PR c++/86728 - C variadic generic lambda.
[official-gcc.git] / gcc / explow.c
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1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987-2018 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 "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"
45 static rtx break_out_memory_refs (rtx);
46 static void anti_adjust_stack_and_probe_stack_clash (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)
60 || POINTER_BOUNDS_MODE_P (mode));
62 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
63 if (smode == BImode)
64 return c & 1 ? STORE_FLAG_VALUE : 0;
66 /* Sign-extend for the requested mode. */
68 if (width < HOST_BITS_PER_WIDE_INT)
70 HOST_WIDE_INT sign = 1;
71 sign <<= width - 1;
72 c &= (sign << 1) - 1;
73 c ^= sign;
74 c -= sign;
77 return c;
80 /* Likewise for polynomial values, using the sign-extended representation
81 for each individual coefficient. */
83 poly_int64
84 trunc_int_for_mode (poly_int64 x, machine_mode mode)
86 for (unsigned int i = 0; i < NUM_POLY_INT_COEFFS; ++i)
87 x.coeffs[i] = trunc_int_for_mode (x.coeffs[i], mode);
88 return x;
91 /* Return an rtx for the sum of X and the integer C, given that X has
92 mode MODE. INPLACE is true if X can be modified inplace or false
93 if it must be treated as immutable. */
95 rtx
96 plus_constant (machine_mode mode, rtx x, poly_int64 c, bool inplace)
98 RTX_CODE code;
99 rtx y;
100 rtx tem;
101 int all_constant = 0;
103 gcc_assert (GET_MODE (x) == VOIDmode || GET_MODE (x) == mode);
105 if (known_eq (c, 0))
106 return x;
108 restart:
110 code = GET_CODE (x);
111 y = x;
113 switch (code)
115 CASE_CONST_SCALAR_INT:
116 return immed_wide_int_const (wi::add (rtx_mode_t (x, mode), c), mode);
117 case MEM:
118 /* If this is a reference to the constant pool, try replacing it with
119 a reference to a new constant. If the resulting address isn't
120 valid, don't return it because we have no way to validize it. */
121 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
122 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
124 rtx cst = get_pool_constant (XEXP (x, 0));
126 if (GET_CODE (cst) == CONST_VECTOR
127 && GET_MODE_INNER (GET_MODE (cst)) == mode)
129 cst = gen_lowpart (mode, cst);
130 gcc_assert (cst);
132 if (GET_MODE (cst) == VOIDmode || GET_MODE (cst) == mode)
134 tem = plus_constant (mode, cst, c);
135 tem = force_const_mem (GET_MODE (x), tem);
136 /* Targets may disallow some constants in the constant pool, thus
137 force_const_mem may return NULL_RTX. */
138 if (tem && memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
139 return tem;
142 break;
144 case CONST:
145 /* If adding to something entirely constant, set a flag
146 so that we can add a CONST around the result. */
147 if (inplace && shared_const_p (x))
148 inplace = false;
149 x = XEXP (x, 0);
150 all_constant = 1;
151 goto restart;
153 case SYMBOL_REF:
154 case LABEL_REF:
155 all_constant = 1;
156 break;
158 case PLUS:
159 /* The interesting case is adding the integer to a sum. Look
160 for constant term in the sum and combine with C. For an
161 integer constant term or a constant term that is not an
162 explicit integer, we combine or group them together anyway.
164 We may not immediately return from the recursive call here, lest
165 all_constant gets lost. */
167 if (CONSTANT_P (XEXP (x, 1)))
169 rtx term = plus_constant (mode, XEXP (x, 1), c, inplace);
170 if (term == const0_rtx)
171 x = XEXP (x, 0);
172 else if (inplace)
173 XEXP (x, 1) = term;
174 else
175 x = gen_rtx_PLUS (mode, XEXP (x, 0), term);
176 c = 0;
178 else if (rtx *const_loc = find_constant_term_loc (&y))
180 if (!inplace)
182 /* We need to be careful since X may be shared and we can't
183 modify it in place. */
184 x = copy_rtx (x);
185 const_loc = find_constant_term_loc (&x);
187 *const_loc = plus_constant (mode, *const_loc, c, true);
188 c = 0;
190 break;
192 default:
193 if (CONST_POLY_INT_P (x))
194 return immed_wide_int_const (const_poly_int_value (x) + c, mode);
195 break;
198 if (maybe_ne (c, 0))
199 x = gen_rtx_PLUS (mode, x, gen_int_mode (c, mode));
201 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
202 return x;
203 else if (all_constant)
204 return gen_rtx_CONST (mode, x);
205 else
206 return x;
209 /* If X is a sum, return a new sum like X but lacking any constant terms.
210 Add all the removed constant terms into *CONSTPTR.
211 X itself is not altered. The result != X if and only if
212 it is not isomorphic to X. */
215 eliminate_constant_term (rtx x, rtx *constptr)
217 rtx x0, x1;
218 rtx tem;
220 if (GET_CODE (x) != PLUS)
221 return x;
223 /* First handle constants appearing at this level explicitly. */
224 if (CONST_INT_P (XEXP (x, 1))
225 && (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
226 XEXP (x, 1))) != 0
227 && CONST_INT_P (tem))
229 *constptr = tem;
230 return eliminate_constant_term (XEXP (x, 0), constptr);
233 tem = const0_rtx;
234 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
235 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
236 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
237 && (tem = simplify_binary_operation (PLUS, GET_MODE (x),
238 *constptr, tem)) != 0
239 && CONST_INT_P (tem))
241 *constptr = tem;
242 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
245 return x;
249 /* Return a copy of X in which all memory references
250 and all constants that involve symbol refs
251 have been replaced with new temporary registers.
252 Also emit code to load the memory locations and constants
253 into those registers.
255 If X contains no such constants or memory references,
256 X itself (not a copy) is returned.
258 If a constant is found in the address that is not a legitimate constant
259 in an insn, it is left alone in the hope that it might be valid in the
260 address.
262 X may contain no arithmetic except addition, subtraction and multiplication.
263 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
265 static rtx
266 break_out_memory_refs (rtx x)
268 if (MEM_P (x)
269 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
270 && GET_MODE (x) != VOIDmode))
271 x = force_reg (GET_MODE (x), x);
272 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
273 || GET_CODE (x) == MULT)
275 rtx op0 = break_out_memory_refs (XEXP (x, 0));
276 rtx op1 = break_out_memory_refs (XEXP (x, 1));
278 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
279 x = simplify_gen_binary (GET_CODE (x), GET_MODE (x), op0, op1);
282 return x;
285 /* Given X, a memory address in address space AS' pointer mode, convert it to
286 an address in the address space's address mode, or vice versa (TO_MODE says
287 which way). We take advantage of the fact that pointers are not allowed to
288 overflow by commuting arithmetic operations over conversions so that address
289 arithmetic insns can be used. IN_CONST is true if this conversion is inside
290 a CONST. NO_EMIT is true if no insns should be emitted, and instead
291 it should return NULL if it can't be simplified without emitting insns. */
294 convert_memory_address_addr_space_1 (scalar_int_mode to_mode ATTRIBUTE_UNUSED,
295 rtx x, addr_space_t as ATTRIBUTE_UNUSED,
296 bool in_const ATTRIBUTE_UNUSED,
297 bool no_emit ATTRIBUTE_UNUSED)
299 #ifndef POINTERS_EXTEND_UNSIGNED
300 gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode);
301 return x;
302 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
303 scalar_int_mode pointer_mode, address_mode, from_mode;
304 rtx temp;
305 enum rtx_code code;
307 /* If X already has the right mode, just return it. */
308 if (GET_MODE (x) == to_mode)
309 return x;
311 pointer_mode = targetm.addr_space.pointer_mode (as);
312 address_mode = targetm.addr_space.address_mode (as);
313 from_mode = to_mode == pointer_mode ? address_mode : pointer_mode;
315 /* Here we handle some special cases. If none of them apply, fall through
316 to the default case. */
317 switch (GET_CODE (x))
319 CASE_CONST_SCALAR_INT:
320 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
321 code = TRUNCATE;
322 else if (POINTERS_EXTEND_UNSIGNED < 0)
323 break;
324 else if (POINTERS_EXTEND_UNSIGNED > 0)
325 code = ZERO_EXTEND;
326 else
327 code = SIGN_EXTEND;
328 temp = simplify_unary_operation (code, to_mode, x, from_mode);
329 if (temp)
330 return temp;
331 break;
333 case SUBREG:
334 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
335 && GET_MODE (SUBREG_REG (x)) == to_mode)
336 return SUBREG_REG (x);
337 break;
339 case LABEL_REF:
340 temp = gen_rtx_LABEL_REF (to_mode, label_ref_label (x));
341 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
342 return temp;
344 case SYMBOL_REF:
345 temp = shallow_copy_rtx (x);
346 PUT_MODE (temp, to_mode);
347 return temp;
349 case CONST:
