| Message ID | 20230823160322.237140-1-jwakely@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC] libstdc++: Make --enable-libstdcxx-backtrace=auto default to yes | expand |
On Wed, 23 Aug 2023 at 17:03, Jonathan Wakely via Libstdc++ <libstdc++@gcc.gnu.org> wrote: > > Any objections to this? It's a C++23 feture, so should be enabled by > default. I've pushed this to trunk, so let's see what breaks! > > -- >8 -- > > This causes libstdc++_libbacktrace.a to be built by default. This might > fail on some targets, in which case we can make the 'auto' choice expand > to either 'yes' or 'no' depending on the target. > > libstdc++-v3/ChangeLog: > > * acinclude.m4 (GLIBCXX_ENABLE_BACKTRACE): Default to yes. > * configure: Regenerate. > --- > libstdc++-v3/acinclude.m4 | 2 +- > libstdc++-v3/configure | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 > index b25378eaace..50c808c6b2d 100644 > --- a/libstdc++-v3/acinclude.m4 > +++ b/libstdc++-v3/acinclude.m4 > @@ -5481,7 +5481,7 @@ BACKTRACE_CPPFLAGS="$BACKTRACE_CPPFLAGS -DBACKTRACE_ELF_SIZE=$elfsize" > > AC_MSG_CHECKING([whether to build libbacktrace support]) > if test "$enable_libstdcxx_backtrace" = "auto"; then > - enable_libstdcxx_backtrace=no > + enable_libstdcxx_backtrace=yes > fi > AC_MSG_RESULT($enable_libstdcxx_backtrace) > if test "$enable_libstdcxx_backtrace" = "yes"; then >
On Fri, 1 Sept 2023 at 12:16, Jonathan Wakely <jwakely@redhat.com> wrote: > > On Wed, 23 Aug 2023 at 17:03, Jonathan Wakely via Libstdc++ > <libstdc++@gcc.gnu.org> wrote: > > > > Any objections to this? It's a C++23 feture, so should be enabled by > > default. > > I've pushed this to trunk, so let's see what breaks! This modules header broke on aarch64, of course: FAIL: g++.dg/modules/xtreme-header_b.C -std=c++2b (test for excess errors) > > > > > > -- >8 -- > > > > This causes libstdc++_libbacktrace.a to be built by default. This might > > fail on some targets, in which case we can make the 'auto' choice expand > > to either 'yes' or 'no' depending on the target. > > > > libstdc++-v3/ChangeLog: > > > > * acinclude.m4 (GLIBCXX_ENABLE_BACKTRACE): Default to yes. > > * configure: Regenerate. > > --- > > libstdc++-v3/acinclude.m4 | 2 +- > > libstdc++-v3/configure | 2 +- > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 > > index b25378eaace..50c808c6b2d 100644 > > --- a/libstdc++-v3/acinclude.m4 > > +++ b/libstdc++-v3/acinclude.m4 > > @@ -5481,7 +5481,7 @@ BACKTRACE_CPPFLAGS="$BACKTRACE_CPPFLAGS -DBACKTRACE_ELF_SIZE=$elfsize" > > > > AC_MSG_CHECKING([whether to build libbacktrace support]) > > if test "$enable_libstdcxx_backtrace" = "auto"; then > > - enable_libstdcxx_backtrace=no > > + enable_libstdcxx_backtrace=yes > > fi > > AC_MSG_RESULT($enable_libstdcxx_backtrace) > > if test "$enable_libstdcxx_backtrace" = "yes"; then > >
