1/* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20
21#include "config.h"
22#include "system.h"
23#include "coretypes.h"
24#include "target.h"
25#include "function.h"
26#include "rtl.h"
27#include "tree.h"
28#include "memmodel.h"
29#include "tm_p.h"
30#include "expmed.h"
31#include "profile-count.h"
32#include "optabs.h"
33#include "emit-rtl.h"
34#include "recog.h"
35#include "diagnostic-core.h"
36#include "stor-layout.h"
37#include "except.h"
38#include "dojump.h"
39#include "explow.h"
40#include "expr.h"
41#include "common/common-target.h"
42#include "output.h"
43#include "params.h"
44
45static rtx break_out_memory_refs (rtx);
46static void anti_adjust_stack_and_probe_stack_clash (rtx);
47
48
49/* Truncate and perhaps sign-extend C as appropriate for MODE. */
50
51HOST_WIDE_INT
52trunc_int_for_mode (HOST_WIDE_INT c, machine_mode mode)
53{
54 /* Not scalar_int_mode because we also allow pointer bound modes. */
55 scalar_mode smode = as_a <scalar_mode> (mode);
56 int width = GET_MODE_PRECISION (smode);
57
58 /* You want to truncate to a _what_? */
59 gcc_assert (SCALAR_INT_MODE_P (mode)
60 || POINTER_BOUNDS_MODE_P (mode));
61
62 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
63 if (smode == BImode)
64 return c & 1 ? STORE_FLAG_VALUE : 0;
65
66 /* Sign-extend for the requested mode. */
67
68 if (width < HOST_BITS_PER_WIDE_INT)
69 {
70 HOST_WIDE_INT sign = 1;
71 sign <<= width - 1;
72 c &= (sign << 1) - 1;
73 c ^= sign;
74 c -= sign;
75 }
76
77 return c;
78}
79
80/* Return an rtx for the sum of X and the integer C, given that X has
81 mode MODE. INPLACE is true if X can be modified inplace or false
82 if it must be treated as immutable. */
83
84rtx
85plus_constant (machine_mode mode, rtx x, HOST_WIDE_INT c,
86 bool inplace)
87{
88 RTX_CODE code;
89 rtx y;
90 rtx tem;
91 int all_constant = 0;
92
93 gcc_assert (GET_MODE (x) == VOIDmode || GET_MODE (x) == mode);
94
95 if (c == 0)
96 return x;
97
98 restart:
99
100 code = GET_CODE (x);
101 y = x;
102
103 switch (code)
104 {
105 CASE_CONST_SCALAR_INT:
106 return immed_wide_int_const (wi::add (rtx_mode_t (x, mode), c), mode);
107 case MEM:
108 /* If this is a reference to the constant pool, try replacing it with
109 a reference to a new constant. If the resulting address isn't
110 valid, don't return it because we have no way to validize it. */
111 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
112 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
113 {
114 rtx cst = get_pool_constant (XEXP (x, 0));
115
116 if (GET_CODE (cst) == CONST_VECTOR
117 && GET_MODE_INNER (GET_MODE (cst)) == mode)
118 {
119 cst = gen_lowpart (mode, cst);
120 gcc_assert (cst);
121 }
122 if (GET_MODE (cst) == VOIDmode || GET_MODE (cst) == mode)
123 {
124 tem = plus_constant (mode, cst, c);
125 tem = force_const_mem (GET_MODE (x), tem);
126 /* Targets may disallow some constants in the constant pool, thus
127 force_const_mem may return NULL_RTX. */
128 if (tem && memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
129 return tem;
130 }
131 }
132 break;
133
134 case CONST:
135 /* If adding to something entirely constant, set a flag
136 so that we can add a CONST around the result. */
137 if (inplace && shared_const_p (x))
138 inplace = false;
139 x = XEXP (x, 0);
140 all_constant = 1;
141 goto restart;
142
143 case SYMBOL_REF:
144 case LABEL_REF:
145 all_constant = 1;
146 break;
147
148 case PLUS:
149 /* The interesting case is adding the integer to a sum. Look
150 for constant term in the sum and combine with C. For an
151 integer constant term or a constant term that is not an
152 explicit integer, we combine or group them together anyway.
153
154 We may not immediately return from the recursive call here, lest
155 all_constant gets lost. */
156
157 if (CONSTANT_P (XEXP (x, 1)))
158 {
159 rtx term = plus_constant (mode, XEXP (x, 1), c, inplace);
160 if (term == const0_rtx)
161 x = XEXP (x, 0);
162 else if (inplace)
163 XEXP (x, 1) = term;
164 else
165 x = gen_rtx_PLUS (mode, XEXP (x, 0), term);
166 c = 0;
167 }
168 else if (rtx *const_loc = find_constant_term_loc (&y))
169 {
170 if (!inplace)
171 {
172 /* We need to be careful since X may be shared and we can't
173 modify it in place. */
174 x = copy_rtx (x);
175 const_loc = find_constant_term_loc (&x);
176 }
177 *const_loc = plus_constant (mode, *const_loc, c, true);
178 c = 0;
179 }
180 break;
181
182 default:
183 break;
184 }
185
186 if (c != 0)
187 x = gen_rtx_PLUS (mode, x, gen_int_mode (c, mode));
188
189 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
190 return x;
191 else if (all_constant)
192 return gen_rtx_CONST (mode, x);
193 else
194 return x;
195}
196
197/* If X is a sum, return a new sum like X but lacking any constant terms.
198 Add all the removed constant terms into *CONSTPTR.
199 X itself is not altered. The result != X if and only if
200 it is not isomorphic to X. */
201
202rtx
203eliminate_constant_term (rtx x, rtx *constptr)
204{
205 rtx x0, x1;
206 rtx tem;
207
208 if (GET_CODE (x) != PLUS)
209 return x;
210
211 /* First handle constants appearing at this level explicitly. */
212 if (CONST_INT_P (XEXP (x, 1))
213 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
214 XEXP (x, 1)))
215 && CONST_INT_P (tem))
216 {
217 *constptr = tem;
218 return eliminate_constant_term (XEXP (x, 0), constptr);
219 }
220
221 tem = const0_rtx;
222 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
223 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
224 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
225 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
226 *constptr, tem))
227 && CONST_INT_P (tem))
228 {
229 *constptr = tem;
230 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
231 }
232
233 return x;
234}
235
236
237/* Return a copy of X in which all memory references
238 and all constants that involve symbol refs
239 have been replaced with new temporary registers.
240 Also emit code to load the memory locations and constants
241 into those registers.
242
243 If X contains no such constants or memory references,
244 X itself (not a copy) is returned.
245
246 If a constant is found in the address that is not a legitimate constant
247 in an insn, it is left alone in the hope that it might be valid in the
248 address.
