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. ] */
58 #include "insn-config.h"
60 #include "integrate.h"
61 #include "hard-reg-set.h"
62 #include "basic-block.h"
64 #include "dwarf2asm.h"
65 #include "dwarf2out.h"
74 /* Provide defaults for stuff that may not be defined when using
76 #ifndef EH_RETURN_STACKADJ_RTX
77 #define EH_RETURN_STACKADJ_RTX 0
79 #ifndef EH_RETURN_HANDLER_RTX
80 #define EH_RETURN_HANDLER_RTX 0
82 #ifndef EH_RETURN_DATA_REGNO
83 #define EH_RETURN_DATA_REGNO(N) INVALID_REGNUM
87 /* Nonzero means enable synchronous exceptions for non-call instructions. */
88 int flag_non_call_exceptions;
90 /* Protect cleanup actions with must-not-throw regions, with a call
91 to the given failure handler. */
92 tree (*lang_protect_cleanup_actions) PARAMS ((void));
94 /* Return true if type A catches type B. */
95 int (*lang_eh_type_covers) PARAMS ((tree a, tree b));
97 /* Map a type to a runtime object to match type. */
98 tree (*lang_eh_runtime_type) PARAMS ((tree));
100 /* A list of labels used for exception handlers. */
101 rtx exception_handler_labels;
103 static int call_site_base;
104 static unsigned int sjlj_funcdef_number;
105 static htab_t type_to_runtime_map;
107 /* Describe the SjLj_Function_Context structure. */
108 static tree sjlj_fc_type_node;
109 static int sjlj_fc_call_site_ofs;
110 static int sjlj_fc_data_ofs;
111 static int sjlj_fc_personality_ofs;
112 static int sjlj_fc_lsda_ofs;
113 static int sjlj_fc_jbuf_ofs;
115 /* Describes one exception region. */
118 /* The immediately surrounding region. */
119 struct eh_region *outer;
121 /* The list of immediately contained regions. */
122 struct eh_region *inner;
123 struct eh_region *next_peer;
125 /* An identifier for this region. */
128 /* Each region does exactly one thing. */
134 ERT_ALLOWED_EXCEPTIONS,
140 /* Holds the action to perform based on the preceeding type. */
142 /* A list of catch blocks, a surrounding try block,
143 and the label for continuing after a catch. */
145 struct eh_region *catch;
146 struct eh_region *last_catch;
147 struct eh_region *prev_try;
151 /* The list through the catch handlers, the type object
152 matched, and a pointer to the generated code. */
154 struct eh_region *next_catch;
155 struct eh_region *prev_catch;
160 /* A tree_list of allowed types. */
166 /* The type given by a call to "throw foo();", or discovered
172 /* Retain the cleanup expression even after expansion so that
173 we can match up fixup regions. */
178 /* The real region (by expression and by pointer) that fixup code
182 struct eh_region *real_region;
186 /* Entry point for this region's handler before landing pads are built. */
189 /* Entry point for this region's handler from the runtime eh library. */
192 /* Entry point for this region's handler from an inner region. */
193 rtx post_landing_pad;
195 /* The RESX insn for handing off control to the next outermost handler,
200 /* Used to save exception status for each function. */
203 /* The tree of all regions for this function. */
204 struct eh_region *region_tree;
206 /* The same information as an indexable array. */
207 struct eh_region **region_array;
209 /* The most recently open region. */
210 struct eh_region *cur_region;
212 /* This is the region for which we are processing catch blocks. */
213 struct eh_region *try_region;
215 /* A stack (TREE_LIST) of lists of handlers. The TREE_VALUE of each
216 node is itself a TREE_CHAINed list of handlers for regions that
217 are not yet closed. The TREE_VALUE of each entry contains the
218 handler for the corresponding entry on the ehstack. */
224 int built_landing_pads;
225 int last_region_number;
227 varray_type ttype_data;
228 varray_type ehspec_data;
229 varray_type action_record_data;
231 struct call_site_record
236 int call_site_data_used;
237 int call_site_data_size;
248 static void mark_eh_region PARAMS ((struct eh_region *));
250 static int t2r_eq PARAMS ((const PTR,
252 static hashval_t t2r_hash PARAMS ((const PTR));
253 static int t2r_mark_1 PARAMS ((PTR *, PTR));
254 static void t2r_mark PARAMS ((PTR));
255 static void add_type_for_runtime PARAMS ((tree));
256 static tree lookup_type_for_runtime PARAMS ((tree));
258 static struct eh_region *expand_eh_region_end PARAMS ((void));
260 static rtx get_exception_filter PARAMS ((struct function *));
262 static void collect_eh_region_array PARAMS ((void));
263 static void resolve_fixup_regions PARAMS ((void));
264 static void remove_fixup_regions PARAMS ((void));
265 static void convert_from_eh_region_ranges_1 PARAMS ((rtx *, int *, int));
267 static struct eh_region *duplicate_eh_region_1 PARAMS ((struct eh_region *,
268 struct inline_remap *));
269 static void duplicate_eh_region_2 PARAMS ((struct eh_region *,
270 struct eh_region **));
271 static int ttypes_filter_eq PARAMS ((const PTR,
273 static hashval_t ttypes_filter_hash PARAMS ((const PTR));
274 static int ehspec_filter_eq PARAMS ((const PTR,
276 static hashval_t ehspec_filter_hash PARAMS ((const PTR));
277 static int add_ttypes_entry PARAMS ((htab_t, tree));
278 static int add_ehspec_entry PARAMS ((htab_t, htab_t,
280 static void assign_filter_values PARAMS ((void));
281 static void build_post_landing_pads PARAMS ((void));
282 static void connect_post_landing_pads PARAMS ((void));
283 static void dw2_build_landing_pads PARAMS ((void));
286 static bool sjlj_find_directly_reachable_regions
287 PARAMS ((struct sjlj_lp_info *));
288 static void sjlj_assign_call_site_values
289 PARAMS ((rtx, struct sjlj_lp_info *));
290 static void sjlj_mark_call_sites
291 PARAMS ((struct sjlj_lp_info *));
292 static void sjlj_emit_function_enter PARAMS ((rtx));
293 static void sjlj_emit_function_exit PARAMS ((void));
294 static void sjlj_emit_dispatch_table
295 PARAMS ((rtx, struct sjlj_lp_info *));
296 static void sjlj_build_landing_pads PARAMS ((void));
298 static void remove_exception_handler_label PARAMS ((rtx));
299 static void remove_eh_handler PARAMS ((struct eh_region *));
301 struct reachable_info;
303 /* The return value of reachable_next_level. */
306 /* The given exception is not processed by the given region. */
308 /* The given exception may need processing by the given region. */
310 /* The given exception is completely processed by the given region. */
312 /* The given exception is completely processed by the runtime. */
316 static int check_handled PARAMS ((tree, tree));
317 static void add_reachable_handler
318 PARAMS ((struct reachable_info *, struct eh_region *,
319 struct eh_region *));
320 static enum reachable_code reachable_next_level
321 PARAMS ((struct eh_region *, tree, struct reachable_info *));
323 static int action_record_eq PARAMS ((const PTR,
325 static hashval_t action_record_hash PARAMS ((const PTR));
326 static int add_action_record PARAMS ((htab_t, int, int));
327 static int collect_one_action_chain PARAMS ((htab_t,
328 struct eh_region *));
329 static int add_call_site PARAMS ((rtx, int));
331 static void push_uleb128 PARAMS ((varray_type *,
333 static void push_sleb128 PARAMS ((varray_type *, int));
334 #ifndef HAVE_AS_LEB128
335 static int dw2_size_of_call_site_table PARAMS ((void));
336 static int sjlj_size_of_call_site_table PARAMS ((void));
338 static void dw2_output_call_site_table PARAMS ((void));
339 static void sjlj_output_call_site_table PARAMS ((void));
342 /* Routine to see if exception handling is turned on.
343 DO_WARN is non-zero if we want to inform the user that exception
344 handling is turned off.
346 This is used to ensure that -fexceptions has been specified if the
347 compiler tries to use any exception-specific functions. */
353 if (! flag_exceptions)
355 static int warned = 0;
356 if (! warned && do_warn)
358 error ("exception handling disabled, use -fexceptions to enable");
370 ggc_add_rtx_root (&exception_handler_labels, 1);
372 if (! flag_exceptions)
375 type_to_runtime_map = htab_create (31, t2r_hash, t2r_eq, NULL);
376 ggc_add_root (&type_to_runtime_map, 1, sizeof (htab_t), t2r_mark);
378 /* Create the SjLj_Function_Context structure. This should match
379 the definition in unwind-sjlj.c. */
380 if (USING_SJLJ_EXCEPTIONS)
382 tree f_jbuf, f_per, f_lsda, f_prev, f_cs, f_data, tmp;
384 sjlj_fc_type_node = make_lang_type (RECORD_TYPE);
385 ggc_add_tree_root (&sjlj_fc_type_node, 1);
387 f_prev = build_decl (FIELD_DECL, get_identifier ("__prev"),
388 build_pointer_type (sjlj_fc_type_node));
389 DECL_FIELD_CONTEXT (f_prev) = sjlj_fc_type_node;
391 f_cs = build_decl (FIELD_DECL, get_identifier ("__call_site"),
393 DECL_FIELD_CONTEXT (f_cs) = sjlj_fc_type_node;
395 tmp = build_index_type (build_int_2 (4 - 1, 0));
396 tmp = build_array_type (type_for_mode (word_mode, 1), tmp);
397 f_data = build_decl (FIELD_DECL, get_identifier ("__data"), tmp);
398 DECL_FIELD_CONTEXT (f_data) = sjlj_fc_type_node;
400 f_per = build_decl (FIELD_DECL, get_identifier ("__personality"),
402 DECL_FIELD_CONTEXT (f_per) = sjlj_fc_type_node;
404 f_lsda = build_decl (FIELD_DECL, get_identifier ("__lsda"),
406 DECL_FIELD_CONTEXT (f_lsda) = sjlj_fc_type_node;
408 #ifdef DONT_USE_BUILTIN_SETJMP
410 tmp = build_int_2 (JMP_BUF_SIZE - 1, 0);
412 /* Should be large enough for most systems, if it is not,
413 JMP_BUF_SIZE should be defined with the proper value. It will
414 also tend to be larger than necessary for most systems, a more
415 optimal port will define JMP_BUF_SIZE. */
416 tmp = build_int_2 (FIRST_PSEUDO_REGISTER + 2 - 1, 0);
419 /* This is 2 for builtin_setjmp, plus whatever the target requires
420 via STACK_SAVEAREA_MODE (SAVE_NONLOCAL). */
421 tmp = build_int_2 ((GET_MODE_SIZE (STACK_SAVEAREA_MODE (SAVE_NONLOCAL))
422 / GET_MODE_SIZE (Pmode)) + 2 - 1, 0);
424 tmp = build_index_type (tmp);
425 tmp = build_array_type (ptr_type_node, tmp);
426 f_jbuf = build_decl (FIELD_DECL, get_identifier ("__jbuf"), tmp);
427 #ifdef DONT_USE_BUILTIN_SETJMP
428 /* We don't know what the alignment requirements of the
429 runtime's jmp_buf has. Overestimate. */
430 DECL_ALIGN (f_jbuf) = BIGGEST_ALIGNMENT;
431 DECL_USER_ALIGN (f_jbuf) = 1;
433 DECL_FIELD_CONTEXT (f_jbuf) = sjlj_fc_type_node;
435 TYPE_FIELDS (sjlj_fc_type_node) = f_prev;
436 TREE_CHAIN (f_prev) = f_cs;
437 TREE_CHAIN (f_cs) = f_data;
438 TREE_CHAIN (f_data) = f_per;
439 TREE_CHAIN (f_per) = f_lsda;
