Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 760 insertions, 0 deletions

diff --git a/js/src/vm/Realm.cpp b/js/src/vm/Realm.cpp
new file mode 100644
index 0000000000..d2ad39f3db
--- /dev/null
+++ b/js/src/vm/Realm.cpp
@@ -0,0 +1,760 @@
+/* -*- 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 "js/shadow/Realm.h"  // JS::shadow::Realm
+#include "vm/Realm-inl.h"
+
+#include "mozilla/MemoryReporting.h"
+
+#include <stddef.h>
+
+#include "jsfriendapi.h"
+
+#include "builtin/WrappedFunctionObject.h"
+#include "debugger/DebugAPI.h"
+#include "debugger/Debugger.h"
+#include "gc/GC.h"
+#include "jit/JitRuntime.h"
+#include "js/CallAndConstruct.h"      // JS::IsCallable
+#include "js/friend/ErrorMessages.h"  // js::GetErrorMessage, JSMSG_*
+#include "js/GCVariant.h"
+#include "js/Proxy.h"
+#include "js/RootingAPI.h"
+#include "js/Wrapper.h"
+#include "vm/Compartment.h"
+#include "vm/DateTime.h"
+#include "vm/Iteration.h"
+#include "vm/JSContext.h"
+#include "vm/PIC.h"
+
+#include "gc/Marking-inl.h"
+#include "vm/JSObject-inl.h"
+
+using namespace js;
+
+Realm::DebuggerVectorEntry::DebuggerVectorEntry(js::Debugger* dbg_,
+                                                JSObject* link)
+    : dbg(dbg_), debuggerLink(link) {}
+
+ObjectRealm::ObjectRealm(JS::Zone* zone)
+    : innerViews(zone, zone), iteratorCache(zone) {}
+
+Realm::Realm(Compartment* comp, const JS::RealmOptions& options)
+    : JS::shadow::Realm(comp),
+      zone_(comp->zone()),
+      runtime_(comp->runtimeFromMainThread()),
+      creationOptions_(options.creationOptions()),
+      behaviors_(options.behaviors()),
+      objects_(zone_),
+      randomKeyGenerator_(runtime_->forkRandomKeyGenerator()),
+      debuggers_(zone_),
+      allocatedDuringIncrementalGC_(zone_->isGCMarkingOrSweeping() ||
+                                    zone_->isGCFinished()),
+      wasm(runtime_) {
+  runtime_->numRealms++;
+}
+
+Realm::~Realm() {
+  MOZ_ASSERT(!hasBeenEnteredIgnoringJit());
+  MOZ_ASSERT(!isDebuggee());
+
+  // Write the code coverage information in a file.
+  if (lcovRealm_) {
+    runtime_->lcovOutput().writeLCovResult(*lcovRealm_);
+  }
+
+  if (allocationMetadataBuilder_) {
+    forgetAllocationMetadataBuilder();
+  }
+
+  MOZ_ASSERT(runtime_->numRealms > 0);
+  runtime_->numRealms--;
+}
+
+void Realm::init(JSContext* cx, JSPrincipals* principals) {
+  /*
+   * As a hack, we clear our timezone cache every time we create a new realm.
+   * This ensures that the cache is always relatively fresh, but shouldn't
+   * interfere with benchmarks that create tons of date objects (unless they
+   * also create tons of iframes, which seems unlikely).
+   */
+  js::ResetTimeZoneInternal(ResetTimeZoneMode::DontResetIfOffsetUnchanged);
+
+  if (principals) {
+    // Any realm with the trusted principals -- and there can be
+    // multiple -- is a system realm.
+    isSystem_ = (principals == cx->runtime()->trustedPrincipals());
+    JS_HoldPrincipals(principals);
+    principals_ = principals;
+  }
+}
+
+bool JSRuntime::createJitRuntime(JSContext* cx) {
+  using namespace js::jit;
+
+  MOZ_ASSERT(!jitRuntime_);
+
+  if (!CanLikelyAllocateMoreExecutableMemory()) {
+    // Try to release memory first instead of potentially reporting OOM below.
+    if (OnLargeAllocationFailure) {
+      OnLargeAllocationFailure();
+    }
+  }
+
+  jit::JitRuntime* jrt = cx->new_<jit::JitRuntime>();
+  if (!jrt) {
+    return false;
+  }
+
+  // Unfortunately, initialization depends on jitRuntime_ being non-null, so
+  // we can't just wait to assign jitRuntime_.