350 temp = convert_memory_address_addr_space_1 (to_mode, XEXP (x, 0), as,
351 true, no_emit);
352 return temp ? gen_rtx_CONST (to_mode, temp) : temp;
354 case PLUS:
355 case MULT:
356 /* For addition we can safely permute the conversion and addition
357 operation if one operand is a constant and converting the constant
358 does not change it or if one operand is a constant and we are
359 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
360 We can always safely permute them if we are making the address
361 narrower. Inside a CONST RTL, this is safe for both pointers
362 zero or sign extended as pointers cannot wrap. */
363 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
364 || (GET_CODE (x) == PLUS
365 && CONST_INT_P (XEXP (x, 1))
366 && ((in_const && POINTERS_EXTEND_UNSIGNED != 0)
367 || XEXP (x, 1) == convert_memory_address_addr_space_1
368 (to_mode, XEXP (x, 1), as, in_const,
369 no_emit)
370 || POINTERS_EXTEND_UNSIGNED < 0)))
372 temp = convert_memory_address_addr_space_1 (to_mode, XEXP (x, 0),
373 as, in_const, no_emit);
374 return (temp ? gen_rtx_fmt_ee (GET_CODE (x), to_mode,
375 temp, XEXP (x, 1))
376 : temp);
378 break;
380 default:
381 break;
384 if (no_emit)
385 return NULL_RTX;
387 return convert_modes (to_mode, from_mode,
388 x, POINTERS_EXTEND_UNSIGNED);
389 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
392 /* Given X, a memory address in address space AS' pointer mode, convert it to
393 an address in the address space's address mode, or vice versa (TO_MODE says
394 which way). We take advantage of the fact that pointers are not allowed to
395 overflow by commuting arithmetic operations over conversions so that address
396 arithmetic insns can be used. */
399 convert_memory_address_addr_space (scalar_int_mode to_mode, rtx x,
400 addr_space_t as)
402 return convert_memory_address_addr_space_1 (to_mode, x, as, false, false);
406 /* Return something equivalent to X but valid as a memory address for something
407 of mode MODE in the named address space AS. When X is not itself valid,
408 this works by copying X or subexpressions of it into registers. */
411 memory_address_addr_space (machine_mode mode, rtx x, addr_space_t as)
413 rtx oldx = x;
414 scalar_int_mode address_mode = targetm.addr_space.address_mode (as);
416 x = convert_memory_address_addr_space (address_mode, x, as);
418 /* By passing constant addresses through registers
419 we get a chance to cse them. */
420 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
421 x = force_reg (address_mode, x);
423 /* We get better cse by rejecting indirect addressing at this stage.
424 Let the combiner create indirect addresses where appropriate.
425 For now, generate the code so that the subexpressions useful to share
426 are visible. But not if cse won't be done! */
427 else
429 if (! cse_not_expected && !REG_P (x))
430 x = break_out_memory_refs (x);
432 /* At this point, any valid address is accepted. */
433 if (memory_address_addr_space_p (mode, x, as))
434 goto done;
436 /* If it was valid before but breaking out memory refs invalidated it,
437 use it the old way. */
438 if (memory_address_addr_space_p (mode, oldx, as))
440 x = oldx;
441 goto done;
444 /* Perform machine-dependent transformations on X
445 in certain cases. This is not necessary since the code
446 below can handle all possible cases, but machine-dependent
447 transformations can make better code. */
449 rtx orig_x = x;
450 x = targetm.addr_space.legitimize_address (x, oldx, mode, as);
451 if (orig_x != x && memory_address_addr_space_p (mode, x, as))
452 goto done;
455 /* PLUS and MULT can appear in special ways
456 as the result of attempts to make an address usable for indexing.
457 Usually they are dealt with by calling force_operand, below.
458 But a sum containing constant terms is special
459 if removing them makes the sum a valid address:
460 then we generate that address in a register
461 and index off of it. We do this because it often makes
462 shorter code, and because the addresses thus generated
463 in registers often become common subexpressions. */
464 if (GET_CODE (x) == PLUS)
466 rtx constant_term = const0_rtx;
467 rtx y = eliminate_constant_term (x, &constant_term);
468 if (constant_term == const0_rtx
469 || ! memory_address_addr_space_p (mode, y, as))
470 x = force_operand (x, NULL_RTX);
471 else
473 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
474 if (! memory_address_addr_space_p (mode, y, as))
475 x = force_operand (x, NULL_RTX);
476 else
477 x = y;
481 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
482 x = force_operand (x, NULL_RTX);
484 /* If we have a register that's an invalid address,
485 it must be a hard reg of the wrong class. Copy it to a pseudo. */
486 else if (REG_P (x))
487 x = copy_to_reg (x);
489 /* Last resort: copy the value to a register, since
490 the register is a valid address. */
491 else
492 x = force_reg (address_mode, x);
495 done:
497 gcc_assert (memory_address_addr_space_p (mode, x, as));
498 /* If we didn't change the address, we are done. Otherwise, mark
499 a reg as a pointer if we have REG or REG + CONST_INT. */
500 if (oldx == x)
501 return x;
502 else if (REG_P (x))
503 mark_reg_pointer (x, BITS_PER_UNIT);
504 else if (GET_CODE (x) == PLUS
505 && REG_P (XEXP (x, 0))
506 && CONST_INT_P (XEXP (x, 1)))
507 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
509 /* OLDX may have been the address on a temporary. Update the address
510 to indicate that X is now used. */
511 update_temp_slot_address (oldx, x);
513 return x;
516 /* Convert a mem ref into one with a valid memory address.
517 Pass through anything else unchanged. */
520 validize_mem (rtx ref)
522 if (!MEM_P (ref))
523 return ref;
524 ref = use_anchored_address (ref);
525 if (memory_address_addr_space_p (GET_MODE (ref), XEXP (ref, 0),
526 MEM_ADDR_SPACE (ref)))
527 return ref;
529 /* Don't alter REF itself, since that is probably a stack slot. */
530 return replace_equiv_address (ref, XEXP (ref, 0));
533 /* If X is a memory reference to a member of an object block, try rewriting
534 it to use an anchor instead. Return the new memory reference on success
535 and the old one on failure. */
538 use_anchored_address (rtx x)
540 rtx base;
541 HOST_WIDE_INT offset;
542 machine_mode mode;
544 if (!flag_section_anchors)
545 return x;
547 if (!MEM_P (x))
548 return x;
550 /* Split the address into a base and offset. */
551 base = XEXP (x, 0);
552 offset = 0;
553 if (GET_CODE (base) == CONST
554 && GET_CODE (XEXP (base, 0)) == PLUS
555 && CONST_INT_P (XEXP (XEXP (base, 0), 1)))
557 offset += INTVAL (XEXP (XEXP (base, 0), 1));
558 base = XEXP (XEXP (base, 0), 0);
561 /* Check whether BASE is suitable for anchors. */
562 if (GET_CODE (base) != SYMBOL_REF
563 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base)
564 || SYMBOL_REF_ANCHOR_P (base)
565 || SYMBOL_REF_BLOCK (base) == NULL
566 || !targetm.use_anchors_for_symbol_p (base))
567 return x;
569 /* Decide where BASE is going to be. */
570 place_block_symbol (base);
572 /* Get the anchor we need to use. */
573 offset += SYMBOL_REF_BLOCK_OFFSET (base);
574 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset,
575 SYMBOL_REF_TLS_MODEL (base));
577 /* Work out the offset from the anchor. */
578 offset -= SYMBOL_REF_BLOCK_OFFSET (base);
580 /* If we're going to run a CSE pass, force the anchor into a register.
581 We will then be able to reuse registers for several accesses, if the
582 target costs say that that's worthwhile. */
583 mode = GET_MODE (base);
584 if (!cse_not_expected)
585 base = force_reg (mode, base);
587 return replace_equiv_address (x, plus_constant (mode, base, offset));
590 /* Copy the value or contents of X to a new temp reg and return that reg. */
593 copy_to_reg (rtx x)
595 rtx temp = gen_reg_rtx (GET_MODE (x));
597 /* If not an operand, must be an address with PLUS and MULT so
598 do the computation. */
599 if (! general_operand (x, VOIDmode))
600 x = force_operand (x, temp);
602 if (x != temp)
603 emit_move_insn (temp, x);
605 return temp;
608 /* Like copy_to_reg but always give the new register mode Pmode
609 in case X is a constant. */
612 copy_addr_to_reg (rtx x)
614 return copy_to_mode_reg (Pmode, x);
617 /* Like copy_to_reg but always give the new register mode MODE
618 in case X is a constant. */
621 copy_to_mode_reg (machine_mode mode, rtx x)
623 rtx temp = gen_reg_rtx (mode);
625 /* If not an operand, must be an address with PLUS and MULT so
626 do the computation. */
627 if (! general_operand (x, VOIDmode))
628 x = force_operand (x, temp);
630 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
631 if (x != temp)
632 emit_move_insn (temp, x);
633 return temp;
636 /* Load X into a register if it is not already one.
