1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
29 #include "pointer-set.h"
30 #include "tree-flow.h"
31 #include "tree-dump.h"
32 #include "tree-inline.h"
33 #include "tree-iterator.h"
34 #include "tree-pass.h"
36 #include "langhooks.h"
38 #include "diagnostic-core.h"
42 /* In some instances a tree and a gimple need to be stored in a same table,
43 i.e. in hash tables. This is a structure to do this. */
44 typedef union {tree
*tp
; tree t
; gimple g
;} treemple
;
46 /* Nonzero if we are using EH to handle cleanups. */
47 static int using_eh_for_cleanups_p
= 0;
50 using_eh_for_cleanups (void)
52 using_eh_for_cleanups_p
= 1;
55 /* Misc functions used in this file. */
57 /* Remember and lookup EH landing pad data for arbitrary statements.
58 Really this means any statement that could_throw_p. We could
59 stuff this information into the stmt_ann data structure, but:
61 (1) We absolutely rely on this information being kept until
62 we get to rtl. Once we're done with lowering here, if we lose
63 the information there's no way to recover it!
65 (2) There are many more statements that *cannot* throw as
66 compared to those that can. We should be saving some amount
67 of space by only allocating memory for those that can throw. */
69 /* Add statement T in function IFUN to landing pad NUM. */
72 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple t
, int num
)
74 struct throw_stmt_node
*n
;
77 gcc_assert (num
!= 0);
79 n
= ggc_alloc_throw_stmt_node ();
83 if (!get_eh_throw_stmt_table (ifun
))
84 set_eh_throw_stmt_table (ifun
, htab_create_ggc (31, struct_ptr_hash
,
88 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), n
, INSERT
);
93 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
96 add_stmt_to_eh_lp (gimple t
, int num
)
98 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
101 /* Add statement T to the single EH landing pad in REGION. */
104 record_stmt_eh_region (eh_region region
, gimple t
)
108 if (region
->type
== ERT_MUST_NOT_THROW
)
109 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
112 eh_landing_pad lp
= region
->landing_pads
;
114 lp
= gen_eh_landing_pad (region
);
116 gcc_assert (lp
->next_lp
== NULL
);
117 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
122 /* Remove statement T in function IFUN from its EH landing pad. */
125 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple t
)
127 struct throw_stmt_node dummy
;
130 if (!get_eh_throw_stmt_table (ifun
))
134 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), &dummy
,
138 htab_clear_slot (get_eh_throw_stmt_table (ifun
), slot
);
146 /* Remove statement T in the current function (cfun) from its
150 remove_stmt_from_eh_lp (gimple t
)
152 return remove_stmt_from_eh_lp_fn (cfun
, t
);
155 /* Determine if statement T is inside an EH region in function IFUN.
156 Positive numbers indicate a landing pad index; negative numbers
157 indicate a MUST_NOT_THROW region index; zero indicates that the
158 statement is not recorded in the region table. */
161 lookup_stmt_eh_lp_fn (struct function
*ifun
, gimple t
)
163 struct throw_stmt_node
*p
, n
;
165 if (ifun
->eh
->throw_stmt_table
== NULL
)
169 p
= (struct throw_stmt_node
*) htab_find (ifun
->eh
->throw_stmt_table
, &n
);
170 return p
? p
->lp_nr
: 0;
173 /* Likewise, but always use the current function. */
176 lookup_stmt_eh_lp (gimple t
)
178 /* We can get called from initialized data when -fnon-call-exceptions
179 is on; prevent crash. */
182 return lookup_stmt_eh_lp_fn (cfun
, t
);
185 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
186 nodes and LABEL_DECL nodes. We will use this during the second phase to
187 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
189 struct finally_tree_node
191 /* When storing a GIMPLE_TRY, we have to record a gimple. However
192 when deciding whether a GOTO to a certain LABEL_DECL (which is a
193 tree) leaves the TRY block, its necessary to record a tree in
194 this field. Thus a treemple is used. */
199 /* Note that this table is *not* marked GTY. It is short-lived. */
200 static htab_t finally_tree
;
203 record_in_finally_tree (treemple child
, gimple parent
)
205 struct finally_tree_node
*n
;
208 n
= XNEW (struct finally_tree_node
);
212 slot
= htab_find_slot (finally_tree
, n
, INSERT
);
218 collect_finally_tree (gimple stmt
, gimple region
);
220 /* Go through the gimple sequence. Works with collect_finally_tree to
221 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
224 collect_finally_tree_1 (gimple_seq seq
, gimple region
)
226 gimple_stmt_iterator gsi
;
228 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
229 collect_finally_tree (gsi_stmt (gsi
), region
);
233 collect_finally_tree (gimple stmt
, gimple region
)
237 switch (gimple_code (stmt
))
240 temp
.t
= gimple_label_label (stmt
);
241 record_in_finally_tree (temp
, region
);
245 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
248 record_in_finally_tree (temp
, region
);
249 collect_finally_tree_1 (gimple_try_eval (stmt
), stmt
);
250 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
252 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
254 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
255 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
260 collect_finally_tree_1 (gimple_catch_handler (stmt
), region
);
263 case GIMPLE_EH_FILTER
:
264 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
268 collect_finally_tree_1 (gimple_eh_else_n_body (stmt
), region
);
269 collect_finally_tree_1 (gimple_eh_else_e_body (stmt
), region
);
273 /* A type, a decl, or some kind of statement that we're not
274 interested in. Don't walk them. */
280 /* Use the finally tree to determine if a jump from START to TARGET
281 would leave the try_finally node that START lives in. */
284 outside_finally_tree (treemple start
, gimple target
)
286 struct finally_tree_node n
, *p
;
291 p
= (struct finally_tree_node
*) htab_find (finally_tree
, &n
);
296 while (start
.g
!= target
);
301 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
302 nodes into a set of gotos, magic labels, and eh regions.
303 The eh region creation is straight-forward, but frobbing all the gotos
304 and such into shape isn't. */
306 /* The sequence into which we record all EH stuff. This will be
307 placed at the end of the function when we're all done. */
308 static gimple_seq eh_seq
;
310 /* Record whether an EH region contains something that can throw,
311 indexed by EH region number. */
312 static bitmap eh_region_may_contain_throw_map
;
314 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
315 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
316 The idea is to record a gimple statement for everything except for
317 the conditionals, which get their labels recorded. Since labels are
318 of type 'tree', we need this node to store both gimple and tree
319 objects. REPL_STMT is the sequence used to replace the goto/return
320 statement. CONT_STMT is used to store the statement that allows
321 the return/goto to jump to the original destination. */
323 struct goto_queue_node
326 gimple_seq repl_stmt
;
329 /* This is used when index >= 0 to indicate that stmt is a label (as
330 opposed to a goto stmt). */
334 /* State of the world while lowering. */
338 /* What's "current" while constructing the eh region tree. These
339 correspond to variables of the same name in cfun->eh, which we
340 don't have easy access to. */
341 eh_region cur_region
;
343 /* What's "current" for the purposes of __builtin_eh_pointer. For
344 a CATCH, this is the associated TRY. For an EH_FILTER, this is
345 the associated ALLOWED_EXCEPTIONS, etc. */
346 eh_region ehp_region
;
348 /* Processing of TRY_FINALLY requires a bit more state. This is
349 split out into a separate structure so that we don't have to
350 copy so much when processing other nodes. */
351 struct leh_tf_state
*tf
;
356 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
357 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
358 this so that outside_finally_tree can reliably reference the tree used
359 in the collect_finally_tree data structures. */
360 gimple try_finally_expr
;
363 /* While lowering a top_p usually it is expanded into multiple statements,
364 thus we need the following field to store them. */
365 gimple_seq top_p_seq
;
367 /* The state outside this try_finally node. */
368 struct leh_state
*outer
;
370 /* The exception region created for it. */
373 /* The goto queue. */
374 struct goto_queue_node
*goto_queue
;
375 size_t goto_queue_size
;
376 size_t goto_queue_active
;
378 /* Pointer map to help in searching goto_queue when it is large. */
379 struct pointer_map_t
*goto_queue_map
;
381 /* The set of unique labels seen as entries in the goto queue. */
382 VEC(tree
,heap
) *dest_array
;
384 /* A label to be added at the end of the completed transformed
385 sequence. It will be set if may_fallthru was true *at one time*,
386 though subsequent transformations may have cleared that flag. */
389 /* True if it is possible to fall out the bottom of the try block.
390 Cleared if the fallthru is converted to a goto. */
393 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
396 /* True if the finally block can receive an exception edge.
397 Cleared if the exception case is handled by code duplication. */
401 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gimple
);
403 /* Search for STMT in the goto queue. Return the replacement,
404 or null if the statement isn't in the queue. */
406 #define LARGE_GOTO_QUEUE 20
408 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq seq
);
411 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
416 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
418 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
419 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
420 return tf
->goto_queue
[i
].repl_stmt
;
424 /* If we have a large number of entries in the goto_queue, create a
425 pointer map and use that for searching. */
427 if (!tf
->goto_queue_map
)
429 tf
->goto_queue_map
= pointer_map_create ();
430 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
432 slot
= pointer_map_insert (tf
->goto_queue_map
,
433 tf
->goto_queue
[i
].stmt
.g
);
434 gcc_assert (*slot
== NULL
);
435 *slot
= &tf
->goto_queue
[i
];
439 slot
= pointer_map_contains (tf
->goto_queue_map
, stmt
.g
);
441 return (((struct goto_queue_node
*) *slot
)->repl_stmt
);
446 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
447 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
448 then we can just splat it in, otherwise we add the new stmts immediately
449 after the GIMPLE_COND and redirect. */
452 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
453 gimple_stmt_iterator
*gsi
)
458 location_t loc
= gimple_location (gsi_stmt (*gsi
));
461 new_seq
= find_goto_replacement (tf
, temp
);
465 if (gimple_seq_singleton_p (new_seq
)
466 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
468 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
472 label
= create_artificial_label (loc
);
473 /* Set the new label for the GIMPLE_COND */
476 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
477 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
480 /* The real work of replace_goto_queue. Returns with TSI updated to
481 point to the next statement. */
483 static void replace_goto_queue_stmt_list (gimple_seq
, struct leh_tf_state
*);
486 replace_goto_queue_1 (gimple stmt
, struct leh_tf_state
*tf
,
487 gimple_stmt_iterator
*gsi
)
493 switch (gimple_code (stmt
))
498 seq
= find_goto_replacement (tf
, temp
);
501 gsi_insert_seq_before (gsi
, gimple_seq_copy (seq
), GSI_SAME_STMT
);
502 gsi_remove (gsi
, false);
508 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
509 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
513 replace_goto_queue_stmt_list (gimple_try_eval (stmt
), tf
);
514 replace_goto_queue_stmt_list (gimple_try_cleanup (stmt
), tf
);
517 replace_goto_queue_stmt_list (gimple_catch_handler (stmt
), tf
);
519 case GIMPLE_EH_FILTER
:
520 replace_goto_queue_stmt_list (gimple_eh_filter_failure (stmt
), tf
);
523 replace_goto_queue_stmt_list (gimple_eh_else_n_body (stmt
), tf
);
524 replace_goto_queue_stmt_list (gimple_eh_else_e_body (stmt
), tf
);
528 /* These won't have gotos in them. */
535 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
538 replace_goto_queue_stmt_list (gimple_seq seq
, struct leh_tf_state
*tf
)
540 gimple_stmt_iterator gsi
= gsi_start (seq
);
542 while (!gsi_end_p (gsi
))
543 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
546 /* Replace all goto queue members. */
549 replace_goto_queue (struct leh_tf_state
*tf
)
551 if (tf
->goto_queue_active
== 0)
553 replace_goto_queue_stmt_list (tf
->top_p_seq
, tf
);
554 replace_goto_queue_stmt_list (eh_seq
, tf
);
557 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
558 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
562 record_in_goto_queue (struct leh_tf_state
*tf
,
568 struct goto_queue_node
*q
;
570 gcc_assert (!tf
->goto_queue_map
);
572 active
= tf
->goto_queue_active
;
573 size
= tf
->goto_queue_size
;
576 size
= (size
? size
* 2 : 32);
577 tf
->goto_queue_size
= size
;
579 = XRESIZEVEC (struct goto_queue_node
, tf
->goto_queue
, size
);
582 q
= &tf
->goto_queue
[active
];
583 tf
->goto_queue_active
= active
+ 1;
585 memset (q
, 0, sizeof (*q
));
588 q
->is_label
= is_label
;
591 /* Record the LABEL label in the goto queue contained in TF.
