os::realloc(void *memblock, size_t size)

• 引数で渡されたmemblockのサイズを変更する
  • 新たにsize分の領域にする

//(jdk7/hotspot/src/share/vm/runtime/os.cpp)
Void* os::realloc(void *memblock, size_t size) {
#ifndef ASSERT
  NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
  NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));

  //glibcのreallocを呼び出す
  //realloc関数 http://linuxjm.sourceforge.jp/html/LDP_man-pages/man3/free.3.html
  return ::realloc(memblock, size);
#else
  if (memblock == NULL) {
    return malloc(size);
  }
  if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
    tty->print_cr("os::realloc caught " PTR_FORMAT, memblock);
    breakpoint();
  }
  verify_block(memblock);
  NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
  if (size == 0) return NULL;
  // always move the block
  void* ptr = malloc(size);
  if (PrintMalloc) tty->print_cr("os::remalloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, memblock, ptr);
  // Copy to new memory if malloc didn't fail
  if ( ptr != NULL ) {
    memcpy(ptr, memblock, MIN2(size, get_size(memblock)));
    if (paranoid) verify_block(ptr);
    if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
      tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
      breakpoint();
    }
    free(memblock);
  }
  return ptr;
#endif
}