Mercurial > hg > CbC > CbC_gcc
comparison gcc/tree-eh.c @ 0:a06113de4d67
first commit
author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
---|---|
date | Fri, 17 Jul 2009 14:47:48 +0900 |
parents | |
children | 77e2b8dfacca |
comparison
equal
deleted
inserted
replaced
-1:000000000000 | 0:a06113de4d67 |
---|---|
1 /* Exception handling semantics and decomposition for trees. | |
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 | |
3 Free Software Foundation, Inc. | |
4 | |
5 This file is part of GCC. | |
6 | |
7 GCC is free software; you can redistribute it and/or modify | |
8 it under the terms of the GNU General Public License as published by | |
9 the Free Software Foundation; either version 3, or (at your option) | |
10 any later version. | |
11 | |
12 GCC is distributed in the hope that it will be useful, | |
13 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 GNU General Public License for more details. | |
16 | |
17 You should have received a copy of the GNU General Public License | |
18 along with GCC; see the file COPYING3. If not see | |
19 <http://www.gnu.org/licenses/>. */ | |
20 | |
21 #include "config.h" | |
22 #include "system.h" | |
23 #include "coretypes.h" | |
24 #include "tm.h" | |
25 #include "tree.h" | |
26 #include "rtl.h" | |
27 #include "tm_p.h" | |
28 #include "flags.h" | |
29 #include "function.h" | |
30 #include "except.h" | |
31 #include "tree-flow.h" | |
32 #include "tree-dump.h" | |
33 #include "tree-inline.h" | |
34 #include "tree-iterator.h" | |
35 #include "tree-pass.h" | |
36 #include "timevar.h" | |
37 #include "langhooks.h" | |
38 #include "ggc.h" | |
39 #include "toplev.h" | |
40 #include "gimple.h" | |
41 | |
42 /* In some instances a tree and a gimple need to be stored in a same table, | |
43 i.e. in hash tables. This is a structure to do this. */ | |
44 typedef union {tree *tp; tree t; gimple g;} treemple; | |
45 | |
46 /* Nonzero if we are using EH to handle cleanups. */ | |
47 static int using_eh_for_cleanups_p = 0; | |
48 | |
49 void | |
50 using_eh_for_cleanups (void) | |
51 { | |
52 using_eh_for_cleanups_p = 1; | |
53 } | |
54 | |
55 /* Misc functions used in this file. */ | |
56 | |
57 /* Compare and hash for any structure which begins with a canonical | |
58 pointer. Assumes all pointers are interchangeable, which is sort | |
59 of already assumed by gcc elsewhere IIRC. */ | |
60 | |
61 static int | |
62 struct_ptr_eq (const void *a, const void *b) | |
63 { | |
64 const void * const * x = (const void * const *) a; | |
65 const void * const * y = (const void * const *) b; | |
66 return *x == *y; | |
67 } | |
68 | |
69 static hashval_t | |
70 struct_ptr_hash (const void *a) | |
71 { | |
72 const void * const * x = (const void * const *) a; | |
73 return (size_t)*x >> 4; | |
74 } | |
75 | |
76 | |
77 /* Remember and lookup EH region data for arbitrary statements. | |
78 Really this means any statement that could_throw_p. We could | |
79 stuff this information into the stmt_ann data structure, but: | |
80 | |
81 (1) We absolutely rely on this information being kept until | |
82 we get to rtl. Once we're done with lowering here, if we lose | |
83 the information there's no way to recover it! | |
84 | |
85 (2) There are many more statements that *cannot* throw as | |
86 compared to those that can. We should be saving some amount | |
87 of space by only allocating memory for those that can throw. */ | |
88 | |
89 static void | |
90 record_stmt_eh_region (struct eh_region *region, gimple t) | |
91 { | |
92 if (!region) | |
93 return; | |
94 | |
95 add_stmt_to_eh_region (t, get_eh_region_number (region)); | |
96 } | |
97 | |
98 | |
99 /* Add statement T in function IFUN to EH region NUM. */ | |
100 | |
101 void | |
102 add_stmt_to_eh_region_fn (struct function *ifun, gimple t, int num) | |
103 { | |
104 struct throw_stmt_node *n; | |
105 void **slot; | |
106 | |
107 gcc_assert (num >= 0); | |
108 gcc_assert (gimple_code (t) != GIMPLE_RESX); | |
109 | |
110 n = GGC_NEW (struct throw_stmt_node); | |
111 n->stmt = t; | |
112 n->region_nr = num; | |
113 | |
114 if (!get_eh_throw_stmt_table (ifun)) | |
115 set_eh_throw_stmt_table (ifun, htab_create_ggc (31, struct_ptr_hash, | |
116 struct_ptr_eq, | |
117 ggc_free)); | |
118 | |
119 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), n, INSERT); | |
120 gcc_assert (!*slot); | |
121 *slot = n; | |
122 } | |
123 | |
124 | |
125 /* Add statement T in the current function (cfun) to EH region number | |
126 NUM. */ | |
127 | |
128 void | |
129 add_stmt_to_eh_region (gimple t, int num) | |
130 { | |
131 add_stmt_to_eh_region_fn (cfun, t, num); | |
132 } | |
133 | |
134 | |
135 /* Remove statement T in function IFUN from the EH region holding it. */ | |
136 | |
137 bool | |
138 remove_stmt_from_eh_region_fn (struct function *ifun, gimple t) | |
139 { | |
140 struct throw_stmt_node dummy; | |
141 void **slot; | |
142 | |
143 if (!get_eh_throw_stmt_table (ifun)) | |
144 return false; | |
145 | |
146 dummy.stmt = t; | |
147 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), &dummy, | |
148 NO_INSERT); | |
149 if (slot) | |
150 { | |
151 htab_clear_slot (get_eh_throw_stmt_table (ifun), slot); | |
152 return true; | |
153 } | |
154 else | |
155 return false; | |
156 } | |
157 | |
158 | |
159 /* Remove statement T in the current function (cfun) from the EH | |
160 region holding it. */ | |
161 | |
162 bool | |
163 remove_stmt_from_eh_region (gimple t) | |
164 { | |
165 return remove_stmt_from_eh_region_fn (cfun, t); | |
166 } | |
167 | |
168 /* Determine if statement T is inside an EH region in function IFUN. | |
169 Return the EH region number if found, return -2 if IFUN does not | |
170 have an EH table and -1 if T could not be found in IFUN's EH region | |
171 table. */ | |
172 | |
173 int | |
174 lookup_stmt_eh_region_fn (struct function *ifun, gimple t) | |
175 { | |
176 struct throw_stmt_node *p, n; | |
177 | |
178 if (!get_eh_throw_stmt_table (ifun)) | |
179 return -2; | |
180 | |
181 n.stmt = t; | |
182 p = (struct throw_stmt_node *) htab_find (get_eh_throw_stmt_table (ifun), &n); | |
183 return (p ? p->region_nr : -1); | |
184 } | |
185 | |
186 | |
187 /* Determine if statement T is inside an EH region in the current | |
188 function (cfun). Return the EH region number if found, return -2 | |
189 if cfun does not have an EH table and -1 if T could not be found in | |
190 cfun's EH region table. */ | |
191 | |
192 int | |
193 lookup_stmt_eh_region (gimple t) | |
194 { | |
195 /* We can get called from initialized data when -fnon-call-exceptions | |
196 is on; prevent crash. */ | |
197 if (!cfun) | |
198 return -1; | |
199 | |
200 return lookup_stmt_eh_region_fn (cfun, t); | |
201 } | |
202 | |
203 | |
204 /* Determine if expression T is inside an EH region in the current | |
205 function (cfun). Return the EH region number if found, return -2 | |
206 if IFUN does not have an EH table and -1 if T could not be found in | |
207 IFUN's EH region table. */ | |
208 | |
209 int | |
210 lookup_expr_eh_region (tree t) | |
211 { | |
212 /* We can get called from initialized data when -fnon-call-exceptions | |
213 is on; prevent crash. */ | |
214 if (!cfun) | |
215 return -1; | |
216 | |
217 if (!get_eh_throw_stmt_table (cfun)) | |
218 return -2; | |
219 | |
220 if (t && EXPR_P (t)) | |
221 { | |
222 tree_ann_common_t ann = tree_common_ann (t); | |
223 if (ann) | |
224 return (int) ann->rn; | |
225 } | |
226 | |
227 return -1; | |
228 } | |
229 | |
230 | |
231 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY | |
232 nodes and LABEL_DECL nodes. We will use this during the second phase to | |
233 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */ | |
234 | |
235 struct finally_tree_node | |
236 { | |
237 /* When storing a GIMPLE_TRY, we have to record a gimple. However | |
238 when deciding whether a GOTO to a certain LABEL_DECL (which is a | |
239 tree) leaves the TRY block, its necessary to record a tree in | |
240 this field. Thus a treemple is used. */ | |
241 treemple child; | |
242 gimple parent; | |
243 }; | |
244 | |
245 /* Note that this table is *not* marked GTY. It is short-lived. */ | |
246 static htab_t finally_tree; | |
247 | |
248 static void | |
249 record_in_finally_tree (treemple child, gimple parent) | |
250 { | |
251 struct finally_tree_node *n; | |
252 void **slot; | |
253 | |
254 n = XNEW (struct finally_tree_node); | |
255 n->child = child; | |
256 n->parent = parent; | |
257 | |
258 slot = htab_find_slot (finally_tree, n, INSERT); | |
259 gcc_assert (!*slot); | |
260 *slot = n; | |
261 } | |
262 | |
263 static void | |
264 collect_finally_tree (gimple stmt, gimple region); | |
265 | |
266 /* Go through the gimple sequence. Works with collect_finally_tree to | |
267 record all GIMPLE_LABEL and GIMPLE_TRY statements. */ | |
268 | |
269 static void | |
270 collect_finally_tree_1 (gimple_seq seq, gimple region) | |
271 { | |
272 gimple_stmt_iterator gsi; | |
273 | |
274 for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi)) | |
275 collect_finally_tree (gsi_stmt (gsi), region); | |
276 } | |
277 | |
278 static void | |
279 collect_finally_tree (gimple stmt, gimple region) | |
280 { | |
281 treemple temp; | |
282 | |
283 switch (gimple_code (stmt)) | |
284 { | |
285 case GIMPLE_LABEL: | |
286 temp.t = gimple_label_label (stmt); | |
287 record_in_finally_tree (temp, region); | |
288 break; | |
289 | |
290 case GIMPLE_TRY: | |
291 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY) | |
292 { | |
293 temp.g = stmt; | |
294 record_in_finally_tree (temp, region); | |
295 collect_finally_tree_1 (gimple_try_eval (stmt), stmt); | |
296 collect_finally_tree_1 (gimple_try_cleanup (stmt), region); | |
297 } | |
298 else if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH) | |
299 { | |
300 collect_finally_tree_1 (gimple_try_eval (stmt), region); | |
301 collect_finally_tree_1 (gimple_try_cleanup (stmt), region); | |
302 } | |
303 break; | |
304 | |
305 case GIMPLE_CATCH: | |
306 collect_finally_tree_1 (gimple_catch_handler (stmt), region); | |
307 break; | |
308 | |
309 case GIMPLE_EH_FILTER: | |
310 collect_finally_tree_1 (gimple_eh_filter_failure (stmt), region); | |
311 break; | |
312 | |
313 default: | |
314 /* A type, a decl, or some kind of statement that we're not | |
315 interested in. Don't walk them. */ | |
316 break; | |
317 } | |
318 } | |
319 | |
320 | |
321 /* Use the finally tree to determine if a jump from START to TARGET | |
322 would leave the try_finally node that START lives in. */ | |
323 | |
324 static bool | |
325 outside_finally_tree (treemple start, gimple target) | |
326 { | |
327 struct finally_tree_node n, *p; | |
328 | |
329 do | |
330 { | |
331 n.child = start; | |
