6 files changed, 138 insertions, 3 deletions
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs
index 3889639b50f..447b73fa3c3 100644
--- a/compiler/rustc_span/src/hygiene.rs
+++ b/compiler/rustc_span/src/hygiene.rs
@@ -1132,6 +1132,7 @@ pub enum DesugaringKind {
     CondTemporary,
     QuestionMark,
     TryBlock,
+    YeetExpr,
     /// Desugaring of an `impl Trait` in return type position
     /// to an `type Foo = impl Trait;` and replacing the
     /// `impl Trait` with `Foo`.
@@ -1152,6 +1153,7 @@ impl DesugaringKind {
             DesugaringKind::Await => "`await` expression",
             DesugaringKind::QuestionMark => "operator `?`",
             DesugaringKind::TryBlock => "`try` block",
+            DesugaringKind::YeetExpr => "`do yeet` expression",
             DesugaringKind::OpaqueTy => "`impl Trait`",
             DesugaringKind::ForLoop => "`for` loop",
             DesugaringKind::LetElse => "`let...else`",
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index b132c0a2132..f22faef2580 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -59,6 +59,8 @@ pub use symbol::{sym, Symbol};
 mod analyze_source_file;
 pub mod fatal_error;
 
+pub mod profiling;
+
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::{Lock, Lrc};
 
@@ -1130,6 +1132,7 @@ impl ExternalSource {
 pub struct OffsetOverflowError;
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable)]
+#[derive(HashStable_Generic)]
 pub enum SourceFileHashAlgorithm {
     Md5,
     Sha1,
@@ -1149,8 +1152,6 @@ impl FromStr for SourceFileHashAlgorithm {
     }
 }
 
-rustc_data_structures::impl_stable_hash_via_hash!(SourceFileHashAlgorithm);
-
 /// The hash of the on-disk source file used for debug info.
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 #[derive(HashStable_Generic, Encodable, Decodable)]
diff --git a/compiler/rustc_span/src/profiling.rs b/compiler/rustc_span/src/profiling.rs
new file mode 100644
index 00000000000..f169007fab4
--- /dev/null
+++ b/compiler/rustc_span/src/profiling.rs
@@ -0,0 +1,35 @@
+use std::borrow::Borrow;
+
+use rustc_data_structures::profiling::EventArgRecorder;
+
+/// Extension trait for self-profiling purposes: allows to record spans within a generic activity's
+/// event arguments.
+pub trait SpannedEventArgRecorder {
+    /// Records the following event arguments within the current generic activity being profiled:
+    /// - the provided `event_arg`
+    /// - a string representation of the provided `span`
+    ///
+    /// Note: when self-profiling with costly event arguments, at least one argument
+    /// needs to be recorded. A panic will be triggered if that doesn't happen.
+    fn record_arg_with_span<A>(&mut self, event_arg: A, span: crate::Span)
+    where
+        A: Borrow<str> + Into<String>;
+}
+
+impl SpannedEventArgRecorder for EventArgRecorder<'_> {
+    fn record_arg_with_span<A>(&mut self, event_arg: A, span: crate::Span)
+    where
+        A: Borrow<str> + Into<String>,
+    {
+        self.record_arg(event_arg);
+
+        let span_arg = crate::with_session_globals(|session_globals| {
+            if let Some(source_map) = &*session_globals.source_map.borrow() {
+                source_map.span_to_embeddable_string(span)
+            } else {
+                format!("{:?}", span)
+            }
+        });
+        self.record_arg(span_arg);
+    }
+}
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index 95177102dcf..460b5c18fc1 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -1102,7 +1102,19 @@ impl FilePathMapping {
         //       take precedence.
         for &(ref from, ref to) in self.mapping.iter().rev() {
             if let Ok(rest) = path.strip_prefix(from) {
-                return (to.join(rest), true);
+                let remapped = if rest.as_os_str().is_empty() {
+                    // This is subtle, joining an empty path onto e.g. `foo/bar` will
+                    // result in `foo/bar/`, that is, there'll be an additional directory
+                    // separator at the end. This can lead to duplicated directory separators
+                    // in remapped paths down the line.
+                    // So, if we have an exact match, we just return that without a call
+                    // to `Path::join()`.
+                    to.clone()
+                } else {
+                    to.join(rest)
+                };
+
+                return (remapped, true);
             }
         }
 
