Zld: Drop-in, faster version of Apple's linker

zld is also the name of the drop-in, faster, portable version of Apple's linker that got merged into Zig https://github.com/kubkon/zld

Note: this zld is completely written in Zig and it is a good example of Zig codebase of moderate size and complexity.

The codebase seems remarkably small. I expected linkers to take a lot more effort to write.

And yet, thanks to zld, Zig is the only C/C++ compiler that can link Apple Silicon Mach0 when cross-compiling from another platform.

Maybe somewhere in there there's a source of difficulty that doesn't directly translate to lines of code.

A lot of the complexity stems from supporting multiple platforms/versions/optimizations/build configs, though. ld64/zld supports 300+ CLI flags...

Also, LLD in trunk can link for Apple Silicon too :)

I would like to see a runoff between the two zlds. May the best Zld win!

How does this compare with LLD?

LLD's Mach-O backend is still in development. We'll definitely benchmark it against zld when it's ready. I think we can be little a bit faster...

Curious how this performs on a more complex codebase (eg linking llvm or chromium)

XUL (aka Firefox) is complex enough for me.