/* -*- 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/. */

#include "vm/Debugger-inl.h"

#include "mozilla/DebugOnly.h"
#include "mozilla/ScopeExit.h"

#include "jscntxt.h"
#include "jscompartment.h"
#include "jsfriendapi.h"
#include "jshashutil.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jswrapper.h"

#include "frontend/BytecodeCompiler.h"
#include "gc/Marking.h"
#include "jit/BaselineDebugModeOSR.h"
#include "jit/BaselineJIT.h"
#include "jit/JSONSpewer.h"
#include "jit/MIRGraph.h"
#include "js/GCAPI.h"
#include "js/UbiNodeTraverse.h"
#include "js/Vector.h"
#include "vm/ArgumentsObject.h"
#include "vm/DebuggerMemory.h"
#include "vm/SPSProfiler.h"
#include "vm/TraceLogging.h"
#include "vm/WrapperObject.h"

#include "jsgcinlines.h"
#include "jsobjinlines.h"
#include "jsopcodeinlines.h"
#include "jsscriptinlines.h"

#include "vm/NativeObject-inl.h"
#include "vm/Stack-inl.h"

using namespace js;

using JS::dbg::AutoEntryMonitor;
using JS::dbg::Builder;
using js::frontend::IsIdentifier;
using mozilla::ArrayLength;
using mozilla::DebugOnly;
using mozilla::MakeScopeExit;
using mozilla::Maybe;
using mozilla::UniquePtr;


/*** Forward declarations ************************************************************************/

extern const Class DebuggerFrame_class;

enum {
    JSSLOT_DEBUGFRAME_OWNER,
    JSSLOT_DEBUGFRAME_ARGUMENTS,
    JSSLOT_DEBUGFRAME_ONSTEP_HANDLER,
    JSSLOT_DEBUGFRAME_ONPOP_HANDLER,
    JSSLOT_DEBUGFRAME_COUNT
};

extern const Class DebuggerArguments_class;

enum {
    JSSLOT_DEBUGARGUMENTS_FRAME,
    JSSLOT_DEBUGARGUMENTS_COUNT
};

extern const Class DebuggerEnv_class;

enum {
    JSSLOT_DEBUGENV_OWNER,
    JSSLOT_DEBUGENV_COUNT
};

extern const Class DebuggerObject_class;

enum {
    JSSLOT_DEBUGOBJECT_OWNER,
    JSSLOT_DEBUGOBJECT_COUNT
};

extern const Class DebuggerScript_class;

enum {
    JSSLOT_DEBUGSCRIPT_OWNER,
    JSSLOT_DEBUGSCRIPT_COUNT
};

extern const Class DebuggerSource_class;

enum {
    JSSLOT_DEBUGSOURCE_OWNER,
    JSSLOT_DEBUGSOURCE_TEXT,
    JSSLOT_DEBUGSOURCE_COUNT
};

void DebuggerObject_trace(JSTracer* trc, JSObject* obj);
void DebuggerEnv_trace(JSTracer* trc, JSObject* obj);
void DebuggerScript_trace(JSTracer* trc, JSObject* obj);
void DebuggerSource_trace(JSTracer* trc, JSObject* obj);


/*** Utils ***************************************************************************************/

static inline bool
EnsureFunctionHasScript(JSContext* cx, HandleFunction fun)
{
    if (fun->isInterpretedLazy()) {
        AutoCompartment ac(cx, fun);
        return !!fun->getOrCreateScript(cx);
    }
    return true;
}

static inline JSScript*
GetOrCreateFunctionScript(JSContext* cx, HandleFunction fun)
{
    MOZ_ASSERT(fun->isInterpreted());
    if (!EnsureFunctionHasScript(cx, fun))
        return nullptr;
    return fun->nonLazyScript();
}

static bool
ValueToIdentifier(JSContext* cx, HandleValue v, MutableHandleId id)
{
    if (!ValueToId<CanGC>(cx, v, id))
        return false;
    if (!JSID_IS_ATOM(id) || !IsIdentifier(JSID_TO_ATOM(id))) {
        RootedValue val(cx, v);
        ReportValueErrorFlags(cx, JSREPORT_ERROR, JSMSG_UNEXPECTED_TYPE,
                              JSDVG_SEARCH_STACK, val, nullptr, "not an identifier",
                              nullptr);
        return false;
    }
    return true;
}

/*
 * A range of all the Debugger.Frame objects for a particular AbstractFramePtr.
 *
 * FIXME This checks only current debuggers, so it relies on a hack in
 * Debugger::removeDebuggeeGlobal to make sure only current debuggers
 * have Frame objects with .live === true.
 */
class Debugger::FrameRange
{
    AbstractFramePtr frame;

    /* The debuggers in |fp|'s compartment, or nullptr if there are none. */
    GlobalObject::DebuggerVector* debuggers;

    /*
     * The index of the front Debugger.Frame's debugger in debuggers.
     * nextDebugger < debuggerCount if and only if the range is not empty.
     */
    size_t debuggerCount, nextDebugger;

    /*
     * If the range is not empty, this is front Debugger.Frame's entry in its
     * debugger's frame table.
     */
    FrameMap::Ptr entry;

  public:
    /*
     * Return a range containing all Debugger.Frame instances referring to
     * |fp|. |global| is |fp|'s global object; if nullptr or omitted, we
     * compute it ourselves from |fp|.
     *
     * We keep an index into the compartment's debugger list, and a
     * FrameMap::Ptr into the current debugger's frame map. Thus, if the set of
     * debuggers in |fp|'s compartment changes, this range becomes invalid.
     * Similarly, if stack frames are added to or removed from frontDebugger(),
     * then the range's front is invalid until popFront is called.
     */
    explicit FrameRange(AbstractFramePtr frame, GlobalObject* global = nullptr)
      : frame(frame)
    {
        nextDebugger = 0;

        /* Find our global, if we were not given one. */
        if (!global)
            global = &frame.script()->global();

        /* The frame and global must match. */
        MOZ_ASSERT(&frame.script()->global() == global);

        /* Find the list of debuggers we'll iterate over. There may be none. */
        debuggers = global->getDebuggers();
        if (debuggers) {
            debuggerCount = debuggers->length();
            findNext();
        } else {
            debuggerCount = 0;
        }
    }

    bool empty() const {
        return nextDebugger >= debuggerCount;
    }

    NativeObject* frontFrame() const {
        MOZ_ASSERT(!empty());
        return entry->value();
    }

    Debugger* frontDebugger() const {
        MOZ_ASSERT(!empty());
        return (*debuggers)[nextDebugger];
    }

    /*
     * Delete the front frame from its Debugger's frame map. After this call,
     * the range's front is invalid until popFront is called.
     */
    void removeFrontFrame() const {
        MOZ_ASSERT(!empty());
        frontDebugger()->frames.remove(entry);
    }

    void popFront() {
        MOZ_ASSERT(!empty());
        nextDebugger++;
        findNext();
    }

  private:
    /*
     * Either make this range refer to the first appropriate Debugger.Frame at
     * or after nextDebugger, or make it empty.
     */
    void findNext() {
        while (!empty()) {
            Debugger* dbg = (*debuggers)[nextDebugger];
            entry = dbg->frames.lookup(frame);
            if (entry)
                break;
            nextDebugger++;
        }
    }
};


/*** Breakpoints *********************************************************************************/

BreakpointSite::BreakpointSite(JSScript* script, jsbytecode* pc)
  : script(script), pc(pc), enabledCount(0)
{
    MOZ_ASSERT(!script->hasBreakpointsAt(pc));
    JS_INIT_CLIST(&breakpoints);
}

void
BreakpointSite::recompile(FreeOp* fop)
{
    if (script->hasBaselineScript())
        script->baselineScript()->toggleDebugTraps(script, pc);
}

void
BreakpointSite::inc(FreeOp* fop)
{
    enabledCount++;
    if (enabledCount == 1)
        recompile(fop);
}

void
BreakpointSite::dec(FreeOp* fop)
{
    MOZ_ASSERT(enabledCount > 0);
    enabledCount--;
    if (enabledCount == 0)
        recompile(fop);
}

void
BreakpointSite::destroyIfEmpty(FreeOp* fop)
{
    if (JS_CLIST_IS_EMPTY(&breakpoints))
        script->destroyBreakpointSite(fop, pc);
}

Breakpoint*
BreakpointSite::firstBreakpoint() const
{
    if (JS_CLIST_IS_EMPTY(&breakpoints))
        return nullptr;
    return Breakpoint::fromSiteLinks(JS_NEXT_LINK(&breakpoints));
}

bool
BreakpointSite::hasBreakpoint(Breakpoint* bp)
{
    for (Breakpoint* p = firstBreakpoint(); p; p = p->nextInSite())
        if (p == bp)
            return true;
    return false;
}

Breakpoint::Breakpoint(Debugger* debugger, BreakpointSite* site, JSObject* handler)
    : debugger(debugger), site(site), handler(handler)
{
    MOZ_ASSERT(handler->compartment() == debugger->object->compartment());
    JS_APPEND_LINK(&debuggerLinks, &debugger->breakpoints);
    JS_APPEND_LINK(&siteLinks, &site->breakpoints);
}

Breakpoint*
Breakpoint::fromDebuggerLinks(JSCList* links)
{
    return (Breakpoint*) ((unsigned char*) links - offsetof(Breakpoint, debuggerLinks));
}

Breakpoint*
Breakpoint::fromSiteLinks(JSCList* links)
{
    return (Breakpoint*) ((unsigned char*) links - offsetof(Breakpoint, siteLinks));
}

void
Breakpoint::destroy(FreeOp* fop)
{
    if (debugger->enabled)
        site->dec(fop);
    JS_REMOVE_LINK(&debuggerLinks);
    JS_REMOVE_LINK(&siteLinks);
    site->destroyIfEmpty(fop);
    fop->delete_(this);
}

Breakpoint*
Breakpoint::nextInDebugger()
{
    JSCList* link = JS_NEXT_LINK(&debuggerLinks);
    return (link == &debugger->breakpoints) ? nullptr : fromDebuggerLinks(link);
}

Breakpoint*
Breakpoint::nextInSite()
{
    JSCList* link = JS_NEXT_LINK(&siteLinks);
    return (link == &site->breakpoints) ? nullptr : fromSiteLinks(link);
}


/*** Debugger hook dispatch **********************************************************************/

Debugger::Debugger(JSContext* cx, NativeObject* dbg)
  : object(dbg),
    uncaughtExceptionHook(nullptr),
    enabled(true),
    allowUnobservedAsmJS(false),
    collectCoverageInfo(false),
    observedGCs(cx),
    tenurePromotionsLog(cx),
    trackingTenurePromotions(false),
    maxTenurePromotionsLogLength(DEFAULT_MAX_LOG_LENGTH),
    tenurePromotionsLogOverflowed(false),
    allocationsLog(cx),
    trackingAllocationSites(false),
    allocationSamplingProbability(1.0),
    maxAllocationsLogLength(DEFAULT_MAX_LOG_LENGTH),
    allocationsLogOverflowed(false),
    frames(cx->runtime()),
    scripts(cx),
    sources(cx),
    objects(cx),
    environments(cx),
#ifdef NIGHTLY_BUILD
    traceLoggerLastDrainedId(0),
    traceLoggerLastDrainedIteration(0),
#endif
    traceLoggerScriptedCallsLastDrainedId(0),
    traceLoggerScriptedCallsLastDrainedIteration(0)
{
    assertSameCompartment(cx, dbg);

    cx->runtime()->debuggerList.insertBack(this);
    JS_INIT_CLIST(&breakpoints);
    JS_INIT_CLIST(&onNewGlobalObjectWatchersLink);
}

Debugger::~Debugger()
{
    MOZ_ASSERT_IF(debuggees.initialized(), debuggees.empty());
    allocationsLog.clear();
    tenurePromotionsLog.clear();

    /*
     * Since the inactive state for this link is a singleton cycle, it's always
     * safe to apply JS_REMOVE_LINK to it, regardless of whether we're in the list or not.
     *
     * We don't have to worry about locking here since Debugger is not
     * background finalized.
     */
    JS_REMOVE_LINK(&onNewGlobalObjectWatchersLink);
}

bool
Debugger::init(JSContext* cx)
{
    bool ok = debuggees.init() &&
              debuggeeZones.init() &&
              frames.init() &&
              scripts.init() &&
              sources.init() &&
              objects.init() &&
              observedGCs.init() &&
              environments.init();
    if (!ok)
        ReportOutOfMemory(cx);
    return ok;
}

JS_STATIC_ASSERT(unsigned(JSSLOT_DEBUGFRAME_OWNER) == unsigned(JSSLOT_DEBUGSCRIPT_OWNER));
JS_STATIC_ASSERT(unsigned(JSSLOT_DEBUGFRAME_OWNER) == unsigned(JSSLOT_DEBUGSOURCE_OWNER));
JS_STATIC_ASSERT(unsigned(JSSLOT_DEBUGFRAME_OWNER) == unsigned(JSSLOT_DEBUGOBJECT_OWNER));
JS_STATIC_ASSERT(unsigned(JSSLOT_DEBUGFRAME_OWNER) == unsigned(JSSLOT_DEBUGENV_OWNER));

/* static */ Debugger*
Debugger::fromChildJSObject(JSObject* obj)
{
    MOZ_ASSERT(obj->getClass() == &DebuggerFrame_class ||
               obj->getClass() == &DebuggerScript_class ||
               obj->getClass() == &DebuggerSource_class ||
               obj->getClass() == &DebuggerObject_class ||
               obj->getClass() == &DebuggerEnv_class);
    JSObject* dbgobj = &obj->as<NativeObject>().getReservedSlot(JSSLOT_DEBUGOBJECT_OWNER).toObject();
    return fromJSObject(dbgobj);
}

bool
Debugger::hasMemory() const
{
    return object->getReservedSlot(JSSLOT_DEBUG_MEMORY_INSTANCE).isObject();
}

DebuggerMemory&
Debugger::memory() const
{
    MOZ_ASSERT(hasMemory());
    return object->getReservedSlot(JSSLOT_DEBUG_MEMORY_INSTANCE).toObject().as<DebuggerMemory>();
}

bool
Debugger::getScriptFrameWithIter(JSContext* cx, AbstractFramePtr frame,
                                 const ScriptFrameIter* maybeIter, MutableHandleValue vp)
{
    MOZ_ASSERT_IF(maybeIter, maybeIter->abstractFramePtr() == frame);

    FrameMap::AddPtr p = frames.lookupForAdd(frame);
    if (!p) {
        /* Create and populate the Debugger.Frame object. */
        RootedObject proto(cx, &object->getReservedSlot(JSSLOT_DEBUG_FRAME_PROTO).toObject());
        RootedNativeObject frameobj(cx, NewNativeObjectWithGivenProto(cx, &DebuggerFrame_class,
                                                                      proto));
        if (!frameobj)
            return false;

        // Eagerly copy ScriptFrameIter data if we've already walked the
        // stack.
        if (maybeIter) {
            AbstractFramePtr data = maybeIter->copyDataAsAbstractFramePtr();
            if (!data)
                return false;
            frameobj->setPrivate(data.raw());
        } else {
            frameobj->setPrivate(frame.raw());
        }

        frameobj->setReservedSlot(JSSLOT_DEBUGFRAME_OWNER, ObjectValue(*object));

        if (!ensureExecutionObservabilityOfFrame(cx, frame))
            return false;

        if (!frames.add(p, frame, frameobj)) {
            ReportOutOfMemory(cx);
            return false;
        }
    }
    vp.setObject(*p->value());
    return true;
}

/* static */ bool
Debugger::hasLiveHook(GlobalObject* global, Hook which)
{
    if (GlobalObject::DebuggerVector* debuggers = global->getDebuggers()) {
        for (Debugger** p = debuggers->begin(); p != debuggers->end(); p++) {
            Debugger* dbg = *p;
            if (dbg->enabled && dbg->getHook(which))
                return true;
        }
    }
    return false;
}

JSObject*
Debugger::getHook(Hook hook) const
{
    MOZ_ASSERT(hook >= 0 && hook < HookCount);
    const Value& v = object->getReservedSlot(JSSLOT_DEBUG_HOOK_START + hook);
    return v.isUndefined() ? nullptr : &v.toObject();
}

bool
Debugger::hasAnyLiveHooks() const
{
    if (!enabled)
        return false;

    if (getHook(OnDebuggerStatement) ||
        getHook(OnExceptionUnwind) ||
        getHook(OnNewScript) ||
        getHook(OnEnterFrame))
    {
        return true;
    }

    /* If any breakpoints are in live scripts, return true. */
    for (Breakpoint* bp = firstBreakpoint(); bp; bp = bp->nextInDebugger()) {
        if (IsMarkedUnbarriered(&bp->site->script))
            return true;
    }

    for (FrameMap::Range r = frames.all(); !r.empty(); r.popFront()) {
        NativeObject* frameObj = r.front().value();
        if (!frameObj->getReservedSlot(JSSLOT_DEBUGFRAME_ONSTEP_HANDLER).isUndefined() ||
            !frameObj->getReservedSlot(JSSLOT_DEBUGFRAME_ONPOP_HANDLER).isUndefined())
            return true;
    }

    return false;
}

/* static */ JSTrapStatus
Debugger::slowPathOnEnterFrame(JSContext* cx, AbstractFramePtr frame)
{
    RootedValue rval(cx);
    JSTrapStatus status = dispatchHook(
        cx,
        [frame](Debugger* dbg) -> bool {
            return dbg->observesFrame(frame) && dbg->observesEnterFrame();
        },
        [&](Debugger* dbg) -> JSTrapStatus {
            return dbg->fireEnterFrame(cx, frame, &rval);
        });

    switch (status) {
      case JSTRAP_CONTINUE:
        break;

      case JSTRAP_THROW:
        cx->setPendingException(rval);
        break;

      case JSTRAP_ERROR:
        cx->clearPendingException();
        break;

      case JSTRAP_RETURN:
        frame.setReturnValue(rval);
        break;

      default:
        MOZ_CRASH("bad Debugger::onEnterFrame JSTrapStatus value");
    }

    return status;
}

static void
DebuggerFrame_maybeDecrementFrameScriptStepModeCount(FreeOp* fop, AbstractFramePtr frame,
                                                     NativeObject* frameobj);

static void
DebuggerFrame_freeScriptFrameIterData(FreeOp* fop, JSObject* obj);

/*
 * Handle leaving a frame with debuggers watching. |frameOk| indicates whether
 * the frame is exiting normally or abruptly. Set |cx|'s exception and/or
 * |cx->fp()|'s return value, and return a new success value.
 */
/* static */ bool
Debugger::slowPathOnLeaveFrame(JSContext* cx, AbstractFramePtr frame, bool frameOk)
{
    Handle<GlobalObject*> global = cx->global();

    // The onPop handler and associated clean up logic should not run multiple
    // times on the same frame. If slowPathOnLeaveFrame has already been
    // called, the frame will not be present in the Debugger frame maps.
    FrameRange frameRange(frame, global);
    if (frameRange.empty())
        return frameOk;

    auto frameMapsGuard = MakeScopeExit([&] {
        // Clean up all Debugger.Frame instances. This call creates a fresh
        // FrameRange, as one debugger's onPop handler could have caused another
        // debugger to create its own Debugger.Frame instance.
        removeFromFrameMapsAndClearBreakpointsIn(cx, frame);
    });

    /* Save the frame's completion value. */
    JSTrapStatus status;
    RootedValue value(cx);
    Debugger::resultToCompletion(cx, frameOk, frame.returnValue(), &status, &value);

    // This path can be hit via unwinding the stack due to over-recursion or
    // OOM. In those cases, don't fire the frames' onPop handlers, because
    // invoking JS will only trigger the same condition. See
    // slowPathOnExceptionUnwind.
    if (!cx->isThrowingOverRecursed() && !cx->isThrowingOutOfMemory()) {
        /* Build a list of the recipients. */
        AutoObjectVector frames(cx);
        for (; !frameRange.empty(); frameRange.popFront()) {
            if (!frames.append(frameRange.frontFrame())) {
                cx->clearPendingException();
                return false;
            }
        }

        /* For each Debugger.Frame, fire its onPop handler, if any. */
        for (JSObject** p = frames.begin(); p != frames.end(); p++) {
            RootedNativeObject frameobj(cx, &(*p)->as<NativeObject>());
            Debugger* dbg = Debugger::fromChildJSObject(frameobj);

            if (dbg->enabled &&
                !frameobj->getReservedSlot(JSSLOT_DEBUGFRAME_ONPOP_HANDLER).isUndefined()) {
                RootedValue handler(cx, frameobj->getReservedSlot(JSSLOT_DEBUGFRAME_ONPOP_HANDLER));

                Maybe<AutoCompartment> ac;
                ac.emplace(cx, dbg->object);

                RootedValue completion(cx);
                if (!dbg->newCompletionValue(cx, status, value, &completion)) {
                    status = dbg->handleUncaughtException(ac, false);
                    break;
                }

                /* Call the onPop handler. */
                RootedValue rval(cx);
                bool hookOk = Invoke(cx, ObjectValue(*frameobj), handler, 1, completion.address(),
                                     &rval);
                RootedValue nextValue(cx);
                JSTrapStatus nextStatus = dbg->parseResumptionValue(ac, hookOk, rval, &nextValue);

                /*
                 * At this point, we are back in the debuggee compartment, and any error has
                 * been wrapped up as a completion value.
                 */
                MOZ_ASSERT(cx->compartment() == global->compartment());
                MOZ_ASSERT(!cx->isExceptionPending());

                /* JSTRAP_CONTINUE means "make no change". */
                if (nextStatus != JSTRAP_CONTINUE) {
                    status = nextStatus;
                    value = nextValue;
                }
            }
        }
    }

    /* Establish (status, value) as our resumption value. */
    switch (status) {
      case JSTRAP_RETURN:
        frame.setReturnValue(value);
        return true;

      case JSTRAP_THROW:
        cx->setPendingException(value);
        return false;

      case JSTRAP_ERROR:
        MOZ_ASSERT(!cx->isExceptionPending());
        return false;

      default:
        MOZ_CRASH("bad final trap status");
    }
}

/* static */ JSTrapStatus
Debugger::slowPathOnDebuggerStatement(JSContext* cx, AbstractFramePtr frame)
{
    RootedValue rval(cx);
    JSTrapStatus status = dispatchHook(
        cx,
        [](Debugger* dbg) -> bool { return dbg->getHook(OnDebuggerStatement); },
        [&](Debugger* dbg) -> JSTrapStatus {
            return dbg->fireDebuggerStatement(cx, &rval);
        });

    switch (status) {
      case JSTRAP_CONTINUE:
      case JSTRAP_ERROR:
        break;

      case JSTRAP_RETURN:
        frame.setReturnValue(rval);
        break;

      case JSTRAP_THROW:
        cx->setPendingException(rval);
        break;

      default:
        MOZ_CRASH("Invalid onDebuggerStatement trap status");
    }

    return status;
}

/* static */ JSTrapStatus
Debugger::slowPathOnExceptionUnwind(JSContext* cx, AbstractFramePtr frame)
{
    // Invoking more JS on an over-recursed stack or after OOM is only going
    // to result in more of the same error.
    if (cx->isThrowingOverRecursed() || cx->isThrowingOutOfMemory())
        return JSTRAP_CONTINUE;

    RootedValue rval(cx);
    JSTrapStatus status = dispatchHook(
        cx,
        [](Debugger* dbg) -> bool { return dbg->getHook(OnExceptionUnwind); },
        [&](Debugger* dbg) -> JSTrapStatus {
            return dbg->fireExceptionUnwind(cx, &rval);
        });

    switch (status) {
      case JSTRAP_CONTINUE:
        break;

      case JSTRAP_THROW:
        cx->setPendingException(rval);
        break;

      case JSTRAP_ERROR:
        cx->clearPendingException();
        break;

      case JSTRAP_RETURN:
        cx->clearPendingException();
        frame.setReturnValue(rval);
        break;

      default:
        MOZ_CRASH("Invalid onExceptionUnwind trap status");
    }

    return status;
}

bool
Debugger::wrapEnvironment(JSContext* cx, Handle<Env*> env, MutableHandleValue rval)
{
    if (!env) {
        rval.setNull();
        return true;
    }

    /*
     * DebuggerEnv should only wrap a debug scope chain obtained (transitively)
     * from GetDebugScopeFor(Frame|Function).
     */
    MOZ_ASSERT(!IsSyntacticScope(env));

    NativeObject* envobj;
    DependentAddPtr<ObjectWeakMap> p(cx, environments, env);
    if (p) {
        envobj = &p->value()->as<NativeObject>();
    } else {
        /* Create a new Debugger.Environment for env. */
        RootedObject proto(cx, &object->getReservedSlot(JSSLOT_DEBUG_ENV_PROTO).toObject());
        envobj = NewNativeObjectWithGivenProto(cx, &DebuggerEnv_class, proto,
                                               TenuredObject);
        if (!envobj)
            return false;
        envobj->setPrivateGCThing(env);
        envobj->setReservedSlot(JSSLOT_DEBUGENV_OWNER, ObjectValue(*object));
        if (!p.add(cx, environments, env, envobj))
            return false;

        CrossCompartmentKey key(CrossCompartmentKey::DebuggerEnvironment, object, env);
        if (!object->compartment()->putWrapper(cx, key, ObjectValue(*envobj))) {
            environments.remove(env);
            ReportOutOfMemory(cx);
            return false;
        }
    }
    rval.setObject(*envobj);
    return true;
}

bool
Debugger::wrapDebuggeeValue(JSContext* cx, MutableHandleValue vp)
{
    assertSameCompartment(cx, object.get());

    if (vp.isObject()) {
        RootedObject obj(cx, &vp.toObject());

        if (obj->is<JSFunction>()) {
            MOZ_ASSERT(!IsInternalFunctionObject(*obj));
            RootedFunction fun(cx, &obj->as<JSFunction>());
            if (!EnsureFunctionHasScript(cx, fun))
                return false;
        }

        DependentAddPtr<ObjectWeakMap> p(cx, objects, obj);
        if (p) {
            vp.setObject(*p->value());
        } else {
            /* Create a new Debugger.Object for obj. */
            RootedObject proto(cx, &object->getReservedSlot(JSSLOT_DEBUG_OBJECT_PROTO).toObject());
            NativeObject* dobj =
                NewNativeObjectWithGivenProto(cx, &DebuggerObject_class, proto,
                                              TenuredObject);
            if (!dobj)
                return false;
            dobj->setPrivateGCThing(obj);
            dobj->setReservedSlot(JSSLOT_DEBUGOBJECT_OWNER, ObjectValue(*object));

            if (!p.add(cx, objects, obj, dobj))
                return false;

            if (obj->compartment() != object->compartment()) {
                CrossCompartmentKey key(CrossCompartmentKey::DebuggerObject, object, obj);
                if (!object->compartment()->putWrapper(cx, key, ObjectValue(*dobj))) {
                    objects.remove(obj);
                    ReportOutOfMemory(cx);
                    return false;
                }
            }

            vp.setObject(*dobj);
        }
    } else if (vp.isMagic()) {
        RootedPlainObject optObj(cx, NewBuiltinClassInstance<PlainObject>(cx));
        if (!optObj)
            return false;

        // We handle three sentinel values: missing arguments (overloading
        // JS_OPTIMIZED_ARGUMENTS), optimized out slots (JS_OPTIMIZED_OUT),
        // and uninitialized bindings (JS_UNINITIALIZED_LEXICAL).
        //
        // Other magic values should not have escaped.
        PropertyName* name;
        switch (vp.whyMagic()) {
          case JS_OPTIMIZED_ARGUMENTS:   name = cx->names().missingArguments; break;
          case JS_OPTIMIZED_OUT:         name = cx->names().optimizedOut; break;
          case JS_UNINITIALIZED_LEXICAL: name = cx->names().uninitialized; break;
          default: MOZ_CRASH("Unsupported magic value escaped to Debugger");
        }

        RootedValue trueVal(cx, BooleanValue(true));
        if (!DefineProperty(cx, optObj, name, trueVal))
            return false;

        vp.setObject(*optObj);
    } else if (!cx->compartment()->wrap(cx, vp)) {
        vp.setUndefined();
        return false;
    }

    return true;
}

bool
Debugger::unwrapDebuggeeObject(JSContext* cx, MutableHandleObject obj)
{
    if (obj->getClass() != &DebuggerObject_class) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NOT_EXPECTED_TYPE,
                             "Debugger", "Debugger.Object", obj->getClass()->name);
        return false;
    }
    NativeObject* ndobj = &obj->as<NativeObject>();

    Value owner = ndobj->getReservedSlot(JSSLOT_DEBUGOBJECT_OWNER);
    if (owner.isUndefined() || &owner.toObject() != object) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                             owner.isUndefined()
                             ? JSMSG_DEBUG_OBJECT_PROTO
                             : JSMSG_DEBUG_OBJECT_WRONG_OWNER);
        return false;
    }

    obj.set(static_cast<JSObject*>(ndobj->getPrivate()));
    return true;
}

bool
Debugger::unwrapDebuggeeValue(JSContext* cx, MutableHandleValue vp)
{
    assertSameCompartment(cx, object.get(), vp);
    if (vp.isObject()) {
        RootedObject dobj(cx, &vp.toObject());
        if (!unwrapDebuggeeObject(cx, &dobj))
            return false;
        vp.setObject(*dobj);
    }
    return true;
}

static bool
CheckArgCompartment(JSContext* cx, JSObject* obj, JSObject* arg,
                    const char* methodname, const char* propname)
{
    if (arg->compartment() != obj->compartment()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_COMPARTMENT_MISMATCH,
                             methodname, propname);
        return false;
    }
    return true;
}

static bool
CheckArgCompartment(JSContext* cx, JSObject* obj, HandleValue v,
                    const char* methodname, const char* propname)
{
    if (v.isObject())
        return CheckArgCompartment(cx, obj, &v.toObject(), methodname, propname);
    return true;
}

bool
Debugger::unwrapPropertyDescriptor(JSContext* cx, HandleObject obj,
                                   MutableHandle<PropertyDescriptor> desc)
{
    if (desc.hasValue()) {
        RootedValue value(cx, desc.value());
        if (!unwrapDebuggeeValue(cx, &value) ||
            !CheckArgCompartment(cx, obj, value, "defineProperty", "value"))
        {
            return false;
        }
        desc.setValue(value);
    }

    if (desc.hasGetterObject()) {
        RootedObject get(cx, desc.getterObject());
        if (get) {
            if (!unwrapDebuggeeObject(cx, &get))
                return false;
            if (!CheckArgCompartment(cx, obj, get, "defineProperty", "get"))
                return false;
        }
        desc.setGetterObject(get);
    }

    if (desc.hasSetterObject()) {
        RootedObject set(cx, desc.setterObject());
        if (set) {
            if (!unwrapDebuggeeObject(cx, &set))
                return false;
            if (!CheckArgCompartment(cx, obj, set, "defineProperty", "set"))
                return false;
        }
        desc.setSetterObject(set);
    }

    return true;
}

JSTrapStatus
Debugger::handleUncaughtExceptionHelper(Maybe<AutoCompartment>& ac,
                                        MutableHandleValue* vp, bool callHook)
{
    JSContext* cx = ac->context()->asJSContext();
    if (cx->isExceptionPending()) {
        if (callHook && uncaughtExceptionHook) {
            RootedValue exc(cx);
            if (!cx->getPendingException(&exc))
                return JSTRAP_ERROR;
            cx->clearPendingException();
            RootedValue fval(cx, ObjectValue(*uncaughtExceptionHook));
            RootedValue rv(cx);
            if (Invoke(cx, ObjectValue(*object), fval, 1, exc.address(), &rv))
                return vp ? parseResumptionValue(ac, true, rv, *vp, false) : JSTRAP_CONTINUE;
        }

        if (cx->isExceptionPending()) {
            JS_ReportPendingException(cx);
            cx->clearPendingException();
        }
    }
    ac.reset();
    return JSTRAP_ERROR;
}

JSTrapStatus
Debugger::handleUncaughtException(Maybe<AutoCompartment>& ac, MutableHandleValue vp, bool callHook)
{
    return handleUncaughtExceptionHelper(ac, &vp, callHook);
}

JSTrapStatus
Debugger::handleUncaughtException(Maybe<AutoCompartment>& ac, bool callHook)
{
    return handleUncaughtExceptionHelper(ac, nullptr, callHook);
}

/* static */ void
Debugger::resultToCompletion(JSContext* cx, bool ok, const Value& rv,
                             JSTrapStatus* status, MutableHandleValue value)
{
    MOZ_ASSERT_IF(ok, !cx->isExceptionPending());

    if (ok) {
        *status = JSTRAP_RETURN;
        value.set(rv);
    } else if (cx->isExceptionPending()) {
        *status = JSTRAP_THROW;
        if (!cx->getPendingException(value))
            *status = JSTRAP_ERROR;
        cx->clearPendingException();
    } else {
        *status = JSTRAP_ERROR;
        value.setUndefined();
    }
}

bool
Debugger::newCompletionValue(JSContext* cx, JSTrapStatus status, Value value_,
                             MutableHandleValue result)
{
    /*
     * We must be in the debugger's compartment, since that's where we want
     * to construct the completion value.
     */
    assertSameCompartment(cx, object.get());

    RootedId key(cx);
    RootedValue value(cx, value_);

    switch (status) {
      case JSTRAP_RETURN:
        key = NameToId(cx->names().return_);
        break;

      case JSTRAP_THROW:
        key = NameToId(cx->names().throw_);
        break;

      case JSTRAP_ERROR:
        result.setNull();
        return true;

      default:
        MOZ_CRASH("bad status passed to Debugger::newCompletionValue");
    }

    /* Common tail for JSTRAP_RETURN and JSTRAP_THROW. */
    RootedPlainObject obj(cx, NewBuiltinClassInstance<PlainObject>(cx));
    if (!obj ||
        !wrapDebuggeeValue(cx, &value) ||
        !NativeDefineProperty(cx, obj, key, value, nullptr, nullptr, JSPROP_ENUMERATE))
    {
        return false;
    }

    result.setObject(*obj);
    return true;
}

bool
Debugger::receiveCompletionValue(Maybe<AutoCompartment>& ac, bool ok,
                                 HandleValue val,
                                 MutableHandleValue vp)
{
    JSContext* cx = ac->context()->asJSContext();

