bootstrap: skip llvm-tools install when externally provided

src/bootstrap/compile.rs

@@ -872,7 +872,7 @@ pub fn rustc_cargo_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetS
         && (builder.kind != Kind::Check
             || crate::native::prebuilt_llvm_config(builder, target).is_ok())
     {
-        if builder.is_rust_llvm(target) {
+        if builder.config.is_rust_llvm(target) {
             cargo.env("LLVM_RUSTLLVM", "1");
         }
         let native::LlvmResult { llvm_config, .. } = builder.ensure(native::Llvm { target });

src/bootstrap/config.rs

@@ -1606,6 +1606,21 @@ impl Config {
             })
     }
 
+    /// Returns `true` if no custom `llvm-config` is set for the specified target.
+    ///
+    /// If no custom `llvm-config` was specified then Rust's llvm will be used.
+    pub fn is_rust_llvm(&self, target: TargetSelection) -> bool {
+        match self.target_config.get(&target) {
+            Some(Target { llvm_has_rust_patches: Some(patched), .. }) => *patched,
+            Some(Target { llvm_config, .. }) => {
+                // If the user set llvm-config we assume Rust is not patched,
+                // but first check to see if it was configured by llvm-from-ci.
+                (self.llvm_from_ci && target == self.build) || llvm_config.is_none()
+            }
+            None => true,
+        }
+    }
+
     pub fn submodules(&self, rust_info: &GitInfo) -> bool {
         self.submodules.unwrap_or(rust_info.is_managed_git_subrepository())
     }

src/bootstrap/install.rs

@@ -209,7 +209,7 @@ install!((self, builder, _config),
             );
         }
     };
-    LlvmTools, alias = "llvm-tools", Self::should_build(_config), only_hosts: true, {
+    LlvmTools, alias = "llvm-tools", should_build_llvm(_config), only_hosts: true, {
         let tarball = builder
             .ensure(dist::LlvmTools { target: self.target })
             .expect("missing llvm-tools");
@@ -251,6 +251,11 @@ install!((self, builder, _config),
     };
 );
 
+fn should_build_llvm(config: &Config) -> bool {
+    // additionaly check that llvm is not externally provided
+    LlvmTools::should_build(config) && config.is_rust_llvm(config.build)
+}
+
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct Src {
     pub stage: u32,

src/bootstrap/lib.rs

@@ -28,7 +28,7 @@ use std::str;
 
 use build_helper::ci::CiEnv;
 use channel::GitInfo;
-use config::{DryRun, Target};
+use config::DryRun;
 use filetime::FileTime;
 use once_cell::sync::OnceCell;
 
@@ -831,21 +831,6 @@ impl Build {
         INTERNER.intern_path(self.out.join(&*target.triple).join("md-doc"))
     }
 
-    /// Returns `true` if no custom `llvm-config` is set for the specified target.
-    ///
-    /// If no custom `llvm-config` was specified then Rust's llvm will be used.
-    fn is_rust_llvm(&self, target: TargetSelection) -> bool {
-        match self.config.target_config.get(&target) {
-            Some(Target { llvm_has_rust_patches: Some(patched), .. }) => *patched,
-            Some(Target { llvm_config, .. }) => {
-                // If the user set llvm-config we assume Rust is not patched,
-                // but first check to see if it was configured by llvm-from-ci.
-                (self.config.llvm_from_ci && target == self.config.build) || llvm_config.is_none()
-            }
-            None => true,
-        }
-    }
-
     /// Returns the path to `FileCheck` binary for the specified target
     fn llvm_filecheck(&self, target: TargetSelection) -> PathBuf {
         let target_config = self.config.target_config.get(&target);

src/bootstrap/test.rs

@@ -1635,7 +1635,7 @@ note: if you're sure you want to do this, please open an issue as to why. In the
                     .arg(llvm_components.trim());
                 llvm_components_passed = true;
             }
-            if !builder.is_rust_llvm(target) {
+            if !builder.config.is_rust_llvm(target) {
                 cmd.arg("--system-llvm");
             }