+  jitRuntime_ = jrt;
+
+  if (!jitRuntime_->initialize(cx)) {
+    js_delete(jitRuntime_.ref());
+    jitRuntime_ = nullptr;
+    return false;
+  }
+
+  return true;
+}
+
+#ifdef JSGC_HASH_TABLE_CHECKS
+
+void js::DtoaCache::checkCacheAfterMovingGC() {
+  MOZ_ASSERT(!str || !IsForwarded(str));
+}
+
+#endif  // JSGC_HASH_TABLE_CHECKS
+
+NonSyntacticLexicalEnvironmentObject*
+ObjectRealm::getOrCreateNonSyntacticLexicalEnvironment(JSContext* cx,
+                                                       HandleObject enclosing,
+                                                       HandleObject key,
+                                                       HandleObject thisv) {
+  MOZ_ASSERT(&ObjectRealm::get(enclosing) == this);
+
+  if (!nonSyntacticLexicalEnvironments_) {
+    auto map = cx->make_unique<ObjectWeakMap>(cx);
+    if (!map) {
+      return nullptr;
+    }
+
+    nonSyntacticLexicalEnvironments_ = std::move(map);
+  }
+
+  RootedObject lexicalEnv(cx, nonSyntacticLexicalEnvironments_->lookup(key));
+
+  if (!lexicalEnv) {
+    MOZ_ASSERT(key->is<NonSyntacticVariablesObject>() ||
+               !key->is<EnvironmentObject>());
+    lexicalEnv =
+        NonSyntacticLexicalEnvironmentObject::create(cx, enclosing, thisv);
+    if (!lexicalEnv) {
+      return nullptr;
+    }
+    if (!nonSyntacticLexicalEnvironments_->add(cx, key, lexicalEnv)) {
+      return nullptr;
+    }
+  }
+
+  return &lexicalEnv->as<NonSyntacticLexicalEnvironmentObject>();
+}
+
+NonSyntacticLexicalEnvironmentObject*
+ObjectRealm::getOrCreateNonSyntacticLexicalEnvironment(JSContext* cx,
+                                                       HandleObject enclosing) {
+  // If a wrapped WithEnvironmentObject was passed in, unwrap it, as we may
+  // be creating different WithEnvironmentObject wrappers each time.
+  RootedObject key(cx, enclosing);
+  if (enclosing->is<WithEnvironmentObject>()) {
+    MOZ_ASSERT(!enclosing->as<WithEnvironmentObject>().isSyntactic());
+    key = &enclosing->as<WithEnvironmentObject>().object();
+  }
+
+  // NOTE: The default global |this| value is set to key for compatibility
+  // with existing users of the lexical environment cache.
+  //  - When used by shared-global JSM loader, |this| must be the
+  //    NonSyntacticVariablesObject passed as enclosing.
+  //  - When used by SubscriptLoader, |this| must be the target object of
+  //    the WithEnvironmentObject wrapper.
+  //  - When used by XBL/DOM Events, we execute directly as a function and
+  //    do not access the |this| value.
+  // See js::GetFunctionThis / js::GetNonSyntacticGlobalThis
+  return getOrCreateNonSyntacticLexicalEnvironment(cx, enclosing, key,
+                                                   /*thisv = */ key);
+}
+
+NonSyntacticLexicalEnvironmentObject*
+ObjectRealm::getNonSyntacticLexicalEnvironment(JSObject* key) const {
+  MOZ_ASSERT(&ObjectRealm::get(key) == this);
+
+  if (!nonSyntacticLexicalEnvironments_) {
+    return nullptr;
+  }
+  // If a wrapped WithEnvironmentObject was passed in, unwrap it as in
+  // getOrCreateNonSyntacticLexicalEnvironment.
+  if (key->is<WithEnvironmentObject>()) {
+    MOZ_ASSERT(!key->as<WithEnvironmentObject>().isSyntactic());
+    key = &key->as<WithEnvironmentObject>().object();
+  }
+  JSObject* lexicalEnv = nonSyntacticLexicalEnvironments_->lookup(key);
+  if (!lexicalEnv) {
+    return nullptr;
+  }
+  return &lexicalEnv->as<NonSyntacticLexicalEnvironmentObject>();
+}
+
+void Realm::traceGlobalData(JSTracer* trc) {
+  // Trace things reachable from the realm's global. Note that these edges
+  // must be swept too in case the realm is live but the global is not.
