Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 979 insertions, 0 deletions

diff --git a/js/src/gc/Zone.cpp b/js/src/gc/Zone.cpp
new file mode 100644
index 0000000000..982b12f17f
--- /dev/null
+++ b/js/src/gc/Zone.cpp
@@ -0,0 +1,979 @@
+/* -*- 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/. */
+
+#include "gc/Zone.h"
+#include "js/shadow/Zone.h"  // JS::shadow::Zone
+
+#include "mozilla/Sprintf.h"
+#include "mozilla/TimeStamp.h"
+
+#include <type_traits>
+
+#include "gc/FinalizationObservers.h"
+#include "gc/GCContext.h"
+#include "gc/PublicIterators.h"
+#include "jit/BaselineIC.h"
+#include "jit/BaselineJIT.h"
+#include "jit/Invalidation.h"
+#include "jit/JitZone.h"
+#include "vm/Runtime.h"
+#include "vm/Time.h"
+
+#include "debugger/DebugAPI-inl.h"
+#include "gc/GC-inl.h"
+#include "gc/Marking-inl.h"
+#include "gc/Nursery-inl.h"
+#include "gc/WeakMap-inl.h"
+#include "vm/JSScript-inl.h"
+#include "vm/Realm-inl.h"
+
+using namespace js;
+using namespace js::gc;
+
+Zone* const Zone::NotOnList = reinterpret_cast<Zone*>(1);
+
+ZoneAllocator::ZoneAllocator(JSRuntime* rt, Kind kind)
+    : JS::shadow::Zone(rt, rt->gc.marker().tracer(), kind),
+      jitHeapThreshold(jit::MaxCodeBytesPerProcess * 0.8) {}
+
+ZoneAllocator::~ZoneAllocator() {
+#ifdef DEBUG
+  mallocTracker.checkEmptyOnDestroy();
+  MOZ_ASSERT(gcHeapSize.bytes() == 0);
+  MOZ_ASSERT(mallocHeapSize.bytes() == 0);
+  MOZ_ASSERT(jitHeapSize.bytes() == 0);
+#endif
+}
+
+void ZoneAllocator::fixupAfterMovingGC() {
+#ifdef DEBUG
+  mallocTracker.fixupAfterMovingGC();
+#endif
+}
+
+void js::ZoneAllocator::updateSchedulingStateOnGCStart() {
+  gcHeapSize.updateOnGCStart();
+  mallocHeapSize.updateOnGCStart();
+  jitHeapSize.updateOnGCStart();
+  perZoneGCTime = mozilla::TimeDuration();
+}
+
+void js::ZoneAllocator::updateGCStartThresholds(GCRuntime& gc) {
+  bool isAtomsZone = JS::Zone::from(this)->isAtomsZone();
+  gcHeapThreshold.updateStartThreshold(
+      gcHeapSize.retainedBytes(), smoothedAllocationRate.ref(),
+      smoothedCollectionRate.ref(), gc.tunables, gc.schedulingState,
+      isAtomsZone);
+
+  mallocHeapThreshold.updateStartThreshold(mallocHeapSize.retainedBytes(),
+                                           gc.tunables, gc.schedulingState);
+}
+
+void js::ZoneAllocator::setGCSliceThresholds(GCRuntime& gc,
+                                             bool waitingOnBGTask) {
+  gcHeapThreshold.setSliceThreshold(this, gcHeapSize, gc.tunables,
+                                    waitingOnBGTask);
+  mallocHeapThreshold.setSliceThreshold(this, mallocHeapSize, gc.tunables,
+                                        waitingOnBGTask);
+  jitHeapThreshold.setSliceThreshold(this, jitHeapSize, gc.tunables,
+                                     waitingOnBGTask);
+}
+
+void js::ZoneAllocator::clearGCSliceThresholds() {
+  gcHeapThreshold.clearSliceThreshold();
+  mallocHeapThreshold.clearSliceThreshold();
+  jitHeapThreshold.clearSliceThreshold();
+}
+
+bool ZoneAllocator::addSharedMemory(void* mem, size_t nbytes, MemoryUse use) {
+  // nbytes can be zero here for SharedArrayBuffers.
+
+  MOZ_ASSERT(CurrentThreadCanAccessRuntime(runtime_));
+
+  auto ptr = sharedMemoryUseCounts.lookupForAdd(mem);
+  MOZ_ASSERT_IF(ptr, ptr->value().use == use);
+
+  if (!ptr && !sharedMemoryUseCounts.add(ptr, mem, gc::SharedMemoryUse(use))) {
+    return false;
+  }
+
+  ptr->value().count++;
+
+  // Allocations can grow, so add any increase over the previous size and record
+  // the new size.
