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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" | |
44 | #include "tree-alias-common.h" | |
45 | #include "hashtab.h" | |
46 | #include "tree-dump.h" | |
47 | #include "tree-pass.h" | |
48 | ||
49 | ||
50 | /* Remove edge E and remove the corresponding arguments from the PHI nodes | |
51 | in E's destination block. */ | |
52 | ||
53 | void | |
54 | ssa_remove_edge (edge e) | |
55 | { | |
56 | tree phi, next; | |
57 | ||
58 | /* Remove the appropriate PHI arguments in E's destination block. */ | |
59 | for (phi = phi_nodes (e->dest); phi; phi = next) | |
60 | { | |
17192884 | 61 | next = PHI_CHAIN (phi); |
6de9cd9a DN |
62 | remove_phi_arg (phi, e->src); |
63 | } | |
64 | ||
65 | remove_edge (e); | |
66 | } | |
67 | ||
f6144c34 BE |
68 | /* Remove the corresponding arguments from the PHI nodes in E's |
69 | destination block and redirect it to DEST. Return redirected edge. | |
6de9cd9a DN |
70 | The list of removed arguments is stored in PENDING_STMT (e). */ |
71 | ||
72 | edge | |
73 | ssa_redirect_edge (edge e, basic_block dest) | |
74 | { | |
75 | tree phi, next; | |
76 | tree list = NULL, *last = &list; | |
77 | tree src, dst, node; | |
78 | int i; | |
79 | ||
80 | /* Remove the appropriate PHI arguments in E's destination block. */ | |
81 | for (phi = phi_nodes (e->dest); phi; phi = next) | |
82 | { | |
17192884 | 83 | next = PHI_CHAIN (phi); |
6de9cd9a DN |
84 | |
85 | i = phi_arg_from_edge (phi, e); | |
86 | if (i < 0) | |
87 | continue; | |
88 | ||
89 | src = PHI_ARG_DEF (phi, i); | |
90 | dst = PHI_RESULT (phi); | |
91 | node = build_tree_list (dst, src); | |
92 | *last = node; | |
93 | last = &TREE_CHAIN (node); | |
94 | ||
95 | remove_phi_arg_num (phi, i); | |
96 | } | |
97 | ||
98 | e = redirect_edge_succ_nodup (e, dest); | |
99 | PENDING_STMT (e) = list; | |
100 | ||
101 | return e; | |
102 | } | |
103 | ||
104 | ||
53b4bf74 | 105 | /* Return true if SSA_NAME is malformed and mark it visited. |
6de9cd9a | 106 | |
53b4bf74 DN |
107 | IS_VIRTUAL is true if this SSA_NAME was found inside a virtual |
108 | operand. */ | |
6de9cd9a DN |
109 | |
110 | static bool | |
53b4bf74 | 111 | verify_ssa_name (tree ssa_name, bool is_virtual) |
6de9cd9a | 112 | { |
53b4bf74 | 113 | TREE_VISITED (ssa_name) = 1; |
6de9cd9a DN |
114 | |
115 | if (TREE_CODE (ssa_name) != SSA_NAME) | |
116 | { | |
117 | error ("Expected an SSA_NAME object"); | |
53b4bf74 | 118 | return true; |
6de9cd9a DN |
119 | } |
120 | ||
bbc630f5 DN |
121 | if (TREE_TYPE (ssa_name) != TREE_TYPE (SSA_NAME_VAR (ssa_name))) |
122 | { | |
123 | error ("Type mismatch between an SSA_NAME and its symbol."); | |
124 | return true; | |
125 | } | |
126 | ||
53b4bf74 DN |
127 | if (SSA_NAME_IN_FREE_LIST (ssa_name)) |
128 | { | |
129 | error ("Found an SSA_NAME that had been released into the free pool"); | |
130 | return true; | |
131 | } | |
132 | ||
133 | if (is_virtual && is_gimple_reg (ssa_name)) | |
134 | { | |
135 | error ("Found a virtual definition for a GIMPLE register"); | |
136 | return true; | |
137 | } | |
138 | ||
139 | if (!is_virtual && !is_gimple_reg (ssa_name)) | |
140 | { | |
141 | error ("Found a real definition for a non-register"); | |
142 | return true; | |
143 | } | |
144 | ||
145 | return false; | |
146 | } | |
147 | ||
148 | ||
149 | /* Return true if the definition of SSA_NAME at block BB is malformed. | |
150 | ||
151 | STMT is the statement where SSA_NAME is created. | |
152 | ||
153 | DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME | |
154 | version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set, | |
155 | it means that the block in that array slot contains the | |
156 | definition of SSA_NAME. | |
157 | ||
158 | IS_VIRTUAL is true if SSA_NAME is created by a V_MAY_DEF or a | |
159 | V_MUST_DEF. */ | |
160 | ||
161 | static bool | |
162 | verify_def (basic_block bb, basic_block *definition_block, tree ssa_name, | |
163 | tree stmt, bool is_virtual) | |
164 | { | |
165 | if (verify_ssa_name (ssa_name, is_virtual)) | |
166 | goto err; | |
167 | ||
6de9cd9a DN |
168 | if (definition_block[SSA_NAME_VERSION (ssa_name)]) |
169 | { | |
170 | error ("SSA_NAME created in two different blocks %i and %i", | |
171 | definition_block[SSA_NAME_VERSION (ssa_name)]->index, bb->index); | |
53b4bf74 | 172 | goto err; |
6de9cd9a DN |
173 | } |
174 | ||
175 | definition_block[SSA_NAME_VERSION (ssa_name)] = bb; | |
176 | ||
177 | if (SSA_NAME_DEF_STMT (ssa_name) != stmt) | |
178 | { | |
179 | error ("SSA_NAME_DEF_STMT is wrong"); | |
6de9cd9a DN |
180 | fprintf (stderr, "Expected definition statement:\n"); |
181 | debug_generic_stmt (SSA_NAME_DEF_STMT (ssa_name)); | |
182 | fprintf (stderr, "\nActual definition statement:\n"); | |
183 | debug_generic_stmt (stmt); | |
53b4bf74 | 184 | goto err; |
6de9cd9a DN |
185 | } |
186 | ||
53b4bf74 DN |
187 | return false; |
188 | ||
189 | err: | |
190 | fprintf (stderr, "while verifying SSA_NAME "); | |
191 | print_generic_expr (stderr, ssa_name, 0); | |
192 | fprintf (stderr, " in statement\n"); | |
193 | debug_generic_stmt (stmt); | |
194 | ||
195 | return true; | |
6de9cd9a DN |
196 | } |
197 | ||
198 | ||
199 | /* Return true if the use of SSA_NAME at statement STMT in block BB is | |
200 | malformed. | |
201 | ||
202 | DEF_BB is the block where SSA_NAME was found to be created. | |
203 | ||
204 | IDOM contains immediate dominator information for the flowgraph. | |
205 | ||
206 | CHECK_ABNORMAL is true if the caller wants to check whether this use | |
207 | is flowing through an abnormal edge (only used when checking PHI | |
53b4bf74 DN |
208 | arguments). |
209 | ||
