const_tree type, bool named),
4637 default_function_arg_advance)
4638
4639DEFHOOK
4640(function_arg_offset,
4641 "This hook returns the number of bytes to add to the offset of an\n\
4642argument of type @var{type} and mode @var{mode} when passed in memory.\n\
4643This is needed for the SPU, which passes @code{char} and @code{short}\n\
4644arguments in the preferred slot that is in the middle of the quad word\n\
4645instead of starting at the top. The default implementation returns 0.",
4646 HOST_WIDE_INT, (machine_mode mode, const_tree type),
4647 default_function_arg_offset)
4648
4649DEFHOOK
4650(function_arg_padding,
4651 "This hook determines whether, and in which direction, to pad out\n\
4652an argument of mode @var{mode} and type @var{type}. It returns\n\
4653@code{PAD_UPWARD} to insert padding above the argument, @code{PAD_DOWNWARD}\n\
4654to insert padding below the argument, or @code{PAD_NONE} to inhibit padding.\n\
4655\n\
4656The @emph{amount} of padding is not controlled by this hook, but by\n\
4657@code{TARGET_FUNCTION_ARG_ROUND_BOUNDARY}. It is always just enough\n\
4658to reach the next multiple of that boundary.\n\
4659\n\
4660This hook has a default definition that is right for most systems.\n\
4661For little-endian machines, the default is to pad upward. For\n\
4662big-endian machines, the default is to pad downward for an argument of\n\
4663constant size shorter than an @code{int}, and upward otherwise.",
4664 pad_direction, (machine_mode mode, const_tree type),
4665 default_function_arg_padding)
4666
4667/* Return zero if the argument described by the state of CA should
4668 be placed on a stack, or a hard register in which to store the
4669 argument. The values MODE, TYPE, and NAMED describe that
4670 argument. */
4671DEFHOOK
4672(function_arg,
4673 "Return an RTX indicating whether a function argument is passed in a\n\
4674register and if so, which register.\n\
4675\n\
4676The arguments are @var{ca}, which summarizes all the previous\n\
4677arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
4678the data type of the argument as a tree node or 0 if that is not known\n\
4679(which happens for C support library functions); and @var{named},\n\
4680which is @code{true} for an ordinary argument and @code{false} for\n\
4681nameless arguments that correspond to @samp{@dots{}} in the called\n\
4682function's prototype. @var{type} can be an incomplete type if a\n\
4683syntax error has previously occurred.\n\
4684\n\
4685The return value is usually either a @code{reg} RTX for the hard\n\
4686register in which to pass the argument, or zero to pass the argument\n\
4687on the stack.\n\
4688\n\
4689The return value can be a @code{const_int} which means argument is\n\
4690passed in a target specific slot with specified number. Target hooks\n\
4691should be used to store or load argument in such case. See\n\
4692@code{TARGET_STORE_BOUNDS_FOR_ARG} and @code{TARGET_LOAD_BOUNDS_FOR_ARG}\n\
4693for more information.\n\
4694\n\
4695The value of the expression can also be a @code{parallel} RTX@. This is\n\
4696used when an argument is passed in multiple locations. The mode of the\n\
4697@code{parallel} should be the mode of the entire argument. The\n\
4698@code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4699describes where part of the argument is passed. In each\n\
4700@code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4701register in which to pass this part of the argument, and the mode of the\n\
4702register RTX indicates how large this part of the argument is. The\n\
4703second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4704the offset in bytes into the entire argument of where this part starts.\n\
4705As a special exception the first @code{expr_list} in the @code{parallel}\n\
4706RTX may have a first operand of zero. This indicates that the entire\n\
4707argument is also stored on the stack.\n\
4708\n\
4709The last time this hook is called, it is called with @code{MODE ==\n\
4710VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4711pattern as operands 2 and 3 respectively.\n\
4712\n\
4713@cindex @file{stdarg.h} and register arguments\n\
4714The usual way to make the ISO library @file{stdarg.h} work on a\n\
4715machine where some arguments are usually passed in registers, is to\n\
4716cause nameless arguments to be passed on the stack instead. This is\n\
4717done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4718@var{named} is @code{false}.\n\
4719\n\
4720@cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4721@cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4722You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4723in the definition of this macro to determine if this argument is of a\n\
4724type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4725is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4726argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4727defined, the argument will be computed in the stack and then loaded into\n\
4728a register.",
4729 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4730 bool named),
4731 default_function_arg)
4732
4733DEFHOOK
4734(function_incoming_arg,
4735 "Define this hook if the caller and callee on the target have different\n\
4736views of where arguments are passed. Also define this hook if there are\n\
4737functions that are never directly called, but are invoked by the hardware\n\
4738and which have nonstandard calling conventions.\n\
4739\n\
4740In this case @code{TARGET_FUNCTION_ARG} computes the register in\n\
4741which the caller passes the value, and\n\
4742@code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4743fashion to tell the function being called where the arguments will\n\
4744arrive.\n\
4745\n\
4746@code{TARGET_FUNCTION_INCOMING_ARG} can also return arbitrary address\n\
4747computation using hard register, which can be forced into a register,\n\
4748so that it can be used to pass special arguments.\n\
4749\n\
4750If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4751@code{TARGET_FUNCTION_ARG} serves both purposes.",
4752 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4753 bool named),
4754 default_function_incoming_arg)
4755
4756DEFHOOK
4757(function_arg_boundary,
4758 "This hook returns the alignment boundary, in bits, of an argument\n\
4759with the specified mode and type. The default hook returns\n\
4760@code{PARM_BOUNDARY} for all arguments.",
4761 unsigned int, (machine_mode mode, const_tree type),
4762 default_function_arg_boundary)
4763
4764DEFHOOK
4765(function_arg_round_boundary,
4766 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4767which is the default value for this hook. You can define this hook to\n\
4768return a different value if an argument size must be rounded to a larger\n\
4769value.",
4770 unsigned int, (machine_mode mode, const_tree type),
4771 default_function_arg_round_boundary)
4772
4773/* Return the diagnostic message string if function without a prototype
4774 is not allowed for this 'val' argument; NULL otherwise. */
4775DEFHOOK
4776(invalid_arg_for_unprototyped_fn,
4777 "If defined, this macro returns the diagnostic message when it is\n\
4778illegal to pass argument @var{val} to function @var{funcdecl}\n\
4779with prototype @var{typelist}.",
4780 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4781 hook_invalid_arg_for_unprototyped_fn)
4782
4783/* Return an rtx for the return value location of the function
4784 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4785DEFHOOK
4786(function_value,
4787 "\n\
4788Define this to return an RTX representing the place where a function\n\
4789returns or receives a value of data type @var{ret_type}, a tree node\n\
4790representing a data type. @var{fn_decl_or_type} is a tree node\n\
4791representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4792function being called. If @var{outgoing} is false, the hook should\n\
4793compute the register in which the caller will see the return value.\n\
4794Otherwise, the hook should return an RTX representing the place where\n\
4795a function returns a value.\n\
4796\n\
4797On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4798(Actually, on most machines, scalar values are returned in the same\n\
4799place regardless of mode.) The value of the expression is usually a\n\
4800@code{reg} RTX for the hard register where the return value is stored.\n\
4801The value can also be a @code{parallel} RTX, if the return value is in\n\
4802multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4803@code{parallel} form. Note that the callee will populate every\n\
4804location specified in the @code{parallel}, but if the first element of\n\
4805the @code{parallel} contains the whole return value, callers will use\n\
4806that element as the canonical location and ignore the others. The m68k\n\
4807port uses this type of @code{parallel} to return pointers in both\n\
4808@samp{%a0} (the canonical location) and @samp{%d0}.\n\
4809\n\
4810If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
4811the same promotion rules specified in @code{PROMOTE_MODE} if\n\
4812@var{valtype} is a scalar type.\n\
4813\n\
4814If the precise function being called is known, @var{func} is a tree\n\
4815node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
4816pointer. This makes it possible to use a different value-returning\n\
4817convention for specific functions when all their calls are\n\
4818known.\n\
4819\n\
4820Some target machines have ``register windows'' so that the register in\n\
4821which a function returns its value is not the same as the one in which\n\
4822the caller sees the value. For such machines, you should return\n\
4823different RTX depending on @var{outgoing}.\n\
4824\n\
4825@code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
4826aggregate data types, because these are returned in another way. See\n\
4827@code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
4828 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4829 default_function_value)
4830
4831/* Return the rtx for bounds of returned pointer. */
4832DEFHOOK
4833(chkp_function_value_bounds,
4834 "Define this to return an RTX representing the place where a function\n\
4835returns bounds for returned pointers. Arguments meaning is similar to\n\
4836@code{TARGET_FUNCTION_VALUE}.",
4837 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4838 default_chkp_function_value_bounds)
4839
4840/* Return the rtx for the result of a libcall of mode MODE,
4841 calling the function FN_NAME. */
4842DEFHOOK
4843(libcall_value,
4844 "Define this hook if the back-end needs to know the name of the libcall\n\
4845function in order to determine where the result should be returned.\n\
4846\n\
4847The mode of the result is given by @var{mode} and the name of the called\n\
4848library function is given by @var{fun}. The hook should return an RTX\n\
4849representing the place where the library function result will be returned.\n\
4850\n\
4851If this hook is not defined, then LIBCALL_VALUE will be used.",
4852 rtx, (machine_mode mode, const_rtx fun),
4853 default_libcall_value)
4854
4855/* Return true if REGNO is a possible register number for
4856 a function value as seen by the caller. */
4857DEFHOOK
4858(function_value_regno_p,
4859 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4860register in which the values of called function may come back.\n\
4861\n\
4862A register whose use for returning values is limited to serving as the\n\
4863second of a pair (for a value of type @code{double}, say) need not be\n\
4864recognized by this target hook.\n\
4865\n\
4866If the machine has register windows, so that the caller and the called\n\
