1 files changed, 24 insertions, 13 deletions
diff --git a/lib/Serialization/ASTWriterDecl.cpp b/lib/Serialization/ASTWriterDecl.cpp
index d7cc850a80..7a4ef63bb3 100644
--- a/lib/Serialization/ASTWriterDecl.cpp
+++ b/lib/Serialization/ASTWriterDecl.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Serialization/ASTWriter.h"
+#include "clang/Serialization/ASTReader.h"
 #include "ASTCommon.h"
 #include "clang/AST/DeclVisitor.h"
 #include "clang/AST/DeclCXX.h"
@@ -1640,6 +1641,20 @@ void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
   RecordData Record;
   ASTDeclWriter W(*this, Context, Record);
 
+  // Determine the ID for this declaration.
+  serialization::DeclID ID;
+  if (D->isFromASTFile())
+    ID = getDeclID(D);
+  else {
+    serialization::DeclID &IDR = DeclIDs[D];
+    if (IDR == 0)
+      IDR = NextDeclID++;
+    
+    ID= IDR;
+  }
+
+  bool isReplacingADecl = ID < FirstDeclID;
+
   // If this declaration is also a DeclContext, write blocks for the
   // declarations that lexically stored inside its context and those
   // declarations that are visible from its context. These blocks
@@ -1649,23 +1664,19 @@ void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
   uint64_t VisibleOffset = 0;
   DeclContext *DC = dyn_cast<DeclContext>(D);
   if (DC) {
+    if (isReplacingADecl) {
+      // It is replacing a decl from a chained PCH; make sure that the
+      // DeclContext is fully loaded.
+      if (DC->hasExternalLexicalStorage())
+        DC->LoadLexicalDeclsFromExternalStorage();
+      if (DC->hasExternalVisibleStorage())
+        Chain->completeVisibleDeclsMap(DC);
+    }
     LexicalOffset = WriteDeclContextLexicalBlock(Context, DC);
     VisibleOffset = WriteDeclContextVisibleBlock(Context, DC);
   }
-
-  // Determine the ID for this declaration.
-  serialization::DeclID ID;
-  if (D->isFromASTFile())
-    ID = getDeclID(D);
-  else {
-    serialization::DeclID &IDR = DeclIDs[D];
-    if (IDR == 0)
-      IDR = NextDeclID++;
-    
-    ID= IDR;
-  }
   
-  if (ID < FirstDeclID) {
+  if (isReplacingADecl) {
     // We're replacing a decl in a previous file.
     ReplacedDecls.push_back(ReplacedDeclInfo(ID, Stream.GetCurrentBitNo(),
                                              D->getLocation()));