add options to allow generating statically linked binaries

Signed-off-by: Jorge Prendes <[email protected]>

crates/wasmedge-sys/build.rs

@@ -7,6 +7,8 @@ use build_paths::{Env, LibWasmEdgePaths};
 mod build_standalone;
 use build_standalone::*;
 
+use crate::build_paths::AsPath;
+
 const WASMEDGE_RELEASE_VERSION: &str = "0.13.3";
 const REMOTE_ARCHIVES: phf::Map<&'static str, (&'static str, &'static str)> = phf_map! {
     "macos/aarch64"         => ("db03037e2678e197f9cd5f01392ee088df07e7726849626190f2d4ec1dc693c9", "darwin_arm64"),
@@ -87,11 +89,9 @@ fn main() {
         // Tell cargo to tell rustc to link our `wasmedge` library. Cargo will
         // automatically know it must look for a `libwasmedge.a` file.
         println!("cargo:rustc-link-lib=static=wasmedge");
-        println!("cargo:rustc-link-lib=rt");
-        println!("cargo:rustc-link-lib=dl");
-        println!("cargo:rustc-link-lib=pthread");
-        println!("cargo:rustc-link-lib=m");
-        println!("cargo:rustc-link-lib=stdc++");
+        for dep in ["rt", "dl", "pthread", "m", "stdc++"] {
+            link_lib(dep);
+        }
     } else {
         println!("cargo:rustc-env=LD_LIBRARY_PATH={lib_dir}");
         println!("cargo:rustc-link-search={lib_dir}");
@@ -107,16 +107,55 @@ fn main() {
     let out_file = OUT_DIR.join("wasmedge.rs");
 
     debug!("generating bindgen header {out_file:?}");
-    bindgen::builder()
-        .header(header)
-        .clang_arg(format!("-I{inc_dir}"))
-        .prepend_enum_name(false) // The API already prepends the name.
-        .dynamic_link_require_all(true)
-        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
-        .generate()
-        .expect("failed to generate bindings")
-        .write_to_file(out_file)
-        .expect("failed to write bindings");
+    if let Some(bindgen_path) = Env("WASMEDGE_RUST_BINDGEN_PATH").as_path() {
+        let success = std::process::Command::new(bindgen_path)
+            .arg("--no-prepend-enum-name") // The API already prepends the name.
+            .arg("--dynamic-link-require-all")
+            .arg("--formatter=none")
+            .arg("-o")
+            .arg(out_file)
+            .arg(header)
+            .arg("--")
+            .arg(format!("-I{inc_dir}"))
+            .status()
+            .expect("failed to run rust bindgen")
+            .success();
+        assert!(success, "failed to run rust bindgen");
+    } else {
+        bindgen::builder()
+            .header(header)
+            .clang_arg(format!("-I{inc_dir}"))
+            .prepend_enum_name(false) // The API already prepends the name.
+            .dynamic_link_require_all(true)
+            .parse_callbacks(Box::new(bindgen::CargoCallbacks))
+            .generate()
+            .expect("failed to generate bindings")
+            .write_to_file(out_file)
+            .expect("failed to write bindings");
+    }
+}
+
+fn link_lib(dep: &str) {
+    // Sanitize dependency name for evn-vars, particularly `stdc++`.
+    let dep_slug: String = dep.replace('+', "x").to_uppercase();
+
+    let generic_link_type_var = Env!("WASMEDGE_DEPS_LINK_TYPE");
+    let generic_lib_path_var = Env!("WASMEDGE_DEPS_LIB_PATH");
+    let named_link_type_var = Env!("WASMEDGE_DEP_{dep_slug}_LINK_TYPE");
+    let named_lib_path_var = Env!("WASMEDGE_DEP_{dep_slug}_LIB_PATH");
+
+    let link_type = named_link_type_var
+        .lossy()
+        .or_else(|| generic_link_type_var.lossy())
+        .unwrap_or("dylib".to_string());
+
+    for path_var in [named_lib_path_var, generic_lib_path_var] {
+        if let Some(path) = path_var.lossy() {
+            println!("cargo:rustc-link-search={path}");
+        }
+    }
+
+    println!("cargo:rustc-link-lib={link_type}={dep}");
 }
 
 #[macro_export]
@@ -125,3 +164,8 @@ macro_rules! debug {
         println!("cargo:warning=[wasmedge-sys] {}", format!($($args),+))
     };
 }
+
+#[macro_export]
+macro_rules! Env {
+    ($($args:expr),+) => { Env(format!($($args),+)) };
+}

crates/wasmedge-sys/build_paths.rs

@@ -1,10 +1,13 @@
 use crate::debug;
 
-pub struct Env<'a>(pub &'a str);
+pub struct Env<S: AsRef<str>>(pub S);
 
-impl Env<'_> {
+impl<S: AsRef<str>> Env<S> {
     pub fn read<T: From<std::ffi::OsString>>(&self) -> Option<T> {
-        std::env::var_os(self.0).map(T::from)
+        if self.0.as_ref() != "OUT_DIR" && !self.0.as_ref().starts_with("CARGO_") {
+            println!("cargo:rerun-if-env-changed={}", self.0.as_ref());
+        }
+        std::env::var_os(self.0.as_ref()).map(T::from)
     }
 
     pub fn expect<T: TryFrom<std::ffi::OsString>>(&self, msg: &str) -> T
@@ -31,9 +34,8 @@ pub trait AsPath {
     fn as_path(&self) -> Option<std::path::PathBuf>;
 }
 
-impl AsPath for Env<'_> {
+impl<S: AsRef<str>> AsPath for Env<S> {
     fn as_path(&self) -> Option<std::path::PathBuf> {
-        println!("cargo:rerun-if-env-changed={}", self.0);
         self.read()
     }
 }

crates/wasmedge-sys/build_standalone.rs

@@ -108,7 +108,7 @@ fn get_remote_archive() -> Archive {
 
 fn do_http_request(url: &str) -> impl std::io::Read {
     let builder = reqwest::blocking::Client::builder();
-    let builder = match Env("STANDALONE_PROXY").lossy() {
+    let builder = match Env("WASMEDGE_STANDALONE_PROXY").lossy() {
         Some(proxy) => {
             debug!("using proxy to download archive: {proxy}");
             let proxy = reqwest::Proxy::all(proxy).expect("failed to parse proxy");