Merging upstream version 1.72.1+dfsg1.

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

1 files changed, 75 insertions, 0 deletions

diff --git a/compiler/rustc_codegen_ssa/src/mir/locals.rs b/compiler/rustc_codegen_ssa/src/mir/locals.rs
new file mode 100644
index 000000000..378c54013
--- /dev/null
+++ b/compiler/rustc_codegen_ssa/src/mir/locals.rs
@@ -0,0 +1,75 @@
+//! Locals are in a private module as updating `LocalRef::Operand` has to
+//! be careful wrt to subtyping. To deal with this we only allow updates by using
+//! `FunctionCx::overwrite_local` which handles it automatically.
+use crate::mir::{FunctionCx, LocalRef};
+use crate::traits::BuilderMethods;
+use rustc_index::IndexVec;
+use rustc_middle::mir;
+use rustc_middle::ty::print::with_no_trimmed_paths;
+use std::ops::{Index, IndexMut};
+pub(super) struct Locals<'tcx, V> {
+    values: IndexVec<mir::Local, LocalRef<'tcx, V>>,
+}
+
+impl<'tcx, V> Index<mir::Local> for Locals<'tcx, V> {
+    type Output = LocalRef<'tcx, V>;
+    #[inline]
+    fn index(&self, index: mir::Local) -> &LocalRef<'tcx, V> {
+        &self.values[index]
+    }
+}
+
+/// To mutate locals, use `FunctionCx::overwrite_local` instead.
+impl<'tcx, V, Idx: ?Sized> !IndexMut<Idx> for Locals<'tcx, V> {}
+
+impl<'tcx, V> Locals<'tcx, V> {
+    pub(super) fn empty() -> Locals<'tcx, V> {
+        Locals { values: IndexVec::default() }
+    }
+
+    pub(super) fn indices(&self) -> impl DoubleEndedIterator<Item = mir::Local> + Clone + 'tcx {
+        self.values.indices()
+    }
+}
+
+impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+    pub(super) fn initialize_locals(&mut self, values: Vec<LocalRef<'tcx, Bx::Value>>) {
+        assert!(self.locals.values.is_empty());
+        // FIXME(#115215): After #115025 get's merged this might not be necessary
+        for (local, value) in values.into_iter().enumerate() {
+            match value {
+                LocalRef::Place(_) | LocalRef::UnsizedPlace(_) | LocalRef::PendingOperand => (),
+                LocalRef::Operand(op) => {
+                    let local = mir::Local::from_usize(local);
+                    let expected_ty = self.monomorphize(self.mir.local_decls[local].ty);
+                    if expected_ty != op.layout.ty {
+                        warn!("Unexpected initial operand type. See the issues/114858");
+                    }
+                }
+            }
+            self.locals.values.push(value);
+        }
+    }
+
+    pub(super) fn overwrite_local(
+        &mut self,
+        local: mir::Local,
+        mut value: LocalRef<'tcx, Bx::Value>,
+    ) {
+        match value {
+            LocalRef::Place(_) | LocalRef::UnsizedPlace(_) | LocalRef::PendingOperand => (),
+            LocalRef::Operand(ref mut op) => {
+                let local_ty = self.monomorphize(self.mir.local_decls[local].ty);
+                if local_ty != op.layout.ty {
+                    // FIXME(#112651): This can be changed to an ICE afterwards.
+                    debug!("updating type of operand due to subtyping");
+                    with_no_trimmed_paths!(debug!(?op.layout.ty));
+                    with_no_trimmed_paths!(debug!(?local_ty));
+                    op.layout.ty = local_ty;
+                }
+            }
+        };
+
+        self.locals.values[local] = value;
+    }
+}