    JSTrapStatus status;
    RootedValue value(cx);
    resultToCompletion(cx, ok, val, &status, &value);
    ac.reset();
    return newCompletionValue(cx, status, value, vp);
}

static bool
GetStatusProperty(JSContext* cx, HandleObject obj, HandlePropertyName name, JSTrapStatus status,
                  JSTrapStatus* statusOut, MutableHandleValue vp, int* hits)
{
    bool found;
    if (!HasProperty(cx, obj, name, &found))
        return false;
    if (found) {
        ++*hits;
        *statusOut = status;
        if (!GetProperty(cx, obj, obj, name, vp))
            return false;
    }
    return true;
}

static bool
ParseResumptionValueAsObject(JSContext* cx, HandleValue rv, JSTrapStatus* statusp,
                             MutableHandleValue vp)
{
    int hits = 0;
    if (rv.isObject()) {
        RootedObject obj(cx, &rv.toObject());
        if (!GetStatusProperty(cx, obj, cx->names().return_, JSTRAP_RETURN, statusp, vp, &hits))
            return false;
        if (!GetStatusProperty(cx, obj, cx->names().throw_, JSTRAP_THROW, statusp, vp, &hits))
            return false;
    }

    if (hits != 1) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_BAD_RESUMPTION);
        return false;
    }
    return true;
}

JSTrapStatus
Debugger::parseResumptionValue(Maybe<AutoCompartment>& ac, bool ok, const Value& rv, MutableHandleValue vp,
                               bool callHook)
{
    vp.setUndefined();
    if (!ok)
        return handleUncaughtException(ac, vp, callHook);
    if (rv.isUndefined()) {
        ac.reset();
        return JSTRAP_CONTINUE;
    }
    if (rv.isNull()) {
        ac.reset();
        return JSTRAP_ERROR;
    }

    JSContext* cx = ac->context()->asJSContext();
    JSTrapStatus status = JSTRAP_CONTINUE;
    RootedValue v(cx);
    RootedValue rvRoot(cx, rv);
    if (!ParseResumptionValueAsObject(cx, rvRoot, &status, &v) ||
        !unwrapDebuggeeValue(cx, &v))
    {
        return handleUncaughtException(ac, vp, callHook);
    }

    ac.reset();
    if (!cx->compartment()->wrap(cx, &v)) {
        vp.setUndefined();
        return JSTRAP_ERROR;
    }
    vp.set(v);

    return status;
}

static bool
CallMethodIfPresent(JSContext* cx, HandleObject obj, const char* name, int argc, Value* argv,
                    MutableHandleValue rval)
{
    rval.setUndefined();
    JSAtom* atom = Atomize(cx, name, strlen(name));
    if (!atom)
        return false;

    RootedId id(cx, AtomToId(atom));
    RootedValue fval(cx);
    return GetProperty(cx, obj, obj, id, &fval) &&
           (!IsCallable(fval) || Invoke(cx, ObjectValue(*obj), fval, argc, argv, rval));
}

JSTrapStatus
Debugger::fireDebuggerStatement(JSContext* cx, MutableHandleValue vp)
{
    RootedObject hook(cx, getHook(OnDebuggerStatement));
    MOZ_ASSERT(hook);
    MOZ_ASSERT(hook->isCallable());

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, object);

    ScriptFrameIter iter(cx);
    RootedValue scriptFrame(cx);
    if (!getScriptFrame(cx, iter, &scriptFrame))
        return handleUncaughtException(ac, false);

    RootedValue rv(cx);
    bool ok = Invoke(cx, ObjectValue(*object), ObjectValue(*hook), 1, scriptFrame.address(), &rv);
    return parseResumptionValue(ac, ok, rv, vp);
}

JSTrapStatus
Debugger::fireExceptionUnwind(JSContext* cx, MutableHandleValue vp)
{
    RootedObject hook(cx, getHook(OnExceptionUnwind));
    MOZ_ASSERT(hook);
    MOZ_ASSERT(hook->isCallable());

    RootedValue exc(cx);
    if (!cx->getPendingException(&exc))
        return JSTRAP_ERROR;
    cx->clearPendingException();

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, object);

    JS::AutoValueArray<2> argv(cx);
    argv[0].setUndefined();
    argv[1].set(exc);

    ScriptFrameIter iter(cx);
    if (!getScriptFrame(cx, iter, argv[0]) || !wrapDebuggeeValue(cx, argv[1]))
        return handleUncaughtException(ac, false);

    RootedValue rv(cx);
    bool ok = Invoke(cx, ObjectValue(*object), ObjectValue(*hook), 2, argv.begin(), &rv);
    JSTrapStatus st = parseResumptionValue(ac, ok, rv, vp);
    if (st == JSTRAP_CONTINUE)
        cx->setPendingException(exc);
    return st;
}

JSTrapStatus
Debugger::fireEnterFrame(JSContext* cx, AbstractFramePtr frame, MutableHandleValue vp)
{
    RootedObject hook(cx, getHook(OnEnterFrame));
    MOZ_ASSERT(hook);
    MOZ_ASSERT(hook->isCallable());

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, object);

    RootedValue scriptFrame(cx);
    if (!getScriptFrame(cx, frame, &scriptFrame))
        return handleUncaughtException(ac, false);

    RootedValue rv(cx);
    bool ok = Invoke(cx, ObjectValue(*object), ObjectValue(*hook), 1, scriptFrame.address(), &rv);
    return parseResumptionValue(ac, ok, rv, vp);
}

void
Debugger::fireNewScript(JSContext* cx, HandleScript script)
{
    RootedObject hook(cx, getHook(OnNewScript));
    MOZ_ASSERT(hook);
    MOZ_ASSERT(hook->isCallable());

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, object);

    JSObject* dsobj = wrapScript(cx, script);
    if (!dsobj) {
        handleUncaughtException(ac, false);
        return;
    }

    RootedValue scriptObject(cx, ObjectValue(*dsobj));
    RootedValue rv(cx);
    if (!Invoke(cx, ObjectValue(*object), ObjectValue(*hook), 1, scriptObject.address(), &rv))
        handleUncaughtException(ac, true);
}

void
Debugger::fireOnGarbageCollectionHook(JSContext* cx,
                                      const JS::dbg::GarbageCollectionEvent::Ptr& gcData)
{
    MOZ_ASSERT(observedGC(gcData->majorGCNumber()));
    observedGCs.remove(gcData->majorGCNumber());

    RootedObject hook(cx, getHook(OnGarbageCollection));
    MOZ_ASSERT(hook);
    MOZ_ASSERT(hook->isCallable());

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, object);

    JSObject* dataObj = gcData->toJSObject(cx);
    if (!dataObj) {
        handleUncaughtException(ac, false);
        return;
    }

    RootedValue dataVal(cx, ObjectValue(*dataObj));
    RootedValue rv(cx);
    if (!Invoke(cx, ObjectValue(*object), ObjectValue(*hook), 1, dataVal.address(), &rv))
        handleUncaughtException(ac, true);
}

JSTrapStatus
Debugger::fireOnIonCompilationHook(JSContext* cx, Handle<ScriptVector> scripts, LSprinter& graph)
{
    RootedObject hook(cx, getHook(OnIonCompilation));
    MOZ_ASSERT(hook);
    MOZ_ASSERT(hook->isCallable());

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, object);

    // Copy the vector of scripts to a JS Array of Debugger.Script
    RootedObject tmpObj(cx);
    RootedValue tmpVal(cx);
    AutoValueVector dbgScripts(cx);
    for (size_t i = 0; i < scripts.length(); i++) {
        tmpObj = wrapScript(cx, scripts[i]);
        if (!tmpObj)
            return handleUncaughtException(ac, false);

        tmpVal.setObject(*tmpObj);
        if (!dbgScripts.append(tmpVal))
            return handleUncaughtException(ac, false);
    }

    RootedObject dbgScriptsArray(cx, JS_NewArrayObject(cx, dbgScripts));
    if (!dbgScriptsArray)
        return handleUncaughtException(ac, false);

    // Copy the JSON compilation graph to a JS String which is allocated as part
    // of the Debugger compartment.
    Sprinter jsonPrinter(cx);
    if (!jsonPrinter.init())
        return handleUncaughtException(ac, false);

    graph.exportInto(jsonPrinter);
    if (jsonPrinter.hadOutOfMemory())
        return handleUncaughtException(ac, false);

    RootedString json(cx, JS_NewStringCopyZ(cx, jsonPrinter.string()));
    if (!json)
        return handleUncaughtException(ac, false);

    // Create a JS Object which has the array of scripts, and the string of the
    // JSON graph.
    const char* names[] = { "scripts", "json" };
    JS::AutoValueArray<2> values(cx);
    values[0].setObject(*dbgScriptsArray);
    values[1].setString(json);

    RootedObject obj(cx, JS_NewObject(cx, nullptr));
    if (!obj)
        return handleUncaughtException(ac, false);

    MOZ_ASSERT(mozilla::ArrayLength(names) == values.length());
    for (size_t i = 0; i < mozilla::ArrayLength(names); i++) {
        if (!JS_DefineProperty(cx, obj, names[i], values[i], JSPROP_ENUMERATE, nullptr, nullptr))
            return handleUncaughtException(ac, false);
    }

    // Call Debugger.onIonCompilation hook.
    JS::AutoValueArray<1> argv(cx);
    argv[0].setObject(*obj);

    RootedValue rv(cx);
    if (!Invoke(cx, ObjectValue(*object), ObjectValue(*hook), 1, argv.begin(), &rv))
        return handleUncaughtException(ac, true);
    return JSTRAP_CONTINUE;
}

template <typename HookIsEnabledFun /* bool (Debugger*) */,
          typename FireHookFun /* JSTrapStatus (Debugger*) */>
/* static */ JSTrapStatus
Debugger::dispatchHook(JSContext* cx, HookIsEnabledFun hookIsEnabled, FireHookFun fireHook)
{
    /*
     * Determine which debuggers will receive this event, and in what order.
     * Make a copy of the list, since the original is mutable and we will be
     * calling into arbitrary JS.
     *
     * Note: In the general case, 'triggered' contains references to objects in
     * different compartments--every compartment *except* this one.
     */
    AutoValueVector triggered(cx);
    Handle<GlobalObject*> global = cx->global();
    if (GlobalObject::DebuggerVector* debuggers = global->getDebuggers()) {
        for (Debugger** p = debuggers->begin(); p != debuggers->end(); p++) {
            Debugger* dbg = *p;
            if (dbg->enabled && hookIsEnabled(dbg)) {
                if (!triggered.append(ObjectValue(*dbg->toJSObject())))
                    return JSTRAP_ERROR;
            }
        }
    }

    /*
     * Deliver the event to each debugger, checking again to make sure it
     * should still be delivered.
     */
    for (Value* p = triggered.begin(); p != triggered.end(); p++) {
        Debugger* dbg = Debugger::fromJSObject(&p->toObject());
        if (dbg->debuggees.has(global) && dbg->enabled && hookIsEnabled(dbg)) {
            JSTrapStatus st = fireHook(dbg);
            if (st != JSTRAP_CONTINUE)
                return st;
        }
    }
    return JSTRAP_CONTINUE;
}

void
Debugger::slowPathOnNewScript(JSContext* cx, HandleScript script)
{
    JSTrapStatus status = dispatchHook(
        cx,
        [script](Debugger* dbg) -> bool {
            return dbg->observesNewScript() && dbg->observesScript(script);
        },
        [&](Debugger* dbg) -> JSTrapStatus {
            dbg->fireNewScript(cx, script);
            return JSTRAP_CONTINUE;
        });

    if (status == JSTRAP_ERROR) {
        ReportOutOfMemory(cx);
        return;
    }

    MOZ_ASSERT(status == JSTRAP_CONTINUE);
}

/* static */ JSTrapStatus
Debugger::onTrap(JSContext* cx, MutableHandleValue vp)
{
    ScriptFrameIter iter(cx);
    RootedScript script(cx, iter.script());
    MOZ_ASSERT(script->isDebuggee());
    Rooted<GlobalObject*> scriptGlobal(cx, &script->global());
    jsbytecode* pc = iter.pc();
    BreakpointSite* site = script->getBreakpointSite(pc);
    JSOp op = JSOp(*pc);

    /* Build list of breakpoint handlers. */
    Vector<Breakpoint*> triggered(cx);
    for (Breakpoint* bp = site->firstBreakpoint(); bp; bp = bp->nextInSite()) {
        if (!triggered.append(bp))
            return JSTRAP_ERROR;
    }

    for (Breakpoint** p = triggered.begin(); p != triggered.end(); p++) {
        Breakpoint* bp = *p;

        /* Handlers can clear breakpoints. Check that bp still exists. */
        if (!site || !site->hasBreakpoint(bp))
            continue;

        /*
         * There are two reasons we have to check whether dbg is enabled and
         * debugging scriptGlobal.
         *
         * One is just that one breakpoint handler can disable other Debuggers
         * or remove debuggees.
         *
         * The other has to do with non-compile-and-go scripts, which have no
         * specific global--until they are executed. Only now do we know which
         * global the script is running against.
         */
        Debugger* dbg = bp->debugger;
        if (dbg->enabled && dbg->debuggees.lookup(scriptGlobal)) {
            Maybe<AutoCompartment> ac;
            ac.emplace(cx, dbg->object);

            RootedValue scriptFrame(cx);
            if (!dbg->getScriptFrame(cx, iter, &scriptFrame))
                return dbg->handleUncaughtException(ac, false);
            RootedValue rv(cx);
            Rooted<JSObject*> handler(cx, bp->handler);
            bool ok = CallMethodIfPresent(cx, handler, "hit", 1, scriptFrame.address(), &rv);
            JSTrapStatus st = dbg->parseResumptionValue(ac, ok, rv, vp, true);
            if (st != JSTRAP_CONTINUE)
                return st;

            /* Calling JS code invalidates site. Reload it. */
            site = script->getBreakpointSite(pc);
        }
    }

    /* By convention, return the true op to the interpreter in vp. */
    vp.setInt32(op);
    return JSTRAP_CONTINUE;
}

/* static */ JSTrapStatus
Debugger::onSingleStep(JSContext* cx, MutableHandleValue vp)
{
    ScriptFrameIter iter(cx);

    /*
     * We may be stepping over a JSOP_EXCEPTION, that pushes the context's
     * pending exception for a 'catch' clause to handle. Don't let the
     * onStep handlers mess with that (other than by returning a resumption
     * value).
     */
    RootedValue exception(cx, UndefinedValue());
    bool exceptionPending = cx->isExceptionPending();
    if (exceptionPending) {
        if (!cx->getPendingException(&exception))
            return JSTRAP_ERROR;
        cx->clearPendingException();
    }

    /*
     * Build list of Debugger.Frame instances referring to this frame with
     * onStep handlers.
     */
    AutoObjectVector frames(cx);
    for (FrameRange r(iter.abstractFramePtr()); !r.empty(); r.popFront()) {
        NativeObject* frame = r.frontFrame();
        if (!frame->getReservedSlot(JSSLOT_DEBUGFRAME_ONSTEP_HANDLER).isUndefined() &&
            !frames.append(frame))
        {
            return JSTRAP_ERROR;
        }
    }

#ifdef DEBUG
    /*
     * Validate the single-step count on this frame's script, to ensure that
     * we're not receiving traps we didn't ask for. Even when frames is
     * non-empty (and thus we know this trap was requested), do the check
     * anyway, to make sure the count has the correct non-zero value.
     *
     * The converse --- ensuring that we do receive traps when we should --- can
     * be done with unit tests.
     */
    {
        uint32_t stepperCount = 0;
        JSScript* trappingScript = iter.script();
        GlobalObject* global = cx->global();
        if (GlobalObject::DebuggerVector* debuggers = global->getDebuggers()) {
            for (Debugger** p = debuggers->begin(); p != debuggers->end(); p++) {
                Debugger* dbg = *p;
                for (FrameMap::Range r = dbg->frames.all(); !r.empty(); r.popFront()) {
                    AbstractFramePtr frame = r.front().key();
                    NativeObject* frameobj = r.front().value();
                    if (frame.script() == trappingScript &&
                        !frameobj->getReservedSlot(JSSLOT_DEBUGFRAME_ONSTEP_HANDLER).isUndefined())
                    {
                        stepperCount++;
                    }
                }
            }
        }
        MOZ_ASSERT(stepperCount == trappingScript->stepModeCount());
    }
#endif

    /* Call all the onStep handlers we found. */
    for (JSObject** p = frames.begin(); p != frames.end(); p++) {
        RootedNativeObject frame(cx, &(*p)->as<NativeObject>());
        Debugger* dbg = Debugger::fromChildJSObject(frame);

        Maybe<AutoCompartment> ac;
        ac.emplace(cx, dbg->object);

        const Value& handler = frame->getReservedSlot(JSSLOT_DEBUGFRAME_ONSTEP_HANDLER);
        RootedValue rval(cx);
        bool ok = Invoke(cx, ObjectValue(*frame), handler, 0, nullptr, &rval);
        JSTrapStatus st = dbg->parseResumptionValue(ac, ok, rval, vp);
        if (st != JSTRAP_CONTINUE)
            return st;
    }

    vp.setUndefined();
    if (exceptionPending)
        cx->setPendingException(exception);
    return JSTRAP_CONTINUE;
}

JSTrapStatus
Debugger::fireNewGlobalObject(JSContext* cx, Handle<GlobalObject*> global, MutableHandleValue vp)
{
    RootedObject hook(cx, getHook(OnNewGlobalObject));
    MOZ_ASSERT(hook);
    MOZ_ASSERT(hook->isCallable());

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, object);

    RootedValue wrappedGlobal(cx, ObjectValue(*global));
    if (!wrapDebuggeeValue(cx, &wrappedGlobal))
        return handleUncaughtException(ac, false);

    RootedValue rv(cx);

    // onNewGlobalObject is infallible, and thus is only allowed to return
    // undefined as a resumption value. If it returns anything else, we throw.
    // And if that happens, or if the hook itself throws, we invoke the
    // uncaughtExceptionHook so that we never leave an exception pending on the
    // cx. This allows JS_NewGlobalObject to avoid handling failures from debugger
    // hooks.
    bool ok = Invoke(cx, ObjectValue(*object), ObjectValue(*hook), 1, wrappedGlobal.address(), &rv);
    if (ok && !rv.isUndefined()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                             JSMSG_DEBUG_RESUMPTION_VALUE_DISALLOWED);
        ok = false;
    }
    // NB: Even though we don't care about what goes into it, we have to pass vp
    // to handleUncaughtException so that it parses resumption values from the
    // uncaughtExceptionHook and tells the caller whether we should execute the
    // rest of the onNewGlobalObject hooks or not.
    JSTrapStatus status = ok ? JSTRAP_CONTINUE
                             : handleUncaughtException(ac, vp, true);
    MOZ_ASSERT(!cx->isExceptionPending());
    return status;
}

void
Debugger::slowPathOnNewGlobalObject(JSContext* cx, Handle<GlobalObject*> global)
{
    MOZ_ASSERT(!JS_CLIST_IS_EMPTY(&cx->runtime()->onNewGlobalObjectWatchers));
    if (global->compartment()->options().invisibleToDebugger())
        return;

    /*
     * Make a copy of the runtime's onNewGlobalObjectWatchers before running the
     * handlers. Since one Debugger's handler can disable another's, the list
     * can be mutated while we're walking it.
     */
    AutoObjectVector watchers(cx);
    for (JSCList* link = JS_LIST_HEAD(&cx->runtime()->onNewGlobalObjectWatchers);
         link != &cx->runtime()->onNewGlobalObjectWatchers;
         link = JS_NEXT_LINK(link))
    {
        Debugger* dbg = fromOnNewGlobalObjectWatchersLink(link);
        MOZ_ASSERT(dbg->observesNewGlobalObject());
        JSObject* obj = dbg->object;
        JS::ExposeObjectToActiveJS(obj);
        if (!watchers.append(obj))
            return;
    }

    JSTrapStatus status = JSTRAP_CONTINUE;
    RootedValue value(cx);

    for (size_t i = 0; i < watchers.length(); i++) {
        Debugger* dbg = fromJSObject(watchers[i]);

        // We disallow resumption values from onNewGlobalObject hooks, because we
        // want the debugger hooks for global object creation to be infallible.
        // But if an onNewGlobalObject hook throws, and the uncaughtExceptionHook
        // decides to raise an error, we want to at least avoid invoking the rest
        // of the onNewGlobalObject handlers in the list (not for any super
        // compelling reason, just because it seems like the right thing to do).
        // So we ignore whatever comes out in |value|, but break out of the loop
        // if a non-success trap status is returned.
        if (dbg->observesNewGlobalObject()) {
            status = dbg->fireNewGlobalObject(cx, global, &value);
            if (status != JSTRAP_CONTINUE && status != JSTRAP_RETURN)
                break;
        }
    }
    MOZ_ASSERT(!cx->isExceptionPending());
}

/* static */ bool
Debugger::slowPathOnLogAllocationSite(JSContext* cx, HandleObject obj, HandleSavedFrame frame,
                                      double when, GlobalObject::DebuggerVector& dbgs)
{
    MOZ_ASSERT(!dbgs.empty());
    mozilla::DebugOnly<Debugger**> begin = dbgs.begin();

    for (Debugger** dbgp = dbgs.begin(); dbgp < dbgs.end(); dbgp++) {
        // The set of debuggers had better not change while we're iterating,
        // such that the vector gets reallocated.
        MOZ_ASSERT(dbgs.begin() == begin);

        if ((*dbgp)->trackingAllocationSites &&
            (*dbgp)->enabled &&
            !(*dbgp)->appendAllocationSite(cx, obj, frame, when))
        {
            return false;
        }
    }

    return true;
}

/* static */ void
Debugger::slowPathOnIonCompilation(JSContext* cx, Handle<ScriptVector> scripts, LSprinter& graph)
{
    JSTrapStatus status = dispatchHook(
        cx,
        [](Debugger* dbg) -> bool { return dbg->getHook(OnIonCompilation); },
        [&](Debugger* dbg) -> JSTrapStatus {
            (void) dbg->fireOnIonCompilationHook(cx, scripts, graph);
            return JSTRAP_CONTINUE;
        });

    if (status == JSTRAP_ERROR) {
        cx->clearPendingException();
        return;
    }

    MOZ_ASSERT(status == JSTRAP_CONTINUE);
}

bool
Debugger::isDebuggee(const JSCompartment* compartment) const
{
    MOZ_ASSERT(compartment);
    return compartment->isDebuggee() && debuggees.has(compartment->maybeGlobal());
}

Debugger::TenurePromotionsLogEntry::TenurePromotionsLogEntry(JSRuntime* rt, JSObject& obj, double when)
  : className(obj.getClass()->name),
    when(when),
    frame(getObjectAllocationSite(obj)),
    size(JS::ubi::Node(&obj).size(rt->debuggerMallocSizeOf))
{ }


void
Debugger::logTenurePromotion(JSRuntime* rt, JSObject& obj, double when)
{
    if (!tenurePromotionsLog.emplaceBack(rt, obj, when))
        CrashAtUnhandlableOOM("Debugger::logTenurePromotion");

    if (tenurePromotionsLog.length() > maxTenurePromotionsLogLength) {
        if (!tenurePromotionsLog.popFront())
            CrashAtUnhandlableOOM("Debugger::logTenurePromotion");
        MOZ_ASSERT(tenurePromotionsLog.length() == maxTenurePromotionsLogLength);
        tenurePromotionsLogOverflowed = true;
    }
}

bool
Debugger::appendAllocationSite(JSContext* cx, HandleObject obj, HandleSavedFrame frame,
                               double when)
{
    MOZ_ASSERT(trackingAllocationSites);

    AutoCompartment ac(cx, object);
    RootedObject wrappedFrame(cx, frame);
    if (!cx->compartment()->wrap(cx, &wrappedFrame))
        return false;

    RootedAtom ctorName(cx);
    {
        AutoCompartment ac(cx, obj);
        if (!obj->constructorDisplayAtom(cx, &ctorName))
            return false;
    }

    auto className = obj->getClass()->name;
    auto size = JS::ubi::Node(obj.get()).size(cx->runtime()->debuggerMallocSizeOf);
    auto inNursery = gc::IsInsideNursery(obj);

    if (!allocationsLog.emplaceBack(wrappedFrame, when, className, ctorName, size, inNursery)) {
        ReportOutOfMemory(cx);
        return false;
    }

    if (allocationsLog.length() > maxAllocationsLogLength) {
        if (!allocationsLog.popFront()) {
            ReportOutOfMemory(cx);
            return false;
        }
        MOZ_ASSERT(allocationsLog.length() == maxAllocationsLogLength);
        allocationsLogOverflowed = true;
    }

    return true;
}

JSTrapStatus
Debugger::firePromiseHook(JSContext* cx, Hook hook, HandleObject promise, MutableHandleValue vp)
{
    MOZ_ASSERT(hook == OnNewPromise || hook == OnPromiseSettled);

    RootedObject hookObj(cx, getHook(hook));
    MOZ_ASSERT(hookObj);
    MOZ_ASSERT(hookObj->isCallable());

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, object);

    RootedValue dbgObj(cx, ObjectValue(*promise));
    if (!wrapDebuggeeValue(cx, &dbgObj))
        return handleUncaughtException(ac, false);

    // Like onNewGlobalObject, the Promise hooks are infallible and the comments
    // in |Debugger::fireNewGlobalObject| apply here as well.

    RootedValue rv(cx);
    bool ok = Invoke(cx, ObjectValue(*object), ObjectValue(*hookObj), 1, dbgObj.address(), &rv);
    if (ok && !rv.isUndefined()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                             JSMSG_DEBUG_RESUMPTION_VALUE_DISALLOWED);
        ok = false;
    }

    JSTrapStatus status = ok ? JSTRAP_CONTINUE
                             : handleUncaughtException(ac, vp, true);
    MOZ_ASSERT(!cx->isExceptionPending());
    return status;
}

/* static */ void
Debugger::slowPathPromiseHook(JSContext* cx, Hook hook, HandleObject promise)
{
    MOZ_ASSERT(hook == OnNewPromise || hook == OnPromiseSettled);
    RootedValue rval(cx);

    JSTrapStatus status = dispatchHook(
        cx,
        [hook](Debugger* dbg) -> bool { return dbg->getHook(hook); },
        [&](Debugger* dbg) -> JSTrapStatus {
            (void) dbg->firePromiseHook(cx, hook, promise, &rval);
            return JSTRAP_CONTINUE;
        });

    if (status == JSTRAP_ERROR) {
        // The dispatch hook function might fail to append into the list of
        // Debuggers which are watching for the hook.
        cx->clearPendingException();
        return;
    }

    // Promise hooks are infallible and we ignore errors from uncaught
    // exceptions by design.
    MOZ_ASSERT(status == JSTRAP_CONTINUE);
}


/*** Debugger code invalidation for observing execution ******************************************/

class MOZ_RAII ExecutionObservableCompartments : public Debugger::ExecutionObservableSet
{
    HashSet<JSCompartment*> compartments_;
    HashSet<Zone*> zones_;

  public:
    explicit ExecutionObservableCompartments(JSContext* cx
                                             MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : compartments_(cx),
        zones_(cx)
    {
        MOZ_GUARD_OBJECT_NOTIFIER_INIT;
    }

    bool init() { return compartments_.init() && zones_.init(); }
    bool add(JSCompartment* comp) { return compartments_.put(comp) && zones_.put(comp->zone()); }

    typedef HashSet<JSCompartment*>::Range CompartmentRange;
    const HashSet<JSCompartment*>* compartments() const { return &compartments_; }

    const HashSet<Zone*>* zones() const { return &zones_; }
    bool shouldRecompileOrInvalidate(JSScript* script) const {
        return script->hasBaselineScript() && compartments_.has(script->compartment());
    }
    bool shouldMarkAsDebuggee(ScriptFrameIter& iter) const {
        // AbstractFramePtr can't refer to non-remateralized Ion frames, so if
        // iter refers to one such, we know we don't match.
        return iter.hasUsableAbstractFramePtr() && compartments_.has(iter.compartment());
    }

    MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

// Given a particular AbstractFramePtr F that has become observable, this
// represents the stack frames that need to be bailed out or marked as
// debuggees, and the scripts that need to be recompiled, taking inlining into
// account.
class MOZ_RAII ExecutionObservableFrame : public Debugger::ExecutionObservableSet
{
    AbstractFramePtr frame_;

  public:
    explicit ExecutionObservableFrame(AbstractFramePtr frame
                                      MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : frame_(frame)
    {
        MOZ_GUARD_OBJECT_NOTIFIER_INIT;
    }

    Zone* singleZone() const {
        // We never inline across compartments, let alone across zones, so
        // frames_'s script's zone is the only one of interest.
        return frame_.script()->compartment()->zone();
    }

    JSScript* singleScriptForZoneInvalidation() const {
        MOZ_CRASH("ExecutionObservableFrame shouldn't need zone-wide invalidation.");
        return nullptr;
    }

    bool shouldRecompileOrInvalidate(JSScript* script) const {
        // Normally, *this represents exactly one script: the one frame_ is
        // running.
        //
        // However, debug-mode OSR uses *this for both invalidating Ion frames,
        // and recompiling the Baseline scripts that those Ion frames will bail
        // out into. Suppose frame_ is an inline frame, executing a copy of its
        // JSScript, S_inner, that has been inlined into the IonScript of some
        // other JSScript, S_outer. We must match S_outer, to decide which Ion
        // frame to invalidate; and we must match S_inner, to decide which
        // Baseline script to recompile.
        //
        // Note that this does not, by design, invalidate *all* inliners of
        // frame_.script(), as only frame_ is made observable, not
        // frame_.script().
        if (!script->hasBaselineScript())
            return false;

        if (script == frame_.script())
            return true;

        return frame_.isRematerializedFrame() &&
               script == frame_.asRematerializedFrame()->outerScript();
    }

    bool shouldMarkAsDebuggee(ScriptFrameIter& iter) const {
        // AbstractFramePtr can't refer to non-remateralized Ion frames, so if
        // iter refers to one such, we know we don't match.
        //
        // We never use this 'has' overload for frame invalidation, only for
        // frame debuggee marking; so this overload doesn't need a parallel to
        // the just-so inlining logic above.
        return iter.hasUsableAbstractFramePtr() && iter.abstractFramePtr() == frame_;
    }

    MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

class MOZ_RAII ExecutionObservableScript : public Debugger::ExecutionObservableSet
{
    RootedScript script_;

  public:
    ExecutionObservableScript(JSContext* cx, JSScript* script
                              MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : script_(cx, script)
    {
        MOZ_GUARD_OBJECT_NOTIFIER_INIT;
    }

    Zone* singleZone() const { return script_->compartment()->zone(); }
    JSScript* singleScriptForZoneInvalidation() const { return script_; }
    bool shouldRecompileOrInvalidate(JSScript* script) const {
        return script->hasBaselineScript() && script == script_;
    }
    bool shouldMarkAsDebuggee(ScriptFrameIter& iter) const {
        // AbstractFramePtr can't refer to non-remateralized Ion frames, and
        // while a non-rematerialized Ion frame may indeed be running script_,
        // we cannot mark them as debuggees until they bail out.
        //
        // Upon bailing out, any newly constructed Baseline frames that came
        // from Ion frames with scripts that are isDebuggee() is marked as
        // debuggee. This is correct in that the only other way a frame may be
        // marked as debuggee is via Debugger.Frame reflection, which would
        // have rematerialized any Ion frames.
        return iter.hasUsableAbstractFramePtr() && iter.abstractFramePtr().script() == script_;
    }

    MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

/* static */ bool
Debugger::updateExecutionObservabilityOfFrames(JSContext* cx, const ExecutionObservableSet& obs,
                                               IsObserving observing)
{
    AutoSuppressProfilerSampling suppressProfilerSampling(cx);

    {
        jit::JitContext jctx(cx, nullptr);
        if (!jit::RecompileOnStackBaselineScriptsForDebugMode(cx, obs, observing)) {
            ReportOutOfMemory(cx);
            return false;
        }
    }

    AbstractFramePtr oldestEnabledFrame;
    for (ScriptFrameIter iter(cx, ScriptFrameIter::ALL_CONTEXTS,
                              ScriptFrameIter::GO_THROUGH_SAVED);
         !iter.done();
         ++iter)
    {
        if (obs.shouldMarkAsDebuggee(iter)) {
            if (observing) {
                if (!iter.abstractFramePtr().isDebuggee()) {
                    oldestEnabledFrame = iter.abstractFramePtr();
                    oldestEnabledFrame.setIsDebuggee();
                }
            } else {
#ifdef DEBUG
                // Debugger.Frame lifetimes are managed by the debug epilogue,
                // so in general it's unsafe to unmark a frame if it has a
                // Debugger.Frame associated with it.
                FrameRange r(iter.abstractFramePtr());
                MOZ_ASSERT(r.empty());
#endif
                iter.abstractFramePtr().unsetIsDebuggee();
            }
        }
    }

    // See comment in unsetPrevUpToDateUntil.
    if (oldestEnabledFrame) {
        AutoCompartment ac(cx, oldestEnabledFrame.compartment());
        DebugScopes::unsetPrevUpToDateUntil(cx, oldestEnabledFrame);
    }

    return true;
}

static inline void
MarkBaselineScriptActiveIfObservable(JSScript* script, const Debugger::ExecutionObservableSet& obs)
{
    if (obs.shouldRecompileOrInvalidate(script))
        script->baselineScript()->setActive();
}

static bool
AppendAndInvalidateScript(JSContext* cx, Zone* zone, JSScript* script, Vector<JSScript*>& scripts)
{
    // Enter the script's compartment as addPendingRecompile attempts to
    // cancel off-thread compilations, whose books are kept on the
    // script's compartment.
    MOZ_ASSERT(script->compartment()->zone() == zone);
    AutoCompartment ac(cx, script->compartment());
    zone->types.addPendingRecompile(cx, script);
    return scripts.append(script);
}

static bool
UpdateExecutionObservabilityOfScriptsInZone(JSContext* cx, Zone* zone,
                                            const Debugger::ExecutionObservableSet& obs,
                                            Debugger::IsObserving observing)
{
    using namespace js::jit;

    // See note in js::ReleaseAllJITCode.
    cx->runtime()->gc.evictNursery();

    AutoSuppressProfilerSampling suppressProfilerSampling(cx);

    JSRuntime* rt = cx->runtime();
    FreeOp* fop = cx->runtime()->defaultFreeOp();

    // Mark active baseline scripts in the observable set so that they don't
    // get discarded. They will be recompiled.
    for (JitActivationIterator actIter(rt); !actIter.done(); ++actIter) {
        if (actIter->compartment()->zone() != zone)
            continue;

        for (JitFrameIterator iter(actIter); !iter.done(); ++iter) {
            switch (iter.type()) {
              case JitFrame_BaselineJS:
                MarkBaselineScriptActiveIfObservable(iter.script(), obs);
                break;
              case JitFrame_IonJS:
                MarkBaselineScriptActiveIfObservable(iter.script(), obs);
                for (InlineFrameIterator inlineIter(rt, &iter); inlineIter.more(); ++inlineIter)
                    MarkBaselineScriptActiveIfObservable(inlineIter.script(), obs);
                break;
              default:;
            }
        }
    }

    Vector<JSScript*> scripts(cx);

