Daily bump.
[official-gcc.git] / gcc / tree-eh.c
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1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
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 3, or (at your option)
9 any later version.
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.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "hash-table.h"
24 #include "tm.h"
25 #include "tree.h"
26 #include "expr.h"
27 #include "calls.h"
28 #include "flags.h"
29 #include "function.h"
30 #include "except.h"
31 #include "pointer-set.h"
32 #include "basic-block.h"
33 #include "tree-ssa-alias.h"
34 #include "internal-fn.h"
35 #include "tree-eh.h"
36 #include "gimple-expr.h"
37 #include "is-a.h"
38 #include "gimple.h"
39 #include "gimple-iterator.h"
40 #include "gimple-ssa.h"
41 #include "cgraph.h"
42 #include "tree-cfg.h"
43 #include "tree-phinodes.h"
44 #include "ssa-iterators.h"
45 #include "stringpool.h"
46 #include "tree-ssanames.h"
47 #include "tree-into-ssa.h"
48 #include "tree-ssa.h"
49 #include "tree-inline.h"
50 #include "tree-pass.h"
51 #include "langhooks.h"
52 #include "diagnostic-core.h"
53 #include "target.h"
54 #include "cfgloop.h"
55 #include "gimple-low.h"
57 /* In some instances a tree and a gimple need to be stored in a same table,
58 i.e. in hash tables. This is a structure to do this. */
59 typedef union {tree *tp; tree t; gimple g;} treemple;
61 /* Misc functions used in this file. */
63 /* Remember and lookup EH landing pad data for arbitrary statements.
64 Really this means any statement that could_throw_p. We could
65 stuff this information into the stmt_ann data structure, but:
67 (1) We absolutely rely on this information being kept until
68 we get to rtl. Once we're done with lowering here, if we lose
69 the information there's no way to recover it!
71 (2) There are many more statements that *cannot* throw as
72 compared to those that can. We should be saving some amount
73 of space by only allocating memory for those that can throw. */
75 /* Add statement T in function IFUN to landing pad NUM. */
77 static void
78 add_stmt_to_eh_lp_fn (struct function *ifun, gimple t, int num)
80 struct throw_stmt_node *n;
81 void **slot;
83 gcc_assert (num != 0);
85 n = ggc_alloc_throw_stmt_node ();
86 n->stmt = t;
87 n->lp_nr = num;
89 if (!get_eh_throw_stmt_table (ifun))
90 set_eh_throw_stmt_table (ifun, htab_create_ggc (31, struct_ptr_hash,
91 struct_ptr_eq,
92 ggc_free));
94 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), n, INSERT);
95 gcc_assert (!*slot);
96 *slot = n;
99 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
101 void
102 add_stmt_to_eh_lp (gimple t, int num)
104 add_stmt_to_eh_lp_fn (cfun, t, num);
107 /* Add statement T to the single EH landing pad in REGION. */
109 static void
110 record_stmt_eh_region (eh_region region, gimple t)
112 if (region == NULL)
113 return;
114 if (region->type == ERT_MUST_NOT_THROW)
115 add_stmt_to_eh_lp_fn (cfun, t, -region->index);
116 else
118 eh_landing_pad lp = region->landing_pads;
119 if (lp == NULL)
120 lp = gen_eh_landing_pad (region);
121 else
122 gcc_assert (lp->next_lp == NULL);
123 add_stmt_to_eh_lp_fn (cfun, t, lp->index);
128 /* Remove statement T in function IFUN from its EH landing pad. */
130 bool
131 remove_stmt_from_eh_lp_fn (struct function *ifun, gimple t)
133 struct throw_stmt_node dummy;
134 void **slot;
136 if (!get_eh_throw_stmt_table (ifun))
137 return false;
139 dummy.stmt = t;
140 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), &dummy,
141 NO_INSERT);
142 if (slot)
144 htab_clear_slot (get_eh_throw_stmt_table (ifun), slot);
145 return true;
147 else
148 return false;
152 /* Remove statement T in the current function (cfun) from its
153 EH landing pad. */
155 bool
156 remove_stmt_from_eh_lp (gimple t)
158 return remove_stmt_from_eh_lp_fn (cfun, t);
161 /* Determine if statement T is inside an EH region in function IFUN.
162 Positive numbers indicate a landing pad index; negative numbers
163 indicate a MUST_NOT_THROW region index; zero indicates that the
164 statement is not recorded in the region table. */
167 lookup_stmt_eh_lp_fn (struct function *ifun, gimple t)
169 struct throw_stmt_node *p, n;
171 if (ifun->eh->throw_stmt_table == NULL)
172 return 0;
174 n.stmt = t;
175 p = (struct throw_stmt_node *) htab_find (ifun->eh->throw_stmt_table, &n);
176 return p ? p->lp_nr : 0;
179 /* Likewise, but always use the current function. */
182 lookup_stmt_eh_lp (gimple t)
184 /* We can get called from initialized data when -fnon-call-exceptions
185 is on; prevent crash. */
186 if (!cfun)
187 return 0;
188 return lookup_stmt_eh_lp_fn (cfun, t);
191 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
192 nodes and LABEL_DECL nodes. We will use this during the second phase to
193 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
195 struct finally_tree_node
197 /* When storing a GIMPLE_TRY, we have to record a gimple. However
198 when deciding whether a GOTO to a certain LABEL_DECL (which is a
199 tree) leaves the TRY block, its necessary to record a tree in
200 this field. Thus a treemple is used. */
201 treemple child;
202 gimple parent;
205 /* Hashtable helpers. */
207 struct finally_tree_hasher : typed_free_remove <finally_tree_node>
209 typedef finally_tree_node value_type;
210 typedef finally_tree_node compare_type;
211 static inline hashval_t hash (const value_type *);
212 static inline bool equal (const value_type *, const compare_type *);
215 inline hashval_t
216 finally_tree_hasher::hash (const value_type *v)
218 return (intptr_t)v->child.t >> 4;
221 inline bool
222 finally_tree_hasher::equal (const value_type *v, const compare_type *c)
224 return v->child.t == c->child.t;
227 /* Note that this table is *not* marked GTY. It is short-lived. */
228 static hash_table <finally_tree_hasher> finally_tree;
230 static void
231 record_in_finally_tree (treemple child, gimple parent)
233 struct finally_tree_node *n;
234 finally_tree_node **slot;
236 n = XNEW (struct finally_tree_node);
237 n->child = child;
238 n->parent = parent;
240 slot = finally_tree.find_slot (n, INSERT);
241 gcc_assert (!*slot);
242 *slot = n;
245 static void
246 collect_finally_tree (gimple stmt, gimple region);
248 /* Go through the gimple sequence. Works with collect_finally_tree to
249 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
251 static void
252 collect_finally_tree_1 (gimple_seq seq, gimple region)
254 gimple_stmt_iterator gsi;
256 for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi))
257 collect_finally_tree (gsi_stmt (gsi), region);
260 static void
261 collect_finally_tree (gimple stmt, gimple region)
263 treemple temp;
265 switch (gimple_code (stmt))
267 case GIMPLE_LABEL:
268 temp.t = gimple_label_label (stmt);
269 record_in_finally_tree (temp, region);
270 break;
272 case GIMPLE_TRY:
273 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
275 temp.g = stmt;
276 record_in_finally_tree (temp, region);
277 collect_finally_tree_1 (gimple_try_eval (stmt), stmt);
278 collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
280 else if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH)
282 collect_finally_tree_1 (gimple_try_eval (stmt), region);
283 collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
285 break;
287 case GIMPLE_CATCH:
288 collect_finally_tree_1 (gimple_catch_handler (stmt), region);
289 break;
291 case GIMPLE_EH_FILTER:
292 collect_finally_tree_1 (gimple_eh_filter_failure (stmt), region);
293 break;
295 case GIMPLE_EH_ELSE:
296 collect_finally_tree_1 (gimple_eh_else_n_body (stmt), region);
297 collect_finally_tree_1 (gimple_eh_else_e_body (stmt), region);
298 break;
300 default:
301 /* A type, a decl, or some kind of statement that we're not
302 interested in. Don't walk them. */
303 break;
308 /* Use the finally tree to determine if a jump from START to TARGET
309 would leave the try_finally node that START lives in. */
311 static bool
312 outside_finally_tree (treemple start, gimple target)
314 struct finally_tree_node n, *p;
318 n.child = start;
319 p = finally_tree.find (&n);
320 if (!p)
321 return true;
322 start.g = p->parent;
324 while (start.g != target);
326 return false;
329 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
330 nodes into a set of gotos, magic labels, and eh regions.
331 The eh region creation is straight-forward, but frobbing all the gotos
332 and such into shape isn't. */
334 /* The sequence into which we record all EH stuff. This will be
335 placed at the end of the function when we're all done. */
336 static gimple_seq eh_seq;
338 /* Record whether an EH region contains something that can throw,
339 indexed by EH region number. */
340 static bitmap eh_region_may_contain_throw_map;
342 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
343 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
344 The idea is to record a gimple statement for everything except for
345 the conditionals, which get their labels recorded. Since labels are
346 of type 'tree', we need this node to store both gimple and tree
347 objects. REPL_STMT is the sequence used to replace the goto/return
348 statement. CONT_STMT is used to store the statement that allows
349 the return/goto to jump to the original destination. */
351 struct goto_queue_node
353 treemple stmt;
354 location_t location;
355 gimple_seq repl_stmt;
356 gimple cont_stmt;
357 int index;
358 /* This is used when index >= 0 to indicate that stmt is a label (as
359 opposed to a goto stmt). */
360 int is_label;
363 /* State of the world while lowering. */
365 struct leh_state
367 /* What's "current" while constructing the eh region tree. These
368 correspond to variables of the same name in cfun->eh, which we
369 don't have easy access to. */
370 eh_region cur_region;
372 /* What's "current" for the purposes of __builtin_eh_pointer. For
373 a CATCH, this is the associated TRY. For an EH_FILTER, this is
374 the associated ALLOWED_EXCEPTIONS, etc. */
375 eh_region ehp_region;
377 /* Processing of TRY_FINALLY requires a bit more state. This is
378 split out into a separate structure so that we don't have to
379 copy so much when processing other nodes. */
380 struct leh_tf_state *tf;
383 struct leh_tf_state
385 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
386 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
387 this so that outside_finally_tree can reliably reference the tree used
388 in the collect_finally_tree data structures. */
389 gimple try_finally_expr;
390 gimple top_p;
392 /* While lowering a top_p usually it is expanded into multiple statements,
393 thus we need the following field to store them. */
394 gimple_seq top_p_seq;
396 /* The state outside this try_finally node. */
397 struct leh_state *outer;
399 /* The exception region created for it. */
400 eh_region region;
402 /* The goto queue. */
403 struct goto_queue_node *goto_queue;
404 size_t goto_queue_size;
405 size_t goto_queue_active;
407 /* Pointer map to help in searching goto_queue when it is large. */
408 struct pointer_map_t *goto_queue_map;
410 /* The set of unique labels seen as entries in the goto queue. */
411 vec<tree> dest_array;
413 /* A label to be added at the end of the completed transformed
414 sequence. It will be set if may_fallthru was true *at one time*,
415 though subsequent transformations may have cleared that flag. */
416 tree fallthru_label;
418 /* True if it is possible to fall out the bottom of the try block.
419 Cleared if the fallthru is converted to a goto. */
420 bool may_fallthru;
422 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
423 bool may_return;
425 /* True if the finally block can receive an exception edge.
426 Cleared if the exception case is handled by code duplication. */
427 bool may_throw;
430 static gimple_seq lower_eh_must_not_throw (struct leh_state *, gimple);
432 /* Search for STMT in the goto queue. Return the replacement,
433 or null if the statement isn't in the queue. */
435 #define LARGE_GOTO_QUEUE 20
437 static void lower_eh_constructs_1 (struct leh_state *state, gimple_seq *seq);
439 static gimple_seq
440 find_goto_replacement (struct leh_tf_state *tf, treemple stmt)
442 unsigned int i;
443 void **slot;
445 if (tf->goto_queue_active < LARGE_GOTO_QUEUE)
447 for (i = 0; i < tf->goto_queue_active; i++)
448 if ( tf->goto_queue[i].stmt.g == stmt.g)
449 return tf->goto_queue[i].repl_stmt;
450 return NULL;
453 /* If we have a large number of entries in the goto_queue, create a
454 pointer map and use that for searching. */
456 if (!tf->goto_queue_map)
458 tf->goto_queue_map = pointer_map_create ();
459 for (i = 0; i < tf->goto_queue_active; i++)
461 slot = pointer_map_insert (tf->goto_queue_map,
462 tf->goto_queue[i].stmt.g);
463 gcc_assert (*slot == NULL);
464 *slot = &tf->goto_queue[i];
468 slot = pointer_map_contains (tf->goto_queue_map, stmt.g);
469 if (slot != NULL)
470 return (((struct goto_queue_node *) *slot)->repl_stmt);
472 return NULL;
475 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
476 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
477 then we can just splat it in, otherwise we add the new stmts immediately
478 after the GIMPLE_COND and redirect. */
480 static void
481 replace_goto_queue_cond_clause (tree *tp, struct leh_tf_state *tf,
482 gimple_stmt_iterator *gsi)
484 tree label;
485 gimple_seq new_seq;
486 treemple temp;
487 location_t loc = gimple_location (gsi_stmt (*gsi));
489 temp.tp = tp;
490 new_seq = find_goto_replacement (tf, temp);
491 if (!new_seq)
492 return;
494 if (gimple_seq_singleton_p (new_seq)
495 && gimple_code (gimple_seq_first_stmt (new_seq)) == GIMPLE_GOTO)
497 *tp = gimple_goto_dest (gimple_seq_first_stmt (new_seq));
498 return;
501 label = create_artificial_label (loc);
502 /* Set the new label for the GIMPLE_COND */
503 *tp = label;
505 gsi_insert_after (gsi, gimple_build_label (label), GSI_CONTINUE_LINKING);
506 gsi_insert_seq_after (gsi, gimple_seq_copy (new_seq), GSI_CONTINUE_LINKING);
509 /* The real work of replace_goto_queue. Returns with TSI updated to
510 point to the next statement. */
512 static void replace_goto_queue_stmt_list (gimple_seq *, struct leh_tf_state *);
514 static void
515 replace_goto_queue_1 (gimple stmt, struct leh_tf_state *tf,
516 gimple_stmt_iterator *gsi)
518 gimple_seq seq;
519 treemple temp;
520 temp.g = NULL;
522 switch (gimple_code (stmt))
524 case GIMPLE_GOTO:
525 case GIMPLE_RETURN:
526 temp.g = stmt;
527 seq = find_goto_replacement (tf, temp);
528 if (seq)
530 gsi_insert_seq_before (gsi, gimple_seq_copy (seq), GSI_SAME_STMT);
531 gsi_remove (gsi, false);
532 return;
534 break;
536 case GIMPLE_COND:
537 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 2), tf, gsi);
538 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 3), tf, gsi);
539 break;
541 case GIMPLE_TRY:
542 replace_goto_queue_stmt_list (gimple_try_eval_ptr (stmt), tf);
543 replace_goto_queue_stmt_list (gimple_try_cleanup_ptr (stmt), tf);
544 break;
545 case GIMPLE_CATCH:
546 replace_goto_queue_stmt_list (gimple_catch_handler_ptr (stmt), tf);
547 break;
548 case GIMPLE_EH_FILTER:
549 replace_goto_queue_stmt_list (gimple_eh_filter_failure_ptr (stmt), tf);
550 break;
551 case GIMPLE_EH_ELSE:
552 replace_goto_queue_stmt_list (gimple_eh_else_n_body_ptr (stmt), tf);
553 replace_goto_queue_stmt_list (gimple_eh_else_e_body_ptr (stmt), tf);
554 break;
556 default:
557 /* These won't have gotos in them. */
558 break;
561 gsi_next (gsi);
564 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
566 static void
567 replace_goto_queue_stmt_list (gimple_seq *seq, struct leh_tf_state *tf)
569 gimple_stmt_iterator gsi = gsi_start (*seq);
571 while (!gsi_end_p (gsi))
572 replace_goto_queue_1 (gsi_stmt (gsi), tf, &gsi);
575 /* Replace all goto queue members. */
577 static void
578 replace_goto_queue (struct leh_tf_state *tf)
580 if (tf->goto_queue_active == 0)
581 return;
582 replace_goto_queue_stmt_list (&tf->top_p_seq, tf);
583 replace_goto_queue_stmt_list (&eh_seq, tf);
586 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
587 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
588 a gimple return. */
590 static void
591 record_in_goto_queue (struct leh_tf_state *tf,
592 treemple new_stmt,
593 int index,
594 bool is_label,
595 location_t location)
597 size_t active, size;
598 struct goto_queue_node *q;
600 gcc_assert (!tf->goto_queue_map);
602 active = tf->goto_queue_active;
603 size = tf->goto_queue_size;
604 if (active >= size)
606 size = (size ? size * 2 : 32);
607 tf->goto_queue_size = size;
608 tf->goto_queue
609 = XRESIZEVEC (struct goto_queue_node, tf->goto_queue, size);
612 q = &tf->goto_queue[active];
613 tf->goto_queue_active = active + 1;
615 memset (q, 0, sizeof (*q));
616 q->stmt = new_stmt;
617 q->index = index;
618 q->location = location;
619 q->is_label = is_label;
622 /* Record the LABEL label in the goto queue contained in TF.
