When reading the AST, delay loading of the redeclaration chain to avoid deeply nested calls.

Temporarily set the first (canonical) declaration as the previous one, which is the one that
matters, and mark the real previous DeclID to be loaded & attached later on.

Fixes rdar://8956193.

llvm-svn: 125434

1 files changed, 11 insertions, 3 deletions

diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index b0ed8bc59f8..17ee85ad279 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -862,6 +862,9 @@ void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
   // getCommonPtr() can be used while this is still initializing.
 
   Writer.AddDeclRef(D->getPreviousDeclaration(), Record);
+  if (D->getPreviousDeclaration())
+    Writer.AddDeclRef(D->getFirstDeclaration(), Record);
+
   if (D->getPreviousDeclaration() == 0) {
     // This TemplateDecl owns the CommonPtr; write it.
     assert(D->isCanonicalDecl());
@@ -1075,9 +1078,14 @@ void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
   if (D->RedeclLink.getNext() == D) {
     Record.push_back(NoRedeclaration);
   } else {
-    Record.push_back(D->RedeclLink.NextIsPrevious() ? PointsToPrevious
-                                                    : PointsToLatest);
-    Writer.AddDeclRef(D->RedeclLink.getPointer(), Record);
+    if (D->RedeclLink.NextIsPrevious()) {
+      Record.push_back(PointsToPrevious);
+      Writer.AddDeclRef(D->getPreviousDeclaration(), Record);
+      Writer.AddDeclRef(D->getFirstDeclaration(), Record);
+    } else {
+      Record.push_back(PointsToLatest);
+      Writer.AddDeclRef(D->RedeclLink.getPointer(), Record);
+    }
   }
 
   T *First = D->getFirstDeclaration();