summaryrefslogtreecommitdiff
path: root/klee/lib/Expr/ExprSMTLIBPrinter.cpp
blob: 9e97a4e0894e2167b35c0d4e92ed99c9655385b7 (plain)
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
//===-- ExprSMTLIBPrinter.cpp ------------------------------------------*- C++ -*-===//
//
//                     The KLEE Symbolic Virtual Machine
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include <iostream>

#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "klee/util/ExprSMTLIBPrinter.h"

using namespace std;

namespace ExprSMTLIBOptions
{
	//Command line options
	llvm::cl::opt<klee::ExprSMTLIBPrinter::ConstantDisplayMode> argConstantDisplayMode
	("smtlib-display-constants", llvm::cl::desc("Sets how bitvector constants are written in generated SMT-LIBv2 files (default=dec)"),
	llvm::cl::values( clEnumValN(klee::ExprSMTLIBPrinter::BINARY, "bin","Use binary form (e.g. #b00101101)"),
					  clEnumValN(klee::ExprSMTLIBPrinter::HEX, "hex","Use Hexadecimal form (e.g. #x2D)"),
					  clEnumValN(klee::ExprSMTLIBPrinter::DECIMAL, "dec","Use decimal form (e.g. (_ bv45 8) )"),
					  clEnumValEnd
					),
					llvm::cl::init(klee::ExprSMTLIBPrinter::DECIMAL)


	);

	llvm::cl::opt<bool> humanReadableSMTLIB("smtlib-human-readable",
				llvm::cl::desc("Enables generated SMT-LIBv2 files to be human readable (default=off)"),
				llvm::cl::init(false)


	);

}


namespace klee
{

	ExprSMTLIBPrinter::ExprSMTLIBPrinter() :
		usedArrays(), o(NULL), query(NULL), p(NULL), haveConstantArray(false), logicToUse(QF_AUFBV),
		humanReadable(ExprSMTLIBOptions::humanReadableSMTLIB), smtlibBoolOptions(), arraysToCallGetValueOn(NULL)
	{
		setConstantDisplayMode(ExprSMTLIBOptions::argConstantDisplayMode);
	}

	ExprSMTLIBPrinter::~ExprSMTLIBPrinter()
	{
		if(p!=NULL)
			delete p;
	}

	void ExprSMTLIBPrinter::setOutput(std::ostream& output)
	{
		o = &output;
		if(p!=NULL)
			delete p;

		p = new PrintContext(output);
	}

	void ExprSMTLIBPrinter::setQuery(const Query& q)
	{
		query = &q;
		reset(); // clear the data structures
		scanAll();
		negateQueryExpression();
	}

	void ExprSMTLIBPrinter::reset()
	{
		usedArrays.clear();
		haveConstantArray=false;

		/* Clear the PRODUCE_MODELS option if it was automatically set.
		 * We need to do this because the next query might not need the
		 * (get-value) SMT-LIBv2 command.
		 */
		if(arraysToCallGetValueOn !=NULL)
			setSMTLIBboolOption(PRODUCE_MODELS,OPTION_DEFAULT);

		arraysToCallGetValueOn=NULL;


	}

	bool ExprSMTLIBPrinter::isHumanReadable()
	{
		return humanReadable;
	}

	bool ExprSMTLIBPrinter::setConstantDisplayMode(ConstantDisplayMode cdm)
	{
		if(cdm > DECIMAL)
			return false;

		this->cdm = cdm;
		return true;
	}

	void ExprSMTLIBPrinter::printConstant(const ref<ConstantExpr>& e)
	{
		/* Handle simple boolean constants */

		if(e->isTrue())
		{
			*p << "true";
			return;
		}

		if(e->isFalse())
		{
			*p << "false";
			return;
		}

		/* Handle bitvector constants */

		std::string value;

		/* SMTLIBv2 deduces the bit-width (should be 8-bits in our case)
		 * from the length of the string (e.g. zero is #b00000000). LLVM
		 * doesn't know about this so we need to pad the printed output
		 * with the appropriate number of zeros (zeroPad)
		 */
		unsigned int zeroPad=0;

		switch(cdm)
		{
			case BINARY:
				e->toString(value,2);
				*p << "#b";

				zeroPad = e->getWidth() - value.length();

				for(unsigned int count=0; count < zeroPad; count++)
					*p << "0";

