On Fri, Apr 7, 2017 at 2:53 PM, Richard Smith <rich...@metafoo.co.uk> wrote: > On 7 Apr 2017 11:49 am, "David Majnemer via cfe-commits" > <cfe-commits@lists.llvm.org> wrote: > > > > On Fri, Apr 7, 2017 at 8:30 AM, Aaron Ballman via cfe-commits > <cfe-commits@lists.llvm.org> wrote: >> >> On Fri, Apr 7, 2017 at 11:13 AM, Saleem Abdulrasool via cfe-commits >> <cfe-commits@lists.llvm.org> wrote: >> > Author: compnerd >> > Date: Fri Apr 7 10:13:47 2017 >> > New Revision: 299774 >> > >> > URL: http://llvm.org/viewvc/llvm-project?rev=299774&view=rev >> > Log: >> > Sema: prevent __declspec(naked) use on x64 >> > >> > MSDN (https://msdn.microsoft.com/en-us/library/h5w10wxs.aspx) indicates >> > that `__declspec(naked)` is only permitted on x86 and ARM targets. >> > Testing with cl does confirm this behaviour. Provide a warning for use >> > of `__declspec(naked)` on x64. >> >> Your patch is not providing a warning, it's providing an error, which >> seems inappropriate (to me). Why is this attribute not silently >> ignored there instead? > > > FWIW, MSVC diagnoses this with an error: https://godbolt.org/g/T5sQr5 > > > Is there a reason we can't support this? Was our existing support broken in > some way? We generally allow our features to be combined in arbitrary ways > unless there's a reason not to.
For the __declspec spelling of the attribute, we shouldn't really do *more* than what Microsoft allows, should we (even if we can)? As for error vs warning, I was mostly pointing out that (1) the commit comment doesn't match the behavior of the patch, which is always a concern, and (2) most of our attributes warn rather than err, unless there's a solid reason to err. If LLVM gets a naked attribute for a function and the architecture doesn't support the concept, what happens? I thought it ignored it (which suggests a warning rather than an error, to a certain extent), but I could be wrong. ~Aaron > >> (Btw, I did not see a review thread for this, did I miss one?) More >> comments below. >> >> > >> > Added: >> > cfe/trunk/test/Sema/declspec-naked.c >> > Modified: >> > cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td >> > cfe/trunk/lib/Sema/SemaDeclAttr.cpp >> > cfe/trunk/test/Sema/ms-inline-asm.c >> > >> > Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td >> > URL: >> > http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=299774&r1=299773&r2=299774&view=diff >> > >> > ============================================================================== >> > --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original) >> > +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Apr 7 >> > 10:13:47 2017 >> > @@ -3231,7 +3231,8 @@ def err_attribute_regparm_invalid_number >> > "'regparm' parameter must be between 0 and %0 inclusive">; >> > def err_attribute_not_supported_in_lang : Error< >> > "%0 attribute is not supported in %select{C|C++|Objective-C}1">; >> > - >> > +def err_attribute_not_supported_on_arch >> > + : Error<"%0 attribute is not supported on '%1'">; >> > >> > // Clang-Specific Attributes >> > def warn_attribute_iboutlet : Warning< >> > >> > Modified: cfe/trunk/lib/Sema/SemaDeclAttr.cpp >> > URL: >> > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclAttr.cpp?rev=299774&r1=299773&r2=299774&view=diff >> > >> > ============================================================================== >> > --- cfe/trunk/lib/Sema/SemaDeclAttr.cpp (original) >> > +++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp Fri Apr 7 10:13:47 2017 >> > @@ -1923,6 +1923,17 @@ static void handleNakedAttr(Sema &S, Dec >> > Attr.getName())) >> > return; >> > >> > + if (Attr.isDeclspecAttribute()) { >> > + const auto &Triple = S.getASTContext().getTargetInfo().getTriple(); >> >> No need to have the Triple variable (which is a rather poor name given >> that it's also the type name). >> > + const auto &Arch = Triple.getArch(); >> >> Do not use auto for either of these. >> >> ~Aaron >> >> > + if (Arch != llvm::Triple::x86 && >> > + (Arch != llvm::Triple::arm && Arch != llvm::Triple::thumb)) { >> > + S.Diag(Attr.getLoc(), diag::err_attribute_not_supported_on_arch) >> > + << Attr.getName() << Triple.getArchName(); >> > + return; >> > + } >> > + } >> > + >> > D->addAttr(::new (S.Context) NakedAttr(Attr.getRange(), S.Context, >> > >> > Attr.getAttributeSpellingListIndex())); >> > } >> > >> > Added: cfe/trunk/test/Sema/declspec-naked.c >> > URL: >> > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/declspec-naked.c?rev=299774&view=auto >> > >> > ============================================================================== >> > --- cfe/trunk/test/Sema/declspec-naked.c (added) >> > +++ cfe/trunk/test/Sema/declspec-naked.c Fri Apr 7 10:13:47 2017 >> > @@ -0,0 +1,11 @@ >> > +// RUN: %clang_cc1 -triple i686-unknown-windows-msvc -fsyntax-only >> > -fdeclspec -verify %s >> > +// RUN: %clang_cc1 -triple thumbv7-unknown-windows-msvc -fsyntax-only >> > -fdeclspec -verify %s >> > +// RUN: %clang_cc1 -triple x86_64-unknown-windows-msvc -fsyntax-only >> > -fdeclspec -verify %s >> > +#if defined(_M_IX86) || defined(_M_ARM) >> > +// CHECK: expected-no-diagnostics >> > +#endif >> > + >> > +void __declspec(naked) f(void) {} >> > +#if !defined(_M_IX86) && !defined(_M_ARM) >> > +// expected-error@-2{{'naked' attribute is not supported on 'x86_64'}} >> > +#endif >> > >> > Modified: cfe/trunk/test/Sema/ms-inline-asm.c >> > URL: >> > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/ms-inline-asm.c?rev=299774&r1=299773&r2=299774&view=diff >> > >> > ============================================================================== >> > --- cfe/trunk/test/Sema/ms-inline-asm.c (original) >> > +++ cfe/trunk/test/Sema/ms-inline-asm.c Fri Apr 7 10:13:47 2017 >> > @@ -1,5 +1,5 @@ >> > // REQUIRES: x86-registered-target >> > -// RUN: %clang_cc1 %s -triple x86_64-apple-darwin10 -fms-extensions >> > -fasm-blocks -Wno-microsoft -Wunused-label -verify -fsyntax-only >> > +// RUN: %clang_cc1 %s -triple i386-apple-darwin10 -fms-extensions >> > -fasm-blocks -Wno-microsoft -Wunused-label -verify -fsyntax-only >> > >> > void t1(void) { >> > __asm __asm // expected-error {{__asm used with no assembly >> > instructions}} >> > >> > >> > _______________________________________________ >> > cfe-commits mailing list >> > cfe-commits@lists.llvm.org >> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >> _______________________________________________ >> cfe-commits mailing list >> cfe-commits@lists.llvm.org >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits > > > > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits > > _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
