libitm: Don't execute memtransfer/memset if size isn't larger than zero.
[gcc.git] / libitm / acinclude.m4
1 dnl ----------------------------------------------------------------------
2 dnl This whole bit snagged from libgfortran.
3
4 dnl Check whether the target supports __sync_*_compare_and_swap.
5 AC_DEFUN([LIBITM_CHECK_SYNC_BUILTINS], [
6 AC_CACHE_CHECK([whether the target supports __sync_*_compare_and_swap],
7 libitm_cv_have_sync_builtins, [
8 AC_TRY_LINK([], [int foo, bar; bar = __sync_val_compare_and_swap(&foo, 0, 1);],
9 libitm_cv_have_sync_builtins=yes, libitm_cv_have_sync_builtins=no)])
10 if test $libitm_cv_have_sync_builtins = yes; then
11 AC_DEFINE(HAVE_SYNC_BUILTINS, 1,
12 [Define to 1 if the target supports __sync_*_compare_and_swap])
13 fi])
14
15 dnl Check whether the target supports 64-bit __sync_*_compare_and_swap.
16 AC_DEFUN([LIBITM_CHECK_64BIT_SYNC_BUILTINS], [
17 AC_CACHE_CHECK([whether the target supports 64-bit __sync_*_compare_and_swap],
18 libitm_cv_have_64bit_sync_builtins, [
19 AC_TRY_LINK([#include <stdint.h>],
20 [uint64_t foo, bar;
21 bar = __sync_val_compare_and_swap(&foo, 0, 1);],
22 libitm_cv_have_64bit_sync_builtins=yes,
23 libitm_cv_have_64bit_sync_builtins=no)])
24 if test $libitm_cv_have_64bit_sync_builtins = yes; then
25 AC_DEFINE(HAVE_64BIT_SYNC_BUILTINS, 1,
26 [Define to 1 if the target supports 64-bit __sync_*_compare_and_swap])
27 fi])
28
29 dnl Check whether the target supports hidden visibility.
30 AC_DEFUN([LIBITM_CHECK_ATTRIBUTE_VISIBILITY], [
31 AC_CACHE_CHECK([whether the target supports hidden visibility],
32 libitm_cv_have_attribute_visibility, [
33 save_CFLAGS="$CFLAGS"
34 CFLAGS="$CFLAGS -Werror"
35 AC_TRY_COMPILE([void __attribute__((visibility("hidden"))) foo(void) { }],
36 [], libitm_cv_have_attribute_visibility=yes,
37 libitm_cv_have_attribute_visibility=no)
38 CFLAGS="$save_CFLAGS"])
39 if test $libitm_cv_have_attribute_visibility = yes; then
40 AC_DEFINE(HAVE_ATTRIBUTE_VISIBILITY, 1,
41 [Define to 1 if the target supports __attribute__((visibility(...))).])
42 fi])
43
44 dnl Check whether the target supports dllexport
45 AC_DEFUN([LIBITM_CHECK_ATTRIBUTE_DLLEXPORT], [
46 AC_CACHE_CHECK([whether the target supports dllexport],
47 libitm_cv_have_attribute_dllexport, [
48 save_CFLAGS="$CFLAGS"
49 CFLAGS="$CFLAGS -Werror"
50 AC_TRY_COMPILE([void __attribute__((dllexport)) foo(void) { }],
51 [], libitm_cv_have_attribute_dllexport=yes,
52 libitm_cv_have_attribute_dllexport=no)
53 CFLAGS="$save_CFLAGS"])
54 if test $libitm_cv_have_attribute_dllexport = yes; then
55 AC_DEFINE(HAVE_ATTRIBUTE_DLLEXPORT, 1,
56 [Define to 1 if the target supports __attribute__((dllexport)).])
57 fi])
58
59 dnl Check whether the target supports symbol aliases.
60 AC_DEFUN([LIBITM_CHECK_ATTRIBUTE_ALIAS], [
61 AC_CACHE_CHECK([whether the target supports symbol aliases],
62 libitm_cv_have_attribute_alias, [
63 AC_TRY_LINK([
64 void foo(void) { }
65 extern void bar(void) __attribute__((alias("foo")));],
66 [bar();], libitm_cv_have_attribute_alias=yes, libitm_cv_have_attribute_alias=no)])
67 if test $libitm_cv_have_attribute_alias = yes; then
68 AC_DEFINE(HAVE_ATTRIBUTE_ALIAS, 1,
69 [Define to 1 if the target supports __attribute__((alias(...))).])