210 | IS_VIRTUAL is true if SSA_NAME is created by a V_MAY_DEF or a | |
211 | V_MUST_DEF. */ | |
6de9cd9a DN |
212 | |
213 | static bool | |
214 | verify_use (basic_block bb, basic_block def_bb, tree ssa_name, | |
53b4bf74 | 215 | tree stmt, bool check_abnormal, bool is_virtual) |
6de9cd9a DN |
216 | { |
217 | bool err = false; | |
218 | ||
53b4bf74 DN |
219 | err = verify_ssa_name (ssa_name, is_virtual); |
220 | ||
221 | if (IS_EMPTY_STMT (SSA_NAME_DEF_STMT (ssa_name)) | |
222 | && var_ann (SSA_NAME_VAR (ssa_name))->default_def == ssa_name) | |
223 | ; /* Default definitions have empty statements. Nothing to do. */ | |
6de9cd9a DN |
224 | else if (!def_bb) |
225 | { | |
226 | error ("Missing definition"); | |
227 | err = true; | |
228 | } | |
229 | else if (bb != def_bb | |
230 | && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) | |
231 | { | |
232 | error ("Definition in block %i does not dominate use in block %i", | |
233 | def_bb->index, bb->index); | |
234 | err = true; | |
235 | } | |
236 | ||
237 | if (check_abnormal | |
238 | && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssa_name)) | |
239 | { | |
240 | error ("SSA_NAME_OCCURS_IN_ABNORMAL_PHI should be set"); | |
241 | err = true; | |
242 | } | |
243 | ||
244 | if (err) | |
245 | { | |
246 | fprintf (stderr, "for SSA_NAME: "); | |
53b4bf74 | 247 | debug_generic_expr (ssa_name); |
6de9cd9a DN |
248 | fprintf (stderr, "in statement:\n"); |
249 | debug_generic_stmt (stmt); | |
250 | } | |
251 | ||
252 | return err; | |
253 | } | |
254 | ||
255 | ||
256 | /* Return true if any of the arguments for PHI node PHI at block BB is | |
257 | malformed. | |
258 | ||
259 | IDOM contains immediate dominator information for the flowgraph. | |
260 | ||
261 | DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME version | |
262 | numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set, it means that the | |
263 | block in that array slot contains the definition of SSA_NAME. */ | |
264 | ||
265 | static bool | |
266 | verify_phi_args (tree phi, basic_block bb, basic_block *definition_block) | |
267 | { | |
268 | edge e; | |
269 | bool err = false; | |
270 | int i, phi_num_args = PHI_NUM_ARGS (phi); | |
271 | ||
272 | /* Mark all the incoming edges. */ | |
273 | for (e = bb->pred; e; e = e->pred_next) | |
274 | e->aux = (void *) 1; | |
275 | ||
276 | for (i = 0; i < phi_num_args; i++) | |
277 | { | |
278 | tree op = PHI_ARG_DEF (phi, i); | |
279 | ||
280 | e = PHI_ARG_EDGE (phi, i); | |
281 | ||
282 | if (TREE_CODE (op) == SSA_NAME) | |
53b4bf74 DN |
283 | err = verify_use (e->src, definition_block[SSA_NAME_VERSION (op)], op, |
284 | phi, e->flags & EDGE_ABNORMAL, | |
285 | !is_gimple_reg (PHI_RESULT (phi))); | |
6de9cd9a DN |
286 | |
287 | if (e->dest != bb) | |
288 | { | |
289 | error ("Wrong edge %d->%d for PHI argument\n", | |
290 | e->src->index, e->dest->index, bb->index); | |
291 | err = true; | |
292 | } | |
293 | ||
294 | if (e->aux == (void *) 0) | |
295 | { | |
296 | error ("PHI argument flowing through dead edge %d->%d\n", | |
297 | e->src->index, e->dest->index); | |
298 | err = true; | |
299 | } | |
300 | ||
301 | if (e->aux == (void *) 2) | |
302 | { | |
303 | error ("PHI argument duplicated for edge %d->%d\n", e->src->index, | |
304 | e->dest->index); | |
305 | err = true; | |
306 | } | |
307 | ||
308 | if (err) | |
309 | { | |
310 | fprintf (stderr, "PHI argument\n"); | |
311 | debug_generic_stmt (op); | |
53b4bf74 | 312 | goto error; |
6de9cd9a DN |
313 | } |
314 | ||
315 | e->aux = (void *) 2; | |
316 | } | |
317 | ||
318 | for (e = bb->pred; e; e = e->pred_next) | |
319 | { | |
320 | if (e->aux != (void *) 2) | |
321 | { | |
322 | error ("No argument flowing through edge %d->%d\n", e->src->index, | |
323 | e->dest->index); | |
324 | err = true; | |
53b4bf74 | 325 | goto error; |
6de9cd9a DN |
326 | } |
327 | e->aux = (void *) 0; | |
328 | } | |
329 | ||
53b4bf74 | 330 | error: |
6de9cd9a DN |
331 | if (err) |
332 | { | |
333 | fprintf (stderr, "for PHI node\n"); | |
334 | debug_generic_stmt (phi); | |
335 | } | |
336 | ||
337 | ||
338 | return err; | |
339 | } | |
340 | ||
341 | ||
53b4bf74 DN |
342 | static void |
343 | verify_flow_insensitive_alias_info (void) | |
344 | { | |
345 | size_t i; | |
346 | tree var; | |
347 | bitmap visited = BITMAP_XMALLOC (); | |
348 | ||
349 | for (i = 0; i < num_referenced_vars; i++) | |
350 | { | |
852c7b12 | 351 | size_t j; |
53b4bf74 | 352 | var_ann_t ann; |
852c7b12 | 353 | varray_type may_aliases; |
53b4bf74 DN |
354 | |
355 | var = referenced_var (i); | |
356 | ann = var_ann (var); | |
852c7b12 | 357 | may_aliases = ann->may_aliases; |
53b4bf74 | 358 | |
852c7b12 | 359 | for (j = 0; may_aliases && j < VARRAY_ACTIVE_SIZE (may_aliases); j++) |
53b4bf74 | 360 | { |
852c7b12 | 361 | tree alias = VARRAY_TREE (may_aliases, j); |
53b4bf74 | 362 | |
852c7b12 | 363 | bitmap_set_bit (visited, var_ann (alias)->uid); |
53b4bf74 | 364 | |
852c7b12 DN |
365 | if (!may_be_aliased (alias)) |
366 | { | |
367 | error ("Non-addressable variable inside an alias set."); | |
368 | debug_variable (alias); | |
369 | goto err; | |
53b4bf74 DN |
370 | } |
371 | } | |
372 | } | |
373 | ||
374 | for (i = 0; i < num_referenced_vars; i++) | |
375 | { | |
376 | var_ann_t ann; | |
377 | ||
378 | var = referenced_var (i); | |
379 | ann = var_ann (var); | |
380 | ||
381 | if (ann->mem_tag_kind == NOT_A_TAG | |
382 | && ann->is_alias_tag | |
383 | && !bitmap_bit_p (visited, ann->uid)) | |
384 | { | |
385 | error ("Addressable variable that is an alias tag but is not in any alias set."); | |
386 | goto err; | |
387 | } | |
388 | } | |
389 | ||
390 | BITMAP_XFREE (visited); | |
391 | return; | |
392 | ||
393 | err: | |
