Implement redeclaration merging for namespaces defined in distinct

modules. Teach name lookup into namespaces to search in each of the
merged DeclContexts as well as the (now-primary) DeclContext. This
supports the common case where two different modules put something
into the same namespace.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147778 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 5 deletions

diff --git a/lib/AST/DeclBase.cpp b/lib/AST/DeclBase.cpp
index 0312cfbc4a..6a508dfcbe 100644
--- a/lib/AST/DeclBase.cpp
+++ b/lib/AST/DeclBase.cpp
@@ -45,14 +45,17 @@ void *Decl::AllocateDeserializedDecl(const ASTContext &Context,
                                      unsigned ID,
                                      unsigned Size) {
   // Allocate an extra 8 bytes worth of storage, which ensures that the
-  // resulting pointer will still be 8-byte aligned. At present, we're only
-  // using the latter 4 bytes of this storage.
+  // resulting pointer will still be 8-byte aligned. 
   void *Start = Context.Allocate(Size + 8);
   void *Result = (char*)Start + 8;
   
-  // Store the global declaration ID 
-  unsigned *IDPtr = (unsigned*)Result - 1;
-  *IDPtr = ID;
+  unsigned *PrefixPtr = (unsigned *)Result - 2;
+  
+  // Zero out the first 4 bytes; this is used to store the owning module ID.
+  PrefixPtr[0] = 0;
+  
+  // Store the global declaration ID in the second 4 bytes.
+  PrefixPtr[1] = ID;
   
   return Result;
 }