595 record_in_goto_queue_label (struct leh_tf_state
*tf
, treemple stmt
, tree label
)
598 treemple temp
, new_stmt
;
603 /* Computed and non-local gotos do not get processed. Given
604 their nature we can neither tell whether we've escaped the
605 finally block nor redirect them if we knew. */
606 if (TREE_CODE (label
) != LABEL_DECL
)
609 /* No need to record gotos that don't leave the try block. */
611 if (!outside_finally_tree (temp
, tf
->try_finally_expr
))
614 if (! tf
->dest_array
)
616 tf
->dest_array
= VEC_alloc (tree
, heap
, 10);
617 VEC_quick_push (tree
, tf
->dest_array
, label
);
622 int n
= VEC_length (tree
, tf
->dest_array
);
623 for (index
= 0; index
< n
; ++index
)
624 if (VEC_index (tree
, tf
->dest_array
, index
) == label
)
627 VEC_safe_push (tree
, heap
, tf
->dest_array
, label
);
630 /* In the case of a GOTO we want to record the destination label,
631 since with a GIMPLE_COND we have an easy access to the then/else
634 record_in_goto_queue (tf
, new_stmt
, index
, true);
637 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
638 node, and if so record that fact in the goto queue associated with that
642 maybe_record_in_goto_queue (struct leh_state
*state
, gimple stmt
)
644 struct leh_tf_state
*tf
= state
->tf
;
650 switch (gimple_code (stmt
))
653 new_stmt
.tp
= gimple_op_ptr (stmt
, 2);
654 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_true_label (stmt
));
655 new_stmt
.tp
= gimple_op_ptr (stmt
, 3);
656 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_false_label (stmt
));
660 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
));
664 tf
->may_return
= true;
666 record_in_goto_queue (tf
, new_stmt
, -1, false);
675 #ifdef ENABLE_CHECKING
676 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
677 was in fact structured, and we've not yet done jump threading, then none
678 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
681 verify_norecord_switch_expr (struct leh_state
*state
, gimple switch_expr
)
683 struct leh_tf_state
*tf
= state
->tf
;
689 n
= gimple_switch_num_labels (switch_expr
);
691 for (i
= 0; i
< n
; ++i
)
694 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
696 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
700 #define verify_norecord_switch_expr(state, switch_expr)
703 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
704 non-null, insert it before the new branch. */
707 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
)
711 /* In the case of a return, the queue node must be a gimple statement. */
712 gcc_assert (!q
->is_label
);
714 /* Note that the return value may have already been computed, e.g.,
727 should return 0, not 1. We don't have to do anything to make
728 this happens because the return value has been placed in the
729 RESULT_DECL already. */
731 q
->cont_stmt
= q
->stmt
.g
;
734 q
->repl_stmt
= gimple_seq_alloc ();
737 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
739 x
= gimple_build_goto (finlab
);
740 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
743 /* Similar, but easier, for GIMPLE_GOTO. */
746 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
747 struct leh_tf_state
*tf
)
751 gcc_assert (q
->is_label
);
753 q
->repl_stmt
= gimple_seq_alloc ();
755 q
->cont_stmt
= gimple_build_goto (VEC_index (tree
, tf
->dest_array
, q
->index
));
758 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
760 x
= gimple_build_goto (finlab
);
761 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
764 /* Emit a standard landing pad sequence into SEQ for REGION. */
767 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
769 eh_landing_pad lp
= region
->landing_pads
;
773 lp
= gen_eh_landing_pad (region
);
775 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
776 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
778 x
= gimple_build_label (lp
->post_landing_pad
);
779 gimple_seq_add_stmt (seq
, x
);
782 /* Emit a RESX statement into SEQ for REGION. */
785 emit_resx (gimple_seq
*seq
, eh_region region
)
787 gimple x
= gimple_build_resx (region
->index
);
788 gimple_seq_add_stmt (seq
, x
);
790 record_stmt_eh_region (region
->outer
, x
);
793 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
796 emit_eh_dispatch (gimple_seq
*seq
, eh_region region
)
798 gimple x
= gimple_build_eh_dispatch (region
->index
);
799 gimple_seq_add_stmt (seq
, x
);
802 /* Note that the current EH region may contain a throw, or a
803 call to a function which itself may contain a throw. */
806 note_eh_region_may_contain_throw (eh_region region
)
808 while (bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
))
810 if (region
->type
== ERT_MUST_NOT_THROW
)
812 region
= region
->outer
;
818 /* Check if REGION has been marked as containing a throw. If REGION is
819 NULL, this predicate is false. */
822 eh_region_may_contain_throw (eh_region r
)
824 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
827 /* We want to transform
828 try { body; } catch { stuff; }
838 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
839 should be placed before the second operand, or NULL. OVER is
840 an existing label that should be put at the exit, or NULL. */
843 frob_into_branch_around (gimple tp
, eh_region region
, tree over
)
846 gimple_seq cleanup
, result
;
847 location_t loc
= gimple_location (tp
);
849 cleanup
= gimple_try_cleanup (tp
);
850 result
= gimple_try_eval (tp
);
853 emit_post_landing_pad (&eh_seq
, region
);
855 if (gimple_seq_may_fallthru (cleanup
))
858 over
= create_artificial_label (loc
);
859 x
= gimple_build_goto (over
);
860 gimple_seq_add_stmt (&cleanup
, x
);
862 gimple_seq_add_seq (&eh_seq
, cleanup
);
866 x
= gimple_build_label (over
);
867 gimple_seq_add_stmt (&result
, x
);
872 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
873 Make sure to record all new labels found. */
876 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
)
878 gimple region
= NULL
;
881 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
884 region
= outer_state
->tf
->try_finally_expr
;
885 collect_finally_tree_1 (new_seq
, region
);
890 /* A subroutine of lower_try_finally. Create a fallthru label for
891 the given try_finally state. The only tricky bit here is that
892 we have to make sure to record the label in our outer context. */
895 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
897 tree label
= tf
->fallthru_label
;
902 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
903 tf
->fallthru_label
= label
;
907 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
913 /* A subroutine of lower_try_finally. If FINALLY consits of a
914 GIMPLE_EH_ELSE node, return it. */
917 get_eh_else (gimple_seq finally
)
919 gimple x
= gimple_seq_first_stmt (finally
);
920 if (gimple_code (x
) == GIMPLE_EH_ELSE
)
922 gcc_assert (gimple_seq_singleton_p (finally
));
928 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
929 langhook returns non-null, then the language requires that the exception
930 path out of a try_finally be treated specially. To wit: the code within
931 the finally block may not itself throw an exception. We have two choices
932 here. First we can duplicate the finally block and wrap it in a
933 must_not_throw region. Second, we can generate code like
938 if (fintmp == eh_edge)
939 protect_cleanup_actions;
942 where "fintmp" is the temporary used in the switch statement generation
943 alternative considered below. For the nonce, we always choose the first
946 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
949 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
950 struct leh_state
*this_state
,
951 struct leh_tf_state
*tf
)
953 tree protect_cleanup_actions
;
954 gimple_stmt_iterator gsi
;
955 bool finally_may_fallthru
;
959 /* First check for nothing to do. */
960 if (lang_hooks
.eh_protect_cleanup_actions
== NULL
)
962 protect_cleanup_actions
= lang_hooks
.eh_protect_cleanup_actions ();
963 if (protect_cleanup_actions
== NULL
)
966 finally
= gimple_try_cleanup (tf
->top_p
);
967 eh_else
= get_eh_else (finally
);
969 /* Duplicate the FINALLY block. Only need to do this for try-finally,
970 and not for cleanups. If we've got an EH_ELSE, extract it now. */
973 finally
= gimple_eh_else_e_body (eh_else
);
974 gimple_try_set_cleanup (tf
->top_p
, gimple_eh_else_n_body (eh_else
));
977 finally
= lower_try_finally_dup_block (finally
, outer_state
);
978 finally_may_fallthru
= gimple_seq_may_fallthru (finally
);
980 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
981 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
982 to be in an enclosing scope, but needs to be implemented at this level
983 to avoid a nesting violation (see wrap_temporary_cleanups in
984 cp/decl.c). Since it's logically at an outer level, we should call
985 terminate before we get to it, so strip it away before adding the
986 MUST_NOT_THROW filter. */
987 gsi
= gsi_start (finally
);
989 if (gimple_code (x
) == GIMPLE_TRY
990 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
991 && gimple_try_catch_is_cleanup (x
))
993 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
994 gsi_remove (&gsi
, false);
997 /* Wrap the block with protect_cleanup_actions as the action. */
998 x
= gimple_build_eh_must_not_throw (protect_cleanup_actions
);
999 x
= gimple_build_try (finally
, gimple_seq_alloc_with_stmt (x
),
1001 finally
= lower_eh_must_not_throw (outer_state
, x
);
1003 /* Drop all of this into the exception sequence. */
1004 emit_post_landing_pad (&eh_seq
, tf
->region
);
1005 gimple_seq_add_seq (&eh_seq
, finally
);
1006 if (finally_may_fallthru
)
1007 emit_resx (&eh_seq
, tf
->region
);
1009 /* Having now been handled, EH isn't to be considered with
1010 the rest of the outgoing edges. */
1011 tf
->may_throw
= false;
1014 /* A subroutine of lower_try_finally. We have determined that there is
1015 no fallthru edge out of the finally block. This means that there is
1016 no outgoing edge corresponding to any incoming edge. Restructure the
1017 try_finally node for this special case. */
1020 lower_try_finally_nofallthru (struct leh_state
*state
,
1021 struct leh_tf_state
*tf
)
1026 struct goto_queue_node
*q
, *qe
;
1028 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1030 /* We expect that tf->top_p is a GIMPLE_TRY. */
1031 finally
= gimple_try_cleanup (tf
->top_p
);
1032 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1034 x
= gimple_build_label (lab
);
1035 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1038 qe
= q
+ tf
->goto_queue_active
;
1041 do_return_redirection (q
, lab
, NULL
);
1043 do_goto_redirection (q
, lab
, NULL
, tf
);
1045 replace_goto_queue (tf
);
1047 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1048 eh_else
= get_eh_else (finally
);
1051 finally
= gimple_eh_else_n_body (eh_else
);
1052 lower_eh_constructs_1 (state
, finally
);
1053 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1057 finally
= gimple_eh_else_e_body (eh_else
);
1058 lower_eh_constructs_1 (state
, finally
);
1060 emit_post_landing_pad (&eh_seq
, tf
->region
);
1061 gimple_seq_add_seq (&eh_seq
, finally
);
1066 lower_eh_constructs_1 (state
, finally
);
1067 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1071 emit_post_landing_pad (&eh_seq
, tf
->region
);
1073 x
= gimple_build_goto (lab
);
1074 gimple_seq_add_stmt (&eh_seq
, x
);
1079 /* A subroutine of lower_try_finally. We have determined that there is
1080 exactly one destination of the finally block. Restructure the
1081 try_finally node for this special case. */
1084 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1086 struct goto_queue_node
*q
, *qe
;
1090 location_t loc
= gimple_location (tf
->try_finally_expr
);
1092 finally
= gimple_try_cleanup (tf
->top_p
);
1093 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1095 /* Since there's only one destination, and the destination edge can only
1096 either be EH or non-EH, that implies that all of our incoming edges
1097 are of the same type. Therefore we can lower EH_ELSE immediately. */
1098 x
= get_eh_else (finally
);
1102 finally
= gimple_eh_else_e_body (x
);
1104 finally
= gimple_eh_else_n_body (x
);
1107 lower_eh_constructs_1 (state
, finally
);
1111 /* Only reachable via the exception edge. Add the given label to
1112 the head of the FINALLY block. Append a RESX at the end. */
1113 emit_post_landing_pad (&eh_seq
, tf
->region
);
1114 gimple_seq_add_seq (&eh_seq
, finally
);
1115 emit_resx (&eh_seq
, tf
->region
);
1119 if (tf
->may_fallthru
)
1121 /* Only reachable via the fallthru edge. Do nothing but let
