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Diffstat (limited to 'js/src/gc/Zone.h')
| -rw-r--r-- | js/src/gc/Zone.h | 711 |
1 files changed, 711 insertions, 0 deletions
diff --git a/js/src/gc/Zone.h b/js/src/gc/Zone.h new file mode 100644 index 0000000000..5c93270a14 --- /dev/null +++ b/js/src/gc/Zone.h @@ -0,0 +1,711 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef gc_Zone_h +#define gc_Zone_h + +#include "mozilla/Atomics.h" +#include "mozilla/HashFunctions.h" +#include "mozilla/SegmentedVector.h" + +#include "ds/Bitmap.h" +#include "gc/ArenaList.h" +#include "gc/Barrier.h" +#include "gc/FindSCCs.h" +#include "gc/GCMarker.h" +#include "gc/NurseryAwareHashMap.h" +#include "gc/Statistics.h" +#include "gc/ZoneAllocator.h" +#include "js/GCHashTable.h" +#include "vm/AtomsTable.h" +#include "vm/JSFunction.h" + +namespace js { + +class RegExpZone; +class WeakRefObject; + +namespace jit { +class JitZone; +} // namespace jit + +namespace gc { + +class ZoneList; + +using ZoneComponentFinder = ComponentFinder<JS::Zone>; + +struct UniqueIdGCPolicy { + static bool needsSweep(Cell** cell, uint64_t* value); +}; + +// Maps a Cell* to a unique, 64bit id. +using UniqueIdMap = GCHashMap<Cell*, uint64_t, PointerHasher<Cell*>, + SystemAllocPolicy, UniqueIdGCPolicy>; + +extern uint64_t NextCellUniqueId(JSRuntime* rt); + +template <typename T> +class ZoneAllCellIter; + +template <typename T> +class ZoneCellIter; + +// A vector of FinalizationRecord objects, or CCWs to them. +using FinalizationRecordVector = GCVector<HeapPtrObject, 1, ZoneAllocPolicy>; + +} // namespace gc + +// If two different nursery strings are wrapped into the same zone, and have +// the same contents, then deduplication may make them duplicates. +// `DuplicatesPossible` will allow this and map both wrappers to the same (now +// tenured) source string. +using StringWrapperMap = + NurseryAwareHashMap<JSString*, JSString*, DefaultHasher<JSString*>, + ZoneAllocPolicy, DuplicatesPossible>; + +class MOZ_NON_TEMPORARY_CLASS ExternalStringCache { + static const size_t NumEntries = 4; + mozilla::Array<JSString*, NumEntries> entries_; + + ExternalStringCache(const ExternalStringCache&) = delete; + void operator=(const ExternalStringCache&) = delete; + + public: + ExternalStringCache() { purge(); } + void purge() { mozilla::PodArrayZero(entries_); } + + MOZ_ALWAYS_INLINE JSString* lookup(const char16_t* chars, size_t len) const; + MOZ_ALWAYS_INLINE void put(JSString* s); +}; + +class MOZ_NON_TEMPORARY_CLASS FunctionToStringCache { + struct Entry { + BaseScript* script; + JSString* string; + + void set(BaseScript* scriptArg, JSString* stringArg) { + script = scriptArg; + string = stringArg; + } + }; + static const size_t NumEntries = 2; + mozilla::Array<Entry, NumEntries> entries_; + + FunctionToStringCache(const FunctionToStringCache&) = delete; + void operator=(const FunctionToStringCache&) = delete; + + public: + FunctionToStringCache() { purge(); } + void purge() { mozilla::PodArrayZero(entries_); } + + MOZ_ALWAYS_INLINE JSString* lookup(BaseScript* script) const; + MOZ_ALWAYS_INLINE void put(BaseScript* script, JSString* string); +}; + +// WeakRefHeapPtrVector is a GCVector of WeakRefObjects. +class WeakRefHeapPtrVector + : public GCVector<js::HeapPtrObject, 1, js::ZoneAllocPolicy> { + public: + using GCVector::GCVector; + + // call in compacting, to update the target in each WeakRefObject. + void sweep(js::HeapPtrObject& target); +}; + +// WeakRefMap