+
+  savedStacks_.trace(trc);
+
+  DebugAPI::traceFromRealm(trc, this);
+}
+
+void ObjectRealm::trace(JSTracer* trc) {
+  if (objectMetadataTable) {
+    objectMetadataTable->trace(trc);
+  }
+
+  if (nonSyntacticLexicalEnvironments_) {
+    nonSyntacticLexicalEnvironments_->trace(trc);
+  }
+}
+
+void Realm::traceRoots(JSTracer* trc,
+                       js::gc::GCRuntime::TraceOrMarkRuntime traceOrMark) {
+  // It's not possible to trigger a GC between allocating the pending object and
+  // setting its meta data in ~AutoSetNewObjectMetadata.
+  MOZ_RELEASE_ASSERT(!objectPendingMetadata_);
+
+  if (!JS::RuntimeHeapIsMinorCollecting()) {
+    // The global is never nursery allocated, so we don't need to
+    // trace it when doing a minor collection.
+    //
+    // If a realm is on-stack, we mark its global so that
+    // JSContext::global() remains valid.
+    if (shouldTraceGlobal() && global_) {
+      TraceRoot(trc, global_.unbarrieredAddress(), "on-stack realm global");
+    }
+  }
+
+  // Nothing below here needs to be treated as a root if we aren't marking
+  // this zone for a collection.
+  if (traceOrMark == js::gc::GCRuntime::MarkRuntime &&
+      !zone()->isCollectingFromAnyThread()) {
+    return;
+  }
+
+  /* Mark debug scopes, if present */
+  if (debugEnvs_) {
+    debugEnvs_->trace(trc);
+  }
+
+  objects_.trace(trc);
+}
+
+void ObjectRealm::finishRoots() {
+  if (objectMetadataTable) {
+    objectMetadataTable->clear();
+  }
+
+  if (nonSyntacticLexicalEnvironments_) {
+    nonSyntacticLexicalEnvironments_->clear();
+  }
+}
+
+void Realm::finishRoots() {
+  if (debugEnvs_) {
+    debugEnvs_->finish();
+  }
+
+  objects_.finishRoots();
+}
+
+void ObjectRealm::sweepAfterMinorGC(JSTracer* trc) {
+  InnerViewTable& table = innerViews.get();
+  if (table.needsSweepAfterMinorGC()) {
+    table.sweepAfterMinorGC(trc);
+  }
+}
+
+void Realm::sweepAfterMinorGC(JSTracer* trc) {
+  globalWriteBarriered = 0;
+  dtoaCache.purge();
+  objects_.sweepAfterMinorGC(trc);
+}
+
+void Realm::traceWeakSavedStacks(JSTracer* trc) { savedStacks_.traceWeak(trc); }
+
+void Realm::traceWeakGlobalEdge(JSTracer* trc) {
+  // If the global is dead, free its GlobalObjectData.
+  auto result = TraceWeakEdge(trc, &global_, "Realm::global_");
+  if (result.isDead()) {
+    result.initialTarget()->releaseData(runtime_->gcContext());
+  }
+}
+
+void Realm::traceWeakDebugEnvironmentEdges(JSTracer* trc) {
+  if (debugEnvs_) {
+    debugEnvs_->traceWeak(trc);
+  }
+}
+
+void Realm::fixupAfterMovingGC(JSTracer* trc) {
+  purge();
+  traceWeakGlobalEdge(trc);
+}
+
+void Realm::purge() {
+  dtoaCache.purge();
+  newProxyCache.purge();
+  newPlainObjectWithPropsCache.purge();
+  plainObjectAssignCache.purge();
+  objects_.iteratorCache.clearAndCompact();
+  arraySpeciesLookup.purge();
+  promiseLookup.purge();
+
+  if (zone()->isGCPreparing()) {
+    purgeForOfPicChain();
+  }
+}
+
+void Realm::purgeForOfPicChain() {
+  if (GlobalObject* global = global_.unbarrieredGet()) {
+    if (NativeObject* object = global->getForOfPICObject()) {
+      ForOfPIC::Chain* chain = ForOfPIC::fromJSObject(object);
+      chain->freeAllStubs(runtime_->gcContext());
+    }
+  }
+}
+
+// Check to see if this individual realm is recording allocations. Debuggers or
+// runtimes can try and record allocations, so this method can check to see if
+// any initialization is needed.
