1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
29 #include "pointer-set.h"
30 #include "tree-flow.h"
31 #include "tree-inline.h"
32 #include "tree-pass.h"
33 #include "langhooks.h"
35 #include "diagnostic-core.h"
40 /* In some instances a tree and a gimple need to be stored in a same table,
41 i.e. in hash tables. This is a structure to do this. */
42 typedef union {tree
*tp
; tree t
; gimple g
;} treemple
;
44 /* Nonzero if we are using EH to handle cleanups. */
45 static int using_eh_for_cleanups_p
= 0;
48 using_eh_for_cleanups (void)
50 using_eh_for_cleanups_p
= 1;
53 /* Misc functions used in this file. */
55 /* Remember and lookup EH landing pad data for arbitrary statements.
56 Really this means any statement that could_throw_p. We could
57 stuff this information into the stmt_ann data structure, but:
59 (1) We absolutely rely on this information being kept until
60 we get to rtl. Once we're done with lowering here, if we lose
61 the information there's no way to recover it!
63 (2) There are many more statements that *cannot* throw as
64 compared to those that can. We should be saving some amount
65 of space by only allocating memory for those that can throw. */
67 /* Add statement T in function IFUN to landing pad NUM. */
70 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple t
, int num
)
72 struct throw_stmt_node
*n
;
75 gcc_assert (num
!= 0);
77 n
= ggc_alloc_throw_stmt_node ();
81 if (!get_eh_throw_stmt_table (ifun
))
82 set_eh_throw_stmt_table (ifun
, htab_create_ggc (31, struct_ptr_hash
,
86 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), n
, INSERT
);
91 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
94 add_stmt_to_eh_lp (gimple t
, int num
)
96 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
99 /* Add statement T to the single EH landing pad in REGION. */
102 record_stmt_eh_region (eh_region region
, gimple t
)
106 if (region
->type
== ERT_MUST_NOT_THROW
)
107 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
110 eh_landing_pad lp
= region
->landing_pads
;
112 lp
= gen_eh_landing_pad (region
);
114 gcc_assert (lp
->next_lp
== NULL
);
115 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
120 /* Remove statement T in function IFUN from its EH landing pad. */
123 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple t
)
125 struct throw_stmt_node dummy
;
128 if (!get_eh_throw_stmt_table (ifun
))
132 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), &dummy
,
136 htab_clear_slot (get_eh_throw_stmt_table (ifun
), slot
);
144 /* Remove statement T in the current function (cfun) from its
148 remove_stmt_from_eh_lp (gimple t
)
150 return remove_stmt_from_eh_lp_fn (cfun
, t
);
153 /* Determine if statement T is inside an EH region in function IFUN.
154 Positive numbers indicate a landing pad index; negative numbers
155 indicate a MUST_NOT_THROW region index; zero indicates that the
156 statement is not recorded in the region table. */
159 lookup_stmt_eh_lp_fn (struct function
*ifun
, gimple t
)
161 struct throw_stmt_node
*p
, n
;
163 if (ifun
->eh
->throw_stmt_table
== NULL
)
167 p
= (struct throw_stmt_node
*) htab_find (ifun
->eh
->throw_stmt_table
, &n
);
168 return p
? p
->lp_nr
: 0;
171 /* Likewise, but always use the current function. */
174 lookup_stmt_eh_lp (gimple t
)
176 /* We can get called from initialized data when -fnon-call-exceptions
177 is on; prevent crash. */
180 return lookup_stmt_eh_lp_fn (cfun
, t
);
183 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
184 nodes and LABEL_DECL nodes. We will use this during the second phase to
185 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
187 struct finally_tree_node
189 /* When storing a GIMPLE_TRY, we have to record a gimple. However
190 when deciding whether a GOTO to a certain LABEL_DECL (which is a
191 tree) leaves the TRY block, its necessary to record a tree in
192 this field. Thus a treemple is used. */
197 /* Note that this table is *not* marked GTY. It is short-lived. */
198 static htab_t finally_tree
;
201 record_in_finally_tree (treemple child
, gimple parent
)
203 struct finally_tree_node
*n
;
206 n
= XNEW (struct finally_tree_node
);
210 slot
= htab_find_slot (finally_tree
, n
, INSERT
);
216 collect_finally_tree (gimple stmt
, gimple region
);
218 /* Go through the gimple sequence. Works with collect_finally_tree to
219 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
222 collect_finally_tree_1 (gimple_seq seq
, gimple region
)
224 gimple_stmt_iterator gsi
;
226 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
227 collect_finally_tree (gsi_stmt (gsi
), region
);
231 collect_finally_tree (gimple stmt
, gimple region
)
235 switch (gimple_code (stmt
))
238 temp
.t
= gimple_label_label (stmt
);
239 record_in_finally_tree (temp
, region
);
243 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
246 record_in_finally_tree (temp
, region
);
247 collect_finally_tree_1 (gimple_try_eval (stmt
), stmt
);
248 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
250 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
252 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
253 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
258 collect_finally_tree_1 (gimple_catch_handler (stmt
), region
);
261 case GIMPLE_EH_FILTER
:
262 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
266 collect_finally_tree_1 (gimple_eh_else_n_body (stmt
), region
);
267 collect_finally_tree_1 (gimple_eh_else_e_body (stmt
), region
);
271 /* A type, a decl, or some kind of statement that we're not
272 interested in. Don't walk them. */
278 /* Use the finally tree to determine if a jump from START to TARGET
279 would leave the try_finally node that START lives in. */
282 outside_finally_tree (treemple start
, gimple target
)
284 struct finally_tree_node n
, *p
;
289 p
= (struct finally_tree_node
*) htab_find (finally_tree
, &n
);
294 while (start
.g
!= target
);
299 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
300 nodes into a set of gotos, magic labels, and eh regions.
301 The eh region creation is straight-forward, but frobbing all the gotos
302 and such into shape isn't. */
304 /* The sequence into which we record all EH stuff. This will be
305 placed at the end of the function when we're all done. */
306 static gimple_seq eh_seq
;
308 /* Record whether an EH region contains something that can throw,
309 indexed by EH region number. */
310 static bitmap eh_region_may_contain_throw_map
;
312 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
313 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
314 The idea is to record a gimple statement for everything except for
315 the conditionals, which get their labels recorded. Since labels are
316 of type 'tree', we need this node to store both gimple and tree
317 objects. REPL_STMT is the sequence used to replace the goto/return
318 statement. CONT_STMT is used to store the statement that allows
319 the return/goto to jump to the original destination. */
321 struct goto_queue_node
324 gimple_seq repl_stmt
;
327 /* This is used when index >= 0 to indicate that stmt is a label (as
328 opposed to a goto stmt). */
332 /* State of the world while lowering. */
336 /* What's "current" while constructing the eh region tree. These
337 correspond to variables of the same name in cfun->eh, which we
338 don't have easy access to. */
339 eh_region cur_region
;
341 /* What's "current" for the purposes of __builtin_eh_pointer. For
342 a CATCH, this is the associated TRY. For an EH_FILTER, this is
343 the associated ALLOWED_EXCEPTIONS, etc. */
344 eh_region ehp_region
;
346 /* Processing of TRY_FINALLY requires a bit more state. This is
347 split out into a separate structure so that we don't have to
348 copy so much when processing other nodes. */
349 struct leh_tf_state
*tf
;
354 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
355 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
356 this so that outside_finally_tree can reliably reference the tree used
357 in the collect_finally_tree data structures. */
358 gimple try_finally_expr
;
361 /* While lowering a top_p usually it is expanded into multiple statements,
362 thus we need the following field to store them. */
363 gimple_seq top_p_seq
;
365 /* The state outside this try_finally node. */
366 struct leh_state
*outer
;
368 /* The exception region created for it. */
371 /* The goto queue. */
372 struct goto_queue_node
*goto_queue
;
373 size_t goto_queue_size
;
374 size_t goto_queue_active
;
376 /* Pointer map to help in searching goto_queue when it is large. */
377 struct pointer_map_t
*goto_queue_map
;
379 /* The set of unique labels seen as entries in the goto queue. */
380 VEC(tree
,heap
) *dest_array
;
382 /* A label to be added at the end of the completed transformed
383 sequence. It will be set if may_fallthru was true *at one time*,
384 though subsequent transformations may have cleared that flag. */
387 /* True if it is possible to fall out the bottom of the try block.
388 Cleared if the fallthru is converted to a goto. */
391 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
394 /* True if the finally block can receive an exception edge.
395 Cleared if the exception case is handled by code duplication. */
399 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gimple
);
401 /* Search for STMT in the goto queue. Return the replacement,
402 or null if the statement isn't in the queue. */
404 #define LARGE_GOTO_QUEUE 20
406 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*seq
);
409 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
414 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
416 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
417 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
418 return tf
->goto_queue
[i
].repl_stmt
;
422 /* If we have a large number of entries in the goto_queue, create a
423 pointer map and use that for searching. */
425 if (!tf
->goto_queue_map
)
427 tf
->goto_queue_map
= pointer_map_create ();
428 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
430 slot
= pointer_map_insert (tf
->goto_queue_map
,
431 tf
->goto_queue
[i
].stmt
.g
);
432 gcc_assert (*slot
== NULL
);
433 *slot
= &tf
->goto_queue
[i
];
437 slot
= pointer_map_contains (tf
->goto_queue_map
, stmt
.g
);
439 return (((struct goto_queue_node
*) *slot
)->repl_stmt
);
444 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
445 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
446 then we can just splat it in, otherwise we add the new stmts immediately
447 after the GIMPLE_COND and redirect. */
450 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
451 gimple_stmt_iterator
*gsi
)
456 location_t loc
= gimple_location (gsi_stmt (*gsi
));
459 new_seq
= find_goto_replacement (tf
, temp
);
463 if (gimple_seq_singleton_p (new_seq
)
464 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
466 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
470 label
= create_artificial_label (loc
);
471 /* Set the new label for the GIMPLE_COND */
474 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
475 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
478 /* The real work of replace_goto_queue. Returns with TSI updated to
479 point to the next statement. */
481 static void replace_goto_queue_stmt_list (gimple_seq
*, struct leh_tf_state
*);
484 replace_goto_queue_1 (gimple stmt
, struct leh_tf_state
*tf
,
485 gimple_stmt_iterator
*gsi
)
491 switch (gimple_code (stmt
))
496 seq
= find_goto_replacement (tf
, temp
);
499 gsi_insert_seq_before (gsi
, gimple_seq_copy (seq
), GSI_SAME_STMT
);
500 gsi_remove (gsi
, false);
506 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
507 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
511 replace_goto_queue_stmt_list (gimple_try_eval_ptr (stmt
), tf
);
512 replace_goto_queue_stmt_list (gimple_try_cleanup_ptr (stmt
), tf
);
515 replace_goto_queue_stmt_list (gimple_catch_handler_ptr (stmt
), tf
);
517 case GIMPLE_EH_FILTER
:
518 replace_goto_queue_stmt_list (gimple_eh_filter_failure_ptr (stmt
), tf
);
521 replace_goto_queue_stmt_list (gimple_eh_else_n_body_ptr (stmt
), tf
);
522 replace_goto_queue_stmt_list (gimple_eh_else_e_body_ptr (stmt
), tf
);
526 /* These won't have gotos in them. */
533 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
536 replace_goto_queue_stmt_list (gimple_seq
*seq
, struct leh_tf_state
*tf
)
538 gimple_stmt_iterator gsi
= gsi_start (*seq
);
540 while (!gsi_end_p (gsi
))
541 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
544 /* Replace all goto queue members. */
547 replace_goto_queue (struct leh_tf_state
*tf
)
549 if (tf
->goto_queue_active
== 0)
551 replace_goto_queue_stmt_list (&tf
->top_p_seq
, tf
);
552 replace_goto_queue_stmt_list (&eh_seq
, tf
);
555 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
556 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
560 record_in_goto_queue (struct leh_tf_state
*tf
,
566 struct goto_queue_node
*q
;
568 gcc_assert (!tf
->goto_queue_map
);
570 active
= tf
->goto_queue_active
;
571 size
= tf
->goto_queue_size
;
574 size
= (size
? size
* 2 : 32);
575 tf
->goto_queue_size
= size
;
577 = XRESIZEVEC (struct goto_queue_node
, tf
->goto_queue
, size
);
580 q
= &tf
->goto_queue
[active
];
581 tf
->goto_queue_active
= active
+ 1;
583 memset (q
, 0, sizeof (*q
));
586 q
->is_label
= is_label
;
589 /* Record the LABEL label in the goto queue contained in TF.
