js/public/GCAPI.h
author Masayuki Nakano <masayuki@d-toybox.com>
Fri, 19 May 2017 17:49:41 +0900
changeset 359318 b75c111837a802ceb953dba50a3c5a193d53ca22
parent 358801 973df75647b595b6cbc0d93f97a7cbda38acfeec
child 360392 9414aca02ae0b28fa55d84d624181e754f4cc066
permissions -rw-r--r--
Bug 1339543 part 4 Change nsIWidget::ExecuteNativeKeyBinding() to nsIWidget::GetEditCommands() which just retrieves edit commands for the type r=smaug Now, nsIWidget::ExecuteNativeKeyBinding() isn't used by anybody for executing edit commands. Instead, they need array of edit commands for the key combination. So, the method should be renamed to GetEditCommands() and just return edit commands as an array. MozReview-Commit-ID: 4G0B1lJ8Lbe

/* -*- 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/. */

#ifndef js_GCAPI_h
#define js_GCAPI_h

#include "mozilla/TimeStamp.h"
#include "mozilla/Vector.h"

#include "js/GCAnnotations.h"
#include "js/HeapAPI.h"
#include "js/UniquePtr.h"
#include "js/Utility.h"

namespace js {
namespace gc {
class GCRuntime;
} // namespace gc
namespace gcstats {
struct Statistics;
} // namespace gcstats
} // namespace js

typedef enum JSGCMode {
    /** Perform only global GCs. */
    JSGC_MODE_GLOBAL = 0,

    /** Perform per-zone GCs until too much garbage has accumulated. */
    JSGC_MODE_ZONE = 1,

    /**
     * Collect in short time slices rather than all at once. Implies
     * JSGC_MODE_ZONE.
     */
    JSGC_MODE_INCREMENTAL = 2
} JSGCMode;

/**
 * Kinds of js_GC invocation.
 */
typedef enum JSGCInvocationKind {
    /* Normal invocation. */
    GC_NORMAL = 0,

    /* Minimize GC triggers and release empty GC chunks right away. */
    GC_SHRINK = 1
} JSGCInvocationKind;

namespace JS {

#define GCREASONS(D)                            \
    /* Reasons internal to the JS engine */     \
    D(API)                                      \
    D(EAGER_ALLOC_TRIGGER)                      \
    D(DESTROY_RUNTIME)                          \
    D(UNUSED0)                                  \
    D(LAST_DITCH)                               \
    D(TOO_MUCH_MALLOC)                          \
    D(ALLOC_TRIGGER)                            \
    D(DEBUG_GC)                                 \
    D(COMPARTMENT_REVIVED)                      \
    D(RESET)                                    \
    D(OUT_OF_NURSERY)                           \
    D(EVICT_NURSERY)                            \
    D(FULL_STORE_BUFFER)                        \
    D(SHARED_MEMORY_LIMIT)                      \
    D(UNUSED1)                                  \
    D(INCREMENTAL_TOO_SLOW)                     \
    D(ABORT_GC)                                 \
                                                \
    /* These are reserved for future use. */    \
    D(RESERVED0)                                \
    D(RESERVED1)                                \
    D(RESERVED2)                                \
    D(RESERVED3)                                \
    D(RESERVED4)                                \
    D(RESERVED5)                                \
    D(RESERVED6)                                \
    D(RESERVED7)                                \
    D(RESERVED8)                                \
    D(RESERVED9)                                \
    D(RESERVED10)                               \
    D(RESERVED11)                               \
    D(RESERVED12)                               \
    D(RESERVED13)                               \
    D(RESERVED14)                               \
    D(RESERVED15)                               \
                                                \
    /* Reasons from Firefox */                  \
    D(DOM_WINDOW_UTILS)                         \
    D(COMPONENT_UTILS)                          \
    D(MEM_PRESSURE)                             \
    D(CC_WAITING)                               \
    D(CC_FORCED)                                \
    D(LOAD_END)                                 \
    D(POST_COMPARTMENT)                         \
    D(PAGE_HIDE)                                \
    D(NSJSCONTEXT_DESTROY)                      \
    D(SET_NEW_DOCUMENT)                         \
    D(SET_DOC_SHELL)                            \
    D(DOM_UTILS)                                \
    D(DOM_IPC)                                  \
    D(DOM_WORKER)                               \
    D(INTER_SLICE_GC)                           \
    D(REFRESH_FRAME)                            \
    D(FULL_GC_TIMER)                            \
    D(SHUTDOWN_CC)                              \
    D(FINISH_LARGE_EVALUATE)                    \
    D(USER_INACTIVE)                            \
    D(XPCONNECT_SHUTDOWN)

namespace gcreason {

/* GCReasons will end up looking like JSGC_MAYBEGC */
enum Reason {
#define MAKE_REASON(name) name,
    GCREASONS(MAKE_REASON)
#undef MAKE_REASON
    NO_REASON,
    NUM_REASONS,

