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/* -*- 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 jsgcinlines_h
#define jsgcinlines_h

#include "jsgc.h"

#include "gc/Zone.h"

namespace js {

class Shape;

/*
 * This auto class should be used around any code that might cause a mark bit to
 * be set on an object in a dead zone. See AutoMaybeTouchDeadZones
 * for more details.
 */
struct AutoMarkInDeadZone
{
    AutoMarkInDeadZone(JS::Zone* zone)
      : zone(zone),
        scheduled(zone->scheduledForDestruction)
    {
        JSRuntime* rt = zone->runtimeFromMainThread();
        if (rt->gcManipulatingDeadZones && zone->scheduledForDestruction) {
            rt->gcObjectsMarkedInDeadZones++;
            zone->scheduledForDestruction = false;
        }
    }

    ~AutoMarkInDeadZone() {
        zone->scheduledForDestruction = scheduled;
    }

  private:
    JS::Zone* zone;
    bool scheduled;
};

inline Allocator* const
ThreadSafeContext::allocator()
{
    JS_ASSERT_IF(isJSContext(), &asJSContext()->zone()->allocator == allocator_);
    return allocator_;
}

template <typename T>
inline bool
ThreadSafeContext::isThreadLocal(T thing) const
{
    if (!isForkJoinContext())
        return true;

    if (!IsInsideNursery(runtime_, thing) &&
        allocator_->arenas.containsArena(runtime_, thing->arenaHeader()))
    {
        // GC should be suppressed in preparation for mutating thread local
        // objects, as we don't want to trip any barriers.
        JS_ASSERT(!thing->zoneFromAnyThread()->needsBarrier());
        JS_ASSERT(!thing->runtimeFromAnyThread()->needsBarrier());

        return true;
    }

    return false;
}

namespace gc {

static inline AllocKind
GetGCObjectKind(const Class* clasp)
{
    if (clasp == FunctionClassPtr)
        return JSFunction::FinalizeKind;
    uint32_t nslots = JSCLASS_RESERVED_SLOTS(clasp);
    if (clasp->flags & JSCLASS_HAS_PRIVATE)
        nslots++;
    return GetGCObjectKind(nslots);
}

#ifdef JSGC_GENERATIONAL
inline bool
ShouldNurseryAllocate(const Nursery& nursery, AllocKind kind, InitialHeap heap)
{
    return nursery.isEnabled() && IsNurseryAllocable(kind) && heap != TenuredHeap;
}
#endif

inline JSGCTraceKind
GetGCThingTraceKind(const void* thing)
{
    JS_ASSERT(thing);
    const Cell* cell = static_cast<const Cell*>(thing);
#ifdef JSGC_GENERATIONAL
    if (IsInsideNursery(cell->runtimeFromAnyThread(), cell))
        return JSTRACE_OBJECT;
#endif
    return MapAllocToTraceKind(cell->tenuredGetAllocKind());
}

static inline void
GCPoke(JSRuntime* rt)
{
    rt->gcPoke = true;

#ifdef JS_GC_ZEAL
    /* Schedule a GC to happen "soon" after a GC poke. */
    if (rt->gcZeal() == js::gc::ZealPokeValue)
        rt->gcNextScheduled = 1;
#endif
}

class ArenaIter
{
    ArenaHeader* aheader;
    ArenaHeader* remainingHeader;

  public:
    ArenaIter() {
        init();
    }

    ArenaIter(JS::Zone* zone, AllocKind kind) {
        init(zone, kind);
    }

    void init() {
        aheader = nullptr;
        remainingHeader = nullptr;
    }

    void init(ArenaHeader* aheaderArg) {
        aheader = aheaderArg;
        remainingHeader = nullptr;
    }

    void init(JS::Zone* zone, AllocKind kind) {
        aheader = zone->allocator.arenas.getFirstArena(kind);
        remainingHeader = zone->allocator.arenas.getFirstArenaToSweep(kind);
        if (!aheader) {
            aheader = remainingHeader;
            remainingHeader = nullptr;
        }
    }

    bool done() {
        return !aheader;
    }

    ArenaHeader* get() {
        return aheader;
    }

    void next() {
        aheader = aheader->next;
        if (!aheader) {
            aheader = remainingHeader;
            remainingHeader = nullptr;
        }
    }
};

class CellIterImpl
{
    size_t firstThingOffset;
    size_t thingSize;
    ArenaIter aiter;
    FreeSpan firstSpan;
    const FreeSpan* span;
    uintptr_t thing;
    Cell* cell;

  protected:
    CellIterImpl() {
    }

    void initSpan(JS::Zone* zone, AllocKind kind) {
        JS_ASSERT(zone->allocator.arenas.isSynchronizedFreeList(kind));
        firstThingOffset = Arena::firstThingOffset(kind);
        thingSize = Arena::thingSize(kind);
        firstSpan.initAsEmpty();
        span = &firstSpan;
        thing = span->first;
    }

