-
Notifications
You must be signed in to change notification settings - Fork 1.5k
/
smt_internalizer.cpp
1770 lines (1620 loc) · 67.7 KB
/
smt_internalizer.cpp
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) 2006 Microsoft Corporation
Module Name:
smt_internalizer.cpp
Abstract:
<abstract>
Author:
Leonardo de Moura (leonardo) 2008-02-20.
Revision History:
--*/
#include "smt/smt_context.h"
#include "ast/expr_stat.h"
#include "ast/ast_pp.h"
#include "ast/ast_ll_pp.h"
#include "ast/ast_smt2_pp.h"
#include "smt/smt_model_finder.h"
#include "ast/for_each_expr.h"
namespace smt {
/**
\brief Return true if the expression is viewed as a logical gate.
*/
static bool is_gate(ast_manager const & m, expr * n) {
if (is_app(n) && to_app(n)->get_family_id() == m.get_basic_family_id()) {
switch (to_app(n)->get_decl_kind()) {
case OP_AND:
case OP_OR:
case OP_ITE:
return true;
case OP_EQ:
return m.is_bool(to_app(n)->get_arg(0));
default:
return false;
}
}
return false;
}
#define White 0
#define Grey 1
#define Black 2
static char get_color(char_vector & tcolors, char_vector & fcolors, expr * n, bool gate_ctx) {
char_vector & colors = gate_ctx ? tcolors : fcolors;
if (colors.size() > n->get_id())
return colors[n->get_id()];
return White;
}
static void set_color(char_vector & tcolors, char_vector & fcolors, expr * n, bool gate_ctx, char color) {
char_vector & colors = gate_ctx ? tcolors : fcolors;
if (colors.size() <= n->get_id()) {
colors.resize(n->get_id()+1, White);
}
colors[n->get_id()] = color;
}
/**
\brief Return the foreign descendants of n. That is, the descendants of n where the family_id is different from fid.
For example the descendants of (+ a (+ (f b) (* 2 (h (+ c d))))) are:
- a
- (f b)
- (h (+ c d))
*/
static void get_foreign_descendants(app * n, family_id fid, ptr_buffer<expr> & descendants) {
SASSERT(n->get_family_id() == fid);
SASSERT(fid != null_family_id);
ptr_buffer<expr> todo;
todo.push_back(n);
ast_mark visited;
while (!todo.empty()) {
expr * curr = todo.back();
todo.pop_back();
if (visited.is_marked(n)) {
continue;
}
visited.mark(n, true);
if (!is_app(curr) || to_app(curr)->get_family_id() != fid) {
descendants.push_back(curr);
continue;
}
SASSERT(is_app(curr));
SASSERT(to_app(curr)->get_family_id() == fid);
unsigned j = to_app(curr)->get_num_args();
while (j > 0) {
--j;
todo.push_back(to_app(curr)->get_arg(j));
}
}
}
void context::ts_visit_child(expr * n, bool gate_ctx, svector<expr_bool_pair> & todo, bool & visited) {
if (get_color(tcolors, fcolors, n, gate_ctx) == White) {
todo.push_back(expr_bool_pair(n, gate_ctx));
visited = false;
}
}
bool context::ts_visit_children(expr * n, bool gate_ctx, svector<expr_bool_pair> & todo) {
if (is_quantifier(n))
return true;
if (!should_internalize_rec(n))
return true;
SASSERT(is_app(n));
if (m.is_bool(n)) {
if (b_internalized(n))
return true;
}
else {
if (e_internalized(n))
return true;
}
bool visited = true;
family_id fid = to_app(n)->get_family_id();
theory * th = m_theories.get_plugin(fid);
bool def_int = th == nullptr || th->default_internalizer();
if (!def_int) {
ptr_buffer<expr> descendants;
get_foreign_descendants(to_app(n), fid, descendants);
for (expr * arg : descendants) {
ts_visit_child(arg, false, todo, visited);
}
return visited;
}
SASSERT(def_int);
if (m.is_term_ite(n)) {
ts_visit_child(to_app(n)->get_arg(0), true, todo, visited);
ts_visit_child(to_app(n)->get_arg(1), false, todo, visited);
ts_visit_child(to_app(n)->get_arg(2), false, todo, visited);
