Bug 1464134 part 1 - Fix various places to use Realm instead of JSCompartment. r=luke

js/src/fuzz-tests/tests.cpp

@@ -87,12 +87,8 @@ jsfuzz_init(JSContext** cx, JS::PersistentRootedObject* global)
 }
 
 static void
-jsfuzz_uninit(JSContext* cx, JSCompartment* oldCompartment)
+jsfuzz_uninit(JSContext* cx)
 {
-    if (oldCompartment) {
-        JS::LeaveRealm(cx, JS::GetRealmForCompartment(oldCompartment));
-        oldCompartment = nullptr;
-    }
     if (cx) {
         JS_EndRequest(cx);
         JS_DestroyContext(cx);
@@ -143,7 +139,7 @@ main(int argc, char* argv[])
     testingFunc(nullptr, 0);
 #endif
 
-    jsfuzz_uninit(gCx, nullptr);
+    jsfuzz_uninit(gCx);
 
     JS_ShutDown();
 

js/src/gc/GC.cpp

@@ -7914,9 +7914,8 @@ AutoPrepareForTracing::AutoPrepareForTracing(JSContext* cx)
     session_.emplace(cx->runtime());
 }
 
-JSCompartment*
+Realm*
-js::NewCompartment(JSContext* cx, JSPrincipals* principals,
+js::NewRealm(JSContext* cx, JSPrincipals* principals, const JS::RealmOptions& options)
-                   const JS::RealmOptions& options)
 {
     JSRuntime* rt = cx->runtime();
     JS_AbortIfWrongThread(cx);
@@ -7983,30 +7982,28 @@ js::NewCompartment(JSContext* cx, JSPrincipals* principals,
     }
 
     zoneHolder.forget();
-    return JS::GetCompartmentForRealm(realm.forget());
+    return realm.forget();
 }
 
 void
-gc::MergeCompartments(JSCompartment* source, JSCompartment* target)
+gc::MergeRealms(Realm* source, Realm* target)
 {
     JSRuntime* rt = source->runtimeFromMainThread();
-    rt->gc.mergeCompartments(source, target);
+    rt->gc.mergeRealms(source, target);
 
     AutoLockGC lock(rt);
     rt->gc.maybeAllocTriggerZoneGC(target->zone(), lock);
 }
 
 void
-GCRuntime::mergeCompartments(JSCompartment* source, JSCompartment* target)
+GCRuntime::mergeRealms(Realm* source, Realm* target)
 {
     // The source realm must be specifically flagged as mergable.  This
     // also implies that the realm is not visible to the debugger.
-    Realm* sourceRealm = JS::GetRealmForCompartment(source);
+    MOZ_ASSERT(source->creationOptions().mergeable());
-    Realm* targetRealm = JS::GetRealmForCompartment(target);
+    MOZ_ASSERT(source->creationOptions().invisibleToDebugger());
-    MOZ_ASSERT(sourceRealm->creationOptions().mergeable());
-    MOZ_ASSERT(sourceRealm->creationOptions().invisibleToDebugger());
 
-    MOZ_ASSERT(!sourceRealm->hasBeenEntered());
+    MOZ_ASSERT(!source->hasBeenEntered());
     MOZ_ASSERT(source->zone()->compartments().length() == 1);
 
     JSContext* cx = rt->mainContextFromOwnThread();
@@ -8019,35 +8016,35 @@ GCRuntime::mergeCompartments(JSCompartment* source, JSCompartment* target)
     // Cleanup tables and other state in the source realm/zone that will be
     // meaningless after merging into the target realm/zone.
 
-    sourceRealm->clearTables();
+    source->clearTables();
     source->zone()->clearTables();
-    sourceRealm->unsetIsDebuggee();
+    source->unsetIsDebuggee();
 
     // The delazification flag indicates the presence of LazyScripts in a
     // realm for the Debugger API, so if the source realm created LazyScripts,
     // the flag must be propagated to the target realm.
-    if (sourceRealm->needsDelazificationForDebugger())
+    if (source->needsDelazificationForDebugger())
-        targetRealm->scheduleDelazificationForDebugger();
+        target->scheduleDelazificationForDebugger();
 
     // Release any relocated arenas which we may be holding on to as they might
     // be in the source zone
     releaseHeldRelocatedArenas();
 
-    // Fixup compartment pointers in source to refer to target, and make sure
+    // Fixup realm pointers in source to refer to target, and make sure
     // type information generations are in sync.
 