1122 the two blocks run together; we'll fall out the bottom. */
1123 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1127 finally_label
= create_artificial_label (loc
);
1128 x
= gimple_build_label (finally_label
);
1129 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1131 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1134 qe
= q
+ tf
->goto_queue_active
;
1138 /* Reachable by return expressions only. Redirect them. */
1140 do_return_redirection (q
, finally_label
, NULL
);
1141 replace_goto_queue (tf
);
1145 /* Reachable by goto expressions only. Redirect them. */
1147 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1148 replace_goto_queue (tf
);
1150 if (VEC_index (tree
, tf
->dest_array
, 0) == tf
->fallthru_label
)
1152 /* Reachable by goto to fallthru label only. Redirect it
1153 to the new label (already created, sadly), and do not
1154 emit the final branch out, or the fallthru label. */
1155 tf
->fallthru_label
= NULL
;
1160 /* Place the original return/goto to the original destination
1161 immediately after the finally block. */
1162 x
= tf
->goto_queue
[0].cont_stmt
;
1163 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1164 maybe_record_in_goto_queue (state
, x
);
1167 /* A subroutine of lower_try_finally. There are multiple edges incoming
1168 and outgoing from the finally block. Implement this by duplicating the
1169 finally block for every destination. */
1172 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1175 gimple_seq new_stmt
;
1179 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1181 finally
= gimple_try_cleanup (tf
->top_p
);
1183 /* Notice EH_ELSE, and simplify some of the remaining code
1184 by considering FINALLY to be the normal return path only. */
1185 eh_else
= get_eh_else (finally
);
1187 finally
= gimple_eh_else_n_body (eh_else
);
1189 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1192 if (tf
->may_fallthru
)
1194 seq
= lower_try_finally_dup_block (finally
, state
);
1195 lower_eh_constructs_1 (state
, seq
);
1196 gimple_seq_add_seq (&new_stmt
, seq
);
1198 tmp
= lower_try_finally_fallthru_label (tf
);
1199 x
= gimple_build_goto (tmp
);
1200 gimple_seq_add_stmt (&new_stmt
, x
);
1205 /* We don't need to copy the EH path of EH_ELSE,
1206 since it is only emitted once. */
1208 seq
= gimple_eh_else_e_body (eh_else
);
1210 seq
= lower_try_finally_dup_block (finally
, state
);
1211 lower_eh_constructs_1 (state
, seq
);
1213 emit_post_landing_pad (&eh_seq
, tf
->region
);
1214 gimple_seq_add_seq (&eh_seq
, seq
);
1215 emit_resx (&eh_seq
, tf
->region
);
1220 struct goto_queue_node
*q
, *qe
;
1221 int return_index
, index
;
1224 struct goto_queue_node
*q
;
1228 return_index
= VEC_length (tree
, tf
->dest_array
);
1229 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1232 qe
= q
+ tf
->goto_queue_active
;
1235 index
= q
->index
< 0 ? return_index
: q
->index
;
1237 if (!labels
[index
].q
)
1238 labels
[index
].q
= q
;
1241 for (index
= 0; index
< return_index
+ 1; index
++)
1245 q
= labels
[index
].q
;
1249 lab
= labels
[index
].label
1250 = create_artificial_label (tf_loc
);
1252 if (index
== return_index
)
1253 do_return_redirection (q
, lab
, NULL
);
1255 do_goto_redirection (q
, lab
, NULL
, tf
);
1257 x
= gimple_build_label (lab
);
1258 gimple_seq_add_stmt (&new_stmt
, x
);
1260 seq
= lower_try_finally_dup_block (finally
, state
);
1261 lower_eh_constructs_1 (state
, seq
);
1262 gimple_seq_add_seq (&new_stmt
, seq
);
1264 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1265 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1268 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1272 index
= q
->index
< 0 ? return_index
: q
->index
;
1274 if (labels
[index
].q
== q
)
1277 lab
= labels
[index
].label
;
1279 if (index
== return_index
)
1280 do_return_redirection (q
, lab
, NULL
);
1282 do_goto_redirection (q
, lab
, NULL
, tf
);
1285 replace_goto_queue (tf
);
1289 /* Need to link new stmts after running replace_goto_queue due
1290 to not wanting to process the same goto stmts twice. */
1291 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1294 /* A subroutine of lower_try_finally. There are multiple edges incoming
1295 and outgoing from the finally block. Implement this by instrumenting
1296 each incoming edge and creating a switch statement at the end of the
1297 finally block that branches to the appropriate destination. */
1300 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1302 struct goto_queue_node
*q
, *qe
;
1303 tree finally_tmp
, finally_label
;
1304 int return_index
, eh_index
, fallthru_index
;
1305 int nlabels
, ndests
, j
, last_case_index
;
1307 VEC (tree
,heap
) *case_label_vec
;
1308 gimple_seq switch_body
;
1313 struct pointer_map_t
*cont_map
= NULL
;
1314 /* The location of the TRY_FINALLY stmt. */
1315 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1316 /* The location of the finally block. */
1317 location_t finally_loc
;
1319 switch_body
= gimple_seq_alloc ();
1320 finally
= gimple_try_cleanup (tf
->top_p
);
1321 eh_else
= get_eh_else (finally
);
1323 /* Mash the TRY block to the head of the chain. */
1324 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1326 /* The location of the finally is either the last stmt in the finally
1327 block or the location of the TRY_FINALLY itself. */
1328 finally_loc
= gimple_seq_last_stmt (tf
->top_p_seq
) != NULL
?
1329 gimple_location (gimple_seq_last_stmt (tf
->top_p_seq
))
1332 /* Lower the finally block itself. */
1333 lower_eh_constructs_1 (state
, finally
);
1335 /* Prepare for switch statement generation. */
1336 nlabels
= VEC_length (tree
, tf
->dest_array
);
1337 return_index
= nlabels
;
1338 eh_index
= return_index
+ tf
->may_return
;
1339 fallthru_index
= eh_index
+ (tf
->may_throw
&& !eh_else
);
1340 ndests
= fallthru_index
+ tf
->may_fallthru
;
1342 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1343 finally_label
= create_artificial_label (finally_loc
);
1345 /* We use VEC_quick_push on case_label_vec throughout this function,
1346 since we know the size in advance and allocate precisely as muce
1348 case_label_vec
= VEC_alloc (tree
, heap
, ndests
);
1350 last_case_index
= 0;
1352 /* Begin inserting code for getting to the finally block. Things
1353 are done in this order to correspond to the sequence the code is
1356 if (tf
->may_fallthru
)
1358 x
= gimple_build_assign (finally_tmp
,
1359 build_int_cst (integer_type_node
,
1361 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1363 tmp
= build_int_cst (integer_type_node
, fallthru_index
);
1364 last_case
= build_case_label (tmp
, NULL
,
1365 create_artificial_label (tf_loc
));
1366 VEC_quick_push (tree
, case_label_vec
, last_case
);
1369 x
= gimple_build_label (CASE_LABEL (last_case
));
1370 gimple_seq_add_stmt (&switch_body
, x
);
1372 tmp
= lower_try_finally_fallthru_label (tf
);
1373 x
= gimple_build_goto (tmp
);
1374 gimple_seq_add_stmt (&switch_body
, x
);
1377 /* For EH_ELSE, emit the exception path (plus resx) now, then
1378 subsequently we only need consider the normal path. */
1383 finally
= gimple_eh_else_e_body (eh_else
);
1384 lower_eh_constructs_1 (state
, finally
);
1386 emit_post_landing_pad (&eh_seq
, tf
->region
);
1387 gimple_seq_add_seq (&eh_seq
, finally
);
1388 emit_resx (&eh_seq
, tf
->region
);
1391 finally
= gimple_eh_else_n_body (eh_else
);
1393 else if (tf
->may_throw
)
1395 emit_post_landing_pad (&eh_seq
, tf
->region
);
1397 x
= gimple_build_assign (finally_tmp
,
1398 build_int_cst (integer_type_node
, eh_index
));
1399 gimple_seq_add_stmt (&eh_seq
, x
);
1401 x
= gimple_build_goto (finally_label
);
1402 gimple_seq_add_stmt (&eh_seq
, x
);
1404 tmp
= build_int_cst (integer_type_node
, eh_index
);
1405 last_case
= build_case_label (tmp
, NULL
,
1406 create_artificial_label (tf_loc
));
1407 VEC_quick_push (tree
, case_label_vec
, last_case
);
1410 x
= gimple_build_label (CASE_LABEL (last_case
));
1411 gimple_seq_add_stmt (&eh_seq
, x
);
1412 emit_resx (&eh_seq
, tf
->region
);
1415 x
= gimple_build_label (finally_label
);
1416 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1418 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1420 /* Redirect each incoming goto edge. */
1422 qe
= q
+ tf
->goto_queue_active
;
1423 j
= last_case_index
+ tf
->may_return
;
1424 /* Prepare the assignments to finally_tmp that are executed upon the
1425 entrance through a particular edge. */
1430 unsigned int case_index
;
1432 mod
= gimple_seq_alloc ();
1436 x
= gimple_build_assign (finally_tmp
,
1437 build_int_cst (integer_type_node
,
1439 gimple_seq_add_stmt (&mod
, x
);
1440 do_return_redirection (q
, finally_label
, mod
);
1441 switch_id
= return_index
;
1445 x
= gimple_build_assign (finally_tmp
,
1446 build_int_cst (integer_type_node
, q
->index
));
1447 gimple_seq_add_stmt (&mod
, x
);
1448 do_goto_redirection (q
, finally_label
, mod
, tf
);
1449 switch_id
= q
->index
;
1452 case_index
= j
+ q
->index
;
1453 if (VEC_length (tree
, case_label_vec
) <= case_index
1454 || !VEC_index (tree
, case_label_vec
, case_index
))
1458 tmp
= build_int_cst (integer_type_node
, switch_id
);
1459 case_lab
= build_case_label (tmp
, NULL
,
1460 create_artificial_label (tf_loc
));
1461 /* We store the cont_stmt in the pointer map, so that we can recover
1462 it in the loop below. */
1464 cont_map
= pointer_map_create ();
1465 slot
= pointer_map_insert (cont_map
, case_lab
);
1466 *slot
= q
->cont_stmt
;
1467 VEC_quick_push (tree
, case_label_vec
, case_lab
);
1470 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1475 last_case
= VEC_index (tree
, case_label_vec
, j
);
1477 gcc_assert (last_case
);
1478 gcc_assert (cont_map
);
1480 slot
= pointer_map_contains (cont_map
, last_case
);
1482 cont_stmt
= *(gimple
*) slot
;
1484 x
= gimple_build_label (CASE_LABEL (last_case
));
1485 gimple_seq_add_stmt (&switch_body
, x
);
1486 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1487 maybe_record_in_goto_queue (state
, cont_stmt
);
1490 pointer_map_destroy (cont_map
);
1492 replace_goto_queue (tf
);
1494 /* Make sure that the last case is the default label, as one is required.
1495 Then sort the labels, which is also required in GIMPLE. */
1496 CASE_LOW (last_case
) = NULL
;
1497 sort_case_labels (case_label_vec
);
1499 /* Build the switch statement, setting last_case to be the default
1501 switch_stmt
= gimple_build_switch_vec (finally_tmp
, last_case
,
1503 gimple_set_location (switch_stmt
, finally_loc
);
1505 /* Need to link SWITCH_STMT after running replace_goto_queue
1506 due to not wanting to process the same goto stmts twice. */
1507 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1508 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1511 /* Decide whether or not we are going to duplicate the finally block.
1512 There are several considerations.
1514 First, if this is Java, then the finally block contains code
1515 written by the user. It has line numbers associated with it,
1516 so duplicating the block means it's difficult to set a breakpoint.
1517 Since controlling code generation via -g is verboten, we simply
1518 never duplicate code without optimization.
1520 Second, we'd like to prevent egregious code growth. One way to
1521 do this is to estimate the size of the finally block, multiply
1522 that by the number of copies we'd need to make, and compare against
1523 the estimate of the size of the switch machinery we'd have to add. */
1526 decide_copy_try_finally (int ndests
, bool may_throw
, gimple_seq finally
)
1528 int f_estimate
, sw_estimate
;
1531 /* If there's an EH_ELSE involved, the exception path is separate
1532 and really doesn't come into play for this computation. */
1533 eh_else
= get_eh_else (finally
);
1536 ndests
-= may_throw
;
1537 finally
= gimple_eh_else_n_body (eh_else
);
1543 /* Finally estimate N times, plus N gotos. */
1544 f_estimate
= count_insns_seq (finally
, &eni_size_weights
);
1545 f_estimate
= (f_estimate
+ 1) * ndests
;
1547 /* Switch statement (cost 10), N variable assignments, N gotos. */
1548 sw_estimate
= 10 + 2 * ndests
;
1550 /* Optimize for size clearly wants our best guess. */
1551 if (optimize_function_for_size_p (cfun
))
1552 return f_estimate
< sw_estimate
;
1554 /* ??? These numbers are completely made up so far. */
1556 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1558 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1561 /* REG is the enclosing region for a possible cleanup region, or the region
1562 itself. Returns TRUE if such a region would be unreachable.