332 p = (struct finally_tree_node *) htab_find (finally_tree, &n); | |
333 if (!p) | |
334 return true; | |
335 start.g = p->parent; | |
336 } | |
337 while (start.g != target); | |
338 | |
339 return false; | |
340 } | |
341 | |
342 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY | |
343 nodes into a set of gotos, magic labels, and eh regions. | |
344 The eh region creation is straight-forward, but frobbing all the gotos | |
345 and such into shape isn't. */ | |
346 | |
347 /* State of the world while lowering. */ | |
348 | |
349 struct leh_state | |
350 { | |
351 /* What's "current" while constructing the eh region tree. These | |
352 correspond to variables of the same name in cfun->eh, which we | |
353 don't have easy access to. */ | |
354 struct eh_region *cur_region; | |
355 struct eh_region *prev_try; | |
356 | |
357 /* Processing of TRY_FINALLY requires a bit more state. This is | |
358 split out into a separate structure so that we don't have to | |
359 copy so much when processing other nodes. */ | |
360 struct leh_tf_state *tf; | |
361 }; | |
362 | |
363 struct leh_tf_state | |
364 { | |
365 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The | |
366 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain | |
367 this so that outside_finally_tree can reliably reference the tree used | |
368 in the collect_finally_tree data structures. */ | |
369 gimple try_finally_expr; | |
370 gimple top_p; | |
371 /* While lowering a top_p usually it is expanded into multiple statements, | |
372 thus we need the following field to store them. */ | |
373 gimple_seq top_p_seq; | |
374 | |
375 /* The state outside this try_finally node. */ | |
376 struct leh_state *outer; | |
377 | |
378 /* The exception region created for it. */ | |
379 struct eh_region *region; | |
380 | |
381 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN statements | |
382 that are seen to escape this GIMPLE_TRY_FINALLY node. | |
383 The idea is to record a gimple statement for everything except for | |
384 the conditionals, which get their labels recorded. Since labels are of | |
385 type 'tree', we need this node to store both gimple and tree objects. | |
386 REPL_STMT is the sequence used to replace the goto/return statement. | |
387 CONT_STMT is used to store the statement that allows the return/goto to | |
388 jump to the original destination. */ | |
389 struct goto_queue_node { | |
390 treemple stmt; | |
391 gimple_seq repl_stmt; | |
392 gimple cont_stmt; | |
393 int index; | |
394 /* this is used when index >= 0 to indicate that stmt is a label(as | |
395 opposed to a goto stmt) */ | |
396 int is_label; | |
397 } *goto_queue; | |
398 size_t goto_queue_size; | |
399 size_t goto_queue_active; | |
400 | |
401 /* Pointer map to help in searching goto_queue when it is large. */ | |
402 struct pointer_map_t *goto_queue_map; | |
403 | |
404 /* The set of unique labels seen as entries in the goto queue. */ | |
405 VEC(tree,heap) *dest_array; | |
406 | |
407 /* A label to be added at the end of the completed transformed | |
408 sequence. It will be set if may_fallthru was true *at one time*, | |
409 though subsequent transformations may have cleared that flag. */ | |
410 tree fallthru_label; | |
411 | |
412 /* A label that has been registered with except.c to be the | |
413 landing pad for this try block. */ | |
414 tree eh_label; | |
415 | |
416 /* True if it is possible to fall out the bottom of the try block. | |
417 Cleared if the fallthru is converted to a goto. */ | |
418 bool may_fallthru; | |
419 | |
420 /* True if any entry in goto_queue is a GIMPLE_RETURN. */ | |
421 bool may_return; | |
422 | |
423 /* True if the finally block can receive an exception edge. | |
424 Cleared if the exception case is handled by code duplication. */ | |
425 bool may_throw; | |
426 }; | |
427 | |
428 static gimple_seq lower_eh_filter (struct leh_state *, gimple); | |
429 | |
430 /* Search for STMT in the goto queue. Return the replacement, | |
431 or null if the statement isn't in the queue. */ | |
432 | |
433 #define LARGE_GOTO_QUEUE 20 | |
434 | |
435 static void lower_eh_constructs_1 (struct leh_state *state, gimple_seq seq); | |
436 | |
437 static gimple_seq | |
438 find_goto_replacement (struct leh_tf_state *tf, treemple stmt) | |
439 { | |
440 unsigned int i; | |
441 void **slot; | |
442 | |
443 if (tf->goto_queue_active < LARGE_GOTO_QUEUE) | |
444 { | |
445 for (i = 0; i < tf->goto_queue_active; i++) | |
446 if ( tf->goto_queue[i].stmt.g == stmt.g) | |
447 return tf->goto_queue[i].repl_stmt; | |
448 return NULL; | |
449 } | |
450 | |
451 /* If we have a large number of entries in the goto_queue, create a | |
452 pointer map and use that for searching. */ | |
453 | |
454 if (!tf->goto_queue_map) | |
455 { | |
456 tf->goto_queue_map = pointer_map_create (); | |
457 for (i = 0; i < tf->goto_queue_active; i++) | |
458 { | |
459 slot = pointer_map_insert (tf->goto_queue_map, | |
460 tf->goto_queue[i].stmt.g); | |
461 gcc_assert (*slot == NULL); | |
462 *slot = &tf->goto_queue[i]; | |
463 } | |
464 } | |
465 | |
466 slot = pointer_map_contains (tf->goto_queue_map, stmt.g); | |
467 if (slot != NULL) | |
468 return (((struct goto_queue_node *) *slot)->repl_stmt); | |
469 | |
470 return NULL; | |
471 } | |
472 | |
473 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a | |
474 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto, | |
475 then we can just splat it in, otherwise we add the new stmts immediately | |
476 after the GIMPLE_COND and redirect. */ | |
477 | |
478 static void | |
479 replace_goto_queue_cond_clause (tree *tp, struct leh_tf_state *tf, | |
480 gimple_stmt_iterator *gsi) | |
481 { | |
482 tree label; | |
483 gimple_seq new_seq; | |
484 treemple temp; | |
485 | |
486 temp.tp = tp; | |
487 new_seq = find_goto_replacement (tf, temp); | |
488 if (!new_seq) | |
489 return; | |
490 | |
491 if (gimple_seq_singleton_p (new_seq) | |
492 && gimple_code (gimple_seq_first_stmt (new_seq)) == GIMPLE_GOTO) | |
493 { | |
494 *tp = gimple_goto_dest (gimple_seq_first_stmt (new_seq)); | |
495 return; | |
496 } | |
497 | |
498 label = create_artificial_label (); | |
499 /* Set the new label for the GIMPLE_COND */ | |
500 *tp = label; | |
501 | |
502 gsi_insert_after (gsi, gimple_build_label (label), GSI_CONTINUE_LINKING); | |
503 gsi_insert_seq_after (gsi, gimple_seq_copy (new_seq), GSI_CONTINUE_LINKING); | |
504 } | |
505 | |
506 /* The real work of replace_goto_queue. Returns with TSI updated to | |
507 point to the next statement. */ | |
508 | |
509 static void replace_goto_queue_stmt_list (gimple_seq, struct leh_tf_state *); | |
510 | |
511 static void | |
512 replace_goto_queue_1 (gimple stmt, struct leh_tf_state *tf, | |
513 gimple_stmt_iterator *gsi) | |
514 { | |
515 gimple_seq seq; | |
516 treemple temp; | |
517 temp.g = NULL; | |
518 | |
519 switch (gimple_code (stmt)) | |
520 { | |
521 case GIMPLE_GOTO: | |
522 case GIMPLE_RETURN: | |
523 temp.g = stmt; | |
524 seq = find_goto_replacement (tf, temp); | |
525 if (seq) | |
526 { | |
527 gsi_insert_seq_before (gsi, gimple_seq_copy (seq), GSI_SAME_STMT); | |
528 gsi_remove (gsi, false); | |
529 return; | |
530 } | |
531 break; | |
532 | |
533 case GIMPLE_COND: | |
534 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 2), tf, gsi); | |
535 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 3), tf, gsi); | |
536 break; | |
537 | |
538 case GIMPLE_TRY: | |
539 replace_goto_queue_stmt_list (gimple_try_eval (stmt), tf); | |
540 replace_goto_queue_stmt_list (gimple_try_cleanup (stmt), tf); | |
541 break; | |
542 case GIMPLE_CATCH: | |
543 replace_goto_queue_stmt_list (gimple_catch_handler (stmt), tf); | |
544 break; | |
545 case GIMPLE_EH_FILTER: | |
546 replace_goto_queue_stmt_list (gimple_eh_filter_failure (stmt), tf); | |
547 break; | |
548 | |
549 default: | |
550 /* These won't have gotos in them. */ | |
551 break; | |
552 } | |
553 | |
554 gsi_next (gsi); | |
555 } | |
556 | |
557 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */ | |
558 | |
559 static void | |
560 replace_goto_queue_stmt_list (gimple_seq seq, struct leh_tf_state *tf) | |
561 { | |
562 gimple_stmt_iterator gsi = gsi_start (seq); | |
563 | |
564 while (!gsi_end_p (gsi)) | |
565 replace_goto_queue_1 (gsi_stmt (gsi), tf, &gsi); | |
566 } | |
567 | |
568 /* Replace all goto queue members. */ | |
569 | |
570 static void | |
571 replace_goto_queue (struct leh_tf_state *tf) | |
572 { | |
573 if (tf->goto_queue_active == 0) | |
574 return; | |
575 replace_goto_queue_stmt_list (tf->top_p_seq, tf); | |
576 } | |
577 | |
578 /* Add a new record to the goto queue contained in TF. NEW_STMT is the | |
579 data to be added, IS_LABEL indicates whether NEW_STMT is a label or | |
580 a gimple return. */ | |
581 | |
582 static void | |
583 record_in_goto_queue (struct leh_tf_state *tf, | |
584 treemple new_stmt, | |
585 int index, | |
586 bool is_label) | |
587 { | |
588 size_t active, size; | |
589 struct goto_queue_node *q; | |
590 | |
591 gcc_assert (!tf->goto_queue_map); | |
592 | |
593 active = tf->goto_queue_active; | |
594 size = tf->goto_queue_size; | |
595 if (active >= size) | |
596 { | |
597 size = (size ? size * 2 : 32); | |
598 tf->goto_queue_size = size; | |
599 tf->goto_queue | |
600 = XRESIZEVEC (struct goto_queue_node, tf->goto_queue, size); | |
601 } | |
602 | |
603 q = &tf->goto_queue[active]; | |
604 tf->goto_queue_active = active + 1; | |
605 | |
606 memset (q, 0, sizeof (*q)); | |
607 q->stmt = new_stmt; | |
608 q->index = index; | |
609 q->is_label = is_label; | |
610 } | |
611 | |
612 /* Record the LABEL label in the goto queue contained in TF. | |
613 TF is not null. */ | |
614 | |
615 static void | |
616 record_in_goto_queue_label (struct leh_tf_state *tf, treemple stmt, tree label) | |
617 { | |
618 int index; | |
619 treemple temp, new_stmt; | |
620 | |
621 if (!label) | |
622 return; | |
623 | |
624 /* Computed and non-local gotos do not get processed. Given | |
625 their nature we can neither tell whether we've escaped the | |
626 finally block nor redirect them if we knew. */ | |
627 if (TREE_CODE (label) != LABEL_DECL) | |
628 return; | |
629 | |
630 /* No need to record gotos that don't leave the try block. */ | |
631 temp.t = label; | |
632 if (!outside_finally_tree (temp, tf->try_finally_expr)) | |
633 return; | |
634 | |
635 if (! tf->dest_array) | |
636 { | |
637 tf->dest_array = VEC_alloc (tree, heap, 10); | |
638 VEC_quick_push (tree, tf->dest_array, label); | |
639 index = 0; | |
640 } | |
641 else | |
642 { | |
643 int n = VEC_length (tree, tf->dest_array); | |
644 for (index = 0; index < n; ++index) | |
645 if (VEC_index (tree, tf->dest_array, index) == label) | |
646 break; | |
647 if (index == n) | |
648 VEC_safe_push (tree, heap, tf->dest_array, label); | |
