js/xpconnect/src/XPCJSRuntime.cpp
author Ryan VanderMeulen <ryanvm@gmail.com>
Fri, 18 Aug 2017 11:32:18 -0400
changeset 375654 399db8547abb4549b05ffd419fab29c8cbd6c2ae
parent 375599 805c568069301ae91ead5780cdc118af73907229
child 375676 4b9185a04fe62a75a5a5b97947cb47f81ba2bfd3
permissions -rw-r--r--
Backed out 8 changesets (bug 1356334) for frequent test_ext_contentscript_async_loading.html failures on Android debug on a CLOSED TREE. Backed out changeset 9c677ebfdda0 (bug 1356334) Backed out changeset 16b49fd1c38a (bug 1356334) Backed out changeset 4f5bcd2b2dc6 (bug 1356334) Backed out changeset d832803270ac (bug 1356334) Backed out changeset b83aea215a82 (bug 1356334) Backed out changeset b2a663ffd144 (bug 1356334) Backed out changeset 805c56806930 (bug 1356334) Backed out changeset 7c880eca810a (bug 1356334)

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim: set ts=8 sts=4 et sw=4 tw=99: */
/* 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/. */

/* Per JSRuntime object */

#include "mozilla/MemoryReporting.h"
#include "mozilla/UniquePtr.h"

#include "xpcprivate.h"
#include "xpcpublic.h"
#include "XPCWrapper.h"
#include "XPCJSMemoryReporter.h"
#include "WrapperFactory.h"
#include "mozJSComponentLoader.h"
#include "nsAutoPtr.h"
#include "nsNetUtil.h"

#include "nsIMemoryInfoDumper.h"
#include "nsIMemoryReporter.h"
#include "nsIObserverService.h"
#include "nsIDebug2.h"
#include "nsIDocShell.h"
#include "nsIRunnable.h"
#include "amIAddonManager.h"
#include "nsPIDOMWindow.h"
#include "nsPrintfCString.h"
#include "mozilla/Preferences.h"
#include "mozilla/Telemetry.h"
#include "mozilla/Services.h"
#include "mozilla/dom/ScriptLoader.h"
#include "mozilla/dom/ScriptSettings.h"

#include "nsContentUtils.h"
#include "nsCCUncollectableMarker.h"
#include "nsCycleCollectionNoteRootCallback.h"
#include "nsCycleCollector.h"
#include "jsapi.h"
#include "jsprf.h"
#include "js/MemoryMetrics.h"
#include "mozilla/dom/GeneratedAtomList.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/Element.h"
#include "mozilla/dom/WindowBinding.h"
#include "mozilla/jsipc/CrossProcessObjectWrappers.h"
#include "mozilla/Atomics.h"
#include "mozilla/Attributes.h"
#include "mozilla/ProcessHangMonitor.h"
#include "mozilla/Sprintf.h"
#include "mozilla/UniquePtrExtensions.h"
#include "mozilla/Unused.h"
#include "AccessCheck.h"
#include "nsGlobalWindow.h"
#include "nsAboutProtocolUtils.h"

#include "GeckoProfiler.h"
#include "nsIInputStream.h"
#include "nsIXULRuntime.h"
#include "nsJSPrincipals.h"

#ifdef MOZ_CRASHREPORTER
#include "nsExceptionHandler.h"
#endif

#ifdef XP_WIN
#include <windows.h>
#endif

using namespace mozilla;
using namespace xpc;
using namespace JS;
using mozilla::dom::PerThreadAtomCache;
using mozilla::dom::AutoEntryScript;

/***************************************************************************/

const char* const XPCJSRuntime::mStrings[] = {
    "constructor",          // IDX_CONSTRUCTOR
    "toString",             // IDX_TO_STRING
    "toSource",             // IDX_TO_SOURCE
    "lastResult",           // IDX_LAST_RESULT
    "returnCode",           // IDX_RETURN_CODE
    "value",                // IDX_VALUE
    "QueryInterface",       // IDX_QUERY_INTERFACE
    "Components",           // IDX_COMPONENTS
    "wrappedJSObject",      // IDX_WRAPPED_JSOBJECT
    "Object",               // IDX_OBJECT
    "Function",             // IDX_FUNCTION
    "prototype",            // IDX_PROTOTYPE
    "createInstance",       // IDX_CREATE_INSTANCE
    "item",                 // IDX_ITEM
    "__proto__",            // IDX_PROTO
    "__iterator__",         // IDX_ITERATOR
    "__exposedProps__",     // IDX_EXPOSEDPROPS
    "eval",                 // IDX_EVAL
    "controllers",          // IDX_CONTROLLERS
    "Controllers",          // IDX_CONTROLLERS_CLASS
    "realFrameElement",     // IDX_REALFRAMEELEMENT
    "length",               // IDX_LENGTH
    "name",                 // IDX_NAME
    "undefined",            // IDX_UNDEFINED
    "",                     // IDX_EMPTYSTRING
    "fileName",             // IDX_FILENAME
    "lineNumber",           // IDX_LINENUMBER
    "columnNumber",         // IDX_COLUMNNUMBER
    "stack",                // IDX_STACK
    "message",              // IDX_MESSAGE
    "lastIndex"             // IDX_LASTINDEX
};

/***************************************************************************/

// *Some* NativeSets are referenced from mClassInfo2NativeSetMap.
// *All* NativeSets are referenced from mNativeSetMap.
// So, in mClassInfo2NativeSetMap we just clear references to the unmarked.
// In mNativeSetMap we clear the references to the unmarked *and* delete them.

class AsyncFreeSnowWhite : public Runnable
{
public:
  NS_IMETHOD Run() override
  {
      TimeStamp start = TimeStamp::Now();
      bool hadSnowWhiteObjects = nsCycleCollector_doDeferredDeletion();
      Telemetry::Accumulate(Telemetry::CYCLE_COLLECTOR_ASYNC_SNOW_WHITE_FREEING,
                            uint32_t((TimeStamp::Now() - start).ToMilliseconds()));
      if (hadSnowWhiteObjects && !mContinuation) {
          mContinuation = true;
          if (NS_FAILED(Dispatch())) {
              mActive = false;
          }
      } else {
          mActive = false;
      }
      return NS_OK;
  }

  nsresult Dispatch()
  {
      nsCOMPtr<nsIRunnable> self(this);
      return NS_IdleDispatchToCurrentThread(self.forget(), 2500);
  }

  void Start(bool aContinuation = false, bool aPurge = false)
  {
      if (mContinuation) {
          mContinuation = aContinuation;
      }
      mPurge = aPurge;
      if (!mActive && NS_SUCCEEDED(Dispatch())) {
          mActive = true;
      }
  }

  AsyncFreeSnowWhite()
    : Runnable("AsyncFreeSnowWhite")
    , mContinuation(false)
    , mActive(false)
    , mPurge(false) {}

public:
  bool mContinuation;
  bool mActive;
  bool mPurge;
};

namespace xpc {

CompartmentPrivate::CompartmentPrivate(JSCompartment* c)
    : wantXrays(false)
    , allowWaivers(true)
    , writeToGlobalPrototype(false)
    , skipWriteToGlobalPrototype(false)
    , isWebExtensionContentScript(false)
    , waiveInterposition(false)
    , addonCallInterposition(false)
    , allowCPOWs(false)
    , universalXPConnectEnabled(false)
    , forcePermissiveCOWs(false)
    , wasNuked(false)
    , scriptability(c)
    , scope(nullptr)
    , mWrappedJSMap(JSObject2WrappedJSMap::newMap(XPC_JS_MAP_LENGTH))
{
    MOZ_COUNT_CTOR(xpc::CompartmentPrivate);
    mozilla::PodArrayZero(wrapperDenialWarnings);
}

CompartmentPrivate::~CompartmentPrivate()
{
    MOZ_COUNT_DTOR(xpc::CompartmentPrivate);
    mWrappedJSMap->ShutdownMarker();
    delete mWrappedJSMap;
}

static bool
TryParseLocationURICandidate(const nsACString& uristr,
                             CompartmentPrivate::LocationHint aLocationHint,
                             nsIURI** aURI)
{
    static NS_NAMED_LITERAL_CSTRING(kGRE, "resource://gre/");
    static NS_NAMED_LITERAL_CSTRING(kToolkit, "chrome://global/");
    static NS_NAMED_LITERAL_CSTRING(kBrowser, "chrome://browser/");

    if (aLocationHint == CompartmentPrivate::LocationHintAddon) {
        // Blacklist some known locations which are clearly not add-on related.
        if (StringBeginsWith(uristr, kGRE) ||
            StringBeginsWith(uristr, kToolkit) ||
            StringBeginsWith(uristr, kBrowser))
            return false;

        // -- GROSS HACK ALERT --
        // The Yandex Elements 8.10.2 extension implements its own "xb://" URL
        // scheme. If we call NS_NewURI() on an "xb://..." URL, we'll end up
        // calling into the extension's own JS-implemented nsIProtocolHandler
        // object, which we can't allow while we're iterating over the JS heap.
        // So just skip any such URL.
        // -- GROSS HACK ALERT --
        if (StringBeginsWith(uristr, NS_LITERAL_CSTRING("xb")))
            return false;
    }

    nsCOMPtr<nsIURI> uri;
    if (NS_FAILED(NS_NewURI(getter_AddRefs(uri), uristr)))
        return false;

    nsAutoCString scheme;
    if (NS_FAILED(uri->GetScheme(scheme)))
        return false;

    // Cannot really map data: and blob:.
    // Also, data: URIs are pretty memory hungry, which is kinda bad
    // for memory reporter use.
    if (scheme.EqualsLiteral("data") || scheme.EqualsLiteral("blob"))
        return false;

    uri.forget(aURI);
    return true;
}

bool CompartmentPrivate::TryParseLocationURI(CompartmentPrivate::LocationHint aLocationHint,
                                             nsIURI** aURI)
{
    if (!aURI)
        return false;

    // Need to parse the URI.
    if (location.IsEmpty())
        return false;

    // Handle Sandbox location strings.
    // A sandbox string looks like this, for anonymous sandboxes, and builds
    // where Sandbox location tagging is enabled:
    //
    // <sandboxName> (from: <js-stack-frame-filename>:<lineno>)
    //
    // where <sandboxName> is user-provided via Cu.Sandbox()
    // and <js-stack-frame-filename> and <lineno> is the stack frame location
    // from where Cu.Sandbox was called.
    //
    // Otherwise, it is simply the caller-provided name, which is usually a URI.
    //
    // <js-stack-frame-filename> furthermore is "free form", often using a
    // "uri -> uri -> ..." chain. The following code will and must handle this
    // common case.
    //
    // It should be noted that other parts of the code may already rely on the
    // "format" of these strings.

    static const nsDependentCString from("(from: ");
    static const nsDependentCString arrow(" -> ");
    static const size_t fromLength = from.Length();
    static const size_t arrowLength = arrow.Length();

    // See: XPCComponents.cpp#AssembleSandboxMemoryReporterName
    int32_t idx = location.Find(from);
    if (idx < 0)
        return TryParseLocationURICandidate(location, aLocationHint, aURI);


    // When parsing we're looking for the right-most URI. This URI may be in
    // <sandboxName>, so we try this first.
    if (TryParseLocationURICandidate(Substring(location, 0, idx), aLocationHint,
                                     aURI))
        return true;

    // Not in <sandboxName> so we need to inspect <js-stack-frame-filename> and
    // the chain that is potentially contained within and grab the rightmost
    // item that is actually a URI.

    // First, hack off the :<lineno>) part as well
    int32_t ridx = location.RFind(NS_LITERAL_CSTRING(":"));
    nsAutoCString chain(Substring(location, idx + fromLength,
                                  ridx - idx - fromLength));

    // Loop over the "->" chain. This loop also works for non-chains, or more
    // correctly chains with only one item.
    for (;;) {
        idx = chain.RFind(arrow);
        if (idx < 0) {
            // This is the last chain item. Try to parse what is left.
            return TryParseLocationURICandidate(chain, aLocationHint, aURI);
        }

        // Try to parse current chain item
        if (TryParseLocationURICandidate(Substring(chain, idx + arrowLength),
                                         aLocationHint, aURI))
            return true;

        // Current chain item couldn't be parsed.
        // Strip current item and continue.
        chain = Substring(chain, 0, idx);
    }

    MOZ_CRASH("Chain parser loop does not terminate");
}

static bool
PrincipalImmuneToScriptPolicy(nsIPrincipal* aPrincipal)
{
    // System principal gets a free pass.
    if (nsXPConnect::SecurityManager()->IsSystemPrincipal(aPrincipal))
        return true;

    // ExpandedPrincipal gets a free pass.
    nsCOMPtr<nsIExpandedPrincipal> ep = do_QueryInterface(aPrincipal);
    if (ep)
        return true;

    // Check whether our URI is an "about:" URI that allows scripts.  If it is,
    // we need to allow JS to run.
    nsCOMPtr<nsIURI> principalURI;
    aPrincipal->GetURI(getter_AddRefs(principalURI));
    MOZ_ASSERT(principalURI);

    // WebExtension principals gets a free pass.
    nsString addonId;
    aPrincipal->GetAddonId(addonId);
    bool isWebExtension = !addonId.IsEmpty();
    if (isWebExtension) {
        return true;
    }

    bool isAbout;
    nsresult rv = principalURI->SchemeIs("about", &isAbout);
    if (NS_SUCCEEDED(rv) && isAbout) {
        nsCOMPtr<nsIAboutModule> module;
        rv = NS_GetAboutModule(principalURI, getter_AddRefs(module));
        if (NS_SUCCEEDED(rv)) {
            uint32_t flags;
            rv = module->GetURIFlags(principalURI, &flags);
            if (NS_SUCCEEDED(rv) &&
                (flags & nsIAboutModule::ALLOW_SCRIPT)) {
                return true;
            }
        }
    }

    return false;
}

Scriptability::Scriptability(JSCompartment* c) : mScriptBlocks(0)
                                               , mDocShellAllowsScript(true)
                                               , mScriptBlockedByPolicy(false)
{
    nsIPrincipal* prin = nsJSPrincipals::get(JS_GetCompartmentPrincipals(c));
    mImmuneToScriptPolicy = PrincipalImmuneToScriptPolicy(prin);

    // If we're not immune, we should have a real principal with a codebase URI.
    // Check the URI against the new-style domain policy.
    if (!mImmuneToScriptPolicy) {
        nsCOMPtr<nsIURI> codebase;
        nsresult rv = prin->GetURI(getter_AddRefs(codebase));
        bool policyAllows;
        if (NS_SUCCEEDED(rv) && codebase &&
            NS_SUCCEEDED(nsXPConnect::SecurityManager()->PolicyAllowsScript(codebase, &policyAllows)))
        {
            mScriptBlockedByPolicy = !policyAllows;
        } else {
            // Something went wrong - be safe and block script.
            mScriptBlockedByPolicy = true;
        }
    }
}

bool
Scriptability::Allowed()
{
    return mDocShellAllowsScript && !mScriptBlockedByPolicy &&
           mScriptBlocks == 0;
}

bool
Scriptability::IsImmuneToScriptPolicy()
{
    return mImmuneToScriptPolicy;
}

void
Scriptability::Block()
{
    ++mScriptBlocks;
}

void
Scriptability::Unblock()
{
    MOZ_ASSERT(mScriptBlocks > 0);
    --mScriptBlocks;
}

void
Scriptability::SetDocShellAllowsScript(bool aAllowed)
{
    mDocShellAllowsScript = aAllowed || mImmuneToScriptPolicy;
}