623 TF is not null. */
625 static void
626 record_in_goto_queue_label (struct leh_tf_state *tf, treemple stmt, tree label,
627 location_t location)
629 int index;
630 treemple temp, new_stmt;
632 if (!label)
633 return;
635 /* Computed and non-local gotos do not get processed. Given
636 their nature we can neither tell whether we've escaped the
637 finally block nor redirect them if we knew. */
638 if (TREE_CODE (label) != LABEL_DECL)
639 return;
641 /* No need to record gotos that don't leave the try block. */
642 temp.t = label;
643 if (!outside_finally_tree (temp, tf->try_finally_expr))
644 return;
646 if (! tf->dest_array.exists ())
648 tf->dest_array.create (10);
649 tf->dest_array.quick_push (label);
650 index = 0;
652 else
654 int n = tf->dest_array.length ();
655 for (index = 0; index < n; ++index)
656 if (tf->dest_array[index] == label)
657 break;
658 if (index == n)
659 tf->dest_array.safe_push (label);
662 /* In the case of a GOTO we want to record the destination label,
663 since with a GIMPLE_COND we have an easy access to the then/else
664 labels. */
665 new_stmt = stmt;
666 record_in_goto_queue (tf, new_stmt, index, true, location);
669 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
670 node, and if so record that fact in the goto queue associated with that
671 try_finally node. */
673 static void
674 maybe_record_in_goto_queue (struct leh_state *state, gimple stmt)
676 struct leh_tf_state *tf = state->tf;
677 treemple new_stmt;
679 if (!tf)
680 return;
682 switch (gimple_code (stmt))
684 case GIMPLE_COND:
685 new_stmt.tp = gimple_op_ptr (stmt, 2);
686 record_in_goto_queue_label (tf, new_stmt, gimple_cond_true_label (stmt),
687 EXPR_LOCATION (*new_stmt.tp));
688 new_stmt.tp = gimple_op_ptr (stmt, 3);
689 record_in_goto_queue_label (tf, new_stmt, gimple_cond_false_label (stmt),
690 EXPR_LOCATION (*new_stmt.tp));
691 break;
692 case GIMPLE_GOTO:
693 new_stmt.g = stmt;
694 record_in_goto_queue_label (tf, new_stmt, gimple_goto_dest (stmt),
695 gimple_location (stmt));
696 break;
698 case GIMPLE_RETURN:
699 tf->may_return = true;
700 new_stmt.g = stmt;
701 record_in_goto_queue (tf, new_stmt, -1, false, gimple_location (stmt));
702 break;
704 default:
705 gcc_unreachable ();
710 #ifdef ENABLE_CHECKING
711 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
712 was in fact structured, and we've not yet done jump threading, then none
713 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
715 static void
716 verify_norecord_switch_expr (struct leh_state *state, gimple switch_expr)
718 struct leh_tf_state *tf = state->tf;
719 size_t i, n;
721 if (!tf)
722 return;
724 n = gimple_switch_num_labels (switch_expr);
726 for (i = 0; i < n; ++i)
728 treemple temp;
729 tree lab = CASE_LABEL (gimple_switch_label (switch_expr, i));
730 temp.t = lab;
731 gcc_assert (!outside_finally_tree (temp, tf->try_finally_expr));
734 #else
735 #define verify_norecord_switch_expr(state, switch_expr)
736 #endif
738 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
739 non-null, insert it before the new branch. */
741 static void
742 do_return_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod)
744 gimple x;
746 /* In the case of a return, the queue node must be a gimple statement. */
747 gcc_assert (!q->is_label);
749 /* Note that the return value may have already been computed, e.g.,
751 int x;
752 int foo (void)
754 x = 0;
755 try {
756 return x;
757 } finally {
758 x++;
762 should return 0, not 1. We don't have to do anything to make
763 this happens because the return value has been placed in the
764 RESULT_DECL already. */
766 q->cont_stmt = q->stmt.g;
768 if (mod)
769 gimple_seq_add_seq (&q->repl_stmt, mod);
771 x = gimple_build_goto (finlab);
772 gimple_set_location (x, q->location);
773 gimple_seq_add_stmt (&q->repl_stmt, x);
776 /* Similar, but easier, for GIMPLE_GOTO. */
778 static void
779 do_goto_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod,
780 struct leh_tf_state *tf)
782 gimple x;
784 gcc_assert (q->is_label);
786 q->cont_stmt = gimple_build_goto (tf->dest_array[q->index]);
788 if (mod)
789 gimple_seq_add_seq (&q->repl_stmt, mod);
791 x = gimple_build_goto (finlab);
792 gimple_set_location (x, q->location);
793 gimple_seq_add_stmt (&q->repl_stmt, x);
796 /* Emit a standard landing pad sequence into SEQ for REGION. */
798 static void
799 emit_post_landing_pad (gimple_seq *seq, eh_region region)
801 eh_landing_pad lp = region->landing_pads;
802 gimple x;
804 if (lp == NULL)
805 lp = gen_eh_landing_pad (region);
807 lp->post_landing_pad = create_artificial_label (UNKNOWN_LOCATION);
808 EH_LANDING_PAD_NR (lp->post_landing_pad) = lp->index;
810 x = gimple_build_label (lp->post_landing_pad);
811 gimple_seq_add_stmt (seq, x);
814 /* Emit a RESX statement into SEQ for REGION. */
816 static void
817 emit_resx (gimple_seq *seq, eh_region region)
819 gimple x = gimple_build_resx (region->index);
820 gimple_seq_add_stmt (seq, x);
821 if (region->outer)
822 record_stmt_eh_region (region->outer, x);
825 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
827 static void
828 emit_eh_dispatch (gimple_seq *seq, eh_region region)
830 gimple x = gimple_build_eh_dispatch (region->index);
831 gimple_seq_add_stmt (seq, x);
834 /* Note that the current EH region may contain a throw, or a
835 call to a function which itself may contain a throw. */
837 static void
838 note_eh_region_may_contain_throw (eh_region region)
840 while (bitmap_set_bit (eh_region_may_contain_throw_map, region->index))
842 if (region->type == ERT_MUST_NOT_THROW)
843 break;
844 region = region->outer;
845 if (region == NULL)
846 break;
850 /* Check if REGION has been marked as containing a throw. If REGION is
851 NULL, this predicate is false. */
853 static inline bool
854 eh_region_may_contain_throw (eh_region r)
856 return r && bitmap_bit_p (eh_region_may_contain_throw_map, r->index);
859 /* We want to transform
860 try { body; } catch { stuff; }
862 normal_seqence:
863 body;
864 over:
865 eh_seqence:
866 landing_pad:
867 stuff;
868 goto over;
870 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
871 should be placed before the second operand, or NULL. OVER is
872 an existing label that should be put at the exit, or NULL. */
874 static gimple_seq
875 frob_into_branch_around (gimple tp, eh_region region, tree over)
877 gimple x;
878 gimple_seq cleanup, result;
879 location_t loc = gimple_location (tp);
881 cleanup = gimple_try_cleanup (tp);
882 result = gimple_try_eval (tp);
884 if (region)
885 emit_post_landing_pad (&eh_seq, region);
887 if (gimple_seq_may_fallthru (cleanup))
889 if (!over)
890 over = create_artificial_label (loc);
891 x = gimple_build_goto (over);
892 gimple_set_location (x, loc);
893 gimple_seq_add_stmt (&cleanup, x);
895 gimple_seq_add_seq (&eh_seq, cleanup);
897 if (over)
899 x = gimple_build_label (over);
900 gimple_seq_add_stmt (&result, x);
902 return result;
905 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
906 Make sure to record all new labels found. */
908 static gimple_seq
909 lower_try_finally_dup_block (gimple_seq seq, struct leh_state *outer_state,
910 location_t loc)
912 gimple region = NULL;
913 gimple_seq new_seq;
914 gimple_stmt_iterator gsi;
916 new_seq = copy_gimple_seq_and_replace_locals (seq);
918 for (gsi = gsi_start (new_seq); !gsi_end_p (gsi); gsi_next (&gsi))
920 gimple stmt = gsi_stmt (gsi);
921 if (LOCATION_LOCUS (gimple_location (stmt)) == UNKNOWN_LOCATION)
923 tree block = gimple_block (stmt);
924 gimple_set_location (stmt, loc);
925 gimple_set_block (stmt, block);
929 if (outer_state->tf)
930 region = outer_state->tf->try_finally_expr;
931 collect_finally_tree_1 (new_seq, region);
933 return new_seq;
936 /* A subroutine of lower_try_finally. Create a fallthru label for
937 the given try_finally state. The only tricky bit here is that
938 we have to make sure to record the label in our outer context. */
940 static tree
941 lower_try_finally_fallthru_label (struct leh_tf_state *tf)
943 tree label = tf->fallthru_label;
944 treemple temp;
946 if (!label)
948 label = create_artificial_label (gimple_location (tf->try_finally_expr));
949 tf->fallthru_label = label;
950 if (tf->outer->tf)
952 temp.t = label;
953 record_in_finally_tree (temp, tf->outer->tf->try_finally_expr);
956 return label;
959 /* A subroutine of lower_try_finally. If FINALLY consits of a
960 GIMPLE_EH_ELSE node, return it. */
962 static inline gimple
963 get_eh_else (gimple_seq finally)
965 gimple x = gimple_seq_first_stmt (finally);
966 if (gimple_code (x) == GIMPLE_EH_ELSE)
968 gcc_assert (gimple_seq_singleton_p (finally));
969 return x;
971 return NULL;
974 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
975 langhook returns non-null, then the language requires that the exception
976 path out of a try_finally be treated specially. To wit: the code within
977 the finally block may not itself throw an exception. We have two choices
978 here. First we can duplicate the finally block and wrap it in a
979 must_not_throw region. Second, we can generate code like
981 try {
982 finally_block;
983 } catch {
984 if (fintmp == eh_edge)
985 protect_cleanup_actions;
988 where "fintmp" is the temporary used in the switch statement generation
989 alternative considered below. For the nonce, we always choose the first
990 option.
992 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
994 static void
995 honor_protect_cleanup_actions (struct leh_state *outer_state,
996 struct leh_state *this_state,
997 struct leh_tf_state *tf)
999 tree protect_cleanup_actions;
1000 gimple_stmt_iterator gsi;
1001 bool finally_may_fallthru;
1002 gimple_seq finally;
1003 gimple x, eh_else;
1005 /* First check for nothing to do. */
1006 if (lang_hooks.eh_protect_cleanup_actions == NULL)
1007 return;
1008 protect_cleanup_actions = lang_hooks.eh_protect_cleanup_actions ();
1009 if (protect_cleanup_actions == NULL)
1010 return;
1012 finally = gimple_try_cleanup (tf->top_p);
1013 eh_else = get_eh_else (finally);
1015 /* Duplicate the FINALLY block. Only need to do this for try-finally,
1016 and not for cleanups. If we've got an EH_ELSE, extract it now. */
1017 if (eh_else)
1019 finally = gimple_eh_else_e_body (eh_else);
1020 gimple_try_set_cleanup (tf->top_p, gimple_eh_else_n_body (eh_else));
1022 else if (this_state)
1023 finally = lower_try_finally_dup_block (finally, outer_state,
1024 gimple_location (tf->try_finally_expr));
1025 finally_may_fallthru = gimple_seq_may_fallthru (finally);
1027 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1028 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1029 to be in an enclosing scope, but needs to be implemented at this level
1030 to avoid a nesting violation (see wrap_temporary_cleanups in
1031 cp/decl.c). Since it's logically at an outer level, we should call
1032 terminate before we get to it, so strip it away before adding the
1033 MUST_NOT_THROW filter. */
1034 gsi = gsi_start (finally);
1035 x = gsi_stmt (gsi);
1036 if (gimple_code (x) == GIMPLE_TRY
1037 && gimple_try_kind (x) == GIMPLE_TRY_CATCH
1038 && gimple_try_catch_is_cleanup (x))
1040 gsi_insert_seq_before (&gsi, gimple_try_eval (x), GSI_SAME_STMT);
1041 gsi_remove (&gsi, false);
1044 /* Wrap the block with protect_cleanup_actions as the action. */
1045 x = gimple_build_eh_must_not_throw (protect_cleanup_actions);
1046 x = gimple_build_try (finally, gimple_seq_alloc_with_stmt (x),
1047 GIMPLE_TRY_CATCH);
1048 finally = lower_eh_must_not_throw (outer_state, x);
1050 /* Drop all of this into the exception sequence. */
1051 emit_post_landing_pad (&eh_seq, tf->region);
1052 gimple_seq_add_seq (&eh_seq, finally);
1053 if (finally_may_fallthru)
1054 emit_resx (&eh_seq, tf->region);
1056 /* Having now been handled, EH isn't to be considered with
1057 the rest of the outgoing edges. */
1058 tf->may_throw = false;
1061 /* A subroutine of lower_try_finally. We have determined that there is
1062 no fallthru edge out of the finally block. This means that there is
1063 no outgoing edge corresponding to any incoming edge. Restructure the
1064 try_finally node for this special case. */
1066 static void
1067 lower_try_finally_nofallthru (struct leh_state *state,
1068 struct leh_tf_state *tf)
1070 tree lab;
1071 gimple x, eh_else;
1072 gimple_seq finally;
1073 struct goto_queue_node *q, *qe;
1075 lab = create_artificial_label (gimple_location (tf->try_finally_expr));
1077 /* We expect that tf->top_p is a GIMPLE_TRY. */
1078 finally = gimple_try_cleanup (tf->top_p);
1079 tf->top_p_seq = gimple_try_eval (tf->top_p);
1081 x = gimple_build_label (lab);
1082 gimple_seq_add_stmt (&tf->top_p_seq, x);
1084 q = tf->goto_queue;
1085 qe = q + tf->goto_queue_active;
1086 for (; q < qe; ++q)
1087 if (q->index < 0)
1088 do_return_redirection (q, lab, NULL);
1089 else
1090 do_goto_redirection (q, lab, NULL, tf);
1092 replace_goto_queue (tf);
1094 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1095 eh_else = get_eh_else (finally);
1096 if (eh_else)
1098 finally = gimple_eh_else_n_body (eh_else);
1099 lower_eh_constructs_1 (state, &finally);
1100 gimple_seq_add_seq (&tf->top_p_seq, finally);
1102 if (tf->may_throw)
1104 finally = gimple_eh_else_e_body (eh_else);
1105 lower_eh_constructs_1 (state, &finally);
1107 emit_post_landing_pad (&eh_seq, tf->region);
1108 gimple_seq_add_seq (&eh_seq, finally);
1111 else
1113 lower_eh_constructs_1 (state, &finally);
1114 gimple_seq_add_seq (&tf->top_p_seq, finally);
1116 if (tf->may_throw)
1118 emit_post_landing_pad (&eh_seq, tf->region);
1120 x = gimple_build_goto (lab);
1121 gimple_set_location (x, gimple_location (tf->try_finally_expr));
1122 gimple_seq_add_stmt (&eh_seq, x);
1127 /* A subroutine of lower_try_finally. We have determined that there is
1128 exactly one destination of the finally block. Restructure the
1129 try_finally node for this special case. */
1131 static void
1132 lower_try_finally_onedest (struct leh_state *state, struct leh_tf_state *tf)
1134 struct goto_queue_node *q, *qe;
1135 gimple x;
1136 gimple_seq finally;
1137 gimple_stmt_iterator gsi;
1138 tree finally_label;
1139 location_t loc = gimple_location (tf->try_finally_expr);
1141 finally = gimple_try_cleanup (tf->top_p);
1142 tf->top_p_seq = gimple_try_eval (tf->top_p);
1144 /* Since there's only one destination, and the destination edge can only
1145 either be EH or non-EH, that implies that all of our incoming edges
1146 are of the same type. Therefore we can lower EH_ELSE immediately. */
1147 x = get_eh_else (finally);
1148 if (x)
