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Commit | Line | Data |
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6de9cd9a DN |
1 | /* Miscellaneous SSA utility functions. |
2 | Copyright (C) 2001, 2002, 2003, 2004 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 | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GCC is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GCC; see the file COPYING. If not, write to | |
18 | the Free Software Foundation, 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
24 | #include "tm.h" | |
25 | #include "tree.h" | |
26 | #include "flags.h" | |
27 | #include "rtl.h" | |
28 | #include "tm_p.h" | |
29 | #include "ggc.h" | |
30 | #include "langhooks.h" | |
31 | #include "hard-reg-set.h" | |
32 | #include "basic-block.h" | |
33 | #include "output.h" | |
34 | #include "errors.h" | |
35 | #include "expr.h" | |
36 | #include "function.h" | |
37 | #include "diagnostic.h" | |
38 | #include "bitmap.h" | |
39 | #include "tree-flow.h" | |
eadf906f | 40 | #include "tree-gimple.h" |
6de9cd9a DN |
41 | #include "tree-inline.h" |
42 | #include "varray.h" | |
43 | #include "timevar.h" | |
6de9cd9a DN |
44 | #include "hashtab.h" |
45 | #include "tree-dump.h" | |
46 | #include "tree-pass.h" | |
47 | ||
48 | ||
49 | /* Remove edge E and remove the corresponding arguments from the PHI nodes | |
50 | in E's destination block. */ | |
51 | ||
52 | void | |
53 | ssa_remove_edge (edge e) | |
54 | { | |
55 | tree phi, next; | |
56 | ||
57 | /* Remove the appropriate PHI arguments in E's destination block. */ | |
58 | for (phi = phi_nodes (e->dest); phi; phi = next) | |
59 | { | |
17192884 | 60 | next = PHI_CHAIN (phi); |
6de9cd9a DN |
61 | remove_phi_arg (phi, e->src); |
62 | } | |
63 | ||
64 | remove_edge (e); | |
65 | } | |
66 | ||
f6144c34 BE |
67 | /* Remove the corresponding arguments from the PHI nodes in E's |
68 | destination block and redirect it to DEST. Return redirected edge. | |
6de9cd9a DN |
69 | The list of removed arguments is stored in PENDING_STMT (e). */ |
70 | ||
71 | edge | |
72 | ssa_redirect_edge (edge e, basic_block dest) | |
73 | { | |
74 | tree phi, next; | |
75 | tree list = NULL, *last = &list; | |
76 | tree src, dst, node; | |
77 | int i; | |
78 | ||
79 | /* Remove the appropriate PHI arguments in E's destination block. */ | |
80 | for (phi = phi_nodes (e->dest); phi; phi = next) | |
81 | { | |
17192884 | 82 | next = PHI_CHAIN (phi); |
6de9cd9a DN |
83 | |
84 | i = phi_arg_from_edge (phi, e); | |
85 | if (i < 0) | |
86 | continue; | |
87 | ||
88 | src = PHI_ARG_DEF (phi, i); | |
89 | dst = PHI_RESULT (phi); | |
90 | node = build_tree_list (dst, src); | |
91 | *last = node; | |
92 | last = &TREE_CHAIN (node); | |
93 | ||
94 | remove_phi_arg_num (phi, i); | |
95 | } | |
96 | ||
97 | e = redirect_edge_succ_nodup (e, dest); | |
98 | PENDING_STMT (e) = list; | |
99 | ||
100 | return e; | |
101 | } | |
102 | ||
103 | ||
53b4bf74 | 104 | /* Return true if SSA_NAME is malformed and mark it visited. |
6de9cd9a | 105 | |
53b4bf74 DN |
106 | IS_VIRTUAL is true if this SSA_NAME was found inside a virtual |
107 | operand. */ | |
6de9cd9a DN |
108 | |
109 | static bool | |
53b4bf74 | 110 | verify_ssa_name (tree ssa_name, bool is_virtual) |
6de9cd9a | 111 | { |
53b4bf74 | 112 | TREE_VISITED (ssa_name) = 1; |
6de9cd9a DN |
113 | |
114 | if (TREE_CODE (ssa_name) != SSA_NAME) | |
115 | { | |
116 | error ("Expected an SSA_NAME object"); | |
53b4bf74 | 117 | return true; |
6de9cd9a DN |
118 | } |
119 | ||
bbc630f5 DN |
120 | if (TREE_TYPE (ssa_name) != TREE_TYPE (SSA_NAME_VAR (ssa_name))) |
121 | { | |
122 | error ("Type mismatch between an SSA_NAME and its symbol."); | |
123 | return true; | |
124 | } | |
125 | ||
53b4bf74 DN |
126 | if (SSA_NAME_IN_FREE_LIST (ssa_name)) |
127 | { | |
128 | error ("Found an SSA_NAME that had been released into the free pool"); | |
129 | return true; | |
130 | } | |
131 | ||
132 | if (is_virtual && is_gimple_reg (ssa_name)) | |
133 | { | |
134 | error ("Found a virtual definition for a GIMPLE register"); | |
135 | return true; | |
136 | } | |
137 | ||
138 | if (!is_virtual && !is_gimple_reg (ssa_name)) | |
139 | { | |
140 | error ("Found a real definition for a non-register"); | |
141 | return true; | |
142 | } | |
143 | ||
144 | return false; | |
145 | } | |
146 | ||
147 | ||
148 | /* Return true if the definition of SSA_NAME at block BB is malformed. | |
149 | ||
150 | STMT is the statement where SSA_NAME is created. | |
151 | ||
152 | DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME | |
153 | version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set, | |
154 | it means that the block in that array slot contains the | |
155 | definition of SSA_NAME. | |
156 | ||
157 | IS_VIRTUAL is true if SSA_NAME is created by a V_MAY_DEF or a | |
158 | V_MUST_DEF. */ | |
159 | ||
160 | static bool | |
161 | verify_def (basic_block bb, basic_block *definition_block, tree ssa_name, | |
162 | tree stmt, bool is_virtual) | |
163 | { | |
164 | if (verify_ssa_name (ssa_name, is_virtual)) | |
165 | goto err; | |
166 | ||
6de9cd9a DN |
167 | if (definition_block[SSA_NAME_VERSION (ssa_name)]) |
168 | { | |
169 | error ("SSA_NAME created in two different blocks %i and %i", | |
170 | definition_block[SSA_NAME_VERSION (ssa_name)]->index, bb->index); | |
53b4bf74 | 171 | goto err; |
6de9cd9a DN |
172 | } |
173 | ||
174 | definition_block[SSA_NAME_VERSION (ssa_name)] = bb; | |
175 | ||
176 | if (SSA_NAME_DEF_STMT (ssa_name) != stmt) | |
177 | { | |
178 | error ("SSA_NAME_DEF_STMT is wrong"); | |
6de9cd9a | 179 | fprintf (stderr, "Expected definition statement:\n"); |
7bab95ba | 180 | print_generic_stmt (stderr, SSA_NAME_DEF_STMT (ssa_name), TDF_VOPS); |
6de9cd9a | 181 | fprintf (stderr, "\nActual definition statement:\n"); |
7bab95ba | 182 | print_generic_stmt (stderr, stmt, TDF_VOPS); |
53b4bf74 | 183 | goto err; |
6de9cd9a DN |
184 | } |
185 | ||
53b4bf74 DN |
186 | return false; |
187 | ||
188 | err: | |
189 | fprintf (stderr, "while verifying SSA_NAME "); | |
190 | print_generic_expr (stderr, ssa_name, 0); | |
191 | fprintf (stderr, " in statement\n"); | |
7bab95ba | 192 | print_generic_stmt (stderr, stmt, TDF_VOPS); |
53b4bf74 DN |
193 | |
194 | return true; | |
6de9cd9a DN |
195 | } |
196 | ||
