Merge branch 'master' of ssh://bitbucket.org/czan/honours

1 files changed, 2009 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/RegionStore.cpp b/clang/lib/StaticAnalyzer/Core/RegionStore.cpp
new file mode 100644
index 0000000..cc3ea8c
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Core/RegionStore.cpp
@@ -0,0 +1,2009 @@
+//== RegionStore.cpp - Field-sensitive store model --------------*- 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 a basic region store model. In this model, we do have field
+// sensitivity. But we assume nothing about the heap shape. So recursive data
+// structures are largely ignored. Basically we do 1-limiting analysis.
+// Parameter pointers are assumed with no aliasing. Pointee objects of
+// parameters are created lazily.
+//
+//===----------------------------------------------------------------------===//
+#include "clang/AST/CharUnits.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/Analysis/Analyses/LiveVariables.h"
+#include "clang/Analysis/AnalysisContext.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ObjCMessage.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
+#include "llvm/ADT/ImmutableList.h"
+#include "llvm/ADT/ImmutableMap.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace ento;
+using llvm::Optional;
+
+//===----------------------------------------------------------------------===//
+// Representation of binding keys.
+//===----------------------------------------------------------------------===//
+
+namespace {
+class BindingKey {
+public:
+  enum Kind { Direct = 0x0, Default = 0x1 };
+private:
+  llvm ::PointerIntPair<const MemRegion*, 1> P;
+  uint64_t Offset;
+
+  explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k)
+    : P(r, (unsigned) k), Offset(offset) {}
+public:
+
+  bool isDirect() const { return P.getInt() == Direct; }
+
+  const MemRegion *getRegion() const { return P.getPointer(); }
+  uint64_t getOffset() const { return Offset; }
+
+  void Profile(llvm::FoldingSetNodeID& ID) const {
+    ID.AddPointer(P.getOpaqueValue());
+    ID.AddInteger(Offset);
+  }
+
+  static BindingKey Make(const MemRegion *R, Kind k);
+
+  bool operator<(const BindingKey &X) const {
+    if (P.getOpaqueValue() < X.P.getOpaqueValue())
+      return true;
+    if (P.getOpaqueValue() > X.P.getOpaqueValue())
+      return false;
+    return Offset < X.Offset;
+  }
+
+  bool operator==(const BindingKey &X) const {
+    return P.getOpaqueValue() == X.P.getOpaqueValue() &&
+           Offset == X.Offset;
+  }
+
+  bool isValid() const {
+    return getRegion() != NULL;
+  }
+};
+} // end anonymous namespace
+
+BindingKey BindingKey::Make(const MemRegion *R, Kind k) {
+  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
+    const RegionRawOffset &O = ER->getAsArrayOffset();
+
+    // FIXME: There are some ElementRegions for which we cannot compute
+    // raw offsets yet, including regions with symbolic offsets. These will be
+    // ignored by the store.
+    return BindingKey(O.getRegion(), O.getOffset().getQuantity(), k);
+  }
+
+  return BindingKey(R, 0, k);
+}
+
+namespace llvm {
+  static inline
+  raw_ostream &operator<<(raw_ostream &os, BindingKey K) {
+    os << '(' << K.getRegion() << ',' << K.getOffset()
+       << ',' << (K.isDirect() ? "direct" : "default")
+       << ')';
+    return os;
+  }
+} // end llvm namespace
+
+//===----------------------------------------------------------------------===//
+// Actual Store type.
+//===----------------------------------------------------------------------===//
+
+typedef llvm::ImmutableMap<BindingKey, SVal> RegionBindings;
+
+//===----------------------------------------------------------------------===//
+// Fine-grained control of RegionStoreManager.
+//===----------------------------------------------------------------------===//
+
+namespace {
+struct minimal_features_tag {};
+struct maximal_features_tag {};
+
+class RegionStoreFeatures {
+  bool SupportsFields;
+public:
+  RegionStoreFeatures(minimal_features_tag) :
+    SupportsFields(false) {}
+
+  RegionStoreFeatures(maximal_features_tag) :
+    SupportsFields(true) {}
+
+  void enableFields(bool t) { SupportsFields = t; }
+
+  bool supportsFields() const { return SupportsFields; }
+};
+}
+
+//===----------------------------------------------------------------------===//
+// Main RegionStore logic.
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+class RegionStoreSubRegionMap : public SubRegionMap {
+public:
+  typedef llvm::ImmutableSet<const MemRegion*> Set;
+  typedef llvm::DenseMap<const MemRegion*, Set> Map;
+private:
+  Set::Factory F;
+  Map M;
+public:
+  bool add(const MemRegion* Parent, const MemRegion* SubRegion) {
+    Map::iterator I = M.find(Parent);
+
+    if (I == M.end()) {
+      M.insert(std::make_pair(Parent, F.add(F.getEmptySet(), SubRegion)));
+      return true;
+    }
+
+    I->second = F.add(I->second, SubRegion);
+    return false;
+  }
+
+  void process(SmallVectorImpl<const SubRegion*> &WL, const SubRegion *R);
+
+  ~RegionStoreSubRegionMap() {}
+
+  const Set *getSubRegions(const MemRegion *Parent) const {
+    Map::const_iterator I = M.find(Parent);
+    return I == M.end() ? NULL : &I->second;
+  }
+
+  bool iterSubRegions(const MemRegion* Parent, Visitor& V) const {
+    Map::const_iterator I = M.find(Parent);
+
+    if (I == M.end())
+      return true;
+
+    Set S = I->second;
+    for (Set::iterator SI=S.begin(),SE=S.end(); SI != SE; ++SI) {
+      if (!V.Visit(Parent, *SI))
+        return false;
+    }
+
+    return true;
+  }
+};
+
+void
+RegionStoreSubRegionMap::process(SmallVectorImpl<const SubRegion*> &WL,
+                                 const SubRegion *R) {
+  const MemRegion *superR = R->getSuperRegion();
+  if (add(superR, R))
+    if (const SubRegion *sr = dyn_cast<SubRegion>(superR))
+      WL.push_back(sr);
+}
+
+class RegionStoreManager : public StoreManager {
+  const RegionStoreFeatures Features;
+  RegionBindings::Factory RBFactory;
+
+public:
+  RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f)
+    : StoreManager(mgr),
+      Features(f),
+      RBFactory(mgr.getAllocator()) {}
+
+  SubRegionMap *getSubRegionMap(Store store) {
+    return getRegionStoreSubRegionMap(store);
+  }
+
+  RegionStoreSubRegionMap *getRegionStoreSubRegionMap(Store store);
+
+  Optional<SVal> getDirectBinding(RegionBindings B, const MemRegion *R);
+  /// getDefaultBinding - Returns an SVal* representing an optional default
+  ///  binding associated with a region and its subregions.
+  Optional<SVal> getDefaultBinding(RegionBindings B, const MemRegion *R);
+
+  /// setImplicitDefaultValue - Set the default binding for the provided
+  ///  MemRegion to the value implicitly defined for compound literals when
+  ///  the value is not specified.
+  StoreRef setImplicitDefaultValue(Store store, const MemRegion *R, QualType T);
+
+  /// ArrayToPointer - Emulates the "decay" of an array to a pointer
+  ///  type.  'Array' represents the lvalue of the array being decayed
+  ///  to a pointer, and the returned SVal represents the decayed
+  ///  version of that lvalue (i.e., a pointer to the first element of
+  ///  the array).  This is called by ExprEngine when evaluating
+  ///  casts from arrays to pointers.
+  SVal ArrayToPointer(Loc Array);
+
+  /// For DerivedToBase casts, create a CXXBaseObjectRegion and return it.
+  virtual SVal evalDerivedToBase(SVal derived, QualType basePtrType);
+
+  /// \brief Evaluates C++ dynamic_cast cast.
+  /// The callback may result in the following 3 scenarios:
+  ///  - Successful cast (ex: derived is subclass of base).
+  ///  - Failed cast (ex: derived is definitely not a subclass of base).
+  ///  - We don't know (base is a symbolic region and we don't have 
+  ///    enough info to determine if the cast will succeed at run time).
+  /// The function returns an SVal representing the derived class; it's
+  /// valid only if Failed flag is set to false.
+  virtual SVal evalDynamicCast(SVal base, QualType derivedPtrType,bool &Failed);
+
+  StoreRef getInitialStore(const LocationContext *InitLoc) {
+    return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this);
+  }
+
+  //===-------------------------------------------------------------------===//
+  // Binding values to regions.
+  //===-------------------------------------------------------------------===//
+  RegionBindings invalidateGlobalRegion(MemRegion::Kind K,
+                                        const Expr *Ex,
+                                        unsigned Count,
+                                        const LocationContext *LCtx,
+                                        RegionBindings B,
+                                        InvalidatedRegions *Invalidated);
+
+  StoreRef invalidateRegions(Store store, ArrayRef<const MemRegion *> Regions,
+                             const Expr *E, unsigned Count,
+                             const LocationContext *LCtx,
+                             InvalidatedSymbols &IS,
+                             const CallOrObjCMessage *Call,
+                             InvalidatedRegions *Invalidated);
+
+public:   // Made public for helper classes.
