Serialize the AST reader's mapping from canonical declarations to the

set of (previously-canonical) declaration IDs to the module file, so
that future AST reader instances that load the module know which
declarations are merged. This is important in the fairly tricky case
where a declaration of an entity, e.g.,

  @class X;

occurs before the import of a module that also declares that
entity. We merge the declarations, and record the fact that the
declaration of X loaded from the module was merged into the (now
canonical) declaration of X that we parsed.

llvm-svn: 147181

1 files changed, 10 insertions, 0 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 2ac1908ee2f..440474b587a 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -2407,6 +2407,16 @@ ASTReader::ReadASTBlock(ModuleFile &F) {
       F.RedeclarationsInfo = (const LocalRedeclarationsInfo *)BlobStart;
       break;
     }
+        
+    case MERGED_DECLARATIONS: {
+      for (unsigned Idx = 0; Idx < Record.size(); /* increment in loop */) {
+        GlobalDeclID CanonID = getGlobalDeclID(F, Record[Idx++]);
+        SmallVectorImpl<GlobalDeclID> &Decls = StoredMergedDecls[CanonID];
+        for (unsigned N = Record[Idx++]; N > 0; --N)
+          Decls.push_back(getGlobalDeclID(F, Record[Idx++]));
+      }
+      break;
+    }
     }
   }
   Error("premature end of bitstream in AST file");