+bool Realm::isRecordingAllocations() { return !!allocationMetadataBuilder_; }
+
+void Realm::setAllocationMetadataBuilder(
+    const js::AllocationMetadataBuilder* builder) {
+  // Clear any jitcode in the runtime, which behaves differently depending on
+  // whether there is a creation callback.
+  if (bool(allocationMetadataBuilder_) != bool(builder)) {
+    ReleaseAllJITCode(runtime_->gcContext());
+    if (builder) {
+      zone()->incNumRealmsWithAllocMetadataBuilder();
+    } else {
+      zone()->decNumRealmsWithAllocMetadataBuilder();
+    }
+  }
+
+  allocationMetadataBuilder_ = builder;
+}
+
+void Realm::forgetAllocationMetadataBuilder() {
+  if (!allocationMetadataBuilder_) {
+    return;
+  }
+
+  // Unlike setAllocationMetadataBuilder, we don't have to discard all JIT
+  // code here (code is still valid, just a bit slower because it doesn't do
+  // inline GC allocations when a metadata builder is present), but we do want
+  // to cancel off-thread Ion compilations to avoid races when Ion accesses
+  // numRealmsWithAllocMetadataBuilder_ off-thread.
+  CancelOffThreadIonCompile(zone());
+
+  zone()->decNumRealmsWithAllocMetadataBuilder();
+
+  allocationMetadataBuilder_ = nullptr;
+}
+
+void Realm::setNewObjectMetadata(JSContext* cx, HandleObject obj) {
+  MOZ_ASSERT(obj->maybeCCWRealm() == this);
+  cx->check(compartment(), obj);
+
+  AutoEnterOOMUnsafeRegion oomUnsafe;
+  if (JSObject* metadata =
+          allocationMetadataBuilder_->build(cx, obj, oomUnsafe)) {
+    MOZ_ASSERT(metadata->maybeCCWRealm() == obj->maybeCCWRealm());
+    cx->check(metadata);
+
+    if (!objects_.objectMetadataTable) {
+      auto table = cx->make_unique<ObjectWeakMap>(cx);
+      if (!table) {
+        oomUnsafe.crash("setNewObjectMetadata");
+      }
+
+      objects_.objectMetadataTable = std::move(table);
+    }
+
+    if (!objects_.objectMetadataTable->add(cx, obj, metadata)) {
+      oomUnsafe.crash("setNewObjectMetadata");
+    }
+  }
+}
+
+void Realm::updateDebuggerObservesFlag(unsigned flag) {
+  MOZ_ASSERT(isDebuggee());
+  MOZ_ASSERT(flag == DebuggerObservesAllExecution ||
+             flag == DebuggerObservesCoverage ||
+             flag == DebuggerObservesAsmJS || flag == DebuggerObservesWasm ||
+             flag == DebuggerObservesNativeCall);
+
+  GlobalObject* global =
+      zone()->runtimeFromMainThread()->gc.isForegroundSweeping()
+          ? unsafeUnbarrieredMaybeGlobal()
+          : maybeGlobal();
+  bool observes = false;
+  if (flag == DebuggerObservesAllExecution) {
+    observes = DebugAPI::debuggerObservesAllExecution(global);
+  } else if (flag == DebuggerObservesCoverage) {
+    observes = DebugAPI::debuggerObservesCoverage(global);
+  } else if (flag == DebuggerObservesAsmJS) {
+    observes = DebugAPI::debuggerObservesAsmJS(global);
+  } else if (flag == DebuggerObservesWasm) {
+    observes = DebugAPI::debuggerObservesWasm(global);
+  } else if (flag == DebuggerObservesNativeCall) {
+    observes = DebugAPI::debuggerObservesNativeCall(global);
+  }
+
+  if (observes) {
+    debugModeBits_ |= flag;
+  } else {
+    debugModeBits_ &= ~flag;
+  }
+}
+
+void Realm::setIsDebuggee() {
+  if (!isDebuggee()) {
+    debugModeBits_ |= IsDebuggee;
+    runtimeFromMainThread()->incrementNumDebuggeeRealms();
+  }
+}
+
+void Realm::unsetIsDebuggee() {
+  if (isDebuggee()) {
+    if (debuggerObservesCoverage()) {
+      runtime_->decrementNumDebuggeeRealmsObservingCoverage();
+    }
+    debugModeBits_ = 0;
+    DebugEnvironments::onRealmUnsetIsDebuggee(this);
+    runtimeFromMainThread()->decrementNumDebuggeeRealms();
+  }
+}
+
+void Realm::updateDebuggerObservesCoverage() {
+  bool previousState = debuggerObservesCoverage();
+  updateDebuggerObservesFlag(DebuggerObservesCoverage);
+  if (previousState == debuggerObservesCoverage()) {
+    return;
+  }
+
+  if (debuggerObservesCoverage()) {
+    // Interrupt any running interpreter frame. The scriptCounts are
+    // allocated on demand when a script resumes its execution.