593 record_in_goto_queue_label (struct leh_tf_state
*tf
, treemple stmt
, tree label
)
596 treemple temp
, new_stmt
;
601 /* Computed and non-local gotos do not get processed. Given
602 their nature we can neither tell whether we've escaped the
603 finally block nor redirect them if we knew. */
604 if (TREE_CODE (label
) != LABEL_DECL
)
607 /* No need to record gotos that don't leave the try block. */
609 if (!outside_finally_tree (temp
, tf
->try_finally_expr
))
612 if (! tf
->dest_array
)
614 tf
->dest_array
= VEC_alloc (tree
, heap
, 10);
615 VEC_quick_push (tree
, tf
->dest_array
, label
);
620 int n
= VEC_length (tree
, tf
->dest_array
);
621 for (index
= 0; index
< n
; ++index
)
622 if (VEC_index (tree
, tf
->dest_array
, index
) == label
)
625 VEC_safe_push (tree
, heap
, tf
->dest_array
, label
);
628 /* In the case of a GOTO we want to record the destination label,
629 since with a GIMPLE_COND we have an easy access to the then/else
632 record_in_goto_queue (tf
, new_stmt
, index
, true);
635 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
636 node, and if so record that fact in the goto queue associated with that
640 maybe_record_in_goto_queue (struct leh_state
*state
, gimple stmt
)
642 struct leh_tf_state
*tf
= state
->tf
;
648 switch (gimple_code (stmt
))
651 new_stmt
.tp
= gimple_op_ptr (stmt
, 2);
652 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_true_label (stmt
));
653 new_stmt
.tp
= gimple_op_ptr (stmt
, 3);
654 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_false_label (stmt
));
658 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
));
662 tf
->may_return
= true;
664 record_in_goto_queue (tf
, new_stmt
, -1, false);
673 #ifdef ENABLE_CHECKING
674 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
675 was in fact structured, and we've not yet done jump threading, then none
676 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
679 verify_norecord_switch_expr (struct leh_state
*state
, gimple switch_expr
)
681 struct leh_tf_state
*tf
= state
->tf
;
687 n
= gimple_switch_num_labels (switch_expr
);
689 for (i
= 0; i
< n
; ++i
)
692 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
694 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
698 #define verify_norecord_switch_expr(state, switch_expr)
701 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
702 non-null, insert it before the new branch. */
705 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
)
709 /* In the case of a return, the queue node must be a gimple statement. */
710 gcc_assert (!q
->is_label
);
712 /* Note that the return value may have already been computed, e.g.,
725 should return 0, not 1. We don't have to do anything to make
726 this happens because the return value has been placed in the
727 RESULT_DECL already. */
729 q
->cont_stmt
= q
->stmt
.g
;
732 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
734 x
= gimple_build_goto (finlab
);
735 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
738 /* Similar, but easier, for GIMPLE_GOTO. */
741 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
742 struct leh_tf_state
*tf
)
746 gcc_assert (q
->is_label
);
748 q
->cont_stmt
= gimple_build_goto (VEC_index (tree
, tf
->dest_array
, q
->index
));
751 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
753 x
= gimple_build_goto (finlab
);
754 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
757 /* Emit a standard landing pad sequence into SEQ for REGION. */
760 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
762 eh_landing_pad lp
= region
->landing_pads
;
766 lp
= gen_eh_landing_pad (region
);
768 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
769 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
771 x
= gimple_build_label (lp
->post_landing_pad
);
772 gimple_seq_add_stmt (seq
, x
);
775 /* Emit a RESX statement into SEQ for REGION. */
778 emit_resx (gimple_seq
*seq
, eh_region region
)
780 gimple x
= gimple_build_resx (region
->index
);
781 gimple_seq_add_stmt (seq
, x
);
783 record_stmt_eh_region (region
->outer
, x
);
786 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
789 emit_eh_dispatch (gimple_seq
*seq
, eh_region region
)
791 gimple x
= gimple_build_eh_dispatch (region
->index
);
792 gimple_seq_add_stmt (seq
, x
);
795 /* Note that the current EH region may contain a throw, or a
796 call to a function which itself may contain a throw. */
799 note_eh_region_may_contain_throw (eh_region region
)
801 while (bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
))
803 if (region
->type
== ERT_MUST_NOT_THROW
)
805 region
= region
->outer
;
811 /* Check if REGION has been marked as containing a throw. If REGION is
812 NULL, this predicate is false. */
815 eh_region_may_contain_throw (eh_region r
)
817 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
820 /* We want to transform
821 try { body; } catch { stuff; }
831 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
832 should be placed before the second operand, or NULL. OVER is
833 an existing label that should be put at the exit, or NULL. */
836 frob_into_branch_around (gimple tp
, eh_region region
, tree over
)
839 gimple_seq cleanup
, result
;
840 location_t loc
= gimple_location (tp
);
842 cleanup
= gimple_try_cleanup (tp
);
843 result
= gimple_try_eval (tp
);
846 emit_post_landing_pad (&eh_seq
, region
);
848 if (gimple_seq_may_fallthru (cleanup
))
851 over
= create_artificial_label (loc
);
852 x
= gimple_build_goto (over
);
853 gimple_seq_add_stmt (&cleanup
, x
);
855 gimple_seq_add_seq (&eh_seq
, cleanup
);
859 x
= gimple_build_label (over
);
860 gimple_seq_add_stmt (&result
, x
);
865 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
866 Make sure to record all new labels found. */
869 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
)
871 gimple region
= NULL
;
874 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
877 region
= outer_state
->tf
->try_finally_expr
;
878 collect_finally_tree_1 (new_seq
, region
);
883 /* A subroutine of lower_try_finally. Create a fallthru label for
884 the given try_finally state. The only tricky bit here is that
885 we have to make sure to record the label in our outer context. */
888 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
890 tree label
= tf
->fallthru_label
;
895 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
896 tf
->fallthru_label
= label
;
900 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
906 /* A subroutine of lower_try_finally. If FINALLY consits of a
907 GIMPLE_EH_ELSE node, return it. */
910 get_eh_else (gimple_seq finally
)
912 gimple x
= gimple_seq_first_stmt (finally
);
913 if (gimple_code (x
) == GIMPLE_EH_ELSE
)
915 gcc_assert (gimple_seq_singleton_p (finally
));
921 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
922 langhook returns non-null, then the language requires that the exception
923 path out of a try_finally be treated specially. To wit: the code within
924 the finally block may not itself throw an exception. We have two choices
925 here. First we can duplicate the finally block and wrap it in a
926 must_not_throw region. Second, we can generate code like
931 if (fintmp == eh_edge)
932 protect_cleanup_actions;
935 where "fintmp" is the temporary used in the switch statement generation
936 alternative considered below. For the nonce, we always choose the first
939 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
942 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
943 struct leh_state
*this_state
,
944 struct leh_tf_state
*tf
)
946 tree protect_cleanup_actions
;
947 gimple_stmt_iterator gsi
;
948 bool finally_may_fallthru
;
952 /* First check for nothing to do. */
953 if (lang_hooks
.eh_protect_cleanup_actions
== NULL
)
955 protect_cleanup_actions
= lang_hooks
.eh_protect_cleanup_actions ();
956 if (protect_cleanup_actions
== NULL
)
959 finally
= gimple_try_cleanup (tf
->top_p
);
960 eh_else
= get_eh_else (finally
);
962 /* Duplicate the FINALLY block. Only need to do this for try-finally,
963 and not for cleanups. If we've got an EH_ELSE, extract it now. */
966 finally
= gimple_eh_else_e_body (eh_else
);
967 gimple_try_set_cleanup (tf
->top_p
, gimple_eh_else_n_body (eh_else
));
970 finally
= lower_try_finally_dup_block (finally
, outer_state
);
971 finally_may_fallthru
= gimple_seq_may_fallthru (finally
);
973 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
974 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
975 to be in an enclosing scope, but needs to be implemented at this level
976 to avoid a nesting violation (see wrap_temporary_cleanups in
977 cp/decl.c). Since it's logically at an outer level, we should call
978 terminate before we get to it, so strip it away before adding the
979 MUST_NOT_THROW filter. */
980 gsi
= gsi_start (finally
);
982 if (gimple_code (x
) == GIMPLE_TRY
983 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
984 && gimple_try_catch_is_cleanup (x
))
986 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
987 gsi_remove (&gsi
, false);
990 /* Wrap the block with protect_cleanup_actions as the action. */
991 x
= gimple_build_eh_must_not_throw (protect_cleanup_actions
);
992 x
= gimple_build_try (finally
, gimple_seq_alloc_with_stmt (x
),
994 finally
= lower_eh_must_not_throw (outer_state
, x
);
996 /* Drop all of this into the exception sequence. */
997 emit_post_landing_pad (&eh_seq
, tf
->region
);
998 gimple_seq_add_seq (&eh_seq
, finally
);
999 if (finally_may_fallthru
)
1000 emit_resx (&eh_seq
, tf
->region
);
1002 /* Having now been handled, EH isn't to be considered with
1003 the rest of the outgoing edges. */
1004 tf
->may_throw
= false;
1007 /* A subroutine of lower_try_finally. We have determined that there is
1008 no fallthru edge out of the finally block. This means that there is
1009 no outgoing edge corresponding to any incoming edge. Restructure the
1010 try_finally node for this special case. */
1013 lower_try_finally_nofallthru (struct leh_state
*state
,
1014 struct leh_tf_state
*tf
)
1019 struct goto_queue_node
*q
, *qe
;
1021 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1023 /* We expect that tf->top_p is a GIMPLE_TRY. */
1024 finally
= gimple_try_cleanup (tf
->top_p
);
1025 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1027 x
= gimple_build_label (lab
);
1028 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1031 qe
= q
+ tf
->goto_queue_active
;
1034 do_return_redirection (q
, lab
, NULL
);
1036 do_goto_redirection (q
, lab
, NULL
, tf
);
1038 replace_goto_queue (tf
);
1040 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1041 eh_else
= get_eh_else (finally
);
1044 finally
= gimple_eh_else_n_body (eh_else
);
1045 lower_eh_constructs_1 (state
, &finally
);
1046 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1050 finally
= gimple_eh_else_e_body (eh_else
);
1051 lower_eh_constructs_1 (state
, &finally
);
1053 emit_post_landing_pad (&eh_seq
, tf
->region
);
1054 gimple_seq_add_seq (&eh_seq
, finally
);
1059 lower_eh_constructs_1 (state
, &finally
);
1060 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1064 emit_post_landing_pad (&eh_seq
, tf
->region
);
1066 x
= gimple_build_goto (lab
);
1067 gimple_seq_add_stmt (&eh_seq
, x
);
1072 /* A subroutine of lower_try_finally. We have determined that there is
1073 exactly one destination of the finally block. Restructure the
1074 try_finally node for this special case. */
1077 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1079 struct goto_queue_node
*q
, *qe
;
1083 location_t loc
= gimple_location (tf
->try_finally_expr
);
1085 finally
= gimple_try_cleanup (tf
->top_p
);
1086 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1088 /* Since there's only one destination, and the destination edge can only
1089 either be EH or non-EH, that implies that all of our incoming edges
1090 are of the same type. Therefore we can lower EH_ELSE immediately. */
1091 x
= get_eh_else (finally
);
1095 finally
= gimple_eh_else_e_body (x
);
1097 finally
= gimple_eh_else_n_body (x
);
1100 lower_eh_constructs_1 (state
, &finally
);
1104 /* Only reachable via the exception edge. Add the given label to
1105 the head of the FINALLY block. Append a RESX at the end. */
1106 emit_post_landing_pad (&eh_seq
, tf
->region
);
1107 gimple_seq_add_seq (&eh_seq
, finally
);
1108 emit_resx (&eh_seq
, tf
->region
);
1112 if (tf
->may_fallthru
)
1114 /* Only reachable via the fallthru edge. Do nothing but let
1115 the two blocks run together; we'll fall out the bottom. */
1116 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1120 finally_label
