base/allocator/partition_allocator/partition_alloc_notreached.h

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_ALLOCATOR_PARTITION_ALLOCATOR_PARTITION_ALLOC_NOTREACHED_H_
#define BASE_ALLOCATOR_PARTITION_ALLOCATOR_PARTITION_ALLOC_NOTREACHED_H_

#include "base/allocator/partition_allocator/logging_buildflags.h"
#include "base/allocator/partition_allocator/partition_alloc_base/compiler_specific.h"
#include "base/allocator/partition_allocator/partition_alloc_base/debug/debugging_buildflags.h"
#include "base/allocator/partition_allocator/partition_alloc_buildflags.h"
#include "base/allocator/partition_allocator/partition_alloc_check.h"

// When PartitionAlloc is used as the default allocator, we cannot use the
// regular (D)CHECK() macros, as they allocate internally. (c.f. //
// base/allocator/partition_allocator/partition_alloc_check.h)
// So PA_NOTREACHED() uses PA_DCHECK() instead of DCHECK().

#if BUILDFLAG(PA_ENABLE_LOG_ERROR_NOT_REACHED)
#define PA_NOTREACHED()                                                    \
  true ? ::partition_alloc::internal::logging::RawError(                   \
             __FILE__ "(" PA_STRINGIFY(__LINE__) ") PA_NOTREACHED() hit.") \
       : PA_EAT_CHECK_STREAM_PARAMS()

#elif BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC) && defined(OFFICIAL_BUILD) && \
    defined(NDEBUG) && BUILDFLAG(PA_DCHECK_IS_ON)

// PA_DCHECK(condition) is PA_CHECK(condition) if BUILDFLAG(PA_DCHECK_IS_ON).
// When BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC), OFFICIAL_BUILD,
// NDEBUG are defined, PA_CHECK(false) is IMMEDIATE_CRASH(). Since
// IMMEDIATE_CRASH() hints __builtin_unreachable() to the compiler, the
// following code causes compile failure:
//   switch(...) {
//     ...
//     case X:
//       PA_DCHECK(false);
//       [[fallthrough]]; // The compiler knows "not reached".
//     case Y:
//     ...
// So define PA_NOTREACHED() by using async-signal-safe RawCheck().
#define PA_NOTREACHED()                                               \
  PA_UNLIKELY(true)                                                   \
  ? ::partition_alloc::internal::logging::RawCheck(                   \
        __FILE__ "(" PA_STRINGIFY(__LINE__) ") PA_NOTREACHED() hit.") \
  : PA_EAT_CHECK_STREAM_PARAMS()

#else

// PA_CHECK() uses RawCheck() for error reporting. So "PA_DCHECK(false);
// [[fallthrough]];" doesn't cause compile failure.
#define PA_NOTREACHED() PA_DCHECK(false)

#endif

#endif  // BASE_ALLOCATOR_PARTITION_ALLOCATOR_PARTITION_ALLOC_NOTREACHED_H_