394 | debug_variable (var); | |
395 | internal_error ("verify_flow_insensitive_alias_info failed."); | |
396 | } | |
397 | ||
398 | ||
399 | static void | |
400 | verify_flow_sensitive_alias_info (void) | |
401 | { | |
402 | size_t i; | |
403 | tree ptr; | |
404 | ||
405 | for (i = 1; i < num_ssa_names; i++) | |
406 | { | |
407 | var_ann_t ann; | |
408 | struct ptr_info_def *pi; | |
409 | ||
410 | ptr = ssa_name (i); | |
411 | ann = var_ann (SSA_NAME_VAR (ptr)); | |
412 | pi = SSA_NAME_PTR_INFO (ptr); | |
413 | ||
414 | /* We only care for pointers that are actually referenced in the | |
415 | program. */ | |
416 | if (!TREE_VISITED (ptr) || !POINTER_TYPE_P (TREE_TYPE (ptr))) | |
417 | continue; | |
418 | ||
419 | /* RESULT_DECL is special. If it's a GIMPLE register, then it | |
420 | is only written-to only once in the return statement. | |
421 | Otherwise, aggregate RESULT_DECLs may be written-to more than | |
422 | once in virtual operands. */ | |
423 | if (TREE_CODE (SSA_NAME_VAR (ptr)) == RESULT_DECL | |
424 | && is_gimple_reg (ptr)) | |
425 | continue; | |
426 | ||
427 | if (pi == NULL) | |
428 | continue; | |
429 | ||
430 | if (pi->is_dereferenced && !pi->name_mem_tag && !ann->type_mem_tag) | |
431 | { | |
432 | error ("Dereferenced pointers should have a name or a type tag"); | |
433 | goto err; | |
434 | } | |
435 | ||
53b4bf74 DN |
436 | if (pi->name_mem_tag |
437 | && !pi->pt_malloc | |
438 | && (pi->pt_vars == NULL | |
439 | || bitmap_first_set_bit (pi->pt_vars) < 0)) | |
440 | { | |
441 | error ("Pointers with a memory tag, should have points-to sets or point to malloc"); | |
442 | goto err; | |
443 | } | |
444 | ||
445 | if (pi->value_escapes_p | |
446 | && pi->name_mem_tag | |
447 | && !is_call_clobbered (pi->name_mem_tag)) | |
448 | { | |
449 | error ("Pointer escapes but its name tag is not call-clobbered."); | |
450 | goto err; | |
451 | } | |
452 | ||
453 | if (pi->name_mem_tag && pi->pt_vars) | |
454 | { | |
455 | size_t j; | |
456 | ||
457 | for (j = i + 1; j < num_ssa_names; j++) | |
458 | { | |
459 | tree ptr2 = ssa_name (j); | |
460 | struct ptr_info_def *pi2 = SSA_NAME_PTR_INFO (ptr2); | |
461 | ||
118a8d02 | 462 | if (!TREE_VISITED (ptr2) || !POINTER_TYPE_P (TREE_TYPE (ptr2))) |
53b4bf74 DN |
463 | continue; |
464 | ||
465 | if (pi2 | |
466 | && pi2->name_mem_tag | |
467 | && pi2->pt_vars | |
468 | && bitmap_first_set_bit (pi2->pt_vars) >= 0 | |
469 | && pi->name_mem_tag != pi2->name_mem_tag | |
470 | && bitmap_equal_p (pi->pt_vars, pi2->pt_vars)) | |
471 | { | |
472 | error ("Two pointers with different name tags and identical points-to sets"); | |
473 | debug_variable (ptr2); | |
474 | goto err; | |
475 | } | |
476 | } | |
477 | } | |
478 | } | |
479 | ||
480 | return; | |
481 | ||
482 | err: | |
483 | debug_variable (ptr); | |
484 | internal_error ("verify_flow_sensitive_alias_info failed."); | |
485 | } | |
486 | ||
487 | ||
488 | /* Verify the consistency of aliasing information. */ | |
489 | ||
490 | static void | |
491 | verify_alias_info (void) | |
492 | { | |
c1b763fa DN |
493 | verify_flow_sensitive_alias_info (); |
494 | verify_flow_insensitive_alias_info (); | |
53b4bf74 DN |
495 | } |
496 | ||
497 | ||
6de9cd9a DN |
498 | /* Verify common invariants in the SSA web. |
499 | TODO: verify the variable annotations. */ | |
500 | ||
501 | void | |
502 | verify_ssa (void) | |
503 | { | |
53b4bf74 | 504 | size_t i; |
6de9cd9a | 505 | basic_block bb; |
95a3742c | 506 | basic_block *definition_block = xcalloc (num_ssa_names, sizeof (basic_block)); |
4c124b4c AM |
507 | ssa_op_iter iter; |
508 | tree op; | |
6de9cd9a DN |
509 | |
510 | timevar_push (TV_TREE_SSA_VERIFY); | |
511 | ||
53b4bf74 DN |
512 | /* Keep track of SSA names present in the IL. */ |
513 | for (i = 1; i < num_ssa_names; i++) | |
514 | TREE_VISITED (ssa_name (i)) = 0; | |
515 | ||
6de9cd9a DN |
516 | calculate_dominance_info (CDI_DOMINATORS); |
517 | ||
518 | /* Verify and register all the SSA_NAME definitions found in the | |
519 | function. */ | |
520 | FOR_EACH_BB (bb) | |
521 | { | |
522 | tree phi; | |
523 | block_stmt_iterator bsi; | |
524 | ||
17192884 | 525 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
53b4bf74 DN |
526 | if (verify_def (bb, definition_block, PHI_RESULT (phi), phi, |
527 | !is_gimple_reg (PHI_RESULT (phi)))) | |
528 | goto err; | |
6de9cd9a DN |
529 | |
530 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
531 | { | |
532 | tree stmt; | |
6de9cd9a DN |
533 | |
534 | stmt = bsi_stmt (bsi); | |
6de9cd9a DN |
535 | get_stmt_operands (stmt); |
536 | ||
4c124b4c AM |
537 | if (stmt_ann (stmt)->makes_aliased_stores |
538 | && NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt)) == 0) | |
53b4bf74 DN |
539 | { |
540 | error ("Statement makes aliased stores, but has no V_MAY_DEFS"); | |
541 | debug_generic_stmt (stmt); | |
542 | goto err; | |
543 | } | |
a32b97a2 | 544 | |
4c124b4c | 545 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_VIRTUAL_DEFS) |
6de9cd9a | 546 | { |
53b4bf74 DN |
547 | if (verify_def (bb, definition_block, op, stmt, true)) |
548 | goto err; | |
6de9cd9a | 549 | } |
a32b97a2 | 550 | |
4c124b4c | 551 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF) |
a32b97a2 | 552 | { |
53b4bf74 DN |
553 | if (verify_def (bb, definition_block, op, stmt, false)) |
554 | goto err; | |
6de9cd9a DN |
555 | } |
556 | } | |
557 | } | |
558 | ||
559 | ||
560 | /* Now verify all the uses and make sure they agree with the definitions | |
561 | found in the previous pass. */ | |
562 | FOR_EACH_BB (bb) | |
563 | { | |
564 | edge e; | |
565 | tree phi; | |
566 | block_stmt_iterator bsi; | |
567 | ||
568 | /* Make sure that all edges have a clear 'aux' field. */ | |
