1 /* Implements exception handling.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001 Free Software Foundation, Inc.
4 Contributed by Mike Stump <mrs@cygnus.com>.
6 This file is part of GNU CC.
8 GNU CC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GNU CC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GNU CC; see the file COPYING. If not, write to
20 the Free Software Foundation, 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
24 /* An exception is an event that can be signaled from within a
25 function. This event can then be "caught" or "trapped" by the
26 callers of this function. This potentially allows program flow to
27 be transferred to any arbitrary code associated with a function call
28 several levels up the stack.
30 The intended use for this mechanism is for signaling "exceptional
31 events" in an out-of-band fashion, hence its name. The C++ language
32 (and many other OO-styled or functional languages) practically
33 requires such a mechanism, as otherwise it becomes very difficult
34 or even impossible to signal failure conditions in complex
35 situations. The traditional C++ example is when an error occurs in
36 the process of constructing an object; without such a mechanism, it
37 is impossible to signal that the error occurs without adding global
38 state variables and error checks around every object construction.
40 The act of causing this event to occur is referred to as "throwing
41 an exception". (Alternate terms include "raising an exception" or
42 "signaling an exception".) The term "throw" is used because control
43 is returned to the callers of the function that is signaling the
44 exception, and thus there is the concept of "throwing" the
45 exception up the call stack.
47 [ Add updated documentation on how to use this. ] */
57 #include "insn-config.h"
59 #include "integrate.h"
60 #include "hard-reg-set.h"
61 #include "basic-block.h"
63 #include "dwarf2asm.h"
64 #include "dwarf2out.h"
73 /* Provide defaults for stuff that may not be defined when using
75 #ifndef EH_RETURN_STACKADJ_RTX
76 #define EH_RETURN_STACKADJ_RTX 0
78 #ifndef EH_RETURN_HANDLER_RTX
79 #define EH_RETURN_HANDLER_RTX 0
81 #ifndef EH_RETURN_DATA_REGNO
82 #define EH_RETURN_DATA_REGNO(N) INVALID_REGNUM
86 /* Nonzero means enable synchronous exceptions for non-call instructions. */
87 int flag_non_call_exceptions;
89 /* Protect cleanup actions with must-not-throw regions, with a call
90 to the given failure handler. */
91 tree (*lang_protect_cleanup_actions) PARAMS ((void));
93 /* Return true if type A catches type B. */
94 int (*lang_eh_type_covers) PARAMS ((tree a, tree b));
96 /* Map a type to a runtime object to match type. */
97 tree (*lang_eh_runtime_type) PARAMS ((tree));
99 /* A list of labels used for exception handlers. */
100 rtx exception_handler_labels;
102 static int call_site_base;
103 static unsigned int sjlj_funcdef_number;
104 static htab_t type_to_runtime_map;
106 /* Describe the SjLj_Function_Context structure. */
107 static tree sjlj_fc_type_node;
108 static int sjlj_fc_call_site_ofs;
109 static int sjlj_fc_data_ofs;
110 static int sjlj_fc_personality_ofs;
111 static int sjlj_fc_lsda_ofs;
112 static int sjlj_fc_jbuf_ofs;
114 /* Describes one exception region. */
117 /* The immediately surrounding region. */
118 struct eh_region *outer;
120 /* The list of immediately contained regions. */
121 struct eh_region *inner;
122 struct eh_region *next_peer;
124 /* An identifier for this region. */
127 /* Each region does exactly one thing. */
133 ERT_ALLOWED_EXCEPTIONS,
139 /* Holds the action to perform based on the preceeding type. */
141 /* A list of catch blocks, a surrounding try block,
142 and the label for continuing after a catch. */
144 struct eh_region *catch;
145 struct eh_region *last_catch;
146 struct eh_region *prev_try;
150 /* The list through the catch handlers, the type object
151 matched, and a pointer to the generated code. */
153 struct eh_region *next_catch;
154 struct eh_region *prev_catch;
159 /* A tree_list of allowed types. */
165 /* The type given by a call to "throw foo();", or discovered
171 /* Retain the cleanup expression even after expansion so that
172 we can match up fixup regions. */
177 /* The real region (by expression and by pointer) that fixup code
181 struct eh_region *real_region;
185 /* Entry point for this region's handler before landing pads are built. */
188 /* Entry point for this region's handler from the runtime eh library. */
191 /* Entry point for this region's handler from an inner region. */
192 rtx post_landing_pad;
194 /* The RESX insn for handing off control to the next outermost handler,
199 /* Used to save exception status for each function. */
202 /* The tree of all regions for this function. */
203 struct eh_region *region_tree;
205 /* The same information as an indexable array. */
206 struct eh_region **region_array;
208 /* The most recently open region. */
209 struct eh_region *cur_region;
211 /* This is the region for which we are processing catch blocks. */
212 struct eh_region *try_region;
214 /* A stack (TREE_LIST) of lists of handlers. The TREE_VALUE of each
215 node is itself a TREE_CHAINed list of handlers for regions that
216 are not yet closed. The TREE_VALUE of each entry contains the
217 handler for the corresponding entry on the ehstack. */
223 int built_landing_pads;
224 int last_region_number;
226 varray_type ttype_data;
227 varray_type ehspec_data;
228 varray_type action_record_data;
230 struct call_site_record
235 int call_site_data_used;
236 int call_site_data_size;
247 static void mark_eh_region PARAMS ((struct eh_region *));
249 static int t2r_eq PARAMS ((const PTR,
251 static hashval_t t2r_hash PARAMS ((const PTR));
252 static int t2r_mark_1 PARAMS ((PTR *, PTR));
253 static void t2r_mark PARAMS ((PTR));
254 static void add_type_for_runtime PARAMS ((tree));
255 static tree lookup_type_for_runtime PARAMS ((tree));
257 static struct eh_region *expand_eh_region_end PARAMS ((void));
259 static rtx get_exception_filter PARAMS ((struct function *));
261 static void collect_eh_region_array PARAMS ((void));
262 static void resolve_fixup_regions PARAMS ((void));
263 static void remove_fixup_regions PARAMS ((void));
264 static void convert_from_eh_region_ranges_1 PARAMS ((rtx *, int *, int));
266 static struct eh_region *duplicate_eh_region_1 PARAMS ((struct eh_region *,
267 struct inline_remap *));
268 static void duplicate_eh_region_2 PARAMS ((struct eh_region *,
269 struct eh_region **));
270 static int ttypes_filter_eq PARAMS ((const PTR,
272 static hashval_t ttypes_filter_hash PARAMS ((const PTR));
273 static int ehspec_filter_eq PARAMS ((const PTR,
275 static hashval_t ehspec_filter_hash PARAMS ((const PTR));
276 static int add_ttypes_entry PARAMS ((htab_t, tree));
277 static int add_ehspec_entry PARAMS ((htab_t, htab_t,
279 static void assign_filter_values PARAMS ((void));
280 static void build_post_landing_pads PARAMS ((void));
281 static void connect_post_landing_pads PARAMS ((void));
282 static void dw2_build_landing_pads PARAMS ((void));
285 static bool sjlj_find_directly_reachable_regions
286 PARAMS ((struct sjlj_lp_info *));
287 static void sjlj_assign_call_site_values
288 PARAMS ((rtx, struct sjlj_lp_info *));
289 static void sjlj_mark_call_sites
290 PARAMS ((struct sjlj_lp_info *));
291 static void sjlj_emit_function_enter PARAMS ((rtx));
292 static void sjlj_emit_function_exit PARAMS ((void));
293 static void sjlj_emit_dispatch_table
294 PARAMS ((rtx, struct sjlj_lp_info *));
295 static void sjlj_build_landing_pads PARAMS ((void));
297 static void remove_exception_handler_label PARAMS ((rtx));
298 static void remove_eh_handler PARAMS ((struct eh_region *));
300 struct reachable_info;
302 /* The return value of reachable_next_level. */
305 /* The given exception is not processed by the given region. */
307 /* The given exception may need processing by the given region. */
309 /* The given exception is completely processed by the given region. */
311 /* The given exception is completely processed by the runtime. */
315 static int check_handled PARAMS ((tree, tree));
316 static void add_reachable_handler
317 PARAMS ((struct reachable_info *, struct eh_region *,
318 struct eh_region *));
319 static enum reachable_code reachable_next_level
320 PARAMS ((struct eh_region *, tree, struct reachable_info *));
322 static int action_record_eq PARAMS ((const PTR,
324 static hashval_t action_record_hash PARAMS ((const PTR));
325 static int add_action_record PARAMS ((htab_t, int, int));
326 static int collect_one_action_chain PARAMS ((htab_t,
327 struct eh_region *));
328 static int add_call_site PARAMS ((rtx, int));
330 static void push_uleb128 PARAMS ((varray_type *,
332 static void push_sleb128 PARAMS ((varray_type *, int));
333 #ifndef HAVE_AS_LEB128
334 static int dw2_size_of_call_site_table PARAMS ((void));
335 static int sjlj_size_of_call_site_table PARAMS ((void));
337 static void dw2_output_call_site_table PARAMS ((void));
338 static void sjlj_output_call_site_table PARAMS ((void));
341 /* Routine to see if exception handling is turned on.
342 DO_WARN is non-zero if we want to inform the user that exception
343 handling is turned off.