70 fi])
71
72 dnl Check how size_t is mangled.
73 AC_DEFUN([LIBITM_CHECK_SIZE_T_MANGLING], [
74 AC_CACHE_CHECK([how size_t is mangled],
75 libitm_cv_size_t_mangling, [
76 AC_TRY_COMPILE([], [extern __SIZE_TYPE__ x; extern unsigned long x;],
77 [libitm_cv_size_t_mangling=m], [
78 AC_TRY_COMPILE([], [extern __SIZE_TYPE__ x; extern unsigned int x;],
79 [libitm_cv_size_t_mangling=j], [
80 AC_TRY_COMPILE([],
81 [extern __SIZE_TYPE__ x; extern unsigned long long x;],
82 [libitm_cv_size_t_mangling=y], [
83 AC_TRY_COMPILE([],
84 [extern __SIZE_TYPE__ x; extern unsigned short x;],
85 [libitm_cv_size_t_mangling=t],
86 [libitm_cv_size_t_mangling=x])
87 ])
88 ])
89 ])
90 ])
91 if test $libitm_cv_size_t_mangling = x; then
92 AC_MSG_ERROR([Unknown underlying type for size_t])
93 fi
94 AC_DEFINE_UNQUOTED(MANGLE_SIZE_T, [$libitm_cv_size_t_mangling],
95 [Define to the letter to which size_t is mangled.])
96 ])
97
98 dnl Check if as supports AVX instructions.
99 AC_DEFUN([LIBITM_CHECK_AS_AVX], [
100 case "${target_cpu}" in
101 i[[34567]]86 | x86_64)
102 AC_CACHE_CHECK([if the assembler supports AVX], libitm_cv_as_avx, [
103 AC_TRY_COMPILE([], [asm("vzeroupper");],
104 [libitm_cv_as_avx=yes], [libitm_cv_as_avx=no])
105 ])
106 if test x$libitm_cv_as_avx = xyes; then
107 AC_DEFINE(HAVE_AS_AVX, 1, [Define to 1 if the assembler supports AVX.])
108 fi
109 ;;
110 esac])
111
112 sinclude(../libtool.m4)
113 dnl The lines below arrange for aclocal not to bring an installed
114 dnl libtool.m4 into aclocal.m4, while still arranging for automake to
115 dnl add a definition of LIBTOOL to Makefile.in.
116 ifelse(,,,[AC_SUBST(LIBTOOL)
117 AC_DEFUN([AM_PROG_LIBTOOL])
118 AC_DEFUN([AC_LIBTOOL_DLOPEN])
119 AC_DEFUN([AC_PROG_LD])
120 ])
121
122 dnl ----------------------------------------------------------------------
123 dnl This whole bit snagged from libstdc++-v3.
124
125 dnl
126 dnl LIBITM_ENABLE
127 dnl (FEATURE, DEFAULT, HELP-ARG, HELP-STRING)
128 dnl (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, permit a|b|c)
129 dnl (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, SHELL-CODE-HANDLER)
130 dnl
131 dnl See docs/html/17_intro/configury.html#enable for documentation.
132 dnl
133 m4_define([LIBITM_ENABLE],[dnl
134 m4_define([_g_switch],[--enable-$1])dnl
135 m4_define([_g_help],[AC_HELP_STRING(_g_switch$3,[$4 @<:@default=$2@:>@])])dnl
136 AC_ARG_ENABLE($1,_g_help,
137 m4_bmatch([$5],
138 [^permit ],
139 [[
140 case "$enableval" in
141 m4_bpatsubst([$5],[permit ])) ;;
142 *) AC_MSG_ERROR(Unknown argument to enable/disable $1) ;;
143 dnl Idea for future: generate a URL pointing to
144 dnl "onlinedocs/configopts.html#whatever"
145 esac
146 ]],
147 [^$],
148 [[
149 case "$enableval" in
150 yes|no) ;;
151 *) AC_MSG_ERROR(Argument to enable/disable $1 must be yes or no) ;;
152 esac
153 ]],
154 [[$5]]),
155 [enable_]m4_bpatsubst([$1],-,_)[=][$2])
156 m4_undefine([_g_switch])dnl
157 m4_undefine([_g_help])dnl
158 ])
159
160
161 dnl
162 dnl If GNU ld is in use, check to see if tricky linker opts can be used. If
163 dnl the native linker is in use, all variables will be defined to something
164 dnl safe (like an empty string).
