Disable tests for strdup/strndup on __hpux__
[official-gcc.git] / gcc / explow.cc
blob8e5f6b8e68044887218a4323ff431e271a7e326d
1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987-2024 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
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 "optabs.h"
31 #include "expmed.h"
32 #include "profile-count.h"
33 #include "emit-rtl.h"
34 #include "recog.h"
35 #include "diagnostic-core.h"
36 #include "stor-layout.h"
37 #include "langhooks.h"
38 #include "except.h"
39 #include "dojump.h"
40 #include "explow.h"
41 #include "expr.h"
42 #include "stringpool.h"
43 #include "common/common-target.h"
44 #include "output.h"
46 static rtx break_out_memory_refs (rtx);
49 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
51 HOST_WIDE_INT
52 trunc_int_for_mode (HOST_WIDE_INT c, machine_mode mode)
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);
58 /* You want to truncate to a _what_? */
59 gcc_assert (SCALAR_INT_MODE_P (mode));
61 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
62 if (smode == BImode)
63 return c & 1 ? STORE_FLAG_VALUE : 0;
65 /* Sign-extend for the requested mode. */
67 if (width < HOST_BITS_PER_WIDE_INT)
69 HOST_WIDE_INT sign = 1;
70 sign <<= width - 1;
71 c &= (sign << 1) - 1;
72 c ^= sign;
73 c -= sign;
76 return c;
79 /* Likewise for polynomial values, using the sign-extended representation
80 for each individual coefficient. */
82 poly_int64
83 trunc_int_for_mode (poly_int64 x, machine_mode mode)
85 for (unsigned int i = 0; i < NUM_POLY_INT_COEFFS; ++i)
86 x.coeffs[i] = trunc_int_for_mode (x.coeffs[i], mode);
87 return x;
90 /* Return an rtx for the sum of X and the integer C, given that X has
91 mode MODE. INPLACE is true if X can be modified inplace or false
92 if it must be treated as immutable. */
94 rtx
95 plus_constant (machine_mode mode, rtx x, poly_int64 c, bool inplace)
97 RTX_CODE code;
98 rtx y;
99 rtx tem;
100 int all_constant = 0;
102 gcc_assert (GET_MODE (x) == VOIDmode || GET_MODE (x) == mode);
104 if (known_eq (c, 0))
105 return x;
107 restart:
109 code = GET_CODE (x);
110 y = x;
112 switch (code)
114 CASE_CONST_SCALAR_INT:
115 return immed_wide_int_const (wi::add (rtx_mode_t (x, mode), c), mode);
116 case MEM:
117 /* If this is a reference to the constant pool, try replacing it with
118 a reference to a new constant. If the resulting address isn't
119 valid, don't return it because we have no way to validize it. */
120 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
121 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
123 rtx cst = get_pool_constant (XEXP (x, 0));
125 if (GET_CODE (cst) == CONST_VECTOR
126 && GET_MODE_INNER (GET_MODE (cst)) == mode)
128 cst = gen_lowpart (mode, cst);
129 gcc_assert (cst);
131 else if (GET_MODE (cst) == VOIDmode
132 && get_pool_mode (XEXP (x, 0)) != mode)
133 break;
134 if (GET_MODE (cst) == VOIDmode || GET_MODE (cst) == mode)
136 tem = plus_constant (mode, cst, c);
137 tem = force_const_mem (GET_MODE (x), tem);
138 /* Targets may disallow some constants in the constant pool, thus
139 force_const_mem may return NULL_RTX. */
140 if (tem && memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
141 return tem;
144 break;
146 case CONST:
147 /* If adding to something entirely constant, set a flag
148 so that we can add a CONST around the result. */
149 if (inplace && shared_const_p (x))
150 inplace = false;
151 x = XEXP (x, 0);
152 all_constant = 1;
153 goto restart;
155 case SYMBOL_REF:
156 case LABEL_REF:
157 all_constant = 1;
158 break;
160 case PLUS:
161 /* The interesting case is adding the integer to a sum. Look
162 for constant term in the sum and combine with C. For an
163 integer constant term or a constant term that is not an
164 explicit integer, we combine or group them together anyway.
166 We may not immediately return from the recursive call here, lest
167 all_constant gets lost. */
169 if (CONSTANT_P (XEXP (x, 1)))
171 rtx term = plus_constant (mode, XEXP (x, 1), c, inplace);
172 if (term == const0_rtx)
173 x = XEXP (x, 0);
174 else if (inplace)
175 XEXP (x, 1) = term;
176 else
177 x = gen_rtx_PLUS (mode, XEXP (x, 0), term);
178 c = 0;
180 else if (rtx *const_loc = find_constant_term_loc (&y))
182 if (!inplace)
184 /* We need to be careful since X may be shared and we can't
185 modify it in place. */
186 x = copy_rtx (x);
187 const_loc = find_constant_term_loc (&x);
189 *const_loc = plus_constant (mode, *const_loc, c, true);
190 c = 0;
192 break;
194 default:
195 if (CONST_POLY_INT_P (x))
196 return immed_wide_int_const (const_poly_int_value (x) + c, mode);
197 break;
200 if (maybe_ne (c, 0))
201 x = gen_rtx_PLUS (mode, x, gen_int_mode (c, mode));
203 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
204 return x;
205 else if (all_constant)
206 return gen_rtx_CONST (mode, x);
207 else
208 return x;
211 /* If X is a sum, return a new sum like X but lacking any constant terms.
212 Add all the removed constant terms into *CONSTPTR.
213 X itself is not altered. The result != X if and only if
214 it is not isomorphic to X. */
217 eliminate_constant_term (rtx x, rtx *constptr)
219 rtx x0, x1;
220 rtx tem;
222 if (GET_CODE (x) != PLUS)
223 return x;
225 /* First handle constants appearing at this level explicitly. */
226 if (CONST_INT_P (XEXP (x, 1))
227 && (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
228 XEXP (x, 1))) != 0
229 && CONST_INT_P (tem))
231 *constptr = tem;
232 return eliminate_constant_term (XEXP (x, 0), constptr);
235 tem = const0_rtx;
236 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
237 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
238 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
239 && (tem = simplify_binary_operation (PLUS, GET_MODE (x),
240 *constptr, tem)) != 0
241 && CONST_INT_P (tem))
243 *constptr = tem;
244 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
247 return x;
251 /* Return a copy of X in which all memory references
252 and all constants that involve symbol refs
253 have been replaced with new temporary registers.
254 Also emit code to load the memory locations and constants
255 into those registers.
257 If X contains no such constants or memory references,
258 X itself (not a copy) is returned.
260 If a constant is found in the address that is not a legitimate constant
261 in an insn, it is left alone in the hope that it might be valid in the
262 address.