345 This is used to ensure that -fexceptions has been specified if the
346 compiler tries to use any exception-specific functions. */
352 if (! flag_exceptions)
354 static int warned = 0;
355 if (! warned && do_warn)
357 error ("exception handling disabled, use -fexceptions to enable");
369 ggc_add_rtx_root (&exception_handler_labels, 1);
371 if (! flag_exceptions)
374 type_to_runtime_map = htab_create (31, t2r_hash, t2r_eq, NULL);
375 ggc_add_root (&type_to_runtime_map, 1, sizeof (htab_t), t2r_mark);
377 /* Create the SjLj_Function_Context structure. This should match
378 the definition in unwind-sjlj.c. */
379 if (USING_SJLJ_EXCEPTIONS)
381 tree f_jbuf, f_per, f_lsda, f_prev, f_cs, f_data, tmp;
383 sjlj_fc_type_node = make_lang_type (RECORD_TYPE);
384 ggc_add_tree_root (&sjlj_fc_type_node, 1);
386 f_prev = build_decl (FIELD_DECL, get_identifier ("__prev"),
387 build_pointer_type (sjlj_fc_type_node));
388 DECL_FIELD_CONTEXT (f_prev) = sjlj_fc_type_node;
390 f_cs = build_decl (FIELD_DECL, get_identifier ("__call_site"),
392 DECL_FIELD_CONTEXT (f_cs) = sjlj_fc_type_node;
394 tmp = build_index_type (build_int_2 (4 - 1, 0));
395 tmp = build_array_type (type_for_mode (word_mode, 1), tmp);
396 f_data = build_decl (FIELD_DECL, get_identifier ("__data"), tmp);
397 DECL_FIELD_CONTEXT (f_data) = sjlj_fc_type_node;
399 f_per = build_decl (FIELD_DECL, get_identifier ("__personality"),
401 DECL_FIELD_CONTEXT (f_per) = sjlj_fc_type_node;
403 f_lsda = build_decl (FIELD_DECL, get_identifier ("__lsda"),
405 DECL_FIELD_CONTEXT (f_lsda) = sjlj_fc_type_node;
407 #ifdef DONT_USE_BUILTIN_SETJMP
409 tmp = build_int_2 (JMP_BUF_SIZE - 1, 0);
411 /* Should be large enough for most systems, if it is not,
412 JMP_BUF_SIZE should be defined with the proper value. It will
413 also tend to be larger than necessary for most systems, a more
414 optimal port will define JMP_BUF_SIZE. */
415 tmp = build_int_2 (FIRST_PSEUDO_REGISTER + 2 - 1, 0);
418 /* This is 2 for builtin_setjmp, plus whatever the target requires
419 via STACK_SAVEAREA_MODE (SAVE_NONLOCAL). */
420 tmp = build_int_2 ((GET_MODE_SIZE (STACK_SAVEAREA_MODE (SAVE_NONLOCAL))
421 / GET_MODE_SIZE (Pmode)) + 2 - 1, 0);
423 tmp = build_index_type (tmp);
424 tmp = build_array_type (ptr_type_node, tmp);
425 f_jbuf = build_decl (FIELD_DECL, get_identifier ("__jbuf"), tmp);
426 #ifdef DONT_USE_BUILTIN_SETJMP
427 /* We don't know what the alignment requirements of the
428 runtime's jmp_buf has. Overestimate. */
429 DECL_ALIGN (f_jbuf) = BIGGEST_ALIGNMENT;
430 DECL_USER_ALIGN (f_jbuf) = 1;
432 DECL_FIELD_CONTEXT (f_jbuf) = sjlj_fc_type_node;
434 TYPE_FIELDS (sjlj_fc_type_node) = f_prev;
435 TREE_CHAIN (f_prev) = f_cs;
436 TREE_CHAIN (f_cs) = f_data;
437 TREE_CHAIN (f_data) = f_per;
438 TREE_CHAIN (f_per) = f_lsda;
439 TREE_CHAIN (f_lsda) = f_jbuf;
441 layout_type (sjlj_fc_type_node);
443 /* Cache the interesting field offsets so that we have
444 easy access from rtl. */
445 sjlj_fc_call_site_ofs
446 = (tree_low_cst (DECL_FIELD_OFFSET (f_cs), 1)
447 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_cs), 1) / BITS_PER_UNIT);
449 = (tree_low_cst (DECL_FIELD_OFFSET (f_data), 1)
450 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_data), 1) / BITS_PER_UNIT);
451 sjlj_fc_personality_ofs
452 = (tree_low_cst (DECL_FIELD_OFFSET (f_per), 1)
453 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_per), 1) / BITS_PER_UNIT);
455 = (tree_low_cst (DECL_FIELD_OFFSET (f_lsda), 1)
456 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_lsda), 1) / BITS_PER_UNIT);
458 = (tree_low_cst (DECL_FIELD_OFFSET (f_jbuf), 1)
459 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_jbuf), 1) / BITS_PER_UNIT);
464 init_eh_for_function ()
466 cfun->eh = (struct eh_status *) xcalloc (1, sizeof (struct eh_status));
469 /* Mark EH for GC. */
472 mark_eh_region (region)
473 struct eh_region *region;
478 switch (region->type)
481 ggc_mark_tree (region->u.cleanup.exp);
484 ggc_mark_rtx (region->u.try.continue_label);
487 ggc_mark_tree (region->u.catch.type);
489 case ERT_ALLOWED_EXCEPTIONS:
490 ggc_mark_tree (region->u.allowed.type_list);
492 case ERT_MUST_NOT_THROW:
495 ggc_mark_tree (region->u.throw.type);
498 ggc_mark_tree (region->u.fixup.cleanup_exp);
504 ggc_mark_rtx (region->label);
505 ggc_mark_rtx (region->resume);
506 ggc_mark_rtx (region->landing_pad);
507 ggc_mark_rtx (region->post_landing_pad);
512 struct eh_status *eh;
519 /* If we've called collect_eh_region_array, use it. Otherwise walk
520 the tree non-recursively. */
521 if (eh->region_array)
523 for (i = eh->last_region_number; i > 0; --i)
525 struct eh_region *r = eh->region_array[i];
526 if (r && r->region_number == i)
530 else if (eh->region_tree)
532 struct eh_region *r = eh->region_tree;
538 else if (r->next_peer)
546 } while (r->next_peer == NULL);
553 ggc_mark_tree (eh->protect_list);
554 ggc_mark_rtx (eh->filter);
555 ggc_mark_rtx (eh->exc_ptr);
556 ggc_mark_tree_varray (eh->ttype_data);
558 if (eh->call_site_data)
560 for (i = eh->call_site_data_used - 1; i >= 0; --i)
561 ggc_mark_rtx (eh->call_site_data[i].landing_pad);
564 ggc_mark_rtx (eh->ehr_stackadj);
565 ggc_mark_rtx (eh->ehr_handler);
566 ggc_mark_rtx (eh->ehr_label);
568 ggc_mark_rtx (eh->sjlj_fc);
569 ggc_mark_rtx (eh->sjlj_exit_after);
576 struct eh_status *eh = f->eh;
578 if (eh->region_array)
581 for (i = eh->last_region_number; i > 0; --i)
583 struct eh_region *r = eh->region_array[i];
584 /* Mind we don't free a region struct more than once. */
585 if (r && r->region_number == i)
588 free (eh->region_array);
590 else if (eh->region_tree)
592 struct eh_region *next, *r = eh->region_tree;
597 else if (r->next_peer)
611 } while (r->next_peer == NULL);
620 VARRAY_FREE (eh->ttype_data);
621 VARRAY_FREE (eh->ehspec_data);
622 VARRAY_FREE (eh->action_record_data);
623 if (eh->call_site_data)
624 free (eh->call_site_data);
631 /* Start an exception handling region. All instructions emitted
632 after this point are considered to be part of the region until
633 expand_eh_region_end is invoked. */
636 expand_eh_region_start ()
638 struct eh_region *new_region;
639 struct eh_region *cur_region;
645 /* Insert a new blank region as a leaf in the tree. */
646 new_region = (struct eh_region *) xcalloc (1, sizeof (*new_region));
647 cur_region = cfun->eh->cur_region;
648 new_region->outer = cur_region;
651 new_region->next_peer = cur_region->inner;
652 cur_region->inner = new_region;
656 new_region->next_peer = cfun->eh->region_tree;
657 cfun->eh->region_tree = new_region;
659 cfun->eh->cur_region = new_region;
661 /* Create a note marking the start of this region. */
662 new_region->region_number = ++cfun->eh->last_region_number;
663 note = emit_note (NULL, NOTE_INSN_EH_REGION_BEG);
664 NOTE_EH_HANDLER (note) = new_region->region_number;
667 /* Common code to end a region. Returns the region just ended. */
669 static struct eh_region *
670 expand_eh_region_end ()
672 struct eh_region *cur_region = cfun->eh->cur_region;
675 /* Create a nute marking the end of this region. */
676 note = emit_note (NULL, NOTE_INSN_EH_REGION_END);
677 NOTE_EH_HANDLER (note) = cur_region->region_number;
680 cfun->eh->cur_region = cur_region->outer;
685 /* End an exception handling region for a cleanup. HANDLER is an
686 expression to expand for the cleanup. */
689 expand_eh_region_end_cleanup (handler)
692 struct eh_region *region;
693 tree protect_cleanup_actions;
700 region = expand_eh_region_end ();
701 region->type = ERT_CLEANUP;
702 region->label = gen_label_rtx ();
703 region->u.cleanup.exp = handler;
705 around_label = gen_label_rtx ();
706 emit_jump (around_label);
708 emit_label (region->label);
710 /* Give the language a chance to specify an action to be taken if an
711 exception is thrown that would propogate out of the HANDLER. */
712 protect_cleanup_actions
713 = (lang_protect_cleanup_actions
714 ? (*lang_protect_cleanup_actions) ()
717 if (protect_cleanup_actions)
718 expand_eh_region_start ();
720 /* In case this cleanup involves an inline destructor with a try block in
721 it, we need to save the EH return data registers around it. */
722 data_save[0] = gen_reg_rtx (Pmode);
723 emit_move_insn (data_save[0], get_exception_pointer (cfun));
724 data_save[1] = gen_reg_rtx (word_mode);
725 emit_move_insn (data_save[1], get_exception_filter (cfun));
727 expand_expr (handler, const0_rtx, VOIDmode, 0);
729 emit_move_insn (cfun->eh->exc_ptr, data_save[0]);
730 emit_move_insn (cfun->eh->filter, data_save[1]);
732 if (protect_cleanup_actions)
733 expand_eh_region_end_must_not_throw (protect_cleanup_actions);
735 /* We need any stack adjustment complete before the around_label. */
736 do_pending_stack_adjust ();
738 /* We delay the generation of the _Unwind_Resume until we generate
739 landing pads. We emit a marker here so as to get good control
740 flow data in the meantime. */
742 = emit_jump_insn (gen_rtx_RESX (VOIDmode, region->region_number));
745 emit_label (around_label);
748 /* End an exception handling region for a try block, and prepares
749 for subsequent calls to expand_start_catch. */
752 expand_start_all_catch ()
754 struct eh_region *region;
759 region = expand_eh_region_end ();
760 region->type = ERT_TRY;
761 region->u.try.prev_try = cfun->eh->try_region;
762 region->u.try.continue_label = gen_label_rtx ();
764 cfun->eh->try_region = region;
766 emit_jump (region->u.try.continue_label);
769 /* Begin a catch clause. TYPE is the type caught, or null if this is
770 a catch-all clause. */
773 expand_start_catch (type)
776 struct eh_region *t, *c, *l;
782 add_type_for_runtime (type);
783 expand_eh_region_start ();
785 t = cfun->eh->try_region;
786 c = cfun->eh->cur_region;
788 c->u.catch.type = type;
789 c->label = gen_label_rtx ();
791 l = t->u.try.last_catch;
792 c->u.catch.prev_catch = l;
794 l->u.catch.next_catch = c;
797 t->u.try.last_catch = c;
799 emit_label (c->label);
802 /* End a catch clause. Control will resume after the try/catch block. */
807 struct eh_region *try_region, *catch_region;
812 catch_region = expand_eh_region_end ();
813 try_region = cfun->eh->try_region;
815 emit_jump (try_region->u.try.continue_label);
818 /* End a sequence of catch handlers for a try block. */
821 expand_end_all_catch ()
823 struct eh_region *try_region;
828 try_region = cfun->eh->try_region;
829 cfun->eh->try_region = try_region->u.try.prev_try;
831 emit_label (try_region->u.try.continue_label);
834 /* End an exception region for an exception type filter. ALLOWED is a
835 TREE_LIST of types to be matched by the runtime. FAILURE is an
836 expression to invoke if a mismatch ocurrs. */
839 expand_eh_region_end_allowed (allowed, failure)
840 tree allowed, failure;
842 struct eh_region *region;
848 region = expand_eh_region_end ();
849 region->type = ERT_ALLOWED_EXCEPTIONS;
850 region->u.allowed.type_list = allowed;
851 region->label = gen_label_rtx ();
853 for (; allowed ; allowed = TREE_CHAIN (allowed))
854 add_type_for_runtime (TREE_VALUE (allowed));
856 /* We must emit the call to FAILURE here, so that if this function
857 throws a different exception, that it will be processed by the
860 around_label = gen_label_rtx ();
861 emit_jump (around_label);
863 emit_label (region->label);
864 expand_expr (failure, const0_rtx, VOIDmode, EXPAND_NORMAL);
865 /* We must adjust the stack before we reach the AROUND_LABEL because
866 the call to FAILURE does not occur on all paths to the
868 do_pending_stack_adjust ();
870 emit_label (around_label);
873 /* End an exception region for a must-not-throw filter. FAILURE is an
874 expression invoke if an uncaught exception propagates this far.
876 This is conceptually identical to expand_eh_region_end_allowed with
877 an empty allowed list (if you passed "std::terminate" instead of
878 "__cxa_call_unexpected"), but they are represented differently in
882 expand_eh_region_end_must_not_throw (failure)
885 struct eh_region *region;
891 region = expand_eh_region_end ();
892 region->type = ERT_MUST_NOT_THROW;
893 region->label = gen_label_rtx ();
895 /* We must emit the call to FAILURE here, so that if this function
896 throws a different exception, that it will be processed by the
899 around_label = gen_label_rtx ();
900 emit_jump (around_label);
902 emit_label (region->label);
903 expand_expr (failure, const0_rtx, VOIDmode, EXPAND_NORMAL);
905 emit_label (around_label);
908 /* End an exception region for a throw. No handling goes on here,
909 but it's the easiest way for the front-end to indicate what type
913 expand_eh_region_end_throw (type)
916 struct eh_region *region;
921 region = expand_eh_region_end ();
922 region->type = ERT_THROW;
923 region->u.throw.type = type;
926 /* End a fixup region. Within this region the cleanups for the immediately
927 enclosing region are _not_ run. This is used for goto cleanup to avoid
928 destroying an object twice.
