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
);
1542 gimple_stmt_iterator gsi
;
1547 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1549 gimple stmt
= gsi_stmt (gsi
);
1550 if (!is_gimple_debug (stmt
) && !gimple_clobber_p (stmt
))
1556 /* Finally estimate N times, plus N gotos. */
1557 f_estimate
= count_insns_seq (finally
, &eni_size_weights
);
1558 f_estimate
= (f_estimate
+ 1) * ndests
;
1560 /* Switch statement (cost 10), N variable assignments, N gotos. */
1561 sw_estimate
= 10 + 2 * ndests
;
1563 /* Optimize for size clearly wants our best guess. */
1564 if (optimize_function_for_size_p (cfun
))
1565 return f_estimate
< sw_estimate
;
1567 /* ??? These numbers are completely made up so far. */
1569 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1571 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1574 /* REG is the enclosing region for a possible cleanup region, or the region
1575 itself. Returns TRUE if such a region would be unreachable.
1577 Cleanup regions within a must-not-throw region aren't actually reachable
1578 even if there are throwing stmts within them, because the personality
1579 routine will call terminate before unwinding. */
1582 cleanup_is_dead_in (eh_region reg
)
1584 while (reg
&& reg
->type
== ERT_CLEANUP
)
1586 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1589 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1590 to a sequence of labels and blocks, plus the exception region trees
1591 that record all the magic. This is complicated by the need to
1592 arrange for the FINALLY block to be executed on all exits. */
1595 lower_try_finally (struct leh_state
*state
, gimple tp
)
1597 struct leh_tf_state this_tf
;
1598 struct leh_state this_state
;
1600 gimple_seq old_eh_seq
;
1602 /* Process the try block. */
1604 memset (&this_tf
, 0, sizeof (this_tf
));
1605 this_tf
.try_finally_expr
= tp
;
1607 this_tf
.outer
= state
;
1608 if (using_eh_for_cleanups_p
&& !cleanup_is_dead_in (state
->cur_region
))
1610 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1611 this_state
.cur_region
= this_tf
.region
;
1615 this_tf
.region
= NULL
;
1616 this_state
.cur_region
= state
->cur_region
;
1619 this_state
.ehp_region
= state
->ehp_region
;
1620 this_state
.tf
= &this_tf
;
1622 old_eh_seq
= eh_seq
;
1625 lower_eh_constructs_1 (&this_state
, gimple_try_eval(tp
));
1627 /* Determine if the try block is escaped through the bottom. */
1628 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1630 /* Determine if any exceptions are possible within the try block. */
1632 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1633 if (this_tf
.may_throw
)
1634 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1636 /* Determine how many edges (still) reach the finally block. Or rather,
1637 how many destinations are reached by the finally block. Use this to
1638 determine how we process the finally block itself. */
1640 ndests
= VEC_length (tree
, this_tf
.dest_array
);
1641 ndests
+= this_tf
.may_fallthru
;
1642 ndests
+= this_tf
.may_return
;
1643 ndests
+= this_tf
.may_throw
;
1645 /* If the FINALLY block is not reachable, dike it out. */
1648 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1649 gimple_try_set_cleanup (tp
, NULL
);
1651 /* If the finally block doesn't fall through, then any destination
1652 we might try to impose there isn't reached either. There may be
1653 some minor amount of cleanup and redirection still needed. */
1654 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1655 lower_try_finally_nofallthru (state
, &this_tf
);
1657 /* We can easily special-case redirection to a single destination. */
1658 else if (ndests
== 1)
1659 lower_try_finally_onedest (state
, &this_tf
);
1660 else if (decide_copy_try_finally (ndests
, this_tf
.may_throw
,
1661 gimple_try_cleanup (tp
)))
1662 lower_try_finally_copy (state
, &this_tf
);
1664 lower_try_finally_switch (state
, &this_tf
);
1666 /* If someone requested we add a label at the end of the transformed
1668 if (this_tf
.fallthru_label
)
1670 /* This must be reached only if ndests == 0. */
1671 gimple x
= gimple_build_label (this_tf
.fallthru_label
);
1672 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1675 VEC_free (tree
, heap
, this_tf
.dest_array
);
1676 free (this_tf
.goto_queue
);
1677 if (this_tf
.goto_queue_map
)
1678 pointer_map_destroy (this_tf
.goto_queue_map
);
1680 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1681 If there was no old eh_seq, then the append is trivially already done. */
1685 eh_seq
= old_eh_seq
;
1688 gimple_seq new_eh_seq
= eh_seq
;
1689 eh_seq
= old_eh_seq
;
1690 gimple_seq_add_seq(&eh_seq
, new_eh_seq
);
1694 return this_tf
.top_p_seq
;
1697 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1698 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1699 exception region trees that records all the magic. */
1702 lower_catch (struct leh_state
*state
, gimple tp
)
1704 eh_region try_region
= NULL
;
1705 struct leh_state this_state
= *state
;
1706 gimple_stmt_iterator gsi
;
1710 location_t try_catch_loc
= gimple_location (tp
);
1712 if (flag_exceptions
)
1714 try_region
= gen_eh_region_try (state
->cur_region
);
1715 this_state
.cur_region
= try_region
;
1718 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1720 if (!eh_region_may_contain_throw (try_region
))
1721 return gimple_try_eval (tp
);
1724 emit_eh_dispatch (&new_seq
, try_region
);
1725 emit_resx (&new_seq
, try_region
);
1727 this_state
.cur_region
= state
->cur_region
;
1728 this_state
.ehp_region
= try_region
;
1731 for (gsi
= gsi_start (gimple_try_cleanup (tp
));
1739 gcatch
= gsi_stmt (gsi
);
1740 c
= gen_eh_region_catch (try_region
, gimple_catch_types (gcatch
));
1742 handler
= gimple_catch_handler (gcatch
);
1743 lower_eh_constructs_1 (&this_state
, handler
);
1745 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1746 x
= gimple_build_label (c
->label
);
1747 gimple_seq_add_stmt (&new_seq
, x
);
1749 gimple_seq_add_seq (&new_seq
, handler
);
1751 if (gimple_seq_may_fallthru (new_seq
))
1754 out_label
= create_artificial_label (try_catch_loc
);
1756 x
= gimple_build_goto (out_label
);
1757 gimple_seq_add_stmt (&new_seq
, x
);
1763 gimple_try_set_cleanup (tp
, new_seq
);
1765 return frob_into_branch_around (tp
, try_region
, out_label
);
1768 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1769 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1770 region trees that record all the magic. */
1773 lower_eh_filter (struct leh_state
*state
, gimple tp
)
1775 struct leh_state this_state
= *state
;
1776 eh_region this_region
= NULL
;
1780 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1782 if (flag_exceptions
)
1784 this_region
= gen_eh_region_allowed (state
->cur_region
,
1785 gimple_eh_filter_types (inner
));
1786 this_state
.cur_region
= this_region
;
1789 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1791 if (!eh_region_may_contain_throw (this_region
))
1792 return gimple_try_eval (tp
);
1795 this_state
.cur_region
= state
->cur_region
;
1796 this_state
.ehp_region
= this_region
;
1798 emit_eh_dispatch (&new_seq
, this_region
);
1799 emit_resx (&new_seq
, this_region
);
1801 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1802 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1803 gimple_seq_add_stmt (&new_seq
, x
);
1805 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure (inner
));
1806 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1808 gimple_try_set_cleanup (tp
, new_seq
);
1810 return frob_into_branch_around (tp
, this_region
, NULL
);
1813 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1814 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1815 plus the exception region trees that record all the magic. */
1818 lower_eh_must_not_throw (struct leh_state
*state
, gimple tp
)
1820 struct leh_state this_state
= *state
;
1822 if (flag_exceptions
)
1824 gimple inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1825 eh_region this_region
;
1827 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1828 this_region
->u
.must_not_throw
.failure_decl
1829 = gimple_eh_must_not_throw_fndecl (inner
);
1830 this_region
->u
.must_not_throw
.failure_loc
= gimple_location (tp
);
1832 /* In order to get mangling applied to this decl, we must mark it
1833 used now. Otherwise, pass_ipa_free_lang_data won't think it
1835 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1837 this_state
.cur_region
= this_region
;
1840 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1842 return gimple_try_eval (tp
);
1845 /* Implement a cleanup expression. This is similar to try-finally,
