On 03/06/2014 12:11 PM, Ilya Verbin wrote:
Do I understand correctly, that you propose to do so:
extern void *_omp_host_func_table[];
extern void *_omp_host_var_table[];
extern void *_omp_host_funcs_end[];
extern void *_omp_host_vars_end[];
void *__OPENMP_TARGET_HOST__[]
__attribute__ ((visibility ("protected"))) =
{
&_omp_host_func_table, &_omp_host_funcs_end,
&_omp_host_var_table, &_omp_host_vars_end
};
So far, yes (maybe just call it __OPENMP_HOST_TABLE__).
extern void *__OPENMP_TARGET_MIC__[];
extern void *__OPENMP_TARGET_PTX__[];
extern void GOMP_offload_register_host (const void *);
extern void GOMP_offload_register_target (const void *);
__attribute__ ((constructor))
static void
init (void)
{
GOMP_offload_register_host (__OPENMP_TARGET_HOST__);
GOMP_offload_register_target (__OPENMP_TARGET_MIC__);
GOMP_offload_register_target (__OPENMP_TARGET_PTX__);
}
Where __OPENMP_TARGET_MIC__ and __OPENMP_TARGET_PTX__ descriptors
should be generated in the corresponding mkoffload tools.
No. I don't think we need a global constructor for registering
__OPENMP_TARGET_HOST__ - this would unnecessarily bloat crtbegin/crtend.
We also shouldn't need to have the target tables known outside of the
image constructed by the mkoffload tools. The way I imagine it, every
mkoffload tool creates its own constructor that looks like something
like this:
__attribute__ ((constructor)) static void
init (void)
{
GOMP_offload_register_target (__OPENMP_TARGET_HOST__,
PTX_ID, ptx_target_table);
}
That creates a mapping between host and target table for PTX_ID. If
there are multiple shared libraries with offload support, you can still
obtain the ordering you want from these GOMP_offload_register_target
calls. Everything is nicely private to the mkoffload-generated image.
It's implemented in almost this fashion (slightly different naming and
args, and no real support in libgomp) in the patch kit I sent.
Bernd
