| Message ID | 20240524215746.1212197-1-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add --enable-static-c++-link-check option [BZ #31412] | expand |
* H. J. Lu: > The current minimum GCC version of glibc build is GCC 6.2 or newer. When > building i686 glibc on Fedora 40, GCC 6.4 failed the static C++ link test > since the 32-bit libc.a was built with GCC 14 and has references to > __divmoddi4 which was added to GCC 7. Add --enable-static-c++-link-check > configure option which is on by default. --disable-static-c++-link-check > can be used to disable the static C++ link test. The newly built i686 > libc.a can be used by GCC 6.4 to create static C++ tests. This fixes > BZ #31412. But won't there still be tons of test suite failures? Even CXX=no will not work because in some configurations, it's actually libgcc_s.so.1 that can't be loaded, and that breaks pthread_cancel. Thanks, Florian
On Sat, May 25, 2024 at 2:54 AM Florian Weimer <fweimer@redhat.com> wrote: > > * H. J. Lu: > > > The current minimum GCC version of glibc build is GCC 6.2 or newer. When > > building i686 glibc on Fedora 40, GCC 6.4 failed the static C++ link test > > since the 32-bit libc.a was built with GCC 14 and has references to > > __divmoddi4 which was added to GCC 7. Add --enable-static-c++-link-check > > configure option which is on by default. --disable-static-c++-link-check > > can be used to disable the static C++ link test. The newly built i686 > > libc.a can be used by GCC 6.4 to create static C++ tests. This fixes > > BZ #31412. > > But won't there still be tons of test suite failures? I only saw FAIL: misc/tst-pidfd FAIL: misc/tst-pidfd_getpid with GCC 6.4. I will check if it is a testcase issue. > Even CXX=no will not work because in some configurations, it's actually > libgcc_s.so.1 that can't be loaded, and that breaks pthread_cancel. > c++ still works. Only "c++ -static" doesn't work with the system libc.a.
* H. J. Lu: > On Sat, May 25, 2024 at 2:54 AM Florian Weimer <fweimer@redhat.com> wrote: >> >> * H. J. Lu: >> >> > The current minimum GCC version of glibc build is GCC 6.2 or newer. When >> > building i686 glibc on Fedora 40, GCC 6.4 failed the static C++ link test >> > since the 32-bit libc.a was built with GCC 14 and has references to >> > __divmoddi4 which was added to GCC 7. Add --enable-static-c++-link-check >> > configure option which is on by default. --disable-static-c++-link-check >> > can be used to disable the static C++ link test. The newly built i686 >> > libc.a can be used by GCC 6.4 to create static C++ tests. This fixes >> > BZ #31412. >> >> But won't there still be tons of test suite failures? > > I only saw > > FAIL: misc/tst-pidfd > FAIL: misc/tst-pidfd_getpid > > with GCC 6.4. I will check if it is a testcase issue. > >> Even CXX=no will not work because in some configurations, it's actually >> libgcc_s.so.1 that can't be loaded, and that breaks pthread_cancel. >> > > c++ still works. Only "c++ -static" doesn't work with the system libc.a. I think you'll see the issue if you go back further, to the 2.34 branch. Thanks, Florian
On Sat, May 25, 2024 at 9:08 AM Florian Weimer <fweimer@redhat.com> wrote: > > * H. J. Lu: > > > On Sat, May 25, 2024 at 2:54 AM Florian Weimer <fweimer@redhat.com> wrote: > >> > >> * H. J. Lu: > >> > >> > The current minimum GCC version of glibc build is GCC 6.2 or newer. When > >> > building i686 glibc on Fedora 40, GCC 6.4 failed the static C++ link test > >> > since the 32-bit libc.a was built with GCC 14 and has references to > >> > __divmoddi4 which was added to GCC 7. Add --enable-static-c++-link-check > >> > configure option which is on by default. --disable-static-c++-link-check > >> > can be used to disable the static C++ link test. The newly built i686 > >> > libc.a can be used by GCC 6.4 to create static C++ tests. This fixes > >> > BZ #31412. > >> > >> But won't there still be tons of test suite failures? > > > > I only saw > > > > FAIL: misc/tst-pidfd > > FAIL: misc/tst-pidfd_getpid It is a glibc bug. I submitted a patch: https://patchwork.sourceware.org/project/glibc/list/?series=34355 > > with GCC 6.4. I will check if it is a testcase issue. > > > >> Even CXX=no will not work because in some configurations, it's actually > >> libgcc_s.so.1 that can't be loaded, and that breaks pthread_cancel. > >> > > > > c++ still works. Only "c++ -static" doesn't work with the system libc.a. > > I think you'll see the issue if you go back further, to the 2.34 branch. > I set up LD_LIBRARY_PATH to GCC 6.4 run-time libraries and only saw FAIL: nptl/tst-pthread-gdb-attach FAIL: nptl/tst-pthread-gdb-attach-static which is caused by gdb dependency on GCC 14 run-time libraries. --disable-static-c++-link-check together with --disable-static-c++-tests allow me to test ppc64le glibc on GCC compiler farm.