return visited;
}
bool new_gate_ctx = m.is_bool(n) && (is_gate(m, n) || m.is_not(n));
unsigned j = to_app(n)->get_num_args();
while (j > 0) {
--j;
expr * arg = to_app(n)->get_arg(j);
ts_visit_child(arg, new_gate_ctx, todo, visited);
}
return visited;
}
void context::top_sort_expr(expr* const* exprs, unsigned num_exprs, svector<expr_bool_pair> & sorted_exprs) {
tcolors.reset();
fcolors.reset();
while (!ts_todo.empty()) {
expr_bool_pair & p = ts_todo.back();
expr * curr = p.first;
bool gate_ctx = p.second;
switch (get_color(tcolors, fcolors, curr, gate_ctx)) {
case White:
set_color(tcolors, fcolors, curr, gate_ctx, Grey);
ts_visit_children(curr, gate_ctx, ts_todo);
break;
case Grey: {
SASSERT(ts_visit_children(curr, gate_ctx, ts_todo));
set_color(tcolors, fcolors, curr, gate_ctx, Black);
auto end = exprs + num_exprs;
if (std::find(exprs, end, curr) == end && !m.is_not(curr) && should_internalize_rec(curr))
sorted_exprs.push_back(expr_bool_pair(curr, gate_ctx));
break;
}
case Black:
ts_todo.pop_back();
break;
default:
UNREACHABLE();
}
}
}
#define DEEP_EXPR_THRESHOLD 1024
bool context::should_internalize_rec(expr* e) const {
return !is_app(e) ||
!m.is_bool(e) ||
to_app(e)->get_family_id() == null_family_id ||
to_app(e)->get_family_id() == m.get_basic_family_id();
}
void context::internalize_deep(expr* const* exprs, unsigned num_exprs) {
ts_todo.reset();
for (unsigned i = 0; i < num_exprs; ++i) {
expr * n = exprs[i];
if (!e_internalized(n) && ::get_depth(n) > DEEP_EXPR_THRESHOLD && should_internalize_rec(n)) {
// if the expression is deep, then execute topological sort to avoid
// stack overflow.
// a caveat is that theory internalizers do rely on recursive descent so
// internalization over these follows top-down
TRACE("deep_internalize", tout << "expression is deep: #" << n->get_id() << "\n" << mk_ll_pp(n, m););
ts_todo.push_back(expr_bool_pair(n, true));
}
}
svector<expr_bool_pair> sorted_exprs;
top_sort_expr(exprs, num_exprs, sorted_exprs);
TRACE("deep_internalize", for (auto & kv : sorted_exprs) tout << "#" << kv.first->get_id() << " " << kv.second << "\n"; );
for (auto & kv : sorted_exprs) {
expr* e = kv.first;
SASSERT(should_internalize_rec(e));
internalize_rec(e, kv.second);
}
}
void context::internalize_deep(expr* n) {
expr * v[1] = { n };
internalize_deep(v, 1);
}
/**
\brief Internalize an expression asserted into the logical context using the given proof as a justification.
\remark pr is 0 if proofs are disabled.
*/
void context::internalize_assertion(expr * n, proof * pr, unsigned generation) {
TRACE("internalize_assertion", tout << mk_pp(n, m) << "\n";);
TRACE("internalize_assertion_ll", tout << mk_ll_pp(n, m) << "\n";);
TRACE("generation", tout << "generation: " << m_generation << "\n";);
TRACE("incompleteness_bug", tout << "[internalize-assertion]: #" << n->get_id() << "\n";);
flet<unsigned> l(m_generation, generation);
m_stats.m_max_generation = std::max(m_generation, m_stats.m_max_generation);
internalize_deep(n);
SASSERT(m.is_bool(n));
if (is_gate(m, n)) {
switch(to_app(n)->get_decl_kind()) {
case OP_AND: {
for (expr * arg : *to_app(n)) {
internalize_rec(arg, true);
literal lit = get_literal(arg);
mk_root_clause(1, &lit, pr);
}
break;
}
case OP_OR: {
literal_buffer lits;
for (expr * arg : *to_app(n)) {
internalize_rec(arg, true);
lits.push_back(get_literal(arg));
}
mk_root_clause(lits.size(), lits.c_ptr(), pr);
add_or_rel_watches(to_app(n));
break;
}
case OP_EQ: {
