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08df6c0d
AO
1/* Infrastructure for tracking user variable locations and values
2 throughout compilation.
23a5b65a 3 Copyright (C) 2010-2014 Free Software Foundation, Inc.
08df6c0d
AO
4 Contributed by Alexandre Oliva <aoliva@redhat.com>.
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 3, or (at your option) any later
11version.
12
13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16for more details.
17
18You should have received a copy of the GNU General Public License
19along with GCC; see the file COPYING3. If not see
20<http://www.gnu.org/licenses/>. */
21
22#include "config.h"
23#include "system.h"
24#include "coretypes.h"
25#include "tm.h"
26#include "rtl.h"
27#include "valtrack.h"
28#include "function.h"
29#include "regs.h"
30#include "emit-rtl.h"
31
e90c56c6
JJ
32/* gen_lowpart_no_emit hook implementation for DEBUG_INSNs. In DEBUG_INSNs,
33 all lowpart SUBREGs are valid, despite what the machine requires for
34 instructions. */
35
36static rtx
37gen_lowpart_for_debug (enum machine_mode mode, rtx x)
38{
39 rtx result = gen_lowpart_if_possible (mode, x);
40 if (result)
41 return result;
42
43 if (GET_MODE (x) != VOIDmode)
44 return gen_rtx_raw_SUBREG (mode, x,
45 subreg_lowpart_offset (mode, GET_MODE (x)));
46
47 return NULL_RTX;
48}
49
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50/* Replace auto-increment addressing modes with explicit operations to access
51 the same addresses without modifying the corresponding registers. */
52
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53static rtx
54cleanup_auto_inc_dec (rtx src, enum machine_mode mem_mode ATTRIBUTE_UNUSED)
55{
56 rtx x = src;
375e3d07 57#ifdef AUTO_INC_DEC
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58 const RTX_CODE code = GET_CODE (x);
59 int i;
60 const char *fmt;
61
62 switch (code)
63 {
64 case REG:
d8116890 65 CASE_CONST_ANY:
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AO
66 case SYMBOL_REF:
67 case CODE_LABEL:
68 case PC:
69 case CC0:
70 case SCRATCH:
71 /* SCRATCH must be shared because they represent distinct values. */
72 return x;
73 case CLOBBER:
c5c5ba89
JH
74 /* Share clobbers of hard registers (like cc0), but do not share pseudo reg
75 clobbers or clobbers of hard registers that originated as pseudos.
76 This is needed to allow safe register renaming. */
77 if (REG_P (XEXP (x, 0)) && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER
78 && ORIGINAL_REGNO (XEXP (x, 0)) == REGNO (XEXP (x, 0)))
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79 return x;
80 break;
81
82 case CONST:
83 if (shared_const_p (x))
84 return x;
85 break;
86
87 case MEM:
88 mem_mode = GET_MODE (x);
89 break;
90
91 case PRE_INC:
92 case PRE_DEC:
93 gcc_assert (mem_mode != VOIDmode && mem_mode != BLKmode);
94 return gen_rtx_PLUS (GET_MODE (x),
95 cleanup_auto_inc_dec (XEXP (x, 0), mem_mode),
4789c0ce
RS
96 gen_int_mode (code == PRE_INC
97 ? GET_MODE_SIZE (mem_mode)
98 : -GET_MODE_SIZE (mem_mode),
99 GET_MODE (x)));
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100
101 case POST_INC:
102 case POST_DEC:
103 case PRE_MODIFY:
104 case POST_MODIFY:
105 return cleanup_auto_inc_dec (code == PRE_MODIFY
106 ? XEXP (x, 1) : XEXP (x, 0),
107 mem_mode);
108
109 default:
110 break;
111 }
112
113 /* Copy the various flags, fields, and other information. We assume
114 that all fields need copying, and then clear the fields that should
