]>
Commit | Line | Data |
---|---|---|
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)); |
6de9cd9a DN |
507 | |
508 | timevar_push (TV_TREE_SSA_VERIFY); | |
509 | ||
53b4bf74 DN |
510 | /* Keep track of SSA names present in the IL. */ |
511 | for (i = 1; i < num_ssa_names; i++) | |
512 | TREE_VISITED (ssa_name (i)) = 0; | |
513 | ||
6de9cd9a DN |
514 | calculate_dominance_info (CDI_DOMINATORS); |
515 | ||
516 | /* Verify and register all the SSA_NAME definitions found in the | |
517 | function. */ | |
518 | FOR_EACH_BB (bb) | |
519 | { | |
520 | tree phi; | |
521 | block_stmt_iterator bsi; | |
522 | ||
17192884 | 523 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
53b4bf74 DN |
524 | if (verify_def (bb, definition_block, PHI_RESULT (phi), phi, |
525 | !is_gimple_reg (PHI_RESULT (phi)))) | |
526 | goto err; | |
6de9cd9a DN |
527 | |
528 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
529 | { | |
530 | tree stmt; | |
531 | stmt_ann_t ann; | |
532 | unsigned int j; | |
a32b97a2 BB |
533 | v_may_def_optype v_may_defs; |
534 | v_must_def_optype v_must_defs; | |
6de9cd9a DN |
535 | def_optype defs; |
536 | ||
537 | stmt = bsi_stmt (bsi); | |
538 | ann = stmt_ann (stmt); | |
539 | get_stmt_operands (stmt); | |
540 | ||
a32b97a2 BB |
541 | v_may_defs = V_MAY_DEF_OPS (ann); |
542 | if (ann->makes_aliased_stores && NUM_V_MAY_DEFS (v_may_defs) == 0) | |
53b4bf74 DN |
543 | { |
544 | error ("Statement makes aliased stores, but has no V_MAY_DEFS"); | |
545 | debug_generic_stmt (stmt); | |
546 | goto err; | |
547 | } | |
a32b97a2 BB |
548 | |
549 | for (j = 0; j < NUM_V_MAY_DEFS (v_may_defs); j++) | |
6de9cd9a | 550 | { |
a32b97a2 | 551 | tree op = V_MAY_DEF_RESULT (v_may_defs, j); |
53b4bf74 DN |
552 | if (verify_def (bb, definition_block, op, stmt, true)) |
553 | goto err; | |
6de9cd9a | 554 | } |
a32b97a2 BB |
555 | |
556 | v_must_defs = STMT_V_MUST_DEF_OPS (stmt); | |
557 | for (j = 0; j < NUM_V_MUST_DEFS (v_must_defs); j++) | |
558 | { | |
559 | tree op = V_MUST_DEF_OP (v_must_defs, j); | |
53b4bf74 DN |
560 | if (verify_def (bb, definition_block, op, stmt, true)) |
561 | goto err; | |
a32b97a2 | 562 | } |
6de9cd9a DN |
563 | |
564 | defs = DEF_OPS (ann); | |
565 | for (j = 0; j < NUM_DEFS (defs); j++) | |
566 | { | |
567 | tree op = DEF_OP (defs, j); | |
53b4bf74 DN |
568 | if (verify_def (bb, definition_block, op, stmt, false)) |
569 | goto err; | |
6de9cd9a DN |
570 | } |
571 | } | |
572 | } | |
573 | ||
574 | ||
575 | /* Now verify all the uses and make sure they agree with the definitions | |
576 | found in the previous pass. */ | |
577 | FOR_EACH_BB (bb) | |
578 | { | |
579 | edge e; | |
580 | tree phi; | |
581 | block_stmt_iterator bsi; | |
582 | ||
583 | /* Make sure that all edges have a clear 'aux' field. */ | |
584 | for (e = bb->pred; e; e = e->pred_next) | |
585 | { | |
586 | if (e->aux) | |
587 | { | |
588 | error ("AUX pointer initialized for edge %d->%d\n", e->src->index, | |
589 | e->dest->index); | |
53b4bf74 | 590 | goto err; |
6de9cd9a DN |
591 | } |
592 | } | |
593 | ||
594 | /* Verify the arguments for every PHI node in the block. */ | |
17192884 | 595 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
53b4bf74 DN |
596 | if (verify_phi_args (phi, bb, definition_block)) |
597 | goto err; | |
6de9cd9a | 598 | |
53b4bf74 | 599 | /* Now verify all the uses and vuses in every statement of the block. */ |
6de9cd9a DN |
600 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) |
601 | { | |
602 | tree stmt = bsi_stmt (bsi); | |
603 | stmt_ann_t ann = stmt_ann (stmt); | |
604 | unsigned int j; | |
605 | vuse_optype vuses; | |
a32b97a2 | 606 | v_may_def_optype v_may_defs; |
6de9cd9a DN |
607 | use_optype uses; |
608 | ||
fce66145 | 609 | vuses = VUSE_OPS (ann); |
6de9cd9a DN |
610 | for (j = 0; j < NUM_VUSES (vuses); j++) |
611 | { | |
612 | tree op = VUSE_OP (vuses, j); | |
53b4bf74 DN |
613 | if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)], |
614 | op, stmt, false, true)) | |