/* static */
Scriptability&
Scriptability::Get(JSObject* aScope)
{
    return CompartmentPrivate::Get(aScope)->scriptability;
}

bool
IsContentXBLScope(JSCompartment* compartment)
{
    // We always eagerly create compartment privates for XBL scopes.
    CompartmentPrivate* priv = CompartmentPrivate::Get(compartment);
    if (!priv || !priv->scope)
        return false;
    return priv->scope->IsContentXBLScope();
}

bool
IsInContentXBLScope(JSObject* obj)
{
    return IsContentXBLScope(js::GetObjectCompartment(obj));
}

bool
IsInAddonScope(JSObject* obj)
{
    return ObjectScope(obj)->IsAddonScope();
}

bool
IsUniversalXPConnectEnabled(JSCompartment* compartment)
{
    CompartmentPrivate* priv = CompartmentPrivate::Get(compartment);
    if (!priv)
        return false;
    return priv->universalXPConnectEnabled;
}

bool
IsUniversalXPConnectEnabled(JSContext* cx)
{
    JSCompartment* compartment = js::GetContextCompartment(cx);
    if (!compartment)
        return false;
    return IsUniversalXPConnectEnabled(compartment);
}

bool
EnableUniversalXPConnect(JSContext* cx)
{
    JSCompartment* compartment = js::GetContextCompartment(cx);
    if (!compartment)
        return true;
    // Never set universalXPConnectEnabled on a chrome compartment - it confuses
    // the security wrapping code.
    if (AccessCheck::isChrome(compartment))
        return true;
    CompartmentPrivate* priv = CompartmentPrivate::Get(compartment);
    if (!priv)
        return true;
    if (priv->universalXPConnectEnabled)
        return true;
    priv->universalXPConnectEnabled = true;

    // Recompute all the cross-compartment wrappers leaving the newly-privileged
    // compartment.
    bool ok = js::RecomputeWrappers(cx, js::SingleCompartment(compartment),
                                    js::AllCompartments());
    NS_ENSURE_TRUE(ok, false);

    // The Components object normally isn't defined for unprivileged web content,
    // but we define it when UniversalXPConnect is enabled to support legacy
    // tests.
    XPCWrappedNativeScope* scope = priv->scope;
    if (!scope)
        return true;
    scope->ForcePrivilegedComponents();
    return scope->AttachComponentsObject(cx);
}

JSObject*
UnprivilegedJunkScope()
{
    return XPCJSRuntime::Get()->UnprivilegedJunkScope();
}

JSObject*
PrivilegedJunkScope()
{
    return XPCJSRuntime::Get()->PrivilegedJunkScope();
}

JSObject*
CompilationScope()
{
    return XPCJSRuntime::Get()->CompilationScope();
}

nsGlobalWindow*
WindowOrNull(JSObject* aObj)
{
    MOZ_ASSERT(aObj);
    MOZ_ASSERT(!js::IsWrapper(aObj));

    nsGlobalWindow* win = nullptr;
    UNWRAP_NON_WRAPPER_OBJECT(Window, aObj, win);
    return win;
}

nsGlobalWindow*
WindowGlobalOrNull(JSObject* aObj)
{
    MOZ_ASSERT(aObj);
    JSObject* glob = js::GetGlobalForObjectCrossCompartment(aObj);

    return WindowOrNull(glob);
}

nsGlobalWindow*
AddonWindowOrNull(JSObject* aObj)
{
    if (!IsInAddonScope(aObj))
        return nullptr;

    JSObject* global = js::GetGlobalForObjectCrossCompartment(aObj);
    JSObject* proto = js::GetPrototypeNoProxy(global);

    // Addons could theoretically change the prototype of the addon scope, but
    // we pretty much just want to crash if that happens so that we find out
    // about it and get them to change their code.
    MOZ_RELEASE_ASSERT(js::IsCrossCompartmentWrapper(proto) ||
                       xpc::IsSandboxPrototypeProxy(proto));
    JSObject* mainGlobal = js::UncheckedUnwrap(proto, /* stopAtWindowProxy = */ false);
    MOZ_RELEASE_ASSERT(JS_IsGlobalObject(mainGlobal));

    return WindowOrNull(mainGlobal);
}

nsGlobalWindow*
CurrentWindowOrNull(JSContext* cx)
{
    JSObject* glob = JS::CurrentGlobalOrNull(cx);
    return glob ? WindowOrNull(glob) : nullptr;
}

// Nukes all wrappers into or out of the given compartment, and prevents new
// wrappers from being created. Additionally marks the compartment as
// unscriptable after wrappers have been nuked.
//
// Note: This should *only* be called for browser or extension compartments.
// Wrappers between web compartments must never be cut in web-observable
// ways.
void
NukeAllWrappersForCompartment(JSContext* cx, JSCompartment* compartment,
                              js::NukeReferencesToWindow nukeReferencesToWindow)
{
    // First, nuke all wrappers into or out of the target compartment. Once
    // the compartment is marked as nuked, WrapperFactory will refuse to
    // create new live wrappers for it, in either direction. This means that
    // we need to be sure that we don't have any existing cross-compartment
    // wrappers which may be replaced with dead wrappers during unrelated
    // wrapper recomputation *before* we set that bit.
    js::NukeCrossCompartmentWrappers(cx, js::AllCompartments(), compartment,
                                     nukeReferencesToWindow,
                                     js::NukeAllReferences);

    // At this point, we should cross-compartment wrappers for the nuked
    // compartment. Set the wasNuked bit so WrapperFactory will return a
    // DeadObjectProxy when asked to create a new wrapper for it, and mark as
    // unscriptable.
    auto compartmentPrivate = xpc::CompartmentPrivate::Get(compartment);
    compartmentPrivate->wasNuked = true;
    compartmentPrivate->scriptability.Block();
}

} // namespace xpc

static void
CompartmentDestroyedCallback(JSFreeOp* fop, JSCompartment* compartment)
{
    // NB - This callback may be called in JS_DestroyContext, which happens
    // after the XPCJSRuntime has been torn down.

    // Get the current compartment private into an AutoPtr (which will do the
    // cleanup for us), and null out the private (which may already be null).
    nsAutoPtr<CompartmentPrivate> priv(CompartmentPrivate::Get(compartment));
    JS_SetCompartmentPrivate(compartment, nullptr);
}

static size_t
CompartmentSizeOfIncludingThisCallback(MallocSizeOf mallocSizeOf, JSCompartment* compartment)
{
    CompartmentPrivate* priv = CompartmentPrivate::Get(compartment);
    return priv ? priv->SizeOfIncludingThis(mallocSizeOf) : 0;
}

/*
 * Return true if there exists a non-system inner window which is a current
 * inner window and whose reflector is gray.  We don't merge system
 * compartments, so we don't use them to trigger merging CCs.
 */
bool XPCJSRuntime::UsefulToMergeZones() const
{
    MOZ_ASSERT(NS_IsMainThread());

    // Turns out, actually making this return true often enough makes Windows
    // mochitest-gl OOM a lot.  Need to figure out what's going on there; see
    // bug 1277036.

    return false;
}

void XPCJSRuntime::TraceNativeBlackRoots(JSTracer* trc)
{
    for (CycleCollectedJSContext* ccx : Contexts()) {
        auto* cx = static_cast<const XPCJSContext*>(ccx);
        if (AutoMarkingPtr* roots = cx->mAutoRoots)
            roots->TraceJSAll(trc);
    }

    JSContext* cx = XPCJSContext::Get()->Context();
    dom::TraceBlackJS(trc, JS_GetGCParameter(cx, JSGC_NUMBER),
                      nsXPConnect::XPConnect()->IsShuttingDown());
}

void XPCJSRuntime::TraceAdditionalNativeGrayRoots(JSTracer* trc)
{
    XPCWrappedNativeScope::TraceWrappedNativesInAllScopes(trc);

    for (XPCRootSetElem* e = mVariantRoots; e ; e = e->GetNextRoot())
        static_cast<XPCTraceableVariant*>(e)->TraceJS(trc);

    for (XPCRootSetElem* e = mWrappedJSRoots; e ; e = e->GetNextRoot())
        static_cast<nsXPCWrappedJS*>(e)->TraceJS(trc);
}

void
XPCJSRuntime::TraverseAdditionalNativeRoots(nsCycleCollectionNoteRootCallback& cb)
{
    XPCWrappedNativeScope::SuspectAllWrappers(cb);

    for (XPCRootSetElem* e = mVariantRoots; e ; e = e->GetNextRoot()) {
        XPCTraceableVariant* v = static_cast<XPCTraceableVariant*>(e);
        if (nsCCUncollectableMarker::InGeneration(cb,
                                                  v->CCGeneration())) {
           JS::Value val = v->GetJSValPreserveColor();
           if (val.isObject() && !JS::ObjectIsMarkedGray(&val.toObject()))
               continue;
        }
        cb.NoteXPCOMRoot(v,
                         XPCTraceableVariant::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant());
    }

    for (XPCRootSetElem* e = mWrappedJSRoots; e ; e = e->GetNextRoot()) {
        cb.NoteXPCOMRoot(ToSupports(static_cast<nsXPCWrappedJS*>(e)),
                         nsXPCWrappedJS::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant());
    }
}

void
XPCJSRuntime::UnmarkSkippableJSHolders()
{
    CycleCollectedJSRuntime::UnmarkSkippableJSHolders();
}

void
XPCJSRuntime::PrepareForForgetSkippable()
{
    nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
    if (obs) {
        obs->NotifyObservers(nullptr, "cycle-collector-forget-skippable", nullptr);
    }
}

void
XPCJSRuntime::BeginCycleCollectionCallback()
{
    nsJSContext::BeginCycleCollectionCallback();

    nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
    if (obs) {
        obs->NotifyObservers(nullptr, "cycle-collector-begin", nullptr);
    }
}

void
XPCJSRuntime::EndCycleCollectionCallback(CycleCollectorResults& aResults)
{
    nsJSContext::EndCycleCollectionCallback(aResults);

    nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
    if (obs) {
        obs->NotifyObservers(nullptr, "cycle-collector-end", nullptr);
    }
}

void
XPCJSRuntime::DispatchDeferredDeletion(bool aContinuation, bool aPurge)
{
    mAsyncSnowWhiteFreer->Start(aContinuation, aPurge);
}

void
xpc_UnmarkSkippableJSHolders()
{
    if (nsXPConnect::GetRuntimeInstance()) {
        nsXPConnect::GetRuntimeInstance()->UnmarkSkippableJSHolders();
    }
}

/* static */ void
XPCJSRuntime::GCSliceCallback(JSContext* cx,
                              JS::GCProgress progress,
                              const JS::GCDescription& desc)
{
    XPCJSRuntime* self = nsXPConnect::GetRuntimeInstance();
    if (!self)
        return;

#ifdef MOZ_CRASHREPORTER
    CrashReporter::SetGarbageCollecting(progress == JS::GC_CYCLE_BEGIN);
#endif

    if (self->mPrevGCSliceCallback)
        (*self->mPrevGCSliceCallback)(cx, progress, desc);
}

/* static */ void
XPCJSRuntime::DoCycleCollectionCallback(JSContext* cx)
{
    // The GC has detected that a CC at this point would collect a tremendous
    // amount of garbage that is being revivified unnecessarily.
    NS_DispatchToCurrentThread(
      NS_NewRunnableFunction("XPCJSRuntime::DoCycleCollectionCallback",
                             []() { nsJSContext::CycleCollectNow(nullptr); }));

    XPCJSRuntime* self = nsXPConnect::GetRuntimeInstance();
    if (!self)
        return;

    if (self->mPrevDoCycleCollectionCallback)
        (*self->mPrevDoCycleCollectionCallback)(cx);
}

void
XPCJSRuntime::CustomGCCallback(JSGCStatus status)
{
    nsTArray<xpcGCCallback> callbacks(extraGCCallbacks);
    for (uint32_t i = 0; i < callbacks.Length(); ++i)
        callbacks[i](status);
}

/* static */ void
XPCJSRuntime::FinalizeCallback(JSFreeOp* fop,
                               JSFinalizeStatus status,
                               bool isZoneGC,
                               void* data)
{
    XPCJSRuntime* self = nsXPConnect::GetRuntimeInstance();
    if (!self)
        return;

    switch (status) {
        case JSFINALIZE_GROUP_PREPARE:
        {
            MOZ_ASSERT(!self->mDoingFinalization, "bad state");

            MOZ_ASSERT(!self->mGCIsRunning, "bad state");
            self->mGCIsRunning = true;

            self->mDoingFinalization = true;

            break;
        }
        case JSFINALIZE_GROUP_START:
        {
            MOZ_ASSERT(self->mDoingFinalization, "bad state");

            MOZ_ASSERT(self->mGCIsRunning, "bad state");
            self->mGCIsRunning = false;

            break;
        }
        case JSFINALIZE_GROUP_END:
        {
            // Sweep scopes needing cleanup
            XPCWrappedNativeScope::KillDyingScopes();

            MOZ_ASSERT(self->mDoingFinalization, "bad state");
            self->mDoingFinalization = false;

            break;
        }
        case JSFINALIZE_COLLECTION_END:
        {
            MOZ_ASSERT(!self->mGCIsRunning, "bad state");
            self->mGCIsRunning = true;

            for (CycleCollectedJSContext* ccx : self->Contexts()) {
                auto* cx = static_cast<const XPCJSContext*>(ccx);
                if (AutoMarkingPtr* roots = cx->mAutoRoots)
                    roots->MarkAfterJSFinalizeAll();

                // Now we are going to recycle any unused WrappedNativeTearoffs.
                // We do this by iterating all the live callcontexts
                // and marking the tearoffs in use. And then we
                // iterate over all the WrappedNative wrappers and sweep their
                // tearoffs.
                //
                // This allows us to perhaps minimize the growth of the
                // tearoffs. And also makes us not hold references to interfaces
                // on our wrapped natives that we are not actually using.
                //
                // XXX We may decide to not do this on *every* gc cycle.

