Re: [PATCH, libffi, alpha]: Use FFI_ASSERT in ffi_closure_osf_inner

[Ian Lance Taylor]

On Sat, Sep 20, 2014 at 3:04 AM, Anthony Green <gr...@moxielogic.com> wrote:
>
>> Attached patch fixes libgo reflect test failure with libffi closures.
>> The gccgo compiler started to use FFI closures recently; the compiler
>> passes ffi_type_void for structures with zero members.
>
> Why not just pass an FFI_TYPE_STRUCT with zero members?

Because when an empty struct is used as a return type libffi returns
a failure from ffi_prep_cif_core:

  /* Initialize the return type if necessary */
  if ((cif->rtype->size == 0) && (initialize_aggregate(cif->rtype) != FFI_OK))
    return FFI_BAD_TYPEDEF;

This is because initialize_aggregate fails:

  if (UNLIKELY(arg == NULL || arg->elements == NULL))
    return FFI_BAD_TYPEDEF;

I haven't looked farther.

Ian