     for (auto script = source->zone()->cellIter<JSScript>(); !script.done(); script.next()) {
-        MOZ_ASSERT(script->compartment() == source);
+        MOZ_ASSERT(script->realm() == source);
-        script->realm_ = JS::GetRealmForCompartment(target);
+        script->realm_ = target;
         script->setTypesGeneration(target->zone()->types.generation);
     }
 
-    GlobalObject* global = targetRealm->maybeGlobal();
+    GlobalObject* global = target->maybeGlobal();
     MOZ_ASSERT(global);
 
     for (auto group = source->zone()->cellIter<ObjectGroup>(); !group.done(); group.next()) {
         // Replace placeholder object prototypes with the correct prototype in
-        // the target compartment.
+        // the target realm.
         TaggedProto proto(group->proto());
         if (proto.isObject()) {
             JSObject* obj = proto.toObject();
@@ -8063,13 +8060,13 @@ GCRuntime::mergeCompartments(JSCompartment* source, JSCompartment* target)
         }
 
         group->setGeneration(target->zone()->types.generation);
-        group->realm_ = JS::GetRealmForCompartment(target);
+        group->realm_ = target;
 
         // Remove any unboxed layouts from the list in the off thread
-        // compartment. These do not need to be reinserted in the target
+        // realm. These do not need to be reinserted in the target
-        // compartment's list, as the list is not required to be complete.
+        // realm's list, as the list is not required to be complete.
         if (UnboxedLayout* layout = group->maybeUnboxedLayoutDontCheckGeneration())
-            layout->detachFromCompartment();
+            layout->detachFromRealm();
     }
 
     // Fixup zone pointers in source's zone to refer to target's zone.
@@ -8092,9 +8089,9 @@ GCRuntime::mergeCompartments(JSCompartment* source, JSCompartment* target)
         }
     }
 
-    // The source should be the only compartment in its zone.
+    // The source should be the only realm in its zone.
-    for (CompartmentsInZoneIter c(source->zone()); !c.done(); c.next())
+    for (RealmsInZoneIter r(source->zone()); !r.done(); r.next())
-        MOZ_ASSERT(c.get() == source);
+        MOZ_ASSERT(r.get() == source);
 
     // Merge the allocator, stats and UIDs in source's zone into target's zone.
     target->zone()->arenas.adoptArenas(rt, &source->zone()->arenas, targetZoneIsCollecting);
@@ -8109,37 +8106,37 @@ GCRuntime::mergeCompartments(JSCompartment* source, JSCompartment* target)
     // Atoms which are marked in source's zone are now marked in target's zone.
     atomMarking.adoptMarkedAtoms(target->zone(), source->zone());
 
-    // Merge script name maps in the target compartment's map.
+    // Merge script name maps in the target realm's map.
-    if (rt->lcovOutput().isEnabled() && sourceRealm->scriptNameMap) {
+    if (rt->lcovOutput().isEnabled() && source->scriptNameMap) {
         AutoEnterOOMUnsafeRegion oomUnsafe;
 
-        if (!targetRealm->scriptNameMap) {
+        if (!target->scriptNameMap) {
-            targetRealm->scriptNameMap = cx->make_unique<ScriptNameMap>();
+            target->scriptNameMap = cx->make_unique<ScriptNameMap>();
 
-            if (!targetRealm->scriptNameMap)
+            if (!target->scriptNameMap)
                 oomUnsafe.crash("Failed to create a script name map.");
 
-            if (!targetRealm->scriptNameMap->init())
+            if (!target->scriptNameMap->init())
                 oomUnsafe.crash("Failed to initialize a script name map.");
         }
 
-        for (ScriptNameMap::Range r = sourceRealm->scriptNameMap->all(); !r.empty(); r.popFront()) {
+        for (ScriptNameMap::Range r = source->scriptNameMap->all(); !r.empty(); r.popFront()) {
             JSScript* key = r.front().key();
             auto value = Move(r.front().value());
-            if (!targetRealm->scriptNameMap->putNew(key, Move(value)))
+            if (!target->scriptNameMap->putNew(key, Move(value)))
                 oomUnsafe.crash("Failed to add an entry in the script name map.");
         }
 
-        sourceRealm->scriptNameMap->clear();
+        source->scriptNameMap->clear();
     }
 
-    // The source compartment is now completely empty, and is the only
+    // The source realm is now completely empty, and is the only realm in its
-    // compartment in its zone, which is the only zone in its group. Delete
+    // compartment, which is the only compartment in its zone. Delete realm,
-    // compartment, zone and group without waiting for this to be cleaned up by
+    // compartment and zone without waiting for this to be cleaned up by a full
-    // a full GC.
+    // GC.
 
