https://github.com/mozilla/gecko-dev
Tip revision: 826f2ac0acde5b0eac0b8886d27db761bbb3f623 authored by ffxbld on 15 June 2011, 21:16:26 UTC
Added tag FIREFOX_5_0_BUILD1 for changeset 7b56ff900c2a. CLOSED TREE a=release
Added tag FIREFOX_5_0_BUILD1 for changeset 7b56ff900c2a. CLOSED TREE a=release
Tip revision: 826f2ac
jspropertycache.h
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sw=4 et tw=98:
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef jspropertycache_h___
#define jspropertycache_h___
#include "jsapi.h"
#include "jsprvtd.h"
#include "jstypes.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>.
*/
/* Property cache value capabilities. */
enum {
PCVCAP_PROTOBITS = 4,
PCVCAP_PROTOSIZE = JS_BIT(PCVCAP_PROTOBITS),
PCVCAP_PROTOMASK = JS_BITMASK(PCVCAP_PROTOBITS),
PCVCAP_SCOPEBITS = 4,
PCVCAP_SCOPESIZE = JS_BIT(PCVCAP_SCOPEBITS),
PCVCAP_SCOPEMASK = JS_BITMASK(PCVCAP_SCOPEBITS),
PCVCAP_TAGBITS = PCVCAP_PROTOBITS + PCVCAP_SCOPEBITS,
PCVCAP_TAGMASK = JS_BITMASK(PCVCAP_TAGBITS)
};
const uint32 SHAPE_OVERFLOW_BIT = JS_BIT(32 - PCVCAP_TAGBITS);
/*
* Property cache value. This is simply a tagged union:
* PCVal = (JSObject * | uint32 | js::Shape *).
* It is the type of PropertyCacheEntry::vword and combines with the tag bits
* of PropertyCacheEntry::vcap to tell how to get or set the property, once a
* property cache hit is validated.
*
* PropertyCache::purge depends on the bit-pattern of a null PCVal being 0.
*/
class PCVal
{
private:
enum {
OBJECT = 0,
SLOT = 1,
SHAPE = 2,
TAG = 3
};
jsuword v;
public:
bool isNull() const { return v == 0; }
void setNull() { v = 0; }
bool isFunObj() const { return (v & TAG) == OBJECT; }
JSObject &toFunObj() const {
JS_ASSERT(isFunObj());
return *reinterpret_cast<JSObject *>(v);
}
void setFunObj(JSObject &obj) {
v = reinterpret_cast<jsuword>(&obj);
}
bool isSlot() const { return v & SLOT; }
uint32 toSlot() const { JS_ASSERT(isSlot()); return uint32(v) >> 1; }
void setSlot(uint32 slot) { v = (jsuword(slot) << 1) | SLOT; }
bool isShape() const { return (v & TAG) == SHAPE; }
const js::Shape *toShape() const {
JS_ASSERT(isShape());
return reinterpret_cast<js::Shape *>(v & ~TAG);
}
void setShape(const js::Shape *shape) {
JS_ASSERT(shape);
v = reinterpret_cast<jsuword>(shape) | SHAPE;
}
};
struct PropertyCacheEntry
{
jsbytecode *kpc; /* pc of cache-testing bytecode */
jsuword kshape; /* shape of direct (key) object */
jsuword vcap; /* value capability, see above */
PCVal vword; /* value word, see PCVal above */
bool adding() const { return vcapTag() == 0 && kshape != vshape(); }
bool directHit() const { return vcapTag() == 0 && kshape == vshape(); }
jsuword vcapTag() const { return vcap & PCVCAP_TAGMASK; }
uint32 vshape() const { return uint32(vcap >> PCVCAP_TAGBITS); }
jsuword scopeIndex() const { return (vcap >> PCVCAP_PROTOBITS) & PCVCAP_SCOPEMASK; }
jsuword protoIndex() const { return vcap & PCVCAP_PROTOMASK; }
void assign(jsbytecode *kpc, jsuword kshape, jsuword vshape,
uintN scopeIndex, uintN protoIndex, PCVal vword) {
JS_ASSERT(kshape < SHAPE_OVERFLOW_BIT);
JS_ASSERT(vshape < SHAPE_OVERFLOW_BIT);
JS_ASSERT(scopeIndex <= PCVCAP_SCOPEMASK);
JS_ASSERT(protoIndex <= PCVCAP_PROTOMASK);
this->kpc = kpc;
this->kshape = kshape;
this->vcap = (vshape << PCVCAP_TAGBITS) | (scopeIndex << PCVCAP_PROTOBITS) | protoIndex;
this->vword = vword;
}
};
/*
* 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 fills; /* number of cache entry fills */
uint32 nofills; /* couldn't fill (e.g. default get) */
uint32 rofills; /* set on read-only prop can't fill */
