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
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
|
/* Interprocedural constant propagation
Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
Free Software Foundation, Inc.
Contributed by Razya Ladelsky <RAZYA@il.ibm.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/>. */
/* Interprocedural constant propagation. The aim of interprocedural constant
propagation (IPCP) is to find which function's argument has the same
constant value in each invocation throughout the whole program. For example,
consider the following program:
int g (int y)
{
printf ("value is %d",y);
}
int f (int x)
{
g (x);
}
int h (int y)
{
g (y);
}
void main (void)
{
f (3);
h (3);
}
The IPCP algorithm will find that g's formal argument y is always called
with the value 3.
The algorithm used is based on "Interprocedural Constant Propagation", by
David Callahan, Keith D Cooper, Ken Kennedy, Linda Torczon, Comp86, pg
152-161
The optimization is divided into three stages:
First stage - intraprocedural analysis
=======================================
This phase computes jump_function and modification flags.
A jump function for a callsite represents the values passed as an actual
arguments of a given callsite. There are three types of values:
Pass through - the caller's formal parameter is passed as an actual argument.
Constant - a constant is passed as an actual argument.
Unknown - neither of the above.
The jump function info, ipa_jump_func, is stored in ipa_edge_args
structure (defined in ipa_prop.h and pointed to by cgraph_node->aux)
modified_flags are defined in ipa_node_params structure
(defined in ipa_prop.h and pointed to by cgraph_edge->aux).
-ipcp_generate_summary() is the first stage driver.
Second stage - interprocedural analysis
========================================
This phase does the interprocedural constant propagation.
It computes lattices for all formal parameters in the program
and their value that may be:
TOP - unknown.
BOTTOM - non constant.
CONSTANT - constant value.
Lattice describing a formal parameter p will have a constant value if all
callsites invoking this function have the same constant value passed to p.
The lattices are stored in ipcp_lattice which is itself in ipa_node_params
structure (defined in ipa_prop.h and pointed to by cgraph_edge->aux).
-ipcp_iterate_stage() is the second stage driver.
Third phase - transformation of function code
============================================
Propagates the constant-valued formals into the function.
For each function whose parameters are constants, we create its clone.
Then we process the clone in two ways:
1. We insert an assignment statement 'parameter = const' at the beginning
of the cloned function.
2. For read-only parameters that do not live in memory, we replace all their
uses with the constant.
We also need to modify some callsites to call the cloned functions instead
of the original ones. For a callsite passing an argument found to be a
constant by IPCP, there are two different cases to handle:
1. A constant is passed as an argument. In this case the callsite in the
should be redirected to call the cloned callee.
2. A parameter (of the caller) passed as an argument (pass through
argument). In such cases both the caller and the callee have clones and
only the callsite in the cloned caller is redirected to call to the
cloned callee.
This update is done in two steps: First all cloned functions are created
during a traversal of the call graph, during which all callsites are
redirected to call the cloned function. Then the callsites are traversed
and many calls redirected back to fit the description above.
-ipcp_insert_stage() is the third phase driver.
This pass also performs devirtualization - turns virtual calls into direct
ones if it can prove that all invocations of the function call the same
callee. This is achieved by building a list of all base types (actually,
their BINFOs) that individual parameters can have in an iterative matter
just like propagating scalar constants and then examining whether virtual
calls which take a parameter as their object fold to the same target for all
these types. If we cannot enumerate all types or there is a type which does
not have any BINFO associated with it, cannot_devirtualize of the associated
parameter descriptor is set which is an equivalent of BOTTOM lattice value
in standard IPA constant propagation.
*/
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
#include "target.h"
#include "gimple.h"
#include "cgraph.h"
#include "ipa-prop.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "flags.h"
#include "timevar.h"
#include "diagnostic.h"
#include "tree-pretty-print.h"
#include "tree-dump.h"
#include "tree-inline.h"
#include "fibheap.h"
#include "params.h"
#include "ipa-inline.h"
/* Number of functions identified as candidates for cloning. When not cloning
we can simplify iterate stage not forcing it to go through the decision
on what is profitable and what not. */
static int n_cloning_candidates;
/* Maximal count found in program. */
static gcov_type max_count;
/* Cgraph nodes that has been completely replaced by cloning during iterate
* stage and will be removed after ipcp is finished. */
static bitmap dead_nodes;
static void ipcp_print_profile_data (FILE *);
static void ipcp_function_scale_print (FILE *);
/* Get the original node field of ipa_node_params associated with node NODE. */
static inline struct cgraph_node *
ipcp_get_orig_node (struct cgraph_node *node)
{
return IPA_NODE_REF (node)->ipcp_orig_node;
}
/* Return true if NODE describes a cloned/versioned function. */
static inline bool
ipcp_node_is_clone (struct cgraph_node *node)
{
return (ipcp_get_orig_node (node) != NULL);
}
/* Create ipa_node_params and its data structures for NEW_NODE. Set ORIG_NODE
as the ipcp_orig_node field in ipa_node_params. */
static void
ipcp_init_cloned_node (struct cgraph_node *orig_node,
struct cgraph_node *new_node)
{
gcc_checking_assert (ipa_node_params_vector
&& (VEC_length (ipa_node_params_t,
ipa_node_params_vector)
> (unsigned) cgraph_max_uid));
gcc_checking_assert (IPA_NODE_REF (new_node)->params);
IPA_NODE_REF (new_node)->ipcp_orig_node = orig_node;
}
/* Return scale for NODE. */
static inline gcov_type
ipcp_get_node_scale (struct cgraph_node *node)
{
return IPA_NODE_REF (node)->count_scale;
}
/* Set COUNT as scale for NODE. */
static inline void
ipcp_set_node_scale (struct cgraph_node *node, gcov_type count)
{
IPA_NODE_REF (node)->count_scale = count;
}
/* Return whether LAT is a constant lattice. */
static inline bool
ipcp_lat_is_const (struct ipcp_lattice *lat)
{
if (lat->type == IPA_CONST_VALUE)
return true;
else
return false;
}
/* Return whether LAT is a constant lattice that ipa-cp can actually insert
into the code (i.e. constants excluding member pointers and pointers). */
static inline bool
ipcp_lat_is_insertable (struct ipcp_lattice *lat)
{
return lat->type == IPA_CONST_VALUE;
}
/* Return true if LAT1 and LAT2 are equal. */
static inline bool
ipcp_lats_are_equal (struct ipcp_lattice *lat1, struct ipcp_lattice *lat2)
{
gcc_assert (ipcp_lat_is_const (lat1) && ipcp_lat_is_const (lat2));
if (lat1->type != lat2->type)
return false;
if (TREE_CODE (lat1->constant) == ADDR_EXPR
&& TREE_CODE (lat2->constant) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (lat1->constant, 0)) == CONST_DECL
&& TREE_CODE (TREE_OPERAND (lat2->constant, 0)) == CONST_DECL)
return operand_equal_p (DECL_INITIAL (TREE_OPERAND (lat1->constant, 0)),
DECL_INITIAL (TREE_OPERAND (lat2->constant, 0)), 0);
else
return operand_equal_p (lat1->constant, lat2->constant, 0);
}
/* Compute Meet arithmetics:
Meet (IPA_BOTTOM, x) = IPA_BOTTOM
Meet (IPA_TOP,x) = x
Meet (const_a,const_b) = IPA_BOTTOM, if const_a != const_b.
