Rollup merge of #88751 - bjorn3:move_filesearch, r=oli-obk

Couple of changes to FileSearch and SearchPath

* Turn a couple of regular comments into doc comments
* Move `get_tools_search_paths` from `FileSearch` to `Session`
* Use Lrc instead of Option to avoid duplication of a `SearchPath`

1 files changed, 21 insertions, 9 deletions

diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 4471e1e0ae8..d6f4a3ae4f1 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -36,7 +36,7 @@ use std::fmt;
 use std::io::Write;
 use std::num::NonZeroU32;
 use std::ops::{Div, Mul};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::sync::Arc;
 use std::time::Duration;
@@ -131,9 +131,8 @@ pub struct Session {
     pub target: Target,
     pub host: Target,
     pub opts: config::Options,
-    pub host_tlib_path: SearchPath,
-    /// `None` if the host and target are the same.
-    pub target_tlib_path: Option<SearchPath>,
+    pub host_tlib_path: Lrc<SearchPath>,
+    pub target_tlib_path: Lrc<SearchPath>,
     pub parse_sess: ParseSess,
     pub sysroot: PathBuf,
     /// The name of the root source file of the crate, in the local file system.
@@ -787,8 +786,7 @@ impl Session {
             &self.sysroot,
             self.opts.target_triple.triple(),
             &self.opts.search_paths,
-            // `target_tlib_path == None` means it's the same as `host_tlib_path`.
-            self.target_tlib_path.as_ref().unwrap_or(&self.host_tlib_path),
+            &self.target_tlib_path,
             kind,
         )
     }
@@ -802,6 +800,18 @@ impl Session {
         )
     }
 
+    /// Returns a list of directories where target-specific tool binaries are located.
+    pub fn get_tools_search_paths(&self, self_contained: bool) -> Vec<PathBuf> {
+        let rustlib_path = rustc_target::target_rustlib_path(&self.sysroot, &config::host_triple());
+        let p = std::array::IntoIter::new([
+            Path::new(&self.sysroot),
+            Path::new(&rustlib_path),
+            Path::new("bin"),
+        ])
+        .collect::<PathBuf>();
+        if self_contained { vec![p.clone(), p.join("self-contained")] } else { vec![p] }
+    }
+
     pub fn init_incr_comp_session(
         &self,
         session_dir: PathBuf,
@@ -1245,11 +1255,13 @@ pub fn build_session(
 
     let host_triple = config::host_triple();
     let target_triple = sopts.target_triple.triple();
-    let host_tlib_path = SearchPath::from_sysroot_and_triple(&sysroot, host_triple);
+    let host_tlib_path = Lrc::new(SearchPath::from_sysroot_and_triple(&sysroot, host_triple));
     let target_tlib_path = if host_triple == target_triple {
-        None
+        // Use the same `SearchPath` if host and target triple are identical to avoid unnecessary
+        // rescanning of the target lib path and an unnecessary allocation.
+        host_tlib_path.clone()
     } else {
-        Some(SearchPath::from_sysroot_and_triple(&sysroot, target_triple))
+        Lrc::new(SearchPath::from_sysroot_and_triple(&sysroot, target_triple))
     };
 
     let file_path_mapping = sopts.file_path_mapping();