-
Notifications
You must be signed in to change notification settings - Fork 273
/
Copy pathsmt2_conv.cpp
5953 lines (5304 loc) · 160 KB
/
smt2_conv.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
/*******************************************************************\
Module: SMT Backend
Author: Daniel Kroening, [email protected]
\*******************************************************************/
/// \file
/// SMT Backend
#include "smt2_conv.h"
#include <util/arith_tools.h>
#include <util/bitvector_expr.h>
#include <util/byte_operators.h>
#include <util/c_types.h>
#include <util/config.h>
#include <util/expr_iterator.h>
#include <util/expr_util.h>
#include <util/fixedbv.h>
#include <util/floatbv_expr.h>
#include <util/format_expr.h>
#include <util/ieee_float.h>
#include <util/invariant.h>
#include <util/mathematical_expr.h>
#include <util/namespace.h>
#include <util/pointer_offset_size.h>
#include <util/pointer_predicates.h>
#include <util/prefix.h>
#include <util/range.h>
#include <util/simplify_expr.h>
#include <util/std_expr.h>
#include <util/string2int.h>
#include <util/string_constant.h>
#include <util/threeval.h>
#include <solvers/flattening/boolbv_width.h>
#include <solvers/flattening/c_bit_field_replacement_type.h>
#include <solvers/floatbv/float_bv.h>
#include <solvers/prop/literal_expr.h>
#include "smt2_tokenizer.h"
#include <cstdint>
// Mark different kinds of error conditions
// Unexpected types and other combinations not implemented and not
// expected to be needed
#define UNEXPECTEDCASE(S) PRECONDITION_WITH_DIAGNOSTICS(false, S);
// General todos
#define SMT2_TODO(S) PRECONDITION_WITH_DIAGNOSTICS(false, "TODO: " S)
smt2_convt::smt2_convt(
const namespacet &_ns,
const std::string &_benchmark,
const std::string &_notes,
const std::string &_logic,
solvert _solver,
std::ostream &_out)
: use_FPA_theory(false),
use_array_of_bool(false),
use_as_const(false),
use_check_sat_assuming(false),
use_datatypes(false),
use_lambda_for_array(false),
emit_set_logic(true),
ns(_ns),
out(_out),
benchmark(_benchmark),
notes(_notes),
logic(_logic),
solver(_solver),
boolbv_width(_ns),
pointer_logic(_ns),
no_boolean_variables(0)
{
// We set some defaults differently
// for some solvers.
switch(solver)
{
case solvert::GENERIC:
break;
case solvert::BITWUZLA:
use_FPA_theory = true;
use_array_of_bool = true;
use_as_const = true;
use_check_sat_assuming = true;
use_lambda_for_array = false;
emit_set_logic = false;
break;
case solvert::BOOLECTOR:
break;
case solvert::CPROVER_SMT2:
use_FPA_theory = true;
use_array_of_bool = true;
use_as_const = true;
use_check_sat_assuming = true;
emit_set_logic = false;
break;
case solvert::CVC3:
break;
case solvert::CVC4:
logic = "ALL";
use_array_of_bool = true;
use_as_const = true;
break;
case solvert::CVC5:
logic = "ALL";
use_FPA_theory = true;
use_array_of_bool = true;
use_as_const = true;
use_check_sat_assuming = true;
use_datatypes = true;
break;
case solvert::MATHSAT:
break;
case solvert::YICES:
break;
case solvert::Z3:
use_array_of_bool = true;
use_as_const = true;
use_check_sat_assuming = true;
use_lambda_for_array = true;
emit_set_logic = false;
use_datatypes = true;
break;
}
write_header();
}
std::string smt2_convt::decision_procedure_text() const
{
return "SMT2";
}
void smt2_convt::print_assignment(std::ostream &os) const
{