= create_artificial_label (loc
);
1121 x
= gimple_build_label (finally_label
);
1122 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1124 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1127 qe
= q
+ tf
->goto_queue_active
;
1131 /* Reachable by return expressions only. Redirect them. */
1133 do_return_redirection (q
, finally_label
, NULL
);
1134 replace_goto_queue (tf
);
1138 /* Reachable by goto expressions only. Redirect them. */
1140 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1141 replace_goto_queue (tf
);
1143 if (VEC_index (tree
, tf
->dest_array
, 0) == tf
->fallthru_label
)
1145 /* Reachable by goto to fallthru label only. Redirect it
1146 to the new label (already created, sadly), and do not
1147 emit the final branch out, or the fallthru label. */
1148 tf
->fallthru_label
= NULL
;
1153 /* Place the original return/goto to the original destination
1154 immediately after the finally block. */
1155 x
= tf
->goto_queue
[0].cont_stmt
;
1156 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1157 maybe_record_in_goto_queue (state
, x
);
1160 /* A subroutine of lower_try_finally. There are multiple edges incoming
1161 and outgoing from the finally block. Implement this by duplicating the
1162 finally block for every destination. */
1165 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1168 gimple_seq new_stmt
;
1172 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1174 finally
= gimple_try_cleanup (tf
->top_p
);
1176 /* Notice EH_ELSE, and simplify some of the remaining code
1177 by considering FINALLY to be the normal return path only. */
1178 eh_else
= get_eh_else (finally
);
1180 finally
= gimple_eh_else_n_body (eh_else
);
1182 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1185 if (tf
->may_fallthru
)
1187 seq
= lower_try_finally_dup_block (finally
, state
);
1188 lower_eh_constructs_1 (state
, &seq
);
1189 gimple_seq_add_seq (&new_stmt
, seq
);
1191 tmp
= lower_try_finally_fallthru_label (tf
);
1192 x
= gimple_build_goto (tmp
);
1193 gimple_seq_add_stmt (&new_stmt
, x
);
1198 /* We don't need to copy the EH path of EH_ELSE,
1199 since it is only emitted once. */
1201 seq
= gimple_eh_else_e_body (eh_else
);
1203 seq
= lower_try_finally_dup_block (finally
, state
);
1204 lower_eh_constructs_1 (state
, &seq
);
1206 emit_post_landing_pad (&eh_seq
, tf
->region
);
1207 gimple_seq_add_seq (&eh_seq
, seq
);
1208 emit_resx (&eh_seq
, tf
->region
);
1213 struct goto_queue_node
*q
, *qe
;
1214 int return_index
, index
;
1217 struct goto_queue_node
*q
;
1221 return_index
= VEC_length (tree
, tf
->dest_array
);
1222 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1225 qe
= q
+ tf
->goto_queue_active
;
1228 index
= q
->index
< 0 ? return_index
: q
->index
;
1230 if (!labels
[index
].q
)
1231 labels
[index
].q
= q
;
1234 for (index
= 0; index
< return_index
+ 1; index
++)
1238 q
= labels
[index
].q
;
1242 lab
= labels
[index
].label
1243 = create_artificial_label (tf_loc
);
1245 if (index
== return_index
)
1246 do_return_redirection (q
, lab
, NULL
);
1248 do_goto_redirection (q
, lab
, NULL
, tf
);
1250 x
= gimple_build_label (lab
);
1251 gimple_seq_add_stmt (&new_stmt
, x
);
1253 seq
= lower_try_finally_dup_block (finally
, state
);
1254 lower_eh_constructs_1 (state
, &seq
);
1255 gimple_seq_add_seq (&new_stmt
, seq
);
1257 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1258 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1261 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1265 index
= q
->index
< 0 ? return_index
: q
->index
;
1267 if (labels
[index
].q
== q
)
1270 lab
= labels
[index
].label
;
1272 if (index
== return_index
)
1273 do_return_redirection (q
, lab
, NULL
);
1275 do_goto_redirection (q
, lab
, NULL
, tf
);
1278 replace_goto_queue (tf
);
1282 /* Need to link new stmts after running replace_goto_queue due
1283 to not wanting to process the same goto stmts twice. */
1284 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1287 /* A subroutine of lower_try_finally. There are multiple edges incoming
1288 and outgoing from the finally block. Implement this by instrumenting
1289 each incoming edge and creating a switch statement at the end of the
1290 finally block that branches to the appropriate destination. */
1293 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1295 struct goto_queue_node
*q
, *qe
;
1296 tree finally_tmp
, finally_label
;
1297 int return_index
, eh_index
, fallthru_index
;
1298 int nlabels
, ndests
, j
, last_case_index
;
1300 VEC (tree
,heap
) *case_label_vec
;
1301 gimple_seq switch_body
= NULL
;
1306 struct pointer_map_t
*cont_map
= NULL
;
1307 /* The location of the TRY_FINALLY stmt. */
1308 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1309 /* The location of the finally block. */
1310 location_t finally_loc
;
1312 finally
= gimple_try_cleanup (tf
->top_p
);
1313 eh_else
= get_eh_else (finally
);
1315 /* Mash the TRY block to the head of the chain. */
1316 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1318 /* The location of the finally is either the last stmt in the finally
1319 block or the location of the TRY_FINALLY itself. */
1320 x
= gimple_seq_last_stmt (finally
);
1321 finally_loc
= x
? gimple_location (x
) : tf_loc
;
1323 /* Lower the finally block itself. */
1324 lower_eh_constructs_1 (state
, &finally
);
1326 /* Prepare for switch statement generation. */
1327 nlabels
= VEC_length (tree
, tf
->dest_array
);
1328 return_index
= nlabels
;
1329 eh_index
= return_index
+ tf
->may_return
;
1330 fallthru_index
= eh_index
+ (tf
->may_throw
&& !eh_else
);
1331 ndests
= fallthru_index
+ tf
->may_fallthru
;
1333 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1334 finally_label
= create_artificial_label (finally_loc
);
1336 /* We use VEC_quick_push on case_label_vec throughout this function,
1337 since we know the size in advance and allocate precisely as muce
1339 case_label_vec
= VEC_alloc (tree
, heap
, ndests
);
1341 last_case_index
= 0;
1343 /* Begin inserting code for getting to the finally block. Things
1344 are done in this order to correspond to the sequence the code is
1347 if (tf
->may_fallthru
)
1349 x
= gimple_build_assign (finally_tmp
,
1350 build_int_cst (integer_type_node
,
1352 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1354 tmp
= build_int_cst (integer_type_node
, fallthru_index
);
1355 last_case
= build_case_label (tmp
, NULL
,
1356 create_artificial_label (tf_loc
));
1357 VEC_quick_push (tree
, case_label_vec
, last_case
);
1360 x
= gimple_build_label (CASE_LABEL (last_case
));
1361 gimple_seq_add_stmt (&switch_body
, x
);
1363 tmp
= lower_try_finally_fallthru_label (tf
);
1364 x
= gimple_build_goto (tmp
);
1365 gimple_seq_add_stmt (&switch_body
, x
);
1368 /* For EH_ELSE, emit the exception path (plus resx) now, then
1369 subsequently we only need consider the normal path. */
1374 finally
= gimple_eh_else_e_body (eh_else
);
1375 lower_eh_constructs_1 (state
, &finally
);
1377 emit_post_landing_pad (&eh_seq
, tf
->region
);
1378 gimple_seq_add_seq (&eh_seq
, finally
);
1379 emit_resx (&eh_seq
, tf
->region
);
1382 finally
= gimple_eh_else_n_body (eh_else
);
1384 else if (tf
->may_throw
)
1386 emit_post_landing_pad (&eh_seq
, tf
->region
);
1388 x
= gimple_build_assign (finally_tmp
,
1389 build_int_cst (integer_type_node
, eh_index
));
1390 gimple_seq_add_stmt (&eh_seq
, x
);
1392 x
= gimple_build_goto (finally_label
);
1393 gimple_seq_add_stmt (&eh_seq
, x
);
1395 tmp
= build_int_cst (integer_type_node
, eh_index
);
1396 last_case
= build_case_label (tmp
, NULL
,
1397 create_artificial_label (tf_loc
));
1398 VEC_quick_push (tree
, case_label_vec
, last_case
);
1401 x
= gimple_build_label (CASE_LABEL (last_case
));
1402 gimple_seq_add_stmt (&eh_seq
, x
);
1403 emit_resx (&eh_seq
, tf
->region
);
1406 x
= gimple_build_label (finally_label
);
1407 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1409 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1411 /* Redirect each incoming goto edge. */
1413 qe
= q
+ tf
->goto_queue_active
;
1414 j
= last_case_index
+ tf
->may_return
;
1415 /* Prepare the assignments to finally_tmp that are executed upon the
1416 entrance through a particular edge. */
1419 gimple_seq mod
= NULL
;
1421 unsigned int case_index
;
1425 x
= gimple_build_assign (finally_tmp
,
1426 build_int_cst (integer_type_node
,
1428 gimple_seq_add_stmt (&mod
, x
);
1429 do_return_redirection (q
, finally_label
, mod
);
1430 switch_id
= return_index
;
1434 x
= gimple_build_assign (finally_tmp
,
1435 build_int_cst (integer_type_node
, q
->index
));
1436 gimple_seq_add_stmt (&mod
, x
);
1437 do_goto_redirection (q
, finally_label
, mod
, tf
);
1438 switch_id
= q
->index
;
1441 case_index
= j
+ q
->index
;
1442 if (VEC_length (tree
, case_label_vec
) <= case_index
1443 || !VEC_index (tree
, case_label_vec
, case_index
))
1447 tmp
= build_int_cst (integer_type_node
, switch_id
);
1448 case_lab
= build_case_label (tmp
, NULL
,
1449 create_artificial_label (tf_loc
));
1450 /* We store the cont_stmt in the pointer map, so that we can recover
1451 it in the loop below. */
1453 cont_map
= pointer_map_create ();
1454 slot
= pointer_map_insert (cont_map
, case_lab
);
1455 *slot
= q
->cont_stmt
;
1456 VEC_quick_push (tree
, case_label_vec
, case_lab
);
1459 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1464 last_case
= VEC_index (tree
, case_label_vec
, j
);
1466 gcc_assert (last_case
);
1467 gcc_assert (cont_map
);
1469 slot
= pointer_map_contains (cont_map
, last_case
);
1471 cont_stmt
= *(gimple
*) slot
;
1473 x
= gimple_build_label (CASE_LABEL (last_case
));
1474 gimple_seq_add_stmt (&switch_body
, x
);
1475 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1476 maybe_record_in_goto_queue (state
, cont_stmt
);
1479 pointer_map_destroy (cont_map
);
1481 replace_goto_queue (tf
);
1483 /* Make sure that the last case is the default label, as one is required.
1484 Then sort the labels, which is also required in GIMPLE. */
1485 CASE_LOW (last_case
) = NULL
;
1486 sort_case_labels (case_label_vec
);
1488 /* Build the switch statement, setting last_case to be the default
1490 switch_stmt
= gimple_build_switch_vec (finally_tmp
, last_case
,
1492 gimple_set_location (switch_stmt
, finally_loc
);
1494 /* Need to link SWITCH_STMT after running replace_goto_queue
1495 due to not wanting to process the same goto stmts twice. */
1496 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1497 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1500 /* Decide whether or not we are going to duplicate the finally block.
1501 There are several considerations.
1503 First, if this is Java, then the finally block contains code
1504 written by the user. It has line numbers associated with it,
1505 so duplicating the block means it's difficult to set a breakpoint.
1506 Since controlling code generation via -g is verboten, we simply
1507 never duplicate code without optimization.
1509 Second, we'd like to prevent egregious code growth. One way to
1510 do this is to estimate the size of the finally block, multiply
1511 that by the number of copies we'd need to make, and compare against
1512 the estimate of the size of the switch machinery we'd have to add. */
1515 decide_copy_try_finally (int ndests
, bool may_throw
, gimple_seq finally
)
1517 int f_estimate
, sw_estimate
;
1520 /* If there's an EH_ELSE involved, the exception path is separate
1521 and really doesn't come into play for this computation. */
1522 eh_else
= get_eh_else (finally
);
1525 ndests
-= may_throw
;
1526 finally
= gimple_eh_else_n_body (eh_else
);
1531 gimple_stmt_iterator gsi
;
1536 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1538 gimple stmt
= gsi_stmt (gsi
);
1539 if (!is_gimple_debug (stmt
) && !gimple_clobber_p (stmt
))
1545 /* Finally estimate N times, plus N gotos. */
1546 f_estimate
= count_insns_seq (finally
, &eni_size_weights
);
1547 f_estimate
= (f_estimate
+ 1) * ndests
;
1549 /* Switch statement (cost 10), N variable assignments, N gotos. */
1550 sw_estimate
= 10 + 2 * ndests
;
1552 /* Optimize for size clearly wants our best guess. */
1553 if (optimize_function_for_size_p (cfun
))
1554 return f_estimate
< sw_estimate
;
1556 /* ??? These numbers are completely made up so far. */
1558 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1560 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1563 /* REG is the enclosing region for a possible cleanup region, or the region
1564 itself. Returns TRUE if such a region would be unreachable.
