1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
29 #include "pointer-set.h"
30 #include "tree-flow.h"
31 #include "tree-dump.h"
32 #include "tree-inline.h"
33 #include "tree-iterator.h"
34 #include "tree-pass.h"
36 #include "langhooks.h"
38 #include "diagnostic-core.h"
42 /* In some instances a tree and a gimple need to be stored in a same table,
43 i.e. in hash tables. This is a structure to do this. */
44 typedef union {tree *tp; tree t; gimple g;} treemple;
46 /* Nonzero if we are using EH to handle cleanups. */
47 static int using_eh_for_cleanups_p = 0;
50 using_eh_for_cleanups (void)
52 using_eh_for_cleanups_p = 1;
55 /* Misc functions used in this file. */
57 /* Remember and lookup EH landing pad data for arbitrary statements.
58 Really this means any statement that could_throw_p. We could
59 stuff this information into the stmt_ann data structure, but:
61 (1) We absolutely rely on this information being kept until
62 we get to rtl. Once we're done with lowering here, if we lose
63 the information there's no way to recover it!
65 (2) There are many more statements that *cannot* throw as
66 compared to those that can. We should be saving some amount
67 of space by only allocating memory for those that can throw. */
69 /* Add statement T in function IFUN to landing pad NUM. */
72 add_stmt_to_eh_lp_fn (struct function *ifun, gimple t, int num)
74 struct throw_stmt_node *n;
77 gcc_assert (num != 0);
79 n = ggc_alloc_throw_stmt_node ();
83 if (!get_eh_throw_stmt_table (ifun))
84 set_eh_throw_stmt_table (ifun, htab_create_ggc (31, struct_ptr_hash,
88 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), n, INSERT);
93 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
96 add_stmt_to_eh_lp (gimple t, int num)
98 add_stmt_to_eh_lp_fn (cfun, t, num);
101 /* Add statement T to the single EH landing pad in REGION. */
104 record_stmt_eh_region (eh_region region, gimple t)
108 if (region->type == ERT_MUST_NOT_THROW)
109 add_stmt_to_eh_lp_fn (cfun, t, -region->index);
112 eh_landing_pad lp = region->landing_pads;
114 lp = gen_eh_landing_pad (region);
116 gcc_assert (lp->next_lp == NULL);
117 add_stmt_to_eh_lp_fn (cfun, t, lp->index);
122 /* Remove statement T in function IFUN from its EH landing pad. */
125 remove_stmt_from_eh_lp_fn (struct function *ifun, gimple t)
127 struct throw_stmt_node dummy;
130 if (!get_eh_throw_stmt_table (ifun))
134 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), &dummy,
138 htab_clear_slot (get_eh_throw_stmt_table (ifun), slot);
146 /* Remove statement T in the current function (cfun) from its
150 remove_stmt_from_eh_lp (gimple t)
152 return remove_stmt_from_eh_lp_fn (cfun, t);
155 /* Determine if statement T is inside an EH region in function IFUN.
156 Positive numbers indicate a landing pad index; negative numbers
157 indicate a MUST_NOT_THROW region index; zero indicates that the
158 statement is not recorded in the region table. */
161 lookup_stmt_eh_lp_fn (struct function *ifun, gimple t)
163 struct throw_stmt_node *p, n;
165 if (ifun->eh->throw_stmt_table == NULL)
169 p = (struct throw_stmt_node *) htab_find (ifun->eh->throw_stmt_table, &n);
170 return p ? p->lp_nr : 0;
173 /* Likewise, but always use the current function. */
176 lookup_stmt_eh_lp (gimple t)
178 /* We can get called from initialized data when -fnon-call-exceptions
179 is on; prevent crash. */
182 return lookup_stmt_eh_lp_fn (cfun, t);
185 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
186 nodes and LABEL_DECL nodes. We will use this during the second phase to
187 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
189 struct finally_tree_node
191 /* When storing a GIMPLE_TRY, we have to record a gimple. However
192 when deciding whether a GOTO to a certain LABEL_DECL (which is a
193 tree) leaves the TRY block, its necessary to record a tree in
194 this field. Thus a treemple is used. */
199 /* Note that this table is *not* marked GTY. It is short-lived. */
200 static htab_t finally_tree;
203 record_in_finally_tree (treemple child, gimple parent)
205 struct finally_tree_node *n;
208 n = XNEW (struct finally_tree_node);
212 slot = htab_find_slot (finally_tree, n, INSERT);
218 collect_finally_tree (gimple stmt, gimple region);
220 /* Go through the gimple sequence. Works with collect_finally_tree to
221 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
224 collect_finally_tree_1 (gimple_seq seq, gimple region)
226 gimple_stmt_iterator gsi;
228 for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi))
229 collect_finally_tree (gsi_stmt (gsi), region);
233 collect_finally_tree (gimple stmt, gimple region)
237 switch (gimple_code (stmt))
240 temp.t = gimple_label_label (stmt);
241 record_in_finally_tree (temp, region);
245 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
248 record_in_finally_tree (temp, region);
249 collect_finally_tree_1 (gimple_try_eval (stmt), stmt);
250 collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
252 else if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH)
254 collect_finally_tree_1 (gimple_try_eval (stmt), region);
255 collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
260 collect_finally_tree_1 (gimple_catch_handler (stmt), region);
263 case GIMPLE_EH_FILTER:
264 collect_finally_tree_1 (gimple_eh_filter_failure (stmt), region);
268 collect_finally_tree_1 (gimple_eh_else_n_body (stmt), region);
269 collect_finally_tree_1 (gimple_eh_else_e_body (stmt), region);
273 /* A type, a decl, or some kind of statement that we're not
274 interested in. Don't walk them. */
280 /* Use the finally tree to determine if a jump from START to TARGET
281 would leave the try_finally node that START lives in. */
284 outside_finally_tree (treemple start, gimple target)
286 struct finally_tree_node n, *p;
291 p = (struct finally_tree_node *) htab_find (finally_tree, &n);
296 while (start.g != target);
301 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
302 nodes into a set of gotos, magic labels, and eh regions.
303 The eh region creation is straight-forward, but frobbing all the gotos
304 and such into shape isn't. */
306 /* The sequence into which we record all EH stuff. This will be
307 placed at the end of the function when we're all done. */
308 static gimple_seq eh_seq;
310 /* Record whether an EH region contains something that can throw,
311 indexed by EH region number. */
312 static bitmap eh_region_may_contain_throw_map;
314 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
315 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
316 The idea is to record a gimple statement for everything except for
317 the conditionals, which get their labels recorded. Since labels are
318 of type 'tree', we need this node to store both gimple and tree
319 objects. REPL_STMT is the sequence used to replace the goto/return
320 statement. CONT_STMT is used to store the statement that allows
321 the return/goto to jump to the original destination. */
323 struct goto_queue_node
326 gimple_seq repl_stmt;
329 /* This is used when index >= 0 to indicate that stmt is a label (as
330 opposed to a goto stmt). */
334 /* State of the world while lowering. */
338 /* What's "current" while constructing the eh region tree. These
339 correspond to variables of the same name in cfun->eh, which we
340 don't have easy access to. */
341 eh_region cur_region;
343 /* What's "current" for the purposes of __builtin_eh_pointer. For
344 a CATCH, this is the associated TRY. For an EH_FILTER, this is
345 the associated ALLOWED_EXCEPTIONS, etc. */
346 eh_region ehp_region;
348 /* Processing of TRY_FINALLY requires a bit more state. This is
349 split out into a separate structure so that we don't have to
350 copy so much when processing other nodes. */
351 struct leh_tf_state *tf;
356 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
357 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
358 this so that outside_finally_tree can reliably reference the tree used
359 in the collect_finally_tree data structures. */
360 gimple try_finally_expr;
363 /* While lowering a top_p usually it is expanded into multiple statements,
364 thus we need the following field to store them. */
365 gimple_seq top_p_seq;
367 /* The state outside this try_finally node. */
368 struct leh_state *outer;
370 /* The exception region created for it. */
373 /* The goto queue. */
374 struct goto_queue_node *goto_queue;
375 size_t goto_queue_size;
376 size_t goto_queue_active;
378 /* Pointer map to help in searching goto_queue when it is large. */
379 struct pointer_map_t *goto_queue_map;
381 /* The set of unique labels seen as entries in the goto queue. */
382 VEC(tree,heap) *dest_array;
384 /* A label to be added at the end of the completed transformed
385 sequence. It will be set if may_fallthru was true *at one time*,
386 though subsequent transformations may have cleared that flag. */
389 /* True if it is possible to fall out the bottom of the try block.
390 Cleared if the fallthru is converted to a goto. */
393 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
396 /* True if the finally block can receive an exception edge.
397 Cleared if the exception case is handled by code duplication. */
401 static gimple_seq lower_eh_must_not_throw (struct leh_state *, gimple);
403 /* Search for STMT in the goto queue. Return the replacement,
404 or null if the statement isn't in the queue. */
406 #define LARGE_GOTO_QUEUE 20
408 static void lower_eh_constructs_1 (struct leh_state *state, gimple_seq seq);
411 find_goto_replacement (struct leh_tf_state *tf, treemple stmt)
416 if (tf->goto_queue_active < LARGE_GOTO_QUEUE)
418 for (i = 0; i < tf->goto_queue_active; i++)
419 if ( tf->goto_queue[i].stmt.g == stmt.g)
420 return tf->goto_queue[i].repl_stmt;
424 /* If we have a large number of entries in the goto_queue, create a
425 pointer map and use that for searching. */
427 if (!tf->goto_queue_map)
429 tf->goto_queue_map = pointer_map_create ();
430 for (i = 0; i < tf->goto_queue_active; i++)
432 slot = pointer_map_insert (tf->goto_queue_map,
433 tf->goto_queue[i].stmt.g);
434 gcc_assert (*slot == NULL);
435 *slot = &tf->goto_queue[i];
439 slot = pointer_map_contains (tf->goto_queue_map, stmt.g);
441 return (((struct goto_queue_node *) *slot)->repl_stmt);
446 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
447 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
448 then we can just splat it in, otherwise we add the new stmts immediately
449 after the GIMPLE_COND and redirect. */
452 replace_goto_queue_cond_clause (tree *tp, struct leh_tf_state *tf,
453 gimple_stmt_iterator *gsi)
458 location_t loc = gimple_location (gsi_stmt (*gsi));
461 new_seq = find_goto_replacement (tf, temp);
465 if (gimple_seq_singleton_p (new_seq)
466 && gimple_code (gimple_seq_first_stmt (new_seq)) == GIMPLE_GOTO)
468 *tp = gimple_goto_dest (gimple_seq_first_stmt (new_seq));
472 label = create_artificial_label (loc);
473 /* Set the new label for the GIMPLE_COND */
476 gsi_insert_after (gsi, gimple_build_label (label), GSI_CONTINUE_LINKING);
477 gsi_insert_seq_after (gsi, gimple_seq_copy (new_seq), GSI_CONTINUE_LINKING);
480 /* The real work of replace_goto_queue. Returns with TSI updated to
481 point to the next statement. */
483 static void replace_goto_queue_stmt_list (gimple_seq, struct leh_tf_state *);
486 replace_goto_queue_1 (gimple stmt, struct leh_tf_state *tf,
487 gimple_stmt_iterator *gsi)
493 switch (gimple_code (stmt))
498 seq = find_goto_replacement (tf, temp);
501 gsi_insert_seq_before (gsi, gimple_seq_copy (seq), GSI_SAME_STMT);
502 gsi_remove (gsi, false);
508 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 2), tf, gsi);
509 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 3), tf, gsi);
513 replace_goto_queue_stmt_list (gimple_try_eval (stmt), tf);
514 replace_goto_queue_stmt_list (gimple_try_cleanup (stmt), tf);
517 replace_goto_queue_stmt_list (gimple_catch_handler (stmt), tf);
519 case GIMPLE_EH_FILTER:
520 replace_goto_queue_stmt_list (gimple_eh_filter_failure (stmt), tf);
523 replace_goto_queue_stmt_list (gimple_eh_else_n_body (stmt), tf);
524 replace_goto_queue_stmt_list (gimple_eh_else_e_body (stmt), tf);
528 /* These won't have gotos in them. */
535 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
538 replace_goto_queue_stmt_list (gimple_seq seq, struct leh_tf_state *tf)
540 gimple_stmt_iterator gsi = gsi_start (seq);
542 while (!gsi_end_p (gsi))
543 replace_goto_queue_1 (gsi_stmt (gsi), tf, &gsi);
546 /* Replace all goto queue members. */
549 replace_goto_queue (struct leh_tf_state *tf)
551 if (tf->goto_queue_active == 0)
553 replace_goto_queue_stmt_list (tf->top_p_seq, tf);
554 replace_goto_queue_stmt_list (eh_seq, tf);
557 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
558 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
562 record_in_goto_queue (struct leh_tf_state *tf,
568 struct goto_queue_node *q;
570 gcc_assert (!tf->goto_queue_map);
572 active = tf->goto_queue_active;
573 size = tf->goto_queue_size;
576 size = (size ? size * 2 : 32);
577 tf->goto_queue_size = size;
579 = XRESIZEVEC (struct goto_queue_node, tf->goto_queue, size);
582 q = &tf->goto_queue[active];
583 tf->goto_queue_active = active + 1;
585 memset (q, 0, sizeof (*q));
588 q->is_label = is_label;
591 /* Record the LABEL label in the goto queue contained in TF.
