| //=-- ExprEngineC.cpp - ExprEngine support for C expressions ----*- 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 ExprEngine's support for C expressions. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/StaticAnalyzer/Core/CheckerManager.h" |
| #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" |
| |
| using namespace clang; |
| using namespace ento; |
| using llvm::APSInt; |
| |
| void ExprEngine::VisitBinaryOperator(const BinaryOperator* B, |
| ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| |
| Expr *LHS = B->getLHS()->IgnoreParens(); |
| Expr *RHS = B->getRHS()->IgnoreParens(); |
| |
| // FIXME: Prechecks eventually go in ::Visit(). |
| ExplodedNodeSet CheckedSet; |
| ExplodedNodeSet Tmp2; |
| getCheckerManager().runCheckersForPreStmt(CheckedSet, Pred, B, *this); |
| |
| // With both the LHS and RHS evaluated, process the operation itself. |
| for (ExplodedNodeSet::iterator it=CheckedSet.begin(), ei=CheckedSet.end(); |
| it != ei; ++it) { |
| |
| ProgramStateRef state = (*it)->getState(); |
| const LocationContext *LCtx = (*it)->getLocationContext(); |
| SVal LeftV = state->getSVal(LHS, LCtx); |
| SVal RightV = state->getSVal(RHS, LCtx); |
| |
| BinaryOperator::Opcode Op = B->getOpcode(); |
| |
| if (Op == BO_Assign) { |
| // EXPERIMENTAL: "Conjured" symbols. |
| // FIXME: Handle structs. |
| if (RightV.isUnknown()) { |
| unsigned Count = currentBuilderContext->getCurrentBlockCount(); |
| RightV = svalBuilder.getConjuredSymbolVal(NULL, B->getRHS(), Count); |
| } |
| // Simulate the effects of a "store": bind the value of the RHS |
| // to the L-Value represented by the LHS. |
| SVal ExprVal = B->isLValue() ? LeftV : RightV; |
| evalStore(Tmp2, B, LHS, *it, state->BindExpr(B, LCtx, ExprVal), |
| LeftV, RightV); |
| continue; |
| } |
| |
| if (!B->isAssignmentOp()) { |
| StmtNodeBuilder Bldr(*it, Tmp2, *currentBuilderContext); |
| // Process non-assignments except commas or short-circuited |
| // logical expressions (LAnd and LOr). |
| SVal Result = evalBinOp(state, Op, LeftV, RightV, B->getType()); |
| if (Result.isUnknown()) { |
| Bldr.generateNode(B, *it, state); |
| continue; |
| } |
| |
| state = state->BindExpr(B, LCtx, Result); |
| Bldr.generateNode(B, *it, state); |
| continue; |
| } |
| |
| assert (B->isCompoundAssignmentOp()); |
| |
| switch (Op) { |
| default: |
| llvm_unreachable("Invalid opcode for compound assignment."); |
| case BO_MulAssign: Op = BO_Mul; break; |
| case BO_DivAssign: Op = BO_Div; break; |
| case BO_RemAssign: Op = BO_Rem; break; |
| case BO_AddAssign: Op = BO_Add; break; |
| case BO_SubAssign: Op = BO_Sub; break; |
| case BO_ShlAssign: Op = BO_Shl; break; |
| case BO_ShrAssign: Op = BO_Shr; break; |
| case BO_AndAssign: Op = BO_And; break; |
| case BO_XorAssign: Op = BO_Xor; break; |
| case BO_OrAssign: Op = BO_Or; break; |
| } |
| |
| // Perform a load (the LHS). This performs the checks for |
| // null dereferences, and so on. |
| ExplodedNodeSet Tmp; |
| SVal location = LeftV; |
| evalLoad(Tmp, LHS, *it, state, location); |
| |
| for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end(); I != E; |
| ++I) { |
| |
| state = (*I)->getState(); |
| const LocationContext *LCtx = (*I)->getLocationContext(); |
| SVal V = state->getSVal(LHS, LCtx); |
