ProgramStateRef SimpleConstraintManager::assumeInclusiveRange( ProgramStateRef State, NonLoc Value, const llvm::APSInt &From, const llvm::APSInt &To, bool InRange) { assert(From.isUnsigned() == To.isUnsigned() && From.getBitWidth() == To.getBitWidth() && "Values should have same types!"); if (!canReasonAbout(Value)) { // Just add the constraint to the expression without trying to simplify. SymbolRef Sym = Value.getAsSymExpr(); assert(Sym); return assumeSymWithinInclusiveRange(State, Sym, From, To, InRange); } switch (Value.getSubKind()) { default: llvm_unreachable("'assumeInclusiveRange' is not implemented" "for this NonLoc"); case nonloc::LocAsIntegerKind: case nonloc::SymbolValKind: { if (SymbolRef Sym = Value.getAsSymbol()) return assumeSymWithinInclusiveRange(State, Sym, From, To, InRange); return State; } // end switch case nonloc::ConcreteIntKind: { const llvm::APSInt &IntVal = Value.castAs<nonloc::ConcreteInt>().getValue(); bool IsInRange = IntVal >= From && IntVal <= To; bool isFeasible = (IsInRange == InRange); return isFeasible ? State : nullptr; } } // end switch }
const GRState *SimpleConstraintManager::AssumeAux(const GRState *state, NonLoc Cond, bool Assumption) { // We cannot reason about SymIntExpr and SymSymExpr. if (!canReasonAbout(Cond)) { // Just return the current state indicating that the path is feasible. // This may be an over-approximation of what is possible. return state; } BasicValueFactory &BasicVals = state->getBasicVals(); SymbolManager &SymMgr = state->getSymbolManager(); switch (Cond.getSubKind()) { default: assert(false && "'Assume' not implemented for this NonLoc"); case nonloc::SymbolValKind: { nonloc::SymbolVal& SV = cast<nonloc::SymbolVal>(Cond); SymbolRef sym = SV.getSymbol(); QualType T = SymMgr.getType(sym); const llvm::APSInt &zero = BasicVals.getValue(0, T); return Assumption ? AssumeSymNE(state, sym, zero) : AssumeSymEQ(state, sym, zero); } case nonloc::SymExprValKind: { nonloc::SymExprVal V = cast<nonloc::SymExprVal>(Cond); if (const SymIntExpr *SE = dyn_cast<SymIntExpr>(V.getSymbolicExpression())){ // FIXME: This is a hack. It silently converts the RHS integer to be // of the same type as on the left side. This should be removed once // we support truncation/extension of symbolic values. GRStateManager &StateMgr = state->getStateManager(); ASTContext &Ctx = StateMgr.getContext(); QualType LHSType = SE->getLHS()->getType(Ctx); BasicValueFactory &BasicVals = StateMgr.getBasicVals(); const llvm::APSInt &RHS = BasicVals.Convert(LHSType, SE->getRHS()); SymIntExpr SENew(SE->getLHS(), SE->getOpcode(), RHS, SE->getType(Ctx)); return AssumeSymInt(state, Assumption, &SENew); } // For all other symbolic expressions, over-approximate and consider // the constraint feasible. return state; } case nonloc::ConcreteIntKind: { bool b = cast<nonloc::ConcreteInt>(Cond).getValue() != 0; bool isFeasible = b ? Assumption : !Assumption; return isFeasible ? state : NULL; } case nonloc::LocAsIntegerKind: return AssumeAux(state, cast<nonloc::LocAsInteger>(Cond).getLoc(), Assumption); } // end switch }
const GRState* SimpleConstraintManager::AssumeAux(const GRState* St,NonLoc Cond, bool Assumption, bool& isFeasible) { // We cannot reason about SymIntExpr and SymSymExpr. if (!canReasonAbout(Cond)) { isFeasible = true; return St; } BasicValueFactory& BasicVals = StateMgr.getBasicVals(); SymbolManager& SymMgr = StateMgr.getSymbolManager(); switch (Cond.getSubKind()) { default: assert(false && "'Assume' not implemented for this NonLoc"); case nonloc::SymbolValKind: { nonloc::SymbolVal& SV = cast<nonloc::SymbolVal>(Cond); SymbolRef sym = SV.getSymbol(); QualType