930 This would be an extraordinarily simple prospect, were it not for the
931 fact that we don't actually know what the immediately enclosing region
932 is. This surprising fact is because expand_cleanups is currently
933 generating a sequence that it will insert somewhere else. We collect
934 the proper notion of "enclosing" in convert_from_eh_region_ranges. */
937 expand_eh_region_end_fixup (handler)
940 struct eh_region *fixup;
945 fixup = expand_eh_region_end ();
946 fixup->type = ERT_FIXUP;
947 fixup->u.fixup.cleanup_exp = handler;
950 /* Return an rtl expression for a pointer to the exception object
954 get_exception_pointer (fun)
955 struct function *fun;
957 rtx exc_ptr = fun->eh->exc_ptr;
958 if (fun == cfun && ! exc_ptr)
960 exc_ptr = gen_reg_rtx (Pmode);
961 fun->eh->exc_ptr = exc_ptr;
966 /* Return an rtl expression for the exception dispatch filter
970 get_exception_filter (fun)
971 struct function *fun;
973 rtx filter = fun->eh->filter;
974 if (fun == cfun && ! filter)
976 filter = gen_reg_rtx (word_mode);
977 fun->eh->filter = filter;
982 /* Begin a region that will contain entries created with
983 add_partial_entry. */
986 begin_protect_partials ()
988 /* Push room for a new list. */
989 cfun->eh->protect_list
990 = tree_cons (NULL_TREE, NULL_TREE, cfun->eh->protect_list);
993 /* Start a new exception region for a region of code that has a
994 cleanup action and push the HANDLER for the region onto
995 protect_list. All of the regions created with add_partial_entry
996 will be ended when end_protect_partials is invoked. */
999 add_partial_entry (handler)
1002 expand_eh_region_start ();
1004 /* ??? This comment was old before the most recent rewrite. We
1005 really ought to fix the callers at some point. */
1006 /* For backwards compatibility, we allow callers to omit calls to
1007 begin_protect_partials for the outermost region. So, we must
1008 explicitly do so here. */
1009 if (!cfun->eh->protect_list)
1010 begin_protect_partials ();
1012 /* Add this entry to the front of the list. */
1013 TREE_VALUE (cfun->eh->protect_list)
1014 = tree_cons (NULL_TREE, handler, TREE_VALUE (cfun->eh->protect_list));
1017 /* End all the pending exception regions on protect_list. */
1020 end_protect_partials ()
1024 /* ??? This comment was old before the most recent rewrite. We
1025 really ought to fix the callers at some point. */
1026 /* For backwards compatibility, we allow callers to omit the call to
1027 begin_protect_partials for the outermost region. So,
1028 PROTECT_LIST may be NULL. */
1029 if (!cfun->eh->protect_list)
1032 /* Pop the topmost entry. */
1033 t = TREE_VALUE (cfun->eh->protect_list);
1034 cfun->eh->protect_list = TREE_CHAIN (cfun->eh->protect_list);
1036 /* End all the exception regions. */
1037 for (; t; t = TREE_CHAIN (t))
1038 expand_eh_region_end_cleanup (TREE_VALUE (t));
1042 /* This section is for the exception handling specific optimization pass. */
1044 /* Random access the exception region tree. It's just as simple to
1045 collect the regions this way as in expand_eh_region_start, but
1046 without having to realloc memory. */
1049 collect_eh_region_array ()
1051 struct eh_region **array, *i;
1053 i = cfun->eh->region_tree;
1057 array = xcalloc (cfun->eh->last_region_number + 1, sizeof (*array));
1058 cfun->eh->region_array = array;
1062 array[i->region_number] = i;
1064 /* If there are sub-regions, process them. */
1067 /* If there are peers, process them. */
1068 else if (i->next_peer)
1070 /* Otherwise, step back up the tree to the next peer. */
1077 } while (i->next_peer == NULL);
1084 resolve_fixup_regions ()
1086 int i, j, n = cfun->eh->last_region_number;
1088 for (i = 1; i <= n; ++i)
1090 struct eh_region *fixup = cfun->eh->region_array[i];
1091 struct eh_region *cleanup = 0;
1093 if (! fixup || fixup->type != ERT_FIXUP)
1096 for (j = 1; j <= n; ++j)
1098 cleanup = cfun->eh->region_array[j];
1099 if (cleanup->type == ERT_CLEANUP
1100 && cleanup->u.cleanup.exp == fixup->u.fixup.cleanup_exp)
1106 fixup->u.fixup.real_region = cleanup->outer;
1110 /* Now that we've discovered what region actually encloses a fixup,
1111 we can shuffle pointers and remove them from the tree. */
1114 remove_fixup_regions ()
1118 struct eh_region *fixup;
1120 /* Walk the insn chain and adjust the REG_EH_REGION numbers
1121 for instructions referencing fixup regions. This is only
1122 strictly necessary for fixup regions with no parent, but
1123 doesn't hurt to do it for all regions. */
1124 for (insn = get_insns(); insn ; insn = NEXT_INSN (insn))
1126 && (note = find_reg_note (insn, REG_EH_REGION, NULL))
1127 && INTVAL (XEXP (note, 0)) > 0
1128 && (fixup = cfun->eh->region_array[INTVAL (XEXP (note, 0))])
1129 && fixup->type == ERT_FIXUP)
1131 if (fixup->u.fixup.real_region)
1132 XEXP (note, 0) = GEN_INT (fixup->u.fixup.real_region->region_number);
1134 remove_note (insn, note);
1137 /* Remove the fixup regions from the tree. */
1138 for (i = cfun->eh->last_region_number; i > 0; --i)
1140 fixup = cfun->eh->region_array[i];
1144 /* Allow GC to maybe free some memory. */
1145 if (fixup->type == ERT_CLEANUP)
1146 fixup->u.cleanup.exp = NULL_TREE;
1148 if (fixup->type != ERT_FIXUP)
1153 struct eh_region *parent, *p, **pp;
1155 parent = fixup->u.fixup.real_region;
1157 /* Fix up the children's parent pointers; find the end of
1159 for (p = fixup->inner; ; p = p->next_peer)
1166 /* In the tree of cleanups, only outer-inner ordering matters.
1167 So link the children back in anywhere at the correct level. */
1169 pp = &parent->inner;
1171 pp = &cfun->eh->region_tree;
1174 fixup->inner = NULL;
1177 remove_eh_handler (fixup);
1181 /* Turn NOTE_INSN_EH_REGION notes into REG_EH_REGION notes for each
1182 can_throw instruction in the region. */
1185 convert_from_eh_region_ranges_1 (pinsns, orig_sp, cur)
1193 for (insn = *pinsns; insn ; insn = next)
1195 next = NEXT_INSN (insn);
1196 if (GET_CODE (insn) == NOTE)
1198 int kind = NOTE_LINE_NUMBER (insn);
1199 if (kind == NOTE_INSN_EH_REGION_BEG
1200 || kind == NOTE_INSN_EH_REGION_END)
1202 if (kind == NOTE_INSN_EH_REGION_BEG)
1204 struct eh_region *r;
1207 cur = NOTE_EH_HANDLER (insn);
1209 r = cfun->eh->region_array[cur];
1210 if (r->type == ERT_FIXUP)
1212 r = r->u.fixup.real_region;
1213 cur = r ? r->region_number : 0;
1215 else if (r->type == ERT_CATCH)
1218 cur = r ? r->region_number : 0;
1224 /* Removing the first insn of a CALL_PLACEHOLDER sequence
1225 requires extra care to adjust sequence start. */
1226 if (insn == *pinsns)
1232 else if (INSN_P (insn))
1235 && ! find_reg_note (insn, REG_EH_REGION, NULL_RTX)
1236 /* Calls can always potentially throw exceptions, unless
1237 they have a REG_EH_REGION note with a value of 0 or less.
1238 Which should be the only possible kind so far. */
1239 && (GET_CODE (insn) == CALL_INSN
1240 /* If we wanted exceptions for non-call insns, then
1241 any may_trap_p instruction could throw. */
1242 || (flag_non_call_exceptions
1243 && GET_CODE (PATTERN (insn)) != CLOBBER
1244 && GET_CODE (PATTERN (insn)) != USE
1245 && may_trap_p (PATTERN (insn)))))
1247 REG_NOTES (insn) = alloc_EXPR_LIST (REG_EH_REGION, GEN_INT (cur),
1251 if (GET_CODE (insn) == CALL_INSN
1252 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
1254 convert_from_eh_region_ranges_1 (&XEXP (PATTERN (insn), 0),
1256 convert_from_eh_region_ranges_1 (&XEXP (PATTERN (insn), 1),
1258 convert_from_eh_region_ranges_1 (&XEXP (PATTERN (insn), 2),
1269 convert_from_eh_region_ranges ()
1274 collect_eh_region_array ();
1275 resolve_fixup_regions ();
1277 stack = xmalloc (sizeof (int) * (cfun->eh->last_region_number + 1));
1278 insns = get_insns ();
1279 convert_from_eh_region_ranges_1 (&insns, stack, 0);
1282 remove_fixup_regions ();
1286 find_exception_handler_labels ()
1288 rtx list = NULL_RTX;
1291 free_EXPR_LIST_list (&exception_handler_labels);
1293 if (cfun->eh->region_tree == NULL)
1296 for (i = cfun->eh->last_region_number; i > 0; --i)
1298 struct eh_region *region = cfun->eh->region_array[i];
1303 if (cfun->eh->built_landing_pads)
1304 lab = region->landing_pad;
1306 lab = region->label;
1309 list = alloc_EXPR_LIST (0, lab, list);
1312 /* For sjlj exceptions, need the return label to remain live until
1313 after landing pad generation. */
1314 if (USING_SJLJ_EXCEPTIONS && ! cfun->eh->built_landing_pads)
1315 list = alloc_EXPR_LIST (0, return_label, list);
1317 exception_handler_labels = list;
1321 static struct eh_region *
1322 duplicate_eh_region_1 (o, map)
1323 struct eh_region *o;
1324 struct inline_remap *map;
1327 = (struct eh_region *) xcalloc (1, sizeof (struct eh_region));
1329 n->region_number = o->region_number + cfun->eh->last_region_number;
1335 case ERT_MUST_NOT_THROW:
1339 if (o->u.try.continue_label)
1340 n->u.try.continue_label
1341 = get_label_from_map (map,
1342 CODE_LABEL_NUMBER (o->u.try.continue_label));
1346 n->u.catch.type = o->u.catch.type;
1349 case ERT_ALLOWED_EXCEPTIONS:
1350 n->u.allowed.type_list = o->u.allowed.type_list;
1354 n->u.throw.type = o->u.throw.type;
1361 n->label = get_label_from_map (map, CODE_LABEL_NUMBER (o->label));
1364 n->resume = map->insn_map[INSN_UID (o->resume)];
1365 if (n->resume == NULL)
1373 duplicate_eh_region_2 (o, n_array)
1374 struct eh_region *o;
1375 struct eh_region **n_array;
1377 struct eh_region *n = n_array[o->region_number];
1382 n->u.try.catch = n_array[o->u.try.catch->region_number];
1383 n->u.try.last_catch = n_array[o->u.try.last_catch->region_number];
1387 if (o->u.catch.next_catch)
1388 n->u.catch.next_catch = n_array[o->u.catch.next_catch->region_number];
1389 if (o->u.catch.prev_catch)
1390 n->u.catch.prev_catch = n_array[o->u.catch.prev_catch->region_number];
1398 n->outer = n_array[o->outer->region_number];
1400 n->inner = n_array[o->inner->region_number];
1402 n->next_peer = n_array[o->next_peer->region_number];
1406 duplicate_eh_regions (ifun, map)
1407 struct function *ifun;
1408 struct inline_remap *map;
1410 int ifun_last_region_number = ifun->eh->last_region_number;
1411 struct eh_region **n_array, *root, *cur;
1414 if (ifun_last_region_number == 0)
1417 n_array = xcalloc (ifun_last_region_number + 1, sizeof (*n_array));
1419 for (i = 1; i <= ifun_last_region_number; ++i)
1421 cur = ifun->eh->region_array[i];
1422 if (!cur || cur->region_number != i)
1424 n_array[i] = duplicate_eh_region_1 (cur, map);
1426 for (i = 1; i <= ifun_last_region_number; ++i)
1428 cur = ifun->eh->region_array[i];
1429 if (!cur || cur->region_number != i)
