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mirror of https://github.com/FFmpeg/FFmpeg.git synced 2025-03-03 14:32:16 +02:00
FFmpeg/libavdevice/alldevices.c
Andreas Rheinhardt 7cf4c9037c avdevice/alldevices: Mark devices as hidden
Both GCC and Clang create code that inlines the loops in
next_input() and next_output() at high optimization
levels (presumably when there are not too many devices)
and this code leads to the creation of .got entries:
  e7:	48 3b 3d 00 00 00 00 	cmp    0x0(%rip),%rdi        # ee <av_input_video_device_next+0xe>
			ea: R_X86_64_REX_GOTPCRELX	ff_alsa_demuxer-0x4
  ee:	74 43                	je     133 <av_input_video_device_next+0x53>
  f0:	48 3b 3d 00 00 00 00 	cmp    0x0(%rip),%rdi        # f7 <av_input_video_device_next+0x17>
			f3: R_X86_64_REX_GOTPCRELX	ff_fbdev_demuxer-0x4
  f7:	74 41                	je     13a <av_input_video_device_next+0x5a>

These relocations can't be fixed up lateron when it is known
that the symbols exist in the same DSO.

This commit therefore marks these symbols as hidden, leading
to code like this:
  f7:	48 8d 05 00 00 00 00 	lea    0x0(%rip),%rax        # fe <av_input_video_device_next+0xe>
			fa: R_X86_64_PC32	ff_alsa_demuxer-0x4
  fe:	48 39 c7             	cmp    %rax,%rdi
 101:	74 55                	je     158 <av_input_video_device_next+0x68>
 103:	48 8d 05 00 00 00 00 	lea    0x0(%rip),%rax        # 10a <av_input_video_device_next+0x1a>
			106: R_X86_64_PC32	ff_fbdev_demuxer-0x4
 10a:	48 39 c7             	cmp    %rax,%rdi
 10d:	74 50                	je     15f <av_input_video_device_next+0x6f>

(Note: It is actually strange that the compiler creates code
that tries to read the addresses from the .got given that the
addresses can be read directly from indev_list/outdev_list.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2024-03-17 15:10:05 +01:00

145 lines
4.5 KiB
C

/*
* Register all the grabbing devices.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/attributes_internal.h"
#include "libavformat/demux.h"
#include "libavformat/internal.h"
#include "libavformat/mux.h"
#include "avdevice.h"
FF_VISIBILITY_PUSH_HIDDEN
/* devices */
extern const FFInputFormat ff_alsa_demuxer;
extern const FFOutputFormat ff_alsa_muxer;
extern const FFInputFormat ff_android_camera_demuxer;
extern const FFOutputFormat ff_audiotoolbox_muxer;
extern const FFInputFormat ff_avfoundation_demuxer;
extern const FFInputFormat ff_bktr_demuxer;
extern const FFOutputFormat ff_caca_muxer;
extern const FFInputFormat ff_decklink_demuxer;
extern const FFOutputFormat ff_decklink_muxer;
extern const FFInputFormat ff_dshow_demuxer;
extern const FFInputFormat ff_fbdev_demuxer;
extern const FFOutputFormat ff_fbdev_muxer;
extern const FFInputFormat ff_gdigrab_demuxer;
extern const FFInputFormat ff_iec61883_demuxer;
extern const FFInputFormat ff_jack_demuxer;
extern const FFInputFormat ff_kmsgrab_demuxer;
extern const FFInputFormat ff_lavfi_demuxer;
extern const FFInputFormat ff_openal_demuxer;
extern const FFOutputFormat ff_opengl_muxer;
extern const FFInputFormat ff_oss_demuxer;
extern const FFOutputFormat ff_oss_muxer;
extern const FFInputFormat ff_pulse_demuxer;
extern const FFOutputFormat ff_pulse_muxer;
extern const FFOutputFormat ff_sdl2_muxer;
extern const FFInputFormat ff_sndio_demuxer;
extern const FFOutputFormat ff_sndio_muxer;
extern const FFInputFormat ff_v4l2_demuxer;
extern const FFOutputFormat ff_v4l2_muxer;
extern const FFInputFormat ff_vfwcap_demuxer;
extern const FFInputFormat ff_xcbgrab_demuxer;
extern const FFOutputFormat ff_xv_muxer;
/* external libraries */
extern const FFInputFormat ff_libcdio_demuxer;
extern const FFInputFormat ff_libdc1394_demuxer;
FF_VISIBILITY_POP_HIDDEN
#include "libavdevice/outdev_list.c"
#include "libavdevice/indev_list.c"
void avdevice_register_all(void)
{
avpriv_register_devices(outdev_list, indev_list);
}
static const void *next_input(const AVInputFormat *prev, AVClassCategory c2)
{
const AVClass *pc;
const AVClassCategory c1 = AV_CLASS_CATEGORY_DEVICE_INPUT;
AVClassCategory category = AV_CLASS_CATEGORY_NA;
const FFInputFormat *fmt = NULL;
int i = 0;
while (prev && (fmt = indev_list[i])) {
i++;
if (prev == &fmt->p)
break;
}
do {
fmt = indev_list[i++];
if (!fmt)
break;
pc = fmt->p.priv_class;
if (!pc)
continue;
category = pc->category;
} while (category != c1 && category != c2);
return fmt;
}
static const void *next_output(const AVOutputFormat *prev, AVClassCategory c2)
{
const AVClass *pc;
const AVClassCategory c1 = AV_CLASS_CATEGORY_DEVICE_OUTPUT;
AVClassCategory category = AV_CLASS_CATEGORY_NA;
const FFOutputFormat *fmt = NULL;
int i = 0;
while (prev && (fmt = outdev_list[i])) {
i++;
if (prev == &fmt->p)
break;
}
do {
fmt = outdev_list[i++];
if (!fmt)
break;
pc = fmt->p.priv_class;
if (!pc)
continue;
category = pc->category;
} while (category != c1 && category != c2);
return fmt;
}
const AVInputFormat *av_input_audio_device_next(const AVInputFormat *d)
{
return next_input(d, AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT);
}
const AVInputFormat *av_input_video_device_next(const AVInputFormat *d)
{
return next_input(d, AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT);
}
const AVOutputFormat *av_output_audio_device_next(const AVOutputFormat *d)
{
return next_output(d, AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT);
}
const AVOutputFormat *av_output_video_device_next(const AVOutputFormat *d)
{
return next_output(d, AV_CLASS_CATEGORY_DEVICE_VIDEO_OUTPUT);
}