1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
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"
42 /* In some instances a tree and a gimple need to be stored in a same table,
43 i.e. in hash tables. This is a structure to do this. */
44 typedef union {tree *tp; tree t; gimple g;} treemple;
46 /* Nonzero if we are using EH to handle cleanups. */
47 static int using_eh_for_cleanups_p = 0;
50 using_eh_for_cleanups (void)
52 using_eh_for_cleanups_p = 1;
55 /* Misc functions used in this file. */
57 /* Compare and hash for any structure which begins with a canonical
58 pointer. Assumes all pointers are interchangeable, which is sort
59 of already assumed by gcc elsewhere IIRC. */
62 struct_ptr_eq (const void *a, const void *b)
64 const void * const * x = (const void * const *) a;
65 const void * const * y = (const void * const *) b;
70 struct_ptr_hash (const void *a)
72 const void * const * x = (const void * const *) a;
73 return (size_t)*x >> 4;
77 /* Remember and lookup EH landing pad data for arbitrary statements.
78 Really this means any statement that could_throw_p. We could
79 stuff this information into the stmt_ann data structure, but:
81 (1) We absolutely rely on this information being kept until
82 we get to rtl. Once we're done with lowering here, if we lose
83 the information there's no way to recover it!
85 (2) There are many more statements that *cannot* throw as
86 compared to those that can. We should be saving some amount
87 of space by only allocating memory for those that can throw. */
89 /* Add statement T in function IFUN to landing pad NUM. */
92 add_stmt_to_eh_lp_fn (struct function *ifun, gimple t, int num)
94 struct throw_stmt_node *n;
97 gcc_assert (num != 0);
99 n = GGC_NEW (struct throw_stmt_node);
103 if (!get_eh_throw_stmt_table (ifun))
104 set_eh_throw_stmt_table (ifun, htab_create_ggc (31, struct_ptr_hash,
108 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), n, INSERT);
113 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
116 add_stmt_to_eh_lp (gimple t, int num)
118 add_stmt_to_eh_lp_fn (cfun, t, num);
121 /* Add statement T to the single EH landing pad in REGION. */
124 record_stmt_eh_region (eh_region region, gimple t)
128 if (region->type == ERT_MUST_NOT_THROW)
129 add_stmt_to_eh_lp_fn (cfun, t, -region->index);
132 eh_landing_pad lp = region->landing_pads;
134 lp = gen_eh_landing_pad (region);
136 gcc_assert (lp->next_lp == NULL);
137 add_stmt_to_eh_lp_fn (cfun, t, lp->index);
142 /* Remove statement T in function IFUN from its EH landing pad. */
145 remove_stmt_from_eh_lp_fn (struct function *ifun, gimple t)
147 struct throw_stmt_node dummy;
150 if (!get_eh_throw_stmt_table (ifun))
154 slot = htab_find_slot (get_eh_throw_stmt_table (ifun), &dummy,
158 htab_clear_slot (get_eh_throw_stmt_table (ifun), slot);
166 /* Remove statement T in the current function (cfun) from its
170 remove_stmt_from_eh_lp (gimple t)
172 return remove_stmt_from_eh_lp_fn (cfun, t);
175 /* Determine if statement T is inside an EH region in function IFUN.
176 Positive numbers indicate a landing pad index; negative numbers
177 indicate a MUST_NOT_THROW region index; zero indicates that the
178 statement is not recorded in the region table. */
181 lookup_stmt_eh_lp_fn (struct function *ifun, gimple t)
183 struct throw_stmt_node *p, n;
185 if (ifun->eh->throw_stmt_table == NULL)
189 p = (struct throw_stmt_node *) htab_find (ifun->eh->throw_stmt_table, &n);
190 return p ? p->lp_nr : 0;
193 /* Likewise, but always use the current function. */
196 lookup_stmt_eh_lp (gimple t)
198 /* We can get called from initialized data when -fnon-call-exceptions
199 is on; prevent crash. */
202 return lookup_stmt_eh_lp_fn (cfun, t);
205 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
206 nodes and LABEL_DECL nodes. We will use this during the second phase to
207 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
209 struct finally_tree_node
211 /* When storing a GIMPLE_TRY, we have to record a gimple. However
212 when deciding whether a GOTO to a certain LABEL_DECL (which is a
213 tree) leaves the TRY block, its necessary to record a tree in
214 this field. Thus a treemple is used. */
219 /* Note that this table is *not* marked GTY. It is short-lived. */
220 static htab_t finally_tree;
223 record_in_finally_tree (treemple child, gimple parent)
225 struct finally_tree_node *n;
228 n = XNEW (struct finally_tree_node);
232 slot = htab_find_slot (finally_tree, n, INSERT);
238 collect_finally_tree (gimple stmt, gimple region);
240 /* Go through the gimple sequence. Works with collect_finally_tree to
241 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
244 collect_finally_tree_1 (gimple_seq seq, gimple region)
246 gimple_stmt_iterator gsi;
248 for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi))
249 collect_finally_tree (gsi_stmt (gsi), region);
253 collect_finally_tree (gimple stmt, gimple region)
257 switch (gimple_code (stmt))
260 temp.t = gimple_label_label (stmt);
261 record_in_finally_tree (temp, region);
265 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
268 record_in_finally_tree (temp, region);
269 collect_finally_tree_1 (gimple_try_eval (stmt), stmt);
270 collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
272 else if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH)
274 collect_finally_tree_1 (gimple_try_eval (stmt), region);
275 collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
280 collect_finally_tree_1 (gimple_catch_handler (stmt), region);
283 case GIMPLE_EH_FILTER:
284 collect_finally_tree_1 (gimple_eh_filter_failure (stmt), region);
288 /* A type, a decl, or some kind of statement that we're not
289 interested in. Don't walk them. */
295 /* Use the finally tree to determine if a jump from START to TARGET
296 would leave the try_finally node that START lives in. */
299 outside_finally_tree (treemple start, gimple target)
301 struct finally_tree_node n, *p;
306 p = (struct finally_tree_node *) htab_find (finally_tree, &n);
311 while (start.g != target);
316 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
317 nodes into a set of gotos, magic labels, and eh regions.
318 The eh region creation is straight-forward, but frobbing all the gotos
319 and such into shape isn't. */
321 /* The sequence into which we record all EH stuff. This will be
322 placed at the end of the function when we're all done. */
323 static gimple_seq eh_seq;
325 /* Record whether an EH region contains something that can throw,
326 indexed by EH region number. */
327 static bitmap eh_region_may_contain_throw_map;
329 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
330 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
331 The idea is to record a gimple statement for everything except for
332 the conditionals, which get their labels recorded. Since labels are
333 of type 'tree', we need this node to store both gimple and tree
334 objects. REPL_STMT is the sequence used to replace the goto/return
335 statement. CONT_STMT is used to store the statement that allows
336 the return/goto to jump to the original destination. */
338 struct goto_queue_node
341 gimple_seq repl_stmt;
344 /* This is used when index >= 0 to indicate that stmt is a label (as
345 opposed to a goto stmt). */
349 /* State of the world while lowering. */
353 /* What's "current" while constructing the eh region tree. These
354 correspond to variables of the same name in cfun->eh, which we
355 don't have easy access to. */
356 eh_region cur_region;
358 /* What's "current" for the purposes of __builtin_eh_pointer. For
359 a CATCH, this is the associated TRY. For an EH_FILTER, this is
360 the associated ALLOWED_EXCEPTIONS, etc. */
361 eh_region ehp_region;
363 /* Processing of TRY_FINALLY requires a bit more state. This is
364 split out into a separate structure so that we don't have to
365 copy so much when processing other nodes. */
366 struct leh_tf_state *tf;
371 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
372 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
373 this so that outside_finally_tree can reliably reference the tree used
374 in the collect_finally_tree data structures. */
375 gimple try_finally_expr;
378 /* While lowering a top_p usually it is expanded into multiple statements,
379 thus we need the following field to store them. */
380 gimple_seq top_p_seq;
382 /* The state outside this try_finally node. */
383 struct leh_state *outer;
385 /* The exception region created for it. */
388 /* The goto queue. */
389 struct goto_queue_node *goto_queue;
390 size_t goto_queue_size;
391 size_t goto_queue_active;
393 /* Pointer map to help in searching goto_queue when it is large. */
394 struct pointer_map_t *goto_queue_map;
396 /* The set of unique labels seen as entries in the goto queue. */
397 VEC(tree,heap) *dest_array;
399 /* A label to be added at the end of the completed transformed
400 sequence. It will be set if may_fallthru was true *at one time*,
401 though subsequent transformations may have cleared that flag. */
404 /* True if it is possible to fall out the bottom of the try block.
405 Cleared if the fallthru is converted to a goto. */
408 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
411 /* True if the finally block can receive an exception edge.
412 Cleared if the exception case is handled by code duplication. */
416 static gimple_seq lower_eh_must_not_throw (struct leh_state *, gimple);
418 /* Search for STMT in the goto queue. Return the replacement,
419 or null if the statement isn't in the queue. */
421 #define LARGE_GOTO_QUEUE 20
423 static void lower_eh_constructs_1 (struct leh_state *state, gimple_seq seq);
426 find_goto_replacement (struct leh_tf_state *tf, treemple stmt)
431 if (tf->goto_queue_active < LARGE_GOTO_QUEUE)
433 for (i = 0; i < tf->goto_queue_active; i++)
434 if ( tf->goto_queue[i].stmt.g == stmt.g)
435 return tf->goto_queue[i].repl_stmt;
439 /* If we have a large number of entries in the goto_queue, create a
440 pointer map and use that for searching. */
442 if (!tf->goto_queue_map)
444 tf->goto_queue_map = pointer_map_create ();
445 for (i = 0; i < tf->goto_queue_active; i++)
447 slot = pointer_map_insert (tf->goto_queue_map,
448 tf->goto_queue[i].stmt.g);
449 gcc_assert (*slot == NULL);
450 *slot = &tf->goto_queue[i];
454 slot = pointer_map_contains (tf->goto_queue_map, stmt.g);
456 return (((struct goto_queue_node *) *slot)->repl_stmt);
461 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
462 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
463 then we can just splat it in, otherwise we add the new stmts immediately
464 after the GIMPLE_COND and redirect. */
467 replace_goto_queue_cond_clause (tree *tp, struct leh_tf_state *tf,
468 gimple_stmt_iterator *gsi)
473 location_t loc = gimple_location (gsi_stmt (*gsi));
476 new_seq = find_goto_replacement (tf, temp);
480 if (gimple_seq_singleton_p (new_seq)
481 && gimple_code (gimple_seq_first_stmt (new_seq)) == GIMPLE_GOTO)
483 *tp = gimple_goto_dest (gimple_seq_first_stmt (new_seq));
487 label = create_artificial_label (loc);
488 /* Set the new label for the GIMPLE_COND */
491 gsi_insert_after (gsi, gimple_build_label (label), GSI_CONTINUE_LINKING);
492 gsi_insert_seq_after (gsi, gimple_seq_copy (new_seq), GSI_CONTINUE_LINKING);
495 /* The real work of replace_goto_queue. Returns with TSI updated to
496 point to the next statement. */
498 static void replace_goto_queue_stmt_list (gimple_seq, struct leh_tf_state *);
501 replace_goto_queue_1 (gimple stmt, struct leh_tf_state *tf,
502 gimple_stmt_iterator *gsi)
508 switch (gimple_code (stmt))
513 seq = find_goto_replacement (tf, temp);
516 gsi_insert_seq_before (gsi, gimple_seq_copy (seq), GSI_SAME_STMT);
517 gsi_remove (gsi, false);
523 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 2), tf, gsi);
524 replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 3), tf, gsi);
528 replace_goto_queue_stmt_list (gimple_try_eval (stmt), tf);
529 replace_goto_queue_stmt_list (gimple_try_cleanup (stmt), tf);
532 replace_goto_queue_stmt_list (gimple_catch_handler (stmt), tf);
534 case GIMPLE_EH_FILTER:
535 replace_goto_queue_stmt_list (gimple_eh_filter_failure (stmt), tf);
539 /* These won't have gotos in them. */
546 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
549 replace_goto_queue_stmt_list (gimple_seq seq, struct leh_tf_state *tf)
551 gimple_stmt_iterator gsi = gsi_start (seq);
553 while (!gsi_end_p (gsi))
554 replace_goto_queue_1 (gsi_stmt (gsi), tf, &gsi);
557 /* Replace all goto queue members. */
560 replace_goto_queue (struct leh_tf_state *tf)
562 if (tf->goto_queue_active == 0)
564 replace_goto_queue_stmt_list (tf->top_p_seq, tf);
565 replace_goto_queue_stmt_list (eh_seq, tf);
568 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
569 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
573 record_in_goto_queue (struct leh_tf_state *tf,
579 struct goto_queue_node *q;
581 gcc_assert (!tf->goto_queue_map);
583 active = tf->goto_queue_active;
584 size = tf->goto_queue_size;
587 size = (size ? size * 2 : 32);
588 tf->goto_queue_size = size;
590 = XRESIZEVEC (struct goto_queue_node, tf->goto_queue, size);
593 q = &tf->goto_queue[active];
594 tf->goto_queue_active = active + 1;
596 memset (q, 0, sizeof (*q));
599 q->is_label = is_label;
602 /* Record the LABEL label in the goto queue contained in TF.