595 record_in_goto_queue_label (struct leh_tf_state *tf, treemple stmt, tree label)
598 treemple temp, new_stmt;
603 /* Computed and non-local gotos do not get processed. Given
604 their nature we can neither tell whether we've escaped the
605 finally block nor redirect them if we knew. */
606 if (TREE_CODE (label) != LABEL_DECL)
609 /* No need to record gotos that don't leave the try block. */
611 if (!outside_finally_tree (temp, tf->try_finally_expr))
614 if (! tf->dest_array)
616 tf->dest_array = VEC_alloc (tree, heap, 10);
617 VEC_quick_push (tree, tf->dest_array, label);
622 int n = VEC_length (tree, tf->dest_array);
623 for (index = 0; index < n; ++index)
624 if (VEC_index (tree, tf->dest_array, index) == label)
627 VEC_safe_push (tree, heap, tf->dest_array, label);
630 /* In the case of a GOTO we want to record the destination label,
631 since with a GIMPLE_COND we have an easy access to the then/else
634 record_in_goto_queue (tf, new_stmt, index, true);
637 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
638 node, and if so record that fact in the goto queue associated with that
642 maybe_record_in_goto_queue (struct leh_state *state, gimple stmt)
644 struct leh_tf_state *tf = state->tf;
650 switch (gimple_code (stmt))
653 new_stmt.tp = gimple_op_ptr (stmt, 2);
654 record_in_goto_queue_label (tf, new_stmt, gimple_cond_true_label (stmt));
655 new_stmt.tp = gimple_op_ptr (stmt, 3);
656 record_in_goto_queue_label (tf, new_stmt, gimple_cond_false_label (stmt));
660 record_in_goto_queue_label (tf, new_stmt, gimple_goto_dest (stmt));
664 tf->may_return = true;
666 record_in_goto_queue (tf, new_stmt, -1, false);
675 #ifdef ENABLE_CHECKING
676 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
677 was in fact structured, and we've not yet done jump threading, then none
678 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
681 verify_norecord_switch_expr (struct leh_state *state, gimple switch_expr)
683 struct leh_tf_state *tf = state->tf;
689 n = gimple_switch_num_labels (switch_expr);
691 for (i = 0; i < n; ++i)
694 tree lab = CASE_LABEL (gimple_switch_label (switch_expr, i));
696 gcc_assert (!outside_finally_tree (temp, tf->try_finally_expr));
700 #define verify_norecord_switch_expr(state, switch_expr)
703 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
704 non-null, insert it before the new branch. */
707 do_return_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod)
711 /* In the case of a return, the queue node must be a gimple statement. */
712 gcc_assert (!q->is_label);
714 /* Note that the return value may have already been computed, e.g.,
727 should return 0, not 1. We don't have to do anything to make
728 this happens because the return value has been placed in the
729 RESULT_DECL already. */
731 q->cont_stmt = q->stmt.g;
734 q->repl_stmt = gimple_seq_alloc ();
737 gimple_seq_add_seq (&q->repl_stmt, mod);
739 x = gimple_build_goto (finlab);
740 gimple_seq_add_stmt (&q->repl_stmt, x);
743 /* Similar, but easier, for GIMPLE_GOTO. */
746 do_goto_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod,
747 struct leh_tf_state *tf)
751 gcc_assert (q->is_label);
753 q->repl_stmt = gimple_seq_alloc ();
755 q->cont_stmt = gimple_build_goto (VEC_index (tree, tf->dest_array, q->index));
758 gimple_seq_add_seq (&q->repl_stmt, mod);
760 x = gimple_build_goto (finlab);
761 gimple_seq_add_stmt (&q->repl_stmt, x);
764 /* Emit a standard landing pad sequence into SEQ for REGION. */
767 emit_post_landing_pad (gimple_seq *seq, eh_region region)
769 eh_landing_pad lp = region->landing_pads;
773 lp = gen_eh_landing_pad (region);
775 lp->post_landing_pad = create_artificial_label (UNKNOWN_LOCATION);
776 EH_LANDING_PAD_NR (lp->post_landing_pad) = lp->index;
778 x = gimple_build_label (lp->post_landing_pad);
779 gimple_seq_add_stmt (seq, x);
782 /* Emit a RESX statement into SEQ for REGION. */
785 emit_resx (gimple_seq *seq, eh_region region)
787 gimple x = gimple_build_resx (region->index);
788 gimple_seq_add_stmt (seq, x);
790 record_stmt_eh_region (region->outer, x);
793 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
796 emit_eh_dispatch (gimple_seq *seq, eh_region region)
798 gimple x = gimple_build_eh_dispatch (region->index);
799 gimple_seq_add_stmt (seq, x);
802 /* Note that the current EH region may contain a throw, or a
803 call to a function which itself may contain a throw. */
806 note_eh_region_may_contain_throw (eh_region region)
808 while (bitmap_set_bit (eh_region_may_contain_throw_map, region->index))
810 if (region->type == ERT_MUST_NOT_THROW)
812 region = region->outer;
818 /* Check if REGION has been marked as containing a throw. If REGION is
819 NULL, this predicate is false. */
822 eh_region_may_contain_throw (eh_region r)
824 return r && bitmap_bit_p (eh_region_may_contain_throw_map, r->index);
827 /* We want to transform
828 try { body; } catch { stuff; }
838 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
839 should be placed before the second operand, or NULL. OVER is
840 an existing label that should be put at the exit, or NULL. */
843 frob_into_branch_around (gimple tp, eh_region region, tree over)
846 gimple_seq cleanup, result;
847 location_t loc = gimple_location (tp);
849 cleanup = gimple_try_cleanup (tp);
850 result = gimple_try_eval (tp);
853 emit_post_landing_pad (&eh_seq, region);
855 if (gimple_seq_may_fallthru (cleanup))
858 over = create_artificial_label (loc);
859 x = gimple_build_goto (over);
860 gimple_seq_add_stmt (&cleanup, x);
862 gimple_seq_add_seq (&eh_seq, cleanup);
866 x = gimple_build_label (over);
867 gimple_seq_add_stmt (&result, x);
872 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
873 Make sure to record all new labels found. */
876 lower_try_finally_dup_block (gimple_seq seq, struct leh_state *outer_state)
878 gimple region = NULL;
881 new_seq = copy_gimple_seq_and_replace_locals (seq);
884 region = outer_state->tf->try_finally_expr;
885 collect_finally_tree_1 (new_seq, region);
890 /* A subroutine of lower_try_finally. Create a fallthru label for
891 the given try_finally state. The only tricky bit here is that
892 we have to make sure to record the label in our outer context. */
895 lower_try_finally_fallthru_label (struct leh_tf_state *tf)
897 tree label = tf->fallthru_label;
902 label = create_artificial_label (gimple_location (tf->try_finally_expr));
903 tf->fallthru_label = label;
907 record_in_finally_tree (temp, tf->outer->tf->try_finally_expr);
913 /* A subroutine of lower_try_finally. If FINALLY consits of a
914 GIMPLE_EH_ELSE node, return it. */
917 get_eh_else (gimple_seq finally)
919 gimple x = gimple_seq_first_stmt (finally);
920 if (gimple_code (x) == GIMPLE_EH_ELSE)
922 gcc_assert (gimple_seq_singleton_p (finally));
928 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
929 langhook returns non-null, then the language requires that the exception
930 path out of a try_finally be treated specially. To wit: the code within
931 the finally block may not itself throw an exception. We have two choices
932 here. First we can duplicate the finally block and wrap it in a
933 must_not_throw region. Second, we can generate code like
938 if (fintmp == eh_edge)
939 protect_cleanup_actions;
942 where "fintmp" is the temporary used in the switch statement generation
943 alternative considered below. For the nonce, we always choose the first
946 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
949 honor_protect_cleanup_actions (struct leh_state *outer_state,
950 struct leh_state *this_state,
951 struct leh_tf_state *tf)
953 tree protect_cleanup_actions;
954 gimple_stmt_iterator gsi;
955 bool finally_may_fallthru;
959 /* First check for nothing to do. */
960 if (lang_hooks.eh_protect_cleanup_actions == NULL)
962 protect_cleanup_actions = lang_hooks.eh_protect_cleanup_actions ();
963 if (protect_cleanup_actions == NULL)
966 finally = gimple_try_cleanup (tf->top_p);
967 eh_else = get_eh_else (finally);
969 /* Duplicate the FINALLY block. Only need to do this for try-finally,
970 and not for cleanups. If we've got an EH_ELSE, extract it now. */
973 finally = gimple_eh_else_e_body (eh_else);
974 gimple_try_set_cleanup (tf->top_p, gimple_eh_else_n_body (eh_else));
977 finally = lower_try_finally_dup_block (finally, outer_state);
978 finally_may_fallthru = gimple_seq_may_fallthru (finally);
980 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
981 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
982 to be in an enclosing scope, but needs to be implemented at this level
983 to avoid a nesting violation (see wrap_temporary_cleanups in
984 cp/decl.c). Since it's logically at an outer level, we should call
985 terminate before we get to it, so strip it away before adding the
986 MUST_NOT_THROW filter. */
987 gsi = gsi_start (finally);
989 if (gimple_code (x) == GIMPLE_TRY
990 && gimple_try_kind (x) == GIMPLE_TRY_CATCH
991 && gimple_try_catch_is_cleanup (x))
993 gsi_insert_seq_before (&gsi, gimple_try_eval (x), GSI_SAME_STMT);
994 gsi_remove (&gsi, false);
997 /* Wrap the block with protect_cleanup_actions as the action. */
998 x = gimple_build_eh_must_not_throw (protect_cleanup_actions);
999 x = gimple_build_try (finally, gimple_seq_alloc_with_stmt (x),
1001 finally = lower_eh_must_not_throw (outer_state, x);
1003 /* Drop all of this into the exception sequence. */
1004 emit_post_landing_pad (&eh_seq, tf->region);
1005 gimple_seq_add_seq (&eh_seq, finally);
1006 if (finally_may_fallthru)
1007 emit_resx (&eh_seq, tf->region);
1009 /* Having now been handled, EH isn't to be considered with
1010 the rest of the outgoing edges. */
1011 tf->may_throw = false;
1014 /* A subroutine of lower_try_finally. We have determined that there is
1015 no fallthru edge out of the finally block. This means that there is
1016 no outgoing edge corresponding to any incoming edge. Restructure the
1017 try_finally node for this special case. */
1020 lower_try_finally_nofallthru (struct leh_state *state,
1021 struct leh_tf_state *tf)
1026 struct goto_queue_node *q, *qe;
1028 lab = create_artificial_label (gimple_location (tf->try_finally_expr));
1030 /* We expect that tf->top_p is a GIMPLE_TRY. */
1031 finally = gimple_try_cleanup (tf->top_p);
1032 tf->top_p_seq = gimple_try_eval (tf->top_p);
1034 x = gimple_build_label (lab);
1035 gimple_seq_add_stmt (&tf->top_p_seq, x);
1038 qe = q + tf->goto_queue_active;
1041 do_return_redirection (q, lab, NULL);
1043 do_goto_redirection (q, lab, NULL, tf);
1045 replace_goto_queue (tf);
1047 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1048 eh_else = get_eh_else (finally);
1051 finally = gimple_eh_else_n_body (eh_else);
1052 lower_eh_constructs_1 (state, finally);
1053 gimple_seq_add_seq (&tf->top_p_seq, finally);
1057 finally = gimple_eh_else_e_body (eh_else);
1058 lower_eh_constructs_1 (state, finally);
1060 emit_post_landing_pad (&eh_seq, tf->region);
1061 gimple_seq_add_seq (&eh_seq, finally);
1066 lower_eh_constructs_1 (state, finally);
1067 gimple_seq_add_seq (&tf->top_p_seq, finally);
1071 emit_post_landing_pad (&eh_seq, tf->region);
1073 x = gimple_build_goto (lab);
1074 gimple_seq_add_stmt (&eh_seq, x);
1079 /* A subroutine of lower_try_finally. We have determined that there is
1080 exactly one destination of the finally block. Restructure the
1081 try_finally node for this special case. */
1084 lower_try_finally_onedest (struct leh_state *state, struct leh_tf_state *tf)
1086 struct goto_queue_node *q, *qe;
1090 location_t loc = gimple_location (tf->try_finally_expr);
1092 finally = gimple_try_cleanup (tf->top_p);
1093 tf->top_p_seq = gimple_try_eval (tf->top_p);
1095 /* Since there's only one destination, and the destination edge can only
1096 either be EH or non-EH, that implies that all of our incoming edges
1097 are of the same type. Therefore we can lower EH_ELSE immediately. */
1098 x = get_eh_else (finally);
1102 finally = gimple_eh_else_e_body (x);
1104 finally = gimple_eh_else_n_body (x);
1107 lower_eh_constructs_1 (state, finally);
1111 /* Only reachable via the exception edge. Add the given label to
1112 the head of the FINALLY block. Append a RESX at the end. */
1113 emit_post_landing_pad (&eh_seq, tf->region);
1114 gimple_seq_add_seq (&eh_seq, finally);
1115 emit_resx (&eh_seq, tf->region);
1119 if (tf->may_fallthru)
1121 /* Only reachable via the fallthru edge. Do nothing but let