249
250 X may contain no arithmetic except addition, subtraction and multiplication.
251 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
252
253static rtx
254break_out_memory_refs (rtx x)
255{
256 if (MEM_P (x)
257 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
258 && GET_MODE (x) != VOIDmode))
259 x = force_reg (GET_MODE (x), x);
260 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
261 || GET_CODE (x) == MULT)
262 {
263 rtx op0 = break_out_memory_refs (XEXP (x, 0));
264 rtx op1 = break_out_memory_refs (XEXP (x, 1));
265
266 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
267 x = simplify_gen_binary (GET_CODE (x), GET_MODE (x), op0, op1);
268 }
269
270 return x;
271}
272
273/* Given X, a memory address in address space AS' pointer mode, convert it to
274 an address in the address space's address mode, or vice versa (TO_MODE says
275 which way). We take advantage of the fact that pointers are not allowed to
276 overflow by commuting arithmetic operations over conversions so that address
277 arithmetic insns can be used. IN_CONST is true if this conversion is inside
278 a CONST. NO_EMIT is true if no insns should be emitted, and instead
279 it should return NULL if it can't be simplified without emitting insns. */
280
281rtx
282convert_memory_address_addr_space_1 (scalar_int_mode to_mode ATTRIBUTE_UNUSED,
283 rtx x, addr_space_t as ATTRIBUTE_UNUSED,
284 bool in_const ATTRIBUTE_UNUSED,
285 bool no_emit ATTRIBUTE_UNUSED)
286{
287#ifndef POINTERS_EXTEND_UNSIGNED
288 gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode);
289 return x;
290#else /* defined(POINTERS_EXTEND_UNSIGNED) */
291 scalar_int_mode pointer_mode, address_mode, from_mode;
292 rtx temp;
293 enum rtx_code code;
294
295 /* If X already has the right mode, just return it. */
296 if (GET_MODE (x) == to_mode)
297 return x;
298
299 pointer_mode = targetm.addr_space.pointer_mode (as);
300 address_mode = targetm.addr_space.address_mode (as);
301 from_mode = to_mode == pointer_mode ? address_mode : pointer_mode;
302
303 /* Here we handle some special cases. If none of them apply, fall through
304 to the default case. */
305 switch (GET_CODE (x))
306 {
307 CASE_CONST_SCALAR_INT:
308 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
309 code = TRUNCATE;
310 else if (POINTERS_EXTEND_UNSIGNED < 0)
311 break;
312 else if (POINTERS_EXTEND_UNSIGNED > 0)
313 code = ZERO_EXTEND;
314 else
315 code = SIGN_EXTEND;
316 temp = simplify_unary_operation (code, to_mode, x, from_mode);
317 if (temp)
318 return temp;
319 break;
320
321 case SUBREG:
322 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
323 && GET_MODE (SUBREG_REG (x)) == to_mode)
324 return SUBREG_REG (x);
325 break;
326
327 case LABEL_REF:
328 temp = gen_rtx_LABEL_REF (to_mode, label_ref_label (x));
329 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
330 return temp;
331
332 case SYMBOL_REF:
333 temp = shallow_copy_rtx (x);
334 PUT_MODE (temp, to_mode);
335 return temp;
336
337 case CONST:
338 temp = convert_memory_address_addr_space_1 (to_mode, XEXP (x, 0), as,
339 true, no_emit);
340 return temp ? gen_rtx_CONST (to_mode, temp) : temp;
341
342 case PLUS:
343 case MULT:
344 /* For addition we can safely permute the conversion and addition
345 operation if one operand is a constant and converting the constant
346 does not change it or if one operand is a constant and we are
347 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
348 We can always safely permute them if we are making the address
349 narrower. Inside a CONST RTL, this is safe for both pointers
350 zero or sign extended as pointers cannot wrap. */
351 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
352 || (GET_CODE (x) == PLUS
353 && CONST_INT_P (XEXP (x, 1))
354 && ((in_const && POINTERS_EXTEND_UNSIGNED != 0)
355 || XEXP (x, 1) == convert_memory_address_addr_space_1
356 (to_mode, XEXP (x, 1), as, in_const,
357 no_emit)
358 || POINTERS_EXTEND_UNSIGNED < 0)))
359 {
360 temp = convert_memory_address_addr_space_1 (to_mode, XEXP (x, 0),
361 as, in_const, no_emit);
362 return (temp ? gen_rtx_fmt_ee (GET_CODE (x), to_mode,
363 temp, XEXP (x, 1))
364 : temp);
365 }
366 break;
367
368 default:
369 break;
370 }
371
372 if (no_emit)
373 return NULL_RTX;
374
375 return convert_modes (to_mode, from_mode,
376 x, POINTERS_EXTEND_UNSIGNED);
377#endif /* defined(POINTERS_EXTEND_UNSIGNED) */
378}
379
380/* Given X, a memory address in address space AS' pointer mode, convert it to
381 an address in the address space's address mode, or vice versa (TO_MODE says
382 which way). We take advantage of the fact that pointers are not allowed to
383 overflow by commuting arithmetic operations over conversions so that address
384 arithmetic insns can be used. */
385
386rtx
387convert_memory_address_addr_space (scalar_int_mode to_mode, rtx x,
388 addr_space_t as)
389{
390 return convert_memory_address_addr_space_1 (to_mode, x, as, false, false);
391}
392
393
394/* Return something equivalent to X but valid as a memory address for something
395 of mode MODE in the named address space AS. When X is not itself valid,
396 this works by copying X or subexpressions of it into registers. */
397
398rtx
399memory_address_addr_space (machine_mode mode, rtx x, addr_space_t as)
400{
401 rtx oldx = x;
402 scalar_int_mode address_mode = targetm.addr_space.address_mode (as);
403
404 x = convert_memory_address_addr_space (address_mode, x, as);
405
406 /* By passing constant addresses through registers
407 we get a chance to cse them. */
408 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
409 x = force_reg (address_mode, x);
410
411 /* We get better cse by rejecting indirect addressing at this stage.
412 Let the combiner create indirect addresses where appropriate.
413 For now, generate the code so that the subexpressions useful to share
414 are visible. But not if cse won't be done! */
415 else
416 {
417 if (! cse_not_expected && !REG_P (x))
418 x = break_out_memory_refs (x);
419
420 /* At this point, any valid address is accepted. */
421 if (memory_address_addr_space_p (mode, x, as))
422 goto done;
423
424 /* If it was valid before but breaking out memory refs invalidated it,
425 use it the old way. */
426 if (memory_address_addr_space_p (mode, oldx, as))
427 {
428 x = oldx;
429 goto done;
430 }
431
432 /* Perform machine-dependent transformations on X
433 in certain cases. This is not necessary since the code
434 below can handle all possible cases, but machine-dependent
435 transformations can make better code. */
436 {
437 rtx orig_x = x;
438 x = targetm.addr_space.legitimize_address (x, oldx, mode, as);
439 if (orig_x != x && memory_address_addr_space_p (mode, x, as))
440 goto done;
441 }
442
443 /* PLUS and MULT can appear in special ways
444 as the result of attempts to make an address usable for indexing.
445 Usually they are dealt with by calling force_operand, below.
446 But a sum containing constant terms is special
447 if removing them makes the sum a valid address:
448 then we generate that address in a register
449 and index off of it. We do this because it often makes
450 shorter code, and because the addresses thus generated
451 in registers often become common subexpressions. */
452 if (GET_CODE (x) == PLUS)
453 {
454 rtx constant_term = const0_rtx;
455 rtx y = eliminate_constant_term (x, &constant_term);
456 if (constant_term == const0_rtx
457 || ! memory_address_addr_space_p (mode, y, as))
458 x = force_operand (x, NULL_RTX);
459 else
460 {
461 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
462 if (! memory_address_addr_space_p (mode, y, as))
463 x = force_operand (x, NULL_RTX);
464 else
465 x = y;
466 }
467 }
468
469 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
470 x = force_operand (x, NULL_RTX);
471
472 /* If we have a register that's an invalid address,
473 it must be a hard reg of the wrong class. Copy it to a pseudo. */
474 else if (REG_P (x))
475 x = copy_to_reg (x);
476
477 /* Last resort: copy the value to a register, since
478 the register is a valid address. */
479 else
480 x = force_reg (address_mode, x);
481 }
482
483 done:
484
485 gcc_assert (memory_address_addr_space_p (mode, x, as));
486 /* If we didn't change the address, we are done. Otherwise, mark
487 a reg as a pointer if we have REG or REG + CONST_INT. */
488 if (oldx == x)
489 return x;
490 else if (REG_P (x))
491 mark_reg_pointer (x, BITS_PER_UNIT);
492 else if (GET_CODE (x) == PLUS
493 && REG_P (XEXP (x, 0))
494 && CONST_INT_P (XEXP (x, 1)))
495 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
496
497 /* OLDX may have been the address on a temporary. Update the address
498 to indicate that X is now used. */
499 update_temp_slot_address (oldx, x);
500
501 return x;
502}
503
504/* Convert a mem ref into one with a valid memory address.
505 Pass through anything else unchanged. */
506
507rtx
508validize_mem (rtx ref)
509{
510 if (!MEM_P (ref))
511 return ref;
512 ref = use_anchored_address (ref);
513 if (memory_address_addr_space_p (GET_MODE (ref), XEXP (ref, 0),
514 MEM_ADDR_SPACE (ref)))
515 return ref;
516
517 /* Don't alter REF itself, since that is probably a stack slot. */
518 return replace_equiv_address (ref, XEXP (ref, 0));
519}
520
521/* If X is a memory reference to a member of an object block, try rewriting
522 it to use an anchor instead. Return the new memory reference on success
523 and the old one on failure. */
524
525rtx
526use_anchored_address (rtx x)
527{
528 rtx base;
529 HOST_WIDE_INT offset;
530 machine_mode mode;
531
532 if (!flag_section_anchors)
533 return x;
534
535 if (!MEM_P (x))
536 return x;
537
538 /* Split the address into a base and offset. */
539 base = XEXP (x, 0);
540 offset = 0;
541 if (GET_CODE (base) == CONST
542 && GET_CODE (XEXP (base, 0)) == PLUS
543 && CONST_INT_P (XEXP (XEXP (base, 0), 1)))
544 {
545 offset += INTVAL (XEXP (XEXP (base, 0), 1));
546 base = XEXP (XEXP (base, 0), 0);
547 }
548
549 /* Check whether BASE is suitable for anchors. */
550 if (GET_CODE (base) != SYMBOL_REF
551 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base)
552 || SYMBOL_REF_ANCHOR_P (base)
553 || SYMBOL_REF_BLOCK (base) == NULL
554 || !targetm.use_anchors_for_symbol_p (base))
555 return x;
556
557 /* Decide where BASE is going to be. */
558 place_block_symbol (base);
559
560 /* Get the anchor we need to use. */
561 offset += SYMBOL_REF_BLOCK_OFFSET (base);
562 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset,
563 SYMBOL_REF_TLS_MODEL (base));
564
565 /* Work out the offset from the anchor. */
566 offset -= SYMBOL_REF_BLOCK_OFFSET (base);
567
568 /* If we're going to run a CSE pass, force the anchor into a register.
569 We will then be able to reuse registers for several accesses, if the
570 target costs say that that's worthwhile. */
571 mode = GET_MODE (base);
572 if (!cse_not_expected)
573 base = force_reg (mode, base);
574
575 return replace_equiv_address (x, plus_constant (mode, base, offset));
576}
577
578/* Copy the value or contents of X to a new temp reg and return that reg. */
579
580rtx
581copy_to_reg (rtx x)
582{
583 rtx temp = gen_reg_rtx (GET_MODE (x));
584
585 /* If not an operand, must be an address with PLUS and MULT so
586 do the computation. */
587 if (! general_operand (x, VOIDmode))
588 x = force_operand (x, temp);
589
590 if (x != temp)
591 emit_move_insn (temp, x);
592
593 return temp;
594}
595
596/* Like copy_to_reg but always give the new register mode Pmode
597 in case X is a constant. */
598
599rtx
600copy_addr_to_reg (rtx x)
601{
602 return copy_to_mode_reg (Pmode, x);
603}
604
605/* Like copy_to_reg but always give the new register mode MODE
606 in case X is a constant. */
607
608rtx
609copy_to_mode_reg (machine_mode mode, rtx x)
610{
611 rtx temp = gen_reg_rtx (mode);
612
613 /* If not an operand, must be an address with PLUS and MULT so
614 do the computation. */
615 if (! general_operand (x, VOIDmode))
616 x = force_operand (x, temp);
617
618 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
619 if (x != temp)
620 emit_move_insn (temp, x);
621 return temp;
622}
623
624/* Load X into a register if it is not already one.
