Rust Stable for Xous

Build stable Rust binaries for Xous! This release targets Rust 1.73.0.

Supported Features

When porting the standard library to a new operating system, a piecemeal approach is taken. Features are gradually brought up as they are needed. So far, the following features work:

• println!()
• sync::Mutex
• sync::Condvar
• net::TcpStream
• net::UdpSocket
• net::LookupHost
• time::Duration
• time::Instant
• thread::sleep
• thread::spawn
• thread::local

Installing Prebuilt Releases

1. Ensure you are running Rust 1.73.0. Future versions of Rust will need a different version of this software.
2. Download the latest release from the releases page
3. Unzip the zipfile to your Rust sysroot. On Unix systems can do this with something like:

cd $(rustc --print sysroot)
wget https://github.com/betrusted-io/rust/releases/latest/download/riscv32imac-unknown-xous_1.73.0.zip
rm -rf lib/rustlib/riscv32imac-unknown-xous-elf # Remove any existing version
unzip *.zip
rm *.zip
cd -

On Windows with Powershell you can run:

Push-Location $(rustc --print sysroot)
if (Test-Path lib\rustlib\riscv32imac-unknown-xous-elf) { Remove-Item -Recurse -Force lib\rustlib\riscv32imac-unknown-xous-elf }
Invoke-WebRequest -Uri https://github.com/betrusted-io/rust/releases/latest/download/riscv32imac-unknown-xous_1.73.0.zip -Outfile toolchain.zip
Expand-Archive -DestinationPath . -Path toolchain.zip
Remove-Item toolchain.zip
Pop-Location

Building From Source

1. Install a RISC-V toolchain, and ensure it's in your path. Set CC and AR to point to the toolchain's -gcc and -ar binaries.
2. Set RUST_COMPILER_RT_ROOT to $(pwd)/src/llvm-project/compiler-rt
3. Patch src/llvm-project/compiler-rt/lib/builtins/int_types.h to remove #define CRT_HAS_128BIT.
4. Copy riscv32imac-unknown-xous-elf.json to your Rust sysroot under a new target directory. This can be done on Unix-like systems by running:

mkdir -p $(rustc --print sysroot)/lib/rustlib/riscv32imac-unknown-xous-elf/lib
cp riscv32imac-unknown-xous-elf.json $(rustc --print sysroot)/lib/rustlib/riscv32imac-unknown-xous-elf/target.json

5. Compile the standard library:

CARGO_PROFILE_RELEASE_DEBUG=0 \
CARGO_PROFILE_RELEASE_DEBUG_ASSERTIONS=false \
RUSTC_BOOTSTRAP=1 \
__CARGO_DEFAULT_LIB_METADATA=stablestd \
cargo build \
    --target riscv32imac-unknown-xous-elf \
    -Zbinary-dep-depinfo \
    --release \
    --features "panic-unwind backtrace compiler-builtins-c compiler-builtins-mem" \
    --manifest-path "library/sysroot/Cargo.toml"

6. Install the standard library to your new sysroot:

mkdir -p $(rustc --print sysroot)/lib/rustlib/riscv32imac-unknown-xous-elf/lib/
cp target/riscv32imac-unknown-xous-elf/release/deps/*.rlib $(rustc --print sysroot)/lib/rustlib/riscv32imac-unknown-xous-elf/lib/

7. Use the new stdlib by setting --target:

cargo build --target riscv32imac-unknown-xous-elf

Building on Windows Powershell

On Windows, you can use the rebuild.ps1 script to build and install this package. You will need to have a Riscv compiler in your path.

Run rebuild.ps1. It is recommended that you run it under a new shell in order to avoid polluting your environment with Rust-specific variables:

powershell .\rebuild.ps1

Alternately, you can run the following commands to manually build things:

$env:RUST_TARGET_PATH=$(rustc --print sysroot)
Copy-Item riscv32imac-unknown-xous-elf.json $env:RUST_TARGET_PATH
$env:CARGO_PROFILE_RELEASE_DEBUG=0
$env:CARGO_PROFILE_RELEASE_DEBUG_ASSERTIONS="false"
$env:RUSTC_BOOTSTRAP=1
$env:__CARGO_DEFAULT_LIB_METADATA="stablestd"
Remove-Item .\target\riscv32imac-unknown-xous-elf\release\deps\*.rlib
cargo build `
    --target riscv32imac-unknown-xous-elf `
    -Zbinary-dep-depinfo `
    --release `
    --features "panic-unwind backtrace compiler-builtins-c compiler-builtins-mem" `
    --manifest-path "library/sysroot/Cargo.toml"
New-Item -Type Directory -Path "$env:RUST_TARGET_PATH\lib\rustlib\riscv32imac-unknown-xous-elf\lib"
Remove-Item "$env:RUST_TARGET_PATH\lib\rustlib\riscv32imac-unknown-xous-elf\lib\*.rlib"
Copy-Item target\riscv32imac-unknown-xous-elf\release\deps\*.rlib "$env:RUST_TARGET_PATH\lib\rustlib\riscv32imac-unknown-xous-elf\lib"