1122 the two blocks run together; we'll fall out the bottom. */
1123 gimple_seq_add_seq (&tf->top_p_seq, finally);
1127 finally_label = create_artificial_label (loc);
1128 x = gimple_build_label (finally_label);
1129 gimple_seq_add_stmt (&tf->top_p_seq, x);
1131 gimple_seq_add_seq (&tf->top_p_seq, finally);
1134 qe = q + tf->goto_queue_active;
1138 /* Reachable by return expressions only. Redirect them. */
1140 do_return_redirection (q, finally_label, NULL);
1141 replace_goto_queue (tf);
1145 /* Reachable by goto expressions only. Redirect them. */
1147 do_goto_redirection (q, finally_label, NULL, tf);
1148 replace_goto_queue (tf);
1150 if (VEC_index (tree, tf->dest_array, 0) == tf->fallthru_label)
1152 /* Reachable by goto to fallthru label only. Redirect it
1153 to the new label (already created, sadly), and do not
1154 emit the final branch out, or the fallthru label. */
1155 tf->fallthru_label = NULL;
1160 /* Place the original return/goto to the original destination
1161 immediately after the finally block. */
1162 x = tf->goto_queue[0].cont_stmt;
1163 gimple_seq_add_stmt (&tf->top_p_seq, x);
1164 maybe_record_in_goto_queue (state, x);
1167 /* A subroutine of lower_try_finally. There are multiple edges incoming
1168 and outgoing from the finally block. Implement this by duplicating the
1169 finally block for every destination. */
1172 lower_try_finally_copy (struct leh_state *state, struct leh_tf_state *tf)
1175 gimple_seq new_stmt;
1179 location_t tf_loc = gimple_location (tf->try_finally_expr);
1181 finally = gimple_try_cleanup (tf->top_p);
1183 /* Notice EH_ELSE, and simplify some of the remaining code
1184 by considering FINALLY to be the normal return path only. */
1185 eh_else = get_eh_else (finally);
1187 finally = gimple_eh_else_n_body (eh_else);
1189 tf->top_p_seq = gimple_try_eval (tf->top_p);
1192 if (tf->may_fallthru)
1194 seq = lower_try_finally_dup_block (finally, state);
1195 lower_eh_constructs_1 (state, seq);
1196 gimple_seq_add_seq (&new_stmt, seq);
1198 tmp = lower_try_finally_fallthru_label (tf);
1199 x = gimple_build_goto (tmp);
1200 gimple_seq_add_stmt (&new_stmt, x);
1205 /* We don't need to copy the EH path of EH_ELSE,
1206 since it is only emitted once. */
1208 seq = gimple_eh_else_e_body (eh_else);
1210 seq = lower_try_finally_dup_block (finally, state);
1211 lower_eh_constructs_1 (state, seq);
1213 emit_post_landing_pad (&eh_seq, tf->region);
1214 gimple_seq_add_seq (&eh_seq, seq);
1215 emit_resx (&eh_seq, tf->region);
1220 struct goto_queue_node *q, *qe;
1221 int return_index, index;
1224 struct goto_queue_node *q;
1228 return_index = VEC_length (tree, tf->dest_array);
1229 labels = XCNEWVEC (struct labels_s, return_index + 1);
1232 qe = q + tf->goto_queue_active;
1235 index = q->index < 0 ? return_index : q->index;
1237 if (!labels[index].q)
1238 labels[index].q = q;
1241 for (index = 0; index < return_index + 1; index++)
1245 q = labels[index].q;
1249 lab = labels[index].label
1250 = create_artificial_label (tf_loc);
1252 if (index == return_index)
1253 do_return_redirection (q, lab, NULL);
1255 do_goto_redirection (q, lab, NULL, tf);
1257 x = gimple_build_label (lab);
1258 gimple_seq_add_stmt (&new_stmt, x);
1260 seq = lower_try_finally_dup_block (finally, state);
1261 lower_eh_constructs_1 (state, seq);
1262 gimple_seq_add_seq (&new_stmt, seq);
1264 gimple_seq_add_stmt (&new_stmt, q->cont_stmt);
1265 maybe_record_in_goto_queue (state, q->cont_stmt);
1268 for (q = tf->goto_queue; q < qe; q++)
1272 index = q->index < 0 ? return_index : q->index;
1274 if (labels[index].q == q)
1277 lab = labels[index].label;
1279 if (index == return_index)
1280 do_return_redirection (q, lab, NULL);
1282 do_goto_redirection (q, lab, NULL, tf);
1285 replace_goto_queue (tf);
1289 /* Need to link new stmts after running replace_goto_queue due
1290 to not wanting to process the same goto stmts twice. */
1291 gimple_seq_add_seq (&tf->top_p_seq, new_stmt);
1294 /* A subroutine of lower_try_finally. There are multiple edges incoming
1295 and outgoing from the finally block. Implement this by instrumenting
1296 each incoming edge and creating a switch statement at the end of the
1297 finally block that branches to the appropriate destination. */
1300 lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf)
1302 struct goto_queue_node *q, *qe;
1303 tree finally_tmp, finally_label;
1304 int return_index, eh_index, fallthru_index;
1305 int nlabels, ndests, j, last_case_index;
1307 VEC (tree,heap) *case_label_vec;
1308 gimple_seq switch_body;
1313 struct pointer_map_t *cont_map = NULL;
1314 /* The location of the TRY_FINALLY stmt. */
1315 location_t tf_loc = gimple_location (tf->try_finally_expr);
1316 /* The location of the finally block. */
1317 location_t finally_loc;
1319 switch_body = gimple_seq_alloc ();
1320 finally = gimple_try_cleanup (tf->top_p);
1321 eh_else = get_eh_else (finally);
1323 /* Mash the TRY block to the head of the chain. */
1324 tf->top_p_seq = gimple_try_eval (tf->top_p);
1326 /* The location of the finally is either the last stmt in the finally
1327 block or the location of the TRY_FINALLY itself. */
1328 x = gimple_seq_last_stmt (finally);
1329 finally_loc = x ? gimple_location (x) : tf_loc;
1331 /* Prepare for switch statement generation. */
1332 nlabels = VEC_length (tree, tf->dest_array);
1333 return_index = nlabels;
1334 eh_index = return_index + tf->may_return;
1335 fallthru_index = eh_index + (tf->may_throw && !eh_else);
1336 ndests = fallthru_index + tf->may_fallthru;
1338 finally_tmp = create_tmp_var (integer_type_node, "finally_tmp");
1339 finally_label = create_artificial_label (finally_loc);
1341 /* We use VEC_quick_push on case_label_vec throughout this function,
1342 since we know the size in advance and allocate precisely as muce
1344 case_label_vec = VEC_alloc (tree, heap, ndests);
1346 last_case_index = 0;
1348 /* Begin inserting code for getting to the finally block. Things
1349 are done in this order to correspond to the sequence the code is
1352 if (tf->may_fallthru)
1354 x = gimple_build_assign (finally_tmp,
1355 build_int_cst (integer_type_node,
1357 gimple_seq_add_stmt (&tf->top_p_seq, x);
1359 tmp = build_int_cst (integer_type_node, fallthru_index);
1360 last_case = build_case_label (tmp, NULL,
1361 create_artificial_label (tf_loc));
1362 VEC_quick_push (tree, case_label_vec, last_case);
1365 x = gimple_build_label (CASE_LABEL (last_case));
1366 gimple_seq_add_stmt (&switch_body, x);
1368 tmp = lower_try_finally_fallthru_label (tf);
1369 x = gimple_build_goto (tmp);
1370 gimple_seq_add_stmt (&switch_body, x);
1373 /* For EH_ELSE, emit the exception path (plus resx) now, then
1374 subsequently we only need consider the normal path. */
1379 finally = gimple_eh_else_e_body (eh_else);
1380 lower_eh_constructs_1 (state, finally);
1382 emit_post_landing_pad (&eh_seq, tf->region);
1383 gimple_seq_add_seq (&eh_seq, finally);
1384 emit_resx (&eh_seq, tf->region);
1387 finally = gimple_eh_else_n_body (eh_else);
1389 else if (tf->may_throw)
1391 emit_post_landing_pad (&eh_seq, tf->region);
1393 x = gimple_build_assign (finally_tmp,
1394 build_int_cst (integer_type_node, eh_index));
1395 gimple_seq_add_stmt (&eh_seq, x);
1397 x = gimple_build_goto (finally_label);
1398 gimple_seq_add_stmt (&eh_seq, x);
1400 tmp = build_int_cst (integer_type_node, eh_index);
1401 last_case = build_case_label (tmp, NULL,
1402 create_artificial_label (tf_loc));
1403 VEC_quick_push (tree, case_label_vec, last_case);
1406 x = gimple_build_label (CASE_LABEL (last_case));
1407 gimple_seq_add_stmt (&eh_seq, x);
1408 emit_resx (&eh_seq, tf->region);
1411 x = gimple_build_label (finally_label);
1412 gimple_seq_add_stmt (&tf->top_p_seq, x);
1414 lower_eh_constructs_1 (state, finally);
1415 gimple_seq_add_seq (&tf->top_p_seq, finally);
1417 /* Redirect each incoming goto edge. */
1419 qe = q + tf->goto_queue_active;
1420 j = last_case_index + tf->may_return;
1421 /* Prepare the assignments to finally_tmp that are executed upon the
1422 entrance through a particular edge. */
1427 unsigned int case_index;
1429 mod = gimple_seq_alloc ();
1433 x = gimple_build_assign (finally_tmp,
1434 build_int_cst (integer_type_node,
1436 gimple_seq_add_stmt (&mod, x);
1437 do_return_redirection (q, finally_label, mod);
1438 switch_id = return_index;
1442 x = gimple_build_assign (finally_tmp,
1443 build_int_cst (integer_type_node, q->index));
1444 gimple_seq_add_stmt (&mod, x);
1445 do_goto_redirection (q, finally_label, mod, tf);
1446 switch_id = q->index;
1449 case_index = j + q->index;
1450 if (VEC_length (tree, case_label_vec) <= case_index
1451 || !VEC_index (tree, case_label_vec, case_index))
1455 tmp = build_int_cst (integer_type_node, switch_id);
1456 case_lab = build_case_label (tmp, NULL,
1457 create_artificial_label (tf_loc));
1458 /* We store the cont_stmt in the pointer map, so that we can recover
1459 it in the loop below. */
1461 cont_map = pointer_map_create ();
1462 slot = pointer_map_insert (cont_map, case_lab);
1463 *slot = q->cont_stmt;
1464 VEC_quick_push (tree, case_label_vec, case_lab);
1467 for (j = last_case_index; j < last_case_index + nlabels; j++)
1472 last_case = VEC_index (tree, case_label_vec, j);
1474 gcc_assert (last_case);
1475 gcc_assert (cont_map);
1477 slot = pointer_map_contains (cont_map, last_case);
1479 cont_stmt = *(gimple *) slot;
1481 x = gimple_build_label (CASE_LABEL (last_case));
1482 gimple_seq_add_stmt (&switch_body, x);
1483 gimple_seq_add_stmt (&switch_body, cont_stmt);
1484 maybe_record_in_goto_queue (state, cont_stmt);
1487 pointer_map_destroy (cont_map);
1489 replace_goto_queue (tf);
1491 /* Make sure that the last case is the default label, as one is required.
1492 Then sort the labels, which is also required in GIMPLE. */
1493 CASE_LOW (last_case) = NULL;
1494 sort_case_labels (case_label_vec);
1496 /* Build the switch statement, setting last_case to be the default
1498 switch_stmt = gimple_build_switch_vec (finally_tmp, last_case,
1500 gimple_set_location (switch_stmt, finally_loc);
1502 /* Need to link SWITCH_STMT after running replace_goto_queue
1503 due to not wanting to process the same goto stmts twice. */
1504 gimple_seq_add_stmt (&tf->top_p_seq, switch_stmt);
1505 gimple_seq_add_seq (&tf->top_p_seq, switch_body);
1508 /* Decide whether or not we are going to duplicate the finally block.
1509 There are several considerations.
1511 First, if this is Java, then the finally block contains code
1512 written by the user. It has line numbers associated with it,
1513 so duplicating the block means it's difficult to set a breakpoint.
1514 Since controlling code generation via -g is verboten, we simply
1515 never duplicate code without optimization.
1517 Second, we'd like to prevent egregious code growth. One way to
1518 do this is to estimate the size of the finally block, multiply
1519 that by the number of copies we'd need to make, and compare against
1520 the estimate of the size of the switch machinery we'd have to add. */
1523 decide_copy_try_finally (int ndests, bool may_throw, gimple_seq finally)
1525 int f_estimate, sw_estimate;
1528 /* If there's an EH_ELSE involved, the exception path is separate
1529 and really doesn't come into play for this computation. */
1530 eh_else = get_eh_else (finally);
1533 ndests -= may_throw;
1534 finally = gimple_eh_else_n_body (eh_else);
1539 gimple_stmt_iterator gsi;
1544 for (gsi = gsi_start (finally); !gsi_end_p (gsi); gsi_next (&gsi))
1546 gimple stmt = gsi_stmt (gsi);
1547 if (!is_gimple_debug (stmt) && !gimple_clobber_p (stmt))
1553 /* Finally estimate N times, plus N gotos. */
1554 f_estimate = count_insns_seq (finally, &eni_size_weights);
1555 f_estimate = (f_estimate + 1) * ndests;
1557 /* Switch statement (cost 10), N variable assignments, N gotos. */
1558 sw_estimate = 10 + 2 * ndests;
1560 /* Optimize for size clearly wants our best guess. */
1561 if (optimize_function_for_size_p (cfun))
1562 return f_estimate < sw_estimate;
1564 /* ??? These numbers are completely made up so far. */
1566 return f_estimate < 100 || f_estimate < sw_estimate * 2;
1568 return f_estimate < 40 || f_estimate * 2 < sw_estimate * 3;
1571 /* REG is the enclosing region for a possible cleanup region, or the region
1572 itself. Returns TRUE if such a region would be unreachable.
