1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987-2013 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
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.
10
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.
15
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/>. */
19
20
21 #include "config.h"
22 #include "system.h"
23 #include "coretypes.h"
24 #include "tm.h"
25 #include "diagnostic-core.h"
26 #include "rtl.h"
27 #include "tree.h"
28 #include "tm_p.h"
29 #include "flags.h"
30 #include "except.h"
31 #include "function.h"
32 #include "expr.h"
33 #include "optabs.h"
34 #include "libfuncs.h"
35 #include "hard-reg-set.h"
36 #include "insn-config.h"
37 #include "ggc.h"
38 #include "recog.h"
39 #include "langhooks.h"
40 #include "target.h"
41 #include "common/common-target.h"
42 #include "output.h"
43
44 static rtx break_out_memory_refs (rtx);
45
46
47 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
48
49 HOST_WIDE_INT
trunc_int_for_mode(HOST_WIDE_INT c,enum machine_mode mode)50 trunc_int_for_mode (HOST_WIDE_INT c, enum machine_mode mode)
51 {
52 int width = GET_MODE_PRECISION (mode);
53
54 /* You want to truncate to a _what_? */
55 gcc_assert (SCALAR_INT_MODE_P (mode));
56
57 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
58 if (mode == BImode)
59 return c & 1 ? STORE_FLAG_VALUE : 0;
60
61 /* Sign-extend for the requested mode. */
62
63 if (width < HOST_BITS_PER_WIDE_INT)
64 {
65 HOST_WIDE_INT sign = 1;
66 sign <<= width - 1;
67 c &= (sign << 1) - 1;
68 c ^= sign;
69 c -= sign;
70 }
71
72 return c;
73 }
74
75 /* Return an rtx for the sum of X and the integer C, given that X has
76 mode MODE. */
77
78 rtx
plus_constant(enum machine_mode mode,rtx x,HOST_WIDE_INT c)79 plus_constant (enum machine_mode mode, rtx x, HOST_WIDE_INT c)
80 {
81 RTX_CODE code;
82 rtx y;
83 rtx tem;
84 int all_constant = 0;
85
86 gcc_assert (GET_MODE (x) == VOIDmode || GET_MODE (x) == mode);
87
88 if (c == 0)
89 return x;
90
91 restart:
92
93 code = GET_CODE (x);
94 y = x;
95
96 switch (code)
97 {
98 case CONST_INT:
99 if (GET_MODE_BITSIZE (mode) > HOST_BITS_PER_WIDE_INT)
100 {
101 double_int di_x = double_int::from_shwi (INTVAL (x));
102 double_int di_c = double_int::from_shwi (c);
103
104 bool overflow;
105 double_int v = di_x.add_with_sign (di_c, false, &overflow);
106 if (overflow)
107 gcc_unreachable ();
108
109 return immed_double_int_const (v, mode);
110 }
111
112 return gen_int_mode (INTVAL (x) + c, mode);
113
114 case CONST_DOUBLE:
115 {
116 double_int di_x = double_int::from_pair (CONST_DOUBLE_HIGH (x),
117 CONST_DOUBLE_LOW (x));
118 double_int di_c = double_int::from_shwi (c);
119
120 bool overflow;
121 double_int v = di_x.add_with_sign (di_c, false, &overflow);
122 if (overflow)
123 /* Sorry, we have no way to represent overflows this wide.
124 To fix, add constant support wider than CONST_DOUBLE. */
125 gcc_assert (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_DOUBLE_INT);
126
127 return immed_double_int_const (v, mode);
128 }
129
130 case MEM:
131 /* If this is a reference to the constant pool, try replacing it with
132 a reference to a new constant. If the resulting address isn't
133 valid, don't return it because we have no way to validize it. */
134 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
135 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
136 {
137 tem = plus_constant (mode, get_pool_constant (XEXP (x, 0)), c);
138 tem = force_const_mem (GET_MODE (x), tem);
139 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
140 return tem;
141 }
142 break;
143
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 x = XEXP (x, 0);
148 all_constant = 1;
149 goto restart;
150
151 case SYMBOL_REF:
152 case LABEL_REF:
153 all_constant = 1;
154 break;
155
156 case PLUS:
157 /* The interesting case is adding the integer to a sum. Look
158 for constant term in the sum and combine with C. For an
159 integer constant term or a constant term that is not an
160 explicit integer, we combine or group them together anyway.
161
162 We may not immediately return from the recursive call here, lest
163 all_constant gets lost. */
164
165 if (CONSTANT_P (XEXP (x, 1)))
166 {
167 x = gen_rtx_PLUS (mode, XEXP (x, 0),
168 plus_constant (mode, XEXP (x, 1), c));
169 c = 0;
170 }
171 else if (find_constant_term_loc (&y))
172 {
173 /* We need to be careful since X may be shared and we can't
174 modify it in place. */
175 rtx copy = copy_rtx (x);
176 rtx *const_loc = find_constant_term_loc (©);
177
178 *const_loc = plus_constant (mode, *const_loc, c);
179 x = copy;
180 c = 0;
181 }
182 break;
183
184 default:
185 break;
186 }
187
188 if (c != 0)
189 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
190
191 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
192 return x;
193 else if (all_constant)
194 return gen_rtx_CONST (mode, x);
195 else
196 return x;
197 }
198
199 /* If X is a sum, return a new sum like X but lacking any constant terms.
200 Add all the removed constant terms into *CONSTPTR.
201 X itself is not altered. The result != X if and only if
202 it is not isomorphic to X. */
203
204 rtx
eliminate_constant_term(rtx x,rtx * constptr)205 eliminate_constant_term (rtx x, rtx *constptr)
206 {
207 rtx x0, x1;
208 rtx tem;
209
210 if (GET_CODE (x) != PLUS)
211 return x;
212
213 /* First handle constants appearing at this level explicitly. */
214 if (CONST_INT_P (XEXP (x, 1))
215 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
216 XEXP (x, 1)))
217 && CONST_INT_P (tem))
218 {
219 *constptr = tem;
220 return eliminate_constant_term (XEXP (x, 0), constptr);
221 }
222
223 tem = const0_rtx;
224 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
225 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
226 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
227 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
228 *constptr, tem))
229 && CONST_INT_P (tem))
230 {
231 *constptr = tem;
232 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
233 }
234
235 return x;
236 }
237
238 /* Return an rtx for the size in bytes of the value of EXP. */
239
240 rtx
expr_size(tree exp)241 expr_size (tree exp)
242 {
243 tree size;
244
245 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
246 size = TREE_OPERAND (exp, 1);
247 else
248 {
249 size = tree_expr_size (exp);
250 gcc_assert (size);
251 gcc_assert (size == SUBSTITUTE_PLACEHOLDER_IN_EXPR (size, exp));
252 }
253
254 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), EXPAND_NORMAL);
255 }
256
257 /* Return a wide integer for the size in bytes of the value of EXP, or -1
258 if the size can vary or is larger than an integer. */
259
260 HOST_WIDE_INT
int_expr_size(tree exp)261 int_expr_size (tree exp)
262 {
263 tree size;
264
265 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
266 size = TREE_OPERAND (exp, 1);
267 else
268 {
269 size = tree_expr_size (exp);
270 gcc_assert (size);
271 }
272
273 if (size == 0 || !host_integerp (size, 0))
274 return -1;
275
276 return tree_low_cst (size, 0);
277 }
278
279 /* Return a copy of X in which all memory references
280 and all constants that involve symbol refs
281 have been replaced with new temporary registers.
282 Also emit code to load the memory locations and constants
283 into those registers.
284
285 If X contains no such constants or memory references,
286 X itself (not a copy) is returned.
287
288 If a constant is found in the address that is not a legitimate constant
289 in an insn, it is left alone in the hope that it might be valid in the
290 address.