expr * lhs = to_app(n)->get_arg(0);
expr * rhs = to_app(n)->get_arg(1);
internalize_rec(lhs, true);
internalize_rec(rhs, true);
literal l1 = get_literal(lhs);
literal l2 = get_literal(rhs);
mk_root_clause(l1, ~l2, pr);
mk_root_clause(~l1, l2, pr);
break;
}
case OP_ITE: {
expr * c = to_app(n)->get_arg(0);
expr * t = to_app(n)->get_arg(1);
expr * e = to_app(n)->get_arg(2);
internalize_rec(c, true);
internalize_rec(t, true);
internalize_rec(e, true);
literal cl = get_literal(c);
literal tl = get_literal(t);
literal el = get_literal(e);
mk_root_clause(~cl, tl, pr);
mk_root_clause(cl, el, pr);
add_ite_rel_watches(to_app(n));
break;
}
default:
UNREACHABLE();
}
mark_as_relevant(n);
}
else if (m.is_distinct(n)) {
assert_distinct(to_app(n), pr);
mark_as_relevant(n);
}
else {
assert_default(n, pr);
}
}
void context::assert_default(expr * n, proof * pr) {
internalize(n, true);
literal l = get_literal(n);
if (l == false_literal) {
set_conflict(mk_justification(justification_proof_wrapper(*this, pr)));
}
else {
justification* j = mk_justification(justification_proof_wrapper(*this, pr));
m_clause_proof.add(l, CLS_AUX, j);
assign(l, j);
mark_as_relevant(l);
}
}
#define DISTINCT_SZ_THRESHOLD 32
void context::assert_distinct(app * n, proof * pr) {
TRACE("assert_distinct", tout << mk_pp(n, m) << "\n";);
unsigned num_args = n->get_num_args();
if (num_args == 0 || num_args <= DISTINCT_SZ_THRESHOLD || m.proofs_enabled()) {
assert_default(n, pr);
return;
}
sort * s = m.get_sort(n->get_arg(0));
sort_ref u(m.mk_fresh_sort("distinct-elems"), m);
func_decl_ref f(m.mk_fresh_func_decl("distinct-aux-f", "", 1, &s, u), m);
for (expr * arg : *n) {
app_ref fapp(m.mk_app(f, arg), m);
app_ref val(m.mk_fresh_const("unique-value", u), m);
enode * e = mk_enode(val, false, false, true);
e->mark_as_interpreted();
app_ref eq(m.mk_eq(fapp, val), m);
TRACE("assert_distinct", tout << "eq: " << mk_pp(eq, m) << "\n";);
assert_default(eq, nullptr);
mark_as_relevant(eq.get());
// TODO: we may want to hide the auxiliary values val and the function f from the model.
}
}
void context::internalize(expr * n, bool gate_ctx, unsigned generation) {
flet<unsigned> l(m_generation, generation);
m_stats.m_max_generation = std::max(m_generation, m_stats.m_max_generation);
internalize_rec(n, gate_ctx);
}
void context::ensure_internalized(expr* e) {
if (!e_internalized(e)) {
internalize(e, false);
}
}
/**
\brief Internalize the given expression into the logical context.
- gate_ctx is true if the expression is in the context of a logical gate.
*/
void context::internalize(expr * n, bool gate_ctx) {
internalize_deep(n);
internalize_rec(n, gate_ctx);
}
void context::internalize(expr* const* exprs, unsigned num_exprs, bool gate_ctx) {
internalize_deep(exprs, num_exprs);
for (unsigned i = 0; i < num_exprs; ++i) {
internalize_rec(exprs[i], gate_ctx);
}
}
void context::internalize_rec(expr * n, bool gate_ctx) {
TRACE("internalize", tout << "internalizing:\n" << mk_pp(n, m) << "\n";);
TRACE("internalize_bug", tout << "internalizing:\n" << mk_bounded_pp(n, m) << "\n";);
if (is_var(n)) {
throw default_exception("Formulas should not contain unbound variables");
}
if (m.is_bool(n)) {
SASSERT(is_quantifier(n) || is_app(n));
internalize_formula(n, gate_ctx);
}
else if (is_lambda(n)) {
internalize_lambda(to_quantifier(n));
}
else {
SASSERT(is_app(n));
SASSERT(!gate_ctx);
internalize_term(to_app(n));
}
}
/**
\brief Internalize the given formula into the logical context.
