[cfe-commits] [patch] Add codegen support for __uuidof

[Nico Weber]

Any more comments?

On Tue, Oct 2, 2012 at 2:24 PM, Nico Weber <thakis at chromium.org> wrote:
> On Tue, Oct 2, 2012 at 2:11 PM, Eli Friedman <eli.friedman at gmail.com> wrote:
>> On Sun, Sep 30, 2012 at 11:56 PM, Nico Weber <thakis at chromium.org> wrote:
>>> Hi,
>>>
>>> the attached patch adds codegen support for __uuidof. It's fairly
>>> similar to how the RTTI descriptor code works. What __uuidof does:
>>> Structs can be tagged with __declspec(uuid("some string with
>>> numbers")), and after that __uuidof(taggedstruct) returns a IID struct
>>> filled with the numbers from the uuid declspec attribute. See
>>> test/Parser/MicrosoftExtensions.cpp and the included test for more
>>> information.
>>>
>>> I moved GetUuidAttrOfType() out of Sema since codegen now needs it
>>> too. I couldn't find a great place for it -- it's a static function on
>>> CXXUuidofExpr. Since that expression isn't very useful without uuid
>>> attrs, it's a reasonable place for it I think.
>>>
>>> I'm not very familiar with visibilities. WeakAnyLinkage is mostly a
>>> guess, so please check that.
>>>
>>> The name of the symbol generated for __uuidof constants seems to be an
>>> implementation detail, so I just made up a mangling ("__uuid_"
>>> followed by the contents of the uuid, see GetAddrOfIIDDescriptor()).
>>
>> If the linkage is weak, the name matters, because the symbol will be
>> merged with symbols from other compilation units.  You might want to
>> consider marking it internal/constant/unnamed_addr instead, if the
>> address doesn't actually matter; that way, the name is irrelevant, and
>> the compiler and/or linker can still merge them.
>
> Thanks! As far as I can tell that's good enough. Done.