606 record_in_goto_queue_label (struct leh_tf_state *tf, treemple stmt, tree label)
609 treemple temp, new_stmt;
614 /* Computed and non-local gotos do not get processed. Given
615 their nature we can neither tell whether we've escaped the
616 finally block nor redirect them if we knew. */
617 if (TREE_CODE (label) != LABEL_DECL)
620 /* No need to record gotos that don't leave the try block. */
622 if (!outside_finally_tree (temp, tf->try_finally_expr))
625 if (! tf->dest_array)
627 tf->dest_array = VEC_alloc (tree, heap, 10);
628 VEC_quick_push (tree, tf->dest_array, label);
633 int n = VEC_length (tree, tf->dest_array);
634 for (index = 0; index < n; ++index)
635 if (VEC_index (tree, tf->dest_array, index) == label)
638 VEC_safe_push (tree, heap, tf->dest_array, label);
641 /* In the case of a GOTO we want to record the destination label,
642 since with a GIMPLE_COND we have an easy access to the then/else
645 record_in_goto_queue (tf, new_stmt, index, true);
648 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
649 node, and if so record that fact in the goto queue associated with that
653 maybe_record_in_goto_queue (struct leh_state *state, gimple stmt)
655 struct leh_tf_state *tf = state->tf;
661 switch (gimple_code (stmt))
664 new_stmt.tp = gimple_op_ptr (stmt, 2);
665 record_in_goto_queue_label (tf, new_stmt, gimple_cond_true_label (stmt));
666 new_stmt.tp = gimple_op_ptr (stmt, 3);
667 record_in_goto_queue_label (tf, new_stmt, gimple_cond_false_label (stmt));
671 record_in_goto_queue_label (tf, new_stmt, gimple_goto_dest (stmt));
675 tf->may_return = true;
677 record_in_goto_queue (tf, new_stmt, -1, false);
686 #ifdef ENABLE_CHECKING
687 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
688 was in fact structured, and we've not yet done jump threading, then none
689 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
692 verify_norecord_switch_expr (struct leh_state *state, gimple switch_expr)
694 struct leh_tf_state *tf = state->tf;
700 n = gimple_switch_num_labels (switch_expr);
702 for (i = 0; i < n; ++i)
705 tree lab = CASE_LABEL (gimple_switch_label (switch_expr, i));
707 gcc_assert (!outside_finally_tree (temp, tf->try_finally_expr));
711 #define verify_norecord_switch_expr(state, switch_expr)
714 /* Redirect a RETURN_EXPR pointed to by STMT_P to FINLAB. Place in CONT_P
715 whatever is needed to finish the return. If MOD is non-null, insert it
716 before the new branch. RETURN_VALUE_P is a cache containing a temporary
717 variable to be used in manipulating the value returned from the function. */
720 do_return_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod,
721 tree *return_value_p)
726 /* In the case of a return, the queue node must be a gimple statement. */
727 gcc_assert (!q->is_label);
729 ret_expr = gimple_return_retval (q->stmt.g);
733 if (!*return_value_p)
734 *return_value_p = ret_expr;
736 gcc_assert (*return_value_p == ret_expr);
737 q->cont_stmt = q->stmt.g;
738 /* The nasty part about redirecting the return value is that the
739 return value itself is to be computed before the FINALLY block
753 should return 0, not 1. Arrange for this to happen by copying
754 computed the return value into a local temporary. This also
755 allows us to redirect multiple return statements through the
756 same destination block; whether this is a net win or not really
757 depends, I guess, but it does make generation of the switch in
758 lower_try_finally_switch easier. */
760 if (TREE_CODE (ret_expr) == RESULT_DECL)
762 if (!*return_value_p)
763 *return_value_p = ret_expr;
765 gcc_assert (*return_value_p == ret_expr);
766 q->cont_stmt = q->stmt.g;
772 /* If we don't return a value, all return statements are the same. */
773 q->cont_stmt = q->stmt.g;
776 q->repl_stmt = gimple_seq_alloc ();
779 gimple_seq_add_seq (&q->repl_stmt, mod);
781 x = gimple_build_goto (finlab);
782 gimple_seq_add_stmt (&q->repl_stmt, x);
785 /* Similar, but easier, for GIMPLE_GOTO. */
788 do_goto_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod,
789 struct leh_tf_state *tf)
793 gcc_assert (q->is_label);
795 q->repl_stmt = gimple_seq_alloc ();
797 q->cont_stmt = gimple_build_goto (VEC_index (tree, tf->dest_array, q->index));
800 gimple_seq_add_seq (&q->repl_stmt, mod);
802 x = gimple_build_goto (finlab);
803 gimple_seq_add_stmt (&q->repl_stmt, x);
806 /* Emit a standard landing pad sequence into SEQ for REGION. */
809 emit_post_landing_pad (gimple_seq *seq, eh_region region)
811 eh_landing_pad lp = region->landing_pads;
815 lp = gen_eh_landing_pad (region);
817 lp->post_landing_pad = create_artificial_label (UNKNOWN_LOCATION);
818 EH_LANDING_PAD_NR (lp->post_landing_pad) = lp->index;
820 x = gimple_build_label (lp->post_landing_pad);
821 gimple_seq_add_stmt (seq, x);
824 /* Emit a RESX statement into SEQ for REGION. */
827 emit_resx (gimple_seq *seq, eh_region region)
829 gimple x = gimple_build_resx (region->index);
830 gimple_seq_add_stmt (seq, x);
832 record_stmt_eh_region (region->outer, x);
835 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
838 emit_eh_dispatch (gimple_seq *seq, eh_region region)
840 gimple x = gimple_build_eh_dispatch (region->index);
841 gimple_seq_add_stmt (seq, x);
844 /* Note that the current EH region may contain a throw, or a
845 call to a function which itself may contain a throw. */
848 note_eh_region_may_contain_throw (eh_region region)
850 while (!bitmap_bit_p (eh_region_may_contain_throw_map, region->index))
852 bitmap_set_bit (eh_region_may_contain_throw_map, region->index);
853 region = region->outer;
859 /* Check if REGION has been marked as containing a throw. If REGION is
860 NULL, this predicate is false. */
863 eh_region_may_contain_throw (eh_region r)
865 return r && bitmap_bit_p (eh_region_may_contain_throw_map, r->index);
868 /* We want to transform
869 try { body; } catch { stuff; }
879 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
880 should be placed before the second operand, or NULL. OVER is
881 an existing label that should be put at the exit, or NULL. */
884 frob_into_branch_around (gimple tp, eh_region region, tree over)
887 gimple_seq cleanup, result;
888 location_t loc = gimple_location (tp);
890 cleanup = gimple_try_cleanup (tp);
891 result = gimple_try_eval (tp);
894 emit_post_landing_pad (&eh_seq, region);
896 if (gimple_seq_may_fallthru (cleanup))
899 over = create_artificial_label (loc);
900 x = gimple_build_goto (over);
901 gimple_seq_add_stmt (&cleanup, x);
903 gimple_seq_add_seq (&eh_seq, cleanup);
907 x = gimple_build_label (over);
908 gimple_seq_add_stmt (&result, x);
913 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
914 Make sure to record all new labels found. */
917 lower_try_finally_dup_block (gimple_seq seq, struct leh_state *outer_state)
919 gimple region = NULL;
922 new_seq = copy_gimple_seq_and_replace_locals (seq);
925 region = outer_state->tf->try_finally_expr;
926 collect_finally_tree_1 (new_seq, region);
931 /* A subroutine of lower_try_finally. Create a fallthru label for
932 the given try_finally state. The only tricky bit here is that
933 we have to make sure to record the label in our outer context. */
936 lower_try_finally_fallthru_label (struct leh_tf_state *tf)
938 tree label = tf->fallthru_label;
943 label = create_artificial_label (gimple_location (tf->try_finally_expr));
944 tf->fallthru_label = label;
948 record_in_finally_tree (temp, tf->outer->tf->try_finally_expr);
954 /* A subroutine of lower_try_finally. If lang_protect_cleanup_actions
955 returns non-null, then the language requires that the exception path out
956 of a try_finally be treated specially. To wit: the code within the
957 finally block may not itself throw an exception. We have two choices here.
958 First we can duplicate the finally block and wrap it in a must_not_throw
959 region. Second, we can generate code like
964 if (fintmp == eh_edge)
965 protect_cleanup_actions;
968 where "fintmp" is the temporary used in the switch statement generation
969 alternative considered below. For the nonce, we always choose the first
972 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
975 honor_protect_cleanup_actions (struct leh_state *outer_state,
976 struct leh_state *this_state,
977 struct leh_tf_state *tf)
979 tree protect_cleanup_actions;
980 gimple_stmt_iterator gsi;
981 bool finally_may_fallthru;
985 /* First check for nothing to do. */
986 if (lang_protect_cleanup_actions == NULL)
988 protect_cleanup_actions = lang_protect_cleanup_actions ();
989 if (protect_cleanup_actions == NULL)
992 finally = gimple_try_cleanup (tf->top_p);
993 finally_may_fallthru = gimple_seq_may_fallthru (finally);
995 /* Duplicate the FINALLY block. Only need to do this for try-finally,
996 and not for cleanups. */
998 finally = lower_try_finally_dup_block (finally, outer_state);
1000 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1001 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1002 to be in an enclosing scope, but needs to be implemented at this level
1003 to avoid a nesting violation (see wrap_temporary_cleanups in
1004 cp/decl.c). Since it's logically at an outer level, we should call
1005 terminate before we get to it, so strip it away before adding the
1006 MUST_NOT_THROW filter. */
1007 gsi = gsi_start (finally);
1009 if (gimple_code (x) == GIMPLE_TRY
1010 && gimple_try_kind (x) == GIMPLE_TRY_CATCH
1011 && gimple_try_catch_is_cleanup (x))
1013 gsi_insert_seq_before (&gsi, gimple_try_eval (x), GSI_SAME_STMT);
1014 gsi_remove (&gsi, false);
1017 /* Wrap the block with protect_cleanup_actions as the action. */
1018 x = gimple_build_eh_must_not_throw (protect_cleanup_actions);
1019 x = gimple_build_try (finally, gimple_seq_alloc_with_stmt (x),
1021 finally = lower_eh_must_not_throw (outer_state, x);
1023 /* Drop all of this into the exception sequence. */
1024 emit_post_landing_pad (&eh_seq, tf->region);
1025 gimple_seq_add_seq (&eh_seq, finally);
1026 if (finally_may_fallthru)
1027 emit_resx (&eh_seq, tf->region);
1029 /* Having now been handled, EH isn't to be considered with
1030 the rest of the outgoing edges. */
1031 tf->may_throw = false;
1034 /* A subroutine of lower_try_finally. We have determined that there is
1035 no fallthru edge out of the finally block. This means that there is
1036 no outgoing edge corresponding to any incoming edge. Restructure the
1037 try_finally node for this special case. */
1040 lower_try_finally_nofallthru (struct leh_state *state,
1041 struct leh_tf_state *tf)
1043 tree lab, return_val;
1046 struct goto_queue_node *q, *qe;
1048 lab = create_artificial_label (gimple_location (tf->try_finally_expr));
1050 /* We expect that tf->top_p is a GIMPLE_TRY. */
1051 finally = gimple_try_cleanup (tf->top_p);
1052 tf->top_p_seq = gimple_try_eval (tf->top_p);
1054 x = gimple_build_label (lab);
1055 gimple_seq_add_stmt (&tf->top_p_seq, x);
1059 qe = q + tf->goto_queue_active;
1062 do_return_redirection (q, lab, NULL, &return_val);
1064 do_goto_redirection (q, lab, NULL, tf);
1066 replace_goto_queue (tf);
1068 lower_eh_constructs_1 (state, finally);
1069 gimple_seq_add_seq (&tf->top_p_seq, finally);
1073 emit_post_landing_pad (&eh_seq, tf->region);
1075 x = gimple_build_goto (lab);