197 | ||
198 | /* Return true if the use of SSA_NAME at statement STMT in block BB is | |
199 | malformed. | |
200 | ||
201 | DEF_BB is the block where SSA_NAME was found to be created. | |
202 | ||
203 | IDOM contains immediate dominator information for the flowgraph. | |
204 | ||
205 | CHECK_ABNORMAL is true if the caller wants to check whether this use | |
206 | is flowing through an abnormal edge (only used when checking PHI | |
53b4bf74 DN |
207 | arguments). |
208 | ||
209 | IS_VIRTUAL is true if SSA_NAME is created by a V_MAY_DEF or a | |
b1d16eff ZD |
210 | V_MUST_DEF. |
211 | ||
212 | If NAMES_DEFINED_IN_BB is not NULL, it contains a bitmap of ssa names | |
213 | that are defined before STMT in basic block BB. */ | |
6de9cd9a DN |
214 | |
215 | static bool | |
216 | verify_use (basic_block bb, basic_block def_bb, tree ssa_name, | |
b1d16eff ZD |
217 | tree stmt, bool check_abnormal, bool is_virtual, |
218 | bitmap names_defined_in_bb) | |
6de9cd9a DN |
219 | { |
220 | bool err = false; | |
221 | ||
53b4bf74 DN |
222 | err = verify_ssa_name (ssa_name, is_virtual); |
223 | ||
224 | if (IS_EMPTY_STMT (SSA_NAME_DEF_STMT (ssa_name)) | |
225 | && var_ann (SSA_NAME_VAR (ssa_name))->default_def == ssa_name) | |
226 | ; /* Default definitions have empty statements. Nothing to do. */ | |
6de9cd9a DN |
227 | else if (!def_bb) |
228 | { | |
229 | error ("Missing definition"); | |
230 | err = true; | |
231 | } | |
232 | else if (bb != def_bb | |
233 | && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) | |
234 | { | |
235 | error ("Definition in block %i does not dominate use in block %i", | |
236 | def_bb->index, bb->index); | |
237 | err = true; | |
238 | } | |
b1d16eff ZD |
239 | else if (bb == def_bb |
240 | && names_defined_in_bb != NULL | |
241 | && !bitmap_bit_p (names_defined_in_bb, SSA_NAME_VERSION (ssa_name))) | |
242 | { | |
243 | error ("Definition in block %i follows the use", def_bb->index); | |
244 | err = true; | |
245 | } | |
6de9cd9a DN |
246 | |
247 | if (check_abnormal | |
248 | && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssa_name)) | |
249 | { | |
250 | error ("SSA_NAME_OCCURS_IN_ABNORMAL_PHI should be set"); | |
251 | err = true; | |
252 | } | |
253 | ||
254 | if (err) | |
255 | { | |
256 | fprintf (stderr, "for SSA_NAME: "); | |
7bab95ba | 257 | print_generic_expr (stderr, ssa_name, TDF_VOPS); |
6de9cd9a | 258 | fprintf (stderr, "in statement:\n"); |
7bab95ba | 259 | print_generic_stmt (stderr, stmt, TDF_VOPS); |
6de9cd9a DN |
260 | } |
261 | ||
262 | return err; | |
263 | } | |
264 | ||
265 | ||
266 | /* Return true if any of the arguments for PHI node PHI at block BB is | |
267 | malformed. | |
268 | ||
269 | IDOM contains immediate dominator information for the flowgraph. | |
270 | ||
271 | DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME version | |
272 | numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set, it means that the | |
273 | block in that array slot contains the definition of SSA_NAME. */ | |
274 | ||
275 | static bool | |
276 | verify_phi_args (tree phi, basic_block bb, basic_block *definition_block) | |
277 | { | |
278 | edge e; | |
279 | bool err = false; | |
280 | int i, phi_num_args = PHI_NUM_ARGS (phi); | |
628f6a4e | 281 | edge_iterator ei; |
6de9cd9a DN |
282 | |
283 | /* Mark all the incoming edges. */ | |
628f6a4e | 284 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
285 | e->aux = (void *) 1; |
286 | ||
287 | for (i = 0; i < phi_num_args; i++) | |
288 | { | |
289 | tree op = PHI_ARG_DEF (phi, i); | |
290 | ||
291 | e = PHI_ARG_EDGE (phi, i); | |
292 | ||
293 | if (TREE_CODE (op) == SSA_NAME) | |
53b4bf74 DN |
294 | err = verify_use (e->src, definition_block[SSA_NAME_VERSION (op)], op, |
295 | phi, e->flags & EDGE_ABNORMAL, | |
b1d16eff ZD |
296 | !is_gimple_reg (PHI_RESULT (phi)), |
297 | NULL); | |
6de9cd9a DN |
298 | |
299 | if (e->dest != bb) | |
300 | { | |
301 | error ("Wrong edge %d->%d for PHI argument\n", | |
302 | e->src->index, e->dest->index, bb->index); | |
303 | err = true; | |
304 | } | |
305 | ||
306 | if (e->aux == (void *) 0) | |
307 | { | |
308 | error ("PHI argument flowing through dead edge %d->%d\n", | |
309 | e->src->index, e->dest->index); | |
310 | err = true; | |
311 | } | |
312 | ||
313 | if (e->aux == (void *) 2) | |
314 | { | |
315 | error ("PHI argument duplicated for edge %d->%d\n", e->src->index, | |
316 | e->dest->index); | |
317 | err = true; | |
318 | } | |
319 | ||
320 | if (err) | |
321 | { | |
322 | fprintf (stderr, "PHI argument\n"); | |
7bab95ba | 323 | print_generic_stmt (stderr, op, TDF_VOPS); |
53b4bf74 | 324 | goto error; |
6de9cd9a DN |
325 | } |
326 | ||
327 | e->aux = (void *) 2; | |
328 | } | |
329 | ||
628f6a4e | 330 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
331 | { |
332 | if (e->aux != (void *) 2) | |
333 | { | |
334 | error ("No argument flowing through edge %d->%d\n", e->src->index, | |
335 | e->dest->index); | |
336 | err = true; | |
53b4bf74 | 337 | goto error; |
6de9cd9a DN |
338 | } |
339 | e->aux = (void *) 0; | |
340 | } | |
341 | ||
53b4bf74 | 342 | error: |
6de9cd9a DN |
343 | if (err) |
344 | { | |
345 | fprintf (stderr, "for PHI node\n"); | |
7bab95ba | 346 | print_generic_stmt (stderr, phi, TDF_VOPS); |
6de9cd9a DN |
347 | } |
348 | ||
349 | ||
350 | return err; | |
351 | } | |
352 | ||
353 | ||
53b4bf74 DN |
354 | static void |
355 | verify_flow_insensitive_alias_info (void) | |
356 | { | |
357 | size_t i; | |
358 | tree var; | |
359 | bitmap visited = BITMAP_XMALLOC (); | |
360 | ||
361 | for (i = 0; i < num_referenced_vars; i++) | |
362 | { | |
852c7b12 | 363 | size_t j; |
53b4bf74 | 364 | var_ann_t ann; |
852c7b12 | 365 | varray_type may_aliases; |
53b4bf74 DN |
366 | |
367 | var = referenced_var (i); | |
368 | ann = var_ann (var); | |
852c7b12 | 369 | may_aliases = ann->may_aliases; |
53b4bf74 | 370 | |
852c7b12 | 371 | for (j = 0; may_aliases && j < VARRAY_ACTIVE_SIZE (may_aliases); j++) |
53b4bf74 | 372 | { |
852c7b12 | 373 | tree alias = VARRAY_TREE (may_aliases, j); |
53b4bf74 | 374 | |
852c7b12 | 375 | bitmap_set_bit (visited, var_ann (alias)->uid); |
53b4bf74 | 376 | |
852c7b12 DN |
377 | if (!may_be_aliased (alias)) |
378 | { | |
379 | error ("Non-addressable variable inside an alias set."); | |