     Zone* sourceZone = source->zone();
-    sourceZone->deleteEmptyCompartment(source);
+    sourceZone->deleteEmptyCompartment(source->compartment());
     deleteEmptyZone(sourceZone);
 }
 

js/src/gc/GC.h

@@ -122,9 +122,8 @@ extern void
 IterateScripts(JSContext* cx, JSCompartment* compartment,
                void* data, IterateScriptCallback scriptCallback);
 
-JSCompartment*
+JS::Realm*
-NewCompartment(JSContext* cx, JSPrincipals* principals,
+NewRealm(JSContext* cx, JSPrincipals* principals, const JS::RealmOptions& options);
-               const JS::RealmOptions& options);
 
 namespace gc {
 
@@ -132,10 +131,10 @@ void FinishGC(JSContext* cx);
 
 /*
  * Merge all contents of source into target. This can only be used if source is
- * the only compartment in its zone.
+ * the only realm in its zone.
  */
 void
-MergeCompartments(JSCompartment* source, JSCompartment* target);
+MergeRealms(JS::Realm* source, JS::Realm* target);
 
 enum VerifierType {
     PreBarrierVerifier

js/src/gc/GCRuntime.h

@@ -495,7 +495,7 @@ class GCRuntime
     void joinTask(GCParallelTask& task, gcstats::PhaseKind phase,
                   AutoLockHelperThreadState& locked);
 
-    void mergeCompartments(JSCompartment* source, JSCompartment* target);
+    void mergeRealms(JS::Realm* source, JS::Realm* target);
 
   private:
     enum IncrementalResult

js/src/jit/Ion.cpp

@@ -632,7 +632,7 @@ void
 JitRealm::sweep(JS::Realm* realm)
 {
     // Any outstanding compilations should have been cancelled by the GC.
-    MOZ_ASSERT(!HasOffThreadIonCompile(JS::GetCompartmentForRealm(realm)));
+    MOZ_ASSERT(!HasOffThreadIonCompile(realm));
 
     stubCodes_->sweep();
 
@@ -2843,8 +2843,8 @@ jit::InvalidateAll(FreeOp* fop, Zone* zone)
 {
     // The caller should previously have cancelled off thread compilation.
 #ifdef DEBUG
-    for (CompartmentsInZoneIter comp(zone); !comp.done(); comp.next())
+    for (RealmsInZoneIter realm(zone); !realm.done(); realm.next())
-        MOZ_ASSERT(!HasOffThreadIonCompile(comp));
+        MOZ_ASSERT(!HasOffThreadIonCompile(realm));
 #endif
     if (zone->isAtomsZone())
         return;

js/src/jsapi.cpp

@@ -674,7 +674,7 @@ JS_SetExternalStringSizeofCallback(JSContext* cx, JSExternalStringSizeofCallback
     cx->runtime()->externalStringSizeofCallback = callback;
 }
 
-JS_PUBLIC_API(JSCompartment*)
+JS_PUBLIC_API(Realm*)
 JS::EnterRealm(JSContext* cx, JSObject* target)
 {
     AssertHeapIsIdle();
@@ -682,7 +682,7 @@ JS::EnterRealm(JSContext* cx, JSObject* target)
 
     Realm* oldRealm = cx->realm();
     cx->enterRealmOf(target);
-    return JS::GetCompartmentForRealm(oldRealm);
+    return oldRealm;
 }
 
 JS_PUBLIC_API(void)
@@ -890,7 +890,7 @@ JS_TransplantObject(JSContext* cx, HandleObject origobj, HandleObject target)
         // destination, then we know that we won't find a wrapper in the
         // destination's cross compartment map and that the same
         // object will continue to work.
-        AutoRealmUnchecked ar(cx, origobj->compartment());
+        AutoRealmUnchecked ar(cx, origobj->realm());
         if (!JSObject::swap(cx, origobj, target))
             MOZ_CRASH();
         newIdentity = origobj;
@@ -924,7 +924,7 @@ JS_TransplantObject(JSContext* cx, HandleObject origobj, HandleObject target)
     // Lastly, update the original object to point to the new one.
     if (origobj->compartment() != destination) {
         RootedObject newIdentityWrapper(cx, newIdentity);
-        AutoRealmUnchecked ar(cx, origobj->compartment());
+        AutoRealmUnchecked ar(cx, origobj->realm());
         if (!JS_WrapObject(cx, &newIdentityWrapper))
             MOZ_CRASH();
         MOZ_ASSERT(Wrapper::wrappedObject(newIdentityWrapper) == newIdentity);

