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"
43 /* In some instances a tree and a gimple need to be stored in a same table,
44 i.e. in hash tables. This is a structure to do this. */
45 typedef union {tree *tp; tree t; gimple g;} treemple;
47 /* Nonzero if we are using EH to handle cleanups. */
48 static int using_eh_for_cleanups_p = 0;
51 using_eh_for_cleanups (void)
53 using_eh_for_cleanups_p = 1;
56 /* Misc functions used in this file. */
58 /* Remember and lookup EH landing pad data for arbitrary statements.
59 Really this means any statement that could_throw_p. We could
60 stuff this information into the stmt_ann data structure, but:
62 (1) We absolutely rely on this information being kept until
63 we get to rtl. Once we're done with lowering here, if we lose
64 the information there's no way to recover it!
66 (2) There are many more statements that *cannot* throw as
67 compared to those that can. We should be saving some amount
68 of space by only allocating memory for those that can throw. */
70 /* Add statement T in function IFUN to landing pad NUM. */
73 add_stmt_to_eh_lp_fn (struct function *ifun, gimple t, int num)
75 struct throw_stmt_node *n;
78 gcc_assert (num != 0);
80 n = ggc_alloc_throw_stmt_node ();
84 if (!get_eh_throw_stmt_table (ifun))
85 set_eh_throw_stmt_table (ifun, htab_create_ggc (31, struct_ptr_hash,
89 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), n, INSERT);
94 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
97 add_stmt_to_eh_lp (gimple t, int num)
99 add_stmt_to_eh_lp_fn (cfun, t, num);
102 /* Add statement T to the single EH landing pad in REGION. */
105 record_stmt_eh_region (eh_region region, gimple t)
109 if (region->type == ERT_MUST_NOT_THROW)
110 add_stmt_to_eh_lp_fn (cfun, t, -region->index);
113 eh_landing_pad lp = region->landing_pads;
115 lp = gen_eh_landing_pad (region);
117 gcc_assert (lp->next_lp == NULL);
118 add_stmt_to_eh_lp_fn (cfun, t, lp->index);
123 /* Remove statement T in function IFUN from its EH landing pad. */
126 remove_stmt_from_eh_lp_fn (struct function *ifun, gimple t)
128 struct throw_stmt_node dummy;
131 if (!get_eh_throw_stmt_table (ifun))
135 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), &dummy,
139 htab_clear_slot (get_eh_throw_stmt_table (ifun), slot);
147 /* Remove statement T in the current function (cfun) from its
151 remove_stmt_from_eh_lp (gimple t)
153 return remove_stmt_from_eh_lp_fn (cfun, t);
156 /* Determine if statement T is inside an EH region in function IFUN.
157 Positive numbers indicate a landing pad index; negative numbers
158 indicate a MUST_NOT_THROW region index; zero indicates that the
159 statement is not recorded in the region table. */
162 lookup_stmt_eh_lp_fn (struct function *ifun, gimple t)
164 struct throw_stmt_node *p, n;
166 if (ifun->eh->throw_stmt_table == NULL)
170 p = (struct throw_stmt_node *) htab_find (ifun->eh->throw_stmt_table, &n);
171 return p ? p->lp_nr : 0;
174 /* Likewise, but always use the current function. */
177 lookup_stmt_eh_lp (gimple t)
179 /* We can get called from initialized data when -fnon-call-exceptions
180 is on; prevent crash. */
183 return lookup_stmt_eh_lp_fn (cfun, t);
186 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
187 nodes and LABEL_DECL nodes. We will use this during the second phase to
188 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
190 struct finally_tree_node
192 /* When storing a GIMPLE_TRY, we have to record a gimple. However
193 when deciding whether a GOTO to a certain LABEL_DECL (which is a
194 tree) leaves the TRY block, its necessary to record a tree in
195 this field. Thus a treemple is used. */
200 /* Note that this table is *not* marked GTY. It is short-lived. */
201 static htab_t finally_tree;
204 record_in_finally_tree (treemple child, gimple parent)
206 struct finally_tree_node *n;
209 n = XNEW (struct finally_tree_node);
213 slot = htab_find_slot (finally_tree, n, INSERT);
219 collect_finally_tree (gimple stmt, gimple region);
221 /* Go through the gimple sequence. Works with collect_finally_tree to
222 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
225 collect_finally_tree_1 (gimple_seq seq, gimple region)
227 gimple_stmt_iterator gsi;
229 for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi))
230 collect_finally_tree (gsi_stmt (gsi), region);
234 collect_finally_tree (gimple stmt, gimple region)
238 switch (gimple_code (stmt))
241 temp.t = gimple_label_label (stmt);
242 record_in_finally_tree (temp, region);
246 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
249 record_in_finally_tree (temp, region);
250 collect_finally_tree_1 (gimple_try_eval (stmt), stmt);
251 collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
253 else if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH)
255 collect_finally_tree_1 (gimple_try_eval (stmt), region);
256 collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
261 collect_finally_tree_1 (gimple_catch_handler (stmt), region);
264 case GIMPLE_EH_FILTER:
265 collect_finally_tree_1 (gimple_eh_filter_failure (stmt), region);
269 collect_finally_tree_1 (gimple_eh_else_n_body (stmt), region);
270 collect_finally_tree_1 (gimple_eh_else_e_body (stmt), region);
274 /* A type, a decl, or some kind of statement that we're not
275 interested in. Don't walk them. */
281 /* Use the finally tree to determine if a jump from START to TARGET
282 would leave the try_finally node that START lives in. */
285 outside_finally_tree (treemple start, gimple target)
287 struct finally_tree_node n, *p;
292 p = (struct finally_tree_node *) htab_find (finally_tree, &n);
297 while (start.g != target);
302 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
303 nodes into a set of gotos, magic labels, and eh regions.
304 The eh region creation is straight-forward, but frobbing all the gotos
305 and such into shape isn't. */
307 /* The sequence into which we record all EH stuff. This will be
308 placed at the end of the function when we're all done. */
309 static gimple_seq eh_seq;
311 /* Record whether an EH region contains something that can throw,
312 indexed by EH region number. */
313 static bitmap eh_region_may_contain_throw_map;
315 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
316 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
317 The idea is to record a gimple statement for everything except for
318 the conditionals, which get their labels recorded. Since labels are
319 of type 'tree', we need this node to store both gimple and tree
320 objects. REPL_STMT is the sequence used to replace the goto/return
321 statement. CONT_STMT is used to store the statement that allows
322 the return/goto to jump to the original destination. */
324 struct goto_queue_node
327 gimple_seq repl_stmt;
330 /* This is used when index >= 0 to indicate that stmt is a label (as
331 opposed to a goto stmt). */
335 /* State of the world while lowering. */
339 /* What's "current" while constructing the eh region tree. These
340 correspond to variables of the same name in cfun->eh, which we
341 don't have easy access to. */
342 eh_region cur_region;
344 /* What's "current" for the purposes of __builtin_eh_pointer. For
345 a CATCH, this is the associated TRY. For an EH_FILTER, this is
346 the associated ALLOWED_EXCEPTIONS, etc. */
347 eh_region ehp_region;
349 /* Processing of TRY_FINALLY requires a bit more state. This is
350 split out into a separate structure so that we don't have to
351 copy so much when processing other nodes. */
352 struct leh_tf_state *tf;
357 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
358 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
359 this so that outside_finally_tree can reliably reference the tree used
360 in the collect_finally_tree data structures. */
361 gimple try_finally_expr;
364 /* While lowering a top_p usually it is expanded into multiple statements,
365 thus we need the following field to store them. */
366 gimple_seq top_p_seq;
368 /* The state outside this try_finally node. */
369 struct leh_state *outer;
371 /* The exception region created for it. */
374 /* The goto queue. */
375 struct goto_queue_node *goto_queue;
376 size_t goto_queue_size;
377 size_t goto_queue_active;
379 /* Pointer map to help in searching goto_queue when it is large. */
380 struct pointer_map_t *goto_queue_map;
382 /* The set of unique labels seen as entries in the goto queue. */
383 VEC(tree,heap) *dest_array;
385 /* A label to be added at the end of the completed transformed
386 sequence. It will be set if may_fallthru was true *at one time*,
387 though subsequent transformations may have cleared that flag. */
390 /* True if it is possible to fall out the bottom of the try block.
391 Cleared if the fallthru is converted to a goto. */
394 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
397 /* True if the finally block can receive an exception edge.
398 Cleared if the exception case is handled by code duplication. */
402 static gimple_seq lower_eh_must_not_throw (struct leh_state *, gimple);
404 /* Search for STMT in the goto queue. Return the replacement,
405 or null if the statement isn't in the queue. */
407 #define LARGE_GOTO_QUEUE 20
409 static void lower_eh_constructs_1 (struct leh_state *state, gimple_seq *seq);
412 find_goto_replacement (struct leh_tf_state *tf, treemple stmt)
417 if (tf->goto_queue_active < LARGE_GOTO_QUEUE)
419 for (i = 0; i < tf->goto_queue_active; i++)
420 if ( tf->goto_queue[i].stmt.g == stmt.g)
421 return tf->goto_queue[i].repl_stmt;
425 /* If we have a large number of entries in the goto_queue, create a
426 pointer map and use that for searching. */
428 if (!tf->goto_queue_map)
430 tf->goto_queue_map = pointer_map_create ();
431 for (i = 0; i < tf->goto_queue_active; i++)
433 slot = pointer_map_insert (tf->goto_queue_map,
434 tf->goto_queue[i].stmt.g);
435 gcc_assert (*slot == NULL);
436 *slot = &tf->goto_queue[i];
440 slot = pointer_map_contains (tf->goto_queue_map, stmt.g);
442 return (((struct goto_queue_node *) *slot)->repl_stmt);
447 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
448 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
449 then we can just splat it in, otherwise we add the new stmts immediately
450 after the GIMPLE_COND and redirect. */
453 replace_goto_queue_cond_clause (tree *tp, struct leh_tf_state *tf,
454 gimple_stmt_iterator *gsi)
459 location_t loc = gimple_location (gsi_stmt (*gsi));
462 new_seq = find_goto_replacement (tf, temp);
466 if (gimple_seq_singleton_p (new_seq)
467 && gimple_code (gimple_seq_first_stmt (new_seq)) == GIMPLE_GOTO)
469 *tp = gimple_goto_dest (gimple_seq_first_stmt (new_seq));
473 label = create_artificial_label (loc);
474 /* Set the new label for the GIMPLE_COND */
477 gsi_insert_after (gsi, gimple_build_label (label), GSI_CONTINUE_LINKING);
478 gsi_insert_seq_after (gsi, gimple_seq_copy (new_seq), GSI_CONTINUE_LINKING);
481 /* The real work of replace_goto_queue. Returns with TSI updated to
482 point to the next statement. */
484 static void replace_goto_queue_stmt_list (gimple_seq *, struct leh_tf_state *);
487 replace_goto_queue_1 (gimple stmt, struct leh_tf_state *tf,
488 gimple_stmt_iterator *gsi)
494 switch (gimple_code (stmt))
499 seq = find_goto_replacement (tf, temp);
502 gsi_insert_seq_before (gsi, gimple_seq_copy (seq), GSI_SAME_STMT);
503 gsi_remove (gsi, false);
509 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 2), tf, gsi);
510 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 3), tf, gsi);
514 replace_goto_queue_stmt_list (gimple_try_eval_ptr (stmt), tf);
515 replace_goto_queue_stmt_list (gimple_try_cleanup_ptr (stmt), tf);
518 replace_goto_queue_stmt_list (gimple_catch_handler_ptr (stmt), tf);
520 case GIMPLE_EH_FILTER:
521 replace_goto_queue_stmt_list (gimple_eh_filter_failure_ptr (stmt), tf);
524 replace_goto_queue_stmt_list (gimple_eh_else_n_body_ptr (stmt), tf);
525 replace_goto_queue_stmt_list (gimple_eh_else_e_body_ptr (stmt), tf);
529 /* These won't have gotos in them. */
536 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
539 replace_goto_queue_stmt_list (gimple_seq *seq, struct leh_tf_state *tf)
541 gimple_stmt_iterator gsi = gsi_start (*seq);
543 while (!gsi_end_p (gsi))
544 replace_goto_queue_1 (gsi_stmt (gsi), tf, &gsi);
547 /* Replace all goto queue members. */
550 replace_goto_queue (struct leh_tf_state *tf)
552 if (tf->goto_queue_active == 0)
554 replace_goto_queue_stmt_list (&tf->top_p_seq, tf);
555 replace_goto_queue_stmt_list (&eh_seq, tf);
558 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
559 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
563 record_in_goto_queue (struct leh_tf_state *tf,
569 struct goto_queue_node *q;
571 gcc_assert (!tf->goto_queue_map);
573 active = tf->goto_queue_active;
574 size = tf->goto_queue_size;
577 size = (size ? size * 2 : 32);
578 tf->goto_queue_size = size;
580 = XRESIZEVEC (struct goto_queue_node, tf->goto_queue, size);
583 q = &tf->goto_queue[active];
584 tf->goto_queue_active = active + 1;
586 memset (q, 0, sizeof (*q));
589 q->is_label = is_label;
592 /* Record the LABEL label in the goto queue contained in TF.
