[clang][AST] Pass ProfileArguments by value in findSpecialization{Imp…

…l,Locally} The arguments passed are lightweight (an ArrayRef and a pointer), and findSpecializationImpl passes them to multiple functions, making it a potential hazard to pass them by rvalue reference (even though no one was in fact moving them).
llvm · HighCommander4 · May 12, 2025 · May 12, 2025 · May 12, 2025 · 069edae907f41f127ac1f4010a7e01acbc494b40
commit 069edae907f41f127ac1f4010a7e01acbc494b40
diff --git a/clang/include/clang/AST/DeclTemplate.h b/clang/include/clang/AST/DeclTemplate.h
@@ -781,16 +781,15 @@ class RedeclarableTemplateDecl : public TemplateDecl,
  bool loadLazySpecializationsImpl(llvm::ArrayRef<TemplateArgument> Args,
                                   TemplateParameterList *TPL = nullptr) const;

-  template <class EntryType, typename ...ProfileArguments>
-  typename SpecEntryTraits<EntryType>::DeclType*
+  template <class EntryType, typename... ProfileArguments>
+  typename SpecEntryTraits<EntryType>::DeclType *
  findSpecializationImpl(llvm::FoldingSetVector<EntryType> &Specs,
-                         void *&InsertPos, ProfileArguments &&...ProfileArgs);
+                         void *&InsertPos, ProfileArguments... ProfileArgs);

  template <class EntryType, typename... ProfileArguments>
  typename SpecEntryTraits<EntryType>::DeclType *
  findSpecializationLocally(llvm::FoldingSetVector<EntryType> &Specs,
-                            void *&InsertPos,
-                            ProfileArguments &&...ProfileArgs);
+                            void *&InsertPos, ProfileArguments... ProfileArgs);

  template <class Derived, class EntryType>
  void addSpecializationImpl(llvm::FoldingSetVector<EntryType> &Specs,

diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
@@ -382,12 +382,11 @@ template <class EntryType, typename... ProfileArguments>
 typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
 RedeclarableTemplateDecl::findSpecializationLocally(
    llvm::FoldingSetVector<EntryType> &Specs, void *&InsertPos,
-    ProfileArguments &&...ProfileArgs) {
+    ProfileArguments... ProfileArgs) {
  using SETraits = RedeclarableTemplateDecl::SpecEntryTraits<EntryType>;

  llvm::FoldingSetNodeID ID;
-  EntryType::Profile(ID, std::forward<ProfileArguments>(ProfileArgs)...,
-                     getASTContext());
+  EntryType::Profile(ID, ProfileArgs..., getASTContext());
  EntryType *Entry = Specs.FindNodeOrInsertPos(ID, InsertPos);
  return Entry ? SETraits::getDecl(Entry)->getMostRecentDecl() : nullptr;
 }
@@ -396,18 +395,15 @@ template <class EntryType, typename... ProfileArguments>
 typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
 RedeclarableTemplateDecl::findSpecializationImpl(
    llvm::FoldingSetVector<EntryType> &Specs, void *&InsertPos,
-    ProfileArguments &&...ProfileArgs) {
+    ProfileArguments... ProfileArgs) {

-  if (auto *Found = findSpecializationLocally(
-          Specs, InsertPos, std::forward<ProfileArguments>(ProfileArgs)...))
+  if (auto *Found = findSpecializationLocally(Specs, InsertPos, ProfileArgs...))
    return Found;

-  if (!loadLazySpecializationsImpl(
-          std::forward<ProfileArguments>(ProfileArgs)...))
+  if (!loadLazySpecializationsImpl(ProfileArgs...))
    return nullptr;

-  return findSpecializationLocally(
-      Specs, InsertPos, std::forward<ProfileArguments>(ProfileArgs)...);
+  return findSpecializationLocally(Specs, InsertPos, ProfileArgs...);
 }

 template<class Derived, class EntryType>