summaryrefslogtreecommitdiff
path: root/gnu/egcs/gcc/cp/except.c
blob: 9e2d6af592aabece0bbd6ed794a9f9df60a77dec (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
/* Handle exceptional things in C++.
   Copyright (C) 1989, 92-97, 1998, 1999 Free Software Foundation, Inc.
   Contributed by Michael Tiemann <tiemann@cygnus.com>
   Rewritten by Mike Stump <mrs@cygnus.com>, based upon an
   initial re-implementation courtesy Tad Hunt.

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


#include "config.h"
#include "system.h"
#include "tree.h"
#include "rtl.h"
#include "cp-tree.h"
#include "flags.h"
#include "obstack.h"
#include "expr.h"
#include "output.h"
#include "except.h"
#include "function.h"
#include "defaults.h"
#include "toplev.h"
#include "eh-common.h"

rtx expand_builtin_return_addr	PROTO((enum built_in_function, int, rtx));

/* Holds the fndecl for __builtin_return_address.  */
tree builtin_return_address_fndecl;

/* A couple of backend routines from m88k.c */

static void push_eh_cleanup PROTO((void));
static tree build_eh_type_type PROTO((tree));
static tree build_eh_type PROTO((tree));
static void expand_end_eh_spec PROTO((tree));
static tree call_eh_info PROTO((void));
static void push_eh_info PROTO((void));
static tree get_eh_info PROTO((void));
static tree get_eh_value PROTO((void));
#if 0
static tree get_eh_type PROTO((void));
static tree get_eh_caught PROTO((void));
static tree get_eh_handlers PROTO((void));
#endif
static tree do_pop_exception PROTO((void));
static void process_start_catch_block PROTO((tree, tree));
static tree build_eh_type_type_ref PROTO((tree));
static tree build_terminate_handler PROTO((void));
static tree alloc_eh_object PROTO((tree));

#if 0
/* This is the startup, and finish stuff per exception table.  */

/* XXX - Tad: exception handling section */
#ifndef EXCEPT_SECTION_ASM_OP
#define EXCEPT_SECTION_ASM_OP	"section\t.gcc_except_table,\"a\",@progbits"
#endif

#ifdef EXCEPT_SECTION_ASM_OP

 /* on machines which support it, the exception table lives in another section,
	but it needs a label so we can reference it...  This sets up that
    label! */
asm (EXCEPT_SECTION_ASM_OP);
exception_table __EXCEPTION_TABLE__[1] = { (void*)0, (void*)0, (void*)0 };
asm (TEXT_SECTION_ASM_OP);

#endif /* EXCEPT_SECTION_ASM_OP */

#ifdef EXCEPT_SECTION_ASM_OP

 /* we need to know where the end of the exception table is... so this
    is how we do it! */

asm (EXCEPT_SECTION_ASM_OP);
exception_table __EXCEPTION_END__[1] = { (void*)-1, (void*)-1, (void*)-1 };
asm (TEXT_SECTION_ASM_OP);

#endif /* EXCEPT_SECTION_ASM_OP */

#endif

#include "decl.h"
#include "insn-flags.h"
#include "obstack.h"

/* ======================================================================
   Briefly the algorithm works like this:

     When a constructor or start of a try block is encountered,
     push_eh_entry (&eh_stack) is called.  Push_eh_entry () creates a
     new entry in the unwind protection stack and returns a label to
     output to start the protection for that block.

     When a destructor or end try block is encountered, pop_eh_entry
     (&eh_stack) is called.  Pop_eh_entry () returns the eh_entry it
     created when push_eh_entry () was called.  The eh_entry structure
     contains three things at this point.  The start protect label,
     the end protect label, and the exception handler label.  The end
     protect label should be output before the call to the destructor
     (if any). If it was a destructor, then its parse tree is stored
     in the finalization variable in the eh_entry structure.  Otherwise
     the finalization variable is set to NULL to reflect the fact that
     it is the end of a try block.  Next, this modified eh_entry node
     is enqueued in the finalizations queue by calling
     enqueue_eh_entry (&queue,entry).

	+---------------------------------------------------------------+
	|XXX: Will need modification to deal with partially		|
	|			constructed arrays of objects		|
	|								|
	|	Basically, this consists of keeping track of how many	|
	|	of the objects have been constructed already (this	|
	|	should be in a register though, so that shouldn't be a	|
	|	problem.						|
	+---------------------------------------------------------------+

     When a catch block is encountered, there is a lot of work to be
     done.

     Since we don't want to generate the catch block inline with the
     regular flow of the function, we need to have some way of doing
     so.  Luckily, we can use sequences to defer the catch sections.
     When the start of a catch block is encountered, we start the
     sequence.  After the catch block is generated, we end the
     sequence.