1076 gimple_seq_add_stmt (&eh_seq, x);
1080 /* A subroutine of lower_try_finally. We have determined that there is
1081 exactly one destination of the finally block. Restructure the
1082 try_finally node for this special case. */
1085 lower_try_finally_onedest (struct leh_state *state, struct leh_tf_state *tf)
1087 struct goto_queue_node *q, *qe;
1091 location_t loc = gimple_location (tf->try_finally_expr);
1093 finally = gimple_try_cleanup (tf->top_p);
1094 tf->top_p_seq = gimple_try_eval (tf->top_p);
1096 lower_eh_constructs_1 (state, finally);
1100 /* Only reachable via the exception edge. Add the given label to
1101 the head of the FINALLY block. Append a RESX at the end. */
1102 emit_post_landing_pad (&eh_seq, tf->region);
1103 gimple_seq_add_seq (&eh_seq, finally);
1104 emit_resx (&eh_seq, tf->region);
1108 if (tf->may_fallthru)
1110 /* Only reachable via the fallthru edge. Do nothing but let
1111 the two blocks run together; we'll fall out the bottom. */
1112 gimple_seq_add_seq (&tf->top_p_seq, finally);
1116 finally_label = create_artificial_label (loc);
1117 x = gimple_build_label (finally_label);
1118 gimple_seq_add_stmt (&tf->top_p_seq, x);
1120 gimple_seq_add_seq (&tf->top_p_seq, finally);
1123 qe = q + tf->goto_queue_active;
1127 /* Reachable by return expressions only. Redirect them. */
1128 tree return_val = NULL;
1130 do_return_redirection (q, finally_label, NULL, &return_val);
1131 replace_goto_queue (tf);
1135 /* Reachable by goto expressions only. Redirect them. */
1137 do_goto_redirection (q, finally_label, NULL, tf);
1138 replace_goto_queue (tf);
1140 if (VEC_index (tree, tf->dest_array, 0) == tf->fallthru_label)
1142 /* Reachable by goto to fallthru label only. Redirect it
1143 to the new label (already created, sadly), and do not
1144 emit the final branch out, or the fallthru label. */
1145 tf->fallthru_label = NULL;
1150 /* Place the original return/goto to the original destination
1151 immediately after the finally block. */
1152 x = tf->goto_queue[0].cont_stmt;
1153 gimple_seq_add_stmt (&tf->top_p_seq, x);
1154 maybe_record_in_goto_queue (state, x);
1157 /* A subroutine of lower_try_finally. There are multiple edges incoming
1158 and outgoing from the finally block. Implement this by duplicating the
1159 finally block for every destination. */
1162 lower_try_finally_copy (struct leh_state *state, struct leh_tf_state *tf)
1165 gimple_seq new_stmt;
1169 location_t tf_loc = gimple_location (tf->try_finally_expr);
1171 finally = gimple_try_cleanup (tf->top_p);
1172 tf->top_p_seq = gimple_try_eval (tf->top_p);
1175 if (tf->may_fallthru)
1177 seq = lower_try_finally_dup_block (finally, state);
1178 lower_eh_constructs_1 (state, seq);
1179 gimple_seq_add_seq (&new_stmt, seq);
1181 tmp = lower_try_finally_fallthru_label (tf);
1182 x = gimple_build_goto (tmp);
1183 gimple_seq_add_stmt (&new_stmt, x);
1188 seq = lower_try_finally_dup_block (finally, state);
1189 lower_eh_constructs_1 (state, seq);
1191 emit_post_landing_pad (&eh_seq, tf->region);
1192 gimple_seq_add_seq (&eh_seq, seq);
1193 emit_resx (&eh_seq, tf->region);
1198 struct goto_queue_node *q, *qe;
1199 tree return_val = NULL;
1200 int return_index, index;
1203 struct goto_queue_node *q;
1207 return_index = VEC_length (tree, tf->dest_array);
1208 labels = XCNEWVEC (struct labels_s, return_index + 1);
1211 qe = q + tf->goto_queue_active;
1214 index = q->index < 0 ? return_index : q->index;
1216 if (!labels[index].q)
1217 labels[index].q = q;
1220 for (index = 0; index < return_index + 1; index++)
1224 q = labels[index].q;
1228 lab = labels[index].label
1229 = create_artificial_label (tf_loc);
1231 if (index == return_index)
1232 do_return_redirection (q, lab, NULL, &return_val);
1234 do_goto_redirection (q, lab, NULL, tf);
1236 x = gimple_build_label (lab);
1237 gimple_seq_add_stmt (&new_stmt, x);
1239 seq = lower_try_finally_dup_block (finally, state);
1240 lower_eh_constructs_1 (state, seq);
1241 gimple_seq_add_seq (&new_stmt, seq);
1243 gimple_seq_add_stmt (&new_stmt, q->cont_stmt);
1244 maybe_record_in_goto_queue (state, q->cont_stmt);
1247 for (q = tf->goto_queue; q < qe; q++)
1251 index = q->index < 0 ? return_index : q->index;
1253 if (labels[index].q == q)
1256 lab = labels[index].label;
1258 if (index == return_index)
1259 do_return_redirection (q, lab, NULL, &return_val);
1261 do_goto_redirection (q, lab, NULL, tf);
1264 replace_goto_queue (tf);
1268 /* Need to link new stmts after running replace_goto_queue due
1269 to not wanting to process the same goto stmts twice. */
1270 gimple_seq_add_seq (&tf->top_p_seq, new_stmt);
1273 /* A subroutine of lower_try_finally. There are multiple edges incoming
1274 and outgoing from the finally block. Implement this by instrumenting
1275 each incoming edge and creating a switch statement at the end of the
1276 finally block that branches to the appropriate destination. */
1279 lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf)
1281 struct goto_queue_node *q, *qe;
1282 tree return_val = NULL;
1283 tree finally_tmp, finally_label;
1284 int return_index, eh_index, fallthru_index;
1285 int nlabels, ndests, j, last_case_index;
1287 VEC (tree,heap) *case_label_vec;
1288 gimple_seq switch_body;
1293 struct pointer_map_t *cont_map = NULL;
1294 /* The location of the TRY_FINALLY stmt. */
1295 location_t tf_loc = gimple_location (tf->try_finally_expr);
1296 /* The location of the finally block. */
1297 location_t finally_loc;
1299 switch_body = gimple_seq_alloc ();
1301 /* Mash the TRY block to the head of the chain. */
1302 finally = gimple_try_cleanup (tf->top_p);
1303 tf->top_p_seq = gimple_try_eval (tf->top_p);
1305 /* The location of the finally is either the last stmt in the finally
1306 block or the location of the TRY_FINALLY itself. */
1307 finally_loc = gimple_seq_last_stmt (tf->top_p_seq) != NULL ?
1308 gimple_location (gimple_seq_last_stmt (tf->top_p_seq))
1311 /* Lower the finally block itself. */
1312 lower_eh_constructs_1 (state, finally);
1314 /* Prepare for switch statement generation. */
1315 nlabels = VEC_length (tree, tf->dest_array);
1316 return_index = nlabels;
1317 eh_index = return_index + tf->may_return;
1318 fallthru_index = eh_index + tf->may_throw;
1319 ndests = fallthru_index + tf->may_fallthru;
1321 finally_tmp = create_tmp_var (integer_type_node, "finally_tmp");
1322 finally_label = create_artificial_label (finally_loc);
1324 /* We use VEC_quick_push on case_label_vec throughout this function,
1325 since we know the size in advance and allocate precisely as muce
1327 case_label_vec = VEC_alloc (tree, heap, ndests);
1329 last_case_index = 0;
1331 /* Begin inserting code for getting to the finally block. Things
1332 are done in this order to correspond to the sequence the code is
1335 if (tf->may_fallthru)
1337 x = gimple_build_assign (finally_tmp,
1338 build_int_cst (NULL, fallthru_index));
1339 gimple_seq_add_stmt (&tf->top_p_seq, x);
1341 last_case = build3 (CASE_LABEL_EXPR, void_type_node,
1342 build_int_cst (NULL, fallthru_index),
1343 NULL, create_artificial_label (tf_loc));
1344 VEC_quick_push (tree, case_label_vec, last_case);
1347 x = gimple_build_label (CASE_LABEL (last_case));
1348 gimple_seq_add_stmt (&switch_body, x);
1350 tmp = lower_try_finally_fallthru_label (tf);
1351 x = gimple_build_goto (tmp);
1352 gimple_seq_add_stmt (&switch_body, x);
1357 emit_post_landing_pad (&eh_seq, tf->region);
1359 x = gimple_build_assign (finally_tmp,
1360 build_int_cst (NULL, eh_index));
1361 gimple_seq_add_stmt (&eh_seq, x);
1363 x = gimple_build_goto (finally_label);
1364 gimple_seq_add_stmt (&eh_seq, x);
1366 last_case = build3 (CASE_LABEL_EXPR, void_type_node,
1367 build_int_cst (NULL, eh_index),
1368 NULL, create_artificial_label (tf_loc));
1369 VEC_quick_push (tree, case_label_vec, last_case);
1372 x = gimple_build_label (CASE_LABEL (last_case));
1373 gimple_seq_add_stmt (&eh_seq, x);
1374 emit_resx (&eh_seq, tf->region);
1377 x = gimple_build_label (finally_label);
1378 gimple_seq_add_stmt (&tf->top_p_seq, x);
1380 gimple_seq_add_seq (&tf->top_p_seq, finally);
1382 /* Redirect each incoming goto edge. */
1384 qe = q + tf->goto_queue_active;
1385 j = last_case_index + tf->may_return;
1386 /* Prepare the assignments to finally_tmp that are executed upon the
1387 entrance through a particular edge. */
1392 unsigned int case_index;
1394 mod = gimple_seq_alloc ();
1398 x = gimple_build_assign (finally_tmp,
1399 build_int_cst (NULL, return_index));
1400 gimple_seq_add_stmt (&mod, x);
1401 do_return_redirection (q, finally_label, mod, &return_val);
1402 switch_id = return_index;
1406 x = gimple_build_assign (finally_tmp,
1407 build_int_cst (NULL, q->index));
1408 gimple_seq_add_stmt (&mod, x);
1409 do_goto_redirection (q, finally_label, mod, tf);
1410 switch_id = q->index;
1413 case_index = j + q->index;
1414 if (VEC_length (tree, case_label_vec) <= case_index
1415 || !VEC_index (tree, case_label_vec, case_index))
1419 case_lab = build3 (CASE_LABEL_EXPR, void_type_node,
1420 build_int_cst (NULL, switch_id),
1422 /* We store the cont_stmt in the pointer map, so that we can recover
1423 it in the loop below. We don't create the new label while
1424 walking the goto_queue because pointers don't offer a stable
1427 cont_map = pointer_map_create ();
1428 slot = pointer_map_insert (cont_map, case_lab);
1429 *slot = q->cont_stmt;
1430 VEC_quick_push (tree, case_label_vec, case_lab);
1433 for (j = last_case_index; j < last_case_index + nlabels; j++)
1439 last_case = VEC_index (tree, case_label_vec, j);
1441 gcc_assert (last_case);
1442 gcc_assert (cont_map);
1444 slot = pointer_map_contains (cont_map, last_case);
1445 /* As the comment above suggests, CASE_LABEL (last_case) was just a
1446 placeholder, it does not store an actual label, yet. */
1448 cont_stmt = *(gimple *) slot;
1450 label = create_artificial_label (tf_loc);
1451 CASE_LABEL (last_case) = label;
1453 x = gimple_build_label (label);
1454 gimple_seq_add_stmt (&switch_body, x);
1455 gimple_seq_add_stmt (&switch_body, cont_stmt);
1456 maybe_record_in_goto_queue (state, cont_stmt);
1459 pointer_map_destroy (cont_map);
1461 replace_goto_queue (tf);
1463 /* Make sure that the last case is the default label, as one is required.
1464 Then sort the labels, which is also required in GIMPLE. */
1465 CASE_LOW (last_case) = NULL;
1466 sort_case_labels (case_label_vec);
1468 /* Build the switch statement, setting last_case to be the default
1470 switch_stmt = gimple_build_switch_vec (finally_tmp, last_case,
1472 gimple_set_location (switch_stmt, finally_loc);
1474 /* Need to link SWITCH_STMT after running replace_goto_queue
1475 due to not wanting to process the same goto stmts twice. */
1476 gimple_seq_add_stmt (&tf->top_p_seq, switch_stmt);
1477 gimple_seq_add_seq (&tf->top_p_seq, switch_body);
1480 /* Decide whether or not we are going to duplicate the finally block.
1481 There are several considerations.
1483 First, if this is Java, then the finally block contains code
1484 written by the user. It has line numbers associated with it,
1485 so duplicating the block means it's difficult to set a breakpoint.
1486 Since controlling code generation via -g is verboten, we simply
1487 never duplicate code without optimization.