115 not be copied. That is the sensible default behavior, and forces
116 us to explicitly document why we are *not* copying a flag. */
117 x = shallow_copy_rtx (x);
118
119 /* We do not copy the USED flag, which is used as a mark bit during
120 walks over the RTL. */
121 RTX_FLAG (x, used) = 0;
122
123 /* We do not copy FRAME_RELATED for INSNs. */
124 if (INSN_P (x))
125 RTX_FLAG (x, frame_related) = 0;
126
127 fmt = GET_RTX_FORMAT (code);
128 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
129 if (fmt[i] == 'e')
130 XEXP (x, i) = cleanup_auto_inc_dec (XEXP (x, i), mem_mode);
131 else if (fmt[i] == 'E' || fmt[i] == 'V')
132 {
133 int j;
134 XVEC (x, i) = rtvec_alloc (XVECLEN (x, i));
135 for (j = 0; j < XVECLEN (x, i); j++)
136 XVECEXP (x, i, j)
137 = cleanup_auto_inc_dec (XVECEXP (src, i, j), mem_mode);
138 }
139
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140#else /* !AUTO_INC_DEC */
141 x = copy_rtx (x);
142#endif /* !AUTO_INC_DEC */
143
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144 return x;
145}
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146
147/* Auxiliary data structure for propagate_for_debug_stmt. */
148
149struct rtx_subst_pair
150{
151 rtx to;
152 bool adjusted;
153};
154
155/* DATA points to an rtx_subst_pair. Return the value that should be
156 substituted. */
157
158static rtx
159propagate_for_debug_subst (rtx from, const_rtx old_rtx, void *data)
160{
161 struct rtx_subst_pair *pair = (struct rtx_subst_pair *)data;
162
163 if (!rtx_equal_p (from, old_rtx))
164 return NULL_RTX;
165 if (!pair->adjusted)
166 {
167 pair->adjusted = true;
08df6c0d 168 pair->to = cleanup_auto_inc_dec (pair->to, VOIDmode);
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169 pair->to = make_compound_operation (pair->to, SET);
170 return pair->to;
171 }
172 return copy_rtx (pair->to);
173}
174
175/* Replace all the occurrences of DEST with SRC in DEBUG_INSNs between INSN
176 and LAST, not including INSN, but including LAST. Also stop at the end
177 of THIS_BASIC_BLOCK. */
178
179void
180propagate_for_debug (rtx insn, rtx last, rtx dest, rtx src,
181 basic_block this_basic_block)
182{
183 rtx next, loc, end = NEXT_INSN (BB_END (this_basic_block));
e90c56c6 184 rtx (*saved_rtl_hook_no_emit) (enum machine_mode, rtx);
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185
186 struct rtx_subst_pair p;
187 p.to = src;
188 p.adjusted = false;
189
190 next = NEXT_INSN (insn);
191 last = NEXT_INSN (last);
e90c56c6
JJ
192 saved_rtl_hook_no_emit = rtl_hooks.gen_lowpart_no_emit;
193 rtl_hooks.gen_lowpart_no_emit = gen_lowpart_for_debug;
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194 while (next != last && next != end)
195 {
196 insn = next;
197 next = NEXT_INSN (insn);
198 if (DEBUG_INSN_P (insn))
199 {
200 loc = simplify_replace_fn_rtx (INSN_VAR_LOCATION_LOC (insn),
201 dest, propagate_for_debug_subst, &p);
202 if (loc == INSN_VAR_LOCATION_LOC (insn))
203 continue;
204 INSN_VAR_LOCATION_LOC (insn) = loc;
205 df_insn_rescan (insn);
206 }
207 }
e90c56c6 208 rtl_hooks.gen_lowpart_no_emit = saved_rtl_hook_no_emit;
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209}
210
211/* Initialize DEBUG to an empty list, and clear USED, if given. */
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212
213void
214dead_debug_global_init (struct dead_debug_global *debug, bitmap used)
215{
216 debug->used = used;
c203e8a7 217 debug->htab = NULL;
e9f950ba
AO
218 if (used)
