1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
23 #include "hash-table.h"
31 #include "pointer-set.h"
32 #include "basic-block.h"
33 #include "tree-ssa-alias.h"
34 #include "internal-fn.h"
36 #include "gimple-expr.h"
39 #include "gimple-iterator.h"
40 #include "gimple-ssa.h"
43 #include "tree-phinodes.h"
44 #include "ssa-iterators.h"
45 #include "stringpool.h"
46 #include "tree-ssanames.h"
47 #include "tree-into-ssa.h"
49 #include "tree-inline.h"
50 #include "tree-pass.h"
51 #include "langhooks.h"
52 #include "diagnostic-core.h"
55 #include "gimple-low.h"
57 /* In some instances a tree and a gimple need to be stored in a same table,
58 i.e. in hash tables. This is a structure to do this. */
59 typedef union {tree
*tp
; tree t
; gimple g
;} treemple
;
61 /* Misc functions used in this file. */
63 /* Remember and lookup EH landing pad data for arbitrary statements.
64 Really this means any statement that could_throw_p. We could
65 stuff this information into the stmt_ann data structure, but:
67 (1) We absolutely rely on this information being kept until
68 we get to rtl. Once we're done with lowering here, if we lose
69 the information there's no way to recover it!
71 (2) There are many more statements that *cannot* throw as
72 compared to those that can. We should be saving some amount
73 of space by only allocating memory for those that can throw. */
75 /* Add statement T in function IFUN to landing pad NUM. */
78 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple t
, int num
)
80 struct throw_stmt_node
*n
;
83 gcc_assert (num
!= 0);
85 n
= ggc_alloc_throw_stmt_node ();
89 if (!get_eh_throw_stmt_table (ifun
))
90 set_eh_throw_stmt_table (ifun
, htab_create_ggc (31, struct_ptr_hash
,
94 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), n
, INSERT
);
99 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
102 add_stmt_to_eh_lp (gimple t
, int num
)
104 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
107 /* Add statement T to the single EH landing pad in REGION. */
110 record_stmt_eh_region (eh_region region
, gimple t
)
114 if (region
->type
== ERT_MUST_NOT_THROW
)
115 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
118 eh_landing_pad lp
= region
->landing_pads
;
120 lp
= gen_eh_landing_pad (region
);
122 gcc_assert (lp
->next_lp
== NULL
);
123 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
128 /* Remove statement T in function IFUN from its EH landing pad. */
131 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple t
)
133 struct throw_stmt_node dummy
;
136 if (!get_eh_throw_stmt_table (ifun
))
140 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), &dummy
,
144 htab_clear_slot (get_eh_throw_stmt_table (ifun
), slot
);
152 /* Remove statement T in the current function (cfun) from its
156 remove_stmt_from_eh_lp (gimple t
)
158 return remove_stmt_from_eh_lp_fn (cfun
, t
);
161 /* Determine if statement T is inside an EH region in function IFUN.
162 Positive numbers indicate a landing pad index; negative numbers
163 indicate a MUST_NOT_THROW region index; zero indicates that the
164 statement is not recorded in the region table. */
167 lookup_stmt_eh_lp_fn (struct function
*ifun
, gimple t
)
169 struct throw_stmt_node
*p
, n
;
171 if (ifun
->eh
->throw_stmt_table
== NULL
)
175 p
= (struct throw_stmt_node
*) htab_find (ifun
->eh
->throw_stmt_table
, &n
);
176 return p
? p
->lp_nr
: 0;
179 /* Likewise, but always use the current function. */
182 lookup_stmt_eh_lp (gimple t
)
184 /* We can get called from initialized data when -fnon-call-exceptions
185 is on; prevent crash. */
188 return lookup_stmt_eh_lp_fn (cfun
, t
);
191 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
192 nodes and LABEL_DECL nodes. We will use this during the second phase to
193 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
195 struct finally_tree_node
197 /* When storing a GIMPLE_TRY, we have to record a gimple. However
198 when deciding whether a GOTO to a certain LABEL_DECL (which is a
199 tree) leaves the TRY block, its necessary to record a tree in
200 this field. Thus a treemple is used. */
205 /* Hashtable helpers. */
207 struct finally_tree_hasher
: typed_free_remove
<finally_tree_node
>
209 typedef finally_tree_node value_type
;
210 typedef finally_tree_node compare_type
;
211 static inline hashval_t
hash (const value_type
*);
212 static inline bool equal (const value_type
*, const compare_type
*);
216 finally_tree_hasher::hash (const value_type
*v
)
218 return (intptr_t)v
->child
.t
>> 4;
222 finally_tree_hasher::equal (const value_type
*v
, const compare_type
*c
)
224 return v
->child
.t
== c
->child
.t
;
227 /* Note that this table is *not* marked GTY. It is short-lived. */
228 static hash_table
<finally_tree_hasher
> finally_tree
;
231 record_in_finally_tree (treemple child
, gimple parent
)
233 struct finally_tree_node
*n
;
234 finally_tree_node
**slot
;
236 n
= XNEW (struct finally_tree_node
);
240 slot
= finally_tree
.find_slot (n
, INSERT
);
246 collect_finally_tree (gimple stmt
, gimple region
);
248 /* Go through the gimple sequence. Works with collect_finally_tree to
249 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
252 collect_finally_tree_1 (gimple_seq seq
, gimple region
)
254 gimple_stmt_iterator gsi
;
256 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
257 collect_finally_tree (gsi_stmt (gsi
), region
);
261 collect_finally_tree (gimple stmt
, gimple region
)
265 switch (gimple_code (stmt
))
268 temp
.t
= gimple_label_label (stmt
);
269 record_in_finally_tree (temp
, region
);
273 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
276 record_in_finally_tree (temp
, region
);
277 collect_finally_tree_1 (gimple_try_eval (stmt
), stmt
);
278 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
280 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
282 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
283 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
288 collect_finally_tree_1 (gimple_catch_handler (stmt
), region
);
291 case GIMPLE_EH_FILTER
:
292 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
296 collect_finally_tree_1 (gimple_eh_else_n_body (stmt
), region
);
297 collect_finally_tree_1 (gimple_eh_else_e_body (stmt
), region
);
301 /* A type, a decl, or some kind of statement that we're not
302 interested in. Don't walk them. */
308 /* Use the finally tree to determine if a jump from START to TARGET
309 would leave the try_finally node that START lives in. */
312 outside_finally_tree (treemple start
, gimple target
)
314 struct finally_tree_node n
, *p
;
319 p
= finally_tree
.find (&n
);
324 while (start
.g
!= target
);
329 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
330 nodes into a set of gotos, magic labels, and eh regions.
331 The eh region creation is straight-forward, but frobbing all the gotos
332 and such into shape isn't. */
334 /* The sequence into which we record all EH stuff. This will be
335 placed at the end of the function when we're all done. */
336 static gimple_seq eh_seq
;
338 /* Record whether an EH region contains something that can throw,
339 indexed by EH region number. */
340 static bitmap eh_region_may_contain_throw_map
;
342 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
343 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
344 The idea is to record a gimple statement for everything except for
345 the conditionals, which get their labels recorded. Since labels are
346 of type 'tree', we need this node to store both gimple and tree
347 objects. REPL_STMT is the sequence used to replace the goto/return
348 statement. CONT_STMT is used to store the statement that allows
349 the return/goto to jump to the original destination. */
351 struct goto_queue_node
355 gimple_seq repl_stmt
;
358 /* This is used when index >= 0 to indicate that stmt is a label (as
359 opposed to a goto stmt). */
363 /* State of the world while lowering. */
367 /* What's "current" while constructing the eh region tree. These
368 correspond to variables of the same name in cfun->eh, which we
369 don't have easy access to. */
370 eh_region cur_region
;
372 /* What's "current" for the purposes of __builtin_eh_pointer. For
373 a CATCH, this is the associated TRY. For an EH_FILTER, this is
374 the associated ALLOWED_EXCEPTIONS, etc. */
375 eh_region ehp_region
;
377 /* Processing of TRY_FINALLY requires a bit more state. This is
378 split out into a separate structure so that we don't have to
379 copy so much when processing other nodes. */
380 struct leh_tf_state
*tf
;
385 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
386 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
387 this so that outside_finally_tree can reliably reference the tree used
388 in the collect_finally_tree data structures. */
389 gimple try_finally_expr
;
392 /* While lowering a top_p usually it is expanded into multiple statements,
393 thus we need the following field to store them. */
394 gimple_seq top_p_seq
;
396 /* The state outside this try_finally node. */
397 struct leh_state
*outer
;
399 /* The exception region created for it. */
402 /* The goto queue. */
403 struct goto_queue_node
*goto_queue
;
404 size_t goto_queue_size
;
405 size_t goto_queue_active
;
407 /* Pointer map to help in searching goto_queue when it is large. */
408 struct pointer_map_t
*goto_queue_map
;
410 /* The set of unique labels seen as entries in the goto queue. */
411 vec
<tree
> dest_array
;
413 /* A label to be added at the end of the completed transformed
414 sequence. It will be set if may_fallthru was true *at one time*,
415 though subsequent transformations may have cleared that flag. */
418 /* True if it is possible to fall out the bottom of the try block.
419 Cleared if the fallthru is converted to a goto. */
422 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
425 /* True if the finally block can receive an exception edge.
426 Cleared if the exception case is handled by code duplication. */
430 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gimple
);
432 /* Search for STMT in the goto queue. Return the replacement,
433 or null if the statement isn't in the queue. */
435 #define LARGE_GOTO_QUEUE 20
437 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*seq
);
440 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
445 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
447 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
448 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
449 return tf
->goto_queue
[i
].repl_stmt
;
453 /* If we have a large number of entries in the goto_queue, create a
454 pointer map and use that for searching. */
456 if (!tf
->goto_queue_map
)
458 tf
->goto_queue_map
= pointer_map_create ();
459 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
461 slot
= pointer_map_insert (tf
->goto_queue_map
,
462 tf
->goto_queue
[i
].stmt
.g
);
463 gcc_assert (*slot
== NULL
);
464 *slot
= &tf
->goto_queue
[i
];
468 slot
= pointer_map_contains (tf
->goto_queue_map
, stmt
.g
);
470 return (((struct goto_queue_node
*) *slot
)->repl_stmt
);
475 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
476 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
477 then we can just splat it in, otherwise we add the new stmts immediately
478 after the GIMPLE_COND and redirect. */
481 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
482 gimple_stmt_iterator
*gsi
)
487 location_t loc
= gimple_location (gsi_stmt (*gsi
));
490 new_seq
= find_goto_replacement (tf
, temp
);
494 if (gimple_seq_singleton_p (new_seq
)
495 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
497 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
501 label
= create_artificial_label (loc
);
502 /* Set the new label for the GIMPLE_COND */
505 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
506 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
509 /* The real work of replace_goto_queue. Returns with TSI updated to
510 point to the next statement. */
512 static void replace_goto_queue_stmt_list (gimple_seq
*, struct leh_tf_state
*);
515 replace_goto_queue_1 (gimple stmt
, struct leh_tf_state
*tf
,
516 gimple_stmt_iterator
*gsi
)
522 switch (gimple_code (stmt
))
527 seq
= find_goto_replacement (tf
, temp
);
530 gsi_insert_seq_before (gsi
, gimple_seq_copy (seq
), GSI_SAME_STMT
);
531 gsi_remove (gsi
, false);
537 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
538 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
542 replace_goto_queue_stmt_list (gimple_try_eval_ptr (stmt
), tf
);
543 replace_goto_queue_stmt_list (gimple_try_cleanup_ptr (stmt
), tf
);
546 replace_goto_queue_stmt_list (gimple_catch_handler_ptr (stmt
), tf
);
548 case GIMPLE_EH_FILTER
:
549 replace_goto_queue_stmt_list (gimple_eh_filter_failure_ptr (stmt
), tf
);
552 replace_goto_queue_stmt_list (gimple_eh_else_n_body_ptr (stmt
), tf
);
553 replace_goto_queue_stmt_list (gimple_eh_else_e_body_ptr (stmt
), tf
);
557 /* These won't have gotos in them. */
564 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
567 replace_goto_queue_stmt_list (gimple_seq
*seq
, struct leh_tf_state
*tf
)
569 gimple_stmt_iterator gsi
= gsi_start (*seq
);
571 while (!gsi_end_p (gsi
))
572 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
575 /* Replace all goto queue members. */
578 replace_goto_queue (struct leh_tf_state
*tf
)
580 if (tf
->goto_queue_active
== 0)
582 replace_goto_queue_stmt_list (&tf
->top_p_seq
, tf
);
583 replace_goto_queue_stmt_list (&eh_seq
, tf
);
586 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
587 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
591 record_in_goto_queue (struct leh_tf_state
*tf
,
598 struct goto_queue_node
*q
;
600 gcc_assert (!tf
->goto_queue_map
);
602 active
= tf
->goto_queue_active
;
603 size
= tf
->goto_queue_size
;
606 size
= (size
? size
* 2 : 32);
607 tf
->goto_queue_size
= size
;
609 = XRESIZEVEC (struct goto_queue_node
, tf
->goto_queue
, size
);
612 q
= &tf
->goto_queue
[active
];
613 tf
->goto_queue_active
= active
+ 1;
615 memset (q
, 0, sizeof (*q
));
618 q
->location
= location
;
619 q
->is_label
= is_label
;
622 /* Record the LABEL label in the goto queue contained in TF.
