forked from illumos/gcc
/
tree-object-size.c
1281 lines (1093 loc) · 35.1 KB
/
tree-object-size.c
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
/* __builtin_object_size (ptr, object_size_type) computation
Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
Contributed by Jakub Jelinek <jakub@redhat.com>
This file is part of GCC.
GCC 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 3, or (at your option)
any later version.
GCC 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 GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "diagnostic-core.h"
#include "tree-pretty-print.h"
#include "gimple-pretty-print.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "tree-ssa-propagate.h"
struct object_size_info
{
int object_size_type;
bitmap visited, reexamine;
int pass;
bool changed;
unsigned int *depths;
unsigned int *stack, *tos;
};
static unsigned HOST_WIDE_INT unknown[4] = { -1, -1, 0, 0 };
static tree compute_object_offset (const_tree, const_tree);
static unsigned HOST_WIDE_INT addr_object_size (struct object_size_info *,
const_tree, int);
static unsigned HOST_WIDE_INT alloc_object_size (const_gimple, int);
static tree pass_through_call (const_gimple);
static void collect_object_sizes_for (struct object_size_info *, tree);
static void expr_object_size (struct object_size_info *, tree, tree);
static bool merge_object_sizes (struct object_size_info *, tree, tree,
unsigned HOST_WIDE_INT);
static bool plus_stmt_object_size (struct object_size_info *, tree, gimple);
static bool cond_expr_object_size (struct object_size_info *, tree, tree);
static unsigned int compute_object_sizes (void);
static void init_offset_limit (void);
static void check_for_plus_in_loops (struct object_size_info *, tree);
static void check_for_plus_in_loops_1 (struct object_size_info *, tree,
unsigned int);
/* object_sizes[0] is upper bound for number of bytes till the end of
the object.
object_sizes[1] is upper bound for number of bytes till the end of
the subobject (innermost array or field with address taken).
object_sizes[2] is lower bound for number of bytes till the end of
the object and object_sizes[3] lower bound for subobject. */
static unsigned HOST_WIDE_INT *object_sizes[4];
/* Bitmaps what object sizes have been computed already. */
static bitmap computed[4];
/* Maximum value of offset we consider to be addition. */
static unsigned HOST_WIDE_INT offset_limit;
/* Initialize OFFSET_LIMIT variable. */
static void
init_offset_limit (void)
{
if (host_integerp (TYPE_MAX_VALUE (sizetype), 1))
offset_limit = tree_low_cst (TYPE_MAX_VALUE (sizetype), 1);
else
offset_limit = -1;
offset_limit /= 2;
}
/* Compute offset of EXPR within VAR. Return error_mark_node
if unknown. */
static tree
compute_object_offset (const_tree expr, const_tree var)
{
enum tree_code code = PLUS_EXPR;
tree base, off, t;
if (expr == var)
return size_zero_node;
switch (TREE_CODE (expr))
{
case COMPONENT_REF:
base = compute_object_offset (TREE_OPERAND (expr, 0), var);
if (base == error_mark_node)
return base;
t = TREE_OPERAND (expr, 1);
off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
/ BITS_PER_UNIT));
break;
case REALPART_EXPR:
CASE_CONVERT:
case VIEW_CONVERT_EXPR:
case NON_LVALUE_EXPR:
return compute_object_offset (TREE_OPERAND (expr, 0), var);
case IMAGPART_EXPR:
base = compute_object_offset (TREE_OPERAND (expr, 0), var);
if (base == error_mark_node)
return base;
off = TYPE_SIZE_UNIT (TREE_TYPE (expr));
break;
case ARRAY_REF:
base = compute_object_offset (TREE_OPERAND (expr, 0), var);
if (base == error_mark_node)
return base;
t = TREE_OPERAND (expr, 1);
if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
{
code = MINUS_EXPR;
t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t);
}
t = fold_convert (sizetype, t);
off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
break;
case MEM_REF:
gcc_assert (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR);
return double_int_to_tree (sizetype, mem_ref_offset (expr));
default:
return error_mark_node;
}
return size_binop (code, base, off);
}
/* Compute __builtin_object_size for PTR, which is a ADDR_EXPR.
OBJECT_SIZE_TYPE is the second argument from __builtin_object_size.
