Check in LLVM r95781.
diff --git a/lib/Checker/SimpleSValuator.cpp b/lib/Checker/SimpleSValuator.cpp
new file mode 100644
index 0000000..fb1d74a
--- /dev/null
+++ b/lib/Checker/SimpleSValuator.cpp
@@ -0,0 +1,428 @@
+// SimpleSValuator.cpp - A basic SValuator ------------------------*- 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 SimpleSValuator, a basic implementation of SValuator.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Checker/PathSensitive/SValuator.h"
+#include "clang/Checker/PathSensitive/GRState.h"
+
+using namespace clang;
+
+namespace {
+class SimpleSValuator : public SValuator {
+protected:
+ virtual SVal EvalCastNL(NonLoc val, QualType castTy);
+ virtual SVal EvalCastL(Loc val, QualType castTy);
+
+public:
+ SimpleSValuator(ValueManager &valMgr) : SValuator(valMgr) {}
+ virtual ~SimpleSValuator() {}
+
+ virtual SVal EvalMinus(NonLoc val);
+ virtual SVal EvalComplement(NonLoc val);
+ virtual SVal EvalBinOpNN(const GRState *state, BinaryOperator::Opcode op,
+ NonLoc lhs, NonLoc rhs, QualType resultTy);
+ virtual SVal EvalBinOpLL(BinaryOperator::Opcode op, Loc lhs, Loc rhs,
+ QualType resultTy);
+ virtual SVal EvalBinOpLN(const GRState *state, BinaryOperator::Opcode op,
+ Loc lhs, NonLoc rhs, QualType resultTy);
+};
+} // end anonymous namespace
+
+SValuator *clang::CreateSimpleSValuator(ValueManager &valMgr) {
+ return new SimpleSValuator(valMgr);
+}
+
+//===----------------------------------------------------------------------===//
+// Transfer function for Casts.
+//===----------------------------------------------------------------------===//
+
+SVal SimpleSValuator::EvalCastNL(NonLoc val, QualType castTy) {
+
+ bool isLocType = Loc::IsLocType(castTy);
+
+ if (nonloc::LocAsInteger *LI = dyn_cast<nonloc::LocAsInteger>(&val)) {
+ if (isLocType)
+ return LI->getLoc();
+
+ // FIXME: Correctly support promotions/truncations.
+ ASTContext &Ctx = ValMgr.getContext();
+ unsigned castSize = Ctx.getTypeSize(castTy);
+ if (castSize == LI->getNumBits())
+ return val;
+
+ return ValMgr.makeLocAsInteger(LI->getLoc(), castSize);
+ }
+
+ if (const SymExpr *se = val.getAsSymbolicExpression()) {
+ ASTContext &Ctx = ValMgr.getContext();
+ QualType T = Ctx.getCanonicalType(se->getType(Ctx));
+ if (T == Ctx.getCanonicalType(castTy))
+ return val;
+
+ // FIXME: Remove this hack when we support symbolic truncation/extension.
+ // HACK: If both castTy and T are integers, ignore the cast. This is
+ // not a permanent solution. Eventually we want to precisely handle
+ // extension/truncation of symbolic integers. This prevents us from losing
+ // precision when we assign 'x = y' and 'y' is symbolic and x and y are
+ // different integer types.
+ if (T->isIntegerType() && castTy->isIntegerType())
+ return val;
+
+ return UnknownVal();
+ }
+
+ if (!isa<nonloc::ConcreteInt>(val))
+ return UnknownVal();
+
+ // Only handle casts from integers to integers.
+ if (!isLocType && !castTy->isIntegerType())
+ return UnknownVal();
+
+ llvm::APSInt i = cast<nonloc::ConcreteInt>(val).getValue();
+ i.setIsUnsigned(castTy->isUnsignedIntegerType() || Loc::IsLocType(castTy));
+ i.extOrTrunc(ValMgr.getContext().getTypeSize(castTy));
+
+ if (isLocType)
+ return ValMgr.makeIntLocVal(i);
+ else
+ return ValMgr.makeIntVal(i);
+}
+
+SVal SimpleSValuator::EvalCastL(Loc val, QualType castTy) {
+
+ // Casts from pointers -> pointers, just return the lval.
+ //
+ // Casts from pointers -> references, just return the lval. These
+ // can be introduced by the frontend for corner cases, e.g
+ // casting from va_list* to __builtin_va_list&.