*/
void context::internalize_formula(expr * n, bool gate_ctx) {
TRACE("internalize_bug", tout << "internalize formula: #" << n->get_id() << ", gate_ctx: " << gate_ctx << "\n" << mk_pp(n, m) << "\n";);
SASSERT(m.is_bool(n));
if (m.is_true(n) || m.is_false(n))
return;
if (m.is_not(n) && gate_ctx) {
// a boolean variable does not need to be created if n a NOT gate is in
// the context of a gate.
internalize_rec(to_app(n)->get_arg(0), true);
return;
}
if (b_internalized(n)) {
// n was already internalized as a boolean.
bool_var v = get_bool_var(n);
TRACE("internalize_bug", tout << "#" << n->get_id() << " already has bool_var v" << v << "\n";);
// n was already internalized as boolean, but an enode was
// not associated with it. So, an enode is necessary, if
// n is not in the context of a gate and is an application.
if (!gate_ctx && is_app(n)) {
if (e_internalized(n)) {
TRACE("internalize_bug", tout << "forcing enode #" << n->get_id() << " to merge with t/f\n";);
enode * e = get_enode(to_app(n));
set_merge_tf(e, v, false);
}
else {
TRACE("internalize_bug", tout << "creating enode for #" << n->get_id() << "\n";);
mk_enode(to_app(n),
true, /* suppress arguments, we not not use CC for this kind of enode */
true, /* bool enode must be merged with true/false, since it is not in the context of a gate */
false /* CC is not enabled */ );
set_enode_flag(v, false);
if (get_assignment(v) != l_undef)
propagate_bool_var_enode(v);
}
SASSERT(has_enode(v));
}
return;
}
if (m.is_eq(n) && !m.is_iff(n))
internalize_eq(to_app(n), gate_ctx);
else if (m.is_distinct(n))
internalize_distinct(to_app(n), gate_ctx);
else if (is_app(n) && internalize_theory_atom(to_app(n), gate_ctx))
return;
else if (is_quantifier(n))
internalize_quantifier(to_quantifier(n), gate_ctx);
else
internalize_formula_core(to_app(n), gate_ctx);
}
/**
\brief Internalize an equality.
*/
void context::internalize_eq(app * n, bool gate_ctx) {
SASSERT(!b_internalized(n));
SASSERT(m.is_eq(n));
internalize_formula_core(n, gate_ctx);
bool_var v = get_bool_var(n);
bool_var_data & d = get_bdata(v);
d.set_eq_flag();
TRACE("internalize", tout << mk_pp(n, m) << " " << literal(v, false) << "\n";);
sort * s = m.get_sort(n->get_arg(0));
theory * th = m_theories.get_plugin(s->get_family_id());
if (th)
th->internalize_eq_eh(n, v);
}
/**
\brief Internalize distinct constructor.
*/
void context::internalize_distinct(app * n, bool gate_ctx) {
TRACE("distinct", tout << "internalizing distinct: " << mk_pp(n, m) << "\n";);
SASSERT(!b_internalized(n));
SASSERT(m.is_distinct(n));
bool_var v = mk_bool_var(n);
literal l(v);
expr_ref def(m.mk_distinct_expanded(n->get_num_args(), n->get_args()), m);
internalize_rec(def, true);
literal l_def = get_literal(def);
mk_gate_clause(~l, l_def);
mk_gate_clause(l, ~l_def);
// when n->get_num_args() == 2, then mk_distinct_expanded produces a negation.
// reference counts of negations are not tracked so add relevance dependency
// of the equality.
if (m.is_not(def)) def = to_app(def)->get_arg(0);
add_relevancy_dependency(n, def);
if (!gate_ctx) {
mk_enode(n, true, true, false);
set_enode_flag(v, true);
SASSERT(get_assignment(v) == l_undef || get_assignment(l_def) != l_undef);
}
}
/**
\brief Try to internalize n as a theory atom. Return true if succeeded.
The application can be internalize as a theory atom, if there is a theory (plugin)
that can internalize n.
*/
bool context::internalize_theory_atom(app * n, bool gate_ctx) {
SASSERT(!b_internalized(n));
theory * th = m_theories.get_plugin(n->get_family_id());
TRACE("datatype_bug", tout << "internalizing theory atom:\n" << mk_pp(n, m) << "\n";);
if (!th || !th->internalize_atom(n, gate_ctx))
return false;
TRACE("datatype_bug", tout << "internalization succeeded\n" << mk_pp(n, m) << "\n";);
SASSERT(b_internalized(n));
TRACE("internalize_theory_atom", tout << "internalizing theory atom: #" << n->get_id() << "\n";);
bool_var v = get_bool_var(n);
if (!gate_ctx) {
// if the formula is not in the context of a gate, then it
// must be associated with an enode.