637 Use mode MODE for the register.
638 X should be valid for mode MODE, but it may be a constant which
639 is valid for all integer modes; that's why caller must specify MODE.
641 The caller must not alter the value in the register we return,
642 since we mark it as a "constant" register. */
645 force_reg (machine_mode mode, rtx x)
647 rtx temp, set;
648 rtx_insn *insn;
650 if (REG_P (x))
651 return x;
653 if (general_operand (x, mode))
655 temp = gen_reg_rtx (mode);
656 insn = emit_move_insn (temp, x);
658 else
660 temp = force_operand (x, NULL_RTX);
661 if (REG_P (temp))
662 insn = get_last_insn ();
663 else
665 rtx temp2 = gen_reg_rtx (mode);
666 insn = emit_move_insn (temp2, temp);
667 temp = temp2;
671 /* Let optimizers know that TEMP's value never changes
672 and that X can be substituted for it. Don't get confused
673 if INSN set something else (such as a SUBREG of TEMP). */
674 if (CONSTANT_P (x)
675 && (set = single_set (insn)) != 0
676 && SET_DEST (set) == temp
677 && ! rtx_equal_p (x, SET_SRC (set)))
678 set_unique_reg_note (insn, REG_EQUAL, x);
680 /* Let optimizers know that TEMP is a pointer, and if so, the
681 known alignment of that pointer. */
683 unsigned align = 0;
684 if (GET_CODE (x) == SYMBOL_REF)
686 align = BITS_PER_UNIT;
687 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
688 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
690 else if (GET_CODE (x) == LABEL_REF)
691 align = BITS_PER_UNIT;
692 else if (GET_CODE (x) == CONST
693 && GET_CODE (XEXP (x, 0)) == PLUS
694 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
695 && CONST_INT_P (XEXP (XEXP (x, 0), 1)))
697 rtx s = XEXP (XEXP (x, 0), 0);
698 rtx c = XEXP (XEXP (x, 0), 1);
699 unsigned sa, ca;
701 sa = BITS_PER_UNIT;
702 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
703 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
705 if (INTVAL (c) == 0)
706 align = sa;
707 else
709 ca = ctz_hwi (INTVAL (c)) * BITS_PER_UNIT;
710 align = MIN (sa, ca);
714 if (align || (MEM_P (x) && MEM_POINTER (x)))
715 mark_reg_pointer (temp, align);
718 return temp;
721 /* If X is a memory ref, copy its contents to a new temp reg and return
722 that reg. Otherwise, return X. */
725 force_not_mem (rtx x)
727 rtx temp;
729 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
730 return x;
732 temp = gen_reg_rtx (GET_MODE (x));
734 if (MEM_POINTER (x))
735 REG_POINTER (temp) = 1;
737 emit_move_insn (temp, x);
738 return temp;
741 /* Copy X to TARGET (if it's nonzero and a reg)
742 or to a new temp reg and return that reg.
743 MODE is the mode to use for X in case it is a constant. */
746 copy_to_suggested_reg (rtx x, rtx target, machine_mode mode)
748 rtx temp;
750 if (target && REG_P (target))
751 temp = target;
752 else
753 temp = gen_reg_rtx (mode);
755 emit_move_insn (temp, x);
756 return temp;
759 /* Return the mode to use to pass or return a scalar of TYPE and MODE.
760 PUNSIGNEDP points to the signedness of the type and may be adjusted
761 to show what signedness to use on extension operations.
763 FOR_RETURN is nonzero if the caller is promoting the return value
764 of FNDECL, else it is for promoting args. */
766 machine_mode
767 promote_function_mode (const_tree type, machine_mode mode, int *punsignedp,
768 const_tree funtype, int for_return)
770 /* Called without a type node for a libcall. */
771 if (type == NULL_TREE)
773 if (INTEGRAL_MODE_P (mode))
774 return targetm.calls.promote_function_mode (NULL_TREE, mode,
775 punsignedp, funtype,
776 for_return);
777 else
778 return mode;
781 switch (TREE_CODE (type))
783 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
784 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
785 case POINTER_TYPE: case REFERENCE_TYPE:
786 return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype,
787 for_return);
789 default:
790 return mode;
793 /* Return the mode to use to store a scalar of TYPE and MODE.
794 PUNSIGNEDP points to the signedness of the type and may be adjusted
795 to show what signedness to use on extension operations. */
797 machine_mode
798 promote_mode (const_tree type ATTRIBUTE_UNUSED, machine_mode mode,
799 int *punsignedp ATTRIBUTE_UNUSED)
801 #ifdef PROMOTE_MODE
802 enum tree_code code;
803 int unsignedp;
804 scalar_mode smode;
805 #endif
807 /* For libcalls this is invoked without TYPE from the backends
808 TARGET_PROMOTE_FUNCTION_MODE hooks. Don't do anything in that
809 case. */
810 if (type == NULL_TREE)
811 return mode;
813 /* FIXME: this is the same logic that was there until GCC 4.4, but we
814 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
815 is not defined. The affected targets are M32C, S390, SPARC. */
816 #ifdef PROMOTE_MODE
817 code = TREE_CODE (type);
818 unsignedp = *punsignedp;
820 switch (code)
822 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
823 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
824 /* Values of these types always have scalar mode. */
825 smode = as_a <scalar_mode> (mode);
826 PROMOTE_MODE (smode, unsignedp, type);
827 *punsignedp = unsignedp;
828 return smode;
830 #ifdef POINTERS_EXTEND_UNSIGNED
831 case REFERENCE_TYPE:
832 case POINTER_TYPE:
833 *punsignedp = POINTERS_EXTEND_UNSIGNED;
834 return targetm.addr_space.address_mode
835 (TYPE_ADDR_SPACE (TREE_TYPE (type)));
836 #endif
838 default:
839 return mode;
841 #else
842 return mode;
843 #endif
847 /* Use one of promote_mode or promote_function_mode to find the promoted
848 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
849 of DECL after promotion. */
851 machine_mode
852 promote_decl_mode (const_tree decl, int *punsignedp)
854 tree type = TREE_TYPE (decl);
855 int unsignedp = TYPE_UNSIGNED (type);
856 machine_mode mode = DECL_MODE (decl);
857 machine_mode pmode;
859 if (TREE_CODE (decl) == RESULT_DECL && !DECL_BY_REFERENCE (decl))
860 pmode = promote_function_mode (type, mode, &unsignedp,
861 TREE_TYPE (current_function_decl), 1);
862 else if (TREE_CODE (decl) == RESULT_DECL || TREE_CODE (decl) == PARM_DECL)
863 pmode = promote_function_mode (type, mode, &unsignedp,
864 TREE_TYPE (current_function_decl), 2);
865 else
866 pmode = promote_mode (type, mode, &unsignedp);
868 if (punsignedp)
869 *punsignedp = unsignedp;
870 return pmode;
873 /* Return the promoted mode for name. If it is a named SSA_NAME, it
874 is the same as promote_decl_mode. Otherwise, it is the promoted
875 mode of a temp decl of same type as the SSA_NAME, if we had created
876 one. */
878 machine_mode
879 promote_ssa_mode (const_tree name, int *punsignedp)
881 gcc_assert (TREE_CODE (name) == SSA_NAME);
883 /* Partitions holding parms and results must be promoted as expected
884 by function.c. */
885 if (SSA_NAME_VAR (name)
886 && (TREE_CODE (SSA_NAME_VAR (name)) == PARM_DECL
887 || TREE_CODE (SSA_NAME_VAR (name)) == RESULT_DECL))
889 machine_mode mode = promote_decl_mode (SSA_NAME_VAR (name), punsignedp);
890 if (mode != BLKmode)
891 return mode;
894 tree type = TREE_TYPE (name);
895 int unsignedp = TYPE_UNSIGNED (type);
896 machine_mode mode = TYPE_MODE (type);
898 /* Bypass TYPE_MODE when it maps vector modes to BLKmode. */
899 if (mode == BLKmode)
901 gcc_assert (VECTOR_TYPE_P (type));
902 mode = type->type_common.mode;
905 machine_mode pmode = promote_mode (type, mode, &unsignedp);
906 if (punsignedp)
907 *punsignedp = unsignedp;
909 return pmode;
914 /* Controls the behavior of {anti_,}adjust_stack. */
915 static bool suppress_reg_args_size;
917 /* A helper for adjust_stack and anti_adjust_stack. */
919 static void
920 adjust_stack_1 (rtx adjust, bool anti_p)
922 rtx temp;
923 rtx_insn *insn;
925 /* Hereafter anti_p means subtract_p. */
926 if (!STACK_GROWS_DOWNWARD)
927 anti_p = !anti_p;
929 temp = expand_binop (Pmode,
930 anti_p ? sub_optab : add_optab,
931 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
932 OPTAB_LIB_WIDEN);
934 if (temp != stack_pointer_rtx)
935 insn = emit_move_insn (stack_pointer_rtx, temp);
936 else
938 insn = get_last_insn ();