+
+  void RemoveSubRegionBindings(RegionBindings &B, const MemRegion *R,
+                               RegionStoreSubRegionMap &M);
+
+  RegionBindings addBinding(RegionBindings B, BindingKey K, SVal V);
+
+  RegionBindings addBinding(RegionBindings B, const MemRegion *R,
+                     BindingKey::Kind k, SVal V);
+
+  const SVal *lookup(RegionBindings B, BindingKey K);
+  const SVal *lookup(RegionBindings B, const MemRegion *R, BindingKey::Kind k);
+
+  RegionBindings removeBinding(RegionBindings B, BindingKey K);
+  RegionBindings removeBinding(RegionBindings B, const MemRegion *R,
+                        BindingKey::Kind k);
+
+  RegionBindings removeBinding(RegionBindings B, const MemRegion *R) {
+    return removeBinding(removeBinding(B, R, BindingKey::Direct), R,
+                        BindingKey::Default);
+  }
+
+public: // Part of public interface to class.
+
+  StoreRef Bind(Store store, Loc LV, SVal V);
+
+  // BindDefault is only used to initialize a region with a default value.
+  StoreRef BindDefault(Store store, const MemRegion *R, SVal V) {
+    RegionBindings B = GetRegionBindings(store);
+    assert(!lookup(B, R, BindingKey::Default));
+    assert(!lookup(B, R, BindingKey::Direct));
+    return StoreRef(addBinding(B, R, BindingKey::Default, V)
+                      .getRootWithoutRetain(), *this);
+  }
+
+  StoreRef BindCompoundLiteral(Store store, const CompoundLiteralExpr *CL,
+                               const LocationContext *LC, SVal V);
+
+  StoreRef BindDecl(Store store, const VarRegion *VR, SVal InitVal);
+
+  StoreRef BindDeclWithNoInit(Store store, const VarRegion *) {
+    return StoreRef(store, *this);
+  }
+
+  /// BindStruct - Bind a compound value to a structure.
+  StoreRef BindStruct(Store store, const TypedValueRegion* R, SVal V);
+
+  StoreRef BindArray(Store store, const TypedValueRegion* R, SVal V);
+
+  /// KillStruct - Set the entire struct to unknown.
+  StoreRef KillStruct(Store store, const TypedRegion* R, SVal DefaultVal);
+
+  StoreRef Remove(Store store, Loc LV);
+
+  void incrementReferenceCount(Store store) {
+    GetRegionBindings(store).manualRetain();    
+  }
+  
+  /// If the StoreManager supports it, decrement the reference count of
+  /// the specified Store object.  If the reference count hits 0, the memory
+  /// associated with the object is recycled.
+  void decrementReferenceCount(Store store) {
+    GetRegionBindings(store).manualRelease();
+  }
+  
+  bool includedInBindings(Store store, const MemRegion *region) const;
+
+  /// \brief Return the value bound to specified location in a given state.
+  ///
+  /// The high level logic for this method is this:
+  /// getBinding (L)
+  ///   if L has binding
+  ///     return L's binding
+  ///   else if L is in killset
+  ///     return unknown
+  ///   else
+  ///     if L is on stack or heap
+  ///       return undefined
+  ///     else
+  ///       return symbolic
+  SVal getBinding(Store store, Loc L, QualType T = QualType());
+
+  SVal getBindingForElement(Store store, const ElementRegion *R);
+
+  SVal getBindingForField(Store store, const FieldRegion *R);
+
+  SVal getBindingForObjCIvar(Store store, const ObjCIvarRegion *R);
+
+  SVal getBindingForVar(Store store, const VarRegion *R);
+
+  SVal getBindingForLazySymbol(const TypedValueRegion *R);
+
+  SVal getBindingForFieldOrElementCommon(Store store, const TypedValueRegion *R,
+                                         QualType Ty, const MemRegion *superR);
+  
+  SVal getLazyBinding(const MemRegion *lazyBindingRegion,
+                      Store lazyBindingStore);
+
+  /// Get bindings for the values in a struct and return a CompoundVal, used
+  /// when doing struct copy:
+  /// struct s x, y;
+  /// x = y;
+  /// y's value is retrieved by this method.
+  SVal getBindingForStruct(Store store, const TypedValueRegion* R);
+
+  SVal getBindingForArray(Store store, const TypedValueRegion* R);
+
+  /// Used to lazily generate derived symbols for bindings that are defined
+  ///  implicitly by default bindings in a super region.
+  Optional<SVal> getBindingForDerivedDefaultValue(RegionBindings B,
+                                                  const MemRegion *superR,
+                                                  const TypedValueRegion *R,
+                                                  QualType Ty);
+
+  /// Get the state and region whose binding this region R corresponds to.
+  std::pair<Store, const MemRegion*>
+  GetLazyBinding(RegionBindings B, const MemRegion *R,
+                 const MemRegion *originalRegion);
+
+  StoreRef CopyLazyBindings(nonloc::LazyCompoundVal V, Store store,
+                            const TypedRegion *R);
+
+  //===------------------------------------------------------------------===//
+  // State pruning.
+  //===------------------------------------------------------------------===//
+
+  /// removeDeadBindings - Scans the RegionStore of 'state' for dead values.
+  ///  It returns a new Store with these values removed.
+  StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
+                              SymbolReaper& SymReaper);
+
+  StoreRef enterStackFrame(ProgramStateRef state,
+                           const LocationContext *callerCtx,
+                           const StackFrameContext *calleeCtx);
+
+  //===------------------------------------------------------------------===//
+  // Region "extents".
+  //===------------------------------------------------------------------===//
+
+  // FIXME: This method will soon be eliminated; see the note in Store.h.
+  DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state,
+                                         const MemRegion* R, QualType EleTy);
+
+  //===------------------------------------------------------------------===//
+  // Utility methods.
+  //===------------------------------------------------------------------===//
+
+  static inline RegionBindings GetRegionBindings(Store store) {
+    return RegionBindings(static_cast<const RegionBindings::TreeTy*>(store));
+  }
+
+  void print(Store store, raw_ostream &Out, const char* nl,
+             const char *sep);
+
+  void iterBindings(Store store, BindingsHandler& f) {
+    RegionBindings B = GetRegionBindings(store);
+    for (RegionBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I) {
+      const BindingKey &K = I.getKey();
+      if (!K.isDirect())
+        continue;
+      if (const SubRegion *R = dyn_cast<SubRegion>(I.getKey().getRegion())) {
+        // FIXME: Possibly incorporate the offset?
+        if (!f.HandleBinding(*this, store, R, I.getData()))
+          return;
+      }
+    }
+  }
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// RegionStore creation.
+//===----------------------------------------------------------------------===//
+
+StoreManager *ento::CreateRegionStoreManager(ProgramStateManager& StMgr) {
+  RegionStoreFeatures F = maximal_features_tag();
+  return new RegionStoreManager(StMgr, F);
+}
+
+StoreManager *
+ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) {
+  RegionStoreFeatures F = minimal_features_tag();
+  F.enableFields(true);
+  return new RegionStoreManager(StMgr, F);
+}
+
+
+RegionStoreSubRegionMap*
+RegionStoreManager::getRegionStoreSubRegionMap(Store store) {
+  RegionBindings B = GetRegionBindings(store);
+  RegionStoreSubRegionMap *M = new RegionStoreSubRegionMap();
+
+  SmallVector<const SubRegion*, 10> WL;
+
+  for (RegionBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I)
+    if (const SubRegion *R = dyn_cast<SubRegion>(I.getKey().getRegion()))
+      M->process(WL, R);
+
+  // We also need to record in the subregion map "intermediate" regions that
+  // don't have direct bindings but are super regions of those that do.
+  while (!WL.empty()) {
+    const SubRegion *R = WL.back();
+    WL.pop_back();
+    M->process(WL, R);
+  }
+
+  return M;
+}
+
+//===----------------------------------------------------------------------===//
+// Region Cluster analysis.
+//===----------------------------------------------------------------------===//
+
+namespace {
+template <typename DERIVED>
+class ClusterAnalysis  {
+protected:
+  typedef BumpVector<BindingKey> RegionCluster;
+  typedef llvm::DenseMap<const MemRegion *, RegionCluster *> ClusterMap;
+  llvm::DenseMap<const RegionCluster*, unsigned> Visited;
+  typedef SmallVector<std::pair<const MemRegion *, RegionCluster*>, 10>
+    WorkList;
+
+  BumpVectorContext BVC;
+  ClusterMap ClusterM;
+  WorkList WL;
+
+  RegionStoreManager &RM;
+  ASTContext &Ctx;
+  SValBuilder &svalBuilder;
+
+  RegionBindings B;
+  
+  const bool includeGlobals;
+
+public:
+  ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr,
+                  RegionBindings b, const bool includeGlobals)
+    : RM(rm), Ctx(StateMgr.getContext()),
+      svalBuilder(StateMgr.getSValBuilder()),
+      B(b), includeGlobals(includeGlobals) {}
+
+  RegionBindings getRegionBindings() const { return B; }
+
+  RegionCluster &AddToCluster(BindingKey K) {
+    const MemRegion *R = K.getRegion();
+    const MemRegion *baseR = R->getBaseRegion();
+    RegionCluster &C = getCluster(baseR);
+    C.push_back(K, BVC);
+    static_cast<DERIVED*>(this)->VisitAddedToCluster(baseR, C);
+    return C;
+  }
+
+  bool isVisited(const MemRegion *R) {
+    return (bool) Visited[&getCluster(R->getBaseRegion())];
+  }
+
+  RegionCluster& getCluster(const MemRegion *R) {
+    RegionCluster *&CRef = ClusterM[R];
+    if (!CRef) {
+      void *Mem = BVC.getAllocator().template Allocate<RegionCluster>();
+      CRef = new (Mem) RegionCluster(BVC, 10);
+    }
+    return *CRef;
+  }
+
+  void GenerateClusters() {
+      // Scan the entire set of bindings and make the region clusters.
