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-rw-r--r--js/src/gc/StableCellHasher-inl.h245
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diff --git a/js/src/gc/StableCellHasher-inl.h b/js/src/gc/StableCellHasher-inl.h
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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(!IsInsideNursery(tgt));
+ MOZ_ASSERT(CurrentThreadCanAccessRuntime(tgt->runtimeFromAnyThread()));
+ MOZ_ASSERT(src->zone() == tgt->zone());
+
+ Zone* zone = tgt->zone();
+ MOZ_ASSERT(!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(IsAboutToBeFinalizedUnbarriered(key));
+ }
+ 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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