939 temp = single_set (insn);
940 gcc_assert (temp != NULL && SET_DEST (temp) == stack_pointer_rtx);
943 if (!suppress_reg_args_size)
944 add_args_size_note (insn, stack_pointer_delta);
947 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
948 This pops when ADJUST is positive. ADJUST need not be constant. */
950 void
951 adjust_stack (rtx adjust)
953 if (adjust == const0_rtx)
954 return;
956 /* We expect all variable sized adjustments to be multiple of
957 PREFERRED_STACK_BOUNDARY. */
958 poly_int64 const_adjust;
959 if (poly_int_rtx_p (adjust, &const_adjust))
960 stack_pointer_delta -= const_adjust;
962 adjust_stack_1 (adjust, false);
965 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
966 This pushes when ADJUST is positive. ADJUST need not be constant. */
968 void
969 anti_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, true);
983 /* Round the size of a block to be pushed up to the boundary required
984 by this machine. SIZE is the desired size, which need not be constant. */
986 static rtx
987 round_push (rtx size)
989 rtx align_rtx, alignm1_rtx;
991 if (!SUPPORTS_STACK_ALIGNMENT
992 || crtl->preferred_stack_boundary == MAX_SUPPORTED_STACK_ALIGNMENT)
994 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
996 if (align == 1)
997 return size;
999 if (CONST_INT_P (size))
1001 HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
1003 if (INTVAL (size) != new_size)
1004 size = GEN_INT (new_size);
1005 return size;
1008 align_rtx = GEN_INT (align);
1009 alignm1_rtx = GEN_INT (align - 1);
1011 else
1013 /* If crtl->preferred_stack_boundary might still grow, use
1014 virtual_preferred_stack_boundary_rtx instead. This will be
1015 substituted by the right value in vregs pass and optimized
1016 during combine. */
1017 align_rtx = virtual_preferred_stack_boundary_rtx;
1018 alignm1_rtx = force_operand (plus_constant (Pmode, align_rtx, -1),
1019 NULL_RTX);
1022 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1023 but we know it can't. So add ourselves and then do
1024 TRUNC_DIV_EXPR. */
1025 size = expand_binop (Pmode, add_optab, size, alignm1_rtx,
1026 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1027 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, align_rtx,
1028 NULL_RTX, 1);
1029 size = expand_mult (Pmode, size, align_rtx, NULL_RTX, 1);
1031 return size;
1034 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
1035 to a previously-created save area. If no save area has been allocated,
1036 this function will allocate one. If a save area is specified, it
1037 must be of the proper mode. */
1039 void
1040 emit_stack_save (enum save_level save_level, rtx *psave)
1042 rtx sa = *psave;
1043 /* The default is that we use a move insn and save in a Pmode object. */
1044 rtx_insn *(*fcn) (rtx, rtx) = gen_move_insn;
1045 machine_mode mode = STACK_SAVEAREA_MODE (save_level);
1047 /* See if this machine has anything special to do for this kind of save. */
1048 switch (save_level)
1050 case SAVE_BLOCK:
1051 if (targetm.have_save_stack_block ())
1052 fcn = targetm.gen_save_stack_block;
1053 break;
1054 case SAVE_FUNCTION:
1055 if (targetm.have_save_stack_function ())
1056 fcn = targetm.gen_save_stack_function;
1057 break;
1058 case SAVE_NONLOCAL:
1059 if (targetm.have_save_stack_nonlocal ())
1060 fcn = targetm.gen_save_stack_nonlocal;
1061 break;
1062 default:
1063 break;
1066 /* If there is no save area and we have to allocate one, do so. Otherwise
1067 verify the save area is the proper mode. */
1069 if (sa == 0)
1071 if (mode != VOIDmode)
1073 if (save_level == SAVE_NONLOCAL)
1074 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
1075 else
1076 *psave = sa = gen_reg_rtx (mode);
1080 do_pending_stack_adjust ();
1081 if (sa != 0)
1082 sa = validize_mem (sa);
1083 emit_insn (fcn (sa, stack_pointer_rtx));
1086 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1087 area made by emit_stack_save. If it is zero, we have nothing to do. */
1089 void
1090 emit_stack_restore (enum save_level save_level, rtx sa)
1092 /* The default is that we use a move insn. */
1093 rtx_insn *(*fcn) (rtx, rtx) = gen_move_insn;
1095 /* If stack_realign_drap, the x86 backend emits a prologue that aligns both
1096 STACK_POINTER and HARD_FRAME_POINTER.
1097 If stack_realign_fp, the x86 backend emits a prologue that aligns only
1098 STACK_POINTER. This renders the HARD_FRAME_POINTER unusable for accessing
1099 aligned variables, which is reflected in ix86_can_eliminate.
1100 We normally still have the realigned STACK_POINTER that we can use.
1101 But if there is a stack restore still present at reload, it can trigger
1102 mark_not_eliminable for the STACK_POINTER, leaving no way to eliminate
1103 FRAME_POINTER into a hard reg.
1104 To prevent this situation, we force need_drap if we emit a stack
1105 restore. */
1106 if (SUPPORTS_STACK_ALIGNMENT)
1107 crtl->need_drap = true;
1109 /* See if this machine has anything special to do for this kind of save. */
1110 switch (save_level)
1112 case SAVE_BLOCK:
1113 if (targetm.have_restore_stack_block ())
1114 fcn = targetm.gen_restore_stack_block;
1115 break;
1116 case SAVE_FUNCTION:
1117 if (targetm.have_restore_stack_function ())
1118 fcn = targetm.gen_restore_stack_function;
1119 break;
1120 case SAVE_NONLOCAL:
1121 if (targetm.have_restore_stack_nonlocal ())
1122 fcn = targetm.gen_restore_stack_nonlocal;
1123 break;
1124 default:
1125 break;
1128 if (sa != 0)
1130 sa = validize_mem (sa);
1131 /* These clobbers prevent the scheduler from moving
1132 references to variable arrays below the code
1133 that deletes (pops) the arrays. */
1134 emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
1135 emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx));
1138 discard_pending_stack_adjust ();
1140 emit_insn (fcn (stack_pointer_rtx, sa));
1143 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1144 function. This should be called whenever we allocate or deallocate
1145 dynamic stack space. */
1147 void
1148 update_nonlocal_goto_save_area (void)
1150 tree t_save;
1151 rtx r_save;
1153 /* The nonlocal_goto_save_area object is an array of N pointers. The
1154 first one is used for the frame pointer save; the rest are sized by
1155 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1156 of the stack save area slots. */
1157 t_save = build4 (ARRAY_REF,
1158 TREE_TYPE (TREE_TYPE (cfun->nonlocal_goto_save_area)),
1159 cfun->nonlocal_goto_save_area,
1160 integer_one_node, NULL_TREE, NULL_TREE);
1161 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1163 emit_stack_save (SAVE_NONLOCAL, &r_save);
1166 /* Record a new stack level for the current function. This should be called
1167 whenever we allocate or deallocate dynamic stack space. */
1169 void
1170 record_new_stack_level (void)
1172 /* Record the new stack level for nonlocal gotos. */
1173 if (cfun->nonlocal_goto_save_area)
1174 update_nonlocal_goto_save_area ();
1176 /* Record the new stack level for SJLJ exceptions. */
1177 if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ)
1178 update_sjlj_context ();
1181 /* Return an rtx doing runtime alignment to REQUIRED_ALIGN on TARGET. */
1182 static rtx
1183 align_dynamic_address (rtx target, unsigned required_align)
1185 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1186 but we know it can't. So add ourselves and then do
1187 TRUNC_DIV_EXPR. */
1188 target = expand_binop (Pmode, add_optab, target,
1189 gen_int_mode (required_align / BITS_PER_UNIT - 1,
1190 Pmode),
1191 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1192 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1193 gen_int_mode (required_align / BITS_PER_UNIT,
1194 Pmode),
1195 NULL_RTX, 1);
1196 target = expand_mult (Pmode, target,
1197 gen_int_mode (required_align / BITS_PER_UNIT,
1198 Pmode),
1199 NULL_RTX, 1);
1201 return target;
1204 /* Return an rtx through *PSIZE, representing the size of an area of memory to
1205 be dynamically pushed on the stack.