				*p << value ;
				break;

			case HEX:
				e->toString(value,16);
				*p << "#x";

				zeroPad =  (e->getWidth() / 4) - value.length();
				for(unsigned int count=0; count < zeroPad; count++)
					*p << "0";

				*p << value ;
				break;

			case DECIMAL:
				e->toString(value,10);
				*p << "(_ bv" << value<< " " << e->getWidth() << ")";
				break;

			default:
				std::cerr << "ExprSMTLIBPrinter::printConstant() : Unexpected Constant display mode" << std::endl;
		}
	}

	void ExprSMTLIBPrinter::printExpression(const ref<Expr>& e, ExprSMTLIBPrinter::SMTLIB_SORT expectedSort)
	{
		//check if casting might be necessary
		if(getSort(e) != expectedSort)
		{
			printCastToSort(e,expectedSort);
			return;
		}


		switch(e->getKind())
		{
			case Expr::Constant:
				printConstant(cast<ConstantExpr>(e));
				return; //base case

			case Expr::NotOptimized:
				//skip to child
				printExpression(e->getKid(0),expectedSort);
				return;

			case Expr::Read:
				printReadExpr(cast<ReadExpr>(e));
				return;

			case Expr::Extract:
				printExtractExpr(cast<ExtractExpr>(e));
				return;

			case Expr::SExt:
			case Expr::ZExt:
				printCastExpr(cast<CastExpr>(e));
				return;

			case Expr::Ne:
				printNotEqualExpr(cast<NeExpr>(e));
				return;

			case Expr::Select:
				//the if-then-else expression.
				printSelectExpr(cast<SelectExpr>(e),expectedSort);
				return;

			case Expr::Eq:
				/* The "=" operator is special in that it can take any sort but we must
				 * enforce that both arguments are the same type. We do this a lazy way
				 * by enforcing the second argument is of the same type as the first.
				 */
				printSortArgsExpr(e,getSort(e->getKid(0)));

				return;

			case Expr::And:
			case Expr::Or:
			case Expr::Xor:
			case Expr::Not:
				/* These operators have a bitvector version and a bool version.
				 * For these operators only (e.g. wouldn't apply to bvult) if the expected sort the
				 * expression is T then that implies the arguments are also of type T.
				 */
				printLogicalOrBitVectorExpr(e,expectedSort);

				return;


			default:
				/* The remaining operators (Add,Sub...,Ult,Ule,..)
				 * Expect SORT_BITVECTOR arguments
				 */
				printSortArgsExpr(e,SORT_BITVECTOR);
				return;
		}
	}

	void ExprSMTLIBPrinter::printReadExpr(const ref<ReadExpr>& e)
	{
		*p << "(" << getSMTLIBKeyword(e) << " ";
		p->pushIndent();

		printSeperator();

		//print array with updates recursively
		printUpdatesAndArray(e->updates.head,e->updates.root);

		//print index
		printSeperator();
		printExpression(e->index,SORT_BITVECTOR);

		p->popIndent();
		printSeperator();
		*p << ")";
	}

	void ExprSMTLIBPrinter::printExtractExpr(const ref<ExtractExpr>& e)
	{
		unsigned int lowIndex= e->offset;
		unsigned int highIndex= lowIndex + e->width -1;

		*p << "((_ " << getSMTLIBKeyword(e) << " " << highIndex << "  " << lowIndex << ") ";

		p->pushIndent(); //add indent for recursive call
		printSeperator();

		//recurse
		printExpression(e->getKid(0),SORT_BITVECTOR);

		p->popIndent(); //pop indent added for the recursive call
		printSeperator();
		*p << ")";
	}

	void ExprSMTLIBPrinter::printCastExpr(const ref<CastExpr>& e)
	{
		/* sign_extend and zero_extend behave slightly unusually in SMTLIBv2
		 * instead of specifying of what bit-width we would like to extend to
		 * we specify how many bits to add to the child expression
		 *
		 * e.g
		 * ((_ sign_extend 64) (_ bv5 32))
		 *
		 * gives a (_ BitVec 96) instead of (_ BitVec 64)
		 *
		 * So we must work out how many bits we need to add.
		 *
		 * (e->width) is the desired number of bits
		 * (e->src->getWidth()) is the number of bits in the child
		 */
		unsigned int numExtraBits= (e->width) - (e->src->getWidth());