I was about to enter a PR for the regression, but as you're already aware, I'll wait 24 hours to see if this magically goes away. :] > On Fri, 1 Sept 2023 at 12:16, Jonathan Wakely <jwakely@redhat.com> wrote: > > > > On Wed, 23 Aug 2023 at 17:03, Jonathan Wakely via Libstdc++ > > <libstdc++@gcc.gnu.org> wrote: > > > > > > Any objections to this? It's a C++23 feture, so should be enabled by > > > default. > > > > I've pushed this to trunk, so let's see what breaks! > > This modules header broke on aarch64, of course: > FAIL: g++.dg/modules/xtreme-header_b.C -std=c++2b (test for excess errors) And others, according to testresults@ including powerpc64le-unknown-linux-gnu, x86_64-pc-linux-gnu, s390x-ibm-linux-gnu, m68k-unknown-linux-gnu, pru-unknown-elf, and...cris-elf (notably, both "64-bit" and "32-bit" configurations). Not sure how much information you have, but for cris-elf, g++.log shows: FAIL: g++.dg/modules/xtreme-header_b.C -std=c++2b (test for excess errors) Excess errors: /obj/libstdc++-v3/include/stacktrace:202:24: error: mangling of 'constexpr std::stacktrace_entry::_M_get_info(std::string*, std::string*, int*) const::<lambda(void*, std::stacktrace_entry::uintptr_t, const char*, std::stacktrace_entry::uintptr_t, std::stacktrace_entry::uintptr_t)>::operator void (*)(void*, std::stacktrace_entry::uintptr_t, const char*, std::stacktrace_entry::uintptr_t, std::stacktrace_entry::uintptr_t)() const' as '_ZZNKSt16stacktrace_entry11_M_get_infoEPNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES6_PiENKUlPvmPKcmmE_cvPFvS8_mSA_mmEEv' conflicts with a previous mangle /obj/libstdc++-v3/include/stacktrace:202:24: error: mangling of 'static constexpr void std::stacktrace_entry::_M_get_info(std::string*, std::string*, int*) const::<lambda(void*, std::stacktrace_entry::uintptr_t, const char*, std::stacktrace_entry::uintptr_t, std::stacktrace_entry::uintptr_t)>::_FUN(void*, std::stacktrace_entry::uintptr_t, const char*, std::stacktrace_entry::uintptr_t, std::stacktrace_entry::uintptr_t)' as '_ZZNKSt16stacktrace_entry11_M_get_infoEPNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES6_PiENUlPvmPKcmmE_4_FUNES8_mSA_mm' conflicts with a previous mangle /obj/libstdc++-v3/include/stacktrace:202:24: error: mangling of 'std::stacktrace_entry::_M_get_info(std::string*, std::string*, int*) const::<lambda(void*, std::stacktrace_entry::uintptr_t, const char*, std::stacktrace_entry::uintptr_t, std::stacktrace_entry::uintptr_t)>' as '_ZZNKSt16stacktrace_entry11_M_get_infoEPNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES6_PiENKUlPvmPKcmmE_clES8_mSA_mm' conflicts with a previous mangle So, I *guess* it's some kind of pre-existing mangling foulup with C++20 in the backtrace-support that just happens to be ticked off by the module testsuite. But you probably already knew that. brgds, H-P
> Date: Fri, 1 Sep 2023 12:16:40 +0100 > Reply-To: Jonathan Wakely <jwakely@redhat.com> > > On Wed, 23 Aug 2023 at 17:03, Jonathan Wakely via Libstdc++ > <libstdc++@gcc.gnu.org> wrote: > > > > Any objections to this? It's a C++23 feture, so should be enabled by > > default. > > I've pushed this to trunk, so let's see what breaks! > > > > > > -- >8 -- > > > > This causes libstdc++_libbacktrace.a to be built by default. This might > > fail on some targets, in which case we can make the 'auto' choice expand > > to either 'yes' or 'no' depending on the target. > > > > libstdc++-v3/ChangeLog: > > > > * acinclude.m4 (GLIBCXX_ENABLE_BACKTRACE): Default to yes. > > * configure: Regenerate. Incidentally, should check_effective_target_stacktrace in libstdc++.exp also be adjusted to match; removing the _GLIBCXX_HOSTED condition? brgds, H-P
