diff --git a/include/clang/Analysis/PathSensitive/BasicValueFactory.h b/include/clang/Analysis/PathSensitive/BasicValueFactory.h
index 9462ed597d..e36e521d79 100644
--- a/include/clang/Analysis/PathSensitive/BasicValueFactory.h
+++ b/include/clang/Analysis/PathSensitive/BasicValueFactory.h
@@ -71,8 +71,8 @@ public:
                                      const llvm::APSInt& V1,
                                      const llvm::APSInt& V2);
   
-  const std::pair<RVal, unsigned>&
-  getPersistentSizedRVal(const RVal& V, unsigned Bits);
+  const std::pair<RVal, uintptr_t>&
+  getPersistentRValWithData(const RVal& V, uintptr_t Data);
 };
 
 } // end clang namespace
diff --git a/include/clang/Analysis/PathSensitive/RValues.h b/include/clang/Analysis/PathSensitive/RValues.h
index 8a53588564..353046d4be 100644
--- a/include/clang/Analysis/PathSensitive/RValues.h
+++ b/include/clang/Analysis/PathSensitive/RValues.h
@@ -234,17 +234,20 @@ public:
 };
   
 class LValAsInteger : public NonLVal {
-  LValAsInteger(const std::pair<RVal, unsigned>& data) :
-    NonLVal(LValAsIntegerKind, &data) {}
+  LValAsInteger(const std::pair<RVal, uintptr_t>& data) :
+    NonLVal(LValAsIntegerKind, &data) {
+      assert (isa<LVal>(data.first));
+    }
   
 public:
     
   LVal getLVal() const {
-    return cast<LVal>(((std::pair<RVal, unsigned>*) Data)->first);
+    return cast<LVal>(((std::pair<RVal, uintptr_t>*) Data)->first);
   }
   
   const LVal& getPersistentLVal() const {
-    return cast<LVal>(((std::pair<RVal, unsigned>*) Data)->first);
+    const RVal& V = ((std::pair<RVal, uintptr_t>*) Data)->first;
+    return cast<LVal>(V);
   }    
   
   unsigned getNumBits() const {
@@ -263,7 +266,7 @@ public:
   
   static inline LValAsInteger Make(BasicValueFactory& Vals, LVal V,
                                    unsigned Bits) {    
-    return LValAsInteger(Vals.getPersistentSizedRVal(V, Bits));
+    return LValAsInteger(Vals.getPersistentRValWithData(V, Bits));
   }
 };
   
@@ -276,7 +279,7 @@ public:
 namespace lval {
   
 enum Kind { SymbolValKind, GotoLabelKind, DeclValKind, FuncValKind,
-            ConcreteIntKind, StringLiteralValKind };
+            ConcreteIntKind, StringLiteralValKind, FieldOffsetKind };
 
 class SymbolVal : public LVal {
 public:
@@ -409,7 +412,48 @@ public:
     return V->getSubKind() == StringLiteralValKind;
   }
 };  
+  
+class FieldOffset : public LVal {
+  FieldOffset(const std::pair<RVal, uintptr_t>& data)
+    : LVal(FieldOffsetKind, &data) {
+      assert (isa<LVal>(data.first));
+    }
+  
+public:
+  
+  LVal getBase() const {
+    return reinterpret_cast<const std::pair<LVal,uintptr_t>*> (Data)->first;
+  }  
+  
+  const LVal& getPersistentBase() const {
+    return reinterpret_cast<const std::pair<LVal,uintptr_t>*> (Data)->first;
+  }    
+  
     
+  FieldDecl* getFieldDecl() const {    
+    return (FieldDecl*)
+      reinterpret_cast<const std::pair<LVal,uintptr_t>*> (Data)->second;
+  }
+
+  // Implement isa<T> support.
+  static inline bool classof(const RVal* V) {
+    return V->getBaseKind() == LValKind &&
+           V->getSubKind() == FieldOffsetKind;
+  }
+  
+  static inline bool classof(const LVal* V) {
+    return V->getSubKind() == FieldOffsetKind;
+  }
+
+  static inline RVal Make(BasicValueFactory& Vals, RVal Base, FieldDecl* D) {
+    
+    if (Base.isUnknownOrUndef())
+      return Base;
+    
+    return FieldOffset(Vals.getPersistentRValWithData(cast<LVal>(Base),
+                                                      (uintptr_t) D));
+  }
+};
   
