It looks to me like this is the dyld start code https://github.com/apple-opensource/dyld/blob/e3f88907bebb8421f50f0943595f6874de70ebe0/src/dyldInitialization.cpp#L130 As one might expect it just walks over the env pointers plus one NULL to get to the apple pointer.

Code merged, now working on macOS 11. The next "big thing" will be arm64 support.

If all goes well I'll push the code for 10.15 tonight and then move on to macOS 11.

I've mostly fixed the issue. It is a problem related to _DATA_CONST. Valgrind needs to be updated so that when the __DATA_CONST load command is handled it shouldn't trigger debuginfo reading. That should happen on the next load command (normally __DATA).

Missed a zero from the end of the link https://bugs.kde.org/show_bug.cgi?id=437790