380 | debug_variable (alias); | |
381 | goto err; | |
53b4bf74 DN |
382 | } |
383 | } | |
384 | } | |
385 | ||
386 | for (i = 0; i < num_referenced_vars; i++) | |
387 | { | |
388 | var_ann_t ann; | |
389 | ||
390 | var = referenced_var (i); | |
391 | ann = var_ann (var); | |
392 | ||
393 | if (ann->mem_tag_kind == NOT_A_TAG | |
394 | && ann->is_alias_tag | |
395 | && !bitmap_bit_p (visited, ann->uid)) | |
396 | { | |
397 | error ("Addressable variable that is an alias tag but is not in any alias set."); | |
398 | goto err; | |
399 | } | |
400 | } | |
401 | ||
402 | BITMAP_XFREE (visited); | |
403 | return; | |
404 | ||
405 | err: | |
406 | debug_variable (var); | |
407 | internal_error ("verify_flow_insensitive_alias_info failed."); | |
408 | } | |
409 | ||
410 | ||
411 | static void | |
412 | verify_flow_sensitive_alias_info (void) | |
413 | { | |
414 | size_t i; | |
415 | tree ptr; | |
416 | ||
417 | for (i = 1; i < num_ssa_names; i++) | |
418 | { | |
419 | var_ann_t ann; | |
420 | struct ptr_info_def *pi; | |
421 | ||
422 | ptr = ssa_name (i); | |
8b547e44 JH |
423 | if (!ptr) |
424 | continue; | |
53b4bf74 DN |
425 | ann = var_ann (SSA_NAME_VAR (ptr)); |
426 | pi = SSA_NAME_PTR_INFO (ptr); | |
427 | ||
428 | /* We only care for pointers that are actually referenced in the | |
429 | program. */ | |
430 | if (!TREE_VISITED (ptr) || !POINTER_TYPE_P (TREE_TYPE (ptr))) | |
431 | continue; | |
432 | ||
433 | /* RESULT_DECL is special. If it's a GIMPLE register, then it | |
434 | is only written-to only once in the return statement. | |
435 | Otherwise, aggregate RESULT_DECLs may be written-to more than | |
436 | once in virtual operands. */ | |
437 | if (TREE_CODE (SSA_NAME_VAR (ptr)) == RESULT_DECL | |
438 | && is_gimple_reg (ptr)) | |
439 | continue; | |
440 | ||
441 | if (pi == NULL) | |
442 | continue; | |
443 | ||
444 | if (pi->is_dereferenced && !pi->name_mem_tag && !ann->type_mem_tag) | |
445 | { | |
446 | error ("Dereferenced pointers should have a name or a type tag"); | |
447 | goto err; | |
448 | } | |
449 | ||
53b4bf74 DN |
450 | if (pi->name_mem_tag |
451 | && !pi->pt_malloc | |
452 | && (pi->pt_vars == NULL | |
453 | || bitmap_first_set_bit (pi->pt_vars) < 0)) | |
454 | { | |
455 | error ("Pointers with a memory tag, should have points-to sets or point to malloc"); | |
456 | goto err; | |
457 | } | |
458 | ||
459 | if (pi->value_escapes_p | |
460 | && pi->name_mem_tag | |
461 | && !is_call_clobbered (pi->name_mem_tag)) | |
462 | { | |
463 | error ("Pointer escapes but its name tag is not call-clobbered."); | |
464 | goto err; | |
465 | } | |
466 | ||
467 | if (pi->name_mem_tag && pi->pt_vars) | |
468 | { | |
469 | size_t j; | |
470 | ||
471 | for (j = i + 1; j < num_ssa_names; j++) | |
8b547e44 JH |
472 | if (ssa_name (j)) |
473 | { | |
474 | tree ptr2 = ssa_name (j); | |
475 | struct ptr_info_def *pi2 = SSA_NAME_PTR_INFO (ptr2); | |
476 | ||
477 | if (!TREE_VISITED (ptr2) || !POINTER_TYPE_P (TREE_TYPE (ptr2))) | |
478 | continue; | |
479 | ||
480 | if (pi2 | |
481 | && pi2->name_mem_tag | |
482 | && pi2->pt_vars | |
483 | && bitmap_first_set_bit (pi2->pt_vars) >= 0 | |
484 | && pi->name_mem_tag != pi2->name_mem_tag | |
485 | && bitmap_equal_p (pi->pt_vars, pi2->pt_vars)) | |
486 | { | |
487 | error ("Two pointers with different name tags and identical points-to sets"); | |
488 | debug_variable (ptr2); | |
489 | goto err; | |
490 | } | |
491 | } | |
53b4bf74 DN |
492 | } |
493 | } | |
494 | ||
495 | return; | |
496 | ||
497 | err: | |
498 | debug_variable (ptr); | |
499 | internal_error ("verify_flow_sensitive_alias_info failed."); | |
500 | } | |
501 | ||
502 | ||
503 | /* Verify the consistency of aliasing information. */ | |
504 | ||
505 | static void | |
506 | verify_alias_info (void) | |
507 | { | |
c1b763fa DN |
508 | verify_flow_sensitive_alias_info (); |
509 | verify_flow_insensitive_alias_info (); | |
53b4bf74 DN |
510 | } |
511 | ||
512 | ||
6de9cd9a DN |
513 | /* Verify common invariants in the SSA web. |
514 | TODO: verify the variable annotations. */ | |
515 | ||
516 | void | |
517 | verify_ssa (void) | |
518 | { | |
53b4bf74 | 519 | size_t i; |
6de9cd9a | 520 | basic_block bb; |
95a3742c | 521 | basic_block *definition_block = xcalloc (num_ssa_names, sizeof (basic_block)); |
4c124b4c AM |
522 | ssa_op_iter iter; |
523 | tree op; | |
03261822 | 524 | enum dom_state orig_dom_state = dom_computed[CDI_DOMINATORS]; |
b1d16eff | 525 | bitmap names_defined_in_bb = BITMAP_XMALLOC (); |
6de9cd9a DN |
526 | |
527 | timevar_push (TV_TREE_SSA_VERIFY); | |
528 | ||
53b4bf74 DN |
529 | /* Keep track of SSA names present in the IL. */ |
530 | for (i = 1; i < num_ssa_names; i++) | |
8b547e44 JH |
531 | if (ssa_name (i)) |
532 | TREE_VISITED (ssa_name (i)) = 0; | |
53b4bf74 | 533 | |
6de9cd9a DN |
534 | calculate_dominance_info (CDI_DOMINATORS); |
535 | ||
536 | /* Verify and register all the SSA_NAME definitions found in the | |
537 | function. */ | |
538 | FOR_EACH_BB (bb) | |
539 | { | |
540 | tree phi; | |
541 | block_stmt_iterator bsi; | |
542 | ||
17192884 | 543 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
53b4bf74 DN |
544 | if (verify_def (bb, definition_block, PHI_RESULT (phi), phi, |
545 | !is_gimple_reg (PHI_RESULT (phi)))) | |
546 | goto err; | |
6de9cd9a DN |
547 | |
548 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
549 | { | |
550 | tree stmt; | |
6de9cd9a DN |
551 | |
552 | stmt = bsi_stmt (bsi); | |
6de9cd9a DN |
553 | get_stmt_operands (stmt); |
554 | ||
4c124b4c AM |
555 | if (stmt_ann (stmt)->makes_aliased_stores |
556 | && NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt)) == 0) | |
53b4bf74 DN |
557 | { |
558 | error ("Statement makes aliased stores, but has no V_MAY_DEFS"); | |
7bab95ba | 559 | print_generic_stmt (stderr, stmt, TDF_VOPS); |
53b4bf74 DN |
560 | goto err; |
561 | } | |
a32b97a2 | 562 | |
4c124b4c | 563 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_VIRTUAL_DEFS) |
6de9cd9a | 564 | { |
53b4bf74 DN |
565 | if (verify_def (bb, definition_block, op, stmt, true)) |
566 | goto err; | |
6de9cd9a | 567 | } |
a32b97a2 | 568 | |
4c124b4c | 569 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF) |
a32b97a2 | 570 | { |
53b4bf74 DN |
571 | if (verify_def (bb, definition_block, op, stmt, false)) |
572 | goto err; | |