596 record_in_goto_queue_label (struct leh_tf_state *tf, treemple stmt, tree label)
599 treemple temp, new_stmt;
604 /* Computed and non-local gotos do not get processed. Given
605 their nature we can neither tell whether we've escaped the
606 finally block nor redirect them if we knew. */
607 if (TREE_CODE (label) != LABEL_DECL)
610 /* No need to record gotos that don't leave the try block. */
612 if (!outside_finally_tree (temp, tf->try_finally_expr))
615 if (! tf->dest_array)
617 tf->dest_array = VEC_alloc (tree, heap, 10);
618 VEC_quick_push (tree, tf->dest_array, label);
623 int n = VEC_length (tree, tf->dest_array);
624 for (index = 0; index < n; ++index)
625 if (VEC_index (tree, tf->dest_array, index) == label)
628 VEC_safe_push (tree, heap, tf->dest_array, label);
631 /* In the case of a GOTO we want to record the destination label,
632 since with a GIMPLE_COND we have an easy access to the then/else
635 record_in_goto_queue (tf, new_stmt, index, true);
638 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
639 node, and if so record that fact in the goto queue associated with that
643 maybe_record_in_goto_queue (struct leh_state *state, gimple stmt)
645 struct leh_tf_state *tf = state->tf;
651 switch (gimple_code (stmt))
654 new_stmt.tp = gimple_op_ptr (stmt, 2);
655 record_in_goto_queue_label (tf, new_stmt, gimple_cond_true_label (stmt));
656 new_stmt.tp = gimple_op_ptr (stmt, 3);
657 record_in_goto_queue_label (tf, new_stmt, gimple_cond_false_label (stmt));
661 record_in_goto_queue_label (tf, new_stmt, gimple_goto_dest (stmt));
665 tf->may_return = true;
667 record_in_goto_queue (tf, new_stmt, -1, false);
676 #ifdef ENABLE_CHECKING
677 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
678 was in fact structured, and we've not yet done jump threading, then none
679 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
682 verify_norecord_switch_expr (struct leh_state *state, gimple switch_expr)
684 struct leh_tf_state *tf = state->tf;
690 n = gimple_switch_num_labels (switch_expr);
692 for (i = 0; i < n; ++i)
695 tree lab = CASE_LABEL (gimple_switch_label (switch_expr, i));
697 gcc_assert (!outside_finally_tree (temp, tf->try_finally_expr));
701 #define verify_norecord_switch_expr(state, switch_expr)
704 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
705 non-null, insert it before the new branch. */
708 do_return_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod)
712 /* In the case of a return, the queue node must be a gimple statement. */
713 gcc_assert (!q->is_label);
715 /* Note that the return value may have already been computed, e.g.,
728 should return 0, not 1. We don't have to do anything to make
729 this happens because the return value has been placed in the
730 RESULT_DECL already. */
732 q->cont_stmt = q->stmt.g;
735 gimple_seq_add_seq (&q->repl_stmt, mod);
737 x = gimple_build_goto (finlab);
738 gimple_seq_add_stmt (&q->repl_stmt, x);
741 /* Similar, but easier, for GIMPLE_GOTO. */
744 do_goto_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod,
745 struct leh_tf_state *tf)
749 gcc_assert (q->is_label);
751 q->cont_stmt = gimple_build_goto (VEC_index (tree, tf->dest_array, q->index));
754 gimple_seq_add_seq (&q->repl_stmt, mod);
756 x = gimple_build_goto (finlab);
757 gimple_seq_add_stmt (&q->repl_stmt, x);
760 /* Emit a standard landing pad sequence into SEQ for REGION. */
763 emit_post_landing_pad (gimple_seq *seq, eh_region region)
765 eh_landing_pad lp = region->landing_pads;
769 lp = gen_eh_landing_pad (region);
771 lp->post_landing_pad = create_artificial_label (UNKNOWN_LOCATION);
772 EH_LANDING_PAD_NR (lp->post_landing_pad) = lp->index;
774 x = gimple_build_label (lp->post_landing_pad);
775 gimple_seq_add_stmt (seq, x);
778 /* Emit a RESX statement into SEQ for REGION. */
781 emit_resx (gimple_seq *seq, eh_region region)
783 gimple x = gimple_build_resx (region->index);
784 gimple_seq_add_stmt (seq, x);
786 record_stmt_eh_region (region->outer, x);
789 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
792 emit_eh_dispatch (gimple_seq *seq, eh_region region)
794 gimple x = gimple_build_eh_dispatch (region->index);
795 gimple_seq_add_stmt (seq, x);
798 /* Note that the current EH region may contain a throw, or a
799 call to a function which itself may contain a throw. */
802 note_eh_region_may_contain_throw (eh_region region)
804 while (bitmap_set_bit (eh_region_may_contain_throw_map, region->index))
806 if (region->type == ERT_MUST_NOT_THROW)
808 region = region->outer;
814 /* Check if REGION has been marked as containing a throw. If REGION is
815 NULL, this predicate is false. */
818 eh_region_may_contain_throw (eh_region r)
820 return r && bitmap_bit_p (eh_region_may_contain_throw_map, r->index);
823 /* We want to transform
824 try { body; } catch { stuff; }
834 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
835 should be placed before the second operand, or NULL. OVER is
836 an existing label that should be put at the exit, or NULL. */
839 frob_into_branch_around (gimple tp, eh_region region, tree over)
842 gimple_seq cleanup, result;
843 location_t loc = gimple_location (tp);
845 cleanup = gimple_try_cleanup (tp);
846 result = gimple_try_eval (tp);
849 emit_post_landing_pad (&eh_seq, region);
851 if (gimple_seq_may_fallthru (cleanup))
854 over = create_artificial_label (loc);
855 x = gimple_build_goto (over);
856 gimple_seq_add_stmt (&cleanup, x);
858 gimple_seq_add_seq (&eh_seq, cleanup);
862 x = gimple_build_label (over);
863 gimple_seq_add_stmt (&result, x);
868 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
869 Make sure to record all new labels found. */
872 lower_try_finally_dup_block (gimple_seq seq, struct leh_state *outer_state)
874 gimple region = NULL;
877 new_seq = copy_gimple_seq_and_replace_locals (seq);
880 region = outer_state->tf->try_finally_expr;
881 collect_finally_tree_1 (new_seq, region);
886 /* A subroutine of lower_try_finally. Create a fallthru label for
887 the given try_finally state. The only tricky bit here is that
888 we have to make sure to record the label in our outer context. */
891 lower_try_finally_fallthru_label (struct leh_tf_state *tf)
893 tree label = tf->fallthru_label;
898 label = create_artificial_label (gimple_location (tf->try_finally_expr));
899 tf->fallthru_label = label;
903 record_in_finally_tree (temp, tf->outer->tf->try_finally_expr);
909 /* A subroutine of lower_try_finally. If FINALLY consits of a
910 GIMPLE_EH_ELSE node, return it. */
913 get_eh_else (gimple_seq finally)
915 gimple x = gimple_seq_first_stmt (finally);
916 if (gimple_code (x) == GIMPLE_EH_ELSE)
918 gcc_assert (gimple_seq_singleton_p (finally));
924 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
925 langhook returns non-null, then the language requires that the exception
926 path out of a try_finally be treated specially. To wit: the code within
927 the finally block may not itself throw an exception. We have two choices
928 here. First we can duplicate the finally block and wrap it in a
929 must_not_throw region. Second, we can generate code like
934 if (fintmp == eh_edge)
935 protect_cleanup_actions;
938 where "fintmp" is the temporary used in the switch statement generation
939 alternative considered below. For the nonce, we always choose the first
942 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
945 honor_protect_cleanup_actions (struct leh_state *outer_state,
946 struct leh_state *this_state,
947 struct leh_tf_state *tf)
949 tree protect_cleanup_actions;
950 gimple_stmt_iterator gsi;
951 bool finally_may_fallthru;
955 /* First check for nothing to do. */
956 if (lang_hooks.eh_protect_cleanup_actions == NULL)
958 protect_cleanup_actions = lang_hooks.eh_protect_cleanup_actions ();
959 if (protect_cleanup_actions == NULL)
962 finally = gimple_try_cleanup (tf->top_p);
963 eh_else = get_eh_else (finally);
965 /* Duplicate the FINALLY block. Only need to do this for try-finally,
966 and not for cleanups. If we've got an EH_ELSE, extract it now. */
969 finally = gimple_eh_else_e_body (eh_else);
970 gimple_try_set_cleanup (tf->top_p, gimple_eh_else_n_body (eh_else));
973 finally = lower_try_finally_dup_block (finally, outer_state);
974 finally_may_fallthru = gimple_seq_may_fallthru (finally);
976 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
977 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
978 to be in an enclosing scope, but needs to be implemented at this level
979 to avoid a nesting violation (see wrap_temporary_cleanups in
980 cp/decl.c). Since it's logically at an outer level, we should call
981 terminate before we get to it, so strip it away before adding the
982 MUST_NOT_THROW filter. */
983 gsi = gsi_start (finally);
985 if (gimple_code (x) == GIMPLE_TRY
986 && gimple_try_kind (x) == GIMPLE_TRY_CATCH
987 && gimple_try_catch_is_cleanup (x))
989 gsi_insert_seq_before (&gsi, gimple_try_eval (x), GSI_SAME_STMT);
990 gsi_remove (&gsi, false);
993 /* Wrap the block with protect_cleanup_actions as the action. */
994 x = gimple_build_eh_must_not_throw (protect_cleanup_actions);
995 x = gimple_build_try (finally, gimple_seq_alloc_with_stmt (x),
997 finally = lower_eh_must_not_throw (outer_state, x);
999 /* Drop all of this into the exception sequence. */
1000 emit_post_landing_pad (&eh_seq, tf->region);
1001 gimple_seq_add_seq (&eh_seq, finally);
1002 if (finally_may_fallthru)
1003 emit_resx (&eh_seq, tf->region);
1005 /* Having now been handled, EH isn't to be considered with
1006 the rest of the outgoing edges. */
1007 tf->may_throw = false;
1010 /* A subroutine of lower_try_finally. We have determined that there is
1011 no fallthru edge out of the finally block. This means that there is
1012 no outgoing edge corresponding to any incoming edge. Restructure the
1013 try_finally node for this special case. */
1016 lower_try_finally_nofallthru (struct leh_state *state,
1017 struct leh_tf_state *tf)
1022 struct goto_queue_node *q, *qe;
1024 lab = create_artificial_label (gimple_location (tf->try_finally_expr));
1026 /* We expect that tf->top_p is a GIMPLE_TRY. */
1027 finally = gimple_try_cleanup (tf->top_p);
1028 tf->top_p_seq = gimple_try_eval (tf->top_p);
1030 x = gimple_build_label (lab);
1031 gimple_seq_add_stmt (&tf->top_p_seq, x);
1034 qe = q + tf->goto_queue_active;
1037 do_return_redirection (q, lab, NULL);
1039 do_goto_redirection (q, lab, NULL, tf);
1041 replace_goto_queue (tf);
1043 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1044 eh_else = get_eh_else (finally);
1047 finally = gimple_eh_else_n_body (eh_else);
1048 lower_eh_constructs_1 (state, &finally);
1049 gimple_seq_add_seq (&tf->top_p_seq, finally);
1053 finally = gimple_eh_else_e_body (eh_else);
1054 lower_eh_constructs_1 (state, &finally);
1056 emit_post_landing_pad (&eh_seq, tf->region);
1057 gimple_seq_add_seq (&eh_seq, finally);
1062 lower_eh_constructs_1 (state, &finally);
1063 gimple_seq_add_seq (&tf->top_p_seq, finally);
1067 emit_post_landing_pad (&eh_seq, tf->region);
1069 x = gimple_build_goto (lab);
1070 gimple_seq_add_stmt (&eh_seq, x);
1075 /* A subroutine of lower_try_finally. We have determined that there is
1076 exactly one destination of the finally block. Restructure the
1077 try_finally node for this special case. */
1080 lower_try_finally_onedest (struct leh_state *state, struct leh_tf_state *tf)
1082 struct goto_queue_node *q, *qe;
1086 location_t loc = gimple_location (tf->try_finally_expr);
1088 finally = gimple_try_cleanup (tf->top_p);
1089 tf->top_p_seq = gimple_try_eval (tf->top_p);
1091 /* Since there's only one destination, and the destination edge can only
1092 either be EH or non-EH, that implies that all of our incoming edges
1093 are of the same type. Therefore we can lower EH_ELSE immediately. */
1094 x = get_eh_else (finally);
1098 finally = gimple_eh_else_e_body (x);
1100 finally = gimple_eh_else_n_body (x);
1103 lower_eh_constructs_1 (state, &finally);
1107 /* Only reachable via the exception edge. Add the given label to
1108 the head of the FINALLY block. Append a RESX at the end. */
1109 emit_post_landing_pad (&eh_seq, tf->region);
1110 gimple_seq_add_seq (&eh_seq, finally);
1111 emit_resx (&eh_seq, tf->region);
1115 if (tf->may_fallthru)
1117 /* Only reachable via the fallthru edge. Do nothing but let