MEET (const_a,const_b) = const_a, if const_a == const_b.*/
static void
ipa_lattice_meet (struct ipcp_lattice *res, struct ipcp_lattice *lat1,
struct ipcp_lattice *lat2)
{
if (lat1->type == IPA_BOTTOM || lat2->type == IPA_BOTTOM)
{
res->type = IPA_BOTTOM;
return;
}
if (lat1->type == IPA_TOP)
{
res->type = lat2->type;
res->constant = lat2->constant;
return;
}
if (lat2->type == IPA_TOP)
{
res->type = lat1->type;
res->constant = lat1->constant;
return;
}
if (!ipcp_lats_are_equal (lat1, lat2))
{
res->type = IPA_BOTTOM;
return;
}
res->type = lat1->type;
res->constant = lat1->constant;
}
/* Return the lattice corresponding to the Ith formal parameter of the function
described by INFO. */
static inline struct ipcp_lattice *
ipcp_get_lattice (struct ipa_node_params *info, int i)
{
return &(info->params[i].ipcp_lattice);
}
/* Given the jump function JFUNC, compute the lattice LAT that describes the
value coming down the callsite. INFO describes the caller node so that
pass-through jump functions can be evaluated. */
static void
ipcp_lattice_from_jfunc (struct ipa_node_params *info, struct ipcp_lattice *lat,
struct ipa_jump_func *jfunc)
{
if (jfunc->type == IPA_JF_CONST)
{
lat->type = IPA_CONST_VALUE;
lat->constant = jfunc->value.constant;
}
else if (jfunc->type == IPA_JF_PASS_THROUGH)
{
struct ipcp_lattice *caller_lat;
tree cst;
caller_lat = ipcp_get_lattice (info, jfunc->value.pass_through.formal_id);
lat->type = caller_lat->type;
if (caller_lat->type != IPA_CONST_VALUE)
return;
cst = caller_lat->constant;
if (jfunc->value.pass_through.operation != NOP_EXPR)
{
tree restype;
if (TREE_CODE_CLASS (jfunc->value.pass_through.operation)
== tcc_comparison)
restype = boolean_type_node;
else
restype = TREE_TYPE (cst);
cst = fold_binary (jfunc->value.pass_through.operation,
restype, cst, jfunc->value.pass_through.operand);
}
if (!cst || !is_gimple_ip_invariant (cst))
lat->type = IPA_BOTTOM;
lat->constant = cst;
}
else if (jfunc->type == IPA_JF_ANCESTOR)
{
struct ipcp_lattice *caller_lat;
tree t;
caller_lat = ipcp_get_lattice (info, jfunc->value.ancestor.formal_id);
lat->type = caller_lat->type;
if (caller_lat->type != IPA_CONST_VALUE)
return;
if (TREE_CODE (caller_lat->constant) != ADDR_EXPR)
{
/* This can happen when the constant is a NULL pointer. */
lat->type = IPA_BOTTOM;
return;
}
t = TREE_OPERAND (caller_lat->constant, 0);
t = build_ref_for_offset (EXPR_LOCATION (t), t,
jfunc->value.ancestor.offset,
jfunc->value.ancestor.type, NULL, false);
lat->constant = build_fold_addr_expr (t);
}
else
lat->type = IPA_BOTTOM;
}
/* True when OLD_LAT and NEW_LAT values are not the same. */
static bool
ipcp_lattice_changed (struct ipcp_lattice *old_lat,
struct ipcp_lattice *new_lat)
{
if (old_lat->type == new_lat->type)
{
if (!ipcp_lat_is_const (old_lat))
return false;
if (ipcp_lats_are_equal (old_lat, new_lat))
return false;
}
return true;
}
/* Print all ipcp_lattices of all functions to F. */
static void
ipcp_print_all_lattices (FILE * f)
{
struct cgraph_node *node;
int i, count;
fprintf (f, "\nLattice:\n");
for (node = cgraph_nodes; node; node = node->next)
{
struct ipa_node_params *info;
if (!node->analyzed)
continue;
info = IPA_NODE_REF (node);
fprintf (f, " Node: %s:\n", cgraph_node_name (node));
count = ipa_get_param_count (info);
for (i = 0; i < count; i++)
{
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
fprintf (f, " param [%d]: ", i);
if (lat->type == IPA_CONST_VALUE)
{
tree cst = lat->constant;
fprintf (f, "type is CONST ");
print_generic_expr (f, cst, 0);
if (TREE_CODE (cst) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (cst, 0)) == CONST_DECL)
{
fprintf (f, " -> ");
print_generic_expr (f, DECL_INITIAL (TREE_OPERAND (cst, 0)),
0);
}
}
else if (lat->type == IPA_TOP)
fprintf (f, "type is TOP");
else
fprintf (f, "type is BOTTOM");
if (ipa_param_cannot_devirtualize_p (info, i))
fprintf (f, " - cannot_devirtualize set\n");
else if (ipa_param_types_vec_empty (info, i))
fprintf (f, " - type list empty\n");
else
fprintf (f, "\n");
}
}
}
/* Return true if ipcp algorithms would allow cloning NODE. */
static bool
ipcp_versionable_function_p (struct cgraph_node *node)
{
struct cgraph_edge *edge;
/* There are a number of generic reasons functions cannot be versioned. We
also cannot remove parameters if there are type attributes such as fnspec
present. */
if (!inline_summary (node)->versionable
|| TYPE_ATTRIBUTES (TREE_TYPE (node->decl)))
return false;
/* Removing arguments doesn't work if the function takes varargs
or use __builtin_apply_args. */
for (edge = node->callees; edge; edge = edge->next_callee)
{
tree t = edge->callee->decl;
if (DECL_BUILT_IN_CLASS (t) == BUILT_IN_NORMAL
&& (DECL_FUNCTION_CODE (t) == BUILT_IN_APPLY_ARGS
|| DECL_FUNCTION_CODE (t) == BUILT_IN_VA_START))
return false;
}
return true;
}
/* Return true if this NODE is viable candidate for cloning. */
static bool
ipcp_cloning_candidate_p (struct cgraph_node *node)
{
int n_calls = 0;
int n_hot_calls = 0;
gcov_type direct_call_sum = 0;
struct cgraph_edge *e;
/* We never clone functions that are not visible from outside.