626 record_in_goto_queue_label (struct leh_tf_state
*tf
, treemple stmt
, tree label
,
630 treemple temp
, new_stmt
;
635 /* Computed and non-local gotos do not get processed. Given
636 their nature we can neither tell whether we've escaped the
637 finally block nor redirect them if we knew. */
638 if (TREE_CODE (label
) != LABEL_DECL
)
641 /* No need to record gotos that don't leave the try block. */
643 if (!outside_finally_tree (temp
, tf
->try_finally_expr
))
646 if (! tf
->dest_array
.exists ())
648 tf
->dest_array
.create (10);
649 tf
->dest_array
.quick_push (label
);
654 int n
= tf
->dest_array
.length ();
655 for (index
= 0; index
< n
; ++index
)
656 if (tf
->dest_array
[index
] == label
)
659 tf
->dest_array
.safe_push (label
);
662 /* In the case of a GOTO we want to record the destination label,
663 since with a GIMPLE_COND we have an easy access to the then/else
666 record_in_goto_queue (tf
, new_stmt
, index
, true, location
);
669 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
670 node, and if so record that fact in the goto queue associated with that
674 maybe_record_in_goto_queue (struct leh_state
*state
, gimple stmt
)
676 struct leh_tf_state
*tf
= state
->tf
;
682 switch (gimple_code (stmt
))
685 new_stmt
.tp
= gimple_op_ptr (stmt
, 2);
686 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_true_label (stmt
),
687 EXPR_LOCATION (*new_stmt
.tp
));
688 new_stmt
.tp
= gimple_op_ptr (stmt
, 3);
689 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_false_label (stmt
),
690 EXPR_LOCATION (*new_stmt
.tp
));
694 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
),
695 gimple_location (stmt
));
699 tf
->may_return
= true;
701 record_in_goto_queue (tf
, new_stmt
, -1, false, gimple_location (stmt
));
710 #ifdef ENABLE_CHECKING
711 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
712 was in fact structured, and we've not yet done jump threading, then none
713 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
716 verify_norecord_switch_expr (struct leh_state
*state
, gimple switch_expr
)
718 struct leh_tf_state
*tf
= state
->tf
;
724 n
= gimple_switch_num_labels (switch_expr
);
726 for (i
= 0; i
< n
; ++i
)
729 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
731 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
735 #define verify_norecord_switch_expr(state, switch_expr)
738 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
739 non-null, insert it before the new branch. */
742 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
)
746 /* In the case of a return, the queue node must be a gimple statement. */
747 gcc_assert (!q
->is_label
);
749 /* Note that the return value may have already been computed, e.g.,
762 should return 0, not 1. We don't have to do anything to make
763 this happens because the return value has been placed in the
764 RESULT_DECL already. */
766 q
->cont_stmt
= q
->stmt
.g
;
769 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
771 x
= gimple_build_goto (finlab
);
772 gimple_set_location (x
, q
->location
);
773 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
776 /* Similar, but easier, for GIMPLE_GOTO. */
779 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
780 struct leh_tf_state
*tf
)
784 gcc_assert (q
->is_label
);
786 q
->cont_stmt
= gimple_build_goto (tf
->dest_array
[q
->index
]);
789 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
791 x
= gimple_build_goto (finlab
);
792 gimple_set_location (x
, q
->location
);
793 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
796 /* Emit a standard landing pad sequence into SEQ for REGION. */
799 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
801 eh_landing_pad lp
= region
->landing_pads
;
805 lp
= gen_eh_landing_pad (region
);
807 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
808 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
810 x
= gimple_build_label (lp
->post_landing_pad
);
811 gimple_seq_add_stmt (seq
, x
);
814 /* Emit a RESX statement into SEQ for REGION. */
817 emit_resx (gimple_seq
*seq
, eh_region region
)
819 gimple x
= gimple_build_resx (region
->index
);
820 gimple_seq_add_stmt (seq
, x
);
822 record_stmt_eh_region (region
->outer
, x
);
825 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
828 emit_eh_dispatch (gimple_seq
*seq
, eh_region region
)
830 gimple x
= gimple_build_eh_dispatch (region
->index
);
831 gimple_seq_add_stmt (seq
, x
);
834 /* Note that the current EH region may contain a throw, or a
835 call to a function which itself may contain a throw. */
838 note_eh_region_may_contain_throw (eh_region region
)
840 while (bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
))
842 if (region
->type
== ERT_MUST_NOT_THROW
)
844 region
= region
->outer
;
850 /* Check if REGION has been marked as containing a throw. If REGION is
851 NULL, this predicate is false. */
854 eh_region_may_contain_throw (eh_region r
)
856 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
859 /* We want to transform
860 try { body; } catch { stuff; }
870 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
871 should be placed before the second operand, or NULL. OVER is
872 an existing label that should be put at the exit, or NULL. */
875 frob_into_branch_around (gimple tp
, eh_region region
, tree over
)
878 gimple_seq cleanup
, result
;
879 location_t loc
= gimple_location (tp
);
881 cleanup
= gimple_try_cleanup (tp
);
882 result
= gimple_try_eval (tp
);
885 emit_post_landing_pad (&eh_seq
, region
);
887 if (gimple_seq_may_fallthru (cleanup
))
890 over
= create_artificial_label (loc
);
891 x
= gimple_build_goto (over
);
892 gimple_set_location (x
, loc
);
893 gimple_seq_add_stmt (&cleanup
, x
);
895 gimple_seq_add_seq (&eh_seq
, cleanup
);
899 x
= gimple_build_label (over
);
900 gimple_seq_add_stmt (&result
, x
);
905 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
906 Make sure to record all new labels found. */
909 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
,
912 gimple region
= NULL
;
914 gimple_stmt_iterator gsi
;
916 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
918 for (gsi
= gsi_start (new_seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
920 gimple stmt
= gsi_stmt (gsi
);
921 if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
923 tree block
= gimple_block (stmt
);
924 gimple_set_location (stmt
, loc
);
925 gimple_set_block (stmt
, block
);
930 region
= outer_state
->tf
->try_finally_expr
;
931 collect_finally_tree_1 (new_seq
, region
);
936 /* A subroutine of lower_try_finally. Create a fallthru label for
937 the given try_finally state. The only tricky bit here is that
938 we have to make sure to record the label in our outer context. */
941 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
943 tree label
= tf
->fallthru_label
;
948 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
949 tf
->fallthru_label
= label
;
953 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
959 /* A subroutine of lower_try_finally. If FINALLY consits of a
960 GIMPLE_EH_ELSE node, return it. */
963 get_eh_else (gimple_seq finally
)
965 gimple x
= gimple_seq_first_stmt (finally
);
966 if (gimple_code (x
) == GIMPLE_EH_ELSE
)
968 gcc_assert (gimple_seq_singleton_p (finally
));
974 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
975 langhook returns non-null, then the language requires that the exception
976 path out of a try_finally be treated specially. To wit: the code within
977 the finally block may not itself throw an exception. We have two choices
978 here. First we can duplicate the finally block and wrap it in a
979 must_not_throw region. Second, we can generate code like
984 if (fintmp == eh_edge)
985 protect_cleanup_actions;
988 where "fintmp" is the temporary used in the switch statement generation
989 alternative considered below. For the nonce, we always choose the first
992 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
995 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
996 struct leh_state
*this_state
,
997 struct leh_tf_state
*tf
)
999 tree protect_cleanup_actions
;
1000 gimple_stmt_iterator gsi
;
1001 bool finally_may_fallthru
;
1005 /* First check for nothing to do. */
1006 if (lang_hooks
.eh_protect_cleanup_actions
== NULL
)
1008 protect_cleanup_actions
= lang_hooks
.eh_protect_cleanup_actions ();
1009 if (protect_cleanup_actions
== NULL
)
1012 finally
= gimple_try_cleanup (tf
->top_p
);
1013 eh_else
= get_eh_else (finally
);
1015 /* Duplicate the FINALLY block. Only need to do this for try-finally,
1016 and not for cleanups. If we've got an EH_ELSE, extract it now. */
1019 finally
= gimple_eh_else_e_body (eh_else
);
1020 gimple_try_set_cleanup (tf
->top_p
, gimple_eh_else_n_body (eh_else
));
1022 else if (this_state
)
1023 finally
= lower_try_finally_dup_block (finally
, outer_state
,
1024 gimple_location (tf
->try_finally_expr
));
1025 finally_may_fallthru
= gimple_seq_may_fallthru (finally
);
1027 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1028 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1029 to be in an enclosing scope, but needs to be implemented at this level
1030 to avoid a nesting violation (see wrap_temporary_cleanups in
1031 cp/decl.c). Since it's logically at an outer level, we should call
1032 terminate before we get to it, so strip it away before adding the
1033 MUST_NOT_THROW filter. */
1034 gsi
= gsi_start (finally
);
1036 if (gimple_code (x
) == GIMPLE_TRY
1037 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
1038 && gimple_try_catch_is_cleanup (x
))
1040 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
1041 gsi_remove (&gsi
, false);
1044 /* Wrap the block with protect_cleanup_actions as the action. */
1045 x
= gimple_build_eh_must_not_throw (protect_cleanup_actions
);
1046 x
= gimple_build_try (finally
, gimple_seq_alloc_with_stmt (x
),
1048 finally
= lower_eh_must_not_throw (outer_state
, x
);
1050 /* Drop all of this into the exception sequence. */
1051 emit_post_landing_pad (&eh_seq
, tf
->region
);
1052 gimple_seq_add_seq (&eh_seq
, finally
);
1053 if (finally_may_fallthru
)
1054 emit_resx (&eh_seq
, tf
->region
);
1056 /* Having now been handled, EH isn't to be considered with
1057 the rest of the outgoing edges. */
1058 tf
->may_throw
= false;
1061 /* A subroutine of lower_try_finally. We have determined that there is
1062 no fallthru edge out of the finally block. This means that there is
1063 no outgoing edge corresponding to any incoming edge. Restructure the
1064 try_finally node for this special case. */
1067 lower_try_finally_nofallthru (struct leh_state
*state
,
1068 struct leh_tf_state
*tf
)
1073 struct goto_queue_node
*q
, *qe
;
1075 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1077 /* We expect that tf->top_p is a GIMPLE_TRY. */
1078 finally
= gimple_try_cleanup (tf
->top_p
);
1079 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1081 x
= gimple_build_label (lab
);
1082 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1085 qe
= q
+ tf
->goto_queue_active
;
1088 do_return_redirection (q
, lab
, NULL
);
1090 do_goto_redirection (q
, lab
, NULL
, tf
);
1092 replace_goto_queue (tf
);
1094 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1095 eh_else
= get_eh_else (finally
);
1098 finally
= gimple_eh_else_n_body (eh_else
);
1099 lower_eh_constructs_1 (state
, &finally
);
1100 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1104 finally
= gimple_eh_else_e_body (eh_else
);
1105 lower_eh_constructs_1 (state
, &finally
);
1107 emit_post_landing_pad (&eh_seq
, tf
->region
);
1108 gimple_seq_add_seq (&eh_seq
, finally
);
1113 lower_eh_constructs_1 (state
, &finally
);
1114 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1118 emit_post_landing_pad (&eh_seq
, tf
->region
);
1120 x
= gimple_build_goto (lab
);
1121 gimple_set_location (x
, gimple_location (tf
->try_finally_expr
));
1122 gimple_seq_add_stmt (&eh_seq
, x
);
1127 /* A subroutine of lower_try_finally. We have determined that there is
1128 exactly one destination of the finally block. Restructure the
1129 try_finally node for this special case. */
1132 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1134 struct goto_queue_node
*q
, *qe
;
1137 gimple_stmt_iterator gsi
;
1139 location_t loc
= gimple_location (tf
->try_finally_expr
);
1141 finally
= gimple_try_cleanup (tf
->top_p
);
1142 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1144 /* Since there's only one destination, and the destination edge can only
1145 either be EH or non-EH, that implies that all of our incoming edges
1146 are of the same type. Therefore we can lower EH_ELSE immediately. */
1147 x
= get_eh_else (finally
);
1151 finally
= gimple_eh_else_e_body (x
);
1153 finally
= gimple_eh_else_n_body (x
);
1156 lower_eh_constructs_1 (state
, &finally
);
1158 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1160 gimple stmt
= gsi_stmt (gsi
);
1161 if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
1163 tree block
= gimple_block (stmt
);
1164 gimple_set_location (stmt
, gimple_location (tf