569 | for (e = bb->pred; e; e = e->pred_next) | |
570 | { | |
571 | if (e->aux) | |
572 | { | |
573 | error ("AUX pointer initialized for edge %d->%d\n", e->src->index, | |
574 | e->dest->index); | |
53b4bf74 | 575 | goto err; |
6de9cd9a DN |
576 | } |
577 | } | |
578 | ||
579 | /* Verify the arguments for every PHI node in the block. */ | |
17192884 | 580 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
53b4bf74 DN |
581 | if (verify_phi_args (phi, bb, definition_block)) |
582 | goto err; | |
6de9cd9a | 583 | |
53b4bf74 | 584 | /* Now verify all the uses and vuses in every statement of the block. */ |
6de9cd9a DN |
585 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) |
586 | { | |
587 | tree stmt = bsi_stmt (bsi); | |
6de9cd9a | 588 | |
4c124b4c | 589 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_VIRTUAL_USES) |
6de9cd9a | 590 | { |
53b4bf74 DN |
591 | if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)], |
592 | op, stmt, false, true)) | |
593 | goto err; | |
6de9cd9a DN |
594 | } |
595 | ||
4c124b4c | 596 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE) |
6de9cd9a | 597 | { |
53b4bf74 DN |
598 | if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)], |
599 | op, stmt, false, false)) | |
600 | goto err; | |
6de9cd9a DN |
601 | } |
602 | } | |
603 | } | |
604 | ||
53b4bf74 DN |
605 | /* Finally, verify alias information. */ |
606 | verify_alias_info (); | |
6de9cd9a | 607 | |
53b4bf74 | 608 | free (definition_block); |
6de9cd9a | 609 | timevar_pop (TV_TREE_SSA_VERIFY); |
53b4bf74 | 610 | return; |
6de9cd9a | 611 | |
53b4bf74 DN |
612 | err: |
613 | internal_error ("verify_ssa failed."); | |
6de9cd9a DN |
614 | } |
615 | ||
616 | ||
6de9cd9a DN |
617 | /* Initialize global DFA and SSA structures. */ |
618 | ||
619 | void | |
620 | init_tree_ssa (void) | |
621 | { | |
622 | VARRAY_TREE_INIT (referenced_vars, 20, "referenced_vars"); | |
623 | call_clobbered_vars = BITMAP_XMALLOC (); | |
a6d02559 | 624 | addressable_vars = BITMAP_XMALLOC (); |
6de9cd9a DN |
625 | init_ssa_operands (); |
626 | init_ssanames (); | |
627 | init_phinodes (); | |
628 | global_var = NULL_TREE; | |
6de9cd9a DN |
629 | } |
630 | ||
631 | ||
632 | /* Deallocate memory associated with SSA data structures for FNDECL. */ | |
633 | ||
634 | void | |
635 | delete_tree_ssa (void) | |
636 | { | |
637 | size_t i; | |
638 | basic_block bb; | |
639 | block_stmt_iterator bsi; | |
640 | ||
641 | /* Remove annotations from every tree in the function. */ | |
642 | FOR_EACH_BB (bb) | |
643 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
80d8221e JH |
644 | { |
645 | tree stmt = bsi_stmt (bsi); | |
646 | release_defs (stmt); | |
647 | ggc_free (stmt->common.ann); | |
648 | stmt->common.ann = NULL; | |
649 | } | |
6de9cd9a DN |
650 | |
651 | /* Remove annotations from every referenced variable. */ | |
652 | if (referenced_vars) | |
653 | { | |
654 | for (i = 0; i < num_referenced_vars; i++) | |
80d8221e JH |
655 | { |
656 | tree var = referenced_var (i); | |
657 | ggc_free (var->common.ann); | |
658 | var->common.ann = NULL; | |
659 | } | |
6de9cd9a DN |
660 | referenced_vars = NULL; |
661 | } | |
662 | ||
663 | fini_ssanames (); | |
664 | fini_phinodes (); | |
665 | fini_ssa_operands (); | |
666 | ||
667 | global_var = NULL_TREE; | |
6b9bee8e | 668 | BITMAP_XFREE (call_clobbered_vars); |
6de9cd9a | 669 | call_clobbered_vars = NULL; |
a6d02559 DN |
670 | BITMAP_XFREE (addressable_vars); |
671 | addressable_vars = NULL; | |
6de9cd9a DN |
672 | } |
673 | ||
674 | ||
675 | /* Return true if EXPR is a useless type conversion, otherwise return | |
676 | false. */ | |
677 | ||
678 | bool | |
679 | tree_ssa_useless_type_conversion_1 (tree outer_type, tree inner_type) | |
680 | { | |
681 | /* If the inner and outer types are effectively the same, then | |
682 | strip the type conversion and enter the equivalence into | |
683 | the table. */ | |
684 | if (inner_type == outer_type | |
685 | || (lang_hooks.types_compatible_p (inner_type, outer_type))) | |
686 | return true; | |
687 | ||
688 | /* If both types are pointers and the outer type is a (void *), then | |
689 | the conversion is not necessary. The opposite is not true since | |
690 | that conversion would result in a loss of information if the | |
691 | equivalence was used. Consider an indirect function call where | |
692 | we need to know the exact type of the function to correctly | |
693 | implement the ABI. */ | |
694 | else if (POINTER_TYPE_P (inner_type) | |
695 | && POINTER_TYPE_P (outer_type) | |
696 | && TREE_CODE (TREE_TYPE (outer_type)) == VOID_TYPE) | |
697 | return true; | |
698 | ||
699 | /* Pointers and references are equivalent once we get to GENERIC, | |
700 | so strip conversions that just switch between them. */ | |
701 | else if (POINTER_TYPE_P (inner_type) | |
702 | && POINTER_TYPE_P (outer_type) | |
3facc4b6 AP |
703 | && lang_hooks.types_compatible_p (TREE_TYPE (inner_type), |
704 | TREE_TYPE (outer_type))) | |
6de9cd9a DN |
705 | return true; |
706 | ||
707 | /* If both the inner and outer types are integral types, then the | |
708 | conversion is not necessary if they have the same mode and | |
bc15d0ef JM |
709 | signedness and precision, and both or neither are boolean. Some |
710 | code assumes an invariant that boolean types stay boolean and do | |
711 | not become 1-bit bit-field types. Note that types with precision | |
712 | not using all bits of the mode (such as bit-field types in C) | |
713 | mean that testing of precision is necessary. */ | |
6de9cd9a DN |
714 | else if (INTEGRAL_TYPE_P (inner_type) |
715 | && INTEGRAL_TYPE_P (outer_type) | |
716 | && TYPE_MODE (inner_type) == TYPE_MODE (outer_type) | |