1150 if (tf->may_throw)
1151 finally = gimple_eh_else_e_body (x);
1152 else
1153 finally = gimple_eh_else_n_body (x);
1156 lower_eh_constructs_1 (state, &finally);
1158 for (gsi = gsi_start (finally); !gsi_end_p (gsi); gsi_next (&gsi))
1160 gimple stmt = gsi_stmt (gsi);
1161 if (LOCATION_LOCUS (gimple_location (stmt)) == UNKNOWN_LOCATION)
1163 tree block = gimple_block (stmt);
1164 gimple_set_location (stmt, gimple_location (tf->try_finally_expr));
1165 gimple_set_block (stmt, block);
1169 if (tf->may_throw)
1171 /* Only reachable via the exception edge. Add the given label to
1172 the head of the FINALLY block. Append a RESX at the end. */
1173 emit_post_landing_pad (&eh_seq, tf->region);
1174 gimple_seq_add_seq (&eh_seq, finally);
1175 emit_resx (&eh_seq, tf->region);
1176 return;
1179 if (tf->may_fallthru)
1181 /* Only reachable via the fallthru edge. Do nothing but let
1182 the two blocks run together; we'll fall out the bottom. */
1183 gimple_seq_add_seq (&tf->top_p_seq, finally);
1184 return;
1187 finally_label = create_artificial_label (loc);
1188 x = gimple_build_label (finally_label);
1189 gimple_seq_add_stmt (&tf->top_p_seq, x);
1191 gimple_seq_add_seq (&tf->top_p_seq, finally);
1193 q = tf->goto_queue;
1194 qe = q + tf->goto_queue_active;
1196 if (tf->may_return)
1198 /* Reachable by return expressions only. Redirect them. */
1199 for (; q < qe; ++q)
1200 do_return_redirection (q, finally_label, NULL);
1201 replace_goto_queue (tf);
1203 else
1205 /* Reachable by goto expressions only. Redirect them. */
1206 for (; q < qe; ++q)
1207 do_goto_redirection (q, finally_label, NULL, tf);
1208 replace_goto_queue (tf);
1210 if (tf->dest_array[0] == tf->fallthru_label)
1212 /* Reachable by goto to fallthru label only. Redirect it
1213 to the new label (already created, sadly), and do not
1214 emit the final branch out, or the fallthru label. */
1215 tf->fallthru_label = NULL;
1216 return;
1220 /* Place the original return/goto to the original destination
1221 immediately after the finally block. */
1222 x = tf->goto_queue[0].cont_stmt;
1223 gimple_seq_add_stmt (&tf->top_p_seq, x);
1224 maybe_record_in_goto_queue (state, x);
1227 /* A subroutine of lower_try_finally. There are multiple edges incoming
1228 and outgoing from the finally block. Implement this by duplicating the
1229 finally block for every destination. */
1231 static void
1232 lower_try_finally_copy (struct leh_state *state, struct leh_tf_state *tf)
1234 gimple_seq finally;
1235 gimple_seq new_stmt;
1236 gimple_seq seq;
1237 gimple x, eh_else;
1238 tree tmp;
1239 location_t tf_loc = gimple_location (tf->try_finally_expr);
1241 finally = gimple_try_cleanup (tf->top_p);
1243 /* Notice EH_ELSE, and simplify some of the remaining code
1244 by considering FINALLY to be the normal return path only. */
1245 eh_else = get_eh_else (finally);
1246 if (eh_else)
1247 finally = gimple_eh_else_n_body (eh_else);
1249 tf->top_p_seq = gimple_try_eval (tf->top_p);
1250 new_stmt = NULL;
1252 if (tf->may_fallthru)
1254 seq = lower_try_finally_dup_block (finally, state, tf_loc);
1255 lower_eh_constructs_1 (state, &seq);
1256 gimple_seq_add_seq (&new_stmt, seq);
1258 tmp = lower_try_finally_fallthru_label (tf);
1259 x = gimple_build_goto (tmp);
1260 gimple_set_location (x, tf_loc);
1261 gimple_seq_add_stmt (&new_stmt, x);
1264 if (tf->may_throw)
1266 /* We don't need to copy the EH path of EH_ELSE,
1267 since it is only emitted once. */
1268 if (eh_else)
1269 seq = gimple_eh_else_e_body (eh_else);
1270 else
1271 seq = lower_try_finally_dup_block (finally, state, tf_loc);
1272 lower_eh_constructs_1 (state, &seq);
1274 emit_post_landing_pad (&eh_seq, tf->region);
1275 gimple_seq_add_seq (&eh_seq, seq);
1276 emit_resx (&eh_seq, tf->region);
1279 if (tf->goto_queue)
1281 struct goto_queue_node *q, *qe;
1282 int return_index, index;
1283 struct labels_s
1285 struct goto_queue_node *q;
1286 tree label;
1287 } *labels;
1289 return_index = tf->dest_array.length ();
1290 labels = XCNEWVEC (struct labels_s, return_index + 1);
1292 q = tf->goto_queue;
1293 qe = q + tf->goto_queue_active;
1294 for (; q < qe; q++)
1296 index = q->index < 0 ? return_index : q->index;
1298 if (!labels[index].q)
1299 labels[index].q = q;
1302 for (index = 0; index < return_index + 1; index++)
1304 tree lab;
1306 q = labels[index].q;
1307 if (! q)
1308 continue;
1310 lab = labels[index].label
1311 = create_artificial_label (tf_loc);
1313 if (index == return_index)
1314 do_return_redirection (q, lab, NULL);
1315 else
1316 do_goto_redirection (q, lab, NULL, tf);
1318 x = gimple_build_label (lab);
1319 gimple_seq_add_stmt (&new_stmt, x);
1321 seq = lower_try_finally_dup_block (finally, state, q->location);
1322 lower_eh_constructs_1 (state, &seq);
1323 gimple_seq_add_seq (&new_stmt, seq);
1325 gimple_seq_add_stmt (&new_stmt, q->cont_stmt);
1326 maybe_record_in_goto_queue (state, q->cont_stmt);
1329 for (q = tf->goto_queue; q < qe; q++)
1331 tree lab;
1333 index = q->index < 0 ? return_index : q->index;
1335 if (labels[index].q == q)
1336 continue;
1338 lab = labels[index].label;
1340 if (index == return_index)
1341 do_return_redirection (q, lab, NULL);
1342 else
1343 do_goto_redirection (q, lab, NULL, tf);
1346 replace_goto_queue (tf);
1347 free (labels);
1350 /* Need to link new stmts after running replace_goto_queue due
1351 to not wanting to process the same goto stmts twice. */
1352 gimple_seq_add_seq (&tf->top_p_seq, new_stmt);
1355 /* A subroutine of lower_try_finally. There are multiple edges incoming
1356 and outgoing from the finally block. Implement this by instrumenting
1357 each incoming edge and creating a switch statement at the end of the
1358 finally block that branches to the appropriate destination. */
1360 static void
1361 lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf)
1363 struct goto_queue_node *q, *qe;
1364 tree finally_tmp, finally_label;
1365 int return_index, eh_index, fallthru_index;
1366 int nlabels, ndests, j, last_case_index;
1367 tree last_case;
1368 vec<tree> case_label_vec;
1369 gimple_seq switch_body = NULL;
1370 gimple x, eh_else;
1371 tree tmp;
1372 gimple switch_stmt;
1373 gimple_seq finally;
1374 struct pointer_map_t *cont_map = NULL;
1375 /* The location of the TRY_FINALLY stmt. */
1376 location_t tf_loc = gimple_location (tf->try_finally_expr);
1377 /* The location of the finally block. */
1378 location_t finally_loc;
1380 finally = gimple_try_cleanup (tf->top_p);
1381 eh_else = get_eh_else (finally);
1383 /* Mash the TRY block to the head of the chain. */
1384 tf->top_p_seq = gimple_try_eval (tf->top_p);
1386 /* The location of the finally is either the last stmt in the finally
1387 block or the location of the TRY_FINALLY itself. */
1388 x = gimple_seq_last_stmt (finally);
1389 finally_loc = x ? gimple_location (x) : tf_loc;
1391 /* Prepare for switch statement generation. */
1392 nlabels = tf->dest_array.length ();
1393 return_index = nlabels;
1394 eh_index = return_index + tf->may_return;
1395 fallthru_index = eh_index + (tf->may_throw && !eh_else);
1396 ndests = fallthru_index + tf->may_fallthru;
1398 finally_tmp = create_tmp_var (integer_type_node, "finally_tmp");
1399 finally_label = create_artificial_label (finally_loc);
1401 /* We use vec::quick_push on case_label_vec throughout this function,
1402 since we know the size in advance and allocate precisely as muce
1403 space as needed. */
1404 case_label_vec.create (ndests);
1405 last_case = NULL;
1406 last_case_index = 0;
1408 /* Begin inserting code for getting to the finally block. Things
1409 are done in this order to correspond to the sequence the code is
1410 laid out. */
1412 if (tf->may_fallthru)
1414 x = gimple_build_assign (finally_tmp,
1415 build_int_cst (integer_type_node,
1416 fallthru_index));
1417 gimple_seq_add_stmt (&tf->top_p_seq, x);
1419 tmp = build_int_cst (integer_type_node, fallthru_index);
1420 last_case = build_case_label (tmp, NULL,
1421 create_artificial_label (tf_loc));
1422 case_label_vec.quick_push (last_case);
1423 last_case_index++;
1425 x = gimple_build_label (CASE_LABEL (last_case));
1426 gimple_seq_add_stmt (&switch_body, x);
1428 tmp = lower_try_finally_fallthru_label (tf);
1429 x = gimple_build_goto (tmp);
1430 gimple_set_location (x, tf_loc);
1431 gimple_seq_add_stmt (&switch_body, x);
1434 /* For EH_ELSE, emit the exception path (plus resx) now, then
1435 subsequently we only need consider the normal path. */
1436 if (eh_else)
1438 if (tf->may_throw)
1440 finally = gimple_eh_else_e_body (eh_else);
1441 lower_eh_constructs_1 (state, &finally);
1443 emit_post_landing_pad (&eh_seq, tf->region);
1444 gimple_seq_add_seq (&eh_seq, finally);
1445 emit_resx (&eh_seq, tf->region);
1448 finally = gimple_eh_else_n_body (eh_else);
1450 else if (tf->may_throw)
1452 emit_post_landing_pad (&eh_seq, tf->region);
1454 x = gimple_build_assign (finally_tmp,
1455 build_int_cst (integer_type_node, eh_index));
1456 gimple_seq_add_stmt (&eh_seq, x);
1458 x = gimple_build_goto (finally_label);
1459 gimple_set_location (x, tf_loc);
1460 gimple_seq_add_stmt (&eh_seq, x);
1462 tmp = build_int_cst (integer_type_node, eh_index);
1463 last_case = build_case_label (tmp, NULL,
1464 create_artificial_label (tf_loc));
1465 case_label_vec.quick_push (last_case);
1466 last_case_index++;
1468 x = gimple_build_label (CASE_LABEL (last_case));
1469 gimple_seq_add_stmt (&eh_seq, x);
1470 emit_resx (&eh_seq, tf->region);
1473 x = gimple_build_label (finally_label);
1474 gimple_seq_add_stmt (&tf->top_p_seq, x);
1476 lower_eh_constructs_1 (state, &finally);
1477 gimple_seq_add_seq (&tf->top_p_seq, finally);
1479 /* Redirect each incoming goto edge. */
1480 q = tf->goto_queue;
1481 qe = q + tf->goto_queue_active;
1482 j = last_case_index + tf->may_return;
1483 /* Prepare the assignments to finally_tmp that are executed upon the
1484 entrance through a particular edge. */
1485 for (; q < qe; ++q)
1487 gimple_seq mod = NULL;
1488 int switch_id;
1489 unsigned int case_index;
1491 if (q->index < 0)
1493 x = gimple_build_assign (finally_tmp,
1494 build_int_cst (integer_type_node,
1495 return_index));
1496 gimple_seq_add_stmt (&mod, x);
1497 do_return_redirection (q, finally_label, mod);
1498 switch_id = return_index;
1500 else
1502 x = gimple_build_assign (finally_tmp,
1503 build_int_cst (integer_type_node, q->index));
1504 gimple_seq_add_stmt (&mod, x);
1505 do_goto_redirection (q, finally_label, mod, tf);
1506 switch_id = q->index;
1509 case_index = j + q->index;
1510 if (case_label_vec.length () <= case_index || !case_label_vec[case_index])
1512 tree case_lab;
1513 void **slot;
1514 tmp = build_int_cst (integer_type_node, switch_id);
1515 case_lab = build_case_label (tmp, NULL,
1516 create_artificial_label (tf_loc));
1517 /* We store the cont_stmt in the pointer map, so that we can recover
1518 it in the loop below. */
1519 if (!cont_map)
1520 cont_map = pointer_map_create ();
1521 slot = pointer_map_insert (cont_map, case_lab);
1522 *slot = q->cont_stmt;
1523 case_label_vec.quick_push (case_lab);
1526 for (j = last_case_index; j < last_case_index + nlabels; j++)
1528 gimple cont_stmt;
1529 void **slot;
1531 last_case = case_label_vec[j];
1533 gcc_assert (last_case);
1534 gcc_assert (cont_map);
1536 slot = pointer_map_contains (cont_map, last_case);
1537 gcc_assert (slot);
1538 cont_stmt = *(gimple *) slot;
1540 x = gimple_build_label (CASE_LABEL (last_case));
1541 gimple_seq_add_stmt (&switch_body, x);
1542 gimple_seq_add_stmt (&switch_body, cont_stmt);
1543 maybe_record_in_goto_queue (state, cont_stmt);
1545 if (cont_map)
1546 pointer_map_destroy (cont_map);
1548 replace_goto_queue (tf);
1550 /* Make sure that the last case is the default label, as one is required.
1551 Then sort the labels, which is also required in GIMPLE. */
1552 CASE_LOW (last_case) = NULL;
1553 sort_case_labels (case_label_vec);
1555 /* Build the switch statement, setting last_case to be the default
1556 label. */
1557 switch_stmt = gimple_build_switch (finally_tmp, last_case,
1558 case_label_vec);
1559 gimple_set_location (switch_stmt, finally_loc);
1561 /* Need to link SWITCH_STMT after running replace_goto_queue
1562 due to not wanting to process the same goto stmts twice. */
1563 gimple_seq_add_stmt (&tf->top_p_seq, switch_stmt);
1564 gimple_seq_add_seq (&tf->top_p_seq, switch_body);
1567 /* Decide whether or not we are going to duplicate the finally block.
1568 There are several considerations.
1570 First, if this is Java, then the finally block contains code
1571 written by the user. It has line numbers associated with it,
1572 so duplicating the block means it's difficult to set a breakpoint.
1573 Since controlling code generation via -g is verboten, we simply
1574 never duplicate code without optimization.
1576 Second, we'd like to prevent egregious code growth. One way to
1577 do this is to estimate the size of the finally block, multiply
1578 that by the number of copies we'd need to make, and compare against
1579 the estimate of the size of the switch machinery we'd have to add. */
1581 static bool
1582 decide_copy_try_finally (int ndests, bool may_throw, gimple_seq finally)
1584 int f_estimate, sw_estimate;
1585 gimple eh_else;
1587 /* If there's an EH_ELSE involved, the exception path is separate
1588 and really doesn't come into play for this computation. */
1589 eh_else = get_eh_else (finally);
1590 if (eh_else)
1592 ndests -= may_throw;
1593 finally = gimple_eh_else_n_body (eh_else);
1596 if (!optimize)
1598 gimple_stmt_iterator gsi;
1600 if (ndests == 1)
1601 return true;
1603 for (gsi = gsi_start (finally); !gsi_end_p (gsi); gsi_next (&gsi))
1605 gimple stmt = gsi_stmt (gsi);
1606 if (!is_gimple_debug (stmt) && !gimple_clobber_p (stmt))
1607 return false;
1609 return true;
1612 /* Finally estimate N times, plus N gotos. */
1613 f_estimate = count_insns_seq (finally, &eni_size_weights);
1614 f_estimate = (f_estimate + 1) * ndests;
1616 /* Switch statement (cost 10), N variable assignments, N gotos. */
1617 sw_estimate = 10 + 2 * ndests;
1619 /* Optimize for size clearly wants our best guess. */
1620 if (optimize_function_for_size_p (cfun))
1621 return f_estimate < sw_estimate;
1623 /* ??? These numbers are completely made up so far. */
1624 if (optimize > 1)
1625 return f_estimate < 100 || f_estimate < sw_estimate * 2;
1626 else
1627 return f_estimate < 40 || f_estimate * 2 < sw_estimate * 3;
1630 /* REG is the enclosing region for a possible cleanup region, or the region
1631 itself. Returns TRUE if such a region would be unreachable.