 } // end clang::lval namespace
 } // end clang namespace  
diff --git a/lib/Analysis/BasicValueFactory.cpp b/lib/Analysis/BasicValueFactory.cpp
index 22fb2d1b6e..b0aa79e067 100644
--- a/lib/Analysis/BasicValueFactory.cpp
+++ b/lib/Analysis/BasicValueFactory.cpp
@@ -18,18 +18,18 @@
 
 using namespace clang;
 
-typedef std::pair<RVal, unsigned> SizedRVal;
+typedef std::pair<RVal, uintptr_t> RValData;
 
 namespace llvm {
-template<> struct FoldingSetTrait<SizedRVal> {
-  static inline void Profile(const SizedRVal& X, llvm::FoldingSetNodeID& ID) {
+template<> struct FoldingSetTrait<RValData> {
+  static inline void Profile(const RValData& X, llvm::FoldingSetNodeID& ID) {
     X.first.Profile(ID);
-    ID.AddInteger(X.second);
+    ID.AddPointer( (void*) X.second);
   }
 };
 }
 
-typedef llvm::FoldingSet<llvm::FoldingSetNodeWrapper<SizedRVal> >
+typedef llvm::FoldingSet<llvm::FoldingSetNodeWrapper<RValData> >
   PersistentRValsTy;
 
 BasicValueFactory::~BasicValueFactory() {
@@ -184,8 +184,8 @@ BasicValueFactory::EvaluateAPSInt(BinaryOperator::Opcode Op,
 }
 
 
-const std::pair<RVal, unsigned>&
-BasicValueFactory::getPersistentSizedRVal(const RVal& V, unsigned Bits) {
+const std::pair<RVal, uintptr_t>&
+BasicValueFactory::getPersistentRValWithData(const RVal& V, uintptr_t Data) {
   
   // Lazily create the folding set.
   if (!PersistentRVals) PersistentRVals = new PersistentRValsTy();
@@ -193,18 +193,18 @@ BasicValueFactory::getPersistentSizedRVal(const RVal& V, unsigned Bits) {
   llvm::FoldingSetNodeID ID;
   void* InsertPos;
   V.Profile(ID);
-  ID.AddInteger(Bits);
+  ID.AddPointer((void*) Data);
   
   PersistentRValsTy& Map = *((PersistentRValsTy*) PersistentRVals);
   
-  typedef llvm::FoldingSetNodeWrapper<SizedRVal> FoldNodeTy;
+  typedef llvm::FoldingSetNodeWrapper<RValData> FoldNodeTy;
   FoldNodeTy* P = Map.FindNodeOrInsertPos(ID, InsertPos);
   
   if (!P) {  
     P = (FoldNodeTy*) BPAlloc.Allocate<FoldNodeTy>();
-    new (P) FoldNodeTy(std::make_pair(V, Bits));
+    new (P) FoldNodeTy(std::make_pair(V, Data));
     Map.InsertNode(P, InsertPos);
   }
 
-  return *P;
+  return P->getValue();
 }
diff --git a/lib/Analysis/GRExprEngine.cpp b/lib/Analysis/GRExprEngine.cpp
index 2353058e76..a4f1a0512d 100644
--- a/lib/Analysis/GRExprEngine.cpp
+++ b/lib/Analysis/GRExprEngine.cpp
@@ -856,16 +856,12 @@ void GRExprEngine::VisitMemberExpr(MemberExpr* M, NodeTy* Pred,
     // This is a redunant copy; we do this as a placeholder for future logic.
     for (NodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
       ValueState* St = GetState(*I);
-      RVal V = GetRVal(St, Base);
+      RVal BaseV = GetRVal(St, Base);      
 