		*p << "((_ " << getSMTLIBKeyword(e) << " " <<
				numExtraBits << ") ";

		p->pushIndent(); //add indent for recursive call
		printSeperator();

		//recurse
		printExpression(e->src,SORT_BITVECTOR);

		p->popIndent(); //pop indent added for recursive call
		printSeperator();

		*p << ")";
	}

	void ExprSMTLIBPrinter::printNotEqualExpr(const ref<NeExpr>& e)
	{
		*p << "(not (";
		p->pushIndent();
		*p << "=" << " ";
		p->pushIndent();
		printSeperator();

		/* The "=" operators allows both sorts. We assume
		 * that the second argument sort should be forced to be the same sort as the
		 * first argument
		 */
		SMTLIB_SORT s = getSort(e->getKid(0));

		printExpression(e->getKid(0),s);
		printSeperator();
		printExpression(e->getKid(1),s);
		p->popIndent();
		printSeperator();

		*p << ")";
		p->popIndent();
		printSeperator();
		*p << ")";
	}


	const char* ExprSMTLIBPrinter::getSMTLIBKeyword(const ref<Expr>& e)
	{

		switch(e->getKind())
		{
			case Expr::Read: return "select";
			case Expr::Select: return "ite";
			case Expr::Concat: return "concat";
			case Expr::Extract: return "extract";
			case Expr::ZExt: return "zero_extend";
			case Expr::SExt: return "sign_extend";

			case Expr::Add: return "bvadd";
			case Expr::Sub: return "bvsub";
			case Expr::Mul: return "bvmul";
			case Expr::UDiv: return "bvudiv";
			case Expr::SDiv: return "bvsdiv";
			case Expr::URem: return "bvurem";
			case Expr::SRem: return "bvsrem";


			/* And, Xor, Not and Or are not handled here because there different versions
			 * for different sorts. See printLogicalOrBitVectorExpr()
			 */


			case Expr::Shl: return "bvshl";
			case Expr::LShr: return "bvlshr";
			case Expr::AShr: return "bvashr";

			case Expr::Eq: return "=";

			//Not Equal does not exist directly in SMTLIBv2

			case Expr::Ult: return "bvult";
			case Expr::Ule: return "bvule";
			case Expr::Ugt: return "bvugt";
			case Expr::Uge: return "bvuge";

			case Expr::Slt: return "bvslt";
			case Expr::Sle: return "bvsle";
			case Expr::Sgt: return "bvsgt";
			case Expr::Sge: return "bvsge";

			default:
				return "<error>";

		}
	}

	void ExprSMTLIBPrinter::printUpdatesAndArray(const UpdateNode* un, const Array* root)
	{
		if(un!=NULL)
		{
			*p << "(store ";
			p->pushIndent();
			printSeperator();

			//recurse to get the array or update that this store operations applies to
			printUpdatesAndArray(un->next,root);

			printSeperator();

			//print index
			printExpression(un->index,SORT_BITVECTOR);
			printSeperator();

			//print value that is assigned to this index of the array
			printExpression(un->value,SORT_BITVECTOR);

			p->popIndent();
			printSeperator();
			*p << ")";
		}
		else
		{
			//The base case of the recursion
			*p << root->name;
		}

	}

	void ExprSMTLIBPrinter::scanAll()
	{
		//perform scan of all expressions
		for(ConstraintManager::const_iterator i= query->constraints.begin(); i != query->constraints.end(); i++)
			scan(*i);

		//Scan the query too
		scan(query->expr);
	}

	void ExprSMTLIBPrinter::generateOutput()
	{
		if(p==NULL || query == NULL || o ==NULL)
		{
			std::cerr << "ExprSMTLIBPrinter::generateOutput() Can't print SMTLIBv2. Output or query bad!" << std::endl;
			return;
		}

		if(humanReadable) printNotice();
		printOptions();
		printSetLogic();
		printArrayDeclarations();
		printConstraints();
		printQuery();
		printAction();
		printExit();
	}

	void ExprSMTLIBPrinter::printSetLogic()
	{
		*o << "(set-logic ";
		switch(logicToUse)
		{
		case QF_ABV: *o << "QF_ABV"; break;
		case QF_AUFBV: *o << "QF_AUFBV" ; break;
		}
		*o << " )" << std::endl;
	}


	void ExprSMTLIBPrinter::printArrayDeclarations()
	{
		//Assume scan() has been called
		if(humanReadable)
			*o << "; Array declarations" << endl;