717 | && TYPE_UNSIGNED (inner_type) == TYPE_UNSIGNED (outer_type) | |
718 | && TYPE_PRECISION (inner_type) == TYPE_PRECISION (outer_type)) | |
bc15d0ef JM |
719 | { |
720 | bool first_boolean = (TREE_CODE (inner_type) == BOOLEAN_TYPE); | |
721 | bool second_boolean = (TREE_CODE (outer_type) == BOOLEAN_TYPE); | |
722 | if (first_boolean == second_boolean) | |
723 | return true; | |
724 | } | |
6de9cd9a DN |
725 | |
726 | /* Recurse for complex types. */ | |
727 | else if (TREE_CODE (inner_type) == COMPLEX_TYPE | |
728 | && TREE_CODE (outer_type) == COMPLEX_TYPE | |
729 | && tree_ssa_useless_type_conversion_1 (TREE_TYPE (outer_type), | |
730 | TREE_TYPE (inner_type))) | |
731 | return true; | |
732 | ||
733 | return false; | |
734 | } | |
735 | ||
736 | /* Return true if EXPR is a useless type conversion, otherwise return | |
737 | false. */ | |
738 | ||
739 | bool | |
740 | tree_ssa_useless_type_conversion (tree expr) | |
741 | { | |
742 | /* If we have an assignment that merely uses a NOP_EXPR to change | |
743 | the top of the RHS to the type of the LHS and the type conversion | |
744 | is "safe", then strip away the type conversion so that we can | |
745 | enter LHS = RHS into the const_and_copies table. */ | |
580d124f RK |
746 | if (TREE_CODE (expr) == NOP_EXPR || TREE_CODE (expr) == CONVERT_EXPR |
747 | || TREE_CODE (expr) == VIEW_CONVERT_EXPR | |
748 | || TREE_CODE (expr) == NON_LVALUE_EXPR) | |
6de9cd9a DN |
749 | return tree_ssa_useless_type_conversion_1 (TREE_TYPE (expr), |
750 | TREE_TYPE (TREE_OPERAND (expr, | |
751 | 0))); | |
752 | ||
753 | ||
754 | return false; | |
755 | } | |
756 | ||
757 | ||
758 | /* Internal helper for walk_use_def_chains. VAR, FN and DATA are as | |
53b4bf74 DN |
759 | described in walk_use_def_chains. |
760 | ||
761 | VISITED is a bitmap used to mark visited SSA_NAMEs to avoid | |
762 | infinite loops. | |
763 | ||
764 | IS_DFS is true if the caller wants to perform a depth-first search | |
765 | when visiting PHI nodes. A DFS will visit each PHI argument and | |
766 | call FN after each one. Otherwise, all the arguments are | |
767 | visited first and then FN is called with each of the visited | |
768 | arguments in a separate pass. */ | |
6de9cd9a DN |
769 | |
770 | static bool | |
771 | walk_use_def_chains_1 (tree var, walk_use_def_chains_fn fn, void *data, | |
53b4bf74 | 772 | bitmap visited, bool is_dfs) |
6de9cd9a DN |
773 | { |
774 | tree def_stmt; | |
775 | ||
776 | if (bitmap_bit_p (visited, SSA_NAME_VERSION (var))) | |
777 | return false; | |
778 | ||
779 | bitmap_set_bit (visited, SSA_NAME_VERSION (var)); | |
780 | ||
781 | def_stmt = SSA_NAME_DEF_STMT (var); | |
782 | ||
783 | if (TREE_CODE (def_stmt) != PHI_NODE) | |
784 | { | |
785 | /* If we reached the end of the use-def chain, call FN. */ | |
53b4bf74 | 786 | return fn (var, def_stmt, data); |
6de9cd9a DN |
787 | } |
788 | else | |
789 | { | |
790 | int i; | |
791 | ||
53b4bf74 DN |
792 | /* When doing a breadth-first search, call FN before following the |
793 | use-def links for each argument. */ | |
794 | if (!is_dfs) | |
795 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) | |
796 | if (fn (PHI_ARG_DEF (def_stmt, i), def_stmt, data)) | |
797 | return true; | |
798 | ||
799 | /* Follow use-def links out of each PHI argument. */ | |
6de9cd9a DN |
800 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) |
801 | { | |
802 | tree arg = PHI_ARG_DEF (def_stmt, i); | |
803 | if (TREE_CODE (arg) == SSA_NAME | |
53b4bf74 | 804 | && walk_use_def_chains_1 (arg, fn, data, visited, is_dfs)) |
6de9cd9a DN |
805 | return true; |
806 | } | |
53b4bf74 DN |
807 | |
808 | /* When doing a depth-first search, call FN after following the | |
809 | use-def links for each argument. */ | |
810 | if (is_dfs) | |
811 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) | |
812 | if (fn (PHI_ARG_DEF (def_stmt, i), def_stmt, data)) | |
813 | return true; | |
6de9cd9a | 814 | } |
53b4bf74 | 815 | |
6de9cd9a DN |
816 | return false; |
817 | } | |
818 | ||
819 | ||
820 | ||
53b4bf74 DN |
821 | /* Walk use-def chains starting at the SSA variable VAR. Call |
822 | function FN at each reaching definition found. FN takes three | |
823 | arguments: VAR, its defining statement (DEF_STMT) and a generic | |
824 | pointer to whatever state information that FN may want to maintain | |
825 | (DATA). FN is able to stop the walk by returning true, otherwise | |
826 | in order to continue the walk, FN should return false. | |
6de9cd9a DN |
827 | |
828 | Note, that if DEF_STMT is a PHI node, the semantics are slightly | |
53b4bf74 DN |
829 | different. The first argument to FN is no longer the original |
830 | variable VAR, but the PHI argument currently being examined. If FN | |
831 | wants to get at VAR, it should call PHI_RESULT (PHI). | |
832 | ||
833 | If IS_DFS is true, this function will: | |
6de9cd9a | 834 | |
53b4bf74 DN |
835 | 1- walk the use-def chains for all the PHI arguments, and, |
836 | 2- call (*FN) (ARG, PHI, DATA) on all the PHI arguments. | |
837 | ||
838 | If IS_DFS is false, the two steps above are done in reverse order | |
839 | (i.e., a breadth-first search). */ | |
6de9cd9a | 840 | |
6de9cd9a DN |
841 | |
842 | void | |
53b4bf74 DN |
843 | walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data, |
844 | bool is_dfs) | |
6de9cd9a DN |
845 | { |
846 | tree def_stmt; | |
847 | ||
848 | #if defined ENABLE_CHECKING | |
849 | if (TREE_CODE (var) != SSA_NAME) | |
850 | abort (); | |
851 | #endif | |
852 | ||
853 | def_stmt = SSA_NAME_DEF_STMT (var); | |
854 | ||
855 | /* We only need to recurse if the reaching definition comes from a PHI | |
856 | node. */ | |
