[FFmpeg-devel] [PATCH 1/2] avutil/attributes: extend av_uninit to clang

[Michael Niedermayer]

On Sat, Sep 19, 2015 at 01:00:17AM -0400, Ganesh Ajjanagadde wrote:
> Commit 6dac8c8327 disabled av_uninit for clang, due to some useless warnings.
> The concept of av_uninit is inherently useful though. This patch silences a
> bunch of warnings on clang e.g
> http://fate.ffmpeg.org/log.cgi?time=20150918181527&log=compile&slot=x86_64-darwin-clang-polly-vectorize-stripmine-3.7.
> Furthermore, it should be useful for general usage of av_uninit in future.
> 
> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
> ---
>  libavutil/attributes.h | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/libavutil/attributes.h b/libavutil/attributes.h
> index 50e8eb3..b4b5f13 100644
> --- a/libavutil/attributes.h
> +++ b/libavutil/attributes.h
> @@ -141,6 +141,12 @@
>  
>  #if defined(__GNUC__) && !defined(__INTEL_COMPILER) && !defined(__clang__)
>  #    define av_uninit(x) x=x
> +#elif defined(__clang__)
> +#    define av_uninit(x) \
> +        _Pragma("clang diagnostic push") \
> +        _Pragma("clang diagnostic ignored \"-Wuninitialized\"") \
> +        x=x \
> +        _Pragma("clang diagnostic pop")
>  #else

this fails with clang version 3.1 (trunk 144800)

AR      libavdevice/libavdevice.a
CC      libavfilter/af_aecho.o
In file included from libavfilter/af_aecho.c:1:
libavfilter/af_aecho.c:226:315: error: expected identifier or '('
static void echo_samples_dblp(AudioEchoContext *ctx, uint8_t **delayptrs, uint8_t * const *src, uint8_t **dst, int nb_samples, int channels) { const double out_gain = ctx->out_gain; const double in_gain = ctx->in_gain; const int nb_echoes = ctx->nb_echoes; const int max_samples = ctx->max_samples; int i, j, chan,#pragma clang diagnostic push#pragma clang diagnostic ignored "-Wuninitialized" index=index#pragma clang diagnostic pop; ((void)0); for (chan = 0; chan < channels; chan++) { const double *s = (double *)src[chan]; double *d = (double *)dst[chan]; double *dbuf = (double *)delayptrs[chan]; index = ctx->delay_index; for (i = 0; i < nb_samples; i++, s++, d++) { double out, in; in = *s; out = in * in_gain; for (j = 0; j < nb_echoes; j++) { int ix = index + max_samples - ctx->samples[j]; ix = (((ix) >= (max_samples)) ? (ix) - (max_samples) : (ix)); out += dbuf[ix] * ctx->decay[j]; } out *= out_gain; *d = av_clipd_c(out, -1.0, 1.0); dbuf[index] = in; index = (((index + 1) >= (max_samples)) ? (index + 1) - (max_samples) : (index + 1)); } } ctx->delay_index = index; }
                                                                                                                                                                                                                                                                                                                          ^
...

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When you are offended at any man's fault, turn to yourself and study your
own failings. Then you will forget your anger. -- Epictetus
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