FIXME: in future we should clone such functions when they are called with
different constants, but current ipcp implementation is not good on this.
*/
if (cgraph_only_called_directly_p (node) || !node->analyzed)
return false;
/* When function address is taken, we are pretty sure it will be called in hidden way. */
if (node->address_taken)
{
if (dump_file)
fprintf (dump_file, "Not considering %s for cloning; address is taken.\n",
cgraph_node_name (node));
return false;
}
if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
{
if (dump_file)
fprintf (dump_file, "Not considering %s for cloning; body is overwritable.\n",
cgraph_node_name (node));
return false;
}
if (!ipcp_versionable_function_p (node))
{
if (dump_file)
fprintf (dump_file, "Not considering %s for cloning; body is not versionable.\n",
cgraph_node_name (node));
return false;
}
for (e = node->callers; e; e = e->next_caller)
{
direct_call_sum += e->count;
n_calls ++;
if (cgraph_maybe_hot_edge_p (e))
n_hot_calls ++;
}
if (!n_calls)
{
if (dump_file)
fprintf (dump_file, "Not considering %s for cloning; no direct calls.\n",
cgraph_node_name (node));
return false;
}
if (inline_summary (node)->self_size < n_calls)
{
if (dump_file)
fprintf (dump_file, "Considering %s for cloning; code would shrink.\n",
cgraph_node_name (node));
return true;
}
if (!flag_ipa_cp_clone)
{
if (dump_file)
fprintf (dump_file, "Not considering %s for cloning; -fipa-cp-clone disabled.\n",
cgraph_node_name (node));
return false;
}
if (!optimize_function_for_speed_p (DECL_STRUCT_FUNCTION (node->decl)))
{
if (dump_file)
fprintf (dump_file, "Not considering %s for cloning; optimizing it for size.\n",
cgraph_node_name (node));
return false;
}
/* When profile is available and function is hot, propagate into it even if
calls seems cold; constant propagation can improve function's speed
significantly. */
if (max_count)
{
if (direct_call_sum > node->count * 90 / 100)
{
if (dump_file)
fprintf (dump_file, "Considering %s for cloning; usually called directly.\n",
cgraph_node_name (node));
return true;
}
}
if (!n_hot_calls)
{
if (dump_file)
fprintf (dump_file, "Not considering %s for cloning; no hot calls.\n",
cgraph_node_name (node));
return false;
}
if (dump_file)
fprintf (dump_file, "Considering %s for cloning.\n",
cgraph_node_name (node));
return true;
}
/* Mark parameter with index I of function described by INFO as unsuitable for
devirtualization. Return true if it has already been marked so. */
static bool
ipa_set_param_cannot_devirtualize (struct ipa_node_params *info, int i)
{
bool ret = info->params[i].cannot_devirtualize;
info->params[i].cannot_devirtualize = true;
if (info->params[i].types)
VEC_free (tree, heap, info->params[i].types);
return ret;
}
/* Initialize ipcp_lattices array. The lattices corresponding to supported
types (integers, real types and Fortran constants defined as const_decls)
are initialized to IPA_TOP, the rest of them to IPA_BOTTOM. */
static void
ipcp_initialize_node_lattices (struct cgraph_node *node)
{
int i;
struct ipa_node_params *info = IPA_NODE_REF (node);
enum ipa_lattice_type type;
if (ipa_is_called_with_var_arguments (info))
type = IPA_BOTTOM;
else if (node->local.local)
type = IPA_TOP;
/* When cloning is allowed, we can assume that externally visible functions
are not called. We will compensate this by cloning later. */
else if (ipcp_cloning_candidate_p (node))
type = IPA_TOP, n_cloning_candidates ++;
else
type = IPA_BOTTOM;
for (i = 0; i < ipa_get_param_count (info) ; i++)
{
ipcp_get_lattice (info, i)->type = type;
if (type == IPA_BOTTOM)
ipa_set_param_cannot_devirtualize (info, i);
}
}
/* Build a constant tree with type TREE_TYPE and value according to LAT.
Return the tree, or, if it is not possible to convert such value
to TREE_TYPE, NULL. */
static tree
build_const_val (struct ipcp_lattice *lat, tree tree_type)
{
tree val;
gcc_assert (ipcp_lat_is_const (lat));
val = lat->constant;
if (!useless_type_conversion_p (tree_type, TREE_TYPE (val)))
{
if (fold_convertible_p (tree_type, val))
return fold_build1 (NOP_EXPR, tree_type, val);
else if (TYPE_SIZE (tree_type) == TYPE_SIZE (TREE_TYPE (val)))
return fold_build1 (VIEW_CONVERT_EXPR, tree_type, val);
else
return NULL;
}
return val;
}
/* Compute the proper scale for NODE. It is the ratio between the number of
direct calls (represented on the incoming cgraph_edges) and sum of all
invocations of NODE (represented as count in cgraph_node).