if (!e_internalized(n)) {
mk_enode(to_app(n),
true, /* suppress arguments, we not not use CC for this kind of enode */
true /* bool enode must be merged with true/false, since it is not in the context of a gate */,
false /* CC is not enabled */);
}
else {
SASSERT(e_internalized(n));
enode * e = get_enode(n);
set_enode_flag(v, true);
set_merge_tf(e, v, true);
}
}
if (e_internalized(n)) {
set_enode_flag(v, true);
if (get_assignment(v) != l_undef)
propagate_bool_var_enode(v);
}
SASSERT(!e_internalized(n) || has_enode(v));
return true;
}
#ifdef Z3DEBUG
struct check_pattern_proc {
void operator()(var * v) {}
void operator()(quantifier * q) {}
void operator()(app * n) {
if (is_ground(n))
return;
SASSERT(n->get_decl()->is_flat_associative() || n->get_num_args() == n->get_decl()->get_arity());
}
};
/**
Debugging code: check whether for all (non-ground) applications (f a_1 ... a_n) in t, f->get_arity() == n
*/
static bool check_pattern(expr * t) {
check_pattern_proc p;
for_each_expr(p, t);
return true;
}
static bool check_patterns(quantifier * q) {
for (unsigned i = 0; i < q->get_num_patterns(); i++) {
SASSERT(check_pattern(q->get_pattern(i)));
}
for (unsigned i = 0; i < q->get_num_no_patterns(); i++) {
SASSERT(check_pattern(q->get_no_pattern(i)));
}
return true;
}
#endif
/**
\brief Internalize the given quantifier into the logical
context.
*/
void context::internalize_quantifier(quantifier * q, bool gate_ctx) {
TRACE("internalize_quantifier", tout << mk_pp(q, m) << "\n";);
CTRACE("internalize_quantifier_zero", q->get_weight() == 0, tout << mk_pp(q, m) << "\n";);
SASSERT(gate_ctx); // limitation of the current implementation
SASSERT(!b_internalized(q));
if (!is_forall(q))
throw default_exception("internalization of exists is not supported");
SASSERT(is_forall(q));
SASSERT(check_patterns(q));
bool_var v = mk_bool_var(q);
unsigned generation = m_generation;
unsigned _generation;
if (!m_cached_generation.empty() && m_cached_generation.find(q, _generation)) {
generation = _generation;
}
// TODO: do we really need this flag?
bool_var_data & d = get_bdata(v);
d.set_quantifier_flag();
m_qmanager->add(q, generation);
}
void context::internalize_lambda(quantifier * q) {
TRACE("internalize_quantifier", tout << mk_pp(q, m) << "\n";);
SASSERT(is_lambda(q));
if (e_internalized(q)) {
return;
}
app_ref lam_name(m.mk_fresh_const("lambda", m.get_sort(q)), m);
app_ref eq(m), lam_app(m);
expr_ref_vector vars(m);
vars.push_back(lam_name);
unsigned sz = q->get_num_decls();
for (unsigned i = 0; i < sz; ++i) {
vars.push_back(m.mk_var(sz - i - 1, q->get_decl_sort(i)));
}
array_util autil(m);
lam_app = autil.mk_select(vars.size(), vars.c_ptr());
eq = m.mk_eq(lam_app, q->get_expr());
quantifier_ref fa(m);
expr * patterns[1] = { m.mk_pattern(lam_app) };
fa = m.mk_forall(sz, q->get_decl_sorts(), q->get_decl_names(), eq, 0, m.lambda_def_qid(), symbol::null, 1, patterns);
internalize_quantifier(fa, true);
if (!e_internalized(lam_name)) internalize_uninterpreted(lam_name);
m_app2enode.setx(q->get_id(), get_enode(lam_name), nullptr);
m_l_internalized_stack.push_back(q);
m_trail_stack.push_back(&m_mk_lambda_trail);
}
/**
\brief Internalize gates and (uninterpreted and equality) predicates.
*/
void context::internalize_formula_core(app * n, bool gate_ctx) {
SASSERT(!b_internalized(n));
SASSERT(!e_internalized(n));
CTRACE("resolve_conflict_crash", m.is_not(n), tout << mk_ismt2_pp(n, m) << "\ngate_ctx: " << gate_ctx << "\n";);
bool _is_gate = is_gate(m, n) || m.is_not(n);
// process args
for (expr * arg : *n) {
internalize_rec(arg, _is_gate);
}
CTRACE("internalize_bug", b_internalized(n), tout << mk_ll_pp(n, m) << "\n";);
bool is_new_var = false;
bool_var v;
// n can be already internalized after its children are internalized.
// Example (ite-term): (= (ite c 1 0) 1)
//
// When (ite c 1 0) is internalized, it will force the internalization of (= (ite c 1 0) 1) and (= (ite c 1 0) 0)
//
// TODO: avoid the problem by delaying the internalization of (= (ite c 1 0) 1) and (= (ite c 1 0) 0).
