[FFmpeg-devel] [PATCH] avcodec/refstruct: Don't use STRIDE_ALIGN for alignment

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Thu Feb 29 11:36:06 EET 2024


Andreas Rheinhardt:
> It was always intended that the buffers returned by
> RefStruct shall have the same alignment guarantees
> as the buffers returned by av_malloc(); said alignment
> depends upon the arch and the enabled instruction set
> and the code used STRIDE_ALIGN as a proxy for this.
> 
> Yet since 7945d30e91b96d2f4f5b612048169087d214d41e
> there is a better way to get av_malloc's alignment:
> ALIGN_64 in mem_internal.h. So use this.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
>  libavcodec/refstruct.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/refstruct.c b/libavcodec/refstruct.c
> index 81e8c9795c..f89af156c2 100644
> --- a/libavcodec/refstruct.c
> +++ b/libavcodec/refstruct.c
> @@ -20,13 +20,13 @@
>  #include <stdint.h>
>  #include <string.h>
>  
> -#include "internal.h"
>  #include "refstruct.h"
>  
>  #include "libavutil/avassert.h"
>  #include "libavutil/error.h"
>  #include "libavutil/macros.h"
>  #include "libavutil/mem.h"
> +#include "libavutil/mem_internal.h"
>  #include "libavutil/thread.h"
>  
>  #ifndef REFSTRUCT_CHECKED
> @@ -46,9 +46,9 @@
>                                 MKTAG('R', 'e', 'f', 'S') | (uint64_t)MKTAG('t', 'r', 'u', 'c') << 32)
>  
>  #if __STDC_VERSION__ >= 201112L && !defined(_MSC_VER)
> -#define REFCOUNT_OFFSET FFALIGN(sizeof(RefCount), FFMAX3(STRIDE_ALIGN, 16, _Alignof(max_align_t)))
> +#define REFCOUNT_OFFSET FFALIGN(sizeof(RefCount), FFMAX(ALIGN_64, _Alignof(max_align_t)))
>  #else
> -#define REFCOUNT_OFFSET FFALIGN(sizeof(RefCount), FFMAX(STRIDE_ALIGN, 16))
> +#define REFCOUNT_OFFSET FFALIGN(sizeof(RefCount), ALIGN_64)
>  #endif
>  
>  typedef struct RefCount {

Will apply this patch tomorrow unless there are objections.

- Andreas



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