diff --git a/compiler/rustc_span/src/source_map/tests.rs b/compiler/rustc_span/src/source_map/tests.rs
index f13979941ab..481e015c66c 100644
--- a/compiler/rustc_span/src/source_map/tests.rs
+++ b/compiler/rustc_span/src/source_map/tests.rs
@@ -312,3 +312,83 @@ impl SourceMapExtension for SourceMap {
         }
     }
 }
+
+fn map_path_prefix(mapping: &FilePathMapping, path: &str) -> String {
+    // It's important that we convert to a string here because that's what
+    // later stages do too (e.g. in the backend), and comparing `Path` values
+    // won't catch some differences at the string level, e.g. "abc" and "abc/"
+    // compare as equal.
+    mapping.map_prefix(path.into()).0.to_string_lossy().to_string()
+}
+
+#[cfg(unix)]
+#[test]
+fn path_prefix_remapping() {
+    // Relative to relative
+    {
+        let mapping = &FilePathMapping::new(vec![("abc/def".into(), "foo".into())]);
+
+        assert_eq!(map_path_prefix(mapping, "abc/def/src/main.rs"), "foo/src/main.rs");
+        assert_eq!(map_path_prefix(mapping, "abc/def"), "foo");
+    }
+
+    // Relative to absolute
+    {
+        let mapping = &FilePathMapping::new(vec![("abc/def".into(), "/foo".into())]);
+
+        assert_eq!(map_path_prefix(mapping, "abc/def/src/main.rs"), "/foo/src/main.rs");
+        assert_eq!(map_path_prefix(mapping, "abc/def"), "/foo");
+    }
+
+    // Absolute to relative
+    {
+        let mapping = &FilePathMapping::new(vec![("/abc/def".into(), "foo".into())]);
+
+        assert_eq!(map_path_prefix(mapping, "/abc/def/src/main.rs"), "foo/src/main.rs");
+        assert_eq!(map_path_prefix(mapping, "/abc/def"), "foo");
+    }
+
+    // Absolute to absolute
+    {
+        let mapping = &FilePathMapping::new(vec![("/abc/def".into(), "/foo".into())]);
+
+        assert_eq!(map_path_prefix(mapping, "/abc/def/src/main.rs"), "/foo/src/main.rs");
+        assert_eq!(map_path_prefix(mapping, "/abc/def"), "/foo");
+    }
+}
+
+#[cfg(windows)]
+#[test]
+fn path_prefix_remapping_from_relative2() {
+    // Relative to relative
+    {
+        let mapping = &FilePathMapping::new(vec![("abc\\def".into(), "foo".into())]);
+
+        assert_eq!(map_path_prefix(mapping, "abc\\def\\src\\main.rs"), "foo\\src\\main.rs");
+        assert_eq!(map_path_prefix(mapping, "abc\\def"), "foo");
+    }
+
+    // Relative to absolute
+    {
+        let mapping = &FilePathMapping::new(vec![("abc\\def".into(), "X:\\foo".into())]);
+
+        assert_eq!(map_path_prefix(mapping, "abc\\def\\src\\main.rs"), "X:\\foo\\src\\main.rs");
+        assert_eq!(map_path_prefix(mapping, "abc\\def"), "X:\\foo");
+    }
+
+    // Absolute to relative
+    {
+        let mapping = &FilePathMapping::new(vec![("X:\\abc\\def".into(), "foo".into())]);
+
+        assert_eq!(map_path_prefix(mapping, "X:\\abc\\def\\src\\main.rs"), "foo\\src\\main.rs");
+        assert_eq!(map_path_prefix(mapping, "X:\\abc\\def"), "foo");
+    }
+
+    // Absolute to absolute
+    {
+        let mapping = &FilePathMapping::new(vec![("X:\\abc\\def".into(), "X:\\foo".into())]);
+
+        assert_eq!(map_path_prefix(mapping, "X:\\abc\\def\\src\\main.rs"), "X:\\foo\\src\\main.rs");
+        assert_eq!(map_path_prefix(mapping, "X:\\abc\\def"), "X:\\foo");
+    }
+}
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index d9bada29589..c1299c94c4b 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -101,6 +101,7 @@ symbols! {
         MacroRules:         "macro_rules",
         Raw:                "raw",
         Union:              "union",
+        Yeet:               "yeet",
     }
 
     // Pre-interned symbols that can be referred to with `rustc_span::sym::*`.
@@ -714,6 +715,7 @@ symbols! {
         from_residual,
         from_size_align_unchecked,
         from_usize,
+        from_yeet,
         fsub_fast,
         fundamental,
         future,
@@ -803,6 +805,7 @@ symbols! {
         keyword,
         kind,
         kreg,
+        kreg0,
         label,
         label_break_value,
         lang,
@@ -1533,6 +1536,8 @@ symbols! {
         x87_reg,
         xer,
         xmm_reg,
+        yeet_desugar_details,
+        yeet_expr,
         ymm_reg,
         zmm_reg,
     }