Patch by Ben Laurie:

ConstraintManager:
- constify getSymVal()

BasicConstraintManager:
- Pull out logic that would be common to ConstraintManagers of a similar nature
  and put them in a parent class called 'SimpleConstraintManager'.

RangeConstraintManager:
- Added a new prototype ConstraintManager to track ranges of variables! This
  ConstraintManager keeps tracks of ranges of concrete integers that a symbolic
  integer may have.

AnalysisConsumer:
- Add driver option to use RangeConstraintManager with GRExprEngine-based
  analyses.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64558 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/RangeConstraintManager.cpp b/lib/Analysis/RangeConstraintManager.cpp
new file mode 100644
index 0000000..06f26ce
--- /dev/null
+++ b/lib/Analysis/RangeConstraintManager.cpp
@@ -0,0 +1,720 @@
+//== 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 GRState.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SimpleConstraintManager.h"
+#include "clang/Analysis/PathSensitive/GRState.h"
+#include "clang/Analysis/PathSensitive/GRStateTrait.h"
+#include "clang/Analysis/PathSensitive/GRTransferFuncs.h"
+#include "clang/Driver/ManagerRegistry.h"
+#include "llvm/Support/Compiler.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;
+
+namespace { class VISIBILITY_HIDDEN ConstRange {}; }
+
+static int ConstRangeIndex = 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.
+class Range : public std::pair<llvm::APSInt, llvm::APSInt> {
+public:
+  Range(const llvm::APSInt &from, const llvm::APSInt &to)
+    : std::pair<llvm::APSInt, 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 *HasConcreteValue() const {
+    return From() == To() ? &From() : NULL;
+  }
+
+  void Profile(llvm::FoldingSetNodeID &ID) const {
+    From().Profile(ID);
+    To().Profile(ID);
+  }
+};
+
+struct RangeCmp {
+  bool operator()(const Range &r1, const Range &r2) {
+    if (r1.From() < r2.From()) {
+      assert(!r1.Includes(r2.From()));
+      assert(!r2.Includes(r1.To()));
+      return true;
+    } else if (r1.From() > r2.From()) {
+      assert(!r1.Includes(r2.To()));
+      assert(!r2.Includes(r1.From()));
+      return false;
+    } else
+      assert(!"Ranges should never be equal in the same set");
+  }
+};
+
+typedef llvm::ImmutableSet<Range> PrimRangeSet;
+
+class RangeSet;
+std::ostream &operator<<(std::ostream &os, const RangeSet &r);
+
+
+// A RangeSet contains a set of ranges. If the set is empty, then
+//   noValues -> Nothing matches.
+//  !noValues -> Everything (in range of the bit representation) matches.
+class RangeSet {
+  PrimRangeSet ranges; // no need to make const, since it is an
+                       // ImmutableSet - this allows default operator=
+                       // to work.
+  bool noValues;  // if true, no value is possible (should never happen)
+
+  static const llvm::APSInt Max(const llvm::APSInt &v) {
+    return llvm::APSInt::getMaxValue(v.getBitWidth(), v.isUnsigned());
+  }
+  static const llvm::APSInt Min(const llvm::APSInt &v) {
+     return llvm::APSInt::getMinValue(v.getBitWidth(), v.isUnsigned());
+  }
+  static const llvm::APSInt One(const llvm::APSInt &v) {
+    return llvm::APSInt(llvm::APInt(v.getBitWidth(), 1), v.isUnsigned());
+  }
+
+public:
+  // Create a RangeSet that allows all possible values.
+  RangeSet(PrimRangeSet::Factory *factory) : ranges(factory->GetEmptySet()),
+                                             noValues(false) {
+  }
+  // Note that if the empty set is passed, then there are no possible
+  // values.  To create a RangeSet that covers all values when the
+  // empty set is passed, use RangeSet(r, false).