| |
| // Get the computation type. |
| QualType CTy = |
| cast<CompoundAssignOperator>(B)->getComputationResultType(); |
| CTy = getContext().getCanonicalType(CTy); |
| |
| QualType CLHSTy = |
| cast<CompoundAssignOperator>(B)->getComputationLHSType(); |
| CLHSTy = getContext().getCanonicalType(CLHSTy); |
| |
| QualType LTy = getContext().getCanonicalType(LHS->getType()); |
| |
| // Promote LHS. |
| V = svalBuilder.evalCast(V, CLHSTy, LTy); |
| |
| // Compute the result of the operation. |
| SVal Result = svalBuilder.evalCast(evalBinOp(state, Op, V, RightV, CTy), |
| B->getType(), CTy); |
| |
| // EXPERIMENTAL: "Conjured" symbols. |
| // FIXME: Handle structs. |
| |
| SVal LHSVal; |
| |
| if (Result.isUnknown()) { |
| |
| unsigned Count = currentBuilderContext->getCurrentBlockCount(); |
| |
| // The symbolic value is actually for the type of the left-hand side |
| // expression, not the computation type, as this is the value the |
| // LValue on the LHS will bind to. |
| LHSVal = svalBuilder.getConjuredSymbolVal(NULL, B->getRHS(), LTy, |
| Count); |
| |
| // However, we need to convert the symbol to the computation type. |
| Result = svalBuilder.evalCast(LHSVal, CTy, LTy); |
| } |
| else { |
| // The left-hand side may bind to a different value then the |
| // computation type. |
| LHSVal = svalBuilder.evalCast(Result, LTy, CTy); |
| } |
| |
| // In C++, assignment and compound assignment operators return an |
| // lvalue. |
| if (B->isLValue()) |
| state = state->BindExpr(B, LCtx, location); |
| else |
| state = state->BindExpr(B, LCtx, Result); |
| |
| evalStore(Tmp2, B, LHS, *I, state, location, LHSVal); |
| } |
| } |
| |
| // FIXME: postvisits eventually go in ::Visit() |
| getCheckerManager().runCheckersForPostStmt(Dst, Tmp2, B, *this); |
| } |
| |
| void ExprEngine::VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| |
| CanQualType T = getContext().getCanonicalType(BE->getType()); |
| SVal V = svalBuilder.getBlockPointer(BE->getBlockDecl(), T, |
| Pred->getLocationContext()); |
| |
| ExplodedNodeSet Tmp; |
| StmtNodeBuilder Bldr(Pred, Tmp, *currentBuilderContext); |
| Bldr.generateNode(BE, Pred, |
| Pred->getState()->BindExpr(BE, Pred->getLocationContext(), |
| V), |
| false, 0, |
| ProgramPoint::PostLValueKind); |
| |
| // FIXME: Move all post/pre visits to ::Visit(). |
| getCheckerManager().runCheckersForPostStmt(Dst, Tmp, BE, *this); |
| } |
| |
| void ExprEngine::VisitCast(const CastExpr *CastE, const Expr *Ex, |
| ExplodedNode *Pred, ExplodedNodeSet &Dst) { |
| |
| ExplodedNodeSet dstPreStmt; |
| getCheckerManager().runCheckersForPreStmt(dstPreStmt, Pred, CastE, *this); |
| |
| if (CastE->getCastKind() == CK_LValueToRValue) { |
| for (ExplodedNodeSet::iterator I = dstPreStmt.begin(), E = dstPreStmt.end(); |
| I!=E; ++I) { |
| ExplodedNode *subExprNode = *I; |
| ProgramStateRef state = subExprNode->getState(); |
| const LocationContext *LCtx = subExprNode->getLocationContext(); |
| evalLoad(Dst, CastE, subExprNode, state, state->getSVal(Ex, LCtx)); |
| } |
| return; |
| } |
| |
| // All other casts. |
| QualType T = CastE->getType(); |
| QualType ExTy = Ex->getType(); |
| |
| if (const ExplicitCastExpr *ExCast=dyn_cast_or_null<ExplicitCastExpr>(CastE)) |