    void init(ArenaHeader* singleAheader) {
        initSpan(singleAheader->zone, singleAheader->getAllocKind());
        aiter.init(singleAheader);
        next();
        aiter.init();
    }

    void init(JS::Zone* zone, AllocKind kind) {
        initSpan(zone, kind);
        aiter.init(zone, kind);
        next();
    }

  public:
    bool done() const {
        return !cell;
    }

    template<typename T> T* get() const {
        JS_ASSERT(!done());
        return static_cast<T*>(cell);
    }

    Cell* getCell() const {
        JS_ASSERT(!done());
        return cell;
    }

    void next() {
        for (;;) {
            if (thing != span->first)
                break;
            if (MOZ_LIKELY(span->hasNext())) {
                thing = span->last + thingSize;
                span = span->nextSpan();
                break;
            }
            if (aiter.done()) {
                cell = nullptr;
                return;
            }
            ArenaHeader* aheader = aiter.get();
            firstSpan = aheader->getFirstFreeSpan();
            span = &firstSpan;
            thing = aheader->arenaAddress() | firstThingOffset;
            aiter.next();
        }
        cell = reinterpret_cast<Cell*>(thing);
        thing += thingSize;
    }
};

class CellIterUnderGC : public CellIterImpl
{
  public:
    CellIterUnderGC(JS::Zone* zone, AllocKind kind) {
#ifdef JSGC_GENERATIONAL
        JS_ASSERT(zone->runtimeFromAnyThread()->gcNursery.isEmpty());
#endif
        JS_ASSERT(zone->runtimeFromAnyThread()->isHeapBusy());
        init(zone, kind);
    }

    CellIterUnderGC(ArenaHeader* aheader) {
        JS_ASSERT(aheader->zone->runtimeFromAnyThread()->isHeapBusy());
        init(aheader);
    }
};

class CellIter : public CellIterImpl
{
    ArenaLists* lists;
    AllocKind kind;
#ifdef DEBUG
    size_t* counter;
#endif
  public:
    CellIter(JS::Zone* zone, AllocKind kind)
      : lists(&zone->allocator.arenas),
        kind(kind)
    {
        /*
         * We have a single-threaded runtime, so there's no need to protect
         * against other threads iterating or allocating. However, we do have
         * background finalization; we have to wait for this to finish if it's
         * currently active.
         */
        if (IsBackgroundFinalized(kind) &&
            zone->allocator.arenas.needBackgroundFinalizeWait(kind))
        {
            gc::FinishBackgroundFinalize(zone->runtimeFromMainThread());
        }

#ifdef JSGC_GENERATIONAL
        /* Evict the nursery before iterating so we can see all things. */
        JSRuntime* rt = zone->runtimeFromMainThread();
        if (!rt->gcNursery.isEmpty())
            MinorGC(rt, JS::gcreason::EVICT_NURSERY);
#endif

        if (lists->isSynchronizedFreeList(kind)) {
            lists = nullptr;
        } else {
            JS_ASSERT(!zone->runtimeFromMainThread()->isHeapBusy());
            lists->copyFreeListToArena(kind);
        }

#ifdef DEBUG
        /* Assert that no GCs can occur while a CellIter is live. */
        counter = &zone->runtimeFromAnyThread()->noGCOrAllocationCheck;
        ++*counter;
#endif

        init(zone, kind);
    }

    ~CellIter() {
#ifdef DEBUG
        JS_ASSERT(*counter > 0);
        --*counter;
#endif
        if (lists)
            lists->clearFreeListInArena(kind);
    }
};

class GCZonesIter
{
  private:
    ZonesIter zone;

  public:
    GCZonesIter(JSRuntime* rt) : zone(rt, WithAtoms) {
        if (!zone->isCollecting())
            next();
    }

    bool done() const { return zone.done(); }

    void next() {
        JS_ASSERT(!done());
        do {
            zone.next();
        } while (!zone.done() && !zone->isCollecting());
    }

    JS::Zone* get() const {
        JS_ASSERT(!done());
        return zone;
    }

    operator JS::Zone*() const { return get(); }
    JS::Zone* operator->() const { return get(); }
};

typedef CompartmentsIterT<GCZonesIter> GCCompartmentsIter;

/* Iterates over all zones in the current zone group. */
class GCZoneGroupIter {
  private:
    JS::Zone* current;

  public:
    GCZoneGroupIter(JSRuntime* rt) {
        JS_ASSERT(rt->isHeapBusy());
        current = rt->gcCurrentZoneGroup;
    }

    bool done() const { return !current; }

    void next() {
        JS_ASSERT(!done());
        current = current->nextNodeInGroup();
    }