FIXME: This code is wrong. Since the callers can be also clones and
the clones are not scaled yet, the sums gets unrealistically high.
To properly compute the counts, we would need to do propagation across
callgraph (as external call to A might imply call to non-cloned B
if A's clone calls cloned B). */
static void
ipcp_compute_node_scale (struct cgraph_node *node)
{
gcov_type sum;
struct cgraph_edge *cs;
sum = 0;
/* Compute sum of all counts of callers. */
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
sum += cs->count;
/* Work around the unrealistically high sum problem. We just don't want
the non-cloned body to have negative or very low frequency. Since
majority of execution time will be spent in clones anyway, this should
give good enough profile. */
if (sum > node->count * 9 / 10)
sum = node->count * 9 / 10;
if (node->count == 0)
ipcp_set_node_scale (node, 0);
else
ipcp_set_node_scale (node, sum * REG_BR_PROB_BASE / node->count);
}
/* Return true if there are some formal parameters whose value is IPA_TOP (in
the whole compilation unit). Change their values to IPA_BOTTOM, since they
most probably get their values from outside of this compilation unit. */
static bool
ipcp_change_tops_to_bottom (void)
{
int i, count;
struct cgraph_node *node;
bool prop_again;
prop_again = false;
for (node = cgraph_nodes; node; node = node->next)
{
struct ipa_node_params *info = IPA_NODE_REF (node);
count = ipa_get_param_count (info);
for (i = 0; i < count; i++)
{
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
if (lat->type == IPA_TOP)
{
prop_again = true;
if (dump_file)
{
fprintf (dump_file, "Forcing param ");
print_generic_expr (dump_file, ipa_get_param (info, i), 0);
fprintf (dump_file, " of node %s to bottom.\n",
cgraph_node_name (node));
}
lat->type = IPA_BOTTOM;
}
if (!ipa_param_cannot_devirtualize_p (info, i)
&& ipa_param_types_vec_empty (info, i))
{
prop_again = true;
ipa_set_param_cannot_devirtualize (info, i);
if (dump_file)
{
fprintf (dump_file, "Marking param ");
print_generic_expr (dump_file, ipa_get_param (info, i), 0);
fprintf (dump_file, " of node %s as unusable for "
"devirtualization.\n",
cgraph_node_name (node));
}
}
}
}
return prop_again;
}
/* Insert BINFO to the list of known types of parameter number I of the
function described by CALLEE_INFO. Return true iff the type information
associated with the callee parameter changed in any way. */
static bool
ipcp_add_param_type (struct ipa_node_params *callee_info, int i, tree binfo)
{
int j, count;
if (ipa_param_cannot_devirtualize_p (callee_info, i))
return false;
if (callee_info->params[i].types)
{
count = VEC_length (tree, callee_info->params[i].types);
for (j = 0; j < count; j++)
if (VEC_index (tree, callee_info->params[i].types, j) == binfo)
return false;
}
if (VEC_length (tree, callee_info->params[i].types)
== (unsigned) PARAM_VALUE (PARAM_DEVIRT_TYPE_LIST_SIZE))
return !ipa_set_param_cannot_devirtualize (callee_info, i);
VEC_safe_push (tree, heap, callee_info->params[i].types, binfo);
return true;
}
/* Copy known types information for parameter number CALLEE_IDX of CALLEE_INFO
from a parameter of CALLER_INFO as described by JF. Return true iff the
type information changed in any way. JF must be a pass-through or an
ancestor jump function. */
static bool
ipcp_copy_types (struct ipa_node_params *caller_info,
struct ipa_node_params *callee_info,
int callee_idx, struct ipa_jump_func *jf)
{
int caller_idx, j, count;
bool res;
if (ipa_param_cannot_devirtualize_p (callee_info, callee_idx))
return false;
if (jf->type == IPA_JF_PASS_THROUGH)
{
if (jf->value.pass_through.operation != NOP_EXPR)
{
ipa_set_param_cannot_devirtualize (callee_info, callee_idx);
return true;
}
caller_idx = jf->value.pass_through.formal_id;
}
else
caller_idx = jf->value.ancestor.formal_id;
if (ipa_param_cannot_devirtualize_p (caller_info, caller_idx))
{
ipa_set_param_cannot_devirtualize (callee_info, callee_idx);
return true;
}
if (!caller_info->params[caller_idx].types)
return false;
res = false;
count = VEC_length (tree, caller_info->params[caller_idx].types);
for (j = 0; j < count; j++)
{
tree binfo = VEC_index (tree, caller_info->params[caller_idx].types, j);
if (jf->type == IPA_JF_ANCESTOR)
{
binfo = get_binfo_at_offset (binfo, jf->value.ancestor.offset,
jf->value.ancestor.type);
if (!binfo)
{
ipa_set_param_cannot_devirtualize (callee_info, callee_idx);
return true;
}
}
res |= ipcp_add_param_type (callee_info, callee_idx, binfo);
}
return res;
}
/* Propagate type information for parameter of CALLEE_INFO number I as
described by JF. CALLER_INFO describes the caller. Return true iff the
type information changed in any way. */
static bool
ipcp_propagate_types (struct ipa_node_params *caller_info,
struct ipa_node_params *callee_info,
