[Mesa-dev] [PATCH 01/19] configure: Add and use AX_CHECK_COMPILE_FLAG

Matt Turner mattst88 at gmail.com
Mon Aug 28 21:57:03 UTC 2017


This makes it a lot clearer what's happening (at least I think so), and
will make future additions much simpler.
---
 configure.ac                | 94 ++++++++++++---------------------------------
 m4/ax_check_compile_flag.m4 | 74 +++++++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+), 69 deletions(-)
 create mode 100644 m4/ax_check_compile_flag.m4

diff --git a/configure.ac b/configure.ac
index 53d52f6d52..84b0805401 100644
--- a/configure.ac
+++ b/configure.ac
@@ -282,81 +282,37 @@ esac
 
 AM_CONDITIONAL(HAVE_ANDROID, test "x$android" = xyes)
 
-dnl Add flags for gcc and g++
-if test "x$GCC" = xyes; then
-    CFLAGS="$CFLAGS -Wall"
+dnl
+dnl Check compiler flags
+dnl
+AX_CHECK_COMPILE_FLAG([-Wall],                                 [CFLAGS="$CFLAGS -Wall"])
+AX_CHECK_COMPILE_FLAG([-Werror=implicit-function-declaration], [CFLAGS="$CFLAGS -Werror=implicit-function-declaration"])
+AX_CHECK_COMPILE_FLAG([-Werror=missing-prototypes],            [CFLAGS="$CFLAGS -Werror=missing-prototypes"])
+AX_CHECK_COMPILE_FLAG([-Wmissing-prototypes],                  [CFLAGS="$CFLAGS -Wmissing-prototypes"])
+AX_CHECK_COMPILE_FLAG([-fno-math-errno],                       [CFLAGS="$CFLAGS -fno-math-errno"])
+AX_CHECK_COMPILE_FLAG([-fno-trapping-math],                    [CFLAGS="$CFLAGS -fno-trapping-math"])
+AX_CHECK_COMPILE_FLAG([-fvisibility=hidden],                   [VISIBILITY_CFLAGS="-fvisibility=hidden"])
+AX_CHECK_COMPILE_FLAG([-Werror=pointer-arith],                 [MSVC2013_COMPAT_CFLAGS="-Werror=pointer-arith"])
+AX_CHECK_COMPILE_FLAG([-Werror=vla],                           [MSVC2013_COMPAT_CFLAGS="-Werror=vla"])
 
