FW: ompd_get_thread_id in OMPD implementation

[Ahmed Sayed Mousse <ahmedsayedmousse@gmail.com>]

Sorry for the late reply.
I did check gomp_thread_self but I'm still not sure about what I should do,
maybe because I lack experience/knowledge.
Here is where my thinking is going right now and I hope you tell me if I'm
wrong.

in gomp_thread_to_pthread_t there are 4 possible outputs
1 - if LIBGOMP_USE_PTHREADS is enabled
 {
    first  pthread_self() if the thread calling is the same thread as the
function input.
    or  gomp_thread->handle in case GOMP_NEEDS_THREAD_HANDLE is enabled.
    or  pthread_self () + ((uintptr_t) input_thread - (uintptr_t)
calling_thread)
}
2 -if LIBGOMP_USE_PTHREADS not enabled
        - empty struct casted to a pthread_t
currently think i should check for the GOMP_NEED_THREAD_HANDLE, if it's
enabled i extract the pthread_t  from the gomp_thread handle given in the
function and return that.
If it's not enabled then I return an empty struct or an rc_unspported
return code.
Note:
    The openmp specification doesn't really tell me how things should be
done so I get confused a lot and I think I have a misunderstanding of the
function.
     I would appreciate it a lot if I get any directions to where I can
increase my knowledge around this part.

*From: *Ahmed Sayed Mousse <ahmedsayedmousse@gmail.com>
*Sent: *Wednesday, March 23, 2022 7:23 PM
*To: *gcc-help@gcc.gnu.org
*Cc: *jakub@redhat.com
*Subject: *ompd_get_thread_id in OMPD implementation



Hi everyone,

I was doing a research to help me implement the function
“ompd_get_thread_id” from the OpenMP API specification under section
20.5.5.5.



In this function I need to return a native thread identifier and from
research I found that it’s a “pthread_t” handle which exists inside a
struct named “gomp_thread” of the “libgomp.h” file. The problem is that
this handle isn’t always defined and to show what I mean look at the code
below.



struct gomp_thread

{

…..



#if defined(LIBGOMP_USE_PTHREADS) \

    && (!defined(HAVE_TLS) \

                || !defined(__GLIBC__) \

                || !defined(USING_INITIAL_EXEC_TLS))

#define GOMP_NEEDS_THREAD_HANDLE 1

  pthread_t handle;

#endif

};



I use a macro to calculate the offset of this handle and use the this
offset to get it from memory and I thought I would just check for
GOMP_NEEDS_THREAD_HANDLE before trying to calculate this offset but It
still causes errors and also if that handle isn’t defined then what should
I return as a native identifier?



Thanks for help.