291
292 X may contain no arithmetic except addition, subtraction and multiplication.
293 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
294
295 static rtx
break_out_memory_refs(rtx x)296 break_out_memory_refs (rtx x)
297 {
298 if (MEM_P (x)
299 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
300 && GET_MODE (x) != VOIDmode))
301 x = force_reg (GET_MODE (x), x);
302 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
303 || GET_CODE (x) == MULT)
304 {
305 rtx op0 = break_out_memory_refs (XEXP (x, 0));
306 rtx op1 = break_out_memory_refs (XEXP (x, 1));
307
308 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
309 x = simplify_gen_binary (GET_CODE (x), GET_MODE (x), op0, op1);
310 }
311
312 return x;
313 }
314
315 /* Given X, a memory address in address space AS' pointer mode, convert it to
316 an address in the address space's address mode, or vice versa (TO_MODE says
317 which way). We take advantage of the fact that pointers are not allowed to
318 overflow by commuting arithmetic operations over conversions so that address
319 arithmetic insns can be used. */
320
321 rtx
convert_memory_address_addr_space(enum machine_mode to_mode ATTRIBUTE_UNUSED,rtx x,addr_space_t as ATTRIBUTE_UNUSED)322 convert_memory_address_addr_space (enum machine_mode to_mode ATTRIBUTE_UNUSED,
323 rtx x, addr_space_t as ATTRIBUTE_UNUSED)
324 {
325 #ifndef POINTERS_EXTEND_UNSIGNED
326 gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode);
327 return x;
328 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
329 enum machine_mode pointer_mode, address_mode, from_mode;
330 rtx temp;
331 enum rtx_code code;
332
333 /* If X already has the right mode, just return it. */
334 if (GET_MODE (x) == to_mode)
335 return x;
336
337 pointer_mode = targetm.addr_space.pointer_mode (as);
338 address_mode = targetm.addr_space.address_mode (as);
339 from_mode = to_mode == pointer_mode ? address_mode : pointer_mode;
340
341 /* Here we handle some special cases. If none of them apply, fall through
342 to the default case. */
343 switch (GET_CODE (x))
344 {
345 CASE_CONST_SCALAR_INT:
346 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
347 code = TRUNCATE;
348 else if (POINTERS_EXTEND_UNSIGNED < 0)
349 break;
350 else if (POINTERS_EXTEND_UNSIGNED > 0)
351 code = ZERO_EXTEND;
352 else
353 code = SIGN_EXTEND;
354 temp = simplify_unary_operation (code, to_mode, x, from_mode);
355 if (temp)
356 return temp;
357 break;
358
359 case SUBREG:
360 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
361 && GET_MODE (SUBREG_REG (x)) == to_mode)
362 return SUBREG_REG (x);
363 break;
364
365 case LABEL_REF:
366 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
367 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
368 return temp;
369 break;
370
371 case SYMBOL_REF:
372 temp = shallow_copy_rtx (x);
373 PUT_MODE (temp, to_mode);
374 return temp;
375 break;
376
377 case CONST:
378 return gen_rtx_CONST (to_mode,
379 convert_memory_address_addr_space
380 (to_mode, XEXP (x, 0), as));
381 break;
382
383 case PLUS:
384 case MULT:
385 /* FIXME: For addition, we used to permute the conversion and
386 addition operation only if one operand is a constant and
387 converting the constant does not change it or if one operand
388 is a constant and we are using a ptr_extend instruction
389 (POINTERS_EXTEND_UNSIGNED < 0) even if the resulting address
390 may overflow/underflow. We relax the condition to include
391 zero-extend (POINTERS_EXTEND_UNSIGNED > 0) since the other
392 parts of the compiler depend on it. See PR 49721.
393
394 We can always safely permute them if we are making the address
395 narrower. */
396 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
397 || (GET_CODE (x) == PLUS
398 && CONST_INT_P (XEXP (x, 1))
399 && (POINTERS_EXTEND_UNSIGNED != 0
400 || XEXP (x, 1) == convert_memory_address_addr_space
401 (to_mode, XEXP (x, 1), as))))
402 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
403 convert_memory_address_addr_space
404 (to_mode, XEXP (x, 0), as),
405 XEXP (x, 1));
406 break;
407
408 default:
409 break;
410 }
411
412 return convert_modes (to_mode, from_mode,
413 x, POINTERS_EXTEND_UNSIGNED);
414 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
415 }
416
417 /* Return something equivalent to X but valid as a memory address for something
418 of mode MODE in the named address space AS. When X is not itself valid,
419 this works by copying X or subexpressions of it into registers. */
420
421 rtx
memory_address_addr_space(enum machine_mode mode,rtx x,addr_space_t as)422 memory_address_addr_space (enum machine_mode mode, rtx x, addr_space_t as)
423 {
424 rtx oldx = x;
425 enum machine_mode address_mode = targetm.addr_space.address_mode (as);
426
427 x = convert_memory_address_addr_space (address_mode, x, as);
428
429 /* By passing constant addresses through registers
430 we get a chance to cse them. */
431 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
432 x = force_reg (address_mode, x);
433
434 /* We get better cse by rejecting indirect addressing at this stage.
435 Let the combiner create indirect addresses where appropriate.
436 For now, generate the code so that the subexpressions useful to share
437 are visible. But not if cse won't be done! */
438 else
439 {
440 if (! cse_not_expected && !REG_P (x))
441 x = break_out_memory_refs (x);
442
443 /* At this point, any valid address is accepted. */
444 if (memory_address_addr_space_p (mode, x, as))
445 goto done;
446
447 /* If it was valid before but breaking out memory refs invalidated it,
448 use it the old way. */
449 if (memory_address_addr_space_p (mode, oldx, as))
450 {
451 x = oldx;
452 goto done;
453 }
454
455 /* Perform machine-dependent transformations on X
456 in certain cases. This is not necessary since the code
457 below can handle all possible cases, but machine-dependent
458 transformations can make better code. */
459 {
460 rtx orig_x = x;
461 x = targetm.addr_space.legitimize_address (x, oldx, mode, as);
462 if (orig_x != x && memory_address_addr_space_p (mode, x, as))
463 goto done;
464 }
465
466 /* PLUS and MULT can appear in special ways
467 as the result of attempts to make an address usable for indexing.
468 Usually they are dealt with by calling force_operand, below.
469 But a sum containing constant terms is special
470 if removing them makes the sum a valid address:
471 then we generate that address in a register
472 and index off of it. We do this because it often makes
473 shorter code, and because the addresses thus generated
474 in registers often become common subexpressions. */
475 if (GET_CODE (x) == PLUS)
476 {
477 rtx constant_term = const0_rtx;
478 rtx y = eliminate_constant_term (x, &constant_term);
479 if (constant_term == const0_rtx
480 || ! memory_address_addr_space_p (mode, y, as))
481 x = force_operand (x, NULL_RTX);
482 else
483 {
484 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
485 if (! memory_address_addr_space_p (mode, y, as))
486 x = force_operand (x, NULL_RTX);
487 else
488 x = y;
489 }
490 }
491
492 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
493 x = force_operand (x, NULL_RTX);
494
495 /* If we have a register that's an invalid address,
496 it must be a hard reg of the wrong class. Copy it to a pseudo. */
497 else if (REG_P (x))
498 x = copy_to_reg (x);
499
500 /* Last resort: copy the value to a register, since
501 the register is a valid address. */
502 else
503 x = force_reg (address_mode, x);
504 }
505
506 done:
507
508 gcc_assert (memory_address_addr_space_p (mode, x, as));
509 /* If we didn't change the address, we are done. Otherwise, mark
510 a reg as a pointer if we have REG or REG + CONST_INT. */
511 if (oldx == x)
512 return x;
513 else if (REG_P (x))
514 mark_reg_pointer (x, BITS_PER_UNIT);
515 else if (GET_CODE (x) == PLUS
516 && REG_P (XEXP (x, 0))
517 && CONST_INT_P (XEXP (x, 1)))
518 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
519
520 /* OLDX may have been the address on a temporary. Update the address
521 to indicate that X is now used. */
522 update_temp_slot_address (oldx, x);
523
524 return x;
525 }
526
527 /* Convert a mem ref into one with a valid memory address.
