On Fri, Apr 01, 2011 at 10:02:18AM -0600, Eric Blake wrote:
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...
The new series moves this file
+ # 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.
The problem isn't with the compilation of gnulib - that doesn't use any of these flags. The issue is with various things in the gnulib header files, which impact compilation of the main libvirt code. eg ../gnulib/lib/gettext.h:218:3: error: variable length array 'msg_ctxt_id' is used [-Wvla]
+ 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="$dontwarn -W"
-W is the same as -Wextra - that turns on a lot of useful warnings. Can we fine-tune it to just disable the needed warnings?
Removing that means I need a manual check for -Wno-sign-compare since gl_MANYWAY_COMPLEMENT can't see that -W include -Wsign-compare
+ dontwarn="$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!
Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|