649 } | |
650 | |
651 /* In the case of a GOTO we want to record the destination label, | |
652 since with a GIMPLE_COND we have an easy access to the then/else | |
653 labels. */ | |
654 new_stmt = stmt; | |
655 record_in_goto_queue (tf, new_stmt, index, true); | |
656 | |
657 } | |
658 | |
659 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally | |
660 node, and if so record that fact in the goto queue associated with that | |
661 try_finally node. */ | |
662 | |
663 static void | |
664 maybe_record_in_goto_queue (struct leh_state *state, gimple stmt) | |
665 { | |
666 struct leh_tf_state *tf = state->tf; | |
667 treemple new_stmt; | |
668 | |
669 if (!tf) | |
670 return; | |
671 | |
672 switch (gimple_code (stmt)) | |
673 { | |
674 case GIMPLE_COND: | |
675 new_stmt.tp = gimple_op_ptr (stmt, 2); | |
676 record_in_goto_queue_label (tf, new_stmt, gimple_cond_true_label (stmt)); | |
677 new_stmt.tp = gimple_op_ptr (stmt, 3); | |
678 record_in_goto_queue_label (tf, new_stmt, gimple_cond_false_label (stmt)); | |
679 break; | |
680 case GIMPLE_GOTO: | |
681 new_stmt.g = stmt; | |
682 record_in_goto_queue_label (tf, new_stmt, gimple_goto_dest (stmt)); | |
683 break; | |
684 | |
685 case GIMPLE_RETURN: | |
686 tf->may_return = true; | |
687 new_stmt.g = stmt; | |
688 record_in_goto_queue (tf, new_stmt, -1, false); | |
689 break; | |
690 | |
691 default: | |
692 gcc_unreachable (); | |
693 } | |
694 } | |
695 | |
696 | |
697 #ifdef ENABLE_CHECKING | |
698 /* We do not process GIMPLE_SWITCHes for now. As long as the original source | |
699 was in fact structured, and we've not yet done jump threading, then none | |
700 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */ | |
701 | |
702 static void | |
703 verify_norecord_switch_expr (struct leh_state *state, gimple switch_expr) | |
704 { | |
705 struct leh_tf_state *tf = state->tf; | |
706 size_t i, n; | |
707 | |
708 if (!tf) | |
709 return; | |
710 | |
711 n = gimple_switch_num_labels (switch_expr); | |
712 | |
713 for (i = 0; i < n; ++i) | |
714 { | |
715 treemple temp; | |
716 tree lab = CASE_LABEL (gimple_switch_label (switch_expr, i)); | |
717 temp.t = lab; | |
718 gcc_assert (!outside_finally_tree (temp, tf->try_finally_expr)); | |
719 } | |
720 } | |
721 #else | |
722 #define verify_norecord_switch_expr(state, switch_expr) | |
723 #endif | |
724 | |
725 /* Redirect a RETURN_EXPR pointed to by STMT_P to FINLAB. Place in CONT_P | |
726 whatever is needed to finish the return. If MOD is non-null, insert it | |
727 before the new branch. RETURN_VALUE_P is a cache containing a temporary | |
728 variable to be used in manipulating the value returned from the function. */ | |
729 | |
730 static void | |
731 do_return_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod, | |
732 tree *return_value_p) | |
733 { | |
734 tree ret_expr; | |
735 gimple x; | |
736 | |
737 /* In the case of a return, the queue node must be a gimple statement. */ | |
738 gcc_assert (!q->is_label); | |
739 | |
740 ret_expr = gimple_return_retval (q->stmt.g); | |
741 | |
742 if (ret_expr) | |
743 { | |
744 if (!*return_value_p) | |
745 *return_value_p = ret_expr; | |
746 else | |
747 gcc_assert (*return_value_p == ret_expr); | |
748 q->cont_stmt = q->stmt.g; | |
749 /* The nasty part about redirecting the return value is that the | |
750 return value itself is to be computed before the FINALLY block | |
751 is executed. e.g. | |
752 | |
753 int x; | |
754 int foo (void) | |
755 { | |
756 x = 0; | |
757 try { | |
758 return x; | |
759 } finally { | |
760 x++; | |
761 } | |
762 } | |
763 | |
764 should return 0, not 1. Arrange for this to happen by copying | |
765 computed the return value into a local temporary. This also | |
766 allows us to redirect multiple return statements through the | |
767 same destination block; whether this is a net win or not really | |
768 depends, I guess, but it does make generation of the switch in | |
769 lower_try_finally_switch easier. */ | |
770 | |
771 if (TREE_CODE (ret_expr) == RESULT_DECL) | |
772 { | |
773 if (!*return_value_p) | |
774 *return_value_p = ret_expr; | |
775 else | |
776 gcc_assert (*return_value_p == ret_expr); | |
777 q->cont_stmt = q->stmt.g; | |
778 } | |
779 else | |
780 gcc_unreachable (); | |
781 } | |
782 else | |
783 /* If we don't return a value, all return statements are the same. */ | |
784 q->cont_stmt = q->stmt.g; | |
785 | |
786 if (!q->repl_stmt) | |
787 q->repl_stmt = gimple_seq_alloc (); | |
788 | |
789 if (mod) | |
790 gimple_seq_add_seq (&q->repl_stmt, mod); | |
791 | |
792 x = gimple_build_goto (finlab); | |
793 gimple_seq_add_stmt (&q->repl_stmt, x); | |
794 } | |
795 | |
796 /* Similar, but easier, for GIMPLE_GOTO. */ | |
797 | |
798 static void | |
799 do_goto_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod, | |
800 struct leh_tf_state *tf) | |
801 { | |
802 gimple x; | |
803 | |
804 gcc_assert (q->is_label); | |
805 if (!q->repl_stmt) | |
806 q->repl_stmt = gimple_seq_alloc (); | |
807 | |
808 q->cont_stmt = gimple_build_goto (VEC_index (tree, tf->dest_array,q->index)); | |
809 | |
810 if (mod) | |
811 gimple_seq_add_seq (&q->repl_stmt, mod); | |
812 | |
813 x = gimple_build_goto (finlab); | |
814 gimple_seq_add_stmt (&q->repl_stmt, x); | |
815 } | |
816 | |
817 /* We want to transform | |
818 try { body; } catch { stuff; } | |
819 to | |
820 body; goto over; lab: stuff; over: | |
821 | |
822 TP is a GIMPLE_TRY node. LAB is the label that | |
823 should be placed before the second operand, or NULL. OVER is | |
824 an existing label that should be put at the exit, or NULL. */ | |
825 | |
826 static gimple_seq | |
827 frob_into_branch_around (gimple tp, tree lab, tree over) | |
828 { | |
829 gimple x; | |
830 gimple_seq cleanup, result; | |
831 | |
832 cleanup = gimple_try_cleanup (tp); | |
833 result = gimple_try_eval (tp); | |
834 | |
835 if (gimple_seq_may_fallthru (result)) | |
836 { | |
837 if (!over) | |
838 over = create_artificial_label (); | |
839 x = gimple_build_goto (over); | |
840 gimple_seq_add_stmt (&result, x); | |
841 } | |
842 | |
843 if (lab) | |
844 { | |
845 x = gimple_build_label (lab); | |
846 gimple_seq_add_stmt (&result, x); | |
847 } | |
848 | |
849 gimple_seq_add_seq (&result, cleanup); | |
850 | |
851 if (over) | |
852 { | |
853 x = gimple_build_label (over); | |
854 gimple_seq_add_stmt (&result, x); | |
855 } | |
856 return result; | |
857 } | |
858 | |
859 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T. | |
860 Make sure to record all new labels found. */ | |
861 | |
862 static gimple_seq | |
863 lower_try_finally_dup_block (gimple_seq seq, struct leh_state *outer_state) | |
864 { | |
865 gimple region = NULL; | |
866 gimple_seq new_seq; | |
867 | |
868 new_seq = copy_gimple_seq_and_replace_locals (seq); | |
869 | |
870 if (outer_state->tf) | |
871 region = outer_state->tf->try_finally_expr; | |
872 collect_finally_tree_1 (new_seq, region); | |
873 | |
874 return new_seq; | |
875 } | |
876 | |
877 /* A subroutine of lower_try_finally. Create a fallthru label for | |
878 the given try_finally state. The only tricky bit here is that | |
879 we have to make sure to record the label in our outer context. */ | |
880 | |
881 static tree | |
882 lower_try_finally_fallthru_label (struct leh_tf_state *tf) | |
883 { | |
884 tree label = tf->fallthru_label; | |
885 treemple temp; | |
886 | |
887 if (!label) | |
888 { | |
889 label = create_artificial_label (); | |
890 tf->fallthru_label = label; | |
891 if (tf->outer->tf) | |
892 { | |
893 temp.t = label; | |
894 record_in_finally_tree (temp, tf->outer->tf->try_finally_expr); | |
895 } | |
896 } | |
897 return label; | |
898 } | |
899 | |
900 /* A subroutine of lower_try_finally. If lang_protect_cleanup_actions | |
901 returns non-null, then the language requires that the exception path out | |
902 of a try_finally be treated specially. To wit: the code within the | |
903 finally block may not itself throw an exception. We have two choices here. | |
904 First we can duplicate the finally block and wrap it in a must_not_throw | |
905 region. Second, we can generate code like | |
906 | |
907 try { | |
908 finally_block; | |
909 } catch { | |
910 if (fintmp == eh_edge) | |
911 protect_cleanup_actions; | |
912 } | |
913 | |
914 where "fintmp" is the temporary used in the switch statement generation | |
915 alternative considered below. For the nonce, we always choose the first | |
916 option. | |
917 | |
918 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */ | |
919 | |
920 static void | |
921 honor_protect_cleanup_actions (struct leh_state *outer_state, | |
922 struct leh_state *this_state, | |
923 struct leh_tf_state *tf) | |
924 { | |
925 gimple protect_cleanup_actions; | |
926 gimple_stmt_iterator gsi; | |
927 bool finally_may_fallthru; | |
928 gimple_seq finally; | |
929 gimple x; | |
930 | |
931 /* First check for nothing to do. */ | |
932 if (lang_protect_cleanup_actions) | |
933 protect_cleanup_actions = lang_protect_cleanup_actions (); | |
934 else | |
935 protect_cleanup_actions = NULL; | |
936 | |
937 finally = gimple_try_cleanup (tf->top_p); | |
938 | |
939 /* If the EH case of the finally block can fall through, this may be a | |
940 structure of the form | |
941 try { | |
942 try { | |
943 throw ...; | |
944 } cleanup { | |
945 try { | |
946 throw ...; | |
947 } catch (...) { | |
948 } | |
949 } | |
950 } catch (...) { | |
951 yyy; | |
952 } | |
953 E.g. with an inline destructor with an embedded try block. In this | |
954 case we must save the runtime EH data around the nested exception. | |
955 | |
956 This complication means that any time the previous runtime data might | |
957 be used (via fallthru from the finally) we handle the eh case here, | |
958 whether or not protect_cleanup_actions is active. */ | |
959 | |
960 finally_may_fallthru = gimple_seq_may_fallthru (finally); | |
961 if (!finally_may_fallthru && !protect_cleanup_actions) | |
962 return; | |
963 | |
964 /* Duplicate the FINALLY block. Only need to do this for try-finally, | |
965 and not for cleanups. */ | |
966 if (this_state) | |
967 finally = lower_try_finally_dup_block (finally, outer_state); | |
968 | |
969 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP | |
970 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought | |
971 to be in an enclosing scope, but needs to be implemented at this level | |
972 to avoid a nesting violation (see wrap_temporary_cleanups in | |
973 cp/decl.c). Since it's logically at an outer level, we should call | |
974 terminate before we get to it, so strip it away before adding the | |
975 MUST_NOT_THROW filter. */ | |
976 gsi = gsi_start (finally); | |
977 x = gsi_stmt (gsi); | |
978 if (protect_cleanup_actions | |