1118 the two blocks run together; we'll fall out the bottom. */
1119 gimple_seq_add_seq (&tf->top_p_seq, finally);
1123 finally_label = create_artificial_label (loc);
1124 x = gimple_build_label (finally_label);
1125 gimple_seq_add_stmt (&tf->top_p_seq, x);
1127 gimple_seq_add_seq (&tf->top_p_seq, finally);
1130 qe = q + tf->goto_queue_active;
1134 /* Reachable by return expressions only. Redirect them. */
1136 do_return_redirection (q, finally_label, NULL);
1137 replace_goto_queue (tf);
1141 /* Reachable by goto expressions only. Redirect them. */
1143 do_goto_redirection (q, finally_label, NULL, tf);
1144 replace_goto_queue (tf);
1146 if (VEC_index (tree, tf->dest_array, 0) == tf->fallthru_label)
1148 /* Reachable by goto to fallthru label only. Redirect it
1149 to the new label (already created, sadly), and do not
1150 emit the final branch out, or the fallthru label. */
1151 tf->fallthru_label = NULL;
1156 /* Place the original return/goto to the original destination
1157 immediately after the finally block. */
1158 x = tf->goto_queue[0].cont_stmt;
1159 gimple_seq_add_stmt (&tf->top_p_seq, x);
1160 maybe_record_in_goto_queue (state, x);
1163 /* A subroutine of lower_try_finally. There are multiple edges incoming
1164 and outgoing from the finally block. Implement this by duplicating the
1165 finally block for every destination. */
1168 lower_try_finally_copy (struct leh_state *state, struct leh_tf_state *tf)
1171 gimple_seq new_stmt;
1175 location_t tf_loc = gimple_location (tf->try_finally_expr);
1177 finally = gimple_try_cleanup (tf->top_p);
1179 /* Notice EH_ELSE, and simplify some of the remaining code
1180 by considering FINALLY to be the normal return path only. */
1181 eh_else = get_eh_else (finally);
1183 finally = gimple_eh_else_n_body (eh_else);
1185 tf->top_p_seq = gimple_try_eval (tf->top_p);
1188 if (tf->may_fallthru)
1190 seq = lower_try_finally_dup_block (finally, state);
1191 lower_eh_constructs_1 (state, &seq);
1192 gimple_seq_add_seq (&new_stmt, seq);
1194 tmp = lower_try_finally_fallthru_label (tf);
1195 x = gimple_build_goto (tmp);
1196 gimple_seq_add_stmt (&new_stmt, x);
1201 /* We don't need to copy the EH path of EH_ELSE,
1202 since it is only emitted once. */
1204 seq = gimple_eh_else_e_body (eh_else);
1206 seq = lower_try_finally_dup_block (finally, state);
1207 lower_eh_constructs_1 (state, &seq);
1209 emit_post_landing_pad (&eh_seq, tf->region);
1210 gimple_seq_add_seq (&eh_seq, seq);
1211 emit_resx (&eh_seq, tf->region);
1216 struct goto_queue_node *q, *qe;
1217 int return_index, index;
1220 struct goto_queue_node *q;
1224 return_index = VEC_length (tree, tf->dest_array);
1225 labels = XCNEWVEC (struct labels_s, return_index + 1);
1228 qe = q + tf->goto_queue_active;
1231 index = q->index < 0 ? return_index : q->index;
1233 if (!labels[index].q)
1234 labels[index].q = q;
1237 for (index = 0; index < return_index + 1; index++)
1241 q = labels[index].q;
1245 lab = labels[index].label
1246 = create_artificial_label (tf_loc);
1248 if (index == return_index)
1249 do_return_redirection (q, lab, NULL);
1251 do_goto_redirection (q, lab, NULL, tf);
1253 x = gimple_build_label (lab);
1254 gimple_seq_add_stmt (&new_stmt, x);
1256 seq = lower_try_finally_dup_block (finally, state);
1257 lower_eh_constructs_1 (state, &seq);
1258 gimple_seq_add_seq (&new_stmt, seq);
1260 gimple_seq_add_stmt (&new_stmt, q->cont_stmt);
1261 maybe_record_in_goto_queue (state, q->cont_stmt);
1264 for (q = tf->goto_queue; q < qe; q++)
1268 index = q->index < 0 ? return_index : q->index;
1270 if (labels[index].q == q)
1273 lab = labels[index].label;
1275 if (index == return_index)
1276 do_return_redirection (q, lab, NULL);
1278 do_goto_redirection (q, lab, NULL, tf);
1281 replace_goto_queue (tf);
1285 /* Need to link new stmts after running replace_goto_queue due
1286 to not wanting to process the same goto stmts twice. */
1287 gimple_seq_add_seq (&tf->top_p_seq, new_stmt);
1290 /* A subroutine of lower_try_finally. There are multiple edges incoming
1291 and outgoing from the finally block. Implement this by instrumenting
1292 each incoming edge and creating a switch statement at the end of the
1293 finally block that branches to the appropriate destination. */
1296 lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf)
1298 struct goto_queue_node *q, *qe;
1299 tree finally_tmp, finally_label;
1300 int return_index, eh_index, fallthru_index;
1301 int nlabels, ndests, j, last_case_index;
1303 VEC (tree,heap) *case_label_vec;
1304 gimple_seq switch_body = NULL;
1309 struct pointer_map_t *cont_map = NULL;
1310 /* The location of the TRY_FINALLY stmt. */
1311 location_t tf_loc = gimple_location (tf->try_finally_expr);
1312 /* The location of the finally block. */
1313 location_t finally_loc;
1315 finally = gimple_try_cleanup (tf->top_p);
1316 eh_else = get_eh_else (finally);
1318 /* Mash the TRY block to the head of the chain. */
1319 tf->top_p_seq = gimple_try_eval (tf->top_p);
1321 /* The location of the finally is either the last stmt in the finally
1322 block or the location of the TRY_FINALLY itself. */
1323 x = gimple_seq_last_stmt (finally);
1324 finally_loc = x ? gimple_location (x) : tf_loc;
1326 /* Lower the finally block itself. */
1327 lower_eh_constructs_1 (state, &finally);
1329 /* Prepare for switch statement generation. */
1330 nlabels = VEC_length (tree, tf->dest_array);
1331 return_index = nlabels;
1332 eh_index = return_index + tf->may_return;
1333 fallthru_index = eh_index + (tf->may_throw && !eh_else);
1334 ndests = fallthru_index + tf->may_fallthru;
1336 finally_tmp = create_tmp_var (integer_type_node, "finally_tmp");
1337 finally_label = create_artificial_label (finally_loc);
1339 /* We use VEC_quick_push on case_label_vec throughout this function,
1340 since we know the size in advance and allocate precisely as muce
1342 case_label_vec = VEC_alloc (tree, heap, ndests);
1344 last_case_index = 0;
1346 /* Begin inserting code for getting to the finally block. Things
1347 are done in this order to correspond to the sequence the code is
1350 if (tf->may_fallthru)
1352 x = gimple_build_assign (finally_tmp,
1353 build_int_cst (integer_type_node,
1355 gimple_seq_add_stmt (&tf->top_p_seq, x);
1357 tmp = build_int_cst (integer_type_node, fallthru_index);
1358 last_case = build_case_label (tmp, NULL,
1359 create_artificial_label (tf_loc));
1360 VEC_quick_push (tree, case_label_vec, last_case);
1363 x = gimple_build_label (CASE_LABEL (last_case));
1364 gimple_seq_add_stmt (&switch_body, x);
1366 tmp = lower_try_finally_fallthru_label (tf);
1367 x = gimple_build_goto (tmp);
1368 gimple_seq_add_stmt (&switch_body, x);
1371 /* For EH_ELSE, emit the exception path (plus resx) now, then
1372 subsequently we only need consider the normal path. */
1377 finally = gimple_eh_else_e_body (eh_else);
1378 lower_eh_constructs_1 (state, &finally);
1380 emit_post_landing_pad (&eh_seq, tf->region);
1381 gimple_seq_add_seq (&eh_seq, finally);
1382 emit_resx (&eh_seq, tf->region);
1385 finally = gimple_eh_else_n_body (eh_else);
1387 else if (tf->may_throw)
1389 emit_post_landing_pad (&eh_seq, tf->region);
1391 x = gimple_build_assign (finally_tmp,
1392 build_int_cst (integer_type_node, eh_index));
1393 gimple_seq_add_stmt (&eh_seq, x);
1395 x = gimple_build_goto (finally_label);
1396 gimple_seq_add_stmt (&eh_seq, x);
1398 tmp = build_int_cst (integer_type_node, eh_index);
1399 last_case = build_case_label (tmp, NULL,
1400 create_artificial_label (tf_loc));
1401 VEC_quick_push (tree, case_label_vec, last_case);
1404 x = gimple_build_label (CASE_LABEL (last_case));
1405 gimple_seq_add_stmt (&eh_seq, x);
1406 emit_resx (&eh_seq, tf->region);
1409 x = gimple_build_label (finally_label);
1410 gimple_seq_add_stmt (&tf->top_p_seq, x);
1412 gimple_seq_add_seq (&tf->top_p_seq, finally);
1414 /* Redirect each incoming goto edge. */
1416 qe = q + tf->goto_queue_active;
1417 j = last_case_index + tf->may_return;
1418 /* Prepare the assignments to finally_tmp that are executed upon the
1419 entrance through a particular edge. */
1422 gimple_seq mod = NULL;
1424 unsigned int case_index;
1428 x = gimple_build_assign (finally_tmp,
1429 build_int_cst (integer_type_node,
1431 gimple_seq_add_stmt (&mod, x);
1432 do_return_redirection (q, finally_label, mod);
1433 switch_id = return_index;
1437 x = gimple_build_assign (finally_tmp,
1438 build_int_cst (integer_type_node, q->index));
1439 gimple_seq_add_stmt (&mod, x);
1440 do_goto_redirection (q, finally_label, mod, tf);
1441 switch_id = q->index;
1444 case_index = j + q->index;
1445 if (VEC_length (tree, case_label_vec) <= case_index
1446 || !VEC_index (tree, case_label_vec, case_index))
1450 tmp = build_int_cst (integer_type_node, switch_id);
1451 case_lab = build_case_label (tmp, NULL,
1452 create_artificial_label (tf_loc));
1453 /* We store the cont_stmt in the pointer map, so that we can recover
1454 it in the loop below. */
1456 cont_map = pointer_map_create ();
1457 slot = pointer_map_insert (cont_map, case_lab);
1458 *slot = q->cont_stmt;
1459 VEC_quick_push (tree, case_label_vec, case_lab);
1462 for (j = last_case_index; j < last_case_index + nlabels; j++)
1467 last_case = VEC_index (tree, case_label_vec, j);
1469 gcc_assert (last_case);
1470 gcc_assert (cont_map);
1472 slot = pointer_map_contains (cont_map, last_case);
1474 cont_stmt = *(gimple *) slot;
1476 x = gimple_build_label (CASE_LABEL (last_case));
1477 gimple_seq_add_stmt (&switch_body, x);
1478 gimple_seq_add_stmt (&switch_body, cont_stmt);
1479 maybe_record_in_goto_queue (state, cont_stmt);
1482 pointer_map_destroy (cont_map);
1484 replace_goto_queue (tf);
1486 /* Make sure that the last case is the default label, as one is required.
1487 Then sort the labels, which is also required in GIMPLE. */
1488 CASE_LOW (last_case) = NULL;
1489 sort_case_labels (case_label_vec);
1491 /* Build the switch statement, setting last_case to be the default
1493 switch_stmt = gimple_build_switch_vec (finally_tmp, last_case,
1495 gimple_set_location (switch_stmt, finally_loc);
1497 /* Need to link SWITCH_STMT after running replace_goto_queue
1498 due to not wanting to process the same goto stmts twice. */
1499 gimple_seq_add_stmt (&tf->top_p_seq, switch_stmt);
1500 gimple_seq_add_seq (&tf->top_p_seq, switch_body);
1503 /* Decide whether or not we are going to duplicate the finally block.
1504 There are several considerations.
1506 First, if this is Java, then the finally block contains code
1507 written by the user. It has line numbers associated with it,
1508 so duplicating the block means it's difficult to set a breakpoint.
1509 Since controlling code generation via -g is verboten, we simply
1510 never duplicate code without optimization.
1512 Second, we'd like to prevent egregious code growth. One way to
1513 do this is to estimate the size of the finally block, multiply
1514 that by the number of copies we'd need to make, and compare against
1515 the estimate of the size of the switch machinery we'd have to add. */
1518 decide_copy_try_finally (int ndests, bool may_throw, gimple_seq finally)
1520 int f_estimate, sw_estimate;
1523 /* If there's an EH_ELSE involved, the exception path is separate
1524 and really doesn't come into play for this computation. */
1525 eh_else = get_eh_else (finally);
1528 ndests -= may_throw;
1529 finally = gimple_eh_else_n_body (eh_else);
1534 gimple_stmt_iterator gsi;
1539 for (gsi = gsi_start (finally); !gsi_end_p (gsi); gsi_next (&gsi))
1541 gimple stmt = gsi_stmt (gsi);
1542 if (!is_gimple_debug (stmt) && !gimple_clobber_p (stmt))
1548 /* Finally estimate N times, plus N gotos. */
1549 f_estimate = count_insns_seq (finally, &eni_size_weights);
1550 f_estimate = (f_estimate + 1) * ndests;
1552 /* Switch statement (cost 10), N variable assignments, N gotos. */
1553 sw_estimate = 10 + 2 * ndests;
1555 /* Optimize for size clearly wants our best guess. */
1556 if (optimize_function_for_size_p (cfun))
1557 return f_estimate < sw_estimate;
1559 /* ??? These numbers are completely made up so far. */
1561 return f_estimate < 100 || f_estimate < sw_estimate * 2;
1563 return f_estimate < 40 || f_estimate * 2 < sw_estimate * 3;
1566 /* REG is the enclosing region for a possible cleanup region, or the region
1567 itself. Returns TRUE if such a region would be unreachable.
