__zig_probe_stack undefined in static libraries

[jedisct1]

When building static libraries, the __zig_probe_stack symbol is undefined:

Undefined symbols for architecture x86_64:
  "___zig_probe_stack", referenced from:
      _std.debug.printLineInfo in x.o)
      _std.sort.sort in x.o)
ld: symbol(s) not found for architecture x86_64

Passing -fno-stack-check fixes this (thanks @FireFox317 !), but maybe stack checking should be disabled automatically when building static libraries. Or maybe we want to link compile_rt?

What would be the best way to improve this?

[LemonBoy]

maybe stack checking should be disabled automatically when building static libraries

That's not a good idea, isn't it? Silently turning off safety measures is not nice.
Two possible solutions are to always link in compiler-rt or build the stack probe function as a separate object that's unconditionally linked in.
The former is easier to implement but it will increase the size of the generated libraries for no good reason: when a Zig static library is linked against some other Zig code we still use our compile_rt implementation, whenever you link the library with some C object we still have libgcc or LLVM's compiler_rt to fall-back on. On the other hand relying on a third-party library provided by the C compiler means we may end up with missing symbols or with a copy afected by bugs we can't fix (it hasn't happened so far as our implementations were the buggy ones but it's definitely something to take into account).

[andrewrk]

we may end up with missing symbols or with a copy afected by bugs we can't fix (it hasn't happened so far as our implementations were the buggy ones but it's definitely something to take into account).

It has happened - here are a couple examples: e3ea0b6 9153681

It looks like I regressed --bundle-compiler-rt in #6250. There is even still a build.zig API that sets the flag, only to get a CLI error. Fixing that should address the issue here. I think the only thing left would be whether to re-evaluate the logic for the default value of this flag.

[andrewrk]

Now you can pass -fcompiler-rt to include compiler-rt in static libraries. Feel free to open a proposal to change the default, which is currently only dynamic libraries and executables get compiler-rt included.

After #7264 you would be able to also do this to get a compiler_rt object (or library): zig build-obj -fcompiler-rt / zig build-lib -fcompiler-rt.