[FFmpeg-devel] [PATCH 8/8] avcodec/codec_internal: Include codec_tags only when they are needed

[Andreas Rheinhardt]

Andreas Rheinhardt:
> They are only needed for the fuzzer, so check for CONFIG_OSSFUZZ.
> This decreases sizeof(FFCodec), which is important given that
> FFCodecs reside in .data.rel.ro in case of ELF with
> position-independent code which is always loaded and can't be shared
> between processes.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
>  libavcodec/bitpacked_dec.c  |  5 +----
>  libavcodec/codec_internal.h | 10 ++++++++++
>  libavcodec/hapdec.c         | 13 +++++--------
>  tools/target_dec_fuzzer.c   |  2 ++
>  4 files changed, 18 insertions(+), 12 deletions(-)
> 
> diff --git a/libavcodec/bitpacked_dec.c b/libavcodec/bitpacked_dec.c
> index 419550dfe0..b62d88fa8f 100644
> --- a/libavcodec/bitpacked_dec.c
> +++ b/libavcodec/bitpacked_dec.c
> @@ -151,9 +151,6 @@ const FFCodec ff_bitpacked_decoder = {
>      .init = bitpacked_init_decoder,
>      .decode = bitpacked_decode,
>      .p.capabilities = AV_CODEC_CAP_FRAME_THREADS,
> -    .codec_tags     = (const uint32_t []){
> -        MKTAG('U', 'Y', 'V', 'Y'),
> -        FF_CODEC_TAGS_END,
> -    },
>      .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
> +    FF_CODEC_TAGS(MKTAG('U', 'Y', 'V', 'Y'))
>  };
> diff --git a/libavcodec/codec_internal.h b/libavcodec/codec_internal.h
> index 596cdbebd2..b6b5b05b44 100644
> --- a/libavcodec/codec_internal.h
> +++ b/libavcodec/codec_internal.h
> @@ -21,6 +21,7 @@
>  
>  #include <stdint.h>
>  
> +#include "config.h"
>  #include "libavutil/attributes.h"
>  #include "codec.h"
>  
> @@ -74,10 +75,16 @@
>   */
>  #define FF_CODEC_CAP_SETS_FRAME_PROPS       (1 << 8)
>  
> +#if CONFIG_OSSFUZZ
>  /**
>   * FFCodec.codec_tags termination value
>   */
>  #define FF_CODEC_TAGS_END -1
> +#define FF_CODEC_TAGS(...) \
> +    .codec_tags = (const uint32_t[]){ __VA_ARGS__, FF_CODEC_TAGS_END },
> +#else
> +#define FF_CODEC_TAGS(...)
> +#endif
>  
>  typedef struct FFCodecDefault {
>      const char *key;
> @@ -196,10 +203,13 @@ typedef struct FFCodec {
>       */
>      const struct AVCodecHWConfigInternal *const *hw_configs;
>  
> +#if CONFIG_OSSFUZZ
>      /**
>       * List of supported codec_tags, terminated by FF_CODEC_TAGS_END.
> +     * Should be defined with the FF_CODEC_TAGS() macro.
>       */
>      const uint32_t *codec_tags;
> +#endif
>  } FFCodec;
>  
>  static av_always_inline const FFCodec *ffcodec(const AVCodec *codec)
> diff --git a/libavcodec/hapdec.c b/libavcodec/hapdec.c
> index 4a7ac15a8e..72f922bc5b 100644
> --- a/libavcodec/hapdec.c
> +++ b/libavcodec/hapdec.c
> @@ -486,12 +486,9 @@ const FFCodec ff_hap_decoder = {
>                        AV_CODEC_CAP_DR1,
>      .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE |
>                        FF_CODEC_CAP_INIT_CLEANUP,
> -    .codec_tags     = (const uint32_t []){
> -        MKTAG('H','a','p','1'),
> -        MKTAG('H','a','p','5'),
> -        MKTAG('H','a','p','Y'),
> -        MKTAG('H','a','p','A'),
> -        MKTAG('H','a','p','M'),
> -        FF_CODEC_TAGS_END,
> -    },
> +    FF_CODEC_TAGS(MKTAG('H','a','p','1'),
> +                  MKTAG('H','a','p','5'),
> +                  MKTAG('H','a','p','Y'),
> +                  MKTAG('H','a','p','A'),
> +                  MKTAG('H','a','p','M'))
>  };
> diff --git a/tools/target_dec_fuzzer.c b/tools/target_dec_fuzzer.c
> index 288aa63313..77f4bb8dd8 100644
> --- a/tools/target_dec_fuzzer.c
> +++ b/tools/target_dec_fuzzer.c
> @@ -279,12 +279,14 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
>          ctx->sample_rate                        = bytestream2_get_le32(&gbc) & 0x7FFFFFFF;
>          ctx->ch_layout.nb_channels              = (unsigned)bytestream2_get_le32(&gbc) % FF_SANE_NB_CHANNELS;
>          ctx->block_align                        = bytestream2_get_le32(&gbc) & 0x7FFFFFFF;
> +#if CONFIG_OSSFUZZ
>          ctx->codec_tag                          = bytestream2_get_le32(&gbc);
>          if (c->codec_tags) {
>              int n;
>              for (n = 0; c->codec_tags[n] != FF_CODEC_TAGS_END; n++);
>              ctx->codec_tag = c->codec_tags[ctx->codec_tag % n];
>          }
> +#endif
>          keyframes                               = bytestream2_get_le64(&gbc);
>          request_channel_layout                  = bytestream2_get_le64(&gbc);
>  

Will apply tomorrow unless there are objections.

- Andreas