440 TREE_CHAIN (f_lsda) = f_jbuf;
442 layout_type (sjlj_fc_type_node);
444 /* Cache the interesting field offsets so that we have
445 easy access from rtl. */
446 sjlj_fc_call_site_ofs
447 = (tree_low_cst (DECL_FIELD_OFFSET (f_cs), 1)
448 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_cs), 1) / BITS_PER_UNIT);
450 = (tree_low_cst (DECL_FIELD_OFFSET (f_data), 1)
451 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_data), 1) / BITS_PER_UNIT);
452 sjlj_fc_personality_ofs
453 = (tree_low_cst (DECL_FIELD_OFFSET (f_per), 1)
454 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_per), 1) / BITS_PER_UNIT);
456 = (tree_low_cst (DECL_FIELD_OFFSET (f_lsda), 1)
457 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_lsda), 1) / BITS_PER_UNIT);
459 = (tree_low_cst (DECL_FIELD_OFFSET (f_jbuf), 1)
460 + tree_low_cst (DECL_FIELD_BIT_OFFSET (f_jbuf), 1) / BITS_PER_UNIT);
465 init_eh_for_function ()
467 cfun->eh = (struct eh_status *) xcalloc (1, sizeof (struct eh_status));
470 /* Mark EH for GC. */
473 mark_eh_region (region)
474 struct eh_region *region;
479 switch (region->type)
482 ggc_mark_tree (region->u.cleanup.exp);
485 ggc_mark_rtx (region->u.try.continue_label);
488 ggc_mark_tree (region->u.catch.type);
490 case ERT_ALLOWED_EXCEPTIONS:
491 ggc_mark_tree (region->u.allowed.type_list);
493 case ERT_MUST_NOT_THROW:
496 ggc_mark_tree (region->u.throw.type);
499 ggc_mark_tree (region->u.fixup.cleanup_exp);
505 ggc_mark_rtx (region->label);
506 ggc_mark_rtx (region->resume);
507 ggc_mark_rtx (region->landing_pad);
508 ggc_mark_rtx (region->post_landing_pad);
513 struct eh_status *eh;
520 /* If we've called collect_eh_region_array, use it. Otherwise walk
521 the tree non-recursively. */
522 if (eh->region_array)
524 for (i = eh->last_region_number; i > 0; --i)
526 struct eh_region *r = eh->region_array[i];
527 if (r && r->region_number == i)
531 else if (eh->region_tree)
533 struct eh_region *r = eh->region_tree;
539 else if (r->next_peer)
547 } while (r->next_peer == NULL);
554 ggc_mark_tree (eh->protect_list);
555 ggc_mark_rtx (eh->filter);
556 ggc_mark_rtx (eh->exc_ptr);
557 ggc_mark_tree_varray (eh->ttype_data);
559 if (eh->call_site_data)
561 for (i = eh->call_site_data_used - 1; i >= 0; --i)
562 ggc_mark_rtx (eh->call_site_data[i].landing_pad);
565 ggc_mark_rtx (eh->ehr_stackadj);
566 ggc_mark_rtx (eh->ehr_handler);
567 ggc_mark_rtx (eh->ehr_label);
569 ggc_mark_rtx (eh->sjlj_fc);
570 ggc_mark_rtx (eh->sjlj_exit_after);
577 struct eh_status *eh = f->eh;
579 if (eh->region_array)
582 for (i = eh->last_region_number; i > 0; --i)
584 struct eh_region *r = eh->region_array[i];
585 /* Mind we don't free a region struct more than once. */
586 if (r && r->region_number == i)
589 free (eh->region_array);
591 else if (eh->region_tree)
593 struct eh_region *next, *r = eh->region_tree;
598 else if (r->next_peer)
612 } while (r->next_peer == NULL);
621 VARRAY_FREE (eh->ttype_data);
622 VARRAY_FREE (eh->ehspec_data);
623 VARRAY_FREE (eh->action_record_data);
624 if (eh->call_site_data)
625 free (eh->call_site_data);
632 /* Start an exception handling region. All instructions emitted
633 after this point are considered to be part of the region until
634 expand_eh_region_end is invoked. */
637 expand_eh_region_start ()
639 struct eh_region *new_region;
640 struct eh_region *cur_region;
646 /* Insert a new blank region as a leaf in the tree. */
647 new_region = (struct eh_region *) xcalloc (1, sizeof (*new_region));
648 cur_region = cfun->eh->cur_region;
649 new_region->outer = cur_region;
652 new_region->next_peer = cur_region->inner;
653 cur_region->inner = new_region;
657 new_region->next_peer = cfun->eh->region_tree;
658 cfun->eh->region_tree = new_region;
660 cfun->eh->cur_region = new_region;
662 /* Create a note marking the start of this region. */
663 new_region->region_number = ++cfun->eh->last_region_number;
664 note = emit_note (NULL, NOTE_INSN_EH_REGION_BEG);
665 NOTE_EH_HANDLER (note) = new_region->region_number;
668 /* Common code to end a region. Returns the region just ended. */
670 static struct eh_region *
671 expand_eh_region_end ()
673 struct eh_region *cur_region = cfun->eh->cur_region;
676 /* Create a nute marking the end of this region. */
677 note = emit_note (NULL, NOTE_INSN_EH_REGION_END);
678 NOTE_EH_HANDLER (note) = cur_region->region_number;
681 cfun->eh->cur_region = cur_region->outer;
686 /* End an exception handling region for a cleanup. HANDLER is an
687 expression to expand for the cleanup. */
690 expand_eh_region_end_cleanup (handler)
693 struct eh_region *region;
694 tree protect_cleanup_actions;
701 region = expand_eh_region_end ();
702 region->type = ERT_CLEANUP;
703 region->label = gen_label_rtx ();
704 region->u.cleanup.exp = handler;
706 around_label = gen_label_rtx ();
707 emit_jump (around_label);
709 emit_label (region->label);
711 /* Give the language a chance to specify an action to be taken if an
712 exception is thrown that would propogate out of the HANDLER. */
713 protect_cleanup_actions
714 = (lang_protect_cleanup_actions
715 ? (*lang_protect_cleanup_actions) ()
718 if (protect_cleanup_actions)
719 expand_eh_region_start ();
721 /* In case this cleanup involves an inline destructor with a try block in
722 it, we need to save the EH return data registers around it. */
723 data_save[0] = gen_reg_rtx (Pmode);
724 emit_move_insn (data_save[0], get_exception_pointer (cfun));
725 data_save[1] = gen_reg_rtx (word_mode);
726 emit_move_insn (data_save[1], get_exception_filter (cfun));
728 expand_expr (handler, const0_rtx, VOIDmode, 0);
730 emit_move_insn (cfun->eh->exc_ptr, data_save[0]);
731 emit_move_insn (cfun->eh->filter, data_save[1]);
733 if (protect_cleanup_actions)
734 expand_eh_region_end_must_not_throw (protect_cleanup_actions);
736 /* We need any stack adjustment complete before the around_label. */
737 do_pending_stack_adjust ();
739 /* We delay the generation of the _Unwind_Resume until we generate
740 landing pads. We emit a marker here so as to get good control
741 flow data in the meantime. */
743 = emit_jump_insn (gen_rtx_RESX (VOIDmode, region->region_number));
746 emit_label (around_label);
749 /* End an exception handling region for a try block, and prepares
750 for subsequent calls to expand_start_catch. */
753 expand_start_all_catch ()
755 struct eh_region *region;
760 region = expand_eh_region_end ();
761 region->type = ERT_TRY;
762 region->u.try.prev_try = cfun->eh->try_region;
763 region->u.try.continue_label = gen_label_rtx ();
765 cfun->eh->try_region = region;
767 emit_jump (region->u.try.continue_label);
770 /* Begin a catch clause. TYPE is the type caught, or null if this is
771 a catch-all clause. */
774 expand_start_catch (type)
777 struct eh_region *t, *c, *l;
783 add_type_for_runtime (type);
784 expand_eh_region_start ();
786 t = cfun->eh->try_region;
787 c = cfun->eh->cur_region;
789 c->u.catch.type = type;
790 c->label = gen_label_rtx ();
792 l = t->u.try.last_catch;
793 c->u.catch.prev_catch = l;
795 l->u.catch.next_catch = c;
798 t->u.try.last_catch = c;
800 emit_label (c->label);
803 /* End a catch clause. Control will resume after the try/catch block. */
808 struct eh_region *try_region, *catch_region;
813 catch_region = expand_eh_region_end ();
814 try_region = cfun->eh->try_region;
816 emit_jump (try_region->u.try.continue_label);
819 /* End a sequence of catch handlers for a try block. */
822 expand_end_all_catch ()
824 struct eh_region *try_region;
829 try_region = cfun->eh->try_region;
830 cfun->eh->try_region = try_region->u.try.prev_try;
832 emit_label (try_region->u.try.continue_label);
835 /* End an exception region for an exception type filter. ALLOWED is a
836 TREE_LIST of types to be matched by the runtime. FAILURE is an
837 expression to invoke if a mismatch ocurrs.
839 ??? We could use these semantics for calls to rethrow, too; if we can
840 see the surrounding catch clause, we know that the exception we're
841 rethrowing satisfies the "filter" of the catch type. */
844 expand_eh_region_end_allowed (allowed, failure)
845 tree allowed, failure;
847 struct eh_region *region;
853 region = expand_eh_region_end ();
854 region->type = ERT_ALLOWED_EXCEPTIONS;
855 region->u.allowed.type_list = allowed;
856 region->label = gen_label_rtx ();
858 for (; allowed ; allowed = TREE_CHAIN (allowed))
859 add_type_for_runtime (TREE_VALUE (allowed));
861 /* We must emit the call to FAILURE here, so that if this function
862 throws a different exception, that it will be processed by the
865 around_label = gen_label_rtx ();
866 emit_jump (around_label);
868 emit_label (region->label);
869 expand_expr (failure, const0_rtx, VOIDmode, EXPAND_NORMAL);
870 /* We must adjust the stack before we reach the AROUND_LABEL because
871 the call to FAILURE does not occur on all paths to the
873 do_pending_stack_adjust ();
875 emit_label (around_label);
878 /* End an exception region for a must-not-throw filter. FAILURE is an
879 expression invoke if an uncaught exception propagates this far.
881 This is conceptually identical to expand_eh_region_end_allowed with
882 an empty allowed list (if you passed "std::terminate" instead of
883 "__cxa_call_unexpected"), but they are represented differently in
887 expand_eh_region_end_must_not_throw (failure)
890 struct eh_region *region;
896 region = expand_eh_region_end ();
897 region->type = ERT_MUST_NOT_THROW;
898 region->label = gen_label_rtx ();
900 /* We must emit the call to FAILURE here, so that if this function
901 throws a different exception, that it will be processed by the
904 around_label = gen_label_rtx ();
905 emit_jump (around_label);
907 emit_label (region->label);
908 expand_expr (failure, const0_rtx, VOIDmode, EXPAND_NORMAL);
910 emit_label (around_label);
913 /* End an exception region for a throw. No handling goes on here,
914 but it's the easiest way for the front-end to indicate what type
918 expand_eh_region_end_throw (type)
921 struct eh_region *region;
926 region = expand_eh_region_end ();
927 region->type = ERT_THROW;
928 region->u.throw.type = type;
931 /* End a fixup region. Within this region the cleanups for the immediately
932 enclosing region are _not_ run. This is used for goto cleanup to avoid
933 destroying an object twice.
