commit bf59038cac11798cbaef9f3bf965bad8182b97fa
author Denis Koroskin <dkoroskin@fb.com> Wed Mar 09 13:46:37 2022 -0800
committer GitHub <noreply@github.com> Wed Mar 09 13:46:37 2022 -0800
tree 298768c1b3e0063c8ed254957fe778d3f6650104
parent 348c3e31667ad0e73d3e0b19b372061c14ee8d58

Allow specifying additional target triples in rust_register_toolchains() and fix androideabi system (#1181)

* Allow specifying additional target triples in rust_register_toolchains() and fix androideabi system

In addition to host target, "wasm32-unknown-unknown" and "wasm32-wasi" targets are being installed, which includes downloading corresponding rust-std libraries. This CL allow specifying custom additional target triples by introducing a new parameter to rust_register_toolchains(), which defaults to ["wasm32-unknown-unknown" and "wasm32-wasi"] for compatibility. As an example, it is now possible to compile for Android if ["armv7-linux-androideabi"] is specified as an extra_target_triples.

Specifically for Android, most of the required infrastructure was already in place. For example, @rules_rust//rust/platform:triple_mappings.bzl already has all the necessary information to compile Android libraries (e.g. _SYSTEM_TO_STDLIB_LINKFLAGS). However, "armv7-linux-androideabi" is not a 'proper' target tripple because 'androideabi' is not a proper system. As such, special handling is required to map 'androideabi' back to 'android'.

* Extract common triple decomposition logic into a helper method that returns a struct with the fields populated.

* Use triple() function from triple.bzl

* Restore removed methods, and add deprecation message.

Co-authored-by: Denis Koroskin <dkoroskin@google.com>