->try_finally_expr
));
1165 gimple_set_block (stmt
, block
);
1171 /* Only reachable via the exception edge. Add the given label to
1172 the head of the FINALLY block. Append a RESX at the end. */
1173 emit_post_landing_pad (&eh_seq
, tf
->region
);
1174 gimple_seq_add_seq (&eh_seq
, finally
);
1175 emit_resx (&eh_seq
, tf
->region
);
1179 if (tf
->may_fallthru
)
1181 /* Only reachable via the fallthru edge. Do nothing but let
1182 the two blocks run together; we'll fall out the bottom. */
1183 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1187 finally_label
= create_artificial_label (loc
);
1188 x
= gimple_build_label (finally_label
);
1189 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1191 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1194 qe
= q
+ tf
->goto_queue_active
;
1198 /* Reachable by return expressions only. Redirect them. */
1200 do_return_redirection (q
, finally_label
, NULL
);
1201 replace_goto_queue (tf
);
1205 /* Reachable by goto expressions only. Redirect them. */
1207 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1208 replace_goto_queue (tf
);
1210 if (tf
->dest_array
[0] == tf
->fallthru_label
)
1212 /* Reachable by goto to fallthru label only. Redirect it
1213 to the new label (already created, sadly), and do not
1214 emit the final branch out, or the fallthru label. */
1215 tf
->fallthru_label
= NULL
;
1220 /* Place the original return/goto to the original destination
1221 immediately after the finally block. */
1222 x
= tf
->goto_queue
[0].cont_stmt
;
1223 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1224 maybe_record_in_goto_queue (state
, x
);
1227 /* A subroutine of lower_try_finally. There are multiple edges incoming
1228 and outgoing from the finally block. Implement this by duplicating the
1229 finally block for every destination. */
1232 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1235 gimple_seq new_stmt
;
1239 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1241 finally
= gimple_try_cleanup (tf
->top_p
);
1243 /* Notice EH_ELSE, and simplify some of the remaining code
1244 by considering FINALLY to be the normal return path only. */
1245 eh_else
= get_eh_else (finally
);
1247 finally
= gimple_eh_else_n_body (eh_else
);
1249 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1252 if (tf
->may_fallthru
)
1254 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1255 lower_eh_constructs_1 (state
, &seq
);
1256 gimple_seq_add_seq (&new_stmt
, seq
);
1258 tmp
= lower_try_finally_fallthru_label (tf
);
1259 x
= gimple_build_goto (tmp
);
1260 gimple_set_location (x
, tf_loc
);
1261 gimple_seq_add_stmt (&new_stmt
, x
);
1266 /* We don't need to copy the EH path of EH_ELSE,
1267 since it is only emitted once. */
1269 seq
= gimple_eh_else_e_body (eh_else
);
1271 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1272 lower_eh_constructs_1 (state
, &seq
);
1274 emit_post_landing_pad (&eh_seq
, tf
->region
);
1275 gimple_seq_add_seq (&eh_seq
, seq
);
1276 emit_resx (&eh_seq
, tf
->region
);
1281 struct goto_queue_node
*q
, *qe
;
1282 int return_index
, index
;
1285 struct goto_queue_node
*q
;
1289 return_index
= tf
->dest_array
.length ();
1290 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1293 qe
= q
+ tf
->goto_queue_active
;
1296 index
= q
->index
< 0 ? return_index
: q
->index
;
1298 if (!labels
[index
].q
)
1299 labels
[index
].q
= q
;
1302 for (index
= 0; index
< return_index
+ 1; index
++)
1306 q
= labels
[index
].q
;
1310 lab
= labels
[index
].label
1311 = create_artificial_label (tf_loc
);
1313 if (index
== return_index
)
1314 do_return_redirection (q
, lab
, NULL
);
1316 do_goto_redirection (q
, lab
, NULL
, tf
);
1318 x
= gimple_build_label (lab
);
1319 gimple_seq_add_stmt (&new_stmt
, x
);
1321 seq
= lower_try_finally_dup_block (finally
, state
, q
->location
);
1322 lower_eh_constructs_1 (state
, &seq
);
1323 gimple_seq_add_seq (&new_stmt
, seq
);
1325 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1326 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1329 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1333 index
= q
->index
< 0 ? return_index
: q
->index
;
1335 if (labels
[index
].q
== q
)
1338 lab
= labels
[index
].label
;
1340 if (index
== return_index
)
1341 do_return_redirection (q
, lab
, NULL
);
1343 do_goto_redirection (q
, lab
, NULL
, tf
);
1346 replace_goto_queue (tf
);
1350 /* Need to link new stmts after running replace_goto_queue due
1351 to not wanting to process the same goto stmts twice. */
1352 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1355 /* A subroutine of lower_try_finally. There are multiple edges incoming
1356 and outgoing from the finally block. Implement this by instrumenting
1357 each incoming edge and creating a switch statement at the end of the
1358 finally block that branches to the appropriate destination. */
1361 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1363 struct goto_queue_node
*q
, *qe
;
1364 tree finally_tmp
, finally_label
;
1365 int return_index
, eh_index
, fallthru_index
;
1366 int nlabels
, ndests
, j
, last_case_index
;
1368 vec
<tree
> case_label_vec
;
1369 gimple_seq switch_body
= NULL
;
1374 struct pointer_map_t
*cont_map
= NULL
;
1375 /* The location of the TRY_FINALLY stmt. */
1376 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1377 /* The location of the finally block. */
1378 location_t finally_loc
;
1380 finally
= gimple_try_cleanup (tf
->top_p
);
1381 eh_else
= get_eh_else (finally
);
1383 /* Mash the TRY block to the head of the chain. */
1384 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1386 /* The location of the finally is either the last stmt in the finally
1387 block or the location of the TRY_FINALLY itself. */
1388 x
= gimple_seq_last_stmt (finally
);
1389 finally_loc
= x
? gimple_location (x
) : tf_loc
;
1391 /* Prepare for switch statement generation. */
1392 nlabels
= tf
->dest_array
.length ();
1393 return_index
= nlabels
;
1394 eh_index
= return_index
+ tf
->may_return
;
1395 fallthru_index
= eh_index
+ (tf
->may_throw
&& !eh_else
);
1396 ndests
= fallthru_index
+ tf
->may_fallthru
;
1398 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1399 finally_label
= create_artificial_label (finally_loc
);
1401 /* We use vec::quick_push on case_label_vec throughout this function,
1402 since we know the size in advance and allocate precisely as muce
1404 case_label_vec
.create (ndests
);
1406 last_case_index
= 0;
1408 /* Begin inserting code for getting to the finally block. Things
1409 are done in this order to correspond to the sequence the code is
1412 if (tf
->may_fallthru
)
1414 x
= gimple_build_assign (finally_tmp
,
1415 build_int_cst (integer_type_node
,
1417 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1419 tmp
= build_int_cst (integer_type_node
, fallthru_index
);
1420 last_case
= build_case_label (tmp
, NULL
,
1421 create_artificial_label (tf_loc
));
1422 case_label_vec
.quick_push (last_case
);
1425 x
= gimple_build_label (CASE_LABEL (last_case
));
1426 gimple_seq_add_stmt (&switch_body
, x
);
1428 tmp
= lower_try_finally_fallthru_label (tf
);
1429 x
= gimple_build_goto (tmp
);
1430 gimple_set_location (x
, tf_loc
);
1431 gimple_seq_add_stmt (&switch_body
, x
);
1434 /* For EH_ELSE, emit the exception path (plus resx) now, then
1435 subsequently we only need consider the normal path. */
1440 finally
= gimple_eh_else_e_body (eh_else
);
1441 lower_eh_constructs_1 (state
, &finally
);
1443 emit_post_landing_pad (&eh_seq
, tf
->region
);
1444 gimple_seq_add_seq (&eh_seq
, finally
);
1445 emit_resx (&eh_seq
, tf
->region
);
1448 finally
= gimple_eh_else_n_body (eh_else
);
1450 else if (tf
->may_throw
)
1452 emit_post_landing_pad (&eh_seq
, tf
->region
);
1454 x
= gimple_build_assign (finally_tmp
,
1455 build_int_cst (integer_type_node
, eh_index
));
1456 gimple_seq_add_stmt (&eh_seq
, x
);
1458 x
= gimple_build_goto (finally_label
);
1459 gimple_set_location (x
, tf_loc
);
1460 gimple_seq_add_stmt (&eh_seq
, x
);
1462 tmp
= build_int_cst (integer_type_node
, eh_index
);
1463 last_case
= build_case_label (tmp
, NULL
,
1464 create_artificial_label (tf_loc
));
1465 case_label_vec
.quick_push (last_case
);
1468 x
= gimple_build_label (CASE_LABEL (last_case
));
1469 gimple_seq_add_stmt (&eh_seq
, x
);
1470 emit_resx (&eh_seq
, tf
->region
);
1473 x
= gimple_build_label (finally_label
);
1474 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1476 lower_eh_constructs_1 (state
, &finally
);
1477 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1479 /* Redirect each incoming goto edge. */
1481 qe
= q
+ tf
->goto_queue_active
;
1482 j
= last_case_index
+ tf
->may_return
;
1483 /* Prepare the assignments to finally_tmp that are executed upon the
1484 entrance through a particular edge. */
1487 gimple_seq mod
= NULL
;
1489 unsigned int case_index
;
1493 x
= gimple_build_assign (finally_tmp
,
1494 build_int_cst (integer_type_node
,
1496 gimple_seq_add_stmt (&mod
, x
);
1497 do_return_redirection (q
, finally_label
, mod
);
1498 switch_id
= return_index
;
1502 x
= gimple_build_assign (finally_tmp
,
1503 build_int_cst (integer_type_node
, q
->index
));
1504 gimple_seq_add_stmt (&mod
, x
);
1505 do_goto_redirection (q
, finally_label
, mod
, tf
);
1506 switch_id
= q
->index
;
1509 case_index
= j
+ q
->index
;
1510 if (case_label_vec
.length () <= case_index
|| !case_label_vec
[case_index
])
1514 tmp
= build_int_cst (integer_type_node
, switch_id
);
1515 case_lab
= build_case_label (tmp
, NULL
,
1516 create_artificial_label (tf_loc
));
1517 /* We store the cont_stmt in the pointer map, so that we can recover
1518 it in the loop below. */
1520 cont_map
= pointer_map_create ();
1521 slot
= pointer_map_insert (cont_map
, case_lab
);
1522 *slot
= q
->cont_stmt
;
1523 case_label_vec
.quick_push (case_lab
);
1526 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1531 last_case
= case_label_vec
[j
];
1533 gcc_assert (last_case
);
1534 gcc_assert (cont_map
);
1536 slot
= pointer_map_contains (cont_map
, last_case
);
1538 cont_stmt
= *(gimple
*) slot
;
1540 x
= gimple_build_label (CASE_LABEL (last_case
));
1541 gimple_seq_add_stmt (&switch_body
, x
);
1542 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1543 maybe_record_in_goto_queue (state
, cont_stmt
);
1546 pointer_map_destroy (cont_map
);
1548 replace_goto_queue (tf
);
1550 /* Make sure that the last case is the default label, as one is required.
1551 Then sort the labels, which is also required in GIMPLE. */
1552 CASE_LOW (last_case
) = NULL
;
1553 sort_case_labels (case_label_vec
);
1555 /* Build the switch statement, setting last_case to be the default
1557 switch_stmt
= gimple_build_switch (finally_tmp
, last_case
,
1559 gimple_set_location (switch_stmt
, finally_loc
);
1561 /* Need to link SWITCH_STMT after running replace_goto_queue
1562 due to not wanting to process the same goto stmts twice. */
1563 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1564 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1567 /* Decide whether or not we are going to duplicate the finally block.
1568 There are several considerations.
1570 First, if this is Java, then the finally block contains code
1571 written by the user. It has line numbers associated with it,
1572 so duplicating the block means it's difficult to set a breakpoint.
1573 Since controlling code generation via -g is verboten, we simply
1574 never duplicate code without optimization.
1576 Second, we'd like to prevent egregious code growth. One way to
1577 do this is to estimate the size of the finally block, multiply
1578 that by the number of copies we'd need to make, and compare against
1579 the estimate of the size of the switch machinery we'd have to add. */
1582 decide_copy_try_finally (int ndests
, bool may_throw
, gimple_seq finally
)
1584 int f_estimate
, sw_estimate
;
1587 /* If there's an EH_ELSE involved, the exception path is separate
1588 and really doesn't come into play for this computation. */
1589 eh_else
= get_eh_else (finally
);
1592 ndests
-= may_throw
;
1593 finally
= gimple_eh_else_n_body (eh_else
);
1598 gimple_stmt_iterator gsi
;
1603 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1605 gimple stmt
= gsi_stmt (gsi
);
1606 if (!is_gimple_debug (stmt
) && !gimple_clobber_p (stmt
))
1612 /* Finally estimate N times, plus N gotos. */
1613 f_estimate
= count_insns_seq (finally
, &eni_size_weights
);
1614 f_estimate
= (f_estimate
+ 1) * ndests
;
1616 /* Switch statement (cost 10), N variable assignments, N gotos. */
1617 sw_estimate
= 10 + 2 * ndests
;
1619 /* Optimize for size clearly wants our best guess. */
1620 if (optimize_function_for_size_p (cfun
))
1621 return f_estimate
< sw_estimate
;
1623 /* ??? These numbers are completely made up so far. */
1625 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1627 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1630 /* REG is the enclosing region for a possible cleanup region, or the region
1631 itself. Returns TRUE if such a region would be unreachable.
