llvm-project/clang/lib/StaticAnalyzer/Core/SVals.cpp

323 lines
10 KiB
C++

//= RValues.cpp - Abstract RValues for Path-Sens. Value Tracking -*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines SVal, Loc, and NonLoc, classes that represent
// abstract r-values for use with path-sensitive value tracking.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
#include "clang/AST/ExprObjC.h"
#include "clang/Basic/IdentifierTable.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
using namespace ento;
using llvm::APSInt;
//===----------------------------------------------------------------------===//
// Symbol iteration within an SVal.
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// Utility methods.
//===----------------------------------------------------------------------===//
bool SVal::hasConjuredSymbol() const {
if (Optional<nonloc::SymbolVal> SV = getAs<nonloc::SymbolVal>()) {
SymbolRef sym = SV->getSymbol();
if (isa<SymbolConjured>(sym))
return true;
}
if (Optional<loc::MemRegionVal> RV = getAs<loc::MemRegionVal>()) {
const MemRegion *R = RV->getRegion();
if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
SymbolRef sym = SR->getSymbol();
if (isa<SymbolConjured>(sym))
return true;
}
}
return false;
}
const FunctionDecl *SVal::getAsFunctionDecl() const {
if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {
const MemRegion* R = X->getRegion();
if (const FunctionTextRegion *CTR = R->getAs<FunctionTextRegion>())
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CTR->getDecl()))
return FD;
}
return nullptr;
}
/// \brief If this SVal is a location (subclasses Loc) and wraps a symbol,
/// return that SymbolRef. Otherwise return 0.
///
/// Implicit casts (ex: void* -> char*) can turn Symbolic region into Element
/// region. If that is the case, gets the underlining region.
/// When IncludeBaseRegions is set to true and the SubRegion is non-symbolic,
/// the first symbolic parent region is returned.
SymbolRef SVal::getAsLocSymbol(bool IncludeBaseRegions) const {
// FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())
return X->getLoc().getAsLocSymbol();
if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {
const MemRegion *R = X->getRegion();
if (const SymbolicRegion *SymR = IncludeBaseRegions ?
R->getSymbolicBase() :
dyn_cast<SymbolicRegion>(R->StripCasts()))
return SymR->getSymbol();
}
return nullptr;
}
/// Get the symbol in the SVal or its base region.
SymbolRef SVal::getLocSymbolInBase() const {
Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>();
if (!X)
return nullptr;
const MemRegion *R = X->getRegion();
while (const SubRegion *SR = dyn_cast<SubRegion>(R)) {
if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(SR))
return SymR->getSymbol();
else
R = SR->getSuperRegion();
}
return nullptr;
}
// TODO: The next 3 functions have to be simplified.
/// \brief If this SVal wraps a symbol return that SymbolRef.
/// Otherwise, return 0.
///
/// Casts are ignored during lookup.
/// \param IncludeBaseRegions The boolean that controls whether the search
/// should continue to the base regions if the region is not symbolic.
SymbolRef SVal::getAsSymbol(bool IncludeBaseRegion) const {
// FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>())
return X->getSymbol();
return getAsLocSymbol(IncludeBaseRegion);
}
/// getAsSymbolicExpression - If this Sval wraps a symbolic expression then
/// return that expression. Otherwise return NULL.
const SymExpr *SVal::getAsSymbolicExpression() const {
if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>())
return X->getSymbol();
return getAsSymbol();
}
const SymExpr* SVal::getAsSymExpr() const {
const SymExpr* Sym = getAsSymbol();
if (!Sym)
Sym = getAsSymbolicExpression();
return Sym;
}
const MemRegion *SVal::getAsRegion() const {
if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>())
return X->getRegion();
if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())
return X->getLoc().getAsRegion();
return nullptr;
}
const MemRegion *loc::MemRegionVal::stripCasts(bool StripBaseCasts) const {
const MemRegion *R = getRegion();
return R ? R->StripCasts(StripBaseCasts) : nullptr;
}
const void *nonloc::LazyCompoundVal::getStore() const {
return static_cast<const LazyCompoundValData*>(Data)->getStore();
}
const TypedValueRegion *nonloc::LazyCompoundVal::getRegion() const {
return static_cast<const LazyCompoundValData*>(Data)->getRegion();
}
//===----------------------------------------------------------------------===//
// Other Iterators.
//===----------------------------------------------------------------------===//
nonloc::CompoundVal::iterator nonloc::CompoundVal::begin() const {
return getValue()->begin();
}
nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const {
return getValue()->end();
}
//===----------------------------------------------------------------------===//
// Useful predicates.
