From fdce86c9f07eb4f95ba438491c2b151e94be7ef2 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Tue, 12 Dec 2023 08:57:02 +0100 Subject: [PATCH] libquadmath: Restore linking against -lm on most targets [PR112963] The r14-4825 change added AC_CHECK_LIBM to libquadmath configure.ac and replaced unconditional linking with -lm with linking with $(LIBM) determined by that. Unfortunately that broke bare metal targets because AC_CHECK_LIBM attempts to link against -lm and this was after (unconditional) GCC_NO_EXECUTABLES. Then r14-4863 partially reverted that change (no longer AC_CHECK_LIBM), but didn't revert the Makefile.am change of -lm to $(LIBM), which had the effect that libquadmath is not linked against -lm on any arch. That is a serious problem though e.g. on Linux, because libquadmath calls a few libm entrypoints and e.g. on powerpc64le the underlinking can cause crashes in IFUNC resolvers of libm. Instead of adding further reversion of the r14-4825 commit and use -lm unconditionally again, this patch adds an AC_CHECK_LIBM like substitutions with the *-ncr-sysv4.3* target handling removed (I think we don't support such targets, especially not in libquadmath) and with the default case replaced by simple using -lm. That is something in between using -lm unconditionally and what AC_CHECK_LIBM does if it would work on bare metal - we know from GCC 13 and earlier that we can link -lm on all targets libquadmath is built for, and just white list a couple of targets which we know don't have separate -lm and don't want to link against that (like Darwin, Cygwin, ...). 2023-12-12 Jakub Jelinek PR libquadmath/112963 * configure.ac (LIBM): Readd AC_CHECK_LIBM-like check without doing AC_CHECK_LIB in it. * configure: Regenerated. * Makefile.in: Regenerated. --- libquadmath/Makefile.in | 1 + libquadmath/configure | 19 +++++++++++++++++-- libquadmath/configure.ac | 14 ++++++++++++++ 3 files changed, 32 insertions(+), 2 deletions(-) diff --git a/libquadmath/Makefile.in b/libquadmath/Makefile.in index dbcafb57e5b..068af559457 100644 --- a/libquadmath/Makefile.in +++ b/libquadmath/Makefile.in @@ -355,6 +355,7 @@ INSTALL_SCRIPT = @INSTALL_SCRIPT@ INSTALL_STRIP_PROGRAM = @INSTALL_STRIP_PROGRAM@ LD = @LD@ LDFLAGS = @LDFLAGS@ +LIBM = @LIBM@ LIBOBJS = @LIBOBJS@ LIBS = @LIBS@ LIBTOOL = @LIBTOOL@ diff --git a/libquadmath/configure b/libquadmath/configure index fd527458285..49d70809218 100755 --- a/libquadmath/configure +++ b/libquadmath/configure @@ -644,6 +644,7 @@ LIBQUAD_USE_SYMVER_GNU_FALSE LIBQUAD_USE_SYMVER_GNU_TRUE LIBQUAD_USE_SYMVER_FALSE LIBQUAD_USE_SYMVER_TRUE +LIBM toolexeclibdir toolexecdir MAINT @@ -10921,7 +10922,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 10924 "configure" +#line 10925 "configure" #include "confdefs.h" #if HAVE_DLFCN_H @@ -11027,7 +11028,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 11030 "configure" +#line 11031 "configure" #include "confdefs.h" #if HAVE_DLFCN_H @@ -12260,6 +12261,20 @@ esac +# AC_CHECK_LIBM variant which avoids AC_CHECK_LIB (that doesn't work +# on bare metal). In the past we've used -lm in Makefile.am unconditionally, +# let's use it there unless target knows it doesn't need that. +LIBM= +case $host in +*-*-beos* | *-*-cegcc* | *-*-cygwin* | *-*-haiku* | *-*-pw32* | *-*-darwin*) + # These system don't have libm, or don't need it + ;; +*) + LIBM=-lm + ;; +esac + + for ac_header in fenv.h langinfo.h locale.h wchar.h wctype.h limits.h ctype.h printf.h errno.h do : as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh` diff --git a/libquadmath/configure.ac b/libquadmath/configure.ac index 23ac3bae6e5..349be2607c6 100644 --- a/libquadmath/configure.ac +++ b/libquadmath/configure.ac @@ -122,6 +122,20 @@ esac AC_SUBST(toolexecdir) AC_SUBST(toolexeclibdir) +# AC_CHECK_LIBM variant which avoids AC_CHECK_LIB (that doesn't work +# on bare metal). In the past we've used -lm in Makefile.am unconditionally, +# let's use it there unless target knows it doesn't need that. +LIBM= +case $host in +*-*-beos* | *-*-cegcc* | *-*-cygwin* | *-*-haiku* | *-*-pw32* | *-*-darwin*) + # These system don't have libm, or don't need it + ;; +*) + LIBM=-lm + ;; +esac +AC_SUBST([LIBM]) + AC_CHECK_HEADERS(fenv.h langinfo.h locale.h wchar.h wctype.h limits.h ctype.h printf.h errno.h) LIBQUAD_CHECK_MATH_H_SIGNGAM