+  if (nbytes > ptr->value().nbytes) {
+    mallocHeapSize.addBytes(nbytes - ptr->value().nbytes);
+    ptr->value().nbytes = nbytes;
+  }
+
+  maybeTriggerGCOnMalloc();
+
+  return true;
+}
+
+void ZoneAllocator::removeSharedMemory(void* mem, size_t nbytes,
+                                       MemoryUse use) {
+  // nbytes can be zero here for SharedArrayBuffers.
+
+  MOZ_ASSERT(CurrentThreadCanAccessRuntime(runtime_));
+  MOZ_ASSERT(CurrentThreadIsGCFinalizing());
+
+  auto ptr = sharedMemoryUseCounts.lookup(mem);
+
+  MOZ_ASSERT(ptr);
+  MOZ_ASSERT(ptr->value().count != 0);
+  MOZ_ASSERT(ptr->value().use == use);
+  MOZ_ASSERT(ptr->value().nbytes >= nbytes);
+
+  ptr->value().count--;
+  if (ptr->value().count == 0) {
+    mallocHeapSize.removeBytes(ptr->value().nbytes, true);
+    sharedMemoryUseCounts.remove(ptr);
+  }
+}
+
+template <TrackingKind kind>
+void js::TrackedAllocPolicy<kind>::decMemory(size_t nbytes) {
+  bool updateRetainedSize = false;
+  if constexpr (kind == TrackingKind::Cell) {
+    // Only subtract freed cell memory from retained size for cell associations
+    // during sweeping.
+    JS::GCContext* gcx = TlsGCContext.get();
+    updateRetainedSize = gcx->isFinalizing();
+  }
+
+  zone_->decNonGCMemory(this, nbytes, MemoryUse::TrackedAllocPolicy,
+                        updateRetainedSize);
+}
+
+namespace js {
+template class TrackedAllocPolicy<TrackingKind::Zone>;
+template class TrackedAllocPolicy<TrackingKind::Cell>;
+}  // namespace js
+
+JS::Zone::Zone(JSRuntime* rt, Kind kind)
+    : ZoneAllocator(rt, kind),
+      arenas(this),
+      data(nullptr),
+      tenuredBigInts(0),
+      markedStrings(0),
+      finalizedStrings(0),
+      suppressAllocationMetadataBuilder(false),
+      allocNurseryObjects_(true),
+      allocNurseryStrings_(true),
+      allocNurseryBigInts_(true),
+      pretenuring(this),
+      compartments_(),
+      crossZoneStringWrappers_(this),
+      gcEphemeronEdges_(SystemAllocPolicy(), rt->randomHashCodeScrambler()),
+      gcNurseryEphemeronEdges_(SystemAllocPolicy(),
+                               rt->randomHashCodeScrambler()),
+      shapeZone_(this),
+      gcScheduled_(false),
+      gcScheduledSaved_(false),
+      gcPreserveCode_(false),
+      keepPropMapTables_(false),
+      wasCollected_(false),
+      listNext_(NotOnList),
+      keptObjects(this) {
+  /* Ensure that there are no vtables to mess us up here. */
+  MOZ_ASSERT(reinterpret_cast<JS::shadow::Zone*>(this) ==
+             static_cast<JS::shadow::Zone*>(this));
+  MOZ_ASSERT_IF(isAtomsZone(), rt->gc.zones().empty());
+
+  updateGCStartThresholds(rt->gc);
+  rt->gc.nursery().setAllocFlagsForZone(this);
+}
+
+Zone::~Zone() {
+  MOZ_ASSERT_IF(regExps_.ref(), regExps().empty());
+
+  DebugAPI::deleteDebugScriptMap(debugScriptMap);
+  js_delete(finalizationObservers_.ref().release());
+
+  MOZ_ASSERT(gcWeakMapList().isEmpty());
+
+  JSRuntime* rt = runtimeFromAnyThread();
+  if (this == rt->gc.systemZone) {
+    MOZ_ASSERT(isSystemZone());
+    rt->gc.systemZone = nullptr;
+  }
+
+  js_delete(jitZone_.ref());
+}
+
+bool Zone::init() {
+  regExps_.ref() = make_unique<RegExpZone>(this);
+  return regExps_.ref() && gcEphemeronEdges().init() &&
+         gcNurseryEphemeronEdges().init();
+}
+
+void Zone::setNeedsIncrementalBarrier(bool needs) {
+  needsIncrementalBarrier_ = needs;
+}
+
+void Zone::changeGCState(GCState prev, GCState next) {
+  MOZ_ASSERT(RuntimeHeapIsBusy());
+  MOZ_ASSERT(gcState() == prev);
+
+  // This can be called when barriers have been temporarily disabled by
+  // AutoDisableBarriers. In that case, don't update needsIncrementalBarrier_
+  // and barriers will be re-enabled by ~AutoDisableBarriers() if necessary.