struct ipa_jump_func *jf, int i)
{
switch (jf->type)
{
case IPA_JF_UNKNOWN:
case IPA_JF_CONST_MEMBER_PTR:
case IPA_JF_CONST:
break;
case IPA_JF_KNOWN_TYPE:
return ipcp_add_param_type (callee_info, i, jf->value.base_binfo);
case IPA_JF_PASS_THROUGH:
case IPA_JF_ANCESTOR:
return ipcp_copy_types (caller_info, callee_info, i, jf);
}
/* If we reach this we cannot use this parameter for devirtualization. */
return !ipa_set_param_cannot_devirtualize (callee_info, i);
}
/* Interprocedural analysis. The algorithm propagates constants from the
caller's parameters to the callee's arguments. */
static void
ipcp_propagate_stage (void)
{
int i;
struct ipcp_lattice inc_lat = { IPA_BOTTOM, NULL };
struct ipcp_lattice new_lat = { IPA_BOTTOM, NULL };
struct ipcp_lattice *dest_lat;
struct cgraph_edge *cs;
struct ipa_jump_func *jump_func;
struct ipa_func_list *wl;
int count;
ipa_check_create_node_params ();
ipa_check_create_edge_args ();
/* Initialize worklist to contain all functions. */
wl = ipa_init_func_list ();
while (wl)
{
struct cgraph_node *node = ipa_pop_func_from_list (&wl);
struct ipa_node_params *info = IPA_NODE_REF (node);
for (cs = node->callees; cs; cs = cs->next_callee)
{
struct ipa_node_params *callee_info = IPA_NODE_REF (cs->callee);
struct ipa_edge_args *args = IPA_EDGE_REF (cs);
if (ipa_is_called_with_var_arguments (callee_info)
|| !cs->callee->analyzed
|| ipa_is_called_with_var_arguments (callee_info))
continue;
count = ipa_get_cs_argument_count (args);
for (i = 0; i < count; i++)
{
jump_func = ipa_get_ith_jump_func (args, i);
ipcp_lattice_from_jfunc (info, &inc_lat, jump_func);
dest_lat = ipcp_get_lattice (callee_info, i);
ipa_lattice_meet (&new_lat, &inc_lat, dest_lat);
if (ipcp_lattice_changed (&new_lat, dest_lat))
{
dest_lat->type = new_lat.type;
dest_lat->constant = new_lat.constant;
ipa_push_func_to_list (&wl, cs->callee);
}
if (ipcp_propagate_types (info, callee_info, jump_func, i))
ipa_push_func_to_list (&wl, cs->callee);
}
}
}
}
/* Call the constant propagation algorithm and re-call it if necessary
(if there are undetermined values left). */
static void
ipcp_iterate_stage (void)
{
struct cgraph_node *node;
n_cloning_candidates = 0;
if (dump_file)
fprintf (dump_file, "\nIPA iterate stage:\n\n");
if (in_lto_p)
ipa_update_after_lto_read ();
for (node = cgraph_nodes; node; node = node->next)
{
ipcp_initialize_node_lattices (node);
ipcp_compute_node_scale (node);
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
ipcp_print_all_lattices (dump_file);
ipcp_function_scale_print (dump_file);
}
ipcp_propagate_stage ();
if (ipcp_change_tops_to_bottom ())
/* Some lattices have changed from IPA_TOP to IPA_BOTTOM.
This change should be propagated. */
{
gcc_assert (n_cloning_candidates);
ipcp_propagate_stage ();
}
if (dump_file)
{
fprintf (dump_file, "\nIPA lattices after propagation:\n");
ipcp_print_all_lattices (dump_file);
if (dump_flags & TDF_DETAILS)
ipcp_print_profile_data (dump_file);
}
}
/* Check conditions to forbid constant insertion to function described by
NODE. */
static inline bool
ipcp_node_modifiable_p (struct cgraph_node *node)
{
/* Once we will be able to do in-place replacement, we can be more
lax here. */
return ipcp_versionable_function_p (node);
}
/* Print count scale data structures. */
static void
ipcp_function_scale_print (FILE * f)
{
struct cgraph_node *node;
for (node = cgraph_nodes; node; node = node->next)
{
if (!node->analyzed)
continue;
fprintf (f, "printing scale for %s: ", cgraph_node_name (node));
fprintf (f, "value is " HOST_WIDE_INT_PRINT_DEC
" \n", (HOST_WIDE_INT) ipcp_get_node_scale (node));
}
}
/* Print counts of all cgraph nodes. */
static void
ipcp_print_func_profile_counts (FILE * f)
{
struct cgraph_node *node;
for (node = cgraph_nodes; node; node = node->next)
{
fprintf (f, "function %s: ", cgraph_node_name (node));
fprintf (f, "count is " HOST_WIDE_INT_PRINT_DEC
" \n", (HOST_WIDE_INT) node->count);
}
}
/* Print counts of all cgraph edges. */
static void
ipcp_print_call_profile_counts (FILE * f)
{
struct cgraph_node *node;
struct cgraph_edge *cs;
for (node = cgraph_nodes; node; node = node->next)
{
for (cs = node->callees; cs; cs = cs->next_callee)
{
fprintf (f, "%s -> %s ", cgraph_node_name (cs->caller),
cgraph_node_name (cs->callee));
fprintf (f, "count is " HOST_WIDE_INT_PRINT_DEC " \n",
(HOST_WIDE_INT) cs->count);
}
}
}
/* Print profile info for all functions. */
static void
ipcp_print_profile_data (FILE * f)
{
fprintf (f, "\nNODE COUNTS :\n");
ipcp_print_func_profile_counts (f);
fprintf (f, "\nCS COUNTS stage:\n");
ipcp_print_call_profile_counts (f);
}
/* Build and initialize ipa_replace_map struct according to LAT. This struct is
processed by versioning, which operates according to the flags set.