+  RangeSet(const PrimRangeSet &r) : ranges(r), noValues(r.isEmpty()) {
+  }
+  // Allow an empty set to be passed meaning "all values" instead of
+  // "no values".
+  RangeSet(const PrimRangeSet &r, bool n) : ranges(r), noValues(n) {
+    assert(!n);
+  }
+  void Profile(llvm::FoldingSetNodeID &ID) const {
+    ranges.Profile(ID);
+    ID.AddBoolean(noValues);
+  }
+
+  const llvm::APSInt *HasConcreteValue() const {
+    if (!ranges.isSingleton())
+      return NULL;
+    return ranges.begin()->HasConcreteValue();
+  }
+
+  bool CouldBeNE(const llvm::APSInt &ne) const {
+    DOUT << "CouldBeNE(" << ne.toString(10) << ") " << *this << std::endl;
+    assert(!noValues);
+    const llvm::APSInt *v = HasConcreteValue();
+    if (v && *v == ne)
+        return false;
+    return true;
+  }
+
+  bool CouldBeEQ(const llvm::APSInt &eq) const {
+    DOUT << "CouldBeEQ(" << eq.toString(10) << ") " << *this << std::endl;
+    assert(!noValues);
+    if (ranges.isEmpty())
+      return true;
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i)
+      if (i->Includes(eq))
+        return true;
+    return false;
+  }
+
+  bool CouldBeLT(const llvm::APSInt &lt) const {
+    DOUT << "CouldBeLT(" << lt.toString(10) << ") " << *this << std::endl;
+    assert(!noValues);
+    // FIXME: should test if lt == min -> false here, since that's
+    // impossible to meet.
+    if (ranges.isEmpty())
+      return true;
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i)
+      if (i->From() < lt)
+        return true;
+    return false;
+  }
+
+  bool CouldBeLE(const llvm::APSInt &le) const {
+    DOUT << "CouldBeLE(" << le.toString(10) << ") " << *this << std::endl;
+    assert(!noValues);
+    if (ranges.isEmpty())
+      return true;
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i)
+      if (i->From() <= le)
+        return true;
+    return false;
+  }
+
+  bool CouldBeGT(const llvm::APSInt &gt) const {
+    DOUT << "CouldBeGT(" << gt.toString(10) << ") " << *this << std::endl;
+    assert(!noValues);
+    // FIXME: should we test if gt == max -> false here, since that's
+    // impossible to meet.
+    if (ranges.isEmpty())
+      return true;
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i)
+      if (i->To() > gt)
+        return true;
+    return false;
+  }
+
+  bool CouldBeGE(const llvm::APSInt &ge) const {
+    DOUT << "CouldBeGE(" << ge.toString(10) << ") " << *this << std::endl;
+    assert(!noValues);
+    if (ranges.isEmpty())
+      return true;
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i)
+      if (i->To() >= ge)
+        return true;
+    return false;
+  }
+
+  // Make all existing ranges fall within this new range
+  RangeSet Restrict(PrimRangeSet::Factory *factory, const llvm::APSInt &from,
+                    const llvm::APSInt &to) const {
+    if (ranges.isEmpty())
+      return factory->Add(ranges, Range(from, to));;
+
+    PrimRangeSet newRanges = factory->GetEmptySet();
+
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i) {
+      if (i->Includes(from)) {
+        if (i->Includes(to)) {
+          newRanges = factory->Add(newRanges, Range(from, to));
+        } else {
+          newRanges = factory->Add(newRanges, Range(from, i->To()));
+        }
+      } else if (i->Includes(to)) {
+        newRanges = factory->Add(newRanges, Range(i->From(), to));
+      }
+    }
+    return RangeSet(newRanges);
+  }
+
+  // Create a new RangeSet with the additional constraint that the
+  // range must be == eq. In other words the range becomes [eq,
+  // eq]. Note that this RangeSet must have included eq in the first
+  // place, or we shouldn't be here.
