lib/StaticAnalyzer/Core/RangeConstraintManager.cpp - platform/external/clang - Git at Google

 //== RangeConstraintManager.cpp - Manage range constraints.------*- 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 RangeConstraintManager, a class that tracks simple
 //  equality and inequality constraints on symbolic values of ProgramState.
 //
 //===----------------------------------------------------------------------===//

 #include "SimpleConstraintManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/ImmutableSet.h"
 #include "llvm/Support/raw_ostream.h"

 using namespace clang;
 using namespace ento;

 namespace { class ConstraintRange {}; }
 static int ConstraintRangeIndex = 0;

 /// A Range represents the closed range [from, to].  The caller must
 /// guarantee that from <= to.  Note that Range is immutable, so as not
 /// to subvert RangeSet's immutability.
 namespace {
 class Range : public std::pair<const llvm::APSInt*,
                                                 const llvm::APSInt*> {
 public:
   Range(const llvm::APSInt &from, const llvm::APSInt &to)
     : std::pair<const llvm::APSInt*, const llvm::APSInt*>(&from, &to) {
     assert(from <= to);
   }
   bool Includes(const llvm::APSInt &v) const {
     return *first <= v && v <= *second;
   }
   const llvm::APSInt &From() const {
     return *first;
   }
   const llvm::APSInt &To() const {
     return *second;
   }
   const llvm::APSInt *getConcreteValue() const {
     return &From() == &To() ? &From() : NULL;
   }

   void Profile(llvm::FoldingSetNodeID &ID) const {
     ID.AddPointer(&From());
     ID.AddPointer(&To());
   }
 };


 class RangeTrait : public llvm::ImutContainerInfo<Range> {
 public:
   // When comparing if one Range is less than another, we should compare
   // the actual APSInt values instead of their pointers.  This keeps the order
   // consistent (instead of comparing by pointer values) and can potentially
   // be used to speed up some of the operations in RangeSet.
   static inline bool isLess(key_type_ref lhs, key_type_ref rhs) {
     return *lhs.first < *rhs.first || (!(*rhs.first < *lhs.first) &&
                                        *lhs.second < *rhs.second);
   }
 };

 /// RangeSet contains a set of ranges. If the set is empty, then
 ///  there the value of a symbol is overly constrained and there are no
 ///  possible values for that symbol.
 class RangeSet {
   typedef llvm::ImmutableSet<Range, RangeTrait> PrimRangeSet;
   PrimRangeSet ranges; // no need to make const, since it is an
                        // ImmutableSet - this allows default operator=
                        // to work.
 public:
   typedef PrimRangeSet::Factory Factory;
   typedef PrimRangeSet::iterator iterator;

   RangeSet(PrimRangeSet RS) : ranges(RS) {}

   iterator begin() const { return ranges.begin(); }
   iterator end() const { return ranges.end(); }

   bool isEmpty() const { return ranges.isEmpty(); }

   /// Construct a new RangeSet representing '{ [from, to] }'.
   RangeSet(Factory &F, const llvm::APSInt &from, const llvm::APSInt &to)
     : ranges(F.add(F.getEmptySet(), Range(from, to))) {}

   /// Profile - Generates a hash profile of this RangeSet for use
   ///  by FoldingSet.
   void Profile(llvm::FoldingSetNodeID &ID) const { ranges.Profile(ID); }

   /// getConcreteValue - If a symbol is contrained to equal a specific integer
   ///  constant then this method returns that value.  Otherwise, it returns
   ///  NULL.
   const llvm::APSInt* getConcreteValue() const {
     return ranges.isSingleton() ? ranges.begin()->getConcreteValue() : 0;
   }

 private:
   void IntersectInRange(BasicValueFactory &BV, Factory &F,
                         const llvm::APSInt &Lower,
                         const llvm::APSInt &Upper,
                         PrimRangeSet &newRanges,
                         PrimRangeSet::iterator &i,
                         PrimRangeSet::iterator &e) const {
     // There are six cases for each range R in the set:
     //   1. R is entirely before the intersection range.
     //   2. R is entirely after the intersection range.
     //   3. R contains the entire intersection range.
     //   4. R starts before the intersection range and ends in the middle.
     //   5. R starts in the middle of the intersection range and ends after it.
     //   6. R is entirely contained in the intersection range.
     // These correspond to each of the conditions below.
     for (/* i = begin(), e = end() */; i != e; ++i) {
       if (i->To() < Lower) {
         continue;
       }
       if (i->From() > Upper) {
         break;
       }

