1 files changed, 23 insertions, 3 deletions
diff --git a/src/bootstrap/util.rs b/src/bootstrap/util.rs
index 0ebabbd5c..582207832 100644
--- a/src/bootstrap/util.rs
+++ b/src/bootstrap/util.rs
@@ -13,6 +13,7 @@ use std::time::{Instant, SystemTime, UNIX_EPOCH};
 
 use crate::builder::Builder;
 use crate::config::{Config, TargetSelection};
+use crate::OnceCell;
 
 /// A helper macro to `unwrap` a result except also print out details like:
 ///
@@ -43,7 +44,13 @@ pub use t;
 /// Given an executable called `name`, return the filename for the
 /// executable for a particular target.
 pub fn exe(name: &str, target: TargetSelection) -> String {
-    if target.contains("windows") { format!("{}.exe", name) } else { name.to_string() }
+    if target.contains("windows") {
+        format!("{}.exe", name)
+    } else if target.contains("uefi") {
+        format!("{}.efi", name)
+    } else {
+        name.to_string()
+    }
 }
 
 /// Returns `true` if the file name given looks like a dynamic library.
@@ -104,7 +111,7 @@ pub struct TimeIt(bool, Instant);
 
 /// Returns an RAII structure that prints out how long it took to drop.
 pub fn timeit(builder: &Builder<'_>) -> TimeIt {
-    TimeIt(builder.config.dry_run, Instant::now())
+    TimeIt(builder.config.dry_run(), Instant::now())
 }
 
 impl Drop for TimeIt {
@@ -127,7 +134,7 @@ pub(crate) fn program_out_of_date(stamp: &Path, key: &str) -> bool {
 /// Symlinks two directories, using junctions on Windows and normal symlinks on
 /// Unix.
 pub fn symlink_dir(config: &Config, src: &Path, dest: &Path) -> io::Result<()> {
-    if config.dry_run {
+    if config.dry_run() {
         return Ok(());
     }
     let _ = fs::remove_dir(dest);
@@ -607,3 +614,16 @@ pub fn get_clang_cl_resource_dir(clang_cl_path: &str) -> PathBuf {
     let clang_rt_dir = clang_rt_builtins.parent().expect("The clang lib folder should exist");
     clang_rt_dir.to_path_buf()
 }
+
+pub fn lld_flag_no_threads(is_windows: bool) -> &'static str {
+    static LLD_NO_THREADS: OnceCell<(&'static str, &'static str)> = OnceCell::new();
+    let (windows, other) = LLD_NO_THREADS.get_or_init(|| {
+        let out = output(Command::new("lld").arg("-flavor").arg("ld").arg("--version"));
+        let newer = match (out.find(char::is_numeric), out.find('.')) {
+            (Some(b), Some(e)) => out.as_str()[b..e].parse::<i32>().ok().unwrap_or(14) > 10,
+            _ => true,
+        };
+        if newer { ("/threads:1", "--threads=1") } else { ("/no-threads", "--no-threads") }
+    });
+    if is_windows { windows } else { other }
+}