219 bitmap_clear (used);
220}
221
222/* Initialize DEBUG to an empty list, and clear USED, if given. Link
223 back to GLOBAL, if given, and bring in used bits from it. */
224
08df6c0d 225void
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226dead_debug_local_init (struct dead_debug_local *debug, bitmap used,
227 struct dead_debug_global *global)
08df6c0d 228{
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229 if (!used && global && global->used)
230 used = BITMAP_ALLOC (NULL);
231
08df6c0d 232 debug->head = NULL;
e9f950ba 233 debug->global = global;
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234 debug->used = used;
235 debug->to_rescan = NULL;
e9f950ba 236
08df6c0d 237 if (used)
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AO
238 {
239 if (global && global->used)
240 bitmap_copy (used, global->used);
241 else
242 bitmap_clear (used);
243 }
244}
245
246/* Locate the entry for REG in GLOBAL->htab. */
247
248static dead_debug_global_entry *
249dead_debug_global_find (struct dead_debug_global *global, rtx reg)
250{
251 dead_debug_global_entry temp_entry;
252 temp_entry.reg = reg;
253
c203e8a7 254 dead_debug_global_entry *entry = global->htab->find (&temp_entry);
e9f950ba 255 gcc_checking_assert (entry && entry->reg == temp_entry.reg);
e9f950ba
AO
256
257 return entry;
258}
259
260/* Insert an entry mapping REG to DTEMP in GLOBAL->htab. */
261
0e45ec20 262static dead_debug_global_entry *
e9f950ba
AO
263dead_debug_global_insert (struct dead_debug_global *global, rtx reg, rtx dtemp)
264{
265 dead_debug_global_entry temp_entry;
266 temp_entry.reg = reg;
267 temp_entry.dtemp = dtemp;
268
c203e8a7
TS
269 if (!global->htab)
270 global->htab = new hash_table<dead_debug_hash_descr> (31);
e9f950ba 271
c203e8a7
TS
272 dead_debug_global_entry **slot = global->htab->find_slot (&temp_entry,
273 INSERT);
e9f950ba
AO
274 gcc_checking_assert (!*slot);
275 *slot = XNEW (dead_debug_global_entry);
276 **slot = temp_entry;
0e45ec20 277 return *slot;
e9f950ba
AO
278}
279
280/* If UREGNO, referenced by USE, is a pseudo marked as used in GLOBAL,
281 replace it with with a USE of the debug temp recorded for it, and
282 return TRUE. Otherwise, just return FALSE.
283
284 If PTO_RESCAN is given, instead of rescanning modified INSNs right
285 away, add their UIDs to the bitmap, allocating one of *PTO_RESCAN
286 is NULL. */
287
288static bool
289dead_debug_global_replace_temp (struct dead_debug_global *global,
290 df_ref use, unsigned int uregno,
291 bitmap *pto_rescan)
292{
293 if (!global || uregno < FIRST_PSEUDO_REGISTER
294 || !global->used
0e45ec20
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295 || !REG_P (*DF_REF_REAL_LOC (use))
296 || REGNO (*DF_REF_REAL_LOC (use)) != uregno
e9f950ba
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297 || !bitmap_bit_p (global->used, uregno))
298 return false;
299
e9f950ba
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300 dead_debug_global_entry *entry
301 = dead_debug_global_find (global, *DF_REF_REAL_LOC (use));
302 gcc_checking_assert (GET_CODE (entry->reg) == REG
303 && REGNO (entry->reg) == uregno);
304
0e45ec20
AO
305 if (!entry->dtemp)
306 return true;
307
e9f950ba
AO
308 *DF_REF_REAL_LOC (use) = entry->dtemp;
309 if (!pto_rescan)
310 df_insn_rescan (DF_REF_INSN (use));
311 else
312 {
313 if (!*pto_rescan)
314 *pto_rescan = BITMAP_ALLOC (NULL);
315 bitmap_set_bit (*pto_rescan, INSN_UID (DF_REF_INSN (use)));
316 }
317
318 return true;