1633 Cleanup regions within a must-not-throw region aren't actually reachable
1634 even if there are throwing stmts within them, because the personality
1635 routine will call terminate before unwinding. */
1638 cleanup_is_dead_in (eh_region reg
)
1640 while (reg
&& reg
->type
== ERT_CLEANUP
)
1642 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1645 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1646 to a sequence of labels and blocks, plus the exception region trees
1647 that record all the magic. This is complicated by the need to
1648 arrange for the FINALLY block to be executed on all exits. */
1651 lower_try_finally (struct leh_state
*state
, gimple tp
)
1653 struct leh_tf_state this_tf
;
1654 struct leh_state this_state
;
1656 gimple_seq old_eh_seq
;
1658 /* Process the try block. */
1660 memset (&this_tf
, 0, sizeof (this_tf
));
1661 this_tf
.try_finally_expr
= tp
;
1663 this_tf
.outer
= state
;
1664 if (using_eh_for_cleanups_p () && !cleanup_is_dead_in (state
->cur_region
))
1666 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1667 this_state
.cur_region
= this_tf
.region
;
1671 this_tf
.region
= NULL
;
1672 this_state
.cur_region
= state
->cur_region
;
1675 this_state
.ehp_region
= state
->ehp_region
;
1676 this_state
.tf
= &this_tf
;
1678 old_eh_seq
= eh_seq
;
1681 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1683 /* Determine if the try block is escaped through the bottom. */
1684 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1686 /* Determine if any exceptions are possible within the try block. */
1688 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1689 if (this_tf
.may_throw
)
1690 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1692 /* Determine how many edges (still) reach the finally block. Or rather,
1693 how many destinations are reached by the finally block. Use this to
1694 determine how we process the finally block itself. */
1696 ndests
= this_tf
.dest_array
.length ();
1697 ndests
+= this_tf
.may_fallthru
;
1698 ndests
+= this_tf
.may_return
;
1699 ndests
+= this_tf
.may_throw
;
1701 /* If the FINALLY block is not reachable, dike it out. */
1704 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1705 gimple_try_set_cleanup (tp
, NULL
);
1707 /* If the finally block doesn't fall through, then any destination
1708 we might try to impose there isn't reached either. There may be
1709 some minor amount of cleanup and redirection still needed. */
1710 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1711 lower_try_finally_nofallthru (state
, &this_tf
);
1713 /* We can easily special-case redirection to a single destination. */
1714 else if (ndests
== 1)
1715 lower_try_finally_onedest (state
, &this_tf
);
1716 else if (decide_copy_try_finally (ndests
, this_tf
.may_throw
,
1717 gimple_try_cleanup (tp
)))
1718 lower_try_finally_copy (state
, &this_tf
);
1720 lower_try_finally_switch (state
, &this_tf
);
1722 /* If someone requested we add a label at the end of the transformed
1724 if (this_tf
.fallthru_label
)
1726 /* This must be reached only if ndests == 0. */
1727 gimple x
= gimple_build_label (this_tf
.fallthru_label
);
1728 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1731 this_tf
.dest_array
.release ();
1732 free (this_tf
.goto_queue
);
1733 if (this_tf
.goto_queue_map
)
1734 pointer_map_destroy (this_tf
.goto_queue_map
);
1736 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1737 If there was no old eh_seq, then the append is trivially already done. */
1741 eh_seq
= old_eh_seq
;
1744 gimple_seq new_eh_seq
= eh_seq
;
1745 eh_seq
= old_eh_seq
;
1746 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1750 return this_tf
.top_p_seq
;
1753 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1754 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1755 exception region trees that records all the magic. */
1758 lower_catch (struct leh_state
*state
, gimple tp
)
1760 eh_region try_region
= NULL
;
1761 struct leh_state this_state
= *state
;
1762 gimple_stmt_iterator gsi
;
1764 gimple_seq new_seq
, cleanup
;
1766 location_t try_catch_loc
= gimple_location (tp
);
1768 if (flag_exceptions
)
1770 try_region
= gen_eh_region_try (state
->cur_region
);
1771 this_state
.cur_region
= try_region
;
1774 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1776 if (!eh_region_may_contain_throw (try_region
))
1777 return gimple_try_eval (tp
);
1780 emit_eh_dispatch (&new_seq
, try_region
);
1781 emit_resx (&new_seq
, try_region
);
1783 this_state
.cur_region
= state
->cur_region
;
1784 this_state
.ehp_region
= try_region
;
1787 cleanup
= gimple_try_cleanup (tp
);
1788 for (gsi
= gsi_start (cleanup
);
1796 gcatch
= gsi_stmt (gsi
);
1797 c
= gen_eh_region_catch (try_region
, gimple_catch_types (gcatch
));
1799 handler
= gimple_catch_handler (gcatch
);
1800 lower_eh_constructs_1 (&this_state
, &handler
);
1802 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1803 x
= gimple_build_label (c
->label
);
1804 gimple_seq_add_stmt (&new_seq
, x
);
1806 gimple_seq_add_seq (&new_seq
, handler
);
1808 if (gimple_seq_may_fallthru (new_seq
))
1811 out_label
= create_artificial_label (try_catch_loc
);
1813 x
= gimple_build_goto (out_label
);
1814 gimple_seq_add_stmt (&new_seq
, x
);
1820 gimple_try_set_cleanup (tp
, new_seq
);
1822 return frob_into_branch_around (tp
, try_region
, out_label
);
1825 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1826 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1827 region trees that record all the magic. */
1830 lower_eh_filter (struct leh_state
*state
, gimple tp
)
1832 struct leh_state this_state
= *state
;
1833 eh_region this_region
= NULL
;
1837 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1839 if (flag_exceptions
)
1841 this_region
= gen_eh_region_allowed (state
->cur_region
,
1842 gimple_eh_filter_types (inner
));
1843 this_state
.cur_region
= this_region
;
1846 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1848 if (!eh_region_may_contain_throw (this_region
))
1849 return gimple_try_eval (tp
);
1852 this_state
.cur_region
= state
->cur_region
;
1853 this_state
.ehp_region
= this_region
;
1855 emit_eh_dispatch (&new_seq
, this_region
);
1856 emit_resx (&new_seq
, this_region
);
1858 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1859 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1860 gimple_seq_add_stmt (&new_seq
, x
);
1862 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure_ptr (inner
));
1863 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1865 gimple_try_set_cleanup (tp
, new_seq
);
1867 return frob_into_branch_around (tp
, this_region
, NULL
);
1870 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1871 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1872 plus the exception region trees that record all the magic. */
1875 lower_eh_must_not_throw (struct leh_state
*state
, gimple tp
)
1877 struct leh_state this_state
= *state
;
1879 if (flag_exceptions
)
1881 gimple inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1882 eh_region this_region
;
1884 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1885 this_region
->u
.must_not_throw
.failure_decl
1886 = gimple_eh_must_not_throw_fndecl (inner
);
1887 this_region
->u
.must_not_throw
.failure_loc
1888 = LOCATION_LOCUS (gimple_location (tp
));
1890 /* In order to get mangling applied to this decl, we must mark it
1891 used now. Otherwise, pass_ipa_free_lang_data won't think it
1893 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1895 this_state
.cur_region
= this_region
;
1898 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1900 return gimple_try_eval (tp
);
1903 /* Implement a cleanup expression. This is similar to try-finally,
1904 except that we only execute the cleanup block for exception edges. */
1907 lower_cleanup (struct leh_state
*state
, gimple tp
)
1909 struct leh_state this_state
= *state
;
1910 eh_region this_region
= NULL
;
1911 struct leh_tf_state fake_tf
;
1913 bool cleanup_dead
= cleanup_is_dead_in (state
->cur_region
);
1915 if (flag_exceptions
&& !cleanup_dead
)
1917 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1918 this_state
.cur_region
= this_region
;
1921 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1923 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1924 return gimple_try_eval (tp
);
1926 /* Build enough of a try-finally state so that we can reuse
1927 honor_protect_cleanup_actions. */
1928 memset (&fake_tf
, 0, sizeof (fake_tf
));
1929 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1930 fake_tf
.outer
= state
;
1931 fake_tf
.region
= this_region
;
1932 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1933 fake_tf
.may_throw
= true;
1935 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1937 if (fake_tf
.may_throw
)
1939 /* In this case honor_protect_cleanup_actions had nothing to do,
1940 and we should process this normally. */
1941 lower_eh_constructs_1 (state
, gimple_try_cleanup_ptr (tp
));
1942 result
= frob_into_branch_around (tp
, this_region
,
1943 fake_tf
.fallthru_label
);
1947 /* In this case honor_protect_cleanup_actions did nearly all of
1948 the work. All we have left is to append the fallthru_label. */
1950 result
= gimple_try_eval (tp
);
1951 if (fake_tf
.fallthru_label
)
1953 gimple x
= gimple_build_label (fake_tf
.fallthru_label
);
1954 gimple_seq_add_stmt (&result
, x
);
1960 /* Main loop for lowering eh constructs. Also moves gsi to the next
1964 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1968 gimple stmt
= gsi_stmt (*gsi
);
1970 switch (gimple_code (stmt
))
1974 tree fndecl
= gimple_call_fndecl (stmt
);
1977 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1978 switch (DECL_FUNCTION_CODE (fndecl
))
1980 case BUILT_IN_EH_POINTER
:
1981 /* The front end may have generated a call to
1982 __builtin_eh_pointer (0) within a catch region. Replace
1983 this zero argument with the current catch region number. */
1984 if (state
->ehp_region
)
1986 tree nr
= build_int_cst (integer_type_node
,
1987 state
->ehp_region
->index
);
1988 gimple_call_set_arg (stmt
, 0, nr
);
1992 /* The user has dome something silly. Remove it. */
1993 rhs
= null_pointer_node
;
1998 case BUILT_IN_EH_FILTER
:
1999 /* ??? This should never appear, but since it's a builtin it
2000 is accessible to abuse by users. Just remove it and
2001 replace the use with the arbitrary value zero. */
2002 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
2004 lhs
= gimple_call_lhs (stmt
);
2005 x
= gimple_build_assign (lhs
, rhs
);
2006 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
2009 case BUILT_IN_EH_COPY_VALUES
:
2010 /* Likewise this should not appear. Remove it. */
2011 gsi_remove (gsi
, true);
2021 /* If the stmt can throw use a new temporary for the assignment
2022 to a LHS. This makes sure the old value of the LHS is
2023 available on the EH edge. Only do so for statements that
2024 potentially fall through (no noreturn calls e.g.), otherwise
2025 this new assignment might create fake fallthru regions. */
2026 if (stmt_could_throw_p (stmt
)
2027 && gimple_has_lhs (stmt
)
2028 && gimple_stmt_may_fallthru (stmt
)
2029 && !tree_could_throw_p (gimple_get_lhs (stmt
))
2030 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
2032 tree lhs
= gimple_get_lhs (stmt
);
2033 tree tmp
= create_tmp_var (TREE_TYPE (lhs
), NULL
);
2034 gimple s
= gimple_build_assign (lhs
, tmp
);
2035 gimple_set_location (s
, gimple_location (stmt
));
2036 gimple_set_block (s
, gimple_block (stmt
));
2037 gimple_set_lhs (stmt
, tmp
);
2038 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
2039 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
2040 DECL_GIMPLE_REG_P (tmp
) = 1;
2041 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
2043 /* Look for things that can throw exceptions, and record them. */
2044 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
2046 record_stmt_eh_region (state
->cur_region
, stmt
);
2047 note_eh_region_may_contain_throw (state
->cur_region
);
2054 maybe_record_in_goto_queue (state
, stmt
);
2058 verify_norecord_switch_expr (state
, stmt
);
2062 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
2063 replace
= lower_try_finally (state
, stmt
);
2066 x
= gimple_seq_first_stmt (gimple_try_cleanup (stmt
));
2069 replace
= gimple_try_eval (stmt
);
2070 lower_eh_constructs_1 (state
, &replace
);
2073 switch (gimple_code (x
))
2076 replace
= lower_catch (state
, stmt
);
2078 case GIMPLE_EH_FILTER
:
2079 replace
= lower_eh_filter (state
, stmt
);
2081 case GIMPLE_EH_MUST_NOT_THROW
:
2082 replace
= lower_eh_must_not_throw (state
, stmt
);
2084 case GIMPLE_EH_ELSE
:
2085 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2088 replace
= lower_cleanup (state
, stmt
);
2093 /* Remove the old stmt and insert the transformed sequence
2095 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2096 gsi_remove (gsi
, true);
2098 /* Return since we don't want gsi_next () */
2101 case GIMPLE_EH_ELSE
:
2102 /* We should be eliminating this in lower_try_finally et al. */
2106 /* A type, a decl, or some kind of statement that we're not
2107 interested in. Don't walk them. */
2114 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2117 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*pseq
)
2119 gimple_stmt_iterator gsi
;
2120 for (gsi
= gsi_start (*pseq
); !gsi_end_p (gsi
);)
2121 lower_eh_constructs_2 (state
, &gsi
);
2125 lower_eh_constructs (void)
2127 struct leh_state null_state
;
2130 bodyp
= gimple_body (current_function_decl
);
2134 finally_tree
.create (31);
2135 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2136 memset (&null_state
, 0, sizeof (null_state
));
2138 collect_finally_tree_1 (bodyp
, NULL
);
2139 lower_eh_constructs_1 (&null_state
, &bodyp
);
2140 gimple_set_body (current_function_decl
, bodyp
);
2142 /* We assume there's a return statement, or something, at the end of
2143 the function, and thus ploping the EH sequence afterward won't
2145 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2146 gimple_seq_add_seq (&bodyp
, eh_seq
);
2148 /* We assume that since BODYP already existed, adding EH_SEQ to it
2149 didn't change its value, and we don't have to re-set the function. */
2150 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2152 finally_tree
.dispose ();
2153 BITMAP_FREE (eh_region_may_contain_throw_map
);
2156 /* If this function needs a language specific EH personality routine
2157 and the frontend didn't already set one do so now. */
2158 if (function_needs_eh_personality (cfun
) == eh_personality_lang
2159 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2160 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2161 = lang_hooks
.eh_personality ();
2168 const pass_data pass_data_lower_eh
=
2170 GIMPLE_PASS
, /* type */
2172 OPTGROUP_NONE
, /* optinfo_flags */
2173 false, /* has_gate */
2174 true, /* has_execute */
2175 TV_TREE_EH
, /* tv_id */
2176 PROP_gimple_lcf
, /* properties_required */
2177 PROP_gimple_leh
, /* properties_provided */
2178 0, /* properties_destroyed */
2179 0, /* todo_flags_start */
2180 0, /* todo_flags_finish */
2183 class pass_lower_eh
: public gimple_opt_pass
2186 pass_lower_eh (gcc::context
*ctxt
)
2187 : gimple_opt_pass (pass_data_lower_eh
, ctxt
)
2190 /* opt_pass methods: */
2191 unsigned int execute () { return lower_eh_constructs (); }
2193 }; // class pass_lower_eh
2198 make_pass_lower_eh (gcc::context
*ctxt
)
2200 return new pass_lower_eh (ctxt
);
2203 /* Create the multiple edges from an EH_DISPATCH statement to all of
2204 the possible handlers for its EH region. Return true if there's
2205 no fallthru edge; false if there is. */
2208 make_eh_dispatch_edges (gimple stmt
)
2212 basic_block src
, dst
;
2214 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2215 src
= gimple_bb (stmt
);
2220 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2222 dst
= label_to_block (c
->label
);
2223 make_edge (src
, dst
, 0);
2225 /* A catch-all handler doesn't have a fallthru. */
2226 if (c
->type_list
== NULL
)
2231 case ERT_ALLOWED_EXCEPTIONS
:
2232 dst
= label_to_block (r
->u
.allowed
.label
);
2233 make_edge (src
, dst
, 0);
2243 /* Create the single EH edge from STMT to its nearest landing pad,
2244 if there is such a landing pad within the current function. */
2247 make_eh_edges (gimple stmt
)
2249 basic_block src
, dst
;
2253 lp_nr
= lookup_stmt_eh_lp (stmt
);
2257 lp
= get_eh_landing_pad_from_number (lp_nr
);
2258 gcc_assert (lp
!= NULL
);
2260 src
= gimple_bb (stmt
);
2261 dst
= label_to_block (lp
->post_landing_pad
);
2262 make_edge (src
, dst
, EDGE_EH
);
2265 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2266 do not actually perform the final edge redirection.