264 X may contain no arithmetic except addition, subtraction and multiplication.
265 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
267 static rtx
268 break_out_memory_refs (rtx x)
270 if (MEM_P (x)
271 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
272 && GET_MODE (x) != VOIDmode))
273 x = force_reg (GET_MODE (x), x);
274 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
275 || GET_CODE (x) == MULT)
277 rtx op0 = break_out_memory_refs (XEXP (x, 0));
278 rtx op1 = break_out_memory_refs (XEXP (x, 1));
280 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
281 x = simplify_gen_binary (GET_CODE (x), GET_MODE (x), op0, op1);
284 return x;
287 /* Given X, a memory address in address space AS' pointer mode, convert it to
288 an address in the address space's address mode, or vice versa (TO_MODE says
289 which way). We take advantage of the fact that pointers are not allowed to
290 overflow by commuting arithmetic operations over conversions so that address
291 arithmetic insns can be used. IN_CONST is true if this conversion is inside
292 a CONST. NO_EMIT is true if no insns should be emitted, and instead
293 it should return NULL if it can't be simplified without emitting insns. */
296 convert_memory_address_addr_space_1 (scalar_int_mode to_mode ATTRIBUTE_UNUSED,
297 rtx x, addr_space_t as ATTRIBUTE_UNUSED,
298 bool in_const ATTRIBUTE_UNUSED,
299 bool no_emit ATTRIBUTE_UNUSED)
301 #ifndef POINTERS_EXTEND_UNSIGNED
302 gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode);
303 return x;
304 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
305 scalar_int_mode pointer_mode, address_mode, from_mode;
306 rtx temp;
307 enum rtx_code code;
309 /* If X already has the right mode, just return it. */
310 if (GET_MODE (x) == to_mode)
311 return x;
313 pointer_mode = targetm.addr_space.pointer_mode (as);
314 address_mode = targetm.addr_space.address_mode (as);
315 from_mode = to_mode == pointer_mode ? address_mode : pointer_mode;
317 /* Here we handle some special cases. If none of them apply, fall through
318 to the default case. */
319 switch (GET_CODE (x))
321 CASE_CONST_SCALAR_INT:
322 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
323 code = TRUNCATE;
324 else if (POINTERS_EXTEND_UNSIGNED < 0)
325 break;
326 else if (POINTERS_EXTEND_UNSIGNED > 0)
327 code = ZERO_EXTEND;
328 else
329 code = SIGN_EXTEND;
330 temp = simplify_unary_operation (code, to_mode, x, from_mode);
331 if (temp)
332 return temp;
333 break;
335 case SUBREG:
336 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
337 && GET_MODE (SUBREG_REG (x)) == to_mode)
338 return SUBREG_REG (x);
339 break;
341 case LABEL_REF:
342 temp = gen_rtx_LABEL_REF (to_mode, label_ref_label (x));
343 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
344 return temp;
346 case SYMBOL_REF:
347 temp = shallow_copy_rtx (x);
348 PUT_MODE (temp, to_mode);
349 return temp;
351 case CONST:
353 auto *last = no_emit ? nullptr : get_last_insn ();
354 temp = convert_memory_address_addr_space_1 (to_mode, XEXP (x, 0), as,
355 true, no_emit);
356 if (temp && (no_emit || last == get_last_insn ()))
357 return gen_rtx_CONST (to_mode, temp);
358 return temp;
361 case PLUS:
362 case MULT:
363 /* For addition we can safely permute the conversion and addition
364 operation if one operand is a constant and converting the constant
365 does not change it or if one operand is a constant and we are
366 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
367 We can always safely permute them if we are making the address
368 narrower. Inside a CONST RTL, this is safe for both pointers
369 zero or sign extended as pointers cannot wrap. */
370 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
371 || (GET_CODE (x) == PLUS
372 && CONST_INT_P (XEXP (x, 1))
373 && ((in_const && POINTERS_EXTEND_UNSIGNED != 0)
374 || XEXP (x, 1) == convert_memory_address_addr_space_1
375 (to_mode, XEXP (x, 1), as, in_const,
376 no_emit)
377 || POINTERS_EXTEND_UNSIGNED < 0)))
379 temp = convert_memory_address_addr_space_1 (to_mode, XEXP (x, 0),
380 as, in_const, no_emit);
381 return (temp ? gen_rtx_fmt_ee (GET_CODE (x), to_mode,
382 temp, XEXP (x, 1))
383 : temp);
385 break;
387 case UNSPEC:
388 /* Assume that all UNSPECs in a constant address can be converted
389 operand-by-operand. We could add a target hook if some targets
390 require different behavior. */
391 if (in_const && GET_MODE (x) == from_mode)
393 unsigned int n = XVECLEN (x, 0);
394 rtvec v = gen_rtvec (n);
395 for (unsigned int i = 0; i < n; ++i)
397 rtx op = XVECEXP (x, 0, i);
398 if (GET_MODE (op) == from_mode)
399 op = convert_memory_address_addr_space_1 (to_mode, op, as,
400 in_const, no_emit);
401 RTVEC_ELT (v, i) = op;
403 return gen_rtx_UNSPEC (to_mode, v, XINT (x, 1));
405 break;
407 default:
408 break;
411 if (no_emit)
412 return NULL_RTX;
414 return convert_modes (to_mode, from_mode,
415 x, POINTERS_EXTEND_UNSIGNED);
416 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
419 /* Given X, a memory address in address space AS' pointer mode, convert it to
420 an address in the address space's address mode, or vice versa (TO_MODE says
421 which way). We take advantage of the fact that pointers are not allowed to
422 overflow by commuting arithmetic operations over conversions so that address
423 arithmetic insns can be used. */
426 convert_memory_address_addr_space (scalar_int_mode to_mode, rtx x,
427 addr_space_t as)
429 return convert_memory_address_addr_space_1 (to_mode, x, as, false, false);
433 /* Return something equivalent to X but valid as a memory address for something
434 of mode MODE in the named address space AS. When X is not itself valid,
435 this works by copying X or subexpressions of it into registers. */
438 memory_address_addr_space (machine_mode mode, rtx x, addr_space_t as)
440 rtx oldx = x;
441 scalar_int_mode address_mode = targetm.addr_space.address_mode (as);
443 x = convert_memory_address_addr_space (address_mode, x, as);
445 /* By passing constant addresses through registers
446 we get a chance to cse them. */
447 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
448 x = force_reg (address_mode, x);
450 /* We get better cse by rejecting indirect addressing at this stage.
451 Let the combiner create indirect addresses where appropriate.
452 For now, generate the code so that the subexpressions useful to share
453 are visible. But not if cse won't be done! */
454 else
456 if (! cse_not_expected && !REG_P (x))
457 x = break_out_memory_refs (x);
459 /* At this point, any valid address is accepted. */
460 if (memory_address_addr_space_p (mode, x, as))
461 goto done;
463 /* If it was valid before but breaking out memory refs invalidated it,
464 use it the old way. */
465 if (memory_address_addr_space_p (mode, oldx, as))
467 x = oldx;
468 goto done;
471 /* Perform machine-dependent transformations on X
472 in certain cases. This is not necessary since the code
473 below can handle all possible cases, but machine-dependent
474 transformations can make better code. */
476 rtx orig_x = x;
477 x = targetm.addr_space.legitimize_address (x, oldx, mode, as);
478 if (orig_x != x && memory_address_addr_space_p (mode, x, as))
479 goto done;
482 /* PLUS and MULT can appear in special ways
483 as the result of attempts to make an address usable for indexing.
484 Usually they are dealt with by calling force_operand, below.
485 But a sum containing constant terms is special
486 if removing them makes the sum a valid address:
487 then we generate that address in a register
488 and index off of it. We do this because it often makes
489 shorter code, and because the addresses thus generated
490 in registers often become common subexpressions. */
491 if (GET_CODE (x) == PLUS)
493 rtx constant_term = const0_rtx;
494 rtx y = eliminate_constant_term (x, &constant_term);
495 if (constant_term == const0_rtx
496 || ! memory_address_addr_space_p (mode, y, as))
497 x = force_operand (x, NULL_RTX);
498 else
500 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
501 if (! memory_address_addr_space_p (mode, y, as))
502 x = force_operand (x, NULL_RTX);
503 else
504 x = y;
508 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
509 x = force_operand (x, NULL_RTX);
511 /* If we have a register that's an invalid address,
512 it must be a hard reg of the wrong class. Copy it to a pseudo. */
513 else if (REG_P (x))
514 x = copy_to_reg (x);
516 /* Last resort: copy the value to a register, since
517 the register is a valid address. */
518 else
519 x = force_reg (address_mode, x);
522 done:
524 gcc_assert (memory_address_addr_space_p (mode, x, as));
525 /* If we didn't change the address, we are done. Otherwise, mark
526 a reg as a pointer if we have REG or REG + CONST_INT. */
527 if (oldx == x)
528 return x;
529 else if (REG_P (x))
530 mark_reg_pointer (x, BITS_PER_UNIT);
531 else if (GET_CODE (x) == PLUS
532 && REG_P (XEXP (x, 0))
533 && CONST_INT_P (XEXP (x, 1)))
534 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
536 /* OLDX may have been the address on a temporary. Update the address
537 to indicate that X is now used. */
538 update_temp_slot_address (oldx, x);
540 return x;
543 /* Convert a mem ref into one with a valid memory address.
544 Pass through anything else unchanged. */
547 validize_mem (rtx ref)
549 if (!MEM_P (ref))
550 return ref;
551 ref = use_anchored_address (ref);
552 if (memory_address_addr_space_p (GET_MODE (ref), XEXP (ref, 0),
553 MEM_ADDR_SPACE (ref)))
554 return ref;
556 /* Don't alter REF itself, since that is probably a stack slot. */
557 return replace_equiv_address (ref, XEXP (ref, 0));
560 /* If X is a memory reference to a member of an object block, try rewriting
561 it to use an anchor instead. Return the new memory reference on success
562 and the old one on failure. */
565 use_anchored_address (rtx x)
567 rtx base;
568 HOST_WIDE_INT offset;
569 machine_mode mode;
571 if (!flag_section_anchors)
572 return x;
574 if (!MEM_P (x))
575 return x;
577 /* Split the address into a base and offset. */
578 base = XEXP (x, 0);
579 offset = 0;
580 if (GET_CODE (base) == CONST
581 && GET_CODE (XEXP (base, 0)) == PLUS
582 && CONST_INT_P (XEXP (XEXP (base, 0), 1)))
584 offset += INTVAL (XEXP (XEXP (base, 0), 1));
585 base = XEXP (XEXP (base, 0), 0);
588 /* Check whether BASE is suitable for anchors. */
589 if (GET_CODE (base) != SYMBOL_REF
590 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base)
591 || SYMBOL_REF_ANCHOR_P (base)
592 || SYMBOL_REF_BLOCK (base) == NULL
593 || !targetm.use_anchors_for_symbol_p (base))
594 return x;
596 /* Decide where BASE is going to be. */
597 place_block_symbol (base);
599 /* Get the anchor we need to use. */
600 offset += SYMBOL_REF_BLOCK_OFFSET (base);
601 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset,
602 SYMBOL_REF_TLS_MODEL (base));
604 /* Work out the offset from the anchor. */
605 offset -= SYMBOL_REF_BLOCK_OFFSET (base);
607 /* If we're going to run a CSE pass, force the anchor into a register.