857 | if (TREE_CODE (def_stmt) != PHI_NODE) | |
858 | (*fn) (var, def_stmt, data); | |
859 | else | |
860 | { | |
861 | bitmap visited = BITMAP_XMALLOC (); | |
53b4bf74 | 862 | walk_use_def_chains_1 (var, fn, data, visited, is_dfs); |
6de9cd9a DN |
863 | BITMAP_XFREE (visited); |
864 | } | |
865 | } | |
866 | ||
53b4bf74 | 867 | |
d7621d3c ZD |
868 | /* Replaces VAR with REPL in memory reference expression *X in |
869 | statement STMT. */ | |
870 | ||
871 | static void | |
872 | propagate_into_addr (tree stmt, tree var, tree *x, tree repl) | |
873 | { | |
874 | tree new_var, ass_stmt, addr_var; | |
875 | basic_block bb; | |
876 | block_stmt_iterator bsi; | |
877 | ||
878 | /* There is nothing special to handle in the other cases. */ | |
879 | if (TREE_CODE (repl) != ADDR_EXPR) | |
880 | return; | |
881 | addr_var = TREE_OPERAND (repl, 0); | |
882 | ||
0705d602 RK |
883 | while (handled_component_p (*x) |
884 | || TREE_CODE (*x) == REALPART_EXPR | |
885 | || TREE_CODE (*x) == IMAGPART_EXPR) | |
d7621d3c ZD |
886 | x = &TREE_OPERAND (*x, 0); |
887 | ||
888 | if (TREE_CODE (*x) != INDIRECT_REF | |
889 | || TREE_OPERAND (*x, 0) != var) | |
890 | return; | |
891 | ||
d7621d3c ZD |
892 | if (TREE_TYPE (*x) == TREE_TYPE (addr_var)) |
893 | { | |
894 | *x = addr_var; | |
895 | mark_new_vars_to_rename (stmt, vars_to_rename); | |
896 | return; | |
897 | } | |
898 | ||
68b9f53b | 899 | |
d7621d3c ZD |
900 | /* Frontends sometimes produce expressions like *&a instead of a[0]. |
901 | Create a temporary variable to handle this case. */ | |
902 | ass_stmt = build2 (MODIFY_EXPR, void_type_node, NULL_TREE, repl); | |
903 | new_var = duplicate_ssa_name (var, ass_stmt); | |
904 | TREE_OPERAND (*x, 0) = new_var; | |
905 | TREE_OPERAND (ass_stmt, 0) = new_var; | |
906 | ||
907 | bb = bb_for_stmt (stmt); | |
908 | tree_block_label (bb); | |
909 | bsi = bsi_after_labels (bb); | |
910 | bsi_insert_after (&bsi, ass_stmt, BSI_NEW_STMT); | |
911 | ||
912 | mark_new_vars_to_rename (stmt, vars_to_rename); | |
913 | } | |
6de9cd9a DN |
914 | |
915 | /* Replaces immediate uses of VAR by REPL. */ | |
916 | ||
917 | static void | |
918 | replace_immediate_uses (tree var, tree repl) | |
919 | { | |
6de9cd9a DN |
920 | int i, j, n; |
921 | dataflow_t df; | |
922 | tree stmt; | |
923 | stmt_ann_t ann; | |
d7621d3c | 924 | bool mark_new_vars; |
4c124b4c AM |
925 | ssa_op_iter iter; |
926 | use_operand_p use_p; | |
6de9cd9a DN |
927 | |
928 | df = get_immediate_uses (SSA_NAME_DEF_STMT (var)); | |
929 | n = num_immediate_uses (df); | |
930 | ||
931 | for (i = 0; i < n; i++) | |
932 | { | |
933 | stmt = immediate_use (df, i); | |
934 | ann = stmt_ann (stmt); | |
935 | ||
936 | if (TREE_CODE (stmt) == PHI_NODE) | |
937 | { | |
938 | for (j = 0; j < PHI_NUM_ARGS (stmt); j++) | |
939 | if (PHI_ARG_DEF (stmt, j) == var) | |
940 | { | |
d00ad49b | 941 | SET_PHI_ARG_DEF (stmt, j, repl); |
6de9cd9a DN |
942 | if (TREE_CODE (repl) == SSA_NAME |
943 | && PHI_ARG_EDGE (stmt, j)->flags & EDGE_ABNORMAL) | |
944 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (repl) = 1; | |
945 | } | |
946 | ||
947 | continue; | |
948 | } | |
949 | ||
950 | get_stmt_operands (stmt); | |
d7621d3c | 951 | mark_new_vars = false; |
6de9cd9a DN |
952 | if (is_gimple_reg (SSA_NAME_VAR (var))) |
953 | { | |
d7621d3c ZD |
954 | if (TREE_CODE (stmt) == MODIFY_EXPR) |
955 | { | |
956 | propagate_into_addr (stmt, var, &TREE_OPERAND (stmt, 0), repl); | |
957 | propagate_into_addr (stmt, var, &TREE_OPERAND (stmt, 1), repl); | |
958 | } | |
959 | ||
4c124b4c AM |
960 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) |
961 | if (USE_FROM_PTR (use_p) == var) | |
d7621d3c | 962 | { |
4c124b4c | 963 | propagate_value (use_p, repl); |
d7621d3c ZD |
964 | mark_new_vars = POINTER_TYPE_P (TREE_TYPE (repl)); |
965 | } | |
6de9cd9a DN |
966 | } |
967 | else | |
968 | { | |
4c124b4c AM |
969 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_VIRTUAL_USES) |
970 | if (USE_FROM_PTR (use_p) == var) | |
971 | propagate_value (use_p, repl); | |
6de9cd9a DN |
972 | } |
973 | ||
6de9cd9a DN |
974 | /* If REPL is a pointer, it may have different memory tags associated |
975 | with it. For instance, VAR may have had a name tag while REPL | |
976 | only had a type tag. In these cases, the virtual operands (if | |
977 | any) in the statement will refer to different symbols which need | |
978 | to be renamed. */ | |
d7621d3c | 979 | if (mark_new_vars) |
6de9cd9a | 980 | mark_new_vars_to_rename (stmt, vars_to_rename); |
d7621d3c ZD |
981 | else |
982 | modify_stmt (stmt); | |
6de9cd9a DN |
983 | } |
984 | } | |
985 | ||
048d9936 ZD |
986 | /* Gets the value VAR is equivalent to according to EQ_TO. */ |
987 | ||
988 | static tree | |
989 | get_eq_name (tree *eq_to, tree var) | |
990 | { | |
991 | unsigned ver; | |
992 | tree val = var; | |
993 | ||
994 | while (TREE_CODE (val) == SSA_NAME) | |
995 | { | |
996 | ver = SSA_NAME_VERSION (val); | |
997 | if (!eq_to[ver]) | |
998 | break; | |
999 | ||
1000 | val = eq_to[ver]; | |
1001 | } | |
1002 | ||
1003 | while (TREE_CODE (var) == SSA_NAME) | |
1004 | { | |
1005 | ver = SSA_NAME_VERSION (var); | |
1006 | if (!eq_to[ver]) | |
1007 | break; | |
1008 | ||
1009 | var = eq_to[ver]; | |
1010 | eq_to[ver] = val; | |
1011 | } | |
1012 | ||
1013 | return val; | |
1014 | } | |
1015 | ||
1016 | /* Checks whether phi node PHI is redundant and if it is, records the ssa name | |
1017 | its result is redundant to to EQ_TO array. */ | |
6de9cd9a DN |
1018 | |
1019 | static void | |
048d9936 | 1020 | check_phi_redundancy (tree phi, tree *eq_to) |
6de9cd9a | 1021 | { |
048d9936 ZD |
1022 | tree val = NULL_TREE, def, res = PHI_RESULT (phi), stmt; |