615 | goto err; | |
6de9cd9a DN |
616 | } |
617 | ||
a32b97a2 BB |
618 | v_may_defs = V_MAY_DEF_OPS (ann); |
619 | for (j = 0; j < NUM_V_MAY_DEFS (v_may_defs); j++) | |
6de9cd9a | 620 | { |
a32b97a2 | 621 | tree op = V_MAY_DEF_OP (v_may_defs, j); |
53b4bf74 DN |
622 | if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)], |
623 | op, stmt, false, true)) | |
624 | goto err; | |
6de9cd9a DN |
625 | } |
626 | ||
627 | uses = USE_OPS (ann); | |
628 | for (j = 0; j < NUM_USES (uses); j++) | |
629 | { | |
630 | tree op = USE_OP (uses, j); | |
53b4bf74 DN |
631 | if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)], |
632 | op, stmt, false, false)) | |
633 | goto err; | |
6de9cd9a DN |
634 | } |
635 | } | |
636 | } | |
637 | ||
53b4bf74 DN |
638 | /* Finally, verify alias information. */ |
639 | verify_alias_info (); | |
6de9cd9a | 640 | |
53b4bf74 | 641 | free (definition_block); |
6de9cd9a | 642 | timevar_pop (TV_TREE_SSA_VERIFY); |
53b4bf74 | 643 | return; |
6de9cd9a | 644 | |
53b4bf74 DN |
645 | err: |
646 | internal_error ("verify_ssa failed."); | |
6de9cd9a DN |
647 | } |
648 | ||
649 | ||
6de9cd9a DN |
650 | /* Initialize global DFA and SSA structures. */ |
651 | ||
652 | void | |
653 | init_tree_ssa (void) | |
654 | { | |
655 | VARRAY_TREE_INIT (referenced_vars, 20, "referenced_vars"); | |
656 | call_clobbered_vars = BITMAP_XMALLOC (); | |
a6d02559 | 657 | addressable_vars = BITMAP_XMALLOC (); |
6de9cd9a DN |
658 | init_ssa_operands (); |
659 | init_ssanames (); | |
660 | init_phinodes (); | |
661 | global_var = NULL_TREE; | |
6de9cd9a DN |
662 | } |
663 | ||
664 | ||
665 | /* Deallocate memory associated with SSA data structures for FNDECL. */ | |
666 | ||
667 | void | |
668 | delete_tree_ssa (void) | |
669 | { | |
670 | size_t i; | |
671 | basic_block bb; | |
672 | block_stmt_iterator bsi; | |
673 | ||
674 | /* Remove annotations from every tree in the function. */ | |
675 | FOR_EACH_BB (bb) | |
676 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
677 | bsi_stmt (bsi)->common.ann = NULL; | |
678 | ||
679 | /* Remove annotations from every referenced variable. */ | |
680 | if (referenced_vars) | |
681 | { | |
682 | for (i = 0; i < num_referenced_vars; i++) | |
683 | referenced_var (i)->common.ann = NULL; | |
684 | referenced_vars = NULL; | |
685 | } | |
686 | ||
687 | fini_ssanames (); | |
688 | fini_phinodes (); | |
689 | fini_ssa_operands (); | |
690 | ||
691 | global_var = NULL_TREE; | |
6b9bee8e | 692 | BITMAP_XFREE (call_clobbered_vars); |
6de9cd9a | 693 | call_clobbered_vars = NULL; |
a6d02559 DN |
694 | BITMAP_XFREE (addressable_vars); |
695 | addressable_vars = NULL; | |
6de9cd9a DN |
696 | } |
697 | ||
698 | ||
699 | /* Return true if EXPR is a useless type conversion, otherwise return | |
700 | false. */ | |
701 | ||
702 | bool | |
703 | tree_ssa_useless_type_conversion_1 (tree outer_type, tree inner_type) | |
704 | { | |
705 | /* If the inner and outer types are effectively the same, then | |
706 | strip the type conversion and enter the equivalence into | |
707 | the table. */ | |
708 | if (inner_type == outer_type | |
709 | || (lang_hooks.types_compatible_p (inner_type, outer_type))) | |
710 | return true; | |
711 | ||
712 | /* If both types are pointers and the outer type is a (void *), then | |
713 | the conversion is not necessary. The opposite is not true since | |
714 | that conversion would result in a loss of information if the | |
715 | equivalence was used. Consider an indirect function call where | |
716 | we need to know the exact type of the function to correctly | |
717 | implement the ABI. */ | |
718 | else if (POINTER_TYPE_P (inner_type) | |
719 | && POINTER_TYPE_P (outer_type) | |
720 | && TREE_CODE (TREE_TYPE (outer_type)) == VOID_TYPE) | |
721 | return true; | |
722 | ||
723 | /* Pointers and references are equivalent once we get to GENERIC, | |
724 | so strip conversions that just switch between them. */ | |
725 | else if (POINTER_TYPE_P (inner_type) | |