1566 Cleanup regions within a must-not-throw region aren't actually reachable
1567 even if there are throwing stmts within them, because the personality
1568 routine will call terminate before unwinding. */
1571 cleanup_is_dead_in (eh_region reg
)
1573 while (reg
&& reg
->type
== ERT_CLEANUP
)
1575 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1578 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1579 to a sequence of labels and blocks, plus the exception region trees
1580 that record all the magic. This is complicated by the need to
1581 arrange for the FINALLY block to be executed on all exits. */
1584 lower_try_finally (struct leh_state
*state
, gimple tp
)
1586 struct leh_tf_state this_tf
;
1587 struct leh_state this_state
;
1589 gimple_seq old_eh_seq
;
1591 /* Process the try block. */
1593 memset (&this_tf
, 0, sizeof (this_tf
));
1594 this_tf
.try_finally_expr
= tp
;
1596 this_tf
.outer
= state
;
1597 if (using_eh_for_cleanups_p
&& !cleanup_is_dead_in (state
->cur_region
))
1599 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1600 this_state
.cur_region
= this_tf
.region
;
1604 this_tf
.region
= NULL
;
1605 this_state
.cur_region
= state
->cur_region
;
1608 this_state
.ehp_region
= state
->ehp_region
;
1609 this_state
.tf
= &this_tf
;
1611 old_eh_seq
= eh_seq
;
1614 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1616 /* Determine if the try block is escaped through the bottom. */
1617 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1619 /* Determine if any exceptions are possible within the try block. */
1621 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1622 if (this_tf
.may_throw
)
1623 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1625 /* Determine how many edges (still) reach the finally block. Or rather,
1626 how many destinations are reached by the finally block. Use this to
1627 determine how we process the finally block itself. */
1629 ndests
= VEC_length (tree
, this_tf
.dest_array
);
1630 ndests
+= this_tf
.may_fallthru
;
1631 ndests
+= this_tf
.may_return
;
1632 ndests
+= this_tf
.may_throw
;
1634 /* If the FINALLY block is not reachable, dike it out. */
1637 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1638 gimple_try_set_cleanup (tp
, NULL
);
1640 /* If the finally block doesn't fall through, then any destination
1641 we might try to impose there isn't reached either. There may be
1642 some minor amount of cleanup and redirection still needed. */
1643 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1644 lower_try_finally_nofallthru (state
, &this_tf
);
1646 /* We can easily special-case redirection to a single destination. */
1647 else if (ndests
== 1)
1648 lower_try_finally_onedest (state
, &this_tf
);
1649 else if (decide_copy_try_finally (ndests
, this_tf
.may_throw
,
1650 gimple_try_cleanup (tp
)))
1651 lower_try_finally_copy (state
, &this_tf
);
1653 lower_try_finally_switch (state
, &this_tf
);
1655 /* If someone requested we add a label at the end of the transformed
1657 if (this_tf
.fallthru_label
)
1659 /* This must be reached only if ndests == 0. */
1660 gimple x
= gimple_build_label (this_tf
.fallthru_label
);
1661 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1664 VEC_free (tree
, heap
, this_tf
.dest_array
);
1665 free (this_tf
.goto_queue
);
1666 if (this_tf
.goto_queue_map
)
1667 pointer_map_destroy (this_tf
.goto_queue_map
);
1669 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1670 If there was no old eh_seq, then the append is trivially already done. */
1674 eh_seq
= old_eh_seq
;
1677 gimple_seq new_eh_seq
= eh_seq
;
1678 eh_seq
= old_eh_seq
;
1679 gimple_seq_add_seq(&eh_seq
, new_eh_seq
);
1683 return this_tf
.top_p_seq
;
1686 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1687 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1688 exception region trees that records all the magic. */
1691 lower_catch (struct leh_state
*state
, gimple tp
)
1693 eh_region try_region
= NULL
;
1694 struct leh_state this_state
= *state
;
1695 gimple_stmt_iterator gsi
;
1697 gimple_seq new_seq
, cleanup
;
1699 location_t try_catch_loc
= gimple_location (tp
);
1701 if (flag_exceptions
)
1703 try_region
= gen_eh_region_try (state
->cur_region
);
1704 this_state
.cur_region
= try_region
;
1707 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1709 if (!eh_region_may_contain_throw (try_region
))
1710 return gimple_try_eval (tp
);
1713 emit_eh_dispatch (&new_seq
, try_region
);
1714 emit_resx (&new_seq
, try_region
);
1716 this_state
.cur_region
= state
->cur_region
;
1717 this_state
.ehp_region
= try_region
;
1720 cleanup
= gimple_try_cleanup (tp
);
1721 for (gsi
= gsi_start (cleanup
);
1729 gcatch
= gsi_stmt (gsi
);
1730 c
= gen_eh_region_catch (try_region
, gimple_catch_types (gcatch
));
1732 handler
= gimple_catch_handler (gcatch
);
1733 lower_eh_constructs_1 (&this_state
, &handler
);
1735 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1736 x
= gimple_build_label (c
->label
);
1737 gimple_seq_add_stmt (&new_seq
, x
);
1739 gimple_seq_add_seq (&new_seq
, handler
);
1741 if (gimple_seq_may_fallthru (new_seq
))
1744 out_label
= create_artificial_label (try_catch_loc
);
1746 x
= gimple_build_goto (out_label
);
1747 gimple_seq_add_stmt (&new_seq
, x
);
1753 gimple_try_set_cleanup (tp
, new_seq
);
1755 return frob_into_branch_around (tp
, try_region
, out_label
);
1758 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1759 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1760 region trees that record all the magic. */
1763 lower_eh_filter (struct leh_state
*state
, gimple tp
)
1765 struct leh_state this_state
= *state
;
1766 eh_region this_region
= NULL
;
1770 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1772 if (flag_exceptions
)
1774 this_region
= gen_eh_region_allowed (state
->cur_region
,
1775 gimple_eh_filter_types (inner
));
1776 this_state
.cur_region
= this_region
;
1779 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1781 if (!eh_region_may_contain_throw (this_region
))
1782 return gimple_try_eval (tp
);
1785 this_state
.cur_region
= state
->cur_region
;
1786 this_state
.ehp_region
= this_region
;
1788 emit_eh_dispatch (&new_seq
, this_region
);
1789 emit_resx (&new_seq
, this_region
);
1791 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1792 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1793 gimple_seq_add_stmt (&new_seq
, x
);
1795 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure_ptr (inner
));
1796 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1798 gimple_try_set_cleanup (tp
, new_seq
);
1800 return frob_into_branch_around (tp
, this_region
, NULL
);
1803 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1804 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1805 plus the exception region trees that record all the magic. */
1808 lower_eh_must_not_throw (struct leh_state
*state
, gimple tp
)
1810 struct leh_state this_state
= *state
;
1812 if (flag_exceptions
)
1814 gimple inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1815 eh_region this_region
;
1817 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1818 this_region
->u
.must_not_throw
.failure_decl
1819 = gimple_eh_must_not_throw_fndecl (inner
);
1820 this_region
->u
.must_not_throw
.failure_loc
= gimple_location (tp
);
1822 /* In order to get mangling applied to this decl, we must mark it
1823 used now. Otherwise, pass_ipa_free_lang_data won't think it
1825 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1827 this_state
.cur_region
= this_region
;
1830 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1832 return gimple_try_eval (tp
);
1835 /* Implement a cleanup expression. This is similar to try-finally,
1836 except that we only execute the cleanup block for exception edges. */
1839 lower_cleanup (struct leh_state
*state
, gimple tp
)
1841 struct leh_state this_state
= *state
;
1842 eh_region this_region
= NULL
;
1843 struct leh_tf_state fake_tf
;
1845 bool cleanup_dead
= cleanup_is_dead_in (state
->cur_region
);
1847 if (flag_exceptions
&& !cleanup_dead
)
1849 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1850 this_state
.cur_region
= this_region
;
1853 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1855 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1856 return gimple_try_eval (tp
);
1858 /* Build enough of a try-finally state so that we can reuse
1859 honor_protect_cleanup_actions. */
1860 memset (&fake_tf
, 0, sizeof (fake_tf
));
1861 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1862 fake_tf
.outer
= state
;
1863 fake_tf
.region
= this_region
;
1864 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1865 fake_tf
.may_throw
= true;
1867 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1869 if (fake_tf
.may_throw
)
1871 /* In this case honor_protect_cleanup_actions had nothing to do,
1872 and we should process this normally. */
1873 lower_eh_constructs_1 (state
, gimple_try_cleanup_ptr (tp
));
1874 result
= frob_into_branch_around (tp
, this_region
,
1875 fake_tf
.fallthru_label
);
1879 /* In this case honor_protect_cleanup_actions did nearly all of
1880 the work. All we have left is to append the fallthru_label. */
1882 result
= gimple_try_eval (tp
);
1883 if (fake_tf
.fallthru_label
)
1885 gimple x
= gimple_build_label (fake_tf
.fallthru_label
);
1886 gimple_seq_add_stmt (&result
, x
);
1892 /* Main loop for lowering eh constructs. Also moves gsi to the next
1896 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1900 gimple stmt
= gsi_stmt (*gsi
);
1902 switch (gimple_code (stmt
))
1906 tree fndecl
= gimple_call_fndecl (stmt
);
1909 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1910 switch (DECL_FUNCTION_CODE (fndecl
))
1912 case BUILT_IN_EH_POINTER
:
1913 /* The front end may have generated a call to
1914 __builtin_eh_pointer (0) within a catch region. Replace
1915 this zero argument with the current catch region number. */
1916 if (state
->ehp_region
)
1918 tree nr
= build_int_cst (integer_type_node
,
1919 state
->ehp_region
->index
);
1920 gimple_call_set_arg (stmt
, 0, nr
);
1924 /* The user has dome something silly. Remove it. */
1925 rhs
= null_pointer_node
;
1930 case BUILT_IN_EH_FILTER
:
1931 /* ??? This should never appear, but since it's a builtin it
1932 is accessible to abuse by users. Just remove it and
1933 replace the use with the arbitrary value zero. */
1934 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
1936 lhs
= gimple_call_lhs (stmt
);
1937 x
= gimple_build_assign (lhs
, rhs
);
1938 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
1941 case BUILT_IN_EH_COPY_VALUES
:
1942 /* Likewise this should not appear. Remove it. */
1943 gsi_remove (gsi
, true);
1953 /* If the stmt can throw use a new temporary for the assignment
1954 to a LHS. This makes sure the old value of the LHS is
1955 available on the EH edge. Only do so for statements that
1956 potentially fall through (no noreturn calls e.g.), otherwise
1957 this new assignment might create fake fallthru regions. */
1958 if (stmt_could_throw_p (stmt
)
1959 && gimple_has_lhs (stmt
)
1960 && gimple_stmt_may_fallthru (stmt
)
1961 && !tree_could_throw_p (gimple_get_lhs (stmt
))
1962 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
1964 tree lhs
= gimple_get_lhs (stmt
);
1965 tree tmp
= create_tmp_var (TREE_TYPE (lhs
), NULL
);
1966 gimple s
= gimple_build_assign (lhs
, tmp
);
1967 gimple_set_location (s
, gimple_location (stmt
));
1968 gimple_set_block (s
, gimple_block (stmt
));
1969 gimple_set_lhs (stmt
, tmp
);
1970 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
1971 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
1972 DECL_GIMPLE_REG_P (tmp
) = 1;
1973 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
1975 /* Look for things that can throw exceptions, and record them. */
1976 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
1978 record_stmt_eh_region (state
->cur_region
, stmt
);
1979 note_eh_region_may_contain_throw (state
->cur_region
);
1986 maybe_record_in_goto_queue (state
, stmt
);
1990 verify_norecord_switch_expr (state
, stmt
);
1994 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
1995 replace
= lower_try_finally (state
, stmt
);
1998 x
= gimple_seq_first_stmt (gimple_try_cleanup (stmt
));
2001 replace
= gimple_try_eval (stmt
);
2002 lower_eh_constructs_1 (state
, &replace
);
2005 switch (gimple_code (x
))
2008 replace
= lower_catch (state
, stmt
);
2010 case GIMPLE_EH_FILTER
:
2011 replace
= lower_eh_filter (state
, stmt
);
2013 case GIMPLE_EH_MUST_NOT_THROW
:
2014 replace
= lower_eh_must_not_throw (state
, stmt
);
2016 case GIMPLE_EH_ELSE
:
2017 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2020 replace
= lower_cleanup (state
, stmt
);
2025 /* Remove the old stmt and insert the transformed sequence
2027 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2028 gsi_remove (gsi
, true);
2030 /* Return since we don't want gsi_next () */
2033 case GIMPLE_EH_ELSE
:
2034 /* We should be eliminating this in lower_try_finally et al. */
2038 /* A type, a decl, or some kind of statement that we're not
2039 interested in. Don't walk them. */
2046 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2049 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*pseq
)
2051 gimple_stmt_iterator gsi
;
2052 for (gsi
= gsi_start (*pseq
); !gsi_end_p (gsi
);)
2053 lower_eh_constructs_2 (state
, &gsi
);
2057 lower_eh_constructs (void)
2059 struct leh_state null_state
;
2062 bodyp
= gimple_body (current_function_decl
);
2066 finally_tree
= htab_create (31, struct_ptr_hash
, struct_ptr_eq
, free
);
2067 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2068 memset (&null_state
, 0, sizeof (null_state
));
2070 collect_finally_tree_1 (bodyp
, NULL
);
2071 lower_eh_constructs_1 (&null_state
, &bodyp
);
2072 gimple_set_body (current_function_decl
, bodyp
);
2074 /* We assume there's a return statement, or something, at the end of
2075 the function, and thus ploping the EH sequence afterward won't
2077 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2078 gimple_seq_add_seq (&bodyp
, eh_seq
);
2080 /* We assume that since BODYP already existed, adding EH_SEQ to it
2081 didn't change its value, and we don't have to re-set the function. */
2082 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2084 htab_delete (finally_tree
);
2085 BITMAP_FREE (eh_region_may_contain_throw_map
);
2088 /* If this function needs a language specific EH personality routine
2089 and the frontend didn't already set one do so now. */
2090 if (function_needs_eh_personality (cfun
) == eh_personality_lang
2091 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2092 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2093 = lang_hooks
.eh_personality ();
2098 struct gimple_opt_pass pass_lower_eh
=
2104 lower_eh_constructs
, /* execute */
2107 0, /* static_pass_number */
2108 TV_TREE_EH
, /* tv_id */
2109 PROP_gimple_lcf
, /* properties_required */
2110 PROP_gimple_leh
, /* properties_provided */
2111 0, /* properties_destroyed */
2112 0, /* todo_flags_start */
2113 0 /* todo_flags_finish */
2117 /* Create the multiple edges from an EH_DISPATCH statement to all of
2118 the possible handlers for its EH region. Return true if there's
2119 no fallthru edge; false if there is. */
2122 make_eh_dispatch_edges (gimple stmt
)
2126 basic_block src
, dst
;
2128 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2129 src
= gimple_bb (stmt
);
2134 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2136 dst
= label_to_block (c
->label
);
2137 make_edge (src
, dst
, 0);
2139 /* A catch-all handler doesn't have a fallthru. */
2140 if (c
->type_list
== NULL
)
2145 case ERT_ALLOWED_EXCEPTIONS
:
2146 dst
= label_to_block (r
->u
.allowed
.label
);
2147 make_edge (src
, dst
, 0);
2157 /* Create the single EH edge from STMT to its nearest landing pad,
2158 if there is such a landing pad within the current function. */
2161 make_eh_edges (gimple stmt
)
2163 basic_block src
, dst
;
2167 lp_nr
= lookup_stmt_eh_lp (stmt
);
2171 lp
= get_eh_landing_pad_from_number (lp_nr
);
2172 gcc_assert (lp
!= NULL
);
2174 src
= gimple_bb (stmt
);
2175 dst
= label_to_block (lp
->post_landing_pad
);
2176 make_edge (src
, dst
, EDGE_EH
);
2179 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2180 do not actually perform the final edge redirection.
