| From c0f075bdee5edabf8f19b68e0880fbd249a89653 Mon Sep 17 00:00:00 2001 |
| From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
| Date: Sat, 3 Jan 2015 15:09:59 +0100 |
| Subject: [PATCH] Add test for -Wunused-but-set-variable |
| |
| The -Wunused-but-set-variable option does not exist in some old gcc |
| versions (gcc 4.5.x), so using it unconditionally breaks the build |
| with such compilers. |
| |
| This commit introduces the AX_CHECK_COMPILE_FLAG m4 macro taken from |
| the autoconf-archive |
| (http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_check_compile_flag.m4), |
| and uses it to detect if the -Wunused-but-set-variable option is |
| supported, and only uses it in this case. |
| |
| Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
| (rebased against v0.1.0) |
| Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de> |
| --- |
| Makefile.am | 2 +- |
| configure.ac | 3 ++ |
| m4/ax_check_compile_flag.m4 | 74 +++++++++++++++++++++++++++++++++++++++++++++ |
| 3 files changed, 78 insertions(+), 1 deletion(-) |
| create mode 100644 m4/ax_check_compile_flag.m4 |
| |
| diff --git a/Makefile.am b/Makefile.am |
| index 5d23e0b..0f51f6a 100644 |
| --- a/Makefile.am |
| +++ b/Makefile.am |
| @@ -6,7 +6,7 @@ AM_CFLAGS = \ |
| -Wnested-externs -Wstrict-prototypes -Wunsafe-loop-optimizations \ |
| -Wwrite-strings -Wno-missing-field-initializers -Wno-unused-parameter \ |
| -Wcast-align -Wformat-nonliteral -Wformat-security -Wswitch-default \ |
| - -Wmissing-include-dirs -Wno-aggregate-return -Wunused-but-set-variable \ |
| + -Wmissing-include-dirs -Wno-aggregate-return @GCC_WARN_UNUSED_BUT_SET@ \ |
| -Warray-bounds -Wold-style-definition -Wsign-compare -Wlarger-than=65537 |
| AM_CFLAGS += -Wno-undef # sophiasip is not -Wundef--safe |
| AM_CFLAGS += -Wno-redundant-decls # sophiasip also contains redundant declarations |
| diff --git a/configure.ac b/configure.ac |
| index 17870a7..f9bb1e4 100644 |
| --- a/configure.ac |
| +++ b/configure.ac |
| @@ -7,6 +7,9 @@ AM_SILENT_RULES([yes]) |
| AC_GNU_SOURCE |
| |
| AC_PROG_CC |
| +AX_CHECK_COMPILE_FLAG([-Wunused-but-set-variable], |
| + [GCC_WARN_UNUSED_BUT_SET=-Wunused-but-set-variable]) |
| +AC_SUBST(GCC_WARN_UNUSED_BUT_SET) |
| |
| LT_PREREQ([2.2]) |
| LT_INIT |
| diff --git a/m4/ax_check_compile_flag.m4 b/m4/ax_check_compile_flag.m4 |
| new file mode 100644 |
| index 0000000..51df0c0 |
| --- /dev/null |
| +++ b/m4/ax_check_compile_flag.m4 |
| @@ -0,0 +1,74 @@ |
| +# =========================================================================== |
| +# http://www.gnu.org/software/autoconf-archive/ax_check_compile_flag.html |
| +# =========================================================================== |
| +# |
| +# SYNOPSIS |
| +# |
| +# AX_CHECK_COMPILE_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT]) |
| +# |
| +# DESCRIPTION |
| +# |
| +# Check whether the given FLAG works with the current language's compiler |
| +# or gives an error. (Warnings, however, are ignored) |
| +# |
| +# ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on |
| +# success/failure. |
| +# |
| +# If EXTRA-FLAGS is defined, it is added to the current language's default |
| +# flags (e.g. CFLAGS) when the check is done. The check is thus made with |
| +# the flags: "CFLAGS EXTRA-FLAGS FLAG". This can for example be used to |
| +# force the compiler to issue an error when a bad flag is given. |
| +# |
| +# INPUT gives an alternative input source to AC_COMPILE_IFELSE. |
| +# |
| +# NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this |
| +# macro in sync with AX_CHECK_{PREPROC,LINK}_FLAG. |
| +# |
| +# LICENSE |
| +# |
| +# Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de> |
| +# Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com> |
| +# |
| +# This program is free software: you can redistribute it and/or modify it |
| +# under the terms of the GNU General Public License as published by the |
| +# Free Software Foundation, either version 3 of the License, or (at your |
| +# option) any later version. |
| +# |
| +# This program is distributed in the hope that it will be useful, but |
| +# WITHOUT ANY WARRANTY; without even the implied warranty of |
| +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General |
| +# Public License for more details. |
| +# |
| +# You should have received a copy of the GNU General Public License along |
| +# with this program. If not, see <http://www.gnu.org/licenses/>. |
| +# |
| +# As a special exception, the respective Autoconf Macro's copyright owner |
| +# gives unlimited permission to copy, distribute and modify the configure |
| +# scripts that are the output of Autoconf when processing the Macro. You |
| +# need not follow the terms of the GNU General Public License when using |
| +# or distributing such scripts, even though portions of the text of the |
| +# Macro appear in them. The GNU General Public License (GPL) does govern |
| +# all other use of the material that constitutes the Autoconf Macro. |
| +# |
| +# This special exception to the GPL applies to versions of the Autoconf |
| +# Macro released by the Autoconf Archive. When you make and distribute a |
| +# modified version of the Autoconf Macro, you may extend this special |
| +# exception to the GPL to apply to your modified version as well. |
| + |
| +#serial 3 |
| + |
| +AC_DEFUN([AX_CHECK_COMPILE_FLAG], |
| +[AC_PREREQ(2.59)dnl for _AC_LANG_PREFIX |
| +AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]flags_$4_$1])dnl |
| +AC_CACHE_CHECK([whether _AC_LANG compiler accepts $1], CACHEVAR, [ |
| + ax_check_save_flags=$[]_AC_LANG_PREFIX[]FLAGS |
| + _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $4 $1" |
| + AC_COMPILE_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])], |
| + [AS_VAR_SET(CACHEVAR,[yes])], |
| + [AS_VAR_SET(CACHEVAR,[no])]) |
| + _AC_LANG_PREFIX[]FLAGS=$ax_check_save_flags]) |
| +AS_IF([test x"AS_VAR_GET(CACHEVAR)" = xyes], |
| + [m4_default([$2], :)], |
| + [m4_default([$3], :)]) |
| +AS_VAR_POPDEF([CACHEVAR])dnl |
| +])dnl AX_CHECK_COMPILE_FLAGS |
| -- |
| 2.1.0 |
| |