                XPCCallContext* ccxp = cx->GetCallContext();
                while (ccxp) {
                    // Deal with the strictness of callcontext that
                    // complains if you ask for a tearoff when
                    // it is in a state where the tearoff could not
                    // possibly be valid.
                    if (ccxp->CanGetTearOff()) {
                        XPCWrappedNativeTearOff* to =
                            ccxp->GetTearOff();
                        if (to)
                            to->Mark();
                    }
                    ccxp = ccxp->GetPrevCallContext();
                }
            }

            XPCWrappedNativeScope::SweepAllWrappedNativeTearOffs();

            // Now we need to kill the 'Dying' XPCWrappedNativeProtos.
            // We transfered these native objects to this table when their
            // JSObject's were finalized. We did not destroy them immediately
            // at that point because the ordering of JS finalization is not
            // deterministic and we did not yet know if any wrappers that
            // might still be referencing the protos where still yet to be
            // finalized and destroyed. We *do* know that the protos'
            // JSObjects would not have been finalized if there were any
            // wrappers that referenced the proto but where not themselves
            // slated for finalization in this gc cycle. So... at this point
            // we know that any and all wrappers that might have been
            // referencing the protos in the dying list are themselves dead.
            // So, we can safely delete all the protos in the list.

            for (auto i = self->mDyingWrappedNativeProtoMap->Iter(); !i.Done(); i.Next()) {
                auto entry = static_cast<XPCWrappedNativeProtoMap::Entry*>(i.Get());
                delete static_cast<const XPCWrappedNativeProto*>(entry->key);
                i.Remove();
            }

            MOZ_ASSERT(self->mGCIsRunning, "bad state");
            self->mGCIsRunning = false;

            break;
        }
    }
}

/* static */ void
XPCJSRuntime::WeakPointerZonesCallback(JSContext* cx, void* data)
{
    // Called before each sweeping slice -- after processing any final marking
    // triggered by barriers -- to clear out any references to things that are
    // about to be finalized and update any pointers to moved GC things.
    XPCJSRuntime* self = static_cast<XPCJSRuntime*>(data);

    self->mWrappedJSMap->UpdateWeakPointersAfterGC();

    XPCWrappedNativeScope::UpdateWeakPointersInAllScopesAfterGC();
}

/* static */ void
XPCJSRuntime::WeakPointerCompartmentCallback(JSContext* cx, JSCompartment* comp, void* data)
{
    // Called immediately after the ZoneGroup weak pointer callback, but only
    // once for each compartment that is being swept.
    CompartmentPrivate* xpcComp = CompartmentPrivate::Get(comp);
    if (xpcComp)
        xpcComp->UpdateWeakPointersAfterGC();
}

void
CompartmentPrivate::UpdateWeakPointersAfterGC()
{
    mWrappedJSMap->UpdateWeakPointersAfterGC();
}

void
XPCJSRuntime::CustomOutOfMemoryCallback()
{
    if (!Preferences::GetBool("memory.dump_reports_on_oom")) {
        return;
    }

    nsCOMPtr<nsIMemoryInfoDumper> dumper =
        do_GetService("@mozilla.org/memory-info-dumper;1");
    if (!dumper) {
        return;
    }

    // If this fails, it fails silently.
    dumper->DumpMemoryInfoToTempDir(NS_LITERAL_STRING("due-to-JS-OOM"),
                                    /* anonymize = */ false,
                                    /* minimizeMemoryUsage = */ false);
}

void
XPCJSRuntime::OnLargeAllocationFailure()
{
    CycleCollectedJSRuntime::SetLargeAllocationFailure(OOMState::Reporting);

    nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
    if (os) {
        os->NotifyObservers(nullptr, "memory-pressure", u"heap-minimize");
    }

    CycleCollectedJSRuntime::SetLargeAllocationFailure(OOMState::Reported);
}

class LargeAllocationFailureRunnable final : public Runnable
{
    Mutex mMutex;
    CondVar mCondVar;
    bool mWaiting;

    virtual ~LargeAllocationFailureRunnable()
    {
        MOZ_ASSERT(!mWaiting);
    }

  protected:
    NS_IMETHOD Run() override
    {
        MOZ_ASSERT(NS_IsMainThread());

        XPCJSRuntime::Get()->OnLargeAllocationFailure();

        MutexAutoLock lock(mMutex);
        MOZ_ASSERT(mWaiting);

        mWaiting = false;
        mCondVar.Notify();
        return NS_OK;
    }

  public:
    LargeAllocationFailureRunnable()
      : mozilla::Runnable("LargeAllocationFailureRunnable")
      , mMutex("LargeAllocationFailureRunnable::mMutex")
      , mCondVar(mMutex, "LargeAllocationFailureRunnable::mCondVar")
      , mWaiting(true)
    {
        MOZ_ASSERT(!NS_IsMainThread());
    }

    void BlockUntilDone()
    {
        MOZ_ASSERT(!NS_IsMainThread());

        MutexAutoLock lock(mMutex);
        while (mWaiting) {
            mCondVar.Wait();
        }
    }
};

static void
OnLargeAllocationFailureCallback()
{
    // This callback can be called from any thread, including internal JS helper
    // and DOM worker threads. We need to send the low-memory event via the
    // observer service which can only be called on the main thread, so proxy to
    // the main thread if we're not there already. The purpose of this callback
    // is to synchronously free some memory so the caller can retry a failed
    // allocation, so block on the completion.

    if (NS_IsMainThread()) {
        XPCJSRuntime::Get()->OnLargeAllocationFailure();
        return;
    }

    RefPtr<LargeAllocationFailureRunnable> r = new LargeAllocationFailureRunnable;
    if (NS_WARN_IF(NS_FAILED(NS_DispatchToMainThread(r)))) {
        return;
    }

    r->BlockUntilDone();
}

size_t
XPCJSRuntime::SizeOfIncludingThis(MallocSizeOf mallocSizeOf)
{
    size_t n = 0;
    n += mallocSizeOf(this);
    n += mWrappedJSMap->SizeOfIncludingThis(mallocSizeOf);
    n += mIID2NativeInterfaceMap->SizeOfIncludingThis(mallocSizeOf);
    n += mClassInfo2NativeSetMap->ShallowSizeOfIncludingThis(mallocSizeOf);
    n += mNativeSetMap->SizeOfIncludingThis(mallocSizeOf);

    n += CycleCollectedJSRuntime::SizeOfExcludingThis(mallocSizeOf);

    // There are other XPCJSRuntime members that could be measured; the above
    // ones have been seen by DMD to be worth measuring.  More stuff may be
    // added later.

    return n;
}

size_t
CompartmentPrivate::SizeOfIncludingThis(MallocSizeOf mallocSizeOf)
{
    size_t n = mallocSizeOf(this);
    n += mWrappedJSMap->SizeOfIncludingThis(mallocSizeOf);
    n += mWrappedJSMap->SizeOfWrappedJS(mallocSizeOf);
    return n;
}

/***************************************************************************/

void
XPCJSRuntime::Shutdown(JSContext* cx)
{
    // This destructor runs before ~CycleCollectedJSContext, which does the
    // actual JS_DestroyContext() call. But destroying the context triggers
    // one final GC, which can call back into the context with various
    // callbacks if we aren't careful. Null out the relevant callbacks.
    JS_RemoveFinalizeCallback(cx, FinalizeCallback);
    JS_RemoveWeakPointerZonesCallback(cx, WeakPointerZonesCallback);
    JS_RemoveWeakPointerCompartmentCallback(cx, WeakPointerCompartmentCallback);

    JS::SetGCSliceCallback(cx, mPrevGCSliceCallback);

    // We don't want to track wrapped JS roots after this point since we're
    // making them !IsValid anyway through SystemIsBeingShutDown.
    mWrappedJSRoots = nullptr;

    // clean up and destroy maps...
    mWrappedJSMap->ShutdownMarker();
    delete mWrappedJSMap;
    mWrappedJSMap = nullptr;

    delete mWrappedJSClassMap;
    mWrappedJSClassMap = nullptr;

    delete mIID2NativeInterfaceMap;
    mIID2NativeInterfaceMap = nullptr;

    delete mClassInfo2NativeSetMap;
    mClassInfo2NativeSetMap = nullptr;

    delete mNativeSetMap;
    mNativeSetMap = nullptr;

    delete mThisTranslatorMap;
    mThisTranslatorMap = nullptr;

    delete mDyingWrappedNativeProtoMap;
    mDyingWrappedNativeProtoMap = nullptr;

    CycleCollectedJSRuntime::Shutdown(cx);
}

XPCJSRuntime::~XPCJSRuntime()
{
    MOZ_COUNT_DTOR_INHERITED(XPCJSRuntime, CycleCollectedJSRuntime);
}

// If |*anonymizeID| is non-zero and this is a user compartment, the name will
// be anonymized.
static void
GetCompartmentName(JSCompartment* c, nsCString& name, int* anonymizeID,
                   bool replaceSlashes)
{
    if (js::IsAtomsCompartment(c)) {
        name.AssignLiteral("atoms");
    } else if (*anonymizeID && !js::IsSystemCompartment(c)) {
        name.AppendPrintf("<anonymized-%d>", *anonymizeID);
        *anonymizeID += 1;
    } else if (JSPrincipals* principals = JS_GetCompartmentPrincipals(c)) {
        nsresult rv = nsJSPrincipals::get(principals)->GetScriptLocation(name);
        if (NS_FAILED(rv)) {
            name.AssignLiteral("(unknown)");
        }

        // If the compartment's location (name) differs from the principal's
        // script location, append the compartment's location to allow
        // differentiation of multiple compartments owned by the same principal
        // (e.g. components owned by the system or null principal).
        CompartmentPrivate* compartmentPrivate = CompartmentPrivate::Get(c);
        if (compartmentPrivate) {
            const nsACString& location = compartmentPrivate->GetLocation();
            if (!location.IsEmpty() && !location.Equals(name)) {
                name.AppendLiteral(", ");
                name.Append(location);
            }
        }

        if (*anonymizeID) {
            // We might have a file:// URL that includes a path from the local
            // filesystem, which should be omitted if we're anonymizing.
            static const char* filePrefix = "file://";
            int filePos = name.Find(filePrefix);
            if (filePos >= 0) {
                int pathPos = filePos + strlen(filePrefix);
                int lastSlashPos = -1;
                for (int i = pathPos; i < int(name.Length()); i++) {
                    if (name[i] == '/' || name[i] == '\\') {
                        lastSlashPos = i;
                    }
                }
                if (lastSlashPos != -1) {
                    name.ReplaceASCII(pathPos, lastSlashPos - pathPos,
                                      "<anonymized>");
                } else {
                    // Something went wrong. Anonymize the entire path to be
                    // safe.
                    name.Truncate(pathPos);
                    name += "<anonymized?!>";
                }
            }

            // We might have a location like this:
            //   inProcessTabChildGlobal?ownedBy=http://www.example.com/
            // The owner should be omitted if it's not a chrome: URI and we're
            // anonymizing.
            static const char* ownedByPrefix =
                "inProcessTabChildGlobal?ownedBy=";
            int ownedByPos = name.Find(ownedByPrefix);
            if (ownedByPos >= 0) {
                const char* chrome = "chrome:";
                int ownerPos = ownedByPos + strlen(ownedByPrefix);
                const nsDependentCSubstring& ownerFirstPart =
                    Substring(name, ownerPos, strlen(chrome));
                if (!ownerFirstPart.EqualsASCII(chrome)) {
                    name.Truncate(ownerPos);
                    name += "<anonymized>";
                }
            }
        }

        // A hack: replace forward slashes with '\\' so they aren't
        // treated as path separators.  Users of the reporters
        // (such as about:memory) have to undo this change.
        if (replaceSlashes)
            name.ReplaceChar('/', '\\');
    } else {
        name.AssignLiteral("null-principal");
    }
}

extern void
xpc::GetCurrentCompartmentName(JSContext* cx, nsCString& name)
{
    RootedObject global(cx, JS::CurrentGlobalOrNull(cx));
    if (!global) {
        name.AssignLiteral("no global");
        return;
    }

    JSCompartment* compartment = GetObjectCompartment(global);
    int anonymizeID = 0;
    GetCompartmentName(compartment, name, &anonymizeID, false);
}

void
xpc::AddGCCallback(xpcGCCallback cb)
{
    XPCJSRuntime::Get()->AddGCCallback(cb);
}

void
xpc::RemoveGCCallback(xpcGCCallback cb)
{
    XPCJSRuntime::Get()->RemoveGCCallback(cb);
}

static int64_t
JSMainRuntimeGCHeapDistinguishedAmount()
{
    JSContext* cx = danger::GetJSContext();
    return int64_t(JS_GetGCParameter(cx, JSGC_TOTAL_CHUNKS)) *
           js::gc::ChunkSize;
}

static int64_t
JSMainRuntimeTemporaryPeakDistinguishedAmount()
{
    JSContext* cx = danger::GetJSContext();
    return JS::PeakSizeOfTemporary(cx);
}

static int64_t
JSMainRuntimeCompartmentsSystemDistinguishedAmount()
{
    JSContext* cx = danger::GetJSContext();
    return JS::SystemCompartmentCount(cx);
}

static int64_t
JSMainRuntimeCompartmentsUserDistinguishedAmount()
{
    JSContext* cx = XPCJSContext::Get()->Context();
    return JS::UserCompartmentCount(cx);
}

class JSMainRuntimeTemporaryPeakReporter final : public nsIMemoryReporter
{
    ~JSMainRuntimeTemporaryPeakReporter() {}

  public:
    NS_DECL_ISUPPORTS

    NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
                              nsISupports* aData, bool aAnonymize) override
    {
        MOZ_COLLECT_REPORT(
            "js-main-runtime-temporary-peak", KIND_OTHER, UNITS_BYTES,
            JSMainRuntimeTemporaryPeakDistinguishedAmount(),
            "Peak transient data size in the main JSRuntime (the current size "
            "of which is reported as "
            "'explicit/js-non-window/runtime/temporary').");

        return NS_OK;
    }
};

NS_IMPL_ISUPPORTS(JSMainRuntimeTemporaryPeakReporter, nsIMemoryReporter)

// The REPORT* macros do an unconditional report.  The ZCREPORT* macros are for
// compartments and zones; they aggregate any entries smaller than
// SUNDRIES_THRESHOLD into the "sundries/gc-heap" and "sundries/malloc-heap"
// entries for the compartment.