| T = ExCast->getTypeAsWritten(); |
| |
| StmtNodeBuilder Bldr(dstPreStmt, Dst, *currentBuilderContext); |
| for (ExplodedNodeSet::iterator I = dstPreStmt.begin(), E = dstPreStmt.end(); |
| I != E; ++I) { |
| |
| Pred = *I; |
| |
| switch (CastE->getCastKind()) { |
| case CK_LValueToRValue: |
| llvm_unreachable("LValueToRValue casts handled earlier."); |
| case CK_ToVoid: |
| continue; |
| // The analyzer doesn't do anything special with these casts, |
| // since it understands retain/release semantics already. |
| case CK_ARCProduceObject: |
| case CK_ARCConsumeObject: |
| case CK_ARCReclaimReturnedObject: |
| case CK_ARCExtendBlockObject: // Fall-through. |
| // The analyser can ignore atomic casts for now, although some future |
| // checkers may want to make certain that you're not modifying the same |
| // value through atomic and nonatomic pointers. |
| case CK_AtomicToNonAtomic: |
| case CK_NonAtomicToAtomic: |
| // True no-ops. |
| case CK_NoOp: |
| case CK_FunctionToPointerDecay: { |
| // Copy the SVal of Ex to CastE. |
| ProgramStateRef state = Pred->getState(); |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| SVal V = state->getSVal(Ex, LCtx); |
| state = state->BindExpr(CastE, LCtx, V); |
| Bldr.generateNode(CastE, Pred, state); |
| continue; |
| } |
| case CK_Dependent: |
| case CK_ArrayToPointerDecay: |
| case CK_BitCast: |
| case CK_LValueBitCast: |
| case CK_IntegralCast: |
| case CK_NullToPointer: |
| case CK_IntegralToPointer: |
| case CK_PointerToIntegral: |
| case CK_PointerToBoolean: |
| case CK_IntegralToBoolean: |
| case CK_IntegralToFloating: |
| case CK_FloatingToIntegral: |
| case CK_FloatingToBoolean: |
| case CK_FloatingCast: |
| case CK_FloatingRealToComplex: |
| case CK_FloatingComplexToReal: |
| case CK_FloatingComplexToBoolean: |
| case CK_FloatingComplexCast: |
| case CK_FloatingComplexToIntegralComplex: |
| case CK_IntegralRealToComplex: |
| case CK_IntegralComplexToReal: |
| case CK_IntegralComplexToBoolean: |
| case CK_IntegralComplexCast: |
| case CK_IntegralComplexToFloatingComplex: |
| case CK_CPointerToObjCPointerCast: |
| case CK_BlockPointerToObjCPointerCast: |
| case CK_AnyPointerToBlockPointerCast: |
| case CK_ObjCObjectLValueCast: { |
| // Delegate to SValBuilder to process. |
| ProgramStateRef state = Pred->getState(); |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| SVal V = state->getSVal(Ex, LCtx); |
| V = svalBuilder.evalCast(V, T, ExTy); |
| state = state->BindExpr(CastE, LCtx, V); |
| Bldr.generateNode(CastE, Pred, state); |
| continue; |
| } |
| case CK_DerivedToBase: |
| case CK_UncheckedDerivedToBase: { |
| // For DerivedToBase cast, delegate to the store manager. |
| ProgramStateRef state = Pred->getState(); |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| SVal val = state->getSVal(Ex, LCtx); |
| val = getStoreManager().evalDerivedToBase(val, T); |
| state = state->BindExpr(CastE, LCtx, val); |
| Bldr.generateNode(CastE, Pred, state); |
| continue; |
| } |
| // Various C++ casts that are not handled yet. |
| case CK_Dynamic: |
| case CK_ToUnion: |
| case CK_BaseToDerived: |
| case CK_NullToMemberPointer: |
| case CK_BaseToDerivedMemberPointer: |
| case CK_DerivedToBaseMemberPointer: |
| case CK_UserDefinedConversion: |
