Implement SmirInterface

 - With `Context` wrapped by `SmirInterface`, the stable-mir's TLV stores a pointer to `SmirInterface`, while the rustc-specific TLV stores a pointer to tables.
 - This PR make the `rustc_smir` mod public.

Author: makai410

compiler/rustc_smir/src/lib.rs

@@ -20,7 +20,6 @@
 
 pub mod rustc_internal;
 
-// Make this module private for now since external users should not call these directly.
-mod rustc_smir;
+pub mod rustc_smir;
 
 pub mod stable_mir;

compiler/rustc_smir/src/rustc_internal/mod.rs

@@ -18,9 +18,10 @@ use rustc_span::def_id::{CrateNum, DefId};
 use scoped_tls::scoped_thread_local;
 use stable_mir::Error;
 use stable_mir::abi::Layout;
+use stable_mir::compiler_interface::SmirInterface;
 use stable_mir::ty::IndexedVal;
 
-use crate::rustc_smir::context::TablesWrapper;
+use crate::rustc_smir::context::Context;
 use crate::rustc_smir::{Stable, Tables};
 use crate::stable_mir;
 
@@ -196,12 +197,12 @@ pub fn crate_num(item: &stable_mir::Crate) -> CrateNum {
 // datastructures and stable MIR datastructures
 scoped_thread_local! (static TLV: Cell<*const ()>);
 
-pub(crate) fn init<'tcx, F, T>(tables: &TablesWrapper<'tcx>, f: F) -> T
+pub(crate) fn init<'tcx, F, T>(cx: &Context<'tcx>, f: F) -> T
 where
     F: FnOnce() -> T,
 {
     assert!(!TLV.is_set());
-    let ptr = tables as *const _ as *const ();
+    let ptr = cx as *const _ as *const ();
     TLV.set(&Cell::new(ptr), || f())
 }
 
@@ -212,8 +213,8 @@ pub(crate) fn with_tables<R>(f: impl for<'tcx> FnOnce(&mut Tables<'tcx>) -> R) -
     TLV.with(|tlv| {
         let ptr = tlv.get();
         assert!(!ptr.is_null());
-        let wrapper = ptr as *const TablesWrapper<'_>;
-        let mut tables = unsafe { (*wrapper).0.borrow_mut() };
+        let context = ptr as *const Context<'_>;
+        let mut tables = unsafe { (*context).0.borrow_mut() };
         f(&mut *tables)
     })
 }
@@ -222,7 +223,7 @@ pub fn run<F, T>(tcx: TyCtxt<'_>, f: F) -> Result<T, Error>
 where
     F: FnOnce() -> T,
 {
-    let tables = TablesWrapper(RefCell::new(Tables {
+    let tables = Context(RefCell::new(Tables {
         tcx,
         def_ids: IndexMap::default(),
         alloc_ids: IndexMap::default(),
@@ -233,7 +234,12 @@ where
         mir_consts: IndexMap::default(),
         layouts: IndexMap::default(),
     }));
-    stable_mir::compiler_interface::run(&tables, || init(&tables, f))
+
+    let interface = SmirInterface { cx: tables };
+
+    // Pass the `SmirInterface` to compiler_interface::run
+    // and initialize the rustc-specific TLS with tables.
+    stable_mir::compiler_interface::run(&interface, || init(&interface.cx, f))
 }
 
 /// Instantiate and run the compiler with the provided arguments and callback.