linker: Remove laziness and caching from native search directory walks

It shouldn't be necessary for performance now.

Author: petrochenkov

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -42,7 +42,6 @@ use regex::Regex;
 use tempfile::Builder as TempFileBuilder;
 
 use itertools::Itertools;
-use std::cell::OnceCell;
 use std::collections::BTreeSet;
 use std::ffi::{OsStr, OsString};
 use std::fs::{read, File, OpenOptions};
@@ -52,20 +51,6 @@ use std::path::{Path, PathBuf};
 use std::process::{ExitStatus, Output, Stdio};
 use std::{env, fmt, fs, io, mem, str};
 
-#[derive(Default)]
-pub struct SearchPaths(OnceCell<Vec<PathBuf>>);
-
-impl SearchPaths {
-    pub(super) fn get(&self, sess: &Session) -> impl Iterator<Item = &Path> {
-        let native_search_paths = || {
-            Vec::from_iter(
-                sess.target_filesearch(PathKind::Native).search_path_dirs().map(|p| p.to_owned()),
-            )
-        };
-        self.0.get_or_init(native_search_paths).iter().map(|p| &**p)
-    }
-}
-
 pub fn ensure_removed(dcx: &DiagCtxt, path: &Path) {
     if let Err(e) = fs::remove_file(path) {
         if e.kind() != io::ErrorKind::NotFound {
@@ -381,24 +366,21 @@ fn link_rlib<'a>(
     // feature then we'll need to figure out how to record what objects were
     // loaded from the libraries found here and then encode that into the
     // metadata of the rlib we're generating somehow.
-    let search_paths = SearchPaths::default();
     for lib in codegen_results.crate_info.used_libraries.iter() {
         let NativeLibKind::Static { bundle: None | Some(true), .. } = lib.kind else {
             continue;
         };
-        let search_paths = search_paths.get(sess);
         if flavor == RlibFlavor::Normal
             && let Some(filename) = lib.filename
         {
-            let path = find_native_static_library(filename.as_str(), true, search_paths, sess);
+            let path = find_native_static_library(filename.as_str(), true, sess);
             let src = read(path)
                 .map_err(|e| sess.dcx().emit_fatal(errors::ReadFileError { message: e }))?;
             let (data, _) = create_wrapper_file(sess, ".bundled_lib".to_string(), &src);
             let wrapper_file = emit_wrapper_file(sess, &data, tmpdir, filename.as_str());
             packed_bundled_libs.push(wrapper_file);
         } else {
-            let path =
-                find_native_static_library(lib.name.as_str(), lib.verbatim, search_paths, sess);
+            let path = find_native_static_library(lib.name.as_str(), lib.verbatim, sess);
             ab.add_archive(&path, Box::new(|_| false)).unwrap_or_else(|error| {
                 sess.dcx().emit_fatal(errors::AddNativeLibrary { library_path: path, error })
             });
@@ -2497,7 +2479,6 @@ fn add_native_libs_from_crate(
     archive_builder_builder: &dyn ArchiveBuilderBuilder,
     codegen_results: &CodegenResults,
     tmpdir: &Path,
-    search_paths: &SearchPaths,
     bundled_libs: &FxIndexSet<Symbol>,
     cnum: CrateNum,
     link_static: bool,
@@ -2560,7 +2541,7 @@ fn add_native_libs_from_crate(
                             cmd.link_staticlib_by_path(&path, whole_archive);
                         }
                     } else {
-                        cmd.link_staticlib_by_name(name, verbatim, whole_archive, search_paths);
+                        cmd.link_staticlib_by_name(name, verbatim, whole_archive);
                     }
                 }
             }
@@ -2574,7 +2555,7 @@ fn add_native_libs_from_crate(
                 // link kind is unspecified.
                 if !link_output_kind.can_link_dylib() && !sess.target.crt_static_allows_dylibs {
                     if link_static {
-                        cmd.link_staticlib_by_name(name, verbatim, false, search_paths);
+                        cmd.link_staticlib_by_name(name, verbatim, false);
                     }
                 } else {
                     if link_dynamic {
@@ -2621,7 +2602,6 @@ fn add_local_native_libraries(
         }
     }
 
-    let search_paths = SearchPaths::default();
     // All static and dynamic native library dependencies are linked to the local crate.
     let link_static = true;
     let link_dynamic = true;
@@ -2631,7 +2611,6 @@ fn add_local_native_libraries(
         archive_builder_builder,
         codegen_results,
         tmpdir,
-        &search_paths,
         &Default::default(),
         LOCAL_CRATE,
         link_static,
@@ -2663,7 +2642,6 @@ fn add_upstream_rust_crates<'a>(
         .find(|(ty, _)| *ty == crate_type)
         .expect("failed to find crate type in dependency format list");
 
