1 files changed, 32 insertions, 0 deletions
diff --git a/compiler/rustc_smir/src/rustc_internal/mod.rs b/compiler/rustc_smir/src/rustc_internal/mod.rs
new file mode 100644
index 000000000..5998c8b65
--- /dev/null
+++ b/compiler/rustc_smir/src/rustc_internal/mod.rs
@@ -0,0 +1,32 @@
+//! Module that implements the bridge between Stable MIR and internal compiler MIR.
+//!
+//! For that, we define APIs that will temporarily be public to 3P that exposes rustc internal APIs
+//! until stable MIR is complete.
+
+use std::sync::RwLock;
+
+use crate::stable_mir;
+pub use rustc_span::def_id::{CrateNum, DefId};
+
+static DEF_ID_MAP: RwLock<Vec<DefId>> = RwLock::new(Vec::new());
+
+pub fn item_def_id(item: &stable_mir::CrateItem) -> DefId {
+    DEF_ID_MAP.read().unwrap()[item.0]
+}
+
+pub fn crate_item(did: DefId) -> stable_mir::CrateItem {
+    // FIXME: this becomes inefficient when we have too many ids
+    let mut map = DEF_ID_MAP.write().unwrap();
+    for (i, &d) in map.iter().enumerate() {
+        if d == did {
+            return stable_mir::CrateItem(i);
+        }
+    }
+    let id = map.len();
+    map.push(did);
+    stable_mir::CrateItem(id)
+}
+
+pub fn crate_num(item: &stable_mir::Crate) -> CrateNum {
+    item.id.into()
+}