// Boolean stuff
for(std::size_t v=0; v<boolean_assignment.size(); v++)
os << "b" << v << "=" << boolean_assignment[v] << "\n";
// others
}
tvt smt2_convt::l_get(literalt l) const
{
if(l.is_true())
return tvt(true);
if(l.is_false())
return tvt(false);
INVARIANT(
l.var_no() < boolean_assignment.size(),
"variable number shall be within bounds");
return tvt(boolean_assignment[l.var_no()]^l.sign());
}
void smt2_convt::write_header()
{
out << "; SMT 2" << "\n";
switch(solver)
{
// clang-format off
case solvert::GENERIC: break;
case solvert::BITWUZLA: out << "; Generated for Bitwuzla\n"; break;
case solvert::BOOLECTOR: out << "; Generated for Boolector\n"; break;
case solvert::CPROVER_SMT2:
out << "; Generated for the CPROVER SMT2 solver\n"; break;
case solvert::CVC3: out << "; Generated for CVC 3\n"; break;
case solvert::CVC4: out << "; Generated for CVC 4\n"; break;
case solvert::CVC5: out << "; Generated for CVC 5\n"; break;
case solvert::MATHSAT: out << "; Generated for MathSAT\n"; break;
case solvert::YICES: out << "; Generated for Yices\n"; break;
case solvert::Z3: out << "; Generated for Z3\n"; break;
// clang-format on
}
out << "(set-info :source \"" << notes << "\")" << "\n";
out << "(set-option :produce-models true)" << "\n";
// We use a broad mixture of logics, so on some solvers
// its better not to declare here.
// set-logic should come after setting options
if(emit_set_logic && !logic.empty())
out << "(set-logic " << logic << ")" << "\n";
}
void smt2_convt::write_footer()
{
out << "\n";
// fix up the object sizes
for(const auto &object : object_sizes)
define_object_size(object.second, object.first);
if(use_check_sat_assuming && !assumptions.empty())
{
out << "(check-sat-assuming (";
for(const auto &assumption : assumptions)
convert_literal(assumption);
out << "))\n";
}
else
{
// add the assumptions, if any
if(!assumptions.empty())
{
out << "; assumptions\n";
for(const auto &assumption : assumptions)
{
out << "(assert ";
convert_literal(assumption);
out << ")"
<< "\n";
}
}
out << "(check-sat)\n";
}
out << "\n";
if(solver!=solvert::BOOLECTOR)
{
for(const auto &id : smt2_identifiers)
out << "(get-value (" << id << "))"
<< "\n";
}
out << "\n";
out << "(exit)\n";
out << "; end of SMT2 file"
<< "\n";
}
/// Returns true iff \p type has effective width of zero bits.
static bool is_zero_width(const typet &type, const namespacet &ns)
{
if(type.id() == ID_empty)
return true;
else if(type.id() == ID_struct_tag)
return is_zero_width(ns.follow_tag(to_struct_tag_type(type)), ns);
else if(type.id() == ID_union_tag)
return is_zero_width(ns.follow_tag(to_union_tag_type(type)), ns);
else if(type.id() == ID_struct || type.id() == ID_union)
{
for(const auto &comp : to_struct_union_type(type).components())
{
if(!is_zero_width(comp.type(), ns))
return false;
}
return true;
}
else if(auto array_type = type_try_dynamic_cast<array_typet>(type))
{
// we ignore array_type->size().is_zero() for now as there may be
// out-of-bounds accesses that we need to model
return is_zero_width(array_type->element_type(), ns);
}
else
return false;
}
void smt2_convt::define_object_size(
const irep_idt &id,
const object_size_exprt &expr)
{
const exprt &ptr = expr.pointer();
std::size_t pointer_width = boolbv_width(ptr.type());
std::size_t number = 0;
std::size_t h=pointer_width-1;
