lib/StaticAnalyzer/Core/SimpleConstraintManager.cpp - third_party/swift-clang - Git at Google

 //== SimpleConstraintManager.cpp --------------------------------*- 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 SimpleConstraintManager, a class that holds code shared
 //  between BasicConstraintManager and RangeConstraintManager.
 //
 //===----------------------------------------------------------------------===//

 #include "SimpleConstraintManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"

 namespace clang {

 namespace ento {

 SimpleConstraintManager::~SimpleConstraintManager() {}

 bool SimpleConstraintManager::canReasonAbout(SVal X) const {
   Optional<nonloc::SymbolVal> SymVal = X.getAs<nonloc::SymbolVal>();
   if (SymVal && SymVal->isExpression()) {
     const SymExpr *SE = SymVal->getSymbol();

     if (const SymIntExpr *SIE = dyn_cast<SymIntExpr>(SE)) {
       switch (SIE->getOpcode()) {
           // We don't reason yet about bitwise-constraints on symbolic values.
         case BO_And:
         case BO_Or:
         case BO_Xor:
           return false;
         // We don't reason yet about these arithmetic constraints on
         // symbolic values.
         case BO_Mul:
         case BO_Div:
         case BO_Rem:
         case BO_Shl:
         case BO_Shr:
           return false;
         // All other cases.
         default:
           return true;
       }
     }

     if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(SE)) {
       if (BinaryOperator::isComparisonOp(SSE->getOpcode())) {
         // We handle Loc <> Loc comparisons, but not (yet) NonLoc <> NonLoc.
         if (Loc::isLocType(SSE->getLHS()->getType())) {
           assert(Loc::isLocType(SSE->getRHS()->getType()));
           return true;
         }
       }
     }

     return false;
   }

   return true;
 }

 ProgramStateRef SimpleConstraintManager::assume(ProgramStateRef state,
                                                DefinedSVal Cond,
                                                bool Assumption) {
   // If we have a Loc value, cast it to a bool NonLoc first.
   if (Optional<Loc> LV = Cond.getAs<Loc>()) {
     SValBuilder &SVB = state->getStateManager().getSValBuilder();
     QualType T;
     const MemRegion *MR = LV->getAsRegion();
     if (const TypedRegion *TR = dyn_cast_or_null<TypedRegion>(MR))
       T = TR->getLocationType();
     else
       T = SVB.getContext().VoidPtrTy;

     Cond = SVB.evalCast(*LV, SVB.getContext().BoolTy, T).castAs<DefinedSVal>();
   }

   return assume(state, Cond.castAs<NonLoc>(), Assumption);
 }

 ProgramStateRef SimpleConstraintManager::assume(ProgramStateRef state,
                                                NonLoc cond,
                                                bool assumption) {
   state = assumeAux(state, cond, assumption);
   if (NotifyAssumeClients && SU)
     return SU->processAssume(state, cond, assumption);
   return state;
 }


 ProgramStateRef
 SimpleConstraintManager::assumeAuxForSymbol(ProgramStateRef State,
                                             SymbolRef Sym, bool Assumption) {
   BasicValueFactory &BVF = getBasicVals();
   QualType T = Sym->getType();

   // None of the constraint solvers currently support non-integer types.
   if (!T->isIntegralOrEnumerationType())
     return State;

   const llvm::APSInt &zero = BVF.getValue(0, T);
   if (Assumption)
     return assumeSymNE(State, Sym, zero, zero);
   else
     return assumeSymEQ(State, Sym, zero, zero);
 }

 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::LocAsIntegerKind:
     return assume(state, Cond.castAs<nonloc::LocAsInteger>().getLoc(),
                   Assumption);
   } // end switch
 }

 ProgramStateRef SimpleConstraintManager::assumeWithinInclusiveRange(
     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("'assumeWithinInclusiveRange' 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
 }

 static void computeAdjustment(SymbolRef &Sym, llvm::APSInt &Adjustment) {
   // Is it a "($sym+constant1)" expression?
   if (const SymIntExpr *SE = dyn_cast<SymIntExpr>(Sym)) {
     BinaryOperator::Opcode Op = SE->getOpcode();
     if (Op == BO_Add || Op == BO_Sub) {
       Sym = SE->getLHS();
       Adjustment = APSIntType(Adjustment).convert(SE->getRHS());