+  bool barriersDisabled = isGCMarking() && !needsIncrementalBarrier();
+
+  gcState_ = next;
+
+  // Update the barriers state when we transition between marking and
+  // non-marking states, unless barriers have been disabled.
+  if (!barriersDisabled) {
+    needsIncrementalBarrier_ = isGCMarking();
+  }
+}
+
+template <class Pred>
+static void EraseIf(js::gc::EphemeronEdgeVector& entries, Pred pred) {
+  auto* begin = entries.begin();
+  auto* const end = entries.end();
+
+  auto* newEnd = begin;
+  for (auto* p = begin; p != end; p++) {
+    if (!pred(*p)) {
+      *newEnd++ = *p;
+    }
+  }
+
+  size_t removed = end - newEnd;
+  entries.shrinkBy(removed);
+}
+
+static void SweepEphemeronEdgesWhileMinorSweeping(
+    js::gc::EphemeronEdgeVector& entries) {
+  EraseIf(entries, [](js::gc::EphemeronEdge& edge) -> bool {
+    return IsAboutToBeFinalizedDuringMinorSweep(&edge.target);
+  });
+}
+
+void Zone::sweepAfterMinorGC(JSTracer* trc) {
+  sweepEphemeronTablesAfterMinorGC();
+  crossZoneStringWrappers().sweepAfterMinorGC(trc);
+
+  for (CompartmentsInZoneIter comp(this); !comp.done(); comp.next()) {
+    comp->sweepAfterMinorGC(trc);
+  }
+}
+
+void Zone::sweepEphemeronTablesAfterMinorGC() {
+  for (auto r = gcNurseryEphemeronEdges().mutableAll(); !r.empty();
+       r.popFront()) {
+    // Sweep gcNurseryEphemeronEdges to move live (forwarded) keys to
+    // gcEphemeronEdges, scanning through all the entries for such keys to
+    // update them.
+    //
+    // Forwarded and dead keys may also appear in their delegates' entries,
+    // so sweep those too (see below.)
+
+    // The tricky case is when the key has a delegate that was already
+    // tenured. Then it will be in its compartment's gcEphemeronEdges, but we
+    // still need to update the key (which will be in the entries
+    // associated with it.)
+    gc::Cell* key = r.front().key;
+    MOZ_ASSERT(!key->isTenured());
+    if (!Nursery::getForwardedPointer(&key)) {
+      // Dead nursery cell => discard.
+      continue;
+    }
+
+    // Key been moved. The value is an array of <color,cell> pairs; update all
+    // cells in that array.
+    EphemeronEdgeVector& entries = r.front().value;
+    SweepEphemeronEdgesWhileMinorSweeping(entries);
+
+    // Live (moved) nursery cell. Append entries to gcEphemeronEdges.
+    EphemeronEdgeTable& tenuredEdges = gcEphemeronEdges();
+    auto* entry = tenuredEdges.get(key);
+    if (!entry) {
+      if (!tenuredEdges.put(key, gc::EphemeronEdgeVector())) {
+        AutoEnterOOMUnsafeRegion oomUnsafe;
+        oomUnsafe.crash("Failed to tenure weak keys entry");
+      }
+      entry = tenuredEdges.get(key);
+    }
+
+    if (!entry->value.appendAll(entries)) {
+      AutoEnterOOMUnsafeRegion oomUnsafe;
+      oomUnsafe.crash("Failed to tenure weak keys entry");
+    }
+
+    // If the key has a delegate, then it will map to a WeakKeyEntryVector
+    // containing the key that needs to be updated.
+
+    JSObject* delegate = gc::detail::GetDelegate(key->as<JSObject>());
+    if (!delegate) {
+      continue;
+    }
+    MOZ_ASSERT(delegate->isTenured());
+
+    // If delegate was formerly nursery-allocated, we will sweep its entries
+    // when we visit its gcNurseryEphemeronEdges (if we haven't already). Note
+    // that we don't know the nursery address of the delegate, since the
+    // location it was stored in has already been updated.
+    //
+    // Otherwise, it will be in gcEphemeronEdges and we sweep it here.
+    auto* p = delegate->zone()->gcEphemeronEdges().get(delegate);
+    if (p) {
+      SweepEphemeronEdgesWhileMinorSweeping(p->value);
+    }
+  }
+
+  if (!gcNurseryEphemeronEdges().clear()) {
+    AutoEnterOOMUnsafeRegion oomUnsafe;
+    oomUnsafe.crash("OOM while clearing gcNurseryEphemeronEdges.");
+  }
+}
+
+void Zone::traceWeakCCWEdges(JSTracer* trc) {
+  crossZoneStringWrappers().traceWeak(trc);
+  for (CompartmentsInZoneIter comp(this); !comp.done(); comp.next()) {
+    comp->traceCrossCompartmentObjectWrapperEdges(trc);
+  }
+}
+
+/* static */
+void Zone::fixupAllCrossCompartmentWrappersAfterMovingGC(JSTracer* trc) {
+  MOZ_ASSERT(trc->runtime()->gc.isHeapCompacting());
+
+  for (ZonesIter zone(trc->runtime(), WithAtoms); !zone.done(); zone.next()) {
+    // Trace the wrapper map to update keys (wrapped values) in other
+    // compartments that may have been moved.