1569 Cleanup regions within a must-not-throw region aren't actually reachable
1570 even if there are throwing stmts within them, because the personality
1571 routine will call terminate before unwinding. */
1574 cleanup_is_dead_in (eh_region reg)
1576 while (reg && reg->type == ERT_CLEANUP)
1578 return (reg && reg->type == ERT_MUST_NOT_THROW);
1581 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1582 to a sequence of labels and blocks, plus the exception region trees
1583 that record all the magic. This is complicated by the need to
1584 arrange for the FINALLY block to be executed on all exits. */
1587 lower_try_finally (struct leh_state *state, gimple tp)
1589 struct leh_tf_state this_tf;
1590 struct leh_state this_state;
1592 gimple_seq old_eh_seq;
1594 /* Process the try block. */
1596 memset (&this_tf, 0, sizeof (this_tf));
1597 this_tf.try_finally_expr = tp;
1599 this_tf.outer = state;
1600 if (using_eh_for_cleanups_p && !cleanup_is_dead_in (state->cur_region))
1602 this_tf.region = gen_eh_region_cleanup (state->cur_region);
1603 this_state.cur_region = this_tf.region;
1607 this_tf.region = NULL;
1608 this_state.cur_region = state->cur_region;
1611 this_state.ehp_region = state->ehp_region;
1612 this_state.tf = &this_tf;
1614 old_eh_seq = eh_seq;
1617 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1619 /* Determine if the try block is escaped through the bottom. */
1620 this_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
1622 /* Determine if any exceptions are possible within the try block. */
1624 this_tf.may_throw = eh_region_may_contain_throw (this_tf.region);
1625 if (this_tf.may_throw)
1626 honor_protect_cleanup_actions (state, &this_state, &this_tf);
1628 /* Determine how many edges (still) reach the finally block. Or rather,
1629 how many destinations are reached by the finally block. Use this to
1630 determine how we process the finally block itself. */
1632 ndests = VEC_length (tree, this_tf.dest_array);
1633 ndests += this_tf.may_fallthru;
1634 ndests += this_tf.may_return;
1635 ndests += this_tf.may_throw;
1637 /* If the FINALLY block is not reachable, dike it out. */
1640 gimple_seq_add_seq (&this_tf.top_p_seq, gimple_try_eval (tp));
1641 gimple_try_set_cleanup (tp, NULL);
1643 /* If the finally block doesn't fall through, then any destination
1644 we might try to impose there isn't reached either. There may be
1645 some minor amount of cleanup and redirection still needed. */
1646 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp)))
1647 lower_try_finally_nofallthru (state, &this_tf);
1649 /* We can easily special-case redirection to a single destination. */
1650 else if (ndests == 1)
1651 lower_try_finally_onedest (state, &this_tf);
1652 else if (decide_copy_try_finally (ndests, this_tf.may_throw,
1653 gimple_try_cleanup (tp)))
1654 lower_try_finally_copy (state, &this_tf);
1656 lower_try_finally_switch (state, &this_tf);
1658 /* If someone requested we add a label at the end of the transformed
1660 if (this_tf.fallthru_label)
1662 /* This must be reached only if ndests == 0. */
1663 gimple x = gimple_build_label (this_tf.fallthru_label);
1664 gimple_seq_add_stmt (&this_tf.top_p_seq, x);
1667 VEC_free (tree, heap, this_tf.dest_array);
1668 free (this_tf.goto_queue);
1669 if (this_tf.goto_queue_map)
1670 pointer_map_destroy (this_tf.goto_queue_map);
1672 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1673 If there was no old eh_seq, then the append is trivially already done. */
1677 eh_seq = old_eh_seq;
1680 gimple_seq new_eh_seq = eh_seq;
1681 eh_seq = old_eh_seq;
1682 gimple_seq_add_seq(&eh_seq, new_eh_seq);
1686 return this_tf.top_p_seq;
1689 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1690 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1691 exception region trees that records all the magic. */
1694 lower_catch (struct leh_state *state, gimple tp)
1696 eh_region try_region = NULL;
1697 struct leh_state this_state = *state;
1698 gimple_stmt_iterator gsi;
1700 gimple_seq new_seq, cleanup;
1702 location_t try_catch_loc = gimple_location (tp);
1704 if (flag_exceptions)
1706 try_region = gen_eh_region_try (state->cur_region);
1707 this_state.cur_region = try_region;
1710 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1712 if (!eh_region_may_contain_throw (try_region))
1713 return gimple_try_eval (tp);
1716 emit_eh_dispatch (&new_seq, try_region);
1717 emit_resx (&new_seq, try_region);
1719 this_state.cur_region = state->cur_region;
1720 this_state.ehp_region = try_region;
1723 cleanup = gimple_try_cleanup (tp);
1724 for (gsi = gsi_start (cleanup);
1732 gcatch = gsi_stmt (gsi);
1733 c = gen_eh_region_catch (try_region, gimple_catch_types (gcatch));
1735 handler = gimple_catch_handler (gcatch);
1736 lower_eh_constructs_1 (&this_state, &handler);
1738 c->label = create_artificial_label (UNKNOWN_LOCATION);
1739 x = gimple_build_label (c->label);
1740 gimple_seq_add_stmt (&new_seq, x);
1742 gimple_seq_add_seq (&new_seq, handler);
1744 if (gimple_seq_may_fallthru (new_seq))
1747 out_label = create_artificial_label (try_catch_loc);
1749 x = gimple_build_goto (out_label);
1750 gimple_seq_add_stmt (&new_seq, x);
1756 gimple_try_set_cleanup (tp, new_seq);
1758 return frob_into_branch_around (tp, try_region, out_label);
1761 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1762 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1763 region trees that record all the magic. */
1766 lower_eh_filter (struct leh_state *state, gimple tp)
1768 struct leh_state this_state = *state;
1769 eh_region this_region = NULL;
1773 inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
1775 if (flag_exceptions)
1777 this_region = gen_eh_region_allowed (state->cur_region,
1778 gimple_eh_filter_types (inner));
1779 this_state.cur_region = this_region;
1782 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1784 if (!eh_region_may_contain_throw (this_region))
1785 return gimple_try_eval (tp);
1788 this_state.cur_region = state->cur_region;
1789 this_state.ehp_region = this_region;
1791 emit_eh_dispatch (&new_seq, this_region);
1792 emit_resx (&new_seq, this_region);
1794 this_region->u.allowed.label = create_artificial_label (UNKNOWN_LOCATION);
1795 x = gimple_build_label (this_region->u.allowed.label);
1796 gimple_seq_add_stmt (&new_seq, x);
1798 lower_eh_constructs_1 (&this_state, gimple_eh_filter_failure_ptr (inner));
1799 gimple_seq_add_seq (&new_seq, gimple_eh_filter_failure (inner));
1801 gimple_try_set_cleanup (tp, new_seq);
1803 return frob_into_branch_around (tp, this_region, NULL);
1806 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1807 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1808 plus the exception region trees that record all the magic. */
1811 lower_eh_must_not_throw (struct leh_state *state, gimple tp)
1813 struct leh_state this_state = *state;
1815 if (flag_exceptions)
1817 gimple inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
1818 eh_region this_region;
1820 this_region = gen_eh_region_must_not_throw (state->cur_region);
1821 this_region->u.must_not_throw.failure_decl
1822 = gimple_eh_must_not_throw_fndecl (inner);
1823 this_region->u.must_not_throw.failure_loc = gimple_location (tp);
1825 /* In order to get mangling applied to this decl, we must mark it
1826 used now. Otherwise, pass_ipa_free_lang_data won't think it
1828 TREE_USED (this_region->u.must_not_throw.failure_decl) = 1;
1830 this_state.cur_region = this_region;
1833 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1835 return gimple_try_eval (tp);
1838 /* Implement a cleanup expression. This is similar to try-finally,
1839 except that we only execute the cleanup block for exception edges. */
1842 lower_cleanup (struct leh_state *state, gimple tp)
1844 struct leh_state this_state = *state;
1845 eh_region this_region = NULL;
1846 struct leh_tf_state fake_tf;
1848 bool cleanup_dead = cleanup_is_dead_in (state->cur_region);
1850 if (flag_exceptions && !cleanup_dead)
1852 this_region = gen_eh_region_cleanup (state->cur_region);
1853 this_state.cur_region = this_region;
1856 lower_eh_constructs_1 (&this_state, gimple_try_eval_ptr (tp));
1858 if (cleanup_dead || !eh_region_may_contain_throw (this_region))
1859 return gimple_try_eval (tp);
1861 /* Build enough of a try-finally state so that we can reuse
1862 honor_protect_cleanup_actions. */
1863 memset (&fake_tf, 0, sizeof (fake_tf));
1864 fake_tf.top_p = fake_tf.try_finally_expr = tp;
1865 fake_tf.outer = state;
1866 fake_tf.region = this_region;
1867 fake_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
1868 fake_tf.may_throw = true;
1870 honor_protect_cleanup_actions (state, NULL, &fake_tf);
1872 if (fake_tf.may_throw)
1874 /* In this case honor_protect_cleanup_actions had nothing to do,
1875 and we should process this normally. */
1876 lower_eh_constructs_1 (state, gimple_try_cleanup_ptr (tp));
1877 result = frob_into_branch_around (tp, this_region,
1878 fake_tf.fallthru_label);
1882 /* In this case honor_protect_cleanup_actions did nearly all of
1883 the work. All we have left is to append the fallthru_label. */
1885 result = gimple_try_eval (tp);
1886 if (fake_tf.fallthru_label)
1888 gimple x = gimple_build_label (fake_tf.fallthru_label);
1889 gimple_seq_add_stmt (&result, x);
1895 /* Main loop for lowering eh constructs. Also moves gsi to the next
1899 lower_eh_constructs_2 (struct leh_state *state, gimple_stmt_iterator *gsi)
1903 gimple stmt = gsi_stmt (*gsi);
1905 switch (gimple_code (stmt))
1909 tree fndecl = gimple_call_fndecl (stmt);
1912 if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
1913 switch (DECL_FUNCTION_CODE (fndecl))
1915 case BUILT_IN_EH_POINTER:
1916 /* The front end may have generated a call to
1917 __builtin_eh_pointer (0) within a catch region. Replace
1918 this zero argument with the current catch region number. */
1919 if (state->ehp_region)
1921 tree nr = build_int_cst (integer_type_node,
1922 state->ehp_region->index);
1923 gimple_call_set_arg (stmt, 0, nr);
1927 /* The user has dome something silly. Remove it. */
1928 rhs = null_pointer_node;
1933 case BUILT_IN_EH_FILTER:
1934 /* ??? This should never appear, but since it's a builtin it
1935 is accessible to abuse by users. Just remove it and
1936 replace the use with the arbitrary value zero. */
1937 rhs = build_int_cst (TREE_TYPE (TREE_TYPE (fndecl)), 0);
1939 lhs = gimple_call_lhs (stmt);
1940 x = gimple_build_assign (lhs, rhs);
1941 gsi_insert_before (gsi, x, GSI_SAME_STMT);
1944 case BUILT_IN_EH_COPY_VALUES:
1945 /* Likewise this should not appear. Remove it. */
1946 gsi_remove (gsi, true);
1956 /* If the stmt can throw use a new temporary for the assignment
1957 to a LHS. This makes sure the old value of the LHS is
1958 available on the EH edge. Only do so for statements that
1959 potentially fall through (no noreturn calls e.g.), otherwise
1960 this new assignment might create fake fallthru regions. */
1961 if (stmt_could_throw_p (stmt)
1962 && gimple_has_lhs (stmt)
1963 && gimple_stmt_may_fallthru (stmt)
1964 && !tree_could_throw_p (gimple_get_lhs (stmt))
1965 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt))))
1967 tree lhs = gimple_get_lhs (stmt);
1968 tree tmp = create_tmp_var (TREE_TYPE (lhs), NULL);
1969 gimple s = gimple_build_assign (lhs, tmp);
1970 gimple_set_location (s, gimple_location (stmt));
1971 gimple_set_block (s, gimple_block (stmt));
1972 gimple_set_lhs (stmt, tmp);
1973 if (TREE_CODE (TREE_TYPE (tmp)) == COMPLEX_TYPE
1974 || TREE_CODE (TREE_TYPE (tmp)) == VECTOR_TYPE)
1975 DECL_GIMPLE_REG_P (tmp) = 1;
1976 gsi_insert_after (gsi, s, GSI_SAME_STMT);
1978 /* Look for things that can throw exceptions, and record them. */
1979 if (state->cur_region && stmt_could_throw_p (stmt))
1981 record_stmt_eh_region (state->cur_region, stmt);
1982 note_eh_region_may_contain_throw (state->cur_region);
1989 maybe_record_in_goto_queue (state, stmt);
1993 verify_norecord_switch_expr (state, stmt);
1997 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
1998 replace = lower_try_finally (state, stmt);
2001 x = gimple_seq_first_stmt (gimple_try_cleanup (stmt));
2004 replace = gimple_try_eval (stmt);
2005 lower_eh_constructs_1 (state, &replace);
2008 switch (gimple_code (x))
2011 replace = lower_catch (state, stmt);
2013 case GIMPLE_EH_FILTER:
2014 replace = lower_eh_filter (state, stmt);
2016 case GIMPLE_EH_MUST_NOT_THROW:
2017 replace = lower_eh_must_not_throw (state, stmt);
2019 case GIMPLE_EH_ELSE:
2020 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2023 replace = lower_cleanup (state, stmt);
2028 /* Remove the old stmt and insert the transformed sequence
2030 gsi_insert_seq_before (gsi, replace, GSI_SAME_STMT);
2031 gsi_remove (gsi, true);
2033 /* Return since we don't want gsi_next () */
2036 case GIMPLE_EH_ELSE:
2037 /* We should be eliminating this in lower_try_finally et al. */
2041 /* A type, a decl, or some kind of statement that we're not
2042 interested in. Don't walk them. */
2049 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2052 lower_eh_constructs_1 (struct leh_state *state, gimple_seq *pseq)
2054 gimple_stmt_iterator gsi;
2055 for (gsi = gsi_start (*pseq); !gsi_end_p (gsi);)
2056 lower_eh_constructs_2 (state, &gsi);
2060 lower_eh_constructs (void)
2062 struct leh_state null_state;
2065 bodyp = gimple_body (current_function_decl);
2069 finally_tree = htab_create (31, struct_ptr_hash, struct_ptr_eq, free);
2070 eh_region_may_contain_throw_map = BITMAP_ALLOC (NULL);
2071 memset (&null_state, 0, sizeof (null_state));
2073 collect_finally_tree_1 (bodyp, NULL);
2074 lower_eh_constructs_1 (&null_state, &bodyp);
2075 gimple_set_body (current_function_decl, bodyp);
2077 /* We assume there's a return statement, or something, at the end of
2078 the function, and thus ploping the EH sequence afterward won't
2080 gcc_assert (!gimple_seq_may_fallthru (bodyp));
2081 gimple_seq_add_seq (&bodyp, eh_seq);
2083 /* We assume that since BODYP already existed, adding EH_SEQ to it
2084 didn't change its value, and we don't have to re-set the function. */
2085 gcc_assert (bodyp == gimple_body (current_function_decl));
2087 htab_delete (finally_tree);
2088 BITMAP_FREE (eh_region_may_contain_throw_map);
2091 /* If this function needs a language specific EH personality routine
2092 and the frontend didn't already set one do so now. */
2093 if (function_needs_eh_personality (cfun) == eh_personality_lang
2094 && !DECL_FUNCTION_PERSONALITY (current_function_decl))
2095 DECL_FUNCTION_PERSONALITY (current_function_decl)
2096 = lang_hooks.eh_personality ();
2101 struct gimple_opt_pass pass_lower_eh =
2107 lower_eh_constructs, /* execute */
2110 0, /* static_pass_number */
2111 TV_TREE_EH, /* tv_id */
2112 PROP_gimple_lcf, /* properties_required */
2113 PROP_gimple_leh, /* properties_provided */
2114 0, /* properties_destroyed */
2115 0, /* todo_flags_start */
2116 0 /* todo_flags_finish */
2120 /* Create the multiple edges from an EH_DISPATCH statement to all of
2121 the possible handlers for its EH region. Return true if there's
2122 no fallthru edge; false if there is. */
2125 make_eh_dispatch_edges (gimple stmt)
2129 basic_block src, dst;
2131 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
2132 src = gimple_bb (stmt);
2137 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
2139 dst = label_to_block (c->label);
2140 make_edge (src, dst, 0);
2142 /* A catch-all handler doesn't have a fallthru. */
2143 if (c->type_list == NULL)
2148 case ERT_ALLOWED_EXCEPTIONS:
2149 dst = label_to_block (r->u.allowed.label);
2150 make_edge (src, dst, 0);
2160 /* Create the single EH edge from STMT to its nearest landing pad,
2161 if there is such a landing pad within the current function. */
2164 make_eh_edges (gimple stmt)
2166 basic_block src, dst;
2170 lp_nr = lookup_stmt_eh_lp (stmt);
2174 lp = get_eh_landing_pad_from_number (lp_nr);
2175 gcc_assert (lp != NULL);
2177 src = gimple_bb (stmt);
2178 dst = label_to_block (lp->post_landing_pad);
2179 make_edge (src, dst, EDGE_EH);
2182 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2183 do not actually perform the final edge redirection.