4867function use different registers for the return value, this target hook\n\
4868should recognize only the caller's register numbers.\n\
4869\n\
4870If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4871 bool, (const unsigned int regno),
4872 default_function_value_regno_p)
4873
4874/* ??? Documenting this hook requires a GFDL license grant. */
4875DEFHOOK_UNDOC
4876(internal_arg_pointer,
4877"Return an rtx for the argument pointer incoming to the\
4878 current function.",
4879 rtx, (void),
4880 default_internal_arg_pointer)
4881
4882/* Update the current function stack boundary if needed. */
4883DEFHOOK
4884(update_stack_boundary,
4885 "Define this macro to update the current function stack boundary if\n\
4886necessary.",
4887 void, (void), NULL)
4888
4889/* Handle stack alignment and return an rtx for Dynamic Realign
4890 Argument Pointer if necessary. */
4891DEFHOOK
4892(get_drap_rtx,
4893 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4894different argument pointer register is needed to access the function's\n\
4895argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
4896is needed.",
4897 rtx, (void), NULL)
4898
4899/* Return true if all function parameters should be spilled to the
4900 stack. */
4901DEFHOOK
4902(allocate_stack_slots_for_args,
4903 "When optimization is disabled, this hook indicates whether or not\n\
4904arguments should be allocated to stack slots. Normally, GCC allocates\n\
4905stacks slots for arguments when not optimizing in order to make\n\
4906debugging easier. However, when a function is declared with\n\
4907@code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4908cannot safely move arguments from the registers in which they are passed\n\
4909to the stack. Therefore, this hook should return true in general, but\n\
4910false for naked functions. The default implementation always returns true.",
4911 bool, (void),
4912 hook_bool_void_true)
4913
4914/* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
4915 is true, then it should be for the callee; otherwise for the caller. */
4916DEFHOOK
4917(static_chain,
4918 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4919targets that may use different static chain locations for different\n\
4920nested functions. This may be required if the target has function\n\
4921attributes that affect the calling conventions of the function and\n\
4922those calling conventions use different static chain locations.\n\
4923\n\
4924The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4925\n\
4926If the static chain is passed in memory, this hook should be used to\n\
4927provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4928Often the @code{mem} expression as seen by the caller will be at an offset\n\
4929from the stack pointer and the @code{mem} expression as seen by the callee\n\
4930will be at an offset from the frame pointer.\n\
4931@findex stack_pointer_rtx\n\
4932@findex frame_pointer_rtx\n\
4933@findex arg_pointer_rtx\n\
4934The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4935@code{arg_pointer_rtx} will have been initialized and should be used\n\
4936to refer to those items.",
4937 rtx, (const_tree fndecl_or_type, bool incoming_p),
4938 default_static_chain)
4939
4940/* Fill in the trampoline at MEM with a call to FNDECL and a
4941 static chain value of CHAIN. */
4942DEFHOOK
4943(trampoline_init,
4944 "This hook is called to initialize a trampoline.\n\
4945@var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4946is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4947RTX for the static chain value that should be passed to the function\n\
4948when it is called.\n\
4949\n\
4950If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4951first thing this hook should do is emit a block move into @var{m_tramp}\n\
4952from the memory block returned by @code{assemble_trampoline_template}.\n\
4953Note that the block move need only cover the constant parts of the\n\
4954trampoline. If the target isolates the variable parts of the trampoline\n\
4955to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4956\n\
4957If the target requires any other actions, such as flushing caches or\n\
4958enabling stack execution, these actions should be performed after\n\
4959initializing the trampoline proper.",
4960 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4961 default_trampoline_init)
4962
4963/* Adjust the address of the trampoline in a target-specific way. */
4964DEFHOOK
4965(trampoline_adjust_address,
4966 "This hook should perform any machine-specific adjustment in\n\
4967the address of the trampoline. Its argument contains the address of the\n\
4968memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
4969the address to be used for a function call should be different from the\n\
4970address at which the template was stored, the different address should\n\
4971be returned; otherwise @var{addr} should be returned unchanged.\n\
4972If this hook is not defined, @var{addr} will be used for function calls.",
4973 rtx, (rtx addr), NULL)
4974
4975DEFHOOKPOD
4976(custom_function_descriptors,
4977 "This hook should be defined to a power of 2 if the target will benefit\n\
4978from the use of custom descriptors for nested functions instead of the\n\
4979standard trampolines. Such descriptors are created at run time on the\n\
4980stack and made up of data only, but they are non-standard so the generated\n\
4981code must be prepared to deal with them. This hook should be defined to 0\n\
4982if the target uses function descriptors for its standard calling sequence,\n\
4983like for example HP-PA or IA-64. Using descriptors for nested functions\n\
4984eliminates the need for trampolines that reside on the stack and require\n\
4985it to be made executable.\n\
4986\n\
4987The value of the macro is used to parameterize the run-time identification\n\
4988scheme implemented to distinguish descriptors from function addresses: it\n\
4989gives the number of bytes by which their address is misaligned compared\n\
4990with function addresses. The value of 1 will generally work, unless it is\n\
4991already reserved by the target for another purpose, like for example on ARM.",\
4992 int, -1)
4993
4994/* Return the number of bytes of its own arguments that a function
4995 pops on returning, or 0 if the function pops no arguments and the
4996 caller must therefore pop them all after the function returns. */
4997/* ??? tm.texi has no types for the parameters. */
4998DEFHOOK
4999(return_pops_args,
5000 "This target hook returns the number of bytes of its own arguments that\n\
5001a function pops on returning, or 0 if the function pops no arguments\n\
5002and the caller must therefore pop them all after the function returns.\n\
5003\n\
5004@var{fundecl} is a C variable whose value is a tree node that describes\n\
5005the function in question. Normally it is a node of type\n\
5006@code{FUNCTION_DECL} that describes the declaration of the function.\n\
5007From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
5008\n\
5009@var{funtype} is a C variable whose value is a tree node that\n\
5010describes the function in question. Normally it is a node of type\n\
5011@code{FUNCTION_TYPE} that describes the data type of the function.\n\
5012From this it is possible to obtain the data types of the value and\n\
5013arguments (if known).\n\
5014\n\
5015When a call to a library function is being considered, @var{fundecl}\n\
5016will contain an identifier node for the library function. Thus, if\n\
5017you need to distinguish among various library functions, you can do so\n\
5018by their names. Note that ``library function'' in this context means\n\
5019a function used to perform arithmetic, whose name is known specially\n\
5020in the compiler and was not mentioned in the C code being compiled.\n\
5021\n\
5022@var{size} is the number of bytes of arguments passed on the\n\
5023stack. If a variable number of bytes is passed, it is zero, and\n\
5024argument popping will always be the responsibility of the calling function.\n\
5025\n\
5026On the VAX, all functions always pop their arguments, so the definition\n\
5027of this macro is @var{size}. On the 68000, using the standard\n\
5028calling convention, no functions pop their arguments, so the value of\n\
5029the macro is always 0 in this case. But an alternative calling\n\
5030convention is available in which functions that take a fixed number of\n\
5031arguments pop them but other functions (such as @code{printf}) pop\n\
5032nothing (the caller pops all). When this convention is in use,\n\
5033@var{funtype} is examined to determine whether a function takes a fixed\n\
5034number of arguments.",
5035 int, (tree fundecl, tree funtype, int size),
5036 default_return_pops_args)
5037
5038/* Return a mode wide enough to copy any function value that might be
5039 returned. */
5040DEFHOOK
5041(get_raw_result_mode,
5042 "This target hook returns the mode to be used when accessing raw return\
5043 registers in @code{__builtin_return}. Define this macro if the value\
5044 in @var{reg_raw_mode} is not correct.",
5045 fixed_size_mode, (int regno),
5046 default_get_reg_raw_mode)
5047
5048/* Return a mode wide enough to copy any argument value that might be
5049 passed. */
5050DEFHOOK
5051(get_raw_arg_mode,
5052 "This target hook returns the mode to be used when accessing raw argument\
5053 registers in @code{__builtin_apply_args}. Define this macro if the value\
5054 in @var{reg_raw_mode} is not correct.",
5055 fixed_size_mode, (int regno),
5056 default_get_reg_raw_mode)
5057
5058/* Return true if a type is an empty record. */
5059DEFHOOK
5060(empty_record_p,
5061 "This target hook returns true if the type is an empty record. The default\n\
5062is to return @code{false}.",
5063 bool, (const_tree type),
5064 hook_bool_const_tree_false)
5065
5066/* Warn about the change in empty class parameter passing ABI. */
5067DEFHOOK
5068(warn_parameter_passing_abi,
5069 "This target hook warns about the change in empty class parameter passing\n\
5070ABI.",
5071 void, (cumulative_args_t ca, tree type),
5072 hook_void_CUMULATIVE_ARGS_tree)
5073
5074HOOK_VECTOR_END (calls)
5075
5076DEFHOOK
5077(use_pseudo_pic_reg,
5078 "This hook should return 1 in case pseudo register should be created\n\
5079for pic_offset_table_rtx during function expand.",
5080 bool, (void),
5081 hook_bool_void_false)
5082
5083DEFHOOK
5084(init_pic_reg,
5085 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
5086This hook is called at the start of register allocation.",
5087 void, (void),
5088 hook_void_void)
5089
5090/* Return the diagnostic message string if conversion from FROMTYPE
5091 to TOTYPE is not allowed, NULL otherwise. */
5092DEFHOOK
5093(invalid_conversion,
5094 "If defined, this macro returns the diagnostic message when it is\n\
5095invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
5096if validity should be determined by the front end.",
5097 const char *, (const_tree fromtype, const_tree totype),
5098 hook_constcharptr_const_tree_const_tree_null)
5099
5100/* Return the diagnostic message string if the unary operation OP is
5101 not permitted on TYPE, NULL otherwise. */
5102DEFHOOK
5103(invalid_unary_op,
5104 "If defined, this macro returns the diagnostic message when it is\n\
5105invalid to apply operation @var{op} (where unary plus is denoted by\n\
5106@code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
5107if validity should be determined by the front end.",
5108 const char *, (int op, const_tree type),
5109 hook_constcharptr_int_const_tree_null)
5110
5111/* Return the diagnostic message string if the binary operation OP
5112 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
5113DEFHOOK
5114(invalid_binary_op,
