Source code
Revision control
Copy as Markdown
Other Tools
/* -*- 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
#include "vm/RealmFuses.h"
#include "vm/GlobalObject.h"
#include "vm/NativeObject.h"
#include "vm/ObjectOperations.h"
#include "vm/Realm.h"
#include "vm/SelfHosting.h"
void js::InvalidatingRealmFuse::popFuse(JSContext* cx, RealmFuses& realmFuses) {
InvalidatingFuse::popFuse(cx);
for (auto& fd : realmFuses.fuseDependencies) {
fd.invalidateForFuse(cx, this);
}
}
bool js::InvalidatingRealmFuse::addFuseDependency(JSContext* cx,
Handle<JSScript*> script) {
MOZ_ASSERT(script->realm() == cx->realm());
auto* dss =
cx->realm()->realmFuses.fuseDependencies.getOrCreateDependentScriptSet(
cx, this);
if (!dss) {
return false;
}
return dss->addScriptForFuse(this, script);
}
void js::PopsOptimizedGetIteratorFuse::popFuse(JSContext* cx,
RealmFuses& realmFuses) {
// Pop Self.
RealmFuse::popFuse(cx);
// Pop associated fuse in same realm as current object.
realmFuses.optimizeGetIteratorFuse.popFuse(cx, realmFuses);
}
int32_t js::RealmFuses::fuseOffsets[uint8_t(
RealmFuses::FuseIndex::LastFuseIndex)] = {
#define FUSE(Name, LowerName) offsetof(RealmFuses, LowerName),
FOR_EACH_REALM_FUSE(FUSE)
#undef FUSE
};
// static
int32_t js::RealmFuses::offsetOfFuseWordRelativeToRealm(
RealmFuses::FuseIndex index) {
int32_t base_offset = offsetof(Realm, realmFuses);
int32_t fuse_offset = RealmFuses::fuseOffsets[uint8_t(index)];
int32_t fuseWordOffset = GuardFuse::fuseOffset();
return base_offset + fuse_offset + fuseWordOffset;
}
const char* js::RealmFuses::fuseNames[] = {
#define FUSE(Name, LowerName) #LowerName,
FOR_EACH_REALM_FUSE(FUSE)
#undef FUSE
};
// TODO: It is not elegant that we have both this mechanism, but also
// GuardFuse::name, and all the overrides for naming fuses. The issue is
// that this method is static to handle consumers that don't have a
// RealmFuses around but work with indexes (e.g. spew code).
//
// I'd love it if we had a better answer.
const char* js::RealmFuses::getFuseName(RealmFuses::FuseIndex index) {
uint8_t rawIndex = uint8_t(index);
MOZ_ASSERT(rawIndex > 0 && index < RealmFuses::FuseIndex::LastFuseIndex);
return fuseNames[rawIndex];
}
bool js::OptimizeGetIteratorFuse::checkInvariant(JSContext* cx) {
// Simple invariant: this fuse merely reflects the conjunction of a group of
// fuses, so if this fuse is intact, then the invariant it asserts is that
// these two realm fuses are also intact.
auto& realmFuses = cx->realm()->realmFuses;
return realmFuses.arrayPrototypeIteratorFuse.intact() &&
realmFuses.arrayPrototypeIteratorNextFuse.intact() &&
realmFuses.arrayIteratorPrototypeHasNoReturnProperty.intact() &&
realmFuses.iteratorPrototypeHasNoReturnProperty.intact() &&
realmFuses.arrayIteratorPrototypeHasIteratorProto.intact() &&
realmFuses.iteratorPrototypeHasObjectProto.intact() &&
realmFuses.objectPrototypeHasNoReturnProperty.intact();
}
bool js::ArrayPrototypeIteratorFuse::checkInvariant(JSContext* cx) {
// Prototype must be Array.prototype.
auto* proto = cx->global()->maybeGetArrayPrototype();
if (!proto) {
// No proto, invariant still holds
return true;
}
PropertyKey iteratorKey =
PropertyKey::Symbol(cx->wellKnownSymbols().iterator);
// Ensure that Array.prototype's @@iterator slot is unchanged.
