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diff --git a/js/src/jsgcinlines.h b/js/src/jsgcinlines.h
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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 "mozilla/DebugOnly.h"
+#include "mozilla/Maybe.h"
+
+#include "gc/GCTrace.h"
+#include "gc/Zone.h"
+
+namespace js {
+namespace gc {
+
+inline void
+MakeAccessibleAfterMovingGC(void* anyp) {}
+
+inline void
+MakeAccessibleAfterMovingGC(JSObject* obj) {
+ if (obj->isNative())
+ obj->as<NativeObject>().updateShapeAfterMovingGC();
+}
+
+static inline AllocKind
+GetGCObjectKind(const Class* clasp)
+{
+ if (clasp == FunctionClassPtr)
+ return AllocKind::FUNCTION;
+ uint32_t nslots = JSCLASS_RESERVED_SLOTS(clasp);
+ if (clasp->flags & JSCLASS_HAS_PRIVATE)
+ nslots++;
+ return GetGCObjectKind(nslots);
+}
+
+inline void
+GCRuntime::poke()
+{
+ poked = true;
+
+#ifdef JS_GC_ZEAL
+ /* Schedule a GC to happen "soon" after a GC poke. */
+ if (hasZealMode(ZealMode::Poke))
+ nextScheduled = 1;
+#endif
+}
+
+class ArenaIter
+{
+ Arena* arena;
+ Arena* unsweptArena;
+ Arena* sweptArena;
+ mozilla::DebugOnly<bool> initialized;
+
+ public:
+ ArenaIter()
+ : arena(nullptr), unsweptArena(nullptr), sweptArena(nullptr), initialized(false) {}
+
+ ArenaIter(JS::Zone* zone, AllocKind kind) : initialized(false) { init(zone, kind); }
+
+ void init(JS::Zone* zone, AllocKind kind) {
+ MOZ_ASSERT(!initialized);
+ MOZ_ASSERT(zone);
+ initialized = true;
+ arena = zone->arenas.getFirstArena(kind);
+ unsweptArena = zone->arenas.getFirstArenaToSweep(kind);
+ sweptArena = zone->arenas.getFirstSweptArena(kind);
+ if (!unsweptArena) {
+ unsweptArena = sweptArena;
+ sweptArena = nullptr;
+ }
+ if (!arena) {
+ arena = unsweptArena;
+ unsweptArena = sweptArena;
+ sweptArena = nullptr;
+ }
+ }
+
+ bool done() const {
+ MOZ_ASSERT(initialized);
+ return !arena;
+ }
+
+ Arena* get() const {
+ MOZ_ASSERT(!done());
+ return arena;
+ }
+
+ void next() {
+ MOZ_ASSERT(!done());
+ arena = arena->next;
+ if (!arena) {
+ arena = unsweptArena;
+ unsweptArena = sweptArena;
+ sweptArena = nullptr;
+ }
+ }
+};
+
+enum CellIterNeedsBarrier : uint8_t
+{
+ CellIterDoesntNeedBarrier = 0,
+ CellIterMayNeedBarrier = 1
+};
+
+class ArenaCellIterImpl
+{
+ size_t firstThingOffset;
+ size_t thingSize;
+ Arena* arenaAddr;
+ FreeSpan span;
+ uint_fast16_t thing;
+ JS::TraceKind traceKind;
+ bool needsBarrier;
+ mozilla::DebugOnly<bool> initialized;
+
+ // Upon entry, |thing| points to any thing (free or used) and finds the
+ // first used thing, which may be |thing|.
+ void moveForwardIfFree() {
+ MOZ_ASSERT(!done());
+ MOZ_ASSERT(thing);
+ // Note: if |span| is empty, this test will fail, which is what we want
+ // -- |span| being empty means that we're past the end of the last free
+ // thing, all the remaining things in the arena are used, and we'll
+ // never need to move forward.