5115 "If defined, this macro returns the diagnostic message when it is\n\
5116invalid to apply operation @var{op} to operands of types @var{type1}\n\
5117and @var{type2}, or @code{NULL} if validity should be determined by\n\
5118the front end.",
5119 const char *, (int op, const_tree type1, const_tree type2),
5120 hook_constcharptr_int_const_tree_const_tree_null)
5121
5122/* If values of TYPE are promoted to some other type when used in
5123 expressions (analogous to the integer promotions), return that type,
5124 or NULL_TREE otherwise. */
5125DEFHOOK
5126(promoted_type,
5127 "If defined, this target hook returns the type to which values of\n\
5128@var{type} should be promoted when they appear in expressions,\n\
5129analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
5130front end's normal promotion rules. This hook is useful when there are\n\
5131target-specific types with special promotion rules.\n\
5132This is currently used only by the C and C++ front ends.",
5133 tree, (const_tree type),
5134 hook_tree_const_tree_null)
5135
5136/* Convert EXPR to TYPE, if target-specific types with special conversion
5137 rules are involved. Return the converted expression, or NULL to apply
5138 the standard conversion rules. */
5139DEFHOOK
5140(convert_to_type,
5141 "If defined, this hook returns the result of converting @var{expr} to\n\
5142@var{type}. It should return the converted expression,\n\
5143or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
5144This hook is useful when there are target-specific types with special\n\
5145conversion rules.\n\
5146This is currently used only by the C and C++ front ends.",
5147 tree, (tree type, tree expr),
5148 hook_tree_tree_tree_null)
5149
5150DEFHOOK
5151(can_change_mode_class,
5152 "This hook returns true if it is possible to bitcast values held in\n\
5153registers of class @var{rclass} from mode @var{from} to mode @var{to}\n\
5154and if doing so preserves the low-order bits that are common to both modes.\n\
5155The result is only meaningful if @var{rclass} has registers that can hold\n\
5156both @code{from} and @code{to}. The default implementation returns true.\n\
5157\n\
5158As an example of when such bitcasting is invalid, loading 32-bit integer or\n\
5159floating-point objects into floating-point registers on Alpha extends them\n\
5160to 64 bits. Therefore loading a 64-bit object and then storing it as a\n\
516132-bit object does not store the low-order 32 bits, as would be the case\n\
5162for a normal register. Therefore, @file{alpha.h} defines\n\
5163@code{TARGET_CAN_CHANGE_MODE_CLASS} to return:\n\
5164\n\
5165@smallexample\n\
5166(GET_MODE_SIZE (from) == GET_MODE_SIZE (to)\n\
5167 || !reg_classes_intersect_p (FLOAT_REGS, rclass))\n\
5168@end smallexample\n\
5169\n\
5170Even if storing from a register in mode @var{to} would be valid,\n\
5171if both @var{from} and @code{raw_reg_mode} for @var{rclass} are wider\n\
5172than @code{word_mode}, then we must prevent @var{to} narrowing the\n\
5173mode. This happens when the middle-end assumes that it can load\n\
5174or store pieces of an @var{N}-word pseudo, and that the pseudo will\n\
5175eventually be allocated to @var{N} @code{word_mode} hard registers.\n\
5176Failure to prevent this kind of mode change will result in the\n\
5177entire @code{raw_reg_mode} being modified instead of the partial\n\
5178value that the middle-end intended.",
5179 bool, (machine_mode from, machine_mode to, reg_class_t rclass),
5180 hook_bool_mode_mode_reg_class_t_true)
5181
5182/* Change pseudo allocno class calculated by IRA. */
5183DEFHOOK
5184(ira_change_pseudo_allocno_class,
5185 "A target hook which can change allocno class for given pseudo from\n\
5186 allocno and best class calculated by IRA.\n\
5187 \n\
5188 The default version of this target hook always returns given class.",
5189 reg_class_t, (int, reg_class_t, reg_class_t),
5190 default_ira_change_pseudo_allocno_class)
5191
5192/* Return true if we use LRA instead of reload. */
5193DEFHOOK
5194(lra_p,
5195 "A target hook which returns true if we use LRA instead of reload pass.\
5196 \
5197 The default version of this target hook returns true. New ports\
5198 should use LRA, and existing ports are encouraged to convert.",
5199 bool, (void),
5200 default_lra_p)
5201
5202/* Return register priority of given hard regno for the current target. */
5203DEFHOOK
5204(register_priority,
5205 "A target hook which returns the register priority number to which the\
5206 register @var{hard_regno} belongs to. The bigger the number, the\
5207 more preferable the hard register usage (when all other conditions are\
5208 the same). This hook can be used to prefer some hard register over\
5209 others in LRA. For example, some x86-64 register usage needs\
5210 additional prefix which makes instructions longer. The hook can\
5211 return lower priority number for such registers make them less favorable\
5212 and as result making the generated code smaller.\
5213 \
5214 The default version of this target hook returns always zero.",
5215 int, (int),
5216 default_register_priority)
5217
5218/* Return true if we need register usage leveling. */
5219DEFHOOK
5220(register_usage_leveling_p,
5221 "A target hook which returns true if we need register usage leveling.\
5222 That means if a few hard registers are equally good for the\
5223 assignment, we choose the least used hard register. The register\
5224 usage leveling may be profitable for some targets. Don't use the\
5225 usage leveling for targets with conditional execution or targets\
5226 with big register files as it hurts if-conversion and cross-jumping\
5227 optimizations.\
5228 \
5229 The default version of this target hook returns always false.",
5230 bool, (void),
5231 default_register_usage_leveling_p)
5232
5233/* Return true if maximal address displacement can be different. */
5234DEFHOOK
5235(different_addr_displacement_p,
5236 "A target hook which returns true if an address with the same structure\
5237 can have different maximal legitimate displacement. For example, the\
5238 displacement can depend on memory mode or on operand combinations in\
5239 the insn.\
5240 \
5241 The default version of this target hook returns always false.",
5242 bool, (void),
5243 default_different_addr_displacement_p)
5244
5245/* Determine class for spilling pseudos of given mode into registers
5246 instead of memory. */
5247DEFHOOK
5248(spill_class,
5249 "This hook defines a class of registers which could be used for spilling\
5250 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
5251 should be used. Not defining this hook is equivalent to returning\
5252 @code{NO_REGS} for all inputs.",
5253 reg_class_t, (reg_class_t, machine_mode),
5254 NULL)
5255
5256/* Determine an additional allocno class. */
5257DEFHOOK
5258(additional_allocno_class_p,
5259 "This hook should return @code{true} if given class of registers should\
5260 be an allocno class in any way. Usually RA uses only one register\
5261 class from all classes containing the same register set. In some\
5262 complicated cases, you need to have two or more such classes as\
5263 allocno ones for RA correct work. Not defining this hook is\
5264 equivalent to returning @code{false} for all inputs.",
5265 bool, (reg_class_t),
5266 hook_bool_reg_class_t_false)
5267
5268DEFHOOK
5269(cstore_mode,
5270 "This hook defines the machine mode to use for the boolean result of\
5271 conditional store patterns. The ICODE argument is the instruction code\
5272 for the cstore being performed. Not definiting this hook is the same\
5273 as accepting the mode encoded into operand 0 of the cstore expander\
5274 patterns.",
5275 scalar_int_mode, (enum insn_code icode),
5276 default_cstore_mode)
5277
5278/* This target hook allows the backend to compute the register pressure
5279 classes to use. */
5280DEFHOOK
5281(compute_pressure_classes,
5282 "A target hook which lets a backend compute the set of pressure classes to\
5283 be used by those optimization passes which take register pressure into\
5284 account, as opposed to letting IRA compute them. It returns the number of\
5285 register classes stored in the array @var{pressure_classes}.",
5286 int, (enum reg_class *pressure_classes), NULL)
5287
5288/* True if a structure, union or array with MODE containing FIELD should
5289 be accessed using BLKmode. */
5290DEFHOOK
5291(member_type_forces_blk,
5292 "Return true if a structure, union or array containing @var{field} should\n\
5293be accessed using @code{BLKMODE}.\n\
5294\n\
5295If @var{field} is the only field in the structure, @var{mode} is its\n\
5296mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
5297case where structures of one field would require the structure's mode to\n\
5298retain the field's mode.\n\
5299\n\
5300Normally, this is not needed.",
5301 bool, (const_tree field, machine_mode mode),
5302 default_member_type_forces_blk)
5303
5304/* See tree-ssa-math-opts.c:divmod_candidate_p for conditions
5305 that gate the divod transform. */
5306DEFHOOK
5307(expand_divmod_libfunc,
5308 "Define this hook for enabling divmod transform if the port does not have\n\
5309hardware divmod insn but defines target-specific divmod libfuncs.",
5310 void, (rtx libfunc, machine_mode mode, rtx op0, rtx op1, rtx *quot, rtx *rem),
5311 NULL)
5312
5313/* Return the class for a secondary reload, and fill in extra information. */
5314DEFHOOK
5315(secondary_reload,
5316 "Many machines have some registers that cannot be copied directly to or\n\
5317from memory or even from other types of registers. An example is the\n\
5318@samp{MQ} register, which on most machines, can only be copied to or\n\
5319from general registers, but not memory. Below, we shall be using the\n\
5320term 'intermediate register' when a move operation cannot be performed\n\
5321directly, but has to be done by copying the source into the intermediate\n\
5322register first, and then copying the intermediate register to the\n\
5323destination. An intermediate register always has the same mode as\n\
5324source and destination. Since it holds the actual value being copied,\n\
5325reload might apply optimizations to re-use an intermediate register\n\
5326and eliding the copy from the source when it can determine that the\n\
5327intermediate register still holds the required value.\n\
5328\n\
5329Another kind of secondary reload is required on some machines which\n\
5330allow copying all registers to and from memory, but require a scratch\n\
5331register for stores to some memory locations (e.g., those with symbolic\n\
5332address on the RT, and those with certain symbolic address on the SPARC\n\
5333when compiling PIC)@. Scratch registers need not have the same mode\n\
5334as the value being copied, and usually hold a different value than\n\
5335that being copied. Special patterns in the md file are needed to\n\
5336describe how the copy is performed with the help of the scratch register;\n\
5337these patterns also describe the number, register class(es) and mode(s)\n\
5338of the scratch register(s).\n\
5339\n\
5340In some cases, both an intermediate and a scratch register are required.\n\
5341\n\
5342For input reloads, this target hook is called with nonzero @var{in_p},\n\
5343and @var{x} is an rtx that needs to be copied to a register of class\n\
5344@var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
5345hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
5346needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
5347\n\
5348If copying a register of @var{reload_class} from/to @var{x} requires\n\
5349an intermediate register, the hook @code{secondary_reload} should\n\
5350return the register class required for this intermediate register.\n\