If unknown, return unknown[object_size_type]. */
static unsigned HOST_WIDE_INT
addr_object_size (struct object_size_info *osi, const_tree ptr,
int object_size_type)
{
tree pt_var, pt_var_size = NULL_TREE, var_size, bytes;
gcc_assert (TREE_CODE (ptr) == ADDR_EXPR);
pt_var = TREE_OPERAND (ptr, 0);
if (REFERENCE_CLASS_P (pt_var))
pt_var = get_base_address (pt_var);
if (pt_var
&& TREE_CODE (pt_var) == MEM_REF
&& TREE_CODE (TREE_OPERAND (pt_var, 0)) == SSA_NAME
&& POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (pt_var, 0))))
{
unsigned HOST_WIDE_INT sz;
if (!osi || (object_size_type & 1) != 0)
{
sz = compute_builtin_object_size (TREE_OPERAND (pt_var, 0),
object_size_type & ~1);
if (host_integerp (TREE_OPERAND (pt_var, 1), 0))
sz -= TREE_INT_CST_LOW (TREE_OPERAND (pt_var, 1));
else
sz = offset_limit;
}
else
{
tree var = TREE_OPERAND (pt_var, 0);
if (osi->pass == 0)
collect_object_sizes_for (osi, var);
if (bitmap_bit_p (computed[object_size_type],
SSA_NAME_VERSION (var)))
sz = object_sizes[object_size_type][SSA_NAME_VERSION (var)];
else
sz = unknown[object_size_type];
if (host_integerp (TREE_OPERAND (pt_var, 1), 0))
sz -= TREE_INT_CST_LOW (TREE_OPERAND (pt_var, 1));
else
sz = offset_limit;
}
if (sz != unknown[object_size_type] && sz < offset_limit)
pt_var_size = size_int (sz);
}
else if (pt_var
&& (SSA_VAR_P (pt_var) || TREE_CODE (pt_var) == STRING_CST)
&& TYPE_SIZE_UNIT (TREE_TYPE (pt_var))
&& host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (pt_var)), 1)
&& (unsigned HOST_WIDE_INT)
tree_low_cst (TYPE_SIZE_UNIT (TREE_TYPE (pt_var)), 1)
< offset_limit)
pt_var_size = TYPE_SIZE_UNIT (TREE_TYPE (pt_var));
else
return unknown[object_size_type];
if (pt_var != TREE_OPERAND (ptr, 0))
{
tree var;
if (object_size_type & 1)
{
var = TREE_OPERAND (ptr, 0);
while (var != pt_var
&& TREE_CODE (var) != BIT_FIELD_REF
&& TREE_CODE (var) != COMPONENT_REF
&& TREE_CODE (var) != ARRAY_REF
&& TREE_CODE (var) != ARRAY_RANGE_REF
&& TREE_CODE (var) != REALPART_EXPR
&& TREE_CODE (var) != IMAGPART_EXPR)
var = TREE_OPERAND (var, 0);
if (var != pt_var && TREE_CODE (var) == ARRAY_REF)
var = TREE_OPERAND (var, 0);
if (! TYPE_SIZE_UNIT (TREE_TYPE (var))
|| ! host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (var)), 1)
|| (pt_var_size
&& tree_int_cst_lt (pt_var_size,
TYPE_SIZE_UNIT (TREE_TYPE (var)))))
var = pt_var;
else if (var != pt_var && TREE_CODE (pt_var) == MEM_REF)
{
tree v = var;
/* For &X->fld, compute object size only if fld isn't the last
field, as struct { int i; char c[1]; } is often used instead
of flexible array member. */
while (v && v != pt_var)
switch (TREE_CODE (v))
{
case ARRAY_REF:
if (TYPE_SIZE_UNIT (TREE_TYPE (TREE_OPERAND (v, 0)))
&& TREE_CODE (TREE_OPERAND (v, 1)) == INTEGER_CST)
{
tree domain
= TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (v, 0)));
if (domain
&& TYPE_MAX_VALUE (domain)
&& TREE_CODE (TYPE_MAX_VALUE (domain))
== INTEGER_CST
&& tree_int_cst_lt (TREE_OPERAND (v, 1),
TYPE_MAX_VALUE (domain)))
{
v = NULL_TREE;
break;
}
}
v = TREE_OPERAND (v, 0);
break;
case REALPART_EXPR:
case IMAGPART_EXPR:
v = NULL_TREE;
break;
case COMPONENT_REF:
if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE)
{
v = NULL_TREE;
break;
}
while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
!= UNION_TYPE
&& TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
!= QUAL_UNION_TYPE)
break;
else
v = TREE_OPERAND (v, 0);