PARM_TREE is the formal parameter found to be constant. LAT represents the
constant. */
static struct ipa_replace_map *
ipcp_create_replace_map (tree parm_tree, struct ipcp_lattice *lat)
{
struct ipa_replace_map *replace_map;
tree const_val;
const_val = build_const_val (lat, TREE_TYPE (parm_tree));
if (const_val == NULL_TREE)
{
if (dump_file)
{
fprintf (dump_file, " const ");
print_generic_expr (dump_file, lat->constant, 0);
fprintf (dump_file, " can't be converted to param ");
print_generic_expr (dump_file, parm_tree, 0);
fprintf (dump_file, "\n");
}
return NULL;
}
replace_map = ggc_alloc_ipa_replace_map ();
if (dump_file)
{
fprintf (dump_file, " replacing param ");
print_generic_expr (dump_file, parm_tree, 0);
fprintf (dump_file, " with const ");
print_generic_expr (dump_file, const_val, 0);
fprintf (dump_file, "\n");
}
replace_map->old_tree = parm_tree;
replace_map->new_tree = const_val;
replace_map->replace_p = true;
replace_map->ref_p = false;
return replace_map;
}
/* Return true if this callsite should be redirected to the original callee
(instead of the cloned one). */
static bool
ipcp_need_redirect_p (struct cgraph_edge *cs)
{
struct ipa_node_params *orig_callee_info;
int i, count;
struct cgraph_node *node = cs->callee, *orig;
if (!n_cloning_candidates)
return false;
if ((orig = ipcp_get_orig_node (node)) != NULL)
node = orig;
if (ipcp_get_orig_node (cs->caller))
return false;
orig_callee_info = IPA_NODE_REF (node);
count = ipa_get_param_count (orig_callee_info);
for (i = 0; i < count; i++)
{
struct ipcp_lattice *lat = ipcp_get_lattice (orig_callee_info, i);
struct ipa_jump_func *jump_func;
jump_func = ipa_get_ith_jump_func (IPA_EDGE_REF (cs), i);
if ((ipcp_lat_is_const (lat)
&& jump_func->type != IPA_JF_CONST)
|| (!ipa_param_cannot_devirtualize_p (orig_callee_info, i)
&& !ipa_param_types_vec_empty (orig_callee_info, i)
&& jump_func->type != IPA_JF_CONST
&& jump_func->type != IPA_JF_KNOWN_TYPE))
return true;
}
return false;
}
/* Fix the callsites and the call graph after function cloning was done. */
static void
ipcp_update_callgraph (void)
{
struct cgraph_node *node;
for (node = cgraph_nodes; node; node = node->next)
if (node->analyzed && ipcp_node_is_clone (node))
{
bitmap args_to_skip = NULL;
struct cgraph_node *orig_node = ipcp_get_orig_node (node);
struct ipa_node_params *info = IPA_NODE_REF (orig_node);
int i, count = ipa_get_param_count (info);
struct cgraph_edge *cs, *next;
if (node->local.can_change_signature)
{
args_to_skip = BITMAP_ALLOC (NULL);
for (i = 0; i < count; i++)
{
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
/* We can proactively remove obviously unused arguments. */
if (!ipa_is_param_used (info, i))
{
bitmap_set_bit (args_to_skip, i);
continue;
}
if (lat->type == IPA_CONST_VALUE)
bitmap_set_bit (args_to_skip, i);
}
}
for (cs = node->callers; cs; cs = next)
{
next = cs->next_caller;
if (!ipcp_node_is_clone (cs->caller) && ipcp_need_redirect_p (cs))
{
if (dump_file)
fprintf (dump_file, "Redirecting edge %s/%i -> %s/%i "
"back to %s/%i.",
cgraph_node_name (cs->caller), cs->caller->uid,
cgraph_node_name (cs->callee), cs->callee->uid,
cgraph_node_name (orig_node), orig_node->uid);
cgraph_redirect_edge_callee (cs, orig_node);
}
}
}
}
/* Update profiling info for versioned functions and the functions they were
versioned from. */
static void
ipcp_update_profiling (void)
{
struct cgraph_node *node, *orig_node;
gcov_type scale, scale_complement;
struct cgraph_edge *cs;
for (node = cgraph_nodes; node; node = node->next)
{
if (ipcp_node_is_clone (node))
{
orig_node = ipcp_get_orig_node (node);
scale = ipcp_get_node_scale (orig_node);
node->count = orig_node->count * scale / REG_BR_PROB_BASE;
scale_complement = REG_BR_PROB_BASE - scale;
/* Negative scale complement can result from insane profile data
in which the total incoming edge counts in this module is
larger than the callee's entry count. The insane profile data
usually gets generated due to the following reasons:
1) in multithreaded programs, when profile data is dumped
to gcda files in gcov_exit, some other threads are still running.
The profile counters are dumped in bottom up order (call graph).
The caller's BB counters may still be updated while the callee's
counter data is already saved to disk.
2) Comdat functions: comdat functions' profile data are not
allocated in comdat. When a comdat callee function gets inlined
at some callsites after instrumentation, and the remaining calls
to this function resolves to a comdat copy in another module,
the profile counters for this function are split. This can
result in sum of incoming edge counts from this module being
larger than callee instance's entry count. */
if (scale_complement < 0 && flag_profile_correction)
scale_complement = 0;
orig_node->count =
orig_node->count * scale_complement / REG_BR_PROB_BASE;
for (cs = node->callees; cs; cs = cs->next_callee)
cs->count = cs->count * scale / REG_BR_PROB_BASE;
for (cs = orig_node->callees; cs; cs = cs->next_callee)
cs->count = cs->count * scale_complement / REG_BR_PROB_BASE;
}
}
}
/* If NODE was cloned, how much would program grow? */
static long
ipcp_estimate_growth (struct cgraph_node *node)
{
struct cgraph_edge *cs;
int redirectable_node_callers = 0;
int removable_args = 0;
bool need_original
= !cgraph_will_be_removed_from_program_if_no_direct_calls (node);
struct ipa_node_params *info;
int i, count;
int growth;
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
if (cs->caller == node || !ipcp_need_redirect_p (cs))
redirectable_node_callers++;
else
need_original = true;
/* If we will be able to fully replace original node, we never increase
program size. */
if (!need_original)
return 0;
info = IPA_NODE_REF (node);
count = ipa_get_param_count (info);
if (node->local.can_change_signature)