+ //
+ if (Loc::IsLocType(castTy) || castTy->isReferenceType())
+ return val;
+
+ // FIXME: Handle transparent unions where a value can be "transparently"
+ // lifted into a union type.
+ if (castTy->isUnionType())
+ return UnknownVal();
+
+ assert(castTy->isIntegerType());
+ unsigned BitWidth = ValMgr.getContext().getTypeSize(castTy);
+
+ if (!isa<loc::ConcreteInt>(val))
+ return ValMgr.makeLocAsInteger(val, BitWidth);
+
+ llvm::APSInt i = cast<loc::ConcreteInt>(val).getValue();
+ i.setIsUnsigned(castTy->isUnsignedIntegerType() || Loc::IsLocType(castTy));
+ i.extOrTrunc(BitWidth);
+ return ValMgr.makeIntVal(i);
+}
+
+//===----------------------------------------------------------------------===//
+// Transfer function for unary operators.
+//===----------------------------------------------------------------------===//
+
+SVal SimpleSValuator::EvalMinus(NonLoc val) {
+ switch (val.getSubKind()) {
+ case nonloc::ConcreteIntKind:
+ return cast<nonloc::ConcreteInt>(val).evalMinus(ValMgr);
+ default:
+ return UnknownVal();
+ }
+}
+
+SVal SimpleSValuator::EvalComplement(NonLoc X) {
+ switch (X.getSubKind()) {
+ case nonloc::ConcreteIntKind:
+ return cast<nonloc::ConcreteInt>(X).evalComplement(ValMgr);
+ default:
+ return UnknownVal();
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// Transfer function for binary operators.
+//===----------------------------------------------------------------------===//
+
+static BinaryOperator::Opcode NegateComparison(BinaryOperator::Opcode op) {
+ switch (op) {
+ default:
+ assert(false && "Invalid opcode.");
+ case BinaryOperator::LT: return BinaryOperator::GE;
+ case BinaryOperator::GT: return BinaryOperator::LE;
+ case BinaryOperator::LE: return BinaryOperator::GT;
+ case BinaryOperator::GE: return BinaryOperator::LT;
+ case BinaryOperator::EQ: return BinaryOperator::NE;
+ case BinaryOperator::NE: return BinaryOperator::EQ;
+ }
+}
+
+// Equality operators for Locs.
+// FIXME: All this logic will be revamped when we have MemRegion::getLocation()
+// implemented.
+
+static SVal EvalEquality(ValueManager &ValMgr, Loc lhs, Loc rhs, bool isEqual,
+ QualType resultTy) {
+
+ switch (lhs.getSubKind()) {
+ default:
+ assert(false && "EQ/NE not implemented for this Loc.");
+ return UnknownVal();
+
+ case loc::ConcreteIntKind: {
+ if (SymbolRef rSym = rhs.getAsSymbol())
+ return ValMgr.makeNonLoc(rSym,
+ isEqual ? BinaryOperator::EQ
+ : BinaryOperator::NE,
+ cast<loc::ConcreteInt>(lhs).getValue(),
+ resultTy);
+ break;
+ }
+ case loc::MemRegionKind: {
+ if (SymbolRef lSym = lhs.getAsLocSymbol()) {
+ if (isa<loc::ConcreteInt>(rhs)) {
+ return ValMgr.makeNonLoc(lSym,
+ isEqual ? BinaryOperator::EQ
+ : BinaryOperator::NE,
+ cast<loc::ConcreteInt>(rhs).getValue(),
+ resultTy);
+ }
+ }
+ break;
+ }
+
+ case loc::GotoLabelKind:
+ break;
+ }
+
+ return ValMgr.makeTruthVal(isEqual ? lhs == rhs : lhs != rhs, resultTy);
+}
+
+SVal SimpleSValuator::EvalBinOpNN(const GRState *state,
+ BinaryOperator::Opcode op,
+ NonLoc lhs, NonLoc rhs,
+ QualType resultTy) {
+ // Handle trivial case where left-side and right-side are the same.
+ if (lhs == rhs)
+ switch (op) {
+ default:
+ break;
+ case BinaryOperator::EQ:
+ case BinaryOperator::LE:
+ case BinaryOperator::GE:
+ return ValMgr.makeTruthVal(true, resultTy);
+ case BinaryOperator::LT:
+ case BinaryOperator::GT:
+ case BinaryOperator::NE:
+ return ValMgr.makeTruthVal(false, resultTy);
+ }
+
+ while (1) {
+ switch (lhs.getSubKind()) {
+ default:
+ return UnknownVal();
+ case nonloc::LocAsIntegerKind: {
+ Loc lhsL = cast<nonloc::LocAsInteger>(lhs).getLoc();
+ switch (rhs.getSubKind()) {
+ case nonloc::LocAsIntegerKind:
+ return EvalBinOpLL(op, lhsL, cast<nonloc::LocAsInteger>(rhs).getLoc(),
+ resultTy);
+ case nonloc::ConcreteIntKind: {
+ // Transform the integer into a location and compare.