T = SymMgr.getType(sym); if (Assumption) return AssumeSymNE(St, sym, BasicVals.getValue(0, T), isFeasible); else return AssumeSymEQ(St, sym, BasicVals.getValue(0, T), isFeasible); } case nonloc::SymExprValKind: { nonloc::SymExprVal V = cast<nonloc::SymExprVal>(Cond); if (const SymIntExpr *SE = dyn_cast<SymIntExpr>(V.getSymbolicExpression())) return AssumeSymInt(St, Assumption, SE, isFeasible); isFeasible = true; return St; } case nonloc::ConcreteIntKind: { bool b = cast<nonloc::ConcreteInt>(Cond).getValue() != 0; isFeasible = b ? Assumption : !Assumption; return St; } case nonloc::LocAsIntegerKind: return AssumeAux(St, cast<nonloc::LocAsInteger>(Cond).getLoc(), Assumption, isFeasible); } // end switch }
ProgramStateRef SimpleConstraintManager::assumeAux(ProgramStateRef State, NonLoc Cond, bool Assumption) { // We cannot reason about SymSymExprs, and can only reason about some // SymIntExprs. if (!canReasonAbout(Cond)) { // Just add the constraint to the expression without trying to simplify. SymbolRef Sym = Cond.getAsSymExpr(); return assumeAuxForSymbol(State, Sym, Assumption); } switch (Cond.getSubKind()) { default: llvm_unreachable("'Assume' not implemented for this NonLoc"); case nonloc::SymbolValKind: { nonloc::SymbolVal SV = Cond.castAs<nonloc::SymbolVal>(); SymbolRef Sym = SV.getSymbol(); assert(Sym); // Handle SymbolData. if (!SV.isExpression()) { return assumeAuxForSymbol(State, Sym, Assumption); // Handle symbolic expression. } else if (const SymIntExpr *SE = dyn_cast<SymIntExpr>(Sym)) { // We can only simplify expressions whose RHS is an integer. BinaryOperator::Opcode Op = SE->getOpcode(); if (BinaryOperator::isComparisonOp(Op)) { if (!Assumption) Op = BinaryOperator::negateComparisonOp(Op); return assumeSymRel(State, SE->getLHS(), Op, SE->getRHS()); } } else if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(Sym)) { // Translate "a != b" to "(b - a) != 0". // We invert the order of the operands as a heuristic for how loop // conditions are usually written ("begin != end") as compared to length // calculations ("end - begin"). The more correct thing to do would be to // canonicalize "a - b" and "b - a", which would allow us to treat // "a != b" and "b != a" the same. SymbolManager &SymMgr = getSymbolManager(); BinaryOperator::Opcode Op = SSE->getOpcode(); assert(BinaryOperator::isComparisonOp(Op)); // For now, we only support comparing pointers. assert(Loc::isLocType(SSE->getLHS()->getType())); assert(Loc::isLocType(SSE->getRHS()->getType())); QualType DiffTy = SymMgr.getContext().getPointerDiffType(); SymbolRef Subtraction = SymMgr.getSymSymExpr(SSE->getRHS(), BO_Sub, SSE->getLHS(), DiffTy); const llvm::APSInt &Zero = getBasicVals().getValue(0, DiffTy); Op = BinaryOperator::reverseComparisonOp(Op); if (!Assumption) Op = BinaryOperator::negateComparisonOp(Op); return assumeSymRel(State, Subtraction, Op, Zero); } // If we get here, there's nothing else we can do but treat the symbol as // opaque. return assumeAuxForSymbol(State, Sym, Assumption); } case nonloc::ConcreteIntKind: { bool b = Cond.castAs<nonloc::ConcreteInt>().getValue() != 0; bool isFeasible = b ? Assumption : !Assumption; return isFeasible ? State : nullptr; } case nonloc::PointerToMemberKind: { bool IsNull = !Cond.castAs<nonloc::PointerToMember>().isNullMemberPointer(); bool IsFeasible = IsNull ? Assumption : !Assumption; return IsFeasible ? State : nullptr; } case nonloc::LocAsIntegerKind: return assume(State, Cond.castAs<nonloc::LocAsInteger>().getLoc(), Assumption); } // end switch }
