Make real_rust_path_dir a TRACKED_NO_CRATE_HASH option

This also adds support for doc-comments to Options.

compiler/rustc_interface/src/tests.rs

@@ -459,6 +459,10 @@ fn test_top_level_options_tracked_no_crate() {
     // Make sure that changing a [TRACKED_NO_CRATE_HASH] option leaves the crate hash unchanged but changes the incremental hash.
     // This list is in alphabetical order.
     tracked!(remap_path_prefix, vec![("/home/bors/rust".into(), "src".into())]);
+    tracked!(
+        real_rust_source_base_dir,
+        Some("/home/bors/rust/.rustup/toolchains/nightly/lib/rustlib/src/rust".into())
+    );
 }
 
 #[test]

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -1617,7 +1617,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             .map(Path::new)
             .filter(|_| {
                 // Only spend time on further checks if we have what to translate *to*.
-                sess.real_rust_source_base_dir.is_some()
+                sess.opts.real_rust_source_base_dir.is_some()
             })
             .filter(|virtual_dir| {
                 // Don't translate away `/rustc/$hash` if we're still remapping to it,
@@ -1629,11 +1629,11 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             debug!(
                 "try_to_translate_virtual_to_real(name={:?}): \
                  virtual_rust_source_base_dir={:?}, real_rust_source_base_dir={:?}",
-                name, virtual_rust_source_base_dir, sess.real_rust_source_base_dir,
+                name, virtual_rust_source_base_dir, sess.opts.real_rust_source_base_dir,
             );
 
             if let Some(virtual_dir) = virtual_rust_source_base_dir {
-                if let Some(real_dir) = &sess.real_rust_source_base_dir {
+                if let Some(real_dir) = &sess.opts.real_rust_source_base_dir {
                     if let rustc_span::FileName::Real(old_name) = name {
                         if let rustc_span::RealFileName::Named(one_path) = old_name {
                             if let Ok(rest) = one_path.strip_prefix(virtual_dir) {

compiler/rustc_session/src/config.rs

@@ -702,6 +702,7 @@ impl Default for Options {
             cli_forced_codegen_units: None,
             cli_forced_thinlto_off: false,
             remap_path_prefix: Vec::new(),
+            real_rust_source_base_dir: None,
             edition: DEFAULT_EDITION,
             json_artifact_notifications: false,
             json_unused_externs: false,
@@ -1980,6 +1981,34 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         }
     }
 
+    // Try to find a directory containing the Rust `src`, for more details see
+    // the doc comment on the `real_rust_source_base_dir` field.
+    let tmp_buf;
+    let sysroot = match &sysroot_opt {
+        Some(s) => s,
+        None => {
+            tmp_buf = crate::filesearch::get_or_default_sysroot();
+            &tmp_buf
+        }
+    };
+    let real_rust_source_base_dir = {
+        // This is the location used by the `rust-src` `rustup` component.
+        let mut candidate = sysroot.join("lib/rustlib/src/rust");
+        if let Ok(metadata) = candidate.symlink_metadata() {
+            // Replace the symlink rustbuild creates, with its destination.
+            // We could try to use `fs::canonicalize` instead, but that might
+            // produce unnecessarily verbose path.
+            if metadata.file_type().is_symlink() {
+                if let Ok(symlink_dest) = std::fs::read_link(&candidate) {
+                    candidate = symlink_dest;
+                }
+            }
+        }
+
+        // Only use this directory if it has a file we can expect to always find.
+        if candidate.join("library/std/src/lib.rs").is_file() { Some(candidate) } else { None }
+    };
+
     Options {
         crate_types,
         optimize: opt_level,
@@ -2010,6 +2039,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         cli_forced_codegen_units: codegen_units,
         cli_forced_thinlto_off: disable_thinlto,
         remap_path_prefix,
+        real_rust_source_base_dir,
         edition,
         json_artifact_notifications,
         json_unused_externs,

compiler/rustc_session/src/options.rs

@@ -54,11 +54,15 @@ macro_rules! hash_substruct {
 
 macro_rules! top_level_options {
     (pub struct Options { $(
+        $( #[$attr:meta] )*
         $opt:ident : $t:ty [$dep_tracking_marker:ident],
     )* } ) => (
         #[derive(Clone)]
         pub struct Options {
-            $(pub $opt: $t),*
+            $(
+                $( #[$attr] )*
+                pub $opt: $t
+            ),*
         }
 