is a per-zone GCHashMap, which maps from the target of the JS +// WeakRef to the list of JS WeakRefs. +class WeakRefMap + : public GCHashMap<HeapPtrObject, WeakRefHeapPtrVector, + MovableCellHasher<HeapPtrObject>, ZoneAllocPolicy> { + public: + using GCHashMap::GCHashMap; + using Base = GCHashMap<HeapPtrObject, WeakRefHeapPtrVector, + MovableCellHasher<HeapPtrObject>, ZoneAllocPolicy>; + void sweep(gc::StoreBuffer* sbToLock); +}; + +} // namespace js + +namespace JS { + +// [SMDOC] GC Zones +// +// A zone is a collection of compartments. Every compartment belongs to exactly +// one zone. In Firefox, there is roughly one zone per tab along with a system +// zone for everything else. Zones mainly serve as boundaries for garbage +// collection. Unlike compartments, they have no special security properties. +// +// Every GC thing belongs to exactly one zone. GC things from the same zone but +// different compartments can share an arena (4k page). GC things from different +// zones cannot be stored in the same arena. The garbage collector is capable of +// collecting one zone at a time; it cannot collect at the granularity of +// compartments. +// +// GC things are tied to zones and compartments as follows: +// +// - JSObjects belong to a compartment and cannot be shared between +// compartments. If an object needs to point to a JSObject in a different +// compartment, regardless of zone, it must go through a cross-compartment +// wrapper. Each compartment keeps track of its outgoing wrappers in a table. +// JSObjects find their compartment via their ObjectGroup. +// +// - JSStrings do not belong to any particular compartment, but they do belong +// to a zone. Thus, two different compartments in the same zone can point to a +// JSString. When a string needs to be wrapped, we copy it if it's in a +// different zone and do nothing if it's in the same zone. Thus, transferring +// strings within a zone is very efficient. +// +// - Shapes and base shapes belong to a zone and are shared between compartments +// in that zone where possible. Accessor shapes store getter and setter +// JSObjects which belong to a single compartment, so these shapes and all +// their descendants can't be shared with other compartments. +// +// - Scripts are also compartment-local and cannot be shared. A script points to +// its compartment. +// +// - ObjectGroup and JitCode objects belong to a compartment and cannot be +// shared. There is no mechanism to obtain the compartment from a JitCode +// object. +// +// A zone remains alive as long as any GC things in the zone are alive. A +// compartment remains alive as long as any JSObjects, scripts, shapes, or base +// shapes within it are alive. +// +// We always guarantee that a zone has at least one live compartment by refusing +// to delete the last compartment in a live zone. +class Zone : public js::ZoneAllocator, public js::gc::GraphNodeBase<JS::Zone> { + private: + enum class HelperThreadUse : uint32_t { None, Pending, Active }; + mozilla::Atomic<HelperThreadUse, mozilla::SequentiallyConsistent> + helperThreadUse_; + + // The helper thread context with exclusive access to this zone, if + // usedByHelperThread(), or nullptr when on the main thread. + js::UnprotectedData<JSContext*> helperThreadOwnerContext_; + + public: + js::gc::ArenaLists arenas; + + // Per-zone data for use by an embedder. + js::ZoneData<void*> data; + + js::ZoneData<uint32_t> tenuredBigInts; + + js::ZoneOrIonCompileData<uint64_t> nurseryAllocatedStrings; + + // Number