1207 *PSIZE is an rtx representing the size of the area.
1209 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1210 parameter may be zero. If so, a proper value will be extracted
1211 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1213 REQUIRED_ALIGN is the alignment (in bits) required for the region
1214 of memory.
1216 If PSTACK_USAGE_SIZE is not NULL it points to a value that is increased for
1217 the additional size returned. */
1218 void
1219 get_dynamic_stack_size (rtx *psize, unsigned size_align,
1220 unsigned required_align,
1221 HOST_WIDE_INT *pstack_usage_size)
1223 rtx size = *psize;
1225 /* Ensure the size is in the proper mode. */
1226 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1227 size = convert_to_mode (Pmode, size, 1);
1229 if (CONST_INT_P (size))
1231 unsigned HOST_WIDE_INT lsb;
1233 lsb = INTVAL (size);
1234 lsb &= -lsb;
1236 /* Watch out for overflow truncating to "unsigned". */
1237 if (lsb > UINT_MAX / BITS_PER_UNIT)
1238 size_align = 1u << (HOST_BITS_PER_INT - 1);
1239 else
1240 size_align = (unsigned)lsb * BITS_PER_UNIT;
1242 else if (size_align < BITS_PER_UNIT)
1243 size_align = BITS_PER_UNIT;
1245 /* We can't attempt to minimize alignment necessary, because we don't
1246 know the final value of preferred_stack_boundary yet while executing
1247 this code. */
1248 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
1249 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1251 /* We will need to ensure that the address we return is aligned to
1252 REQUIRED_ALIGN. At this point in the compilation, we don't always
1253 know the final value of the STACK_DYNAMIC_OFFSET used in function.c
1254 (it might depend on the size of the outgoing parameter lists, for
1255 example), so we must preventively align the value. We leave space
1256 in SIZE for the hole that might result from the alignment operation. */
1258 unsigned known_align = REGNO_POINTER_ALIGN (VIRTUAL_STACK_DYNAMIC_REGNUM);
1259 if (known_align == 0)
1260 known_align = BITS_PER_UNIT;
1261 if (required_align > known_align)
1263 unsigned extra = (required_align - known_align) / BITS_PER_UNIT;
1264 size = plus_constant (Pmode, size, extra);
1265 size = force_operand (size, NULL_RTX);
1266 if (size_align > known_align)
1267 size_align = known_align;
1269 if (flag_stack_usage_info && pstack_usage_size)
1270 *pstack_usage_size += extra;
1273 /* Round the size to a multiple of the required stack alignment.
1274 Since the stack is presumed to be rounded before this allocation,
1275 this will maintain the required alignment.
1277 If the stack grows downward, we could save an insn by subtracting
1278 SIZE from the stack pointer and then aligning the stack pointer.
1279 The problem with this is that the stack pointer may be unaligned
1280 between the execution of the subtraction and alignment insns and
1281 some machines do not allow this. Even on those that do, some
1282 signal handlers malfunction if a signal should occur between those
1283 insns. Since this is an extremely rare event, we have no reliable
1284 way of knowing which systems have this problem. So we avoid even
1285 momentarily mis-aligning the stack. */
1286 if (size_align % MAX_SUPPORTED_STACK_ALIGNMENT != 0)
1288 size = round_push (size);
1290 if (flag_stack_usage_info && pstack_usage_size)
1292 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
1293 *pstack_usage_size =
1294 (*pstack_usage_size + align - 1) / align * align;
1298 *psize = size;
1301 /* Return the number of bytes to "protect" on the stack for -fstack-check.
1303 "protect" in the context of -fstack-check means how many bytes we
1304 should always ensure are available on the stack. More importantly
1305 this is how many bytes are skipped when probing the stack.
1307 On some targets we want to reuse the -fstack-check prologue support
1308 to give a degree of protection against stack clashing style attacks.
1310 In that scenario we do not want to skip bytes before probing as that
1311 would render the stack clash protections useless.
1313 So we never use STACK_CHECK_PROTECT directly. Instead we indirect though
1314 this helper which allows us to provide different values for
1315 -fstack-check and -fstack-clash-protection. */
1316 HOST_WIDE_INT
1317 get_stack_check_protect (void)
1319 if (flag_stack_clash_protection)
1320 return 0;
1321 return STACK_CHECK_PROTECT;
1324 /* Return an rtx representing the address of an area of memory dynamically
1325 pushed on the stack.
1327 Any required stack pointer alignment is preserved.
1329 SIZE is an rtx representing the size of the area.
1331 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1332 parameter may be zero. If so, a proper value will be extracted
1333 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1335 REQUIRED_ALIGN is the alignment (in bits) required for the region
1336 of memory.
1338 MAX_SIZE is an upper bound for SIZE, if SIZE is not constant, or -1 if
1339 no such upper bound is known.
1341 If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
1342 stack space allocated by the generated code cannot be added with itself
1343 in the course of the execution of the function. It is always safe to
1344 pass FALSE here and the following criterion is sufficient in order to
1345 pass TRUE: every path in the CFG that starts at the allocation point and
1346 loops to it executes the associated deallocation code. */
1349 allocate_dynamic_stack_space (rtx size, unsigned size_align,
1350 unsigned required_align,
1351 HOST_WIDE_INT max_size,
1352 bool cannot_accumulate)
1354 HOST_WIDE_INT stack_usage_size = -1;
1355 rtx_code_label *final_label;
1356 rtx final_target, target;
1358 /* If we're asking for zero bytes, it doesn't matter what we point
1359 to since we can't dereference it. But return a reasonable
1360 address anyway. */
1361 if (size == const0_rtx)
1362 return virtual_stack_dynamic_rtx;
1364 /* Otherwise, show we're calling alloca or equivalent. */
1365 cfun->calls_alloca = 1;
1367 /* If stack usage info is requested, look into the size we are passed.
1368 We need to do so this early to avoid the obfuscation that may be
1369 introduced later by the various alignment operations. */
1370 if (flag_stack_usage_info)
1372 if (CONST_INT_P (size))
1373 stack_usage_size = INTVAL (size);
1374 else if (REG_P (size))
1376 /* Look into the last emitted insn and see if we can deduce
1377 something for the register. */
1378 rtx_insn *insn;
1379 rtx set, note;
1380 insn = get_last_insn ();
1381 if ((set = single_set (insn)) && rtx_equal_p (SET_DEST (set), size))
1383 if (CONST_INT_P (SET_SRC (set)))
1384 stack_usage_size = INTVAL (SET_SRC (set));
1385 else if ((note = find_reg_equal_equiv_note (insn))
1386 && CONST_INT_P (XEXP (note, 0)))
1387 stack_usage_size = INTVAL (XEXP (note, 0));
1391 /* If the size is not constant, try the maximum size. */
1392 if (stack_usage_size < 0)
1393 stack_usage_size = max_size;
1395 /* If the size is still not constant, we can't say anything. */
1396 if (stack_usage_size < 0)
1398 current_function_has_unbounded_dynamic_stack_size = 1;
1399 stack_usage_size = 0;
1403 get_dynamic_stack_size (&size, size_align, required_align, &stack_usage_size);
1405 target = gen_reg_rtx (Pmode);
1407 /* The size is supposed to be fully adjusted at this point so record it
1408 if stack usage info is requested. */
1409 if (flag_stack_usage_info)
1411 current_function_dynamic_stack_size += stack_usage_size;
1413 /* ??? This is gross but the only safe stance in the absence
1414 of stack usage oriented flow analysis. */
1415 if (!cannot_accumulate)
1416 current_function_has_unbounded_dynamic_stack_size = 1;
1419 do_pending_stack_adjust ();
1421 final_label = NULL;
1422 final_target = NULL_RTX;
1424 /* If we are splitting the stack, we need to ask the backend whether
1425 there is enough room on the current stack. If there isn't, or if
1426 the backend doesn't know how to tell is, then we need to call a
1427 function to allocate memory in some other way. This memory will
1428 be released when we release the current stack segment. The
1429 effect is that stack allocation becomes less efficient, but at
1430 least it doesn't cause a stack overflow. */
1431 if (flag_split_stack)
1433 rtx_code_label *available_label;
1434 rtx ask, space, func;
1436 available_label = NULL;
1438 if (targetm.have_split_stack_space_check ())
1440 available_label = gen_label_rtx ();
1442 /* This instruction will branch to AVAILABLE_LABEL if there
1443 are SIZE bytes available on the stack. */
1444 emit_insn (targetm.gen_split_stack_space_check
1445 (size, available_label));
1448 /* The __morestack_allocate_stack_space function will allocate
1449 memory using malloc. If the alignment of the memory returned
1450 by malloc does not meet REQUIRED_ALIGN, we increase SIZE to
