Merge pull request #26 from wez/cross

Support cross compilation

Author: khvzak

.github/workflows/main.yml

@@ -72,6 +72,47 @@ jobs:
         TRYBUILD=overwrite cargo test --release --features "${{ matrix.lua }} vendored async send serialize" -- --ignored
       shell: bash
 
+  test_arm_cross_macos:
+    name: Test Cross compilation for ARM from Intel on macOS
+    runs-on: macos-11.0
+    strategy:
+      matrix:
+        lua: [lua54, lua53, lua52, lua51]
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions-rs/toolchain@v1
+      with:
+        toolchain: nightly
+        target: x86_64-apple-darwin
+        override: true
+    - name: Add ARM target
+      run: rustup target add aarch64-apple-darwin
+    - name: Cross compile
+      run: cargo build --target aarch64-apple-darwin --features "${{ matrix.lua }} async send serialize vendored"
+
+  test_arm_cross_ubuntu:
+    name: Test cross compilation for ARM from Intel on Linux
+    runs-on: ubuntu-18.04
+    strategy:
+      matrix:
+        lua: [lua54, lua53, lua52, lua51]
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions-rs/toolchain@v1
+      with:
+        toolchain: nightly
+        target: x86_64-unknown-linux-gnu
+        override: true
+    - name: Add ARM target
+      run: rustup target add armv7-unknown-linux-gnueabihf
+    - name: Install ARM compiler toolchain
+      run: |
+        sudo apt-get update -y
+        sudo apt-get install -y --no-install-recommends gcc-arm-linux-gnueabihf libc-dev-armhf-cross
+    - name: Cross compile
+      run: cargo build --target armv7-unknown-linux-gnueabihf --features "${{ matrix.lua }} async send serialize vendored"
+      shell: bash
+
   test_luajit_macos:
     name: Test LuaJIT on macOS
     runs-on: macos-latest

build/main.rs

@@ -91,6 +91,129 @@ fn build_glue<P: AsRef<Path> + std::fmt::Debug>(include_path: &P) {
         .unwrap();
 }
 
+// When cross-compiling, we cannot use `build_glue` as we cannot run the generated
+// executable.  Instead, let's take a stab at synthesizing the likely values.
+// If you're cross-compiling and using a non-vendored library then there is a chance
+// that the values selected here may be incorrect, but we have no way to determine
+// that here.
+fn generate_glue() -> std::io::Result<()> {
+    use std::io::Write;
+    let build_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    let mut glue = std::fs::File::create(build_dir.join("glue.rs"))?;
+    write!(
+        glue,
+        "/* This file was generated by build/main.rs; do not modify by hand */\n"
+    )?;
+    write!(glue, "use std::os::raw::*;\n")?;
+
+    // We can't statically determine the default paths.
+    // It is possible though to use something like lazy_static! to create a new
+    // lua context and extract that information.
+    // For my (@wez) purposes, I actually don't want there to be a default path,
+    // so I'm just leaving this blank for the moment.
+    write!(glue, "pub const LUA_PATH_DEFAULT: &str = \"\";\n")?;
+    write!(glue, "pub const LUA_CPATH_DEFAULT: &str = \"\";\n")?;
+
+    write!(
+        glue,
+        "#[cfg(windows)] pub const LUA_DIRSEP: &str = \"\\\\\";\n"
+    )?;
+    write!(glue, "#[cfg(unix)] pub const LUA_DIRSEP: &str = \"/\";\n")?;
+
+    let pointer_bit_width: usize = env::var("CARGO_CFG_TARGET_POINTER_WIDTH")
+        .unwrap()
+        .parse()
+        .unwrap();
+    write!(
+        glue,
+        "pub const LUA_EXTRASPACE: c_int = {} / 8;\n",
+        pointer_bit_width
+    )?;
+
+    // This is generally hardcoded to this size
+    write!(glue, "pub const LUA_IDSIZE: c_int = 60;\n")?;
+
+    write!(glue, "pub const LUAL_BUFFERSIZE: c_int = 16 * ({} / 8) * std::mem::size_of::<LUA_NUMBER>() as c_int;\n", pointer_bit_width)?;
+
+    // Unless the target is restricted, the defaults are 64 bit
+    write!(glue, "pub type LUA_NUMBER = c_double;\n")?;
+    write!(glue, "pub type LUA_INTEGER = i64;\n")?;
+    write!(glue, "pub type LUA_UNSIGNED = u64;\n")?;
+
+    let version = if cfg!(feature = "luajit") || cfg!(feature = "lua51") {
+        (5, 1, 0)
+    } else if cfg!(feature = "lua52") {
+        (5, 2, 0)
+    } else if cfg!(feature = "lua53") {
+        (5, 3, 0)
+    } else if cfg!(feature = "lua54") {
+        (5, 4, 0)
+    } else {
+        unreachable!();
+    };
+
+    write!(
+        glue,
+        "pub const LUA_VERSION_NUM: c_int = {};\n",
+        (version.0 * 100) + version.1
+    )?;
+    write!(
+        glue,
+        "pub const LUA_VERSION: &str = \"Lua {}.{}\";\n",
+        version.0, version.1
+    )?;
+    write!(
+        glue,
+        "pub const LUA_RELEASE: &str = \"Lua {}.{}.{}\";\n",
+        version.0, version.1, version.2
+    )?;
+
+    let max_stack = if pointer_bit_width >= 32 {
+        1_000_000
+    } else {
+        15_000
+    };
+    write!(
+        glue,
+        "pub const LUA_REGISTRYINDEX: c_int = -{} - 1000;\n",
+        max_stack
+    )?;
+
+    // These two are only defined in lua 5.1
+    write!(glue, "pub const LUA_ENVIRONINDEX: c_int = -10001;\n")?;
+    write!(glue, "pub const LUA_GLOBALSINDEX: c_int = -10002;\n")?;
+
+    // This is only defined in lua 5.3 and up, but we can always generate its value here,
+    // even if we don't use it.
+    // This matches the default definition in lauxlib.h
+    write!(glue, "pub const LUAL_NUMSIZES: c_int = std::mem::size_of::<LUA_INTEGER>() as c_int * 16 + std::mem::size_of::<LUA_NUMBER>() as c_int;\n")?;
+
+    write!(
+        glue,
+        r#"
+#[cfg(feature = "luajit")]
+pub const LUA_BITLIBNAME: &str = "bit";
+#[cfg(not(feature = "luajit"))]
+pub const LUA_BITLIBNAME: &str = "bit32";
+
+pub const LUA_COLIBNAME: &str = "coroutine";
+pub const LUA_DBLIBNAME: &str = "debug";
+pub const LUA_IOLIBNAME: &str = "io";
+pub const LUA_LOADLIBNAME: &str = "package";
+pub const LUA_MATHLIBNAME: &str = "math";
+pub const LUA_OSLIBNAME: &str = "os";
+pub const LUA_STRLIBNAME: &str = "string";
+pub const LUA_TABLIBNAME: &str = "table";
+pub const LUA_UTF8LIBNAME: &str = "utf8";
+
+pub const LUA_JITLIBNAME: &str = "jit";
+pub const LUA_FFILIBNAME: &str = "ffi";
+"#
+    )?;
+
+    Ok(())
+}
+
 fn main() {
     #[cfg(not(any(
         feature = "lua54",
@@ -132,5 +255,9 @@ fn main() {
     );
 
     let include_dir = find::probe_lua();
-    build_glue(&include_dir);
+    if env::var("TARGET").unwrap() != env::var("HOST").unwrap() {
+        generate_glue().unwrap();
+    } else {
+        build_glue(&include_dir);
+    }
 }