2185 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2186 we intend to change the destination EH region as well; this means
2187 EH_LANDING_PAD_NR must already be set on the destination block label.
2188 If false, we're being called from generic cfg manipulation code and we
2189 should preserve our place within the region tree. */
2192 redirect_eh_edge_1 (edge edge_in, basic_block new_bb, bool change_region)
2194 eh_landing_pad old_lp, new_lp;
2197 int old_lp_nr, new_lp_nr;
2198 tree old_label, new_label;
2202 old_bb = edge_in->dest;
2203 old_label = gimple_block_label (old_bb);
2204 old_lp_nr = EH_LANDING_PAD_NR (old_label);
2205 gcc_assert (old_lp_nr > 0);
2206 old_lp = get_eh_landing_pad_from_number (old_lp_nr);
2208 throw_stmt = last_stmt (edge_in->src);
2209 gcc_assert (lookup_stmt_eh_lp (throw_stmt) == old_lp_nr);
2211 new_label = gimple_block_label (new_bb);
2213 /* Look for an existing region that might be using NEW_BB already. */
2214 new_lp_nr = EH_LANDING_PAD_NR (new_label);
2217 new_lp = get_eh_landing_pad_from_number (new_lp_nr);
2218 gcc_assert (new_lp);
2220 /* Unless CHANGE_REGION is true, the new and old landing pad
2221 had better be associated with the same EH region. */
2222 gcc_assert (change_region || new_lp->region == old_lp->region);
2227 gcc_assert (!change_region);
2230 /* Notice when we redirect the last EH edge away from OLD_BB. */
2231 FOR_EACH_EDGE (e, ei, old_bb->preds)
2232 if (e != edge_in && (e->flags & EDGE_EH))
2237 /* NEW_LP already exists. If there are still edges into OLD_LP,
2238 there's nothing to do with the EH tree. If there are no more
2239 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2240 If CHANGE_REGION is true, then our caller is expecting to remove
2242 if (e == NULL && !change_region)
2243 remove_eh_landing_pad (old_lp);
2247 /* No correct landing pad exists. If there are no more edges
2248 into OLD_LP, then we can simply re-use the existing landing pad.
2249 Otherwise, we have to create a new landing pad. */
2252 EH_LANDING_PAD_NR (old_lp->post_landing_pad) = 0;
2256 new_lp = gen_eh_landing_pad (old_lp->region);
2257 new_lp->post_landing_pad = new_label;
2258 EH_LANDING_PAD_NR (new_label) = new_lp->index;
2261 /* Maybe move the throwing statement to the new region. */
2262 if (old_lp != new_lp)
2264 remove_stmt_from_eh_lp (throw_stmt);
2265 add_stmt_to_eh_lp (throw_stmt, new_lp->index);
2269 /* Redirect EH edge E to NEW_BB. */
2272 redirect_eh_edge (edge edge_in, basic_block new_bb)
2274 redirect_eh_edge_1 (edge_in, new_bb, false);
2275 return ssa_redirect_edge (edge_in, new_bb);
2278 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2279 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2280 The actual edge update will happen in the caller. */
2283 redirect_eh_dispatch_edge (gimple stmt, edge e, basic_block new_bb)
2285 tree new_lab = gimple_block_label (new_bb);
2286 bool any_changed = false;
2291 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
2295 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
2297 old_bb = label_to_block (c->label);
2298 if (old_bb == e->dest)
2306 case ERT_ALLOWED_EXCEPTIONS:
2307 old_bb = label_to_block (r->u.allowed.label);
2308 gcc_assert (old_bb == e->dest);
2309 r->u.allowed.label = new_lab;
2317 gcc_assert (any_changed);
2320 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2323 operation_could_trap_helper_p (enum tree_code op,
2334 case TRUNC_DIV_EXPR:
2336 case FLOOR_DIV_EXPR:
2337 case ROUND_DIV_EXPR:
2338 case EXACT_DIV_EXPR:
2340 case FLOOR_MOD_EXPR:
2341 case ROUND_MOD_EXPR:
2342 case TRUNC_MOD_EXPR:
2344 if (honor_snans || honor_trapv)
2347 return flag_trapping_math;
2348 if (!TREE_CONSTANT (divisor) || integer_zerop (divisor))
2357 /* Some floating point comparisons may trap. */
2362 case UNORDERED_EXPR:
2372 case FIX_TRUNC_EXPR:
2373 /* Conversion of floating point might trap. */
2379 /* These operations don't trap with floating point. */
2387 /* Any floating arithmetic may trap. */
2388 if (fp_operation && flag_trapping_math)
2396 /* Constructing an object cannot trap. */
2400 /* Any floating arithmetic may trap. */
2401 if (fp_operation && flag_trapping_math)
2409 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2410 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2411 type operands that may trap. If OP is a division operator, DIVISOR contains
2412 the value of the divisor. */
2415 operation_could_trap_p (enum tree_code op, bool fp_operation, bool honor_trapv,
2418 bool honor_nans = (fp_operation && flag_trapping_math
2419 && !flag_finite_math_only);
2420 bool honor_snans = fp_operation && flag_signaling_nans != 0;
2423 if (TREE_CODE_CLASS (op) != tcc_comparison
2424 && TREE_CODE_CLASS (op) != tcc_unary
2425 && TREE_CODE_CLASS (op) != tcc_binary)
2428 return operation_could_trap_helper_p (op, fp_operation, honor_trapv,
2429 honor_nans, honor_snans, divisor,
2433 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2434 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2435 This routine expects only GIMPLE lhs or rhs input. */
2438 tree_could_trap_p (tree expr)
2440 enum tree_code code;
2441 bool fp_operation = false;
2442 bool honor_trapv = false;
2443 tree t, base, div = NULL_TREE;
2448 code = TREE_CODE (expr);
2449 t = TREE_TYPE (expr);
2453 if (COMPARISON_CLASS_P (expr))
2454 fp_operation = FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0)));
2456 fp_operation = FLOAT_TYPE_P (t);
2457 honor_trapv = INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t);
2460 if (TREE_CODE_CLASS (code) == tcc_binary)
2461 div = TREE_OPERAND (expr, 1);
2462 if (operation_could_trap_p (code, fp_operation, honor_trapv, div))
2468 case TARGET_MEM_REF:
2469 if (TREE_CODE (TMR_BASE (expr)) == ADDR_EXPR
2470 && !TMR_INDEX (expr) && !TMR_INDEX2 (expr))
2472 return !TREE_THIS_NOTRAP (expr);
2478 case VIEW_CONVERT_EXPR:
2479 case WITH_SIZE_EXPR:
2480 expr = TREE_OPERAND (expr, 0);
2481 code = TREE_CODE (expr);
2484 case ARRAY_RANGE_REF:
2485 base = TREE_OPERAND (expr, 0);
2486 if (tree_could_trap_p (base))
2488 if (TREE_THIS_NOTRAP (expr))
2490 return !range_in_array_bounds_p (expr);
2493 base = TREE_OPERAND (expr, 0);
2494 if (tree_could_trap_p (base))
2496 if (TREE_THIS_NOTRAP (expr))
2498 return !in_array_bounds_p (expr);
2501 if (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR)
2505 return !TREE_THIS_NOTRAP (expr);
2508 return TREE_THIS_VOLATILE (expr);
2511 t = get_callee_fndecl (expr);
2512 /* Assume that calls to weak functions may trap. */
2513 if (!t || !DECL_P (t))
2516 return tree_could_trap_p (t);
2520 /* Assume that accesses to weak functions may trap, unless we know
2521 they are certainly defined in current TU or in some other
2523 if (DECL_WEAK (expr))
2525 struct cgraph_node *node;
2526 if (!DECL_EXTERNAL (expr))
2528 node = cgraph_function_node (cgraph_get_node (expr), NULL);
2529 if (node && node->symbol.in_other_partition)
2536 /* Assume that accesses to weak vars may trap, unless we know
2537 they are certainly defined in current TU or in some other
2539 if (DECL_WEAK (expr))
2541 struct varpool_node *node;
2542 if (!DECL_EXTERNAL (expr))
2544 node = varpool_variable_node (varpool_get_node (expr), NULL);
2545 if (node && node->symbol.in_other_partition)
2557 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2558 an assignment or a conditional) may throw. */
2561 stmt_could_throw_1_p (gimple stmt)
2563 enum tree_code code = gimple_expr_code (stmt);
2564 bool honor_nans = false;
2565 bool honor_snans = false;
2566 bool fp_operation = false;
2567 bool honor_trapv = false;
2572 if (TREE_CODE_CLASS (code) == tcc_comparison
2573 || TREE_CODE_CLASS (code) == tcc_unary
2574 || TREE_CODE_CLASS (code) == tcc_binary)
2576 if (is_gimple_assign (stmt)
2577 && TREE_CODE_CLASS (code) == tcc_comparison)
2578 t = TREE_TYPE (gimple_assign_rhs1 (stmt));
2579 else if (gimple_code (stmt) == GIMPLE_COND)
2580 t = TREE_TYPE (gimple_cond_lhs (stmt));
2582 t = gimple_expr_type (stmt);
2583 fp_operation = FLOAT_TYPE_P (t);
2586 honor_nans = flag_trapping_math && !flag_finite_math_only;
2587 honor_snans = flag_signaling_nans != 0;
2589 else if (INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t))
2593 /* Check if the main expression may trap. */
2594 t = is_gimple_assign (stmt) ? gimple_assign_rhs2 (stmt) : NULL;
2595 ret = operation_could_trap_helper_p (code, fp_operation, honor_trapv,
2596 honor_nans, honor_snans, t,
2601 /* If the expression does not trap, see if any of the individual operands may
2603 for (i = 0; i < gimple_num_ops (stmt); i++)
2604 if (tree_could_trap_p (gimple_op (stmt, i)))
2611 /* Return true if statement STMT could throw an exception. */
2614 stmt_could_throw_p (gimple stmt)
2616 if (!flag_exceptions)
2619 /* The only statements that can throw an exception are assignments,
2620 conditionals, calls, resx, and asms. */
2621 switch (gimple_code (stmt))
2627 return !gimple_call_nothrow_p (stmt);
2631 if (!cfun->can_throw_non_call_exceptions)
2633 return stmt_could_throw_1_p (stmt);
2636 if (!cfun->can_throw_non_call_exceptions)
2638 return gimple_asm_volatile_p (stmt);
2646 /* Return true if expression T could throw an exception. */
2649 tree_could_throw_p (tree t)
2651 if (!flag_exceptions)
2653 if (TREE_CODE (t) == MODIFY_EXPR)
2655 if (cfun->can_throw_non_call_exceptions
2656 && tree_could_trap_p (TREE_OPERAND (t, 0)))
2658 t = TREE_OPERAND (t, 1);
2661 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2662 t = TREE_OPERAND (t, 0);
2663 if (TREE_CODE (t) == CALL_EXPR)
2664 return (call_expr_flags (t) & ECF_NOTHROW) == 0;
2665 if (cfun->can_throw_non_call_exceptions)
2666 return tree_could_trap_p (t);
2670 /* Return true if STMT can throw an exception that is not caught within
2671 the current function (CFUN). */
2674 stmt_can_throw_external (gimple stmt)
2678 if (!stmt_could_throw_p (stmt))
2681 lp_nr = lookup_stmt_eh_lp (stmt);
2685 /* Return true if STMT can throw an exception that is caught within
2686 the current function (CFUN). */
2689 stmt_can_throw_internal (gimple stmt)
2693 if (!stmt_could_throw_p (stmt))
2696 lp_nr = lookup_stmt_eh_lp (stmt);
2700 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2701 remove any entry it might have from the EH table. Return true if
2702 any change was made. */
2705 maybe_clean_eh_stmt_fn (struct function *ifun, gimple stmt)
2707 if (stmt_could_throw_p (stmt))
2709 return remove_stmt_from_eh_lp_fn (ifun, stmt);
2712 /* Likewise, but always use the current function. */
2715 maybe_clean_eh_stmt (gimple stmt)
2717 return maybe_clean_eh_stmt_fn (cfun, stmt);
2720 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2721 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2722 in the table if it should be in there. Return TRUE if a replacement was
2723 done that my require an EH edge purge. */
2726 maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt)
2728 int lp_nr = lookup_stmt_eh_lp (old_stmt);
2732 bool new_stmt_could_throw = stmt_could_throw_p (new_stmt);
2734 if (new_stmt == old_stmt && new_stmt_could_throw)
2737 remove_stmt_from_eh_lp (old_stmt);
2738 if (new_stmt_could_throw)
2740 add_stmt_to_eh_lp (new_stmt, lp_nr);
2750 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
2751 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2752 operand is the return value of duplicate_eh_regions. */
2755 maybe_duplicate_eh_stmt_fn (struct function *new_fun, gimple new_stmt,
2756 struct function *old_fun, gimple old_stmt,
2757 struct pointer_map_t *map, int default_lp_nr)
2759 int old_lp_nr, new_lp_nr;
2762 if (!stmt_could_throw_p (new_stmt))
2765 old_lp_nr = lookup_stmt_eh_lp_fn (old_fun, old_stmt);
2768 if (default_lp_nr == 0)
2770 new_lp_nr = default_lp_nr;
2772 else if (old_lp_nr > 0)
2774 eh_landing_pad old_lp, new_lp;
2776 old_lp = VEC_index (eh_landing_pad, old_fun->eh->lp_array, old_lp_nr);
2777 slot = pointer_map_contains (map, old_lp);
2778 new_lp = (eh_landing_pad) *slot;
2779 new_lp_nr = new_lp->index;
2783 eh_region old_r, new_r;
2785 old_r = VEC_index (eh_region, old_fun->eh->region_array, -old_lp_nr);
2786 slot = pointer_map_contains (map, old_r);
2787 new_r = (eh_region) *slot;
2788 new_lp_nr = -new_r->index;
2791 add_stmt_to_eh_lp_fn (new_fun, new_stmt, new_lp_nr);
2795 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2796 and thus no remapping is required. */