1451 make sure we allocate enough space. */
1452 if (MALLOC_ABI_ALIGNMENT >= required_align)
1453 ask = size;
1454 else
1455 ask = expand_binop (Pmode, add_optab, size,
1456 gen_int_mode (required_align / BITS_PER_UNIT - 1,
1457 Pmode),
1458 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1460 func = init_one_libfunc ("__morestack_allocate_stack_space");
1462 space = emit_library_call_value (func, target, LCT_NORMAL, Pmode,
1463 ask, Pmode);
1465 if (available_label == NULL_RTX)
1466 return space;
1468 final_target = gen_reg_rtx (Pmode);
1470 emit_move_insn (final_target, space);
1472 final_label = gen_label_rtx ();
1473 emit_jump (final_label);
1475 emit_label (available_label);
1478 /* We ought to be called always on the toplevel and stack ought to be aligned
1479 properly. */
1480 gcc_assert (multiple_p (stack_pointer_delta,
1481 PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT));
1483 /* If needed, check that we have the required amount of stack. Take into
1484 account what has already been checked. */
1485 if (STACK_CHECK_MOVING_SP)
1487 else if (flag_stack_check == GENERIC_STACK_CHECK)
1488 probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE,
1489 size);
1490 else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
1491 probe_stack_range (get_stack_check_protect (), size);
1493 /* Don't let anti_adjust_stack emit notes. */
1494 suppress_reg_args_size = true;
1496 /* Perform the required allocation from the stack. Some systems do
1497 this differently than simply incrementing/decrementing from the
1498 stack pointer, such as acquiring the space by calling malloc(). */
1499 if (targetm.have_allocate_stack ())
1501 struct expand_operand ops[2];
1502 /* We don't have to check against the predicate for operand 0 since
1503 TARGET is known to be a pseudo of the proper mode, which must
1504 be valid for the operand. */
1505 create_fixed_operand (&ops[0], target);
1506 create_convert_operand_to (&ops[1], size, STACK_SIZE_MODE, true);
1507 expand_insn (targetm.code_for_allocate_stack, 2, ops);
1509 else
1511 poly_int64 saved_stack_pointer_delta;
1513 if (!STACK_GROWS_DOWNWARD)
1514 emit_move_insn (target, virtual_stack_dynamic_rtx);
1516 /* Check stack bounds if necessary. */
1517 if (crtl->limit_stack)
1519 rtx available;
1520 rtx_code_label *space_available = gen_label_rtx ();
1521 if (STACK_GROWS_DOWNWARD)
1522 available = expand_binop (Pmode, sub_optab,
1523 stack_pointer_rtx, stack_limit_rtx,
1524 NULL_RTX, 1, OPTAB_WIDEN);
1525 else
1526 available = expand_binop (Pmode, sub_optab,
1527 stack_limit_rtx, stack_pointer_rtx,
1528 NULL_RTX, 1, OPTAB_WIDEN);
1530 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1531 space_available);
1532 if (targetm.have_trap ())
1533 emit_insn (targetm.gen_trap ());
1534 else
1535 error ("stack limits not supported on this target");
1536 emit_barrier ();
1537 emit_label (space_available);
1540 saved_stack_pointer_delta = stack_pointer_delta;
1542 if (flag_stack_check && STACK_CHECK_MOVING_SP)
1543 anti_adjust_stack_and_probe (size, false);
1544 else if (flag_stack_clash_protection)
1545 anti_adjust_stack_and_probe_stack_clash (size);
1546 else
1547 anti_adjust_stack (size);
1549 /* Even if size is constant, don't modify stack_pointer_delta.
1550 The constant size alloca should preserve
1551 crtl->preferred_stack_boundary alignment. */
1552 stack_pointer_delta = saved_stack_pointer_delta;
1554 if (STACK_GROWS_DOWNWARD)
1555 emit_move_insn (target, virtual_stack_dynamic_rtx);
1558 suppress_reg_args_size = false;
1560 /* Finish up the split stack handling. */
1561 if (final_label != NULL_RTX)
1563 gcc_assert (flag_split_stack);
1564 emit_move_insn (final_target, target);
1565 emit_label (final_label);
1566 target = final_target;
1569 target = align_dynamic_address (target, required_align);
1571 /* Now that we've committed to a return value, mark its alignment. */
1572 mark_reg_pointer (target, required_align);
1574 /* Record the new stack level. */
1575 record_new_stack_level ();
1577 return target;
1580 /* Return an rtx representing the address of an area of memory already
1581 statically pushed onto the stack in the virtual stack vars area. (It is
1582 assumed that the area is allocated in the function prologue.)
1584 Any required stack pointer alignment is preserved.
1586 OFFSET is the offset of the area into the virtual stack vars area.
1588 REQUIRED_ALIGN is the alignment (in bits) required for the region
1589 of memory. */
1592 get_dynamic_stack_base (poly_int64 offset, unsigned required_align)
1594 rtx target;
1596 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
1597 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1599 target = gen_reg_rtx (Pmode);
1600 emit_move_insn (target, virtual_stack_vars_rtx);
1601 target = expand_binop (Pmode, add_optab, target,
1602 gen_int_mode (offset, Pmode),
1603 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1604 target = align_dynamic_address (target, required_align);
1606 /* Now that we've committed to a return value, mark its alignment. */
1607 mark_reg_pointer (target, required_align);
1609 return target;
1612 /* A front end may want to override GCC's stack checking by providing a
1613 run-time routine to call to check the stack, so provide a mechanism for
1614 calling that routine. */
1616 static GTY(()) rtx stack_check_libfunc;
1618 void
1619 set_stack_check_libfunc (const char *libfunc_name)
1621 gcc_assert (stack_check_libfunc == NULL_RTX);
1622 stack_check_libfunc = gen_rtx_SYMBOL_REF (Pmode, libfunc_name);
1625 /* Emit one stack probe at ADDRESS, an address within the stack. */
1627 void
1628 emit_stack_probe (rtx address)
1630 if (targetm.have_probe_stack_address ())
1632 struct expand_operand ops[1];
1633 insn_code icode = targetm.code_for_probe_stack_address;
1634 create_address_operand (ops, address);
1635 maybe_legitimize_operands (icode, 0, 1, ops);
1636 expand_insn (icode, 1, ops);
1638 else
1640 rtx memref = gen_rtx_MEM (word_mode, address);
1642 MEM_VOLATILE_P (memref) = 1;
1643 memref = validize_mem (memref);
1645 /* See if we have an insn to probe the stack. */
1646 if (targetm.have_probe_stack ())
1647 emit_insn (targetm.gen_probe_stack (memref));
1648 else
1649 emit_move_insn (memref, const0_rtx);
1653 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1654 FIRST is a constant and size is a Pmode RTX. These are offsets from
1655 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
1656 or subtract them from the stack pointer. */
1658 #define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
1660 #if STACK_GROWS_DOWNWARD
1661 #define STACK_GROW_OP MINUS
1662 #define STACK_GROW_OPTAB sub_optab
1663 #define STACK_GROW_OFF(off) -(off)
1664 #else
1665 #define STACK_GROW_OP PLUS
1666 #define STACK_GROW_OPTAB add_optab
1667 #define STACK_GROW_OFF(off) (off)
1668 #endif
1670 void
1671 probe_stack_range (HOST_WIDE_INT first, rtx size)
1673 /* First ensure SIZE is Pmode. */
1674 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1675 size = convert_to_mode (Pmode, size, 1);
1677 /* Next see if we have a function to check the stack. */
1678 if (stack_check_libfunc)
1680 rtx addr = memory_address (Pmode,
1681 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1682 stack_pointer_rtx,
1683 plus_constant (Pmode,
1684 size, first)));
1685 emit_library_call (stack_check_libfunc, LCT_THROW, VOIDmode,
1686 addr, Pmode);
1689 /* Next see if we have an insn to check the stack. */
1690 else if (targetm.have_check_stack ())
1692 struct expand_operand ops[1];
1693 rtx addr = memory_address (Pmode,
1694 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1695 stack_pointer_rtx,
1696 plus_constant (Pmode,
1697 size, first)));
1698 bool success;
1699 create_input_operand (&ops[0], addr, Pmode);
1700 success = maybe_expand_insn (targetm.code_for_check_stack, 1, ops);
1701 gcc_assert (success);
1704 /* Otherwise we have to generate explicit probes. If we have a constant
1705 small number of them to generate, that's the easy case. */
1706 else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
1708 HOST_WIDE_INT isize = INTVAL (size), i;
1709 rtx addr;
1711 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
1712 it exceeds SIZE. If only one probe is needed, this will not
1713 generate any code. Then probe at FIRST + SIZE. */
1714 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
1716 addr = memory_address (Pmode,
1717 plus_constant (Pmode, stack_pointer_rtx,
1718 STACK_GROW_OFF (first + i)));
1719 emit_stack_probe (addr);
1722 addr = memory_address (Pmode,
1723 plus_constant (Pmode, stack_pointer_rtx,
1724 STACK_GROW_OFF (first + isize)));
1725 emit_stack_probe (addr);
1728 /* In the variable case, do the same as above, but in a loop. Note that we