mozilla::Maybe<PropertyInfo> prop = proto->lookupPure(iteratorKey);
if (prop.isNothing() || !prop->isDataProperty()) {
return false;
}
auto slot = prop->slot();
const Value& iterVal = proto->getSlot(slot);
if (!iterVal.isObject() || !iterVal.toObject().is<JSFunction>()) {
return false;
}
auto* iterFun = &iterVal.toObject().as<JSFunction>();
return IsSelfHostedFunctionWithName(iterFun, cx->names().dollar_ArrayValues_);
}
/* static */
bool js::ArrayPrototypeIteratorNextFuse::checkInvariant(JSContext* cx) {
auto* proto = cx->global()->maybeGetArrayIteratorPrototype();
if (!proto) {
// Invariant holds if there is no array iterator proto.
return true;
}
// Ensure that %ArrayIteratorPrototype%'s "next" slot is unchanged.
mozilla::Maybe<PropertyInfo> prop = proto->lookupPure(cx->names().next);
if (prop.isNothing() || !prop->isDataProperty()) {
// Next property has been modified, return false, invariant no longer holds.
return false;
}
auto slot = prop->slot();
const Value& nextVal = proto->getSlot(slot);
if (!nextVal.isObject() || !nextVal.toObject().is<JSFunction>()) {
// Next property has been modified, return false, invariant no longer holds.
return false;
}
auto* nextFun = &nextVal.toObject().as<JSFunction>();
return IsSelfHostedFunctionWithName(nextFun, cx->names().ArrayIteratorNext);
}
static bool HasNoReturnName(JSContext* cx, JS::HandleObject proto) {
if (!proto) {
// Invariant holds if there is no array iterator proto.
return true;
}
JS::RootedId returnName(cx, NameToId(cx->names().return_));
// An alternative design here would chain together all the has-return-property
// fuses such that the fuses each express a stronger invariant; for now these
// fuses have only the invariant that each object -itself- has no return
// property.
bool found = true;
if (!HasOwnProperty(cx, proto, returnName, &found)) {
cx->recoverFromOutOfMemory();
return true;
}
return !found;
}
/* static */
bool js::ArrayIteratorPrototypeHasNoReturnProperty::checkInvariant(
JSContext* cx) {
RootedObject proto(cx, cx->global()->maybeGetArrayIteratorPrototype());
if (!proto) {
// Invariant holds if there is no array iterator proto.
return true;
}
return HasNoReturnName(cx, proto);
}
/* static */
bool js::IteratorPrototypeHasNoReturnProperty::checkInvariant(JSContext* cx) {
RootedObject proto(cx, cx->global()->maybeGetIteratorPrototype());
if (!proto) {
// Invariant holds if there is no array iterator proto.
return true;
}
return HasNoReturnName(cx, proto);
}
/* static */
bool js::ArrayIteratorPrototypeHasIteratorProto::checkInvariant(JSContext* cx) {
RootedObject proto(cx, cx->global()->maybeGetArrayIteratorPrototype());
if (!proto) {
// Invariant holds if there is no array iterator proto.
return true;
}
RootedObject iterProto(cx, cx->global()->maybeGetIteratorPrototype());
if (!iterProto) {
MOZ_CRASH("Can we have the array iter proto without the iterator proto?");
return true;
}
return proto->staticPrototype() == iterProto;
}
/* static */
bool js::IteratorPrototypeHasObjectProto::checkInvariant(JSContext* cx) {
RootedObject proto(cx, cx->global()->maybeGetIteratorPrototype());
if (!proto) {
// Invariant holds if there is no array iterator proto.
return true;
}
return proto->staticPrototype() == &cx->global()->getObjectPrototype();
}
/* static */
bool js::ObjectPrototypeHasNoReturnProperty::checkInvariant(JSContext* cx) {
RootedObject proto(cx, &cx->global()->getObjectPrototype());
return HasNoReturnName(cx, proto);
}