1574 Cleanup regions within a must-not-throw region aren't actually reachable
1575 even if there are throwing stmts within them, because the personality
1576 routine will call terminate before unwinding. */
1579 cleanup_is_dead_in (eh_region reg)
1581 while (reg && reg->type == ERT_CLEANUP)
1583 return (reg && reg->type == ERT_MUST_NOT_THROW);
1586 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1587 to a sequence of labels and blocks, plus the exception region trees
1588 that record all the magic. This is complicated by the need to
1589 arrange for the FINALLY block to be executed on all exits. */
1592 lower_try_finally (struct leh_state *state, gimple tp)
1594 struct leh_tf_state this_tf;
1595 struct leh_state this_state;
1597 gimple_seq old_eh_seq;
1599 /* Process the try block. */
1601 memset (&this_tf, 0, sizeof (this_tf));
1602 this_tf.try_finally_expr = tp;
1604 this_tf.outer = state;
1605 if (using_eh_for_cleanups_p && !cleanup_is_dead_in (state->cur_region))
1607 this_tf.region = gen_eh_region_cleanup (state->cur_region);
1608 this_state.cur_region = this_tf.region;
1612 this_tf.region = NULL;
1613 this_state.cur_region = state->cur_region;
1616 this_state.ehp_region = state->ehp_region;
1617 this_state.tf = &this_tf;
1619 old_eh_seq = eh_seq;
1622 lower_eh_constructs_1 (&this_state, gimple_try_eval(tp));
1624 /* Determine if the try block is escaped through the bottom. */
1625 this_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
1627 /* Determine if any exceptions are possible within the try block. */
1629 this_tf.may_throw = eh_region_may_contain_throw (this_tf.region);
1630 if (this_tf.may_throw)
1631 honor_protect_cleanup_actions (state, &this_state, &this_tf);
1633 /* Determine how many edges (still) reach the finally block. Or rather,
1634 how many destinations are reached by the finally block. Use this to
1635 determine how we process the finally block itself. */
1637 ndests = VEC_length (tree, this_tf.dest_array);
1638 ndests += this_tf.may_fallthru;
1639 ndests += this_tf.may_return;
1640 ndests += this_tf.may_throw;
1642 /* If the FINALLY block is not reachable, dike it out. */
1645 gimple_seq_add_seq (&this_tf.top_p_seq, gimple_try_eval (tp));
1646 gimple_try_set_cleanup (tp, NULL);
1648 /* If the finally block doesn't fall through, then any destination
1649 we might try to impose there isn't reached either. There may be
1650 some minor amount of cleanup and redirection still needed. */
1651 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp)))
1652 lower_try_finally_nofallthru (state, &this_tf);
1654 /* We can easily special-case redirection to a single destination. */
1655 else if (ndests == 1)
1656 lower_try_finally_onedest (state, &this_tf);
1657 else if (decide_copy_try_finally (ndests, this_tf.may_throw,
1658 gimple_try_cleanup (tp)))
1659 lower_try_finally_copy (state, &this_tf);
1661 lower_try_finally_switch (state, &this_tf);
1663 /* If someone requested we add a label at the end of the transformed
1665 if (this_tf.fallthru_label)
1667 /* This must be reached only if ndests == 0. */
1668 gimple x = gimple_build_label (this_tf.fallthru_label);
1669 gimple_seq_add_stmt (&this_tf.top_p_seq, x);
1672 VEC_free (tree, heap, this_tf.dest_array);
1673 free (this_tf.goto_queue);
1674 if (this_tf.goto_queue_map)
1675 pointer_map_destroy (this_tf.goto_queue_map);
1677 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1678 If there was no old eh_seq, then the append is trivially already done. */
1682 eh_seq = old_eh_seq;
1685 gimple_seq new_eh_seq = eh_seq;
1686 eh_seq = old_eh_seq;
1687 gimple_seq_add_seq(&eh_seq, new_eh_seq);
1691 return this_tf.top_p_seq;
1694 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1695 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1696 exception region trees that records all the magic. */
1699 lower_catch (struct leh_state *state, gimple tp)
1701 eh_region try_region = NULL;
1702 struct leh_state this_state = *state;
1703 gimple_stmt_iterator gsi;
1707 location_t try_catch_loc = gimple_location (tp);
1709 if (flag_exceptions)
1711 try_region = gen_eh_region_try (state->cur_region);
1712 this_state.cur_region = try_region;
1715 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
1717 if (!eh_region_may_contain_throw (try_region))
1718 return gimple_try_eval (tp);
1721 emit_eh_dispatch (&new_seq, try_region);
1722 emit_resx (&new_seq, try_region);
1724 this_state.cur_region = state->cur_region;
1725 this_state.ehp_region = try_region;
1728 for (gsi = gsi_start (gimple_try_cleanup (tp));
1736 gcatch = gsi_stmt (gsi);
1737 c = gen_eh_region_catch (try_region, gimple_catch_types (gcatch));
1739 handler = gimple_catch_handler (gcatch);
1740 lower_eh_constructs_1 (&this_state, handler);
1742 c->label = create_artificial_label (UNKNOWN_LOCATION);
1743 x = gimple_build_label (c->label);
1744 gimple_seq_add_stmt (&new_seq, x);
1746 gimple_seq_add_seq (&new_seq, handler);
1748 if (gimple_seq_may_fallthru (new_seq))
1751 out_label = create_artificial_label (try_catch_loc);
1753 x = gimple_build_goto (out_label);
1754 gimple_seq_add_stmt (&new_seq, x);
1760 gimple_try_set_cleanup (tp, new_seq);
1762 return frob_into_branch_around (tp, try_region, out_label);
1765 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1766 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1767 region trees that record all the magic. */
1770 lower_eh_filter (struct leh_state *state, gimple tp)
1772 struct leh_state this_state = *state;
1773 eh_region this_region = NULL;
1777 inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
1779 if (flag_exceptions)
1781 this_region = gen_eh_region_allowed (state->cur_region,
1782 gimple_eh_filter_types (inner));
1783 this_state.cur_region = this_region;
1786 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
1788 if (!eh_region_may_contain_throw (this_region))
1789 return gimple_try_eval (tp);
1792 this_state.cur_region = state->cur_region;
1793 this_state.ehp_region = this_region;
1795 emit_eh_dispatch (&new_seq, this_region);
1796 emit_resx (&new_seq, this_region);
1798 this_region->u.allowed.label = create_artificial_label (UNKNOWN_LOCATION);
1799 x = gimple_build_label (this_region->u.allowed.label);
1800 gimple_seq_add_stmt (&new_seq, x);
1802 lower_eh_constructs_1 (&this_state, gimple_eh_filter_failure (inner));
1803 gimple_seq_add_seq (&new_seq, gimple_eh_filter_failure (inner));
1805 gimple_try_set_cleanup (tp, new_seq);
1807 return frob_into_branch_around (tp, this_region, NULL);
1810 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1811 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1812 plus the exception region trees that record all the magic. */
1815 lower_eh_must_not_throw (struct leh_state *state, gimple tp)
1817 struct leh_state this_state = *state;
1819 if (flag_exceptions)
1821 gimple inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
1822 eh_region this_region;
1824 this_region = gen_eh_region_must_not_throw (state->cur_region);
1825 this_region->u.must_not_throw.failure_decl
1826 = gimple_eh_must_not_throw_fndecl (inner);
1827 this_region->u.must_not_throw.failure_loc = gimple_location (tp);
1829 /* In order to get mangling applied to this decl, we must mark it
1830 used now. Otherwise, pass_ipa_free_lang_data won't think it
1832 TREE_USED (this_region->u.must_not_throw.failure_decl) = 1;
1834 this_state.cur_region = this_region;
1837 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
1839 return gimple_try_eval (tp);
1842 /* Implement a cleanup expression. This is similar to try-finally,
1843 except that we only execute the cleanup block for exception edges. */
1846 lower_cleanup (struct leh_state *state, gimple tp)
1848 struct leh_state this_state = *state;
1849 eh_region this_region = NULL;
1850 struct leh_tf_state fake_tf;
1852 bool cleanup_dead = cleanup_is_dead_in (state->cur_region);
1854 if (flag_exceptions && !cleanup_dead)
1856 this_region = gen_eh_region_cleanup (state->cur_region);
1857 this_state.cur_region = this_region;
1860 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
1862 if (cleanup_dead || !eh_region_may_contain_throw (this_region))
1863 return gimple_try_eval (tp);
1865 /* Build enough of a try-finally state so that we can reuse
1866 honor_protect_cleanup_actions. */
1867 memset (&fake_tf, 0, sizeof (fake_tf));
1868 fake_tf.top_p = fake_tf.try_finally_expr = tp;
1869 fake_tf.outer = state;
1870 fake_tf.region = this_region;
1871 fake_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
1872 fake_tf.may_throw = true;
1874 honor_protect_cleanup_actions (state, NULL, &fake_tf);
1876 if (fake_tf.may_throw)
1878 /* In this case honor_protect_cleanup_actions had nothing to do,
1879 and we should process this normally. */
1880 lower_eh_constructs_1 (state, gimple_try_cleanup (tp));
1881 result = frob_into_branch_around (tp, this_region,
1882 fake_tf.fallthru_label);
1886 /* In this case honor_protect_cleanup_actions did nearly all of
1887 the work. All we have left is to append the fallthru_label. */
1889 result = gimple_try_eval (tp);
1890 if (fake_tf.fallthru_label)
1892 gimple x = gimple_build_label (fake_tf.fallthru_label);
1893 gimple_seq_add_stmt (&result, x);
1899 /* Main loop for lowering eh constructs. Also moves gsi to the next
1903 lower_eh_constructs_2 (struct leh_state *state, gimple_stmt_iterator *gsi)
1907 gimple stmt = gsi_stmt (*gsi);
1909 switch (gimple_code (stmt))
1913 tree fndecl = gimple_call_fndecl (stmt);
1916 if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
1917 switch (DECL_FUNCTION_CODE (fndecl))
1919 case BUILT_IN_EH_POINTER:
1920 /* The front end may have generated a call to
1921 __builtin_eh_pointer (0) within a catch region. Replace
1922 this zero argument with the current catch region number. */
1923 if (state->ehp_region)
1925 tree nr = build_int_cst (integer_type_node,
1926 state->ehp_region->index);
1927 gimple_call_set_arg (stmt, 0, nr);
1931 /* The user has dome something silly. Remove it. */
1932 rhs = null_pointer_node;
1937 case BUILT_IN_EH_FILTER:
1938 /* ??? This should never appear, but since it's a builtin it
1939 is accessible to abuse by users. Just remove it and
1940 replace the use with the arbitrary value zero. */
1941 rhs = build_int_cst (TREE_TYPE (TREE_TYPE (fndecl)), 0);
1943 lhs = gimple_call_lhs (stmt);
1944 x = gimple_build_assign (lhs, rhs);
1945 gsi_insert_before (gsi, x, GSI_SAME_STMT);
1948 case BUILT_IN_EH_COPY_VALUES:
1949 /* Likewise this should not appear. Remove it. */
1950 gsi_remove (gsi, true);
1960 /* If the stmt can throw use a new temporary for the assignment
1961 to a LHS. This makes sure the old value of the LHS is
1962 available on the EH edge. Only do so for statements that
1963 potentially fall thru (no noreturn calls e.g.), otherwise
1964 this new assignment might create fake fallthru regions. */
1965 if (stmt_could_throw_p (stmt)
1966 && gimple_has_lhs (stmt)
1967 && gimple_stmt_may_fallthru (stmt)
1968 && !tree_could_throw_p (gimple_get_lhs (stmt))
1969 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt))))
1971 tree lhs = gimple_get_lhs (stmt);
1972 tree tmp = create_tmp_var (TREE_TYPE (lhs), NULL);
1973 gimple s = gimple_build_assign (lhs, tmp);
1974 gimple_set_location (s, gimple_location (stmt));
1975 gimple_set_block (s, gimple_block (stmt));
1976 gimple_set_lhs (stmt, tmp);
1977 if (TREE_CODE (TREE_TYPE (tmp)) == COMPLEX_TYPE
1978 || TREE_CODE (TREE_TYPE (tmp)) == VECTOR_TYPE)
1979 DECL_GIMPLE_REG_P (tmp) = 1;
1980 gsi_insert_after (gsi, s, GSI_SAME_STMT);
1982 /* Look for things that can throw exceptions, and record them. */
1983 if (state->cur_region && stmt_could_throw_p (stmt))
1985 record_stmt_eh_region (state->cur_region, stmt);
1986 note_eh_region_may_contain_throw (state->cur_region);
1993 maybe_record_in_goto_queue (state, stmt);
1997 verify_norecord_switch_expr (state, stmt);
2001 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
2002 replace = lower_try_finally (state, stmt);
2005 x = gimple_seq_first_stmt (gimple_try_cleanup (stmt));
2008 replace = gimple_try_eval (stmt);
2009 lower_eh_constructs_1 (state, replace);
2012 switch (gimple_code (x))
2015 replace = lower_catch (state, stmt);
2017 case GIMPLE_EH_FILTER:
2018 replace = lower_eh_filter (state, stmt);
2020 case GIMPLE_EH_MUST_NOT_THROW:
2021 replace = lower_eh_must_not_throw (state, stmt);
2023 case GIMPLE_EH_ELSE:
2024 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2027 replace = lower_cleanup (state, stmt);
2032 /* Remove the old stmt and insert the transformed sequence
2034 gsi_insert_seq_before (gsi, replace, GSI_SAME_STMT);
2035 gsi_remove (gsi, true);
2037 /* Return since we don't want gsi_next () */
2040 case GIMPLE_EH_ELSE:
2041 /* We should be eliminating this in lower_try_finally et al. */
2045 /* A type, a decl, or some kind of statement that we're not
2046 interested in. Don't walk them. */
2053 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2056 lower_eh_constructs_1 (struct leh_state *state, gimple_seq seq)
2058 gimple_stmt_iterator gsi;
2059 for (gsi = gsi_start (seq); !gsi_end_p (gsi);)
2060 lower_eh_constructs_2 (state, &gsi);
2064 lower_eh_constructs (void)
2066 struct leh_state null_state;
2069 bodyp = gimple_body (current_function_decl);
2073 finally_tree = htab_create (31, struct_ptr_hash, struct_ptr_eq, free);
2074 eh_region_may_contain_throw_map = BITMAP_ALLOC (NULL);
2075 memset (&null_state, 0, sizeof (null_state));
2077 collect_finally_tree_1 (bodyp, NULL);
2078 lower_eh_constructs_1 (&null_state, bodyp);
2080 /* We assume there's a return statement, or something, at the end of
2081 the function, and thus ploping the EH sequence afterward won't
2083 gcc_assert (!gimple_seq_may_fallthru (bodyp));
2084 gimple_seq_add_seq (&bodyp, eh_seq);
2086 /* We assume that since BODYP already existed, adding EH_SEQ to it
2087 didn't change its value, and we don't have to re-set the function. */
2088 gcc_assert (bodyp == gimple_body (current_function_decl));
2090 htab_delete (finally_tree);
2091 BITMAP_FREE (eh_region_may_contain_throw_map);
2094 /* If this function needs a language specific EH personality routine
2095 and the frontend didn't already set one do so now. */
2096 if (function_needs_eh_personality (cfun) == eh_personality_lang
2097 && !DECL_FUNCTION_PERSONALITY (current_function_decl))
2098 DECL_FUNCTION_PERSONALITY (current_function_decl)
2099 = lang_hooks.eh_personality ();
2104 struct gimple_opt_pass pass_lower_eh =
2110 lower_eh_constructs, /* execute */
2113 0, /* static_pass_number */
2114 TV_TREE_EH, /* tv_id */
2115 PROP_gimple_lcf, /* properties_required */
2116 PROP_gimple_leh, /* properties_provided */
2117 0, /* properties_destroyed */
2118 0, /* todo_flags_start */
2119 0 /* todo_flags_finish */
2123 /* Create the multiple edges from an EH_DISPATCH statement to all of
2124 the possible handlers for its EH region. Return true if there's
2125 no fallthru edge; false if there is. */
2128 make_eh_dispatch_edges (gimple stmt)
2132 basic_block src, dst;
2134 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
2135 src = gimple_bb (stmt);
2140 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
2142 dst = label_to_block (c->label);
2143 make_edge (src, dst, 0);
2145 /* A catch-all handler doesn't have a fallthru. */
2146 if (c->type_list == NULL)
2151 case ERT_ALLOWED_EXCEPTIONS:
2152 dst = label_to_block (r->u.allowed.label);
2153 make_edge (src, dst, 0);
2163 /* Create the single EH edge from STMT to its nearest landing pad,
2164 if there is such a landing pad within the current function. */
2167 make_eh_edges (gimple stmt)
2169 basic_block src, dst;
2173 lp_nr = lookup_stmt_eh_lp (stmt);
2177 lp = get_eh_landing_pad_from_number (lp_nr);
2178 gcc_assert (lp != NULL);
2180 src = gimple_bb (stmt);
2181 dst = label_to_block (lp->post_landing_pad);
2182 make_edge (src, dst, EDGE_EH);
2185 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2186 do not actually perform the final edge redirection.