    /*
     * For telemetry, we want to keep a fixed max bucket size over time so we
     * don't have to switch histograms. 100 is conservative; as of this writing
     * there are 52. But the cost of extra buckets seems to be low while the
     * cost of switching histograms is high.
     */
    NUM_TELEMETRY_REASONS = 100
};

/**
 * Get a statically allocated C string explaining the given GC reason.
 */
extern JS_PUBLIC_API(const char*)
ExplainReason(JS::gcreason::Reason reason);

} /* namespace gcreason */

/*
 * Zone GC:
 *
 * SpiderMonkey's GC is capable of performing a collection on an arbitrary
 * subset of the zones in the system. This allows an embedding to minimize
 * collection time by only collecting zones that have run code recently,
 * ignoring the parts of the heap that are unlikely to have changed.
 *
 * When triggering a GC using one of the functions below, it is first necessary
 * to select the zones to be collected. To do this, you can call
 * PrepareZoneForGC on each zone, or you can call PrepareForFullGC to select
 * all zones. Failing to select any zone is an error.
 */

/**
 * Schedule the given zone to be collected as part of the next GC.
 */
extern JS_PUBLIC_API(void)
PrepareZoneForGC(Zone* zone);

/**
 * Schedule all zones to be collected in the next GC.
 */
extern JS_PUBLIC_API(void)
PrepareForFullGC(JSContext* cx);

/**
 * When performing an incremental GC, the zones that were selected for the
 * previous incremental slice must be selected in subsequent slices as well.
 * This function selects those slices automatically.
 */
extern JS_PUBLIC_API(void)
PrepareForIncrementalGC(JSContext* cx);

/**
 * Returns true if any zone in the system has been scheduled for GC with one of
 * the functions above or by the JS engine.
 */
extern JS_PUBLIC_API(bool)
IsGCScheduled(JSContext* cx);

/**
 * Undoes the effect of the Prepare methods above. The given zone will not be
 * collected in the next GC.
 */
extern JS_PUBLIC_API(void)
SkipZoneForGC(Zone* zone);

/*
 * Non-Incremental GC:
 *
 * The following functions perform a non-incremental GC.
 */

/**
 * Performs a non-incremental collection of all selected zones.
 *
 * If the gckind argument is GC_NORMAL, then some objects that are unreachable
 * from the program may still be alive afterwards because of internal
 * references; if GC_SHRINK is passed then caches and other temporary references
 * to objects will be cleared and all unreferenced objects will be removed from
 * the system.
 */
extern JS_PUBLIC_API(void)
GCForReason(JSContext* cx, JSGCInvocationKind gckind, gcreason::Reason reason);

/*
 * Incremental GC:
 *
 * Incremental GC divides the full mark-and-sweep collection into multiple
 * slices, allowing client JavaScript code to run between each slice. This
 * allows interactive apps to avoid long collection pauses. Incremental GC does
 * not make collection take less time, it merely spreads that time out so that
 * the pauses are less noticable.
 *
 * For a collection to be carried out incrementally the following conditions
 * must be met:
 *  - The collection must be run by calling JS::IncrementalGC() rather than
 *    JS_GC().
 *  - The GC mode must have been set to JSGC_MODE_INCREMENTAL with
 *    JS_SetGCParameter().
 *
 * Note: Even if incremental GC is enabled and working correctly,
 *       non-incremental collections can still happen when low on memory.
 */

/**
 * Begin an incremental collection and perform one slice worth of work. When
 * this function returns, the collection may not be complete.
 * IncrementalGCSlice() must be called repeatedly until
 * !IsIncrementalGCInProgress(cx).
 *
 * Note: SpiderMonkey's GC is not realtime. Slices in practice may be longer or
 *       shorter than the requested interval.
 */
extern JS_PUBLIC_API(void)
StartIncrementalGC(JSContext* cx, JSGCInvocationKind gckind, gcreason::Reason reason,
                   int64_t millis = 0);