165 dnl
166 dnl Defines:
167 dnl SECTION_LDFLAGS='-Wl,--gc-sections' if possible
168 dnl OPT_LDFLAGS='-Wl,-O1' if possible
169 dnl LD (as a side effect of testing)
170 dnl Sets:
171 dnl with_gnu_ld
172 dnl libitm_ld_is_gold (possibly)
173 dnl libitm_gnu_ld_version (possibly)
174 dnl
175 dnl The last will be a single integer, e.g., version 1.23.45.0.67.89 will
176 dnl set libitm_gnu_ld_version to 12345. Zeros cause problems.
177 dnl
178 AC_DEFUN([LIBITM_CHECK_LINKER_FEATURES], [
179 # If we're not using GNU ld, then there's no point in even trying these
180 # tests. Check for that first. We should have already tested for gld
181 # by now (in libtool), but require it now just to be safe...
182 test -z "$SECTION_LDFLAGS" && SECTION_LDFLAGS=''
183 test -z "$OPT_LDFLAGS" && OPT_LDFLAGS=''
184 AC_REQUIRE([AC_PROG_LD])
185 AC_REQUIRE([AC_PROG_AWK])
186
187 # The name set by libtool depends on the version of libtool. Shame on us
188 # for depending on an impl detail, but c'est la vie. Older versions used
189 # ac_cv_prog_gnu_ld, but now it's lt_cv_prog_gnu_ld, and is copied back on
190 # top of with_gnu_ld (which is also set by --with-gnu-ld, so that actually
191 # makes sense). We'll test with_gnu_ld everywhere else, so if that isn't
192 # set (hence we're using an older libtool), then set it.
193 if test x${with_gnu_ld+set} != xset; then
194 if test x${ac_cv_prog_gnu_ld+set} != xset; then
195 # We got through "ac_require(ac_prog_ld)" and still not set? Huh?
196 with_gnu_ld=no
197 else
198 with_gnu_ld=$ac_cv_prog_gnu_ld
199 fi
200 fi
201
202 # Start by getting the version number. I think the libtool test already
203 # does some of this, but throws away the result.
204 libitm_ld_is_gold=no
205 if $LD --version 2>/dev/null | grep 'GNU gold'> /dev/null 2>&1; then
206 libitm_ld_is_gold=yes
207 fi
208 changequote(,)
209 ldver=`$LD --version 2>/dev/null |
210 sed -e 's/GNU gold /GNU ld /;s/GNU ld version /GNU ld /;s/GNU ld ([^)]*) /GNU ld /;s/GNU ld \([0-9.][0-9.]*\).*/\1/; q'`
211 changequote([,])
212 libitm_gnu_ld_version=`echo $ldver | \
213 $AWK -F. '{ if (NF<3) [$]3=0; print ([$]1*100+[$]2)*100+[$]3 }'`
214
215 # Set --gc-sections.
216 if test "$with_gnu_ld" = "notbroken"; then
217 # GNU ld it is! Joy and bunny rabbits!
218
219 # All these tests are for C++; save the language and the compiler flags.
220 # Need to do this so that g++ won't try to link in libstdc++
221 ac_test_CFLAGS="${CFLAGS+set}"
222 ac_save_CFLAGS="$CFLAGS"
223 CFLAGS='-x c++ -Wl,--gc-sections'
224
225 # Check for -Wl,--gc-sections
226 # XXX This test is broken at the moment, as symbols required for linking
227 # are now in libsupc++ (not built yet). In addition, this test has
228 # cored on solaris in the past. In addition, --gc-sections doesn't
229 # really work at the moment (keeps on discarding used sections, first
230 # .eh_frame and now some of the glibc sections for iconv).
231 # Bzzzzt. Thanks for playing, maybe next time.
232 AC_MSG_CHECKING([for ld that supports -Wl,--gc-sections])
233 AC_TRY_RUN([
234 int main(void)
235 {
236 try { throw 1; }
237 catch (...) { };
238 return 0;
239 }
240 ], [ac_sectionLDflags=yes],[ac_sectionLDflags=no], [ac_sectionLDflags=yes])
241 if test "$ac_test_CFLAGS" = set; then
242 CFLAGS="$ac_save_CFLAGS"
243 else
244 # this is the suspicious part
245 CFLAGS=''
246 fi
247 if test "$ac_sectionLDflags" = "yes"; then
248 SECTION_LDFLAGS="-Wl,--gc-sections $SECTION_LDFLAGS"
249 fi
250 AC_MSG_RESULT($ac_sectionLDflags)
251 fi
252
253 # Set linker optimization flags.