6de9cd9a DN |
573 | } |
574 | } | |
575 | } | |
576 | ||
577 | ||
578 | /* Now verify all the uses and make sure they agree with the definitions | |
579 | found in the previous pass. */ | |
580 | FOR_EACH_BB (bb) | |
581 | { | |
582 | edge e; | |
583 | tree phi; | |
628f6a4e | 584 | edge_iterator ei; |
6de9cd9a DN |
585 | block_stmt_iterator bsi; |
586 | ||
587 | /* Make sure that all edges have a clear 'aux' field. */ | |
628f6a4e | 588 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
589 | { |
590 | if (e->aux) | |
591 | { | |
592 | error ("AUX pointer initialized for edge %d->%d\n", e->src->index, | |
593 | e->dest->index); | |
53b4bf74 | 594 | goto err; |
6de9cd9a DN |
595 | } |
596 | } | |
597 | ||
598 | /* Verify the arguments for every PHI node in the block. */ | |
17192884 | 599 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
b1d16eff ZD |
600 | { |
601 | if (verify_phi_args (phi, bb, definition_block)) | |
602 | goto err; | |
603 | bitmap_set_bit (names_defined_in_bb, | |
604 | SSA_NAME_VERSION (PHI_RESULT (phi))); | |
605 | } | |
6de9cd9a | 606 | |
53b4bf74 | 607 | /* Now verify all the uses and vuses in every statement of the block. */ |
6de9cd9a DN |
608 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) |
609 | { | |
610 | tree stmt = bsi_stmt (bsi); | |
6de9cd9a | 611 | |
4c124b4c | 612 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_VIRTUAL_USES) |
6de9cd9a | 613 | { |
53b4bf74 | 614 | if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)], |
b1d16eff ZD |
615 | op, stmt, false, true, |
616 | names_defined_in_bb)) | |
53b4bf74 | 617 | goto err; |
6de9cd9a DN |
618 | } |
619 | ||
4c124b4c | 620 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE) |
6de9cd9a | 621 | { |
53b4bf74 | 622 | if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)], |
b1d16eff ZD |
623 | op, stmt, false, false, |
624 | names_defined_in_bb)) | |
625 | goto err; | |
626 | } | |
627 | ||
628 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_ALL_DEFS) | |
629 | { | |
630 | bitmap_set_bit (names_defined_in_bb, SSA_NAME_VERSION (op)); | |
631 | } | |
632 | } | |
633 | ||
634 | /* Verify the uses in arguments of PHI nodes at the exits from the | |
635 | block. */ | |
628f6a4e | 636 | FOR_EACH_EDGE (e, ei, bb->succs) |
b1d16eff ZD |
637 | { |
638 | for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi)) | |
639 | { | |
640 | bool virtual = !is_gimple_reg (PHI_RESULT (phi)); | |
641 | op = PHI_ARG_DEF_FROM_EDGE (phi, e); | |
642 | if (TREE_CODE (op) != SSA_NAME) | |
643 | continue; | |
644 | ||
645 | if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)], | |
646 | op, phi, false, virtual, | |
647 | names_defined_in_bb)) | |
53b4bf74 | 648 | goto err; |
6de9cd9a DN |
649 | } |
650 | } | |
b1d16eff ZD |
651 | |
652 | bitmap_clear (names_defined_in_bb); | |
6de9cd9a DN |
653 | } |
654 | ||
53b4bf74 DN |
655 | /* Finally, verify alias information. */ |
656 | verify_alias_info (); | |
6de9cd9a | 657 | |
53b4bf74 | 658 | free (definition_block); |
b01d837f KH |
659 | /* Restore the dominance information to its prior known state, so |
660 | that we do not perturb the compiler's subsequent behavior. */ | |
03261822 NS |
661 | if (orig_dom_state == DOM_NONE) |
662 | free_dominance_info (CDI_DOMINATORS); | |
663 | else | |
664 | dom_computed[CDI_DOMINATORS] = orig_dom_state; | |
665 | ||
b1d16eff | 666 | BITMAP_XFREE (names_defined_in_bb); |
6de9cd9a | 667 | timevar_pop (TV_TREE_SSA_VERIFY); |
53b4bf74 | 668 | return; |
6de9cd9a | 669 | |
53b4bf74 DN |
670 | err: |
671 | internal_error ("verify_ssa failed."); | |
6de9cd9a DN |
672 | } |
673 | ||
674 | ||
6de9cd9a DN |
675 | /* Initialize global DFA and SSA structures. */ |
676 | ||
677 | void | |
678 | init_tree_ssa (void) | |
679 | { | |
680 | VARRAY_TREE_INIT (referenced_vars, 20, "referenced_vars"); | |
681 | call_clobbered_vars = BITMAP_XMALLOC (); | |
a6d02559 | 682 | addressable_vars = BITMAP_XMALLOC (); |
6de9cd9a DN |
683 | init_ssa_operands (); |
684 | init_ssanames (); | |
685 | init_phinodes (); | |
686 | global_var = NULL_TREE; | |
6de9cd9a DN |
687 | } |
688 | ||
689 | ||
690 | /* Deallocate memory associated with SSA data structures for FNDECL. */ | |
691 | ||
692 | void | |
693 | delete_tree_ssa (void) | |
694 | { | |
695 | size_t i; | |
696 | basic_block bb; | |
697 | block_stmt_iterator bsi; | |
698 | ||
699 | /* Remove annotations from every tree in the function. */ | |
700 | FOR_EACH_BB (bb) | |
701 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
80d8221e JH |
702 | { |
703 | tree stmt = bsi_stmt (bsi); | |
704 | release_defs (stmt); | |
705 | ggc_free (stmt->common.ann); | |
706 | stmt->common.ann = NULL; | |
707 | } | |
6de9cd9a DN |
708 | |
709 | /* Remove annotations from every referenced variable. */ | |
710 | if (referenced_vars) | |
711 | { | |
712 | for (i = 0; i < num_referenced_vars; i++) | |
80d8221e JH |
713 | { |
714 | tree var = referenced_var (i); | |
715 | ggc_free (var->common.ann); | |
716 | var->common.ann = NULL; | |
717 | } | |
6de9cd9a DN |
718 | referenced_vars = NULL; |
719 | } | |
720 | ||
721 | fini_ssanames (); | |
722 | fini_phinodes (); | |
723 | fini_ssa_operands (); | |
724 | ||
725 | global_var = NULL_TREE; | |
6b9bee8e | 726 | BITMAP_XFREE (call_clobbered_vars); |
6de9cd9a | 727 | call_clobbered_vars = NULL; |
a6d02559 DN |
728 | BITMAP_XFREE (addressable_vars); |
729 | addressable_vars = NULL; | |
6de9cd9a DN |
730 | } |
731 | ||
732 | ||
733 | /* Return true if EXPR is a useless type conversion, otherwise return | |
734 | false. */ | |
735 | ||
736 | bool | |
737 | tree_ssa_useless_type_conversion_1 (tree outer_type, tree inner_type) | |
738 | { | |
739 | /* If the inner and outer types are effectively the same, then | |
740 | strip the type conversion and enter the equivalence into | |
741 | the table. */ | |
742 | if (inner_type == outer_type | |
743 | || (lang_hooks.types_compatible_p (inner_type, outer_type))) | |
744 | return true; | |
745 | ||
746 | /* If both types are pointers and the outer type is a (void *), then | |
747 | the conversion is not necessary. The opposite is not true since | |
748 | that conversion would result in a loss of information if the | |
749 | equivalence was used. Consider an indirect function call where | |
