third_party/llvm-project/compiler-rt/test/memprof/TestCases/free_hook_realloc.cpp

// Check that free hook doesn't conflict with Realloc.
// RUN: %clangxx_memprof -O2 %s -o %t && %run %t 2>&1 | FileCheck %s

#include <sanitizer/allocator_interface.h>
#include <stdlib.h>
#include <unistd.h>

static void *glob_ptr;

// (Speculative fix if memprof is enabled on Apple platforms)
// Required for dyld macOS 12.0+
#if (__APPLE__)
__attribute__((weak))
#endif
extern "C" void
__sanitizer_free_hook(const volatile void *ptr) {
  if (ptr == glob_ptr) {
    *(int *)ptr = 0;
    write(1, "FreeHook\n", sizeof("FreeHook\n"));
  }
}

int main() {
  int *x = (int *)malloc(100);
  x[0] = 42;
  glob_ptr = x;
  int *y = (int *)realloc(x, 200);
  // Verify that free hook was called and didn't spoil the memory.
  if (y[0] != 42) {
    _exit(1);
  }
  write(1, "Passed\n", sizeof("Passed\n"));
  free(y);
  // CHECK: FreeHook
  // CHECK: Passed
  return 0;
}