Cross-Compilation

CIS 198 Lecture 18

Rustup (beta)

  • Successor to Multirust.

    • Currently in beta (try it out! - but not until after your projects.)
    • Written in Rust, not shell - works natively on Windows!

  • Still allows you to easily maintain multiple toolchains.

    • e.g. stable, beta, nightly-2016-04-15, 1.8.0

  • Supports cross-compilation nicely!

    • Can download cross-compilation targets & std for other targets.
    • rustup target list - OS X, iOS, Windows, Android, etc.
    • rustup target add x86_64-pc-windows-gnu

  • Can still override the toolchain for a particular project:

    • rustup override add nightly - overrides current directory
    • rustup override list - lists overrides

  • Run commands with a particular toolchain:

    • rustup run nightly COMMAND

Linux to Windows

  • Minimal demo

    • Requires MinGW-w64.

  • Add the 64-bit Windows target:

    • rustup target add x86_64-pc-windows-gnu

  • Configure Cargo to target Windows and link using the MinGW-w64 linker.

    • .cargo/config:

      1.   [target.x86_64-pc-windows-gnu]
      2.   linker = "/usr/bin/x86_64-w64-mingw32-gcc"
      3.   ar = "/usr/x86_64-w64-mingw32-ar"
      5.   [build]
      6.   target = "x86_64-pc-windows-gnu"
    • In the future, this may be handled by:
      • rustup override add stable-x86_64-pc-windows-gnu
        1. - (Currently doesn't quite work for me.)

Linux to Windows

  • cargo build! Build appears at:

    • target/x86_64-pc-windows-gnu/debug/xcompile-win.exe
    • PE32+ executable (console) x86-64, for MS Windows

  • Executable can be run on Windows (or under Wine).

    • Demo

Linux to Android

  • Minimal demo

  • Rustup has a target for this: arm-linux-androideabi

    • But this will only get us a bare binary - not an APK.
    • ELF 32-bit LSB relocatable, ARM, EABI5 version 1 (SYSV)

  • For APKs, we can use cargo-apk (announcement).

    • Compiles Rust code to a shared object (.so) file
    • Uses android-rs-glue.
      • Simple Java template for loading a shared object (.so) file and dynamically links it from Java.
    • Builds using Android build tools.
    • Host must be Linux x86_64 (currently).

Linux to Android

  • cargo install cargo-apk

  • Cargo.toml:

    1.   [package.metadata.android]
    2.   label = "xcompile-198"
    4.   [dependencies]
    5.   android_glue = "0.1.3"

  • Build and install:

    1.   export ANDROID_SDK_HOME=/opt/android-sdk
    2.   export NDK_HOME=/opt/android-ndk
    3.   cargo apk install
    • Demo