1431 duplicate_eh_region_2 (cur, n_array);
1434 root = n_array[ifun->eh->region_tree->region_number];
1435 cur = cfun->eh->cur_region;
1438 struct eh_region *p = cur->inner;
1441 while (p->next_peer)
1443 p->next_peer = root;
1448 for (i = 1; i <= ifun_last_region_number; ++i)
1449 if (n_array[i] && n_array[i]->outer == NULL)
1450 n_array[i]->outer = cur;
1454 struct eh_region *p = cfun->eh->region_tree;
1457 while (p->next_peer)
1459 p->next_peer = root;
1462 cfun->eh->region_tree = root;
1467 i = cfun->eh->last_region_number;
1468 cfun->eh->last_region_number = i + ifun_last_region_number;
1473 /* ??? Move from tree.c to tree.h. */
1474 #define TYPE_HASH(TYPE) ((HOST_WIDE_INT) (TYPE) & 0777777)
1477 t2r_eq (pentry, pdata)
1481 tree entry = (tree) pentry;
1482 tree data = (tree) pdata;
1484 return TREE_PURPOSE (entry) == data;
1491 tree entry = (tree) pentry;
1492 return TYPE_HASH (TREE_PURPOSE (entry));
1496 t2r_mark_1 (slot, data)
1498 PTR data ATTRIBUTE_UNUSED;
1500 tree contents = (tree) *slot;
1501 ggc_mark_tree (contents);
1509 htab_traverse (*(htab_t *)addr, t2r_mark_1, NULL);
1513 add_type_for_runtime (type)
1518 slot = (tree *) htab_find_slot_with_hash (type_to_runtime_map, type,
1519 TYPE_HASH (type), INSERT);
1522 tree runtime = (*lang_eh_runtime_type) (type);
1523 *slot = tree_cons (type, runtime, NULL_TREE);
1528 lookup_type_for_runtime (type)
1533 slot = (tree *) htab_find_slot_with_hash (type_to_runtime_map, type,
1534 TYPE_HASH (type), NO_INSERT);
1536 /* We should have always inserrted the data earlier. */
1537 return TREE_VALUE (*slot);
1541 /* Represent an entry in @TTypes for either catch actions
1542 or exception filter actions. */
1543 struct ttypes_filter
1549 /* Compare ENTRY (a ttypes_filter entry in the hash table) with DATA
1550 (a tree) for a @TTypes type node we are thinking about adding. */
1553 ttypes_filter_eq (pentry, pdata)
1557 const struct ttypes_filter *entry = (const struct ttypes_filter *) pentry;
1558 tree data = (tree) pdata;
1560 return entry->t == data;
1564 ttypes_filter_hash (pentry)
1567 const struct ttypes_filter *entry = (const struct ttypes_filter *) pentry;
1568 return TYPE_HASH (entry->t);
1571 /* Compare ENTRY with DATA (both struct ttypes_filter) for a @TTypes
1572 exception specification list we are thinking about adding. */
1573 /* ??? Currently we use the type lists in the order given. Someone
1574 should put these in some canonical order. */
1577 ehspec_filter_eq (pentry, pdata)
1581 const struct ttypes_filter *entry = (const struct ttypes_filter *) pentry;
1582 const struct ttypes_filter *data = (const struct ttypes_filter *) pdata;
1584 return type_list_equal (entry->t, data->t);
1587 /* Hash function for exception specification lists. */
1590 ehspec_filter_hash (pentry)
1593 const struct ttypes_filter *entry = (const struct ttypes_filter *) pentry;
1597 for (list = entry->t; list ; list = TREE_CHAIN (list))
1598 h = (h << 5) + (h >> 27) + TYPE_HASH (TREE_VALUE (list));
1602 /* Add TYPE to cfun->eh->ttype_data, using TYPES_HASH to speed
1603 up the search. Return the filter value to be used. */
1606 add_ttypes_entry (ttypes_hash, type)
1610 struct ttypes_filter **slot, *n;
1612 slot = (struct ttypes_filter **)
1613 htab_find_slot_with_hash (ttypes_hash, type, TYPE_HASH (type), INSERT);
1615 if ((n = *slot) == NULL)
1617 /* Filter value is a 1 based table index. */
1619 n = (struct ttypes_filter *) xmalloc (sizeof (*n));
1621 n->filter = VARRAY_ACTIVE_SIZE (cfun->eh->ttype_data) + 1;
1624 VARRAY_PUSH_TREE (cfun->eh->ttype_data, type);
1630 /* Add LIST to cfun->eh->ehspec_data, using EHSPEC_HASH and TYPES_HASH
1631 to speed up the search. Return the filter value to be used. */
1634 add_ehspec_entry (ehspec_hash, ttypes_hash, list)
1639 struct ttypes_filter **slot, *n;
1640 struct ttypes_filter dummy;
1643 slot = (struct ttypes_filter **)
1644 htab_find_slot (ehspec_hash, &dummy, INSERT);
1646 if ((n = *slot) == NULL)
1648 /* Filter value is a -1 based byte index into a uleb128 buffer. */
1650 n = (struct ttypes_filter *) xmalloc (sizeof (*n));
1652 n->filter = -(VARRAY_ACTIVE_SIZE (cfun->eh->ehspec_data) + 1);
1655 /* Look up each type in the list and encode its filter
1656 value as a uleb128. Terminate the list with 0. */
1657 for (; list ; list = TREE_CHAIN (list))
1658 push_uleb128 (&cfun->eh->ehspec_data,
1659 add_ttypes_entry (ttypes_hash, TREE_VALUE (list)));
1660 VARRAY_PUSH_UCHAR (cfun->eh->ehspec_data, 0);
1666 /* Generate the action filter values to be used for CATCH and
1667 ALLOWED_EXCEPTIONS regions. When using dwarf2 exception regions,
1668 we use lots of landing pads, and so every type or list can share
1669 the same filter value, which saves table space. */
1672 assign_filter_values ()
1675 htab_t ttypes, ehspec;
1677 VARRAY_TREE_INIT (cfun->eh->ttype_data, 16, "ttype_data");
1678 VARRAY_UCHAR_INIT (cfun->eh->ehspec_data, 64, "ehspec_data");
1680 ttypes = htab_create (31, ttypes_filter_hash, ttypes_filter_eq, free);
1681 ehspec = htab_create (31, ehspec_filter_hash, ehspec_filter_eq, free);
1683 for (i = cfun->eh->last_region_number; i > 0; --i)
1685 struct eh_region *r = cfun->eh->region_array[i];
1687 /* Mind we don't process a region more than once. */
1688 if (!r || r->region_number != i)
1694 r->u.catch.filter = add_ttypes_entry (ttypes, r->u.catch.type);
1697 case ERT_ALLOWED_EXCEPTIONS:
1699 = add_ehspec_entry (ehspec, ttypes, r->u.allowed.type_list);
1707 htab_delete (ttypes);
1708 htab_delete (ehspec);
1712 build_post_landing_pads ()
1716 for (i = cfun->eh->last_region_number; i > 0; --i)
1718 struct eh_region *region = cfun->eh->region_array[i];
1721 /* Mind we don't process a region more than once. */
1722 if (!region || region->region_number != i)
1725 switch (region->type)
1728 /* ??? Collect the set of all non-overlapping catch handlers
1729 all the way up the chain until blocked by a cleanup. */
1730 /* ??? Outer try regions can share landing pads with inner
1731 try regions if the types are completely non-overlapping,
1732 and there are no interveaning cleanups. */
1734 region->post_landing_pad = gen_label_rtx ();
1738 emit_label (region->post_landing_pad);
1740 /* ??? It is mighty inconvenient to call back into the
1741 switch statement generation code in expand_end_case.
1742 Rapid prototyping sez a sequence of ifs. */
1744 struct eh_region *c;
1745 for (c = region->u.try.catch; c ; c = c->u.catch.next_catch)
1747 /* ??? _Unwind_ForcedUnwind wants no match here. */
1748 if (c->u.catch.type == NULL)
1749 emit_jump (c->label);
1751 emit_cmp_and_jump_insns (cfun->eh->filter,
1752 GEN_INT (c->u.catch.filter),
1753 EQ, NULL_RTX, word_mode,
1758 /* We delay the generation of the _Unwind_Resume until we generate
1759 landing pads. We emit a marker here so as to get good control
1760 flow data in the meantime. */
1762 = emit_jump_insn (gen_rtx_RESX (VOIDmode, region->region_number));
1768 emit_insns_before (seq, region->u.try.catch->label);
1771 case ERT_ALLOWED_EXCEPTIONS:
1772 region->post_landing_pad = gen_label_rtx ();
1776 emit_label (region->post_landing_pad);
1778 emit_cmp_and_jump_insns (cfun->eh->filter,
1779 GEN_INT (region->u.allowed.filter),
1780 EQ, NULL_RTX, word_mode, 0, 0,
1783 /* We delay the generation of the _Unwind_Resume until we generate
1784 landing pads. We emit a marker here so as to get good control
1785 flow data in the meantime. */
1787 = emit_jump_insn (gen_rtx_RESX (VOIDmode, region->region_number));
1793 emit_insns_before (seq, region->label);
1797 case ERT_MUST_NOT_THROW:
1798 region->post_landing_pad = region->label;
1803 /* Nothing to do. */
1812 /* Replace RESX patterns with jumps to the next handler if any, or calls to
1813 _Unwind_Resume otherwise. */
1816 connect_post_landing_pads ()
1820 for (i = cfun->eh->last_region_number; i > 0; --i)
1822 struct eh_region *region = cfun->eh->region_array[i];
1823 struct eh_region *outer;
1826 /* Mind we don't process a region more than once. */
1827 if (!region || region->region_number != i)
1830 /* If there is no RESX, or it has been deleted by flow, there's
1831 nothing to fix up. */
1832 if (! region->resume || INSN_DELETED_P (region->resume))
1835 /* Search for another landing pad in this function. */
1836 for (outer = region->outer; outer ; outer = outer->outer)
1837 if (outer->post_landing_pad)
1843 emit_jump (outer->post_landing_pad);
1845 emit_library_call (unwind_resume_libfunc, LCT_THROW,
1846 VOIDmode, 1, cfun->eh->exc_ptr, Pmode);
1850 emit_insns_before (seq, region->resume);
1851 flow_delete_insn (region->resume);
1857 dw2_build_landing_pads ()
1862 for (i = cfun->eh->last_region_number; i > 0; --i)
1864 struct eh_region *region = cfun->eh->region_array[i];
1867 /* Mind we don't process a region more than once. */
1868 if (!region || region->region_number != i)
1871 if (region->type != ERT_CLEANUP
1872 && region->type != ERT_TRY
1873 && region->type != ERT_ALLOWED_EXCEPTIONS)
1878 region->landing_pad = gen_label_rtx ();
1879 emit_label (region->landing_pad);
1881 #ifdef HAVE_exception_receiver
1882 if (HAVE_exception_receiver)
1883 emit_insn (gen_exception_receiver ());
1886 #ifdef HAVE_nonlocal_goto_receiver
1887 if (HAVE_nonlocal_goto_receiver)
1888 emit_insn (gen_nonlocal_goto_receiver ());
1893 /* If the eh_return data registers are call-saved, then we
1894 won't have considered them clobbered from the call that
1895 threw. Kill them now. */
1898 unsigned r = EH_RETURN_DATA_REGNO (j);
1899 if (r == INVALID_REGNUM)
1901 if (! call_used_regs[r])
1902 emit_insn (gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (Pmode, r)));
1905 emit_move_insn (cfun->eh->exc_ptr,
1906 gen_rtx_REG (Pmode, EH_RETURN_DATA_REGNO (0)));
1907 emit_move_insn (cfun->eh->filter,
1908 gen_rtx_REG (word_mode, EH_RETURN_DATA_REGNO (1)));
1913 emit_insns_before (seq, region->post_landing_pad);
1920 int directly_reachable;
1923 int call_site_index;
1927 sjlj_find_directly_reachable_regions (lp_info)
1928 struct sjlj_lp_info *lp_info;
1931 bool found_one = false;
1933 for (insn = get_insns (); insn ; insn = NEXT_INSN (insn))
1935 struct eh_region *region;
1939 if (! INSN_P (insn))
1942 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1943 if (!note || INTVAL (XEXP (note, 0)) <= 0)
1946 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
1948 type_thrown = NULL_TREE;
1949 if (region->type == ERT_THROW)
1951 type_thrown = region->u.throw.type;
1952 region = region->outer;
1955 /* Find the first containing region that might handle the exception.