std::size_t l=pointer_width-config.bv_encoding.object_bits;
for(const auto &o : pointer_logic.objects)
{
const typet &type = o.type();
auto size_expr = size_of_expr(type, ns);
if(
(o.id() != ID_symbol && o.id() != ID_string_constant) ||
!size_expr.has_value())
{
++number;
continue;
}
find_symbols(*size_expr);
out << "(assert (=> (= "
<< "((_ extract " << h << " " << l << ") ";
convert_expr(ptr);
out << ") (_ bv" << number << " " << config.bv_encoding.object_bits << "))"
<< "(= " << id << " ";
convert_expr(*size_expr);
out << ")))\n";
++number;
}
}
decision_proceduret::resultt smt2_convt::dec_solve(const exprt &assumption)
{
if(assumption.is_nil())
write_footer();
else
{
assumptions.push_back(convert(assumption));
write_footer();
assumptions.pop_back();
}
out.flush();
return decision_proceduret::resultt::D_ERROR;
}
exprt smt2_convt::get(const exprt &expr) const
{
if(expr.id()==ID_symbol)
{
const irep_idt &id=to_symbol_expr(expr).get_identifier();
identifier_mapt::const_iterator it=identifier_map.find(id);
if(it!=identifier_map.end())
return it->second.value;
return expr;
}
else if(expr.id()==ID_nondet_symbol)
{
const irep_idt &id=to_nondet_symbol_expr(expr).get_identifier();
identifier_mapt::const_iterator it=identifier_map.find(id);
if(it!=identifier_map.end())
return it->second.value;
}
else if(expr.id() == ID_literal)
{
auto l = to_literal_expr(expr).get_literal();
if(l_get(l).is_true())
return true_exprt();
else
return false_exprt();
}
else if(expr.id() == ID_not)
{
auto op = get(to_not_expr(expr).op());
if(op.is_true())
return false_exprt();
else if(op.is_false())
return true_exprt();
}
else if(
expr.is_constant() || expr.id() == ID_empty_union ||
(!expr.has_operands() && (expr.id() == ID_struct || expr.id() == ID_array)))
{
return expr;
}
else if(expr.has_operands())
{
exprt copy = expr;
for(auto &op : copy.operands())
{
exprt eval_op = get(op);
if(eval_op.is_nil())
return nil_exprt{};
op = std::move(eval_op);
}
return copy;
}
return nil_exprt();
}
constant_exprt smt2_convt::parse_literal(
const irept &src,
const typet &type)
{
// See http://www.grammatech.com/resources/smt/SMTLIBTutorial.pdf for the
// syntax of SMTlib2 literals.
//
// A literal expression is one of the following forms:
//
// * Numeral -- this is a natural number in decimal and is of the form:
// 0|([1-9][0-9]*)
// * Decimal -- this is a decimal expansion of a real number of the form:
// (0|[1-9][0-9]*)[.]([0-9]+)
// * Binary -- this is a natural number in binary and is of the form:
// #b[01]+
// * Hex -- this is a natural number in hexadecimal and is of the form:
// #x[0-9a-fA-F]+
//
// Right now I'm not parsing decimals. It'd be nice if we had a real YACC
// parser here, but whatever.
mp_integer value;
if(!src.id().empty())
{
const std::string &s=src.id_string();
if(s.size()>=2 && s[0]=='#' && s[1]=='b')
{
// Binary #b010101
value=string2integer(s.substr(2), 2);
}
else if(s.size()>=2 && s[0]=='#' && s[1]=='x')
{
// Hex #x012345
value=string2integer(s.substr(2), 16);
}
else
{
// Numeral
value=string2integer(s);
}
}
else if(src.get_sub().size()==2 &&
src.get_sub()[0].id()=="-") // (- 100)
{
value=-string2integer(src.get_sub()[1].id_string());
}
else if(src.get_sub().size()==3 &&
src.get_sub()[0].id()=="_" &&
// (_ bvDECIMAL_VALUE SIZE)
src.get_sub()[1].id_string().substr(0, 2)=="bv")
{
value=string2integer(src.get_sub()[1].id_string().substr(2));
