1 files changed, 798 insertions, 0 deletions
diff --git a/js/src/gc/GCAPI.cpp b/js/src/gc/GCAPI.cpp
new file mode 100644
index 0000000000..7911baaf93
--- /dev/null
+++ b/js/src/gc/GCAPI.cpp
@@ -0,0 +1,798 @@
+/* -*- 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/. */
+
+/*
+ * API functions and methods used by the rest of SpiderMonkey and by embeddings.
+ */
+
+#include "mozilla/TimeStamp.h"
+
+#include "jsapi.h"
+#include "jsfriendapi.h"
+
+#include "gc/GC.h"
+#include "gc/PublicIterators.h"
+#include "jit/JitRealm.h"
+#include "js/HeapAPI.h"
+#include "js/Value.h"
+#include "util/DifferentialTesting.h"
+#include "vm/HelperThreads.h"
+#include "vm/Realm.h"
+#include "vm/Scope.h"
+
+#include "gc/Marking-inl.h"
+#include "gc/StableCellHasher-inl.h"
+#include "vm/GeckoProfiler-inl.h"
+#include "vm/JSContext-inl.h"
+
+using namespace js;
+using namespace js::gc;
+
+using mozilla::TimeStamp;
+
+extern JS_PUBLIC_API bool js::AddRawValueRoot(JSContext* cx, Value* vp,
+                                              const char* name) {
+  MOZ_ASSERT(vp);
+  MOZ_ASSERT(name);
+  bool ok = cx->runtime()->gc.addRoot(vp, name);
+  if (!ok) {
+    JS_ReportOutOfMemory(cx);
+  }
+  return ok;
+}
+
+extern JS_PUBLIC_API void js::RemoveRawValueRoot(JSContext* cx, Value* vp) {
+  cx->runtime()->gc.removeRoot(vp);
+}
+
+JS_PUBLIC_API JS::HeapState JS::RuntimeHeapState() {
+  return TlsContext.get()->runtime()->gc.heapState();
+}
+
+JS::AutoDisableGenerationalGC::AutoDisableGenerationalGC(JSContext* cx)
+    : cx(cx) {
+  if (!cx->generationalDisabled) {
+    cx->runtime()->gc.evictNursery(JS::GCReason::DISABLE_GENERATIONAL_GC);
+    cx->nursery().disable();
+  }
+  ++cx->generationalDisabled;
+  MOZ_ASSERT(cx->nursery().isEmpty());
+}
+
+JS::AutoDisableGenerationalGC::~AutoDisableGenerationalGC() {
+  if (--cx->generationalDisabled == 0 &&
+      cx->runtime()->gc.tunables.gcMaxNurseryBytes() > 0) {
+    cx->nursery().enable();
+  }
+}
+
+JS_PUBLIC_API bool JS::IsGenerationalGCEnabled(JSRuntime* rt) {
+  return !rt->mainContextFromOwnThread()->generationalDisabled;
+}
+
+AutoDisableCompactingGC::AutoDisableCompactingGC(JSContext* cx) : cx(cx) {
+  ++cx->compactingDisabledCount;
+  if (cx->runtime()->gc.isIncrementalGCInProgress() &&
+      cx->runtime()->gc.isCompactingGc()) {
+    FinishGC(cx);
+  }
+}
+
+AutoDisableCompactingGC::~AutoDisableCompactingGC() {
+  MOZ_ASSERT(cx->compactingDisabledCount > 0);
+  --cx->compactingDisabledCount;
+}
+
+#ifdef DEBUG
+
+/* Should only be called manually under gdb */
+void PreventGCDuringInteractiveDebug() { TlsContext.get()->suppressGC++; }
+
+#endif
+
+void js::ReleaseAllJITCode(JS::GCContext* gcx) {
+  js::CancelOffThreadIonCompile(gcx->runtime());
+
+  for (ZonesIter zone(gcx->runtime(), SkipAtoms); !zone.done(); zone.next()) {
+    zone->forceDiscardJitCode(gcx);
+  }
+
+  for (RealmsIter realm(gcx->runtime()); !realm.done(); realm.next()) {
+    if (jit::JitRealm* jitRealm = realm->jitRealm()) {
+      jitRealm->discardStubs();
+    }
+  }
+}
+
+AutoSuppressGC::AutoSuppressGC(JSContext* cx)
+    : suppressGC_(cx->suppressGC.ref()) {
+  suppressGC_++;
+}
+
+#ifdef DEBUG
