compiler-rt/test/tsan/aligned_vs_unaligned_race.cpp

   1 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t 2>&1 | FileCheck %s
   2 // Race between an aligned access and an unaligned access, which
   3 // touches the same memory region.
   4 #include "test.h"
   5 #include <stdint.h>
   6
   7 uint64_t Global[2];
   8
   9 void *Thread1(void *x) {
  10   Global[1]++;
  11   barrier_wait(&barrier);
  12   return NULL;
  13 }
  14
  15 void *Thread2(void *x) {
  16   barrier_wait(&barrier);
  17   char *p1 = reinterpret_cast<char *>(&Global[0]);
  18   struct __attribute__((packed, aligned(1))) u_uint64_t { uint64_t val; };
  19   u_uint64_t *p4 = reinterpret_cast<u_uint64_t *>(p1 + 1);
  20   (*p4).val++;
  21   return NULL;
  22 }
  23
  24 int main() {
  25   barrier_init(&barrier, 2);
  26   pthread_t t[2];
  27   pthread_create(&t[0], NULL, Thread1, NULL);
  28   pthread_create(&t[1], NULL, Thread2, NULL);
  29   pthread_join(t[0], NULL);
  30   pthread_join(t[1], NULL);
  31   fprintf(stderr, "Pass\n");
  32   // CHECK: ThreadSanitizer: data race
  33   // CHECK: Pass
  34   return 0;
  35 }