-      // TODO: Compute the LVal for the field.  This will enable field
-      //  sensitivity for the analysis.
-      
-      if (!(V.isUndef() || V.isUnknown() || isa<lval::ConcreteInt>(V)))
-        V = UnknownVal();      
-      
-      MakeNode(Dst, M, *I, SetRVal(St, M, V)); 
+      RVal V = lval::FieldOffset::Make(BasicVals, GetRVal(St, Base),
+                                       M->getMemberDecl());
       
+      MakeNode(Dst, M, *I, SetRVal(St, M, V));      
     }
 
     return;
@@ -879,13 +875,8 @@ void GRExprEngine::VisitMemberExpr(MemberExpr* M, NodeTy* Pred,
   for (NodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
     ValueState* St = GetState(*I);
     
-    RVal V = GetRVal(St, Base);
-    
-    // TODO: Compute the LVal for the field.  This will enable field
-    //  sensitivity for the analysis.
-    
-    if (!(V.isUndef() || V.isUnknown() || isa<lval::ConcreteInt>(V)))
-      V = UnknownVal();
+    RVal V = lval::FieldOffset::Make(BasicVals, GetRVal(St, Base),
+                                     M->getMemberDecl());
     
     EvalLoad(Dst, M, *I, St, V, true);
   }
@@ -2034,7 +2025,11 @@ ValueState* GRExprEngine::AssumeAux(ValueState* St, LVal Cond,
     case lval::StringLiteralValKind:
       isFeasible = Assumption;
       return St;
-
+      
+    case lval::FieldOffsetKind:
+      return AssumeAux(St, cast<lval::FieldOffset>(Cond).getBase(),
+                       Assumption, isFeasible);
+      
     case lval::ConcreteIntKind: {
       bool b = cast<lval::ConcreteInt>(Cond).getValue() != 0;
       isFeasible = b ? Assumption : !Assumption;      
diff --git a/lib/Analysis/RValues.cpp b/lib/Analysis/RValues.cpp
index 5e161f34a5..ab1cf6a420 100644
--- a/lib/Analysis/RValues.cpp
+++ b/lib/Analysis/RValues.cpp
@@ -25,6 +25,9 @@ using llvm::APSInt;
 //===----------------------------------------------------------------------===//
 
 RVal::symbol_iterator RVal::symbol_begin() const {
+  
+  // FIXME: This is a rat's nest.  Cleanup.
+
   if (isa<lval::SymbolVal>(this))
     return (symbol_iterator) (&Data);
   else if (isa<nonlval::SymbolVal>(this))
@@ -39,7 +42,10 @@ RVal::symbol_iterator RVal::symbol_begin() const {
     const nonlval::LValAsInteger& V = cast<nonlval::LValAsInteger>(*this);
     return  V.getPersistentLVal().symbol_begin();
   }
-  
+  else if (isa<lval::FieldOffset>(this)) {
+    const lval::FieldOffset& V = cast<lval::FieldOffset>(*this);
+    return V.getPersistentBase().symbol_begin();
+  }
   return NULL;
 }
 
@@ -402,6 +408,13 @@ void LVal::print(std::ostream& Out) const {
           << "\"";
       break;
       
+    case lval::FieldOffsetKind: {
+      const lval::FieldOffset& C = *cast<lval::FieldOffset>(this);
+      C.getBase().print(Out);
+      Out << "." << C.getFieldDecl()->getName() << " (field LVal)";
+      break;
+    }
+      
     default:
       assert (false && "Pretty-printing not implemented for this LVal.");
       break;
diff --git a/lib/Analysis/ValueState.cpp b/lib/Analysis/ValueState.cpp
index cba0253ea1..e51366d666 100644
--- a/lib/Analysis/ValueState.cpp
+++ b/lib/Analysis/ValueState.cpp
@@ -212,6 +212,9 @@ RVal ValueStateManager::GetRVal(ValueState* St, LVal LV, QualType T) {
       return UnknownVal();
     }
       
+    case lval::FieldOffsetKind:
+      return UnknownVal();
+      
     case lval::FuncValKind:
       return LV;