1956 That's the landing pad to which we will transfer control. */
1957 for (; region; region = region->outer)
1958 if (reachable_next_level (region, type_thrown, 0) != RNL_NOT_CAUGHT)
1963 lp_info[region->region_number].directly_reachable = 1;
1972 sjlj_assign_call_site_values (dispatch_label, lp_info)
1974 struct sjlj_lp_info *lp_info;
1979 /* First task: build the action table. */
1981 VARRAY_UCHAR_INIT (cfun->eh->action_record_data, 64, "action_record_data");
1982 ar_hash = htab_create (31, action_record_hash, action_record_eq, free);
1984 for (i = cfun->eh->last_region_number; i > 0; --i)
1985 if (lp_info[i].directly_reachable)
1987 struct eh_region *r = cfun->eh->region_array[i];
1988 r->landing_pad = dispatch_label;
1989 lp_info[i].action_index = collect_one_action_chain (ar_hash, r);
1990 if (lp_info[i].action_index != -1)
1991 cfun->uses_eh_lsda = 1;
1994 htab_delete (ar_hash);
1996 /* Next: assign dispatch values. In dwarf2 terms, this would be the
1997 landing pad label for the region. For sjlj though, there is one
1998 common landing pad from which we dispatch to the post-landing pads.
2000 A region receives a dispatch index if it is directly reachable
2001 and requires in-function processing. Regions that share post-landing
2002 pads may share dispatch indicies. */
2003 /* ??? Post-landing pad sharing doesn't actually happen at the moment
2004 (see build_post_landing_pads) so we don't bother checking for it. */
2007 for (i = cfun->eh->last_region_number; i > 0; --i)
2008 if (lp_info[i].directly_reachable
2009 && lp_info[i].action_index >= 0)
2010 lp_info[i].dispatch_index = index++;
2012 /* Finally: assign call-site values. If dwarf2 terms, this would be
2013 the region number assigned by convert_to_eh_region_ranges, but
2014 handles no-action and must-not-throw differently. */
2017 for (i = cfun->eh->last_region_number; i > 0; --i)
2018 if (lp_info[i].directly_reachable)
2020 int action = lp_info[i].action_index;
2022 /* Map must-not-throw to otherwise unused call-site index 0. */
2025 /* Map no-action to otherwise unused call-site index -1. */
2026 else if (action == -1)
2028 /* Otherwise, look it up in the table. */
2030 index = add_call_site (GEN_INT (lp_info[i].dispatch_index), action);
2032 lp_info[i].call_site_index = index;
2037 sjlj_mark_call_sites (lp_info)
2038 struct sjlj_lp_info *lp_info;
2040 int last_call_site = -2;
2043 mem = adjust_address (cfun->eh->sjlj_fc, TYPE_MODE (integer_type_node),
2044 sjlj_fc_call_site_ofs);
2046 for (insn = get_insns (); insn ; insn = NEXT_INSN (insn))
2048 struct eh_region *region;
2050 rtx note, before, p;
2052 /* Reset value tracking at extended basic block boundaries. */
2053 if (GET_CODE (insn) == CODE_LABEL)
2054 last_call_site = -2;
2056 if (! INSN_P (insn))
2059 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
2062 /* Calls (and trapping insns) without notes are outside any
2063 exception handling region in this function. Mark them as
2065 if (GET_CODE (insn) == CALL_INSN
2066 || (flag_non_call_exceptions
2067 && may_trap_p (PATTERN (insn))))
2068 this_call_site = -1;
2074 /* Calls that are known to not throw need not be marked. */
2075 if (INTVAL (XEXP (note, 0)) <= 0)
2078 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
2079 this_call_site = lp_info[region->region_number].call_site_index;
2082 if (this_call_site == last_call_site)
2085 /* Don't separate a call from it's argument loads. */
2087 if (GET_CODE (insn) == CALL_INSN)
2088 before = find_first_parameter_load (insn, NULL_RTX);
2091 emit_move_insn (mem, GEN_INT (this_call_site));
2095 emit_insns_before (p, before);
2096 last_call_site = this_call_site;
2100 /* Construct the SjLj_Function_Context. */
2103 sjlj_emit_function_enter (dispatch_label)
2106 rtx fn_begin, fc, mem, seq;
2108 fc = cfun->eh->sjlj_fc;
2112 /* We're storing this libcall's address into memory instead of
2113 calling it directly. Thus, we must call assemble_external_libcall
2114 here, as we can not depend on emit_library_call to do it for us. */
2115 assemble_external_libcall (eh_personality_libfunc);
2116 mem = adjust_address (fc, Pmode, sjlj_fc_personality_ofs);
2117 emit_move_insn (mem, eh_personality_libfunc);
2119 mem = adjust_address (fc, Pmode, sjlj_fc_lsda_ofs);
2120 if (cfun->uses_eh_lsda)
2123 ASM_GENERATE_INTERNAL_LABEL (buf, "LLSDA", sjlj_funcdef_number);
2124 emit_move_insn (mem, gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (buf)));
2127 emit_move_insn (mem, const0_rtx);
2129 #ifdef DONT_USE_BUILTIN_SETJMP
2132 x = emit_library_call_value (setjmp_libfunc, NULL_RTX, LCT_NORMAL,
2133 TYPE_MODE (integer_type_node), 1,
2134 plus_constant (XEXP (fc, 0),
2135 sjlj_fc_jbuf_ofs), Pmode);
2137 note = emit_note (NULL, NOTE_INSN_EXPECTED_VALUE);
2138 NOTE_EXPECTED_VALUE (note) = gen_rtx_EQ (VOIDmode, x, const0_rtx);
2140 emit_cmp_and_jump_insns (x, const0_rtx, NE, 0,
2141 TYPE_MODE (integer_type_node), 0, 0,
2145 expand_builtin_setjmp_setup (plus_constant (XEXP (fc, 0), sjlj_fc_jbuf_ofs),
2149 emit_library_call (unwind_sjlj_register_libfunc, LCT_NORMAL, VOIDmode,
2150 1, XEXP (fc, 0), Pmode);
2155 /* ??? Instead of doing this at the beginning of the function,
2156 do this in a block that is at loop level 0 and dominates all
2157 can_throw_internal instructions. */
2159 for (fn_begin = get_insns (); ; fn_begin = NEXT_INSN (fn_begin))
2160 if (GET_CODE (fn_begin) == NOTE
2161 && NOTE_LINE_NUMBER (fn_begin) == NOTE_INSN_FUNCTION_BEG)
2163 emit_insns_after (seq, fn_begin);
2166 /* Call back from expand_function_end to know where we should put
2167 the call to unwind_sjlj_unregister_libfunc if needed. */
2170 sjlj_emit_function_exit_after (after)
2173 cfun->eh->sjlj_exit_after = after;
2177 sjlj_emit_function_exit ()
2183 emit_library_call (unwind_sjlj_unregister_libfunc, LCT_NORMAL, VOIDmode,
2184 1, XEXP (cfun->eh->sjlj_fc, 0), Pmode);
2189 /* ??? Really this can be done in any block at loop level 0 that
2190 post-dominates all can_throw_internal instructions. This is
2191 the last possible moment. */
2193 emit_insns_after (seq, cfun->eh->sjlj_exit_after);
2197 sjlj_emit_dispatch_table (dispatch_label, lp_info)
2199 struct sjlj_lp_info *lp_info;
2201 int i, first_reachable;
2202 rtx mem, dispatch, seq, fc;
2204 fc = cfun->eh->sjlj_fc;
2208 emit_label (dispatch_label);
2210 #ifndef DONT_USE_BUILTIN_SETJMP
2211 expand_builtin_setjmp_receiver (dispatch_label);
2214 /* Load up dispatch index, exc_ptr and filter values from the
2215 function context. */
2216 mem = adjust_address (fc, TYPE_MODE (integer_type_node),
2217 sjlj_fc_call_site_ofs);
2218 dispatch = copy_to_reg (mem);
2220 mem = adjust_address (fc, word_mode, sjlj_fc_data_ofs);
2221 if (word_mode != Pmode)
2223 #ifdef POINTERS_EXTEND_UNSIGNED
2224 mem = convert_memory_address (Pmode, mem);
2226 mem = convert_to_mode (Pmode, mem, 0);
2229 emit_move_insn (cfun->eh->exc_ptr, mem);
2231 mem = adjust_address (fc, word_mode, sjlj_fc_data_ofs + UNITS_PER_WORD);
2232 emit_move_insn (cfun->eh->filter, mem);
2234 /* Jump to one of the directly reachable regions. */
2235 /* ??? This really ought to be using a switch statement. */
2237 first_reachable = 0;
2238 for (i = cfun->eh->last_region_number; i > 0; --i)
2240 if (! lp_info[i].directly_reachable
2241 || lp_info[i].action_index < 0)
2244 if (! first_reachable)
2246 first_reachable = i;
2250 emit_cmp_and_jump_insns (dispatch,
2251 GEN_INT (lp_info[i].dispatch_index), EQ,
2252 NULL_RTX, TYPE_MODE (integer_type_node), 0, 0,
2253 cfun->eh->region_array[i]->post_landing_pad);
2259 emit_insns_before (seq, (cfun->eh->region_array[first_reachable]
2260 ->post_landing_pad));
2264 sjlj_build_landing_pads ()
2266 struct sjlj_lp_info *lp_info;
2268 lp_info = (struct sjlj_lp_info *) xcalloc (cfun->eh->last_region_number + 1,
2269 sizeof (struct sjlj_lp_info));
2271 if (sjlj_find_directly_reachable_regions (lp_info))
2273 rtx dispatch_label = gen_label_rtx ();
2276 = assign_stack_local (TYPE_MODE (sjlj_fc_type_node),
2277 int_size_in_bytes (sjlj_fc_type_node),
2278 TYPE_ALIGN (sjlj_fc_type_node));
2280 sjlj_assign_call_site_values (dispatch_label, lp_info);
2281 sjlj_mark_call_sites (lp_info);
2283 sjlj_emit_function_enter (dispatch_label);
2284 sjlj_emit_dispatch_table (dispatch_label, lp_info);
2285 sjlj_emit_function_exit ();
2292 finish_eh_generation ()
2294 /* Nothing to do if no regions created. */
2295 if (cfun->eh->region_tree == NULL)
2298 /* The object here is to provide find_basic_blocks with detailed
2299 information (via reachable_handlers) on how exception control
2300 flows within the function. In this first pass, we can include
2301 type information garnered from ERT_THROW and ERT_ALLOWED_EXCEPTIONS
2302 regions, and hope that it will be useful in deleting unreachable
2303 handlers. Subsequently, we will generate landing pads which will
2304 connect many of the handlers, and then type information will not
2305 be effective. Still, this is a win over previous implementations. */
2307 rebuild_jump_labels (get_insns ());
2308 find_basic_blocks (get_insns (), max_reg_num (), 0);
2309 cleanup_cfg (CLEANUP_PRE_LOOP);
2311 /* These registers are used by the landing pads. Make sure they
2312 have been generated. */
2313 get_exception_pointer (cfun);
2314 get_exception_filter (cfun);
2316 /* Construct the landing pads. */
2318 assign_filter_values ();
2319 build_post_landing_pads ();
2320 connect_post_landing_pads ();
2321 if (USING_SJLJ_EXCEPTIONS)
2322 sjlj_build_landing_pads ();
2324 dw2_build_landing_pads ();
2326 cfun->eh->built_landing_pads = 1;
2328 /* We've totally changed the CFG. Start over. */
2329 find_exception_handler_labels ();
2330 rebuild_jump_labels (get_insns ());
2331 find_basic_blocks (get_insns (), max_reg_num (), 0);
2332 cleanup_cfg (CLEANUP_PRE_LOOP);
2335 /* This section handles removing dead code for flow. */
2337 /* Remove LABEL from the exception_handler_labels list. */
2340 remove_exception_handler_label (label)
2345 for (pl = &exception_handler_labels, l = *pl;
2346 XEXP (l, 0) != label;
2347 pl = &XEXP (l, 1), l = *pl)
2351 free_EXPR_LIST_node (l);
2354 /* Splice REGION from the region tree etc. */
2357 remove_eh_handler (region)
2358 struct eh_region *region;
2360 struct eh_region **pp, *p;
2364 /* For the benefit of efficiently handling REG_EH_REGION notes,
2365 replace this region in the region array with its containing
2366 region. Note that previous region deletions may result in
2367 multiple copies of this region in the array, so we have to
2368 search the whole thing. */
2369 for (i = cfun->eh->last_region_number; i > 0; --i)
2370 if (cfun->eh->region_array[i] == region)
2371 cfun->eh->region_array[i] = region->outer;
2373 if (cfun->eh->built_landing_pads)
2374 lab = region->landing_pad;
2376 lab = region->label;
2378 remove_exception_handler_label (lab);
2381 pp = ®ion->outer->inner;
2383 pp = &cfun->eh->region_tree;
2384 for (p = *pp; p != region; pp = &p->next_peer, p = *pp)
2389 for (p = region->inner; p->next_peer ; p = p->next_peer)
2390 p->outer = region->outer;
2391 p->next_peer = region->next_peer;
2392 p->outer = region->outer;
2393 *pp = region->inner;
2396 *pp = region->next_peer;
2398 if (region->type == ERT_CATCH)
2400 struct eh_region *try, *next, *prev;
2402 for (try = region->next_peer;
2403 try->type == ERT_CATCH;
2404 try = try->next_peer)
2406 if (try->type != ERT_TRY)
2409 next = region->u.catch.next_catch;
2410 prev = region->u.catch.prev_catch;
2413 next->u.catch.prev_catch = prev;
2415 try->u.try.last_catch = prev;
2417 prev->u.catch.next_catch = next;
2420 try->u.try.catch = next;
2422 remove_eh_handler (try);
2429 /* LABEL heads a basic block that is about to be deleted. If this
2430 label corresponds to an exception region, we may be able to
2431 delete the region. */
2434 maybe_remove_eh_handler (label)
2439 /* ??? After generating landing pads, it's not so simple to determine
2440 if the region data is completely unused. One must examine the
2441 landing pad and the post landing pad, and whether an inner try block
2442 is referencing the catch handlers directly. */
2443 if (cfun->eh->built_landing_pads)
2446 for (i = cfun->eh->last_region_number; i > 0; --i)
2448 struct eh_region *region = cfun->eh->region_array[i];
2449 if (region && region->label == label)
2451 /* Flow will want to remove MUST_NOT_THROW regions as unreachable
2452 because there is no path to the fallback call to terminate.
