[FFmpeg-devel] [inline assembly compliance] Issues and patches

[Carl Eugen Hoyos]

Am Fr., 3. Apr. 2020 um 22:42 Uhr schrieb FRÉDÉRIC RECOULES
<frederic.recoules at univ-grenoble-alpes.fr>:

> we are academic researchers working in automated program analysis.
> We are currently interested in checking compliance of inline asm chunks
> as found in C programs.
>
> While benchmarking our tool and technique, we found a number of issues in
> FFMPEG. We report them to you, as well as adequate patches.
> Actually, we found 59 significant compliance issues in your code.
> We join 3 patches for some of them, together with explanations and
> we can send you other patches on demand.
>
>
> * All these bugs are related to compliance between the block of asm and its
> surrounding "contract" (in gcc-style notation). They are akin to undefined or
> implementation-defined behaviours in C: they currently do not manifest
> themselves in your program, but at some point in time with compiler
> optimizations becoming more and more aggressive or changes in undocumented
> compiler choices regarding asm chunks, they can suddenly trigger a
> (hard-to-find) bug.

So your current patch does not change compilation output (without
debug symbols) when compared with md5sum or similar?

We only accept patches made with git format-patch, no diff files.

Carl Eugen