/**
 * Perform a slice of an ongoing incremental collection. When this function
 * returns, the collection may not be complete. It must be called repeatedly
 * until !IsIncrementalGCInProgress(cx).
 *
 * Note: SpiderMonkey's GC is not realtime. Slices in practice may be longer or
 *       shorter than the requested interval.
 */
extern JS_PUBLIC_API(void)
IncrementalGCSlice(JSContext* cx, gcreason::Reason reason, int64_t millis = 0);

/**
 * If IsIncrementalGCInProgress(cx), this call finishes the ongoing collection
 * by performing an arbitrarily long slice. If !IsIncrementalGCInProgress(cx),
 * this is equivalent to GCForReason. When this function returns,
 * IsIncrementalGCInProgress(cx) will always be false.
 */
extern JS_PUBLIC_API(void)
FinishIncrementalGC(JSContext* cx, gcreason::Reason reason);

/**
 * If IsIncrementalGCInProgress(cx), this call aborts the ongoing collection and
 * performs whatever work needs to be done to return the collector to its idle
 * state. This may take an arbitrarily long time. When this function returns,
 * IsIncrementalGCInProgress(cx) will always be false.
 */
extern JS_PUBLIC_API(void)
AbortIncrementalGC(JSContext* cx);

namespace dbg {

// The `JS::dbg::GarbageCollectionEvent` class is essentially a view of the
// `js::gcstats::Statistics` data without the uber implementation-specific bits.
// It should generally be palatable for web developers.
class GarbageCollectionEvent
{
    // The major GC number of the GC cycle this data pertains to.
    uint64_t majorGCNumber_;

    // Reference to a non-owned, statically allocated C string. This is a very
    // short reason explaining why a GC was triggered.
    const char* reason;

    // Reference to a nullable, non-owned, statically allocated C string. If the
    // collection was forced to be non-incremental, this is a short reason of
    // why the GC could not perform an incremental collection.
    const char* nonincrementalReason;

    // Represents a single slice of a possibly multi-slice incremental garbage
    // collection.
    struct Collection {
        mozilla::TimeStamp startTimestamp;
        mozilla::TimeStamp endTimestamp;
    };

    // The set of garbage collection slices that made up this GC cycle.
    mozilla::Vector<Collection> collections;

    GarbageCollectionEvent(const GarbageCollectionEvent& rhs) = delete;
    GarbageCollectionEvent& operator=(const GarbageCollectionEvent& rhs) = delete;

  public:
    explicit GarbageCollectionEvent(uint64_t majorGCNum)
        : majorGCNumber_(majorGCNum)
        , reason(nullptr)
        , nonincrementalReason(nullptr)
        , collections()
    { }

    using Ptr = js::UniquePtr<GarbageCollectionEvent>;
    static Ptr Create(JSRuntime* rt, ::js::gcstats::Statistics& stats, uint64_t majorGCNumber);

    JSObject* toJSObject(JSContext* cx) const;

    uint64_t majorGCNumber() const { return majorGCNumber_; }
};

} // namespace dbg

enum GCProgress {
    /*
     * During GC, the GC is bracketed by GC_CYCLE_BEGIN/END callbacks. Each
     * slice between those (whether an incremental or the sole non-incremental
     * slice) is bracketed by GC_SLICE_BEGIN/GC_SLICE_END.
     */

    GC_CYCLE_BEGIN,
    GC_SLICE_BEGIN,
    GC_SLICE_END,
    GC_CYCLE_END
};

struct JS_PUBLIC_API(GCDescription) {
    bool isZone_;
    bool isComplete_;
    JSGCInvocationKind invocationKind_;
    gcreason::Reason reason_;

    GCDescription(bool isZone, bool isComplete, JSGCInvocationKind kind, gcreason::Reason reason)
      : isZone_(isZone), isComplete_(isComplete), invocationKind_(kind), reason_(reason) {}

    char16_t* formatSliceMessage(JSContext* cx) const;
    char16_t* formatSummaryMessage(JSContext* cx) const;
    char16_t* formatJSON(JSContext* cx, uint64_t timestamp) const;

    mozilla::TimeStamp startTime(JSContext* cx) const;
    mozilla::TimeStamp endTime(JSContext* cx) const;
    mozilla::TimeStamp lastSliceStart(JSContext* cx) const;
    mozilla::TimeStamp lastSliceEnd(JSContext* cx) const;

    JS::UniqueChars sliceToJSON(JSContext* cx) const;
    JS::UniqueChars summaryToJSON(JSContext* cx) const;

