/
cfg.c
1382 lines (1053 loc) · 33.9 KB
/
cfg.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
/*
* Copyright (C) 2002-2011, Parrot Foundation.
*/
/*
=head1 NAME
compilers/imcc/cfg.c
=head1 DESCRIPTION
A basic block is the longest sequence of instructions that we are sure will be
executed sequentially: no branches, no labels.
The control-flow graph is a directed graph that reflects the flow of execution
between blocks.
=head2 Functions
=over 4
=cut
*/
#include <stdlib.h>
#include <string.h>
#include "imc.h"
#include "optimizer.h"
#include "parrot/oplib/core_ops.h"
/* HEADERIZER HFILE: compilers/imcc/cfg.h */
/* HEADERIZER BEGIN: static */
/* Don't modify between HEADERIZER BEGIN / HEADERIZER END. Your changes will be lost. */
static void bb_add_edge(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit),
ARGIN(Basic_block *from),
ARGMOD(Basic_block *to))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
__attribute__nonnull__(3)
__attribute__nonnull__(4)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit)
FUNC_MODIFIES(*to);
static void bb_check_set_addr(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit),
ARGMOD(Basic_block *bb),
ARGIN(const SymReg *label))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
__attribute__nonnull__(3)
__attribute__nonnull__(4)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit)
FUNC_MODIFIES(*bb);
static void bb_findadd_edge(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit),
ARGIN(Basic_block *from),
ARGIN(const SymReg *label))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
__attribute__nonnull__(3)
__attribute__nonnull__(4)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
static void bb_remove_edge(ARGMOD(IMC_Unit *unit), ARGMOD(Edge *edge))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*unit)
FUNC_MODIFIES(*edge);
PARROT_WARN_UNUSED_RESULT
static int blocks_are_connected(
ARGIN(const Basic_block *from),
ARGIN(const Basic_block *to))
__attribute__nonnull__(1)
__attribute__nonnull__(2);
PARROT_WARN_UNUSED_RESULT
static int check_invoke_type(
ARGMOD(imc_info_t *imcc),
ARGIN(const IMC_Unit *unit),
ARGIN(const Instruction *ins))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
__attribute__nonnull__(3)
FUNC_MODIFIES(*imcc);
static void free_dominance_frontiers(ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
FUNC_MODIFIES(*unit);
static void free_dominators(ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
FUNC_MODIFIES(*unit);
static void free_edge(ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
FUNC_MODIFIES(*unit);
static void free_loops(ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
FUNC_MODIFIES(*unit);
static void init_basic_blocks(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
PARROT_CANNOT_RETURN_NULL
PARROT_WARN_UNUSED_RESULT
static Basic_block* make_basic_block(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit),
ARGMOD(Instruction *ins))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
__attribute__nonnull__(3)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit)
FUNC_MODIFIES(*ins);
static void mark_loop(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit),
ARGIN(const Edge *e))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
__attribute__nonnull__(3)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
static void sort_loops(ARGMOD(imc_info_t *imcc), ARGIN(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc);
#define ASSERT_ARGS_bb_add_edge __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit) \
, PARROT_ASSERT_ARG(from) \
, PARROT_ASSERT_ARG(to))
#define ASSERT_ARGS_bb_check_set_addr __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit) \
, PARROT_ASSERT_ARG(bb) \
, PARROT_ASSERT_ARG(label))
#define ASSERT_ARGS_bb_findadd_edge __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit) \
, PARROT_ASSERT_ARG(from) \
, PARROT_ASSERT_ARG(label))
#define ASSERT_ARGS_bb_remove_edge __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(unit) \
, PARROT_ASSERT_ARG(edge))
#define ASSERT_ARGS_blocks_are_connected __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(from) \
, PARROT_ASSERT_ARG(to))
#define ASSERT_ARGS_check_invoke_type __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit) \
, PARROT_ASSERT_ARG(ins))
#define ASSERT_ARGS_free_dominance_frontiers __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_free_dominators __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_free_edge __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_free_loops __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_init_basic_blocks __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_make_basic_block __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit) \
, PARROT_ASSERT_ARG(ins))
#define ASSERT_ARGS_mark_loop __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit) \
, PARROT_ASSERT_ARG(e))
#define ASSERT_ARGS_sort_loops __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
/* Don't modify between HEADERIZER BEGIN / HEADERIZER END. Your changes will be lost. */
/* HEADERIZER END: static */
/* Code: */
#define INVOKE_SUB_CALL 1
#define INVOKE_SUB_RET 2
#define INVOKE_SUB_LOOP 3
#define INVOKE_SUB_OTHER 4
/*
=item C<static int check_invoke_type(imc_info_t *imcc, const IMC_Unit *unit,
const Instruction *ins)>
Given an invoke-type instruction, returns the type of the invocation.
