[Mesa-dev] build failure: _mesa_BindAttribLocation vs _mesa_lookup_shader_program_err , GLuint vs GLhandleARB

[Jeremy Huddleston Sequoia]

I'm getting this build failure:

main/shader_query.cpp:49:7: error: no matching function for call to '_mesa_lookup_shader_program_err'
      _mesa_lookup_shader_program_err(ctx, program, "glBindAttribLocation");
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../src/mesa/main/shaderobj.h:81:1: note: candidate function not viable: cannot convert argument of incomplete type 'GLhandleARB'
      (aka 'void *') to 'GLuint' (aka 'unsigned int')
_mesa_lookup_shader_program_err(struct gl_context *ctx, GLuint name,
^

_mesa_lookup_shader_program_err is defined as:

extern struct gl_shader_program *
_mesa_lookup_shader_program_err(struct gl_context *ctx, GLuint name,
                                const char *caller);


but it is being passed a GLhandleARB rather than an GLuint by _mesa_BindAttribLocation:

void GLAPIENTRY
_mesa_BindAttribLocation(GLhandleARB program, GLhandleARB index,
                            const GLcharARB *name)
{
   GET_CURRENT_CONTEXT(ctx);

   struct gl_shader_program *const shProg =
      _mesa_lookup_shader_program_err(ctx, program, "glBindAttribLocation");
...

This seems like an old bug that is just now coming to light.  The main reason nobody else seems to have hit this in a while is that on most platforms, GLhandleARB and GLuint are both 'unsigned integer', so the compiler happily goes back and forth between the two, but on darwin, GLhandleARB is a void * and thus cannot be implicitly cast to an unsigned int:

#ifdef __APPLE__
typedef void *GLhandleARB;
#else
typedef unsigned int GLhandleARB;
#endif

How should we address this?  I'd really really really prefer to not have to put a bunch of casts everywhere, and I'm ok breaking binary compatibility on darwin in fixing this.

--Jeremy