if (TREE_CODE (v) == COMPONENT_REF
&& TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
== RECORD_TYPE)
{
tree fld_chain = DECL_CHAIN (TREE_OPERAND (v, 1));
for (; fld_chain; fld_chain = DECL_CHAIN (fld_chain))
if (TREE_CODE (fld_chain) == FIELD_DECL)
break;
if (fld_chain)
{
v = NULL_TREE;
break;
}
v = TREE_OPERAND (v, 0);
}
while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
!= UNION_TYPE
&& TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
!= QUAL_UNION_TYPE)
break;
else
v = TREE_OPERAND (v, 0);
if (v != pt_var)
v = NULL_TREE;
else
v = pt_var;
break;
default:
v = pt_var;
break;
}
if (v == pt_var)
var = pt_var;
}
}
else
var = pt_var;
if (var != pt_var)
var_size = TYPE_SIZE_UNIT (TREE_TYPE (var));
else if (!pt_var_size)
return unknown[object_size_type];
else
var_size = pt_var_size;
bytes = compute_object_offset (TREE_OPERAND (ptr, 0), var);
if (bytes != error_mark_node)
{
if (TREE_CODE (bytes) == INTEGER_CST
&& tree_int_cst_lt (var_size, bytes))
bytes = size_zero_node;
else
bytes = size_binop (MINUS_EXPR, var_size, bytes);
}
if (var != pt_var
&& pt_var_size
&& TREE_CODE (pt_var) == MEM_REF
&& bytes != error_mark_node)
{
tree bytes2 = compute_object_offset (TREE_OPERAND (ptr, 0), pt_var);
if (bytes2 != error_mark_node)
{
if (TREE_CODE (bytes2) == INTEGER_CST
&& tree_int_cst_lt (pt_var_size, bytes2))
bytes2 = size_zero_node;
else
bytes2 = size_binop (MINUS_EXPR, pt_var_size, bytes2);
bytes = size_binop (MIN_EXPR, bytes, bytes2);
}
}
}
else if (!pt_var_size)
return unknown[object_size_type];
else
bytes = pt_var_size;
if (host_integerp (bytes, 1))
return tree_low_cst (bytes, 1);
return unknown[object_size_type];
}
/* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL.
Handles various allocation calls. OBJECT_SIZE_TYPE is the second
argument from __builtin_object_size. If unknown, return
unknown[object_size_type]. */
static unsigned HOST_WIDE_INT
alloc_object_size (const_gimple call, int object_size_type)
{
tree callee, bytes = NULL_TREE;
tree alloc_size;
int arg1 = -1, arg2 = -1;
gcc_assert (is_gimple_call (call));
callee = gimple_call_fndecl (call);
if (!callee)
return unknown[object_size_type];
alloc_size = lookup_attribute ("alloc_size", TYPE_ATTRIBUTES (TREE_TYPE(callee)));
if (alloc_size && TREE_VALUE (alloc_size))
{
tree p = TREE_VALUE (alloc_size);
arg1 = TREE_INT_CST_LOW (TREE_VALUE (p))-1;
if (TREE_CHAIN (p))
arg2 = TREE_INT_CST_LOW (TREE_VALUE (TREE_CHAIN (p)))-1;
}
if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
switch (DECL_FUNCTION_CODE (callee))
{
case BUILT_IN_CALLOC:
arg2 = 1;
/* fall through */
case BUILT_IN_MALLOC:
case BUILT_IN_ALLOCA:
arg1 = 0;
default:
break;
}
if (arg1 < 0 || arg1 >= (int)gimple_call_num_args (call)
|| TREE_CODE (gimple_call_arg (call, arg1)) != INTEGER_CST
|| (arg2 >= 0
&& (arg2 >= (int)gimple_call_num_args (call)
|| TREE_CODE (gimple_call_arg (call, arg2)) != INTEGER_CST)))
return unknown[object_size_type];
if (arg2 >= 0)
bytes = size_binop (MULT_EXPR,
fold_convert (sizetype, gimple_call_arg (call, arg1)),
fold_convert (sizetype, gimple_call_arg (call, arg2)));
else if (arg1 >= 0)
bytes = fold_convert (sizetype, gimple_call_arg (call, arg1));
if (bytes && host_integerp (bytes, 1))
return tree_low_cst (bytes, 1);
return unknown[object_size_type];
}
/* If object size is propagated from one of function's arguments directly
to its return value, return that argument for GIMPLE_CALL statement CALL.
