[cfe-dev] OpenCL parsing / type support

[Anton Lokhmotov]

I am also looking into OpenCL support in Clang, and am learning quite a few
of hacks Chris and Arnaud are referring to.  It would be good, however, to
implement OpenCL features properly, so that setting LangOpts.OpenCL=1 would
just work.  I suggest we make a conscious community-wide effort here so that
various implementations do not reinvent the wheel. (So Arnaud it would be
great if you could contribute to Clang head your patch for address space and
kernel attributes!)

Right now I'm staring into TokenKinds.def.  One issue there is the use of
KEYALL for

a) non-C99 (and hence automatically non-OpenCL) keywords (e.g. __func__)
b) GNU extensions (e.g. _Decimal32, __builtin_choose_expr) 
c) MS extensions (e.g. __forceinline and __declspec).  

This means that a Clang-based OpenCL front-end may not accept these as valid
identifiers, although the standard does not list them as keywords!  It's
easy to make existing keywords valid for OpenCL but it's not so easy to
exclude them (e.g. valid in almost all C variants but invalid in OpenCL).

I appreciate many people are busy with preparing for release 2.7 but this is
something we should address sooner rather than later.

Anton L.