750 | we need to know the exact type of the function to correctly | |
751 | implement the ABI. */ | |
752 | else if (POINTER_TYPE_P (inner_type) | |
753 | && POINTER_TYPE_P (outer_type) | |
754 | && TREE_CODE (TREE_TYPE (outer_type)) == VOID_TYPE) | |
755 | return true; | |
756 | ||
757 | /* Pointers and references are equivalent once we get to GENERIC, | |
758 | so strip conversions that just switch between them. */ | |
759 | else if (POINTER_TYPE_P (inner_type) | |
760 | && POINTER_TYPE_P (outer_type) | |
3facc4b6 AP |
761 | && lang_hooks.types_compatible_p (TREE_TYPE (inner_type), |
762 | TREE_TYPE (outer_type))) | |
6de9cd9a DN |
763 | return true; |
764 | ||
765 | /* If both the inner and outer types are integral types, then the | |
766 | conversion is not necessary if they have the same mode and | |
bc15d0ef JM |
767 | signedness and precision, and both or neither are boolean. Some |
768 | code assumes an invariant that boolean types stay boolean and do | |
769 | not become 1-bit bit-field types. Note that types with precision | |
770 | not using all bits of the mode (such as bit-field types in C) | |
771 | mean that testing of precision is necessary. */ | |
6de9cd9a DN |
772 | else if (INTEGRAL_TYPE_P (inner_type) |
773 | && INTEGRAL_TYPE_P (outer_type) | |
774 | && TYPE_MODE (inner_type) == TYPE_MODE (outer_type) | |
775 | && TYPE_UNSIGNED (inner_type) == TYPE_UNSIGNED (outer_type) | |
776 | && TYPE_PRECISION (inner_type) == TYPE_PRECISION (outer_type)) | |
bc15d0ef JM |
777 | { |
778 | bool first_boolean = (TREE_CODE (inner_type) == BOOLEAN_TYPE); | |
779 | bool second_boolean = (TREE_CODE (outer_type) == BOOLEAN_TYPE); | |
780 | if (first_boolean == second_boolean) | |
781 | return true; | |
782 | } | |
6de9cd9a DN |
783 | |
784 | /* Recurse for complex types. */ | |
785 | else if (TREE_CODE (inner_type) == COMPLEX_TYPE | |
786 | && TREE_CODE (outer_type) == COMPLEX_TYPE | |
787 | && tree_ssa_useless_type_conversion_1 (TREE_TYPE (outer_type), | |
788 | TREE_TYPE (inner_type))) | |
789 | return true; | |
790 | ||
791 | return false; | |
792 | } | |
793 | ||
794 | /* Return true if EXPR is a useless type conversion, otherwise return | |
795 | false. */ | |
796 | ||
797 | bool | |
798 | tree_ssa_useless_type_conversion (tree expr) | |
799 | { | |
800 | /* If we have an assignment that merely uses a NOP_EXPR to change | |
801 | the top of the RHS to the type of the LHS and the type conversion | |
802 | is "safe", then strip away the type conversion so that we can | |
803 | enter LHS = RHS into the const_and_copies table. */ | |
580d124f RK |
804 | if (TREE_CODE (expr) == NOP_EXPR || TREE_CODE (expr) == CONVERT_EXPR |
805 | || TREE_CODE (expr) == VIEW_CONVERT_EXPR | |
806 | || TREE_CODE (expr) == NON_LVALUE_EXPR) | |
6de9cd9a DN |
807 | return tree_ssa_useless_type_conversion_1 (TREE_TYPE (expr), |
808 | TREE_TYPE (TREE_OPERAND (expr, | |
809 | 0))); | |
810 | ||
811 | ||
812 | return false; | |
813 | } | |
814 | ||
815 | ||
816 | /* Internal helper for walk_use_def_chains. VAR, FN and DATA are as | |
53b4bf74 DN |
817 | described in walk_use_def_chains. |
818 | ||
819 | VISITED is a bitmap used to mark visited SSA_NAMEs to avoid | |
820 | infinite loops. | |
821 | ||
822 | IS_DFS is true if the caller wants to perform a depth-first search | |
823 | when visiting PHI nodes. A DFS will visit each PHI argument and | |
824 | call FN after each one. Otherwise, all the arguments are | |
825 | visited first and then FN is called with each of the visited | |
826 | arguments in a separate pass. */ | |
6de9cd9a DN |
827 | |
828 | static bool | |
829 | walk_use_def_chains_1 (tree var, walk_use_def_chains_fn fn, void *data, | |
53b4bf74 | 830 | bitmap visited, bool is_dfs) |
6de9cd9a DN |
831 | { |
832 | tree def_stmt; | |
833 | ||
834 | if (bitmap_bit_p (visited, SSA_NAME_VERSION (var))) | |
835 | return false; | |
836 | ||
837 | bitmap_set_bit (visited, SSA_NAME_VERSION (var)); | |
838 | ||
839 | def_stmt = SSA_NAME_DEF_STMT (var); | |
840 | ||
841 | if (TREE_CODE (def_stmt) != PHI_NODE) | |
842 | { | |
843 | /* If we reached the end of the use-def chain, call FN. */ | |
53b4bf74 | 844 | return fn (var, def_stmt, data); |
6de9cd9a DN |
845 | } |
846 | else | |
847 | { | |
848 | int i; | |
849 | ||
53b4bf74 DN |
850 | /* When doing a breadth-first search, call FN before following the |
851 | use-def links for each argument. */ | |
852 | if (!is_dfs) | |
853 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) | |
854 | if (fn (PHI_ARG_DEF (def_stmt, i), def_stmt, data)) | |
855 | return true; | |
856 | ||
857 | /* Follow use-def links out of each PHI argument. */ | |
6de9cd9a DN |
858 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) |
859 | { | |
860 | tree arg = PHI_ARG_DEF (def_stmt, i); | |
861 | if (TREE_CODE (arg) == SSA_NAME | |
53b4bf74 | 862 | && walk_use_def_chains_1 (arg, fn, data, visited, is_dfs)) |
6de9cd9a DN |
863 | return true; |
864 | } | |
53b4bf74 DN |
865 | |
866 | /* When doing a depth-first search, call FN after following the | |
867 | use-def links for each argument. */ | |
868 | if (is_dfs) | |
869 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) | |
870 | if (fn (PHI_ARG_DEF (def_stmt, i), def_stmt, data)) | |
871 | return true; | |
6de9cd9a | 872 | } |
53b4bf74 | 873 | |
6de9cd9a DN |
874 | return false; |
875 | } | |
876 | ||
877 | ||
878 | ||
53b4bf74 DN |
879 | /* Walk use-def chains starting at the SSA variable VAR. Call |
880 | function FN at each reaching definition found. FN takes three | |
881 | arguments: VAR, its defining statement (DEF_STMT) and a generic | |
882 | pointer to whatever state information that FN may want to maintain | |
883 | (DATA). FN is able to stop the walk by returning true, otherwise | |
884 | in order to continue the walk, FN should return false. | |
6de9cd9a DN |
885 | |
886 | Note, that if DEF_STMT is a PHI node, the semantics are slightly | |
53b4bf74 DN |
887 | different. The first argument to FN is no longer the original |
888 | variable VAR, but the PHI argument currently being examined. If FN | |
889 | wants to get at VAR, it should call PHI_RESULT (PHI). | |
890 | ||
891 | If IS_DFS is true, this function will: | |
6de9cd9a | 892 | |
53b4bf74 DN |
893 | 1- walk the use-def chains for all the PHI arguments, and, |