+AutoDisableProxyCheck::AutoDisableProxyCheck() {
+  TlsContext.get()->disableStrictProxyChecking();
+}
+
+AutoDisableProxyCheck::~AutoDisableProxyCheck() {
+  TlsContext.get()->enableStrictProxyChecking();
+}
+
+JS_PUBLIC_API void JS::AssertGCThingMustBeTenured(JSObject* obj) {
+  MOZ_ASSERT(obj->isTenured());
+  MOZ_ASSERT(obj->getClass()->hasFinalize() &&
+             !(obj->getClass()->flags & JSCLASS_SKIP_NURSERY_FINALIZE));
+}
+
+JS_PUBLIC_API void JS::AssertGCThingIsNotNurseryAllocable(Cell* cell) {
+  MOZ_ASSERT(cell);
+  MOZ_ASSERT(!cell->is<JSObject>() && !cell->is<JSString>() &&
+             !cell->is<JS::BigInt>());
+}
+
+JS_PUBLIC_API void js::gc::AssertGCThingHasType(js::gc::Cell* cell,
+                                                JS::TraceKind kind) {
+  if (!cell) {
+    MOZ_ASSERT(kind == JS::TraceKind::Null);
+    return;
+  }
+
+  MOZ_ASSERT(IsCellPointerValid(cell));
+  MOZ_ASSERT(cell->getTraceKind() == kind);
+}
+#endif
+
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+JS::AutoAssertNoGC::AutoAssertNoGC(JSContext* maybecx) {
+  if (maybecx) {
+    cx_ = maybecx;
+  } else if (TlsContext.initialized()) {
+    cx_ = TlsContext.get();
+  } else {
+    cx_ = nullptr;
+  }
+  if (cx_) {
+    cx_->inUnsafeRegion++;
+  }
+}
+
+JS::AutoAssertNoGC::~AutoAssertNoGC() {
+  if (cx_) {
+    MOZ_ASSERT(cx_->inUnsafeRegion > 0);
+    cx_->inUnsafeRegion--;
+  }
+}
+
+#endif  // MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+#ifdef DEBUG
+
+JS::AutoEnterCycleCollection::AutoEnterCycleCollection(JSRuntime* rt)
+    : runtime_(rt) {
+  MOZ_ASSERT(CurrentThreadCanAccessRuntime(rt));
+  MOZ_ASSERT(!JS::RuntimeHeapIsBusy());
+  runtime_->gc.heapState_ = HeapState::CycleCollecting;
+}
+
+JS::AutoEnterCycleCollection::~AutoEnterCycleCollection() {
+  MOZ_ASSERT(JS::RuntimeHeapIsCycleCollecting());
+  runtime_->gc.heapState_ = HeapState::Idle;
+}
+
+JS::AutoAssertGCCallback::AutoAssertGCCallback() : AutoSuppressGCAnalysis() {
+  MOZ_ASSERT(JS::RuntimeHeapIsCollecting());
+}
+
+#endif  // DEBUG
+
+JS_PUBLIC_API const char* JS::GCTraceKindToAscii(JS::TraceKind kind) {
+  switch (kind) {
+#define MAP_NAME(name, _0, _1, _2) \
+  case JS::TraceKind::name:        \
+    return "JS " #name;
+    JS_FOR_EACH_TRACEKIND(MAP_NAME);
+#undef MAP_NAME
+    default:
+      return "Invalid";
+  }
+}
+
+JS_PUBLIC_API size_t JS::GCTraceKindSize(JS::TraceKind kind) {
+  switch (kind) {
+#define MAP_SIZE(name, type, _0, _1) \
+  case JS::TraceKind::name:          \
+    return sizeof(type);
+    JS_FOR_EACH_TRACEKIND(MAP_SIZE);
+#undef MAP_SIZE
+    default:
+      return 0;
+  }
+}
+
+JS::GCCellPtr::GCCellPtr(const Value& v)
+    : GCCellPtr(v.toGCThing(), v.traceKind()) {}
+
+JS::TraceKind JS::GCCellPtr::outOfLineKind() const {
+  MOZ_ASSERT((ptr & OutOfLineTraceKindMask) == OutOfLineTraceKindMask);
+  MOZ_ASSERT(asCell()->isTenured());
+  return MapAllocToTraceKind(asCell()->asTenured().getAllocKind());
+}
+
+JS_PUBLIC_API void JS::PrepareZoneForGC(JSContext* cx, Zone* zone) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  // If we got the zone from a shared atom, we may have the wrong atoms zone
+  // here.
