let wasm_runtime build its own toolchain

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

Author: jprendes

src/hyperlight_wasm/build.rs

@@ -106,34 +106,13 @@ fn build_wasm_runtime() -> PathBuf {
     println!("cargo::rerun-if-env-changed=WIT_WORLD");
     // the PROFILE env var unfortunately only gives us 1 bit of "dev or release"
     let cargo_profile = if profile == "debug" { "dev" } else { "release" };
-    let mut cargo_cmd = std::process::Command::new(&cargo_bin);
 
     // Clear the variables that control Cargo's behaviour (as listed
     // at https://doc.rust-lang.org/cargo/reference/environment-variables.html):
     // otherwise the nested build will build the wrong thing
     let mut env_vars = env::vars().collect::<Vec<_>>();
     env_vars.retain(|(key, _)| !key.starts_with("CARGO_"));
 
-    // we need to build hyperlight-guest-bin dependency of wasm_runtime, before wasm_runtime
-    let cmd = cargo_cmd
-        .arg("build")
-        .arg("--profile")
-        .arg(cargo_profile)
-        .arg("--package")
-        .arg("hyperlight-guest-bin")
-        .arg("-v")
-        .arg("--target-dir")
-        .arg(&target_dir)
-        .current_dir(&in_repo_dir)
-        .env_clear()
-        .envs(env_vars.clone());
-    let status = cmd
-        .status()
-        .unwrap_or_else(|e| panic!("could not run cargo build hyperlight-guest-bin: {}", e));
-    if !status.success() {
-        panic!("could not compile wasm_runtime");
-    }
-
     let mut cargo_cmd = std::process::Command::new(&cargo_bin);
     let cmd = cargo_cmd
         .arg("build")

src/wasm_runtime/.cargo/config.toml

@@ -10,9 +10,6 @@ rustflags = [
 ]
 linker = "rust-lld"
 
-[env]
-HYPERLIGHT_GUEST_TOOLCHAIN_ROOT = { value = "guest-toolchain", relative = true }
-
 [profile.release]
 panic = "abort"
 

src/wasm_runtime/build.rs

@@ -14,21 +14,73 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-use std::path::Path;
-use std::{env, fs, path};
+use std::path::{Path, PathBuf};
+use std::{env, fs};
 
 use cargo_metadata::{MetadataCommand, Package};
 
+fn ensure_toolchain() -> PathBuf {
+    let out_dir = env::var("OUT_DIR").unwrap();
+    let out_dir = PathBuf::from(out_dir);
+    let toolchain_dir = env::var("HYPERLIGHT_GUEST_TOOLCHAIN_ROOT")
+        .map(PathBuf::from)
+        .unwrap_or_else(|_| out_dir.join("toolchain"));
+
+    if toolchain_dir.join("clang").exists() {
+        return toolchain_dir;
+    }
+
+    let cargo_bin = env::var_os("CARGO").unwrap();
+    let mut cargo_cmd = std::process::Command::new(&cargo_bin);
+
+    let profile = env::var_os("PROFILE").unwrap();
+    let profile = if profile == "debug" { "dev" } else { "release" };
+
+    // Clear the variables that control Cargo's behaviour (as listed
+    // at https://doc.rust-lang.org/cargo/reference/environment-variables.html):
+    // otherwise the nested build will build the wrong thing
+    let mut env_vars = env::vars().collect::<Vec<_>>();
+    env_vars.retain(|(key, _)| !key.starts_with("CARGO_"));
+
+    // we need to build hyperlight-guest-bin dependency of wasm_runtime, before wasm_runtime
+    let cmd = cargo_cmd
+        .arg("build")
+        .arg("--profile")
+        .arg(profile)
+        .arg("--package")
+        .arg("hyperlight-guest-bin")
+        .arg("-v")
+        .arg("--target-dir")
+        .arg(out_dir.join("toolchain-build"))
+        .env_clear()
+        .envs(env_vars)
+        .env("HYPERLIGHT_GUEST_TOOLCHAIN_ROOT", &toolchain_dir);
+
+    let status = cmd
+        .status()
+        .unwrap_or_else(|e| panic!("could not run build hyperlight toolchain: {}", e));
+
+    if !status.success() {
+        panic!("could not compile wasm_runtime");
+    }
+
+    assert!(
+        toolchain_dir.join("clang").exists(),
+        "could not find toolchain at {toolchain_dir:?} after building hyperlight-guest-bin",
+    );
+
+    toolchain_dir
+}
+
 fn main() {
+    let toolchain_dir = ensure_toolchain();
+
     println!("cargo:rerun-if-changed=.");
     let mut cfg = cc::Build::new();
-    if let Some(path) = env::var_os("PATH") {
-        let paths: Vec<_> = env::split_paths(&path).collect();
-        let toolchain_path =
-            path::PathBuf::from(env::var_os("HYPERLIGHT_GUEST_TOOLCHAIN_ROOT").unwrap());
-        let joined = env::join_paths(std::iter::once(toolchain_path).chain(paths)).unwrap();
-        env::set_var("PATH", &joined);
-    }
+    let path = env::var_os("PATH").unwrap_or_default();
+    let paths = env::split_paths(&path);
+    let joined = env::join_paths(paths.chain(std::iter::once(toolchain_dir))).unwrap();
+    env::set_var("PATH", &joined);
 
     // Get the wasmtime_platform.h file from the appropriate wasm release