1564 Cleanup regions within a must-not-throw region aren't actually reachable
1565 even if there are throwing stmts within them, because the personality
1566 routine will call terminate before unwinding. */
1569 cleanup_is_dead_in (eh_region reg
)
1571 while (reg
&& reg
->type
== ERT_CLEANUP
)
1573 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1576 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1577 to a sequence of labels and blocks, plus the exception region trees
1578 that record all the magic. This is complicated by the need to
1579 arrange for the FINALLY block to be executed on all exits. */
1582 lower_try_finally (struct leh_state
*state
, gimple tp
)
1584 struct leh_tf_state this_tf
;
1585 struct leh_state this_state
;
1587 gimple_seq old_eh_seq
;
1589 /* Process the try block. */
1591 memset (&this_tf
, 0, sizeof (this_tf
));
1592 this_tf
.try_finally_expr
= tp
;
1594 this_tf
.outer
= state
;
1595 if (using_eh_for_cleanups_p
&& !cleanup_is_dead_in (state
->cur_region
))
1597 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1598 this_state
.cur_region
= this_tf
.region
;
1602 this_tf
.region
= NULL
;
1603 this_state
.cur_region
= state
->cur_region
;
1606 this_state
.ehp_region
= state
->ehp_region
;
1607 this_state
.tf
= &this_tf
;
1609 old_eh_seq
= eh_seq
;
1612 lower_eh_constructs_1 (&this_state
, gimple_try_eval(tp
));
1614 /* Determine if the try block is escaped through the bottom. */
1615 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1617 /* Determine if any exceptions are possible within the try block. */
1619 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1620 if (this_tf
.may_throw
)
1621 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1623 /* Determine how many edges (still) reach the finally block. Or rather,
1624 how many destinations are reached by the finally block. Use this to
1625 determine how we process the finally block itself. */
1627 ndests
= VEC_length (tree
, this_tf
.dest_array
);
1628 ndests
+= this_tf
.may_fallthru
;
1629 ndests
+= this_tf
.may_return
;
1630 ndests
+= this_tf
.may_throw
;
1632 /* If the FINALLY block is not reachable, dike it out. */
1635 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1636 gimple_try_set_cleanup (tp
, NULL
);
1638 /* If the finally block doesn't fall through, then any destination
1639 we might try to impose there isn't reached either. There may be
1640 some minor amount of cleanup and redirection still needed. */
1641 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1642 lower_try_finally_nofallthru (state
, &this_tf
);
1644 /* We can easily special-case redirection to a single destination. */
1645 else if (ndests
== 1)
1646 lower_try_finally_onedest (state
, &this_tf
);
1647 else if (decide_copy_try_finally (ndests
, this_tf
.may_throw
,
1648 gimple_try_cleanup (tp
)))
1649 lower_try_finally_copy (state
, &this_tf
);
1651 lower_try_finally_switch (state
, &this_tf
);
1653 /* If someone requested we add a label at the end of the transformed
1655 if (this_tf
.fallthru_label
)
1657 /* This must be reached only if ndests == 0. */
1658 gimple x
= gimple_build_label (this_tf
.fallthru_label
);
1659 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1662 VEC_free (tree
, heap
, this_tf
.dest_array
);
1663 free (this_tf
.goto_queue
);
1664 if (this_tf
.goto_queue_map
)
1665 pointer_map_destroy (this_tf
.goto_queue_map
);
1667 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1668 If there was no old eh_seq, then the append is trivially already done. */
1672 eh_seq
= old_eh_seq
;
1675 gimple_seq new_eh_seq
= eh_seq
;
1676 eh_seq
= old_eh_seq
;
1677 gimple_seq_add_seq(&eh_seq
, new_eh_seq
);
1681 return this_tf
.top_p_seq
;
1684 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1685 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1686 exception region trees that records all the magic. */
1689 lower_catch (struct leh_state
*state
, gimple tp
)
1691 eh_region try_region
= NULL
;
1692 struct leh_state this_state
= *state
;
1693 gimple_stmt_iterator gsi
;
1697 location_t try_catch_loc
= gimple_location (tp
);
1699 if (flag_exceptions
)
1701 try_region
= gen_eh_region_try (state
->cur_region
);
1702 this_state
.cur_region
= try_region
;
1705 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1707 if (!eh_region_may_contain_throw (try_region
))
1708 return gimple_try_eval (tp
);
1711 emit_eh_dispatch (&new_seq
, try_region
);
1712 emit_resx (&new_seq
, try_region
);
1714 this_state
.cur_region
= state
->cur_region
;
1715 this_state
.ehp_region
= try_region
;
1718 for (gsi
= gsi_start (gimple_try_cleanup (tp
));
1726 gcatch
= gsi_stmt (gsi
);
1727 c
= gen_eh_region_catch (try_region
, gimple_catch_types (gcatch
));
1729 handler
= gimple_catch_handler (gcatch
);
1730 lower_eh_constructs_1 (&this_state
, handler
);
1732 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1733 x
= gimple_build_label (c
->label
);
1734 gimple_seq_add_stmt (&new_seq
, x
);
1736 gimple_seq_add_seq (&new_seq
, handler
);
1738 if (gimple_seq_may_fallthru (new_seq
))
1741 out_label
= create_artificial_label (try_catch_loc
);
1743 x
= gimple_build_goto (out_label
);
1744 gimple_seq_add_stmt (&new_seq
, x
);
1750 gimple_try_set_cleanup (tp
, new_seq
);
1752 return frob_into_branch_around (tp
, try_region
, out_label
);
1755 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1756 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1757 region trees that record all the magic. */
1760 lower_eh_filter (struct leh_state
*state
, gimple tp
)
1762 struct leh_state this_state
= *state
;
1763 eh_region this_region
= NULL
;
1767 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1769 if (flag_exceptions
)
1771 this_region
= gen_eh_region_allowed (state
->cur_region
,
1772 gimple_eh_filter_types (inner
));
1773 this_state
.cur_region
= this_region
;
1776 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1778 if (!eh_region_may_contain_throw (this_region
))
1779 return gimple_try_eval (tp
);
1782 this_state
.cur_region
= state
->cur_region
;
1783 this_state
.ehp_region
= this_region
;
1785 emit_eh_dispatch (&new_seq
, this_region
);
1786 emit_resx (&new_seq
, this_region
);
1788 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1789 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1790 gimple_seq_add_stmt (&new_seq
, x
);
1792 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure (inner
));
1793 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1795 gimple_try_set_cleanup (tp
, new_seq
);
1797 return frob_into_branch_around (tp
, this_region
, NULL
);
1800 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1801 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1802 plus the exception region trees that record all the magic. */
1805 lower_eh_must_not_throw (struct leh_state
*state
, gimple tp
)
1807 struct leh_state this_state
= *state
;
1809 if (flag_exceptions
)
1811 gimple inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1812 eh_region this_region
;
1814 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1815 this_region
->u
.must_not_throw
.failure_decl
1816 = gimple_eh_must_not_throw_fndecl (inner
);
1817 this_region
->u
.must_not_throw
.failure_loc
= gimple_location (tp
);
1819 /* In order to get mangling applied to this decl, we must mark it
1820 used now. Otherwise, pass_ipa_free_lang_data won't think it
1822 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1824 this_state
.cur_region
= this_region
;
1827 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1829 return gimple_try_eval (tp
);
1832 /* Implement a cleanup expression. This is similar to try-finally,
1833 except that we only execute the cleanup block for exception edges. */
1836 lower_cleanup (struct leh_state
*state
, gimple tp
)
1838 struct leh_state this_state
= *state
;
1839 eh_region this_region
= NULL
;
1840 struct leh_tf_state fake_tf
;
1842 bool cleanup_dead
= cleanup_is_dead_in (state
->cur_region
);
1844 if (flag_exceptions
&& !cleanup_dead
)
1846 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1847 this_state
.cur_region
= this_region
;
1850 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1852 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1853 return gimple_try_eval (tp
);
1855 /* Build enough of a try-finally state so that we can reuse
1856 honor_protect_cleanup_actions. */
1857 memset (&fake_tf
, 0, sizeof (fake_tf
));
1858 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1859 fake_tf
.outer
= state
;
1860 fake_tf
.region
= this_region
;
1861 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1862 fake_tf
.may_throw
= true;
1864 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1866 if (fake_tf
.may_throw
)
1868 /* In this case honor_protect_cleanup_actions had nothing to do,
1869 and we should process this normally. */
1870 lower_eh_constructs_1 (state
, gimple_try_cleanup (tp
));
1871 result
= frob_into_branch_around (tp
, this_region
,
1872 fake_tf
.fallthru_label
);
1876 /* In this case honor_protect_cleanup_actions did nearly all of
1877 the work. All we have left is to append the fallthru_label. */
1879 result
= gimple_try_eval (tp
);
1880 if (fake_tf
.fallthru_label
)
1882 gimple x
= gimple_build_label (fake_tf
.fallthru_label
);
1883 gimple_seq_add_stmt (&result
, x
);
1889 /* Main loop for lowering eh constructs. Also moves gsi to the next
1893 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1897 gimple stmt
= gsi_stmt (*gsi
);
1899 switch (gimple_code (stmt
))
1903 tree fndecl
= gimple_call_fndecl (stmt
);
1906 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1907 switch (DECL_FUNCTION_CODE (fndecl
))
1909 case BUILT_IN_EH_POINTER
:
1910 /* The front end may have generated a call to
1911 __builtin_eh_pointer (0) within a catch region. Replace
1912 this zero argument with the current catch region number. */
1913 if (state
->ehp_region
)
1915 tree nr
= build_int_cst (integer_type_node
,
1916 state
->ehp_region
->index
);
1917 gimple_call_set_arg (stmt
, 0, nr
);
1921 /* The user has dome something silly. Remove it. */
1922 rhs
= null_pointer_node
;
1927 case BUILT_IN_EH_FILTER
:
1928 /* ??? This should never appear, but since it's a builtin it
1929 is accessible to abuse by users. Just remove it and
1930 replace the use with the arbitrary value zero. */
1931 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
1933 lhs
= gimple_call_lhs (stmt
);
1934 x
= gimple_build_assign (lhs
, rhs
);
1935 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
1938 case BUILT_IN_EH_COPY_VALUES
:
1939 /* Likewise this should not appear. Remove it. */
1940 gsi_remove (gsi
, true);
1950 /* If the stmt can throw use a new temporary for the assignment
1951 to a LHS. This makes sure the old value of the LHS is
1952 available on the EH edge. Only do so for statements that
1953 potentially fall thru (no noreturn calls e.g.), otherwise
1954 this new assignment might create fake fallthru regions. */
1955 if (stmt_could_throw_p (stmt
)
1956 && gimple_has_lhs (stmt
)
1957 && gimple_stmt_may_fallthru (stmt
)
1958 && !tree_could_throw_p (gimple_get_lhs (stmt
))
1959 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
1961 tree lhs
= gimple_get_lhs (stmt
);
1962 tree tmp
= create_tmp_var (TREE_TYPE (lhs
), NULL
);
1963 gimple s
= gimple_build_assign (lhs
, tmp
);
1964 gimple_set_location (s
, gimple_location (stmt
));
1965 gimple_set_block (s
, gimple_block (stmt
));
1966 gimple_set_lhs (stmt
, tmp
);
1967 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
1968 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
1969 DECL_GIMPLE_REG_P (tmp
) = 1;
1970 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
1972 /* Look for things that can throw exceptions, and record them. */
1973 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
1975 record_stmt_eh_region (state
->cur_region
, stmt
);
1976 note_eh_region_may_contain_throw (state
->cur_region
);
1983 maybe_record_in_goto_queue (state
, stmt
);
1987 verify_norecord_switch_expr (state
, stmt
);
1991 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
1992 replace
= lower_try_finally (state
, stmt
);
1995 x
= gimple_seq_first_stmt (gimple_try_cleanup (stmt
));
1998 replace
= gimple_try_eval (stmt
);
1999 lower_eh_constructs_1 (state
, replace
);
2002 switch (gimple_code (x
))
2005 replace
= lower_catch (state
, stmt
);
2007 case GIMPLE_EH_FILTER
:
2008 replace
= lower_eh_filter (state
, stmt
);
2010 case GIMPLE_EH_MUST_NOT_THROW
:
2011 replace
= lower_eh_must_not_throw (state
, stmt
);
2013 case GIMPLE_EH_ELSE
:
2014 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2017 replace
= lower_cleanup (state
, stmt
);
2022 /* Remove the old stmt and insert the transformed sequence
2024 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2025 gsi_remove (gsi
, true);
2027 /* Return since we don't want gsi_next () */
2030 case GIMPLE_EH_ELSE
:
2031 /* We should be eliminating this in lower_try_finally et al. */
2035 /* A type, a decl, or some kind of statement that we're not
2036 interested in. Don't walk them. */