+    zone->crossZoneStringWrappers().traceWeak(trc);
+
+    for (CompartmentsInZoneIter comp(zone); !comp.done(); comp.next()) {
+      comp->fixupCrossCompartmentObjectWrappersAfterMovingGC(trc);
+    }
+  }
+}
+
+void Zone::dropStringWrappersOnGC() {
+  MOZ_ASSERT(JS::RuntimeHeapIsCollecting());
+  crossZoneStringWrappers().clear();
+}
+
+#ifdef JSGC_HASH_TABLE_CHECKS
+
+void Zone::checkAllCrossCompartmentWrappersAfterMovingGC() {
+  checkStringWrappersAfterMovingGC();
+  for (CompartmentsInZoneIter comp(this); !comp.done(); comp.next()) {
+    comp->checkObjectWrappersAfterMovingGC();
+  }
+}
+
+void Zone::checkStringWrappersAfterMovingGC() {
+  for (StringWrapperMap::Enum e(crossZoneStringWrappers()); !e.empty();
+       e.popFront()) {
+    // Assert that the postbarriers have worked and that nothing is left in the
+    // wrapper map that points into the nursery, and that the hash table entries
+    // are discoverable.
+    auto key = e.front().key();
+    CheckGCThingAfterMovingGC(key.get());
+
+    auto ptr = crossZoneStringWrappers().lookup(key);
+    MOZ_RELEASE_ASSERT(ptr.found() && &*ptr == &e.front());
+  }
+}
+#endif
+
+void Zone::discardJitCode(JS::GCContext* gcx, const DiscardOptions& options) {
+  if (!isPreservingCode()) {
+    forceDiscardJitCode(gcx, options);
+  }
+}
+
+void Zone::forceDiscardJitCode(JS::GCContext* gcx,
+                               const DiscardOptions& options) {
+  if (!jitZone()) {
+    return;
+  }
+
+  if (options.discardJitScripts && options.discardBaselineCode) {
+    lastDiscardedCodeTime_ = mozilla::TimeStamp::Now();
+  }
+
+  if (options.discardBaselineCode || options.discardJitScripts) {
+#ifdef DEBUG
+    // Assert no JitScripts are marked as active.
+    for (auto iter = cellIter<BaseScript>(); !iter.done(); iter.next()) {
+      BaseScript* base = iter.unbarrieredGet();
+      if (jit::JitScript* jitScript = base->maybeJitScript()) {
+        MOZ_ASSERT(!jitScript->active());
+      }
+    }
+#endif
+
+    // Mark JitScripts on the stack as active.
+    jit::MarkActiveJitScripts(this);
+  }
+
+  // Invalidate all Ion code in this zone.
+  jit::InvalidateAll(gcx, this);
+
+  for (auto base = cellIterUnsafe<BaseScript>(); !base.done(); base.next()) {
+    jit::JitScript* jitScript = base->maybeJitScript();
+    if (!jitScript) {
+      continue;
+    }
+
+    JSScript* script = base->asJSScript();
+    jit::FinishInvalidation(gcx, script);
+
+    // Discard baseline script if it's not marked as active.
+    if (options.discardBaselineCode) {
+      if (jitScript->hasBaselineScript() && !jitScript->active()) {
+        jit::FinishDiscardBaselineScript(gcx, script);
+      }
+    }
+
+#ifdef JS_CACHEIR_SPEW
+    maybeUpdateWarmUpCount(script);
+#endif
+
+    // Warm-up counter for scripts are reset on GC. After discarding code we
+    // need to let it warm back up to get information such as which
+    // opcodes are setting array holes or accessing getter properties.
+    script->resetWarmUpCounterForGC();
+
+    // Try to release the script's JitScript. This should happen after
+    // releasing JIT code because we can't do this when the script still has
+    // JIT code.
+    if (options.discardJitScripts) {
+      script->maybeReleaseJitScript(gcx);
+      jitScript = script->maybeJitScript();
+      if (!jitScript) {
+        // Try to discard the ScriptCounts too.
+        if (!script->realm()->collectCoverageForDebug() &&
+            !gcx->runtime()->profilingScripts) {
+          script->destroyScriptCounts();
+        }
+        continue;
+      }
+    }
+
+    // If we did not release the JitScript, we need to purge optimized IC
+    // stubs because the optimizedStubSpace will be purged below.