935 This would be an extraordinarily simple prospect, were it not for the
936 fact that we don't actually know what the immediately enclosing region
937 is. This surprising fact is because expand_cleanups is currently
938 generating a sequence that it will insert somewhere else. We collect
939 the proper notion of "enclosing" in convert_from_eh_region_ranges. */
942 expand_eh_region_end_fixup (handler)
945 struct eh_region *fixup;
950 fixup = expand_eh_region_end ();
951 fixup->type = ERT_FIXUP;
952 fixup->u.fixup.cleanup_exp = handler;
955 /* Return an rtl expression for a pointer to the exception object
959 get_exception_pointer (fun)
960 struct function *fun;
962 rtx exc_ptr = fun->eh->exc_ptr;
963 if (fun == cfun && ! exc_ptr)
965 exc_ptr = gen_reg_rtx (Pmode);
966 fun->eh->exc_ptr = exc_ptr;
971 /* Return an rtl expression for the exception dispatch filter
975 get_exception_filter (fun)
976 struct function *fun;
978 rtx filter = fun->eh->filter;
979 if (fun == cfun && ! filter)
981 filter = gen_reg_rtx (word_mode);
982 fun->eh->filter = filter;
987 /* Begin a region that will contain entries created with
988 add_partial_entry. */
991 begin_protect_partials ()
993 /* Push room for a new list. */
994 cfun->eh->protect_list
995 = tree_cons (NULL_TREE, NULL_TREE, cfun->eh->protect_list);
998 /* Start a new exception region for a region of code that has a
999 cleanup action and push the HANDLER for the region onto
1000 protect_list. All of the regions created with add_partial_entry
1001 will be ended when end_protect_partials is invoked. */
1004 add_partial_entry (handler)
1007 expand_eh_region_start ();
1009 /* ??? This comment was old before the most recent rewrite. We
1010 really ought to fix the callers at some point. */
1011 /* For backwards compatibility, we allow callers to omit calls to
1012 begin_protect_partials for the outermost region. So, we must
1013 explicitly do so here. */
1014 if (!cfun->eh->protect_list)
1015 begin_protect_partials ();
1017 /* Add this entry to the front of the list. */
1018 TREE_VALUE (cfun->eh->protect_list)
1019 = tree_cons (NULL_TREE, handler, TREE_VALUE (cfun->eh->protect_list));
1022 /* End all the pending exception regions on protect_list. */
1025 end_protect_partials ()
1029 /* ??? This comment was old before the most recent rewrite. We
1030 really ought to fix the callers at some point. */
1031 /* For backwards compatibility, we allow callers to omit the call to
1032 begin_protect_partials for the outermost region. So,
1033 PROTECT_LIST may be NULL. */
1034 if (!cfun->eh->protect_list)
1037 /* Pop the topmost entry. */
1038 t = TREE_VALUE (cfun->eh->protect_list);
1039 cfun->eh->protect_list = TREE_CHAIN (cfun->eh->protect_list);
1041 /* End all the exception regions. */
1042 for (; t; t = TREE_CHAIN (t))
1043 expand_eh_region_end_cleanup (TREE_VALUE (t));
1047 /* This section is for the exception handling specific optimization pass. */
1049 /* Random access the exception region tree. It's just as simple to
1050 collect the regions this way as in expand_eh_region_start, but
1051 without having to realloc memory. */
1054 collect_eh_region_array ()
1056 struct eh_region **array, *i;
1058 i = cfun->eh->region_tree;
1062 array = xcalloc (cfun->eh->last_region_number + 1, sizeof (*array));
1063 cfun->eh->region_array = array;
1067 array[i->region_number] = i;
1069 /* If there are sub-regions, process them. */
1072 /* If there are peers, process them. */
1073 else if (i->next_peer)
1075 /* Otherwise, step back up the tree to the next peer. */
1082 } while (i->next_peer == NULL);
1089 resolve_fixup_regions ()
1091 int i, j, n = cfun->eh->last_region_number;
1093 for (i = 1; i <= n; ++i)
1095 struct eh_region *fixup = cfun->eh->region_array[i];
1096 struct eh_region *cleanup = 0;
1098 if (! fixup || fixup->type != ERT_FIXUP)
1101 for (j = 1; j <= n; ++j)
1103 cleanup = cfun->eh->region_array[j];
1104 if (cleanup->type == ERT_CLEANUP
1105 && cleanup->u.cleanup.exp == fixup->u.fixup.cleanup_exp)
1111 fixup->u.fixup.real_region = cleanup->outer;
1115 /* Now that we've discovered what region actually encloses a fixup,
1116 we can shuffle pointers and remove them from the tree. */
1119 remove_fixup_regions ()
1123 struct eh_region *fixup;
1125 /* Walk the insn chain and adjust the REG_EH_REGION numbers
1126 for instructions referencing fixup regions. This is only
1127 strictly necessary for fixup regions with no parent, but
1128 doesn't hurt to do it for all regions. */
1129 for (insn = get_insns(); insn ; insn = NEXT_INSN (insn))
1131 && (note = find_reg_note (insn, REG_EH_REGION, NULL))
1132 && INTVAL (XEXP (note, 0)) > 0
1133 && (fixup = cfun->eh->region_array[INTVAL (XEXP (note, 0))])
1134 && fixup->type == ERT_FIXUP)
1136 if (fixup->u.fixup.real_region)
1137 XEXP (note, 0) = GEN_INT (fixup->u.fixup.real_region->region_number);
1139 remove_note (insn, note);
1142 /* Remove the fixup regions from the tree. */
1143 for (i = cfun->eh->last_region_number; i > 0; --i)
1145 fixup = cfun->eh->region_array[i];
1149 /* Allow GC to maybe free some memory. */
1150 if (fixup->type == ERT_CLEANUP)
1151 fixup->u.cleanup.exp = NULL_TREE;
1153 if (fixup->type != ERT_FIXUP)
1158 struct eh_region *parent, *p, **pp;
1160 parent = fixup->u.fixup.real_region;
1162 /* Fix up the children's parent pointers; find the end of
1164 for (p = fixup->inner; ; p = p->next_peer)
1171 /* In the tree of cleanups, only outer-inner ordering matters.
1172 So link the children back in anywhere at the correct level. */
1174 pp = &parent->inner;
1176 pp = &cfun->eh->region_tree;
1179 fixup->inner = NULL;
1182 remove_eh_handler (fixup);
1186 /* Turn NOTE_INSN_EH_REGION notes into REG_EH_REGION notes for each
1187 can_throw instruction in the region. */
1190 convert_from_eh_region_ranges_1 (pinsns, orig_sp, cur)
1198 for (insn = *pinsns; insn ; insn = next)
1200 next = NEXT_INSN (insn);
1201 if (GET_CODE (insn) == NOTE)
1203 int kind = NOTE_LINE_NUMBER (insn);
1204 if (kind == NOTE_INSN_EH_REGION_BEG
1205 || kind == NOTE_INSN_EH_REGION_END)
1207 if (kind == NOTE_INSN_EH_REGION_BEG)
1209 struct eh_region *r;
1212 cur = NOTE_EH_HANDLER (insn);
1214 r = cfun->eh->region_array[cur];
1215 if (r->type == ERT_FIXUP)
1217 r = r->u.fixup.real_region;
1218 cur = r ? r->region_number : 0;
1220 else if (r->type == ERT_CATCH)
1223 cur = r ? r->region_number : 0;
1229 /* Removing the first insn of a CALL_PLACEHOLDER sequence
1230 requires extra care to adjust sequence start. */
1231 if (insn == *pinsns)
1237 else if (INSN_P (insn))
1240 && ! find_reg_note (insn, REG_EH_REGION, NULL_RTX)
1241 /* Calls can always potentially throw exceptions, unless
1242 they have a REG_EH_REGION note with a value of 0 or less.
1243 Which should be the only possible kind so far. */
1244 && (GET_CODE (insn) == CALL_INSN
1245 /* If we wanted exceptions for non-call insns, then
1246 any may_trap_p instruction could throw. */
1247 || (flag_non_call_exceptions
1248 && GET_CODE (PATTERN (insn)) != CLOBBER
1249 && GET_CODE (PATTERN (insn)) != USE
1250 && may_trap_p (PATTERN (insn)))))
1252 REG_NOTES (insn) = alloc_EXPR_LIST (REG_EH_REGION, GEN_INT (cur),
1256 if (GET_CODE (insn) == CALL_INSN
1257 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
1259 convert_from_eh_region_ranges_1 (&XEXP (PATTERN (insn), 0),
1261 convert_from_eh_region_ranges_1 (&XEXP (PATTERN (insn), 1),
1263 convert_from_eh_region_ranges_1 (&XEXP (PATTERN (insn), 2),
1274 convert_from_eh_region_ranges ()
1279 collect_eh_region_array ();
1280 resolve_fixup_regions ();
1282 stack = xmalloc (sizeof (int) * (cfun->eh->last_region_number + 1));
1283 insns = get_insns ();
1284 convert_from_eh_region_ranges_1 (&insns, stack, 0);
1287 remove_fixup_regions ();
1291 find_exception_handler_labels ()
1293 rtx list = NULL_RTX;
1296 free_EXPR_LIST_list (&exception_handler_labels);
1298 if (cfun->eh->region_tree == NULL)
1301 for (i = cfun->eh->last_region_number; i > 0; --i)
1303 struct eh_region *region = cfun->eh->region_array[i];
1308 if (cfun->eh->built_landing_pads)
1309 lab = region->landing_pad;
1311 lab = region->label;
1314 list = alloc_EXPR_LIST (0, lab, list);
1317 /* For sjlj exceptions, need the return label to remain live until
1318 after landing pad generation. */
1319 if (USING_SJLJ_EXCEPTIONS && ! cfun->eh->built_landing_pads)
1320 list = alloc_EXPR_LIST (0, return_label, list);
1322 exception_handler_labels = list;
1326 static struct eh_region *
1327 duplicate_eh_region_1 (o, map)
1328 struct eh_region *o;
1329 struct inline_remap *map;
1332 = (struct eh_region *) xcalloc (1, sizeof (struct eh_region));
1334 n->region_number = o->region_number + cfun->eh->last_region_number;
1340 case ERT_MUST_NOT_THROW:
1344 if (o->u.try.continue_label)
1345 n->u.try.continue_label
1346 = get_label_from_map (map,
1347 CODE_LABEL_NUMBER (o->u.try.continue_label));
1351 n->u.catch.type = o->u.catch.type;
1354 case ERT_ALLOWED_EXCEPTIONS:
1355 n->u.allowed.type_list = o->u.allowed.type_list;
1359 n->u.throw.type = o->u.throw.type;
1366 n->label = get_label_from_map (map, CODE_LABEL_NUMBER (o->label));
1369 n->resume = map->insn_map[INSN_UID (o->resume)];
1370 if (n->resume == NULL)
1378 duplicate_eh_region_2 (o, n_array)
1379 struct eh_region *o;
1380 struct eh_region **n_array;
1382 struct eh_region *n = n_array[o->region_number];
1387 n->u.try.catch = n_array[o->u.try.catch->region_number];
1388 n->u.try.last_catch = n_array[o->u.try.last_catch->region_number];
1392 if (o->u.catch.next_catch)
1393 n->u.catch.next_catch = n_array[o->u.catch.next_catch->region_number];
1394 if (o->u.catch.prev_catch)
1395 n->u.catch.prev_catch = n_array[o->u.catch.prev_catch->region_number];
1403 n->outer = n_array[o->outer->region_number];
1405 n->inner = n_array[o->inner->region_number];
1407 n->next_peer = n_array[o->next_peer->region_number];
1411 duplicate_eh_regions (ifun, map)
1412 struct function *ifun;
1413 struct inline_remap *map;
1415 int ifun_last_region_number = ifun->eh->last_region_number;
1416 struct eh_region **n_array, *root, *cur;
1419 if (ifun_last_region_number == 0)
1422 n_array = xcalloc (ifun_last_region_number + 1, sizeof (*n_array));
1424 for (i = 1; i <= ifun_last_region_number; ++i)
1426 cur = ifun->eh->region_array[i];
1427 if (!cur || cur->region_number != i)
1429 n_array[i] = duplicate_eh_region_1 (cur, map);
1431 for (i = 1; i <= ifun_last_region_number; ++i)
1433 cur = ifun->eh->region_array[i];
1434 if (!cur || cur->region_number != i)