2043 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2046 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq seq
)
2048 gimple_stmt_iterator gsi
;
2049 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
);)
2050 lower_eh_constructs_2 (state
, &gsi
);
2054 lower_eh_constructs (void)
2056 struct leh_state null_state
;
2059 bodyp
= gimple_body (current_function_decl
);
2063 finally_tree
= htab_create (31, struct_ptr_hash
, struct_ptr_eq
, free
);
2064 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2065 memset (&null_state
, 0, sizeof (null_state
));
2067 collect_finally_tree_1 (bodyp
, NULL
);
2068 lower_eh_constructs_1 (&null_state
, bodyp
);
2070 /* We assume there's a return statement, or something, at the end of
2071 the function, and thus ploping the EH sequence afterward won't
2073 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2074 gimple_seq_add_seq (&bodyp
, eh_seq
);
2076 /* We assume that since BODYP already existed, adding EH_SEQ to it
2077 didn't change its value, and we don't have to re-set the function. */
2078 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2080 htab_delete (finally_tree
);
2081 BITMAP_FREE (eh_region_may_contain_throw_map
);
2084 /* If this function needs a language specific EH personality routine
2085 and the frontend didn't already set one do so now. */
2086 if (function_needs_eh_personality (cfun
) == eh_personality_lang
2087 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2088 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2089 = lang_hooks
.eh_personality ();
2094 struct gimple_opt_pass pass_lower_eh
=
2100 lower_eh_constructs
, /* execute */
2103 0, /* static_pass_number */
2104 TV_TREE_EH
, /* tv_id */
2105 PROP_gimple_lcf
, /* properties_required */
2106 PROP_gimple_leh
, /* properties_provided */
2107 0, /* properties_destroyed */
2108 0, /* todo_flags_start */
2109 0 /* todo_flags_finish */
2113 /* Create the multiple edges from an EH_DISPATCH statement to all of
2114 the possible handlers for its EH region. Return true if there's
2115 no fallthru edge; false if there is. */
2118 make_eh_dispatch_edges (gimple stmt
)
2122 basic_block src
, dst
;
2124 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2125 src
= gimple_bb (stmt
);
2130 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2132 dst
= label_to_block (c
->label
);
2133 make_edge (src
, dst
, 0);
2135 /* A catch-all handler doesn't have a fallthru. */
2136 if (c
->type_list
== NULL
)
2141 case ERT_ALLOWED_EXCEPTIONS
:
2142 dst
= label_to_block (r
->u
.allowed
.label
);
2143 make_edge (src
, dst
, 0);
2153 /* Create the single EH edge from STMT to its nearest landing pad,
2154 if there is such a landing pad within the current function. */
2157 make_eh_edges (gimple stmt
)
2159 basic_block src
, dst
;
2163 lp_nr
= lookup_stmt_eh_lp (stmt
);
2167 lp
= get_eh_landing_pad_from_number (lp_nr
);
2168 gcc_assert (lp
!= NULL
);
2170 src
= gimple_bb (stmt
);
2171 dst
= label_to_block (lp
->post_landing_pad
);
2172 make_edge (src
, dst
, EDGE_EH
);
2175 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2176 do not actually perform the final edge redirection.
2178 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2179 we intend to change the destination EH region as well; this means
2180 EH_LANDING_PAD_NR must already be set on the destination block label.
2181 If false, we're being called from generic cfg manipulation code and we
2182 should preserve our place within the region tree. */
2185 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2187 eh_landing_pad old_lp
, new_lp
;
2190 int old_lp_nr
, new_lp_nr
;
2191 tree old_label
, new_label
;
2195 old_bb
= edge_in
->dest
;
2196 old_label
= gimple_block_label (old_bb
);
2197 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2198 gcc_assert (old_lp_nr
> 0);
2199 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2201 throw_stmt
= last_stmt (edge_in
->src
);
2202 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2204 new_label
= gimple_block_label (new_bb
);
2206 /* Look for an existing region that might be using NEW_BB already. */
2207 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2210 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2211 gcc_assert (new_lp
);
2213 /* Unless CHANGE_REGION is true, the new and old landing pad
2214 had better be associated with the same EH region. */
2215 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2220 gcc_assert (!change_region
);
2223 /* Notice when we redirect the last EH edge away from OLD_BB. */
2224 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2225 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2230 /* NEW_LP already exists. If there are still edges into OLD_LP,
2231 there's nothing to do with the EH tree. If there are no more
2232 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2233 If CHANGE_REGION is true, then our caller is expecting to remove
2235 if (e
== NULL
&& !change_region
)
2236 remove_eh_landing_pad (old_lp
);
2240 /* No correct landing pad exists. If there are no more edges
2241 into OLD_LP, then we can simply re-use the existing landing pad.
2242 Otherwise, we have to create a new landing pad. */
2245 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2249 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2250 new_lp
->post_landing_pad
= new_label
;
2251 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2254 /* Maybe move the throwing statement to the new region. */
2255 if (old_lp
!= new_lp
)
2257 remove_stmt_from_eh_lp (throw_stmt
);
2258 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2262 /* Redirect EH edge E to NEW_BB. */
2265 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2267 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2268 return ssa_redirect_edge (edge_in
, new_bb
);
2271 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2272 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2273 The actual edge update will happen in the caller. */
2276 redirect_eh_dispatch_edge (gimple stmt
, edge e
, basic_block new_bb
)
2278 tree new_lab
= gimple_block_label (new_bb
);
2279 bool any_changed
= false;
2284 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2288 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2290 old_bb
= label_to_block (c
->label
);
2291 if (old_bb
== e
->dest
)
2299 case ERT_ALLOWED_EXCEPTIONS
:
2300 old_bb
= label_to_block (r
->u
.allowed
.label
);
2301 gcc_assert (old_bb
== e
->dest
);
2302 r
->u
.allowed
.label
= new_lab
;
2310 gcc_assert (any_changed
);
2313 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2316 operation_could_trap_helper_p (enum tree_code op
,
2327 case TRUNC_DIV_EXPR
:
2329 case FLOOR_DIV_EXPR
:
2330 case ROUND_DIV_EXPR
:
2331 case EXACT_DIV_EXPR
:
2333 case FLOOR_MOD_EXPR
:
2334 case ROUND_MOD_EXPR
:
2335 case TRUNC_MOD_EXPR
:
2337 if (honor_snans
|| honor_trapv
)
2340 return flag_trapping_math
;
2341 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2350 /* Some floating point comparisons may trap. */
2355 case UNORDERED_EXPR
:
2365 case FIX_TRUNC_EXPR
:
2366 /* Conversion of floating point might trap. */
2372 /* These operations don't trap with floating point. */
2380 /* Any floating arithmetic may trap. */
2381 if (fp_operation
&& flag_trapping_math
)
2389 /* Constructing an object cannot trap. */
2393 /* Any floating arithmetic may trap. */
2394 if (fp_operation
&& flag_trapping_math
)
2402 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2403 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2404 type operands that may trap. If OP is a division operator, DIVISOR contains
2405 the value of the divisor. */
2408 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2411 bool honor_nans
= (fp_operation
&& flag_trapping_math
2412 && !flag_finite_math_only
);
2413 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2416 if (TREE_CODE_CLASS (op
) != tcc_comparison
2417 && TREE_CODE_CLASS (op
) != tcc_unary
2418 && TREE_CODE_CLASS (op
) != tcc_binary
)
2421 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2422 honor_nans
, honor_snans
, divisor
,
2426 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2427 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2428 This routine expects only GIMPLE lhs or rhs input. */
2431 tree_could_trap_p (tree expr
)
2433 enum tree_code code
;
2434 bool fp_operation
= false;
2435 bool honor_trapv
= false;
2436 tree t
, base
, div
= NULL_TREE
;
2441 code
= TREE_CODE (expr
);
2442 t
= TREE_TYPE (expr
);
2446 if (COMPARISON_CLASS_P (expr
))
2447 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2449 fp_operation
= FLOAT_TYPE_P (t
);
2450 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2453 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2454 div
= TREE_OPERAND (expr
, 1);
2455 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2461 case TARGET_MEM_REF
:
2462 if (TREE_CODE (TMR_BASE (expr
)) == ADDR_EXPR
2463 && !TMR_INDEX (expr
) && !TMR_INDEX2 (expr
))
2465 return !TREE_THIS_NOTRAP (expr
);
2471 case VIEW_CONVERT_EXPR
:
2472 case WITH_SIZE_EXPR
:
2473 expr
= TREE_OPERAND (expr
, 0);
2474 code
= TREE_CODE (expr
);
2477 case ARRAY_RANGE_REF
:
2478 base
= TREE_OPERAND (expr
, 0);
2479 if (tree_could_trap_p (base
))
2481 if (TREE_THIS_NOTRAP (expr
))
2483 return !range_in_array_bounds_p (expr
);
2486 base
= TREE_OPERAND (expr
, 0);
2487 if (tree_could_trap_p (base
))
2489 if (TREE_THIS_NOTRAP (expr
))
2491 return !in_array_bounds_p (expr
);
2494 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2498 return !TREE_THIS_NOTRAP (expr
);
2501 return TREE_THIS_VOLATILE (expr
);
2504 t
= get_callee_fndecl (expr
);
2505 /* Assume that calls to weak functions may trap. */
2506 if (!t
|| !DECL_P (t
))
2509 return tree_could_trap_p (t
);
2513 /* Assume that accesses to weak functions may trap, unless we know
2514 they are certainly defined in current TU or in some other
2516 if (DECL_WEAK (expr
))
2518 struct cgraph_node
*node
;
2519 if (!DECL_EXTERNAL (expr
))
2521 node
= cgraph_function_node (cgraph_get_node (expr
), NULL
);
2522 if (node
&& node
->in_other_partition
)
2529 /* Assume that accesses to weak vars may trap, unless we know
2530 they are certainly defined in current TU or in some other
2532 if (DECL_WEAK (expr
))
2534 struct varpool_node
*node
;
2535 if (!DECL_EXTERNAL (expr
))
2537 node
= varpool_variable_node (varpool_get_node (expr
), NULL
);
2538 if (node
&& node
->in_other_partition
)
2550 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2551 an assignment or a conditional) may throw. */
2554 stmt_could_throw_1_p (gimple stmt
)
2556 enum tree_code code
= gimple_expr_code (stmt
);
2557 bool honor_nans
= false;
2558 bool honor_snans
= false;
2559 bool fp_operation
= false;
2560 bool honor_trapv
= false;
2565 if (TREE_CODE_CLASS (code
) == tcc_comparison
2566 || TREE_CODE_CLASS (code
) == tcc_unary
2567 || TREE_CODE_CLASS (code
) == tcc_binary
)
2569 if (is_gimple_assign (stmt
)
2570 && TREE_CODE_CLASS (code
) == tcc_comparison
)
2571 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2572 else if (gimple_code (stmt
) == GIMPLE_COND
)
2573 t
= TREE_TYPE (gimple_cond_lhs (stmt
));
2575 t
= gimple_expr_type (stmt
);
2576 fp_operation
= FLOAT_TYPE_P (t
);
2579 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2580 honor_snans
= flag_signaling_nans
!= 0;
2582 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2586 /* Check if the main expression may trap. */
2587 t
= is_gimple_assign (stmt
) ? gimple_assign_rhs2 (stmt
) : NULL
;
2588 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2589 honor_nans
, honor_snans
, t
,
2594 /* If the expression does not trap, see if any of the individual operands may
2596 for (i
= 0; i
< gimple_num_ops (stmt
); i
++)
2597 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2604 /* Return true if statement STMT could throw an exception. */
2607 stmt_could_throw_p (gimple stmt
)
2609 if (!flag_exceptions
)
2612 /* The only statements that can throw an exception are assignments,
2613 conditionals, calls, resx, and asms. */
2614 switch (gimple_code (stmt
))
2620 return !gimple_call_nothrow_p (stmt
);
2624 if (!cfun
->can_throw_non_call_exceptions
)
2626 return stmt_could_throw_1_p (stmt
);
2629 if (!cfun
->can_throw_non_call_exceptions
)
2631 return gimple_asm_volatile_p (stmt
);
2639 /* Return true if expression T could throw an exception. */
2642 tree_could_throw_p (tree t
)
2644 if (!flag_exceptions
)
2646 if (TREE_CODE (t
) == MODIFY_EXPR
)
2648 if (cfun
->can_throw_non_call_exceptions
2649 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2651 t
= TREE_OPERAND (t
, 1);
2654 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2655 t
= TREE_OPERAND (t
, 0);
2656 if (TREE_CODE (t
) == CALL_EXPR
)
2657 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2658 if (cfun
->can_throw_non_call_exceptions
)
2659 return tree_could_trap_p (t
);
2663 /* Return true if STMT can throw an exception that is not caught within
2664 the current function (CFUN). */
2667 stmt_can_throw_external (gimple stmt
)
2671 if (!stmt_could_throw_p (stmt
))
2674 lp_nr
= lookup_stmt_eh_lp (stmt
);