625 Use mode MODE for the register.
626 X should be valid for mode MODE, but it may be a constant which
627 is valid for all integer modes; that's why caller must specify MODE.
628
629 The caller must not alter the value in the register we return,
630 since we mark it as a "constant" register. */
631
632rtx
633force_reg (machine_mode mode, rtx x)
634{
635 rtx temp, set;
636 rtx_insn *insn;
637
638 if (REG_P (x))
639 return x;
640
641 if (general_operand (x, mode))
642 {
643 temp = gen_reg_rtx (mode);
644 insn = emit_move_insn (temp, x);
645 }
646 else
647 {
648 temp = force_operand (x, NULL_RTX);
649 if (REG_P (temp))
650 insn = get_last_insn ();
651 else
652 {
653 rtx temp2 = gen_reg_rtx (mode);
654 insn = emit_move_insn (temp2, temp);
655 temp = temp2;
656 }
657 }
658
659 /* Let optimizers know that TEMP's value never changes
660 and that X can be substituted for it. Don't get confused
661 if INSN set something else (such as a SUBREG of TEMP). */
662 if (CONSTANT_P (x)
663 && (set = single_set (insn)) != 0
664 && SET_DEST (set) == temp
665 && ! rtx_equal_p (x, SET_SRC (set)))
666 set_unique_reg_note (insn, REG_EQUAL, x);
667
668 /* Let optimizers know that TEMP is a pointer, and if so, the
669 known alignment of that pointer. */
670 {
671 unsigned align = 0;
672 if (GET_CODE (x) == SYMBOL_REF)
673 {
674 align = BITS_PER_UNIT;
675 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
676 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
677 }
678 else if (GET_CODE (x) == LABEL_REF)
679 align = BITS_PER_UNIT;
680 else if (GET_CODE (x) == CONST
681 && GET_CODE (XEXP (x, 0)) == PLUS
682 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
683 && CONST_INT_P (XEXP (XEXP (x, 0), 1)))
684 {
685 rtx s = XEXP (XEXP (x, 0), 0);
686 rtx c = XEXP (XEXP (x, 0), 1);
687 unsigned sa, ca;
688
689 sa = BITS_PER_UNIT;
690 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
691 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
692
693 if (INTVAL (c) == 0)
694 align = sa;
695 else
696 {
697 ca = ctz_hwi (INTVAL (c)) * BITS_PER_UNIT;
698 align = MIN (sa, ca);
699 }
700 }
701
702 if (align || (MEM_P (x) && MEM_POINTER (x)))
703 mark_reg_pointer (temp, align);
704 }
705
706 return temp;
707}
708
709/* If X is a memory ref, copy its contents to a new temp reg and return
710 that reg. Otherwise, return X. */
711
712rtx
713force_not_mem (rtx x)
714{
715 rtx temp;
716
717 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
718 return x;
719
720 temp = gen_reg_rtx (GET_MODE (x));
721
722 if (MEM_POINTER (x))
723 REG_POINTER (temp) = 1;
724
725 emit_move_insn (temp, x);
726 return temp;
727}
728
729/* Copy X to TARGET (if it's nonzero and a reg)
730 or to a new temp reg and return that reg.
731 MODE is the mode to use for X in case it is a constant. */
732
733rtx
734copy_to_suggested_reg (rtx x, rtx target, machine_mode mode)
735{
736 rtx temp;
737
738 if (target && REG_P (target))
739 temp = target;
740 else
741 temp = gen_reg_rtx (mode);
742
743 emit_move_insn (temp, x);
744 return temp;
745}
746
747/* Return the mode to use to pass or return a scalar of TYPE and MODE.
748 PUNSIGNEDP points to the signedness of the type and may be adjusted
749 to show what signedness to use on extension operations.
750
751 FOR_RETURN is nonzero if the caller is promoting the return value
752 of FNDECL, else it is for promoting args. */
753
754machine_mode
755promote_function_mode (const_tree type, machine_mode mode, int *punsignedp,
756 const_tree funtype, int for_return)
757{
758 /* Called without a type node for a libcall. */
759 if (type == NULL_TREE)
760 {
761 if (INTEGRAL_MODE_P (mode))
762 return targetm.calls.promote_function_mode (NULL_TREE, mode,
763 punsignedp, funtype,
764 for_return);
765 else
766 return mode;
767 }
768
769 switch (TREE_CODE (type))
770 {
771 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
772 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
773 case POINTER_TYPE: case REFERENCE_TYPE:
774 return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype,
775 for_return);
776
777 default:
778 return mode;
779 }
780}
781/* Return the mode to use to store a scalar of TYPE and MODE.
782 PUNSIGNEDP points to the signedness of the type and may be adjusted
783 to show what signedness to use on extension operations. */
784
785machine_mode
786promote_mode (const_tree type ATTRIBUTE_UNUSED, machine_mode mode,
787 int *punsignedp ATTRIBUTE_UNUSED)
788{
789#ifdef PROMOTE_MODE
790 enum tree_code code;
791 int unsignedp;
792 scalar_mode smode;
793#endif
794
795 /* For libcalls this is invoked without TYPE from the backends
796 TARGET_PROMOTE_FUNCTION_MODE hooks. Don't do anything in that
797 case. */
798 if (type == NULL_TREE)
799 return mode;
800
801 /* FIXME: this is the same logic that was there until GCC 4.4, but we
802 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
803 is not defined. The affected targets are M32C, S390, SPARC. */
804#ifdef PROMOTE_MODE
805 code = TREE_CODE (type);
806 unsignedp = *punsignedp;
807
808 switch (code)
809 {
810 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
811 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
812 /* Values of these types always have scalar mode. */
813 smode = as_a <scalar_mode> (mode);
814 PROMOTE_MODE (smode, unsignedp, type);
815 *punsignedp = unsignedp;
816 return smode;
817
818#ifdef POINTERS_EXTEND_UNSIGNED
819 case REFERENCE_TYPE:
820 case POINTER_TYPE:
821 *punsignedp = POINTERS_EXTEND_UNSIGNED;
822 return targetm.addr_space.address_mode
823 (TYPE_ADDR_SPACE (TREE_TYPE (type)));
824#endif
825
826 default:
827 return mode;
828 }
829#else
830 return mode;
831#endif
832}
833
834
835/* Use one of promote_mode or promote_function_mode to find the promoted
836 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
837 of DECL after promotion. */
838
839machine_mode
840promote_decl_mode (const_tree decl, int *punsignedp)
841{
842 tree type = TREE_TYPE (decl);
843 int unsignedp = TYPE_UNSIGNED (type);
844 machine_mode mode = DECL_MODE (decl);
845 machine_mode pmode;
846
847 if (TREE_CODE (decl) == RESULT_DECL && !DECL_BY_REFERENCE (decl))
848 pmode = promote_function_mode (type, mode, &unsignedp,
849 TREE_TYPE (current_function_decl), 1);
850 else if (TREE_CODE (decl) == RESULT_DECL || TREE_CODE (decl) == PARM_DECL)
851 pmode = promote_function_mode (type, mode, &unsignedp,
852 TREE_TYPE (current_function_decl), 2);
853 else
854 pmode = promote_mode (type, mode, &unsignedp);
855
856 if (punsignedp)
857 *punsignedp = unsignedp;
858 return pmode;
859}
860
861/* Return the promoted mode for name. If it is a named SSA_NAME, it
862 is the same as promote_decl_mode. Otherwise, it is the promoted
863 mode of a temp decl of same type as the SSA_NAME, if we had created
864 one. */
865
866machine_mode
867promote_ssa_mode (const_tree name, int *punsignedp)
868{
869 gcc_assert (TREE_CODE (name) == SSA_NAME);
870
871 /* Partitions holding parms and results must be promoted as expected
872 by function.c. */
873 if (SSA_NAME_VAR (name)
874 && (TREE_CODE (SSA_NAME_VAR (name)) == PARM_DECL
875 || TREE_CODE (SSA_NAME_VAR (name)) == RESULT_DECL))
876 {
877 machine_mode mode = promote_decl_mode (SSA_NAME_VAR (name), punsignedp);
878 if (mode != BLKmode)
879 return mode;
880 }
881
882 tree type = TREE_TYPE (name);
883 int unsignedp = TYPE_UNSIGNED (type);
884 machine_mode mode = TYPE_MODE (type);
885
886 /* Bypass TYPE_MODE when it maps vector modes to BLKmode. */
887 if (mode == BLKmode)
888 {
889 gcc_assert (VECTOR_TYPE_P (type));
890 mode = type->type_common.mode;
891 }
892
893 machine_mode pmode = promote_mode (type, mode, &unsignedp);
894 if (punsignedp)
895 *punsignedp = unsignedp;
896
897 return pmode;
898}
899
900
901
902/* Controls the behavior of {anti_,}adjust_stack. */
903static bool suppress_reg_args_size;
904
905/* A helper for adjust_stack and anti_adjust_stack. */
906
907static void
908adjust_stack_1 (rtx adjust, bool anti_p)
909{
910 rtx temp;
911 rtx_insn *insn;
912
913 /* Hereafter anti_p means subtract_p. */
914 if (!STACK_GROWS_DOWNWARD)
915 anti_p = !anti_p;
916
917 temp = expand_binop (Pmode,
918 anti_p ? sub_optab : add_optab,
919 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
920 OPTAB_LIB_WIDEN);
921
922 if (temp != stack_pointer_rtx)
923 insn = emit_move_insn (stack_pointer_rtx, temp);
924 else
925 {
926 insn = get_last_insn ();
927 temp = single_set (insn);