1489 Second, we'd like to prevent egregious code growth. One way to
1490 do this is to estimate the size of the finally block, multiply
1491 that by the number of copies we'd need to make, and compare against
1492 the estimate of the size of the switch machinery we'd have to add. */
1495 decide_copy_try_finally (int ndests, gimple_seq finally)
1497 int f_estimate, sw_estimate;
1502 /* Finally estimate N times, plus N gotos. */
1503 f_estimate = count_insns_seq (finally, &eni_size_weights);
1504 f_estimate = (f_estimate + 1) * ndests;
1506 /* Switch statement (cost 10), N variable assignments, N gotos. */
1507 sw_estimate = 10 + 2 * ndests;
1509 /* Optimize for size clearly wants our best guess. */
1510 if (optimize_function_for_size_p (cfun))
1511 return f_estimate < sw_estimate;
1513 /* ??? These numbers are completely made up so far. */
1515 return f_estimate < 100 || f_estimate < sw_estimate * 2;
1517 return f_estimate < 40 || f_estimate * 2 < sw_estimate * 3;
1521 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1522 to a sequence of labels and blocks, plus the exception region trees
1523 that record all the magic. This is complicated by the need to
1524 arrange for the FINALLY block to be executed on all exits. */
1527 lower_try_finally (struct leh_state *state, gimple tp)
1529 struct leh_tf_state this_tf;
1530 struct leh_state this_state;
1532 gimple_seq old_eh_seq;
1534 /* Process the try block. */
1536 memset (&this_tf, 0, sizeof (this_tf));
1537 this_tf.try_finally_expr = tp;
1539 this_tf.outer = state;
1540 if (using_eh_for_cleanups_p)
1541 this_tf.region = gen_eh_region_cleanup (state->cur_region);
1543 this_tf.region = NULL;
1545 this_state.cur_region = this_tf.region;
1546 this_state.ehp_region = state->ehp_region;
1547 this_state.tf = &this_tf;
1549 old_eh_seq = eh_seq;
1552 lower_eh_constructs_1 (&this_state, gimple_try_eval(tp));
1554 /* Determine if the try block is escaped through the bottom. */
1555 this_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
1557 /* Determine if any exceptions are possible within the try block. */
1558 if (using_eh_for_cleanups_p)
1559 this_tf.may_throw = eh_region_may_contain_throw (this_tf.region);
1560 if (this_tf.may_throw)
1561 honor_protect_cleanup_actions (state, &this_state, &this_tf);
1563 /* Determine how many edges (still) reach the finally block. Or rather,
1564 how many destinations are reached by the finally block. Use this to
1565 determine how we process the finally block itself. */
1567 ndests = VEC_length (tree, this_tf.dest_array);
1568 ndests += this_tf.may_fallthru;
1569 ndests += this_tf.may_return;
1570 ndests += this_tf.may_throw;
1572 /* If the FINALLY block is not reachable, dike it out. */
1575 gimple_seq_add_seq (&this_tf.top_p_seq, gimple_try_eval (tp));
1576 gimple_try_set_cleanup (tp, NULL);
1578 /* If the finally block doesn't fall through, then any destination
1579 we might try to impose there isn't reached either. There may be
1580 some minor amount of cleanup and redirection still needed. */
1581 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp)))
1582 lower_try_finally_nofallthru (state, &this_tf);
1584 /* We can easily special-case redirection to a single destination. */
1585 else if (ndests == 1)
1586 lower_try_finally_onedest (state, &this_tf);
1587 else if (decide_copy_try_finally (ndests, gimple_try_cleanup (tp)))
1588 lower_try_finally_copy (state, &this_tf);
1590 lower_try_finally_switch (state, &this_tf);
1592 /* If someone requested we add a label at the end of the transformed
1594 if (this_tf.fallthru_label)
1596 /* This must be reached only if ndests == 0. */
1597 gimple x = gimple_build_label (this_tf.fallthru_label);
1598 gimple_seq_add_stmt (&this_tf.top_p_seq, x);
1601 VEC_free (tree, heap, this_tf.dest_array);
1602 if (this_tf.goto_queue)
1603 free (this_tf.goto_queue);
1604 if (this_tf.goto_queue_map)
1605 pointer_map_destroy (this_tf.goto_queue_map);
1607 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1608 If there was no old eh_seq, then the append is trivially already done. */
1612 eh_seq = old_eh_seq;
1615 gimple_seq new_eh_seq = eh_seq;
1616 eh_seq = old_eh_seq;
1617 gimple_seq_add_seq(&eh_seq, new_eh_seq);
1621 return this_tf.top_p_seq;
1624 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1625 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1626 exception region trees that records all the magic. */
1629 lower_catch (struct leh_state *state, gimple tp)
1631 eh_region try_region = NULL;
1632 struct leh_state this_state = *state;
1633 gimple_stmt_iterator gsi;
1637 location_t try_catch_loc = gimple_location (tp);
1639 if (flag_exceptions)
1641 try_region = gen_eh_region_try (state->cur_region);
1642 this_state.cur_region = try_region;
1645 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
1647 if (!eh_region_may_contain_throw (try_region))
1648 return gimple_try_eval (tp);
1651 emit_eh_dispatch (&new_seq, try_region);
1652 emit_resx (&new_seq, try_region);
1654 this_state.cur_region = state->cur_region;
1655 this_state.ehp_region = try_region;
1658 for (gsi = gsi_start (gimple_try_cleanup (tp));
1666 gcatch = gsi_stmt (gsi);
1667 c = gen_eh_region_catch (try_region, gimple_catch_types (gcatch));
1669 handler = gimple_catch_handler (gcatch);
1670 lower_eh_constructs_1 (&this_state, handler);
1672 c->label = create_artificial_label (UNKNOWN_LOCATION);
1673 x = gimple_build_label (c->label);
1674 gimple_seq_add_stmt (&new_seq, x);
1676 gimple_seq_add_seq (&new_seq, handler);
1678 if (gimple_seq_may_fallthru (new_seq))
1681 out_label = create_artificial_label (try_catch_loc);
1683 x = gimple_build_goto (out_label);
1684 gimple_seq_add_stmt (&new_seq, x);
1690 gimple_try_set_cleanup (tp, new_seq);
1692 return frob_into_branch_around (tp, try_region, out_label);
1695 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1696 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1697 region trees that record all the magic. */
1700 lower_eh_filter (struct leh_state *state, gimple tp)
1702 struct leh_state this_state = *state;
1703 eh_region this_region = NULL;
1707 inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
1709 if (flag_exceptions)
1711 this_region = gen_eh_region_allowed (state->cur_region,
1712 gimple_eh_filter_types (inner));
1713 this_state.cur_region = this_region;
1716 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
1718 if (!eh_region_may_contain_throw (this_region))
1719 return gimple_try_eval (tp);
1722 this_state.cur_region = state->cur_region;
1723 this_state.ehp_region = this_region;
1725 emit_eh_dispatch (&new_seq, this_region);
1726 emit_resx (&new_seq, this_region);
1728 this_region->u.allowed.label = create_artificial_label (UNKNOWN_LOCATION);
1729 x = gimple_build_label (this_region->u.allowed.label);
1730 gimple_seq_add_stmt (&new_seq, x);
1732 lower_eh_constructs_1 (&this_state, gimple_eh_filter_failure (inner));
1733 gimple_seq_add_seq (&new_seq, gimple_eh_filter_failure (inner));
1735 gimple_try_set_cleanup (tp, new_seq);
1737 return frob_into_branch_around (tp, this_region, NULL);
1740 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1741 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1742 plus the exception region trees that record all the magic. */
1745 lower_eh_must_not_throw (struct leh_state *state, gimple tp)
1747 struct leh_state this_state = *state;
1749 if (flag_exceptions)
1751 gimple inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
1752 eh_region this_region;
1754 this_region = gen_eh_region_must_not_throw (state->cur_region);
1755 this_region->u.must_not_throw.failure_decl
1756 = gimple_eh_must_not_throw_fndecl (inner);
1757 this_region->u.must_not_throw.failure_loc = gimple_location (tp);
1759 /* In order to get mangling applied to this decl, we must mark it
1760 used now. Otherwise, pass_ipa_free_lang_data won't think it
1762 TREE_USED (this_region->u.must_not_throw.failure_decl) = 1;
1764 this_state.cur_region = this_region;
1767 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
1769 return gimple_try_eval (tp);
1772 /* Implement a cleanup expression. This is similar to try-finally,
1773 except that we only execute the cleanup block for exception edges. */
1776 lower_cleanup (struct leh_state *state, gimple tp)
1778 struct leh_state this_state = *state;
1779 eh_region this_region = NULL;
1780 struct leh_tf_state fake_tf;
1783 if (flag_exceptions)
1785 this_region = gen_eh_region_cleanup (state->cur_region);
1786 this_state.cur_region = this_region;
1789 lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
1791 if (!eh_region_may_contain_throw (this_region))
1792 return gimple_try_eval (tp);
1794 /* Build enough of a try-finally state so that we can reuse
1795 honor_protect_cleanup_actions. */
1796 memset (&fake_tf, 0, sizeof (fake_tf));
1797 fake_tf.top_p = fake_tf.try_finally_expr = tp;
1798 fake_tf.outer = state;
1799 fake_tf.region = this_region;
1800 fake_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
1801 fake_tf.may_throw = true;
1803 honor_protect_cleanup_actions (state, NULL, &fake_tf);
1805 if (fake_tf.may_throw)
1807 /* In this case honor_protect_cleanup_actions had nothing to do,
1808 and we should process this normally. */
1809 lower_eh_constructs_1 (state, gimple_try_cleanup (tp));
1810 result = frob_into_branch_around (tp, this_region,
1811 fake_tf.fallthru_label);
1815 /* In this case honor_protect_cleanup_actions did nearly all of
1816 the work. All we have left is to append the fallthru_label. */
1818 result = gimple_try_eval (tp);
1819 if (fake_tf.fallthru_label)
1821 gimple x = gimple_build_label (fake_tf.fallthru_label);
1822 gimple_seq_add_stmt (&result, x);
1828 /* Main loop for lowering eh constructs. Also moves gsi to the next
1832 lower_eh_constructs_2 (struct leh_state *state, gimple_stmt_iterator *gsi)
1836 gimple stmt = gsi_stmt (*gsi);
1838 switch (gimple_code (stmt))
1842 tree fndecl = gimple_call_fndecl (stmt);
1845 if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
1846 switch (DECL_FUNCTION_CODE (fndecl))
1848 case BUILT_IN_EH_POINTER:
1849 /* The front end may have generated a call to
1850 __builtin_eh_pointer (0) within a catch region. Replace
1851 this zero argument with the current catch region number. */
1852 if (state->ehp_region)
1854 tree nr = build_int_cst (NULL, state->ehp_region->index);
1855 gimple_call_set_arg (stmt, 0, nr);
1859 /* The user has dome something silly. Remove it. */
1860 rhs = build_int_cst (ptr_type_node, 0);
1865 case BUILT_IN_EH_FILTER:
1866 /* ??? This should never appear, but since it's a builtin it
1867 is accessible to abuse by users. Just remove it and
1868 replace the use with the arbitrary value zero. */
1869 rhs = build_int_cst (TREE_TYPE (TREE_TYPE (fndecl)), 0);
1871 lhs = gimple_call_lhs (stmt);
1872 x = gimple_build_assign (lhs, rhs);
1873 gsi_insert_before (gsi, x, GSI_SAME_STMT);
1876 case BUILT_IN_EH_COPY_VALUES:
1877 /* Likewise this should not appear. Remove it. */
1878 gsi_remove (gsi, true);
1888 /* If the stmt can throw use a new temporary for the assignment
1889 to a LHS. This makes sure the old value of the LHS is
1890 available on the EH edge. Only do so for statements that
1891 potentially fall thru (no noreturn calls e.g.), otherwise
1892 this new assignment might create fake fallthru regions. */
1893 if (stmt_could_throw_p (stmt)
1894 && gimple_has_lhs (stmt)
1895 && gimple_stmt_may_fallthru (stmt)
1896 && !tree_could_throw_p (gimple_get_lhs (stmt))
1897 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt))))
1899 tree lhs = gimple_get_lhs (stmt);
1900 tree tmp = create_tmp_var (TREE_TYPE (lhs), NULL);
1901 gimple s = gimple_build_assign (lhs, tmp);
1902 gimple_set_location (s, gimple_location (stmt));
1903 gimple_set_block (s, gimple_block (stmt));
1904 gimple_set_lhs (stmt, tmp);
1905 if (TREE_CODE (TREE_TYPE (tmp)) == COMPLEX_TYPE
1906 || TREE_CODE (TREE_TYPE (tmp)) == VECTOR_TYPE)
1907 DECL_GIMPLE_REG_P (tmp) = 1;
1908 gsi_insert_after (gsi, s, GSI_SAME_STMT);
1910 /* Look for things that can throw exceptions, and record them. */
1911 if (state->cur_region && stmt_could_throw_p (stmt))
1913 record_stmt_eh_region (state->cur_region, stmt);
1914 note_eh_region_may_contain_throw (state->cur_region);
1921 maybe_record_in_goto_queue (state, stmt);
1925 verify_norecord_switch_expr (state, stmt);
1929 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
1930 replace = lower_try_finally (state, stmt);
1933 x = gimple_seq_first_stmt (gimple_try_cleanup (stmt));
1936 replace = gimple_try_eval (stmt);
1937 lower_eh_constructs_1 (state, replace);
1940 switch (gimple_code (x))
1943 replace = lower_catch (state, stmt);
1945 case GIMPLE_EH_FILTER:
1946 replace = lower_eh_filter (state, stmt);
1948 case GIMPLE_EH_MUST_NOT_THROW:
1949 replace = lower_eh_must_not_throw (state, stmt);
1952 replace = lower_cleanup (state, stmt);
1957 /* Remove the old stmt and insert the transformed sequence
1959 gsi_insert_seq_before (gsi, replace, GSI_SAME_STMT);
1960 gsi_remove (gsi, true);
1962 /* Return since we don't want gsi_next () */
1966 /* A type, a decl, or some kind of statement that we're not
1967 interested in. Don't walk them. */
1974 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
1977 lower_eh_constructs_1 (struct leh_state *state, gimple_seq seq)
1979 gimple_stmt_iterator gsi;
1980 for (gsi = gsi_start (seq); !gsi_end_p (gsi);)
1981 lower_eh_constructs_2 (state, &gsi);
1985 lower_eh_constructs (void)
1987 struct leh_state null_state;
1990 bodyp = gimple_body (current_function_decl);
1994 finally_tree = htab_create (31, struct_ptr_hash, struct_ptr_eq, free);
1995 eh_region_may_contain_throw_map = BITMAP_ALLOC (NULL);
1996 memset (&null_state, 0, sizeof (null_state));
1998 collect_finally_tree_1 (bodyp, NULL);
1999 lower_eh_constructs_1 (&null_state, bodyp);
2001 /* We assume there's a return statement, or something, at the end of
2002 the function, and thus ploping the EH sequence afterward won't
2004 gcc_assert (!gimple_seq_may_fallthru (bodyp));
2005 gimple_seq_add_seq (&bodyp, eh_seq);
2007 /* We assume that since BODYP already existed, adding EH_SEQ to it
2008 didn't change its value, and we don't have to re-set the function. */
2009 gcc_assert (bodyp == gimple_body (current_function_decl));
2011 htab_delete (finally_tree);
2012 BITMAP_FREE (eh_region_may_contain_throw_map);
2015 /* If this function needs a language specific EH personality routine
2016 and the frontend didn't already set one do so now. */
2017 if (function_needs_eh_personality (cfun) == eh_personality_lang
2018 && !DECL_FUNCTION_PERSONALITY (current_function_decl))
2019 DECL_FUNCTION_PERSONALITY (current_function_decl)
2020 = lang_hooks.eh_personality ();
2025 struct gimple_opt_pass pass_lower_eh =
2031 lower_eh_constructs, /* execute */
2034 0, /* static_pass_number */
2035 TV_TREE_EH, /* tv_id */
2036 PROP_gimple_lcf, /* properties_required */
2037 PROP_gimple_leh, /* properties_provided */
2038 0, /* properties_destroyed */
2039 0, /* todo_flags_start */
2040 TODO_dump_func /* todo_flags_finish */
2044 /* Create the multiple edges from an EH_DISPATCH statement to all of
2045 the possible handlers for its EH region. Return true if there's
2046 no fallthru edge; false if there is. */
2049 make_eh_dispatch_edges (gimple stmt)
2053 basic_block src, dst;
2055 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
2056 src = gimple_bb (stmt);
2061 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
2063 dst = label_to_block (c->label);
2064 make_edge (src, dst, 0);
2066 /* A catch-all handler doesn't have a fallthru. */
2067 if (c->type_list == NULL)
2072 case ERT_ALLOWED_EXCEPTIONS:
2073 dst = label_to_block (r->u.allowed.label);
2074 make_edge (src, dst, 0);
2084 /* Create the single EH edge from STMT to its nearest landing pad,
2085 if there is such a landing pad within the current function. */
2088 make_eh_edges (gimple stmt)
2090 basic_block src, dst;
2094 lp_nr = lookup_stmt_eh_lp (stmt);
2098 lp = get_eh_landing_pad_from_number (lp_nr);
2099 gcc_assert (lp != NULL);
2101 src = gimple_bb (stmt);
2102 dst = label_to_block (lp->post_landing_pad);
2103 make_edge (src, dst, EDGE_EH);
2106 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2107 do not actually perform the final edge redirection.