608 We will then be able to reuse registers for several accesses, if the
609 target costs say that that's worthwhile. */
610 mode = GET_MODE (base);
611 if (!cse_not_expected)
612 base = force_reg (mode, base);
614 return replace_equiv_address (x, plus_constant (mode, base, offset));
617 /* Copy the value or contents of X to a new temp reg and return that reg. */
620 copy_to_reg (rtx x)
622 rtx temp = gen_reg_rtx (GET_MODE (x));
624 /* If not an operand, must be an address with PLUS and MULT so
625 do the computation. */
626 if (! general_operand (x, VOIDmode))
627 x = force_operand (x, temp);
629 if (x != temp)
630 emit_move_insn (temp, x);
632 return temp;
635 /* Like copy_to_reg but always give the new register mode Pmode
636 in case X is a constant. */
639 copy_addr_to_reg (rtx x)
641 return copy_to_mode_reg (Pmode, x);
644 /* Like copy_to_reg but always give the new register mode MODE
645 in case X is a constant. */
648 copy_to_mode_reg (machine_mode mode, rtx x)
650 rtx temp = gen_reg_rtx (mode);
652 /* If not an operand, must be an address with PLUS and MULT so
653 do the computation. */
654 if (! general_operand (x, VOIDmode))
655 x = force_operand (x, temp);
657 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
658 if (x != temp)
659 emit_move_insn (temp, x);
660 return temp;
663 /* Load X into a register if it is not already one.
664 Use mode MODE for the register.
665 X should be valid for mode MODE, but it may be a constant which
666 is valid for all integer modes; that's why caller must specify MODE.
668 The caller must not alter the value in the register we return,
669 since we mark it as a "constant" register. */
672 force_reg (machine_mode mode, rtx x)
674 rtx temp, set;
675 rtx_insn *insn;
677 if (REG_P (x))
678 return x;
680 if (general_operand (x, mode))
682 temp = gen_reg_rtx (mode);
683 insn = emit_move_insn (temp, x);
685 else
687 temp = force_operand (x, NULL_RTX);
688 if (REG_P (temp))
689 insn = get_last_insn ();
690 else
692 rtx temp2 = gen_reg_rtx (mode);
693 insn = emit_move_insn (temp2, temp);
694 temp = temp2;
698 /* Let optimizers know that TEMP's value never changes
699 and that X can be substituted for it. Don't get confused
700 if INSN set something else (such as a SUBREG of TEMP). */
701 if (CONSTANT_P (x)
702 && (set = single_set (insn)) != 0
703 && SET_DEST (set) == temp
704 && ! rtx_equal_p (x, SET_SRC (set)))
705 set_unique_reg_note (insn, REG_EQUAL, x);
707 /* Let optimizers know that TEMP is a pointer, and if so, the
708 known alignment of that pointer. */
710 unsigned align = 0;
711 if (GET_CODE (x) == SYMBOL_REF)
713 align = BITS_PER_UNIT;
714 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
715 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
717 else if (GET_CODE (x) == LABEL_REF)
718 align = BITS_PER_UNIT;
719 else if (GET_CODE (x) == CONST
720 && GET_CODE (XEXP (x, 0)) == PLUS
721 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
722 && CONST_INT_P (XEXP (XEXP (x, 0), 1)))
724 rtx s = XEXP (XEXP (x, 0), 0);
725 rtx c = XEXP (XEXP (x, 0), 1);
726 unsigned sa, ca;
728 sa = BITS_PER_UNIT;
729 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
730 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
732 if (INTVAL (c) == 0)
733 align = sa;
734 else
736 ca = ctz_hwi (INTVAL (c)) * BITS_PER_UNIT;
737 align = MIN (sa, ca);
741 if (align || (MEM_P (x) && MEM_POINTER (x)))
742 mark_reg_pointer (temp, align);
745 return temp;
748 /* If X is a memory ref, copy its contents to a new temp reg and return
749 that reg. Otherwise, return X. */
752 force_not_mem (rtx x)
754 rtx temp;
756 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
757 return x;
759 temp = gen_reg_rtx (GET_MODE (x));
761 if (MEM_POINTER (x))
762 REG_POINTER (temp) = 1;
764 emit_move_insn (temp, x);
765 return temp;
768 /* Copy X to TARGET (if it's nonzero and a reg)
769 or to a new temp reg and return that reg.
770 MODE is the mode to use for X in case it is a constant. */
773 copy_to_suggested_reg (rtx x, rtx target, machine_mode mode)
775 rtx temp;
777 if (target && REG_P (target))
778 temp = target;
779 else
780 temp = gen_reg_rtx (mode);
782 emit_move_insn (temp, x);
783 return temp;
786 /* Return the mode to use to pass or return a scalar of TYPE and MODE.
787 PUNSIGNEDP points to the signedness of the type and may be adjusted
788 to show what signedness to use on extension operations.
790 FOR_RETURN is nonzero if the caller is promoting the return value
791 of FNDECL, else it is for promoting args. */
793 machine_mode
794 promote_function_mode (const_tree type, machine_mode mode, int *punsignedp,
795 const_tree funtype, int for_return)
797 /* Called without a type node for a libcall. */
798 if (type == NULL_TREE)
800 if (INTEGRAL_MODE_P (mode))
801 return targetm.calls.promote_function_mode (NULL_TREE, mode,
802 punsignedp, funtype,
803 for_return);
804 else
805 return mode;
808 switch (TREE_CODE (type))
810 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
811 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
812 case POINTER_TYPE: case REFERENCE_TYPE:
813 return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype,
814 for_return);
816 default:
817 return mode;
820 /* Return the mode to use to store a scalar of TYPE and MODE.
821 PUNSIGNEDP points to the signedness of the type and may be adjusted
822 to show what signedness to use on extension operations. */
824 machine_mode
825 promote_mode (const_tree type ATTRIBUTE_UNUSED, machine_mode mode,
826 int *punsignedp ATTRIBUTE_UNUSED)
828 #ifdef PROMOTE_MODE
829 enum tree_code code;
830 int unsignedp;
831 scalar_mode smode;
832 #endif
834 /* For libcalls this is invoked without TYPE from the backends
835 TARGET_PROMOTE_FUNCTION_MODE hooks. Don't do anything in that
836 case. */
837 if (type == NULL_TREE)
838 return mode;
840 /* FIXME: this is the same logic that was there until GCC 4.4, but we
841 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
842 is not defined. The affected targets are M32C, S390, SPARC. */
843 #ifdef PROMOTE_MODE
844 code = TREE_CODE (type);
845 unsignedp = *punsignedp;
847 switch (code)
849 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
850 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
851 /* Values of these types always have scalar mode. */
852 smode = as_a <scalar_mode> (mode);
853 PROMOTE_MODE (smode, unsignedp, type);
854 *punsignedp = unsignedp;
855 return smode;
857 #ifdef POINTERS_EXTEND_UNSIGNED
858 case REFERENCE_TYPE:
859 case POINTER_TYPE:
860 *punsignedp = POINTERS_EXTEND_UNSIGNED;
861 return targetm.addr_space.address_mode
862 (TYPE_ADDR_SPACE (TREE_TYPE (type)));
863 #endif
865 default:
866 return mode;
868 #else
869 return mode;
870 #endif
874 /* Use one of promote_mode or promote_function_mode to find the promoted
875 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
876 of DECL after promotion. */
878 machine_mode
879 promote_decl_mode (const_tree decl, int *punsignedp)
881 tree type = TREE_TYPE (decl);
882 int unsignedp = TYPE_UNSIGNED (type);
883 machine_mode mode = DECL_MODE (decl);
884 machine_mode pmode;
886 if (TREE_CODE (decl) == RESULT_DECL && !DECL_BY_REFERENCE (decl))
887 pmode = promote_function_mode (type, mode, &unsignedp,
888 TREE_TYPE (current_function_decl), 1);
889 else if (TREE_CODE (decl) == RESULT_DECL || TREE_CODE (decl) == PARM_DECL)
890 pmode = promote_function_mode (type, mode, &unsignedp,
891 TREE_TYPE (current_function_decl), 2);
892 else
893 pmode = promote_mode (type, mode, &unsignedp);
895 if (punsignedp)
896 *punsignedp = unsignedp;
897 return pmode;
900 /* Return the promoted mode for name. If it is a named SSA_NAME, it
901 is the same as promote_decl_mode. Otherwise, it is the promoted
902 mode of a temp decl of same type as the SSA_NAME, if we had created
903 one. */
905 machine_mode
906 promote_ssa_mode (const_tree name, int *punsignedp)
908 gcc_assert (TREE_CODE (name) == SSA_NAME);
910 /* Partitions holding parms and results must be promoted as expected
911 by function.cc. */
912 if (SSA_NAME_VAR (name)
913 && (TREE_CODE (SSA_NAME_VAR (name)) == PARM_DECL
914 || TREE_CODE (SSA_NAME_VAR (name)) == RESULT_DECL))
916 machine_mode mode = promote_decl_mode (SSA_NAME_VAR (name), punsignedp);
917 if (mode != BLKmode)
918 return mode;
921 tree type = TREE_TYPE (name);
922 int unsignedp = TYPE_UNSIGNED (type);
923 machine_mode pmode = promote_mode (type, TYPE_MODE (type), &unsignedp);
924 if (punsignedp)
925 *punsignedp = unsignedp;
927 return pmode;
932 /* Controls the behavior of {anti_,}adjust_stack. */
933 static bool suppress_reg_args_size;
935 /* A helper for adjust_stack and anti_adjust_stack. */
937 static void