		//declare arrays
		for(set<const Array*>::iterator it = usedArrays.begin(); it != usedArrays.end(); it++)
		{
			*o << "(declare-fun " << (*it)->name << " () "
				 "(Array (_ BitVec " << (*it)->getDomain() << ") "
				 "(_ BitVec " << (*it)->getRange() << ") ) )" << endl;
		}

		//Set array values for constant values
		if(haveConstantArray)
		{
			if(humanReadable)
				*o << "; Constant Array Definitions" << endl;

			const Array* array;

			//loop over found arrays
			for(set<const Array*>::iterator it = usedArrays.begin(); it != usedArrays.end(); it++)
			{
				array= *it;
				int byteIndex=0;
				if(array->isConstantArray())
				{
					/*loop over elements in the array and generate an assert statement
					  for each one
					 */
					for(vector< ref<ConstantExpr> >::const_iterator ce= array->constantValues.begin();
							ce != array->constantValues.end(); ce++, byteIndex++)
					{
						*p << "(assert (";
						p->pushIndent();
						*p <<           "= ";
						p->pushIndent();
						printSeperator();

						*p << "(select " << array->name << " (_ bv" << byteIndex << " " << array->getDomain() << ") )";
						printSeperator();
						printConstant((*ce));

						p->popIndent();
						printSeperator();
						*p << ")";
						p->popIndent();
						printSeperator();
						*p << ")";

						p->breakLineI();

					}
				}
			}
		}
	}

	void ExprSMTLIBPrinter::printConstraints()
	{
		if(humanReadable)
			*o << "; Constraints" << endl;

		//Generate assert statements for each constraint
		for(ConstraintManager::const_iterator i= query->constraints.begin(); i != query->constraints.end(); i++)
		{
			*p << "(assert ";
			p->pushIndent();
			printSeperator();

			//recurse into Expression
			printExpression(*i,SORT_BOOL);

			p->popIndent();
			printSeperator();
			*p << ")"; p->breakLineI();
		}

	}

	void ExprSMTLIBPrinter::printAction()
	{
		//Ask solver to check for satisfiability
		*o << "(check-sat)" << endl;

		/* If we has arrays to find the values of then we'll
		 * ask the solver for the value of each bitvector in each array
		 */
		if(arraysToCallGetValueOn!=NULL && !arraysToCallGetValueOn->empty())
		{

			const Array* theArray=0;

			//loop over the array names
			for(vector<const Array*>::const_iterator it = arraysToCallGetValueOn->begin(); it != arraysToCallGetValueOn->end(); it++)
			{
				theArray=*it;
				//Loop over the array indices
				for(unsigned int index=0; index < theArray->size; ++index)
				{
					*o << "(get-value ( (select " << (**it).name <<
					     " (_ bv" << index << " " << theArray->getDomain() << ") ) ) )" << endl;
				}

			}


		}
	}

	void ExprSMTLIBPrinter::scan(const ref<Expr>& e)
	{
		if(e.isNull())
		{
			std::cerr << "ExprSMTLIBPrinter::scan() : Found NULL expression!" << std::endl;
			return;
		}

		if(isa<ConstantExpr>(e))
			return; //we don't need to scan simple constants

		if(const ReadExpr* re = dyn_cast<ReadExpr>(e))
		{

			//Attempt to insert array and if array wasn't present before do more things
			if(usedArrays.insert(re->updates.root).second)
			{

				//check if the array is constant
				if( re->updates.root->isConstantArray())
					haveConstantArray=true;

				//scan the update list
				scanUpdates(re->updates.head);

			}

		}

		//recurse into the children
		Expr* ep = e.get();
		for(unsigned int i=0; i < ep->getNumKids(); i++)
			scan(ep->getKid(i));
	}


	void ExprSMTLIBPrinter::scanUpdates(const UpdateNode* un)
	{
		while(un != NULL)
		{
			scan(un->index);
			scan(un->value);
			un= un->next;
		}
	}


	void ExprSMTLIBPrinter::printExit()
	{
		*o << "(exit)" << endl;
	}

	bool ExprSMTLIBPrinter::setLogic(SMTLIBv2Logic l)
	{
		if(l > QF_AUFBV)
			return false;