726 | && POINTER_TYPE_P (outer_type) | |
3facc4b6 AP |
727 | && lang_hooks.types_compatible_p (TREE_TYPE (inner_type), |
728 | TREE_TYPE (outer_type))) | |
6de9cd9a DN |
729 | return true; |
730 | ||
731 | /* If both the inner and outer types are integral types, then the | |
732 | conversion is not necessary if they have the same mode and | |
bc15d0ef JM |
733 | signedness and precision, and both or neither are boolean. Some |
734 | code assumes an invariant that boolean types stay boolean and do | |
735 | not become 1-bit bit-field types. Note that types with precision | |
736 | not using all bits of the mode (such as bit-field types in C) | |
737 | mean that testing of precision is necessary. */ | |
6de9cd9a DN |
738 | else if (INTEGRAL_TYPE_P (inner_type) |
739 | && INTEGRAL_TYPE_P (outer_type) | |
740 | && TYPE_MODE (inner_type) == TYPE_MODE (outer_type) | |
741 | && TYPE_UNSIGNED (inner_type) == TYPE_UNSIGNED (outer_type) | |
742 | && TYPE_PRECISION (inner_type) == TYPE_PRECISION (outer_type)) | |
bc15d0ef JM |
743 | { |
744 | bool first_boolean = (TREE_CODE (inner_type) == BOOLEAN_TYPE); | |
745 | bool second_boolean = (TREE_CODE (outer_type) == BOOLEAN_TYPE); | |
746 | if (first_boolean == second_boolean) | |
747 | return true; | |
748 | } | |
6de9cd9a DN |
749 | |
750 | /* Recurse for complex types. */ | |
751 | else if (TREE_CODE (inner_type) == COMPLEX_TYPE | |
752 | && TREE_CODE (outer_type) == COMPLEX_TYPE | |
753 | && tree_ssa_useless_type_conversion_1 (TREE_TYPE (outer_type), | |
754 | TREE_TYPE (inner_type))) | |
755 | return true; | |
756 | ||
757 | return false; | |
758 | } | |
759 | ||
760 | /* Return true if EXPR is a useless type conversion, otherwise return | |
761 | false. */ | |
762 | ||
763 | bool | |
764 | tree_ssa_useless_type_conversion (tree expr) | |
765 | { | |
766 | /* If we have an assignment that merely uses a NOP_EXPR to change | |
767 | the top of the RHS to the type of the LHS and the type conversion | |
768 | is "safe", then strip away the type conversion so that we can | |
769 | enter LHS = RHS into the const_and_copies table. */ | |
580d124f RK |
770 | if (TREE_CODE (expr) == NOP_EXPR || TREE_CODE (expr) == CONVERT_EXPR |
771 | || TREE_CODE (expr) == VIEW_CONVERT_EXPR | |
772 | || TREE_CODE (expr) == NON_LVALUE_EXPR) | |
6de9cd9a DN |
773 | return tree_ssa_useless_type_conversion_1 (TREE_TYPE (expr), |
774 | TREE_TYPE (TREE_OPERAND (expr, | |
775 | 0))); | |
776 | ||
777 | ||
778 | return false; | |
779 | } | |
780 | ||
781 | ||
782 | /* Internal helper for walk_use_def_chains. VAR, FN and DATA are as | |
53b4bf74 DN |
783 | described in walk_use_def_chains. |
784 | ||
785 | VISITED is a bitmap used to mark visited SSA_NAMEs to avoid | |
786 | infinite loops. | |
787 | ||
788 | IS_DFS is true if the caller wants to perform a depth-first search | |
789 | when visiting PHI nodes. A DFS will visit each PHI argument and | |
790 | call FN after each one. Otherwise, all the arguments are | |
791 | visited first and then FN is called with each of the visited | |
792 | arguments in a separate pass. */ | |
6de9cd9a DN |
793 | |
794 | static bool | |
795 | walk_use_def_chains_1 (tree var, walk_use_def_chains_fn fn, void *data, | |
53b4bf74 | 796 | bitmap visited, bool is_dfs) |
6de9cd9a DN |
797 | { |
798 | tree def_stmt; | |
799 | ||
800 | if (bitmap_bit_p (visited, SSA_NAME_VERSION (var))) | |
801 | return false; | |
802 | ||
803 | bitmap_set_bit (visited, SSA_NAME_VERSION (var)); | |
804 | ||
805 | def_stmt = SSA_NAME_DEF_STMT (var); | |
806 | ||
807 | if (TREE_CODE (def_stmt) != PHI_NODE) | |
808 | { | |
809 | /* If we reached the end of the use-def chain, call FN. */ | |
53b4bf74 | 810 | return fn (var, def_stmt, data); |
6de9cd9a DN |
811 | } |
812 | else | |
813 | { | |
814 | int i; | |
815 | ||
53b4bf74 DN |
816 | /* When doing a breadth-first search, call FN before following the |
817 | use-def links for each argument. */ | |
818 | if (!is_dfs) | |
819 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) | |