1633 Cleanup regions within a must-not-throw region aren't actually reachable
1634 even if there are throwing stmts within them, because the personality
1635 routine will call terminate before unwinding. */
1637 static bool
1638 cleanup_is_dead_in (eh_region reg)
1640 while (reg && reg->type == ERT_CLEANUP)
1641 reg = reg->outer;
1642 return (reg && reg->type == ERT_MUST_NOT_THROW);
1645 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1646 to a sequence of labels and blocks, plus the exception region trees
1647 that record all the magic. This is complicated by the need to
1648 arrange for the FINALLY block to be executed on all exits. */
1650 static gimple_seq
1651 lower_try_finally (struct leh_state *state, gimple tp)
1653 struct leh_tf_state this_tf;
1654 struct leh_state this_state;
1655 int ndests;
1656 gimple_seq old_eh_seq;
1658 /* Process the try block. */
1660 memset (&this_tf, 0, sizeof (this_tf));
1661 this_tf.try_finally_expr = tp;
1662 this_tf.top_p = tp;
1663 this_tf.outer = state;
1664 if (using_eh_for_cleanups_p () && !cleanup_is_dead_in (state->cur_region))
1666 this_tf.region = gen_eh_region_cleanup (state->cur_region);
1667 this_state.cur_region = this_tf.region;
1669 else
1671 this_tf.region = NULL;
1672 this_state.cur_region = state->cur_region;
1675 this_state.ehp_region = state->ehp_region;
1676 this_state.tf = &this_tf;
1678 old_eh_seq = eh_seq;
1679 eh_seq = NULL;
1681 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1683 /* Determine if the try block is escaped through the bottom. */
1684 this_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
1686 /* Determine if any exceptions are possible within the try block. */
1687 if (this_tf.region)
1688 this_tf.may_throw = eh_region_may_contain_throw (this_tf.region);
1689 if (this_tf.may_throw)
1690 honor_protect_cleanup_actions (state, &this_state, &this_tf);
1692 /* Determine how many edges (still) reach the finally block. Or rather,
1693 how many destinations are reached by the finally block. Use this to
1694 determine how we process the finally block itself. */
1696 ndests = this_tf.dest_array.length ();
1697 ndests += this_tf.may_fallthru;
1698 ndests += this_tf.may_return;
1699 ndests += this_tf.may_throw;
1701 /* If the FINALLY block is not reachable, dike it out. */
1702 if (ndests == 0)
1704 gimple_seq_add_seq (&this_tf.top_p_seq, gimple_try_eval (tp));
1705 gimple_try_set_cleanup (tp, NULL);
1707 /* If the finally block doesn't fall through, then any destination
1708 we might try to impose there isn't reached either. There may be
1709 some minor amount of cleanup and redirection still needed. */
1710 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp)))
1711 lower_try_finally_nofallthru (state, &this_tf);
1713 /* We can easily special-case redirection to a single destination. */
1714 else if (ndests == 1)
1715 lower_try_finally_onedest (state, &this_tf);
1716 else if (decide_copy_try_finally (ndests, this_tf.may_throw,
1717 gimple_try_cleanup (tp)))
1718 lower_try_finally_copy (state, &this_tf);
1719 else
1720 lower_try_finally_switch (state, &this_tf);
1722 /* If someone requested we add a label at the end of the transformed
1723 block, do so. */
1724 if (this_tf.fallthru_label)
1726 /* This must be reached only if ndests == 0. */
1727 gimple x = gimple_build_label (this_tf.fallthru_label);
1728 gimple_seq_add_stmt (&this_tf.top_p_seq, x);
1731 this_tf.dest_array.release ();
1732 free (this_tf.goto_queue);
1733 if (this_tf.goto_queue_map)
1734 pointer_map_destroy (this_tf.goto_queue_map);
1736 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1737 If there was no old eh_seq, then the append is trivially already done. */
1738 if (old_eh_seq)
1740 if (eh_seq == NULL)
1741 eh_seq = old_eh_seq;
1742 else
1744 gimple_seq new_eh_seq = eh_seq;
1745 eh_seq = old_eh_seq;
1746 gimple_seq_add_seq (&eh_seq, new_eh_seq);
1750 return this_tf.top_p_seq;
1753 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1754 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1755 exception region trees that records all the magic. */
1757 static gimple_seq
1758 lower_catch (struct leh_state *state, gimple tp)
1760 eh_region try_region = NULL;
1761 struct leh_state this_state = *state;
1762 gimple_stmt_iterator gsi;
1763 tree out_label;
1764 gimple_seq new_seq, cleanup;
1765 gimple x;
1766 location_t try_catch_loc = gimple_location (tp);
1768 if (flag_exceptions)
1770 try_region = gen_eh_region_try (state->cur_region);
1771 this_state.cur_region = try_region;
1774 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1776 if (!eh_region_may_contain_throw (try_region))
1777 return gimple_try_eval (tp);
1779 new_seq = NULL;
1780 emit_eh_dispatch (&new_seq, try_region);
1781 emit_resx (&new_seq, try_region);
1783 this_state.cur_region = state->cur_region;
1784 this_state.ehp_region = try_region;
1786 out_label = NULL;
1787 cleanup = gimple_try_cleanup (tp);
1788 for (gsi = gsi_start (cleanup);
1789 !gsi_end_p (gsi);
1790 gsi_next (&gsi))
1792 eh_catch c;
1793 gimple gcatch;
1794 gimple_seq handler;
1796 gcatch = gsi_stmt (gsi);
1797 c = gen_eh_region_catch (try_region, gimple_catch_types (gcatch));
1799 handler = gimple_catch_handler (gcatch);
1800 lower_eh_constructs_1 (&this_state, &handler);
1802 c->label = create_artificial_label (UNKNOWN_LOCATION);
1803 x = gimple_build_label (c->label);
1804 gimple_seq_add_stmt (&new_seq, x);
1806 gimple_seq_add_seq (&new_seq, handler);
1808 if (gimple_seq_may_fallthru (new_seq))
1810 if (!out_label)
1811 out_label = create_artificial_label (try_catch_loc);
1813 x = gimple_build_goto (out_label);
1814 gimple_seq_add_stmt (&new_seq, x);
1816 if (!c->type_list)
1817 break;
1820 gimple_try_set_cleanup (tp, new_seq);
1822 return frob_into_branch_around (tp, try_region, out_label);
1825 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1826 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1827 region trees that record all the magic. */
1829 static gimple_seq
1830 lower_eh_filter (struct leh_state *state, gimple tp)
1832 struct leh_state this_state = *state;
1833 eh_region this_region = NULL;
1834 gimple inner, x;
1835 gimple_seq new_seq;
1837 inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
1839 if (flag_exceptions)
1841 this_region = gen_eh_region_allowed (state->cur_region,
1842 gimple_eh_filter_types (inner));
1843 this_state.cur_region = this_region;
1846 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1848 if (!eh_region_may_contain_throw (this_region))
1849 return gimple_try_eval (tp);
1851 new_seq = NULL;
1852 this_state.cur_region = state->cur_region;
1853 this_state.ehp_region = this_region;
1855 emit_eh_dispatch (&new_seq, this_region);
1856 emit_resx (&new_seq, this_region);
1858 this_region->u.allowed.label = create_artificial_label (UNKNOWN_LOCATION);
1859 x = gimple_build_label (this_region->u.allowed.label);
1860 gimple_seq_add_stmt (&new_seq, x);
1862 lower_eh_constructs_1 (&this_state, gimple_eh_filter_failure_ptr (inner));
1863 gimple_seq_add_seq (&new_seq, gimple_eh_filter_failure (inner));
1865 gimple_try_set_cleanup (tp, new_seq);
1867 return frob_into_branch_around (tp, this_region, NULL);
1870 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1871 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1872 plus the exception region trees that record all the magic. */
1874 static gimple_seq
1875 lower_eh_must_not_throw (struct leh_state *state, gimple tp)
1877 struct leh_state this_state = *state;
1879 if (flag_exceptions)
1881 gimple inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
1882 eh_region this_region;
1884 this_region = gen_eh_region_must_not_throw (state->cur_region);
1885 this_region->u.must_not_throw.failure_decl
1886 = gimple_eh_must_not_throw_fndecl (inner);
1887 this_region->u.must_not_throw.failure_loc
1888 = LOCATION_LOCUS (gimple_location (tp));
1890 /* In order to get mangling applied to this decl, we must mark it
1891 used now. Otherwise, pass_ipa_free_lang_data won't think it
1892 needs to happen. */
1893 TREE_USED (this_region->u.must_not_throw.failure_decl) = 1;
1895 this_state.cur_region = this_region;
1898 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1900 return gimple_try_eval (tp);
1903 /* Implement a cleanup expression. This is similar to try-finally,
1904 except that we only execute the cleanup block for exception edges. */
1906 static gimple_seq
1907 lower_cleanup (struct leh_state *state, gimple tp)
1909 struct leh_state this_state = *state;
1910 eh_region this_region = NULL;
1911 struct leh_tf_state fake_tf;
1912 gimple_seq result;
1913 bool cleanup_dead = cleanup_is_dead_in (state->cur_region);
1915 if (flag_exceptions && !cleanup_dead)
1917 this_region = gen_eh_region_cleanup (state->cur_region);
1918 this_state.cur_region = this_region;
1921 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1923 if (cleanup_dead || !eh_region_may_contain_throw (this_region))
1924 return gimple_try_eval (tp);
1926 /* Build enough of a try-finally state so that we can reuse
1927 honor_protect_cleanup_actions. */
1928 memset (&fake_tf, 0, sizeof (fake_tf));
1929 fake_tf.top_p = fake_tf.try_finally_expr = tp;
1930 fake_tf.outer = state;
1931 fake_tf.region = this_region;
1932 fake_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
1933 fake_tf.may_throw = true;
1935 honor_protect_cleanup_actions (state, NULL, &fake_tf);
1937 if (fake_tf.may_throw)
1939 /* In this case honor_protect_cleanup_actions had nothing to do,
1940 and we should process this normally. */
1941 lower_eh_constructs_1 (state, gimple_try_cleanup_ptr (tp));
1942 result = frob_into_branch_around (tp, this_region,
1943 fake_tf.fallthru_label);
1945 else
1947 /* In this case honor_protect_cleanup_actions did nearly all of
1948 the work. All we have left is to append the fallthru_label. */
1950 result = gimple_try_eval (tp);
1951 if (fake_tf.fallthru_label)
1953 gimple x = gimple_build_label (fake_tf.fallthru_label);
1954 gimple_seq_add_stmt (&result, x);
1957 return result;
1960 /* Main loop for lowering eh constructs. Also moves gsi to the next
1961 statement. */
1963 static void
1964 lower_eh_constructs_2 (struct leh_state *state, gimple_stmt_iterator *gsi)
1966 gimple_seq replace;
1967 gimple x;
1968 gimple stmt = gsi_stmt (*gsi);
1970 switch (gimple_code (stmt))
1972 case GIMPLE_CALL:
1974 tree fndecl = gimple_call_fndecl (stmt);
1975 tree rhs, lhs;
1977 if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
1978 switch (DECL_FUNCTION_CODE (fndecl))
1980 case BUILT_IN_EH_POINTER:
1981 /* The front end may have generated a call to
1982 __builtin_eh_pointer (0) within a catch region. Replace
1983 this zero argument with the current catch region number. */
1984 if (state->ehp_region)
1986 tree nr = build_int_cst (integer_type_node,
1987 state->ehp_region->index);
1988 gimple_call_set_arg (stmt, 0, nr);
1990 else
1992 /* The user has dome something silly. Remove it. */
1993 rhs = null_pointer_node;
1994 goto do_replace;
1996 break;
1998 case BUILT_IN_EH_FILTER:
1999 /* ??? This should never appear, but since it's a builtin it
2000 is accessible to abuse by users. Just remove it and
2001 replace the use with the arbitrary value zero. */
2002 rhs = build_int_cst (TREE_TYPE (TREE_TYPE (fndecl)), 0);
2003 do_replace:
2004 lhs = gimple_call_lhs (stmt);
2005 x = gimple_build_assign (lhs, rhs);
2006 gsi_insert_before (gsi, x, GSI_SAME_STMT);
2007 /* FALLTHRU */
2009 case BUILT_IN_EH_COPY_VALUES:
2010 /* Likewise this should not appear. Remove it. */
2011 gsi_remove (gsi, true);
2012 return;
2014 default:
2015 break;
2018 /* FALLTHRU */
2020 case GIMPLE_ASSIGN:
2021 /* If the stmt can throw use a new temporary for the assignment
2022 to a LHS. This makes sure the old value of the LHS is
2023 available on the EH edge. Only do so for statements that
2024 potentially fall through (no noreturn calls e.g.), otherwise
2025 this new assignment might create fake fallthru regions. */
2026 if (stmt_could_throw_p (stmt)
2027 && gimple_has_lhs (stmt)
2028 && gimple_stmt_may_fallthru (stmt)
2029 && !tree_could_throw_p (gimple_get_lhs (stmt))
2030 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt))))
2032 tree lhs = gimple_get_lhs (stmt);
2033 tree tmp = create_tmp_var (TREE_TYPE (lhs), NULL);
2034 gimple s = gimple_build_assign (lhs, tmp);
2035 gimple_set_location (s, gimple_location (stmt));
2036 gimple_set_block (s, gimple_block (stmt));
2037 gimple_set_lhs (stmt, tmp);
2038 if (TREE_CODE (TREE_TYPE (tmp)) == COMPLEX_TYPE
2039 || TREE_CODE (TREE_TYPE (tmp)) == VECTOR_TYPE)
2040 DECL_GIMPLE_REG_P (tmp) = 1;
2041 gsi_insert_after (gsi, s, GSI_SAME_STMT);
2043 /* Look for things that can throw exceptions, and record them. */
2044 if (state->cur_region && stmt_could_throw_p (stmt))
2046 record_stmt_eh_region (state->cur_region, stmt);
2047 note_eh_region_may_contain_throw (state->cur_region);
2049 break;
2051 case GIMPLE_COND:
2052 case GIMPLE_GOTO:
2053 case GIMPLE_RETURN:
2054 maybe_record_in_goto_queue (state, stmt);
2055 break;
2057 case GIMPLE_SWITCH:
2058 verify_norecord_switch_expr (state, stmt);
2059 break;
2061 case GIMPLE_TRY:
2062 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
2063 replace = lower_try_finally (state, stmt);
2064 else
2066 x = gimple_seq_first_stmt (gimple_try_cleanup (stmt));
2067 if (!x)
2069 replace = gimple_try_eval (stmt);
2070 lower_eh_constructs_1 (state, &replace);
2072 else
2073 switch (gimple_code (x))
2075 case GIMPLE_CATCH:
2076 replace = lower_catch (state, stmt);
2077 break;
2078 case GIMPLE_EH_FILTER:
2079 replace = lower_eh_filter (state, stmt);
2080 break;
2081 case GIMPLE_EH_MUST_NOT_THROW:
2082 replace = lower_eh_must_not_throw (state, stmt);
2083 break;
2084 case GIMPLE_EH_ELSE:
2085 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2086 gcc_unreachable ();
2087 default:
2088 replace = lower_cleanup (state, stmt);
2089 break;
2093 /* Remove the old stmt and insert the transformed sequence
2094 instead. */
2095 gsi_insert_seq_before (gsi, replace, GSI_SAME_STMT);
2096 gsi_remove (gsi, true);
2098 /* Return since we don't want gsi_next () */
2099 return;
2101 case GIMPLE_EH_ELSE:
2102 /* We should be eliminating this in lower_try_finally et al. */
2103 gcc_unreachable ();
2105 default:
2106 /* A type, a decl, or some kind of statement that we're not
2107 interested in. Don't walk them. */
2108 break;
2111 gsi_next (gsi);
2114 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2116 static void
2117 lower_eh_constructs_1 (struct leh_state *state, gimple_seq *pseq)
2119 gimple_stmt_iterator gsi;
2120 for (gsi = gsi_start (*pseq); !gsi_end_p (gsi);)
2121 lower_eh_constructs_2 (state, &gsi);
2124 static unsigned int
2125 lower_eh_constructs (void)
2127 struct leh_state null_state;
2128 gimple_seq bodyp;
2130 bodyp = gimple_body (current_function_decl);
2131 if (bodyp == NULL)
2132 return 0;
2134 finally_tree.create (31);
2135 eh_region_may_contain_throw_map = BITMAP_ALLOC (NULL);
2136 memset (&null_state, 0, sizeof (null_state));
2138 collect_finally_tree_1 (bodyp, NULL);
2139 lower_eh_constructs_1 (&null_state, &bodyp);
2140 gimple_set_body (current_function_decl, bodyp);
2142 /* We assume there's a return statement, or something, at the end of
2143 the function, and thus ploping the EH sequence afterward won't
2144 change anything. */
2145 gcc_assert (!gimple_seq_may_fallthru (bodyp));
2146 gimple_seq_add_seq (&bodyp, eh_seq);
2148 /* We assume that since BODYP already existed, adding EH_SEQ to it
2149 didn't change its value, and we don't have to re-set the function. */
2150 gcc_assert (bodyp == gimple_body (current_function_decl));
2152 finally_tree.dispose ();
2153 BITMAP_FREE (eh_region_may_contain_throw_map);
2154 eh_seq = NULL;
2156 /* If this function needs a language specific EH personality routine
2157 and the frontend didn't already set one do so now. */
2158 if (function_needs_eh_personality (cfun) == eh_personality_lang
2159 && !DECL_FUNCTION_PERSONALITY (current_function_decl))
2160 DECL_FUNCTION_PERSONALITY (current_function_decl)
2161 = lang_hooks.eh_personality ();
2163 return 0;
2166 namespace {
2168 const pass_data pass_data_lower_eh =
2170 GIMPLE_PASS, /* type */
2171 "eh", /* name */
2172 OPTGROUP_NONE, /* optinfo_flags */
2173 false, /* has_gate */
2174 true, /* has_execute */
2175 TV_TREE_EH, /* tv_id */
2176 PROP_gimple_lcf, /* properties_required */
2177 PROP_gimple_leh, /* properties_provided */
2178 0, /* properties_destroyed */
2179 0, /* todo_flags_start */
2180 0, /* todo_flags_finish */
2183 class pass_lower_eh : public gimple_opt_pass
2185 public:
2186 pass_lower_eh (gcc::context *ctxt)
2187 : gimple_opt_pass (pass_data_lower_eh, ctxt)
2190 /* opt_pass methods: */
2191 unsigned int execute () { return lower_eh_constructs (); }
2193 }; // class pass_lower_eh
2195 } // anon namespace
2197 gimple_opt_pass *
2198 make_pass_lower_eh (gcc::context *ctxt)
2200 return new pass_lower_eh (ctxt);
2203 /* Create the multiple edges from an EH_DISPATCH statement to all of
2204 the possible handlers for its EH region. Return true if there's
2205 no fallthru edge; false if there is. */
2207 bool
2208 make_eh_dispatch_edges (gimple stmt)
2210 eh_region r;
2211 eh_catch c;
2212 basic_block src, dst;
2214 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
2215 src = gimple_bb (stmt);
2217 switch (r->type)
2219 case ERT_TRY:
2220 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
2222 dst = label_to_block (c->label);
2223 make_edge (src, dst, 0);
2225 /* A catch-all handler doesn't have a fallthru. */
2226 if (c->type_list == NULL)
2227 return false;
2229 break;
2231 case ERT_ALLOWED_EXCEPTIONS:
2232 dst = label_to_block (r->u.allowed.label);
2233 make_edge (src, dst, 0);
2234 break;
2236 default:
2237 gcc_unreachable ();
2240 return true;
2243 /* Create the single EH edge from STMT to its nearest landing pad,
2244 if there is such a landing pad within the current function. */
2246 void
2247 make_eh_edges (gimple stmt)
2249 basic_block src, dst;
2250 eh_landing_pad lp;
2251 int lp_nr;
2253 lp_nr = lookup_stmt_eh_lp (stmt);
2254 if (lp_nr <= 0)
2255 return;
2257 lp = get_eh_landing_pad_from_number (lp_nr);
2258 gcc_assert (lp != NULL);
2260 src = gimple_bb (stmt);
2261 dst = label_to_block (lp->post_landing_pad);
2262 make_edge (src, dst, EDGE_EH);
2265 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2266 do not actually perform the final edge redirection.
2268 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2269 we intend to change the destination EH region as well; this means
2270 EH_LANDING_PAD_NR must already be set on the destination block label.
2271 If false, we're being called from generic cfg manipulation code and we
2272 should preserve our place within the region tree. */
2274 static void
2275 redirect_eh_edge_1 (edge edge_in, basic_block new_bb, bool change_region)
2277 eh_landing_pad old_lp, new_lp;
2278 basic_block old_bb;
2279 gimple throw_stmt;
2280 int old_lp_nr, new_lp_nr;
2281 tree old_label, new_label;
2282 edge_iterator ei;
2283 edge e;
2285 old_bb = edge_in->dest;
2286 old_label = gimple_block_label (old_bb);
2287 old_lp_nr = EH_LANDING_PAD_NR (old_label);
2288 gcc_assert (old_lp_nr > 0);
2289 old_lp = get_eh_landing_pad_from_number (old_lp_nr);
2291 throw_stmt = last_stmt (edge_in->src);
2292 gcc_assert (lookup_stmt_eh_lp (throw_stmt) == old_lp_nr);
2294 new_label = gimple_block_label (new_bb);
2296 /* Look for an existing region that might be using NEW_BB already. */
2297 new_lp_nr = EH_LANDING_PAD_NR (new_label);
2298 if (new_lp_nr)
2300 new_lp = get_eh_landing_pad_from_number (new_lp_nr);
2301 gcc_assert (new_lp);
2303 /* Unless CHANGE_REGION is true, the new and old landing pad
2304 had better be associated with the same EH region. */
2305 gcc_assert (change_region || new_lp->region == old_lp->region);
2307 else
2309 new_lp = NULL;
2310 gcc_assert (!change_region);
2313 /* Notice when we redirect the last EH edge away from OLD_BB. */
2314 FOR_EACH_EDGE (e, ei, old_bb->preds)
2315 if (e != edge_in && (e->flags & EDGE_EH))
2316 break;
2318 if (new_lp)
2320 /* NEW_LP already exists. If there are still edges into OLD_LP,
2321 there's nothing to do with the EH tree. If there are no more
2322 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2323 If CHANGE_REGION is true, then our caller is expecting to remove
2324 the landing pad. */
2325 if (e == NULL && !change_region)
2326 remove_eh_landing_pad (old_lp);
2328 else
2330 /* No correct landing pad exists. If there are no more edges
2331 into OLD_LP, then we can simply re-use the existing landing pad.