528 Pass through anything else unchanged. */
529
530 rtx
validize_mem(rtx ref)531 validize_mem (rtx ref)
532 {
533 if (!MEM_P (ref))
534 return ref;
535 ref = use_anchored_address (ref);
536 if (memory_address_addr_space_p (GET_MODE (ref), XEXP (ref, 0),
537 MEM_ADDR_SPACE (ref)))
538 return ref;
539
540 /* Don't alter REF itself, since that is probably a stack slot. */
541 return replace_equiv_address (ref, XEXP (ref, 0));
542 }
543
544 /* If X is a memory reference to a member of an object block, try rewriting
545 it to use an anchor instead. Return the new memory reference on success
546 and the old one on failure. */
547
548 rtx
use_anchored_address(rtx x)549 use_anchored_address (rtx x)
550 {
551 rtx base;
552 HOST_WIDE_INT offset;
553 enum machine_mode mode;
554
555 if (!flag_section_anchors)
556 return x;
557
558 if (!MEM_P (x))
559 return x;
560
561 /* Split the address into a base and offset. */
562 base = XEXP (x, 0);
563 offset = 0;
564 if (GET_CODE (base) == CONST
565 && GET_CODE (XEXP (base, 0)) == PLUS
566 && CONST_INT_P (XEXP (XEXP (base, 0), 1)))
567 {
568 offset += INTVAL (XEXP (XEXP (base, 0), 1));
569 base = XEXP (XEXP (base, 0), 0);
570 }
571
572 /* Check whether BASE is suitable for anchors. */
573 if (GET_CODE (base) != SYMBOL_REF
574 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base)
575 || SYMBOL_REF_ANCHOR_P (base)
576 || SYMBOL_REF_BLOCK (base) == NULL
577 || !targetm.use_anchors_for_symbol_p (base))
578 return x;
579
580 /* Decide where BASE is going to be. */
581 place_block_symbol (base);
582
583 /* Get the anchor we need to use. */
584 offset += SYMBOL_REF_BLOCK_OFFSET (base);
585 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset,
586 SYMBOL_REF_TLS_MODEL (base));
587
588 /* Work out the offset from the anchor. */
589 offset -= SYMBOL_REF_BLOCK_OFFSET (base);
590
591 /* If we're going to run a CSE pass, force the anchor into a register.
592 We will then be able to reuse registers for several accesses, if the
593 target costs say that that's worthwhile. */
594 mode = GET_MODE (base);
595 if (!cse_not_expected)
596 base = force_reg (mode, base);
597
598 return replace_equiv_address (x, plus_constant (mode, base, offset));
599 }
600
601 /* Copy the value or contents of X to a new temp reg and return that reg. */
602
603 rtx
copy_to_reg(rtx x)604 copy_to_reg (rtx x)
605 {
606 rtx temp = gen_reg_rtx (GET_MODE (x));
607
608 /* If not an operand, must be an address with PLUS and MULT so
609 do the computation. */
610 if (! general_operand (x, VOIDmode))
611 x = force_operand (x, temp);
612
613 if (x != temp)
614 emit_move_insn (temp, x);
615
616 return temp;
617 }
618
619 /* Like copy_to_reg but always give the new register mode Pmode
620 in case X is a constant. */
621
622 rtx
copy_addr_to_reg(rtx x)623 copy_addr_to_reg (rtx x)
624 {
625 return copy_to_mode_reg (Pmode, x);
626 }
627
628 /* Like copy_to_reg but always give the new register mode MODE
629 in case X is a constant. */
630
631 rtx
copy_to_mode_reg(enum machine_mode mode,rtx x)632 copy_to_mode_reg (enum machine_mode mode, rtx x)
633 {
634 rtx temp = gen_reg_rtx (mode);
635
636 /* If not an operand, must be an address with PLUS and MULT so
637 do the computation. */
638 if (! general_operand (x, VOIDmode))
639 x = force_operand (x, temp);
640
641 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
642 if (x != temp)
643 emit_move_insn (temp, x);
644 return temp;
645 }
646
647 /* Load X into a register if it is not already one.
648 Use mode MODE for the register.
649 X should be valid for mode MODE, but it may be a constant which
650 is valid for all integer modes; that's why caller must specify MODE.
651
652 The caller must not alter the value in the register we return,
653 since we mark it as a "constant" register. */
654
655 rtx
force_reg(enum machine_mode mode,rtx x)656 force_reg (enum machine_mode mode, rtx x)
657 {
658 rtx temp, insn, set;
659
660 if (REG_P (x))
661 return x;
662
663 if (general_operand (x, mode))
664 {
665 temp = gen_reg_rtx (mode);
666 insn = emit_move_insn (temp, x);
667 }
668 else
669 {
670 temp = force_operand (x, NULL_RTX);
671 if (REG_P (temp))
672 insn = get_last_insn ();
673 else
674 {
675 rtx temp2 = gen_reg_rtx (mode);
676 insn = emit_move_insn (temp2, temp);
677 temp = temp2;
678 }
679 }
680
681 /* Let optimizers know that TEMP's value never changes
682 and that X can be substituted for it. Don't get confused
683 if INSN set something else (such as a SUBREG of TEMP). */
684 if (CONSTANT_P (x)
685 && (set = single_set (insn)) != 0
686 && SET_DEST (set) == temp
687 && ! rtx_equal_p (x, SET_SRC (set)))
688 set_unique_reg_note (insn, REG_EQUAL, x);
689
690 /* Let optimizers know that TEMP is a pointer, and if so, the
691 known alignment of that pointer. */
692 {
693 unsigned align = 0;
694 if (GET_CODE (x) == SYMBOL_REF)
695 {
696 align = BITS_PER_UNIT;
697 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
698 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
699 }
700 else if (GET_CODE (x) == LABEL_REF)
701 align = BITS_PER_UNIT;
702 else if (GET_CODE (x) == CONST
703 && GET_CODE (XEXP (x, 0)) == PLUS
704 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
705 && CONST_INT_P (XEXP (XEXP (x, 0), 1)))
706 {
707 rtx s = XEXP (XEXP (x, 0), 0);
708 rtx c = XEXP (XEXP (x, 0), 1);
709 unsigned sa, ca;
710
711 sa = BITS_PER_UNIT;
712 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
713 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
714
715 if (INTVAL (c) == 0)
716 align = sa;
717 else
718 {
719 ca = ctz_hwi (INTVAL (c)) * BITS_PER_UNIT;
720 align = MIN (sa, ca);
721 }
722 }
723
724 if (align || (MEM_P (x) && MEM_POINTER (x)))
725 mark_reg_pointer (temp, align);
726 }
727
728 return temp;
729 }
730
731 /* If X is a memory ref, copy its contents to a new temp reg and return
732 that reg. Otherwise, return X. */
733
734 rtx
force_not_mem(rtx x)735 force_not_mem (rtx x)
736 {
737 rtx temp;
738
739 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
740 return x;
741
742 temp = gen_reg_rtx (GET_MODE (x));
743
744 if (MEM_POINTER (x))
745 REG_POINTER (temp) = 1;
746
747 emit_move_insn (temp, x);
748 return temp;
749 }
750
751 /* Copy X to TARGET (if it's nonzero and a reg)
752 or to a new temp reg and return that reg.
753 MODE is the mode to use for X in case it is a constant. */
754
755 rtx
copy_to_suggested_reg(rtx x,rtx target,enum machine_mode mode)756 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode)
757 {
758 rtx temp;
759
760 if (target && REG_P (target))
761 temp = target;
762 else
763 temp = gen_reg_rtx (mode);
764
765 emit_move_insn (temp, x);
766 return temp;
767 }
768
769 /* Return the mode to use to pass or return a scalar of TYPE and MODE.
770 PUNSIGNEDP points to the signedness of the type and may be adjusted
771 to show what signedness to use on extension operations.