| case CK_ConstructorConversion: |
| case CK_VectorSplat: |
| case CK_MemberPointerToBoolean: { |
| // Recover some path-sensitivty by conjuring a new value. |
| QualType resultType = CastE->getType(); |
| if (CastE->isLValue()) |
| resultType = getContext().getPointerType(resultType); |
| |
| SVal result = |
| svalBuilder.getConjuredSymbolVal(NULL, CastE, resultType, |
| currentBuilderContext->getCurrentBlockCount()); |
| |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| ProgramStateRef state = Pred->getState()->BindExpr(CastE, LCtx, |
| result); |
| Bldr.generateNode(CastE, Pred, state); |
| continue; |
| } |
| } |
| } |
| } |
| |
| void ExprEngine::VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL, |
| ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| StmtNodeBuilder B(Pred, Dst, *currentBuilderContext); |
| |
| const InitListExpr *ILE |
| = cast<InitListExpr>(CL->getInitializer()->IgnoreParens()); |
| |
| ProgramStateRef state = Pred->getState(); |
| SVal ILV = state->getSVal(ILE, Pred->getLocationContext()); |
| const LocationContext *LC = Pred->getLocationContext(); |
| state = state->bindCompoundLiteral(CL, LC, ILV); |
| |
| if (CL->isLValue()) |
| B.generateNode(CL, Pred, state->BindExpr(CL, LC, state->getLValue(CL, LC))); |
| else |
| B.generateNode(CL, Pred, state->BindExpr(CL, LC, ILV)); |
| } |
| |
| void ExprEngine::VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| |
| // FIXME: static variables may have an initializer, but the second |
| // time a function is called those values may not be current. |
| // This may need to be reflected in the CFG. |
| |
| // Assumption: The CFG has one DeclStmt per Decl. |
| const Decl *D = *DS->decl_begin(); |
| |
| if (!D || !isa<VarDecl>(D)) { |
| //TODO:AZ: remove explicit insertion after refactoring is done. |
| Dst.insert(Pred); |
| return; |
| } |
| |
| // FIXME: all pre/post visits should eventually be handled by ::Visit(). |
| ExplodedNodeSet dstPreVisit; |
| getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, DS, *this); |
| |
| StmtNodeBuilder B(dstPreVisit, Dst, *currentBuilderContext); |
| const VarDecl *VD = dyn_cast<VarDecl>(D); |
| for (ExplodedNodeSet::iterator I = dstPreVisit.begin(), E = dstPreVisit.end(); |
| I!=E; ++I) { |
| ExplodedNode *N = *I; |
| ProgramStateRef state = N->getState(); |
| |
| // Decls without InitExpr are not initialized explicitly. |
| const LocationContext *LC = N->getLocationContext(); |
| |
| if (const Expr *InitEx = VD->getInit()) { |
| SVal InitVal = state->getSVal(InitEx, Pred->getLocationContext()); |
| |
| // We bound the temp obj region to the CXXConstructExpr. Now recover |
| // the lazy compound value when the variable is not a reference. |
| if (AMgr.getLangOptions().CPlusPlus && VD->getType()->isRecordType() && |
| !VD->getType()->isReferenceType() && isa<loc::MemRegionVal>(InitVal)){ |
| InitVal = state->getSVal(cast<loc::MemRegionVal>(InitVal).getRegion()); |
| assert(isa<nonloc::LazyCompoundVal>(InitVal)); |
| } |
| |
| // Recover some path-sensitivity if a scalar value evaluated to |
| // UnknownVal. |
| if (InitVal.isUnknown()) { |
| InitVal = svalBuilder.getConjuredSymbolVal(NULL, InitEx, |
| currentBuilderContext->getCurrentBlockCount()); |
| } |
| B.takeNodes(N); |
