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//===-- Solver.cpp --------------------------------------------------------===//
//
// The KLEE Symbolic Virtual Machine
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "klee/Solver/Solver.h"
#include "klee/Expr/Constraints.h"
#include "klee/Solver/SolverImpl.h"
#include <utility>
using namespace klee;
const char *Solver::validity_to_str(Validity v) {
switch (v) {
default: return "Unknown";
case True: return "True";
case False: return "False";
}
}
Solver::Solver(std::unique_ptr<SolverImpl> impl) : impl(std::move(impl)) {}
Solver::~Solver() = default;
std::string Solver::getConstraintLog(const Query& query) {
return impl->getConstraintLog(query);
}
void Solver::setCoreSolverTimeout(time::Span timeout) {
impl->setCoreSolverTimeout(timeout);
}
bool Solver::evaluate(const Query& query, Validity &result) {
assert(query.expr->getWidth() == Expr::Bool && "Invalid expression type!");
// Maintain invariants implementations expect.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(query.expr)) {
result = CE->isTrue() ? True : False;
return true;
}
return impl->computeValidity(query, result);
}
bool Solver::mustBeTrue(const Query& query, bool &result) {
assert(query.expr->getWidth() == Expr::Bool && "Invalid expression type!");
// Maintain invariants implementations expect.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(query.expr)) {
result = CE->isTrue() ? true : false;
return true;
}
return impl->computeTruth(query, result);
}
bool Solver::mustBeFalse(const Query& query, bool &result) {
return mustBeTrue(query.negateExpr(), result);
}
bool Solver::mayBeTrue(const Query& query, bool &result) {
bool res;
if (!mustBeFalse(query, res))
return false;
result = !res;
return true;
}
bool Solver::mayBeFalse(const Query& query, bool &result) {
bool res;
if (!mustBeTrue(query, res))
return false;
result = !res;
return true;
}
bool Solver::getValue(const Query& query, ref<ConstantExpr> &result) {
// Maintain invariants implementation expect.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(query.expr)) {
result = CE;
return true;
}
// FIXME: Push ConstantExpr requirement down.
ref<Expr> tmp;
if (!impl->computeValue(query, tmp))
return false;
result = cast<ConstantExpr>(tmp);
return true;
}
bool
Solver::getInitialValues(const Query& query,
const std::vector<const Array*> &objects,
std::vector< std::vector<unsigned char> > &values) {
bool hasSolution;
bool success =
impl->computeInitialValues(query, objects, values, hasSolution);
// FIXME: Propagate this out.
if (!hasSolution)
return false;
return success;
}
std::pair< ref<Expr>, ref<Expr> > Solver::getRange(const Query& query) {
ref<Expr> e = query.expr;
Expr::Width width = e->getWidth();
uint64_t min, max;
if (width==1) {
Solver::Validity result;
if (!evaluate(query, result))
assert(0 && "computeValidity failed");
switch (result) {
case Solver::True:
min = max = 1; break;
case Solver::False:
min = max = 0; break;
default:
min = 0, max = 1; break;
}
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(e)) {
min = max = CE->getZExtValue();
} else {
// binary search for # of useful bits
uint64_t lo=0, hi=width, mid, bits=0;
while (lo<hi) {
mid = lo + (hi - lo)/2;
bool res;
bool success =
mustBeTrue(query.withExpr(
EqExpr::create(LShrExpr::create(e,
ConstantExpr::create(mid,
width)),
ConstantExpr::create(0, width))),
res);
assert(success && "FIXME: Unhandled solver failure");
(void) success;
if (res) {
hi = mid;
} else {
lo = mid+1;
}
bits = lo;
}
// could binary search for training zeros and offset
// min max but unlikely to be very useful
// check common case
bool res = false;
bool success =
mayBeTrue(query.withExpr(EqExpr::create(e, ConstantExpr::create(0,
width))),
res);
assert(success && "FIXME: Unhandled solver failure");
(void) success;
if (res) {
min = 0;
} else {
// binary search for min
lo=0, hi=bits64::maxValueOfNBits(bits);
while (lo<hi) {
mid = lo + (hi - lo)/2;
bool res = false;
bool success =
mayBeTrue(query.withExpr(UleExpr::create(e,
ConstantExpr::create(mid,
width))),
res);
assert(success && "FIXME: Unhandled solver failure");
(void) success;
if (res) {
hi = mid;
} else {
lo = mid+1;
}
}
min = lo;
}
// binary search for max
lo=min, hi=bits64::maxValueOfNBits(bits);
while (lo<hi) {
mid = lo + (hi - lo)/2;
bool res;
bool success =
mustBeTrue(query.withExpr(UleExpr::create(e,
ConstantExpr::create(mid,
width))),
res);
assert(success && "FIXME: Unhandled solver failure");
(void) success;
if (res) {
hi = mid;
} else {
lo = mid+1;
}
}
max = lo;
}
return std::make_pair(ConstantExpr::create(min, width),
ConstantExpr::create(max, width));
}
void Query::dump() const {
llvm::errs() << "Constraints [\n";
for (const auto &constraint : constraints)
constraint->dump();
llvm::errs() << "]\n";
llvm::errs() << "Query [\n";
expr->dump();
llvm::errs() << "]\n";
}
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