		logicToUse=l;
		return true;
	}

	void ExprSMTLIBPrinter::printSeperator()
	{
		if(humanReadable)
			p->breakLineI();
		else
			p->write(" ");
	}

	void ExprSMTLIBPrinter::printNotice()
	{
		*o << "; This file conforms to SMTLIBv2 and was generated by KLEE" << endl;
	}

	void ExprSMTLIBPrinter::setHumanReadable(bool hr)
	{
		humanReadable=hr;
	}

	void ExprSMTLIBPrinter::printOptions()
	{
		//Print out SMTLIBv2 boolean options
		for(std::map<SMTLIBboolOptions,bool>::const_iterator i= smtlibBoolOptions.begin(); i!= smtlibBoolOptions.end(); i++)
		{
			*o << "(set-option :" << getSMTLIBOptionString(i->first) <<
			" " << ((i->second)?"true":"false") << ")" << endl;
		}
	}

	void ExprSMTLIBPrinter::printQuery()
	{
		if(humanReadable)
		{
			*p << "; Query from solver turned into an assert";
			p->breakLineI();
		}

		p->pushIndent();
		*p << "(assert";
		p->pushIndent();
		printSeperator();

		printExpression(queryAssert,SORT_BOOL);

		p->popIndent();
		printSeperator();
		*p << ")";
		p->popIndent();
		p->breakLineI();
	}

	ExprSMTLIBPrinter::SMTLIB_SORT ExprSMTLIBPrinter::getSort(const ref<Expr>& e)
	{
		/* We could handle every operator in a large switch statement,
		 * but this seems more elegant.
		 */

		if(e->getKind() == Expr::Extract)
		{
			/* This is a special corner case. In most cases if a node in the expression tree
			 * is of width 1 it should be considered as SORT_BOOL. However it is possible to
			 * perform an extract operation on a SORT_BITVECTOR and produce a SORT_BITVECTOR of length 1.
			 * The ((_ extract i j) () ) operation in SMTLIBv2 always produces SORT_BITVECTOR
			 */
			return SORT_BITVECTOR;
		}
		else
			return (e->getWidth() == Expr::Bool)?(SORT_BOOL):(SORT_BITVECTOR);
	}

	void ExprSMTLIBPrinter::printCastToSort(const ref<Expr>& e, ExprSMTLIBPrinter::SMTLIB_SORT sort)
	{
		switch(sort)
		{
			case SORT_BITVECTOR:
				if(humanReadable)
				{
					p->breakLineI(); *p << ";Performing implicit bool to bitvector cast"; p->breakLine();
				}
				//We assume the e is a bool that we need to cast to a bitvector sort.
				*p << "(ite"; p->pushIndent(); printSeperator();
				printExpression(e,SORT_BOOL); printSeperator();
				*p << "(_ bv1 1)" ; printSeperator(); //printing the "true" bitvector
				*p << "(_ bv0 1)" ; p->popIndent(); printSeperator(); //printing the "false" bitvector
				*p << ")";
				break;
			case SORT_BOOL:
			{
				/* We make the assumption (might be wrong) that any bitvector whos unsigned decimal value is
				 * is zero is interpreted as "false", otherwise it is true.
				 *
				 * This may not be the interpretation we actually want!
				 */
				Expr::Width bitWidth=e->getWidth();
				if(humanReadable)
				{
					p->breakLineI(); *p << ";Performing implicit bitvector to bool cast"; p->breakLine();
				}
				*p << "(bvugt"; p->pushIndent(); printSeperator();
				// We assume is e is a bitvector
				printExpression(e,SORT_BITVECTOR); printSeperator();
				*p << "(_ bv0 " << bitWidth << ")"; p->popIndent(); printSeperator(); //Zero bitvector of required width
				*p << ")";

				if(bitWidth!=Expr::Bool)
					std::cerr << "ExprSMTLIBPrinter : Warning. Casting a bitvector (length " << bitWidth << ") to bool!" << std::endl;

			}
				break;
			default:
				assert(0 && "Unsupported cast!");
		}
	}

	void ExprSMTLIBPrinter::printSelectExpr(const ref<SelectExpr>& e, ExprSMTLIBPrinter::SMTLIB_SORT s)
	{
		//This is the if-then-else expression

		*p << "(" << getSMTLIBKeyword(e) << " ";
		p->pushIndent(); //add indent for recursive call

			//The condition
			printSeperator();
			printExpression(e->getKid(0),SORT_BOOL);