| ExplodedNodeSet Dst2; |
| evalBind(Dst2, DS, N, state->getLValue(VD, LC), InitVal, true); |
| B.addNodes(Dst2); |
| } |
| else { |
| B.generateNode(DS, N,state->bindDeclWithNoInit(state->getRegion(VD, LC))); |
| } |
| } |
| } |
| |
| void ExprEngine::VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| assert(B->getOpcode() == BO_LAnd || |
| B->getOpcode() == BO_LOr); |
| |
| StmtNodeBuilder Bldr(Pred, Dst, *currentBuilderContext); |
| ProgramStateRef state = Pred->getState(); |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| SVal X = state->getSVal(B, LCtx); |
| assert(X.isUndef()); |
| |
| const Expr *Ex = (const Expr*) cast<UndefinedVal>(X).getData(); |
| assert(Ex); |
| |
| if (Ex == B->getRHS()) { |
| X = state->getSVal(Ex, LCtx); |
| |
| // Handle undefined values. |
| if (X.isUndef()) { |
| Bldr.generateNode(B, Pred, state->BindExpr(B, LCtx, X)); |
| return; |
| } |
| |
| DefinedOrUnknownSVal XD = cast<DefinedOrUnknownSVal>(X); |
| |
| // We took the RHS. Because the value of the '&&' or '||' expression must |
| // evaluate to 0 or 1, we must assume the value of the RHS evaluates to 0 |
| // or 1. Alternatively, we could take a lazy approach, and calculate this |
| // value later when necessary. We don't have the machinery in place for |
| // this right now, and since most logical expressions are used for branches, |
| // the payoff is not likely to be large. Instead, we do eager evaluation. |
| if (ProgramStateRef newState = state->assume(XD, true)) |
| Bldr.generateNode(B, Pred, |
| newState->BindExpr(B, LCtx, |
| svalBuilder.makeIntVal(1U, B->getType()))); |
| |
| if (ProgramStateRef newState = state->assume(XD, false)) |
| Bldr.generateNode(B, Pred, |
| newState->BindExpr(B, LCtx, |
| svalBuilder.makeIntVal(0U, B->getType()))); |
| } |
| else { |
| // We took the LHS expression. Depending on whether we are '&&' or |
| // '||' we know what the value of the expression is via properties of |
| // the short-circuiting. |
| X = svalBuilder.makeIntVal(B->getOpcode() == BO_LAnd ? 0U : 1U, |
| B->getType()); |
| Bldr.generateNode(B, Pred, state->BindExpr(B, LCtx, X)); |
| } |
| } |
| |
| void ExprEngine::VisitInitListExpr(const InitListExpr *IE, |
| ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| StmtNodeBuilder B(Pred, Dst, *currentBuilderContext); |
| |
| ProgramStateRef state = Pred->getState(); |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| QualType T = getContext().getCanonicalType(IE->getType()); |
| unsigned NumInitElements = IE->getNumInits(); |
| |
| if (T->isArrayType() || T->isRecordType() || T->isVectorType()) { |
| llvm::ImmutableList<SVal> vals = getBasicVals().getEmptySValList(); |
| |
| // Handle base case where the initializer has no elements. |
| // e.g: static int* myArray[] = {}; |
| if (NumInitElements == 0) { |
| SVal V = svalBuilder.makeCompoundVal(T, vals); |
| B.generateNode(IE, Pred, state->BindExpr(IE, LCtx, V)); |
| return; |
| } |
| |
| for (InitListExpr::const_reverse_iterator it = IE->rbegin(), |
| ei = IE->rend(); it != ei; ++it) { |
| vals = getBasicVals().consVals(state->getSVal(cast<Expr>(*it), LCtx), |
| vals); |
| } |
| |
| B.generateNode(IE, Pred, |
| state->BindExpr(IE, LCtx, |
| svalBuilder.makeCompoundVal(T, vals))); |