2332 Otherwise, we have to create a new landing pad. */
2333 if (e == NULL)
2335 EH_LANDING_PAD_NR (old_lp->post_landing_pad) = 0;
2336 new_lp = old_lp;
2338 else
2339 new_lp = gen_eh_landing_pad (old_lp->region);
2340 new_lp->post_landing_pad = new_label;
2341 EH_LANDING_PAD_NR (new_label) = new_lp->index;
2344 /* Maybe move the throwing statement to the new region. */
2345 if (old_lp != new_lp)
2347 remove_stmt_from_eh_lp (throw_stmt);
2348 add_stmt_to_eh_lp (throw_stmt, new_lp->index);
2352 /* Redirect EH edge E to NEW_BB. */
2354 edge
2355 redirect_eh_edge (edge edge_in, basic_block new_bb)
2357 redirect_eh_edge_1 (edge_in, new_bb, false);
2358 return ssa_redirect_edge (edge_in, new_bb);
2361 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2362 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2363 The actual edge update will happen in the caller. */
2365 void
2366 redirect_eh_dispatch_edge (gimple stmt, edge e, basic_block new_bb)
2368 tree new_lab = gimple_block_label (new_bb);
2369 bool any_changed = false;
2370 basic_block old_bb;
2371 eh_region r;
2372 eh_catch c;
2374 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
2375 switch (r->type)
2377 case ERT_TRY:
2378 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
2380 old_bb = label_to_block (c->label);
2381 if (old_bb == e->dest)
2383 c->label = new_lab;
2384 any_changed = true;
2387 break;
2389 case ERT_ALLOWED_EXCEPTIONS:
2390 old_bb = label_to_block (r->u.allowed.label);
2391 gcc_assert (old_bb == e->dest);
2392 r->u.allowed.label = new_lab;
2393 any_changed = true;
2394 break;
2396 default:
2397 gcc_unreachable ();
2400 gcc_assert (any_changed);
2403 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2405 bool
2406 operation_could_trap_helper_p (enum tree_code op,
2407 bool fp_operation,
2408 bool honor_trapv,
2409 bool honor_nans,
2410 bool honor_snans,
2411 tree divisor,
2412 bool *handled)
2414 *handled = true;
2415 switch (op)
2417 case TRUNC_DIV_EXPR:
2418 case CEIL_DIV_EXPR:
2419 case FLOOR_DIV_EXPR:
2420 case ROUND_DIV_EXPR:
2421 case EXACT_DIV_EXPR:
2422 case CEIL_MOD_EXPR:
2423 case FLOOR_MOD_EXPR:
2424 case ROUND_MOD_EXPR:
2425 case TRUNC_MOD_EXPR:
2426 case RDIV_EXPR:
2427 if (honor_snans || honor_trapv)
2428 return true;
2429 if (fp_operation)
2430 return flag_trapping_math;
2431 if (!TREE_CONSTANT (divisor) || integer_zerop (divisor))
2432 return true;
2433 return false;
2435 case LT_EXPR:
2436 case LE_EXPR:
2437 case GT_EXPR:
2438 case GE_EXPR:
2439 case LTGT_EXPR:
2440 /* Some floating point comparisons may trap. */
2441 return honor_nans;
2443 case EQ_EXPR:
2444 case NE_EXPR:
2445 case UNORDERED_EXPR:
2446 case ORDERED_EXPR:
2447 case UNLT_EXPR:
2448 case UNLE_EXPR:
2449 case UNGT_EXPR:
2450 case UNGE_EXPR:
2451 case UNEQ_EXPR:
2452 return honor_snans;
2454 case CONVERT_EXPR:
2455 case FIX_TRUNC_EXPR:
2456 /* Conversion of floating point might trap. */
2457 return honor_nans;
2459 case NEGATE_EXPR:
2460 case ABS_EXPR:
2461 case CONJ_EXPR:
2462 /* These operations don't trap with floating point. */
2463 if (honor_trapv)
2464 return true;
2465 return false;
2467 case PLUS_EXPR:
2468 case MINUS_EXPR:
2469 case MULT_EXPR:
2470 /* Any floating arithmetic may trap. */
2471 if (fp_operation && flag_trapping_math)
2472 return true;
2473 if (honor_trapv)
2474 return true;
2475 return false;
2477 case COMPLEX_EXPR:
2478 case CONSTRUCTOR:
2479 /* Constructing an object cannot trap. */
2480 return false;
2482 default:
2483 /* Any floating arithmetic may trap. */
2484 if (fp_operation && flag_trapping_math)
2485 return true;
2487 *handled = false;
2488 return false;
2492 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2493 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2494 type operands that may trap. If OP is a division operator, DIVISOR contains
2495 the value of the divisor. */
2497 bool
2498 operation_could_trap_p (enum tree_code op, bool fp_operation, bool honor_trapv,
2499 tree divisor)
2501 bool honor_nans = (fp_operation && flag_trapping_math
2502 && !flag_finite_math_only);
2503 bool honor_snans = fp_operation && flag_signaling_nans != 0;
2504 bool handled;
2506 if (TREE_CODE_CLASS (op) != tcc_comparison
2507 && TREE_CODE_CLASS (op) != tcc_unary
2508 && TREE_CODE_CLASS (op) != tcc_binary)
2509 return false;
2511 return operation_could_trap_helper_p (op, fp_operation, honor_trapv,
2512 honor_nans, honor_snans, divisor,
2513 &handled);
2517 /* Returns true if it is possible to prove that the index of
2518 an array access REF (an ARRAY_REF expression) falls into the
2519 array bounds. */
2521 static bool
2522 in_array_bounds_p (tree ref)
2524 tree idx = TREE_OPERAND (ref, 1);
2525 tree min, max;
2527 if (TREE_CODE (idx) != INTEGER_CST)
2528 return false;
2530 min = array_ref_low_bound (ref);
2531 max = array_ref_up_bound (ref);
2532 if (!min
2533 || !max
2534 || TREE_CODE (min) != INTEGER_CST
2535 || TREE_CODE (max) != INTEGER_CST)
2536 return false;
2538 if (tree_int_cst_lt (idx, min)
2539 || tree_int_cst_lt (max, idx))
2540 return false;
2542 return true;
2545 /* Returns true if it is possible to prove that the range of
2546 an array access REF (an ARRAY_RANGE_REF expression) falls
2547 into the array bounds. */
2549 static bool
2550 range_in_array_bounds_p (tree ref)
2552 tree domain_type = TYPE_DOMAIN (TREE_TYPE (ref));
2553 tree range_min, range_max, min, max;
2555 range_min = TYPE_MIN_VALUE (domain_type);
2556 range_max = TYPE_MAX_VALUE (domain_type);
2557 if (!range_min
2558 || !range_max
2559 || TREE_CODE (range_min) != INTEGER_CST
2560 || TREE_CODE (range_max) != INTEGER_CST)
2561 return false;
2563 min = array_ref_low_bound (ref);
2564 max = array_ref_up_bound (ref);
2565 if (!min
2566 || !max
2567 || TREE_CODE (min) != INTEGER_CST
2568 || TREE_CODE (max) != INTEGER_CST)
2569 return false;
2571 if (tree_int_cst_lt (range_min, min)
2572 || tree_int_cst_lt (max, range_max))
2573 return false;
2575 return true;
2578 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2579 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2580 This routine expects only GIMPLE lhs or rhs input. */
2582 bool
2583 tree_could_trap_p (tree expr)
2585 enum tree_code code;
2586 bool fp_operation = false;
2587 bool honor_trapv = false;
2588 tree t, base, div = NULL_TREE;
2590 if (!expr)
2591 return false;
2593 code = TREE_CODE (expr);
2594 t = TREE_TYPE (expr);
2596 if (t)
2598 if (COMPARISON_CLASS_P (expr))
2599 fp_operation = FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0)));
2600 else
2601 fp_operation = FLOAT_TYPE_P (t);
2602 honor_trapv = INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t);
2605 if (TREE_CODE_CLASS (code) == tcc_binary)
2606 div = TREE_OPERAND (expr, 1);
2607 if (operation_could_trap_p (code, fp_operation, honor_trapv, div))
2608 return true;
2610 restart:
2611 switch (code)
2613 case COMPONENT_REF:
2614 case REALPART_EXPR:
2615 case IMAGPART_EXPR:
2616 case BIT_FIELD_REF:
2617 case VIEW_CONVERT_EXPR:
2618 case WITH_SIZE_EXPR:
2619 expr = TREE_OPERAND (expr, 0);
2620 code = TREE_CODE (expr);
2621 goto restart;
2623 case ARRAY_RANGE_REF:
2624 base = TREE_OPERAND (expr, 0);
2625 if (tree_could_trap_p (base))
2626 return true;
2627 if (TREE_THIS_NOTRAP (expr))
2628 return false;
2629 return !range_in_array_bounds_p (expr);
2631 case ARRAY_REF:
2632 base = TREE_OPERAND (expr, 0);
2633 if (tree_could_trap_p (base))
2634 return true;
2635 if (TREE_THIS_NOTRAP (expr))
2636 return false;
2637 return !in_array_bounds_p (expr);
2639 case TARGET_MEM_REF:
2640 case MEM_REF:
2641 if (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR
2642 && tree_could_trap_p (TREE_OPERAND (TREE_OPERAND (expr, 0), 0)))
2643 return true;
2644 if (TREE_THIS_NOTRAP (expr))
2645 return false;
2646 /* We cannot prove that the access is in-bounds when we have
2647 variable-index TARGET_MEM_REFs. */
2648 if (code == TARGET_MEM_REF
2649 && (TMR_INDEX (expr) || TMR_INDEX2 (expr)))
2650 return true;
2651 if (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR)
2653 tree base = TREE_OPERAND (TREE_OPERAND (expr, 0), 0);
2654 double_int off = mem_ref_offset (expr);
2655 if (off.is_negative ())
2656 return true;
2657 if (TREE_CODE (base) == STRING_CST)
2658 return double_int::from_uhwi (TREE_STRING_LENGTH (base)).ule (off);
2659 else if (DECL_SIZE_UNIT (base) == NULL_TREE
2660 || TREE_CODE (DECL_SIZE_UNIT (base)) != INTEGER_CST
2661 || tree_to_double_int (DECL_SIZE_UNIT (base)).ule (off))
2662 return true;
2663 /* Now we are sure the first byte of the access is inside
2664 the object. */
2665 return false;
2667 return true;
2669 case INDIRECT_REF:
2670 return !TREE_THIS_NOTRAP (expr);
2672 case ASM_EXPR:
2673 return TREE_THIS_VOLATILE (expr);
2675 case CALL_EXPR:
2676 t = get_callee_fndecl (expr);
2677 /* Assume that calls to weak functions may trap. */
2678 if (!t || !DECL_P (t))
2679 return true;
2680 if (DECL_WEAK (t))
2681 return tree_could_trap_p (t);
2682 return false;
2684 case FUNCTION_DECL:
2685 /* Assume that accesses to weak functions may trap, unless we know
2686 they are certainly defined in current TU or in some other
2687 LTO partition. */
2688 if (DECL_WEAK (expr) && !DECL_COMDAT (expr))
2690 struct cgraph_node *node;
2691 if (!DECL_EXTERNAL (expr))
2692 return false;
2693 node = cgraph_function_node (cgraph_get_node (expr), NULL);
2694 if (node && node->in_other_partition)
2695 return false;
2696 return true;
2698 return false;
2700 case VAR_DECL:
2701 /* Assume that accesses to weak vars may trap, unless we know
2702 they are certainly defined in current TU or in some other
2703 LTO partition. */
2704 if (DECL_WEAK (expr) && !DECL_COMDAT (expr))
2706 varpool_node *node;
2707 if (!DECL_EXTERNAL (expr))
2708 return false;
2709 node = varpool_variable_node (varpool_get_node (expr), NULL);
2710 if (node && node->in_other_partition)
2711 return false;
2712 return true;
2714 return false;
2716 default:
2717 return false;
2722 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2723 an assignment or a conditional) may throw. */
2725 static bool
2726 stmt_could_throw_1_p (gimple stmt)
2728 enum tree_code code = gimple_expr_code (stmt);
2729 bool honor_nans = false;
2730 bool honor_snans = false;
2731 bool fp_operation = false;
2732 bool honor_trapv = false;
2733 tree t;
2734 size_t i;
2735 bool handled, ret;
2737 if (TREE_CODE_CLASS (code) == tcc_comparison
2738 || TREE_CODE_CLASS (code) == tcc_unary
2739 || TREE_CODE_CLASS (code) == tcc_binary)
2741 if (is_gimple_assign (stmt)
2742 && TREE_CODE_CLASS (code) == tcc_comparison)
2743 t = TREE_TYPE (gimple_assign_rhs1 (stmt));
2744 else if (gimple_code (stmt) == GIMPLE_COND)
2745 t = TREE_TYPE (gimple_cond_lhs (stmt));
2746 else
2747 t = gimple_expr_type (stmt);
2748 fp_operation = FLOAT_TYPE_P (t);
2749 if (fp_operation)
2751 honor_nans = flag_trapping_math && !flag_finite_math_only;
2752 honor_snans = flag_signaling_nans != 0;
2754 else if (INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t))
2755 honor_trapv = true;
2758 /* Check if the main expression may trap. */
2759 t = is_gimple_assign (stmt) ? gimple_assign_rhs2 (stmt) : NULL;
2760 ret = operation_could_trap_helper_p (code, fp_operation, honor_trapv,
2761 honor_nans, honor_snans, t,
2762 &handled);
2763 if (handled)
2764 return ret;
2766 /* If the expression does not trap, see if any of the individual operands may
2767 trap. */
2768 for (i = 0; i < gimple_num_ops (stmt); i++)
2769 if (tree_could_trap_p (gimple_op (stmt, i)))
2770 return true;
2772 return false;
2776 /* Return true if statement STMT could throw an exception. */
2778 bool
2779 stmt_could_throw_p (gimple stmt)
2781 if (!flag_exceptions)
2782 return false;
2784 /* The only statements that can throw an exception are assignments,
2785 conditionals, calls, resx, and asms. */
2786 switch (gimple_code (stmt))
2788 case GIMPLE_RESX:
2789 return true;
2791 case GIMPLE_CALL:
2792 return !gimple_call_nothrow_p (stmt);
2794 case GIMPLE_ASSIGN:
2795 case GIMPLE_COND:
2796 if (!cfun->can_throw_non_call_exceptions)
2797 return false;
2798 return stmt_could_throw_1_p (stmt);
2800 case GIMPLE_ASM:
2801 if (!cfun->can_throw_non_call_exceptions)
2802 return false;
2803 return gimple_asm_volatile_p (stmt);
2805 default:
2806 return false;
2811 /* Return true if expression T could throw an exception. */
2813 bool
2814 tree_could_throw_p (tree t)
2816 if (!flag_exceptions)
2817 return false;
2818 if (TREE_CODE (t) == MODIFY_EXPR)
2820 if (cfun->can_throw_non_call_exceptions
2821 && tree_could_trap_p (TREE_OPERAND (t, 0)))
2822 return true;
2823 t = TREE_OPERAND (t, 1);
2826 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2827 t = TREE_OPERAND (t, 0);
2828 if (TREE_CODE (t) == CALL_EXPR)
2829 return (call_expr_flags (t) & ECF_NOTHROW) == 0;
2830 if (cfun->can_throw_non_call_exceptions)
2831 return tree_could_trap_p (t);
2832 return false;
2835 /* Return true if STMT can throw an exception that is not caught within
2836 the current function (CFUN). */
2838 bool
2839 stmt_can_throw_external (gimple stmt)
2841 int lp_nr;
2843 if (!stmt_could_throw_p (stmt))
2844 return false;
2846 lp_nr = lookup_stmt_eh_lp (stmt);
2847 return lp_nr == 0;
2850 /* Return true if STMT can throw an exception that is caught within
2851 the current function (CFUN). */
2853 bool
2854 stmt_can_throw_internal (gimple stmt)
2856 int lp_nr;
2858 if (!stmt_could_throw_p (stmt))
2859 return false;
2861 lp_nr = lookup_stmt_eh_lp (stmt);
2862 return lp_nr > 0;
2865 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2866 remove any entry it might have from the EH table. Return true if
2867 any change was made. */
2869 bool
2870 maybe_clean_eh_stmt_fn (struct function *ifun, gimple stmt)
2872 if (stmt_could_throw_p (stmt))
2873 return false;
2874 return remove_stmt_from_eh_lp_fn (ifun, stmt);
2877 /* Likewise, but always use the current function. */
2879 bool
2880 maybe_clean_eh_stmt (gimple stmt)
2882 return maybe_clean_eh_stmt_fn (cfun, stmt);
2885 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2886 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2887 in the table if it should be in there. Return TRUE if a replacement was
2888 done that my require an EH edge purge. */
2890 bool
2891 maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt)
2893 int lp_nr = lookup_stmt_eh_lp (old_stmt);
2895 if (lp_nr != 0)
2897 bool new_stmt_could_throw = stmt_could_throw_p (new_stmt);
2899 if (new_stmt == old_stmt && new_stmt_could_throw)
2900 return false;
2902 remove_stmt_from_eh_lp (old_stmt);
2903 if (new_stmt_could_throw)
2905 add_stmt_to_eh_lp (new_stmt, lp_nr);
2906 return false;
2908 else
2909 return true;
2912 return false;
2915 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
2916 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2917 operand is the return value of duplicate_eh_regions. */
2919 bool
2920 maybe_duplicate_eh_stmt_fn (struct function *new_fun, gimple new_stmt,
2921 struct function *old_fun, gimple old_stmt,
2922 struct pointer_map_t *map, int default_lp_nr)
2924 int old_lp_nr, new_lp_nr;
2925 void **slot;
2927 if (!stmt_could_throw_p (new_stmt))
2928 return false;
2930 old_lp_nr = lookup_stmt_eh_lp_fn (old_fun, old_stmt);
2931 if (old_lp_nr == 0)
2933 if (default_lp_nr == 0)
2934 return false;
2935 new_lp_nr = default_lp_nr;
2937 else if (old_lp_nr > 0)
2939 eh_landing_pad old_lp, new_lp;
2941 old_lp = (*old_fun->eh->lp_array)[old_lp_nr];
2942 slot = pointer_map_contains (map, old_lp);
2943 new_lp = (eh_landing_pad) *slot;
2944 new_lp_nr = new_lp->index;
2946 else
2948 eh_region old_r, new_r;
2950 old_r = (*old_fun->eh->region_array)[-old_lp_nr];
2951 slot = pointer_map_contains (map, old_r);
2952 new_r = (eh_region) *slot;
2953 new_lp_nr = -new_r->index;
2956 add_stmt_to_eh_lp_fn (new_fun, new_stmt, new_lp_nr);
2957 return true;
2960 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2961 and thus no remapping is required. */