894 | 2- call (*FN) (ARG, PHI, DATA) on all the PHI arguments. | |
895 | ||
896 | If IS_DFS is false, the two steps above are done in reverse order | |
897 | (i.e., a breadth-first search). */ | |
6de9cd9a | 898 | |
6de9cd9a DN |
899 | |
900 | void | |
53b4bf74 DN |
901 | walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data, |
902 | bool is_dfs) | |
6de9cd9a DN |
903 | { |
904 | tree def_stmt; | |
905 | ||
1e128c5f | 906 | gcc_assert (TREE_CODE (var) == SSA_NAME); |
6de9cd9a DN |
907 | |
908 | def_stmt = SSA_NAME_DEF_STMT (var); | |
909 | ||
910 | /* We only need to recurse if the reaching definition comes from a PHI | |
911 | node. */ | |
912 | if (TREE_CODE (def_stmt) != PHI_NODE) | |
913 | (*fn) (var, def_stmt, data); | |
914 | else | |
915 | { | |
916 | bitmap visited = BITMAP_XMALLOC (); | |
53b4bf74 | 917 | walk_use_def_chains_1 (var, fn, data, visited, is_dfs); |
6de9cd9a DN |
918 | BITMAP_XFREE (visited); |
919 | } | |
920 | } | |
921 | ||
53b4bf74 | 922 | |
d7621d3c ZD |
923 | /* Replaces VAR with REPL in memory reference expression *X in |
924 | statement STMT. */ | |
925 | ||
926 | static void | |
927 | propagate_into_addr (tree stmt, tree var, tree *x, tree repl) | |
928 | { | |
929 | tree new_var, ass_stmt, addr_var; | |
930 | basic_block bb; | |
931 | block_stmt_iterator bsi; | |
932 | ||
933 | /* There is nothing special to handle in the other cases. */ | |
934 | if (TREE_CODE (repl) != ADDR_EXPR) | |
935 | return; | |
936 | addr_var = TREE_OPERAND (repl, 0); | |
937 | ||
0705d602 RK |
938 | while (handled_component_p (*x) |
939 | || TREE_CODE (*x) == REALPART_EXPR | |
940 | || TREE_CODE (*x) == IMAGPART_EXPR) | |
d7621d3c ZD |
941 | x = &TREE_OPERAND (*x, 0); |
942 | ||
943 | if (TREE_CODE (*x) != INDIRECT_REF | |
944 | || TREE_OPERAND (*x, 0) != var) | |
945 | return; | |
946 | ||
d7621d3c ZD |
947 | if (TREE_TYPE (*x) == TREE_TYPE (addr_var)) |
948 | { | |
949 | *x = addr_var; | |
950 | mark_new_vars_to_rename (stmt, vars_to_rename); | |
951 | return; | |
952 | } | |
953 | ||
68b9f53b | 954 | |
d7621d3c ZD |
955 | /* Frontends sometimes produce expressions like *&a instead of a[0]. |
956 | Create a temporary variable to handle this case. */ | |
957 | ass_stmt = build2 (MODIFY_EXPR, void_type_node, NULL_TREE, repl); | |
958 | new_var = duplicate_ssa_name (var, ass_stmt); | |
959 | TREE_OPERAND (*x, 0) = new_var; | |
960 | TREE_OPERAND (ass_stmt, 0) = new_var; | |
961 | ||
962 | bb = bb_for_stmt (stmt); | |
963 | tree_block_label (bb); | |
964 | bsi = bsi_after_labels (bb); | |
965 | bsi_insert_after (&bsi, ass_stmt, BSI_NEW_STMT); | |
966 | ||
967 | mark_new_vars_to_rename (stmt, vars_to_rename); | |
968 | } | |
6de9cd9a DN |
969 | |
970 | /* Replaces immediate uses of VAR by REPL. */ | |
971 | ||
972 | static void | |
973 | replace_immediate_uses (tree var, tree repl) | |
974 | { | |
6de9cd9a DN |
975 | int i, j, n; |
976 | dataflow_t df; | |
977 | tree stmt; | |
d7621d3c | 978 | bool mark_new_vars; |
4c124b4c AM |
979 | ssa_op_iter iter; |
980 | use_operand_p use_p; | |
6de9cd9a DN |
981 | |
982 | df = get_immediate_uses (SSA_NAME_DEF_STMT (var)); | |
983 | n = num_immediate_uses (df); | |
984 | ||
985 | for (i = 0; i < n; i++) | |
986 | { | |
987 | stmt = immediate_use (df, i); | |
6de9cd9a DN |
988 | |
989 | if (TREE_CODE (stmt) == PHI_NODE) | |
990 | { | |
991 | for (j = 0; j < PHI_NUM_ARGS (stmt); j++) | |
992 | if (PHI_ARG_DEF (stmt, j) == var) | |
993 | { | |
d00ad49b | 994 | SET_PHI_ARG_DEF (stmt, j, repl); |
6de9cd9a DN |
995 | if (TREE_CODE (repl) == SSA_NAME |
996 | && PHI_ARG_EDGE (stmt, j)->flags & EDGE_ABNORMAL) | |
997 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (repl) = 1; | |
998 | } | |
999 | ||
1000 | continue; | |
1001 | } | |
1002 | ||
1003 | get_stmt_operands (stmt); | |
d7621d3c | 1004 | mark_new_vars = false; |
6de9cd9a DN |
1005 | if (is_gimple_reg (SSA_NAME_VAR (var))) |
1006 | { | |
d7621d3c ZD |
1007 | if (TREE_CODE (stmt) == MODIFY_EXPR) |
1008 | { | |
1009 | propagate_into_addr (stmt, var, &TREE_OPERAND (stmt, 0), repl); | |
1010 | propagate_into_addr (stmt, var, &TREE_OPERAND (stmt, 1), repl); | |
1011 | } | |
1012 | ||
4c124b4c AM |
1013 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) |
1014 | if (USE_FROM_PTR (use_p) == var) | |
d7621d3c | 1015 | { |
4c124b4c | 1016 | propagate_value (use_p, repl); |
d7621d3c ZD |
1017 | mark_new_vars = POINTER_TYPE_P (TREE_TYPE (repl)); |
1018 | } | |
6de9cd9a DN |
1019 | } |
1020 | else | |
1021 | { | |
4c124b4c AM |
1022 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_VIRTUAL_USES) |
1023 | if (USE_FROM_PTR (use_p) == var) | |
1024 | propagate_value (use_p, repl); | |
6de9cd9a DN |
1025 | } |
1026 | ||
7eae8eb2 DN |
1027 | /* FIXME. If REPL is a constant, we need to fold STMT. |
1028 | However, fold_stmt wants a pointer to the statement, because | |
1029 | it may happen that it needs to replace the whole statement | |
1030 | with a new expression. Since the current def-use machinery | |
1031 | does not return pointers to statements, we call fold_stmt | |
1032 | with the address of a local temporary, if that call changes | |
1033 | the temporary then we fall on our swords. | |
1034 | ||
1035 | Note that all this will become unnecessary soon. This | |
1036 | pass is being replaced with a proper copy propagation pass | |
1037 | for 4.1 (dnovillo, 2004-09-17). */ | |
1038 | if (TREE_CODE (repl) != SSA_NAME) | |
1039 | { | |
1040 | tree tmp = stmt; | |
1041 | fold_stmt (&tmp); | |
1042 | if (tmp != stmt) | |
1043 | abort (); | |
1044 | } | |
1045 | ||
6de9cd9a DN |
1046 | /* If REPL is a pointer, it may have different memory tags associated |
1047 | with it. For instance, VAR may have had a name tag while REPL | |
1048 | only had a type tag. In these cases, the virtual operands (if | |
1049 | any) in the statement will refer to different symbols which need | |
1050 | to be renamed. */ | |
d7621d3c | 1051 | if (mark_new_vars) |
6de9cd9a | 1052 | mark_new_vars_to_rename (stmt, vars_to_rename); |
d7621d3c ZD |
1053 | else |
1054 | modify_stmt (stmt); | |
6de9cd9a DN |
1055 | } |
1056 | } | |
1057 | ||
048d9936 ZD |
1058 | /* Gets the value VAR is equivalent to according to EQ_TO. */ |
1059 | ||
1060 | static tree | |
