On Tue, Nov 04, 2014 at 03:40:37PM +0100, Michal Privoznik wrote: > The macros under the m4 directory are outdated a bit. When trying > to compile with newer gcc I see some errors:
ACK. The update to m4/warnings.m4 is not really needed, but it does
not hurt :)
>
> make[2]: Entering directory
> '/home/zippy/work/libvirt/libvirt-glib.git/libvirt-glib'
> CC libvirt_glib_1_0_la-libvirt-glib-error.lo
> gcc: warning: switch '-Wmudflap' is no longer supported
>
> Signed-off-by: Michal Privoznik <mpriv...@redhat.com>
> ---
> m4/manywarnings.m4 | 217
> ++++++++++++++++++++++++++++----------------
> m4/virt-compile-warnings.m4 | 214 ++++++++++++++++++++++++++++++++-----------
> m4/warnings.m4 | 2 +-
> 3 files changed, 299 insertions(+), 134 deletions(-)
>
> diff --git a/m4/manywarnings.m4 b/m4/manywarnings.m4
> index fd0e372..3e6dd21 100644
> --- a/m4/manywarnings.m4
> +++ b/m4/manywarnings.m4
> @@ -1,5 +1,5 @@
> -# manywarnings.m4 serial 3
> -dnl Copyright (C) 2008-2012 Free Software Foundation, Inc.
> +# manywarnings.m4 serial 7
> +dnl Copyright (C) 2008-2014 Free Software Foundation, Inc.
> dnl This file is free software; the Free Software Foundation
> dnl gives unlimited permission to copy and/or distribute it,
> dnl with or without modifications, as long as this notice is preserved.
> @@ -35,14 +35,12 @@ AC_DEFUN([gl_MANYWARN_COMPLEMENT],
> # make sure your gcc understands it.
> AC_DEFUN([gl_MANYWARN_ALL_GCC],
> [
> - dnl First, check if -Wno-missing-field-initializers is needed.
> - dnl -Wmissing-field-initializers is implied by -W, but that issues
> - dnl warnings with GCC version before 4.7, for the common idiom
> - dnl of initializing types on the stack to zero, using { 0, }
> + dnl First, check for some issues that only occur when combining multiple
> + dnl gcc warning categories.
> AC_REQUIRE([AC_PROG_CC])
> if test -n "$GCC"; then
>
> - dnl First, check -W -Werror -Wno-missing-field-initializers is supported
> + dnl Check if -W -Werror -Wno-missing-field-initializers is supported
> dnl with the current $CC $CFLAGS $CPPFLAGS.
> AC_MSG_CHECKING([whether -Wno-missing-field-initializers is supported])
> AC_CACHE_VAL([gl_cv_cc_nomfi_supported], [
> @@ -77,108 +75,171 @@ AC_DEFUN([gl_MANYWARN_ALL_GCC],
> ])
> AC_MSG_RESULT([$gl_cv_cc_nomfi_needed])
> fi
> +
> + dnl Next, check if -Werror -Wuninitialized is useful with the
> + dnl user's choice of $CFLAGS; some versions of gcc warn that it
> + dnl has no effect if -O is not also used
> + AC_MSG_CHECKING([whether -Wuninitialized is supported])
> + AC_CACHE_VAL([gl_cv_cc_uninitialized_supported], [
> + gl_save_CFLAGS="$CFLAGS"
> + CFLAGS="$CFLAGS -Werror -Wuninitialized"
> + AC_COMPILE_IFELSE(
> + [AC_LANG_PROGRAM([[]], [[]])],
> + [gl_cv_cc_uninitialized_supported=yes],
> + [gl_cv_cc_uninitialized_supported=no])
> + CFLAGS="$gl_save_CFLAGS"])
> + AC_MSG_RESULT([$gl_cv_cc_uninitialized_supported])
> +
> fi
>
> + # List all gcc warning categories.