1846 except that we only execute the cleanup block for exception edges. */
1849 lower_cleanup (struct leh_state
*state
, gimple tp
)
1851 struct leh_state this_state
= *state
;
1852 eh_region this_region
= NULL
;
1853 struct leh_tf_state fake_tf
;
1855 bool cleanup_dead
= cleanup_is_dead_in (state
->cur_region
);
1857 if (flag_exceptions
&& !cleanup_dead
)
1859 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1860 this_state
.cur_region
= this_region
;
1863 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1865 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1866 return gimple_try_eval (tp
);
1868 /* Build enough of a try-finally state so that we can reuse
1869 honor_protect_cleanup_actions. */
1870 memset (&fake_tf
, 0, sizeof (fake_tf
));
1871 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1872 fake_tf
.outer
= state
;
1873 fake_tf
.region
= this_region
;
1874 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1875 fake_tf
.may_throw
= true;
1877 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1879 if (fake_tf
.may_throw
)
1881 /* In this case honor_protect_cleanup_actions had nothing to do,
1882 and we should process this normally. */
1883 lower_eh_constructs_1 (state
, gimple_try_cleanup (tp
));
1884 result
= frob_into_branch_around (tp
, this_region
,
1885 fake_tf
.fallthru_label
);
1889 /* In this case honor_protect_cleanup_actions did nearly all of
1890 the work. All we have left is to append the fallthru_label. */
1892 result
= gimple_try_eval (tp
);
1893 if (fake_tf
.fallthru_label
)
1895 gimple x
= gimple_build_label (fake_tf
.fallthru_label
);
1896 gimple_seq_add_stmt (&result
, x
);
1902 /* Main loop for lowering eh constructs. Also moves gsi to the next
1906 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1910 gimple stmt
= gsi_stmt (*gsi
);
1912 switch (gimple_code (stmt
))
1916 tree fndecl
= gimple_call_fndecl (stmt
);
1919 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1920 switch (DECL_FUNCTION_CODE (fndecl
))
1922 case BUILT_IN_EH_POINTER
:
1923 /* The front end may have generated a call to
1924 __builtin_eh_pointer (0) within a catch region. Replace
1925 this zero argument with the current catch region number. */
1926 if (state
->ehp_region
)
1928 tree nr
= build_int_cst (integer_type_node
,
1929 state
->ehp_region
->index
);
1930 gimple_call_set_arg (stmt
, 0, nr
);
1934 /* The user has dome something silly. Remove it. */
1935 rhs
= null_pointer_node
;
1940 case BUILT_IN_EH_FILTER
:
1941 /* ??? This should never appear, but since it's a builtin it
1942 is accessible to abuse by users. Just remove it and
1943 replace the use with the arbitrary value zero. */
1944 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
1946 lhs
= gimple_call_lhs (stmt
);
1947 x
= gimple_build_assign (lhs
, rhs
);
1948 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
1951 case BUILT_IN_EH_COPY_VALUES
:
1952 /* Likewise this should not appear. Remove it. */
1953 gsi_remove (gsi
, true);
1963 /* If the stmt can throw use a new temporary for the assignment
1964 to a LHS. This makes sure the old value of the LHS is
1965 available on the EH edge. Only do so for statements that
1966 potentially fall thru (no noreturn calls e.g.), otherwise
1967 this new assignment might create fake fallthru regions. */
1968 if (stmt_could_throw_p (stmt
)
1969 && gimple_has_lhs (stmt
)
1970 && gimple_stmt_may_fallthru (stmt
)
1971 && !tree_could_throw_p (gimple_get_lhs (stmt
))
1972 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
1974 tree lhs
= gimple_get_lhs (stmt
);
1975 tree tmp
= create_tmp_var (TREE_TYPE (lhs
), NULL
);
1976 gimple s
= gimple_build_assign (lhs
, tmp
);
1977 gimple_set_location (s
, gimple_location (stmt
));
1978 gimple_set_block (s
, gimple_block (stmt
));
1979 gimple_set_lhs (stmt
, tmp
);
1980 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
1981 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
1982 DECL_GIMPLE_REG_P (tmp
) = 1;
1983 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
1985 /* Look for things that can throw exceptions, and record them. */
1986 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
1988 record_stmt_eh_region (state
->cur_region
, stmt
);
1989 note_eh_region_may_contain_throw (state
->cur_region
);
1996 maybe_record_in_goto_queue (state
, stmt
);
2000 verify_norecord_switch_expr (state
, stmt
);
2004 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
2005 replace
= lower_try_finally (state
, stmt
);
2008 x
= gimple_seq_first_stmt (gimple_try_cleanup (stmt
));
2011 replace
= gimple_try_eval (stmt
);
2012 lower_eh_constructs_1 (state
, replace
);
2015 switch (gimple_code (x
))
2018 replace
= lower_catch (state
, stmt
);
2020 case GIMPLE_EH_FILTER
:
2021 replace
= lower_eh_filter (state
, stmt
);
2023 case GIMPLE_EH_MUST_NOT_THROW
:
2024 replace
= lower_eh_must_not_throw (state
, stmt
);
2026 case GIMPLE_EH_ELSE
:
2027 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2030 replace
= lower_cleanup (state
, stmt
);
2035 /* Remove the old stmt and insert the transformed sequence
2037 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2038 gsi_remove (gsi
, true);
2040 /* Return since we don't want gsi_next () */
2043 case GIMPLE_EH_ELSE
:
2044 /* We should be eliminating this in lower_try_finally et al. */
2048 /* A type, a decl, or some kind of statement that we're not
2049 interested in. Don't walk them. */
2056 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2059 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq seq
)
2061 gimple_stmt_iterator gsi
;
2062 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
);)
2063 lower_eh_constructs_2 (state
, &gsi
);
2067 lower_eh_constructs (void)
2069 struct leh_state null_state
;
2072 bodyp
= gimple_body (current_function_decl
);
2076 finally_tree
= htab_create (31, struct_ptr_hash
, struct_ptr_eq
, free
);
2077 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2078 memset (&null_state
, 0, sizeof (null_state
));
2080 collect_finally_tree_1 (bodyp
, NULL
);
2081 lower_eh_constructs_1 (&null_state
, bodyp
);
2083 /* We assume there's a return statement, or something, at the end of
2084 the function, and thus ploping the EH sequence afterward won't
2086 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2087 gimple_seq_add_seq (&bodyp
, eh_seq
);
2089 /* We assume that since BODYP already existed, adding EH_SEQ to it
2090 didn't change its value, and we don't have to re-set the function. */
2091 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2093 htab_delete (finally_tree
);
2094 BITMAP_FREE (eh_region_may_contain_throw_map
);
2097 /* If this function needs a language specific EH personality routine
2098 and the frontend didn't already set one do so now. */
2099 if (function_needs_eh_personality (cfun
) == eh_personality_lang
2100 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2101 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2102 = lang_hooks
.eh_personality ();
2107 struct gimple_opt_pass pass_lower_eh
=
2113 lower_eh_constructs
, /* execute */
2116 0, /* static_pass_number */
2117 TV_TREE_EH
, /* tv_id */
2118 PROP_gimple_lcf
, /* properties_required */
2119 PROP_gimple_leh
, /* properties_provided */
2120 0, /* properties_destroyed */
2121 0, /* todo_flags_start */
2122 0 /* todo_flags_finish */
2126 /* Create the multiple edges from an EH_DISPATCH statement to all of
2127 the possible handlers for its EH region. Return true if there's
2128 no fallthru edge; false if there is. */
2131 make_eh_dispatch_edges (gimple stmt
)
2135 basic_block src
, dst
;
2137 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2138 src
= gimple_bb (stmt
);
2143 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2145 dst
= label_to_block (c
->label
);
2146 make_edge (src
, dst
, 0);
2148 /* A catch-all handler doesn't have a fallthru. */
2149 if (c
->type_list
== NULL
)
2154 case ERT_ALLOWED_EXCEPTIONS
:
2155 dst
= label_to_block (r
->u
.allowed
.label
);
2156 make_edge (src
, dst
, 0);
2166 /* Create the single EH edge from STMT to its nearest landing pad,
2167 if there is such a landing pad within the current function. */
2170 make_eh_edges (gimple stmt
)
2172 basic_block src
, dst
;
2176 lp_nr
= lookup_stmt_eh_lp (stmt
);
2180 lp
= get_eh_landing_pad_from_number (lp_nr
);
2181 gcc_assert (lp
!= NULL
);
2183 src
= gimple_bb (stmt
);
2184 dst
= label_to_block (lp
->post_landing_pad
);
2185 make_edge (src
, dst
, EDGE_EH
);
2188 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2189 do not actually perform the final edge redirection.