928 gcc_assert (temp != NULL && SET_DEST (temp) == stack_pointer_rtx);
929 }
930
931 if (!suppress_reg_args_size)
932 add_reg_note (insn, REG_ARGS_SIZE, GEN_INT (stack_pointer_delta));
933}
934
935/* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
936 This pops when ADJUST is positive. ADJUST need not be constant. */
937
938void
939adjust_stack (rtx adjust)
940{
941 if (adjust == const0_rtx)
942 return;
943
944 /* We expect all variable sized adjustments to be multiple of
945 PREFERRED_STACK_BOUNDARY. */
946 if (CONST_INT_P (adjust))
947 stack_pointer_delta -= INTVAL (adjust);
948
949 adjust_stack_1 (adjust, false);
950}
951
952/* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
953 This pushes when ADJUST is positive. ADJUST need not be constant. */
954
955void
956anti_adjust_stack (rtx adjust)
957{
958 if (adjust == const0_rtx)
959 return;
960
961 /* We expect all variable sized adjustments to be multiple of
962 PREFERRED_STACK_BOUNDARY. */
963 if (CONST_INT_P (adjust))
964 stack_pointer_delta += INTVAL (adjust);
965
966 adjust_stack_1 (adjust, true);
967}
968
969/* Round the size of a block to be pushed up to the boundary required
970 by this machine. SIZE is the desired size, which need not be constant. */
971
972static rtx
973round_push (rtx size)
974{
975 rtx align_rtx, alignm1_rtx;
976
977 if (!SUPPORTS_STACK_ALIGNMENT
978 || crtl->preferred_stack_boundary == MAX_SUPPORTED_STACK_ALIGNMENT)
979 {
980 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
981
982 if (align == 1)
983 return size;
984
985 if (CONST_INT_P (size))
986 {
987 HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
988
989 if (INTVAL (size) != new_size)
990 size = GEN_INT (new_size);
991 return size;
992 }
993
994 align_rtx = GEN_INT (align);
995 alignm1_rtx = GEN_INT (align - 1);
996 }
997 else
998 {
999 /* If crtl->preferred_stack_boundary might still grow, use
1000 virtual_preferred_stack_boundary_rtx instead. This will be
1001 substituted by the right value in vregs pass and optimized
1002 during combine. */
1003 align_rtx = virtual_preferred_stack_boundary_rtx;
1004 alignm1_rtx = force_operand (plus_constant (Pmode, align_rtx, -1),
1005 NULL_RTX);
1006 }
1007
1008 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1009 but we know it can't. So add ourselves and then do
1010 TRUNC_DIV_EXPR. */
1011 size = expand_binop (Pmode, add_optab, size, alignm1_rtx,
1012 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1013 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, align_rtx,
1014 NULL_RTX, 1);
1015 size = expand_mult (Pmode, size, align_rtx, NULL_RTX, 1);
1016
1017 return size;
1018}
1019
1020/* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
1021 to a previously-created save area. If no save area has been allocated,
1022 this function will allocate one. If a save area is specified, it
1023 must be of the proper mode. */
1024
1025void
1026emit_stack_save (enum save_level save_level, rtx *psave)
1027{
1028 rtx sa = *psave;
1029 /* The default is that we use a move insn and save in a Pmode object. */
1030 rtx_insn *(*fcn) (rtx, rtx) = gen_move_insn;
1031 machine_mode mode = STACK_SAVEAREA_MODE (save_level);
1032
1033 /* See if this machine has anything special to do for this kind of save. */
1034 switch (save_level)
1035 {
1036 case SAVE_BLOCK:
1037 if (targetm.have_save_stack_block ())
1038 fcn = targetm.gen_save_stack_block;
1039 break;
1040 case SAVE_FUNCTION:
1041 if (targetm.have_save_stack_function ())
1042 fcn = targetm.gen_save_stack_function;
1043 break;
1044 case SAVE_NONLOCAL:
1045 if (targetm.have_save_stack_nonlocal ())
1046 fcn = targetm.gen_save_stack_nonlocal;
1047 break;
1048 default:
1049 break;
1050 }
1051
1052 /* If there is no save area and we have to allocate one, do so. Otherwise
1053 verify the save area is the proper mode. */
1054
1055 if (sa == 0)
1056 {
1057 if (mode != VOIDmode)
1058 {
1059 if (save_level == SAVE_NONLOCAL)
1060 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
1061 else
1062 *psave = sa = gen_reg_rtx (mode);
1063 }
1064 }
1065
1066 do_pending_stack_adjust ();
1067 if (sa != 0)
1068 sa = validize_mem (sa);
1069 emit_insn (fcn (sa, stack_pointer_rtx));
1070}
1071
1072/* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1073 area made by emit_stack_save. If it is zero, we have nothing to do. */
1074
1075void
1076emit_stack_restore (enum save_level save_level, rtx sa)
1077{
1078 /* The default is that we use a move insn. */
1079 rtx_insn *(*fcn) (rtx, rtx) = gen_move_insn;
1080
1081 /* If stack_realign_drap, the x86 backend emits a prologue that aligns both
1082 STACK_POINTER and HARD_FRAME_POINTER.
1083 If stack_realign_fp, the x86 backend emits a prologue that aligns only
1084 STACK_POINTER. This renders the HARD_FRAME_POINTER unusable for accessing
1085 aligned variables, which is reflected in ix86_can_eliminate.
1086 We normally still have the realigned STACK_POINTER that we can use.
1087 But if there is a stack restore still present at reload, it can trigger
1088 mark_not_eliminable for the STACK_POINTER, leaving no way to eliminate
1089 FRAME_POINTER into a hard reg.
1090 To prevent this situation, we force need_drap if we emit a stack
1091 restore. */
1092 if (SUPPORTS_STACK_ALIGNMENT)
1093 crtl->need_drap = true;
1094
1095 /* See if this machine has anything special to do for this kind of save. */
1096 switch (save_level)
1097 {
1098 case SAVE_BLOCK:
1099 if (targetm.have_restore_stack_block ())
1100 fcn = targetm.gen_restore_stack_block;
1101 break;
1102 case SAVE_FUNCTION:
1103 if (targetm.have_restore_stack_function ())
1104 fcn = targetm.gen_restore_stack_function;
1105 break;
1106 case SAVE_NONLOCAL:
1107 if (targetm.have_restore_stack_nonlocal ())
1108 fcn = targetm.gen_restore_stack_nonlocal;
1109 break;
1110 default:
1111 break;
1112 }
1113
1114 if (sa != 0)
1115 {
1116 sa = validize_mem (sa);
1117 /* These clobbers prevent the scheduler from moving
1118 references to variable arrays below the code
1119 that deletes (pops) the arrays. */
1120 emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
1121 emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx));
1122 }
1123
1124 discard_pending_stack_adjust ();
1125
1126 emit_insn (fcn (stack_pointer_rtx, sa));
1127}
1128
1129/* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1130 function. This should be called whenever we allocate or deallocate
1131 dynamic stack space. */
1132
1133void
1134update_nonlocal_goto_save_area (void)
1135{
1136 tree t_save;
1137 rtx r_save;
1138
1139 /* The nonlocal_goto_save_area object is an array of N pointers. The
1140 first one is used for the frame pointer save; the rest are sized by
1141 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1142 of the stack save area slots. */
1143 t_save = build4 (ARRAY_REF,
1144 TREE_TYPE (TREE_TYPE (cfun->nonlocal_goto_save_area)),
1145 cfun->nonlocal_goto_save_area,
1146 integer_one_node, NULL_TREE, NULL_TREE);
1147 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1148
1149 emit_stack_save (SAVE_NONLOCAL, &r_save);
1150}
1151
1152/* Record a new stack level for the current function. This should be called
1153 whenever we allocate or deallocate dynamic stack space. */
1154
1155void
1156record_new_stack_level (void)
1157{
1158 /* Record the new stack level for nonlocal gotos. */
1159 if (cfun->nonlocal_goto_save_area)
1160 update_nonlocal_goto_save_area ();
1161
1162 /* Record the new stack level for SJLJ exceptions. */
1163 if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ)
1164 update_sjlj_context ();
1165}
1166
1167/* Return an rtx doing runtime alignment to REQUIRED_ALIGN on TARGET. */
1168static rtx
1169align_dynamic_address (rtx target, unsigned required_align)
1170{
1171 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1172 but we know it can't. So add ourselves and then do
1173 TRUNC_DIV_EXPR. */
1174 target = expand_binop (Pmode, add_optab, target,
1175 gen_int_mode (required_align / BITS_PER_UNIT - 1,
1176 Pmode),
1177 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1178 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1179 gen_int_mode (required_align / BITS_PER_UNIT,
1180 Pmode),
1181 NULL_RTX, 1);
1182 target = expand_mult (Pmode, target,
1183 gen_int_mode (required_align / BITS_PER_UNIT,
1184 Pmode),
1185 NULL_RTX, 1);
1186
1187 return target;
1188}
1189
1190/* Return an rtx through *PSIZE, representing the size of an area of memory to
1191 be dynamically pushed on the stack.