979 && gimple_code (x) == GIMPLE_TRY | |
980 && gimple_try_kind (x) == GIMPLE_TRY_CATCH | |
981 && gimple_try_catch_is_cleanup (x)) | |
982 { | |
983 gsi_insert_seq_before (&gsi, gimple_try_eval (x), GSI_SAME_STMT); | |
984 gsi_remove (&gsi, false); | |
985 } | |
986 | |
987 /* Resume execution after the exception. Adding this now lets | |
988 lower_eh_filter not add unnecessary gotos, as it is clear that | |
989 we never fallthru from this copy of the finally block. */ | |
990 if (finally_may_fallthru) | |
991 { | |
992 tree save_eptr, save_filt; | |
993 tree tmp; | |
994 | |
995 save_eptr = create_tmp_var (ptr_type_node, "save_eptr"); | |
996 save_filt = create_tmp_var (integer_type_node, "save_filt"); | |
997 | |
998 gsi = gsi_start (finally); | |
999 tmp = build0 (EXC_PTR_EXPR, ptr_type_node); | |
1000 x = gimple_build_assign (save_eptr, tmp); | |
1001 gsi_insert_before (&gsi, x, GSI_CONTINUE_LINKING); | |
1002 | |
1003 tmp = build0 (FILTER_EXPR, integer_type_node); | |
1004 x = gimple_build_assign (save_filt, tmp); | |
1005 gsi_insert_before (&gsi, x, GSI_CONTINUE_LINKING); | |
1006 | |
1007 gsi = gsi_last (finally); | |
1008 tmp = build0 (EXC_PTR_EXPR, ptr_type_node); | |
1009 x = gimple_build_assign (tmp, save_eptr); | |
1010 gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); | |
1011 | |
1012 tmp = build0 (FILTER_EXPR, integer_type_node); | |
1013 x = gimple_build_assign (tmp, save_filt); | |
1014 gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); | |
1015 | |
1016 x = gimple_build_resx (get_eh_region_number (tf->region)); | |
1017 gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); | |
1018 } | |
1019 | |
1020 /* Wrap the block with protect_cleanup_actions as the action. */ | |
1021 if (protect_cleanup_actions) | |
1022 { | |
1023 gimple_seq seq = NULL, failure = NULL; | |
1024 | |
1025 gimple_seq_add_stmt (&failure, protect_cleanup_actions); | |
1026 x = gimple_build_eh_filter (NULL, failure); | |
1027 gimple_eh_filter_set_must_not_throw (x, 1); | |
1028 | |
1029 gimple_seq_add_stmt (&seq, x); | |
1030 x = gimple_build_try (finally, seq, GIMPLE_TRY_CATCH); | |
1031 finally = lower_eh_filter (outer_state, x); | |
1032 } | |
1033 else | |
1034 lower_eh_constructs_1 (outer_state, finally); | |
1035 | |
1036 /* Hook this up to the end of the existing try block. If we | |
1037 previously fell through the end, we'll have to branch around. | |
1038 This means adding a new goto, and adding it to the queue. */ | |
1039 | |
1040 gsi = gsi_last (gimple_try_eval (tf->top_p)); | |
1041 | |
1042 if (tf->may_fallthru) | |
1043 { | |
1044 tree tmp; | |
1045 tmp = lower_try_finally_fallthru_label (tf); | |
1046 x = gimple_build_goto (tmp); | |
1047 gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); | |
1048 | |
1049 if (this_state) | |
1050 maybe_record_in_goto_queue (this_state, x); | |
1051 | |
1052 tf->may_fallthru = false; | |
1053 } | |
1054 | |
1055 x = gimple_build_label (tf->eh_label); | |
1056 gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); | |
1057 gsi_insert_seq_after (&gsi, finally, GSI_CONTINUE_LINKING); | |
1058 | |
1059 /* Having now been handled, EH isn't to be considered with | |
1060 the rest of the outgoing edges. */ | |
1061 tf->may_throw = false; | |
1062 } | |
1063 | |
1064 /* A subroutine of lower_try_finally. We have determined that there is | |
1065 no fallthru edge out of the finally block. This means that there is | |
1066 no outgoing edge corresponding to any incoming edge. Restructure the | |
1067 try_finally node for this special case. */ | |
1068 | |
1069 static void | |
1070 lower_try_finally_nofallthru (struct leh_state *state, | |
1071 struct leh_tf_state *tf) | |
1072 { | |
1073 tree lab, return_val; | |
1074 gimple x; | |
1075 gimple_seq finally; | |
1076 struct goto_queue_node *q, *qe; | |
1077 | |
1078 if (tf->may_throw) | |
1079 lab = tf->eh_label; | |
1080 else | |
1081 lab = create_artificial_label (); | |
1082 | |
1083 /* We expect that tf->top_p is a GIMPLE_TRY. */ | |
1084 finally = gimple_try_cleanup (tf->top_p); | |
1085 tf->top_p_seq = gimple_try_eval (tf->top_p); | |
1086 | |
1087 x = gimple_build_label (lab); | |
1088 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1089 | |
1090 return_val = NULL; | |
1091 q = tf->goto_queue; | |
1092 qe = q + tf->goto_queue_active; | |
1093 for (; q < qe; ++q) | |
1094 if (q->index < 0) | |
1095 do_return_redirection (q, lab, NULL, &return_val); | |
1096 else | |
1097 do_goto_redirection (q, lab, NULL, tf); | |
1098 | |
1099 replace_goto_queue (tf); | |
1100 | |
1101 lower_eh_constructs_1 (state, finally); | |
1102 gimple_seq_add_seq (&tf->top_p_seq, finally); | |
1103 } | |
1104 | |
1105 /* A subroutine of lower_try_finally. We have determined that there is | |
1106 exactly one destination of the finally block. Restructure the | |
1107 try_finally node for this special case. */ | |
1108 | |
1109 static void | |
1110 lower_try_finally_onedest (struct leh_state *state, struct leh_tf_state *tf) | |
1111 { | |
1112 struct goto_queue_node *q, *qe; | |
1113 gimple x; | |
1114 gimple_seq finally; | |
1115 tree finally_label; | |
1116 | |
1117 finally = gimple_try_cleanup (tf->top_p); | |
1118 tf->top_p_seq = gimple_try_eval (tf->top_p); | |
1119 | |
1120 lower_eh_constructs_1 (state, finally); | |
1121 | |
1122 if (tf->may_throw) | |
1123 { | |
1124 /* Only reachable via the exception edge. Add the given label to | |
1125 the head of the FINALLY block. Append a RESX at the end. */ | |
1126 | |
1127 x = gimple_build_label (tf->eh_label); | |
1128 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1129 | |
1130 gimple_seq_add_seq (&tf->top_p_seq, finally); | |
1131 | |
1132 x = gimple_build_resx (get_eh_region_number (tf->region)); | |
1133 | |
1134 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1135 | |
1136 return; | |
1137 } | |
1138 | |
1139 if (tf->may_fallthru) | |
1140 { | |
1141 /* Only reachable via the fallthru edge. Do nothing but let | |
1142 the two blocks run together; we'll fall out the bottom. */ | |
1143 gimple_seq_add_seq (&tf->top_p_seq, finally); | |
1144 return; | |
1145 } | |
1146 | |
1147 finally_label = create_artificial_label (); | |
1148 x = gimple_build_label (finally_label); | |
1149 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1150 | |
1151 gimple_seq_add_seq (&tf->top_p_seq, finally); | |
1152 | |
1153 q = tf->goto_queue; | |
1154 qe = q + tf->goto_queue_active; | |
1155 | |
1156 if (tf->may_return) | |
1157 { | |
1158 /* Reachable by return expressions only. Redirect them. */ | |
1159 tree return_val = NULL; | |
1160 for (; q < qe; ++q) | |
1161 do_return_redirection (q, finally_label, NULL, &return_val); | |
1162 replace_goto_queue (tf); | |
1163 } | |
1164 else | |
1165 { | |
1166 /* Reachable by goto expressions only. Redirect them. */ | |
1167 for (; q < qe; ++q) | |
1168 do_goto_redirection (q, finally_label, NULL, tf); | |
1169 replace_goto_queue (tf); | |
1170 | |
1171 if (VEC_index (tree, tf->dest_array, 0) == tf->fallthru_label) | |
1172 { | |
1173 /* Reachable by goto to fallthru label only. Redirect it | |
1174 to the new label (already created, sadly), and do not | |
1175 emit the final branch out, or the fallthru label. */ | |
1176 tf->fallthru_label = NULL; | |
1177 return; | |
1178 } | |
1179 } | |
1180 | |
1181 /* Place the original return/goto to the original destination | |
1182 immediately after the finally block. */ | |
1183 x = tf->goto_queue[0].cont_stmt; | |
1184 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1185 maybe_record_in_goto_queue (state, x); | |
1186 } | |
1187 | |
1188 /* A subroutine of lower_try_finally. There are multiple edges incoming | |
1189 and outgoing from the finally block. Implement this by duplicating the | |
1190 finally block for every destination. */ | |
1191 | |
1192 static void | |
1193 lower_try_finally_copy (struct leh_state *state, struct leh_tf_state *tf) | |
1194 { | |
1195 gimple_seq finally; | |
1196 gimple_seq new_stmt; | |
1197 gimple_seq seq; | |
1198 gimple x; | |
1199 tree tmp; | |
1200 | |
1201 finally = gimple_try_cleanup (tf->top_p); | |
1202 tf->top_p_seq = gimple_try_eval (tf->top_p); | |
1203 new_stmt = NULL; | |
1204 | |
1205 if (tf->may_fallthru) | |
1206 { | |
1207 seq = lower_try_finally_dup_block (finally, state); | |
1208 lower_eh_constructs_1 (state, seq); | |
1209 gimple_seq_add_seq (&new_stmt, seq); | |
1210 | |
1211 tmp = lower_try_finally_fallthru_label (tf); | |
1212 x = gimple_build_goto (tmp); | |
1213 gimple_seq_add_stmt (&new_stmt, x); | |
1214 } | |
1215 | |
1216 if (tf->may_throw) | |
1217 { | |
1218 x = gimple_build_label (tf->eh_label); | |
1219 gimple_seq_add_stmt (&new_stmt, x); | |
1220 | |
1221 seq = lower_try_finally_dup_block (finally, state); | |
1222 lower_eh_constructs_1 (state, seq); | |
1223 gimple_seq_add_seq (&new_stmt, seq); | |
1224 | |
1225 x = gimple_build_resx (get_eh_region_number (tf->region)); | |
1226 gimple_seq_add_stmt (&new_stmt, x); | |
1227 } | |
1228 | |
1229 if (tf->goto_queue) | |
1230 { | |
1231 struct goto_queue_node *q, *qe; | |
1232 tree return_val = NULL; | |
1233 int return_index, index; | |
1234 struct labels_s | |
1235 { | |
1236 struct goto_queue_node *q; | |
1237 tree label; | |
1238 } *labels; | |
1239 | |
1240 return_index = VEC_length (tree, tf->dest_array); | |
1241 labels = XCNEWVEC (struct labels_s, return_index + 1); | |
1242 | |
1243 q = tf->goto_queue; | |
1244 qe = q + tf->goto_queue_active; | |
1245 for (; q < qe; q++) | |
1246 { | |
1247 index = q->index < 0 ? return_index : q->index; | |
1248 | |
1249 if (!labels[index].q) | |
1250 labels[index].q = q; | |
1251 } | |
1252 | |
1253 for (index = 0; index < return_index + 1; index++) | |
1254 { | |
1255 tree lab; | |
1256 | |
1257 q = labels[index].q; | |
1258 if (! q) | |
1259 continue; | |
1260 | |
1261 lab = labels[index].label = create_artificial_label (); | |
1262 | |
1263 if (index == return_index) | |
1264 do_return_redirection (q, lab, NULL, &return_val); | |
1265 else | |
1266 do_goto_redirection (q, lab, NULL, tf); | |
1267 | |
1268 x = gimple_build_label (lab); | |
1269 gimple_seq_add_stmt (&new_stmt, x); | |
1270 | |
1271 seq = lower_try_finally_dup_block (finally, state); | |
1272 lower_eh_constructs_1 (state, seq); | |
1273 gimple_seq_add_seq (&new_stmt, seq); | |
1274 | |
1275 gimple_seq_add_stmt (&new_stmt, q->cont_stmt); | |
1276 maybe_record_in_goto_queue (state, q->cont_stmt); | |
1277 } | |
1278 | |
1279 for (q = tf->goto_queue; q < qe; q++) | |
1280 { | |
1281 tree lab; | |
1282 | |
1283 index = q->index < 0 ? return_index : q->index; | |
1284 | |
1285 if (labels[index].q == q) | |
1286 continue; | |
1287 | |
1288 lab = labels[index].label; | |
1289 | |
1290 if (index == return_index) | |