2268 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2269 we intend to change the destination EH region as well; this means
2270 EH_LANDING_PAD_NR must already be set on the destination block label.
2271 If false, we're being called from generic cfg manipulation code and we
2272 should preserve our place within the region tree. */
2275 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2277 eh_landing_pad old_lp
, new_lp
;
2280 int old_lp_nr
, new_lp_nr
;
2281 tree old_label
, new_label
;
2285 old_bb
= edge_in
->dest
;
2286 old_label
= gimple_block_label (old_bb
);
2287 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2288 gcc_assert (old_lp_nr
> 0);
2289 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2291 throw_stmt
= last_stmt (edge_in
->src
);
2292 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2294 new_label
= gimple_block_label (new_bb
);
2296 /* Look for an existing region that might be using NEW_BB already. */
2297 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2300 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2301 gcc_assert (new_lp
);
2303 /* Unless CHANGE_REGION is true, the new and old landing pad
2304 had better be associated with the same EH region. */
2305 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2310 gcc_assert (!change_region
);
2313 /* Notice when we redirect the last EH edge away from OLD_BB. */
2314 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2315 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2320 /* NEW_LP already exists. If there are still edges into OLD_LP,
2321 there's nothing to do with the EH tree. If there are no more
2322 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2323 If CHANGE_REGION is true, then our caller is expecting to remove
2325 if (e
== NULL
&& !change_region
)
2326 remove_eh_landing_pad (old_lp
);
2330 /* No correct landing pad exists. If there are no more edges
2331 into OLD_LP, then we can simply re-use the existing landing pad.
2332 Otherwise, we have to create a new landing pad. */
2335 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2339 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2340 new_lp
->post_landing_pad
= new_label
;
2341 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2344 /* Maybe move the throwing statement to the new region. */
2345 if (old_lp
!= new_lp
)
2347 remove_stmt_from_eh_lp (throw_stmt
);
2348 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2352 /* Redirect EH edge E to NEW_BB. */
2355 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2357 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2358 return ssa_redirect_edge (edge_in
, new_bb
);
2361 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2362 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2363 The actual edge update will happen in the caller. */
2366 redirect_eh_dispatch_edge (gimple stmt
, edge e
, basic_block new_bb
)
2368 tree new_lab
= gimple_block_label (new_bb
);
2369 bool any_changed
= false;
2374 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2378 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2380 old_bb
= label_to_block (c
->label
);
2381 if (old_bb
== e
->dest
)
2389 case ERT_ALLOWED_EXCEPTIONS
:
2390 old_bb
= label_to_block (r
->u
.allowed
.label
);
2391 gcc_assert (old_bb
== e
->dest
);
2392 r
->u
.allowed
.label
= new_lab
;
2400 gcc_assert (any_changed
);
2403 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2406 operation_could_trap_helper_p (enum tree_code op
,
2417 case TRUNC_DIV_EXPR
:
2419 case FLOOR_DIV_EXPR
:
2420 case ROUND_DIV_EXPR
:
2421 case EXACT_DIV_EXPR
:
2423 case FLOOR_MOD_EXPR
:
2424 case ROUND_MOD_EXPR
:
2425 case TRUNC_MOD_EXPR
:
2427 if (honor_snans
|| honor_trapv
)
2430 return flag_trapping_math
;
2431 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2440 /* Some floating point comparisons may trap. */
2445 case UNORDERED_EXPR
:
2455 case FIX_TRUNC_EXPR
:
2456 /* Conversion of floating point might trap. */
2462 /* These operations don't trap with floating point. */
2470 /* Any floating arithmetic may trap. */
2471 if (fp_operation
&& flag_trapping_math
)
2479 /* Constructing an object cannot trap. */
2483 /* Any floating arithmetic may trap. */
2484 if (fp_operation
&& flag_trapping_math
)
2492 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2493 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2494 type operands that may trap. If OP is a division operator, DIVISOR contains
2495 the value of the divisor. */
2498 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2501 bool honor_nans
= (fp_operation
&& flag_trapping_math
2502 && !flag_finite_math_only
);
2503 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2506 if (TREE_CODE_CLASS (op
) != tcc_comparison
2507 && TREE_CODE_CLASS (op
) != tcc_unary
2508 && TREE_CODE_CLASS (op
) != tcc_binary
)
2511 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2512 honor_nans
, honor_snans
, divisor
,
2517 /* Returns true if it is possible to prove that the index of
2518 an array access REF (an ARRAY_REF expression) falls into the
2522 in_array_bounds_p (tree ref
)
2524 tree idx
= TREE_OPERAND (ref
, 1);
2527 if (TREE_CODE (idx
) != INTEGER_CST
)
2530 min
= array_ref_low_bound (ref
);
2531 max
= array_ref_up_bound (ref
);
2534 || TREE_CODE (min
) != INTEGER_CST
2535 || TREE_CODE (max
) != INTEGER_CST
)
2538 if (tree_int_cst_lt (idx
, min
)
2539 || tree_int_cst_lt (max
, idx
))
2545 /* Returns true if it is possible to prove that the range of
2546 an array access REF (an ARRAY_RANGE_REF expression) falls
2547 into the array bounds. */
2550 range_in_array_bounds_p (tree ref
)
2552 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (ref
));
2553 tree range_min
, range_max
, min
, max
;
2555 range_min
= TYPE_MIN_VALUE (domain_type
);
2556 range_max
= TYPE_MAX_VALUE (domain_type
);
2559 || TREE_CODE (range_min
) != INTEGER_CST
2560 || TREE_CODE (range_max
) != INTEGER_CST
)
2563 min
= array_ref_low_bound (ref
);
2564 max
= array_ref_up_bound (ref
);
2567 || TREE_CODE (min
) != INTEGER_CST
2568 || TREE_CODE (max
) != INTEGER_CST
)
2571 if (tree_int_cst_lt (range_min
, min
)
2572 || tree_int_cst_lt (max
, range_max
))
2578 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2579 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2580 This routine expects only GIMPLE lhs or rhs input. */
2583 tree_could_trap_p (tree expr
)
2585 enum tree_code code
;
2586 bool fp_operation
= false;
2587 bool honor_trapv
= false;
2588 tree t
, base
, div
= NULL_TREE
;
2593 code
= TREE_CODE (expr
);
2594 t
= TREE_TYPE (expr
);
2598 if (COMPARISON_CLASS_P (expr
))
2599 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2601 fp_operation
= FLOAT_TYPE_P (t
);
2602 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2605 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2606 div
= TREE_OPERAND (expr
, 1);
2607 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2613 case TARGET_MEM_REF
:
2614 if (TREE_CODE (TMR_BASE (expr
)) == ADDR_EXPR
2615 && !TMR_INDEX (expr
) && !TMR_INDEX2 (expr
))
2617 return !TREE_THIS_NOTRAP (expr
);
2623 case VIEW_CONVERT_EXPR
:
2624 case WITH_SIZE_EXPR
:
2625 expr
= TREE_OPERAND (expr
, 0);
2626 code
= TREE_CODE (expr
);
2629 case ARRAY_RANGE_REF
:
2630 base
= TREE_OPERAND (expr
, 0);
2631 if (tree_could_trap_p (base
))
2633 if (TREE_THIS_NOTRAP (expr
))
2635 return !range_in_array_bounds_p (expr
);
2638 base
= TREE_OPERAND (expr
, 0);
2639 if (tree_could_trap_p (base
))
2641 if (TREE_THIS_NOTRAP (expr
))
2643 return !in_array_bounds_p (expr
);
2646 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2650 return !TREE_THIS_NOTRAP (expr
);
2653 return TREE_THIS_VOLATILE (expr
);
2656 t
= get_callee_fndecl (expr
);
2657 /* Assume that calls to weak functions may trap. */
2658 if (!t
|| !DECL_P (t
))
2661 return tree_could_trap_p (t
);
2665 /* Assume that accesses to weak functions may trap, unless we know
2666 they are certainly defined in current TU or in some other
2668 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
))
2670 struct cgraph_node
*node
;
2671 if (!DECL_EXTERNAL (expr
))
2673 node
= cgraph_function_node (cgraph_get_node (expr
), NULL
);
2674 if (node
&& node
->in_other_partition
)
2681 /* Assume that accesses to weak vars may trap, unless we know
2682 they are certainly defined in current TU or in some other
2684 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
))
2687 if (!DECL_EXTERNAL (expr
))
2689 node
= varpool_variable_node (varpool_get_node (expr
), NULL
);
2690 if (node
&& node
->in_other_partition
)
2702 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2703 an assignment or a conditional) may throw. */
2706 stmt_could_throw_1_p (gimple stmt
)
2708 enum tree_code code
= gimple_expr_code (stmt
);
2709 bool honor_nans
= false;
2710 bool honor_snans
= false;
2711 bool fp_operation
= false;
2712 bool honor_trapv
= false;
2717 if (TREE_CODE_CLASS (code
) == tcc_comparison
2718 || TREE_CODE_CLASS (code
) == tcc_unary
2719 || TREE_CODE_CLASS (code
) == tcc_binary
)
2721 if (is_gimple_assign (stmt
)
2722 && TREE_CODE_CLASS (code
) == tcc_comparison
)
2723 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2724 else if (gimple_code (stmt
) == GIMPLE_COND
)
2725 t
= TREE_TYPE (gimple_cond_lhs (stmt
));
2727 t
= gimple_expr_type (stmt
);
2728 fp_operation
= FLOAT_TYPE_P (t
);
2731 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2732 honor_snans
= flag_signaling_nans
!= 0;
2734 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2738 /* Check if the main expression may trap. */
2739 t
= is_gimple_assign (stmt
) ? gimple_assign_rhs2 (stmt
) : NULL
;
2740 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2741 honor_nans
, honor_snans
, t
,
2746 /* If the expression does not trap, see if any of the individual operands may
2748 for (i
= 0; i
< gimple_num_ops (stmt
); i
++)
2749 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2756 /* Return true if statement STMT could throw an exception. */
2759 stmt_could_throw_p (gimple stmt
)
2761 if (!flag_exceptions
)
2764 /* The only statements that can throw an exception are assignments,
2765 conditionals, calls, resx, and asms. */
2766 switch (gimple_code (stmt
))
2772 return !gimple_call_nothrow_p (stmt
);
2776 if (!cfun
->can_throw_non_call_exceptions
)
2778 return stmt_could_throw_1_p (stmt
);
2781 if (!cfun
->can_throw_non_call_exceptions
)
2783 return gimple_asm_volatile_p (stmt
);
2791 /* Return true if expression T could throw an exception. */
2794 tree_could_throw_p (tree t
)
2796 if (!flag_exceptions
)
2798 if (TREE_CODE (t
) == MODIFY_EXPR
)
2800 if (cfun
->can_throw_non_call_exceptions
2801 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2803 t
= TREE_OPERAND (t
, 1);
2806 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2807 t
= TREE_OPERAND (t
, 0);
2808 if (TREE_CODE (t
) == CALL_EXPR
)
2809 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2810 if (cfun
->can_throw_non_call_exceptions
)
2811 return tree_could_trap_p (t
);
2815 /* Return true if STMT can throw an exception that is not caught within
2816 the current function (CFUN). */
2819 stmt_can_throw_external (gimple stmt
)
2823 if (!stmt_could_throw_p (stmt
))
2826 lp_nr
= lookup_stmt_eh_lp (stmt
);
2830 /* Return true if STMT can throw an exception that is caught within
2831 the current function (CFUN). */
2834 stmt_can_throw_internal (gimple stmt
)
2838 if (!stmt_could_throw_p (stmt
))
2841 lp_nr
= lookup_stmt_eh_lp (stmt
);
2845 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2846 remove any entry it might have from the EH table. Return true if
2847 any change was made. */
2850 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple stmt
)
2852 if (stmt_could_throw_p (stmt
))
2854 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2857 /* Likewise, but always use the current function. */
2860 maybe_clean_eh_stmt (gimple stmt
)
2862 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2865 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2866 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2867 in the table if it should be in there. Return TRUE if a replacement was
2868 done that my require an EH edge purge. */
2871 maybe_clean_or_replace_eh_stmt (gimple old_stmt
, gimple new_stmt
)
2873 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2877 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2879 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2882 remove_stmt_from_eh_lp (old_stmt
);
2883 if (new_stmt_could_throw
)
2885 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2895 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
2896 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2897 operand is the return value of duplicate_eh_regions. */
2900 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple new_stmt
,
2901 struct function
*old_fun
, gimple old_stmt
,
2902 struct pointer_map_t
*map
, int default_lp_nr
)
2904 int old_lp_nr
, new_lp_nr
;
2907 if (!stmt_could_throw_p (new_stmt
))
2910 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2913 if (default_lp_nr
== 0)
2915 new_lp_nr
= default_lp_nr
;
2917 else if (old_lp_nr
> 0)
2919 eh_landing_pad old_lp
, new_lp
;
2921 old_lp
= (*old_fun
->eh
->lp_array
)[old_lp_nr
];
2922 slot
= pointer_map_contains (map
, old_lp
);
2923 new_lp
= (eh_landing_pad
) *slot
;
2924 new_lp_nr
= new_lp
->index
;
2928 eh_region old_r
, new_r
;
2930 old_r
= (*old_fun
->eh
->region_array
)[-old_lp_nr
];
2931 slot
= pointer_map_contains (map
, old_r
);
2932 new_r
= (eh_region
) *slot
;
2933 new_lp_nr
= -new_r
->index
;
2936 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2940 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2941 and thus no remapping is required. */
2944 maybe_duplicate_eh_stmt (gimple new_stmt
, gimple old_stmt
)
2948 if (!stmt_could_throw_p (new_stmt
))