1192
1193 *PSIZE is an rtx representing the size of the area.
1194
1195 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1196 parameter may be zero. If so, a proper value will be extracted
1197 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1198
1199 REQUIRED_ALIGN is the alignment (in bits) required for the region
1200 of memory.
1201
1202 If PSTACK_USAGE_SIZE is not NULL it points to a value that is increased for
1203 the additional size returned. */
1204void
1205get_dynamic_stack_size (rtx *psize, unsigned size_align,
1206 unsigned required_align,
1207 HOST_WIDE_INT *pstack_usage_size)
1208{
1209 unsigned extra = 0;
1210 rtx size = *psize;
1211
1212 /* Ensure the size is in the proper mode. */
1213 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1214 size = convert_to_mode (Pmode, size, 1);
1215
1216 if (CONST_INT_P (size))
1217 {
1218 unsigned HOST_WIDE_INT lsb;
1219
1220 lsb = INTVAL (size);
1221 lsb &= -lsb;
1222
1223 /* Watch out for overflow truncating to "unsigned". */
1224 if (lsb > UINT_MAX / BITS_PER_UNIT)
1225 size_align = 1u << (HOST_BITS_PER_INT - 1);
1226 else
1227 size_align = (unsigned)lsb * BITS_PER_UNIT;
1228 }
1229 else if (size_align < BITS_PER_UNIT)
1230 size_align = BITS_PER_UNIT;
1231
1232 /* We can't attempt to minimize alignment necessary, because we don't
1233 know the final value of preferred_stack_boundary yet while executing
1234 this code. */
1235 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
1236 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1237
1238 /* We will need to ensure that the address we return is aligned to
1239 REQUIRED_ALIGN. At this point in the compilation, we don't always
1240 know the final value of the STACK_DYNAMIC_OFFSET used in function.c
1241 (it might depend on the size of the outgoing parameter lists, for
1242 example), so we must preventively align the value. We leave space
1243 in SIZE for the hole that might result from the alignment operation. */
1244
1245 /* Since the stack is presumed to be aligned before this allocation,
1246 we only need to increase the size of the allocation if the required
1247 alignment is more than the stack alignment. */
1248 if (required_align > STACK_BOUNDARY)
1249 {
1250 extra = (required_align - STACK_BOUNDARY) / BITS_PER_UNIT;
1251 size = plus_constant (Pmode, size, extra);
1252 size = force_operand (size, NULL_RTX);
1253 if (size_align > STACK_BOUNDARY)
1254 size_align = STACK_BOUNDARY;
1255
1256 if (flag_stack_usage_info && pstack_usage_size)
1257 *pstack_usage_size += extra;
1258 }
1259
1260 /* Round the size to a multiple of the required stack alignment.
1261 Since the stack is presumed to be rounded before this allocation,
1262 this will maintain the required alignment.
1263
1264 If the stack grows downward, we could save an insn by subtracting
1265 SIZE from the stack pointer and then aligning the stack pointer.
1266 The problem with this is that the stack pointer may be unaligned
1267 between the execution of the subtraction and alignment insns and
1268 some machines do not allow this. Even on those that do, some
1269 signal handlers malfunction if a signal should occur between those
1270 insns. Since this is an extremely rare event, we have no reliable
1271 way of knowing which systems have this problem. So we avoid even
1272 momentarily mis-aligning the stack. */
1273 if (size_align % MAX_SUPPORTED_STACK_ALIGNMENT != 0)
1274 {
1275 size = round_push (size);
1276
1277 if (flag_stack_usage_info && pstack_usage_size)
1278 {
1279 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
1280 *pstack_usage_size =
1281 (*pstack_usage_size + align - 1) / align * align;
1282 }
1283 }
1284
1285 *psize = size;
1286}
1287
1288/* Return the number of bytes to "protect" on the stack for -fstack-check.
1289
1290 "protect" in the context of -fstack-check means how many bytes we
1291 should always ensure are available on the stack. More importantly
1292 this is how many bytes are skipped when probing the stack.
1293
1294 On some targets we want to reuse the -fstack-check prologue support
1295 to give a degree of protection against stack clashing style attacks.
1296
1297 In that scenario we do not want to skip bytes before probing as that
1298 would render the stack clash protections useless.
1299
1300 So we never use STACK_CHECK_PROTECT directly. Instead we indirect though
1301 this helper which allows us to provide different values for
1302 -fstack-check and -fstack-clash-protection. */
1303HOST_WIDE_INT
1304get_stack_check_protect (void)
1305{
1306 if (flag_stack_clash_protection)
1307 return 0;
1308 return STACK_CHECK_PROTECT;
1309}
1310
1311/* Return an rtx representing the address of an area of memory dynamically
1312 pushed on the stack.
1313
1314 Any required stack pointer alignment is preserved.
1315
1316 SIZE is an rtx representing the size of the area.
1317
1318 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1319 parameter may be zero. If so, a proper value will be extracted
1320 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1321
1322 REQUIRED_ALIGN is the alignment (in bits) required for the region
1323 of memory.
1324
1325 MAX_SIZE is an upper bound for SIZE, if SIZE is not constant, or -1 if
1326 no such upper bound is known.
1327
1328 If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
1329 stack space allocated by the generated code cannot be added with itself
1330 in the course of the execution of the function. It is always safe to
1331 pass FALSE here and the following criterion is sufficient in order to
1332 pass TRUE: every path in the CFG that starts at the allocation point and
1333 loops to it executes the associated deallocation code. */
1334
1335rtx
1336allocate_dynamic_stack_space (rtx size, unsigned size_align,
1337 unsigned required_align,
1338 HOST_WIDE_INT max_size,
1339 bool cannot_accumulate)
1340{
1341 HOST_WIDE_INT stack_usage_size = -1;
1342 rtx_code_label *final_label;
1343 rtx final_target, target;
1344
1345 /* If we're asking for zero bytes, it doesn't matter what we point
1346 to since we can't dereference it. But return a reasonable
1347 address anyway. */
1348 if (size == const0_rtx)
1349 return virtual_stack_dynamic_rtx;
1350
1351 /* Otherwise, show we're calling alloca or equivalent. */
1352 cfun->calls_alloca = 1;
1353
1354 /* If stack usage info is requested, look into the size we are passed.