+  if (zone->isAtomsZone()) {
+    zone = cx->runtime()->atomsZone();
+  }
+
+  MOZ_ASSERT(cx->runtime()->gc.hasZone(zone));
+  zone->scheduleGC();
+}
+
+JS_PUBLIC_API void JS::PrepareForFullGC(JSContext* cx) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  cx->runtime()->gc.fullGCRequested = true;
+  for (ZonesIter zone(cx->runtime(), WithAtoms); !zone.done(); zone.next()) {
+    zone->scheduleGC();
+  }
+}
+
+JS_PUBLIC_API void JS::PrepareForIncrementalGC(JSContext* cx) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  if (!JS::IsIncrementalGCInProgress(cx)) {
+    return;
+  }
+
+  for (ZonesIter zone(cx->runtime(), WithAtoms); !zone.done(); zone.next()) {
+    if (zone->wasGCStarted()) {
+      zone->scheduleGC();
+    }
+  }
+}
+
+JS_PUBLIC_API bool JS::IsGCScheduled(JSContext* cx) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  for (ZonesIter zone(cx->runtime(), WithAtoms); !zone.done(); zone.next()) {
+    if (zone->isGCScheduled()) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+JS_PUBLIC_API void JS::SkipZoneForGC(JSContext* cx, Zone* zone) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  MOZ_ASSERT(cx->runtime()->gc.hasZone(zone));
+
+  cx->runtime()->gc.fullGCRequested = false;
+  zone->unscheduleGC();
+}
+
+static inline void CheckGCOptions(JS::GCOptions options) {
+  MOZ_ASSERT(options == JS::GCOptions::Normal ||
+             options == JS::GCOptions::Shrink ||
+             options == JS::GCOptions::Shutdown);
+}
+
+JS_PUBLIC_API void JS::NonIncrementalGC(JSContext* cx, JS::GCOptions options,
+                                        GCReason reason) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  CheckGCOptions(options);
+
+  cx->runtime()->gc.gc(options, reason);
+
+  MOZ_ASSERT(!IsIncrementalGCInProgress(cx));
+}
+
+JS_PUBLIC_API void JS::StartIncrementalGC(JSContext* cx, JS::GCOptions options,
+                                          GCReason reason,
+                                          const js::SliceBudget& budget) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  CheckGCOptions(options);
+
+  cx->runtime()->gc.startGC(options, reason, budget);
+}
+
+JS_PUBLIC_API void JS::IncrementalGCSlice(JSContext* cx, GCReason reason,
+                                          const js::SliceBudget& budget) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  cx->runtime()->gc.gcSlice(reason, budget);
+}
+
+JS_PUBLIC_API bool JS::IncrementalGCHasForegroundWork(JSContext* cx) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  return cx->runtime()->gc.hasForegroundWork();
+}
+
+JS_PUBLIC_API void JS::FinishIncrementalGC(JSContext* cx, GCReason reason) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  cx->runtime()->gc.finishGC(reason);
