compiler-rt/test/tsan/test.h

#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <dlfcn.h>
#include <stddef.h>

// TSan-invisible barrier.
// Tests use it to establish necessary execution order in a way that does not
// interfere with tsan (does not establish synchronization between threads).
// 8 lsb is thread count, the remaining are count of entered threads.
typedef unsigned long long invisible_barrier_t;

void barrier_init(invisible_barrier_t *barrier, unsigned count) {
  if (count >= (1 << 8))
      exit(fprintf(stderr, "barrier_init: count is too large (%d)\n", count));
  *barrier = count;
}

void barrier_wait(invisible_barrier_t *barrier) {
  unsigned old = __atomic_fetch_add(barrier, 1 << 8, __ATOMIC_RELAXED);
  unsigned old_epoch = (old >> 8) / (old & 0xff);
  for (;;) {
    unsigned cur = __atomic_load_n(barrier, __ATOMIC_RELAXED);
    unsigned cur_epoch = (cur >> 8) / (cur & 0xff);
    if (cur_epoch != old_epoch)
      return;
    usleep(1000);
  }
}

// Default instance of the barrier, but a test can declare more manually.
invisible_barrier_t barrier;

void print_address(void *address) {
// On FreeBSD, the %p conversion specifier works as 0x%x and thus does not match
// to the format used in the diagnotic message.
#ifdef __x86_64__
  fprintf(stderr, "0x%012lx", (unsigned long) address);
#elif defined(__mips64)
  fprintf(stderr, "0x%010lx", (unsigned long) address);
#elif defined(__aarch64__)
  // AArch64 currently has 3 different VMA (39, 42, and 48 bits) and it requires
  // different pointer size to match the diagnostic message.
  const char *format = 0;
  unsigned long vma = (unsigned long)__builtin_frame_address(0);
  vma = 64 - __builtin_clzll(vma);
  if (vma == 39)
    format = "0x%010lx";
  else if (vma == 42)
    format = "0x%011lx";
  else {
    fprintf(stderr, "unsupported vma: %ul\n", vma);
    exit(1);
  }

  fprintf(stderr, format, (unsigned long) address);
#endif
}