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Diffstat (limited to 'lib/Expr/ExprSMTLIBPrinter.cpp')
| -rw-r--r-- | lib/Expr/ExprSMTLIBPrinter.cpp | 906 |
1 files changed, 906 insertions, 0 deletions
diff --git a/lib/Expr/ExprSMTLIBPrinter.cpp b/lib/Expr/ExprSMTLIBPrinter.cpp new file mode 100644 index 00000000..aa75629a --- /dev/null +++ b/lib/Expr/ExprSMTLIBPrinter.cpp @@ -0,0 +1,906 @@ +//===-- 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(); + mangleQuery(); + } + + 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::mangleQuery() + { + //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"; + } +} + +} + + + |