New upstream version 1.57.0+dfsg1

[rustc.git] / compiler / rustc_mir_dataflow / src / framework / fmt.rs

diff --git a/compiler/rustc_mir_dataflow/src/framework/fmt.rs b/compiler/rustc_mir_dataflow/src/framework/fmt.rs
new file mode 100644 (file)
index 0000000..1d1553b
--- /dev/null
+++ b/compiler/rustc_mir_dataflow/src/framework/fmt.rs
@@ -0,0 +1,172 @@
+//! Custom formatting traits used when outputting Graphviz diagrams with the results of a dataflow
+//! analysis.
+
+use rustc_index::bit_set::{BitSet, HybridBitSet};
+use rustc_index::vec::Idx;
+use std::fmt;
+
+/// An extension to `fmt::Debug` for data that can be better printed with some auxiliary data `C`.
+pub trait DebugWithContext<C>: Eq + fmt::Debug {
+    fn fmt_with(&self, _ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(self, f)
+    }
+
+    /// Print the difference between `self` and `old`.
+    ///
+    /// This should print nothing if `self == old`.
+    ///
+    /// `+` and `-` are typically used to indicate differences. However, these characters are
+    /// fairly common and may be needed to print a types representation. If using them to indicate
+    /// a diff, prefix them with the "Unit Separator"  control character (␟  U+001F).
+    fn fmt_diff_with(&self, old: &Self, ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if self == old {
+            return Ok(());
+        }
+
+        write!(f, "\u{001f}+")?;
+        self.fmt_with(ctxt, f)?;
+
+        if f.alternate() {
+            write!(f, "\n")?;
+        } else {
+            write!(f, "\t")?;
+        }
+
+        write!(f, "\u{001f}-")?;
+        old.fmt_with(ctxt, f)
+    }
+}
+
+/// Implements `fmt::Debug` by deferring to `<T as DebugWithContext<C>>::fmt_with`.
+pub struct DebugWithAdapter<'a, T, C> {
+    pub this: T,
+    pub ctxt: &'a C,
+}
+
+impl<T, C> fmt::Debug for DebugWithAdapter<'_, T, C>
+where
+    T: DebugWithContext<C>,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.this.fmt_with(self.ctxt, f)
+    }
+}
+
+/// Implements `fmt::Debug` by deferring to `<T as DebugWithContext<C>>::fmt_diff_with`.
+pub struct DebugDiffWithAdapter<'a, T, C> {
+    pub new: T,
+    pub old: T,
+    pub ctxt: &'a C,
+}
+
+impl<T, C> fmt::Debug for DebugDiffWithAdapter<'_, T, C>
+where
+    T: DebugWithContext<C>,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.new.fmt_diff_with(&self.old, self.ctxt, f)
+    }
+}
+
+// Impls
+
+impl<T, C> DebugWithContext<C> for BitSet<T>
+where
+    T: Idx + DebugWithContext<C>,
+{
+    fn fmt_with(&self, ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_set().entries(self.iter().map(|i| DebugWithAdapter { this: i, ctxt })).finish()
+    }
+
+    fn fmt_diff_with(&self, old: &Self, ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let size = self.domain_size();
+        assert_eq!(size, old.domain_size());
+
+        let mut set_in_self = HybridBitSet::new_empty(size);
+        let mut cleared_in_self = HybridBitSet::new_empty(size);
+
+        for i in (0..size).map(T::new) {
+            match (self.contains(i), old.contains(i)) {
+                (true, false) => set_in_self.insert(i),
+                (false, true) => cleared_in_self.insert(i),
+                _ => continue,
+            };
+        }
+
+        let mut first = true;
+        for idx in set_in_self.iter() {
+            let delim = if first {
+                "\u{001f}+"
+            } else if f.alternate() {
+                "\n\u{001f}+"
+            } else {
+                ", "
+            };
+
+            write!(f, "{}", delim)?;
+            idx.fmt_with(ctxt, f)?;
+            first = false;
+        }
+
+        if !f.alternate() {
+            first = true;
+            if !set_in_self.is_empty() && !cleared_in_self.is_empty() {
+                write!(f, "\t")?;
+            }
+        }
+
+        for idx in cleared_in_self.iter() {
+            let delim = if first {
+                "\u{001f}-"
+            } else if f.alternate() {
+                "\n\u{001f}-"
+            } else {
+                ", "
+            };
+
+            write!(f, "{}", delim)?;
+            idx.fmt_with(ctxt, f)?;
+            first = false;
+        }
+
+        Ok(())
+    }
+}
+
+impl<T, C> DebugWithContext<C> for &'_ T
+where
+    T: DebugWithContext<C>,
+{
+    fn fmt_with(&self, ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        (*self).fmt_with(ctxt, f)
+    }
+
+    fn fmt_diff_with(&self, old: &Self, ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        (*self).fmt_diff_with(*old, ctxt, f)
+    }
+}
+
+impl<C> DebugWithContext<C> for rustc_middle::mir::Local {}
+impl<C> DebugWithContext<C> for crate::move_paths::InitIndex {}
+
+impl<'tcx, C> DebugWithContext<C> for crate::move_paths::MovePathIndex
+where
+    C: crate::move_paths::HasMoveData<'tcx>,
+{
+    fn fmt_with(&self, ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", ctxt.move_data().move_paths[*self])
+    }
+}
+
+impl<T, C> DebugWithContext<C> for crate::lattice::Dual<T>
+where
+    T: DebugWithContext<C>,
+{
+    fn fmt_with(&self, ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        (self.0).fmt_with(ctxt, f)
+    }
+
+    fn fmt_diff_with(&self, old: &Self, ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        (self.0).fmt_diff_with(&old.0, ctxt, f)
+    }
+}