From 8fd7d49c9552108025e6d79cefd3c27c3d5d6f5a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Thu, 15 Feb 2018 10:52:26 +0100
Subject: [PATCH] Make HirMap thread-safe

---
 src/librustc/hir/map/mod.rs | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/librustc/hir/map/mod.rs b/src/librustc/hir/map/mod.rs
index e8bcbfbb77a1..1e348e3a31ce 100644
--- a/src/librustc/hir/map/mod.rs
+++ b/src/librustc/hir/map/mod.rs
@@ -33,10 +33,11 @@ use hir::svh::Svh;
 use util::nodemap::{DefIdMap, FxHashMap};
 
 use arena::TypedArena;
-use std::cell::RefCell;
 use std::io;
 use ty::TyCtxt;
 
+use rustc_data_structures::sync::Lock;
+
 pub mod blocks;
 mod collector;
 mod def_collector;
@@ -264,7 +265,7 @@ pub struct Map<'hir> {
     definitions: &'hir Definitions,
 
     /// Bodies inlined from other crates are cached here.
-    inlined_bodies: RefCell<DefIdMap<&'hir Body>>,
+    inlined_bodies: Lock<DefIdMap<&'hir Body>>,
 
     /// The reverse mapping of `node_to_hir_id`.
     hir_to_node_id: FxHashMap<HirId, NodeId>,
@@ -927,8 +928,13 @@ impl<'hir> Map<'hir> {
     }
 
     pub fn intern_inlined_body(&self, def_id: DefId, body: Body) -> &'hir Body {
+        let mut inlined_bodies = self.inlined_bodies.borrow_mut();
+        if let Some(&b) = inlined_bodies.get(&def_id) {
+            debug_assert_eq!(&body, b);
+            return b;
+        }
         let body = self.forest.inlined_bodies.alloc(body);
-        self.inlined_bodies.borrow_mut().insert(def_id, body);
+        inlined_bodies.insert(def_id, body);
         body
     }
 
@@ -1189,7 +1195,7 @@ pub fn map_crate<'hir>(sess: &::session::Session,
         map,
         hir_to_node_id,
         definitions,
-        inlined_bodies: RefCell::new(DefIdMap()),
+        inlined_bodies: Lock::new(DefIdMap()),
     };
 
     hir_id_validator::check_crate(&map);