938 adjust_stack_1 (rtx adjust, bool anti_p)
940 rtx temp;
941 rtx_insn *insn;
943 /* Hereafter anti_p means subtract_p. */
944 if (!STACK_GROWS_DOWNWARD)
945 anti_p = !anti_p;
947 temp = expand_binop (Pmode,
948 anti_p ? sub_optab : add_optab,
949 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
950 OPTAB_LIB_WIDEN);
952 if (temp != stack_pointer_rtx)
953 insn = emit_move_insn (stack_pointer_rtx, temp);
954 else
956 insn = get_last_insn ();
957 temp = single_set (insn);
958 gcc_assert (temp != NULL && SET_DEST (temp) == stack_pointer_rtx);
961 if (!suppress_reg_args_size)
962 add_args_size_note (insn, stack_pointer_delta);
965 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
966 This pops when ADJUST is positive. ADJUST need not be constant. */
968 void
969 adjust_stack (rtx adjust)
971 if (adjust == const0_rtx)
972 return;
974 /* We expect all variable sized adjustments to be multiple of
975 PREFERRED_STACK_BOUNDARY. */
976 poly_int64 const_adjust;
977 if (poly_int_rtx_p (adjust, &const_adjust))
978 stack_pointer_delta -= const_adjust;
980 adjust_stack_1 (adjust, false);
983 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
984 This pushes when ADJUST is positive. ADJUST need not be constant. */
986 void
987 anti_adjust_stack (rtx adjust)
989 if (adjust == const0_rtx)
990 return;
992 /* We expect all variable sized adjustments to be multiple of
993 PREFERRED_STACK_BOUNDARY. */
994 poly_int64 const_adjust;
995 if (poly_int_rtx_p (adjust, &const_adjust))
996 stack_pointer_delta += const_adjust;
998 adjust_stack_1 (adjust, true);
1001 /* Round the size of a block to be pushed up to the boundary required
1002 by this machine. SIZE is the desired size, which need not be constant. */
1004 static rtx
1005 round_push (rtx size)
1007 rtx align_rtx, alignm1_rtx;
1009 if (!SUPPORTS_STACK_ALIGNMENT
1010 || crtl->preferred_stack_boundary == MAX_SUPPORTED_STACK_ALIGNMENT)
1012 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
1014 if (align == 1)
1015 return size;
1017 if (CONST_INT_P (size))
1019 HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
1021 if (INTVAL (size) != new_size)
1022 size = GEN_INT (new_size);
1023 return size;
1026 align_rtx = GEN_INT (align);
1027 alignm1_rtx = GEN_INT (align - 1);
1029 else
1031 /* If crtl->preferred_stack_boundary might still grow, use
1032 virtual_preferred_stack_boundary_rtx instead. This will be
1033 substituted by the right value in vregs pass and optimized
1034 during combine. */
1035 align_rtx = virtual_preferred_stack_boundary_rtx;
1036 alignm1_rtx = force_operand (plus_constant (Pmode, align_rtx, -1),
1037 NULL_RTX);
1040 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1041 but we know it can't. So add ourselves and then do
1042 TRUNC_DIV_EXPR. */
1043 size = expand_binop (Pmode, add_optab, size, alignm1_rtx,
1044 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1045 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, align_rtx,
1046 NULL_RTX, 1);
1047 size = expand_mult (Pmode, size, align_rtx, NULL_RTX, 1);
1049 return size;
1052 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
1053 to a previously-created save area. If no save area has been allocated,
1054 this function will allocate one. If a save area is specified, it
1055 must be of the proper mode. */
1057 void
1058 emit_stack_save (enum save_level save_level, rtx *psave)
1060 rtx sa = *psave;
1061 /* The default is that we use a move insn and save in a Pmode object. */
1062 rtx_insn *(*fcn) (rtx, rtx) = gen_move_insn;
1063 machine_mode mode = STACK_SAVEAREA_MODE (save_level);
1065 /* See if this machine has anything special to do for this kind of save. */
1066 switch (save_level)
1068 case SAVE_BLOCK:
1069 if (targetm.have_save_stack_block ())
1070 fcn = targetm.gen_save_stack_block;
1071 break;
1072 case SAVE_FUNCTION:
1073 if (targetm.have_save_stack_function ())
1074 fcn = targetm.gen_save_stack_function;
1075 break;
1076 case SAVE_NONLOCAL:
1077 if (targetm.have_save_stack_nonlocal ())
1078 fcn = targetm.gen_save_stack_nonlocal;
1079 break;
1080 default:
1081 break;
1084 /* If there is no save area and we have to allocate one, do so. Otherwise
1085 verify the save area is the proper mode. */
1087 if (sa == 0)
1089 if (mode != VOIDmode)
1091 if (save_level == SAVE_NONLOCAL)
1092 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
1093 else
1094 *psave = sa = gen_reg_rtx (mode);
1098 do_pending_stack_adjust ();
1099 if (sa != 0)
1100 sa = validize_mem (sa);
1101 emit_insn (fcn (sa, stack_pointer_rtx));
1104 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1105 area made by emit_stack_save. If it is zero, we have nothing to do. */
1107 void
1108 emit_stack_restore (enum save_level save_level, rtx sa)
1110 /* The default is that we use a move insn. */
1111 rtx_insn *(*fcn) (rtx, rtx) = gen_move_insn;
1113 /* If stack_realign_drap, the x86 backend emits a prologue that aligns both
1114 STACK_POINTER and HARD_FRAME_POINTER.
1115 If stack_realign_fp, the x86 backend emits a prologue that aligns only
1116 STACK_POINTER. This renders the HARD_FRAME_POINTER unusable for accessing
1117 aligned variables, which is reflected in ix86_can_eliminate.
1118 We normally still have the realigned STACK_POINTER that we can use.
1119 But if there is a stack restore still present at reload, it can trigger
1120 mark_not_eliminable for the STACK_POINTER, leaving no way to eliminate
1121 FRAME_POINTER into a hard reg.
1122 To prevent this situation, we force need_drap if we emit a stack
1123 restore. */
1124 if (SUPPORTS_STACK_ALIGNMENT)
1125 crtl->need_drap = true;
1127 /* See if this machine has anything special to do for this kind of save. */
1128 switch (save_level)
1130 case SAVE_BLOCK:
1131 if (targetm.have_restore_stack_block ())
1132 fcn = targetm.gen_restore_stack_block;
1133 break;
1134 case SAVE_FUNCTION:
1135 if (targetm.have_restore_stack_function ())
1136 fcn = targetm.gen_restore_stack_function;
1137 break;
1138 case SAVE_NONLOCAL:
1139 if (targetm.have_restore_stack_nonlocal ())
1140 fcn = targetm.gen_restore_stack_nonlocal;
1141 break;
1142 default:
1143 break;
1146 if (sa != 0)
1148 sa = validize_mem (sa);
1149 /* These clobbers prevent the scheduler from moving
1150 references to variable arrays below the code
1151 that deletes (pops) the arrays. */
1152 emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
1153 emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx));
1156 discard_pending_stack_adjust ();
1158 emit_insn (fcn (stack_pointer_rtx, sa));
1161 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1162 function. This should be called whenever we allocate or deallocate
1163 dynamic stack space. */
1165 void
1166 update_nonlocal_goto_save_area (void)
1168 tree t_save;
1169 rtx r_save;
1171 /* The nonlocal_goto_save_area object is an array of N pointers. The
1172 first one is used for the frame pointer save; the rest are sized by
1173 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1174 of the stack save area slots. */
1175 t_save = build4 (ARRAY_REF,
1176 TREE_TYPE (TREE_TYPE (cfun->nonlocal_goto_save_area)),
1177 cfun->nonlocal_goto_save_area,
1178 integer_one_node, NULL_TREE, NULL_TREE);
1179 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1181 emit_stack_save (SAVE_NONLOCAL, &r_save);
1184 /* Record a new stack level for the current function. This should be called
1185 whenever we allocate or deallocate dynamic stack space. */
1187 void
1188 record_new_stack_level (void)
1190 /* Record the new stack level for nonlocal gotos. */
1191 if (cfun->nonlocal_goto_save_area)
1192 update_nonlocal_goto_save_area ();
1194 /* Record the new stack level for SJLJ exceptions. */
1195 if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ)
1196 update_sjlj_context ();
1199 /* Return an rtx doing runtime alignment to REQUIRED_ALIGN on TARGET. */
1202 align_dynamic_address (rtx target, unsigned required_align)
1204 if (required_align == BITS_PER_UNIT)
1205 return target;
1207 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1208 but we know it can't. So add ourselves and then do
1209 TRUNC_DIV_EXPR. */
1210 target = expand_binop (Pmode, add_optab, target,
1211 gen_int_mode (required_align / BITS_PER_UNIT - 1,
1212 Pmode),
1213 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1214 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1215 gen_int_mode (required_align / BITS_PER_UNIT,
1216 Pmode),
1217 NULL_RTX, 1);
1218 target = expand_mult (Pmode, target,
1219 gen_int_mode (required_align / BITS_PER_UNIT,
1220 Pmode),
1221 NULL_RTX, 1);
1223 return target;
1226 /* Return an rtx through *PSIZE, representing the size of an area of memory to
1227 be dynamically pushed on the stack.