2191 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2192 we intend to change the destination EH region as well; this means
2193 EH_LANDING_PAD_NR must already be set on the destination block label.
2194 If false, we're being called from generic cfg manipulation code and we
2195 should preserve our place within the region tree. */
2198 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2200 eh_landing_pad old_lp
, new_lp
;
2203 int old_lp_nr
, new_lp_nr
;
2204 tree old_label
, new_label
;
2208 old_bb
= edge_in
->dest
;
2209 old_label
= gimple_block_label (old_bb
);
2210 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2211 gcc_assert (old_lp_nr
> 0);
2212 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2214 throw_stmt
= last_stmt (edge_in
->src
);
2215 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2217 new_label
= gimple_block_label (new_bb
);
2219 /* Look for an existing region that might be using NEW_BB already. */
2220 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2223 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2224 gcc_assert (new_lp
);
2226 /* Unless CHANGE_REGION is true, the new and old landing pad
2227 had better be associated with the same EH region. */
2228 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2233 gcc_assert (!change_region
);
2236 /* Notice when we redirect the last EH edge away from OLD_BB. */
2237 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2238 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2243 /* NEW_LP already exists. If there are still edges into OLD_LP,
2244 there's nothing to do with the EH tree. If there are no more
2245 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2246 If CHANGE_REGION is true, then our caller is expecting to remove
2248 if (e
== NULL
&& !change_region
)
2249 remove_eh_landing_pad (old_lp
);
2253 /* No correct landing pad exists. If there are no more edges
2254 into OLD_LP, then we can simply re-use the existing landing pad.
2255 Otherwise, we have to create a new landing pad. */
2258 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2262 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2263 new_lp
->post_landing_pad
= new_label
;
2264 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2267 /* Maybe move the throwing statement to the new region. */
2268 if (old_lp
!= new_lp
)
2270 remove_stmt_from_eh_lp (throw_stmt
);
2271 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2275 /* Redirect EH edge E to NEW_BB. */
2278 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2280 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2281 return ssa_redirect_edge (edge_in
, new_bb
);
2284 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2285 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2286 The actual edge update will happen in the caller. */
2289 redirect_eh_dispatch_edge (gimple stmt
, edge e
, basic_block new_bb
)
2291 tree new_lab
= gimple_block_label (new_bb
);
2292 bool any_changed
= false;
2297 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2301 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2303 old_bb
= label_to_block (c
->label
);
2304 if (old_bb
== e
->dest
)
2312 case ERT_ALLOWED_EXCEPTIONS
:
2313 old_bb
= label_to_block (r
->u
.allowed
.label
);
2314 gcc_assert (old_bb
== e
->dest
);
2315 r
->u
.allowed
.label
= new_lab
;
2323 gcc_assert (any_changed
);
2326 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2329 operation_could_trap_helper_p (enum tree_code op
,
2340 case TRUNC_DIV_EXPR
:
2342 case FLOOR_DIV_EXPR
:
2343 case ROUND_DIV_EXPR
:
2344 case EXACT_DIV_EXPR
:
2346 case FLOOR_MOD_EXPR
:
2347 case ROUND_MOD_EXPR
:
2348 case TRUNC_MOD_EXPR
:
2350 if (honor_snans
|| honor_trapv
)
2353 return flag_trapping_math
;
2354 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2363 /* Some floating point comparisons may trap. */
2368 case UNORDERED_EXPR
:
2378 case FIX_TRUNC_EXPR
:
2379 /* Conversion of floating point might trap. */
2385 /* These operations don't trap with floating point. */
2393 /* Any floating arithmetic may trap. */
2394 if (fp_operation
&& flag_trapping_math
)
2402 /* Constructing an object cannot trap. */
2406 /* Any floating arithmetic may trap. */
2407 if (fp_operation
&& flag_trapping_math
)
2415 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2416 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2417 type operands that may trap. If OP is a division operator, DIVISOR contains
2418 the value of the divisor. */
2421 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2424 bool honor_nans
= (fp_operation
&& flag_trapping_math
2425 && !flag_finite_math_only
);
2426 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2429 if (TREE_CODE_CLASS (op
) != tcc_comparison
2430 && TREE_CODE_CLASS (op
) != tcc_unary
2431 && TREE_CODE_CLASS (op
) != tcc_binary
)
2434 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2435 honor_nans
, honor_snans
, divisor
,
2439 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2440 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2441 This routine expects only GIMPLE lhs or rhs input. */
2444 tree_could_trap_p (tree expr
)
2446 enum tree_code code
;
2447 bool fp_operation
= false;
2448 bool honor_trapv
= false;
2449 tree t
, base
, div
= NULL_TREE
;
2454 code
= TREE_CODE (expr
);
2455 t
= TREE_TYPE (expr
);
2459 if (COMPARISON_CLASS_P (expr
))
2460 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2462 fp_operation
= FLOAT_TYPE_P (t
);
2463 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2466 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2467 div
= TREE_OPERAND (expr
, 1);
2468 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2474 case TARGET_MEM_REF
:
2475 if (TREE_CODE (TMR_BASE (expr
)) == ADDR_EXPR
2476 && !TMR_INDEX (expr
) && !TMR_INDEX2 (expr
))
2478 return !TREE_THIS_NOTRAP (expr
);
2484 case VIEW_CONVERT_EXPR
:
2485 case WITH_SIZE_EXPR
:
2486 expr
= TREE_OPERAND (expr
, 0);
2487 code
= TREE_CODE (expr
);
2490 case ARRAY_RANGE_REF
:
2491 base
= TREE_OPERAND (expr
, 0);
2492 if (tree_could_trap_p (base
))
2494 if (TREE_THIS_NOTRAP (expr
))
2496 return !range_in_array_bounds_p (expr
);
2499 base
= TREE_OPERAND (expr
, 0);
2500 if (tree_could_trap_p (base
))
2502 if (TREE_THIS_NOTRAP (expr
))
2504 return !in_array_bounds_p (expr
);
2507 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2511 return !TREE_THIS_NOTRAP (expr
);
2514 return TREE_THIS_VOLATILE (expr
);
2517 t
= get_callee_fndecl (expr
);
2518 /* Assume that calls to weak functions may trap. */
2519 if (!t
|| !DECL_P (t
))
2522 return tree_could_trap_p (t
);
2526 /* Assume that accesses to weak functions may trap, unless we know
2527 they are certainly defined in current TU or in some other
2529 if (DECL_WEAK (expr
))
2531 struct cgraph_node
*node
;
2532 if (!DECL_EXTERNAL (expr
))
2534 node
= cgraph_function_node (cgraph_get_node (expr
), NULL
);
2535 if (node
&& node
->in_other_partition
)
2542 /* Assume that accesses to weak vars may trap, unless we know
2543 they are certainly defined in current TU or in some other
2545 if (DECL_WEAK (expr
))
2547 struct varpool_node
*node
;
2548 if (!DECL_EXTERNAL (expr
))
2550 node
= varpool_variable_node (varpool_get_node (expr
), NULL
);
2551 if (node
&& node
->in_other_partition
)
2563 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2564 an assignment or a conditional) may throw. */
2567 stmt_could_throw_1_p (gimple stmt
)
2569 enum tree_code code
= gimple_expr_code (stmt
);
2570 bool honor_nans
= false;
2571 bool honor_snans
= false;
2572 bool fp_operation
= false;
2573 bool honor_trapv
= false;
2578 if (TREE_CODE_CLASS (code
) == tcc_comparison
2579 || TREE_CODE_CLASS (code
) == tcc_unary
2580 || TREE_CODE_CLASS (code
) == tcc_binary
)
2582 if (is_gimple_assign (stmt
)
2583 && TREE_CODE_CLASS (code
) == tcc_comparison
)
2584 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2585 else if (gimple_code (stmt
) == GIMPLE_COND
)
2586 t
= TREE_TYPE (gimple_cond_lhs (stmt
));
2588 t
= gimple_expr_type (stmt
);
2589 fp_operation
= FLOAT_TYPE_P (t
);
2592 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2593 honor_snans
= flag_signaling_nans
!= 0;
2595 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2599 /* Check if the main expression may trap. */
2600 t
= is_gimple_assign (stmt
) ? gimple_assign_rhs2 (stmt
) : NULL
;
2601 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2602 honor_nans
, honor_snans