820 | if (fn (PHI_ARG_DEF (def_stmt, i), def_stmt, data)) | |
821 | return true; | |
822 | ||
823 | /* Follow use-def links out of each PHI argument. */ | |
6de9cd9a DN |
824 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) |
825 | { | |
826 | tree arg = PHI_ARG_DEF (def_stmt, i); | |
827 | if (TREE_CODE (arg) == SSA_NAME | |
53b4bf74 | 828 | && walk_use_def_chains_1 (arg, fn, data, visited, is_dfs)) |
6de9cd9a DN |
829 | return true; |
830 | } | |
53b4bf74 DN |
831 | |
832 | /* When doing a depth-first search, call FN after following the | |
833 | use-def links for each argument. */ | |
834 | if (is_dfs) | |
835 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) | |
836 | if (fn (PHI_ARG_DEF (def_stmt, i), def_stmt, data)) | |
837 | return true; | |
6de9cd9a | 838 | } |
53b4bf74 | 839 | |
6de9cd9a DN |
840 | return false; |
841 | } | |
842 | ||
843 | ||
844 | ||
53b4bf74 DN |
845 | /* Walk use-def chains starting at the SSA variable VAR. Call |
846 | function FN at each reaching definition found. FN takes three | |
847 | arguments: VAR, its defining statement (DEF_STMT) and a generic | |
848 | pointer to whatever state information that FN may want to maintain | |
849 | (DATA). FN is able to stop the walk by returning true, otherwise | |
850 | in order to continue the walk, FN should return false. | |
6de9cd9a DN |
851 | |
852 | Note, that if DEF_STMT is a PHI node, the semantics are slightly | |
53b4bf74 DN |
853 | different. The first argument to FN is no longer the original |
854 | variable VAR, but the PHI argument currently being examined. If FN | |
855 | wants to get at VAR, it should call PHI_RESULT (PHI). | |
856 | ||
857 | If IS_DFS is true, this function will: | |
6de9cd9a | 858 | |
53b4bf74 DN |
859 | 1- walk the use-def chains for all the PHI arguments, and, |
860 | 2- call (*FN) (ARG, PHI, DATA) on all the PHI arguments. | |
861 | ||
862 | If IS_DFS is false, the two steps above are done in reverse order | |
863 | (i.e., a breadth-first search). */ | |
6de9cd9a | 864 | |
6de9cd9a DN |
865 | |
866 | void | |
53b4bf74 DN |
867 | walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data, |
868 | bool is_dfs) | |
6de9cd9a DN |
869 | { |
870 | tree def_stmt; | |
871 | ||
872 | #if defined ENABLE_CHECKING | |
873 | if (TREE_CODE (var) != SSA_NAME) | |
874 | abort (); | |
875 | #endif | |
876 | ||
877 | def_stmt = SSA_NAME_DEF_STMT (var); | |
878 | ||
879 | /* We only need to recurse if the reaching definition comes from a PHI | |
880 | node. */ | |
881 | if (TREE_CODE (def_stmt) != PHI_NODE) | |
882 | (*fn) (var, def_stmt, data); | |
883 | else | |
884 | { | |
885 | bitmap visited = BITMAP_XMALLOC (); | |
53b4bf74 | 886 | walk_use_def_chains_1 (var, fn, data, visited, is_dfs); |
6de9cd9a DN |
887 | BITMAP_XFREE (visited); |
888 | } | |
889 | } | |
890 | ||
53b4bf74 | 891 | |
d7621d3c ZD |
892 | /* Replaces VAR with REPL in memory reference expression *X in |
893 | statement STMT. */ | |
894 | ||
895 | static void | |
896 | propagate_into_addr (tree stmt, tree var, tree *x, tree repl) | |
897 | { | |
898 | tree new_var, ass_stmt, addr_var; | |
899 | basic_block bb; | |
900 | block_stmt_iterator bsi; | |
901 | ||
902 | /* There is nothing special to handle in the other cases. */ | |
903 | if (TREE_CODE (repl) != ADDR_EXPR) | |
904 | return; | |
905 | addr_var = TREE_OPERAND (repl, 0); | |
906 | ||
907 | while (TREE_CODE (*x) == ARRAY_REF | |
908 | || TREE_CODE (*x) == COMPONENT_REF | |
909 | || TREE_CODE (*x) == BIT_FIELD_REF) | |
910 | x = &TREE_OPERAND (*x, 0); | |
911 | ||
912 | if (TREE_CODE (*x) != INDIRECT_REF | |
913 | || TREE_OPERAND (*x, 0) != var) | |
914 | return; | |
915 | ||
d7621d3c ZD |
916 | if (TREE_TYPE (*x) == TREE_TYPE (addr_var)) |
917 | { | |
918 | *x = addr_var; | |
919 | mark_new_vars_to_rename (stmt, vars_to_rename); | |
920 | return; | |
921 | } | |
922 | ||
68b9f53b | 923 | |
d7621d3c ZD |
924 | /* Frontends sometimes produce expressions like *&a instead of a[0]. |
