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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* 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/. */
#include "vm/ReceiverGuard.h"
#include "builtin/TypedObject.h"
#include "vm/UnboxedObject.h"
#include "jsobjinlines.h"
using namespace js;
ReceiverGuard::ReceiverGuard(JSObject* obj)
: group(nullptr), shape(nullptr)
{
if (obj) {
if (obj->is<UnboxedPlainObject>()) {
group = obj->group();
if (UnboxedExpandoObject* expando = obj->as<UnboxedPlainObject>().maybeExpando())
shape = expando->lastProperty();
} else if (obj->is<UnboxedArrayObject>() || obj->is<TypedObject>()) {
group = obj->group();
} else {
shape = obj->maybeShape();
}
}
}
ReceiverGuard::ReceiverGuard(ObjectGroup* group, Shape* shape)
: group(group), shape(shape)
{
if (group) {
const Class* clasp = group->clasp();
if (clasp == &UnboxedPlainObject::class_) {
// Keep both group and shape.
} else if (clasp == &UnboxedArrayObject::class_ || IsTypedObjectClass(clasp)) {
this->shape = nullptr;
} else {
this->group = nullptr;
}
}
}
/* static */ int32_t
HeapReceiverGuard::keyBits(JSObject* obj)
{
if (obj->is<UnboxedPlainObject>()) {
// Both the group and shape need to be guarded for unboxed plain objects.
return obj->as<UnboxedPlainObject>().maybeExpando() ? 0 : 1;
}
if (obj->is<UnboxedArrayObject>() || obj->is<TypedObject>()) {
// Only the group needs to be guarded for unboxed arrays and typed objects.
return 2;
}
// Other objects only need the shape to be guarded.
return 3;
}
void
HeapReceiverGuard::trace(JSTracer* trc)
{
TraceNullableEdge(trc, &shape_, "receiver_guard_shape");
TraceNullableEdge(trc, &group_, "receiver_guard_group");
}
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