1229 *PSIZE is an rtx representing the size of the area.
1231 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1232 parameter may be zero. If so, a proper value will be extracted
1233 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1235 REQUIRED_ALIGN is the alignment (in bits) required for the region
1236 of memory.
1238 If PSTACK_USAGE_SIZE is not NULL it points to a value that is increased for
1239 the additional size returned. */
1240 void
1241 get_dynamic_stack_size (rtx *psize, unsigned size_align,
1242 unsigned required_align,
1243 HOST_WIDE_INT *pstack_usage_size)
1245 rtx size = *psize;
1247 /* Ensure the size is in the proper mode. */
1248 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1249 size = convert_to_mode (Pmode, size, 1);
1251 if (CONST_INT_P (size))
1253 unsigned HOST_WIDE_INT lsb;
1255 lsb = INTVAL (size);
1256 lsb &= -lsb;
1258 /* Watch out for overflow truncating to "unsigned". */
1259 if (lsb > UINT_MAX / BITS_PER_UNIT)
1260 size_align = 1u << (HOST_BITS_PER_INT - 1);
1261 else
1262 size_align = (unsigned)lsb * BITS_PER_UNIT;
1264 else if (size_align < BITS_PER_UNIT)
1265 size_align = BITS_PER_UNIT;
1267 /* We can't attempt to minimize alignment necessary, because we don't
1268 know the final value of preferred_stack_boundary yet while executing
1269 this code. */
1270 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
1271 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1273 /* We will need to ensure that the address we return is aligned to
1274 REQUIRED_ALIGN. At this point in the compilation, we don't always
1275 know the final value of the STACK_DYNAMIC_OFFSET used in function.cc
1276 (it might depend on the size of the outgoing parameter lists, for
1277 example), so we must preventively align the value. We leave space
1278 in SIZE for the hole that might result from the alignment operation. */
1280 unsigned known_align = REGNO_POINTER_ALIGN (VIRTUAL_STACK_DYNAMIC_REGNUM);
1281 if (known_align == 0)
1282 known_align = BITS_PER_UNIT;
1283 if (required_align > known_align)
1285 unsigned extra = (required_align - known_align) / BITS_PER_UNIT;
1286 size = plus_constant (Pmode, size, extra);
1287 size = force_operand (size, NULL_RTX);
1288 if (size_align > known_align)
1289 size_align = known_align;
1291 if (flag_stack_usage_info && pstack_usage_size)
1292 *pstack_usage_size += extra;
1295 /* Round the size to a multiple of the required stack alignment.
1296 Since the stack is presumed to be rounded before this allocation,
1297 this will maintain the required alignment.
1299 If the stack grows downward, we could save an insn by subtracting
1300 SIZE from the stack pointer and then aligning the stack pointer.
1301 The problem with this is that the stack pointer may be unaligned
1302 between the execution of the subtraction and alignment insns and
1303 some machines do not allow this. Even on those that do, some
1304 signal handlers malfunction if a signal should occur between those
1305 insns. Since this is an extremely rare event, we have no reliable
1306 way of knowing which systems have this problem. So we avoid even
1307 momentarily mis-aligning the stack. */
1308 if (size_align % MAX_SUPPORTED_STACK_ALIGNMENT != 0)
1310 size = round_push (size);
1312 if (flag_stack_usage_info && pstack_usage_size)
1314 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
1315 *pstack_usage_size =
1316 (*pstack_usage_size + align - 1) / align * align;
1320 *psize = size;
1323 /* Return the number of bytes to "protect" on the stack for -fstack-check.
1325 "protect" in the context of -fstack-check means how many bytes we need
1326 to always ensure are available on the stack; as a consequence, this is
1327 also how many bytes are first skipped when probing the stack.
1329 On some targets we want to reuse the -fstack-check prologue support
1330 to give a degree of protection against stack clashing style attacks.
1332 In that scenario we do not want to skip bytes before probing as that
1333 would render the stack clash protections useless.
1335 So we never use STACK_CHECK_PROTECT directly. Instead we indirectly
1336 use it through this helper, which allows to provide different values
1337 for -fstack-check and -fstack-clash-protection. */
1339 HOST_WIDE_INT
1340 get_stack_check_protect (void)
1342 if (flag_stack_clash_protection)
1343 return 0;
1345 return STACK_CHECK_PROTECT;
1348 /* Return an rtx representing the address of an area of memory dynamically
1349 pushed on the stack.
1351 Any required stack pointer alignment is preserved.
1353 SIZE is an rtx representing the size of the area.
1355 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1356 parameter may be zero. If so, a proper value will be extracted
1357 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1359 REQUIRED_ALIGN is the alignment (in bits) required for the region
1360 of memory.
1362 MAX_SIZE is an upper bound for SIZE, if SIZE is not constant, or -1 if
1363 no such upper bound is known.
1365 If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
1366 stack space allocated by the generated code cannot be added with itself
1367 in the course of the execution of the function. It is always safe to
1368 pass FALSE here and the following criterion is sufficient in order to
1369 pass TRUE: every path in the CFG that starts at the allocation point and
1370 loops to it executes the associated deallocation code. */
1373 allocate_dynamic_stack_space (rtx size, unsigned size_align,
1374 unsigned required_align,
1375 HOST_WIDE_INT max_size,
1376 bool cannot_accumulate)
1378 HOST_WIDE_INT stack_usage_size = -1;
1379 rtx_code_label *final_label;
1380 rtx final_target, target;
1381 rtx addr = (virtuals_instantiated
1382 ? plus_constant (Pmode, stack_pointer_rtx,
1383 get_stack_dynamic_offset ())
1384 : virtual_stack_dynamic_rtx);
1386 /* If we're asking for zero bytes, it doesn't matter what we point
1387 to since we can't dereference it. But return a reasonable
1388 address anyway. */
1389 if (size == const0_rtx)
1390 return addr;
1392 /* Otherwise, show we're calling alloca or equivalent. */
1393 cfun->calls_alloca = 1;
1395 /* If stack usage info is requested, look into the size we are passed.
1396 We need to do so this early to avoid the obfuscation that may be
1397 introduced later by the various alignment operations. */
1398 if (flag_stack_usage_info)
1400 if (CONST_INT_P (size))
1401 stack_usage_size = INTVAL (size);
1402 else if (REG_P (size))
1404 /* Look into the last emitted insn and see if we can deduce
1405 something for the register. */
1406 rtx_insn *insn;
1407 rtx set, note;
1408 insn = get_last_insn ();
1409 if ((set = single_set (insn)) && rtx_equal_p (SET_DEST (set), size))
1411 if (CONST_INT_P (SET_SRC (set)))
1412 stack_usage_size = INTVAL (SET_SRC (set));
1413 else if ((note = find_reg_equal_equiv_note (insn))
1414 && CONST_INT_P (XEXP (note, 0)))
1415 stack_usage_size = INTVAL (XEXP (note, 0));
1419 /* If the size is not constant, try the maximum size. */
1420 if (stack_usage_size < 0)
1421 stack_usage_size = max_size;
1423 /* If the size is still not constant, we can't say anything. */
1424 if (stack_usage_size < 0)
1426 current_function_has_unbounded_dynamic_stack_size = 1;
1427 stack_usage_size = 0;
1431 get_dynamic_stack_size (&size, size_align, required_align, &stack_usage_size);
1433 target = gen_reg_rtx (Pmode);
1435 /* The size is supposed to be fully adjusted at this point so record it
1436 if stack usage info is requested. */
1437 if (flag_stack_usage_info)
1439 current_function_dynamic_stack_size += stack_usage_size;
1441 /* ??? This is gross but the only safe stance in the absence
1442 of stack usage oriented flow analysis. */
1443 if (!cannot_accumulate)
1444 current_function_has_unbounded_dynamic_stack_size = 1;
1447 do_pending_stack_adjust ();
1449 final_label = NULL;
1450 final_target = NULL_RTX;
1452 /* If we are splitting the stack, we need to ask the backend whether
1453 there is enough room on the current stack. If there isn't, or if
1454 the backend doesn't know how to tell is, then we need to call a
1455 function to allocate memory in some other way. This memory will
1456 be released when we release the current stack segment. The
1457 effect is that stack allocation becomes less efficient, but at
1458 least it doesn't cause a stack overflow. */
1459 if (flag_split_stack)
1461 rtx_code_label *available_label;
1462 rtx ask, space, func;
1464 available_label = NULL;
1466 if (targetm.have_split_stack_space_check ())
1468 available_label = gen_label_rtx ();
1470 /* This instruction will branch to AVAILABLE_LABEL if there
1471 are SIZE bytes available on the stack. */
1472 emit_insn (targetm.gen_split_stack_space_check
1473 (size, available_label));
1476 /* The __morestack_allocate_stack_space function will allocate
1477 memory using malloc. If the alignment of the memory returned
1478 by malloc does not meet REQUIRED_ALIGN, we increase SIZE to
1479 make sure we allocate enough space. */
1480 if (MALLOC_ABI_ALIGNMENT >= required_align)
1481 ask = size;
1482 else
1483 ask = expand_binop (Pmode, add_optab, size,
1484 gen_int_mode (required_align / BITS_PER_UNIT - 1,
1485 Pmode),
1486 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1488 func = init_one_libfunc ("__morestack_allocate_stack_space");
