Rename method in opt-dist

This makes it clearer that the LLVM is the host one (it doesn't necessarily have to be downloaded).

src/tools/opt-dist/src/environment/linux.rs

@@ -14,7 +14,7 @@ fn checkout_path(&self) -> Utf8PathBuf {
         Utf8PathBuf::from("/checkout")
     }
 
-    fn downloaded_llvm_dir(&self) -> Utf8PathBuf {
+    fn host_llvm_dir(&self) -> Utf8PathBuf {
         Utf8PathBuf::from("/rustroot")
     }
 

src/tools/opt-dist/src/environment/mod.rs

@@ -15,8 +15,8 @@ fn host_triple(&self) -> String {
     /// The rustc checkout, where the compiler source is located.
     fn checkout_path(&self) -> Utf8PathBuf;
 
-    /// Path to the downloaded host LLVM.
-    fn downloaded_llvm_dir(&self) -> Utf8PathBuf;
+    /// Path to the host LLVM used to compile LLVM in `src/llvm-project`.
+    fn host_llvm_dir(&self) -> Utf8PathBuf;
 
     /// Directory where the optimization artifacts (PGO/BOLT profiles, etc.)
     /// will be stored.

src/tools/opt-dist/src/environment/windows.rs

@@ -24,7 +24,7 @@ fn checkout_path(&self) -> Utf8PathBuf {
         self.checkout_dir.clone()
     }
 
-    fn downloaded_llvm_dir(&self) -> Utf8PathBuf {
+    fn host_llvm_dir(&self) -> Utf8PathBuf {
         self.checkout_path().join("citools").join("clang-rust")
     }
 

src/tools/opt-dist/src/training.rs

@@ -81,7 +81,7 @@ fn merge_llvm_profiles(
     profdata: LlvmProfdata,
 ) -> anyhow::Result<()> {
     let llvm_profdata = match profdata {
-        LlvmProfdata::Host => env.downloaded_llvm_dir().join("bin/llvm-profdata"),
+        LlvmProfdata::Host => env.host_llvm_dir().join("bin/llvm-profdata"),
         LlvmProfdata::Target => env
             .build_artifacts()
             .join("llvm")