     Next we must insure that when the catch block is executed, all
     finalizations for the matching try block have been completed.  If
     any of those finalizations throw an exception, we must call
     terminate according to the ARM (section r.15.6.1).  What this
     means is that we need to dequeue and emit finalizations for each
     entry in the eh_queue until we get to an entry with a NULL
     finalization field.  For any of the finalization entries, if it
     is not a call to terminate (), we must protect it by giving it
     another start label, end label, and exception handler label,
     setting its finalization tree to be a call to terminate (), and
     enqueue'ing this new eh_entry to be output at an outer level.
     Finally, after all that is done, we can get around to outputting
     the catch block which basically wraps all the "catch (...) {...}"
     statements in a big if/then/else construct that matches the
     correct block to call.
     
     ===================================================================== */

/* local globals for function calls
   ====================================================================== */

/* Used to cache "terminate" and "__throw_type_match*".  */
static tree Terminate, CatchMatch;

/* Used to cache __find_first_exception_table_match for throw.  */
static tree FirstExceptionMatch;

/* Used to cache a call to __unwind_function.  */
static tree Unwind;

/* ====================================================================== */


/* ========================================================================= */



/* local globals - these local globals are for storing data necessary for
   generating the exception table and code in the correct order.

   ========================================================================= */

extern rtx catch_clauses;
extern tree const_ptr_type_node;

/* ========================================================================= */

/* sets up all the global eh stuff that needs to be initialized at the
   start of compilation.

   This includes:
		- Setting up all the function call trees.  */

void
init_exception_processing ()
{
  /* void vtype () */
  tree vtype = build_function_type (void_type_node, void_list_node);
  
  if (flag_honor_std)
    push_namespace (get_identifier ("std"));
  Terminate = auto_function (get_identifier ("terminate"),
			     vtype, NOT_BUILT_IN);
  TREE_THIS_VOLATILE (Terminate) = 1;
  if (flag_honor_std)
    pop_namespace ();

  push_lang_context (lang_name_c);

  set_exception_lang_code (EH_LANG_C_plus_plus);
  set_exception_version_code (1);

  CatchMatch
    = builtin_function (flag_rtti
			? "__throw_type_match_rtti"
			: "__throw_type_match",
			build_function_type (ptr_type_node,
					     tree_cons (NULL_TREE, const_ptr_type_node,
							tree_cons (NULL_TREE, const_ptr_type_node,
								   tree_cons (NULL_TREE, ptr_type_node,
									      void_list_node)))),
			NOT_BUILT_IN, NULL_PTR);
  FirstExceptionMatch
    = builtin_function ("__find_first_exception_table_match",
			build_function_type (ptr_type_node,
					     tree_cons (NULL_TREE, ptr_type_node,
							void_list_node)),
			NOT_BUILT_IN, NULL_PTR);
  Unwind
    = builtin_function ("__unwind_function",
			build_function_type (void_type_node,
					     tree_cons (NULL_TREE, ptr_type_node,
							void_list_node)),
			NOT_BUILT_IN, NULL_PTR);

  pop_lang_context ();

  /* If we use setjmp/longjmp EH, arrange for all cleanup actions to
     be protected with __terminate.  */
  protect_cleanup_actions_with_terminate = 1;
}

/* Retrieve a pointer to the cp_eh_info node for the current exception.  */

static tree
call_eh_info ()
{
  tree fn;

  fn = get_identifier ("__start_cp_handler");
  if (IDENTIFIER_GLOBAL_VALUE (fn))
    fn = IDENTIFIER_GLOBAL_VALUE (fn);
  else
    {
      tree t1, t, fields[7];

      /* Declare cp_eh_info * __start_cp_handler (void),
	 as defined in exception.cc. */
      push_obstacks_nochange ();
      end_temporary_allocation ();

      /* struct cp_eh_info.  This must match exception.cc.  Note that this
	 type is not pushed anywhere.  */
      t1= make_lang_type (RECORD_TYPE);
      fields[0] = build_lang_field_decl (FIELD_DECL, 
                    get_identifier ("handler_label"), ptr_type_node);
      fields[1] = build_lang_field_decl (FIELD_DECL, 
                    get_identifier ("dynamic_handler_chain"), ptr_type_node);
      fields[2] = build_lang_field_decl (FIELD_DECL, 
                    get_identifier ("info"), ptr_type_node);
      fields[3] = build_lang_field_decl (FIELD_DECL, 
                    get_identifier ("table_index"), ptr_type_node);
      /* N.B.: The fourth field LEN is expected to be
	 the number of fields - 1, not the total number of fields.  */
      finish_builtin_type (t1, "eh_context", fields, 3, ptr_type_node);
      t1 = build_pointer_type (t1);

      t1= make_lang_type (RECORD_TYPE);
      fields[0] = build_lang_field_decl (FIELD_DECL, 
                    get_identifier ("match_function"), ptr_type_node);
      fields[1] = build_lang_field_decl (FIELD_DECL, 
                    get_identifier ("language"), short_integer_type_node);
      fields[2] = build_lang_field_decl (FIELD_DECL, 
                    get_identifier ("version"), short_integer_type_node);
      /* N.B.: The fourth field LEN is expected to be
	 the number of fields - 1, not the total number of fields.  */
      finish_builtin_type (t1, "__eh_info", fields, 2, ptr_type_node);
      t = make_lang_type (RECORD_TYPE);
      fields[0] = build_lang_field_decl (FIELD_DECL, 
                                              get_identifier ("eh_info"), t1);
      fields[1] = build_lang_field_decl (FIELD_DECL, get_identifier ("value"),
					 ptr_type_node);
      fields[2] = build_lang_field_decl (FIELD_DECL, get_identifier ("type"),
					 ptr_type_node);
      fields[3] = build_lang_field_decl
	(FIELD_DECL, get_identifier ("cleanup"),
	 build_pointer_type (build_function_type
			     (ptr_type_node, tree_cons
			      (NULL_TREE, ptr_type_node, void_list_node))));
      fields[4] = build_lang_field_decl (FIELD_DECL, get_identifier ("caught"),
					 boolean_type_node);
      fields[5] = build_lang_field_decl (FIELD_DECL, get_identifier ("next"),
					 build_pointer_type (t));
      fields[6] = build_lang_field_decl
	(FIELD_DECL, get_identifier ("handlers"), long_integer_type_node);
      /* N.B.: The fourth field LEN is expected to be
	 the number of fields - 1, not the total number of fields.  */
      finish_builtin_type (t, "cp_eh_info", fields, 6, ptr_type_node);
      t = build_pointer_type (t);

      /* And now the function.  */
      fn = build_lang_decl (FUNCTION_DECL, fn,
			    build_function_type (t, void_list_node));
      DECL_EXTERNAL (fn) = 1;
      TREE_PUBLIC (fn) = 1;
      DECL_ARTIFICIAL (fn) = 1;
      pushdecl_top_level (fn);
      make_function_rtl (fn);
      pop_obstacks ();
    }
  mark_used (fn);
  return build_function_call (fn, NULL_TREE);
}

/* Retrieve a pointer to the cp_eh_info node for the current exception
   and save it in the current binding level.  */

static void
push_eh_info ()
{
  tree decl, fn = call_eh_info ();

  /* Remember the pointer to the current exception info; it won't change
     during this catch block.  */
  decl = build_decl (VAR_DECL, get_identifier ("__exception_info"),
		     TREE_TYPE (fn));
  DECL_ARTIFICIAL (decl) = 1;
  DECL_INITIAL (decl) = fn;
  decl = pushdecl (decl);
  cp_finish_decl (decl, fn, NULL_TREE, 0, 0);
}

/* Returns a reference to the cp_eh_info node for the current exception.  */

static tree
get_eh_info ()
{
  /* Look for the pointer pushed in push_eh_info.  */
  tree t = lookup_name (get_identifier ("__exception_info"), 0);
  return build_indirect_ref (t, NULL_PTR);
}

/* Returns a reference to the current exception object.  */

static tree
get_eh_value ()
{
  return build_component_ref (get_eh_info (), get_identifier ("value"),
			      NULL_TREE, 0);
}

/* Returns a reference to the current exception type.  */

#if 0
static tree
get_eh_type ()
{
  return build_component_ref (get_eh_info (), get_identifier ("type"),
			      NULL_TREE, 0);
}

/* Returns a reference to whether or not the current exception
   has been caught.  */

static tree
get_eh_caught ()
{
  return build_component_ref (get_eh_info (), get_identifier ("caught"),
			      NULL_TREE, 0);
}

/* Returns a reference to whether or not the current exception
   has been caught.  */

static tree
get_eh_handlers ()
{
  return build_component_ref (get_eh_info (), get_identifier ("handlers"),
			      NULL_TREE, 0);
}
#endif

/* Build a type value for use at runtime for a type that is matched
   against by the exception handling system.  */

static tree
build_eh_type_type (type)
     tree type;
{
  const char *typestring;
  tree exp;

  if (type == error_mark_node)
    return error_mark_node;

  /* peel back references, so they match.  */
  if (TREE_CODE (type) == REFERENCE_TYPE)
    type = TREE_TYPE (type);