5351If no intermediate register is required, it should return NO_REGS.\n\
5352If more than one intermediate register is required, describe the one\n\
5353that is closest in the copy chain to the reload register.\n\
5354\n\
5355If scratch registers are needed, you also have to describe how to\n\
5356perform the copy from/to the reload register to/from this\n\
5357closest intermediate register. Or if no intermediate register is\n\
5358required, but still a scratch register is needed, describe the\n\
5359copy from/to the reload register to/from the reload operand @var{x}.\n\
5360\n\
5361You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
5362in the md file which performs the move. Operands 0 and 1 are the output\n\
5363and input of this copy, respectively. Operands from operand 2 onward are\n\
5364for scratch operands. These scratch operands must have a mode, and a\n\
5365single-register-class\n\
5366@c [later: or memory]\n\
5367output constraint.\n\
5368\n\
5369When an intermediate register is used, the @code{secondary_reload}\n\
5370hook will be called again to determine how to copy the intermediate\n\
5371register to/from the reload operand @var{x}, so your hook must also\n\
5372have code to handle the register class of the intermediate operand.\n\
5373\n\
5374@c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5375@c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5376@c and match the constraints of input and output to determine the required\n\
5377@c alternative. A restriction would be that constraints used to match\n\
5378@c against reloads registers would have to be written as register class\n\
5379@c constraints, or we need a new target macro / hook that tells us if an\n\
5380@c arbitrary constraint can match an unknown register of a given class.\n\
5381@c Such a macro / hook would also be useful in other places.]\n\
5382\n\
5383\n\
5384@var{x} might be a pseudo-register or a @code{subreg} of a\n\
5385pseudo-register, which could either be in a hard register or in memory.\n\
5386Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5387in memory and the hard register number if it is in a register.\n\
5388\n\
5389Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5390currently not supported. For the time being, you will have to continue\n\
5391to use @code{TARGET_SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5392\n\
5393@code{copy_cost} also uses this target hook to find out how values are\n\
5394copied. If you want it to include some extra cost for the need to allocate\n\
5395(a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5396Or if two dependent moves are supposed to have a lower cost than the sum\n\
5397of the individual moves due to expected fortuitous scheduling and/or special\n\
5398forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5399 reg_class_t,
5400 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5401 secondary_reload_info *sri),
5402 default_secondary_reload)
5403
5404DEFHOOK
5405(secondary_memory_needed,
5406 "Certain machines have the property that some registers cannot be copied\n\
5407to some other registers without using memory. Define this hook on\n\
5408those machines to return true if objects of mode @var{m} in registers\n\
5409of @var{class1} can only be copied to registers of class @var{class2} by\n\
5410 storing a register of @var{class1} into memory and loading that memory\n\
5411location into a register of @var{class2}. The default definition returns\n\
5412false for all inputs.",
5413 bool, (machine_mode mode, reg_class_t class1, reg_class_t class2),
5414 hook_bool_mode_reg_class_t_reg_class_t_false)
5415
5416DEFHOOK
5417(secondary_memory_needed_mode,
5418 "If @code{TARGET_SECONDARY_MEMORY_NEEDED} tells the compiler to use memory\n\
5419when moving between two particular registers of mode @var{mode},\n\
5420this hook specifies the mode that the memory should have.\n\
5421\n\
5422The default depends on @code{TARGET_LRA_P}. Without LRA, the default\n\
5423is to use a word-sized mode for integral modes that are smaller than a\n\
5424a word. This is right thing to do on most machines because it ensures\n\
5425that all bits of the register are copied and prevents accesses to the\n\
5426registers in a narrower mode, which some machines prohibit for\n\
5427floating-point registers.\n\
5428\n\
5429However, this default behavior is not correct on some machines, such as\n\
5430the DEC Alpha, that store short integers in floating-point registers\n\
5431differently than in integer registers. On those machines, the default\n\
5432widening will not work correctly and you must define this hook to\n\
5433suppress that widening in some cases. See the file @file{alpha.c} for\n\
5434details.\n\
5435\n\
5436With LRA, the default is to use @var{mode} unmodified.",
5437 machine_mode, (machine_mode mode),
5438 default_secondary_memory_needed_mode)
5439
5440/* Given an rtx X being reloaded into a reg required to be in class CLASS,
5441 return the class of reg to actually use. */
5442DEFHOOK
5443(preferred_reload_class,
5444 "A target hook that places additional restrictions on the register class\n\
5445to use when it is necessary to copy value @var{x} into a register in class\n\
5446@var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5447another, smaller class.\n\
5448\n\
5449The default version of this hook always returns value of @code{rclass} argument.\n\
5450\n\
5451Sometimes returning a more restrictive class makes better code. For\n\
5452example, on the 68000, when @var{x} is an integer constant that is in range\n\
5453for a @samp{moveq} instruction, the value of this macro is always\n\
5454@code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5455Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5456\n\
5457One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5458@var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5459loaded into some register class. By returning @code{NO_REGS} you can\n\
5460force @var{x} into a memory location. For example, rs6000 can load\n\
5461immediate values into general-purpose registers, but does not have an\n\
5462instruction for loading an immediate value into a floating-point\n\
5463register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5464@var{x} is a floating-point constant. If the constant can't be loaded\n\
5465into any kind of register, code generation will be better if\n\
5466@code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5467of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5468\n\
5469If an insn has pseudos in it after register allocation, reload will go\n\
5470through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5471to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5472reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5473this feature to discourage usage of 387 registers when math is done in\n\
5474the SSE registers (and vice versa).",
5475 reg_class_t,
5476 (rtx x, reg_class_t rclass),
5477 default_preferred_reload_class)
5478
5479/* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5480 input reloads. */
5481DEFHOOK
5482(preferred_output_reload_class,
5483 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5484input reloads.\n\
5485\n\
5486The default version of this hook always returns value of @code{rclass}\n\
5487argument.\n\
5488\n\
5489You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5490reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5491 reg_class_t,
5492 (rtx x, reg_class_t rclass),
5493 default_preferred_output_reload_class)
5494
5495DEFHOOK
5496(class_likely_spilled_p,
5497 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5498to registers of class @var{rclass} would likely be spilled because\n\
5499registers of @var{rclass} are needed for spill registers.\n\
5500\n\
5501The default version of this target hook returns @code{true} if @var{rclass}\n\
5502has exactly one register and @code{false} otherwise. On most machines, this\n\
5503default should be used. For generally register-starved machines, such as\n\
5504i386, or machines with right register constraints, such as SH, this hook\n\
5505can be used to avoid excessive spilling.\n\
5506\n\
5507This hook is also used by some of the global intra-procedural code\n\
5508transformations to throtle code motion, to avoid increasing register\n\
5509pressure.",
5510 bool, (reg_class_t rclass),
5511 default_class_likely_spilled_p)
5512
5513/* Return the maximum number of consecutive registers
5514 needed to represent mode MODE in a register of class RCLASS. */
5515DEFHOOK
5516(class_max_nregs,
5517 "A target hook returns the maximum number of consecutive registers\n\
5518of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5519\n\
5520This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}.\n\
5521In fact, the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5522@var{mode})} target hook should be the maximum value of\n\
5523@code{TARGET_HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5524values in the class @var{rclass}.\n\
5525\n\
5526This target hook helps control the handling of multiple-word values\n\
5527in the reload pass.\n\
5528\n\
5529The default version of this target hook returns the size of @var{mode}\n\
5530in words.",
5531 unsigned char, (reg_class_t rclass, machine_mode mode),
5532 default_class_max_nregs)
5533
5534DEFHOOK
5535(preferred_rename_class,
5536 "A target hook that places additional preference on the register\
5537 class to use when it is necessary to rename a register in class\
5538 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
5539 preferred register class is found or hook @code{preferred_rename_class}\
5540 is not implemented.\
5541 Sometimes returning a more restrictive class makes better code. For\
5542 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
5543 smaller than instructions using @code{GENERIC_REGS}. By returning\
5544 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
5545 be reduced.",
5546 reg_class_t, (reg_class_t rclass),
5547 default_preferred_rename_class)
5548
5549/* This target hook allows the backend to avoid unsafe substitution
5550 during register allocation. */
5551DEFHOOK
5552(cannot_substitute_mem_equiv_p,
5553 "A target hook which returns @code{true} if @var{subst} can't\n\
5554substitute safely pseudos with equivalent memory values during\n\
5555register allocation.\n\
5556The default version of this target hook returns @code{false}.\n\
5557On most machines, this default should be used. For generally\n\
5558machines with non orthogonal register usage for addressing, such\n\
5559as SH, this hook can be used to avoid excessive spilling.",
5560 bool, (rtx subst),
5561 hook_bool_rtx_false)
5562
5563/* This target hook allows the backend to legitimize base plus
5564 displacement addressing. */
5565DEFHOOK
5566(legitimize_address_displacement,
5567 "A target hook which returns @code{true} if *@var{disp} is\n\
5568legitimezed to valid address displacement with subtracting *@var{offset}\n\
5569at memory mode @var{mode}.\n\
5570The default version of this target hook returns @code{false}.\n\
5571This hook will benefit machines with limited base plus displacement\n\
5572addressing.",
5573 bool, (rtx *disp, rtx *offset, machine_mode mode),
5574 default_legitimize_address_displacement)
5575
5576/* This target hook allows the backend to perform additional
5577 processing while initializing for variable expansion. */
5578DEFHOOK
5579(expand_to_rtl_hook,
5580 "This hook is called just before expansion into rtl, allowing the target\n\
5581to perform additional initializations or analysis before the expansion.\n\
