Bug 984537 - Keep JIT code around for compartments on the stack when triggering GC, r=jandem.

js/src/jit/IonFrames.cpp

@@ -1221,6 +1221,14 @@ MarkJitActivations(JSRuntime *rt, JSTracer *trc)
         MarkJitActivation(trc, activations);
 }
 
+JSCompartment *
+TopmostJitActivationCompartment(JSRuntime *rt)
+{
+    for (JitActivationIterator activations(rt); !activations.done(); ++activations)
+        return activations.activation()->compartment();
+    return nullptr;
+}
+
 #ifdef JSGC_GENERATIONAL
 void
 UpdateJitActivationsForMinorGC(JSRuntime *rt, JSTracer *trc)

js/src/jit/IonFrames.h

@@ -268,6 +268,9 @@ void EnsureExitFrame(IonCommonFrameLayout *frame);
 void MarkJitActivations(JSRuntime *rt, JSTracer *trc);
 void MarkIonCompilerRoots(JSTracer *trc);
 
+JSCompartment *
+TopmostJitActivationCompartment(JSRuntime *rt);
+
 #ifdef JSGC_GENERATIONAL
 void UpdateJitActivationsForMinorGC(JSRuntime *rt, JSTracer *trc);
 #endif

js/src/jsgc.cpp

@@ -2770,6 +2770,11 @@ BeginMarkPhase(JSRuntime *rt)
             c->zone()->setPreservingCode(true);
     }
 
+    if (!rt->gcShouldCleanUpEverything) {
+        if (JSCompartment *comp = jit::TopmostJitActivationCompartment(rt))
+            comp->zone()->setPreservingCode(true);
+    }
+
     /*
      * Atoms are not in the cross-compartment map. So if there are any
      * zones that are not being collected, we are not allowed to collect