1729 must be extra careful with variables wrapping around because we might be
1730 at the very top (or the very bottom) of the address space and we have to
1731 be able to handle this case properly; in particular, we use an equality
1732 test for the loop condition. */
1733 else
1735 rtx rounded_size, rounded_size_op, test_addr, last_addr, temp;
1736 rtx_code_label *loop_lab = gen_label_rtx ();
1737 rtx_code_label *end_lab = gen_label_rtx ();
1739 /* Step 1: round SIZE to the previous multiple of the interval. */
1741 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1742 rounded_size
1743 = simplify_gen_binary (AND, Pmode, size,
1744 gen_int_mode (-PROBE_INTERVAL, Pmode));
1745 rounded_size_op = force_operand (rounded_size, NULL_RTX);
1748 /* Step 2: compute initial and final value of the loop counter. */
1750 /* TEST_ADDR = SP + FIRST. */
1751 test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1752 stack_pointer_rtx,
1753 gen_int_mode (first, Pmode)),
1754 NULL_RTX);
1756 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
1757 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1758 test_addr,
1759 rounded_size_op), NULL_RTX);
1762 /* Step 3: the loop
1764 while (TEST_ADDR != LAST_ADDR)
1766 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
1767 probe at TEST_ADDR
1770 probes at FIRST + N * PROBE_INTERVAL for values of N from 1
1771 until it is equal to ROUNDED_SIZE. */
1773 emit_label (loop_lab);
1775 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
1776 emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1,
1777 end_lab);
1779 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
1780 temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr,
1781 gen_int_mode (PROBE_INTERVAL, Pmode), test_addr,
1782 1, OPTAB_WIDEN);
1784 gcc_assert (temp == test_addr);
1786 /* Probe at TEST_ADDR. */
1787 emit_stack_probe (test_addr);
1789 emit_jump (loop_lab);
1791 emit_label (end_lab);
1794 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
1795 that SIZE is equal to ROUNDED_SIZE. */
1797 /* TEMP = SIZE - ROUNDED_SIZE. */
1798 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
1799 if (temp != const0_rtx)
1801 rtx addr;
1803 if (CONST_INT_P (temp))
1805 /* Use [base + disp} addressing mode if supported. */
1806 HOST_WIDE_INT offset = INTVAL (temp);
1807 addr = memory_address (Pmode,
1808 plus_constant (Pmode, last_addr,
1809 STACK_GROW_OFF (offset)));
1811 else
1813 /* Manual CSE if the difference is not known at compile-time. */
1814 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
1815 addr = memory_address (Pmode,
1816 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1817 last_addr, temp));
1820 emit_stack_probe (addr);
1824 /* Make sure nothing is scheduled before we are done. */
1825 emit_insn (gen_blockage ());
1828 /* Compute parameters for stack clash probing a dynamic stack
1829 allocation of SIZE bytes.
1831 We compute ROUNDED_SIZE, LAST_ADDR, RESIDUAL and PROBE_INTERVAL.
1833 Additionally we conditionally dump the type of probing that will
1834 be needed given the values computed. */
1836 void
1837 compute_stack_clash_protection_loop_data (rtx *rounded_size, rtx *last_addr,
1838 rtx *residual,
1839 HOST_WIDE_INT *probe_interval,
1840 rtx size)
1842 /* Round SIZE down to STACK_CLASH_PROTECTION_PROBE_INTERVAL */
1843 *probe_interval
1844 = 1 << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL);
1845 *rounded_size = simplify_gen_binary (AND, Pmode, size,
1846 GEN_INT (-*probe_interval));
1848 /* Compute the value of the stack pointer for the last iteration.
1849 It's just SP + ROUNDED_SIZE. */
1850 rtx rounded_size_op = force_operand (*rounded_size, NULL_RTX);
1851 *last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1852 stack_pointer_rtx,
1853 rounded_size_op),
1854 NULL_RTX);
1856 /* Compute any residuals not allocated by the loop above. Residuals
1857 are just the ROUNDED_SIZE - SIZE. */
1858 *residual = simplify_gen_binary (MINUS, Pmode, size, *rounded_size);
1860 /* Dump key information to make writing tests easy. */
1861 if (dump_file)
1863 if (*rounded_size == CONST0_RTX (Pmode))
1864 fprintf (dump_file,
1865 "Stack clash skipped dynamic allocation and probing loop.\n");
1866 else if (CONST_INT_P (*rounded_size)
1867 && INTVAL (*rounded_size) <= 4 * *probe_interval)
1868 fprintf (dump_file,
1869 "Stack clash dynamic allocation and probing inline.\n");
1870 else if (CONST_INT_P (*rounded_size))
1871 fprintf (dump_file,
1872 "Stack clash dynamic allocation and probing in "
1873 "rotated loop.\n");
1874 else
1875 fprintf (dump_file,
1876 "Stack clash dynamic allocation and probing in loop.\n");
1878 if (*residual != CONST0_RTX (Pmode))
1879 fprintf (dump_file,
1880 "Stack clash dynamic allocation and probing residuals.\n");
1881 else
1882 fprintf (dump_file,
1883 "Stack clash skipped dynamic allocation and "
1884 "probing residuals.\n");
1888 /* Emit the start of an allocate/probe loop for stack
1889 clash protection.
1891 LOOP_LAB and END_LAB are returned for use when we emit the
1892 end of the loop.
1894 LAST addr is the value for SP which stops the loop. */
1895 void
1896 emit_stack_clash_protection_probe_loop_start (rtx *loop_lab,
1897 rtx *end_lab,
1898 rtx last_addr,
1899 bool rotated)
1901 /* Essentially we want to emit any setup code, the top of loop
1902 label and the comparison at the top of the loop. */
1903 *loop_lab = gen_label_rtx ();
1904 *end_lab = gen_label_rtx ();
1906 emit_label (*loop_lab);
1907 if (!rotated)
1908 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
1909 Pmode, 1, *end_lab);
1912 /* Emit the end of a stack clash probing loop.
1914 This consists of just the jump back to LOOP_LAB and
1915 emitting END_LOOP after the loop. */
1917 void
1918 emit_stack_clash_protection_probe_loop_end (rtx loop_lab, rtx end_loop,
1919 rtx last_addr, bool rotated)
1921 if (rotated)
1922 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, NE, NULL_RTX,
1923 Pmode, 1, loop_lab);
1924 else
1925 emit_jump (loop_lab);
1927 emit_label (end_loop);
1931 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
1932 while probing it. This pushes when SIZE is positive. SIZE need not
1933 be constant.
1935 This is subtly different than anti_adjust_stack_and_probe to try and
1936 prevent stack-clash attacks
1938 1. It must assume no knowledge of the probing state, any allocation
1939 must probe.
1941 Consider the case of a 1 byte alloca in a loop. If the sum of the
1942 allocations is large, then this could be used to jump the guard if
1943 probes were not emitted.
1945 2. It never skips probes, whereas anti_adjust_stack_and_probe will
1946 skip probes on the first couple PROBE_INTERVALs on the assumption
1947 they're done elsewhere.
1949 3. It only allocates and probes SIZE bytes, it does not need to
1950 allocate/probe beyond that because this probing style does not
1951 guarantee signal handling capability if the guard is hit. */
1953 static void
1954 anti_adjust_stack_and_probe_stack_clash (rtx size)
1956 /* First ensure SIZE is Pmode. */
1957 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1958 size = convert_to_mode (Pmode, size, 1);
1960 /* We can get here with a constant size on some targets. */
1961 rtx rounded_size, last_addr, residual;
1962 HOST_WIDE_INT probe_interval;
1963 compute_stack_clash_protection_loop_data (&rounded_size, &last_addr,
1964 &residual, &probe_interval, size);
1966 if (rounded_size != CONST0_RTX (Pmode))
1968 if (CONST_INT_P (rounded_size)
1969 && INTVAL (rounded_size) <= 4 * probe_interval)
1971 for (HOST_WIDE_INT i = 0;
1972 i < INTVAL (rounded_size);
1973 i += probe_interval)
1975 anti_adjust_stack (GEN_INT (probe_interval));
1977 /* The prologue does not probe residuals. Thus the offset
1978 here to probe just beyond what the prologue had already
1979 allocated. */
1980 emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
1981 (probe_interval
1982 - GET_MODE_SIZE (word_mode))));
1983 emit_insn (gen_blockage ());
1986 else
1988 rtx loop_lab, end_loop;
1989 bool rotate_loop = CONST_INT_P (rounded_size);
1990 emit_stack_clash_protection_probe_loop_start (&loop_lab, &end_loop,
1991 last_addr, rotate_loop);
1993 anti_adjust_stack (GEN_INT (probe_interval));
1995 /* The prologue does not probe residuals. Thus the offset here
1996 to probe just beyond what the prologue had already allocated. */
1997 emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
1998 (probe_interval
1999 - GET_MODE_SIZE (word_mode))));
2001 emit_stack_clash_protection_probe_loop_end (loop_lab, end_loop,
2002 last_addr, rotate_loop);
2003 emit_insn (gen_blockage ());
2007 if (residual != CONST0_RTX (Pmode))
2009 rtx label = NULL_RTX;
2010 /* RESIDUAL could be zero at runtime and in that case *sp could
2011 hold live data. Furthermore, we do not want to probe into the
2012 red zone.