+    JSContext* cx = TlsContext.get();
+    for (ActivationIterator iter(cx); !iter.done(); ++iter) {
+      if (iter->isInterpreter()) {
+        iter->asInterpreter()->enableInterruptsUnconditionally();
+      }
+    }
+    runtime_->incrementNumDebuggeeRealmsObservingCoverage();
+    return;
+  }
+
+  runtime_->decrementNumDebuggeeRealmsObservingCoverage();
+
+  // If code coverage is enabled by any other means, keep it.
+  if (collectCoverageForDebug()) {
+    return;
+  }
+
+  clearScriptCounts();
+  clearScriptLCov();
+}
+
+coverage::LCovRealm* Realm::lcovRealm() {
+  if (!lcovRealm_) {
+    lcovRealm_ = js::MakeUnique<coverage::LCovRealm>(this);
+  }
+  return lcovRealm_.get();
+}
+
+bool Realm::collectCoverageForDebug() const {
+  return debuggerObservesCoverage() || coverage::IsLCovEnabled();
+}
+
+void Realm::clearScriptCounts() { zone()->clearScriptCounts(this); }
+
+void Realm::clearScriptLCov() { zone()->clearScriptLCov(this); }
+
+const char* Realm::getLocale() const {
+  if (RefPtr<LocaleString> locale = creationOptions_.locale()) {
+    return locale->chars();
+  }
+
+  return runtime_->getDefaultLocale();
+}
+
+void ObjectRealm::addSizeOfExcludingThis(
+    mozilla::MallocSizeOf mallocSizeOf, size_t* innerViewsArg,
+    size_t* objectMetadataTablesArg,
+    size_t* nonSyntacticLexicalEnvironmentsArg) {
+  *innerViewsArg += innerViews.sizeOfExcludingThis(mallocSizeOf);
+
+  if (objectMetadataTable) {
+    *objectMetadataTablesArg +=
+        objectMetadataTable->sizeOfIncludingThis(mallocSizeOf);
+  }
+
+  if (auto& map = nonSyntacticLexicalEnvironments_) {
+    *nonSyntacticLexicalEnvironmentsArg +=
+        map->sizeOfIncludingThis(mallocSizeOf);
+  }
+}
+
+void Realm::addSizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf,
+                                   size_t* realmObject, size_t* realmTables,
+                                   size_t* innerViewsArg,
+                                   size_t* objectMetadataTablesArg,
+                                   size_t* savedStacksSet,
+                                   size_t* nonSyntacticLexicalEnvironmentsArg) {
+  *realmObject += mallocSizeOf(this);
+  wasm.addSizeOfExcludingThis(mallocSizeOf, realmTables);
+
+  objects_.addSizeOfExcludingThis(mallocSizeOf, innerViewsArg,
+                                  objectMetadataTablesArg,
+                                  nonSyntacticLexicalEnvironmentsArg);
+
+  *savedStacksSet += savedStacks_.sizeOfExcludingThis(mallocSizeOf);
+}
+
+bool Realm::shouldCaptureStackForThrow() {
+  // Determine whether a stack trace should be captured for throw-statements (or
+  // similar) in JS code in this realm. We don't want to do this unconditionally
+  // because capturing stacks is slow and some scripts throw a lot of
+  // exceptions.