    // Iterate through observable scripts, invalidating their Ion scripts and
    // appending them to a vector for discarding their baseline scripts later.
    {
        AutoEnterAnalysis enter(fop, zone);
        if (JSScript* script = obs.singleScriptForZoneInvalidation()) {
            if (obs.shouldRecompileOrInvalidate(script)) {
                if (!AppendAndInvalidateScript(cx, zone, script, scripts))
                    return false;
            }
        } else {
            for (gc::ZoneCellIter iter(zone, gc::AllocKind::SCRIPT); !iter.done(); iter.next()) {
                JSScript* script = iter.get<JSScript>();
                if (obs.shouldRecompileOrInvalidate(script) &&
                    !gc::IsAboutToBeFinalizedUnbarriered(&script))
                {
                    if (!AppendAndInvalidateScript(cx, zone, script, scripts))
                        return false;
                }
            }
        }
    }

    // Iterate through the scripts again and finish discarding
    // BaselineScripts. This must be done as a separate phase as we can only
    // discard the BaselineScript on scripts that have no IonScript.
    for (size_t i = 0; i < scripts.length(); i++) {
        MOZ_ASSERT_IF(scripts[i]->isDebuggee(), observing);
        FinishDiscardBaselineScript(fop, scripts[i]);
    }

    return true;
}

/* static */ bool
Debugger::updateExecutionObservabilityOfScripts(JSContext* cx, const ExecutionObservableSet& obs,
                                                IsObserving observing)
{
    if (Zone* zone = obs.singleZone())
        return UpdateExecutionObservabilityOfScriptsInZone(cx, zone, obs, observing);

    typedef ExecutionObservableSet::ZoneRange ZoneRange;
    for (ZoneRange r = obs.zones()->all(); !r.empty(); r.popFront()) {
        if (!UpdateExecutionObservabilityOfScriptsInZone(cx, r.front(), obs, observing))
            return false;
    }

    return true;
}

/* static */ bool
Debugger::updateExecutionObservability(JSContext* cx, ExecutionObservableSet& obs,
                                       IsObserving observing)
{
    if (!obs.singleZone() && obs.zones()->empty())
        return true;

    // Invalidate scripts first so we can set the needsArgsObj flag on scripts
    // before patching frames.
    return updateExecutionObservabilityOfScripts(cx, obs, observing) &&
           updateExecutionObservabilityOfFrames(cx, obs, observing);
}

/* static */ bool
Debugger::ensureExecutionObservabilityOfScript(JSContext* cx, JSScript* script)
{
    if (script->isDebuggee())
        return true;
    ExecutionObservableScript obs(cx, script);
    return updateExecutionObservability(cx, obs, Observing);
}

/* static */ bool
Debugger::ensureExecutionObservabilityOfOsrFrame(JSContext* cx, InterpreterFrame* frame)
{
    MOZ_ASSERT(frame->isDebuggee());
    if (frame->script()->hasBaselineScript() &&
        frame->script()->baselineScript()->hasDebugInstrumentation())
    {
        return true;
    }
    ExecutionObservableFrame obs(frame);
    return updateExecutionObservabilityOfFrames(cx, obs, Observing);
}

/* static */ bool
Debugger::ensureExecutionObservabilityOfFrame(JSContext* cx, AbstractFramePtr frame)
{
    MOZ_ASSERT_IF(frame.script()->isDebuggee(), frame.isDebuggee());
    if (frame.isDebuggee())
        return true;
    ExecutionObservableFrame obs(frame);
    return updateExecutionObservabilityOfFrames(cx, obs, Observing);
}

/* static */ bool
Debugger::ensureExecutionObservabilityOfCompartment(JSContext* cx, JSCompartment* comp)
{
    if (comp->debuggerObservesAllExecution())
        return true;
    ExecutionObservableCompartments obs(cx);
    if (!obs.init() || !obs.add(comp))
        return false;
    comp->updateDebuggerObservesAllExecution();
    return updateExecutionObservability(cx, obs, Observing);
}

/* static */ bool
Debugger::hookObservesAllExecution(Hook which)
{
    return which == OnEnterFrame;
}

Debugger::IsObserving
Debugger::observesAllExecution() const
{
    if (enabled && !!getHook(OnEnterFrame))
        return Observing;
    return NotObserving;
}

Debugger::IsObserving
Debugger::observesAsmJS() const
{
    if (enabled && !allowUnobservedAsmJS)
        return Observing;
    return NotObserving;
}

Debugger::IsObserving
Debugger::observesCoverage() const
{
    if (enabled && collectCoverageInfo)
        return Observing;
    return NotObserving;
}

// Toggle whether this Debugger's debuggees observe all execution. This is
// called when a hook that observes all execution is set or unset. See
// hookObservesAllExecution.
bool
Debugger::updateObservesAllExecutionOnDebuggees(JSContext* cx, IsObserving observing)
{
    ExecutionObservableCompartments obs(cx);
    if (!obs.init())
        return false;

    for (WeakGlobalObjectSet::Range r = debuggees.all(); !r.empty(); r.popFront()) {
        GlobalObject* global = r.front();
        JSCompartment* comp = global->compartment();

        if (comp->debuggerObservesAllExecution() == observing)
            continue;

        // It's expensive to eagerly invalidate and recompile a compartment,
        // so add the compartment to the set only if we are observing.
        if (observing && !obs.add(comp))
            return false;

        comp->updateDebuggerObservesAllExecution();
    }

    return updateExecutionObservability(cx, obs, observing);
}

bool
Debugger::updateObservesCoverageOnDebuggees(JSContext* cx, IsObserving observing)
{
    ExecutionObservableCompartments obs(cx);
    if (!obs.init())
        return false;

    for (WeakGlobalObjectSet::Range r = debuggees.all(); !r.empty(); r.popFront()) {
        GlobalObject* global = r.front();
        JSCompartment* comp = global->compartment();

        if (comp->debuggerObservesCoverage() == observing)
            continue;

        // Invalidate and recompile a compartment to add or remove PCCounts
        // increments. We have to eagerly invalidate, as otherwise we might have
        // dangling pointers to freed PCCounts.
        if (!obs.add(comp))
            return false;
    }

    // If any frame on the stack belongs to the debuggee, then we cannot update
    // the ScriptCounts, because this would imply to invalidate a Debugger.Frame
    // to recompile it with/without ScriptCount support.
    for (ScriptFrameIter iter(cx, ScriptFrameIter::ALL_CONTEXTS,
                              ScriptFrameIter::GO_THROUGH_SAVED);
         !iter.done();
         ++iter)
    {
        if (obs.shouldMarkAsDebuggee(iter)) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_NOT_IDLE);
            return false;
        }
    }

    if (!updateExecutionObservability(cx, obs, observing))
        return false;

    // All compartments can safely be toggled, and all scripts will be
    // recompiled. Thus we can update each compartment accordingly.
    typedef ExecutionObservableCompartments::CompartmentRange CompartmentRange;
    for (CompartmentRange r = obs.compartments()->all(); !r.empty(); r.popFront())
        r.front()->updateDebuggerObservesCoverage();

    return true;
}

void
Debugger::updateObservesAsmJSOnDebuggees(IsObserving observing)
{
    for (WeakGlobalObjectSet::Range r = debuggees.all(); !r.empty(); r.popFront()) {
        GlobalObject* global = r.front();
        JSCompartment* comp = global->compartment();

        if (comp->debuggerObservesAsmJS() == observing)
            continue;

        comp->updateDebuggerObservesAsmJS();
    }
}


/*** Allocations Tracking *************************************************************************/

/* static */ bool
Debugger::cannotTrackAllocations(const GlobalObject& global)
{
    auto existingCallback = global.compartment()->getObjectMetadataCallback();
    return existingCallback && existingCallback != SavedStacksMetadataCallback;
}

/* static */ bool
Debugger::isObservedByDebuggerTrackingAllocations(const GlobalObject& debuggee)
{
    if (auto* v = debuggee.getDebuggers()) {
        Debugger** p;
        for (p = v->begin(); p != v->end(); p++) {
            if ((*p)->trackingAllocationSites) {
                return true;
            }
        }
    }

    return false;
}

/* static */ bool
Debugger::addAllocationsTracking(JSContext* cx, GlobalObject& debuggee)
{
    // Precondition: the given global object is being observed by at least one
    // Debugger that is tracking allocations.
    MOZ_ASSERT(isObservedByDebuggerTrackingAllocations(debuggee));

    if (Debugger::cannotTrackAllocations(debuggee)) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                             JSMSG_OBJECT_METADATA_CALLBACK_ALREADY_SET);
        return false;
    }

    debuggee.compartment()->setObjectMetadataCallback(SavedStacksMetadataCallback);
    return true;
}

/* static */ void
Debugger::removeAllocationsTracking(GlobalObject& global)
{
    // If there are still Debuggers that are observing allocations, we cannot
    // remove the metadata callback yet.
    if (isObservedByDebuggerTrackingAllocations(global))
        return;

    global.compartment()->forgetObjectMetadataCallback();
}

bool
Debugger::addAllocationsTrackingForAllDebuggees(JSContext* cx)
{
    MOZ_ASSERT(trackingAllocationSites);

    // We don't want to end up in a state where we added allocations
    // tracking to some of our debuggees, but failed to do so for
    // others. Before attempting to start tracking allocations in *any* of
    // our debuggees, ensure that we will be able to track allocations for
    // *all* of our debuggees.
    for (WeakGlobalObjectSet::Range r = debuggees.all(); !r.empty(); r.popFront()) {
        if (Debugger::cannotTrackAllocations(*r.front().get())) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                                 JSMSG_OBJECT_METADATA_CALLBACK_ALREADY_SET);
            return false;
        }
    }

    for (WeakGlobalObjectSet::Range r = debuggees.all(); !r.empty(); r.popFront()) {
        // This should always succeed, since we already checked for the
        // error case above.
        MOZ_ALWAYS_TRUE(Debugger::addAllocationsTracking(cx, *r.front().get()));
    }

    return true;
}

void
Debugger::removeAllocationsTrackingForAllDebuggees()
{
    for (WeakGlobalObjectSet::Range r = debuggees.all(); !r.empty(); r.popFront()) {
        Debugger::removeAllocationsTracking(*r.front().get());
    }
    allocationsLog.clear();
}



/*** Debugger JSObjects **************************************************************************/

void
Debugger::markCrossCompartmentEdges(JSTracer* trc)
{
    objects.markCrossCompartmentEdges<DebuggerObject_trace>(trc);
    environments.markCrossCompartmentEdges<DebuggerEnv_trace>(trc);
    scripts.markCrossCompartmentEdges<DebuggerScript_trace>(trc);
    sources.markCrossCompartmentEdges<DebuggerSource_trace>(trc);

    // Because we don't have access to a `cx` inside
    // `Debugger::logTenurePromotion`, we can't hold onto CCWs inside the log,
    // and instead have unwrapped cross-compartment edges. We need to be sure to
    // mark those here.
    TenurePromotionsLog::trace(&tenurePromotionsLog, trc);
}

/*
 * Ordinarily, WeakMap keys and values are marked because at some point it was
 * discovered that the WeakMap was live; that is, some object containing the
 * WeakMap was marked during mark phase.
 *
 * However, during zone GC, we have to do something about cross-compartment
 * edges in non-GC'd compartments. Since the source may be live, we
 * conservatively assume it is and mark the edge.
 *
 * Each Debugger object keeps four cross-compartment WeakMaps: objects, scripts,
 * script source objects, and environments. They have the property that all
 * their values are in the same compartment as the Debugger object, but we have
 * to mark the keys and the private pointer in the wrapper object.
 *
 * We must scan all Debugger objects regardless of whether they *currently* have
 * any debuggees in a compartment being GC'd, because the WeakMap entries
 * persist even when debuggees are removed.
 *
 * This happens during the initial mark phase, not iterative marking, because
 * all the edges being reported here are strong references.
 *
 * This method is also used during compacting GC to update cross compartment
 * pointers in zones that are not currently being compacted.
 */
/* static */ void
Debugger::markIncomingCrossCompartmentEdges(JSTracer* trc)
{
    JSRuntime* rt = trc->runtime();
    gc::State state = rt->gc.state();
    MOZ_ASSERT(state == gc::MARK_ROOTS || state == gc::COMPACT);

    for (Debugger* dbg = rt->debuggerList.getFirst(); dbg; dbg = dbg->getNext()) {
        Zone* zone = dbg->object->zone();
        if ((state == gc::MARK_ROOTS && !zone->isCollecting()) ||
            (state == gc::COMPACT && !zone->isGCCompacting()))
        {
            dbg->markCrossCompartmentEdges(trc);
        }
    }
}

/*
 * This method has two tasks:
 *   1. Mark Debugger objects that are unreachable except for debugger hooks that
 *      may yet be called.
 *   2. Mark breakpoint handlers.
 *
 * This happens during the iterative part of the GC mark phase. This method
 * returns true if it has to mark anything; GC calls it repeatedly until it
 * returns false.
 */
/* static */ bool
Debugger::markAllIteratively(GCMarker* trc)
{
    bool markedAny = false;

    /*
     * Find all Debugger objects in danger of GC. This code is a little
     * convoluted since the easiest way to find them is via their debuggees.
     */
    JSRuntime* rt = trc->runtime();
    for (CompartmentsIter c(rt, SkipAtoms); !c.done(); c.next()) {
        if (c->isDebuggee()) {
            GlobalObject* global = c->maybeGlobal();
            if (!IsMarkedUnbarriered(&global))
                continue;

            /*
             * Every debuggee has at least one debugger, so in this case
             * getDebuggers can't return nullptr.
             */
            const GlobalObject::DebuggerVector* debuggers = global->getDebuggers();
            MOZ_ASSERT(debuggers);
            for (Debugger * const* p = debuggers->begin(); p != debuggers->end(); p++) {
                Debugger* dbg = *p;

                /*
                 * dbg is a Debugger with at least one debuggee. Check three things:
                 *   - dbg is actually in a compartment that is being marked
                 *   - it isn't already marked
                 *   - it actually has hooks that might be called
                 */
                HeapPtrNativeObject& dbgobj = dbg->toJSObjectRef();
                if (!dbgobj->zone()->isGCMarking())
                    continue;

                bool dbgMarked = IsMarked(&dbgobj);
                if (!dbgMarked && dbg->hasAnyLiveHooks()) {
                    /*
                     * obj could be reachable only via its live, enabled
                     * debugger hooks, which may yet be called.
                     */
                    TraceEdge(trc, &dbgobj, "enabled Debugger");
                    markedAny = true;
                    dbgMarked = true;
                }

                if (dbgMarked) {
                    /* Search for breakpoints to mark. */
                    for (Breakpoint* bp = dbg->firstBreakpoint(); bp; bp = bp->nextInDebugger()) {
                        if (IsMarkedUnbarriered(&bp->site->script)) {
                            /*
                             * The debugger and the script are both live.
                             * Therefore the breakpoint handler is live.
                             */
                            if (!IsMarked(&bp->getHandlerRef())) {
                                TraceEdge(trc, &bp->getHandlerRef(), "breakpoint handler");
                                markedAny = true;
                            }
                        }
                    }
                }
            }
        }
    }
    return markedAny;
}

/*
 * Mark all debugger-owned GC things unconditionally. This is used by the minor
 * GC: the minor GC cannot apply the weak constraints of the full GC because it
 * visits only part of the heap.
 */
/* static */ void
Debugger::markAll(JSTracer* trc)
{
    JSRuntime* rt = trc->runtime();
    for (Debugger* dbg = rt->debuggerList.getFirst(); dbg; dbg = dbg->getNext()) {
        WeakGlobalObjectSet& debuggees = dbg->debuggees;
        for (WeakGlobalObjectSet::Enum e(debuggees); !e.empty(); e.popFront()) {
            GlobalObject* global = e.front();
            TraceManuallyBarrieredEdge(trc, &global, "Global Object");
            if (global != e.front())
                e.rekeyFront(ReadBarrieredGlobalObject(global));
        }

        HeapPtrNativeObject& dbgobj = dbg->toJSObjectRef();
        TraceEdge(trc, &dbgobj, "Debugger Object");

        dbg->scripts.trace(trc);
        dbg->sources.trace(trc);
        dbg->objects.trace(trc);
        dbg->environments.trace(trc);

        for (Breakpoint* bp = dbg->firstBreakpoint(); bp; bp = bp->nextInDebugger()) {
            TraceManuallyBarrieredEdge(trc, &bp->site->script, "breakpoint script");
            TraceEdge(trc, &bp->getHandlerRef(), "breakpoint handler");
        }
    }
}

/* static */ void
Debugger::traceObject(JSTracer* trc, JSObject* obj)
{
    if (Debugger* dbg = Debugger::fromJSObject(obj))
        dbg->trace(trc);
}

void
Debugger::trace(JSTracer* trc)
{
    if (uncaughtExceptionHook)
        TraceEdge(trc, &uncaughtExceptionHook, "hooks");

    /*
     * Mark Debugger.Frame objects. These are all reachable from JS, because the
     * corresponding JS frames are still on the stack.
     *
     * (Once we support generator frames properly, we will need
     * weakly-referenced Debugger.Frame objects as well, for suspended generator
     * frames.)
     */
    for (FrameMap::Range r = frames.all(); !r.empty(); r.popFront()) {
        RelocatablePtrNativeObject& frameobj = r.front().value();
        MOZ_ASSERT(MaybeForwarded(frameobj.get())->getPrivate());
        TraceEdge(trc, &frameobj, "live Debugger.Frame");
    }

    AllocationsLog::trace(&allocationsLog, trc);
    TenurePromotionsLog::trace(&tenurePromotionsLog, trc);

    /* Trace the weak map from JSScript instances to Debugger.Script objects. */
    scripts.trace(trc);

    /* Trace the referent ->Debugger.Source weak map */
    sources.trace(trc);

    /* Trace the referent -> Debugger.Object weak map. */
    objects.trace(trc);

    /* Trace the referent -> Debugger.Environment weak map. */
    environments.trace(trc);
}

/* static */ void
Debugger::sweepAll(FreeOp* fop)
{
    JSRuntime* rt = fop->runtime();

    for (Debugger* dbg = rt->debuggerList.getFirst(); dbg; dbg = dbg->getNext()) {
        if (IsAboutToBeFinalized(&dbg->object)) {
            /*
             * dbg is being GC'd. Detach it from its debuggees. The debuggee
             * might be GC'd too. Since detaching requires access to both
             * objects, this must be done before finalize time.
             */
            for (WeakGlobalObjectSet::Enum e(dbg->debuggees); !e.empty(); e.popFront())
                dbg->removeDebuggeeGlobal(fop, e.front(), &e);
        }
    }
}

/* static */ void
Debugger::detachAllDebuggersFromGlobal(FreeOp* fop, GlobalObject* global)
{
    const GlobalObject::DebuggerVector* debuggers = global->getDebuggers();
    MOZ_ASSERT(!debuggers->empty());
    while (!debuggers->empty())
        debuggers->back()->removeDebuggeeGlobal(fop, global, nullptr);
}

/* static */ void
Debugger::findZoneEdges(Zone* zone, js::gc::ComponentFinder<Zone>& finder)
{
    /*
     * For debugger cross compartment wrappers, add edges in the opposite
     * direction to those already added by JSCompartment::findOutgoingEdges.
     * This ensure that debuggers and their debuggees are finalized in the same
     * group.
     */
    for (Debugger* dbg = zone->runtimeFromMainThread()->debuggerList.getFirst();
         dbg;
         dbg = dbg->getNext())
    {
        Zone* w = dbg->object->zone();
        if (w == zone || !w->isGCMarking())
            continue;
        if (dbg->debuggeeZones.has(zone) ||
            dbg->scripts.hasKeyInZone(zone) ||
            dbg->sources.hasKeyInZone(zone) ||
            dbg->objects.hasKeyInZone(zone) ||
            dbg->environments.hasKeyInZone(zone))
        {
            finder.addEdgeTo(w);
        }
    }
}

/* static */ void
Debugger::finalize(FreeOp* fop, JSObject* obj)
{
    Debugger* dbg = fromJSObject(obj);
    if (!dbg)
        return;
    fop->delete_(dbg);
}

const Class Debugger::jsclass = {
    "Debugger",
    JSCLASS_HAS_PRIVATE |
    JSCLASS_HAS_RESERVED_SLOTS(JSSLOT_DEBUG_COUNT),
    nullptr, nullptr, nullptr, nullptr, nullptr,
    nullptr, nullptr, nullptr, Debugger::finalize,
    nullptr,              /* call        */
    nullptr,              /* hasInstance */
    nullptr,              /* construct   */
    Debugger::traceObject
};

/* static */ Debugger*
Debugger::fromThisValue(JSContext* cx, const CallArgs& args, const char* fnname)
{
    JSObject* thisobj = NonNullObject(cx, args.thisv());
    if (!thisobj)
        return nullptr;
    if (thisobj->getClass() != &Debugger::jsclass) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger", fnname, thisobj->getClass()->name);
        return nullptr;
    }

    /*
     * Forbid Debugger.prototype, which is of the Debugger JSClass but isn't
     * really a Debugger object. The prototype object is distinguished by
     * having a nullptr private value.
     */
    Debugger* dbg = fromJSObject(thisobj);
    if (!dbg) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger", fnname, "prototype object");
    }
    return dbg;
}

#define THIS_DEBUGGER(cx, argc, vp, fnname, args, dbg)                       \
    CallArgs args = CallArgsFromVp(argc, vp);                                \
    Debugger* dbg = Debugger::fromThisValue(cx, args, fnname);               \
    if (!dbg)                                                                \
        return false

/* static */ bool
Debugger::getEnabled(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "get enabled", args, dbg);
    args.rval().setBoolean(dbg->enabled);
    return true;
}

/* static */ bool
Debugger::setEnabled(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "set enabled", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.set enabled", 1))
        return false;

    bool wasEnabled = dbg->enabled;
    dbg->enabled = ToBoolean(args[0]);

    if (wasEnabled != dbg->enabled) {
        if (dbg->trackingAllocationSites) {
            if (wasEnabled) {
                dbg->removeAllocationsTrackingForAllDebuggees();
            } else {
                if (!dbg->addAllocationsTrackingForAllDebuggees(cx)) {
                    dbg->enabled = false;
                    return false;
                }
            }
        }

        for (Breakpoint* bp = dbg->firstBreakpoint(); bp; bp = bp->nextInDebugger()) {
            if (!wasEnabled)
                bp->site->inc(cx->runtime()->defaultFreeOp());
            else
                bp->site->dec(cx->runtime()->defaultFreeOp());
        }

        /*
         * Add or remove ourselves from the runtime's list of Debuggers
         * that care about new globals.
         */
        if (dbg->getHook(OnNewGlobalObject)) {
            if (!wasEnabled) {
                /* If we were not enabled, the link should be a singleton list. */
                MOZ_ASSERT(JS_CLIST_IS_EMPTY(&dbg->onNewGlobalObjectWatchersLink));
                JS_APPEND_LINK(&dbg->onNewGlobalObjectWatchersLink,
                               &cx->runtime()->onNewGlobalObjectWatchers);
            } else {
                /* If we were enabled, the link should be inserted in the list. */
                MOZ_ASSERT(!JS_CLIST_IS_EMPTY(&dbg->onNewGlobalObjectWatchersLink));
                JS_REMOVE_AND_INIT_LINK(&dbg->onNewGlobalObjectWatchersLink);
            }
        }

        // Ensure the compartment is observable if we are re-enabling a
        // Debugger with hooks that observe all execution.
        if (!dbg->updateObservesAllExecutionOnDebuggees(cx, dbg->observesAllExecution()))
            return false;

        // Note: To toogle code coverage, we currently need to have no live
        // stack frame, thus the coverage does not depend on the enabled flag.

        dbg->updateObservesAsmJSOnDebuggees(dbg->observesAsmJS());
    }

    args.rval().setUndefined();
    return true;
}

/* static */ bool
Debugger::getHookImpl(JSContext* cx, CallArgs& args, Debugger& dbg, Hook which)
{
    MOZ_ASSERT(which >= 0 && which < HookCount);
    args.rval().set(dbg.object->getReservedSlot(JSSLOT_DEBUG_HOOK_START + which));
    return true;
}

/* static */ bool
Debugger::setHookImpl(JSContext* cx, CallArgs& args, Debugger& dbg, Hook which)
{
    MOZ_ASSERT(which >= 0 && which < HookCount);
    if (!args.requireAtLeast(cx, "Debugger.setHook", 1))
        return false;
    if (args[0].isObject()) {
        if (!args[0].toObject().isCallable())
            return ReportIsNotFunction(cx, args[0], args.length() - 1);
    } else if (!args[0].isUndefined()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NOT_CALLABLE_OR_UNDEFINED);
        return false;
    }
    dbg.object->setReservedSlot(JSSLOT_DEBUG_HOOK_START + which, args[0]);
    if (hookObservesAllExecution(which)) {
        if (!dbg.updateObservesAllExecutionOnDebuggees(cx, dbg.observesAllExecution()))
            return false;
    }
    args.rval().setUndefined();
    return true;
}

/* static */ bool
Debugger::getOnDebuggerStatement(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(get onDebuggerStatement)", args, dbg);
    return getHookImpl(cx, args, *dbg, OnDebuggerStatement);
}

/* static */ bool
Debugger::setOnDebuggerStatement(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(set onDebuggerStatement)", args, dbg);
    return setHookImpl(cx, args, *dbg, OnDebuggerStatement);
}

/* static */ bool
Debugger::getOnExceptionUnwind(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(get onExceptionUnwind)", args, dbg);
    return getHookImpl(cx, args, *dbg, OnExceptionUnwind);
}

/* static */ bool
Debugger::setOnExceptionUnwind(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(set onExceptionUnwind)", args, dbg);
    return setHookImpl(cx, args, *dbg, OnExceptionUnwind);
}

/* static */ bool
Debugger::getOnNewScript(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(get onNewScript)", args, dbg);
    return getHookImpl(cx, args, *dbg, OnNewScript);
}

/* static */ bool
Debugger::setOnNewScript(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(set onNewScript)", args, dbg);
    return setHookImpl(cx, args, *dbg, OnNewScript);
}

/* static */ bool
Debugger::getOnNewPromise(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(get onNewPromise)", args, dbg);
    return getHookImpl(cx, args, *dbg, OnNewPromise);
}

/* static */ bool
Debugger::setOnNewPromise(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(set onNewPromise)", args, dbg);
    return setHookImpl(cx, args, *dbg, OnNewPromise);
}

/* static */ bool
Debugger::getOnPromiseSettled(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(get onPromiseSettled)", args, dbg);
    return getHookImpl(cx, args, *dbg, OnPromiseSettled);
}

/* static */ bool
Debugger::setOnPromiseSettled(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(set onPromiseSettled)", args, dbg);
    return setHookImpl(cx, args, *dbg, OnPromiseSettled);
}

/* static */ bool
Debugger::getOnEnterFrame(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(get onEnterFrame)", args, dbg);
    return getHookImpl(cx, args, *dbg, OnEnterFrame);
}

/* static */ bool
Debugger::setOnEnterFrame(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(set onEnterFrame)", args, dbg);
    return setHookImpl(cx, args, *dbg, OnEnterFrame);
}

/* static */ bool
Debugger::getOnNewGlobalObject(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(get onNewGlobalObject)", args, dbg);
    return getHookImpl(cx, args, *dbg, OnNewGlobalObject);
}

/* static */ bool
Debugger::setOnNewGlobalObject(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "setOnNewGlobalObject", args, dbg);
    RootedObject oldHook(cx, dbg->getHook(OnNewGlobalObject));

    if (!setHookImpl(cx, args, *dbg, OnNewGlobalObject))
        return false;

    /*
     * Add or remove ourselves from the runtime's list of Debuggers that
     * care about new globals.
     */
    if (dbg->enabled) {
        JSObject* newHook = dbg->getHook(OnNewGlobalObject);
        if (!oldHook && newHook) {
            /* If we didn't have a hook, the link should be a singleton list. */
            MOZ_ASSERT(JS_CLIST_IS_EMPTY(&dbg->onNewGlobalObjectWatchersLink));
            JS_APPEND_LINK(&dbg->onNewGlobalObjectWatchersLink,
                           &cx->runtime()->onNewGlobalObjectWatchers);
        } else if (oldHook && !newHook) {
            /* If we did have a hook, the link should be inserted in the list. */
            MOZ_ASSERT(!JS_CLIST_IS_EMPTY(&dbg->onNewGlobalObjectWatchersLink));
            JS_REMOVE_AND_INIT_LINK(&dbg->onNewGlobalObjectWatchersLink);
        }
    }

    return true;
}

/* static */ bool
Debugger::getUncaughtExceptionHook(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "get uncaughtExceptionHook", args, dbg);
    args.rval().setObjectOrNull(dbg->uncaughtExceptionHook);
    return true;
}

/* static */ bool
Debugger::setUncaughtExceptionHook(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "set uncaughtExceptionHook", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.set uncaughtExceptionHook", 1))
        return false;
    if (!args[0].isNull() && (!args[0].isObject() || !args[0].toObject().isCallable())) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_ASSIGN_FUNCTION_OR_NULL,
                             "uncaughtExceptionHook");
        return false;
    }
    dbg->uncaughtExceptionHook = args[0].toObjectOrNull();
    args.rval().setUndefined();
    return true;
}

/* static */ bool
Debugger::getAllowUnobservedAsmJS(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "get allowUnobservedAsmJS", args, dbg);
    args.rval().setBoolean(dbg->allowUnobservedAsmJS);
    return true;
}

/* static */ bool
Debugger::setAllowUnobservedAsmJS(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "set allowUnobservedAsmJS", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.set allowUnobservedAsmJS", 1))
        return false;
    dbg->allowUnobservedAsmJS = ToBoolean(args[0]);

    for (WeakGlobalObjectSet::Range r = dbg->debuggees.all(); !r.empty(); r.popFront()) {
        GlobalObject* global = r.front();
        JSCompartment* comp = global->compartment();
        comp->updateDebuggerObservesAsmJS();
    }

    args.rval().setUndefined();
    return true;
}

/* static */ bool
Debugger::getCollectCoverageInfo(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "get collectCoverageInfo", args, dbg);
    args.rval().setBoolean(dbg->collectCoverageInfo);
    return true;
}

/* static */ bool
Debugger::setCollectCoverageInfo(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "set collectCoverageInfo", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.set collectCoverageInfo", 1))
        return false;
    dbg->collectCoverageInfo = ToBoolean(args[0]);

    IsObserving observing = dbg->collectCoverageInfo ? Observing : NotObserving;
    if (!dbg->updateObservesCoverageOnDebuggees(cx, observing))
        return false;

    args.rval().setUndefined();
    return true;
}

/* static */ bool
Debugger::getMemory(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "get memory", args, dbg);
    Value memoryValue = dbg->object->getReservedSlot(JSSLOT_DEBUG_MEMORY_INSTANCE);

    if (!memoryValue.isObject()) {
        RootedObject memory(cx, DebuggerMemory::create(cx, dbg));
        if (!memory)
            return false;
        memoryValue = ObjectValue(*memory);
    }

    args.rval().set(memoryValue);
    return true;
}

/* static */ bool
Debugger::getOnIonCompilation(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(get onIonCompilation)", args, dbg);
    return getHookImpl(cx, args, *dbg, OnIonCompilation);
}

/* static */ bool
Debugger::setOnIonCompilation(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "(set onIonCompilation)", args, dbg);
    return setHookImpl(cx, args, *dbg, OnIonCompilation);
}

/*
 * Given a value used to designate a global (there's quite a variety; see the
 * docs), return the actual designee.
 *
 * Note that this does not check whether the designee is marked "invisible to
 * Debugger" or not; different callers need to handle invisible-to-Debugger
 * globals in different ways.
 */
GlobalObject*
Debugger::unwrapDebuggeeArgument(JSContext* cx, const Value& v)
{
    if (!v.isObject()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_UNEXPECTED_TYPE,
                             "argument", "not a global object");
        return nullptr;
    }

    RootedObject obj(cx, &v.toObject());

    /* If it's a Debugger.Object belonging to this debugger, dereference that. */
    if (obj->getClass() == &DebuggerObject_class) {
        RootedValue rv(cx, v);
        if (!unwrapDebuggeeValue(cx, &rv))
            return nullptr;
        obj = &rv.toObject();
    }

    /* If we have a cross-compartment wrapper, dereference as far as is secure. */
    obj = CheckedUnwrap(obj);
    if (!obj) {
        JS_ReportError(cx, "Permission denied to access object");
        return nullptr;
    }

    /* If that produced an outer window, innerize it. */
    obj = GetInnerObject(obj);
    if (!obj)
        return nullptr;

    /* If that didn't produce a global object, it's an error. */
    if (!obj->is<GlobalObject>()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_UNEXPECTED_TYPE,
                             "argument", "not a global object");
        return nullptr;
    }

    return &obj->as<GlobalObject>();
}

/* static */ bool
Debugger::addDebuggee(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "addDebuggee", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.addDebuggee", 1))
        return false;
    Rooted<GlobalObject*> global(cx, dbg->unwrapDebuggeeArgument(cx, args[0]));
    if (!global)
        return false;

    if (!dbg->addDebuggeeGlobal(cx, global))
        return false;

    RootedValue v(cx, ObjectValue(*global));
    if (!dbg->wrapDebuggeeValue(cx, &v))
        return false;
    args.rval().set(v);
    return true;
}

/* static */ bool
Debugger::addAllGlobalsAsDebuggees(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "addAllGlobalsAsDebuggees", args, dbg);
    for (ZonesIter zone(cx->runtime(), SkipAtoms); !zone.done(); zone.next()) {
        for (CompartmentsInZoneIter c(zone); !c.done(); c.next()) {
            if (c == dbg->object->compartment() || c->options().invisibleToDebugger())
                continue;
            c->scheduledForDestruction = false;
            GlobalObject* global = c->maybeGlobal();
            if (global) {
                Rooted<GlobalObject*> rg(cx, global);
                if (!dbg->addDebuggeeGlobal(cx, rg))
                    return false;
            }
        }
    }

    args.rval().setUndefined();
    return true;
}

/* static */ bool
Debugger::removeDebuggee(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "removeDebuggee", args, dbg);

    if (!args.requireAtLeast(cx, "Debugger.removeDebuggee", 1))
        return false;
    Rooted<GlobalObject*> global(cx, dbg->unwrapDebuggeeArgument(cx, args[0]));
    if (!global)
        return false;

    ExecutionObservableCompartments obs(cx);
    if (!obs.init())
        return false;

    if (dbg->debuggees.has(global)) {
        dbg->removeDebuggeeGlobal(cx->runtime()->defaultFreeOp(), global, nullptr);

        // Only update the compartment if there are no Debuggers left, as it's
        // expensive to check if no other Debugger has a live script or frame hook
        // on any of the current on-stack debuggee frames.
        if (global->getDebuggers()->empty() && !obs.add(global->compartment()))
            return false;
        if (!updateExecutionObservability(cx, obs, NotObserving))
            return false;
    }

    args.rval().setUndefined();
    return true;
}

/* static */ bool
Debugger::removeAllDebuggees(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "removeAllDebuggees", args, dbg);