2188 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2189 we intend to change the destination EH region as well; this means
2190 EH_LANDING_PAD_NR must already be set on the destination block label.
2191 If false, we're being called from generic cfg manipulation code and we
2192 should preserve our place within the region tree. */
2195 redirect_eh_edge_1 (edge edge_in, basic_block new_bb, bool change_region)
2197 eh_landing_pad old_lp, new_lp;
2200 int old_lp_nr, new_lp_nr;
2201 tree old_label, new_label;
2205 old_bb = edge_in->dest;
2206 old_label = gimple_block_label (old_bb);
2207 old_lp_nr = EH_LANDING_PAD_NR (old_label);
2208 gcc_assert (old_lp_nr > 0);
2209 old_lp = get_eh_landing_pad_from_number (old_lp_nr);
2211 throw_stmt = last_stmt (edge_in->src);
2212 gcc_assert (lookup_stmt_eh_lp (throw_stmt) == old_lp_nr);
2214 new_label = gimple_block_label (new_bb);
2216 /* Look for an existing region that might be using NEW_BB already. */
2217 new_lp_nr = EH_LANDING_PAD_NR (new_label);
2220 new_lp = get_eh_landing_pad_from_number (new_lp_nr);
2221 gcc_assert (new_lp);
2223 /* Unless CHANGE_REGION is true, the new and old landing pad
2224 had better be associated with the same EH region. */
2225 gcc_assert (change_region || new_lp->region == old_lp->region);
2230 gcc_assert (!change_region);
2233 /* Notice when we redirect the last EH edge away from OLD_BB. */
2234 FOR_EACH_EDGE (e, ei, old_bb->preds)
2235 if (e != edge_in && (e->flags & EDGE_EH))
2240 /* NEW_LP already exists. If there are still edges into OLD_LP,
2241 there's nothing to do with the EH tree. If there are no more
2242 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2243 If CHANGE_REGION is true, then our caller is expecting to remove
2245 if (e == NULL && !change_region)
2246 remove_eh_landing_pad (old_lp);
2250 /* No correct landing pad exists. If there are no more edges
2251 into OLD_LP, then we can simply re-use the existing landing pad.
2252 Otherwise, we have to create a new landing pad. */
2255 EH_LANDING_PAD_NR (old_lp->post_landing_pad) = 0;
2259 new_lp = gen_eh_landing_pad (old_lp->region);
2260 new_lp->post_landing_pad = new_label;
2261 EH_LANDING_PAD_NR (new_label) = new_lp->index;
2264 /* Maybe move the throwing statement to the new region. */
2265 if (old_lp != new_lp)
2267 remove_stmt_from_eh_lp (throw_stmt);
2268 add_stmt_to_eh_lp (throw_stmt, new_lp->index);
2272 /* Redirect EH edge E to NEW_BB. */
2275 redirect_eh_edge (edge edge_in, basic_block new_bb)
2277 redirect_eh_edge_1 (edge_in, new_bb, false);
2278 return ssa_redirect_edge (edge_in, new_bb);
2281 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2282 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2283 The actual edge update will happen in the caller. */
2286 redirect_eh_dispatch_edge (gimple stmt, edge e, basic_block new_bb)
2288 tree new_lab = gimple_block_label (new_bb);
2289 bool any_changed = false;
2294 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
2298 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
2300 old_bb = label_to_block (c->label);
2301 if (old_bb == e->dest)
2309 case ERT_ALLOWED_EXCEPTIONS:
2310 old_bb = label_to_block (r->u.allowed.label);
2311 gcc_assert (old_bb == e->dest);
2312 r->u.allowed.label = new_lab;
2320 gcc_assert (any_changed);
2323 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2326 operation_could_trap_helper_p (enum tree_code op,
2337 case TRUNC_DIV_EXPR:
2339 case FLOOR_DIV_EXPR:
2340 case ROUND_DIV_EXPR:
2341 case EXACT_DIV_EXPR:
2343 case FLOOR_MOD_EXPR:
2344 case ROUND_MOD_EXPR:
2345 case TRUNC_MOD_EXPR:
2347 if (honor_snans || honor_trapv)
2350 return flag_trapping_math;
2351 if (!TREE_CONSTANT (divisor) || integer_zerop (divisor))
2360 /* Some floating point comparisons may trap. */
2365 case UNORDERED_EXPR:
2375 case FIX_TRUNC_EXPR:
2376 /* Conversion of floating point might trap. */
2382 /* These operations don't trap with floating point. */
2390 /* Any floating arithmetic may trap. */
2391 if (fp_operation && flag_trapping_math)
2399 /* Constructing an object cannot trap. */
2403 /* Any floating arithmetic may trap. */
2404 if (fp_operation && flag_trapping_math)
2412 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2413 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2414 type operands that may trap. If OP is a division operator, DIVISOR contains
2415 the value of the divisor. */
2418 operation_could_trap_p (enum tree_code op, bool fp_operation, bool honor_trapv,
2421 bool honor_nans = (fp_operation && flag_trapping_math
2422 && !flag_finite_math_only);
2423 bool honor_snans = fp_operation && flag_signaling_nans != 0;
2426 if (TREE_CODE_CLASS (op) != tcc_comparison
2427 && TREE_CODE_CLASS (op) != tcc_unary
2428 && TREE_CODE_CLASS (op) != tcc_binary)
2431 return operation_could_trap_helper_p (op, fp_operation, honor_trapv,
2432 honor_nans, honor_snans, divisor,
2436 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2437 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2438 This routine expects only GIMPLE lhs or rhs input. */
2441 tree_could_trap_p (tree expr)
2443 enum tree_code code;
2444 bool fp_operation = false;
2445 bool honor_trapv = false;
2446 tree t, base, div = NULL_TREE;
2451 code = TREE_CODE (expr);
2452 t = TREE_TYPE (expr);
2456 if (COMPARISON_CLASS_P (expr))
2457 fp_operation = FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0)));
2459 fp_operation = FLOAT_TYPE_P (t);
2460 honor_trapv = INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t);
2463 if (TREE_CODE_CLASS (code) == tcc_binary)
2464 div = TREE_OPERAND (expr, 1);
2465 if (operation_could_trap_p (code, fp_operation, honor_trapv, div))
2471 case TARGET_MEM_REF:
2472 if (TREE_CODE (TMR_BASE (expr)) == ADDR_EXPR
2473 && !TMR_INDEX (expr) && !TMR_INDEX2 (expr))
2475 return !TREE_THIS_NOTRAP (expr);
2481 case VIEW_CONVERT_EXPR:
2482 case WITH_SIZE_EXPR:
2483 expr = TREE_OPERAND (expr, 0);
2484 code = TREE_CODE (expr);
2487 case ARRAY_RANGE_REF:
2488 base = TREE_OPERAND (expr, 0);
2489 if (tree_could_trap_p (base))
2491 if (TREE_THIS_NOTRAP (expr))
2493 return !range_in_array_bounds_p (expr);
2496 base = TREE_OPERAND (expr, 0);
2497 if (tree_could_trap_p (base))
2499 if (TREE_THIS_NOTRAP (expr))
2501 return !in_array_bounds_p (expr);
2504 if (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR)
2508 return !TREE_THIS_NOTRAP (expr);
2511 return TREE_THIS_VOLATILE (expr);
2514 t = get_callee_fndecl (expr);
2515 /* Assume that calls to weak functions may trap. */
2516 if (!t || !DECL_P (t))
2519 return tree_could_trap_p (t);
2523 /* Assume that accesses to weak functions may trap, unless we know
2524 they are certainly defined in current TU or in some other
2526 if (DECL_WEAK (expr))
2528 struct cgraph_node *node;
2529 if (!DECL_EXTERNAL (expr))
2531 node = cgraph_function_node (cgraph_get_node (expr), NULL);
2532 if (node && node->in_other_partition)
2539 /* Assume that accesses to weak vars may trap, unless we know
2540 they are certainly defined in current TU or in some other
2542 if (DECL_WEAK (expr))
2544 struct varpool_node *node;
2545 if (!DECL_EXTERNAL (expr))
2547 node = varpool_variable_node (varpool_get_node (expr), NULL);
2548 if (node && node->in_other_partition)
2560 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2561 an assignment or a conditional) may throw. */
2564 stmt_could_throw_1_p (gimple stmt)
2566 enum tree_code code = gimple_expr_code (stmt);
2567 bool honor_nans = false;
2568 bool honor_snans = false;
2569 bool fp_operation = false;
2570 bool honor_trapv = false;
2575 if (TREE_CODE_CLASS (code) == tcc_comparison
2576 || TREE_CODE_CLASS (code) == tcc_unary
2577 || TREE_CODE_CLASS (code) == tcc_binary)
2579 if (is_gimple_assign (stmt)
2580 && TREE_CODE_CLASS (code) == tcc_comparison)
2581 t = TREE_TYPE (gimple_assign_rhs1 (stmt));
2582 else if (gimple_code (stmt) == GIMPLE_COND)
2583 t = TREE_TYPE (gimple_cond_lhs (stmt));
2585 t = gimple_expr_type (stmt);
2586 fp_operation = FLOAT_TYPE_P (t);
2589 honor_nans = flag_trapping_math && !flag_finite_math_only;
2590 honor_snans = flag_signaling_nans != 0;
2592 else if (INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t))
2596 /* Check if the main expression may trap. */
2597 t = is_gimple_assign (stmt) ? gimple_assign_rhs2 (stmt) : NULL;
2598 ret = operation_could_trap_helper_p (code, fp_operation, honor_trapv,
2599 honor_nans, honor_snans, t,
2604 /* If the expression does not trap, see if any of the individual operands may
2606 for (i = 0; i < gimple_num_ops (stmt); i++)
2607 if (tree_could_trap_p (gimple_op (stmt, i)))
2614 /* Return true if statement STMT could throw an exception. */
2617 stmt_could_throw_p (gimple stmt)
2619 if (!flag_exceptions)
2622 /* The only statements that can throw an exception are assignments,
2623 conditionals, calls, resx, and asms. */
2624 switch (gimple_code (stmt))
2630 return !gimple_call_nothrow_p (stmt);
2634 if (!cfun->can_throw_non_call_exceptions)
2636 return stmt_could_throw_1_p (stmt);
2639 if (!cfun->can_throw_non_call_exceptions)
2641 return gimple_asm_volatile_p (stmt);
2649 /* Return true if expression T could throw an exception. */
2652 tree_could_throw_p (tree t)
2654 if (!flag_exceptions)
2656 if (TREE_CODE (t) == MODIFY_EXPR)
2658 if (cfun->can_throw_non_call_exceptions
2659 && tree_could_trap_p (TREE_OPERAND (t, 0)))
2661 t = TREE_OPERAND (t, 1);
2664 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2665 t = TREE_OPERAND (t, 0);
2666 if (TREE_CODE (t) == CALL_EXPR)
2667 return (call_expr_flags (t) & ECF_NOTHROW) == 0;
2668 if (cfun->can_throw_non_call_exceptions)
2669 return tree_could_trap_p (t);
2673 /* Return true if STMT can throw an exception that is not caught within
2674 the current function (CFUN). */
2677 stmt_can_throw_external (gimple stmt)
2681 if (!stmt_could_throw_p (stmt))
2684 lp_nr = lookup_stmt_eh_lp (stmt);
2688 /* Return true if STMT can throw an exception that is caught within
2689 the current function (CFUN). */
2692 stmt_can_throw_internal (gimple stmt)
2696 if (!stmt_could_throw_p (stmt))
2699 lp_nr = lookup_stmt_eh_lp (stmt);
2703 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2704 remove any entry it might have from the EH table. Return true if
2705 any change was made. */
2708 maybe_clean_eh_stmt_fn (struct function *ifun, gimple stmt)
2710 if (stmt_could_throw_p (stmt))
2712 return remove_stmt_from_eh_lp_fn (ifun, stmt);
2715 /* Likewise, but always use the current function. */
2718 maybe_clean_eh_stmt (gimple stmt)
2720 return maybe_clean_eh_stmt_fn (cfun, stmt);
2723 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2724 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2725 in the table if it should be in there. Return TRUE if a replacement was
2726 done that my require an EH edge purge. */
2729 maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt)
2731 int lp_nr = lookup_stmt_eh_lp (old_stmt);
2735 bool new_stmt_could_throw = stmt_could_throw_p (new_stmt);
2737 if (new_stmt == old_stmt && new_stmt_could_throw)
2740 remove_stmt_from_eh_lp (old_stmt);
2741 if (new_stmt_could_throw)
2743 add_stmt_to_eh_lp (new_stmt, lp_nr);
2753 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statment NEW_STMT
2754 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2755 operand is the return value of duplicate_eh_regions. */
2758 maybe_duplicate_eh_stmt_fn (struct function *new_fun, gimple new_stmt,
2759 struct function *old_fun, gimple old_stmt,
2760 struct pointer_map_t *map, int default_lp_nr)
2762 int old_lp_nr, new_lp_nr;
2765 if (!stmt_could_throw_p (new_stmt))
2768 old_lp_nr = lookup_stmt_eh_lp_fn (old_fun, old_stmt);
2771 if (default_lp_nr == 0)
2773 new_lp_nr = default_lp_nr;
2775 else if (old_lp_nr > 0)
2777 eh_landing_pad old_lp, new_lp;
2779 old_lp = VEC_index (eh_landing_pad, old_fun->eh->lp_array, old_lp_nr);
2780 slot = pointer_map_contains (map, old_lp);
2781 new_lp = (eh_landing_pad) *slot;
2782 new_lp_nr = new_lp->index;
2786 eh_region old_r, new_r;
2788 old_r = VEC_index (eh_region, old_fun->eh->region_array, -old_lp_nr);
2789 slot = pointer_map_contains (map, old_r);
2790 new_r = (eh_region) *slot;
2791 new_lp_nr = -new_r->index;
2794 add_stmt_to_eh_lp_fn (new_fun, new_stmt, new_lp_nr);
2798 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2799 and thus no remapping is required. */