Otherwise return NULL. */
static tree
pass_through_call (const_gimple call)
{
tree callee = gimple_call_fndecl (call);
if (callee
&& DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
switch (DECL_FUNCTION_CODE (callee))
{
case BUILT_IN_MEMCPY:
case BUILT_IN_MEMMOVE:
case BUILT_IN_MEMSET:
case BUILT_IN_STRCPY:
case BUILT_IN_STRNCPY:
case BUILT_IN_STRCAT:
case BUILT_IN_STRNCAT:
case BUILT_IN_MEMCPY_CHK:
case BUILT_IN_MEMMOVE_CHK:
case BUILT_IN_MEMSET_CHK:
case BUILT_IN_STRCPY_CHK:
case BUILT_IN_STRNCPY_CHK:
case BUILT_IN_STRCAT_CHK:
case BUILT_IN_STRNCAT_CHK:
if (gimple_call_num_args (call) >= 1)
return gimple_call_arg (call, 0);
break;
default:
break;
}
return NULL_TREE;
}
/* Compute __builtin_object_size value for PTR. OBJECT_SIZE_TYPE is the
second argument from __builtin_object_size. */
unsigned HOST_WIDE_INT
compute_builtin_object_size (tree ptr, int object_size_type)
{
gcc_assert (object_size_type >= 0 && object_size_type <= 3);
if (! offset_limit)
init_offset_limit ();
if (TREE_CODE (ptr) == ADDR_EXPR)
return addr_object_size (NULL, ptr, object_size_type);
if (TREE_CODE (ptr) == SSA_NAME
&& POINTER_TYPE_P (TREE_TYPE (ptr))
&& object_sizes[object_size_type] != NULL)
{
if (!bitmap_bit_p (computed[object_size_type], SSA_NAME_VERSION (ptr)))
{
struct object_size_info osi;
bitmap_iterator bi;
unsigned int i;
if (dump_file)
{
fprintf (dump_file, "Computing %s %sobject size for ",
(object_size_type & 2) ? "minimum" : "maximum",
(object_size_type & 1) ? "sub" : "");
print_generic_expr (dump_file, ptr, dump_flags);
fprintf (dump_file, ":\n");
}
osi.visited = BITMAP_ALLOC (NULL);
osi.reexamine = BITMAP_ALLOC (NULL);
osi.object_size_type = object_size_type;
osi.depths = NULL;
osi.stack = NULL;
osi.tos = NULL;
/* First pass: walk UD chains, compute object sizes that
can be computed. osi.reexamine bitmap at the end will
contain what variables were found in dependency cycles
and therefore need to be reexamined. */
osi.pass = 0;
osi.changed = false;
collect_object_sizes_for (&osi, ptr);
/* Second pass: keep recomputing object sizes of variables
that need reexamination, until no object sizes are
increased or all object sizes are computed. */
if (! bitmap_empty_p (osi.reexamine))
{
bitmap reexamine = BITMAP_ALLOC (NULL);
/* If looking for minimum instead of maximum object size,
detect cases where a pointer is increased in a loop.
Although even without this detection pass 2 would eventually
terminate, it could take a long time. If a pointer is
increasing this way, we need to assume 0 object size.
