Generate import library without external tools

[messense]

I've take some time to port llvm-dlltool to Rust, implib-rs is a crate implements generating Windows import library from module definition file.

Unfortunately rust-ar doesn't support writing symbol table, so the currently it requires to run ranlib after generation to be useful. Thus it's not ready to be integrated in python3-dll-a right now. Hopefully someday we can find a solution to it.

I wonder how hard it is to port the mingw64 version, it'd be nice to support them both.

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Update: implib crate now produces the exact same .lib file like llvm-dlltool and it works for linking with lld with the this python3-dll-a patch:

[ravenexp]

Please keep in mind that RFC 2627 is still being actively worked on, and when it hits stable it will make hacks like xwin or python3-dll-a obsolete.

[messense]

Looks like the implementation of RFC 2627 does not support DATA: https://github.com/rust-lang/rust/blob/10913c00018c76103b2fd4260d8c02ec728fd244/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp#L1731 , will that be a problem for pyo3?

[ravenexp]

Yes, PyO3 uses quite a lot of DATA symbols for singletons like _Py_NoneStruct.

[messense]

And to support multiple Python versions and abi3 in pyo3-ffi, the link attributes are tedious with lots of cfgs.

#[link(name = "python3.dll", kind = "raw-dylib")]
#[link(name = "python37.dll", kind = "raw-dylib")]
#[link(name = "python38.dll", kind = "raw-dylib")]
#[link(name = "python39.dll", kind = "raw-dylib")]
#[link(name = "python310.dll", kind = "raw-dylib")]
#[link(name = "python311.dll", kind = "raw-dylib")]

And this MINGW Python dll name thing is annoying too.

[ravenexp]

Yes, code like that is best generated by the build script or a macro.