> + # To compare this list to your installed GCC's, run this Bash command:
> + #
> + # comm -3 \
> + # <(sed -n 's/^ *\(-[^ ]*\) .*/\1/p' manywarnings.m4 | sort) \
> + # <(gcc --help=warnings | sed -n 's/^ \(-[^ ]*\) .*/\1/p' | sort |
> + # grep -v -x -f <(
> + # awk '/^[^#]/ {print $1}' ../build-aux/gcc-warning.spec))
> +
> gl_manywarn_set=
> for gl_manywarn_item in \
> - -Wall \
> -W \
> - -Wformat-y2k \
> - -Wformat-nonliteral \
> - -Wformat-security \
> - -Winit-self \
> - -Wmissing-include-dirs \
> - -Wswitch-default \
> - -Wswitch-enum \
> - -Wunused \
> - -Wunknown-pragmas \
> - -Wstrict-aliasing \
> - -Wstrict-overflow \
> - -Wsystem-headers \
> - -Wfloat-equal \
> - -Wtraditional \
> - -Wtraditional-conversion \
> - -Wdeclaration-after-statement \
> - -Wundef \
> - -Wshadow \
> - -Wunsafe-loop-optimizations \
> - -Wpointer-arith \
> - -Wbad-function-cast \
> - -Wc++-compat \
> - -Wcast-qual \
> - -Wcast-align \
> - -Wwrite-strings \
> - -Wconversion \
> - -Wsign-conversion \
> - -Wlogical-op \
> - -Waggregate-return \
> - -Wstrict-prototypes \
> - -Wold-style-definition \
> - -Wmissing-prototypes \
> - -Wmissing-declarations \
> - -Wmissing-noreturn \
> - -Wmissing-format-attribute \
> - -Wpacked \
> - -Wpadded \
> - -Wredundant-decls \
> - -Wnested-externs \
> - -Wunreachable-code \
> - -Winline \
> - -Winvalid-pch \
> - -Wlong-long \
> - -Wvla \
> - -Wvolatile-register-var \
> - -Wdisabled-optimization \
> - -Wstack-protector \
> - -Woverlength-strings \
> - -Wbuiltin-macro-redefined \
> - -Wmudflap \
> - -Wpacked-bitfield-compat \
> - -Wsync-nand \
> - ; do
> - gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item"
> - done
> - # The following are not documented in the manual but are included in
> - # output from gcc --help=warnings.
> - for gl_manywarn_item in \
> - -Wattributes \
> - -Wcoverage-mismatch \
> - -Wmultichar \
> - -Wunused-macros \
> - ; do
> - gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item"
> - done
> - # More warnings from gcc 4.6.2 --help=warnings.
> - for gl_manywarn_item in \
> -Wabi \
> + -Waddress \
> + -Waggressive-loop-optimizations \
> + -Wall \
> + -Warray-bounds \
> + -Wattributes \
> + -Wbad-function-cast \
> + -Wbuiltin-macro-redefined \
> + -Wcast-align \
> + -Wchar-subscripts \
> + -Wclobbered \
> + -Wcomment \
> + -Wcomments \
> + -Wcoverage-mismatch \
> -Wcpp \
> + -Wdate-time \
> -Wdeprecated \
> -Wdeprecated-declarations \
> + -Wdisabled-optimization \
> -Wdiv-by-zero \
> -Wdouble-promotion \
> + -Wempty-body \
> -Wendif-labels \
> + -Wenum-compare \
> -Wextra \
> -Wformat-contains-nul \
> -Wformat-extra-args \
> + -Wformat-nonliteral \
> + -Wformat-security \
> + -Wformat-y2k \
> -Wformat-zero-length \
> - -Wformat=2 \
> + -Wfree-nonheap-object \
> + -Wignored-qualifiers \
> + -Wimplicit \
> + -Wimplicit-function-declaration \
> + -Wimplicit-int \
> + -Winit-self \
> + -Winline \
> + -Wint-to-pointer-cast \
> + -Winvalid-memory-model \
> + -Winvalid-pch \
> + -Wjump-misses-init \
> + -Wlogical-op \
> + -Wmain \
> + -Wmaybe-uninitialized \
> + -Wmissing-braces \
> + -Wmissing-declarations \
> + -Wmissing-field-initializers \
> + -Wmissing-include-dirs \
> + -Wmissing-parameter-type \
> + -Wmissing-prototypes \
> -Wmultichar \
> - -Wnormalized=nfc \
> + -Wnarrowing \
> + -Wnested-externs \
> + -Wnonnull \
> + -Wold-style-declaration \
> + -Wold-style-definition \
> + -Wopenmp-simd \
> -Woverflow \
> + -Woverlength-strings \
> + -Woverride-init \
> + -Wpacked \
> + -Wpacked-bitfield-compat \
> + -Wparentheses \
> + -Wpointer-arith \
> + -Wpointer-sign \
> -Wpointer-to-int-cast \
> -Wpragmas \
> + -Wreturn-local-addr \
> + -Wreturn-type \
> + -Wsequence-point \
> + -Wshadow \
> + -Wsizeof-pointer-memaccess \
> + -Wstack-protector \
> + -Wstrict-aliasing \
> + -Wstrict-overflow \
> + -Wstrict-prototypes \
> -Wsuggest-attribute=const \
> + -Wsuggest-attribute=format \
> -Wsuggest-attribute=noreturn \
> -Wsuggest-attribute=pure \
> + -Wswitch \
> + -Wswitch-default \
> + -Wsync-nand \
> + -Wsystem-headers \
> -Wtrampolines \
> + -Wtrigraphs \
> + -Wtype-limits \
> + -Wuninitialized \
> + -Wunknown-pragmas \
> + -Wunsafe-loop-optimizations \
> + -Wunused \
> + -Wunused-but-set-parameter \
> + -Wunused-but-set-variable \
> + -Wunused-function \
> + -Wunused-label \
> + -Wunused-local-typedefs \
> + -Wunused-macros \
> + -Wunused-parameter \
> + -Wunused-result \
> + -Wunused-value \
> + -Wunused-variable \
> + -Wvarargs \
> + -Wvariadic-macros \
> + -Wvector-operation-performance \
> + -Wvla \
> + -Wvolatile-register-var \
> + -Wwrite-strings \
> + \
> ; do
> gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item"
> done
>
> - # Disable the missing-field-initializers warning if needed
> + # gcc --help=warnings outputs an unusual form for this option; list
> + # it here so that the above 'comm' command doesn't report a false match.