    ExecutionObservableCompartments obs(cx);
    if (!obs.init())
        return false;

    for (WeakGlobalObjectSet::Enum e(dbg->debuggees); !e.empty(); e.popFront()) {
        Rooted<GlobalObject*> global(cx, e.front());
        dbg->removeDebuggeeGlobal(cx->runtime()->defaultFreeOp(), global, &e);

        // See note about adding to the observable set in removeDebuggee.
        if (global->getDebuggers()->empty() && !obs.add(global->compartment()))
            return false;
    }

    if (!updateExecutionObservability(cx, obs, NotObserving))
        return false;

    args.rval().setUndefined();
    return true;
}

/* static */ bool
Debugger::hasDebuggee(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "hasDebuggee", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.hasDebuggee", 1))
        return false;
    GlobalObject* global = dbg->unwrapDebuggeeArgument(cx, args[0]);
    if (!global)
        return false;
    args.rval().setBoolean(!!dbg->debuggees.lookup(global));
    return true;
}

/* static */ bool
Debugger::getDebuggees(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "getDebuggees", args, dbg);

    // Obtain the list of debuggees before wrapping each debuggee, as a GC could
    // update the debuggees set while we are iterating it.
    unsigned count = dbg->debuggees.count();
    AutoValueVector debuggees(cx);
    if (!debuggees.resize(count))
        return false;
    unsigned i = 0;
    {
        JS::AutoCheckCannotGC nogc;
        for (WeakGlobalObjectSet::Enum e(dbg->debuggees); !e.empty(); e.popFront())
            debuggees[i++].setObject(*e.front().get());
    }

    RootedArrayObject arrobj(cx, NewDenseFullyAllocatedArray(cx, count));
    if (!arrobj)
        return false;
    arrobj->ensureDenseInitializedLength(cx, 0, count);
    for (i = 0; i < count; i++) {
        RootedValue v(cx, debuggees[i]);
        if (!dbg->wrapDebuggeeValue(cx, &v))
            return false;
        arrobj->setDenseElement(i, v);
    }

    args.rval().setObject(*arrobj);
    return true;
}

/* static */ bool
Debugger::getNewestFrame(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "getNewestFrame", args, dbg);

    /* Since there may be multiple contexts, use AllFramesIter. */
    for (AllFramesIter i(cx); !i.done(); ++i) {
        if (dbg->observesFrame(i)) {
            // Ensure that Ion frames are rematerialized. Only rematerialized
            // Ion frames may be used as AbstractFramePtrs.
            if (i.isIon() && !i.ensureHasRematerializedFrame(cx))
                return false;
            AbstractFramePtr frame = i.abstractFramePtr();
            ScriptFrameIter iter(i.activation()->cx(), ScriptFrameIter::GO_THROUGH_SAVED);
            while (!iter.hasUsableAbstractFramePtr() || iter.abstractFramePtr() != frame)
                ++iter;
            return dbg->getScriptFrame(cx, iter, args.rval());
        }
    }
    args.rval().setNull();
    return true;
}

/* static */ bool
Debugger::clearAllBreakpoints(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "clearAllBreakpoints", args, dbg);
    for (WeakGlobalObjectSet::Range r = dbg->debuggees.all(); !r.empty(); r.popFront())
        r.front()->compartment()->clearBreakpointsIn(cx->runtime()->defaultFreeOp(),
                                                     dbg, nullptr);
    return true;
}

/* static */ bool
Debugger::construct(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);

    /* Check that the arguments, if any, are cross-compartment wrappers. */
    for (unsigned i = 0; i < args.length(); i++) {
        JSObject* argobj = NonNullObject(cx, args[i]);
        if (!argobj)
            return false;
        if (!argobj->is<CrossCompartmentWrapperObject>()) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_CCW_REQUIRED,
                                 "Debugger");
            return false;
        }
    }

    /* Get Debugger.prototype. */
    RootedValue v(cx);
    RootedObject callee(cx, &args.callee());
    if (!GetProperty(cx, callee, callee, cx->names().prototype, &v))
        return false;
    RootedNativeObject proto(cx, &v.toObject().as<NativeObject>());
    MOZ_ASSERT(proto->getClass() == &Debugger::jsclass);
    /*
     * Make the new Debugger object. Each one has a reference to
     * Debugger.{Frame,Object,Script,Memory}.prototype in reserved slots. The
     * rest of the reserved slots are for hooks; they default to undefined.
     */
    RootedNativeObject obj(cx, NewNativeObjectWithGivenProto(cx, &Debugger::jsclass, proto));
    if (!obj)
        return false;
    for (unsigned slot = JSSLOT_DEBUG_PROTO_START; slot < JSSLOT_DEBUG_PROTO_STOP; slot++)
        obj->setReservedSlot(slot, proto->getReservedSlot(slot));
    obj->setReservedSlot(JSSLOT_DEBUG_MEMORY_INSTANCE, NullValue());

    Debugger* debugger;
    {
        /* Construct the underlying C++ object. */
        AutoInitGCManagedObject<Debugger> dbg(cx->make_unique<Debugger>(cx, obj.get()));
        if (!dbg || !dbg->init(cx))
            return false;

        debugger = dbg.release();
        obj->setPrivate(debugger); // owns the released pointer
    }

    /* Add the initial debuggees, if any. */
    for (unsigned i = 0; i < args.length(); i++) {
        Rooted<GlobalObject*>
            debuggee(cx, &args[i].toObject().as<ProxyObject>().private_().toObject().global());
        if (!debugger->addDebuggeeGlobal(cx, debuggee))
            return false;
    }

    args.rval().setObject(*obj);
    return true;
}

bool
Debugger::addDebuggeeGlobal(JSContext* cx, Handle<GlobalObject*> global)
{
    if (debuggees.has(global))
        return true;

    // Callers should generally be unable to get a reference to a debugger-
    // invisible global in order to pass it to addDebuggee. But this is possible
    // with certain testing aides we expose in the shell, so just make addDebuggee
    // throw in that case.
    JSCompartment* debuggeeCompartment = global->compartment();
    if (debuggeeCompartment->options().invisibleToDebugger()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                             JSMSG_DEBUG_CANT_DEBUG_GLOBAL);
        return false;
    }

    /*
     * Check for cycles. If global's compartment is reachable from this
     * Debugger object's compartment by following debuggee-to-debugger links,
     * then adding global would create a cycle. (Typically nobody is debugging
     * the debugger, in which case we zip through this code without looping.)
     */
    Vector<JSCompartment*> visited(cx);
    if (!visited.append(object->compartment()))
        return false;
    for (size_t i = 0; i < visited.length(); i++) {
        JSCompartment* c = visited[i];
        if (c == debuggeeCompartment) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_LOOP);
            return false;
        }

        /*
         * Find all compartments containing debuggers debugging c's global
         * object. Add those compartments to visited.
         */
        if (c->isDebuggee()) {
            GlobalObject::DebuggerVector* v = c->maybeGlobal()->getDebuggers();
            for (Debugger** p = v->begin(); p != v->end(); p++) {
                JSCompartment* next = (*p)->object->compartment();
                if (Find(visited, next) == visited.end() && !visited.append(next))
                    return false;
            }
        }
    }

    /*
     * For global to become this js::Debugger's debuggee:
     *
     * 1. this js::Debugger must be in global->getDebuggers(),
     * 2. global must be in this->debuggees,
     * 3. it must be in zone->getDebuggers(),
     * 4. the debuggee's zone must be in this->debuggeeZones,
     * 5. if we are tracking allocations, the SavedStacksMetadataCallback must be
     *    installed for this compartment, and
     * 6. JSCompartment::isDebuggee()'s bit must be set.
     *
     * All six indications must be kept consistent.
     */

    AutoCompartment ac(cx, global);
    Zone* zone = global->zone();

    // (1)
    auto* globalDebuggers = GlobalObject::getOrCreateDebuggers(cx, global);
    if (!globalDebuggers)
        return false;
    if (!globalDebuggers->append(this)) {
        ReportOutOfMemory(cx);
        return false;
    }
    auto globalDebuggersGuard = MakeScopeExit([&] {
        globalDebuggers->popBack();
    });

    // (2)
    if (!debuggees.put(global)) {
        ReportOutOfMemory(cx);
        return false;
    }
    auto debuggeesGuard = MakeScopeExit([&] {
        debuggees.remove(global);
    });

    bool addingZoneRelation = !debuggeeZones.has(zone);

    // (3)
    auto* zoneDebuggers = zone->getOrCreateDebuggers(cx);
    if (!zoneDebuggers)
        return false;
    if (addingZoneRelation && !zoneDebuggers->append(this)) {
        ReportOutOfMemory(cx);
        return false;
    }
    auto zoneDebuggersGuard = MakeScopeExit([&] {
        if (addingZoneRelation)
            zoneDebuggers->popBack();
    });

    // (4)
    if (addingZoneRelation && !debuggeeZones.put(zone)) {
        ReportOutOfMemory(cx);
        return false;
    }
    auto debuggeeZonesGuard = MakeScopeExit([&] {
        if (addingZoneRelation)
            debuggeeZones.remove(zone);
    });

    // (5)
    if (trackingAllocationSites && !Debugger::addAllocationsTracking(cx, *global))
            return false;
    auto allocationsTrackingGuard = MakeScopeExit([&] {
        if (trackingAllocationSites)
            Debugger::removeAllocationsTracking(*global);
    });

    // (6)
    debuggeeCompartment->setIsDebuggee();
    debuggeeCompartment->updateDebuggerObservesAsmJS();
    debuggeeCompartment->updateDebuggerObservesCoverage();
    if (observesAllExecution() && !ensureExecutionObservabilityOfCompartment(cx, debuggeeCompartment))
        return false;

    globalDebuggersGuard.release();
    debuggeesGuard.release();
    zoneDebuggersGuard.release();
    debuggeeZonesGuard.release();
    allocationsTrackingGuard.release();
    return true;
}

bool
Debugger::recomputeDebuggeeZoneSet()
{
    debuggeeZones.clear();
    for (auto range = debuggees.all(); !range.empty(); range.popFront()) {
        if (!debuggeeZones.put(range.front()->zone()))
            return false;
    }
    return true;
}

template<typename V>
static Debugger**
findDebuggerInVector(Debugger* dbg, V* vec)
{
    Debugger** p;
    for (p = vec->begin(); p != vec->end(); p++) {
        if (*p == dbg)
            break;
    }
    MOZ_ASSERT(p != vec->end());
    return p;
}

void
Debugger::removeDebuggeeGlobal(FreeOp* fop, GlobalObject* global,
                               WeakGlobalObjectSet::Enum* debugEnum)
{
    /*
     * The caller might have found global by enumerating this->debuggees; if
     * so, use HashSet::Enum::removeFront rather than HashSet::remove below,
     * to avoid invalidating the live enumerator.
     */
    MOZ_ASSERT(debuggees.has(global));
    MOZ_ASSERT(debuggeeZones.has(global->zone()));
    MOZ_ASSERT_IF(debugEnum, debugEnum->front() == global);

    /*
     * FIXME Debugger::slowPathOnLeaveFrame needs to kill all Debugger.Frame
     * objects referring to a particular JS stack frame. This is hard if
     * Debugger objects that are no longer debugging the relevant global might
     * have live Frame objects. So we take the easy way out and kill them here.
     * This is a bug, since it's observable and contrary to the spec. One
     * possible fix would be to put such objects into a compartment-wide bag
     * which slowPathOnLeaveFrame would have to examine.
     */
    for (FrameMap::Enum e(frames); !e.empty(); e.popFront()) {
        AbstractFramePtr frame = e.front().key();
        NativeObject* frameobj = e.front().value();
        if (&frame.script()->global() == global) {
            DebuggerFrame_freeScriptFrameIterData(fop, frameobj);
            DebuggerFrame_maybeDecrementFrameScriptStepModeCount(fop, frame, frameobj);
            e.removeFront();
        }
    }

    auto *globalDebuggersVector = global->getDebuggers();
    auto *zoneDebuggersVector = global->zone()->getDebuggers();

    /*
     * The relation must be removed from up to three places:
     * globalDebuggersVector and debuggees for sure, and possibly the
     * compartment's debuggee set.
     *
     * The debuggee zone set is recomputed on demand. This avoids refcounting
     * and in practice we have relatively few debuggees that tend to all be in
     * the same zone. If after recomputing the debuggee zone set, this global's
     * zone is not in the set, then we must remove ourselves from the zone's
     * vector of observing debuggers.
     */
    globalDebuggersVector->erase(findDebuggerInVector(this, globalDebuggersVector));

    if (debugEnum)
        debugEnum->removeFront();
    else
        debuggees.remove(global);

    if (!recomputeDebuggeeZoneSet())
        CrashAtUnhandlableOOM("Debugger::removeDebuggeeGlobal");
    if (!debuggeeZones.has(global->zone()))
        zoneDebuggersVector->erase(findDebuggerInVector(this, zoneDebuggersVector));

    /* Remove all breakpoints for the debuggee. */
    Breakpoint* nextbp;
    for (Breakpoint* bp = firstBreakpoint(); bp; bp = nextbp) {
        nextbp = bp->nextInDebugger();
        if (bp->site->script->compartment() == global->compartment())
            bp->destroy(fop);
    }
    MOZ_ASSERT_IF(debuggees.empty(), !firstBreakpoint());

    /*
     * If we are tracking allocation sites, we need to remove the object
     * metadata callback from this global's compartment.
     */
    if (trackingAllocationSites)
        Debugger::removeAllocationsTracking(*global);

    if (global->getDebuggers()->empty()) {
        global->compartment()->unsetIsDebuggee();
    } else {
        global->compartment()->updateDebuggerObservesAllExecution();
        global->compartment()->updateDebuggerObservesAsmJS();
        global->compartment()->updateDebuggerObservesCoverage();
    }
}


static inline ScriptSourceObject* GetSourceReferent(JSObject* obj);

/*
 * A class for parsing 'findScripts' query arguments and searching for
 * scripts that match the criteria they represent.
 */
class MOZ_STACK_CLASS Debugger::ScriptQuery
{
  public:
    /* Construct a ScriptQuery to use matching scripts for |dbg|. */
    ScriptQuery(JSContext* cx, Debugger* dbg):
        cx(cx), debugger(dbg), compartments(cx->runtime()), url(cx), displayURLString(cx),
        source(cx), innermostForCompartment(cx->runtime()), vector(cx, ScriptVector(cx))
    {}

    /*
     * Initialize this ScriptQuery. Raise an error and return false if we
     * haven't enough memory.
     */
    bool init() {
        if (!compartments.init() ||
            !innermostForCompartment.init())
        {
            ReportOutOfMemory(cx);
            return false;
        }

        return true;
    }

    /*
     * Parse the query object |query|, and prepare to match only the scripts
     * it specifies.
     */
    bool parseQuery(HandleObject query) {
        /*
         * Check for a 'global' property, which limits the results to those
         * scripts scoped to a particular global object.
         */
        RootedValue global(cx);
        if (!GetProperty(cx, query, query, cx->names().global, &global))
            return false;
        if (global.isUndefined()) {
            matchAllDebuggeeGlobals();
        } else {
            GlobalObject* globalObject = debugger->unwrapDebuggeeArgument(cx, global);
            if (!globalObject)
                return false;

            /*
             * If the given global isn't a debuggee, just leave the set of
             * acceptable globals empty; we'll return no scripts.
             */
            if (debugger->debuggees.has(globalObject)) {
                if (!matchSingleGlobal(globalObject))
                    return false;
            }
        }

        /* Check for a 'url' property. */
        if (!GetProperty(cx, query, query, cx->names().url, &url))
            return false;
        if (!url.isUndefined() && !url.isString()) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_UNEXPECTED_TYPE,
                                 "query object's 'url' property", "neither undefined nor a string");
            return false;
        }

        /* Check for a 'source' property */
        RootedValue debuggerSource(cx);
        if (!GetProperty(cx, query, query, cx->names().source, &debuggerSource))
            return false;
        if (!debuggerSource.isUndefined()) {
            if (!debuggerSource.isObject() ||
                debuggerSource.toObject().getClass() != &DebuggerSource_class) {
                JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_UNEXPECTED_TYPE,
                                     "query object's 'source' property",
                                     "not undefined nor a Debugger.Source object");
                return false;
            }

            source = GetSourceReferent(&debuggerSource.toObject());
        }

        /* Check for a 'displayURL' property. */
        RootedValue displayURL(cx);
        if (!GetProperty(cx, query, query, cx->names().displayURL, &displayURL))
            return false;
        if (!displayURL.isUndefined() && !displayURL.isString()) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_UNEXPECTED_TYPE,
                                 "query object's 'displayURL' property",
                                 "neither undefined nor a string");
            return false;
        }

        if (displayURL.isString()) {
            displayURLString = displayURL.toString()->ensureLinear(cx);
            if (!displayURLString)
                return false;
        }

        /* Check for a 'line' property. */
        RootedValue lineProperty(cx);
        if (!GetProperty(cx, query, query, cx->names().line, &lineProperty))
            return false;
        if (lineProperty.isUndefined()) {
            hasLine = false;
        } else if (lineProperty.isNumber()) {
            if (displayURL.isUndefined() && url.isUndefined() && !source) {
                JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                                     JSMSG_QUERY_LINE_WITHOUT_URL);
                return false;
            }
            double doubleLine = lineProperty.toNumber();
            if (doubleLine <= 0 || (unsigned int) doubleLine != doubleLine) {
                JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_BAD_LINE);
                return false;
            }
            hasLine = true;
            line = doubleLine;
        } else {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_UNEXPECTED_TYPE,
                                 "query object's 'line' property",
                                 "neither undefined nor an integer");
            return false;
        }

        /* Check for an 'innermost' property. */
        PropertyName* innermostName = cx->names().innermost;
        RootedValue innermostProperty(cx);
        if (!GetProperty(cx, query, query, innermostName, &innermostProperty))
            return false;
        innermost = ToBoolean(innermostProperty);
        if (innermost) {
            /* Technically, we need only check hasLine, but this is clearer. */
            if ((displayURL.isUndefined() && url.isUndefined() && !source) || !hasLine) {
                JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                                     JSMSG_QUERY_INNERMOST_WITHOUT_LINE_URL);
                return false;
            }
        }

        return true;
    }

    /* Set up this ScriptQuery appropriately for a missing query argument. */
    bool omittedQuery() {
        url.setUndefined();
        hasLine = false;
        innermost = false;
        displayURLString = nullptr;
        return matchAllDebuggeeGlobals();
    }

    /*
     * Search all relevant compartments and the stack for scripts matching
     * this query, and append the matching scripts to |vector|.
     */
    bool findScripts() {
        if (!prepareQuery())
            return false;

        JSCompartment* singletonComp = nullptr;
        if (compartments.count() == 1)
            singletonComp = compartments.all().front();

        /* Search each compartment for debuggee scripts. */
        MOZ_ASSERT(vector.empty());
        oom = false;
        IterateScripts(cx->runtime(), singletonComp, this, considerScript);
        if (oom) {
            ReportOutOfMemory(cx);
            return false;
        }

        /* We cannot touch the gray bits while isHeapBusy, so do this now. */
        for (JSScript** i = vector.begin(); i != vector.end(); ++i)
            JS::ExposeScriptToActiveJS(*i);

        /*
         * For most queries, we just accumulate results in 'vector' as we find
         * them. But if this is an 'innermost' query, then we've accumulated the
         * results in the 'innermostForCompartment' map. In that case, we now need to
         * walk that map and populate 'vector'.
         */
        if (innermost) {
            for (CompartmentToScriptMap::Range r = innermostForCompartment.all();
                 !r.empty();
                 r.popFront())
            {
                JS::ExposeScriptToActiveJS(r.front().value());
                if (!vector.append(r.front().value())) {
                    ReportOutOfMemory(cx);
                    return false;
                }
            }
        }

        return true;
    }

    Handle<ScriptVector> foundScripts() const {
        return vector;
    }

  private:
    /* The context in which we should do our work. */
    JSContext* cx;

    /* The debugger for which we conduct queries. */
    Debugger* debugger;

    typedef HashSet<JSCompartment*, DefaultHasher<JSCompartment*>, RuntimeAllocPolicy>
        CompartmentSet;

    /* A script must be in one of these compartments to match the query. */
    CompartmentSet compartments;

    /* If this is a string, matching scripts have urls equal to it. */
    RootedValue url;

    /* url as a C string. */
    JSAutoByteString urlCString;

    /* If this is a string, matching scripts' sources have displayURLs equal to
     * it. */
    RootedLinearString displayURLString;

    /*
     * If this is a source object, matching scripts will have sources
     * equal to this instance.
     */
    RootedScriptSource source;

    /* True if the query contained a 'line' property. */
    bool hasLine;

    /* The line matching scripts must cover. */
    unsigned int line;

    /* True if the query has an 'innermost' property whose value is true. */
    bool innermost;

    typedef HashMap<JSCompartment*, JSScript*, DefaultHasher<JSCompartment*>, RuntimeAllocPolicy>
        CompartmentToScriptMap;

    /*
     * For 'innermost' queries, a map from compartments to the innermost script
     * we've seen so far in that compartment. (Template instantiation code size
     * explosion ho!)
     */
    CompartmentToScriptMap innermostForCompartment;

    /*
     * Accumulate the scripts in an Rooted<ScriptVector>, instead of creating
     * the JS array as we go, because we mustn't allocate JS objects or GC
     * while we use the CellIter.
     */
    Rooted<ScriptVector> vector;

    /* Indicates whether OOM has occurred while matching. */
    bool oom;

    bool addCompartment(JSCompartment* comp) {
        {
            // All scripts in the debuggee compartment must be visible, so
            // delazify everything.
            AutoCompartment ac(cx, comp);
            if (!comp->ensureDelazifyScriptsForDebugger(cx))
                return false;
        }
        return compartments.put(comp);
    }

    /* Arrange for this ScriptQuery to match only scripts that run in |global|. */
    bool matchSingleGlobal(GlobalObject* global) {
        MOZ_ASSERT(compartments.count() == 0);
        if (!addCompartment(global->compartment())) {
            ReportOutOfMemory(cx);
            return false;
        }
        return true;
    }

    /*
     * Arrange for this ScriptQuery to match all scripts running in debuggee
     * globals.
     */
    bool matchAllDebuggeeGlobals() {
        MOZ_ASSERT(compartments.count() == 0);
        /* Build our compartment set from the debugger's set of debuggee globals. */
        for (WeakGlobalObjectSet::Range r = debugger->debuggees.all(); !r.empty(); r.popFront()) {
            if (!addCompartment(r.front()->compartment())) {
                ReportOutOfMemory(cx);
                return false;
            }
        }
        return true;
    }

    /*
     * Given that parseQuery or omittedQuery has been called, prepare to match
     * scripts. Set urlCString and displayURLChars as appropriate.
     */
    bool prepareQuery() {
        /* Compute urlCString and displayURLChars, if a url or displayURL was
         * given respectively. */
        if (url.isString()) {
            if (!urlCString.encodeLatin1(cx, url.toString()))
                return false;
        }

        return true;
    }

    static void considerScript(JSRuntime* rt, void* data, JSScript* script) {
        ScriptQuery* self = static_cast<ScriptQuery*>(data);
        self->consider(script);
    }

    /*
     * If |script| matches this query, append it to |vector| or place it in
     * |innermostForCompartment|, as appropriate. Set |oom| if an out of memory
     * condition occurred.
     */
    void consider(JSScript* script) {
        // We check for presence of script->code() because it is possible that
        // the script was created and thus exposed to GC, but *not* fully
        // initialized from fullyInit{FromEmitter,Trivial} due to errors.
        if (oom || script->selfHosted() || !script->code())
            return;
        JSCompartment* compartment = script->compartment();
        if (!compartments.has(compartment))
            return;
        if (urlCString.ptr()) {
            bool gotFilename = false;
            if (script->filename() && strcmp(script->filename(), urlCString.ptr()) == 0)
                gotFilename = true;

            bool gotSourceURL = false;
            if (!gotFilename && script->scriptSource()->introducerFilename() &&
                strcmp(script->scriptSource()->introducerFilename(), urlCString.ptr()) == 0)
            {
                gotSourceURL = true;
            }
            if (!gotFilename && !gotSourceURL)
                return;
        }
        if (hasLine) {
            if (line < script->lineno() || script->lineno() + GetScriptLineExtent(script) < line)
                return;
        }
        if (displayURLString) {
            if (!script->scriptSource() || !script->scriptSource()->hasDisplayURL())
                return;

            const char16_t* s = script->scriptSource()->displayURL();
            if (CompareChars(s, js_strlen(s), displayURLString) != 0)
                return;
        }
        if (source && source != script->sourceObject())
            return;

        if (innermost) {
            /*
             * For 'innermost' queries, we don't place scripts in |vector| right
             * away; we may later find another script that is nested inside this
             * one. Instead, we record the innermost script we've found so far
             * for each compartment in innermostForCompartment, and only
             * populate |vector| at the bottom of findScripts, when we've
             * traversed all the scripts.
             *
             * So: check this script against the innermost one we've found so
             * far (if any), as recorded in innermostForCompartment, and replace
             * that if it's better.
             */
            CompartmentToScriptMap::AddPtr p = innermostForCompartment.lookupForAdd(compartment);
            if (p) {
                /* Is our newly found script deeper than the last one we found? */
                JSScript* incumbent = p->value();
                if (StaticScopeChainLength(script->innermostStaticScope()) >
                    StaticScopeChainLength(incumbent->innermostStaticScope()))
                {
                    p->value() = script;
                }
            } else {
                /*
                 * This is the first matching script we've encountered for this
                 * compartment, so it is thus the innermost such script.
                 */
                if (!innermostForCompartment.add(p, compartment, script)) {
                    oom = true;
                    return;
                }
            }
        } else {
            /* Record this matching script in the results vector. */
            if (!vector.append(script)) {
                oom = true;
                return;
            }
        }

        return;
    }
};

/* static */ bool
Debugger::findScripts(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "findScripts", args, dbg);

    ScriptQuery query(cx, dbg);
    if (!query.init())
        return false;

    if (args.length() >= 1) {
        RootedObject queryObject(cx, NonNullObject(cx, args[0]));
        if (!queryObject || !query.parseQuery(queryObject))
            return false;
    } else {
        if (!query.omittedQuery())
            return false;
    }

    if (!query.findScripts())
        return false;

    Handle<ScriptVector> scripts(query.foundScripts());
    RootedArrayObject result(cx, NewDenseFullyAllocatedArray(cx, scripts.length()));
    if (!result)
        return false;

    result->ensureDenseInitializedLength(cx, 0, scripts.length());

    for (size_t i = 0; i < scripts.length(); i++) {
        JSObject* scriptObject = dbg->wrapScript(cx, scripts[i]);
        if (!scriptObject)
            return false;
        result->setDenseElement(i, ObjectValue(*scriptObject));
    }

    args.rval().setObject(*result);
    return true;
}

/*
 * A class for parsing 'findObjects' query arguments and searching for objects
 * that match the criteria they represent.
 */
class MOZ_STACK_CLASS Debugger::ObjectQuery
{
  public:
    /* Construct an ObjectQuery to use matching scripts for |dbg|. */
    ObjectQuery(JSContext* cx, Debugger* dbg) :
        objects(cx), cx(cx), dbg(dbg), className(cx)
    { }

    /* The vector that we are accumulating results in. */
    AutoObjectVector objects;

    /*
     * Parse the query object |query|, and prepare to match only the objects it
     * specifies.
     */
    bool parseQuery(HandleObject query) {
        /* Check for the 'class' property */
        RootedValue cls(cx);
        if (!GetProperty(cx, query, query, cx->names().class_, &cls))
            return false;
        if (!cls.isUndefined()) {
            if (!cls.isString()) {
                JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_UNEXPECTED_TYPE,
                                     "query object's 'class' property",
                                     "neither undefined nor a string");
                return false;
            }
            className = cls;
        }
        return true;
    }

    /* Set up this ObjectQuery appropriately for a missing query argument. */
    void omittedQuery() {
        className.setUndefined();
    }

    /*
     * Traverse the heap to find all relevant objects and add them to the
     * provided vector.
     */
    bool findObjects() {
        if (!prepareQuery())
            return false;

        {
            /*
             * We can't tolerate the GC moving things around while we're
             * searching the heap. Check that nothing we do causes a GC.
             */
            Maybe<JS::AutoCheckCannotGC> maybeNoGC;
            RootedObject dbgObj(cx, dbg->object);
            JS::ubi::RootList rootList(cx, maybeNoGC);
            if (!rootList.init(dbgObj))
                return false;

            Traversal traversal(cx, *this, maybeNoGC.ref());
            if (!traversal.init())
                return false;
            traversal.wantNames = false;

            return traversal.addStart(JS::ubi::Node(&rootList)) &&
                   traversal.traverse();
        }
    }

    /*
     * |ubi::Node::BreadthFirst| interface.
     */
    class NodeData {};
    typedef JS::ubi::BreadthFirst<ObjectQuery> Traversal;
    bool operator() (Traversal& traversal, JS::ubi::Node origin, const JS::ubi::Edge& edge,
                     NodeData*, bool first)
    {
        if (!first)
            return true;

        JS::ubi::Node referent = edge.referent;
        /*
         * Only follow edges within our set of debuggee compartments; we don't
         * care about the heap's subgraphs outside of our debuggee compartments,
         * so we abandon the referent. Either (1) there is not a path from this
         * non-debuggee node back to a node in our debuggee compartments, and we
         * don't need to follow edges to or from this node, or (2) there does
         * exist some path from this non-debuggee node back to a node in our
         * debuggee compartments. However, if that were true, then the incoming
         * cross compartment edge back into a debuggee compartment is already
         * listed as an edge in the RootList we started traversal with, and
         * therefore we don't need to follow edges to or from this non-debuggee
         * node.
         */
        JSCompartment* comp = referent.compartment();
        if (comp && !dbg->isDebuggee(comp)) {
            traversal.abandonReferent();
            return true;
        }

        /*
         * If the referent is an object and matches our query's restrictions,
         * add it to the vector accumulating results. Skip objects that should
         * never be exposed to JS, like ScopeObjects and internal functions.
         */

        if (!referent.is<JSObject>() || referent.exposeToJS().isUndefined())
            return true;

        JSObject* obj = referent.as<JSObject>();

        if (!className.isUndefined()) {
            const char* objClassName = obj->getClass()->name;
            if (strcmp(objClassName, classNameCString.ptr()) != 0)
                return true;
        }

        return objects.append(obj);
    }

  private:
    /* The context in which we should do our work. */
    JSContext* cx;

    /* The debugger for which we conduct queries. */
    Debugger* dbg;

    /*
     * If this is non-null, matching objects will have a class whose name is
     * this property.
     */
    RootedValue className;

    /* The className member, as a C string. */
    JSAutoByteString classNameCString;

    /*
     * Given that either omittedQuery or parseQuery has been called, prepare the
     * query for matching objects.
     */
    bool prepareQuery() {
        if (className.isString()) {
            if (!classNameCString.encodeLatin1(cx, className.toString()))
                return false;
        }

        return true;
    }
};

bool
Debugger::findObjects(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "findObjects", args, dbg);

    ObjectQuery query(cx, dbg);

    if (args.length() >= 1) {
        RootedObject queryObject(cx, NonNullObject(cx, args[0]));
        if (!queryObject || !query.parseQuery(queryObject))
            return false;
    } else {
        query.omittedQuery();
    }

    if (!query.findObjects())
        return false;

    size_t length = query.objects.length();
    RootedArrayObject result(cx, NewDenseFullyAllocatedArray(cx, length));
    if (!result)
        return false;

    result->ensureDenseInitializedLength(cx, 0, length);

    for (size_t i = 0; i < length; i++) {
        RootedValue debuggeeVal(cx, ObjectValue(*query.objects[i]));
        if (!dbg->wrapDebuggeeValue(cx, &debuggeeVal))
            return false;
        result->setDenseElement(i, debuggeeVal);
    }

    args.rval().setObject(*result);
    return true;
}

/* static */ bool
Debugger::findAllGlobals(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "findAllGlobals", args, dbg);

    AutoObjectVector globals(cx);

    {
        // Accumulate the list of globals before wrapping them, because
        // wrapping can GC and collect compartments from under us, while
        // iterating.
        JS::AutoCheckCannotGC nogc;

        for (CompartmentsIter c(cx->runtime(), SkipAtoms); !c.done(); c.next()) {
            if (c->options().invisibleToDebugger())
                continue;

            c->scheduledForDestruction = false;

            GlobalObject* global = c->maybeGlobal();

            if (cx->runtime()->isSelfHostingGlobal(global))
                continue;

            if (global) {
                /*
                 * We pulled |global| out of nowhere, so it's possible that it was
                 * marked gray by XPConnect. Since we're now exposing it to JS code,
                 * we need to mark it black.
                 */
                JS::ExposeObjectToActiveJS(global);
                if (!globals.append(global))
                    return false;
            }
        }
    }

    RootedObject result(cx, NewDenseEmptyArray(cx));
    if (!result)
        return false;

    for (size_t i = 0; i < globals.length(); i++) {
        RootedValue globalValue(cx, ObjectValue(*globals[i]));
        if (!dbg->wrapDebuggeeValue(cx, &globalValue))
            return false;
        if (!NewbornArrayPush(cx, result, globalValue))
            return false;
    }

    args.rval().setObject(*result);
    return true;
}

/* static */ bool
Debugger::makeGlobalObjectReference(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "makeGlobalObjectReference", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.makeGlobalObjectReference", 1))
        return false;

    Rooted<GlobalObject*> global(cx, dbg->unwrapDebuggeeArgument(cx, args[0]));
    if (!global)
        return false;

    // If we create a D.O referring to a global in an invisible compartment,
    // then from it we can reach function objects, scripts, environments, etc.,
    // none of which we're ever supposed to see.
    JSCompartment* globalCompartment = global->compartment();
    if (globalCompartment->options().invisibleToDebugger()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                             JSMSG_DEBUG_INVISIBLE_COMPARTMENT);
        return false;
    }

    args.rval().setObject(*global);
    return dbg->wrapDebuggeeValue(cx, args.rval());
}

static bool
DefineProperty(JSContext* cx, HandleObject obj, HandleId id, const char* value, size_t n)
{
    JSString* text = JS_NewStringCopyN(cx, value, n);
    if (!text)
        return false;

    RootedValue str(cx, StringValue(text));
    return JS_DefinePropertyById(cx, obj, id, str, JSPROP_ENUMERATE);
}

#ifdef JS_TRACE_LOGGING
# ifdef NIGHTLY_BUILD
bool
Debugger::setupTraceLogger(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "setupTraceLogger", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.setupTraceLogger", 1))
        return false;

    RootedObject obj(cx, ToObject(cx, args[0]));
    if (!obj)
        return false;