const GRState *SimpleConstraintManager::AssumeAux(const GRState *state, NonLoc Cond, bool Assumption) { // We cannot reason about SymSymExprs, // and can only reason about some SymIntExprs. if (!canReasonAbout(Cond)) { // Just return the current state indicating that the path is feasible. // This may be an over-approximation of what is possible. return state; } BasicValueFactory &BasicVals = state->getBasicVals(); SymbolManager &SymMgr = state->getSymbolManager(); switch (Cond.getSubKind()) { default: assert(false && "'Assume' not implemented for this NonLoc"); case nonloc::SymbolValKind: { nonloc::SymbolVal& SV = cast<nonloc::SymbolVal>(Cond); SymbolRef sym = SV.getSymbol(); QualType T = SymMgr.getType(sym); const llvm::APSInt &zero = BasicVals.getValue(0, T); if (Assumption) return AssumeSymNE(state, sym, zero, zero); else return AssumeSymEQ(state, sym, zero, zero); } case nonloc::SymExprValKind: { nonloc::SymExprVal V = cast<nonloc::SymExprVal>(Cond); // For now, we only handle expressions whose RHS is an integer. // All other expressions are assumed to be feasible. const SymIntExpr *SE = dyn_cast<SymIntExpr>(V.getSymbolicExpression()); if (!SE) return state; BinaryOperator::Opcode op = SE->getOpcode(); // Implicitly compare non-comparison expressions to 0. if (!BinaryOperator::isComparisonOp(op)) { QualType T = SymMgr.getType(SE); const llvm::APSInt &zero = BasicVals.getValue(0, T); op = (Assumption ? BO_NE : BO_EQ); return AssumeSymRel(state, SE, op, zero); } // From here on out, op is the real comparison we'll be testing. if (!Assumption) op = NegateComparison(op); return AssumeSymRel(state, SE->getLHS(), op, SE->getRHS()); } case nonloc::ConcreteIntKind: { bool b = cast<nonloc::ConcreteInt>(Cond).getValue() != 0; bool isFeasible = b ? Assumption : !Assumption; return isFeasible ? state : NULL; } case nonloc::LocAsIntegerKind: return AssumeAux(state, cast<nonloc::LocAsInteger>(Cond).getLoc(), Assumption); } // end switch }
ProgramStateRef SimpleConstraintManager::assumeAux(ProgramStateRef state, NonLoc Cond, bool Assumption) { // We cannot reason about SymSymExprs, and can only reason about some // SymIntExprs. if (!canReasonAbout(Cond)) { // Just add the constraint to the expression without trying to simplify. SymbolRef sym = Cond.getAsSymExpr(); return assumeAuxForSymbol(state, sym, Assumption); } BasicValueFactory &BasicVals = getBasicVals(); switch (Cond.getSubKind()) { default: llvm_unreachable("'Assume' not implemented for this NonLoc"); case nonloc::SymbolValKind: { nonloc::SymbolVal& SV = cast<nonloc::SymbolVal>(Cond); SymbolRef sym = SV.getSymbol(); assert(sym); // Handle SymbolData. if (!SV.isExpression()) { return assumeAuxForSymbol(state, sym, Assumption); // Handle symbolic expression. } else { // We can only simplify expressions whose RHS is an integer. const SymIntExpr *SE = dyn_cast<SymIntExpr>(sym); if (!SE) return assumeAuxForSymbol(state, sym, Assumption); BinaryOperator::Opcode op = SE->getOpcode(); // Implicitly compare non-comparison expressions to 0. if (!BinaryOperator::isComparisonOp(op)) { QualType T = SE->getType(BasicVals.getContext()); const llvm::APSInt &zero = BasicVals.getValue(0, T); op = (Assumption ? BO_NE : BO_EQ); return assumeSymRel(state, SE, op, zero); } // From here on out, op is the real comparison we'll be testing. if (!Assumption) op = NegateComparison(op); return assumeSymRel(state, SE->getLHS(), op, SE->getRHS()); } } case nonloc::ConcreteIntKind: { bool b = cast<nonloc::ConcreteInt>(Cond).getValue() != 0; bool isFeasible = b ? Assumption : !Assumption; return isFeasible ? state : NULL; } case nonloc::LocAsIntegerKind: return assumeAux(state, cast<nonloc::LocAsInteger>(Cond).getLoc(), Assumption); } // end switch }