1490 space = emit_library_call_value (func, target, LCT_NORMAL, Pmode,
1491 ask, Pmode);
1493 if (available_label == NULL_RTX)
1494 return space;
1496 final_target = gen_reg_rtx (Pmode);
1498 emit_move_insn (final_target, space);
1500 final_label = gen_label_rtx ();
1501 emit_jump (final_label);
1503 emit_label (available_label);
1506 /* We ought to be called always on the toplevel and stack ought to be aligned
1507 properly. */
1508 gcc_assert (multiple_p (stack_pointer_delta,
1509 PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT));
1511 /* If needed, check that we have the required amount of stack. Take into
1512 account what has already been checked. */
1513 if (STACK_CHECK_MOVING_SP)
1515 else if (flag_stack_check == GENERIC_STACK_CHECK)
1516 probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE,
1517 size);
1518 else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
1519 probe_stack_range (get_stack_check_protect (), size);
1521 /* Don't let anti_adjust_stack emit notes. */
1522 suppress_reg_args_size = true;
1524 /* Perform the required allocation from the stack. Some systems do
1525 this differently than simply incrementing/decrementing from the
1526 stack pointer, such as acquiring the space by calling malloc(). */
1527 if (targetm.have_allocate_stack ())
1529 class expand_operand ops[2];
1530 /* We don't have to check against the predicate for operand 0 since
1531 TARGET is known to be a pseudo of the proper mode, which must
1532 be valid for the operand. */
1533 create_fixed_operand (&ops[0], target);
1534 create_convert_operand_to (&ops[1], size, STACK_SIZE_MODE, true);
1535 expand_insn (targetm.code_for_allocate_stack, 2, ops);
1537 else
1539 poly_int64 saved_stack_pointer_delta;
1541 if (!STACK_GROWS_DOWNWARD)
1542 emit_move_insn (target, force_operand (addr, target));
1544 /* Check stack bounds if necessary. */
1545 if (crtl->limit_stack)
1547 rtx available;
1548 rtx_code_label *space_available = gen_label_rtx ();
1549 if (STACK_GROWS_DOWNWARD)
1550 available = expand_binop (Pmode, sub_optab,
1551 stack_pointer_rtx, stack_limit_rtx,
1552 NULL_RTX, 1, OPTAB_WIDEN);
1553 else
1554 available = expand_binop (Pmode, sub_optab,
1555 stack_limit_rtx, stack_pointer_rtx,
1556 NULL_RTX, 1, OPTAB_WIDEN);
1558 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1559 space_available);
1560 if (targetm.have_trap ())
1561 emit_insn (targetm.gen_trap ());
1562 else
1563 error ("stack limits not supported on this target");
1564 emit_barrier ();
1565 emit_label (space_available);
1568 saved_stack_pointer_delta = stack_pointer_delta;
1570 /* If stack checking or stack clash protection is requested,
1571 then probe the stack while allocating space from it. */
1572 if (flag_stack_check && STACK_CHECK_MOVING_SP)
1573 anti_adjust_stack_and_probe (size, false);
1574 else if (flag_stack_clash_protection)
1575 anti_adjust_stack_and_probe_stack_clash (size);
1576 else
1577 anti_adjust_stack (size);
1579 /* Even if size is constant, don't modify stack_pointer_delta.
1580 The constant size alloca should preserve
1581 crtl->preferred_stack_boundary alignment. */
1582 stack_pointer_delta = saved_stack_pointer_delta;
1584 if (STACK_GROWS_DOWNWARD)
1585 emit_move_insn (target, force_operand (addr, target));
1588 suppress_reg_args_size = false;
1590 /* Finish up the split stack handling. */
1591 if (final_label != NULL_RTX)
1593 gcc_assert (flag_split_stack);
1594 emit_move_insn (final_target, target);
1595 emit_label (final_label);
1596 target = final_target;
1599 target = align_dynamic_address (target, required_align);
1601 /* Now that we've committed to a return value, mark its alignment. */
1602 mark_reg_pointer (target, required_align);
1604 /* Record the new stack level. */
1605 record_new_stack_level ();
1607 return target;
1610 /* Return an rtx representing the address of an area of memory already
1611 statically pushed onto the stack in the virtual stack vars area. (It is
1612 assumed that the area is allocated in the function prologue.)
1614 Any required stack pointer alignment is preserved.
1616 OFFSET is the offset of the area into the virtual stack vars area.
1618 REQUIRED_ALIGN is the alignment (in bits) required for the region
1619 of memory.
1621 BASE is the rtx of the base of this virtual stack vars area.
1622 The only time this is not `virtual_stack_vars_rtx` is when tagging pointers
1623 on the stack. */
1626 get_dynamic_stack_base (poly_int64 offset, unsigned required_align, rtx base)
1628 rtx target;
1630 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
1631 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1633 target = gen_reg_rtx (Pmode);
1634 emit_move_insn (target, base);
1635 target = expand_binop (Pmode, add_optab, target,
1636 gen_int_mode (offset, Pmode),
1637 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1638 target = align_dynamic_address (target, required_align);
1640 /* Now that we've committed to a return value, mark its alignment. */
1641 mark_reg_pointer (target, required_align);
1643 return target;
1646 /* A front end may want to override GCC's stack checking by providing a
1647 run-time routine to call to check the stack, so provide a mechanism for
1648 calling that routine. */
1650 static GTY(()) rtx stack_check_libfunc;
1652 void
1653 set_stack_check_libfunc (const char *libfunc_name)
1655 gcc_assert (stack_check_libfunc == NULL_RTX);
1656 stack_check_libfunc = gen_rtx_SYMBOL_REF (Pmode, libfunc_name);
1657 tree ptype
1658 = Pmode == ptr_mode
1659 ? ptr_type_node
1660 : lang_hooks.types.type_for_mode (Pmode, 1);
1661 tree ftype
1662 = build_function_type_list (void_type_node, ptype, NULL_TREE);
1663 tree decl = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
1664 get_identifier (libfunc_name), ftype);
1665 DECL_EXTERNAL (decl) = 1;
1666 SET_SYMBOL_REF_DECL (stack_check_libfunc, decl);
1669 /* Emit one stack probe at ADDRESS, an address within the stack. */
1671 void
1672 emit_stack_probe (rtx address)
1674 if (targetm.have_probe_stack_address ())
1676 class expand_operand ops[1];
1677 insn_code icode = targetm.code_for_probe_stack_address;
1678 create_address_operand (ops, address);
1679 maybe_legitimize_operands (icode, 0, 1, ops);
1680 expand_insn (icode, 1, ops);
1682 else
1684 rtx memref = gen_rtx_MEM (word_mode, address);
1686 MEM_VOLATILE_P (memref) = 1;
1687 memref = validize_mem (memref);
1689 /* See if we have an insn to probe the stack. */
1690 if (targetm.have_probe_stack ())
1691 emit_insn (targetm.gen_probe_stack (memref));
1692 else
1693 emit_move_insn (memref, const0_rtx);
1697 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1698 FIRST is a constant and size is a Pmode RTX. These are offsets from
1699 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
1700 or subtract them from the stack pointer. */
1702 #define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
1704 #if STACK_GROWS_DOWNWARD
1705 #define STACK_GROW_OP MINUS
1706 #define STACK_GROW_OPTAB sub_optab
1707 #define STACK_GROW_OFF(off) -(off)
1708 #else
1709 #define STACK_GROW_OP PLUS
1710 #define STACK_GROW_OPTAB add_optab
1711 #define STACK_GROW_OFF(off) (off)
1712 #endif
1714 void
1715 probe_stack_range (HOST_WIDE_INT first, rtx size)
1717 /* First ensure SIZE is Pmode. */
1718 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1719 size = convert_to_mode (Pmode, size, 1);
1721 /* Next see if we have a function to check the stack. */
1722 if (stack_check_libfunc)
1724 rtx addr = memory_address (Pmode,
1725 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1726 stack_pointer_rtx,
1727 plus_constant (Pmode,
1728 size, first)));
1729 emit_library_call (stack_check_libfunc, LCT_THROW, VOIDmode,
1730 addr, Pmode);
1733 /* Next see if we have an insn to check the stack. */
1734 else if (targetm.have_check_stack ())
1736 class expand_operand ops[1];
1737 rtx addr = memory_address (Pmode,
1738 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1739 stack_pointer_rtx,
1740 plus_constant (Pmode,
1741 size, first)));
1742 bool success;
1743 create_input_operand (&ops[0], addr, Pmode);
1744 success = maybe_expand_insn (targetm.code_for_check_stack, 1, ops);
1745 gcc_assert (success);
1748 /* Otherwise we have to generate explicit probes. If we have a constant
1749 small number of them to generate, that's the easy case. */
1750 else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
1752 HOST_WIDE_INT isize = INTVAL (size), i;
1753 rtx addr;
1755 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
1756 it exceeds SIZE. If only one probe is needed, this will not
1757 generate any code. Then probe at FIRST + SIZE. */
1758 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
1760 addr = memory_address (Pmode,
1761 plus_constant (Pmode, stack_pointer_rtx,
1762 STACK_GROW_OFF (first + i)));
1763 emit_stack_probe (addr);
1766 addr = memory_address (Pmode,
1767 plus_constant (Pmode, stack_pointer_rtx,
1768 STACK_GROW_OFF (first + isize)));
1769 emit_stack_probe (addr);
1772 /* In the variable case, do the same as above, but in a loop. Note that we
1773 must be extra careful with variables wrapping around because we might be
1774 at the very top (or the very bottom) of the address space and we have to