2799 maybe_duplicate_eh_stmt (gimple new_stmt, gimple old_stmt)
2803 if (!stmt_could_throw_p (new_stmt))
2806 lp_nr = lookup_stmt_eh_lp (old_stmt);
2810 add_stmt_to_eh_lp (new_stmt, lp_nr);
2814 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2815 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2816 this only handles handlers consisting of a single call, as that's the
2817 important case for C++: a destructor call for a particular object showing
2818 up in multiple handlers. */
2821 same_handler_p (gimple_seq oneh, gimple_seq twoh)
2823 gimple_stmt_iterator gsi;
2827 gsi = gsi_start (oneh);
2828 if (!gsi_one_before_end_p (gsi))
2830 ones = gsi_stmt (gsi);
2832 gsi = gsi_start (twoh);
2833 if (!gsi_one_before_end_p (gsi))
2835 twos = gsi_stmt (gsi);
2837 if (!is_gimple_call (ones)
2838 || !is_gimple_call (twos)
2839 || gimple_call_lhs (ones)
2840 || gimple_call_lhs (twos)
2841 || gimple_call_chain (ones)
2842 || gimple_call_chain (twos)
2843 || !gimple_call_same_target_p (ones, twos)
2844 || gimple_call_num_args (ones) != gimple_call_num_args (twos))
2847 for (ai = 0; ai < gimple_call_num_args (ones); ++ai)
2848 if (!operand_equal_p (gimple_call_arg (ones, ai),
2849 gimple_call_arg (twos, ai), 0))
2856 try { A() } finally { try { ~B() } catch { ~A() } }
2857 try { ... } finally { ~A() }
2859 try { A() } catch { ~B() }
2860 try { ~B() ... } finally { ~A() }
2862 This occurs frequently in C++, where A is a local variable and B is a
2863 temporary used in the initializer for A. */
2866 optimize_double_finally (gimple one, gimple two)
2869 gimple_stmt_iterator gsi;
2872 cleanup = gimple_try_cleanup (one);
2873 gsi = gsi_start (cleanup);
2874 if (!gsi_one_before_end_p (gsi))
2877 oneh = gsi_stmt (gsi);
2878 if (gimple_code (oneh) != GIMPLE_TRY
2879 || gimple_try_kind (oneh) != GIMPLE_TRY_CATCH)
2882 if (same_handler_p (gimple_try_cleanup (oneh), gimple_try_cleanup (two)))
2884 gimple_seq seq = gimple_try_eval (oneh);
2886 gimple_try_set_cleanup (one, seq);
2887 gimple_try_set_kind (one, GIMPLE_TRY_CATCH);
2888 seq = copy_gimple_seq_and_replace_locals (seq);
2889 gimple_seq_add_seq (&seq, gimple_try_eval (two));
2890 gimple_try_set_eval (two, seq);
2894 /* Perform EH refactoring optimizations that are simpler to do when code
2895 flow has been lowered but EH structures haven't. */
2898 refactor_eh_r (gimple_seq seq)
2900 gimple_stmt_iterator gsi;
2905 gsi = gsi_start (seq);
2909 if (gsi_end_p (gsi))
2912 two = gsi_stmt (gsi);
2915 && gimple_code (one) == GIMPLE_TRY
2916 && gimple_code (two) == GIMPLE_TRY
2917 && gimple_try_kind (one) == GIMPLE_TRY_FINALLY
2918 && gimple_try_kind (two) == GIMPLE_TRY_FINALLY)
2919 optimize_double_finally (one, two);
2921 switch (gimple_code (one))
2924 refactor_eh_r (gimple_try_eval (one));
2925 refactor_eh_r (gimple_try_cleanup (one));
2928 refactor_eh_r (gimple_catch_handler (one));
2930 case GIMPLE_EH_FILTER:
2931 refactor_eh_r (gimple_eh_filter_failure (one));
2933 case GIMPLE_EH_ELSE:
2934 refactor_eh_r (gimple_eh_else_n_body (one));
2935 refactor_eh_r (gimple_eh_else_e_body (one));
2950 refactor_eh_r (gimple_body (current_function_decl));
2955 gate_refactor_eh (void)
2957 return flag_exceptions != 0;
2960 struct gimple_opt_pass pass_refactor_eh =
2965 gate_refactor_eh, /* gate */
2966 refactor_eh, /* execute */
2969 0, /* static_pass_number */
2970 TV_TREE_EH, /* tv_id */
2971 PROP_gimple_lcf, /* properties_required */
2972 0, /* properties_provided */
2973 0, /* properties_destroyed */
2974 0, /* todo_flags_start */
2975 0 /* todo_flags_finish */
2979 /* At the end of gimple optimization, we can lower RESX. */
2982 lower_resx (basic_block bb, gimple stmt, struct pointer_map_t *mnt_map)
2985 eh_region src_r, dst_r;
2986 gimple_stmt_iterator gsi;
2991 lp_nr = lookup_stmt_eh_lp (stmt);
2993 dst_r = get_eh_region_from_lp_number (lp_nr);
2997 src_r = get_eh_region_from_number (gimple_resx_region (stmt));
2998 gsi = gsi_last_bb (bb);
3002 /* We can wind up with no source region when pass_cleanup_eh shows
3003 that there are no entries into an eh region and deletes it, but
3004 then the block that contains the resx isn't removed. This can
3005 happen without optimization when the switch statement created by
3006 lower_try_finally_switch isn't simplified to remove the eh case.
3008 Resolve this by expanding the resx node to an abort. */
3010 fn = builtin_decl_implicit (BUILT_IN_TRAP);
3011 x = gimple_build_call (fn, 0);
3012 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3014 while (EDGE_COUNT (bb->succs) > 0)
3015 remove_edge (EDGE_SUCC (bb, 0));
3019 /* When we have a destination region, we resolve this by copying
3020 the excptr and filter values into place, and changing the edge
3021 to immediately after the landing pad. */
3030 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3031 the failure decl into a new block, if needed. */
3032 gcc_assert (dst_r->type == ERT_MUST_NOT_THROW);
3034 slot = pointer_map_contains (mnt_map, dst_r);
3037 gimple_stmt_iterator gsi2;
3039 new_bb = create_empty_bb (bb);
3041 add_bb_to_loop (new_bb, bb->loop_father);
3042 lab = gimple_block_label (new_bb);
3043 gsi2 = gsi_start_bb (new_bb);
3045 fn = dst_r->u.must_not_throw.failure_decl;
3046 x = gimple_build_call (fn, 0);
3047 gimple_set_location (x, dst_r->u.must_not_throw.failure_loc);
3048 gsi_insert_after (&gsi2, x, GSI_CONTINUE_LINKING);
3050 slot = pointer_map_insert (mnt_map, dst_r);
3056 new_bb = label_to_block (lab);
3059 gcc_assert (EDGE_COUNT (bb->succs) == 0);
3060 e = make_edge (bb, new_bb, EDGE_FALLTHRU);
3061 e->count = bb->count;
3062 e->probability = REG_BR_PROB_BASE;
3067 tree dst_nr = build_int_cst (integer_type_node, dst_r->index);
3069 fn = builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES);
3070 src_nr = build_int_cst (integer_type_node, src_r->index);
3071 x = gimple_build_call (fn, 2, dst_nr, src_nr);
3072 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3074 /* Update the flags for the outgoing edge. */
3075 e = single_succ_edge (bb);
3076 gcc_assert (e->flags & EDGE_EH);
3077 e->flags = (e->flags & ~EDGE_EH) | EDGE_FALLTHRU;
3079 /* If there are no more EH users of the landing pad, delete it. */
3080 FOR_EACH_EDGE (e, ei, e->dest->preds)
3081 if (e->flags & EDGE_EH)
3085 eh_landing_pad lp = get_eh_landing_pad_from_number (lp_nr);
3086 remove_eh_landing_pad (lp);
3096 /* When we don't have a destination region, this exception escapes
3097 up the call chain. We resolve this by generating a call to the
3098 _Unwind_Resume library function. */
3100 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3101 with no arguments for C++ and Java. Check for that. */
3102 if (src_r->use_cxa_end_cleanup)
3104 fn = builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP);
3105 x = gimple_build_call (fn, 0);
3106 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3110 fn = builtin_decl_implicit (BUILT_IN_EH_POINTER);
3111 src_nr = build_int_cst (integer_type_node, src_r->index);
3112 x = gimple_build_call (fn, 1, src_nr);
3113 var = create_tmp_var (ptr_type_node, NULL);
3114 var = make_ssa_name (var, x);
3115 gimple_call_set_lhs (x, var);
3116 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3118 fn = builtin_decl_implicit (BUILT_IN_UNWIND_RESUME);
3119 x = gimple_build_call (fn, 1, var);
3120 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3123 gcc_assert (EDGE_COUNT (bb->succs) == 0);
3126 gsi_remove (&gsi, true);
3132 execute_lower_resx (void)
3135 struct pointer_map_t *mnt_map;
3136 bool dominance_invalidated = false;
3137 bool any_rewritten = false;
3139 mnt_map = pointer_map_create ();
3143 gimple last = last_stmt (bb);
3144 if (last && is_gimple_resx (last))
3146 dominance_invalidated |= lower_resx (bb, last, mnt_map);
3147 any_rewritten = true;
3151 pointer_map_destroy (mnt_map);
3153 if (dominance_invalidated)
3155 free_dominance_info (CDI_DOMINATORS);
3156 free_dominance_info (CDI_POST_DOMINATORS);
3159 return any_rewritten ? TODO_update_ssa_only_virtuals : 0;
3163 gate_lower_resx (void)
3165 return flag_exceptions != 0;
3168 struct gimple_opt_pass pass_lower_resx =
3173 gate_lower_resx, /* gate */
3174 execute_lower_resx, /* execute */
3177 0, /* static_pass_number */
3178 TV_TREE_EH, /* tv_id */
3179 PROP_gimple_lcf, /* properties_required */
3180 0, /* properties_provided */
3181 0, /* properties_destroyed */
3182 0, /* todo_flags_start */
3183 TODO_verify_flow /* todo_flags_finish */
3187 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3191 optimize_clobbers (basic_block bb)
3193 gimple_stmt_iterator gsi = gsi_last_bb (bb);
3194 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3196 gimple stmt = gsi_stmt (gsi);
3197 if (is_gimple_debug (stmt))
3199 if (!gimple_clobber_p (stmt)
3200 || TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME)
3202 unlink_stmt_vdef (stmt);
3203 gsi_remove (&gsi, true);
3204 release_defs (stmt);
3208 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3209 internal throw to successor BB. */
3212 sink_clobbers (basic_block bb)
3216 gimple_stmt_iterator gsi, dgsi;
3218 bool any_clobbers = false;
3220 /* Only optimize if BB has a single EH successor and
3221 all predecessor edges are EH too. */
3222 if (!single_succ_p (bb)
3223 || (single_succ_edge (bb)->flags & EDGE_EH) == 0)
3226 FOR_EACH_EDGE (e, ei, bb->preds)
3228 if ((e->flags & EDGE_EH) == 0)
3232 /* And BB contains only CLOBBER stmts before the final
3234 gsi = gsi_last_bb (bb);
3235 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3237 gimple stmt = gsi_stmt (gsi);
3238 if (is_gimple_debug (stmt))
3240 if (gimple_code (stmt) == GIMPLE_LABEL)
3242 if (!gimple_clobber_p (stmt)
3243 || TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME)
3245 any_clobbers = true;
3250 succbb = single_succ (bb);
3251 dgsi = gsi_after_labels (succbb);
3252 gsi = gsi_last_bb (bb);
3253 for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
3255 gimple stmt = gsi_stmt (gsi);
3257 if (is_gimple_debug (stmt))
3259 if (gimple_code (stmt) == GIMPLE_LABEL)
3261 unlink_stmt_vdef (stmt);
3262 gsi_remove (&gsi, false);
3263 vdef = gimple_vdef (stmt);
3264 if (vdef && TREE_CODE (vdef) == SSA_NAME)
3266 release_ssa_name (vdef);
3267 vdef = SSA_NAME_VAR (vdef);
3268 mark_sym_for_renaming (vdef);
3269 gimple_set_vdef (stmt, vdef);
3270 gimple_set_vuse (stmt, vdef);
3272 gsi_insert_before (&dgsi, stmt, GSI_SAME_STMT);
3275 return TODO_update_ssa_only_virtuals;
3278 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3279 we have found some duplicate labels and removed some edges. */
3282 lower_eh_dispatch (basic_block src, gimple stmt)
3284 gimple_stmt_iterator gsi;
3289 bool redirected = false;
3291 region_nr = gimple_eh_dispatch_region (stmt);
3292 r = get_eh_region_from_number (region_nr);
3294 gsi = gsi_last_bb (src);
3300 VEC (tree, heap) *labels = NULL;
3301 tree default_label = NULL;
3305 struct pointer_set_t *seen_values = pointer_set_create ();
3307 /* Collect the labels for a switch. Zero the post_landing_pad
3308 field becase we'll no longer have anything keeping these labels
3309 in existence and the optimizer will be free to merge these
3311 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
3313 tree tp_node, flt_node, lab = c->label;
3314 bool have_label = false;
3317 tp_node = c->type_list;
3318 flt_node = c->filter_list;
3320 if (tp_node == NULL)
3322 default_label = lab;
3327 /* Filter out duplicate labels that arise when this handler
3328 is shadowed by an earlier one. When no labels are
3329 attached to the handler anymore, we remove
3330 the corresponding edge and then we delete unreachable
3331 blocks at the end of this pass. */
3332 if (! pointer_set_contains (seen_values, TREE_VALUE (flt_node)))
3334 tree t = build_case_label (TREE_VALUE (flt_node),
3336 VEC_safe_push (tree, heap, labels, t);
3337 pointer_set_insert (seen_values, TREE_VALUE (flt_node));
3341 tp_node = TREE_CHAIN (tp_node);
3342 flt_node = TREE_CHAIN (flt_node);
3347 remove_edge (find_edge (src, label_to_block (lab)));
3352 /* Clean up the edge flags. */
3353 FOR_EACH_EDGE (e, ei, src->succs)
3355 if (e->flags & EDGE_FALLTHRU)
3357 /* If there was no catch-all, use the fallthru edge. */
3358 if (default_label == NULL)
3359 default_label = gimple_block_label (e->dest);
3360 e->flags &= ~EDGE_FALLTHRU;
3363 gcc_assert (default_label != NULL);
3365 /* Don't generate a switch if there's only a default case.