2963 bool
2964 maybe_duplicate_eh_stmt (gimple new_stmt, gimple old_stmt)
2966 int lp_nr;
2968 if (!stmt_could_throw_p (new_stmt))
2969 return false;
2971 lp_nr = lookup_stmt_eh_lp (old_stmt);
2972 if (lp_nr == 0)
2973 return false;
2975 add_stmt_to_eh_lp (new_stmt, lp_nr);
2976 return true;
2979 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2980 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2981 this only handles handlers consisting of a single call, as that's the
2982 important case for C++: a destructor call for a particular object showing
2983 up in multiple handlers. */
2985 static bool
2986 same_handler_p (gimple_seq oneh, gimple_seq twoh)
2988 gimple_stmt_iterator gsi;
2989 gimple ones, twos;
2990 unsigned int ai;
2992 gsi = gsi_start (oneh);
2993 if (!gsi_one_before_end_p (gsi))
2994 return false;
2995 ones = gsi_stmt (gsi);
2997 gsi = gsi_start (twoh);
2998 if (!gsi_one_before_end_p (gsi))
2999 return false;
3000 twos = gsi_stmt (gsi);
3002 if (!is_gimple_call (ones)
3003 || !is_gimple_call (twos)
3004 || gimple_call_lhs (ones)
3005 || gimple_call_lhs (twos)
3006 || gimple_call_chain (ones)
3007 || gimple_call_chain (twos)
3008 || !gimple_call_same_target_p (ones, twos)
3009 || gimple_call_num_args (ones) != gimple_call_num_args (twos))
3010 return false;
3012 for (ai = 0; ai < gimple_call_num_args (ones); ++ai)
3013 if (!operand_equal_p (gimple_call_arg (ones, ai),
3014 gimple_call_arg (twos, ai), 0))
3015 return false;
3017 return true;
3020 /* Optimize
3021 try { A() } finally { try { ~B() } catch { ~A() } }
3022 try { ... } finally { ~A() }
3023 into
3024 try { A() } catch { ~B() }
3025 try { ~B() ... } finally { ~A() }
3027 This occurs frequently in C++, where A is a local variable and B is a
3028 temporary used in the initializer for A. */
3030 static void
3031 optimize_double_finally (gimple one, gimple two)
3033 gimple oneh;
3034 gimple_stmt_iterator gsi;
3035 gimple_seq cleanup;
3037 cleanup = gimple_try_cleanup (one);
3038 gsi = gsi_start (cleanup);
3039 if (!gsi_one_before_end_p (gsi))
3040 return;
3042 oneh = gsi_stmt (gsi);
3043 if (gimple_code (oneh) != GIMPLE_TRY
3044 || gimple_try_kind (oneh) != GIMPLE_TRY_CATCH)
3045 return;
3047 if (same_handler_p (gimple_try_cleanup (oneh), gimple_try_cleanup (two)))
3049 gimple_seq seq = gimple_try_eval (oneh);
3051 gimple_try_set_cleanup (one, seq);
3052 gimple_try_set_kind (one, GIMPLE_TRY_CATCH);
3053 seq = copy_gimple_seq_and_replace_locals (seq);
3054 gimple_seq_add_seq (&seq, gimple_try_eval (two));
3055 gimple_try_set_eval (two, seq);
3059 /* Perform EH refactoring optimizations that are simpler to do when code
3060 flow has been lowered but EH structures haven't. */
3062 static void
3063 refactor_eh_r (gimple_seq seq)
3065 gimple_stmt_iterator gsi;
3066 gimple one, two;
3068 one = NULL;
3069 two = NULL;
3070 gsi = gsi_start (seq);
3071 while (1)
3073 one = two;
3074 if (gsi_end_p (gsi))
3075 two = NULL;
3076 else
3077 two = gsi_stmt (gsi);
3078 if (one
3079 && two
3080 && gimple_code (one) == GIMPLE_TRY
3081 && gimple_code (two) == GIMPLE_TRY
3082 && gimple_try_kind (one) == GIMPLE_TRY_FINALLY
3083 && gimple_try_kind (two) == GIMPLE_TRY_FINALLY)
3084 optimize_double_finally (one, two);
3085 if (one)
3086 switch (gimple_code (one))
3088 case GIMPLE_TRY:
3089 refactor_eh_r (gimple_try_eval (one));
3090 refactor_eh_r (gimple_try_cleanup (one));
3091 break;
3092 case GIMPLE_CATCH:
3093 refactor_eh_r (gimple_catch_handler (one));
3094 break;
3095 case GIMPLE_EH_FILTER:
3096 refactor_eh_r (gimple_eh_filter_failure (one));
3097 break;
3098 case GIMPLE_EH_ELSE:
3099 refactor_eh_r (gimple_eh_else_n_body (one));
3100 refactor_eh_r (gimple_eh_else_e_body (one));
3101 break;
3102 default:
3103 break;
3105 if (two)
3106 gsi_next (&gsi);
3107 else
3108 break;
3112 static unsigned
3113 refactor_eh (void)
3115 refactor_eh_r (gimple_body (current_function_decl));
3116 return 0;
3119 static bool
3120 gate_refactor_eh (void)
3122 return flag_exceptions != 0;
3125 namespace {
3127 const pass_data pass_data_refactor_eh =
3129 GIMPLE_PASS, /* type */
3130 "ehopt", /* name */
3131 OPTGROUP_NONE, /* optinfo_flags */
3132 true, /* has_gate */
3133 true, /* has_execute */
3134 TV_TREE_EH, /* tv_id */
3135 PROP_gimple_lcf, /* properties_required */
3136 0, /* properties_provided */
3137 0, /* properties_destroyed */
3138 0, /* todo_flags_start */
3139 0, /* todo_flags_finish */
3142 class pass_refactor_eh : public gimple_opt_pass
3144 public:
3145 pass_refactor_eh (gcc::context *ctxt)
3146 : gimple_opt_pass (pass_data_refactor_eh, ctxt)
3149 /* opt_pass methods: */
3150 bool gate () { return gate_refactor_eh (); }
3151 unsigned int execute () { return refactor_eh (); }
3153 }; // class pass_refactor_eh
3155 } // anon namespace
3157 gimple_opt_pass *
3158 make_pass_refactor_eh (gcc::context *ctxt)
3160 return new pass_refactor_eh (ctxt);
3163 /* At the end of gimple optimization, we can lower RESX. */
3165 static bool
3166 lower_resx (basic_block bb, gimple stmt, struct pointer_map_t *mnt_map)
3168 int lp_nr;
3169 eh_region src_r, dst_r;
3170 gimple_stmt_iterator gsi;
3171 gimple x;
3172 tree fn, src_nr;
3173 bool ret = false;
3175 lp_nr = lookup_stmt_eh_lp (stmt);
3176 if (lp_nr != 0)
3177 dst_r = get_eh_region_from_lp_number (lp_nr);
3178 else
3179 dst_r = NULL;
3181 src_r = get_eh_region_from_number (gimple_resx_region (stmt));
3182 gsi = gsi_last_bb (bb);
3184 if (src_r == NULL)
3186 /* We can wind up with no source region when pass_cleanup_eh shows
3187 that there are no entries into an eh region and deletes it, but
3188 then the block that contains the resx isn't removed. This can
3189 happen without optimization when the switch statement created by
3190 lower_try_finally_switch isn't simplified to remove the eh case.
3192 Resolve this by expanding the resx node to an abort. */
3194 fn = builtin_decl_implicit (BUILT_IN_TRAP);
3195 x = gimple_build_call (fn, 0);
3196 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3198 while (EDGE_COUNT (bb->succs) > 0)
3199 remove_edge (EDGE_SUCC (bb, 0));
3201 else if (dst_r)
3203 /* When we have a destination region, we resolve this by copying
3204 the excptr and filter values into place, and changing the edge
3205 to immediately after the landing pad. */
3206 edge e;
3208 if (lp_nr < 0)
3210 basic_block new_bb;
3211 void **slot;
3212 tree lab;
3214 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3215 the failure decl into a new block, if needed. */
3216 gcc_assert (dst_r->type == ERT_MUST_NOT_THROW);
3218 slot = pointer_map_contains (mnt_map, dst_r);
3219 if (slot == NULL)
3221 gimple_stmt_iterator gsi2;
3223 new_bb = create_empty_bb (bb);
3224 if (current_loops)
3225 add_bb_to_loop (new_bb, bb->loop_father);
3226 lab = gimple_block_label (new_bb);
3227 gsi2 = gsi_start_bb (new_bb);
3229 fn = dst_r->u.must_not_throw.failure_decl;
3230 x = gimple_build_call (fn, 0);
3231 gimple_set_location (x, dst_r->u.must_not_throw.failure_loc);
3232 gsi_insert_after (&gsi2, x, GSI_CONTINUE_LINKING);
3234 slot = pointer_map_insert (mnt_map, dst_r);
3235 *slot = lab;
3237 else
3239 lab = (tree) *slot;
3240 new_bb = label_to_block (lab);
3243 gcc_assert (EDGE_COUNT (bb->succs) == 0);
3244 e = make_edge (bb, new_bb, EDGE_FALLTHRU);
3245 e->count = bb->count;
3246 e->probability = REG_BR_PROB_BASE;
3248 else
3250 edge_iterator ei;
3251 tree dst_nr = build_int_cst (integer_type_node, dst_r->index);
3253 fn = builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES);
3254 src_nr = build_int_cst (integer_type_node, src_r->index);
3255 x = gimple_build_call (fn, 2, dst_nr, src_nr);
3256 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3258 /* Update the flags for the outgoing edge. */
3259 e = single_succ_edge (bb);
3260 gcc_assert (e->flags & EDGE_EH);
3261 e->flags = (e->flags & ~EDGE_EH) | EDGE_FALLTHRU;
3263 /* If there are no more EH users of the landing pad, delete it. */
3264 FOR_EACH_EDGE (e, ei, e->dest->preds)
3265 if (e->flags & EDGE_EH)
3266 break;
3267 if (e == NULL)
3269 eh_landing_pad lp = get_eh_landing_pad_from_number (lp_nr);
3270 remove_eh_landing_pad (lp);
3274 ret = true;
3276 else
3278 tree var;
3280 /* When we don't have a destination region, this exception escapes
3281 up the call chain. We resolve this by generating a call to the
3282 _Unwind_Resume library function. */
3284 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3285 with no arguments for C++ and Java. Check for that. */
3286 if (src_r->use_cxa_end_cleanup)
3288 fn = builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP);
3289 x = gimple_build_call (fn, 0);
3290 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3292 else
3294 fn = builtin_decl_implicit (BUILT_IN_EH_POINTER);
3295 src_nr = build_int_cst (integer_type_node, src_r->index);
3296 x = gimple_build_call (fn, 1, src_nr);
3297 var = create_tmp_var (ptr_type_node, NULL);
3298 var = make_ssa_name (var, x);
3299 gimple_call_set_lhs (x, var);
3300 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3302 fn = builtin_decl_implicit (BUILT_IN_UNWIND_RESUME);
3303 x = gimple_build_call (fn, 1, var);
3304 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3307 gcc_assert (EDGE_COUNT (bb->succs) == 0);
3310 gsi_remove (&gsi, true);
3312 return ret;
3315 static unsigned
3316 execute_lower_resx (void)
3318 basic_block bb;
3319 struct pointer_map_t *mnt_map;
3320 bool dominance_invalidated = false;
3321 bool any_rewritten = false;
3323 mnt_map = pointer_map_create ();
3325 FOR_EACH_BB_FN (bb, cfun)
3327 gimple last = last_stmt (bb);
3328 if (last && is_gimple_resx (last))
3330 dominance_invalidated |= lower_resx (bb, last, mnt_map);
3331 any_rewritten = true;
3335 pointer_map_destroy (mnt_map);
3337 if (dominance_invalidated)
3339 free_dominance_info (CDI_DOMINATORS);
3340 free_dominance_info (CDI_POST_DOMINATORS);
3343 return any_rewritten ? TODO_update_ssa_only_virtuals : 0;
3346 static bool
3347 gate_lower_resx (void)
3349 return flag_exceptions != 0;
3352 namespace {
3354 const pass_data pass_data_lower_resx =
3356 GIMPLE_PASS, /* type */
3357 "resx", /* name */
3358 OPTGROUP_NONE, /* optinfo_flags */
3359 true, /* has_gate */
3360 true, /* has_execute */
3361 TV_TREE_EH, /* tv_id */
3362 PROP_gimple_lcf, /* properties_required */
3363 0, /* properties_provided */
3364 0, /* properties_destroyed */
3365 0, /* todo_flags_start */
3366 TODO_verify_flow, /* todo_flags_finish */
3369 class pass_lower_resx : public gimple_opt_pass
3371 public:
3372 pass_lower_resx (gcc::context *ctxt)
3373 : gimple_opt_pass (pass_data_lower_resx, ctxt)
3376 /* opt_pass methods: */
3377 bool gate () { return gate_lower_resx (); }
3378 unsigned int execute () { return execute_lower_resx (); }
3380 }; // class pass_lower_resx
3382 } // anon namespace
3384 gimple_opt_pass *
3385 make_pass_lower_resx (gcc::context *ctxt)
3387 return new pass_lower_resx (ctxt);
3390 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3391 external throw. */
3393 static void
3394 optimize_clobbers (basic_block bb)
3396 gimple_stmt_iterator gsi = gsi_last_bb (bb);
3397 bool any_clobbers = false;
3398 bool seen_stack_restore = false;
3399 edge_iterator ei;
3400 edge e;
3402 /* Only optimize anything if the bb contains at least one clobber,
3403 ends with resx (checked by caller), optionally contains some
3404 debug stmts or labels, or at most one __builtin_stack_restore
3405 call, and has an incoming EH edge. */
3406 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3408 gimple stmt = gsi_stmt (gsi);
3409 if (is_gimple_debug (stmt))
3410 continue;
3411 if (gimple_clobber_p (stmt))
3413 any_clobbers = true;
3414 continue;
3416 if (!seen_stack_restore
3417 && gimple_call_builtin_p (stmt, BUILT_IN_STACK_RESTORE))
3419 seen_stack_restore = true;
3420 continue;
3422 if (gimple_code (stmt) == GIMPLE_LABEL)
3423 break;
3424 return;
3426 if (!any_clobbers)
3427 return;
3428 FOR_EACH_EDGE (e, ei, bb->preds)
3429 if (e->flags & EDGE_EH)
3430 break;
3431 if (e == NULL)
3432 return;
3433 gsi = gsi_last_bb (bb);
3434 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3436 gimple stmt = gsi_stmt (gsi);
3437 if (!gimple_clobber_p (stmt))
3438 continue;
3439 unlink_stmt_vdef (stmt);
3440 gsi_remove (&gsi, true);
3441 release_defs (stmt);
3445 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3446 internal throw to successor BB. */
3448 static int
3449 sink_clobbers (basic_block bb)
3451 edge e;
3452 edge_iterator ei;
3453 gimple_stmt_iterator gsi, dgsi;
3454 basic_block succbb;
3455 bool any_clobbers = false;
3456 unsigned todo = 0;
3458 /* Only optimize if BB has a single EH successor and
3459 all predecessor edges are EH too. */
3460 if (!single_succ_p (bb)
3461 || (single_succ_edge (bb)->flags & EDGE_EH) == 0)
3462 return 0;
3464 FOR_EACH_EDGE (e, ei, bb->preds)
3466 if ((e->flags & EDGE_EH) == 0)
3467 return 0;
3470 /* And BB contains only CLOBBER stmts before the final
3471 RESX. */
3472 gsi = gsi_last_bb (bb);
3473 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3475 gimple stmt = gsi_stmt (gsi);
3476 if (is_gimple_debug (stmt))
3477 continue;
3478 if (gimple_code (stmt) == GIMPLE_LABEL)
3479 break;
3480 if (!gimple_clobber_p (stmt))
3481 return 0;
3482 any_clobbers = true;
3484 if (!any_clobbers)
3485 return 0;
3487 edge succe = single_succ_edge (bb);
3488 succbb = succe->dest;
3490 /* See if there is a virtual PHI node to take an updated virtual
3491 operand from. */
3492 gimple vphi = NULL;
3493 tree vuse = NULL_TREE;
3494 for (gsi = gsi_start_phis (succbb); !gsi_end_p (gsi); gsi_next (&gsi))
3496 tree res = gimple_phi_result (gsi_stmt (gsi));
3497 if (virtual_operand_p (res))
3499 vphi = gsi_stmt (gsi);
3500 vuse = res;
3501 break;
3505 dgsi = gsi_after_labels (succbb);
3506 gsi = gsi_last_bb (bb);
3507 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3509 gimple stmt = gsi_stmt (gsi);
3510 tree lhs;
3511 if (is_gimple_debug (stmt))
3512 continue;
3513 if (gimple_code (stmt) == GIMPLE_LABEL)
3514 break;
3515 lhs = gimple_assign_lhs (stmt);
3516 /* Unfortunately we don't have dominance info updated at this
3517 point, so checking if
3518 dominated_by_p (CDI_DOMINATORS, succbb,
3519 gimple_bb (SSA_NAME_DEF_STMT (TREE_OPERAND (lhs, 0)))
3520 would be too costly. Thus, avoid sinking any clobbers that
3521 refer to non-(D) SSA_NAMEs. */
3522 if (TREE_CODE (lhs) == MEM_REF
3523 && TREE_CODE (TREE_OPERAND (lhs, 0)) == SSA_NAME
3524 && !SSA_NAME_IS_DEFAULT_DEF (TREE_OPERAND (lhs, 0)))
3526 unlink_stmt_vdef (stmt);
3527 gsi_remove (&gsi, true);
3528 release_defs (stmt);
3529 continue;
3532 /* As we do not change stmt order when sinking across a
3533 forwarder edge we can keep virtual operands in place. */
3534 gsi_remove (&gsi, false);
3535 gsi_insert_before (&dgsi, stmt, GSI_NEW_STMT);
3537 /* But adjust virtual operands if we sunk across a PHI node. */
3538 if (vuse)
3540 gimple use_stmt;
3541 imm_use_iterator iter;
3542 use_operand_p use_p;
3543 FOR_EACH_IMM_USE_STMT (use_stmt, iter, vuse)
3544 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
3545 SET_USE (use_p, gimple_vdef (stmt));
3546 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse))
3548 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (stmt)) = 1;
3549 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse) = 0;
3551 /* Adjust the incoming virtual operand. */
3552 SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (vphi, succe), gimple_vuse (stmt));
3553 SET_USE (gimple_vuse_op (stmt), vuse);
3555 /* If there isn't a single predecessor but no virtual PHI node
3556 arrange for virtual operands to be renamed. */
3557 else if (gimple_vuse_op (stmt) != NULL_USE_OPERAND_P
3558 && !single_pred_p (succbb))
3560 /* In this case there will be no use of the VDEF of this stmt.
3561 ??? Unless this is a secondary opportunity and we have not
3562 removed unreachable blocks yet, so we cannot assert this.