// Add them to a queue.
if (!b_internalized(n)) {
is_new_var = true;
v = mk_bool_var(n);
}
else {
v = get_bool_var(n);
}
// a formula needs to be associated with an enode when:
// 1) it is not in the context of a gate, or
// 2) it has arguments and it is not a gate (i.e., uninterpreted predicate or equality).
if (!e_internalized(n) && (!gate_ctx || (!_is_gate && n->get_num_args() > 0))) {
bool suppress_args = _is_gate || m.is_not(n);
bool merge_tf = !gate_ctx;
mk_enode(n, suppress_args, merge_tf, true);
set_enode_flag(v, is_new_var);
SASSERT(has_enode(v));
}
// The constraints associated with node 'n' should be asserted
// after the bool_var and enode associated with are created.
// Reason: incompleteness. An assigned boolean variable is only inserted
// in m_atom_propagation_queue if the predicate is_atom() is true.
// When the constraints for n are created, they may force v to be assigned.
// Now, if v is assigned before being associated with an enode, then
// v is not going to be inserted in m_atom_propagation_queue, and
// propagate_bool_var_enode() method is not going to be invoked for v.
if (is_new_var && n->get_family_id() == m.get_basic_family_id()) {
switch (n->get_decl_kind()) {
case OP_NOT:
SASSERT(!gate_ctx);
mk_not_cnstr(to_app(n));
break;
case OP_AND:
mk_and_cnstr(to_app(n));
add_and_rel_watches(to_app(n));
break;
case OP_OR:
mk_or_cnstr(to_app(n));
add_or_rel_watches(to_app(n));
break;
case OP_EQ:
if (m.is_iff(n))
mk_iff_cnstr(to_app(n), false);
break;
case OP_ITE:
mk_ite_cnstr(to_app(n));
add_ite_rel_watches(to_app(n));
break;
case OP_TRUE:
case OP_FALSE:
break;
case OP_XOR:
mk_iff_cnstr(to_app(n), true);
break;
case OP_DISTINCT:
case OP_IMPLIES:
throw default_exception("formula has not been simplified");
case OP_OEQ:
UNREACHABLE();
default:
break;
}
}
CTRACE("internalize_bug", e_internalized(n),
tout << "#" << n->get_id() << ", merge_tf: " << get_enode(n)->merge_tf() << "\n";);
}
/**
\brief Trail object to disable the m_merge_tf flag of an enode.
*/
class set_merge_tf_trail : public trail<context> {
enode * m_node;
public:
set_merge_tf_trail(enode * n):
m_node(n) {
}
void undo(context & ctx) override {
m_node->m_merge_tf = false;
}
};
/**
\brief Enable the flag m_merge_tf in the given enode. When the
flag m_merge_tf is enabled, the enode n will be merged with the
true_enode (false_enode) whenever the Boolean variable v is
assigned to true (false).
If is_new_var is true, then trail is not created for the flag update.
*/
void context::set_merge_tf(enode * n, bool_var v, bool is_new_var) {
SASSERT(bool_var2enode(v) == n);
if (!n->m_merge_tf) {
if (!is_new_var)
push_trail(set_merge_tf_trail(n));
n->m_merge_tf = true;
lbool val = get_assignment(v);
switch (val) {
case l_undef:
break;
case l_true:
if (n->get_root() != m_true_enode->get_root())
push_eq(n, m_true_enode, eq_justification(literal(v, false)));
break;
case l_false:
if (n->get_root() != m_false_enode->get_root())
push_eq(n, m_false_enode, eq_justification(literal(v, true)));
break;
}
}
}
/**
\brief Trail object to disable the m_enode flag of a Boolean
variable. The flag m_enode is true for a Boolean variable v,
if there is an enode n associated with it.
*/
class set_enode_flag_trail : public trail<context> {
bool_var m_var;
public:
set_enode_flag_trail(bool_var v):
m_var(v) {
}
void undo(context & ctx) override {
bool_var_data & data = ctx.m_bdata[m_var];
data.reset_enode_flag();
}
};
/**
\brief Enable the flag m_enode in the given boolean variable. That is,
the boolean variable is associated with an enode.
If is_new_var is true, then trail is not created for the flag uodate.
*/
void context::set_enode_flag(bool_var v, bool is_new_var) {
SASSERT(e_internalized(bool_var2expr(v)));
bool_var_data & data = m_bdata[v];
if (!data.is_enode()) {
if (!is_new_var)
push_trail(set_enode_flag_trail(v));
data.set_enode_flag();
}
}
/**
\brief Internalize the given term into the logical context.