+  //
+  // Note: this is unrelated to Error.stack! That property is observable from
+  // JS code so we can't use these heuristics there. The code here is mostly
+  // relevant for uncaught exceptions that are not Error objects.
+
+  // To match other browsers, we always capture a stack trace if the realm is a
+  // debuggee (this includes the devtools console being open) or if unlimited
+  // stack traces have been enabled for this realm (used in automation).
+  if (isDebuggee() || isUnlimitedStacksCapturingEnabled) {
+    return true;
+  }
+
+  // Also always capture for chrome code. This is code we control and this helps
+  // debugging.
+  if (principals() &&
+      principals() == runtimeFromMainThread()->trustedPrincipals()) {
+    return true;
+  }
+
+  // Else, capture the stack only for the first N exceptions so that we can
+  // still show stack traces for scripts that don't throw a lot of exceptions
+  // (if the console is opened later).
+  static constexpr uint16_t MaxStacksCapturedForThrow = 50;
+  if (numStacksCapturedForThrow_ > MaxStacksCapturedForThrow) {
+    return false;
+  }
+  numStacksCapturedForThrow_++;
+  return true;
+}
+
+mozilla::HashCodeScrambler Realm::randomHashCodeScrambler() {
+  return mozilla::HashCodeScrambler(randomKeyGenerator_.next(),
+                                    randomKeyGenerator_.next());
+}
+
+void AutoSetNewObjectMetadata::setPendingMetadata() {
+  JSObject* obj = cx_->realm()->getAndClearObjectPendingMetadata();
+  if (!obj) {
+    return;
+  }
+
+  MOZ_ASSERT(obj->getClass()->shouldDelayMetadataBuilder());
+
+  if (cx_->isExceptionPending()) {
+    return;
+  }
+
+  // This function is called from a destructor that often runs upon exit from
+  // a function that is returning an unrooted pointer to a Cell. The
+  // allocation metadata callback often allocates; if it causes a GC, then the
+  // Cell pointer being returned won't be traced or relocated.
+  //
+  // The only extant callbacks are those internal to SpiderMonkey that
+  // capture the JS stack. In fact, we're considering removing general
+  // callbacks altogther in bug 1236748. Since it's not running arbitrary
+  // code, it's adequate to simply suppress GC while we run the callback.
+  gc::AutoSuppressGC autoSuppressGC(cx_);
+
+  (void)SetNewObjectMetadata(cx_, obj);
+}
+
+JS_PUBLIC_API void gc::TraceRealm(JSTracer* trc, JS::Realm* realm,
+                                  const char* name) {
+  // The way GC works with compartments is basically incomprehensible.
+  // For Realms, what we want is very simple: each Realm has a strong
+  // reference to its GlobalObject, and vice versa.
+  //
+  // Here we simply trace our side of that edge. During GC,
+  // GCRuntime::traceRuntimeCommon() marks all other realm roots, for
+  // all realms.
+  realm->traceGlobalData(trc);
+}
+
+JS_PUBLIC_API JS::Realm* JS::GetCurrentRealmOrNull(JSContext* cx) {
+  return cx->realm();
+}
+
+JS_PUBLIC_API JS::Realm* JS::GetObjectRealmOrNull(JSObject* obj) {
+  return IsCrossCompartmentWrapper(obj) ? nullptr : obj->nonCCWRealm();
+}
+
+JS_PUBLIC_API void* JS::GetRealmPrivate(JS::Realm* realm) {
+  return realm->realmPrivate();
+}
+
+JS_PUBLIC_API void JS::SetRealmPrivate(JS::Realm* realm, void* data) {
+  realm->setRealmPrivate(data);
+}
+
+JS_PUBLIC_API void JS::SetDestroyRealmCallback(
+    JSContext* cx, JS::DestroyRealmCallback callback) {
+  cx->runtime()->destroyRealmCallback = callback;
+}
+
+JS_PUBLIC_API void JS::SetRealmNameCallback(JSContext* cx,
+                                            JS::RealmNameCallback callback) {
+  cx->runtime()->realmNameCallback = callback;
