Bug 1149352 - Part 0: Only mark live entries when marking a range; r=meow

js/src/gc/Marking.cpp

@@ -431,19 +431,23 @@ js::TraceRoot(JSTracer* trc, T* thingp, const char* name)
 
 template <typename T>
 void
-js::TraceRange(JSTracer* trc, size_t len, BarrieredBase<T>* thingp, const char* name)
+js::TraceRange(JSTracer* trc, size_t len, BarrieredBase<T>* vec, const char* name)
 {
-    for (auto i : MakeRange(len))
-        DispatchToTracer(trc, ConvertToBase(thingp[i].unsafeGet()), name, i);
+    for (auto i : MakeRange(len)) {
+        if (InternalGCMethods<T>::isMarkable(vec[i].get()))
+            DispatchToTracer(trc, ConvertToBase(vec[i].unsafeGet()), name, i);
+    }
 }
 
 template <typename T>
 void
-js::TraceRootRange(JSTracer* trc, size_t len, T* thingp, const char* name)
+js::TraceRootRange(JSTracer* trc, size_t len, T* vec, const char* name)
 {
     JS_ROOT_MARKING_ASSERT(trc);
-    for (auto i : MakeRange(len))
-        DispatchToTracer(trc, ConvertToBase(&thingp[i]), name, i);
+    for (auto i : MakeRange(len)) {
+        if (InternalGCMethods<T>::isMarkable(vec[i]))
+            DispatchToTracer(trc, ConvertToBase(&vec[i]), name, i);
+    }
 }
 
 // Instantiate a copy of the Tracing templates for each derived type.

js/src/gc/Marking.h

@@ -62,12 +62,12 @@ TraceManuallyBarrieredEdge(JSTracer* trc, T* thingp, const char* name);
 // Trace all edges contained in the given array.
 template <typename T>
 void
-TraceRange(JSTracer* trc, size_t len, BarrieredBase<T>* thingp, const char* name);
+TraceRange(JSTracer* trc, size_t len, BarrieredBase<T>* vec, const char* name);
 
 // Trace all root edges in the given array.
 template <typename T>
 void
-TraceRootRange(JSTracer* trc, size_t len, T* thingp, const char* name);
+TraceRootRange(JSTracer* trc, size_t len, T* vec, const char* name);
 
 // Trace an edge that crosses compartment boundaries. If the compartment of the
 // destination thing is not being GC'd, then the edge will not be traced.