=cut
*/
PARROT_WARN_UNUSED_RESULT
static int
check_invoke_type(ARGMOD(imc_info_t *imcc), ARGIN(const IMC_Unit *unit),
ARGIN(const Instruction *ins))
{
ASSERT_ARGS(check_invoke_type)
/* 1) pcc sub call or yield */
if (ins->type & (ITPCCSUB | ITPCCYIELD))
return INVOKE_SUB_CALL;
/*
* inside another pcc_sub
* 2) invoke = loop to begin
*/
if (unit->instructions->symregs[0]
&& unit->instructions->symregs[0]->pcc_sub)
return INVOKE_SUB_LOOP;
/* 3) invoke P1 returns */
if (ins->opsize == 2)
return INVOKE_SUB_RET;
/* 4) other usage, too complex to follow */
imcc->dont_optimize = 1;
imcc->optimizer_level &= ~OPT_PASM;
return INVOKE_SUB_OTHER;
}
/*
=item C<void find_basic_blocks(imc_info_t *imcc, IMC_Unit *unit, int first)>
Finds all basic blocks in the given IMC_Unit, expanding PCC calls if first is
true.
=cut
*/
void
find_basic_blocks(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit), int first)
{
ASSERT_ARGS(find_basic_blocks)
Basic_block *bb;
Instruction *ins;
const SymHash * const hsh = &unit->hash;
int nu = 0;
unsigned int i;
IMCC_info(imcc, 2, "find_basic_blocks\n");
init_basic_blocks(imcc, unit);
for (i = 0; i < hsh->size; i++) {
SymReg *r;
for (r = hsh->data[i]; r; r = r->next) {
if (r->type & VTADDRESS)
r->last_ins = NULL;
}
}
ins = unit->instructions;
if (unit->type & IMC_PCCSUB) {
IMCC_debug(imcc, DEBUG_CFG, "pcc_sub %s nparams %d\n",
ins->symregs[0]->name, ins->symregs[0]->pcc_sub->nargs);
expand_pcc_sub(imcc, unit, ins);
}
ins->index = i = 0;
bb = make_basic_block(imcc, unit, ins);
if (ins->type & ITBRANCH) {
SymReg * const addr = get_branch_reg(bb->end);
if (addr)
addr->last_ins = ins;
}
for (ins = ins->next; ins; ins = ins->next) {
bb->end = ins;
ins->index = ++i;
ins->bbindex = unit->n_basic_blocks - 1;
if (!ins->op
&& (ins->type & ITPCCPARAM)
&& first) {
expand_pcc_sub(imcc, unit, ins);
ins->type &= ~ITPCCPARAM;
}
else if (!ins->op
&& (ins->type & ITPCCSUB)
&& first) {
if (ins->type & ITLABEL) {
expand_pcc_sub_ret(imcc, unit, ins);
ins->type &= ~ITLABEL;
}
else {
/* if this is a sub call expand it */
expand_pcc_sub_call(imcc, unit, ins);
}
ins->type &= ~ITPCCSUB;
}
else if (ins->type & ITLABEL) {
/* set the labels address (ins) */
ins->symregs[0]->first_ins = ins;
}
/* a LABEL starts a new basic block, but not, if we already have
* a new one (last was a branch) */
if (nu)
nu = 0;
else if (ins->type & ITLABEL) {
bb->end = ins->prev;
bb = make_basic_block(imcc, unit, ins);
}
/* a branch is the end of a basic block
* so start a new one with the next instruction */
if (ins->type & ITBRANCH) {
SymReg * const addr = get_branch_reg(bb->end);
if (addr)
addr->last_ins = ins;
/* XXX: ignore set_addr - no new basic block.