| return; |
| } |
| |
| if (Loc::isLocType(T) || T->isIntegerType()) { |
| assert(IE->getNumInits() == 1); |
| const Expr *initEx = IE->getInit(0); |
| B.generateNode(IE, Pred, state->BindExpr(IE, LCtx, |
| state->getSVal(initEx, LCtx))); |
| return; |
| } |
| |
| llvm_unreachable("unprocessed InitListExpr type"); |
| } |
| |
| void ExprEngine::VisitGuardedExpr(const Expr *Ex, |
| const Expr *L, |
| const Expr *R, |
| ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| StmtNodeBuilder B(Pred, Dst, *currentBuilderContext); |
| |
| ProgramStateRef state = Pred->getState(); |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| SVal X = state->getSVal(Ex, LCtx); |
| assert (X.isUndef()); |
| const Expr *SE = (Expr*) cast<UndefinedVal>(X).getData(); |
| assert(SE); |
| X = state->getSVal(SE, LCtx); |
| |
| // Make sure that we invalidate the previous binding. |
| B.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, X, true)); |
| } |
| |
| void ExprEngine:: |
| VisitOffsetOfExpr(const OffsetOfExpr *OOE, |
| ExplodedNode *Pred, ExplodedNodeSet &Dst) { |
| StmtNodeBuilder B(Pred, Dst, *currentBuilderContext); |
| APSInt IV; |
| if (OOE->EvaluateAsInt(IV, getContext())) { |
| assert(IV.getBitWidth() == getContext().getTypeSize(OOE->getType())); |
| assert(OOE->getType()->isIntegerType()); |
| assert(IV.isSigned() == OOE->getType()->isSignedIntegerOrEnumerationType()); |
| SVal X = svalBuilder.makeIntVal(IV); |
| B.generateNode(OOE, Pred, |
| Pred->getState()->BindExpr(OOE, Pred->getLocationContext(), |
| X)); |
| } |
| // FIXME: Handle the case where __builtin_offsetof is not a constant. |
| } |
| |
| |
| void ExprEngine:: |
| VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex, |
| ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| StmtNodeBuilder Bldr(Pred, Dst, *currentBuilderContext); |
| |
| QualType T = Ex->getTypeOfArgument(); |
| |
| if (Ex->getKind() == UETT_SizeOf) { |
| if (!T->isIncompleteType() && !T->isConstantSizeType()) { |
| assert(T->isVariableArrayType() && "Unknown non-constant-sized type."); |
| |
| // FIXME: Add support for VLA type arguments and VLA expressions. |
| // When that happens, we should probably refactor VLASizeChecker's code. |
| return; |
| } |
| else if (T->getAs<ObjCObjectType>()) { |
| // Some code tries to take the sizeof an ObjCObjectType, relying that |
| // the compiler has laid out its representation. Just report Unknown |
| // for these. |
| return; |
| } |
| } |
| |
| APSInt Value = Ex->EvaluateKnownConstInt(getContext()); |
| CharUnits amt = CharUnits::fromQuantity(Value.getZExtValue()); |
| |
| ProgramStateRef state = Pred->getState(); |
| state = state->BindExpr(Ex, Pred->getLocationContext(), |
| svalBuilder.makeIntVal(amt.getQuantity(), |
| Ex->getType())); |
| Bldr.generateNode(Ex, Pred, state); |
| } |
| |
| void ExprEngine::VisitUnaryOperator(const UnaryOperator* U, |
| ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| StmtNodeBuilder Bldr(Pred, Dst, *currentBuilderContext); |
| switch (U->getOpcode()) { |
| default: { |
| Bldr.takeNodes(Pred); |
| ExplodedNodeSet Tmp; |
| VisitIncrementDecrementOperator(U, Pred, Tmp); |
| Bldr.addNodes(Tmp); |
| } |
| break; |
| case UO_Real: { |
| const Expr *Ex = U->getSubExpr()->IgnoreParens(); |