+ ASTContext& Ctx = ValMgr.getContext();
+ llvm::APSInt i = cast<nonloc::ConcreteInt>(rhs).getValue();
+ i.setIsUnsigned(true);
+ i.extOrTrunc(Ctx.getTypeSize(Ctx.VoidPtrTy));
+ return EvalBinOpLL(op, lhsL, ValMgr.makeLoc(i), resultTy);
+ }
+ default:
+ switch (op) {
+ case BinaryOperator::EQ:
+ return ValMgr.makeTruthVal(false, resultTy);
+ case BinaryOperator::NE:
+ return ValMgr.makeTruthVal(true, resultTy);
+ default:
+ // This case also handles pointer arithmetic.
+ return UnknownVal();
+ }
+ }
+ }
+ case nonloc::SymExprValKind: {
+ // Logical not?
+ if (!(op == BinaryOperator::EQ && rhs.isZeroConstant()))
+ return UnknownVal();
+
+ const SymExpr *symExpr =
+ cast<nonloc::SymExprVal>(lhs).getSymbolicExpression();
+
+ // Only handle ($sym op constant) for now.
+ if (const SymIntExpr *symIntExpr = dyn_cast<SymIntExpr>(symExpr)) {
+ BinaryOperator::Opcode opc = symIntExpr->getOpcode();
+ switch (opc) {
+ case BinaryOperator::LAnd:
+ case BinaryOperator::LOr:
+ assert(false && "Logical operators handled by branching logic.");
+ return UnknownVal();
+ case BinaryOperator::Assign:
+ case BinaryOperator::MulAssign:
+ case BinaryOperator::DivAssign:
+ case BinaryOperator::RemAssign:
+ case BinaryOperator::AddAssign:
+ case BinaryOperator::SubAssign:
+ case BinaryOperator::ShlAssign:
+ case BinaryOperator::ShrAssign:
+ case BinaryOperator::AndAssign:
+ case BinaryOperator::XorAssign:
+ case BinaryOperator::OrAssign:
+ case BinaryOperator::Comma:
+ assert(false && "'=' and ',' operators handled by GRExprEngine.");
+ return UnknownVal();
+ case BinaryOperator::PtrMemD:
+ case BinaryOperator::PtrMemI:
+ assert(false && "Pointer arithmetic not handled here.");
+ return UnknownVal();
+ case BinaryOperator::Mul:
+ case BinaryOperator::Div:
+ case BinaryOperator::Rem:
+ case BinaryOperator::Add:
+ case BinaryOperator::Sub:
+ case BinaryOperator::Shl:
+ case BinaryOperator::Shr:
+ case BinaryOperator::And:
+ case BinaryOperator::Xor:
+ case BinaryOperator::Or:
+ // Not handled yet.
+ return UnknownVal();
+ case BinaryOperator::LT:
+ case BinaryOperator::GT:
+ case BinaryOperator::LE:
+ case BinaryOperator::GE:
+ case BinaryOperator::EQ:
+ case BinaryOperator::NE:
+ opc = NegateComparison(opc);
+ assert(symIntExpr->getType(ValMgr.getContext()) == resultTy);
+ return ValMgr.makeNonLoc(symIntExpr->getLHS(), opc,
+ symIntExpr->getRHS(), resultTy);
+ }
+ }
+ }
+ case nonloc::ConcreteIntKind: {
+ if (isa<nonloc::ConcreteInt>(rhs)) {
+ const nonloc::ConcreteInt& lhsInt = cast<nonloc::ConcreteInt>(lhs);
+ return lhsInt.evalBinOp(ValMgr, op, cast<nonloc::ConcreteInt>(rhs));
+ }
+ else {
+ // Swap the left and right sides and flip the operator if doing so
+ // allows us to better reason about the expression (this is a form
+ // of expression canonicalization).
