[Bug go/88500] [SH]: SETCONTEXT_CLOBBERS_TLS needs to be handled in libgo

[ian at airs dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88500

--- Comment #1 from Ian Lance Taylor <ian at airs dot com> ---
SETCONTEXT_CLOBBERS_TLS is set by libgo/configure.ac if this program fails to
exit successfully.  So the first step in fixing this bug is finding out why
this program fails on SH.


#include <pthread.h>
#include <stdlib.h>
#include <ucontext.h>
#include <unistd.h>

__thread int tls;

static char stack[[10 * 1024 * 1024]];
static ucontext_t c;

/* Called via makecontext/setcontext.  */

static void
cfn (void)
{
  exit (tls);
}

/* Called via pthread_create.  */

static void *
tfn (void *dummy)
{
  /* The thread should still see this value after calling
     setcontext.  */
  tls = 0;

  setcontext (&c);

  /* The call to setcontext should not return.  */
  abort ();
}

int
main ()
{
  pthread_t tid;

  /* The thread should not see this value.  */
  tls = 1;

  if (getcontext (&c) < 0)
    abort ();

  c.uc_stack.ss_sp = stack;
#ifdef MAKECONTEXT_STACK_TOP
  c.uc_stack.ss_sp += sizeof stack;
#endif
  c.uc_stack.ss_flags = 0;
  c.uc_stack.ss_size = sizeof stack;
  c.uc_link = NULL;
  makecontext (&c, cfn, 0);

  if (pthread_create (&tid, NULL, tfn, NULL) != 0)
    abort ();

  if (pthread_join (tid, NULL) != 0)
    abort ();

  /* The thread should have called exit.  */
  abort ();
}