3366 This is common in the form of try { A; } catch (...) { B; }. */
3369 e = single_succ_edge (src);
3370 e->flags |= EDGE_FALLTHRU;
3374 fn = builtin_decl_implicit (BUILT_IN_EH_FILTER);
3375 x = gimple_build_call (fn, 1, build_int_cst (integer_type_node,
3377 filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
3378 filter = make_ssa_name (filter, x);
3379 gimple_call_set_lhs (x, filter);
3380 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3382 /* Turn the default label into a default case. */
3383 default_label = build_case_label (NULL, NULL, default_label);
3384 sort_case_labels (labels);
3386 x = gimple_build_switch_vec (filter, default_label, labels);
3387 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3389 VEC_free (tree, heap, labels);
3391 pointer_set_destroy (seen_values);
3395 case ERT_ALLOWED_EXCEPTIONS:
3397 edge b_e = BRANCH_EDGE (src);
3398 edge f_e = FALLTHRU_EDGE (src);
3400 fn = builtin_decl_implicit (BUILT_IN_EH_FILTER);
3401 x = gimple_build_call (fn, 1, build_int_cst (integer_type_node,
3403 filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
3404 filter = make_ssa_name (filter, x);
3405 gimple_call_set_lhs (x, filter);
3406 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3408 r->u.allowed.label = NULL;
3409 x = gimple_build_cond (EQ_EXPR, filter,
3410 build_int_cst (TREE_TYPE (filter),
3411 r->u.allowed.filter),
3412 NULL_TREE, NULL_TREE);
3413 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3415 b_e->flags = b_e->flags | EDGE_TRUE_VALUE;
3416 f_e->flags = (f_e->flags & ~EDGE_FALLTHRU) | EDGE_FALSE_VALUE;
3424 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3425 gsi_remove (&gsi, true);
3430 execute_lower_eh_dispatch (void)
3434 bool redirected = false;
3436 assign_filter_values ();
3440 gimple last = last_stmt (bb);
3443 if (gimple_code (last) == GIMPLE_EH_DISPATCH)
3445 redirected |= lower_eh_dispatch (bb, last);
3446 flags |= TODO_update_ssa_only_virtuals;
3448 else if (gimple_code (last) == GIMPLE_RESX)
3450 if (stmt_can_throw_external (last))
3451 optimize_clobbers (bb);
3453 flags |= sink_clobbers (bb);
3458 delete_unreachable_blocks ();
3463 gate_lower_eh_dispatch (void)
3465 return cfun->eh->region_tree != NULL;
3468 struct gimple_opt_pass pass_lower_eh_dispatch =
3472 "ehdisp", /* name */
3473 gate_lower_eh_dispatch, /* gate */
3474 execute_lower_eh_dispatch, /* execute */
3477 0, /* static_pass_number */
3478 TV_TREE_EH, /* tv_id */
3479 PROP_gimple_lcf, /* properties_required */
3480 0, /* properties_provided */
3481 0, /* properties_destroyed */
3482 0, /* todo_flags_start */
3483 TODO_verify_flow /* todo_flags_finish */
3487 /* Walk statements, see what regions are really referenced and remove
3488 those that are unused. */
3491 remove_unreachable_handlers (void)
3493 sbitmap r_reachable, lp_reachable;
3499 r_reachable = sbitmap_alloc (VEC_length (eh_region, cfun->eh->region_array));
3501 = sbitmap_alloc (VEC_length (eh_landing_pad, cfun->eh->lp_array));
3502 sbitmap_zero (r_reachable);
3503 sbitmap_zero (lp_reachable);
3507 gimple_stmt_iterator gsi;
3509 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
3511 gimple stmt = gsi_stmt (gsi);
3512 lp_nr = lookup_stmt_eh_lp (stmt);
3514 /* Negative LP numbers are MUST_NOT_THROW regions which
3515 are not considered BB enders. */
3517 SET_BIT (r_reachable, -lp_nr);
3519 /* Positive LP numbers are real landing pads, are are BB enders. */
3522 gcc_assert (gsi_one_before_end_p (gsi));
3523 region = get_eh_region_from_lp_number (lp_nr);
3524 SET_BIT (r_reachable, region->index);
3525 SET_BIT (lp_reachable, lp_nr);
3528 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3529 switch (gimple_code (stmt))
3532 SET_BIT (r_reachable, gimple_resx_region (stmt));
3534 case GIMPLE_EH_DISPATCH:
3535 SET_BIT (r_reachable, gimple_eh_dispatch_region (stmt));
3545 fprintf (dump_file, "Before removal of unreachable regions:\n");
3546 dump_eh_tree (dump_file, cfun);
3547 fprintf (dump_file, "Reachable regions: ");
3548 dump_sbitmap_file (dump_file, r_reachable);
3549 fprintf (dump_file, "Reachable landing pads: ");
3550 dump_sbitmap_file (dump_file, lp_reachable);
3554 VEC_iterate (eh_region, cfun->eh->region_array, r_nr, region); ++r_nr)
3555 if (region && !TEST_BIT (r_reachable, r_nr))
3558 fprintf (dump_file, "Removing unreachable region %d\n", r_nr);
3559 remove_eh_handler (region);
3563 VEC_iterate (eh_landing_pad, cfun->eh->lp_array, lp_nr, lp); ++lp_nr)
3564 if (lp && !TEST_BIT (lp_reachable, lp_nr))
3567 fprintf (dump_file, "Removing unreachable landing pad %d\n", lp_nr);
3568 remove_eh_landing_pad (lp);
3573 fprintf (dump_file, "\n\nAfter removal of unreachable regions:\n");
3574 dump_eh_tree (dump_file, cfun);
3575 fprintf (dump_file, "\n\n");
3578 sbitmap_free (r_reachable);
3579 sbitmap_free (lp_reachable);
3581 #ifdef ENABLE_CHECKING
3582 verify_eh_tree (cfun);
3586 /* Remove unreachable handlers if any landing pads have been removed after
3587 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3590 maybe_remove_unreachable_handlers (void)
3595 if (cfun->eh == NULL)
3598 for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
3599 if (lp && lp->post_landing_pad)
3601 if (label_to_block (lp->post_landing_pad) == NULL)
3603 remove_unreachable_handlers ();
3609 /* Remove regions that do not have landing pads. This assumes
3610 that remove_unreachable_handlers has already been run, and
3611 that we've just manipulated the landing pads since then. */
3614 remove_unreachable_handlers_no_lp (void)
3618 sbitmap r_reachable;
3621 r_reachable = sbitmap_alloc (VEC_length (eh_region, cfun->eh->region_array));
3622 sbitmap_zero (r_reachable);
3626 gimple stmt = last_stmt (bb);
3628 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3629 switch (gimple_code (stmt))
3632 SET_BIT (r_reachable, gimple_resx_region (stmt));
3634 case GIMPLE_EH_DISPATCH:
3635 SET_BIT (r_reachable, gimple_eh_dispatch_region (stmt));
3642 for (i = 1; VEC_iterate (eh_region, cfun->eh->region_array, i, r); ++i)
3643 if (r && r->landing_pads == NULL && r->type != ERT_MUST_NOT_THROW
3644 && !TEST_BIT (r_reachable, i))
3647 fprintf (dump_file, "Removing unreachable region %d\n", i);
3648 remove_eh_handler (r);
3651 sbitmap_free (r_reachable);
3654 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3655 optimisticaly split all sorts of edges, including EH edges. The
3656 optimization passes in between may not have needed them; if not,
3657 we should undo the split.
3659 Recognize this case by having one EH edge incoming to the BB and
3660 one normal edge outgoing; BB should be empty apart from the
3661 post_landing_pad label.
3663 Note that this is slightly different from the empty handler case
3664 handled by cleanup_empty_eh, in that the actual handler may yet
3665 have actual code but the landing pad has been separated from the
3666 handler. As such, cleanup_empty_eh relies on this transformation
3667 having been done first. */
3670 unsplit_eh (eh_landing_pad lp)
3672 basic_block bb = label_to_block (lp->post_landing_pad);
3673 gimple_stmt_iterator gsi;
3676 /* Quickly check the edge counts on BB for singularity. */
3677 if (EDGE_COUNT (bb->preds) != 1 || EDGE_COUNT (bb->succs) != 1)
3679 e_in = EDGE_PRED (bb, 0);
3680 e_out = EDGE_SUCC (bb, 0);
3682 /* Input edge must be EH and output edge must be normal. */
3683 if ((e_in->flags & EDGE_EH) == 0 || (e_out->flags & EDGE_EH) != 0)
3686 /* The block must be empty except for the labels and debug insns. */
3687 gsi = gsi_after_labels (bb);
3688 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
3689 gsi_next_nondebug (&gsi);
3690 if (!gsi_end_p (gsi))
3693 /* The destination block must not already have a landing pad
3694 for a different region. */
3695 for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
3697 gimple stmt = gsi_stmt (gsi);
3701 if (gimple_code (stmt) != GIMPLE_LABEL)
3703 lab = gimple_label_label (stmt);
3704 lp_nr = EH_LANDING_PAD_NR (lab);
3705 if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
3709 /* The new destination block must not already be a destination of
3710 the source block, lest we merge fallthru and eh edges and get
3711 all sorts of confused. */
3712 if (find_edge (e_in->src, e_out->dest))
3715 /* ??? We can get degenerate phis due to cfg cleanups. I would have
3716 thought this should have been cleaned up by a phicprop pass, but
3717 that doesn't appear to handle virtuals. Propagate by hand. */
3718 if (!gimple_seq_empty_p (phi_nodes (bb)))
3720 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
3722 gimple use_stmt, phi = gsi_stmt (gsi);
3723 tree lhs = gimple_phi_result (phi);
3724 tree rhs = gimple_phi_arg_def (phi, 0);
3725 use_operand_p use_p;
3726 imm_use_iterator iter;
3728 FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
3730 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
3731 SET_USE (use_p, rhs);
3734 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
3735 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
3737 remove_phi_node (&gsi, true);
3741 if (dump_file && (dump_flags & TDF_DETAILS))
3742 fprintf (dump_file, "Unsplit EH landing pad %d to block %i.\n",
3743 lp->index, e_out->dest->index);
3745 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
3746 a successor edge, humor it. But do the real CFG change with the
3747 predecessor of E_OUT in order to preserve the ordering of arguments
3748 to the PHI nodes in E_OUT->DEST. */
3749 redirect_eh_edge_1 (e_in, e_out->dest, false);
3750 redirect_edge_pred (e_out, e_in->src);
3751 e_out->flags = e_in->flags;
3752 e_out->probability = e_in->probability;
3753 e_out->count = e_in->count;
3759 /* Examine each landing pad block and see if it matches unsplit_eh. */
3762 unsplit_all_eh (void)
3764 bool changed = false;
3768 for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
3770 changed |= unsplit_eh (lp);
3775 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
3776 to OLD_BB to NEW_BB; return true on success, false on failure.
3778 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
3779 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
3780 Virtual PHIs may be deleted and marked for renaming. */
3783 cleanup_empty_eh_merge_phis (basic_block new_bb, basic_block old_bb,
3784 edge old_bb_out, bool change_region)
3786 gimple_stmt_iterator ngsi, ogsi;
3789 bitmap rename_virts;
3790 bitmap ophi_handled;
3792 /* The destination block must not be a regular successor for any
3793 of the preds of the landing pad. Thus, avoid turning
3803 which CFG verification would choke on. See PR45172 and PR51089. */
3804 FOR_EACH_EDGE (e, ei, old_bb->preds)
3805 if (find_edge (e->src, new_bb))
3808 FOR_EACH_EDGE (e, ei, old_bb->preds)
3809 redirect_edge_var_map_clear (e);
3811 ophi_handled = BITMAP_ALLOC (NULL);
3812 rename_virts = BITMAP_ALLOC (NULL);
3814 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
3815 for the edges we're going to move. */
3816 for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); gsi_next (&ngsi))
3818 gimple ophi, nphi = gsi_stmt (ngsi);
3821 nresult = gimple_phi_result (nphi);
3822 nop = gimple_phi_arg_def (nphi, old_bb_out->dest_idx);
3824 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
3825 the source ssa_name. */
3827 for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
3829 ophi = gsi_stmt (ogsi);
3830 if (gimple_phi_result (ophi) == nop)
3835 /* If we did find the corresponding PHI, copy those inputs. */
3838 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
3839 if (!has_single_use (nop))
3841 imm_use_iterator imm_iter;
3842 use_operand_p use_p;
3844 FOR_EACH_IMM_USE_FAST (use_p, imm_iter, nop)
3846 if (!gimple_debug_bind_p (USE_STMT (use_p))
3847 && (gimple_code (USE_STMT (use_p)) != GIMPLE_PHI
3848 || gimple_bb (USE_STMT (use_p)) != new_bb))
3852 bitmap_set_bit (ophi_handled, SSA_NAME_VERSION (nop));
3853 FOR_EACH_EDGE (e, ei, old_bb->preds)
3858 if ((e->flags & EDGE_EH) == 0)
3860 oop = gimple_phi_arg_def (ophi, e->dest_idx);
3861 oloc = gimple_phi_arg_location (ophi, e->dest_idx);
3862 redirect_edge_var_map_add (e, nresult, oop, oloc);
3865 /* If we didn't find the PHI, but it's a VOP, remember to rename
3866 it later, assuming all other tests succeed. */
3867 else if (!is_gimple_reg (nresult))
3868 bitmap_set_bit (rename_virts, SSA_NAME_VERSION (nresult));
3869 /* If we didn't find the PHI, and it's a real variable, we know
3870 from the fact that OLD_BB is tree_empty_eh_handler_p that the
3871 variable is unchanged from input to the block and we can simply
3872 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
3876 = gimple_phi_arg_location (nphi, old_bb_out->dest_idx);
3877 FOR_EACH_EDGE (e, ei, old_bb->preds)
3878 redirect_edge_var_map_add (e, nresult, nop, nloc);
3882 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
3883 we don't know what values from the other edges into NEW_BB to use. */
3884 for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
3886 gimple ophi = gsi_stmt (ogsi);
3887 tree oresult = gimple_phi_result (ophi);
3888 if (!bitmap_bit_p (ophi_handled, SSA_NAME_VERSION (oresult)))
3892 /* At this point we know that the merge will succeed. Remove the PHI
3893 nodes for the virtuals that we want to rename. */
3894 if (!bitmap_empty_p (rename_virts))
3896 for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); )
3898 gimple nphi = gsi_stmt (ngsi);
3899 tree nresult = gimple_phi_result (nphi);
3900 if (bitmap_bit_p (rename_virts, SSA_NAME_VERSION (nresult)))
3902 mark_virtual_phi_result_for_renaming (nphi);
3903 remove_phi_node (&ngsi, true);
3910 /* Finally, move the edges and update the PHIs. */
3911 for (ei = ei_start (old_bb->preds); (e = ei_safe_edge (ei)); )
3912 if (e->flags & EDGE_EH)
3914 /* ??? CFG manipluation routines do not try to update loop
3915 form on edge redirection. Do so manually here for now. */
3916 /* If we redirect a loop entry or latch edge that will either create
3917 a multiple entry loop or rotate the loop. If the loops merge
3918 we may have created a loop with multiple latches.
