Bug 720753 - hoist ToSourceCache from JSCompartment into JSRuntime (r=cdleary)

js/src/jscntxt.h

@@ -190,6 +190,20 @@ struct ConservativeGCData
     }
 };
 
+class ToSourceCache
+{
+    typedef HashMap<JSFunction *,
+                    JSString *,
+                    DefaultHasher<JSFunction *>,
+                    SystemAllocPolicy> Map;
+    Map *map_;
+  public:
+    ToSourceCache() : map_(NULL) {}
+    JSString *lookup(JSFunction *fun);
+    void put(JSFunction *fun, JSString *);
+    void purge();
+};
+
 class NativeIterCache
 {
     static const size_t SIZE = size_t(1) << 8;
@@ -740,6 +754,7 @@ struct JSRuntime : js::RuntimeFriendFields
     js::PropertyCache   propertyCache;
     js::NewObjectCache  newObjectCache;
     js::NativeIterCache nativeIterCache;
+    js::ToSourceCache   toSourceCache;
 
     /* State used by jsdtoa.cpp. */
     DtoaState           *dtoaState;

js/src/jscompartment.cpp

@@ -551,8 +551,6 @@ JSCompartment::purge()
             listHeadp = &script->evalHashLink();
         }
     }
-
-    toSourceCache.destroyIfConstructed();
 }
 
 void

js/src/jscompartment.h

@@ -58,11 +58,6 @@
 
 namespace js {
 
-typedef HashMap<JSFunction *,
-                JSString *,
-                DefaultHasher<JSFunction *>,
-                SystemAllocPolicy> ToSourceCache;
-
 /* Defined in jsapi.cpp */
 extern Class dummy_class;
 
@@ -272,9 +267,6 @@ struct JSCompartment
     unsigned                     debugModeBits;  // see debugMode() below
 
   public:
-    typedef js::Maybe<js::ToSourceCache> LazyToSourceCache;
-    LazyToSourceCache            toSourceCache;
-
     JSCompartment(JSRuntime *rt);
     ~JSCompartment();
 

js/src/jsfun.cpp

@@ -552,6 +552,36 @@ JS_FRIEND_DATA(Class) js::FunctionClass = {
     fun_trace
 };
 
+JSString *
+ToSourceCache::lookup(JSFunction *fun)
+{
+    if (!map_)
+        return NULL;
+    if (Map::Ptr p = map_->lookup(fun))
+        return p->value;
+    return NULL;
+}
+
+void
+ToSourceCache::put(JSFunction *fun, JSString *str)
+{
+    if (!map_) {
+        map_ = OffTheBooks::new_<Map>();
+        if (!map_)
+            return;
+        map_->init();
+    }
+
+    (void) map_->put(fun, str);
+}
+
+void
+ToSourceCache::purge()
+{
+    Foreground::delete_(map_);
+    map_ = NULL;
+}
+
 JSString *
 fun_toStringHelper(JSContext *cx, JSObject *obj, unsigned indent)
 {
@@ -569,28 +599,17 @@ fun_toStringHelper(JSContext *cx, JSObject *obj, unsigned indent)
     if (!fun)
         return NULL;
 
-    if (!indent && !cx->compartment->toSourceCache.empty()) {
-        ToSourceCache::Ptr p = cx->compartment->toSourceCache.ref().lookup(fun);
-        if (p)
-            return p->value;
+    if (!indent) {
+        if (JSString *str = cx->runtime->toSourceCache.lookup(fun))
+            return str;
     }
 
     JSString *str = JS_DecompileFunction(cx, fun, indent);
     if (!str)
         return NULL;
 
-    if (!indent) {
-        Maybe<ToSourceCache> &lazy = cx->compartment->toSourceCache;
-
-        if (lazy.empty()) {
-            lazy.construct();
-            if (!lazy.ref().init())
-                return NULL;
-        }
-
-        if (!lazy.ref().put(fun, str))
-            return NULL;
-    }
+    if (!indent)
+        cx->runtime->toSourceCache.put(fun, str);
 
     return str;
 }

js/src/jsgc.cpp

@@ -2892,6 +2892,7 @@ PurgeRuntime(JSTracer *trc)
     rt->propertyCache.purge(rt);
     rt->newObjectCache.purge();
     rt->nativeIterCache.purge();
+    rt->toSourceCache.purge();
 
     for (ContextIter acx(rt); !acx.done(); acx.next())
         acx->purge();