}
else if(src.get_sub().size()==4 &&
src.get_sub()[0].id()=="fp") // (fp signbv exponentbv significandbv)
{
if(type.id()==ID_floatbv)
{
const floatbv_typet &floatbv_type=to_floatbv_type(type);
constant_exprt s1 = parse_literal(src.get_sub()[1], unsignedbv_typet(1));
constant_exprt s2 =
parse_literal(src.get_sub()[2], unsignedbv_typet(floatbv_type.get_e()));
constant_exprt s3 =
parse_literal(src.get_sub()[3], unsignedbv_typet(floatbv_type.get_f()));
const auto s1_int = numeric_cast_v<mp_integer>(s1);
const auto s2_int = numeric_cast_v<mp_integer>(s2);
const auto s3_int = numeric_cast_v<mp_integer>(s3);
// stitch the bits together
value = bitwise_or(
s1_int << (floatbv_type.get_e() + floatbv_type.get_f()),
bitwise_or((s2_int << floatbv_type.get_f()), s3_int));
}
else
value=0;
}
else if(src.get_sub().size()==4 &&
src.get_sub()[0].id()=="_" &&
src.get_sub()[1].id()=="+oo") // (_ +oo e s)
{
std::size_t e = unsafe_string2size_t(src.get_sub()[2].id_string());
std::size_t s = unsafe_string2size_t(src.get_sub()[3].id_string());
return ieee_float_valuet::plus_infinity(ieee_float_spect(s - 1, e))
.to_expr();
}
else if(src.get_sub().size()==4 &&
src.get_sub()[0].id()=="_" &&
src.get_sub()[1].id()=="-oo") // (_ -oo e s)
{
std::size_t e = unsafe_string2size_t(src.get_sub()[2].id_string());
std::size_t s = unsafe_string2size_t(src.get_sub()[3].id_string());
return ieee_float_valuet::minus_infinity(ieee_float_spect(s - 1, e))
.to_expr();
}
else if(src.get_sub().size()==4 &&
src.get_sub()[0].id()=="_" &&
src.get_sub()[1].id()=="NaN") // (_ NaN e s)
{
std::size_t e = unsafe_string2size_t(src.get_sub()[2].id_string());
std::size_t s = unsafe_string2size_t(src.get_sub()[3].id_string());
return ieee_float_valuet::NaN(ieee_float_spect(s - 1, e)).to_expr();
}
if(type.id()==ID_signedbv ||
type.id()==ID_unsignedbv ||
type.id()==ID_c_enum ||
type.id()==ID_c_bool)
{
return from_integer(value, type);
}
else if(type.id()==ID_c_enum_tag)
{
constant_exprt result =
from_integer(value, ns.follow_tag(to_c_enum_tag_type(type)));
// restore the c_enum_tag type
result.type() = type;
return result;
}
else if(type.id()==ID_fixedbv ||
type.id()==ID_floatbv)
{
std::size_t width=boolbv_width(type);
return constant_exprt(integer2bvrep(value, width), type);
}
else if(type.id()==ID_integer ||
type.id()==ID_range)
{
return from_integer(value, type);
}
else
UNREACHABLE_BECAUSE(
"smt2_convt::parse_literal should not be of unsupported type " +
type.id_string());
}
exprt smt2_convt::parse_array(
const irept &src,
const array_typet &type)
{
std::unordered_map<int64_t, exprt> operands_map;
walk_array_tree(&operands_map, src, type);
exprt::operandst operands;
// Try to find the default value, if there is none then set it
auto maybe_default_op = operands_map.find(-1);
exprt default_op;
if(maybe_default_op == operands_map.end())
default_op = nil_exprt();
else
default_op = maybe_default_op->second;
int64_t i = 0;
auto maybe_size = numeric_cast<std::int64_t>(type.size());
if(maybe_size.has_value())
{
while(i < maybe_size.value())
{
auto found_op = operands_map.find(i);
if(found_op != operands_map.end())
operands.emplace_back(found_op->second);
else
operands.emplace_back(default_op);
i++;
}
}
else
{
// Array size is unknown, keep adding with known indexes in order
// until we fail to find one.