* No, we need to mark the label. GH #1061 */
#if 0
if (STREQ(ins->opname, "set_addr")) {
continue;
}
#endif
if (ins->next)
bb = make_basic_block(imcc, unit, ins->next);
nu = 1;
}
}
if (imcc->debug & DEBUG_CFG) {
dump_instructions(imcc, unit);
dump_labels(unit);
}
}
/*
=item C<static void bb_check_set_addr(imc_info_t *imcc, IMC_Unit *unit,
Basic_block *bb, const SymReg *label)>
Looks for a C<set_addr> op in the current unit referring to the given label.
=cut
*/
static void
bb_check_set_addr(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
ARGMOD(Basic_block *bb), ARGIN(const SymReg *label))
{
ASSERT_ARGS(bb_check_set_addr)
const Instruction *ins;
op_lib_t *core_ops = PARROT_GET_CORE_OPLIB(imcc->interp);
for (ins = unit->instructions; ins; ins = ins->next) {
if ((ins->op == &core_ops->op_info_table[PARROT_OP_set_addr_p_ic])
&& STREQ(label->name, ins->symregs[1]->name)) {
IMCC_debug(imcc, DEBUG_CFG, "set_addr %s\n",
ins->symregs[1]->name);
/* connect this block with first and last block */
bb_add_edge(imcc, unit, unit->bb_list[0], bb);
bb_add_edge(imcc, unit, unit->bb_list[unit->n_basic_blocks - 1], bb);
break;
}
}
}
/*
=item C<void build_cfg(imc_info_t *imcc, IMC_Unit *unit)>
Once the basic blocks have been computed, build_cfg computes the dependencies
between them.
=cut
*/
void
build_cfg(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(build_cfg)
Basic_block *last = NULL;
unsigned int i;
int changes;
IMCC_info(imcc, 2, "build_cfg\n");
for (i = 0; i < unit->n_basic_blocks; i++) {
Basic_block * const bb = unit->bb_list[i];
SymReg *addr;
/* if the block can fall-through */
if (i > 0 && ! (last->end->type & IF_goto))
bb_add_edge(imcc, unit, last, bb);
/* check first ins, if label try to find a set_addr op */
if (bb->start->type & ITLABEL)
bb_check_set_addr(imcc, unit, bb, bb->start->symregs[0]);
/* look if last instruction is a branch */
addr = get_branch_reg(bb->end);
if (addr)
bb_findadd_edge(imcc, unit, bb, addr);
else if (STREQ(bb->start->opname, "invoke")
|| STREQ(bb->start->opname, "invokecc")) {
if (check_invoke_type(imcc, unit, bb->start) == INVOKE_SUB_LOOP)
bb_add_edge(imcc, unit, bb, unit->bb_list[0]);
}
last = bb;
}
/* Decouple unreachable blocks (not the first block, with no predecessors)
* from the CFG */
do {
unsigned int j;
changes = 0;
for (j = 1; j < unit->n_basic_blocks; j++) {
Basic_block * const bb = unit->bb_list[j];
if (!bb->pred_list) {
/* Remove all successor edges of block bb */
while (bb->succ_list) {
bb_remove_edge(unit, bb->succ_list);
IMCC_debug(imcc, DEBUG_CFG,
"remove edge from bb: %d\n", bb->index);
changes = 1;
}
}
}
} while (changes);
if (imcc->debug & DEBUG_CFG)
dump_cfg(unit);
}
/*
=item C<static void bb_findadd_edge(imc_info_t *imcc, IMC_Unit *unit,
Basic_block *from, const SymReg *label)>
Finds the placement of the given label and links its containing block to the
given basic block.
