gecko-dev/mfbt/Compiler.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* Various compiler checks. */
#ifndef mozilla_Compiler_h
#define mozilla_Compiler_h
#define MOZ_IS_GCC 0
#define MOZ_IS_MSVC 0
#if !defined(__clang__) && defined(__GNUC__)
# undef MOZ_IS_GCC
# define MOZ_IS_GCC 1
/*
* This macro should simplify gcc version checking. For example, to check
* for gcc 4.7.1 or later, check `#if MOZ_GCC_VERSION_AT_LEAST(4, 7, 1)`.
*/
# define MOZ_GCC_VERSION_AT_LEAST(major, minor, patchlevel) \
((__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) \
>= ((major) * 10000 + (minor) * 100 + (patchlevel)))
# if !MOZ_GCC_VERSION_AT_LEAST(4, 7, 0)
# error "mfbt (and Gecko) require at least gcc 4.7 to build."
# endif
#elif defined(_MSC_VER)
# undef MOZ_IS_MSVC
# define MOZ_IS_MSVC 1
#endif
/*
* The situation with standard libraries is a lot worse than with compilers,
* particularly as clang and gcc could end up using one of three or so standard
* libraries, and they may not be up-to-snuff with newer C++11 versions. To
* detect the library, we're going to include cstddef (which is a small header
* which will be transitively included by everybody else at some point) to grab
* the version macros and deduce macros from there.
*/
#ifdef __cplusplus
# include <cstddef>
# ifdef _STLPORT_MAJOR
# define MOZ_USING_STLPORT 1
# define MOZ_STLPORT_VERSION_AT_LEAST(major, minor, patch) \
(_STLPORT_VERSION >= ((major) << 8 | (minor) << 4 | (patch)))
# elif defined(_LIBCPP_VERSION)
/*
* libc++, unfortunately, doesn't appear to have useful versioning macros.
* Hopefully, the recommendations of N3694 with respect to standard libraries
* will get applied instead and we won't need to worry about version numbers
* here.
*/
# define MOZ_USING_LIBCXX 1
# elif defined(__GLIBCXX__)
# define MOZ_USING_LIBSTDCXX 1
/*
* libstdc++ is also annoying and doesn't give us useful versioning macros
* for the library. If we're using gcc, then assume that libstdc++ matches
* the compiler version. If we're using clang, we're going to have to fake
* major/minor combinations by looking for newly-defined config macros.
*/
# if MOZ_IS_GCC
# define MOZ_LIBSTDCXX_VERSION_AT_LEAST(major, minor, patch) \
MOZ_GCC_VERSION_AT_LEAST(major, minor, patch)
# elif defined(_GLIBCXX_THROW_OR_ABORT)
# define MOZ_LIBSTDCXX_VERSION_AT_LEAST(major, minor, patch) \
((major) < 4 || ((major) == 4 && (minor) <= 8))
# elif defined(_GLIBCXX_NOEXCEPT)
# define MOZ_LIBSTDCXX_VERSION_AT_LEAST(major, minor, patch) \
((major) < 4 || ((major) == 4 && (minor) <= 7))
# elif defined(_GLIBCXX_USE_DEPRECATED)
# define MOZ_LIBSTDCXX_VERSION_AT_LEAST(major, minor, patch) \
((major) < 4 || ((major) == 4 && (minor) <= 6))
# elif defined(_GLIBCXX_PSEUDO_VISIBILITY)
# define MOZ_LIBSTDCXX_VERSION_AT_LEAST(major, minor, patch) \
((major) < 4 || ((major) == 4 && (minor) <= 5))
# elif defined(_GLIBCXX_BEGIN_EXTERN_C)
# define MOZ_LIBSTDCXX_VERSION_AT_LEAST(major, minor, patch) \
((major) < 4 || ((major) == 4 && (minor) <= 4))
# elif defined(_GLIBCXX_VISIBILITY_ATTR)
# define MOZ_LIBSTDCXX_VERSION_AT_LEAST(major, minor, patch) \
((major) < 4 || ((major) == 4 && (minor) <= 3))
# elif defined(_GLIBCXX_VISIBILITY)
# define MOZ_LIBSTDCXX_VERSION_AT_LEAST(major, minor, patch) \
((major) < 4 || ((major) == 4 && (minor) <= 2))
# else
# error "Your version of libstdc++ is unknown to us and is likely too old."
# endif
# endif
// Flesh out the defines for everyone else
# ifndef MOZ_USING_STLPORT
# define MOZ_USING_STLPORT 0
# define MOZ_STLPORT_VERSION_AT_LEAST(major, minor, patch) 0
# endif
# ifndef MOZ_USING_LIBCXX
# define MOZ_USING_LIBCXX 0
# endif
# ifndef MOZ_USING_LIBSTDCXX
# define MOZ_USING_LIBSTDCXX 0
# define MOZ_LIBSTDCXX_VERSION_AT_LEAST(major, minor, patch) 0
# endif
#endif /* __cplusplus */
#endif /* mozilla_Compiler_h */