1436 duplicate_eh_region_2 (cur, n_array);
1439 root = n_array[ifun->eh->region_tree->region_number];
1440 cur = cfun->eh->cur_region;
1443 struct eh_region *p = cur->inner;
1446 while (p->next_peer)
1448 p->next_peer = root;
1453 for (i = 1; i <= ifun_last_region_number; ++i)
1454 if (n_array[i] && n_array[i]->outer == NULL)
1455 n_array[i]->outer = cur;
1459 struct eh_region *p = cfun->eh->region_tree;
1462 while (p->next_peer)
1464 p->next_peer = root;
1467 cfun->eh->region_tree = root;
1472 i = cfun->eh->last_region_number;
1473 cfun->eh->last_region_number = i + ifun_last_region_number;
1478 /* ??? Move from tree.c to tree.h. */
1479 #define TYPE_HASH(TYPE) ((size_t) (TYPE) & 0777777)
1482 t2r_eq (pentry, pdata)
1486 tree entry = (tree) pentry;
1487 tree data = (tree) pdata;
1489 return TREE_PURPOSE (entry) == data;
1496 tree entry = (tree) pentry;
1497 return TYPE_HASH (TREE_PURPOSE (entry));
1501 t2r_mark_1 (slot, data)
1503 PTR data ATTRIBUTE_UNUSED;
1505 tree contents = (tree) *slot;
1506 ggc_mark_tree (contents);
1514 htab_traverse (*(htab_t *)addr, t2r_mark_1, NULL);
1518 add_type_for_runtime (type)
1523 slot = (tree *) htab_find_slot_with_hash (type_to_runtime_map, type,
1524 TYPE_HASH (type), INSERT);
1527 tree runtime = (*lang_eh_runtime_type) (type);
1528 *slot = tree_cons (type, runtime, NULL_TREE);
1533 lookup_type_for_runtime (type)
1538 slot = (tree *) htab_find_slot_with_hash (type_to_runtime_map, type,
1539 TYPE_HASH (type), NO_INSERT);
1541 /* We should have always inserrted the data earlier. */
1542 return TREE_VALUE (*slot);
1546 /* Represent an entry in @TTypes for either catch actions
1547 or exception filter actions. */
1548 struct ttypes_filter
1554 /* Compare ENTRY (a ttypes_filter entry in the hash table) with DATA
1555 (a tree) for a @TTypes type node we are thinking about adding. */
1558 ttypes_filter_eq (pentry, pdata)
1562 const struct ttypes_filter *entry = (const struct ttypes_filter *) pentry;
1563 tree data = (tree) pdata;
1565 return entry->t == data;
1569 ttypes_filter_hash (pentry)
1572 const struct ttypes_filter *entry = (const struct ttypes_filter *) pentry;
1573 return TYPE_HASH (entry->t);
1576 /* Compare ENTRY with DATA (both struct ttypes_filter) for a @TTypes
1577 exception specification list we are thinking about adding. */
1578 /* ??? Currently we use the type lists in the order given. Someone
1579 should put these in some canonical order. */
1582 ehspec_filter_eq (pentry, pdata)
1586 const struct ttypes_filter *entry = (const struct ttypes_filter *) pentry;
1587 const struct ttypes_filter *data = (const struct ttypes_filter *) pdata;
1589 return type_list_equal (entry->t, data->t);
1592 /* Hash function for exception specification lists. */
1595 ehspec_filter_hash (pentry)
1598 const struct ttypes_filter *entry = (const struct ttypes_filter *) pentry;
1602 for (list = entry->t; list ; list = TREE_CHAIN (list))
1603 h = (h << 5) + (h >> 27) + TYPE_HASH (TREE_VALUE (list));
1607 /* Add TYPE to cfun->eh->ttype_data, using TYPES_HASH to speed
1608 up the search. Return the filter value to be used. */
1611 add_ttypes_entry (ttypes_hash, type)
1615 struct ttypes_filter **slot, *n;
1617 slot = (struct ttypes_filter **)
1618 htab_find_slot_with_hash (ttypes_hash, type, TYPE_HASH (type), INSERT);
1620 if ((n = *slot) == NULL)
1622 /* Filter value is a 1 based table index. */
1624 n = (struct ttypes_filter *) xmalloc (sizeof (*n));
1626 n->filter = VARRAY_ACTIVE_SIZE (cfun->eh->ttype_data) + 1;
1629 VARRAY_PUSH_TREE (cfun->eh->ttype_data, type);
1635 /* Add LIST to cfun->eh->ehspec_data, using EHSPEC_HASH and TYPES_HASH
1636 to speed up the search. Return the filter value to be used. */
1639 add_ehspec_entry (ehspec_hash, ttypes_hash, list)
1644 struct ttypes_filter **slot, *n;
1645 struct ttypes_filter dummy;
1648 slot = (struct ttypes_filter **)
1649 htab_find_slot (ehspec_hash, &dummy, INSERT);
1651 if ((n = *slot) == NULL)
1653 /* Filter value is a -1 based byte index into a uleb128 buffer. */
1655 n = (struct ttypes_filter *) xmalloc (sizeof (*n));
1657 n->filter = -(VARRAY_ACTIVE_SIZE (cfun->eh->ehspec_data) + 1);
1660 /* Look up each type in the list and encode its filter
1661 value as a uleb128. Terminate the list with 0. */
1662 for (; list ; list = TREE_CHAIN (list))
1663 push_uleb128 (&cfun->eh->ehspec_data,
1664 add_ttypes_entry (ttypes_hash, TREE_VALUE (list)));
1665 VARRAY_PUSH_UCHAR (cfun->eh->ehspec_data, 0);
1671 /* Generate the action filter values to be used for CATCH and
1672 ALLOWED_EXCEPTIONS regions. When using dwarf2 exception regions,
1673 we use lots of landing pads, and so every type or list can share
1674 the same filter value, which saves table space. */
1677 assign_filter_values ()
1680 htab_t ttypes, ehspec;
1682 VARRAY_TREE_INIT (cfun->eh->ttype_data, 16, "ttype_data");
1683 VARRAY_UCHAR_INIT (cfun->eh->ehspec_data, 64, "ehspec_data");
1685 ttypes = htab_create (31, ttypes_filter_hash, ttypes_filter_eq, free);
1686 ehspec = htab_create (31, ehspec_filter_hash, ehspec_filter_eq, free);
1688 for (i = cfun->eh->last_region_number; i > 0; --i)
1690 struct eh_region *r = cfun->eh->region_array[i];
1692 /* Mind we don't process a region more than once. */
1693 if (!r || r->region_number != i)
1699 r->u.catch.filter = add_ttypes_entry (ttypes, r->u.catch.type);
1702 case ERT_ALLOWED_EXCEPTIONS:
1704 = add_ehspec_entry (ehspec, ttypes, r->u.allowed.type_list);
1712 htab_delete (ttypes);
1713 htab_delete (ehspec);
1717 build_post_landing_pads ()
1721 for (i = cfun->eh->last_region_number; i > 0; --i)
1723 struct eh_region *region = cfun->eh->region_array[i];
1726 /* Mind we don't process a region more than once. */
1727 if (!region || region->region_number != i)
1730 switch (region->type)
1733 /* ??? Collect the set of all non-overlapping catch handlers
1734 all the way up the chain until blocked by a cleanup. */
1735 /* ??? Outer try regions can share landing pads with inner
1736 try regions if the types are completely non-overlapping,
1737 and there are no interveaning cleanups. */
1739 region->post_landing_pad = gen_label_rtx ();
1743 emit_label (region->post_landing_pad);
1745 /* ??? It is mighty inconvenient to call back into the
1746 switch statement generation code in expand_end_case.
1747 Rapid prototyping sez a sequence of ifs. */
1749 struct eh_region *c;
1750 for (c = region->u.try.catch; c ; c = c->u.catch.next_catch)
1752 /* ??? _Unwind_ForcedUnwind wants no match here. */
1753 if (c->u.catch.type == NULL)
1754 emit_jump (c->label);
1756 emit_cmp_and_jump_insns (cfun->eh->filter,
1757 GEN_INT (c->u.catch.filter),
1758 EQ, NULL_RTX, word_mode,
1763 /* We delay the generation of the _Unwind_Resume until we generate
1764 landing pads. We emit a marker here so as to get good control
1765 flow data in the meantime. */
1767 = emit_jump_insn (gen_rtx_RESX (VOIDmode, region->region_number));
1773 emit_insns_before (seq, region->u.try.catch->label);
1776 case ERT_ALLOWED_EXCEPTIONS:
1777 region->post_landing_pad = gen_label_rtx ();
1781 emit_label (region->post_landing_pad);
1783 emit_cmp_and_jump_insns (cfun->eh->filter,
1784 GEN_INT (region->u.allowed.filter),
1785 EQ, NULL_RTX, word_mode, 0, 0,
1788 /* We delay the generation of the _Unwind_Resume until we generate
1789 landing pads. We emit a marker here so as to get good control
1790 flow data in the meantime. */
1792 = emit_jump_insn (gen_rtx_RESX (VOIDmode, region->region_number));
1798 emit_insns_before (seq, region->label);
1802 case ERT_MUST_NOT_THROW:
1803 region->post_landing_pad = region->label;
1808 /* Nothing to do. */
1817 /* Replace RESX patterns with jumps to the next handler if any, or calls to
1818 _Unwind_Resume otherwise. */
1821 connect_post_landing_pads ()
1825 for (i = cfun->eh->last_region_number; i > 0; --i)
1827 struct eh_region *region = cfun->eh->region_array[i];
1828 struct eh_region *outer;
1831 /* Mind we don't process a region more than once. */
1832 if (!region || region->region_number != i)
1835 /* If there is no RESX, or it has been deleted by flow, there's
1836 nothing to fix up. */
1837 if (! region->resume || INSN_DELETED_P (region->resume))
1840 /* Search for another landing pad in this function. */
1841 for (outer = region->outer; outer ; outer = outer->outer)
1842 if (outer->post_landing_pad)
1848 emit_jump (outer->post_landing_pad);
1850 emit_library_call (unwind_resume_libfunc, LCT_THROW,
1851 VOIDmode, 1, cfun->eh->exc_ptr, Pmode);
1855 emit_insns_before (seq, region->resume);
1856 flow_delete_insn (region->resume);
1862 dw2_build_landing_pads ()
1867 for (i = cfun->eh->last_region_number; i > 0; --i)
1869 struct eh_region *region = cfun->eh->region_array[i];
1872 /* Mind we don't process a region more than once. */
1873 if (!region || region->region_number != i)
1876 if (region->type != ERT_CLEANUP
1877 && region->type != ERT_TRY
1878 && region->type != ERT_ALLOWED_EXCEPTIONS)
1883 region->landing_pad = gen_label_rtx ();
1884 emit_label (region->landing_pad);
1886 #ifdef HAVE_exception_receiver
1887 if (HAVE_exception_receiver)
1888 emit_insn (gen_exception_receiver ());
1891 #ifdef HAVE_nonlocal_goto_receiver
1892 if (HAVE_nonlocal_goto_receiver)
1893 emit_insn (gen_nonlocal_goto_receiver ());
1898 /* If the eh_return data registers are call-saved, then we
1899 won't have considered them clobbered from the call that
1900 threw. Kill them now. */
1903 unsigned r = EH_RETURN_DATA_REGNO (j);
1904 if (r == INVALID_REGNUM)
1906 if (! call_used_regs[r])
1907 emit_insn (gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (Pmode, r)));
1910 emit_move_insn (cfun->eh->exc_ptr,
1911 gen_rtx_REG (Pmode, EH_RETURN_DATA_REGNO (0)));
1912 emit_move_insn (cfun->eh->filter,
1913 gen_rtx_REG (word_mode, EH_RETURN_DATA_REGNO (1)));
1918 emit_insns_before (seq, region->post_landing_pad);
1925 int directly_reachable;
1928 int call_site_index;
1932 sjlj_find_directly_reachable_regions (lp_info)
1933 struct sjlj_lp_info *lp_info;
1936 bool found_one = false;
1938 for (insn = get_insns (); insn ; insn = NEXT_INSN (insn))
1940 struct eh_region *region;
1944 if (! INSN_P (insn))
1947 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1948 if (!note || INTVAL (XEXP (note, 0)) <= 0)
1951 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
1953 type_thrown = NULL_TREE;
1954 if (region->type == ERT_THROW)
1956 type_thrown = region->u.throw.type;
1957 region = region->outer;
1960 /* Find the first containing region that might handle the exception.