2951 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2955 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2959 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2960 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2961 this only handles handlers consisting of a single call, as that's the
2962 important case for C++: a destructor call for a particular object showing
2963 up in multiple handlers. */
2966 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2968 gimple_stmt_iterator gsi
;
2972 gsi
= gsi_start (oneh
);
2973 if (!gsi_one_before_end_p (gsi
))
2975 ones
= gsi_stmt (gsi
);
2977 gsi
= gsi_start (twoh
);
2978 if (!gsi_one_before_end_p (gsi
))
2980 twos
= gsi_stmt (gsi
);
2982 if (!is_gimple_call (ones
)
2983 || !is_gimple_call (twos
)
2984 || gimple_call_lhs (ones
)
2985 || gimple_call_lhs (twos
)
2986 || gimple_call_chain (ones
)
2987 || gimple_call_chain (twos
)
2988 || !gimple_call_same_target_p (ones
, twos
)
2989 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
2992 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
2993 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
2994 gimple_call_arg (twos
, ai
), 0))
3001 try { A() } finally { try { ~B() } catch { ~A() } }
3002 try { ... } finally { ~A() }
3004 try { A() } catch { ~B() }
3005 try { ~B() ... } finally { ~A() }
3007 This occurs frequently in C++, where A is a local variable and B is a
3008 temporary used in the initializer for A. */
3011 optimize_double_finally (gimple one
, gimple two
)
3014 gimple_stmt_iterator gsi
;
3017 cleanup
= gimple_try_cleanup (one
);
3018 gsi
= gsi_start (cleanup
);
3019 if (!gsi_one_before_end_p (gsi
))
3022 oneh
= gsi_stmt (gsi
);
3023 if (gimple_code (oneh
) != GIMPLE_TRY
3024 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
3027 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
3029 gimple_seq seq
= gimple_try_eval (oneh
);
3031 gimple_try_set_cleanup (one
, seq
);
3032 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
3033 seq
= copy_gimple_seq_and_replace_locals (seq
);
3034 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
3035 gimple_try_set_eval (two
, seq
);
3039 /* Perform EH refactoring optimizations that are simpler to do when code
3040 flow has been lowered but EH structures haven't. */
3043 refactor_eh_r (gimple_seq seq
)
3045 gimple_stmt_iterator gsi
;
3050 gsi
= gsi_start (seq
);
3054 if (gsi_end_p (gsi
))
3057 two
= gsi_stmt (gsi
);
3060 && gimple_code (one
) == GIMPLE_TRY
3061 && gimple_code (two
) == GIMPLE_TRY
3062 && gimple_try_kind (one
) == GIMPLE_TRY_FINALLY
3063 && gimple_try_kind (two
) == GIMPLE_TRY_FINALLY
)
3064 optimize_double_finally (one
, two
);
3066 switch (gimple_code (one
))
3069 refactor_eh_r (gimple_try_eval (one
));
3070 refactor_eh_r (gimple_try_cleanup (one
));
3073 refactor_eh_r (gimple_catch_handler (one
));
3075 case GIMPLE_EH_FILTER
:
3076 refactor_eh_r (gimple_eh_filter_failure (one
));
3078 case GIMPLE_EH_ELSE
:
3079 refactor_eh_r (gimple_eh_else_n_body (one
));
3080 refactor_eh_r (gimple_eh_else_e_body (one
));
3095 refactor_eh_r (gimple_body (current_function_decl
));
3100 gate_refactor_eh (void)
3102 return flag_exceptions
!= 0;
3107 const pass_data pass_data_refactor_eh
=
3109 GIMPLE_PASS
, /* type */
3111 OPTGROUP_NONE
, /* optinfo_flags */
3112 true, /* has_gate */
3113 true, /* has_execute */
3114 TV_TREE_EH
, /* tv_id */
3115 PROP_gimple_lcf
, /* properties_required */
3116 0, /* properties_provided */
3117 0, /* properties_destroyed */
3118 0, /* todo_flags_start */
3119 0, /* todo_flags_finish */
3122 class pass_refactor_eh
: public gimple_opt_pass
3125 pass_refactor_eh (gcc::context
*ctxt
)
3126 : gimple_opt_pass (pass_data_refactor_eh
, ctxt
)
3129 /* opt_pass methods: */
3130 bool gate () { return gate_refactor_eh (); }
3131 unsigned int execute () { return refactor_eh (); }
3133 }; // class pass_refactor_eh
3138 make_pass_refactor_eh (gcc::context
*ctxt
)
3140 return new pass_refactor_eh (ctxt
);
3143 /* At the end of gimple optimization, we can lower RESX. */
3146 lower_resx (basic_block bb
, gimple stmt
, struct pointer_map_t
*mnt_map
)
3149 eh_region src_r
, dst_r
;
3150 gimple_stmt_iterator gsi
;
3155 lp_nr
= lookup_stmt_eh_lp (stmt
);
3157 dst_r
= get_eh_region_from_lp_number (lp_nr
);
3161 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
3162 gsi
= gsi_last_bb (bb
);
3166 /* We can wind up with no source region when pass_cleanup_eh shows
3167 that there are no entries into an eh region and deletes it, but
3168 then the block that contains the resx isn't removed. This can
3169 happen without optimization when the switch statement created by
3170 lower_try_finally_switch isn't simplified to remove the eh case.
3172 Resolve this by expanding the resx node to an abort. */
3174 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3175 x
= gimple_build_call (fn
, 0);
3176 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3178 while (EDGE_COUNT (bb
->succs
) > 0)
3179 remove_edge (EDGE_SUCC (bb
, 0));
3183 /* When we have a destination region, we resolve this by copying
3184 the excptr and filter values into place, and changing the edge
3185 to immediately after the landing pad. */
3194 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3195 the failure decl into a new block, if needed. */
3196 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3198 slot
= pointer_map_contains (mnt_map
, dst_r
);
3201 gimple_stmt_iterator gsi2
;
3203 new_bb
= create_empty_bb (bb
);
3205 add_bb_to_loop (new_bb
, bb
->loop_father
);
3206 lab
= gimple_block_label (new_bb
);
3207 gsi2
= gsi_start_bb (new_bb
);
3209 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3210 x
= gimple_build_call (fn
, 0);
3211 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3212 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3214 slot
= pointer_map_insert (mnt_map
, dst_r
);
3220 new_bb
= label_to_block (lab
);
3223 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3224 e
= make_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3225 e
->count
= bb
->count
;
3226 e
->probability
= REG_BR_PROB_BASE
;
3231 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3233 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3234 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3235 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3236 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3238 /* Update the flags for the outgoing edge. */
3239 e
= single_succ_edge (bb
);
3240 gcc_assert (e
->flags
& EDGE_EH
);
3241 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3243 /* If there are no more EH users of the landing pad, delete it. */
3244 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3245 if (e
->flags
& EDGE_EH
)
3249 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3250 remove_eh_landing_pad (lp
);
3260 /* When we don't have a destination region, this exception escapes
3261 up the call chain. We resolve this by generating a call to the
3262 _Unwind_Resume library function. */
3264 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3265 with no arguments for C++ and Java. Check for that. */
3266 if (src_r
->use_cxa_end_cleanup
)
3268 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3269 x
= gimple_build_call (fn
, 0);
3270 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3274 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3275 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3276 x
= gimple_build_call (fn
, 1, src_nr
);
3277 var
= create_tmp_var (ptr_type_node
, NULL
);
3278 var
= make_ssa_name (var
, x
);
3279 gimple_call_set_lhs (x
, var
);
3280 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3282 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3283 x
= gimple_build_call (fn
, 1, var
);
3284 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3287 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3290 gsi_remove (&gsi
, true);
3296 execute_lower_resx (void)
3299 struct pointer_map_t
*mnt_map
;
3300 bool dominance_invalidated
= false;
3301 bool any_rewritten
= false;
3303 mnt_map
= pointer_map_create ();
3305 FOR_EACH_BB_FN (bb
, cfun
)
3307 gimple last
= last_stmt (bb
);
3308 if (last
&& is_gimple_resx (last
))
3310 dominance_invalidated
|= lower_resx (bb
, last
, mnt_map
);
3311 any_rewritten
= true;
3315 pointer_map_destroy (mnt_map
);
3317 if (dominance_invalidated
)
3319 free_dominance_info (CDI_DOMINATORS
);
3320 free_dominance_info (CDI_POST_DOMINATORS
);
3323 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3327 gate_lower_resx (void)
3329 return flag_exceptions
!= 0;
3334 const pass_data pass_data_lower_resx
=
3336 GIMPLE_PASS
, /* type */
3338 OPTGROUP_NONE
, /* optinfo_flags */
3339 true, /* has_gate */
3340 true, /* has_execute */
3341 TV_TREE_EH
, /* tv_id */
3342 PROP_gimple_lcf
, /* properties_required */
3343 0, /* properties_provided */
3344 0, /* properties_destroyed */
3345 0, /* todo_flags_start */
3346 TODO_verify_flow
, /* todo_flags_finish */
3349 class pass_lower_resx
: public gimple_opt_pass
3352 pass_lower_resx (gcc::context
*ctxt
)
3353 : gimple_opt_pass (pass_data_lower_resx
, ctxt
)
3356 /* opt_pass methods: */
3357 bool gate () { return gate_lower_resx (); }
3358 unsigned int execute () { return execute_lower_resx (); }
3360 }; // class pass_lower_resx
3365 make_pass_lower_resx (gcc::context
*ctxt
)
3367 return new pass_lower_resx (ctxt
);
3370 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3374 optimize_clobbers (basic_block bb
)
3376 gimple_stmt_iterator gsi
= gsi_last_bb (bb
);
3377 bool any_clobbers
= false;
3378 bool seen_stack_restore
= false;
3382 /* Only optimize anything if the bb contains at least one clobber,
3383 ends with resx (checked by caller), optionally contains some
3384 debug stmts or labels, or at most one __builtin_stack_restore
3385 call, and has an incoming EH edge. */
3386 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3388 gimple stmt
= gsi_stmt (gsi
);
3389 if (is_gimple_debug (stmt
))
3391 if (gimple_clobber_p (stmt
))
3393 any_clobbers
= true;
3396 if (!seen_stack_restore
3397 && gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
3399 seen_stack_restore
= true;
3402 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3408 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3409 if (e
->flags
& EDGE_EH
)
3413 gsi
= gsi_last_bb (bb
);
3414 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3416 gimple stmt
= gsi_stmt (gsi
);
3417 if (!gimple_clobber_p (stmt
))
3419 unlink_stmt_vdef (stmt
);
3420 gsi_remove (&gsi
, true);
3421 release_defs (stmt
);
3425 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3426 internal throw to successor BB. */
3429 sink_clobbers (basic_block bb
)
3433 gimple_stmt_iterator gsi
, dgsi
;
3435 bool any_clobbers
= false;
3438 /* Only optimize if BB has a single EH successor and
3439 all predecessor edges are EH too. */
3440 if (!single_succ_p (bb
)
3441 || (single_succ_edge (bb
)->flags
& EDGE_EH
) == 0)
3444 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3446 if ((e
->flags
& EDGE_EH
) == 0)
3450 /* And BB contains only CLOBBER stmts before the final
3452 gsi
= gsi_last_bb (bb
);
3453 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3455 gimple stmt
= gsi_stmt (gsi
);
3456 if (is_gimple_debug (stmt
))
3458 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3460 if (!gimple_clobber_p (stmt
))
3462 any_clobbers
= true;
3467 edge succe
= single_succ_edge (bb
);
3468 succbb
= succe
->dest
;
3470 /* See if there is a virtual PHI node to take an updated virtual
3473 tree vuse
= NULL_TREE
;
3474 for (gsi
= gsi_start_phis (succbb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3476 tree res
= gimple_phi_result (gsi_stmt (gsi
));
3477 if (virtual_operand_p (res
))
3479 vphi
= gsi_stmt (gsi
);
3485 dgsi
= gsi_after_labels (succbb
);
3486 gsi
= gsi_last_bb (bb
);
3487 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3489 gimple stmt
= gsi_stmt (gsi
);
3491 if (is_gimple_debug (stmt
))
3493 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3495 lhs
= gimple_assign_lhs (stmt
);
3496 /* Unfortunately we don't have dominance info updated at this
3497 point, so checking if
3498 dominated_by_p (CDI_DOMINATORS, succbb,
3499 gimple_bb (SSA_NAME_DEF_STMT (TREE_OPERAND (lhs, 0)))
3500 would be too costly. Thus, avoid sinking any clobbers that
3501 refer to non-(D) SSA_NAMEs. */
3502 if (TREE_CODE (lhs
) == MEM_REF
3503 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == SSA_NAME
3504 && !SSA_NAME_IS_DEFAULT_DEF (TREE_OPERAND (lhs
, 0)))
3506 unlink_stmt_vdef (stmt
);
3507 gsi_remove (&gsi
, true);
3508 release_defs (stmt
);
3512 /* As we do not change stmt order when sinking across a
3513 forwarder edge we can keep virtual operands in place. */
3514 gsi_remove (&gsi
, false);
3515 gsi_insert_before (&dgsi
, stmt
, GSI_NEW_STMT
);
3517 /* But adjust virtual operands if we sunk across a PHI node. */
3521 imm_use_iterator iter
;
3522 use_operand_p use_p
;
3523 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, vuse
)
3524 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3525 SET_USE (use_p
, gimple_vdef (stmt
));
3526 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
))
3528 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (stmt
)) = 1;
3529 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
) = 0;
3531 /* Adjust the incoming virtual operand. */
3532 SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (vphi
, succe
), gimple_vuse (stmt
));
3533 SET_USE (gimple_vuse_op (stmt
), vuse
);
3535 /* If there isn't a single predecessor but no virtual PHI node
3536 arrange for virtual operands to be renamed. */
3537 else if (gimple_vuse_op (stmt
) != NULL_USE_OPERAND_P
3538 && !single_pred_p (succbb
))
3540 /* In this case there will be no use of the VDEF of this stmt.
3541 ??? Unless this is a secondary opportunity and we have not
3542 removed unreachable blocks yet, so we cannot assert this.
