[tbb-commits] [tor-browser/esr24] Bug 986843 - Replace AutoHoldZone with AutoCompartmentRooter. r=terrence, a=lsblakk

[mikeperry at torproject.org]

commit dcaf26b42bbfbb61c7ed1df992c3919052fa82a9
Author: Jon Coppeard <jcoppeard at mozilla.com>
Date:   Mon Mar 24 21:45:23 2014 +0000

    Bug 986843 - Replace AutoHoldZone with AutoCompartmentRooter. r=terrence, a=lsblakk
---
 js/src/gc/RootMarking.cpp |    2 +-
 js/src/gc/Zone.cpp        |   11 ++++++++++-
 js/src/gc/Zone.h          |    4 ++--
 js/src/jsapi.cpp          |   29 ++++++++++++++++++-----------
 js/src/jscompartment.cpp  |    2 +-
 js/src/jscompartment.h    |    2 +-
 js/src/jsgc.cpp           |    8 +++++---
 7 files changed, 38 insertions(+), 20 deletions(-)

diff --git a/js/src/gc/RootMarking.cpp b/js/src/gc/RootMarking.cpp
index 861c2d6..88574f3 100644
--- a/js/src/gc/RootMarking.cpp
+++ b/js/src/gc/RootMarking.cpp
@@ -744,7 +744,7 @@ js::gc::MarkRuntime(JSTracer *trc, bool useSavedRoots)
 #endif
 
     for (CompartmentsIter c(rt); !c.done(); c.next())
-        c->mark(trc);
+        c->markRoots(trc);
 
     /* The embedding can register additional roots here. */
     for (size_t i = 0; i < rt->gcBlackRootTracers.length(); i++) {
diff --git a/js/src/gc/Zone.cpp b/js/src/gc/Zone.cpp
index 5625b99..e1f0147 100644
--- a/js/src/gc/Zone.cpp
+++ b/js/src/gc/Zone.cpp
@@ -23,7 +23,6 @@ using namespace js::gc;
 JS::Zone::Zone(JSRuntime *rt)
   : rt(rt),
     allocator(this),
-    hold(false),
     ionUsingBarriers_(false),
     active(false),
     gcScheduled(false),
@@ -227,3 +226,13 @@ Zone::discardJitCode(FreeOp *fop, bool discardConstraints)
     }
 #endif
 }
+
+bool
+Zone::hasMarkedCompartments()
+{
+    for (CompartmentsInZoneIter comp(this); !comp.done(); comp.next()) {
+        if (comp->marked)
+            return true;
+    }
+    return false;
+}
diff --git a/js/src/gc/Zone.h b/js/src/gc/Zone.h
index 73e7043..d740306 100644
--- a/js/src/gc/Zone.h
+++ b/js/src/gc/Zone.h
@@ -108,8 +108,6 @@ struct Zone : private JS::shadow::Zone,
 
     js::CompartmentVector        compartments;
 
-    bool                         hold;
-
   private:
     bool                         ionUsingBarriers_;
 
@@ -300,6 +298,8 @@ struct Zone : private JS::shadow::Zone,
 
     void sweep(js::FreeOp *fop, bool releaseTypes);
 
+    bool hasMarkedCompartments();
+
   private:
     void sweepBreakpoints(js::FreeOp *fop);
 };
diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index 3632a74..68b6afa 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -3171,23 +3171,32 @@ JS_GetObjectId(JSContext *cx, JSObject *obj, jsid *idp)
     return JS_TRUE;
 }
 
-class AutoHoldZone
+class AutoCompartmentRooter : private JS::CustomAutoRooter
 {
   public:
-    explicit AutoHoldZone(Zone *zone
-                          MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
-      : holdp(&zone->hold)
+    explicit AutoCompartmentRooter(JSContext *cx, JSCompartment *comp
+                                   MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+      : CustomAutoRooter(cx), compartment(comp)
     {
         MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-        *holdp = true;
     }
 
-    ~AutoHoldZone() {
-        *holdp = false;
+    operator JSCompartment *() {
+        return compartment;
+    }
+
+    JSCompartment *operator->() {
+        return compartment;
+    }
+
+  protected:
+    virtual void trace(JSTracer *trc)
+    {
+        compartment->mark();
     }
 
   private:
-    bool *holdp;
+    JSCompartment *compartment;
     MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 };
 
@@ -3209,7 +3218,7 @@ JS_NewGlobalObject(JSContext *cx, JSClass *clasp, JSPrincipals *principals,
     else
         zone = ((JSObject *)options.zoneSpec)->zone();
 
-    JSCompartment *compartment = NewCompartment(cx, zone, principals, options);
+    AutoCompartmentRooter compartment(cx, NewCompartment(cx, zone, principals, options));
     if (!compartment)
         return NULL;
 
@@ -3218,8 +3227,6 @@ JS_NewGlobalObject(JSContext *cx, JSClass *clasp, JSPrincipals *principals,
         rt->systemZone->isSystem = true;
     }
 
-    AutoHoldZone hold(compartment->zone());
-
     Rooted<GlobalObject *> global(cx);
     {
         AutoCompartment ac(cx, compartment);
diff --git a/js/src/jscompartment.cpp b/js/src/jscompartment.cpp
index c448e10..2e66253 100644
--- a/js/src/jscompartment.cpp
+++ b/js/src/jscompartment.cpp
@@ -488,7 +488,7 @@ JSCompartment::markAllCrossCompartmentWrappers(JSTracer *trc)
 }
 
 void
-JSCompartment::mark(JSTracer *trc)
+JSCompartment::markRoots(JSTracer *trc)
 {
 #ifdef JS_ION
     if (ionCompartment_)
diff --git a/js/src/jscompartment.h b/js/src/jscompartment.h
index 6cc1bc8..1ef2ed8 100644
--- a/js/src/jscompartment.h
+++ b/js/src/jscompartment.h
@@ -293,7 +293,7 @@ struct JSCompartment
         WrapperEnum(JSCompartment *c) : js::WrapperMap::Enum(c->crossCompartmentWrappers) {}
     };
 
-    void mark(JSTracer *trc);
+    void markRoots(JSTracer *trc);
     bool isDiscardingJitCode(JSTracer *trc);
     void sweep(js::FreeOp *fop, bool releaseTypes);
     void sweepCrossCompartmentWrappers();
diff --git a/js/src/jsgc.cpp b/js/src/jsgc.cpp
index 53a636e..0db550f 100644
--- a/js/src/jsgc.cpp
+++ b/js/src/jsgc.cpp
@@ -2541,8 +2541,10 @@ SweepZones(FreeOp *fop, bool lastGC)
     while (read < end) {
         Zone *zone = *read++;
 
-        if (!zone->hold && zone->wasGCStarted()) {
-            if (zone->allocator.arenas.arenaListsAreEmpty() || lastGC) {
+        if (zone->wasGCStarted()) {
+            if ((zone->allocator.arenas.arenaListsAreEmpty() && !zone->hasMarkedCompartments()) ||
+                lastGC)
+            {
                 zone->allocator.arenas.checkEmptyFreeLists();
                 if (callback)
                     callback(zone);
@@ -2723,7 +2725,7 @@ BeginMarkPhase(JSRuntime *rt)
         }
 
         zone->scheduledForDestruction = false;
-        zone->maybeAlive = zone->hold;
+        zone->maybeAlive = false;
         zone->setPreservingCode(false);
     }