[FFmpeg-devel] [PATCH] fix few compiler warnings
Michael Niedermayer
michael at niedermayer.cc
Mon May 23 13:59:36 CEST 2016
On Mon, May 23, 2016 at 07:24:23AM -0400, Ronald S. Bultje wrote:
> Hi,
>
> On Sun, May 22, 2016 at 11:39 PM, Michael Niedermayer <
> michael at niedermayer.cc> wrote:
>
> > On Sun, May 22, 2016 at 01:51:05AM +0000, Davinder Singh wrote:
> > > On Sun, May 22, 2016 at 2:09 AM Michael Niedermayer
> > <michael at niedermayer.cc>
> > > wrote:
> > >
> > > > On Sat, May 21, 2016 at 02:21:17PM +0000, Davinder Singh wrote:
> > > > > hi,
> > > > >
> > > > > this patch fixes following compiler warnings:
> > > > >
> > > > > libavcodec/cfhd.c:346:78: warning: format specifies type 'unsigned
> > short'
> > > > > but the argument has type 'int' [-Wformat]
> > > > > av_log(avctx, AV_LOG_DEBUG, "Small chunk length %"PRIu16"
> > > > > %s\n", data * 4, tag < 0 ? "optional" : "required");
> > > > > ~~
> > > > > ^~~~~~~~
> > > > > libavcodec/cfhd.c:472:110: warning: format specifies type 'unsigned
> > > > short'
> > > > > but the argument has type 'int' [-Wformat]
> > > > > av_log(avctx, AV_LOG_DEBUG, "Start of lowpass coeffs
> > > > component
> > > > > %"PRIu16" height:%d, width:%d\n", s->channel_num, lowpass_height,
> > > > > lowpass_width);
> > > > >
> > > > > ~~ ^~~~~~~~~~~~~~
> > > > > libavcodec/cfhd.c:490:77: warning: format specifies type 'unsigned
> > short'
> > > > > but the argument has type 'int' [-Wformat]
> > > > > av_log(avctx, AV_LOG_DEBUG, "Lowpass coefficients
> > > > %"PRIu16"\n",
> > > > > lowpass_width * lowpass_height);
> > > > > ~~
> > > > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > > >
> > > > >
> > > > >
> > > > > libavcodec/dv_tablegen.c:30:60: warning: format specifies type
> > 'char' but
> > > > > the argument has type 'uint32_t' (aka 'unsigned int') [-Wformat]
> > > > > "{0x%"PRIx32", %"PRId8"}", data[i].vlc,
> > data[i].size)
> > > > >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
> > > > > libavcodec/tableprint.h:37:29: note: expanded from macro
> > > > > 'WRITE_1D_FUNC_ARGV'
> > > > > printf(" "fmtstr",", __VA_ARGS__);\
> > > > > ^~~~~~~~~~~
> > > > > libavcodec/dv_tablegen.c:30:60: warning: format specifies type
> > 'char' but
> > > > > the argument has type 'uint32_t' (aka 'unsigned int') [-Wformat]
> > > > > "{0x%"PRIx32", %"PRId8"}", data[i].vlc,
> > data[i].size)
> > > > >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
> > > > >
> > > > >
> > > > >
> > > > > libavfilter/af_hdcd.c:896:57: warning: shifting a negative signed
> > value
> > > > is
> > > > > undefined [-Wshift-negative-value]
> > > > > state->readahead = readaheadtab[bits & ~(-1 << 8)];
> > > > >
> > > > >
> > > > >
> > > > > libavfilter/vf_hwdownload.c:59:5: warning: ignoring return value of
> > > > > function declared with warn_unused_result attribute [-Wunused-result]
> > > > > ff_formats_ref(infmts, &avctx->inputs[0]->out_formats);
> > > > > ^~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > > > libavfilter/vf_hwdownload.c:60:5: warning: ignoring return value of
> > > > > function declared with warn_unused_result attribute [-Wunused-result]
> > > > > ff_formats_ref(outfmts, &avctx->outputs[0]->in_formats);
> > > > > ^~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > > >
> > > > >
> > > > >
> > > > > libavutil/opencl.c:456:17: warning: variable 'kernel_source' is used
> > > > > uninitialized whenever 'for' loop exits because its condition is
> > false
> > > > > [-Wsometimes-uninitialized]
> > > > > for (i = 0; i < opencl_ctx.kernel_code_count; i++) {
> > > > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > > > libavutil/opencl.c:466:10: note: uninitialized use occurs here
> > > > > if (!kernel_source) {
> > > > > ^~~~~~~~~~~~~
> > > > > libavutil/opencl.c:456:17: note: remove the condition if it is always
> > > > true
> > > > > for (i = 0; i < opencl_ctx.kernel_code_count; i++) {
> > > > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > > > libavutil/opencl.c:448:30: note: initialize the variable
> > 'kernel_source'
> > > > to
> > > > > silence this warning
> > > > > const char *kernel_source;
> > > > > ^
> > > > > = NULL
> > > >
> > > > > libavcodec/cfhd.c | 6 +++---
> > > > > libavcodec/dv_tablegen.c | 2 +-
> > > > > libavfilter/af_hdcd.c | 2 +-
> > > > > libavfilter/vf_hwdownload.c | 6 ++++--
> > > > > libavutil/opencl.c | 2 +-
> > > >
> > > > please split this patch
> > > > the fixed warnings are unrelated to each other and possibly differnt
> > > > developers would like to reply to different parts
> > > >
> > > > [...]
> > > >
> > > > --
> > > > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> > > >
> > > > I have often repented speaking, but never of holding my tongue.
> > > > -- Xenocrates
> > > > _______________________________________________
> > > > ffmpeg-devel mailing list
> > > > ffmpeg-devel at ffmpeg.org
> > > > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > > >
> >
> > > af_hdcd.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > 0ff76093ae99c1ef8ae87b70d8bf5b6ef92c43b9
> > 0003-libavfilter-af_hdcd-fixed-negative-signed-value-shif.patch
> > > From c498d1a86f3cdbed94cc8bc4a9af7c87af03b275 Mon Sep 17 00:00:00 2001
> > > From: dsmudhar <ds.mudhar at gmail.com>
> > > Date: Sun, 22 May 2016 06:18:58 +0530
> > > Subject: [PATCH 3/7] libavfilter/af_hdcd: fixed negative signed value
> > shift
> > >
> > > ---
> > > libavfilter/af_hdcd.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/libavfilter/af_hdcd.c b/libavfilter/af_hdcd.c
> > > index 041b89f..fbf0836 100644
> > > --- a/libavfilter/af_hdcd.c
> > > +++ b/libavfilter/af_hdcd.c
> > > @@ -893,7 +893,7 @@ static int integrate(hdcd_state_t *state, int *flag,
> > const int32_t *samples, int
> > > state->code_counterC++;
> > > } else {
> > > if (bits)
> > > - state->readahead = readaheadtab[bits & ~(-1 << 8)];
> > > + state->readahead = readaheadtab[bits & ~((unsigned) -1 <<
> > 8)];
> > > else
> >
> > applied
>
>
> This is very obfuscated, why doesn't this just say bits & 0xff?
i dont know that
maybe the author of the original "& ~(-1 << 8)" or new code had a
reason to prefer this style
also obfuscation is in the eye of the beholder,
i would guess 0xff is only clearer if you know what it is in binary
if you dont then explicitly building it from a shift by 8 is clearer
i suspect
as far as iam conered iam fine with either with a slight preferrance
to 0xff unless the author(s) prefer something else
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety -- Benjamin Franklin
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