* H. J. Lu: >> > with GCC 6.4. I will check if it is a testcase issue. >> > >> >> Even CXX=no will not work because in some configurations, it's actually >> >> libgcc_s.so.1 that can't be loaded, and that breaks pthread_cancel. >> >> >> > >> > c++ still works. Only "c++ -static" doesn't work with the system libc.a. >> >> I think you'll see the issue if you go back further, to the 2.34 branch. >> > > I set up LD_LIBRARY_PATH to GCC 6.4 run-time libraries and only saw > > FAIL: nptl/tst-pthread-gdb-attach > FAIL: nptl/tst-pthread-gdb-attach-static > > which is caused by gdb dependency on GCC 14 run-time libraries. > > --disable-static-c++-link-check together with --disable-static-c++-tests > allow me to test ppc64le glibc on GCC compiler farm. Has this GCC 6.4 been built against system glibc? The use case for what you are trying to do seems to be really narrow to me. In general, building a fresh glibc against system glibc will not result in a GCC that is compatible with the (earlier) glibc under development. GCC before 12 probably has it a lot easier. Thanks, Florian
On Sun, May 26, 2024 at 7:08 AM Florian Weimer <fweimer@redhat.com> wrote: > > * H. J. Lu: > > >> > with GCC 6.4. I will check if it is a testcase issue. > >> > > >> >> Even CXX=no will not work because in some configurations, it's actually > >> >> libgcc_s.so.1 that can't be loaded, and that breaks pthread_cancel. > >> >> > >> > > >> > c++ still works. Only "c++ -static" doesn't work with the system libc.a. > >> > >> I think you'll see the issue if you go back further, to the 2.34 branch. > >> > > > > I set up LD_LIBRARY_PATH to GCC 6.4 run-time libraries and only saw > > > > FAIL: nptl/tst-pthread-gdb-attach > > FAIL: nptl/tst-pthread-gdb-attach-static > > > > which is caused by gdb dependency on GCC 14 run-time libraries. > > > > --disable-static-c++-link-check together with --disable-static-c++-tests > > allow me to test ppc64le glibc on GCC compiler farm. > > Has this GCC 6.4 been built against system glibc? No. GCC 6.4 binaries were built years agao. > The use case for what you are trying to do seems to be really narrow to > me. In general, building a fresh glibc against system glibc will not > result in a GCC that is compatible with the (earlier) glibc under > development. GCC before 12 probably has it a lot easier. > I used GCC 6.4 on Fedora 40 to verify that glibc source is buildable with GCC 6 and I discovered a glibc bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31798
diff --git a/configure b/configure index 432e40a592..58e82d792d 100755 --- a/configure +++ b/configure @@ -778,6 +778,7 @@ ac_user_opts=' enable_option_checking with_pkgversion with_bugurl +enable_static_c___link_check with_gd with_gd_include with_gd_lib @@ -1447,6 +1448,8 @@ Optional Features: --disable-option-checking ignore unrecognized --enable/--with options --disable-FEATURE do not include FEATURE (same as --enable-FEATURE=no) --enable-FEATURE[=ARG] include FEATURE [ARG=yes] + --enable-static-c++-link-check + enable static C++ link check [default=yes] --disable-sanity-checks really