       // Don't forget to negate the adjustment if it's being subtracted.
       // This should happen /after/ promotion, in case the value being
       // subtracted is, say, CHAR_MIN, and the promoted type is 'int'.
       if (Op == BO_Sub)
         Adjustment = -Adjustment;
     }
   }
 }

 ProgramStateRef SimpleConstraintManager::assumeSymRel(ProgramStateRef state,
                                                      const SymExpr *LHS,
                                                      BinaryOperator::Opcode op,
                                                      const llvm::APSInt& Int) {
   assert(BinaryOperator::isComparisonOp(op) &&
          "Non-comparison ops should be rewritten as comparisons to zero.");

   // Get the type used for calculating wraparound.
   BasicValueFactory &BVF = getBasicVals();
   APSIntType WraparoundType = BVF.getAPSIntType(LHS->getType());

   // We only handle simple comparisons of the form "$sym == constant"
   // or "($sym+constant1) == constant2".
   // The adjustment is "constant1" in the above expression. It's used to
   // "slide" the solution range around for modular arithmetic. For example,
   // x < 4 has the solution [0, 3]. x+2 < 4 has the solution [0-2, 3-2], which
   // in modular arithmetic is [0, 1] U [UINT_MAX-1, UINT_MAX]. It's up to
   // the subclasses of SimpleConstraintManager to handle the adjustment.
   SymbolRef Sym = LHS;
   llvm::APSInt Adjustment = WraparoundType.getZeroValue();
   computeAdjustment(Sym, Adjustment);

   // Convert the right-hand side integer as necessary.
   APSIntType ComparisonType = std::max(WraparoundType, APSIntType(Int));
   llvm::APSInt ConvertedInt = ComparisonType.convert(Int);

   // Prefer unsigned comparisons.
   if (ComparisonType.getBitWidth() == WraparoundType.getBitWidth() &&
       ComparisonType.isUnsigned() && !WraparoundType.isUnsigned())
     Adjustment.setIsSigned(false);

   switch (op) {
   default:
     llvm_unreachable("invalid operation not caught by assertion above");

   case BO_EQ:
     return assumeSymEQ(state, Sym, ConvertedInt, Adjustment);

   case BO_NE:
     return assumeSymNE(state, Sym, ConvertedInt, Adjustment);

   case BO_GT:
     return assumeSymGT(state, Sym, ConvertedInt, Adjustment);

   case BO_GE:
     return assumeSymGE(state, Sym, ConvertedInt, Adjustment);

   case BO_LT:
     return assumeSymLT(state, Sym, ConvertedInt, Adjustment);

   case BO_LE:
     return assumeSymLE(state, Sym, ConvertedInt, Adjustment);
   } // end switch
 }

 ProgramStateRef
 SimpleConstraintManager::assumeSymWithinInclusiveRange(ProgramStateRef State,
                                                        SymbolRef Sym,
                                                        const llvm::APSInt &From,
                                                        const llvm::APSInt &To,
                                                        bool InRange) {
   // Get the type used for calculating wraparound.
   BasicValueFactory &BVF = getBasicVals();
   APSIntType WraparoundType = BVF.getAPSIntType(Sym->getType());

   llvm::APSInt Adjustment = WraparoundType.getZeroValue();
   SymbolRef AdjustedSym = Sym;
   computeAdjustment(AdjustedSym, Adjustment);

   // Convert the right-hand side integer as necessary.
   APSIntType ComparisonType = std::max(WraparoundType, APSIntType(From));
   llvm::APSInt ConvertedFrom = ComparisonType.convert(From);
   llvm::APSInt ConvertedTo = ComparisonType.convert(To);

   // Prefer unsigned comparisons.
   if (ComparisonType.getBitWidth() == WraparoundType.getBitWidth() &&
       ComparisonType.isUnsigned() && !WraparoundType.isUnsigned())
     Adjustment.setIsSigned(false);

   if (InRange)
     return assumeSymbolWithinInclusiveRange(State, AdjustedSym, ConvertedFrom,
                                             ConvertedTo, Adjustment);
   return assumeSymbolOutOfInclusiveRange(State, AdjustedSym, ConvertedFrom,
                                          ConvertedTo, Adjustment);
 }

