6 files changed, 37 insertions, 17 deletions
diff --git a/include/clang/Sema/ExternalSemaSource.h b/include/clang/Sema/ExternalSemaSource.h
index a45456f3e8..939c9dfabe 100644
--- a/include/clang/Sema/ExternalSemaSource.h
+++ b/include/clang/Sema/ExternalSemaSource.h
@@ -24,6 +24,7 @@ class LookupResult;
 struct ObjCMethodList;
 class Scope;
 class Sema;
+class TypedefNameDecl;
 class VarDecl;
   
 /// \brief An abstract interface that should be implemented by
@@ -96,7 +97,16 @@ public:
   /// introduce the same declarations repeatedly.
   virtual void ReadDelegatingConstructors(
                  SmallVectorImpl<CXXConstructorDecl *> &Decls) {}
-  
+
+  /// \brief Read the set of ext_vector type declarations known to the
+  /// external Sema source.
+  ///
+  /// The external source should append its own ext_vector type declarations to
+  /// the given vector of declarations. Note that this routine may be
+  /// invoked multiple times; the external source should take care not to
+  /// introduce the same declarations repeatedly.
+  virtual void ReadExtVectorDecls(SmallVectorImpl<TypedefNameDecl *> &Decls) {}
+
   // isa/cast/dyn_cast support
   static bool classof(const ExternalASTSource *Source) {
     return Source->SemaSource;
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 12ff22c1b1..520fe8fc94 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -235,10 +235,14 @@ public:
   /// the current full expression.
   SmallVector<CXXTemporary*, 8> ExprTemporaries;
 
+  typedef LazyVector<TypedefNameDecl *, ExternalSemaSource, 
+                     &ExternalSemaSource::ReadExtVectorDecls, 2, 2>
+    ExtVectorDeclsType;
+
   /// ExtVectorDecls - This is a list all the extended vector types. This allows
   /// us to associate a raw vector type with one of the ext_vector type names.
   /// This is only necessary for issuing pretty diagnostics.
-  SmallVector<TypedefNameDecl*, 24> ExtVectorDecls;
+  ExtVectorDeclsType ExtVectorDecls;
 
   /// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
   llvm::OwningPtr<CXXFieldCollector> FieldCollector;
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index a309773095..ec8ed5f5cb 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -1380,6 +1380,8 @@ public:
   virtual void ReadDelegatingConstructors(
                  SmallVectorImpl<CXXConstructorDecl *> &Decls);
 
+  virtual void ReadExtVectorDecls(SmallVectorImpl<TypedefNameDecl *> &Decls);
+
   /// \brief Load a selector from disk, registering its ID if it exists.
   void LoadSelector(Selector Sel);
 
diff --git a/lib/Sema/SemaExprMember.cpp b/lib/Sema/SemaExprMember.cpp
index e5940c667f..cde29f5b4c 100644
--- a/lib/Sema/SemaExprMember.cpp
+++ b/lib/Sema/SemaExprMember.cpp
@@ -337,10 +337,14 @@ CheckExtVectorComponent(Sema &S, QualType baseType, ExprValueKind &VK,
   QualType VT = S.Context.getExtVectorType(vecType->getElementType(), CompSize);
   // Now look up the TypeDefDecl from the vector type. Without this,
   // diagostics look bad. We want extended vector types to appear built-in.
-  for (unsigned i = 0, E = S.ExtVectorDecls.size(); i != E; ++i) {
-    if (S.ExtVectorDecls[i]->getUnderlyingType() == VT)
-      return S.Context.getTypedefType(S.ExtVectorDecls[i]);
+  for (Sema::ExtVectorDeclsType::iterator 
+         I = S.ExtVectorDecls.begin(S.ExternalSource),
+         E = S.ExtVectorDecls.end(); 
+       I != E; ++I) {
+    if ((*I)->getUnderlyingType() == VT)
+      return S.Context.getTypedefType(*I);
   }
+  
   return VT; // should never get here (a typedef type should always be found).
 }
 
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index d39029ac6f..e8ae251e5a 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -4336,12 +4336,6 @@ void ASTReader::InitializeSema(Sema &S) {
     SemaObj->LocallyScopedExternalDecls[D->getDeclName()] = D;
   }
 
-  // If there were any ext_vector type declarations, deserialize them
-  // and add them to Sema's vector of such declarations.
-  for (unsigned I = 0, N = ExtVectorDecls.size(); I != N; ++I)
-    SemaObj->ExtVectorDecls.push_back(
-                             cast<TypedefNameDecl>(GetDecl(ExtVectorDecls[I])));
-
   // FIXME: Do VTable uses and dynamic classes deserialize too much ?
   // Can we cut them down before writing them ?
 
@@ -4582,6 +4576,16 @@ void ASTReader::ReadDelegatingConstructors(
   DelegatingCtorDecls.clear();
 }
 
+void ASTReader::ReadExtVectorDecls(SmallVectorImpl<TypedefNameDecl *> &Decls) {
+  for (unsigned I = 0, N = ExtVectorDecls.size(); I != N; ++I) {
+    TypedefNameDecl *D
+      = dyn_cast_or_null<TypedefNameDecl>(GetDecl(ExtVectorDecls[I]));
+    if (D)
+      Decls.push_back(D);
+  }
+  ExtVectorDecls.clear();
+}
+
 void ASTReader::LoadSelector(Selector Sel) {
   // It would be complicated to avoid reading the methods anyway. So don't.
   ReadMethodPool(Sel);
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index 44cf99fe0b..3cc2dae4fc 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -2852,8 +2852,7 @@ void ASTWriter::WriteASTCore(Sema &SemaRef, MemorizeStatCalls *StatCalls,
 
   // Build a record containing all of the ext_vector declarations.
   RecordData ExtVectorDecls;
-  for (unsigned I = 0, N = SemaRef.ExtVectorDecls.size(); I != N; ++I)
-    AddDeclRef(SemaRef.ExtVectorDecls[I], ExtVectorDecls);
+  AddLazyVectorDecls(*this, SemaRef.ExtVectorDecls, ExtVectorDecls);
 
   // Build a record containing all of the VTable uses information.
   RecordData VTableUses;
@@ -3121,10 +3120,7 @@ void ASTWriter::WriteASTChain(Sema &SemaRef, MemorizeStatCalls *StatCalls,
 
   // Build a record containing all of the ext_vector declarations.
   RecordData ExtVectorDecls;
-  for (unsigned I = 0, N = SemaRef.ExtVectorDecls.size(); I != N; ++I) {
-    if (SemaRef.ExtVectorDecls[I]->getPCHLevel() == 0)
-      AddDeclRef(SemaRef.ExtVectorDecls[I], ExtVectorDecls);
-  }
+  AddLazyVectorDecls(*this, SemaRef.ExtVectorDecls, ExtVectorDecls);
 
   // Build a record containing all of the VTable uses information.
   // We write everything here, because it's too hard to determine whether