for (i = 0; i < count; i++)
{
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
/* We can proactively remove obviously unused arguments. */
if (!ipa_is_param_used (info, i))
removable_args++;
if (lat->type == IPA_CONST_VALUE)
removable_args++;
}
/* We make just very simple estimate of savings for removal of operand from
call site. Precise cost is difficult to get, as our size metric counts
constants and moves as free. Generally we are looking for cases that
small function is called very many times. */
growth = inline_summary (node)->self_size
- removable_args * redirectable_node_callers;
if (growth < 0)
return 0;
return growth;
}
/* Estimate cost of cloning NODE. */
static long
ipcp_estimate_cloning_cost (struct cgraph_node *node)
{
int freq_sum = 1;
gcov_type count_sum = 1;
struct cgraph_edge *e;
int cost;
cost = ipcp_estimate_growth (node) * 1000;
if (!cost)
{
if (dump_file)
fprintf (dump_file, "Versioning of %s will save code size\n",
cgraph_node_name (node));
return 0;
}
for (e = node->callers; e; e = e->next_caller)
if (!bitmap_bit_p (dead_nodes, e->caller->uid)
&& !ipcp_need_redirect_p (e))
{
count_sum += e->count;
freq_sum += e->frequency + 1;
}
if (max_count)
cost /= count_sum * 1000 / max_count + 1;
else
cost /= freq_sum * 1000 / REG_BR_PROB_BASE + 1;
if (dump_file)
fprintf (dump_file, "Cost of versioning %s is %i, (size: %i, freq: %i)\n",
cgraph_node_name (node), cost, inline_summary (node)->self_size,
freq_sum);
return cost + 1;
}
/* Walk indirect calls of NODE and if any polymorphic can be turned into a
direct one now, do so. */
static void
ipcp_process_devirtualization_opportunities (struct cgraph_node *node)
{
struct ipa_node_params *info = IPA_NODE_REF (node);
struct cgraph_edge *ie, *next_ie;
for (ie = node->indirect_calls; ie; ie = next_ie)
{
int param_index, types_count, j;
HOST_WIDE_INT token;
tree target, delta;
next_ie = ie->next_callee;
if (!ie->indirect_info->polymorphic)
continue;
param_index = ie->indirect_info->param_index;
if (param_index == -1
|| ipa_param_cannot_devirtualize_p (info, param_index)
|| ipa_param_types_vec_empty (info, param_index))
continue;
token = ie->indirect_info->otr_token;
target = NULL_TREE;
types_count = VEC_length (tree, info->params[param_index].types);
for (j = 0; j < types_count; j++)
{
tree binfo = VEC_index (tree, info->params[param_index].types, j);
tree d;
tree t = gimple_get_virt_method_for_binfo (token, binfo, &d, true);
if (!t)
{
target = NULL_TREE;
break;
}
else if (!target)
{
target = t;
delta = d;
}
else if (target != t || !tree_int_cst_equal (delta, d))
{
target = NULL_TREE;
break;
}
}
if (target)
ipa_make_edge_direct_to_target (ie, target, delta);
}
}
/* Return number of live constant parameters. */
static int
ipcp_const_param_count (struct cgraph_node *node)
{
int const_param = 0;
struct ipa_node_params *info = IPA_NODE_REF (node);
int count = ipa_get_param_count (info);
int i;
for (i = 0; i < count; i++)
{
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
if ((ipcp_lat_is_insertable (lat)
/* Do not count obviously unused arguments. */
&& ipa_is_param_used (info, i))
|| (!ipa_param_cannot_devirtualize_p (info, i)
&& !ipa_param_types_vec_empty (info, i)))
const_param++;
}
return const_param;
}
/* Given that a formal parameter of NODE given by INDEX is known to be constant
CST, try to find any indirect edges that can be made direct and make them
so. Note that INDEX is the number the parameter at the time of analyzing
parameter uses and parameter removals should not be considered for it. (In
fact, the parameter itself has just been removed.) */
static void
ipcp_discover_new_direct_edges (struct cgraph_node *node, int index, tree cst)
{
struct cgraph_edge *ie, *next_ie;
for (ie = node->indirect_calls; ie; ie = next_ie)
{
struct cgraph_indirect_call_info *ici = ie->indirect_info;
next_ie = ie->next_callee;
if (ici->param_index != index
|| ici->polymorphic)
continue;
ipa_make_edge_direct_to_target (ie, cst, NULL_TREE);
}
}
/* Propagate the constant parameters found by ipcp_iterate_stage()
to the function's code. */
static void
ipcp_insert_stage (void)
{
struct cgraph_node *node, *node1 = NULL;
int i;
VEC (cgraph_edge_p, heap) * redirect_callers;
VEC (ipa_replace_map_p,gc)* replace_trees;
int node_callers, count;
tree parm_tree;
struct ipa_replace_map *replace_param;
fibheap_t heap;
long overall_size = 0, new_size = 0;
long max_new_size;
ipa_check_create_node_params ();
ipa_check_create_edge_args ();
if (dump_file)
fprintf (dump_file, "\nIPA insert stage:\n\n");
dead_nodes = BITMAP_ALLOC (NULL);
for (node = cgraph_nodes; node; node = node->next)
if (node->analyzed)
{
if (node->count > max_count)
max_count = node->count;
overall_size += inline_summary (node)->self_size;
}
max_new_size = overall_size;
if (max_new_size < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS))
max_new_size = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS);
max_new_size = max_new_size * PARAM_VALUE (PARAM_IPCP_UNIT_GROWTH) / 100 + 1;
/* First collect all functions we proved to have constant arguments to
heap. */
heap = fibheap_new ();
for (node = cgraph_nodes; node; node = node->next)
{
struct ipa_node_params *info;
/* Propagation of the constant is forbidden in certain conditions. */
if (!node->analyzed || !ipcp_node_modifiable_p (node))
continue;
info = IPA_NODE_REF (node);
if (ipa_is_called_with_var_arguments (info))
continue;
if (ipcp_const_param_count (node))
node->aux = fibheap_insert (heap, ipcp_estimate_cloning_cost (node),
node);
}
/* Now clone in priority order until code size growth limits are met or
heap is emptied. */
while (!fibheap_empty (heap))
{
struct ipa_node_params *info;
int growth = 0;
bitmap args_to_skip;
struct cgraph_edge *cs;
node = (struct cgraph_node *)fibheap_extract_min (heap);
