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Implement the MCP 932: Promote riscv64a23-unknown-linux-gnu to Tier 2 #148435

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4 changes: 2 additions & 2 deletions compiler/rustc_target/src/spec/targets/riscv64a23_unknown_linux_gnu.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,8 +7,8 @@ pub(crate) fn target() -> Target {
llvm_target: "riscv64-unknown-linux-gnu".into(),
metadata: TargetMetadata {
description: Some("RISC-V Linux (kernel 6.8.0, glibc 2.39)".into()),
tier: Some(3),
host_tools: Some(true),
tier: Some(2),
host_tools: Some(false),
std: Some(true),
},
pointer_width: 64,
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8 changes: 6 additions & 2 deletions src/ci/docker/host-x86_64/dist-riscv64-linux/Dockerfile
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Expand Up @@ -22,9 +22,13 @@ ENV PATH=$PATH:/x-tools/riscv64-unknown-linux-gnu/bin

ENV CC_riscv64gc_unknown_linux_gnu=riscv64-unknown-linux-gnu-gcc \
AR_riscv64gc_unknown_linux_gnu=riscv64-unknown-linux-gnu-ar \
CXX_riscv64gc_unknown_linux_gnu=riscv64-unknown-linux-gnu-g++
CXX_riscv64gc_unknown_linux_gnu=riscv64-unknown-linux-gnu-g++ \
CC_riscv64a23_unknown_linux_gnu=riscv64-unknown-linux-gnu-gcc \
AR_riscv64a23_unknown_linux_gnu=riscv64-unknown-linux-gnu-ar \
CXX_riscv64a23_unknown_linux_gnu=riscv64-unknown-linux-gnu-g++

ENV HOSTS=riscv64gc-unknown-linux-gnu
ENV TARGETS=riscv64gc-unknown-linux-gnu,riscv64a23-unknown-linux-gnu

ENV RUST_CONFIGURE_ARGS --enable-extended --enable-profiler --disable-docs
ENV SCRIPT python3 ../x.py dist --target $HOSTS --host $HOSTS
ENV SCRIPT python3 ../x.py dist --target $TARGETS --host $HOSTS
20 changes: 11 additions & 9 deletions src/doc/rustc/src/platform-support/riscv64a23-unknown-linux-gnu.md
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@@ -1,6 +1,6 @@
# `riscv64a23-unknown-linux-gnu`

**Tier: 3**
**Tier: 2 (without Host Tools)**

RISC-V target using the ratified [RVA23 Profile](https://github.com/riscv/riscv-profiles/blob/main/src/rva23-profile.adoc).
This target will enable all mandary features of rva23u64 by default.
Expand All @@ -18,24 +18,26 @@ Other platforms may work, but are not tested. Please contanct if you encounter a

## Building the target

Tier-3 target is not distributed through `rustup`.

You need to build your own Rust, the target can be build with:
Tier-2 targets are distributed through `rustup`. Install the target with:

```bash
./x build --target riscv64a23-unknown-linux-gnu
rustup target add riscv64a23-unknown-linux-gnu
```

## Building Rust programs

Add the toolchain:
Cross compile crates with:

```bash
rustup toolchain link rva23-toolchain {path-to-rust}/build/host/stage2
cargo build --target=riscv64a23-unknown-linux-gnu
```

Then cross compile crates with:
For cross-compilation, you may need to install the appropriate linker:

```bash
RUSTFLAGS="-C linker=riscv64-linux-gnu-gcc" cargo +rva23-toolchain build --target=riscv64a23-unknown-linux-gnu
# Ubuntu/Debian
sudo apt-get install gcc-riscv64-linux-gnu

# Then set the linker
RUSTFLAGS="-C linker=riscv64-linux-gnu-gcc" cargo build --target=riscv64a23-unknown-linux-gnu
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@Urgau Urgau Nov 3, 2025 •
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Does the target work with lld? If so, it may be better to set rust-lld as the default linker instead asking users to use an external linker.

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@ZhongyaoChen ZhongyaoChen Nov 4, 2025

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Thanks for the review!
This target works with rust-lld. From my understanding, the default linker should be configured by targets that provide host tools for cross-compilation, rather than by the target itself. If I'm wrong about this, please share more guidance.

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@Urgau Urgau Nov 4, 2025

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Well, looking at our target definitions many of have linker: Some("rust-lld".into()) set and most of them do not provide host tools, including some RISC-V targets123. So I think it would make for this target to also set rust-lld as it's default linker.

Footnotes

  1. https://github.com/rust-lang/rust/blob/e5efc336720901420a8891dcdb67ca0a475dc03c/compiler/rustc_target/src/spec/targets/riscv32e_unknown_none_elf.rs#L23-L24 ↩

  2. https://github.com/rust-lang/rust/blob/e5efc336720901420a8891dcdb67ca0a475dc03c/compiler/rustc_target/src/spec/targets/riscv32emc_unknown_none_elf.rs#L23-L24 ↩

  3. https://github.com/rust-lang/rust/blob/e5efc336720901420a8891dcdb67ca0a475dc03c/compiler/rustc_target/src/spec/targets/riscv32imac_unknown_xous_elf.rs#L20-L21 ↩

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@ZhongyaoChen ZhongyaoChen Nov 5, 2025

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These are all bare-metal targets. In contrast, Linux targets like riscv64gc-unknown-linux-gnu, x86_64-unknown-linux-gnu, and aarch64-unknown-linux-gnu do not set rust-lld as default.

So I'm quite confused now.

```
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