1 files changed, 41 insertions, 5 deletions

diff --git a/lib/AST/DeclTemplate.cpp b/lib/AST/DeclTemplate.cpp
index 848427e7f9d9e..76f29dac1647d 100644
--- a/lib/AST/DeclTemplate.cpp
+++ b/lib/AST/DeclTemplate.cpp
@@ -149,6 +149,8 @@ void *allocateDefaultArgStorageChain(const ASTContext &C) {
 // RedeclarableTemplateDecl Implementation
 //===----------------------------------------------------------------------===//
 
+void RedeclarableTemplateDecl::anchor() {}
+
 RedeclarableTemplateDecl::CommonBase *RedeclarableTemplateDecl::getCommonPtr() const {
   if (Common)
     return Common;
@@ -300,6 +302,40 @@ ArrayRef<TemplateArgument> FunctionTemplateDecl::getInjectedTemplateArgs() {
   return llvm::makeArrayRef(CommonPtr->InjectedArgs, Params->size());
 }
 
+void FunctionTemplateDecl::mergePrevDecl(FunctionTemplateDecl *Prev) {
+  using Base = RedeclarableTemplateDecl;
+
+  // If we haven't created a common pointer yet, then it can just be created
+  // with the usual method.
+  if (!Base::Common)
+    return;
+
+  Common *ThisCommon = static_cast<Common *>(Base::Common);
+  Common *PrevCommon = nullptr;
+  SmallVector<FunctionTemplateDecl *, 8> PreviousDecls;
+  for (; Prev; Prev = Prev->getPreviousDecl()) {
+    if (Prev->Base::Common) {
+      PrevCommon = static_cast<Common *>(Prev->Base::Common);
+      break;
+    }
+    PreviousDecls.push_back(Prev);
+  }
+
+  // If the previous redecl chain hasn't created a common pointer yet, then just
+  // use this common pointer.
+  if (!PrevCommon) {
+    for (auto *D : PreviousDecls)
+      D->Base::Common = ThisCommon;
+    return;
+  }
+
+  // Ensure we don't leak any important state.
+  assert(ThisCommon->Specializations.size() == 0 &&
+         "Can't merge incompatible declarations!");
+
+  Base::Common = PrevCommon;
+}
+
 //===----------------------------------------------------------------------===//
 // ClassTemplateDecl Implementation
 //===----------------------------------------------------------------------===//
@@ -473,7 +509,7 @@ SourceLocation TemplateTypeParmDecl::getDefaultArgumentLoc() const {
 
 SourceRange TemplateTypeParmDecl::getSourceRange() const {
   if (hasDefaultArgument() && !defaultArgumentWasInherited())
-    return SourceRange(getLocStart(),
+    return SourceRange(getBeginLoc(),
                        getDefaultArgumentInfo()->getTypeLoc().getEndLoc());
   else
     return TypeDecl::getSourceRange();
@@ -712,7 +748,7 @@ ClassTemplateSpecializationDecl::Create(ASTContext &Context, TagKind TK,
       new (Context, DC) ClassTemplateSpecializationDecl(
           Context, ClassTemplateSpecialization, TK, DC, StartLoc, IdLoc,
           SpecializedTemplate, Args, PrevDecl);
-  Result->MayHaveOutOfDateDef = false;
+  Result->setMayHaveOutOfDateDef(false);
 
   Context.getTypeDeclType(Result, PrevDecl);
   return Result;
@@ -723,7 +759,7 @@ ClassTemplateSpecializationDecl::CreateDeserialized(ASTContext &C,
                                                     unsigned ID) {
   auto *Result =
     new (C, ID) ClassTemplateSpecializationDecl(C, ClassTemplateSpecialization);
-  Result->MayHaveOutOfDateDef = false;
+  Result->setMayHaveOutOfDateDef(false);
   return Result;
 }
 
@@ -830,7 +866,7 @@ Create(ASTContext &Context, TagKind TK,DeclContext *DC,
                                              Params, SpecializedTemplate, Args,
                                              ASTArgInfos, PrevDecl);
   Result->setSpecializationKind(TSK_ExplicitSpecialization);
-  Result->MayHaveOutOfDateDef = false;
+  Result->setMayHaveOutOfDateDef(false);
 
   Context.getInjectedClassNameType(Result, CanonInjectedType);
   return Result;
@@ -840,7 +876,7 @@ ClassTemplatePartialSpecializationDecl *
 ClassTemplatePartialSpecializationDecl::CreateDeserialized(ASTContext &C,
                                                            unsigned ID) {
   auto *Result = new (C, ID) ClassTemplatePartialSpecializationDecl(C);
-  Result->MayHaveOutOfDateDef = false;
+  Result->setMayHaveOutOfDateDef(false);
   return Result;
 }