Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 118 insertions, 0 deletions

diff --git a/compiler/rustc_session/src/cgu_reuse_tracker.rs b/compiler/rustc_session/src/cgu_reuse_tracker.rs
new file mode 100644
index 000000000..dd64e8ab7
--- /dev/null
+++ b/compiler/rustc_session/src/cgu_reuse_tracker.rs
@@ -0,0 +1,118 @@
+//! Some facilities for tracking how codegen-units are reused during incremental
+//! compilation. This is used for incremental compilation tests and debug
+//! output.
+
+use rustc_data_structures::fx::FxHashMap;
+use rustc_span::{Span, Symbol};
+use std::sync::{Arc, Mutex};
+use tracing::debug;
+
+#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
+pub enum CguReuse {
+    No,
+    PreLto,
+    PostLto,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum ComparisonKind {
+    Exact,
+    AtLeast,
+}
+
+struct TrackerData {
+    actual_reuse: FxHashMap<String, CguReuse>,
+    expected_reuse: FxHashMap<String, (String, SendSpan, CguReuse, ComparisonKind)>,
+}
+
+// Span does not implement `Send`, so we can't just store it in the shared
+// `TrackerData` object. Instead of splitting up `TrackerData` into shared and
+// non-shared parts (which would be complicated), we just mark the `Span` here
+// explicitly as `Send`. That's safe because the span data here is only ever
+// accessed from the main thread.
+struct SendSpan(Span);
+unsafe impl Send for SendSpan {}
+
+#[derive(Clone)]
+pub struct CguReuseTracker {
+    data: Option<Arc<Mutex<TrackerData>>>,
+}
+
+impl CguReuseTracker {
+    pub fn new() -> CguReuseTracker {
+        let data =
+            TrackerData { actual_reuse: Default::default(), expected_reuse: Default::default() };
+
+        CguReuseTracker { data: Some(Arc::new(Mutex::new(data))) }
+    }
+
+    pub fn new_disabled() -> CguReuseTracker {
+        CguReuseTracker { data: None }
+    }
+
+    pub fn set_actual_reuse(&self, cgu_name: &str, kind: CguReuse) {
+        if let Some(ref data) = self.data {
+            debug!("set_actual_reuse({cgu_name:?}, {kind:?})");
+
+            let prev_reuse = data.lock().unwrap().actual_reuse.insert(cgu_name.to_string(), kind);
+
+            if let Some(prev_reuse) = prev_reuse {
+                // The only time it is legal to overwrite reuse state is when
+                // we discover during ThinLTO that we can actually reuse the
+                // post-LTO version of a CGU.
+                assert_eq!(prev_reuse, CguReuse::PreLto);
+            }
+        }
+    }
+
+    pub fn set_expectation(
+        &self,
+        cgu_name: Symbol,
+        cgu_user_name: &str,
+        error_span: Span,
+        expected_reuse: CguReuse,
+        comparison_kind: ComparisonKind,
+    ) {
+        if let Some(ref data) = self.data {
+            debug!("set_expectation({cgu_name:?}, {expected_reuse:?}, {comparison_kind:?})");
+            let mut data = data.lock().unwrap();
+
+            data.expected_reuse.insert(
+                cgu_name.to_string(),
+                (cgu_user_name.to_string(), SendSpan(error_span), expected_reuse, comparison_kind),
+            );
+        }
+    }
+
+    pub fn check_expected_reuse(&self, diag: &rustc_errors::Handler) {
+        if let Some(ref data) = self.data {
+            let data = data.lock().unwrap();
+
+            for (cgu_name, &(ref cgu_user_name, ref error_span, expected_reuse, comparison_kind)) in
+                &data.expected_reuse
+            {
+                if let Some(&actual_reuse) = data.actual_reuse.get(cgu_name) {
+                    let (error, at_least) = match comparison_kind {
+                        ComparisonKind::Exact => (expected_reuse != actual_reuse, false),
+                        ComparisonKind::AtLeast => (actual_reuse < expected_reuse, true),
+                    };
+
+                    if error {
+                        let at_least = if at_least { "at least " } else { "" };
+                        let msg = format!(
+                            "CGU-reuse for `{cgu_user_name}` is `{actual_reuse:?}` but \
+                                           should be {at_least}`{expected_reuse:?}`"
+                        );
+                        diag.span_err(error_span.0, &msg);
+                    }
+                } else {
+                    let msg = format!(
+                        "CGU-reuse for `{cgu_user_name}` (mangled: `{cgu_name}`) was \
+                                       not recorded"
+                    );
+                    diag.span_fatal(error_span.0, &msg)
+                }
+            }
+        }
+    }
+}