       if (i->Includes(Lower)) {
         if (i->Includes(Upper)) {
           newRanges = F.add(newRanges, Range(BV.getValue(Lower),
                                              BV.getValue(Upper)));
           break;
         } else
           newRanges = F.add(newRanges, Range(BV.getValue(Lower), i->To()));
       } else {
         if (i->Includes(Upper)) {
           newRanges = F.add(newRanges, Range(i->From(), BV.getValue(Upper)));
           break;
         } else
           newRanges = F.add(newRanges, *i);
       }
     }
   }

 public:
   // Returns a set containing the values in the receiving set, intersected with
   // the closed range [Lower, Upper]. Unlike the Range type, this range uses
   // modular arithmetic, corresponding to the common treatment of C integer
   // overflow. Thus, if the Lower bound is greater than the Upper bound, the
   // range is taken to wrap around. This is equivalent to taking the
   // intersection with the two ranges [Min, Upper] and [Lower, Max],
   // or, alternatively, /removing/ all integers between Upper and Lower.
   RangeSet Intersect(BasicValueFactory &BV, Factory &F,
                      const llvm::APSInt &Lower,
                      const llvm::APSInt &Upper) const {
     PrimRangeSet newRanges = F.getEmptySet();

     PrimRangeSet::iterator i = begin(), e = end();
     if (Lower <= Upper)
       IntersectInRange(BV, F, Lower, Upper, newRanges, i, e);
     else {
       // The order of the next two statements is important!
       // IntersectInRange() does not reset the iteration state for i and e.
       // Therefore, the lower range most be handled first.
       IntersectInRange(BV, F, BV.getMinValue(Upper), Upper, newRanges, i, e);
       IntersectInRange(BV, F, Lower, BV.getMaxValue(Lower), newRanges, i, e);
     }
     return newRanges;
   }

   void print(raw_ostream &os) const {
     bool isFirst = true;
     os << "{ ";
     for (iterator i = begin(), e = end(); i != e; ++i) {
       if (isFirst)
         isFirst = false;
       else
         os << ", ";

       os << '[' << i->From().toString(10) << ", " << i->To().toString(10)
          << ']';
     }
     os << " }";
   }

   bool operator==(const RangeSet &other) const {
     return ranges == other.ranges;
   }
 };
 } // end anonymous namespace

 typedef llvm::ImmutableMap<SymbolRef,RangeSet> ConstraintRangeTy;

 namespace clang {
 namespace ento {
 template<>
 struct ProgramStateTrait<ConstraintRange>
   : public ProgramStatePartialTrait<ConstraintRangeTy> {
   static inline void *GDMIndex() { return &ConstraintRangeIndex; }
 };
 }
 }

 namespace {
 class RangeConstraintManager : public SimpleConstraintManager{
   RangeSet GetRange(const ProgramState *state, SymbolRef sym);
 public:
   RangeConstraintManager(SubEngine &subengine)
     : SimpleConstraintManager(subengine) {}

   const ProgramState *assumeSymNE(const ProgramState *state, SymbolRef sym,
                              const llvm::APSInt& Int,
                              const llvm::APSInt& Adjustment);

   const ProgramState *assumeSymEQ(const ProgramState *state, SymbolRef sym,
                              const llvm::APSInt& Int,
                              const llvm::APSInt& Adjustment);

   const ProgramState *assumeSymLT(const ProgramState *state, SymbolRef sym,
                              const llvm::APSInt& Int,
                              const llvm::APSInt& Adjustment);

   const ProgramState *assumeSymGT(const ProgramState *state, SymbolRef sym,
                              const llvm::APSInt& Int,
                              const llvm::APSInt& Adjustment);

   const ProgramState *assumeSymGE(const ProgramState *state, SymbolRef sym,
                              const llvm::APSInt& Int,
                              const llvm::APSInt& Adjustment);

   const ProgramState *assumeSymLE(const ProgramState *state, SymbolRef sym,
                              const llvm::APSInt& Int,
                              const llvm::APSInt& Adjustment);

   const llvm::APSInt* getSymVal(const ProgramState *St, SymbolRef sym) const;