js/src/jsapi.h

@@ -1046,7 +1046,7 @@ JS_RefreshCrossCompartmentWrappers(JSContext* cx, JS::Handle<JSObject*> obj);
  *
  *   void foo(JSContext* cx, JSObject* obj) {
  *     // in 'oldRealm'
- *     JSCompartment* oldRealm = JS::EnterRealm(cx, obj);
+ *     JS::Realm* oldRealm = JS::EnterRealm(cx, obj);
  *     // in the realm of 'obj'
  *     JS::LeaveRealm(cx, oldRealm);
  *     // back in 'oldRealm'
@@ -1089,10 +1089,10 @@ namespace JS {
 
 /** NB: This API is infallible; a nullptr return value does not indicate error.
  *
- * Entering a compartment roots the compartment and its global object until the
+ * Entering a realm roots the realm and its global object until the matching
- * matching JS::LeaveRealm() call.
+ * JS::LeaveRealm() call.
  */
-extern JS_PUBLIC_API(JSCompartment*)
+extern JS_PUBLIC_API(JS::Realm*)
 EnterRealm(JSContext* cx, JSObject* target);
 
 extern JS_PUBLIC_API(void)

js/src/proxy/CrossCompartmentWrapper.cpp

@@ -613,6 +613,7 @@ js::RemapWrapper(JSContext* cx, JSObject* wobjArg, JSObject* newTargetArg)
     MOZ_ASSERT(!JS_IsDeadWrapper(origTarget),
                "We don't want a dead proxy in the wrapper map");
     Value origv = ObjectValue(*origTarget);
+    Realm* wrealm = wobj->realm();
     JSCompartment* wcompartment = wobj->compartment();
 
     AutoDisableProxyCheck adpc;
@@ -637,7 +638,7 @@ js::RemapWrapper(JSContext* cx, JSObject* wobjArg, JSObject* newTargetArg)
     // wrapper, |wobj|, since it's been nuked anyway. The wrap() function has
     // the choice to reuse |wobj| or not.
     RootedObject tobj(cx, newTarget);
-    AutoRealmUnchecked ar(cx, wcompartment);
+    AutoRealmUnchecked ar(cx, wrealm);
     if (!wcompartment->rewrap(cx, &tobj, wobj))
         MOZ_CRASH();
 

js/src/vm/Debugger.cpp

@@ -2395,8 +2395,7 @@ class MOZ_RAII ExecutionObservableRealms : public Debugger::ExecutionObservableS
         // AbstractFramePtr can't refer to non-remateralized Ion frames or
         // non-debuggee wasm frames, so if iter refers to one such, we know we
         // don't match.
-        return iter.hasUsableAbstractFramePtr() &&
+        return iter.hasUsableAbstractFramePtr() && realms_.has(iter.realm());
-               realms_.has(JS::GetRealmForCompartment(iter.compartment()));
     }
 
     MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
@@ -3745,7 +3744,7 @@ Debugger::addAllGlobalsAsDebuggees(JSContext* cx, unsigned argc, Value* vp)
         for (RealmsInZoneIter r(zone); !r.done(); r.next()) {
             if (r == dbg->object->realm() || r->creationOptions().invisibleToDebugger())
                 continue;
-            JS::GetCompartmentForRealm(r)->scheduledForDestruction = false;
+            r->compartment()->scheduledForDestruction = false;
             GlobalObject* global = r->maybeGlobal();
             if (global) {
                 Rooted<GlobalObject*> rg(cx, global);
@@ -4962,7 +4961,7 @@ Debugger::findAllGlobals(JSContext* cx, unsigned argc, Value* vp)
             if (r->creationOptions().invisibleToDebugger())
                 continue;
 
-            JS::GetCompartmentForRealm(r)->scheduledForDestruction = false;
+            r->compartment()->scheduledForDestruction = false;
 