On Mon, 4 Sept 2023 at 17:47, Hans-Peter Nilsson via Libstdc++ <libstdc++@gcc.gnu.org> wrote: > > > Date: Fri, 1 Sep 2023 12:16:40 +0100 > > Reply-To: Jonathan Wakely <jwakely@redhat.com> > > > > On Wed, 23 Aug 2023 at 17:03, Jonathan Wakely via Libstdc++ > > <libstdc++@gcc.gnu.org> wrote: > > > > > > Any objections to this? It's a C++23 feture, so should be enabled by > > > default. > > > > I've pushed this to trunk, so let's see what breaks! > > > > > > > > > > -- >8 -- > > > > > > This causes libstdc++_libbacktrace.a to be built by default. This might > > > fail on some targets, in which case we can make the 'auto' choice expand > > > to either 'yes' or 'no' depending on the target. > > > > > > libstdc++-v3/ChangeLog: > > > > > > * acinclude.m4 (GLIBCXX_ENABLE_BACKTRACE): Default to yes. > > > * configure: Regenerate. > > Incidentally, should check_effective_target_stacktrace in > libstdc++.exp also be adjusted to match; removing the > _GLIBCXX_HOSTED condition? No, it should still depend on is_hosted. The acinclude.m4 macro should check that.
On Mon, 4 Sept 2023 at 17:49, Jonathan Wakely <jwakely.gcc@gmail.com> wrote: > > On Mon, 4 Sept 2023 at 17:47, Hans-Peter Nilsson via Libstdc++ > <libstdc++@gcc.gnu.org> wrote: > > > > > Date: Fri, 1 Sep 2023 12:16:40 +0100 > > > Reply-To: Jonathan Wakely <jwakely@redhat.com> > > > > > > On Wed, 23 Aug 2023 at 17:03, Jonathan Wakely via Libstdc++ > > > <libstdc++@gcc.gnu.org> wrote: > > > > > > > > Any objections to this? It's a C++23 feture, so should be enabled by > > > > default. > > > > > > I've pushed this to trunk, so let's see what breaks! > > > > > > > > > > > > > > -- >8 -- > > > > > > > > This causes libstdc++_libbacktrace.a to be built by default. This might > > > > fail on some targets, in which case we can make the 'auto' choice expand > > > > to either 'yes' or 'no' depending on the target. > > > > > > > > libstdc++-v3/ChangeLog: > > > > > > > > * acinclude.m4 (GLIBCXX_ENABLE_BACKTRACE): Default to yes. > > > > * configure: Regenerate. > > > > Incidentally, should check_effective_target_stacktrace in > > libstdc++.exp also be adjusted to match; removing the > > _GLIBCXX_HOSTED condition? > > No, it should still depend on is_hosted. The acinclude.m4 macro should > check that. Done in r14-3761-g6de5f5a4fe85bd
> From: Jonathan Wakely <jwakely@redhat.com> > Date: Wed, 6 Sep 2023 23:30:08 +0100 > On Mon, 4 Sept 2023 at 17:49, Jonathan Wakely <jwakely.gcc@gmail.com> wrote: > > > > On Mon, 4 Sept 2023 at 17:47, Hans-Peter Nilsson via Libstdc++ > > <libstdc++@gcc.gnu.org> wrote: > > > > > > > Date: Fri, 1 Sep 2023 12:16:40 +0100 > > > > Reply-To: Jonathan Wakely <jwakely@redhat.com> > > > > > > > > On Wed, 23 Aug 2023 at 17:03, Jonathan Wakely via Libstdc++ > > > > <libstdc++@gcc.gnu.org> wrote: > > > > > > > > > > Any objections to this? It's a C++23 feture, so should be enabled by > > > > > default. > > > > > > > > I've pushed this to trunk, so let's see what breaks! > > > > > > > > > > > > > > > > > > -- >8 -- > > > > > > > > > > This causes libstdc++_libbacktrace.a to be built by default. This might > > > > > fail on some targets, in which case we can make the 'auto' choice expand > > > > > to either 'yes' or 'no' depending on the target. > > > > > > > > > > libstdc++-v3/ChangeLog: > > > > > > > > > > * acinclude.m4 (GLIBCXX_ENABLE_BACKTRACE): Default to yes. > > > > > * configure: Regenerate. > > > > > > Incidentally, should check_effective_target_stacktrace in > > > libstdc++.exp also be adjusted to match; removing the > > > _GLIBCXX_HOSTED condition? > > > > No, it should still depend on is_hosted. The acinclude.m4 macro should > > check that. > > Done in r14-3761-g6de5f5a4fe85bd Aha, that's what you meant. I thought you meant that just check_effective_target_stacktrace should be gated on $is_hosted. Yeah, it makes sense not to have backtrace enabled by default for ! $is_hosted. On the other hand, bare-iron targets like cris-elf apparently *are* hosted, according to "#if __STDC_HOSTED__". I guess I'll have to dig into what the definition of "hosted" is, because I don't agree by the layman obvious definition. Maybe there's a bug to fix. There sure are many yaks to shave these days. brgds, H-P
On Thu, 7 Sept 2023 at 00:09, Hans-Peter Nilsson <hp@axis.com> wrote: > > > From: Jonathan Wakely <jwakely@redhat.com> > > Date: Wed, 6 Sep 2023 23:30:08 +0100 > > > On Mon, 4 Sept 2023 at 17:49, Jonathan Wakely <jwakely.gcc@gmail.com> wrote: > > > > > > On Mon, 4 Sept 2023 at 17:47, Hans-Peter Nilsson via Libstdc++ > > > <libstdc++@gcc.gnu.org> wrote: > > > > > > > > > Date: Fri, 1 Sep 2023 12:16:40 +0100 > > > > > Reply-To: Jonathan Wakely <jwakely@redhat.com> > > > > > > > > > > On Wed, 23 Aug 2023 at 17:03, Jonathan Wakely via Libstdc++ > > > > > <libstdc++@gcc.gnu.org> wrote: > > > > > > > > > > > > Any objections to this? It's a C++23 feture, so should be enabled by > > > > > > default. > > > > > > > > > > I've pushed this to trunk, so let's see what breaks! > > > > > > > > > > > > > > > > > > > > > > -- >8 -- > > > > > > > > > > > > This causes libstdc++_libbacktrace.a to be built by default. This might > > > > > > fail on some targets, in which case we can make the 'auto' choice expand > > > > > > to either 'yes' or 'no' depending on the target. > > > > > > > > > > > > libstdc++-v3/ChangeLog: > > > > > > > > > > > > * acinclude.m4 (GLIBCXX_ENABLE_BACKTRACE): Default to yes. > > > > > > * configure: Regenerate. > > > > > > > > Incidentally, should check_effective_target_stacktrace in > > > > libstdc++.exp also be adjusted to match; removing the > > > > _GLIBCXX_HOSTED condition? > > > > > > No, it should still depend on is_hosted. The acinclude.m4 macro should > > > check that. > > > > Done in r14-3761-g6de5f5a4fe85bd > > Aha, that's what you meant. I thought you meant that just > check_effective_target_stacktrace should be gated on > $is_hosted. > > Yeah, it makes sense not to have backtrace enabled by > default for ! $is_hosted. On the other hand, bare-iron > targets like cris-elf apparently *are* hosted, according to > "#if __STDC_HOSTED__". I guess I'll have to dig into what > the definition of "hosted" is, because I don't agree by the > layman obvious definition. Maybe there's a bug to fix. I don't think there's a bug. $is_hosted is true for --enable-hosted-libstdcxx which is on by default. > There sure are many yaks to shave these days. > > brgds, H-P >