    AutoIdVector ids(cx);
    if (!GetPropertyKeys(cx, obj, JSITER_OWNONLY, &ids))
        return false;

    if (ids.length() == 0) {
        args.rval().setBoolean(true);
        return true;
    }

    Vector<uint32_t> textIds(cx);
    if (!textIds.reserve(ids.length()))
        return false;

    Vector<bool> values(cx);
    if (!values.reserve(ids.length()))
        return false;

    for (size_t i = 0; i < ids.length(); i++) {
        if (!JSID_IS_STRING(ids[i])) {
            args.rval().setBoolean(false);
            return true;
        }

        JSString* id = JSID_TO_STRING(ids[i]);
        JSLinearString* linear = id->ensureLinear(cx);
        if (!linear)
            return false;

        uint32_t textId = TLStringToTextId(linear);

        if (!TLTextIdIsToggable(textId)) {
            args.rval().setBoolean(false);
            return true;
        }

        RootedValue v(cx);
        if (!GetProperty(cx, obj, obj, ids[i], &v))
            return false;

        textIds.append(textId);
        values.append(ToBoolean(v));
    }

    MOZ_ASSERT(ids.length() == textIds.length());
    MOZ_ASSERT(textIds.length() == values.length());

    for (size_t i = 0; i < textIds.length(); i++) {
        if (values[i])
            TraceLogEnableTextId(cx, textIds[i]);
        else
            TraceLogDisableTextId(cx, textIds[i]);
    }

    args.rval().setBoolean(true);
    return true;
}

bool
Debugger::drainTraceLogger(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "drainTraceLogger", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.drainTraceLogger", 0))
        return false;

    size_t num;
    TraceLoggerThread* logger = TraceLoggerForMainThread(cx->runtime());
    bool lostEvents = logger->lostEvents(dbg->traceLoggerLastDrainedIteration,
                                         dbg->traceLoggerLastDrainedId);
    EventEntry* events = logger->getEventsStartingAt(&dbg->traceLoggerLastDrainedIteration,
                                                     &dbg->traceLoggerLastDrainedId,
                                                     &num);

    RootedObject array(cx, NewDenseEmptyArray(cx));
    JSAtom* dataAtom = Atomize(cx, "data", strlen("data"));
    if (!dataAtom)
        return false;
    RootedId dataId(cx, AtomToId(dataAtom));

    /* Add all events to the array. */
    uint32_t index = 0;
    for (EventEntry* eventItem = events; eventItem < events + num; eventItem++, index++) {
        RootedObject item(cx, NewObjectWithGivenProto(cx, &PlainObject::class_, nullptr));
        if (!item)
            return false;

        const char* eventText = logger->eventText(eventItem->textId);
        if (!DefineProperty(cx, item, dataId, eventText, strlen(eventText)))
            return false;

        RootedValue obj(cx, ObjectValue(*item));
        if (!JS_DefineElement(cx, array, index, obj, JSPROP_ENUMERATE))
            return false;
    }

    /* Add "lostEvents" indicating if there are events that were lost. */
    RootedValue lost(cx, BooleanValue(lostEvents));
    if (!JS_DefineProperty(cx, array, "lostEvents", lost, JSPROP_ENUMERATE))
        return false;

    args.rval().setObject(*array);

    return true;
}
# endif // NIGHTLY_BUILD

bool
Debugger::setupTraceLoggerScriptCalls(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "setupTraceLoggerScriptCalls", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.setupTraceLoggerScriptCalls", 0))
        return false;

    TraceLogEnableTextId(cx, TraceLogger_Scripts);
    TraceLogEnableTextId(cx, TraceLogger_InlinedScripts);
    TraceLogDisableTextId(cx, TraceLogger_AnnotateScripts);

    args.rval().setBoolean(true);

    return true;
}

bool
Debugger::startTraceLogger(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "startTraceLogger", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.startTraceLogger", 0))
        return false;

    TraceLoggerThread* logger = TraceLoggerForMainThread(cx->runtime());
    if (!TraceLoggerEnable(logger, cx))
        return false;

    args.rval().setUndefined();

    return true;
}

bool
Debugger::endTraceLogger(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "endTraceLogger", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.endTraceLogger", 0))
        return false;

    TraceLoggerThread* logger = TraceLoggerForMainThread(cx->runtime());
    TraceLoggerDisable(logger);

    args.rval().setUndefined();

    return true;
}

bool
Debugger::drainTraceLoggerScriptCalls(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGGER(cx, argc, vp, "drainTraceLoggerScriptCalls", args, dbg);
    if (!args.requireAtLeast(cx, "Debugger.drainTraceLoggerScriptCalls", 0))
        return false;

    size_t num;
    TraceLoggerThread* logger = TraceLoggerForMainThread(cx->runtime());
    bool lostEvents = logger->lostEvents(dbg->traceLoggerScriptedCallsLastDrainedIteration,
                                         dbg->traceLoggerScriptedCallsLastDrainedId);
    EventEntry* events = logger->getEventsStartingAt(
                                         &dbg->traceLoggerScriptedCallsLastDrainedIteration,
                                         &dbg->traceLoggerScriptedCallsLastDrainedId,
                                         &num);

    RootedObject array(cx, NewDenseEmptyArray(cx));
    RootedId fileNameId(cx, AtomToId(cx->names().fileName));
    RootedId lineNumberId(cx, AtomToId(cx->names().lineNumber));
    RootedId columnNumberId(cx, AtomToId(cx->names().columnNumber));
    JSAtom* logTypeAtom = Atomize(cx, "logType", strlen("logType"));
    if (!logTypeAtom)
        return false;
    RootedId logTypeId(cx, AtomToId(logTypeAtom));

    /* Add all events to the array. */
    uint32_t index = 0;
    for (EventEntry* eventItem = events; eventItem < events + num; eventItem++) {
        RootedObject item(cx, NewObjectWithGivenProto(cx, &PlainObject::class_, nullptr));
        if (!item)
            return false;

        uint32_t textId = eventItem->textId;
        if (textId != TraceLogger_Stop && !logger->textIdIsScriptEvent(textId))
            continue;

        const char* type = (textId == TraceLogger_Stop) ? "Stop" : "Script";
        if (!DefineProperty(cx, item, logTypeId, type, strlen(type)))
            return false;

        if (textId != TraceLogger_Stop) {
            const char* filename;
            const char* lineno;
            const char* colno;
            size_t filename_len, lineno_len, colno_len;
            logger->extractScriptDetails(textId, &filename, &filename_len, &lineno, &lineno_len,
                                         &colno, &colno_len);

            if (!DefineProperty(cx, item, fileNameId, filename, filename_len))
                return false;
            if (!DefineProperty(cx, item, lineNumberId, lineno, lineno_len))
                return false;
            if (!DefineProperty(cx, item, columnNumberId, colno, colno_len))
                return false;
        }

        RootedValue obj(cx, ObjectValue(*item));
        if (!JS_DefineElement(cx, array, index, obj, JSPROP_ENUMERATE))
            return false;

        index++;
    }

    /* Add "lostEvents" indicating if there are events that were lost. */
    RootedValue lost(cx, BooleanValue(lostEvents));
    if (!JS_DefineProperty(cx, array, "lostEvents", lost, JSPROP_ENUMERATE))
        return false;

    args.rval().setObject(*array);

    return true;
}
#endif

const JSPropertySpec Debugger::properties[] = {
    JS_PSGS("enabled", Debugger::getEnabled, Debugger::setEnabled, 0),
    JS_PSGS("onDebuggerStatement", Debugger::getOnDebuggerStatement,
            Debugger::setOnDebuggerStatement, 0),
    JS_PSGS("onExceptionUnwind", Debugger::getOnExceptionUnwind,
            Debugger::setOnExceptionUnwind, 0),
    JS_PSGS("onNewScript", Debugger::getOnNewScript, Debugger::setOnNewScript, 0),
    JS_PSGS("onNewPromise", Debugger::getOnNewPromise, Debugger::setOnNewPromise, 0),
    JS_PSGS("onPromiseSettled", Debugger::getOnPromiseSettled, Debugger::setOnPromiseSettled, 0),
    JS_PSGS("onEnterFrame", Debugger::getOnEnterFrame, Debugger::setOnEnterFrame, 0),
    JS_PSGS("onNewGlobalObject", Debugger::getOnNewGlobalObject, Debugger::setOnNewGlobalObject, 0),
    JS_PSGS("uncaughtExceptionHook", Debugger::getUncaughtExceptionHook,
            Debugger::setUncaughtExceptionHook, 0),
    JS_PSGS("allowUnobservedAsmJS", Debugger::getAllowUnobservedAsmJS,
            Debugger::setAllowUnobservedAsmJS, 0),
    JS_PSGS("collectCoverageInfo", Debugger::getCollectCoverageInfo,
            Debugger::setCollectCoverageInfo, 0),
    JS_PSG("memory", Debugger::getMemory, 0),
    JS_PSGS("onIonCompilation", Debugger::getOnIonCompilation, Debugger::setOnIonCompilation, 0),
    JS_PS_END
};
const JSFunctionSpec Debugger::methods[] = {
    JS_FN("addDebuggee", Debugger::addDebuggee, 1, 0),
    JS_FN("addAllGlobalsAsDebuggees", Debugger::addAllGlobalsAsDebuggees, 0, 0),
    JS_FN("removeDebuggee", Debugger::removeDebuggee, 1, 0),
    JS_FN("removeAllDebuggees", Debugger::removeAllDebuggees, 0, 0),
    JS_FN("hasDebuggee", Debugger::hasDebuggee, 1, 0),
    JS_FN("getDebuggees", Debugger::getDebuggees, 0, 0),
    JS_FN("getNewestFrame", Debugger::getNewestFrame, 0, 0),
    JS_FN("clearAllBreakpoints", Debugger::clearAllBreakpoints, 0, 0),
    JS_FN("findScripts", Debugger::findScripts, 1, 0),
    JS_FN("findObjects", Debugger::findObjects, 1, 0),
    JS_FN("findAllGlobals", Debugger::findAllGlobals, 0, 0),
    JS_FN("makeGlobalObjectReference", Debugger::makeGlobalObjectReference, 1, 0),
#ifdef JS_TRACE_LOGGING
    JS_FN("setupTraceLoggerScriptCalls", Debugger::setupTraceLoggerScriptCalls, 0, 0),
    JS_FN("drainTraceLoggerScriptCalls", Debugger::drainTraceLoggerScriptCalls, 0, 0),
    JS_FN("startTraceLogger", Debugger::startTraceLogger, 0, 0),
    JS_FN("endTraceLogger", Debugger::endTraceLogger, 0, 0),
# ifdef NIGHTLY_BUILD
    JS_FN("setupTraceLogger", Debugger::setupTraceLogger, 1, 0),
    JS_FN("drainTraceLogger", Debugger::drainTraceLogger, 0, 0),
# endif
#endif
    JS_FS_END
};


/*** Debugger.Script *****************************************************************************/

static inline JSScript*
GetScriptReferent(JSObject* obj)
{
    MOZ_ASSERT(obj->getClass() == &DebuggerScript_class);
    return static_cast<JSScript*>(obj->as<NativeObject>().getPrivate());
}

void
DebuggerScript_trace(JSTracer* trc, JSObject* obj)
{
    /* This comes from a private pointer, so no barrier needed. */
    if (JSScript* script = GetScriptReferent(obj)) {
        TraceManuallyBarrieredCrossCompartmentEdge(trc, obj, &script, "Debugger.Script referent");
        obj->as<NativeObject>().setPrivateUnbarriered(script);
    }
}

const Class DebuggerScript_class = {
    "Script",
    JSCLASS_HAS_PRIVATE |
    JSCLASS_HAS_RESERVED_SLOTS(JSSLOT_DEBUGSCRIPT_COUNT),
    nullptr, nullptr, nullptr, nullptr, nullptr,
    nullptr, nullptr, nullptr, nullptr,
    nullptr,              /* call        */
    nullptr,              /* hasInstance */
    nullptr,              /* construct   */
    DebuggerScript_trace
};

JSObject*
Debugger::newDebuggerScript(JSContext* cx, HandleScript script)
{
    assertSameCompartment(cx, object.get());

    RootedObject proto(cx, &object->getReservedSlot(JSSLOT_DEBUG_SCRIPT_PROTO).toObject());
    MOZ_ASSERT(proto);
    NativeObject* scriptobj = NewNativeObjectWithGivenProto(cx, &DebuggerScript_class,
                                                            proto, TenuredObject);
    if (!scriptobj)
        return nullptr;
    scriptobj->setReservedSlot(JSSLOT_DEBUGSCRIPT_OWNER, ObjectValue(*object));
    scriptobj->setPrivateGCThing(script);

    return scriptobj;
}

JSObject*
Debugger::wrapScript(JSContext* cx, HandleScript script)
{
    assertSameCompartment(cx, object.get());
    MOZ_ASSERT(cx->compartment() != script->compartment());
    DependentAddPtr<ScriptWeakMap> p(cx, scripts, script);
    if (!p) {
        JSObject* scriptobj = newDebuggerScript(cx, script);
        if (!scriptobj)
            return nullptr;

        if (!p.add(cx, scripts, script, scriptobj))
            return nullptr;

        CrossCompartmentKey key(CrossCompartmentKey::DebuggerScript, object, script);
        if (!object->compartment()->putWrapper(cx, key, ObjectValue(*scriptobj))) {
            scripts.remove(script);
            ReportOutOfMemory(cx);
            return nullptr;
        }
    }

    MOZ_ASSERT(GetScriptReferent(p->value()) == script);
    return p->value();
}

static JSObject*
DebuggerScript_check(JSContext* cx, const Value& v, const char* clsname, const char* fnname)
{
    JSObject* thisobj = NonNullObject(cx, v);
    if (!thisobj)
        return nullptr;
    if (thisobj->getClass() != &DebuggerScript_class) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             clsname, fnname, thisobj->getClass()->name);
        return nullptr;
    }

    /*
     * Check for Debugger.Script.prototype, which is of class DebuggerScript_class
     * but whose script is null.
     */
    if (!GetScriptReferent(thisobj)) {
        MOZ_ASSERT(!GetScriptReferent(thisobj));
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             clsname, fnname, "prototype object");
        return nullptr;
    }

    return thisobj;
}

static JSObject*
DebuggerScript_checkThis(JSContext* cx, const CallArgs& args, const char* fnname)
{
    return DebuggerScript_check(cx, args.thisv(), "Debugger.Script", fnname);
}

#define THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, fnname, args, obj, script)            \
    CallArgs args = CallArgsFromVp(argc, vp);                                       \
    RootedObject obj(cx, DebuggerScript_checkThis(cx, args, fnname));               \
    if (!obj)                                                                       \
        return false;                                                               \
    Rooted<JSScript*> script(cx, GetScriptReferent(obj))

static bool
DebuggerScript_getDisplayName(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "(get displayName)", args, obj, script);
    Debugger* dbg = Debugger::fromChildJSObject(obj);

    JSFunction* func = script->functionNonDelazifying();
    JSString* name = func ? func->displayAtom() : nullptr;
    if (!name) {
        args.rval().setUndefined();
        return true;
    }

    RootedValue namev(cx, StringValue(name));
    if (!dbg->wrapDebuggeeValue(cx, &namev))
        return false;
    args.rval().set(namev);
    return true;
}

static bool
DebuggerScript_getUrl(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "(get url)", args, obj, script);

    if (script->filename()) {
        JSString* str;
        if (script->scriptSource()->introducerFilename())
            str = NewStringCopyZ<CanGC>(cx, script->scriptSource()->introducerFilename());
        else
            str = NewStringCopyZ<CanGC>(cx, script->filename());
        if (!str)
            return false;
        args.rval().setString(str);
    } else {
        args.rval().setNull();
    }
    return true;
}

static bool
DebuggerScript_getStartLine(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "(get startLine)", args, obj, script);
    args.rval().setNumber(uint32_t(script->lineno()));
    return true;
}

static bool
DebuggerScript_getLineCount(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "(get lineCount)", args, obj, script);

    unsigned maxLine = GetScriptLineExtent(script);
    args.rval().setNumber(double(maxLine));
    return true;
}

static bool
DebuggerScript_getSource(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "(get source)", args, obj, script);
    Debugger* dbg = Debugger::fromChildJSObject(obj);

    RootedScriptSource source(cx, &UncheckedUnwrap(script->sourceObject())->as<ScriptSourceObject>());
    RootedObject sourceObject(cx, dbg->wrapSource(cx, source));
    if (!sourceObject)
        return false;

    args.rval().setObject(*sourceObject);
    return true;
}

static bool
DebuggerScript_getSourceStart(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "(get sourceStart)", args, obj, script);
    args.rval().setNumber(uint32_t(script->sourceStart()));
    return true;
}

static bool
DebuggerScript_getSourceLength(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "(get sourceEnd)", args, obj, script);
    args.rval().setNumber(uint32_t(script->sourceEnd() - script->sourceStart()));
    return true;
}

static bool
DebuggerScript_getGlobal(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "(get global)", args, obj, script);
    Debugger* dbg = Debugger::fromChildJSObject(obj);

    RootedValue v(cx, ObjectValue(script->global()));
    if (!dbg->wrapDebuggeeValue(cx, &v))
        return false;
    args.rval().set(v);
    return true;
}

static bool
DebuggerScript_getChildScripts(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "getChildScripts", args, obj, script);
    Debugger* dbg = Debugger::fromChildJSObject(obj);

    RootedObject result(cx, NewDenseEmptyArray(cx));
    if (!result)
        return false;
    if (script->hasObjects()) {
        /*
         * script->savedCallerFun indicates that this is a direct eval script
         * and the calling function is stored as script->objects()->vector[0].
         * It is not really a child script of this script, so skip it using
         * innerObjectsStart().
         */
        ObjectArray* objects = script->objects();
        RootedFunction fun(cx);
        RootedScript funScript(cx);
        RootedObject obj(cx), s(cx);
        for (uint32_t i = script->innerObjectsStart(); i < objects->length; i++) {
            obj = objects->vector[i];
            if (obj->is<JSFunction>()) {
                fun = &obj->as<JSFunction>();
                // The inner function could be an asm.js native.
                if (fun->isNative())
                    continue;
                funScript = GetOrCreateFunctionScript(cx, fun);
                if (!funScript)
                    return false;
                s = dbg->wrapScript(cx, funScript);
                if (!s || !NewbornArrayPush(cx, result, ObjectValue(*s)))
                    return false;
            }
        }
    }
    args.rval().setObject(*result);
    return true;
}

static bool
ScriptOffset(JSContext* cx, JSScript* script, const Value& v, size_t* offsetp)
{
    double d;
    size_t off;

    bool ok = v.isNumber();
    if (ok) {
        d = v.toNumber();
        off = size_t(d);
    }
    if (!ok || off != d || !IsValidBytecodeOffset(cx, script, off)) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_BAD_OFFSET);
        return false;
    }
    *offsetp = off;
    return true;
}

static bool
DebuggerScript_getOffsetLine(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "getOffsetLine", args, obj, script);
    if (!args.requireAtLeast(cx, "Debugger.Script.getOffsetLine", 1))
        return false;
    size_t offset;
    if (!ScriptOffset(cx, script, args[0], &offset))
        return false;
    unsigned lineno = PCToLineNumber(script, script->offsetToPC(offset));
    args.rval().setNumber(lineno);
    return true;
}

namespace {

class BytecodeRangeWithPosition : private BytecodeRange
{
  public:
    using BytecodeRange::empty;
    using BytecodeRange::frontPC;
    using BytecodeRange::frontOpcode;
    using BytecodeRange::frontOffset;

    BytecodeRangeWithPosition(JSContext* cx, JSScript* script)
      : BytecodeRange(cx, script), lineno(script->lineno()), column(0),
        sn(script->notes()), snpc(script->code())
    {
        if (!SN_IS_TERMINATOR(sn))
            snpc += SN_DELTA(sn);
        updatePosition();
        while (frontPC() != script->main())
            popFront();
    }

    void popFront() {
        BytecodeRange::popFront();
        if (!empty())
            updatePosition();
    }

    size_t frontLineNumber() const { return lineno; }
    size_t frontColumnNumber() const { return column; }

  private:
    void updatePosition() {
        /*
         * Determine the current line number by reading all source notes up to
         * and including the current offset.
         */
        while (!SN_IS_TERMINATOR(sn) && snpc <= frontPC()) {
            SrcNoteType type = (SrcNoteType) SN_TYPE(sn);
            if (type == SRC_COLSPAN) {
                ptrdiff_t colspan = SN_OFFSET_TO_COLSPAN(GetSrcNoteOffset(sn, 0));
                MOZ_ASSERT(ptrdiff_t(column) + colspan >= 0);
                column += colspan;
            } if (type == SRC_SETLINE) {
                lineno = size_t(GetSrcNoteOffset(sn, 0));
                column = 0;
            } else if (type == SRC_NEWLINE) {
                lineno++;
                column = 0;
            }

            sn = SN_NEXT(sn);
            snpc += SN_DELTA(sn);
        }
    }

    size_t lineno;
    size_t column;
    jssrcnote* sn;
    jsbytecode* snpc;
};

/*
 * FlowGraphSummary::populate(cx, script) computes a summary of script's
 * control flow graph used by DebuggerScript_{getAllOffsets,getLineOffsets}.
 *
 * An instruction on a given line is an entry point for that line if it can be
 * reached from (an instruction on) a different line. We distinguish between the
 * following cases:
 *   - hasNoEdges:
 *       The instruction cannot be reached, so the instruction is not an entry
 *       point for the line it is on.
 *   - hasSingleEdge:
 *   - hasMultipleEdgesFromSingleLine:
 *       The instruction can be reached from a single line. If this line is
 *       different from the line the instruction is on, the instruction is an
 *       entry point for that line.
 *   - hasMultipleEdgesFromMultipleLines:
 *       The instruction can be reached from multiple lines. At least one of
 *       these lines is guaranteed to be different from the line the instruction
 *       is on, so the instruction is an entry point for that line.
 *
 * Similarly, an instruction on a given position (line/column pair) is an
 * entry point for that position if it can be reached from (an instruction on) a
 * different position. Again, we distinguish between the following cases:
 *   - hasNoEdges:
 *       The instruction cannot be reached, so the instruction is not an entry
 *       point for the position it is on.
 *   - hasSingleEdge:
 *       The instruction can be reached from a single position. If this line is
 *       different from the position the instruction is on, the instruction is
 *       an entry point for that position.
 *   - hasMultipleEdgesFromSingleLine:
 *   - hasMultipleEdgesFromMultipleLines:
 *       The instruction can be reached from multiple positions. At least one
 *       of these positions is guaranteed to be different from the position the
 *       instruction is on, so the instruction is an entry point for that
 *       position.
 */
class FlowGraphSummary {
  public:
    class Entry {
      public:
        static Entry createWithNoEdges() {
            return Entry(SIZE_MAX, 0);
        }

        static Entry createWithSingleEdge(size_t lineno, size_t column) {
            return Entry(lineno, column);
        }

        static Entry createWithMultipleEdgesFromSingleLine(size_t lineno) {
            return Entry(lineno, SIZE_MAX);
        }

        static Entry createWithMultipleEdgesFromMultipleLines() {
            return Entry(SIZE_MAX, SIZE_MAX);
        }

        Entry() {}

        bool hasNoEdges() const {
            return lineno_ == SIZE_MAX && column_ != SIZE_MAX;
        }

        bool hasSingleEdge() const {
            return lineno_ != SIZE_MAX && column_ != SIZE_MAX;
        }

        bool hasMultipleEdgesFromSingleLine() const {
            return lineno_ != SIZE_MAX && column_ == SIZE_MAX;
        }

        bool hasMultipleEdgesFromMultipleLines() const {
            return lineno_ == SIZE_MAX && column_ == SIZE_MAX;
        }

        bool operator==(const Entry& other) const {
            return lineno_ == other.lineno_ && column_ == other.column_;
        }

        bool operator!=(const Entry& other) const {
            return lineno_ != other.lineno_ || column_ != other.column_;
        }

        size_t lineno() const {
            return lineno_;
        }

        size_t column() const {
            return column_;
        }

      private:
        Entry(size_t lineno, size_t column) : lineno_(lineno), column_(column) {}

        size_t lineno_;
        size_t column_;
    };

    explicit FlowGraphSummary(JSContext* cx) : entries_(cx) {}

    Entry& operator[](size_t index) {
        return entries_[index];
    }

    bool populate(JSContext* cx, JSScript* script) {
        if (!entries_.growBy(script->length()))
            return false;
        unsigned mainOffset = script->pcToOffset(script->main());
        entries_[mainOffset] = Entry::createWithMultipleEdgesFromMultipleLines();
        for (size_t i = mainOffset + 1; i < script->length(); i++)
            entries_[i] = Entry::createWithNoEdges();

        size_t prevLineno = script->lineno();
        size_t prevColumn = 0;
        JSOp prevOp = JSOP_NOP;
        for (BytecodeRangeWithPosition r(cx, script); !r.empty(); r.popFront()) {
            size_t lineno = r.frontLineNumber();
            size_t column = r.frontColumnNumber();
            JSOp op = r.frontOpcode();

            if (FlowsIntoNext(prevOp))
                addEdge(prevLineno, prevColumn, r.frontOffset());

            if (js_CodeSpec[op].type() == JOF_JUMP) {
                addEdge(lineno, column, r.frontOffset() + GET_JUMP_OFFSET(r.frontPC()));
            } else if (op == JSOP_TABLESWITCH) {
                jsbytecode* pc = r.frontPC();
                size_t offset = r.frontOffset();
                ptrdiff_t step = JUMP_OFFSET_LEN;
                size_t defaultOffset = offset + GET_JUMP_OFFSET(pc);
                pc += step;
                addEdge(lineno, column, defaultOffset);

                int32_t low = GET_JUMP_OFFSET(pc);
                pc += JUMP_OFFSET_LEN;
                int ncases = GET_JUMP_OFFSET(pc) - low + 1;
                pc += JUMP_OFFSET_LEN;

                for (int i = 0; i < ncases; i++) {
                    size_t target = offset + GET_JUMP_OFFSET(pc);
                    addEdge(lineno, column, target);
                    pc += step;
                }
            }

            prevLineno = lineno;
            prevColumn = column;
            prevOp = op;
        }

        return true;
    }

  private:
    void addEdge(size_t sourceLineno, size_t sourceColumn, size_t targetOffset) {
        if (entries_[targetOffset].hasNoEdges())
            entries_[targetOffset] = Entry::createWithSingleEdge(sourceLineno, sourceColumn);
        else if (entries_[targetOffset].lineno() != sourceLineno)
            entries_[targetOffset] = Entry::createWithMultipleEdgesFromMultipleLines();
        else if (entries_[targetOffset].column() != sourceColumn)
            entries_[targetOffset] = Entry::createWithMultipleEdgesFromSingleLine(sourceLineno);
    }

    Vector<Entry> entries_;
};

} /* anonymous namespace */

static bool
DebuggerScript_getAllOffsets(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "getAllOffsets", args, obj, script);

    /*
     * First pass: determine which offsets in this script are jump targets and
     * which line numbers jump to them.
     */
    FlowGraphSummary flowData(cx);
    if (!flowData.populate(cx, script))
        return false;

    /* Second pass: build the result array. */
    RootedObject result(cx, NewDenseEmptyArray(cx));
    if (!result)
        return false;
    for (BytecodeRangeWithPosition r(cx, script); !r.empty(); r.popFront()) {
        size_t offset = r.frontOffset();
        size_t lineno = r.frontLineNumber();

        /* Make a note, if the current instruction is an entry point for the current line. */
        if (!flowData[offset].hasNoEdges() && flowData[offset].lineno() != lineno) {
            /* Get the offsets array for this line. */
            RootedObject offsets(cx);
            RootedValue offsetsv(cx);

            RootedId id(cx, INT_TO_JSID(lineno));

            bool found;
            if (!HasOwnProperty(cx, result, id, &found))
                return false;
            if (found && !GetProperty(cx, result, result, id, &offsetsv))
                return false;

            if (offsetsv.isObject()) {
                offsets = &offsetsv.toObject();
            } else {
                MOZ_ASSERT(offsetsv.isUndefined());

                /*
                 * Create an empty offsets array for this line.
                 * Store it in the result array.
                 */
                RootedId id(cx);
                RootedValue v(cx, NumberValue(lineno));
                offsets = NewDenseEmptyArray(cx);
                if (!offsets ||
                    !ValueToId<CanGC>(cx, v, &id))
                {
                    return false;
                }

                RootedValue value(cx, ObjectValue(*offsets));
                if (!DefineProperty(cx, result, id, value))
                    return false;
            }

            /* Append the current offset to the offsets array. */
            if (!NewbornArrayPush(cx, offsets, NumberValue(offset)))
                return false;
        }
    }

    args.rval().setObject(*result);
    return true;
}

static bool
DebuggerScript_getAllColumnOffsets(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "getAllColumnOffsets", args, obj, script);

    /*
     * First pass: determine which offsets in this script are jump targets and
     * which positions jump to them.
     */
    FlowGraphSummary flowData(cx);
    if (!flowData.populate(cx, script))
        return false;

    /* Second pass: build the result array. */
    RootedObject result(cx, NewDenseEmptyArray(cx));
    if (!result)
        return false;
    for (BytecodeRangeWithPosition r(cx, script); !r.empty(); r.popFront()) {
        size_t lineno = r.frontLineNumber();
        size_t column = r.frontColumnNumber();
        size_t offset = r.frontOffset();

        /* Make a note, if the current instruction is an entry point for the current position. */
        if (!flowData[offset].hasNoEdges() &&
            (flowData[offset].lineno() != lineno ||
             flowData[offset].column() != column)) {
            RootedPlainObject entry(cx, NewBuiltinClassInstance<PlainObject>(cx));
            if (!entry)
                return false;

            RootedId id(cx, NameToId(cx->names().lineNumber));
            RootedValue value(cx, NumberValue(lineno));
            if (!DefineProperty(cx, entry, id, value))
                return false;

            value = NumberValue(column);
            if (!DefineProperty(cx, entry, cx->names().columnNumber, value))
                return false;

            id = NameToId(cx->names().offset);
            value = NumberValue(offset);
            if (!DefineProperty(cx, entry, id, value))
                return false;

            if (!NewbornArrayPush(cx, result, ObjectValue(*entry)))
                return false;
        }
    }

    args.rval().setObject(*result);
    return true;
}

static bool
DebuggerScript_getLineOffsets(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "getLineOffsets", args, obj, script);
    if (!args.requireAtLeast(cx, "Debugger.Script.getLineOffsets", 1))
        return false;

    /* Parse lineno argument. */
    RootedValue linenoValue(cx, args[0]);
    size_t lineno;
    if (!ToNumber(cx, &linenoValue))
        return false;
    {
        double d = linenoValue.toNumber();
        lineno = size_t(d);
        if (lineno != d) {
            JS_ReportErrorNumber(cx,  GetErrorMessage, nullptr, JSMSG_DEBUG_BAD_LINE);
            return false;
        }
    }

    /*
     * First pass: determine which offsets in this script are jump targets and
     * which line numbers jump to them.
     */
    FlowGraphSummary flowData(cx);
    if (!flowData.populate(cx, script))
        return false;

    /* Second pass: build the result array. */
    RootedObject result(cx, NewDenseEmptyArray(cx));
    if (!result)
        return false;
    for (BytecodeRangeWithPosition r(cx, script); !r.empty(); r.popFront()) {
        size_t offset = r.frontOffset();

        /* If the op at offset is an entry point, append offset to result. */
        if (r.frontLineNumber() == lineno &&
            !flowData[offset].hasNoEdges() &&
            flowData[offset].lineno() != lineno)
        {
            if (!NewbornArrayPush(cx, result, NumberValue(offset)))
                return false;
        }
    }

    args.rval().setObject(*result);
    return true;
}

bool
Debugger::observesFrame(AbstractFramePtr frame) const
{
    return observesScript(frame.script());
}

bool
Debugger::observesFrame(const ScriptFrameIter& iter) const
{
    return observesScript(iter.script());
}

bool
Debugger::observesScript(JSScript* script) const
{
    if (!enabled)
        return false;
    return observesGlobal(&script->global()) && (!script->selfHosted() ||
                                                 SelfHostedFramesVisible());
}

/* static */ bool
Debugger::replaceFrameGuts(JSContext* cx, AbstractFramePtr from, AbstractFramePtr to,
                           ScriptFrameIter& iter)
{
    // Forward live Debugger.Frame objects.
    for (Debugger::FrameRange r(from); !r.empty(); r.popFront()) {
        RootedNativeObject frameobj(cx, r.frontFrame());
        Debugger* dbg = r.frontDebugger();
        MOZ_ASSERT(dbg == Debugger::fromChildJSObject(frameobj));

        // Update frame object's ScriptFrameIter::data pointer.
        DebuggerFrame_freeScriptFrameIterData(cx->runtime()->defaultFreeOp(), frameobj);
        ScriptFrameIter::Data* data = iter.copyData();
        if (!data)
            return false;
        frameobj->setPrivate(data);

        // Remove the old entry before mutating the HashMap.
        r.removeFrontFrame();

        // Add the frame object with |to| as key.
        if (!dbg->frames.putNew(to, frameobj)) {
            ReportOutOfMemory(cx);
            return false;
        }
    }

    // Rekey missingScopes to maintain Debugger.Environment identity and
    // forward liveScopes to point to the new frame, as the old frame will be
    // gone.
    DebugScopes::forwardLiveFrame(cx, from, to);

    return true;
}

/* static */ bool
Debugger::inFrameMaps(AbstractFramePtr frame)
{
    FrameRange r(frame);
    return !r.empty();
}

/* static */ void
Debugger::removeFromFrameMapsAndClearBreakpointsIn(JSContext* cx, AbstractFramePtr frame)
{
    Handle<GlobalObject*> global = cx->global();

    for (FrameRange r(frame, global); !r.empty(); r.popFront()) {
        RootedNativeObject frameobj(cx, r.frontFrame());
        Debugger* dbg = r.frontDebugger();
        MOZ_ASSERT(dbg == Debugger::fromChildJSObject(frameobj));

        FreeOp* fop = cx->runtime()->defaultFreeOp();
        DebuggerFrame_freeScriptFrameIterData(fop, frameobj);
        DebuggerFrame_maybeDecrementFrameScriptStepModeCount(fop, frame, frameobj);

        dbg->frames.remove(frame);
    }

    /*
     * If this is an eval frame, then from the debugger's perspective the
     * script is about to be destroyed. Remove any breakpoints in it.
     */
    if (frame.isEvalFrame()) {
        RootedScript script(cx, frame.script());
        script->clearBreakpointsIn(cx->runtime()->defaultFreeOp(), nullptr, nullptr);
    }
}

