From fe636373505b610447b952200d91ae2708ce5947 Mon Sep 17 00:00:00 2001
From: =?utf8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Fri, 13 Apr 2018 19:33:31 +0200
Subject: [PATCH] Use locks for Session.lint_store and Session.buffered_lints

---
 src/librustc/lint/context.rs |  8 ++++----
 src/librustc/session/mod.rs  | 10 +++++-----
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/librustc/lint/context.rs b/src/librustc/lint/context.rs
index 9f8cc2f8699..d5849ea22b1 100644
--- a/src/librustc/lint/context.rs
+++ b/src/librustc/lint/context.rs
@@ -27,6 +27,7 @@
 use self::TargetLint::*;
 
 use std::slice;
+use rustc_data_structures::sync::{RwLock, ReadGuard};
 use lint::{EarlyLintPassObject, LateLintPassObject};
 use lint::{Level, Lint, LintId, LintPass, LintBuffer};
 use lint::builtin::BuiltinLintDiagnostics;
@@ -39,7 +40,6 @@
 use util::nodemap::FxHashMap;
 
 use std::default::Default as StdDefault;
-use std::cell::{Ref, RefCell};
 use syntax::ast;
 use syntax::edition;
 use syntax_pos::{MultiSpan, Span};
@@ -78,7 +78,7 @@ pub struct LintStore {
 
 pub struct LintSession<'a, PassObject> {
     /// Reference to the store of registered lints.
-    lints: Ref<'a, LintStore>,
+    lints: ReadGuard<'a, LintStore>,
 
     /// Trait objects for each lint pass.
     passes: Option<Vec<PassObject>>,
@@ -336,7 +336,7 @@ impl<'a, PassObject: LintPassObject> LintSession<'a, PassObject> {
     /// Creates a new `LintSession`, by moving out the `LintStore`'s initial
     /// lint levels and pass objects. These can be restored using the `restore`
     /// method.
-    fn new(store: &'a RefCell<LintStore>) -> LintSession<'a, PassObject> {
+    fn new(store: &'a RwLock<LintStore>) -> LintSession<'a, PassObject> {
         let mut s = store.borrow_mut();
         let passes = PassObject::take_passes(&mut *s);
         drop(s);
@@ -347,7 +347,7 @@ fn new(store: &'a RefCell<LintStore>) -> LintSession<'a, PassObject> {
     }
 
     /// Restores the levels back to the original lint store.
-    fn restore(self, store: &RefCell<LintStore>) {
+    fn restore(self, store: &RwLock<LintStore>) {
         drop(self.lints);
         let mut s = store.borrow_mut();
         PassObject::restore_passes(&mut *s, self.passes);
diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index 8f2043fdfc6..77dff0950ee 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -26,7 +26,7 @@
 use util::common::{duration_to_secs_str, ErrorReported};
 use util::common::ProfileQueriesMsg;
 
-use rustc_data_structures::sync::{Lrc, Lock, LockCell, OneThread, Once};
+use rustc_data_structures::sync::{Lrc, Lock, LockCell, OneThread, Once, RwLock};
 
 use syntax::ast::NodeId;
 use errors::{self, DiagnosticBuilder, DiagnosticId};
@@ -83,8 +83,8 @@ pub struct Session {
 
     // FIXME: lint_store and buffered_lints are not thread-safe,
     // but are only used in a single thread
-    pub lint_store: OneThread<RefCell<lint::LintStore>>,
-    pub buffered_lints: OneThread<RefCell<Option<lint::LintBuffer>>>,
+    pub lint_store: RwLock<lint::LintStore>,
+    pub buffered_lints: Lock<Option<lint::LintBuffer>>,
 
     /// Set of (DiagnosticId, Option<Span>, message) tuples tracking
     /// (sub)diagnostics that have been set once, but should not be set again,
@@ -1091,8 +1091,8 @@ pub fn build_session_(
         default_sysroot,
         local_crate_source_file,
         working_dir,
-        lint_store: OneThread::new(RefCell::new(lint::LintStore::new())),
-        buffered_lints: OneThread::new(RefCell::new(Some(lint::LintBuffer::new()))),
+        lint_store: RwLock::new(lint::LintStore::new()),
+        buffered_lints: Lock::new(Some(lint::LintBuffer::new())),
         one_time_diagnostics: RefCell::new(FxHashSet()),
         plugin_llvm_passes: OneThread::new(RefCell::new(Vec::new())),
         plugin_attributes: OneThread::new(RefCell::new(Vec::new())),
-- 
2.44.0