254 if test x"$with_gnu_ld" = x"yes"; then
255 OPT_LDFLAGS="-Wl,-O1 $OPT_LDFLAGS"
256 fi
257
258 AC_SUBST(SECTION_LDFLAGS)
259 AC_SUBST(OPT_LDFLAGS)
260 ])
261
262
263 dnl
264 dnl Check if the linker used supports linker maps to clear hardware
265 dnl capabilities. This is only supported by Sun ld at the moment.
266 dnl
267 dnl Defines:
268 dnl HWCAP_LDFLAGS='-Wl,-M,clearcap.map' if possible
269 dnl LD (as a side effect of testing)
270 dnl
271 AC_DEFUN([LIBITM_CHECK_LINKER_HWCAP], [
272 test -z "$HWCAP_LDFLAGS" && HWCAP_LDFLAGS=''
273 AC_REQUIRE([AC_PROG_LD])
274
275 ac_save_LDFLAGS="$LDFLAGS"
276 LDFLAGS="$LFLAGS -Wl,-M,$srcdir/clearcap.map"
277
278 AC_MSG_CHECKING([for ld that supports -Wl,-M,mapfile])
279 AC_TRY_LINK([], [return 0;], [ac_hwcap_ldflags=yes],[ac_hwcap_ldflags=no])
280 if test "$ac_hwcap_ldflags" = "yes"; then
281 HWCAP_LDFLAGS="-Wl,-M,$srcdir/clearcap.map $HWCAP_LDFLAGS"
282 fi
283 AC_MSG_RESULT($ac_hwcap_ldflags)
284
285 LDFLAGS="$ac_save_LDFLAGS"
286
287 AC_SUBST(HWCAP_LDFLAGS)
288
289 AM_CONDITIONAL(HAVE_HWCAP, test $ac_hwcap_ldflags != no)
290 ])
291
292
293 dnl
294 dnl Add version tags to symbols in shared library (or not), additionally
295 dnl marking other symbols as private/local (or not).
296 dnl
297 dnl --enable-symvers=style adds a version script to the linker call when
298 dnl creating the shared library. The choice of version script is
299 dnl controlled by 'style'.
300 dnl --disable-symvers does not.
301 dnl + Usage: LIBITM_ENABLE_SYMVERS[(DEFAULT)]
302 dnl Where DEFAULT is either 'yes' or 'no'. Passing `yes' tries to
303 dnl choose a default style based on linker characteristics. Passing
304 dnl 'no' disables versioning.
305 dnl
306 AC_DEFUN([LIBITM_ENABLE_SYMVERS], [
307
308 LIBITM_ENABLE(symvers,yes,[=STYLE],
309 [enables symbol versioning of the shared library],
310 [permit yes|no|gnu*|sun])
311
312 # If we never went through the LIBITM_CHECK_LINKER_FEATURES macro, then we
313 # don't know enough about $LD to do tricks...
314 AC_REQUIRE([LIBITM_CHECK_LINKER_FEATURES])
315
316 # Turn a 'yes' into a suitable default.
317 if test x$enable_symvers = xyes ; then
318 # FIXME The following test is too strict, in theory.
319 if test $enable_shared = no || test "x$LD" = x; then
320 enable_symvers=no
321 else
322 if test $with_gnu_ld = yes ; then
323 enable_symvers=gnu
324 else
325 case ${target_os} in
326 # Sun symbol versioning exists since Solaris 2.5.
327 solaris2.[[5-9]]* | solaris2.1[[0-9]]*)
328 enable_symvers=sun ;;
329 *)
330 enable_symvers=no ;;
331 esac
332 fi
333 fi
334 fi
335
336 # Check if 'sun' was requested on non-Solaris 2 platforms.
337 if test x$enable_symvers = xsun ; then
338 case ${target_os} in
339 solaris2*)
340 # All fine.
341 ;;
342 *)
343 # Unlikely to work.