auto found_op = operands_map.find(i);
while(found_op != operands_map.end())
{
operands.emplace_back(found_op->second);
i++;
found_op = operands_map.find(i);
}
operands.emplace_back(default_op);
}
return array_exprt(operands, type);
}
void smt2_convt::walk_array_tree(
std::unordered_map<int64_t, exprt> *operands_map,
const irept &src,
const array_typet &type)
{
if(src.get_sub().size()==4 && src.get_sub()[0].id()=="store")
{
// This is the SMT syntax being parsed here
// (store array index value)
// Recurse
walk_array_tree(operands_map, src.get_sub()[1], type);
const auto index_expr = parse_rec(src.get_sub()[2], type.size().type());
const constant_exprt index_constant = to_constant_expr(index_expr);
mp_integer tempint;
bool failure = to_integer(index_constant, tempint);
if(failure)
return;
long index = tempint.to_long();
exprt value = parse_rec(src.get_sub()[3], type.element_type());
operands_map->emplace(index, value);
}
else if(src.get_sub().size()==2 &&
src.get_sub()[0].get_sub().size()==3 &&
src.get_sub()[0].get_sub()[0].id()=="as" &&
src.get_sub()[0].get_sub()[1].id()=="const")
{
// (as const type_info default_value)
exprt default_value = parse_rec(src.get_sub()[1], type.element_type());
operands_map->emplace(-1, default_value);
}
else
{
auto bindings_it = current_bindings.find(src.id());
if(bindings_it != current_bindings.end())
walk_array_tree(operands_map, bindings_it->second, type);
}
}
exprt smt2_convt::parse_union(
const irept &src,
const union_typet &type)
{
// these are always flat
PRECONDITION(!type.components().empty());
const union_typet::componentt &first=type.components().front();
std::size_t width=boolbv_width(type);
exprt value = parse_rec(src, unsignedbv_typet(width));
if(value.is_nil())
return nil_exprt();
const typecast_exprt converted(value, first.type());
return union_exprt(first.get_name(), converted, type);
}
struct_exprt
smt2_convt::parse_struct(const irept &src, const struct_typet &type)
{
const struct_typet::componentst &components =
type.components();
struct_exprt result(exprt::operandst(components.size(), nil_exprt()), type);
if(components.empty())
return result;
if(use_datatypes)
{
// Structs look like:
// (mk-struct.1 <component0> <component1> ... <componentN>)
std::size_t j = 1;
for(std::size_t i=0; i<components.size(); i++)
{
const struct_typet::componentt &c=components[i];
if(is_zero_width(components[i].type(), ns))
{
result.operands()[i] = nil_exprt{};
}
else
{
DATA_INVARIANT(
src.get_sub().size() > j, "insufficient number of component values");
result.operands()[i] = parse_rec(src.get_sub()[j], c.type());
++j;
}
}
}
else
{
// These are just flattened, i.e., we expect to see a monster bit vector.
std::size_t total_width=boolbv_width(type);
const auto l = parse_literal(src, unsignedbv_typet(total_width));
const irep_idt binary =
integer2binary(numeric_cast_v<mp_integer>(l), total_width);
CHECK_RETURN(binary.size() == total_width);
std::size_t offset=0;
for(std::size_t i=0; i<components.size(); i++)
{
if(is_zero_width(components[i].type(), ns))
continue;
std::size_t component_width=boolbv_width(components[i].type());
INVARIANT(
offset + component_width <= total_width,
"struct component bits shall be within struct bit vector");
std::string component_binary=
"#b"+id2string(binary).substr(
total_width-offset-component_width, component_width);
result.operands()[i]=
parse_rec(irept(component_binary), components[i].type());
offset+=component_width;
}
}
return result;
}
exprt smt2_convt::parse_rec(const irept &src, const typet &type)
{
if(src.get_sub().size() == 3 && src.get_sub()[0].id() == ID_let)
{
// This is produced by Z3
// (let (....) (....))