+}
+
+JS_PUBLIC_API void JS::AbortIncrementalGC(JSContext* cx) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  if (IsIncrementalGCInProgress(cx)) {
+    cx->runtime()->gc.abortGC();
+  }
+}
+
+char16_t* JS::GCDescription::formatSliceMessage(JSContext* cx) const {
+  UniqueChars cstr = cx->runtime()->gc.stats().formatCompactSliceMessage();
+
+  size_t nchars = strlen(cstr.get());
+  UniqueTwoByteChars out(js_pod_malloc<char16_t>(nchars + 1));
+  if (!out) {
+    return nullptr;
+  }
+  out.get()[nchars] = 0;
+
+  CopyAndInflateChars(out.get(), cstr.get(), nchars);
+  return out.release();
+}
+
+char16_t* JS::GCDescription::formatSummaryMessage(JSContext* cx) const {
+  UniqueChars cstr = cx->runtime()->gc.stats().formatCompactSummaryMessage();
+
+  size_t nchars = strlen(cstr.get());
+  UniqueTwoByteChars out(js_pod_malloc<char16_t>(nchars + 1));
+  if (!out) {
+    return nullptr;
+  }
+  out.get()[nchars] = 0;
+
+  CopyAndInflateChars(out.get(), cstr.get(), nchars);
+  return out.release();
+}
+
+JS::dbg::GarbageCollectionEvent::Ptr JS::GCDescription::toGCEvent(
+    JSContext* cx) const {
+  return JS::dbg::GarbageCollectionEvent::Create(
+      cx->runtime(), cx->runtime()->gc.stats(),
+      cx->runtime()->gc.majorGCCount());
+}
+
+TimeStamp JS::GCDescription::startTime(JSContext* cx) const {
+  return cx->runtime()->gc.stats().start();
+}
+
+TimeStamp JS::GCDescription::endTime(JSContext* cx) const {
+  return cx->runtime()->gc.stats().end();
+}
+
+TimeStamp JS::GCDescription::lastSliceStart(JSContext* cx) const {
+  return cx->runtime()->gc.stats().slices().back().start;
+}
+
+TimeStamp JS::GCDescription::lastSliceEnd(JSContext* cx) const {
+  return cx->runtime()->gc.stats().slices().back().end;
+}
+
+JS::UniqueChars JS::GCDescription::sliceToJSONProfiler(JSContext* cx) const {
+  size_t slices = cx->runtime()->gc.stats().slices().length();
+  MOZ_ASSERT(slices > 0);
+  return cx->runtime()->gc.stats().renderJsonSlice(slices - 1);
+}
+
+JS::UniqueChars JS::GCDescription::formatJSONProfiler(JSContext* cx) const {
+  return cx->runtime()->gc.stats().renderJsonMessage();
+}
+
+JS_PUBLIC_API JS::UniqueChars JS::MinorGcToJSON(JSContext* cx) {
+  JSRuntime* rt = cx->runtime();
+  return rt->gc.stats().renderNurseryJson();
+}
+
+JS_PUBLIC_API JS::GCSliceCallback JS::SetGCSliceCallback(
+    JSContext* cx, GCSliceCallback callback) {
+  return cx->runtime()->gc.setSliceCallback(callback);
+}
+
+JS_PUBLIC_API JS::DoCycleCollectionCallback JS::SetDoCycleCollectionCallback(
+    JSContext* cx, JS::DoCycleCollectionCallback callback) {
+  return cx->runtime()->gc.setDoCycleCollectionCallback(callback);
+}
+
+JS_PUBLIC_API JS::GCNurseryCollectionCallback