  /* Peel off cv qualifiers.  */
  type = TYPE_MAIN_VARIANT (type);

  if (flag_rtti)
    return build1 (ADDR_EXPR, ptr_type_node, get_typeid_1 (type));

  typestring = build_overload_name (type, 1, 1);
  exp = combine_strings (build_string (strlen (typestring)+1, typestring));
  return build1 (ADDR_EXPR, ptr_type_node, exp);
}

/* Build the address of a runtime type for use in the runtime matching
   field of the new exception model */

static tree
build_eh_type_type_ref (type)
     tree type;
{
  const char *typestring;
  tree exp;

  if (type == error_mark_node)
    return error_mark_node;

  /* peel back references, so they match.  */
  if (TREE_CODE (type) == REFERENCE_TYPE)
    type = TREE_TYPE (type);

  /* Peel off cv qualifiers.  */
  type = TYPE_MAIN_VARIANT (type);

  push_obstacks_nochange ();
  end_temporary_allocation ();

  if (flag_rtti)
    {
      exp = get_tinfo_fn (type);
      TREE_USED (exp) = 1;
      mark_inline_for_output (exp);
      exp = build1 (ADDR_EXPR, ptr_type_node, exp);
    }
  else
    {
      typestring = build_overload_name (type, 1, 1);
      exp = combine_strings (build_string (strlen (typestring)+1, typestring));
      exp = build1 (ADDR_EXPR, ptr_type_node, exp);
    }
  pop_obstacks ();
  return (exp);
}


/* Build a type value for use at runtime for a exp that is thrown or
   matched against by the exception handling system.  */

static tree
build_eh_type (exp)
     tree exp;
{
  if (flag_rtti)
    {
      exp = build_typeid (exp);
      return build1 (ADDR_EXPR, ptr_type_node, exp);
    }
  return build_eh_type_type (TREE_TYPE (exp));
}

/* This routine is called to mark all the symbols representing runtime
   type functions in the exception table as haveing been referenced.
   This will make sure code is emitted for them. Called from finish_file. */
void 
mark_all_runtime_matches () 
{
  int x,num;
  void **ptr;
  tree exp;
  
  num = find_all_handler_type_matches (&ptr);
  if (num == 0 || ptr == NULL)
    return;
  
  for (x=0; x <num; x++)
    {
      exp = (tree) ptr[x];
      if (TREE_CODE (exp) == ADDR_EXPR)
        {
          exp = TREE_OPERAND (exp, 0);
          if (TREE_CODE (exp) == FUNCTION_DECL)
            TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (exp)) = 1;
        }
    }
  
  free (ptr);
}

/* Build up a call to __cp_pop_exception, to destroy the exception object
   for the current catch block.  HANDLER is either true or false, telling
   the library whether or not it is being called from an exception handler;
   if it is, it avoids destroying the object on rethrow.  */

static tree
do_pop_exception ()
{
  tree fn, cleanup;
  fn = get_identifier ("__cp_pop_exception");
  if (IDENTIFIER_GLOBAL_VALUE (fn))
    fn = IDENTIFIER_GLOBAL_VALUE (fn);
  else
    {
      /* Declare void __cp_pop_exception (void *),
	 as defined in exception.cc. */
      push_obstacks_nochange ();
      end_temporary_allocation ();
      fn = build_lang_decl
	(FUNCTION_DECL, fn,
	 build_function_type (void_type_node, tree_cons
			      (NULL_TREE, ptr_type_node, void_list_node)));
      DECL_EXTERNAL (fn) = 1;
      TREE_PUBLIC (fn) = 1;
      DECL_ARTIFICIAL (fn) = 1;
      pushdecl_top_level (fn);
      make_function_rtl (fn);
      pop_obstacks ();
    }

  mark_used (fn);
  /* Arrange to do a dynamically scoped cleanup upon exit from this region.  */
  cleanup = lookup_name (get_identifier ("__exception_info"), 0);
  cleanup = build_function_call (fn, expr_tree_cons
				 (NULL_TREE, cleanup, NULL_TREE));
  return cleanup;
}

/* This routine creates the cleanup for the current exception.  */

static void
push_eh_cleanup ()
{
  int yes;

  yes = suspend_momentary ();
  /* All cleanups must last longer than normal.  */
  expand_decl_cleanup (NULL_TREE, do_pop_exception ());
  resume_momentary (yes);
}

/* Build up a call to terminate on the function obstack, for use as an
   exception handler.  */

static tree
build_terminate_handler ()
{
  int yes = suspend_momentary ();
  tree term = build_function_call (Terminate, NULL_TREE);
  resume_momentary (yes);
  return term;
}