1291 do_return_redirection (q, lab, NULL, &return_val); | |
1292 else | |
1293 do_goto_redirection (q, lab, NULL, tf); | |
1294 } | |
1295 | |
1296 replace_goto_queue (tf); | |
1297 free (labels); | |
1298 } | |
1299 | |
1300 /* Need to link new stmts after running replace_goto_queue due | |
1301 to not wanting to process the same goto stmts twice. */ | |
1302 gimple_seq_add_seq (&tf->top_p_seq, new_stmt); | |
1303 } | |
1304 | |
1305 /* A subroutine of lower_try_finally. There are multiple edges incoming | |
1306 and outgoing from the finally block. Implement this by instrumenting | |
1307 each incoming edge and creating a switch statement at the end of the | |
1308 finally block that branches to the appropriate destination. */ | |
1309 | |
1310 static void | |
1311 lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf) | |
1312 { | |
1313 struct goto_queue_node *q, *qe; | |
1314 tree return_val = NULL; | |
1315 tree finally_tmp, finally_label; | |
1316 int return_index, eh_index, fallthru_index; | |
1317 int nlabels, ndests, j, last_case_index; | |
1318 tree last_case; | |
1319 VEC (tree,heap) *case_label_vec; | |
1320 gimple_seq switch_body; | |
1321 gimple x; | |
1322 tree tmp; | |
1323 gimple switch_stmt; | |
1324 gimple_seq finally; | |
1325 struct pointer_map_t *cont_map = NULL; | |
1326 | |
1327 switch_body = gimple_seq_alloc (); | |
1328 | |
1329 /* Mash the TRY block to the head of the chain. */ | |
1330 finally = gimple_try_cleanup (tf->top_p); | |
1331 tf->top_p_seq = gimple_try_eval (tf->top_p); | |
1332 | |
1333 /* Lower the finally block itself. */ | |
1334 lower_eh_constructs_1 (state, finally); | |
1335 | |
1336 /* Prepare for switch statement generation. */ | |
1337 nlabels = VEC_length (tree, tf->dest_array); | |
1338 return_index = nlabels; | |
1339 eh_index = return_index + tf->may_return; | |
1340 fallthru_index = eh_index + tf->may_throw; | |
1341 ndests = fallthru_index + tf->may_fallthru; | |
1342 | |
1343 finally_tmp = create_tmp_var (integer_type_node, "finally_tmp"); | |
1344 finally_label = create_artificial_label (); | |
1345 | |
1346 /* We use VEC_quick_push on case_label_vec throughout this function, | |
1347 since we know the size in advance and allocate precisely as muce | |
1348 space as needed. */ | |
1349 case_label_vec = VEC_alloc (tree, heap, ndests); | |
1350 last_case = NULL; | |
1351 last_case_index = 0; | |
1352 | |
1353 /* Begin inserting code for getting to the finally block. Things | |
1354 are done in this order to correspond to the sequence the code is | |
1355 layed out. */ | |
1356 | |
1357 if (tf->may_fallthru) | |
1358 { | |
1359 x = gimple_build_assign (finally_tmp, build_int_cst (integer_type_node, | |
1360 fallthru_index)); | |
1361 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1362 | |
1363 if (tf->may_throw) | |
1364 { | |
1365 x = gimple_build_goto (finally_label); | |
1366 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1367 } | |
1368 | |
1369 | |
1370 last_case = build3 (CASE_LABEL_EXPR, void_type_node, | |
1371 build_int_cst (NULL_TREE, fallthru_index), NULL, | |
1372 create_artificial_label ()); | |
1373 VEC_quick_push (tree, case_label_vec, last_case); | |
1374 last_case_index++; | |
1375 | |
1376 x = gimple_build_label (CASE_LABEL (last_case)); | |
1377 gimple_seq_add_stmt (&switch_body, x); | |
1378 | |
1379 tmp = lower_try_finally_fallthru_label (tf); | |
1380 x = gimple_build_goto (tmp); | |
1381 gimple_seq_add_stmt (&switch_body, x); | |
1382 } | |
1383 | |
1384 if (tf->may_throw) | |
1385 { | |
1386 x = gimple_build_label (tf->eh_label); | |
1387 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1388 | |
1389 x = gimple_build_assign (finally_tmp, build_int_cst (integer_type_node, | |
1390 eh_index)); | |
1391 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1392 | |
1393 last_case = build3 (CASE_LABEL_EXPR, void_type_node, | |
1394 build_int_cst (NULL_TREE, eh_index), NULL, | |
1395 create_artificial_label ()); | |
1396 VEC_quick_push (tree, case_label_vec, last_case); | |
1397 last_case_index++; | |
1398 | |
1399 x = gimple_build_label (CASE_LABEL (last_case)); | |
1400 gimple_seq_add_stmt (&switch_body, x); | |
1401 x = gimple_build_resx (get_eh_region_number (tf->region)); | |
1402 gimple_seq_add_stmt (&switch_body, x); | |
1403 } | |
1404 | |
1405 x = gimple_build_label (finally_label); | |
1406 gimple_seq_add_stmt (&tf->top_p_seq, x); | |
1407 | |
1408 gimple_seq_add_seq (&tf->top_p_seq, finally); | |
1409 | |
1410 /* Redirect each incoming goto edge. */ | |
1411 q = tf->goto_queue; | |
1412 qe = q + tf->goto_queue_active; | |
1413 j = last_case_index + tf->may_return; | |
1414 /* Prepare the assignments to finally_tmp that are executed upon the | |
1415 entrance through a particular edge. */ | |
1416 for (; q < qe; ++q) | |
1417 { | |
1418 gimple_seq mod; | |
1419 int switch_id; | |
1420 unsigned int case_index; | |
1421 | |
1422 mod = gimple_seq_alloc (); | |
1423 | |
1424 if (q->index < 0) | |
1425 { | |
1426 x = gimple_build_assign (finally_tmp, | |
1427 build_int_cst (integer_type_node, | |
1428 return_index)); | |
1429 gimple_seq_add_stmt (&mod, x); | |
1430 do_return_redirection (q, finally_label, mod, &return_val); | |
1431 switch_id = return_index; | |
1432 } | |
1433 else | |
1434 { | |
1435 x = gimple_build_assign (finally_tmp, | |
1436 build_int_cst (integer_type_node, q->index)); | |
1437 gimple_seq_add_stmt (&mod, x); | |
1438 do_goto_redirection (q, finally_label, mod, tf); | |
1439 switch_id = q->index; | |
1440 } | |
1441 | |
1442 case_index = j + q->index; | |
1443 if (VEC_length (tree, case_label_vec) <= case_index | |
1444 || !VEC_index (tree, case_label_vec, case_index)) | |
1445 { | |
1446 tree case_lab; | |
1447 void **slot; | |
1448 case_lab = build3 (CASE_LABEL_EXPR, void_type_node, | |
1449 build_int_cst (NULL_TREE, switch_id), NULL, | |
1450 NULL); | |
1451 /* We store the cont_stmt in the pointer map, so that we can recover | |
1452 it in the loop below. We don't create the new label while | |
1453 walking the goto_queue because pointers don't offer a stable | |
1454 order. */ | |
1455 if (!cont_map) | |
1456 cont_map = pointer_map_create (); | |
1457 slot = pointer_map_insert (cont_map, case_lab); | |
1458 *slot = q->cont_stmt; | |
1459 VEC_quick_push (tree, case_label_vec, case_lab); | |
1460 } | |
1461 } | |
1462 for (j = last_case_index; j < last_case_index + nlabels; j++) | |
1463 { | |
1464 tree label; | |
1465 gimple cont_stmt; | |
1466 void **slot; | |
1467 | |
1468 last_case = VEC_index (tree, case_label_vec, j); | |
1469 | |
1470 gcc_assert (last_case); | |
1471 gcc_assert (cont_map); | |
1472 | |
1473 slot = pointer_map_contains (cont_map, last_case); | |
1474 /* As the comment above suggests, CASE_LABEL (last_case) was just a | |
1475 placeholder, it does not store an actual label, yet. */ | |
1476 gcc_assert (slot); | |
1477 cont_stmt = *(gimple *) slot; | |
1478 | |
1479 label = create_artificial_label (); | |
1480 CASE_LABEL (last_case) = label; | |
1481 | |
1482 x = gimple_build_label (label); | |
1483 gimple_seq_add_stmt (&switch_body, x); | |
1484 gimple_seq_add_stmt (&switch_body, cont_stmt); | |
1485 maybe_record_in_goto_queue (state, cont_stmt); | |
1486 } | |
1487 if (cont_map) | |
1488 pointer_map_destroy (cont_map); | |
1489 | |
1490 replace_goto_queue (tf); | |
1491 | |
1492 /* Make sure that the last case is the default label, as one is required. | |
1493 Then sort the labels, which is also required in GIMPLE. */ | |
1494 CASE_LOW (last_case) = NULL; | |
1495 sort_case_labels (case_label_vec); | |
1496 | |
1497 /* Build the switch statement, setting last_case to be the default | |
1498 label. */ | |
1499 switch_stmt = gimple_build_switch_vec (finally_tmp, last_case, | |
1500 case_label_vec); | |
1501 | |
1502 /* Need to link SWITCH_STMT after running replace_goto_queue | |
1503 due to not wanting to process the same goto stmts twice. */ | |
1504 gimple_seq_add_stmt (&tf->top_p_seq, switch_stmt); | |
1505 gimple_seq_add_seq (&tf->top_p_seq, switch_body); | |
1506 } | |
1507 | |
1508 /* Decide whether or not we are going to duplicate the finally block. | |
1509 There are several considerations. | |
1510 | |
1511 First, if this is Java, then the finally block contains code | |
1512 written by the user. It has line numbers associated with it, | |
1513 so duplicating the block means it's difficult to set a breakpoint. | |
1514 Since controlling code generation via -g is verboten, we simply | |
1515 never duplicate code without optimization. | |
1516 | |
1517 Second, we'd like to prevent egregious code growth. One way to | |
1518 do this is to estimate the size of the finally block, multiply | |
1519 that by the number of copies we'd need to make, and compare against | |
1520 the estimate of the size of the switch machinery we'd have to add. */ | |
1521 | |
1522 static bool | |
1523 decide_copy_try_finally (int ndests, gimple_seq finally) | |
1524 { | |
1525 int f_estimate, sw_estimate; | |
1526 | |
1527 if (!optimize) | |
1528 return false; | |
1529 | |
1530 /* Finally estimate N times, plus N gotos. */ | |
1531 f_estimate = count_insns_seq (finally, &eni_size_weights); | |
1532 f_estimate = (f_estimate + 1) * ndests; | |
1533 | |
1534 /* Switch statement (cost 10), N variable assignments, N gotos. */ | |
1535 sw_estimate = 10 + 2 * ndests; | |
1536 | |
1537 /* Optimize for size clearly wants our best guess. */ | |
1538 if (optimize_function_for_size_p (cfun)) | |
1539 return f_estimate < sw_estimate; | |
1540 | |
1541 /* ??? These numbers are completely made up so far. */ | |
1542 if (optimize > 1) | |
1543 return f_estimate < 100 || f_estimate < sw_estimate * 2; | |
1544 else | |
1545 return f_estimate < 40 || f_estimate * 2 < sw_estimate * 3; | |
1546 } | |
1547 | |
1548 | |
1549 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes | |
1550 to a sequence of labels and blocks, plus the exception region trees | |
1551 that record all the magic. This is complicated by the need to | |
1552 arrange for the FINALLY block to be executed on all exits. */ | |
1553 | |
1554 static gimple_seq | |
1555 lower_try_finally (struct leh_state *state, gimple tp) | |
1556 { | |
1557 struct leh_tf_state this_tf; | |
1558 struct leh_state this_state; | |
1559 int ndests; | |
1560 | |
1561 /* Process the try block. */ | |
1562 | |
1563 memset (&this_tf, 0, sizeof (this_tf)); | |
1564 this_tf.try_finally_expr = tp; | |
1565 this_tf.top_p = tp; | |
1566 this_tf.outer = state; | |
1567 if (using_eh_for_cleanups_p) | |
1568 this_tf.region | |
1569 = gen_eh_region_cleanup (state->cur_region, state->prev_try); | |
1570 else | |
1571 this_tf.region = NULL; | |
1572 | |
1573 this_state.cur_region = this_tf.region; | |