    JS::Zone* get() const {
        JS_ASSERT(!done());
        return current;
    }

    operator JS::Zone*() const { return get(); }
    JS::Zone* operator->() const { return get(); }
};

typedef CompartmentsIterT<GCZoneGroupIter> GCCompartmentGroupIter;

#ifdef JSGC_GENERATIONAL
/*
 * Attempt to allocate a new GC thing out of the nursery. If there is not enough
 * room in the nursery or there is an OOM, this method will return nullptr.
 */
template <AllowGC allowGC>
inline JSObject*
TryNewNurseryObject(ThreadSafeContext* cxArg, size_t thingSize, size_t nDynamicSlots)
{
    JSContext* cx = cxArg->asJSContext();

    JS_ASSERT(!IsAtomsCompartment(cx->compartment()));
    JSRuntime* rt = cx->runtime();
    Nursery& nursery = rt->gcNursery;
    JSObject* obj = nursery.allocateObject(cx, thingSize, nDynamicSlots);
    if (obj)
        return obj;
    if (allowGC && !rt->mainThread.suppressGC) {
        MinorGC(cx, JS::gcreason::OUT_OF_NURSERY);

        /* Exceeding gcMaxBytes while tenuring can disable the Nursery. */
        if (nursery.isEnabled()) {
            JSObject* obj = nursery.allocateObject(cx, thingSize, nDynamicSlots);
            JS_ASSERT(obj);
            return obj;
        }
    }
    return nullptr;
}
#endif /* JSGC_GENERATIONAL */

template <AllowGC allowGC>
static inline bool
CheckAllocatorState(ThreadSafeContext* cx, AllocKind kind)
{
    if (!cx->isJSContext())
        return true;

    JSContext* ncx = cx->asJSContext();
    JSRuntime* rt = ncx->runtime();
#if defined(JS_GC_ZEAL) || defined(DEBUG)
    JS_ASSERT_IF(rt->isAtomsCompartment(ncx->compartment()),
                 kind == FINALIZE_STRING ||
                 kind == FINALIZE_SHORT_STRING ||
                 kind == FINALIZE_JITCODE);
    JS_ASSERT(!rt->isHeapBusy());
    JS_ASSERT(!rt->noGCOrAllocationCheck);
#endif

    // For testing out of memory conditions
    JS_OOM_POSSIBLY_FAIL_REPORT(ncx);

    if (allowGC) {
#ifdef JS_GC_ZEAL
        if (rt->needZealousGC())
            js::gc::RunDebugGC(ncx);
#endif

        if (rt->interrupt) {
            // Invoking the interrupt callback can fail and we can't usefully
            // handle that here. Just check in case we need to collect instead.
            js::gc::GCIfNeeded(ncx);
        }

        MaybeCheckStackRoots(ncx);
    }

    return true;
}

template <typename T>
static inline void
CheckIncrementalZoneState(ThreadSafeContext* cx, T* t)
{
#ifdef DEBUG
    if (!cx->isJSContext())
        return;

    Zone* zone = cx->asJSContext()->zone();
    JS_ASSERT_IF(t && zone->wasGCStarted() && (zone->isGCMarking() || zone->isGCSweeping()),
                 t->arenaHeader()->allocatedDuringIncremental);
#endif
}

/*
 * Allocate a new GC thing. After a successful allocation the caller must
 * fully initialize the thing before calling any function that can potentially
 * trigger GC. This will ensure that GC tracing never sees junk values stored
 * in the partially initialized thing.
 */

template <AllowGC allowGC>
inline JSObject*
AllocateObject(ThreadSafeContext* cx, AllocKind kind, size_t nDynamicSlots, InitialHeap heap)
{
    size_t thingSize = Arena::thingSize(kind);

    JS_ASSERT(thingSize == Arena::thingSize(kind));
    if (!CheckAllocatorState<allowGC>(cx, kind))
        return nullptr;

#ifdef JSGC_GENERATIONAL
    if (cx->hasNursery() && ShouldNurseryAllocate(cx->nursery(), kind, heap)) {
        JSObject* obj = TryNewNurseryObject<allowGC>(cx, thingSize, nDynamicSlots);
        if (obj)
            return obj;
    }
#endif

    HeapSlot* slots = nullptr;
    if (nDynamicSlots) {
        slots = cx->pod_malloc<HeapSlot>(nDynamicSlots);
        if (MOZ_UNLIKELY(!slots))
            return nullptr;
        js::Debug_SetSlotRangeToCrashOnTouch(slots, nDynamicSlots);
    }

