[PCH] When we are replacing a decl in a chained PCH that is also a DeclContext,

make sure to fully load its external lexical and visible declarations before
re-writing it.

rdar://10914192

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153254 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 69 insertions, 13 deletions

diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 4c6c9dc524..9436bfb50b 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -4972,6 +4972,51 @@ ASTReader::FindExternalVisibleDeclsByName(const DeclContext *DC,
   return const_cast<DeclContext*>(DC)->lookup(Name);
 }
 
+namespace {
+  /// \brief ModuleFile visitor used to complete the visible decls map of a
+  /// declaration context.
+  class DeclContextVisibleDeclMapVisitor {
+    ASTReader &Reader;
+    DeclContext *DC;
+
+  public:
+    DeclContextVisibleDeclMapVisitor(ASTReader &Reader, DeclContext *DC)
+      : Reader(Reader), DC(DC) { }
+
+    static bool visit(ModuleFile &M, void *UserData) {
+      return static_cast<DeclContextVisibleDeclMapVisitor*>(UserData)->visit(M);
+    }
+
+    bool visit(ModuleFile &M) {
+      // Check whether we have any visible declaration information for
+      // this context in this module.
+      ModuleFile::DeclContextInfosMap::iterator
+        Info = M.DeclContextInfos.find(DC);
+      if (Info == M.DeclContextInfos.end() || 
+          !Info->second.NameLookupTableData)
+        return false;
+      
+      // Look for this name within this module.
+      ASTDeclContextNameLookupTable *LookupTable =
+        (ASTDeclContextNameLookupTable*)Info->second.NameLookupTableData;
+      for (ASTDeclContextNameLookupTable::key_iterator
+             I = LookupTable->key_begin(),
+             E = LookupTable->key_end(); I != E; ++I) {
+        DC->lookup(*I); // Force loading of the visible decls for the decl name.
+      }
+
+      return false;
+    }
+  };
+}
+
+void ASTReader::completeVisibleDeclsMap(DeclContext *DC) {
+  if (!DC->hasExternalVisibleStorage())
+    return;
+  DeclContextVisibleDeclMapVisitor Visitor(*this, DC);
+  ModuleMgr.visit(&DeclContextVisibleDeclMapVisitor::visit, &Visitor);
+}
+
 /// \brief Under non-PCH compilation the consumer receives the objc methods
 /// before receiving the implementation, and codegen depends on this.
 /// We simulate this by deserializing and passing to consumer the methods of the
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()));