2802 maybe_duplicate_eh_stmt (gimple new_stmt, gimple old_stmt)
2806 if (!stmt_could_throw_p (new_stmt))
2809 lp_nr = lookup_stmt_eh_lp (old_stmt);
2813 add_stmt_to_eh_lp (new_stmt, lp_nr);
2817 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2818 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2819 this only handles handlers consisting of a single call, as that's the
2820 important case for C++: a destructor call for a particular object showing
2821 up in multiple handlers. */
2824 same_handler_p (gimple_seq oneh, gimple_seq twoh)
2826 gimple_stmt_iterator gsi;
2830 gsi = gsi_start (oneh);
2831 if (!gsi_one_before_end_p (gsi))
2833 ones = gsi_stmt (gsi);
2835 gsi = gsi_start (twoh);
2836 if (!gsi_one_before_end_p (gsi))
2838 twos = gsi_stmt (gsi);
2840 if (!is_gimple_call (ones)
2841 || !is_gimple_call (twos)
2842 || gimple_call_lhs (ones)
2843 || gimple_call_lhs (twos)
2844 || gimple_call_chain (ones)
2845 || gimple_call_chain (twos)
2846 || !gimple_call_same_target_p (ones, twos)
2847 || gimple_call_num_args (ones) != gimple_call_num_args (twos))
2850 for (ai = 0; ai < gimple_call_num_args (ones); ++ai)
2851 if (!operand_equal_p (gimple_call_arg (ones, ai),
2852 gimple_call_arg (twos, ai), 0))
2859 try { A() } finally { try { ~B() } catch { ~A() } }
2860 try { ... } finally { ~A() }
2862 try { A() } catch { ~B() }
2863 try { ~B() ... } finally { ~A() }
2865 This occurs frequently in C++, where A is a local variable and B is a
2866 temporary used in the initializer for A. */
2869 optimize_double_finally (gimple one, gimple two)
2872 gimple_stmt_iterator gsi;
2874 gsi = gsi_start (gimple_try_cleanup (one));
2875 if (!gsi_one_before_end_p (gsi))
2878 oneh = gsi_stmt (gsi);
2879 if (gimple_code (oneh) != GIMPLE_TRY
2880 || gimple_try_kind (oneh) != GIMPLE_TRY_CATCH)
2883 if (same_handler_p (gimple_try_cleanup (oneh), gimple_try_cleanup (two)))
2885 gimple_seq seq = gimple_try_eval (oneh);
2887 gimple_try_set_cleanup (one, seq);
2888 gimple_try_set_kind (one, GIMPLE_TRY_CATCH);
2889 seq = copy_gimple_seq_and_replace_locals (seq);
2890 gimple_seq_add_seq (&seq, gimple_try_eval (two));
2891 gimple_try_set_eval (two, seq);
2895 /* Perform EH refactoring optimizations that are simpler to do when code
2896 flow has been lowered but EH structures haven't. */
2899 refactor_eh_r (gimple_seq seq)
2901 gimple_stmt_iterator gsi;
2906 gsi = gsi_start (seq);
2910 if (gsi_end_p (gsi))
2913 two = gsi_stmt (gsi);
2916 && gimple_code (one) == GIMPLE_TRY
2917 && gimple_code (two) == GIMPLE_TRY
2918 && gimple_try_kind (one) == GIMPLE_TRY_FINALLY
2919 && gimple_try_kind (two) == GIMPLE_TRY_FINALLY)
2920 optimize_double_finally (one, two);
2922 switch (gimple_code (one))
2925 refactor_eh_r (gimple_try_eval (one));
2926 refactor_eh_r (gimple_try_cleanup (one));
2929 refactor_eh_r (gimple_catch_handler (one));
2931 case GIMPLE_EH_FILTER:
2932 refactor_eh_r (gimple_eh_filter_failure (one));
2934 case GIMPLE_EH_ELSE:
2935 refactor_eh_r (gimple_eh_else_n_body (one));
2936 refactor_eh_r (gimple_eh_else_e_body (one));
2951 refactor_eh_r (gimple_body (current_function_decl));
2956 gate_refactor_eh (void)
2958 return flag_exceptions != 0;
2961 struct gimple_opt_pass pass_refactor_eh =
2966 gate_refactor_eh, /* gate */
2967 refactor_eh, /* execute */
2970 0, /* static_pass_number */
2971 TV_TREE_EH, /* tv_id */
2972 PROP_gimple_lcf, /* properties_required */
2973 0, /* properties_provided */
2974 0, /* properties_destroyed */
2975 0, /* todo_flags_start */
2976 0 /* todo_flags_finish */
2980 /* At the end of gimple optimization, we can lower RESX. */
2983 lower_resx (basic_block bb, gimple stmt, struct pointer_map_t *mnt_map)
2986 eh_region src_r, dst_r;
2987 gimple_stmt_iterator gsi;
2992 lp_nr = lookup_stmt_eh_lp (stmt);
2994 dst_r = get_eh_region_from_lp_number (lp_nr);
2998 src_r = get_eh_region_from_number (gimple_resx_region (stmt));
2999 gsi = gsi_last_bb (bb);
3003 /* We can wind up with no source region when pass_cleanup_eh shows
3004 that there are no entries into an eh region and deletes it, but
3005 then the block that contains the resx isn't removed. This can
3006 happen without optimization when the switch statement created by
3007 lower_try_finally_switch isn't simplified to remove the eh case.
3009 Resolve this by expanding the resx node to an abort. */
3011 fn = builtin_decl_implicit (BUILT_IN_TRAP);
3012 x = gimple_build_call (fn, 0);
3013 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3015 while (EDGE_COUNT (bb->succs) > 0)
3016 remove_edge (EDGE_SUCC (bb, 0));
3020 /* When we have a destination region, we resolve this by copying
3021 the excptr and filter values into place, and changing the edge
3022 to immediately after the landing pad. */
3031 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3032 the failure decl into a new block, if needed. */
3033 gcc_assert (dst_r->type == ERT_MUST_NOT_THROW);
3035 slot = pointer_map_contains (mnt_map, dst_r);
3038 gimple_stmt_iterator gsi2;
3040 new_bb = create_empty_bb (bb);
3041 lab = gimple_block_label (new_bb);
3042 gsi2 = gsi_start_bb (new_bb);
3044 fn = dst_r->u.must_not_throw.failure_decl;
3045 x = gimple_build_call (fn, 0);
3046 gimple_set_location (x, dst_r->u.must_not_throw.failure_loc);
3047 gsi_insert_after (&gsi2, x, GSI_CONTINUE_LINKING);
3049 slot = pointer_map_insert (mnt_map, dst_r);
3055 new_bb = label_to_block (lab);
3058 gcc_assert (EDGE_COUNT (bb->succs) == 0);
3059 e = make_edge (bb, new_bb, EDGE_FALLTHRU);
3060 e->count = bb->count;
3061 e->probability = REG_BR_PROB_BASE;
3066 tree dst_nr = build_int_cst (integer_type_node, dst_r->index);
3068 fn = builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES);
3069 src_nr = build_int_cst (integer_type_node, src_r->index);
3070 x = gimple_build_call (fn, 2, dst_nr, src_nr);
3071 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3073 /* Update the flags for the outgoing edge. */
3074 e = single_succ_edge (bb);
3075 gcc_assert (e->flags & EDGE_EH);
3076 e->flags = (e->flags & ~EDGE_EH) | EDGE_FALLTHRU;
3078 /* If there are no more EH users of the landing pad, delete it. */
3079 FOR_EACH_EDGE (e, ei, e->dest->preds)
3080 if (e->flags & EDGE_EH)
3084 eh_landing_pad lp = get_eh_landing_pad_from_number (lp_nr);
3085 remove_eh_landing_pad (lp);
3095 /* When we don't have a destination region, this exception escapes
3096 up the call chain. We resolve this by generating a call to the
3097 _Unwind_Resume library function. */
3099 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3100 with no arguments for C++ and Java. Check for that. */
3101 if (src_r->use_cxa_end_cleanup)
3103 fn = builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP);
3104 x = gimple_build_call (fn, 0);
3105 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3109 fn = builtin_decl_implicit (BUILT_IN_EH_POINTER);
3110 src_nr = build_int_cst (integer_type_node, src_r->index);
3111 x = gimple_build_call (fn, 1, src_nr);
3112 var = create_tmp_var (ptr_type_node, NULL);
3113 var = make_ssa_name (var, x);
3114 gimple_call_set_lhs (x, var);
3115 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3117 fn = builtin_decl_implicit (BUILT_IN_UNWIND_RESUME);
3118 x = gimple_build_call (fn, 1, var);
3119 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3122 gcc_assert (EDGE_COUNT (bb->succs) == 0);
3125 gsi_remove (&gsi, true);
3131 execute_lower_resx (void)
3134 struct pointer_map_t *mnt_map;
3135 bool dominance_invalidated = false;
3136 bool any_rewritten = false;
3138 mnt_map = pointer_map_create ();
3142 gimple last = last_stmt (bb);
3143 if (last && is_gimple_resx (last))
3145 dominance_invalidated |= lower_resx (bb, last, mnt_map);
3146 any_rewritten = true;
3150 pointer_map_destroy (mnt_map);
3152 if (dominance_invalidated)
3154 free_dominance_info (CDI_DOMINATORS);
3155 free_dominance_info (CDI_POST_DOMINATORS);
3158 return any_rewritten ? TODO_update_ssa_only_virtuals : 0;
3162 gate_lower_resx (void)
3164 return flag_exceptions != 0;
3167 struct gimple_opt_pass pass_lower_resx =
3172 gate_lower_resx, /* gate */
3173 execute_lower_resx, /* execute */
3176 0, /* static_pass_number */
3177 TV_TREE_EH, /* tv_id */
3178 PROP_gimple_lcf, /* properties_required */
3179 0, /* properties_provided */
3180 0, /* properties_destroyed */
3181 0, /* todo_flags_start */
3182 TODO_verify_flow /* todo_flags_finish */
3186 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3190 optimize_clobbers (basic_block bb)
3192 gimple_stmt_iterator gsi = gsi_last_bb (bb);
3193 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3195 gimple stmt = gsi_stmt (gsi);
3196 if (is_gimple_debug (stmt))
3198 if (!gimple_clobber_p (stmt)
3199 || TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME)
3201 unlink_stmt_vdef (stmt);
3202 gsi_remove (&gsi, true);
3203 release_defs (stmt);
3207 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3208 internal throw to successor BB. */
3211 sink_clobbers (basic_block bb)
3215 gimple_stmt_iterator gsi, dgsi;
3217 bool any_clobbers = false;
3219 /* Only optimize if BB has a single EH successor and
3220 all predecessor edges are EH too. */
3221 if (!single_succ_p (bb)
3222 || (single_succ_edge (bb)->flags & EDGE_EH) == 0)
3225 FOR_EACH_EDGE (e, ei, bb->preds)
3227 if ((e->flags & EDGE_EH) == 0)
3231 /* And BB contains only CLOBBER stmts before the final
3233 gsi = gsi_last_bb (bb);
3234 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3236 gimple stmt = gsi_stmt (gsi);
3237 if (is_gimple_debug (stmt))
3239 if (gimple_code (stmt) == GIMPLE_LABEL)
3241 if (!gimple_clobber_p (stmt)
3242 || TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME)
3244 any_clobbers = true;
3249 succbb = single_succ (bb);
3250 dgsi = gsi_after_labels (succbb);
3251 gsi = gsi_last_bb (bb);
3252 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3254 gimple stmt = gsi_stmt (gsi);
3256 if (is_gimple_debug (stmt))
3258 if (gimple_code (stmt) == GIMPLE_LABEL)
3260 unlink_stmt_vdef (stmt);
3261 gsi_remove (&gsi, false);
3262 vdef = gimple_vdef (stmt);
3263 if (vdef && TREE_CODE (vdef) == SSA_NAME)
3265 vdef = SSA_NAME_VAR (vdef);
3266 mark_sym_for_renaming (vdef);
3267 gimple_set_vdef (stmt, vdef);
3268 gimple_set_vuse (stmt, vdef);
3270 release_defs (stmt);
3271 gsi_insert_before (&dgsi, stmt, GSI_SAME_STMT);
3274 return TODO_update_ssa_only_virtuals;
3277 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3278 we have found some duplicate labels and removed some edges. */
3281 lower_eh_dispatch (basic_block src, gimple stmt)
3283 gimple_stmt_iterator gsi;
3288 bool redirected = false;
3290 region_nr = gimple_eh_dispatch_region (stmt);
3291 r = get_eh_region_from_number (region_nr);
3293 gsi = gsi_last_bb (src);
3299 VEC (tree, heap) *labels = NULL;
3300 tree default_label = NULL;
3304 struct pointer_set_t *seen_values = pointer_set_create ();
3306 /* Collect the labels for a switch. Zero the post_landing_pad
3307 field becase we'll no longer have anything keeping these labels
3308 in existance and the optimizer will be free to merge these
3310 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
3312 tree tp_node, flt_node, lab = c->label;
3313 bool have_label = false;
3316 tp_node = c->type_list;
3317 flt_node = c->filter_list;
3319 if (tp_node == NULL)
3321 default_label = lab;
3326 /* Filter out duplicate labels that arise when this handler
3327 is shadowed by an earlier one. When no labels are
3328 attached to the handler anymore, we remove
3329 the corresponding edge and then we delete unreachable
3330 blocks at the end of this pass. */
3331 if (! pointer_set_contains (seen_values, TREE_VALUE (flt_node)))
3333 tree t = build_case_label (TREE_VALUE (flt_node),
3335 VEC_safe_push (tree, heap, labels, t);
3336 pointer_set_insert (seen_values, TREE_VALUE (flt_node));
3340 tp_node = TREE_CHAIN (tp_node);
3341 flt_node = TREE_CHAIN (flt_node);
3346 remove_edge (find_edge (src, label_to_block (lab)));
3351 /* Clean up the edge flags. */
3352 FOR_EACH_EDGE (e, ei, src->succs)
3354 if (e->flags & EDGE_FALLTHRU)
3356 /* If there was no catch-all, use the fallthru edge. */
3357 if (default_label == NULL)
3358 default_label = gimple_block_label (e->dest);
3359 e->flags &= ~EDGE_FALLTHRU;
3362 gcc_assert (default_label != NULL);
3364 /* Don't generate a switch if there's only a default case.