/* static */ bool
Debugger::handleBaselineOsr(JSContext* cx, InterpreterFrame* from, jit::BaselineFrame* to)
{
    ScriptFrameIter iter(cx);
    MOZ_ASSERT(iter.abstractFramePtr() == to);
    return replaceFrameGuts(cx, from, to, iter);
}

/* static */ bool
Debugger::handleIonBailout(JSContext* cx, jit::RematerializedFrame* from, jit::BaselineFrame* to)
{
    // When we return to a bailed-out Ion real frame, we must update all
    // Debugger.Frames that refer to its inline frames. However, since we
    // can't pop individual inline frames off the stack (we can only pop the
    // real frame that contains them all, as a unit), we cannot assume that
    // the frame we're dealing with is the top frame. Advance the iterator
    // across any inlined frames younger than |to|, the baseline frame
    // reconstructed during bailout from the Ion frame corresponding to
    // |from|.
    ScriptFrameIter iter(cx);
    while (iter.abstractFramePtr() != to)
        ++iter;
    return replaceFrameGuts(cx, from, to, iter);
}

/* static */ void
Debugger::handleUnrecoverableIonBailoutError(JSContext* cx, jit::RematerializedFrame* frame)
{
    // Ion bailout can fail due to overrecursion. In such cases we cannot
    // honor any further Debugger hooks on the frame, and need to ensure that
    // its Debugger.Frame entry is cleaned up.
    removeFromFrameMapsAndClearBreakpointsIn(cx, frame);
}

/* static */ void
Debugger::propagateForcedReturn(JSContext* cx, AbstractFramePtr frame, HandleValue rval)
{
    // Invoking the interrupt handler is considered a step and invokes the
    // youngest frame's onStep handler, if any. However, we cannot handle
    // { return: ... } resumption values straightforwardly from the interrupt
    // handler. Instead, we set the intended return value in the frame's rval
    // slot and set the propagating-forced-return flag on the JSContext.
    //
    // The interrupt handler then returns false with no exception set,
    // signaling an uncatchable exception. In the exception handlers, we then
    // check for the special propagating-forced-return flag.
    MOZ_ASSERT(!cx->isExceptionPending());
    cx->setPropagatingForcedReturn();
    frame.setReturnValue(rval);
}

static bool
DebuggerScript_setBreakpoint(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "setBreakpoint", args, obj, script);
    if (!args.requireAtLeast(cx, "Debugger.Script.setBreakpoint", 2))
        return false;
    Debugger* dbg = Debugger::fromChildJSObject(obj);

    if (!dbg->observesScript(script)) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_NOT_DEBUGGING);
        return false;
    }

    size_t offset;
    if (!ScriptOffset(cx, script, args[0], &offset))
        return false;

    RootedObject handler(cx, NonNullObject(cx, args[1]));
    if (!handler)
        return false;

    // Ensure observability *before* setting the breakpoint. If the script is
    // not already a debuggee, trying to ensure observability after setting
    // the breakpoint (and thus marking the script as a debuggee) will skip
    // actually ensuring observability.
    if (!dbg->ensureExecutionObservabilityOfScript(cx, script))
        return false;

    jsbytecode* pc = script->offsetToPC(offset);
    BreakpointSite* site = script->getOrCreateBreakpointSite(cx, pc);
    if (!site)
        return false;
    site->inc(cx->runtime()->defaultFreeOp());
    if (cx->runtime()->new_<Breakpoint>(dbg, site, handler)) {
        args.rval().setUndefined();
        return true;
    }
    site->dec(cx->runtime()->defaultFreeOp());
    site->destroyIfEmpty(cx->runtime()->defaultFreeOp());
    return false;
}

static bool
DebuggerScript_getBreakpoints(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "getBreakpoints", args, obj, script);
    Debugger* dbg = Debugger::fromChildJSObject(obj);

    jsbytecode* pc;
    if (args.length() > 0) {
        size_t offset;
        if (!ScriptOffset(cx, script, args[0], &offset))
            return false;
        pc = script->offsetToPC(offset);
    } else {
        pc = nullptr;
    }

    RootedObject arr(cx, NewDenseEmptyArray(cx));
    if (!arr)
        return false;

    for (unsigned i = 0; i < script->length(); i++) {
        BreakpointSite* site = script->getBreakpointSite(script->offsetToPC(i));
        if (site && (!pc || site->pc == pc)) {
            for (Breakpoint* bp = site->firstBreakpoint(); bp; bp = bp->nextInSite()) {
                if (bp->debugger == dbg &&
                    !NewbornArrayPush(cx, arr, ObjectValue(*bp->getHandler())))
                {
                    return false;
                }
            }
        }
    }
    args.rval().setObject(*arr);
    return true;
}

static bool
DebuggerScript_clearBreakpoint(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "clearBreakpoint", args, obj, script);
    if (!args.requireAtLeast(cx, "Debugger.Script.clearBreakpoint", 1))
        return false;
    Debugger* dbg = Debugger::fromChildJSObject(obj);

    JSObject* handler = NonNullObject(cx, args[0]);
    if (!handler)
        return false;

    script->clearBreakpointsIn(cx->runtime()->defaultFreeOp(), dbg, handler);
    args.rval().setUndefined();
    return true;
}

static bool
DebuggerScript_clearAllBreakpoints(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "clearAllBreakpoints", args, obj, script);
    Debugger* dbg = Debugger::fromChildJSObject(obj);
    script->clearBreakpointsIn(cx->runtime()->defaultFreeOp(), dbg, nullptr);
    args.rval().setUndefined();
    return true;
}

static bool
DebuggerScript_isInCatchScope(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "isInCatchScope", args, obj, script);
    if (!args.requireAtLeast(cx, "Debugger.Script.isInCatchScope", 1))
        return false;

    size_t offset;
    if (!ScriptOffset(cx, script, args[0], &offset))
        return false;

    /*
     * Try note ranges are relative to the mainOffset of the script, so adjust
     * offset accordingly.
     */
    offset -= script->mainOffset();

    args.rval().setBoolean(false);
    if (script->hasTrynotes()) {
        JSTryNote* tnBegin = script->trynotes()->vector;
        JSTryNote* tnEnd = tnBegin + script->trynotes()->length;
        while (tnBegin != tnEnd) {
            if (tnBegin->start <= offset &&
                offset <= tnBegin->start + tnBegin->length &&
                tnBegin->kind == JSTRY_CATCH)
            {
                args.rval().setBoolean(true);
                break;
            }
            ++tnBegin;
        }
    }
    return true;
}

static bool
DebuggerScript_getOffsetsCoverage(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSCRIPT_SCRIPT(cx, argc, vp, "getOffsetsCoverage", args, obj, script);

    // If the script has no coverage information, then skip this and return null
    // instead.
    if (!script->hasScriptCounts()) {
        args.rval().setNull();
        return true;
    }

    ScriptCounts* sc = &script->getScriptCounts();

    // If the main ever got visited, then assume that any code before main got
    // visited once.
    uint64_t hits = 0;
    const PCCounts* counts = sc->maybeGetPCCounts(script->pcToOffset(script->main()));
    if (counts->numExec())
        hits = 1;

    // Build an array of objects which are composed of 4 properties:
    //  - offset          PC offset of the current opcode.
    //  - lineNumber      Line of the current opcode.
    //  - columnNumber    Column of the current opcode.
    //  - count           Number of times the instruction got executed.
    RootedObject result(cx, NewDenseEmptyArray(cx));
    if (!result)
        return false;

    RootedId offsetId(cx, AtomToId(cx->names().offset));
    RootedId lineNumberId(cx, AtomToId(cx->names().lineNumber));
    RootedId columnNumberId(cx, AtomToId(cx->names().columnNumber));
    RootedId countId(cx, AtomToId(cx->names().count));

    RootedObject item(cx);
    RootedValue offsetValue(cx);
    RootedValue lineNumberValue(cx);
    RootedValue columnNumberValue(cx);
    RootedValue countValue(cx);

    // Iterate linearly over the bytecode.
    for (BytecodeRangeWithPosition r(cx, script); !r.empty(); r.popFront()) {
        size_t offset = r.frontOffset();

        // The beginning of each non-branching sequences of instruction set the
        // number of execution of the current instruction and any following
        // instruction.
        counts = sc->maybeGetPCCounts(offset);
        if (counts)
            hits = counts->numExec();

        offsetValue.setNumber(double(offset));
        lineNumberValue.setNumber(double(r.frontLineNumber()));
        columnNumberValue.setNumber(double(r.frontColumnNumber()));
        countValue.setNumber(double(hits));

        // Create a new object with the offset, line number, column number, the
        // number of hit counts, and append it to the array.
        item = NewObjectWithGivenProto<PlainObject>(cx, nullptr);
        if (!item ||
            !DefineProperty(cx, item, offsetId, offsetValue) ||
            !DefineProperty(cx, item, lineNumberId, lineNumberValue) ||
            !DefineProperty(cx, item, columnNumberId, columnNumberValue) ||
            !DefineProperty(cx, item, countId, countValue) ||
            !NewbornArrayPush(cx, result, ObjectValue(*item)))
        {
            return false;
        }

        // If the current instruction has thrown, then decrement the hit counts
        // with the number of throws.
        counts = sc->maybeGetThrowCounts(offset);
        if (counts)
            hits -= counts->numExec();
    }

    args.rval().setObject(*result);
    return true;
}

static bool
DebuggerScript_construct(JSContext* cx, unsigned argc, Value* vp)
{
    JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NO_CONSTRUCTOR,
                         "Debugger.Script");
    return false;
}

static const JSPropertySpec DebuggerScript_properties[] = {
    JS_PSG("displayName", DebuggerScript_getDisplayName, 0),
    JS_PSG("url", DebuggerScript_getUrl, 0),
    JS_PSG("startLine", DebuggerScript_getStartLine, 0),
    JS_PSG("lineCount", DebuggerScript_getLineCount, 0),
    JS_PSG("source", DebuggerScript_getSource, 0),
    JS_PSG("sourceStart", DebuggerScript_getSourceStart, 0),
    JS_PSG("sourceLength", DebuggerScript_getSourceLength, 0),
    JS_PSG("global", DebuggerScript_getGlobal, 0),
    JS_PS_END
};

static const JSFunctionSpec DebuggerScript_methods[] = {
    JS_FN("getChildScripts", DebuggerScript_getChildScripts, 0, 0),
    JS_FN("getAllOffsets", DebuggerScript_getAllOffsets, 0, 0),
    JS_FN("getAllColumnOffsets", DebuggerScript_getAllColumnOffsets, 0, 0),
    JS_FN("getLineOffsets", DebuggerScript_getLineOffsets, 1, 0),
    JS_FN("getOffsetLine", DebuggerScript_getOffsetLine, 0, 0),
    JS_FN("setBreakpoint", DebuggerScript_setBreakpoint, 2, 0),
    JS_FN("getBreakpoints", DebuggerScript_getBreakpoints, 1, 0),
    JS_FN("clearBreakpoint", DebuggerScript_clearBreakpoint, 1, 0),
    JS_FN("clearAllBreakpoints", DebuggerScript_clearAllBreakpoints, 0, 0),
    JS_FN("isInCatchScope", DebuggerScript_isInCatchScope, 1, 0),
    JS_FN("getOffsetsCoverage", DebuggerScript_getOffsetsCoverage, 0, 0),
    JS_FS_END
};


/*** Debugger.Source *****************************************************************************/

static inline ScriptSourceObject*
GetSourceReferent(JSObject* obj)
{
    MOZ_ASSERT(obj->getClass() == &DebuggerSource_class);
    return static_cast<ScriptSourceObject*>(obj->as<NativeObject>().getPrivate());
}

void
DebuggerSource_trace(JSTracer* trc, JSObject* obj)
{
    /*
     * There is a barrier on private pointers, so the Unbarriered marking
     * is okay.
     */
    if (JSObject* referent = GetSourceReferent(obj)) {
        TraceManuallyBarrieredCrossCompartmentEdge(trc, obj, &referent,
                                                   "Debugger.Source referent");
        obj->as<NativeObject>().setPrivateUnbarriered(referent);
    }
}

const Class DebuggerSource_class = {
    "Source",
    JSCLASS_HAS_PRIVATE |
    JSCLASS_HAS_RESERVED_SLOTS(JSSLOT_DEBUGSOURCE_COUNT),
    nullptr, nullptr, nullptr, nullptr, nullptr,
    nullptr, nullptr, nullptr, nullptr,
    nullptr,              /* call        */
    nullptr,              /* hasInstance */
    nullptr,              /* construct   */
    DebuggerSource_trace
};

JSObject*
Debugger::newDebuggerSource(JSContext* cx, HandleScriptSource source)
{
    assertSameCompartment(cx, object.get());

    RootedObject proto(cx, &object->getReservedSlot(JSSLOT_DEBUG_SOURCE_PROTO).toObject());
    MOZ_ASSERT(proto);
    NativeObject* sourceobj = NewNativeObjectWithGivenProto(cx, &DebuggerSource_class,
                                                            proto, TenuredObject);
    if (!sourceobj)
        return nullptr;
    sourceobj->setReservedSlot(JSSLOT_DEBUGSOURCE_OWNER, ObjectValue(*object));
    sourceobj->setPrivateGCThing(source);

    return sourceobj;
}

JSObject*
Debugger::wrapSource(JSContext* cx, HandleScriptSource source)
{
    assertSameCompartment(cx, object.get());
    MOZ_ASSERT(cx->compartment() != source->compartment());
    DependentAddPtr<SourceWeakMap> p(cx, sources, source);
    if (!p) {
        JSObject* sourceobj = newDebuggerSource(cx, source);
        if (!sourceobj)
            return nullptr;

        if (!p.add(cx, sources, source, sourceobj))
            return nullptr;

        CrossCompartmentKey key(CrossCompartmentKey::DebuggerSource, object, source);
        if (!object->compartment()->putWrapper(cx, key, ObjectValue(*sourceobj))) {
            sources.remove(source);
            ReportOutOfMemory(cx);
            return nullptr;
        }
    }

    MOZ_ASSERT(GetSourceReferent(p->value()) == source);
    return p->value();
}

static bool
DebuggerSource_construct(JSContext* cx, unsigned argc, Value* vp)
{
    JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NO_CONSTRUCTOR,
                         "Debugger.Source");
    return false;
}

static NativeObject*
DebuggerSource_checkThis(JSContext* cx, const CallArgs& args, const char* fnname)
{
    JSObject* thisobj = NonNullObject(cx, args.thisv());
    if (!thisobj)
        return nullptr;
    if (thisobj->getClass() != &DebuggerSource_class) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger.Source", fnname, thisobj->getClass()->name);
        return nullptr;
    }

    NativeObject* nthisobj = &thisobj->as<NativeObject>();

    if (!GetSourceReferent(thisobj)) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger.Frame", fnname, "prototype object");
        return nullptr;
    }

    return nthisobj;
}

#define THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, fnname, args, obj, sourceObject)    \
    CallArgs args = CallArgsFromVp(argc, vp);                                       \
    RootedNativeObject obj(cx, DebuggerSource_checkThis(cx, args, fnname));         \
    if (!obj)                                                                       \
        return false;                                                               \
    RootedScriptSource sourceObject(cx, GetSourceReferent(obj));                    \
    if (!sourceObject)                                                              \
        return false;

static bool
DebuggerSource_getText(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get text)", args, obj, sourceObject);
    Value textv = obj->getReservedSlot(JSSLOT_DEBUGSOURCE_TEXT);
    if (!textv.isUndefined()) {
        MOZ_ASSERT(textv.isString());
        args.rval().set(textv);
        return true;
    }

    ScriptSource* ss = sourceObject->source();
    bool hasSourceData = ss->hasSourceData();
    if (!ss->hasSourceData() && !JSScript::loadSource(cx, ss, &hasSourceData))
        return false;

    JSString* str = hasSourceData ? ss->substring(cx, 0, ss->length())
                                  : NewStringCopyZ<CanGC>(cx, "[no source]");
    if (!str)
        return false;

    args.rval().setString(str);
    obj->setReservedSlot(JSSLOT_DEBUGSOURCE_TEXT, args.rval());
    return true;
}

static bool
DebuggerSource_getUrl(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get url)", args, obj, sourceObject);

    ScriptSource* ss = sourceObject->source();
    if (ss->filename()) {
        JSString* str = NewStringCopyZ<CanGC>(cx, ss->filename());
        if (!str)
            return false;
        args.rval().setString(str);
    } else {
        args.rval().setNull();
    }
    return true;
}

static bool
DebuggerSource_getDisplayURL(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get url)", args, obj, sourceObject);

    ScriptSource* ss = sourceObject->source();
    MOZ_ASSERT(ss);

    if (ss->hasDisplayURL()) {
        JSString* str = JS_NewUCStringCopyZ(cx, ss->displayURL());
        if (!str)
            return false;
        args.rval().setString(str);
    } else {
        args.rval().setNull();
    }

    return true;
}

static bool
DebuggerSource_getElement(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get element)", args, obj, sourceObject);

    if (sourceObject->element()) {
        args.rval().setObjectOrNull(sourceObject->element());
        if (!Debugger::fromChildJSObject(obj)->wrapDebuggeeValue(cx, args.rval()))
            return false;
    } else {
        args.rval().setUndefined();
    }
    return true;
}

static bool
DebuggerSource_getElementProperty(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get elementAttributeName)", args, obj, sourceObject);
    args.rval().set(sourceObject->elementAttributeName());
    return Debugger::fromChildJSObject(obj)->wrapDebuggeeValue(cx, args.rval());
}

static bool
DebuggerSource_getIntroductionScript(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get introductionScript)", args, obj, sourceObject);

    RootedScript script(cx, sourceObject->introductionScript());
    if (script) {
        RootedObject scriptDO(cx, Debugger::fromChildJSObject(obj)->wrapScript(cx, script));
        if (!scriptDO)
            return false;
        args.rval().setObject(*scriptDO);
    } else {
        args.rval().setUndefined();
    }
    return true;
}

static bool
DebuggerSource_getIntroductionOffset(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get introductionOffset)", args, obj, sourceObject);

    // Regardless of what's recorded in the ScriptSourceObject and
    // ScriptSource, only hand out the introduction offset if we also have
    // the script within which it applies.
    ScriptSource* ss = sourceObject->source();
    if (ss->hasIntroductionOffset() && sourceObject->introductionScript())
        args.rval().setInt32(ss->introductionOffset());
    else
        args.rval().setUndefined();
    return true;
}

static bool
DebuggerSource_getIntroductionType(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get introductionType)", args, obj, sourceObject);

    ScriptSource* ss = sourceObject->source();
    if (ss->hasIntroductionType()) {
        JSString* str = NewStringCopyZ<CanGC>(cx, ss->introductionType());
        if (!str)
            return false;
        args.rval().setString(str);
    } else {
        args.rval().setUndefined();
    }
    return true;
}

static bool
DebuggerSource_setSourceMapUrl(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "sourceMapURL", args, obj, sourceObject);
    ScriptSource* ss = sourceObject->source();
    MOZ_ASSERT(ss);

    JSString* str = ToString<CanGC>(cx, args[0]);
    if (!str)
        return false;

    AutoStableStringChars stableChars(cx);
    if (!stableChars.initTwoByte(cx, str))
        return false;

    ss->setSourceMapURL(cx, stableChars.twoByteChars());
    args.rval().setUndefined();
    return true;
}

static bool
DebuggerSource_getSourceMapUrl(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get sourceMapURL)", args, obj, sourceObject);

    ScriptSource* ss = sourceObject->source();
    MOZ_ASSERT(ss);

    if (ss->hasSourceMapURL()) {
        JSString* str = JS_NewUCStringCopyZ(cx, ss->sourceMapURL());
        if (!str)
            return false;
        args.rval().setString(str);
    } else {
        args.rval().setNull();
    }

    return true;
}

static const JSPropertySpec DebuggerSource_properties[] = {
    JS_PSG("text", DebuggerSource_getText, 0),
    JS_PSG("url", DebuggerSource_getUrl, 0),
    JS_PSG("element", DebuggerSource_getElement, 0),
    JS_PSG("displayURL", DebuggerSource_getDisplayURL, 0),
    JS_PSG("introductionScript", DebuggerSource_getIntroductionScript, 0),
    JS_PSG("introductionOffset", DebuggerSource_getIntroductionOffset, 0),
    JS_PSG("introductionType", DebuggerSource_getIntroductionType, 0),
    JS_PSG("elementAttributeName", DebuggerSource_getElementProperty, 0),
    JS_PSGS("sourceMapURL", DebuggerSource_getSourceMapUrl, DebuggerSource_setSourceMapUrl, 0),
    JS_PS_END
};

static const JSFunctionSpec DebuggerSource_methods[] = {
    JS_FS_END
};


/*** Debugger.Frame ******************************************************************************/

static void
UpdateFrameIterPc(FrameIter& iter)
{
    if (iter.abstractFramePtr().isRematerializedFrame()) {
#ifdef DEBUG
        // Rematerialized frames don't need their pc updated. The reason we
        // need to update pc is because we might get the same Debugger.Frame
        // object for multiple re-entries into debugger code from debuggee
        // code. This reentrancy is not possible with rematerialized frames,
        // because when returning to debuggee code, we would have bailed out
        // to baseline.
        //
        // We walk the stack to assert that it doesn't need updating.
        jit::RematerializedFrame* frame = iter.abstractFramePtr().asRematerializedFrame();
        jit::JitFrameLayout* jsFrame = (jit::JitFrameLayout*)frame->top();
        jit::JitActivation* activation = iter.activation()->asJit();

        ActivationIterator activationIter(activation->cx()->runtime());
        while (activationIter.activation() != activation)
            ++activationIter;

        jit::JitFrameIterator jitIter(activationIter);
        while (!jitIter.isIonJS() || jitIter.jsFrame() != jsFrame)
            ++jitIter;

        jit::InlineFrameIterator ionInlineIter(activation->cx(), &jitIter);
        while (ionInlineIter.frameNo() != frame->frameNo())
            ++ionInlineIter;

        MOZ_ASSERT(ionInlineIter.pc() == iter.pc());
#endif
        return;
    }

    iter.updatePcQuadratic();
}

static void
DebuggerFrame_freeScriptFrameIterData(FreeOp* fop, JSObject* obj)
{
    AbstractFramePtr frame = AbstractFramePtr::FromRaw(obj->as<NativeObject>().getPrivate());
    if (frame.isScriptFrameIterData())
        fop->delete_((ScriptFrameIter::Data*) frame.raw());
    obj->as<NativeObject>().setPrivate(nullptr);
}

static void
DebuggerFrame_maybeDecrementFrameScriptStepModeCount(FreeOp* fop, AbstractFramePtr frame,
                                                     NativeObject* frameobj)
{
    /* If this frame has an onStep handler, decrement the script's count. */
    if (!frameobj->getReservedSlot(JSSLOT_DEBUGFRAME_ONSTEP_HANDLER).isUndefined())
        frame.script()->decrementStepModeCount(fop);
}

static void
DebuggerFrame_finalize(FreeOp* fop, JSObject* obj)
{
    DebuggerFrame_freeScriptFrameIterData(fop, obj);
}

const Class DebuggerFrame_class = {
    "Frame", JSCLASS_HAS_PRIVATE | JSCLASS_HAS_RESERVED_SLOTS(JSSLOT_DEBUGFRAME_COUNT),
    nullptr, nullptr, nullptr, nullptr, nullptr,
    nullptr, nullptr, nullptr, DebuggerFrame_finalize
};

static NativeObject*
CheckThisFrame(JSContext* cx, const CallArgs& args, const char* fnname, bool checkLive)
{
    JSObject* thisobj = NonNullObject(cx, args.thisv());
    if (!thisobj)
        return nullptr;
    if (thisobj->getClass() != &DebuggerFrame_class) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger.Frame", fnname, thisobj->getClass()->name);
        return nullptr;
    }

    NativeObject* nthisobj = &thisobj->as<NativeObject>();

    /*
     * Forbid Debugger.Frame.prototype, which is of class DebuggerFrame_class
     * but isn't really a working Debugger.Frame object. The prototype object
     * is distinguished by having a nullptr private value. Also, forbid popped
     * frames.
     */
    if (!nthisobj->getPrivate()) {
        if (nthisobj->getReservedSlot(JSSLOT_DEBUGFRAME_OWNER).isUndefined()) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                                 "Debugger.Frame", fnname, "prototype object");
            return nullptr;
        }
        if (checkLive) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_NOT_LIVE,
                                 "Debugger.Frame");
            return nullptr;
        }
    }
    return nthisobj;
}

/*
 * To make frequently fired hooks like onEnterFrame more performant,
 * Debugger.Frame methods should not create a ScriptFrameIter unless it
 * absolutely needs to. That is, unless the method has to call a method on
 * ScriptFrameIter that's otherwise not available on AbstractFramePtr.
 *
 * When a Debugger.Frame is first created, its private slot is set to the
 * AbstractFramePtr itself. The first time the users asks for a
 * ScriptFrameIter, we construct one, have it settle on the frame pointed to
 * by the AbstractFramePtr and cache its internal Data in the Debugger.Frame
 * object's private slot. Subsequent uses of the Debugger.Frame object will
 * always create a ScriptFrameIter from the cached Data.
 *
 * Methods that only need the AbstractFramePtr should use THIS_FRAME.
 * Methods that need a ScriptFrameIterator should use THIS_FRAME_ITER.
 */

#define THIS_FRAME_THISOBJ(cx, argc, vp, fnname, args, thisobj)                \
    CallArgs args = CallArgsFromVp(argc, vp);                                  \
    RootedNativeObject thisobj(cx, CheckThisFrame(cx, args, fnname, true));    \
    if (!thisobj)                                                              \
        return false

#define THIS_FRAME(cx, argc, vp, fnname, args, thisobj, frame)                 \
    THIS_FRAME_THISOBJ(cx, argc, vp, fnname, args, thisobj);                   \
    AbstractFramePtr frame = AbstractFramePtr::FromRaw(thisobj->getPrivate()); \
    if (frame.isScriptFrameIterData()) {                                       \
        ScriptFrameIter iter(*(ScriptFrameIter::Data*)(frame.raw()));          \
        frame = iter.abstractFramePtr();                                       \
    }

#define THIS_FRAME_ITER(cx, argc, vp, fnname, args, thisobj, maybeIter, iter)  \
    THIS_FRAME_THISOBJ(cx, argc, vp, fnname, args, thisobj);                   \
    Maybe<ScriptFrameIter> maybeIter;                                          \
    {                                                                          \
        AbstractFramePtr f = AbstractFramePtr::FromRaw(thisobj->getPrivate()); \
        if (f.isScriptFrameIterData()) {                                       \
            maybeIter.emplace(*(ScriptFrameIter::Data*)(f.raw()));             \
        } else {                                                               \
            maybeIter.emplace(cx, ScriptFrameIter::ALL_CONTEXTS,               \
                              ScriptFrameIter::GO_THROUGH_SAVED,               \
                              ScriptFrameIter::IGNORE_DEBUGGER_EVAL_PREV_LINK); \
            ScriptFrameIter& iter = *maybeIter;                                \
            while (!iter.hasUsableAbstractFramePtr() || iter.abstractFramePtr() != f) \
                ++iter;                                                        \
            AbstractFramePtr data = iter.copyDataAsAbstractFramePtr();         \
            if (!data)                                                         \
                return false;                                                  \
            thisobj->setPrivate(data.raw());                                   \
        }                                                                      \
    }                                                                          \
    ScriptFrameIter& iter = *maybeIter

#define THIS_FRAME_OWNER(cx, argc, vp, fnname, args, thisobj, frame, dbg)      \
    THIS_FRAME(cx, argc, vp, fnname, args, thisobj, frame);                    \
    Debugger* dbg = Debugger::fromChildJSObject(thisobj)

#define THIS_FRAME_OWNER_ITER(cx, argc, vp, fnname, args, thisobj, maybeIter, iter, dbg) \
    THIS_FRAME_ITER(cx, argc, vp, fnname, args, thisobj, maybeIter, iter);               \
    Debugger* dbg = Debugger::fromChildJSObject(thisobj)

static bool
DebuggerFrame_getType(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "get type", args, thisobj, frame);

    /*
     * Indirect eval frames are both isGlobalFrame() and isEvalFrame(), so the
     * order of checks here is significant.
     */
    args.rval().setString(frame.isEvalFrame()
                          ? cx->names().eval
                          : frame.isGlobalFrame()
                          ? cx->names().global
                          : cx->names().call);
    return true;
}

static bool
DebuggerFrame_getImplementation(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "get implementation", args, thisobj, frame);

    const char* s;
    if (frame.isBaselineFrame())
        s = "baseline";
    else if (frame.isRematerializedFrame())
        s = "ion";
    else
        s = "interpreter";

    JSAtom* str = Atomize(cx, s, strlen(s));
    if (!str)
        return false;

    args.rval().setString(str);
    return true;
}

static bool
DebuggerFrame_getEnvironment(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME_OWNER_ITER(cx, argc, vp, "get environment", args, thisobj, _, iter, dbg);

    Rooted<Env*> env(cx);
    {
        AutoCompartment ac(cx, iter.abstractFramePtr().scopeChain());
        UpdateFrameIterPc(iter);
        env = GetDebugScopeForFrame(cx, iter.abstractFramePtr(), iter.pc());
        if (!env)
            return false;
    }

    return dbg->wrapEnvironment(cx, env, args.rval());
}

static bool
DebuggerFrame_getCallee(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "get callee", args, thisobj, frame);
    RootedValue calleev(cx, frame.isNonEvalFunctionFrame() ? frame.calleev() : NullValue());
    if (!Debugger::fromChildJSObject(thisobj)->wrapDebuggeeValue(cx, &calleev))
        return false;
    args.rval().set(calleev);
    return true;
}

static bool
DebuggerFrame_getGenerator(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "get generator", args, thisobj, frame);
    args.rval().setBoolean(frame.script()->isGenerator());
    return true;
}

static bool
DebuggerFrame_getConstructing(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME_ITER(cx, argc, vp, "get constructing", args, thisobj, _, iter);
    args.rval().setBoolean(iter.isFunctionFrame() && iter.isConstructing());
    return true;
}

static bool
DebuggerFrame_getThis(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME_ITER(cx, argc, vp, "get this", args, thisobj, _, iter);
    RootedValue thisv(cx);
    {
        AutoCompartment ac(cx, iter.scopeChain(cx));
        if (!iter.computeThis(cx))
            return false;
        thisv = iter.computedThisValue();
    }
    if (!Debugger::fromChildJSObject(thisobj)->wrapDebuggeeValue(cx, &thisv))
        return false;
    args.rval().set(thisv);
    return true;
}

static bool
DebuggerFrame_getOlder(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME_ITER(cx, argc, vp, "get this", args, thisobj, _, iter);
    Debugger* dbg = Debugger::fromChildJSObject(thisobj);

    for (++iter; !iter.done(); ++iter) {
        if (dbg->observesFrame(iter)) {
            if (iter.isIon() && !iter.ensureHasRematerializedFrame(cx))
                return false;
            return dbg->getScriptFrame(cx, iter, args.rval());
        }
    }
    args.rval().setNull();
    return true;
}

const Class DebuggerArguments_class = {
    "Arguments", JSCLASS_HAS_RESERVED_SLOTS(JSSLOT_DEBUGARGUMENTS_COUNT)
};

/* The getter used for each element of frame.arguments. See DebuggerFrame_getArguments. */
static bool
DebuggerArguments_getArg(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);
    int32_t i = args.callee().as<JSFunction>().getExtendedSlot(0).toInt32();

    /* Check that the this value is an Arguments object. */
    RootedObject argsobj(cx, NonNullObject(cx, args.thisv()));
    if (!argsobj)
        return false;
    if (argsobj->getClass() != &DebuggerArguments_class) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Arguments", "getArgument", argsobj->getClass()->name);
        return false;
    }

    /*
     * Put the Debugger.Frame into the this-value slot, then use THIS_FRAME
     * to check that it is still live and get the fp.
     */
    args.setThis(argsobj->as<NativeObject>().getReservedSlot(JSSLOT_DEBUGARGUMENTS_FRAME));
    THIS_FRAME(cx, argc, vp, "get argument", ca2, thisobj, frame);

    /*
     * Since getters can be extracted and applied to other objects,
     * there is no guarantee this object has an ith argument.
     */
    MOZ_ASSERT(i >= 0);
    RootedValue arg(cx);
    RootedScript script(cx);
    if (unsigned(i) < frame.numActualArgs()) {
        script = frame.script();
        {
            AutoCompartment ac(cx, script->compartment());
            if (!script->ensureHasAnalyzedArgsUsage(cx))
                return false;
        }
        if (unsigned(i) < frame.numFormalArgs() && script->formalIsAliased(i)) {
            for (AliasedFormalIter fi(script); ; fi++) {
                if (fi.frameIndex() == unsigned(i)) {
                    arg = frame.callObj().aliasedVar(fi);
                    break;
                }
            }
        } else if (script->argsObjAliasesFormals() && frame.hasArgsObj()) {
            arg = frame.argsObj().arg(i);
        } else {
            arg = frame.unaliasedActual(i, DONT_CHECK_ALIASING);
        }
    } else {
        arg.setUndefined();
    }

    if (!Debugger::fromChildJSObject(thisobj)->wrapDebuggeeValue(cx, &arg))
        return false;
    args.rval().set(arg);
    return true;
}

static bool
DebuggerFrame_getArguments(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "get arguments", args, thisobj, frame);
    Value argumentsv = thisobj->getReservedSlot(JSSLOT_DEBUGFRAME_ARGUMENTS);
    if (!argumentsv.isUndefined()) {
        MOZ_ASSERT(argumentsv.isObjectOrNull());
        args.rval().set(argumentsv);
        return true;
    }

    RootedNativeObject argsobj(cx);
    if (frame.hasArgs()) {
        /* Create an arguments object. */
        Rooted<GlobalObject*> global(cx, &args.callee().global());
        RootedObject proto(cx, GlobalObject::getOrCreateArrayPrototype(cx, global));
        if (!proto)
            return false;
        argsobj = NewNativeObjectWithGivenProto(cx, &DebuggerArguments_class, proto);
        if (!argsobj)
            return false;
        SetReservedSlot(argsobj, JSSLOT_DEBUGARGUMENTS_FRAME, ObjectValue(*thisobj));

        MOZ_ASSERT(frame.numActualArgs() <= 0x7fffffff);
        unsigned fargc = frame.numActualArgs();
        RootedValue fargcVal(cx, Int32Value(fargc));
        if (!NativeDefineProperty(cx, argsobj, cx->names().length, fargcVal, nullptr, nullptr,
                                  JSPROP_PERMANENT | JSPROP_READONLY))
        {
            return false;
        }