2109 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2110 we intend to change the destination EH region as well; this means
2111 EH_LANDING_PAD_NR must already be set on the destination block label.
2112 If false, we're being called from generic cfg manipulation code and we
2113 should preserve our place within the region tree. */
2116 redirect_eh_edge_1 (edge edge_in, basic_block new_bb, bool change_region)
2118 eh_landing_pad old_lp, new_lp;
2121 int old_lp_nr, new_lp_nr;
2122 tree old_label, new_label;
2126 old_bb = edge_in->dest;
2127 old_label = gimple_block_label (old_bb);
2128 old_lp_nr = EH_LANDING_PAD_NR (old_label);
2129 gcc_assert (old_lp_nr > 0);
2130 old_lp = get_eh_landing_pad_from_number (old_lp_nr);
2132 throw_stmt = last_stmt (edge_in->src);
2133 gcc_assert (lookup_stmt_eh_lp (throw_stmt) == old_lp_nr);
2135 new_label = gimple_block_label (new_bb);
2137 /* Look for an existing region that might be using NEW_BB already. */
2138 new_lp_nr = EH_LANDING_PAD_NR (new_label);
2141 new_lp = get_eh_landing_pad_from_number (new_lp_nr);
2142 gcc_assert (new_lp);
2144 /* Unless CHANGE_REGION is true, the new and old landing pad
2145 had better be associated with the same EH region. */
2146 gcc_assert (change_region || new_lp->region == old_lp->region);
2151 gcc_assert (!change_region);
2154 /* Notice when we redirect the last EH edge away from OLD_BB. */
2155 FOR_EACH_EDGE (e, ei, old_bb->preds)
2156 if (e != edge_in && (e->flags & EDGE_EH))
2161 /* NEW_LP already exists. If there are still edges into OLD_LP,
2162 there's nothing to do with the EH tree. If there are no more
2163 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2164 If CHANGE_REGION is true, then our caller is expecting to remove
2166 if (e == NULL && !change_region)
2167 remove_eh_landing_pad (old_lp);
2171 /* No correct landing pad exists. If there are no more edges
2172 into OLD_LP, then we can simply re-use the existing landing pad.
2173 Otherwise, we have to create a new landing pad. */
2176 EH_LANDING_PAD_NR (old_lp->post_landing_pad) = 0;
2180 new_lp = gen_eh_landing_pad (old_lp->region);
2181 new_lp->post_landing_pad = new_label;
2182 EH_LANDING_PAD_NR (new_label) = new_lp->index;
2185 /* Maybe move the throwing statement to the new region. */
2186 if (old_lp != new_lp)
2188 remove_stmt_from_eh_lp (throw_stmt);
2189 add_stmt_to_eh_lp (throw_stmt, new_lp->index);
2193 /* Redirect EH edge E to NEW_BB. */
2196 redirect_eh_edge (edge edge_in, basic_block new_bb)
2198 redirect_eh_edge_1 (edge_in, new_bb, false);
2199 return ssa_redirect_edge (edge_in, new_bb);
2202 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2203 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2204 The actual edge update will happen in the caller. */
2207 redirect_eh_dispatch_edge (gimple stmt, edge e, basic_block new_bb)
2209 tree new_lab = gimple_block_label (new_bb);
2210 bool any_changed = false;
2215 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
2219 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
2221 old_bb = label_to_block (c->label);
2222 if (old_bb == e->dest)
2230 case ERT_ALLOWED_EXCEPTIONS:
2231 old_bb = label_to_block (r->u.allowed.label);
2232 gcc_assert (old_bb == e->dest);
2233 r->u.allowed.label = new_lab;
2241 gcc_assert (any_changed);
2244 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2247 operation_could_trap_helper_p (enum tree_code op,
2258 case TRUNC_DIV_EXPR:
2260 case FLOOR_DIV_EXPR:
2261 case ROUND_DIV_EXPR:
2262 case EXACT_DIV_EXPR:
2264 case FLOOR_MOD_EXPR:
2265 case ROUND_MOD_EXPR:
2266 case TRUNC_MOD_EXPR:
2268 if (honor_snans || honor_trapv)
2271 return flag_trapping_math;
2272 if (!TREE_CONSTANT (divisor) || integer_zerop (divisor))
2281 /* Some floating point comparisons may trap. */
2286 case UNORDERED_EXPR:
2296 case FIX_TRUNC_EXPR:
2297 /* Conversion of floating point might trap. */
2303 /* These operations don't trap with floating point. */
2311 /* Any floating arithmetic may trap. */
2312 if (fp_operation && flag_trapping_math)
2319 /* Any floating arithmetic may trap. */
2320 if (fp_operation && flag_trapping_math)
2328 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2329 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2330 type operands that may trap. If OP is a division operator, DIVISOR contains
2331 the value of the divisor. */
2334 operation_could_trap_p (enum tree_code op, bool fp_operation, bool honor_trapv,
2337 bool honor_nans = (fp_operation && flag_trapping_math
2338 && !flag_finite_math_only);
2339 bool honor_snans = fp_operation && flag_signaling_nans != 0;
2342 if (TREE_CODE_CLASS (op) != tcc_comparison
2343 && TREE_CODE_CLASS (op) != tcc_unary
2344 && TREE_CODE_CLASS (op) != tcc_binary)
2347 return operation_could_trap_helper_p (op, fp_operation, honor_trapv,
2348 honor_nans, honor_snans, divisor,
2352 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2353 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2354 This routine expects only GIMPLE lhs or rhs input. */
2357 tree_could_trap_p (tree expr)
2359 enum tree_code code;
2360 bool fp_operation = false;
2361 bool honor_trapv = false;
2362 tree t, base, div = NULL_TREE;
2367 code = TREE_CODE (expr);
2368 t = TREE_TYPE (expr);
2372 if (COMPARISON_CLASS_P (expr))
2373 fp_operation = FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0)));
2375 fp_operation = FLOAT_TYPE_P (t);
2376 honor_trapv = INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t);
2379 if (TREE_CODE_CLASS (code) == tcc_binary)
2380 div = TREE_OPERAND (expr, 1);
2381 if (operation_could_trap_p (code, fp_operation, honor_trapv, div))
2387 case TARGET_MEM_REF:
2388 /* For TARGET_MEM_REFs use the information based on the original
2390 expr = TMR_ORIGINAL (expr);
2391 code = TREE_CODE (expr);
2398 case VIEW_CONVERT_EXPR:
2399 case WITH_SIZE_EXPR:
2400 expr = TREE_OPERAND (expr, 0);
2401 code = TREE_CODE (expr);
2404 case ARRAY_RANGE_REF:
2405 base = TREE_OPERAND (expr, 0);
2406 if (tree_could_trap_p (base))
2408 if (TREE_THIS_NOTRAP (expr))
2410 return !range_in_array_bounds_p (expr);
2413 base = TREE_OPERAND (expr, 0);
2414 if (tree_could_trap_p (base))
2416 if (TREE_THIS_NOTRAP (expr))
2418 return !in_array_bounds_p (expr);
2421 case ALIGN_INDIRECT_REF:
2422 case MISALIGNED_INDIRECT_REF:
2423 return !TREE_THIS_NOTRAP (expr);
2426 return TREE_THIS_VOLATILE (expr);
2429 t = get_callee_fndecl (expr);
2430 /* Assume that calls to weak functions may trap. */
2431 if (!t || !DECL_P (t) || DECL_WEAK (t))
2441 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2442 an assignment or a conditional) may throw. */
2445 stmt_could_throw_1_p (gimple stmt)
2447 enum tree_code code = gimple_expr_code (stmt);
2448 bool honor_nans = false;
2449 bool honor_snans = false;
2450 bool fp_operation = false;
2451 bool honor_trapv = false;
2456 if (TREE_CODE_CLASS (code) == tcc_comparison
2457 || TREE_CODE_CLASS (code) == tcc_unary
2458 || TREE_CODE_CLASS (code) == tcc_binary)
2460 t = gimple_expr_type (stmt);
2461 fp_operation = FLOAT_TYPE_P (t);
2464 honor_nans = flag_trapping_math && !flag_finite_math_only;
2465 honor_snans = flag_signaling_nans != 0;
2467 else if (INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t))
2471 /* Check if the main expression may trap. */
2472 t = is_gimple_assign (stmt) ? gimple_assign_rhs2 (stmt) : NULL;
2473 ret = operation_could_trap_helper_p (code, fp_operation, honor_trapv,
2474 honor_nans, honor_snans, t,
2479 /* If the expression does not trap, see if any of the individual operands may
2481 for (i = 0; i < gimple_num_ops (stmt); i++)
2482 if (tree_could_trap_p (gimple_op (stmt, i)))
2489 /* Return true if statement STMT could throw an exception. */
2492 stmt_could_throw_p (gimple stmt)
2494 if (!flag_exceptions)
2497 /* The only statements that can throw an exception are assignments,
2498 conditionals, calls, resx, and asms. */
2499 switch (gimple_code (stmt))
2505 return !gimple_call_nothrow_p (stmt);
2509 if (!flag_non_call_exceptions)
2511 return stmt_could_throw_1_p (stmt);
2514 if (!flag_non_call_exceptions)
2516 return gimple_asm_volatile_p (stmt);
2524 /* Return true if expression T could throw an exception. */
2527 tree_could_throw_p (tree t)
2529 if (!flag_exceptions)
2531 if (TREE_CODE (t) == MODIFY_EXPR)
2533 if (flag_non_call_exceptions
2534 && tree_could_trap_p (TREE_OPERAND (t, 0)))
2536 t = TREE_OPERAND (t, 1);
2539 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2540 t = TREE_OPERAND (t, 0);
2541 if (TREE_CODE (t) == CALL_EXPR)
2542 return (call_expr_flags (t) & ECF_NOTHROW) == 0;
2543 if (flag_non_call_exceptions)
2544 return tree_could_trap_p (t);
2548 /* Return true if STMT can throw an exception that is not caught within
2549 the current function (CFUN). */
2552 stmt_can_throw_external (gimple stmt)
2556 if (!stmt_could_throw_p (stmt))
2559 lp_nr = lookup_stmt_eh_lp (stmt);
2563 /* Return true if STMT can throw an exception that is caught within
2564 the current function (CFUN). */
2567 stmt_can_throw_internal (gimple stmt)
2571 if (!stmt_could_throw_p (stmt))
2574 lp_nr = lookup_stmt_eh_lp (stmt);
2578 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2579 remove any entry it might have from the EH table. Return true if
2580 any change was made. */
2583 maybe_clean_eh_stmt_fn (struct function *ifun, gimple stmt)
2585 if (stmt_could_throw_p (stmt))
2587 return remove_stmt_from_eh_lp_fn (ifun, stmt);
2590 /* Likewise, but always use the current function. */
2593 maybe_clean_eh_stmt (gimple stmt)
2595 return maybe_clean_eh_stmt_fn (cfun, stmt);
2598 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2599 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2600 in the table if it should be in there. Return TRUE if a replacement was
2601 done that my require an EH edge purge. */
2604 maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt)
2606 int lp_nr = lookup_stmt_eh_lp (old_stmt);
2610 bool new_stmt_could_throw = stmt_could_throw_p (new_stmt);
2612 if (new_stmt == old_stmt && new_stmt_could_throw)
2615 remove_stmt_from_eh_lp (old_stmt);
2616 if (new_stmt_could_throw)
2618 add_stmt_to_eh_lp (new_stmt, lp_nr);
2628 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statment NEW_STMT
2629 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2630 operand is the return value of duplicate_eh_regions. */
2633 maybe_duplicate_eh_stmt_fn (struct function *new_fun, gimple new_stmt,
2634 struct function *old_fun, gimple old_stmt,
2635 struct pointer_map_t *map, int default_lp_nr)
2637 int old_lp_nr, new_lp_nr;
2640 if (!stmt_could_throw_p (new_stmt))
2643 old_lp_nr = lookup_stmt_eh_lp_fn (old_fun, old_stmt);
2646 if (default_lp_nr == 0)
2648 new_lp_nr = default_lp_nr;
2650 else if (old_lp_nr > 0)
2652 eh_landing_pad old_lp, new_lp;