1775 be able to handle this case properly; in particular, we use an equality
1776 test for the loop condition. */
1777 else
1779 rtx rounded_size, rounded_size_op, test_addr, last_addr, temp;
1780 rtx_code_label *loop_lab = gen_label_rtx ();
1781 rtx_code_label *end_lab = gen_label_rtx ();
1783 /* Step 1: round SIZE to the previous multiple of the interval. */
1785 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1786 rounded_size
1787 = simplify_gen_binary (AND, Pmode, size,
1788 gen_int_mode (-PROBE_INTERVAL, Pmode));
1789 rounded_size_op = force_operand (rounded_size, NULL_RTX);
1792 /* Step 2: compute initial and final value of the loop counter. */
1794 /* TEST_ADDR = SP + FIRST. */
1795 test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1796 stack_pointer_rtx,
1797 gen_int_mode (first, Pmode)),
1798 NULL_RTX);
1800 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
1801 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1802 test_addr,
1803 rounded_size_op), NULL_RTX);
1806 /* Step 3: the loop
1808 while (TEST_ADDR != LAST_ADDR)
1810 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
1811 probe at TEST_ADDR
1814 probes at FIRST + N * PROBE_INTERVAL for values of N from 1
1815 until it is equal to ROUNDED_SIZE. */
1817 emit_label (loop_lab);
1819 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
1820 emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1,
1821 end_lab);
1823 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
1824 temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr,
1825 gen_int_mode (PROBE_INTERVAL, Pmode), test_addr,
1826 1, OPTAB_WIDEN);
1828 /* There is no guarantee that expand_binop constructs its result
1829 in TEST_ADDR. So copy into TEST_ADDR if necessary. */
1830 if (temp != test_addr)
1831 emit_move_insn (test_addr, temp);
1833 /* Probe at TEST_ADDR. */
1834 emit_stack_probe (test_addr);
1836 emit_jump (loop_lab);
1838 emit_label (end_lab);
1841 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
1842 that SIZE is equal to ROUNDED_SIZE. */
1844 /* TEMP = SIZE - ROUNDED_SIZE. */
1845 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
1846 if (temp != const0_rtx)
1848 rtx addr;
1850 if (CONST_INT_P (temp))
1852 /* Use [base + disp} addressing mode if supported. */
1853 HOST_WIDE_INT offset = INTVAL (temp);
1854 addr = memory_address (Pmode,
1855 plus_constant (Pmode, last_addr,
1856 STACK_GROW_OFF (offset)));
1858 else
1860 /* Manual CSE if the difference is not known at compile-time. */
1861 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
1862 addr = memory_address (Pmode,
1863 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1864 last_addr, temp));
1867 emit_stack_probe (addr);
1871 /* Make sure nothing is scheduled before we are done. */
1872 emit_insn (gen_blockage ());
1875 /* Compute parameters for stack clash probing a dynamic stack
1876 allocation of SIZE bytes.
1878 We compute ROUNDED_SIZE, LAST_ADDR, RESIDUAL and PROBE_INTERVAL.
1880 Additionally we conditionally dump the type of probing that will
1881 be needed given the values computed. */
1883 void
1884 compute_stack_clash_protection_loop_data (rtx *rounded_size, rtx *last_addr,
1885 rtx *residual,
1886 HOST_WIDE_INT *probe_interval,
1887 rtx size)
1889 /* Round SIZE down to STACK_CLASH_PROTECTION_PROBE_INTERVAL */
1890 *probe_interval
1891 = 1 << param_stack_clash_protection_probe_interval;
1892 *rounded_size = simplify_gen_binary (AND, Pmode, size,
1893 GEN_INT (-*probe_interval));
1895 /* Compute the value of the stack pointer for the last iteration.
1896 It's just SP + ROUNDED_SIZE. */
1897 rtx rounded_size_op = force_operand (*rounded_size, NULL_RTX);
1898 *last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1899 stack_pointer_rtx,
1900 rounded_size_op),
1901 NULL_RTX);
1903 /* Compute any residuals not allocated by the loop above. Residuals
1904 are just the ROUNDED_SIZE - SIZE. */
1905 *residual = simplify_gen_binary (MINUS, Pmode, size, *rounded_size);
1907 /* Dump key information to make writing tests easy. */
1908 if (dump_file)
1910 if (*rounded_size == CONST0_RTX (Pmode))
1911 fprintf (dump_file,
1912 "Stack clash skipped dynamic allocation and probing loop.\n");
1913 else if (CONST_INT_P (*rounded_size)
1914 && INTVAL (*rounded_size) <= 4 * *probe_interval)
1915 fprintf (dump_file,
1916 "Stack clash dynamic allocation and probing inline.\n");
1917 else if (CONST_INT_P (*rounded_size))
1918 fprintf (dump_file,
1919 "Stack clash dynamic allocation and probing in "
1920 "rotated loop.\n");
1921 else
1922 fprintf (dump_file,
1923 "Stack clash dynamic allocation and probing in loop.\n");
1925 if (*residual != CONST0_RTX (Pmode))
1926 fprintf (dump_file,
1927 "Stack clash dynamic allocation and probing residuals.\n");
1928 else
1929 fprintf (dump_file,
1930 "Stack clash skipped dynamic allocation and "
1931 "probing residuals.\n");
1935 /* Emit the start of an allocate/probe loop for stack
1936 clash protection.
1938 LOOP_LAB and END_LAB are returned for use when we emit the
1939 end of the loop.
1941 LAST addr is the value for SP which stops the loop. */
1942 void
1943 emit_stack_clash_protection_probe_loop_start (rtx *loop_lab,
1944 rtx *end_lab,
1945 rtx last_addr,
1946 bool rotated)
1948 /* Essentially we want to emit any setup code, the top of loop
1949 label and the comparison at the top of the loop. */
1950 *loop_lab = gen_label_rtx ();
1951 *end_lab = gen_label_rtx ();
1953 emit_label (*loop_lab);
1954 if (!rotated)
1955 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
1956 Pmode, 1, *end_lab);
1959 /* Emit the end of a stack clash probing loop.
1961 This consists of just the jump back to LOOP_LAB and
1962 emitting END_LOOP after the loop. */
1964 void
1965 emit_stack_clash_protection_probe_loop_end (rtx loop_lab, rtx end_loop,
1966 rtx last_addr, bool rotated)
1968 if (rotated)
1969 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, NE, NULL_RTX,
1970 Pmode, 1, loop_lab);
1971 else
1972 emit_jump (loop_lab);
1974 emit_label (end_loop);
1978 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
1979 while probing it. This pushes when SIZE is positive. SIZE need not
1980 be constant.
1982 This is subtly different than anti_adjust_stack_and_probe to try and
1983 prevent stack-clash attacks
1985 1. It must assume no knowledge of the probing state, any allocation
1986 must probe.
1988 Consider the case of a 1 byte alloca in a loop. If the sum of the
1989 allocations is large, then this could be used to jump the guard if
1990 probes were not emitted.
1992 2. It never skips probes, whereas anti_adjust_stack_and_probe will
1993 skip the probe on the first PROBE_INTERVAL on the assumption it
1994 was already done in the prologue and in previous allocations.
1996 3. It only allocates and probes SIZE bytes, it does not need to
1997 allocate/probe beyond that because this probing style does not
1998 guarantee signal handling capability if the guard is hit. */
2000 void
2001 anti_adjust_stack_and_probe_stack_clash (rtx size)
2003 /* First ensure SIZE is Pmode. */
2004 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
2005 size = convert_to_mode (Pmode, size, 1);
2007 /* We can get here with a constant size on some targets. */
2008 rtx rounded_size, last_addr, residual;
2009 HOST_WIDE_INT probe_interval, probe_range;
2010 bool target_probe_range_p = false;
2011 compute_stack_clash_protection_loop_data (&rounded_size, &last_addr,
2012 &residual, &probe_interval, size);
2014 /* Get the back-end specific probe ranges. */
2015 probe_range = targetm.stack_clash_protection_alloca_probe_range ();
2016 target_probe_range_p = probe_range != 0;
2017 gcc_assert (probe_range >= 0);
2019 /* If no back-end specific range defined, default to the top of the newly
2020 allocated range. */
2021 if (probe_range == 0)
2022 probe_range = probe_interval - GET_MODE_SIZE (word_mode);
2024 if (rounded_size != CONST0_RTX (Pmode))
2026 if (CONST_INT_P (rounded_size)
2027 && INTVAL (rounded_size) <= 4 * probe_interval)
2029 for (HOST_WIDE_INT i = 0;
2030 i < INTVAL (rounded_size);
2031 i += probe_interval)
2033 anti_adjust_stack (GEN_INT (probe_interval));
2034 /* The prologue does not probe residuals. Thus the offset
2035 here to probe just beyond what the prologue had already
2036 allocated. */
2037 emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
2038 probe_range));
2040 emit_insn (gen_blockage ());
2043 else
2045 rtx loop_lab, end_loop;
2046 bool rotate_loop = CONST_INT_P (rounded_size);
2047 emit_stack_clash_protection_probe_loop_start (&loop_lab, &end_loop,
2048 last_addr, rotate_loop);
2050 anti_adjust_stack (GEN_INT (probe_interval));
2052 /* The prologue does not probe residuals. Thus the offset here
2053 to probe just beyond what the prologue had already
2054 allocated. */
2055 emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
2056 probe_range));
2058 emit_stack_clash_protection_probe_loop_end (loop_lab, end_loop,
2059 last_addr, rotate_loop);
2060 emit_insn (gen_blockage ());
2064 if (residual != CONST0_RTX (Pmode))
2066 rtx label = NULL_RTX;
2067 /* RESIDUAL could be zero at runtime and in that case *sp could
2068 hold live data. Furthermore, we do not want to probe into the
2069 red zone.