of marked/finalzied JSString/JSFatInlineString during major GC. + js::ZoneOrGCTaskData<size_t> markedStrings; + js::ZoneOrGCTaskData<size_t> finalizedStrings; + + js::ZoneData<bool> allocNurseryStrings; + js::ZoneData<bool> allocNurseryBigInts; + + // When true, skip calling the metadata callback. We use this: + // - to avoid invoking the callback recursively; + // - to avoid observing lazy prototype setup (which confuses callbacks that + // want to use the types being set up!); + // - to avoid attaching allocation stacks to allocation stack nodes, which + // is silly + // And so on. + js::ZoneData<bool> suppressAllocationMetadataBuilder; + + // Script side-tables. These used to be held by Realm, but are now placed + // here in order to allow JSScript to access them during finalize (see bug + // 1568245; this change in 1575350). The tables are initialized lazily by + // JSScript. + js::UniquePtr<js::ScriptCountsMap> scriptCountsMap; + js::UniquePtr<js::ScriptLCovMap> scriptLCovMap; + js::UniquePtr<js::DebugScriptMap> debugScriptMap; +#ifdef MOZ_VTUNE + js::UniquePtr<js::ScriptVTuneIdMap> scriptVTuneIdMap; +#endif +#ifdef JS_CACHEIR_SPEW + js::UniquePtr<js::ScriptFinalWarmUpCountMap> scriptFinalWarmUpCountMap; +#endif + + js::ZoneData<js::StringStats> previousGCStringStats; + js::ZoneData<js::StringStats> stringStats; + +#ifdef DEBUG + js::MainThreadData<unsigned> gcSweepGroupIndex; +#endif + + private: + // Side map for storing unique ids for cells, independent of address. + js::ZoneOrGCTaskData<js::gc::UniqueIdMap> uniqueIds_; + + // Number of allocations since the most recent minor GC for this thread. + mozilla::Atomic<uint32_t, mozilla::Relaxed> tenuredAllocsSinceMinorGC_; + + // Live weakmaps in this zone. + js::ZoneOrGCTaskData<mozilla::LinkedList<js::WeakMapBase>> gcWeakMapList_; + + // The set of compartments in this zone. + using CompartmentVector = + js::Vector<JS::Compartment*, 1, js::SystemAllocPolicy>; + js::MainThreadOrGCTaskData<CompartmentVector> compartments_; + + // All cross-zone string wrappers in the zone. + js::MainThreadOrGCTaskData<js::StringWrapperMap> crossZoneStringWrappers_; + + // This zone's gray roots. + using GrayRootVector = + mozilla::SegmentedVector<js::gc::Cell*, 1024 * sizeof(js::gc::Cell*), + js::SystemAllocPolicy>; + js::ZoneOrGCTaskData<GrayRootVector> gcGrayRoots_; + + // List of non-ephemeron weak containers to sweep during + // beginSweepingSweepGroup. + js::ZoneOrGCTaskData<mozilla::LinkedList<detail::WeakCacheBase>> weakCaches_; + + // Mapping from not yet marked keys to a vector of all values that the key + // maps to in any live weak map. Separate tables for nursery and tenured + // keys. + js::ZoneOrGCTaskData<js::gc::WeakKeyTable> gcWeakKeys_; + js::ZoneOrGCTaskData<js::gc::WeakKeyTable> gcNurseryWeakKeys_; + + // Keep track of all TypeDescr and related objects in this compartment. + // This is used by the GC to trace them all first when compacting, since the + // TypedObject trace hook may access these objects. + // + // There are no barriers here - the set contains only tenured objects so no + // post-barrier is required, and these are weak references so no pre-barrier + // is required. + using TypeDescrObjectSet = + js::GCHashSet<JSObject*, js::MovableCellHasher<JSObject*>, + js::SystemAllocPolicy>; + + js::ZoneData<JS::WeakCache<TypeDescrObjectSet>> typeDescrObjects_; + + js::MainThreadData<js::UniquePtr<js::RegExpZone>> regExps_; + + // Bitmap