Always output a tarball from cc_binary to simplify logic.

[walkingeyerobot]

This will change the result of --config=wasm builds that were previously outputting a single file.

Helps prepare for windows support (#814) and removes the need for #929 to add an external python dep.

[walkingeyerobot]

cc @trybka

[sbc100]

Its maybe a little sad that --config=wasm a little less directly useful now since users will always need to untar the wasm file. I guess it will push more folks towards using wasm_cc_binaryen?

[sbc100]

Can we just drop this if/else completely. If you a worried that would loose coverage perhaps just assert(len(files)) here?

[walkingeyerobot]

Yeah, I would prefer to maintain the check. I don't expect it to be triggered, but we're not losing anything by keeping it, so I figure it's better to keep it.

[sbc100]

OK, but then at least re-write it to use early-return style and avoid the indentation:

if not len(files):
  print('emcc.py did not appear to output any known files!')
  sys.exit(1)

.. the rest here without any indentation

[walkingeyerobot]

Done

[walkingeyerobot]

Its maybe a little sad that --config=wasm a little less directly useful now since users will always need to untar the wasm file. I guess it will push more folks towards using wasm_cc_binaryen?

Hopefully it will. I believe the majority of emscripten users are building and using both the .wasm file and the .js wrapper, so this should affect a very small number of users. It's not too bad to generate a genrule that would untar the archive for you if someone is insistent in not using wasm_cc_binary. And if this does generate enough complaints, we can always go back and add the filetype dep.

In short, this simplifies the code, eliminates a potential external dependency, and shouldn't affect very many users.

[trybka]

cc @trybka

LGTM (with sbc100's suggested tweak)

[walkingeyerobot]

not sure why the test-linux check is failing; what I did shouldn't have any effect there.

[sbc100]

Looks like an unrelated binaryen failure:

root/project/binaryen/main/src/passes/GlobalRefining.cpp: In member function 'virtual void wasm::{anonymous}::GlobalRefining::run(wasm::PassRunner*, wasm::Module*)':
/root/project/binaryen/main/src/passes/GlobalRefining.cpp:57:27: error: unused variable 'func' [-Werror=unused-variable]
     for (auto& [func, info] : analysis.map) 

[walkingeyerobot]

Looks like an unrelated binaryen failure:

Ok, thanks! Let me know if there's anything else I should do to get this merged. Happy to wait and rebase if necessary. :)

[walkingeyerobot]

Looks like this is still failing. Is there something I need to update to get it to pass?

[sbc100]

I think you just need to rebase (or merge), no?

[walkingeyerobot]

Thanks! Sorry about that, my git experience is still quite minimal. I just need an approval now please and thanks!