, t
,
2607 /* If the expression does not trap, see if any of the individual operands may
2609 for (i
= 0; i
< gimple_num_ops (stmt
); i
++)
2610 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2617 /* Return true if statement STMT could throw an exception. */
2620 stmt_could_throw_p (gimple stmt
)
2622 if (!flag_exceptions
)
2625 /* The only statements that can throw an exception are assignments,
2626 conditionals, calls, resx, and asms. */
2627 switch (gimple_code (stmt
))
2633 return !gimple_call_nothrow_p (stmt
);
2637 if (!cfun
->can_throw_non_call_exceptions
)
2639 return stmt_could_throw_1_p (stmt
);
2642 if (!cfun
->can_throw_non_call_exceptions
)
2644 return gimple_asm_volatile_p (stmt
);
2652 /* Return true if expression T could throw an exception. */
2655 tree_could_throw_p (tree t
)
2657 if (!flag_exceptions
)
2659 if (TREE_CODE (t
) == MODIFY_EXPR
)
2661 if (cfun
->can_throw_non_call_exceptions
2662 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2664 t
= TREE_OPERAND (t
, 1);
2667 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2668 t
= TREE_OPERAND (t
, 0);
2669 if (TREE_CODE (t
) == CALL_EXPR
)
2670 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2671 if (cfun
->can_throw_non_call_exceptions
)
2672 return tree_could_trap_p (t
);
2676 /* Return true if STMT can throw an exception that is not caught within
2677 the current function (CFUN). */
2680 stmt_can_throw_external (gimple stmt
)
2684 if (!stmt_could_throw_p (stmt
))
2687 lp_nr
= lookup_stmt_eh_lp (stmt
);
2691 /* Return true if STMT can throw an exception that is caught within
2692 the current function (CFUN). */
2695 stmt_can_throw_internal (gimple stmt
)
2699 if (!stmt_could_throw_p (stmt
))
2702 lp_nr
= lookup_stmt_eh_lp (stmt
);
2706 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2707 remove any entry it might have from the EH table. Return true if
2708 any change was made. */
2711 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple stmt
)
2713 if (stmt_could_throw_p (stmt
))
2715 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2718 /* Likewise, but always use the current function. */
2721 maybe_clean_eh_stmt (gimple stmt
)
2723 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2726 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2727 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2728 in the table if it should be in there. Return TRUE if a replacement was
2729 done that my require an EH edge purge. */
2732 maybe_clean_or_replace_eh_stmt (gimple old_stmt
, gimple new_stmt
)
2734 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2738 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2740 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2743 remove_stmt_from_eh_lp (old_stmt
);
2744 if (new_stmt_could_throw
)
2746 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2756 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statment NEW_STMT
2757 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2758 operand is the return value of duplicate_eh_regions. */
2761 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple new_stmt
,
2762 struct function
*old_fun
, gimple old_stmt
,
2763 struct pointer_map_t
*map
, int default_lp_nr
)
2765 int old_lp_nr
, new_lp_nr
;
2768 if (!stmt_could_throw_p (new_stmt
))
2771 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2774 if (default_lp_nr
== 0)
2776 new_lp_nr
= default_lp_nr
;
2778 else if (old_lp_nr
> 0)
2780 eh_landing_pad old_lp
, new_lp
;
2782 old_lp
= VEC_index (eh_landing_pad
, old_fun
->eh
->lp_array
, old_lp_nr
);
2783 slot
= pointer_map_contains (map
, old_lp
);
2784 new_lp
= (eh_landing_pad
) *slot
;
2785 new_lp_nr
= new_lp
->index
;
2789 eh_region old_r
, new_r
;
2791 old_r
= VEC_index (eh_region
, old_fun
->eh
->region_array
, -old_lp_nr
);
2792 slot
= pointer_map_contains (map
, old_r
);
2793 new_r
= (eh_region
) *slot
;
2794 new_lp_nr
= -new_r
->index
;
2797 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2801 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2802 and thus no remapping is required. */
2805 maybe_duplicate_eh_stmt (gimple new_stmt
, gimple old_stmt
)
2809 if (!stmt_could_throw_p (new_stmt
))
2812 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2816 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2820 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2821 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2822 this only handles handlers consisting of a single call, as that's the
2823 important case for C++: a destructor call for a particular object showing
2824 up in multiple handlers. */
2827 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2829 gimple_stmt_iterator gsi
;
2833 gsi
= gsi_start (oneh
);
2834 if (!gsi_one_before_end_p (gsi
))
2836 ones
= gsi_stmt (gsi
);
2838 gsi
= gsi_start (twoh
);
2839 if (!gsi_one_before_end_p (gsi
))
2841 twos
= gsi_stmt (gsi
);
2843 if (!is_gimple_call (ones
)
2844 || !is_gimple_call (twos
)
2845 || gimple_call_lhs (ones
)
2846 || gimple_call_lhs (twos
)
2847 || gimple_call_chain (ones
)
2848 || gimple_call_chain (twos
)
2849 || !gimple_call_same_target_p (ones
, twos
)
2850 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
2853 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
2854 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
2855 gimple_call_arg (twos
, ai
), 0))
2862 try { A() } finally { try { ~B() } catch { ~A() } }
2863 try { ... } finally { ~A() }
2865 try { A() } catch { ~B() }
2866 try { ~B() ... } finally { ~A() }
2868 This occurs frequently in C++, where A is a local variable and B is a
2869 temporary used in the initializer for A. */
2872 optimize_double_finally (gimple one
, gimple two
)
2875 gimple_stmt_iterator gsi
;
2877 gsi
= gsi_start (gimple_try_cleanup (one
));
2878 if (!gsi_one_before_end_p (gsi
))
2881 oneh
= gsi_stmt (gsi
);
2882 if (gimple_code (oneh
) != GIMPLE_TRY
2883 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
2886 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
2888 gimple_seq seq
= gimple_try_eval (oneh
);
2890 gimple_try_set_cleanup (one
, seq
);
2891 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
2892 seq
= copy_gimple_seq_and_replace_locals (seq
);
2893 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
2894 gimple_try_set_eval (two
, seq
);
2898 /* Perform EH refactoring optimizations that are simpler to do when code
2899 flow has been lowered but EH structures haven't. */
2902 refactor_eh_r (gimple_seq seq
)
2904 gimple_stmt_iterator gsi
;
2909 gsi
= gsi_start (seq
);
2913 if (gsi_end_p (gsi
))
2916 two
= gsi_stmt (gsi
);
2919 && gimple_code (one
) == GIMPLE_TRY
2920 && gimple_code (two
) == GIMPLE_TRY
2921 && gimple_try_kind (one
) == GIMPLE_TRY_FINALLY
2922 && gimple_try_kind (two
) == GIMPLE_TRY_FINALLY
)
2923 optimize_double_finally (one
, two
);
2925 switch (gimple_code (one
))
2928 refactor_eh_r (gimple_try_eval (one
));
2929 refactor_eh_r (gimple_try_cleanup (one
));
2932 refactor_eh_r (gimple_catch_handler (one
));
2934 case GIMPLE_EH_FILTER
:
2935 refactor_eh_r (gimple_eh_filter_failure (one
));
2937 case GIMPLE_EH_ELSE
:
2938 refactor_eh_r (gimple_eh_else_n_body (one
));
2939 refactor_eh_r (gimple_eh_else_e_body (one
));
2954 refactor_eh_r (gimple_body (current_function_decl
));
2959 gate_refactor_eh (void)
2961 return flag_exceptions
!= 0;
2964 struct gimple_opt_pass pass_refactor_eh
=
2969 gate_refactor_eh
, /* gate */
2970 refactor_eh
, /* execute */
2973 0, /* static_pass_number */
2974 TV_TREE_EH
, /* tv_id */
2975 PROP_gimple_lcf
, /* properties_required */
2976 0, /* properties_provided */
2977 0, /* properties_destroyed */
2978 0, /* todo_flags_start */
2979 0 /* todo_flags_finish */
2983 /* At the end of gimple optimization, we can lower RESX. */
2986 lower_resx (basic_block bb
, gimple stmt
, struct pointer_map_t
*mnt_map
)
2989 eh_region src_r
, dst_r
;
2990 gimple_stmt_iterator gsi
;
2995 lp_nr
= lookup_stmt_eh_lp (stmt
);
2997 dst_r
= get_eh_region_from_lp_number (lp_nr
);
3001 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
3002 gsi
= gsi_last_bb (bb
);
3006 /* We can wind up with no source region when pass_cleanup_eh shows
3007 that there are no entries into an eh region and deletes it, but
3008 then the block that contains the resx isn't removed. This can
3009 happen without optimization when the switch statement created by
3010 lower_try_finally_switch isn't simplified to remove the eh case.