925 | Create a temporary variable to handle this case. */ | |
926 | ass_stmt = build2 (MODIFY_EXPR, void_type_node, NULL_TREE, repl); | |
927 | new_var = duplicate_ssa_name (var, ass_stmt); | |
928 | TREE_OPERAND (*x, 0) = new_var; | |
929 | TREE_OPERAND (ass_stmt, 0) = new_var; | |
930 | ||
931 | bb = bb_for_stmt (stmt); | |
932 | tree_block_label (bb); | |
933 | bsi = bsi_after_labels (bb); | |
934 | bsi_insert_after (&bsi, ass_stmt, BSI_NEW_STMT); | |
935 | ||
936 | mark_new_vars_to_rename (stmt, vars_to_rename); | |
937 | } | |
6de9cd9a DN |
938 | |
939 | /* Replaces immediate uses of VAR by REPL. */ | |
940 | ||
941 | static void | |
942 | replace_immediate_uses (tree var, tree repl) | |
943 | { | |
944 | use_optype uses; | |
945 | vuse_optype vuses; | |
a32b97a2 | 946 | v_may_def_optype v_may_defs; |
6de9cd9a DN |
947 | int i, j, n; |
948 | dataflow_t df; | |
949 | tree stmt; | |
950 | stmt_ann_t ann; | |
d7621d3c | 951 | bool mark_new_vars; |
6de9cd9a DN |
952 | |
953 | df = get_immediate_uses (SSA_NAME_DEF_STMT (var)); | |
954 | n = num_immediate_uses (df); | |
955 | ||
956 | for (i = 0; i < n; i++) | |
957 | { | |
958 | stmt = immediate_use (df, i); | |
959 | ann = stmt_ann (stmt); | |
960 | ||
961 | if (TREE_CODE (stmt) == PHI_NODE) | |
962 | { | |
963 | for (j = 0; j < PHI_NUM_ARGS (stmt); j++) | |
964 | if (PHI_ARG_DEF (stmt, j) == var) | |
965 | { | |
d00ad49b | 966 | SET_PHI_ARG_DEF (stmt, j, repl); |
6de9cd9a DN |
967 | if (TREE_CODE (repl) == SSA_NAME |
968 | && PHI_ARG_EDGE (stmt, j)->flags & EDGE_ABNORMAL) | |
969 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (repl) = 1; | |
970 | } | |
971 | ||
972 | continue; | |
973 | } | |
974 | ||
975 | get_stmt_operands (stmt); | |
d7621d3c | 976 | mark_new_vars = false; |
6de9cd9a DN |
977 | if (is_gimple_reg (SSA_NAME_VAR (var))) |
978 | { | |
d7621d3c ZD |
979 | if (TREE_CODE (stmt) == MODIFY_EXPR) |
980 | { | |
981 | propagate_into_addr (stmt, var, &TREE_OPERAND (stmt, 0), repl); | |
982 | propagate_into_addr (stmt, var, &TREE_OPERAND (stmt, 1), repl); | |
983 | } | |
984 | ||
6de9cd9a DN |
985 | uses = USE_OPS (ann); |
986 | for (j = 0; j < (int) NUM_USES (uses); j++) | |
987 | if (USE_OP (uses, j) == var) | |
d7621d3c ZD |
988 | { |
989 | propagate_value (USE_OP_PTR (uses, j), repl); | |
990 | mark_new_vars = POINTER_TYPE_P (TREE_TYPE (repl)); | |
991 | } | |
6de9cd9a DN |
992 | } |
993 | else | |
994 | { | |
995 | vuses = VUSE_OPS (ann); | |
996 | for (j = 0; j < (int) NUM_VUSES (vuses); j++) | |
997 | if (VUSE_OP (vuses, j) == var) | |
998 | propagate_value (VUSE_OP_PTR (vuses, j), repl); | |
999 | ||
a32b97a2 BB |
1000 | v_may_defs = V_MAY_DEF_OPS (ann); |
1001 | for (j = 0; j < (int) NUM_V_MAY_DEFS (v_may_defs); j++) | |
1002 | if (V_MAY_DEF_OP (v_may_defs, j) == var) | |
1003 | propagate_value (V_MAY_DEF_OP_PTR (v_may_defs, j), repl); | |
6de9cd9a DN |
1004 | } |
1005 | ||
6de9cd9a DN |
1006 | /* If REPL is a pointer, it may have different memory tags associated |
1007 | with it. For instance, VAR may have had a name tag while REPL | |
1008 | only had a type tag. In these cases, the virtual operands (if | |
1009 | any) in the statement will refer to different symbols which need | |
1010 | to be renamed. */ | |
d7621d3c | 1011 | if (mark_new_vars) |
6de9cd9a | 1012 | mark_new_vars_to_rename (stmt, vars_to_rename); |
d7621d3c ZD |
1013 | else |
1014 | modify_stmt (stmt); | |
6de9cd9a DN |
1015 | } |
1016 | } | |
1017 | ||
048d9936 ZD |
1018 | /* Gets the value VAR is equivalent to according to EQ_TO. */ |
1019 | ||
1020 | static tree | |
1021 | get_eq_name (tree *eq_to, tree var) | |
1022 | { | |
1023 | unsigned ver; | |
1024 | tree val = var; | |
1025 | ||
1026 | while (TREE_CODE (val) == SSA_NAME) | |
1027 | { | |
1028 | ver = SSA_NAME_VERSION (val); | |
1029 | if (!eq_to[ver]) | |
1030 | break; | |
1031 | ||
1032 | val = eq_to[ver]; | |
1033 | } | |
1034 | ||
1035 | while (TREE_CODE (var) == SSA_NAME) | |
1036 | { | |