2014 Go ahead and just guard the probe at *sp on RESIDUAL != 0 at
2015 runtime if RESIDUAL is not a compile time constant. */
2016 if (!CONST_INT_P (residual))
2018 label = gen_label_rtx ();
2019 emit_cmp_and_jump_insns (residual, CONST0_RTX (GET_MODE (residual)),
2020 EQ, NULL_RTX, Pmode, 1, label);
2023 rtx x = force_reg (Pmode, plus_constant (Pmode, residual,
2024 -GET_MODE_SIZE (word_mode)));
2025 anti_adjust_stack (residual);
2026 emit_stack_probe (gen_rtx_PLUS (Pmode, stack_pointer_rtx, x));
2027 emit_insn (gen_blockage ());
2028 if (!CONST_INT_P (residual))
2029 emit_label (label);
2032 /* Some targets make optimistic assumptions in their prologues about
2033 how the caller may have probed the stack. Make sure we honor
2034 those assumptions when needed. */
2035 if (size != CONST0_RTX (Pmode)
2036 && targetm.stack_clash_protection_final_dynamic_probe (residual))
2038 /* SIZE could be zero at runtime and in that case *sp could hold
2039 live data. Furthermore, we don't want to probe into the red
2040 zone.
2042 Go ahead and just guard the probe at *sp on SIZE != 0 at runtime
2043 if SIZE is not a compile time constant. */
2044 rtx label = NULL_RTX;
2045 if (!CONST_INT_P (size))
2047 label = gen_label_rtx ();
2048 emit_cmp_and_jump_insns (size, CONST0_RTX (GET_MODE (size)),
2049 EQ, NULL_RTX, Pmode, 1, label);
2052 emit_stack_probe (stack_pointer_rtx);
2053 emit_insn (gen_blockage ());
2054 if (!CONST_INT_P (size))
2055 emit_label (label);
2060 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
2061 while probing it. This pushes when SIZE is positive. SIZE need not
2062 be constant. If ADJUST_BACK is true, adjust back the stack pointer
2063 by plus SIZE at the end. */
2065 void
2066 anti_adjust_stack_and_probe (rtx size, bool adjust_back)
2068 /* We skip the probe for the first interval + a small dope of 4 words and
2069 probe that many bytes past the specified size to maintain a protection
2070 area at the botton of the stack. */
2071 const int dope = 4 * UNITS_PER_WORD;
2073 /* First ensure SIZE is Pmode. */
2074 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
2075 size = convert_to_mode (Pmode, size, 1);
2077 /* If we have a constant small number of probes to generate, that's the
2078 easy case. */
2079 if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
2081 HOST_WIDE_INT isize = INTVAL (size), i;
2082 bool first_probe = true;
2084 /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
2085 values of N from 1 until it exceeds SIZE. If only one probe is
2086 needed, this will not generate any code. Then adjust and probe
2087 to PROBE_INTERVAL + SIZE. */
2088 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
2090 if (first_probe)
2092 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope));
2093 first_probe = false;
2095 else
2096 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
2097 emit_stack_probe (stack_pointer_rtx);
2100 if (first_probe)
2101 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
2102 else
2103 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL - i));
2104 emit_stack_probe (stack_pointer_rtx);
2107 /* In the variable case, do the same as above, but in a loop. Note that we
2108 must be extra careful with variables wrapping around because we might be
2109 at the very top (or the very bottom) of the address space and we have to
2110 be able to handle this case properly; in particular, we use an equality
2111 test for the loop condition. */
2112 else
2114 rtx rounded_size, rounded_size_op, last_addr, temp;
2115 rtx_code_label *loop_lab = gen_label_rtx ();
2116 rtx_code_label *end_lab = gen_label_rtx ();
2119 /* Step 1: round SIZE to the previous multiple of the interval. */
2121 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
2122 rounded_size
2123 = simplify_gen_binary (AND, Pmode, size,
2124 gen_int_mode (-PROBE_INTERVAL, Pmode));
2125 rounded_size_op = force_operand (rounded_size, NULL_RTX);
2128 /* Step 2: compute initial and final value of the loop counter. */
2130 /* SP = SP_0 + PROBE_INTERVAL. */
2131 anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
2133 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
2134 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
2135 stack_pointer_rtx,
2136 rounded_size_op), NULL_RTX);
2139 /* Step 3: the loop
2141 while (SP != LAST_ADDR)
2143 SP = SP + PROBE_INTERVAL
2144 probe at SP
2147 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
2148 values of N from 1 until it is equal to ROUNDED_SIZE. */
2150 emit_label (loop_lab);
2152 /* Jump to END_LAB if SP == LAST_ADDR. */
2153 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
2154 Pmode, 1, end_lab);
2156 /* SP = SP + PROBE_INTERVAL and probe at SP. */
2157 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
2158 emit_stack_probe (stack_pointer_rtx);
2160 emit_jump (loop_lab);
2162 emit_label (end_lab);
2165 /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
2166 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
2168 /* TEMP = SIZE - ROUNDED_SIZE. */
2169 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
2170 if (temp != const0_rtx)
2172 /* Manual CSE if the difference is not known at compile-time. */
2173 if (GET_CODE (temp) != CONST_INT)
2174 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
2175 anti_adjust_stack (temp);
2176 emit_stack_probe (stack_pointer_rtx);
2180 /* Adjust back and account for the additional first interval. */
2181 if (adjust_back)
2182 adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
2183 else
2184 adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
2187 /* Return an rtx representing the register or memory location
2188 in which a scalar value of data type VALTYPE
2189 was returned by a function call to function FUNC.
2190 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
2191 function is known, otherwise 0.
2192 OUTGOING is 1 if on a machine with register windows this function
2193 should return the register in which the function will put its result
2194 and 0 otherwise. */
2197 hard_function_value (const_tree valtype, const_tree func, const_tree fntype,
2198 int outgoing ATTRIBUTE_UNUSED)
2200 rtx val;
2202 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
2204 if (REG_P (val)
2205 && GET_MODE (val) == BLKmode)
2207 unsigned HOST_WIDE_INT bytes = arg_int_size_in_bytes (valtype);
2208 opt_scalar_int_mode tmpmode;
2210 /* int_size_in_bytes can return -1. We don't need a check here
2211 since the value of bytes will then be large enough that no
2212 mode will match anyway. */
2214 FOR_EACH_MODE_IN_CLASS (tmpmode, MODE_INT)
2216 /* Have we found a large enough mode? */
2217 if (GET_MODE_SIZE (tmpmode.require ()) >= bytes)
2218 break;
2221 PUT_MODE (val, tmpmode.require ());
2223 return val;
2226 /* Return an rtx representing the register or memory location
2227 in which a scalar value of mode MODE was returned by a library call. */
2230 hard_libcall_value (machine_mode mode, rtx fun)
2232 return targetm.calls.libcall_value (mode, fun);
2235 /* Look up the tree code for a given rtx code
2236 to provide the arithmetic operation for real_arithmetic.
2237 The function returns an int because the caller may not know
2238 what `enum tree_code' means. */
2241 rtx_to_tree_code (enum rtx_code code)
2243 enum tree_code tcode;
2245 switch (code)
2247 case PLUS:
2248 tcode = PLUS_EXPR;
2249 break;
2250 case MINUS:
2251 tcode = MINUS_EXPR;
2252 break;
2253 case MULT:
2254 tcode = MULT_EXPR;
2255 break;
2256 case DIV:
2257 tcode = RDIV_EXPR;
2258 break;
2259 case SMIN:
2260 tcode = MIN_EXPR;
2261 break;
2262 case SMAX:
2263 tcode = MAX_EXPR;
2264 break;
2265 default:
2266 tcode = LAST_AND_UNUSED_TREE_CODE;
2267 break;
2269 return ((int) tcode);
2272 #include "gt-explow.h"