+    for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){
+      RegionCluster &C = AddToCluster(RI.getKey());
+      if (const MemRegion *R = RI.getData().getAsRegion()) {
+        // Generate a cluster, but don't add the region to the cluster
+        // if there aren't any bindings.
+        getCluster(R->getBaseRegion());
+      }
+      if (includeGlobals) {
+        const MemRegion *R = RI.getKey().getRegion();
+        if (isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace()))
+          AddToWorkList(R, C);
+      }
+    }
+  }
+
+  bool AddToWorkList(const MemRegion *R, RegionCluster &C) {
+    if (unsigned &visited = Visited[&C])
+      return false;
+    else
+      visited = 1;
+
+    WL.push_back(std::make_pair(R, &C));
+    return true;
+  }
+
+  bool AddToWorkList(BindingKey K) {
+    return AddToWorkList(K.getRegion());
+  }
+
+  bool AddToWorkList(const MemRegion *R) {
+    const MemRegion *baseR = R->getBaseRegion();
+    return AddToWorkList(baseR, getCluster(baseR));
+  }
+
+  void RunWorkList() {
+    while (!WL.empty()) {
+      const MemRegion *baseR;
+      RegionCluster *C;
+      llvm::tie(baseR, C) = WL.back();
+      WL.pop_back();
+
+        // First visit the cluster.
+      static_cast<DERIVED*>(this)->VisitCluster(baseR, C->begin(), C->end());
+
+        // Next, visit the base region.
+      static_cast<DERIVED*>(this)->VisitBaseRegion(baseR);
+    }
+  }
+
+public:
+  void VisitAddedToCluster(const MemRegion *baseR, RegionCluster &C) {}
+  void VisitCluster(const MemRegion *baseR, BindingKey *I, BindingKey *E) {}
+  void VisitBaseRegion(const MemRegion *baseR) {}
+};
+}
+
+//===----------------------------------------------------------------------===//
+// Binding invalidation.
+//===----------------------------------------------------------------------===//
+
+void RegionStoreManager::RemoveSubRegionBindings(RegionBindings &B,
+                                                 const MemRegion *R,
+                                                 RegionStoreSubRegionMap &M) {
+
+  if (const RegionStoreSubRegionMap::Set *S = M.getSubRegions(R))
+    for (RegionStoreSubRegionMap::Set::iterator I = S->begin(), E = S->end();
+         I != E; ++I)
+      RemoveSubRegionBindings(B, *I, M);
+
+  B = removeBinding(B, R);
+}
+
+namespace {
+class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker>
+{
+  const Expr *Ex;
+  unsigned Count;
+  const LocationContext *LCtx;
+  StoreManager::InvalidatedSymbols &IS;
+  StoreManager::InvalidatedRegions *Regions;
+public:
+  invalidateRegionsWorker(RegionStoreManager &rm,
+                          ProgramStateManager &stateMgr,
+                          RegionBindings b,
+                          const Expr *ex, unsigned count,
+                          const LocationContext *lctx,
+                          StoreManager::InvalidatedSymbols &is,
+                          StoreManager::InvalidatedRegions *r,
+                          bool includeGlobals)
+    : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, includeGlobals),
+      Ex(ex), Count(count), LCtx(lctx), IS(is), Regions(r) {}
+
+  void VisitCluster(const MemRegion *baseR, BindingKey *I, BindingKey *E);
+  void VisitBaseRegion(const MemRegion *baseR);
+
+private:
+  void VisitBinding(SVal V);
+};
+}
+
+void invalidateRegionsWorker::VisitBinding(SVal V) {
+  // A symbol?  Mark it touched by the invalidation.
+  if (SymbolRef Sym = V.getAsSymbol())
+    IS.insert(Sym);
+
+  if (const MemRegion *R = V.getAsRegion()) {
+    AddToWorkList(R);
+    return;
+  }
+
+  // Is it a LazyCompoundVal?  All references get invalidated as well.
+  if (const nonloc::LazyCompoundVal *LCS =
+        dyn_cast<nonloc::LazyCompoundVal>(&V)) {
+
+    const MemRegion *LazyR = LCS->getRegion();
+    RegionBindings B = RegionStoreManager::GetRegionBindings(LCS->getStore());
+
+    for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){
+      const SubRegion *baseR = dyn_cast<SubRegion>(RI.getKey().getRegion());
+      if (baseR && baseR->isSubRegionOf(LazyR))
+        VisitBinding(RI.getData());
+    }
+
+    return;
+  }
+}
+
+void invalidateRegionsWorker::VisitCluster(const MemRegion *baseR,
+                                           BindingKey *I, BindingKey *E) {
+  for ( ; I != E; ++I) {
+    // Get the old binding.  Is it a region?  If so, add it to the worklist.
+    const BindingKey &K = *I;
+    if (const SVal *V = RM.lookup(B, K))
+      VisitBinding(*V);
+
+    B = RM.removeBinding(B, K);
+  }
+}
+
+void invalidateRegionsWorker::VisitBaseRegion(const MemRegion *baseR) {
+  // Symbolic region?  Mark that symbol touched by the invalidation.
+  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR))
+    IS.insert(SR->getSymbol());
+
+  // BlockDataRegion?  If so, invalidate captured variables that are passed
+  // by reference.
+  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) {
+    for (BlockDataRegion::referenced_vars_iterator
+         BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ;
+         BI != BE; ++BI) {
+      const VarRegion *VR = *BI;
+      const VarDecl *VD = VR->getDecl();
+      if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage())
+        AddToWorkList(VR);
+    }
+    return;
+  }
+
+  // Otherwise, we have a normal data region. Record that we touched the region.
+  if (Regions)
+    Regions->push_back(baseR);
+
+  if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) {
+    // Invalidate the region by setting its default value to
+    // conjured symbol. The type of the symbol is irrelavant.
+    DefinedOrUnknownSVal V =
+      svalBuilder.getConjuredSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
+    B = RM.addBinding(B, baseR, BindingKey::Default, V);
+    return;
+  }
+
+  if (!baseR->isBoundable())
+    return;
+
+  const TypedValueRegion *TR = cast<TypedValueRegion>(baseR);
+  QualType T = TR->getValueType();
+
+    // Invalidate the binding.
+  if (T->isStructureOrClassType()) {
+    // Invalidate the region by setting its default value to
+    // conjured symbol. The type of the symbol is irrelavant.
+    DefinedOrUnknownSVal V =
+      svalBuilder.getConjuredSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
+    B = RM.addBinding(B, baseR, BindingKey::Default, V);
+    return;
+  }
+
+  if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
+      // Set the default value of the array to conjured symbol.
+    DefinedOrUnknownSVal V =
+    svalBuilder.getConjuredSymbolVal(baseR, Ex, LCtx,
+                                     AT->getElementType(), Count);
+    B = RM.addBinding(B, baseR, BindingKey::Default, V);
+    return;
+  }
+  
+  if (includeGlobals && 
+      isa<NonStaticGlobalSpaceRegion>(baseR->getMemorySpace())) {
+    // If the region is a global and we are invalidating all globals,
+    // just erase the entry.  This causes all globals to be lazily
+    // symbolicated from the same base symbol.
+    B = RM.removeBinding(B, baseR);
+    return;
+  }
+  
+
+  DefinedOrUnknownSVal V = svalBuilder.getConjuredSymbolVal(baseR, Ex, LCtx,
+                                                            T,Count);
+  assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
+  B = RM.addBinding(B, baseR, BindingKey::Direct, V);
+}
+
+RegionBindings RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K,
+                                                          const Expr *Ex,
+                                                          unsigned Count,
+                                                    const LocationContext *LCtx,
+                                                          RegionBindings B,
+                                            InvalidatedRegions *Invalidated) {
+  // Bind the globals memory space to a new symbol that we will use to derive
+  // the bindings for all globals.
+  const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K);
+  SVal V =
+      svalBuilder.getConjuredSymbolVal(/* SymbolTag = */ (void*) GS, Ex, LCtx,
+          /* symbol type, doesn't matter */ Ctx.IntTy,
+          Count);
+
+  B = removeBinding(B, GS);
+  B = addBinding(B, BindingKey::Make(GS, BindingKey::Default), V);
+
+  // Even if there are no bindings in the global scope, we still need to
+  // record that we touched it.
+  if (Invalidated)
+    Invalidated->push_back(GS);
+
+  return B;
+}
+
+StoreRef RegionStoreManager::invalidateRegions(Store store,
+                                            ArrayRef<const MemRegion *> Regions,
+                                               const Expr *Ex, unsigned Count,
+                                               const LocationContext *LCtx,
+                                               InvalidatedSymbols &IS,
+                                               const CallOrObjCMessage *Call,
+                                              InvalidatedRegions *Invalidated) {
+  invalidateRegionsWorker W(*this, StateMgr,
+                            RegionStoreManager::GetRegionBindings(store),
+                            Ex, Count, LCtx, IS, Invalidated, false);
+
+  // Scan the bindings and generate the clusters.