1037 | ver = SSA_NAME_VERSION (var); | |
1038 | if (!eq_to[ver]) | |
1039 | break; | |
1040 | ||
1041 | var = eq_to[ver]; | |
1042 | eq_to[ver] = val; | |
1043 | } | |
1044 | ||
1045 | return val; | |
1046 | } | |
1047 | ||
1048 | /* Checks whether phi node PHI is redundant and if it is, records the ssa name | |
1049 | its result is redundant to to EQ_TO array. */ | |
6de9cd9a DN |
1050 | |
1051 | static void | |
048d9936 | 1052 | check_phi_redundancy (tree phi, tree *eq_to) |
6de9cd9a | 1053 | { |
048d9936 ZD |
1054 | tree val = NULL_TREE, def, res = PHI_RESULT (phi), stmt; |
1055 | unsigned i, ver = SSA_NAME_VERSION (res), n; | |
6de9cd9a DN |
1056 | dataflow_t df; |
1057 | ||
048d9936 ZD |
1058 | /* It is unlikely that such large phi node would be redundant. */ |
1059 | if (PHI_NUM_ARGS (phi) > 16) | |
6de9cd9a DN |
1060 | return; |
1061 | ||
048d9936 | 1062 | for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++) |
6de9cd9a | 1063 | { |
048d9936 ZD |
1064 | def = PHI_ARG_DEF (phi, i); |
1065 | ||
1066 | if (TREE_CODE (def) == SSA_NAME) | |
1067 | { | |
1068 | def = get_eq_name (eq_to, def); | |
1069 | if (def == res) | |
1070 | continue; | |
1071 | } | |
1072 | ||
1073 | if (val | |
1074 | && !operand_equal_p (val, def, 0)) | |
6de9cd9a DN |
1075 | return; |
1076 | ||
048d9936 | 1077 | val = def; |
6de9cd9a | 1078 | } |
6de9cd9a | 1079 | |
048d9936 ZD |
1080 | /* At least one of the arguments should not be equal to the result, or |
1081 | something strange is happening. */ | |
1082 | if (!val) | |
1083 | abort (); | |
1084 | ||
1085 | if (get_eq_name (eq_to, res) == val) | |
1086 | return; | |
1087 | ||
1088 | if (!may_propagate_copy (res, val)) | |
1089 | return; | |
1090 | ||
1091 | eq_to[ver] = val; | |
1092 | ||
1093 | df = get_immediate_uses (SSA_NAME_DEF_STMT (res)); | |
6de9cd9a DN |
1094 | n = num_immediate_uses (df); |
1095 | ||
1096 | for (i = 0; i < n; i++) | |
1097 | { | |
1098 | stmt = immediate_use (df, i); | |
1099 | ||
048d9936 ZD |
1100 | if (TREE_CODE (stmt) == PHI_NODE) |
1101 | check_phi_redundancy (stmt, eq_to); | |
6de9cd9a DN |
1102 | } |
1103 | } | |
1104 | ||
1105 | /* Removes redundant phi nodes. | |
1106 | ||
1107 | A redundant PHI node is a PHI node where all of its PHI arguments | |
1108 | are the same value, excluding any PHI arguments which are the same | |
1109 | as the PHI result. | |
1110 | ||
1111 | A redundant PHI node is effectively a copy, so we forward copy propagate | |
1112 | which removes all uses of the destination of the PHI node then | |
1113 | finally we delete the redundant PHI node. | |
1114 | ||
1115 | Note that if we can not copy propagate the PHI node, then the PHI | |
1116 | will not be removed. Thus we do not have to worry about dependencies | |
1117 | between PHIs and the problems serializing PHIs into copies creates. | |
1118 | ||
1119 | The most important effect of this pass is to remove degenerate PHI | |
1120 | nodes created by removing unreachable code. */ | |
1121 | ||
c66b6c66 | 1122 | void |
6de9cd9a DN |
1123 | kill_redundant_phi_nodes (void) |
1124 | { | |
95a3742c | 1125 | tree *eq_to; |
048d9936 | 1126 | unsigned i, old_num_ssa_names; |
6de9cd9a | 1127 | basic_block bb; |
048d9936 ZD |
1128 | tree phi, var, repl, stmt; |
1129 | ||
1130 | /* The EQ_TO[VER] holds the value by that the ssa name VER should be | |
1131 | replaced. If EQ_TO[VER] is ssa name and it is decided to replace it by | |
1132 | other value, it may be necessary to follow the chain till the final value. | |
1133 | We perform path shortening (replacing the entries of the EQ_TO array with | |
1134 | heads of these chains) whenever we access the field to prevent quadratic | |
1135 | complexity (probably would not occur in practice anyway, but let us play | |
1136 | it safe). */ | |
95a3742c | 1137 | eq_to = xcalloc (num_ssa_names, sizeof (tree)); |
6de9cd9a DN |
1138 | |
1139 | /* We have had cases where computing immediate uses takes a | |
1140 | significant amount of compile time. If we run into such | |