2453 But the region continues to affect call-site data until there
2454 are no more contained calls, which we don't see here. */
2455 if (region->type == ERT_MUST_NOT_THROW)
2457 remove_exception_handler_label (region->label);
2458 region->label = NULL_RTX;
2461 remove_eh_handler (region);
2468 /* This section describes CFG exception edges for flow. */
2470 /* For communicating between calls to reachable_next_level. */
2471 struct reachable_info
2478 /* A subroutine of reachable_next_level. Return true if TYPE, or a
2479 base class of TYPE, is in HANDLED. */
2482 check_handled (handled, type)
2487 /* We can check for exact matches without front-end help. */
2488 if (! lang_eh_type_covers)
2490 for (t = handled; t ; t = TREE_CHAIN (t))
2491 if (TREE_VALUE (t) == type)
2496 for (t = handled; t ; t = TREE_CHAIN (t))
2497 if ((*lang_eh_type_covers) (TREE_VALUE (t), type))
2504 /* A subroutine of reachable_next_level. If we are collecting a list
2505 of handlers, add one. After landing pad generation, reference
2506 it instead of the handlers themselves. Further, the handlers are
2507 all wired together, so by referencing one, we've got them all.
2508 Before landing pad generation we reference each handler individually.
2510 LP_REGION contains the landing pad; REGION is the handler. */
2513 add_reachable_handler (info, lp_region, region)
2514 struct reachable_info *info;
2515 struct eh_region *lp_region;
2516 struct eh_region *region;
2521 if (cfun->eh->built_landing_pads)
2523 if (! info->handlers)
2524 info->handlers = alloc_INSN_LIST (lp_region->landing_pad, NULL_RTX);
2527 info->handlers = alloc_INSN_LIST (region->label, info->handlers);
2530 /* Process one level of exception regions for reachability.
2531 If TYPE_THROWN is non-null, then it is the *exact* type being
2532 propagated. If INFO is non-null, then collect handler labels
2533 and caught/allowed type information between invocations. */
2535 static enum reachable_code
2536 reachable_next_level (region, type_thrown, info)
2537 struct eh_region *region;
2539 struct reachable_info *info;
2541 switch (region->type)
2544 /* Before landing-pad generation, we model control flow
2545 directly to the individual handlers. In this way we can
2546 see that catch handler types may shadow one another. */
2547 add_reachable_handler (info, region, region);
2548 return RNL_MAYBE_CAUGHT;
2552 struct eh_region *c;
2553 enum reachable_code ret = RNL_NOT_CAUGHT;
2555 for (c = region->u.try.catch; c ; c = c->u.catch.next_catch)
2557 /* A catch-all handler ends the search. */
2558 /* ??? _Unwind_ForcedUnwind will want outer cleanups
2559 to be run as well. */
2560 if (c->u.catch.type == NULL)
2562 add_reachable_handler (info, region, c);
2568 /* If we have a type match, end the search. */
2569 if (c->u.catch.type == type_thrown
2570 || (lang_eh_type_covers
2571 && (*lang_eh_type_covers) (c->u.catch.type,
2574 add_reachable_handler (info, region, c);
2578 /* If we have definitive information of a match failure,
2579 the catch won't trigger. */
2580 if (lang_eh_type_covers)
2581 return RNL_NOT_CAUGHT;
2585 ret = RNL_MAYBE_CAUGHT;
2587 /* A type must not have been previously caught. */
2588 else if (! check_handled (info->types_caught, c->u.catch.type))
2590 add_reachable_handler (info, region, c);
2591 info->types_caught = tree_cons (NULL, c->u.catch.type,
2592 info->types_caught);
2594 /* ??? If the catch type is a base class of every allowed
2595 type, then we know we can stop the search. */
2596 ret = RNL_MAYBE_CAUGHT;
2603 case ERT_ALLOWED_EXCEPTIONS:
2604 /* An empty list of types definitely ends the search. */
2605 if (region->u.allowed.type_list == NULL_TREE)
2607 add_reachable_handler (info, region, region);
2611 /* Collect a list of lists of allowed types for use in detecting
2612 when a catch may be transformed into a catch-all. */
2614 info->types_allowed = tree_cons (NULL_TREE,
2615 region->u.allowed.type_list,
2616 info->types_allowed);
2618 /* If we have definitive information about the type heirarchy,
2619 then we can tell if the thrown type will pass through the
2621 if (type_thrown && lang_eh_type_covers)
2623 if (check_handled (region->u.allowed.type_list, type_thrown))
2624 return RNL_NOT_CAUGHT;
2627 add_reachable_handler (info, region, region);
2632 add_reachable_handler (info, region, region);
2633 return RNL_MAYBE_CAUGHT;
2636 /* Catch regions are handled by their controling try region. */
2637 return RNL_NOT_CAUGHT;
2639 case ERT_MUST_NOT_THROW:
2640 /* Here we end our search, since no exceptions may propagate.
2641 If we've touched down at some landing pad previous, then the
2642 explicit function call we generated may be used. Otherwise
2643 the call is made by the runtime. */
2644 if (info && info->handlers)
2646 add_reachable_handler (info, region, region);
2654 /* Shouldn't see these here. */
2661 /* Retrieve a list of labels of exception handlers which can be
2662 reached by a given insn. */
2665 reachable_handlers (insn)
2668 struct reachable_info info;
2669 struct eh_region *region;
2673 if (GET_CODE (insn) == JUMP_INSN
2674 && GET_CODE (PATTERN (insn)) == RESX)
2675 region_number = XINT (PATTERN (insn), 0);
2678 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
2679 if (!note || INTVAL (XEXP (note, 0)) <= 0)
2681 region_number = INTVAL (XEXP (note, 0));
2684 memset (&info, 0, sizeof (info));
2686 region = cfun->eh->region_array[region_number];
2688 type_thrown = NULL_TREE;
2689 if (GET_CODE (insn) == JUMP_INSN
2690 && GET_CODE (PATTERN (insn)) == RESX)
2692 /* A RESX leaves a region instead of entering it. Thus the
2693 region itself may have been deleted out from under us. */
2696 region = region->outer;
2698 else if (region->type == ERT_THROW)
2700 type_thrown = region->u.throw.type;
2701 region = region->outer;
2704 for (; region; region = region->outer)
2705 if (reachable_next_level (region, type_thrown, &info) >= RNL_CAUGHT)
2708 return info.handlers;
2711 /* Determine if the given INSN can throw an exception that is caught
2712 within the function. */
2715 can_throw_internal (insn)
2718 struct eh_region *region;
2722 if (! INSN_P (insn))
2725 if (GET_CODE (insn) == INSN
2726 && GET_CODE (PATTERN (insn)) == SEQUENCE)
2727 insn = XVECEXP (PATTERN (insn), 0, 0);
2729 if (GET_CODE (insn) == CALL_INSN
2730 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
2733 for (i = 0; i < 3; ++i)
2735 rtx sub = XEXP (PATTERN (insn), i);
2736 for (; sub ; sub = NEXT_INSN (sub))
2737 if (can_throw_internal (sub))
2743 /* Every insn that might throw has an EH_REGION note. */
2744 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
2745 if (!note || INTVAL (XEXP (note, 0)) <= 0)
2748 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
2750 type_thrown = NULL_TREE;
2751 if (region->type == ERT_THROW)
2753 type_thrown = region->u.throw.type;
2754 region = region->outer;
2757 /* If this exception is ignored by each and every containing region,
2758 then control passes straight out. The runtime may handle some
2759 regions, which also do not require processing internally. */
2760 for (; region; region = region->outer)
2762 enum reachable_code how = reachable_next_level (region, type_thrown, 0);
2763 if (how == RNL_BLOCKED)
2765 if (how != RNL_NOT_CAUGHT)
2772 /* Determine if the given INSN can throw an exception that is
2773 visible outside the function. */
2776 can_throw_external (insn)
2779 struct eh_region *region;
2783 if (! INSN_P (insn))
2786 if (GET_CODE (insn) == INSN
2787 && GET_CODE (PATTERN (insn)) == SEQUENCE)
2788 insn = XVECEXP (PATTERN (insn), 0, 0);
2790 if (GET_CODE (insn) == CALL_INSN
2791 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
2794 for (i = 0; i < 3; ++i)
2796 rtx sub = XEXP (PATTERN (insn), i);
2797 for (; sub ; sub = NEXT_INSN (sub))
2798 if (can_throw_external (sub))
2804 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
2807 /* Calls (and trapping insns) without notes are outside any
2808 exception handling region in this function. We have to
2809 assume it might throw. Given that the front end and middle
2810 ends mark known NOTHROW functions, this isn't so wildly
2812 return (GET_CODE (insn) == CALL_INSN
2813 || (flag_non_call_exceptions
2814 && may_trap_p (PATTERN (insn))));
2816 if (INTVAL (XEXP (note, 0)) <= 0)
2819 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
2821 type_thrown = NULL_TREE;
2822 if (region->type == ERT_THROW)
2824 type_thrown = region->u.throw.type;
2825 region = region->outer;
2828 /* If the exception is caught or blocked by any containing region,
2829 then it is not seen by any calling function. */
2830 for (; region ; region = region->outer)
2831 if (reachable_next_level (region, type_thrown, NULL) >= RNL_CAUGHT)
2837 /* True if nothing in this function can throw outside this function. */
2840 nothrow_function_p ()
2844 if (! flag_exceptions)
2847 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2848 if (can_throw_external (insn))
2850 for (insn = current_function_epilogue_delay_list; insn;
2851 insn = XEXP (insn, 1))
2852 if (can_throw_external (insn))
2859 /* Various hooks for unwind library. */
2861 /* Do any necessary initialization to access arbitrary stack frames.