1023 | unsigned i, ver = SSA_NAME_VERSION (res), n; | |
6de9cd9a DN |
1024 | dataflow_t df; |
1025 | ||
048d9936 ZD |
1026 | /* It is unlikely that such large phi node would be redundant. */ |
1027 | if (PHI_NUM_ARGS (phi) > 16) | |
6de9cd9a DN |
1028 | return; |
1029 | ||
048d9936 | 1030 | for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++) |
6de9cd9a | 1031 | { |
048d9936 ZD |
1032 | def = PHI_ARG_DEF (phi, i); |
1033 | ||
1034 | if (TREE_CODE (def) == SSA_NAME) | |
1035 | { | |
1036 | def = get_eq_name (eq_to, def); | |
1037 | if (def == res) | |
1038 | continue; | |
1039 | } | |
1040 | ||
1041 | if (val | |
1042 | && !operand_equal_p (val, def, 0)) | |
6de9cd9a DN |
1043 | return; |
1044 | ||
048d9936 | 1045 | val = def; |
6de9cd9a | 1046 | } |
6de9cd9a | 1047 | |
048d9936 ZD |
1048 | /* At least one of the arguments should not be equal to the result, or |
1049 | something strange is happening. */ | |
1050 | if (!val) | |
1051 | abort (); | |
1052 | ||
1053 | if (get_eq_name (eq_to, res) == val) | |
1054 | return; | |
1055 | ||
1056 | if (!may_propagate_copy (res, val)) | |
1057 | return; | |
1058 | ||
1059 | eq_to[ver] = val; | |
1060 | ||
1061 | df = get_immediate_uses (SSA_NAME_DEF_STMT (res)); | |
6de9cd9a DN |
1062 | n = num_immediate_uses (df); |
1063 | ||
1064 | for (i = 0; i < n; i++) | |
1065 | { | |
1066 | stmt = immediate_use (df, i); | |
1067 | ||
048d9936 ZD |
1068 | if (TREE_CODE (stmt) == PHI_NODE) |
1069 | check_phi_redundancy (stmt, eq_to); | |
6de9cd9a DN |
1070 | } |
1071 | } | |
1072 | ||
1073 | /* Removes redundant phi nodes. | |
1074 | ||
1075 | A redundant PHI node is a PHI node where all of its PHI arguments | |
1076 | are the same value, excluding any PHI arguments which are the same | |
1077 | as the PHI result. | |
1078 | ||
1079 | A redundant PHI node is effectively a copy, so we forward copy propagate | |
1080 | which removes all uses of the destination of the PHI node then | |
1081 | finally we delete the redundant PHI node. | |
1082 | ||
1083 | Note that if we can not copy propagate the PHI node, then the PHI | |
1084 | will not be removed. Thus we do not have to worry about dependencies | |
1085 | between PHIs and the problems serializing PHIs into copies creates. | |
1086 | ||
1087 | The most important effect of this pass is to remove degenerate PHI | |
1088 | nodes created by removing unreachable code. */ | |
1089 | ||
c66b6c66 | 1090 | void |
6de9cd9a DN |
1091 | kill_redundant_phi_nodes (void) |
1092 | { | |
95a3742c | 1093 | tree *eq_to; |
048d9936 | 1094 | unsigned i, old_num_ssa_names; |
6de9cd9a | 1095 | basic_block bb; |
048d9936 ZD |
1096 | tree phi, var, repl, stmt; |
1097 | ||
1098 | /* The EQ_TO[VER] holds the value by that the ssa name VER should be | |
1099 | replaced. If EQ_TO[VER] is ssa name and it is decided to replace it by | |
1100 | other value, it may be necessary to follow the chain till the final value. | |
1101 | We perform path shortening (replacing the entries of the EQ_TO array with | |
1102 | heads of these chains) whenever we access the field to prevent quadratic | |
1103 | complexity (probably would not occur in practice anyway, but let us play | |
1104 | it safe). */ | |
95a3742c | 1105 | eq_to = xcalloc (num_ssa_names, sizeof (tree)); |
6de9cd9a DN |
1106 | |
1107 | /* We have had cases where computing immediate uses takes a | |
1108 | significant amount of compile time. If we run into such | |
1109 | problems here, we may want to only compute immediate uses for | |
1110 | a subset of all the SSA_NAMEs instead of computing it for | |
1111 | all of the SSA_NAMEs. */ | |
1112 | compute_immediate_uses (TDFA_USE_OPS | TDFA_USE_VOPS, NULL); | |
048d9936 | 1113 | old_num_ssa_names = num_ssa_names; |
6de9cd9a DN |
1114 | |
1115 | FOR_EACH_BB (bb) | |
1116 | { | |
048d9936 | 1117 | for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi)) |
6de9cd9a DN |
1118 | { |
1119 | var = PHI_RESULT (phi); | |
048d9936 | 1120 | check_phi_redundancy (phi, eq_to); |
6de9cd9a DN |
1121 | } |
1122 | } | |
1123 | ||
1124 | /* Now propagate the values. */ | |
048d9936 ZD |
1125 | for (i = 0; i < old_num_ssa_names; i++) |
1126 | { | |
1127 | if (!ssa_name (i)) | |
1128 | continue; | |
1129 | ||
1130 | repl = get_eq_name (eq_to, ssa_name (i)); | |
1131 | if (repl != ssa_name (i)) | |
1132 | replace_immediate_uses (ssa_name (i), repl); | |
1133 | } | |
6de9cd9a DN |
1134 | |
1135 | /* And remove the dead phis. */ | |
048d9936 ZD |
1136 | for (i = 0; i < old_num_ssa_names; i++) |
1137 | { | |
1138 | if (!ssa_name (i)) | |
1139 | continue; | |
1140 | ||
1141 | repl = get_eq_name (eq_to, ssa_name (i)); | |
1142 | if (repl != ssa_name (i)) | |
1143 | { | |
1144 | stmt = SSA_NAME_DEF_STMT (ssa_name (i)); | |
1145 | remove_phi_node (stmt, NULL_TREE, bb_for_stmt (stmt)); | |
1146 | } | |
1147 | } | |
6de9cd9a DN |
1148 | |
1149 | free_df (); | |
1150 | free (eq_to); | |
6de9cd9a DN |
1151 | } |
1152 | ||
1153 | struct tree_opt_pass pass_redundant_phi = | |
1154 | { | |
1155 | "redphi", /* name */ | |
1156 | NULL, /* gate */ | |
1157 | kill_redundant_phi_nodes, /* execute */ | |
1158 | NULL, /* sub */ | |
1159 | NULL, /* next */ | |
1160 | 0, /* static_pass_number */ | |
1161 | 0, /* tv_id */ | |
c1b763fa | 1162 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ |
6de9cd9a DN |
1163 | 0, /* properties_provided */ |
1164 | 0, /* properties_destroyed */ | |
1165 | 0, /* todo_flags_start */ | |
1166 | TODO_dump_func | TODO_rename_vars | |
1167 | | TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */ | |
1168 | }; | |
1169 | \f | |
1170 | /* Emit warnings for uninitialized variables. This is done in two passes. | |
1171 | ||