    JS::dbg::GarbageCollectionEvent::Ptr toGCEvent(JSContext* cx) const;
};

extern JS_PUBLIC_API(UniqueChars)
MinorGcToJSON(JSContext* cx);

typedef void
(* GCSliceCallback)(JSContext* cx, GCProgress progress, const GCDescription& desc);

/**
 * The GC slice callback is called at the beginning and end of each slice. This
 * callback may be used for GC notifications as well as to perform additional
 * marking.
 */
extern JS_PUBLIC_API(GCSliceCallback)
SetGCSliceCallback(JSContext* cx, GCSliceCallback callback);

/**
 * Describes the progress of an observed nursery collection.
 */
enum class GCNurseryProgress {
    /**
     * The nursery collection is starting.
     */
    GC_NURSERY_COLLECTION_START,
    /**
     * The nursery collection is ending.
     */
    GC_NURSERY_COLLECTION_END
};

/**
 * A nursery collection callback receives the progress of the nursery collection
 * and the reason for the collection.
 */
using GCNurseryCollectionCallback = void(*)(JSContext* cx, GCNurseryProgress progress,
                                            gcreason::Reason reason);

/**
 * Set the nursery collection callback for the given runtime. When set, it will
 * be called at the start and end of every nursery collection.
 */
extern JS_PUBLIC_API(GCNurseryCollectionCallback)
SetGCNurseryCollectionCallback(JSContext* cx, GCNurseryCollectionCallback callback);

typedef void
(* DoCycleCollectionCallback)(JSContext* cx);

/**
 * The purge gray callback is called after any COMPARTMENT_REVIVED GC in which
 * the majority of compartments have been marked gray.
 */
extern JS_PUBLIC_API(DoCycleCollectionCallback)
SetDoCycleCollectionCallback(JSContext* cx, DoCycleCollectionCallback callback);

/**
 * Incremental GC defaults to enabled, but may be disabled for testing or in
 * embeddings that have not yet implemented barriers on their native classes.
 * There is not currently a way to re-enable incremental GC once it has been
 * disabled on the runtime.
 */
extern JS_PUBLIC_API(void)
DisableIncrementalGC(JSContext* cx);

/**
 * Returns true if incremental GC is enabled. Simply having incremental GC
 * enabled is not sufficient to ensure incremental collections are happening.
 * See the comment "Incremental GC" above for reasons why incremental GC may be
 * suppressed. Inspection of the "nonincremental reason" field of the
 * GCDescription returned by GCSliceCallback may help narrow down the cause if
 * collections are not happening incrementally when expected.
 */
extern JS_PUBLIC_API(bool)
IsIncrementalGCEnabled(JSContext* cx);

/**
 * Returns true while an incremental GC is ongoing, both when actively
 * collecting and between slices.
 */
extern JS_PUBLIC_API(bool)
IsIncrementalGCInProgress(JSContext* cx);

/**
 * Returns true while an incremental GC is ongoing, both when actively
 * collecting and between slices.
 */
extern JS_PUBLIC_API(bool)
IsIncrementalGCInProgress(JSRuntime* rt);

/*
 * Returns true when writes to GC thing pointers (and reads from weak pointers)
 * must call an incremental barrier. This is generally only true when running
 * mutator code in-between GC slices. At other times, the barrier may be elided
 * for performance.
 */
extern JS_PUBLIC_API(bool)
IsIncrementalBarrierNeeded(JSContext* cx);

/*
 * Notify the GC that a reference to a JSObject is about to be overwritten.
 * This method must be called if IsIncrementalBarrierNeeded.
 */
extern JS_PUBLIC_API(void)
IncrementalPreWriteBarrier(JSObject* obj);

/*
 * Notify the GC that a weak reference to a GC thing has been read.
 * This method must be called if IsIncrementalBarrierNeeded.
 */
extern JS_PUBLIC_API(void)
IncrementalReadBarrier(GCCellPtr thing);

/**
 * Returns true if the most recent GC ran incrementally.
 */
extern JS_PUBLIC_API(bool)
WasIncrementalGC(JSRuntime* rt);

/*
 * Generational GC:
 *
 * Note: Generational GC is not yet enabled by default. The following class
 *       is non-functional unless SpiderMonkey was configured with
 *       --enable-gcgenerational.
 */

/** Ensure that generational GC is disabled within some scope. */
class JS_PUBLIC_API(AutoDisableGenerationalGC)
{
    JSContext* cx;

  public:
    explicit AutoDisableGenerationalGC(JSContext* cx);
    ~AutoDisableGenerationalGC();
};