E.g. p = &buf[0]; while (cond) p = p + 4; */
if (object_size_type & 2)
{
osi.depths = XCNEWVEC (unsigned int, num_ssa_names);
osi.stack = XNEWVEC (unsigned int, num_ssa_names);
osi.tos = osi.stack;
osi.pass = 1;
/* collect_object_sizes_for is changing
osi.reexamine bitmap, so iterate over a copy. */
bitmap_copy (reexamine, osi.reexamine);
EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi)
if (bitmap_bit_p (osi.reexamine, i))
check_for_plus_in_loops (&osi, ssa_name (i));
free (osi.depths);
osi.depths = NULL;
free (osi.stack);
osi.stack = NULL;
osi.tos = NULL;
}
do
{
osi.pass = 2;
osi.changed = false;
/* collect_object_sizes_for is changing
osi.reexamine bitmap, so iterate over a copy. */
bitmap_copy (reexamine, osi.reexamine);
EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi)
if (bitmap_bit_p (osi.reexamine, i))
{
collect_object_sizes_for (&osi, ssa_name (i));
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Reexamining ");
print_generic_expr (dump_file, ssa_name (i),
dump_flags);
fprintf (dump_file, "\n");
}
}
}
while (osi.changed);
BITMAP_FREE (reexamine);
}
EXECUTE_IF_SET_IN_BITMAP (osi.reexamine, 0, i, bi)
bitmap_set_bit (computed[object_size_type], i);
/* Debugging dumps. */
if (dump_file)
{
EXECUTE_IF_SET_IN_BITMAP (osi.visited, 0, i, bi)
if (object_sizes[object_size_type][i]
!= unknown[object_size_type])
{
print_generic_expr (dump_file, ssa_name (i),
dump_flags);
fprintf (dump_file,
": %s %sobject size "
HOST_WIDE_INT_PRINT_UNSIGNED "\n",
(object_size_type & 2) ? "minimum" : "maximum",
(object_size_type & 1) ? "sub" : "",
object_sizes[object_size_type][i]);
}
}
BITMAP_FREE (osi.reexamine);
BITMAP_FREE (osi.visited);
}
return object_sizes[object_size_type][SSA_NAME_VERSION (ptr)];
}
return unknown[object_size_type];
}
/* Compute object_sizes for PTR, defined to VALUE, which is not an SSA_NAME. */
static void
expr_object_size (struct object_size_info *osi, tree ptr, tree value)
{
int object_size_type = osi->object_size_type;
unsigned int varno = SSA_NAME_VERSION (ptr);
unsigned HOST_WIDE_INT bytes;
gcc_assert (object_sizes[object_size_type][varno]
!= unknown[object_size_type]);
gcc_assert (osi->pass == 0);
if (TREE_CODE (value) == WITH_SIZE_EXPR)
value = TREE_OPERAND (value, 0);
/* Pointer variables should have been handled by merge_object_sizes. */
gcc_assert (TREE_CODE (value) != SSA_NAME
|| !POINTER_TYPE_P (TREE_TYPE (value)));
if (TREE_CODE (value) == ADDR_EXPR)
bytes = addr_object_size (osi, value, object_size_type);
else
bytes = unknown[object_size_type];
if ((object_size_type & 2) == 0)
{
if (object_sizes[object_size_type][varno] < bytes)
object_sizes[object_size_type][varno] = bytes;
}
else
{
if (object_sizes[object_size_type][varno] > bytes)
object_sizes[object_size_type][varno] = bytes;
}
}
/* Compute object_sizes for PTR, defined to the result of a call. */
static void
call_object_size (struct object_size_info *osi, tree ptr, gimple call)
{
int object_size_type = osi->object_size_type;
unsigned int varno = SSA_NAME_VERSION (ptr);
unsigned HOST_WIDE_INT bytes;
gcc_assert (is_gimple_call (call));
gcc_assert (object_sizes[object_size_type][varno]
!= unknown[object_size_type]);
gcc_assert (osi->pass == 0);
bytes = alloc_object_size (call, object_size_type);
if ((object_size_type & 2) == 0)
{
if (object_sizes[object_size_type][varno] < bytes)
object_sizes[object_size_type][varno] = bytes;
}
else
{
if (object_sizes[object_size_type][varno] > bytes)
object_sizes[object_size_type][varno] = bytes;
}
}
/* Compute object_sizes for PTR, defined to an unknown value. */
static void
unknown_object_size (struct object_size_info *osi, tree ptr)
{
int object_size_type = osi->object_size_type;
unsigned int varno = SSA_NAME_VERSION (ptr);
unsigned HOST_WIDE_INT bytes;
gcc_assert (object_sizes[object_size_type][varno]
!= unknown[object_size_type]);
gcc_assert (osi->pass == 0);
bytes = unknown[object_size_type];
if ((object_size_type & 2) == 0)
{
if (object_sizes[object_size_type][varno] < bytes)