auto previous_bindings = current_bindings;
for(const auto &binding : src.get_sub()[1].get_sub())
{
const irep_idt &name = binding.get_sub()[0].id();
current_bindings.emplace(name, binding.get_sub()[1]);
}
exprt result = parse_rec(src.get_sub()[2], type);
current_bindings = std::move(previous_bindings);
return result;
}
auto bindings_it = current_bindings.find(src.id());
if(bindings_it != current_bindings.end())
{
return parse_rec(bindings_it->second, type);
}
if(
type.id() == ID_signedbv || type.id() == ID_unsignedbv ||
type.id() == ID_integer || type.id() == ID_rational ||
type.id() == ID_real || type.id() == ID_c_enum ||
type.id() == ID_c_enum_tag || type.id() == ID_fixedbv ||
type.id() == ID_floatbv || type.id() == ID_c_bool || type.id() == ID_range)
{
return parse_literal(src, type);
}
else if(type.id()==ID_bool)
{
if(src.id()==ID_1 || src.id()==ID_true)
return true_exprt();
else if(src.id()==ID_0 || src.id()==ID_false)
return false_exprt();
}
else if(type.id()==ID_pointer)
{
// these come in as bit-vector literals
std::size_t width=boolbv_width(type);
constant_exprt bv_expr = parse_literal(src, unsignedbv_typet(width));
mp_integer v = numeric_cast_v<mp_integer>(bv_expr);
// split into object and offset
mp_integer pow=power(2, width-config.bv_encoding.object_bits);
pointer_logict::pointert ptr{numeric_cast_v<std::size_t>(v / pow), v % pow};
return annotated_pointer_constant_exprt(
bv_expr.get_value(),
pointer_logic.pointer_expr(ptr, to_pointer_type(type)));
}
else if(type.id()==ID_struct)
{
return parse_struct(src, to_struct_type(type));
}
else if(type.id() == ID_struct_tag)
{
auto struct_expr =
parse_struct(src, ns.follow_tag(to_struct_tag_type(type)));
// restore the tag type
struct_expr.type() = type;
return std::move(struct_expr);
}
else if(type.id()==ID_union)
{
return parse_union(src, to_union_type(type));
}
else if(type.id() == ID_union_tag)
{
auto union_expr = parse_union(src, ns.follow_tag(to_union_tag_type(type)));
// restore the tag type
union_expr.type() = type;
return union_expr;
}
else if(type.id()==ID_array)
{
return parse_array(src, to_array_type(type));
}
return nil_exprt();
}
void smt2_convt::convert_address_of_rec(
const exprt &expr,
const pointer_typet &result_type)
{
if(
expr.id() == ID_symbol || expr.is_constant() ||
expr.id() == ID_string_constant || expr.id() == ID_label)
{
const std::size_t object_bits = config.bv_encoding.object_bits;
const std::size_t max_objects = std::size_t(1) << object_bits;
const mp_integer object_id = pointer_logic.add_object(expr);
if(object_id >= max_objects)
{
throw analysis_exceptiont{
"too many addressed objects: maximum number of objects is set to 2^n=" +
std::to_string(max_objects) +
" (with n=" + std::to_string(object_bits) + "); " +
"use the `--object-bits n` option to increase the maximum number"};
}
out << "(concat (_ bv" << object_id << " " << object_bits << ")"
<< " (_ bv0 " << boolbv_width(result_type) - object_bits << "))";
}
else if(expr.id()==ID_index)
{
const index_exprt &index_expr = to_index_expr(expr);
const exprt &array = index_expr.array();
const exprt &index = index_expr.index();
if(index.is_zero())
{
if(array.type().id()==ID_pointer)
convert_expr(array);
else if(array.type().id()==ID_array)
convert_address_of_rec(array, result_type);
else
UNREACHABLE;
}
else
{
// this is really pointer arithmetic
index_exprt new_index_expr = index_expr;
new_index_expr.index() = from_integer(0, index.type());
address_of_exprt address_of_expr(
new_index_expr,
pointer_type(to_array_type(array.type()).element_type()));
plus_exprt plus_expr{address_of_expr, index};
convert_expr(plus_expr);
}
}
else if(expr.id()==ID_member)
