Store latest redeclaration for each redeclarable template declaration

This patch adds a Latest field to RedeclarableTemplateDecl's CommonBase
class which is used to store the latest redeclaration.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@109755 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 20 insertions, 0 deletions

diff --git a/lib/AST/DeclTemplate.cpp b/lib/AST/DeclTemplate.cpp
index de17568942..0ca2837627 100644
--- a/lib/AST/DeclTemplate.cpp
+++ b/lib/AST/DeclTemplate.cpp
@@ -94,6 +94,7 @@ RedeclarableTemplateDecl::CommonBase *RedeclarableTemplateDecl::getCommonPtr() {
   if (First->CommonOrPrev.isNull()) {
     CommonBase *CommonPtr = First->newCommon();
     First->CommonOrPrev = CommonPtr;
+    CommonPtr->Latest = First;
   }
   return First->CommonOrPrev.get<CommonBase*>();
 }
@@ -106,6 +107,18 @@ RedeclarableTemplateDecl *RedeclarableTemplateDecl::getCanonicalDeclImpl() {
   return Tmpl;
 }
 
+void RedeclarableTemplateDecl::setPreviousDeclarationImpl(
+                                               RedeclarableTemplateDecl *Prev) {
+  if (Prev) {
+    CommonBase *Common = Prev->getCommonPtr();
+    Prev = Common->Latest;
+    Common->Latest = this;
+    CommonOrPrev = Prev;
+  } else {
+    assert(CommonOrPrev.is<CommonBase*>() && "Cannot reset TemplateDecl Prev");
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // FunctionTemplateDecl Implementation
 //===----------------------------------------------------------------------===//
diff --git a/lib/Frontend/PCHReaderDecl.cpp b/lib/Frontend/PCHReaderDecl.cpp
index 94485d2d8f..03e7e1a093 100644
--- a/lib/Frontend/PCHReaderDecl.cpp
+++ b/lib/Frontend/PCHReaderDecl.cpp
@@ -915,6 +915,11 @@ void PCHDeclReader::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
       if (Record[Idx++])
         D->setMemberSpecialization();
     }
+
+    RedeclarableTemplateDecl *LatestDecl = 
+        cast_or_null<RedeclarableTemplateDecl>(Reader.GetDecl(Record[Idx++]));
+    assert(LatestDecl->getKind() == D->getKind() && "Latest kind mismatch");
+    D->getCommonPtr()->Latest = LatestDecl;
   }
 }
 
diff --git a/lib/Frontend/PCHWriterDecl.cpp b/lib/Frontend/PCHWriterDecl.cpp
index 3ac49584a5..75045eb32a 100644
--- a/lib/Frontend/PCHWriterDecl.cpp
+++ b/lib/Frontend/PCHWriterDecl.cpp
@@ -852,6 +852,8 @@ void PCHDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
     Writer.AddDeclRef(D->getInstantiatedFromMemberTemplate(), Record);
     if (D->getInstantiatedFromMemberTemplate())
       Record.push_back(D->isMemberSpecialization());
+
+    Writer.AddDeclRef(D->getCommonPtr()->Latest, Record);
   }
 }