+dnl
+dnl Check C++ compiler flags
+dnl
+AC_LANG_PUSH([C++])
+AX_CHECK_COMPILE_FLAG([-Wall],                                 [CXXFLAGS="$CXXFLAGS -Wall"])
+AX_CHECK_COMPILE_FLAG([-fno-math-errno],                       [CXXFLAGS="$CXXFLAGS -fno-math-errno"])
+AX_CHECK_COMPILE_FLAG([-fno-trapping-math],                    [CXXFLAGS="$CXXFLAGS -fno-trapping-math"])
+AX_CHECK_COMPILE_FLAG([-fvisibility=hidden],                   [VISIBILITY_CXXFLAGS="-fvisibility=hidden"])
+AX_CHECK_COMPILE_FLAG([-Werror=pointer-arith],                 [MSVC2013_COMPAT_CXXFLAGS="-Werror=pointer-arith"])
+AX_CHECK_COMPILE_FLAG([-Werror=vla],                           [MSVC2013_COMPAT_CXXFLAGS="-Werror=vla"])
+AC_LANG_POP([C++])
+
+if test "x$GCC" = xyes; then
     if test "x$USE_GNU99" = xyes; then
         CFLAGS="$CFLAGS -std=gnu99"
     else
         CFLAGS="$CFLAGS -std=c99"
     fi
-
-    # Enable -Werror=implicit-function-declaration and
-    # -Werror=missing-prototypes, if available, or otherwise, just
-    # -Wmissing-prototypes.  This is particularly useful to avoid
-    # generating a loadable driver module that has undefined symbols.
-    save_CFLAGS="$CFLAGS"
-    AC_MSG_CHECKING([whether $CC supports -Werror=missing-prototypes])
-    CFLAGS="$CFLAGS -Werror=implicit-function-declaration"
-    CFLAGS="$CFLAGS -Werror=missing-prototypes"
-    AC_LINK_IFELSE([AC_LANG_PROGRAM()],
-                   AC_MSG_RESULT([yes]),
-                   [CFLAGS="$save_CFLAGS -Wmissing-prototypes";
-                    AC_MSG_RESULT([no])])
-
-    # Enable -fvisibility=hidden if using a gcc that supports it
-    save_CFLAGS="$CFLAGS"
-    AC_MSG_CHECKING([whether $CC supports -fvisibility=hidden])
-    VISIBILITY_CFLAGS="-fvisibility=hidden"
-    CFLAGS="$CFLAGS $VISIBILITY_CFLAGS"
-    AC_LINK_IFELSE([AC_LANG_PROGRAM()], AC_MSG_RESULT([yes]),
-                   [VISIBILITY_CFLAGS=""; AC_MSG_RESULT([no])])
-
-    # Restore CFLAGS; VISIBILITY_CFLAGS are added to it where needed.
-    CFLAGS=$save_CFLAGS
-
-    # We don't want floating-point math functions to set errno or trap
-    CFLAGS="$CFLAGS -fno-math-errno -fno-trapping-math"
-
-    # Flags to help ensure that certain portions of the code -- and only those
-    # portions -- can be built with MSVC:
-    # - src/util, src/gallium/auxiliary, rc/gallium/drivers/llvmpipe, and
-    # - non-Linux/Posix OpenGL portions needs to build on MSVC 2013 (which
-    #   supports most of C99)
-    # - the rest has no compiler compiler restrictions
-    MSVC2013_COMPAT_CFLAGS="-Werror=pointer-arith"
-    MSVC2013_COMPAT_CXXFLAGS="-Werror=pointer-arith"
-
-    # Enable -Werror=vla if compiler supports it
-    save_CFLAGS="$CFLAGS"
-    AC_MSG_CHECKING([whether $CC supports -Werror=vla])
-    CFLAGS="$CFLAGS -Werror=vla"
-    AC_LINK_IFELSE([AC_LANG_PROGRAM()],
-                   [MSVC2013_COMPAT_CFLAGS="$MSVC2013_COMPAT_CFLAGS -Werror=vla";
-                    MSVC2013_COMPAT_CXXFLAGS="$MSVC2013_COMPAT_CXXFLAGS -Werror=vla";
-                    AC_MSG_RESULT([yes])],
-                    AC_MSG_RESULT([no]))
-    CFLAGS="$save_CFLAGS"
-fi
-if test "x$GXX" = xyes; then
-    CXXFLAGS="$CXXFLAGS -Wall"
-
-    # Enable -fvisibility=hidden if using a gcc that supports it
-    save_CXXFLAGS="$CXXFLAGS"
-    AC_MSG_CHECKING([whether $CXX supports -fvisibility=hidden])
-    VISIBILITY_CXXFLAGS="-fvisibility=hidden"
-    CXXFLAGS="$CXXFLAGS $VISIBILITY_CXXFLAGS"
-    AC_LANG_PUSH([C++])
-    AC_LINK_IFELSE([AC_LANG_PROGRAM()], AC_MSG_RESULT([yes]),
-                   [VISIBILITY_CXXFLAGS="" ; AC_MSG_RESULT([no])])
-    AC_LANG_POP([C++])
-
-    # Restore CXXFLAGS; VISIBILITY_CXXFLAGS are added to it where needed.
-    CXXFLAGS=$save_CXXFLAGS
-
-    # We don't want floating-point math functions to set errno or trap
-    CXXFLAGS="$CXXFLAGS -fno-math-errno -fno-trapping-math"
 fi
 
 AC_SUBST([MSVC2013_COMPAT_CFLAGS])
diff --git a/m4/ax_check_compile_flag.m4 b/m4/ax_check_compile_flag.m4
new file mode 100644
index 0000000000..dcabb92a14
--- /dev/null
+++ b/m4/ax_check_compile_flag.m4
@@ -0,0 +1,74 @@
+# ===========================================================================
+#  https://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 at gmx.de>
+#   Copyright (c) 2011 Maarten Bosmans <mkbosmans at 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 <https://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 5
+
+AC_DEFUN([AX_CHECK_COMPILE_FLAG],
+[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF
+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_VAR_IF(CACHEVAR,yes,
+  [m4_default([$2], :)],
+  [m4_default([$3], :)])
+AS_VAR_POPDEF([CACHEVAR])dnl
+])dnl AX_CHECK_COMPILE_FLAGS
-- 
2.13.5



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