3543 Which also means we will end up renaming too many times. */
3544 SET_USE (gimple_vuse_op (stmt
), gimple_vop (cfun
));
3545 mark_virtual_operands_for_renaming (cfun
);
3546 todo
|= TODO_update_ssa_only_virtuals
;
3553 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3554 we have found some duplicate labels and removed some edges. */
3557 lower_eh_dispatch (basic_block src
, gimple stmt
)
3559 gimple_stmt_iterator gsi
;
3564 bool redirected
= false;
3566 region_nr
= gimple_eh_dispatch_region (stmt
);
3567 r
= get_eh_region_from_number (region_nr
);
3569 gsi
= gsi_last_bb (src
);
3575 auto_vec
<tree
> labels
;
3576 tree default_label
= NULL
;
3580 struct pointer_set_t
*seen_values
= pointer_set_create ();
3582 /* Collect the labels for a switch. Zero the post_landing_pad
3583 field becase we'll no longer have anything keeping these labels
3584 in existence and the optimizer will be free to merge these
3586 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3588 tree tp_node
, flt_node
, lab
= c
->label
;
3589 bool have_label
= false;
3592 tp_node
= c
->type_list
;
3593 flt_node
= c
->filter_list
;
3595 if (tp_node
== NULL
)
3597 default_label
= lab
;
3602 /* Filter out duplicate labels that arise when this handler
3603 is shadowed by an earlier one. When no labels are
3604 attached to the handler anymore, we remove
3605 the corresponding edge and then we delete unreachable
3606 blocks at the end of this pass. */
3607 if (! pointer_set_contains (seen_values
, TREE_VALUE (flt_node
)))
3609 tree t
= build_case_label (TREE_VALUE (flt_node
),
3611 labels
.safe_push (t
);
3612 pointer_set_insert (seen_values
, TREE_VALUE (flt_node
));
3616 tp_node
= TREE_CHAIN (tp_node
);
3617 flt_node
= TREE_CHAIN (flt_node
);
3622 remove_edge (find_edge (src
, label_to_block (lab
)));
3627 /* Clean up the edge flags. */
3628 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3630 if (e
->flags
& EDGE_FALLTHRU
)
3632 /* If there was no catch-all, use the fallthru edge. */
3633 if (default_label
== NULL
)
3634 default_label
= gimple_block_label (e
->dest
);
3635 e
->flags
&= ~EDGE_FALLTHRU
;
3638 gcc_assert (default_label
!= NULL
);
3640 /* Don't generate a switch if there's only a default case.
3641 This is common in the form of try { A; } catch (...) { B; }. */
3642 if (!labels
.exists ())
3644 e
= single_succ_edge (src
);
3645 e
->flags
|= EDGE_FALLTHRU
;
3649 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3650 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3652 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3653 filter
= make_ssa_name (filter
, x
);
3654 gimple_call_set_lhs (x
, filter
);
3655 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3657 /* Turn the default label into a default case. */
3658 default_label
= build_case_label (NULL
, NULL
, default_label
);
3659 sort_case_labels (labels
);
3661 x
= gimple_build_switch (filter
, default_label
, labels
);
3662 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3664 pointer_set_destroy (seen_values
);
3668 case ERT_ALLOWED_EXCEPTIONS
:
3670 edge b_e
= BRANCH_EDGE (src
);
3671 edge f_e
= FALLTHRU_EDGE (src
);
3673 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3674 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3676 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3677 filter
= make_ssa_name (filter
, x
);
3678 gimple_call_set_lhs (x
, filter
);
3679 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3681 r
->u
.allowed
.label
= NULL
;
3682 x
= gimple_build_cond (EQ_EXPR
, filter
,
3683 build_int_cst (TREE_TYPE (filter
),
3684 r
->u
.allowed
.filter
),
3685 NULL_TREE
, NULL_TREE
);
3686 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3688 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3689 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3697 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3698 gsi_remove (&gsi
, true);
3703 execute_lower_eh_dispatch (void)
3707 bool redirected
= false;
3709 assign_filter_values ();
3711 FOR_EACH_BB_FN (bb
, cfun
)
3713 gimple last
= last_stmt (bb
);
3716 if (gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3718 redirected
|= lower_eh_dispatch (bb
, last
);
3719 flags
|= TODO_update_ssa_only_virtuals
;
3721 else if (gimple_code (last
) == GIMPLE_RESX
)
3723 if (stmt_can_throw_external (last
))
3724 optimize_clobbers (bb
);
3726 flags
|= sink_clobbers (bb
);
3731 delete_unreachable_blocks ();
3736 gate_lower_eh_dispatch (void)
3738 return cfun
->eh
->region_tree
!= NULL
;
3743 const pass_data pass_data_lower_eh_dispatch
=
3745 GIMPLE_PASS
, /* type */
3746 "ehdisp", /* name */
3747 OPTGROUP_NONE
, /* optinfo_flags */
3748 true, /* has_gate */
3749 true, /* has_execute */
3750 TV_TREE_EH
, /* tv_id */
3751 PROP_gimple_lcf
, /* properties_required */
3752 0, /* properties_provided */
3753 0, /* properties_destroyed */
3754 0, /* todo_flags_start */
3755 TODO_verify_flow
, /* todo_flags_finish */
3758 class pass_lower_eh_dispatch
: public gimple_opt_pass
3761 pass_lower_eh_dispatch (gcc::context
*ctxt
)
3762 : gimple_opt_pass (pass_data_lower_eh_dispatch
, ctxt
)
3765 /* opt_pass methods: */
3766 bool gate () { return gate_lower_eh_dispatch (); }
3767 unsigned int execute () { return execute_lower_eh_dispatch (); }
3769 }; // class pass_lower_eh_dispatch
3774 make_pass_lower_eh_dispatch (gcc::context
*ctxt
)
3776 return new pass_lower_eh_dispatch (ctxt
);
3779 /* Walk statements, see what regions and, optionally, landing pads
3780 are really referenced.
3782 Returns in R_REACHABLEP an sbitmap with bits set for reachable regions,
3783 and in LP_REACHABLE an sbitmap with bits set for reachable landing pads.
3785 Passing NULL for LP_REACHABLE is valid, in this case only reachable
3788 The caller is responsible for freeing the returned sbitmaps. */
3791 mark_reachable_handlers (sbitmap
*r_reachablep
, sbitmap
*lp_reachablep
)
3793 sbitmap r_reachable
, lp_reachable
;
3795 bool mark_landing_pads
= (lp_reachablep
!= NULL
);
3796 gcc_checking_assert (r_reachablep
!= NULL
);
3798 r_reachable
= sbitmap_alloc (cfun
->eh
->region_array
->length ());
3799 bitmap_clear (r_reachable
);
3800 *r_reachablep
= r_reachable
;
3802 if (mark_landing_pads
)
3804 lp_reachable
= sbitmap_alloc (cfun
->eh
->lp_array
->length ());
3805 bitmap_clear (lp_reachable
);
3806 *lp_reachablep
= lp_reachable
;
3809 lp_reachable
= NULL
;
3811 FOR_EACH_BB_FN (bb
, cfun
)
3813 gimple_stmt_iterator gsi
;
3815 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3817 gimple stmt
= gsi_stmt (gsi
);
3819 if (mark_landing_pads
)
3821 int lp_nr
= lookup_stmt_eh_lp (stmt
);
3823 /* Negative LP numbers are MUST_NOT_THROW regions which
3824 are not considered BB enders. */
3826 bitmap_set_bit (r_reachable
, -lp_nr
);
3828 /* Positive LP numbers are real landing pads, and BB enders. */
3831 gcc_assert (gsi_one_before_end_p (gsi
));
3832 eh_region region
= get_eh_region_from_lp_number (lp_nr
);
3833 bitmap_set_bit (r_reachable
, region
->index
);
3834 bitmap_set_bit (lp_reachable
, lp_nr
);
3838 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3839 switch (gimple_code (stmt
))
3842 bitmap_set_bit (r_reachable
, gimple_resx_region (stmt
));
3844 case GIMPLE_EH_DISPATCH
:
3845 bitmap_set_bit (r_reachable
, gimple_eh_dispatch_region (stmt
));
3854 /* Remove unreachable handlers and unreachable landing pads. */
3857 remove_unreachable_handlers (void)
3859 sbitmap r_reachable
, lp_reachable
;
3864 mark_reachable_handlers (&r_reachable
, &lp_reachable
);
3868 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3869 dump_eh_tree (dump_file
, cfun
);
3870 fprintf (dump_file
, "Reachable regions: ");
3871 dump_bitmap_file (dump_file
, r_reachable
);
3872 fprintf (dump_file
, "Reachable landing pads: ");
3873 dump_bitmap_file (dump_file
, lp_reachable
);
3878 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3879 if (region
&& !bitmap_bit_p (r_reachable
, region
->index
))
3881 "Removing unreachable region %d\n",
3885 remove_unreachable_eh_regions (r_reachable
);
3887 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3888 if (lp
&& !bitmap_bit_p (lp_reachable
, lp
->index
))
3892 "Removing unreachable landing pad %d\n",
3894 remove_eh_landing_pad (lp
);
3899 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3900 dump_eh_tree (dump_file
, cfun
);
3901 fprintf (dump_file
, "\n\n");
3904 sbitmap_free (r_reachable
);
3905 sbitmap_free (lp_reachable
);
3907 #ifdef ENABLE_CHECKING
3908 verify_eh_tree (cfun
);
3912 /* Remove unreachable handlers if any landing pads have been removed after
3913 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3916 maybe_remove_unreachable_handlers (void)
3921 if (cfun
->eh
== NULL
)
3924 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3925 if (lp
&& lp
->post_landing_pad
)
3927 if (label_to_block (lp
->post_landing_pad
) == NULL
)
3929 remove_unreachable_handlers ();
3935 /* Remove regions that do not have landing pads. This assumes
3936 that remove_unreachable_handlers has already been run, and
3937 that we've just manipulated the landing pads since then.
3939 Preserve regions with landing pads and regions that prevent
3940 exceptions from propagating further, even if these regions
3941 are not reachable. */
3944 remove_unreachable_handlers_no_lp (void)
3947 sbitmap r_reachable
;
3950 mark_reachable_handlers (&r_reachable
, /*lp_reachablep=*/NULL
);
3952 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3957 if (region
->landing_pads
!= NULL
3958 || region
->type
== ERT_MUST_NOT_THROW
)
3959 bitmap_set_bit (r_reachable
, region
->index
);
3962 && !bitmap_bit_p (r_reachable
, region
->index
))
3964 "Removing unreachable region %d\n",
3968 remove_unreachable_eh_regions (r_reachable
);
3970 sbitmap_free (r_reachable
);
3973 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3974 optimisticaly split all sorts of edges, including EH edges. The
3975 optimization passes in between may not have needed them; if not,
3976 we should undo the split.
3978 Recognize this case by having one EH edge incoming to the BB and
3979 one normal edge outgoing; BB should be empty apart from the
3980 post_landing_pad label.
3982 Note that this is slightly different from the empty handler case
3983 handled by cleanup_empty_eh, in that the actual handler may yet
3984 have actual code but the landing pad has been separated from the
3985 handler. As such, cleanup_empty_eh relies on this transformation
3986 having been done first. */
3989 unsplit_eh (eh_landing_pad lp
)
3991 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3992 gimple_stmt_iterator gsi
;
3995 /* Quickly check the edge counts on BB for singularity. */
3996 if (!single_pred_p (bb
) || !single_succ_p (bb
))
3998 e_in
= single_pred_edge (bb
);
3999 e_out
= single_succ_edge (bb
);
4001 /* Input edge must be EH and output edge must be normal. */
4002 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
4005 /* The block must be empty except for the labels and debug insns. */
4006 gsi
= gsi_after_labels (bb
);
4007 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4008 gsi_next_nondebug (&gsi
);
4009 if (!gsi_end_p (gsi
))
4012 /* The destination block must not already have a landing pad
4013 for a different region. */
4014 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4016 gimple stmt
= gsi_stmt (gsi
);
4020 if (gimple_code (stmt
) != GIMPLE_LABEL
)
4022 lab
= gimple_label_label (stmt
);
4023 lp_nr
= EH_LANDING_PAD_NR (lab
);
4024 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4028 /* The new destination block must not already be a destination of
4029 the source block, lest we merge fallthru and eh edges and get
4030 all sorts of confused. */
4031 if (find_edge (e_in
->src
, e_out
->dest
))
4034 /* ??? We can get degenerate phis due to cfg cleanups. I would have
4035 thought this should have been cleaned up by a phicprop pass, but
4036 that doesn't appear to handle virtuals. Propagate by hand. */
4037 if (!gimple_seq_empty_p (phi_nodes (bb
)))
4039 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); )
4041 gimple use_stmt
, phi
= gsi_stmt (gsi
);
4042 tree lhs
= gimple_phi_result (phi
);
4043 tree rhs
= gimple_phi_arg_def (phi
, 0);
4044 use_operand_p use_p
;
4045 imm_use_iterator iter
;
4047 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
4049 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
4050 SET_USE (use_p
, rhs
);
4053 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
4054 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
4056 remove_phi_node (&gsi
, true);
4060 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4061 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
4062 lp
->index
, e_out
->dest
->index
);
4064 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
4065 a successor edge, humor it. But do the real CFG change with the
4066 predecessor of E_OUT in order to preserve the ordering of arguments
4067 to the PHI nodes in E_OUT->DEST. */
4068 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
4069 redirect_edge_pred (e_out
, e_in
->src
);
4070 e_out
->flags
= e_in
->flags
;
4071 e_out
->probability
= e_in
->probability
;
4072 e_out
->count
= e_in
->count
;
4078 /* Examine each landing pad block and see if it matches unsplit_eh. */
4081 unsplit_all_eh (void)
4083 bool changed
= false;
4087 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4089 changed
|= unsplit_eh (lp
);
4094 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
4095 to OLD_BB to NEW_BB; return true on success, false on failure.