5582For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5583for use in copying SDmode values between memory and floating point\n\
5584registers whenever the function being expanded has any SDmode\n\
5585usage.",
5586 void, (void),
5587 hook_void_void)
5588
5589/* This target hook allows the backend to perform additional
5590 instantiations on rtx that are not actually in insns yet,
5591 but will be later. */
5592DEFHOOK
5593(instantiate_decls,
5594 "This hook allows the backend to perform additional instantiations on rtl\n\
5595that are not actually in any insns yet, but will be later.",
5596 void, (void),
5597 hook_void_void)
5598
5599DEFHOOK
5600(hard_regno_nregs,
5601 "This hook returns the number of consecutive hard registers, starting\n\
5602at register number @var{regno}, required to hold a value of mode\n\
5603@var{mode}. This hook must never return zero, even if a register\n\
5604cannot hold the requested mode - indicate that with\n\
5605@code{TARGET_HARD_REGNO_MODE_OK} and/or\n\
5606@code{TARGET_CAN_CHANGE_MODE_CLASS} instead.\n\
5607\n\
5608The default definition returns the number of words in @var{mode}.",
5609 unsigned int, (unsigned int regno, machine_mode mode),
5610 default_hard_regno_nregs)
5611
5612DEFHOOK
5613(hard_regno_mode_ok,
5614 "This hook returns true if it is permissible to store a value\n\
5615of mode @var{mode} in hard register number @var{regno} (or in several\n\
5616registers starting with that one). The default definition returns true\n\
5617unconditionally.\n\
5618\n\
5619You need not include code to check for the numbers of fixed registers,\n\
5620because the allocation mechanism considers them to be always occupied.\n\
5621\n\
5622@cindex register pairs\n\
5623On some machines, double-precision values must be kept in even/odd\n\
5624register pairs. You can implement that by defining this hook to reject\n\
5625odd register numbers for such modes.\n\
5626\n\
5627The minimum requirement for a mode to be OK in a register is that the\n\
5628@samp{mov@var{mode}} instruction pattern support moves between the\n\
5629register and other hard register in the same class and that moving a\n\
5630value into the register and back out not alter it.\n\
5631\n\
5632Since the same instruction used to move @code{word_mode} will work for\n\
5633all narrower integer modes, it is not necessary on any machine for\n\
5634this hook to distinguish between these modes, provided you define\n\
5635patterns @samp{movhi}, etc., to take advantage of this. This is\n\
5636useful because of the interaction between @code{TARGET_HARD_REGNO_MODE_OK}\n\
5637and @code{TARGET_MODES_TIEABLE_P}; it is very desirable for all integer\n\
5638modes to be tieable.\n\
5639\n\
5640Many machines have special registers for floating point arithmetic.\n\
5641Often people assume that floating point machine modes are allowed only\n\
5642in floating point registers. This is not true. Any registers that\n\
5643can hold integers can safely @emph{hold} a floating point machine\n\
5644mode, whether or not floating arithmetic can be done on it in those\n\
5645registers. Integer move instructions can be used to move the values.\n\
5646\n\
5647On some machines, though, the converse is true: fixed-point machine\n\
5648modes may not go in floating registers. This is true if the floating\n\
5649registers normalize any value stored in them, because storing a\n\
5650non-floating value there would garble it. In this case,\n\
5651@code{TARGET_HARD_REGNO_MODE_OK} should reject fixed-point machine modes in\n\
5652floating registers. But if the floating registers do not automatically\n\
5653normalize, if you can store any bit pattern in one and retrieve it\n\
5654unchanged without a trap, then any machine mode may go in a floating\n\
5655register, so you can define this hook to say so.\n\
5656\n\
5657The primary significance of special floating registers is rather that\n\
5658they are the registers acceptable in floating point arithmetic\n\
5659instructions. However, this is of no concern to\n\
5660@code{TARGET_HARD_REGNO_MODE_OK}. You handle it by writing the proper\n\
5661constraints for those instructions.\n\
5662\n\
5663On some machines, the floating registers are especially slow to access,\n\
5664so that it is better to store a value in a stack frame than in such a\n\
5665register if floating point arithmetic is not being done. As long as the\n\
5666floating registers are not in class @code{GENERAL_REGS}, they will not\n\
5667be used unless some pattern's constraint asks for one.",
5668 bool, (unsigned int regno, machine_mode mode),
5669 hook_bool_uint_mode_true)
5670
5671DEFHOOK
5672(modes_tieable_p,
5673 "This hook returns true if a value of mode @var{mode1} is accessible\n\
5674in mode @var{mode2} without copying.\n\
5675\n\
5676If @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and\n\
5677@code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always\n\
5678the same for any @var{r}, then\n\
5679@code{TARGET_MODES_TIEABLE_P (@var{mode1}, @var{mode2})}\n\
5680should be true. If they differ for any @var{r}, you should define\n\
5681this hook to return false unless some other mechanism ensures the\n\
5682accessibility of the value in a narrower mode.\n\
5683\n\
5684You should define this hook to return true in as many cases as\n\
5685possible since doing so will allow GCC to perform better register\n\
5686allocation. The default definition returns true unconditionally.",
5687 bool, (machine_mode mode1, machine_mode mode2),
5688 hook_bool_mode_mode_true)
5689
5690/* Return true if is OK to use a hard register REGNO as scratch register
5691 in peephole2. */
5692DEFHOOK
5693(hard_regno_scratch_ok,
5694 "This target hook should return @code{true} if it is OK to use a hard register\n\
5695@var{regno} as scratch reg in peephole2.\n\
5696\n\
5697One common use of this macro is to prevent using of a register that\n\
5698is not saved by a prologue in an interrupt handler.\n\
5699\n\
5700The default version of this hook always returns @code{true}.",
5701 bool, (unsigned int regno),
5702 default_hard_regno_scratch_ok)
5703
5704DEFHOOK
5705(hard_regno_call_part_clobbered,
5706 "This hook should return true if @var{regno} is partly call-saved and\n\
5707partly call-clobbered, and if a value of mode @var{mode} would be partly\n\
5708clobbered by a call. For example, if the low 32 bits of @var{regno} are\n\
5709preserved across a call but higher bits are clobbered, this hook should\n\
5710return true for a 64-bit mode but false for a 32-bit mode.\n\
5711\n\
5712The default implementation returns false, which is correct\n\
5713for targets that don't have partly call-clobbered registers.",
5714 bool, (unsigned int regno, machine_mode mode),
5715 hook_bool_uint_mode_false)
5716
5717/* Return the smallest number of different values for which it is best to
5718 use a jump-table instead of a tree of conditional branches. */
5719DEFHOOK
5720(case_values_threshold,
5721 "This function return the smallest number of different values for which it\n\
5722is best to use a jump-table instead of a tree of conditional branches.\n\
5723The default is four for machines with a @code{casesi} instruction and\n\
5724five otherwise. This is best for most machines.",
5725 unsigned int, (void),
5726 default_case_values_threshold)
5727
5728DEFHOOK
5729(starting_frame_offset,
5730 "This hook returns the offset from the frame pointer to the first local\n\
5731variable slot to be allocated. If @code{FRAME_GROWS_DOWNWARD}, it is the\n\
5732offset to @emph{end} of the first slot allocated, otherwise it is the\n\
5733offset to @emph{beginning} of the first slot allocated. The default\n\
5734implementation returns 0.",
5735 HOST_WIDE_INT, (void),
5736 hook_hwi_void_0)
5737
5738/* Optional callback to advise the target to compute the frame layout. */
5739DEFHOOK
5740(compute_frame_layout,
5741 "This target hook is called once each time the frame layout needs to be\n\
5742recalculated. The calculations can be cached by the target and can then\n\
5743be used by @code{INITIAL_ELIMINATION_OFFSET} instead of re-computing the\n\
5744layout on every invocation of that hook. This is particularly useful\n\
5745for targets that have an expensive frame layout function. Implementing\n\
5746this callback is optional.",
5747 void, (void),
5748 hook_void_void)
5749
5750/* Return true if a function must have and use a frame pointer. */
5751DEFHOOK
5752(frame_pointer_required,
5753 "This target hook should return @code{true} if a function must have and use\n\
5754a frame pointer. This target hook is called in the reload pass. If its return\n\
5755value is @code{true} the function will have a frame pointer.\n\
5756\n\
5757This target hook can in principle examine the current function and decide\n\
5758according to the facts, but on most machines the constant @code{false} or the\n\
5759constant @code{true} suffices. Use @code{false} when the machine allows code\n\
5760to be generated with no frame pointer, and doing so saves some time or space.\n\
5761Use @code{true} when there is no possible advantage to avoiding a frame\n\
5762pointer.\n\
5763\n\
5764In certain cases, the compiler does not know how to produce valid code\n\
5765without a frame pointer. The compiler recognizes those cases and\n\
5766automatically gives the function a frame pointer regardless of what\n\
5767@code{targetm.frame_pointer_required} returns. You don't need to worry about\n\
5768them.\n\
5769\n\
5770In a function that does not require a frame pointer, the frame pointer\n\
5771register can be allocated for ordinary usage, unless you mark it as a\n\
5772fixed register. See @code{FIXED_REGISTERS} for more information.\n\
5773\n\
5774Default return value is @code{false}.",
5775 bool, (void),
5776 hook_bool_void_false)
5777
5778/* Returns true if the compiler is allowed to try to replace register number
5779 from-reg with register number to-reg. */
5780DEFHOOK
5781(can_eliminate,
5782 "This target hook should return @code{true} if the compiler is allowed to\n\
5783try to replace register number @var{from_reg} with register number\n\
5784@var{to_reg}. This target hook will usually be @code{true}, since most of the\n\
5785cases preventing register elimination are things that the compiler already\n\
5786knows about.\n\
5787\n\
5788Default return value is @code{true}.",
5789 bool, (const int from_reg, const int to_reg),
5790 hook_bool_const_int_const_int_true)
5791
5792/* Modify any or all of fixed_regs, call_used_regs, global_regs,
5793 reg_names, and reg_class_contents to account of the vagaries of the
5794 target. */
5795DEFHOOK
5796(conditional_register_usage,
5797 "This hook may conditionally modify five variables\n\
5798@code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
5799@code{reg_names}, and @code{reg_class_contents}, to take into account\n\
5800any dependence of these register sets on target flags. The first three\n\
5801of these are of type @code{char []} (interpreted as boolean vectors).\n\
5802@code{global_regs} is a @code{const char *[]}, and\n\
5803@code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
5804called, @code{fixed_regs}, @code{call_used_regs},\n\
5805@code{reg_class_contents}, and @code{reg_names} have been initialized\n\
5806from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
5807@code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
5808@code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
5809@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
5810command options have been applied.\n\
5811\n\
5812@cindex disabling certain registers\n\
5813@cindex controlling register usage\n\
5814If the usage of an entire class of registers depends on the target\n\
5815flags, you may indicate this to GCC by using this macro to modify\n\