/* Call this to start a catch block. Typename is the typename, and identifier
   is the variable to place the object in or NULL if the variable doesn't
   matter.  If typename is NULL, that means its a "catch (...)" or catch
   everything.  In that case we don't need to do any type checking.
   (ie: it ends up as the "else" clause rather than an "else if" clause) */

void
expand_start_catch_block (declspecs, declarator)
     tree declspecs, declarator;
{
  tree decl;

  if (processing_template_decl)
    {
      if (declspecs)
	{
	  decl = grokdeclarator (declarator, declspecs, CATCHPARM,
				 1, NULL_TREE);
	  pushdecl (decl);
	  decl = build_min_nt (DECL_STMT, copy_to_permanent (declarator),
			       copy_to_permanent (declspecs),
			       NULL_TREE);
	  add_tree (decl);
	}
      return;
    }

  if (! doing_eh (1))
    return;

  process_start_catch_block (declspecs, declarator);
}


/* This function performs the expand_start_catch_block functionality for 
   exceptions implemented in the new style. __throw determines whether
   a handler needs to be called or not, so the handler itself has to do
   nothing additional. */

static void 
process_start_catch_block (declspecs, declarator)
     tree declspecs, declarator;
{
  tree decl = NULL_TREE;
  tree init;

  /* Create a binding level for the eh_info and the exception object
     cleanup.  */
  pushlevel (0);
  expand_start_bindings (0);


  if (declspecs)
    {
      decl = grokdeclarator (declarator, declspecs, CATCHPARM, 1, NULL_TREE);

      if (decl == NULL_TREE)
	error ("invalid catch parameter");
    }

  if (decl)
    start_catch_handler (build_eh_type_type_ref (TREE_TYPE (decl)));
  else
    start_catch_handler (CATCH_ALL_TYPE);

  emit_line_note (input_filename, lineno);

  push_eh_info ();

  if (decl)
    {
      tree exp;
      tree init_type;

      /* Make sure we mark the catch param as used, otherwise we'll get
	 a warning about an unused ((anonymous)).  */
      TREE_USED (decl) = 1;

      /* Figure out the type that the initializer is.  */
      init_type = TREE_TYPE (decl);
      if (TREE_CODE (init_type) != REFERENCE_TYPE
	  && TREE_CODE (init_type) != POINTER_TYPE)
	init_type = build_reference_type (init_type);

      exp = get_eh_value ();

      /* Since pointers are passed by value, initialize a reference to
	 pointer catch parm with the address of the value slot.  */
      if (TREE_CODE (init_type) == REFERENCE_TYPE
	  && TREE_CODE (TREE_TYPE (init_type)) == POINTER_TYPE)
	exp = build_unary_op (ADDR_EXPR, exp, 1);

      exp = ocp_convert (init_type , exp, CONV_IMPLICIT|CONV_FORCE_TEMP, 0);

      push_eh_cleanup ();

      /* Create a binding level for the parm.  */
      pushlevel (0);
      expand_start_bindings (0);

      init = convert_from_reference (exp);

      /* If the constructor for the catch parm exits via an exception, we
         must call terminate.  See eh23.C.  */
      if (TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl)))
	{
	  /* Generate the copy constructor call directly so we can wrap it.
	     See also expand_default_init.  */
	  init = ocp_convert (TREE_TYPE (decl), init,
			      CONV_IMPLICIT|CONV_FORCE_TEMP, 0);
	  init = build (TRY_CATCH_EXPR, TREE_TYPE (init), init,
			build_terminate_handler ());
	}

      /* Let `cp_finish_decl' know that this initializer is ok.  */
      DECL_INITIAL (decl) = init;
      decl = pushdecl (decl);

      start_decl_1 (decl);
      cp_finish_decl (decl, init, NULL_TREE, 0,
		      LOOKUP_ONLYCONVERTING|DIRECT_BIND);
    }
  else
    {
      push_eh_cleanup ();

      /* Create a binding level for the parm.  */
      pushlevel (0);
      expand_start_bindings (0);

      /* Fall into the catch all section.  */
    }

  emit_line_note (input_filename, lineno);
}


/* Call this to end a catch block.  Its responsible for emitting the
   code to handle jumping back to the correct place, and for emitting
   the label to jump to if this catch block didn't match.  */

void
expand_end_catch_block ()
{
  if (! doing_eh (1))
    return;

  /* Cleanup the EH parameter.  */
  expand_end_bindings (getdecls (), kept_level_p (), 0);
  poplevel (kept_level_p (), 1, 0);
      
  /* Cleanup the EH object.  */
  expand_end_bindings (getdecls (), kept_level_p (), 0);
  poplevel (kept_level_p (), 1, 0);