+ NonLoc tmp = rhs;
+ rhs = lhs;
+ lhs = tmp;
+
+ switch (op) {
+ case BinaryOperator::LT: op = BinaryOperator::GT; continue;
+ case BinaryOperator::GT: op = BinaryOperator::LT; continue;
+ case BinaryOperator::LE: op = BinaryOperator::GE; continue;
+ case BinaryOperator::GE: op = BinaryOperator::LE; continue;
+ case BinaryOperator::EQ:
+ case BinaryOperator::NE:
+ case BinaryOperator::Add:
+ case BinaryOperator::Mul:
+ continue;
+ default:
+ return UnknownVal();
+ }
+ }
+ }
+ case nonloc::SymbolValKind: {
+ nonloc::SymbolVal *slhs = cast<nonloc::SymbolVal>(&lhs);
+ SymbolRef Sym = slhs->getSymbol();
+
+ // Does the symbol simplify to a constant? If so, "fold" the constant
+ // by setting 'lhs' to a ConcreteInt and try again.
+ if (Sym->getType(ValMgr.getContext())->isIntegerType())
+ if (const llvm::APSInt *Constant = state->getSymVal(Sym)) {
+ // The symbol evaluates to a constant. If necessary, promote the
+ // folded constant (LHS) to the result type.
+ BasicValueFactory &BVF = ValMgr.getBasicValueFactory();
+ const llvm::APSInt &lhs_I = BVF.Convert(resultTy, *Constant);
+ lhs = nonloc::ConcreteInt(lhs_I);
+
+ // Also promote the RHS (if necessary).
+
+ // For shifts, it necessary promote the RHS to the result type.
+ if (BinaryOperator::isShiftOp(op))
+ continue;
+
+ // Other operators: do an implicit conversion. This shouldn't be
+ // necessary once we support truncation/extension of symbolic values.
+ if (nonloc::ConcreteInt *rhs_I = dyn_cast<nonloc::ConcreteInt>(&rhs)){
+ rhs = nonloc::ConcreteInt(BVF.Convert(resultTy, rhs_I->getValue()));
+ }
+
+ continue;
+ }
+
+ if (isa<nonloc::ConcreteInt>(rhs)) {
+ return ValMgr.makeNonLoc(slhs->getSymbol(), op,
+ cast<nonloc::ConcreteInt>(rhs).getValue(),
+ resultTy);
+ }
+
+ return UnknownVal();
+ }
+ }
+ }
+}
+
+SVal SimpleSValuator::EvalBinOpLL(BinaryOperator::Opcode op, Loc lhs, Loc rhs,
+ QualType resultTy) {
+ switch (op) {
+ default:
+ return UnknownVal();
+ case BinaryOperator::EQ:
+ case BinaryOperator::NE:
+ return EvalEquality(ValMgr, lhs, rhs, op == BinaryOperator::EQ, resultTy);
+ case BinaryOperator::LT:
+ case BinaryOperator::GT:
+ // FIXME: Generalize. For now, just handle the trivial case where
+ // the two locations are identical.
+ if (lhs == rhs)
+ return ValMgr.makeTruthVal(false, resultTy);
+ return UnknownVal();
+ }
+}
+
+SVal SimpleSValuator::EvalBinOpLN(const GRState *state,
+ BinaryOperator::Opcode op,
+ Loc lhs, NonLoc rhs, QualType resultTy) {
+ // Special case: 'rhs' is an integer that has the same width as a pointer and
+ // we are using the integer location in a comparison. Normally this cannot be
+ // triggered, but transfer functions like those for OSCommpareAndSwapBarrier32
+ // can generate comparisons that trigger this code.
+ // FIXME: Are all locations guaranteed to have pointer width?
+ if (BinaryOperator::isEqualityOp(op)) {
+ if (nonloc::ConcreteInt *rhsInt = dyn_cast<nonloc::ConcreteInt>(&rhs)) {
+ const llvm::APSInt *x = &rhsInt->getValue();
+ ASTContext &ctx = ValMgr.getContext();
+ if (ctx.getTypeSize(ctx.VoidPtrTy) == x->getBitWidth()) {
+ // Convert the signedness of the integer (if necessary).
+ if (x->isSigned())
+ x = &ValMgr.getBasicValueFactory().getValue(*x, true);
+
+ return EvalBinOpLL(op, lhs, loc::ConcreteInt(*x), resultTy);
+ }
+ }
+ }
+
+ // Delegate pointer arithmetic to the StoreManager.
+ return state->getStateManager().getStoreManager().EvalBinOp(op, lhs,
+ rhs, resultTy);
+}