			/* This operator is special in that the remaining children
			 * can be of any sort.
			 */

			//if true
			printSeperator();
			printExpression(e->getKid(1),s);

			//if false
			printSeperator();
			printExpression(e->getKid(2),s);


		p->popIndent(); //pop indent added for recursive call
		printSeperator();
		*p << ")";
	}

	void ExprSMTLIBPrinter::printSortArgsExpr(const ref<Expr>& e, ExprSMTLIBPrinter::SMTLIB_SORT s)
	{
		*p << "(" << getSMTLIBKeyword(e) << " ";
		p->pushIndent(); //add indent for recursive call

		//loop over children and recurse into each expecting they are of sort "s"
		for(unsigned int i=0; i < e->getNumKids(); i++)
		{
			printSeperator();
			printExpression(e->getKid(i),s);
		}

		p->popIndent(); //pop indent added for recursive call
		printSeperator();
		*p << ")";
	}

	void ExprSMTLIBPrinter::printLogicalOrBitVectorExpr(const ref<Expr>& e, ExprSMTLIBPrinter::SMTLIB_SORT s)
	{
		/* For these operators it is the case that the expected sort is the same as the sorts
		 * of the arguments.
		 */

		*p << "(";
		switch(e->getKind())
		{
			case Expr::And:
				*p << ((s==SORT_BITVECTOR)?"bvand":"and");
				break;
			case Expr::Not:
				*p << ((s==SORT_BITVECTOR)?"bvnot":"not");
				break;
			case Expr::Or:
				*p << ((s==SORT_BITVECTOR)?"bvor":"or");
				break;

			case Expr::Xor:
				*p << ((s==SORT_BITVECTOR)?"bvxor":"xor");
				break;
			default:
				*p << "ERROR"; // this shouldn't happen
		}
		*p << " ";

		p->pushIndent(); //add indent for recursive call

		//loop over children and recurse into each expecting they are of sort "s"
		for(unsigned int i=0; i < e->getNumKids(); i++)
		{
			printSeperator();
			printExpression(e->getKid(i),s);
		}

		p->popIndent(); //pop indent added for recursive call
		printSeperator();
		*p << ")";
	}

	void ExprSMTLIBPrinter::negateQueryExpression()
	{
		//Negating the query
		queryAssert = Expr::createIsZero(query->expr);
	}

	bool ExprSMTLIBPrinter::setSMTLIBboolOption(SMTLIBboolOptions option, SMTLIBboolValues value)
	{
		std::pair< std::map<SMTLIBboolOptions,bool>::iterator, bool> thePair;
		bool theValue=  (value==OPTION_TRUE)?true:false;

		switch(option)
		{
			case PRINT_SUCCESS:
			case PRODUCE_MODELS:
			case INTERACTIVE_MODE:
				thePair=smtlibBoolOptions.insert(std::pair<SMTLIBboolOptions,bool>(option,theValue));

				if(value== OPTION_DEFAULT)
				{
					//we should unset (by removing from map) this option so the solver uses its default
					smtlibBoolOptions.erase(thePair.first);
					return true;
				}

				if(!thePair.second)
				{
					//option was already present so modify instead.
					thePair.first->second=value;
				}
				return true;
			default:
				return false;

		}
	}

	void ExprSMTLIBPrinter::setArrayValuesToGet(const std::vector<const Array*>& a)
	{
		arraysToCallGetValueOn = &a;

		//This option must be set in order to use the SMTLIBv2 command (get-value () )
		if(!a.empty())
			setSMTLIBboolOption(PRODUCE_MODELS,OPTION_TRUE);

		/* There is a risk that users will ask about array values that aren't
		 * even in the query. We should add them to the usedArrays list and hope
		 * that the solver knows what to do when we ask for the values of arrays
		 * that don't feature in our query!
		 */
		for(vector<const Array*>::const_iterator i = a.begin(); i!= a.end() ; ++i)
		{
			usedArrays.insert(*i);
		}

	}

const char* ExprSMTLIBPrinter::getSMTLIBOptionString(ExprSMTLIBPrinter::SMTLIBboolOptions option)
{
	switch(option)
	{
		case PRINT_SUCCESS: return "print-success";
		case PRODUCE_MODELS: return "produce-models";
		case INTERACTIVE_MODE: return "interactive-mode";
		default:
			return "unknown-option";
	}
}

}