r299774 - Sema: prevent __declspec(naked) use on x64

Aaron Ballman via cfe-commits cfe-commits at lists.llvm.org
Fri Apr 7 08:30:09 PDT 2017


On Fri, Apr 7, 2017 at 11:13 AM, Saleem Abdulrasool via cfe-commits
<cfe-commits at 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?

(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 at -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}}
>
>
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