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Diffstat (limited to 'm4/ax_gcc_func_attribute.m4')
| -rw-r--r-- | m4/ax_gcc_func_attribute.m4 | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/m4/ax_gcc_func_attribute.m4 b/m4/ax_gcc_func_attribute.m4 new file mode 100644 index 0000000..f2af85b --- /dev/null +++ b/m4/ax_gcc_func_attribute.m4 @@ -0,0 +1,244 @@ +# SPDX-License-Identifier: FSFAP +# +# =========================================================================== +# https://www.gnu.org/software/autoconf-archive/ax_gcc_func_attribute.html +# =========================================================================== +# +# SYNOPSIS +# +# AX_GCC_FUNC_ATTRIBUTE(ATTRIBUTE) +# +# DESCRIPTION +# +# This macro checks if the compiler supports one of GCC's function +# attributes; many other compilers also provide function attributes with +# the same syntax. Compiler warnings are used to detect supported +# attributes as unsupported ones are ignored by default so quieting +# warnings when using this macro will yield false positives. +# +# The ATTRIBUTE parameter holds the name of the attribute to be checked. +# +# If ATTRIBUTE is supported define HAVE_FUNC_ATTRIBUTE_<ATTRIBUTE>. +# +# The macro caches its result in the ax_cv_have_func_attribute_<attribute> +# variable. +# +# The macro currently supports the following function attributes: +# +# alias +# aligned +# alloc_size +# always_inline +# artificial +# cold +# const +# constructor +# constructor_priority for constructor attribute with priority +# deprecated +# destructor +# dllexport +# dllimport +# error +# externally_visible +# fallthrough +# flatten +# format +# format_arg +# gnu_format +# gnu_inline +# hot +# ifunc +# leaf +# malloc +# noclone +# noinline +# nonnull +# noreturn +# nothrow +# optimize +# pure +# sentinel +# sentinel_position +# unused +# used +# visibility +# warning +# warn_unused_result +# weak +# weakref +# +# Unsupported function attributes will be tested with a prototype +# returning an int and not accepting any arguments and the result of the +# check might be wrong or meaningless so use with care. +# +# LICENSE +# +# Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com> +# +# Copying and distribution of this file, with or without modification, are +# permitted in any medium without royalty provided the copyright notice +# and this notice are preserved. This file is offered as-is, without any +# warranty. + +#serial 10 + +AC_DEFUN([AX_GCC_FUNC_ATTRIBUTE], [ + AS_VAR_PUSHDEF([ac_var], [ax_cv_have_func_attribute_$1]) + + AC_CACHE_CHECK([for __attribute__(($1))], [ac_var], [ + AC_LINK_IFELSE([AC_LANG_PROGRAM([ + m4_case([$1], + [alias], [ + int foo( void ) { return 0; } + int bar( void ) __attribute__(($1("foo"))); + ], + [aligned], [ + int foo( void ) __attribute__(($1(32))); + ], + [alloc_size], [ + void *foo(int a) __attribute__(($1(1))); + ], + [always_inline], [ + inline __attribute__(($1)) int foo( void ) { return 0; } + ], + [artificial], [ + inline __attribute__(($1)) int foo( void ) { return 0; } + ], + [cold], [ + int foo( void ) __attribute__(($1)); + ], + [const], [ + int foo( void ) __attribute__(($1)); + ], + [constructor_priority], [ + int foo( void ) __attribute__((__constructor__(65535/2))); + ], + [constructor], [ + int foo( void ) __attribute__(($1)); + ], + [deprecated], [ + int foo( void ) __attribute__(($1(""))); + ], + [destructor], [ + int foo( void ) __attribute__(($1)); + ], + [dllexport], [ + __attribute__(($1)) int foo( void ) { return 0; } + ], + [dllimport], [ + int foo( void ) __attribute__(($1)); + ], + [error], [ + int foo( void ) __attribute__(($1(""))); + ], + [externally_visible], [ + int foo( void ) __attribute__(($1)); + ], + [fallthrough], [ + int foo( void ) {switch (0) { case 1: __attribute__(($1)); case 2: break ; }}; + ], + [flatten], [ + int foo( void ) __attribute__(($1)); + ], + [format], [ + int foo(const char *p, ...) __attribute__(($1(printf, 1, 2))); + ], + [gnu_format], [ + int foo(const char *p, ...) __attribute__((format(gnu_printf, 1, 2))); + ], + [format_arg], [ + char *foo(const char *p) __attribute__(($1(1))); + ], + [gnu_inline], [ + inline __attribute__(($1)) int foo( void ) { return 0; } + ], + [hot], [ + int foo( void ) __attribute__(($1)); + ], + [ifunc], [ + int my_foo( void ) { return 0; } + static int (*resolve_foo(void))(void) { return my_foo; } + int foo( void ) __attribute__(($1("resolve_foo"))); + ], + [leaf], [ + __attribute__(($1)) int foo( void ) { return 0; } + ], + [malloc], [ + void *foo( void ) __attribute__(($1)); + ], + [noclone], [ + int foo( void ) __attribute__(($1)); + ], + [noinline], [ + __attribute__(($1)) int foo( void ) { return 0; } + ], + [nonnull], [ + int foo(char *p) __attribute__(($1(1))); + ], + [noreturn], [ + void foo( void ) __attribute__(($1)); + ], + [nothrow], [ + int foo( void ) __attribute__(($1)); + ], + [optimize], [ + __attribute__(($1(3))) int foo( void ) { return 0; } + ], + [pure], [ + int foo( void ) __attribute__(($1)); + ], + [sentinel], [ + int foo(void *p, ...) __attribute__(($1)); + ], + [sentinel_position], [ + int foo(void *p, ...) __attribute__(($1(1))); + ], + [returns_nonnull], [ + void *foo( void ) __attribute__(($1)); + ], + [unused], [ + int foo( void ) __attribute__(($1)); + ], + [used], [ + int foo( void ) __attribute__(($1)); + ], + [visibility], [ + int foo_def( void ) __attribute__(($1("default"))); + int foo_hid( void ) __attribute__(($1("hidden"))); + int foo_int( void ) __attribute__(($1("internal"))); + int foo_pro( void ) __attribute__(($1("protected"))); + ], + [warning], [ + int foo( void ) __attribute__(($1(""))); + ], + [warn_unused_result], [ + int foo( void ) __attribute__(($1)); + ], + [weak], [ + int foo( void ) __attribute__(($1)); + ], + [weakref], [ + static int foo( void ) { return 0; } + static int bar( void ) __attribute__(($1("foo"))); + ], + [ + m4_warn([syntax], [Unsupported attribute $1, the test may fail]) + int foo( void ) __attribute__(($1)); + ] + )], []) + ], + dnl GCC doesn't exit with an error if an unknown attribute is + dnl provided but only outputs a warning, so accept the attribute + dnl only if no warning were issued. + [AS_IF([test -s conftest.err], + [AS_VAR_SET([ac_var], [no])], + [AS_VAR_SET([ac_var], [yes])])], + [AS_VAR_SET([ac_var], [no])]) + ]) + + AS_IF([test yes = AS_VAR_GET([ac_var])], + [AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_FUNC_ATTRIBUTE_$1), 1, + [Define to 1 if the system has the `$1' function attribute])], []) + + AS_VAR_POPDEF([ac_var]) +]) |