{
const member_exprt &member_expr=to_member_expr(expr);
const exprt &struct_op=member_expr.struct_op();
const typet &struct_op_type = struct_op.type();
DATA_INVARIANT(
struct_op_type.id() == ID_struct || struct_op_type.id() == ID_struct_tag,
"member expression operand shall have struct type");
const struct_typet &struct_type =
struct_op_type.id() == ID_struct_tag
? ns.follow_tag(to_struct_tag_type(struct_op_type))
: to_struct_type(struct_op_type);
const irep_idt &component_name = member_expr.get_component_name();
const auto offset = member_offset(struct_type, component_name, ns);
CHECK_RETURN(offset.has_value() && *offset >= 0);
unsignedbv_typet index_type(boolbv_width(result_type));
// pointer arithmetic
out << "(bvadd ";
convert_address_of_rec(struct_op, result_type);
convert_expr(from_integer(*offset, index_type));
out << ")"; // bvadd
}
else if(expr.id()==ID_if)
{
const if_exprt &if_expr = to_if_expr(expr);
out << "(ite ";
convert_expr(if_expr.cond());
out << " ";
convert_address_of_rec(if_expr.true_case(), result_type);
out << " ";
convert_address_of_rec(if_expr.false_case(), result_type);
out << ")";
}
else
INVARIANT(
false,
"operand of address of expression should not be of kind " +
expr.id_string());
}
static bool has_quantifier(const exprt &expr)
{
bool result = false;
expr.visit_post([&result](const exprt &node) {
if(node.id() == ID_exists || node.id() == ID_forall)
result = true;
});
return result;
}
literalt smt2_convt::convert(const exprt &expr)
{
PRECONDITION(expr.is_boolean());
// Three cases where no new handle is needed.
if(expr.is_true())
return const_literal(true);
else if(expr.is_false())
return const_literal(false);
else if(expr.id()==ID_literal)
return to_literal_expr(expr).get_literal();
// Need a new handle
out << "\n";
exprt prepared_expr = prepare_for_convert_expr(expr);
literalt l(no_boolean_variables, false);
no_boolean_variables++;
out << "; convert\n";
out << "; Converting var_no " << l.var_no() << " with expr ID of "
<< expr.id_string() << "\n";
// We're converting the expression, so store it in the defined_expressions
// store and in future we use the literal instead of the whole expression
// Note that here we are always converting, so we do not need to consider
// other literal kinds, only "|B###|"
// Z3 refuses get-value when a defined symbol contains a quantifier.
if(has_quantifier(prepared_expr))
{
out << "(declare-fun ";
convert_literal(l);
out << " () Bool)\n";
out << "(assert (= ";
convert_literal(l);
out << ' ';
convert_expr(prepared_expr);
out << "))\n";
}
else
{
auto identifier =
convert_identifier(std::string{"B"} + std::to_string(l.var_no()));
defined_expressions[expr] = identifier;
smt2_identifiers.insert(identifier);
out << "(define-fun " << identifier << " () Bool ";
convert_expr(prepared_expr);
out << ")\n";
}
return l;
}
exprt smt2_convt::handle(const exprt &expr)
{
// We can only improve Booleans.
if(!expr.is_boolean())
return expr;
return literal_exprt(convert(expr));
}
void smt2_convt::convert_literal(const literalt l)
{
if(l==const_literal(false))
out << "false";
else if(l==const_literal(true))
out << "true";
else
{
if(l.sign())
out << "(not ";
const auto identifier =
convert_identifier("B" + std::to_string(l.var_no()));
out << identifier;
if(l.sign())
out << ")";
smt2_identifiers.insert(identifier);
}
}
void smt2_convt::push()
{
UNIMPLEMENTED;
}
void smt2_convt::push(const std::vector<exprt> &_assumptions)
{
INVARIANT(assumptions.empty(), "nested contexts are not supported");
assumptions.reserve(_assumptions.size());
for(auto &assumption : _assumptions)
assumptions.push_back(convert(assumption));
}
void smt2_convt::pop()