Re: [libvirt] [PATCH] Use gnulib's manywarnings & warnings modules

On 04/01/2011 09:39 AM, Daniel P. Berrange wrote: > > * acinclude.m4: Rewrite to use gl_WARN_ADD and gl_MANYWARN_ALL_GCC > * bootstrap.conf: Add warnings & manywarnings > * configure.ac: Switch to gl_WARN_ADD > * m4/compiler-flags.m4: Obsoleted by gl_WARN_ADD > --- > acinclude.m4 | 153 ++++++++++++++++++++++++++------------------------ I really don't like how we have crammed so much into acinclude.m4; it would be nicer if we could separate things into individual m4/foo.m4 files...

> + # List of warnings that are not relevant / wanted > + dontwarn="$dontwarn -Wc++-compat" # Don't care about C++ compiler compat > + dontwarn="$dontwarn -Wtraditional" # Don't care about ancient C standard compat > + dontwarn="$dontwarn -Wtraditional-conversion" # Don't care about ancient C standard compat > + dontwarn="$dontwarn -Wsystem-headers" # Ignore warnings in /usr/include > + dontwarn="$dontwarn -Wpadded" # Happy for compiler to add struct padding > + dontwarn="$dontwarn -Wunreachable-code" # GCC very confused with -O2 > + dontwarn="$dontwarn -Wconversion" # Too many to deal with > + dontwarn="$dontwarn -Wsign-conversion" # Too many to deal with > + dontwarn="$dontwarn -Wvla" # GNULIB gettext.h violates > + dontwarn="$dontwarn -Wundef" # Many GNULIB violations We really ought to follow coreutils' lead of generating two separate lists of -W flags - a larger set for libvirt and a smaller set for gnulib. Then exemptions such as -Wvla could be used just for gnulib. But that can be a followup patch.

> + dontwarn="$dontwarn -Wcast-qual" # Need to allow bad cast for execve() > + dontwarn="$dontwarn -Wlong-long" # We need to use long long in many places > + > + # We might fundamentally need some of these disabled forever, but ideally > + # we'd turn many of them on > + dontwarn="$dontwarn -Wformat-nonliteral" > + dontwarn="$dontwarn -Wswitch-default" > + dontwarn="$dontwarn -Wswitch-enum" > + dontwarn="$dontwarn -Wstrict-overflow" > + dontwarn="$dontwarn -Wfloat-equal" > + dontwarn="$dontwarn -Wdeclaration-after-statement" > + dontwarn="$dontwarn -Wunsafe-loop-optimizations" > + dontwarn="$dontwarn -Wcast-qual" > + dontwarn="$dontwarn -Wconversion" > + dontwarn="$dontwarn -Wsign-conversion" > + dontwarn="$dontwarn -Wold-style-definition" > + dontwarn="$dontwarn -Wmissing-noreturn" > + dontwarn="$dontwarn -Wpacked" > + dontwarn="$dontwarn -Wunused-macros" > + dontwarn="$dontwarn -W" -W is the same as -Wextra - that turns on a lot of useful warnings. Can we fine-tune it to just disable the needed warnings?

> + dontwarn="$dontwarn -Woverlength-strings" > + dontwarn="$dontwarn -Wmissing-format-attribute" > + dontwarn="$dontwarn -Wstack-protector" > + > + # Get all possible GCC warnings > + gl_MANYWARN_ALL_GCC([maybewarn]) > + > + # Remove the ones we don't want, blacklisted earlier > + gl_MANYWARN_COMPLEMENT([wantwarn], [$maybewarn], [$dontwarn]) > + > + # Check for $CC support of each warning > + for w in $wantwarn; do > + gl_WARN_ADD([$w]) > + done Yep, gnulib's macros are nice for this!