  /* Fall to outside the try statement when done executing handler and
     we fall off end of handler.  This is jump Lresume in the
     documentation.  */
  expand_goto (top_label_entry (&caught_return_label_stack));

  end_catch_handler ();
}

/* An exception spec is implemented more or less like:

   try {
     function body;
   } catch (...) {
     void *p[] = { typeid(raises) };
     __check_eh_spec (p, count);
   }

   __check_eh_spec in exception.cc handles all the details.  */

void
expand_start_eh_spec ()
{
  expand_start_try_stmts ();
}

static void
expand_end_eh_spec (raises)
     tree raises;
{
  tree tmp, fn, decl, types = NULL_TREE;
  int count = 0;

  expand_start_all_catch ();
  expand_start_catch_block (NULL_TREE, NULL_TREE);

  /* Build up an array of type_infos.  */
  for (; raises && TREE_VALUE (raises); raises = TREE_CHAIN (raises))
    {
      types = expr_tree_cons
	(NULL_TREE, build_eh_type_type (TREE_VALUE (raises)), types);
      ++count;
    }

  types = build_nt (CONSTRUCTOR, NULL_TREE, types);
  TREE_HAS_CONSTRUCTOR (types) = 1;

  /* We can't pass the CONSTRUCTOR directly, so stick it in a variable.  */
  tmp = build_cplus_array_type (const_ptr_type_node, NULL_TREE);
  decl = build_decl (VAR_DECL, NULL_TREE, tmp);
  DECL_ARTIFICIAL (decl) = 1;
  DECL_INITIAL (decl) = types;
  cp_finish_decl (decl, types, NULL_TREE, 0, 0);

  decl = decay_conversion (decl);

  fn = get_identifier ("__check_eh_spec");
  if (IDENTIFIER_GLOBAL_VALUE (fn))
    fn = IDENTIFIER_GLOBAL_VALUE (fn);
  else
    {
      push_obstacks_nochange ();
      end_temporary_allocation ();

      tmp = tree_cons
	(NULL_TREE, integer_type_node, tree_cons
	 (NULL_TREE, TREE_TYPE (decl), void_list_node));
      tmp = build_function_type	(void_type_node, tmp);
  
      fn = build_lang_decl (FUNCTION_DECL, fn, tmp);
      DECL_EXTERNAL (fn) = 1;
      TREE_PUBLIC (fn) = 1;
      DECL_ARTIFICIAL (fn) = 1;
      TREE_THIS_VOLATILE (fn) = 1;
      pushdecl_top_level (fn);
      make_function_rtl (fn);
      pop_obstacks ();
    }

  mark_used (fn);
  tmp = expr_tree_cons (NULL_TREE, build_int_2 (count, 0), expr_tree_cons
			(NULL_TREE, decl, NULL_TREE));
  tmp = build_call (fn, TREE_TYPE (TREE_TYPE (fn)), tmp);
  expand_expr (tmp, const0_rtx, VOIDmode, EXPAND_NORMAL);

  expand_end_catch_block ();
  expand_end_all_catch ();
}

/* This is called to expand all the toplevel exception handling
   finalization for a function.  It should only be called once per
   function.  */

void
expand_exception_blocks ()
{
  do_pending_stack_adjust ();
  push_to_sequence (catch_clauses);
  expand_leftover_cleanups ();
  do_pending_stack_adjust ();
  catch_clauses = get_insns ();
  end_sequence ();

  /* Do this after we expand leftover cleanups, so that the
     expand_eh_region_end that expand_end_eh_spec does will match the
     right expand_eh_region_start, and make sure it comes out before
     the terminate protected region.  */
  if (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (current_function_decl)))
    {
     expand_end_eh_spec (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (current_function_decl)));
     do_pending_stack_adjust ();
     push_to_sequence (catch_clauses);
     expand_leftover_cleanups ();
     do_pending_stack_adjust ();
     catch_clauses = get_insns ();
     end_sequence ();
    }

  if (catch_clauses)
    {
      rtx funcend = gen_label_rtx ();
      emit_jump (funcend);

      /* We cannot protect n regions this way if we must flow into the
	 EH region through the top of the region, as we have to with
	 the setjmp/longjmp approach.  */
      if (exceptions_via_longjmp == 0)
	expand_eh_region_start ();

      emit_insns (catch_clauses);
      catch_clauses = NULL_RTX;

      if (exceptions_via_longjmp == 0)
	expand_eh_region_end (build_terminate_handler ());

      expand_leftover_cleanups ();

      emit_label (funcend);
    }
}

tree
start_anon_func ()
{
  static int counter = 0;
  int old_interface_unknown = interface_unknown;
  char name[32];
  tree params;
  tree t;

  push_cp_function_context (NULL_TREE);
  push_to_top_level ();