 } // end of namespace ento

 } // end of namespace clang
	//== SimpleConstraintManager.cpp --------------------------------- 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 SimpleConstraintManager, a class that holds code shared
	// between BasicConstraintManager and RangeConstraintManager.
	//
	//===----------------------------------------------------------------------===//

	#include "SimpleConstraintManager.h"
	#include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
	#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
	#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"

	namespace clang {

	namespace ento {

	SimpleConstraintManager::~SimpleConstraintManager() {}

	bool SimpleConstraintManager::canReasonAbout(SVal X) const {
	Optional<nonloc::SymbolVal> SymVal = X.getAs<nonloc::SymbolVal>();
	if (SymVal && SymVal->isExpression()) {
	const SymExpr *SE = SymVal->getSymbol();

	if (const SymIntExpr *SIE = dyn_cast<SymIntExpr>(SE)) {
	switch (SIE->getOpcode()) {
	// We don't reason yet about bitwise-constraints on symbolic values.
	case BO_And:
	case BO_Or:
	case BO_Xor:
	return false;
	// We don't reason yet about these arithmetic constraints on
	// symbolic values.
	case BO_Mul:
	case BO_Div:
	case BO_Rem:
	case BO_Shl:
	case BO_Shr:
	return false;
	// All other cases.
	default:
	return true;
	}
	}

	if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(SE)) {
	if (BinaryOperator::isComparisonOp(SSE->getOpcode())) {
	// We handle Loc <> Loc comparisons, but not (yet) NonLoc <> NonLoc.
	if (Loc::isLocType(SSE->getLHS()->getType())) {
	assert(Loc::isLocType(SSE->getRHS()->getType()));
	return true;
	}
	}
	}

	return false;
	}

	return true;
	}

	ProgramStateRef SimpleConstraintManager::assume(ProgramStateRef state,
	DefinedSVal Cond,
	bool Assumption) {
	// If we have a Loc value, cast it to a bool NonLoc first.
	if (Optional<Loc> LV = Cond.getAs<Loc>()) {
	SValBuilder &SVB = state->getStateManager().getSValBuilder();
	QualType T;
	const MemRegion *MR = LV->getAsRegion();
	if (const TypedRegion *TR = dyn_cast_or_null<TypedRegion>(MR))
	T = TR->getLocationType();
	else
	T = SVB.getContext().VoidPtrTy;

	Cond = SVB.evalCast(*LV, SVB.getContext().BoolTy, T).castAs<DefinedSVal>();
	}

	return assume(state, Cond.castAs<NonLoc>(), Assumption);
	}

	ProgramStateRef SimpleConstraintManager::assume(ProgramStateRef state,
	NonLoc cond,
	bool assumption) {
	state = assumeAux(state, cond, assumption);
	if (NotifyAssumeClients && SU)
	return SU->processAssume(state, cond, assumption);
	return state;
	}


	ProgramStateRef
	SimpleConstraintManager::assumeAuxForSymbol(ProgramStateRef State,
	SymbolRef Sym, bool Assumption) {
	BasicValueFactory &BVF = getBasicVals();
	QualType T = Sym->getType();

	// None of the constraint solvers currently support non-integer types.
	if (!T->isIntegralOrEnumerationType())
	return State;

	const llvm::APSInt &zero = BVF.getValue(0, T);
	if (Assumption)
	return assumeSymNE(State, Sym, zero, zero);
	else
	return assumeSymEQ(State, Sym, zero, zero);
	}

	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::LocAsIntegerKind:
	return assume(state, Cond.castAs<nonloc::LocAsInteger>().getLoc(),
	Assumption);
	} // end switch
	}

	ProgramStateRef SimpleConstraintManager::assumeWithinInclusiveRange(
	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("'assumeWithinInclusiveRange' 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
	}

	static void computeAdjustment(SymbolRef &Sym, llvm::APSInt &Adjustment) {
	// Is it a "($sym+constant1)" expression?
	if (const SymIntExpr *SE = dyn_cast<SymIntExpr>(Sym)) {
	BinaryOperator::Opcode Op = SE->getOpcode();
	if (Op == BO_Add \|\| Op == BO_Sub) {
	Sym = SE->getLHS();
	Adjustment = APSIntType(Adjustment).convert(SE->getRHS());