5816@code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
5817registers in the classes which should not be used by GCC@. Also make\n\
5818@code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
5819that shouldn't be used.\n\
5820\n\
5821(However, if this class is not included in @code{GENERAL_REGS} and all\n\
5822of the insn patterns whose constraints permit this class are\n\
5823controlled by target switches, then GCC will automatically avoid using\n\
5824these registers when the target switches are opposed to them.)",
5825 void, (void),
5826 hook_void_void)
5827
5828DEFHOOK
5829(stack_clash_protection_final_dynamic_probe,
5830 "Some targets make optimistic assumptions about the state of stack probing when they emit their prologues. On such targets a probe into the end of any dynamically allocated space is likely required for safety against stack clash style attacks. Define this variable to return nonzero if such a probe is required or zero otherwise. You need not define this macro if it would always have the value zero.",
5831 bool, (rtx residual),
5832 default_stack_clash_protection_final_dynamic_probe)
5833
5834
5835/* Functions specific to the C family of frontends. */
5836#undef HOOK_PREFIX
5837#define HOOK_PREFIX "TARGET_C_"
5838HOOK_VECTOR (TARGET_C, c)
5839
5840/* ??? Documenting this hook requires a GFDL license grant. */
5841DEFHOOK_UNDOC
5842(mode_for_suffix,
5843"Return machine mode for non-standard constant literal suffix @var{c},\
5844 or VOIDmode if non-standard suffixes are unsupported.",
5845 machine_mode, (char c),
5846 default_mode_for_suffix)
5847
5848DEFHOOK
5849(excess_precision,
5850 "Return a value, with the same meaning as the C99 macro\
5851 @code{FLT_EVAL_METHOD} that describes which excess precision should be\
5852 applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\
5853 @code{EXCESS_PRECISION_TYPE_FAST}, or\
5854 @code{EXCESS_PRECISION_TYPE_STANDARD}. For\
5855 @code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\
5856 precision and range operations will be implictly evaluated in regardless\
5857 of the excess precision explicitly added. For\
5858 @code{EXCESS_PRECISION_TYPE_STANDARD} and\
5859 @code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\
5860 explicit excess precision that should be added depending on the\
5861 value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{]}}.\
5862 Note that unpredictable explicit excess precision does not make sense,\
5863 so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\
5864 when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD} or\
5865 @code{EXCESS_PRECISION_TYPE_FAST}.",
5866 enum flt_eval_method, (enum excess_precision_type type),
5867 default_excess_precision)
5868
5869HOOK_VECTOR_END (c)
5870
5871/* Functions specific to the C++ frontend. */
5872#undef HOOK_PREFIX
5873#define HOOK_PREFIX "TARGET_CXX_"
5874HOOK_VECTOR (TARGET_CXX, cxx)
5875
5876/* Return the integer type used for guard variables. */
5877DEFHOOK
5878(guard_type,
5879 "Define this hook to override the integer type used for guard variables.\n\
5880These are used to implement one-time construction of static objects. The\n\
5881default is long_long_integer_type_node.",
5882 tree, (void),
5883 default_cxx_guard_type)
5884
5885/* Return true if only the low bit of the guard should be tested. */
5886DEFHOOK
5887(guard_mask_bit,
5888 "This hook determines how guard variables are used. It should return\n\
5889@code{false} (the default) if the first byte should be used. A return value of\n\
5890@code{true} indicates that only the least significant bit should be used.",
5891 bool, (void),
5892 hook_bool_void_false)
5893
5894/* Returns the size of the array cookie for an array of type. */
5895DEFHOOK
5896(get_cookie_size,
5897 "This hook returns the size of the cookie to use when allocating an array\n\
5898whose elements have the indicated @var{type}. Assumes that it is already\n\
5899known that a cookie is needed. The default is\n\
5900@code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
5901IA64/Generic C++ ABI@.",
5902 tree, (tree type),
5903 default_cxx_get_cookie_size)
5904
5905/* Returns true if the element size should be stored in the array cookie. */
5906DEFHOOK
5907(cookie_has_size,
5908 "This hook should return @code{true} if the element size should be stored in\n\
5909array cookies. The default is to return @code{false}.",
5910 bool, (void),
5911 hook_bool_void_false)
5912
5913/* Allows backends to perform additional processing when
5914 deciding if a class should be exported or imported. */
5915DEFHOOK
5916(import_export_class,
5917 "If defined by a backend this hook allows the decision made to export\n\
5918class @var{type} to be overruled. Upon entry @var{import_export}\n\
5919will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
5920to be imported and 0 otherwise. This function should return the\n\
5921modified value and perform any other actions necessary to support the\n\
5922backend's targeted operating system.",
5923 int, (tree type, int import_export), NULL)
5924
5925/* Returns true if constructors and destructors return "this". */
5926DEFHOOK
5927(cdtor_returns_this,
5928 "This hook should return @code{true} if constructors and destructors return\n\
5929the address of the object created/destroyed. The default is to return\n\
5930@code{false}.",
5931 bool, (void),
5932 hook_bool_void_false)
5933
5934/* Returns true if the key method for a class can be an inline
5935 function, so long as it is not declared inline in the class
5936 itself. Returning true is the behavior required by the Itanium C++ ABI. */
5937DEFHOOK
5938(key_method_may_be_inline,
5939 "This hook returns true if the key method for a class (i.e., the method\n\
5940which, if defined in the current translation unit, causes the virtual\n\
5941table to be emitted) may be an inline function. Under the standard\n\
5942Itanium C++ ABI the key method may be an inline function so long as\n\
5943the function is not declared inline in the class definition. Under\n\
5944some variants of the ABI, an inline function can never be the key\n\
5945method. The default is to return @code{true}.",
5946 bool, (void),
5947 hook_bool_void_true)
5948
5949DEFHOOK
5950(determine_class_data_visibility,
5951"@var{decl} is a virtual table, virtual table table, typeinfo object,\
5952 or other similar implicit class data object that will be emitted with\
5953 external linkage in this translation unit. No ELF visibility has been\
5954 explicitly specified. If the target needs to specify a visibility\
5955 other than that of the containing class, use this hook to set\
5956 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
5957 void, (tree decl),
5958 hook_void_tree)
5959
5960/* Returns true (the default) if virtual tables and other
5961 similar implicit class data objects are always COMDAT if they
5962 have external linkage. If this hook returns false, then
5963 class data for classes whose virtual table will be emitted in
5964 only one translation unit will not be COMDAT. */
5965DEFHOOK
5966(class_data_always_comdat,
5967 "This hook returns true (the default) if virtual tables and other\n\
5968similar implicit class data objects are always COMDAT if they have\n\
5969external linkage. If this hook returns false, then class data for\n\
5970classes whose virtual table will be emitted in only one translation\n\
5971unit will not be COMDAT.",
5972 bool, (void),
5973 hook_bool_void_true)
5974
5975/* Returns true (the default) if the RTTI for the basic types,
5976 which is always defined in the C++ runtime, should be COMDAT;
5977 false if it should not be COMDAT. */
5978DEFHOOK
5979(library_rtti_comdat,
5980 "This hook returns true (the default) if the RTTI information for\n\
5981the basic types which is defined in the C++ runtime should always\n\
5982be COMDAT, false if it should not be COMDAT.",
5983 bool, (void),
5984 hook_bool_void_true)
5985
5986/* Returns true if __aeabi_atexit should be used to register static
5987 destructors. */
5988DEFHOOK
5989(use_aeabi_atexit,
5990 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
5991should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
5992is in effect. The default is to return false to use @code{__cxa_atexit}.",
5993 bool, (void),
5994 hook_bool_void_false)
5995
5996/* Returns true if target may use atexit in the same manner as
5997 __cxa_atexit to register static destructors. */
5998DEFHOOK
5999(use_atexit_for_cxa_atexit,
6000 "This hook returns true if the target @code{atexit} function can be used\n\
6001in the same manner as @code{__cxa_atexit} to register C++ static\n\
6002destructors. This requires that @code{atexit}-registered functions in\n\
6003shared libraries are run in the correct order when the libraries are\n\
6004unloaded. The default is to return false.",
6005 bool, (void),
6006 hook_bool_void_false)
6007
6008DEFHOOK
6009(adjust_class_at_definition,
6010"@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
6011 been defined. Use this hook to make adjustments to the class (eg, tweak\
6012 visibility or perform any other required target modifications).",
6013 void, (tree type),
6014 hook_void_tree)
6015
6016DEFHOOK
6017(decl_mangling_context,
6018 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
6019 tree, (const_tree decl),
6020 hook_tree_const_tree_null)
6021
6022HOOK_VECTOR_END (cxx)
6023
6024/* Functions and data for emulated TLS support. */
6025#undef HOOK_PREFIX
6026#define HOOK_PREFIX "TARGET_EMUTLS_"
6027HOOK_VECTOR (TARGET_EMUTLS, emutls)
6028
6029/* Name of the address and common functions. */
6030DEFHOOKPOD
6031(get_address,
6032 "Contains the name of the helper function that uses a TLS control\n\
6033object to locate a TLS instance. The default causes libgcc's\n\
6034emulated TLS helper function to be used.",
6035 const char *, "__builtin___emutls_get_address")
6036
6037DEFHOOKPOD
6038(register_common,
6039 "Contains the name of the helper function that should be used at\n\
6040program startup to register TLS objects that are implicitly\n\
6041initialized to zero. If this is @code{NULL}, all TLS objects will\n\
6042have explicit initializers. The default causes libgcc's emulated TLS\n\
6043registration function to be used.",
6044 const char *, "__builtin___emutls_register_common")
6045
6046/* Prefixes for proxy variable and template. */
6047DEFHOOKPOD
6048(var_section,
6049 "Contains the name of the section in which TLS control variables should\n\
6050be placed. The default of @code{NULL} allows these to be placed in\n\
6051any section.",
6052 const char *, NULL)
6053
6054DEFHOOKPOD
6055(tmpl_section,
6056 "Contains the name of the section in which TLS initializers should be\n\
6057placed. The default of @code{NULL} allows these to be placed in any\n\
6058section.",
6059 const char *, NULL)
6060
6061/* Prefixes for proxy variable and template. */
6062DEFHOOKPOD
6063(var_prefix,
6064 "Contains the prefix to be prepended to TLS control variable names.\n\
6065The default of @code{NULL} uses a target-specific prefix.",
6066 const char *, NULL)
6067
6068DEFHOOKPOD
6069(tmpl_prefix,
6070 "Contains the prefix to be prepended to TLS initializer objects. The\n\
6071default of @code{NULL} uses a target-specific prefix.",
6072 const char *, NULL)
6073
6074/* Function to generate field definitions of the proxy variable. */
6075DEFHOOK
6076(var_fields,
6077 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
6078object type. @var{type} is the RECORD_TYPE the fields are for and\n\
6079@var{name} should be filled with the structure tag, if the default of\n\
6080@code{__emutls_object} is unsuitable. The default creates a type suitable\n\
