| blob | c788ca9bd435fbfe4e1642281aabd7f9492786ff |
1 # ===========================================================================
2 # http://www.gnu.org/software/autoconf-archive/ax_gcc_func_attribute.html
3 # ===========================================================================
4 #
5 # SYNOPSIS
6 #
7 # AX_GCC_FUNC_ATTRIBUTE(ATTRIBUTE)
8 #
9 # DESCRIPTION
10 #
11 # This macro checks if the compiler supports one of GCC's function
12 # attributes; many other compilers also provide function attributes with
13 # the same syntax. Compiler warnings are used to detect supported
14 # attributes as unsupported ones are ignored by default so quieting
15 # warnings when using this macro will yield false positives.
16 #
17 # The ATTRIBUTE parameter holds the name of the attribute to be checked.
18 #
19 # If ATTRIBUTE is supported define HAVE_FUNC_ATTRIBUTE_<ATTRIBUTE>.
20 #
21 # The macro caches its result in the ax_cv_have_func_attribute_<attribute>
22 # variable.
23 #
24 # The macro currently supports the following function attributes:
25 #
26 # alias
27 # aligned
28 # alloc_size
29 # always_inline
30 # artificial
31 # cold
32 # const
33 # constructor
34 # constructor_priority for constructor attribute with priority
35 # deprecated
36 # destructor
37 # dllexport
38 # dllimport
39 # error
40 # externally_visible
41 # flatten
42 # format
43 # format_arg
44 # gnu_inline
45 # hot
46 # ifunc
47 # leaf
48 # malloc
49 # noclone
50 # noinline
51 # nonnull
52 # noreturn
53 # nothrow
54 # optimize
55 # pure
56 # unused
57 # used
58 # visibility
59 # warning
60 # warn_unused_result
61 # weak
62 # weakref
63 #
64 # Unsuppored function attributes will be tested with a prototype returning
65 # an int and not accepting any arguments and the result of the check might
66 # be wrong or meaningless so use with care.
67 #
68 # LICENSE
69 #
70 # Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com>
71 #
72 # Copying and distribution of this file, with or without modification, are
73 # permitted in any medium without royalty provided the copyright notice
74 # and this notice are preserved. This file is offered as-is, without any
75 # warranty.
77 #serial 3
79 AC_DEFUN([AX_GCC_FUNC_ATTRIBUTE], [
80 AS_VAR_PUSHDEF([ac_var], [ax_cv_have_func_attribute_$1])
82 AC_CACHE_CHECK([for __attribute__(($1))], [ac_var], [
83 AC_LINK_IFELSE([AC_LANG_PROGRAM([
84 m4_case([$1],
85 [alias], [
86 int foo( void ) { return 0; }
87 int bar( void ) __attribute__(($1("foo")));
88 ],
89 [aligned], [
90 int foo( void ) __attribute__(($1(32)));
91 ],
92 [alloc_size], [
93 void *foo(int a) __attribute__(($1(1)));
94 ],
95 [always_inline], [
96 inline __attribute__(($1)) int foo( void ) { return 0; }
97 ],
98 [artificial], [
99 inline __attribute__(($1)) int foo( void ) { return 0; }
100 ],
101 [cold], [
102 int foo( void ) __attribute__(($1));
103 ],
104 [const], [
105 int foo( void ) __attribute__(($1));
106 ],
107 [constructor_priority], [
108 int foo( void ) __attribute__((__constructor__(65535/2)));
109 ],
110 [constructor], [
111 int foo( void ) __attribute__(($1));
112 ],
113 [deprecated], [
114 int foo( void ) __attribute__(($1("")));
115 ],
116 [destructor], [
117 int foo( void ) __attribute__(($1));
118 ],
119 [dllexport], [
120 __attribute__(($1)) int foo( void ) { return 0; }
121 ],
122 [dllimport], [
123 int foo( void ) __attribute__(($1));
124 ],
125 [error], [
126 int foo( void ) __attribute__(($1("")));
127 ],
128 [externally_visible], [
129 int foo( void ) __attribute__(($1));
130 ],
131 [flatten], [
132 int foo( void ) __attribute__(($1));
133 ],
134 [format], [
135 int foo(const char *p, ...) __attribute__(($1(printf, 1, 2)));
136 ],
137 [format_arg], [
138 char *foo(const char *p) __attribute__(($1(1)));
139 ],
140 [gnu_inline], [
141 inline __attribute__(($1)) int foo( void ) { return 0; }
142 ],
143 [hot], [
144 int foo( void ) __attribute__(($1));
145 ],
146 [ifunc], [
147 int my_foo( void ) { return 0; }
148 static int (*resolve_foo(void))(void) { return my_foo; }
149 int foo( void ) __attribute__(($1("resolve_foo")));
150 ],
151 [leaf], [
152 __attribute__(($1)) int foo( void ) { return 0; }
153 ],
154 [malloc], [
155 void *foo( void ) __attribute__(($1));
156 ],
157 [noclone], [
158 int foo( void ) __attribute__(($1));
159 ],
160 [noinline], [
161 __attribute__(($1)) int foo( void ) { return 0; }
162 ],
163 [nonnull], [
164 int foo(char *p) __attribute__(($1(1)));
165 ],
166 [noreturn], [
167 void foo( void ) __attribute__(($1));
168 ],
169 [nothrow], [
170 int foo( void ) __attribute__(($1));
171 ],
172 [optimize], [
173 __attribute__(($1(3))) int foo( void ) { return 0; }
174 ],
175 [pure], [
176 int foo( void ) __attribute__(($1));
177 ],
178 [unused], [
179 int foo( void ) __attribute__(($1));
180 ],
181 [used], [
182 int foo( void ) __attribute__(($1));
183 ],
184 [visibility], [
185 int foo_def( void ) __attribute__(($1("default")));
186 int foo_hid( void ) __attribute__(($1("hidden")));
187 int foo_int( void ) __attribute__(($1("internal")));
188 int foo_pro( void ) __attribute__(($1("protected")));
189 ],
190 [warning], [
191 int foo( void ) __attribute__(($1("")));
192 ],
193 [warn_unused_result], [
194 int foo( void ) __attribute__(($1));
195 ],
196 [weak], [
197 int foo( void ) __attribute__(($1));
198 ],
199 [weakref], [
200 static int foo( void ) { return 0; }
201 static int bar( void ) __attribute__(($1("foo")));
202 ],
203 [
204 m4_warn([syntax], [Unsupported attribute $1, the test may fail])
205 int foo( void ) __attribute__(($1));
206 ]
207 )], [])
208 ],
209 dnl GCC doesn't exit with an error if an unknown attribute is
210 dnl provided but only outputs a warning, so accept the attribute
211 dnl only if no warning were issued.
212 [AS_IF([test -s conftest.err],
213 [AS_VAR_SET([ac_var], [no])],
214 [AS_VAR_SET([ac_var], [yes])])],
215 [AS_VAR_SET([ac_var], [no])])
216 ])
218 AS_IF([test yes = AS_VAR_GET([ac_var])],
219 [AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_FUNC_ATTRIBUTE_$1), 1,
220 [Define to 1 if the system has the `$1' function attribute])], [])
222 AS_VAR_POPDEF([ac_var])
223 ])