2678 /* Return true if STMT can throw an exception that is caught within
2679 the current function (CFUN). */
2682 stmt_can_throw_internal (gimple stmt
)
2686 if (!stmt_could_throw_p (stmt
))
2689 lp_nr
= lookup_stmt_eh_lp (stmt
);
2693 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2694 remove any entry it might have from the EH table. Return true if
2695 any change was made. */
2698 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple stmt
)
2700 if (stmt_could_throw_p (stmt
))
2702 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2705 /* Likewise, but always use the current function. */
2708 maybe_clean_eh_stmt (gimple stmt
)
2710 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2713 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2714 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2715 in the table if it should be in there. Return TRUE if a replacement was
2716 done that my require an EH edge purge. */
2719 maybe_clean_or_replace_eh_stmt (gimple old_stmt
, gimple new_stmt
)
2721 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2725 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2727 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2730 remove_stmt_from_eh_lp (old_stmt
);
2731 if (new_stmt_could_throw
)
2733 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2743 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statment NEW_STMT
2744 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2745 operand is the return value of duplicate_eh_regions. */
2748 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple new_stmt
,
2749 struct function
*old_fun
, gimple old_stmt
,
2750 struct pointer_map_t
*map
, int default_lp_nr
)
2752 int old_lp_nr
, new_lp_nr
;
2755 if (!stmt_could_throw_p (new_stmt
))
2758 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2761 if (default_lp_nr
== 0)
2763 new_lp_nr
= default_lp_nr
;
2765 else if (old_lp_nr
> 0)
2767 eh_landing_pad old_lp
, new_lp
;
2769 old_lp
= VEC_index (eh_landing_pad
, old_fun
->eh
->lp_array
, old_lp_nr
);
2770 slot
= pointer_map_contains (map
, old_lp
);
2771 new_lp
= (eh_landing_pad
) *slot
;
2772 new_lp_nr
= new_lp
->index
;
2776 eh_region old_r
, new_r
;
2778 old_r
= VEC_index (eh_region
, old_fun
->eh
->region_array
, -old_lp_nr
);
2779 slot
= pointer_map_contains (map
, old_r
);
2780 new_r
= (eh_region
) *slot
;
2781 new_lp_nr
= -new_r
->index
;
2784 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2788 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2789 and thus no remapping is required. */
2792 maybe_duplicate_eh_stmt (gimple new_stmt
, gimple old_stmt
)
2796 if (!stmt_could_throw_p (new_stmt
))
2799 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2803 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2807 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2808 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2809 this only handles handlers consisting of a single call, as that's the
2810 important case for C++: a destructor call for a particular object showing
2811 up in multiple handlers. */
2814 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2816 gimple_stmt_iterator gsi
;
2820 gsi
= gsi_start (oneh
);
2821 if (!gsi_one_before_end_p (gsi
))
2823 ones
= gsi_stmt (gsi
);
2825 gsi
= gsi_start (twoh
);
2826 if (!gsi_one_before_end_p (gsi
))
2828 twos
= gsi_stmt (gsi
);
2830 if (!is_gimple_call (ones
)
2831 || !is_gimple_call (twos
)
2832 || gimple_call_lhs (ones
)
2833 || gimple_call_lhs (twos
)
2834 || gimple_call_chain (ones
)
2835 || gimple_call_chain (twos
)
2836 || !gimple_call_same_target_p (ones
, twos
)
2837 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
2840 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
2841 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
2842 gimple_call_arg (twos
, ai
), 0))
2849 try { A() } finally { try { ~B() } catch { ~A() } }
2850 try { ... } finally { ~A() }
2852 try { A() } catch { ~B() }
2853 try { ~B() ... } finally { ~A() }
2855 This occurs frequently in C++, where A is a local variable and B is a
2856 temporary used in the initializer for A. */
2859 optimize_double_finally (gimple one
, gimple two
)
2862 gimple_stmt_iterator gsi
;
2864 gsi
= gsi_start (gimple_try_cleanup (one
));
2865 if (!gsi_one_before_end_p (gsi
))
2868 oneh
= gsi_stmt (gsi
);
2869 if (gimple_code (oneh
) != GIMPLE_TRY
2870 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
2873 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
2875 gimple_seq seq
= gimple_try_eval (oneh
);
2877 gimple_try_set_cleanup (one
, seq
);
2878 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
2879 seq
= copy_gimple_seq_and_replace_locals (seq
);
2880 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
2881 gimple_try_set_eval (two
, seq
);
2885 /* Perform EH refactoring optimizations that are simpler to do when code
2886 flow has been lowered but EH structures haven't. */
2889 refactor_eh_r (gimple_seq seq
)
2891 gimple_stmt_iterator gsi
;
2896 gsi
= gsi_start (seq
);
2900 if (gsi_end_p (gsi
))
2903 two
= gsi_stmt (gsi
);
2906 && gimple_code (one
) == GIMPLE_TRY
2907 && gimple_code (two
) == GIMPLE_TRY
2908 && gimple_try_kind (one
) == GIMPLE_TRY_FINALLY
2909 && gimple_try_kind (two
) == GIMPLE_TRY_FINALLY
)
2910 optimize_double_finally (one
, two
);
2912 switch (gimple_code (one
))
2915 refactor_eh_r (gimple_try_eval (one
));
2916 refactor_eh_r (gimple_try_cleanup (one
));
2919 refactor_eh_r (gimple_catch_handler (one
));
2921 case GIMPLE_EH_FILTER
:
2922 refactor_eh_r (gimple_eh_filter_failure (one
));
2924 case GIMPLE_EH_ELSE
:
2925 refactor_eh_r (gimple_eh_else_n_body (one
));
2926 refactor_eh_r (gimple_eh_else_e_body (one
));
2941 refactor_eh_r (gimple_body (current_function_decl
));
2946 gate_refactor_eh (void)
2948 return flag_exceptions
!= 0;
2951 struct gimple_opt_pass pass_refactor_eh
=
2956 gate_refactor_eh
, /* gate */
2957 refactor_eh
, /* execute */
2960 0, /* static_pass_number */
2961 TV_TREE_EH
, /* tv_id */
2962 PROP_gimple_lcf
, /* properties_required */
2963 0, /* properties_provided */
2964 0, /* properties_destroyed */
2965 0, /* todo_flags_start */
2966 0 /* todo_flags_finish */
2970 /* At the end of gimple optimization, we can lower RESX. */
2973 lower_resx (basic_block bb
, gimple stmt
, struct pointer_map_t
*mnt_map
)
2976 eh_region src_r
, dst_r
;
2977 gimple_stmt_iterator gsi
;
2982 lp_nr
= lookup_stmt_eh_lp (stmt
);
2984 dst_r
= get_eh_region_from_lp_number (lp_nr
);
2988 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
2989 gsi
= gsi_last_bb (bb
);
2993 /* We can wind up with no source region when pass_cleanup_eh shows
2994 that there are no entries into an eh region and deletes it, but
2995 then the block that contains the resx isn't removed. This can
2996 happen without optimization when the switch statement created by
2997 lower_try_finally_switch isn't simplified to remove the eh case.
2999 Resolve this by expanding the resx node to an abort. */
3001 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3002 x
= gimple_build_call (fn
, 0);
3003 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3005 while (EDGE_COUNT (bb
->succs
) > 0)
3006 remove_edge (EDGE_SUCC (bb
, 0));
3010 /* When we have a destination region, we resolve this by copying
3011 the excptr and filter values into place, and changing the edge
3012 to immediately after the landing pad. */
3021 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3022 the failure decl into a new block, if needed. */
3023 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3025 slot
= pointer_map_contains (mnt_map
, dst_r
);
3028 gimple_stmt_iterator gsi2
;
3030 new_bb
= create_empty_bb (bb
);
3031 lab
= gimple_block_label (new_bb
);
3032 gsi2
= gsi_start_bb (new_bb
);
3034 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3035 x
= gimple_build_call (fn
, 0);
3036 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3037 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3039 slot
= pointer_map_insert (mnt_map
, dst_r
);
3045 new_bb
= label_to_block (lab
);
3048 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3049 e
= make_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3050 e
->count
= bb
->count
;
3051 e
->probability
= REG_BR_PROB_BASE
;
3056 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3058 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3059 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3060 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3061 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3063 /* Update the flags for the outgoing edge. */
3064 e
= single_succ_edge (bb
);
3065 gcc_assert (e
->flags
& EDGE_EH
);
3066 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3068 /* If there are no more EH users of the landing pad, delete it. */
3069 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3070 if (e
->flags
& EDGE_EH
)
3074 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3075 remove_eh_landing_pad (lp
);
3085 /* When we don't have a destination region, this exception escapes
3086 up the call chain. We resolve this by generating a call to the
3087 _Unwind_Resume library function. */
3089 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3090 with no arguments for C++ and Java. Check for that. */
3091 if (src_r
->use_cxa_end_cleanup
)
3093 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3094 x
= gimple_build_call (fn
, 0);
3095 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3099 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3100 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3101 x
= gimple_build_call (fn
, 1, src_nr
);
3102 var
= create_tmp_var (ptr_type_node
, NULL
);
3103 var
= make_ssa_name (var
, x
);
3104 gimple_call_set_lhs (x
, var
);
3105 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3107 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3108 x
= gimple_build_call (fn
, 1, var
);
3109 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3112 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3115 gsi_remove (&gsi
, true);
3121 execute_lower_resx (void)
3124 struct pointer_map_t
*mnt_map
;
3125 bool dominance_invalidated
= false;
3126 bool any_rewritten
= false;
3128 mnt_map
= pointer_map_create ();
3132 gimple last
= last_stmt (bb
);
3133 if (last
&& is_gimple_resx (last
))
3135 dominance_invalidated
|= lower_resx (bb
, last
, mnt_map
);
3136 any_rewritten
= true;
3140 pointer_map_destroy (mnt_map
);
3142 if (dominance_invalidated
)
3144 free_dominance_info (CDI_DOMINATORS
);
3145 free_dominance_info (CDI_POST_DOMINATORS
);
3148 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3152 gate_lower_resx (void)
3154 return flag_exceptions
!= 0;
3157 struct gimple_opt_pass pass_lower_resx
=
3162 gate_lower_resx
, /* gate */
3163 execute_lower_resx
, /* execute */
3166 0, /* static_pass_number */
3167 TV_TREE_EH
, /* tv_id */
3168 PROP_gimple_lcf
, /* properties_required */
3169 0, /* properties_provided */
3170 0, /* properties_destroyed */
3171 0, /* todo_flags_start */
3172 TODO_verify_flow
/* todo_flags_finish */
3177 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3178 we have found some duplicate labels and removed some edges. */
3181 lower_eh_dispatch (basic_block src
, gimple stmt
)
3183 gimple_stmt_iterator gsi
;
3188 bool redirected
= false;
3190 region_nr
= gimple_eh_dispatch_region (stmt
);
3191 r
= get_eh_region_from_number (region_nr
);
3193 gsi
= gsi_last_bb (src
);
3199 VEC (tree
, heap
) *labels
= NULL
;
3200 tree default_label
= NULL
;
3204 struct pointer_set_t
*seen_values
= pointer_set_create ();
3206 /* Collect the labels for a switch. Zero the post_landing_pad
3207 field becase we'll no longer have anything keeping these labels
3208 in existance and the optimizer will be free to merge these
3210 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3212 tree tp_node
, flt_node
, lab
= c
->label
;
3213 bool have_label
= false;
3216 tp_node
= c
->type_list
;
3217 flt_node
= c
->filter_list
;
3219 if (tp_node
== NULL
)
3221 default_label
= lab
;
3226 /* Filter out duplicate labels that arise when this handler
3227 is shadowed by an earlier one. When no labels are
3228 attached to the handler anymore, we remove
3229 the corresponding edge and then we delete unreachable
3230 blocks at the end of this pass. */
3231 if (! pointer_set_contains (seen_values
, TREE_VALUE (flt_node
)))
3233 tree t
= build_case_label (TREE_VALUE (flt_node
),
3235 VEC_safe_push (tree
, heap
, labels
, t
);
3236 pointer_set_insert (seen_values
, TREE_VALUE (flt_node
));
3240 tp_node
= TREE_CHAIN (tp_node
);
3241 flt_node
= TREE_CHAIN (flt_node
);
3246 remove_edge (find_edge (src
, label_to_block (lab
)));
3251 /* Clean up the edge flags. */
3252 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3254 if (e
->flags
& EDGE_FALLTHRU
)
3256 /* If there was no catch-all, use the fallthru edge. */
3257 if (default_label
== NULL
)
3258 default_label
= gimple_block_label (e
->dest
);
3259 e
->flags
&= ~EDGE_FALLTHRU
;
3262 gcc_assert (default_label
!= NULL
);
3264 /* Don't generate a switch if there's only a default case.
