Make building THIR a stealable query

compiler/rustc_interface/src/passes.rs

@@ -873,9 +873,8 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
 
     sess.time("MIR_effect_checking", || {
         for def_id in tcx.body_owners() {
-            if tcx.sess.opts.debugging_opts.thir_unsafeck {
-                tcx.ensure().thir_check_unsafety(def_id);
-            } else {
+            tcx.ensure().thir_check_unsafety(def_id);
+            if !tcx.sess.opts.debugging_opts.thir_unsafeck {
                 mir::transform::check_unsafety::check_unsafety(tcx, def_id);
             }
 

compiler/rustc_middle/src/arena.rs

@@ -14,6 +14,7 @@ macro_rules! arena_types {
             [] layouts: rustc_target::abi::Layout,
             // AdtDef are interned and compared by address
             [] adt_def: rustc_middle::ty::AdtDef,
+            [] steal_thir: rustc_data_structures::steal::Steal<rustc_middle::thir::Thir<$tcx>>,
             [] steal_mir: rustc_data_structures::steal::Steal<rustc_middle::mir::Body<$tcx>>,
             [decode] mir: rustc_middle::mir::Body<$tcx>,
             [] steal_promoted:

compiler/rustc_middle/src/dep_graph/dep_node.rs

@@ -285,7 +285,7 @@ pub type DepNode = rustc_query_system::dep_graph::DepNode<DepKind>;
 // required that their size stay the same, but we don't want to change
 // it inadvertently. This assert just ensures we're aware of any change.
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-static_assert_size!(DepNode, 17);
+static_assert_size!(DepNode, 18);
 
 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
 static_assert_size!(DepNode, 24);

compiler/rustc_middle/src/lib.rs

@@ -83,6 +83,7 @@ pub mod infer;
 pub mod lint;
 pub mod middle;
 pub mod mir;
+pub mod thir;
 pub mod traits;
 pub mod ty;
 

compiler/rustc_middle/src/query/mod.rs

@@ -220,6 +220,11 @@ rustc_queries! {
         desc { "checking if the crate is_panic_runtime" }
     }
 
+    /// Fetch the THIR for a given body. If typeck for that body failed, returns an empty `Thir`.
+    query thir_body(key: ty::WithOptConstParam<LocalDefId>) -> (&'tcx Steal<thir::Thir<'tcx>>, thir::ExprId) {
+        desc { |tcx| "building THIR for `{}`", tcx.def_path_str(key.did.to_def_id()) }
+    }
+
     /// Set of all the `DefId`s in this crate that have MIR associated with
     /// them. This includes all the body owners, but also things like struct
     /// constructors.