Add `-Z unpretty` flag for the THIR

Cargo.lock

@@ -3870,6 +3870,7 @@ dependencies = [
  "rustc_metadata",
  "rustc_middle",
  "rustc_mir",
+ "rustc_mir_build",
  "rustc_parse",
  "rustc_plugin_impl",
  "rustc_save_analysis",
@@ -3877,6 +3878,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
+ "rustc_typeck",
  "tracing",
  "tracing-subscriber",
  "tracing-tree",

compiler/rustc_driver/Cargo.toml

@@ -34,6 +34,8 @@ rustc_interface = { path = "../rustc_interface" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_span = { path = "../rustc_span" }
+rustc_mir_build = { path = "../rustc_mir_build" }
+rustc_typeck = { path = "../rustc_typeck" }
 
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["consoleapi", "debugapi", "processenv"] }

compiler/rustc_driver/src/pretty.rs

@@ -9,12 +9,14 @@ use rustc_hir_pretty as pprust_hir;
 use rustc_middle::hir::map as hir_map;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_mir::util::{write_mir_graphviz, write_mir_pretty};
+use rustc_mir_build::thir;
 use rustc_session::config::{Input, PpAstTreeMode, PpHirMode, PpMode, PpSourceMode};
 use rustc_session::Session;
 use rustc_span::symbol::Ident;
 use rustc_span::FileName;
 
 use std::cell::Cell;
+use std::fmt::Write;
 use std::path::Path;
 
 pub use self::PpMode::*;
@@ -469,6 +471,21 @@ pub fn print_after_hir_lowering<'tcx>(
             format!("{:#?}", krate)
         }),
 
+        ThirTree => {
+            let mut out = String::new();
+            abort_on_err(rustc_typeck::check_crate(tcx), tcx.sess);
+            debug!("pretty printing THIR tree");
+            for did in tcx.body_owners() {
+                let hir = tcx.hir();
+                let body = hir.body(hir.body_owned_by(hir.local_def_id_to_hir_id(did)));
+                let arena = thir::Arena::default();
+                let thir =
+                    thir::build_thir(tcx, ty::WithOptConstParam::unknown(did), &arena, &body.value);
+                let _ = writeln!(out, "{:?}:\n{:#?}\n", did, thir);
+            }
+            out
+        }
+
         _ => unreachable!(),
     };
 

compiler/rustc_session/src/config.rs

@@ -2074,6 +2074,7 @@ fn parse_pretty(
             ("hir,identified", true) => Hir(PpHirMode::Identified),
             ("hir,typed", true) => Hir(PpHirMode::Typed),
             ("hir-tree", true) => HirTree,
+            ("thir-tree", true) => ThirTree,
             ("mir", true) => Mir,
             ("mir-cfg", true) => MirCFG,
             _ => {
@@ -2265,6 +2266,8 @@ pub enum PpMode {
     Hir(PpHirMode),
     /// `-Zunpretty=hir-tree`
     HirTree,
+    /// `-Zunpretty=thir-tree`
+    ThirTree,
     /// `-Zunpretty=mir`
     Mir,
     /// `-Zunpretty=mir-cfg`
@@ -2282,6 +2285,7 @@ impl PpMode {
             | AstTree(PpAstTreeMode::Expanded)
             | Hir(_)
             | HirTree
+            | ThirTree
             | Mir
             | MirCFG => true,
         }