+    if (options.discardBaselineCode) {
+      jitScript->purgeOptimizedStubs(script);
+    }
+
+    if (options.resetNurseryAllocSites || options.resetPretenuredAllocSites) {
+      jitScript->resetAllocSites(options.resetNurseryAllocSites,
+                                 options.resetPretenuredAllocSites);
+    }
+
+    // Finally, reset the active flag.
+    jitScript->resetActive();
+  }
+
+  // Also clear references to jit code from RegExpShared cells at this point.
+  // This avoid holding onto ExecutablePools.
+  for (auto regExp = cellIterUnsafe<RegExpShared>(); !regExp.done();
+       regExp.next()) {
+    regExp->discardJitCode();
+  }
+
+  /*
+   * When scripts contains pointers to nursery things, the store buffer
+   * can contain entries that point into the optimized stub space. Since
+   * this method can be called outside the context of a GC, this situation
+   * could result in us trying to mark invalid store buffer entries.
+   *
+   * Defer freeing any allocated blocks until after the next minor GC.
+   */
+  if (options.discardBaselineCode) {
+    jitZone()->optimizedStubSpace()->freeAllAfterMinorGC(this);
+    jitZone()->purgeIonCacheIRStubInfo();
+  }
+
+  // Generate a profile marker
+  if (gcx->runtime()->geckoProfiler().enabled()) {
+    char discardingJitScript = options.discardJitScripts ? 'Y' : 'N';
+    char discardingBaseline = options.discardBaselineCode ? 'Y' : 'N';
+    char discardingIon = 'Y';
+
+    char discardingRegExp = 'Y';
+    char discardingNurserySites = options.resetNurseryAllocSites ? 'Y' : 'N';
+    char discardingPretenuredSites =
+        options.resetPretenuredAllocSites ? 'Y' : 'N';
+
+    char buf[100];
+    SprintfLiteral(buf,
+                   "JitScript:%c Baseline:%c Ion:%c "
+                   "RegExp:%c NurserySites:%c PretenuredSites:%c",
+                   discardingJitScript, discardingBaseline, discardingIon,
+                   discardingRegExp, discardingNurserySites,
+                   discardingPretenuredSites);
+    gcx->runtime()->geckoProfiler().markEvent("DiscardJit", buf);
+  }
+}
+
+void JS::Zone::resetAllocSitesAndInvalidate(bool resetNurserySites,
+                                            bool resetPretenuredSites) {
+  MOZ_ASSERT(resetNurserySites || resetPretenuredSites);
+
+  if (!jitZone()) {
+    return;
+  }
+
+  JSContext* cx = runtime_->mainContextFromOwnThread();
+  for (auto base = cellIterUnsafe<BaseScript>(); !base.done(); base.next()) {
+    jit::JitScript* jitScript = base->maybeJitScript();
+    if (!jitScript) {
+      continue;
+    }
+
+    if (!jitScript->resetAllocSites(resetNurserySites, resetPretenuredSites)) {
+      continue;
+    }
+
+    JSScript* script = base->asJSScript();
+    CancelOffThreadIonCompile(script);
+
+    if (!script->hasIonScript()) {
+      continue;
+    }
+
+    jit::Invalidate(cx, script,
+                    /* resetUses = */ true,
+                    /* cancelOffThread = */ true);
+  }
+}
+
+void JS::Zone::beforeClearDelegateInternal(JSObject* wrapper,
+                                           JSObject* delegate) {
+  MOZ_ASSERT(js::gc::detail::GetDelegate(wrapper) == delegate);
+  MOZ_ASSERT(needsIncrementalBarrier());
+  MOZ_ASSERT(!RuntimeFromMainThreadIsHeapMajorCollecting(this));
+  runtimeFromMainThread()->gc.marker().severWeakDelegate(wrapper, delegate);
+}
+
+void JS::Zone::afterAddDelegateInternal(JSObject* wrapper) {
+  MOZ_ASSERT(!RuntimeFromMainThreadIsHeapMajorCollecting(this));
+  JSObject* delegate = js::gc::detail::GetDelegate(wrapper);
+  if (delegate) {
+    runtimeFromMainThread()->gc.marker().restoreWeakDelegate(wrapper, delegate);
+  }
+}
+
+#ifdef JSGC_HASH_TABLE_CHECKS
+void JS::Zone::checkUniqueIdTableAfterMovingGC() {
+  for (auto r = uniqueIds().all(); !r.empty(); r.popFront()) {
+    js::gc::CheckGCThingAfterMovingGC(r.front().key());
+  }
+}
+#endif
+
+js::jit::JitZone* Zone::createJitZone(JSContext* cx) {
+  MOZ_ASSERT(!jitZone_);
+  MOZ_ASSERT(cx->runtime()->hasJitRuntime());
+
+  UniquePtr<jit::JitZone> jitZone(cx->new_<js::jit::JitZone>());
+  if (!jitZone) {
+    return nullptr;
+  }
+
+  jitZone_ = jitZone.release();
+  return jitZone_;
+}
+
+bool Zone::hasMarkedRealms() {
+  for (RealmsInZoneIter realm(this); !realm.done(); realm.next()) {
+    if (realm->marked()) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void Zone::notifyObservingDebuggers() {
+  AutoAssertNoGC nogc;
+  MOZ_ASSERT(JS::RuntimeHeapIsCollecting(),
+             "This method should be called during GC.");
+
+  JSRuntime* rt = runtimeFromMainThread();
+
+  for (RealmsInZoneIter realms(this); !realms.done(); realms.next()) {
+    GlobalObject* global = realms->unsafeUnbarrieredMaybeGlobal();
+    if (!global) {
+      continue;
+    }
+
+    DebugAPI::notifyParticipatesInGC(global, rt->gc.majorGCCount());
+  }
+}
+
+bool Zone::isOnList() const { return listNext_ != NotOnList; }
+
+Zone* Zone::nextZone() const {
+  MOZ_ASSERT(isOnList());
+  return listNext_;
+}
+
+void Zone::fixupAfterMovingGC() {
+  ZoneAllocator::fixupAfterMovingGC();
+  shapeZone().fixupPropMapShapeTableAfterMovingGC();
+}
+
+void Zone::purgeAtomCache() {
+  atomCache().clearAndCompact();
+
+  // Also purge the dtoa caches so that subsequent lookups populate atom
+  // cache too.