1141 | problems here, we may want to only compute immediate uses for | |
1142 | a subset of all the SSA_NAMEs instead of computing it for | |
1143 | all of the SSA_NAMEs. */ | |
1144 | compute_immediate_uses (TDFA_USE_OPS | TDFA_USE_VOPS, NULL); | |
048d9936 | 1145 | old_num_ssa_names = num_ssa_names; |
6de9cd9a DN |
1146 | |
1147 | FOR_EACH_BB (bb) | |
1148 | { | |
048d9936 | 1149 | for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi)) |
6de9cd9a DN |
1150 | { |
1151 | var = PHI_RESULT (phi); | |
048d9936 | 1152 | check_phi_redundancy (phi, eq_to); |
6de9cd9a DN |
1153 | } |
1154 | } | |
1155 | ||
1156 | /* Now propagate the values. */ | |
048d9936 ZD |
1157 | for (i = 0; i < old_num_ssa_names; i++) |
1158 | { | |
1159 | if (!ssa_name (i)) | |
1160 | continue; | |
1161 | ||
1162 | repl = get_eq_name (eq_to, ssa_name (i)); | |
1163 | if (repl != ssa_name (i)) | |
1164 | replace_immediate_uses (ssa_name (i), repl); | |
1165 | } | |
6de9cd9a DN |
1166 | |
1167 | /* And remove the dead phis. */ | |
048d9936 ZD |
1168 | for (i = 0; i < old_num_ssa_names; i++) |
1169 | { | |
1170 | if (!ssa_name (i)) | |
1171 | continue; | |
1172 | ||
1173 | repl = get_eq_name (eq_to, ssa_name (i)); | |
1174 | if (repl != ssa_name (i)) | |
1175 | { | |
1176 | stmt = SSA_NAME_DEF_STMT (ssa_name (i)); | |
1177 | remove_phi_node (stmt, NULL_TREE, bb_for_stmt (stmt)); | |
1178 | } | |
1179 | } | |
6de9cd9a DN |
1180 | |
1181 | free_df (); | |
1182 | free (eq_to); | |
6de9cd9a DN |
1183 | } |
1184 | ||
1185 | struct tree_opt_pass pass_redundant_phi = | |
1186 | { | |
1187 | "redphi", /* name */ | |
1188 | NULL, /* gate */ | |
1189 | kill_redundant_phi_nodes, /* execute */ | |
1190 | NULL, /* sub */ | |
1191 | NULL, /* next */ | |
1192 | 0, /* static_pass_number */ | |
1193 | 0, /* tv_id */ | |
c1b763fa | 1194 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ |
6de9cd9a DN |
1195 | 0, /* properties_provided */ |
1196 | 0, /* properties_destroyed */ | |
1197 | 0, /* todo_flags_start */ | |
1198 | TODO_dump_func | TODO_rename_vars | |
1199 | | TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */ | |
1200 | }; | |
1201 | \f | |
1202 | /* Emit warnings for uninitialized variables. This is done in two passes. | |
1203 | ||
1204 | The first pass notices real uses of SSA names with default definitions. | |
1205 | Such uses are unconditionally uninitialized, and we can be certain that | |
1206 | such a use is a mistake. This pass is run before most optimizations, | |
1207 | so that we catch as many as we can. | |
1208 | ||
1209 | The second pass follows PHI nodes to find uses that are potentially | |
1210 | uninitialized. In this case we can't necessarily prove that the use | |
1211 | is really uninitialized. This pass is run after most optimizations, | |
1212 | so that we thread as many jumps and possible, and delete as much dead | |
1213 | code as possible, in order to reduce false positives. We also look | |
1214 | again for plain uninitialized variables, since optimization may have | |
1215 | changed conditionally uninitialized to unconditionally uninitialized. */ | |
1216 | ||
1217 | /* Emit a warning for T, an SSA_NAME, being uninitialized. The exact | |
1218 | warning text is in MSGID and LOCUS may contain a location or be null. */ | |
1219 | ||
1220 | static void | |
1221 | warn_uninit (tree t, const char *msgid, location_t *locus) | |
1222 | { | |
1223 | tree var = SSA_NAME_VAR (t); | |
1224 | tree def = SSA_NAME_DEF_STMT (t); | |
1225 | ||
1226 | /* Default uses (indicated by an empty definition statement), | |
1227 | are uninitialized. */ | |
1228 | if (!IS_EMPTY_STMT (def)) | |
1229 | return; | |
1230 | ||
1231 | /* Except for PARMs of course, which are always initialized. */ | |
1232 | if (TREE_CODE (var) == PARM_DECL) | |
1233 | return; | |
1234 | ||
1235 | /* Hard register variables get their initial value from the ether. */ | |
1236 | if (DECL_HARD_REGISTER (var)) | |
1237 | return; | |
1238 | ||
