Index: lib/StaticAnalyzer/Checkers/DanglingInternalBufferChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/DanglingInternalBufferChecker.cpp
+++ lib/StaticAnalyzer/Checkers/DanglingInternalBufferChecker.cpp
@@ -24,10 +24,22 @@
 using namespace clang;
 using namespace ento;
 
-// FIXME: member functions that return a pointer to the container's internal
-// buffer may be called on the object many times, so the object's memory
-// region should have a list of pointer symbols associated with it.
-REGISTER_MAP_WITH_PROGRAMSTATE(RawPtrMap, const MemRegion *, SymbolRef)
+using PtrSet = llvm::ImmutableSet<SymbolRef>;
+
+// Associate container objects with a set of raw pointer symbols.
+REGISTER_MAP_WITH_PROGRAMSTATE(RawPtrMap, const MemRegion *, PtrSet)
+
+namespace clang {
+namespace ento {
+template<> struct ProgramStateTrait<PtrSet>
+  : public ProgramStatePartialTrait<PtrSet> {
+  static void *GDMIndex() {
+    static int Index = 0;
+    return &Index;
+  }
+};
+} // end namespace ento
+} // end namespace clang
 
 namespace {
 
@@ -60,8 +72,8 @@
     // lookup by region.
     bool isSymbolTracked(ProgramStateRef State, SymbolRef Sym) {
       RawPtrMapTy Map = State->get<RawPtrMap>();
-      for (const auto Entry : Map) {
-        if (Entry.second == Sym)
+      for (const auto &Entry : Map) {
+        if (Entry.second.contains(Sym))
           return true;
       }
       return false;
@@ -88,11 +100,11 @@
     return;
 
   SVal Obj = ICall->getCXXThisVal();
-  const auto *TypedR = dyn_cast_or_null<TypedValueRegion>(Obj.getAsRegion());
-  if (!TypedR)
+  const auto *ObjRegion = dyn_cast_or_null<TypedValueRegion>(Obj.getAsRegion());
+  if (!ObjRegion)
     return;
 
-  auto *TypeDecl = TypedR->getValueType()->getAsCXXRecordDecl();
+  auto *TypeDecl = ObjRegion->getValueType()->getAsCXXRecordDecl();
   if (TypeDecl->getName() != "basic_string")
     return;
 
@@ -101,19 +113,30 @@
   if (Call.isCalled(CStrFn) || Call.isCalled(DataFn)) {
     SVal RawPtr = Call.getReturnValue();
     if (!RawPtr.isUnknown()) {
-      State = State->set<RawPtrMap>(TypedR, RawPtr.getAsSymbol());
+      // Start tracking this raw pointer by adding it to the set of symbols
+      // associated with this container object in the program state map.
+      PtrSet::Factory &F = State->getStateManager().get_context<PtrSet>();
+      PtrSet NewSet = F.getEmptySet();
+      if (State->contains<RawPtrMap>(ObjRegion)) {
+        NewSet = *State->get<RawPtrMap>(ObjRegion);
+        if (NewSet.contains(RawPtr.getAsSymbol()))
+          return;
+      }
+      NewSet = F.add(NewSet, RawPtr.getAsSymbol());
+      assert(!NewSet.isEmpty());
+      State = State->set<RawPtrMap>(ObjRegion, NewSet);
       C.addTransition(State);
     }
     return;
   }
 
   if (isa<CXXDestructorCall>(ICall)) {
-    if (State->contains<RawPtrMap>(TypedR)) {
-      const SymbolRef *StrBufferPtr = State->get<RawPtrMap>(TypedR);
-      // FIXME: What if Origin is null?
+    if (const PtrSet *PS = State->get<RawPtrMap>(ObjRegion)) {
+      // Mark all pointer symbols associated with the deleted object released.
       const Expr *Origin = Call.getOriginExpr();
-      State = allocation_state::markReleased(State, *StrBufferPtr, Origin);
-      State = State->remove<RawPtrMap>(TypedR);
+      for (const auto &Symbol : *PS)
+        State = allocation_state::markReleased(State, Symbol, Origin);
+      State = State->remove<RawPtrMap>(ObjRegion);
       C.addTransition(State);
       return;
     }
@@ -123,15 +146,24 @@
 void DanglingInternalBufferChecker::checkDeadSymbols(SymbolReaper &SymReaper,
                                                      CheckerContext &C) const {
   ProgramStateRef State = C.getState();
+  PtrSet::Factory &F = State->getStateManager().get_context<PtrSet>();
   RawPtrMapTy RPM = State->get<RawPtrMap>();
-  for (const auto Entry : RPM) {
-    if (!SymReaper.isLive(Entry.second))
-      State = State->remove<RawPtrMap>(Entry.first);
+  for (const auto &Entry : RPM) {
     if (!SymReaper.isLiveRegion(Entry.first)) {
-      // Due to incomplete destructor support, some dead regions might still
+      // Due to incomplete destructor support, some dead regions might
       // remain in the program state map. Clean them up.
       State = State->remove<RawPtrMap>(Entry.first);
     }
+    if (const PtrSet *OldSet = State->get<RawPtrMap>(Entry.first)) {
+      PtrSet CleanedUpSet = *OldSet;
+      for (const auto &Symbol : Entry.second) {
+        if (!SymReaper.isLive(Symbol))
+          CleanedUpSet = F.remove(CleanedUpSet, Symbol);
+      }
+      State = CleanedUpSet.isEmpty()
+              ? State->remove<RawPtrMap>(Entry.first)
+              : State->set<RawPtrMap>(Entry.first, CleanedUpSet);
+    }
   }
   C.addTransition(State);
 }
Index: test/Analysis/dangling-internal-buffer.cpp
===================================================================
--- test/Analysis/dangling-internal-buffer.cpp
+++ test/Analysis/dangling-internal-buffer.cpp
@@ -108,6 +108,30 @@
   // expected-note@-1 {{Use of memory after it is freed}}
 }
 
+void multiple_symbols(bool cond) {
+  const char *c1, *d1;
+  {
+    std::string s1;
+    c1 = s1.c_str(); // expected-note {{Pointer to dangling buffer was obtained here}}
+    d1 = s1.data(); // expected-note {{Pointer to dangling buffer was obtained here}}
+    const char *local = s1.c_str();
+    consume(local); // no-warning
+  } // expected-note {{Internal buffer is released because the object was destroyed}}
+  // expected-note@-1 {{Internal buffer is released because the object was destroyed}}
+  std::string s2;
+  const char *c2 = s2.c_str();
+  if (cond) {
+    // expected-note@-1 {{Assuming 'cond' is not equal to 0}}
+    // expected-note@-2 {{Taking true branch}}
+    // expected-note@-3 {{Assuming 'cond' is 0}}
+    // expected-note@-4 {{Taking false branch}}
+    consume(c1); // expected-warning {{Use of memory after it is freed}}
+    // expected-note@-1 {{Use of memory after it is freed}}
+  } else {
+    consume(d1); // expected-warning {{Use of memory after it is freed}}
+  } // expected-note@-1 {{Use of memory after it is freed}}
+}
+
 void deref_after_scope_cstr_ok() {
   const char *c;
   std::string s;