+}
+
+JS_PUBLIC_API JSObject* JS::GetRealmGlobalOrNull(JS::Realm* realm) {
+  return realm->maybeGlobal();
+}
+
+JS_PUBLIC_API bool JS::InitRealmStandardClasses(JSContext* cx) {
+  MOZ_ASSERT(!cx->zone()->isAtomsZone());
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return GlobalObject::initStandardClasses(cx, cx->global());
+}
+
+JS_PUBLIC_API bool JS::MaybeFreezeCtorAndPrototype(JSContext* cx,
+                                                   HandleObject ctor,
+                                                   HandleObject maybeProto) {
+  if (MOZ_LIKELY(!cx->realm()->creationOptions().freezeBuiltins())) {
+    return true;
+  }
+  if (!SetIntegrityLevel(cx, ctor, IntegrityLevel::Frozen)) {
+    return false;
+  }
+  if (maybeProto) {
+    if (!SetIntegrityLevel(cx, maybeProto, IntegrityLevel::Sealed)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+JS_PUBLIC_API JSObject* JS::GetRealmObjectPrototype(JSContext* cx) {
+  CHECK_THREAD(cx);
+  return &cx->global()->getObjectPrototype();
+}
+
+JS_PUBLIC_API JS::Handle<JSObject*> JS::GetRealmObjectPrototypeHandle(
+    JSContext* cx) {
+  return cx->global()->getObjectPrototypeHandle();
+}
+
+JS_PUBLIC_API JSObject* JS::GetRealmFunctionPrototype(JSContext* cx) {
+  CHECK_THREAD(cx);
+  return &cx->global()->getFunctionPrototype();
+}
+
+JS_PUBLIC_API JSObject* JS::GetRealmArrayPrototype(JSContext* cx) {
+  CHECK_THREAD(cx);
+  return GlobalObject::getOrCreateArrayPrototype(cx, cx->global());
+}
+
+JS_PUBLIC_API JSObject* JS::GetRealmErrorPrototype(JSContext* cx) {
+  CHECK_THREAD(cx);
+  return GlobalObject::getOrCreateCustomErrorPrototype(cx, cx->global(),
+                                                       JSEXN_ERR);
+}
+
+JS_PUBLIC_API JSObject* JS::GetRealmIteratorPrototype(JSContext* cx) {
+  CHECK_THREAD(cx);
+  return GlobalObject::getOrCreateIteratorPrototype(cx, cx->global());
+}
+
+JS_PUBLIC_API JSObject* JS::GetRealmAsyncIteratorPrototype(JSContext* cx) {
+  CHECK_THREAD(cx);
+  return GlobalObject::getOrCreateAsyncIteratorPrototype(cx, cx->global());
+}
+
+JS_PUBLIC_API JSObject* JS::GetRealmKeyObject(JSContext* cx) {
+  return GlobalObject::getOrCreateRealmKeyObject(cx, cx->global());
+}
+
+JS_PUBLIC_API Realm* JS::GetFunctionRealm(JSContext* cx, HandleObject objArg) {
+  // https://tc39.github.io/ecma262/#sec-getfunctionrealm
+  // 7.3.22 GetFunctionRealm ( obj )
+
+  CHECK_THREAD(cx);
+  cx->check(objArg);
+
+  RootedObject obj(cx, objArg);
+  while (true) {
+    obj = CheckedUnwrapStatic(obj);
+    if (!obj) {
+      ReportAccessDenied(cx);
+      return nullptr;
+    }
+
+    // Step 1.
+    MOZ_ASSERT(IsCallable(obj));
+
+    // Steps 2 and 3. We use a loop instead of recursion to unwrap bound
+    // functions.
+    if (obj->is<JSFunction>()) {
+      return obj->as<JSFunction>().realm();
+    }
+    if (obj->is<BoundFunctionObject>()) {
+      obj = obj->as<BoundFunctionObject>().getTarget();
+      continue;
+    }
+
+    // WrappedFunctionObjects also have a [[Realm]] internal slot,
+    // which is the nonCCWRealm by construction.
+    if (obj->is<WrappedFunctionObject>()) {
+      return obj->nonCCWRealm();
+    }
+
+    // Step 4.
+    if (IsScriptedProxy(obj)) {
+      // Steps 4.a-b.
+      JSObject* proxyTarget = GetProxyTargetObject(obj);
+      if (!proxyTarget) {
+        JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
+                                  JSMSG_PROXY_REVOKED);
+        return nullptr;
+      }
+
+      // Step 4.c.
+      obj = proxyTarget;
+      continue;
+    }
+
+    // Step 5.
+    return cx->realm();
+  }
+}