             GlobalObject* global = r->maybeGlobal();
 

js/src/vm/GlobalObject.cpp

@@ -506,13 +506,13 @@ GlobalObject::new_(JSContext* cx, const Class* clasp, JSPrincipals* principals,
     MOZ_ASSERT(!cx->isExceptionPending());
     MOZ_ASSERT_IF(cx->realm(), !cx->realm()->isAtomsRealm());
 
-    JSCompartment* compartment = NewCompartment(cx, principals, options);
+    Realm* realm = NewRealm(cx, principals, options);
-    if (!compartment)
+    if (!realm)
         return nullptr;
 
     Rooted<GlobalObject*> global(cx);
     {
-        AutoRealmUnchecked ar(cx, compartment);
+        AutoRealmUnchecked ar(cx, realm);
         global = GlobalObject::createInternal(cx, clasp);
         if (!global)
             return nullptr;

js/src/vm/HelperThreads.cpp

@@ -219,7 +219,7 @@ GetSelectorRuntime(const CompilationSelector& selector)
     struct Matcher
     {
         JSRuntime* match(JSScript* script)    { return script->runtimeFromMainThread(); }
-        JSRuntime* match(JSCompartment* comp) { return comp->runtimeFromMainThread(); }
+        JSRuntime* match(Realm* realm)        { return realm->runtimeFromMainThread(); }
         JSRuntime* match(Zone* zone)          { return zone->runtimeFromMainThread(); }
         JSRuntime* match(ZonesInState zbs)    { return zbs.runtime; }
         JSRuntime* match(JSRuntime* runtime)  { return runtime; }
@@ -236,7 +236,7 @@ JitDataStructuresExist(const CompilationSelector& selector)
     struct Matcher
     {
         bool match(JSScript* script)    { return !!script->realm()->jitRealm(); }
-        bool match(JSCompartment* comp) { return !!JS::GetRealmForCompartment(comp)->jitRealm(); }
+        bool match(Realm* realm)        { return !!realm->jitRealm(); }
         bool match(Zone* zone)          { return !!zone->jitZone(); }
         bool match(ZonesInState zbs)    { return zbs.runtime->hasJitRuntime(); }
         bool match(JSRuntime* runtime)  { return runtime->hasJitRuntime(); }
@@ -255,7 +255,7 @@ IonBuilderMatches(const CompilationSelector& selector, jit::IonBuilder* builder)
         jit::IonBuilder* builder_;
 
         bool match(JSScript* script)    { return script == builder_->script(); }
-        bool match(JSCompartment* comp) { return comp == builder_->script()->compartment(); }
+        bool match(Realm* realm)        { return realm == builder_->script()->realm(); }
         bool match(Zone* zone)          { return zone == builder_->script()->zone(); }
         bool match(JSRuntime* runtime)  { return runtime == builder_->script()->runtimeFromAnyThread(); }
         bool match(AllCompilations all) { return true; }
@@ -343,36 +343,36 @@ js::CancelOffThreadIonCompile(const CompilationSelector& selector, bool discardL
 
 #ifdef DEBUG
 bool
-js::HasOffThreadIonCompile(JSCompartment* comp)
+js::HasOffThreadIonCompile(Realm* realm)
 {
     AutoLockHelperThreadState lock;
 
-    if (!HelperThreadState().threads || JS::GetRealmForCompartment(comp)->isAtomsRealm())
+    if (!HelperThreadState().threads || realm->isAtomsRealm())
         return false;
 
     GlobalHelperThreadState::IonBuilderVector& worklist = HelperThreadState().ionWorklist(lock);
     for (size_t i = 0; i < worklist.length(); i++) {
         jit::IonBuilder* builder = worklist[i];
-        if (builder->script()->compartment() == comp)
+        if (builder->script()->realm() == realm)
             return true;
     }
 
     for (auto& helper : *HelperThreadState().threads) {
-        if (helper.ionBuilder() && helper.ionBuilder()->script()->compartment() == comp)
+        if (helper.ionBuilder() && helper.ionBuilder()->script()->realm() == realm)
             return true;
     }
 
     GlobalHelperThreadState::IonBuilderVector& finished = HelperThreadState().ionFinishedList(lock);
     for (size_t i = 0; i < finished.length(); i++) {
         jit::IonBuilder* builder = finished[i];
-        if (builder->script()->compartment() == comp)
+        if (builder->script()->realm() == realm)
             return true;
     }
 