+  W.GenerateClusters();
+
+  // Add the regions to the worklist.
+  for (ArrayRef<const MemRegion *>::iterator
+       I = Regions.begin(), E = Regions.end(); I != E; ++I)
+    W.AddToWorkList(*I);
+
+  W.RunWorkList();
+
+  // Return the new bindings.
+  RegionBindings B = W.getRegionBindings();
+
+  // For all globals which are not static nor immutable: determine which global
+  // regions should be invalidated and invalidate them.
+  // TODO: This could possibly be more precise with modules.
+  //
+  // System calls invalidate only system globals.
+  if (Call && Call->isInSystemHeader()) {
+    B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
+                               Ex, Count, LCtx, B, Invalidated);
+  // Internal calls might invalidate both system and internal globals.
+  } else {
+    B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
+                               Ex, Count, LCtx, B, Invalidated);
+    B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind,
+                               Ex, Count, LCtx, B, Invalidated);
+  }
+
+  return StoreRef(B.getRootWithoutRetain(), *this);
+}
+
+//===----------------------------------------------------------------------===//
+// Extents for regions.
+//===----------------------------------------------------------------------===//
+
+DefinedOrUnknownSVal
+RegionStoreManager::getSizeInElements(ProgramStateRef state,
+                                      const MemRegion *R,
+                                      QualType EleTy) {
+  SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder);
+  const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size);
+  if (!SizeInt)
+    return UnknownVal();
+
+  CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue());
+
+  if (Ctx.getAsVariableArrayType(EleTy)) {
+    // FIXME: We need to track extra state to properly record the size
+    // of VLAs.  Returning UnknownVal here, however, is a stop-gap so that
+    // we don't have a divide-by-zero below.
+    return UnknownVal();
+  }
+
+  CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy);
+
+  // If a variable is reinterpreted as a type that doesn't fit into a larger
+  // type evenly, round it down.
+  // This is a signed value, since it's used in arithmetic with signed indices.
+  return svalBuilder.makeIntVal(RegionSize / EleSize, false);
+}
+
+//===----------------------------------------------------------------------===//
+// Location and region casting.
+//===----------------------------------------------------------------------===//
+
+/// ArrayToPointer - Emulates the "decay" of an array to a pointer
+///  type.  'Array' represents the lvalue of the array being decayed
+///  to a pointer, and the returned SVal represents the decayed
+///  version of that lvalue (i.e., a pointer to the first element of
+///  the array).  This is called by ExprEngine when evaluating casts
+///  from arrays to pointers.
+SVal RegionStoreManager::ArrayToPointer(Loc Array) {
+  if (!isa<loc::MemRegionVal>(Array))
+    return UnknownVal();
+
+  const MemRegion* R = cast<loc::MemRegionVal>(&Array)->getRegion();
+  const TypedValueRegion* ArrayR = dyn_cast<TypedValueRegion>(R);
+
+  if (!ArrayR)
+    return UnknownVal();
+
+  // Strip off typedefs from the ArrayRegion's ValueType.
+  QualType T = ArrayR->getValueType().getDesugaredType(Ctx);
+  const ArrayType *AT = cast<ArrayType>(T);
+  T = AT->getElementType();
+
+  NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
+  return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, ArrayR, Ctx));
+}
+
+SVal RegionStoreManager::evalDerivedToBase(SVal derived, QualType baseType) {
+  const CXXRecordDecl *baseDecl;
+  if (baseType->isPointerType())
+    baseDecl = baseType->getCXXRecordDeclForPointerType();
+  else
+    baseDecl = baseType->getAsCXXRecordDecl();
+
+  assert(baseDecl && "not a CXXRecordDecl?");
+
+  loc::MemRegionVal *derivedRegVal = dyn_cast<loc::MemRegionVal>(&derived);
+  if (!derivedRegVal)
+    return derived;
+
+  const MemRegion *baseReg = 
+    MRMgr.getCXXBaseObjectRegion(baseDecl, derivedRegVal->getRegion()); 
+
+  return loc::MemRegionVal(baseReg);
+}
+
+SVal RegionStoreManager::evalDynamicCast(SVal base, QualType derivedType,
+                                         bool &Failed) {
+  Failed = false;
+
+  loc::MemRegionVal *baseRegVal = dyn_cast<loc::MemRegionVal>(&base);
+  if (!baseRegVal)
+    return UnknownVal();
+  const MemRegion *BaseRegion = baseRegVal->stripCasts();
+
+  // Assume the derived class is a pointer or a reference to a CXX record.
+  derivedType = derivedType->getPointeeType();
+  assert(!derivedType.isNull());
+  const CXXRecordDecl *DerivedDecl = derivedType->getAsCXXRecordDecl();
+  if (!DerivedDecl && !derivedType->isVoidType())
+    return UnknownVal();
+
+  // Drill down the CXXBaseObject chains, which represent upcasts (casts from
+  // derived to base).
+  const MemRegion *SR = BaseRegion;
+  while (const TypedRegion *TSR = dyn_cast_or_null<TypedRegion>(SR)) {
+    QualType BaseType = TSR->getLocationType()->getPointeeType();
+    assert(!BaseType.isNull());
+    const CXXRecordDecl *SRDecl = BaseType->getAsCXXRecordDecl();
+    if (!SRDecl)
+      return UnknownVal();
+
+    // If found the derived class, the cast succeeds.
+    if (SRDecl == DerivedDecl)
+      return loc::MemRegionVal(TSR);
+
+    // If the region type is a subclass of the derived type.
+    if (!derivedType->isVoidType() && SRDecl->isDerivedFrom(DerivedDecl)) {
+      // This occurs in two cases.
+      // 1) We are processing an upcast.
+      // 2) We are processing a downcast but we jumped directly from the
+      // ancestor to a child of the cast value, so conjure the
+      // appropriate region to represent value (the intermediate node).
+      return loc::MemRegionVal(MRMgr.getCXXBaseObjectRegion(DerivedDecl,
+                                                            BaseRegion));
+    }
+
+    // If super region is not a parent of derived class, the cast definitely
+    // fails.
+    if (!derivedType->isVoidType() &&
+        DerivedDecl->isProvablyNotDerivedFrom(SRDecl)) {
+      Failed = true;
+      return UnknownVal();
+    }
+
+    if (const CXXBaseObjectRegion *R = dyn_cast<CXXBaseObjectRegion>(TSR))
+      // Drill down the chain to get the derived classes.
+      SR = R->getSuperRegion();
+    else {
+      // We reached the bottom of the hierarchy.
+
+      // If this is a cast to void*, return the region.
+      if (derivedType->isVoidType())
+        return loc::MemRegionVal(TSR);
+
+      // We did not find the derived class. We we must be casting the base to
+      // derived, so the cast should fail.
+      Failed = true;
+      return UnknownVal();
+    }
+  }
+
+  return UnknownVal();
+}
+
+//===----------------------------------------------------------------------===//
+// Loading values from regions.
+//===----------------------------------------------------------------------===//
+
+Optional<SVal> RegionStoreManager::getDirectBinding(RegionBindings B,
+                                                    const MemRegion *R) {
+
+  if (const SVal *V = lookup(B, R, BindingKey::Direct))
+    return *V;
+
+  return Optional<SVal>();
+}
+
+Optional<SVal> RegionStoreManager::getDefaultBinding(RegionBindings B,
+                                                     const MemRegion *R) {
+  if (R->isBoundable())
+    if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R))
+      if (TR->getValueType()->isUnionType())
+        return UnknownVal();
+
+  if (const SVal *V = lookup(B, R, BindingKey::Default))
+    return *V;
+
+  return Optional<SVal>();
+}
+
+SVal RegionStoreManager::getBinding(Store store, Loc L, QualType T) {
+  assert(!isa<UnknownVal>(L) && "location unknown");
+  assert(!isa<UndefinedVal>(L) && "location undefined");
+
+  // For access to concrete addresses, return UnknownVal.  Checks
+  // for null dereferences (and similar errors) are done by checkers, not
+  // the Store.
+  // FIXME: We can consider lazily symbolicating such memory, but we really
+  // should defer this when we can reason easily about symbolicating arrays
+  // of bytes.
+  if (isa<loc::ConcreteInt>(L)) {
+    return UnknownVal();
+  }
+  if (!isa<loc::MemRegionVal>(L)) {
+    return UnknownVal();
+  }
+
+  const MemRegion *MR = cast<loc::MemRegionVal>(L).getRegion();
+
+  if (isa<AllocaRegion>(MR) ||
+      isa<SymbolicRegion>(MR) ||
+      isa<CodeTextRegion>(MR)) {
+    if (T.isNull()) {
+      if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
+        T = TR->getLocationType();
+      else {
+        const SymbolicRegion *SR = cast<SymbolicRegion>(MR);
+        T = SR->getSymbol()->getType(Ctx);
+      }
+    }
+    MR = GetElementZeroRegion(MR, T);
+  }
+
+  // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
+  //  instead of 'Loc', and have the other Loc cases handled at a higher level.