+  RangeSet AddEQ(PrimRangeSet::Factory *factory, const llvm::APSInt &eq) {
+    DOUT << "AddEQ(" << eq.toString(10) << ") " << *this << " -> ";
+    assert(CouldBeEQ(eq));
+    RangeSet r(factory->Add(factory->GetEmptySet(), Range(eq, eq)));
+    DOUT << r << std::endl;
+    return r;
+  }
+
+  RangeSet AddNE(PrimRangeSet::Factory *factory, const llvm::APSInt &ne) {
+    DOUT << "AddNE(" << ne.toString(10) << ") " << *this << " -> ";
+
+    const llvm::APSInt max = Max(ne);
+    const llvm::APSInt min = Min(ne);
+    const llvm::APSInt one = One(ne);
+
+    PrimRangeSet newRanges = factory->GetEmptySet();
+
+    if (ranges.isEmpty()) {
+      if (ne != max)
+        newRanges = factory->Add(newRanges, Range(ne + one, max));
+      if (ne != min)
+        newRanges = factory->Add(newRanges, Range(min, ne - one));
+      RangeSet r(newRanges);
+      DOUT << r << std::endl;
+      return r;
+    }
+
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i) {
+      if (i->Includes(ne)) {
+        if (ne != i->From())
+          newRanges = factory->Add(newRanges, Range(i->From(), ne - one));
+        if (ne != i->To())
+          newRanges = factory->Add(newRanges, Range(ne + one, i->To()));
+      } else {
+        newRanges = factory->Add(newRanges, *i);
+      }
+    }
+    RangeSet r(newRanges);
+    DOUT << r << std::endl;
+    return r;
+  }
+
+  RangeSet AddLT(PrimRangeSet::Factory *factory, const llvm::APSInt &lt) {
+    DOUT << "AddLT(" << lt.toString(10) << ") " << *this << " -> ";
+    const llvm::APSInt min = Min(lt);
+    const llvm::APSInt one = One(lt);
+
+    if (ranges.isEmpty()) {
+      PrimRangeSet pr = factory->GetEmptySet();
+      if (lt != min)
+        pr = factory->Add(pr, Range(min, lt - one));
+      RangeSet r(pr, false);
+      DOUT << r << std::endl;
+      return r;
+    }
+
+    PrimRangeSet newRanges = factory->GetEmptySet();
+
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i) {
+      if (i->Includes(lt) && i->From() < lt)
+        newRanges = factory->Add(newRanges, Range(i->From(), lt - one));
+      else if (i->To() < lt)
+        newRanges = factory->Add(newRanges, *i);
+    }
+    RangeSet r(newRanges);
+    DOUT << r << std::endl;
+    return r;
+  }
+
+  RangeSet AddLE(PrimRangeSet::Factory *factory, const llvm::APSInt &le) {
+    DOUT << "AddLE(" << le.toString(10) << ") " << *this << " -> ";
+    const llvm::APSInt min = Min(le);
+
+    if (ranges.isEmpty()) {
+      RangeSet r(factory->Add(ranges, Range(min, le)));
+      DOUT << r << std::endl;
+      return r;
+    }
+
+    PrimRangeSet newRanges = factory->GetEmptySet();
+
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i) {
+      // Strictly we should test for includes le + 1, but no harm is
+      // done by this formulation
+      if (i->Includes(le))
+        newRanges = factory->Add(newRanges, Range(i->From(), le));
+      else if (i->To() <= le)
+        newRanges = factory->Add(newRanges, *i);
+    }
+    RangeSet r(newRanges);
+    DOUT << r << std::endl;
+    return r;
+  }
+
+  RangeSet AddGT(PrimRangeSet::Factory *factory, const llvm::APSInt &gt) {
+    DOUT << "AddGT(" << gt.toString(10) << ") " << *this << " -> ";
+    const llvm::APSInt max = Max(gt);
+    const llvm::APSInt one = One(gt);
+
+    if (ranges.isEmpty()) {
+      RangeSet r(factory->Add(ranges, Range(gt + one, max)));
+      DOUT << r << std::endl;
+      return r;
+    }
+
+    PrimRangeSet newRanges = factory->GetEmptySet();
+
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i) {