-    let search_paths = SearchPaths::default();
     for &cnum in &codegen_results.crate_info.used_crates {
         // We may not pass all crates through to the linker. Some crates may appear statically in
         // an existing dylib, meaning we'll pick up all the symbols from the dylib.
@@ -2720,7 +2698,6 @@ fn add_upstream_rust_crates<'a>(
             archive_builder_builder,
             codegen_results,
             tmpdir,
-            &search_paths,
             &bundled_libs,
             cnum,
             link_static,
@@ -2738,7 +2715,6 @@ fn add_upstream_native_libraries(
     tmpdir: &Path,
     link_output_kind: LinkOutputKind,
 ) {
-    let search_paths = SearchPaths::default();
     for &cnum in &codegen_results.crate_info.used_crates {
         // Static libraries are not linked here, they are linked in `add_upstream_rust_crates`.
         // FIXME: Merge this function to `add_upstream_rust_crates` so that all native libraries
@@ -2760,7 +2736,6 @@ fn add_upstream_native_libraries(
             archive_builder_builder,
             codegen_results,
             tmpdir,
-            &search_paths,
             &Default::default(),
             cnum,
             link_static,

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -1,6 +1,5 @@
 use super::command::Command;
 use super::symbol_export;
-use crate::back::link::SearchPaths;
 use crate::errors;
 use rustc_span::symbol::sym;
 
@@ -172,13 +171,7 @@ pub trait Linker {
     fn link_framework_by_name(&mut self, _name: &str, _verbatim: bool, _as_needed: bool) {
         bug!("framework linked with unsupported linker")
     }
-    fn link_staticlib_by_name(
-        &mut self,
-        name: &str,
-        verbatim: bool,
-        whole_archive: bool,
-        search_paths: &SearchPaths,
-    );
+    fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool);
     fn link_staticlib_by_path(&mut self, path: &Path, whole_archive: bool);
     fn include_path(&mut self, path: &Path);
     fn framework_path(&mut self, path: &Path);
@@ -482,13 +475,7 @@ impl<'a> Linker for GccLinker<'a> {
         self.cmd.arg("-framework").arg(name);
     }
 
-    fn link_staticlib_by_name(
-        &mut self,
-        name: &str,
-        verbatim: bool,
-        whole_archive: bool,
-        search_paths: &SearchPaths,
-    ) {
+    fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool) {
         self.hint_static();
         let colon = if verbatim && self.is_gnu { ":" } else { "" };
         if !whole_archive {
@@ -497,8 +484,7 @@ impl<'a> Linker for GccLinker<'a> {
             // -force_load is the macOS equivalent of --whole-archive, but it
             // involves passing the full path to the library to link.
             self.linker_arg("-force_load");
-            let search_paths = search_paths.get(self.sess);
-            self.linker_arg(find_native_static_library(name, verbatim, search_paths, self.sess));
+            self.linker_arg(find_native_static_library(name, verbatim, self.sess));
         } else {
             self.linker_arg("--whole-archive");
             self.cmd.arg(format!("-l{colon}{name}"));
@@ -825,13 +811,7 @@ impl<'a> Linker for MsvcLinker<'a> {
         self.cmd.arg(format!("{}{}", name, if verbatim { "" } else { ".lib" }));
     }
 
-    fn link_staticlib_by_name(
-        &mut self,
-        name: &str,
-        verbatim: bool,
-        whole_archive: bool,
-        _search_paths: &SearchPaths,
-    ) {
+    fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool) {
         let prefix = if whole_archive { "/WHOLEARCHIVE:" } else { "" };
         let suffix = if verbatim { "" } else { ".lib" };
         self.cmd.arg(format!("{prefix}{name}{suffix}"));
@@ -1064,13 +1044,7 @@ impl<'a> Linker for EmLinker<'a> {
         self.cmd.arg("-l").arg(name);
     }
 
-    fn link_staticlib_by_name(
-        &mut self,
-        name: &str,
-        _verbatim: bool,
-        _whole_archive: bool,
-        _search_paths: &SearchPaths,
-    ) {
+    fn link_staticlib_by_name(&mut self, name: &str, _verbatim: bool, _whole_archive: bool) {
         self.cmd.arg("-l").arg(name);
     }
 
@@ -1243,13 +1217,7 @@ impl<'a> Linker for WasmLd<'a> {
         self.cmd.arg("-l").arg(name);
     }
 
-    fn link_staticlib_by_name(
-        &mut self,
-        name: &str,
-        _verbatim: bool,
-        whole_archive: bool,
-        _search_paths: &SearchPaths,
-    ) {
+    fn link_staticlib_by_name(&mut self, name: &str, _verbatim: bool, whole_archive: bool) {
         if !whole_archive {
             self.cmd.arg("-l").arg(name);
         } else {
@@ -1396,13 +1364,7 @@ impl<'a> Linker for L4Bender<'a> {
         bug!("dylibs are not supported on L4Re");
     }
 
-    fn link_staticlib_by_name(
-        &mut self,
-        name: &str,
-        _verbatim: bool,
-        whole_archive: bool,
-        _search_paths: &SearchPaths,
-    ) {
+    fn link_staticlib_by_name(&mut self, name: &str, _verbatim: bool, whole_archive: bool) {
         self.hint_static();
         if !whole_archive {
             self.cmd.arg(format!("-PC{name}"));
@@ -1580,20 +1542,13 @@ impl<'a> Linker for AixLinker<'a> {
         self.cmd.arg(format!("-l{name}"));
     }
 