+  for (RealmsInZoneIter r(this); !r.done(); r.next()) {
+    r->dtoaCache.purge();
+  }
+}
+
+void Zone::addSizeOfIncludingThis(
+    mozilla::MallocSizeOf mallocSizeOf, JS::CodeSizes* code, size_t* regexpZone,
+    size_t* jitZone, size_t* baselineStubsOptimized, size_t* uniqueIdMap,
+    size_t* initialPropMapTable, size_t* shapeTables, size_t* atomsMarkBitmaps,
+    size_t* compartmentObjects, size_t* crossCompartmentWrappersTables,
+    size_t* compartmentsPrivateData, size_t* scriptCountsMapArg) {
+  *regexpZone += regExps().sizeOfIncludingThis(mallocSizeOf);
+  if (jitZone_) {
+    jitZone_->addSizeOfIncludingThis(mallocSizeOf, code, jitZone,
+                                     baselineStubsOptimized);
+  }
+  *uniqueIdMap += uniqueIds().shallowSizeOfExcludingThis(mallocSizeOf);
+  shapeZone().addSizeOfExcludingThis(mallocSizeOf, initialPropMapTable,
+                                     shapeTables);
+  *atomsMarkBitmaps += markedAtoms().sizeOfExcludingThis(mallocSizeOf);
+  *crossCompartmentWrappersTables +=
+      crossZoneStringWrappers().sizeOfExcludingThis(mallocSizeOf);
+
+  for (CompartmentsInZoneIter comp(this); !comp.done(); comp.next()) {
+    comp->addSizeOfIncludingThis(mallocSizeOf, compartmentObjects,
+                                 crossCompartmentWrappersTables,
+                                 compartmentsPrivateData);
+  }
+
+  if (scriptCountsMap) {
+    *scriptCountsMapArg +=
+        scriptCountsMap->shallowSizeOfIncludingThis(mallocSizeOf);
+    for (auto r = scriptCountsMap->all(); !r.empty(); r.popFront()) {
+      *scriptCountsMapArg +=
+          r.front().value()->sizeOfIncludingThis(mallocSizeOf);
+    }
+  }
+}
+
+void* ZoneAllocator::onOutOfMemory(js::AllocFunction allocFunc,
+                                   arena_id_t arena, size_t nbytes,
+                                   void* reallocPtr) {
+  if (!js::CurrentThreadCanAccessRuntime(runtime_)) {
+    return nullptr;
+  }
+  // The analysis sees that JSRuntime::onOutOfMemory could report an error,
+  // which with a JSErrorInterceptor could GC. But we're passing a null cx (to
+  // a default parameter) so the error will not be reported.