1574 this_state.prev_try = state->prev_try; | |
1575 this_state.tf = &this_tf; | |
1576 | |
1577 lower_eh_constructs_1 (&this_state, gimple_try_eval(tp)); | |
1578 | |
1579 /* Determine if the try block is escaped through the bottom. */ | |
1580 this_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp)); | |
1581 | |
1582 /* Determine if any exceptions are possible within the try block. */ | |
1583 if (using_eh_for_cleanups_p) | |
1584 this_tf.may_throw = get_eh_region_may_contain_throw (this_tf.region); | |
1585 if (this_tf.may_throw) | |
1586 { | |
1587 this_tf.eh_label = create_artificial_label (); | |
1588 set_eh_region_tree_label (this_tf.region, this_tf.eh_label); | |
1589 honor_protect_cleanup_actions (state, &this_state, &this_tf); | |
1590 } | |
1591 | |
1592 /* Determine how many edges (still) reach the finally block. Or rather, | |
1593 how many destinations are reached by the finally block. Use this to | |
1594 determine how we process the finally block itself. */ | |
1595 | |
1596 ndests = VEC_length (tree, this_tf.dest_array); | |
1597 ndests += this_tf.may_fallthru; | |
1598 ndests += this_tf.may_return; | |
1599 ndests += this_tf.may_throw; | |
1600 | |
1601 /* If the FINALLY block is not reachable, dike it out. */ | |
1602 if (ndests == 0) | |
1603 { | |
1604 gimple_seq_add_seq (&this_tf.top_p_seq, gimple_try_eval (tp)); | |
1605 gimple_try_set_cleanup (tp, NULL); | |
1606 } | |
1607 /* If the finally block doesn't fall through, then any destination | |
1608 we might try to impose there isn't reached either. There may be | |
1609 some minor amount of cleanup and redirection still needed. */ | |
1610 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp))) | |
1611 lower_try_finally_nofallthru (state, &this_tf); | |
1612 | |
1613 /* We can easily special-case redirection to a single destination. */ | |
1614 else if (ndests == 1) | |
1615 lower_try_finally_onedest (state, &this_tf); | |
1616 else if (decide_copy_try_finally (ndests, gimple_try_cleanup (tp))) | |
1617 lower_try_finally_copy (state, &this_tf); | |
1618 else | |
1619 lower_try_finally_switch (state, &this_tf); | |
1620 | |
1621 /* If someone requested we add a label at the end of the transformed | |
1622 block, do so. */ | |
1623 if (this_tf.fallthru_label) | |
1624 { | |
1625 /* This must be reached only if ndests == 0. */ | |
1626 gimple x = gimple_build_label (this_tf.fallthru_label); | |
1627 gimple_seq_add_stmt (&this_tf.top_p_seq, x); | |
1628 } | |
1629 | |
1630 VEC_free (tree, heap, this_tf.dest_array); | |
1631 if (this_tf.goto_queue) | |
1632 free (this_tf.goto_queue); | |
1633 if (this_tf.goto_queue_map) | |
1634 pointer_map_destroy (this_tf.goto_queue_map); | |
1635 | |
1636 return this_tf.top_p_seq; | |
1637 } | |
1638 | |
1639 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a | |
1640 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the | |
1641 exception region trees that records all the magic. */ | |
1642 | |
1643 static gimple_seq | |
1644 lower_catch (struct leh_state *state, gimple tp) | |
1645 { | |
1646 struct eh_region *try_region; | |
1647 struct leh_state this_state; | |
1648 gimple_stmt_iterator gsi; | |
1649 tree out_label; | |
1650 | |
1651 try_region = gen_eh_region_try (state->cur_region); | |
1652 this_state.cur_region = try_region; | |
1653 this_state.prev_try = try_region; | |
1654 this_state.tf = state->tf; | |
1655 | |
1656 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp)); | |
1657 | |
1658 if (!get_eh_region_may_contain_throw (try_region)) | |
1659 { | |
1660 return gimple_try_eval (tp); | |
1661 } | |
1662 | |
1663 out_label = NULL; | |
1664 for (gsi = gsi_start (gimple_try_cleanup (tp)); !gsi_end_p (gsi); ) | |
1665 { | |
1666 struct eh_region *catch_region; | |
1667 tree eh_label; | |
1668 gimple x, gcatch; | |
1669 | |
1670 gcatch = gsi_stmt (gsi); | |
1671 catch_region = gen_eh_region_catch (try_region, | |
1672 gimple_catch_types (gcatch)); | |
1673 | |
1674 this_state.cur_region = catch_region; | |
1675 this_state.prev_try = state->prev_try; | |
1676 lower_eh_constructs_1 (&this_state, gimple_catch_handler (gcatch)); | |
1677 | |
1678 eh_label = create_artificial_label (); | |
1679 set_eh_region_tree_label (catch_region, eh_label); | |
1680 | |
1681 x = gimple_build_label (eh_label); | |
1682 gsi_insert_before (&gsi, x, GSI_SAME_STMT); | |
1683 | |
1684 if (gimple_seq_may_fallthru (gimple_catch_handler (gcatch))) | |
1685 { | |
1686 if (!out_label) | |
1687 out_label = create_artificial_label (); | |
1688 | |
1689 x = gimple_build_goto (out_label); | |
1690 gimple_seq_add_stmt (gimple_catch_handler_ptr (gcatch), x); | |
1691 } | |
1692 | |
1693 gsi_insert_seq_before (&gsi, gimple_catch_handler (gcatch), | |
1694 GSI_SAME_STMT); | |
1695 gsi_remove (&gsi, false); | |
1696 } | |
1697 | |
1698 return frob_into_branch_around (tp, NULL, out_label); | |
1699 } | |
1700 | |
1701 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a | |
1702 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception | |
1703 region trees that record all the magic. */ | |
1704 | |
1705 static gimple_seq | |
1706 lower_eh_filter (struct leh_state *state, gimple tp) | |
1707 { | |
1708 struct leh_state this_state; | |
1709 struct eh_region *this_region; | |
1710 gimple inner; | |
1711 tree eh_label; | |
1712 | |
1713 inner = gimple_seq_first_stmt (gimple_try_cleanup (tp)); | |
1714 | |
1715 if (gimple_eh_filter_must_not_throw (inner)) | |
1716 this_region = gen_eh_region_must_not_throw (state->cur_region); | |
1717 else | |
1718 this_region = gen_eh_region_allowed (state->cur_region, | |
1719 gimple_eh_filter_types (inner)); | |
1720 this_state = *state; | |
1721 this_state.cur_region = this_region; | |
1722 /* For must not throw regions any cleanup regions inside it | |
1723 can't reach outer catch regions. */ | |
1724 if (gimple_eh_filter_must_not_throw (inner)) | |
1725 this_state.prev_try = NULL; | |
1726 | |
1727 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp)); | |
1728 | |
1729 if (!get_eh_region_may_contain_throw (this_region)) | |
1730 { | |
1731 return gimple_try_eval (tp); | |
1732 } | |
1733 | |
1734 lower_eh_constructs_1 (state, gimple_eh_filter_failure (inner)); | |
1735 gimple_try_set_cleanup (tp, gimple_eh_filter_failure (inner)); | |
1736 | |
1737 eh_label = create_artificial_label (); | |
1738 set_eh_region_tree_label (this_region, eh_label); | |
1739 | |
1740 return frob_into_branch_around (tp, eh_label, NULL); | |
1741 } | |
1742 | |
1743 /* Implement a cleanup expression. This is similar to try-finally, | |
1744 except that we only execute the cleanup block for exception edges. */ | |
1745 | |
1746 static gimple_seq | |
1747 lower_cleanup (struct leh_state *state, gimple tp) | |
1748 { | |
1749 struct leh_state this_state; | |
1750 struct eh_region *this_region; | |
1751 struct leh_tf_state fake_tf; | |
1752 gimple_seq result; | |
1753 | |
1754 /* If not using eh, then exception-only cleanups are no-ops. */ | |
1755 if (!flag_exceptions) | |
1756 { | |
1757 result = gimple_try_eval (tp); | |
1758 lower_eh_constructs_1 (state, result); | |
1759 return result; | |
1760 } | |
1761 | |
1762 this_region = gen_eh_region_cleanup (state->cur_region, state->prev_try); | |
1763 this_state = *state; | |
1764 this_state.cur_region = this_region; | |
1765 | |
1766 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp)); | |
1767 | |
1768 if (!get_eh_region_may_contain_throw (this_region)) | |
1769 { | |
1770 return gimple_try_eval (tp); | |
1771 } | |
1772 | |
1773 /* Build enough of a try-finally state so that we can reuse | |
1774 honor_protect_cleanup_actions. */ | |
1775 memset (&fake_tf, 0, sizeof (fake_tf)); | |
1776 fake_tf.top_p = tp; | |
1777 fake_tf.outer = state; | |
1778 fake_tf.region = this_region; | |
1779 fake_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp)); | |
1780 fake_tf.may_throw = true; | |
1781 | |
1782 fake_tf.eh_label = create_artificial_label (); | |
1783 set_eh_region_tree_label (this_region, fake_tf.eh_label); | |
1784 | |
1785 honor_protect_cleanup_actions (state, NULL, &fake_tf); | |
1786 | |
1787 if (fake_tf.may_throw) | |
1788 { | |
1789 /* In this case honor_protect_cleanup_actions had nothing to do, | |
1790 and we should process this normally. */ | |
1791 lower_eh_constructs_1 (state, gimple_try_cleanup (tp)); | |
1792 result = frob_into_branch_around (tp, fake_tf.eh_label, | |
1793 fake_tf.fallthru_label); | |
1794 } | |
1795 else | |
1796 { | |
1797 /* In this case honor_protect_cleanup_actions did nearly all of | |
1798 the work. All we have left is to append the fallthru_label. */ | |
1799 | |
1800 result = gimple_try_eval (tp); | |
1801 if (fake_tf.fallthru_label) | |
1802 { | |
1803 gimple x = gimple_build_label (fake_tf.fallthru_label); | |
1804 gimple_seq_add_stmt (&result, x); | |
1805 } | |
1806 } | |
1807 return result; | |
1808 } | |
1809 | |
1810 | |
1811 | |
1812 /* Main loop for lowering eh constructs. Also moves gsi to the next | |
1813 statement. */ | |
1814 | |
1815 static void | |
1816 lower_eh_constructs_2 (struct leh_state *state, gimple_stmt_iterator *gsi) | |
1817 { | |
1818 gimple_seq replace; | |
1819 gimple x; | |
1820 gimple stmt = gsi_stmt (*gsi); | |
1821 | |
1822 switch (gimple_code (stmt)) | |
1823 { | |
1824 case GIMPLE_CALL: | |
1825 case GIMPLE_ASSIGN: | |
1826 /* Look for things that can throw exceptions, and record them. */ | |
1827 if (state->cur_region && stmt_could_throw_p (stmt)) | |
1828 { | |
1829 record_stmt_eh_region (state->cur_region, stmt); | |
1830 note_eh_region_may_contain_throw (state->cur_region); | |
1831 } | |
1832 break; | |
1833 | |
1834 case GIMPLE_COND: | |
1835 case GIMPLE_GOTO: | |
1836 case GIMPLE_RETURN: | |
1837 maybe_record_in_goto_queue (state, stmt); | |
1838 break; | |
1839 | |
1840 case GIMPLE_SWITCH: | |
1841 verify_norecord_switch_expr (state, stmt); | |
1842 break; | |
1843 | |
1844 case GIMPLE_TRY: | |
1845 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY) | |
1846 replace = lower_try_finally (state, stmt); | |
1847 else | |
1848 { | |
1849 x = gimple_seq_first_stmt (gimple_try_cleanup (stmt)); | |
1850 switch (gimple_code (x)) | |
1851 { | |
1852 case GIMPLE_CATCH: | |
1853 replace = lower_catch (state, stmt); | |
1854 break; | |
1855 case GIMPLE_EH_FILTER: | |
1856 replace = lower_eh_filter (state, stmt); | |
1857 break; | |
1858 default: | |
1859 replace = lower_cleanup (state, stmt); | |
1860 break; | |
1861 } | |
1862 } | |
1863 | |
1864 /* Remove the old stmt and insert the transformed sequence | |
1865 instead. */ | |
1866 gsi_insert_seq_before (gsi, replace, GSI_SAME_STMT); | |
1867 gsi_remove (gsi, true); | |
1868 | |
1869 /* Return since we don't want gsi_next () */ | |
1870 return; | |
1871 | |
1872 default: | |