2654 old_lp = VEC_index (eh_landing_pad, old_fun->eh->lp_array, old_lp_nr);
2655 slot = pointer_map_contains (map, old_lp);
2656 new_lp = (eh_landing_pad) *slot;
2657 new_lp_nr = new_lp->index;
2661 eh_region old_r, new_r;
2663 old_r = VEC_index (eh_region, old_fun->eh->region_array, -old_lp_nr);
2664 slot = pointer_map_contains (map, old_r);
2665 new_r = (eh_region) *slot;
2666 new_lp_nr = -new_r->index;
2669 add_stmt_to_eh_lp_fn (new_fun, new_stmt, new_lp_nr);
2673 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2674 and thus no remapping is required. */
2677 maybe_duplicate_eh_stmt (gimple new_stmt, gimple old_stmt)
2681 if (!stmt_could_throw_p (new_stmt))
2684 lp_nr = lookup_stmt_eh_lp (old_stmt);
2688 add_stmt_to_eh_lp (new_stmt, lp_nr);
2692 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2693 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2694 this only handles handlers consisting of a single call, as that's the
2695 important case for C++: a destructor call for a particular object showing
2696 up in multiple handlers. */
2699 same_handler_p (gimple_seq oneh, gimple_seq twoh)
2701 gimple_stmt_iterator gsi;
2705 gsi = gsi_start (oneh);
2706 if (!gsi_one_before_end_p (gsi))
2708 ones = gsi_stmt (gsi);
2710 gsi = gsi_start (twoh);
2711 if (!gsi_one_before_end_p (gsi))
2713 twos = gsi_stmt (gsi);
2715 if (!is_gimple_call (ones)
2716 || !is_gimple_call (twos)
2717 || gimple_call_lhs (ones)
2718 || gimple_call_lhs (twos)
2719 || gimple_call_chain (ones)
2720 || gimple_call_chain (twos)
2721 || !operand_equal_p (gimple_call_fn (ones), gimple_call_fn (twos), 0)
2722 || gimple_call_num_args (ones) != gimple_call_num_args (twos))
2725 for (ai = 0; ai < gimple_call_num_args (ones); ++ai)
2726 if (!operand_equal_p (gimple_call_arg (ones, ai),
2727 gimple_call_arg (twos, ai), 0))
2734 try { A() } finally { try { ~B() } catch { ~A() } }
2735 try { ... } finally { ~A() }
2737 try { A() } catch { ~B() }
2738 try { ~B() ... } finally { ~A() }
2740 This occurs frequently in C++, where A is a local variable and B is a
2741 temporary used in the initializer for A. */
2744 optimize_double_finally (gimple one, gimple two)
2747 gimple_stmt_iterator gsi;
2749 gsi = gsi_start (gimple_try_cleanup (one));
2750 if (!gsi_one_before_end_p (gsi))
2753 oneh = gsi_stmt (gsi);
2754 if (gimple_code (oneh) != GIMPLE_TRY
2755 || gimple_try_kind (oneh) != GIMPLE_TRY_CATCH)
2758 if (same_handler_p (gimple_try_cleanup (oneh), gimple_try_cleanup (two)))
2760 gimple_seq seq = gimple_try_eval (oneh);
2762 gimple_try_set_cleanup (one, seq);
2763 gimple_try_set_kind (one, GIMPLE_TRY_CATCH);
2764 seq = copy_gimple_seq_and_replace_locals (seq);
2765 gimple_seq_add_seq (&seq, gimple_try_eval (two));
2766 gimple_try_set_eval (two, seq);
2770 /* Perform EH refactoring optimizations that are simpler to do when code
2771 flow has been lowered but EH structures haven't. */
2774 refactor_eh_r (gimple_seq seq)
2776 gimple_stmt_iterator gsi;
2781 gsi = gsi_start (seq);
2785 if (gsi_end_p (gsi))
2788 two = gsi_stmt (gsi);
2791 && gimple_code (one) == GIMPLE_TRY
2792 && gimple_code (two) == GIMPLE_TRY
2793 && gimple_try_kind (one) == GIMPLE_TRY_FINALLY
2794 && gimple_try_kind (two) == GIMPLE_TRY_FINALLY)
2795 optimize_double_finally (one, two);
2797 switch (gimple_code (one))
2800 refactor_eh_r (gimple_try_eval (one));
2801 refactor_eh_r (gimple_try_cleanup (one));
2804 refactor_eh_r (gimple_catch_handler (one));
2806 case GIMPLE_EH_FILTER:
2807 refactor_eh_r (gimple_eh_filter_failure (one));
2822 refactor_eh_r (gimple_body (current_function_decl));
2827 gate_refactor_eh (void)
2829 return flag_exceptions != 0;
2832 struct gimple_opt_pass pass_refactor_eh =
2837 gate_refactor_eh, /* gate */
2838 refactor_eh, /* execute */
2841 0, /* static_pass_number */
2842 TV_TREE_EH, /* tv_id */
2843 PROP_gimple_lcf, /* properties_required */
2844 0, /* properties_provided */
2845 0, /* properties_destroyed */
2846 0, /* todo_flags_start */
2847 TODO_dump_func /* todo_flags_finish */
2851 /* At the end of gimple optimization, we can lower RESX. */
2854 lower_resx (basic_block bb, gimple stmt, struct pointer_map_t *mnt_map)
2857 eh_region src_r, dst_r;
2858 gimple_stmt_iterator gsi;
2863 lp_nr = lookup_stmt_eh_lp (stmt);
2865 dst_r = get_eh_region_from_lp_number (lp_nr);
2869 src_r = get_eh_region_from_number (gimple_resx_region (stmt));
2870 gsi = gsi_last_bb (bb);
2874 /* We can wind up with no source region when pass_cleanup_eh shows
2875 that there are no entries into an eh region and deletes it, but
2876 then the block that contains the resx isn't removed. This can
2877 happen without optimization when the switch statement created by
2878 lower_try_finally_switch isn't simplified to remove the eh case.
2880 Resolve this by expanding the resx node to an abort. */
2882 fn = implicit_built_in_decls[BUILT_IN_TRAP];
2883 x = gimple_build_call (fn, 0);
2884 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
2886 while (EDGE_COUNT (bb->succs) > 0)
2887 remove_edge (EDGE_SUCC (bb, 0));
2891 /* When we have a destination region, we resolve this by copying
2892 the excptr and filter values into place, and changing the edge
2893 to immediately after the landing pad. */
2902 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
2903 the failure decl into a new block, if needed. */
2904 gcc_assert (dst_r->type == ERT_MUST_NOT_THROW);
2906 slot = pointer_map_contains (mnt_map, dst_r);
2909 gimple_stmt_iterator gsi2;
2911 new_bb = create_empty_bb (bb);
2912 lab = gimple_block_label (new_bb);
2913 gsi2 = gsi_start_bb (new_bb);
2915 fn = dst_r->u.must_not_throw.failure_decl;
2916 x = gimple_build_call (fn, 0);
2917 gimple_set_location (x, dst_r->u.must_not_throw.failure_loc);
2918 gsi_insert_after (&gsi2, x, GSI_CONTINUE_LINKING);
2920 slot = pointer_map_insert (mnt_map, dst_r);
2926 new_bb = label_to_block (lab);
2929 gcc_assert (EDGE_COUNT (bb->succs) == 0);
2930 e = make_edge (bb, new_bb, EDGE_FALLTHRU);
2931 e->count = bb->count;
2932 e->probability = REG_BR_PROB_BASE;
2937 tree dst_nr = build_int_cst (NULL, dst_r->index);
2939 fn = implicit_built_in_decls[BUILT_IN_EH_COPY_VALUES];
2940 src_nr = build_int_cst (NULL, src_r->index);
2941 x = gimple_build_call (fn, 2, dst_nr, src_nr);
2942 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
2944 /* Update the flags for the outgoing edge. */
2945 e = single_succ_edge (bb);
2946 gcc_assert (e->flags & EDGE_EH);
2947 e->flags = (e->flags & ~EDGE_EH) | EDGE_FALLTHRU;
2949 /* If there are no more EH users of the landing pad, delete it. */
2950 FOR_EACH_EDGE (e, ei, e->dest->preds)
2951 if (e->flags & EDGE_EH)
2955 eh_landing_pad lp = get_eh_landing_pad_from_number (lp_nr);
2956 remove_eh_landing_pad (lp);
2966 /* When we don't have a destination region, this exception escapes
2967 up the call chain. We resolve this by generating a call to the
2968 _Unwind_Resume library function. */
2970 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
2971 with no arguments for C++ and Java. Check for that. */
2972 if (src_r->use_cxa_end_cleanup)
2974 fn = implicit_built_in_decls[BUILT_IN_CXA_END_CLEANUP];
2975 x = gimple_build_call (fn, 0);
2976 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
2980 fn = implicit_built_in_decls[BUILT_IN_EH_POINTER];
2981 src_nr = build_int_cst (NULL, src_r->index);
2982 x = gimple_build_call (fn, 1, src_nr);
2983 var = create_tmp_var (ptr_type_node, NULL);
2984 var = make_ssa_name (var, x);
2985 gimple_call_set_lhs (x, var);
2986 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
2988 fn = implicit_built_in_decls[BUILT_IN_UNWIND_RESUME];
2989 x = gimple_build_call (fn, 1, var);
2990 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
2993 gcc_assert (EDGE_COUNT (bb->succs) == 0);
2996 gsi_remove (&gsi, true);
3002 execute_lower_resx (void)
3005 struct pointer_map_t *mnt_map;
3006 bool dominance_invalidated = false;
3007 bool any_rewritten = false;
3009 mnt_map = pointer_map_create ();
3013 gimple last = last_stmt (bb);
3014 if (last && is_gimple_resx (last))
3016 dominance_invalidated |= lower_resx (bb, last, mnt_map);
3017 any_rewritten = true;
3021 pointer_map_destroy (mnt_map);
3023 if (dominance_invalidated)
3025 free_dominance_info (CDI_DOMINATORS);
3026 free_dominance_info (CDI_POST_DOMINATORS);
3029 return any_rewritten ? TODO_update_ssa_only_virtuals : 0;
3033 gate_lower_resx (void)
3035 return flag_exceptions != 0;
3038 struct gimple_opt_pass pass_lower_resx =
3043 gate_lower_resx, /* gate */
3044 execute_lower_resx, /* execute */
3047 0, /* static_pass_number */
3048 TV_TREE_EH, /* tv_id */
3049 PROP_gimple_lcf, /* properties_required */
3050 0, /* properties_provided */
3051 0, /* properties_destroyed */
3052 0, /* todo_flags_start */
3053 TODO_dump_func | TODO_verify_flow /* todo_flags_finish */
3058 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3059 we have found some duplicate labels and removed some edges. */
3062 lower_eh_dispatch (basic_block src, gimple stmt)
3064 gimple_stmt_iterator gsi;
3069 bool redirected = false;
3071 region_nr = gimple_eh_dispatch_region (stmt);
3072 r = get_eh_region_from_number (region_nr);
3074 gsi = gsi_last_bb (src);
3080 VEC (tree, heap) *labels = NULL;
3081 tree default_label = NULL;
3085 struct pointer_set_t *seen_values = pointer_set_create ();
3087 /* Collect the labels for a switch. Zero the post_landing_pad
3088 field becase we'll no longer have anything keeping these labels
3089 in existance and the optimizer will be free to merge these
3091 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
3093 tree tp_node, flt_node, lab = c->label;
3094 bool have_label = false;
3097 tp_node = c->type_list;
3098 flt_node = c->filter_list;
3100 if (tp_node == NULL)
3102 default_label = lab;
3107 /* Filter out duplicate labels that arise when this handler
3108 is shadowed by an earlier one. When no labels are
3109 attached to the handler anymore, we remove
3110 the corresponding edge and then we delete unreachable
3111 blocks at the end of this pass. */
3112 if (! pointer_set_contains (seen_values, TREE_VALUE (flt_node)))
3114 tree t = build3 (CASE_LABEL_EXPR, void_type_node,
3115 TREE_VALUE (flt_node), NULL, lab);
3116 VEC_safe_push (tree, heap, labels, t);
3117 pointer_set_insert (seen_values, TREE_VALUE (flt_node));
3121 tp_node = TREE_CHAIN (tp_node);
3122 flt_node = TREE_CHAIN (flt_node);
3127 remove_edge (find_edge (src, label_to_block (lab)));
3132 /* Clean up the edge flags. */
3133 FOR_EACH_EDGE (e, ei, src->succs)
3135 if (e->flags & EDGE_FALLTHRU)
3137 /* If there was no catch-all, use the fallthru edge. */
3138 if (default_label == NULL)
3139 default_label = gimple_block_label (e->dest);
3140 e->flags &= ~EDGE_FALLTHRU;
3143 gcc_assert (default_label != NULL);
3145 /* Don't generate a switch if there's only a default case.