-    JSRuntime* rt = comp->runtimeFromMainThread();
+    JSRuntime* rt = realm->runtimeFromMainThread();
     jit::IonBuilder* builder = rt->jitRuntime()->ionLazyLinkList(rt).getFirst();
     while (builder) {
-        if (builder->script()->compartment() == comp)
+        if (builder->script()->realm() == realm)
             return true;
         builder = builder->getNext();
     }
@@ -1652,7 +1652,7 @@ bool
 GlobalHelperThreadState::finishParseTask(JSContext* cx, ParseTaskKind kind,
                                          JS::OffThreadToken* token, F&& finishCallback)
 {
-    MOZ_ASSERT(cx->compartment());
+    MOZ_ASSERT(cx->realm());
 
     ScopedJSDeletePtr<ParseTask> parseTask(removeFinishedParseTask(kind, token));
 
@@ -1663,7 +1663,7 @@ GlobalHelperThreadState::finishParseTask(JSContext* cx, ParseTaskKind kind,
         return false;
     }
 
-    mergeParseTaskCompartment(cx, parseTask, cx->compartment());
+    mergeParseTaskRealm(cx, parseTask, cx->realm());
 
     bool ok = finishCallback(parseTask);
 
@@ -1828,18 +1828,17 @@ GlobalHelperThreadState::cancelParseTask(JSRuntime* rt, ParseTaskKind kind,
 }
 
 void
-GlobalHelperThreadState::mergeParseTaskCompartment(JSContext* cx, ParseTask* parseTask,
+GlobalHelperThreadState::mergeParseTaskRealm(JSContext* cx, ParseTask* parseTask, Realm* dest)
-                                                   JSCompartment* dest)
 {
     // After we call LeaveParseTaskZone() it's not safe to GC until we have
-    // finished merging the contents of the parse task's compartment into the
+    // finished merging the contents of the parse task's realm into the
-    // destination compartment.
+    // destination realm.
     JS::AutoAssertNoGC nogc(cx);
 
     LeaveParseTaskZone(cx->runtime(), parseTask);
 
-    // Move the parsed script and all its contents into the desired compartment.
+    // Move the parsed script and all its contents into the desired realm.
-    gc::MergeCompartments(parseTask->parseGlobal->compartment(), dest);
+    gc::MergeRealms(parseTask->parseGlobal->realm(), dest);
 }
 
 void

js/src/vm/HelperThreads.h

@@ -305,7 +305,7 @@ class GlobalHelperThreadState
 
     void cancelParseTask(JSRuntime* rt, ParseTaskKind kind, JS::OffThreadToken* token);
 
-    void mergeParseTaskCompartment(JSContext* cx, ParseTask* parseTask, JSCompartment* dest);
+    void mergeParseTaskRealm(JSContext* cx, ParseTask* parseTask, JS::Realm* dest);
 
     void trace(JSTracer* trc, js::gc::AutoTraceSession& session);
 
@@ -529,7 +529,7 @@ struct ZonesInState { JSRuntime* runtime; JS::Zone::GCState state; };
 struct CompilationsUsingNursery { JSRuntime* runtime; };
 
 using CompilationSelector = mozilla::Variant<JSScript*,
-                                             JSCompartment*,
+                                             JS::Realm*,
                                              Zone*,
                                              ZonesInState,
                                              JSRuntime*,
@@ -549,9 +549,9 @@ CancelOffThreadIonCompile(JSScript* script)
 }
 
 inline void
-CancelOffThreadIonCompile(JSCompartment* comp)
+CancelOffThreadIonCompile(JS::Realm* realm)
 {
-    CancelOffThreadIonCompile(CompilationSelector(comp), true);
+    CancelOffThreadIonCompile(CompilationSelector(realm), true);
 }
 
 inline void
@@ -580,7 +580,7 @@ CancelOffThreadIonCompilesUsingNurseryPointers(JSRuntime* runtime)
 
 #ifdef DEBUG
 bool
-HasOffThreadIonCompile(JSCompartment* comp);
+HasOffThreadIonCompile(JS::Realm* realm);
 #endif
 
 /* Cancel all scheduled, in progress or finished parses for runtime. */

js/src/vm/JSCompartment-inl.h

@@ -91,8 +91,8 @@ js::AutoAtomsRealm::AutoAtomsRealm(JSContext* cx,
   : AutoRealm(cx, cx->atomsRealm(lock), lock)
 {}
 
