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

[朴素 via cfe-commits]

hi, Aaron
   
   Can I ask you some questions?Is there such a demand for me in the community? Does my code need to be submitted to the community?
   Thanks.
------------------ 原始邮件 ------------------
发件人: "Aaron Ballman"<aaron at aaronballman.com>;
发送时间: 2018年5月3日(星期四) 晚上7:40
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 Thu, May 3, 2018 at 1:25 AM, 朴素 <772847235 at qq.com> wrote:
> hi, Aaron
>
>   The reason why i not use of TargetSpecificAttr is as follows.If I plan to
> support a new platform, I don't want to let users use certain attributes
> because of hardware or simply not want to. Yes, we can use
> TargetSpecificAttr, but if we use TargetSpecificAttr that we need to include
> platforms other than unsupported platforms, but we just need to exclude that
> platform, using TargetSpecificAttr may not be a good idea.

Okay, that makes sense to me. Your design seems like a reasonable one.

~Aaron

>
>
>
> ------------------ 原始邮件 ------------------
> 发件人: "Aaron Ballman"<aaron at aaronballman.com>;
> 发送时间: 2018年5月2日(星期三) 晚上10:05
> 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 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
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