| |
| // FIXME: We don't have complex SValues yet. |
| if (Ex->getType()->isAnyComplexType()) { |
| // Just report "Unknown." |
| break; |
| } |
| |
| // For all other types, UO_Real is an identity operation. |
| assert (U->getType() == Ex->getType()); |
| ProgramStateRef state = Pred->getState(); |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| Bldr.generateNode(U, Pred, state->BindExpr(U, LCtx, |
| state->getSVal(Ex, LCtx))); |
| break; |
| } |
| |
| case UO_Imag: { |
| const Expr *Ex = U->getSubExpr()->IgnoreParens(); |
| // FIXME: We don't have complex SValues yet. |
| if (Ex->getType()->isAnyComplexType()) { |
| // Just report "Unknown." |
| break; |
| } |
| // For all other types, UO_Imag returns 0. |
| ProgramStateRef state = Pred->getState(); |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| SVal X = svalBuilder.makeZeroVal(Ex->getType()); |
| Bldr.generateNode(U, Pred, state->BindExpr(U, LCtx, X)); |
| break; |
| } |
| |
| case UO_Plus: |
| assert(!U->isLValue()); |
| // FALL-THROUGH. |
| case UO_Deref: |
| case UO_AddrOf: |
| case UO_Extension: { |
| |
| // Unary "+" is a no-op, similar to a parentheses. We still have places |
| // where it may be a block-level expression, so we need to |
| // generate an extra node that just propagates the value of the |
| // subexpression. |
| |
| const Expr *Ex = U->getSubExpr()->IgnoreParens(); |
| ExplodedNodeSet Tmp; |
| Visit(Ex, Pred, Tmp); |
| |
| for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) { |
| ProgramStateRef state = (*I)->getState(); |
| const LocationContext *LCtx = (*I)->getLocationContext(); |
| Bldr.generateNode(U, *I, state->BindExpr(U, LCtx, |
| state->getSVal(Ex, LCtx))); |
| } |
| |
| break; |
| } |
| |
| case UO_LNot: |
| case UO_Minus: |
| case UO_Not: { |
| assert (!U->isLValue()); |
| const Expr *Ex = U->getSubExpr()->IgnoreParens(); |
| ExplodedNodeSet Tmp; |
| Visit(Ex, Pred, Tmp); |
| |
| for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) { |
| ProgramStateRef state = (*I)->getState(); |
| const LocationContext *LCtx = (*I)->getLocationContext(); |
| |
| // Get the value of the subexpression. |
| SVal V = state->getSVal(Ex, LCtx); |
| |
| if (V.isUnknownOrUndef()) { |
| Bldr.generateNode(U, *I, state->BindExpr(U, LCtx, V)); |
| continue; |
| } |
| |
| switch (U->getOpcode()) { |
| default: |
| llvm_unreachable("Invalid Opcode."); |
| |
| case UO_Not: |
| // FIXME: Do we need to handle promotions? |
| state = state->BindExpr(U, LCtx, evalComplement(cast<NonLoc>(V))); |
| break; |
| |
| case UO_Minus: |
| // FIXME: Do we need to handle promotions? |
| state = state->BindExpr(U, LCtx, evalMinus(cast<NonLoc>(V))); |
| break; |
| |
| case UO_LNot: |
| |
| // C99 6.5.3.3: "The expression !E is equivalent to (0==E)." |
| // |
| // Note: technically we do "E == 0", but this is the same in the |
| // transfer functions as "0 == E". |
| SVal Result; |
| |
| if (isa<Loc>(V)) { |
| Loc X = svalBuilder.makeNull(); |
| Result = evalBinOp(state, BO_EQ, cast<Loc>(V), X, |
| U->getType()); |
| } |
| else { |
| nonloc::ConcreteInt X(getBasicVals().getValue(0, Ex->getType())); |
| Result = evalBinOp(state, BO_EQ, cast<NonLoc>(V), X, |
| U->getType()); |
| } |
| |
| state = state->BindExpr(U, LCtx, Result); |