> + gl_manywarn_set="$gl_manywarn_set -Wnormalized=nfc"
> +
> + # These are needed for older GCC versions.
> + if test -n "$GCC"; then
> + case `($CC --version) 2>/dev/null` in
> + 'gcc (GCC) '[[0-3]].* | \
> + 'gcc (GCC) '4.[[0-7]].*)
> + gl_manywarn_set="$gl_manywarn_set -fdiagnostics-show-option"
> + gl_manywarn_set="$gl_manywarn_set -funit-at-a-time"
> + ;;
> + esac
> + fi
> +
> + # Disable specific options as needed.
> if test "$gl_cv_cc_nomfi_needed" = yes; then
> gl_manywarn_set="$gl_manywarn_set -Wno-missing-field-initializers"
> fi
>
> + if test "$gl_cv_cc_uninitialized_supported" = no; then
> + gl_manywarn_set="$gl_manywarn_set -Wno-uninitialized"
> + fi
> +
> $1=$gl_manywarn_set
> ])
> diff --git a/m4/virt-compile-warnings.m4 b/m4/virt-compile-warnings.m4
> index b1c4bd7..5081ab6 100644
> --- a/m4/virt-compile-warnings.m4
> +++ b/m4/virt-compile-warnings.m4
> @@ -33,19 +33,96 @@ AC_DEFUN([LIBVIRT_GLIB_COMPILE_WARNINGS],[
> dontwarn="$dontwarn -Wpadded"
> # GCC very confused with -O2
> dontwarn="$dontwarn -Wunreachable-code"
> - # We explicitly need to remove const sometimes
> + # 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="$dontwarn -Wcast-qual"
> - # Allow vars decl in the middle of blocks
> - dontwarn="$dontwarn -Wdeclaration-after-statement"
> - # Using long long is fine
> + # We need to use long long in many places
> dontwarn="$dontwarn -Wlong-long"
> - # Unused macros are ok
> + # We allow manual list of all enum cases without default:
> + dontwarn="$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 the C compiler's -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="$dontwarn -Wmissing-declarations"
> + dontwarn="$dontwarn -Wcast-align"
> + else
> + AC_DEFINE_UNQUOTED([WORKING_PRAGMA_PUSH], 1,
> + [Define to 1 if gcc supports pragma push/pop])
> + 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 the C compiler's -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="$dontwarn -Wpacked"
> dontwarn="$dontwarn -Wunused-macros"
> -
> -
> - # g_clear_object & G_ATOMIC_OP_USE_GCC_BUILTINS causes
> - # violations with this. XXX Fix glib ?
> - dontwarn="$dontwarn -Wbad-function-cast"
> + dontwarn="$dontwarn -Woverlength-strings"
> + dontwarn="$dontwarn -Wstack-protector"
>
> # Get all possible GCC warnings
> gl_MANYWARN_ALL_GCC([maybewarn])
> @@ -53,78 +130,105 @@ AC_DEFUN([LIBVIRT_GLIB_COMPILE_WARNINGS],[
> # Remove the ones we don't want, blacklisted earlier
> gl_MANYWARN_COMPLEMENT([wantwarn], [$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])
> -
> - # Due to gutils.h bug in g_bit_storage
> - gl_WARN_ADD([-Wno-sign-conversion])
> - gl_WARN_ADD([-Wno-conversion])
> - gl_WARN_ADD([-Wno-unused-parameter])
> - # We can't enable this due to horrible spice_usb_device_get_description
> - # signature
> - gl_WARN_ADD([-Wno-format-nonliteral])
> -
> -
> + wantwarn="$wantwarn -Wno-sign-compare"
>
> # GNULIB expects this to be part of -Wc++-compat, but we turn
> # that one off, so we need to manually enable this again
> - gl_WARN_ADD([-Wjump-misses-init])
> + wantwarn="$wantwarn -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).