+      if (i->Includes(gt) && i->To() > gt)
+        newRanges = factory->Add(newRanges, Range(gt + one, i->To()));
+      else if (i->From() > gt)
+        newRanges = factory->Add(newRanges, *i);
+    }
+    RangeSet r(newRanges);
+    DOUT << r << std::endl;
+    return r;
+  }
+
+  RangeSet AddGE(PrimRangeSet::Factory *factory, const llvm::APSInt &ge) {
+    DOUT << "AddGE(" << ge.toString(10) << ") " << *this << " -> ";
+    const llvm::APSInt max = Max(ge);
+
+    if (ranges.isEmpty()) {
+      RangeSet r(factory->Add(ranges, Range(ge, max)));
+      DOUT << r << std::endl;
+      return r;
+    }
+
+    PrimRangeSet newRanges = factory->GetEmptySet();
+
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i) {
+      // Strictly we should test for includes ge - 1, but no harm is
+      // done by this formulation
+      if (i->Includes(ge))
+        newRanges = factory->Add(newRanges, Range(ge, i->To()));
+      else if (i->From() >= ge)
+        newRanges = factory->Add(newRanges, *i);
+    }
+
+    RangeSet r(newRanges);
+    DOUT << r << std::endl;
+    return r;
+  }
+
+  void Print(std::ostream &os) const {
+    os << "{ ";
+    if (noValues) {
+      os << "**no values** }";
+      return;
+    }
+    for (PrimRangeSet::iterator i = ranges.begin() ; i != ranges.end() ; ++i) {
+      if (i != ranges.begin())
+        os << ", ";
+      os << '[' << i->From().toString(10) << ", " << i->To().toString(10)
+         << ']';
+    }
+    os << " }";
+  
+}
+  bool operator==(const RangeSet &other) const {
+    return ranges == other.ranges;
+  }
+};
+
+std::ostream &operator<<(std::ostream &os, const RangeSet &r) {
+  r.Print(os);
+  return os;
+}
+
+typedef llvm::ImmutableMap<SymbolRef,RangeSet> ConstRangeTy;
+
+namespace clang {
+template<>
+struct GRStateTrait<ConstRange> : public GRStatePartialTrait<ConstRangeTy> {
+  static inline void* GDMIndex() { return &ConstRangeIndex; }  
+};
+}  
+  
+namespace {
+class VISIBILITY_HIDDEN RangeConstraintManager
+  : public SimpleConstraintManager {
+public:
+  RangeConstraintManager(GRStateManager& statemgr) 
+      : SimpleConstraintManager(statemgr) {}
+
+  const GRState* AssumeSymNE(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V, bool& isFeasible);
+
+  const GRState* AssumeSymEQ(const GRState* St, SymbolRef sym,
+                                const llvm::APSInt& V, bool& isFeasible);
+
+  const GRState* AssumeSymLT(const GRState* St, SymbolRef sym,
+                                    const llvm::APSInt& V, bool& isFeasible);
+
+  const GRState* AssumeSymGT(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V, bool& isFeasible);
+
+  const GRState* AssumeSymGE(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V, bool& isFeasible);
+
+  const GRState* AssumeSymLE(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V, bool& isFeasible);
+
+  const GRState* AddEQ(const GRState* St, SymbolRef sym, const llvm::APSInt& V);
+
+  const GRState* AddNE(const GRState* St, SymbolRef sym, const llvm::APSInt& V);
+
+  const GRState* AddLT(const GRState* St, SymbolRef sym, const llvm::APSInt& V);
+
+  const GRState* AddLE(const GRState* St, SymbolRef sym, const llvm::APSInt& V);
+
+  const GRState* AddGT(const GRState* St, SymbolRef sym, const llvm::APSInt& V);
+
+  const GRState* AddGE(const GRState* St, SymbolRef sym, const llvm::APSInt& V);
+
+  // FIXME: these two are required because they are pure virtual, but
+  // are they useful with ranges? Neither is used in this file.