08df6c0d
AO
319}
320
321/* Reset all debug uses in HEAD, and clear DEBUG->to_rescan bits of
322 each reset insn. DEBUG is not otherwise modified. If HEAD is
323 DEBUG->head, DEBUG->head will be set to NULL at the end.
324 Otherwise, entries from DEBUG->head that pertain to reset insns
325 will be removed, and only then rescanned. */
326
327static void
e9f950ba
AO
328dead_debug_reset_uses (struct dead_debug_local *debug,
329 struct dead_debug_use *head)
08df6c0d
AO
330{
331 bool got_head = (debug->head == head);
332 bitmap rescan;
333 struct dead_debug_use **tailp = &debug->head;
334 struct dead_debug_use *cur;
335 bitmap_iterator bi;
336 unsigned int uid;
337
338 if (got_head)
339 rescan = NULL;
340 else
341 rescan = BITMAP_ALLOC (NULL);
342
343 while (head)
344 {
345 struct dead_debug_use *next = head->next;
346 rtx insn;
347
348 insn = DF_REF_INSN (head->use);
349 if (!next || DF_REF_INSN (next->use) != insn)
350 {
351 INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC ();
352 if (got_head)
353 df_insn_rescan_debug_internal (insn);
354 else
355 bitmap_set_bit (rescan, INSN_UID (insn));
356 if (debug->to_rescan)
357 bitmap_clear_bit (debug->to_rescan, INSN_UID (insn));
358 }
359 XDELETE (head);
360 head = next;
361 }
362
363 if (got_head)
364 {
365 debug->head = NULL;
366 return;
367 }
368
369 while ((cur = *tailp))
370 if (bitmap_bit_p (rescan, INSN_UID (DF_REF_INSN (cur->use))))
371 {
372 *tailp = cur->next;
373 XDELETE (cur);
374 }
375 else
376 tailp = &cur->next;
377
378 EXECUTE_IF_SET_IN_BITMAP (rescan, 0, uid, bi)
379 {
380 struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid);
381 if (insn_info)
382 df_insn_rescan_debug_internal (insn_info->insn);
383 }
384
385 BITMAP_FREE (rescan);
386}
387
e9f950ba
AO
388/* Promote pending local uses of pseudos in DEBUG to global
389 substitutions. Uses of non-pseudos are left alone for
390 resetting. */
391
392static void
393dead_debug_promote_uses (struct dead_debug_local *debug)
394{
395 for (struct dead_debug_use *head = debug->head, **headp = &debug->head;
396 head; head = *headp)
397 {
398 rtx reg = *DF_REF_REAL_LOC (head->use);
0e45ec20
AO
399 df_ref ref;
400 dead_debug_global_entry *entry;
e9f950ba
AO
401
402 if (GET_CODE (reg) != REG
403 || REGNO (reg) < FIRST_PSEUDO_REGISTER)
404 {
405 headp = &head->next;
406 continue;
407 }
408
409 if (!debug->global->used)
410 debug->global->used = BITMAP_ALLOC (NULL);
411
f39b1a1a
AO
412 bool added = bitmap_set_bit (debug->global->used, REGNO (reg));
413 gcc_checking_assert (added);
414
415 entry = dead_debug_global_insert (debug->global, reg,
416 make_debug_expr_from_rtl (reg));
e9f950ba 417
0e45ec20
AO
418 gcc_checking_assert (entry->dtemp);
419
420 /* Tentatively remove the USE from the list. */
e9f950ba 421 *headp = head->next;
0e45ec20
AO
422
423 if (!debug->to_rescan)
424 debug->to_rescan = BITMAP_ALLOC (NULL);
425
426 for (ref = DF_REG_USE_CHAIN (REGNO (reg)); ref;
427 ref = DF_REF_NEXT_REG (ref))
428 if (DEBUG_INSN_P (DF_REF_INSN (ref)))
429 {
430 if (!dead_debug_global_replace_temp (debug->global, ref,
431 REGNO (reg),
432 &debug->to_rescan))
433 {
434 rtx insn = DF_REF_INSN (ref);
