diff options
Diffstat (limited to 'm4/threadlib.m4')
| -rw-r--r-- | m4/threadlib.m4 | 90 |
1 files changed, 84 insertions, 6 deletions
diff --git a/m4/threadlib.m4 b/m4/threadlib.m4 index 1f7b134..ed6ebd5 100644 --- a/m4/threadlib.m4 +++ b/m4/threadlib.m4 @@ -1,4 +1,4 @@ -# threadlib.m4 serial 13 +# threadlib.m4 serial 15 dnl Copyright (C) 2005-2018 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -6,6 +6,8 @@ dnl with or without modifications, as long as this notice is preserved. dnl From Bruno Haible. +AC_PREREQ([2.60]) + dnl gl_THREADLIB dnl ------------ dnl Tests for a multithreading library to be used. @@ -43,11 +45,7 @@ AC_DEFUN([gl_THREADLIB_EARLY_BODY], AC_REQUIRE([AC_CANONICAL_HOST]) dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems. - dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes - dnl AC_GNU_SOURCE. - m4_ifdef([AC_USE_SYSTEM_EXTENSIONS], - [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])], - [AC_REQUIRE([AC_GNU_SOURCE])]) + AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) dnl Check for multithreading. m4_ifdef([gl_THREADLIB_DEFAULT_NO], [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])], @@ -153,6 +151,36 @@ int main () *" -static "*) gl_cv_have_weak=no ;; esac ]) + dnl Check whether the linker supports the --as-needed/--no-as-needed options. + dnl Assume GCC, so that we can use the -Wl option. + AC_CACHE_CHECK([whether the linker supports --as-needed], + [gl_cv_linker_have_as_needed], + [if test -n "$GCC"; then + gl_saved_ldflags="$LDFLAGS" + LDFLAGS="$gl_saved_ldflags -Wl,--as-needed -Wl,--no-as-needed" + AC_LINK_IFELSE([AC_LANG_PROGRAM()], + [gl_cv_linker_have_as_needed=yes], + [gl_cv_linker_have_as_needed=no]) + LDFLAGS="$gl_saved_ldflags" + else + gl_cv_linker_have_as_needed=no + fi + ]) + dnl Check whether the linker supports the --push-state/--pop-state options. + dnl Assume GCC, so that we can use the -Wl option. + AC_CACHE_CHECK([whether the linker supports --push-state], + [gl_cv_linker_have_push_state], + [if test -n "$GCC"; then + gl_saved_ldflags="$LDFLAGS" + LDFLAGS="$gl_saved_ldflags -Wl,--push-state -Wl,--pop-state" + AC_LINK_IFELSE([AC_LANG_PROGRAM()], + [gl_cv_linker_have_push_state=yes], + [gl_cv_linker_have_push_state=no]) + LDFLAGS="$gl_saved_ldflags" + else + gl_cv_linker_have_push_state=no + fi + ]) if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that # it groks <pthread.h>. It's added above, in gl_THREADLIB_EARLY_BODY. @@ -231,6 +259,32 @@ int main () [Define if references to the POSIX multithreading library should be made weak.]) LIBTHREAD= LTLIBTHREAD= + dnl On platforms where GCC enables --as-needed by default, attempt + dnl to make sure that LIBMULTITHREAD really links with -lpthread. + dnl Otherwise linking with LIBMULTITHREAD has no effect; then + dnl the weak symbols are not defined and thus evaluate to NULL. + case "$LIBMULTITHREAD" in + "") ;; + -pthread) + if test $gl_cv_linker_have_as_needed = yes; then + if test $gl_cv_linker_have_push_state = yes; then + LIBMULTITHREAD="$LIBMULTITHREAD -Wl,--push-state -Wl,--no-as-needed -lpthread -Wl,--pop-state" + else + LIBMULTITHREAD="$LIBMULTITHREAD -Wl,--no-as-needed -lpthread" + fi + fi + ;; + *) + if test $gl_cv_linker_have_as_needed = yes; then + if test $gl_cv_linker_have_push_state = yes; then + LIBMULTITHREAD="-Wl,--push-state -Wl,--no-as-needed $LIBMULTITHREAD -Wl,--pop-state" + else + LIBMULTITHREAD="-Wl,--no-as-needed $LIBMULTITHREAD" + fi + fi + ;; + esac + # TODO: May need to modify LTLIBMULTITHREAD similarly. fi fi fi @@ -263,6 +317,18 @@ int main () [Define if references to the old Solaris multithreading library should be made weak.]) LIBTHREAD= LTLIBTHREAD= + dnl On platforms where GCC enables --as-needed by default, attempt + dnl to make sure that LIBMULTITHREAD really links with -lthread. + dnl Otherwise linking with LIBMULTITHREAD has no effect; then + dnl the weak symbols are not defined and thus evaluate to NULL. + if test $gl_cv_linker_have_as_needed = yes; then + if test $gl_cv_linker_have_push_state = yes; then + LIBMULTITHREAD="-Wl,--push-state -Wl,--no-as-needed $LIBMULTITHREAD -Wl,--pop-state" + else + LIBMULTITHREAD="-Wl,--no-as-needed $LIBMULTITHREAD" + fi + fi + # TODO: May need to modify LTLIBMULTITHREAD similarly. fi fi fi @@ -291,6 +357,18 @@ int main () [Define if references to the GNU Pth multithreading library should be made weak.]) LIBTHREAD= LTLIBTHREAD= + dnl On platforms where GCC enables --as-needed by default, attempt + dnl to make sure that LIBMULTITHREAD really links with -lpth. + dnl Otherwise linking with LIBMULTITHREAD has no effect; then + dnl the weak symbols are not defined and thus evaluate to NULL. + if test $gl_cv_linker_have_as_needed = yes; then + if test $gl_cv_linker_have_push_state = yes; then + LIBMULTITHREAD="-Wl,--push-state -Wl,--no-as-needed $LIBMULTITHREAD -Wl,--pop-state" + else + LIBMULTITHREAD="-Wl,--no-as-needed $LIBMULTITHREAD" + fi + fi + # TODO: May need to modify LTLIBMULTITHREAD similarly. fi fi else |