If I want to disable certain attributes, such as "swiftcall", isthere any way to do it now?

[Aaron Ballman via cfe-commits]

On Wed, May 2, 2018 at 4:59 AM, 朴素 <772847235 at qq.com> wrote:
> Thanks.
>
> If I remove some specific attributes, now I can think of the following
> method.First of all, let me talk about my method.
>
> 1.Define target platforms that do not support attributes.such as def
> TargetPower : TargetArch<["ppc", "ppc64", "ppc64le"]>;
>
> 2.Define TargetNotSupportedAttr class.such as class
> TargetNotSupportedAttr<TargetArch target> ;

Why not make use of TargetSpecificAttr to mark the attributes that are
specific to a target rather than marking the attributes not supported
by a target?

> 3.Using this approach, we need to modify the
> cfe-4.0.1.src/utils/TableGen/ClangAttrEmitter.cpp file.Modifying the code in
> the GenerateHasAttrSpellingStringSwitch function looks like this:
>
> if(Attr->isSubClassOf("TargetNotSupportedAttr")) {   // add
>
> #define GenerateTargetNotSupportedAttrChecks
> GenerateTargetSpecificAttrChecks // add
>
>         const Record *R = Attr->getValueAsDef("Target");   // add
>
>         std::vector<std::string> Arches =
> R->getValueAsListOfStrings("Arches"); // add
>
>         GenerateTargetNotSupportedAttrChecks(R, Arches, Test, nullptr);
> // add
>
>         TestStr = !Test.empty() ? Test + " ? "  + " 0 :" +
> llvm::itostr(Version) : "0"; // add
>
>     } else if (Attr->isSubClassOf("TargetSpecificAttr"))
>
> 4.And for classes that inherit from TargetNotSupportedAttr<> class, we don’t
> need to generate the attribute class, so add the following code in
> EmitClangAttrClass
>
> if (R->getName() != "TargetSpecificAttr" &&
>
>               R->getName() != "TargetNotSupportedAttr” &&  //add
>
>               SuperName.empty())
>
>         SuperName = R->getName();
>
>
> If I use this method, is it correct?

It seems like it would work, yes.

~Aaron

>
>
>
>
> ------------------ 原始邮件 ------------------
> 发件人: "Aaron Ballman"<aaron at aaronballman.com>;
> 发送时间: 2018年4月29日(星期天) 凌晨3:07
> 收件人: "朴素"<772847235 at qq.com>;
> 抄送: "cfe-commits"<cfe-commits at lists.llvm.org>;
> 主题: Re: If I want to disable certain attributes, such as "swiftcall",
> isthere any way to do it now?
>
> On Fri, Apr 27, 2018 at 11:23 PM, 朴素 via cfe-commits
> <cfe-commits at lists.llvm.org> wrote:
>>    As the title says,thanks.
>
> You could build a custom clang with specific attributes removed, but
> there are no compiler flags that allow you to disable arbitrary
> attributes like swiftcall.
>
> ~Aaron