+JS::SetGCNurseryCollectionCallback(JSContext* cx,
+                                   GCNurseryCollectionCallback callback) {
+  return cx->runtime()->gc.setNurseryCollectionCallback(callback);
+}
+
+JS_PUBLIC_API void JS::SetLowMemoryState(JSContext* cx, bool newState) {
+  return cx->runtime()->gc.setLowMemoryState(newState);
+}
+
+JS_PUBLIC_API void JS::DisableIncrementalGC(JSContext* cx) {
+  cx->runtime()->gc.disallowIncrementalGC();
+}
+
+JS_PUBLIC_API bool JS::IsIncrementalGCEnabled(JSContext* cx) {
+  GCRuntime& gc = cx->runtime()->gc;
+  return gc.isIncrementalGCEnabled() && gc.isIncrementalGCAllowed();
+}
+
+JS_PUBLIC_API bool JS::IsIncrementalGCInProgress(JSContext* cx) {
+  return cx->runtime()->gc.isIncrementalGCInProgress();
+}
+
+JS_PUBLIC_API bool JS::IsIncrementalGCInProgress(JSRuntime* rt) {
+  return rt->gc.isIncrementalGCInProgress() &&
+         !rt->gc.isVerifyPreBarriersEnabled();
+}
+
+JS_PUBLIC_API bool JS::IsIncrementalBarrierNeeded(JSContext* cx) {
+  if (JS::RuntimeHeapIsBusy()) {
+    return false;
+  }
+
+  auto state = cx->runtime()->gc.state();
+  return state != gc::State::NotActive && state <= gc::State::Sweep;
+}
+
+JS_PUBLIC_API void JS::IncrementalPreWriteBarrier(JSObject* obj) {
+  if (!obj) {
+    return;
+  }
+
+  AutoGeckoProfilerEntry profilingStackFrame(
+      TlsContext.get(), "IncrementalPreWriteBarrier(JSObject*)",
+      JS::ProfilingCategoryPair::GCCC_Barrier);
+  PreWriteBarrier(obj);
+}
+
+JS_PUBLIC_API void JS::IncrementalPreWriteBarrier(GCCellPtr thing) {
+  if (!thing) {
+    return;
+  }
+
+  AutoGeckoProfilerEntry profilingStackFrame(
+      TlsContext.get(), "IncrementalPreWriteBarrier(GCCellPtr)",
+      JS::ProfilingCategoryPair::GCCC_Barrier);
+  CellPtrPreWriteBarrier(thing);
+}
+
+JS_PUBLIC_API bool JS::WasIncrementalGC(JSRuntime* rt) {
+  return rt->gc.isIncrementalGc();
+}
+
+bool js::gc::CreateUniqueIdForNativeObject(NativeObject* nobj, uint64_t* uidp) {
+  JSRuntime* runtime = nobj->runtimeFromMainThread();
+  *uidp = NextCellUniqueId(runtime);
+  JSContext* cx = runtime->mainContextFromOwnThread();
+  return nobj->setUniqueId(cx, *uidp);
+}
+
+bool js::gc::CreateUniqueIdForNonNativeObject(Cell* cell,
+                                              UniqueIdMap::AddPtr ptr,
+                                              uint64_t* uidp) {
+  // If the cell is in the nursery, hopefully unlikely, then we need to tell the
+  // nursery about it so that it can sweep the uid if the thing does not get
+  // tenured.
+  JSRuntime* runtime = cell->runtimeFromMainThread();
+  if (IsInsideNursery(cell) &&
+      !runtime->gc.nursery().addedUniqueIdToCell(cell)) {
+    return false;
+  }
+
+  // Set a new uid on the cell.