#define SUNDRIES_THRESHOLD js::MemoryReportingSundriesThreshold()

#define REPORT(_path, _kind, _units, _amount, _desc) \
    handleReport->Callback(EmptyCString(), _path, \
                           nsIMemoryReporter::_kind, \
                           nsIMemoryReporter::_units, _amount, \
                           NS_LITERAL_CSTRING(_desc), data); \

#define REPORT_BYTES(_path, _kind, _amount, _desc) \
    REPORT(_path, _kind, UNITS_BYTES, _amount, _desc);

#define REPORT_GC_BYTES(_path, _amount, _desc) \
    do { \
        size_t amount = _amount;  /* evaluate _amount only once */ \
        handleReport->Callback(EmptyCString(), _path, \
                               nsIMemoryReporter::KIND_NONHEAP, \
                               nsIMemoryReporter::UNITS_BYTES, amount, \
                               NS_LITERAL_CSTRING(_desc), data); \
        gcTotal += amount; \
    } while (0)

// Report compartment/zone non-GC (KIND_HEAP) bytes.
#define ZCREPORT_BYTES(_path, _amount, _desc) \
    do { \
        /* Assign _descLiteral plus "" into a char* to prove that it's */ \
        /* actually a literal. */ \
        size_t amount = _amount;  /* evaluate _amount only once */ \
        if (amount >= SUNDRIES_THRESHOLD) { \
            handleReport->Callback(EmptyCString(), _path, \
                                   nsIMemoryReporter::KIND_HEAP, \
                                   nsIMemoryReporter::UNITS_BYTES, amount, \
                                   NS_LITERAL_CSTRING(_desc), data); \
        } else { \
            sundriesMallocHeap += amount; \
        } \
    } while (0)

// Report compartment/zone GC bytes.
#define ZCREPORT_GC_BYTES(_path, _amount, _desc) \
    do { \
        size_t amount = _amount;  /* evaluate _amount only once */ \
        if (amount >= SUNDRIES_THRESHOLD) { \
            handleReport->Callback(EmptyCString(), _path, \
                                   nsIMemoryReporter::KIND_NONHEAP, \
                                   nsIMemoryReporter::UNITS_BYTES, amount, \
                                   NS_LITERAL_CSTRING(_desc), data); \
            gcTotal += amount; \
        } else { \
            sundriesGCHeap += amount; \
        } \
    } while (0)

// Report runtime bytes.
#define RREPORT_BYTES(_path, _kind, _amount, _desc) \
    do { \
        size_t amount = _amount;  /* evaluate _amount only once */ \
        handleReport->Callback(EmptyCString(), _path, \
                               nsIMemoryReporter::_kind, \
                               nsIMemoryReporter::UNITS_BYTES, amount, \
                               NS_LITERAL_CSTRING(_desc), data); \
        rtTotal += amount; \
    } while (0)

// Report GC thing bytes.
#define MREPORT_BYTES(_path, _kind, _amount, _desc) \
    do { \
        size_t amount = _amount;  /* evaluate _amount only once */ \
        handleReport->Callback(EmptyCString(), _path, \
                               nsIMemoryReporter::_kind, \
                               nsIMemoryReporter::UNITS_BYTES, amount, \
                               NS_LITERAL_CSTRING(_desc), data); \
        gcThingTotal += amount; \
    } while (0)

MOZ_DEFINE_MALLOC_SIZE_OF(JSMallocSizeOf)

namespace xpc {

static void
ReportZoneStats(const JS::ZoneStats& zStats,
                const xpc::ZoneStatsExtras& extras,
                nsIHandleReportCallback* handleReport,
                nsISupports* data,
                bool anonymize,
                size_t* gcTotalOut = nullptr)
{
    const nsCString& pathPrefix = extras.pathPrefix;
    size_t gcTotal = 0, sundriesGCHeap = 0, sundriesMallocHeap = 0;

    MOZ_ASSERT(!gcTotalOut == zStats.isTotals);

    ZCREPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("symbols/gc-heap"),
        zStats.symbolsGCHeap,
        "Symbols.");

    ZCREPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("gc-heap-arena-admin"),
        zStats.gcHeapArenaAdmin,
        "Bookkeeping information and alignment padding within GC arenas.");

    ZCREPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("unused-gc-things"),
        zStats.unusedGCThings.totalSize(),
        "Unused GC thing cells within non-empty arenas.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("unique-id-map"),
        zStats.uniqueIdMap,
        "Address-independent cell identities.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("shape-tables"),
        zStats.shapeTables,
        "Tables storing shape information.");

    ZCREPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("lazy-scripts/gc-heap"),
        zStats.lazyScriptsGCHeap,
        "Scripts that haven't executed yet.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("lazy-scripts/malloc-heap"),
        zStats.lazyScriptsMallocHeap,
        "Lazy script tables containing closed-over bindings or inner functions.");

    ZCREPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("jit-codes-gc-heap"),
        zStats.jitCodesGCHeap,
        "References to executable code pools used by the JITs.");

    ZCREPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("object-groups/gc-heap"),
        zStats.objectGroupsGCHeap,
        "Classification and type inference information about objects.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("object-groups/malloc-heap"),
        zStats.objectGroupsMallocHeap,
        "Object group addenda.");

    ZCREPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("scopes/gc-heap"),
        zStats.scopesGCHeap,
        "Scope information for scripts.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("scopes/malloc-heap"),
        zStats.scopesMallocHeap,
        "Arrays of binding names and other binding-related data.");

    ZCREPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("regexp-shareds/gc-heap"),
        zStats.regExpSharedsGCHeap,
        "Shared compiled regexp data.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("regexp-shareds/malloc-heap"),
        zStats.regExpSharedsMallocHeap,
        "Shared compiled regexp data.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("type-pool"),
        zStats.typePool,
        "Type sets and related data.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("regexp-zone"),
        zStats.regexpZone,
        "The regexp zone and regexp data.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("jit-zone"),
        zStats.jitZone,
        "The JIT zone.");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("baseline/optimized-stubs"),
        zStats.baselineStubsOptimized,
        "The Baseline JIT's optimized IC stubs (excluding code).");

    ZCREPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("jit-cached-cfg"),
        zStats.cachedCFG,
        "The cached CFG to construct Ion code out of it.");

    size_t stringsNotableAboutMemoryGCHeap = 0;
    size_t stringsNotableAboutMemoryMallocHeap = 0;

    #define MAYBE_INLINE \
        "The characters may be inline or on the malloc heap."
    #define MAYBE_OVERALLOCATED \
        "Sometimes over-allocated to simplify string concatenation."

    for (size_t i = 0; i < zStats.notableStrings.length(); i++) {
        const JS::NotableStringInfo& info = zStats.notableStrings[i];

        MOZ_ASSERT(!zStats.isTotals);

        // We don't do notable string detection when anonymizing, because
        // there's a good chance its for crash submission, and the memory
        // required for notable string detection is high.
        MOZ_ASSERT(!anonymize);

        nsDependentCString notableString(info.buffer);

        // Viewing about:memory generates many notable strings which contain
        // "string(length=".  If we report these as notable, then we'll create
        // even more notable strings the next time we open about:memory (unless
        // there's a GC in the meantime), and so on ad infinitum.
        //
        // To avoid cluttering up about:memory like this, we stick notable
        // strings which contain "string(length=" into their own bucket.
#       define STRING_LENGTH "string(length="
        if (FindInReadable(NS_LITERAL_CSTRING(STRING_LENGTH), notableString)) {
            stringsNotableAboutMemoryGCHeap += info.gcHeapLatin1;
            stringsNotableAboutMemoryGCHeap += info.gcHeapTwoByte;
            stringsNotableAboutMemoryMallocHeap += info.mallocHeapLatin1;
            stringsNotableAboutMemoryMallocHeap += info.mallocHeapTwoByte;
            continue;
        }

        // Escape / to \ before we put notableString into the memory reporter
        // path, because we don't want any forward slashes in the string to
        // count as path separators.
        nsCString escapedString(notableString);
        escapedString.ReplaceSubstring("/", "\\");

        bool truncated = notableString.Length() < info.length;

        nsCString path = pathPrefix +
            nsPrintfCString("strings/" STRING_LENGTH "%zu, copies=%d, \"%s\"%s)/",
                            info.length, info.numCopies, escapedString.get(),
                            truncated ? " (truncated)" : "");

        if (info.gcHeapLatin1 > 0) {
            REPORT_GC_BYTES(path + NS_LITERAL_CSTRING("gc-heap/latin1"),
                info.gcHeapLatin1,
                "Latin1 strings. " MAYBE_INLINE);
        }

        if (info.gcHeapTwoByte > 0) {
            REPORT_GC_BYTES(path + NS_LITERAL_CSTRING("gc-heap/two-byte"),
                info.gcHeapTwoByte,
                "TwoByte strings. " MAYBE_INLINE);
        }

        if (info.mallocHeapLatin1 > 0) {
            REPORT_BYTES(path + NS_LITERAL_CSTRING("malloc-heap/latin1"),
                KIND_HEAP, info.mallocHeapLatin1,
                "Non-inline Latin1 string characters. " MAYBE_OVERALLOCATED);
        }

        if (info.mallocHeapTwoByte > 0) {
            REPORT_BYTES(path + NS_LITERAL_CSTRING("malloc-heap/two-byte"),
                KIND_HEAP, info.mallocHeapTwoByte,
                "Non-inline TwoByte string characters. " MAYBE_OVERALLOCATED);
        }
    }

    nsCString nonNotablePath = pathPrefix;
    nonNotablePath += (zStats.isTotals || anonymize)
                    ? NS_LITERAL_CSTRING("strings/")
                    : NS_LITERAL_CSTRING("strings/string(<non-notable strings>)/");

    if (zStats.stringInfo.gcHeapLatin1 > 0) {
        REPORT_GC_BYTES(nonNotablePath + NS_LITERAL_CSTRING("gc-heap/latin1"),
            zStats.stringInfo.gcHeapLatin1,
            "Latin1 strings. " MAYBE_INLINE);
    }

    if (zStats.stringInfo.gcHeapTwoByte > 0) {
        REPORT_GC_BYTES(nonNotablePath + NS_LITERAL_CSTRING("gc-heap/two-byte"),
            zStats.stringInfo.gcHeapTwoByte,
            "TwoByte strings. " MAYBE_INLINE);
    }

    if (zStats.stringInfo.mallocHeapLatin1 > 0) {
        REPORT_BYTES(nonNotablePath + NS_LITERAL_CSTRING("malloc-heap/latin1"),
            KIND_HEAP, zStats.stringInfo.mallocHeapLatin1,
            "Non-inline Latin1 string characters. " MAYBE_OVERALLOCATED);
    }

    if (zStats.stringInfo.mallocHeapTwoByte > 0) {
        REPORT_BYTES(nonNotablePath + NS_LITERAL_CSTRING("malloc-heap/two-byte"),
            KIND_HEAP, zStats.stringInfo.mallocHeapTwoByte,
            "Non-inline TwoByte string characters. " MAYBE_OVERALLOCATED);
    }

    if (stringsNotableAboutMemoryGCHeap > 0) {
        MOZ_ASSERT(!zStats.isTotals);
        REPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("strings/string(<about-memory>)/gc-heap"),
            stringsNotableAboutMemoryGCHeap,
            "Strings that contain the characters '" STRING_LENGTH "', which "
            "are probably from about:memory itself." MAYBE_INLINE
            " We filter them out rather than display them, because displaying "
            "them would create even more such strings every time about:memory "
            "is refreshed.");
    }

    if (stringsNotableAboutMemoryMallocHeap > 0) {
        MOZ_ASSERT(!zStats.isTotals);
        REPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("strings/string(<about-memory>)/malloc-heap"),
            KIND_HEAP, stringsNotableAboutMemoryMallocHeap,
            "Non-inline string characters of strings that contain the "
            "characters '" STRING_LENGTH "', which are probably from "
            "about:memory itself. " MAYBE_OVERALLOCATED
            " We filter them out rather than display them, because displaying "
            "them would create even more such strings every time about:memory "
            "is refreshed.");
    }

    const JS::ShapeInfo& shapeInfo = zStats.shapeInfo;
    if (shapeInfo.shapesGCHeapTree > 0) {
        REPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("shapes/gc-heap/tree"),
            shapeInfo.shapesGCHeapTree,
        "Shapes in a property tree.");
    }

    if (shapeInfo.shapesGCHeapDict > 0) {
        REPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("shapes/gc-heap/dict"),
            shapeInfo.shapesGCHeapDict,
        "Shapes in dictionary mode.");
    }

    if (shapeInfo.shapesGCHeapBase > 0) {
        REPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("shapes/gc-heap/base"),
            shapeInfo.shapesGCHeapBase,
            "Base shapes, which collate data common to many shapes.");
    }

    if (shapeInfo.shapesMallocHeapTreeTables > 0) {
        REPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("shapes/malloc-heap/tree-tables"),
            KIND_HEAP, shapeInfo.shapesMallocHeapTreeTables,
            "Property tables of shapes in a property tree.");
    }

    if (shapeInfo.shapesMallocHeapDictTables > 0) {
        REPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("shapes/malloc-heap/dict-tables"),
            KIND_HEAP, shapeInfo.shapesMallocHeapDictTables,
            "Property tables of shapes in dictionary mode.");
    }

    if (shapeInfo.shapesMallocHeapTreeKids > 0) {
        REPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("shapes/malloc-heap/tree-kids"),
            KIND_HEAP, shapeInfo.shapesMallocHeapTreeKids,
            "Kid hashes of shapes in a property tree.");
    }

    if (sundriesGCHeap > 0) {
        // We deliberately don't use ZCREPORT_GC_BYTES here.
        REPORT_GC_BYTES(pathPrefix + NS_LITERAL_CSTRING("sundries/gc-heap"),
            sundriesGCHeap,
            "The sum of all 'gc-heap' measurements that are too small to be "
            "worth showing individually.");
    }

    if (sundriesMallocHeap > 0) {
        // We deliberately don't use ZCREPORT_BYTES here.
        REPORT_BYTES(pathPrefix + NS_LITERAL_CSTRING("sundries/malloc-heap"),
            KIND_HEAP, sundriesMallocHeap,
            "The sum of all 'malloc-heap' measurements that are too small to "
            "be worth showing individually.");
    }

    if (gcTotalOut)
        *gcTotalOut += gcTotal;

#   undef STRING_LENGTH
}

static void
ReportClassStats(const ClassInfo& classInfo, const nsACString& path,
                 nsIHandleReportCallback* handleReport,
                 nsISupports* data, size_t& gcTotal)
{
    // We deliberately don't use ZCREPORT_BYTES, so that these per-class values
    // don't go into sundries.

    if (classInfo.objectsGCHeap > 0) {
        REPORT_GC_BYTES(path + NS_LITERAL_CSTRING("objects/gc-heap"),
            classInfo.objectsGCHeap,
            "Objects, including fixed slots.");
    }

    if (classInfo.objectsMallocHeapSlots > 0) {
        REPORT_BYTES(path + NS_LITERAL_CSTRING("objects/malloc-heap/slots"),
            KIND_HEAP, classInfo.objectsMallocHeapSlots,
            "Non-fixed object slots.");
    }

    if (classInfo.objectsMallocHeapElementsNormal > 0) {
        REPORT_BYTES(path + NS_LITERAL_CSTRING("objects/malloc-heap/elements/normal"),
            KIND_HEAP, classInfo.objectsMallocHeapElementsNormal,
            "Normal (non-wasm) indexed elements.");
    }

    if (classInfo.objectsMallocHeapElementsAsmJS > 0) {
        REPORT_BYTES(path + NS_LITERAL_CSTRING("objects/malloc-heap/elements/asm.js"),
            KIND_HEAP, classInfo.objectsMallocHeapElementsAsmJS,
            "asm.js array buffer elements allocated in the malloc heap.");
    }

    if (classInfo.objectsMallocHeapMisc > 0) {
        REPORT_BYTES(path + NS_LITERAL_CSTRING("objects/malloc-heap/misc"),
            KIND_HEAP, classInfo.objectsMallocHeapMisc,
            "Miscellaneous object data.");
    }

    if (classInfo.objectsNonHeapElementsNormal > 0) {
        REPORT_BYTES(path + NS_LITERAL_CSTRING("objects/non-heap/elements/normal"),
            KIND_NONHEAP, classInfo.objectsNonHeapElementsNormal,
            "Memory-mapped non-shared array buffer elements.");
    }

    if (classInfo.objectsNonHeapElementsShared > 0) {
        REPORT_BYTES(path + NS_LITERAL_CSTRING("objects/non-heap/elements/shared"),
            KIND_NONHEAP, classInfo.objectsNonHeapElementsShared,
            "Memory-mapped shared array buffer elements. These elements are "
            "shared between one or more runtimes; the reported size is divided "
            "by the buffer's refcount.");
    }

