3 files changed, 50 insertions, 2 deletions

diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
index 328ed841ce..f5f6f5d41c 100644
--- a/lib/Frontend/PCHReader.cpp
+++ b/lib/Frontend/PCHReader.cpp
@@ -12,8 +12,10 @@
 //===----------------------------------------------------------------------===//
 #include "clang/Frontend/PCHReader.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/AST/ASTConsumer.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Decl.h"
+#include "clang/AST/DeclGroup.h"
 #include "clang/AST/Type.h"
 #include "clang/Lex/MacroInfo.h"
 #include "clang/Lex/Preprocessor.h"
@@ -663,6 +665,14 @@ PCHReader::PCHReadResult PCHReader::ReadPCHBlock() {
       }
 #endif
       break;
+
+    case pch::EXTERNAL_DEFINITIONS:
+      if (!ExternalDefinitions.empty()) {
+        Error("Duplicate EXTERNAL_DEFINITIONS record in PCH file");
+        return Failure;
+      }
+      ExternalDefinitions.swap(Record);
+      break;
     }
   }
 
@@ -1276,6 +1286,17 @@ bool PCHReader::ReadDeclsVisibleInContext(DeclContext *DC,
   return false;
 }
 
+void PCHReader::StartTranslationUnit(ASTConsumer *Consumer) {
+  if (!Consumer)
+    return;
+
+  for (unsigned I = 0, N = ExternalDefinitions.size(); I != N; ++I) {
+    Decl *D = GetDecl(ExternalDefinitions[I]);
+    DeclGroupRef DG(D);
+    Consumer->HandleTopLevelDecl(DG);
+  }
+}
+
 void PCHReader::PrintStats() {
   std::fprintf(stderr, "*** PCH Statistics:\n");
 
diff --git a/lib/Frontend/PCHWriter.cpp b/lib/Frontend/PCHWriter.cpp
index 738e5c1879..c7bfa0b74e 100644
--- a/lib/Frontend/PCHWriter.cpp
+++ b/lib/Frontend/PCHWriter.cpp
@@ -934,8 +934,29 @@ void PCHWriter::WriteDeclsBlock(ASTContext &Context) {
     W.Code = (pch::DeclCode)0;
     W.Visit(D);
     if (DC) W.VisitDeclContext(DC, LexicalOffset, VisibleOffset);
-    assert(W.Code && "Visitor did not set record code");
+    assert(W.Code && "Unhandled declaration kind while generating PCH");
     S.EmitRecord(W.Code, Record);
+
+    // Note external declarations so that we can add them to a record
+    // in the PCH file later.
+    if (isa<FileScopeAsmDecl>(D))
+      ExternalDefinitions.push_back(ID);
+    else if (VarDecl *Var = dyn_cast<VarDecl>(D)) {
+      if (// Non-static file-scope variables with initializers or that
+          // are tentative definitions.
+          (Var->isFileVarDecl() &&
+           (Var->getInit() || Var->getStorageClass() == VarDecl::None)) ||
+          // Out-of-line definitions of static data members (C++).
+          (Var->getDeclContext()->isRecord() && 
+           !Var->getLexicalDeclContext()->isRecord() && 
+           Var->getStorageClass() == VarDecl::Static))
+        ExternalDefinitions.push_back(ID);
+    } else if (FunctionDecl *Func = dyn_cast<FunctionDecl>(D)) {
+      if (Func->isThisDeclarationADefinition() &&
+          Func->getStorageClass() != FunctionDecl::Static &&
+          !Func->isInline())
+        ExternalDefinitions.push_back(ID);
+    }
   }
 
   // Exit the declarations block
@@ -1013,9 +1034,11 @@ void PCHWriter::WritePCH(ASTContext &Context, const Preprocessor &PP) {
   WritePreprocessor(PP);
   WriteTypesBlock(Context);
   WriteDeclsBlock(Context);
+  WriteIdentifierTable();
   S.EmitRecord(pch::TYPE_OFFSET, TypeOffsets);
   S.EmitRecord(pch::DECL_OFFSET, DeclOffsets);
-  WriteIdentifierTable();
+  if (!ExternalDefinitions.empty())
+    S.EmitRecord(pch::EXTERNAL_DEFINITIONS, ExternalDefinitions);
   S.ExitBlock();
 }
 
diff --git a/lib/Sema/ParseAST.cpp b/lib/Sema/ParseAST.cpp
index 4bcb478e89..bb5acb0ee8 100644
--- a/lib/Sema/ParseAST.cpp
+++ b/lib/Sema/ParseAST.cpp
@@ -14,6 +14,7 @@
 #include <llvm/ADT/OwningPtr.h>
 #include "clang/Sema/ParseAST.h"
 #include "clang/AST/ASTConsumer.h"
+#include "clang/AST/ExternalASTSource.h"
 #include "clang/AST/Stmt.h"
 #include "Sema.h"
 #include "clang/Parse/Parser.h"
@@ -44,6 +45,9 @@ void clang::ParseAST(Preprocessor &PP, ASTConsumer *Consumer,
   
   Consumer->Initialize(Ctx);
   
+  if (Ctx.getExternalSource())
+    Ctx.getExternalSource()->StartTranslationUnit(Consumer);
+
   Parser::DeclGroupPtrTy ADecl;
   
   while (!P.ParseTopLevelDecl(ADecl)) {  // Not end of file.