+  const TypedValueRegion *R = cast<TypedValueRegion>(MR);
+  QualType RTy = R->getValueType();
+
+  // FIXME: We should eventually handle funny addressing.  e.g.:
+  //
+  //   int x = ...;
+  //   int *p = &x;
+  //   char *q = (char*) p;
+  //   char c = *q;  // returns the first byte of 'x'.
+  //
+  // Such funny addressing will occur due to layering of regions.
+
+  if (RTy->isStructureOrClassType())
+    return getBindingForStruct(store, R);
+
+  // FIXME: Handle unions.
+  if (RTy->isUnionType())
+    return UnknownVal();
+
+  if (RTy->isArrayType())
+    return getBindingForArray(store, R);
+
+  // FIXME: handle Vector types.
+  if (RTy->isVectorType())
+    return UnknownVal();
+
+  if (const FieldRegion* FR = dyn_cast<FieldRegion>(R))
+    return CastRetrievedVal(getBindingForField(store, FR), FR, T, false);
+
+  if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
+    // FIXME: Here we actually perform an implicit conversion from the loaded
+    // value to the element type.  Eventually we want to compose these values
+    // more intelligently.  For example, an 'element' can encompass multiple
+    // bound regions (e.g., several bound bytes), or could be a subset of
+    // a larger value.
+    return CastRetrievedVal(getBindingForElement(store, ER), ER, T, false);
+  }
+
+  if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) {
+    // FIXME: Here we actually perform an implicit conversion from the loaded
+    // value to the ivar type.  What we should model is stores to ivars
+    // that blow past the extent of the ivar.  If the address of the ivar is
+    // reinterpretted, it is possible we stored a different value that could
+    // fit within the ivar.  Either we need to cast these when storing them
+    // or reinterpret them lazily (as we do here).
+    return CastRetrievedVal(getBindingForObjCIvar(store, IVR), IVR, T, false);
+  }
+
+  if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
+    // FIXME: Here we actually perform an implicit conversion from the loaded
+    // value to the variable type.  What we should model is stores to variables
+    // that blow past the extent of the variable.  If the address of the
+    // variable is reinterpretted, it is possible we stored a different value
+    // that could fit within the variable.  Either we need to cast these when
+    // storing them or reinterpret them lazily (as we do here).
+    return CastRetrievedVal(getBindingForVar(store, VR), VR, T, false);
+  }
+
+  RegionBindings B = GetRegionBindings(store);
+  const SVal *V = lookup(B, R, BindingKey::Direct);
+
+  // Check if the region has a binding.
+  if (V)
+    return *V;
+
+  // The location does not have a bound value.  This means that it has
+  // the value it had upon its creation and/or entry to the analyzed
+  // function/method.  These are either symbolic values or 'undefined'.
+  if (R->hasStackNonParametersStorage()) {
+    // All stack variables are considered to have undefined values
+    // upon creation.  All heap allocated blocks are considered to
+    // have undefined values as well unless they are explicitly bound
+    // to specific values.
+    return UndefinedVal();
+  }
+
+  // All other values are symbolic.
+  return svalBuilder.getRegionValueSymbolVal(R);
+}
+
+std::pair<Store, const MemRegion *>
+RegionStoreManager::GetLazyBinding(RegionBindings B, const MemRegion *R,
+                                   const MemRegion *originalRegion) {
+  
+  if (originalRegion != R) {
+    if (Optional<SVal> OV = getDefaultBinding(B, R)) {
+      if (const nonloc::LazyCompoundVal *V =
+          dyn_cast<nonloc::LazyCompoundVal>(OV.getPointer()))
+        return std::make_pair(V->getStore(), V->getRegion());
+    }
+  }
+  
+  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
+    const std::pair<Store, const MemRegion *> &X =
+      GetLazyBinding(B, ER->getSuperRegion(), originalRegion);
+
+    if (X.second)
+      return std::make_pair(X.first,
+                            MRMgr.getElementRegionWithSuper(ER, X.second));
+  }
+  else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
+    const std::pair<Store, const MemRegion *> &X =
+      GetLazyBinding(B, FR->getSuperRegion(), originalRegion);
+
+    if (X.second)
+      return std::make_pair(X.first,
+                            MRMgr.getFieldRegionWithSuper(FR, X.second));
+  }
+  // C++ base object region is another kind of region that we should blast
+  // through to look for lazy compound value. It is like a field region.
+  else if (const CXXBaseObjectRegion *baseReg = 
+                            dyn_cast<CXXBaseObjectRegion>(R)) {
+    const std::pair<Store, const MemRegion *> &X =
+      GetLazyBinding(B, baseReg->getSuperRegion(), originalRegion);
+    
+    if (X.second)
+      return std::make_pair(X.first,
+                     MRMgr.getCXXBaseObjectRegionWithSuper(baseReg, X.second));
+  }
+
+  // The NULL MemRegion indicates an non-existent lazy binding. A NULL Store is
+  // possible for a valid lazy binding.
+  return std::make_pair((Store) 0, (const MemRegion *) 0);
+}
+
+SVal RegionStoreManager::getBindingForElement(Store store,
+                                         const ElementRegion* R) {
+  // Check if the region has a binding.
+  RegionBindings B = GetRegionBindings(store);
+  if (const Optional<SVal> &V = getDirectBinding(B, R))
+    return *V;
+
+  const MemRegion* superR = R->getSuperRegion();
+
+  // Check if the region is an element region of a string literal.
+  if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) {
+    // FIXME: Handle loads from strings where the literal is treated as
+    // an integer, e.g., *((unsigned int*)"hello")
+    QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType();
+    if (T != Ctx.getCanonicalType(R->getElementType()))
+      return UnknownVal();
+
+    const StringLiteral *Str = StrR->getStringLiteral();
+    SVal Idx = R->getIndex();
+    if (nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(&Idx)) {
+      int64_t i = CI->getValue().getSExtValue();
+      // Abort on string underrun.  This can be possible by arbitrary
+      // clients of getBindingForElement().
+      if (i < 0)
+        return UndefinedVal();
+      int64_t length = Str->getLength();
+      // Technically, only i == length is guaranteed to be null.
+      // However, such overflows should be caught before reaching this point;
+      // the only time such an access would be made is if a string literal was
+      // used to initialize a larger array.
+      char c = (i >= length) ? '\0' : Str->getCodeUnit(i);
+      return svalBuilder.makeIntVal(c, T);
+    }
+  }
+  
+  // Check for loads from a code text region.  For such loads, just give up.
+  if (isa<CodeTextRegion>(superR))
+    return UnknownVal();
+
+  // Handle the case where we are indexing into a larger scalar object.
+  // For example, this handles:
+  //   int x = ...
+  //   char *y = &x;
+  //   return *y;
+  // FIXME: This is a hack, and doesn't do anything really intelligent yet.
+  const RegionRawOffset &O = R->getAsArrayOffset();
+  
+  // If we cannot reason about the offset, return an unknown value.
+  if (!O.getRegion())
+    return UnknownVal();
+  
+  if (const TypedValueRegion *baseR = 
+        dyn_cast_or_null<TypedValueRegion>(O.getRegion())) {
+    QualType baseT = baseR->getValueType();
+    if (baseT->isScalarType()) {
+      QualType elemT = R->getElementType();
+      if (elemT->isScalarType()) {
+        if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) {
+          if (const Optional<SVal> &V = getDirectBinding(B, superR)) {
+            if (SymbolRef parentSym = V->getAsSymbol())
+              return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
+
+            if (V->isUnknownOrUndef())
+              return *V;
+            // Other cases: give up.  We are indexing into a larger object
+            // that has some value, but we don't know how to handle that yet.
+            return UnknownVal();
+          }
+        }
+      }
+    }
+  }
+  return getBindingForFieldOrElementCommon(store, R, R->getElementType(),
+                                           superR);
+}
+
+SVal RegionStoreManager::getBindingForField(Store store,
+                                       const FieldRegion* R) {
+
+  // Check if the region has a binding.
+  RegionBindings B = GetRegionBindings(store);
+  if (const Optional<SVal> &V = getDirectBinding(B, R))
+    return *V;
+
+  QualType Ty = R->getValueType();
+  return getBindingForFieldOrElementCommon(store, R, Ty, R->getSuperRegion());
+}
+
+Optional<SVal>
+RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindings B,
+                                                     const MemRegion *superR,
+                                                     const TypedValueRegion *R,
+                                                     QualType Ty) {
+
+  if (const Optional<SVal> &D = getDefaultBinding(B, superR)) {
+    const SVal &val = D.getValue();
+    if (SymbolRef parentSym = val.getAsSymbol())
+      return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
+
+    if (val.isZeroConstant())
+      return svalBuilder.makeZeroVal(Ty);
+
+    if (val.isUnknownOrUndef())
+      return val;
+
+    // Lazy bindings are handled later.