do not use threads (should not be used except in special situations) [default=yes] --enable-shared build shared library [default=yes if GNU ld] @@ -3810,6 +3813,15 @@ if test -z "$CPP"; then fi +# Check whether --enable-static-c++-link-check was given. +if test ${enable_static_c___link_check+y} +then : + enableval=$enable_static_c___link_check; static_cxx_link_check=$enableval +else $as_nop + static_cxx_link_check=yes +fi + + # We need the C++ compiler only for testing. @@ -4220,10 +4232,11 @@ else $as_nop fi rm -f core conftest.err conftest.$ac_objext conftest.beam \ conftest$ac_exeext conftest.$ac_ext -# Static case. -old_LDFLAGS="$LDFLAGS" -LDFLAGS="$LDFLAGS -static" -cat confdefs.h - <<_ACEOF >conftest.$ac_ext +if test $static_cxx_link_check = yes; then + # Static case. + old_LDFLAGS="$LDFLAGS" + LDFLAGS="$LDFLAGS -static" + cat confdefs.h - <<_ACEOF >conftest.$ac_ext /* end confdefs.h. */ #include <iostream> @@ -4244,7 +4257,8 @@ else $as_nop fi rm -f core conftest.err conftest.$ac_objext conftest.beam \ conftest$ac_exeext conftest.$ac_ext -LDFLAGS="$old_LDFLAGS" + LDFLAGS="$old_LDFLAGS" +fi ac_ext=c ac_cpp='$CPP $CPPFLAGS' ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5' diff --git a/configure.ac b/configure.ac index bdc385d03c..12de4c3d15 100644 --- a/configure.ac +++ b/configure.ac @@ -52,6 +52,12 @@ fi AC_SUBST(cross_compiling) AC_PROG_CPP +AC_ARG_ENABLE([static-c++-link-check], + AS_HELP_STRING([--enable-static-c++-link-check], + [enable static C++ link check @<:@default=yes@:>@]), + [static_cxx_link_check=$enableval], + [static_cxx_link_check=yes]) + # We need the C++ compiler only for testing. AC_PROG_CXX # It's useless to us if it can't link programs (e.g. missing -lstdc++). @@ -61,10 +67,11 @@ AC_LANG_PUSH([C++]) AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])], [libc_cv_cxx_link_ok=yes], [libc_cv_cxx_link_ok=no]) -# Static case. -old_LDFLAGS="$LDFLAGS" -LDFLAGS="$LDFLAGS -static" -AC_LINK_IFELSE([AC_LANG_SOURCE([ +if test $static_cxx_link_check = yes; then + # Static case. + old_LDFLAGS="$LDFLAGS" + LDFLAGS="$LDFLAGS -static" + AC_LINK_IFELSE([AC_LANG_SOURCE([ #include <iostream> int @@ -74,9 +81,10 @@ main() return 0; } ])], - [], - [libc_cv_cxx_link_ok=no]) -LDFLAGS="$old_LDFLAGS" + [], + [libc_cv_cxx_link_ok=no]) + LDFLAGS="$old_LDFLAGS" +fi AC_LANG_POP([C++])]) AS_IF([test $libc_cv_cxx_link_ok != yes], [CXX=])
The current minimum GCC version of glibc build is GCC 6.2 or newer. When building i686 glibc on Fedora 40, GCC 6.4 failed the static C++ link test since the 32-bit libc.a was built with GCC 14 and has references to __divmoddi4 which was added to GCC 7. Add --enable-static-c++-link-check configure option which is on by default. --disable-static-c++-link-check can be used to disable the static C++ link test. The newly built i686 libc.a can be used by GCC 6.4 to create static C++ tests. This fixes BZ #31412. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> --- configure | 24 +++++++++++++++++++----- configure.ac | 22 +++++++++++++++------- 2 files changed, 34 insertions(+), 12 deletions(-)