//===----------------------------------------------------------------------===//
bool SVal::isConstant() const {
return getAs<nonloc::ConcreteInt>() || getAs<loc::ConcreteInt>();
}
bool SVal::isConstant(int I) const {
if (Optional<loc::ConcreteInt> LV = getAs<loc::ConcreteInt>())
return LV->getValue() == I;
if (Optional<nonloc::ConcreteInt> NV = getAs<nonloc::ConcreteInt>())
return NV->getValue() == I;
return false;
}
bool SVal::isZeroConstant() const {
return isConstant(0);
}
//===----------------------------------------------------------------------===//
// Transfer function dispatch for Non-Locs.
//===----------------------------------------------------------------------===//
SVal nonloc::ConcreteInt::evalBinOp(SValBuilder &svalBuilder,
BinaryOperator::Opcode Op,
const nonloc::ConcreteInt& R) const {
const llvm::APSInt* X =
svalBuilder.getBasicValueFactory().evalAPSInt(Op, getValue(), R.getValue());
if (X)
return nonloc::ConcreteInt(*X);
else
return UndefinedVal();
}
nonloc::ConcreteInt
nonloc::ConcreteInt::evalComplement(SValBuilder &svalBuilder) const {
return svalBuilder.makeIntVal(~getValue());
}
nonloc::ConcreteInt
nonloc::ConcreteInt::evalMinus(SValBuilder &svalBuilder) const {
return svalBuilder.makeIntVal(-getValue());
}
//===----------------------------------------------------------------------===//
// Transfer function dispatch for Locs.
//===----------------------------------------------------------------------===//
SVal loc::ConcreteInt::evalBinOp(BasicValueFactory& BasicVals,
BinaryOperator::Opcode Op,
const loc::ConcreteInt& R) const {
assert(BinaryOperator::isComparisonOp(Op) || Op == BO_Sub);
const llvm::APSInt *X = BasicVals.evalAPSInt(Op, getValue(), R.getValue());
if (X)
return nonloc::ConcreteInt(*X);
else
return UndefinedVal();
}
//===----------------------------------------------------------------------===//
// Pretty-Printing.
//===----------------------------------------------------------------------===//
void SVal::dump() const { dumpToStream(llvm::errs()); }
void SVal::dumpToStream(raw_ostream &os) const {
switch (getBaseKind()) {
case UnknownKind:
os << "Unknown";
break;
case NonLocKind:
castAs<NonLoc>().dumpToStream(os);
break;
case LocKind:
castAs<Loc>().dumpToStream(os);
break;
case UndefinedKind:
os << "Undefined";
break;
}
}
void NonLoc::dumpToStream(raw_ostream &os) const {
switch (getSubKind()) {
case nonloc::ConcreteIntKind: {
const nonloc::ConcreteInt& C = castAs<nonloc::ConcreteInt>();
if (C.getValue().isUnsigned())
os << C.getValue().getZExtValue();
else
os << C.getValue().getSExtValue();
os << ' ' << (C.getValue().isUnsigned() ? 'U' : 'S')
<< C.getValue().getBitWidth() << 'b';
break;
}
case nonloc::SymbolValKind: {
os << castAs<nonloc::SymbolVal>().getSymbol();
break;
}
case nonloc::LocAsIntegerKind: {
const nonloc::LocAsInteger& C = castAs<nonloc::LocAsInteger>();
os << C.getLoc() << " [as " << C.getNumBits() << " bit integer]";
break;
}
case nonloc::CompoundValKind: {
const nonloc::CompoundVal& C = castAs<nonloc::CompoundVal>();
os << "compoundVal{";
bool first = true;
for (nonloc::CompoundVal::iterator I=C.begin(), E=C.end(); I!=E; ++I) {
if (first) {
os << ' '; first = false;
}
else
os << ", ";
(*I).dumpToStream(os);
}
os << "}";
break;
}
case nonloc::LazyCompoundValKind: {
const nonloc::LazyCompoundVal &C = castAs<nonloc::LazyCompoundVal>();
os << "lazyCompoundVal{" << const_cast<void *>(C.getStore())
<< ',' << C.getRegion()
<< '}';
break;
}
default:
assert (false && "Pretty-printed not implemented for this NonLoc.");
break;
}
}
void Loc::dumpToStream(raw_ostream &os) const {
switch (getSubKind()) {
case loc::ConcreteIntKind:
os << castAs<loc::ConcreteInt>().getValue().getZExtValue() << " (Loc)";
break;
case loc::GotoLabelKind:
os << "&&" << castAs<loc::GotoLabel>().getLabel()->getName();
break;
case loc::MemRegionKind:
os << '&' << castAs<loc::MemRegionVal>().getRegion()->getString();
break;
default:
llvm_unreachable("Pretty-printing not implemented for this Loc.");
}
}