435 INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC ();
436 bitmap_set_bit (debug->to_rescan, INSN_UID (insn));
437 }
438 }
439
440 for (ref = DF_REG_DEF_CHAIN (REGNO (reg)); ref;
441 ref = DF_REF_NEXT_REG (ref))
442 if (!dead_debug_insert_temp (debug, REGNO (reg), DF_REF_INSN (ref),
443 DEBUG_TEMP_BEFORE_WITH_VALUE))
444 {
445 rtx bind;
446 bind = gen_rtx_VAR_LOCATION (GET_MODE (reg),
447 DEBUG_EXPR_TREE_DECL (entry->dtemp),
448 gen_rtx_UNKNOWN_VAR_LOC (),
449 VAR_INIT_STATUS_INITIALIZED);
450 rtx insn = emit_debug_insn_before (bind, DF_REF_INSN (ref));
451 bitmap_set_bit (debug->to_rescan, INSN_UID (insn));
452 }
453
454 entry->dtemp = NULL;
e9f950ba
AO
455 XDELETE (head);
456 }
457}
458
08df6c0d
AO
459/* Reset all debug insns with pending uses. Release the bitmap in it,
460 unless it is USED. USED must be the same bitmap passed to
e9f950ba
AO
461 dead_debug_local_init. */
462
08df6c0d 463void
e9f950ba 464dead_debug_local_finish (struct dead_debug_local *debug, bitmap used)
08df6c0d 465{
e9f950ba
AO
466 if (debug->global)
467 dead_debug_promote_uses (debug);
468
0e45ec20
AO
469 if (debug->used != used)
470 BITMAP_FREE (debug->used);
471
08df6c0d
AO
472 dead_debug_reset_uses (debug, debug->head);
473
474 if (debug->to_rescan)
475 {
476 bitmap_iterator bi;
477 unsigned int uid;
478
479 EXECUTE_IF_SET_IN_BITMAP (debug->to_rescan, 0, uid, bi)
480 {
481 struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid);
482 if (insn_info)
483 df_insn_rescan (insn_info->insn);
484 }
485 BITMAP_FREE (debug->to_rescan);
486 }
487}
488
e9f950ba
AO
489/* Release GLOBAL->used unless it is the same as USED. Release the
490 mapping hash table if it was initialized. */
491
492void
493dead_debug_global_finish (struct dead_debug_global *global, bitmap used)
494{
495 if (global->used != used)
496 BITMAP_FREE (global->used);
497
c203e8a7
TS
498 delete global->htab;
499 global->htab = NULL;
e9f950ba
AO
500}
501
502/* Add USE to DEBUG, or substitute it right away if it's a pseudo in
503 the global substitution list. USE must be a dead reference to
504 UREGNO in a debug insn. Create a bitmap for DEBUG as needed. */
505
08df6c0d 506void
e9f950ba 507dead_debug_add (struct dead_debug_local *debug, df_ref use, unsigned int uregno)
08df6c0d 508{
e9f950ba
AO
509 if (dead_debug_global_replace_temp (debug->global, use, uregno,
510 &debug->to_rescan))
511 return;
512
08df6c0d
AO
513 struct dead_debug_use *newddu = XNEW (struct dead_debug_use);
514
515 newddu->use = use;
516 newddu->next = debug->head;
517 debug->head = newddu;
518
519 if (!debug->used)
520 debug->used = BITMAP_ALLOC (NULL);
521
522 /* ??? If we dealt with split multi-registers below, we should set
523 all registers for the used mode in case of hardware
524 registers. */
525 bitmap_set_bit (debug->used, uregno);
526}
527
528/* If UREGNO is referenced by any entry in DEBUG, emit a debug insn
e9f950ba
AO
529 before or after INSN (depending on WHERE), that binds a (possibly
530 global) debug temp to the widest-mode use of UREGNO, if WHERE is
531 *_WITH_REG, or the value stored in UREGNO by INSN otherwise, and
532 replace all uses of UREGNO in DEBUG with uses of the debug temp.