        Rooted<jsid> id(cx);
        for (unsigned i = 0; i < fargc; i++) {
            RootedFunction getobj(cx);
            getobj = NewNativeFunction(cx, DebuggerArguments_getArg, 0, nullptr,
                                       gc::AllocKind::FUNCTION_EXTENDED);
            if (!getobj)
                return false;
            id = INT_TO_JSID(i);
            if (!getobj ||
                !NativeDefineProperty(cx, argsobj, id, UndefinedHandleValue,
                                      JS_DATA_TO_FUNC_PTR(GetterOp, getobj.get()), nullptr,
                                      JSPROP_ENUMERATE | JSPROP_SHARED | JSPROP_GETTER))
            {
                return false;
            }
            getobj->setExtendedSlot(0, Int32Value(i));
        }
    } else {
        argsobj = nullptr;
    }
    args.rval().setObjectOrNull(argsobj);
    thisobj->setReservedSlot(JSSLOT_DEBUGFRAME_ARGUMENTS, args.rval());
    return true;
}

static bool
DebuggerFrame_getScript(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "get script", args, thisobj, frame);
    Debugger* debug = Debugger::fromChildJSObject(thisobj);

    RootedObject scriptObject(cx);
    if (frame.isFunctionFrame() && !frame.isEvalFrame()) {
        RootedFunction callee(cx, frame.callee());
        if (callee->isInterpreted()) {
            RootedScript script(cx, callee->nonLazyScript());
            scriptObject = debug->wrapScript(cx, script);
            if (!scriptObject)
                return false;
        }
    } else {
        /*
         * We got eval, JS_Evaluate*, or JS_ExecuteScript non-function script
         * frames.
         */
        RootedScript script(cx, frame.script());
        scriptObject = debug->wrapScript(cx, script);
        if (!scriptObject)
            return false;
    }
    args.rval().setObjectOrNull(scriptObject);
    return true;
}

static bool
DebuggerFrame_getOffset(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME_ITER(cx, argc, vp, "get offset", args, thisobj, _, iter);
    JSScript* script = iter.script();
    UpdateFrameIterPc(iter);
    jsbytecode* pc = iter.pc();
    size_t offset = script->pcToOffset(pc);
    args.rval().setNumber(double(offset));
    return true;
}

static bool
DebuggerFrame_getLive(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);
    NativeObject* thisobj = CheckThisFrame(cx, args, "get live", false);
    if (!thisobj)
        return false;
    bool hasFrame = !!thisobj->getPrivate();
    args.rval().setBoolean(hasFrame);
    return true;
}

static bool
IsValidHook(const Value& v)
{
    return v.isUndefined() || (v.isObject() && v.toObject().isCallable());
}

static bool
DebuggerFrame_getOnStep(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "get onStep", args, thisobj, frame);
    (void) frame;  // Silence GCC warning
    RootedValue handler(cx, thisobj->getReservedSlot(JSSLOT_DEBUGFRAME_ONSTEP_HANDLER));
    MOZ_ASSERT(IsValidHook(handler));
    args.rval().set(handler);
    return true;
}

static bool
DebuggerFrame_setOnStep(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "set onStep", args, thisobj, frame);
    if (!args.requireAtLeast(cx, "Debugger.Frame.set onStep", 1))
        return false;
    if (!IsValidHook(args[0])) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NOT_CALLABLE_OR_UNDEFINED);
        return false;
    }

    Value prior = thisobj->getReservedSlot(JSSLOT_DEBUGFRAME_ONSTEP_HANDLER);
    if (!args[0].isUndefined() && prior.isUndefined()) {
        // Single stepping toggled off->on.
        AutoCompartment ac(cx, frame.scopeChain());
        // Ensure observability *before* incrementing the step mode
        // count. Calling this function after calling incrementStepModeCount
        // will make it a no-op.
        Debugger* dbg = Debugger::fromChildJSObject(thisobj);
        if (!dbg->ensureExecutionObservabilityOfScript(cx, frame.script()))
            return false;
        if (!frame.script()->incrementStepModeCount(cx))
            return false;
    } else if (args[0].isUndefined() && !prior.isUndefined()) {
        // Single stepping toggled on->off.
        frame.script()->decrementStepModeCount(cx->runtime()->defaultFreeOp());
    }

    /* Now that the step mode switch has succeeded, we can install the handler. */
    thisobj->setReservedSlot(JSSLOT_DEBUGFRAME_ONSTEP_HANDLER, args[0]);
    args.rval().setUndefined();
    return true;
}

static bool
DebuggerFrame_getOnPop(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "get onPop", args, thisobj, frame);
    (void) frame;  // Silence GCC warning
    RootedValue handler(cx, thisobj->getReservedSlot(JSSLOT_DEBUGFRAME_ONPOP_HANDLER));
    MOZ_ASSERT(IsValidHook(handler));
    args.rval().set(handler);
    return true;
}

static bool
DebuggerFrame_setOnPop(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME(cx, argc, vp, "set onPop", args, thisobj, frame);
    if (!args.requireAtLeast(cx, "Debugger.Frame.set onPop", 1))
        return false;
    (void) frame;  // Silence GCC warning
    if (!IsValidHook(args[0])) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NOT_CALLABLE_OR_UNDEFINED);
        return false;
    }

    thisobj->setReservedSlot(JSSLOT_DEBUGFRAME_ONPOP_HANDLER, args[0]);
    args.rval().setUndefined();
    return true;
}

/*
 * Evaluate |chars[0..length-1]| in the environment |env|, treating that
 * source as appearing starting at |lineno| in |filename|. Store the return
 * value in |*rval|. Use |thisv| as the 'this' value.
 *
 * If |frame| is non-nullptr, evaluate as for a direct eval in that frame; |env|
 * must be either |frame|'s DebugScopeObject, or some extension of that
 * environment; either way, |frame|'s scope is where newly declared variables
 * go. In this case, |frame| must have a computed 'this' value, equal to |thisv|.
 */
static bool
EvaluateInEnv(JSContext* cx, Handle<Env*> env, HandleValue thisv, AbstractFramePtr frame,
              jsbytecode* pc, mozilla::Range<const char16_t> chars, const char* filename,
              unsigned lineno, MutableHandleValue rval)
{
    assertSameCompartment(cx, env, frame);
    MOZ_ASSERT_IF(frame, thisv.get() == frame.thisValue());
    MOZ_ASSERT_IF(frame, pc);

    /*
     * NB: This function breaks the assumption that the compiler can see all
     * calls and properly compute a static level. In practice, any non-zero
     * static level will suffice.
     *
     * Pass in a StaticEvalObject *not* linked to env for evalStaticScope, as
     * ScopeIter should stop at any non-ScopeObject or non-syntactic With
     * boundaries, and we are putting a DebugScopeProxy or non-syntactic With on
     * the scope chain.
     */
    Rooted<ScopeObject*> enclosingStaticScope(cx);
    if (!env->is<GlobalObject>())
        enclosingStaticScope = StaticNonSyntacticScopeObjects::create(cx, nullptr);

    // Do not consider executeInGlobal{WithBindings} as an eval, but instead
    // as executing a series of statements at the global level. This is to
    // circumvent the fresh lexical scope that all eval have, so that the
    // users of executeInGlobal, like the web console, may add new bindings to
    // the global scope.
    Rooted<ScopeObject*> staticScope(cx);
    if (frame) {
        staticScope = StaticEvalObject::create(cx, enclosingStaticScope);
        if (!staticScope)
            return false;
    } else {
        staticScope = enclosingStaticScope;
    }

    CompileOptions options(cx);
    options.setIsRunOnce(true)
           .setForEval(true)
           .setNoScriptRval(false)
           .setFileAndLine(filename, lineno)
           .setCanLazilyParse(false)
           .setIntroductionType("debugger eval")
           .maybeMakeStrictMode(frame ? frame.script()->strict() : false);
    RootedScript callerScript(cx, frame ? frame.script() : nullptr);
    SourceBufferHolder srcBuf(chars.start().get(), chars.length(), SourceBufferHolder::NoOwnership);
    RootedScript script(cx, frontend::CompileScript(cx, &cx->tempLifoAlloc(), env, staticScope,
                                                    callerScript, options, srcBuf,
                                                    /* source = */ nullptr));
    if (!script)
        return false;

    // Again, executeInGlobal is not considered eval.
    if (frame) {
        if (script->strict())
            staticScope->as<StaticEvalObject>().setStrict();
        script->setActiveEval();
    }

    ExecuteType type = !frame ? EXECUTE_GLOBAL : EXECUTE_DEBUG;
    return ExecuteKernel(cx, script, *env, thisv, NullValue(), type, frame, rval.address());
}

enum EvalBindings { EvalHasExtraBindings = true, EvalWithDefaultBindings = false };

static bool
DebuggerGenericEval(JSContext* cx, const char* fullMethodName, const Value& code,
                    EvalBindings evalWithBindings, HandleValue bindings, HandleValue options,
                    MutableHandleValue vp, Debugger* dbg, HandleObject scope,
                    ScriptFrameIter* iter)
{
    /* Either we're specifying the frame, or a global. */
    MOZ_ASSERT_IF(iter, !scope);
    MOZ_ASSERT_IF(!iter, scope && scope->is<GlobalObject>());

    if (iter && iter->script()->isDerivedClassConstructor()) {
        MOZ_ASSERT(iter->isFunctionFrame() && iter->calleeTemplate()->isClassConstructor());
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DISABLED_DERIVED_CLASS,
                             "debugger eval");
        return false;
    }

    /* Check the first argument, the eval code string. */
    if (!code.isString()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NOT_EXPECTED_TYPE,
                             fullMethodName, "string", InformalValueTypeName(code));
        return false;
    }
    RootedLinearString linear(cx, code.toString()->ensureLinear(cx));
    if (!linear)
        return false;

    /*
     * Gather keys and values of bindings, if any. This must be done in the
     * debugger compartment, since that is where any exceptions must be
     * thrown.
     */
    AutoIdVector keys(cx);
    AutoValueVector values(cx);
    if (evalWithBindings) {
        RootedObject bindingsobj(cx, NonNullObject(cx, bindings));
        if (!bindingsobj ||
            !GetPropertyKeys(cx, bindingsobj, JSITER_OWNONLY, &keys) ||
            !values.growBy(keys.length()))
        {
            return false;
        }
        for (size_t i = 0; i < keys.length(); i++) {
            MutableHandleValue valp = values[i];
            if (!GetProperty(cx, bindingsobj, bindingsobj, keys[i], valp) ||
                !dbg->unwrapDebuggeeValue(cx, valp))
            {
                return false;
            }
        }
    }

    /* Set options from object if provided. */
    JSAutoByteString url_bytes;
    char* url = nullptr;
    unsigned lineNumber = 1;

    if (options.isObject()) {
        RootedObject opts(cx, &options.toObject());
        RootedValue v(cx);

        if (!JS_GetProperty(cx, opts, "url", &v))
            return false;
        if (!v.isUndefined()) {
            RootedString url_str(cx, ToString<CanGC>(cx, v));
            if (!url_str)
                return false;
            url = url_bytes.encodeLatin1(cx, url_str);
            if (!url)
                return false;
        }

        if (!JS_GetProperty(cx, opts, "lineNumber", &v))
            return false;
        if (!v.isUndefined()) {
            uint32_t lineno;
            if (!ToUint32(cx, v, &lineno))
                return false;
            lineNumber = lineno;
        }
    }

    Maybe<AutoCompartment> ac;
    if (iter)
        ac.emplace(cx, iter->scopeChain(cx));
    else
        ac.emplace(cx, scope);

    RootedValue thisv(cx);
    Rooted<Env*> env(cx);
    if (iter) {
        /* ExecuteInEnv requires 'fp' to have a computed 'this" value. */
        if (!iter->computeThis(cx))
            return false;
        thisv = iter->computedThisValue();
        env = GetDebugScopeForFrame(cx, iter->abstractFramePtr(), iter->pc());
        if (!env)
            return false;
    } else {
        /*
         * Use the global as 'this'. If the global is an inner object, it
         * should have a thisObject hook that returns the appropriate outer
         * object.
         */
        JSObject* thisObj = GetThisObject(cx, scope);
        if (!thisObj)
            return false;
        thisv = ObjectValue(*thisObj);
        env = scope;
    }

    /* If evalWithBindings, create the inner environment. */
    if (evalWithBindings) {
        RootedPlainObject nenv(cx, NewObjectWithGivenProto<PlainObject>(cx, nullptr));
        if (!nenv)
            return false;
        RootedId id(cx);
        for (size_t i = 0; i < keys.length(); i++) {
            id = keys[i];
            MutableHandleValue val = values[i];
            if (!cx->compartment()->wrap(cx, val) ||
                !NativeDefineProperty(cx, nenv, id, val, nullptr, nullptr, 0))
            {
                return false;
            }
        }

        AutoObjectVector scopeChain(cx);
        if (!scopeChain.append(nenv))
            return false;

        RootedObject dynamicScope(cx);
        if (!CreateScopeObjectsForScopeChain(cx, scopeChain, env, &dynamicScope))
            return false;

        env = dynamicScope;
    }

    /* Run the code and produce the completion value. */
    RootedValue rval(cx);
    AbstractFramePtr frame = iter ? iter->abstractFramePtr() : NullFramePtr();
    jsbytecode* pc = iter ? iter->pc() : nullptr;
    AutoStableStringChars stableChars(cx);
    if (!stableChars.initTwoByte(cx, linear))
        return false;

    mozilla::Range<const char16_t> chars = stableChars.twoByteRange();
    bool ok = EvaluateInEnv(cx, env, thisv, frame, pc, chars, url ? url : "debugger eval code",
                            lineNumber, &rval);
    return dbg->receiveCompletionValue(ac, ok, rval, vp);
}

static bool
DebuggerFrame_eval(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME_ITER(cx, argc, vp, "eval", args, thisobj, _, iter);
    if (!args.requireAtLeast(cx, "Debugger.Frame.prototype.eval", 1))
        return false;
    Debugger* dbg = Debugger::fromChildJSObject(thisobj);
    UpdateFrameIterPc(iter);
    return DebuggerGenericEval(cx, "Debugger.Frame.prototype.eval",
                               args[0], EvalWithDefaultBindings, JS::UndefinedHandleValue,
                               args.get(1), args.rval(), dbg, nullptr, &iter);
}

static bool
DebuggerFrame_evalWithBindings(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_FRAME_ITER(cx, argc, vp, "evalWithBindings", args, thisobj, _, iter);
    if (!args.requireAtLeast(cx, "Debugger.Frame.prototype.evalWithBindings", 2))
        return false;
    Debugger* dbg = Debugger::fromChildJSObject(thisobj);
    UpdateFrameIterPc(iter);
    return DebuggerGenericEval(cx, "Debugger.Frame.prototype.evalWithBindings",
                               args[0], EvalHasExtraBindings, args[1], args.get(2),
                               args.rval(), dbg, nullptr, &iter);
}

static bool
DebuggerFrame_construct(JSContext* cx, unsigned argc, Value* vp)
{
    JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NO_CONSTRUCTOR,
                         "Debugger.Frame");
    return false;
}

static const JSPropertySpec DebuggerFrame_properties[] = {
    JS_PSG("arguments", DebuggerFrame_getArguments, 0),
    JS_PSG("callee", DebuggerFrame_getCallee, 0),
    JS_PSG("constructing", DebuggerFrame_getConstructing, 0),
    JS_PSG("environment", DebuggerFrame_getEnvironment, 0),
    JS_PSG("generator", DebuggerFrame_getGenerator, 0),
    JS_PSG("live", DebuggerFrame_getLive, 0),
    JS_PSG("offset", DebuggerFrame_getOffset, 0),
    JS_PSG("older", DebuggerFrame_getOlder, 0),
    JS_PSG("script", DebuggerFrame_getScript, 0),
    JS_PSG("this", DebuggerFrame_getThis, 0),
    JS_PSG("type", DebuggerFrame_getType, 0),
    JS_PSG("implementation", DebuggerFrame_getImplementation, 0),
    JS_PSGS("onStep", DebuggerFrame_getOnStep, DebuggerFrame_setOnStep, 0),
    JS_PSGS("onPop", DebuggerFrame_getOnPop, DebuggerFrame_setOnPop, 0),
    JS_PS_END
};

static const JSFunctionSpec DebuggerFrame_methods[] = {
    JS_FN("eval", DebuggerFrame_eval, 1, 0),
    JS_FN("evalWithBindings", DebuggerFrame_evalWithBindings, 1, 0),
    JS_FS_END
};


/*** Debugger.Object *****************************************************************************/

void
DebuggerObject_trace(JSTracer* trc, JSObject* obj)
{
    /*
     * There is a barrier on private pointers, so the Unbarriered marking
     * is okay.
     */
    if (JSObject* referent = (JSObject*) obj->as<NativeObject>().getPrivate()) {
        TraceManuallyBarrieredCrossCompartmentEdge(trc, obj, &referent,
                                                   "Debugger.Object referent");
        obj->as<NativeObject>().setPrivateUnbarriered(referent);
    }
}

const Class DebuggerObject_class = {
    "Object",
    JSCLASS_HAS_PRIVATE |
    JSCLASS_HAS_RESERVED_SLOTS(JSSLOT_DEBUGOBJECT_COUNT),
    nullptr, nullptr, nullptr, nullptr, nullptr,
    nullptr, nullptr, nullptr, nullptr,
    nullptr,              /* call        */
    nullptr,              /* hasInstance */
    nullptr,              /* construct   */
    DebuggerObject_trace
};

static NativeObject*
DebuggerObject_checkThis(JSContext* cx, const CallArgs& args, const char* fnname)
{
    JSObject* thisobj = NonNullObject(cx, args.thisv());
    if (!thisobj)
        return nullptr;
    if (thisobj->getClass() != &DebuggerObject_class) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger.Object", fnname, thisobj->getClass()->name);
        return nullptr;
    }

    /*
     * Forbid Debugger.Object.prototype, which is of class DebuggerObject_class
     * but isn't a real working Debugger.Object. The prototype object is
     * distinguished by having no referent.
     */
    NativeObject* nthisobj = &thisobj->as<NativeObject>();
    if (!nthisobj->getPrivate()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger.Object", fnname, "prototype object");
        return nullptr;
    }
    return nthisobj;
}

#define THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, fnname, args, obj)            \
    CallArgs args = CallArgsFromVp(argc, vp);                                 \
    RootedObject obj(cx, DebuggerObject_checkThis(cx, args, fnname));         \
    if (!obj)                                                                 \
        return false;                                                         \
    obj = (JSObject*) obj->as<NativeObject>().getPrivate();                   \
    MOZ_ASSERT(obj)

#define THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, fnname, args, dbg, obj) \
   CallArgs args = CallArgsFromVp(argc, vp);                                  \
   RootedObject obj(cx, DebuggerObject_checkThis(cx, args, fnname));          \
   if (!obj)                                                                  \
       return false;                                                          \
   Debugger* dbg = Debugger::fromChildJSObject(obj);                          \
   obj = (JSObject*) obj->as<NativeObject>().getPrivate();                    \
   MOZ_ASSERT(obj)

static bool
DebuggerObject_construct(JSContext* cx, unsigned argc, Value* vp)
{
    JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NO_CONSTRUCTOR,
                         "Debugger.Object");
    return false;
}

static bool
DebuggerObject_getProto(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get proto", args, dbg, refobj);
    RootedObject proto(cx);
    {
        AutoCompartment ac(cx, refobj);
        if (!GetPrototype(cx, refobj, &proto))
            return false;
    }
    RootedValue protov(cx, ObjectOrNullValue(proto));
    if (!dbg->wrapDebuggeeValue(cx, &protov))
        return false;
    args.rval().set(protov);
    return true;
}

static bool
DebuggerObject_getClass(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, "get class", args, refobj);
    const char* className;
    {
        AutoCompartment ac(cx, refobj);
        className = GetObjectClassName(cx, refobj);
    }
    JSAtom* str = Atomize(cx, className, strlen(className));
    if (!str)
        return false;
    args.rval().setString(str);
    return true;
}

static bool
DebuggerObject_getCallable(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, "get callable", args, refobj);
    args.rval().setBoolean(refobj->isCallable());
    return true;
}

static bool
DebuggerObject_getName(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get name", args, dbg, obj);
    if (!obj->is<JSFunction>()) {
        args.rval().setUndefined();
        return true;
    }

    JSString* name = obj->as<JSFunction>().atom();
    if (!name) {
        args.rval().setUndefined();
        return true;
    }

    RootedValue namev(cx, StringValue(name));
    if (!dbg->wrapDebuggeeValue(cx, &namev))
        return false;
    args.rval().set(namev);
    return true;
}

static bool
DebuggerObject_getDisplayName(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get display name", args, dbg, obj);
    if (!obj->is<JSFunction>()) {
        args.rval().setUndefined();
        return true;
    }

    JSString* name = obj->as<JSFunction>().displayAtom();
    if (!name) {
        args.rval().setUndefined();
        return true;
    }

    RootedValue namev(cx, StringValue(name));
    if (!dbg->wrapDebuggeeValue(cx, &namev))
        return false;
    args.rval().set(namev);
    return true;
}

static bool
DebuggerObject_getParameterNames(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get parameterNames", args, dbg, obj);
    if (!obj->is<JSFunction>()) {
        args.rval().setUndefined();
        return true;
    }

    RootedFunction fun(cx, &obj->as<JSFunction>());

    /* Only hand out parameter info for debuggee functions. */
    if (!dbg->observesGlobal(&fun->global())) {
        args.rval().setUndefined();
        return true;
    }

    RootedArrayObject result(cx, NewDenseFullyAllocatedArray(cx, fun->nargs()));
    if (!result)
        return false;
    result->ensureDenseInitializedLength(cx, 0, fun->nargs());

    if (fun->isInterpreted()) {
        RootedScript script(cx, GetOrCreateFunctionScript(cx, fun));
        if (!script)
            return false;

        MOZ_ASSERT(fun->nargs() == script->bindings.numArgs());

        if (fun->nargs() > 0) {
            BindingIter bi(script);
            for (size_t i = 0; i < fun->nargs(); i++, bi++) {
                MOZ_ASSERT(bi.argIndex() == i);
                Value v;
                if (bi->name()->length() == 0)
                    v = UndefinedValue();
                else
                    v = StringValue(bi->name());
                result->setDenseElement(i, v);
            }
        }
    } else {
        for (size_t i = 0; i < fun->nargs(); i++)
            result->setDenseElement(i, UndefinedValue());
    }

    args.rval().setObject(*result);
    return true;
}

static bool
DebuggerObject_getScript(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get script", args, dbg, obj);

    if (!obj->is<JSFunction>()) {
        args.rval().setUndefined();
        return true;
    }

    RootedFunction fun(cx, &obj->as<JSFunction>());
    if (fun->isBuiltin()) {
        args.rval().setUndefined();
        return true;
    }

    RootedScript script(cx, GetOrCreateFunctionScript(cx, fun));
    if (!script)
        return false;

    /* Only hand out debuggee scripts. */
    if (!dbg->observesScript(script)) {
        args.rval().setNull();
        return true;
    }

    RootedObject scriptObject(cx, dbg->wrapScript(cx, script));
    if (!scriptObject)
        return false;

    args.rval().setObject(*scriptObject);
    return true;
}

static bool
DebuggerObject_getEnvironment(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get environment", args, dbg, obj);

    /* Don't bother switching compartments just to check obj's type and get its env. */
    if (!obj->is<JSFunction>() || !obj->as<JSFunction>().isInterpreted()) {
        args.rval().setUndefined();
        return true;
    }

    /* Only hand out environments of debuggee functions. */
    if (!dbg->observesGlobal(&obj->global())) {
        args.rval().setNull();
        return true;
    }

    Rooted<Env*> env(cx);
    {
        AutoCompartment ac(cx, obj);
        RootedFunction fun(cx, &obj->as<JSFunction>());
        env = GetDebugScopeForFunction(cx, fun);
        if (!env)
            return false;
    }

    return dbg->wrapEnvironment(cx, env, args.rval());
}

static bool
DebuggerObject_getIsArrowFunction(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, "get isArrowFunction", args, refobj);

    args.rval().setBoolean(refobj->is<JSFunction>()
                           && refobj->as<JSFunction>().isArrow());
    return true;
}

static bool
DebuggerObject_getIsBoundFunction(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, "get isBoundFunction", args, refobj);

    args.rval().setBoolean(refobj->isBoundFunction());
    return true;
}

static bool
DebuggerObject_getBoundTargetFunction(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get boundFunctionTarget", args, dbg, refobj);

    if (!refobj->isBoundFunction()) {
        args.rval().setUndefined();
        return true;
    }

    args.rval().setObject(*refobj->as<JSFunction>().getBoundFunctionTarget());
    return dbg->wrapDebuggeeValue(cx, args.rval());
}

static bool
DebuggerObject_getBoundThis(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get boundThis", args, dbg, refobj);

    if (!refobj->isBoundFunction()) {
        args.rval().setUndefined();
        return true;
    }
    args.rval().set(refobj->as<JSFunction>().getBoundFunctionThis());
    return dbg->wrapDebuggeeValue(cx, args.rval());
}

static bool
DebuggerObject_getBoundArguments(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get boundArguments", args, dbg, refobj);

    if (!refobj->isBoundFunction()) {
        args.rval().setUndefined();
        return true;
    }

    Rooted<JSFunction*> fun(cx, &refobj->as<JSFunction>());
    size_t length = fun->getBoundFunctionArgumentCount();
    AutoValueVector boundArgs(cx);
    if (!boundArgs.resize(length))
        return false;
    for (size_t i = 0; i < length; i++) {
        boundArgs[i].set(fun->getBoundFunctionArgument(i));
        if (!dbg->wrapDebuggeeValue(cx, boundArgs[i]))
            return false;
    }

    JSObject* aobj = NewDenseCopiedArray(cx, boundArgs.length(), boundArgs.begin());
    if (!aobj)
        return false;
    args.rval().setObject(*aobj);
    return true;
}

static bool
DebuggerObject_getGlobal(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "get global", args, dbg, obj);

    RootedValue v(cx, ObjectValue(obj->global()));
    if (!dbg->wrapDebuggeeValue(cx, &v))
        return false;
    args.rval().set(v);
    return true;
}

static bool
null(CallArgs& args)
{
    args.rval().setNull();
    return true;
}

/* static */ SavedFrame*
Debugger::getObjectAllocationSite(JSObject& obj)
{
    JSObject* metadata = GetObjectMetadata(&obj);
    if (!metadata)
        return nullptr;

    MOZ_ASSERT(!metadata->is<WrapperObject>());
    return SavedFrame::isSavedFrameAndNotProto(*metadata)
        ? &metadata->as<SavedFrame>()
        : nullptr;
}

static bool
DebuggerObject_getAllocationSite(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, "get allocationSite", args, obj);

    RootedObject allocSite(cx, Debugger::getObjectAllocationSite(*obj));
    if (!allocSite)
        return null(args);
    if (!cx->compartment()->wrap(cx, &allocSite))
        return false;
    args.rval().setObject(*allocSite);
    return true;
}

static bool
DebuggerObject_getOwnPropertyDescriptor(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "getOwnPropertyDescriptor", args, dbg, obj);

    RootedId id(cx);
    if (!ValueToId<CanGC>(cx, args.get(0), &id))
        return false;

    /* Bug: This can cause the debuggee to run! */
    Rooted<PropertyDescriptor> desc(cx);
    {
        Maybe<AutoCompartment> ac;
        ac.emplace(cx, obj);

        ErrorCopier ec(ac);
        if (!GetOwnPropertyDescriptor(cx, obj, id, &desc))
            return false;
    }

    if (desc.object()) {
        /* Rewrap the debuggee values in desc for the debugger. */
        if (!dbg->wrapDebuggeeValue(cx, desc.value()))
            return false;

        if (desc.hasGetterObject()) {
            RootedValue get(cx, ObjectOrNullValue(desc.getterObject()));
            if (!dbg->wrapDebuggeeValue(cx, &get))
                return false;
            desc.setGetterObject(get.toObjectOrNull());
        }
        if (desc.hasSetterObject()) {
            RootedValue set(cx, ObjectOrNullValue(desc.setterObject()));
            if (!dbg->wrapDebuggeeValue(cx, &set))
                return false;
            desc.setSetterObject(set.toObjectOrNull());
        }
    }

    return FromPropertyDescriptor(cx, desc, args.rval());
}


static bool
getOwnPropertyKeys(JSContext* cx, unsigned argc, unsigned flags, Value* vp)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, "getOwnPropertyKeys", args, obj);
    AutoIdVector keys(cx);
    {
        Maybe<AutoCompartment> ac;
        ac.emplace(cx, obj);
        ErrorCopier ec(ac);
        if (!GetPropertyKeys(cx, obj, flags, &keys))
            return false;
    }

    AutoValueVector vals(cx);
    if (!vals.resize(keys.length()))
        return false;

    for (size_t i = 0, len = keys.length(); i < len; i++) {
         jsid id = keys[i];
         if (JSID_IS_INT(id)) {
             JSString* str = Int32ToString<CanGC>(cx, JSID_TO_INT(id));
             if (!str)
                 return false;
             vals[i].setString(str);
         } else if (JSID_IS_ATOM(id)) {
             vals[i].setString(JSID_TO_STRING(id));
         } else if (JSID_IS_SYMBOL(id)) {
             vals[i].setSymbol(JSID_TO_SYMBOL(id));
         } else {
             MOZ_ASSERT_UNREACHABLE("GetPropertyKeys must return only string, int, and Symbol jsids");
         }
    }

    JSObject* aobj = NewDenseCopiedArray(cx, vals.length(), vals.begin());
    if (!aobj)
        return false;
    args.rval().setObject(*aobj);
    return true;
}

static bool
DebuggerObject_getOwnPropertyNames(JSContext* cx, unsigned argc, Value* vp) {
    return getOwnPropertyKeys(cx, argc, JSITER_OWNONLY | JSITER_HIDDEN, vp);
}

static bool
DebuggerObject_getOwnPropertySymbols(JSContext* cx, unsigned argc, Value* vp) {
    return getOwnPropertyKeys(cx, argc,
                              JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS | JSITER_SYMBOLSONLY,
                              vp);
}

static bool
DebuggerObject_defineProperty(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "defineProperty", args, dbg, obj);
    if (!args.requireAtLeast(cx, "Debugger.Object.defineProperty", 2))
        return false;

    RootedId id(cx);
    if (!ValueToId<CanGC>(cx, args[0], &id))
        return false;

    Rooted<PropertyDescriptor> desc(cx);
    if (!ToPropertyDescriptor(cx, args[1], false, &desc))
        return false;

    if (!dbg->unwrapPropertyDescriptor(cx, obj, &desc))
        return false;
    if (!CheckPropertyDescriptorAccessors(cx, desc))
        return false;

    {
        Maybe<AutoCompartment> ac;
        ac.emplace(cx, obj);
        if (!cx->compartment()->wrap(cx, &desc))
            return false;

        ErrorCopier ec(ac);
        if (!DefineProperty(cx, obj, id, desc))
            return false;
    }

    args.rval().setUndefined();
    return true;
}

static bool
DebuggerObject_defineProperties(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "defineProperties", args, dbg, obj);
    if (!args.requireAtLeast(cx, "Debugger.Object.defineProperties", 1))
        return false;

    RootedValue arg(cx, args[0]);
    RootedObject props(cx, ToObject(cx, arg));
    if (!props)
        return false;

    AutoIdVector ids(cx);
    Rooted<PropertyDescriptorVector> descs(cx, PropertyDescriptorVector(cx));
    if (!ReadPropertyDescriptors(cx, props, false, &ids, &descs))
        return false;
    size_t n = ids.length();

    for (size_t i = 0; i < n; i++) {
        if (!dbg->unwrapPropertyDescriptor(cx, obj, descs[i]))
            return false;
        if (!CheckPropertyDescriptorAccessors(cx, descs[i]))
            return false;
    }

    {
        Maybe<AutoCompartment> ac;
        ac.emplace(cx, obj);
        for (size_t i = 0; i < n; i++) {
            if (!cx->compartment()->wrap(cx, descs[i]))
                return false;
        }

        ErrorCopier ec(ac);
        for (size_t i = 0; i < n; i++) {
            if (!DefineProperty(cx, obj, ids[i], descs[i]))
                return false;
        }
    }

    args.rval().setUndefined();
    return true;
}

/*
 * This does a non-strict delete, as a matter of API design. The case where the
 * property is non-configurable isn't necessarily exceptional here.
 */
static bool
DebuggerObject_deleteProperty(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, "deleteProperty", args, obj);
    RootedId id(cx);
    if (!ValueToId<CanGC>(cx, args.get(0), &id))
        return false;

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, obj);
    ErrorCopier ec(ac);

    ObjectOpResult result;
    if (!DeleteProperty(cx, obj, id, result))
        return false;
    args.rval().setBoolean(result.ok());
    return true;
}

enum SealHelperOp { OpSeal, OpFreeze, OpPreventExtensions };

static bool
DebuggerObject_sealHelper(JSContext* cx, unsigned argc, Value* vp, SealHelperOp op, const char* name)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, name, args, obj);

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, obj);
    ErrorCopier ec(ac);
    if (op == OpSeal) {
        if (!SetIntegrityLevel(cx, obj, IntegrityLevel::Sealed))
            return false;
    } else if (op == OpFreeze) {
        if (!SetIntegrityLevel(cx, obj, IntegrityLevel::Frozen))
            return false;
    } else {
        MOZ_ASSERT(op == OpPreventExtensions);
        if (!PreventExtensions(cx, obj))
            return false;
    }
    args.rval().setUndefined();
    return true;
}

static bool
DebuggerObject_seal(JSContext* cx, unsigned argc, Value* vp)
{
    return DebuggerObject_sealHelper(cx, argc, vp, OpSeal, "seal");
}

static bool
DebuggerObject_freeze(JSContext* cx, unsigned argc, Value* vp)
{
    return DebuggerObject_sealHelper(cx, argc, vp, OpFreeze, "freeze");
}

static bool
DebuggerObject_preventExtensions(JSContext* cx, unsigned argc, Value* vp)
{
    return DebuggerObject_sealHelper(cx, argc, vp, OpPreventExtensions, "preventExtensions");
}

static bool
DebuggerObject_isSealedHelper(JSContext* cx, unsigned argc, Value* vp, SealHelperOp op,
                              const char* name)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, name, args, obj);

    Maybe<AutoCompartment> ac;
    ac.emplace(cx, obj);
    ErrorCopier ec(ac);
    bool r;
    if (op == OpSeal) {
        if (!TestIntegrityLevel(cx, obj, IntegrityLevel::Sealed, &r))
            return false;
    } else if (op == OpFreeze) {
        if (!TestIntegrityLevel(cx, obj, IntegrityLevel::Frozen, &r))
            return false;
    } else {
        if (!IsExtensible(cx, obj, &r))
            return false;
    }
    args.rval().setBoolean(r);
    return true;
}

static bool
DebuggerObject_isSealed(JSContext* cx, unsigned argc, Value* vp)
{
    return DebuggerObject_isSealedHelper(cx, argc, vp, OpSeal, "isSealed");
}

static bool
DebuggerObject_isFrozen(JSContext* cx, unsigned argc, Value* vp)
{
    return DebuggerObject_isSealedHelper(cx, argc, vp, OpFreeze, "isFrozen");
}

static bool
DebuggerObject_isExtensible(JSContext* cx, unsigned argc, Value* vp)
{
    return DebuggerObject_isSealedHelper(cx, argc, vp, OpPreventExtensions, "isExtensible");
}

enum ApplyOrCallMode { ApplyMode, CallMode };

static bool
ApplyOrCall(JSContext* cx, unsigned argc, Value* vp, ApplyOrCallMode mode)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "apply", args, dbg, obj);

