vtk-m2/vtkm/internal/Unreachable.h
Kenneth Moreland 3dd66e852a Do not use __assume for icc in gcc compatability mode
When using the GNU header files on a system, the icc compiler emulates
the behavior of the gcc compiler on the system. (See https://
software.intel.com/en-us/node/522750) This appears to mean that icc
features that are not available in gcc could get turned off. In
particular, we found that the __assume feature stopped working.

To get around this problem, do not use __assume when compiling with icc
and __GNUC__ is defined. Instead, use the available gcc features.
2018-04-04 15:00:03 -06:00

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4.4 KiB
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//============================================================================
// Copyright (c) Kitware, Inc.
// All rights reserved.
// See LICENSE.txt for details.
// This software is distributed WITHOUT ANY WARRANTY; without even
// the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
// PURPOSE. See the above copyright notice for more information.
//
// Copyright 2017 National Technology & Engineering Solutions of Sandia, LLC (NTESS).
// Copyright 2017 UT-Battelle, LLC.
// Copyright 2017 Los Alamos National Security.
//
// Under the terms of Contract DE-NA0003525 with NTESS,
// the U.S. Government retains certain rights in this software.
//
// Under the terms of Contract DE-AC52-06NA25396 with Los Alamos National
// Laboratory (LANL), the U.S. Government retains certain rights in
// this software.
//============================================================================
#ifndef vtk_m_Unreachable_h
#define vtk_m_Unreachable_h
/// VTKM_UNREACHABLE is similar to VTK_ASSUME, with the significant difference
/// that it is not conditional. Control should never reach a path containing
/// a VTKM_UNREACHABLE statement under any circumstances.
///
/// If assertions are enabled (e.g. neither NDEBUG nor VTKM_NO_ASSERT is
/// defined), the following steps are taken:
/// 1. Print an error message containing the macro argument and location of the
/// VTKM_UNREACHABLE call.
/// 2. Abort the kernel (if CUDA) or process.
///
/// This allows bad code paths to be identified during development and
/// debugging.
///
/// If assertions are disabled and the compiler has some sort of 'unreachable'
/// intrinsic used to provide optimization hints, the intrinsic is used to
/// notify the compiler that this is a dead code path.
///
#define VTKM_UNREACHABLE(msg) \
VTKM_SWALLOW_SEMICOLON_PRE_BLOCK \
{ \
VTKM_UNREACHABLE_IMPL(); \
VTKM_UNREACHABLE_PRINT(msg); \
VTKM_UNREACHABLE_ABORT(); \
} \
VTKM_SWALLOW_SEMICOLON_POST_BLOCK
// VTKM_UNREACHABLE_IMPL is compiler-specific:
#if defined(__CUDA_ARCH__)
#define VTKM_UNREACHABLE_IMPL() (void)0 /* no-op, no known intrinsic */
#if defined(NDEBUG) || defined(VTKM_NO_ASSERT)
#define VTKM_UNREACHABLE_PRINT(msg) (void)0 /* no-op */
#define VTKM_UNREACHABLE_ABORT() (void)0 /* no-op */
#else // NDEBUG || VTKM_NO_ASSERT
#define VTKM_UNREACHABLE_PRINT(msg) \
printf("Unreachable location reached: %s\nLocation: %s:%d\n", msg, __FILE__, __LINE__)
#define VTKM_UNREACHABLE_ABORT() \
asm("trap;") /* Triggers kernel exit with CUDA error 73: Illegal inst */
#endif // NDEBUG || VTKM_NO_ASSERT
#else // !CUDA
#if defined(NDEBUG) || defined(VTKM_NO_ASSERT)
#define VTKM_UNREACHABLE_PRINT(msg) (void)0 /* no-op */
#define VTKM_UNREACHABLE_ABORT() (void)0 /* no-op */
#if defined(VTKM_MSVC)
#define VTKM_UNREACHABLE_IMPL() __assume(false)
#elif defined(VTKM_ICC) && !defined(__GNUC__)
#define VTKM_UNREACHABLE_IMPL() __assume(false)
#elif (defined(VTKM_GCC) || defined(VTKM_ICC)) && \
(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))
// Added in 4.5.0:
#define VTKM_UNREACHABLE_IMPL() __builtin_unreachable()
#elif defined(VTKM_CLANG)
#define VTKM_UNREACHABLE_IMPL() __builtin_unreachable()
#else
#define VTKM_UNREACHABLE_IMPL() (void)0 /* no-op */
#endif
#else // NDEBUG || VTKM_NO_ASSERT
#define VTKM_UNREACHABLE_IMPL() (void)0
#define VTKM_UNREACHABLE_PRINT(msg) \
std::cerr << "Unreachable location reached: " << msg << "\n" \
<< "Location: " << __FILE__ << ":" << __LINE__ << "\n"
#define VTKM_UNREACHABLE_ABORT() abort()
#endif // NDEBUG && !VTKM_NO_ASSERT
#endif // !CUDA
#endif //vtk_m_Unreachable_h