2182 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2183 we intend to change the destination EH region as well; this means
2184 EH_LANDING_PAD_NR must already be set on the destination block label.
2185 If false, we're being called from generic cfg manipulation code and we
2186 should preserve our place within the region tree. */
2189 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2191 eh_landing_pad old_lp
, new_lp
;
2194 int old_lp_nr
, new_lp_nr
;
2195 tree old_label
, new_label
;
2199 old_bb
= edge_in
->dest
;
2200 old_label
= gimple_block_label (old_bb
);
2201 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2202 gcc_assert (old_lp_nr
> 0);
2203 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2205 throw_stmt
= last_stmt (edge_in
->src
);
2206 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2208 new_label
= gimple_block_label (new_bb
);
2210 /* Look for an existing region that might be using NEW_BB already. */
2211 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2214 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2215 gcc_assert (new_lp
);
2217 /* Unless CHANGE_REGION is true, the new and old landing pad
2218 had better be associated with the same EH region. */
2219 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2224 gcc_assert (!change_region
);
2227 /* Notice when we redirect the last EH edge away from OLD_BB. */
2228 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2229 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2234 /* NEW_LP already exists. If there are still edges into OLD_LP,
2235 there's nothing to do with the EH tree. If there are no more
2236 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2237 If CHANGE_REGION is true, then our caller is expecting to remove
2239 if (e
== NULL
&& !change_region
)
2240 remove_eh_landing_pad (old_lp
);
2244 /* No correct landing pad exists. If there are no more edges
2245 into OLD_LP, then we can simply re-use the existing landing pad.
2246 Otherwise, we have to create a new landing pad. */
2249 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2253 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2254 new_lp
->post_landing_pad
= new_label
;
2255 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2258 /* Maybe move the throwing statement to the new region. */
2259 if (old_lp
!= new_lp
)
2261 remove_stmt_from_eh_lp (throw_stmt
);
2262 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2266 /* Redirect EH edge E to NEW_BB. */
2269 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2271 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2272 return ssa_redirect_edge (edge_in
, new_bb
);
2275 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2276 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2277 The actual edge update will happen in the caller. */
2280 redirect_eh_dispatch_edge (gimple stmt
, edge e
, basic_block new_bb
)
2282 tree new_lab
= gimple_block_label (new_bb
);
2283 bool any_changed
= false;
2288 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2292 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2294 old_bb
= label_to_block (c
->label
);
2295 if (old_bb
== e
->dest
)
2303 case ERT_ALLOWED_EXCEPTIONS
:
2304 old_bb
= label_to_block (r
->u
.allowed
.label
);
2305 gcc_assert (old_bb
== e
->dest
);
2306 r
->u
.allowed
.label
= new_lab
;
2314 gcc_assert (any_changed
);
2317 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2320 operation_could_trap_helper_p (enum tree_code op
,
2331 case TRUNC_DIV_EXPR
:
2333 case FLOOR_DIV_EXPR
:
2334 case ROUND_DIV_EXPR
:
2335 case EXACT_DIV_EXPR
:
2337 case FLOOR_MOD_EXPR
:
2338 case ROUND_MOD_EXPR
:
2339 case TRUNC_MOD_EXPR
:
2341 if (honor_snans
|| honor_trapv
)
2344 return flag_trapping_math
;
2345 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2354 /* Some floating point comparisons may trap. */
2359 case UNORDERED_EXPR
:
2369 case FIX_TRUNC_EXPR
:
2370 /* Conversion of floating point might trap. */
2376 /* These operations don't trap with floating point. */
2384 /* Any floating arithmetic may trap. */
2385 if (fp_operation
&& flag_trapping_math
)
2393 /* Constructing an object cannot trap. */
2397 /* Any floating arithmetic may trap. */
2398 if (fp_operation
&& flag_trapping_math
)
2406 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2407 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2408 type operands that may trap. If OP is a division operator, DIVISOR contains
2409 the value of the divisor. */
2412 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2415 bool honor_nans
= (fp_operation
&& flag_trapping_math
2416 && !flag_finite_math_only
);
2417 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2420 if (TREE_CODE_CLASS (op
) != tcc_comparison
2421 && TREE_CODE_CLASS (op
) != tcc_unary
2422 && TREE_CODE_CLASS (op
) != tcc_binary
)
2425 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2426 honor_nans
, honor_snans
, divisor
,
2430 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2431 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2432 This routine expects only GIMPLE lhs or rhs input. */
2435 tree_could_trap_p (tree expr
)
2437 enum tree_code code
;
2438 bool fp_operation
= false;
2439 bool honor_trapv
= false;
2440 tree t
, base
, div
= NULL_TREE
;
2445 code
= TREE_CODE (expr
);
2446 t
= TREE_TYPE (expr
);
2450 if (COMPARISON_CLASS_P (expr
))
2451 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2453 fp_operation
= FLOAT_TYPE_P (t
);
2454 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2457 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2458 div
= TREE_OPERAND (expr
, 1);
2459 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2465 case TARGET_MEM_REF
:
2466 if (TREE_CODE (TMR_BASE (expr
)) == ADDR_EXPR
2467 && !TMR_INDEX (expr
) && !TMR_INDEX2 (expr
))
2469 return !TREE_THIS_NOTRAP (expr
);
2475 case VIEW_CONVERT_EXPR
:
2476 case WITH_SIZE_EXPR
:
2477 expr
= TREE_OPERAND (expr
, 0);
2478 code
= TREE_CODE (expr
);
2481 case ARRAY_RANGE_REF
:
2482 base
= TREE_OPERAND (expr
, 0);
2483 if (tree_could_trap_p (base
))
2485 if (TREE_THIS_NOTRAP (expr
))
2487 return !range_in_array_bounds_p (expr
);
2490 base
= TREE_OPERAND (expr
, 0);
2491 if (tree_could_trap_p (base
))
2493 if (TREE_THIS_NOTRAP (expr
))
2495 return !in_array_bounds_p (expr
);
2498 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2502 return !TREE_THIS_NOTRAP (expr
);
2505 return TREE_THIS_VOLATILE (expr
);
2508 t
= get_callee_fndecl (expr
);
2509 /* Assume that calls to weak functions may trap. */
2510 if (!t
|| !DECL_P (t
))
2513 return tree_could_trap_p (t
);
2517 /* Assume that accesses to weak functions may trap, unless we know
2518 they are certainly defined in current TU or in some other
2520 if (DECL_WEAK (expr
))
2522 struct cgraph_node
*node
;
2523 if (!DECL_EXTERNAL (expr
))
2525 node
= cgraph_function_node (cgraph_get_node (expr
), NULL
);
2526 if (node
&& node
->symbol
.in_other_partition
)
2533 /* Assume that accesses to weak vars may trap, unless we know
2534 they are certainly defined in current TU or in some other
2536 if (DECL_WEAK (expr
))
2538 struct varpool_node
*node
;
2539 if (!DECL_EXTERNAL (expr
))
2541 node
= varpool_variable_node (varpool_get_node (expr
), NULL
);
2542 if (node
&& node
->symbol
.in_other_partition
)
2554 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2555 an assignment or a conditional) may throw. */
2558 stmt_could_throw_1_p (gimple stmt
)
2560 enum tree_code code
= gimple_expr_code (stmt
);
2561 bool honor_nans
= false;
2562 bool honor_snans
= false;
2563 bool fp_operation
= false;
2564 bool honor_trapv
= false;
2569 if (TREE_CODE_CLASS (code
) == tcc_comparison
2570 || TREE_CODE_CLASS (code
) == tcc_unary
2571 || TREE_CODE_CLASS (code
) == tcc_binary
)
2573 if (is_gimple_assign (stmt
)
2574 && TREE_CODE_CLASS (code
) == tcc_comparison
)
2575 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2576 else if (gimple_code (stmt
) == GIMPLE_COND
)
2577 t
= TREE_TYPE (gimple_cond_lhs (stmt
));
2579 t
= gimple_expr_type (stmt
);
2580 fp_operation
= FLOAT_TYPE_P (t
);
2583 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2584 honor_snans
= flag_signaling_nans
!= 0;
2586 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2590 /* Check if the main expression may trap. */
2591 t
= is_gimple_assign (stmt
) ? gimple_assign_rhs2 (stmt
) : NULL
;
2592 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2593 honor_nans
, honor_snans
, t
,
2598 /* If the expression does not trap, see if any of the individual operands may
2600 for (i
= 0; i
< gimple_num_ops (stmt
); i
++)
2601 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2608 /* Return true if statement STMT could throw an exception. */
2611 stmt_could_throw_p (gimple stmt
)
2613 if (!flag_exceptions
)
2616 /* The only statements that can throw an exception are assignments,
2617 conditionals, calls, resx, and asms. */
2618 switch (gimple_code (stmt
))
2624 return !gimple_call_nothrow_p (stmt
);
2628 if (!cfun
->can_throw_non_call_exceptions
)
2630 return stmt_could_throw_1_p (stmt
);
2633 if (!cfun
->can_throw_non_call_exceptions
)
2635 return gimple_asm_volatile_p (stmt
);
2643 /* Return true if expression T could throw an exception. */
2646 tree_could_throw_p (tree t
)
2648 if (!flag_exceptions
)
2650 if (TREE_CODE (t
) == MODIFY_EXPR
)
2652 if (cfun
->can_throw_non_call_exceptions
2653 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2655 t
= TREE_OPERAND (t
, 1);
2658 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2659 t
= TREE_OPERAND (t
, 0);
2660 if (TREE_CODE (t
) == CALL_EXPR
)
2661 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2662 if (cfun
->can_throw_non_call_exceptions
)
2663 return tree_could_trap_p (t
);
2667 /* Return true if STMT can throw an exception that is not caught within
2668 the current function (CFUN). */
2671 stmt_can_throw_external (gimple stmt
)
2675 if (!stmt_could_throw_p (stmt
))
2678 lp_nr
= lookup_stmt_eh_lp (stmt
);
2682 /* Return true if STMT can throw an exception that is caught within
2683 the current function (CFUN). */
2686 stmt_can_throw_internal (gimple stmt
)
2690 if (!stmt_could_throw_p (stmt
))
2693 lp_nr
= lookup_stmt_eh_lp (stmt
);
2697 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2698 remove any entry it might have from the EH table. Return true if
2699 any change was made. */
2702 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple stmt
)
2704 if (stmt_could_throw_p (stmt
))
2706 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2709 /* Likewise, but always use the current function. */
2712 maybe_clean_eh_stmt (gimple stmt
)
2714 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2717 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2718 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2719 in the table if it should be in there. Return TRUE if a replacement was
2720 done that my require an EH edge purge. */
2723 maybe_clean_or_replace_eh_stmt (gimple old_stmt
, gimple new_stmt
)
2725 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2729 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2731 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2734 remove_stmt_from_eh_lp (old_stmt
);
2735 if (new_stmt_could_throw
)
2737 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2747 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
2748 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2749 operand is the return value of duplicate_eh_regions. */
2752 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple new_stmt
,
2753 struct function
*old_fun
, gimple old_stmt
,
2754 struct pointer_map_t
*map
, int default_lp_nr
)
2756 int old_lp_nr
, new_lp_nr
;
2759 if (!stmt_could_throw_p (new_stmt
))
2762 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2765 if (default_lp_nr
== 0)
2767 new_lp_nr
= default_lp_nr
;
2769 else if (old_lp_nr
> 0)
2771 eh_landing_pad old_lp
, new_lp
;
2773 old_lp
= VEC_index (eh_landing_pad
, old_fun
->eh
->lp_array
, old_lp_nr
);
2774 slot
= pointer_map_contains (map
, old_lp
);
2775 new_lp
= (eh_landing_pad
) *slot
;
2776 new_lp_nr
= new_lp
->index
;
2780 eh_region old_r
, new_r
;
2782 old_r
= VEC_index (eh_region
, old_fun
->eh
->region_array
, -old_lp_nr
);
2783 slot
= pointer_map_contains (map
, old_r
);
2784 new_r
= (eh_region
) *slot
;
2785 new_lp_nr
= -new_r
->index
;
2788 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2792 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2793 and thus no remapping is required. */
2796 maybe_duplicate_eh_stmt (gimple new_stmt
, gimple old_stmt
)
2800 if (!stmt_could_throw_p (new_stmt
