1 files changed, 67 insertions, 0 deletions
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index b6bb611..e5fba1b 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -1708,3 +1708,70 @@ TemplateParameterList *clang::getReplacedTemplateParameterList(const Decl *D) {
     llvm_unreachable("Unhandled templated declaration kind");
   }
 }
+
+const Decl &clang::adjustDeclToTemplate(const Decl &D) {
+  if (const auto *FD = dyn_cast<FunctionDecl>(&D)) {
+    // Is this function declaration part of a function template?
+    if (const FunctionTemplateDecl *FTD = FD->getDescribedFunctionTemplate())
+      return *FTD;
+
+    // Nothing to do if function is not an implicit instantiation.
+    if (FD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
+      return D;
+
+    // Function is an implicit instantiation of a function template?
+    if (const FunctionTemplateDecl *FTD = FD->getPrimaryTemplate())
+      return *FTD;
+
+    // Function is instantiated from a member definition of a class template?
+    if (const FunctionDecl *MemberDecl =
+            FD->getInstantiatedFromMemberFunction())
+      return *MemberDecl;
+
+    return D;
+  }
+  if (const auto *VD = dyn_cast<VarDecl>(&D)) {
+    // Static data member is instantiated from a member definition of a class
+    // template?
+    if (VD->isStaticDataMember())
+      if (const VarDecl *MemberDecl = VD->getInstantiatedFromStaticDataMember())
+        return *MemberDecl;
+
+    return D;
+  }
+  if (const auto *CRD = dyn_cast<CXXRecordDecl>(&D)) {
+    // Is this class declaration part of a class template?
+    if (const ClassTemplateDecl *CTD = CRD->getDescribedClassTemplate())
+      return *CTD;
+
+    // Class is an implicit instantiation of a class template or partial
+    // specialization?
+    if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(CRD)) {
+      if (CTSD->getSpecializationKind() != TSK_ImplicitInstantiation)
+        return D;
+      llvm::PointerUnion<ClassTemplateDecl *,
+                         ClassTemplatePartialSpecializationDecl *>
+          PU = CTSD->getSpecializedTemplateOrPartial();
+      return isa<ClassTemplateDecl *>(PU)
+                 ? *static_cast<const Decl *>(cast<ClassTemplateDecl *>(PU))
+                 : *static_cast<const Decl *>(
+                       cast<ClassTemplatePartialSpecializationDecl *>(PU));
+    }
+
+    // Class is instantiated from a member definition of a class template?
+    if (const MemberSpecializationInfo *Info =
+            CRD->getMemberSpecializationInfo())
+      return *Info->getInstantiatedFrom();
+
+    return D;
+  }
+  if (const auto *ED = dyn_cast<EnumDecl>(&D)) {
+    // Enum is instantiated from a member definition of a class template?
+    if (const EnumDecl *MemberDecl = ED->getInstantiatedFromMemberEnum())
+      return *MemberDecl;
+
+    return D;
+  }
+  // FIXME: Adjust alias templates?
+  return D;
+}