[PATCH] Initial support for Attribute subjects

[Aaron Ballman]

Ping?

On Mon, Jun 24, 2013 at 1:34 PM, Aaron Ballman <aaron at aaronballman.com> wrote:
> Based on feedback from Richard, here is another pass at modifying
> tablegen for Subjects support.  The delta here is that templates have
> been removed and replaced by a method pair (one for Decl and one for
> Stmt).  The usage is still the same as before: you can call
> appertainsTo and pass in something you want to know whether the
> attribute appertains to it or not, and it will return a Boolean.
>
> ~Aaron
>
> On Thu, Jun 20, 2013 at 5:34 PM, Aaron Ballman <aaron at aaronballman.com> wrote:
>> This patch adds support for the Subjects part of the Attr tablegen
>> file.  Specifically, it modifies tablegen to pay attention to
>> Subjects, and emit a templated member function for attribute
>> subclasses called appertainTo.  The purpose is to be able to determine
>> whether a given attribute appertains to a particular subject.
>>
>> template <typename Subject>
>> bool appertainTo(const Subject *S) const;
>>
>> If the attribute has no subjects, then the default behavior of
>> appertainTo is to return true.  This makes it backwards compatible
>> with the fact that we've always ignored subjects previously (and many
>> attributes do not have a specific subject specified).
>>
>> If the attribute does have subjects, then the default appertainTo will
>> return false, but specializations will be generated that return true
>> for each subject case.  If the subject happens to be a SubsetSubject,
>> the code from CheckCode is emitted (hence the reason for having the
>> subject passed into the function) and the proper base is taken from
>> the subject.
>>
>> ~Aaron