Implement `-L builtin:$path`

4 files changed, 71 insertions, 31 deletions

diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 8a27e9a6453..8e43d6974fe 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -315,30 +315,39 @@ fn test_search_paths_tracking_hash_different_order() {
         json_rendered: HumanReadableErrorType::Default(ColorConfig::Never),
     };
 
+    let push = |opts: &mut Options, search_path| {
+        opts.search_paths.push(SearchPath::from_cli_opt(
+            None,
+            &opts.target_triple,
+            &early_dcx,
+            search_path,
+        ));
+    };
+
     // Reference
-    v1.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "native=abc"));
-    v1.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "crate=def"));
-    v1.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "dependency=ghi"));
-    v1.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "framework=jkl"));
-    v1.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "all=mno"));
-
-    v2.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "native=abc"));
-    v2.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "dependency=ghi"));
-    v2.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "crate=def"));
-    v2.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "framework=jkl"));
-    v2.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "all=mno"));
-
-    v3.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "crate=def"));
-    v3.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "framework=jkl"));
-    v3.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "native=abc"));
-    v3.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "dependency=ghi"));
-    v3.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "all=mno"));
-
-    v4.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "all=mno"));
-    v4.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "native=abc"));
-    v4.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "crate=def"));
-    v4.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "dependency=ghi"));
-    v4.search_paths.push(SearchPath::from_cli_opt(&early_dcx, "framework=jkl"));
+    push(&mut v1, "native=abc");
+    push(&mut v1, "crate=def");
+    push(&mut v1, "dependency=ghi");
+    push(&mut v1, "framework=jkl");
+    push(&mut v1, "all=mno");
+
+    push(&mut v2, "native=abc");
+    push(&mut v2, "dependency=ghi");
+    push(&mut v2, "crate=def");
+    push(&mut v2, "framework=jkl");
+    push(&mut v2, "all=mno");
+
+    push(&mut v3, "crate=def");
+    push(&mut v3, "framework=jkl");
+    push(&mut v3, "native=abc");
+    push(&mut v3, "dependency=ghi");
+    push(&mut v3, "all=mno");
+
+    push(&mut v4, "all=mno");
+    push(&mut v4, "native=abc");
+    push(&mut v4, "crate=def");
+    push(&mut v4, "dependency=ghi");
+    push(&mut v4, "framework=jkl");
 
     assert_same_hash(&v1, &v2);
     assert_same_hash(&v1, &v3);
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index c06fe29c567..79328659227 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -2795,11 +2795,6 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
     let debuginfo = select_debuginfo(matches, &cg);
     let debuginfo_compression = unstable_opts.debuginfo_compression;
 
-    let mut search_paths = vec![];
-    for s in &matches.opt_strs("L") {
-        search_paths.push(SearchPath::from_cli_opt(early_dcx, s));
-    }
-
     let libs = parse_libs(early_dcx, matches);
 
     let test = matches.opt_present("test");
@@ -2848,6 +2843,11 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
         candidate.join("library/std/src/lib.rs").is_file().then_some(candidate)
     };
 
+    let mut search_paths = vec![];
+    for s in &matches.opt_strs("L") {
+        search_paths.push(SearchPath::from_cli_opt(Some(&sysroot), &target_triple, early_dcx, s));
+    }
+
     let working_dir = std::env::current_dir().unwrap_or_else(|e| {
         early_dcx.early_fatal(format!("Current directory is invalid: {e}"));
     });
diff --git a/compiler/rustc_session/src/search_paths.rs b/compiler/rustc_session/src/search_paths.rs
index 32d5e430717..58b4a08b5b0 100644
--- a/compiler/rustc_session/src/search_paths.rs
+++ b/compiler/rustc_session/src/search_paths.rs
@@ -1,5 +1,6 @@
 use crate::filesearch::make_target_lib_path;
 use crate::EarlyDiagCtxt;
+use rustc_target::spec::TargetTriple;
 use std::path::{Path, PathBuf};
 
 #[derive(Clone, Debug)]
@@ -46,7 +47,12 @@ impl PathKind {
 }
 
 impl SearchPath {
-    pub fn from_cli_opt(early_dcx: &EarlyDiagCtxt, path: &str) -> Self {
+    pub fn from_cli_opt(
+        sysroot: Option<&Path>,
+        triple: &TargetTriple,
+        early_dcx: &EarlyDiagCtxt,
+        path: &str,
+    ) -> Self {
         let (kind, path) = if let Some(stripped) = path.strip_prefix("native=") {
             (PathKind::Native, stripped)
         } else if let Some(stripped) = path.strip_prefix("crate=") {
@@ -57,6 +63,27 @@ impl SearchPath {
             (PathKind::Framework, stripped)
         } else if let Some(stripped) = path.strip_prefix("all=") {
             (PathKind::All, stripped)
+        } else if let Some(stripped) = path.strip_prefix("builtin:") {
+            let Some(sysroot) = sysroot else {
+                early_dcx.early_fatal("`-L builtin:` is not supported without a sysroot present");
+            };
+            let triple = match triple {
+                TargetTriple::TargetTriple(triple) => triple,
+                TargetTriple::TargetJson { .. } => {
+                    early_dcx.early_fatal("`-L builtin:` is not supported with custom targets");
+                }
+            };
+
+            if stripped.contains(std::path::is_separator) {
+                early_dcx.early_fatal("`-L builtin:` does not accept paths");
+            }
+
+            let path = make_target_lib_path(sysroot, triple).join("builtin").join(stripped);
+            if !path.is_dir() {
+                early_dcx.early_fatal(format!("builtin:{stripped} does not exist"));
+            }
+
+            return Self::new(PathKind::All, path);
         } else {
             (PathKind::All, path)
         };
diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index be7e319bc79..ab793bb3062 100644
--- a/src/librustdoc/config.rs
+++ b/src/librustdoc/config.rs
@@ -460,8 +460,6 @@ impl Options {
             &matches.free[0]
         });
 
-        let libs =
-            matches.opt_strs("L").iter().map(|s| SearchPath::from_cli_opt(early_dcx, s)).collect();
         let externs = parse_externs(early_dcx, matches, &unstable_opts);
         let extern_html_root_urls = match parse_extern_html_roots(matches) {
             Ok(ex) => ex,
@@ -626,6 +624,12 @@ impl Options {
 
         let target = parse_target_triple(early_dcx, matches);
 
+        let libs = matches
+            .opt_strs("L")
+            .iter()
+            .map(|s| SearchPath::from_cli_opt(None, &target, early_dcx, s))
+            .collect();
+
         let show_coverage = matches.opt_present("show-coverage");
 
         let crate_types = match parse_crate_types_from_list(matches.opt_strs("crate-type")) {