features.h

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// This file's extension implies that it's C, but it's really -*- C++ -*-.
/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef CXXUTILS_FEATURES_H
#define CXXUTILS_FEATURES_H
 
#if __has_include( <features.h> )
# include <features.h>
#endif
#if __has_include( <version> )
# include <version>
#endif
 
// If we're using glibc, this should have been defined by features.h.
// Otherwise, define a dummy.
#ifndef __GLIBC_PREREQ
# define __GLIBC_PREREQ(MAJOR, MINOR) 0
#endif

#if (defined(__GNUC__) || defined(__clang__)) &&      \
     !(defined(__ICC) || defined(__COVERITY__) ||     \
       defined(__CUDACC__) || defined(__CLING__))
# define HAVE_GCC_CLANG_EXTENSIONS 1
#else
# define HAVE_GCC_CLANG_EXTENSIONS 0
#endif

#if HAVE_GCC_CLANG_EXTENSIONS &&                                     \
  (defined(__i386__) || defined(__x86_64__)) && defined(__ELF__) &&  \
  !defined(__HIP__) && !defined(CL_SYCL_LANGUAGE_VERSION) &&         \
  !defined(SYCL_LANGUAGE_VERSION)
#define HAVE_FUNCTION_MULTIVERSIONING 1
#else
# define HAVE_FUNCTION_MULTIVERSIONING 0
#endif

#if HAVE_FUNCTION_MULTIVERSIONING && !(defined(__clang__) && __clang_major__ < 14)
# define HAVE_TARGET_CLONES 1
#else
# define HAVE_TARGET_CLONES 0
#endif

#if HAVE_GCC_CLANG_EXTENSIONS && !defined(__clang__)
# define HAVE_GCC_INTRINSICS 1
#else
# define HAVE_GCC_INTRINSICS 0
#endif

// __builtin_ctz
// __builtin_ctzl
// __builtin_ctzll
// __builtin_clz
// __builtin_clzl
// __builtin_clzll
// __builtin_popcount
// __builtin_popcountl
// __builtin_popcountll
#if HAVE_GCC_CLANG_EXTENSIONS
# define HAVE_BITCOUNT_INTRINSICS 1
#else
# define HAVE_BITCOUNT_INTRINSICS 0
#endif
 
// Do we have the vector_size attribute for writing explicitly
// vectorized code?
#if HAVE_GCC_CLANG_EXTENSIONS
# define HAVE_VECTOR_SIZE_ATTRIBUTE 1
#else
# define HAVE_VECTOR_SIZE_ATTRIBUTE 0
#endif
 
// Do we additionally support the clang
// __builtin_convertvector
// GCC>=9 does
#if HAVE_VECTOR_SIZE_ATTRIBUTE && (defined(__clang__) || (__GNUC__ >= 9))
# define HAVE_CONVERT_VECTOR 1
#else
# define HAVE_CONVERT_VECTOR 0
#endif
 
// Do we have mallinfo2?  Present in glibc 2.33,
// in which mallinfo is deprecated.
# if __GLIBC_PREREQ(2, 33)
# define HAVE_MALLINFO2 1
#else
# define HAVE_MALLINFO2 0
#endif
 
 
// Do we have malloc hooks?  They were removed in glibc 2.34.
#if !__GLIBC_PREREQ(2, 34)
# define HAVE_MALLOC_HOOKS 1
#else
# define HAVE_MALLOC_HOOKS 0
#endif
 
// Do we have feenableexcept/fedisableexcept
#if defined(__GLIBC__)
# define HAVE_FEENABLEEXCEPT 1
#else
# define HAVE_FEENABLEEXCEPT 0
#endif
 
// Do we have C++20 ranges?
#if __cpp_lib_ranges
# define HAVE_STD_RANGES 1
#else
# define HAVE_STD_RANGES 0
#endif
 
 
#endif // not CXXUTILS_FEATURES_H