Bug 753615 - Ensure we don't re-enter a GC phase (r=terrence)

js/src/gc/Statistics.cpp

@@ -599,6 +599,9 @@ Statistics::endSlice()
 void
 Statistics::beginPhase(Phase phase)
 {
+    /* Guard against re-entry */
+    JS_ASSERT(!phaseStartTimes[phase]);
+
     phaseStartTimes[phase] = PRMJ_Now();
     phaseStartFaults[phase] = gc::GetPageFaultCount();
 
@@ -614,6 +617,7 @@ Statistics::endPhase(Phase phase)
     int64_t t = PRMJ_Now() - phaseStartTimes[phase];
     slices.back().phaseTimes[phase] += t;
     phaseTimes[phase] += t;
+    phaseStartTimes[phase] = 0;
 
     size_t faults = gc::GetPageFaultCount() - phaseStartFaults[phase];
     slices.back().phaseFaults[phase] += faults;

js/src/jsgc.cpp

@@ -3449,7 +3449,6 @@ IncrementalMarkSlice(JSRuntime *rt, int64_t budget, JSGCInvocationKind gckind, b
 
     *shouldSweep = false;
     if (rt->gcIncrementalState == MARK) {
-        gcstats::AutoPhase ap(rt->gcStats, gcstats::PHASE_MARK);
         SliceBudget sliceBudget(budget);
 
         /* If we needed delayed marking for gray roots, then collect until done. */
@@ -3466,7 +3465,11 @@ IncrementalMarkSlice(JSRuntime *rt, int64_t budget, JSGCInvocationKind gckind, b
         }
 #endif
 
-        bool finished = rt->gcMarker.drainMarkStack(sliceBudget);
+        bool finished;
+        {
+            gcstats::AutoPhase ap(rt->gcStats, gcstats::PHASE_MARK);
+            finished = rt->gcMarker.drainMarkStack(sliceBudget);
+        }
         if (finished) {
             JS_ASSERT(rt->gcMarker.isDrained());
             if (initialState == MARK && !rt->gcLastMarkSlice && budget != SliceBudget::Unlimited) {