+  const llvm::APSInt* getSymVal(const GRState* St, SymbolRef sym) const;
+  bool isEqual(const GRState* St, SymbolRef sym, const llvm::APSInt& V) const;
+
+  bool CouldBeEQ(const GRState* St, SymbolRef sym, const llvm::APSInt& V) const;
+  bool CouldBeNE(const GRState* St, SymbolRef sym, const llvm::APSInt& V) const;
+
+  bool CouldBeLT(const GRState* St, SymbolRef sym, const llvm::APSInt& V) const;
+  bool CouldBeLE(const GRState* St, SymbolRef sym, const llvm::APSInt& V) const;
+  bool CouldBeGT(const GRState* St, SymbolRef sym, const llvm::APSInt& V) const;
+  bool CouldBeGE(const GRState* St, SymbolRef sym, const llvm::APSInt& V) const;
+  const GRState* RemoveDeadBindings(const GRState* St, SymbolReaper& SymReaper);
+
+  void print(const GRState* St, std::ostream& Out, 
+             const char* nl, const char *sep);
+
+private:
+  PrimRangeSet::Factory factory;
+  BasicValueFactory& getBasicVals() { return StateMgr.getBasicVals(); }
+};
+
+} // end anonymous namespace
+
+ConstraintManager* clang::CreateRangeConstraintManager(GRStateManager& StateMgr)
+{
+  return new RangeConstraintManager(StateMgr);
+}
+
+RegisterConstraintManager X(CreateRangeConstraintManager);
+
+const GRState*
+RangeConstraintManager::AssumeSymNE(const GRState* St, SymbolRef sym,
+                                    const llvm::APSInt& V, bool& isFeasible) {
+  isFeasible = CouldBeNE(St, sym, V);
+  if (isFeasible)
+    return AddNE(St, sym, V);
+  return St;
+}
+
+const GRState*
+RangeConstraintManager::AssumeSymEQ(const GRState* St, SymbolRef sym,
+                                    const llvm::APSInt& V, bool& isFeasible) {
+  isFeasible = CouldBeEQ(St, sym, V);
+  if (isFeasible)
+    return AddEQ(St, sym, V);
+  return St;
+}
+
+const GRState*
+RangeConstraintManager::AssumeSymLT(const GRState* St, SymbolRef sym,
+                                    const llvm::APSInt& V, bool& isFeasible) {
+  
+  // Is 'V' the smallest possible value?
+  if (V == llvm::APSInt::getMinValue(V.getBitWidth(), V.isUnsigned())) {
+    // sym cannot be any value less than 'V'.  This path is infeasible.
+    isFeasible = false;
+    return St;
+  }
+
+  isFeasible = CouldBeLT(St, sym, V);
+  if (isFeasible)
+    return AddLT(St, sym, V);
+
+  return St;
+}
+
+const GRState*
+RangeConstraintManager::AssumeSymGT(const GRState* St, SymbolRef sym,
+                                    const llvm::APSInt& V, bool& isFeasible) {
+
+  // Is 'V' the largest possible value?
+  if (V == llvm::APSInt::getMaxValue(V.getBitWidth(), V.isUnsigned())) {
+    // sym cannot be any value greater than 'V'.  This path is infeasible.