1961 That's the landing pad to which we will transfer control. */
1962 for (; region; region = region->outer)
1963 if (reachable_next_level (region, type_thrown, 0) != RNL_NOT_CAUGHT)
1968 lp_info[region->region_number].directly_reachable = 1;
1977 sjlj_assign_call_site_values (dispatch_label, lp_info)
1979 struct sjlj_lp_info *lp_info;
1984 /* First task: build the action table. */
1986 VARRAY_UCHAR_INIT (cfun->eh->action_record_data, 64, "action_record_data");
1987 ar_hash = htab_create (31, action_record_hash, action_record_eq, free);
1989 for (i = cfun->eh->last_region_number; i > 0; --i)
1990 if (lp_info[i].directly_reachable)
1992 struct eh_region *r = cfun->eh->region_array[i];
1993 r->landing_pad = dispatch_label;
1994 lp_info[i].action_index = collect_one_action_chain (ar_hash, r);
1995 if (lp_info[i].action_index != -1)
1996 cfun->uses_eh_lsda = 1;
1999 htab_delete (ar_hash);
2001 /* Next: assign dispatch values. In dwarf2 terms, this would be the
2002 landing pad label for the region. For sjlj though, there is one
2003 common landing pad from which we dispatch to the post-landing pads.
2005 A region receives a dispatch index if it is directly reachable
2006 and requires in-function processing. Regions that share post-landing
2007 pads may share dispatch indicies. */
2008 /* ??? Post-landing pad sharing doesn't actually happen at the moment
2009 (see build_post_landing_pads) so we don't bother checking for it. */
2012 for (i = cfun->eh->last_region_number; i > 0; --i)
2013 if (lp_info[i].directly_reachable
2014 && lp_info[i].action_index >= 0)
2015 lp_info[i].dispatch_index = index++;
2017 /* Finally: assign call-site values. If dwarf2 terms, this would be
2018 the region number assigned by convert_to_eh_region_ranges, but
2019 handles no-action and must-not-throw differently. */
2022 for (i = cfun->eh->last_region_number; i > 0; --i)
2023 if (lp_info[i].directly_reachable)
2025 int action = lp_info[i].action_index;
2027 /* Map must-not-throw to otherwise unused call-site index 0. */
2030 /* Map no-action to otherwise unused call-site index -1. */
2031 else if (action == -1)
2033 /* Otherwise, look it up in the table. */
2035 index = add_call_site (GEN_INT (lp_info[i].dispatch_index), action);
2037 lp_info[i].call_site_index = index;
2042 sjlj_mark_call_sites (lp_info)
2043 struct sjlj_lp_info *lp_info;
2045 int last_call_site = -2;
2048 mem = adjust_address (cfun->eh->sjlj_fc, TYPE_MODE (integer_type_node),
2049 sjlj_fc_call_site_ofs);
2051 for (insn = get_insns (); insn ; insn = NEXT_INSN (insn))
2053 struct eh_region *region;
2055 rtx note, before, p;
2057 /* Reset value tracking at extended basic block boundaries. */
2058 if (GET_CODE (insn) == CODE_LABEL)
2059 last_call_site = -2;
2061 if (! INSN_P (insn))
2064 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
2067 /* Calls (and trapping insns) without notes are outside any
2068 exception handling region in this function. Mark them as
2070 if (GET_CODE (insn) == CALL_INSN
2071 || (flag_non_call_exceptions
2072 && may_trap_p (PATTERN (insn))))
2073 this_call_site = -1;
2079 /* Calls that are known to not throw need not be marked. */
2080 if (INTVAL (XEXP (note, 0)) <= 0)
2083 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
2084 this_call_site = lp_info[region->region_number].call_site_index;
2087 if (this_call_site == last_call_site)
2090 /* Don't separate a call from it's argument loads. */
2092 if (GET_CODE (insn) == CALL_INSN)
2093 before = find_first_parameter_load (insn, NULL_RTX);
2096 emit_move_insn (mem, GEN_INT (this_call_site));
2100 emit_insns_before (p, before);
2101 last_call_site = this_call_site;
2105 /* Construct the SjLj_Function_Context. */
2108 sjlj_emit_function_enter (dispatch_label)
2111 rtx fn_begin, fc, mem, seq;
2113 fc = cfun->eh->sjlj_fc;
2117 /* We're storing this libcall's address into memory instead of
2118 calling it directly. Thus, we must call assemble_external_libcall
2119 here, as we can not depend on emit_library_call to do it for us. */
2120 assemble_external_libcall (eh_personality_libfunc);
2121 mem = adjust_address (fc, Pmode, sjlj_fc_personality_ofs);
2122 emit_move_insn (mem, eh_personality_libfunc);
2124 mem = adjust_address (fc, Pmode, sjlj_fc_lsda_ofs);
2125 if (cfun->uses_eh_lsda)
2128 ASM_GENERATE_INTERNAL_LABEL (buf, "LLSDA", sjlj_funcdef_number);
2129 emit_move_insn (mem, gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (buf)));
2132 emit_move_insn (mem, const0_rtx);
2134 #ifdef DONT_USE_BUILTIN_SETJMP
2137 x = emit_library_call_value (setjmp_libfunc, NULL_RTX, LCT_NORMAL,
2138 TYPE_MODE (integer_type_node), 1,
2139 plus_constant (XEXP (fc, 0),
2140 sjlj_fc_jbuf_ofs), Pmode);
2142 note = emit_note (NULL, NOTE_INSN_EXPECTED_VALUE);
2143 NOTE_EXPECTED_VALUE (note) = gen_rtx_EQ (VOIDmode, x, const0_rtx);
2145 emit_cmp_and_jump_insns (x, const0_rtx, NE, 0,
2146 TYPE_MODE (integer_type_node), 0, 0,
2150 expand_builtin_setjmp_setup (plus_constant (XEXP (fc, 0), sjlj_fc_jbuf_ofs),
2154 emit_library_call (unwind_sjlj_register_libfunc, LCT_NORMAL, VOIDmode,
2155 1, XEXP (fc, 0), Pmode);
2160 /* ??? Instead of doing this at the beginning of the function,
2161 do this in a block that is at loop level 0 and dominates all
2162 can_throw_internal instructions. */
2164 for (fn_begin = get_insns (); ; fn_begin = NEXT_INSN (fn_begin))
2165 if (GET_CODE (fn_begin) == NOTE
2166 && NOTE_LINE_NUMBER (fn_begin) == NOTE_INSN_FUNCTION_BEG)
2168 emit_insns_after (seq, fn_begin);
2171 /* Call back from expand_function_end to know where we should put
2172 the call to unwind_sjlj_unregister_libfunc if needed. */
2175 sjlj_emit_function_exit_after (after)
2178 cfun->eh->sjlj_exit_after = after;
2182 sjlj_emit_function_exit ()
2188 emit_library_call (unwind_sjlj_unregister_libfunc, LCT_NORMAL, VOIDmode,
2189 1, XEXP (cfun->eh->sjlj_fc, 0), Pmode);
2194 /* ??? Really this can be done in any block at loop level 0 that
2195 post-dominates all can_throw_internal instructions. This is
2196 the last possible moment. */
2198 emit_insns_after (seq, cfun->eh->sjlj_exit_after);
2202 sjlj_emit_dispatch_table (dispatch_label, lp_info)
2204 struct sjlj_lp_info *lp_info;
2206 int i, first_reachable;
2207 rtx mem, dispatch, seq, fc;
2209 fc = cfun->eh->sjlj_fc;
2213 emit_label (dispatch_label);
2215 #ifndef DONT_USE_BUILTIN_SETJMP
2216 expand_builtin_setjmp_receiver (dispatch_label);
2219 /* Load up dispatch index, exc_ptr and filter values from the
2220 function context. */
2221 mem = adjust_address (fc, TYPE_MODE (integer_type_node),
2222 sjlj_fc_call_site_ofs);
2223 dispatch = copy_to_reg (mem);
2225 mem = adjust_address (fc, word_mode, sjlj_fc_data_ofs);
2226 if (word_mode != Pmode)
2228 #ifdef POINTERS_EXTEND_UNSIGNED
2229 mem = convert_memory_address (Pmode, mem);
2231 mem = convert_to_mode (Pmode, mem, 0);
2234 emit_move_insn (cfun->eh->exc_ptr, mem);
2236 mem = adjust_address (fc, word_mode, sjlj_fc_data_ofs + UNITS_PER_WORD);
2237 emit_move_insn (cfun->eh->filter, mem);
2239 /* Jump to one of the directly reachable regions. */
2240 /* ??? This really ought to be using a switch statement. */
2242 first_reachable = 0;
2243 for (i = cfun->eh->last_region_number; i > 0; --i)
2245 if (! lp_info[i].directly_reachable
2246 || lp_info[i].action_index < 0)
2249 if (! first_reachable)
2251 first_reachable = i;
2255 emit_cmp_and_jump_insns (dispatch,
2256 GEN_INT (lp_info[i].dispatch_index), EQ,
2257 NULL_RTX, TYPE_MODE (integer_type_node), 0, 0,
2258 cfun->eh->region_array[i]->post_landing_pad);
2264 emit_insns_before (seq, (cfun->eh->region_array[first_reachable]
2265 ->post_landing_pad));
2269 sjlj_build_landing_pads ()
2271 struct sjlj_lp_info *lp_info;
2273 lp_info = (struct sjlj_lp_info *) xcalloc (cfun->eh->last_region_number + 1,
2274 sizeof (struct sjlj_lp_info));
2276 if (sjlj_find_directly_reachable_regions (lp_info))
2278 rtx dispatch_label = gen_label_rtx ();
2281 = assign_stack_local (TYPE_MODE (sjlj_fc_type_node),
2282 int_size_in_bytes (sjlj_fc_type_node),
2283 TYPE_ALIGN (sjlj_fc_type_node));
2285 sjlj_assign_call_site_values (dispatch_label, lp_info);
2286 sjlj_mark_call_sites (lp_info);
2288 sjlj_emit_function_enter (dispatch_label);
2289 sjlj_emit_dispatch_table (dispatch_label, lp_info);
2290 sjlj_emit_function_exit ();
2297 finish_eh_generation ()
2299 /* Nothing to do if no regions created. */
2300 if (cfun->eh->region_tree == NULL)
2303 /* The object here is to provide find_basic_blocks with detailed
2304 information (via reachable_handlers) on how exception control
2305 flows within the function. In this first pass, we can include
2306 type information garnered from ERT_THROW and ERT_ALLOWED_EXCEPTIONS
2307 regions, and hope that it will be useful in deleting unreachable
2308 handlers. Subsequently, we will generate landing pads which will
2309 connect many of the handlers, and then type information will not
2310 be effective. Still, this is a win over previous implementations. */
2312 rebuild_jump_labels (get_insns ());
2313 find_basic_blocks (get_insns (), max_reg_num (), 0);
2314 cleanup_cfg (CLEANUP_PRE_LOOP);
2316 /* These registers are used by the landing pads. Make sure they
2317 have been generated. */
2318 get_exception_pointer (cfun);
2319 get_exception_filter (cfun);
2321 /* Construct the landing pads. */
2323 assign_filter_values ();
2324 build_post_landing_pads ();
2325 connect_post_landing_pads ();
2326 if (USING_SJLJ_EXCEPTIONS)
2327 sjlj_build_landing_pads ();
2329 dw2_build_landing_pads ();
2331 cfun->eh->built_landing_pads = 1;
2333 /* We've totally changed the CFG. Start over. */
2334 find_exception_handler_labels ();
2335 rebuild_jump_labels (get_insns ());
2336 find_basic_blocks (get_insns (), max_reg_num (), 0);
2337 cleanup_cfg (CLEANUP_PRE_LOOP);
2340 /* This section handles removing dead code for flow. */
2342 /* Remove LABEL from the exception_handler_labels list. */
2345 remove_exception_handler_label (label)
2350 for (pl = &exception_handler_labels, l = *pl;
2351 XEXP (l, 0) != label;
2352 pl = &XEXP (l, 1), l = *pl)
2356 free_EXPR_LIST_node (l);
2359 /* Splice REGION from the region tree etc. */
2362 remove_eh_handler (region)
2363 struct eh_region *region;
2365 struct eh_region **pp, *p;
2369 /* For the benefit of efficiently handling REG_EH_REGION notes,
2370 replace this region in the region array with its containing
2371 region. Note that previous region deletions may result in
2372 multiple copies of this region in the array, so we have to
2373 search the whole thing. */
2374 for (i = cfun->eh->last_region_number; i > 0; --i)
2375 if (cfun->eh->region_array[i] == region)
2376 cfun->eh->region_array[i] = region->outer;
2378 if (cfun->eh->built_landing_pads)
2379 lab = region->landing_pad;
2381 lab = region->label;
2383 remove_exception_handler_label (lab);
2386 pp = ®ion->outer->inner;
2388 pp = &cfun->eh->region_tree;
2389 for (p = *pp; p != region; pp = &p->next_peer, p = *pp)
2394 for (p = region->inner; p->next_peer ; p = p->next_peer)
2395 p->outer = region->outer;
2396 p->next_peer = region->next_peer;
2397 p->outer = region->outer;
2398 *pp = region->inner;
2401 *pp = region->next_peer;
2403 if (region->type == ERT_CATCH)
2405 struct eh_region *try, *next, *prev;
2407 for (try = region->next_peer;
2408 try->type == ERT_CATCH;
2409 try = try->next_peer)
2411 if (try->type != ERT_TRY)
2414 next = region->u.catch.next_catch;
2415 prev = region->u.catch.prev_catch;
2418 next->u.catch.prev_catch = prev;
2420 try->u.try.last_catch = prev;
2422 prev->u.catch.next_catch = next;
2425 try->u.try.catch = next;
2427 remove_eh_handler (try);
2434 /* LABEL heads a basic block that is about to be deleted. If this
2435 label corresponds to an exception region, we may be able to
2436 delete the region. */
2439 maybe_remove_eh_handler (label)
2444 /* ??? After generating landing pads, it's not so simple to determine
2445 if the region data is completely unused. One must examine the
2446 landing pad and the post landing pad, and whether an inner try block
2447 is referencing the catch handlers directly. */
2448 if (cfun->eh->built_landing_pads)
2451 for (i = cfun->eh->last_region_number; i > 0; --i)
2453 struct eh_region *region = cfun->eh->region_array[i];
2454 if (region && region->label == label)
2456 /* Flow will want to remove MUST_NOT_THROW regions as unreachable
2457 because there is no path to the fallback call to terminate.
