Andreas Rheinhardt: > Common symbols are not part of ISO-C and therefore not used > by FFmpeg at all. Yet linker warnings to ensure it stays > that way are nevertheless wrong, because the existence of > common symbols does not imply that there is a bug in our code. > > More precisely, Clang's ASAN implementation uses a common symbol > ___asan_globals_registered when used on Elf targets with > the -fsanitize-address-globals-dead-stripping option; > said option is the default since Clang 17 [1]. > This leads to 1883 warnings about ___asan_globals_registered > when linking here. > (Even without that option there were warnings like > _ZN14__interception10real_vforkE being overridden.) > > Said warning is also unnecessary: The proper way to ensure > that our code is free of common symbols is to let the compiler > enforce this. But this is already the default since GCC 10 > and Clang 11, so there is no risk of introducing our own > common symbols. > > [1]: https://reviews.llvm.org/D152604 > > Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com> > --- > There is btw a second incompatibility between our configure script > and Clang ASAN: Since version 16 it defaults to > -fsanitize-address-use-odr-indicator and with this option set, > it creates a __odr_asan_gen_FOO symbol for every object FOO > in addition to the symbol FOO itself; configure therefore sets > extern_prefix (used for ASM name mangling) to "__odr_asan_gen_". > > configure | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/configure b/configure > index 197f762b58..108816bd1e 100755 > --- a/configure > +++ b/configure > @@ -7337,7 +7337,6 @@ void (^block)(void); > EOF > > # add some linker flags > -check_ldflags -Wl,--warn-common > check_ldflags > -Wl,-rpath-link=:libpostproc:libswresample:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil > enabled rpath && add_ldexeflags -Wl,-rpath,$libdir && add_ldsoflags > -Wl,-rpath,$libdir > test_ldflags -Wl,-Bsymbolic && append SHFLAGS -Wl,-Bsymbolic
Will apply this patch tomorrow unless there are objections. - Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