1873 /* A type, a decl, or some kind of statement that we're not | |
1874 interested in. Don't walk them. */ | |
1875 break; | |
1876 } | |
1877 | |
1878 gsi_next (gsi); | |
1879 } | |
1880 | |
1881 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */ | |
1882 | |
1883 static void | |
1884 lower_eh_constructs_1 (struct leh_state *state, gimple_seq seq) | |
1885 { | |
1886 gimple_stmt_iterator gsi; | |
1887 for (gsi = gsi_start (seq); !gsi_end_p (gsi);) | |
1888 lower_eh_constructs_2 (state, &gsi); | |
1889 } | |
1890 | |
1891 static unsigned int | |
1892 lower_eh_constructs (void) | |
1893 { | |
1894 struct leh_state null_state; | |
1895 | |
1896 gimple_seq bodyp = gimple_body (current_function_decl); | |
1897 | |
1898 finally_tree = htab_create (31, struct_ptr_hash, struct_ptr_eq, free); | |
1899 | |
1900 collect_finally_tree_1 (bodyp, NULL); | |
1901 | |
1902 memset (&null_state, 0, sizeof (null_state)); | |
1903 lower_eh_constructs_1 (&null_state, bodyp); | |
1904 | |
1905 htab_delete (finally_tree); | |
1906 | |
1907 collect_eh_region_array (); | |
1908 return 0; | |
1909 } | |
1910 | |
1911 struct gimple_opt_pass pass_lower_eh = | |
1912 { | |
1913 { | |
1914 GIMPLE_PASS, | |
1915 "eh", /* name */ | |
1916 NULL, /* gate */ | |
1917 lower_eh_constructs, /* execute */ | |
1918 NULL, /* sub */ | |
1919 NULL, /* next */ | |
1920 0, /* static_pass_number */ | |
1921 TV_TREE_EH, /* tv_id */ | |
1922 PROP_gimple_lcf, /* properties_required */ | |
1923 PROP_gimple_leh, /* properties_provided */ | |
1924 0, /* properties_destroyed */ | |
1925 0, /* todo_flags_start */ | |
1926 TODO_dump_func /* todo_flags_finish */ | |
1927 } | |
1928 }; | |
1929 | |
1930 | |
1931 /* Construct EH edges for STMT. */ | |
1932 | |
1933 static void | |
1934 make_eh_edge (struct eh_region *region, void *data) | |
1935 { | |
1936 gimple stmt; | |
1937 tree lab; | |
1938 basic_block src, dst; | |
1939 | |
1940 stmt = (gimple) data; | |
1941 lab = get_eh_region_tree_label (region); | |
1942 | |
1943 src = gimple_bb (stmt); | |
1944 dst = label_to_block (lab); | |
1945 | |
1946 make_edge (src, dst, EDGE_ABNORMAL | EDGE_EH); | |
1947 } | |
1948 | |
1949 void | |
1950 make_eh_edges (gimple stmt) | |
1951 { | |
1952 int region_nr; | |
1953 bool is_resx; | |
1954 | |
1955 if (gimple_code (stmt) == GIMPLE_RESX) | |
1956 { | |
1957 region_nr = gimple_resx_region (stmt); | |
1958 is_resx = true; | |
1959 } | |
1960 else | |
1961 { | |
1962 region_nr = lookup_stmt_eh_region (stmt); | |
1963 if (region_nr < 0) | |
1964 return; | |
1965 is_resx = false; | |
1966 } | |
1967 | |
1968 foreach_reachable_handler (region_nr, is_resx, make_eh_edge, stmt); | |
1969 } | |
1970 | |
1971 static bool mark_eh_edge_found_error; | |
1972 | |
1973 /* Mark edge make_eh_edge would create for given region by setting it aux | |
1974 field, output error if something goes wrong. */ | |
1975 | |
1976 static void | |
1977 mark_eh_edge (struct eh_region *region, void *data) | |
1978 { | |
1979 gimple stmt; | |
1980 tree lab; | |
1981 basic_block src, dst; | |
1982 edge e; | |
1983 | |
1984 stmt = (gimple) data; | |
1985 lab = get_eh_region_tree_label (region); | |
1986 | |
1987 src = gimple_bb (stmt); | |
1988 dst = label_to_block (lab); | |
1989 | |
1990 e = find_edge (src, dst); | |
1991 if (!e) | |
1992 { | |
1993 error ("EH edge %i->%i is missing", src->index, dst->index); | |
1994 mark_eh_edge_found_error = true; | |
1995 } | |
1996 else if (!(e->flags & EDGE_EH)) | |
1997 { | |
1998 error ("EH edge %i->%i miss EH flag", src->index, dst->index); | |
1999 mark_eh_edge_found_error = true; | |
2000 } | |
2001 else if (e->aux) | |
2002 { | |
2003 /* ??? might not be mistake. */ | |
2004 error ("EH edge %i->%i has duplicated regions", src->index, dst->index); | |
2005 mark_eh_edge_found_error = true; | |
2006 } | |
2007 else | |
2008 e->aux = (void *)1; | |
2009 } | |
2010 | |
2011 /* Verify that BB containing STMT as the last statement, has precisely the | |
2012 edges that make_eh_edges would create. */ | |
2013 | |
2014 bool | |
2015 verify_eh_edges (gimple stmt) | |
2016 { | |
2017 int region_nr; | |
2018 bool is_resx; | |
2019 basic_block bb = gimple_bb (stmt); | |
2020 edge_iterator ei; | |
2021 edge e; | |
2022 | |
2023 FOR_EACH_EDGE (e, ei, bb->succs) | |
2024 gcc_assert (!e->aux); | |
2025 mark_eh_edge_found_error = false; | |
2026 if (gimple_code (stmt) == GIMPLE_RESX) | |
2027 { | |
2028 region_nr = gimple_resx_region (stmt); | |
2029 is_resx = true; | |
2030 } | |
2031 else | |
2032 { | |
2033 region_nr = lookup_stmt_eh_region (stmt); | |
2034 if (region_nr < 0) | |
2035 { | |
2036 FOR_EACH_EDGE (e, ei, bb->succs) | |
2037 if (e->flags & EDGE_EH) | |
2038 { | |
2039 error ("BB %i can not throw but has EH edges", bb->index); | |
2040 return true; | |
2041 } | |
2042 return false; | |
2043 } | |
2044 if (!stmt_could_throw_p (stmt)) | |
2045 { | |
2046 error ("BB %i last statement has incorrectly set region", bb->index); | |
2047 return true; | |
2048 } | |
2049 is_resx = false; | |
2050 } | |
2051 | |
2052 foreach_reachable_handler (region_nr, is_resx, mark_eh_edge, stmt); | |
2053 FOR_EACH_EDGE (e, ei, bb->succs) | |
2054 { | |
2055 if ((e->flags & EDGE_EH) && !e->aux) | |
2056 { | |
2057 error ("unnecessary EH edge %i->%i", bb->index, e->dest->index); | |
2058 mark_eh_edge_found_error = true; | |
2059 return true; | |
2060 } | |
2061 e->aux = NULL; | |
2062 } | |
2063 | |
2064 return mark_eh_edge_found_error; | |
2065 } | |
2066 | |
2067 | |
2068 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */ | |
2069 | |
2070 bool | |
2071 operation_could_trap_helper_p (enum tree_code op, | |
2072 bool fp_operation, | |
2073 bool honor_trapv, | |
2074 bool honor_nans, | |
2075 bool honor_snans, | |
2076 tree divisor, | |
2077 bool *handled) | |
2078 { | |
2079 *handled = true; | |
2080 switch (op) | |
2081 { | |
2082 case TRUNC_DIV_EXPR: | |
2083 case CEIL_DIV_EXPR: | |
2084 case FLOOR_DIV_EXPR: | |
2085 case ROUND_DIV_EXPR: | |
2086 case EXACT_DIV_EXPR: | |
2087 case CEIL_MOD_EXPR: | |
2088 case FLOOR_MOD_EXPR: | |
2089 case ROUND_MOD_EXPR: | |
2090 case TRUNC_MOD_EXPR: | |
2091 case RDIV_EXPR: | |
2092 if (honor_snans || honor_trapv) | |
2093 return true; | |
2094 if (fp_operation) | |
2095 return flag_trapping_math; | |
2096 if (!TREE_CONSTANT (divisor) || integer_zerop (divisor)) | |
2097 return true; | |
2098 return false; | |
2099 | |
2100 case LT_EXPR: | |
2101 case LE_EXPR: | |
2102 case GT_EXPR: | |
2103 case GE_EXPR: | |
2104 case LTGT_EXPR: | |
2105 /* Some floating point comparisons may trap. */ | |
2106 return honor_nans; | |
2107 | |
2108 case EQ_EXPR: | |
2109 case NE_EXPR: | |
2110 case UNORDERED_EXPR: | |
2111 case ORDERED_EXPR: | |
2112 case UNLT_EXPR: | |
2113 case UNLE_EXPR: | |
2114 case UNGT_EXPR: | |
2115 case UNGE_EXPR: | |
2116 case UNEQ_EXPR: | |
2117 return honor_snans; | |
2118 | |
2119 case CONVERT_EXPR: | |
2120 case FIX_TRUNC_EXPR: | |
2121 /* Conversion of floating point might trap. */ | |
2122 return honor_nans; | |
2123 | |
2124 case NEGATE_EXPR: | |
2125 case ABS_EXPR: | |
2126 case CONJ_EXPR: | |
2127 /* These operations don't trap with floating point. */ | |
2128 if (honor_trapv) | |
2129 return true; | |
2130 return false; | |
2131 | |
2132 case PLUS_EXPR: | |
2133 case MINUS_EXPR: | |
2134 case MULT_EXPR: | |
2135 /* Any floating arithmetic may trap. */ | |
2136 if (fp_operation && flag_trapping_math) | |
2137 return true; | |
2138 if (honor_trapv) | |
2139 return true; | |
2140 return false; | |
2141 | |
2142 default: | |
2143 /* Any floating arithmetic may trap. */ | |
2144 if (fp_operation && flag_trapping_math) | |
2145 return true; | |
2146 | |
2147 *handled = false; | |
2148 return false; | |
2149 } | |
2150 } | |
2151 | |
2152 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied | |
2153 on floating-point values. HONOR_TRAPV is true if OP is applied on integer | |
2154 type operands that may trap. If OP is a division operator, DIVISOR contains | |
2155 the value of the divisor. */ | |
2156 | |
2157 bool | |
2158 operation_could_trap_p (enum tree_code op, bool fp_operation, bool honor_trapv, | |
2159 tree divisor) | |
2160 { | |
2161 bool honor_nans = (fp_operation && flag_trapping_math | |
2162 && !flag_finite_math_only); | |
2163 bool honor_snans = fp_operation && flag_signaling_nans != 0; | |
2164 bool handled; | |
2165 | |
2166 if (TREE_CODE_CLASS (op) != tcc_comparison | |
2167 && TREE_CODE_CLASS (op) != tcc_unary | |
2168 && TREE_CODE_CLASS (op) != tcc_binary) | |
2169 return false; | |
2170 | |
2171 return operation_could_trap_helper_p (op, fp_operation, honor_trapv, | |
2172 honor_nans, honor_snans, divisor, | |
2173 &handled); | |
2174 } | |
2175 | |
2176 /* Return true if EXPR can trap, as in dereferencing an invalid pointer | |
2177 location or floating point arithmetic. C.f. the rtl version, may_trap_p. | |
2178 This routine expects only GIMPLE lhs or rhs input. */ | |
2179 | |
2180 bool | |
2181 tree_could_trap_p (tree expr) | |
2182 { | |
2183 enum tree_code code; | |
2184 bool fp_operation = false; | |
2185 bool honor_trapv = false; | |
2186 tree t, base, div = NULL_TREE; | |
2187 | |
2188 if (!expr) | |
2189 return false; | |
2190 | |
2191 code = TREE_CODE (expr); | |
2192 t = TREE_TYPE (expr); | |
2193 | |
2194 if (t) | |
2195 { | |
2196 if (COMPARISON_CLASS_P (expr)) | |
2197 fp_operation = FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))); | |
2198 else | |
2199 fp_operation = FLOAT_TYPE_P (t); | |
2200 honor_trapv = INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t); | |
2201 } | |
2202 | |
2203 if (TREE_CODE_CLASS (code) == tcc_binary) | |
2204 div = TREE_OPERAND (expr, 1); | |
2205 if (operation_could_trap_p (code, fp_operation, honor_trapv, div)) | |
2206 return true; | |
2207 | |
2208 restart: | |
2209 switch (code) | |
2210 { | |
2211 case TARGET_MEM_REF: | |
2212 /* For TARGET_MEM_REFs use the information based on the original | |
2213 reference. */ | |
2214 expr = TMR_ORIGINAL (expr); | |
2215 code = TREE_CODE (expr); | |
2216 goto restart; | |
2217 | |
2218 case COMPONENT_REF: | |
2219 case REALPART_EXPR: | |
2220 case IMAGPART_EXPR: | |
2221 case BIT_FIELD_REF: | |
2222 case VIEW_CONVERT_EXPR: | |
2223 case WITH_SIZE_EXPR: | |
2224 expr = TREE_OPERAND (expr, 0); | |
2225 code = TREE_CODE (expr); | |
2226 goto restart; | |
2227 | |
2228 case ARRAY_RANGE_REF: | |
2229 base = TREE_OPERAND (expr, 0); | |
2230 if (tree_could_trap_p (base)) | |
2231 return true; | |
2232 | |
2233 if (TREE_THIS_NOTRAP (expr)) | |
2234 return false; | |
2235 | |
2236 return !range_in_array_bounds_p (expr); | |
2237 | |
2238 case ARRAY_REF: | |
2239 base = TREE_OPERAND (expr, 0); | |
2240 if (tree_could_trap_p (base)) | |