344 AC_MSG_WARN([=== You have requested Sun symbol versioning, but])
345 AC_MSG_WARN([=== you are not targetting Solaris 2.])
346 AC_MSG_WARN([=== Symbol versioning will be disabled.])
347 enable_symvers=no
348 ;;
349 esac
350 fi
351
352 # Check to see if libgcc_s exists, indicating that shared libgcc is possible.
353 if test $enable_symvers != no; then
354 AC_MSG_CHECKING([for shared libgcc])
355 ac_save_CFLAGS="$CFLAGS"
356 CFLAGS=' -lgcc_s'
357 AC_TRY_LINK(, [return 0;], libitm_shared_libgcc=yes, libitm_shared_libgcc=no)
358 CFLAGS="$ac_save_CFLAGS"
359 if test $libitm_shared_libgcc = no; then
360 cat > conftest.c <<EOF
361 int main (void) { return 0; }
362 EOF
363 changequote(,)dnl
364 libitm_libgcc_s_suffix=`${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
365 -shared -shared-libgcc -o conftest.so \
366 conftest.c -v 2>&1 >/dev/null \
367 | sed -n 's/^.* -lgcc_s\([^ ]*\) .*$/\1/p'`
368 changequote([,])dnl
369 rm -f conftest.c conftest.so
370 if test x${libitm_libgcc_s_suffix+set} = xset; then
371 CFLAGS=" -lgcc_s$libitm_libgcc_s_suffix"
372 AC_TRY_LINK(, [return 0;], libitm_shared_libgcc=yes)
373 CFLAGS="$ac_save_CFLAGS"
374 fi
375 fi
376 AC_MSG_RESULT($libitm_shared_libgcc)
377 fi
378
379 # For GNU ld, we need at least this version. The format is described in
380 # LIBITM_CHECK_LINKER_FEATURES above.
381 libitm_min_gnu_ld_version=21400
382 # XXXXXXXXXXX libitm_gnu_ld_version=21390
383
384 # Check to see if unspecified "yes" value can win, given results above.
385 # Change "yes" into either "no" or a style name.
386 if test $enable_symvers != no && test $libitm_shared_libgcc = yes; then
387 if test $with_gnu_ld = yes; then
388 if test $libitm_gnu_ld_version -ge $libitm_min_gnu_ld_version ; then
389 enable_symvers=gnu
390 elif test $libitm_ld_is_gold = yes ; then
391 enable_symvers=gnu
392 else
393 # The right tools, the right setup, but too old. Fallbacks?
394 AC_MSG_WARN(=== Linker version $libitm_gnu_ld_version is too old for)
395 AC_MSG_WARN(=== full symbol versioning support in this release of GCC.)
396 AC_MSG_WARN(=== You would need to upgrade your binutils to version)
397 AC_MSG_WARN(=== $libitm_min_gnu_ld_version or later and rebuild GCC.)
398 if test $libitm_gnu_ld_version -ge 21200 ; then
399 # Globbing fix is present, proper block support is not.
400 dnl AC_MSG_WARN([=== Dude, you are soooo close. Maybe we can fake it.])
401 dnl enable_symvers=???
402 AC_MSG_WARN([=== Symbol versioning will be disabled.])
403 enable_symvers=no
404 else
405 # 2.11 or older.
406 AC_MSG_WARN([=== Symbol versioning will be disabled.])
407 enable_symvers=no
408 fi
409 fi
410 elif test $enable_symvers = sun; then
411 : All interesting versions of Sun ld support sun style symbol versioning.
412 else
413 # just fail for now
414 AC_MSG_WARN([=== You have requested some kind of symbol versioning, but])
415 AC_MSG_WARN([=== either you are not using a supported linker, or you are])
416 AC_MSG_WARN([=== not building a shared libgcc_s (which is required).])
417 AC_MSG_WARN([=== Symbol versioning will be disabled.])
418 enable_symvers=no
419 fi
420 fi
421
422 AM_CONDITIONAL(LIBITM_BUILD_VERSIONED_SHLIB, test $enable_symvers != no)
423 AM_CONDITIONAL(LIBITM_BUILD_VERSIONED_SHLIB_GNU, test $enable_symvers = gnu)
424 AM_CONDITIONAL(LIBITM_BUILD_VERSIONED_SHLIB_SUN, test $enable_symvers = sun)
425 AC_MSG_NOTICE(versioning on shared library symbols is $enable_symvers)
426 ])