3012 Resolve this by expanding the resx node to an abort. */
3014 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3015 x
= gimple_build_call (fn
, 0);
3016 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3018 while (EDGE_COUNT (bb
->succs
) > 0)
3019 remove_edge (EDGE_SUCC (bb
, 0));
3023 /* When we have a destination region, we resolve this by copying
3024 the excptr and filter values into place, and changing the edge
3025 to immediately after the landing pad. */
3034 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3035 the failure decl into a new block, if needed. */
3036 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3038 slot
= pointer_map_contains (mnt_map
, dst_r
);
3041 gimple_stmt_iterator gsi2
;
3043 new_bb
= create_empty_bb (bb
);
3044 lab
= gimple_block_label (new_bb
);
3045 gsi2
= gsi_start_bb (new_bb
);
3047 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3048 x
= gimple_build_call (fn
, 0);
3049 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3050 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3052 slot
= pointer_map_insert (mnt_map
, dst_r
);
3058 new_bb
= label_to_block (lab
);
3061 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3062 e
= make_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3063 e
->count
= bb
->count
;
3064 e
->probability
= REG_BR_PROB_BASE
;
3069 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3071 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3072 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3073 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3074 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3076 /* Update the flags for the outgoing edge. */
3077 e
= single_succ_edge (bb
);
3078 gcc_assert (e
->flags
& EDGE_EH
);
3079 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3081 /* If there are no more EH users of the landing pad, delete it. */
3082 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3083 if (e
->flags
& EDGE_EH
)
3087 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3088 remove_eh_landing_pad (lp
);
3098 /* When we don't have a destination region, this exception escapes
3099 up the call chain. We resolve this by generating a call to the
3100 _Unwind_Resume library function. */
3102 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3103 with no arguments for C++ and Java. Check for that. */
3104 if (src_r
->use_cxa_end_cleanup
)
3106 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3107 x
= gimple_build_call (fn
, 0);
3108 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3112 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3113 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3114 x
= gimple_build_call (fn
, 1, src_nr
);
3115 var
= create_tmp_var (ptr_type_node
, NULL
);
3116 var
= make_ssa_name (var
, x
);
3117 gimple_call_set_lhs (x
, var
);
3118 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3120 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3121 x
= gimple_build_call (fn
, 1, var
);
3122 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3125 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3128 gsi_remove (&gsi
, true);
3134 execute_lower_resx (void)
3137 struct pointer_map_t
*mnt_map
;
3138 bool dominance_invalidated
= false;
3139 bool any_rewritten
= false;
3141 mnt_map
= pointer_map_create ();
3145 gimple last
= last_stmt (bb
);
3146 if (last
&& is_gimple_resx (last
))
3148 dominance_invalidated
|= lower_resx (bb
, last
, mnt_map
);
3149 any_rewritten
= true;
3153 pointer_map_destroy (mnt_map
);
3155 if (dominance_invalidated
)
3157 free_dominance_info (CDI_DOMINATORS
);
3158 free_dominance_info (CDI_POST_DOMINATORS
);
3161 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3165 gate_lower_resx (void)
3167 return flag_exceptions
!= 0;
3170 struct gimple_opt_pass pass_lower_resx
=
3175 gate_lower_resx
, /* gate */
3176 execute_lower_resx
, /* execute */
3179 0, /* static_pass_number */
3180 TV_TREE_EH
, /* tv_id */
3181 PROP_gimple_lcf
, /* properties_required */
3182 0, /* properties_provided */
3183 0, /* properties_destroyed */
3184 0, /* todo_flags_start */
3185 TODO_verify_flow
/* todo_flags_finish */
3189 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3193 optimize_clobbers (basic_block bb
)
3195 gimple_stmt_iterator gsi
= gsi_last_bb (bb
);
3196 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3198 gimple stmt
= gsi_stmt (gsi
);
3199 if (is_gimple_debug (stmt
))
3201 if (!gimple_clobber_p (stmt
)
3202 || TREE_CODE (gimple_assign_lhs (stmt
)) == SSA_NAME
)
3204 unlink_stmt_vdef (stmt
);
3205 gsi_remove (&gsi
, true);
3206 release_defs (stmt
);
3210 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3211 internal throw to successor BB. */
3214 sink_clobbers (basic_block bb
)
3218 gimple_stmt_iterator gsi
, dgsi
;
3220 bool any_clobbers
= false;
3222 /* Only optimize if BB has a single EH successor and
3223 all predecessor edges are EH too. */
3224 if (!single_succ_p (bb
)
3225 || (single_succ_edge (bb
)->flags
& EDGE_EH
) == 0)
3228 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3230 if ((e
->flags
& EDGE_EH
) == 0)
3234 /* And BB contains only CLOBBER stmts before the final
3236 gsi
= gsi_last_bb (bb
);
3237 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3239 gimple stmt
= gsi_stmt (gsi
);
3240 if (is_gimple_debug (stmt
))
3242 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3244 if (!gimple_clobber_p (stmt
)
3245 || TREE_CODE (gimple_assign_lhs (stmt
)) == SSA_NAME
)
3247 any_clobbers
= true;
3252 succbb
= single_succ (bb
);
3253 dgsi
= gsi_after_labels (succbb
);
3254 gsi
= gsi_last_bb (bb
);
3255 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3257 gimple stmt
= gsi_stmt (gsi
);
3259 if (is_gimple_debug (stmt
))
3261 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3263 unlink_stmt_vdef (stmt
);
3264 gsi_remove (&gsi
, false);
3265 vdef
= gimple_vdef (stmt
);
3266 if (vdef
&& TREE_CODE (vdef
) == SSA_NAME
)
3268 vdef
= SSA_NAME_VAR (vdef
);
3269 mark_sym_for_renaming (vdef
);
3270 gimple_set_vdef (stmt
, vdef
);
3271 gimple_set_vuse (stmt
, vdef
);
3273 release_defs (stmt
);
3274 gsi_insert_before (&dgsi
, stmt
, GSI_SAME_STMT
);
3277 return TODO_update_ssa_only_virtuals
;
3280 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3281 we have found some duplicate labels and removed some edges. */
3284 lower_eh_dispatch (basic_block src
, gimple stmt
)
3286 gimple_stmt_iterator gsi
;
3291 bool redirected
= false;
3293 region_nr
= gimple_eh_dispatch_region (stmt
);
3294 r
= get_eh_region_from_number (region_nr
);
3296 gsi
= gsi_last_bb (src
);
3302 VEC (tree
, heap
) *labels
= NULL
;
3303 tree default_label
= NULL
;
3307 struct pointer_set_t
*seen_values
= pointer_set_create ();
3309 /* Collect the labels for a switch. Zero the post_landing_pad
3310 field becase we'll no longer have anything keeping these labels
3311 in existance and the optimizer will be free to merge these
3313 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3315 tree tp_node
, flt_node
, lab
= c
->label
;
3316 bool have_label
= false;
3319 tp_node
= c
->type_list
;
3320 flt_node
= c
->filter_list
;
3322 if (tp_node
== NULL
)
3324 default_label
= lab
;
3329 /* Filter out duplicate labels that arise when this handler
3330 is shadowed by an earlier one. When no labels are
3331 attached to the handler anymore, we remove
3332 the corresponding edge and then we delete unreachable
3333 blocks at the end of this pass. */
3334 if (! pointer_set_contains (seen_values
, TREE_VALUE (flt_node
)))
3336 tree t
= build_case_label (TREE_VALUE (flt_node
),
3338 VEC_safe_push (tree
, heap
, labels
, t
);
3339 pointer_set_insert (seen_values
, TREE_VALUE (flt_node
));
3343 tp_node
= TREE_CHAIN (tp_node
);
3344 flt_node
= TREE_CHAIN (flt_node
);
3349 remove_edge (find_edge (src
, label_to_block (lab
)));
3354 /* Clean up the edge flags. */
3355 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3357 if (e
->flags
& EDGE_FALLTHRU
)
3359 /* If there was no catch-all, use the fallthru edge. */
3360 if (default_label
== NULL
)
3361 default_label
= gimple_block_label (e
->dest
);
3362 e
->flags
&= ~EDGE_FALLTHRU
;
3365 gcc_assert (default_label
!= NULL
);
3367 /* Don't generate a switch if there's only a default case.