   // FIXME: Refactor into SimpleConstraintManager?
   bool isEqual(const ProgramState *St, SymbolRef sym, const llvm::APSInt& V) const {
     const llvm::APSInt *i = getSymVal(St, sym);
     return i ? *i == V : false;
   }

   const ProgramState *removeDeadBindings(const ProgramState *St, SymbolReaper& SymReaper);

   void print(const ProgramState *St, raw_ostream &Out,
              const char* nl, const char *sep);

 private:
   RangeSet::Factory F;
 };

 } // end anonymous namespace

 ConstraintManager* ento::CreateRangeConstraintManager(ProgramStateManager&,
                                                     SubEngine &subeng) {
   return new RangeConstraintManager(subeng);
 }

 const llvm::APSInt* RangeConstraintManager::getSymVal(const ProgramState *St,
                                                       SymbolRef sym) const {
   const ConstraintRangeTy::data_type *T = St->get<ConstraintRange>(sym);
   return T ? T->getConcreteValue() : NULL;
 }

 /// Scan all symbols referenced by the constraints. If the symbol is not alive
 /// as marked in LSymbols, mark it as dead in DSymbols.
 const ProgramState*
 RangeConstraintManager::removeDeadBindings(const ProgramState *state,
                                            SymbolReaper& SymReaper) {

   ConstraintRangeTy CR = state->get<ConstraintRange>();
   ConstraintRangeTy::Factory& CRFactory = state->get_context<ConstraintRange>();

   for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
     SymbolRef sym = I.getKey();
     if (SymReaper.maybeDead(sym))
       CR = CRFactory.remove(CR, sym);
   }

   return state->set<ConstraintRange>(CR);
 }

 RangeSet
 RangeConstraintManager::GetRange(const ProgramState *state, SymbolRef sym) {
   if (ConstraintRangeTy::data_type* V = state->get<ConstraintRange>(sym))
     return *V;

   // Lazily generate a new RangeSet representing all possible values for the
   // given symbol type.
   QualType T = state->getSymbolManager().getType(sym);
   BasicValueFactory& BV = state->getBasicVals();
   return RangeSet(F, BV.getMinValue(T), BV.getMaxValue(T));
 }

 //===------------------------------------------------------------------------===
 // assumeSymX methods: public interface for RangeConstraintManager.
 //===------------------------------------------------------------------------===/

 // The syntax for ranges below is mathematical, using [x, y] for closed ranges
 // and (x, y) for open ranges. These ranges are modular, corresponding with
 // a common treatment of C integer overflow. This means that these methods
 // do not have to worry about overflow; RangeSet::Intersect can handle such a
 // "wraparound" range.
 // As an example, the range [UINT_MAX-1, 3) contains five values: UINT_MAX-1,
 // UINT_MAX, 0, 1, and 2.

 const ProgramState*
 RangeConstraintManager::assumeSymNE(const ProgramState *state, SymbolRef sym,
                                     const llvm::APSInt& Int,
                                     const llvm::APSInt& Adjustment) {
   BasicValueFactory &BV = state->getBasicVals();

   llvm::APSInt Lower = Int-Adjustment;
   llvm::APSInt Upper = Lower;
   --Lower;
   ++Upper;

   // [Int-Adjustment+1, Int-Adjustment-1]
   // Notice that the lower bound is greater than the upper bound.
   RangeSet New = GetRange(state, sym).Intersect(BV, F, Upper, Lower);
   return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
 }

 const ProgramState*
 RangeConstraintManager::assumeSymEQ(const ProgramState *state, SymbolRef sym,
                                     const llvm::APSInt& Int,
                                     const llvm::APSInt& Adjustment) {
   // [Int-Adjustment, Int-Adjustment]
   BasicValueFactory &BV = state->getBasicVals();
   llvm::APSInt AdjInt = Int-Adjustment;
   RangeSet New = GetRange(state, sym).Intersect(BV, F, AdjInt, AdjInt);
   return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
 }

 const ProgramState*
 RangeConstraintManager::assumeSymLT(const ProgramState *state, SymbolRef sym,
                                     const llvm::APSInt& Int,
                                     const llvm::APSInt& Adjustment) {
   BasicValueFactory &BV = state->getBasicVals();

   QualType T = state->getSymbolManager().getType(sym);
   const llvm::APSInt &Min = BV.getMinValue(T);

   // Special case for Int == Min. This is always false.
   if (Int == Min)
     return NULL;

   llvm::APSInt Lower = Min-Adjustment;
   llvm::APSInt Upper = Int-Adjustment;
   --Upper;

   RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
   return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
 }

 const ProgramState*
 RangeConstraintManager::assumeSymGT(const ProgramState *state, SymbolRef sym,
                                     const llvm::APSInt& Int,
                                     const llvm::APSInt& Adjustment) {
   BasicValueFactory &BV = state->getBasicVals();

   QualType T = state->getSymbolManager().getType(sym);
   const llvm::APSInt &Max = BV.getMaxValue(T);

   // Special case for Int == Max. This is always false.
   if (Int == Max)
     return NULL;

   llvm::APSInt Lower = Int-Adjustment;
   llvm::APSInt Upper = Max-Adjustment;
   ++Lower;

   RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
   return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
 }

 const ProgramState*
 RangeConstraintManager::assumeSymGE(const ProgramState *state, SymbolRef sym,
                                     const llvm::APSInt& Int,
                                     const llvm::APSInt& Adjustment) {
   BasicValueFactory &BV = state->getBasicVals();

   QualType T = state->getSymbolManager().getType(sym);
   const llvm::APSInt &Min = BV.getMinValue(T);

   // Special case for Int == Min. This is always feasible.
   if (Int == Min)
     return state;

   const llvm::APSInt &Max = BV.getMaxValue(T);

   llvm::APSInt Lower = Int-Adjustment;
   llvm::APSInt Upper = Max-Adjustment;

   RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
   return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
 }

 const ProgramState*
 RangeConstraintManager::assumeSymLE(const ProgramState *state, SymbolRef sym,
                                     const llvm::APSInt& Int,
                                     const llvm::APSInt& Adjustment) {
   BasicValueFactory &BV = state->getBasicVals();

   QualType T = state->getSymbolManager().getType(sym);
   const llvm::APSInt &Max = BV.getMaxValue(T);

   // Special case for Int == Max. This is always feasible.
   if (Int == Max)
     return state;

   const llvm::APSInt &Min = BV.getMinValue(T);

   llvm::APSInt Lower = Min-Adjustment;
   llvm::APSInt Upper = Int-Adjustment;

   RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
   return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
 }

 //===------------------------------------------------------------------------===
 // Pretty-printing.
 //===------------------------------------------------------------------------===/

 void RangeConstraintManager::print(const ProgramState *St, raw_ostream &Out,
                                    const char* nl, const char *sep) {

   ConstraintRangeTy Ranges = St->get<ConstraintRange>();

   if (Ranges.isEmpty()) {
     Out << nl << sep << "Ranges are empty." << nl;
     return;
   }

   Out << nl << sep << "Ranges of symbol values:";
   for (ConstraintRangeTy::iterator I=Ranges.begin(), E=Ranges.end(); I!=E; ++I){
     Out << nl << ' ' << I.getKey() << " : ";
     I.getData().print(Out);
   }
   Out << nl;
 }
	//== RangeConstraintManager.cpp - Manage range constraints.------- 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 RangeConstraintManager, a class that tracks simple
	// equality and inequality constraints on symbolic values of ProgramState.
	//
	//===----------------------------------------------------------------------===//

	#include "SimpleConstraintManager.h"
	#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
	#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
	#include "llvm/Support/Debug.h"
	#include "llvm/ADT/FoldingSet.h"
	#include "llvm/ADT/ImmutableSet.h"
	#include "llvm/Support/raw_ostream.h"

	using namespace clang;
	using namespace ento;

	namespace { class ConstraintRange {}; }
	static int ConstraintRangeIndex = 0;

	/// A Range represents the closed range [from, to]. The caller must
	/// guarantee that from <= to. Note that Range is immutable, so as not
	/// to subvert RangeSet's immutability.
	namespace {
	class Range : public std::pair<const llvm::APSInt*,
	const llvm::APSInt*> {
	public:
	Range(const llvm::APSInt &from, const llvm::APSInt &to)
	: std::pair<const llvm::APSInt, const llvm::APSInt>(&from, &to) {
	assert(from <= to);
	}
	bool Includes(const llvm::APSInt &v) const {
	return first <= v && v <= second;
	}
	const llvm::APSInt &From() const {
	return *first;
	}
	const llvm::APSInt &To() const {
	return *second;
	}
	const llvm::APSInt *getConcreteValue() const {
	return &From() == &To() ? &From() : NULL;
	}

	void Profile(llvm::FoldingSetNodeID &ID) const {
	ID.AddPointer(&From());
	ID.AddPointer(&To());
	}
	};


	class RangeTrait : public llvm::ImutContainerInfo<Range> {
	public:
	// When comparing if one Range is less than another, we should compare
	// the actual APSInt values instead of their pointers. This keeps the order
	// consistent (instead of comparing by pointer values) and can potentially
	// be used to speed up some of the operations in RangeSet.
	static inline bool isLess(key_type_ref lhs, key_type_ref rhs) {
	return lhs.first < rhs.first \|\| (!(rhs.first < lhs.first) &&
	lhs.second < rhs.second);
	}
	};