| |
| break; |
| } |
| Bldr.generateNode(U, *I, state); |
| } |
| break; |
| } |
| } |
| |
| } |
| |
| void ExprEngine::VisitIncrementDecrementOperator(const UnaryOperator* U, |
| ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| // Handle ++ and -- (both pre- and post-increment). |
| assert (U->isIncrementDecrementOp()); |
| ExplodedNodeSet Tmp; |
| const Expr *Ex = U->getSubExpr()->IgnoreParens(); |
| Visit(Ex, Pred, Tmp); |
| |
| for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end(); I!=E; ++I) { |
| const LocationContext *LCtx = (*I)->getLocationContext(); |
| ProgramStateRef state = (*I)->getState(); |
| SVal loc = state->getSVal(Ex, LCtx); |
| |
| // Perform a load. |
| ExplodedNodeSet Tmp2; |
| evalLoad(Tmp2, Ex, *I, state, loc); |
| |
| ExplodedNodeSet Dst2; |
| StmtNodeBuilder Bldr(Tmp2, Dst2, *currentBuilderContext); |
| for (ExplodedNodeSet::iterator I2=Tmp2.begin(), E2=Tmp2.end();I2!=E2;++I2) { |
| |
| state = (*I2)->getState(); |
| assert(LCtx == (*I2)->getLocationContext()); |
| SVal V2_untested = state->getSVal(Ex, LCtx); |
| |
| // Propagate unknown and undefined values. |
| if (V2_untested.isUnknownOrUndef()) { |
| Bldr.generateNode(U, *I2, state->BindExpr(U, LCtx, V2_untested)); |
| continue; |
| } |
| DefinedSVal V2 = cast<DefinedSVal>(V2_untested); |
| |
| // Handle all other values. |
| BinaryOperator::Opcode Op = U->isIncrementOp() ? BO_Add |
| : BO_Sub; |
| |
| // If the UnaryOperator has non-location type, use its type to create the |
| // constant value. If the UnaryOperator has location type, create the |
| // constant with int type and pointer width. |
| SVal RHS; |
| |
| if (U->getType()->isAnyPointerType()) |
| RHS = svalBuilder.makeArrayIndex(1); |
| else |
| RHS = svalBuilder.makeIntVal(1, U->getType()); |
| |
| SVal Result = evalBinOp(state, Op, V2, RHS, U->getType()); |
| |
| // Conjure a new symbol if necessary to recover precision. |
| if (Result.isUnknown()){ |
| DefinedOrUnknownSVal SymVal = |
| svalBuilder.getConjuredSymbolVal(NULL, Ex, |
| currentBuilderContext->getCurrentBlockCount()); |
| Result = SymVal; |
| |
| // If the value is a location, ++/-- should always preserve |
| // non-nullness. Check if the original value was non-null, and if so |
| // propagate that constraint. |
| if (Loc::isLocType(U->getType())) { |
| DefinedOrUnknownSVal Constraint = |
| svalBuilder.evalEQ(state, V2,svalBuilder.makeZeroVal(U->getType())); |
| |
| if (!state->assume(Constraint, true)) { |
| // It isn't feasible for the original value to be null. |
| // Propagate this constraint. |
| Constraint = svalBuilder.evalEQ(state, SymVal, |
| svalBuilder.makeZeroVal(U->getType())); |
| |
| |
| state = state->assume(Constraint, false); |
| assert(state); |
| } |
| } |
| } |
| |
| // Since the lvalue-to-rvalue conversion is explicit in the AST, |
| // we bind an l-value if the operator is prefix and an lvalue (in C++). |
| if (U->isLValue()) |
| state = state->BindExpr(U, LCtx, loc); |
| else |
| state = state->BindExpr(U, LCtx, U->isPostfix() ? V2 : Result); |
| |
| // Perform the store. |
| Bldr.takeNodes(*I2); |
| ExplodedNodeSet Dst4; |
| evalStore(Dst4, NULL, U, *I2, state, loc, Result); |
| Bldr.addNodes(Dst4); |
| } |
| Dst.insert(Dst2); |
| } |
| } |
