libc/src/__support/macros/null_check.h

//===-- Safe nullptr check --------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIBC_SRC___SUPPORT_MACROS_NULL_CHECK_H
#define LLVM_LIBC_SRC___SUPPORT_MACROS_NULL_CHECK_H

#include "src/__support/macros/config.h"
#include "src/__support/macros/optimization.h"
#include "src/__support/macros/sanitizer.h"

#if defined(LIBC_ADD_NULL_CHECKS) && !defined(LIBC_HAS_SANITIZER)
// Use volatile to prevent undefined behavior of dereferencing nullptr.
// Intentionally crashing with SIGSEGV.
#define LIBC_CRASH_ON_NULLPTR(PTR)                                             \
  do {                                                                         \
    if (LIBC_UNLIKELY(PTR == nullptr)) {                                       \
      volatile auto *crashing = PTR;                                           \
      [[maybe_unused]] volatile auto crash = *crashing;                        \
      __builtin_trap();                                                        \
    }                                                                          \
  } while (0)
#else
#define LIBC_CRASH_ON_NULLPTR(ptr)                                             \
  do {                                                                         \
  } while (0)
#endif

#endif // LLVM_LIBC_SRC___SUPPORT_MACROS_NULL_CHECK_H