Add llvm_components_contain to run-make-support

src/tools/run-make-support/src/lib.rs

@@ -61,7 +61,7 @@ pub mod rfs {
 pub use run::{cmd, run, run_fail, run_with_args};
 
 /// Helpers for checking target information.
-pub use targets::{is_darwin, is_msvc, is_windows, target, uname};
+pub use targets::{is_darwin, is_msvc, is_windows, llvm_components_contain, target, uname};
 
 /// Helpers for building names of output artifacts that are potentially target-specific.
 pub use artifact_names::{

src/tools/run-make-support/src/targets.rs

@@ -28,6 +28,13 @@ pub fn is_darwin() -> bool {
     target().contains("darwin")
 }
 
+/// Check if `component` is within `LLVM_COMPONENTS`
+#[must_use]
+pub fn llvm_components_contain(component: &str) -> bool {
+    // `LLVM_COMPONENTS` is a space-separated list of words
+    env_var("LLVM_COMPONENTS").split_whitespace().find(|s| s == &component).is_some()
+}
+
 /// Run `uname`. This assumes that `uname` is available on the platform!
 #[track_caller]
 #[must_use]