2458 But the region continues to affect call-site data until there
2459 are no more contained calls, which we don't see here. */
2460 if (region->type == ERT_MUST_NOT_THROW)
2462 remove_exception_handler_label (region->label);
2463 region->label = NULL_RTX;
2466 remove_eh_handler (region);
2473 /* This section describes CFG exception edges for flow. */
2475 /* For communicating between calls to reachable_next_level. */
2476 struct reachable_info
2483 /* A subroutine of reachable_next_level. Return true if TYPE, or a
2484 base class of TYPE, is in HANDLED. */
2487 check_handled (handled, type)
2492 /* We can check for exact matches without front-end help. */
2493 if (! lang_eh_type_covers)
2495 for (t = handled; t ; t = TREE_CHAIN (t))
2496 if (TREE_VALUE (t) == type)
2501 for (t = handled; t ; t = TREE_CHAIN (t))
2502 if ((*lang_eh_type_covers) (TREE_VALUE (t), type))
2509 /* A subroutine of reachable_next_level. If we are collecting a list
2510 of handlers, add one. After landing pad generation, reference
2511 it instead of the handlers themselves. Further, the handlers are
2512 all wired together, so by referencing one, we've got them all.
2513 Before landing pad generation we reference each handler individually.
2515 LP_REGION contains the landing pad; REGION is the handler. */
2518 add_reachable_handler (info, lp_region, region)
2519 struct reachable_info *info;
2520 struct eh_region *lp_region;
2521 struct eh_region *region;
2526 if (cfun->eh->built_landing_pads)
2528 if (! info->handlers)
2529 info->handlers = alloc_INSN_LIST (lp_region->landing_pad, NULL_RTX);
2532 info->handlers = alloc_INSN_LIST (region->label, info->handlers);
2535 /* Process one level of exception regions for reachability.
2536 If TYPE_THROWN is non-null, then it is the *exact* type being
2537 propagated. If INFO is non-null, then collect handler labels
2538 and caught/allowed type information between invocations. */
2540 static enum reachable_code
2541 reachable_next_level (region, type_thrown, info)
2542 struct eh_region *region;
2544 struct reachable_info *info;
2546 switch (region->type)
2549 /* Before landing-pad generation, we model control flow
2550 directly to the individual handlers. In this way we can
2551 see that catch handler types may shadow one another. */
2552 add_reachable_handler (info, region, region);
2553 return RNL_MAYBE_CAUGHT;
2557 struct eh_region *c;
2558 enum reachable_code ret = RNL_NOT_CAUGHT;
2560 for (c = region->u.try.catch; c ; c = c->u.catch.next_catch)
2562 /* A catch-all handler ends the search. */
2563 /* ??? _Unwind_ForcedUnwind will want outer cleanups
2564 to be run as well. */
2565 if (c->u.catch.type == NULL)
2567 add_reachable_handler (info, region, c);
2573 /* If we have a type match, end the search. */
2574 if (c->u.catch.type == type_thrown
2575 || (lang_eh_type_covers
2576 && (*lang_eh_type_covers) (c->u.catch.type,
2579 add_reachable_handler (info, region, c);
2583 /* If we have definitive information of a match failure,
2584 the catch won't trigger. */
2585 if (lang_eh_type_covers)
2586 return RNL_NOT_CAUGHT;
2590 ret = RNL_MAYBE_CAUGHT;
2592 /* A type must not have been previously caught. */
2593 else if (! check_handled (info->types_caught, c->u.catch.type))
2595 add_reachable_handler (info, region, c);
2596 info->types_caught = tree_cons (NULL, c->u.catch.type,
2597 info->types_caught);
2599 /* ??? If the catch type is a base class of every allowed
2600 type, then we know we can stop the search. */
2601 ret = RNL_MAYBE_CAUGHT;
2608 case ERT_ALLOWED_EXCEPTIONS:
2609 /* An empty list of types definitely ends the search. */
2610 if (region->u.allowed.type_list == NULL_TREE)
2612 add_reachable_handler (info, region, region);
2616 /* Collect a list of lists of allowed types for use in detecting
2617 when a catch may be transformed into a catch-all. */
2619 info->types_allowed = tree_cons (NULL_TREE,
2620 region->u.allowed.type_list,
2621 info->types_allowed);
2623 /* If we have definitive information about the type heirarchy,
2624 then we can tell if the thrown type will pass through the
2626 if (type_thrown && lang_eh_type_covers)
2628 if (check_handled (region->u.allowed.type_list, type_thrown))
2629 return RNL_NOT_CAUGHT;
2632 add_reachable_handler (info, region, region);
2637 add_reachable_handler (info, region, region);
2638 return RNL_MAYBE_CAUGHT;
2641 /* Catch regions are handled by their controling try region. */
2642 return RNL_NOT_CAUGHT;
2644 case ERT_MUST_NOT_THROW:
2645 /* Here we end our search, since no exceptions may propagate.
2646 If we've touched down at some landing pad previous, then the
2647 explicit function call we generated may be used. Otherwise
2648 the call is made by the runtime. */
2649 if (info && info->handlers)
2651 add_reachable_handler (info, region, region);
2659 /* Shouldn't see these here. */
2666 /* Retrieve a list of labels of exception handlers which can be
2667 reached by a given insn. */
2670 reachable_handlers (insn)
2673 struct reachable_info info;
2674 struct eh_region *region;
2678 if (GET_CODE (insn) == JUMP_INSN
2679 && GET_CODE (PATTERN (insn)) == RESX)
2680 region_number = XINT (PATTERN (insn), 0);
2683 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
2684 if (!note || INTVAL (XEXP (note, 0)) <= 0)
2686 region_number = INTVAL (XEXP (note, 0));
2689 memset (&info, 0, sizeof (info));
2691 region = cfun->eh->region_array[region_number];
2693 type_thrown = NULL_TREE;
2694 if (GET_CODE (insn) == JUMP_INSN
2695 && GET_CODE (PATTERN (insn)) == RESX)
2697 /* A RESX leaves a region instead of entering it. Thus the
2698 region itself may have been deleted out from under us. */
2701 region = region->outer;
2703 else if (region->type == ERT_THROW)
2705 type_thrown = region->u.throw.type;
2706 region = region->outer;
2709 for (; region; region = region->outer)
2710 if (reachable_next_level (region, type_thrown, &info) >= RNL_CAUGHT)
2713 return info.handlers;
2716 /* Determine if the given INSN can throw an exception that is caught
2717 within the function. */
2720 can_throw_internal (insn)
2723 struct eh_region *region;
2727 if (! INSN_P (insn))
2730 if (GET_CODE (insn) == INSN
2731 && GET_CODE (PATTERN (insn)) == SEQUENCE)
2732 insn = XVECEXP (PATTERN (insn), 0, 0);
2734 if (GET_CODE (insn) == CALL_INSN
2735 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
2738 for (i = 0; i < 3; ++i)
2740 rtx sub = XEXP (PATTERN (insn), i);
2741 for (; sub ; sub = NEXT_INSN (sub))
2742 if (can_throw_internal (sub))
2748 /* Every insn that might throw has an EH_REGION note. */
2749 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
2750 if (!note || INTVAL (XEXP (note, 0)) <= 0)
2753 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
2755 type_thrown = NULL_TREE;
2756 if (region->type == ERT_THROW)
2758 type_thrown = region->u.throw.type;
2759 region = region->outer;
2762 /* If this exception is ignored by each and every containing region,
2763 then control passes straight out. The runtime may handle some
2764 regions, which also do not require processing internally. */
2765 for (; region; region = region->outer)
2767 enum reachable_code how = reachable_next_level (region, type_thrown, 0);
2768 if (how == RNL_BLOCKED)
2770 if (how != RNL_NOT_CAUGHT)
2777 /* Determine if the given INSN can throw an exception that is
2778 visible outside the function. */
2781 can_throw_external (insn)
2784 struct eh_region *region;
2788 if (! INSN_P (insn))
2791 if (GET_CODE (insn) == INSN
2792 && GET_CODE (PATTERN (insn)) == SEQUENCE)
2793 insn = XVECEXP (PATTERN (insn), 0, 0);
2795 if (GET_CODE (insn) == CALL_INSN
2796 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
2799 for (i = 0; i < 3; ++i)
2801 rtx sub = XEXP (PATTERN (insn), i);
2802 for (; sub ; sub = NEXT_INSN (sub))
2803 if (can_throw_external (sub))
2809 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
2812 /* Calls (and trapping insns) without notes are outside any
2813 exception handling region in this function. We have to
2814 assume it might throw. Given that the front end and middle
2815 ends mark known NOTHROW functions, this isn't so wildly
2817 return (GET_CODE (insn) == CALL_INSN
2818 || (flag_non_call_exceptions
2819 && may_trap_p (PATTERN (insn))));
2821 if (INTVAL (XEXP (note, 0)) <= 0)
2824 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
2826 type_thrown = NULL_TREE;
2827 if (region->type == ERT_THROW)
2829 type_thrown = region->u.throw.type;
2830 region = region->outer;
2833 /* If the exception is caught or blocked by any containing region,
2834 then it is not seen by any calling function. */
2835 for (; region ; region = region->outer)
2836 if (reachable_next_level (region, type_thrown, NULL) >= RNL_CAUGHT)
2842 /* True if nothing in this function can throw outside this function. */
2845 nothrow_function_p ()
2849 if (! flag_exceptions)
2852 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2853 if (can_throw_external (insn))
2855 for (insn = current_function_epilogue_delay_list; insn;
2856 insn = XEXP (insn, 1))
2857 if (can_throw_external (insn))
2864 /* Various hooks for unwind library. */
2866 /* Do any necessary initialization to access arbitrary stack frames.