	/// RangeSet contains a set of ranges. If the set is empty, then
	/// there the value of a symbol is overly constrained and there are no
	/// possible values for that symbol.
	class RangeSet {
	typedef llvm::ImmutableSet<Range, RangeTrait> PrimRangeSet;
	PrimRangeSet ranges; // no need to make const, since it is an
	// ImmutableSet - this allows default operator=
	// to work.
	public:
	typedef PrimRangeSet::Factory Factory;
	typedef PrimRangeSet::iterator iterator;

	RangeSet(PrimRangeSet RS) : ranges(RS) {}

	iterator begin() const { return ranges.begin(); }
	iterator end() const { return ranges.end(); }

	bool isEmpty() const { return ranges.isEmpty(); }

	/// Construct a new RangeSet representing '{ [from, to] }'.
	RangeSet(Factory &F, const llvm::APSInt &from, const llvm::APSInt &to)
	: ranges(F.add(F.getEmptySet(), Range(from, to))) {}

	/// Profile - Generates a hash profile of this RangeSet for use
	/// by FoldingSet.
	void Profile(llvm::FoldingSetNodeID &ID) const { ranges.Profile(ID); }

	/// getConcreteValue - If a symbol is contrained to equal a specific integer
	/// constant then this method returns that value. Otherwise, it returns
	/// NULL.
	const llvm::APSInt* getConcreteValue() const {
	return ranges.isSingleton() ? ranges.begin()->getConcreteValue() : 0;
	}

	private:
	void IntersectInRange(BasicValueFactory &BV, Factory &F,
	const llvm::APSInt &Lower,
	const llvm::APSInt &Upper,
	PrimRangeSet &newRanges,
	PrimRangeSet::iterator &i,
	PrimRangeSet::iterator &e) const {
	// There are six cases for each range R in the set:
	// 1. R is entirely before the intersection range.
	// 2. R is entirely after the intersection range.
	// 3. R contains the entire intersection range.
	// 4. R starts before the intersection range and ends in the middle.
	// 5. R starts in the middle of the intersection range and ends after it.
	// 6. R is entirely contained in the intersection range.
	// These correspond to each of the conditions below.
	for (/* i = begin(), e = end() */; i != e; ++i) {
	if (i->To() < Lower) {
	continue;
	}
	if (i->From() > Upper) {
	break;
	}

	if (i->Includes(Lower)) {
	if (i->Includes(Upper)) {
	newRanges = F.add(newRanges, Range(BV.getValue(Lower),
	BV.getValue(Upper)));
	break;
	} else
	newRanges = F.add(newRanges, Range(BV.getValue(Lower), i->To()));
	} else {
	if (i->Includes(Upper)) {
	newRanges = F.add(newRanges, Range(i->From(), BV.getValue(Upper)));
	break;
	} else
	newRanges = F.add(newRanges, *i);
	}
	}
	}

	public:
	// Returns a set containing the values in the receiving set, intersected with
	// the closed range [Lower, Upper]. Unlike the Range type, this range uses
	// modular arithmetic, corresponding to the common treatment of C integer
	// overflow. Thus, if the Lower bound is greater than the Upper bound, the
	// range is taken to wrap around. This is equivalent to taking the
	// intersection with the two ranges [Min, Upper] and [Lower, Max],
	// or, alternatively, /removing/ all integers between Upper and Lower.
	RangeSet Intersect(BasicValueFactory &BV, Factory &F,
	const llvm::APSInt &Lower,
	const llvm::APSInt &Upper) const {
	PrimRangeSet newRanges = F.getEmptySet();

