mirror of
https://gitlab.com/libvirt/libvirt.git
synced 2024-10-30 01:43:23 +00:00
6e148567fd
Commit 8b8fcdea introduced a check for broken gcc -Wlogical-op,
but did not guard the check against non-gcc compilers, which might
lead to spurious failures when another compiler encounters an
unknown pragma. Additionally, all of our compiler warning logic
should belong in a single file, and use cache variables to allow
overriding the decision at configure time if necessary.
* configure.ac (BROKEN_GCC_WLOGICALOP): Move...
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): ...here,
and update to modern autoconf idioms.
222 lines
8.2 KiB
Plaintext
222 lines
8.2 KiB
Plaintext
dnl
|
|
dnl Enable all known GCC compiler warnings, except for those
|
|
dnl we can't yet cope with
|
|
dnl
|
|
AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[
|
|
dnl ******************************
|
|
dnl More compiler warnings
|
|
dnl ******************************
|
|
|
|
AC_ARG_ENABLE([werror],
|
|
AS_HELP_STRING([--enable-werror], [Use -Werror (if supported)]),
|
|
[set_werror="$enableval"],
|
|
[if test -d $srcdir/.git; then
|
|
is_git_version=true
|
|
set_werror=yes
|
|
else
|
|
set_werror=no
|
|
fi])
|
|
|
|
# List of warnings that are not relevant / wanted
|
|
|
|
# Don't care about C++ compiler compat
|
|
dontwarn="$dontwarn -Wc++-compat"
|
|
dontwarn="$dontwarn -Wabi"
|
|
dontwarn="$dontwarn -Wdeprecated"
|
|
# Don't care about ancient C standard compat
|
|
dontwarn="$dontwarn -Wtraditional"
|
|
# Don't care about ancient C standard compat
|
|
dontwarn="$dontwarn -Wtraditional-conversion"
|
|
# Ignore warnings in /usr/include
|
|
dontwarn="$dontwarn -Wsystem-headers"
|
|
# Happy for compiler to add struct padding
|
|
dontwarn="$dontwarn -Wpadded"
|
|
# GCC very confused with -O2
|
|
dontwarn="$dontwarn -Wunreachable-code"
|
|
# Too many to deal with
|
|
dontwarn="$dontwarn -Wconversion"
|
|
# Too many to deal with
|
|
dontwarn="$dontwarn -Wsign-conversion"
|
|
# GNULIB gettext.h violates
|
|
dontwarn="$dontwarn -Wvla"
|
|
# Many GNULIB header violations
|
|
dontwarn="$dontwarn -Wundef"
|
|
# Need to allow bad cast for execve()
|
|
dontwarn="$dontwarn -Wcast-qual"
|
|
# We need to use long long in many places
|
|
dontwarn="$dontwarn -Wlong-long"
|
|
# We allow manual list of all enum cases without default:
|
|
dontwarn="$dontwarn -Wswitch-default"
|
|
# We allow optional default: instead of listing all enum values
|
|
dontwarn="$dontwarn -Wswitch-enum"
|
|
# Not a problem since we don't use -fstrict-overflow
|
|
dontwarn="$dontwarn -Wstrict-overflow"
|
|
# Not a problem since we don't use -funsafe-loop-optimizations
|
|
dontwarn="$dontwarn -Wunsafe-loop-optimizations"
|
|
# Things like virAsprintf mean we can't use this
|
|
dontwarn="$dontwarn -Wformat-nonliteral"
|
|
# Gnulib's stat-time.h violates this
|
|
dontwarn="$dontwarn -Waggregate-return"
|
|
# gcc 4.4.6 complains this is C++ only; gcc 4.7.0 implies this from -Wall
|
|
dontwarn="$dontwarn -Wenum-compare"
|
|
|
|
# gcc 4.2 treats attribute(format) as an implicit attribute(nonnull),
|
|
# which triggers spurious warnings for our usage
|
|
AC_CACHE_CHECK([whether gcc -Wformat allows NULL strings],
|
|
[lv_cv_gcc_wformat_null_works], [
|
|
save_CFLAGS=$CFLAGS
|
|
CFLAGS='-Wunknown-pragmas -Werror -Wformat'
|
|
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
|
|
#include <stddef.h>
|
|
static __attribute__ ((__format__ (__printf__, 1, 2))) int
|
|
foo (const char *fmt, ...) { return !fmt; }
|
|
]], [[
|
|
return foo(NULL);
|
|
]])],
|
|
[lv_cv_gcc_wformat_null_works=yes],
|
|
[lv_cv_gcc_wformat_null_works=no])
|
|
CFLAGS=$save_CFLAGS])
