Factor code into CXXRecordDecl::getTemplateInstantiationPattern() helper

This moves some code from SemaType.cpp's hasVisibleDefinition() into
DeclCXX.cpp so that it can be used elsewhere. I found one other instance
of code trying to do the same thing, there are probably more. Search for
getInstantiatedFrom() to try to find more.

No functionality change.

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D5783

llvm-svn: 219714

2 files changed, 4 insertions, 39 deletions

diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 639e6511217..cbeebb2ac98 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -1175,21 +1175,8 @@ static Module *getDefiningModule(Decl *Entity) {
     if (FunctionDecl *Pattern = FD->getTemplateInstantiationPattern())
       Entity = Pattern;
   } else if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Entity)) {
-    // If it's a class template specialization, find the template or partial
-    // specialization from which it was instantiated.
-    if (ClassTemplateSpecializationDecl *SpecRD =
-            dyn_cast<ClassTemplateSpecializationDecl>(RD)) {
-      llvm::PointerUnion<ClassTemplateDecl*,
-                         ClassTemplatePartialSpecializationDecl*> From =
-          SpecRD->getInstantiatedFrom();
-      if (ClassTemplateDecl *FromTemplate = From.dyn_cast<ClassTemplateDecl*>())
-        Entity = FromTemplate->getTemplatedDecl();
-      else if (From)
-        Entity = From.get<ClassTemplatePartialSpecializationDecl*>();
-      // Otherwise, it's an explicit specialization.
-    } else if (MemberSpecializationInfo *MSInfo =
-                   RD->getMemberSpecializationInfo())
-      Entity = getInstantiatedFrom(RD, MSInfo);
+    if (CXXRecordDecl *Pattern = RD->getTemplateInstantiationPattern())
+      Entity = Pattern;
   } else if (EnumDecl *ED = dyn_cast<EnumDecl>(Entity)) {
     if (MemberSpecializationInfo *MSInfo = ED->getMemberSpecializationInfo())
       Entity = getInstantiatedFrom(ED, MSInfo);
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 31d7f73e097..3ce9489fdd2 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5085,31 +5085,9 @@ static bool hasVisibleDefinition(Sema &S, NamedDecl *D, NamedDecl **Suggested) {
 
   // If this definition was instantiated from a template, map back to the
   // pattern from which it was instantiated.
-  //
-  // FIXME: There must be a better place for this to live.
   if (auto *RD = dyn_cast<CXXRecordDecl>(D)) {
-    if (auto *TD = dyn_cast<ClassTemplateSpecializationDecl>(RD)) {
-      auto From = TD->getInstantiatedFrom();
-      if (auto *CTD = From.dyn_cast<ClassTemplateDecl*>()) {
-        while (auto *NewCTD = CTD->getInstantiatedFromMemberTemplate()) {
-          if (NewCTD->isMemberSpecialization())
-            break;
-          CTD = NewCTD;
-        }
-        RD = CTD->getTemplatedDecl();
-      } else if (auto *CTPSD = From.dyn_cast<
-                     ClassTemplatePartialSpecializationDecl *>()) {
-        while (auto *NewCTPSD = CTPSD->getInstantiatedFromMember()) {
-          if (NewCTPSD->isMemberSpecialization())
-            break;
-          CTPSD = NewCTPSD;
-        }
-        RD = CTPSD;
-      }
-    } else if (isTemplateInstantiation(RD->getTemplateSpecializationKind())) {
-      while (auto *NewRD = RD->getInstantiatedFromMemberClass())
-        RD = NewRD;
-    }
+    if (auto *Pattern = RD->getTemplateInstantiationPattern())
+      RD = Pattern;
     D = RD->getDefinition();
   } else if (auto *ED = dyn_cast<EnumDecl>(D)) {
     while (auto *NewED = ED->getInstantiatedFromMemberEnum())