+  *uidp = NextCellUniqueId(runtime);
+  return cell->zone()->uniqueIds().add(ptr, cell, *uidp);
+}
+
+uint64_t js::gc::NextCellUniqueId(JSRuntime* rt) {
+  return rt->gc.nextCellUniqueId();
+}
+
+namespace js {
+
+static const struct GCParamInfo {
+  const char* name;
+  JSGCParamKey key;
+  bool writable;
+} GCParameters[] = {
+#define DEFINE_PARAM_INFO(name, key, writable) {name, key, writable},
+    FOR_EACH_GC_PARAM(DEFINE_PARAM_INFO)
+#undef DEFINE_PARAM_INFO
+};
+
+bool GetGCParameterInfo(const char* name, JSGCParamKey* keyOut,
+                        bool* writableOut) {
+  MOZ_ASSERT(keyOut);
+  MOZ_ASSERT(writableOut);
+
+  for (const GCParamInfo& info : GCParameters) {
+    if (strcmp(name, info.name) == 0) {
+      *keyOut = info.key;
+      *writableOut = info.writable;
+      return true;
+    }
+  }
+
+  return false;
+}
+
+namespace gc {
+namespace MemInfo {
+
+static bool GCBytesGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->runtime()->gc.heapSize.bytes()));
+  return true;
+}
+
+static bool MallocBytesGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  double bytes = 0;
+  for (ZonesIter zone(cx->runtime(), WithAtoms); !zone.done(); zone.next()) {
+    bytes += zone->mallocHeapSize.bytes();
+  }
+  args.rval().setNumber(bytes);
+  return true;
+}
+
+static bool GCMaxBytesGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->runtime()->gc.tunables.gcMaxBytes()));
+  return true;
+}
+
+static bool GCHighFreqGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setBoolean(
+      cx->runtime()->gc.schedulingState.inHighFrequencyGCMode());
+  return true;
+}
+
+static bool GCNumberGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->runtime()->gc.gcNumber()));
+  return true;
+}
+
+static bool MajorGCCountGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->runtime()->gc.majorGCCount()));
+  return true;
+}
+
+static bool MinorGCCountGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->runtime()->gc.minorGCCount()));
+  return true;
+}
+
+static bool GCSliceCountGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->runtime()->gc.gcSliceCount()));
+  return true;
+}
+
+static bool GCCompartmentCount(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  size_t count = 0;
+  for (ZonesIter zone(cx->runtime(), WithAtoms); !zone.done(); zone.next()) {
+    count += zone->compartments().length();
+  }
+
+  args.rval().setNumber(double(count));
+  return true;
+}
+
+static bool GCLastStartReason(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  const char* reason = ExplainGCReason(cx->runtime()->gc.lastStartReason());
+  RootedString str(cx, JS_NewStringCopyZ(cx, reason));
+  if (!str) {
+    return false;
+  }
+
+  args.rval().setString(str);
+  return true;
+}
+
+static bool ZoneGCBytesGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->zone()->gcHeapSize.bytes()));
+  return true;
+}
+
+static bool ZoneGCTriggerBytesGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->zone()->gcHeapThreshold.startBytes()));
+  return true;
+}
+
+static bool ZoneGCAllocTriggerGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  bool highFrequency =
+      cx->runtime()->gc.schedulingState.inHighFrequencyGCMode();
+  args.rval().setNumber(
+      double(cx->zone()->gcHeapThreshold.eagerAllocTrigger(highFrequency)));
+  return true;
+}
+
+static bool ZoneMallocBytesGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->zone()->mallocHeapSize.bytes()));
+  return true;
+}
+
+static bool ZoneMallocTriggerBytesGetter(JSContext* cx, unsigned argc,
+                                         Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->zone()->mallocHeapThreshold.startBytes()));
+  return true;
+}
+
+static bool ZoneGCNumberGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setNumber(double(cx->runtime()->gc.gcNumber()));
+  return true;
+}
+
+#ifdef DEBUG