of atoms marked by this zone. + js::ZoneOrGCTaskData<js::SparseBitmap> markedAtoms_; + + // Set of atoms recently used by this Zone. Purged on GC. + js::ZoneOrGCTaskData<js::AtomSet> atomCache_; + + // Cache storing allocated external strings. Purged on GC. + js::ZoneOrGCTaskData<js::ExternalStringCache> externalStringCache_; + + // Cache for Function.prototype.toString. Purged on GC. + js::ZoneOrGCTaskData<js::FunctionToStringCache> functionToStringCache_; + + // Shared Shape property tree. + js::ZoneData<js::PropertyTree> propertyTree_; + + // Set of all unowned base shapes in the Zone. + js::ZoneData<js::BaseShapeSet> baseShapes_; + + // Set of initial shapes in the Zone. For certain prototypes -- namely, + // those of various builtin classes -- there are two entries: one for a + // lookup via TaggedProto, and one for a lookup via JSProtoKey. See + // InitialShapeProto. + js::ZoneData<js::InitialShapeSet> initialShapes_; + + // List of shapes that may contain nursery pointers. + using NurseryShapeVector = + js::Vector<js::AccessorShape*, 0, js::SystemAllocPolicy>; + js::ZoneData<NurseryShapeVector> nurseryShapes_; + + // The set of all finalization registries in this zone. + using FinalizationRegistrySet = + GCHashSet<js::HeapPtrObject, js::MovableCellHasher<js::HeapPtrObject>, + js::ZoneAllocPolicy>; + js::ZoneOrGCTaskData<FinalizationRegistrySet> finalizationRegistries_; + + // A map from finalization registry targets to a list of finalization records + // representing registries that the target is registered with and their + // associated held values. + using FinalizationRecordMap = + GCHashMap<js::HeapPtrObject, js::gc::FinalizationRecordVector, + js::MovableCellHasher<js::HeapPtrObject>, js::ZoneAllocPolicy>; + js::ZoneOrGCTaskData<FinalizationRecordMap> finalizationRecordMap_; + + js::ZoneOrGCTaskData<js::jit::JitZone*> jitZone_; + + js::MainThreadData<bool> gcScheduled_; + js::MainThreadData<bool> gcScheduledSaved_; + js::MainThreadData<bool> gcPreserveCode_; + js::ZoneData<bool> keepShapeCaches_; + js::MainThreadData<bool> wasCollected_; + + // Allow zones to be linked into a list + js::MainThreadOrGCTaskData<Zone*> listNext_; + static Zone* const NotOnList; + friend class js::gc::ZoneList; + + js::ZoneOrGCTaskData<js::WeakRefMap> weakRefMap_; + + using KeptAliveSet = + JS::GCHashSet<js::HeapPtrObject, js::MovableCellHasher<js::HeapPtrObject>, + js::ZoneAllocPolicy>; + friend class js::WeakRefObject; + js::ZoneOrGCTaskData<KeptAliveSet> keptObjects; + + public: + static JS::Zone* from(ZoneAllocator* zoneAlloc) { + return static_cast<Zone*>(zoneAlloc); + } + + explicit Zone(JSRuntime* rt, Kind kind = NormalZone); + ~Zone(); + + MOZ_MUST_USE bool init(); + + void destroy(JSFreeOp* fop); + + bool ownedByCurrentHelperThread(); + void setHelperThreadOwnerContext(JSContext* cx); + + // Whether this zone was created for use by a helper thread. + bool createdForHelperThread() const { + return helperThreadUse_ != HelperThreadUse::None; + } + // Whether this zone is currently in use by a helper thread. + bool usedByHelperThread() { + MOZ_ASSERT_IF(isAtomsZone(), helperThreadUse_ == HelperThreadUse::None); + return helperThreadUse_ == HelperThreadUse::Active; + } + void setCreatedForHelperThread() { + MOZ_ASSERT(helperThreadUse_ == HelperThreadUse::None); + helperThreadUse_ = HelperThreadUse::Pending; + } + void setUsedByHelperThread() { + MOZ_ASSERT(helperThreadUse_ == HelperThreadUse::Pending); + helperThreadUse_ = HelperThreadUse::Active; + } + void clearUsedByHelperThread() { + MOZ_ASSERT(helperThreadUse_ != HelperThreadUse::None); + helperThreadUse_ = HelperThreadUse::None; + } + + MOZ_MUST_USE bool findSweepGroupEdges(Zone* atomsZone); + + enum ShouldDiscardBaselineCode : bool { + KeepBaselineCode = false, + DiscardBaselineCode + }; + + enum ShouldDiscardJitScripts : bool { + KeepJitScripts = false, + DiscardJitScripts + }; + + void discardJitCode( + JSFreeOp* fop, + ShouldDiscardBaselineCode discardBaselineCode = DiscardBaselineCode, + ShouldDiscardJitScripts discardJitScripts = KeepJitScripts); + + void addSizeOfIncludingThis( + mozilla::MallocSizeOf mallocSizeOf, JS::CodeSizes* code, + size_t* regexpZone, size_t* jitZone, size_t* baselineStubsOptimized, + size_t* uniqueIdMap, size_t* shapeCaches, size_t* atomsMarkBitmaps, + size_t* compartmentObjects, size_t* crossCompartmentWrappersTables, + size_t* compartmentsPrivateData, size_t* scriptCountsMapArg); + + // Iterate over all cells in the zone. See the definition of ZoneCellIter + // in gc/GC-inl.h for the possible arguments and documentation. + template <typename T, typename... Args> + js::gc::ZoneCellIter<T> cellIter(Args&&... args) { + return js::gc::ZoneCellIter<T>(const_cast<Zone*>(this), + std::forward<Args>(args)...); + } + + // As above, but can return about-to-be-finalised things. + template <typename T, typename... Args> + js::gc::ZoneAllCellIter<T> cellIterUnsafe(Args&&... args) { + return js::gc::ZoneAllCellIter<T>(const_cast<Zone*>(this), + std::forward<Args>(args)...); + } + + bool hasMarkedRealms(); + + void scheduleGC() { + MOZ_ASSERT(!RuntimeHeapIsBusy()); + gcScheduled_ = true; + } + void unscheduleGC() { gcScheduled_ = false; } + bool isGCScheduled() { return gcScheduled_; } + + void setPreservingCode(bool preserving) { gcPreserveCode_ = preserving; } + bool isPreservingCode() const { return gcPreserveCode_; } + + // Whether this zone can currently be collected. + bool canCollect(); + + void changeGCState(GCState prev, GCState next); + + bool isCollecting() const { + MOZ_ASSERT(js::CurrentThreadCanAccessRuntime(runtimeFromMainThread())); + return isCollectingFromAnyThread(); + } + + bool isCollectingFromAnyThread() const { + if (RuntimeHeapIsCollecting()) { + return gcState_ != NoGC; + } else { + return needsIncrementalBarrier(); + } + } + + bool shouldMarkInZone() const { + // We only need to check needsIncrementalBarrier() for the pre-barrier + // verifier. During marking isGCMarking() will always be true. + return needsIncrementalBarrier() || isGCMarking(); + } + + // Was this zone collected in the last GC. + bool wasCollected() const { return wasCollected_; } + void setWasCollected(bool v) { wasCollected_ = v; } + + // Get a number that is incremented whenever this zone is collected, and + // possibly at other times too. + uint64_t gcNumber(); + + void setNeedsIncrementalBarrier(bool needs); + const uint32_t* addressOfNeedsIncrementalBarrier() const { + return &needsIncrementalBarrier_; + } + + static constexpr size_t offsetOfNeedsIncrementalBarrier() { + return offsetof(Zone, needsIncrementalBarrier_); + } + + js::jit::JitZone* getJitZone(JSContext* cx) { + return jitZone_ ? jitZone_ : createJitZone(cx); + } + js::jit::JitZone* jitZone() { return jitZone_; } + + void prepareForCompacting(); + + void sweepAfterMinorGC(JSTracer* trc); + void sweepUniqueIds(); + void