[pulseaudio-discuss] [ANNOUNCE] PulseAudio 2.99.3 (3.0 RC3)

[Peter Meerwald]

Hello,

> I've been trying to get this to build on Fedora 18 on ARM to test the
> UCM support and I'm running into an issue with what appears to be the
> build ignoring the distro CFLAGS. Basically we don't currently build
> for NEON as it's not guaranteed to be available on all platforms but
> rather then rely on optimised code paths and run time detection for
> NEON use.

> I'm running into the following error where it's making an assumption
> that NEON is there so trying to use it but as we're not using it the
> build is failing.

> libtool: compile:  armv7hl-redhat-linux-gnueabi-gcc -std=gnu99
> -DHAVE_CONFIG_H -I. -I.. -DFASTPATH -I../src -I../src/modules
> -I../src/modules -pthread
> -DPA_ALSA_PATHS_DIR=\"/usr/share/pulseaudio/alsa-mixer/paths\"
> -DPA_ALSA_PROFILE_SETS_DIR=\"/usr/share/pulseaudio/alsa-mixer/profile-sets\"
> -mfpu=neon -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
> -fstack-protector --param=ssp-buffer-size=4 -march=armv7-a
> -mfpu=vfpv3-d16 -mfloat-abi=hard -W -Wextra -Wno-long-long
> -Wno-overlength-strings -Wunsafe-loop-optimizations -Wundef -Wformat=2
> -Wlogical-op -Wsign-compare -Wformat-security -Wmissing-include-dirs
> -Wformat-nonliteral -Wpointer-arith -Winit-self
> -Wdeclaration-after-statement -Wfloat-equal -Wmissing-prototypes
> -Wredundant-decls -Wmissing-declarations -Wmissing-noreturn -Wshadow
> -Wendif-labels -Wcast-align -Wstrict-aliasing -Wwrite-strings
> -Wno-unused-parameter -ffast-math -fno-common
> -fdiagnostics-show-option -c pulsecore/sconv_neon.c  -fPIC -DPIC -o
> .libs/libpulsecore_sconv_neon_la-sconv_neon.o
> In file included from pulsecore/sconv_neon.c:30:0:
> /usr/lib/gcc/armv7hl-redhat-linux-gnueabi/4.7.2/include/arm_neon.h:32:2:
> error: #error You must enable NEON instructions (e.g.
> -mfloat-abi=softfp -mfpu=neon) to use arm_neon.h

your compiler invokation has -mfpu=neon followed by -mfpu=vfpv3-d16 (the 
later option overrides the previous), hence NEON is not available

I think the PulseAudio's configure.ac (snippet below) is incorrect; it 
merely checks if the -mfpu=neon is understood as a compiler option, but 
not if it actually works (e.g. by #including arm_neon.h)

AS_IF([test "x$enable_neon_opt" != "xno"],
    [save_CFLAGS="$CFLAGS"; CFLAGS="$CFLAGS -mfpu=neon"
     AC_COMPILE_IFELSE(
        AC_LANG_PROGRAM([], []),
        [
         HAVE_NEON=1
         NEON_CFLAGS="-mfpu=neon"
        ],
        [
         HAVE_NEON=0
         NEON_CFLAGS=
        ])
     CFLAGS="$save_CFLAGS"
    ],
    [HAVE_NEON=0])

a second issue is may be in the compiler invokation: -mfpu=neon is the 
one of the first options (coming from NEON_CFLAGS), followed by those 
probably coming from the toolchain/cross-compilation environment

src/Makefile.am has:

if HAVE_NEON
noinst_LTLIBRARIES += libpulsecore_sconv_neon.la
libpulsecore_sconv_neon_la_SOURCES = pulsecore/sconv_neon.c
libpulsecore_sconv_neon_la_CFLAGS = $(AM_CFLAGS) $(NEON_CFLAGS)
libpulsecore_ at PA_MAJORMINOR@_la_LIBADD += libpulsecore_sconv_neon.la
endif

so NEON_CFLAGS (determined by configure) is supposed to override whatever 
your compilation environment provides; however, this does see so work as 
-mfpu=vfpv3-d16 is coming after -mfpu=neon

I'll have a closer look...

regards, p.

-- 

Peter Meerwald
+43-664-2444418 (mobile)