1355 We need to do so this early to avoid the obfuscation that may be
1356 introduced later by the various alignment operations. */
1357 if (flag_stack_usage_info)
1358 {
1359 if (CONST_INT_P (size))
1360 stack_usage_size = INTVAL (size);
1361 else if (REG_P (size))
1362 {
1363 /* Look into the last emitted insn and see if we can deduce
1364 something for the register. */
1365 rtx_insn *insn;
1366 rtx set, note;
1367 insn = get_last_insn ();
1368 if ((set = single_set (insn)) && rtx_equal_p (SET_DEST (set), size))
1369 {
1370 if (CONST_INT_P (SET_SRC (set)))
1371 stack_usage_size = INTVAL (SET_SRC (set));
1372 else if ((note = find_reg_equal_equiv_note (insn))
1373 && CONST_INT_P (XEXP (note, 0)))
1374 stack_usage_size = INTVAL (XEXP (note, 0));
1375 }
1376 }
1377
1378 /* If the size is not constant, try the maximum size. */
1379 if (stack_usage_size < 0)
1380 stack_usage_size = max_size;
1381
1382 /* If the size is still not constant, we can't say anything. */
1383 if (stack_usage_size < 0)
1384 {
1385 current_function_has_unbounded_dynamic_stack_size = 1;
1386 stack_usage_size = 0;
1387 }
1388 }
1389
1390 get_dynamic_stack_size (&size, size_align, required_align, &stack_usage_size);
1391
1392 target = gen_reg_rtx (Pmode);
1393
1394 /* The size is supposed to be fully adjusted at this point so record it
1395 if stack usage info is requested. */
1396 if (flag_stack_usage_info)
1397 {
1398 current_function_dynamic_stack_size += stack_usage_size;
1399
1400 /* ??? This is gross but the only safe stance in the absence
1401 of stack usage oriented flow analysis. */
1402 if (!cannot_accumulate)
1403 current_function_has_unbounded_dynamic_stack_size = 1;
1404 }
1405
1406 do_pending_stack_adjust ();
1407
1408 final_label = NULL;
1409 final_target = NULL_RTX;
1410
1411 /* If we are splitting the stack, we need to ask the backend whether
1412 there is enough room on the current stack. If there isn't, or if
1413 the backend doesn't know how to tell is, then we need to call a
1414 function to allocate memory in some other way. This memory will
1415 be released when we release the current stack segment. The
1416 effect is that stack allocation becomes less efficient, but at
1417 least it doesn't cause a stack overflow. */
1418 if (flag_split_stack)
1419 {
1420 rtx_code_label *available_label;
1421 rtx ask, space, func;
1422
1423 available_label = NULL;
1424
1425 if (targetm.have_split_stack_space_check ())
1426 {
1427 available_label = gen_label_rtx ();
1428
1429 /* This instruction will branch to AVAILABLE_LABEL if there
1430 are SIZE bytes available on the stack. */
1431 emit_insn (targetm.gen_split_stack_space_check
1432 (size, available_label));
1433 }
1434
1435 /* The __morestack_allocate_stack_space function will allocate
1436 memory using malloc. If the alignment of the memory returned
1437 by malloc does not meet REQUIRED_ALIGN, we increase SIZE to
1438 make sure we allocate enough space. */
1439 if (MALLOC_ABI_ALIGNMENT >= required_align)
1440 ask = size;
1441 else
1442 ask = expand_binop (Pmode, add_optab, size,
1443 gen_int_mode (required_align / BITS_PER_UNIT - 1,
1444 Pmode),
1445 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1446
1447 func = init_one_libfunc ("__morestack_allocate_stack_space");
1448
1449 space = emit_library_call_value (func, target, LCT_NORMAL, Pmode,
1450 ask, Pmode);
1451
1452 if (available_label == NULL_RTX)
1453 return space;
1454
1455 final_target = gen_reg_rtx (Pmode);
1456
1457 emit_move_insn (final_target, space);
1458
1459 final_label = gen_label_rtx ();
1460 emit_jump (final_label);
1461
1462 emit_label (available_label);
1463 }
1464
1465 /* We ought to be called always on the toplevel and stack ought to be aligned
1466 properly. */
1467 gcc_assert (!(stack_pointer_delta
1468 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)));
1469
1470 /* If needed, check that we have the required amount of stack. Take into
1471 account what has already been checked. */
1472 if (STACK_CHECK_MOVING_SP)
1473 ;
1474 else if (flag_stack_check == GENERIC_STACK_CHECK)
1475 probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE,
1476 size);
1477 else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
1478 probe_stack_range (get_stack_check_protect (), size);
1479
1480 /* Don't let anti_adjust_stack emit notes. */
1481 suppress_reg_args_size = true;
1482
1483 /* Perform the required allocation from the stack. Some systems do
1484 this differently than simply incrementing/decrementing from the
1485 stack pointer, such as acquiring the space by calling malloc(). */
1486 if (targetm.have_allocate_stack ())
1487 {
1488 struct expand_operand ops[2];
1489 /* We don't have to check against the predicate for operand 0 since
1490 TARGET is known to be a pseudo of the proper mode, which must
1491 be valid for the operand. */
1492 create_fixed_operand (&ops[0], target);
1493 create_convert_operand_to (&ops[1], size, STACK_SIZE_MODE, true);
1494 expand_insn (targetm.code_for_allocate_stack, 2, ops);
1495 }
1496 else
1497 {
1498 int saved_stack_pointer_delta;
1499
1500 if (!STACK_GROWS_DOWNWARD)
1501 emit_move_insn (target, virtual_stack_dynamic_rtx);
1502
1503 /* Check stack bounds if necessary. */
1504 if (crtl->limit_stack)
1505 {
1506 rtx available;
1507 rtx_code_label *space_available = gen_label_rtx ();
1508 if (STACK_GROWS_DOWNWARD)
1509 available = expand_binop (Pmode, sub_optab,
1510 stack_pointer_rtx, stack_limit_rtx,
1511 NULL_RTX, 1, OPTAB_WIDEN);
1512 else
1513 available = expand_binop (Pmode, sub_optab,
1514 stack_limit_rtx, stack_pointer_rtx,
1515 NULL_RTX, 1, OPTAB_WIDEN);
1516
1517 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1518 space_available);
1519 if (targetm.have_trap ())
1520 emit_insn (targetm.gen_trap ());
1521 else
1522 error ("stack limits not supported on this target");
1523 emit_barrier ();
1524 emit_label (space_available);
1525 }
1526
1527 saved_stack_pointer_delta = stack_pointer_delta;
1528
1529 if (flag_stack_check && STACK_CHECK_MOVING_SP)
1530 anti_adjust_stack_and_probe (size, false);
1531 else if (flag_stack_clash_protection)
1532 anti_adjust_stack_and_probe_stack_clash (size);
1533 else
1534 anti_adjust_stack (size);
1535
1536 /* Even if size is constant, don't modify stack_pointer_delta.
1537 The constant size alloca should preserve
1538 crtl->preferred_stack_boundary alignment. */
1539 stack_pointer_delta = saved_stack_pointer_delta;
1540
1541 if (STACK_GROWS_DOWNWARD)
1542 emit_move_insn (target, virtual_stack_dynamic_rtx);
1543 }
1544
1545 suppress_reg_args_size = false;
1546
1547 /* Finish up the split stack handling. */
1548 if (final_label != NULL_RTX)
1549 {
1550 gcc_assert (flag_split_stack);
1551 emit_move_insn (final_target, target);
1552 emit_label (final_label);
1553 target = final_target;
1554 }
1555
1556 target = align_dynamic_address (target, required_align);
1557
1558 /* Now that we've committed to a return value, mark its alignment. */
1559 mark_reg_pointer (target, required_align);
1560
1561 /* Record the new stack level. */
1562 record_new_stack_level ();
1563
1564 return target;
1565}
1566
1567/* Return an rtx representing the address of an area of memory already
1568 statically pushed onto the stack in the virtual stack vars area. (It is
1569 assumed that the area is allocated in the function prologue.)
1570
1571 Any required stack pointer alignment is preserved.
1572
1573 OFFSET is the offset of the area into the virtual stack vars area.
1574
1575 REQUIRED_ALIGN is the alignment (in bits) required for the region
1576 of memory. */
1577
1578rtx
1579get_dynamic_stack_base (HOST_WIDE_INT offset, unsigned required_align)
1580{
1581 rtx target;
1582
1583 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
1584 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1585
1586 target = gen_reg_rtx (Pmode);
1587 emit_move_insn (target, virtual_stack_vars_rtx);
1588 target = expand_binop (Pmode, add_optab, target,
1589 gen_int_mode (offset, Pmode),
1590 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1591 target = align_dynamic_address (target, required_align);
1592
1593 /* Now that we've committed to a return value, mark its alignment. */
1594 mark_reg_pointer (target, required_align);
1595
1596 return target;
1597}
1598
1599/* A front end may want to override GCC's stack checking by providing a
1600 run-time routine to call to check the stack, so provide a mechanism for
1601 calling that routine. */
1602
1603static GTY(()) rtx stack_check_libfunc;
1604
1605void
1606set_stack_check_libfunc (const char *libfunc_name)
1607{
1608 gcc_assert (stack_check_libfunc == NULL_RTX);
1609 stack_check_libfunc = gen_rtx_SYMBOL_REF (Pmode, libfunc_name);
1610}
1611
1612/* Emit one stack probe at ADDRESS, an address within the stack. */
1613
1614void
1615emit_stack_probe (rtx address)
1616{
1617 if (targetm.have_probe_stack_address ())
1618 emit_insn (targetm.gen_probe_stack_address (address));
1619 else
1620 {
1621 rtx memref = gen_rtx_MEM (word_mode, address);
1622
1623 MEM_VOLATILE_P (memref) = 1;
1624
1625 /* See if we have an insn to probe the stack. */
1626 if (targetm.have_probe_stack ())
1627 emit_insn (targetm.gen_probe_stack (memref));
1628 else
1629 emit_move_insn (memref, const0_rtx);
1630 }
1631}
1632
1633/* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1634 FIRST is a constant and size is a Pmode RTX. These are offsets from
1635 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