772
773 FOR_RETURN is nonzero if the caller is promoting the return value
774 of FNDECL, else it is for promoting args. */
775
776 enum machine_mode
promote_function_mode(const_tree type,enum machine_mode mode,int * punsignedp,const_tree funtype,int for_return)777 promote_function_mode (const_tree type, enum machine_mode mode, int *punsignedp,
778 const_tree funtype, int for_return)
779 {
780 /* Called without a type node for a libcall. */
781 if (type == NULL_TREE)
782 {
783 if (INTEGRAL_MODE_P (mode))
784 return targetm.calls.promote_function_mode (NULL_TREE, mode,
785 punsignedp, funtype,
786 for_return);
787 else
788 return mode;
789 }
790
791 switch (TREE_CODE (type))
792 {
793 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
794 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
795 case POINTER_TYPE: case REFERENCE_TYPE:
796 return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype,
797 for_return);
798
799 default:
800 return mode;
801 }
802 }
803 /* Return the mode to use to store a scalar of TYPE and MODE.
804 PUNSIGNEDP points to the signedness of the type and may be adjusted
805 to show what signedness to use on extension operations. */
806
807 enum machine_mode
promote_mode(const_tree type ATTRIBUTE_UNUSED,enum machine_mode mode,int * punsignedp ATTRIBUTE_UNUSED)808 promote_mode (const_tree type ATTRIBUTE_UNUSED, enum machine_mode mode,
809 int *punsignedp ATTRIBUTE_UNUSED)
810 {
811 #ifdef PROMOTE_MODE
812 enum tree_code code;
813 int unsignedp;
814 #endif
815
816 /* For libcalls this is invoked without TYPE from the backends
817 TARGET_PROMOTE_FUNCTION_MODE hooks. Don't do anything in that
818 case. */
819 if (type == NULL_TREE)
820 return mode;
821
822 /* FIXME: this is the same logic that was there until GCC 4.4, but we
823 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
824 is not defined. The affected targets are M32C, S390, SPARC. */
825 #ifdef PROMOTE_MODE
826 code = TREE_CODE (type);
827 unsignedp = *punsignedp;
828
829 switch (code)
830 {
831 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
832 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
833 PROMOTE_MODE (mode, unsignedp, type);
834 *punsignedp = unsignedp;
835 return mode;
836 break;
837
838 #ifdef POINTERS_EXTEND_UNSIGNED
839 case REFERENCE_TYPE:
840 case POINTER_TYPE:
841 *punsignedp = POINTERS_EXTEND_UNSIGNED;
842 return targetm.addr_space.address_mode
843 (TYPE_ADDR_SPACE (TREE_TYPE (type)));
844 break;
845 #endif
846
847 default:
848 return mode;
849 }
850 #else
851 return mode;
852 #endif
853 }
854
855
856 /* Use one of promote_mode or promote_function_mode to find the promoted
857 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
858 of DECL after promotion. */
859
860 enum machine_mode
promote_decl_mode(const_tree decl,int * punsignedp)861 promote_decl_mode (const_tree decl, int *punsignedp)
862 {
863 tree type = TREE_TYPE (decl);
864 int unsignedp = TYPE_UNSIGNED (type);
865 enum machine_mode mode = DECL_MODE (decl);
866 enum machine_mode pmode;
867
868 if (TREE_CODE (decl) == RESULT_DECL
869 || TREE_CODE (decl) == PARM_DECL)
870 pmode = promote_function_mode (type, mode, &unsignedp,
871 TREE_TYPE (current_function_decl), 2);
872 else
873 pmode = promote_mode (type, mode, &unsignedp);
874
875 if (punsignedp)
876 *punsignedp = unsignedp;
877 return pmode;
878 }
879
880
881 /* Controls the behaviour of {anti_,}adjust_stack. */
882 static bool suppress_reg_args_size;
883
884 /* A helper for adjust_stack and anti_adjust_stack. */
885
886 static void
adjust_stack_1(rtx adjust,bool anti_p)887 adjust_stack_1 (rtx adjust, bool anti_p)
888 {
889 rtx temp, insn;
890
891 #ifndef STACK_GROWS_DOWNWARD
892 /* Hereafter anti_p means subtract_p. */
893 anti_p = !anti_p;
894 #endif
895
896 temp = expand_binop (Pmode,
897 anti_p ? sub_optab : add_optab,
898 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
899 OPTAB_LIB_WIDEN);
900
901 if (temp != stack_pointer_rtx)
902 insn = emit_move_insn (stack_pointer_rtx, temp);
903 else
904 {
905 insn = get_last_insn ();
906 temp = single_set (insn);
907 gcc_assert (temp != NULL && SET_DEST (temp) == stack_pointer_rtx);
908 }
909
910 if (!suppress_reg_args_size)
911 add_reg_note (insn, REG_ARGS_SIZE, GEN_INT (stack_pointer_delta));
912 }
913
914 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
915 This pops when ADJUST is positive. ADJUST need not be constant. */
916
917 void
adjust_stack(rtx adjust)918 adjust_stack (rtx adjust)
919 {
920 if (adjust == const0_rtx)
921 return;
922
923 /* We expect all variable sized adjustments to be multiple of
924 PREFERRED_STACK_BOUNDARY. */
925 if (CONST_INT_P (adjust))
926 stack_pointer_delta -= INTVAL (adjust);
927
928 adjust_stack_1 (adjust, false);
929 }
930
931 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
932 This pushes when ADJUST is positive. ADJUST need not be constant. */
933
934 void
anti_adjust_stack(rtx adjust)935 anti_adjust_stack (rtx adjust)
936 {
937 if (adjust == const0_rtx)
938 return;
939
940 /* We expect all variable sized adjustments to be multiple of
941 PREFERRED_STACK_BOUNDARY. */
942 if (CONST_INT_P (adjust))
943 stack_pointer_delta += INTVAL (adjust);
944
945 adjust_stack_1 (adjust, true);
946 }
947
948 /* Round the size of a block to be pushed up to the boundary required
949 by this machine. SIZE is the desired size, which need not be constant. */
950
951 static rtx
round_push(rtx size)952 round_push (rtx size)
953 {
954 rtx align_rtx, alignm1_rtx;
955
956 if (!SUPPORTS_STACK_ALIGNMENT
957 || crtl->preferred_stack_boundary == MAX_SUPPORTED_STACK_ALIGNMENT)
958 {
959 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
960
961 if (align == 1)
962 return size;
963
964 if (CONST_INT_P (size))
965 {
966 HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
967
968 if (INTVAL (size) != new_size)
969 size = GEN_INT (new_size);
970 return size;
971 }
972
973 align_rtx = GEN_INT (align);
974 alignm1_rtx = GEN_INT (align - 1);
975 }
976 else
977 {
978 /* If crtl->preferred_stack_boundary might still grow, use
979 virtual_preferred_stack_boundary_rtx instead. This will be
980 substituted by the right value in vregs pass and optimized
981 during combine. */
982 align_rtx = virtual_preferred_stack_boundary_rtx;
983 alignm1_rtx = force_operand (plus_constant (Pmode, align_rtx, -1),
984 NULL_RTX);
985 }
986
987 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
988 but we know it can't. So add ourselves and then do
989 TRUNC_DIV_EXPR. */
990 size = expand_binop (Pmode, add_optab, size, alignm1_rtx,
991 NULL_RTX, 1, OPTAB_LIB_WIDEN);
992 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, align_rtx,
993 NULL_RTX, 1);
994 size = expand_mult (Pmode, size, align_rtx, NULL_RTX, 1);
995
996 return size;
997 }
998
999 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
1000 to a previously-created save area. If no save area has been allocated,
1001 this function will allocate one. If a save area is specified, it
1002 must be of the proper mode. */
1003
1004 void
emit_stack_save(enum save_level save_level,rtx * psave)1005 emit_stack_save (enum save_level save_level, rtx *psave)
1006 {
1007 rtx sa = *psave;
1008 /* The default is that we use a move insn and save in a Pmode object. */
1009 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1010 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
1011
1012 /* See if this machine has anything special to do for this kind of save. */
1013 switch (save_level)
1014 {
1015 #ifdef HAVE_save_stack_block
1016 case SAVE_BLOCK:
1017 if (HAVE_save_stack_block)
1018 fcn = gen_save_stack_block;
1019 break;
1020 #endif
1021 #ifdef HAVE_save_stack_function
1022 case SAVE_FUNCTION:
1023 if (HAVE_save_stack_function)
1024 fcn = gen_save_stack_function;
1025 break;
1026 #endif
1027 #ifdef HAVE_save_stack_nonlocal
1028 case SAVE_NONLOCAL:
1029 if (HAVE_save_stack_nonlocal)
1030 fcn = gen_save_stack_nonlocal;
1031 break;
1032 #endif
1033 default:
1034 break;
1035 }
1036
1037 /* If there is no save area and we have to allocate one, do so. Otherwise
1038 verify the save area is the proper mode. */
1039
1040 if (sa == 0)
1041 {
1042 if (mode != VOIDmode)
1043 {
1044 if (save_level == SAVE_NONLOCAL)
1045 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
1046 else
1047 *psave = sa = gen_reg_rtx (mode);
1048 }
1049 }
1050
1051 do_pending_stack_adjust ();
1052 if (sa != 0)
1053 sa = validize_mem (sa);
1054 emit_insn (fcn (sa, stack_pointer_rtx));
1055 }
1056
1057 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1058 area made by emit_stack_save. If it is zero, we have nothing to do. */
1059
1060 void
emit_stack_restore(enum save_level save_level,rtx sa)1061 emit_stack_restore (enum save_level save_level, rtx sa)