+  JS::AutoSuppressGCAnalysis suppress;
+  return runtimeFromMainThread()->onOutOfMemory(allocFunc, arena, nbytes,
+                                                reallocPtr);
+}
+
+void ZoneAllocator::reportAllocationOverflow() const {
+  js::ReportAllocationOverflow(static_cast<JSContext*>(nullptr));
+}
+
+ZoneList::ZoneList() : head(nullptr), tail(nullptr) {}
+
+ZoneList::ZoneList(Zone* zone) : head(zone), tail(zone) {
+  MOZ_RELEASE_ASSERT(!zone->isOnList());
+  zone->listNext_ = nullptr;
+}
+
+ZoneList::~ZoneList() { MOZ_ASSERT(isEmpty()); }
+
+void ZoneList::check() const {
+#ifdef DEBUG
+  MOZ_ASSERT((head == nullptr) == (tail == nullptr));
+  if (!head) {
+    return;
+  }
+
+  Zone* zone = head;
+  for (;;) {
+    MOZ_ASSERT(zone && zone->isOnList());
+    if (zone == tail) break;
+    zone = zone->listNext_;
+  }
+  MOZ_ASSERT(!zone->listNext_);
+#endif
+}
+
+bool ZoneList::isEmpty() const { return head == nullptr; }
+
+Zone* ZoneList::front() const {
+  MOZ_ASSERT(!isEmpty());
+  MOZ_ASSERT(head->isOnList());
+  return head;
+}
+
+void ZoneList::prepend(Zone* zone) { prependList(ZoneList(zone)); }
+
+void ZoneList::append(Zone* zone) { appendList(ZoneList(zone)); }
+
+void ZoneList::prependList(ZoneList&& other) {
+  check();
+  other.check();
+
+  if (other.isEmpty()) {
+    return;
+  }
+
+  MOZ_ASSERT(tail != other.tail);
+
+  if (!isEmpty()) {
+    other.tail->listNext_ = head;
+  } else {
+    tail = other.tail;
+  }
+  head = other.head;
+
+  other.head = nullptr;
+  other.tail = nullptr;
+}
+
+void ZoneList::appendList(ZoneList&& other) {
+  check();
+  other.check();
+
+  if (other.isEmpty()) {
+    return;
+  }
+
+  MOZ_ASSERT(tail != other.tail);
+
+  if (!isEmpty()) {
+    tail->listNext_ = other.head;
+  } else {
+    head = other.head;
+  }
+  tail = other.tail;
+
+  other.head = nullptr;
+  other.tail = nullptr;
+}
+
+Zone* ZoneList::removeFront() {
+  MOZ_ASSERT(!isEmpty());
+  check();
+
+  Zone* front = head;
+  head = head->listNext_;
+  if (!head) {
+    tail = nullptr;
+  }
+
+  front->listNext_ = Zone::NotOnList;
+
+  return front;
+}
+
+void ZoneList::clear() {
+  while (!isEmpty()) {
+    removeFront();
+  }
+}
+
+JS_PUBLIC_API void JS::shadow::RegisterWeakCache(
+    JS::Zone* zone, detail::WeakCacheBase* cachep) {
+  zone->registerWeakCache(cachep);
+}
+
+void Zone::traceRootsInMajorGC(JSTracer* trc) {
+  if (trc->isMarkingTracer() && !isGCMarking()) {
+    return;
+  }
+
+  // Trace zone script-table roots. See comment below for justification re:
+  // calling this only during major (non-nursery) collections.
+  traceScriptTableRoots(trc);
+
+  if (FinalizationObservers* observers = finalizationObservers()) {
+    observers->traceRoots(trc);
+  }
+}
+
+void Zone::traceScriptTableRoots(JSTracer* trc) {
+  static_assert(std::is_convertible_v<BaseScript*, gc::TenuredCell*>,
+                "BaseScript must not be nursery-allocated for script-table "
+                "tracing to work");
+
+  // Performance optimization: the script-table keys are JSScripts, which
+  // cannot be in the nursery, so we can skip this tracing if we are only in a
+  // minor collection. We static-assert this fact above.
+  MOZ_ASSERT(!JS::RuntimeHeapIsMinorCollecting());
+
+  // N.B.: the script-table keys are weak *except* in an exceptional case: when
+  // then --dump-bytecode command line option or the PCCount JSFriend API is
+  // used, then the scripts for all counts must remain alive. We only trace
+  // when the `trc->runtime()->profilingScripts` flag is set. This flag is
+  // cleared in JSRuntime::destroyRuntime() during shutdown to ensure that
+  // scripts are collected before the runtime goes away completely.
+  if (scriptCountsMap && trc->runtime()->profilingScripts) {
+    for (ScriptCountsMap::Range r = scriptCountsMap->all(); !r.empty();
+         r.popFront()) {
+      BaseScript* script = r.front().key();
+      MOZ_ASSERT(script->hasScriptCounts());
+      TraceRoot(trc, &script, "profilingScripts");
+    }
+  }
+
+  // Trace the debugger's DebugScript weak map.
+  if (debugScriptMap) {
+    DebugAPI::traceDebugScriptMap(trc, debugScriptMap);
+  }
+}
+
+void Zone::fixupScriptMapsAfterMovingGC(JSTracer* trc) {
+  // Map entries are removed by BaseScript::finalize, but we need to update the
+  // script pointers here in case they are moved by the GC.
