riscv32imac-unknown-xous-elf: add target

compiler/rustc_target/src/spec/mod.rs

@@ -983,6 +983,7 @@ supported_targets! {
     ("riscv32imc-unknown-none-elf", riscv32imc_unknown_none_elf),
     ("riscv32imc-esp-espidf", riscv32imc_esp_espidf),
     ("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
+    ("riscv32imac-unknown-xous-elf", riscv32imac_unknown_xous_elf),
     ("riscv32gc-unknown-linux-gnu", riscv32gc_unknown_linux_gnu),
     ("riscv32gc-unknown-linux-musl", riscv32gc_unknown_linux_musl),
     ("riscv64imac-unknown-none-elf", riscv64imac_unknown_none_elf),

compiler/rustc_target/src/spec/riscv32imac_unknown_xous_elf.rs

@@ -0,0 +1,24 @@
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, RelocModel};
+use crate::spec::{Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S128".into(),
+        llvm_target: "riscv32".into(),
+        pointer_width: 32,
+        arch: "riscv32".into(),
+
+        options: TargetOptions {
+            os: "xous".into(),
+            linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
+            linker: Some("rust-lld".into()),
+            cpu: "generic-rv32".into(),
+            max_atomic_width: Some(32),
+            features: "+m,+a,+c".into(),
+            executables: true,
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: RelocModel::Static,
+            ..Default::default()
+        },
+    }
+}

src/doc/rustc/src/SUMMARY.md

@@ -22,6 +22,7 @@
     - [m68k-unknown-linux-gnu](platform-support/m68k-unknown-linux-gnu.md)
     - [mips64-openwrt-linux-musl](platform-support/mips64-openwrt-linux-musl.md)
     - [nvptx64-nvidia-cuda](platform-support/nvptx64-nvidia-cuda.md)
+    - [riscv32imac-unknown-xous-elf](platform-support/riscv32imac-unknown-xous-elf.md)
     - [*-pc-windows-gnullvm](platform-support/pc-windows-gnullvm.md)
     - [*-unknown-openbsd](platform-support/openbsd.md)
     - [wasm64-unknown-unknown](platform-support/wasm64-unknown-unknown.md)

src/doc/rustc/src/platform-support.md

@@ -275,6 +275,7 @@ target | std | host | notes
 `riscv32gc-unknown-linux-gnu` |   |   | RISC-V Linux (kernel 5.4, glibc 2.33)
 `riscv32gc-unknown-linux-musl` |   |   | RISC-V Linux (kernel 5.4, musl + RISCV32 support patches)
 `riscv32im-unknown-none-elf` | * |  | Bare RISC-V (RV32IM ISA)
+[`riscv32imac-unknown-xous-elf`](platform-support/riscv32imac-unknown-xous-elf.md) | ? |  | RISC-V Xous (RV32IMAC ISA)
 `riscv32imc-esp-espidf` | ✓ |  | RISC-V ESP-IDF
 `riscv64gc-unknown-freebsd` |   |   | RISC-V FreeBSD
 `riscv64gc-unknown-linux-musl` |   |   | RISC-V Linux (kernel 4.20, musl 1.2.0)

src/doc/rustc/src/platform-support/riscv32imac-unknown-xous-elf.md

@@ -0,0 +1,50 @@
+# riscv32imac-unknown-xous-elf
+
+**Tier: 3**
+
+Xous microkernel, message-based operating system that powers devices such as Precursor and Betrusted. The operating system is written entirely in Rust, so no additional software is required to compile programs for Xous.
+
+## Target maintainers
+
+- [@xobs](https://github.com/xobs)
+
+## Requirements
+
+
+Building the target itself requires a RISC-V compiler that is supported by `cc-rs`. For example, you can use the prebuilt [xPack](https://github.com/xpack-dev-tools/riscv-none-elf-gcc-xpack/releases/latest) toolchain.
+
+Cross-compiling programs does not require any additional software beyond the toolchain. Prebuilt versions of the toolchain are available [from Betrusted](https://github.com/betrusted-io/rust/releases).
+
+## Building the target
+
+The target can be built by enabling it for a `rustc` build.
+
+```toml
+[build]
+target = ["riscv32imac-unknown-xous-elf"]
+```
+
+Make sure your C compiler is included in `$PATH`, then add it to the `config.toml`:
+
+```toml
+[target.riscv32imac-unknown-xous-elf]
+cc = "riscv-none-elf-gcc"
+ar = "riscv-none-elf-ar"
+```
+
+## Building Rust programs
+
+Rust does not yet ship pre-compiled artifacts for this target. To compile for
+this target, you will need to do one of the following:
+
+* Build Rust with the target enabled (see "Building the target" above)
+* Build your own copy of `core` by using `build-std` or similar
+* Download a prebuilt toolchain [from Betrusted](https://github.com/betrusted-io/rust/releases)
+
+## Cross-compilation
+
+This target can be cross-compiled from any host.
+
+## Testing
+
+Currently there is no support to run the rustc test suite for this target.

src/test/ui/check-cfg/well-known-values.stderr

@@ -7,7 +7,7 @@ LL | #[cfg(target_os = "linuz")]
    |                   help: did you mean: `"linux"`
    |
    = note: `#[warn(unexpected_cfgs)]` on by default
-   = note: expected values for `target_os` are: android, cuda, dragonfly, emscripten, espidf, freebsd, fuchsia, haiku, hermit, horizon, illumos, ios, l4re, linux, macos, netbsd, none, openbsd, psp, redox, solaris, solid_asp3, tvos, uefi, unknown, vxworks, wasi, windows
+   = note: expected values for `target_os` are: android, cuda, dragonfly, emscripten, espidf, freebsd, fuchsia, haiku, hermit, horizon, illumos, ios, l4re, linux, macos, netbsd, none, openbsd, psp, redox, solaris, solid_asp3, tvos, uefi, unknown, vxworks, wasi, windows, xous
 
 warning: unexpected `cfg` condition value
   --> $DIR/well-known-values.rs:14:7