From: Vassil Vassilev Date: Tue, 9 May 2017 11:25:41 +0000 (+0000) Subject: Reland "Warn about unused static file scope function template declarations." X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0de0020819ff7334eadd8252628c9d5f97559a8a;p=clang Reland "Warn about unused static file scope function template declarations." This patch reinstates r299930, reverted in r299956, as a separate diagnostic option (-Wunused-template). git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302518 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td index 05e03fab40..e1a4158402 100644 --- a/include/clang/Basic/DiagnosticGroups.td +++ b/include/clang/Basic/DiagnosticGroups.td @@ -486,6 +486,7 @@ def UnneededInternalDecl : DiagGroup<"unneeded-internal-declaration">; def UnneededMemberFunction : DiagGroup<"unneeded-member-function">; def UnusedPrivateField : DiagGroup<"unused-private-field">; def UnusedFunction : DiagGroup<"unused-function", [UnneededInternalDecl]>; +def UnusedTemplate : DiagGroup<"unused-template", [UnneededInternalDecl]>; def UnusedMemberFunction : DiagGroup<"unused-member-function", [UnneededMemberFunction]>; def UnusedLabel : DiagGroup<"unused-label">; @@ -627,6 +628,7 @@ def Conversion : DiagGroup<"conversion", def Unused : DiagGroup<"unused", [UnusedArgument, UnusedFunction, UnusedLabel, // UnusedParameter, (matches GCC's behavior) + // UnusedTemplate, (clean-up libc++ before enabling) // UnusedMemberFunction, (clean-up llvm before enabling) UnusedPrivateField, UnusedLambdaCapture, UnusedLocalTypedef, UnusedValue, UnusedVariable, diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td index a0c0e5f864..1f3815984c 100644 --- a/include/clang/Basic/DiagnosticSemaKinds.td +++ b/include/clang/Basic/DiagnosticSemaKinds.td @@ -303,6 +303,8 @@ def note_empty_parens_zero_initialize : Note< "replace parentheses with an initializer to declare a variable">; def warn_unused_function : Warning<"unused function %0">, InGroup, DefaultIgnore; +def warn_unused_template : Warning<"unused %select{function|variable}0 template %1">, + InGroup, DefaultIgnore; def warn_unused_member_function : Warning<"unused member function %0">, InGroup, DefaultIgnore; def warn_used_but_marked_unused: Warning<"%0 was marked unused but was used">, diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp index 2f493fa5fb..ca1d27e950 100644 --- a/lib/Sema/Sema.cpp +++ b/lib/Sema/Sema.cpp @@ -477,6 +477,13 @@ static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) { return true; if (const FunctionDecl *FD = dyn_cast(D)) { + // If this is a function template and none of its specializations is used, + // we should warn. + if (FunctionTemplateDecl *Template = FD->getDescribedFunctionTemplate()) + for (const auto *Spec : Template->specializations()) + if (ShouldRemoveFromUnused(SemaRef, Spec)) + return true; + // UnusedFileScopedDecls stores the first declaration. // The declaration may have become definition so check again. const FunctionDecl *DeclToCheck; @@ -500,6 +507,13 @@ static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) { VD->isUsableInConstantExpressions(SemaRef->Context)) return true; + if (VarTemplateDecl *Template = VD->getDescribedVarTemplate()) + // If this is a variable template and none of its specializations is used, + // we should warn. + for (const auto *Spec : Template->specializations()) + if (ShouldRemoveFromUnused(SemaRef, Spec)) + return true; + // UnusedFileScopedDecls stores the first declaration. // The declaration may have become definition so check again. const VarDecl *DeclToCheck = VD->getDefinition(); @@ -905,10 +919,14 @@ void Sema::ActOnEndOfTranslationUnit() { << /*function*/0 << DiagD->getDeclName(); } } else { - Diag(DiagD->getLocation(), - isa(DiagD) ? diag::warn_unused_member_function - : diag::warn_unused_function) - << DiagD->getDeclName(); + if (FD->getDescribedFunctionTemplate()) + Diag(DiagD->getLocation(), diag::warn_unused_template) + << /*function*/0 << DiagD->getDeclName(); + else + Diag(DiagD->getLocation(), + isa(DiagD) ? diag::warn_unused_member_function + : diag::warn_unused_function) + << DiagD->getDeclName(); } } else { const VarDecl *DiagD = cast(*I)->getDefinition(); @@ -924,7 +942,11 @@ void Sema::ActOnEndOfTranslationUnit() { Diag(DiagD->getLocation(), diag::warn_unused_const_variable) << DiagD->getDeclName(); } else { - Diag(DiagD->getLocation(), diag::warn_unused_variable) + if (DiagD->getDescribedVarTemplate()) + Diag(DiagD->getLocation(), diag::warn_unused_template) + << /*variable*/1 << DiagD->getDeclName(); + else + Diag(DiagD->getLocation(), diag::warn_unused_variable) << DiagD->getDeclName(); } } diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp index 2612023f59..2d15c75f48 100644 --- a/lib/Sema/SemaDecl.cpp +++ b/lib/Sema/SemaDecl.cpp @@ -8923,6 +8923,7 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC, if (FunctionTemplate) { if (NewFD->isInvalidDecl()) FunctionTemplate->setInvalidDecl(); + MarkUnusedFileScopedDecl(NewFD); return FunctionTemplate; } } @@ -11023,8 +11024,7 @@ static bool hasDependentAlignment(VarDecl *VD) { /// FinalizeDeclaration - called by ParseDeclarationAfterDeclarator to perform /// any semantic actions necessary after any initializer has been attached. -void -Sema::FinalizeDeclaration(Decl *ThisDecl) { +void Sema::FinalizeDeclaration(Decl *ThisDecl) { // Note that we are no longer parsing the initializer for this declaration. ParsingInitForAutoVars.erase(ThisDecl); @@ -11189,9 +11189,8 @@ Sema::FinalizeDeclaration(Decl *ThisDecl) { if (DC->getRedeclContext()->isFileContext() && VD->isExternallyVisible()) AddPushedVisibilityAttribute(VD); - // FIXME: Warn on unused templates. - if (VD->isFileVarDecl() && !VD->getDescribedVarTemplate() && - !isa(VD)) + // FIXME: Warn on unused var template partial specializations. + if (VD->isFileVarDecl() && !isa(VD)) MarkUnusedFileScopedDecl(VD); // Now we have parsed the initializer and can update the table of magic diff --git a/test/SemaCXX/warn-unused-filescoped.cpp b/test/SemaCXX/warn-unused-filescoped.cpp index 18defee7d0..93c6bbd7ed 100644 --- a/test/SemaCXX/warn-unused-filescoped.cpp +++ b/test/SemaCXX/warn-unused-filescoped.cpp @@ -1,5 +1,5 @@ -// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -Wno-unused-local-typedefs -Wno-c++11-extensions -std=c++98 %s -// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -Wno-unused-local-typedefs -std=c++11 %s +// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-template -Wunused-member-function -Wno-unused-local-typedefs -Wno-c++11-extensions -std=c++98 %s +// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-template -Wunused-member-function -Wno-unused-local-typedefs -std=c++14 %s #ifdef HEADER @@ -65,7 +65,7 @@ namespace { template <> void TS::m() { } // expected-warning{{unused}} template - void tf() { } + void tf() { } // expected-warning{{unused}} template <> void tf() { } // expected-warning{{unused}} struct VS { @@ -200,6 +200,18 @@ void bar() { void func() __attribute__((used)); } static void func() {} } +namespace test9 { +template +static void completeRedeclChainForTemplateSpecialization() { } // expected-warning {{unused}} +} + +namespace test10 { +#if __cplusplus >= 201103L +template +constexpr T pi = T(3.14); // expected-warning {{unused}} +#endif +} + namespace pr19713 { #if __cplusplus >= 201103L // FIXME: We should warn on both of these.