3365 This is common in the form of try { A; } catch (...) { B; }. */
3368 e = single_succ_edge (src);
3369 e->flags |= EDGE_FALLTHRU;
3373 fn = builtin_decl_implicit (BUILT_IN_EH_FILTER);
3374 x = gimple_build_call (fn, 1, build_int_cst (integer_type_node,
3376 filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
3377 filter = make_ssa_name (filter, x);
3378 gimple_call_set_lhs (x, filter);
3379 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3381 /* Turn the default label into a default case. */
3382 default_label = build_case_label (NULL, NULL, default_label);
3383 sort_case_labels (labels);
3385 x = gimple_build_switch_vec (filter, default_label, labels);
3386 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3388 VEC_free (tree, heap, labels);
3390 pointer_set_destroy (seen_values);
3394 case ERT_ALLOWED_EXCEPTIONS:
3396 edge b_e = BRANCH_EDGE (src);
3397 edge f_e = FALLTHRU_EDGE (src);
3399 fn = builtin_decl_implicit (BUILT_IN_EH_FILTER);
3400 x = gimple_build_call (fn, 1, build_int_cst (integer_type_node,
3402 filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
3403 filter = make_ssa_name (filter, x);
3404 gimple_call_set_lhs (x, filter);
3405 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3407 r->u.allowed.label = NULL;
3408 x = gimple_build_cond (EQ_EXPR, filter,
3409 build_int_cst (TREE_TYPE (filter),
3410 r->u.allowed.filter),
3411 NULL_TREE, NULL_TREE);
3412 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3414 b_e->flags = b_e->flags | EDGE_TRUE_VALUE;
3415 f_e->flags = (f_e->flags & ~EDGE_FALLTHRU) | EDGE_FALSE_VALUE;
3423 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3424 gsi_remove (&gsi, true);
3429 execute_lower_eh_dispatch (void)
3433 bool redirected = false;
3435 assign_filter_values ();
3439 gimple last = last_stmt (bb);
3442 if (gimple_code (last) == GIMPLE_EH_DISPATCH)
3444 redirected |= lower_eh_dispatch (bb, last);
3445 flags |= TODO_update_ssa_only_virtuals;
3447 else if (gimple_code (last) == GIMPLE_RESX)
3449 if (stmt_can_throw_external (last))
3450 optimize_clobbers (bb);
3452 flags |= sink_clobbers (bb);
3457 delete_unreachable_blocks ();
3462 gate_lower_eh_dispatch (void)
3464 return cfun->eh->region_tree != NULL;
3467 struct gimple_opt_pass pass_lower_eh_dispatch =
3471 "ehdisp", /* name */
3472 gate_lower_eh_dispatch, /* gate */
3473 execute_lower_eh_dispatch, /* execute */
3476 0, /* static_pass_number */
3477 TV_TREE_EH, /* tv_id */
3478 PROP_gimple_lcf, /* properties_required */
3479 0, /* properties_provided */
3480 0, /* properties_destroyed */
3481 0, /* todo_flags_start */
3482 TODO_verify_flow /* todo_flags_finish */
3486 /* Walk statements, see what regions are really referenced and remove
3487 those that are unused. */
3490 remove_unreachable_handlers (void)
3492 sbitmap r_reachable, lp_reachable;
3498 r_reachable = sbitmap_alloc (VEC_length (eh_region, cfun->eh->region_array));
3500 = sbitmap_alloc (VEC_length (eh_landing_pad, cfun->eh->lp_array));
3501 sbitmap_zero (r_reachable);
3502 sbitmap_zero (lp_reachable);
3506 gimple_stmt_iterator gsi;
3508 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
3510 gimple stmt = gsi_stmt (gsi);
3511 lp_nr = lookup_stmt_eh_lp (stmt);
3513 /* Negative LP numbers are MUST_NOT_THROW regions which
3514 are not considered BB enders. */
3516 SET_BIT (r_reachable, -lp_nr);
3518 /* Positive LP numbers are real landing pads, are are BB enders. */
3521 gcc_assert (gsi_one_before_end_p (gsi));
3522 region = get_eh_region_from_lp_number (lp_nr);
3523 SET_BIT (r_reachable, region->index);
3524 SET_BIT (lp_reachable, lp_nr);
3527 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3528 switch (gimple_code (stmt))
3531 SET_BIT (r_reachable, gimple_resx_region (stmt));
3533 case GIMPLE_EH_DISPATCH:
3534 SET_BIT (r_reachable, gimple_eh_dispatch_region (stmt));
3544 fprintf (dump_file, "Before removal of unreachable regions:\n");
3545 dump_eh_tree (dump_file, cfun);
3546 fprintf (dump_file, "Reachable regions: ");
3547 dump_sbitmap_file (dump_file, r_reachable);
3548 fprintf (dump_file, "Reachable landing pads: ");
3549 dump_sbitmap_file (dump_file, lp_reachable);
3553 VEC_iterate (eh_region, cfun->eh->region_array, r_nr, region); ++r_nr)
3554 if (region && !TEST_BIT (r_reachable, r_nr))
3557 fprintf (dump_file, "Removing unreachable region %d\n", r_nr);
3558 remove_eh_handler (region);
3562 VEC_iterate (eh_landing_pad, cfun->eh->lp_array, lp_nr, lp); ++lp_nr)
3563 if (lp && !TEST_BIT (lp_reachable, lp_nr))
3566 fprintf (dump_file, "Removing unreachable landing pad %d\n", lp_nr);
3567 remove_eh_landing_pad (lp);
3572 fprintf (dump_file, "\n\nAfter removal of unreachable regions:\n");
3573 dump_eh_tree (dump_file, cfun);
3574 fprintf (dump_file, "\n\n");
3577 sbitmap_free (r_reachable);
3578 sbitmap_free (lp_reachable);
3580 #ifdef ENABLE_CHECKING
3581 verify_eh_tree (cfun);
3585 /* Remove unreachable handlers if any landing pads have been removed after
3586 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3589 maybe_remove_unreachable_handlers (void)
3594 if (cfun->eh == NULL)
3597 for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
3598 if (lp && lp->post_landing_pad)
3600 if (label_to_block (lp->post_landing_pad) == NULL)
3602 remove_unreachable_handlers ();
3608 /* Remove regions that do not have landing pads. This assumes
3609 that remove_unreachable_handlers has already been run, and
3610 that we've just manipulated the landing pads since then. */
3613 remove_unreachable_handlers_no_lp (void)
3617 sbitmap r_reachable;
3620 r_reachable = sbitmap_alloc (VEC_length (eh_region, cfun->eh->region_array));
3621 sbitmap_zero (r_reachable);
3625 gimple stmt = last_stmt (bb);
3627 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3628 switch (gimple_code (stmt))
3631 SET_BIT (r_reachable, gimple_resx_region (stmt));
3633 case GIMPLE_EH_DISPATCH:
3634 SET_BIT (r_reachable, gimple_eh_dispatch_region (stmt));
3641 for (i = 1; VEC_iterate (eh_region, cfun->eh->region_array, i, r); ++i)
3642 if (r && r->landing_pads == NULL && r->type != ERT_MUST_NOT_THROW
3643 && !TEST_BIT (r_reachable, i))
3646 fprintf (dump_file, "Removing unreachable region %d\n", i);
3647 remove_eh_handler (r);
3650 sbitmap_free (r_reachable);
3653 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3654 optimisticaly split all sorts of edges, including EH edges. The
3655 optimization passes in between may not have needed them; if not,
3656 we should undo the split.
3658 Recognize this case by having one EH edge incoming to the BB and
3659 one normal edge outgoing; BB should be empty apart from the
3660 post_landing_pad label.
3662 Note that this is slightly different from the empty handler case
3663 handled by cleanup_empty_eh, in that the actual handler may yet
3664 have actual code but the landing pad has been separated from the
3665 handler. As such, cleanup_empty_eh relies on this transformation
3666 having been done first. */
3669 unsplit_eh (eh_landing_pad lp)
3671 basic_block bb = label_to_block (lp->post_landing_pad);
3672 gimple_stmt_iterator gsi;
3675 /* Quickly check the edge counts on BB for singularity. */
3676 if (EDGE_COUNT (bb->preds) != 1 || EDGE_COUNT (bb->succs) != 1)
3678 e_in = EDGE_PRED (bb, 0);
3679 e_out = EDGE_SUCC (bb, 0);
3681 /* Input edge must be EH and output edge must be normal. */
3682 if ((e_in->flags & EDGE_EH) == 0 || (e_out->flags & EDGE_EH) != 0)
3685 /* The block must be empty except for the labels and debug insns. */
3686 gsi = gsi_after_labels (bb);
3687 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
3688 gsi_next_nondebug (&gsi);
3689 if (!gsi_end_p (gsi))
3692 /* The destination block must not already have a landing pad
3693 for a different region. */
3694 for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
3696 gimple stmt = gsi_stmt (gsi);
3700 if (gimple_code (stmt) != GIMPLE_LABEL)
3702 lab = gimple_label_label (stmt);
3703 lp_nr = EH_LANDING_PAD_NR (lab);
3704 if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
3708 /* The new destination block must not already be a destination of
3709 the source block, lest we merge fallthru and eh edges and get
3710 all sorts of confused. */
3711 if (find_edge (e_in->src, e_out->dest))
3714 /* ??? We can get degenerate phis due to cfg cleanups. I would have
3715 thought this should have been cleaned up by a phicprop pass, but
3716 that doesn't appear to handle virtuals. Propagate by hand. */
3717 if (!gimple_seq_empty_p (phi_nodes (bb)))
3719 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
3721 gimple use_stmt, phi = gsi_stmt (gsi);
3722 tree lhs = gimple_phi_result (phi);
3723 tree rhs = gimple_phi_arg_def (phi, 0);
3724 use_operand_p use_p;
3725 imm_use_iterator iter;
3727 FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
3729 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
3730 SET_USE (use_p, rhs);
3733 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
3734 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
3736 remove_phi_node (&gsi, true);
3740 if (dump_file && (dump_flags & TDF_DETAILS))
3741 fprintf (dump_file, "Unsplit EH landing pad %d to block %i.\n",
3742 lp->index, e_out->dest->index);
3744 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
3745 a successor edge, humor it. But do the real CFG change with the
3746 predecessor of E_OUT in order to preserve the ordering of arguments
3747 to the PHI nodes in E_OUT->DEST. */
3748 redirect_eh_edge_1 (e_in, e_out->dest, false);
3749 redirect_edge_pred (e_out, e_in->src);
3750 e_out->flags = e_in->flags;
3751 e_out->probability = e_in->probability;
3752 e_out->count = e_in->count;
3758 /* Examine each landing pad block and see if it matches unsplit_eh. */
3761 unsplit_all_eh (void)
3763 bool changed = false;
3767 for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
3769 changed |= unsplit_eh (lp);
3774 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
3775 to OLD_BB to NEW_BB; return true on success, false on failure.