1636 or subtract them from the stack pointer. */
1637
1638#define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
1639
1640#if STACK_GROWS_DOWNWARD
1641#define STACK_GROW_OP MINUS
1642#define STACK_GROW_OPTAB sub_optab
1643#define STACK_GROW_OFF(off) -(off)
1644#else
1645#define STACK_GROW_OP PLUS
1646#define STACK_GROW_OPTAB add_optab
1647#define STACK_GROW_OFF(off) (off)
1648#endif
1649
1650void
1651probe_stack_range (HOST_WIDE_INT first, rtx size)
1652{
1653 /* First ensure SIZE is Pmode. */
1654 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1655 size = convert_to_mode (Pmode, size, 1);
1656
1657 /* Next see if we have a function to check the stack. */
1658 if (stack_check_libfunc)
1659 {
1660 rtx addr = memory_address (Pmode,
1661 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1662 stack_pointer_rtx,
1663 plus_constant (Pmode,
1664 size, first)));
1665 emit_library_call (stack_check_libfunc, LCT_THROW, VOIDmode,
1666 addr, Pmode);
1667 }
1668
1669 /* Next see if we have an insn to check the stack. */
1670 else if (targetm.have_check_stack ())
1671 {
1672 struct expand_operand ops[1];
1673 rtx addr = memory_address (Pmode,
1674 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1675 stack_pointer_rtx,
1676 plus_constant (Pmode,
1677 size, first)));
1678 bool success;
1679 create_input_operand (&ops[0], addr, Pmode);
1680 success = maybe_expand_insn (targetm.code_for_check_stack, 1, ops);
1681 gcc_assert (success);
1682 }
1683
1684 /* Otherwise we have to generate explicit probes. If we have a constant
1685 small number of them to generate, that's the easy case. */
1686 else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
1687 {
1688 HOST_WIDE_INT isize = INTVAL (size), i;
1689 rtx addr;
1690
1691 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
1692 it exceeds SIZE. If only one probe is needed, this will not
1693 generate any code. Then probe at FIRST + SIZE. */
1694 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
1695 {
1696 addr = memory_address (Pmode,
1697 plus_constant (Pmode, stack_pointer_rtx,
1698 STACK_GROW_OFF (first + i)));
1699 emit_stack_probe (addr);
1700 }
1701
1702 addr = memory_address (Pmode,
1703 plus_constant (Pmode, stack_pointer_rtx,
1704 STACK_GROW_OFF (first + isize)));
1705 emit_stack_probe (addr);
1706 }
1707
1708 /* In the variable case, do the same as above, but in a loop. Note that we
1709 must be extra careful with variables wrapping around because we might be
1710 at the very top (or the very bottom) of the address space and we have to
1711 be able to handle this case properly; in particular, we use an equality
1712 test for the loop condition. */
1713 else
1714 {
1715 rtx rounded_size, rounded_size_op, test_addr, last_addr, temp;
1716 rtx_code_label *loop_lab = gen_label_rtx ();
1717 rtx_code_label *end_lab = gen_label_rtx ();
1718
1719 /* Step 1: round SIZE to the previous multiple of the interval. */
1720
1721 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1722 rounded_size
1723 = simplify_gen_binary (AND, Pmode, size,
1724 gen_int_mode (-PROBE_INTERVAL, Pmode));
1725 rounded_size_op = force_operand (rounded_size, NULL_RTX);
1726
1727
1728 /* Step 2: compute initial and final value of the loop counter. */
1729
1730 /* TEST_ADDR = SP + FIRST. */
1731 test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1732 stack_pointer_rtx,
1733 gen_int_mode (first, Pmode)),
1734 NULL_RTX);
1735
1736 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
1737 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1738 test_addr,
1739 rounded_size_op), NULL_RTX);
1740
1741
1742 /* Step 3: the loop
1743
1744 while (TEST_ADDR != LAST_ADDR)
1745 {
1746 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
1747 probe at TEST_ADDR
1748 }
1749
1750 probes at FIRST + N * PROBE_INTERVAL for values of N from 1
1751 until it is equal to ROUNDED_SIZE. */
1752
1753 emit_label (loop_lab);
1754
1755 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
1756 emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1,
1757 end_lab);
1758
1759 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
1760 temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr,
1761 gen_int_mode (PROBE_INTERVAL, Pmode), test_addr,
1762 1, OPTAB_WIDEN);
1763
1764 gcc_assert (temp == test_addr);
1765
1766 /* Probe at TEST_ADDR. */
1767 emit_stack_probe (test_addr);
1768
1769 emit_jump (loop_lab);
1770
1771 emit_label (end_lab);
1772
1773
1774 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
1775 that SIZE is equal to ROUNDED_SIZE. */
1776
1777 /* TEMP = SIZE - ROUNDED_SIZE. */
1778 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
1779 if (temp != const0_rtx)
1780 {
1781 rtx addr;
1782
1783 if (CONST_INT_P (temp))
1784 {
1785 /* Use [base + disp} addressing mode if supported. */
1786 HOST_WIDE_INT offset = INTVAL (temp);
1787 addr = memory_address (Pmode,
1788 plus_constant (Pmode, last_addr,
1789 STACK_GROW_OFF (offset)));
1790 }
1791 else
1792 {
1793 /* Manual CSE if the difference is not known at compile-time. */
1794 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
1795 addr = memory_address (Pmode,
1796 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1797 last_addr, temp));
1798 }
1799
1800 emit_stack_probe (addr);
1801 }
1802 }
1803
1804 /* Make sure nothing is scheduled before we are done. */
1805 emit_insn (gen_blockage ());
1806}
1807
1808/* Compute parameters for stack clash probing a dynamic stack
1809 allocation of SIZE bytes.
1810
1811 We compute ROUNDED_SIZE, LAST_ADDR, RESIDUAL and PROBE_INTERVAL.
1812
1813 Additionally we conditionally dump the type of probing that will
1814 be needed given the values computed. */
1815
1816void
1817compute_stack_clash_protection_loop_data (rtx *rounded_size, rtx *last_addr,
1818 rtx *residual,
1819 HOST_WIDE_INT *probe_interval,
1820 rtx size)
1821{
1822 /* Round SIZE down to STACK_CLASH_PROTECTION_PROBE_INTERVAL */
1823 *probe_interval
1824 = 1 << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL);
1825 *rounded_size = simplify_gen_binary (AND, Pmode, size,
1826 GEN_INT (-*probe_interval));
1827
1828 /* Compute the value of the stack pointer for the last iteration.
1829 It's just SP + ROUNDED_SIZE. */
1830 rtx rounded_size_op = force_operand (*rounded_size, NULL_RTX);
1831 *last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1832 stack_pointer_rtx,
1833 rounded_size_op),
1834 NULL_RTX);
1835
1836 /* Compute any residuals not allocated by the loop above. Residuals
1837 are just the ROUNDED_SIZE - SIZE. */
1838 *residual = simplify_gen_binary (MINUS, Pmode, size, *rounded_size);
1839
1840 /* Dump key information to make writing tests easy. */
1841 if (dump_file)
1842 {
1843 if (*rounded_size == CONST0_RTX (Pmode))
1844 fprintf (dump_file,
1845 "Stack clash skipped dynamic allocation and probing loop.\n");
1846 else if (CONST_INT_P (*rounded_size)
1847 && INTVAL (*rounded_size) <= 4 * *probe_interval)
1848 fprintf (dump_file,
1849 "Stack clash dynamic allocation and probing inline.\n");
1850 else if (CONST_INT_P (*rounded_size))
1851 fprintf (dump_file,
1852 "Stack clash dynamic allocation and probing in "
1853 "rotated loop.\n");
1854 else
1855 fprintf (dump_file,
1856 "Stack clash dynamic allocation and probing in loop.\n");
1857
1858 if (*residual != CONST0_RTX (Pmode))
1859 fprintf (dump_file,
1860 "Stack clash dynamic allocation and probing residuals.\n");
1861 else
1862 fprintf (dump_file,
1863 "Stack clash skipped dynamic allocation and "
1864 "probing residuals.\n");
1865 }
1866}
1867
1868/* Emit the start of an allocate/probe loop for stack
1869 clash protection.
1870
1871 LOOP_LAB and END_LAB are returned for use when we emit the
1872 end of the loop.
1873
1874 LAST addr is the value for SP which stops the loop. */
1875void
1876emit_stack_clash_protection_probe_loop_start (rtx *loop_lab,
1877 rtx *end_lab,
1878 rtx last_addr,
1879 bool rotated)
1880{
1881 /* Essentially we want to emit any setup code, the top of loop
1882 label and the comparison at the top of the loop. */
1883 *loop_lab = gen_label_rtx ();
1884 *end_lab = gen_label_rtx ();
1885
1886 emit_label (*loop_lab);
1887 if (!rotated)
1888 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
1889 Pmode, 1, *end_lab);
1890}
1891
1892/* Emit the end of a stack clash probing loop.
1893
1894 This consists of just the jump back to LOOP_LAB and
1895 emitting END_LOOP after the loop. */
1896
1897void
1898emit_stack_clash_protection_probe_loop_end (rtx loop_lab, rtx end_loop,
1899 rtx last_addr, bool rotated)
1900{
1901 if (rotated)
1902 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, NE, NULL_RTX,
1903 Pmode, 1, loop_lab);
1904 else
1905 emit_jump (loop_lab);
1906
1907 emit_label (end_loop);
1908
1909}
1910
1911/* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
1912 while probing it. This pushes when SIZE is positive. SIZE need not
1913 be constant.
1914
1915 This is subtly different than anti_adjust_stack_and_probe to try and
1916 prevent stack-clash attacks
1917
1918 1. It must assume no knowledge of the probing state, any allocation
1919 must probe.
1920
1921 Consider the case of a 1 byte alloca in a loop. If the sum of the
1922 allocations is large, then this could be used to jump the guard if
1923 probes were not emitted.
1924
1925 2. It never skips probes, whereas anti_adjust_stack_and_probe will
1926 skip probes on the first couple PROBE_INTERVALs on the assumption
1927 they're done elsewhere.