+ if (thing == span.first) {
+ thing = span.last + thingSize;
+ span = *span.nextSpan(arenaAddr);
+ }
+ }
+
+ public:
+ ArenaCellIterImpl()
+ : firstThingOffset(0),
+ thingSize(0),
+ arenaAddr(nullptr),
+ thing(0),
+ traceKind(JS::TraceKind::Null),
+ needsBarrier(false),
+ initialized(false)
+ {}
+
+ explicit ArenaCellIterImpl(Arena* arena, CellIterNeedsBarrier mayNeedBarrier)
+ : initialized(false)
+ {
+ init(arena, mayNeedBarrier);
+ }
+
+ void init(Arena* arena, CellIterNeedsBarrier mayNeedBarrier) {
+ MOZ_ASSERT(!initialized);
+ MOZ_ASSERT(arena);
+ MOZ_ASSERT_IF(!mayNeedBarrier,
+ CurrentThreadIsPerformingGC() || CurrentThreadIsGCSweeping());
+ initialized = true;
+ AllocKind kind = arena->getAllocKind();
+ firstThingOffset = Arena::firstThingOffset(kind);
+ thingSize = Arena::thingSize(kind);
+ traceKind = MapAllocToTraceKind(kind);
+ needsBarrier = mayNeedBarrier && !arena->zone->runtimeFromMainThread()->isHeapCollecting();
+ reset(arena);
+ }
+
+ // Use this to move from an Arena of a particular kind to another Arena of
+ // the same kind.
+ void reset(Arena* arena) {
+ MOZ_ASSERT(initialized);
+ MOZ_ASSERT(arena);
+ arenaAddr = arena;
+ span = *arena->getFirstFreeSpan();
+ thing = firstThingOffset;
+ moveForwardIfFree();
+ }
+
+ bool done() const {
+ MOZ_ASSERT(initialized);
+ MOZ_ASSERT(thing <= ArenaSize);
+ return thing == ArenaSize;
+ }
+
+ TenuredCell* getCell() const {
+ MOZ_ASSERT(!done());
+ TenuredCell* cell = reinterpret_cast<TenuredCell*>(uintptr_t(arenaAddr) + thing);
+
+ // This can result in a a new reference being created to an object that
+ // an ongoing incremental GC may find to be unreachable, so we may need
+ // a barrier here.
+ if (needsBarrier)
+ ExposeGCThingToActiveJS(JS::GCCellPtr(cell, traceKind));
+
+ return cell;
+ }
+
+ template<typename T> T* get() const {
+ MOZ_ASSERT(!done());
+ MOZ_ASSERT(JS::MapTypeToTraceKind<T>::kind == traceKind);
+ return static_cast<T*>(getCell());
+ }
+
+ void next() {
+ MOZ_ASSERT(!done());
+ thing += thingSize;
+ if (thing < ArenaSize)
+ moveForwardIfFree();
+ }
+};
+
+template<>
+JSObject*
+ArenaCellIterImpl::get<JSObject>() const;
+
+class ArenaCellIter : public ArenaCellIterImpl
+{
+ public:
+ explicit ArenaCellIter(Arena* arena)
+ : ArenaCellIterImpl(arena, CellIterMayNeedBarrier)
+ {
+ MOZ_ASSERT(arena->zone->runtimeFromMainThread()->isHeapTracing());
+ }
+};
+
+class ArenaCellIterUnderGC : public ArenaCellIterImpl
+{
+ public:
+ explicit ArenaCellIterUnderGC(Arena* arena)
+ : ArenaCellIterImpl(arena, CellIterDoesntNeedBarrier)
+ {
+ MOZ_ASSERT(CurrentThreadIsPerformingGC());
+ }
+};
+
+class ArenaCellIterUnderFinalize : public ArenaCellIterImpl
+{
+ public:
+ explicit ArenaCellIterUnderFinalize(Arena* arena)
+ : ArenaCellIterImpl(arena, CellIterDoesntNeedBarrier)
+ {
+ MOZ_ASSERT(CurrentThreadIsGCSweeping());
+ }
+};
+
+template <typename T>
+class ZoneCellIter;
+
+template <>
+class ZoneCellIter<TenuredCell> {
+ ArenaIter arenaIter;
+ ArenaCellIterImpl cellIter;
+ mozilla::Maybe<JS::AutoAssertNoGC> nogc;
+
+ protected:
+ // For use when a subclass wants to insert some setup before init().