-    fn link_staticlib_by_name(
-        &mut self,
-        name: &str,
-        verbatim: bool,
-        whole_archive: bool,
-        search_paths: &SearchPaths,
-    ) {
+    fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool) {
         self.hint_static();
         if !whole_archive {
             self.cmd.arg(format!("-l{name}"));
         } else {
             let mut arg = OsString::from("-bkeepfile:");
-            let search_path = search_paths.get(self.sess);
-            arg.push(find_native_static_library(name, verbatim, search_path, self.sess));
+            arg.push(find_native_static_library(name, verbatim, self.sess));
             self.cmd.arg(arg);
         }
     }
@@ -1792,13 +1747,7 @@ impl<'a> Linker for PtxLinker<'a> {
         panic!("external dylibs not supported")
     }
 
-    fn link_staticlib_by_name(
-        &mut self,
-        _name: &str,
-        _verbatim: bool,
-        _whole_archive: bool,
-        _search_paths: &SearchPaths,
-    ) {
+    fn link_staticlib_by_name(&mut self, _name: &str, _verbatim: bool, _whole_archive: bool) {
         panic!("staticlibs not supported")
     }
 
@@ -1880,13 +1829,7 @@ impl<'a> Linker for LlbcLinker<'a> {
         panic!("external dylibs not supported")
     }
 
-    fn link_staticlib_by_name(
-        &mut self,
-        _name: &str,
-        _verbatim: bool,
-        _whole_archive: bool,
-        _search_paths: &SearchPaths,
-    ) {
+    fn link_staticlib_by_name(&mut self, _name: &str, _verbatim: bool, _whole_archive: bool) {
         panic!("staticlibs not supported")
     }
 
@@ -1977,13 +1920,7 @@ impl<'a> Linker for BpfLinker<'a> {
         panic!("external dylibs not supported")
     }
 
-    fn link_staticlib_by_name(
-        &mut self,
-        _name: &str,
-        _verbatim: bool,
-        _whole_archive: bool,
-        _search_paths: &SearchPaths,
-    ) {
+    fn link_staticlib_by_name(&mut self, _name: &str, _verbatim: bool, _whole_archive: bool) {
         panic!("staticlibs not supported")
     }
 

compiler/rustc_interface/src/passes.rs

@@ -171,7 +171,7 @@ fn configure_and_expand(
         if cfg!(windows) {
             old_path = env::var_os("PATH").unwrap_or(old_path);
             let mut new_path = Vec::from_iter(
-                sess.host_filesearch(PathKind::All).search_path_dirs().map(|p| p.to_owned()),
+                sess.host_filesearch(PathKind::All).search_paths().map(|p| p.dir.clone()),
             );
             for path in env::split_paths(&old_path) {
                 if !new_path.contains(&path) {

compiler/rustc_metadata/src/native_libs.rs

@@ -17,14 +17,9 @@ use rustc_target::spec::abi::Abi;
 
 use crate::errors;
 
-use std::path::{Path, PathBuf};
-
-pub fn find_native_static_library<'a>(
-    name: &str,
-    verbatim: bool,
-    search_paths: impl Iterator<Item = &'a Path>,
-    sess: &Session,
-) -> PathBuf {
+use std::path::PathBuf;
+
+pub fn find_native_static_library(name: &str, verbatim: bool, sess: &Session) -> PathBuf {
     let formats = if verbatim {
         vec![("".into(), "".into())]
     } else {
@@ -35,9 +30,9 @@ pub fn find_native_static_library<'a>(
         if os == unix { vec![os] } else { vec![os, unix] }
     };
 
-    for path in search_paths {
+    for path in sess.target_filesearch(PathKind::Native).search_paths() {
         for (prefix, suffix) in &formats {
-            let test = path.join(format!("{prefix}{name}{suffix}"));
+            let test = path.dir.join(format!("{prefix}{name}{suffix}"));
             if test.exists() {
                 return test;
             }
@@ -60,8 +55,7 @@ fn find_bundled_library(
         && (sess.opts.unstable_opts.packed_bundled_libs || has_cfg || whole_archive == Some(true))
     {
         let verbatim = verbatim.unwrap_or(false);
-        let search_paths = sess.target_filesearch(PathKind::Native).search_path_dirs();
-        return find_native_static_library(name.as_str(), verbatim, search_paths, sess)
+        return find_native_static_library(name.as_str(), verbatim, sess)
             .file_name()
             .and_then(|s| s.to_str())
             .map(Symbol::intern);

compiler/rustc_session/src/filesearch.rs

@@ -45,11 +45,6 @@ impl<'a> FileSearch<'a> {
         debug!("using sysroot = {}, triple = {}", sysroot.display(), triple);
         FileSearch { sysroot, triple, search_paths, tlib_path, kind }
     }
-
-    /// Returns just the directories within the search paths.
-    pub fn search_path_dirs(&self) -> impl Iterator<Item = &'a Path> {
-        self.search_paths().map(|sp| &*sp.dir)
-    }
 }
 
 pub fn make_target_lib_path(sysroot: &Path, target_triple: &str) -> PathBuf {