On Wed, Oct 9, 2024 at 4:54 AM Christophe Lyon <christophe.l...@linaro.org> wrote: > > On Wed, 9 Oct 2024 at 03:05, Eric Gallager <eg...@gwmail.gwu.edu> wrote: > > > > On Tue, Oct 8, 2024 at 6:25 AM Richard Sandiford > > <richard.sandif...@arm.com> wrote: > > > > > > Christophe Lyon <christophe.l...@linaro.org> writes: > > > > When --enable-werror is enabled when running the top-level configure, > > > > it passes --enable-werror-always to subdirs. Some of them, like > > > > libgcc, ignore it. > > > > > > > > This patch adds support for it, enabled only for aarch64, to avoid > > > > breaking bootstrap for other targets. > > > > > > > > The patch also adds -Wno-prio-ctor-dtor to avoid a warning when > > > > compiling lse_init.c > > > > > > > > libgcc/ > > > > * Makefile.in (WERROR): New. > > > > * config/aarch64/t-aarch64: Handle WERROR. Always use > > > > -Wno-prio-ctor-dtor. > > > > * configure.ac: Add support for --enable-werror-always. > > > > * configure: Regenerate. > > > > --- > > > > libgcc/Makefile.in | 1 + > > > > libgcc/config/aarch64/t-aarch64 | 1 + > > > > libgcc/configure | 31 +++++++++++++++++++++++++++++++ > > > > libgcc/configure.ac | 5 +++++ > > > > 4 files changed, 38 insertions(+) > > > > > > > > [...] > > > > diff --git a/libgcc/configure.ac b/libgcc/configure.ac > > > > index 4e8c036990f..6b3ea2aea5c 100644 > > > > --- a/libgcc/configure.ac > > > > +++ b/libgcc/configure.ac > > > > @@ -13,6 +13,7 @@ sinclude(../config/unwind_ipinfo.m4) > > > > sinclude(../config/gthr.m4) > > > > sinclude(../config/sjlj.m4) > > > > sinclude(../config/cet.m4) > > > > +sinclude(../config/warnings.m4) > > > > > > > > AC_INIT([GNU C Runtime Library], 1.0,,[libgcc]) > > > > AC_CONFIG_SRCDIR([static-object.mk]) > > > > @@ -746,6 +747,10 @@ AC_SUBST(HAVE_STRUB_SUPPORT) > > > > # Determine what GCC version number to use in filesystem paths. > > > > GCC_BASE_VER > > > > > > > > +# Only enable with --enable-werror-always until existing warnings are > > > > +# corrected. > > > > +ACX_PROG_CC_WARNINGS_ARE_ERRORS([manual]) > > > > > > It looks like this is borrowed from libcpp and/or libdecnumber. > > > Those are a bit different from libgcc in that they're host libraries > > > that can be built with any supported compiler (including non-GCC ones). > > > In constrast, libgcc can only be built with the corresponding version > > > of GCC. The usual restrictions on -Werror -- only use it during stages > > > 2 and 3, or if the user explicitly passes --enable-werror -- don't apply > > > in libgcc's case. We should always be building with the "right" version > > > of GCC (even for Canadian crosses) and so should always be able to use > > > -Werror. > > > > > > So personally, I think we should just go with: > > > > > > diff --git a/libgcc/config/aarch64/t-aarch64 > > > b/libgcc/config/aarch64/t-aarch64 > > > index b70e7b94edd..ae1588ce307 100644 > > > --- a/libgcc/config/aarch64/t-aarch64 > > > +++ b/libgcc/config/aarch64/t-aarch64 > > > @@ -30,3 +30,4 @@ LIB2ADDEH += \ > > > $(srcdir)/config/aarch64/__arm_za_disable.S > > > > > > SHLIB_MAPFILES += $(srcdir)/config/aarch64/libgcc-sme.ver > > > +LIBGCC2_CFLAGS += $(WERROR) -Wno-prio-ctor-dtor > > > > > > ...this, but with $(WERROR) replaced by -Werror. > > > > > > At least, it would be a good way of finding out if there's a case > > > I've forgotten :) > > > > > > Let's see what others think though. > > > > I think it would be worthwhile to test this assumption first; I have a > > vague memory of having seen warnings in libgcc previously that would > > presumably get turned into errors if -Werror were applied > > unconditionally... > > > Sorry, it's not clear to me what you mean by "test this assumption" ? > Do you mean I should push the patch with unconditional -Werror and > monitor what happens for a while? > Or investigate more / other targets? > Or wait for others to commit? >
I mean, I think we should try the original approach of having it be enableable manually first, let some people test by enabling it manually, and then if they all report back success, then we can go ahead with the unconditional -Werror version of it. > Thanks, > > Christophe > > > > > > > Thanks, > > > Richard