|
|
|
|
# Gnulib uses '#pragma GCC diagnostic push' to silence some
|
|
# warnings, but older gcc doesn't support this.
|
|
AC_CACHE_CHECK([whether pragma GCC diagnostic push works],
|
|
[lv_cv_gcc_pragma_push_works], [
|
|
save_CFLAGS=$CFLAGS
|
|
CFLAGS='-Wunknown-pragmas -Werror'
|
|
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
|
|
#pragma GCC diagnostic push
|
|
#pragma GCC diagnostic pop
|
|
]])],
|
|
[lv_cv_gcc_pragma_push_works=yes],
|
|
[lv_cv_gcc_pragma_push_works=no])
|
|
CFLAGS=$save_CFLAGS])
|
|
if test $lv_cv_gcc_pragma_push_works = no; then
|
|
dontwarn="$dontwarn -Wmissing-prototypes"
|
|
dontwarn="$dontwarn -Wmissing-declarations"
|
|
fi
|
|
|
|
dnl Check whether strchr(s, char variable) causes a bogus compile
|
|
dnl warning, which is the case with GCC < 4.6 on some glibc
|
|
AC_CACHE_CHECK([whether GCC -Wlogical-op gives bogus warnings],
|
|
[lv_cv_gcc_wlogical_op_broken], [
|
|
save_CFLAGS="$CFLAGS"
|
|
CFLAGS="-O2 -Wlogical-op -Werror"
|
|
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
|
|
#include <string.h>
|
|
]], [[
|
|
const char *haystack;
|
|
char needle;
|
|
return strchr(haystack, needle) == haystack;]])],
|
|
[lv_cv_gcc_wlogical_op_broken=no],
|
|
[lv_cv_gcc_wlogical_op_broken=yes])
|
|
CFLAGS="$save_CFLAGS"])
|
|
|
|
# We might fundamentally need some of these disabled forever, but
|
|
# ideally we'd turn many of them on
|
|
dontwarn="$dontwarn -Wfloat-equal"
|
|
dontwarn="$dontwarn -Wdeclaration-after-statement"
|
|
dontwarn="$dontwarn -Wcast-qual"
|
|
dontwarn="$dontwarn -Wconversion"
|
|
dontwarn="$dontwarn -Wsign-conversion"
|
|
dontwarn="$dontwarn -Wpacked"
|
|
dontwarn="$dontwarn -Wunused-macros"
|
|
dontwarn="$dontwarn -Woverlength-strings"
|
|
dontwarn="$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
|
|
|
|
# GNULIB uses '-W' (aka -Wextra) which includes a bunch of stuff.
|
|
# Unfortunately, this means you can't simply use '-Wsign-compare'
|
|
# with gl_MANYWARN_COMPLEMENT
|
|
# So we have -W enabled, and then have to explicitly turn off...
|
|
gl_WARN_ADD([-Wno-sign-compare])
|
|
|
|
# GNULIB expects this to be part of -Wc++-compat, but we turn
|
|
# that one off, so we need to manually enable this again
|
|
gl_WARN_ADD([-Wjump-misses-init])