+ ZoneCellIter() {}
+
+ void init(JS::Zone* zone, AllocKind kind) {
+ MOZ_ASSERT_IF(IsNurseryAllocable(kind),
+ zone->runtimeFromAnyThread()->gc.nursery.isEmpty());
+ initForTenuredIteration(zone, kind);
+ }
+
+ void initForTenuredIteration(JS::Zone* zone, AllocKind kind) {
+ JSRuntime* rt = zone->runtimeFromAnyThread();
+
+ // If called from outside a GC, ensure that the heap is in a state
+ // that allows us to iterate.
+ if (!rt->isHeapBusy()) {
+ // Assert that no GCs can occur while a ZoneCellIter is live.
+ nogc.emplace(rt);
+ }
+
+ // 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 may have to wait for this to finish if
+ // it's currently active.
+ if (IsBackgroundFinalized(kind) && zone->arenas.needBackgroundFinalizeWait(kind))
+ rt->gc.waitBackgroundSweepEnd();
+ arenaIter.init(zone, kind);
+ if (!arenaIter.done())
+ cellIter.init(arenaIter.get(), CellIterMayNeedBarrier);
+ }
+
+ public:
+ ZoneCellIter(JS::Zone* zone, AllocKind kind) {
+ // If we are iterating a nursery-allocated kind then we need to
+ // evict first so that we can see all things.
+ if (IsNurseryAllocable(kind)) {
+ JSRuntime* rt = zone->runtimeFromMainThread();
+ rt->gc.evictNursery();
+ }
+
+ init(zone, kind);
+ }
+
+ ZoneCellIter(JS::Zone* zone, AllocKind kind, const js::gc::AutoAssertEmptyNursery&) {
+ // No need to evict the nursery. (This constructor is known statically
+ // to not GC.)
+ init(zone, kind);
+ }
+
+ bool done() const {
+ return arenaIter.done();
+ }
+
+ template<typename T>
+ T* get() const {
+ MOZ_ASSERT(!done());
+ return cellIter.get<T>();
+ }
+
+ TenuredCell* getCell() const {
+ MOZ_ASSERT(!done());
+ return cellIter.getCell();
+ }
+
+ void next() {
+ MOZ_ASSERT(!done());
+ cellIter.next();
+ if (cellIter.done()) {
+ MOZ_ASSERT(!arenaIter.done());
+ arenaIter.next();
+ if (!arenaIter.done())
+ cellIter.reset(arenaIter.get());
+ }
+ }
+};
+
+// Iterator over the cells in a Zone, where the GC type (JSString, JSObject) is
+// known, for a single AllocKind. Example usages:
+//
+// for (auto obj = zone->cellIter<JSObject>(AllocKind::OBJECT0); !obj.done(); obj.next())
+// ...
+//
+// for (auto script = zone->cellIter<JSScript>(); !script.done(); script.next())
+// f(script->code());
+//
+// As this code demonstrates, you can use 'script' as if it were a JSScript*.
+// Its actual type is ZoneCellIter<JSScript>, but for most purposes it will
+// autoconvert to JSScript*.
+//
+// Note that in the JSScript case, ZoneCellIter is able to infer the AllocKind
+// from the type 'JSScript', whereas in the JSObject case, the kind must be
+// given (because there are multiple AllocKinds for objects).
+//
+// Also, the static rooting hazard analysis knows that the JSScript case will
+// not GC during construction. The JSObject case needs to GC, or more precisely
+// to empty the nursery and clear out the store buffer, so that it can see all
+// objects to iterate over (the nursery is not iterable) and remove the
+// possibility of having pointers from the store buffer to data hanging off
+// stuff we're iterating over that we are going to delete. (The latter should
+// not be a problem, since such instances should be using RelocatablePtr do
+// remove themselves from the store buffer on deletion, but currently for
+// subtle reasons that isn't good enough.)
+//
+// If the iterator is used within a GC, then there is no need to evict the
+// nursery (again). You may select a variant that will skip the eviction either
+// by specializing on a GCType that is never allocated in the nursery, or
+// explicitly by passing in a trailing AutoAssertEmptyNursery argument.
+//
+template <typename GCType>
+class ZoneCellIter : public ZoneCellIter<TenuredCell> {
+ public:
+ // Non-nursery allocated (equivalent to having an entry in
+ // MapTypeToFinalizeKind). The template declaration here is to discard this
+ // constructor overload if MapTypeToFinalizeKind<GCType>::kind does not
+ // exist. Note that there will be no remaining overloads that will work,
+ // which makes sense given that you haven't specified which of the
+ // AllocKinds to use for GCType.