	PrimRangeSet::iterator i = begin(), e = end();
	if (Lower <= Upper)
	IntersectInRange(BV, F, Lower, Upper, newRanges, i, e);
	else {
	// The order of the next two statements is important!
	// IntersectInRange() does not reset the iteration state for i and e.
	// Therefore, the lower range most be handled first.
	IntersectInRange(BV, F, BV.getMinValue(Upper), Upper, newRanges, i, e);
	IntersectInRange(BV, F, Lower, BV.getMaxValue(Lower), newRanges, i, e);
	}
	return newRanges;
	}

	void print(raw_ostream &os) const {
	bool isFirst = true;
	os << "{ ";
	for (iterator i = begin(), e = end(); i != e; ++i) {
	if (isFirst)
	isFirst = false;
	else
	os << ", ";

	os << '[' << i->From().toString(10) << ", " << i->To().toString(10)
	<< ']';
	}
	os << " }";
	}

	bool operator==(const RangeSet &other) const {
	return ranges == other.ranges;
	}
	};
	} // end anonymous namespace

	typedef llvm::ImmutableMap<SymbolRef,RangeSet> ConstraintRangeTy;

	namespace clang {
	namespace ento {
	template<>
	struct ProgramStateTrait<ConstraintRange>
	: public ProgramStatePartialTrait<ConstraintRangeTy> {
	static inline void *GDMIndex() { return &ConstraintRangeIndex; }
	};
	}
	}

	namespace {
	class RangeConstraintManager : public SimpleConstraintManager{
	RangeSet GetRange(const ProgramState *state, SymbolRef sym);
	public:
	RangeConstraintManager(SubEngine &subengine)
	: SimpleConstraintManager(subengine) {}

	const ProgramState assumeSymNE(const ProgramState state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment);

	const ProgramState assumeSymEQ(const ProgramState state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment);

	const ProgramState assumeSymLT(const ProgramState state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment);

	const ProgramState assumeSymGT(const ProgramState state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment);

	const ProgramState assumeSymGE(const ProgramState state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment);

	const ProgramState assumeSymLE(const ProgramState state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment);

	const llvm::APSInt* getSymVal(const ProgramState *St, SymbolRef sym) const;

	// FIXME: Refactor into SimpleConstraintManager?
	bool isEqual(const ProgramState *St, SymbolRef sym, const llvm::APSInt& V) const {
	const llvm::APSInt *i = getSymVal(St, sym);
	return i ? *i == V : false;
	}

	const ProgramState removeDeadBindings(const ProgramState St, SymbolReaper& SymReaper);

	void print(const ProgramState *St, raw_ostream &Out,
	const char* nl, const char *sep);

	private:
	RangeSet::Factory F;
	};

	} // end anonymous namespace

	ConstraintManager* ento::CreateRangeConstraintManager(ProgramStateManager&,
	SubEngine &subeng) {
	return new RangeConstraintManager(subeng);
	}

	const llvm::APSInt* RangeConstraintManager::getSymVal(const ProgramState *St,
	SymbolRef sym) const {
	const ConstraintRangeTy::data_type *T = St->get<ConstraintRange>(sym);
	return T ? T->getConcreteValue() : NULL;
	}

	/// Scan all symbols referenced by the constraints. If the symbol is not alive
	/// as marked in LSymbols, mark it as dead in DSymbols.
	const ProgramState*
	RangeConstraintManager::removeDeadBindings(const ProgramState *state,
	SymbolReaper& SymReaper) {

	ConstraintRangeTy CR = state->get<ConstraintRange>();
	ConstraintRangeTy::Factory& CRFactory = state->get_context<ConstraintRange>();

	for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
	SymbolRef sym = I.getKey();
	if (SymReaper.maybeDead(sym))
	CR = CRFactory.remove(CR, sym);
	}

	return state->set<ConstraintRange>(CR);
	}

	RangeSet
	RangeConstraintManager::GetRange(const ProgramState *state, SymbolRef sym) {
	if (ConstraintRangeTy::data_type* V = state->get<ConstraintRange>(sym))
	return *V;

	// Lazily generate a new RangeSet representing all possible values for the
	// given symbol type.
	QualType T = state->getSymbolManager().getType(sym);
	BasicValueFactory& BV = state->getBasicVals();
	return RangeSet(F, BV.getMinValue(T), BV.getMaxValue(T));
	}

	//===------------------------------------------------------------------------===
	// assumeSymX methods: public interface for RangeConstraintManager.
	//===------------------------------------------------------------------------===/

