[cfe-dev] CABI project

[Dave Abrahams]

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on Tue Oct 16 2012, John McCall <rjmccall-AT-apple.com> wrote:

> On Oct 16, 2012, at 11:45 AM, Dave Abrahams wrote:
>> I'm working on a project to separate from Clang all the logic necessary
>> to generate C/C++/ObjC-ABI-compatible code so that other front-ends,
>> both C family (e.g. Dragonegg, and in BoostPro's case, EDG) and other
>> languages/code generators, can interoperate with C family code.
>
> So, specifically, this would be some sort of API where you give it a C
> function type and it tells you how to pass those arguments in LLVM IR?

Oh, way more than that.  It has to deal with exception-handling, object
layout, vtable layout, yada yada... and probably a few
ObjectiveC-specific things I don't know about (not being versed in
ObjC).

> Seems commendable, but there's a lot of hidden complexity here.

Don't I know it!  As I mentioned, I've been digging around in the code
extensively and it's clearly a nontrivial undertaking.

> Is there anything more to it than that?  Are you also going to try to
> abstract, say, the sizes and alignments of fundamental types?

yes

> Struct layout?  Anything else?

yes and yes.  Lots else.

>> Eventually I want to put this work in a separate project that sits
>> between Clang and LLVM, but for now, at Chandler's suggestion, I plan to
>> make it a sub-library of Clang (I'll set up the CMakeLists.txt so the
>> CABI library can't see the rest of clang).
>
> Sounds reasonable.
>
>> Suggestions, feedback, interaction welcomed.  Not my highest priority,
>> but if anyone has a better name than CABI it would relieve one nagging
>> source of discomfort ;-)
>
> If it's just about the C ABI, that seems like a fine name for it.

No, it's C/C++/ObjC ABI.

-- 
Dave Abrahams
BoostPro Computing                  Software Development        Training
http://www.boostpro.com             Clang/LLVM/EDG Compilers  C++  Boost