6 files changed, 24 insertions, 3 deletions
diff --git a/include/clang/Serialization/ASTDeserializationListener.h b/include/clang/Serialization/ASTDeserializationListener.h
index 731148ecf8..ab0d313a5c 100644
--- a/include/clang/Serialization/ASTDeserializationListener.h
+++ b/include/clang/Serialization/ASTDeserializationListener.h
@@ -48,6 +48,9 @@ public:
   /// \brief A macro definition was read from the AST file.
   virtual void MacroDefinitionRead(serialization::PreprocessedEntityID, 
                                    MacroDefinition *MD) { }
+  /// \brief A macro definition that had previously been deserialized 
+  /// (and removed via IdentifierRead) has now been made visible.
+  virtual void MacroVisible(IdentifierInfo *II) { }
   /// \brief A module definition was read from the AST file.
   virtual void ModuleRead(serialization::SubmoduleID ID, Module *Mod) { }
 };
diff --git a/include/clang/Serialization/ASTWriter.h b/include/clang/Serialization/ASTWriter.h
index fd581bc452..8791d83d93 100644
--- a/include/clang/Serialization/ASTWriter.h
+++ b/include/clang/Serialization/ASTWriter.h
@@ -671,6 +671,7 @@ public:
   void SelectorRead(serialization::SelectorID ID, Selector Sel);
   void MacroDefinitionRead(serialization::PreprocessedEntityID ID,
                            MacroDefinition *MD);
+  void MacroVisible(IdentifierInfo *II);
   void ModuleRead(serialization::SubmoduleID ID, Module *Mod);
                     
   // ASTMutationListener implementation.
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 5971011fce..cb2759bd03 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -2487,8 +2487,14 @@ void ASTReader::makeNamesVisible(const HiddenNames &Names) {
   for (unsigned I = 0, N = Names.size(); I != N; ++I) {
     if (Decl *D = Names[I].dyn_cast<Decl *>())
       D->ModulePrivate = false;
-    else
-      Names[I].get<IdentifierInfo *>()->setHasMacroDefinition(true);
+    else {
+      IdentifierInfo *II = Names[I].get<IdentifierInfo *>();
+      if (!II->hasMacroDefinition()) {
+        II->setHasMacroDefinition(true);
+        if (DeserializationListener)
+          DeserializationListener->MacroVisible(II);
+      }
+    }
   }
 }
 
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index 6883dbe329..97c31b07a3 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -1660,8 +1660,9 @@ void ASTWriter::WritePreprocessor(const Preprocessor &PP, bool IsModule) {
   for (Preprocessor::macro_iterator I = PP.macro_begin(Chain == 0), 
                                     E = PP.macro_end(Chain == 0);
        I != E; ++I) {
+    const IdentifierInfo *Name = I->first;
     if (!IsModule || I->second->isPublic()) {
-      MacroDefinitionsSeen.insert(I->first);
+      MacroDefinitionsSeen.insert(Name);
       MacrosToEmit.push_back(std::make_pair(I->first, I->second));
     }
   }
@@ -4262,6 +4263,10 @@ void ASTWriter::MacroDefinitionRead(serialization::PreprocessedEntityID ID,
   MacroDefinitions[MD] = ID;
 }
 
+void ASTWriter::MacroVisible(IdentifierInfo *II) {
+  DeserializedMacroNames.push_back(II);
+}
+
 void ASTWriter::ModuleRead(serialization::SubmoduleID ID, Module *Mod) {
   assert(SubmoduleIDs.find(Mod) == SubmoduleIDs.end());
   SubmoduleIDs[Mod] = ID;
diff --git a/test/Modules/Inputs/redecl-merge-right.h b/test/Modules/Inputs/redecl-merge-right.h
index f0bfd35746..26eed69b91 100644
--- a/test/Modules/Inputs/redecl-merge-right.h
+++ b/test/Modules/Inputs/redecl-merge-right.h
@@ -21,3 +21,7 @@ public:
   void push_back(const T&);
 };
 #endif
+
+int ONE;
+__import_module__ redecl_merge_top.Explicit;
+const int one = ONE;
diff --git a/test/Modules/Inputs/redecl-merge-top-explicit.h b/test/Modules/Inputs/redecl-merge-top-explicit.h
index c8f51589f3..54aab33e6c 100644
--- a/test/Modules/Inputs/redecl-merge-top-explicit.h
+++ b/test/Modules/Inputs/redecl-merge-top-explicit.h
@@ -3,3 +3,5 @@
 int *explicit_func(void);
 
 struct explicit_struct { int member; };
+
+#define ONE 1