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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
#ifndef vm_PropMap_inl_h
#define vm_PropMap_inl_h
#include "vm/PropMap.h"
#include "gc/Cell.h"
#include "gc/Zone.h"
#include "vm/JSContext.h"
#include "gc/GCContext-inl.h"
namespace js {
inline AutoKeepPropMapTables::AutoKeepPropMapTables(JSContext* cx)
: cx_(cx), prev_(cx->zone()->keepPropMapTables()) {
cx->zone()->setKeepPropMapTables(true);
}
inline AutoKeepPropMapTables::~AutoKeepPropMapTables() {
cx_->zone()->setKeepPropMapTables(prev_);
}
// static
MOZ_ALWAYS_INLINE PropMap* PropMap::lookupLinear(uint32_t mapLength,
PropertyKey key,
uint32_t* index) {
MOZ_ASSERT(mapLength > 0);
MOZ_ASSERT(mapLength <= Capacity);
// This function is very hot, so we use a macro to manually unroll the lookups
// below. Some compilers are able to unroll the equivalent loops, but they're
// not very consistent about this. The code below results in reasonable code
// with all compilers we tested.
static_assert(PropMap::Capacity == 8,
"Code below needs to change when capacity changes");
#define LOOKUP_KEY(idx) \
if (mapLength > idx && getKey(idx) == key) { \
*index = idx; \
return this; \
}
LOOKUP_KEY(0);
LOOKUP_KEY(1);
LOOKUP_KEY(2);
LOOKUP_KEY(3);
LOOKUP_KEY(4);
LOOKUP_KEY(5);
LOOKUP_KEY(6);
LOOKUP_KEY(7);
#undef LOOKUP_KEY
PropMap* map = this;
while (map->hasPrevious()) {
map = map->asLinked()->previous();
#define LOOKUP_KEY(idx) \
if (map->getKey(idx) == key) { \
*index = idx; \
return map; \
}
LOOKUP_KEY(0);
LOOKUP_KEY(1);
LOOKUP_KEY(2);
LOOKUP_KEY(3);
LOOKUP_KEY(4);
LOOKUP_KEY(5);
LOOKUP_KEY(6);
LOOKUP_KEY(7);
#undef LOOKUP_INDEX
}
return nullptr;
}
MOZ_ALWAYS_INLINE PropMap* PropMapTable::lookup(PropMap* map,
uint32_t mapLength,
PropertyKey key,
uint32_t* index) {
JS::AutoCheckCannotGC nogc;
MOZ_ASSERT(map->asLinked()->maybeTable(nogc) == this);
PropMapAndIndex entry;
if (lookupInCache(key, &entry)) {
if (entry.isNone()) {
return nullptr;
}
} else {
auto p = lookupRaw(key);
addToCache(key, p);
if (!p) {
return nullptr;
}
entry = *p;
}
// For the last map, only properties in [0, mapLength) are part of the object.
if (entry.map() == map && entry.index() >= mapLength) {
return nullptr;
}
*index = entry.index();
return entry.map();
}
// static
MOZ_ALWAYS_INLINE PropMap* PropMap::lookupPure(uint32_t mapLength,
PropertyKey key,
uint32_t* index) {
if (canHaveTable()) {
JS::AutoCheckCannotGC nogc;
if (PropMapTable* table = asLinked()->maybeTable(nogc)) {
return table->lookup(this, mapLength, key, index);
}
}
return lookupLinear(mapLength, key, index);
}
// static
MOZ_ALWAYS_INLINE PropMap* PropMap::lookup(JSContext* cx, uint32_t mapLength,
PropertyKey key, uint32_t* index) {
if (canHaveTable()) {
JS::AutoCheckCannotGC nogc;
if (PropMapTable* table = asLinked()->ensureTable(cx, nogc);
MOZ_LIKELY(table)) {
return table->lookup(this, mapLength, key, index);
}
// OOM. Do a linear lookup.
cx->recoverFromOutOfMemory();
}
return lookupLinear(mapLength, key, index);
}
// static
inline void SharedPropMap::getPrevious(MutableHandle<SharedPropMap*> map,
uint32_t* mapLength) {
// Update the map/mapLength pointers to "remove" the last property. In most
// cases we can simply decrement *mapLength, but if *mapLength is 1 we have to
// either start at the previous map or set map/mapLength to nullptr/zero
// (if there is just one property).
MOZ_ASSERT(map);
MOZ_ASSERT(*mapLength > 0);
if (*mapLength > 1) {
*mapLength -= 1;
return;
}
if (map->hasPrevious()) {
map.set(map->asNormal()->previous());
*mapLength = PropMap::Capacity;
return;
}
map.set(nullptr);
*mapLength = 0;
}
// static
inline bool PropMap::lookupForRemove(JSContext* cx, PropMap* map,
uint32_t mapLength, PropertyKey key,
const AutoKeepPropMapTables& keep,
PropMap** propMap, uint32_t* propIndex,
PropMapTable** table,
PropMapTable::Ptr* ptr) {
if (map->isDictionary()) {
*table = map->asLinked()->ensureTable(cx, keep);
if (!*table) {
return false;
}
*ptr = (*table)->lookupRaw(key);
*propMap = *ptr ? (*ptr)->map() : nullptr;
*propIndex = *ptr ? (*ptr)->index() : 0;
return true;
}
*table = nullptr;
*propMap = map->lookup(cx, mapLength, key, propIndex);
return true;
}
MOZ_ALWAYS_INLINE bool SharedPropMap::shouldConvertToDictionaryForAdd() const {
if (MOZ_LIKELY(numPreviousMaps() < NumPrevMapsConsiderDictionary)) {
return false;
}
if (numPreviousMaps() >= NumPrevMapsAlwaysDictionary) {
return true;
}
// More heuristics: if one of the last two maps has had a dictionary
// conversion before, or is branchy (indicated by parent != previous), convert
// to dictionary.
const SharedPropMap* curMap = this;
for (size_t i = 0; i < 2; i++) {
if (curMap->hadDictionaryConversion()) {
return true;
}
if (curMap->treeDataRef().parent.map() != curMap->asNormal()->previous()) {
return true;
}
curMap = curMap->asNormal()->previous();
}
return false;
}
inline void SharedPropMap::sweep(JS::GCContext* gcx) {
// We detach the child from the parent if the parent is reachable.
//
// This test depends on PropMap arenas not being freed until after we finish
// incrementally sweeping them. If that were not the case the parent pointer
// could point to a marked cell that had been deallocated and then
// reallocated, since allocating a cell in a zone that is being marked will
// set the mark bit for that cell.
MOZ_ASSERT(zone()->isGCSweeping());
MOZ_ASSERT_IF(hasPrevious(), asLinked()->previous()->zone() == zone());
SharedPropMapAndIndex parent = treeDataRef().parent;
if (!parent.isNone() && TenuredThingIsMarkedAny(parent.map())) {
parent.map()->removeChild(gcx, this);
}
}
inline void SharedPropMap::finalize(JS::GCContext* gcx) {
if (canHaveTable() && asLinked()->hasTable()) {
asLinked()->purgeTable(gcx);
}
if (hasChildrenSet()) {
SharedChildrenPtr& childrenRef = treeDataRef().children;
gcx->delete_(this, childrenRef.toChildrenSet(), MemoryUse::PropMapChildren);
childrenRef.setNone();
}
}
inline void DictionaryPropMap::finalize(JS::GCContext* gcx) {
if (asLinked()->hasTable()) {
asLinked()->purgeTable(gcx);
}
}
} // namespace js
#endif /* vm_PropMap_inl_h */