    // WebAssembly memories are always non-heap-allocated (mmap). We never put
    // these under sundries, because (a) in practice they're almost always
    // larger than the sundries threshold, and (b) we'd need a third category of
    // sundries ("non-heap"), which would be a pain.
    if (classInfo.objectsNonHeapElementsWasm > 0) {
        REPORT_BYTES(path + NS_LITERAL_CSTRING("objects/non-heap/elements/wasm"),
            KIND_NONHEAP, classInfo.objectsNonHeapElementsWasm,
            "wasm/asm.js array buffer elements allocated outside both the "
            "malloc heap and the GC heap.");
    }

    if (classInfo.objectsNonHeapCodeWasm > 0) {
        REPORT_BYTES(path + NS_LITERAL_CSTRING("objects/non-heap/code/wasm"),
            KIND_NONHEAP, classInfo.objectsNonHeapCodeWasm,
            "AOT-compiled wasm/asm.js code.");
    }

    // Although wasm guard pages aren't committed in memory they can be very
    // large and contribute greatly to vsize and so are worth reporting.
    if (classInfo.wasmGuardPages > 0) {
        REPORT_BYTES(NS_LITERAL_CSTRING("wasm-guard-pages"),
            KIND_OTHER, classInfo.wasmGuardPages,
            "Guard pages mapped after the end of wasm memories, reserved for "
            "optimization tricks, but not committed and thus never contributing"
            " to RSS, only vsize.");
    }
}

static void
ReportCompartmentStats(const JS::CompartmentStats& cStats,
                       const xpc::CompartmentStatsExtras& extras,
                       amIAddonManager* addonManager,
                       nsIHandleReportCallback* handleReport,
                       nsISupports* data, size_t* gcTotalOut = nullptr)
{
    static const nsDependentCString addonPrefix("explicit/add-ons/");

    size_t gcTotal = 0, sundriesGCHeap = 0, sundriesMallocHeap = 0;
    nsAutoCString cJSPathPrefix(extras.jsPathPrefix);
    nsAutoCString cDOMPathPrefix(extras.domPathPrefix);

    MOZ_ASSERT(!gcTotalOut == cStats.isTotals);

    // Only attempt to prefix if we got a location and the path wasn't already
    // prefixed.
    if (extras.location && addonManager &&
        cJSPathPrefix.Find(addonPrefix, false, 0, 0) != 0) {
        nsAutoCString addonId;
        bool ok;
        if (NS_SUCCEEDED(addonManager->MapURIToAddonID(extras.location,
                                                        addonId, &ok))
            && ok) {
            // Insert the add-on id as "add-ons/@id@/" after "explicit/" to
            // aggregate add-on compartments.
            static const size_t explicitLength = strlen("explicit/");
            addonId.Insert(NS_LITERAL_CSTRING("add-ons/"), 0);
            addonId += "/";
            cJSPathPrefix.Insert(addonId, explicitLength);
            cDOMPathPrefix.Insert(addonId, explicitLength);
        }
    }

    nsCString nonNotablePath = cJSPathPrefix;
    nonNotablePath += cStats.isTotals
                    ? NS_LITERAL_CSTRING("classes/")
                    : NS_LITERAL_CSTRING("classes/class(<non-notable classes>)/");

    ReportClassStats(cStats.classInfo, nonNotablePath, handleReport, data,
                     gcTotal);

    for (size_t i = 0; i < cStats.notableClasses.length(); i++) {
        MOZ_ASSERT(!cStats.isTotals);
        const JS::NotableClassInfo& classInfo = cStats.notableClasses[i];

        nsCString classPath = cJSPathPrefix +
            nsPrintfCString("classes/class(%s)/", classInfo.className_);

        ReportClassStats(classInfo, classPath, handleReport, data, gcTotal);
    }

    // Note that we use cDOMPathPrefix here.  This is because we measure orphan
    // DOM nodes in the JS reporter, but we want to report them in a "dom"
    // sub-tree rather than a "js" sub-tree.
    ZCREPORT_BYTES(cDOMPathPrefix + NS_LITERAL_CSTRING("orphan-nodes"),
        cStats.objectsPrivate,
        "Orphan DOM nodes, i.e. those that are only reachable from JavaScript "
        "objects.");

    ZCREPORT_GC_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("scripts/gc-heap"),
        cStats.scriptsGCHeap,
        "JSScript instances. There is one per user-defined function in a "
        "script, and one for the top-level code in a script.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("scripts/malloc-heap/data"),
        cStats.scriptsMallocHeapData,
        "Various variable-length tables in JSScripts.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("baseline/data"),
        cStats.baselineData,
        "The Baseline JIT's compilation data (BaselineScripts).");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("baseline/fallback-stubs"),
        cStats.baselineStubsFallback,
        "The Baseline JIT's fallback IC stubs (excluding code).");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("ion-data"),
        cStats.ionData,
        "The IonMonkey JIT's compilation data (IonScripts).");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("type-inference/type-scripts"),
        cStats.typeInferenceTypeScripts,
        "Type sets associated with scripts.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("type-inference/allocation-site-tables"),
        cStats.typeInferenceAllocationSiteTables,
        "Tables of type objects associated with allocation sites.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("type-inference/array-type-tables"),
        cStats.typeInferenceArrayTypeTables,
        "Tables of type objects associated with array literals.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("type-inference/object-type-tables"),
        cStats.typeInferenceObjectTypeTables,
        "Tables of type objects associated with object literals.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("compartment-object"),
        cStats.compartmentObject,
        "The JSCompartment object itself.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("compartment-tables"),
        cStats.compartmentTables,
        "Compartment-wide tables storing object group information and wasm instances.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("inner-views"),
        cStats.innerViewsTable,
        "The table for array buffer inner views.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("lazy-array-buffers"),
        cStats.lazyArrayBuffersTable,
        "The table for typed object lazy array buffers.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("object-metadata"),
        cStats.objectMetadataTable,
        "The table used by debugging tools for tracking object metadata");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("cross-compartment-wrapper-table"),
        cStats.crossCompartmentWrappersTable,
        "The cross-compartment wrapper table.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("saved-stacks-set"),
        cStats.savedStacksSet,
        "The saved stacks set.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("non-syntactic-lexical-scopes-table"),
        cStats.nonSyntacticLexicalScopesTable,
        "The non-syntactic lexical scopes table.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("template-literal-map"),
        cStats.templateLiteralMap,
        "The template literal registry.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("jit-compartment"),
        cStats.jitCompartment,
        "The JIT compartment.");

    ZCREPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("private-data"),
        cStats.privateData,
        "Extra data attached to the compartment by XPConnect, including "
        "its wrapped-js.");

    if (sundriesGCHeap > 0) {
        // We deliberately don't use ZCREPORT_GC_BYTES here.
        REPORT_GC_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("sundries/gc-heap"),
            sundriesGCHeap,
            "The sum of all 'gc-heap' measurements that are too small to be "
            "worth showing individually.");
    }

    if (sundriesMallocHeap > 0) {
        // We deliberately don't use ZCREPORT_BYTES here.
        REPORT_BYTES(cJSPathPrefix + NS_LITERAL_CSTRING("sundries/malloc-heap"),
            KIND_HEAP, sundriesMallocHeap,
            "The sum of all 'malloc-heap' measurements that are too small to "
            "be worth showing individually.");
    }

    if (gcTotalOut)
        *gcTotalOut += gcTotal;
}

static void
ReportScriptSourceStats(const ScriptSourceInfo& scriptSourceInfo,
                        const nsACString& path,
                        nsIHandleReportCallback* handleReport,
                        nsISupports* data, size_t& rtTotal)
{
    if (scriptSourceInfo.misc > 0) {
        RREPORT_BYTES(path + NS_LITERAL_CSTRING("misc"),
            KIND_HEAP, scriptSourceInfo.misc,
            "Miscellaneous data relating to JavaScript source code.");
    }
}

static void
ReportJSRuntimeExplicitTreeStats(const JS::RuntimeStats& rtStats,
                                 const nsACString& rtPath,
                                 amIAddonManager* addonManager,
                                 nsIHandleReportCallback* handleReport,
                                 nsISupports* data,
                                 bool anonymize,
                                 size_t* rtTotalOut)
{
    size_t gcTotal = 0;

    for (size_t i = 0; i < rtStats.zoneStatsVector.length(); i++) {
        const JS::ZoneStats& zStats = rtStats.zoneStatsVector[i];
        const xpc::ZoneStatsExtras* extras =
          static_cast<const xpc::ZoneStatsExtras*>(zStats.extra);
        ReportZoneStats(zStats, *extras, handleReport, data, anonymize,
                        &gcTotal);
    }

    for (size_t i = 0; i < rtStats.compartmentStatsVector.length(); i++) {
        const JS::CompartmentStats& cStats = rtStats.compartmentStatsVector[i];
        const xpc::CompartmentStatsExtras* extras =
            static_cast<const xpc::CompartmentStatsExtras*>(cStats.extra);

        ReportCompartmentStats(cStats, *extras, addonManager, handleReport,
                               data, &gcTotal);
    }

    // Report the rtStats.runtime numbers under "runtime/", and compute their
    // total for later.

    size_t rtTotal = 0;

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/runtime-object"),
        KIND_HEAP, rtStats.runtime.object,
        "The JSRuntime object.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/atoms-table"),
        KIND_HEAP, rtStats.runtime.atomsTable,
        "The atoms table.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/atoms-mark-bitmaps"),
        KIND_HEAP, rtStats.runtime.atomsMarkBitmaps,
        "Mark bitmaps for atoms held by each zone.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/contexts"),
        KIND_HEAP, rtStats.runtime.contexts,
        "JSContext objects and structures that belong to them.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/temporary"),
        KIND_HEAP, rtStats.runtime.temporary,
        "Transient data (mostly parse nodes) held by the JSRuntime during "
        "compilation.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/interpreter-stack"),
        KIND_HEAP, rtStats.runtime.interpreterStack,
        "JS interpreter frames.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/math-cache"),
        KIND_HEAP, rtStats.runtime.mathCache,
        "The math cache.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/shared-immutable-strings-cache"),
        KIND_HEAP, rtStats.runtime.sharedImmutableStringsCache,
        "Immutable strings (such as JS scripts' source text) shared across all JSRuntimes.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/shared-intl-data"),
        KIND_HEAP, rtStats.runtime.sharedIntlData,
        "Shared internationalization data.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/uncompressed-source-cache"),
        KIND_HEAP, rtStats.runtime.uncompressedSourceCache,
        "The uncompressed source code cache.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/script-data"),
        KIND_HEAP, rtStats.runtime.scriptData,
        "The table holding script data shared in the runtime.");

    nsCString nonNotablePath =
        rtPath + nsPrintfCString("runtime/script-sources/source(scripts=%d, <non-notable files>)/",
                                 rtStats.runtime.scriptSourceInfo.numScripts);

    ReportScriptSourceStats(rtStats.runtime.scriptSourceInfo,
                            nonNotablePath, handleReport, data, rtTotal);

    for (size_t i = 0; i < rtStats.runtime.notableScriptSources.length(); i++) {
        const JS::NotableScriptSourceInfo& scriptSourceInfo =
            rtStats.runtime.notableScriptSources[i];

        // Escape / to \ before we put the filename into the memory reporter
        // path, because we don't want any forward slashes in the string to
        // count as path separators. Consumers of memory reporters (e.g.
        // about:memory) will convert them back to / after doing path
        // splitting.
        nsCString escapedFilename;
        if (anonymize) {
            escapedFilename.AppendPrintf("<anonymized-source-%d>", int(i));
        } else {
            nsDependentCString filename(scriptSourceInfo.filename_);
            escapedFilename.Append(filename);
            escapedFilename.ReplaceSubstring("/", "\\");
        }

        nsCString notablePath = rtPath +
            nsPrintfCString("runtime/script-sources/source(scripts=%d, %s)/",
                            scriptSourceInfo.numScripts, escapedFilename.get());

        ReportScriptSourceStats(scriptSourceInfo, notablePath,
                                handleReport, data, rtTotal);
    }

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/code/ion"),
        KIND_NONHEAP, rtStats.runtime.code.ion,
        "Code generated by the IonMonkey JIT.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/code/baseline"),
        KIND_NONHEAP, rtStats.runtime.code.baseline,
        "Code generated by the Baseline JIT.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/code/regexp"),
        KIND_NONHEAP, rtStats.runtime.code.regexp,
        "Code generated by the regexp JIT.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/code/other"),
        KIND_NONHEAP, rtStats.runtime.code.other,
        "Code generated by the JITs for wrappers and trampolines.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/code/unused"),
        KIND_NONHEAP, rtStats.runtime.code.unused,
        "Memory allocated by one of the JITs to hold code, but which is "
        "currently unused.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/marker"),
        KIND_HEAP, rtStats.runtime.gc.marker,
        "The GC mark stack and gray roots.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/nursery-committed"),
        KIND_NONHEAP, rtStats.runtime.gc.nurseryCommitted,
        "Memory being used by the GC's nursery.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/nursery-malloced-buffers"),
        KIND_HEAP, rtStats.runtime.gc.nurseryMallocedBuffers,
        "Out-of-line slots and elements belonging to objects in the nursery.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/store-buffer/vals"),
        KIND_HEAP, rtStats.runtime.gc.storeBufferVals,
        "Values in the store buffer.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/store-buffer/cells"),
        KIND_HEAP, rtStats.runtime.gc.storeBufferCells,
        "Cells in the store buffer.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/store-buffer/slots"),
        KIND_HEAP, rtStats.runtime.gc.storeBufferSlots,
        "Slots in the store buffer.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/store-buffer/whole-cells"),
        KIND_HEAP, rtStats.runtime.gc.storeBufferWholeCells,
        "Whole cells in the store buffer.");

    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/store-buffer/generics"),
        KIND_HEAP, rtStats.runtime.gc.storeBufferGenerics,
        "Generic things in the store buffer.");

    if (rtTotalOut)
        *rtTotalOut = rtTotal;

    // Report GC numbers that don't belong to a compartment.