         impl Options {
@@ -174,6 +178,14 @@ top_level_options!(
 
         // Remap source path prefixes in all output (messages, object files, debug, etc.).
         remap_path_prefix: Vec<(PathBuf, PathBuf)> [TRACKED_NO_CRATE_HASH],
+        /// Base directory containing the `src/` for the Rust standard library, and
+        /// potentially `rustc` as well, if we can can find it. Right now it's always
+        /// `$sysroot/lib/rustlib/src/rust` (i.e. the `rustup` `rust-src` component).
+        ///
+        /// This directory is what the virtual `/rustc/$hash` is translated back to,
+        /// if Rust was built with path remapping to `/rustc/$hash` enabled
+        /// (the `rust.remap-debuginfo` option in `config.toml`).
+        real_rust_source_base_dir: Option<PathBuf> [TRACKED_NO_CRATE_HASH],
 
         edition: Edition [TRACKED],
 
@@ -254,13 +266,13 @@ macro_rules! options {
     }
 
     impl $struct_name {
-        fn dep_tracking_hash(&self, for_crate_hash: bool, error_format: ErrorOutputType) -> u64 {
+        fn dep_tracking_hash(&self, _for_crate_hash: bool, error_format: ErrorOutputType) -> u64 {
             let mut sub_hashes = BTreeMap::new();
             $({
                 hash_opt!($opt,
                             &self.$opt,
                             &mut sub_hashes,
-                            for_crate_hash,
+                            _for_crate_hash,
                             [$dep_tracking_marker]);
             })*
             let mut hasher = DefaultHasher::new();

compiler/rustc_session/src/session.rs

@@ -214,15 +214,6 @@ pub struct Session {
     /// drown everything else in noise.
     miri_unleashed_features: Lock<Vec<(Span, Option<Symbol>)>>,
 
-    /// Base directory containing the `src/` for the Rust standard library, and
-    /// potentially `rustc` as well, if we can can find it. Right now it's always
-    /// `$sysroot/lib/rustlib/src/rust` (i.e. the `rustup` `rust-src` component).
-    ///
-    /// This directory is what the virtual `/rustc/$hash` is translated back to,
-    /// if Rust was built with path remapping to `/rustc/$hash` enabled
-    /// (the `rust.remap-debuginfo` option in `config.toml`).
-    pub real_rust_source_base_dir: Option<PathBuf>,
-
     /// Architecture to use for interpreting asm!.
     pub asm_arch: Option<InlineAsmArch>,
 
@@ -1390,26 +1381,6 @@ pub fn build_session(
         _ => CtfeBacktrace::Disabled,
     });
 
-    // Try to find a directory containing the Rust `src`, for more details see
-    // the doc comment on the `real_rust_source_base_dir` field.
-    let real_rust_source_base_dir = {
-        // This is the location used by the `rust-src` `rustup` component.
-        let mut candidate = sysroot.join("lib/rustlib/src/rust");
-        if let Ok(metadata) = candidate.symlink_metadata() {
-            // Replace the symlink rustbuild creates, with its destination.
-            // We could try to use `fs::canonicalize` instead, but that might
-            // produce unnecessarily verbose path.
-            if metadata.file_type().is_symlink() {
-                if let Ok(symlink_dest) = std::fs::read_link(&candidate) {
-                    candidate = symlink_dest;
-                }
-            }
-        }
-
-        // Only use this directory if it has a file we can expect to always find.
-        if candidate.join("library/std/src/lib.rs").is_file() { Some(candidate) } else { None }
-    };
-
     let asm_arch =
         if target_cfg.allow_asm { InlineAsmArch::from_str(&target_cfg.arch).ok() } else { None };
 
@@ -1453,7 +1424,6 @@ pub fn build_session(
         system_library_path: OneThread::new(RefCell::new(Default::default())),
         ctfe_backtrace,
         miri_unleashed_features: Lock::new(Default::default()),
-        real_rust_source_base_dir,
         asm_arch,
         target_features: FxHashSet::default(),
         known_attrs: Lock::new(MarkedAttrs::new()),