))
2803 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2807 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2811 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2812 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2813 this only handles handlers consisting of a single call, as that's the
2814 important case for C++: a destructor call for a particular object showing
2815 up in multiple handlers. */
2818 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2820 gimple_stmt_iterator gsi
;
2824 gsi
= gsi_start (oneh
);
2825 if (!gsi_one_before_end_p (gsi
))
2827 ones
= gsi_stmt (gsi
);
2829 gsi
= gsi_start (twoh
);
2830 if (!gsi_one_before_end_p (gsi
))
2832 twos
= gsi_stmt (gsi
);
2834 if (!is_gimple_call (ones
)
2835 || !is_gimple_call (twos
)
2836 || gimple_call_lhs (ones
)
2837 || gimple_call_lhs (twos
)
2838 || gimple_call_chain (ones
)
2839 || gimple_call_chain (twos
)
2840 || !gimple_call_same_target_p (ones
, twos
)
2841 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
2844 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
2845 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
2846 gimple_call_arg (twos
, ai
), 0))
2853 try { A() } finally { try { ~B() } catch { ~A() } }
2854 try { ... } finally { ~A() }
2856 try { A() } catch { ~B() }
2857 try { ~B() ... } finally { ~A() }
2859 This occurs frequently in C++, where A is a local variable and B is a
2860 temporary used in the initializer for A. */
2863 optimize_double_finally (gimple one
, gimple two
)
2866 gimple_stmt_iterator gsi
;
2869 cleanup
= gimple_try_cleanup (one
);
2870 gsi
= gsi_start (cleanup
);
2871 if (!gsi_one_before_end_p (gsi
))
2874 oneh
= gsi_stmt (gsi
);
2875 if (gimple_code (oneh
) != GIMPLE_TRY
2876 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
2879 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
2881 gimple_seq seq
= gimple_try_eval (oneh
);
2883 gimple_try_set_cleanup (one
, seq
);
2884 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
2885 seq
= copy_gimple_seq_and_replace_locals (seq
);
2886 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
2887 gimple_try_set_eval (two
, seq
);
2891 /* Perform EH refactoring optimizations that are simpler to do when code
2892 flow has been lowered but EH structures haven't. */
2895 refactor_eh_r (gimple_seq seq
)
2897 gimple_stmt_iterator gsi
;
2902 gsi
= gsi_start (seq
);
2906 if (gsi_end_p (gsi
))
2909 two
= gsi_stmt (gsi
);
2912 && gimple_code (one
) == GIMPLE_TRY
2913 && gimple_code (two
) == GIMPLE_TRY
2914 && gimple_try_kind (one
) == GIMPLE_TRY_FINALLY
2915 && gimple_try_kind (two
) == GIMPLE_TRY_FINALLY
)
2916 optimize_double_finally (one
, two
);
2918 switch (gimple_code (one
))
2921 refactor_eh_r (gimple_try_eval (one
));
2922 refactor_eh_r (gimple_try_cleanup (one
));
2925 refactor_eh_r (gimple_catch_handler (one
));
2927 case GIMPLE_EH_FILTER
:
2928 refactor_eh_r (gimple_eh_filter_failure (one
));
2930 case GIMPLE_EH_ELSE
:
2931 refactor_eh_r (gimple_eh_else_n_body (one
));
2932 refactor_eh_r (gimple_eh_else_e_body (one
));
2947 refactor_eh_r (gimple_body (current_function_decl
));
2952 gate_refactor_eh (void)
2954 return flag_exceptions
!= 0;
2957 struct gimple_opt_pass pass_refactor_eh
=
2962 gate_refactor_eh
, /* gate */
2963 refactor_eh
, /* execute */
2966 0, /* static_pass_number */
2967 TV_TREE_EH
, /* tv_id */
2968 PROP_gimple_lcf
, /* properties_required */
2969 0, /* properties_provided */
2970 0, /* properties_destroyed */
2971 0, /* todo_flags_start */
2972 0 /* todo_flags_finish */
2976 /* At the end of gimple optimization, we can lower RESX. */
2979 lower_resx (basic_block bb
, gimple stmt
, struct pointer_map_t
*mnt_map
)
2982 eh_region src_r
, dst_r
;
2983 gimple_stmt_iterator gsi
;
2988 lp_nr
= lookup_stmt_eh_lp (stmt
);
2990 dst_r
= get_eh_region_from_lp_number (lp_nr
);
2994 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
2995 gsi
= gsi_last_bb (bb
);
2999 /* We can wind up with no source region when pass_cleanup_eh shows
3000 that there are no entries into an eh region and deletes it, but
3001 then the block that contains the resx isn't removed. This can
3002 happen without optimization when the switch statement created by
3003 lower_try_finally_switch isn't simplified to remove the eh case.
3005 Resolve this by expanding the resx node to an abort. */
3007 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3008 x
= gimple_build_call (fn
, 0);
3009 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3011 while (EDGE_COUNT (bb
->succs
) > 0)
3012 remove_edge (EDGE_SUCC (bb
, 0));
3016 /* When we have a destination region, we resolve this by copying
3017 the excptr and filter values into place, and changing the edge
3018 to immediately after the landing pad. */
3027 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3028 the failure decl into a new block, if needed. */
3029 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3031 slot
= pointer_map_contains (mnt_map
, dst_r
);
3034 gimple_stmt_iterator gsi2
;
3036 new_bb
= create_empty_bb (bb
);
3038 add_bb_to_loop (new_bb
, bb
->loop_father
);
3039 lab
= gimple_block_label (new_bb
);
3040 gsi2
= gsi_start_bb (new_bb
);
3042 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3043 x
= gimple_build_call (fn
, 0);
3044 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3045 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3047 slot
= pointer_map_insert (mnt_map
, dst_r
);
3053 new_bb
= label_to_block (lab
);
3056 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3057 e
= make_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3058 e
->count
= bb
->count
;
3059 e
->probability
= REG_BR_PROB_BASE
;
3064 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3066 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3067 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3068 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3069 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3071 /* Update the flags for the outgoing edge. */
3072 e
= single_succ_edge (bb
);
3073 gcc_assert (e
->flags
& EDGE_EH
);
3074 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3076 /* If there are no more EH users of the landing pad, delete it. */
3077 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3078 if (e
->flags
& EDGE_EH
)
3082 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3083 remove_eh_landing_pad (lp
);
3093 /* When we don't have a destination region, this exception escapes
3094 up the call chain. We resolve this by generating a call to the
3095 _Unwind_Resume library function. */
3097 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3098 with no arguments for C++ and Java. Check for that. */
3099 if (src_r
->use_cxa_end_cleanup
)
3101 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3102 x
= gimple_build_call (fn
, 0);
3103 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3107 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3108 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3109 x
= gimple_build_call (fn
, 1, src_nr
);
3110 var
= create_tmp_var (ptr_type_node
, NULL
);
3111 var
= make_ssa_name (var
, x
);
3112 gimple_call_set_lhs (x
, var
);
3113 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3115 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3116 x
= gimple_build_call (fn
, 1, var
);
3117 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3120 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3123 gsi_remove (&gsi
, true);
3129 execute_lower_resx (void)
3132 struct pointer_map_t
*mnt_map
;
3133 bool dominance_invalidated
= false;
3134 bool any_rewritten
= false;
3136 mnt_map
= pointer_map_create ();
3140 gimple last
= last_stmt (bb
);
3141 if (last
&& is_gimple_resx (last
))
3143 dominance_invalidated
|= lower_resx (bb
, last
, mnt_map
);
3144 any_rewritten
= true;
3148 pointer_map_destroy (mnt_map
);
3150 if (dominance_invalidated
)
3152 free_dominance_info (CDI_DOMINATORS
);
3153 free_dominance_info (CDI_POST_DOMINATORS
);
3156 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3160 gate_lower_resx (void)
3162 return flag_exceptions
!= 0;
3165 struct gimple_opt_pass pass_lower_resx
=
3170 gate_lower_resx
, /* gate */
3171 execute_lower_resx
, /* execute */
3174 0, /* static_pass_number */
3175 TV_TREE_EH
, /* tv_id */
3176 PROP_gimple_lcf
, /* properties_required */
3177 0, /* properties_provided */
3178 0, /* properties_destroyed */
3179 0, /* todo_flags_start */
3180 TODO_verify_flow
/* todo_flags_finish */
3184 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3188 optimize_clobbers (basic_block bb
)
3190 gimple_stmt_iterator gsi
= gsi_last_bb (bb
);
3191 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3193 gimple stmt
= gsi_stmt (gsi
);
3194 if (is_gimple_debug (stmt
))
3196 if (!gimple_clobber_p (stmt
)
3197 || TREE_CODE (gimple_assign_lhs (stmt
)) == SSA_NAME
)
3199 unlink_stmt_vdef (stmt
);
3200 gsi_remove (&gsi
, true);
3201 release_defs (stmt
);
3205 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3206 internal throw to successor BB. */
3209 sink_clobbers (basic_block bb
)
3213 gimple_stmt_iterator gsi
, dgsi
;
3215 bool any_clobbers
= false;
3217 /* Only optimize if BB has a single EH successor and
3218 all predecessor edges are EH too. */
3219 if (!single_succ_p (bb
)
3220 || (single_succ_edge (bb
)->flags
& EDGE_EH
) == 0)
3223 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3225 if ((e
->flags
& EDGE_EH
) == 0)
3229 /* And BB contains only CLOBBER stmts before the final
3231 gsi
= gsi_last_bb (bb
);
3232 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3234 gimple stmt
= gsi_stmt (gsi
);
3235 if (is_gimple_debug (stmt
))
3237 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3239 if (!gimple_clobber_p (stmt
)
3240 || TREE_CODE (gimple_assign_lhs (stmt
)) == SSA_NAME
)
3242 any_clobbers
= true;
3247 succbb
= single_succ (bb
);
3248 dgsi
= gsi_after_labels (succbb
);
3249 gsi
= gsi_last_bb (bb
);
3250 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3252 gimple stmt
= gsi_stmt (gsi
);
3254 if (is_gimple_debug (stmt
))
3256 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3258 unlink_stmt_vdef (stmt
);
3259 gsi_remove (&gsi
, false);
3260 vdef
= gimple_vdef (stmt
);
3261 if (vdef
&& TREE_CODE (vdef
) == SSA_NAME
)
3263 release_ssa_name (vdef
);
3264 vdef
= SSA_NAME_VAR (vdef
);
3265 mark_sym_for_renaming (vdef
);
3266 gimple_set_vdef (stmt
, vdef
);
3267 gimple_set_vuse (stmt
, vdef
);
3269 gsi_insert_before (&dgsi
, stmt
, GSI_SAME_STMT
);
3272 return TODO_update_ssa_only_virtuals
;
3275 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3276 we have found some duplicate labels and removed some edges. */
3279 lower_eh_dispatch (basic_block src
, gimple stmt
)
3281 gimple_stmt_iterator gsi
;
3286 bool redirected
= false;
3288 region_nr
= gimple_eh_dispatch_region (stmt
);
3289 r
= get_eh_region_from_number (region_nr
);
3291 gsi
= gsi_last_bb (src
);
3297 VEC (tree
, heap
) *labels
= NULL
;
3298 tree default_label
= NULL
;
3302 struct pointer_set_t
*seen_values
= pointer_set_create ();
3304 /* Collect the labels for a switch. Zero the post_landing_pad
3305 field becase we'll no longer have anything keeping these labels
3306 in existence and the optimizer will be free to merge these
3308 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3310 tree tp_node
, flt_node
, lab
= c
->label
;
3311 bool have_label
= false;
3314 tp_node
= c
->type_list
;
3315 flt_node
= c
->filter_list
;
3317 if (tp_node
== NULL
)
3319 default_label
= lab
;
3324 /* Filter out duplicate labels that arise when this handler
3325 is shadowed by an earlier one. When no labels are
3326 attached to the handler anymore, we remove
3327 the corresponding edge and then we delete unreachable
3328 blocks at the end of this pass. */
3329 if (! pointer_set_contains (seen_values
, TREE_VALUE (flt_node
)))
3331 tree t
= build_case_label (TREE_VALUE (flt_node
),
3333 VEC_safe_push (tree
, heap
, labels
, t
);
3334 pointer_set_insert (seen_values
, TREE_VALUE (flt_node
));
3338 tp_node
= TREE_CHAIN (tp_node
);
3339 flt_node
= TREE_CHAIN (flt_node
);
3344 remove_edge (find_edge (src
, label_to_block (lab
)));
3349 /* Clean up the edge flags. */
3350 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3352 if (e
->flags
& EDGE_FALLTHRU
)
3354 /* If there was no catch-all, use the fallthru edge. */
3355 if (default_label
== NULL
)
3356 default_label
= gimple_block_label (e
->dest
);
3357 e
->flags
&= ~EDGE_FALLTHRU
;
3360 gcc_assert (default_label
!= NULL
);
3362 /* Don't generate a switch if there's only a default case.