+ //
+ // If we later add a nursery allocable GCType with a single AllocKind, we
+ // will want to add an overload of this constructor that does the right
+ // thing (ie, it empties the nursery before iterating.)
+ explicit ZoneCellIter(JS::Zone* zone) : ZoneCellIter<TenuredCell>() {
+ init(zone, MapTypeToFinalizeKind<GCType>::kind);
+ }
+
+ // Non-nursery allocated, nursery is known to be empty: same behavior as above.
+ ZoneCellIter(JS::Zone* zone, const js::gc::AutoAssertEmptyNursery&) : ZoneCellIter(zone) {
+ }
+
+ // Arbitrary kind, which will be assumed to be nursery allocable (and
+ // therefore the nursery will be emptied before iterating.)
+ ZoneCellIter(JS::Zone* zone, AllocKind kind) : ZoneCellIter<TenuredCell>(zone, kind) {
+ }
+
+ // Arbitrary kind, which will be assumed to be nursery allocable, but the
+ // nursery is known to be empty already: same behavior as non-nursery types.
+ ZoneCellIter(JS::Zone* zone, AllocKind kind, const js::gc::AutoAssertEmptyNursery& empty)
+ : ZoneCellIter<TenuredCell>(zone, kind, empty)
+ {
+ }
+
+ GCType* get() const { return ZoneCellIter<TenuredCell>::get<GCType>(); }
+ operator GCType*() const { return get(); }
+ GCType* operator ->() const { return get(); }
+};
+
+class GrayObjectIter : public ZoneCellIter<TenuredCell> {
+ public:
+ explicit GrayObjectIter(JS::Zone* zone, AllocKind kind) : ZoneCellIter<TenuredCell>() {
+ initForTenuredIteration(zone, kind);
+ }
+
+ JSObject* get() const { return ZoneCellIter<TenuredCell>::get<JSObject>(); }
+ operator JSObject*() const { return get(); }
+ JSObject* operator ->() const { return get(); }
+};
+
+class GCZonesIter
+{
+ private:
+ ZonesIter zone;
+
+ public:
+ explicit GCZonesIter(JSRuntime* rt, ZoneSelector selector = WithAtoms) : zone(rt, selector) {
+ MOZ_ASSERT(CurrentThreadCanAccessRuntime(rt) && rt->isHeapBusy());
+ if (!zone->isCollecting())
+ next();
+ }
+
+ bool done() const { return zone.done(); }
+
+ void next() {
+ MOZ_ASSERT(!done());
+ do {
+ zone.next();
+ } while (!zone.done() && !zone->isCollectingFromAnyThread());
+ }
+
+ JS::Zone* get() const {
+ MOZ_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:
+ explicit GCZoneGroupIter(JSRuntime* rt) {
+ MOZ_ASSERT(CurrentThreadIsPerformingGC());
+ current = rt->gc.getCurrentZoneGroup();
+ }
+
+ bool done() const { return !current; }
+
+ void next() {
+ MOZ_ASSERT(!done());
+ current = current->nextNodeInGroup();
+ }
+
+ JS::Zone* get() const {
+ MOZ_ASSERT(!done());
+ return current;
+ }
+
+ operator JS::Zone*() const { return get(); }
+ JS::Zone* operator->() const { return get(); }
+};
+
+typedef CompartmentsIterT<GCZoneGroupIter> GCCompartmentGroupIter;
+
+inline void
+RelocationOverlay::forwardTo(Cell* cell)
+{
+ MOZ_ASSERT(!isForwarded());
+ // The location of magic_ is important because it must never be valid to see
+ // the value Relocated there in a GC thing that has not been moved.
+ static_assert(offsetof(RelocationOverlay, magic_) == offsetof(JSObject, group_) &&
+ offsetof(RelocationOverlay, magic_) == offsetof(js::Shape, base_) &&
+ offsetof(RelocationOverlay, magic_) == offsetof(JSString, d.u1.flags),
+ "RelocationOverlay::magic_ is in the wrong location");
+ magic_ = Relocated;
+ newLocation_ = cell;
+}
+
+} /* namespace gc */
+} /* namespace js */
+
+#endif /* jsgcinlines_h */
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