3368 This is common in the form of try { A; } catch (...) { B; }. */
3371 e
= single_succ_edge (src
);
3372 e
->flags
|= EDGE_FALLTHRU
;
3376 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3377 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3379 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3380 filter
= make_ssa_name (filter
, x
);
3381 gimple_call_set_lhs (x
, filter
);
3382 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3384 /* Turn the default label into a default case. */
3385 default_label
= build_case_label (NULL
, NULL
, default_label
);
3386 sort_case_labels (labels
);
3388 x
= gimple_build_switch_vec (filter
, default_label
, labels
);
3389 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3391 VEC_free (tree
, heap
, labels
);
3393 pointer_set_destroy (seen_values
);
3397 case ERT_ALLOWED_EXCEPTIONS
:
3399 edge b_e
= BRANCH_EDGE (src
);
3400 edge f_e
= FALLTHRU_EDGE (src
);
3402 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3403 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3405 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3406 filter
= make_ssa_name (filter
, x
);
3407 gimple_call_set_lhs (x
, filter
);
3408 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3410 r
->u
.allowed
.label
= NULL
;
3411 x
= gimple_build_cond (EQ_EXPR
, filter
,
3412 build_int_cst (TREE_TYPE (filter
),
3413 r
->u
.allowed
.filter
),
3414 NULL_TREE
, NULL_TREE
);
3415 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3417 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3418 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3426 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3427 gsi_remove (&gsi
, true);
3432 execute_lower_eh_dispatch (void)
3436 bool redirected
= false;
3438 assign_filter_values ();
3442 gimple last
= last_stmt (bb
);
3445 if (gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3447 redirected
|= lower_eh_dispatch (bb
, last
);
3448 flags
|= TODO_update_ssa_only_virtuals
;
3450 else if (gimple_code (last
) == GIMPLE_RESX
)
3452 if (stmt_can_throw_external (last
))
3453 optimize_clobbers (bb
);
3455 flags
|= sink_clobbers (bb
);
3460 delete_unreachable_blocks ();
3465 gate_lower_eh_dispatch (void)
3467 return cfun
->eh
->region_tree
!= NULL
;
3470 struct gimple_opt_pass pass_lower_eh_dispatch
=
3474 "ehdisp", /* name */
3475 gate_lower_eh_dispatch
, /* gate */
3476 execute_lower_eh_dispatch
, /* execute */
3479 0, /* static_pass_number */
3480 TV_TREE_EH
, /* tv_id */
3481 PROP_gimple_lcf
, /* properties_required */
3482 0, /* properties_provided */
3483 0, /* properties_destroyed */
3484 0, /* todo_flags_start */
3485 TODO_verify_flow
/* todo_flags_finish */
3489 /* Walk statements, see what regions are really referenced and remove
3490 those that are unused. */
3493 remove_unreachable_handlers (void)
3495 sbitmap r_reachable
, lp_reachable
;
3501 r_reachable
= sbitmap_alloc (VEC_length (eh_region
, cfun
->eh
->region_array
));
3503 = sbitmap_alloc (VEC_length (eh_landing_pad
, cfun
->eh
->lp_array
));
3504 sbitmap_zero (r_reachable
);
3505 sbitmap_zero (lp_reachable
);
3509 gimple_stmt_iterator gsi
;
3511 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3513 gimple stmt
= gsi_stmt (gsi
);
3514 lp_nr
= lookup_stmt_eh_lp (stmt
);
3516 /* Negative LP numbers are MUST_NOT_THROW regions which
3517 are not considered BB enders. */
3519 SET_BIT (r_reachable
, -lp_nr
);
3521 /* Positive LP numbers are real landing pads, are are BB enders. */
3524 gcc_assert (gsi_one_before_end_p (gsi
));
3525 region
= get_eh_region_from_lp_number (lp_nr
);
3526 SET_BIT (r_reachable
, region
->index
);
3527 SET_BIT (lp_reachable
, lp_nr
);
3530 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3531 switch (gimple_code (stmt
))
3534 SET_BIT (r_reachable
, gimple_resx_region (stmt
));
3536 case GIMPLE_EH_DISPATCH
:
3537 SET_BIT (r_reachable
, gimple_eh_dispatch_region (stmt
));
3547 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3548 dump_eh_tree (dump_file
, cfun
);
3549 fprintf (dump_file
, "Reachable regions: ");
3550 dump_sbitmap_file (dump_file
, r_reachable
);
3551 fprintf (dump_file
, "Reachable landing pads: ");
3552 dump_sbitmap_file (dump_file
, lp_reachable
);
3556 VEC_iterate (eh_region
, cfun
->eh
->region_array
, r_nr
, region
); ++r_nr
)
3557 if (region
&& !TEST_BIT (r_reachable
, r_nr
))
3560 fprintf (dump_file
, "Removing unreachable region %d\n", r_nr
);
3561 remove_eh_handler (region
);
3565 VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, lp_nr
, lp
); ++lp_nr
)
3566 if (lp
&& !TEST_BIT (lp_reachable
, lp_nr
))
3569 fprintf (dump_file
, "Removing unreachable landing pad %d\n", lp_nr
);
3570 remove_eh_landing_pad (lp
);
3575 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3576 dump_eh_tree (dump_file
, cfun
);
3577 fprintf (dump_file
, "\n\n");
3580 sbitmap_free (r_reachable
);
3581 sbitmap_free (lp_reachable
);
3583 #ifdef ENABLE_CHECKING
3584 verify_eh_tree (cfun
);
3588 /* Remove unreachable handlers if any landing pads have been removed after
3589 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3592 maybe_remove_unreachable_handlers (void)
3597 if (cfun
->eh
== NULL
)
3600 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3601 if (lp
&& lp
->post_landing_pad
)
3603 if (label_to_block (lp
->post_landing_pad
) == NULL
)
3605 remove_unreachable_handlers ();
3611 /* Remove regions that do not have landing pads. This assumes
3612 that remove_unreachable_handlers has already been run, and
3613 that we've just manipulated the landing pads since then. */
3616 remove_unreachable_handlers_no_lp (void)
3620 sbitmap r_reachable
;
3623 r_reachable
= sbitmap_alloc (VEC_length (eh_region
, cfun
->eh
->region_array
));
3624 sbitmap_zero (r_reachable
);
3628 gimple stmt
= last_stmt (bb
);
3630 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3631 switch (gimple_code (stmt
))
3634 SET_BIT (r_reachable
, gimple_resx_region (stmt
));
3636 case GIMPLE_EH_DISPATCH
:
3637 SET_BIT (r_reachable
, gimple_eh_dispatch_region (stmt
));
3644 for (i
= 1; VEC_iterate (eh_region
, cfun
->eh
->region_array
, i
, r
); ++i
)
3645 if (r
&& r
->landing_pads
== NULL
&& r
->type
!= ERT_MUST_NOT_THROW
3646 && !TEST_BIT (r_reachable
, i
))
3649 fprintf (dump_file
, "Removing unreachable region %d\n", i
);
3650 remove_eh_handler (r
);
3653 sbitmap_free (r_reachable
);
3656 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3657 optimisticaly split all sorts of edges, including EH edges. The
3658 optimization passes in between may not have needed them; if not,
3659 we should undo the split.
3661 Recognize this case by having one EH edge incoming to the BB and
3662 one normal edge outgoing; BB should be empty apart from the
3663 post_landing_pad label.
