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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 vm_ObjectGroup_h
#define vm_ObjectGroup_h
#include "js/shadow/ObjectGroup.h" // JS::shadow::ObjectGroup
#include "jsfriendapi.h"
#include "ds/IdValuePair.h"
#include "gc/Allocator.h"
#include "gc/Barrier.h"
#include "gc/GCProbes.h"
#include "js/CharacterEncoding.h"
#include "js/GCHashTable.h"
#include "js/TypeDecls.h"
#include "js/UbiNode.h"
#include "vm/TaggedProto.h"
namespace js {
class TypeDescr;
class ObjectGroupRealm;
class PlainObject;
/*
* The NewObjectKind allows an allocation site to specify the lifetime
* requirements that must be fixed at allocation time.
*/
enum NewObjectKind {
/* This is the default. Most objects are generic. */
GenericObject,
/*
* Objects which will not benefit from being allocated in the nursery
* (e.g. because they are known to have a long lifetime) may be allocated
* with this kind to place them immediately into the tenured generation.
*/
TenuredObject
};
class ObjectGroup : public gc::TenuredCellWithNonGCPointer<const JSClass> {
public:
/* Class shared by objects in this group, stored in the cell header. */
const JSClass* clasp() const { return headerPtr(); }
private:
/* Prototype shared by objects in this group. */
GCPtr<TaggedProto> proto_; // set by constructor
/* Realm shared by objects in this group. */
JS::Realm* realm_; // set by constructor
// Non-null only for typed objects.
GCPtr<TypeDescr*> typeDescr_; // set by constructor
// END OF PROPERTIES
private:
static inline uint32_t offsetOfClasp() { return offsetOfHeaderPtr(); }
static inline uint32_t offsetOfProto() {
return offsetof(ObjectGroup, proto_);
}
static inline uint32_t offsetOfRealm() {
return offsetof(ObjectGroup, realm_);
}
friend class gc::GCRuntime;
// See JSObject::offsetOfGroup() comment.
friend class js::jit::MacroAssembler;
public:
inline ObjectGroup(const JSClass* clasp, TaggedProto proto, JS::Realm* realm,
TypeDescr* descr);
const GCPtr<TaggedProto>& proto() const { return proto_; }
GCPtr<TaggedProto>& proto() { return proto_; }
void setProtoUnchecked(TaggedProto proto);
JS::Compartment* compartment() const {
return JS::GetCompartmentForRealm(realm_);
}
JS::Compartment* maybeCompartment() const { return compartment(); }
JS::Realm* realm() const { return realm_; }
TypeDescr* maybeTypeDescr() {
// Note: there is no need to sweep when accessing the type descriptor
// of an object, as it is strongly held and immutable.
return typeDescr_;
}
TypeDescr& typeDescr() {
MOZ_ASSERT(typeDescr_);
return *typeDescr_;
}
/* Helpers */
void traceChildren(JSTracer* trc);
void finalize(JSFreeOp* fop) {
// Nothing to do.
}
static const JS::TraceKind TraceKind = JS::TraceKind::ObjectGroup;
static void staticAsserts() {
static_assert(offsetof(ObjectGroup, proto_) ==
offsetof(JS::shadow::ObjectGroup, proto));
}
static ObjectGroup* defaultNewGroup(JSContext* cx, const JSClass* clasp,
TaggedProto proto,
Handle<TypeDescr*> descr = nullptr);
};
// Structure used to manage the groups in a realm.
class ObjectGroupRealm {
private:
class NewTable;
private:
// Set of default 'new' groups in the realm.
NewTable* defaultNewTable = nullptr;
// This cache is purged on GC.
class DefaultNewGroupCache {
ObjectGroup* group_;
TypeDescr* associated_;
public:
DefaultNewGroupCache() : associated_(nullptr) { purge(); }
void purge() { group_ = nullptr; }
void put(ObjectGroup* group, TypeDescr* associated) {
group_ = group;
associated_ = associated;
}
MOZ_ALWAYS_INLINE ObjectGroup* lookup(const JSClass* clasp,
TaggedProto proto,
TypeDescr* associated);
} defaultNewGroupCache = {};
// END OF PROPERTIES
private:
friend class ObjectGroup;
public:
struct NewEntry;
ObjectGroupRealm() = default;
~ObjectGroupRealm();
ObjectGroupRealm(ObjectGroupRealm&) = delete;
void operator=(ObjectGroupRealm&) = delete;
static ObjectGroupRealm& getForNewObject(JSContext* cx);
void addSizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf,
size_t* realmTables);
void clearTables();
void purge() { defaultNewGroupCache.purge(); }
#ifdef JSGC_HASH_TABLE_CHECKS
void checkTablesAfterMovingGC() {
checkNewTableAfterMovingGC(defaultNewTable);
}
#endif
void fixupTablesAfterMovingGC() {
fixupNewTableAfterMovingGC(defaultNewTable);
}
private:
#ifdef JSGC_HASH_TABLE_CHECKS
void checkNewTableAfterMovingGC(NewTable* table);
#endif
void fixupNewTableAfterMovingGC(NewTable* table);
};
PlainObject* NewPlainObjectWithProperties(JSContext* cx,
IdValuePair* properties,
size_t nproperties,
NewObjectKind newKind);
} // namespace js
// JS::ubi::Nodes can point to object groups; they're js::gc::Cell instances
// with no associated compartment.
namespace JS {
namespace ubi {
template <>
class Concrete<js::ObjectGroup> : TracerConcrete<js::ObjectGroup> {
protected:
explicit Concrete(js::ObjectGroup* ptr)
: TracerConcrete<js::ObjectGroup>(ptr) {}
public:
static void construct(void* storage, js::ObjectGroup* ptr) {
new (storage) Concrete(ptr);
}
Size size(mozilla::MallocSizeOf mallocSizeOf) const override;
const char16_t* typeName() const override { return concreteTypeName; }
static const char16_t concreteTypeName[];
};
} // namespace ubi
} // namespace JS
#endif /* vm_ObjectGroup_h */
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