    JSObject* obj = static_cast<JSObject*>(cx->allocator()->arenas.allocateFromFreeList(kind, thingSize));
    if (!obj)
        obj = static_cast<JSObject*>(js::gc::ArenaLists::refillFreeList<allowGC>(cx, kind));

    if (obj)
        obj->setInitialSlots(slots);
    else
        js_free(slots);

    CheckIncrementalZoneState(cx, obj);
    return obj;
}

template <typename T, AllowGC allowGC>
inline T*
AllocateNonObject(ThreadSafeContext* cx)
{
    AllocKind kind = MapTypeToFinalizeKind<T>::kind;
    size_t thingSize = sizeof(T);

    JS_ASSERT(thingSize == Arena::thingSize(kind));
    if (!CheckAllocatorState<allowGC>(cx, kind))
        return nullptr;

    T* t = static_cast<T*>(cx->allocator()->arenas.allocateFromFreeList(kind, thingSize));
    if (!t)
        t = static_cast<T*>(js::gc::ArenaLists::refillFreeList<allowGC>(cx, kind));

    CheckIncrementalZoneState(cx, t);
    return t;
}

/*
 * When allocating for initialization from a cached object copy, we will
 * potentially destroy the cache entry we want to copy if we allow GC. On the
 * other hand, since these allocations are extremely common, we don't want to
 * delay GC from these allocation sites. Instead we allow the GC, but still
 * fail the allocation, forcing the non-cached path.
 */
template <AllowGC allowGC>
inline JSObject*
AllocateObjectForCacheHit(JSContext* cx, AllocKind kind, InitialHeap heap)
{
#ifdef JSGC_GENERATIONAL
    if (ShouldNurseryAllocate(cx->nursery(), kind, heap)) {
        size_t thingSize = Arena::thingSize(kind);

        JS_ASSERT(thingSize == Arena::thingSize(kind));
        if (!CheckAllocatorState<NoGC>(cx, kind))
            return nullptr;

        JSObject* obj = TryNewNurseryObject<NoGC>(cx, thingSize, 0);
        if (!obj && allowGC) {
            MinorGC(cx, JS::gcreason::OUT_OF_NURSERY);
            return nullptr;
        }
        return obj;
    }
#endif

    JSObject* obj = AllocateObject<NoGC>(cx, kind, 0, heap);
    if (!obj && allowGC) {
        MaybeGC(cx);
        return nullptr;
    }

    return obj;
}

} /* namespace gc */

template <js::AllowGC allowGC>
inline JSObject*
NewGCObject(js::ThreadSafeContext* cx, js::gc::AllocKind kind, size_t nDynamicSlots, js::gc::InitialHeap heap)
{
    JS_ASSERT(kind >= js::gc::FINALIZE_OBJECT0 && kind <= js::gc::FINALIZE_OBJECT_LAST);
    return js::gc::AllocateObject<allowGC>(cx, kind, nDynamicSlots, heap);
}

template <js::AllowGC allowGC>
inline jit::JitCode*
NewJitCode(js::ThreadSafeContext* cx)
{
    return gc::AllocateNonObject<jit::JitCode, allowGC>(cx);
}

inline
types::TypeObject*
NewTypeObject(js::ThreadSafeContext* cx)
{
    return gc::AllocateNonObject<types::TypeObject, js::CanGC>(cx);
}

} /* namespace js */

template <js::AllowGC allowGC>
inline JSString*
js_NewGCString(js::ThreadSafeContext* cx)
{
    return js::gc::AllocateNonObject<JSString, allowGC>(cx);
}

template <js::AllowGC allowGC>
inline JSShortString*
js_NewGCShortString(js::ThreadSafeContext* cx)
{
    return js::gc::AllocateNonObject<JSShortString, allowGC>(cx);
}

inline JSExternalString*
js_NewGCExternalString(js::ThreadSafeContext* cx)
{
    return js::gc::AllocateNonObject<JSExternalString, js::CanGC>(cx);
}

inline JSScript*
js_NewGCScript(js::ThreadSafeContext* cx)
{
    return js::gc::AllocateNonObject<JSScript, js::CanGC>(cx);
}

inline js::LazyScript*
js_NewGCLazyScript(js::ThreadSafeContext* cx)
{
    return js::gc::AllocateNonObject<js::LazyScript, js::CanGC>(cx);
}

inline js::Shape*
js_NewGCShape(js::ThreadSafeContext* cx)
{
    return js::gc::AllocateNonObject<js::Shape, js::CanGC>(cx);
}

template <js::AllowGC allowGC>
inline js::BaseShape*
js_NewGCBaseShape(js::ThreadSafeContext* cx)
{
    return js::gc::AllocateNonObject<js::BaseShape, allowGC>(cx);
}

#endif /* jsgcinlines_h */