3146 This is common in the form of try { A; } catch (...) { B; }. */
3149 e = single_succ_edge (src);
3150 e->flags |= EDGE_FALLTHRU;
3154 fn = implicit_built_in_decls[BUILT_IN_EH_FILTER];
3155 x = gimple_build_call (fn, 1, build_int_cst (NULL, region_nr));
3156 filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
3157 filter = make_ssa_name (filter, x);
3158 gimple_call_set_lhs (x, filter);
3159 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3161 /* Turn the default label into a default case. */
3162 default_label = build3 (CASE_LABEL_EXPR, void_type_node,
3163 NULL, NULL, default_label);
3164 sort_case_labels (labels);
3166 x = gimple_build_switch_vec (filter, default_label, labels);
3167 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3169 VEC_free (tree, heap, labels);
3171 pointer_set_destroy (seen_values);
3175 case ERT_ALLOWED_EXCEPTIONS:
3177 edge b_e = BRANCH_EDGE (src);
3178 edge f_e = FALLTHRU_EDGE (src);
3180 fn = implicit_built_in_decls[BUILT_IN_EH_FILTER];
3181 x = gimple_build_call (fn, 1, build_int_cst (NULL, region_nr));
3182 filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
3183 filter = make_ssa_name (filter, x);
3184 gimple_call_set_lhs (x, filter);
3185 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3187 r->u.allowed.label = NULL;
3188 x = gimple_build_cond (EQ_EXPR, filter,
3189 build_int_cst (TREE_TYPE (filter),
3190 r->u.allowed.filter),
3191 NULL_TREE, NULL_TREE);
3192 gsi_insert_before (&gsi, x, GSI_SAME_STMT);
3194 b_e->flags = b_e->flags | EDGE_TRUE_VALUE;
3195 f_e->flags = (f_e->flags & ~EDGE_FALLTHRU) | EDGE_FALSE_VALUE;
3203 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3204 gsi_remove (&gsi, true);
3209 execute_lower_eh_dispatch (void)
3212 bool any_rewritten = false;
3213 bool redirected = false;
3215 assign_filter_values ();
3219 gimple last = last_stmt (bb);
3220 if (last && gimple_code (last) == GIMPLE_EH_DISPATCH)
3222 redirected |= lower_eh_dispatch (bb, last);
3223 any_rewritten = true;
3228 delete_unreachable_blocks ();
3229 return any_rewritten ? TODO_update_ssa_only_virtuals : 0;
3233 gate_lower_eh_dispatch (void)
3235 return cfun->eh->region_tree != NULL;
3238 struct gimple_opt_pass pass_lower_eh_dispatch =
3242 "ehdisp", /* name */
3243 gate_lower_eh_dispatch, /* gate */
3244 execute_lower_eh_dispatch, /* execute */
3247 0, /* static_pass_number */
3248 TV_TREE_EH, /* tv_id */
3249 PROP_gimple_lcf, /* properties_required */
3250 0, /* properties_provided */
3251 0, /* properties_destroyed */
3252 0, /* todo_flags_start */
3253 TODO_dump_func | TODO_verify_flow /* todo_flags_finish */
3257 /* Walk statements, see what regions are really referenced and remove
3258 those that are unused. */
3261 remove_unreachable_handlers (void)
3263 sbitmap r_reachable, lp_reachable;
3269 r_reachable = sbitmap_alloc (VEC_length (eh_region, cfun->eh->region_array));
3271 = sbitmap_alloc (VEC_length (eh_landing_pad, cfun->eh->lp_array));
3272 sbitmap_zero (r_reachable);
3273 sbitmap_zero (lp_reachable);
3277 gimple_stmt_iterator gsi = gsi_start_bb (bb);
3279 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
3281 gimple stmt = gsi_stmt (gsi);
3282 lp_nr = lookup_stmt_eh_lp (stmt);
3284 /* Negative LP numbers are MUST_NOT_THROW regions which
3285 are not considered BB enders. */
3287 SET_BIT (r_reachable, -lp_nr);
3289 /* Positive LP numbers are real landing pads, are are BB enders. */
3292 gcc_assert (gsi_one_before_end_p (gsi));
3293 region = get_eh_region_from_lp_number (lp_nr);
3294 SET_BIT (r_reachable, region->index);
3295 SET_BIT (lp_reachable, lp_nr);
3302 fprintf (dump_file, "Before removal of unreachable regions:\n");
3303 dump_eh_tree (dump_file, cfun);
3304 fprintf (dump_file, "Reachable regions: ");
3305 dump_sbitmap_file (dump_file, r_reachable);
3306 fprintf (dump_file, "Reachable landing pads: ");
3307 dump_sbitmap_file (dump_file, lp_reachable);
3311 VEC_iterate (eh_region, cfun->eh->region_array, r_nr, region); ++r_nr)
3312 if (region && !TEST_BIT (r_reachable, r_nr))
3315 fprintf (dump_file, "Removing unreachable region %d\n", r_nr);
3316 remove_eh_handler (region);
3320 VEC_iterate (eh_landing_pad, cfun->eh->lp_array, lp_nr, lp); ++lp_nr)
3321 if (lp && !TEST_BIT (lp_reachable, lp_nr))
3324 fprintf (dump_file, "Removing unreachable landing pad %d\n", lp_nr);
3325 remove_eh_landing_pad (lp);
3330 fprintf (dump_file, "\n\nAfter removal of unreachable regions:\n");
3331 dump_eh_tree (dump_file, cfun);
3332 fprintf (dump_file, "\n\n");
3335 sbitmap_free (r_reachable);
3336 sbitmap_free (lp_reachable);
3338 #ifdef ENABLE_CHECKING
3339 verify_eh_tree (cfun);
3343 /* Remove regions that do not have landing pads. This assumes
3344 that remove_unreachable_handlers has already been run, and
3345 that we've just manipulated the landing pads since then. */
3348 remove_unreachable_handlers_no_lp (void)
3353 for (i = 1; VEC_iterate (eh_region, cfun->eh->region_array, i, r); ++i)
3354 if (r && r->landing_pads == NULL && r->type != ERT_MUST_NOT_THROW)
3357 fprintf (dump_file, "Removing unreachable region %d\n", i);
3358 remove_eh_handler (r);
3362 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3363 optimisticaly split all sorts of edges, including EH edges. The
3364 optimization passes in between may not have needed them; if not,
3365 we should undo the split.
3367 Recognize this case by having one EH edge incoming to the BB and
3368 one normal edge outgoing; BB should be empty apart from the
3369 post_landing_pad label.
3371 Note that this is slightly different from the empty handler case
3372 handled by cleanup_empty_eh, in that the actual handler may yet
3373 have actual code but the landing pad has been separated from the
3374 handler. As such, cleanup_empty_eh relies on this transformation
3375 having been done first. */
3378 unsplit_eh (eh_landing_pad lp)
3380 basic_block bb = label_to_block (lp->post_landing_pad);
3381 gimple_stmt_iterator gsi;
3384 /* Quickly check the edge counts on BB for singularity. */
3385 if (EDGE_COUNT (bb->preds) != 1 || EDGE_COUNT (bb->succs) != 1)
3387 e_in = EDGE_PRED (bb, 0);
3388 e_out = EDGE_SUCC (bb, 0);
3390 /* Input edge must be EH and output edge must be normal. */
3391 if ((e_in->flags & EDGE_EH) == 0 || (e_out->flags & EDGE_EH) != 0)
3394 /* The block must be empty except for the labels and debug insns. */
3395 gsi = gsi_after_labels (bb);
3396 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
3397 gsi_next_nondebug (&gsi);
3398 if (!gsi_end_p (gsi))
3401 /* The destination block must not already have a landing pad
3402 for a different region. */
3403 for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
3405 gimple stmt = gsi_stmt (gsi);
3409 if (gimple_code (stmt) != GIMPLE_LABEL)
3411 lab = gimple_label_label (stmt);
3412 lp_nr = EH_LANDING_PAD_NR (lab);
3413 if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
3417 /* The new destination block must not already be a destination of
3418 the source block, lest we merge fallthru and eh edges and get
3419 all sorts of confused. */
3420 if (find_edge (e_in->src, e_out->dest))
3423 /* ??? We can get degenerate phis due to cfg cleanups. I would have
3424 thought this should have been cleaned up by a phicprop pass, but
3425 that doesn't appear to handle virtuals. Propagate by hand. */
3426 if (!gimple_seq_empty_p (phi_nodes (bb)))
3428 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
3430 gimple use_stmt, phi = gsi_stmt (gsi);
3431 tree lhs = gimple_phi_result (phi);
3432 tree rhs = gimple_phi_arg_def (phi, 0);
3433 use_operand_p use_p;
3434 imm_use_iterator iter;
3436 FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
3438 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
3439 SET_USE (use_p, rhs);
3442 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
3443 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
3445 remove_phi_node (&gsi, true);
3449 if (dump_file && (dump_flags & TDF_DETAILS))
3450 fprintf (dump_file, "Unsplit EH landing pad %d to block %i.\n",
3451 lp->index, e_out->dest->index);
3453 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
3454 a successor edge, humor it. But do the real CFG change with the
3455 predecessor of E_OUT in order to preserve the ordering of arguments
3456 to the PHI nodes in E_OUT->DEST. */
3457 redirect_eh_edge_1 (e_in, e_out->dest, false);
3458 redirect_edge_pred (e_out, e_in->src);
3459 e_out->flags = e_in->flags;
3460 e_out->probability = e_in->probability;
3461 e_out->count = e_in->count;
3467 /* Examine each landing pad block and see if it matches unsplit_eh. */
3470 unsplit_all_eh (void)
3472 bool changed = false;
3476 for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
3478 changed |= unsplit_eh (lp);
3483 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
3484 to OLD_BB to NEW_BB; return true on success, false on failure.