1061 | get_eq_name (tree *eq_to, tree var) | |
1062 | { | |
1063 | unsigned ver; | |
1064 | tree val = var; | |
1065 | ||
1066 | while (TREE_CODE (val) == SSA_NAME) | |
1067 | { | |
1068 | ver = SSA_NAME_VERSION (val); | |
1069 | if (!eq_to[ver]) | |
1070 | break; | |
1071 | ||
1072 | val = eq_to[ver]; | |
1073 | } | |
1074 | ||
1075 | while (TREE_CODE (var) == SSA_NAME) | |
1076 | { | |
1077 | ver = SSA_NAME_VERSION (var); | |
1078 | if (!eq_to[ver]) | |
1079 | break; | |
1080 | ||
1081 | var = eq_to[ver]; | |
1082 | eq_to[ver] = val; | |
1083 | } | |
1084 | ||
1085 | return val; | |
1086 | } | |
1087 | ||
1088 | /* Checks whether phi node PHI is redundant and if it is, records the ssa name | |
1089 | its result is redundant to to EQ_TO array. */ | |
6de9cd9a DN |
1090 | |
1091 | static void | |
048d9936 | 1092 | check_phi_redundancy (tree phi, tree *eq_to) |
6de9cd9a | 1093 | { |
048d9936 ZD |
1094 | tree val = NULL_TREE, def, res = PHI_RESULT (phi), stmt; |
1095 | unsigned i, ver = SSA_NAME_VERSION (res), n; | |
6de9cd9a DN |
1096 | dataflow_t df; |
1097 | ||
048d9936 ZD |
1098 | /* It is unlikely that such large phi node would be redundant. */ |
1099 | if (PHI_NUM_ARGS (phi) > 16) | |
6de9cd9a DN |
1100 | return; |
1101 | ||
048d9936 | 1102 | for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++) |
6de9cd9a | 1103 | { |
048d9936 ZD |
1104 | def = PHI_ARG_DEF (phi, i); |
1105 | ||
1106 | if (TREE_CODE (def) == SSA_NAME) | |
1107 | { | |
1108 | def = get_eq_name (eq_to, def); | |
1109 | if (def == res) | |
1110 | continue; | |
1111 | } | |
1112 | ||
1113 | if (val | |
1114 | && !operand_equal_p (val, def, 0)) | |
6de9cd9a DN |
1115 | return; |
1116 | ||
048d9936 | 1117 | val = def; |
6de9cd9a | 1118 | } |
6de9cd9a | 1119 | |
048d9936 ZD |
1120 | /* At least one of the arguments should not be equal to the result, or |
1121 | something strange is happening. */ | |
1e128c5f | 1122 | gcc_assert (val); |
048d9936 ZD |
1123 | |
1124 | if (get_eq_name (eq_to, res) == val) | |
1125 | return; | |
1126 | ||
1127 | if (!may_propagate_copy (res, val)) | |
1128 | return; | |
1129 | ||
1130 | eq_to[ver] = val; | |
1131 | ||
1132 | df = get_immediate_uses (SSA_NAME_DEF_STMT (res)); | |
6de9cd9a DN |
1133 | n = num_immediate_uses (df); |
1134 | ||
1135 | for (i = 0; i < n; i++) | |
1136 | { | |
1137 | stmt = immediate_use (df, i); | |
1138 | ||
048d9936 ZD |
1139 | if (TREE_CODE (stmt) == PHI_NODE) |
1140 | check_phi_redundancy (stmt, eq_to); | |
6de9cd9a DN |
1141 | } |
1142 | } | |
1143 | ||
1144 | /* Removes redundant phi nodes. | |
1145 | ||
1146 | A redundant PHI node is a PHI node where all of its PHI arguments | |
1147 | are the same value, excluding any PHI arguments which are the same | |
1148 | as the PHI result. | |
1149 | ||
1150 | A redundant PHI node is effectively a copy, so we forward copy propagate | |
1151 | which removes all uses of the destination of the PHI node then | |
1152 | finally we delete the redundant PHI node. | |
1153 | ||
1154 | Note that if we can not copy propagate the PHI node, then the PHI | |
1155 | will not be removed. Thus we do not have to worry about dependencies | |
1156 | between PHIs and the problems serializing PHIs into copies creates. | |
1157 | ||
1158 | The most important effect of this pass is to remove degenerate PHI | |
1159 | nodes created by removing unreachable code. */ | |
1160 | ||
c66b6c66 | 1161 | void |
6de9cd9a DN |
1162 | kill_redundant_phi_nodes (void) |
1163 | { | |
95a3742c | 1164 | tree *eq_to; |
048d9936 | 1165 | unsigned i, old_num_ssa_names; |
6de9cd9a | 1166 | basic_block bb; |
048d9936 ZD |
1167 | tree phi, var, repl, stmt; |
1168 | ||
1169 | /* The EQ_TO[VER] holds the value by that the ssa name VER should be | |
1170 | replaced. If EQ_TO[VER] is ssa name and it is decided to replace it by | |
1171 | other value, it may be necessary to follow the chain till the final value. | |
1172 | We perform path shortening (replacing the entries of the EQ_TO array with | |
1173 | heads of these chains) whenever we access the field to prevent quadratic | |
1174 | complexity (probably would not occur in practice anyway, but let us play | |
1175 | it safe). */ | |
95a3742c | 1176 | eq_to = xcalloc (num_ssa_names, sizeof (tree)); |
6de9cd9a DN |
1177 | |
1178 | /* We have had cases where computing immediate uses takes a | |
1179 | significant amount of compile time. If we run into such | |
1180 | problems here, we may want to only compute immediate uses for | |
1181 | a subset of all the SSA_NAMEs instead of computing it for | |
1182 | all of the SSA_NAMEs. */ | |
1183 | compute_immediate_uses (TDFA_USE_OPS | TDFA_USE_VOPS, NULL); | |
048d9936 | 1184 | old_num_ssa_names = num_ssa_names; |
6de9cd9a DN |
1185 | |
1186 | FOR_EACH_BB (bb) | |
1187 | { | |
048d9936 | 1188 | for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi)) |
6de9cd9a DN |
1189 | { |
1190 | var = PHI_RESULT (phi); | |
048d9936 | 1191 | check_phi_redundancy (phi, eq_to); |
6de9cd9a DN |
1192 | } |
1193 | } | |
1194 | ||
1195 | /* Now propagate the values. */ | |
048d9936 ZD |
1196 | for (i = 0; i < old_num_ssa_names; i++) |
1197 | { | |
1198 | if (!ssa_name (i)) | |
1199 | continue; | |
1200 | ||
1201 | repl = get_eq_name (eq_to, ssa_name (i)); | |
1202 | if (repl != ssa_name (i)) | |
1203 | replace_immediate_uses (ssa_name (i), repl); | |
1204 | } | |
6de9cd9a DN |
1205 | |
1206 | /* And remove the dead phis. */ | |
048d9936 ZD |
1207 | for (i = 0; i < old_num_ssa_names; i++) |
1208 | { | |
1209 | if (!ssa_name (i)) | |
1210 | continue; | |
1211 | ||
1212 | repl = get_eq_name (eq_to, ssa_name (i)); | |
1213 | if (repl != ssa_name (i)) | |
1214 | { | |
1215 | stmt = SSA_NAME_DEF_STMT (ssa_name (i)); | |
1216 | remove_phi_node (stmt, NULL_TREE, bb_for_stmt (stmt)); | |
1217 | } | |
1218 | } | |
6de9cd9a DN |
1219 | |
1220 | free_df (); | |
1221 | free (eq_to); | |
6de9cd9a DN |
1222 | } |
1223 | ||
1224 | struct tree_opt_pass pass_redundant_phi = | |
1225 | { | |
1226 | "redphi", /* name */ | |
1227 | NULL, /* gate */ | |
1228 | kill_redundant_phi_nodes, /* execute */ | |
1229 | NULL, /* sub */ | |
1230 | NULL, /* next */ | |
1231 | 0, /* static_pass_number */ | |
1232 | 0, /* tv_id */ | |
c1b763fa | 1233 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ |
6de9cd9a DN |
