diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp index 04b818260ffa..0dc47d5db93d 100644 --- a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp +++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp @@ -58,6 +58,18 @@ bool hasLoopStmtAncestor(const DeclRefExpr &DeclRef, const Decl &Decl, return Matches.empty(); } +bool isExplicitTemplateSpecialization(const FunctionDecl &Function) { + if (const auto *SpecializationInfo = Function.getTemplateSpecializationInfo()) + if (SpecializationInfo->getTemplateSpecializationKind() == + TSK_ExplicitSpecialization) + return true; + if (const auto *Method = llvm::dyn_cast(&Function)) + if (Method->getTemplatedKind() == FunctionDecl::TK_MemberSpecialization && + Method->getMemberSpecializationInfo()->isExplicitSpecialization()) + return true; + return false; +} + } // namespace UnnecessaryValueParamCheck::UnnecessaryValueParamCheck( @@ -133,9 +145,11 @@ void UnnecessaryValueParamCheck::check(const MatchFinder::MatchResult &Result) { // 2. the function is virtual as it might break overrides // 3. the function is referenced outside of a call expression within the // compilation unit as the signature change could introduce build errors. + // 4. the function is an explicit template specialization. const auto *Method = llvm::dyn_cast(Function); if (Param->getLocStart().isMacroID() || (Method && Method->isVirtual()) || - isReferencedOutsideOfCallExpr(*Function, *Result.Context)) + isReferencedOutsideOfCallExpr(*Function, *Result.Context) || + isExplicitTemplateSpecialization(*Function)) return; for (const auto *FunctionDecl = Function; FunctionDecl != nullptr; FunctionDecl = FunctionDecl->getPreviousDecl()) { diff --git a/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp b/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp index 5491cbb80c0d..dcf82df2e385 100644 --- a/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp +++ b/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp @@ -348,3 +348,14 @@ void fun() { ExpensiveToCopyType E; NegativeUsingConstructor S(E); } + +template +void templateFunction(T) { +} + +template<> +void templateFunction(ExpensiveToCopyType E) { + // CHECK-MESSAGES: [[@LINE-1]]:64: warning: the parameter 'E' is copied + // CHECK-FIXES: void templateFunction(ExpensiveToCopyType E) { + E.constReference(); +}