2862 On the SPARC, this means flushing the register windows. */
2865 expand_builtin_unwind_init ()
2867 /* Set this so all the registers get saved in our frame; we need to be
2868 able to copy the saved values for any registers from frames we unwind. */
2869 current_function_has_nonlocal_label = 1;
2871 #ifdef SETUP_FRAME_ADDRESSES
2872 SETUP_FRAME_ADDRESSES ();
2877 expand_builtin_eh_return_data_regno (arglist)
2880 tree which = TREE_VALUE (arglist);
2881 unsigned HOST_WIDE_INT iwhich;
2883 if (TREE_CODE (which) != INTEGER_CST)
2885 error ("argument of `__builtin_eh_return_regno' must be constant");
2889 iwhich = tree_low_cst (which, 1);
2890 iwhich = EH_RETURN_DATA_REGNO (iwhich);
2891 if (iwhich == INVALID_REGNUM)
2894 #ifdef DWARF_FRAME_REGNUM
2895 iwhich = DWARF_FRAME_REGNUM (iwhich);
2897 iwhich = DBX_REGISTER_NUMBER (iwhich);
2900 return GEN_INT (iwhich);
2903 /* Given a value extracted from the return address register or stack slot,
2904 return the actual address encoded in that value. */
2907 expand_builtin_extract_return_addr (addr_tree)
2910 rtx addr = expand_expr (addr_tree, NULL_RTX, Pmode, 0);
2912 /* First mask out any unwanted bits. */
2913 #ifdef MASK_RETURN_ADDR
2914 expand_and (addr, MASK_RETURN_ADDR, addr);
2917 /* Then adjust to find the real return address. */
2918 #if defined (RETURN_ADDR_OFFSET)
2919 addr = plus_constant (addr, RETURN_ADDR_OFFSET);
2925 /* Given an actual address in addr_tree, do any necessary encoding
2926 and return the value to be stored in the return address register or
2927 stack slot so the epilogue will return to that address. */
2930 expand_builtin_frob_return_addr (addr_tree)
2933 rtx addr = expand_expr (addr_tree, NULL_RTX, Pmode, 0);
2935 #ifdef POINTERS_EXTEND_UNSIGNED
2936 addr = convert_memory_address (Pmode, addr);
2939 #ifdef RETURN_ADDR_OFFSET
2940 addr = force_reg (Pmode, addr);
2941 addr = plus_constant (addr, -RETURN_ADDR_OFFSET);
2947 /* Set up the epilogue with the magic bits we'll need to return to the
2948 exception handler. */
2951 expand_builtin_eh_return (stackadj_tree, handler_tree)
2952 tree stackadj_tree, handler_tree;
2954 rtx stackadj, handler;
2956 stackadj = expand_expr (stackadj_tree, cfun->eh->ehr_stackadj, VOIDmode, 0);
2957 handler = expand_expr (handler_tree, cfun->eh->ehr_handler, VOIDmode, 0);
2959 #ifdef POINTERS_EXTEND_UNSIGNED
2960 stackadj = convert_memory_address (Pmode, stackadj);
2961 handler = convert_memory_address (Pmode, handler);
2964 if (! cfun->eh->ehr_label)
2966 cfun->eh->ehr_stackadj = copy_to_reg (stackadj);
2967 cfun->eh->ehr_handler = copy_to_reg (handler);
2968 cfun->eh->ehr_label = gen_label_rtx ();
2972 if (stackadj != cfun->eh->ehr_stackadj)
2973 emit_move_insn (cfun->eh->ehr_stackadj, stackadj);
2974 if (handler != cfun->eh->ehr_handler)
2975 emit_move_insn (cfun->eh->ehr_handler, handler);
2978 emit_jump (cfun->eh->ehr_label);
2984 rtx sa, ra, around_label;
2986 if (! cfun->eh->ehr_label)
2989 sa = EH_RETURN_STACKADJ_RTX;
2992 error ("__builtin_eh_return not supported on this target");
2996 current_function_calls_eh_return = 1;
2998 around_label = gen_label_rtx ();
2999 emit_move_insn (sa, const0_rtx);
3000 emit_jump (around_label);
3002 emit_label (cfun->eh->ehr_label);
3003 clobber_return_register ();
3005 #ifdef HAVE_eh_return
3007 emit_insn (gen_eh_return (cfun->eh->ehr_stackadj, cfun->eh->ehr_handler));
3011 ra = EH_RETURN_HANDLER_RTX;
3014 error ("__builtin_eh_return not supported on this target");
3015 ra = gen_reg_rtx (Pmode);
3018 emit_move_insn (sa, cfun->eh->ehr_stackadj);
3019 emit_move_insn (ra, cfun->eh->ehr_handler);
3022 emit_label (around_label);
3025 /* In the following functions, we represent entries in the action table
3026 as 1-based indicies. Special cases are:
3028 0: null action record, non-null landing pad; implies cleanups
3029 -1: null action record, null landing pad; implies no action
3030 -2: no call-site entry; implies must_not_throw
3031 -3: we have yet to process outer regions
3033 Further, no special cases apply to the "next" field of the record.
3034 For next, 0 means end of list. */
3036 struct action_record
3044 action_record_eq (pentry, pdata)
3048 const struct action_record *entry = (const struct action_record *) pentry;
3049 const struct action_record *data = (const struct action_record *) pdata;
3050 return entry->filter == data->filter && entry->next == data->next;
3054 action_record_hash (pentry)
3057 const struct action_record *entry = (const struct action_record *) pentry;
3058 return entry->next * 1009 + entry->filter;
3062 add_action_record (ar_hash, filter, next)
3066 struct action_record **slot, *new, tmp;
3068 tmp.filter = filter;
3070 slot = (struct action_record **) htab_find_slot (ar_hash, &tmp, INSERT);
3072 if ((new = *slot) == NULL)
3074 new = (struct action_record *) xmalloc (sizeof (*new));
3075 new->offset = VARRAY_ACTIVE_SIZE (cfun->eh->action_record_data) + 1;
3076 new->filter = filter;
3080 /* The filter value goes in untouched. The link to the next
3081 record is a "self-relative" byte offset, or zero to indicate
3082 that there is no next record. So convert the absolute 1 based
3083 indicies we've been carrying around into a displacement. */
3085 push_sleb128 (&cfun->eh->action_record_data, filter);
3087 next -= VARRAY_ACTIVE_SIZE (cfun->eh->action_record_data) + 1;
3088 push_sleb128 (&cfun->eh->action_record_data, next);
3095 collect_one_action_chain (ar_hash, region)
3097 struct eh_region *region;
3099 struct eh_region *c;
3102 /* If we've reached the top of the region chain, then we have
3103 no actions, and require no landing pad. */
3107 switch (region->type)
3110 /* A cleanup adds a zero filter to the beginning of the chain, but
3111 there are special cases to look out for. If there are *only*
3112 cleanups along a path, then it compresses to a zero action.
3113 Further, if there are multiple cleanups along a path, we only
3114 need to represent one of them, as that is enough to trigger
3115 entry to the landing pad at runtime. */
3116 next = collect_one_action_chain (ar_hash, region->outer);
3119 for (c = region->outer; c ; c = c->outer)
3120 if (c->type == ERT_CLEANUP)
3122 return add_action_record (ar_hash, 0, next);
3125 /* Process the associated catch regions in reverse order.
3126 If there's a catch-all handler, then we don't need to
3127 search outer regions. Use a magic -3 value to record
3128 that we havn't done the outer search. */
3130 for (c = region->u.try.last_catch; c ; c = c->u.catch.prev_catch)
3132 if (c->u.catch.type == NULL)
3133 next = add_action_record (ar_hash, c->u.catch.filter, 0);
3138 next = collect_one_action_chain (ar_hash, region->outer);
3140 /* If there is no next action, terminate the chain. */
3143 /* If all outer actions are cleanups or must_not_throw,
3144 we'll have no action record for it, since we had wanted
3145 to encode these states in the call-site record directly.
3146 Add a cleanup action to the chain to catch these. */
3148 next = add_action_record (ar_hash, 0, 0);
3150 next = add_action_record (ar_hash, c->u.catch.filter, next);
3155 case ERT_ALLOWED_EXCEPTIONS:
3156 /* An exception specification adds its filter to the
3157 beginning of the chain. */
3158 next = collect_one_action_chain (ar_hash, region->outer);
3159 return add_action_record (ar_hash, region->u.allowed.filter,
3160 next < 0 ? 0 : next);
3162 case ERT_MUST_NOT_THROW:
3163 /* A must-not-throw region with no inner handlers or cleanups
3164 requires no call-site entry. Note that this differs from
3165 the no handler or cleanup case in that we do require an lsda
3166 to be generated. Return a magic -2 value to record this. */
3171 /* CATCH regions are handled in TRY above. THROW regions are
3172 for optimization information only and produce no output. */
3173 return collect_one_action_chain (ar_hash, region->outer);
3181 add_call_site (landing_pad, action)
3185 struct call_site_record *data = cfun->eh->call_site_data;
3186 int used = cfun->eh->call_site_data_used;
3187 int size = cfun->eh->call_site_data_size;
3191 size = (size ? size * 2 : 64);
3192 data = (struct call_site_record *)
3193 xrealloc (data, sizeof (*data) * size);
3194 cfun->eh->call_site_data = data;
3195 cfun->eh->call_site_data_size = size;
3198 data[used].landing_pad = landing_pad;
3199 data[used].action = action;
3201 cfun->eh->call_site_data_used = used + 1;
3203 return used + call_site_base;
3206 /* Turn REG_EH_REGION notes back into NOTE_INSN_EH_REGION notes.