+    if (isa<nonloc::LazyCompoundVal>(val))
+      return Optional<SVal>();
+
+    llvm_unreachable("Unknown default value");
+  }
+
+  return Optional<SVal>();
+}
+
+SVal RegionStoreManager::getLazyBinding(const MemRegion *lazyBindingRegion,
+                                             Store lazyBindingStore) {
+  if (const ElementRegion *ER = dyn_cast<ElementRegion>(lazyBindingRegion))
+    return getBindingForElement(lazyBindingStore, ER);
+  
+  return getBindingForField(lazyBindingStore,
+                            cast<FieldRegion>(lazyBindingRegion));
+}
+                                        
+SVal RegionStoreManager::getBindingForFieldOrElementCommon(Store store,
+                                                      const TypedValueRegion *R,
+                                                      QualType Ty,
+                                                      const MemRegion *superR) {
+
+  // At this point we have already checked in either getBindingForElement or
+  // getBindingForField if 'R' has a direct binding.
+  RegionBindings B = GetRegionBindings(store);
+  
+  // Record whether or not we see a symbolic index.  That can completely
+  // be out of scope of our lookup.
+  bool hasSymbolicIndex = false;
+
+  while (superR) {
+    if (const Optional<SVal> &D =
+        getBindingForDerivedDefaultValue(B, superR, R, Ty))
+      return *D;
+
+    if (const ElementRegion *ER = dyn_cast<ElementRegion>(superR)) {
+      NonLoc index = ER->getIndex();
+      if (!index.isConstant())
+        hasSymbolicIndex = true;
+    }
+    
+    // If our super region is a field or element itself, walk up the region
+    // hierarchy to see if there is a default value installed in an ancestor.
+    if (const SubRegion *SR = dyn_cast<SubRegion>(superR)) {
+      superR = SR->getSuperRegion();
+      continue;
+    }
+    break;
+  }
+
+  // Lazy binding?
+  Store lazyBindingStore = NULL;
+  const MemRegion *lazyBindingRegion = NULL;
+  llvm::tie(lazyBindingStore, lazyBindingRegion) = GetLazyBinding(B, R, R);
+
+  if (lazyBindingRegion)
+    return getLazyBinding(lazyBindingRegion, lazyBindingStore);
+
+  if (R->hasStackNonParametersStorage()) {
+    if (isa<ElementRegion>(R)) {
+      // Currently we don't reason specially about Clang-style vectors.  Check
+      // if superR is a vector and if so return Unknown.
+      if (const TypedValueRegion *typedSuperR = 
+            dyn_cast<TypedValueRegion>(superR)) {
+        if (typedSuperR->getValueType()->isVectorType())
+          return UnknownVal();
+      }
+    }
+
+    // FIXME: We also need to take ElementRegions with symbolic indexes into
+    // account.  This case handles both directly accessing an ElementRegion
+    // with a symbolic offset, but also fields within an element with
+    // a symbolic offset.
+    if (hasSymbolicIndex)
+      return UnknownVal();
+    
+    return UndefinedVal();
+  }
+
+  // All other values are symbolic.
+  return svalBuilder.getRegionValueSymbolVal(R);
+}
+
+SVal RegionStoreManager::getBindingForObjCIvar(Store store,
+                                               const ObjCIvarRegion* R) {
+
+    // Check if the region has a binding.
+  RegionBindings B = GetRegionBindings(store);
+
+  if (const Optional<SVal> &V = getDirectBinding(B, R))
+    return *V;
+
+  const MemRegion *superR = R->getSuperRegion();
+
+  // Check if the super region has a default binding.
+  if (const Optional<SVal> &V = getDefaultBinding(B, superR)) {
+    if (SymbolRef parentSym = V->getAsSymbol())
+      return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
+
+    // Other cases: give up.
+    return UnknownVal();
+  }
+
+  return getBindingForLazySymbol(R);
+}
+
+SVal RegionStoreManager::getBindingForVar(Store store, const VarRegion *R) {
+
+  // Check if the region has a binding.
+  RegionBindings B = GetRegionBindings(store);
+
+  if (const Optional<SVal> &V = getDirectBinding(B, R))
+    return *V;
+
+  // Lazily derive a value for the VarRegion.
+  const VarDecl *VD = R->getDecl();
+  QualType T = VD->getType();
+  const MemSpaceRegion *MS = R->getMemorySpace();
+
+  if (isa<UnknownSpaceRegion>(MS) ||
+      isa<StackArgumentsSpaceRegion>(MS))
+    return svalBuilder.getRegionValueSymbolVal(R);
+
+  if (isa<GlobalsSpaceRegion>(MS)) {
+    if (isa<NonStaticGlobalSpaceRegion>(MS)) {
+      // Is 'VD' declared constant?  If so, retrieve the constant value.
+      QualType CT = Ctx.getCanonicalType(T);
+      if (CT.isConstQualified()) {
+        const Expr *Init = VD->getInit();
+        // Do the null check first, as we want to call 'IgnoreParenCasts'.
+        if (Init)
+          if (const IntegerLiteral *IL =
+              dyn_cast<IntegerLiteral>(Init->IgnoreParenCasts())) {
+            const nonloc::ConcreteInt &V = svalBuilder.makeIntVal(IL);
+            return svalBuilder.evalCast(V, Init->getType(), IL->getType());
+          }
+      }
+
+      if (const Optional<SVal> &V
+            = getBindingForDerivedDefaultValue(B, MS, R, CT))
+        return V.getValue();
+
+      return svalBuilder.getRegionValueSymbolVal(R);
+    }
+
+    if (T->isIntegerType())
+      return svalBuilder.makeIntVal(0, T);
+    if (T->isPointerType())
+      return svalBuilder.makeNull();
+
+    return UnknownVal();
+  }
+
+  return UndefinedVal();
+}
+
+SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
+  // All other values are symbolic.
+  return svalBuilder.getRegionValueSymbolVal(R);
+}
+
+SVal RegionStoreManager::getBindingForStruct(Store store, 
+                                        const TypedValueRegion* R) {
+  assert(R->getValueType()->isStructureOrClassType());
+  return svalBuilder.makeLazyCompoundVal(StoreRef(store, *this), R);
+}
+
+SVal RegionStoreManager::getBindingForArray(Store store, 
+                                       const TypedValueRegion * R) {
+  assert(Ctx.getAsConstantArrayType(R->getValueType()));
+  return svalBuilder.makeLazyCompoundVal(StoreRef(store, *this), R);
+}
+
+bool RegionStoreManager::includedInBindings(Store store,
+                                            const MemRegion *region) const {
+  RegionBindings B = GetRegionBindings(store);
+  region = region->getBaseRegion();
+  
+  for (RegionBindings::iterator it = B.begin(), ei = B.end(); it != ei; ++it) {
+    const BindingKey &K = it.getKey();
+    if (region == K.getRegion())
+      return true;
+    const SVal &D = it.getData();
+    if (const MemRegion *r = D.getAsRegion())
+      if (r == region)
+        return true;
+  }
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// Binding values to regions.
+//===----------------------------------------------------------------------===//
+
+StoreRef RegionStoreManager::Remove(Store store, Loc L) {
+  if (isa<loc::MemRegionVal>(L))
+    if (const MemRegion* R = cast<loc::MemRegionVal>(L).getRegion())
+      return StoreRef(removeBinding(GetRegionBindings(store),
+                                    R).getRootWithoutRetain(),
+                      *this);
+
+  return StoreRef(store, *this);
+}
+
+StoreRef RegionStoreManager::Bind(Store store, Loc L, SVal V) {
+  if (isa<loc::ConcreteInt>(L))
+    return StoreRef(store, *this);
+
+  // If we get here, the location should be a region.
+  const MemRegion *R = cast<loc::MemRegionVal>(L).getRegion();
+
+  // Check if the region is a struct region.
+  if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R))
+    if (TR->getValueType()->isStructureOrClassType())
+      return BindStruct(store, TR, V);
+
+  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
+    if (ER->getIndex().isZeroConstant()) {
+      if (const TypedValueRegion *superR =
+            dyn_cast<TypedValueRegion>(ER->getSuperRegion())) {
+        QualType superTy = superR->getValueType();
+        // For now, just invalidate the fields of the struct/union/class.
+        // This is for test rdar_test_7185607 in misc-ps-region-store.m.
+        // FIXME: Precisely handle the fields of the record.
+        if (superTy->isStructureOrClassType())
+          return KillStruct(store, superR, UnknownVal());
+      }
+    }
+  }
+  else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
+    // Binding directly to a symbolic region should be treated as binding
+    // to element 0.
+    QualType T = SR->getSymbol()->getType(Ctx);
+
+    // FIXME: Is this the right way to handle symbols that are references?
+    if (const PointerType *PT = T->getAs<PointerType>())
+      T = PT->getPointeeType();
+    else
+      T = T->getAs<ReferenceType>()->getPointeeType();
+
+    R = GetElementZeroRegion(SR, T);
+  }
+
+  // Perform the binding.
+  RegionBindings B = GetRegionBindings(store);
+  return StoreRef(addBinding(B, R, BindingKey::Direct,
+                             V).getRootWithoutRetain(), *this);
+}
+
+StoreRef RegionStoreManager::BindDecl(Store store, const VarRegion *VR,
+                                      SVal InitVal) {
+
+  QualType T = VR->getDecl()->getType();
+
+  if (T->isArrayType())
+    return BindArray(store, VR, InitVal);
+  if (T->isStructureOrClassType())
+    return BindStruct(store, VR, InitVal);
+
+  return Bind(store, svalBuilder.makeLoc(VR), InitVal);
+}
+
+// FIXME: this method should be merged into Bind().