3265 This is common in the form of try { A; } catch (...) { B; }. */
3268 e
= single_succ_edge (src
);
3269 e
->flags
|= EDGE_FALLTHRU
;
3273 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3274 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3276 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3277 filter
= make_ssa_name (filter
, x
);
3278 gimple_call_set_lhs (x
, filter
);
3279 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3281 /* Turn the default label into a default case. */
3282 default_label
= build_case_label (NULL
, NULL
, default_label
);
3283 sort_case_labels (labels
);
3285 x
= gimple_build_switch_vec (filter
, default_label
, labels
);
3286 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3288 VEC_free (tree
, heap
, labels
);
3290 pointer_set_destroy (seen_values
);
3294 case ERT_ALLOWED_EXCEPTIONS
:
3296 edge b_e
= BRANCH_EDGE (src
);
3297 edge f_e
= FALLTHRU_EDGE (src
);
3299 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3300 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3302 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3303 filter
= make_ssa_name (filter
, x
);
3304 gimple_call_set_lhs (x
, filter
);
3305 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3307 r
->u
.allowed
.label
= NULL
;
3308 x
= gimple_build_cond (EQ_EXPR
, filter
,
3309 build_int_cst (TREE_TYPE (filter
),
3310 r
->u
.allowed
.filter
),
3311 NULL_TREE
, NULL_TREE
);
3312 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3314 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3315 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3323 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3324 gsi_remove (&gsi
, true);
3329 execute_lower_eh_dispatch (void)
3332 bool any_rewritten
= false;
3333 bool redirected
= false;
3335 assign_filter_values ();
3339 gimple last
= last_stmt (bb
);
3340 if (last
&& gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3342 redirected
|= lower_eh_dispatch (bb
, last
);
3343 any_rewritten
= true;
3348 delete_unreachable_blocks ();
3349 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3353 gate_lower_eh_dispatch (void)
3355 return cfun
->eh
->region_tree
!= NULL
;
3358 struct gimple_opt_pass pass_lower_eh_dispatch
=
3362 "ehdisp", /* name */
3363 gate_lower_eh_dispatch
, /* gate */
3364 execute_lower_eh_dispatch
, /* execute */
3367 0, /* static_pass_number */
3368 TV_TREE_EH
, /* tv_id */
3369 PROP_gimple_lcf
, /* properties_required */
3370 0, /* properties_provided */
3371 0, /* properties_destroyed */
3372 0, /* todo_flags_start */
3373 TODO_verify_flow
/* todo_flags_finish */
3377 /* Walk statements, see what regions are really referenced and remove
3378 those that are unused. */
3381 remove_unreachable_handlers (void)
3383 sbitmap r_reachable
, lp_reachable
;
3389 r_reachable
= sbitmap_alloc (VEC_length (eh_region
, cfun
->eh
->region_array
));
3391 = sbitmap_alloc (VEC_length (eh_landing_pad
, cfun
->eh
->lp_array
));
3392 sbitmap_zero (r_reachable
);
3393 sbitmap_zero (lp_reachable
);
3397 gimple_stmt_iterator gsi
;
3399 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3401 gimple stmt
= gsi_stmt (gsi
);
3402 lp_nr
= lookup_stmt_eh_lp (stmt
);
3404 /* Negative LP numbers are MUST_NOT_THROW regions which
3405 are not considered BB enders. */
3407 SET_BIT (r_reachable
, -lp_nr
);
3409 /* Positive LP numbers are real landing pads, are are BB enders. */
3412 gcc_assert (gsi_one_before_end_p (gsi
));
3413 region
= get_eh_region_from_lp_number (lp_nr
);
3414 SET_BIT (r_reachable
, region
->index
);
3415 SET_BIT (lp_reachable
, lp_nr
);
3418 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3419 switch (gimple_code (stmt
))
3422 SET_BIT (r_reachable
, gimple_resx_region (stmt
));
3424 case GIMPLE_EH_DISPATCH
:
3425 SET_BIT (r_reachable
, gimple_eh_dispatch_region (stmt
));
3435 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3436 dump_eh_tree (dump_file
, cfun
);
3437 fprintf (dump_file
, "Reachable regions: ");
3438 dump_sbitmap_file (dump_file
, r_reachable
);
3439 fprintf (dump_file
, "Reachable landing pads: ");
3440 dump_sbitmap_file (dump_file
, lp_reachable
);
3444 VEC_iterate (eh_region
, cfun
->eh
->region_array
, r_nr
, region
); ++r_nr
)
3445 if (region
&& !TEST_BIT (r_reachable
, r_nr
))
3448 fprintf (dump_file
, "Removing unreachable region %d\n", r_nr
);
3449 remove_eh_handler (region
);
3453 VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, lp_nr
, lp
); ++lp_nr
)
3454 if (lp
&& !TEST_BIT (lp_reachable
, lp_nr
))
3457 fprintf (dump_file
, "Removing unreachable landing pad %d\n", lp_nr
);
3458 remove_eh_landing_pad (lp
);
3463 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3464 dump_eh_tree (dump_file
, cfun
);
3465 fprintf (dump_file
, "\n\n");
3468 sbitmap_free (r_reachable
);
3469 sbitmap_free (lp_reachable
);
3471 #ifdef ENABLE_CHECKING
3472 verify_eh_tree (cfun
);
3476 /* Remove unreachable handlers if any landing pads have been removed after
3477 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3480 maybe_remove_unreachable_handlers (void)
3485 if (cfun
->eh
== NULL
)
3488 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3489 if (lp
&& lp
->post_landing_pad
)
3491 if (label_to_block (lp
->post_landing_pad
) == NULL
)
3493 remove_unreachable_handlers ();
3499 /* Remove regions that do not have landing pads. This assumes
3500 that remove_unreachable_handlers has already been run, and
3501 that we've just manipulated the landing pads since then. */
3504 remove_unreachable_handlers_no_lp (void)
3509 for (i
= 1; VEC_iterate (eh_region
, cfun
->eh
->region_array
, i
, r
); ++i
)
3510 if (r
&& r
->landing_pads
== NULL
&& r
->type
!= ERT_MUST_NOT_THROW
)
3513 fprintf (dump_file
, "Removing unreachable region %d\n", i
);
3514 remove_eh_handler (r
);
3518 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3519 optimisticaly split all sorts of edges, including EH edges. The
3520 optimization passes in between may not have needed them; if not,
3521 we should undo the split.
3523 Recognize this case by having one EH edge incoming to the BB and
3524 one normal edge outgoing; BB should be empty apart from the
3525 post_landing_pad label.
3527 Note that this is slightly different from the empty handler case
3528 handled by cleanup_empty_eh, in that the actual handler may yet
3529 have actual code but the landing pad has been separated from the
3530 handler. As such, cleanup_empty_eh relies on this transformation
3531 having been done first. */
3534 unsplit_eh (eh_landing_pad lp
)
3536 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3537 gimple_stmt_iterator gsi
;
3540 /* Quickly check the edge counts on BB for singularity. */
3541 if (EDGE_COUNT (bb
->preds
) != 1 || EDGE_COUNT (bb
->succs
) != 1)
3543 e_in
= EDGE_PRED (bb
, 0);
3544 e_out
= EDGE_SUCC (bb
, 0);
3546 /* Input edge must be EH and output edge must be normal. */
3547 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
3550 /* The block must be empty except for the labels and debug insns. */
3551 gsi
= gsi_after_labels (bb
);
3552 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3553 gsi_next_nondebug (&gsi
);
3554 if (!gsi_end_p (gsi
))
3557 /* The destination block must not already have a landing pad
3558 for a different region. */
3559 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3561 gimple stmt
= gsi_stmt (gsi
);
3565 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3567 lab
= gimple_label_label (stmt
);
3568 lp_nr
= EH_LANDING_PAD_NR (lab
);
3569 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3573 /* The new destination block must not already be a destination of
3574 the source block, lest we merge fallthru and eh edges and get
3575 all sorts of confused. */
3576 if (find_edge (e_in
->src
, e_out
->dest
))
3579 /* ??? We can get degenerate phis due to cfg cleanups. I would have
3580 thought this should have been cleaned up by a phicprop pass, but
3581 that doesn't appear to handle virtuals. Propagate by hand. */
3582 if (!gimple_seq_empty_p (phi_nodes (bb
)))
3584 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); )
3586 gimple use_stmt
, phi
= gsi_stmt (gsi
);
3587 tree lhs
= gimple_phi_result (phi
);
3588 tree rhs
= gimple_phi_arg_def (phi
, 0);
3589 use_operand_p use_p
;
3590 imm_use_iterator iter
;
3592 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
3594 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3595 SET_USE (use_p
, rhs
);
3598 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
3599 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
3601 remove_phi_node (&gsi
, true);
3605 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3606 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
3607 lp
->index
, e_out
->dest
->index
);
3609 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
3610 a successor edge, humor it. But do the real CFG change with the
3611 predecessor of E_OUT in order to preserve the ordering of arguments
3612 to the PHI nodes in E_OUT->DEST. */
3613 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
3614 redirect_edge_pred (e_out
, e_in
->src
);
3615 e_out
->flags
= e_in
->flags
;
3616 e_out
->probability
= e_in
->probability
;
3617 e_out
->count
= e_in
->count
;
3623 /* Examine each landing pad block and see if it matches unsplit_eh. */
3626 unsplit_all_eh (void)
3628 bool changed
= false;
3632 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3634 changed
|= unsplit_eh (lp
);
3639 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
3640 to OLD_BB to NEW_BB; return true on success, false on failure.