2867 On the SPARC, this means flushing the register windows. */
2870 expand_builtin_unwind_init ()
2872 /* Set this so all the registers get saved in our frame; we need to be
2873 able to copy the saved values for any registers from frames we unwind. */
2874 current_function_has_nonlocal_label = 1;
2876 #ifdef SETUP_FRAME_ADDRESSES
2877 SETUP_FRAME_ADDRESSES ();
2882 expand_builtin_eh_return_data_regno (arglist)
2885 tree which = TREE_VALUE (arglist);
2886 unsigned HOST_WIDE_INT iwhich;
2888 if (TREE_CODE (which) != INTEGER_CST)
2890 error ("argument of `__builtin_eh_return_regno' must be constant");
2894 iwhich = tree_low_cst (which, 1);
2895 iwhich = EH_RETURN_DATA_REGNO (iwhich);
2896 if (iwhich == INVALID_REGNUM)
2899 #ifdef DWARF_FRAME_REGNUM
2900 iwhich = DWARF_FRAME_REGNUM (iwhich);
2902 iwhich = DBX_REGISTER_NUMBER (iwhich);
2905 return GEN_INT (iwhich);
2908 /* Given a value extracted from the return address register or stack slot,
2909 return the actual address encoded in that value. */
2912 expand_builtin_extract_return_addr (addr_tree)
2915 rtx addr = expand_expr (addr_tree, NULL_RTX, Pmode, 0);
2917 /* First mask out any unwanted bits. */
2918 #ifdef MASK_RETURN_ADDR
2919 expand_and (addr, MASK_RETURN_ADDR, addr);
2922 /* Then adjust to find the real return address. */
2923 #if defined (RETURN_ADDR_OFFSET)
2924 addr = plus_constant (addr, RETURN_ADDR_OFFSET);
2930 /* Given an actual address in addr_tree, do any necessary encoding
2931 and return the value to be stored in the return address register or
2932 stack slot so the epilogue will return to that address. */
2935 expand_builtin_frob_return_addr (addr_tree)
2938 rtx addr = expand_expr (addr_tree, NULL_RTX, Pmode, 0);
2940 #ifdef POINTERS_EXTEND_UNSIGNED
2941 addr = convert_memory_address (Pmode, addr);
2944 #ifdef RETURN_ADDR_OFFSET
2945 addr = force_reg (Pmode, addr);
2946 addr = plus_constant (addr, -RETURN_ADDR_OFFSET);
2952 /* Set up the epilogue with the magic bits we'll need to return to the
2953 exception handler. */
2956 expand_builtin_eh_return (stackadj_tree, handler_tree)
2957 tree stackadj_tree, handler_tree;
2959 rtx stackadj, handler;
2961 stackadj = expand_expr (stackadj_tree, cfun->eh->ehr_stackadj, VOIDmode, 0);
2962 handler = expand_expr (handler_tree, cfun->eh->ehr_handler, VOIDmode, 0);
2964 #ifdef POINTERS_EXTEND_UNSIGNED
2965 stackadj = convert_memory_address (Pmode, stackadj);
2966 handler = convert_memory_address (Pmode, handler);
2969 if (! cfun->eh->ehr_label)
2971 cfun->eh->ehr_stackadj = copy_to_reg (stackadj);
2972 cfun->eh->ehr_handler = copy_to_reg (handler);
2973 cfun->eh->ehr_label = gen_label_rtx ();
2977 if (stackadj != cfun->eh->ehr_stackadj)
2978 emit_move_insn (cfun->eh->ehr_stackadj, stackadj);
2979 if (handler != cfun->eh->ehr_handler)
2980 emit_move_insn (cfun->eh->ehr_handler, handler);
2983 emit_jump (cfun->eh->ehr_label);
2989 rtx sa, ra, around_label;
2991 if (! cfun->eh->ehr_label)
2994 sa = EH_RETURN_STACKADJ_RTX;
2997 error ("__builtin_eh_return not supported on this target");
3001 current_function_calls_eh_return = 1;
3003 around_label = gen_label_rtx ();
3004 emit_move_insn (sa, const0_rtx);
3005 emit_jump (around_label);
3007 emit_label (cfun->eh->ehr_label);
3008 clobber_return_register ();
3010 #ifdef HAVE_eh_return
3012 emit_insn (gen_eh_return (cfun->eh->ehr_stackadj, cfun->eh->ehr_handler));
3016 ra = EH_RETURN_HANDLER_RTX;
3019 error ("__builtin_eh_return not supported on this target");
3020 ra = gen_reg_rtx (Pmode);
3023 emit_move_insn (sa, cfun->eh->ehr_stackadj);
3024 emit_move_insn (ra, cfun->eh->ehr_handler);
3027 emit_label (around_label);
3030 /* In the following functions, we represent entries in the action table
3031 as 1-based indicies. Special cases are:
3033 0: null action record, non-null landing pad; implies cleanups
3034 -1: null action record, null landing pad; implies no action
3035 -2: no call-site entry; implies must_not_throw
3036 -3: we have yet to process outer regions
3038 Further, no special cases apply to the "next" field of the record.
3039 For next, 0 means end of list. */
3041 struct action_record
3049 action_record_eq (pentry, pdata)
3053 const struct action_record *entry = (const struct action_record *) pentry;
3054 const struct action_record *data = (const struct action_record *) pdata;
3055 return entry->filter == data->filter && entry->next == data->next;
3059 action_record_hash (pentry)
3062 const struct action_record *entry = (const struct action_record *) pentry;
3063 return entry->next * 1009 + entry->filter;
3067 add_action_record (ar_hash, filter, next)
3071 struct action_record **slot, *new, tmp;
3073 tmp.filter = filter;
3075 slot = (struct action_record **) htab_find_slot (ar_hash, &tmp, INSERT);
3077 if ((new = *slot) == NULL)
3079 new = (struct action_record *) xmalloc (sizeof (*new));
3080 new->offset = VARRAY_ACTIVE_SIZE (cfun->eh->action_record_data) + 1;
3081 new->filter = filter;
3085 /* The filter value goes in untouched. The link to the next
3086 record is a "self-relative" byte offset, or zero to indicate
3087 that there is no next record. So convert the absolute 1 based
3088 indicies we've been carrying around into a displacement. */
3090 push_sleb128 (&cfun->eh->action_record_data, filter);
3092 next -= VARRAY_ACTIVE_SIZE (cfun->eh->action_record_data) + 1;
3093 push_sleb128 (&cfun->eh->action_record_data, next);
3100 collect_one_action_chain (ar_hash, region)
3102 struct eh_region *region;
3104 struct eh_region *c;
3107 /* If we've reached the top of the region chain, then we have
3108 no actions, and require no landing pad. */
3112 switch (region->type)
3115 /* A cleanup adds a zero filter to the beginning of the chain, but
3116 there are special cases to look out for. If there are *only*
3117 cleanups along a path, then it compresses to a zero action.
3118 Further, if there are multiple cleanups along a path, we only
3119 need to represent one of them, as that is enough to trigger
3120 entry to the landing pad at runtime. */
3121 next = collect_one_action_chain (ar_hash, region->outer);
3124 for (c = region->outer; c ; c = c->outer)
3125 if (c->type == ERT_CLEANUP)
3127 return add_action_record (ar_hash, 0, next);
3130 /* Process the associated catch regions in reverse order.
3131 If there's a catch-all handler, then we don't need to
3132 search outer regions. Use a magic -3 value to record
3133 that we havn't done the outer search. */
3135 for (c = region->u.try.last_catch; c ; c = c->u.catch.prev_catch)
3137 if (c->u.catch.type == NULL)
3138 next = add_action_record (ar_hash, c->u.catch.filter, 0);
3143 next = collect_one_action_chain (ar_hash, region->outer);
3145 /* If there is no next action, terminate the chain. */
3148 /* If all outer actions are cleanups or must_not_throw,
3149 we'll have no action record for it, since we had wanted
3150 to encode these states in the call-site record directly.
3151 Add a cleanup action to the chain to catch these. */
3153 next = add_action_record (ar_hash, 0, 0);
3155 next = add_action_record (ar_hash, c->u.catch.filter, next);
3160 case ERT_ALLOWED_EXCEPTIONS:
3161 /* An exception specification adds its filter to the
3162 beginning of the chain. */
3163 next = collect_one_action_chain (ar_hash, region->outer);
3164 return add_action_record (ar_hash, region->u.allowed.filter,
3165 next < 0 ? 0 : next);
3167 case ERT_MUST_NOT_THROW:
3168 /* A must-not-throw region with no inner handlers or cleanups
3169 requires no call-site entry. Note that this differs from
3170 the no handler or cleanup case in that we do require an lsda
3171 to be generated. Return a magic -2 value to record this. */
3176 /* CATCH regions are handled in TRY above. THROW regions are
3177 for optimization information only and produce no output. */
3178 return collect_one_action_chain (ar_hash, region->outer);
3186 add_call_site (landing_pad, action)
3190 struct call_site_record *data = cfun->eh->call_site_data;
3191 int used = cfun->eh->call_site_data_used;
3192 int size = cfun->eh->call_site_data_size;
3196 size = (size ? size * 2 : 64);
3197 data = (struct call_site_record *)
3198 xrealloc (data, sizeof (*data) * size);
3199 cfun->eh->call_site_data = data;
3200 cfun->eh->call_site_data_size = size;
3203 data[used].landing_pad = landing_pad;
3204 data[used].action = action;
3206 cfun->eh->call_site_data_used = used + 1;
3208 return used + call_site_base;
3211 /* Turn REG_EH_REGION notes back into NOTE_INSN_EH_REGION notes.
