Bug 1358135 part 2 - Preserve a Zone's JIT code also when it has Baseline code on the stack. r=bhackett

js/src/jit-test/tests/self-test/inIon.js

@@ -13,7 +13,7 @@ function test() {
     while(!callInIon());
 
     // Test with zealous gc preventing compilation.
-    while(!inIon()) gc();
+    while(!inIon()) gc(this, 'shrinking');
 };
 
 test();

js/src/jit/JitFrames.cpp

@@ -1532,19 +1532,8 @@ TraceJitActivations(JSContext* cx, const CooperatingContext& target, JSTracer* t
         TraceJitActivation(trc, activations);
 }
 
-JSCompartment*
-TopmostIonActivationCompartment(JSContext* cx)
-{
-    for (JitActivationIterator activations(cx); !activations.done(); ++activations) {
-        for (JitFrameIterator frames(activations); !frames.done(); ++frames) {
-            if (frames.type() == JitFrame_IonJS)
-                return activations.activation()->compartment();
-        }
-    }
-    return nullptr;
-}
-
-void UpdateJitActivationsForMinorGC(JSRuntime* rt, JSTracer* trc)
+void
+UpdateJitActivationsForMinorGC(JSRuntime* rt, JSTracer* trc)
 {
     MOZ_ASSERT(JS::CurrentThreadIsHeapMinorCollecting());
     JSContext* cx = TlsContext.get();

js/src/jit/JitFrames.h

@@ -287,9 +287,6 @@ void EnsureBareExitFrame(JSContext* cx, JitFrameLayout* frame);
 
 void TraceJitActivations(JSContext* cx, const CooperatingContext& target, JSTracer* trc);
 
-JSCompartment*
-TopmostIonActivationCompartment(JSContext* cx);
-
 void UpdateJitActivationsForMinorGC(JSRuntime* rt, JSTracer* trc);
 
 static inline uint32_t

js/src/jsgc.cpp

@@ -3850,8 +3850,9 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
     }
 
     if (!rt->gc.cleanUpEverything && canAllocateMoreCode) {
-        if (JSCompartment* comp = jit::TopmostIonActivationCompartment(TlsContext.get()))
-            comp->zone()->setPreservingCode(true);
+        jit::JitActivationIterator activation(TlsContext.get());
+        if (!activation.done())
+            activation->compartment()->zone()->setPreservingCode(true);
     }
 
     /*