On Mon, Jan 17, 2022 at 3:05 PM David Seifert via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > * `-Werror` can cause issues when a more recent version of GCC compiles > an older version: > - https://bugs.gentoo.org/229059 > - https://bugs.gentoo.org/475350 > - https://bugs.gentoo.org/667104 > --- > libatomic/configure.ac | 6 ++++-- > libbacktrace/configure.ac | 7 ++++--- > libgomp/configure.ac | 6 ++++-- > libitm/configure.ac | 6 ++++-- > libsanitizer/configure.ac | 9 +++++++++ > libsanitizer/libbacktrace/Makefile.am | 2 -- > 6 files changed, 25 insertions(+), 11 deletions(-)
Hi, thanks for the patch, I personally support it (assuming it goes along with a regeneration of the configure scripts). Reading it, though, reminded me of another quibble I had about warning options used when building GCC: The GCC docs for -Wextra say "(This option used to be called -W. The older name is still supported, but the newer name is more descriptive.)" See: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options This to me seems to imply that -Wextra is the preferred name, and that the old name of -W should be replaced by it. Could we also make a change to rename all instances of -W in configure scripts to -Wextra too? Just a thought. Thanks, Eric > > diff --git a/libatomic/configure.ac b/libatomic/configure.ac > index f350b9b3509..5a9f69bb74d 100644 > --- a/libatomic/configure.ac > +++ b/libatomic/configure.ac > @@ -251,10 +251,12 @@ LIBAT_ENABLE_SYMVERS > CFLAGS="$save_CFLAGS" > AC_CACHE_SAVE > > +AC_ARG_ENABLE([werror], [ > + AS_HELP_STRING([--enable-werror], [turns on -Werror @<:@default=yes@:>@])]) > # Add -Wall -Werror if we are using GCC. > -if test "x$GCC" = "xyes"; then > +AS_IF([test "x$enable_werror" != "xno" && test "x$GCC" = "xyes"], [ > XCFLAGS="$XCFLAGS -Wall -Werror" > -fi > +]) > > # Add CET specific flags if CET is enabled > GCC_CET_FLAGS(CET_FLAGS) > diff --git a/libbacktrace/configure.ac b/libbacktrace/configure.ac > index 0dfd82bc03e..a2858e6ecde 100644 > --- a/libbacktrace/configure.ac > +++ b/libbacktrace/configure.ac > @@ -145,10 +145,11 @@ ACX_PROG_CC_WARNING_OPTS([-W -Wall -Wwrite-strings > -Wstrict-prototypes \ > -Wmissing-format-attribute -Wcast-qual], > [WARN_FLAGS]) > > -if test -n "${with_target_subdir}"; then > +AC_ARG_ENABLE([werror], [ > + AS_HELP_STRING([--enable-werror], [turns on -Werror @<:@default=yes@:>@])]) > +AS_IF([test "x$enable_werror" != "xno" && test -n "${with_target_subdir}"], [ > WARN_FLAGS="$WARN_FLAGS -Werror" > -fi > - > +]) > AC_SUBST(WARN_FLAGS) > > if test -n "${with_target_subdir}"; then > diff --git a/libgomp/configure.ac b/libgomp/configure.ac > index bfb613b91f0..c3062dc5a07 100644 > --- a/libgomp/configure.ac > +++ b/libgomp/configure.ac > @@ -121,10 +121,12 @@ AC_SUBST(CFLAGS) > # in both places for now and restore CFLAGS at the end of config. > save_CFLAGS="$CFLAGS" > > +AC_ARG_ENABLE([werror], [ > + AS_HELP_STRING([--enable-werror], [turns on -Werror @<:@default=yes@:>@])]) > # Add -Wall -Werror if we are using GCC. > -if test "x$GCC" = "xyes"; then > +AS_IF([test "x$enable_werror" != "xno" && test "x$GCC" = "xyes"], [ > XCFLAGS="$XCFLAGS -Wall -Werror" > -fi > +]) > > # Find other programs we need. > AC_CHECK_TOOL(AR, ar) > diff --git a/libitm/configure.ac b/libitm/configure.ac > index ac81b146845..ad99d14098e 100644 > --- a/libitm/configure.ac > +++ b/libitm/configure.ac > @@ -261,10 +261,12 @@ GCC_CHECK_ELF_STYLE_WEAKREF > CFLAGS="$save_CFLAGS" > AC_CACHE_SAVE > > +AC_ARG_ENABLE([werror], [ > + AS_HELP_STRING([--enable-werror], [turns on -Werror @<:@default=yes@:>@])]) > # Add -Wall -Werror if we are using GCC. > -if test "x$GCC" = "xyes"; then > +AS_IF([test "x$enable_werror" != "xno" && test "x$GCC" = "xyes"], [ > XCFLAGS="$XCFLAGS -Wall -Werror" > -fi > +]) > > XCFLAGS="$XCFLAGS $XPCFLAGS" > > diff --git a/libsanitizer/configure.ac b/libsanitizer/configure.ac > index 13cd302030d..64eb42afc83 100644 > --- a/libsanitizer/configure.ac > +++ b/libsanitizer/configure.ac > @@ -400,6 +400,15 @@ fi > AC_SUBST([TSAN_TARGET_DEPENDENT_OBJECTS]) > AC_SUBST([SANITIZER_COMMON_TARGET_DEPENDENT_OBJECTS]) > > +AC_ARG_ENABLE([werror], [ > + AS_HELP_STRING([--enable-werror], [turns on -Werror @<:@default=yes@:>@])]) > + > +WARN_FLAGS="-W -Wall -Wwrite-strings -Wmissing-format-attribute -Wcast-qual" > +AS_IF([test "x$enable_werror" != "xno"], [ > + WARN_FLAGS="$WARN_FLAGS -Werror" > +]) > +AC_SUBST([WARN_FLAGS]) > + > # Determine what GCC version number to use in filesystem paths. > GCC_BASE_VER > > diff --git a/libsanitizer/libbacktrace/Makefile.am > b/libsanitizer/libbacktrace/Makefile.am > index 16accd468df..0cf8d2104c0 100644 > --- a/libsanitizer/libbacktrace/Makefile.am > +++ b/libsanitizer/libbacktrace/Makefile.am > @@ -34,8 +34,6 @@ ACLOCAL_AMFLAGS = -I ../.. -I ../../config > AM_CPPFLAGS = -I $(top_srcdir)/../include -I $(top_srcdir)/../libgcc \ > -I ../../libgcc -I .. -I $(top_srcdir) -I > $(top_srcdir)/../libbacktrace > > -WARN_FLAGS = -W -Wall -Wwrite-strings -Wmissing-format-attribute \ > - -Wcast-qual -Werror > C_WARN_FLAGS = $(WARN_FLAGS) -Wstrict-prototypes -Wmissing-prototypes > -Wold-style-definition > CXX_WARN_FLAGS = $(WARN_FLAGS) -Wno-unused-parameter > AM_CFLAGS = $(C_WARN_FLAGS) > -- > 2.34.1 >