3777 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
3778 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
3779 Virtual PHIs may be deleted and marked for renaming. */
3782 cleanup_empty_eh_merge_phis (basic_block new_bb, basic_block old_bb,
3783 edge old_bb_out, bool change_region)
3785 gimple_stmt_iterator ngsi, ogsi;
3788 bitmap rename_virts;
3789 bitmap ophi_handled;
3791 /* The destination block must not be a regular successor for any
3792 of the preds of the landing pad. Thus, avoid turning
3802 which CFG verification would choke on. See PR45172 and PR51089. */
3803 FOR_EACH_EDGE (e, ei, old_bb->preds)
3804 if (find_edge (e->src, new_bb))
3807 FOR_EACH_EDGE (e, ei, old_bb->preds)
3808 redirect_edge_var_map_clear (e);
3810 ophi_handled = BITMAP_ALLOC (NULL);
3811 rename_virts = BITMAP_ALLOC (NULL);
3813 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
3814 for the edges we're going to move. */
3815 for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); gsi_next (&ngsi))
3817 gimple ophi, nphi = gsi_stmt (ngsi);
3820 nresult = gimple_phi_result (nphi);
3821 nop = gimple_phi_arg_def (nphi, old_bb_out->dest_idx);
3823 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
3824 the source ssa_name. */
3826 for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
3828 ophi = gsi_stmt (ogsi);
3829 if (gimple_phi_result (ophi) == nop)
3834 /* If we did find the corresponding PHI, copy those inputs. */
3837 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
3838 if (!has_single_use (nop))
3840 imm_use_iterator imm_iter;
3841 use_operand_p use_p;
3843 FOR_EACH_IMM_USE_FAST (use_p, imm_iter, nop)
3845 if (!gimple_debug_bind_p (USE_STMT (use_p))
3846 && (gimple_code (USE_STMT (use_p)) != GIMPLE_PHI
3847 || gimple_bb (USE_STMT (use_p)) != new_bb))
3851 bitmap_set_bit (ophi_handled, SSA_NAME_VERSION (nop));
3852 FOR_EACH_EDGE (e, ei, old_bb->preds)
3857 if ((e->flags & EDGE_EH) == 0)
3859 oop = gimple_phi_arg_def (ophi, e->dest_idx);
3860 oloc = gimple_phi_arg_location (ophi, e->dest_idx);
3861 redirect_edge_var_map_add (e, nresult, oop, oloc);
3864 /* If we didn't find the PHI, but it's a VOP, remember to rename
3865 it later, assuming all other tests succeed. */
3866 else if (!is_gimple_reg (nresult))
3867 bitmap_set_bit (rename_virts, SSA_NAME_VERSION (nresult));
3868 /* If we didn't find the PHI, and it's a real variable, we know
3869 from the fact that OLD_BB is tree_empty_eh_handler_p that the
3870 variable is unchanged from input to the block and we can simply
3871 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
3875 = gimple_phi_arg_location (nphi, old_bb_out->dest_idx);
3876 FOR_EACH_EDGE (e, ei, old_bb->preds)
3877 redirect_edge_var_map_add (e, nresult, nop, nloc);
3881 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
3882 we don't know what values from the other edges into NEW_BB to use. */
3883 for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
3885 gimple ophi = gsi_stmt (ogsi);
3886 tree oresult = gimple_phi_result (ophi);
3887 if (!bitmap_bit_p (ophi_handled, SSA_NAME_VERSION (oresult)))
3891 /* At this point we know that the merge will succeed. Remove the PHI
3892 nodes for the virtuals that we want to rename. */
3893 if (!bitmap_empty_p (rename_virts))
3895 for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); )
3897 gimple nphi = gsi_stmt (ngsi);
3898 tree nresult = gimple_phi_result (nphi);
3899 if (bitmap_bit_p (rename_virts, SSA_NAME_VERSION (nresult)))
3901 mark_virtual_phi_result_for_renaming (nphi);
3902 remove_phi_node (&ngsi, true);
3909 /* Finally, move the edges and update the PHIs. */
3910 for (ei = ei_start (old_bb->preds); (e = ei_safe_edge (ei)); )
3911 if (e->flags & EDGE_EH)
3913 redirect_eh_edge_1 (e, new_bb, change_region);
3914 redirect_edge_succ (e, new_bb);
3915 flush_pending_stmts (e);
3920 BITMAP_FREE (ophi_handled);
3921 BITMAP_FREE (rename_virts);
3925 FOR_EACH_EDGE (e, ei, old_bb->preds)
3926 redirect_edge_var_map_clear (e);
3927 BITMAP_FREE (ophi_handled);
3928 BITMAP_FREE (rename_virts);
3932 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
3933 old region to NEW_REGION at BB. */
3936 cleanup_empty_eh_move_lp (basic_block bb, edge e_out,
3937 eh_landing_pad lp, eh_region new_region)
3939 gimple_stmt_iterator gsi;
3942 for (pp = &lp->region->landing_pads; *pp != lp; pp = &(*pp)->next_lp)
3946 lp->region = new_region;
3947 lp->next_lp = new_region->landing_pads;
3948 new_region->landing_pads = lp;
3950 /* Delete the RESX that was matched within the empty handler block. */
3951 gsi = gsi_last_bb (bb);
3952 mark_virtual_ops_for_renaming (gsi_stmt (gsi));
3953 gsi_remove (&gsi, true);
3955 /* Clean up E_OUT for the fallthru. */
3956 e_out->flags = (e_out->flags & ~EDGE_EH) | EDGE_FALLTHRU;
3957 e_out->probability = REG_BR_PROB_BASE;
3960 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
3961 unsplitting than unsplit_eh was prepared to handle, e.g. when
3962 multiple incoming edges and phis are involved. */
3965 cleanup_empty_eh_unsplit (basic_block bb, edge e_out, eh_landing_pad lp)
3967 gimple_stmt_iterator gsi;
3970 /* We really ought not have totally lost everything following
3971 a landing pad label. Given that BB is empty, there had better
3973 gcc_assert (e_out != NULL);
3975 /* The destination block must not already have a landing pad
3976 for a different region. */
3978 for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
3980 gimple stmt = gsi_stmt (gsi);
3983 if (gimple_code (stmt) != GIMPLE_LABEL)
3985 lab = gimple_label_label (stmt);
3986 lp_nr = EH_LANDING_PAD_NR (lab);
3987 if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
3991 /* Attempt to move the PHIs into the successor block. */
3992 if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, false))
3994 if (dump_file && (dump_flags & TDF_DETAILS))
3996 "Unsplit EH landing pad %d to block %i "
3997 "(via cleanup_empty_eh).\n",
3998 lp->index, e_out->dest->index);
4005 /* Return true if edge E_FIRST is part of an empty infinite loop
4006 or leads to such a loop through a series of single successor
4010 infinite_empty_loop_p (edge e_first)
4012 bool inf_loop = false;
4015 if (e_first->dest == e_first->src)
4018 e_first->src->aux = (void *) 1;
4019 for (e = e_first; single_succ_p (e->dest); e = single_succ_edge (e->dest))
4021 gimple_stmt_iterator gsi;
4027 e->dest->aux = (void *) 1;
4028 gsi = gsi_after_labels (e->dest);
4029 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
4030 gsi_next_nondebug (&gsi);
4031 if (!gsi_end_p (gsi))
4034 e_first->src->aux = NULL;
4035 for (e = e_first; e->dest->aux; e = single_succ_edge (e->dest))
4036 e->dest->aux = NULL;
4041 /* Examine the block associated with LP to determine if it's an empty
4042 handler for its EH region. If so, attempt to redirect EH edges to
4043 an outer region. Return true the CFG was updated in any way. This
4044 is similar to jump forwarding, just across EH edges. */
4047 cleanup_empty_eh (eh_landing_pad lp)
4049 basic_block bb = label_to_block (lp->post_landing_pad);
4050 gimple_stmt_iterator gsi;
4052 eh_region new_region;
4055 bool has_non_eh_pred;
4059 /* There can be zero or one edges out of BB. This is the quickest test. */
4060 switch (EDGE_COUNT (bb->succs))
4066 e_out = EDGE_SUCC (bb, 0);
4072 resx = last_stmt (bb);
4073 if (resx && is_gimple_resx (resx))
4075 if (stmt_can_throw_external (resx))
4076 optimize_clobbers (bb);
4077 else if (sink_clobbers (bb))
4081 gsi = gsi_after_labels (bb);
4083 /* Make sure to skip debug statements. */
4084 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
4085 gsi_next_nondebug (&gsi);
4087 /* If the block is totally empty, look for more unsplitting cases. */
4088 if (gsi_end_p (gsi))
4090 /* For the degenerate case of an infinite loop bail out. */
4091 if (infinite_empty_loop_p (e_out))
4094 return ret | cleanup_empty_eh_unsplit (bb, e_out, lp);
4097 /* The block should consist only of a single RESX statement, modulo a
4098 preceding call to __builtin_stack_restore if there is no outgoing
4099 edge, since the call can be eliminated in this case. */
4100 resx = gsi_stmt (gsi);
4101 if (!e_out && gimple_call_builtin_p (resx, BUILT_IN_STACK_RESTORE))
4104 resx = gsi_stmt (gsi);
4106 if (!is_gimple_resx (resx))
4108 gcc_assert (gsi_one_before_end_p (gsi));
4110 /* Determine if there are non-EH edges, or resx edges into the handler. */
4111 has_non_eh_pred = false;
4112 FOR_EACH_EDGE (e, ei, bb->preds)
4113 if (!(e->flags & EDGE_EH))
4114 has_non_eh_pred = true;
4116 /* Find the handler that's outer of the empty handler by looking at
4117 where the RESX instruction was vectored. */
4118 new_lp_nr = lookup_stmt_eh_lp (resx);
4119 new_region = get_eh_region_from_lp_number (new_lp_nr);
4121 /* If there's no destination region within the current function,
4122 redirection is trivial via removing the throwing statements from
4123 the EH region, removing the EH edges, and allowing the block
4124 to go unreachable. */
4125 if (new_region == NULL)
4127 gcc_assert (e_out == NULL);
4128 for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
4129 if (e->flags & EDGE_EH)
4131 gimple stmt = last_stmt (e->src);
4132 remove_stmt_from_eh_lp (stmt);
4140 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4141 to handle the abort and allow the blocks to go unreachable. */
4142 if (new_region->type == ERT_MUST_NOT_THROW)
4144 for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
4145 if (e->flags & EDGE_EH)
4147 gimple stmt = last_stmt (e->src);
4148 remove_stmt_from_eh_lp (stmt);
4149 add_stmt_to_eh_lp (stmt, new_lp_nr);
4157 /* Try to redirect the EH edges and merge the PHIs into the destination
4158 landing pad block. If the merge succeeds, we'll already have redirected
4159 all the EH edges. The handler itself will go unreachable if there were
4161 if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, true))
4164 /* Finally, if all input edges are EH edges, then we can (potentially)
4165 reduce the number of transfers from the runtime by moving the landing
4166 pad from the original region to the new region. This is a win when
4167 we remove the last CLEANUP region along a particular exception
4168 propagation path. Since nothing changes except for the region with
4169 which the landing pad is associated, the PHI nodes do not need to be
4171 if (!has_non_eh_pred)
4173 cleanup_empty_eh_move_lp (bb, e_out, lp, new_region);
4174 if (dump_file && (dump_flags & TDF_DETAILS))
4175 fprintf (dump_file, "Empty EH handler %i moved to EH region %i.\n",
4176 lp->index, new_region->index);
4178 /* ??? The CFG didn't change, but we may have rendered the
4179 old EH region unreachable. Trigger a cleanup there. */
4186 if (dump_file && (dump_flags & TDF_DETAILS))
4187 fprintf (dump_file, "Empty EH handler %i removed.\n", lp->index);
4188 remove_eh_landing_pad (lp);
4192 /* Do a post-order traversal of the EH region tree. Examine each
4193 post_landing_pad block and see if we can eliminate it as empty. */
4196 cleanup_all_empty_eh (void)
4198 bool changed = false;
4202 for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
4204 changed |= cleanup_empty_eh (lp);
4209 /* Perform cleanups and lowering of exception handling
4210 1) cleanups regions with handlers doing nothing are optimized out
4211 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4212 3) Info about regions that are containing instructions, and regions
4213 reachable via local EH edges is collected
4214 4) Eh tree is pruned for regions no longer neccesary.
4216 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4217 Unify those that have the same failure decl and locus.
4221 execute_cleanup_eh_1 (void)
4223 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4224 looking up unreachable landing pads. */
4225 remove_unreachable_handlers ();
4227 /* Watch out for the region tree vanishing due to all unreachable. */
4228 if (cfun->eh->region_tree && optimize)
4230 bool changed = false;
4232 changed |= unsplit_all_eh ();
4233 changed |= cleanup_all_empty_eh ();
4237 free_dominance_info (CDI_DOMINATORS);
4238 free_dominance_info (CDI_POST_DOMINATORS);
4240 /* We delayed all basic block deletion, as we may have performed
4241 cleanups on EH edges while non-EH edges were still present. */
4242 delete_unreachable_blocks ();
4244 /* We manipulated the landing pads. Remove any region that no
4245 longer has a landing pad. */
4246 remove_unreachable_handlers_no_lp ();
4248 return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals;
4256 execute_cleanup_eh (void)
4258 int ret = execute_cleanup_eh_1 ();
4260 /* If the function no longer needs an EH personality routine
4261 clear it. This exposes cross-language inlining opportunities
4262 and avoids references to a never defined personality routine. */
4263 if (DECL_FUNCTION_PERSONALITY (current_function_decl)
4264 && function_needs_eh_personality (cfun) != eh_personality_lang)
4265 DECL_FUNCTION_PERSONALITY (current_function_decl) = NULL_TREE;
4271 gate_cleanup_eh (void)
4273 return cfun->eh != NULL && cfun->eh->region_tree != NULL;
4276 struct gimple_opt_pass pass_cleanup_eh = {
4279 "ehcleanup", /* name */
4280 gate_cleanup_eh, /* gate */
4281 execute_cleanup_eh, /* execute */
4284 0, /* static_pass_number */
4285 TV_TREE_EH, /* tv_id */
4286 PROP_gimple_lcf, /* properties_required */
4287 0, /* properties_provided */
4288 0, /* properties_destroyed */
4289 0, /* todo_flags_start */
4290 0 /* todo_flags_finish */
4294 /* Verify that BB containing STMT as the last statement, has precisely the
4295 edge that make_eh_edges would create. */
4298 verify_eh_edges (gimple stmt)
4300 basic_block bb = gimple_bb (stmt);
4301 eh_landing_pad lp = NULL;
4306 lp_nr = lookup_stmt_eh_lp (stmt);
4308 lp = get_eh_landing_pad_from_number (lp_nr);
4311 FOR_EACH_EDGE (e, ei, bb->succs)
4313 if (e->flags & EDGE_EH)
4317 error ("BB %i has multiple EH edges", bb->index);
4329 error ("BB %i can not throw but has an EH edge", bb->index);
4335 if (!stmt_could_throw_p (stmt))
4337 error ("BB %i last statement has incorrectly set lp", bb->index);
4341 if (eh_edge == NULL)
4343 error ("BB %i is missing an EH edge", bb->index);
4347 if (eh_edge->dest != label_to_block (lp->post_landing_pad))
4349 error ("Incorrect EH edge %i->%i", bb->index, eh_edge->dest->index);
4356 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4359 verify_eh_dispatch_edge (gimple stmt)
4363 basic_block src, dst;
4364 bool want_fallthru = true;
4368 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
4369 src = gimple_bb (stmt);
4371 FOR_EACH_EDGE (e, ei, src->succs)
4372 gcc_assert (e->aux == NULL);
4377 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
4379 dst = label_to_block (c->label);
4380 e = find_edge (src, dst);
4383 error ("BB %i is missing an edge", src->index);
4388 /* A catch-all handler doesn't have a fallthru. */
4389 if (c->type_list == NULL)
4391 want_fallthru = false;
4397 case ERT_ALLOWED_EXCEPTIONS:
4398 dst = label_to_block (r->u.allowed.label);
4399 e = find_edge (src, dst);
4402 error ("BB %i is missing an edge", src->index);
4413 FOR_EACH_EDGE (e, ei, src->succs)
4415 if (e->flags & EDGE_FALLTHRU)
4417 if (fall_edge != NULL)
4419 error ("BB %i too many fallthru edges", src->index);
4428 error ("BB %i has incorrect edge", src->index);
4432 if ((fall_edge != NULL) ^ want_fallthru)
4434 error ("BB %i has incorrect fallthru edge", src->index);