  /* No need to mangle this.  */
  push_lang_context (lang_name_c);

  interface_unknown = 1;

  params = void_list_node;
  /* tcf stands for throw clean function.  */
  sprintf (name, "__tcf_%d", counter++);
  t = make_call_declarator (get_identifier (name), params, NULL_TREE,
			    NULL_TREE);
  start_function (decl_tree_cons (NULL_TREE, get_identifier ("static"),
				  void_list_node),
		  t, NULL_TREE, 0);
  store_parm_decls ();
  pushlevel (0);
  clear_last_expr ();
  push_momentary ();
  expand_start_bindings (0);
  emit_line_note (input_filename, lineno);

  interface_unknown = old_interface_unknown;

  pop_lang_context ();

  return current_function_decl;
}

void
end_anon_func ()
{
  expand_end_bindings (getdecls (), 1, 0);
  poplevel (1, 0, 0);
  pop_momentary ();

  finish_function (lineno, 0, 0);

  pop_from_top_level ();
  pop_cp_function_context (NULL_TREE);
}

/* Return a pointer to a buffer for an exception object of type TYPE.  */

static tree
alloc_eh_object (type)
     tree type;
{
  tree fn, exp;

  fn = get_identifier ("__eh_alloc");
  if (IDENTIFIER_GLOBAL_VALUE (fn))
    fn = IDENTIFIER_GLOBAL_VALUE (fn);
  else
    {
      /* Declare __eh_alloc (size_t), as defined in exception.cc.  */
      tree tmp;
      push_obstacks_nochange ();
      end_temporary_allocation ();
      tmp = tree_cons (NULL_TREE, sizetype, void_list_node);
      fn = build_lang_decl (FUNCTION_DECL, fn,
			    build_function_type (ptr_type_node, tmp));
      DECL_EXTERNAL (fn) = 1;
      TREE_PUBLIC (fn) = 1;
      DECL_ARTIFICIAL (fn) = 1;
      pushdecl_top_level (fn);
      make_function_rtl (fn);
      pop_obstacks ();
    }

  mark_used (fn);
  exp = build_function_call (fn, expr_tree_cons
			     (NULL_TREE, size_in_bytes (type), NULL_TREE));
  exp = build1 (NOP_EXPR, build_pointer_type (type), exp);
  return exp;
}

/* Expand a throw statement.  This follows the following
   algorithm:

	1. Allocate space to save the current PC onto the stack.
	2. Generate and emit a label and save its address into the
		newly allocated stack space since we can't save the pc directly.
	3. If this is the first call to throw in this function:
		generate a label for the throw block
	4. jump to the throw block label.  */

void
expand_throw (exp)
     tree exp;
{
  tree fn;
  static tree cleanup_type;

  if (! doing_eh (1))
    return;

  if (exp)
    {
      tree throw_type;
      tree cleanup = NULL_TREE, e;

      /* throw expression */
      /* First, decay it.  */
      exp = decay_conversion (exp);

      /* cleanup_type is void (*)(void *, int),
	 the internal type of a destructor. */
      if (cleanup_type == NULL_TREE)
	{
	  push_obstacks_nochange ();
	  end_temporary_allocation ();
	  cleanup_type = build_pointer_type
	    (build_function_type
	     (void_type_node, tree_cons
	      (NULL_TREE, ptr_type_node, tree_cons
	       (NULL_TREE, integer_type_node, void_list_node))));
	  pop_obstacks ();
	}

      if (TYPE_PTR_P (TREE_TYPE (exp)))
	throw_type = build_eh_type (exp);
      else
	{
	  tree object, ptr;

	  /* OK, this is kind of wacky.  The WP says that we call
	     terminate

	     when the exception handling mechanism, after completing
	     evaluation of the expression to be thrown but before the
	     exception is caught (_except.throw_), calls a user function
	     that exits via an uncaught exception.

	     So we have to protect the actual initialization of the
	     exception object with terminate(), but evaluate the expression
	     first.  We also expand the call to __eh_alloc
	     first.  Since there could be temps in the expression, we need
	     to handle that, too.  */

	  expand_start_target_temps ();

#if 0
	  /* Unfortunately, this doesn't work.  */
	  preexpand_calls (exp);
#else
	  /* Store the throw expression into a temp.  This can be less
	     efficient than storing it into the allocated space directly, but
	     oh well.  To do this efficiently we would need to insinuate
	     ourselves into expand_call.  */
	  if (TREE_SIDE_EFFECTS (exp))
	    {
	      tree temp = build_decl (VAR_DECL, NULL_TREE, TREE_TYPE (exp));
	      DECL_ARTIFICIAL (temp) = 1;
	      DECL_RTL (temp) = assign_temp (TREE_TYPE (exp), 2, 0, 1);
	      DECL_INITIAL (temp) = exp;
	      cp_finish_decl (temp, exp, NULL_TREE, 0, LOOKUP_ONLYCONVERTING);
	      exp = temp;
	    }
#endif