1062 {
1063 /* The default is that we use a move insn. */
1064 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1065
1066 /* If stack_realign_drap, the x86 backend emits a prologue that aligns both
1067 STACK_POINTER and HARD_FRAME_POINTER.
1068 If stack_realign_fp, the x86 backend emits a prologue that aligns only
1069 STACK_POINTER. This renders the HARD_FRAME_POINTER unusable for accessing
1070 aligned variables, which is reflected in ix86_can_eliminate.
1071 We normally still have the realigned STACK_POINTER that we can use.
1072 But if there is a stack restore still present at reload, it can trigger
1073 mark_not_eliminable for the STACK_POINTER, leaving no way to eliminate
1074 FRAME_POINTER into a hard reg.
1075 To prevent this situation, we force need_drap if we emit a stack
1076 restore. */
1077 if (SUPPORTS_STACK_ALIGNMENT)
1078 crtl->need_drap = true;
1079
1080 /* See if this machine has anything special to do for this kind of save. */
1081 switch (save_level)
1082 {
1083 #ifdef HAVE_restore_stack_block
1084 case SAVE_BLOCK:
1085 if (HAVE_restore_stack_block)
1086 fcn = gen_restore_stack_block;
1087 break;
1088 #endif
1089 #ifdef HAVE_restore_stack_function
1090 case SAVE_FUNCTION:
1091 if (HAVE_restore_stack_function)
1092 fcn = gen_restore_stack_function;
1093 break;
1094 #endif
1095 #ifdef HAVE_restore_stack_nonlocal
1096 case SAVE_NONLOCAL:
1097 if (HAVE_restore_stack_nonlocal)
1098 fcn = gen_restore_stack_nonlocal;
1099 break;
1100 #endif
1101 default:
1102 break;
1103 }
1104
1105 if (sa != 0)
1106 {
1107 sa = validize_mem (sa);
1108 /* These clobbers prevent the scheduler from moving
1109 references to variable arrays below the code
1110 that deletes (pops) the arrays. */
1111 emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
1112 emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx));
1113 }
1114
1115 discard_pending_stack_adjust ();
1116
1117 emit_insn (fcn (stack_pointer_rtx, sa));
1118 }
1119
1120 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1121 function. This function should be called whenever we allocate or
1122 deallocate dynamic stack space. */
1123
1124 void
update_nonlocal_goto_save_area(void)1125 update_nonlocal_goto_save_area (void)
1126 {
1127 tree t_save;
1128 rtx r_save;
1129
1130 /* The nonlocal_goto_save_area object is an array of N pointers. The
1131 first one is used for the frame pointer save; the rest are sized by
1132 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1133 of the stack save area slots. */
1134 t_save = build4 (ARRAY_REF,
1135 TREE_TYPE (TREE_TYPE (cfun->nonlocal_goto_save_area)),
1136 cfun->nonlocal_goto_save_area,
1137 integer_one_node, NULL_TREE, NULL_TREE);
1138 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1139
1140 emit_stack_save (SAVE_NONLOCAL, &r_save);
1141 }
1142
1143 /* Return an rtx representing the address of an area of memory dynamically
1144 pushed on the stack.
1145
1146 Any required stack pointer alignment is preserved.
1147
1148 SIZE is an rtx representing the size of the area.
1149
1150 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1151 parameter may be zero. If so, a proper value will be extracted
1152 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1153
1154 REQUIRED_ALIGN is the alignment (in bits) required for the region
1155 of memory.
1156
1157 If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
1158 stack space allocated by the generated code cannot be added with itself
1159 in the course of the execution of the function. It is always safe to
1160 pass FALSE here and the following criterion is sufficient in order to
1161 pass TRUE: every path in the CFG that starts at the allocation point and
1162 loops to it executes the associated deallocation code. */
1163
1164 rtx
allocate_dynamic_stack_space(rtx size,unsigned size_align,unsigned required_align,bool cannot_accumulate)1165 allocate_dynamic_stack_space (rtx size, unsigned size_align,
1166 unsigned required_align, bool cannot_accumulate)
1167 {
1168 HOST_WIDE_INT stack_usage_size = -1;
1169 rtx final_label, final_target, target;
1170 unsigned extra_align = 0;
1171 bool must_align;
1172
1173 /* If we're asking for zero bytes, it doesn't matter what we point
1174 to since we can't dereference it. But return a reasonable
1175 address anyway. */
1176 if (size == const0_rtx)
1177 return virtual_stack_dynamic_rtx;
1178
1179 /* Otherwise, show we're calling alloca or equivalent. */
1180 cfun->calls_alloca = 1;
1181
1182 /* If stack usage info is requested, look into the size we are passed.
1183 We need to do so this early to avoid the obfuscation that may be
1184 introduced later by the various alignment operations. */
1185 if (flag_stack_usage_info)
1186 {
1187 if (CONST_INT_P (size))
1188 stack_usage_size = INTVAL (size);
1189 else if (REG_P (size))
1190 {
1191 /* Look into the last emitted insn and see if we can deduce
1192 something for the register. */
1193 rtx insn, set, note;
1194 insn = get_last_insn ();
1195 if ((set = single_set (insn)) && rtx_equal_p (SET_DEST (set), size))
1196 {
1197 if (CONST_INT_P (SET_SRC (set)))
1198 stack_usage_size = INTVAL (SET_SRC (set));
1199 else if ((note = find_reg_equal_equiv_note (insn))
1200 && CONST_INT_P (XEXP (note, 0)))
1201 stack_usage_size = INTVAL (XEXP (note, 0));
1202 }
1203 }
1204
1205 /* If the size is not constant, we can't say anything. */
1206 if (stack_usage_size == -1)
1207 {
1208 current_function_has_unbounded_dynamic_stack_size = 1;
1209 stack_usage_size = 0;
1210 }
1211 }
1212
1213 /* Ensure the size is in the proper mode. */
1214 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1215 size = convert_to_mode (Pmode, size, 1);
1216
1217 /* Adjust SIZE_ALIGN, if needed. */
1218 if (CONST_INT_P (size))
1219 {
1220 unsigned HOST_WIDE_INT lsb;
1221
1222 lsb = INTVAL (size);
1223 lsb &= -lsb;
1224
1225 /* Watch out for overflow truncating to "unsigned". */
1226 if (lsb > UINT_MAX / BITS_PER_UNIT)
1227 size_align = 1u << (HOST_BITS_PER_INT - 1);
1228 else
1229 size_align = (unsigned)lsb * BITS_PER_UNIT;
1230 }
1231 else if (size_align < BITS_PER_UNIT)
1232 size_align = BITS_PER_UNIT;
1233
1234 /* We can't attempt to minimize alignment necessary, because we don't
1235 know the final value of preferred_stack_boundary yet while executing
1236 this code. */
1237 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
1238 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1239
1240 /* We will need to ensure that the address we return is aligned to
1241 REQUIRED_ALIGN. If STACK_DYNAMIC_OFFSET is defined, we don't
1242 always know its final value at this point in the compilation (it
1243 might depend on the size of the outgoing parameter lists, for
1244 example), so we must align the value to be returned in that case.