6081for libgcc's emulated TLS function.",
6082 tree, (tree type, tree *name),
6083 default_emutls_var_fields)
6084
6085/* Function to initialize a proxy variable. */
6086DEFHOOK
6087(var_init,
6088 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
6089TLS control object. @var{var} is the TLS control object, @var{decl}\n\
6090is the TLS object and @var{tmpl_addr} is the address of the\n\
6091initializer. The default initializes libgcc's emulated TLS control object.",
6092 tree, (tree var, tree decl, tree tmpl_addr),
6093 default_emutls_var_init)
6094
6095/* Whether we are allowed to alter the usual alignment of the
6096 proxy variable. */
6097DEFHOOKPOD
6098(var_align_fixed,
6099 "Specifies whether the alignment of TLS control variable objects is\n\
6100fixed and should not be increased as some backends may do to optimize\n\
6101single objects. The default is false.",
6102 bool, false)
6103
6104/* Whether we can emit debug information for TLS vars. */
6105DEFHOOKPOD
6106(debug_form_tls_address,
6107 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
6108may be used to describe emulated TLS control objects.",
6109 bool, false)
6110
6111HOOK_VECTOR_END (emutls)
6112
6113#undef HOOK_PREFIX
6114#define HOOK_PREFIX "TARGET_OPTION_"
6115HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
6116
6117/* Function to validate the attribute((target(...))) strings. If
6118 the option is validated, the hook should also fill in
6119 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6120DEFHOOK
6121(valid_attribute_p,
6122 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
6123allows setting target-specific options on individual functions.\n\
6124These function-specific options may differ\n\
6125from the options specified on the command line. The hook should return\n\
6126@code{true} if the options are valid.\n\
6127\n\
6128The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6129the function declaration to hold a pointer to a target-specific\n\
6130@code{struct cl_target_option} structure.",
6131 bool, (tree fndecl, tree name, tree args, int flags),
6132 default_target_option_valid_attribute_p)
6133
6134/* Function to save any extra target state in the target options structure. */
6135DEFHOOK
6136(save,
6137 "This hook is called to save any additional target-specific information\n\
6138in the @code{struct cl_target_option} structure for function-specific\n\
6139options from the @code{struct gcc_options} structure.\n\
6140@xref{Option file format}.",
6141 void, (struct cl_target_option *ptr, struct gcc_options *opts), NULL)
6142
6143/* Function to restore any extra target state from the target options
6144 structure. */
6145DEFHOOK
6146(restore,
6147 "This hook is called to restore any additional target-specific\n\
6148information in the @code{struct cl_target_option} structure for\n\
6149function-specific options to the @code{struct gcc_options} structure.",
6150 void, (struct gcc_options *opts, struct cl_target_option *ptr), NULL)
6151
6152/* Function to update target-specific option information after being
6153 streamed in. */
6154DEFHOOK
6155(post_stream_in,
6156 "This hook is called to update target-specific information in the\n\
6157@code{struct cl_target_option} structure after it is streamed in from\n\
6158LTO bytecode.",
6159 void, (struct cl_target_option *ptr), NULL)
6160
6161/* Function to print any extra target state from the target options
6162 structure. */
6163DEFHOOK
6164(print,
6165 "This hook is called to print any additional target-specific\n\
6166information in the @code{struct cl_target_option} structure for\n\
6167function-specific options.",
6168 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
6169
6170/* Function to parse arguments to be validated for #pragma target, and to
6171 change the state if the options are valid. If the first argument is
6172 NULL, the second argument specifies the default options to use. Return
6173 true if the options are valid, and set the current state. */
6174DEFHOOK
6175(pragma_parse,
6176 "This target hook parses the options for @code{#pragma GCC target}, which\n\
6177sets the target-specific options for functions that occur later in the\n\
6178input stream. The options accepted should be the same as those handled by the\n\
6179@code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
6180 bool, (tree args, tree pop_target),
6181 default_target_option_pragma_parse)
6182
6183/* Do option overrides for the target. */
6184DEFHOOK
6185(override,
6186 "Sometimes certain combinations of command options do not make sense on\n\
6187a particular target machine. You can override the hook\n\
6188@code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
6189once just after all the command options have been parsed.\n\
6190\n\
6191Don't use this hook to turn on various extra optimizations for\n\
6192@option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
6193\n\
6194If you need to do something whenever the optimization level is\n\
6195changed via the optimize attribute or pragma, see\n\
6196@code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
6197 void, (void),
6198 hook_void_void)
6199
6200/* This function returns true if DECL1 and DECL2 are versions of the same
6201 function. DECL1 and DECL2 are function versions if and only if they
6202 have the same function signature and different target specific attributes,
6203 that is, they are compiled for different target machines. */
6204DEFHOOK
6205(function_versions,
6206 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
6207versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
6208versions if and only if they have the same function signature and\n\
6209different target specific attributes, that is, they are compiled for\n\
6210different target machines.",
6211 bool, (tree decl1, tree decl2),
6212 hook_bool_tree_tree_false)
6213
6214/* Function to determine if one function can inline another function. */
6215#undef HOOK_PREFIX
6216#define HOOK_PREFIX "TARGET_"
6217DEFHOOK
6218(can_inline_p,
6219 "This target hook returns @code{false} if the @var{caller} function\n\
6220cannot inline @var{callee}, based on target specific information. By\n\
6221default, inlining is not allowed if the callee function has function\n\
6222specific target options and the caller does not use the same options.",
6223 bool, (tree caller, tree callee),
6224 default_target_can_inline_p)
6225
6226DEFHOOK
6227(relayout_function,
6228"This target hook fixes function @var{fndecl} after attributes are processed. Default does nothing. On ARM, the default function's alignment is updated with the attribute target.",
6229 void, (tree fndecl),
6230 hook_void_tree)
6231
6232HOOK_VECTOR_END (target_option)
6233
6234/* For targets that need to mark extra registers as live on entry to
6235 the function, they should define this target hook and set their
6236 bits in the bitmap passed in. */
6237DEFHOOK
6238(extra_live_on_entry,
6239 "Add any hard registers to @var{regs} that are live on entry to the\n\
6240function. This hook only needs to be defined to provide registers that\n\
6241cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
6242registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
6243TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
6244FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
6245 void, (bitmap regs),
6246 hook_void_bitmap)
6247
6248/* Targets should define this target hook to mark that non-callee clobbers are
6249 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
6250 definition. */
6251DEFHOOKPOD
6252(call_fusage_contains_non_callee_clobbers,
6253 "Set to true if each call that binds to a local definition explicitly\n\
6254clobbers or sets all non-fixed registers modified by performing the call.\n\
6255That is, by the call pattern itself, or by code that might be inserted by the\n\
6256linker (e.g. stubs, veneers, branch islands), but not including those\n\
6257modifiable by the callee. The affected registers may be mentioned explicitly\n\
6258in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
6259The default version of this hook is set to false. The purpose of this hook\n\
6260is to enable the fipa-ra optimization.",
6261 bool,
6262 false)
6263
6264/* Fill in additional registers set up by prologue into a regset. */
6265DEFHOOK
6266(set_up_by_prologue,
6267 "This hook should add additional registers that are computed by the prologue\
6268 to the hard regset for shrink-wrapping optimization purposes.",
6269 void, (struct hard_reg_set_container *),
6270 NULL)
6271
6272/* For targets that have attributes that can affect whether a
6273 function's return statements need checking. For instance a 'naked'
6274 function attribute. */
6275DEFHOOK
6276(warn_func_return,
6277 "True if a function's return statements should be checked for matching the function's return type. This includes checking for falling off the end of a non-void function. Return false if no such check should be made.",
6278 bool, (tree),
6279 hook_bool_tree_true)
6280
6281#undef HOOK_PREFIX
6282#define HOOK_PREFIX "TARGET_SHRINK_WRAP_"
6283HOOK_VECTOR (TARGET_SHRINK_WRAP_HOOKS, shrink_wrap)
6284
6285DEFHOOK
6286(get_separate_components,
6287 "This hook should return an @code{sbitmap} with the bits set for those\n\
6288components that can be separately shrink-wrapped in the current function.\n\
6289Return @code{NULL} if the current function should not get any separate\n\
6290shrink-wrapping.\n\
6291Don't define this hook if it would always return @code{NULL}.\n\
6292If it is defined, the other hooks in this group have to be defined as well.",
6293 sbitmap, (void),
6294 NULL)
6295
6296DEFHOOK
6297(components_for_bb,
6298 "This hook should return an @code{sbitmap} with the bits set for those\n\
6299components where either the prologue component has to be executed before\n\
6300the @code{basic_block}, or the epilogue component after it, or both.",
6301 sbitmap, (basic_block),
6302 NULL)
6303
6304DEFHOOK
6305(disqualify_components,
6306 "This hook should clear the bits in the @var{components} bitmap for those\n\
6307components in @var{edge_components} that the target cannot handle on edge\n\
6308@var{e}, where @var{is_prologue} says if this is for a prologue or an\n\
6309epilogue instead.",
6310 void, (sbitmap components, edge e, sbitmap edge_components, bool is_prologue),
6311 NULL)
6312
6313DEFHOOK
6314(emit_prologue_components,
6315 "Emit prologue insns for the components indicated by the parameter.",
6316 void, (sbitmap),
6317 NULL)
6318
6319DEFHOOK
6320(emit_epilogue_components,
6321 "Emit epilogue insns for the components indicated by the parameter.",
6322 void, (sbitmap),
6323 NULL)
6324
6325DEFHOOK
6326(set_handled_components,
6327 "Mark the components in the parameter as handled, so that the\n\
6328@code{prologue} and @code{epilogue} named patterns know to ignore those\n\
6329components. The target code should not hang on to the @code{sbitmap}, it\n\
6330will be deleted after this call.",
6331 void, (sbitmap),
6332 NULL)
6333
6334HOOK_VECTOR_END (shrink_wrap)
6335#undef HOOK_PREFIX
6336#define HOOK_PREFIX "TARGET_"
6337
6338/* Determine the type of unwind info to emit for debugging. */
6339DEFHOOK
6340(debug_unwind_info,
6341 "This hook defines the mechanism that will be used for describing frame\n\
6342unwind information to the debugger. Normally the hook will return\n\
6343@code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
6344return @code{UI_NONE} otherwise.\n\
6345\n\
6346A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
6347is disabled in order to always output DWARF 2 frame information.\n\
6348\n\
6349A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
