From 759812fddc81c0c131d4633b2a7f56412ce8dbed Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Tue, 28 Jan 2020 13:24:09 +0000 Subject: [PATCH] libstdc++: Replace glibc-specific check for clock_gettime (PR 93325) It's wrong to assume that clock_gettime is unavailable on any *-*-linux* target that doesn't have glibc 2.17 or later. Use a generic test instead of using __GLIBC_PREREQ. Only do that test when is_hosted=yes so that we don't get an error for cross targets without a working linker. This ensures that C library's clock_gettime will be used on non-glibc targets, instead of an incorrect syscall to SYS_clock_gettime. PR libstdc++/93325 * acinclude.m4 (GLIBCXX_ENABLE_LIBSTDCXX_TIME): Use AC_SEARCH_LIBS for clock_gettime instead of explicit glibc version check. * configure: Regenerate. --- libstdc++-v3/ChangeLog | 7 ++++ libstdc++-v3/acinclude.m4 | 22 +++++------- libstdc++-v3/configure | 73 +++++++++++++++++++++++++++++---------- 3 files changed, 70 insertions(+), 32 deletions(-) diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 03061e66333..d75ebbc3662 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -8,6 +8,13 @@ * configure: Regenerate. +2020-01-28 Jonathan Wakely + + PR libstdc++/93325 + * acinclude.m4 (GLIBCXX_ENABLE_LIBSTDCXX_TIME): Use AC_SEARCH_LIBS for + clock_gettime instead of explicit glibc version check. + * configure: Regenerate. + 2020-01-27 Jonathan Wakely PR libstdc++/93426 diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index 39147916e94..ee5e0336f2c 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -1422,20 +1422,14 @@ AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_TIME], [ ac_has_nanosleep=yes ;; gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu) - AC_MSG_CHECKING([for at least GNU libc 2.17]) - AC_TRY_COMPILE( - [#include ], - [ - #if ! __GLIBC_PREREQ(2, 17) - #error - #endif - ], - [glibcxx_glibc217=yes], [glibcxx_glibc217=no]) - AC_MSG_RESULT($glibcxx_glibc217) - - if test x"$glibcxx_glibc217" = x"yes"; then - ac_has_clock_monotonic=yes - ac_has_clock_realtime=yes + # Don't use link test for freestanding library, in case gcc_no_link=yes + if test x"$is_hosted" = xyes; then + # Versions of glibc before 2.17 needed -lrt for clock_gettime. + AC_SEARCH_LIBS(clock_gettime, [rt]) + if test x"$ac_cv_search_clock_gettime" = x"none required"; then + ac_has_clock_monotonic=yes + ac_has_clock_realtime=yes + fi fi ac_has_nanosleep=yes ac_has_sched_yield=yes diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure index 60ad38b47c6..5e2892121f4 100755 --- a/libstdc++-v3/configure +++ b/libstdc++-v3/configure @@ -21072,35 +21072,72 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu ac_has_nanosleep=yes ;; gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu) - { $as_echo "$as_me:${as_lineno-$LINENO}: checking for at least GNU libc 2.17" >&5 -$as_echo_n "checking for at least GNU libc 2.17... " >&6; } - cat confdefs.h - <<_ACEOF >conftest.$ac_ext + # Don't use link test for freestanding library, in case gcc_no_link=yes + if test x"$is_hosted" = xyes; then + # Versions of glibc before 2.17 needed -lrt for clock_gettime. + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing clock_gettime" >&5 +$as_echo_n "checking for library containing clock_gettime... " >&6; } +if ${ac_cv_search_clock_gettime+:} false; then : + $as_echo_n "(cached) " >&6 +else + ac_func_search_save_LIBS=$LIBS +cat confdefs.h - <<_ACEOF >conftest.$ac_ext /* end confdefs.h. */ -#include + +/* Override any GCC internal prototype to avoid an error. + Use char because int might match the return type of a GCC + builtin and then its argument prototype would still apply. */ +#ifdef __cplusplus +extern "C" +#endif +char clock_gettime (); int main () { - - #if ! __GLIBC_PREREQ(2, 17) - #error - #endif - +return clock_gettime (); ; return 0; } _ACEOF -if ac_fn_cxx_try_compile "$LINENO"; then : - glibcxx_glibc217=yes +for ac_lib in '' rt; do + if test -z "$ac_lib"; then + ac_res="none required" + else + ac_res=-l$ac_lib + LIBS="-l$ac_lib $ac_func_search_save_LIBS" + fi + if test x$gcc_no_link = xyes; then + as_fn_error $? "Link tests are not allowed after GCC_NO_EXECUTABLES." "$LINENO" 5 +fi +if ac_fn_cxx_try_link "$LINENO"; then : + ac_cv_search_clock_gettime=$ac_res +fi +rm -f core conftest.err conftest.$ac_objext \ + conftest$ac_exeext + if ${ac_cv_search_clock_gettime+:} false; then : + break +fi +done +if ${ac_cv_search_clock_gettime+:} false; then : + else - glibcxx_glibc217=no + ac_cv_search_clock_gettime=no fi -rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext - { $as_echo "$as_me:${as_lineno-$LINENO}: result: $glibcxx_glibc217" >&5 -$as_echo "$glibcxx_glibc217" >&6; } +rm conftest.$ac_ext +LIBS=$ac_func_search_save_LIBS +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_clock_gettime" >&5 +$as_echo "$ac_cv_search_clock_gettime" >&6; } +ac_res=$ac_cv_search_clock_gettime +if test "$ac_res" != no; then : + test "$ac_res" = "none required" || LIBS="$ac_res $LIBS" - if test x"$glibcxx_glibc217" = x"yes"; then - ac_has_clock_monotonic=yes - ac_has_clock_realtime=yes +fi + + if test x"$ac_cv_search_clock_gettime" = x"none required"; then + ac_has_clock_monotonic=yes + ac_has_clock_realtime=yes + fi fi ac_has_nanosleep=yes ac_has_sched_yield=yes -- 2.30.2