3212 The new note numbers will not refer to region numbers, but
3213 instead to call site entries. */
3216 convert_to_eh_region_ranges ()
3218 rtx insn, iter, note;
3220 int last_action = -3;
3221 rtx last_action_insn = NULL_RTX;
3222 rtx last_landing_pad = NULL_RTX;
3223 rtx first_no_action_insn = NULL_RTX;
3226 if (USING_SJLJ_EXCEPTIONS || cfun->eh->region_tree == NULL)
3229 VARRAY_UCHAR_INIT (cfun->eh->action_record_data, 64, "action_record_data");
3231 ar_hash = htab_create (31, action_record_hash, action_record_eq, free);
3233 for (iter = get_insns (); iter ; iter = NEXT_INSN (iter))
3236 struct eh_region *region;
3238 rtx this_landing_pad;
3241 if (GET_CODE (insn) == INSN
3242 && GET_CODE (PATTERN (insn)) == SEQUENCE)
3243 insn = XVECEXP (PATTERN (insn), 0, 0);
3245 note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
3248 if (! (GET_CODE (insn) == CALL_INSN
3249 || (flag_non_call_exceptions
3250 && may_trap_p (PATTERN (insn)))))
3257 if (INTVAL (XEXP (note, 0)) <= 0)
3259 region = cfun->eh->region_array[INTVAL (XEXP (note, 0))];
3260 this_action = collect_one_action_chain (ar_hash, region);
3263 /* Existence of catch handlers, or must-not-throw regions
3264 implies that an lsda is needed (even if empty). */
3265 if (this_action != -1)
3266 cfun->uses_eh_lsda = 1;
3268 /* Delay creation of region notes for no-action regions
3269 until we're sure that an lsda will be required. */
3270 else if (last_action == -3)
3272 first_no_action_insn = iter;
3276 /* Cleanups and handlers may share action chains but not
3277 landing pads. Collect the landing pad for this region. */
3278 if (this_action >= 0)
3280 struct eh_region *o;
3281 for (o = region; ! o->landing_pad ; o = o->outer)
3283 this_landing_pad = o->landing_pad;
3286 this_landing_pad = NULL_RTX;
3288 /* Differing actions or landing pads implies a change in call-site
3289 info, which implies some EH_REGION note should be emitted. */
3290 if (last_action != this_action
3291 || last_landing_pad != this_landing_pad)
3293 /* If we'd not seen a previous action (-3) or the previous
3294 action was must-not-throw (-2), then we do not need an
3296 if (last_action >= -1)
3298 /* If we delayed the creation of the begin, do it now. */
3299 if (first_no_action_insn)
3301 call_site = add_call_site (NULL_RTX, 0);
3302 note = emit_note_before (NOTE_INSN_EH_REGION_BEG,
3303 first_no_action_insn);
3304 NOTE_EH_HANDLER (note) = call_site;
3305 first_no_action_insn = NULL_RTX;
3308 note = emit_note_after (NOTE_INSN_EH_REGION_END,
3310 NOTE_EH_HANDLER (note) = call_site;
3313 /* If the new action is must-not-throw, then no region notes
3315 if (this_action >= -1)
3317 call_site = add_call_site (this_landing_pad,
3318 this_action < 0 ? 0 : this_action);
3319 note = emit_note_before (NOTE_INSN_EH_REGION_BEG, iter);
3320 NOTE_EH_HANDLER (note) = call_site;
3323 last_action = this_action;
3324 last_landing_pad = this_landing_pad;
3326 last_action_insn = iter;
3329 if (last_action >= -1 && ! first_no_action_insn)
3331 note = emit_note_after (NOTE_INSN_EH_REGION_END, last_action_insn);
3332 NOTE_EH_HANDLER (note) = call_site;
3335 htab_delete (ar_hash);
3340 push_uleb128 (data_area, value)
3341 varray_type *data_area;
3346 unsigned char byte = value & 0x7f;
3350 VARRAY_PUSH_UCHAR (*data_area, byte);
3356 push_sleb128 (data_area, value)
3357 varray_type *data_area;
3365 byte = value & 0x7f;
3367 more = ! ((value == 0 && (byte & 0x40) == 0)
3368 || (value == -1 && (byte & 0x40) != 0));
3371 VARRAY_PUSH_UCHAR (*data_area, byte);
3377 #ifndef HAVE_AS_LEB128
3379 dw2_size_of_call_site_table ()
3381 int n = cfun->eh->call_site_data_used;
3382 int size = n * (4 + 4 + 4);
3385 for (i = 0; i < n; ++i)
3387 struct call_site_record *cs = &cfun->eh->call_site_data[i];
3388 size += size_of_uleb128 (cs->action);
3395 sjlj_size_of_call_site_table ()
3397 int n = cfun->eh->call_site_data_used;
3401 for (i = 0; i < n; ++i)
3403 struct call_site_record *cs = &cfun->eh->call_site_data[i];
3404 size += size_of_uleb128 (INTVAL (cs->landing_pad));
3405 size += size_of_uleb128 (cs->action);
3413 dw2_output_call_site_table ()
3415 const char *function_start_lab
3416 = IDENTIFIER_POINTER (current_function_func_begin_label);
3417 int n = cfun->eh->call_site_data_used;
3420 for (i = 0; i < n; ++i)
3422 struct call_site_record *cs = &cfun->eh->call_site_data[i];
3423 char reg_start_lab[32];
3424 char reg_end_lab[32];
3425 char landing_pad_lab[32];
3427 ASM_GENERATE_INTERNAL_LABEL (reg_start_lab, "LEHB", call_site_base + i);
3428 ASM_GENERATE_INTERNAL_LABEL (reg_end_lab, "LEHE", call_site_base + i);
3430 if (cs->landing_pad)
3431 ASM_GENERATE_INTERNAL_LABEL (landing_pad_lab, "L",
3432 CODE_LABEL_NUMBER (cs->landing_pad));
3434 /* ??? Perhaps use insn length scaling if the assembler supports
3435 generic arithmetic. */
3436 /* ??? Perhaps use attr_length to choose data1 or data2 instead of
3437 data4 if the function is small enough. */
3438 #ifdef HAVE_AS_LEB128
3439 dw2_asm_output_delta_uleb128 (reg_start_lab, function_start_lab,
3440 "region %d start", i);
3441 dw2_asm_output_delta_uleb128 (reg_end_lab, reg_start_lab,
3443 if (cs->landing_pad)
3444 dw2_asm_output_delta_uleb128 (landing_pad_lab, function_start_lab,
3447 dw2_asm_output_data_uleb128 (0, "landing pad");
3449 dw2_asm_output_delta (4, reg_start_lab, function_start_lab,
3450 "region %d start", i);
3451 dw2_asm_output_delta (4, reg_end_lab, reg_start_lab, "length");
3452 if (cs->landing_pad)
3453 dw2_asm_output_delta (4, landing_pad_lab, function_start_lab,
3456 dw2_asm_output_data (4, 0, "landing pad");
3458 dw2_asm_output_data_uleb128 (cs->action, "action");
3461 call_site_base += n;
3465 sjlj_output_call_site_table ()
3467 int n = cfun->eh->call_site_data_used;
3470 for (i = 0; i < n; ++i)
3472 struct call_site_record *cs = &cfun->eh->call_site_data[i];
3474 dw2_asm_output_data_uleb128 (INTVAL (cs->landing_pad),
3475 "region %d landing pad", i);
3476 dw2_asm_output_data_uleb128 (cs->action, "action");
3479 call_site_base += n;
3483 output_function_exception_table ()
3485 int tt_format, cs_format, lp_format, i, n;
3486 #ifdef HAVE_AS_LEB128
3487 char ttype_label[32];
3488 char cs_after_size_label[32];
3489 char cs_end_label[32];
3495 int tt_format_size = 0;
3497 /* Not all functions need anything. */
3498 if (! cfun->uses_eh_lsda)
3501 funcdef_number = (USING_SJLJ_EXCEPTIONS
3502 ? sjlj_funcdef_number
3503 : current_funcdef_number);
3505 #ifdef IA64_UNWIND_INFO
3506 fputs ("\t.personality\t", asm_out_file);
3507 output_addr_const (asm_out_file, eh_personality_libfunc);
3508 fputs ("\n\t.handlerdata\n", asm_out_file);
3509 /* Note that varasm still thinks we're in the function's code section.
3510 The ".endp" directive that will immediately follow will take us back. */
3512 exception_section ();
3515 have_tt_data = (VARRAY_ACTIVE_SIZE (cfun->eh->ttype_data) > 0
3516 || VARRAY_ACTIVE_SIZE (cfun->eh->ehspec_data) > 0);
3518 /* Indicate the format of the @TType entries. */
3520 tt_format = DW_EH_PE_omit;
3523 tt_format = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/0, /*global=*/1);
3524 #ifdef HAVE_AS_LEB128
3525 ASM_GENERATE_INTERNAL_LABEL (ttype_label, "LLSDATT", funcdef_number);
3527 tt_format_size = size_of_encoded_value (tt_format);
3529 assemble_align (tt_format_size * BITS_PER_UNIT);
3532 ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LLSDA", funcdef_number);
3534 /* The LSDA header. */
3536 /* Indicate the format of the landing pad start pointer. An omitted
3537 field implies @LPStart == @Start. */
3538 /* Currently we always put @LPStart == @Start. This field would
3539 be most useful in moving the landing pads completely out of
3540 line to another section, but it could also be used to minimize
3541 the size of uleb128 landing pad offsets. */
3542 lp_format = DW_EH_PE_omit;
3543 dw2_asm_output_data (1, lp_format, "@LPStart format (%s)",
3544 eh_data_format_name (lp_format));
3546 /* @LPStart pointer would go here. */
3548 dw2_asm_output_data (1, tt_format, "@TType format (%s)",
3549 eh_data_format_name (tt_format));
3551 #ifndef HAVE_AS_LEB128
3552 if (USING_SJLJ_EXCEPTIONS)
3553 call_site_len = sjlj_size_of_call_site_table ();
3555 call_site_len = dw2_size_of_call_site_table ();
3558 /* A pc-relative 4-byte displacement to the @TType data. */
3561 #ifdef HAVE_AS_LEB128
3562 char ttype_after_disp_label[32];
3563 ASM_GENERATE_INTERNAL_LABEL (ttype_after_disp_label, "LLSDATTD",
3565 dw2_asm_output_delta_uleb128 (ttype_label, ttype_after_disp_label,
3566 "@TType base offset");
3567 ASM_OUTPUT_LABEL (asm_out_file, ttype_after_disp_label);
3569 /* Ug. Alignment queers things. */
3570 unsigned int before_disp, after_disp, last_disp, disp;
3572 before_disp = 1 + 1;
3573 after_disp = (1 + size_of_uleb128 (call_site_len)
3575 + VARRAY_ACTIVE_SIZE (cfun->eh->action_record_data)
3576 + (VARRAY_ACTIVE_SIZE (cfun->eh->ttype_data)
3582 unsigned int disp_size, pad;
3585 disp_size = size_of_uleb128 (disp);
3586 pad = before_disp + disp_size + after_disp;
3587 if (pad % tt_format_size)
3588 pad = tt_format_size - (pad % tt_format_size);
3591 disp = after_disp + pad;
3593 while (disp != last_disp);
3595 dw2_asm_output_data_uleb128 (disp, "@TType base offset");
3599 /* Indicate the format of the call-site offsets. */
3600 #ifdef HAVE_AS_LEB128
3601 cs_format = DW_EH_PE_uleb128;
3603 cs_format = DW_EH_PE_udata4;
3605 dw2_asm_output_data (1, cs_format, "call-site format (%s)",
3606 eh_data_format_name (cs_format));
3608 #ifdef HAVE_AS_LEB128
3609 ASM_GENERATE_INTERNAL_LABEL (cs_after_size_label, "LLSDACSB",
3611 ASM_GENERATE_INTERNAL_LABEL (cs_end_label, "LLSDACSE",
3613 dw2_asm_output_delta_uleb128 (cs_end_label, cs_after_size_label,
3614 "Call-site table length");
3615 ASM_OUTPUT_LABEL (asm_out_file, cs_after_size_label);
3616 if (USING_SJLJ_EXCEPTIONS)
3617 sjlj_output_call_site_table ();
3619 dw2_output_call_site_table ();
3620 ASM_OUTPUT_LABEL (asm_out_file, cs_end_label);
3622 dw2_asm_output_data_uleb128 (call_site_len,"Call-site table length");
3623 if (USING_SJLJ_EXCEPTIONS)
3624 sjlj_output_call_site_table ();
3626 dw2_output_call_site_table ();
3629 /* ??? Decode and interpret the data for flag_debug_asm. */
3630 n = VARRAY_ACTIVE_SIZE (cfun->eh->action_record_data);
3631 for (i = 0; i < n; ++i)
3632 dw2_asm_output_data (1, VARRAY_UCHAR (cfun->eh->action_record_data, i),
3633 (i ? NULL : "Action record table"));
3636 assemble_align (tt_format_size * BITS_PER_UNIT);
3638 i = VARRAY_ACTIVE_SIZE (cfun->eh->ttype_data);
3641 tree type = VARRAY_TREE (cfun->eh->ttype_data, i);
3643 if (type == NULL_TREE)
3644 type = integer_zero_node;
3646 type = lookup_type_for_runtime (type);
3648 dw2_asm_output_encoded_addr_rtx (tt_format,
3649 expand_expr (type, NULL_RTX, VOIDmode,
3650 EXPAND_INITIALIZER),
3654 #ifdef HAVE_AS_LEB128
3656 ASM_OUTPUT_LABEL (asm_out_file, ttype_label);
3659 /* ??? Decode and interpret the data for flag_debug_asm. */
3660 n = VARRAY_ACTIVE_SIZE (cfun->eh->ehspec_data);
3661 for (i = 0; i < n; ++i)
3662 dw2_asm_output_data (1, VARRAY_UCHAR (cfun->eh->ehspec_data, i),
3663 (i ? NULL : "Exception specification table"));
3665 function_section (current_function_decl);
3667 if (USING_SJLJ_EXCEPTIONS)
3668 sjlj_funcdef_number += 1;