-js::AutoRealmUnchecked::AutoRealmUnchecked(JSContext* cx, JSCompartment* target)
+js::AutoRealmUnchecked::AutoRealmUnchecked(JSContext* cx, JS::Realm* target)
-  : AutoRealm(cx, JS::GetRealmForCompartment(target))
+  : AutoRealm(cx, target)
 {}
 
 inline bool

js/src/vm/JSCompartment.h

@@ -904,6 +904,10 @@ class JS::Realm : private JSCompartment
                                 size_t* privateData,
                                 size_t* scriptCountsMapArg);
 
+    JSCompartment* compartment() {
+        return this;
+    }
+
     JS::Zone* zone() {
         return zone_;
     }
@@ -1384,7 +1388,7 @@ class AutoAtomsRealm : protected AutoRealm
 class AutoRealmUnchecked : protected AutoRealm
 {
   public:
-    inline AutoRealmUnchecked(JSContext* cx, JSCompartment* target);
+    inline AutoRealmUnchecked(JSContext* cx, JS::Realm* target);
 };
 
 /*

js/src/vm/ObjectGroup.h

@@ -32,7 +32,7 @@ class CompilerConstraintList;
 class ObjectGroupRealm;
 
 namespace gc {
-void MergeCompartments(JSCompartment* source, JSCompartment* target);
+void MergeRealms(JS::Realm* source, JS::Realm* target);
 } // namespace gc
 
 /*

js/src/vm/Runtime.cpp

@@ -225,7 +225,7 @@ JSRuntime::init(JSContext* cx, uint32_t maxbytes, uint32_t maxNurseryBytes)
         return false;
 
     gc.atomsZone = atomsZone.get();
-    if (!atomsZone->compartments().append(JS::GetCompartmentForRealm(atomsRealm.get())))
+    if (!atomsZone->compartments().append(atomsRealm->compartment()))
         return false;
 
     atomsRealm->setIsSystem(true);

js/src/vm/SavedStacks.cpp

@@ -1474,7 +1474,7 @@ SavedStacks::insertFrames(JSContext* cx, MutableHandleSavedFrame frame,
         // needed to construct the SavedFrame::Lookup.
         Rooted<LocationValue> location(cx);
         {
-            AutoRealmUnchecked ar(cx, iter.compartment());
+            AutoRealmUnchecked ar(cx, iter.realm());
             if (!cx->realm()->savedStacks().getLocation(cx, iter, &location))
                 return false;
         }

js/src/vm/SelfHosting.cpp

@@ -2791,12 +2791,10 @@ JSRuntime::createSelfHostingGlobal(JSContext* cx)
     options.creationOptions().setNewZone();
     options.behaviors().setDiscardSource(true);
 
-    JSCompartment* compartment = NewCompartment(cx, nullptr, options);
+    Realm* realm = NewRealm(cx, nullptr, options);
-    if (!compartment)
+    if (!realm)
         return nullptr;
 
-    JS::Realm* realm = JS::GetRealmForCompartment(compartment);
-
     static const ClassOps shgClassOps = {
         nullptr, nullptr, nullptr, nullptr,
         nullptr, nullptr, nullptr, nullptr,
@@ -2809,7 +2807,7 @@ JSRuntime::createSelfHostingGlobal(JSContext* cx)
         &shgClassOps
     };
 
-    AutoRealmUnchecked ar(cx, compartment);
+    AutoRealmUnchecked ar(cx, realm);
     Rooted<GlobalObject*> shg(cx, GlobalObject::createInternal(cx, &shgClass));
     if (!shg)
         return nullptr;

js/src/vm/Shape.h

@@ -451,7 +451,6 @@ class BaseShape : public gc::TenuredCell
     friend class Shape;
     friend struct StackBaseShape;
     friend struct StackShape;
-    friend void gc::MergeCompartments(JSCompartment* source, JSCompartment* target);
 
     enum Flag {
         /* Owned by the referring shape. */

js/src/vm/Stack.cpp

@@ -901,6 +901,17 @@ FrameIter::compartment() const
     MOZ_CRASH("Unexpected state");
 }
 
+Realm*
+FrameIter::realm() const
+{
+    MOZ_ASSERT(!done());
+
+    if (hasScript())
+        return script()->realm();
+
+    return wasmInstance()->realm();
+}
+
 bool
 FrameIter::isEvalFrame() const
 {
@@ -1622,9 +1633,9 @@ jit::JitActivation::getRematerializedFrame(JSContext* cx, const JSJitFrameIter&
         MaybeReadFallback recover(cx, this, &iter);
 
