https://github.com/mozilla/gecko-dev
Tip revision: 51d564290afba99b1655ea4c399a60ce2e9811c8 authored by seabld on 02 January 2013, 01:33:14 UTC
Added tag SEAMONKEY_2_15b6_RELEASE for changeset FIREFOX_18_0b7_BUILD1. CLOSED TREE a=release
Added tag SEAMONKEY_2_15b6_RELEASE for changeset FIREFOX_18_0b7_BUILD1. CLOSED TREE a=release
Tip revision: 51d5642
jspropertycache.h
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sw=4 et tw=98:
*
* 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 jspropertycache_h___
#define jspropertycache_h___
#include "jsapi.h"
#include "jsprvtd.h"
#include "jstypes.h"
#include "vm/String.h"
namespace js {
/*
* Property cache with structurally typed capabilities for invalidation, for
* polymorphic callsite method/get/set speedups. For details, see
* <https://developer.mozilla.org/en/SpiderMonkey/Internals/Property_cache>.
*/
class PropertyCache;
struct PropertyCacheEntry
{
jsbytecode *kpc; /* pc of cache-testing bytecode */
Shape *kshape; /* shape of direct (key) object */
Shape *pshape; /* shape of owning object */
Shape *prop; /* shape of accessed property */
friend class PropertyCache;
private:
/* Index into the prototype chain from the object for this entry. */
uint8_t protoIndex;
public:
static const size_t MaxProtoIndex = 15;
/*
* True iff the property lookup will find an own property on the object if
* the entry matches.
*
* This test is applicable only to property lookups, not to identifier
* lookups. It is meaningless to ask this question of an entry for an
* identifier lookup.
*/
bool isOwnPropertyHit() const { return protoIndex == 0; }
/*
* True iff the property lookup will find the property on the prototype of
* the object if the entry matches.
*
* This test is applicable only to property lookups, not to identifier
* lookups. It is meaningless to ask this question of an entry for an
* identifier lookup.
*/
bool isPrototypePropertyHit() const { return protoIndex == 1; }
void assign(jsbytecode *kpc, Shape *kshape, Shape *pshape, Shape *prop, unsigned protoIndex) {
JS_ASSERT(protoIndex <= MaxProtoIndex);
this->kpc = kpc;
this->kshape = kshape;
this->pshape = pshape;
this->prop = prop;
this->protoIndex = uint8_t(protoIndex);
}
};
/*
* Special value for functions returning PropertyCacheEntry * to distinguish
* between failure and no no-cache-fill cases.
*/
#define JS_NO_PROP_CACHE_FILL ((js::PropertyCacheEntry *) NULL + 1)
#if defined DEBUG_brendan || defined DEBUG_brendaneich
#define JS_PROPERTY_CACHE_METERING 1
#endif
class PropertyCache
{
private:
enum {
SIZE_LOG2 = 12,
SIZE = JS_BIT(SIZE_LOG2),
MASK = JS_BITMASK(SIZE_LOG2)
};
PropertyCacheEntry table[SIZE];
JSBool empty;
public:
#ifdef JS_PROPERTY_CACHE_METERING
PropertyCacheEntry *pctestentry; /* entry of the last PC-based test */
uint32_t fills; /* number of cache entry fills */
uint32_t nofills; /* couldn't fill (e.g. default get) */
uint32_t rofills; /* set on read-only prop can't fill */
uint32_t disfills; /* fill attempts on disabled cache */
uint32_t oddfills; /* fill attempt after setter deleted */
uint32_t add2dictfills; /* fill attempt on dictionary object */
uint32_t modfills; /* fill that rehashed to a new entry */
uint32_t brandfills; /* scope brandings to type structural
method fills */
uint32_t noprotos; /* resolve-returned non-proto pobj */
uint32_t longchains; /* overlong scope and/or proto chain */
uint32_t recycles; /* cache entries recycled by fills */
uint32_t tests; /* cache probes */
uint32_t pchits; /* fast-path polymorphic op hits */
uint32_t protopchits; /* pchits hitting immediate prototype */
uint32_t initests; /* cache probes from JSOP_INITPROP */
uint32_t inipchits; /* init'ing next property pchit case */
uint32_t inipcmisses; /* init'ing next property pc misses */
uint32_t settests; /* cache probes from JOF_SET opcodes */
uint32_t addpchits; /* adding next property pchit case */
uint32_t setpchits; /* setting existing property pchit */
uint32_t setpcmisses; /* setting/adding property pc misses */
uint32_t setmisses; /* JSOP_SET{NAME,PROP} total misses */
uint32_t kpcmisses; /* slow-path key id == atom misses */
uint32_t kshapemisses; /* slow-path key object misses */
uint32_t vcapmisses; /* value capability misses */
uint32_t misses; /* cache misses */
uint32_t flushes; /* cache flushes */
uint32_t pcpurges; /* shadowing purges on proto chain */
# define PCMETER(x) x
#else
# define PCMETER(x) ((void)0)
#endif
PropertyCache() {
PodZero(this);
}
private:
static inline uintptr_t
hash(jsbytecode *pc, const Shape *kshape)
{
return (((uintptr_t(pc) >> SIZE_LOG2) ^ uintptr_t(pc) ^ ((uintptr_t)kshape >> 3)) & MASK);
}
static inline bool matchShape(JSContext *cx, JSObject *obj, uint32_t shape);
PropertyName *
fullTest(JSContext *cx, jsbytecode *pc, JSObject **objp,
JSObject **pobjp, PropertyCacheEntry *entry);
#ifdef DEBUG
void assertEmpty();
#else
inline void assertEmpty() {}
#endif
public:
JS_ALWAYS_INLINE void test(JSContext *cx, jsbytecode *pc,
JSObject *&obj, JSObject *&pobj,
PropertyCacheEntry *&entry, PropertyName *&name);
/*
* Test for cached information about a property set on *objp at pc.
*
* On a hit, set *entryp to the entry and return true.
*
* On a miss, set *namep to the name of the property being set and return false.
*/
JS_ALWAYS_INLINE bool testForSet(JSContext *cx, jsbytecode *pc, JSObject *obj,
PropertyCacheEntry **entryp, JSObject **obj2p,
PropertyName **namep);
/*
* Fill property cache entry for key cx->fp->pc, optimized value word
* computed from obj and shape, and entry capability forged from
* obj->shape() and an 8-bit protoIndex.
*
* Return the filled cache entry or JS_NO_PROP_CACHE_FILL if caching was
* not possible.
*/
PropertyCacheEntry *fill(JSContext *cx, JSObject *obj, JSObject *pobj, js::Shape *shape);
void purge(JSRuntime *rt);
/* Restore an entry that may have been purged during a GC. */
void restore(PropertyCacheEntry *entry);
};
} /* namespace js */
#endif /* jspropertycache_h___ */