+    isFeasible = false;
+    return St;
+  }
+
+  isFeasible = CouldBeGT(St, sym, V);
+  if (isFeasible)
+    return AddGT(St, sym, V);
+
+  return St;
+}
+
+const GRState*
+RangeConstraintManager::AssumeSymGE(const GRState* St, SymbolRef sym,
+                                    const llvm::APSInt& V, bool& isFeasible) {
+
+  isFeasible = CouldBeGE(St, sym, V);
+  if (isFeasible)
+    return AddGE(St, sym, V);
+
+  return St;
+}
+
+const GRState*
+RangeConstraintManager::AssumeSymLE(const GRState* St, SymbolRef sym,
+                                    const llvm::APSInt& V, bool& isFeasible) {
+
+  isFeasible = CouldBeLT(St, sym, V);
+  if (isFeasible)
+    return AddLE(St, sym, V);
+    
+  return St;
+}
+
+const GRState* RangeConstraintManager::AddEQ(const GRState* St, SymbolRef sym,
+                                             const llvm::APSInt& V) {
+  // Create a new state with the old binding replaced.
+  GRStateRef state(St, StateMgr);
+  RangeSet R(&factory);
+  R = R.AddEQ(&factory, V);
+  return state.set<ConstRange>(sym, R);
+}
+
+const GRState* RangeConstraintManager::AddNE(const GRState* St, SymbolRef sym,
+                                             const llvm::APSInt& V) {
+  GRStateRef state(St, StateMgr);
+
+  ConstRangeTy::data_type* T = state.get<ConstRange>(sym);
+  RangeSet R(&factory);
+  if (T)
+    R = *T;
+  R = R.AddNE(&factory, V);
+  return state.set<ConstRange>(sym, R);
+}
+
+const GRState* RangeConstraintManager::AddLT(const GRState* St, SymbolRef sym,
+                                             const llvm::APSInt& V) {
+  GRStateRef state(St, StateMgr);
+
+  ConstRangeTy::data_type* T = state.get<ConstRange>(sym);
+  RangeSet R(&factory);
+  if (T)
+    R = *T;
+  R = R.AddLT(&factory, V);
+  return state.set<ConstRange>(sym, R);
+}
+
+const GRState* RangeConstraintManager::AddLE(const GRState* St, SymbolRef sym,
+                                             const llvm::APSInt& V) {
+  GRStateRef state(St, StateMgr);
+
+  ConstRangeTy::data_type* T = state.get<ConstRange>(sym);
+  RangeSet R(&factory);
+  if (T)
+    R = *T;
+  R = R.AddLE(&factory, V);
+  return state.set<ConstRange>(sym, R);
+}
+
+const GRState* RangeConstraintManager::AddGT(const GRState* St, SymbolRef sym,
+                                             const llvm::APSInt& V) {
+  GRStateRef state(St, StateMgr);
+
+  ConstRangeTy::data_type* T = state.get<ConstRange>(sym);
+  RangeSet R(&factory);
+  if (T)
+    R = *T;
+  R = R.AddGT(&factory, V);
+  return state.set<ConstRange>(sym, R);
+}
+
+const GRState* RangeConstraintManager::AddGE(const GRState* St, SymbolRef sym,
+                                             const llvm::APSInt& V) {
+  GRStateRef state(St, StateMgr);
+
+  ConstRangeTy::data_type* T = state.get<ConstRange>(sym);
+  RangeSet R(&factory);
+  if (T)
+    R = *T;
+  R = R.AddGE(&factory, V);
+  return state.set<ConstRange>(sym, R);
+}
+
+const llvm::APSInt* RangeConstraintManager::getSymVal(const GRState* St,
+                                                      SymbolRef sym) const {
+  const ConstRangeTy::data_type *T = St->get<ConstRange>(sym);
+  return T ? T->HasConcreteValue() : NULL;
+}
+
+bool RangeConstraintManager::CouldBeLT(const GRState* St, SymbolRef sym, 
+                                       const llvm::APSInt& V) const {