6350This will suppress generation of the normal debug frame unwind information.",
6351 enum unwind_info_type, (void),
6352 default_debug_unwind_info)
6353
6354/* The code parameter should be of type enum rtx_code but this is not
6355 defined at this time. */
6356DEFHOOK
6357(canonicalize_comparison,
6358 "On some machines not all possible comparisons are defined, but you can\n\
6359convert an invalid comparison into a valid one. For example, the Alpha\n\
6360does not have a @code{GT} comparison, but you can use an @code{LT}\n\
6361comparison instead and swap the order of the operands.\n\
6362\n\
6363On such machines, implement this hook to do any required conversions.\n\
6364@var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
6365are the left and right operands of the comparison, respectively. If\n\
6366@var{op0_preserve_value} is @code{true} the implementation is not\n\
6367allowed to change the value of @var{op0} since the value might be used\n\
6368in RTXs which aren't comparisons. E.g. the implementation is not\n\
6369allowed to swap operands in that case.\n\
6370\n\
6371GCC will not assume that the comparison resulting from this macro is\n\
6372valid but will see if the resulting insn matches a pattern in the\n\
6373@file{md} file.\n\
6374\n\
6375You need not to implement this hook if it would never change the\n\
6376comparison code or operands.",
6377 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
6378 default_canonicalize_comparison)
6379
6380DEFHOOK
6381(min_arithmetic_precision,
6382 "On some RISC architectures with 64-bit registers, the processor also\n\
6383maintains 32-bit condition codes that make it possible to do real 32-bit\n\
6384arithmetic, although the operations are performed on the full registers.\n\
6385\n\
6386On such architectures, defining this hook to 32 tells the compiler to try\n\
6387using 32-bit arithmetical operations setting the condition codes instead\n\
6388of doing full 64-bit arithmetic.\n\
6389\n\
6390More generally, define this hook on RISC architectures if you want the\n\
6391compiler to try using arithmetical operations setting the condition codes\n\
6392with a precision lower than the word precision.\n\
6393\n\
6394You need not define this hook if @code{WORD_REGISTER_OPERATIONS} is not\n\
6395defined to 1.",
6396 unsigned int, (void), default_min_arithmetic_precision)
6397
6398DEFHOOKPOD
6399(atomic_test_and_set_trueval,
6400 "This value should be set if the result written by\
6401 @code{atomic_test_and_set} is not exactly 1, i.e. the\
6402 @code{bool} @code{true}.",
6403 unsigned char, 1)
6404
6405/* Return an unsigned int representing the alignment (in bits) of the atomic
6406 type which maps to machine MODE. This allows alignment to be overridden
6407 as needed. */
6408DEFHOOK
6409(atomic_align_for_mode,
6410"If defined, this function returns an appropriate alignment in bits for an\
6411 atomic object of machine_mode @var{mode}. If 0 is returned then the\
6412 default alignment for the specified mode is used. ",
6413 unsigned int, (machine_mode mode),
6414 hook_uint_mode_0)
6415
6416DEFHOOK
6417(atomic_assign_expand_fenv,
6418"ISO C11 requires atomic compound assignments that may raise floating-point\
6419 exceptions to raise exceptions corresponding to the arithmetic operation\
6420 whose result was successfully stored in a compare-and-exchange sequence. \
6421 This requires code equivalent to calls to @code{feholdexcept},\
6422 @code{feclearexcept} and @code{feupdateenv} to be generated at\
6423 appropriate points in the compare-and-exchange sequence. This hook should\
6424 set @code{*@var{hold}} to an expression equivalent to the call to\
6425 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
6426 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
6427 equivalent to the call to @code{feupdateenv}. The three expressions are\
6428 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
6429 if no code is required in a particular place. The default implementation\
6430 leaves all three expressions as @code{NULL_TREE}. The\
6431 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
6432 as part of the code generated in @code{*@var{update}}.",
6433 void, (tree *hold, tree *clear, tree *update),
6434 default_atomic_assign_expand_fenv)
6435
6436/* Leave the boolean fields at the end. */
6437
6438/* True if we can create zeroed data by switching to a BSS section
6439 and then using ASM_OUTPUT_SKIP to allocate the space. */
6440DEFHOOKPOD
6441(have_switchable_bss_sections,
6442 "This flag is true if we can create zeroed data by switching to a BSS\n\
6443section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
6444This is true on most ELF targets.",
6445 bool, false)
6446
6447/* True if "native" constructors and destructors are supported,
6448 false if we're using collect2 for the job. */
6449DEFHOOKPOD
6450(have_ctors_dtors,
6451 "This value is true if the target supports some ``native'' method of\n\
6452collecting constructors and destructors to be run at startup and exit.\n\
6453It is false if we must use @command{collect2}.",
6454 bool, false)
6455
6456/* True if thread-local storage is supported. */
6457DEFHOOKPOD
6458(have_tls,
6459 "Contains the value true if the target supports thread-local storage.\n\
6460The default value is false.",
6461 bool, false)
6462
6463/* True if a small readonly data section is supported. */
6464DEFHOOKPOD
6465(have_srodata_section,
6466 "Contains the value true if the target places read-only\n\
6467``small data'' into a separate section. The default value is false.",
6468 bool, false)
6469
6470/* True if EH frame info sections should be zero-terminated. */
6471DEFHOOKPOD
6472(terminate_dw2_eh_frame_info,
6473 "Contains the value true if the target should add a zero word onto the\n\
6474end of a Dwarf-2 frame info section when used for exception handling.\n\
6475Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
6476true otherwise.",
6477 bool, true)
6478
6479/* True if #NO_APP should be emitted at the beginning of assembly output. */
6480DEFHOOKPOD
6481(asm_file_start_app_off,
6482 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
6483printed as the very first line in the assembly file, unless\n\
6484@option{-fverbose-asm} is in effect. (If that macro has been defined\n\
6485to the empty string, this variable has no effect.) With the normal\n\
6486definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
6487assembler that it need not bother stripping comments or extra\n\
6488whitespace from its input. This allows it to work a bit faster.\n\
6489\n\
6490The default is false. You should not set it to true unless you have\n\
6491verified that your port does not generate any extra whitespace or\n\
6492comments that will cause GAS to issue errors in NO_APP mode.",
6493 bool, false)
6494
6495/* True if output_file_directive should be called for main_input_filename
6496 at the beginning of assembly output. */
6497DEFHOOKPOD
6498(asm_file_start_file_directive,
6499 "If this flag is true, @code{output_file_directive} will be called\n\
6500for the primary source file, immediately after printing\n\
6501@code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
6502this to be done. The default is false.",
6503 bool, false)
6504
6505/* Returns true if we should generate exception tables for use with the
6506 ARM EABI. The effects the encoding of function exception specifications. */
6507DEFHOOKPOD
6508(arm_eabi_unwinder,
6509 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
6510based unwinding library, and @code{false} on other targets. This effects\n\
6511the format of unwinding tables, and how the unwinder in entered after\n\
6512running a cleanup. The default is @code{false}.",
6513 bool, false)
6514
6515DEFHOOKPOD
6516(want_debug_pub_sections,
6517 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
6518 should be emitted. These sections are not used on most platforms, and\
6519 in particular GDB does not use them.",
6520 bool, false)
6521
6522DEFHOOKPOD
6523(delay_sched2, "True if sched2 is not to be run at its normal place.\n\
6524This usually means it will be run as part of machine-specific reorg.",
6525bool, false)
6526
6527DEFHOOKPOD
6528(delay_vartrack, "True if vartrack is not to be run at its normal place.\n\
6529This usually means it will be run as part of machine-specific reorg.",
6530bool, false)
6531
6532DEFHOOKPOD
6533(no_register_allocation, "True if register allocation and the passes\n\
6534following it should not be run. Usually true only for virtual assembler\n\
6535targets.",
6536bool, false)
6537
6538/* Leave the boolean fields at the end. */
6539
6540/* Functions related to mode switching. */
6541#undef HOOK_PREFIX
6542#define HOOK_PREFIX "TARGET_MODE_"
6543HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
6544
6545DEFHOOK
6546(emit,
6547 "Generate one or more insns to set @var{entity} to @var{mode}. @var{hard_reg_live} is the set of hard registers live at the point where the insn(s) are to be inserted. @var{prev_moxde} indicates the mode to switch from. Sets of a lower numbered entity will be emitted before sets of a higher numbered entity to a mode of the same or lower priority.",
6548 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
6549
6550DEFHOOK
6551(needed,
6552 "@var{entity} is an integer specifying a mode-switched entity. If @code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to return an integer value not larger than the corresponding element in @code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must be switched into prior to the execution of @var{insn}.",
6553 int, (int entity, rtx_insn *insn), NULL)
6554
6555DEFHOOK
6556(after,
6557 "@var{entity} is an integer specifying a mode-switched entity. If this macro is defined, it is evaluated for every @var{insn} during mode switching. It determines the mode that an insn results in (if different from the incoming mode).",
6558 int, (int entity, int mode, rtx_insn *insn), NULL)
6559
6560DEFHOOK
6561(entry,
6562 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function entry. If @code{TARGET_MODE_ENTRY} is defined then @code{TARGET_MODE_EXIT} must be defined.",
6563 int, (int entity), NULL)
6564
6565DEFHOOK
6566(exit,
6567 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function exit. If @code{TARGET_MODE_EXIT} is defined then @code{TARGET_MODE_ENTRY} must be defined.",
6568 int, (int entity), NULL)
6569
6570DEFHOOK
6571(priority,
6572 "This macro specifies the order in which modes for @var{entity} are processed. 0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the lowest. The value of the macro should be an integer designating a mode for @var{entity}. For any fixed @var{entity}, @code{mode_priority} (@var{entity}, @var{n}) shall be a bijection in 0 @dots{} @code{num_modes_for_mode_switching[@var{entity}] - 1}.",
6573 int, (int entity, int n), NULL)
6574
6575HOOK_VECTOR_END (mode_switching)
6576
6577#undef HOOK_PREFIX
6578#define HOOK_PREFIX "TARGET_"
6579
6580#define DEF_TARGET_INSN(NAME, PROTO) \
6581 DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
6582#include "target-insns.def"
6583#undef DEF_TARGET_INSN
6584
6585#define DEF_TARGET_INSN(NAME, PROTO) \
6586 DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
6587#include "target-insns.def"
6588#undef DEF_TARGET_INSN
6589
6590#define DEF_TARGET_INSN(NAME, PROTO) \
6591 DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
6592#include "target-insns.def"
6593#undef DEF_TARGET_INSN
6594
6595DEFHOOK
6596(run_target_selftests,
6597 "If selftests are enabled, run any selftests for this target.",
6598 void, (void),
6599 NULL)
6600
6601/* Close the 'struct gcc_target' definition. */
6602HOOK_VECTOR_END (C90_EMPTY_HACK)
6603
6604