3642 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
3643 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
3644 Virtual PHIs may be deleted and marked for renaming. */
3647 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
3648 edge old_bb_out
, bool change_region
)
3650 gimple_stmt_iterator ngsi
, ogsi
;
3653 bitmap rename_virts
;
3654 bitmap ophi_handled
;
3656 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3657 redirect_edge_var_map_clear (e
);
3659 ophi_handled
= BITMAP_ALLOC (NULL
);
3660 rename_virts
= BITMAP_ALLOC (NULL
);
3662 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
3663 for the edges we're going to move. */
3664 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
3666 gimple ophi
, nphi
= gsi_stmt (ngsi
);
3669 nresult
= gimple_phi_result (nphi
);
3670 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
3672 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
3673 the source ssa_name. */
3675 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3677 ophi
= gsi_stmt (ogsi
);
3678 if (gimple_phi_result (ophi
) == nop
)
3683 /* If we did find the corresponding PHI, copy those inputs. */
3686 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
3687 if (!has_single_use (nop
))
3689 imm_use_iterator imm_iter
;
3690 use_operand_p use_p
;
3692 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
3694 if (!gimple_debug_bind_p (USE_STMT (use_p
))
3695 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
3696 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
3700 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
3701 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3706 if ((e
->flags
& EDGE_EH
) == 0)
3708 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
3709 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
3710 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
3713 /* If we didn't find the PHI, but it's a VOP, remember to rename
3714 it later, assuming all other tests succeed. */
3715 else if (!is_gimple_reg (nresult
))
3716 bitmap_set_bit (rename_virts
, SSA_NAME_VERSION (nresult
));
3717 /* If we didn't find the PHI, and it's a real variable, we know
3718 from the fact that OLD_BB is tree_empty_eh_handler_p that the
3719 variable is unchanged from input to the block and we can simply
3720 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
3724 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
3725 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3726 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
3730 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
3731 we don't know what values from the other edges into NEW_BB to use. */
3732 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3734 gimple ophi
= gsi_stmt (ogsi
);
3735 tree oresult
= gimple_phi_result (ophi
);
3736 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
3740 /* At this point we know that the merge will succeed. Remove the PHI
3741 nodes for the virtuals that we want to rename. */
3742 if (!bitmap_empty_p (rename_virts
))
3744 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); )
3746 gimple nphi
= gsi_stmt (ngsi
);
3747 tree nresult
= gimple_phi_result (nphi
);
3748 if (bitmap_bit_p (rename_virts
, SSA_NAME_VERSION (nresult
)))
3750 mark_virtual_phi_result_for_renaming (nphi
);
3751 remove_phi_node (&ngsi
, true);
3758 /* Finally, move the edges and update the PHIs. */
3759 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
3760 if (e
->flags
& EDGE_EH
)
3762 redirect_eh_edge_1 (e
, new_bb
, change_region
);
3763 redirect_edge_succ (e
, new_bb
);
3764 flush_pending_stmts (e
);
3769 BITMAP_FREE (ophi_handled
);
3770 BITMAP_FREE (rename_virts
);
3774 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3775 redirect_edge_var_map_clear (e
);
3776 BITMAP_FREE (ophi_handled
);
3777 BITMAP_FREE (rename_virts
);
3781 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
3782 old region to NEW_REGION at BB. */
3785 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
3786 eh_landing_pad lp
, eh_region new_region
)
3788 gimple_stmt_iterator gsi
;
3791 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
3795 lp
->region
= new_region
;
3796 lp
->next_lp
= new_region
->landing_pads
;
3797 new_region
->landing_pads
= lp
;
3799 /* Delete the RESX that was matched within the empty handler block. */
3800 gsi
= gsi_last_bb (bb
);
3801 mark_virtual_ops_for_renaming (gsi_stmt (gsi
));
3802 gsi_remove (&gsi
, true);
3804 /* Clean up E_OUT for the fallthru. */
3805 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3806 e_out
->probability
= REG_BR_PROB_BASE
;
3809 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
3810 unsplitting than unsplit_eh was prepared to handle, e.g. when
3811 multiple incoming edges and phis are involved. */
3814 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
3816 gimple_stmt_iterator gsi
;
3821 /* We really ought not have totally lost everything following
3822 a landing pad label. Given that BB is empty, there had better
3824 gcc_assert (e_out
!= NULL
);
3826 /* The destination block must not already have a landing pad
3827 for a different region. */
3829 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3831 gimple stmt
= gsi_stmt (gsi
);
3834 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3836 lab
= gimple_label_label (stmt
);
3837 lp_nr
= EH_LANDING_PAD_NR (lab
);
3838 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3842 /* The destination block must not be a regular successor for any
3843 of the preds of the landing pad. Thus, avoid turning
3853 which CFG verification would choke on. See PR45172. */
3854 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3855 if (find_edge (e
->src
, e_out
->dest
))
3858 /* Attempt to move the PHIs into the successor block. */
3859 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
3861 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3863 "Unsplit EH landing pad %d to block %i "
3864 "(via cleanup_empty_eh).\n",
3865 lp
->index
, e_out
->dest
->index
);
3872 /* Return true if edge E_FIRST is part of an empty infinite loop
3873 or leads to such a loop through a series of single successor
3877 infinite_empty_loop_p (edge e_first
)
3879 bool inf_loop
= false;
3882 if (e_first
->dest
== e_first
->src
)
3885 e_first
->src
->aux
= (void *) 1;
3886 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
3888 gimple_stmt_iterator gsi
;
3894 e
->dest
->aux
= (void *) 1;
3895 gsi
= gsi_after_labels (e
->dest
);
3896 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3897 gsi_next_nondebug (&gsi
);
3898 if (!gsi_end_p (gsi
))
3901 e_first
->src
->aux
= NULL
;
3902 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
3903 e
->dest
->aux
= NULL
;
3908 /* Examine the block associated with LP to determine if it's an empty
3909 handler for its EH region. If so, attempt to redirect EH edges to
3910 an outer region. Return true the CFG was updated in any way. This
3911 is similar to jump forwarding, just across EH edges. */
3914 cleanup_empty_eh (eh_landing_pad lp
)
3916 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3917 gimple_stmt_iterator gsi
;
3919 eh_region new_region
;
3922 bool has_non_eh_pred
;
3925 /* There can be zero or one edges out of BB. This is the quickest test. */
3926 switch (EDGE_COUNT (bb
->succs
))
3932 e_out
= EDGE_SUCC (bb
, 0);
3937 gsi
= gsi_after_labels (bb
);
3939 /* Make sure to skip debug statements. */
3940 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3941 gsi_next_nondebug (&gsi
);
3943 /* If the block is totally empty, look for more unsplitting cases. */
3944 if (gsi_end_p (gsi
))
3946 /* For the degenerate case of an infinite loop bail out. */
3947 if (infinite_empty_loop_p (e_out
))
3950 return cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
3953 /* The block should consist only of a single RESX statement, modulo a
3954 preceding call to __builtin_stack_restore if there is no outgoing
3955 edge, since the call can be eliminated in this case. */
3956 resx
= gsi_stmt (gsi
);
3957 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
3960 resx
= gsi_stmt (gsi
);
3962 if (!is_gimple_resx (resx
))
3964 gcc_assert (gsi_one_before_end_p (gsi
));
3966 /* Determine if there are non-EH edges, or resx edges into the handler. */
3967 has_non_eh_pred
= false;
3968 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3969 if (!(e
->flags
& EDGE_EH
))
3970 has_non_eh_pred
= true;
3972 /* Find the handler that's outer of the empty handler by looking at
3973 where the RESX instruction was vectored. */
3974 new_lp_nr
= lookup_stmt_eh_lp (resx
);
3975 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
3977 /* If there's no destination region within the current function,
3978 redirection is trivial via removing the throwing statements from
3979 the EH region, removing the EH edges, and allowing the block
3980 to go unreachable. */
3981 if (new_region
== NULL
)
3983 gcc_assert (e_out
== NULL
);
3984 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
3985 if (e
->flags
& EDGE_EH
)
3987 gimple stmt
= last_stmt (e
->src
);
3988 remove_stmt_from_eh_lp (stmt
);
3996 /* If the destination region is a MUST_NOT_THROW, allow the runtime
3997 to handle the abort and allow the blocks to go unreachable. */
3998 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4000 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4001 if (e
->flags
& EDGE_EH
)
4003 gimple stmt
= last_stmt (e
->src
);
4004 remove_stmt_from_eh_lp (stmt
);
4005 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4013 /* Try to redirect the EH edges and merge the PHIs into the destination
4014 landing pad block. If the merge succeeds, we'll already have redirected
4015 all the EH edges. The handler itself will go unreachable if there were
4017 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4020 /* Finally, if all input edges are EH edges, then we can (potentially)
4021 reduce the number of transfers from the runtime by moving the landing
4022 pad from the original region to the new region. This is a win when
4023 we remove the last CLEANUP region along a particular exception
4024 propagation path. Since nothing changes except for the region with
4025 which the landing pad is associated, the PHI nodes do not need to be
4027 if (!has_non_eh_pred
)
4029 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4030 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4031 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4032 lp
->index
, new_region
->index
);
4034 /* ??? The CFG didn't change, but we may have rendered the
4035 old EH region unreachable. Trigger a cleanup there. */
4042 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4043 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4044 remove_eh_landing_pad (lp
);
4048 /* Do a post-order traversal of the EH region tree. Examine each
4049 post_landing_pad block and see if we can eliminate it as empty. */
4052 cleanup_all_empty_eh (void)
4054 bool changed
= false;
4058 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
4060 changed
|= cleanup_empty_eh (lp
);
4065 /* Perform cleanups and lowering of exception handling
4066 1) cleanups regions with handlers doing nothing are optimized out
4067 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4068 3) Info about regions that are containing instructions, and regions
4069 reachable via local EH edges is collected
4070 4) Eh tree is pruned for regions no longer neccesary.
4072 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4073 Unify those that have the same failure decl and locus.
4077 execute_cleanup_eh_1 (void)
4079 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4080 looking up unreachable landing pads. */
4081 remove_unreachable_handlers ();
4083 /* Watch out for the region tree vanishing due to all unreachable. */
4084 if (cfun
->eh
->region_tree
&& optimize
)
4086 bool changed
= false;
4088 changed
|= unsplit_all_eh ();
4089 changed
|= cleanup_all_empty_eh ();
4093 free_dominance_info (CDI_DOMINATORS
);
4094 free_dominance_info (CDI_POST_DOMINATORS
);
4096 /* We delayed all basic block deletion, as we may have performed
4097 cleanups on EH edges while non-EH edges were still present. */
4098 delete_unreachable_blocks ();
4100 /* We manipulated the landing pads. Remove any region that no
4101 longer has a landing pad. */
4102 remove_unreachable_handlers_no_lp ();
4104 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4112 execute_cleanup_eh (void)
4114 int ret
= execute_cleanup_eh_1 ();
4116 /* If the function no longer needs an EH personality routine
4117 clear it. This exposes cross-language inlining opportunities
4118 and avoids references to a never defined personality routine. */
4119 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4120 && function_needs_eh_personality (cfun
) != eh_personality_lang
)
4121 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4127 gate_cleanup_eh (void)
4129 return cfun
->eh
!= NULL
&& cfun
->eh
->region_tree
!= NULL
;
4132 struct gimple_opt_pass pass_cleanup_eh
= {
4135 "ehcleanup", /* name */
4136 gate_cleanup_eh
, /* gate */
4137 execute_cleanup_eh
, /* execute */
4140 0, /* static_pass_number */
4141 TV_TREE_EH
, /* tv_id */
4142 PROP_gimple_lcf
, /* properties_required */
4143 0, /* properties_provided */
4144 0, /* properties_destroyed */
4145 0, /* todo_flags_start */
4146 0 /* todo_flags_finish */
4150 /* Verify that BB containing STMT as the last statement, has precisely the
4151 edge that make_eh_edges would create. */
4154 verify_eh_edges (gimple stmt
)
4156 basic_block bb
= gimple_bb (stmt
);
4157 eh_landing_pad lp
= NULL
;
4162 lp_nr
= lookup_stmt_eh_lp (stmt
);
4164 lp
= get_eh_landing_pad_from_number (lp_nr
);
4167 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4169 if (e
->flags
& EDGE_EH
)
4173 error ("BB %i has multiple EH edges", bb
->index
);
4185 error ("BB %i can not throw but has an EH edge", bb
->index
);
4191 if (!stmt_could_throw_p (stmt
))
4193 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4197 if (eh_edge
== NULL
)
4199 error ("BB %i is missing an EH edge", bb
->index
);
4203 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
4205 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4212 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4215 verify_eh_dispatch_edge (gimple stmt
)
4219 basic_block src
, dst
;
4220 bool want_fallthru
= true;
4224 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4225 src
= gimple_bb (stmt
);
4227 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4228 gcc_assert (e
->aux
== NULL
);
4233 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4235 dst
= label_to_block (c
->label
);
4236 e
= find_edge (src
, dst
);
4239 error ("BB %i is missing an edge", src
->index
);
4244 /* A catch-all handler doesn't have a fallthru. */
4245 if (c
->type_list
== NULL
)
4247 want_fallthru
= false;
4253 case ERT_ALLOWED_EXCEPTIONS
:
4254 dst
= label_to_block (r
->u
.allowed
.label
);
4255 e
= find_edge (src
, dst
);
4258 error ("BB %i is missing an edge", src
->index
);
4269 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4271 if (e
->flags
& EDGE_FALLTHRU
)
4273 if (fall_edge
!= NULL
)
4275 error ("BB %i too many fallthru edges", src
->index
);
4284 error ("BB %i has incorrect edge", src
->index
);
4288 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4290 error ("BB %i has incorrect fallthru edge", src
->index
);