+static bool DummyGetter(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setUndefined();
+  return true;
+}
+#endif
+
+} /* namespace MemInfo */
+
+JSObject* NewMemoryInfoObject(JSContext* cx) {
+  RootedObject obj(cx, JS_NewObject(cx, nullptr));
+  if (!obj) {
+    return nullptr;
+  }
+
+  using namespace MemInfo;
+  struct NamedGetter {
+    const char* name;
+    JSNative getter;
+  } getters[] = {{"gcBytes", GCBytesGetter},
+                 {"gcMaxBytes", GCMaxBytesGetter},
+                 {"mallocBytes", MallocBytesGetter},
+                 {"gcIsHighFrequencyMode", GCHighFreqGetter},
+                 {"gcNumber", GCNumberGetter},
+                 {"majorGCCount", MajorGCCountGetter},
+                 {"minorGCCount", MinorGCCountGetter},
+                 {"sliceCount", GCSliceCountGetter},
+                 {"compartmentCount", GCCompartmentCount},
+                 {"lastStartReason", GCLastStartReason}};
+
+  for (auto pair : getters) {
+    JSNative getter = pair.getter;
+
+#ifdef DEBUG
+    if (js::SupportDifferentialTesting()) {
+      getter = DummyGetter;
+    }
+#endif
+
+    if (!JS_DefineProperty(cx, obj, pair.name, getter, nullptr,
+                           JSPROP_ENUMERATE)) {
+      return nullptr;
+    }
+  }
+
+  RootedObject zoneObj(cx, JS_NewObject(cx, nullptr));
+  if (!zoneObj) {
+    return nullptr;
+  }
+
+  if (!JS_DefineProperty(cx, obj, "zone", zoneObj, JSPROP_ENUMERATE)) {
+    return nullptr;
+  }
+
+  struct NamedZoneGetter {
+    const char* name;
+    JSNative getter;
+  } zoneGetters[] = {{"gcBytes", ZoneGCBytesGetter},
+                     {"gcTriggerBytes", ZoneGCTriggerBytesGetter},
+                     {"gcAllocTrigger", ZoneGCAllocTriggerGetter},
+                     {"mallocBytes", ZoneMallocBytesGetter},
+                     {"mallocTriggerBytes", ZoneMallocTriggerBytesGetter},
+                     {"gcNumber", ZoneGCNumberGetter}};
+
+  for (auto pair : zoneGetters) {
+    JSNative getter = pair.getter;
+
+#ifdef DEBUG
+    if (js::SupportDifferentialTesting()) {
+      getter = DummyGetter;
+    }
+#endif
+
+    if (!JS_DefineProperty(cx, zoneObj, pair.name, getter, nullptr,
+                           JSPROP_ENUMERATE)) {
+      return nullptr;
+    }
+  }
+
+  return obj;
+}
+
+const char* StateName(State state) {
+  switch (state) {
+#define MAKE_CASE(name) \
+  case State::name:     \
+    return #name;
+    GCSTATES(MAKE_CASE)
+#undef MAKE_CASE
+  }
+  MOZ_CRASH("Invalid gc::State enum value");
+}
+
+const char* StateName(JS::Zone::GCState state) {
+  switch (state) {
+    case JS::Zone::NoGC:
+      return "NoGC";
+    case JS::Zone::Prepare:
+      return "Prepare";
+    case JS::Zone::MarkBlackOnly:
+      return "MarkBlackOnly";
+    case JS::Zone::MarkBlackAndGray:
+      return "MarkBlackAndGray";
+    case JS::Zone::Sweep:
+      return "Sweep";
+    case JS::Zone::Finished:
+      return "Finished";
+    case JS::Zone::Compact:
+      return "Compact";
+    case JS::Zone::VerifyPreBarriers:
+      return "VerifyPreBarriers";
+    case JS::Zone::Limit:
+      break;
+  }
+  MOZ_CRASH("Invalid Zone::GCState enum value");
+}
+
+} /* namespace gc */
+} /* namespace js */
+
+JS_PUBLIC_API void js::gc::FinalizeDeadNurseryObject(JSContext* cx,
+                                                     JSObject* obj) {
+  CHECK_THREAD(cx);
+  MOZ_ASSERT(JS::RuntimeHeapIsMinorCollecting());
+
+  MOZ_ASSERT(obj);
+  MOZ_ASSERT(IsInsideNursery(obj));
+  MOZ_ASSERT(!IsForwarded(obj));
+
+  const JSClass* jsClass = JS::GetClass(obj);
+  jsClass->doFinalize(cx->gcContext(), obj);
+}
+
+JS_PUBLIC_API void js::gc::SetPerformanceHint(JSContext* cx,
+                                              PerformanceHint hint) {
+  CHECK_THREAD(cx);
+  MOZ_ASSERT(!JS::RuntimeHeapIsCollecting());
+
+  cx->runtime()->gc.setPerformanceHint(hint);
+}