1239 | /* TREE_NO_WARNING either means we already warned, or the front end | |
1240 | wishes to suppress the warning. */ | |
1241 | if (TREE_NO_WARNING (var)) | |
1242 | return; | |
1243 | ||
1244 | if (!locus) | |
1245 | locus = &DECL_SOURCE_LOCATION (var); | |
1246 | warning (msgid, locus, var); | |
1247 | TREE_NO_WARNING (var) = 1; | |
1248 | } | |
1249 | ||
1250 | /* Called via walk_tree, look for SSA_NAMEs that have empty definitions | |
1251 | and warn about them. */ | |
1252 | ||
1253 | static tree | |
1254 | warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data) | |
1255 | { | |
1256 | location_t *locus = data; | |
1257 | tree t = *tp; | |
1258 | ||
1259 | /* We only do data flow with SSA_NAMEs, so that's all we can warn about. */ | |
1260 | if (TREE_CODE (t) == SSA_NAME) | |
1261 | { | |
1262 | warn_uninit (t, "%H'%D' is used uninitialized in this function", locus); | |
1263 | *walk_subtrees = 0; | |
1264 | } | |
1265 | else if (DECL_P (t) || TYPE_P (t)) | |
1266 | *walk_subtrees = 0; | |
1267 | ||
1268 | return NULL_TREE; | |
1269 | } | |
1270 | ||
1271 | /* Look for inputs to PHI that are SSA_NAMEs that have empty definitions | |
1272 | and warn about them. */ | |
1273 | ||
1274 | static void | |
1275 | warn_uninitialized_phi (tree phi) | |
1276 | { | |
1277 | int i, n = PHI_NUM_ARGS (phi); | |
1278 | ||
1279 | /* Don't look at memory tags. */ | |
1280 | if (!is_gimple_reg (PHI_RESULT (phi))) | |
1281 | return; | |
1282 | ||
1283 | for (i = 0; i < n; ++i) | |
1284 | { | |
1285 | tree op = PHI_ARG_DEF (phi, i); | |
1286 | if (TREE_CODE (op) == SSA_NAME) | |
1287 | warn_uninit (op, "%H'%D' may be used uninitialized in this function", | |
1288 | NULL); | |
1289 | } | |
1290 | } | |
1291 | ||
1292 | static void | |
1293 | execute_early_warn_uninitialized (void) | |
1294 | { | |
1295 | block_stmt_iterator bsi; | |
1296 | basic_block bb; | |
1297 | ||
1298 | FOR_EACH_BB (bb) | |
1299 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
1300 | walk_tree (bsi_stmt_ptr (bsi), warn_uninitialized_var, | |
1301 | EXPR_LOCUS (bsi_stmt (bsi)), NULL); | |
1302 | } | |
1303 | ||
1304 | static void | |
1305 | execute_late_warn_uninitialized (void) | |
1306 | { | |
1307 | basic_block bb; | |
1308 | tree phi; | |
1309 | ||
1310 | /* Re-do the plain uninitialized variable check, as optimization may have | |
1311 | straightened control flow. Do this first so that we don't accidentally | |
1312 | get a "may be" warning when we'd have seen an "is" warning later. */ | |
1313 | execute_early_warn_uninitialized (); | |
1314 | ||
1315 | FOR_EACH_BB (bb) | |
17192884 | 1316 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
6de9cd9a DN |
1317 | warn_uninitialized_phi (phi); |
1318 | } | |
1319 | ||
1320 | static bool | |
1321 | gate_warn_uninitialized (void) | |
1322 | { | |
1323 | return warn_uninitialized != 0; | |
1324 | } | |
1325 | ||
1326 | struct tree_opt_pass pass_early_warn_uninitialized = | |
1327 | { | |
1328 | NULL, /* name */ | |
1329 | gate_warn_uninitialized, /* gate */ | |
1330 | execute_early_warn_uninitialized, /* execute */ | |
1331 | NULL, /* sub */ | |
1332 | NULL, /* next */ | |
1333 | 0, /* static_pass_number */ | |
1334 | 0, /* tv_id */ | |
1335 | PROP_ssa, /* properties_required */ | |
1336 | 0, /* properties_provided */ | |
1337 | 0, /* properties_destroyed */ | |
1338 | 0, /* todo_flags_start */ | |
1339 | 0 /* todo_flags_finish */ | |
1340 | }; | |
1341 | ||
1342 | struct tree_opt_pass pass_late_warn_uninitialized = | |
1343 | { | |
1344 | NULL, /* name */ | |
1345 | gate_warn_uninitialized, /* gate */ | |
1346 | execute_late_warn_uninitialized, /* execute */ | |
1347 | NULL, /* sub */ | |
1348 | NULL, /* next */ | |
1349 | 0, /* static_pass_number */ | |
1350 | 0, /* tv_id */ | |
1351 | PROP_ssa, /* properties_required */ | |
1352 | 0, /* properties_provided */ | |
1353 | 0, /* properties_destroyed */ | |
1354 | 0, /* todo_flags_start */ | |
1355 | 0 /* todo_flags_finish */ | |
1356 | }; |