	// Don't forget to negate the adjustment if it's being subtracted.
	// This should happen /after/ promotion, in case the value being
	// subtracted is, say, CHAR_MIN, and the promoted type is 'int'.
	if (Op == BO_Sub)
	Adjustment = -Adjustment;
	}
	}
	}

	ProgramStateRef SimpleConstraintManager::assumeSymRel(ProgramStateRef state,
	const SymExpr *LHS,
	BinaryOperator::Opcode op,
	const llvm::APSInt& Int) {
	assert(BinaryOperator::isComparisonOp(op) &&
	"Non-comparison ops should be rewritten as comparisons to zero.");

	// Get the type used for calculating wraparound.
	BasicValueFactory &BVF = getBasicVals();
	APSIntType WraparoundType = BVF.getAPSIntType(LHS->getType());

	// We only handle simple comparisons of the form "$sym == constant"
	// or "($sym+constant1) == constant2".
	// The adjustment is "constant1" in the above expression. It's used to
	// "slide" the solution range around for modular arithmetic. For example,
	// x < 4 has the solution [0, 3]. x+2 < 4 has the solution [0-2, 3-2], which
	// in modular arithmetic is [0, 1] U [UINT_MAX-1, UINT_MAX]. It's up to
	// the subclasses of SimpleConstraintManager to handle the adjustment.
	SymbolRef Sym = LHS;
	llvm::APSInt Adjustment = WraparoundType.getZeroValue();
	computeAdjustment(Sym, Adjustment);

	// Convert the right-hand side integer as necessary.
	APSIntType ComparisonType = std::max(WraparoundType, APSIntType(Int));
	llvm::APSInt ConvertedInt = ComparisonType.convert(Int);

	// Prefer unsigned comparisons.
	if (ComparisonType.getBitWidth() == WraparoundType.getBitWidth() &&
	ComparisonType.isUnsigned() && !WraparoundType.isUnsigned())
	Adjustment.setIsSigned(false);

	switch (op) {
	default:
	llvm_unreachable("invalid operation not caught by assertion above");

	case BO_EQ:
	return assumeSymEQ(state, Sym, ConvertedInt, Adjustment);

	case BO_NE:
	return assumeSymNE(state, Sym, ConvertedInt, Adjustment);

	case BO_GT:
	return assumeSymGT(state, Sym, ConvertedInt, Adjustment);

	case BO_GE:
	return assumeSymGE(state, Sym, ConvertedInt, Adjustment);

	case BO_LT:
	return assumeSymLT(state, Sym, ConvertedInt, Adjustment);

	case BO_LE:
	return assumeSymLE(state, Sym, ConvertedInt, Adjustment);
	} // end switch
	}

	ProgramStateRef
	SimpleConstraintManager::assumeSymWithinInclusiveRange(ProgramStateRef State,
	SymbolRef Sym,
	const llvm::APSInt &From,
	const llvm::APSInt &To,
	bool InRange) {
	// Get the type used for calculating wraparound.
	BasicValueFactory &BVF = getBasicVals();
	APSIntType WraparoundType = BVF.getAPSIntType(Sym->getType());

	llvm::APSInt Adjustment = WraparoundType.getZeroValue();
	SymbolRef AdjustedSym = Sym;
	computeAdjustment(AdjustedSym, Adjustment);

	// Convert the right-hand side integer as necessary.
	APSIntType ComparisonType = std::max(WraparoundType, APSIntType(From));
	llvm::APSInt ConvertedFrom = ComparisonType.convert(From);
	llvm::APSInt ConvertedTo = ComparisonType.convert(To);

	// Prefer unsigned comparisons.
	if (ComparisonType.getBitWidth() == WraparoundType.getBitWidth() &&
	ComparisonType.isUnsigned() && !WraparoundType.isUnsigned())
	Adjustment.setIsSigned(false);

	if (InRange)
	return assumeSymbolWithinInclusiveRange(State, AdjustedSym, ConvertedFrom,
	ConvertedTo, Adjustment);
	return assumeSymbolOutOfInclusiveRange(State, AdjustedSym, ConvertedFrom,
	ConvertedTo, Adjustment);
	}

	} // end of namespace ento

	} // end of namespace clang