+StoreRef RegionStoreManager::BindCompoundLiteral(Store store,
+                                                 const CompoundLiteralExpr *CL,
+                                                 const LocationContext *LC,
+                                                 SVal V) {
+  return Bind(store, loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)),
+              V);
+}
+
+StoreRef RegionStoreManager::setImplicitDefaultValue(Store store,
+                                                     const MemRegion *R,
+                                                     QualType T) {
+  RegionBindings B = GetRegionBindings(store);
+  SVal V;
+
+  if (Loc::isLocType(T))
+    V = svalBuilder.makeNull();
+  else if (T->isIntegerType())
+    V = svalBuilder.makeZeroVal(T);
+  else if (T->isStructureOrClassType() || T->isArrayType()) {
+    // Set the default value to a zero constant when it is a structure
+    // or array.  The type doesn't really matter.
+    V = svalBuilder.makeZeroVal(Ctx.IntTy);
+  }
+  else {
+    // We can't represent values of this type, but we still need to set a value
+    // to record that the region has been initialized.
+    // If this assertion ever fires, a new case should be added above -- we
+    // should know how to default-initialize any value we can symbolicate.
+    assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
+    V = UnknownVal();
+  }
+
+  return StoreRef(addBinding(B, R, BindingKey::Default,
+                             V).getRootWithoutRetain(), *this);
+}
+
+StoreRef RegionStoreManager::BindArray(Store store, const TypedValueRegion* R,
+                                       SVal Init) {
+
+  const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType()));
+  QualType ElementTy = AT->getElementType();
+  Optional<uint64_t> Size;
+
+  if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT))
+    Size = CAT->getSize().getZExtValue();
+
+  // Check if the init expr is a string literal.
+  if (loc::MemRegionVal *MRV = dyn_cast<loc::MemRegionVal>(&Init)) {
+    const StringRegion *S = cast<StringRegion>(MRV->getRegion());
+
+    // Treat the string as a lazy compound value.
+    nonloc::LazyCompoundVal LCV =
+      cast<nonloc::LazyCompoundVal>(svalBuilder.
+                                makeLazyCompoundVal(StoreRef(store, *this), S));
+    return CopyLazyBindings(LCV, store, R);
+  }
+
+  // Handle lazy compound values.
+  if (nonloc::LazyCompoundVal *LCV = dyn_cast<nonloc::LazyCompoundVal>(&Init))
+    return CopyLazyBindings(*LCV, store, R);
+
+  // Remaining case: explicit compound values.
+
+  if (Init.isUnknown())
+    return setImplicitDefaultValue(store, R, ElementTy);
+
+  nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(Init);
+  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
+  uint64_t i = 0;
+
+  StoreRef newStore(store, *this);
+  for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) {
+    // The init list might be shorter than the array length.
+    if (VI == VE)
+      break;
+
+    const NonLoc &Idx = svalBuilder.makeArrayIndex(i);
+    const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx);
+
+    if (ElementTy->isStructureOrClassType())
+      newStore = BindStruct(newStore.getStore(), ER, *VI);
+    else if (ElementTy->isArrayType())
+      newStore = BindArray(newStore.getStore(), ER, *VI);
+    else
+      newStore = Bind(newStore.getStore(), svalBuilder.makeLoc(ER), *VI);
+  }
+
+  // If the init list is shorter than the array length, set the
+  // array default value.
+  if (Size.hasValue() && i < Size.getValue())
+    newStore = setImplicitDefaultValue(newStore.getStore(), R, ElementTy);
+
+  return newStore;
+}
+
+StoreRef RegionStoreManager::BindStruct(Store store, const TypedValueRegion* R,
+                                        SVal V) {
+
+  if (!Features.supportsFields())
+    return StoreRef(store, *this);
+
+  QualType T = R->getValueType();
+  assert(T->isStructureOrClassType());
+
+  const RecordType* RT = T->getAs<RecordType>();
+  RecordDecl *RD = RT->getDecl();
+
+  if (!RD->isCompleteDefinition())
+    return StoreRef(store, *this);
+
+  // Handle lazy compound values.
+  if (const nonloc::LazyCompoundVal *LCV=dyn_cast<nonloc::LazyCompoundVal>(&V))
+    return CopyLazyBindings(*LCV, store, R);
+
+  // We may get non-CompoundVal accidentally due to imprecise cast logic or
+  // that we are binding symbolic struct value. Kill the field values, and if
+  // the value is symbolic go and bind it as a "default" binding.
+  if (V.isUnknown() || !isa<nonloc::CompoundVal>(V)) {
+    SVal SV = isa<nonloc::SymbolVal>(V) ? V : UnknownVal();
+    return KillStruct(store, R, SV);
+  }
+
+  nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(V);
+  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
+
+  RecordDecl::field_iterator FI, FE;
+  StoreRef newStore(store, *this);
+  
+  for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
+
+    if (VI == VE)
+      break;
+
+    // Skip any unnamed bitfields to stay in sync with the initializers.
+    if ((*FI)->isUnnamedBitfield())
+      continue;
+
+    QualType FTy = (*FI)->getType();
+    const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R);
+
+    if (FTy->isArrayType())
+      newStore = BindArray(newStore.getStore(), FR, *VI);
+    else if (FTy->isStructureOrClassType())
+      newStore = BindStruct(newStore.getStore(), FR, *VI);
+    else
+      newStore = Bind(newStore.getStore(), svalBuilder.makeLoc(FR), *VI);
+    ++VI;
+  }
+
+  // There may be fewer values in the initialize list than the fields of struct.
+  if (FI != FE) {
+    RegionBindings B = GetRegionBindings(newStore.getStore());
+    B = addBinding(B, R, BindingKey::Default, svalBuilder.makeIntVal(0, false));
+    newStore = StoreRef(B.getRootWithoutRetain(), *this);
+  }
+
+  return newStore;
+}
+
+StoreRef RegionStoreManager::KillStruct(Store store, const TypedRegion* R,
+                                     SVal DefaultVal) {
+  BindingKey key = BindingKey::Make(R, BindingKey::Default);
+  
+  // The BindingKey may be "invalid" if we cannot handle the region binding
+  // explicitly.  One example is something like array[index], where index
+  // is a symbolic value.  In such cases, we want to invalidate the entire
+  // array, as the index assignment could have been to any element.  In
+  // the case of nested symbolic indices, we need to march up the region
+  // hierarchy untile we reach a region whose binding we can reason about.
+  const SubRegion *subReg = R;
+
+  while (!key.isValid()) {
+    if (const SubRegion *tmp = dyn_cast<SubRegion>(subReg->getSuperRegion())) {
+      subReg = tmp;
+      key = BindingKey::Make(tmp, BindingKey::Default);
+    }
+    else
+      break;
+  }                                 
+
+  // Remove the old bindings, using 'subReg' as the root of all regions
+  // we will invalidate.
+  RegionBindings B = GetRegionBindings(store);
+  OwningPtr<RegionStoreSubRegionMap>
+    SubRegions(getRegionStoreSubRegionMap(store));
+  RemoveSubRegionBindings(B, subReg, *SubRegions);
+
+  // Set the default value of the struct region to "unknown".
+  if (!key.isValid())
+    return StoreRef(B.getRootWithoutRetain(), *this);
+  
+  return StoreRef(addBinding(B, key, DefaultVal).getRootWithoutRetain(), *this);
+}
+
+StoreRef RegionStoreManager::CopyLazyBindings(nonloc::LazyCompoundVal V,
+                                              Store store,
+                                              const TypedRegion *R) {
+
+  // Nuke the old bindings stemming from R.
+  RegionBindings B = GetRegionBindings(store);
+
+  OwningPtr<RegionStoreSubRegionMap>
+    SubRegions(getRegionStoreSubRegionMap(store));
+
+  // B and DVM are updated after the call to RemoveSubRegionBindings.
+  RemoveSubRegionBindings(B, R, *SubRegions.get());
+
+  // Now copy the bindings.  This amounts to just binding 'V' to 'R'.  This
+  // results in a zero-copy algorithm.
+  return StoreRef(addBinding(B, R, BindingKey::Default,
+                             V).getRootWithoutRetain(), *this);
+}
+
+//===----------------------------------------------------------------------===//
+// "Raw" retrievals and bindings.
+//===----------------------------------------------------------------------===//
+
+
+RegionBindings RegionStoreManager::addBinding(RegionBindings B, BindingKey K,
+                                              SVal V) {
+  if (!K.isValid())
+    return B;
+  return RBFactory.add(B, K, V);
+}
+
+RegionBindings RegionStoreManager::addBinding(RegionBindings B,
+                                              const MemRegion *R,
+                                              BindingKey::Kind k, SVal V) {
+  return addBinding(B, BindingKey::Make(R, k), V);
+}
+
+const SVal *RegionStoreManager::lookup(RegionBindings B, BindingKey K) {
+  if (!K.isValid())
+    return NULL;
+  return B.lookup(K);
+}
+
+const SVal *RegionStoreManager::lookup(RegionBindings B,
+                                       const MemRegion *R,
+                                       BindingKey::Kind k) {
+  return lookup(B, BindingKey::Make(R, k));
+}
+
+RegionBindings RegionStoreManager::removeBinding(RegionBindings B,
+                                                 BindingKey K) {
+  if (!K.isValid())
+    return B;
+  return RBFactory.remove(B, K);
+}
+
+RegionBindings RegionStoreManager::removeBinding(RegionBindings B,
+                                                 const MemRegion *R,
+                                                BindingKey::Kind k){
+  return removeBinding(B, BindingKey::Make(R, k));
+}
+
+//===----------------------------------------------------------------------===//
+// State pruning.