object_sizes[object_size_type][varno] = bytes;
}
else
{
if (object_sizes[object_size_type][varno] > bytes)
object_sizes[object_size_type][varno] = bytes;
}
}
/* Merge object sizes of ORIG + OFFSET into DEST. Return true if
the object size might need reexamination later. */
static bool
merge_object_sizes (struct object_size_info *osi, tree dest, tree orig,
unsigned HOST_WIDE_INT offset)
{
int object_size_type = osi->object_size_type;
unsigned int varno = SSA_NAME_VERSION (dest);
unsigned HOST_WIDE_INT orig_bytes;
if (object_sizes[object_size_type][varno] == unknown[object_size_type])
return false;
if (offset >= offset_limit)
{
object_sizes[object_size_type][varno] = unknown[object_size_type];
return false;
}
if (osi->pass == 0)
collect_object_sizes_for (osi, orig);
orig_bytes = object_sizes[object_size_type][SSA_NAME_VERSION (orig)];
if (orig_bytes != unknown[object_size_type])
orig_bytes = (offset > orig_bytes)
? (unsigned HOST_WIDE_INT) 0 : orig_bytes - offset;
if ((object_size_type & 2) == 0)
{
if (object_sizes[object_size_type][varno] < orig_bytes)
{
object_sizes[object_size_type][varno] = orig_bytes;
osi->changed = true;
}
}
else
{
if (object_sizes[object_size_type][varno] > orig_bytes)
{
object_sizes[object_size_type][varno] = orig_bytes;
osi->changed = true;
}
}
return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig));
}
/* Compute object_sizes for VAR, defined to the result of an assignment
with operator POINTER_PLUS_EXPR. Return true if the object size might
need reexamination later. */
static bool
plus_stmt_object_size (struct object_size_info *osi, tree var, gimple stmt)
{
int object_size_type = osi->object_size_type;
unsigned int varno = SSA_NAME_VERSION (var);
unsigned HOST_WIDE_INT bytes;
tree op0, op1;
if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
{
op0 = gimple_assign_rhs1 (stmt);
op1 = gimple_assign_rhs2 (stmt);
}
else if (gimple_assign_rhs_code (stmt) == ADDR_EXPR)
{
tree rhs = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0);
gcc_assert (TREE_CODE (rhs) == MEM_REF);
op0 = TREE_OPERAND (rhs, 0);
op1 = TREE_OPERAND (rhs, 1);
}
else
gcc_unreachable ();
if (object_sizes[object_size_type][varno] == unknown[object_size_type])
return false;
/* Handle PTR + OFFSET here. */
if (TREE_CODE (op1) == INTEGER_CST
&& (TREE_CODE (op0) == SSA_NAME
|| TREE_CODE (op0) == ADDR_EXPR))
{
if (! host_integerp (op1, 1))
bytes = unknown[object_size_type];
else if (TREE_CODE (op0) == SSA_NAME)
return merge_object_sizes (osi, var, op0, tree_low_cst (op1, 1));
else
{
unsigned HOST_WIDE_INT off = tree_low_cst (op1, 1);
/* op0 will be ADDR_EXPR here. */
bytes = addr_object_size (osi, op0, object_size_type);
if (bytes == unknown[object_size_type])
;
else if (off > offset_limit)
bytes = unknown[object_size_type];
else if (off > bytes)
bytes = 0;
else
bytes -= off;
}
}
else
bytes = unknown[object_size_type];
if ((object_size_type & 2) == 0)
{
if (object_sizes[object_size_type][varno] < bytes)
object_sizes[object_size_type][varno] = bytes;
}
else
{
if (object_sizes[object_size_type][varno] > bytes)
object_sizes[object_size_type][varno] = bytes;
}
return false;
}
/* Compute object_sizes for VAR, defined to VALUE, which is
a COND_EXPR. Return true if the object size might need reexamination
later. */
static bool
cond_expr_object_size (struct object_size_info *osi, tree var, tree value)
{
tree then_, else_;
int object_size_type = osi->object_size_type;
unsigned int varno = SSA_NAME_VERSION (var);
bool reexamine = false;
gcc_assert (TREE_CODE (value) == COND_EXPR);
if (object_sizes[object_size_type][varno] == unknown[object_size_type])
return false;
then_ = COND_EXPR_THEN (value);
else_ = COND_EXPR_ELSE (value);
if (TREE_CODE (then_) == SSA_NAME)
reexamine |= merge_object_sizes (osi, var, then_, 0);
else
expr_object_size (osi, var, then_);
if (TREE_CODE (else_) == SSA_NAME)
reexamine |= merge_object_sizes (osi, var, else_, 0);
else
expr_object_size (osi, var, else_);
return reexamine;
}
/* Compute object sizes for VAR.