uint32 disfills; /* fill attempts on disabled cache */
uint32 oddfills; /* fill attempt after setter deleted */
uint32 add2dictfills; /* fill attempt on dictionary object */
uint32 modfills; /* fill that rehashed to a new entry */
uint32 brandfills; /* scope brandings to type structural
method fills */
uint32 noprotos; /* resolve-returned non-proto pobj */
uint32 longchains; /* overlong scope and/or proto chain */
uint32 recycles; /* cache entries recycled by fills */
uint32 tests; /* cache probes */
uint32 pchits; /* fast-path polymorphic op hits */
uint32 protopchits; /* pchits hitting immediate prototype */
uint32 initests; /* cache probes from JSOP_INITPROP */
uint32 inipchits; /* init'ing next property pchit case */
uint32 inipcmisses; /* init'ing next property pc misses */
uint32 settests; /* cache probes from JOF_SET opcodes */
uint32 addpchits; /* adding next property pchit case */
uint32 setpchits; /* setting existing property pchit */
uint32 setpcmisses; /* setting/adding property pc misses */
uint32 setmisses; /* JSOP_SET{NAME,PROP} total misses */
uint32 kpcmisses; /* slow-path key id == atom misses */
uint32 kshapemisses; /* slow-path key object misses */
uint32 vcapmisses; /* value capability misses */
uint32 misses; /* cache misses */
uint32 flushes; /* cache flushes */
uint32 pcpurges; /* shadowing purges on proto chain */
# define PCMETER(x) x
#else
# define PCMETER(x) ((void)0)
#endif
PropertyCache() {
PodZero(this);
}
private:
/*
* Add kshape rather than xor it to avoid collisions between nearby bytecode
* that are evolving an object by setting successive properties, incrementing
* the object's shape on each set.
*/
static inline jsuword
hash(jsbytecode *pc, jsuword kshape)
{
return ((((jsuword(pc) >> SIZE_LOG2) ^ jsuword(pc)) + kshape) & MASK);
}
static inline bool matchShape(JSContext *cx, JSObject *obj, uint32 shape);
JS_REQUIRES_STACK JSAtom *fullTest(JSContext *cx, jsbytecode *pc, JSObject **objp,
JSObject **pobjp, PropertyCacheEntry *entry);
#ifdef DEBUG
void assertEmpty();
#else
inline void assertEmpty() {}
#endif
public:
JS_ALWAYS_INLINE JS_REQUIRES_STACK void test(JSContext *cx, jsbytecode *pc,
JSObject *&obj, JSObject *&pobj,
PropertyCacheEntry *&entry, JSAtom *&atom);
/*
* 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 *atomp 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,
JSAtom **atomp);
/*
* Test for cached information about creating a new own data property on obj at pc.
*
* On a hit, set *shapep to an shape from the property tree describing the
* new property as well as all existing properties on obj and return
* true. Otherwise return false.
*
* Hit or miss, *entryp receives a pointer to the property cache entry.
*/
JS_ALWAYS_INLINE bool testForInit(JSRuntime *rt, jsbytecode *pc, JSObject *obj,
const js::Shape **shapep, PropertyCacheEntry **entryp);
/*
* Fill property cache entry for key cx->fp->pc, optimized value word
* computed from obj and shape, and entry capability forged from 24-bit
* obj->shape(), 4-bit scopeIndex, and 4-bit protoIndex.
*
* Return the filled cache entry or JS_NO_PROP_CACHE_FILL if caching was
* not possible.
*/
JS_REQUIRES_STACK PropertyCacheEntry *fill(JSContext *cx, JSObject *obj, uintN scopeIndex,
uintN protoIndex, JSObject *pobj,
const js::Shape *shape, JSBool adding = false);
void purge(JSContext *cx);
void purgeForScript(JSContext *cx, JSScript *script);
/* Restore an entry that may have been purged during a GC. */
void restore(PropertyCacheEntry *entry);
};
} /* namespace js */
#endif /* jspropertycache_h___ */