=cut
*/
static void
bb_findadd_edge(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
ARGIN(Basic_block *from), ARGIN(const SymReg *label))
{
ASSERT_ARGS(bb_findadd_edge)
const SymReg * const r = find_sym(imcc, label->name);
if (r && (r->type & VTADDRESS) && r->first_ins)
bb_add_edge(imcc, unit, from, unit->bb_list[r->first_ins->bbindex]);
else {
const Instruction *ins;
IMCC_debug(imcc, DEBUG_CFG, "register branch %d ", from->end);
for (ins = from->end; ins; ins = ins->prev) {
if ((ins->type & ITBRANCH)
&& STREQ(ins->opname, "set_addr")
&& ins->symregs[1]->first_ins) {
bb_add_edge(imcc, unit, from,
unit-> bb_list[ins->symregs[1]->first_ins->bbindex]);
IMCC_debug(imcc, DEBUG_CFG, "(%s) ", ins->symregs[1]->name);
break;
}
}
IMCC_debug(imcc, DEBUG_CFG, "\n");
}
}
/*
=item C<static int blocks_are_connected(const Basic_block *from, const
Basic_block *to)>
Returns true or false whether the given blocks are linked.
=cut
*/
PARROT_WARN_UNUSED_RESULT
static int
blocks_are_connected(ARGIN(const Basic_block *from), ARGIN(const Basic_block *to))
{
ASSERT_ARGS(blocks_are_connected)
const Edge *pred = to->pred_list;
while (pred) {
/*already linked*/
if (pred->from == from)
return 1;
pred = pred->pred_next;
}
return 0;
}
/*
=item C<static void bb_add_edge(imc_info_t *imcc, IMC_Unit *unit, Basic_block
*from, Basic_block *to)>
Adds an edge between the two given blocks.
=cut
*/
static void
bb_add_edge(ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit),
ARGIN(Basic_block *from),
ARGMOD(Basic_block *to))
{
ASSERT_ARGS(bb_add_edge)
Edge *e;
if (blocks_are_connected(from, to))
return;
/* we assume that the data is correct, and thus if the edge is not
* on the predecessors of 'from', it won't be on the successors of 'to' */
e = mem_gc_allocate_typed(imcc->interp, Edge);
e->succ_next = from->succ_list;
e->from = from;
e->pred_next = to->pred_list;
e->to = to;
to->pred_list = from->succ_list = e;
/* memory housekeeping */
e->next = NULL;
if (unit->edge_list == NULL)
unit->edge_list = e;
else {
e->next = unit->edge_list;
unit->edge_list = e;
}
}
/*
=item C<static void bb_remove_edge(IMC_Unit *unit, Edge *edge)>
Removes the given edge from the graph.
=cut
*/
static void
bb_remove_edge(ARGMOD(IMC_Unit *unit), ARGMOD(Edge *edge))
{
ASSERT_ARGS(bb_remove_edge)
if (edge->from->succ_list == edge) {
edge->from->succ_list = edge->succ_next;
}
else {
Edge *prev;
for (prev = edge->from->succ_list; prev; prev = prev->succ_next) {
if (prev->succ_next == edge)
prev->succ_next = edge->succ_next;
}
}
if (edge->to->pred_list == edge) {
edge->to->pred_list = edge->pred_next;
}
else {
Edge *prev;
for (prev = edge->to->pred_list; prev; prev = prev->pred_next) {
if (prev->pred_next == edge)
prev->pred_next = edge->pred_next;
}
}
if (unit->edge_list == edge) {
unit->edge_list = edge->next;
mem_sys_free(edge);
}
else {
Edge *prev;
for (prev = unit->edge_list; prev; prev = prev->next) {
if (prev->next == edge) {
prev->next = edge->next;
mem_sys_free(edge);
break;
}
}
}
}
/*
=item C<static void free_edge(IMC_Unit *unit)>
Frees the memory of an IMC_Unit's edge list.