3363 This is common in the form of try { A; } catch (...) { B; }. */
3366 e
= single_succ_edge (src
);
3367 e
->flags
|= EDGE_FALLTHRU
;
3371 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3372 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3374 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3375 filter
= make_ssa_name (filter
, x
);
3376 gimple_call_set_lhs (x
, filter
);
3377 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3379 /* Turn the default label into a default case. */
3380 default_label
= build_case_label (NULL
, NULL
, default_label
);
3381 sort_case_labels (labels
);
3383 x
= gimple_build_switch_vec (filter
, default_label
, labels
);
3384 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3386 VEC_free (tree
, heap
, labels
);
3388 pointer_set_destroy (seen_values
);
3392 case ERT_ALLOWED_EXCEPTIONS
:
3394 edge b_e
= BRANCH_EDGE (src
);
3395 edge f_e
= FALLTHRU_EDGE (src
);
3397 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3398 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3400 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3401 filter
= make_ssa_name (filter
, x
);
3402 gimple_call_set_lhs (x
, filter
);
3403 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3405 r
->u
.allowed
.label
= NULL
;
3406 x
= gimple_build_cond (EQ_EXPR
, filter
,
3407 build_int_cst (TREE_TYPE (filter
),
3408 r
->u
.allowed
.filter
),
3409 NULL_TREE
, NULL_TREE
);
3410 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3412 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3413 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3421 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3422 gsi_remove (&gsi
, true);
3427 execute_lower_eh_dispatch (void)
3431 bool redirected
= false;
3433 assign_filter_values ();
3437 gimple last
= last_stmt (bb
);
3440 if (gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3442 redirected
|= lower_eh_dispatch (bb
, last
);
3443 flags
|= TODO_update_ssa_only_virtuals
;
3445 else if (gimple_code (last
) == GIMPLE_RESX
)
3447 if (stmt_can_throw_external (last
))
3448 optimize_clobbers (bb
);
3450 flags
|= sink_clobbers (bb
);
3455 delete_unreachable_blocks ();
3460 gate_lower_eh_dispatch (void)
3462 return cfun
->eh
->region_tree
!= NULL
;
3465 struct gimple_opt_pass pass_lower_eh_dispatch
=
3469 "ehdisp", /* name */
3470 gate_lower_eh_dispatch
, /* gate */
3471 execute_lower_eh_dispatch
, /* execute */
3474 0, /* static_pass_number */
3475 TV_TREE_EH
, /* tv_id */
3476 PROP_gimple_lcf
, /* properties_required */
3477 0, /* properties_provided */
3478 0, /* properties_destroyed */
3479 0, /* todo_flags_start */
3480 TODO_verify_flow
/* todo_flags_finish */
3484 /* Walk statements, see what regions are really referenced and remove
3485 those that are unused. */
3488 remove_unreachable_handlers (void)
3490 sbitmap r_reachable
, lp_reachable
;
3496 r_reachable
= sbitmap_alloc (VEC_length (eh_region
, cfun
->eh
->region_array
));
3498 = sbitmap_alloc (VEC_length (eh_landing_pad
, cfun
->eh
->lp_array
));
3499 sbitmap_zero (r_reachable
);
3500 sbitmap_zero (lp_reachable
);
3504 gimple_stmt_iterator gsi
;
3506 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3508 gimple stmt
= gsi_stmt (gsi
);
3509 lp_nr
= lookup_stmt_eh_lp (stmt
);
3511 /* Negative LP numbers are MUST_NOT_THROW regions which
3512 are not considered BB enders. */
3514 SET_BIT (r_reachable
, -lp_nr
);
3516 /* Positive LP numbers are real landing pads, are are BB enders. */
3519 gcc_assert (gsi_one_before_end_p (gsi
));
3520 region
= get_eh_region_from_lp_number (lp_nr
);
3521 SET_BIT (r_reachable
, region
->index
);
3522 SET_BIT (lp_reachable
, lp_nr
);
3525 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3526 switch (gimple_code (stmt
))
3529 SET_BIT (r_reachable
, gimple_resx_region (stmt
));
3531 case GIMPLE_EH_DISPATCH
:
3532 SET_BIT (r_reachable
, gimple_eh_dispatch_region (stmt
));
3542 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3543 dump_eh_tree (dump_file
, cfun
);
3544 fprintf (dump_file
, "Reachable regions: ");
3545 dump_sbitmap_file (dump_file
, r_reachable
);
3546 fprintf (dump_file
, "Reachable landing pads: ");
3547 dump_sbitmap_file (dump_file
, lp_reachable
);
3551 VEC_iterate (eh_region
, cfun
->eh
->region_array
, r_nr
, region
); ++r_nr
)
3552 if (region
&& !TEST_BIT (r_reachable
, r_nr
))
3555 fprintf (dump_file
, "Removing unreachable region %d\n", r_nr
);
3556 remove_eh_handler (region
);
3560 VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, lp_nr
, lp
); ++lp_nr
)
3561 if (lp
&& !TEST_BIT (lp_reachable
, lp_nr
))
3564 fprintf (dump_file
, "Removing unreachable landing pad %d\n", lp_nr
);
3565 remove_eh_landing_pad (lp
);
3570 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3571 dump_eh_tree (dump_file
, cfun
);
3572 fprintf (dump_file
, "\n\n");
3575 sbitmap_free (r_reachable
);
3576 sbitmap_free (lp_reachable
);
3578 #ifdef ENABLE_CHECKING
3579 verify_eh_tree (cfun
);
3583 /* Remove unreachable handlers if any landing pads have been removed after
3584 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3587 maybe_remove_unreachable_handlers (void)
3592 if (cfun
->eh
== NULL
)
3595 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3596 if (lp
&& lp
->post_landing_pad
)
3598 if (label_to_block (lp
->post_landing_pad
) == NULL
)
3600 remove_unreachable_handlers ();
3606 /* Remove regions that do not have landing pads. This assumes
3607 that remove_unreachable_handlers has already been run, and
3608 that we've just manipulated the landing pads since then. */
3611 remove_unreachable_handlers_no_lp (void)
3615 sbitmap r_reachable
;
3618 r_reachable
= sbitmap_alloc (VEC_length (eh_region
, cfun
->eh
->region_array
));
3619 sbitmap_zero (r_reachable
);
3623 gimple stmt
= last_stmt (bb
);
3625 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3626 switch (gimple_code (stmt
))
3629 SET_BIT (r_reachable
, gimple_resx_region (stmt
));
3631 case GIMPLE_EH_DISPATCH
:
3632 SET_BIT (r_reachable
, gimple_eh_dispatch_region (stmt
));
3639 for (i
= 1; VEC_iterate (eh_region
, cfun
->eh
->region_array
, i
, r
); ++i
)
3640 if (r
&& r
->landing_pads
== NULL
&& r
->type
!= ERT_MUST_NOT_THROW
3641 && !TEST_BIT (r_reachable
, i
))
3644 fprintf (dump_file
, "Removing unreachable region %d\n", i
);
3645 remove_eh_handler (r
);
3648 sbitmap_free (r_reachable
);
3651 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3652 optimisticaly split all sorts of edges, including EH edges. The
3653 optimization passes in between may not have needed them; if not,
3654 we should undo the split.
3656 Recognize this case by having one EH edge incoming to the BB and
3657 one normal edge outgoing; BB should be empty apart from the
3658 post_landing_pad label.
3660 Note that this is slightly different from the empty handler case
3661 handled by cleanup_empty_eh, in that the actual handler may yet
3662 have actual code but the landing pad has been separated from the
3663 handler. As such, cleanup_empty_eh relies on this transformation
3664 having been done first. */
3667 unsplit_eh (eh_landing_pad lp
)
3669 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3670 gimple_stmt_iterator gsi
;
3673 /* Quickly check the edge counts on BB for singularity. */
3674 if (EDGE_COUNT (bb
->preds
) != 1 || EDGE_COUNT (bb
->succs
) != 1)
3676 e_in
= EDGE_PRED (bb
, 0);
3677 e_out
= EDGE_SUCC (bb
, 0);
3679 /* Input edge must be EH and output edge must be normal. */
3680 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
3683 /* The block must be empty except for the labels and debug insns. */
3684 gsi
= gsi_after_labels (bb
);
3685 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3686 gsi_next_nondebug (&gsi
);
3687 if (!gsi_end_p (gsi
))
3690 /* The destination block must not already have a landing pad
3691 for a different region. */
3692 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3694 gimple stmt
= gsi_stmt (gsi
);
3698 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3700 lab
= gimple_label_label (stmt
);
3701 lp_nr
= EH_LANDING_PAD_NR (lab
);
3702 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3706 /* The new destination block must not already be a destination of
3707 the source block, lest we merge fallthru and eh edges and get
3708 all sorts of confused. */
3709 if (find_edge (e_in
->src
, e_out
->dest
))
3712 /* ??? We can get degenerate phis due to cfg cleanups. I would have
3713 thought this should have been cleaned up by a phicprop pass, but
3714 that doesn't appear to handle virtuals. Propagate by hand. */
3715 if (!gimple_seq_empty_p (phi_nodes (bb
)))
3717 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); )
3719 gimple use_stmt
, phi
= gsi_stmt (gsi
);
3720 tree lhs
= gimple_phi_result (phi
);
3721 tree rhs
= gimple_phi_arg_def (phi
, 0);
3722 use_operand_p use_p
;
3723 imm_use_iterator iter
;
3725 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
3727 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3728 SET_USE (use_p
, rhs
);
3731 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
3732 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
3734 remove_phi_node (&gsi
, true);
3738 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3739 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
3740 lp
->index
, e_out
->dest
->index
);
3742 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
3743 a successor edge, humor it. But do the real CFG change with the
3744 predecessor of E_OUT in order to preserve the ordering of arguments
3745 to the PHI nodes in E_OUT->DEST. */
3746 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
3747 redirect_edge_pred (e_out
, e_in
->src
);
3748 e_out
->flags
= e_in
->flags
;
3749 e_out
->probability
= e_in
->probability
;
3750 e_out
->count
= e_in
->count
;
3756 /* Examine each landing pad block and see if it matches unsplit_eh. */
3759 unsplit_all_eh (void)
3761 bool changed
= false;
3765 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3767 changed
|= unsplit_eh (lp
);
3772 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
3773 to OLD_BB to NEW_BB; return true on success, false on failure.
3775 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
3776 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
3777 Virtual PHIs may be deleted and marked for renaming. */
3780 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
3781 edge old_bb_out
, bool change_region
)
3783 gimple_stmt_iterator ngsi
, ogsi
;
3786 bitmap rename_virts
;
3787 bitmap ophi_handled
;
3789 /* The destination block must not be a regular successor for any
3790 of the preds of the landing pad. Thus, avoid turning
3800 which CFG verification would choke on. See PR45172 and PR51089. */
3801 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3802 if (find_edge (e
->src
, new_bb
))
3805 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3806 redirect_edge_var_map_clear (e
);
3808 ophi_handled
= BITMAP_ALLOC (NULL
);
3809 rename_virts
= BITMAP_ALLOC (NULL
);
3811 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
3812 for the edges we're going to move. */
3813 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
3815 gimple ophi
, nphi
= gsi_stmt (ngsi
);
3818 nresult
= gimple_phi_result (nphi
);
3819 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
3821 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
3822 the source ssa_name. */
3824 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3826 ophi
= gsi_stmt (ogsi
);
3827 if (gimple_phi_result (ophi
) == nop
)
3832 /* If we did find the corresponding PHI, copy those inputs. */
3835 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
3836 if (!has_single_use (nop
))
3838 imm_use_iterator imm_iter
;
3839 use_operand_p use_p
;
3841 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
3843 if (!gimple_debug_bind_p (USE_STMT (use_p
))
3844 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
3845 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
3849 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
3850 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3855 if ((e
->flags
& EDGE_EH
) == 0)
3857 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
3858 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
3859 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
3862 /* If we didn't find the PHI, but it's a VOP, remember to rename
3863 it later, assuming all other tests succeed. */
3864 else if (!is_gimple_reg (nresult
))
3865 bitmap_set_bit (rename_virts
, SSA_NAME_VERSION (nresult
));
3866 /* If we didn't find the PHI, and it's a real variable, we know
3867 from the fact that OLD_BB is tree_empty_eh_handler_p that the
3868 variable is unchanged from input to the block and we can simply
3869 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
3873 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
3874 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3875 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
3879 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
3880 we don't know what values from the other edges into NEW_BB to use. */
3881 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3883 gimple ophi
= gsi_stmt (ogsi
);
3884 tree oresult
= gimple_phi_result (ophi
);
3885 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
3889 /* At this point we know that the merge will succeed. Remove the PHI
3890 nodes for the virtuals that we want to rename. */
3891 if (!bitmap_empty_p (rename_virts
))
3893 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); )
3895 gimple nphi
= gsi_stmt (ngsi
);
3896 tree nresult
= gimple_phi_result (nphi
);
3897 if (bitmap_bit_p (rename_virts
, SSA_NAME_VERSION (nresult
)))
3899 mark_virtual_phi_result_for_renaming (nphi
);
3900 remove_phi_node (&ngsi
, true);
3907 /* Finally, move the edges and update the PHIs. */
3908 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
3909 if (e
->flags
& EDGE_EH
)
3911 /* ??? CFG manipluation routines do not try to update loop
3912 form on edge redirection. Do so manually here for now. */
3913 /* If we redirect a loop entry or latch edge that will either create
3914 a multiple entry loop or rotate the loop. If the loops merge
3915 we may have created a loop with multiple latches.