> + wantwarn="$wantwarn -Wno-format-nonliteral"
> + if test $lv_cv_gcc_wformat_null_works = no; then
> + wantwarn="$wantwarn -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])
> -
> - # Use improved glibc headers
> - 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
> - ])
> + wantwarn="$wantwarn -Wframe-larger-than=4096"
> + dnl wantwarn="$wantwarn -Wframe-larger-than=256"
>
> # Extra special flags
> dnl -fstack-protector stuff passes gl_WARN_ADD with gcc
> dnl on Mingw32, but fails when actually used
> case $host in
> + aarch64-*-*)
> + dnl "error: -fstack-protector not supported for this target [-Werror]"
> + ;;
> *-*-linux*)
> - dnl Fedora only uses -fstack-protector, but doesn't seem to
> - dnl be great overhead in adding -fstack-protector-all instead
> - dnl gl_WARN_ADD([-fstack-protector])
> - gl_WARN_ADD([-fstack-protector-all])
> - gl_WARN_ADD([--param=ssp-buffer-size=4])
> + dnl Prefer -fstack-protector-strong if it's available.
> + dnl There doesn't seem to be great overhead in adding
> + dnl -fstack-protector-all instead of -fstack-protector.
> + dnl
> + dnl We also don't need ssp-buffer-size with -all or -strong,
> + dnl since functions are protected regardless of buffer size.
> + dnl wantwarn="$wantwarn --param=ssp-buffer-size=4"
> + wantwarn="$wantwarn -fstack-protector-strong"
> + ;;
> + *-*-freebsd*)
> + dnl FreeBSD ships old gcc 4.2.1 which doesn't handle
> + dnl -fstack-protector-all well
> + wantwarn="$wantwarn -fstack-protector"
> +
> + wantwarn="$wantwarn -Wno-unused-command-line-argument"
> ;;
> esac
> - gl_WARN_ADD([-fexceptions])
> - gl_WARN_ADD([-fasynchronous-unwind-tables])
> - gl_WARN_ADD([-fdiagnostics-show-option])
> - gl_WARN_ADD([-funit-at-a-time])
> + wantwarn="$wantwarn -fexceptions"
> + wantwarn="$wantwarn -fasynchronous-unwind-tables"
>
> # Need -fipa-pure-const in order to make -Wsuggest-attribute=pure
> # fire even without -O.
> - gl_WARN_ADD([-fipa-pure-const])
> -
> + wantwarn="$wantwarn -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])
> -
> + wantwarn="$wantwarn -Wno-suggest-attribute=pure"
> + wantwarn="$wantwarn -Wno-suggest-attribute=const"
>
> if test "$set_werror" = "yes"
> then
> - gl_WARN_ADD([-Werror])
> + wantwarn="$wantwarn -Werror"
> fi
>
> - WARN_LDFLAGS=$WARN_CFLAGS
> - AC_SUBST([WARN_CFLAGS])
> - AC_SUBST([WARN_LDFLAGS])
> + # Check for $CC support of each warning
> + for w in $wantwarn; do
> + gl_WARN_ADD([$w])
> + done
> +
> + case $host in
> + *-*-linux*)
> + dnl Fall back to -fstack-protector-all if -strong is not available
> + case $WARN_CFLAGS in
> + *-fstack-protector-strong*)
> + ;;
> + *)
> + gl_WARN_ADD(["-fstack-protector-all"])
> + ;;
> + esac
> + ;;
> + esac
> +
> + # Silence certain warnings in gnulib, and use improved glibc headers
> + AC_DEFINE([lint], [1],
> + [Define to 1 if the compiler is checking for lint.])
> + AH_VERBATIM([FORTIFY_SOURCE],
> + [/* Enable compile-time and run-time bounds-checking, and some warnings,
> + without upsetting newer glibc. */
> + #if !defined _FORTIFY_SOURCE && defined __OPTIMIZE__ && __OPTIMIZE__
> + # define _FORTIFY_SOURCE 2
> + #endif
> + ])
> +
> + if test "$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
> ])
> diff --git a/m4/warnings.m4 b/m4/warnings.m4
> index e3d239b..43156f4 100644
> --- a/m4/warnings.m4
> +++ b/m4/warnings.m4
> @@ -1,5 +1,5 @@
> # warnings.m4 serial 11
> -dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
> +dnl Copyright (C) 2008-2014 Free Software Foundation, Inc.
> dnl This file is free software; the Free Software Foundation
> dnl gives unlimited permission to copy and/or distribute it,
> dnl with or without modifications, as long as this notice is preserved.
> --
> 2.0.4
>
> --
> libvir-list mailing list
> libvir-list@redhat.com
> https://www.redhat.com/mailman/listinfo/libvir-list
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