3665 Note that this is slightly different from the empty handler case
3666 handled by cleanup_empty_eh, in that the actual handler may yet
3667 have actual code but the landing pad has been separated from the
3668 handler. As such, cleanup_empty_eh relies on this transformation
3669 having been done first. */
3672 unsplit_eh (eh_landing_pad lp
)
3674 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3675 gimple_stmt_iterator gsi
;
3678 /* Quickly check the edge counts on BB for singularity. */
3679 if (EDGE_COUNT (bb
->preds
) != 1 || EDGE_COUNT (bb
->succs
) != 1)
3681 e_in
= EDGE_PRED (bb
, 0);
3682 e_out
= EDGE_SUCC (bb
, 0);
3684 /* Input edge must be EH and output edge must be normal. */
3685 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
3688 /* The block must be empty except for the labels and debug insns. */
3689 gsi
= gsi_after_labels (bb
);
3690 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3691 gsi_next_nondebug (&gsi
);
3692 if (!gsi_end_p (gsi
))
3695 /* The destination block must not already have a landing pad
3696 for a different region. */
3697 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3699 gimple stmt
= gsi_stmt (gsi
);
3703 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3705 lab
= gimple_label_label (stmt
);
3706 lp_nr
= EH_LANDING_PAD_NR (lab
);
3707 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3711 /* The new destination block must not already be a destination of
3712 the source block, lest we merge fallthru and eh edges and get
3713 all sorts of confused. */
3714 if (find_edge (e_in
->src
, e_out
->dest
))
3717 /* ??? We can get degenerate phis due to cfg cleanups. I would have
3718 thought this should have been cleaned up by a phicprop pass, but
3719 that doesn't appear to handle virtuals. Propagate by hand. */
3720 if (!gimple_seq_empty_p (phi_nodes (bb
)))
3722 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); )
3724 gimple use_stmt
, phi
= gsi_stmt (gsi
);
3725 tree lhs
= gimple_phi_result (phi
);
3726 tree rhs
= gimple_phi_arg_def (phi
, 0);
3727 use_operand_p use_p
;
3728 imm_use_iterator iter
;
3730 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
3732 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3733 SET_USE (use_p
, rhs
);
3736 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
3737 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
3739 remove_phi_node (&gsi
, true);
3743 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3744 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
3745 lp
->index
, e_out
->dest
->index
);
3747 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
3748 a successor edge, humor it. But do the real CFG change with the
3749 predecessor of E_OUT in order to preserve the ordering of arguments
3750 to the PHI nodes in E_OUT->DEST. */
3751 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
3752 redirect_edge_pred (e_out
, e_in
->src
);
3753 e_out
->flags
= e_in
->flags
;
3754 e_out
->probability
= e_in
->probability
;
3755 e_out
->count
= e_in
->count
;
3761 /* Examine each landing pad block and see if it matches unsplit_eh. */
3764 unsplit_all_eh (void)
3766 bool changed
= false;
3770 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3772 changed
|= unsplit_eh (lp
);
3777 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
3778 to OLD_BB to NEW_BB; return true on success, false on failure.
3780 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
3781 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
3782 Virtual PHIs may be deleted and marked for renaming. */
3785 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
3786 edge old_bb_out
, bool change_region
)
3788 gimple_stmt_iterator ngsi
, ogsi
;
3791 bitmap rename_virts
;
3792 bitmap ophi_handled
;
3794 /* The destination block must not be a regular successor for any
3795 of the preds of the landing pad. Thus, avoid turning
3805 which CFG verification would choke on. See PR45172 and PR51089. */
3806 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3807 if (find_edge (e
->src
, new_bb
))
3810 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3811 redirect_edge_var_map_clear (e
);
3813 ophi_handled
= BITMAP_ALLOC (NULL
);
3814 rename_virts
= BITMAP_ALLOC (NULL
);
3816 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
3817 for the edges we're going to move. */
3818 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
3820 gimple ophi
, nphi
= gsi_stmt (ngsi
);
3823 nresult
= gimple_phi_result (nphi
);
3824 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
3826 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
3827 the source ssa_name. */
3829 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3831 ophi
= gsi_stmt (ogsi
);
3832 if (gimple_phi_result (ophi
) == nop
)
3837 /* If we did find the corresponding PHI, copy those inputs. */
3840 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
3841 if (!has_single_use (nop
))
3843 imm_use_iterator imm_iter
;
3844 use_operand_p use_p
;
3846 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
3848 if (!gimple_debug_bind_p (USE_STMT (use_p
))
3849 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
3850 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
3854 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
3855 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3860 if ((e
->flags
& EDGE_EH
) == 0)
3862 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
3863 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
3864 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
3867 /* If we didn't find the PHI, but it's a VOP, remember to rename
3868 it later, assuming all other tests succeed. */
3869 else if (!is_gimple_reg (nresult
))
3870 bitmap_set_bit (rename_virts
, SSA_NAME_VERSION (nresult
));
3871 /* If we didn't find the PHI, and it's a real variable, we know
3872 from the fact that OLD_BB is tree_empty_eh_handler_p that the
3873 variable is unchanged from input to the block and we can simply
3874 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
3878 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
3879 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3880 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
3884 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
3885 we don't know what values from the other edges into NEW_BB to use. */
3886 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3888 gimple ophi
= gsi_stmt (ogsi
);
3889 tree oresult
= gimple_phi_result (ophi
);
3890 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
3894 /* At this point we know that the merge will succeed. Remove the PHI
3895 nodes for the virtuals that we want to rename. */
3896 if (!bitmap_empty_p (rename_virts
))
3898 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); )
3900 gimple nphi
= gsi_stmt (ngsi
);
3901 tree nresult
= gimple_phi_result (nphi
);
3902 if (bitmap_bit_p (rename_virts
, SSA_NAME_VERSION (nresult
)))
3904 mark_virtual_phi_result_for_renaming (nphi
);
3905 remove_phi_node (&ngsi
, true);
3912 /* Finally, move the edges and update the PHIs. */
3913 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
3914 if (e
->flags
& EDGE_EH
)
3916 redirect_eh_edge_1 (e
, new_bb
, change_region
);
3917 redirect_edge_succ (e
, new_bb
);
3918 flush_pending_stmts (e
);
3923 BITMAP_FREE (ophi_handled
);
3924 BITMAP_FREE (rename_virts
);
3928 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3929 redirect_edge_var_map_clear (e
);
3930 BITMAP_FREE (ophi_handled
);
3931 BITMAP_FREE (rename_virts
);
3935 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
3936 old region to NEW_REGION at BB. */
3939 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
3940 eh_landing_pad lp
, eh_region new_region
)
3942 gimple_stmt_iterator gsi
;
3945 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
3949 lp
->region
= new_region
;
3950 lp
->next_lp
= new_region
->landing_pads
;
3951 new_region
->landing_pads
= lp
;
3953 /* Delete the RESX that was matched within the empty handler block. */
3954 gsi
= gsi_last_bb (bb
);
3955 mark_virtual_ops_for_renaming (gsi_stmt (gsi
));
3956 gsi_remove (&gsi
, true);
3958 /* Clean up E_OUT for the fallthru. */
3959 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3960 e_out
->probability
= REG_BR_PROB_BASE
;
3963 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
3964 unsplitting than unsplit_eh was prepared to handle, e.g. when
3965 multiple incoming edges and phis are involved. */
3968 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
3970 gimple_stmt_iterator gsi
;
3973 /* We really ought not have totally lost everything following
3974 a landing pad label. Given that BB is empty, there had better
3976 gcc_assert (e_out
!= NULL
);
3978 /* The destination block must not already have a landing pad
3979 for a different region. */
3981 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3983 gimple stmt
= gsi_stmt (gsi
);
3986 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3988 lab
= gimple_label_label (stmt
);
3989 lp_nr
= EH_LANDING_PAD_NR (lab
);
3990 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3994 /* Attempt to move the PHIs into the successor block. */
3995 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
3997 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3999 "Unsplit EH landing pad %d to block %i "
4000 "(via cleanup_empty_eh).\n",
4001 lp
->index
, e_out
->dest
->index
);
4008 /* Return true if edge E_FIRST is part of an empty infinite loop
