llvm-project/compiler-rt/test/tsan/mop_with_offset.cc

// RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
#include <pthread.h>
#include <stddef.h>
#include <stdio.h>
#include <unistd.h>

void *Thread1(void *x) {
  int *p = (int*)x;
  p[0] = 1;
  return NULL;
}

void *Thread2(void *x) {
  sleep(1);
  char *p = (char*)x;
  p[2] = 1;
  return NULL;
}

int main() {
  int *data = new int(42);
  fprintf(stderr, "ptr1=%p\n", data);
  fprintf(stderr, "ptr2=%p\n", (char*)data + 2);
  pthread_t t[2];
  pthread_create(&t[0], NULL, Thread1, data);
  pthread_create(&t[1], NULL, Thread2, data);
  pthread_join(t[0], NULL);
  pthread_join(t[1], NULL);
  delete data;
}

// CHECK: ptr1=[[PTR1:0x[0-9,a-f]+]]
// CHECK: ptr2=[[PTR2:0x[0-9,a-f]+]]
// CHECK: WARNING: ThreadSanitizer: data race
// CHECK:   Write of size 1 at [[PTR2]] by thread T2:
// CHECK:   Previous write of size 4 at [[PTR1]] by thread T1: