rust/compiler/rustc_target
bors b6685d748f Auto merge of #141435 - RalfJung:unsupported_calling_conventions, r=workingjubilee
Add (back) `unsupported_calling_conventions` lint to reject more invalid calling conventions

This adds back the `unsupported_calling_conventions` lint that was removed in https://github.com/rust-lang/rust/pull/129935, in order to start the process of dealing with https://github.com/rust-lang/rust/issues/137018. Specifically, we are going for the plan laid out [here](https://github.com/rust-lang/rust/issues/137018#issuecomment-2672118326):
- thiscall, stdcall, fastcall, cdecl should only be accepted on x86-32
- vectorcall should only be accepted on x86-32 and x86-64

The difference to the status quo is that:
- We stop accepting stdcall, fastcall on targets that are windows && non-x86-32 (we already don't accept these on targets that are non-windows && non-x86-32)
- We stop accepting cdecl on targets that are non-x86-32
- (There is no difference for thiscall, this was already a hard error on non-x86-32)
- We stop accepting vectorcall on targets that are windows && non-x86-*

Vectorcall is an unstable ABI so we can just make this a hard error immediately. The others are stable, so we emit the `unsupported_calling_conventions` forward-compat lint. I set up the lint to show up in dependencies via cargo's future-compat report immediately, but we could also make it show up just for the local crate first if that is preferred.

try-job: i686-msvc-1
try-job: x86_64-msvc-1
try-job: test-various
2025-06-09 05:21:49 +00:00
..
src Auto merge of #141435 - RalfJung:unsupported_calling_conventions, r=workingjubilee 2025-06-09 05:21:49 +00:00
Cargo.toml Bump object 2025-06-05 07:59:51 +08:00
README.md Fix outdated crate names in compiler docs 2021-04-08 11:12:14 -05:00

rustc_target contains some very low-level details that are specific to different compilation targets and so forth.

For more information about how rustc works, see the rustc dev guide.