1245 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1246 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1247 We must also do an alignment operation on the returned value if
1248 the stack pointer alignment is less strict than REQUIRED_ALIGN.
1249
1250 If we have to align, we must leave space in SIZE for the hole
1251 that might result from the alignment operation. */
1252
1253 must_align = (crtl->preferred_stack_boundary < required_align);
1254 if (must_align)
1255 {
1256 if (required_align > PREFERRED_STACK_BOUNDARY)
1257 extra_align = PREFERRED_STACK_BOUNDARY;
1258 else if (required_align > STACK_BOUNDARY)
1259 extra_align = STACK_BOUNDARY;
1260 else
1261 extra_align = BITS_PER_UNIT;
1262 }
1263
1264 /* ??? STACK_POINTER_OFFSET is always defined now. */
1265 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1266 must_align = true;
1267 extra_align = BITS_PER_UNIT;
1268 #endif
1269
1270 if (must_align)
1271 {
1272 unsigned extra = (required_align - extra_align) / BITS_PER_UNIT;
1273
1274 size = plus_constant (Pmode, size, extra);
1275 size = force_operand (size, NULL_RTX);
1276
1277 if (flag_stack_usage_info)
1278 stack_usage_size += extra;
1279
1280 if (extra && size_align > extra_align)
1281 size_align = extra_align;
1282 }
1283
1284 /* Round the size to a multiple of the required stack alignment.
1285 Since the stack if presumed to be rounded before this allocation,
1286 this will maintain the required alignment.
1287
1288 If the stack grows downward, we could save an insn by subtracting
1289 SIZE from the stack pointer and then aligning the stack pointer.
1290 The problem with this is that the stack pointer may be unaligned
1291 between the execution of the subtraction and alignment insns and
1292 some machines do not allow this. Even on those that do, some
1293 signal handlers malfunction if a signal should occur between those
1294 insns. Since this is an extremely rare event, we have no reliable
1295 way of knowing which systems have this problem. So we avoid even
1296 momentarily mis-aligning the stack. */
1297 if (size_align % MAX_SUPPORTED_STACK_ALIGNMENT != 0)
1298 {
1299 size = round_push (size);
1300
1301 if (flag_stack_usage_info)
1302 {
1303 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
1304 stack_usage_size = (stack_usage_size + align - 1) / align * align;
1305 }
1306 }
1307
1308 target = gen_reg_rtx (Pmode);
1309
1310 /* The size is supposed to be fully adjusted at this point so record it
1311 if stack usage info is requested. */
1312 if (flag_stack_usage_info)
1313 {
1314 current_function_dynamic_stack_size += stack_usage_size;
1315
1316 /* ??? This is gross but the only safe stance in the absence
1317 of stack usage oriented flow analysis. */
1318 if (!cannot_accumulate)
1319 current_function_has_unbounded_dynamic_stack_size = 1;
1320 }
1321
1322 final_label = NULL_RTX;
1323 final_target = NULL_RTX;
1324
1325 /* If we are splitting the stack, we need to ask the backend whether
1326 there is enough room on the current stack. If there isn't, or if
1327 the backend doesn't know how to tell is, then we need to call a
1328 function to allocate memory in some other way. This memory will
1329 be released when we release the current stack segment. The
1330 effect is that stack allocation becomes less efficient, but at
1331 least it doesn't cause a stack overflow. */
1332 if (flag_split_stack)
1333 {
1334 rtx available_label, ask, space, func;
1335
1336 available_label = NULL_RTX;
1337
1338 #ifdef HAVE_split_stack_space_check
1339 if (HAVE_split_stack_space_check)
1340 {
1341 available_label = gen_label_rtx ();
1342
1343 /* This instruction will branch to AVAILABLE_LABEL if there
1344 are SIZE bytes available on the stack. */
1345 emit_insn (gen_split_stack_space_check (size, available_label));
1346 }
1347 #endif
1348
1349 /* The __morestack_allocate_stack_space function will allocate
1350 memory using malloc. If the alignment of the memory returned
1351 by malloc does not meet REQUIRED_ALIGN, we increase SIZE to
1352 make sure we allocate enough space. */
1353 if (MALLOC_ABI_ALIGNMENT >= required_align)
1354 ask = size;
1355 else
1356 {
1357 ask = expand_binop (Pmode, add_optab, size,
1358 GEN_INT (required_align / BITS_PER_UNIT - 1),
1359 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1360 must_align = true;
1361 }
1362
1363 func = init_one_libfunc ("__morestack_allocate_stack_space");
1364
1365 space = emit_library_call_value (func, target, LCT_NORMAL, Pmode,
1366 1, ask, Pmode);
1367
1368 if (available_label == NULL_RTX)
1369 return space;
1370
1371 final_target = gen_reg_rtx (Pmode);
1372
1373 emit_move_insn (final_target, space);
1374
1375 final_label = gen_label_rtx ();
1376 emit_jump (final_label);
1377
1378 emit_label (available_label);
1379 }
1380
1381 do_pending_stack_adjust ();
1382
1383 /* We ought to be called always on the toplevel and stack ought to be aligned
1384 properly. */
1385 gcc_assert (!(stack_pointer_delta
1386 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)));
1387
1388 /* If needed, check that we have the required amount of stack. Take into
1389 account what has already been checked. */
1390 if (STACK_CHECK_MOVING_SP)
1391 ;
1392 else if (flag_stack_check == GENERIC_STACK_CHECK)
1393 probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE,
1394 size);
1395 else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
1396 probe_stack_range (STACK_CHECK_PROTECT, size);
1397
1398 /* Don't let anti_adjust_stack emit notes. */
1399 suppress_reg_args_size = true;
1400
1401 /* Perform the required allocation from the stack. Some systems do
1402 this differently than simply incrementing/decrementing from the
1403 stack pointer, such as acquiring the space by calling malloc(). */
1404 #ifdef HAVE_allocate_stack
1405 if (HAVE_allocate_stack)
1406 {
1407 struct expand_operand ops[2];
1408 /* We don't have to check against the predicate for operand 0 since
1409 TARGET is known to be a pseudo of the proper mode, which must
1410 be valid for the operand. */
1411 create_fixed_operand (&ops[0], target);
1412 create_convert_operand_to (&ops[1], size, STACK_SIZE_MODE, true);
1413 expand_insn (CODE_FOR_allocate_stack, 2, ops);
1414 }
1415 else
1416 #endif
1417 {
1418 int saved_stack_pointer_delta;
1419
1420 #ifndef STACK_GROWS_DOWNWARD
1421 emit_move_insn (target, virtual_stack_dynamic_rtx);
1422 #endif
1423
1424 /* Check stack bounds if necessary. */
1425 if (crtl->limit_stack)
1426 {
1427 rtx available;
1428 rtx space_available = gen_label_rtx ();
1429 #ifdef STACK_GROWS_DOWNWARD
1430 available = expand_binop (Pmode, sub_optab,
1431 stack_pointer_rtx, stack_limit_rtx,
1432 NULL_RTX, 1, OPTAB_WIDEN);
1433 #else
1434 available = expand_binop (Pmode, sub_optab,
1435 stack_limit_rtx, stack_pointer_rtx,
1436 NULL_RTX, 1, OPTAB_WIDEN);
1437 #endif
1438 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1439 space_available);
1440 #ifdef HAVE_trap
1441 if (HAVE_trap)
1442 emit_insn (gen_trap ());
1443 else
1444 #endif
1445 error ("stack limits not supported on this target");
1446 emit_barrier ();
1447 emit_label (space_available);
1448 }
1449
1450 saved_stack_pointer_delta = stack_pointer_delta;
1451
1452 if (flag_stack_check && STACK_CHECK_MOVING_SP)
1453 anti_adjust_stack_and_probe (size, false);
1454 else
1455 anti_adjust_stack (size);
1456
1457 /* Even if size is constant, don't modify stack_pointer_delta.