4009 or leads to such a loop through a series of single successor
4013 infinite_empty_loop_p (edge e_first
)
4015 bool inf_loop
= false;
4018 if (e_first
->dest
== e_first
->src
)
4021 e_first
->src
->aux
= (void *) 1;
4022 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
4024 gimple_stmt_iterator gsi
;
4030 e
->dest
->aux
= (void *) 1;
4031 gsi
= gsi_after_labels (e
->dest
);
4032 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4033 gsi_next_nondebug (&gsi
);
4034 if (!gsi_end_p (gsi
))
4037 e_first
->src
->aux
= NULL
;
4038 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
4039 e
->dest
->aux
= NULL
;
4044 /* Examine the block associated with LP to determine if it's an empty
4045 handler for its EH region. If so, attempt to redirect EH edges to
4046 an outer region. Return true the CFG was updated in any way. This
4047 is similar to jump forwarding, just across EH edges. */
4050 cleanup_empty_eh (eh_landing_pad lp
)
4052 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4053 gimple_stmt_iterator gsi
;
4055 eh_region new_region
;
4058 bool has_non_eh_pred
;
4062 /* There can be zero or one edges out of BB. This is the quickest test. */
4063 switch (EDGE_COUNT (bb
->succs
))
4069 e_out
= EDGE_SUCC (bb
, 0);
4075 resx
= last_stmt (bb
);
4076 if (resx
&& is_gimple_resx (resx
))
4078 if (stmt_can_throw_external (resx
))
4079 optimize_clobbers (bb
);
4080 else if (sink_clobbers (bb
))
4084 gsi
= gsi_after_labels (bb
);
4086 /* Make sure to skip debug statements. */
4087 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4088 gsi_next_nondebug (&gsi
);
4090 /* If the block is totally empty, look for more unsplitting cases. */
4091 if (gsi_end_p (gsi
))
4093 /* For the degenerate case of an infinite loop bail out. */
4094 if (infinite_empty_loop_p (e_out
))
4097 return ret
| cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
4100 /* The block should consist only of a single RESX statement, modulo a
4101 preceding call to __builtin_stack_restore if there is no outgoing
4102 edge, since the call can be eliminated in this case. */
4103 resx
= gsi_stmt (gsi
);
4104 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
4107 resx
= gsi_stmt (gsi
);
4109 if (!is_gimple_resx (resx
))
4111 gcc_assert (gsi_one_before_end_p (gsi
));
4113 /* Determine if there are non-EH edges, or resx edges into the handler. */
4114 has_non_eh_pred
= false;
4115 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4116 if (!(e
->flags
& EDGE_EH
))
4117 has_non_eh_pred
= true;
4119 /* Find the handler that's outer of the empty handler by looking at
4120 where the RESX instruction was vectored. */
4121 new_lp_nr
= lookup_stmt_eh_lp (resx
);
4122 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
4124 /* If there's no destination region within the current function,
4125 redirection is trivial via removing the throwing statements from
4126 the EH region, removing the EH edges, and allowing the block
4127 to go unreachable. */
4128 if (new_region
== NULL
)
4130 gcc_assert (e_out
== NULL
);
4131 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4132 if (e
->flags
& EDGE_EH
)
4134 gimple stmt
= last_stmt (e
->src
);
4135 remove_stmt_from_eh_lp (stmt
);
4143 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4144 to handle the abort and allow the blocks to go unreachable. */
4145 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4147 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4148 if (e
->flags
& EDGE_EH
)
4150 gimple stmt
= last_stmt (e
->src
);
4151 remove_stmt_from_eh_lp (stmt
);
4152 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4160 /* Try to redirect the EH edges and merge the PHIs into the destination
4161 landing pad block. If the merge succeeds, we'll already have redirected
4162 all the EH edges. The handler itself will go unreachable if there were
4164 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4167 /* Finally, if all input edges are EH edges, then we can (potentially)
4168 reduce the number of transfers from the runtime by moving the landing
4169 pad from the original region to the new region. This is a win when
4170 we remove the last CLEANUP region along a particular exception
4171 propagation path. Since nothing changes except for the region with
4172 which the landing pad is associated, the PHI nodes do not need to be
4174 if (!has_non_eh_pred
)
4176 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4177 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4178 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4179 lp
->index
, new_region
->index
);
4181 /* ??? The CFG didn't change, but we may have rendered the
4182 old EH region unreachable. Trigger a cleanup there. */
4189 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4190 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4191 remove_eh_landing_pad (lp
);
4195 /* Do a post-order traversal of the EH region tree. Examine each
4196 post_landing_pad block and see if we can eliminate it as empty. */
4199 cleanup_all_empty_eh (void)
4201 bool changed
= false;
4205 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
4207 changed
|= cleanup_empty_eh (lp
);
4212 /* Perform cleanups and lowering of exception handling
4213 1) cleanups regions with handlers doing nothing are optimized out
4214 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4215 3) Info about regions that are containing instructions, and regions
4216 reachable via local EH edges is collected
4217 4) Eh tree is pruned for regions no longer neccesary.
4219 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4220 Unify those that have the same failure decl and locus.
4224 execute_cleanup_eh_1 (void)
4226 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4227 looking up unreachable landing pads. */
4228 remove_unreachable_handlers ();
4230 /* Watch out for the region tree vanishing due to all unreachable. */
4231 if (cfun
->eh
->region_tree
&& optimize
)
4233 bool changed
= false;
4235 changed
|= unsplit_all_eh ();
4236 changed
|= cleanup_all_empty_eh ();
4240 free_dominance_info (CDI_DOMINATORS
);
4241 free_dominance_info (CDI_POST_DOMINATORS
);
4243 /* We delayed all basic block deletion, as we may have performed
4244 cleanups on EH edges while non-EH edges were still present. */
4245 delete_unreachable_blocks ();
4247 /* We manipulated the landing pads. Remove any region that no
4248 longer has a landing pad. */
4249 remove_unreachable_handlers_no_lp ();
4251 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4259 execute_cleanup_eh (void)
4261 int ret
= execute_cleanup_eh_1 ();
4263 /* If the function no longer needs an EH personality routine
4264 clear it. This exposes cross-language inlining opportunities
4265 and avoids references to a never defined personality routine. */
4266 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4267 && function_needs_eh_personality (cfun
) != eh_personality_lang
)
4268 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4274 gate_cleanup_eh (void)
4276 return cfun
->eh
!= NULL
&& cfun
->eh
->region_tree
!= NULL
;
4279 struct gimple_opt_pass pass_cleanup_eh
= {
4282 "ehcleanup", /* name */
4283 gate_cleanup_eh
, /* gate */
4284 execute_cleanup_eh
, /* execute */
4287 0, /* static_pass_number */
4288 TV_TREE_EH
, /* tv_id */
4289 PROP_gimple_lcf
, /* properties_required */
4290 0, /* properties_provided */
4291 0, /* properties_destroyed */
4292 0, /* todo_flags_start */
4293 0 /* todo_flags_finish */
4297 /* Verify that BB containing STMT as the last statement, has precisely the
4298 edge that make_eh_edges would create. */
4301 verify_eh_edges (gimple stmt
)
4303 basic_block bb
= gimple_bb (stmt
);
4304 eh_landing_pad lp
= NULL
;
4309 lp_nr
= lookup_stmt_eh_lp (stmt
);
4311 lp
= get_eh_landing_pad_from_number (lp_nr
);
4314 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4316 if (e
->flags
& EDGE_EH
)
4320 error ("BB %i has multiple EH edges", bb
->index
);
4332 error ("BB %i can not throw but has an EH edge", bb
->index
);
4338 if (!stmt_could_throw_p (stmt
))
4340 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4344 if (eh_edge
== NULL
)
4346 error ("BB %i is missing an EH edge", bb
->index
);
4350 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
4352 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4359 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4362 verify_eh_dispatch_edge (gimple stmt
)
4366 basic_block src
, dst
;
4367 bool want_fallthru
= true;
4371 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4372 src
= gimple_bb (stmt
);
4374 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4375 gcc_assert (e
->aux
== NULL
);
4380 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4382 dst
= label_to_block (c
->label
);
4383 e
= find_edge (src
, dst
);
4386 error ("BB %i is missing an edge", src
->index
);
4391 /* A catch-all handler doesn't have a fallthru. */
4392 if (c
->type_list
== NULL
)
4394 want_fallthru
= false;
4400 case ERT_ALLOWED_EXCEPTIONS
:
4401 dst
= label_to_block (r
->u
.allowed
.label
);
4402 e
= find_edge (src
, dst
);
4405 error ("BB %i is missing an edge", src
->index
);
4416 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4418 if (e
->flags
& EDGE_FALLTHRU
)
4420 if (fall_edge
!= NULL
)
4422 error ("BB %i too many fallthru edges", src
->index
);
4431 error ("BB %i has incorrect edge", src
->index
);
4435 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4437 error ("BB %i has incorrect fallthru edge", src
->index
);