    // We don't want to report decommitted memory in "explicit", so we just
    // change the leading "explicit/" to "decommitted/".
    nsCString rtPath2(rtPath);
    rtPath2.Replace(0, strlen("explicit"), NS_LITERAL_CSTRING("decommitted"));
    REPORT_GC_BYTES(rtPath2 + NS_LITERAL_CSTRING("gc-heap/decommitted-arenas"),
        rtStats.gcHeapDecommittedArenas,
        "GC arenas in non-empty chunks that is decommitted, i.e. it takes up "
        "address space but no physical memory or swap space.");

    REPORT_GC_BYTES(rtPath + NS_LITERAL_CSTRING("gc-heap/unused-chunks"),
        rtStats.gcHeapUnusedChunks,
        "Empty GC chunks which will soon be released unless claimed for new "
        "allocations.");

    REPORT_GC_BYTES(rtPath + NS_LITERAL_CSTRING("gc-heap/unused-arenas"),
        rtStats.gcHeapUnusedArenas,
        "Empty GC arenas within non-empty chunks.");

    REPORT_GC_BYTES(rtPath + NS_LITERAL_CSTRING("gc-heap/chunk-admin"),
        rtStats.gcHeapChunkAdmin,
        "Bookkeeping information within GC chunks.");

    // gcTotal is the sum of everything we've reported for the GC heap.  It
    // should equal rtStats.gcHeapChunkTotal.
    MOZ_ASSERT(gcTotal == rtStats.gcHeapChunkTotal);
}

void
ReportJSRuntimeExplicitTreeStats(const JS::RuntimeStats& rtStats,
                                 const nsACString& rtPath,
                                 nsIHandleReportCallback* handleReport,
                                 nsISupports* data,
                                 bool anonymize,
                                 size_t* rtTotalOut)
{
    nsCOMPtr<amIAddonManager> am;
    if (XRE_IsParentProcess()) {
        // Only try to access the service from the main process.
        am = do_GetService("@mozilla.org/addons/integration;1");
    }
    ReportJSRuntimeExplicitTreeStats(rtStats, rtPath, am.get(), handleReport,
                                     data, anonymize, rtTotalOut);
}


} // namespace xpc

class JSMainRuntimeCompartmentsReporter final : public nsIMemoryReporter
{

    ~JSMainRuntimeCompartmentsReporter() {}

  public:
    NS_DECL_ISUPPORTS

    struct Data {
        int anonymizeID;
        js::Vector<nsCString, 0, js::SystemAllocPolicy> paths;
    };

    static void CompartmentCallback(JSContext* cx, void* vdata, JSCompartment* c) {
        // silently ignore OOM errors
        Data* data = static_cast<Data*>(vdata);
        nsCString path;
        GetCompartmentName(c, path, &data->anonymizeID, /* replaceSlashes = */ true);
        path.Insert(js::IsSystemCompartment(c)
                    ? NS_LITERAL_CSTRING("js-main-runtime-compartments/system/")
                    : NS_LITERAL_CSTRING("js-main-runtime-compartments/user/"),
                    0);
        mozilla::Unused << data->paths.append(path);
    }

    NS_IMETHOD CollectReports(nsIHandleReportCallback* handleReport,
                              nsISupports* data, bool anonymize) override
    {
        // First we collect the compartment paths.  Then we report them.  Doing
        // the two steps interleaved is a bad idea, because calling
        // |handleReport| from within CompartmentCallback() leads to all manner
        // of assertions.

        Data d;
        d.anonymizeID = anonymize ? 1 : 0;
        JS_IterateCompartments(XPCJSContext::Get()->Context(),
                               &d, CompartmentCallback);

        for (size_t i = 0; i < d.paths.length(); i++)
            REPORT(nsCString(d.paths[i]), KIND_OTHER, UNITS_COUNT, 1,
                "A live compartment in the main JSRuntime.");

        return NS_OK;
    }
};

NS_IMPL_ISUPPORTS(JSMainRuntimeCompartmentsReporter, nsIMemoryReporter)

MOZ_DEFINE_MALLOC_SIZE_OF(OrphanMallocSizeOf)

namespace xpc {

class OrphanReporter : public JS::ObjectPrivateVisitor
{
  public:
    explicit OrphanReporter(GetISupportsFun aGetISupports)
      : JS::ObjectPrivateVisitor(aGetISupports)
      , mState(OrphanMallocSizeOf)
    {}

    virtual size_t sizeOfIncludingThis(nsISupports* aSupports) override
    {
        size_t n = 0;
        nsCOMPtr<nsINode> node = do_QueryInterface(aSupports);
        // https://bugzilla.mozilla.org/show_bug.cgi?id=773533#c11 explains
        // that we have to skip XBL elements because they violate certain
        // assumptions.  Yuk.
        if (node && !node->IsInUncomposedDoc() &&
            !(node->IsElement() && node->AsElement()->IsInNamespace(kNameSpaceID_XBL)))
        {
            // This is an orphan node.  If we haven't already handled the
            // sub-tree that this node belongs to, measure the sub-tree's size
            // and then record its root so we don't measure it again.
            nsCOMPtr<nsINode> orphanTree = node->SubtreeRoot();
            if (orphanTree && !mState.HaveSeenPtr(orphanTree.get())) {
                n += SizeOfTreeIncludingThis(orphanTree);
            }
        }
        return n;
    }

    size_t SizeOfTreeIncludingThis(nsINode* tree)
    {
        size_t nodeSize = 0;
        nsStyleSizes sizes;
        tree->AddSizeOfIncludingThis(mState, sizes, &nodeSize);
        for (nsIContent* child = tree->GetFirstChild(); child; child = child->GetNextNode(tree))
            child->AddSizeOfIncludingThis(mState, sizes, &nodeSize);

        // We combine the node size with nsStyleSizes here. It's not ideal, but
        // it's hard to get the style structs measurements out to
        // nsWindowMemoryReporter. Also, we drop mServoData in
        // UnbindFromTree(), so in theory any non-in-tree element won't have
        // any style data to measure.
        return nodeSize + sizes.getTotalSize();
    }

  private:
    SizeOfState mState;
};

#ifdef DEBUG
static bool
StartsWithExplicit(nsACString& s)
{
    return StringBeginsWith(s, NS_LITERAL_CSTRING("explicit/"));
}
#endif

class XPCJSRuntimeStats : public JS::RuntimeStats
{
    WindowPaths* mWindowPaths;
    WindowPaths* mTopWindowPaths;
    bool mGetLocations;
    int mAnonymizeID;

  public:
    XPCJSRuntimeStats(WindowPaths* windowPaths, WindowPaths* topWindowPaths,
                      bool getLocations, bool anonymize)
      : JS::RuntimeStats(JSMallocSizeOf),
        mWindowPaths(windowPaths),
        mTopWindowPaths(topWindowPaths),
        mGetLocations(getLocations),
        mAnonymizeID(anonymize ? 1 : 0)
    {}

    ~XPCJSRuntimeStats() {
        for (size_t i = 0; i != compartmentStatsVector.length(); ++i)
            delete static_cast<xpc::CompartmentStatsExtras*>(compartmentStatsVector[i].extra);


        for (size_t i = 0; i != zoneStatsVector.length(); ++i)
            delete static_cast<xpc::ZoneStatsExtras*>(zoneStatsVector[i].extra);
    }

    virtual void initExtraZoneStats(JS::Zone* zone, JS::ZoneStats* zStats) override {
        // Get the compartment's global.
        AutoSafeJSContext cx;
        JSCompartment* comp = js::GetAnyCompartmentInZone(zone);
        xpc::ZoneStatsExtras* extras = new xpc::ZoneStatsExtras;
        extras->pathPrefix.AssignLiteral("explicit/js-non-window/zones/");
        RootedObject global(cx, JS_GetGlobalForCompartmentOrNull(cx, comp));
        if (global) {
            RefPtr<nsGlobalWindow> window;
            if (NS_SUCCEEDED(UNWRAP_OBJECT(Window, global, window))) {
                // The global is a |window| object.  Use the path prefix that
                // we should have already created for it.
                if (mTopWindowPaths->Get(window->WindowID(),
                                         &extras->pathPrefix))
                    extras->pathPrefix.AppendLiteral("/js-");
            }
        }

        extras->pathPrefix += nsPrintfCString("zone(0x%p)/", (void*)zone);

        MOZ_ASSERT(StartsWithExplicit(extras->pathPrefix));

        zStats->extra = extras;
    }

    virtual void initExtraCompartmentStats(JSCompartment* c,
                                           JS::CompartmentStats* cstats) override
    {
        xpc::CompartmentStatsExtras* extras = new xpc::CompartmentStatsExtras;
        nsCString cName;
        GetCompartmentName(c, cName, &mAnonymizeID, /* replaceSlashes = */ true);
        CompartmentPrivate* cp = CompartmentPrivate::Get(c);
        if (cp) {
            if (mGetLocations) {
                cp->GetLocationURI(CompartmentPrivate::LocationHintAddon,
                                   getter_AddRefs(extras->location));
            }
            // Note: cannot use amIAddonManager implementation at this point,
            // as it is a JS service and the JS heap is currently not idle.
            // Otherwise, we could have computed the add-on id at this point.
        }

        // Get the compartment's global.
        AutoSafeJSContext cx;
        bool needZone = true;
        RootedObject global(cx, JS_GetGlobalForCompartmentOrNull(cx, c));
        if (global) {
            RefPtr<nsGlobalWindow> window;
            if (NS_SUCCEEDED(UNWRAP_OBJECT(Window, global, window))) {
                // The global is a |window| object.  Use the path prefix that
                // we should have already created for it.
                if (mWindowPaths->Get(window->WindowID(),
                                      &extras->jsPathPrefix)) {
                    extras->domPathPrefix.Assign(extras->jsPathPrefix);
                    extras->domPathPrefix.AppendLiteral("/dom/");
                    extras->jsPathPrefix.AppendLiteral("/js-");
                    needZone = false;
                } else {
                    extras->jsPathPrefix.AssignLiteral("explicit/js-non-window/zones/");
                    extras->domPathPrefix.AssignLiteral("explicit/dom/unknown-window-global?!/");
                }
            } else {
                extras->jsPathPrefix.AssignLiteral("explicit/js-non-window/zones/");
                extras->domPathPrefix.AssignLiteral("explicit/dom/non-window-global?!/");
            }
        } else {
            extras->jsPathPrefix.AssignLiteral("explicit/js-non-window/zones/");
            extras->domPathPrefix.AssignLiteral("explicit/dom/no-global?!/");
        }

        if (needZone)
            extras->jsPathPrefix += nsPrintfCString("zone(0x%p)/", (void*)js::GetCompartmentZone(c));

        extras->jsPathPrefix += NS_LITERAL_CSTRING("compartment(") + cName + NS_LITERAL_CSTRING(")/");

        // extras->jsPathPrefix is used for almost all the compartment-specific
        // reports. At this point it has the form
        // "<something>compartment(<cname>)/".
        //
        // extras->domPathPrefix is used for DOM orphan nodes, which are
        // counted by the JS reporter but reported as part of the DOM
        // measurements. At this point it has the form "<something>/dom/" if
        // this compartment belongs to an nsGlobalWindow, and
        // "explicit/dom/<something>?!/" otherwise (in which case it shouldn't
        // be used, because non-nsGlobalWindow compartments shouldn't have
        // orphan DOM nodes).

        MOZ_ASSERT(StartsWithExplicit(extras->jsPathPrefix));
        MOZ_ASSERT(StartsWithExplicit(extras->domPathPrefix));

        cstats->extra = extras;
    }
};

void
JSReporter::CollectReports(WindowPaths* windowPaths,
                           WindowPaths* topWindowPaths,
                           nsIHandleReportCallback* handleReport,
                           nsISupports* data,
                           bool anonymize)
{
    XPCJSRuntime* xpcrt = nsXPConnect::GetRuntimeInstance();

    // In the first step we get all the stats and stash them in a local
    // data structure.  In the second step we pass all the stashed stats to
    // the callback.  Separating these steps is important because the
    // callback may be a JS function, and executing JS while getting these
    // stats seems like a bad idea.

    nsCOMPtr<amIAddonManager> addonManager;
    if (XRE_IsParentProcess()) {
        // Only try to access the service from the main process.
        addonManager = do_GetService("@mozilla.org/addons/integration;1");
    }
    bool getLocations = !!addonManager;
    XPCJSRuntimeStats rtStats(windowPaths, topWindowPaths, getLocations,
                              anonymize);
    OrphanReporter orphanReporter(XPCConvert::GetISupportsFromJSObject);
    JSContext* cx = XPCJSContext::Get()->Context();
    if (!JS::CollectRuntimeStats(cx, &rtStats, &orphanReporter,
                                 anonymize))
    {
        return;
    }

    JS::CollectTraceLoggerStateStats(&rtStats);

    size_t xpcJSRuntimeSize = xpcrt->SizeOfIncludingThis(JSMallocSizeOf);

    size_t wrappedJSSize = xpcrt->GetMultiCompartmentWrappedJSMap()->SizeOfWrappedJS(JSMallocSizeOf);

    XPCWrappedNativeScope::ScopeSizeInfo sizeInfo(JSMallocSizeOf);
    XPCWrappedNativeScope::AddSizeOfAllScopesIncludingThis(&sizeInfo);

    mozJSComponentLoader* loader = mozJSComponentLoader::Get();
    size_t jsComponentLoaderSize = loader ? loader->SizeOfIncludingThis(JSMallocSizeOf) : 0;

    // This is the second step (see above).  First we report stuff in the
    // "explicit" tree, then we report other stuff.

    size_t rtTotal = 0;
    xpc::ReportJSRuntimeExplicitTreeStats(rtStats,
                                          NS_LITERAL_CSTRING("explicit/js-non-window/"),
                                          addonManager, handleReport, data,
                                          anonymize, &rtTotal);

    // Report the sums of the compartment numbers.
    xpc::CompartmentStatsExtras cExtrasTotal;
    cExtrasTotal.jsPathPrefix.AssignLiteral("js-main-runtime/compartments/");
    cExtrasTotal.domPathPrefix.AssignLiteral("window-objects/dom/");
    ReportCompartmentStats(rtStats.cTotals, cExtrasTotal, addonManager,
                           handleReport, data);

    xpc::ZoneStatsExtras zExtrasTotal;
    zExtrasTotal.pathPrefix.AssignLiteral("js-main-runtime/zones/");
    ReportZoneStats(rtStats.zTotals, zExtrasTotal, handleReport, data,
                    anonymize);

    // Report the sum of the runtime/ numbers.
    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime/runtime"),
        KIND_OTHER, rtTotal,
        "The sum of all measurements under 'explicit/js-non-window/runtime/'.");

    // Report the numbers for memory used by tracelogger.
    REPORT_BYTES(NS_LITERAL_CSTRING("tracelogger"),
        KIND_OTHER, rtStats.runtime.tracelogger,
        "The memory used for the tracelogger, including the graph and events.");

    // Report the numbers for memory outside of compartments.

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime/gc-heap/unused-chunks"),
        KIND_OTHER, rtStats.gcHeapUnusedChunks,
        "The same as 'explicit/js-non-window/gc-heap/unused-chunks'.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime/gc-heap/unused-arenas"),
        KIND_OTHER, rtStats.gcHeapUnusedArenas,
        "The same as 'explicit/js-non-window/gc-heap/unused-arenas'.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime/gc-heap/chunk-admin"),
        KIND_OTHER, rtStats.gcHeapChunkAdmin,
        "The same as 'explicit/js-non-window/gc-heap/chunk-admin'.");

    // Report a breakdown of the committed GC space.