For ADDR_EXPR an object size is the number of remaining bytes
to the end of the object (where what is considered an object depends on
OSI->object_size_type).
For allocation GIMPLE_CALL like malloc or calloc object size is the size
of the allocation.
For POINTER_PLUS_EXPR where second operand is a constant integer,
object size is object size of the first operand minus the constant.
If the constant is bigger than the number of remaining bytes until the
end of the object, object size is 0, but if it is instead a pointer
subtraction, object size is unknown[object_size_type].
To differentiate addition from subtraction, ADDR_EXPR returns
unknown[object_size_type] for all objects bigger than half of the address
space, and constants less than half of the address space are considered
addition, while bigger constants subtraction.
For a memcpy like GIMPLE_CALL that always returns one of its arguments, the
object size is object size of that argument.
Otherwise, object size is the maximum of object sizes of variables
that it might be set to. */
static void
collect_object_sizes_for (struct object_size_info *osi, tree var)
{
int object_size_type = osi->object_size_type;
unsigned int varno = SSA_NAME_VERSION (var);
gimple stmt;
bool reexamine;
if (bitmap_bit_p (computed[object_size_type], varno))
return;
if (osi->pass == 0)
{
if (bitmap_set_bit (osi->visited, varno))
{
object_sizes[object_size_type][varno]
= (object_size_type & 2) ? -1 : 0;
}
else
{
/* Found a dependency loop. Mark the variable for later
re-examination. */
bitmap_set_bit (osi->reexamine, varno);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Found a dependency loop at ");
print_generic_expr (dump_file, var, dump_flags);
fprintf (dump_file, "\n");
}
return;
}
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Visiting use-def links for ");
print_generic_expr (dump_file, var, dump_flags);
fprintf (dump_file, "\n");
}
stmt = SSA_NAME_DEF_STMT (var);
reexamine = false;
switch (gimple_code (stmt))
{
case GIMPLE_ASSIGN:
{
tree rhs = gimple_assign_rhs1 (stmt);
if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
|| (gimple_assign_rhs_code (stmt) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == MEM_REF))
reexamine = plus_stmt_object_size (osi, var, stmt);
else if (gimple_assign_single_p (stmt)
|| gimple_assign_unary_nop_p (stmt))
{
if (TREE_CODE (rhs) == SSA_NAME
&& POINTER_TYPE_P (TREE_TYPE (rhs)))
reexamine = merge_object_sizes (osi, var, rhs, 0);
else if (TREE_CODE (rhs) == COND_EXPR)
reexamine = cond_expr_object_size (osi, var, rhs);
else
expr_object_size (osi, var, rhs);
}
else
unknown_object_size (osi, var);
break;
}
case GIMPLE_CALL:
{
tree arg = pass_through_call (stmt);
if (arg)
{
if (TREE_CODE (arg) == SSA_NAME
&& POINTER_TYPE_P (TREE_TYPE (arg)))
reexamine = merge_object_sizes (osi, var, arg, 0);
else if (TREE_CODE (arg) == COND_EXPR)
reexamine = cond_expr_object_size (osi, var, arg);
else
expr_object_size (osi, var, arg);
}
else
call_object_size (osi, var, stmt);
break;
}
case GIMPLE_ASM:
/* Pointers defined by __asm__ statements can point anywhere. */
object_sizes[object_size_type][varno] = unknown[object_size_type];
break;
case GIMPLE_NOP:
{
tree decl = SSA_NAME_VAR (var);
if (TREE_CODE (decl) != PARM_DECL && DECL_INITIAL (decl))
expr_object_size (osi, var, DECL_INITIAL (decl));
else
expr_object_size (osi, var, decl);
}
break;
case GIMPLE_PHI:
{
unsigned i;
for (i = 0; i < gimple_phi_num_args (stmt); i++)
{
tree rhs = gimple_phi_arg (stmt, i)->def;
if (object_sizes[object_size_type][varno]
== unknown[object_size_type])
break;
if (TREE_CODE (rhs) == SSA_NAME)
reexamine |= merge_object_sizes (osi, var, rhs, 0);
else if (osi->pass == 0)
expr_object_size (osi, var, rhs);
}
break;
}
default:
gcc_unreachable ();
}