=cut
*/
static void
free_edge(ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(free_edge)
Edge *e;
for (e = unit->edge_list; e;) {
Edge * const next = e->next;
mem_sys_free(e);
e = next;
}
unit->edge_list = NULL;
}
/*
=item C<int edge_count(const IMC_Unit *unit)>
Counts and returns the number of edges in the specified IMC_Unit.
=cut
*/
PARROT_WARN_UNUSED_RESULT
PARROT_PURE_FUNCTION
int
edge_count(ARGIN(const IMC_Unit *unit))
{
ASSERT_ARGS(edge_count)
const Edge *e = unit->edge_list;
int i = 0;
while (e) {
i++;
e = e->next;
}
return i;
}
/*
=item C<void compute_dominators(imc_info_t *imcc, IMC_Unit *unit)>
Computes the dominators tree of the CFG. Basic block A dominates B if each
path to B passes through A
See gcc:flow.c compute_dominators
=cut
*/
void
compute_dominators(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(compute_dominators)
#define USE_BFS 0
#if !USE_BFS
int i, change, pred_index;
#else
int i, cur, len, succ_index;
int *q;
Set *visited;
#endif
int b, runner, wrong;
Set **dominators;
const unsigned int n = unit->n_basic_blocks;
IMCC_info(imcc, 2, "compute_dominators\n");
unit->idoms = mem_gc_allocate_n_zeroed_typed(imcc->interp, n, int);
dominators = mem_gc_allocate_n_zeroed_typed(imcc->interp, n, Set *);
unit->dominators = dominators;
dominators[0] = set_make(imcc, n);
set_add(dominators[0], 0);
for (i = n - 1; i; --i) {
if (unit->bb_list[i]->pred_list) {
dominators[i] = set_make_full(imcc, n);
}
else {
dominators[i] = set_make(imcc, n);
set_add(dominators[i], i);
}
}
#if USE_BFS
q = calloc(n, sizeof (int));
visited = set_make(n);
set_add(visited, 0);
len = 1;
cur = 0;
while (cur < len) {
Edge *edge;
for (edge = unit->bb_list[q[cur]]->succ_list;
edge; edge = edge->succ_next) {
succ_index = edge->to->index;
set_intersec_inplace(dominators[succ_index], dominators[q[cur]]);
set_add(dominators[succ_index], succ_index);
if (!set_contains(visited, succ_index)) {
set_add(visited, succ_index);
q[len++] = succ_index;
}
}
cur++;
}
#else
change = 1;
while (change) {
unsigned int i;
change = 0;
/* TODO: This 'for' should be a breadth-first search for speed */
for (i = 1; i < n; i++) {
Set * const s = set_copy(imcc, dominators[i]);
Edge *edge;
for (edge = unit->bb_list[i]->pred_list;
edge;
edge = edge->pred_next) {
pred_index = edge->from->index;
set_intersec_inplace(s, dominators[pred_index]);
}
set_add(s, i);
if (! set_equal(dominators[i], s)) {
change = 1;
set_free(dominators[i]);
dominators[i] = s;
}
else
set_free(s);
}
}
#endif
/* calc idoms */
unit->idoms[0] = unit->bb_list[0]->index;
for (b = n - 1; b; --b) {
unit->idoms[b] = 0;
for (i = n - 1; i > 0; i--) {
if (i != b && set_contains(dominators[b], i)) {
wrong = 0;
for (runner = n - 1; runner >= 0; --runner) {
if (runner != b && runner != i
&& set_contains(dominators[b], runner))
{
if (set_contains(dominators[runner], i)) {
wrong = 1;
break;
}
}
}
if (!wrong) {
unit->idoms[b] = unit->bb_list[i]->index;
break;
}
}
}
}
if (imcc->debug & DEBUG_CFG)
dump_dominators(unit);
#if USE_BFS
mem_sys_free(q);
set_free(visited);