*/
void context::internalize_term(app * n) {
if (e_internalized(n)) {
theory * th = m_theories.get_plugin(n->get_family_id());
if (th != nullptr) {
// This code is necessary because some theories may decide
// not to create theory variables for a nested application.
// Example:
// Suppose (+ (* 2 x) y) is internalized by arithmetic
// and an enode is created for the + and * applications,
// but a theory variable is only created for the + application.
// The (* 2 x) is internal to the arithmetic module.
// Later, the core tries to internalize (f (* 2 x)).
// Now, (* 2 x) is not internal to arithmetic anymore,
// and a theory variable must be created for it.
enode * e = get_enode(n);
if (!th->is_attached_to_var(e))
internalize_theory_term(n);
}
return;
}
if (m.is_term_ite(n)) {
internalize_ite_term(n);
return; // it is not necessary to apply sort constraint
}
else if (internalize_theory_term(n)) {
// skip
}
else {
internalize_uninterpreted(n);
}
SASSERT(e_internalized(n));
enode * e = get_enode(n);
apply_sort_cnstr(n, e);
}
/**
\brief Internalize an if-then-else term.
*/
void context::internalize_ite_term(app * n) {
SASSERT(!e_internalized(n));
expr * c = n->get_arg(0);
expr * t = n->get_arg(1);
expr * e = n->get_arg(2);
app_ref eq1(mk_eq_atom(n, t), m);
app_ref eq2(mk_eq_atom(n, e), m);
mk_enode(n,
true /* suppress arguments, I don't want to apply CC on ite terms */,
false /* it is a term, so it should not be merged with true/false */,
false /* CC is not enabled */);
internalize_rec(c, true);
internalize_rec(t, false);
internalize_rec(e, false);
internalize_rec(eq1, true);
internalize_rec(eq2, true);
literal c_lit = get_literal(c);
literal eq1_lit = get_literal(eq1);
literal eq2_lit = get_literal(eq2);
TRACE("internalize_ite_term_bug",
tout << mk_ismt2_pp(n, m) << "\n";
tout << mk_ismt2_pp(c, m) << "\n";
tout << mk_ismt2_pp(t, m) << "\n";
tout << mk_ismt2_pp(e, m) << "\n";
tout << mk_ismt2_pp(eq1, m) << "\n";
tout << mk_ismt2_pp(eq2, m) << "\n";
tout << "literals:\n" << c_lit << " " << eq1_lit << " " << eq2_lit << "\n";);
mk_gate_clause(~c_lit, eq1_lit);
mk_gate_clause( c_lit, eq2_lit);
if (relevancy()) {
relevancy_eh * eh = m_relevancy_propagator->mk_term_ite_relevancy_eh(n, eq1, eq2);
TRACE("ite_term_relevancy", tout << "#" << n->get_id() << " #" << eq1->get_id() << " #" << eq2->get_id() << "\n";);
add_rel_watch(c_lit, eh);
add_rel_watch(~c_lit, eh);
add_relevancy_eh(n, eh);
}
SASSERT(e_internalized(n));
}
/**
\brief Try to internalize a theory term. That is, a theory (plugin)
will be invoked to internalize n. Return true if succeeded.
It may fail because there is no plugin or the plugin does not support it.
*/
bool context::internalize_theory_term(app * n) {
theory * th = m_theories.get_plugin(n->get_family_id());
if (!th || !th->internalize_term(n))
return false;
return true;
}
/**
\brief Internalize an uninterpreted function application or constant.
*/
void context::internalize_uninterpreted(app * n) {
SASSERT(!e_internalized(n));
// process args
for (expr * arg : *n) {
internalize_rec(arg, false);
SASSERT(e_internalized(arg));
}
enode * e = mk_enode(n,
false, /* do not suppress args */
false, /* it is a term, so it should not be merged with true/false */
true);
apply_sort_cnstr(n, e);
}
/**
\brief Create a new boolean variable and associate it with n.
