Rollup merge of #138404 - bjorn3:sysroot_handling_cleanup, r=petrochenkov,jieyouxu

Cleanup sysroot locating a bit

All commits should preserve existing behavior.

compiler/rustc_session/src/config.rs

@@ -1214,7 +1214,7 @@ impl Default for Options {
             describe_lints: false,
             output_types: OutputTypes(BTreeMap::new()),
             search_paths: vec![],
-            maybe_sysroot: None,
+            sysroot: filesearch::materialize_sysroot(None),
             target_triple: TargetTuple::from_tuple(host_tuple()),
             test: false,
             incremental: None,
@@ -2618,7 +2618,7 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
         describe_lints,
         output_types,
         search_paths,
-        maybe_sysroot: Some(sysroot),
+        sysroot,
         target_triple,
         test,
         incremental,

compiler/rustc_session/src/filesearch.rs

@@ -160,8 +160,7 @@ fn current_dll_path() -> Result<PathBuf, String> {
 
 pub fn sysroot_candidates() -> SmallVec<[PathBuf; 2]> {
     let target = crate::config::host_tuple();
-    let mut sysroot_candidates: SmallVec<[PathBuf; 2]> =
-        smallvec![get_or_default_sysroot().expect("Failed finding sysroot")];
+    let mut sysroot_candidates: SmallVec<[PathBuf; 2]> = smallvec![get_or_default_sysroot()];
     let path = current_dll_path().and_then(|s| try_canonicalize(s).map_err(|e| e.to_string()));
     if let Ok(dll) = path {
         // use `parent` twice to chop off the file name and then also the
@@ -195,12 +194,12 @@ pub fn sysroot_candidates() -> SmallVec<[PathBuf; 2]> {
 /// Returns the provided sysroot or calls [`get_or_default_sysroot`] if it's none.
 /// Panics if [`get_or_default_sysroot`]  returns an error.
 pub fn materialize_sysroot(maybe_sysroot: Option<PathBuf>) -> PathBuf {
-    maybe_sysroot.unwrap_or_else(|| get_or_default_sysroot().expect("Failed finding sysroot"))
+    maybe_sysroot.unwrap_or_else(|| get_or_default_sysroot())
 }
 
 /// This function checks if sysroot is found using env::args().next(), and if it
 /// is not found, finds sysroot from current rustc_driver dll.
-pub fn get_or_default_sysroot() -> Result<PathBuf, String> {
+pub fn get_or_default_sysroot() -> PathBuf {
     // Follow symlinks. If the resolved path is relative, make it absolute.
     fn canonicalize(path: PathBuf) -> PathBuf {
         let path = try_canonicalize(&path).unwrap_or(path);
@@ -255,30 +254,25 @@ pub fn get_or_default_sysroot() -> Result<PathBuf, String> {
     // binary able to locate Rust libraries in systems using content-addressable
     // storage (CAS).
     fn from_env_args_next() -> Option<PathBuf> {
-        match env::args_os().next() {
-            Some(first_arg) => {
-                let mut p = PathBuf::from(first_arg);
+        let mut p = PathBuf::from(env::args_os().next()?);
 
-                // Check if sysroot is found using env::args().next() only if the rustc in argv[0]
-                // is a symlink (see #79253). We might want to change/remove it to conform with
-                // https://www.gnu.org/prep/standards/standards.html#Finding-Program-Files in the
-                // future.
-                if fs::read_link(&p).is_err() {
-                    // Path is not a symbolic link or does not exist.
-                    return None;
-                }
-
-                // Pop off `bin/rustc`, obtaining the suspected sysroot.
-                p.pop();
-                p.pop();
-                // Look for the target rustlib directory in the suspected sysroot.
-                let mut rustlib_path = rustc_target::relative_target_rustlib_path(&p, "dummy");
-                rustlib_path.pop(); // pop off the dummy target.
-                rustlib_path.exists().then_some(p)
-            }
-            None => None,
+        // Check if sysroot is found using env::args().next() only if the rustc in argv[0]
+        // is a symlink (see #79253). We might want to change/remove it to conform with
+        // https://www.gnu.org/prep/standards/standards.html#Finding-Program-Files in the
+        // future.
+        if fs::read_link(&p).is_err() {
+            // Path is not a symbolic link or does not exist.
+            return None;
         }
+
+        // Pop off `bin/rustc`, obtaining the suspected sysroot.
+        p.pop();
+        p.pop();
+        // Look for the target rustlib directory in the suspected sysroot.
+        let mut rustlib_path = rustc_target::relative_target_rustlib_path(&p, "dummy");
+        rustlib_path.pop(); // pop off the dummy target.
+        rustlib_path.exists().then_some(p)
     }
 
-    Ok(from_env_args_next().unwrap_or(default_from_rustc_driver_dll()?))
+    from_env_args_next().unwrap_or(default_from_rustc_driver_dll().expect("Failed finding sysroot"))
 }

compiler/rustc_session/src/options.rs

@@ -333,7 +333,7 @@ top_level_options!(
         output_types: OutputTypes [TRACKED],
         search_paths: Vec<SearchPath> [UNTRACKED],
         libs: Vec<NativeLib> [TRACKED],
-        maybe_sysroot: Option<PathBuf> [UNTRACKED],
+        sysroot: PathBuf [UNTRACKED],
 
         target_triple: TargetTuple [TRACKED],
 

compiler/rustc_session/src/session.rs

@@ -143,7 +143,6 @@ pub struct Session {
     pub target: Target,
     pub host: Target,
     pub opts: config::Options,
-    pub host_tlib_path: Arc<SearchPath>,
     pub target_tlib_path: Arc<SearchPath>,
     pub psess: ParseSess,
     pub sysroot: PathBuf,
@@ -1042,6 +1041,7 @@ pub fn build_session(
 
     let host_triple = config::host_tuple();
     let target_triple = sopts.target_triple.tuple();
+    // FIXME use host sysroot?
     let host_tlib_path = Arc::new(SearchPath::from_sysroot_and_triple(&sysroot, host_triple));
     let target_tlib_path = if host_triple == target_triple {
         // Use the same `SearchPath` if host and target triple are identical to avoid unnecessary
@@ -1070,7 +1070,6 @@ pub fn build_session(
         target,
         host,
         opts: sopts,
-        host_tlib_path,
         target_tlib_path,
         psess,
         sysroot,