	// The syntax for ranges below is mathematical, using [x, y] for closed ranges
	// and (x, y) for open ranges. These ranges are modular, corresponding with
	// a common treatment of C integer overflow. This means that these methods
	// do not have to worry about overflow; RangeSet::Intersect can handle such a
	// "wraparound" range.
	// As an example, the range [UINT_MAX-1, 3) contains five values: UINT_MAX-1,
	// UINT_MAX, 0, 1, and 2.

	const ProgramState*
	RangeConstraintManager::assumeSymNE(const ProgramState *state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment) {
	BasicValueFactory &BV = state->getBasicVals();

	llvm::APSInt Lower = Int-Adjustment;
	llvm::APSInt Upper = Lower;
	--Lower;
	++Upper;

	// [Int-Adjustment+1, Int-Adjustment-1]
	// Notice that the lower bound is greater than the upper bound.
	RangeSet New = GetRange(state, sym).Intersect(BV, F, Upper, Lower);
	return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
	}

	const ProgramState*
	RangeConstraintManager::assumeSymEQ(const ProgramState *state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment) {
	// [Int-Adjustment, Int-Adjustment]
	BasicValueFactory &BV = state->getBasicVals();
	llvm::APSInt AdjInt = Int-Adjustment;
	RangeSet New = GetRange(state, sym).Intersect(BV, F, AdjInt, AdjInt);
	return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
	}

	const ProgramState*
	RangeConstraintManager::assumeSymLT(const ProgramState *state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment) {
	BasicValueFactory &BV = state->getBasicVals();

	QualType T = state->getSymbolManager().getType(sym);
	const llvm::APSInt &Min = BV.getMinValue(T);

	// Special case for Int == Min. This is always false.
	if (Int == Min)
	return NULL;

	llvm::APSInt Lower = Min-Adjustment;
	llvm::APSInt Upper = Int-Adjustment;
	--Upper;

	RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
	return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
	}

	const ProgramState*
	RangeConstraintManager::assumeSymGT(const ProgramState *state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment) {
	BasicValueFactory &BV = state->getBasicVals();

	QualType T = state->getSymbolManager().getType(sym);
	const llvm::APSInt &Max = BV.getMaxValue(T);

	// Special case for Int == Max. This is always false.
	if (Int == Max)
	return NULL;

	llvm::APSInt Lower = Int-Adjustment;
	llvm::APSInt Upper = Max-Adjustment;
	++Lower;

	RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
	return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
	}

	const ProgramState*
	RangeConstraintManager::assumeSymGE(const ProgramState *state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment) {
	BasicValueFactory &BV = state->getBasicVals();

	QualType T = state->getSymbolManager().getType(sym);
	const llvm::APSInt &Min = BV.getMinValue(T);

	// Special case for Int == Min. This is always feasible.
	if (Int == Min)
	return state;

	const llvm::APSInt &Max = BV.getMaxValue(T);

	llvm::APSInt Lower = Int-Adjustment;
	llvm::APSInt Upper = Max-Adjustment;

	RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
	return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
	}

	const ProgramState*
	RangeConstraintManager::assumeSymLE(const ProgramState *state, SymbolRef sym,
	const llvm::APSInt& Int,
	const llvm::APSInt& Adjustment) {
	BasicValueFactory &BV = state->getBasicVals();

	QualType T = state->getSymbolManager().getType(sym);
	const llvm::APSInt &Max = BV.getMaxValue(T);

	// Special case for Int == Max. This is always feasible.
	if (Int == Max)
	return state;

	const llvm::APSInt &Min = BV.getMinValue(T);

	llvm::APSInt Lower = Min-Adjustment;
	llvm::APSInt Upper = Int-Adjustment;

	RangeSet New = GetRange(state, sym).Intersect(BV, F, Lower, Upper);
	return New.isEmpty() ? NULL : state->set<ConstraintRange>(sym, New);
	}

	//===------------------------------------------------------------------------===
	// Pretty-printing.
	//===------------------------------------------------------------------------===/

	void RangeConstraintManager::print(const ProgramState *St, raw_ostream &Out,
	const char* nl, const char *sep) {

	ConstraintRangeTy Ranges = St->get<ConstraintRange>();

	if (Ranges.isEmpty()) {
	Out << nl << sep << "Ranges are empty." << nl;
	return;
	}

	Out << nl << sep << "Ranges of symbol values:";
	for (ConstraintRangeTy::iterator I=Ranges.begin(), E=Ranges.end(); I!=E; ++I){
	Out << nl << ' ' << I.getKey() << " : ";
	I.getData().print(Out);
	}
	Out << nl;
	}