3207 The new note numbers will not refer to region numbers, but
3208 instead to call site entries. */
3211 convert_to_eh_region_ranges ()
3213 rtx insn, iter, note;
3215 int last_action = -3;
3216 rtx last_action_insn = NULL_RTX;
3217 rtx last_landing_pad = NULL_RTX;
3218 rtx first_no_action_insn = NULL_RTX;
3221 if (USING_SJLJ_EXCEPTIONS || cfun->eh->region_tree == NULL)
3224 VARRAY_UCHAR_INIT (cfun->eh->action_record_data, 64, "action_record_data");
3226 ar_hash = htab_create (31, action_record_hash, action_record_eq, free);
3228 for (iter = get_insns (); iter ; iter = NEXT_INSN (iter))
3231 struct eh_region *region;
3233 rtx this_landing_pad;
3236 if (GET_CODE (insn) == INSN
3237 && GET_CODE (PATTERN (insn)) == SEQUENCE)
3238 insn = XVECEXP (PATTERN (insn), 0, 0);
3240 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
3243 if (! (GET_CODE (insn) == CALL_INSN
3244 || (flag_non_call_exceptions
3245 && may_trap_p (PATTERN (insn)))))
3252 if (INTVAL (XEXP (note, 0)) <= 0)
3254 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
3255 this_action = collect_one_action_chain (ar_hash, region);
3258 /* Existence of catch handlers, or must-not-throw regions
3259 implies that an lsda is needed (even if empty). */
3260 if (this_action != -1)
3261 cfun->uses_eh_lsda = 1;
3263 /* Delay creation of region notes for no-action regions
3264 until we're sure that an lsda will be required. */
3265 else if (last_action == -3)
3267 first_no_action_insn = iter;
3271 /* Cleanups and handlers may share action chains but not
3272 landing pads. Collect the landing pad for this region. */
3273 if (this_action >= 0)
3275 struct eh_region *o;
3276 for (o = region; ! o->landing_pad ; o = o->outer)
3278 this_landing_pad = o->landing_pad;
3281 this_landing_pad = NULL_RTX;
3283 /* Differing actions or landing pads implies a change in call-site
3284 info, which implies some EH_REGION note should be emitted. */
3285 if (last_action != this_action
3286 || last_landing_pad != this_landing_pad)
3288 /* If we'd not seen a previous action (-3) or the previous
3289 action was must-not-throw (-2), then we do not need an
3291 if (last_action >= -1)
3293 /* If we delayed the creation of the begin, do it now. */
3294 if (first_no_action_insn)
3296 call_site = add_call_site (NULL_RTX, 0);
3297 note = emit_note_before (NOTE_INSN_EH_REGION_BEG,
3298 first_no_action_insn);
3299 NOTE_EH_HANDLER (note) = call_site;
3300 first_no_action_insn = NULL_RTX;
3303 note = emit_note_after (NOTE_INSN_EH_REGION_END,
3305 NOTE_EH_HANDLER (note) = call_site;
3308 /* If the new action is must-not-throw, then no region notes
3310 if (this_action >= -1)
3312 call_site = add_call_site (this_landing_pad,
3313 this_action < 0 ? 0 : this_action);
3314 note = emit_note_before (NOTE_INSN_EH_REGION_BEG, iter);
3315 NOTE_EH_HANDLER (note) = call_site;
3318 last_action = this_action;
3319 last_landing_pad = this_landing_pad;
3321 last_action_insn = iter;
3324 if (last_action >= -1 && ! first_no_action_insn)
3326 note = emit_note_after (NOTE_INSN_EH_REGION_END, last_action_insn);
3327 NOTE_EH_HANDLER (note) = call_site;
3330 htab_delete (ar_hash);
3335 push_uleb128 (data_area, value)
3336 varray_type *data_area;
3341 unsigned char byte = value & 0x7f;
3345 VARRAY_PUSH_UCHAR (*data_area, byte);
3351 push_sleb128 (data_area, value)
3352 varray_type *data_area;
3360 byte = value & 0x7f;
3362 more = ! ((value == 0 && (byte & 0x40) == 0)
3363 || (value == -1 && (byte & 0x40) != 0));
3366 VARRAY_PUSH_UCHAR (*data_area, byte);
3372 #ifndef HAVE_AS_LEB128
3374 dw2_size_of_call_site_table ()
3376 int n = cfun->eh->call_site_data_used;
3377 int size = n * (4 + 4 + 4);
3380 for (i = 0; i < n; ++i)
3382 struct call_site_record *cs = &cfun->eh->call_site_data[i];
3383 size += size_of_uleb128 (cs->action);
3390 sjlj_size_of_call_site_table ()
3392 int n = cfun->eh->call_site_data_used;
3396 for (i = 0; i < n; ++i)
3398 struct call_site_record *cs = &cfun->eh->call_site_data[i];
3399 size += size_of_uleb128 (INTVAL (cs->landing_pad));
3400 size += size_of_uleb128 (cs->action);
3408 dw2_output_call_site_table ()
3410 const char *function_start_lab
3411 = IDENTIFIER_POINTER (current_function_func_begin_label);
3412 int n = cfun->eh->call_site_data_used;
3415 for (i = 0; i < n; ++i)
3417 struct call_site_record *cs = &cfun->eh->call_site_data[i];
3418 char reg_start_lab[32];
3419 char reg_end_lab[32];
3420 char landing_pad_lab[32];
3422 ASM_GENERATE_INTERNAL_LABEL (reg_start_lab, "LEHB", call_site_base + i);
3423 ASM_GENERATE_INTERNAL_LABEL (reg_end_lab, "LEHE", call_site_base + i);
3425 if (cs->landing_pad)
3426 ASM_GENERATE_INTERNAL_LABEL (landing_pad_lab, "L",
3427 CODE_LABEL_NUMBER (cs->landing_pad));
3429 /* ??? Perhaps use insn length scaling if the assembler supports
3430 generic arithmetic. */
3431 /* ??? Perhaps use attr_length to choose data1 or data2 instead of
3432 data4 if the function is small enough. */
3433 #ifdef HAVE_AS_LEB128
3434 dw2_asm_output_delta_uleb128 (reg_start_lab, function_start_lab,
3435 "region %d start", i);
3436 dw2_asm_output_delta_uleb128 (reg_end_lab, reg_start_lab,
3438 if (cs->landing_pad)
3439 dw2_asm_output_delta_uleb128 (landing_pad_lab, function_start_lab,
3442 dw2_asm_output_data_uleb128 (0, "landing pad");
3444 dw2_asm_output_delta (4, reg_start_lab, function_start_lab,
3445 "region %d start", i);
3446 dw2_asm_output_delta (4, reg_end_lab, reg_start_lab, "length");
3447 if (cs->landing_pad)
3448 dw2_asm_output_delta (4, landing_pad_lab, function_start_lab,
3451 dw2_asm_output_data (4, 0, "landing pad");
3453 dw2_asm_output_data_uleb128 (cs->action, "action");
3456 call_site_base += n;
3460 sjlj_output_call_site_table ()
3462 int n = cfun->eh->call_site_data_used;
3465 for (i = 0; i < n; ++i)
3467 struct call_site_record *cs = &cfun->eh->call_site_data[i];
3469 dw2_asm_output_data_uleb128 (INTVAL (cs->landing_pad),
3470 "region %d landing pad", i);
3471 dw2_asm_output_data_uleb128 (cs->action, "action");
3474 call_site_base += n;
3478 output_function_exception_table ()
3480 int tt_format, cs_format, lp_format, i, n;
3481 #ifdef HAVE_AS_LEB128
3482 char ttype_label[32];
3483 char cs_after_size_label[32];
3484 char cs_end_label[32];
3490 int tt_format_size = 0;
3492 /* Not all functions need anything. */
3493 if (! cfun->uses_eh_lsda)
3496 funcdef_number = (USING_SJLJ_EXCEPTIONS
3497 ? sjlj_funcdef_number
3498 : current_funcdef_number);
3500 #ifdef IA64_UNWIND_INFO
3501 fputs ("\t.personality\t", asm_out_file);
3502 output_addr_const (asm_out_file, eh_personality_libfunc);
3503 fputs ("\n\t.handlerdata\n", asm_out_file);
3504 /* Note that varasm still thinks we're in the function's code section.
3505 The ".endp" directive that will immediately follow will take us back. */
3507 exception_section ();
3510 have_tt_data = (VARRAY_ACTIVE_SIZE (cfun->eh->ttype_data) > 0
3511 || VARRAY_ACTIVE_SIZE (cfun->eh->ehspec_data) > 0);
3513 /* Indicate the format of the @TType entries. */
3515 tt_format = DW_EH_PE_omit;
3518 tt_format = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/0, /*global=*/1);
3519 #ifdef HAVE_AS_LEB128
3520 ASM_GENERATE_INTERNAL_LABEL (ttype_label, "LLSDATT", funcdef_number);
3522 tt_format_size = size_of_encoded_value (tt_format);
3524 assemble_align (tt_format_size * BITS_PER_UNIT);
3527 ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LLSDA", funcdef_number);
3529 /* The LSDA header. */
3531 /* Indicate the format of the landing pad start pointer. An omitted
3532 field implies @LPStart == @Start. */
3533 /* Currently we always put @LPStart == @Start. This field would
3534 be most useful in moving the landing pads completely out of
3535 line to another section, but it could also be used to minimize
3536 the size of uleb128 landing pad offsets. */
3537 lp_format = DW_EH_PE_omit;
3538 dw2_asm_output_data (1, lp_format, "@LPStart format (%s)",
3539 eh_data_format_name (lp_format));
3541 /* @LPStart pointer would go here. */
3543 dw2_asm_output_data (1, tt_format, "@TType format (%s)",
3544 eh_data_format_name (tt_format));
3546 #ifndef HAVE_AS_LEB128
3547 if (USING_SJLJ_EXCEPTIONS)
3548 call_site_len = sjlj_size_of_call_site_table ();
3550 call_site_len = dw2_size_of_call_site_table ();
3553 /* A pc-relative 4-byte displacement to the @TType data. */
3556 #ifdef HAVE_AS_LEB128
3557 char ttype_after_disp_label[32];
3558 ASM_GENERATE_INTERNAL_LABEL (ttype_after_disp_label, "LLSDATTD",
3560 dw2_asm_output_delta_uleb128 (ttype_label, ttype_after_disp_label,
3561 "@TType base offset");
3562 ASM_OUTPUT_LABEL (asm_out_file, ttype_after_disp_label);
3564 /* Ug. Alignment queers things. */
3565 unsigned int before_disp, after_disp, last_disp, disp;
3567 before_disp = 1 + 1;
3568 after_disp = (1 + size_of_uleb128 (call_site_len)
3570 + VARRAY_ACTIVE_SIZE (cfun->eh->action_record_data)
3571 + (VARRAY_ACTIVE_SIZE (cfun->eh->ttype_data)
3577 unsigned int disp_size, pad;
3580 disp_size = size_of_uleb128 (disp);
3581 pad = before_disp + disp_size + after_disp;
3582 if (pad % tt_format_size)
3583 pad = tt_format_size - (pad % tt_format_size);
3586 disp = after_disp + pad;
3588 while (disp != last_disp);
3590 dw2_asm_output_data_uleb128 (disp, "@TType base offset");
3594 /* Indicate the format of the call-site offsets. */
3595 #ifdef HAVE_AS_LEB128
3596 cs_format = DW_EH_PE_uleb128;
3598 cs_format = DW_EH_PE_udata4;
3600 dw2_asm_output_data (1, cs_format, "call-site format (%s)",
3601 eh_data_format_name (cs_format));
3603 #ifdef HAVE_AS_LEB128
3604 ASM_GENERATE_INTERNAL_LABEL (cs_after_size_label, "LLSDACSB",
3606 ASM_GENERATE_INTERNAL_LABEL (cs_end_label, "LLSDACSE",
3608 dw2_asm_output_delta_uleb128 (cs_end_label, cs_after_size_label,
3609 "Call-site table length");
3610 ASM_OUTPUT_LABEL (asm_out_file, cs_after_size_label);
3611 if (USING_SJLJ_EXCEPTIONS)
3612 sjlj_output_call_site_table ();
3614 dw2_output_call_site_table ();
3615 ASM_OUTPUT_LABEL (asm_out_file, cs_end_label);
3617 dw2_asm_output_data_uleb128 (call_site_len,"Call-site table length");
3618 if (USING_SJLJ_EXCEPTIONS)
3619 sjlj_output_call_site_table ();
3621 dw2_output_call_site_table ();
3624 /* ??? Decode and interpret the data for flag_debug_asm. */
3625 n = VARRAY_ACTIVE_SIZE (cfun->eh->action_record_data);
3626 for (i = 0; i < n; ++i)
3627 dw2_asm_output_data (1, VARRAY_UCHAR (cfun->eh->action_record_data, i),
3628 (i ? NULL : "Action record table"));
3631 assemble_align (tt_format_size * BITS_PER_UNIT);
3633 i = VARRAY_ACTIVE_SIZE (cfun->eh->ttype_data);
3636 tree type = VARRAY_TREE (cfun->eh->ttype_data, i);
3638 if (type == NULL_TREE)
3639 type = integer_zero_node;
3641 type = lookup_type_for_runtime (type);
3643 dw2_asm_output_encoded_addr_rtx (tt_format,
3644 expand_expr (type, NULL_RTX, VOIDmode,
3645 EXPAND_INITIALIZER),
3649 #ifdef HAVE_AS_LEB128
3651 ASM_OUTPUT_LABEL (asm_out_file, ttype_label);
3654 /* ??? Decode and interpret the data for flag_debug_asm. */
3655 n = VARRAY_ACTIVE_SIZE (cfun->eh->ehspec_data);
3656 for (i = 0; i < n; ++i)
3657 dw2_asm_output_data (1, VARRAY_UCHAR (cfun->eh->ehspec_data, i),
3658 (i ? NULL : "Exception specification table"));
3660 function_section (current_function_decl);
3662 if (USING_SJLJ_EXCEPTIONS)
3663 sjlj_funcdef_number += 1;