sweepWeakMaps(); + void sweepCompartments(JSFreeOp* fop, bool keepAtleastOne, bool lastGC); + + js::gc::UniqueIdMap& uniqueIds() { return uniqueIds_.ref(); } + + void notifyObservingDebuggers(); + + void clearTables(); + + void addTenuredAllocsSinceMinorGC(uint32_t allocs) { + tenuredAllocsSinceMinorGC_ += allocs; + } + + uint32_t getAndResetTenuredAllocsSinceMinorGC() { + return tenuredAllocsSinceMinorGC_.exchange(0); + } + + mozilla::LinkedList<js::WeakMapBase>& gcWeakMapList() { + return gcWeakMapList_.ref(); + } + + CompartmentVector& compartments() { return compartments_.ref(); } + + js::StringWrapperMap& crossZoneStringWrappers() { + return crossZoneStringWrappers_.ref(); + } + const js::StringWrapperMap& crossZoneStringWrappers() const { + return crossZoneStringWrappers_.ref(); + } + + void dropStringWrappersOnGC(); + + void sweepAllCrossCompartmentWrappers(); + static void fixupAllCrossCompartmentWrappersAfterMovingGC(JSTracer* trc); + + GrayRootVector& gcGrayRoots() { return gcGrayRoots_.ref(); } + + mozilla::LinkedList<detail::WeakCacheBase>& weakCaches() { + return weakCaches_.ref(); + } + void registerWeakCache(detail::WeakCacheBase* cachep) { + weakCaches().insertBack(cachep); + } + + void beforeClearDelegate(JSObject* wrapper, JSObject* delegate) { + if (needsIncrementalBarrier()) { + beforeClearDelegateInternal(wrapper, delegate); + } + } + + void afterAddDelegate(JSObject* wrapper) { + if (needsIncrementalBarrier()) { + afterAddDelegateInternal(wrapper); + } + } + + void beforeClearDelegateInternal(JSObject* wrapper, JSObject* delegate); + void afterAddDelegateInternal(JSObject* wrapper); + js::gc::WeakKeyTable& gcWeakKeys() { return gcWeakKeys_.ref(); } + js::gc::WeakKeyTable& gcNurseryWeakKeys() { return gcNurseryWeakKeys_.ref(); } + + js::gc::WeakKeyTable& gcWeakKeys(const js::gc::Cell* cell) { + return cell->isTenured() ? gcWeakKeys() : gcNurseryWeakKeys(); + } + + // Perform all pending weakmap entry marking for this zone after + // transitioning to weak marking mode. + js::gc::IncrementalProgress enterWeakMarkingMode(js::GCMarker* marker, + js::SliceBudget& budget); + void checkWeakMarkingMode(); + + // A set of edges from this zone to other zones used during GC to calculate + // sweep groups. + NodeSet& gcSweepGroupEdges() { + return gcGraphEdges; // Defined in GraphNodeBase base class. + } + bool hasSweepGroupEdgeTo(Zone* otherZone) const { + return gcGraphEdges.has(otherZone); + } + MOZ_MUST_USE bool addSweepGroupEdgeTo(Zone* otherZone) { + MOZ_ASSERT(otherZone->isGCMarking()); + return gcSweepGroupEdges().put(otherZone); + } + void clearSweepGroupEdges() { gcSweepGroupEdges().clear(); } + + js::RegExpZone& regExps() { return *regExps_.ref(); } + + JS::WeakCache<TypeDescrObjectSet>& typeDescrObjects() { + return typeDescrObjects_.ref(); + } + + bool addTypeDescrObject(JSContext* cx, HandleObject obj); + + js::SparseBitmap& markedAtoms() { return markedAtoms_.ref(); } + + js::AtomSet& atomCache() { return atomCache_.ref(); } + + void purgeAtomCache(); + + js::ExternalStringCache& externalStringCache() { + return externalStringCache_.ref(); + }; + + js::FunctionToStringCache& functionToStringCache() { + return functionToStringCache_.ref(); + } + + js::PropertyTree& propertyTree() { return propertyTree_.ref(); } + + js::BaseShapeSet& baseShapes() { return baseShapes_.ref(); } + + js::InitialShapeSet& initialShapes() { return initialShapes_.ref(); } + + NurseryShapeVector& nurseryShapes() { return