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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* 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 gc_StableCellHasher_inl_h
#define gc_StableCellHasher_inl_h
#include "gc/StableCellHasher.h"
#include "mozilla/HashFunctions.h"
#include "gc/Cell.h"
#include "gc/Marking.h"
#include "gc/Zone.h"
#include "vm/JSObject.h"
#include "vm/NativeObject.h"
#include "vm/Runtime.h"
namespace js {
namespace gc {
extern uint64_t NextCellUniqueId(JSRuntime* rt);
inline bool MaybeGetUniqueId(Cell* cell, uint64_t* uidp) {
MOZ_ASSERT(uidp);
MOZ_ASSERT(CurrentThreadCanAccessRuntime(cell->runtimeFromAnyThread()) ||
CurrentThreadIsPerformingGC());
if (cell->is<JSObject>()) {
JSObject* obj = cell->as<JSObject>();
if (obj->is<NativeObject>()) {
auto* nobj = &obj->as<NativeObject>();
if (!nobj->hasUniqueId()) {
return false;
}
*uidp = nobj->uniqueId();
return true;
}
}
// Get an existing uid, if one has been set.
auto p = cell->zone()->uniqueIds().readonlyThreadsafeLookup(cell);
if (!p) {
return false;
}
*uidp = p->value();
return true;
}
extern bool CreateUniqueIdForNativeObject(NativeObject* obj, uint64_t* uidp);
extern bool CreateUniqueIdForNonNativeObject(Cell* cell, UniqueIdMap::AddPtr,
uint64_t* uidp);
inline bool GetOrCreateUniqueId(Cell* cell, uint64_t* uidp) {
MOZ_ASSERT(uidp);
MOZ_ASSERT(CurrentThreadCanAccessRuntime(cell->runtimeFromAnyThread()) ||
CurrentThreadIsPerformingGC());
if (cell->is<JSObject>()) {
JSObject* obj = cell->as<JSObject>();
if (obj->is<NativeObject>()) {
auto* nobj = &obj->as<NativeObject>();
if (nobj->hasUniqueId()) {
*uidp = nobj->uniqueId();
return true;
}
return CreateUniqueIdForNativeObject(nobj, uidp);
}
}
// Get an existing uid, if one has been set.
auto p = cell->zone()->uniqueIds().lookupForAdd(cell);
if (p) {
*uidp = p->value();
return true;
}
return CreateUniqueIdForNonNativeObject(cell, p, uidp);
}
inline bool SetOrUpdateUniqueId(JSContext* cx, Cell* cell, uint64_t uid) {
MOZ_ASSERT(CurrentThreadCanAccessRuntime(cell->runtimeFromAnyThread()));
if (cell->is<JSObject>()) {
JSObject* obj = cell->as<JSObject>();
if (obj->is<NativeObject>()) {
auto* nobj = &obj->as<NativeObject>();
return nobj->setOrUpdateUniqueId(cx, uid);
}
}
// If the cell was in the nursery, hopefully unlikely, then we need to
// tell the nursery about it so that it can sweep the uid if the thing
// does not get tenured.
JSRuntime* runtime = cell->runtimeFromMainThread();
if (IsInsideNursery(cell) &&
!runtime->gc.nursery().addedUniqueIdToCell(cell)) {
return false;
}
return cell->zone()->uniqueIds().put(cell, uid);
}
inline uint64_t GetUniqueIdInfallible(Cell* cell) {
uint64_t uid;
AutoEnterOOMUnsafeRegion oomUnsafe;
if (!GetOrCreateUniqueId(cell, &uid)) {
oomUnsafe.crash("failed to allocate uid");
}
return uid;
}
inline bool HasUniqueId(Cell* cell) {
MOZ_ASSERT(CurrentThreadCanAccessRuntime(cell->runtimeFromAnyThread()) ||
CurrentThreadIsPerformingGC());
if (cell->is<JSObject>()) {
JSObject* obj = cell->as<JSObject>();
if (obj->is<NativeObject>()) {
return obj->as<NativeObject>().hasUniqueId();
}
}
return cell->zone()->uniqueIds().has(cell);
}
inline void TransferUniqueId(Cell* tgt, Cell* src) {
MOZ_ASSERT(src != tgt);
MOZ_ASSERT(CurrentThreadCanAccessRuntime(tgt->runtimeFromAnyThread()));
MOZ_ASSERT(src->zone() == tgt->zone());
Zone* zone = tgt->zone();
MOZ_ASSERT_IF(zone->uniqueIds().has(src), !zone->uniqueIds().has(tgt));
zone->uniqueIds().rekeyIfMoved(src, tgt);
}
inline void RemoveUniqueId(Cell* cell) {
MOZ_ASSERT(CurrentThreadCanAccessRuntime(cell->runtimeFromAnyThread()));
// The cell may no longer be in the hash table if it was swapped with a
// NativeObject.
cell->zone()->uniqueIds().remove(cell);
}
} // namespace gc
static inline js::HashNumber UniqueIdToHash(uint64_t uid) {
// This uses the default hasher which returns the lower 32 bits of 64 bit
// integers as the hash code. This is OK because he result will be scrambled
// later by ScrambleHashCode().
return DefaultHasher<uint64_t>::hash(uid);
}
template <typename T>
/* static */ bool StableCellHasher<T>::maybeGetHash(const Lookup& l,
HashNumber* hashOut) {
if (!l) {
*hashOut = 0;
return true;
}
uint64_t uid;
if (!gc::MaybeGetUniqueId(l, &uid)) {
return false;
}
*hashOut = UniqueIdToHash(uid);
return true;
}
template <typename T>
/* static */ bool StableCellHasher<T>::ensureHash(const Lookup& l,
HashNumber* hashOut) {
if (!l) {
*hashOut = 0;
return true;
}
uint64_t uid;
if (!gc::GetOrCreateUniqueId(l, &uid)) {
return false;
}
*hashOut = UniqueIdToHash(uid);
return true;
}
template <typename T>
/* static */ HashNumber StableCellHasher<T>::hash(const Lookup& l) {
if (!l) {
return 0;
}
// We have to access the zone from-any-thread here: a worker thread may be
// cloning a self-hosted object from the main runtime's self- hosting zone
// into another runtime. The zone's uid lock will protect against multiple
// workers doing this simultaneously.
MOZ_ASSERT(CurrentThreadCanAccessZone(l->zoneFromAnyThread()) ||
CurrentThreadIsPerformingGC());
return UniqueIdToHash(gc::GetUniqueIdInfallible(l));
}
template <typename T>
/* static */ bool StableCellHasher<T>::match(const Key& k, const Lookup& l) {
if (k == l) {
return true;
}
if (!k || !l) {
return false;
}
MOZ_ASSERT(CurrentThreadCanAccessZone(l->zoneFromAnyThread()) ||
CurrentThreadIsPerformingGC());
#ifdef DEBUG
// Incremental table sweeping means that existing table entries may no
// longer have unique IDs. We fail the match in that case and the entry is
// removed from the table later on.
if (!gc::HasUniqueId(k)) {
Key key = k;
MOZ_ASSERT(key->zoneFromAnyThread()->needsIncrementalBarrier() &&
!key->isMarkedAny());
}
MOZ_ASSERT(gc::HasUniqueId(l));
#endif
uint64_t keyId;
if (!gc::MaybeGetUniqueId(k, &keyId)) {
// Key is dead and cannot match lookup which must be live.
return false;
}
return keyId == gc::GetUniqueIdInfallible(l);
}
} // namespace js
#endif // gc_StableCellHasher_inl_h
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