3919 All of this isn't easily fixed thus cancel the affected loop
3920 and mark the other loop as possibly having multiple latches. */
3922 && e->dest == e->dest->loop_father->header)
3924 e->dest->loop_father->header = NULL;
3925 e->dest->loop_father->latch = NULL;
3926 new_bb->loop_father->latch = NULL;
3927 loops_state_set (LOOPS_NEED_FIXUP|LOOPS_MAY_HAVE_MULTIPLE_LATCHES);
3929 redirect_eh_edge_1 (e, new_bb, change_region);
3930 redirect_edge_succ (e, new_bb);
3931 flush_pending_stmts (e);
3936 BITMAP_FREE (ophi_handled);
3937 BITMAP_FREE (rename_virts);
3941 FOR_EACH_EDGE (e, ei, old_bb->preds)
3942 redirect_edge_var_map_clear (e);
3943 BITMAP_FREE (ophi_handled);
3944 BITMAP_FREE (rename_virts);
3948 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
3949 old region to NEW_REGION at BB. */
3952 cleanup_empty_eh_move_lp (basic_block bb, edge e_out,
3953 eh_landing_pad lp, eh_region new_region)
3955 gimple_stmt_iterator gsi;
3958 for (pp = &lp->region->landing_pads; *pp != lp; pp = &(*pp)->next_lp)
3962 lp->region = new_region;
3963 lp->next_lp = new_region->landing_pads;
3964 new_region->landing_pads = lp;
3966 /* Delete the RESX that was matched within the empty handler block. */
3967 gsi = gsi_last_bb (bb);
3968 unlink_stmt_vdef (gsi_stmt (gsi));
3969 gsi_remove (&gsi, true);
3971 /* Clean up E_OUT for the fallthru. */
3972 e_out->flags = (e_out->flags & ~EDGE_EH) | EDGE_FALLTHRU;
3973 e_out->probability = REG_BR_PROB_BASE;
3976 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
3977 unsplitting than unsplit_eh was prepared to handle, e.g. when
3978 multiple incoming edges and phis are involved. */
3981 cleanup_empty_eh_unsplit (basic_block bb, edge e_out, eh_landing_pad lp)
3983 gimple_stmt_iterator gsi;
3986 /* We really ought not have totally lost everything following
3987 a landing pad label. Given that BB is empty, there had better
3989 gcc_assert (e_out != NULL);
3991 /* The destination block must not already have a landing pad
3992 for a different region. */
3994 for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
3996 gimple stmt = gsi_stmt (gsi);
3999 if (gimple_code (stmt) != GIMPLE_LABEL)
4001 lab = gimple_label_label (stmt);
4002 lp_nr = EH_LANDING_PAD_NR (lab);
4003 if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
4007 /* Attempt to move the PHIs into the successor block. */
4008 if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, false))
4010 if (dump_file && (dump_flags & TDF_DETAILS))
4012 "Unsplit EH landing pad %d to block %i "
4013 "(via cleanup_empty_eh).\n",
4014 lp->index, e_out->dest->index);
4021 /* Return true if edge E_FIRST is part of an empty infinite loop
4022 or leads to such a loop through a series of single successor
4026 infinite_empty_loop_p (edge e_first)
4028 bool inf_loop = false;
4031 if (e_first->dest == e_first->src)
4034 e_first->src->aux = (void *) 1;
4035 for (e = e_first; single_succ_p (e->dest); e = single_succ_edge (e->dest))
4037 gimple_stmt_iterator gsi;
4043 e->dest->aux = (void *) 1;
4044 gsi = gsi_after_labels (e->dest);
4045 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
4046 gsi_next_nondebug (&gsi);
4047 if (!gsi_end_p (gsi))
4050 e_first->src->aux = NULL;
4051 for (e = e_first; e->dest->aux; e = single_succ_edge (e->dest))
4052 e->dest->aux = NULL;
4057 /* Examine the block associated with LP to determine if it's an empty
4058 handler for its EH region. If so, attempt to redirect EH edges to
4059 an outer region. Return true the CFG was updated in any way. This
4060 is similar to jump forwarding, just across EH edges. */
4063 cleanup_empty_eh (eh_landing_pad lp)
4065 basic_block bb = label_to_block (lp->post_landing_pad);
4066 gimple_stmt_iterator gsi;
4068 eh_region new_region;
4071 bool has_non_eh_pred;
4075 /* There can be zero or one edges out of BB. This is the quickest test. */
4076 switch (EDGE_COUNT (bb->succs))
4082 e_out = EDGE_SUCC (bb, 0);
4088 resx = last_stmt (bb);
4089 if (resx && is_gimple_resx (resx))
4091 if (stmt_can_throw_external (resx))
4092 optimize_clobbers (bb);
4093 else if (sink_clobbers (bb))
4097 gsi = gsi_after_labels (bb);
4099 /* Make sure to skip debug statements. */
4100 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
4101 gsi_next_nondebug (&gsi);
4103 /* If the block is totally empty, look for more unsplitting cases. */
4104 if (gsi_end_p (gsi))
4106 /* For the degenerate case of an infinite loop bail out. */
4107 if (infinite_empty_loop_p (e_out))
4110 return ret | cleanup_empty_eh_unsplit (bb, e_out, lp);
4113 /* The block should consist only of a single RESX statement, modulo a
4114 preceding call to __builtin_stack_restore if there is no outgoing
4115 edge, since the call can be eliminated in this case. */
4116 resx = gsi_stmt (gsi);
4117 if (!e_out && gimple_call_builtin_p (resx, BUILT_IN_STACK_RESTORE))
4120 resx = gsi_stmt (gsi);
4122 if (!is_gimple_resx (resx))
4124 gcc_assert (gsi_one_before_end_p (gsi));
4126 /* Determine if there are non-EH edges, or resx edges into the handler. */
4127 has_non_eh_pred = false;
4128 FOR_EACH_EDGE (e, ei, bb->preds)
4129 if (!(e->flags & EDGE_EH))
4130 has_non_eh_pred = true;
4132 /* Find the handler that's outer of the empty handler by looking at
4133 where the RESX instruction was vectored. */
4134 new_lp_nr = lookup_stmt_eh_lp (resx);
4135 new_region = get_eh_region_from_lp_number (new_lp_nr);
4137 /* If there's no destination region within the current function,
4138 redirection is trivial via removing the throwing statements from
4139 the EH region, removing the EH edges, and allowing the block
4140 to go unreachable. */
4141 if (new_region == NULL)
4143 gcc_assert (e_out == NULL);
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);
4156 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4157 to handle the abort and allow the blocks to go unreachable. */
4158 if (new_region->type == ERT_MUST_NOT_THROW)
4160 for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
4161 if (e->flags & EDGE_EH)
4163 gimple stmt = last_stmt (e->src);
4164 remove_stmt_from_eh_lp (stmt);
4165 add_stmt_to_eh_lp (stmt, new_lp_nr);
4173 /* Try to redirect the EH edges and merge the PHIs into the destination
4174 landing pad block. If the merge succeeds, we'll already have redirected
4175 all the EH edges. The handler itself will go unreachable if there were
4177 if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, true))
4180 /* Finally, if all input edges are EH edges, then we can (potentially)
4181 reduce the number of transfers from the runtime by moving the landing
4182 pad from the original region to the new region. This is a win when
4183 we remove the last CLEANUP region along a particular exception
4184 propagation path. Since nothing changes except for the region with
4185 which the landing pad is associated, the PHI nodes do not need to be
4187 if (!has_non_eh_pred)
4189 cleanup_empty_eh_move_lp (bb, e_out, lp, new_region);
4190 if (dump_file && (dump_flags & TDF_DETAILS))
4191 fprintf (dump_file, "Empty EH handler %i moved to EH region %i.\n",
4192 lp->index, new_region->index);
4194 /* ??? The CFG didn't change, but we may have rendered the
4195 old EH region unreachable. Trigger a cleanup there. */
4202 if (dump_file && (dump_flags & TDF_DETAILS))
4203 fprintf (dump_file, "Empty EH handler %i removed.\n", lp->index);
4204 remove_eh_landing_pad (lp);
4208 /* Do a post-order traversal of the EH region tree. Examine each
4209 post_landing_pad block and see if we can eliminate it as empty. */
4212 cleanup_all_empty_eh (void)
4214 bool changed = false;
4218 for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
4220 changed |= cleanup_empty_eh (lp);
4225 /* Perform cleanups and lowering of exception handling
4226 1) cleanups regions with handlers doing nothing are optimized out
4227 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4228 3) Info about regions that are containing instructions, and regions
4229 reachable via local EH edges is collected
4230 4) Eh tree is pruned for regions no longer neccesary.
4232 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4233 Unify those that have the same failure decl and locus.
4237 execute_cleanup_eh_1 (void)
4239 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4240 looking up unreachable landing pads. */
4241 remove_unreachable_handlers ();
4243 /* Watch out for the region tree vanishing due to all unreachable. */
4244 if (cfun->eh->region_tree && optimize)
4246 bool changed = false;
4248 changed |= unsplit_all_eh ();
4249 changed |= cleanup_all_empty_eh ();
4253 free_dominance_info (CDI_DOMINATORS);
4254 free_dominance_info (CDI_POST_DOMINATORS);
4256 /* We delayed all basic block deletion, as we may have performed
4257 cleanups on EH edges while non-EH edges were still present. */
4258 delete_unreachable_blocks ();
4260 /* We manipulated the landing pads. Remove any region that no
4261 longer has a landing pad. */
4262 remove_unreachable_handlers_no_lp ();
4264 return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals;
4272 execute_cleanup_eh (void)
4274 int ret = execute_cleanup_eh_1 ();
4276 /* If the function no longer needs an EH personality routine
4277 clear it. This exposes cross-language inlining opportunities
4278 and avoids references to a never defined personality routine. */
4279 if (DECL_FUNCTION_PERSONALITY (current_function_decl)
4280 && function_needs_eh_personality (cfun) != eh_personality_lang)
4281 DECL_FUNCTION_PERSONALITY (current_function_decl) = NULL_TREE;
4287 gate_cleanup_eh (void)
4289 return cfun->eh != NULL && cfun->eh->region_tree != NULL;
4292 struct gimple_opt_pass pass_cleanup_eh = {
4295 "ehcleanup", /* name */
4296 gate_cleanup_eh, /* gate */
4297 execute_cleanup_eh, /* execute */
4300 0, /* static_pass_number */
4301 TV_TREE_EH, /* tv_id */
4302 PROP_gimple_lcf, /* properties_required */
4303 0, /* properties_provided */
4304 0, /* properties_destroyed */
4305 0, /* todo_flags_start */
4306 0 /* todo_flags_finish */
4310 /* Verify that BB containing STMT as the last statement, has precisely the
4311 edge that make_eh_edges would create. */
4314 verify_eh_edges (gimple stmt)
4316 basic_block bb = gimple_bb (stmt);
4317 eh_landing_pad lp = NULL;
4322 lp_nr = lookup_stmt_eh_lp (stmt);
4324 lp = get_eh_landing_pad_from_number (lp_nr);
4327 FOR_EACH_EDGE (e, ei, bb->succs)
4329 if (e->flags & EDGE_EH)
4333 error ("BB %i has multiple EH edges", bb->index);
4345 error ("BB %i can not throw but has an EH edge", bb->index);
4351 if (!stmt_could_throw_p (stmt))
4353 error ("BB %i last statement has incorrectly set lp", bb->index);
4357 if (eh_edge == NULL)
4359 error ("BB %i is missing an EH edge", bb->index);
4363 if (eh_edge->dest != label_to_block (lp->post_landing_pad))
4365 error ("Incorrect EH edge %i->%i", bb->index, eh_edge->dest->index);
4372 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4375 verify_eh_dispatch_edge (gimple stmt)
4379 basic_block src, dst;
4380 bool want_fallthru = true;
4384 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
4385 src = gimple_bb (stmt);
4387 FOR_EACH_EDGE (e, ei, src->succs)
4388 gcc_assert (e->aux == NULL);
4393 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
4395 dst = label_to_block (c->label);
4396 e = find_edge (src, dst);
4399 error ("BB %i is missing an edge", src->index);
4404 /* A catch-all handler doesn't have a fallthru. */
4405 if (c->type_list == NULL)
4407 want_fallthru = false;
4413 case ERT_ALLOWED_EXCEPTIONS:
4414 dst = label_to_block (r->u.allowed.label);
4415 e = find_edge (src, dst);
4418 error ("BB %i is missing an edge", src->index);
4429 FOR_EACH_EDGE (e, ei, src->succs)
4431 if (e->flags & EDGE_FALLTHRU)
4433 if (fall_edge != NULL)
4435 error ("BB %i too many fallthru edges", src->index);
4444 error ("BB %i has incorrect edge", src->index);
4448 if ((fall_edge != NULL) ^ want_fallthru)
4450 error ("BB %i has incorrect fallthru edge", src->index);