[pulseaudio-discuss] [PATCH] build: make ARM NEON check in configure.ac more strict

[Tanu Kaskinen]

On Thursday, March 28, 2013 03:46:48 PM Peter Meerwald wrote:
> From: Peter Meerwald <p.meerwald at bct-electronic.com>
> 
> the check for NEON so far only checked if -mfpu=neon is understood by the
> compiler, however, this is not enough:
> 
> (i) #include <arm_neon.h> should be checked
> (ii) -mfpu=neon must be passed before CFLAGS because eventually the
> per-library CFLAGS for NEON code in src/Makefile.am are passed to the
> compiler before the global CFLAGS
> 
> in case the build environment passes CFLAGS to configure and we try to set
> conflicting CFLAGS option, the former take precedence; CFLAGS cannot be
> overridden
> 
> this does not fix
> http://lists.freedesktop.org/archives/pulseaudio-discuss/2012-December/0155
> 70.html but at least makes the build fail in configure (and not while
> compiling stuff) and gives better diagnostics
> 
> Signed-off-by: Peter Meerwald <p.meerwald at bct-electronic.com>
> ---
>  configure.ac |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index 8a02cb7..6857890 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -322,9 +322,9 @@ AC_ARG_ENABLE([neon-opt],
>      AS_HELP_STRING([--enable-neon-opt], [Enable NEON optimisations on ARM
> CPUs that support it]))
> 
>  AS_IF([test "x$enable_neon_opt" != "xno"],
> -    [save_CFLAGS="$CFLAGS"; CFLAGS="$CFLAGS -mfpu=neon"
> +    [save_CFLAGS="$CFLAGS"; CFLAGS="-mfpu=neon $CFLAGS"
>       AC_COMPILE_IFELSE(
> -        AC_LANG_PROGRAM([], []),
> +        AC_LANG_PROGRAM([[#include <arm_neon.h>]], []),
>          [
>           HAVE_NEON=1
>           NEON_CFLAGS="-mfpu=neon"
> @@ -338,7 +338,7 @@ AS_IF([test "x$enable_neon_opt" != "xno"],
>      [HAVE_NEON=0])
> 
>  AS_IF([test "x$enable_neon_opt" = "xyes" && test "x$HAVE_NEON" = "x0"],
> -      [AC_MSG_ERROR([*** Compiler does not support -mfpu=neon])])
> +      [AC_MSG_ERROR([*** Compiler does not support -mfpu=neon or CFLAGS
> override -mfpu])])
> 
>  AC_SUBST(HAVE_NEON)
>  AC_SUBST(NEON_CFLAGS)

Applied to the next branch, thanks!

-- 
Tanu