js/src/jspropertycacheinlines.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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   4  * ***** BEGIN LICENSE BLOCK *****
   5  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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   7  * The contents of this file are subject to the Mozilla Public License Version
   8  * 1.1 (the "License"); you may not use this file except in compliance with
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  10  * http://www.mozilla.org/MPL/
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  12  * Software distributed under the License is distributed on an "AS IS" basis,
  13  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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  16  *
  17  * The Original Code is Mozilla Communicator client code, released
  18  * March 31, 1998.
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  20  * The Initial Developer of the Original Code is
  21  * Mozilla Corporation.
  22  * Portions created by the Initial Developer are Copyright (C) 2010
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  25  * Contributor(s):
  26  *   Igor Bukanov <igor@mir2.org>
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  40  * ***** END LICENSE BLOCK ***** */
  41
  42 #ifndef jspropertycacheinlines_h___
  43 #define jspropertycacheinlines_h___
  44
  45 #include "jslock.h"
  46 #include "jspropertycache.h"
  47 #include "jsscope.h"
  48
  49 using namespace js;
  50
  51 /* static */ inline bool
  52 PropertyCache::matchShape(JSContext *cx, JSObject *obj, uint32 shape)
  53 {
  54     return obj->shape() == shape;
  55 }
  56
  57 /*
  58  * This method is designed to inline the fast path in js_Interpret, so it makes
  59  * "just-so" restrictions on parameters, e.g. pobj and obj should not be the
  60  * same variable, since for JOF_PROP-mode opcodes, obj must not be changed
  61  * because of a cache miss.
  62  *
  63  * On return, if atom is null then obj points to the scope chain element in
  64  * which the property was found, pobj is locked, and entry is valid. If atom is
  65  * non-null then no object is locked but entry is still set correctly for use,
  66  * e.g., by PropertyCache::fill and atom should be used as the id to find.
  67  *
  68  * We must lock pobj on a hit in order to close races with threads that might
  69  * be deleting a property from its scope, or otherwise invalidating property
  70  * caches (on all threads) by re-generating JSObject::shape().
  71  */
  72 JS_ALWAYS_INLINE void
  73 PropertyCache::test(JSContext *cx, jsbytecode *pc, JSObject *&obj,
  74                     JSObject *&pobj, PropertyCacheEntry *&entry, JSAtom *&atom)
  75 {
  76     JS_ASSERT(this == &JS_PROPERTY_CACHE(cx));
  77
  78     uint32 kshape = obj->shape();
  79     entry = &table[hash(pc, kshape)];
  80     PCMETER(pctestentry = entry);
  81     PCMETER(tests++);
  82     JS_ASSERT(&obj != &pobj);
  83     JS_ASSERT(entry->kshape < SHAPE_OVERFLOW_BIT);
  84     if (entry->kpc == pc && entry->kshape == kshape) {
  85         JSObject *tmp;
  86         pobj = obj;
  87         if (entry->vcapTag() == 1 &&
  88             (tmp = pobj->getProto()) != NULL) {
  89             pobj = tmp;
  90         }
  91
  92         if (matchShape(cx, pobj, entry->vshape())) {
  93             PCMETER(pchits++);
  94             PCMETER(!entry->vcapTag() || protopchits++);
  95             atom = NULL;
  96             return;
  97         }
  98     }
  99     atom = fullTest(cx, pc, &obj, &pobj, entry);
 100     if (atom)
 101         PCMETER(misses++);
 102 }
 103
 104 JS_ALWAYS_INLINE bool
 105 PropertyCache::testForSet(JSContext *cx, jsbytecode *pc, JSObject *obj,
 106                           PropertyCacheEntry **entryp, JSObject **obj2p, JSAtom **atomp)
 107 {
 108     uint32 shape = obj->shape();
 109     PropertyCacheEntry *entry = &table[hash(pc, shape)];
 110     *entryp = entry;
 111     PCMETER(pctestentry = entry);
 112     PCMETER(tests++);
 113     PCMETER(settests++);
 114     JS_ASSERT(entry->kshape < SHAPE_OVERFLOW_BIT);
 115     if (entry->kpc == pc && entry->kshape == shape)
 116         return true;
 117
 118     JSAtom *atom = fullTest(cx, pc, &obj, obj2p, entry);
 119     JS_ASSERT(atom);
 120
 121     PCMETER(misses++);
 122     PCMETER(setmisses++);
 123
 124     *atomp = atom;
 125     return false;
 126 }
 127
 128 JS_ALWAYS_INLINE bool
 129 PropertyCache::testForInit(JSRuntime *rt, jsbytecode *pc, JSObject *obj,
 130                            const js::Shape **shapep, PropertyCacheEntry **entryp)
 131 {
 132     JS_ASSERT(obj->slotSpan() >= JSSLOT_FREE(obj->getClass()));
 133     JS_ASSERT(obj->isExtensible());
 134     uint32 kshape = obj->shape();
 135     PropertyCacheEntry *entry = &table[hash(pc, kshape)];
 136     *entryp = entry;
 137     PCMETER(pctestentry = entry);
 138     PCMETER(tests++);
 139     PCMETER(initests++);
 140     JS_ASSERT(entry->kshape < SHAPE_OVERFLOW_BIT);
 141
 142     if (entry->kpc == pc &&
 143         entry->kshape == kshape &&
 144         entry->vshape() == rt->protoHazardShape) {
 145         PCMETER(pchits++);
 146         PCMETER(inipchits++);
 147         JS_ASSERT(entry->vcapTag() == 0);
 148         *shapep = entry->vword.toShape();
 149         JS_ASSERT((*shapep)->writable());
 150         return true;
 151     }
 152     return false;
 153 }
 154
 155 #endif /* jspropertycacheinlines_h___ */