1458 The constant size alloca should preserve
1459 crtl->preferred_stack_boundary alignment. */
1460 stack_pointer_delta = saved_stack_pointer_delta;
1461
1462 #ifdef STACK_GROWS_DOWNWARD
1463 emit_move_insn (target, virtual_stack_dynamic_rtx);
1464 #endif
1465 }
1466
1467 suppress_reg_args_size = false;
1468
1469 /* Finish up the split stack handling. */
1470 if (final_label != NULL_RTX)
1471 {
1472 gcc_assert (flag_split_stack);
1473 emit_move_insn (final_target, target);
1474 emit_label (final_label);
1475 target = final_target;
1476 }
1477
1478 if (must_align)
1479 {
1480 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1481 but we know it can't. So add ourselves and then do
1482 TRUNC_DIV_EXPR. */
1483 target = expand_binop (Pmode, add_optab, target,
1484 GEN_INT (required_align / BITS_PER_UNIT - 1),
1485 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1486 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1487 GEN_INT (required_align / BITS_PER_UNIT),
1488 NULL_RTX, 1);
1489 target = expand_mult (Pmode, target,
1490 GEN_INT (required_align / BITS_PER_UNIT),
1491 NULL_RTX, 1);
1492 }
1493
1494 /* Now that we've committed to a return value, mark its alignment. */
1495 mark_reg_pointer (target, required_align);
1496
1497 /* Record the new stack level for nonlocal gotos. */
1498 if (cfun->nonlocal_goto_save_area != 0)
1499 update_nonlocal_goto_save_area ();
1500
1501 return target;
1502 }
1503
1504 /* A front end may want to override GCC's stack checking by providing a
1505 run-time routine to call to check the stack, so provide a mechanism for
1506 calling that routine. */
1507
1508 static GTY(()) rtx stack_check_libfunc;
1509
1510 void
set_stack_check_libfunc(const char * libfunc_name)1511 set_stack_check_libfunc (const char *libfunc_name)
1512 {
1513 gcc_assert (stack_check_libfunc == NULL_RTX);
1514 stack_check_libfunc = gen_rtx_SYMBOL_REF (Pmode, libfunc_name);
1515 }
1516
1517 /* Emit one stack probe at ADDRESS, an address within the stack. */
1518
1519 void
emit_stack_probe(rtx address)1520 emit_stack_probe (rtx address)
1521 {
1522 #ifdef HAVE_probe_stack_address
1523 if (HAVE_probe_stack_address)
1524 emit_insn (gen_probe_stack_address (address));
1525 else
1526 #endif
1527 {
1528 rtx memref = gen_rtx_MEM (word_mode, address);
1529
1530 MEM_VOLATILE_P (memref) = 1;
1531
1532 /* See if we have an insn to probe the stack. */
1533 #ifdef HAVE_probe_stack
1534 if (HAVE_probe_stack)
1535 emit_insn (gen_probe_stack (memref));
1536 else
1537 #endif
1538 emit_move_insn (memref, const0_rtx);
1539 }
1540 }
1541
1542 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1543 FIRST is a constant and size is a Pmode RTX. These are offsets from
1544 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
1545 or subtract them from the stack pointer. */
1546
1547 #define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
1548
1549 #ifdef STACK_GROWS_DOWNWARD
1550 #define STACK_GROW_OP MINUS
1551 #define STACK_GROW_OPTAB sub_optab
1552 #define STACK_GROW_OFF(off) -(off)
1553 #else
1554 #define STACK_GROW_OP PLUS
1555 #define STACK_GROW_OPTAB add_optab
1556 #define STACK_GROW_OFF(off) (off)
1557 #endif
1558
1559 void
probe_stack_range(HOST_WIDE_INT first,rtx size)1560 probe_stack_range (HOST_WIDE_INT first, rtx size)
1561 {
1562 /* First ensure SIZE is Pmode. */
1563 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1564 size = convert_to_mode (Pmode, size, 1);
1565
1566 /* Next see if we have a function to check the stack. */
1567 if (stack_check_libfunc)
1568 {
1569 rtx addr = memory_address (Pmode,
1570 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1571 stack_pointer_rtx,
1572 plus_constant (Pmode,
1573 size, first)));
1574 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1575 Pmode);
1576 }
1577
1578 /* Next see if we have an insn to check the stack. */
1579 #ifdef HAVE_check_stack
1580 else if (HAVE_check_stack)
1581 {
1582 struct expand_operand ops[1];
1583 rtx addr = memory_address (Pmode,
1584 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1585 stack_pointer_rtx,
1586 plus_constant (Pmode,
1587 size, first)));
1588 bool success;
1589 create_input_operand (&ops[0], addr, Pmode);
1590 success = maybe_expand_insn (CODE_FOR_check_stack, 1, ops);
1591 gcc_assert (success);
1592 }
1593 #endif
1594
1595 /* Otherwise we have to generate explicit probes. If we have a constant
1596 small number of them to generate, that's the easy case. */
1597 else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
1598 {
1599 HOST_WIDE_INT isize = INTVAL (size), i;
1600 rtx addr;
1601
1602 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
1603 it exceeds SIZE. If only one probe is needed, this will not
1604 generate any code. Then probe at FIRST + SIZE. */
1605 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
1606 {
1607 addr = memory_address (Pmode,
1608 plus_constant (Pmode, stack_pointer_rtx,
1609 STACK_GROW_OFF (first + i)));
1610 emit_stack_probe (addr);
1611 }
1612
1613 addr = memory_address (Pmode,
1614 plus_constant (Pmode, stack_pointer_rtx,
1615 STACK_GROW_OFF (first + isize)));
1616 emit_stack_probe (addr);
1617 }
1618
1619 /* In the variable case, do the same as above, but in a loop. Note that we
1620 must be extra careful with variables wrapping around because we might be
1621 at the very top (or the very bottom) of the address space and we have to
1622 be able to handle this case properly; in particular, we use an equality
1623 test for the loop condition. */
1624 else
1625 {
1626 rtx rounded_size, rounded_size_op, test_addr, last_addr, temp;
1627 rtx loop_lab = gen_label_rtx ();
1628 rtx end_lab = gen_label_rtx ();
1629
1630
1631 /* Step 1: round SIZE to the previous multiple of the interval. */
1632
1633 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1634 rounded_size
1635 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL));
1636 rounded_size_op = force_operand (rounded_size, NULL_RTX);
1637
1638
1639 /* Step 2: compute initial and final value of the loop counter. */
1640
1641 /* TEST_ADDR = SP + FIRST. */
1642 test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1643 stack_pointer_rtx,
1644 GEN_INT (first)), NULL_RTX);
1645
1646 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
1647 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1648 test_addr,
1649 rounded_size_op), NULL_RTX);
1650
1651
1652 /* Step 3: the loop
1653
1654 while (TEST_ADDR != LAST_ADDR)
1655 {
1656 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
1657 probe at TEST_ADDR
1658 }
1659
1660 probes at FIRST + N * PROBE_INTERVAL for values of N from 1
1661 until it is equal to ROUNDED_SIZE. */
1662
1663 emit_label (loop_lab);
1664
1665 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
1666 emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1,
1667 end_lab);
1668
1669 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
1670 temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr,
1671 GEN_INT (PROBE_INTERVAL), test_addr,
1672 1, OPTAB_WIDEN);
1673
1674 gcc_assert (temp == test_addr);
1675
1676 /* Probe at TEST_ADDR. */
1677 emit_stack_probe (test_addr);
1678
1679 emit_jump (loop_lab);
1680
1681 emit_label (end_lab);
1682
1683
1684 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
1685 that SIZE is equal to ROUNDED_SIZE. */
1686
1687 /* TEMP = SIZE - ROUNDED_SIZE. */
1688 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
1689 if (temp != const0_rtx)
1690 {
1691 rtx addr;
1692
1693 if (CONST_INT_P (temp))
1694 {