/**
 * Returns true if generational allocation and collection is currently enabled
 * on the given runtime.
 */
extern JS_PUBLIC_API(bool)
IsGenerationalGCEnabled(JSRuntime* rt);

/**
 * Returns the GC's "number". This does not correspond directly to the number
 * of GCs that have been run, but is guaranteed to be monotonically increasing
 * with GC activity.
 */
extern JS_PUBLIC_API(size_t)
GetGCNumber();

/**
 * Pass a subclass of this "abstract" class to callees to require that they
 * never GC. Subclasses can use assertions or the hazard analysis to ensure no
 * GC happens.
 */
class JS_PUBLIC_API(AutoRequireNoGC)
{
  protected:
    AutoRequireNoGC() {}
    ~AutoRequireNoGC() {}
};

/**
 * Diagnostic assert (see MOZ_DIAGNOSTIC_ASSERT) that GC cannot occur while this
 * class is live. This class does not disable the static rooting hazard
 * analysis.
 *
 * This works by entering a GC unsafe region, which is checked on allocation and
 * on GC.
 */
class JS_PUBLIC_API(AutoAssertNoGC) : public AutoRequireNoGC
{
    JSContext* cx_;

  public:
    explicit AutoAssertNoGC(JSContext* cx = nullptr);
    ~AutoAssertNoGC();
};

/**
 * Assert if an allocation of a GC thing occurs while this class is live. This
 * class does not disable the static rooting hazard analysis.
 */
class JS_PUBLIC_API(AutoAssertNoAlloc)
{
#ifdef JS_DEBUG
    js::gc::GCRuntime* gc;

  public:
    AutoAssertNoAlloc() : gc(nullptr) {}
    explicit AutoAssertNoAlloc(JSContext* cx);
    void disallowAlloc(JSRuntime* rt);
    ~AutoAssertNoAlloc();
#else
  public:
    AutoAssertNoAlloc() {}
    explicit AutoAssertNoAlloc(JSContext* cx) {}
    void disallowAlloc(JSRuntime* rt) {}
#endif
};

/**
 * Assert if a GC barrier is invoked while this class is live. This class does
 * not disable the static rooting hazard analysis.
 */
class JS_PUBLIC_API(AutoAssertOnBarrier)
{
    JSContext* context;
    bool prev;

  public:
    explicit AutoAssertOnBarrier(JSContext* cx);
    ~AutoAssertOnBarrier();
};

/**
 * Disable the static rooting hazard analysis in the live region and assert if
 * any allocation that could potentially trigger a GC occurs while this guard
 * object is live. This is most useful to help the exact rooting hazard analysis
 * in complex regions, since it cannot understand dataflow.
 *
 * Note: GC behavior is unpredictable even when deterministic and is generally
 *       non-deterministic in practice. The fact that this guard has not
 *       asserted is not a guarantee that a GC cannot happen in the guarded
 *       region. As a rule, anyone performing a GC unsafe action should
 *       understand the GC properties of all code in that region and ensure
 *       that the hazard analysis is correct for that code, rather than relying
 *       on this class.
 */
class JS_PUBLIC_API(AutoSuppressGCAnalysis) : public AutoAssertNoAlloc
{
  public:
    AutoSuppressGCAnalysis() : AutoAssertNoAlloc() {}
    explicit AutoSuppressGCAnalysis(JSContext* cx) : AutoAssertNoAlloc(cx) {}
} JS_HAZ_GC_SUPPRESSED;

/**
 * Assert that code is only ever called from a GC callback, disable the static
 * rooting hazard analysis and assert if any allocation that could potentially
 * trigger a GC occurs while this guard object is live.
 *
 * This is useful to make the static analysis ignore code that runs in GC
 * callbacks.
 */
class JS_PUBLIC_API(AutoAssertGCCallback) : public AutoSuppressGCAnalysis
{
  public:
#ifdef DEBUG
    AutoAssertGCCallback();
#else
    AutoAssertGCCallback() {}
#endif
};