*/
bool_var context::mk_bool_var(expr * n) {
SASSERT(!b_internalized(n));
//SASSERT(!m.is_not(n));
unsigned id = n->get_id();
bool_var v = m_b_internalized_stack.size();
TRACE("mk_bool_var", tout << "creating boolean variable: " << v << " for:\n" << mk_pp(n, m) << " " << n->get_id() << "\n";);
TRACE("mk_var_bug", tout << "mk_bool: " << v << "\n";);
set_bool_var(id, v);
m_bdata.reserve(v+1);
m_activity.reserve(v+1);
m_bool_var2expr.reserve(v+1);
m_bool_var2expr[v] = n;
literal l(v, false);
literal not_l(v, true);
unsigned aux = std::max(l.index(), not_l.index()) + 1;
m_assignment.reserve(aux);
m_assignment[l.index()] = l_undef;
m_assignment[not_l.index()] = l_undef;
m_watches.reserve(aux);
SASSERT(m_assignment.size() == m_watches.size());
m_watches[l.index()] .reset();
m_watches[not_l.index()] .reset();
m_lit_occs.reserve(aux, 0);
m_lit_occs[l.index()] = 0;
m_lit_occs[not_l.index()] = 0;
bool_var_data & data = m_bdata[v];
unsigned iscope_lvl = m_scope_lvl; // record when the boolean variable was internalized.
data.init(iscope_lvl);
if (m_fparams.m_random_initial_activity == IA_RANDOM || (m_fparams.m_random_initial_activity == IA_RANDOM_WHEN_SEARCHING && m_searching))
m_activity[v] = -((m_random() % 1000) / 1000.0);
else
m_activity[v] = 0.0;
m_case_split_queue->mk_var_eh(v);
m_b_internalized_stack.push_back(n);
m_trail_stack.push_back(&m_mk_bool_var_trail);
m_stats.m_num_mk_bool_var++;
SASSERT(check_bool_var_vector_sizes());
return v;
}
void context::undo_mk_bool_var() {
SASSERT(!m_b_internalized_stack.empty());
m_stats.m_num_del_bool_var++;
expr * n = m_b_internalized_stack.back();
unsigned n_id = n->get_id();
bool_var v = get_bool_var_of_id(n_id);
m_bool_var2expr[v] = nullptr;
TRACE("undo_mk_bool_var", tout << "undo_bool: " << v << "\n" << mk_pp(n, m) << "\n" << "m_bdata.size: " << m_bdata.size()
<< " m_assignment.size: " << m_assignment.size() << "\n";);
TRACE("mk_var_bug", tout << "undo_mk_bool: " << v << "\n";);
// bool_var_data & d = m_bdata[v];
m_case_split_queue->del_var_eh(v);
if (is_quantifier(n))
m_qmanager->del(to_quantifier(n));
set_bool_var(n_id, null_bool_var);
m_b_internalized_stack.pop_back();
}
/**
\brief Create an new enode.
\remark If suppress_args is true, then the enode is viewed as a constant
in the egraph.
*/
enode * context::mk_enode(app * n, bool suppress_args, bool merge_tf, bool cgc_enabled) {
TRACE("mk_enode_detail", tout << mk_pp(n, m) << "\nsuppress_args: " << suppress_args << ", merge_tf: " <<
merge_tf << ", cgc_enabled: " << cgc_enabled << "\n";);
SASSERT(!e_internalized(n));
unsigned id = n->get_id();
unsigned generation = m_generation;
unsigned _generation = 0;
if (!m_cached_generation.empty() && m_cached_generation.find(n, _generation)) {
generation = _generation;
CTRACE("cached_generation", generation != m_generation,
tout << "cached_generation: #" << n->get_id() << " " << generation << " " << m_generation << "\n";);
}
enode * e = enode::mk(m, m_region, m_app2enode, n, generation, suppress_args, merge_tf, m_scope_lvl, cgc_enabled, true);
TRACE("mk_enode_detail", tout << "e.get_num_args() = " << e->get_num_args() << "\n";);
if (n->get_num_args() == 0 && m.is_unique_value(n))
e->mark_as_interpreted();
TRACE("mk_var_bug", tout << "mk_enode: " << id << "\n";);
TRACE("generation", tout << "mk_enode: " << id << " " << generation << "\n";);
m_app2enode.setx(id, e, nullptr);
m_e_internalized_stack.push_back(n);
m_trail_stack.push_back(&m_mk_enode_trail);
m_enodes.push_back(e);
if (e->get_num_args() > 0) {
if (e->is_true_eq()) {
bool_var v = enode2bool_var(e);
assign(literal(v), mk_justification(eq_propagation_justification(e->get_arg(0), e->get_arg(1))));
e->m_cg = e;
}
else {
if (cgc_enabled) {
enode_bool_pair pair = m_cg_table.insert(e);
enode * e_prime = pair.first;
if (e != e_prime) {
e->m_cg = e_prime;
bool used_commutativity = pair.second;
push_new_congruence(e, e_prime, used_commutativity);
}
else {
e->m_cg = e;
}
}
else {
e->m_cg = e;