1695 /* Use [base + disp} addressing mode if supported. */
1696 HOST_WIDE_INT offset = INTVAL (temp);
1697 addr = memory_address (Pmode,
1698 plus_constant (Pmode, last_addr,
1699 STACK_GROW_OFF (offset)));
1700 }
1701 else
1702 {
1703 /* Manual CSE if the difference is not known at compile-time. */
1704 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
1705 addr = memory_address (Pmode,
1706 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1707 last_addr, temp));
1708 }
1709
1710 emit_stack_probe (addr);
1711 }
1712 }
1713 }
1714
1715 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
1716 while probing it. This pushes when SIZE is positive. SIZE need not
1717 be constant. If ADJUST_BACK is true, adjust back the stack pointer
1718 by plus SIZE at the end. */
1719
1720 void
anti_adjust_stack_and_probe(rtx size,bool adjust_back)1721 anti_adjust_stack_and_probe (rtx size, bool adjust_back)
1722 {
1723 /* We skip the probe for the first interval + a small dope of 4 words and
1724 probe that many bytes past the specified size to maintain a protection
1725 area at the botton of the stack. */
1726 const int dope = 4 * UNITS_PER_WORD;
1727
1728 /* First ensure SIZE is Pmode. */
1729 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1730 size = convert_to_mode (Pmode, size, 1);
1731
1732 /* If we have a constant small number of probes to generate, that's the
1733 easy case. */
1734 if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
1735 {
1736 HOST_WIDE_INT isize = INTVAL (size), i;
1737 bool first_probe = true;
1738
1739 /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
1740 values of N from 1 until it exceeds SIZE. If only one probe is
1741 needed, this will not generate any code. Then adjust and probe
1742 to PROBE_INTERVAL + SIZE. */
1743 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
1744 {
1745 if (first_probe)
1746 {
1747 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope));
1748 first_probe = false;
1749 }
1750 else
1751 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
1752 emit_stack_probe (stack_pointer_rtx);
1753 }
1754
1755 if (first_probe)
1756 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
1757 else
1758 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL - i));
1759 emit_stack_probe (stack_pointer_rtx);
1760 }
1761
1762 /* In the variable case, do the same as above, but in a loop. Note that we
1763 must be extra careful with variables wrapping around because we might be
1764 at the very top (or the very bottom) of the address space and we have to
1765 be able to handle this case properly; in particular, we use an equality
1766 test for the loop condition. */
1767 else
1768 {
1769 rtx rounded_size, rounded_size_op, last_addr, temp;
1770 rtx loop_lab = gen_label_rtx ();
1771 rtx end_lab = gen_label_rtx ();
1772
1773
1774 /* Step 1: round SIZE to the previous multiple of the interval. */
1775
1776 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1777 rounded_size
1778 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL));
1779 rounded_size_op = force_operand (rounded_size, NULL_RTX);
1780
1781
1782 /* Step 2: compute initial and final value of the loop counter. */
1783
1784 /* SP = SP_0 + PROBE_INTERVAL. */
1785 anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
1786
1787 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
1788 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1789 stack_pointer_rtx,
1790 rounded_size_op), NULL_RTX);
1791
1792
1793 /* Step 3: the loop
1794
1795 while (SP != LAST_ADDR)
1796 {
1797 SP = SP + PROBE_INTERVAL
1798 probe at SP
1799 }
1800
1801 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
1802 values of N from 1 until it is equal to ROUNDED_SIZE. */
1803
1804 emit_label (loop_lab);
1805
1806 /* Jump to END_LAB if SP == LAST_ADDR. */
1807 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
1808 Pmode, 1, end_lab);
1809
1810 /* SP = SP + PROBE_INTERVAL and probe at SP. */
1811 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
1812 emit_stack_probe (stack_pointer_rtx);
1813
1814 emit_jump (loop_lab);
1815
1816 emit_label (end_lab);
1817
1818
1819 /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
1820 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
1821
1822 /* TEMP = SIZE - ROUNDED_SIZE. */
1823 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
1824 if (temp != const0_rtx)
1825 {
1826 /* Manual CSE if the difference is not known at compile-time. */
1827 if (GET_CODE (temp) != CONST_INT)
1828 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
1829 anti_adjust_stack (temp);
1830 emit_stack_probe (stack_pointer_rtx);
1831 }
1832 }
1833
1834 /* Adjust back and account for the additional first interval. */
1835 if (adjust_back)
1836 adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
1837 else
1838 adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
1839 }
1840
1841 /* Return an rtx representing the register or memory location
1842 in which a scalar value of data type VALTYPE
1843 was returned by a function call to function FUNC.
1844 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1845 function is known, otherwise 0.
1846 OUTGOING is 1 if on a machine with register windows this function
1847 should return the register in which the function will put its result
1848 and 0 otherwise. */
1849
1850 rtx
hard_function_value(const_tree valtype,const_tree func,const_tree fntype,int outgoing ATTRIBUTE_UNUSED)1851 hard_function_value (const_tree valtype, const_tree func, const_tree fntype,
1852 int outgoing ATTRIBUTE_UNUSED)
1853 {
1854 rtx val;
1855
1856 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
1857
1858 if (REG_P (val)
1859 && GET_MODE (val) == BLKmode)
1860 {
1861 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1862 enum machine_mode tmpmode;
1863
1864 /* int_size_in_bytes can return -1. We don't need a check here
1865 since the value of bytes will then be large enough that no
1866 mode will match anyway. */
1867
1868 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1869 tmpmode != VOIDmode;
1870 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1871 {
1872 /* Have we found a large enough mode? */
1873 if (GET_MODE_SIZE (tmpmode) >= bytes)
1874 break;
1875 }
1876
1877 /* No suitable mode found. */
1878 gcc_assert (tmpmode != VOIDmode);
1879
1880 PUT_MODE (val, tmpmode);
1881 }
1882 return val;
1883 }
1884
1885 /* Return an rtx representing the register or memory location
1886 in which a scalar value of mode MODE was returned by a library call. */
1887
1888 rtx
hard_libcall_value(enum machine_mode mode,rtx fun)1889 hard_libcall_value (enum machine_mode mode, rtx fun)
1890 {
1891 return targetm.calls.libcall_value (mode, fun);
1892 }
1893
1894 /* Look up the tree code for a given rtx code
1895 to provide the arithmetic operation for REAL_ARITHMETIC.
1896 The function returns an int because the caller may not know
1897 what `enum tree_code' means. */
1898
1899 int
rtx_to_tree_code(enum rtx_code code)1900 rtx_to_tree_code (enum rtx_code code)
1901 {
1902 enum tree_code tcode;
1903
1904 switch (code)
1905 {
1906 case PLUS:
1907 tcode = PLUS_EXPR;
1908 break;
1909 case MINUS:
1910 tcode = MINUS_EXPR;
1911 break;
1912 case MULT:
1913 tcode = MULT_EXPR;
1914 break;
1915 case DIV:
1916 tcode = RDIV_EXPR;
1917 break;
1918 case SMIN:
1919 tcode = MIN_EXPR;
1920 break;
1921 case SMAX:
1922 tcode = MAX_EXPR;
1923 break;
1924 default:
1925 tcode = LAST_AND_UNUSED_TREE_CODE;
1926 break;
1927 }
1928 return ((int) tcode);
1929 }
1930
1931 #include "gt-explow.h"
1932