2241 return true; | |
2242 | |
2243 if (TREE_THIS_NOTRAP (expr)) | |
2244 return false; | |
2245 | |
2246 return !in_array_bounds_p (expr); | |
2247 | |
2248 case INDIRECT_REF: | |
2249 case ALIGN_INDIRECT_REF: | |
2250 case MISALIGNED_INDIRECT_REF: | |
2251 return !TREE_THIS_NOTRAP (expr); | |
2252 | |
2253 case ASM_EXPR: | |
2254 return TREE_THIS_VOLATILE (expr); | |
2255 | |
2256 | |
2257 case CALL_EXPR: | |
2258 t = get_callee_fndecl (expr); | |
2259 /* Assume that calls to weak functions may trap. */ | |
2260 if (!t || !DECL_P (t) || DECL_WEAK (t)) | |
2261 return true; | |
2262 return false; | |
2263 | |
2264 default: | |
2265 return false; | |
2266 } | |
2267 } | |
2268 | |
2269 | |
2270 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a | |
2271 an assignment or a conditional) may throw. */ | |
2272 | |
2273 static bool | |
2274 stmt_could_throw_1_p (gimple stmt) | |
2275 { | |
2276 enum tree_code code = gimple_expr_code (stmt); | |
2277 bool honor_nans = false; | |
2278 bool honor_snans = false; | |
2279 bool fp_operation = false; | |
2280 bool honor_trapv = false; | |
2281 tree t; | |
2282 size_t i; | |
2283 bool handled, ret; | |
2284 | |
2285 if (TREE_CODE_CLASS (code) == tcc_comparison | |
2286 || TREE_CODE_CLASS (code) == tcc_unary | |
2287 || TREE_CODE_CLASS (code) == tcc_binary) | |
2288 { | |
2289 t = gimple_expr_type (stmt); | |
2290 fp_operation = FLOAT_TYPE_P (t); | |
2291 if (fp_operation) | |
2292 { | |
2293 honor_nans = flag_trapping_math && !flag_finite_math_only; | |
2294 honor_snans = flag_signaling_nans != 0; | |
2295 } | |
2296 else if (INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t)) | |
2297 honor_trapv = true; | |
2298 } | |
2299 | |
2300 /* Check if the main expression may trap. */ | |
2301 t = is_gimple_assign (stmt) ? gimple_assign_rhs2 (stmt) : NULL; | |
2302 ret = operation_could_trap_helper_p (code, fp_operation, honor_trapv, | |
2303 honor_nans, honor_snans, t, | |
2304 &handled); | |
2305 if (handled) | |
2306 return ret; | |
2307 | |
2308 /* If the expression does not trap, see if any of the individual operands may | |
2309 trap. */ | |
2310 for (i = 0; i < gimple_num_ops (stmt); i++) | |
2311 if (tree_could_trap_p (gimple_op (stmt, i))) | |
2312 return true; | |
2313 | |
2314 return false; | |
2315 } | |
2316 | |
2317 | |
2318 /* Return true if statement STMT could throw an exception. */ | |
2319 | |
2320 bool | |
2321 stmt_could_throw_p (gimple stmt) | |
2322 { | |
2323 enum gimple_code code; | |
2324 | |
2325 if (!flag_exceptions) | |
2326 return false; | |
2327 | |
2328 /* The only statements that can throw an exception are assignments, | |
2329 conditionals, calls and asms. */ | |
2330 code = gimple_code (stmt); | |
2331 if (code != GIMPLE_ASSIGN | |
2332 && code != GIMPLE_COND | |
2333 && code != GIMPLE_CALL | |
2334 && code != GIMPLE_ASM) | |
2335 return false; | |
2336 | |
2337 /* If exceptions can only be thrown by function calls and STMT is not a | |
2338 GIMPLE_CALL, the statement cannot throw. */ | |
2339 if (!flag_non_call_exceptions && code != GIMPLE_CALL) | |
2340 return false; | |
2341 | |
2342 if (code == GIMPLE_ASSIGN || code == GIMPLE_COND) | |
2343 return stmt_could_throw_1_p (stmt); | |
2344 else if (is_gimple_call (stmt)) | |
2345 { | |
2346 tree t = gimple_call_fndecl (stmt); | |
2347 | |
2348 /* Assume that calls to weak functions may trap. */ | |
2349 if (!t || !DECL_P (t) || DECL_WEAK (t)) | |
2350 return true; | |
2351 | |
2352 return (gimple_call_flags (stmt) & ECF_NOTHROW) == 0; | |
2353 } | |
2354 else if (gimple_code (stmt) == GIMPLE_ASM) | |
2355 return (gimple_asm_volatile_p (stmt)); | |
2356 else | |
2357 gcc_unreachable (); | |
2358 | |
2359 return false; | |
2360 } | |
2361 | |
2362 | |
2363 /* Return true if expression T could throw an exception. */ | |
2364 | |
2365 bool | |
2366 tree_could_throw_p (tree t) | |
2367 { | |
2368 if (!flag_exceptions) | |
2369 return false; | |
2370 if (TREE_CODE (t) == MODIFY_EXPR) | |
2371 { | |
2372 if (flag_non_call_exceptions | |
2373 && tree_could_trap_p (TREE_OPERAND (t, 0))) | |
2374 return true; | |
2375 t = TREE_OPERAND (t, 1); | |
2376 } | |
2377 | |
2378 if (TREE_CODE (t) == WITH_SIZE_EXPR) | |
2379 t = TREE_OPERAND (t, 0); | |
2380 if (TREE_CODE (t) == CALL_EXPR) | |
2381 return (call_expr_flags (t) & ECF_NOTHROW) == 0; | |
2382 if (flag_non_call_exceptions) | |
2383 return tree_could_trap_p (t); | |
2384 return false; | |
2385 } | |
2386 | |
2387 | |
2388 /* Return true if STMT can throw an exception that is caught within | |
2389 the current function (CFUN). */ | |
2390 | |
2391 bool | |
2392 stmt_can_throw_internal (gimple stmt) | |
2393 { | |
2394 int region_nr; | |
2395 bool is_resx = false; | |
2396 | |
2397 if (gimple_code (stmt) == GIMPLE_RESX) | |
2398 { | |
2399 region_nr = gimple_resx_region (stmt); | |
2400 is_resx = true; | |
2401 } | |
2402 else | |
2403 region_nr = lookup_stmt_eh_region (stmt); | |
2404 | |
2405 if (region_nr < 0) | |
2406 return false; | |
2407 | |
2408 return can_throw_internal_1 (region_nr, is_resx); | |
2409 } | |
2410 | |
2411 | |
2412 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced | |
2413 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT | |
2414 in the table if it should be in there. Return TRUE if a replacement was | |
2415 done that my require an EH edge purge. */ | |
2416 | |
2417 bool | |
2418 maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt) | |
2419 { | |
2420 int region_nr = lookup_stmt_eh_region (old_stmt); | |
2421 | |
2422 if (region_nr >= 0) | |
2423 { | |
2424 bool new_stmt_could_throw = stmt_could_throw_p (new_stmt); | |
2425 | |
2426 if (new_stmt == old_stmt && new_stmt_could_throw) | |
2427 return false; | |
2428 | |
2429 remove_stmt_from_eh_region (old_stmt); | |
2430 if (new_stmt_could_throw) | |
2431 { | |
2432 add_stmt_to_eh_region (new_stmt, region_nr); | |
2433 return false; | |
2434 } | |
2435 else | |
2436 return true; | |
2437 } | |
2438 | |
2439 return false; | |
2440 } | |
2441 | |
2442 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of | |
2443 GIMPLE_TRY) that are similar enough to be considered the same. Currently | |
2444 this only handles handlers consisting of a single call, as that's the | |
2445 important case for C++: a destructor call for a particular object showing | |
2446 up in multiple handlers. */ | |
2447 | |
2448 static bool | |
2449 same_handler_p (gimple_seq oneh, gimple_seq twoh) | |
2450 { | |
2451 gimple_stmt_iterator gsi; | |
2452 gimple ones, twos; | |
2453 unsigned int ai; | |
2454 | |
2455 gsi = gsi_start (oneh); | |
2456 if (!gsi_one_before_end_p (gsi)) | |
2457 return false; | |
2458 ones = gsi_stmt (gsi); | |
2459 | |
2460 gsi = gsi_start (twoh); | |
2461 if (!gsi_one_before_end_p (gsi)) | |
2462 return false; | |
2463 twos = gsi_stmt (gsi); | |
2464 | |
2465 if (!is_gimple_call (ones) | |
2466 || !is_gimple_call (twos) | |
2467 || gimple_call_lhs (ones) | |
2468 || gimple_call_lhs (twos) | |
2469 || gimple_call_chain (ones) | |
2470 || gimple_call_chain (twos) | |
2471 || !operand_equal_p (gimple_call_fn (ones), gimple_call_fn (twos), 0) | |
2472 || gimple_call_num_args (ones) != gimple_call_num_args (twos)) | |
2473 return false; | |
2474 | |
2475 for (ai = 0; ai < gimple_call_num_args (ones); ++ai) | |
2476 if (!operand_equal_p (gimple_call_arg (ones, ai), | |
2477 gimple_call_arg (twos, ai), 0)) | |
2478 return false; | |
2479 | |
2480 return true; | |
2481 } | |
2482 | |
2483 /* Optimize | |
2484 try { A() } finally { try { ~B() } catch { ~A() } } | |
2485 try { ... } finally { ~A() } | |
2486 into | |
2487 try { A() } catch { ~B() } | |
2488 try { ~B() ... } finally { ~A() } | |
2489 | |
2490 This occurs frequently in C++, where A is a local variable and B is a | |
2491 temporary used in the initializer for A. */ | |
2492 | |
2493 static void | |
2494 optimize_double_finally (gimple one, gimple two) | |
2495 { | |
2496 gimple oneh; | |
2497 gimple_stmt_iterator gsi; | |
2498 | |
2499 gsi = gsi_start (gimple_try_cleanup (one)); | |
2500 if (!gsi_one_before_end_p (gsi)) | |
2501 return; | |
2502 | |
2503 oneh = gsi_stmt (gsi); | |
2504 if (gimple_code (oneh) != GIMPLE_TRY | |
2505 || gimple_try_kind (oneh) != GIMPLE_TRY_CATCH) | |
2506 return; | |
2507 | |
2508 if (same_handler_p (gimple_try_cleanup (oneh), gimple_try_cleanup (two))) | |
2509 { | |
2510 gimple_seq seq = gimple_try_eval (oneh); | |
2511 | |
2512 gimple_try_set_cleanup (one, seq); | |
2513 gimple_try_set_kind (one, GIMPLE_TRY_CATCH); | |
2514 seq = copy_gimple_seq_and_replace_locals (seq); | |
2515 gimple_seq_add_seq (&seq, gimple_try_eval (two)); | |
2516 gimple_try_set_eval (two, seq); | |
2517 } | |
2518 } | |
2519 | |
2520 /* Perform EH refactoring optimizations that are simpler to do when code | |
2521 flow has been lowered but EH structures haven't. */ | |
2522 | |
2523 static void | |
2524 refactor_eh_r (gimple_seq seq) | |
2525 { | |
2526 gimple_stmt_iterator gsi; | |
2527 gimple one, two; | |
2528 | |
2529 one = NULL; | |
2530 two = NULL; | |
2531 gsi = gsi_start (seq); | |
2532 while (1) | |
2533 { | |
2534 one = two; | |
2535 if (gsi_end_p (gsi)) | |
2536 two = NULL; | |
2537 else | |
2538 two = gsi_stmt (gsi); | |
2539 if (one | |
2540 && two | |
2541 && gimple_code (one) == GIMPLE_TRY | |
2542 && gimple_code (two) == GIMPLE_TRY | |
2543 && gimple_try_kind (one) == GIMPLE_TRY_FINALLY | |
2544 && gimple_try_kind (two) == GIMPLE_TRY_FINALLY) | |
2545 optimize_double_finally (one, two); | |
2546 if (one) | |
2547 switch (gimple_code (one)) | |
2548 { | |
2549 case GIMPLE_TRY: | |
2550 refactor_eh_r (gimple_try_eval (one)); | |
2551 refactor_eh_r (gimple_try_cleanup (one)); | |
2552 break; | |
2553 case GIMPLE_CATCH: | |
2554 refactor_eh_r (gimple_catch_handler (one)); | |
2555 break; | |
2556 case GIMPLE_EH_FILTER: | |
2557 refactor_eh_r (gimple_eh_filter_failure (one)); | |
2558 break; | |
2559 default: | |
2560 break; | |
2561 } | |
2562 if (two) | |
2563 gsi_next (&gsi); | |
2564 else | |
2565 break; | |
2566 } | |
2567 } | |
2568 | |
2569 static unsigned | |
2570 refactor_eh (void) | |
2571 { | |
2572 refactor_eh_r (gimple_body (current_function_decl)); | |
2573 return 0; | |
2574 } | |
2575 | |
2576 struct gimple_opt_pass pass_refactor_eh = | |
2577 { | |
2578 { | |
2579 GIMPLE_PASS, | |
2580 "ehopt", /* name */ | |
2581 NULL, /* gate */ | |
2582 refactor_eh, /* execute */ | |
2583 NULL, /* sub */ | |
2584 NULL, /* next */ | |
2585 0, /* static_pass_number */ | |
2586 TV_TREE_EH, /* tv_id */ | |
2587 PROP_gimple_lcf, /* properties_required */ | |
2588 0, /* properties_provided */ | |
2589 0, /* properties_destroyed */ | |
2590 0, /* todo_flags_start */ | |
2591 TODO_dump_func /* todo_flags_finish */ | |
2592 } | |
2593 }; |