533 INSN must be where UREGNO dies, if WHERE is *_BEFORE_*, or where it
534 is set otherwise. Return the number of debug insns emitted. */
535
08df6c0d 536int
e9f950ba 537dead_debug_insert_temp (struct dead_debug_local *debug, unsigned int uregno,
08df6c0d
AO
538 rtx insn, enum debug_temp_where where)
539{
540 struct dead_debug_use **tailp = &debug->head;
541 struct dead_debug_use *cur;
542 struct dead_debug_use *uses = NULL;
543 struct dead_debug_use **usesp = &uses;
e9f950ba 544 rtx reg = NULL_RTX;
08df6c0d 545 rtx breg;
e9f950ba 546 rtx dval = NULL_RTX;
08df6c0d 547 rtx bind;
e9f950ba 548 bool global;
08df6c0d 549
e9f950ba
AO
550 if (!debug->used)
551 return 0;
552
553 global = (debug->global && debug->global->used
554 && bitmap_bit_p (debug->global->used, uregno));
555
556 if (!global && !bitmap_clear_bit (debug->used, uregno))
08df6c0d
AO
557 return 0;
558
559 /* Move all uses of uregno from debug->head to uses, setting mode to
560 the widest referenced mode. */
561 while ((cur = *tailp))
562 {
563 if (DF_REF_REGNO (cur->use) == uregno)
564 {
d540153b
JJ
565 /* If this loc has been changed e.g. to debug_expr already
566 as part of a multi-register use, just drop it. */
567 if (!REG_P (*DF_REF_REAL_LOC (cur->use)))
568 {
569 *tailp = cur->next;
570 XDELETE (cur);
571 continue;
572 }
08df6c0d
AO
573 *usesp = cur;
574 usesp = &cur->next;
575 *tailp = cur->next;
576 cur->next = NULL;
577 if (!reg
578 || (GET_MODE_BITSIZE (GET_MODE (reg))
579 < GET_MODE_BITSIZE (GET_MODE (*DF_REF_REAL_LOC (cur->use)))))
580 reg = *DF_REF_REAL_LOC (cur->use);
581 }
582 else
583 tailp = &(*tailp)->next;
584 }
585
586 /* We may have dangling bits in debug->used for registers that were part
587 of a multi-register use, one component of which has been reset. */
588 if (reg == NULL)
589 {
590 gcc_checking_assert (!uses);
e9f950ba
AO
591 if (!global)
592 return 0;
593 }
594
595 if (global)
596 {
597 if (!reg)
598 reg = regno_reg_rtx[uregno];
599 dead_debug_global_entry *entry
600 = dead_debug_global_find (debug->global, reg);
601 gcc_checking_assert (entry->reg == reg);
602 dval = entry->dtemp;
0e45ec20
AO
603 if (!dval)
604 return 0;
08df6c0d
AO
605 }
606
e9f950ba 607 gcc_checking_assert (uses || global);
08df6c0d
AO
608
609 breg = reg;
610 /* Recover the expression INSN stores in REG. */
611 if (where == DEBUG_TEMP_BEFORE_WITH_VALUE)
612 {
613 rtx set = single_set (insn);
614 rtx dest, src;
615
616 if (set)
617 {
618 dest = SET_DEST (set);
619 src = SET_SRC (set);
620 /* Lose if the REG-setting insn is a CALL. */
621 if (GET_CODE (src) == CALL)
622 {
623 while (uses)
624 {
625 cur = uses->next;
626 XDELETE (uses);
627 uses = cur;
628 }
629 return 0;
630 }
631 }
632
633 /* ??? Should we try to extract it from a PARALLEL? */
634 if (!set)
635 breg = NULL;
636 /* Cool, it's the same REG, we can use SRC. */
637 else if (dest == reg)
e7206ab1 638 breg = cleanup_auto_inc_dec (src, VOIDmode);
08df6c0d
AO
639 else if (REG_P (dest))
640 {
641 /* Hmm... Something's fishy, we should be setting REG here. */
642 if (REGNO (dest) != REGNO (reg))
643 breg = NULL;
644 /* If we're not overwriting all the hardware registers that
645 setting REG in its mode would, we won't know what to bind
646 the debug temp to. ??? We could bind the debug_expr to a
647 CONCAT or PARALLEL with the split multi-registers, and