/**
 * Place AutoCheckCannotGC in scopes that you believe can never GC. These
 * annotations will be verified both dynamically via AutoAssertNoGC, and
 * statically with the rooting hazard analysis (implemented by making the
 * analysis consider AutoCheckCannotGC to be a GC pointer, and therefore
 * complain if it is live across a GC call.) It is useful when dealing with
 * internal pointers to GC things where the GC thing itself may not be present
 * for the static analysis: e.g. acquiring inline chars from a JSString* on the
 * heap.
 *
 * We only do the assertion checking in DEBUG builds.
 */
#ifdef DEBUG
class JS_PUBLIC_API(AutoCheckCannotGC) : public AutoAssertNoGC
{
  public:
    explicit AutoCheckCannotGC(JSContext* cx = nullptr) : AutoAssertNoGC(cx) {}
} JS_HAZ_GC_INVALIDATED;
#else
class JS_PUBLIC_API(AutoCheckCannotGC) : public AutoRequireNoGC
{
  public:
    explicit AutoCheckCannotGC(JSContext* cx = nullptr) {}
} JS_HAZ_GC_INVALIDATED;
#endif

/**
 * Unsets the gray bit for anything reachable from |thing|. |kind| should not be
 * JS::TraceKind::Shape. |thing| should be non-null. The return value indicates
 * if anything was unmarked.
 */
extern JS_FRIEND_API(bool)
UnmarkGrayGCThingRecursively(GCCellPtr thing);

} /* namespace JS */

namespace js {
namespace gc {

extern JS_FRIEND_API(bool)
BarriersAreAllowedOnCurrentThread();

static MOZ_ALWAYS_INLINE void
ExposeGCThingToActiveJS(JS::GCCellPtr thing)
{
    // GC things residing in the nursery cannot be gray: they have no mark bits.
    // All live objects in the nursery are moved to tenured at the beginning of
    // each GC slice, so the gray marker never sees nursery things.
    if (IsInsideNursery(thing.asCell()))
        return;

    // There's nothing to do for permanent GC things that might be owned by
    // another runtime.
    if (thing.mayBeOwnedByOtherRuntime())
        return;

    MOZ_DIAGNOSTIC_ASSERT(BarriersAreAllowedOnCurrentThread());

    if (IsIncrementalBarrierNeededOnTenuredGCThing(thing))
        JS::IncrementalReadBarrier(thing);
    else if (js::gc::detail::TenuredCellIsMarkedGray(thing.asCell()))
        JS::UnmarkGrayGCThingRecursively(thing);

    MOZ_ASSERT(!js::gc::detail::TenuredCellIsMarkedGray(thing.asCell()));
}

template <typename T>
extern JS_PUBLIC_API(bool)
EdgeNeedsSweepUnbarrieredSlow(T* thingp);

static MOZ_ALWAYS_INLINE bool
EdgeNeedsSweepUnbarriered(JSObject** objp)
{
    // This function does not handle updating nursery pointers. Raw JSObject
    // pointers should be updated separately or replaced with
    // JS::Heap<JSObject*> which handles this automatically.
    MOZ_ASSERT(!JS::CurrentThreadIsHeapMinorCollecting());
    if (IsInsideNursery(reinterpret_cast<Cell*>(*objp)))
        return false;

    auto zone = JS::shadow::Zone::asShadowZone(detail::GetGCThingZone(uintptr_t(*objp)));
    if (!zone->isGCSweepingOrCompacting())
        return false;

    return EdgeNeedsSweepUnbarrieredSlow(objp);
}

} /* namespace gc */
} /* namespace js */

namespace JS {

/*
 * This should be called when an object that is marked gray is exposed to the JS
 * engine (by handing it to running JS code or writing it into live JS
 * data). During incremental GC, since the gray bits haven't been computed yet,
 * we conservatively mark the object black.
 */
static MOZ_ALWAYS_INLINE void
ExposeObjectToActiveJS(JSObject* obj)
{
    MOZ_ASSERT(obj);
    MOZ_ASSERT(!js::gc::EdgeNeedsSweepUnbarrieredSlow(&obj));
    js::gc::ExposeGCThingToActiveJS(GCCellPtr(obj));
}

static MOZ_ALWAYS_INLINE void
ExposeScriptToActiveJS(JSScript* script)
{
    MOZ_ASSERT(!js::gc::EdgeNeedsSweepUnbarrieredSlow(&script));
    js::gc::ExposeGCThingToActiveJS(GCCellPtr(script));
}

/*
 * Internal to Firefox.
 *
 * Note: this is not related to the PokeGC in nsJSEnvironment.
 */
extern JS_FRIEND_API(void)
PokeGC(JSContext* cx);

/*
 * Internal to Firefox.
 */
extern JS_FRIEND_API(void)
NotifyDidPaint(JSContext* cx);

} /* namespace JS */

#endif /* js_GCAPI_h */