|
|
|
|
# GNULIB turns on -Wformat=2 which implies -Wformat-nonliteral,
|
|
# so we need to manually re-exclude it. Also, older gcc 4.2
|
|
# added an implied ATTRIBUTE_NONNULL on any parameter marked
|
|
# ATTRIBUTE_FMT_PRINT, which causes -Wformat failure on our
|
|
# intentional use of virReportError(code, NULL).
|
|
gl_WARN_ADD([-Wno-format-nonliteral])
|
|
if test $lv_cv_gcc_wformat_null_works = no; then
|
|
gl_WARN_ADD([-Wno-format])
|
|
fi
|
|
|
|
# This should be < 256 really. Currently we're down to 4096,
|
|
# but using 1024 bytes sized buffers (mostly for virStrerror)
|
|
# stops us from going down further
|
|
gl_WARN_ADD([-Wframe-larger-than=4096])
|
|
dnl gl_WARN_ADD([-Wframe-larger-than=256])
|
|
|
|
# Silence certain warnings in gnulib, and use improved glibc headers
|
|
AC_DEFINE([lint], [1],
|
|
[Define to 1 if the compiler is checking for lint.])
|
|
AH_VERBATIM([FORTIFY_SOURCE],
|
|
[/* Enable compile-time and run-time bounds-checking, and some warnings,
|
|
without upsetting newer glibc. */
|
|
#if !defined _FORTIFY_SOURCE && defined __OPTIMIZE__ && __OPTIMIZE__
|
|
# define _FORTIFY_SOURCE 2
|
|
#endif
|
|
])
|
|
|
|
# Extra special flags
|
|
dnl -fstack-protector stuff passes gl_WARN_ADD with gcc
|
|
dnl on Mingw32, but fails when actually used
|
|
case $host in
|
|
*-*-linux*)
|
|
dnl Fedora only uses -fstack-protector, but doesn't seem to
|
|
dnl be great overhead in adding -fstack-protector-all instead
|
|
dnl gl_WARN_ADD([-fstack-protector])
|
|
gl_WARN_ADD([-fstack-protector-all])
|
|
gl_WARN_ADD([--param=ssp-buffer-size=4])
|
|
;;
|
|
esac
|
|
gl_WARN_ADD([-fexceptions])
|
|
gl_WARN_ADD([-fasynchronous-unwind-tables])
|
|
gl_WARN_ADD([-fdiagnostics-show-option])
|
|
gl_WARN_ADD([-funit-at-a-time])
|
|
|
|
# Need -fipa-pure-const in order to make -Wsuggest-attribute=pure
|
|
# fire even without -O.
|
|
gl_WARN_ADD([-fipa-pure-const])
|
|
# We should eventually enable this, but right now there are at
|
|
# least 75 functions triggering warnings.
|
|
gl_WARN_ADD([-Wno-suggest-attribute=pure])
|
|
gl_WARN_ADD([-Wno-suggest-attribute=const])
|
|
|
|
if test "$set_werror" = "yes"
|
|
then
|
|
gl_WARN_ADD([-Werror])
|
|
fi
|
|
|
|
WARN_LDFLAGS=$WARN_CFLAGS
|
|
AC_SUBST([WARN_CFLAGS])
|
|
AC_SUBST([WARN_LDFLAGS])
|
|
|
|
dnl Needed to keep compile quiet on python 2.4
|
|
save_WARN_CFLAGS=$WARN_CFLAGS
|
|
WARN_CFLAGS=
|
|
gl_WARN_ADD([-Wno-redundant-decls])
|
|
WARN_PYTHON_CFLAGS=$WARN_CFLAGS
|
|
AC_SUBST(WARN_PYTHON_CFLAGS)
|
|
WARN_CFLAGS=$save_WARN_CFLAGS
|
|
|
|
if test "$gl_cv_warn_c__Wlogical_op" = yes &&
|
|
test "$lv_cv_gcc_wlogical_op_broken" = yes; then
|
|
AC_DEFINE_UNQUOTED([BROKEN_GCC_WLOGICALOP], 1,
|
|
[Define to 1 if gcc -Wlogical-op reports false positives on strchr])
|
|
fi
|
|
])
|