3563 Which also means we will end up renaming too many times. */
3564 SET_USE (gimple_vuse_op (stmt), gimple_vop (cfun));
3565 mark_virtual_operands_for_renaming (cfun);
3566 todo |= TODO_update_ssa_only_virtuals;
3570 return todo;
3573 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3574 we have found some duplicate labels and removed some edges. */
3576 static bool
3577 lower_eh_dispatch (basic_block src, gimple stmt)
3579 gimple_stmt_iterator gsi;
3580 int region_nr;
3581 eh_region r;
3582 tree filter, fn;
3583 gimple x;
3584 bool redirected = false;
3586 region_nr = gimple_eh_dispatch_region (stmt);
3587 r = get_eh_region_from_number (region_nr);
3589 gsi = gsi_last_bb (src);
3591 switch (r->type)
3593 case ERT_TRY:
3595 auto_vec<tree> labels;
3596 tree default_label = NULL;
3597 eh_catch c;
3598 edge_iterator ei;
3599 edge e;
3600 struct pointer_set_t *seen_values = pointer_set_create ();
3602 /* Collect the labels for a switch. Zero the post_landing_pad
3603 field becase we'll no longer have anything keeping these labels
3604 in existence and the optimizer will be free to merge these
3605 blocks at will. */
3606 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
3608 tree tp_node, flt_node, lab = c->label;
3609 bool have_label = false;
3611 c->label = NULL;
3612 tp_node = c->type_list;
3613 flt_node = c->filter_list;
3615 if (tp_node == NULL)
3617 default_label = lab;
3618 break;
3622 /* Filter out duplicate labels that arise when this handler
3623 is shadowed by an earlier one. When no labels are
3624 attached to the handler anymore, we remove
3625 the corresponding edge and then we delete unreachable
3626 blocks at the end of this pass. */
3627 if (! pointer_set_contains (seen_values, TREE_VALUE (flt_node)))
3629 tree t = build_case_label (TREE_VALUE (flt_node),
3630 NULL, lab);
3631 labels.safe_push (t);
3632 pointer_set_insert (seen_values, TREE_VALUE (flt_node));
3633 have_label = true;
3636 tp_node = TREE_CHAIN (tp_node);
3637 flt_node = TREE_CHAIN (flt_node);
3639 while (tp_node);
3640 if (! have_label)
3642 remove_edge (find_edge (src, label_to_block (lab)));
3643 redirected = true;
3647 /* Clean up the edge flags. */
3648 FOR_EACH_EDGE (e, ei, src->succs)
3650 if (e->flags & EDGE_FALLTHRU)
3652 /* If there was no catch-all, use the fallthru edge. */
3653 if (default_label == NULL)
3654 default_label = gimple_block_label (e->dest);
3655 e->flags &= ~EDGE_FALLTHRU;
3658 gcc_assert (default_label != NULL);
3660 /* Don't generate a switch if there's only a default case.
3661 This is common in the form of try { A; } catch (...) { B; }. */
3662 if (!labels.exists ())
3664 e = single_succ_edge (src);
3665 e->flags |= EDGE_FALLTHRU;
3667 else
3669 fn = builtin_decl_implicit (BUILT_IN_EH_FILTER);
3670 x = gimple_build_call (fn, 1, build_int_cst (integer_type_node,
3671 region_nr));
3672 filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
3673 filter = make_ssa_name (filter, x);
3674 gimple_call_set_lhs (x, filter);
3675 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3677 /* Turn the default label into a default case. */
3678 default_label = build_case_label (NULL, NULL, default_label);
3679 sort_case_labels (labels);
3681 x = gimple_build_switch (filter, default_label, labels);
3682 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3684 pointer_set_destroy (seen_values);
3686 break;
3688 case ERT_ALLOWED_EXCEPTIONS:
3690 edge b_e = BRANCH_EDGE (src);
3691 edge f_e = FALLTHRU_EDGE (src);
3693 fn = builtin_decl_implicit (BUILT_IN_EH_FILTER);
3694 x = gimple_build_call (fn, 1, build_int_cst (integer_type_node,
3695 region_nr));
3696 filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
3697 filter = make_ssa_name (filter, x);
3698 gimple_call_set_lhs (x, filter);
3699 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3701 r->u.allowed.label = NULL;
3702 x = gimple_build_cond (EQ_EXPR, filter,
3703 build_int_cst (TREE_TYPE (filter),
3704 r->u.allowed.filter),
3705 NULL_TREE, NULL_TREE);
3706 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3708 b_e->flags = b_e->flags | EDGE_TRUE_VALUE;
3709 f_e->flags = (f_e->flags & ~EDGE_FALLTHRU) | EDGE_FALSE_VALUE;
3711 break;
3713 default:
3714 gcc_unreachable ();
3717 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3718 gsi_remove (&gsi, true);
3719 return redirected;
3722 static unsigned
3723 execute_lower_eh_dispatch (void)
3725 basic_block bb;
3726 int flags = 0;
3727 bool redirected = false;
3729 assign_filter_values ();
3731 FOR_EACH_BB_FN (bb, cfun)
3733 gimple last = last_stmt (bb);
3734 if (last == NULL)
3735 continue;
3736 if (gimple_code (last) == GIMPLE_EH_DISPATCH)
3738 redirected |= lower_eh_dispatch (bb, last);
3739 flags |= TODO_update_ssa_only_virtuals;
3741 else if (gimple_code (last) == GIMPLE_RESX)
3743 if (stmt_can_throw_external (last))
3744 optimize_clobbers (bb);
3745 else
3746 flags |= sink_clobbers (bb);
3750 if (redirected)
3751 delete_unreachable_blocks ();
3752 return flags;
3755 static bool
3756 gate_lower_eh_dispatch (void)
3758 return cfun->eh->region_tree != NULL;
3761 namespace {
3763 const pass_data pass_data_lower_eh_dispatch =
3765 GIMPLE_PASS, /* type */
3766 "ehdisp", /* name */
3767 OPTGROUP_NONE, /* optinfo_flags */
3768 true, /* has_gate */
3769 true, /* has_execute */
3770 TV_TREE_EH, /* tv_id */
3771 PROP_gimple_lcf, /* properties_required */
3772 0, /* properties_provided */
3773 0, /* properties_destroyed */
3774 0, /* todo_flags_start */
3775 TODO_verify_flow, /* todo_flags_finish */
3778 class pass_lower_eh_dispatch : public gimple_opt_pass
3780 public:
3781 pass_lower_eh_dispatch (gcc::context *ctxt)
3782 : gimple_opt_pass (pass_data_lower_eh_dispatch, ctxt)
3785 /* opt_pass methods: */
3786 bool gate () { return gate_lower_eh_dispatch (); }
3787 unsigned int execute () { return execute_lower_eh_dispatch (); }
3789 }; // class pass_lower_eh_dispatch
3791 } // anon namespace
3793 gimple_opt_pass *
3794 make_pass_lower_eh_dispatch (gcc::context *ctxt)
3796 return new pass_lower_eh_dispatch (ctxt);
3799 /* Walk statements, see what regions and, optionally, landing pads
3800 are really referenced.
3802 Returns in R_REACHABLEP an sbitmap with bits set for reachable regions,
3803 and in LP_REACHABLE an sbitmap with bits set for reachable landing pads.
3805 Passing NULL for LP_REACHABLE is valid, in this case only reachable
3806 regions are marked.
3808 The caller is responsible for freeing the returned sbitmaps. */
3810 static void
3811 mark_reachable_handlers (sbitmap *r_reachablep, sbitmap *lp_reachablep)
3813 sbitmap r_reachable, lp_reachable;
3814 basic_block bb;
3815 bool mark_landing_pads = (lp_reachablep != NULL);
3816 gcc_checking_assert (r_reachablep != NULL);
3818 r_reachable = sbitmap_alloc (cfun->eh->region_array->length ());
3819 bitmap_clear (r_reachable);
3820 *r_reachablep = r_reachable;
3822 if (mark_landing_pads)
3824 lp_reachable = sbitmap_alloc (cfun->eh->lp_array->length ());
3825 bitmap_clear (lp_reachable);
3826 *lp_reachablep = lp_reachable;
3828 else
3829 lp_reachable = NULL;
3831 FOR_EACH_BB_FN (bb, cfun)
3833 gimple_stmt_iterator gsi;
3835 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
3837 gimple stmt = gsi_stmt (gsi);
3839 if (mark_landing_pads)
3841 int lp_nr = lookup_stmt_eh_lp (stmt);
3843 /* Negative LP numbers are MUST_NOT_THROW regions which
3844 are not considered BB enders. */
3845 if (lp_nr < 0)
3846 bitmap_set_bit (r_reachable, -lp_nr);
3848 /* Positive LP numbers are real landing pads, and BB enders. */
3849 else if (lp_nr > 0)
3851 gcc_assert (gsi_one_before_end_p (gsi));
3852 eh_region region = get_eh_region_from_lp_number (lp_nr);
3853 bitmap_set_bit (r_reachable, region->index);
3854 bitmap_set_bit (lp_reachable, lp_nr);
3858 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3859 switch (gimple_code (stmt))
3861 case GIMPLE_RESX:
3862 bitmap_set_bit (r_reachable, gimple_resx_region (stmt));
3863 break;
3864 case GIMPLE_EH_DISPATCH:
3865 bitmap_set_bit (r_reachable, gimple_eh_dispatch_region (stmt));
3866 break;
3867 default:
3868 break;
3874 /* Remove unreachable handlers and unreachable landing pads. */
3876 static void
3877 remove_unreachable_handlers (void)
3879 sbitmap r_reachable, lp_reachable;
3880 eh_region region;
3881 eh_landing_pad lp;
3882 unsigned i;
3884 mark_reachable_handlers (&r_reachable, &lp_reachable);
3886 if (dump_file)
3888 fprintf (dump_file, "Before removal of unreachable regions:\n");
3889 dump_eh_tree (dump_file, cfun);
3890 fprintf (dump_file, "Reachable regions: ");
3891 dump_bitmap_file (dump_file, r_reachable);
3892 fprintf (dump_file, "Reachable landing pads: ");
3893 dump_bitmap_file (dump_file, lp_reachable);
3896 if (dump_file)
3898 FOR_EACH_VEC_SAFE_ELT (cfun->eh->region_array, i, region)
3899 if (region && !bitmap_bit_p (r_reachable, region->index))
3900 fprintf (dump_file,
3901 "Removing unreachable region %d\n",
3902 region->index);
3905 remove_unreachable_eh_regions (r_reachable);
3907 FOR_EACH_VEC_SAFE_ELT (cfun->eh->lp_array, i, lp)
3908 if (lp && !bitmap_bit_p (lp_reachable, lp->index))
3910 if (dump_file)
3911 fprintf (dump_file,
3912 "Removing unreachable landing pad %d\n",
3913 lp->index);
3914 remove_eh_landing_pad (lp);
3917 if (dump_file)
3919 fprintf (dump_file, "\n\nAfter removal of unreachable regions:\n");
3920 dump_eh_tree (dump_file, cfun);
3921 fprintf (dump_file, "\n\n");
3924 sbitmap_free (r_reachable);
3925 sbitmap_free (lp_reachable);
3927 #ifdef ENABLE_CHECKING
3928 verify_eh_tree (cfun);
3929 #endif
3932 /* Remove unreachable handlers if any landing pads have been removed after
3933 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3935 void
3936 maybe_remove_unreachable_handlers (void)
3938 eh_landing_pad lp;
3939 unsigned i;
3941 if (cfun->eh == NULL)
3942 return;
3944 FOR_EACH_VEC_SAFE_ELT (cfun->eh->lp_array, i, lp)
3945 if (lp && lp->post_landing_pad)
3947 if (label_to_block (lp->post_landing_pad) == NULL)
3949 remove_unreachable_handlers ();
3950 return;
3955 /* Remove regions that do not have landing pads. This assumes
3956 that remove_unreachable_handlers has already been run, and
3957 that we've just manipulated the landing pads since then.
3959 Preserve regions with landing pads and regions that prevent
3960 exceptions from propagating further, even if these regions
3961 are not reachable. */
3963 static void
3964 remove_unreachable_handlers_no_lp (void)
3966 eh_region region;
3967 sbitmap r_reachable;
3968 unsigned i;
3970 mark_reachable_handlers (&r_reachable, /*lp_reachablep=*/NULL);
3972 FOR_EACH_VEC_SAFE_ELT (cfun->eh->region_array, i, region)
3974 if (! region)
3975 continue;
3977 if (region->landing_pads != NULL
3978 || region->type == ERT_MUST_NOT_THROW)
3979 bitmap_set_bit (r_reachable, region->index);
3981 if (dump_file
3982 && !bitmap_bit_p (r_reachable, region->index))
3983 fprintf (dump_file,
3984 "Removing unreachable region %d\n",
3985 region->index);
3988 remove_unreachable_eh_regions (r_reachable);
3990 sbitmap_free (r_reachable);
3993 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3994 optimisticaly split all sorts of edges, including EH edges. The
3995 optimization passes in between may not have needed them; if not,
3996 we should undo the split.
3998 Recognize this case by having one EH edge incoming to the BB and
3999 one normal edge outgoing; BB should be empty apart from the
4000 post_landing_pad label.
4002 Note that this is slightly different from the empty handler case
4003 handled by cleanup_empty_eh, in that the actual handler may yet
4004 have actual code but the landing pad has been separated from the
4005 handler. As such, cleanup_empty_eh relies on this transformation
4006 having been done first. */
4008 static bool
4009 unsplit_eh (eh_landing_pad lp)
4011 basic_block bb = label_to_block (lp->post_landing_pad);
4012 gimple_stmt_iterator gsi;
4013 edge e_in, e_out;
4015 /* Quickly check the edge counts on BB for singularity. */
4016 if (!single_pred_p (bb) || !single_succ_p (bb))
4017 return false;
4018 e_in = single_pred_edge (bb);
4019 e_out = single_succ_edge (bb);
4021 /* Input edge must be EH and output edge must be normal. */
4022 if ((e_in->flags & EDGE_EH) == 0 || (e_out->flags & EDGE_EH) != 0)
4023 return false;
4025 /* The block must be empty except for the labels and debug insns. */
4026 gsi = gsi_after_labels (bb);
4027 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
4028 gsi_next_nondebug (&gsi);
4029 if (!gsi_end_p (gsi))
4030 return false;
4032 /* The destination block must not already have a landing pad
4033 for a different region. */
4034 for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
4036 gimple stmt = gsi_stmt (gsi);
4037 tree lab;
4038 int lp_nr;
4040 if (gimple_code (stmt) != GIMPLE_LABEL)
4041 break;
4042 lab = gimple_label_label (stmt);
4043 lp_nr = EH_LANDING_PAD_NR (lab);
4044 if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
4045 return false;
4048 /* The new destination block must not already be a destination of
4049 the source block, lest we merge fallthru and eh edges and get
4050 all sorts of confused. */
4051 if (find_edge (e_in->src, e_out->dest))
4052 return false;
4054 /* ??? We can get degenerate phis due to cfg cleanups. I would have
4055 thought this should have been cleaned up by a phicprop pass, but
4056 that doesn't appear to handle virtuals. Propagate by hand. */
4057 if (!gimple_seq_empty_p (phi_nodes (bb)))
4059 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
4061 gimple use_stmt, phi = gsi_stmt (gsi);
4062 tree lhs = gimple_phi_result (phi);
4063 tree rhs = gimple_phi_arg_def (phi, 0);
4064 use_operand_p use_p;
4065 imm_use_iterator iter;
4067 FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
4069 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
4070 SET_USE (use_p, rhs);
4073 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
4074 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
4076 remove_phi_node (&gsi, true);
4080 if (dump_file && (dump_flags & TDF_DETAILS))
4081 fprintf (dump_file, "Unsplit EH landing pad %d to block %i.\n",
4082 lp->index, e_out->dest->index);
4084 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
4085 a successor edge, humor it. But do the real CFG change with the
4086 predecessor of E_OUT in order to preserve the ordering of arguments
4087 to the PHI nodes in E_OUT->DEST. */
4088 redirect_eh_edge_1 (e_in, e_out->dest, false);
4089 redirect_edge_pred (e_out, e_in->src);
4090 e_out->flags = e_in->flags;
4091 e_out->probability = e_in->probability;
4092 e_out->count = e_in->count;
4093 remove_edge (e_in);
4095 return true;
4098 /* Examine each landing pad block and see if it matches unsplit_eh. */
4100 static bool
4101 unsplit_all_eh (void)
4103 bool changed = false;
4104 eh_landing_pad lp;
4105 int i;
4107 for (i = 1; vec_safe_iterate (cfun->eh->lp_array, i, &lp); ++i)
4108 if (lp)
4109 changed |= unsplit_eh (lp);
4111 return changed;
4114 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
4115 to OLD_BB to NEW_BB; return true on success, false on failure.
4117 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
4118 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
4119 Virtual PHIs may be deleted and marked for renaming. */
4121 static bool
4122 cleanup_empty_eh_merge_phis (basic_block new_bb, basic_block old_bb,
4123 edge old_bb_out, bool change_region)
4125 gimple_stmt_iterator ngsi, ogsi;
4126 edge_iterator ei;
4127 edge e;
4128 bitmap ophi_handled;
4130 /* The destination block must not be a regular successor for any
4131 of the preds of the landing pad. Thus, avoid turning
4132 <..>
4133 | \ EH
4134 | <..>
4136 <..>
4137 into
4138 <..>
4139 | | EH
4140 <..>
4141 which CFG verification would choke on. See PR45172 and PR51089. */
4142 FOR_EACH_EDGE (e, ei, old_bb->preds)
4143 if (find_edge (e->src, new_bb))
4144 return false;
4146 FOR_EACH_EDGE (e, ei, old_bb->preds)
4147 redirect_edge_var_map_clear (e);
4149 ophi_handled = BITMAP_ALLOC (NULL);
4151 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
4152 for the edges we're going to move. */
4153 for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); gsi_next (&ngsi))
4155 gimple ophi, nphi = gsi_stmt (ngsi);
4156 tree nresult, nop;
4158 nresult = gimple_phi_result (nphi);
4159 nop = gimple_phi_arg_def (nphi, old_bb_out->dest_idx);
4161 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
4162 the source ssa_name. */
4163 ophi = NULL;
4164 for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
4166 ophi = gsi_stmt (ogsi);
4167 if (gimple_phi_result (ophi) == nop)
4168 break;
4169 ophi = NULL;
4172 /* If we did find the corresponding PHI, copy those inputs. */
4173 if (ophi)
4175 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
4176 if (!has_single_use (nop))
4178 imm_use_iterator imm_iter;
4179 use_operand_p use_p;
4181 FOR_EACH_IMM_USE_FAST (use_p, imm_iter, nop)
4183 if (!gimple_debug_bind_p (USE_STMT (use_p))
4184 && (gimple_code (USE_STMT (use_p)) != GIMPLE_PHI
4185 || gimple_bb (USE_STMT (use_p)) != new_bb))
4186 goto fail;
4189 bitmap_set_bit (ophi_handled, SSA_NAME_VERSION (nop));
4190 FOR_EACH_EDGE (e, ei, old_bb->preds)
4192 location_t oloc;
4193 tree oop;
4195 if ((e->flags & EDGE_EH) == 0)
4196 continue;
4197 oop = gimple_phi_arg_def (ophi, e->dest_idx);
4198 oloc = gimple_phi_arg_location (ophi, e->dest_idx);
4199 redirect_edge_var_map_add (e, nresult, oop, oloc);
4202 /* If we didn't find the PHI, if it's a real variable or a VOP, we know
4203 from the fact that OLD_BB is tree_empty_eh_handler_p that the
4204 variable is unchanged from input to the block and we can simply
4205 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
4206 else
4208 location_t nloc
4209 = gimple_phi_arg_location (nphi, old_bb_out->dest_idx);
4210 FOR_EACH_EDGE (e, ei, old_bb->preds)
4211 redirect_edge_var_map_add (e, nresult, nop, nloc);
4215 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
4216 we don't know what values from the other edges into NEW_BB to use. */
4217 for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
4219 gimple ophi = gsi_stmt (ogsi);
4220 tree oresult = gimple_phi_result (ophi);
4221 if (!bitmap_bit_p (ophi_handled, SSA_NAME_VERSION (oresult)))
4222 goto fail;
4225 /* Finally, move the edges and update the PHIs. */
4226 for (ei = ei_start (old_bb->preds); (e = ei_safe_edge (ei)); )
4227 if (e->flags & EDGE_EH)
4229 /* ??? CFG manipluation routines do not try to update loop
4230 form on edge redirection. Do so manually here for now. */
4231 /* If we redirect a loop entry or latch edge that will either create
4232 a multiple entry loop or rotate the loop. If the loops merge
4233 we may have created a loop with multiple latches.