node->aux = NULL;
if (dump_file)
fprintf (dump_file, "considering function %s\n",
cgraph_node_name (node));
growth = ipcp_estimate_growth (node);
if (new_size + growth > max_new_size)
break;
if (growth
&& cgraph_optimize_for_size_p (node))
{
if (dump_file)
fprintf (dump_file, "Not versioning, cold code would grow");
continue;
}
info = IPA_NODE_REF (node);
count = ipa_get_param_count (info);
replace_trees = VEC_alloc (ipa_replace_map_p, gc, 1);
if (node->local.can_change_signature)
args_to_skip = BITMAP_GGC_ALLOC ();
else
args_to_skip = NULL;
for (i = 0; i < count; i++)
{
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
parm_tree = ipa_get_param (info, i);
/* We can proactively remove obviously unused arguments. */
if (!ipa_is_param_used (info, i))
{
if (args_to_skip)
bitmap_set_bit (args_to_skip, i);
continue;
}
if (lat->type == IPA_CONST_VALUE)
{
replace_param =
ipcp_create_replace_map (parm_tree, lat);
if (replace_param == NULL)
break;
VEC_safe_push (ipa_replace_map_p, gc, replace_trees, replace_param);
if (args_to_skip)
bitmap_set_bit (args_to_skip, i);
}
}
if (i < count)
{
if (dump_file)
fprintf (dump_file, "Not versioning, some parameters couldn't be replaced");
continue;
}
new_size += growth;
/* Look if original function becomes dead after cloning. */
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
if (cs->caller == node || ipcp_need_redirect_p (cs))
break;
if (!cs && cgraph_will_be_removed_from_program_if_no_direct_calls (node))
bitmap_set_bit (dead_nodes, node->uid);
/* Compute how many callers node has. */
node_callers = 0;
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
node_callers++;
redirect_callers = VEC_alloc (cgraph_edge_p, heap, node_callers);
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
if (!cs->indirect_inlining_edge)
VEC_quick_push (cgraph_edge_p, redirect_callers, cs);
/* Redirecting all the callers of the node to the
new versioned node. */
node1 =
cgraph_create_virtual_clone (node, redirect_callers, replace_trees,
args_to_skip, "constprop");
args_to_skip = NULL;
VEC_free (cgraph_edge_p, heap, redirect_callers);
replace_trees = NULL;
if (node1 == NULL)
continue;
ipcp_process_devirtualization_opportunities (node1);
if (dump_file)
fprintf (dump_file, "versioned function %s with growth %i, overall %i\n",
cgraph_node_name (node), (int)growth, (int)new_size);
ipcp_init_cloned_node (node, node1);
info = IPA_NODE_REF (node);
for (i = 0; i < count; i++)
{
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
if (lat->type == IPA_CONST_VALUE)
ipcp_discover_new_direct_edges (node1, i, lat->constant);
}
if (dump_file)
dump_function_to_file (node1->decl, dump_file, dump_flags);
for (cs = node->callees; cs; cs = cs->next_callee)
if (cs->callee->aux)
{
fibheap_delete_node (heap, (fibnode_t) cs->callee->aux);
cs->callee->aux = fibheap_insert (heap,
ipcp_estimate_cloning_cost (cs->callee),
cs->callee);
}
}
while (!fibheap_empty (heap))
{
if (dump_file)
fprintf (dump_file, "skipping function %s\n",
cgraph_node_name (node));
node = (struct cgraph_node *) fibheap_extract_min (heap);
node->aux = NULL;
}
fibheap_delete (heap);
BITMAP_FREE (dead_nodes);
ipcp_update_callgraph ();
ipcp_update_profiling ();
}
/* The IPCP driver. */
static unsigned int
ipcp_driver (void)
{
cgraph_remove_unreachable_nodes (true,dump_file);
if (dump_file)
{
fprintf (dump_file, "\nIPA structures before propagation:\n");
if (dump_flags & TDF_DETAILS)
ipa_print_all_params (dump_file);
ipa_print_all_jump_functions (dump_file);
}
ipa_check_create_node_params ();
ipa_check_create_edge_args ();
/* 2. Do the interprocedural propagation. */
ipcp_iterate_stage ();
/* 3. Insert the constants found to the functions. */
ipcp_insert_stage ();
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "\nProfiling info after insert stage:\n");
ipcp_print_profile_data (dump_file);
}
/* Free all IPCP structures. */
ipa_free_all_structures_after_ipa_cp ();
if (dump_file)
fprintf (dump_file, "\nIPA constant propagation end\n");
return 0;
}
/* Initialization and computation of IPCP data structures. This is the initial
intraprocedural analysis of functions, which gathers information to be
propagated later on. */
static void
ipcp_generate_summary (void)
{
struct cgraph_node *node;
if (dump_file)
fprintf (dump_file, "\nIPA constant propagation start:\n");
ipa_register_cgraph_hooks ();
for (node = cgraph_nodes; node; node = node->next)
if (node->analyzed)
{
/* Unreachable nodes should have been eliminated before ipcp. */
gcc_assert (node->needed || node->reachable);
inline_summary (node)->versionable = tree_versionable_function_p (node->decl);
ipa_analyze_node (node);
}
}
/* Write ipcp summary for nodes in SET. */
static void
ipcp_write_summary (cgraph_node_set set,
varpool_node_set vset ATTRIBUTE_UNUSED)
{
ipa_prop_write_jump_functions (set);
}
/* Read ipcp summary. */
static void
ipcp_read_summary (void)
{
ipa_prop_read_jump_functions ();
}
/* Gate for IPCP optimization. */
static bool
cgraph_gate_cp (void)
{
/* FIXME: We should remove the optimize check after we ensure we never run
IPA passes when not optimizing. */
return flag_ipa_cp && optimize;
}
struct ipa_opt_pass_d pass_ipa_cp =
{
{
IPA_PASS,
"cp", /* name */
cgraph_gate_cp, /* gate */
ipcp_driver, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_IPA_CONSTANT_PROP, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_cgraph | TODO_dump_func |
TODO_remove_functions | TODO_ggc_collect /* todo_flags_finish */
},
ipcp_generate_summary, /* generate_summary */
ipcp_write_summary, /* write_summary */
ipcp_read_summary, /* read_summary */
NULL, /* write_optimization_summary */
NULL, /* read_optimization_summary */
NULL, /* stmt_fixup */
0, /* TODOs */
NULL, /* function_transform */
NULL, /* variable_transform */
};
|