diff --git a/src/librustc/driver/driver.rs b/src/librustc/driver/driver.rs
index cda664213a5e..a095205e91bc 100644
--- a/src/librustc/driver/driver.rs
+++ b/src/librustc/driver/driver.rs
@@ -26,7 +26,7 @@ use middle;
 use util::common::time;
 use util::ppaux;
 
-use std::cell::RefCell;
+use std::cell::{Cell, RefCell};
 use std::hashmap::{HashMap,HashSet};
 use std::io;
 use std::io::fs;
@@ -874,8 +874,8 @@ pub fn build_session_(sopts: @session::options,
         parse_sess: p_s,
         codemap: cm,
         // For a library crate, this is always none
-        entry_fn: @mut None,
-        entry_type: @mut None,
+        entry_fn: RefCell::new(None),
+        entry_type: Cell::new(None),
         span_diagnostic: span_diagnostic_handler,
         filesearch: filesearch,
         building_library: @mut false,
diff --git a/src/librustc/driver/session.rs b/src/librustc/driver/session.rs
index 20ad6ce6a663..7052f5ea5fea 100644
--- a/src/librustc/driver/session.rs
+++ b/src/librustc/driver/session.rs
@@ -28,7 +28,7 @@ use syntax::abi;
 use syntax::parse::token;
 use syntax;
 
-use std::cell::RefCell;
+use std::cell::{Cell, RefCell};
 use std::hashmap::{HashMap,HashSet};
 
 pub struct config {
@@ -206,8 +206,8 @@ pub struct Session_ {
     parse_sess: @mut ParseSess,
     codemap: @codemap::CodeMap,
     // For a library crate, this is always none
-    entry_fn: @mut Option<(NodeId, codemap::Span)>,
-    entry_type: @mut Option<EntryFnType>,
+    entry_fn: RefCell<Option<(NodeId, codemap::Span)>>,
+    entry_type: Cell<Option<EntryFnType>>,
     span_diagnostic: @mut diagnostic::span_handler,
     filesearch: @filesearch::FileSearch,
     building_library: @mut bool,
diff --git a/src/librustc/middle/dead.rs b/src/librustc/middle/dead.rs
index b35068594805..aa58fc569a8d 100644
--- a/src/librustc/middle/dead.rs
+++ b/src/librustc/middle/dead.rs
@@ -212,7 +212,7 @@ fn create_and_seed_worklist(tcx: ty::ctxt,
     }
 
     // Seed entry point
-    match *tcx.sess.entry_fn {
+    match tcx.sess.entry_fn.get() {
         Some((id, _)) => worklist.push(id),
         None => ()
     }
diff --git a/src/librustc/middle/entry.rs b/src/librustc/middle/entry.rs
index 4103812d3618..0c50eb294d50 100644
--- a/src/librustc/middle/entry.rs
+++ b/src/librustc/middle/entry.rs
@@ -52,7 +52,7 @@ pub fn find_entry_point(session: Session, crate: &Crate, ast_map: ast_map::map)
 
     // If the user wants no main function at all, then stop here.
     if attr::contains_name(crate.attrs, "no_main") {
-        *session.entry_type = Some(session::EntryNone);
+        session.entry_type.set(Some(session::EntryNone));
         return
     }
 
@@ -122,14 +122,14 @@ fn find_item(item: @item, ctxt: &mut EntryContext) {
 
 fn configure_main(this: &mut EntryContext) {
     if this.start_fn.is_some() {
-        *this.session.entry_fn = this.start_fn;
-        *this.session.entry_type = Some(session::EntryStart);
+        this.session.entry_fn.set(this.start_fn);
+        this.session.entry_type.set(Some(session::EntryStart));
     } else if this.attr_main_fn.is_some() {
-        *this.session.entry_fn = this.attr_main_fn;
-        *this.session.entry_type = Some(session::EntryMain);
+        this.session.entry_fn.set(this.attr_main_fn);
+        this.session.entry_type.set(Some(session::EntryMain));
     } else if this.main_fn.is_some() {
-        *this.session.entry_fn = this.main_fn;
-        *this.session.entry_type = Some(session::EntryMain);
+        this.session.entry_fn.set(this.main_fn);
+        this.session.entry_type.set(Some(session::EntryMain));
     } else {
         if !*this.session.building_library {
             // No main function
diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs
index 104d8f24a368..ac4ce95ae42d 100644
--- a/src/librustc/middle/trans/base.rs
+++ b/src/librustc/middle/trans/base.rs
@@ -2382,7 +2382,7 @@ pub fn register_fn_llvmty(ccx: @CrateContext,
 }
 
 pub fn is_entry_fn(sess: &Session, node_id: ast::NodeId) -> bool {
-    match *sess.entry_fn {
+    match sess.entry_fn.get() {
         Some((entry_id, _)) => node_id == entry_id,
         None => false
     }
@@ -2393,7 +2393,7 @@ pub fn is_entry_fn(sess: &Session, node_id: ast::NodeId) -> bool {
 pub fn create_entry_wrapper(ccx: @CrateContext,
                            _sp: Span,
                            main_llfn: ValueRef) {
-    let et = ccx.sess.entry_type.unwrap();
+    let et = ccx.sess.entry_type.get().unwrap();
     match et {
         session::EntryMain => {
             create_entry_fn(ccx, main_llfn, true);
diff --git a/src/librustc/middle/typeck/mod.rs b/src/librustc/middle/typeck/mod.rs
index 176bf72d8a40..4443fa000e71 100644
--- a/src/librustc/middle/typeck/mod.rs
+++ b/src/librustc/middle/typeck/mod.rs
@@ -439,8 +439,8 @@ fn check_start_fn_ty(ccx: &CrateCtxt,
 fn check_for_entry_fn(ccx: &CrateCtxt) {
     let tcx = ccx.tcx;
     if !*tcx.sess.building_library {
-        match *tcx.sess.entry_fn {
-          Some((id, sp)) => match *tcx.sess.entry_type {
+        match tcx.sess.entry_fn.get() {
+          Some((id, sp)) => match tcx.sess.entry_type.get() {
               Some(session::EntryMain) => check_main_fn_ty(ccx, id, sp),
               Some(session::EntryStart) => check_start_fn_ty(ccx, id, sp),
               Some(session::EntryNone) => {}