rust/compiler/rustc_target
Matthias Krüger 1762f018f7
Rollup merge of #137860 - taiki-e:powerpcspe-msync, r=workingjubilee
rustc_target: Add msync target feature and enable it on powerpcspe targets

Some older PowerPC processors do not have the `sync` (`sync 0`) and `lwsync` (`sync 1`) instructions, but instead have the `msync` instruction. (IIRC `msync` and `sync` will be assembled into the same bit-pattern, but `lwsync` will be SIGILL. See also https://gcc.gnu.org/legacy-ml/gcc-patches/2006-11/msg01238.html.)

LLVM recognizes this as the [`msync` feature](cc5d8a4b2f/llvm/lib/Target/PowerPC/PPC.td (L140)) and enables for some cpus such as [e500](cc5d8a4b2f/llvm/lib/Target/PowerPC/PPC.td (L644)).

powerpcspe is a target for CPUs such as e500 ([Debian Wiki](https://wiki.debian.org/PowerPCSPEPort)). However, the `msync` feature is currently not enabled except for vxworks, and at least since 2022-04, powerpc-unknown-linux-gnuspe was known to not work on real hardware without `-C target-cpu` (e.g., #96394, #117361).

8c392966a0/compiler/rustc_target/src/spec/targets/powerpc_wrs_vxworks_spe.rs (L28)

Fixes #117361

cc `@BKPepe` ([powerpc-unknown-linux-muslspe target maintainer](https://doc.rust-lang.org/nightly/rustc/platform-support/powerpc-unknown-linux-muslspe.html#target-maintainers))
cc `@glaubitz` (who added powerpc-unknown-linux-gnuspe in https://github.com/rust-lang/rust/pull/48484)
cc `@th0ma7` (who opened #117361)

r? workingjubilee

`@rustbot` label +O-PowerPC +A-target-feature
2025-03-02 22:44:25 +01:00
..
src Rollup merge of #137860 - taiki-e:powerpcspe-msync, r=workingjubilee 2025-03-02 22:44:25 +01:00
Cargo.toml Upgrade the compiler to edition 2024 2025-02-22 00:01:48 +00:00
README.md Fix outdated crate names in compiler docs 2021-04-08 11:12:14 -05:00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.