+  const ConstRangeTy::data_type *T = St->get<ConstRange>(sym);
+  return T ? T->CouldBeLT(V) : true;
+}
+
+bool RangeConstraintManager::CouldBeLE(const GRState* St, SymbolRef sym, 
+                                       const llvm::APSInt& V) const {
+  const ConstRangeTy::data_type *T = St->get<ConstRange>(sym);
+  return T ? T->CouldBeLE(V) : true;
+}
+
+bool RangeConstraintManager::CouldBeGT(const GRState* St, SymbolRef sym, 
+                                       const llvm::APSInt& V) const {
+  const ConstRangeTy::data_type *T = St->get<ConstRange>(sym);
+  return T ? T->CouldBeGT(V) : true;
+}
+
+bool RangeConstraintManager::CouldBeGE(const GRState* St, SymbolRef sym, 
+                                       const llvm::APSInt& V) const {
+  const ConstRangeTy::data_type *T = St->get<ConstRange>(sym);
+  return T ? T->CouldBeGE(V) : true;
+}
+
+bool RangeConstraintManager::CouldBeNE(const GRState* St, SymbolRef sym, 
+                                        const llvm::APSInt& V) const {
+  const ConstRangeTy::data_type *T = St->get<ConstRange>(sym);
+  return T ? T->CouldBeNE(V) : true;
+}
+
+bool RangeConstraintManager::CouldBeEQ(const GRState* St, SymbolRef sym, 
+                                        const llvm::APSInt& V) const {
+  const ConstRangeTy::data_type *T = St->get<ConstRange>(sym);
+  return T ? T->CouldBeEQ(V) : true;
+}
+
+bool RangeConstraintManager::isEqual(const GRState* St, SymbolRef sym,
+                                     const llvm::APSInt& V) const {
+  const llvm::APSInt *i = getSymVal(St, sym);
+  return i ? *i == V : false;
+}
+
+/// Scan all symbols referenced by the constraints. If the symbol is not alive
+/// as marked in LSymbols, mark it as dead in DSymbols.
+const GRState*
+RangeConstraintManager::RemoveDeadBindings(const GRState* St,
+                                           SymbolReaper& SymReaper) {
+  GRStateRef state(St, StateMgr);
+
+  ConstRangeTy CR = state.get<ConstRange>();
+  ConstRangeTy::Factory& CRFactory = state.get_context<ConstRange>();
+
+  for (ConstRangeTy::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<ConstRange>(CR);
+}
+
+void RangeConstraintManager::print(const GRState* St, std::ostream& Out, 
+                                   const char* nl, const char *sep) {
+#if 0
+  // Print equality constraints.
+
+  ConstEqTy CE = St->get<ConstEq>();
+
+  if (!CE.isEmpty()) {
+    Out << nl << sep << "'==' constraints:";
+
+    for (ConstEqTy::iterator I = CE.begin(), E = CE.end(); I!=E; ++I) {
+      Out << nl << " $" << I.getKey();
+      llvm::raw_os_ostream OS(Out);
+      OS << " : "   << *I.getData();
+    }
+  }
+
+  // Print != constraints.
+  
+  ConstNotEqTy CNE = St->get<ConstNotEq>();
+  
+  if (!CNE.isEmpty()) {
+    Out << nl << sep << "'!=' constraints:";
+  
+    for (ConstNotEqTy::iterator I = CNE.begin(), EI = CNE.end(); I!=EI; ++I) {
+      Out << nl << " $" << I.getKey() << " : ";
+      bool isFirst = true;
+    
+      GRState::IntSetTy::iterator J = I.getData().begin(), 
+                                  EJ = I.getData().end();      
+      
+      for ( ; J != EJ; ++J) {        
+        if (isFirst) isFirst = false;
+        else Out << ", ";
+      
+        Out << (*J)->getSExtValue(); // Hack: should print to raw_ostream.
+      }
+    }
+  }
+#endif  // 0
+
+  Out << nl << "Implement range printing";
+}