nurseryShapes_.ref(); } + + void fixupInitialShapeTable(); + void fixupAfterMovingGC(); + void fixupScriptMapsAfterMovingGC(JSTracer* trc); + + static js::HashNumber UniqueIdToHash(uint64_t uid); + + // Creates a HashNumber based on getUniqueId. Returns false on OOM. + MOZ_MUST_USE bool getHashCode(js::gc::Cell* cell, js::HashNumber* hashp); + + // Gets an existing UID in |uidp| if one exists. + MOZ_MUST_USE bool maybeGetUniqueId(js::gc::Cell* cell, uint64_t* uidp); + + // Puts an existing UID in |uidp|, or creates a new UID for this Cell and + // puts that into |uidp|. Returns false on OOM. + MOZ_MUST_USE bool getOrCreateUniqueId(js::gc::Cell* cell, uint64_t* uidp); + + js::HashNumber getHashCodeInfallible(js::gc::Cell* cell); + uint64_t getUniqueIdInfallible(js::gc::Cell* cell); + + // Return true if this cell has a UID associated with it. + MOZ_MUST_USE bool hasUniqueId(js::gc::Cell* cell); + + // Transfer an id from another cell. This must only be called on behalf of a + // moving GC. This method is infallible. + void transferUniqueId(js::gc::Cell* tgt, js::gc::Cell* src); + + // Remove any unique id associated with this Cell. + void removeUniqueId(js::gc::Cell* cell); + + // When finished parsing off-thread, transfer any UIDs we created in the + // off-thread zone into the target zone. + void adoptUniqueIds(JS::Zone* source); + + bool keepShapeCaches() const { return keepShapeCaches_; } + void setKeepShapeCaches(bool b) { keepShapeCaches_ = b; } + + // Delete an empty compartment after its contents have been merged. + void deleteEmptyCompartment(JS::Compartment* comp); + + void clearRootsForShutdownGC(); + void finishRoots(); + + void traceScriptTableRoots(JSTracer* trc); + + void clearScriptCounts(Realm* realm); + void clearScriptLCov(Realm* realm); + + // Add the target of JS WeakRef to a kept-alive set maintained by GC. + // See: https://tc39.es/proposal-weakrefs/#sec-keepduringjob + bool keepDuringJob(HandleObject target); + + void traceKeptObjects(JSTracer* trc); + + // Clear the kept-alive set. + // See: https://tc39.es/proposal-weakrefs/#sec-clear-kept-objects + void clearKeptObjects(); + +#ifdef JSGC_HASH_TABLE_CHECKS + void checkAllCrossCompartmentWrappersAfterMovingGC(); + void checkStringWrappersAfterMovingGC(); + + void checkInitialShapesTableAfterMovingGC(); + void checkBaseShapeTableAfterMovingGC(); + + // Assert that the UniqueId table has been redirected successfully. + void checkUniqueIdTableAfterMovingGC(); + + void checkScriptMapsAfterMovingGC(); +#endif + +#ifdef DEBUG + // For testing purposes, return the index of the sweep group which this zone + // was swept in in the last GC. + unsigned lastSweepGroupIndex() { return gcSweepGroupIndex; } +#endif + + private: + js::jit::JitZone* createJitZone(JSContext* cx); + + bool isQueuedForBackgroundSweep() { return isOnList(); } + + void sweepWeakKeysAfterMinorGC(); + + FinalizationRegistrySet& finalizationRegistries() { + return finalizationRegistries_.ref(); + } + + FinalizationRecordMap& finalizationRecordMap() { + return finalizationRecordMap_.ref(); + } + + bool isOnList() const; + Zone* nextZone() const; + + js::WeakRefMap& weakRefMap() { return weakRefMap_.ref(); } + + friend bool js::CurrentThreadCanAccessZone(Zone* zone); + friend class js::gc::GCRuntime; +}; + +} // namespace JS + +namespace js { +namespace gc { +const char* StateName(JS::Zone::GCState state); +} // namespace gc +} // namespace js + +#endif // gc_Zone_h |