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/chunks"),
        KIND_OTHER, rtStats.gcHeapUnusedChunks,
        "The same as 'explicit/js-non-window/gc-heap/unused-chunks'.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/arenas"),
        KIND_OTHER, rtStats.gcHeapUnusedArenas,
        "The same as 'explicit/js-non-window/gc-heap/unused-arenas'.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/objects"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.object,
        "Unused object cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/strings"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.string,
        "Unused string cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/symbols"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.symbol,
        "Unused symbol cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/shapes"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.shape,
        "Unused shape cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/base-shapes"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.baseShape,
        "Unused base shape cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/object-groups"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.objectGroup,
        "Unused object group cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/scopes"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.scope,
        "Unused scope cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/scripts"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.script,
        "Unused script cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/lazy-scripts"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.lazyScript,
        "Unused lazy script cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/jitcode"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.jitcode,
        "Unused jitcode cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/unused/gc-things/regexp-shareds"),
        KIND_OTHER, rtStats.zTotals.unusedGCThings.regExpShared,
        "Unused regexpshared cells within non-empty arenas.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/chunk-admin"),
        KIND_OTHER, rtStats.gcHeapChunkAdmin,
        "The same as 'explicit/js-non-window/gc-heap/chunk-admin'.");

    REPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/arena-admin"),
        KIND_OTHER, rtStats.zTotals.gcHeapArenaAdmin,
        "The same as 'js-main-runtime/zones/gc-heap-arena-admin'.");

    size_t gcThingTotal = 0;

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/objects"),
        KIND_OTHER, rtStats.cTotals.classInfo.objectsGCHeap,
        "Used object cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/strings"),
        KIND_OTHER, rtStats.zTotals.stringInfo.sizeOfLiveGCThings(),
        "Used string cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/symbols"),
        KIND_OTHER, rtStats.zTotals.symbolsGCHeap,
        "Used symbol cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/shapes"),
        KIND_OTHER,
        rtStats.zTotals.shapeInfo.shapesGCHeapTree + rtStats.zTotals.shapeInfo.shapesGCHeapDict,
        "Used shape cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/base-shapes"),
        KIND_OTHER, rtStats.zTotals.shapeInfo.shapesGCHeapBase,
        "Used base shape cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/object-groups"),
        KIND_OTHER, rtStats.zTotals.objectGroupsGCHeap,
        "Used object group cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/scopes"),
        KIND_OTHER, rtStats.zTotals.scopesGCHeap,
        "Used scope cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/scripts"),
        KIND_OTHER, rtStats.cTotals.scriptsGCHeap,
        "Used script cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/lazy-scripts"),
        KIND_OTHER, rtStats.zTotals.lazyScriptsGCHeap,
        "Used lazy script cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/jitcode"),
        KIND_OTHER, rtStats.zTotals.jitCodesGCHeap,
        "Used jitcode cells.");

    MREPORT_BYTES(NS_LITERAL_CSTRING("js-main-runtime-gc-heap-committed/used/gc-things/regexp-shareds"),
        KIND_OTHER, rtStats.zTotals.regExpSharedsGCHeap,
        "Used regexpshared cells.");

    MOZ_ASSERT(gcThingTotal == rtStats.gcHeapGCThings);

    // Report xpconnect.

    REPORT_BYTES(NS_LITERAL_CSTRING("explicit/xpconnect/runtime"),
        KIND_HEAP, xpcJSRuntimeSize,
        "The XPConnect runtime.");

    REPORT_BYTES(NS_LITERAL_CSTRING("explicit/xpconnect/wrappedjs"),
        KIND_HEAP, wrappedJSSize,
        "Wrappers used to implement XPIDL interfaces with JS.");

    REPORT_BYTES(NS_LITERAL_CSTRING("explicit/xpconnect/scopes"),
        KIND_HEAP, sizeInfo.mScopeAndMapSize,
        "XPConnect scopes.");

    REPORT_BYTES(NS_LITERAL_CSTRING("explicit/xpconnect/proto-iface-cache"),
        KIND_HEAP, sizeInfo.mProtoAndIfaceCacheSize,
        "Prototype and interface binding caches.");

    REPORT_BYTES(NS_LITERAL_CSTRING("explicit/xpconnect/js-component-loader"),
        KIND_HEAP, jsComponentLoaderSize,
        "XPConnect's JS component loader.");
}

static nsresult
JSSizeOfTab(JSObject* objArg, size_t* jsObjectsSize, size_t* jsStringsSize,
            size_t* jsPrivateSize, size_t* jsOtherSize)
{
    JSContext* cx = XPCJSContext::Get()->Context();
    JS::RootedObject obj(cx, objArg);

    TabSizes sizes;
    OrphanReporter orphanReporter(XPCConvert::GetISupportsFromJSObject);
    NS_ENSURE_TRUE(JS::AddSizeOfTab(cx, obj, moz_malloc_size_of,
                                    &orphanReporter, &sizes),
                   NS_ERROR_OUT_OF_MEMORY);

    *jsObjectsSize = sizes.objects;
    *jsStringsSize = sizes.strings;
    *jsPrivateSize = sizes.private_;
    *jsOtherSize   = sizes.other;
    return NS_OK;
}

} // namespace xpc

static void
AccumulateTelemetryCallback(int id, uint32_t sample, const char* key)
{
    switch (id) {
      case JS_TELEMETRY_GC_REASON:
        Telemetry::Accumulate(Telemetry::GC_REASON_2, sample);
        break;
      case JS_TELEMETRY_GC_IS_ZONE_GC:
        Telemetry::Accumulate(Telemetry::GC_IS_COMPARTMENTAL, sample);
        break;
      case JS_TELEMETRY_GC_MS:
        Telemetry::Accumulate(Telemetry::GC_MS, sample);
        break;
      case JS_TELEMETRY_GC_BUDGET_MS:
        Telemetry::Accumulate(Telemetry::GC_BUDGET_MS, sample);
        break;
      case JS_TELEMETRY_GC_BUDGET_OVERRUN:
        Telemetry::Accumulate(Telemetry::GC_BUDGET_OVERRUN, sample);
        break;
      case JS_TELEMETRY_GC_ANIMATION_MS:
        Telemetry::Accumulate(Telemetry::GC_ANIMATION_MS, sample);
        break;
      case JS_TELEMETRY_GC_MAX_PAUSE_MS:
        Telemetry::Accumulate(Telemetry::GC_MAX_PAUSE_MS, sample);
        break;
      case JS_TELEMETRY_GC_MAX_PAUSE_MS_2:
        Telemetry::Accumulate(Telemetry::GC_MAX_PAUSE_MS_2, sample);
        break;
      case JS_TELEMETRY_GC_MARK_MS:
        Telemetry::Accumulate(Telemetry::GC_MARK_MS, sample);
        break;
      case JS_TELEMETRY_GC_SWEEP_MS:
        Telemetry::Accumulate(Telemetry::GC_SWEEP_MS, sample);
        break;
      case JS_TELEMETRY_GC_COMPACT_MS:
        Telemetry::Accumulate(Telemetry::GC_COMPACT_MS, sample);
        break;
      case JS_TELEMETRY_GC_MARK_ROOTS_MS:
        Telemetry::Accumulate(Telemetry::GC_MARK_ROOTS_MS, sample);
        break;
      case JS_TELEMETRY_GC_MARK_GRAY_MS:
        Telemetry::Accumulate(Telemetry::GC_MARK_GRAY_MS, sample);
        break;
      case JS_TELEMETRY_GC_SLICE_MS:
        Telemetry::Accumulate(Telemetry::GC_SLICE_MS, sample);
        break;
      case JS_TELEMETRY_GC_SLOW_PHASE:
        Telemetry::Accumulate(Telemetry::GC_SLOW_PHASE, sample);
        break;
      case JS_TELEMETRY_GC_SLOW_TASK:
        Telemetry::Accumulate(Telemetry::GC_SLOW_TASK, sample);
        break;
      case JS_TELEMETRY_GC_MMU_50:
        Telemetry::Accumulate(Telemetry::GC_MMU_50, sample);
        break;
      case JS_TELEMETRY_GC_RESET:
        Telemetry::Accumulate(Telemetry::GC_RESET, sample);
        break;
      case JS_TELEMETRY_GC_RESET_REASON:
        Telemetry::Accumulate(Telemetry::GC_RESET_REASON, sample);
        break;
      case JS_TELEMETRY_GC_INCREMENTAL_DISABLED:
        Telemetry::Accumulate(Telemetry::GC_INCREMENTAL_DISABLED, sample);
        break;
      case JS_TELEMETRY_GC_NON_INCREMENTAL:
        Telemetry::Accumulate(Telemetry::GC_NON_INCREMENTAL, sample);
        break;
      case JS_TELEMETRY_GC_NON_INCREMENTAL_REASON:
        Telemetry::Accumulate(Telemetry::GC_NON_INCREMENTAL_REASON, sample);
        break;
      case JS_TELEMETRY_GC_SCC_SWEEP_TOTAL_MS:
        Telemetry::Accumulate(Telemetry::GC_SCC_SWEEP_TOTAL_MS, sample);
        break;
      case JS_TELEMETRY_GC_SCC_SWEEP_MAX_PAUSE_MS:
        Telemetry::Accumulate(Telemetry::GC_SCC_SWEEP_MAX_PAUSE_MS, sample);
        break;
      case JS_TELEMETRY_GC_MINOR_REASON:
        Telemetry::Accumulate(Telemetry::GC_MINOR_REASON, sample);
        break;
      case JS_TELEMETRY_GC_MINOR_REASON_LONG:
        Telemetry::Accumulate(Telemetry::GC_MINOR_REASON_LONG, sample);
        break;
      case JS_TELEMETRY_GC_MINOR_US:
        Telemetry::Accumulate(Telemetry::GC_MINOR_US, sample);
        break;
      case JS_TELEMETRY_GC_NURSERY_BYTES:
        Telemetry::Accumulate(Telemetry::GC_NURSERY_BYTES, sample);
        break;
      case JS_TELEMETRY_GC_PRETENURE_COUNT:
        Telemetry::Accumulate(Telemetry::GC_PRETENURE_COUNT, sample);
        break;
      case JS_TELEMETRY_DEPRECATED_LANGUAGE_EXTENSIONS_IN_CONTENT:
        Telemetry::Accumulate(Telemetry::JS_DEPRECATED_LANGUAGE_EXTENSIONS_IN_CONTENT, sample);
        break;
      case JS_TELEMETRY_DEPRECATED_LANGUAGE_EXTENSIONS_IN_ADDONS:
        Telemetry::Accumulate(Telemetry::JS_DEPRECATED_LANGUAGE_EXTENSIONS_IN_ADDONS, sample);
        break;
      case JS_TELEMETRY_ADDON_EXCEPTIONS:
        Telemetry::Accumulate(Telemetry::JS_TELEMETRY_ADDON_EXCEPTIONS, nsDependentCString(key), sample);
        break;
      case JS_TELEMETRY_AOT_USAGE:
        Telemetry::Accumulate(Telemetry::JS_AOT_USAGE, sample);
        break;
      case JS_TELEMETRY_PRIVILEGED_PARSER_COMPILE_LAZY_AFTER_MS:
        Telemetry::Accumulate(Telemetry::JS_PRIVILEGED_PARSER_COMPILE_LAZY_AFTER_MS, sample);
        break;
      case JS_TELEMETRY_WEB_PARSER_COMPILE_LAZY_AFTER_MS:
        Telemetry::Accumulate(Telemetry::JS_WEB_PARSER_COMPILE_LAZY_AFTER_MS, sample);
        break;
      default:
        MOZ_ASSERT_UNREACHABLE("Unexpected JS_TELEMETRY id");
    }
}

static void
CompartmentNameCallback(JSContext* cx, JSCompartment* comp,
                        char* buf, size_t bufsize)
{
    nsCString name;
    // This is called via the JSAPI and isn't involved in memory reporting, so
    // we don't need to anonymize compartment names.
    int anonymizeID = 0;
    GetCompartmentName(comp, name, &anonymizeID, /* replaceSlashes = */ false);
    if (name.Length() >= bufsize)
        name.Truncate(bufsize - 1);
    memcpy(buf, name.get(), name.Length() + 1);
}

static void
GetRealmName(JSContext* cx, JS::Handle<JS::Realm*> realm, char* buf, size_t bufsize)
{
    JSCompartment* comp = JS::GetCompartmentForRealm(realm);
    CompartmentNameCallback(cx, comp, buf, bufsize);
}

static bool
PreserveWrapper(JSContext* cx, JSObject* obj)
{
    MOZ_ASSERT(cx);
    MOZ_ASSERT(obj);
    MOZ_ASSERT(IS_WN_REFLECTOR(obj) || mozilla::dom::IsDOMObject(obj));

    return mozilla::dom::IsDOMObject(obj) && mozilla::dom::TryPreserveWrapper(obj);
}

static nsresult
ReadSourceFromFilename(JSContext* cx, const char* filename, char16_t** src, size_t* len)
{
    nsresult rv;

    // mozJSSubScriptLoader prefixes the filenames of the scripts it loads with
    // the filename of its caller. Axe that if present.
    const char* arrow;
    while ((arrow = strstr(filename, " -> ")))
        filename = arrow + strlen(" -> ");

    // Get the URI.
    nsCOMPtr<nsIURI> uri;
    rv = NS_NewURI(getter_AddRefs(uri), filename);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIChannel> scriptChannel;
    rv = NS_NewChannel(getter_AddRefs(scriptChannel),
                       uri,
                       nsContentUtils::GetSystemPrincipal(),
                       nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_IS_NULL,
                       nsIContentPolicy::TYPE_OTHER);
    NS_ENSURE_SUCCESS(rv, rv);

    // Only allow local reading.
    nsCOMPtr<nsIURI> actualUri;
    rv = scriptChannel->GetURI(getter_AddRefs(actualUri));
    NS_ENSURE_SUCCESS(rv, rv);
    nsCString scheme;
    rv = actualUri->GetScheme(scheme);
    NS_ENSURE_SUCCESS(rv, rv);
    if (!scheme.EqualsLiteral("file") && !scheme.EqualsLiteral("jar"))
        return NS_OK;

    // Explicitly set the content type so that we don't load the
    // exthandler to guess it.
    scriptChannel->SetContentType(NS_LITERAL_CSTRING("text/plain"));

    nsCOMPtr<nsIInputStream> scriptStream;
    rv = scriptChannel->Open2(getter_AddRefs(scriptStream));
    NS_ENSURE_SUCCESS(rv, rv);

    uint64_t rawLen;
    rv = scriptStream->Available(&rawLen);
    NS_ENSURE_SUCCESS(rv, rv);
    if (!rawLen)
        return NS_ERROR_FAILURE;

    // Technically, this should be SIZE_MAX, but we don't run on machines
    // where that would be less than UINT32_MAX, and the latter is already
    // well beyond a reasonable limit.
    if (rawLen > UINT32_MAX)
        return NS_ERROR_FILE_TOO_BIG;

    // Allocate an internal buf the size of the file.
    auto buf = MakeUniqueFallible<unsigned char[]>(rawLen);
    if (!buf)
        return NS_ERROR_OUT_OF_MEMORY;

    unsigned char* ptr = buf.get();
    unsigned char* end = ptr + rawLen;
    while (ptr < end) {
        uint32_t bytesRead;
        rv = scriptStream->Read(reinterpret_cast<char*>(ptr), end - ptr, &bytesRead);
        if (NS_FAILED(rv))
            return rv;
        MOZ_ASSERT(bytesRead > 0, "stream promised more bytes before EOF");
        ptr += bytesRead;
    }

    rv = ScriptLoader::ConvertToUTF16(scriptChannel, buf.get(), rawLen,
                                      EmptyString(), nullptr, *src, *len);
    NS_ENSURE_SUCCESS(rv, rv);

    if (!*src)
        return NS_ERROR_FAILURE;