	  /* Allocate the space for the exception.  */
	  ptr = save_expr (alloc_eh_object (TREE_TYPE (exp)));
	  expand_expr (ptr, const0_rtx, VOIDmode, 0);

	  expand_eh_region_start ();

	  object = build_indirect_ref (ptr, NULL_PTR);
	  exp = build_modify_expr (object, INIT_EXPR, exp);

	  if (exp == error_mark_node)
	    error ("  in thrown expression");

	  expand_expr (exp, const0_rtx, VOIDmode, 0);
	  expand_eh_region_end (build_terminate_handler ());
	  expand_end_target_temps ();

	  throw_type = build_eh_type (object);

	  if (TYPE_HAS_DESTRUCTOR (TREE_TYPE (object)))
	    {
	      cleanup = lookup_fnfields (TYPE_BINFO (TREE_TYPE (object)),
					 dtor_identifier, 0);
	      cleanup = TREE_VALUE (cleanup);
	      mark_used (cleanup);
	      mark_addressable (cleanup);
	      /* Pretend it's a normal function.  */
	      cleanup = build1 (ADDR_EXPR, cleanup_type, cleanup);
	    }

	  exp = ptr;
	}

      /* Cast EXP to `void *' so that it will match the prototype for
	 __cp_push_exception.  */
      exp = convert (ptr_type_node, exp);

      if (cleanup == NULL_TREE)
	{
	  cleanup = build_int_2 (0, 0);
	  TREE_TYPE (cleanup) = cleanup_type;
	}

      fn = get_identifier ("__cp_push_exception");
      if (IDENTIFIER_GLOBAL_VALUE (fn))
	fn = IDENTIFIER_GLOBAL_VALUE (fn);
      else
	{
	  /* Declare __cp_push_exception (void*, void*, void (*)(void*, int)),
	     as defined in exception.cc.  */
	  tree tmp;
	  push_obstacks_nochange ();
	  end_temporary_allocation ();
	  tmp = tree_cons
	    (NULL_TREE, ptr_type_node, tree_cons
	     (NULL_TREE, ptr_type_node, tree_cons
	      (NULL_TREE, cleanup_type, void_list_node)));
	  fn = build_lang_decl (FUNCTION_DECL, fn,
				build_function_type (void_type_node, tmp));
	  DECL_EXTERNAL (fn) = 1;
	  TREE_PUBLIC (fn) = 1;
	  DECL_ARTIFICIAL (fn) = 1;
	  pushdecl_top_level (fn);
	  make_function_rtl (fn);
	  pop_obstacks ();
	}

      mark_used (fn);
      e = expr_tree_cons (NULL_TREE, exp, expr_tree_cons
			  (NULL_TREE, throw_type, expr_tree_cons
			   (NULL_TREE, cleanup, NULL_TREE)));
      e = build_function_call (fn, e);
      expand_expr (e, const0_rtx, VOIDmode, 0);
    }
  else
    {
      /* rethrow current exception; note that it's no longer caught.  */

      tree fn = get_identifier ("__uncatch_exception");
      if (IDENTIFIER_GLOBAL_VALUE (fn))
	fn = IDENTIFIER_GLOBAL_VALUE (fn);
      else
	{
	  /* Declare void __uncatch_exception (void)
	     as defined in exception.cc. */
	  push_obstacks_nochange ();
	  end_temporary_allocation ();
	  fn = build_lang_decl (FUNCTION_DECL, fn,
				build_function_type (void_type_node,
						     void_list_node));
	  DECL_EXTERNAL (fn) = 1;
	  TREE_PUBLIC (fn) = 1;
	  DECL_ARTIFICIAL (fn) = 1;
	  pushdecl_top_level (fn);
	  make_function_rtl (fn);
	  pop_obstacks ();
	}

      mark_used (fn);
      exp = build_function_call (fn, NULL_TREE);
      expand_expr (exp, const0_rtx, VOIDmode, EXPAND_NORMAL);
    }

  expand_internal_throw ();
}

/* Build a throw expression.  */

tree
build_throw (e)
     tree e;
{
  if (e == error_mark_node)
    return e;

  if (processing_template_decl)
    return build_min (THROW_EXPR, void_type_node, e);

  if (e == null_node)
    cp_warning ("throwing NULL, which has integral, not pointer type");

  e = build1 (THROW_EXPR, void_type_node, e);
  TREE_SIDE_EFFECTS (e) = 1;
  TREE_USED (e) = 1;

  return e;
}