diff --git a/lib/Checker/GRBlockCounter.cpp b/lib/Checker/GRBlockCounter.cpp
index 3fa3e1e..cd26060 100644
--- a/lib/Checker/GRBlockCounter.cpp
+++ b/lib/Checker/GRBlockCounter.cpp
@@ -18,7 +18,34 @@
 
 using namespace clang;
 
-typedef llvm::ImmutableMap<unsigned,unsigned> CountMap;
+namespace {
+
+class CountKey {
+  const StackFrameContext *CallSite;
+  unsigned BlockID;
+
+public:
+  CountKey(const StackFrameContext *CS, unsigned ID) 
+    : CallSite(CS), BlockID(ID) {}
+
+  bool operator==(const CountKey &RHS) const {
+    return (CallSite == RHS.CallSite) && (BlockID == RHS.BlockID);
+  }
+
+  bool operator<(const CountKey &RHS) const {
+    return (CallSite == RHS.CallSite) ? (BlockID < RHS.BlockID) 
+                                      : (CallSite < RHS.CallSite);
+  }
+
+  void Profile(llvm::FoldingSetNodeID &ID) const {
+    ID.AddPointer(CallSite);
+    ID.AddInteger(BlockID);
+  }
+};
+
+}
+
+typedef llvm::ImmutableMap<CountKey, unsigned> CountMap;
 
 static inline CountMap GetMap(void* D) {
   return CountMap(static_cast<CountMap::TreeTy*>(D));
@@ -28,9 +55,10 @@
   return *static_cast<CountMap::Factory*>(F);
 }
 
-unsigned GRBlockCounter::getNumVisited(unsigned BlockID) const {
+unsigned GRBlockCounter::getNumVisited(const StackFrameContext *CallSite, 
+                                       unsigned BlockID) const {
   CountMap M = GetMap(Data);
-  CountMap::data_type* T = M.lookup(BlockID);
+  CountMap::data_type* T = M.lookup(CountKey(CallSite, BlockID));
   return T ? *T : 0;
 }
 
@@ -43,9 +71,12 @@
 }
 
 GRBlockCounter
-GRBlockCounter::Factory::IncrementCount(GRBlockCounter BC, unsigned BlockID) {
-  return GRBlockCounter(GetFactory(F).Add(GetMap(BC.Data), BlockID,
-                                        BC.getNumVisited(BlockID)+1).getRoot());
+GRBlockCounter::Factory::IncrementCount(GRBlockCounter BC, 
+                                        const StackFrameContext *CallSite,
+                                        unsigned BlockID) {
+  return GRBlockCounter(GetFactory(F).Add(GetMap(BC.Data), 
+                                          CountKey(CallSite, BlockID),
+                             BC.getNumVisited(CallSite, BlockID)+1).getRoot());
 }
 
 GRBlockCounter