         // Frames are often rematerialized with the cx inside a Debugger's
-        // compartment. To recover slots and to create CallObjects, we need to
+        // realm. To recover slots and to create CallObjects, we need to
-        // be in the activation's compartment.
+        // be in the script's realm.
-        AutoRealmUnchecked ar(cx, compartment_);
+        AutoRealmUnchecked ar(cx, iter.script()->realm());
 
         if (!RematerializedFrame::RematerializeInlineFrames(cx, top, inlineIter, recover, frames))
             return nullptr;

js/src/vm/Stack.h

@@ -2045,6 +2045,7 @@ class FrameIter
 
     FrameIter& operator++();
 
+    JS::Realm* realm() const;
     JSCompartment* compartment() const;
     Activation* activation() const { return data_.activations_.activation(); }
 

js/src/vm/TypeInference.cpp

@@ -4417,10 +4417,10 @@ ObjectGroup::sweep(const AutoSweepObjectGroup& sweep, AutoClearTypeInferenceStat
 
     if (auto* layout = maybeUnboxedLayout(sweep)) {
         // Remove unboxed layouts that are about to be finalized from the
-        // compartment wide list while we are still on the main thread.
+        // realm wide list while we are still on the main thread.
         ObjectGroup* group = this;
         if (IsAboutToBeFinalizedUnbarriered(&group))
-            layout->detachFromCompartment();
+            layout->detachFromRealm();
 
         if (layout->newScript())
             layout->newScript()->sweep();

js/src/vm/UnboxedObject.cpp

@@ -305,7 +305,7 @@ UnboxedLayout::makeConstructorCode(JSContext* cx, HandleObjectGroup group)
 }
 
 void
-UnboxedLayout::detachFromCompartment()
+UnboxedLayout::detachFromRealm()
 {
     if (isInList())
         remove();

js/src/vm/UnboxedObject.h

@@ -124,7 +124,7 @@ class UnboxedLayout : public mozilla::LinkedListElement<UnboxedLayout>
         constructorCode_.init(nullptr);
     }
 
-    void detachFromCompartment();
+    void detachFromRealm();
 
     const PropertyVector& properties() const {
         return properties_;

js/src/wasm/WasmSignalHandlers.cpp

@@ -954,7 +954,7 @@ HandleFault(PEXCEPTION_POINTERS exception)
     if (!IsHeapAccessAddress(*instance, faultingAddress))
         return false;
 
-    MOZ_ASSERT(activation->compartment() == JS::GetCompartmentForRealm(instance->realm()));
+    MOZ_ASSERT(activation->compartment() == instance->realm()->compartment());
 
     return HandleOutOfBounds(context, pc, faultingAddress, moduleSegment, *instance, activation, ppc);
 }
@@ -1061,7 +1061,7 @@ HandleMachException(JSContext* cx, const ExceptionRequest& request)
         return false;
 
     JitActivation* activation = cx->activation()->asJit();
-    MOZ_ASSERT(activation->compartment() == JS::GetCompartmentForRealm(instance->realm()));
+    MOZ_ASSERT(activation->compartment() == instance->realm()->compartment());
 
     if (request.body.exception == EXC_BAD_INSTRUCTION) {
         Trap trap;
@@ -1283,7 +1283,7 @@ HandleFault(int signum, siginfo_t* info, void* ctx)
         return false;
 
     JitActivation* activation = TlsContext.get()->activation()->asJit();
-    MOZ_ASSERT(activation->compartment() == JS::GetCompartmentForRealm(instance->realm()));
+    MOZ_ASSERT(activation->compartment() == instance->realm()->compartment());
 
     if (signum == kWasmTrapSignal) {
         // Wasm traps for MIPS raise only integer overflow fp exception.

xpcom/tests/gtest/TestGCPostBarriers.cpp

@@ -100,7 +100,7 @@ CreateGlobalAndRunTest(JSContext* cx)
   global = JS_NewGlobalObject(cx, &GlobalClass, nullptr, JS::FireOnNewGlobalHook, options);
   ASSERT_TRUE(global != nullptr);
 
-  JS::Realm* oldRealm = JS::GetRealmForCompartment(JS::EnterRealm(cx, global));
+  JS::Realm* oldRealm = JS::EnterRealm(cx, global);
 
   typedef Heap<JSObject*> ElementT;