    /*
     * Any JS exceptions thrown must be in the debugger compartment, so do
     * sanity checks and fallible conversions before entering the debuggee.
     */
    RootedValue calleev(cx, ObjectValue(*obj));
    if (!obj->isCallable()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger.Object", "apply", obj->getClass()->name);
        return false;
    }

    /*
     * Unwrap Debugger.Objects. This happens in the debugger's compartment since
     * that is where any exceptions must be reported.
     */
    RootedValue thisv(cx, args.get(0));
    if (!dbg->unwrapDebuggeeValue(cx, &thisv))
        return false;
    unsigned callArgc = 0;
    Value* callArgv = nullptr;
    AutoValueVector argv(cx);
    if (mode == ApplyMode) {
        if (args.length() >= 2 && !args[1].isNullOrUndefined()) {
            if (!args[1].isObject()) {
                JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_BAD_APPLY_ARGS,
                                     js_apply_str);
                return false;
            }
            RootedObject argsobj(cx, &args[1].toObject());
            if (!GetLengthProperty(cx, argsobj, &callArgc))
                return false;
            callArgc = unsigned(Min(callArgc, ARGS_LENGTH_MAX));
            if (!argv.growBy(callArgc) || !GetElements(cx, argsobj, callArgc, argv.begin()))
                return false;
            callArgv = argv.begin();
        }
    } else {
        callArgc = args.length() > 0 ? unsigned(Min(args.length() - 1, ARGS_LENGTH_MAX)) : 0;
        callArgv = args.array() + 1;
    }

    AutoArrayRooter callArgvRooter(cx, callArgc, callArgv);
    for (unsigned i = 0; i < callArgc; i++) {
        if (!dbg->unwrapDebuggeeValue(cx, callArgvRooter.handleAt(i)))
            return false;
    }

    /*
     * Enter the debuggee compartment and rewrap all input value for that compartment.
     * (Rewrapping always takes place in the destination compartment.)
     */
    Maybe<AutoCompartment> ac;
    ac.emplace(cx, obj);
    if (!cx->compartment()->wrap(cx, &calleev) || !cx->compartment()->wrap(cx, &thisv))
        return false;

    RootedValue arg(cx);
    for (unsigned i = 0; i < callArgc; i++) {
        if (!cx->compartment()->wrap(cx, callArgvRooter.handleAt(i)))
             return false;
    }

    /*
     * Call the function. Use receiveCompletionValue to return to the debugger
     * compartment and populate args.rval().
     */
    RootedValue rval(cx);
    bool ok = Invoke(cx, thisv, calleev, callArgc, callArgv, &rval);
    return dbg->receiveCompletionValue(ac, ok, rval, args.rval());
}

static bool
DebuggerObject_apply(JSContext* cx, unsigned argc, Value* vp)
{
    return ApplyOrCall(cx, argc, vp, ApplyMode);
}

static bool
DebuggerObject_call(JSContext* cx, unsigned argc, Value* vp)
{
    return ApplyOrCall(cx, argc, vp, CallMode);
}

static bool
DebuggerObject_makeDebuggeeValue(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "makeDebuggeeValue", args, dbg, referent);
    if (!args.requireAtLeast(cx, "Debugger.Object.prototype.makeDebuggeeValue", 1))
        return false;

    RootedValue arg0(cx, args[0]);

    /* Non-objects are already debuggee values. */
    if (arg0.isObject()) {
        // Enter this Debugger.Object's referent's compartment, and wrap the
        // argument as appropriate for references from there.
        {
            AutoCompartment ac(cx, referent);
            if (!cx->compartment()->wrap(cx, &arg0))
                return false;
        }

        // Back in the debugger's compartment, produce a new Debugger.Object
        // instance referring to the wrapped argument.
        if (!dbg->wrapDebuggeeValue(cx, &arg0))
            return false;
    }

    args.rval().set(arg0);
    return true;
}

static bool
RequireGlobalObject(JSContext* cx, HandleValue dbgobj, HandleObject referent)
{
    RootedObject obj(cx, referent);

    if (!obj->is<GlobalObject>()) {
        const char* isWrapper = "";
        const char* isWindowProxy = "";

        /* Help the poor programmer by pointing out wrappers around globals... */
        if (obj->is<WrapperObject>()) {
            obj = js::UncheckedUnwrap(obj);
            isWrapper = "a wrapper around ";
        }

        /* ... and WindowProxies around Windows. */
        if (IsOuterObject(obj)) {
            obj = JS_ObjectToInnerObject(cx, obj);
            isWindowProxy = "a WindowProxy referring to ";
        }

        if (obj->is<GlobalObject>()) {
            ReportValueErrorFlags(cx, JSREPORT_ERROR, JSMSG_DEBUG_WRAPPER_IN_WAY,
                                  JSDVG_SEARCH_STACK, dbgobj, nullptr,
                                  isWrapper, isWindowProxy);
        } else {
            ReportValueErrorFlags(cx, JSREPORT_ERROR, JSMSG_DEBUG_BAD_REFERENT,
                                  JSDVG_SEARCH_STACK, dbgobj, nullptr,
                                  "a global object", nullptr);
        }
        return false;
    }

    return true;
}

static bool
DebuggerObject_executeInGlobal(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "executeInGlobal", args, dbg, referent);
    if (!args.requireAtLeast(cx, "Debugger.Object.prototype.executeInGlobal", 1))
        return false;
    if (!RequireGlobalObject(cx, args.thisv(), referent))
        return false;

    return DebuggerGenericEval(cx, "Debugger.Object.prototype.executeInGlobal",
                               args[0], EvalWithDefaultBindings, JS::UndefinedHandleValue,
                               args.get(1), args.rval(), dbg, referent, nullptr);
}

static bool
DebuggerObject_executeInGlobalWithBindings(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "executeInGlobalWithBindings", args, dbg,
                                    referent);
    if (!args.requireAtLeast(cx, "Debugger.Object.prototype.executeInGlobalWithBindings", 2))
        return false;
    if (!RequireGlobalObject(cx, args.thisv(), referent))
        return false;

    return DebuggerGenericEval(cx, "Debugger.Object.prototype.executeInGlobalWithBindings",
                               args[0], EvalHasExtraBindings, args[1], args.get(2),
                               args.rval(), dbg, referent, nullptr);
}

static bool
DebuggerObject_unwrap(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_OWNER_REFERENT(cx, argc, vp, "unwrap", args, dbg, referent);
    JSObject* unwrapped = UnwrapOneChecked(referent);
    if (!unwrapped) {
        args.rval().setNull();
        return true;
    }

    // Don't allow unwrapping to create a D.O whose referent is in an
    // invisible-to-Debugger global. (If our referent is a *wrapper* to such,
    // and the wrapper is in a visible compartment, that's fine.)
    JSCompartment* unwrappedCompartment = unwrapped->compartment();
    if (unwrappedCompartment->options().invisibleToDebugger()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
                             JSMSG_DEBUG_INVISIBLE_COMPARTMENT);
        return false;
    }

    args.rval().setObject(*unwrapped);
    if (!dbg->wrapDebuggeeValue(cx, args.rval()))
        return false;
    return true;
}

static bool
DebuggerObject_unsafeDereference(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGOBJECT_REFERENT(cx, argc, vp, "unsafeDereference", args, referent);
    args.rval().setObject(*referent);
    if (!cx->compartment()->wrap(cx, args.rval()))
        return false;

    // Wrapping should outerize inner objects.
    MOZ_ASSERT(!IsInnerObject(&args.rval().toObject()));

    return true;
}

static const JSPropertySpec DebuggerObject_properties[] = {
    JS_PSG("proto", DebuggerObject_getProto, 0),
    JS_PSG("class", DebuggerObject_getClass, 0),
    JS_PSG("callable", DebuggerObject_getCallable, 0),
    JS_PSG("name", DebuggerObject_getName, 0),
    JS_PSG("displayName", DebuggerObject_getDisplayName, 0),
    JS_PSG("parameterNames", DebuggerObject_getParameterNames, 0),
    JS_PSG("script", DebuggerObject_getScript, 0),
    JS_PSG("environment", DebuggerObject_getEnvironment, 0),
    JS_PSG("isArrowFunction", DebuggerObject_getIsArrowFunction, 0),
    JS_PSG("isBoundFunction", DebuggerObject_getIsBoundFunction, 0),
    JS_PSG("boundTargetFunction", DebuggerObject_getBoundTargetFunction, 0),
    JS_PSG("boundThis", DebuggerObject_getBoundThis, 0),
    JS_PSG("boundArguments", DebuggerObject_getBoundArguments, 0),
    JS_PSG("global", DebuggerObject_getGlobal, 0),
    JS_PSG("allocationSite", DebuggerObject_getAllocationSite, 0),
    JS_PS_END
};

static const JSFunctionSpec DebuggerObject_methods[] = {
    JS_FN("getOwnPropertyDescriptor", DebuggerObject_getOwnPropertyDescriptor, 1, 0),
    JS_FN("getOwnPropertyNames", DebuggerObject_getOwnPropertyNames, 0, 0),
    JS_FN("getOwnPropertySymbols", DebuggerObject_getOwnPropertySymbols, 0, 0),
    JS_FN("defineProperty", DebuggerObject_defineProperty, 2, 0),
    JS_FN("defineProperties", DebuggerObject_defineProperties, 1, 0),
    JS_FN("deleteProperty", DebuggerObject_deleteProperty, 1, 0),
    JS_FN("seal", DebuggerObject_seal, 0, 0),
    JS_FN("freeze", DebuggerObject_freeze, 0, 0),
    JS_FN("preventExtensions", DebuggerObject_preventExtensions, 0, 0),
    JS_FN("isSealed", DebuggerObject_isSealed, 0, 0),
    JS_FN("isFrozen", DebuggerObject_isFrozen, 0, 0),
    JS_FN("isExtensible", DebuggerObject_isExtensible, 0, 0),
    JS_FN("apply", DebuggerObject_apply, 0, 0),
    JS_FN("call", DebuggerObject_call, 0, 0),
    JS_FN("makeDebuggeeValue", DebuggerObject_makeDebuggeeValue, 1, 0),
    JS_FN("executeInGlobal", DebuggerObject_executeInGlobal, 1, 0),
    JS_FN("executeInGlobalWithBindings", DebuggerObject_executeInGlobalWithBindings, 2, 0),
    JS_FN("unwrap", DebuggerObject_unwrap, 0, 0),
    JS_FN("unsafeDereference", DebuggerObject_unsafeDereference, 0, 0),
    JS_FS_END
};


/*** Debugger.Environment ************************************************************************/

void
DebuggerEnv_trace(JSTracer* trc, JSObject* obj)
{
    /*
     * There is a barrier on private pointers, so the Unbarriered marking
     * is okay.
     */
    if (Env* referent = (JSObject*) obj->as<NativeObject>().getPrivate()) {
        TraceManuallyBarrieredCrossCompartmentEdge(trc, obj, &referent,
                                                   "Debugger.Environment referent");
        obj->as<NativeObject>().setPrivateUnbarriered(referent);
    }
}

const Class DebuggerEnv_class = {
    "Environment",
    JSCLASS_HAS_PRIVATE |
    JSCLASS_HAS_RESERVED_SLOTS(JSSLOT_DEBUGENV_COUNT),
    nullptr, nullptr, nullptr, nullptr, nullptr,
    nullptr, nullptr, nullptr, nullptr,
    nullptr,              /* call        */
    nullptr,              /* hasInstance */
    nullptr,              /* construct   */
    DebuggerEnv_trace
};

static NativeObject*
DebuggerEnv_checkThis(JSContext* cx, const CallArgs& args, const char* fnname,
                      bool requireDebuggee = true)
{
    JSObject* thisobj = NonNullObject(cx, args.thisv());
    if (!thisobj)
        return nullptr;
    if (thisobj->getClass() != &DebuggerEnv_class) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger.Environment", fnname, thisobj->getClass()->name);
        return nullptr;
    }

    /*
     * Forbid Debugger.Environment.prototype, which is of class DebuggerEnv_class
     * but isn't a real working Debugger.Environment. The prototype object is
     * distinguished by having no referent.
     */
    NativeObject* nthisobj = &thisobj->as<NativeObject>();
    if (!nthisobj->getPrivate()) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
                             "Debugger.Environment", fnname, "prototype object");
        return nullptr;
    }

    /*
     * Forbid access to Debugger.Environment objects that are not debuggee
     * environments.
     */
    if (requireDebuggee) {
        Rooted<Env*> env(cx, static_cast<Env*>(nthisobj->getPrivate()));
        if (!Debugger::fromChildJSObject(nthisobj)->observesGlobal(&env->global())) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_NOT_DEBUGGEE,
                                 "Debugger.Environment", "environment");
            return nullptr;
        }
    }

    return nthisobj;
}

#define THIS_DEBUGENV(cx, argc, vp, fnname, args, envobj, env)                \
    CallArgs args = CallArgsFromVp(argc, vp);                                 \
    NativeObject* envobj = DebuggerEnv_checkThis(cx, args, fnname);           \
    if (!envobj)                                                              \
        return false;                                                         \
    Rooted<Env*> env(cx, static_cast<Env*>(envobj->getPrivate()));            \
    MOZ_ASSERT(env);                                                          \
    MOZ_ASSERT(!IsSyntacticScope(env));

 #define THIS_DEBUGENV_OWNER(cx, argc, vp, fnname, args, envobj, env, dbg)    \
     THIS_DEBUGENV(cx, argc, vp, fnname, args, envobj, env);                  \
    Debugger* dbg = Debugger::fromChildJSObject(envobj)

static bool
DebuggerEnv_construct(JSContext* cx, unsigned argc, Value* vp)
{
    JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_NO_CONSTRUCTOR,
                         "Debugger.Environment");
    return false;
}

static bool
IsDeclarative(Env* env)
{
    return env->is<DebugScopeObject>() && env->as<DebugScopeObject>().isForDeclarative();
}

static bool
IsWith(Env* env)
{
    return env->is<DebugScopeObject>() &&
           env->as<DebugScopeObject>().scope().is<DynamicWithObject>();
}

static bool
DebuggerEnv_getType(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGENV(cx, argc, vp, "get type", args, envobj, env);

    /* Don't bother switching compartments just to check env's class. */
    const char* s;
    if (IsDeclarative(env))
        s = "declarative";
    else if (IsWith(env))
        s = "with";
    else
        s = "object";

    JSAtom* str = Atomize(cx, s, strlen(s), PinAtom);
    if (!str)
        return false;
    args.rval().setString(str);
    return true;
}

static bool
DebuggerEnv_getParent(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGENV_OWNER(cx, argc, vp, "get parent", args, envobj, env, dbg);

    /* Don't bother switching compartments just to get env's parent. */
    Rooted<Env*> parent(cx, env->enclosingScope());
    return dbg->wrapEnvironment(cx, parent, args.rval());
}

static bool
DebuggerEnv_getObject(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGENV_OWNER(cx, argc, vp, "get type", args, envobj, env, dbg);

    /*
     * Don't bother switching compartments just to check env's class and
     * possibly get its proto.
     */
    if (IsDeclarative(env)) {
        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_NO_SCOPE_OBJECT);
        return false;
    }

    JSObject* obj;
    if (IsWith(env)) {
        obj = &env->as<DebugScopeObject>().scope().as<DynamicWithObject>().object();
    } else {
        obj = env;
        MOZ_ASSERT(!obj->is<DebugScopeObject>());
    }

    args.rval().setObject(*obj);
    if (!dbg->wrapDebuggeeValue(cx, args.rval()))
        return false;
    return true;
}

static bool
DebuggerEnv_getCallee(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGENV_OWNER(cx, argc, vp, "get callee", args, envobj, env, dbg);

    args.rval().setNull();

    if (!env->is<DebugScopeObject>())
        return true;

    JSObject& scope = env->as<DebugScopeObject>().scope();
    if (!scope.is<CallObject>())
        return true;

    CallObject& callobj = scope.as<CallObject>();
    if (callobj.isForEval())
        return true;

    JSFunction& callee = callobj.callee();
    if (IsInternalFunctionObject(callee))
        return true;

    args.rval().setObject(callee);
    if (!dbg->wrapDebuggeeValue(cx, args.rval()))
        return false;
    return true;
}

static bool
DebuggerEnv_getInspectable(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);
    NativeObject* envobj = DebuggerEnv_checkThis(cx, args, "get inspectable", false);
    if (!envobj)
        return false;
    Rooted<Env*> env(cx, static_cast<Env*>(envobj->getPrivate()));
    MOZ_ASSERT(env);
    MOZ_ASSERT(!env->is<ScopeObject>());

    Debugger* dbg = Debugger::fromChildJSObject(envobj);

    args.rval().setBoolean(dbg->observesGlobal(&env->global()));
    return true;
}

static bool
DebuggerEnv_getOptimizedOut(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);
    NativeObject* envobj = DebuggerEnv_checkThis(cx, args, "get optimizedOut", false);
    if (!envobj)
        return false;
    Rooted<Env*> env(cx, static_cast<Env*>(envobj->getPrivate()));
    MOZ_ASSERT(env);
    MOZ_ASSERT(!env->is<ScopeObject>());

    args.rval().setBoolean(env->is<DebugScopeObject>() &&
                           env->as<DebugScopeObject>().isOptimizedOut());
    return true;
}

static bool
DebuggerEnv_names(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGENV(cx, argc, vp, "names", args, envobj, env);

    AutoIdVector keys(cx);
    {
        Maybe<AutoCompartment> ac;
        ac.emplace(cx, env);
        ErrorCopier ec(ac);
        if (!GetPropertyKeys(cx, env, JSITER_HIDDEN, &keys))
            return false;
    }

    RootedObject arr(cx, NewDenseEmptyArray(cx));
    if (!arr)
        return false;
    RootedId id(cx);
    for (size_t i = 0, len = keys.length(); i < len; i++) {
        id = keys[i];
        if (JSID_IS_ATOM(id) && IsIdentifier(JSID_TO_ATOM(id))) {
            if (!NewbornArrayPush(cx, arr, StringValue(JSID_TO_STRING(id))))
                return false;
        }
    }
    args.rval().setObject(*arr);
    return true;
}

static bool
DebuggerEnv_find(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGENV_OWNER(cx, argc, vp, "find", args, envobj, env, dbg);
    if (!args.requireAtLeast(cx, "Debugger.Environment.find", 1))
        return false;

    RootedId id(cx);
    if (!ValueToIdentifier(cx, args[0], &id))
        return false;

    {
        Maybe<AutoCompartment> ac;
        ac.emplace(cx, env);

        /* This can trigger resolve hooks. */
        ErrorCopier ec(ac);
        bool found;
        for (; env; env = env->enclosingScope()) {
            if (!HasProperty(cx, env, id, &found))
                return false;
            if (found)
                break;
        }
    }

    return dbg->wrapEnvironment(cx, env, args.rval());
}

static bool
DebuggerEnv_getVariable(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGENV_OWNER(cx, argc, vp, "getVariable", args, envobj, env, dbg);
    if (!args.requireAtLeast(cx, "Debugger.Environment.getVariable", 1))
        return false;

    RootedId id(cx);
    if (!ValueToIdentifier(cx, args[0], &id))
        return false;

    RootedValue v(cx);
    {
        Maybe<AutoCompartment> ac;
        ac.emplace(cx, env);

        /* This can trigger getters. */
        ErrorCopier ec(ac);

        // For DebugScopeObjects, we get sentinel values for optimized out
        // slots and arguments instead of throwing (the default behavior).
        //
        // See wrapDebuggeeValue for how the sentinel values are wrapped.
        if (env->is<DebugScopeObject>()) {
            if (!env->as<DebugScopeObject>().getMaybeSentinelValue(cx, id, &v))
                return false;
        } else {
            if (!GetProperty(cx, env, env, id, &v))
                return false;
        }
    }

    // When we've faked up scope chain objects for optimized-out scopes,
    // declarative environments may contain internal JSFunction objects, which
    // we shouldn't expose to the user.
    if (v.isObject()) {
        RootedObject obj(cx, &v.toObject());
        if (obj->is<JSFunction>() &&
            IsInternalFunctionObject(obj->as<JSFunction>()))
            v.setMagic(JS_OPTIMIZED_OUT);
    }

    if (!dbg->wrapDebuggeeValue(cx, &v))
        return false;
    args.rval().set(v);
    return true;
}

static bool
DebuggerEnv_setVariable(JSContext* cx, unsigned argc, Value* vp)
{
    THIS_DEBUGENV_OWNER(cx, argc, vp, "setVariable", args, envobj, env, dbg);
    if (!args.requireAtLeast(cx, "Debugger.Environment.setVariable", 2))
        return false;

    RootedId id(cx);
    if (!ValueToIdentifier(cx, args[0], &id))
        return false;

    RootedValue v(cx, args[1]);
    if (!dbg->unwrapDebuggeeValue(cx, &v))
        return false;

    {
        Maybe<AutoCompartment> ac;
        ac.emplace(cx, env);
        if (!cx->compartment()->wrap(cx, &v))
            return false;

        /* This can trigger setters. */
        ErrorCopier ec(ac);

        /* Make sure the environment actually has the specified binding. */
        bool has;
        if (!HasProperty(cx, env, id, &has))
            return false;
        if (!has) {
            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_VARIABLE_NOT_FOUND);
            return false;
        }

        /* Just set the property. */
        if (!SetProperty(cx, env, id, v))
            return false;
    }

    args.rval().setUndefined();
    return true;
}

static const JSPropertySpec DebuggerEnv_properties[] = {
    JS_PSG("type", DebuggerEnv_getType, 0),
    JS_PSG("object", DebuggerEnv_getObject, 0),
    JS_PSG("parent", DebuggerEnv_getParent, 0),
    JS_PSG("callee", DebuggerEnv_getCallee, 0),
    JS_PSG("inspectable", DebuggerEnv_getInspectable, 0),
    JS_PSG("optimizedOut", DebuggerEnv_getOptimizedOut, 0),
    JS_PS_END
};

static const JSFunctionSpec DebuggerEnv_methods[] = {
    JS_FN("names", DebuggerEnv_names, 0, 0),
    JS_FN("find", DebuggerEnv_find, 1, 0),
    JS_FN("getVariable", DebuggerEnv_getVariable, 1, 0),
    JS_FN("setVariable", DebuggerEnv_setVariable, 2, 0),
    JS_FS_END
};



/*** JS::dbg::Builder ****************************************************************************/

Builder::Builder(JSContext* cx, js::Debugger* debugger)
  : debuggerObject(cx, debugger->toJSObject().get()),
    debugger(debugger)
{ }


#if DEBUG
void
Builder::assertBuilt(JSObject* obj)
{
    // We can't use assertSameCompartment here, because that is always keyed to
    // some JSContext's current compartment, whereas BuiltThings can be
    // constructed and assigned to without respect to any particular context;
    // the only constraint is that they should be in their debugger's compartment.
    MOZ_ASSERT_IF(obj, debuggerObject->compartment() == obj->compartment());
}
#endif

bool
Builder::Object::definePropertyToTrusted(JSContext* cx, const char* name,
                                         JS::MutableHandleValue trusted)
{
    // We should have checked for false Objects before calling this.
    MOZ_ASSERT(value);

    JSAtom* atom = Atomize(cx, name, strlen(name));
    if (!atom)
        return false;
    RootedId id(cx, AtomToId(atom));

    return DefineProperty(cx, value, id, trusted);
}

bool
Builder::Object::defineProperty(JSContext* cx, const char* name, JS::HandleValue propval_)
{
    AutoCompartment ac(cx, debuggerObject());

    RootedValue propval(cx, propval_);
    if (!debugger()->wrapDebuggeeValue(cx, &propval))
        return false;

    return definePropertyToTrusted(cx, name, &propval);
}

bool
Builder::Object::defineProperty(JSContext* cx, const char* name, JS::HandleObject propval_)
{
    RootedValue propval(cx, ObjectOrNullValue(propval_));
    return defineProperty(cx, name, propval);
}

bool
Builder::Object::defineProperty(JSContext* cx, const char* name, Builder::Object& propval_)
{
    AutoCompartment ac(cx, debuggerObject());

    RootedValue propval(cx, ObjectOrNullValue(propval_.value));
    return definePropertyToTrusted(cx, name, &propval);
}

Builder::Object
Builder::newObject(JSContext* cx)
{
    AutoCompartment ac(cx, debuggerObject);

    RootedPlainObject obj(cx, NewBuiltinClassInstance<PlainObject>(cx));

    // If the allocation failed, this will return a false Object, as the spec promises.
    return Object(cx, *this, obj);
}


/*** JS::dbg::AutoEntryMonitor ******************************************************************/

AutoEntryMonitor::AutoEntryMonitor(JSContext* cx)
  : runtime_(cx->runtime()),
    savedMonitor_(cx->runtime()->entryMonitor)
{
    runtime_->entryMonitor = this;
}

AutoEntryMonitor::~AutoEntryMonitor()
{
    runtime_->entryMonitor = savedMonitor_;
}


/*** Glue ****************************************************************************************/

extern JS_PUBLIC_API(bool)
JS_DefineDebuggerObject(JSContext* cx, HandleObject obj)
{
    RootedNativeObject
        objProto(cx),
        debugCtor(cx),
        debugProto(cx),
        frameProto(cx),
        scriptProto(cx),
        sourceProto(cx),
        objectProto(cx),
        envProto(cx),
        memoryProto(cx);
    objProto = obj->as<GlobalObject>().getOrCreateObjectPrototype(cx);
    if (!objProto)
        return false;
    debugProto = InitClass(cx, obj,
                           objProto, &Debugger::jsclass, Debugger::construct,
                           1, Debugger::properties, Debugger::methods, nullptr, nullptr,
                           debugCtor.address());
    if (!debugProto)
        return false;

    frameProto = InitClass(cx, debugCtor, objProto, &DebuggerFrame_class,
                           DebuggerFrame_construct, 0,
                           DebuggerFrame_properties, DebuggerFrame_methods,
                           nullptr, nullptr);
    if (!frameProto)
        return false;

    scriptProto = InitClass(cx, debugCtor, objProto, &DebuggerScript_class,
                            DebuggerScript_construct, 0,
                            DebuggerScript_properties, DebuggerScript_methods,
                            nullptr, nullptr);
    if (!scriptProto)
        return false;

    sourceProto = InitClass(cx, debugCtor, sourceProto, &DebuggerSource_class,
                            DebuggerSource_construct, 0,
                            DebuggerSource_properties, DebuggerSource_methods,
                            nullptr, nullptr);
    if (!sourceProto)
        return false;

    objectProto = InitClass(cx, debugCtor, objProto, &DebuggerObject_class,
                            DebuggerObject_construct, 0,
                            DebuggerObject_properties, DebuggerObject_methods,
                            nullptr, nullptr);
    if (!objectProto)
        return false;
    envProto = InitClass(cx, debugCtor, objProto, &DebuggerEnv_class,
                         DebuggerEnv_construct, 0,
                         DebuggerEnv_properties, DebuggerEnv_methods,
                         nullptr, nullptr);
    if (!envProto)
        return false;
    memoryProto = InitClass(cx, debugCtor, objProto, &DebuggerMemory::class_,
                            DebuggerMemory::construct, 0, DebuggerMemory::properties,
                            DebuggerMemory::methods, nullptr, nullptr);
    if (!memoryProto)
        return false;

    debugProto->setReservedSlot(Debugger::JSSLOT_DEBUG_FRAME_PROTO, ObjectValue(*frameProto));
    debugProto->setReservedSlot(Debugger::JSSLOT_DEBUG_OBJECT_PROTO, ObjectValue(*objectProto));
    debugProto->setReservedSlot(Debugger::JSSLOT_DEBUG_SCRIPT_PROTO, ObjectValue(*scriptProto));
    debugProto->setReservedSlot(Debugger::JSSLOT_DEBUG_SOURCE_PROTO, ObjectValue(*sourceProto));
    debugProto->setReservedSlot(Debugger::JSSLOT_DEBUG_ENV_PROTO, ObjectValue(*envProto));
    debugProto->setReservedSlot(Debugger::JSSLOT_DEBUG_MEMORY_PROTO, ObjectValue(*memoryProto));
    return true;
}

static inline void
AssertIsPromise(JSContext* cx, HandleObject promise)
{
    MOZ_ASSERT(promise);
    assertSameCompartment(cx, promise);
    MOZ_ASSERT(strcmp(promise->getClass()->name, "Promise") == 0 ||
               strcmp(promise->getClass()->name, "MozAbortablePromise") == 0);
}

JS_PUBLIC_API(void)
JS::dbg::onNewPromise(JSContext* cx, HandleObject promise)
{
    AssertIsPromise(cx, promise);
    Debugger::slowPathPromiseHook(cx, Debugger::OnNewPromise, promise);
}

JS_PUBLIC_API(void)
JS::dbg::onPromiseSettled(JSContext* cx, HandleObject promise)
{
    AssertIsPromise(cx, promise);
    Debugger::slowPathPromiseHook(cx, Debugger::OnPromiseSettled, promise);
}

JS_PUBLIC_API(bool)
JS::dbg::IsDebugger(JSObject& obj)
{
    JSObject* unwrapped = CheckedUnwrap(&obj);
    return unwrapped &&
           js::GetObjectClass(unwrapped) == &Debugger::jsclass &&
           js::Debugger::fromJSObject(unwrapped) != nullptr;
}

JS_PUBLIC_API(bool)
JS::dbg::GetDebuggeeGlobals(JSContext* cx, JSObject& dbgObj, AutoObjectVector& vector)
{
    MOZ_ASSERT(IsDebugger(dbgObj));
    js::Debugger* dbg = js::Debugger::fromJSObject(CheckedUnwrap(&dbgObj));

    if (!vector.reserve(vector.length() + dbg->debuggees.count())) {
        JS_ReportOutOfMemory(cx);
        return false;
    }

    for (WeakGlobalObjectSet::Range r = dbg->allDebuggees(); !r.empty(); r.popFront())
        vector.infallibleAppend(static_cast<JSObject*>(r.front()));

    return true;
}


/*** JS::dbg::GarbageCollectionEvent **************************************************************/

namespace JS {
namespace dbg {

/* static */ GarbageCollectionEvent::Ptr
GarbageCollectionEvent::Create(JSRuntime* rt, ::js::gcstats::Statistics& stats, uint64_t gcNumber)
{
    auto data = rt->make_unique<GarbageCollectionEvent>(gcNumber);
    if (!data)
        return nullptr;

    data->nonincrementalReason = stats.nonincrementalReason();

    for (auto range = stats.sliceRange(); !range.empty(); range.popFront()) {
        if (!data->reason) {
            // There is only one GC reason for the whole cycle, but for legacy
            // reasons this data is stored and replicated on each slice. Each
            // slice used to have its own GCReason, but now they are all the
            // same.
            data->reason = gcstats::ExplainReason(range.front().reason);
            MOZ_ASSERT(data->reason);
        }

        if (!data->collections.growBy(1))
            return nullptr;

        data->collections.back().startTimestamp = range.front().startTimestamp;
        data->collections.back().endTimestamp = range.front().endTimestamp;
    }


    return data;
}

static bool
DefineStringProperty(JSContext* cx, HandleObject obj, PropertyName* propName, const char* strVal)
{
    RootedValue val(cx, UndefinedValue());
    if (strVal) {
        JSAtom* atomized = Atomize(cx, strVal, strlen(strVal));
        if (!atomized)
            return false;
        val = StringValue(atomized);
    }
    return DefineProperty(cx, obj, propName, val);
}

JSObject*
GarbageCollectionEvent::toJSObject(JSContext* cx) const
{
    RootedObject obj(cx, NewBuiltinClassInstance<PlainObject>(cx));
    RootedValue gcCycleNumberVal(cx, NumberValue(majorGCNumber_));
    if (!obj ||
        !DefineStringProperty(cx, obj, cx->names().nonincrementalReason, nonincrementalReason) ||
        !DefineStringProperty(cx, obj, cx->names().reason, reason) ||
        !DefineProperty(cx, obj, cx->names().gcCycleNumber, gcCycleNumberVal))
    {
        return nullptr;
    }

    RootedArrayObject slicesArray(cx, NewDenseEmptyArray(cx));
    if (!slicesArray)
        return nullptr;

    size_t idx = 0;
    for (auto range = collections.all(); !range.empty(); range.popFront()) {
        RootedPlainObject collectionObj(cx, NewBuiltinClassInstance<PlainObject>(cx));
        if (!collectionObj)
            return nullptr;

        RootedValue start(cx, NumberValue(range.front().startTimestamp));
        RootedValue end(cx, NumberValue(range.front().endTimestamp));
        if (!DefineProperty(cx, collectionObj, cx->names().startTimestamp, start) ||
            !DefineProperty(cx, collectionObj, cx->names().endTimestamp, end))
        {
            return nullptr;
        }

        RootedValue collectionVal(cx, ObjectValue(*collectionObj));
        if (!DefineElement(cx, slicesArray, idx++, collectionVal))
            return nullptr;
    }

    RootedValue slicesValue(cx, ObjectValue(*slicesArray));
    if (!DefineProperty(cx, obj, cx->names().collections, slicesValue))
        return nullptr;

    return obj;
}

JS_PUBLIC_API(bool)
FireOnGarbageCollectionHook(JSContext* cx, JS::dbg::GarbageCollectionEvent::Ptr&& data)
{
    AutoObjectVector triggered(cx);

    {
        // We had better not GC (and potentially get a dangling Debugger
        // pointer) while finding all Debuggers observing a debuggee that
        // participated in this GC.
        AutoCheckCannotGC noGC;

        for (Debugger* dbg = cx->runtime()->debuggerList.getFirst(); dbg; dbg = dbg->getNext()) {
            if (dbg->enabled &&
                dbg->observedGC(data->majorGCNumber()) &&
                dbg->getHook(Debugger::OnGarbageCollection))
            {
                if (!triggered.append(dbg->object)) {
                    JS_ReportOutOfMemory(cx);
                    return false;
                }
            }
        }
    }

    for ( ; !triggered.empty(); triggered.popBack()) {
        Debugger* dbg = Debugger::fromJSObject(triggered.back());
        dbg->fireOnGarbageCollectionHook(cx, data);
        MOZ_ASSERT(!cx->isExceptionPending());
    }

    return true;
}

} // namespace dbg
} // namespace JS
