avcodec/cbs_h2645: Avoid function pointer casts, fix UB

The SEI message read/write functions are called
via function pointers where the SEI message-specific
context is passed as void*. But the actual function
definitions use a pointer to their proper context
in place of void*, making the calls undefined behaviour.
Clang UBSan 17 warns about this.

This commit fixes this by adding wrapper functions
(created via macros) that have the right type that
call the actual functions. This reduced the number of failing
FATE tests with UBSan from 164 to 85 here.

Reviewed-by: Mark Thompson <sw@jkqxz.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 0 insertions, 7 deletions

diff --git a/libavcodec/cbs_sei.h b/libavcodec/cbs_sei.h
index 4511c506cc..ec7cdb62f0 100644
--- a/libavcodec/cbs_sei.h
+++ b/libavcodec/cbs_sei.h
@@ -126,13 +126,6 @@ typedef struct SEIMessageTypeDescriptor {
     SEIMessageWriteFunction write;
 } SEIMessageTypeDescriptor;
 
-// Macro for the read/write pair.  The clumsy cast is needed because the
-// current pointer is typed in all of the read/write functions but has to
-// be void here to fit all cases.
-#define SEI_MESSAGE_RW(codec, name) \
-    .read  = (SEIMessageReadFunction) cbs_ ## codec ## _read_  ## name, \
-    .write = (SEIMessageWriteFunction)cbs_ ## codec ## _write_ ## name
-
 // End-of-list sentinel element.
 #define SEI_MESSAGE_TYPE_END { .type = -1 }