4234 All of this isn't easily fixed thus cancel the affected loop
4235 and mark the other loop as possibly having multiple latches. */
4236 if (current_loops
4237 && e->dest == e->dest->loop_father->header)
4239 e->dest->loop_father->header = NULL;
4240 e->dest->loop_father->latch = NULL;
4241 new_bb->loop_father->latch = NULL;
4242 loops_state_set (LOOPS_NEED_FIXUP|LOOPS_MAY_HAVE_MULTIPLE_LATCHES);
4244 redirect_eh_edge_1 (e, new_bb, change_region);
4245 redirect_edge_succ (e, new_bb);
4246 flush_pending_stmts (e);
4248 else
4249 ei_next (&ei);
4251 BITMAP_FREE (ophi_handled);
4252 return true;
4254 fail:
4255 FOR_EACH_EDGE (e, ei, old_bb->preds)
4256 redirect_edge_var_map_clear (e);
4257 BITMAP_FREE (ophi_handled);
4258 return false;
4261 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
4262 old region to NEW_REGION at BB. */
4264 static void
4265 cleanup_empty_eh_move_lp (basic_block bb, edge e_out,
4266 eh_landing_pad lp, eh_region new_region)
4268 gimple_stmt_iterator gsi;
4269 eh_landing_pad *pp;
4271 for (pp = &lp->region->landing_pads; *pp != lp; pp = &(*pp)->next_lp)
4272 continue;
4273 *pp = lp->next_lp;
4275 lp->region = new_region;
4276 lp->next_lp = new_region->landing_pads;
4277 new_region->landing_pads = lp;
4279 /* Delete the RESX that was matched within the empty handler block. */
4280 gsi = gsi_last_bb (bb);
4281 unlink_stmt_vdef (gsi_stmt (gsi));
4282 gsi_remove (&gsi, true);
4284 /* Clean up E_OUT for the fallthru. */
4285 e_out->flags = (e_out->flags & ~EDGE_EH) | EDGE_FALLTHRU;
4286 e_out->probability = REG_BR_PROB_BASE;
4289 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
4290 unsplitting than unsplit_eh was prepared to handle, e.g. when
4291 multiple incoming edges and phis are involved. */
4293 static bool
4294 cleanup_empty_eh_unsplit (basic_block bb, edge e_out, eh_landing_pad lp)
4296 gimple_stmt_iterator gsi;
4297 tree lab;
4299 /* We really ought not have totally lost everything following
4300 a landing pad label. Given that BB is empty, there had better
4301 be a successor. */
4302 gcc_assert (e_out != NULL);
4304 /* The destination block must not already have a landing pad
4305 for a different region. */
4306 lab = NULL;
4307 for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
4309 gimple stmt = gsi_stmt (gsi);
4310 int lp_nr;
4312 if (gimple_code (stmt) != GIMPLE_LABEL)
4313 break;
4314 lab = gimple_label_label (stmt);
4315 lp_nr = EH_LANDING_PAD_NR (lab);
4316 if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
4317 return false;
4320 /* Attempt to move the PHIs into the successor block. */
4321 if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, false))
4323 if (dump_file && (dump_flags & TDF_DETAILS))
4324 fprintf (dump_file,
4325 "Unsplit EH landing pad %d to block %i "
4326 "(via cleanup_empty_eh).\n",
4327 lp->index, e_out->dest->index);
4328 return true;
4331 return false;
4334 /* Return true if edge E_FIRST is part of an empty infinite loop
4335 or leads to such a loop through a series of single successor
4336 empty bbs. */
4338 static bool
4339 infinite_empty_loop_p (edge e_first)
4341 bool inf_loop = false;
4342 edge e;
4344 if (e_first->dest == e_first->src)
4345 return true;
4347 e_first->src->aux = (void *) 1;
4348 for (e = e_first; single_succ_p (e->dest); e = single_succ_edge (e->dest))
4350 gimple_stmt_iterator gsi;
4351 if (e->dest->aux)
4353 inf_loop = true;
4354 break;
4356 e->dest->aux = (void *) 1;
4357 gsi = gsi_after_labels (e->dest);
4358 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
4359 gsi_next_nondebug (&gsi);
4360 if (!gsi_end_p (gsi))
4361 break;
4363 e_first->src->aux = NULL;
4364 for (e = e_first; e->dest->aux; e = single_succ_edge (e->dest))
4365 e->dest->aux = NULL;
4367 return inf_loop;
4370 /* Examine the block associated with LP to determine if it's an empty
4371 handler for its EH region. If so, attempt to redirect EH edges to
4372 an outer region. Return true the CFG was updated in any way. This
4373 is similar to jump forwarding, just across EH edges. */
4375 static bool
4376 cleanup_empty_eh (eh_landing_pad lp)
4378 basic_block bb = label_to_block (lp->post_landing_pad);
4379 gimple_stmt_iterator gsi;
4380 gimple resx;
4381 eh_region new_region;
4382 edge_iterator ei;
4383 edge e, e_out;
4384 bool has_non_eh_pred;
4385 bool ret = false;
4386 int new_lp_nr;
4388 /* There can be zero or one edges out of BB. This is the quickest test. */
4389 switch (EDGE_COUNT (bb->succs))
4391 case 0:
4392 e_out = NULL;
4393 break;
4394 case 1:
4395 e_out = single_succ_edge (bb);
4396 break;
4397 default:
4398 return false;
4401 resx = last_stmt (bb);
4402 if (resx && is_gimple_resx (resx))
4404 if (stmt_can_throw_external (resx))
4405 optimize_clobbers (bb);
4406 else if (sink_clobbers (bb))
4407 ret = true;
4410 gsi = gsi_after_labels (bb);
4412 /* Make sure to skip debug statements. */
4413 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
4414 gsi_next_nondebug (&gsi);
4416 /* If the block is totally empty, look for more unsplitting cases. */
4417 if (gsi_end_p (gsi))
4419 /* For the degenerate case of an infinite loop bail out.
4420 If bb has no successors and is totally empty, which can happen e.g.
4421 because of incorrect noreturn attribute, bail out too. */
4422 if (e_out == NULL
4423 || infinite_empty_loop_p (e_out))
4424 return ret;
4426 return ret | cleanup_empty_eh_unsplit (bb, e_out, lp);
4429 /* The block should consist only of a single RESX statement, modulo a
4430 preceding call to __builtin_stack_restore if there is no outgoing
4431 edge, since the call can be eliminated in this case. */
4432 resx = gsi_stmt (gsi);
4433 if (!e_out && gimple_call_builtin_p (resx, BUILT_IN_STACK_RESTORE))
4435 gsi_next (&gsi);
4436 resx = gsi_stmt (gsi);
4438 if (!is_gimple_resx (resx))
4439 return ret;
4440 gcc_assert (gsi_one_before_end_p (gsi));
4442 /* Determine if there are non-EH edges, or resx edges into the handler. */
4443 has_non_eh_pred = false;
4444 FOR_EACH_EDGE (e, ei, bb->preds)
4445 if (!(e->flags & EDGE_EH))
4446 has_non_eh_pred = true;
4448 /* Find the handler that's outer of the empty handler by looking at
4449 where the RESX instruction was vectored. */
4450 new_lp_nr = lookup_stmt_eh_lp (resx);
4451 new_region = get_eh_region_from_lp_number (new_lp_nr);
4453 /* If there's no destination region within the current function,
4454 redirection is trivial via removing the throwing statements from
4455 the EH region, removing the EH edges, and allowing the block
4456 to go unreachable. */
4457 if (new_region == NULL)
4459 gcc_assert (e_out == NULL);
4460 for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
4461 if (e->flags & EDGE_EH)
4463 gimple stmt = last_stmt (e->src);
4464 remove_stmt_from_eh_lp (stmt);
4465 remove_edge (e);
4467 else
4468 ei_next (&ei);
4469 goto succeed;
4472 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4473 to handle the abort and allow the blocks to go unreachable. */
4474 if (new_region->type == ERT_MUST_NOT_THROW)
4476 for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
4477 if (e->flags & EDGE_EH)
4479 gimple stmt = last_stmt (e->src);
4480 remove_stmt_from_eh_lp (stmt);
4481 add_stmt_to_eh_lp (stmt, new_lp_nr);
4482 remove_edge (e);
4484 else
4485 ei_next (&ei);
4486 goto succeed;
4489 /* Try to redirect the EH edges and merge the PHIs into the destination
4490 landing pad block. If the merge succeeds, we'll already have redirected
4491 all the EH edges. The handler itself will go unreachable if there were
4492 no normal edges. */
4493 if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, true))
4494 goto succeed;
4496 /* Finally, if all input edges are EH edges, then we can (potentially)
4497 reduce the number of transfers from the runtime by moving the landing
4498 pad from the original region to the new region. This is a win when
4499 we remove the last CLEANUP region along a particular exception
4500 propagation path. Since nothing changes except for the region with
4501 which the landing pad is associated, the PHI nodes do not need to be
4502 adjusted at all. */
4503 if (!has_non_eh_pred)
4505 cleanup_empty_eh_move_lp (bb, e_out, lp, new_region);
4506 if (dump_file && (dump_flags & TDF_DETAILS))
4507 fprintf (dump_file, "Empty EH handler %i moved to EH region %i.\n",
4508 lp->index, new_region->index);
4510 /* ??? The CFG didn't change, but we may have rendered the
4511 old EH region unreachable. Trigger a cleanup there. */
4512 return true;
4515 return ret;
4517 succeed:
4518 if (dump_file && (dump_flags & TDF_DETAILS))
4519 fprintf (dump_file, "Empty EH handler %i removed.\n", lp->index);
4520 remove_eh_landing_pad (lp);
4521 return true;
4524 /* Do a post-order traversal of the EH region tree. Examine each
4525 post_landing_pad block and see if we can eliminate it as empty. */
4527 static bool
4528 cleanup_all_empty_eh (void)
4530 bool changed = false;
4531 eh_landing_pad lp;
4532 int i;
4534 for (i = 1; vec_safe_iterate (cfun->eh->lp_array, i, &lp); ++i)
4535 if (lp)
4536 changed |= cleanup_empty_eh (lp);
4538 return changed;
4541 /* Perform cleanups and lowering of exception handling
4542 1) cleanups regions with handlers doing nothing are optimized out
4543 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4544 3) Info about regions that are containing instructions, and regions
4545 reachable via local EH edges is collected
4546 4) Eh tree is pruned for regions no longer necessary.
4548 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4549 Unify those that have the same failure decl and locus.
4552 static unsigned int
4553 execute_cleanup_eh_1 (void)
4555 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4556 looking up unreachable landing pads. */
4557 remove_unreachable_handlers ();
4559 /* Watch out for the region tree vanishing due to all unreachable. */
4560 if (cfun->eh->region_tree)
4562 bool changed = false;
4564 if (optimize)
4565 changed |= unsplit_all_eh ();
4566 changed |= cleanup_all_empty_eh ();
4568 if (changed)
4570 free_dominance_info (CDI_DOMINATORS);
4571 free_dominance_info (CDI_POST_DOMINATORS);
4573 /* We delayed all basic block deletion, as we may have performed
4574 cleanups on EH edges while non-EH edges were still present. */
4575 delete_unreachable_blocks ();
4577 /* We manipulated the landing pads. Remove any region that no
4578 longer has a landing pad. */
4579 remove_unreachable_handlers_no_lp ();
4581 return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals;
4585 return 0;
4588 static unsigned int
4589 execute_cleanup_eh (void)
4591 int ret = execute_cleanup_eh_1 ();
4593 /* If the function no longer needs an EH personality routine
4594 clear it. This exposes cross-language inlining opportunities
4595 and avoids references to a never defined personality routine. */
4596 if (DECL_FUNCTION_PERSONALITY (current_function_decl)
4597 && function_needs_eh_personality (cfun) != eh_personality_lang)
4598 DECL_FUNCTION_PERSONALITY (current_function_decl) = NULL_TREE;
4600 return ret;
4603 static bool
4604 gate_cleanup_eh (void)
4606 return cfun->eh != NULL && cfun->eh->region_tree != NULL;
4609 namespace {
4611 const pass_data pass_data_cleanup_eh =
4613 GIMPLE_PASS, /* type */
4614 "ehcleanup", /* name */
4615 OPTGROUP_NONE, /* optinfo_flags */
4616 true, /* has_gate */
4617 true, /* has_execute */
4618 TV_TREE_EH, /* tv_id */
4619 PROP_gimple_lcf, /* properties_required */
4620 0, /* properties_provided */
4621 0, /* properties_destroyed */
4622 0, /* todo_flags_start */
4623 TODO_verify_ssa, /* todo_flags_finish */
4626 class pass_cleanup_eh : public gimple_opt_pass
4628 public:
4629 pass_cleanup_eh (gcc::context *ctxt)
4630 : gimple_opt_pass (pass_data_cleanup_eh, ctxt)
4633 /* opt_pass methods: */
4634 opt_pass * clone () { return new pass_cleanup_eh (m_ctxt); }
4635 bool gate () { return gate_cleanup_eh (); }
4636 unsigned int execute () { return execute_cleanup_eh (); }
4638 }; // class pass_cleanup_eh
4640 } // anon namespace
4642 gimple_opt_pass *
4643 make_pass_cleanup_eh (gcc::context *ctxt)
4645 return new pass_cleanup_eh (ctxt);
4648 /* Verify that BB containing STMT as the last statement, has precisely the
4649 edge that make_eh_edges would create. */
4651 DEBUG_FUNCTION bool
4652 verify_eh_edges (gimple stmt)
4654 basic_block bb = gimple_bb (stmt);
4655 eh_landing_pad lp = NULL;
4656 int lp_nr;
4657 edge_iterator ei;
4658 edge e, eh_edge;
4660 lp_nr = lookup_stmt_eh_lp (stmt);
4661 if (lp_nr > 0)
4662 lp = get_eh_landing_pad_from_number (lp_nr);
4664 eh_edge = NULL;
4665 FOR_EACH_EDGE (e, ei, bb->succs)
4667 if (e->flags & EDGE_EH)
4669 if (eh_edge)
4671 error ("BB %i has multiple EH edges", bb->index);
4672 return true;
4674 else
4675 eh_edge = e;
4679 if (lp == NULL)
4681 if (eh_edge)
4683 error ("BB %i can not throw but has an EH edge", bb->index);
4684 return true;
4686 return false;
4689 if (!stmt_could_throw_p (stmt))
4691 error ("BB %i last statement has incorrectly set lp", bb->index);
4692 return true;
4695 if (eh_edge == NULL)
4697 error ("BB %i is missing an EH edge", bb->index);
4698 return true;
4701 if (eh_edge->dest != label_to_block (lp->post_landing_pad))
4703 error ("Incorrect EH edge %i->%i", bb->index, eh_edge->dest->index);
4704 return true;
4707 return false;
4710 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4712 DEBUG_FUNCTION bool
4713 verify_eh_dispatch_edge (gimple stmt)
4715 eh_region r;
4716 eh_catch c;
4717 basic_block src, dst;
4718 bool want_fallthru = true;
4719 edge_iterator ei;
4720 edge e, fall_edge;
4722 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
4723 src = gimple_bb (stmt);
4725 FOR_EACH_EDGE (e, ei, src->succs)
4726 gcc_assert (e->aux == NULL);
4728 switch (r->type)
4730 case ERT_TRY:
4731 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
4733 dst = label_to_block (c->label);
4734 e = find_edge (src, dst);
4735 if (e == NULL)
4737 error ("BB %i is missing an edge", src->index);
4738 return true;
4740 e->aux = (void *)e;
4742 /* A catch-all handler doesn't have a fallthru. */
4743 if (c->type_list == NULL)
4745 want_fallthru = false;
4746 break;
4749 break;
4751 case ERT_ALLOWED_EXCEPTIONS:
4752 dst = label_to_block (r->u.allowed.label);
4753 e = find_edge (src, dst);
4754 if (e == NULL)
4756 error ("BB %i is missing an edge", src->index);
4757 return true;
4759 e->aux = (void *)e;
4760 break;
4762 default:
4763 gcc_unreachable ();
4766 fall_edge = NULL;
4767 FOR_EACH_EDGE (e, ei, src->succs)
4769 if (e->flags & EDGE_FALLTHRU)
4771 if (fall_edge != NULL)
4773 error ("BB %i too many fallthru edges", src->index);
4774 return true;
4776 fall_edge = e;
4778 else if (e->aux)
4779 e->aux = NULL;
4780 else
4782 error ("BB %i has incorrect edge", src->index);
4783 return true;
4786 if ((fall_edge != NULL) ^ want_fallthru)
4788 error ("BB %i has incorrect fallthru edge", src->index);
4789 return true;
4792 return false;