3486 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
3487 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
3488 Virtual PHIs may be deleted and marked for renaming. */
3491 cleanup_empty_eh_merge_phis (basic_block new_bb, basic_block old_bb,
3492 edge old_bb_out, bool change_region)
3494 gimple_stmt_iterator ngsi, ogsi;
3497 bitmap rename_virts;
3498 bitmap ophi_handled;
3500 FOR_EACH_EDGE (e, ei, old_bb->preds)
3501 redirect_edge_var_map_clear (e);
3503 ophi_handled = BITMAP_ALLOC (NULL);
3504 rename_virts = BITMAP_ALLOC (NULL);
3506 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
3507 for the edges we're going to move. */
3508 for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); gsi_next (&ngsi))
3510 gimple ophi, nphi = gsi_stmt (ngsi);
3513 nresult = gimple_phi_result (nphi);
3514 nop = gimple_phi_arg_def (nphi, old_bb_out->dest_idx);
3516 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
3517 the source ssa_name. */
3519 for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
3521 ophi = gsi_stmt (ogsi);
3522 if (gimple_phi_result (ophi) == nop)
3527 /* If we did find the corresponding PHI, copy those inputs. */
3530 bitmap_set_bit (ophi_handled, SSA_NAME_VERSION (nop));
3531 FOR_EACH_EDGE (e, ei, old_bb->preds)
3536 if ((e->flags & EDGE_EH) == 0)
3538 oop = gimple_phi_arg_def (ophi, e->dest_idx);
3539 oloc = gimple_phi_arg_location (ophi, e->dest_idx);
3540 redirect_edge_var_map_add (e, nresult, oop, oloc);
3543 /* If we didn't find the PHI, but it's a VOP, remember to rename
3544 it later, assuming all other tests succeed. */
3545 else if (!is_gimple_reg (nresult))
3546 bitmap_set_bit (rename_virts, SSA_NAME_VERSION (nresult));
3547 /* If we didn't find the PHI, and it's a real variable, we know
3548 from the fact that OLD_BB is tree_empty_eh_handler_p that the
3549 variable is unchanged from input to the block and we can simply
3550 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
3554 = gimple_phi_arg_location (nphi, old_bb_out->dest_idx);
3555 FOR_EACH_EDGE (e, ei, old_bb->preds)
3556 redirect_edge_var_map_add (e, nresult, nop, nloc);
3560 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
3561 we don't know what values from the other edges into NEW_BB to use. */
3562 for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
3564 gimple ophi = gsi_stmt (ogsi);
3565 tree oresult = gimple_phi_result (ophi);
3566 if (!bitmap_bit_p (ophi_handled, SSA_NAME_VERSION (oresult)))
3570 /* At this point we know that the merge will succeed. Remove the PHI
3571 nodes for the virtuals that we want to rename. */
3572 if (!bitmap_empty_p (rename_virts))
3574 for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); )
3576 gimple nphi = gsi_stmt (ngsi);
3577 tree nresult = gimple_phi_result (nphi);
3578 if (bitmap_bit_p (rename_virts, SSA_NAME_VERSION (nresult)))
3580 mark_virtual_phi_result_for_renaming (nphi);
3581 remove_phi_node (&ngsi, true);
3588 /* Finally, move the edges and update the PHIs. */
3589 for (ei = ei_start (old_bb->preds); (e = ei_safe_edge (ei)); )
3590 if (e->flags & EDGE_EH)
3592 redirect_eh_edge_1 (e, new_bb, change_region);
3593 redirect_edge_succ (e, new_bb);
3594 flush_pending_stmts (e);
3599 BITMAP_FREE (ophi_handled);
3600 BITMAP_FREE (rename_virts);
3604 FOR_EACH_EDGE (e, ei, old_bb->preds)
3605 redirect_edge_var_map_clear (e);
3606 BITMAP_FREE (ophi_handled);
3607 BITMAP_FREE (rename_virts);
3611 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
3612 old region to NEW_REGION at BB. */
3615 cleanup_empty_eh_move_lp (basic_block bb, edge e_out,
3616 eh_landing_pad lp, eh_region new_region)
3618 gimple_stmt_iterator gsi;
3621 for (pp = &lp->region->landing_pads; *pp != lp; pp = &(*pp)->next_lp)
3625 lp->region = new_region;
3626 lp->next_lp = new_region->landing_pads;
3627 new_region->landing_pads = lp;
3629 /* Delete the RESX that was matched within the empty handler block. */
3630 gsi = gsi_last_bb (bb);
3631 mark_virtual_ops_for_renaming (gsi_stmt (gsi));
3632 gsi_remove (&gsi, true);
3634 /* Clean up E_OUT for the fallthru. */
3635 e_out->flags = (e_out->flags & ~EDGE_EH) | EDGE_FALLTHRU;
3636 e_out->probability = REG_BR_PROB_BASE;
3639 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
3640 unsplitting than unsplit_eh was prepared to handle, e.g. when
3641 multiple incoming edges and phis are involved. */
3644 cleanup_empty_eh_unsplit (basic_block bb, edge e_out, eh_landing_pad lp)
3646 gimple_stmt_iterator gsi;
3649 /* We really ought not have totally lost everything following
3650 a landing pad label. Given that BB is empty, there had better
3652 gcc_assert (e_out != NULL);
3654 /* The destination block must not already have a landing pad
3655 for a different region. */
3657 for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
3659 gimple stmt = gsi_stmt (gsi);
3662 if (gimple_code (stmt) != GIMPLE_LABEL)
3664 lab = gimple_label_label (stmt);
3665 lp_nr = EH_LANDING_PAD_NR (lab);
3666 if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
3670 /* Attempt to move the PHIs into the successor block. */
3671 if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, false))
3673 if (dump_file && (dump_flags & TDF_DETAILS))
3675 "Unsplit EH landing pad %d to block %i "
3676 "(via cleanup_empty_eh).\n",
3677 lp->index, e_out->dest->index);
3684 /* Examine the block associated with LP to determine if it's an empty
3685 handler for its EH region. If so, attempt to redirect EH edges to
3686 an outer region. Return true the CFG was updated in any way. This
3687 is similar to jump forwarding, just across EH edges. */
3690 cleanup_empty_eh (eh_landing_pad lp)
3692 basic_block bb = label_to_block (lp->post_landing_pad);
3693 gimple_stmt_iterator gsi;
3695 eh_region new_region;
3698 bool has_non_eh_pred;
3701 /* There can be zero or one edges out of BB. This is the quickest test. */
3702 switch (EDGE_COUNT (bb->succs))
3708 e_out = EDGE_SUCC (bb, 0);
3713 gsi = gsi_after_labels (bb);
3715 /* Make sure to skip debug statements. */
3716 if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
3717 gsi_next_nondebug (&gsi);
3719 /* If the block is totally empty, look for more unsplitting cases. */
3720 if (gsi_end_p (gsi))
3721 return cleanup_empty_eh_unsplit (bb, e_out, lp);
3723 /* The block should consist only of a single RESX statement. */
3724 resx = gsi_stmt (gsi);
3725 if (!is_gimple_resx (resx))
3727 gcc_assert (gsi_one_before_end_p (gsi));
3729 /* Determine if there are non-EH edges, or resx edges into the handler. */
3730 has_non_eh_pred = false;
3731 FOR_EACH_EDGE (e, ei, bb->preds)
3732 if (!(e->flags & EDGE_EH))
3733 has_non_eh_pred = true;
3735 /* Find the handler that's outer of the empty handler by looking at
3736 where the RESX instruction was vectored. */
3737 new_lp_nr = lookup_stmt_eh_lp (resx);
3738 new_region = get_eh_region_from_lp_number (new_lp_nr);
3740 /* If there's no destination region within the current function,
3741 redirection is trivial via removing the throwing statements from
3742 the EH region, removing the EH edges, and allowing the block
3743 to go unreachable. */
3744 if (new_region == NULL)
3746 gcc_assert (e_out == NULL);
3747 for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
3748 if (e->flags & EDGE_EH)
3750 gimple stmt = last_stmt (e->src);
3751 remove_stmt_from_eh_lp (stmt);
3759 /* If the destination region is a MUST_NOT_THROW, allow the runtime
3760 to handle the abort and allow the blocks to go unreachable. */
3761 if (new_region->type == ERT_MUST_NOT_THROW)
3763 for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
3764 if (e->flags & EDGE_EH)
3766 gimple stmt = last_stmt (e->src);
3767 remove_stmt_from_eh_lp (stmt);
3768 add_stmt_to_eh_lp (stmt, new_lp_nr);
3776 /* Try to redirect the EH edges and merge the PHIs into the destination
3777 landing pad block. If the merge succeeds, we'll already have redirected
3778 all the EH edges. The handler itself will go unreachable if there were
3780 if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, true))
3783 /* Finally, if all input edges are EH edges, then we can (potentially)
3784 reduce the number of transfers from the runtime by moving the landing
3785 pad from the original region to the new region. This is a win when
3786 we remove the last CLEANUP region along a particular exception
3787 propagation path. Since nothing changes except for the region with
3788 which the landing pad is associated, the PHI nodes do not need to be
3790 if (!has_non_eh_pred)
3792 cleanup_empty_eh_move_lp (bb, e_out, lp, new_region);
3793 if (dump_file && (dump_flags & TDF_DETAILS))
3794 fprintf (dump_file, "Empty EH handler %i moved to EH region %i.\n",
3795 lp->index, new_region->index);
3797 /* ??? The CFG didn't change, but we may have rendered the
3798 old EH region unreachable. Trigger a cleanup there. */
3805 if (dump_file && (dump_flags & TDF_DETAILS))
3806 fprintf (dump_file, "Empty EH handler %i removed.\n", lp->index);
3807 remove_eh_landing_pad (lp);
3811 /* Do a post-order traversal of the EH region tree. Examine each
3812 post_landing_pad block and see if we can eliminate it as empty. */
3815 cleanup_all_empty_eh (void)
3817 bool changed = false;
3821 for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
3823 changed |= cleanup_empty_eh (lp);
3828 /* Perform cleanups and lowering of exception handling
3829 1) cleanups regions with handlers doing nothing are optimized out
3830 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
3831 3) Info about regions that are containing instructions, and regions
3832 reachable via local EH edges is collected
3833 4) Eh tree is pruned for regions no longer neccesary.
3835 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
3836 Unify those that have the same failure decl and locus.
3840 execute_cleanup_eh (void)
3842 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
3843 looking up unreachable landing pads. */
3844 remove_unreachable_handlers ();
3846 /* Watch out for the region tree vanishing due to all unreachable. */
3847 if (cfun->eh->region_tree && optimize)
3849 bool changed = false;
3851 changed |= unsplit_all_eh ();
3852 changed |= cleanup_all_empty_eh ();
3856 free_dominance_info (CDI_DOMINATORS);
3857 free_dominance_info (CDI_POST_DOMINATORS);
3859 /* We delayed all basic block deletion, as we may have performed
3860 cleanups on EH edges while non-EH edges were still present. */
3861 delete_unreachable_blocks ();
3863 /* We manipulated the landing pads. Remove any region that no
3864 longer has a landing pad. */
3865 remove_unreachable_handlers_no_lp ();
3867 return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals;
3875 gate_cleanup_eh (void)
3877 return cfun->eh != NULL && cfun->eh->region_tree != NULL;
3880 struct gimple_opt_pass pass_cleanup_eh = {
3883 "ehcleanup", /* name */
3884 gate_cleanup_eh, /* gate */
3885 execute_cleanup_eh, /* execute */
3888 0, /* static_pass_number */
3889 TV_TREE_EH, /* tv_id */
3890 PROP_gimple_lcf, /* properties_required */
3891 0, /* properties_provided */
3892 0, /* properties_destroyed */
3893 0, /* todo_flags_start */
3894 TODO_dump_func /* todo_flags_finish */
3898 /* Verify that BB containing STMT as the last statement, has precisely the
3899 edge that make_eh_edges would create. */
3902 verify_eh_edges (gimple stmt)
3904 basic_block bb = gimple_bb (stmt);
3905 eh_landing_pad lp = NULL;
3910 lp_nr = lookup_stmt_eh_lp (stmt);
3912 lp = get_eh_landing_pad_from_number (lp_nr);
3915 FOR_EACH_EDGE (e, ei, bb->succs)
3917 if (e->flags & EDGE_EH)
3921 error ("BB %i has multiple EH edges", bb->index);
3933 error ("BB %i can not throw but has an EH edge", bb->index);
3939 if (!stmt_could_throw_p (stmt))
3941 error ("BB %i last statement has incorrectly set lp", bb->index);
3945 if (eh_edge == NULL)
3947 error ("BB %i is missing an EH edge", bb->index);
3951 if (eh_edge->dest != label_to_block (lp->post_landing_pad))
3953 error ("Incorrect EH edge %i->%i", bb->index, eh_edge->dest->index);
3960 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
3963 verify_eh_dispatch_edge (gimple stmt)
3967 basic_block src, dst;
3968 bool want_fallthru = true;
3972 r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
3973 src = gimple_bb (stmt);
3975 FOR_EACH_EDGE (e, ei, src->succs)
3976 gcc_assert (e->aux == NULL);
3981 for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
3983 dst = label_to_block (c->label);
3984 e = find_edge (src, dst);
3987 error ("BB %i is missing an edge", src->index);
3992 /* A catch-all handler doesn't have a fallthru. */
3993 if (c->type_list == NULL)
3995 want_fallthru = false;
4001 case ERT_ALLOWED_EXCEPTIONS:
4002 dst = label_to_block (r->u.allowed.label);
4003 e = find_edge (src, dst);
4006 error ("BB %i is missing an edge", src->index);
4017 FOR_EACH_EDGE (e, ei, src->succs)
4019 if (e->flags & EDGE_FALLTHRU)
4021 if (fall_edge != NULL)
4023 error ("BB %i too many fallthru edges", src->index);
4032 error ("BB %i has incorrect edge", src->index);
4036 if ((fall_edge != NULL) ^ want_fallthru)
4038 error ("BB %i has incorrect fallthru edge", src->index);