Do not invoke external lld to figure out thread flags in self-contained mode

Author: Kobzol

src/bootstrap/src/utils/helpers.rs

@@ -443,17 +443,29 @@ pub fn get_clang_cl_resource_dir(clang_cl_path: &str) -> PathBuf {
  clang_rt_dir.to_path_buf()
 }
 
-pubfnlld_flag_no_threads(is_windows:bool) -> &'staticstr{
+/// Returns a flag that configures LLD to use only a single thread.
+/// If we use an external LLD, we need to find out which version is it to know which flag should we
+/// pass to it (LLD older than version 10 had a different flag).
+fnlld_flag_no_threads(lld_mode:LldMode,is_windows:bool) -> &'staticstr{
 staticLLD_NO_THREADS:OnceLock<(&'staticstr,&'staticstr)> = OnceLock::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,
+
+let new_flags = ("/threads:1","--threads=1");
+let old_flags = ("/no-threads","--no-threads");
+
+let(windows_flag, other_flag) = LLD_NO_THREADS.get_or_init(|| {
+let newer_version = match lld_mode {
+LldMode::External => {
+let out = output(Command::new("lld").arg("-flavor").arg("ld").arg("--version"));
+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,
+}
+}
  _ => true,
 };
-ifnewer{("/threads:1","--threads=1")}else{("/no-threads","--no-threads")}
+ifnewer_version{new_flags }else{old_flags}
 });
-if is_windows {windows}else{other}
+if is_windows {windows_flag}else{other_flag}
 }
 
 pubfndir_is_empty(dir:&Path) -> bool{
@@ -512,7 +524,10 @@ pub fn linker_flags(
 }
 
 ifmatches!(lld_threads,LldThreads::No){
- args.push(format!("-Clink-arg=-Wl,{}", lld_flag_no_threads(target.is_msvc())));
+ args.push(format!(
+"-Clink-arg=-Wl,{}",
+ lld_flag_no_threads(builder.config.lld_mode.clone(), target.is_msvc())
+));
 }
 }
  args