Output tree representation on thir-tree

compiler/rustc_driver/src/pretty.rs

@@ -498,6 +498,21 @@ fn print_with_analysis(tcx: TyCtxt<'_>, ppm: PpMode) -> Result<(), ErrorGuarante
             out
         }
 
+        ThirFlat => {
+            let mut out = String::new();
+            abort_on_err(rustc_hir_analysis::check_crate(tcx), tcx.sess);
+            debug!("pretty printing THIR flat");
+            for did in tcx.hir().body_owners() {
+                let _ = writeln!(
+                    out,
+                    "{:?}:\n{}\n",
+                    did,
+                    tcx.thir_flat(ty::WithOptConstParam::unknown(did))
+                );
+            }
+            out
+        }
+
         _ => unreachable!(),
     };
 

compiler/rustc_middle/src/query/mod.rs

@@ -361,6 +361,13 @@ rustc_queries! {
         desc { |tcx| "constructing THIR tree for `{}`", tcx.def_path_str(key.did.to_def_id()) }
     }
 
+    /// Create a list-like THIR representation for debugging.
+    query thir_flat(key: ty::WithOptConstParam<LocalDefId>) -> String {
+        no_hash
+        arena_cache
+        desc { |tcx| "constructing flat THIR representation 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.

compiler/rustc_middle/src/thir.rs

@@ -29,6 +29,7 @@ use rustc_target::asm::InlineAsmRegOrRegClass;
 use std::fmt;
 use std::ops::Index;
 
+pub mod print;
 pub mod visit;
 
 macro_rules! thir_with_elements {