On Thu, 7 Sept 2023 at 00:10, Jonathan Wakely <jwakely@redhat.com> wrote: > > On Thu, 7 Sept 2023 at 00:09, Hans-Peter Nilsson <hp@axis.com> wrote: > > > > > From: Jonathan Wakely <jwakely@redhat.com> > > > Date: Wed, 6 Sep 2023 23:30:08 +0100 > > > > > On Mon, 4 Sept 2023 at 17:49, Jonathan Wakely <jwakely.gcc@gmail.com> wrote: > > > > > > > > On Mon, 4 Sept 2023 at 17:47, Hans-Peter Nilsson via Libstdc++ > > > > <libstdc++@gcc.gnu.org> wrote: > > > > > > > > > > > Date: Fri, 1 Sep 2023 12:16:40 +0100 > > > > > > Reply-To: Jonathan Wakely <jwakely@redhat.com> > > > > > > > > > > > > On Wed, 23 Aug 2023 at 17:03, Jonathan Wakely via Libstdc++ > > > > > > <libstdc++@gcc.gnu.org> wrote: > > > > > > > > > > > > > > Any objections to this? It's a C++23 feture, so should be enabled by > > > > > > > default. > > > > > > > > > > > > I've pushed this to trunk, so let's see what breaks! > > > > > > > > > > > > > > > > > > > > > > > > > > -- >8 -- > > > > > > > > > > > > > > This causes libstdc++_libbacktrace.a to be built by default. This might > > > > > > > fail on some targets, in which case we can make the 'auto' choice expand > > > > > > > to either 'yes' or 'no' depending on the target. > > > > > > > > > > > > > > libstdc++-v3/ChangeLog: > > > > > > > > > > > > > > * acinclude.m4 (GLIBCXX_ENABLE_BACKTRACE): Default to yes. > > > > > > > * configure: Regenerate. > > > > > > > > > > Incidentally, should check_effective_target_stacktrace in > > > > > libstdc++.exp also be adjusted to match; removing the > > > > > _GLIBCXX_HOSTED condition? > > > > > > > > No, it should still depend on is_hosted. The acinclude.m4 macro should > > > > check that. > > > > > > Done in r14-3761-g6de5f5a4fe85bd > > > > Aha, that's what you meant. I thought you meant that just > > check_effective_target_stacktrace should be gated on > > $is_hosted. > > > > Yeah, it makes sense not to have backtrace enabled by > > default for ! $is_hosted. On the other hand, bare-iron > > targets like cris-elf apparently *are* hosted, according to > > "#if __STDC_HOSTED__". I guess I'll have to dig into what > > the definition of "hosted" is, because I don't agree by the > > layman obvious definition. Maybe there's a bug to fix. > > I don't think there's a bug. $is_hosted is true for > --enable-hosted-libstdcxx which is on by default. And IIRC __STDC_HOSTED__ is defined unless you compile with -ffreestanding. > > > There sure are many yaks to shave these days. > > > > brgds, H-P > >
> Date: Thu, 7 Sep 2023 00:11:04 +0100 > From: Jonathan Wakely via Gcc-patches <gcc-patches@gcc.gnu.org> > On Thu, 7 Sept 2023 at 00:10, Jonathan Wakely <jwakely@redhat.com> wrote: > > I don't think there's a bug. $is_hosted is true for > > --enable-hosted-libstdcxx which is on by default. > > And IIRC __STDC_HOSTED__ is defined unless you compile with -ffreestanding. Also documented and thus fine by any (reasonable) definition :) no need for anyone (me) to guess. brgds, H-P
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index b25378eaace..50c808c6b2d 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -5481,7 +5481,7 @@ BACKTRACE_CPPFLAGS="$BACKTRACE_CPPFLAGS -DBACKTRACE_ELF_SIZE=$elfsize" AC_MSG_CHECKING([whether to build libbacktrace support]) if test "$enable_libstdcxx_backtrace" = "auto"; then - enable_libstdcxx_backtrace=no + enable_libstdcxx_backtrace=yes fi AC_MSG_RESULT($enable_libstdcxx_backtrace) if test "$enable_libstdcxx_backtrace" = "yes"; then