    // Historically this method used JS_malloc() which updates the GC memory
    // accounting.  Since ConvertToUTF16() now uses js_malloc() instead we
    // update the accounting manually after the fact.
    JS_updateMallocCounter(cx, *len);

    return NS_OK;
}

// The JS engine calls this object's 'load' member function when it needs
// the source for a chrome JS function. See the comment in the XPCJSRuntime
// constructor.
class XPCJSSourceHook: public js::SourceHook {
    bool load(JSContext* cx, const char* filename, char16_t** src, size_t* length) {
        *src = nullptr;
        *length = 0;

        if (!nsContentUtils::IsSystemCaller(cx))
            return true;

        if (!filename)
            return true;

        nsresult rv = ReadSourceFromFilename(cx, filename, src, length);
        if (NS_FAILED(rv)) {
            xpc::Throw(cx, rv);
            return false;
        }

        return true;
    }
};

static const JSWrapObjectCallbacks WrapObjectCallbacks = {
    xpc::WrapperFactory::Rewrap,
    xpc::WrapperFactory::PrepareForWrapping
};

XPCJSRuntime::XPCJSRuntime(JSContext* aCx)
 : CycleCollectedJSRuntime(aCx),
   mWrappedJSMap(JSObject2WrappedJSMap::newMap(XPC_JS_MAP_LENGTH)),
   mWrappedJSClassMap(IID2WrappedJSClassMap::newMap(XPC_JS_CLASS_MAP_LENGTH)),
   mIID2NativeInterfaceMap(IID2NativeInterfaceMap::newMap(XPC_NATIVE_INTERFACE_MAP_LENGTH)),
   mClassInfo2NativeSetMap(ClassInfo2NativeSetMap::newMap(XPC_NATIVE_SET_MAP_LENGTH)),
   mNativeSetMap(NativeSetMap::newMap(XPC_NATIVE_SET_MAP_LENGTH)),
   mThisTranslatorMap(IID2ThisTranslatorMap::newMap(XPC_THIS_TRANSLATOR_MAP_LENGTH)),
   mDyingWrappedNativeProtoMap(XPCWrappedNativeProtoMap::newMap(XPC_DYING_NATIVE_PROTO_MAP_LENGTH)),
   mGCIsRunning(false),
   mNativesToReleaseArray(),
   mDoingFinalization(false),
   mVariantRoots(nullptr),
   mWrappedJSRoots(nullptr),
   mAsyncSnowWhiteFreer(new AsyncFreeSnowWhite())
{
    MOZ_COUNT_CTOR_INHERITED(XPCJSRuntime, CycleCollectedJSRuntime);
}

/* static */
XPCJSRuntime*
XPCJSRuntime::Get()
{
    return nsXPConnect::GetRuntimeInstance();
}

void
XPCJSRuntime::Initialize(JSContext* cx)
{
    mUnprivilegedJunkScope.init(cx, nullptr);
    mPrivilegedJunkScope.init(cx, nullptr);
    mCompilationScope.init(cx, nullptr);

    // these jsids filled in later when we have a JSContext to work with.
    mStrIDs[0] = JSID_VOID;

    // Unconstrain the runtime's threshold on nominal heap size, to avoid
    // triggering GC too often if operating continuously near an arbitrary
    // finite threshold (0xffffffff is infinity for uint32_t parameters).
    // This leaves the maximum-JS_malloc-bytes threshold still in effect
    // to cause period, and we hope hygienic, last-ditch GCs from within
    // the GC's allocator.
    JS_SetGCParameter(cx, JSGC_MAX_BYTES, 0xffffffff);

    JS_SetDestroyCompartmentCallback(cx, CompartmentDestroyedCallback);
    JS_SetSizeOfIncludingThisCompartmentCallback(cx, CompartmentSizeOfIncludingThisCallback);
    JS_SetCompartmentNameCallback(cx, CompartmentNameCallback);
    JS::SetRealmNameCallback(cx, GetRealmName);
    mPrevGCSliceCallback = JS::SetGCSliceCallback(cx, GCSliceCallback);
    mPrevDoCycleCollectionCallback = JS::SetDoCycleCollectionCallback(cx,
            DoCycleCollectionCallback);
    JS_AddFinalizeCallback(cx, FinalizeCallback, nullptr);
    JS_AddWeakPointerZonesCallback(cx, WeakPointerZonesCallback, this);
    JS_AddWeakPointerCompartmentCallback(cx, WeakPointerCompartmentCallback, this);
    JS_SetWrapObjectCallbacks(cx, &WrapObjectCallbacks);
    js::SetPreserveWrapperCallback(cx, PreserveWrapper);
    JS_SetAccumulateTelemetryCallback(cx, AccumulateTelemetryCallback);
    js::SetWindowProxyClass(cx, &OuterWindowProxyClass);
    js::SetXrayJitInfo(&gXrayJitInfo);
    JS::SetProcessLargeAllocationFailureCallback(OnLargeAllocationFailureCallback);

    // The JS engine needs to keep the source code around in order to implement
    // Function.prototype.toSource(). It'd be nice to not have to do this for
    // chrome code and simply stub out requests for source on it. Life is not so
    // easy, unfortunately. Nobody relies on chrome toSource() working in core
    // browser code, but chrome tests use it. The worst offenders are addons,
    // which like to monkeypatch chrome functions by calling toSource() on them
    // and using regular expressions to modify them. We avoid keeping most browser
    // JS source code in memory by setting LAZY_SOURCE on JS::CompileOptions when
    // compiling some chrome code. This causes the JS engine not save the source
    // code in memory. When the JS engine is asked to provide the source for a
    // function compiled with LAZY_SOURCE, it calls SourceHook to load it.
    ///
    // Note we do have to retain the source code in memory for scripts compiled in
    // isRunOnce mode and compiled function bodies (from
    // JS::CompileFunction). In practice, this means content scripts and event
    // handlers.
    mozilla::UniquePtr<XPCJSSourceHook> hook(new XPCJSSourceHook);
    js::SetSourceHook(cx, Move(hook));

    // Register memory reporters and distinguished amount functions.
    RegisterStrongMemoryReporter(new JSMainRuntimeCompartmentsReporter());
    RegisterStrongMemoryReporter(new JSMainRuntimeTemporaryPeakReporter());
    RegisterJSMainRuntimeGCHeapDistinguishedAmount(JSMainRuntimeGCHeapDistinguishedAmount);
    RegisterJSMainRuntimeTemporaryPeakDistinguishedAmount(JSMainRuntimeTemporaryPeakDistinguishedAmount);
    RegisterJSMainRuntimeCompartmentsSystemDistinguishedAmount(JSMainRuntimeCompartmentsSystemDistinguishedAmount);
    RegisterJSMainRuntimeCompartmentsUserDistinguishedAmount(JSMainRuntimeCompartmentsUserDistinguishedAmount);
    mozilla::RegisterJSSizeOfTab(JSSizeOfTab);
}

bool
XPCJSRuntime::InitializeStrings(JSContext* cx)
{
    JSAutoRequest ar(cx);

    // if it is our first context then we need to generate our string ids
    if (JSID_IS_VOID(mStrIDs[0])) {
        RootedString str(cx);
        for (unsigned i = 0; i < XPCJSContext::IDX_TOTAL_COUNT; i++) {
            str = JS_AtomizeAndPinString(cx, mStrings[i]);
            if (!str) {
                mStrIDs[0] = JSID_VOID;
                return false;
            }
            mStrIDs[i] = INTERNED_STRING_TO_JSID(cx, str);
            mStrJSVals[i].setString(str);
        }

        if (!mozilla::dom::DefineStaticJSVals(cx)) {
            return false;
        }
    }

    return true;
}

bool
XPCJSRuntime::DescribeCustomObjects(JSObject* obj, const js::Class* clasp,
                                    char (&name)[72]) const
{

    if (!IS_PROTO_CLASS(clasp)) {
        return false;
    }

    XPCWrappedNativeProto* p =
        static_cast<XPCWrappedNativeProto*>(xpc_GetJSPrivate(obj));
    nsCOMPtr<nsIXPCScriptable> scr = p->GetScriptable();
    if (!scr) {
        return false;
    }

    SprintfLiteral(name, "JS Object (%s - %s)",
                   clasp->name, scr->GetJSClass()->name);
    return true;
}

bool
XPCJSRuntime::NoteCustomGCThingXPCOMChildren(const js::Class* clasp, JSObject* obj,
                                             nsCycleCollectionTraversalCallback& cb) const
{
    if (clasp != &XPC_WN_Tearoff_JSClass) {
        return false;
    }

    // A tearoff holds a strong reference to its native object
    // (see XPCWrappedNative::FlatJSObjectFinalized). Its XPCWrappedNative
    // will be held alive through the parent of the JSObject of the tearoff.
    XPCWrappedNativeTearOff* to =
        static_cast<XPCWrappedNativeTearOff*>(xpc_GetJSPrivate(obj));
    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "xpc_GetJSPrivate(obj)->mNative");
    cb.NoteXPCOMChild(to->GetNative());
    return true;
}

/***************************************************************************/

void
XPCJSRuntime::DebugDump(int16_t depth)
{
#ifdef DEBUG
    depth--;
    XPC_LOG_ALWAYS(("XPCJSRuntime @ %p", this));
        XPC_LOG_INDENT();

        XPC_LOG_ALWAYS(("mWrappedJSClassMap @ %p with %d wrapperclasses(s)",
                        mWrappedJSClassMap, mWrappedJSClassMap->Count()));
        // iterate wrappersclasses...
        if (depth && mWrappedJSClassMap->Count()) {
            XPC_LOG_INDENT();
            for (auto i = mWrappedJSClassMap->Iter(); !i.Done(); i.Next()) {
                auto entry = static_cast<IID2WrappedJSClassMap::Entry*>(i.Get());
                entry->value->DebugDump(depth);
            }
            XPC_LOG_OUTDENT();
        }

        // iterate wrappers...
        XPC_LOG_ALWAYS(("mWrappedJSMap @ %p with %d wrappers(s)",
                        mWrappedJSMap, mWrappedJSMap->Count()));
        if (depth && mWrappedJSMap->Count()) {
            XPC_LOG_INDENT();
            mWrappedJSMap->Dump(depth);
            XPC_LOG_OUTDENT();
        }

        XPC_LOG_ALWAYS(("mIID2NativeInterfaceMap @ %p with %d interface(s)",
                        mIID2NativeInterfaceMap,
                        mIID2NativeInterfaceMap->Count()));

        XPC_LOG_ALWAYS(("mClassInfo2NativeSetMap @ %p with %d sets(s)",
                        mClassInfo2NativeSetMap,
                        mClassInfo2NativeSetMap->Count()));

        XPC_LOG_ALWAYS(("mThisTranslatorMap @ %p with %d translator(s)",
                        mThisTranslatorMap, mThisTranslatorMap->Count()));

        XPC_LOG_ALWAYS(("mNativeSetMap @ %p with %d sets(s)",
                        mNativeSetMap, mNativeSetMap->Count()));

        // iterate sets...
        if (depth && mNativeSetMap->Count()) {
            XPC_LOG_INDENT();
            for (auto i = mNativeSetMap->Iter(); !i.Done(); i.Next()) {
                auto entry = static_cast<NativeSetMap::Entry*>(i.Get());
                entry->key_value->DebugDump(depth);
            }
            XPC_LOG_OUTDENT();
        }

        XPC_LOG_OUTDENT();
#endif
}

/***************************************************************************/

void
XPCRootSetElem::AddToRootSet(XPCRootSetElem** listHead)
{
    MOZ_ASSERT(!mSelfp, "Must be not linked");

    mSelfp = listHead;
    mNext = *listHead;
    if (mNext) {
        MOZ_ASSERT(mNext->mSelfp == listHead, "Must be list start");
        mNext->mSelfp = &mNext;
    }
    *listHead = this;
}

void
XPCRootSetElem::RemoveFromRootSet()
{
    JS::NotifyGCRootsRemoved(XPCJSContext::Get()->Context());

    MOZ_ASSERT(mSelfp, "Must be linked");

    MOZ_ASSERT(*mSelfp == this, "Link invariant");
    *mSelfp = mNext;
    if (mNext)
        mNext->mSelfp = mSelfp;
#ifdef DEBUG
    mSelfp = nullptr;
    mNext = nullptr;
#endif
}

void
XPCJSRuntime::AddGCCallback(xpcGCCallback cb)
{
    MOZ_ASSERT(cb, "null callback");
    extraGCCallbacks.AppendElement(cb);
}

void
XPCJSRuntime::RemoveGCCallback(xpcGCCallback cb)
{
    MOZ_ASSERT(cb, "null callback");
    bool found = extraGCCallbacks.RemoveElement(cb);
    if (!found) {
        NS_ERROR("Removing a callback which was never added.");
    }
}

void
XPCJSRuntime::InitSingletonScopes()
{
    // This all happens very early, so we don't bother with cx pushing.
    JSContext* cx = XPCJSContext::Get()->Context();
    JSAutoRequest ar(cx);
    RootedValue v(cx);
    nsresult rv;

    // Create the Unprivileged Junk Scope.
    SandboxOptions unprivilegedJunkScopeOptions;
    unprivilegedJunkScopeOptions.sandboxName.AssignLiteral("XPConnect Junk Compartment");
    unprivilegedJunkScopeOptions.invisibleToDebugger = true;
    rv = CreateSandboxObject(cx, &v, nullptr, unprivilegedJunkScopeOptions);
    MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
    mUnprivilegedJunkScope = js::UncheckedUnwrap(&v.toObject());

    // Create the Privileged Junk Scope.
    SandboxOptions privilegedJunkScopeOptions;
    privilegedJunkScopeOptions.sandboxName.AssignLiteral("XPConnect Privileged Junk Compartment");
    privilegedJunkScopeOptions.invisibleToDebugger = true;
    privilegedJunkScopeOptions.wantComponents = false;
    rv = CreateSandboxObject(cx, &v, nsXPConnect::SystemPrincipal(), privilegedJunkScopeOptions);
    MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
    mPrivilegedJunkScope = js::UncheckedUnwrap(&v.toObject());

    // Create the Compilation Scope.
    SandboxOptions compilationScopeOptions;
    compilationScopeOptions.sandboxName.AssignLiteral("XPConnect Compilation Compartment");
    compilationScopeOptions.invisibleToDebugger = true;
    compilationScopeOptions.discardSource = ShouldDiscardSystemSource();
    rv = CreateSandboxObject(cx, &v, /* principal = */ nullptr, compilationScopeOptions);
    MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
    mCompilationScope = js::UncheckedUnwrap(&v.toObject());
}

void
XPCJSRuntime::DeleteSingletonScopes()
{
    mUnprivilegedJunkScope = nullptr;
    mPrivilegedJunkScope = nullptr;
    mCompilationScope = nullptr;
}