1234 | 0, /* properties_provided */ |
1235 | 0, /* properties_destroyed */ | |
1236 | 0, /* todo_flags_start */ | |
1237 | TODO_dump_func | TODO_rename_vars | |
9f8628ba PB |
1238 | | TODO_ggc_collect | TODO_verify_ssa, /* todo_flags_finish */ |
1239 | 0 /* letter */ | |
6de9cd9a DN |
1240 | }; |
1241 | \f | |
1242 | /* Emit warnings for uninitialized variables. This is done in two passes. | |
1243 | ||
1244 | The first pass notices real uses of SSA names with default definitions. | |
1245 | Such uses are unconditionally uninitialized, and we can be certain that | |
1246 | such a use is a mistake. This pass is run before most optimizations, | |
1247 | so that we catch as many as we can. | |
1248 | ||
1249 | The second pass follows PHI nodes to find uses that are potentially | |
1250 | uninitialized. In this case we can't necessarily prove that the use | |
1251 | is really uninitialized. This pass is run after most optimizations, | |
1252 | so that we thread as many jumps and possible, and delete as much dead | |
1253 | code as possible, in order to reduce false positives. We also look | |
1254 | again for plain uninitialized variables, since optimization may have | |
1255 | changed conditionally uninitialized to unconditionally uninitialized. */ | |
1256 | ||
1257 | /* Emit a warning for T, an SSA_NAME, being uninitialized. The exact | |
1258 | warning text is in MSGID and LOCUS may contain a location or be null. */ | |
1259 | ||
1260 | static void | |
1261 | warn_uninit (tree t, const char *msgid, location_t *locus) | |
1262 | { | |
1263 | tree var = SSA_NAME_VAR (t); | |
1264 | tree def = SSA_NAME_DEF_STMT (t); | |
1265 | ||
1266 | /* Default uses (indicated by an empty definition statement), | |
1267 | are uninitialized. */ | |
1268 | if (!IS_EMPTY_STMT (def)) | |
1269 | return; | |
1270 | ||
1271 | /* Except for PARMs of course, which are always initialized. */ | |
1272 | if (TREE_CODE (var) == PARM_DECL) | |
1273 | return; | |
1274 | ||
1275 | /* Hard register variables get their initial value from the ether. */ | |
e670d9e4 | 1276 | if (TREE_CODE (var) == VAR_DECL && DECL_HARD_REGISTER (var)) |
6de9cd9a DN |
1277 | return; |
1278 | ||
1279 | /* TREE_NO_WARNING either means we already warned, or the front end | |
1280 | wishes to suppress the warning. */ | |
1281 | if (TREE_NO_WARNING (var)) | |
1282 | return; | |
1283 | ||
1284 | if (!locus) | |
1285 | locus = &DECL_SOURCE_LOCATION (var); | |
1286 | warning (msgid, locus, var); | |
1287 | TREE_NO_WARNING (var) = 1; | |
1288 | } | |
1289 | ||
1290 | /* Called via walk_tree, look for SSA_NAMEs that have empty definitions | |
1291 | and warn about them. */ | |
1292 | ||
1293 | static tree | |
1294 | warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data) | |
1295 | { | |
1296 | location_t *locus = data; | |
1297 | tree t = *tp; | |
1298 | ||
1299 | /* We only do data flow with SSA_NAMEs, so that's all we can warn about. */ | |
1300 | if (TREE_CODE (t) == SSA_NAME) | |
1301 | { | |
1302 | warn_uninit (t, "%H'%D' is used uninitialized in this function", locus); | |
1303 | *walk_subtrees = 0; | |
1304 | } | |
6615c446 | 1305 | else if (IS_TYPE_OR_DECL_P (t)) |
6de9cd9a DN |
1306 | *walk_subtrees = 0; |
1307 | ||
1308 | return NULL_TREE; | |
1309 | } | |
1310 | ||
1311 | /* Look for inputs to PHI that are SSA_NAMEs that have empty definitions | |
1312 | and warn about them. */ | |
1313 | ||
1314 | static void | |
1315 | warn_uninitialized_phi (tree phi) | |
1316 | { | |
1317 | int i, n = PHI_NUM_ARGS (phi); | |
1318 | ||
1319 | /* Don't look at memory tags. */ | |
1320 | if (!is_gimple_reg (PHI_RESULT (phi))) | |
1321 | return; | |
1322 | ||
1323 | for (i = 0; i < n; ++i) | |
1324 | { | |
1325 | tree op = PHI_ARG_DEF (phi, i); | |
1326 | if (TREE_CODE (op) == SSA_NAME) | |
1327 | warn_uninit (op, "%H'%D' may be used uninitialized in this function", | |
1328 | NULL); | |
1329 | } | |
1330 | } | |
1331 | ||
1332 | static void | |
1333 | execute_early_warn_uninitialized (void) | |
1334 | { | |
1335 | block_stmt_iterator bsi; | |
1336 | basic_block bb; | |
1337 | ||
1338 | FOR_EACH_BB (bb) | |
1339 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
1340 | walk_tree (bsi_stmt_ptr (bsi), warn_uninitialized_var, | |
1341 | EXPR_LOCUS (bsi_stmt (bsi)), NULL); | |
1342 | } | |
1343 | ||
1344 | static void | |
1345 | execute_late_warn_uninitialized (void) | |
1346 | { | |
1347 | basic_block bb; | |
1348 | tree phi; | |
1349 | ||
1350 | /* Re-do the plain uninitialized variable check, as optimization may have | |
1351 | straightened control flow. Do this first so that we don't accidentally | |
1352 | get a "may be" warning when we'd have seen an "is" warning later. */ | |
1353 | execute_early_warn_uninitialized (); | |
1354 | ||
1355 | FOR_EACH_BB (bb) | |
17192884 | 1356 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
6de9cd9a DN |
1357 | warn_uninitialized_phi (phi); |
1358 | } | |
1359 | ||
1360 | static bool | |
1361 | gate_warn_uninitialized (void) | |
1362 | { | |
1363 | return warn_uninitialized != 0; | |
1364 | } | |
1365 | ||
1366 | struct tree_opt_pass pass_early_warn_uninitialized = | |
1367 | { | |
1368 | NULL, /* name */ | |
1369 | gate_warn_uninitialized, /* gate */ | |
1370 | execute_early_warn_uninitialized, /* execute */ | |
1371 | NULL, /* sub */ | |
1372 | NULL, /* next */ | |
1373 | 0, /* static_pass_number */ | |
1374 | 0, /* tv_id */ | |
1375 | PROP_ssa, /* properties_required */ | |
1376 | 0, /* properties_provided */ | |
1377 | 0, /* properties_destroyed */ | |
1378 | 0, /* todo_flags_start */ | |
9f8628ba PB |
1379 | 0, /* todo_flags_finish */ |
1380 | 0 /* letter */ | |
6de9cd9a DN |
1381 | }; |
1382 | ||
1383 | struct tree_opt_pass pass_late_warn_uninitialized = | |
1384 | { | |
1385 | NULL, /* name */ | |
1386 | gate_warn_uninitialized, /* gate */ | |
1387 | execute_late_warn_uninitialized, /* execute */ | |
1388 | NULL, /* sub */ | |
1389 | NULL, /* next */ | |
1390 | 0, /* static_pass_number */ | |
1391 | 0, /* tv_id */ | |
1392 | PROP_ssa, /* properties_required */ | |
1393 | 0, /* properties_provided */ | |
1394 | 0, /* properties_destroyed */ | |
1395 | 0, /* todo_flags_start */ | |
9f8628ba PB |
1396 | 0, /* todo_flags_finish */ |
1397 | 0 /* letter */ | |
6de9cd9a | 1398 | }; |