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diff --git a/include/clang/StaticAnalyzer/Core/PathSensitive/ConstraintManager.h b/include/clang/StaticAnalyzer/Core/PathSensitive/ConstraintManager.h
new file mode 100644
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+++ b/include/clang/StaticAnalyzer/Core/PathSensitive/ConstraintManager.h
@@ -0,0 +1,158 @@
+//== ConstraintManager.h - Constraints on symbolic values.-------*- C++ -*--==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defined the interface to manage constraints on symbolic values.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_GR_CONSTRAINT_MANAGER_H
+#define LLVM_CLANG_GR_CONSTRAINT_MANAGER_H
+
+#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
+#include "llvm/Support/SaveAndRestore.h"
+
+namespace llvm {
+class APSInt;
+}
+
+namespace clang {
+namespace ento {
+
+class SubEngine;
+
+class ConditionTruthVal {
+  Optional<bool> Val;
+public:
+  /// Construct a ConditionTruthVal indicating the constraint is constrained
+  /// to either true or false, depending on the boolean value provided.
+  ConditionTruthVal(bool constraint) : Val(constraint) {}
+
+  /// Construct a ConstraintVal indicating the constraint is underconstrained.
+  ConditionTruthVal() {}
+  
+  /// Return true if the constraint is perfectly constrained to 'true'.
+  bool isConstrainedTrue() const {
+    return Val.hasValue() && Val.getValue();
+  }
+
+  /// Return true if the constraint is perfectly constrained to 'false'.
+  bool isConstrainedFalse() const {
+    return Val.hasValue() && !Val.getValue();
+  }
+
+  /// Return true if the constrained is perfectly constrained.
+  bool isConstrained() const {
+    return Val.hasValue();
+  }
+
+  /// Return true if the constrained is underconstrained and we do not know
+  /// if the constraint is true of value.
+  bool isUnderconstrained() const {
+    return !Val.hasValue();
+  }
+};
+  
+class ConstraintManager {
+public:
+  ConstraintManager() : NotifyAssumeClients(true) {}
+  
+  virtual ~ConstraintManager();
+  virtual ProgramStateRef assume(ProgramStateRef state,
+                                 DefinedSVal Cond,
+                                 bool Assumption) = 0;
+
+  typedef std::pair<ProgramStateRef, ProgramStateRef> ProgramStatePair;
+
+  /// Returns a pair of states (StTrue, StFalse) where the given condition is
+  /// assumed to be true or false, respectively.
+  ProgramStatePair assumeDual(ProgramStateRef State, DefinedSVal Cond) {
+    ProgramStateRef StTrue = assume(State, Cond, true);
+
+    // If StTrue is infeasible, asserting the falseness of Cond is unnecessary
+    // because the existing constraints already establish this.
+    if (!StTrue) {
+#ifndef __OPTIMIZE__
+      // This check is expensive and should be disabled even in Release+Asserts
+      // builds.
+      // FIXME: __OPTIMIZE__ is a GNU extension that Clang implements but MSVC
+      // does not. Is there a good equivalent there?
+      assert(assume(State, Cond, false) && "System is over constrained.");
+#endif
+      return ProgramStatePair((ProgramStateRef)nullptr, State);
+    }
+
+    ProgramStateRef StFalse = assume(State, Cond, false);
+    if (!StFalse) {
+      // We are careful to return the original state, /not/ StTrue,
+      // because we want to avoid having callers generate a new node
+      // in the ExplodedGraph.
+      return ProgramStatePair(State, (ProgramStateRef)nullptr);
+    }
+
+    return ProgramStatePair(StTrue, StFalse);
+  }
+
+  /// \brief If a symbol is perfectly constrained to a constant, attempt
+  /// to return the concrete value.
+  ///
+  /// Note that a ConstraintManager is not obligated to return a concretized
+  /// value for a symbol, even if it is perfectly constrained.
+  virtual const llvm::APSInt* getSymVal(ProgramStateRef state,
+                                        SymbolRef sym) const {
+    return nullptr;
+  }
+
+  virtual ProgramStateRef removeDeadBindings(ProgramStateRef state,
+                                                 SymbolReaper& SymReaper) = 0;
+
+  virtual void print(ProgramStateRef state,
+                     raw_ostream &Out,
+                     const char* nl,
+                     const char *sep) = 0;
+
+  virtual void EndPath(ProgramStateRef state) {}
+  
+  /// Convenience method to query the state to see if a symbol is null or
+  /// not null, or if neither assumption can be made.
+  ConditionTruthVal isNull(ProgramStateRef State, SymbolRef Sym) {
+    SaveAndRestore<bool> DisableNotify(NotifyAssumeClients, false);
+
+    return checkNull(State, Sym);
+  }
+
+protected:
+  /// A flag to indicate that clients should be notified of assumptions.
+  /// By default this is the case, but sometimes this needs to be restricted
+  /// to avoid infinite recursions within the ConstraintManager.
+  ///
+  /// Note that this flag allows the ConstraintManager to be re-entrant,
+  /// but not thread-safe.
+  bool NotifyAssumeClients;
+
+  /// canReasonAbout - Not all ConstraintManagers can accurately reason about
+  ///  all SVal values.  This method returns true if the ConstraintManager can
+  ///  reasonably handle a given SVal value.  This is typically queried by
+  ///  ExprEngine to determine if the value should be replaced with a
+  ///  conjured symbolic value in order to recover some precision.
+  virtual bool canReasonAbout(SVal X) const = 0;
+
+  /// Returns whether or not a symbol is known to be null ("true"), known to be
+  /// non-null ("false"), or may be either ("underconstrained"). 
+  virtual ConditionTruthVal checkNull(ProgramStateRef State, SymbolRef Sym);
+};
+
+ConstraintManager* CreateRangeConstraintManager(ProgramStateManager& statemgr,
+                                                SubEngine *subengine);
+
+} // end GR namespace
+
+} // end clang namespace
+
+#endif