+
+  if (scriptCountsMap) {
+    scriptCountsMap->traceWeak(trc);
+  }
+
+  if (scriptLCovMap) {
+    scriptLCovMap->traceWeak(trc);
+  }
+
+#ifdef MOZ_VTUNE
+  if (scriptVTuneIdMap) {
+    scriptVTuneIdMap->traceWeak(trc);
+  }
+#endif
+
+#ifdef JS_CACHEIR_SPEW
+  if (scriptFinalWarmUpCountMap) {
+    scriptFinalWarmUpCountMap->traceWeak(trc);
+  }
+#endif
+}
+
+#ifdef JSGC_HASH_TABLE_CHECKS
+void Zone::checkScriptMapsAfterMovingGC() {
+  if (scriptCountsMap) {
+    for (auto r = scriptCountsMap->all(); !r.empty(); r.popFront()) {
+      BaseScript* script = r.front().key();
+      MOZ_ASSERT(script->zone() == this);
+      CheckGCThingAfterMovingGC(script);
+      auto ptr = scriptCountsMap->lookup(script);
+      MOZ_RELEASE_ASSERT(ptr.found() && &*ptr == &r.front());
+    }
+  }
+
+  if (scriptLCovMap) {
+    for (auto r = scriptLCovMap->all(); !r.empty(); r.popFront()) {
+      BaseScript* script = r.front().key();
+      MOZ_ASSERT(script->zone() == this);
+      CheckGCThingAfterMovingGC(script);
+      auto ptr = scriptLCovMap->lookup(script);
+      MOZ_RELEASE_ASSERT(ptr.found() && &*ptr == &r.front());
+    }
+  }
+
+#  ifdef MOZ_VTUNE
+  if (scriptVTuneIdMap) {
+    for (auto r = scriptVTuneIdMap->all(); !r.empty(); r.popFront()) {
+      BaseScript* script = r.front().key();
+      MOZ_ASSERT(script->zone() == this);
+      CheckGCThingAfterMovingGC(script);
+      auto ptr = scriptVTuneIdMap->lookup(script);
+      MOZ_RELEASE_ASSERT(ptr.found() && &*ptr == &r.front());
+    }
+  }
+#  endif  // MOZ_VTUNE
+
+#  ifdef JS_CACHEIR_SPEW
+  if (scriptFinalWarmUpCountMap) {
+    for (auto r = scriptFinalWarmUpCountMap->all(); !r.empty(); r.popFront()) {
+      BaseScript* script = r.front().key();
+      MOZ_ASSERT(script->zone() == this);
+      CheckGCThingAfterMovingGC(script);
+      auto ptr = scriptFinalWarmUpCountMap->lookup(script);
+      MOZ_RELEASE_ASSERT(ptr.found() && &*ptr == &r.front());
+    }
+  }
+#  endif  // JS_CACHEIR_SPEW
+}
+#endif
+
+void Zone::clearScriptCounts(Realm* realm) {
+  if (!scriptCountsMap) {
+    return;
+  }
+
+  // Clear all hasScriptCounts_ flags of BaseScript, in order to release all
+  // ScriptCounts entries of the given realm.
+  for (auto i = scriptCountsMap->modIter(); !i.done(); i.next()) {
+    BaseScript* script = i.get().key();
+    if (script->realm() != realm) {
+      continue;
+    }
+    // We can't destroy the ScriptCounts yet if the script has Baseline code,
+    // because Baseline code bakes in pointers to the counters. The ScriptCounts
+    // will be destroyed in Zone::discardJitCode when discarding the JitScript.
+    if (script->hasBaselineScript()) {
+      continue;
+    }
+    script->clearHasScriptCounts();
+    i.remove();
+  }
+}
+
+void Zone::clearScriptLCov(Realm* realm) {
+  if (!scriptLCovMap) {
+    return;
+  }
+
+  for (auto i = scriptLCovMap->modIter(); !i.done(); i.next()) {
+    BaseScript* script = i.get().key();
+    if (script->realm() == realm) {
+      i.remove();
+    }
+  }
+}
+
+void Zone::clearRootsForShutdownGC() {
+  // Finalization callbacks are not called if we're shutting down.
+  if (finalizationObservers()) {
+    finalizationObservers()->clearRecords();
+  }
+
+  clearKeptObjects();
+}
+
+void Zone::finishRoots() {
+  for (RealmsInZoneIter r(this); !r.done(); r.next()) {
+    r->finishRoots();
+  }
+}
+
+void Zone::traceKeptObjects(JSTracer* trc) { keptObjects.ref().trace(trc); }
+
+bool Zone::keepDuringJob(HandleObject target) {
+  return keptObjects.ref().put(target);
+}
+
+void Zone::clearKeptObjects() { keptObjects.ref().clear(); }
+
+bool Zone::ensureFinalizationObservers() {
+  if (finalizationObservers_.ref()) {
+    return true;
+  }
+
+  finalizationObservers_ = js::MakeUnique<FinalizationObservers>(this);
+  return bool(finalizationObservers_.ref());
+}