1928
1929 3. It only allocates and probes SIZE bytes, it does not need to
1930 allocate/probe beyond that because this probing style does not
1931 guarantee signal handling capability if the guard is hit. */
1932
1933static void
1934anti_adjust_stack_and_probe_stack_clash (rtx size)
1935{
1936 /* First ensure SIZE is Pmode. */
1937 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1938 size = convert_to_mode (Pmode, size, 1);
1939
1940 /* We can get here with a constant size on some targets. */
1941 rtx rounded_size, last_addr, residual;
1942 HOST_WIDE_INT probe_interval;
1943 compute_stack_clash_protection_loop_data (&rounded_size, &last_addr,
1944 &residual, &probe_interval, size);
1945
1946 if (rounded_size != CONST0_RTX (Pmode))
1947 {
1948 if (CONST_INT_P (rounded_size)
1949 && INTVAL (rounded_size) <= 4 * probe_interval)
1950 {
1951 for (HOST_WIDE_INT i = 0;
1952 i < INTVAL (rounded_size);
1953 i += probe_interval)
1954 {
1955 anti_adjust_stack (GEN_INT (probe_interval));
1956
1957 /* The prologue does not probe residuals. Thus the offset
1958 here to probe just beyond what the prologue had already
1959 allocated. */
1960 emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
1961 (probe_interval
1962 - GET_MODE_SIZE (word_mode))));
1963 emit_insn (gen_blockage ());
1964 }
1965 }
1966 else
1967 {
1968 rtx loop_lab, end_loop;
1969 bool rotate_loop = CONST_INT_P (rounded_size);
1970 emit_stack_clash_protection_probe_loop_start (&loop_lab, &end_loop,
1971 last_addr, rotate_loop);
1972
1973 anti_adjust_stack (GEN_INT (probe_interval));
1974
1975 /* The prologue does not probe residuals. Thus the offset here
1976 to probe just beyond what the prologue had already allocated. */
1977 emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
1978 (probe_interval
1979 - GET_MODE_SIZE (word_mode))));
1980
1981 emit_stack_clash_protection_probe_loop_end (loop_lab, end_loop,
1982 last_addr, rotate_loop);
1983 emit_insn (gen_blockage ());
1984 }
1985 }
1986
1987 if (residual != CONST0_RTX (Pmode))
1988 {
1989 rtx x = force_reg (Pmode, plus_constant (Pmode, residual,
1990 -GET_MODE_SIZE (word_mode)));
1991 anti_adjust_stack (residual);
1992 emit_stack_probe (gen_rtx_PLUS (Pmode, stack_pointer_rtx, x));
1993 emit_insn (gen_blockage ());
1994 }
1995
1996 /* Some targets make optimistic assumptions in their prologues about
1997 how the caller may have probed the stack. Make sure we honor
1998 those assumptions when needed. */
1999 if (size != CONST0_RTX (Pmode)
2000 && targetm.stack_clash_protection_final_dynamic_probe (residual))
2001 {
2002 /* SIZE could be zero at runtime and in that case *sp could hold
2003 live data. Furthermore, we don't want to probe into the red
2004 zone.
2005
2006 Go ahead and just guard a probe at *sp on SIZE != 0 at runtime
2007 if SIZE is not a compile time constant. */
2008
2009 /* Ideally we would just probe at *sp. However, if SIZE is not
2010 a compile-time constant, but is zero at runtime, then *sp
2011 might hold live data. So probe at *sp if we know that
2012 an allocation was made, otherwise probe into the red zone
2013 which is obviously undesirable. */
2014 if (CONST_INT_P (size))
2015 {
2016 emit_stack_probe (stack_pointer_rtx);
2017 emit_insn (gen_blockage ());
2018 }
2019 else
2020 {
2021 rtx label = gen_label_rtx ();
2022 emit_cmp_and_jump_insns (size, CONST0_RTX (GET_MODE (size)),
2023 EQ, NULL_RTX, Pmode, 1, label);
2024 emit_stack_probe (stack_pointer_rtx);
2025 emit_insn (gen_blockage ());
2026 emit_label (label);
2027 }
2028 }
2029}
2030
2031
2032/* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
2033 while probing it. This pushes when SIZE is positive. SIZE need not
2034 be constant. If ADJUST_BACK is true, adjust back the stack pointer
2035 by plus SIZE at the end. */
2036
2037void
2038anti_adjust_stack_and_probe (rtx size, bool adjust_back)
2039{
2040 /* We skip the probe for the first interval + a small dope of 4 words and
2041 probe that many bytes past the specified size to maintain a protection
2042 area at the botton of the stack. */
2043 const int dope = 4 * UNITS_PER_WORD;
2044
2045 /* First ensure SIZE is Pmode. */
2046 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
2047 size = convert_to_mode (Pmode, size, 1);
2048
2049 /* If we have a constant small number of probes to generate, that's the
2050 easy case. */
2051 if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
2052 {
2053 HOST_WIDE_INT isize = INTVAL (size), i;
2054 bool first_probe = true;
2055
2056 /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
2057 values of N from 1 until it exceeds SIZE. If only one probe is
2058 needed, this will not generate any code. Then adjust and probe
2059 to PROBE_INTERVAL + SIZE. */
2060 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
2061 {
2062 if (first_probe)
2063 {
2064 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope));
2065 first_probe = false;
2066 }
2067 else
2068 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
2069 emit_stack_probe (stack_pointer_rtx);
2070 }
2071
2072 if (first_probe)
2073 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
2074 else
2075 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL - i));
2076 emit_stack_probe (stack_pointer_rtx);
2077 }
2078
2079 /* In the variable case, do the same as above, but in a loop. Note that we
2080 must be extra careful with variables wrapping around because we might be
2081 at the very top (or the very bottom) of the address space and we have to
2082 be able to handle this case properly; in particular, we use an equality
2083 test for the loop condition. */
2084 else
2085 {
2086 rtx rounded_size, rounded_size_op, last_addr, temp;
2087 rtx_code_label *loop_lab = gen_label_rtx ();
2088 rtx_code_label *end_lab = gen_label_rtx ();
2089
2090
2091 /* Step 1: round SIZE to the previous multiple of the interval. */
2092
2093 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
2094 rounded_size
2095 = simplify_gen_binary (AND, Pmode, size,
2096 gen_int_mode (-PROBE_INTERVAL, Pmode));
2097 rounded_size_op = force_operand (rounded_size, NULL_RTX);
2098
2099
2100 /* Step 2: compute initial and final value of the loop counter. */
2101
2102 /* SP = SP_0 + PROBE_INTERVAL. */
2103 anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
2104
2105 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
2106 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
2107 stack_pointer_rtx,
2108 rounded_size_op), NULL_RTX);
2109
2110
2111 /* Step 3: the loop
2112
2113 while (SP != LAST_ADDR)
2114 {
2115 SP = SP + PROBE_INTERVAL
2116 probe at SP
2117 }
2118
2119 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
2120 values of N from 1 until it is equal to ROUNDED_SIZE. */
2121
2122 emit_label (loop_lab);
2123
2124 /* Jump to END_LAB if SP == LAST_ADDR. */
2125 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
2126 Pmode, 1, end_lab);
2127
2128 /* SP = SP + PROBE_INTERVAL and probe at SP. */
2129 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
2130 emit_stack_probe (stack_pointer_rtx);
2131
2132 emit_jump (loop_lab);
2133
2134 emit_label (end_lab);
2135
2136
2137 /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
2138 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
2139
2140 /* TEMP = SIZE - ROUNDED_SIZE. */
2141 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
2142 if (temp != const0_rtx)
2143 {
2144 /* Manual CSE if the difference is not known at compile-time. */
2145 if (GET_CODE (temp) != CONST_INT)
2146 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
2147 anti_adjust_stack (temp);
2148 emit_stack_probe (stack_pointer_rtx);
2149 }
2150 }
2151
2152 /* Adjust back and account for the additional first interval. */
2153 if (adjust_back)
2154 adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
2155 else
2156 adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
2157}
2158
2159/* Return an rtx representing the register or memory location
2160 in which a scalar value of data type VALTYPE
2161 was returned by a function call to function FUNC.
2162 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
2163 function is known, otherwise 0.
2164 OUTGOING is 1 if on a machine with register windows this function
2165 should return the register in which the function will put its result
2166 and 0 otherwise. */
2167
2168rtx
2169hard_function_value (const_tree valtype, const_tree func, const_tree fntype,
2170 int outgoing ATTRIBUTE_UNUSED)
2171{
2172 rtx val;
2173
2174 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
2175
2176 if (REG_P (val)
2177 && GET_MODE (val) == BLKmode)
2178 {
2179 unsigned HOST_WIDE_INT bytes = arg_int_size_in_bytes (valtype);
2180 opt_scalar_int_mode tmpmode;
2181
2182 /* int_size_in_bytes can return -1. We don't need a check here
2183 since the value of bytes will then be large enough that no
2184 mode will match anyway. */
2185
2186 FOR_EACH_MODE_IN_CLASS (tmpmode, MODE_INT)
2187 {
2188 /* Have we found a large enough mode? */
2189 if (GET_MODE_SIZE (tmpmode.require ()) >= bytes)
2190 break;
2191 }
2192
2193 PUT_MODE (val, tmpmode.require ());
2194 }
2195 return val;
2196}
2197
2198/* Return an rtx representing the register or memory location
2199 in which a scalar value of mode MODE was returned by a library call. */
2200
2201rtx
2202hard_libcall_value (machine_mode mode, rtx fun)
2203{
2204 return targetm.calls.libcall_value (mode, fun);
2205}
2206
2207/* Look up the tree code for a given rtx code
2208 to provide the arithmetic operation for real_arithmetic.
2209 The function returns an int because the caller may not know
2210 what `enum tree_code' means. */
2211
2212int
2213rtx_to_tree_code (enum rtx_code code)
2214{
2215 enum tree_code tcode;
2216
2217 switch (code)
2218 {
2219 case PLUS:
2220 tcode = PLUS_EXPR;
2221 break;
2222 case MINUS:
2223 tcode = MINUS_EXPR;
2224 break;
2225 case MULT:
2226 tcode = MULT_EXPR;
2227 break;
2228 case DIV:
2229 tcode = RDIV_EXPR;
2230 break;
2231 case SMIN:
2232 tcode = MIN_EXPR;
2233 break;
2234 case SMAX:
2235 tcode = MAX_EXPR;
2236 break;
2237 default:
2238 tcode = LAST_AND_UNUSED_TREE_CODE;
2239 break;
2240 }
2241 return ((int) tcode);
2242}
2243
2244#include "gt-explow.h"
2245