3916 All of this isn't easily fixed thus cancel the affected loop
3917 and mark the other loop as possibly having multiple latches. */
3919 && e
->dest
== e
->dest
->loop_father
->header
)
3921 e
->dest
->loop_father
->header
= NULL
;
3922 e
->dest
->loop_father
->latch
= NULL
;
3923 new_bb
->loop_father
->latch
= NULL
;
3924 loops_state_set (LOOPS_NEED_FIXUP
|LOOPS_MAY_HAVE_MULTIPLE_LATCHES
);
3926 redirect_eh_edge_1 (e
, new_bb
, change_region
);
3927 redirect_edge_succ (e
, new_bb
);
3928 flush_pending_stmts (e
);
3933 BITMAP_FREE (ophi_handled
);
3934 BITMAP_FREE (rename_virts
);
3938 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3939 redirect_edge_var_map_clear (e
);
3940 BITMAP_FREE (ophi_handled
);
3941 BITMAP_FREE (rename_virts
);
3945 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
3946 old region to NEW_REGION at BB. */
3949 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
3950 eh_landing_pad lp
, eh_region new_region
)
3952 gimple_stmt_iterator gsi
;
3955 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
3959 lp
->region
= new_region
;
3960 lp
->next_lp
= new_region
->landing_pads
;
3961 new_region
->landing_pads
= lp
;
3963 /* Delete the RESX that was matched within the empty handler block. */
3964 gsi
= gsi_last_bb (bb
);
3965 unlink_stmt_vdef (gsi_stmt (gsi
));
3966 gsi_remove (&gsi
, true);
3968 /* Clean up E_OUT for the fallthru. */
3969 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3970 e_out
->probability
= REG_BR_PROB_BASE
;
3973 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
3974 unsplitting than unsplit_eh was prepared to handle, e.g. when
3975 multiple incoming edges and phis are involved. */
3978 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
3980 gimple_stmt_iterator gsi
;
3983 /* We really ought not have totally lost everything following
3984 a landing pad label. Given that BB is empty, there had better
3986 gcc_assert (e_out
!= NULL
);
3988 /* The destination block must not already have a landing pad
3989 for a different region. */
3991 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3993 gimple stmt
= gsi_stmt (gsi
);
3996 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3998 lab
= gimple_label_label (stmt
);
3999 lp_nr
= EH_LANDING_PAD_NR (lab
);
4000 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4004 /* Attempt to move the PHIs into the successor block. */
4005 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
4007 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4009 "Unsplit EH landing pad %d to block %i "
4010 "(via cleanup_empty_eh).\n",
4011 lp
->index
, e_out
->dest
->index
);
4018 /* Return true if edge E_FIRST is part of an empty infinite loop
4019 or leads to such a loop through a series of single successor
4023 infinite_empty_loop_p (edge e_first
)
4025 bool inf_loop
= false;
4028 if (e_first
->dest
== e_first
->src
)
4031 e_first
->src
->aux
= (void *) 1;
4032 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
4034 gimple_stmt_iterator gsi
;
4040 e
->dest
->aux
= (void *) 1;
4041 gsi
= gsi_after_labels (e
->dest
);
4042 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4043 gsi_next_nondebug (&gsi
);
4044 if (!gsi_end_p (gsi
))
4047 e_first
->src
->aux
= NULL
;
4048 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
4049 e
->dest
->aux
= NULL
;
4054 /* Examine the block associated with LP to determine if it's an empty
4055 handler for its EH region. If so, attempt to redirect EH edges to
4056 an outer region. Return true the CFG was updated in any way. This
4057 is similar to jump forwarding, just across EH edges. */
4060 cleanup_empty_eh (eh_landing_pad lp
)
4062 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4063 gimple_stmt_iterator gsi
;
4065 eh_region new_region
;
4068 bool has_non_eh_pred
;
4072 /* There can be zero or one edges out of BB. This is the quickest test. */
4073 switch (EDGE_COUNT (bb
->succs
))
4079 e_out
= EDGE_SUCC (bb
, 0);
4085 resx
= last_stmt (bb
);
4086 if (resx
&& is_gimple_resx (resx
))
4088 if (stmt_can_throw_external (resx
))
4089 optimize_clobbers (bb
);
4090 else if (sink_clobbers (bb
))
4094 gsi
= gsi_after_labels (bb
);
4096 /* Make sure to skip debug statements. */
4097 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4098 gsi_next_nondebug (&gsi
);
4100 /* If the block is totally empty, look for more unsplitting cases. */
4101 if (gsi_end_p (gsi
))
4103 /* For the degenerate case of an infinite loop bail out. */
4104 if (infinite_empty_loop_p (e_out
))
4107 return ret
| cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
4110 /* The block should consist only of a single RESX statement, modulo a
4111 preceding call to __builtin_stack_restore if there is no outgoing
4112 edge, since the call can be eliminated in this case. */
4113 resx
= gsi_stmt (gsi
);
4114 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
4117 resx
= gsi_stmt (gsi
);
4119 if (!is_gimple_resx (resx
))
4121 gcc_assert (gsi_one_before_end_p (gsi
));
4123 /* Determine if there are non-EH edges, or resx edges into the handler. */
4124 has_non_eh_pred
= false;
4125 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4126 if (!(e
->flags
& EDGE_EH
))
4127 has_non_eh_pred
= true;
4129 /* Find the handler that's outer of the empty handler by looking at
4130 where the RESX instruction was vectored. */
4131 new_lp_nr
= lookup_stmt_eh_lp (resx
);
4132 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
4134 /* If there's no destination region within the current function,
4135 redirection is trivial via removing the throwing statements from
4136 the EH region, removing the EH edges, and allowing the block
4137 to go unreachable. */
4138 if (new_region
== NULL
)
4140 gcc_assert (e_out
== NULL
);
4141 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4142 if (e
->flags
& EDGE_EH
)
4144 gimple stmt
= last_stmt (e
->src
);
4145 remove_stmt_from_eh_lp (stmt
);
4153 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4154 to handle the abort and allow the blocks to go unreachable. */
4155 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4157 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4158 if (e
->flags
& EDGE_EH
)
4160 gimple stmt
= last_stmt (e
->src
);
4161 remove_stmt_from_eh_lp (stmt
);
4162 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4170 /* Try to redirect the EH edges and merge the PHIs into the destination
4171 landing pad block. If the merge succeeds, we'll already have redirected
4172 all the EH edges. The handler itself will go unreachable if there were
4174 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4177 /* Finally, if all input edges are EH edges, then we can (potentially)
4178 reduce the number of transfers from the runtime by moving the landing
4179 pad from the original region to the new region. This is a win when
4180 we remove the last CLEANUP region along a particular exception
4181 propagation path. Since nothing changes except for the region with
4182 which the landing pad is associated, the PHI nodes do not need to be
4184 if (!has_non_eh_pred
)
4186 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4187 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4188 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4189 lp
->index
, new_region
->index
);
4191 /* ??? The CFG didn't change, but we may have rendered the
4192 old EH region unreachable. Trigger a cleanup there. */
4199 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4200 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4201 remove_eh_landing_pad (lp
);
4205 /* Do a post-order traversal of the EH region tree. Examine each
4206 post_landing_pad block and see if we can eliminate it as empty. */
4209 cleanup_all_empty_eh (void)
4211 bool changed
= false;
4215 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
4217 changed
|= cleanup_empty_eh (lp
);
4222 /* Perform cleanups and lowering of exception handling
4223 1) cleanups regions with handlers doing nothing are optimized out
4224 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4225 3) Info about regions that are containing instructions, and regions
4226 reachable via local EH edges is collected
4227 4) Eh tree is pruned for regions no longer neccesary.
4229 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4230 Unify those that have the same failure decl and locus.
4234 execute_cleanup_eh_1 (void)
4236 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4237 looking up unreachable landing pads. */
4238 remove_unreachable_handlers ();
4240 /* Watch out for the region tree vanishing due to all unreachable. */
4241 if (cfun
->eh
->region_tree
&& optimize
)
4243 bool changed
= false;
4245 changed
|= unsplit_all_eh ();
4246 changed
|= cleanup_all_empty_eh ();
4250 free_dominance_info (CDI_DOMINATORS
);
4251 free_dominance_info (CDI_POST_DOMINATORS
);
4253 /* We delayed all basic block deletion, as we may have performed
4254 cleanups on EH edges while non-EH edges were still present. */
4255 delete_unreachable_blocks ();
4257 /* We manipulated the landing pads. Remove any region that no
4258 longer has a landing pad. */
4259 remove_unreachable_handlers_no_lp ();
4261 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4269 execute_cleanup_eh (void)
4271 int ret
= execute_cleanup_eh_1 ();
4273 /* If the function no longer needs an EH personality routine
4274 clear it. This exposes cross-language inlining opportunities
4275 and avoids references to a never defined personality routine. */
4276 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4277 && function_needs_eh_personality (cfun
) != eh_personality_lang
)
4278 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4284 gate_cleanup_eh (void)
4286 return cfun
->eh
!= NULL
&& cfun
->eh
->region_tree
!= NULL
;
4289 struct gimple_opt_pass pass_cleanup_eh
= {
4292 "ehcleanup", /* name */
4293 gate_cleanup_eh
, /* gate */
4294 execute_cleanup_eh
, /* execute */
4297 0, /* static_pass_number */
4298 TV_TREE_EH
, /* tv_id */
4299 PROP_gimple_lcf
, /* properties_required */
4300 0, /* properties_provided */
4301 0, /* properties_destroyed */
4302 0, /* todo_flags_start */
4303 0 /* todo_flags_finish */
4307 /* Verify that BB containing STMT as the last statement, has precisely the
4308 edge that make_eh_edges would create. */
4311 verify_eh_edges (gimple stmt
)
4313 basic_block bb
= gimple_bb (stmt
);
4314 eh_landing_pad lp
= NULL
;
4319 lp_nr
= lookup_stmt_eh_lp (stmt
);
4321 lp
= get_eh_landing_pad_from_number (lp_nr
);
4324 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4326 if (e
->flags
& EDGE_EH
)
4330 error ("BB %i has multiple EH edges", bb
->index
);
4342 error ("BB %i can not throw but has an EH edge", bb
->index
);
4348 if (!stmt_could_throw_p (stmt
))
4350 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4354 if (eh_edge
== NULL
)
4356 error ("BB %i is missing an EH edge", bb
->index
);
4360 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
4362 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4369 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4372 verify_eh_dispatch_edge (gimple stmt
)
4376 basic_block src
, dst
;
4377 bool want_fallthru
= true;
4381 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4382 src
= gimple_bb (stmt
);
4384 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4385 gcc_assert (e
->aux
== NULL
);
4390 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4392 dst
= label_to_block (c
->label
);
4393 e
= find_edge (src
, dst
);
4396 error ("BB %i is missing an edge", src
->index
);
4401 /* A catch-all handler doesn't have a fallthru. */
4402 if (c
->type_list
== NULL
)
4404 want_fallthru
= false;
4410 case ERT_ALLOWED_EXCEPTIONS
:
4411 dst
= label_to_block (r
->u
.allowed
.label
);
4412 e
= find_edge (src
, dst
);
4415 error ("BB %i is missing an edge", src
->index
);
4426 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4428 if (e
->flags
& EDGE_FALLTHRU
)
4430 if (fall_edge
!= NULL
)
4432 error ("BB %i too many fallthru edges", src
->index
);
4441 error ("BB %i has incorrect edge", src
->index
);
4445 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4447 error ("BB %i has incorrect fallthru edge", src
->index
);