+//===----------------------------------------------------------------------===//
+
+namespace {
+class removeDeadBindingsWorker :
+  public ClusterAnalysis<removeDeadBindingsWorker> {
+  SmallVector<const SymbolicRegion*, 12> Postponed;
+  SymbolReaper &SymReaper;
+  const StackFrameContext *CurrentLCtx;
+
+public:
+  removeDeadBindingsWorker(RegionStoreManager &rm,
+                           ProgramStateManager &stateMgr,
+                           RegionBindings b, SymbolReaper &symReaper,
+                           const StackFrameContext *LCtx)
+    : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b,
+                                                /* includeGlobals = */ false),
+      SymReaper(symReaper), CurrentLCtx(LCtx) {}
+
+  // Called by ClusterAnalysis.
+  void VisitAddedToCluster(const MemRegion *baseR, RegionCluster &C);
+  void VisitCluster(const MemRegion *baseR, BindingKey *I, BindingKey *E);
+
+  void VisitBindingKey(BindingKey K);
+  bool UpdatePostponed();
+  void VisitBinding(SVal V);
+};
+}
+
+void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
+                                                   RegionCluster &C) {
+
+  if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) {
+    if (SymReaper.isLive(VR))
+      AddToWorkList(baseR, C);
+
+    return;
+  }
+
+  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) {
+    if (SymReaper.isLive(SR->getSymbol()))
+      AddToWorkList(SR, C);
+    else
+      Postponed.push_back(SR);
+
+    return;
+  }
+
+  if (isa<NonStaticGlobalSpaceRegion>(baseR)) {
+    AddToWorkList(baseR, C);
+    return;
+  }
+
+  // CXXThisRegion in the current or parent location context is live.
+  if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) {
+    const StackArgumentsSpaceRegion *StackReg =
+      cast<StackArgumentsSpaceRegion>(TR->getSuperRegion());
+    const StackFrameContext *RegCtx = StackReg->getStackFrame();
+    if (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))
+      AddToWorkList(TR, C);
+  }
+}
+
+void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
+                                            BindingKey *I, BindingKey *E) {
+  for ( ; I != E; ++I)
+    VisitBindingKey(*I);
+}
+
+void removeDeadBindingsWorker::VisitBinding(SVal V) {
+  // Is it a LazyCompoundVal?  All referenced regions are live as well.
+  if (const nonloc::LazyCompoundVal *LCS =
+      dyn_cast<nonloc::LazyCompoundVal>(&V)) {
+
+    const MemRegion *LazyR = LCS->getRegion();
+    RegionBindings B = RegionStoreManager::GetRegionBindings(LCS->getStore());
+    for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){
+      const SubRegion *baseR = dyn_cast<SubRegion>(RI.getKey().getRegion());
+      if (baseR && baseR->isSubRegionOf(LazyR))
+        VisitBinding(RI.getData());
+    }
+    return;
+  }
+
+  // If V is a region, then add it to the worklist.
+  if (const MemRegion *R = V.getAsRegion())
+    AddToWorkList(R);
+
+  // Update the set of live symbols.
+  for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end();
+       SI!=SE; ++SI)
+    SymReaper.markLive(*SI);
+}
+
+void removeDeadBindingsWorker::VisitBindingKey(BindingKey K) {
+  const MemRegion *R = K.getRegion();
+
+  // Mark this region "live" by adding it to the worklist.  This will cause
+  // use to visit all regions in the cluster (if we haven't visited them
+  // already).
+  if (AddToWorkList(R)) {
+    // Mark the symbol for any live SymbolicRegion as "live".  This means we
+    // should continue to track that symbol.
+    if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(R))
+      SymReaper.markLive(SymR->getSymbol());
+
+    // For BlockDataRegions, enqueue the VarRegions for variables marked
+    // with __block (passed-by-reference).
+    // via BlockDeclRefExprs.
+    if (const BlockDataRegion *BD = dyn_cast<BlockDataRegion>(R)) {
+      for (BlockDataRegion::referenced_vars_iterator
+           RI = BD->referenced_vars_begin(), RE = BD->referenced_vars_end();
+           RI != RE; ++RI) {
+        if ((*RI)->getDecl()->getAttr<BlocksAttr>())
+          AddToWorkList(*RI);
+      }
+
+      // No possible data bindings on a BlockDataRegion.
+      return;
+    }
+  }
+
+  // Visit the data binding for K.
+  if (const SVal *V = RM.lookup(B, K))
+    VisitBinding(*V);
+}
+
+bool removeDeadBindingsWorker::UpdatePostponed() {
+  // See if any postponed SymbolicRegions are actually live now, after
+  // having done a scan.
+  bool changed = false;
+
+  for (SmallVectorImpl<const SymbolicRegion*>::iterator
+        I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) {
+    if (const SymbolicRegion *SR = cast_or_null<SymbolicRegion>(*I)) {
+      if (SymReaper.isLive(SR->getSymbol())) {
+        changed |= AddToWorkList(SR);
+        *I = NULL;
+      }
+    }
+  }
+
+  return changed;
+}
+
+StoreRef RegionStoreManager::removeDeadBindings(Store store,
+                                                const StackFrameContext *LCtx,
+                                                SymbolReaper& SymReaper) {
+  RegionBindings B = GetRegionBindings(store);
+  removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
+  W.GenerateClusters();
+
+  // Enqueue the region roots onto the worklist.
+  for (SymbolReaper::region_iterator I = SymReaper.region_begin(),
+       E = SymReaper.region_end(); I != E; ++I) {
+    W.AddToWorkList(*I);
+  }
+
+  do W.RunWorkList(); while (W.UpdatePostponed());
+
+  // We have now scanned the store, marking reachable regions and symbols
+  // as live.  We now remove all the regions that are dead from the store
+  // as well as update DSymbols with the set symbols that are now dead.
+  for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) {
+    const BindingKey &K = I.getKey();
+
+    // If the cluster has been visited, we know the region has been marked.
+    if (W.isVisited(K.getRegion()))
+      continue;
+
+    // Remove the dead entry.
+    B = removeBinding(B, K);
+
+    // Mark all non-live symbols that this binding references as dead.
+    if (const SymbolicRegion* SymR = dyn_cast<SymbolicRegion>(K.getRegion()))
+      SymReaper.maybeDead(SymR->getSymbol());
+
+    SVal X = I.getData();
+    SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end();
+    for (; SI != SE; ++SI)
+      SymReaper.maybeDead(*SI);
+  }
+
+  return StoreRef(B.getRootWithoutRetain(), *this);
+}
+
+
+StoreRef RegionStoreManager::enterStackFrame(ProgramStateRef state,
+                                             const LocationContext *callerCtx,
+                                             const StackFrameContext *calleeCtx)
+{
+  FunctionDecl const *FD = cast<FunctionDecl>(calleeCtx->getDecl());
+  FunctionDecl::param_const_iterator PI = FD->param_begin(), 
+                                     PE = FD->param_end();
+  StoreRef store = StoreRef(state->getStore(), *this);
+
+  if (CallExpr const *CE = dyn_cast<CallExpr>(calleeCtx->getCallSite())) {
+    CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end();
+
+    // Copy the arg expression value to the arg variables.  We check that
+    // PI != PE because the actual number of arguments may be different than
+    // the function declaration.
+    for (; AI != AE && PI != PE; ++AI, ++PI) {
+      SVal ArgVal = state->getSVal(*AI, callerCtx);
+      store = Bind(store.getStore(),
+                   svalBuilder.makeLoc(MRMgr.getVarRegion(*PI, calleeCtx)),
+                   ArgVal);
+    }
+  } else if (const CXXConstructExpr *CE =
+               dyn_cast<CXXConstructExpr>(calleeCtx->getCallSite())) {
+    CXXConstructExpr::const_arg_iterator AI = CE->arg_begin(),
+      AE = CE->arg_end();
+
+    // Copy the arg expression value to the arg variables.
+    for (; AI != AE; ++AI, ++PI) {
+      SVal ArgVal = state->getSVal(*AI, callerCtx);
+      store = Bind(store.getStore(),
+                   svalBuilder.makeLoc(MRMgr.getVarRegion(*PI, calleeCtx)),
+                   ArgVal);
+    }
+  } else
+    assert(isa<CXXDestructorDecl>(calleeCtx->getDecl()));
+
+  return store;
+}
+
+//===----------------------------------------------------------------------===//
+// Utility methods.
+//===----------------------------------------------------------------------===//
+
+void RegionStoreManager::print(Store store, raw_ostream &OS,
+                               const char* nl, const char *sep) {
+  RegionBindings B = GetRegionBindings(store);
+  OS << "Store (direct and default bindings):" << nl;
+
+  for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I)
+    OS << ' ' << I.getKey() << " : " << I.getData() << nl;
+}