648 replace them as we found the corresponding sets. */
649 else if (REGNO (reg) < FIRST_PSEUDO_REGISTER
650 && (hard_regno_nregs[REGNO (reg)][GET_MODE (reg)]
651 != hard_regno_nregs[REGNO (reg)][GET_MODE (dest)]))
652 breg = NULL;
653 /* Ok, it's the same (hardware) REG, but with a different
654 mode, so SUBREG it. */
655 else
e7206ab1
AO
656 breg = lowpart_subreg (GET_MODE (reg),
657 cleanup_auto_inc_dec (src, VOIDmode),
08df6c0d
AO
658 GET_MODE (dest));
659 }
660 else if (GET_CODE (dest) == SUBREG)
661 {
662 /* We should be setting REG here. Lose. */
663 if (REGNO (SUBREG_REG (dest)) != REGNO (reg))
664 breg = NULL;
665 /* Lose if we're setting something other than the lowpart of
666 REG. */
667 else if (!subreg_lowpart_p (dest))
668 breg = NULL;
669 /* If we're not overwriting all the hardware registers that
670 setting REG in its mode would, we won't know what to bind
671 the debug temp to. */
672 else if (REGNO (reg) < FIRST_PSEUDO_REGISTER
673 && (hard_regno_nregs[REGNO (reg)][GET_MODE (reg)]
674 != hard_regno_nregs[REGNO (reg)][GET_MODE (dest)]))
675 breg = NULL;
676 /* Yay, we can use SRC, just adjust its mode. */
677 else
e7206ab1
AO
678 breg = lowpart_subreg (GET_MODE (reg),
679 cleanup_auto_inc_dec (src, VOIDmode),
08df6c0d
AO
680 GET_MODE (dest));
681 }
682 /* Oh well, we're out of luck. */
683 else
684 breg = NULL;
685
686 /* We couldn't figure out the value stored in REG, so reset all
687 of its pending debug uses. */
688 if (!breg)
689 {
690 dead_debug_reset_uses (debug, uses);
691 return 0;
692 }
693 }
694
695 /* If there's a single (debug) use of an otherwise unused REG, and
696 the debug use is not part of a larger expression, then it
697 probably doesn't make sense to introduce a new debug temp. */
698 if (where == DEBUG_TEMP_AFTER_WITH_REG && !uses->next)
699 {
700 rtx next = DF_REF_INSN (uses->use);
701
702 if (DEBUG_INSN_P (next) && reg == INSN_VAR_LOCATION_LOC (next))
703 {
704 XDELETE (uses);
705 return 0;
706 }
707 }
708
e9f950ba
AO
709 if (!global)
710 /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */
711 dval = make_debug_expr_from_rtl (reg);
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AO
712
713 /* Emit a debug bind insn before the insn in which reg dies. */
714 bind = gen_rtx_VAR_LOCATION (GET_MODE (reg),
715 DEBUG_EXPR_TREE_DECL (dval), breg,
716 VAR_INIT_STATUS_INITIALIZED);
717
85d87497
JJ
718 if (where == DEBUG_TEMP_AFTER_WITH_REG
719 || where == DEBUG_TEMP_AFTER_WITH_REG_FORCE)
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AO
720 bind = emit_debug_insn_after (bind, insn);
721 else
722 bind = emit_debug_insn_before (bind, insn);
36290bb4
AO
723 if (debug->to_rescan == NULL)
724 debug->to_rescan = BITMAP_ALLOC (NULL);
725 bitmap_set_bit (debug->to_rescan, INSN_UID (bind));
08df6c0d
AO
726
727 /* Adjust all uses. */
728 while ((cur = uses))
729 {
730 if (GET_MODE (*DF_REF_REAL_LOC (cur->use)) == GET_MODE (reg))
731 *DF_REF_REAL_LOC (cur->use) = dval;
732 else
733 *DF_REF_REAL_LOC (cur->use)
734 = gen_lowpart_SUBREG (GET_MODE (*DF_REF_REAL_LOC (cur->use)), dval);
735 /* ??? Should we simplify subreg of subreg? */
08df6c0d
AO
736 bitmap_set_bit (debug->to_rescan, INSN_UID (DF_REF_INSN (cur->use)));
737 uses = cur->next;
738 XDELETE (cur);
739 }
740
741 return 1;
742}
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