4097 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
4098 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
4099 Virtual PHIs may be deleted and marked for renaming. */
4102 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
4103 edge old_bb_out
, bool change_region
)
4105 gimple_stmt_iterator ngsi
, ogsi
;
4108 bitmap ophi_handled
;
4110 /* The destination block must not be a regular successor for any
4111 of the preds of the landing pad. Thus, avoid turning
4121 which CFG verification would choke on. See PR45172 and PR51089. */
4122 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4123 if (find_edge (e
->src
, new_bb
))
4126 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4127 redirect_edge_var_map_clear (e
);
4129 ophi_handled
= BITMAP_ALLOC (NULL
);
4131 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
4132 for the edges we're going to move. */
4133 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
4135 gimple ophi
, nphi
= gsi_stmt (ngsi
);
4138 nresult
= gimple_phi_result (nphi
);
4139 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
4141 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
4142 the source ssa_name. */
4144 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4146 ophi
= gsi_stmt (ogsi
);
4147 if (gimple_phi_result (ophi
) == nop
)
4152 /* If we did find the corresponding PHI, copy those inputs. */
4155 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
4156 if (!has_single_use (nop
))
4158 imm_use_iterator imm_iter
;
4159 use_operand_p use_p
;
4161 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
4163 if (!gimple_debug_bind_p (USE_STMT (use_p
))
4164 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
4165 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
4169 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
4170 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4175 if ((e
->flags
& EDGE_EH
) == 0)
4177 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
4178 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
4179 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
4182 /* If we didn't find the PHI, if it's a real variable or a VOP, we know
4183 from the fact that OLD_BB is tree_empty_eh_handler_p that the
4184 variable is unchanged from input to the block and we can simply
4185 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
4189 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
4190 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4191 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
4195 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
4196 we don't know what values from the other edges into NEW_BB to use. */
4197 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4199 gimple ophi
= gsi_stmt (ogsi
);
4200 tree oresult
= gimple_phi_result (ophi
);
4201 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
4205 /* Finally, move the edges and update the PHIs. */
4206 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
4207 if (e
->flags
& EDGE_EH
)
4209 /* ??? CFG manipluation routines do not try to update loop
4210 form on edge redirection. Do so manually here for now. */
4211 /* If we redirect a loop entry or latch edge that will either create
4212 a multiple entry loop or rotate the loop. If the loops merge
4213 we may have created a loop with multiple latches.
4214 All of this isn't easily fixed thus cancel the affected loop
4215 and mark the other loop as possibly having multiple latches. */
4217 && e
->dest
== e
->dest
->loop_father
->header
)
4219 e
->dest
->loop_father
->header
= NULL
;
4220 e
->dest
->loop_father
->latch
= NULL
;
4221 new_bb
->loop_father
->latch
= NULL
;
4222 loops_state_set (LOOPS_NEED_FIXUP
|LOOPS_MAY_HAVE_MULTIPLE_LATCHES
);
4224 redirect_eh_edge_1 (e
, new_bb
, change_region
);
4225 redirect_edge_succ (e
, new_bb
);
4226 flush_pending_stmts (e
);
4231 BITMAP_FREE (ophi_handled
);
4235 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4236 redirect_edge_var_map_clear (e
);
4237 BITMAP_FREE (ophi_handled
);
4241 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
4242 old region to NEW_REGION at BB. */
4245 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
4246 eh_landing_pad lp
, eh_region new_region
)
4248 gimple_stmt_iterator gsi
;
4251 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
4255 lp
->region
= new_region
;
4256 lp
->next_lp
= new_region
->landing_pads
;
4257 new_region
->landing_pads
= lp
;
4259 /* Delete the RESX that was matched within the empty handler block. */
4260 gsi
= gsi_last_bb (bb
);
4261 unlink_stmt_vdef (gsi_stmt (gsi
));
4262 gsi_remove (&gsi
, true);
4264 /* Clean up E_OUT for the fallthru. */
4265 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
4266 e_out
->probability
= REG_BR_PROB_BASE
;
4269 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
4270 unsplitting than unsplit_eh was prepared to handle, e.g. when
4271 multiple incoming edges and phis are involved. */
4274 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
4276 gimple_stmt_iterator gsi
;
4279 /* We really ought not have totally lost everything following
4280 a landing pad label. Given that BB is empty, there had better
4282 gcc_assert (e_out
!= NULL
);
4284 /* The destination block must not already have a landing pad
4285 for a different region. */
4287 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4289 gimple stmt
= gsi_stmt (gsi
);
4292 if (gimple_code (stmt
) != GIMPLE_LABEL
)
4294 lab
= gimple_label_label (stmt
);
4295 lp_nr
= EH_LANDING_PAD_NR (lab
);
4296 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4300 /* Attempt to move the PHIs into the successor block. */
4301 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
4303 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4305 "Unsplit EH landing pad %d to block %i "
4306 "(via cleanup_empty_eh).\n",
4307 lp
->index
, e_out
->dest
->index
);
4314 /* Return true if edge E_FIRST is part of an empty infinite loop
4315 or leads to such a loop through a series of single successor
4319 infinite_empty_loop_p (edge e_first
)
4321 bool inf_loop
= false;
4324 if (e_first
->dest
== e_first
->src
)
4327 e_first
->src
->aux
= (void *) 1;
4328 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
4330 gimple_stmt_iterator gsi
;
4336 e
->dest
->aux
= (void *) 1;
4337 gsi
= gsi_after_labels (e
->dest
);
4338 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4339 gsi_next_nondebug (&gsi
);
4340 if (!gsi_end_p (gsi
))
4343 e_first
->src
->aux
= NULL
;
4344 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
4345 e
->dest
->aux
= NULL
;
4350 /* Examine the block associated with LP to determine if it's an empty
4351 handler for its EH region. If so, attempt to redirect EH edges to
4352 an outer region. Return true the CFG was updated in any way. This
4353 is similar to jump forwarding, just across EH edges. */
4356 cleanup_empty_eh (eh_landing_pad lp
)
4358 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4359 gimple_stmt_iterator gsi
;
4361 eh_region new_region
;
4364 bool has_non_eh_pred
;
4368 /* There can be zero or one edges out of BB. This is the quickest test. */
4369 switch (EDGE_COUNT (bb
->succs
))
4375 e_out
= single_succ_edge (bb
);
4381 resx
= last_stmt (bb
);
4382 if (resx
&& is_gimple_resx (resx
))
4384 if (stmt_can_throw_external (resx
))
4385 optimize_clobbers (bb
);
4386 else if (sink_clobbers (bb
))
4390 gsi
= gsi_after_labels (bb
);
4392 /* Make sure to skip debug statements. */
4393 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4394 gsi_next_nondebug (&gsi
);
4396 /* If the block is totally empty, look for more unsplitting cases. */
4397 if (gsi_end_p (gsi
))
4399 /* For the degenerate case of an infinite loop bail out. */
4400 if (infinite_empty_loop_p (e_out
))
4403 return ret
| cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
4406 /* The block should consist only of a single RESX statement, modulo a
4407 preceding call to __builtin_stack_restore if there is no outgoing
4408 edge, since the call can be eliminated in this case. */
4409 resx
= gsi_stmt (gsi
);
4410 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
4413 resx
= gsi_stmt (gsi
);
4415 if (!is_gimple_resx (resx
))
4417 gcc_assert (gsi_one_before_end_p (gsi
));
4419 /* Determine if there are non-EH edges, or resx edges into the handler. */
4420 has_non_eh_pred
= false;
4421 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4422 if (!(e
->flags
& EDGE_EH
))
4423 has_non_eh_pred
= true;
4425 /* Find the handler that's outer of the empty handler by looking at
4426 where the RESX instruction was vectored. */
4427 new_lp_nr
= lookup_stmt_eh_lp (resx
);
4428 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
4430 /* If there's no destination region within the current function,
4431 redirection is trivial via removing the throwing statements from
4432 the EH region, removing the EH edges, and allowing the block
4433 to go unreachable. */
4434 if (new_region
== NULL
)
4436 gcc_assert (e_out
== NULL
);
4437 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4438 if (e
->flags
& EDGE_EH
)
4440 gimple stmt
= last_stmt (e
->src
);
4441 remove_stmt_from_eh_lp (stmt
);
4449 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4450 to handle the abort and allow the blocks to go unreachable. */
4451 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4453 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4454 if (e
->flags
& EDGE_EH
)
4456 gimple stmt
= last_stmt (e
->src
);
4457 remove_stmt_from_eh_lp (stmt
);
4458 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4466 /* Try to redirect the EH edges and merge the PHIs into the destination
4467 landing pad block. If the merge succeeds, we'll already have redirected
4468 all the EH edges. The handler itself will go unreachable if there were
4470 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4473 /* Finally, if all input edges are EH edges, then we can (potentially)
4474 reduce the number of transfers from the runtime by moving the landing
4475 pad from the original region to the new region. This is a win when
4476 we remove the last CLEANUP region along a particular exception
4477 propagation path. Since nothing changes except for the region with
4478 which the landing pad is associated, the PHI nodes do not need to be
4480 if (!has_non_eh_pred
)
4482 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4483 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4484 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4485 lp
->index
, new_region
->index
);
4487 /* ??? The CFG didn't change, but we may have rendered the
4488 old EH region unreachable. Trigger a cleanup there. */
4495 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4496 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4497 remove_eh_landing_pad (lp
);
4501 /* Do a post-order traversal of the EH region tree. Examine each
4502 post_landing_pad block and see if we can eliminate it as empty. */
4505 cleanup_all_empty_eh (void)
4507 bool changed
= false;
4511 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4513 changed
|= cleanup_empty_eh (lp
);
4518 /* Perform cleanups and lowering of exception handling
4519 1) cleanups regions with handlers doing nothing are optimized out
4520 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4521 3) Info about regions that are containing instructions, and regions
4522 reachable via local EH edges is collected
4523 4) Eh tree is pruned for regions no longer necessary.
4525 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4526 Unify those that have the same failure decl and locus.
4530 execute_cleanup_eh_1 (void)
4532 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4533 looking up unreachable landing pads. */
4534 remove_unreachable_handlers ();
4536 /* Watch out for the region tree vanishing due to all unreachable. */
4537 if (cfun
->eh
->region_tree
&& optimize
)
4539 bool changed
= false;
4541 changed
|= unsplit_all_eh ();
4542 changed
|= cleanup_all_empty_eh ();
4546 free_dominance_info (CDI_DOMINATORS
);
4547 free_dominance_info (CDI_POST_DOMINATORS
);
4549 /* We delayed all basic block deletion, as we may have performed
4550 cleanups on EH edges while non-EH edges were still present. */
4551 delete_unreachable_blocks ();
4553 /* We manipulated the landing pads. Remove any region that no
4554 longer has a landing pad. */
4555 remove_unreachable_handlers_no_lp ();
4557 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4565 execute_cleanup_eh (void)
4567 int ret
= execute_cleanup_eh_1 ();
4569 /* If the function no longer needs an EH personality routine
4570 clear it. This exposes cross-language inlining opportunities
4571 and avoids references to a never defined personality routine. */
4572 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4573 && function_needs_eh_personality (cfun
) != eh_personality_lang
)
4574 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4580 gate_cleanup_eh (void)
4582 return cfun
->eh
!= NULL
&& cfun
->eh
->region_tree
!= NULL
;
4587 const pass_data pass_data_cleanup_eh
=
4589 GIMPLE_PASS
, /* type */
4590 "ehcleanup", /* name */
4591 OPTGROUP_NONE
, /* optinfo_flags */
4592 true, /* has_gate */
4593 true, /* has_execute */
4594 TV_TREE_EH
, /* tv_id */
4595 PROP_gimple_lcf
, /* properties_required */
4596 0, /* properties_provided */
4597 0, /* properties_destroyed */
4598 0, /* todo_flags_start */
4599 TODO_verify_ssa
, /* todo_flags_finish */
4602 class pass_cleanup_eh
: public gimple_opt_pass
4605 pass_cleanup_eh (gcc::context
*ctxt
)
4606 : gimple_opt_pass (pass_data_cleanup_eh
, ctxt
)
4609 /* opt_pass methods: */
4610 opt_pass
* clone () { return new pass_cleanup_eh (m_ctxt
); }
4611 bool gate () { return gate_cleanup_eh (); }
4612 unsigned int execute () { return execute_cleanup_eh (); }
4614 }; // class pass_cleanup_eh
4619 make_pass_cleanup_eh (gcc::context
*ctxt
)
4621 return new pass_cleanup_eh (ctxt
);
4624 /* Verify that BB containing STMT as the last statement, has precisely the
4625 edge that make_eh_edges would create. */
4628 verify_eh_edges (gimple stmt
)
4630 basic_block bb
= gimple_bb (stmt
);
4631 eh_landing_pad lp
= NULL
;
4636 lp_nr
= lookup_stmt_eh_lp (stmt
);
4638 lp
= get_eh_landing_pad_from_number (lp_nr
);
4641 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4643 if (e
->flags
& EDGE_EH
)
4647 error ("BB %i has multiple EH edges", bb
->index
);
4659 error ("BB %i can not throw but has an EH edge", bb
->index
);
4665 if (!stmt_could_throw_p (stmt
))
4667 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4671 if (eh_edge
== NULL
)
4673 error ("BB %i is missing an EH edge", bb
->index
);
4677 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
4679 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4686 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4689 verify_eh_dispatch_edge (gimple stmt
)
4693 basic_block src
, dst
;
4694 bool want_fallthru
= true;
4698 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4699 src
= gimple_bb (stmt
);
4701 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4702 gcc_assert (e
->aux
== NULL
);
4707 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4709 dst
= label_to_block (c
->label
);
4710 e
= find_edge (src
, dst
);
4713 error ("BB %i is missing an edge", src
->index
);
4718 /* A catch-all handler doesn't have a fallthru. */
4719 if (c
->type_list
== NULL
)
4721 want_fallthru
= false;
4727 case ERT_ALLOWED_EXCEPTIONS
:
4728 dst
= label_to_block (r
->u
.allowed
.label
);
4729 e
= find_edge (src
, dst
);
4732 error ("BB %i is missing an edge", src
->index
);
4743 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4745 if (e
->flags
& EDGE_FALLTHRU
)
4747 if (fall_edge
!= NULL
)
4749 error ("BB %i too many fallthru edges", src
->index
);
4758 error ("BB %i has incorrect edge", src
->index
);
4762 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4764 error ("BB %i has incorrect fallthru edge", src
->index
);