Make run-make work with other codegen backend than LLVM

Author: GuillaumeGomez

src/tools/compiletest/src/runtest/run_make.rs

@@ -201,7 +201,9 @@ impl TestCx<'_> {
             .env("RUSTC", &self.config.rustc_path)
             // Provide which LLVM components are available (e.g. which LLVM components are provided
             // through a specific CI runner).
-            .env("LLVM_COMPONENTS", &self.config.llvm_components);
+            .env("LLVM_COMPONENTS", &self.config.llvm_components)
+            // In case it's a different codegen backend than LLVM.
+            .env("RUSTC_CODEGEN_BACKEND", self.config.default_codegen_backend.as_str());
 
         // The `run-make-cargo` and `build-std` suites need an in-tree `cargo`, `run-make` does not.
         if matches!(self.config.suite, TestSuite::RunMakeCargo | TestSuite::BuildStd) {

src/tools/run-make-support/src/external_deps/rustc.rs

@@ -76,6 +76,10 @@ pub fn rustc_path() -> String {
 fn setup_common() -> Command {
     let mut cmd = Command::new(rustc_path());
     set_host_compiler_dylib_path(&mut cmd);
+    eprintln!("-----> {:?}", std::env::var("RUSTC_CODEGEN_BACKEND"));
+    if let Ok(codegen_backend) = std::env::var("RUSTC_CODEGEN_BACKEND") {
+        cmd.arg(format!("-Zcodegen-backend={codegen_backend}"));
+    }
     cmd
 }