#endif
}
/*
=item C<void compute_dominance_frontiers(imc_info_t *imcc, IMC_Unit *unit)>
Algorithm to find dominance frontiers described in paper "A Simple, Fast
Dominance Algorithm", Cooper et al. (2001)
=cut
*/
void
compute_dominance_frontiers(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(compute_dominance_frontiers)
int i, b;
const int n = unit->n_basic_blocks;
Set ** const dominance_frontiers = unit->dominance_frontiers =
mem_gc_allocate_n_typed(imcc->interp, n, Set *);
IMCC_info(imcc, 2, "compute_dominance_frontiers\n");
for (i = 0; i < n; i++) {
dominance_frontiers[i] = set_make(imcc, n);
}
/* for all nodes, b */
for (b = 1; b < n; b++) {
const Edge *edge = unit->bb_list[b]->pred_list;
/* if the number of predecessors of b >= 2 */
if (edge && edge->pred_next) {
/* for all predecessors, p, of b */
for (; edge; edge = edge->pred_next) {
/* runner = p */
int runner = edge->from->index;
/* while runner != idoms[b] */
while (runner >= 0 && runner != unit->idoms[b]) {
if (set_contains(unit->dominance_frontiers[runner], b))
/* we've already gone down this path once before */
runner = 0;
else
/* add b to runner's dominance frontier set */
set_add(unit->dominance_frontiers[runner], b);
/* runner = idoms[runner] */
if (runner == 0)
runner = -1;
else
runner = unit->idoms[runner];
}
}
}
}
if (imcc->debug & DEBUG_CFG)
dump_dominance_frontiers(unit);
}
/*
=item C<static void free_dominators(IMC_Unit *unit)>
Frees the memory in the given unit related to all dominators.
=cut
*/
static void
free_dominators(ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(free_dominators)
if (unit->dominators) {
unsigned int i;
for (i = 0; i < unit->n_basic_blocks; i++) {
set_free(unit->dominators[i]);
}
mem_sys_free(unit->dominators);
unit->dominators = NULL;
mem_sys_free(unit->idoms);
}
}
/*
=item C<static void free_dominance_frontiers(IMC_Unit *unit)>
Frees the memory in the given unit related to all dominance frontiers.
=cut
*/
static void
free_dominance_frontiers(ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(free_dominance_frontiers)
if (unit->dominance_frontiers) {
unsigned int i;
for (i = 0; i < unit->n_basic_blocks; i++) {
set_free(unit->dominance_frontiers[i]);
}
mem_sys_free(unit->dominance_frontiers);
unit->dominance_frontiers = NULL;
}
}
/*
=item C<static void sort_loops(imc_info_t *imcc, IMC_Unit *unit)>
Sorts the loops found in the CFG of the current unit.
=cut
*/
static void
sort_loops(ARGMOD(imc_info_t *imcc), ARGIN(IMC_Unit *unit))
{
ASSERT_ARGS(sort_loops)
Loop_info *li;
Loop_info **loop_info = unit->loop_info;
int n_loops = (int)unit->n_loops;
int i, k, changed;
unsigned int j;
for (i = 0; i < n_loops; i++) {
loop_info[i]->size = 0;
for (j = 0; j < unit->n_basic_blocks; j++)
if (set_contains(loop_info[i]->loop, j))
loop_info[i]->size++;
}
changed = 1;
while (changed) {
changed = 0;
for (i = 0; n_loops && i < n_loops - 1; i++)
if (loop_info[i]->size < loop_info[i + 1]->size) {
li = loop_info[i];
loop_info[i] = loop_info[i + 1];
loop_info[i+1] = li;
changed = 1;
}