In the sprit of https://bugs.freedesktop.org/show_bug.cgi?id=28093.
Short version: use DEFAULT_CFLAGS to store detected cflags, not CFLAGS. Add -Wno-sign-compare and -Wno-strict-prototypes to vala code. Long version: Previously, CFLAGS was used to store default compile options. Automake manual goes on at length why this should be done differently http://www.gnu.org/software/hello/manual/automake/Flag-Variables-Ordering.html. In our case one thing matters: the order of AM_CFLAGS, systemd_CFLAGS and bare CFLAGS. CFLAGS is always applied by automake last, which means that it's not possible to pass e.g. -Wno-sign-compare as a compilation flag for vala generated code in systemd_CFLAGS, because it would be overridden by CFLAGS anyway. Following the automake manual, let's add a new variable DEFAULT_CFLAGS, which is used to store supported flags. They are detected by autoconf. This variable is then AC_SUBSTed and used to initialize AM_CFLAGS in Makefiles. Since we test for gcc support for various -Woption flags, I think we should also test for the -Wno-option flags, so I reused the detection mechanism for the -Wno-option flags used for vala (in NOWARNING_CFLAGS). The goal is to remove spurious compile warnings from vala code. Now -Wno-sign-compare and -Wno-strict-prototypes can be added (despite -Wsign-compare being present in CFLAGS). This kills of the following warnings on my system: In file included from /usr/include/gtk-2.0/gtk/gtk.h:233, from src/systemadm.c:7: /usr/include/gtk-2.0/gtk/gtkitemfactory.h:47: warning: function declaration isn’t a prototype [-Wstrict-prototypes] glib-2.0.vapi: In function ‘g_time_local’: glib-2.0.vapi:2190: warning: declaration of ‘time’ shadows a global declaration [-Wshadow] /usr/include/time.h:186: warning: shadowed declaration is here [-Wshadow] glib-2.0.vapi: In function ‘g_time_format’: glib-2.0.vapi:2202: warning: format not a string literal, format string not checked [-Wformat-nonliteral] src/systemd-interfaces.c: In function ‘_dbus_properties_get’: src/systemd-interfaces.c:14760: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] src/systemd-interfaces.c: In function ‘_dbus_properties_properties_changed’: src/systemd-interfaces.c:14881: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] After this change the generated binary is identical, so hopefully nothing is broken :). --- Makefile.am | 7 +++---- configure.ac | 13 ++++++++++++- m4/attributes.m4 | 20 ++++++++++---------- 3 files changed, 25 insertions(+), 15 deletions(-) diff --git a/Makefile.am b/Makefile.am index 944b871..8903ba7 100644 --- a/Makefile.am +++ b/Makefile.am @@ -17,6 +17,8 @@ ACLOCAL_AMFLAGS = -I m4 +AM_CFLAGS = $(DEFAULT_CFLAGS) + # Dirs of external packages dbuspolicyd...@dbuspolicydir@ dbussessionserviced...@dbussessionservicedir@ @@ -667,10 +669,7 @@ systemadm_CFLAGS = \ $(AM_CFLAGS) \ $(DBUSGLIB_CFLAGS) \ $(GTK_CFLAGS) \ - -Wno-unused-variable \ - -Wno-unused-function \ - -Wno-shadow \ - -Wno-format-nonliteral + $(NOWARNING_CFLAGS) systemadm_VALAFLAGS = \ --pkg=dbus-glib-1 \ diff --git a/configure.ac b/configure.ac index ba9bbf8..9a4a5de 100644 --- a/configure.ac +++ b/configure.ac @@ -47,7 +47,7 @@ AM_PROG_CC_C_O AC_PROG_GCC_TRADITIONAL AC_USE_SYSTEM_EXTENSIONS -CC_CHECK_CFLAGS_APPEND([ \ +CC_CHECK_CFLAGS_APPEND([DEFAULT_CFLAGS], [ \ -pipe \ -Wall \ -W \ @@ -86,6 +86,17 @@ CC_CHECK_CFLAGS_APPEND([ \ -fno-common \ -fdiagnostics-show-option \ -fno-strict-aliasing]) +AC_SUBST(DEFAULT_CFLAGS) + +CC_CHECK_CFLAGS_APPEND([NOWARNING_CFLAGS], [ \ + -Wno-unused-variable \ + -Wno-unused-function \ + -Wno-shadow \ + -Wno-format-nonliteral \ + -Wno-sign-compare \ + -Wno-strict-prototypes ]) +AC_SUBST(NOWARNING_CFLAGS) + LT_PREREQ(2.2) LT_INIT diff --git a/m4/attributes.m4 b/m4/attributes.m4 index 3bf96a3..21171ca 100644 --- a/m4/attributes.m4 +++ b/m4/attributes.m4 @@ -62,22 +62,22 @@ AC_DEFUN([CC_CHECK_CFLAGS], [ [$2], [$3]) ]) -dnl CC_CHECK_CFLAG_APPEND(FLAG, [action-if-found], [action-if-not-found]) -dnl Check for CFLAG and appends them to CFLAGS if supported +dnl CC_CHECK_CFLAG_APPEND(VAR, FLAG, [action-if-found], [action-if-not-found]) +dnl Check for CFLAG and appends them to VAR if supported AC_DEFUN([CC_CHECK_CFLAG_APPEND], [ - AC_CACHE_CHECK([if $CC supports $1 flag], - AS_TR_SH([cc_cv_cflags_$1]), - CC_CHECK_CFLAGS_SILENT([$1]) dnl Don't execute actions here! + AC_CACHE_CHECK([if $CC supports $2 flag], + AS_TR_SH([cc_cv_cflags_$2]), + CC_CHECK_CFLAGS_SILENT([$2]) dnl Don't execute actions here! ) - AS_IF([eval test x$]AS_TR_SH([cc_cv_cflags_$1])[ = xyes], - [CFLAGS="$CFLAGS $1"; DEBUG_CFLAGS="$DEBUG_CFLAGS $1"; $2], [$3]) + AS_IF([eval test x$]AS_TR_SH([cc_cv_cflags_$2])[ = xyes], + [AS_VAR_APPEND([$1], [" $2"]); $3], [$4]) ]) -dnl CC_CHECK_CFLAGS_APPEND([FLAG1 FLAG2], [action-if-found], [action-if-not]) +dnl CC_CHECK_CFLAGS_APPEND([VAR], [FLAG1 FLAG2], [action-if-found], [action-if-not]) AC_DEFUN([CC_CHECK_CFLAGS_APPEND], [ - for flag in $1; do - CC_CHECK_CFLAG_APPEND($flag, [$2], [$3]) + for flag in $2; do + CC_CHECK_CFLAG_APPEND($1, $flag, [$3], [$4]) done ]) -- 1.7.1 _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
