On 12-01-12 11:49 AM, Jon TURNEY wrote:
> Since checking all those warning flags takes an amount of time I find
> irritating,
> here is an attempt at caching the results of checking compiler warning flag
> support
>
> A couple of aspects which need definitely need review or testing:
>
> * I've tried to get things right when not the first flag in the list of
> alternates is
> supported, but this really needs testing with a compiler other than gcc
I used an unrecognised flag such as "-i" and moved it around in the list.
>
> * The cache variable naming policy is a bit opaque me, so the names used may
> need corecting
>
> * I've tried to be careful, but who knows what portability sins I have
> committed :-)
I did not see anything suspicious, everything is autoconf blessed.
>
> This change reduces the time to run the ./configure script produced from a
> configure.ac
> containing just
>
> AC_INIT([test], 1.0)
> XORG_COMPILER_FLAGS
> XORG_CWARNFLAGS
> XORG_STRICT_OPTION
> AC_OUTPUT()
>
> from ~60s to ~20s on my cygwin machine, and from ~15s to ~9s on a linux VM
> running on the
> same hardware
>
> Signed-off-by: Jon TURNEY <[email protected]>
> ---
> xorg-macros.m4.in | 36 +++++++++++++++++++++++-------------
> 1 files changed, 23 insertions(+), 13 deletions(-)
>
> diff --git a/xorg-macros.m4.in b/xorg-macros.m4.in
> index 8197eb6..e6582cb 100644
> --- a/xorg-macros.m4.in
> +++ b/xorg-macros.m4.in
> @@ -1450,6 +1450,7 @@ AC_CHECK_DECL([__SUNPRO_C], [SUNCC="yes"], [SUNCC="no"])
> #
> AC_DEFUN([XORG_TESTSET_CFLAG], [
> AC_REQUIRE([AC_PROG_CC_C99])
> +AC_REQUIRE([AC_PROG_SED])
This is not required, AC_PROG_SED is invoked by XORG_MANPAGE_SECTIONS
which is invoked by XORG_DEFAULT_OPTIONS. There is an assumption that
all modules invoke XORG_DEFAULT_OPTIONS which is the case today. When
new macros are added., there is no attempt to test them outside this
context. No harm done to leave it in, however.
> m4_if([$#], 0, [m4_fatal([XORG_TESTSET_CFLAG was given with an unsupported
> number of arguments])])
> m4_if([$#], 1, [m4_fatal([XORG_TESTSET_CFLAG was given with an unsupported
> number of arguments])])
>
> @@ -1457,11 +1458,12 @@ xorg_testset_save_CFLAGS="$CFLAGS"
>
> if test "x$xorg_testset_unknown_warning_option" = "x" ; then
> CFLAGS="$CFLAGS -Werror=unknown-warning-option"
> - AC_MSG_CHECKING([if $CC supports -Werror=unknown-warning-option])
> - AC_COMPILE_IFELSE([AC_LANG_SOURCE([int i;])],
> - [xorg_testset_unknown_warning_option=yes],
> - [xorg_testset_unknown_warning_option=no])
> - AC_MSG_RESULT([$xorg_testset_unknown_warning_option])
> + AC_CACHE_CHECK([if $CC supports -Werror=unknown-warning-option],
> + xorg_cv_cc_flag_unknown_warning_option,
> + AC_COMPILE_IFELSE([AC_LANG_SOURCE([int i;])],
> +
> [xorg_cv_cc_flag_unknown_warning_option=yes],
> +
> [xorg_cv_cc_flag_unknown_warning_option=no]))
> +
> xorg_testset_unknown_warning_option=$xorg_cv_cc_flag_unknown_warning_option
> CFLAGS="$xorg_testset_save_CFLAGS"
> fi
>
> @@ -1470,11 +1472,12 @@ if test "x$xorg_testset_unused_command_line_argument"
> = "x" ; then
> CFLAGS="$CFLAGS -Werror=unknown-warning-option"
> fi
> CFLAGS="$CFLAGS -Werror=unused-command-line-argument"
> - AC_MSG_CHECKING([if $CC supports -Werror=unused-command-line-argument])
> - AC_COMPILE_IFELSE([AC_LANG_SOURCE([int i;])],
> - [xorg_testset_unused_command_line_argument=yes],
> - [xorg_testset_unused_command_line_argument=no])
> - AC_MSG_RESULT([$xorg_testset_unused_command_line_argument])
> + AC_CACHE_CHECK([if $CC supports -Werror=unused-command-line-argument],
> + xorg_cv_cc_flag_unused_command_line_argument,
> + AC_COMPILE_IFELSE([AC_LANG_SOURCE([int i;])],
> +
> [xorg_cv_cc_flag_unused_command_line_argument=yes],
> +
> [xorg_cv_cc_flag_unused_command_line_argument=no]))
> +
> xorg_testset_unused_command_line_argument=$xorg_cv_cc_flag_unused_command_line_argument
> CFLAGS="$xorg_testset_save_CFLAGS"
> fi
>
> @@ -1491,12 +1494,19 @@ m4_foreach([flag], m4_cdr($@), [
>
> CFLAGS="$CFLAGS ]flag["
>
> +dnl Some hackery here since AC_CACHE_VAL can't handle a non-literal varname
> and
> +dnl flag may contains spaces as it may contain multiple flags, but a cacheid
> can't
> AC_MSG_CHECKING([if $CC supports ]flag[])
> - AC_LINK_IFELSE([AC_LANG_PROGRAM([int i;])],
> - [supported=yes], [supported=no])
> - AC_MSG_RESULT([$supported])
> + cacheid=`AS_ECHO_N([xorg_cv_cc_flag_]flag[]) | $SED 's/ /_/'`
Can you have a look at:
http://www.gnu.org/software/autoconf/manual/autoconf.html#index-AS_005fTR_005fSH-1519
# This outputs "Have it!".
header="sys/some file.h"
eval AS_TR_SH([HAVE_$header])=yes
if test "x$HAVE_sys_some_file_h" = xyes; then echo "Have it!"; fi
This example seem to indicate you would not need to replace spaces with
underscore yourself.
> + AC_CACHE_VAL(AS_TR_SH($cacheid),
> + [AC_LINK_IFELSE([AC_LANG_PROGRAM([int i;])],
> + [eval AS_TR_SH($cacheid)=yes],
> + [eval AS_TR_SH($cacheid)=no])])
> +
> CFLAGS="$xorg_testset_save_CFLAGS"
>
> + eval supported=$AS_TR_SH($cacheid)
> + AC_MSG_RESULT([$supported])
> if test "$supported" = "yes" ; then
> $1="$$1 ]flag["
> found="yes"
I have one question regarding how you use the cache file. You are aware
that some of the Automake variables we create in the various xorg
modules do not have a unique name across packages. For example. in the
driver section, PKG_CHECK MODULES(XORG, ...) is very common. The
variable pkg_cv_XORG_LIBS does not have the same value for all drivers.
Using a cache file will almost always return the wrong value. How do you
work around this issue?
For compiler and OS related variables, it is safe to use a cache file as
these values are the same for all modules. Only a software
install/uninstall might make the cache invalid. The patch you propose is
still fine as the warnings will not change unless you change the compiler.
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