1172 | The first pass notices real uses of SSA names with default definitions. | |
1173 | Such uses are unconditionally uninitialized, and we can be certain that | |
1174 | such a use is a mistake. This pass is run before most optimizations, | |
1175 | so that we catch as many as we can. | |
1176 | ||
1177 | The second pass follows PHI nodes to find uses that are potentially | |
1178 | uninitialized. In this case we can't necessarily prove that the use | |
1179 | is really uninitialized. This pass is run after most optimizations, | |
1180 | so that we thread as many jumps and possible, and delete as much dead | |
1181 | code as possible, in order to reduce false positives. We also look | |
1182 | again for plain uninitialized variables, since optimization may have | |
1183 | changed conditionally uninitialized to unconditionally uninitialized. */ | |
1184 | ||
1185 | /* Emit a warning for T, an SSA_NAME, being uninitialized. The exact | |
1186 | warning text is in MSGID and LOCUS may contain a location or be null. */ | |
1187 | ||
1188 | static void | |
1189 | warn_uninit (tree t, const char *msgid, location_t *locus) | |
1190 | { | |
1191 | tree var = SSA_NAME_VAR (t); | |
1192 | tree def = SSA_NAME_DEF_STMT (t); | |
1193 | ||
1194 | /* Default uses (indicated by an empty definition statement), | |
1195 | are uninitialized. */ | |
1196 | if (!IS_EMPTY_STMT (def)) | |
1197 | return; | |
1198 | ||
1199 | /* Except for PARMs of course, which are always initialized. */ | |
1200 | if (TREE_CODE (var) == PARM_DECL) | |
1201 | return; | |
1202 | ||
1203 | /* Hard register variables get their initial value from the ether. */ | |
1204 | if (DECL_HARD_REGISTER (var)) | |
1205 | return; | |
1206 | ||
1207 | /* TREE_NO_WARNING either means we already warned, or the front end | |
1208 | wishes to suppress the warning. */ | |
1209 | if (TREE_NO_WARNING (var)) | |
1210 | return; | |
1211 | ||
1212 | if (!locus) | |
1213 | locus = &DECL_SOURCE_LOCATION (var); | |
1214 | warning (msgid, locus, var); | |
1215 | TREE_NO_WARNING (var) = 1; | |
1216 | } | |
1217 | ||
1218 | /* Called via walk_tree, look for SSA_NAMEs that have empty definitions | |
1219 | and warn about them. */ | |
1220 | ||
1221 | static tree | |
1222 | warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data) | |
1223 | { | |
1224 | location_t *locus = data; | |
1225 | tree t = *tp; | |
1226 | ||
1227 | /* We only do data flow with SSA_NAMEs, so that's all we can warn about. */ | |
1228 | if (TREE_CODE (t) == SSA_NAME) | |
1229 | { | |
1230 | warn_uninit (t, "%H'%D' is used uninitialized in this function", locus); | |
1231 | *walk_subtrees = 0; | |
1232 | } | |
1233 | else if (DECL_P (t) || TYPE_P (t)) | |
1234 | *walk_subtrees = 0; | |
1235 | ||
1236 | return NULL_TREE; | |
1237 | } | |
1238 | ||
1239 | /* Look for inputs to PHI that are SSA_NAMEs that have empty definitions | |
1240 | and warn about them. */ | |
1241 | ||
1242 | static void | |
1243 | warn_uninitialized_phi (tree phi) | |
1244 | { | |
1245 | int i, n = PHI_NUM_ARGS (phi); | |
1246 | ||
1247 | /* Don't look at memory tags. */ | |
1248 | if (!is_gimple_reg (PHI_RESULT (phi))) | |
1249 | return; | |
1250 | ||
1251 | for (i = 0; i < n; ++i) | |
1252 | { | |
1253 | tree op = PHI_ARG_DEF (phi, i); | |
1254 | if (TREE_CODE (op) == SSA_NAME) | |
1255 | warn_uninit (op, "%H'%D' may be used uninitialized in this function", | |
1256 | NULL); | |
1257 | } | |
1258 | } | |
1259 | ||
1260 | static void | |
1261 | execute_early_warn_uninitialized (void) | |
1262 | { | |
1263 | block_stmt_iterator bsi; | |
1264 | basic_block bb; | |
1265 | ||
1266 | FOR_EACH_BB (bb) | |
1267 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
1268 | walk_tree (bsi_stmt_ptr (bsi), warn_uninitialized_var, | |
1269 | EXPR_LOCUS (bsi_stmt (bsi)), NULL); | |
1270 | } | |
1271 | ||
1272 | static void | |
1273 | execute_late_warn_uninitialized (void) | |
1274 | { | |
1275 | basic_block bb; | |
1276 | tree phi; | |
1277 | ||
1278 | /* Re-do the plain uninitialized variable check, as optimization may have | |
1279 | straightened control flow. Do this first so that we don't accidentally | |
1280 | get a "may be" warning when we'd have seen an "is" warning later. */ | |
1281 | execute_early_warn_uninitialized (); | |
1282 | ||
1283 | FOR_EACH_BB (bb) | |
17192884 | 1284 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
6de9cd9a DN |
1285 | warn_uninitialized_phi (phi); |
1286 | } | |
1287 | ||
1288 | static bool | |
1289 | gate_warn_uninitialized (void) | |
1290 | { | |
1291 | return warn_uninitialized != 0; | |
1292 | } | |
1293 | ||
1294 | struct tree_opt_pass pass_early_warn_uninitialized = | |
1295 | { | |
1296 | NULL, /* name */ | |
1297 | gate_warn_uninitialized, /* gate */ | |
1298 | execute_early_warn_uninitialized, /* execute */ | |
1299 | NULL, /* sub */ | |
1300 | NULL, /* next */ | |
1301 | 0, /* static_pass_number */ | |
1302 | 0, /* tv_id */ | |
1303 | PROP_ssa, /* properties_required */ | |
1304 | 0, /* properties_provided */ | |
1305 | 0, /* properties_destroyed */ | |
1306 | 0, /* todo_flags_start */ | |
1307 | 0 /* todo_flags_finish */ | |
1308 | }; | |
1309 | ||
1310 | struct tree_opt_pass pass_late_warn_uninitialized = | |
1311 | { | |
1312 | NULL, /* name */ | |
1313 | gate_warn_uninitialized, /* gate */ | |
1314 | execute_late_warn_uninitialized, /* execute */ | |
1315 | NULL, /* sub */ | |
1316 | NULL, /* next */ | |
1317 | 0, /* static_pass_number */ | |
1318 | 0, /* tv_id */ | |
1319 | PROP_ssa, /* properties_required */ | |
1320 | 0, /* properties_provided */ | |
1321 | 0, /* properties_destroyed */ | |
1322 | 0, /* todo_flags_start */ | |
1323 | 0 /* todo_flags_finish */ | |
1324 | }; |