1478115 - Can't distinguish foreign functions in Rust that are defined in C++

Status: RESOLVED FIXED

(Webtools :: Searchfox, enhancement)

Description

[Emilio Cobos Álvarez [:emilio]]

It always pisses me off that I can't jump, e.g., from:

  https://searchfox.org/mozilla-central/rev/d160ac574a5798010eda4e33e91ee628aa268a33/servo/components/style/gecko_bindings/sugar/refptr.rs#292

To the C++ definition.

This happens because there's no way to differentiate:

extern "C" {
  fn MyFunc();
}

from:

fn MyFunc() {}.

I can hack on bindgen to manually add the no_mangle / link_name attribute so that  I can detect it, but it'd be even better to make it work in the general case, which is https://github.com/nrc/rls-data/issues/17

Comment 1

[Kartikaya Gupta (email:[e-mail])]

For reference, the mozsearch repo now has all the updated dependencies that it can add the special handling for DefKind::ForeignFunction and DefKind::ForeignStatic. However the save-analysis files are coming from the m-c taskcluster build, and those are being generated by (I think) rustc 1.28 at the moment, which doesn't yet have the RLS bump. I think that's in 1.30.0, so once m-c is getting compiled by 1.30 the special handling will "kick in".

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Looks like this works now. Can you confirm and close this bug if so?

Comment 3

[Emilio Cobos Álvarez [:emilio]]

Yes, I fixed this in https://github.com/mozsearch/mozsearch/pull/168.