diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 0b3c9fed6bdb..d648d2f45f42 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -1407,6 +1407,10 @@ def err_noexcept_needs_constant_expression : Error< "argument to noexcept specifier must be a constant expression">; def err_exception_spec_not_parsed : Error< "exception specification is not available until end of class definition">; +def warn_nothrow_attr_disagrees_with_exception_specification + : ExtWarn<"attribute 'nothrow' ignored due to conflicting exception " + "specification">, + InGroup; // C++ access checking def err_class_redeclared_with_different_access : Error< diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp index 1f4be4405b55..2a13c9576c79 100644 --- a/clang/lib/Sema/SemaDeclAttr.cpp +++ b/clang/lib/Sema/SemaDeclAttr.cpp @@ -1985,6 +1985,25 @@ static void handleNoReturnAttr(Sema &S, Decl *D, const AttributeList &Attrs) { Attrs.getRange(), S.Context, Attrs.getAttributeSpellingListIndex())); } +static void handleNoThrowAttr(Sema &S, Decl *D, const AttributeList &Attrs) { + assert(isa(D) && "attribute nothrow only valid on functions"); + + auto *FD = cast(D); + const auto *FPT = FD->getType()->getAs(); + + if (FPT && FPT->hasExceptionSpec() && + FPT->getExceptionSpecType() != EST_BasicNoexcept) { + S.Diag(Attrs.getLoc(), + diag::warn_nothrow_attr_disagrees_with_exception_specification); + S.Diag(FD->getExceptionSpecSourceRange().getBegin(), + diag::note_previous_decl) + << "exception specification"; + } + + D->addAttr(::new (S.Context) NoThrowAttr( + Attrs.getRange(), S.Context, Attrs.getAttributeSpellingListIndex())); +} + static void handleNoCallerSavedRegsAttr(Sema &S, Decl *D, const AttributeList &Attr) { if (S.CheckNoCallerSavedRegsAttr(Attr)) @@ -6211,7 +6230,7 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, handleNoReturnAttr(S, D, Attr); break; case AttributeList::AT_NoThrow: - handleSimpleAttribute(S, D, Attr); + handleNoThrowAttr(S, D, Attr); break; case AttributeList::AT_CUDAShared: handleSharedAttr(S, D, Attr); diff --git a/clang/test/SemaCXX/warn-conflicting-nothrow-attr-exception-spec.cpp b/clang/test/SemaCXX/warn-conflicting-nothrow-attr-exception-spec.cpp new file mode 100644 index 000000000000..c927c4f92651 --- /dev/null +++ b/clang/test/SemaCXX/warn-conflicting-nothrow-attr-exception-spec.cpp @@ -0,0 +1,24 @@ +// RUN: %clang_cc1 %s -fcxx-exceptions -fsyntax-only -Wexceptions -verify -std=c++14 + +struct S { + //expected-warning@+2 {{attribute 'nothrow' ignored due to conflicting exception specification}} + //expected-note@+1 {{exception specification declared here}} + __attribute__((nothrow)) S() noexcept(true); + //expected-warning@+2 {{attribute 'nothrow' ignored due to conflicting exception specification}} + //expected-note@+1 {{exception specification declared here}} + __attribute__((nothrow)) void Func1() noexcept(false); + __attribute__((nothrow)) void Func3() noexcept; +}; + +void throwing() noexcept(false); +void non_throwing(bool b = true) noexcept; + +template +struct T { + __attribute__((nothrow)) void f(Fn) noexcept(Fn()); +}; + +//expected-warning@-3 {{attribute 'nothrow' ignored due to conflicting exception specification}} +//expected-note@-4 {{exception specification declared here}} +template struct T; +template struct T;