2071 If TARGET_PROBE_RANGE_P then the target has promised it's safe to
2072 probe at offset 0. In which case we no longer have to check for
2073 RESIDUAL == 0. However we still need to probe at the right offset
2074 when RESIDUAL > PROBE_RANGE, in which case we probe at PROBE_RANGE.
2076 If !TARGET_PROBE_RANGE_P then go ahead and just guard the probe at *sp
2077 on RESIDUAL != 0 at runtime if RESIDUAL is not a compile time constant.
2079 anti_adjust_stack (residual);
2081 if (!CONST_INT_P (residual))
2083 label = gen_label_rtx ();
2084 rtx_code op = target_probe_range_p ? LT : EQ;
2085 rtx probe_cmp_value = target_probe_range_p
2086 ? gen_rtx_CONST_INT (GET_MODE (residual), probe_range)
2087 : CONST0_RTX (GET_MODE (residual));
2089 if (target_probe_range_p)
2090 emit_stack_probe (stack_pointer_rtx);
2092 emit_cmp_and_jump_insns (residual, probe_cmp_value,
2093 op, NULL_RTX, Pmode, 1, label);
2096 rtx x = NULL_RTX;
2098 /* If RESIDUAL isn't a constant and TARGET_PROBE_RANGE_P then we probe up
2099 by the ABI defined safe value. */
2100 if (!CONST_INT_P (residual) && target_probe_range_p)
2101 x = GEN_INT (probe_range);
2102 /* If RESIDUAL is a constant but smaller than the ABI defined safe value,
2103 we still want to probe up, but the safest amount if a word. */
2104 else if (target_probe_range_p)
2106 if (INTVAL (residual) <= probe_range)
2107 x = GEN_INT (GET_MODE_SIZE (word_mode));
2108 else
2109 x = GEN_INT (probe_range);
2111 else
2112 /* If nothing else, probe at the top of the new allocation. */
2113 x = plus_constant (Pmode, residual, -GET_MODE_SIZE (word_mode));
2115 emit_stack_probe (gen_rtx_PLUS (Pmode, stack_pointer_rtx, x));
2117 emit_insn (gen_blockage ());
2118 if (!CONST_INT_P (residual))
2119 emit_label (label);
2124 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
2125 while probing it. This pushes when SIZE is positive. SIZE need not
2126 be constant. If ADJUST_BACK is true, adjust back the stack pointer
2127 by plus SIZE at the end. */
2129 void
2130 anti_adjust_stack_and_probe (rtx size, bool adjust_back)
2132 /* We skip the probe for the first interval + a small dope of 4 words and
2133 probe that many bytes past the specified size to maintain a protection
2134 area at the botton of the stack. */
2135 const int dope = 4 * UNITS_PER_WORD;
2137 /* First ensure SIZE is Pmode. */
2138 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
2139 size = convert_to_mode (Pmode, size, 1);
2141 /* If we have a constant small number of probes to generate, that's the
2142 easy case. */
2143 if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
2145 HOST_WIDE_INT isize = INTVAL (size), i;
2146 bool first_probe = true;
2148 /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
2149 values of N from 1 until it exceeds SIZE. If only one probe is
2150 needed, this will not generate any code. Then adjust and probe
2151 to PROBE_INTERVAL + SIZE. */
2152 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
2154 if (first_probe)
2156 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope));
2157 first_probe = false;
2159 else
2160 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
2161 emit_stack_probe (stack_pointer_rtx);
2164 if (first_probe)
2165 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
2166 else
2167 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL - i));
2168 emit_stack_probe (stack_pointer_rtx);
2171 /* In the variable case, do the same as above, but in a loop. Note that we
2172 must be extra careful with variables wrapping around because we might be
2173 at the very top (or the very bottom) of the address space and we have to
2174 be able to handle this case properly; in particular, we use an equality
2175 test for the loop condition. */
2176 else
2178 rtx rounded_size, rounded_size_op, last_addr, temp;
2179 rtx_code_label *loop_lab = gen_label_rtx ();
2180 rtx_code_label *end_lab = gen_label_rtx ();
2183 /* Step 1: round SIZE to the previous multiple of the interval. */
2185 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
2186 rounded_size
2187 = simplify_gen_binary (AND, Pmode, size,
2188 gen_int_mode (-PROBE_INTERVAL, Pmode));
2189 rounded_size_op = force_operand (rounded_size, NULL_RTX);
2192 /* Step 2: compute initial and final value of the loop counter. */
2194 /* SP = SP_0 + PROBE_INTERVAL. */
2195 anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
2197 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
2198 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
2199 stack_pointer_rtx,
2200 rounded_size_op), NULL_RTX);
2203 /* Step 3: the loop
2205 while (SP != LAST_ADDR)
2207 SP = SP + PROBE_INTERVAL
2208 probe at SP
2211 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
2212 values of N from 1 until it is equal to ROUNDED_SIZE. */
2214 emit_label (loop_lab);
2216 /* Jump to END_LAB if SP == LAST_ADDR. */
2217 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
2218 Pmode, 1, end_lab);
2220 /* SP = SP + PROBE_INTERVAL and probe at SP. */
2221 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
2222 emit_stack_probe (stack_pointer_rtx);
2224 emit_jump (loop_lab);
2226 emit_label (end_lab);
2229 /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
2230 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
2232 /* TEMP = SIZE - ROUNDED_SIZE. */
2233 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
2234 if (temp != const0_rtx)
2236 /* Manual CSE if the difference is not known at compile-time. */
2237 if (GET_CODE (temp) != CONST_INT)
2238 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
2239 anti_adjust_stack (temp);
2240 emit_stack_probe (stack_pointer_rtx);
2244 /* Adjust back and account for the additional first interval. */
2245 if (adjust_back)
2246 adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
2247 else
2248 adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
2251 /* Return an rtx representing the register or memory location
2252 in which a scalar value of data type VALTYPE
2253 was returned by a function call to function FUNC.
2254 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
2255 function is known, otherwise 0.
2256 OUTGOING is 1 if on a machine with register windows this function
2257 should return the register in which the function will put its result
2258 and 0 otherwise. */
2261 hard_function_value (const_tree valtype, const_tree func, const_tree fntype,
2262 int outgoing ATTRIBUTE_UNUSED)
2264 rtx val;
2266 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
2268 if (REG_P (val)
2269 && GET_MODE (val) == BLKmode)
2271 unsigned HOST_WIDE_INT bytes = arg_int_size_in_bytes (valtype);
2272 opt_scalar_int_mode tmpmode;
2274 /* int_size_in_bytes can return -1. We don't need a check here
2275 since the value of bytes will then be large enough that no
2276 mode will match anyway. */
2278 FOR_EACH_MODE_IN_CLASS (tmpmode, MODE_INT)
2280 /* Have we found a large enough mode? */
2281 if (GET_MODE_SIZE (tmpmode.require ()) >= bytes)
2282 break;
2285 PUT_MODE (val, tmpmode.require ());
2287 return val;
2290 /* Return an rtx representing the register or memory location
2291 in which a scalar value of mode MODE was returned by a library call. */
2294 hard_libcall_value (machine_mode mode, rtx fun)
2296 return targetm.calls.libcall_value (mode, fun);
2299 /* Look up the tree code for a given rtx code
2300 to provide the arithmetic operation for real_arithmetic.
2301 The function returns an int because the caller may not know
2302 what `enum tree_code' means. */
2305 rtx_to_tree_code (enum rtx_code code)
2307 enum tree_code tcode;
2309 switch (code)
2311 case PLUS:
2312 tcode = PLUS_EXPR;
2313 break;
2314 case MINUS:
2315 tcode = MINUS_EXPR;
2316 break;
2317 case MULT:
2318 tcode = MULT_EXPR;
2319 break;
2320 case DIV:
2321 tcode = RDIV_EXPR;
2322 break;
2323 case SMIN:
2324 tcode = MIN_EXPR;
2325 break;
2326 case SMAX:
2327 tcode = MAX_EXPR;
2328 break;
2329 default:
2330 tcode = LAST_AND_UNUSED_TREE_CODE;
2331 break;
2333 return ((int) tcode);
2336 #include "gt-explow.h"