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
   6  *
   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
  14  * for the specific language governing rights and limitations under the
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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
  23  * the Initial Developer. All Rights Reserved.
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  25  * Contributor(s):
  26  *   Igor Bukanov <igor@mir2.org>
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  39  *
  40  * ***** END LICENSE BLOCK ***** */
  41
  42 #ifndef jspropertycacheinlines_h___
  43 #define jspropertycacheinlines_h___
  44
  45 #include "jspropertycache.h"
  46 #include "jsscope.h"
  47
  48 using namespace js;
  49
  50 /* static */ inline bool
  51 PropertyCache::matchShape(JSContext *cx, JSObject *obj, uint32 shape)
  52 {
  53     return CX_OWNS_OBJECT_TITLE(cx, obj) && obj->shape() == shape;
  54 }
  55
  56 /*
  57  * This method is designed to inline the fast path in js_Interpret, so it makes
  58  * "just-so" restrictions on parameters, e.g. pobj and obj should not be the
  59  * same variable, since for JOF_PROP-mode opcodes, obj must not be changed
  60  * because of a cache miss.
  61  *
  62  * On return, if atom is null then obj points to the scope chain element in
  63  * which the property was found, pobj is locked, and entry is valid. If atom is
  64  * non-null then no object is locked but entry is still set correctly for use,
  65  * e.g., by PropertyCache::fill and atom should be used as the id to find.
  66  *
  67  * We must lock pobj on a hit in order to close races with threads that might
  68  * be deleting a property from its scope, or otherwise invalidating property
  69  * caches (on all threads) by re-generating scope->shape.
  70  */
  71 JS_ALWAYS_INLINE void
  72 PropertyCache::test(JSContext *cx, jsbytecode *pc, JSObject *&obj,
  73                     JSObject *&pobj, PropertyCacheEntry *&entry, JSAtom *&atom)
  74 {
  75     JS_ASSERT(this == &JS_PROPERTY_CACHE(cx));
  76
  77     uint32 kshape = obj->map->shape;
  78     entry = &table[hash(pc, kshape)];
  79     PCMETER(pctestentry = entry);
  80     PCMETER(tests++);
  81     JS_ASSERT(&obj != &pobj);
  82     JS_ASSERT(entry->kshape < SHAPE_OVERFLOW_BIT);
  83     if (entry->kpc == pc && entry->kshape == kshape) {
  84         JSObject *tmp;
  85         pobj = obj;
  86         if (entry->vcapTag() == 1 &&
  87             (tmp = pobj->getProto()) != NULL) {
  88             pobj = tmp;
  89         }
  90
  91         if (matchShape(cx, pobj, entry->vshape())) {
  92             PCMETER(pchits++);
  93             PCMETER(!entry->vcapTag() || protopchits++);
  94             atom = NULL;
  95             return;
  96         }
  97     }
  98     atom = fullTest(cx, pc, &obj, &pobj, entry);
  99     if (atom)
 100         PCMETER(misses++);
 101 }
 102
 103 JS_ALWAYS_INLINE bool
 104 PropertyCache::testForSet(JSContext *cx, jsbytecode *pc, JSObject *obj,
 105                           PropertyCacheEntry **entryp, JSObject **obj2p, JSAtom **atomp)
 106 {
 107     uint32 shape = obj->map->shape;
 108     PropertyCacheEntry *entry = &table[hash(pc, shape)];
 109     *entryp = entry;
 110     PCMETER(pctestentry = entry);
 111     PCMETER(tests++);
 112     PCMETER(settests++);
 113     JS_ASSERT(entry->kshape < SHAPE_OVERFLOW_BIT);
 114     if (entry->kpc == pc && entry->kshape == shape && matchShape(cx, obj, shape))
 115         return true;
 116
 117 #ifdef DEBUG
 118     JSObject *orig = obj;
 119 #endif
 120     JSAtom *atom = fullTest(cx, pc, &obj, obj2p, entry);
 121     if (atom) {
 122         PCMETER(misses++);
 123         PCMETER(setmisses++);
 124     } else {
 125         JS_ASSERT(obj == orig);
 126     }
 127     *atomp = atom;
 128     return false;
 129 }
 130
 131 JS_ALWAYS_INLINE bool
 132 PropertyCache::testForInit(JSRuntime *rt, jsbytecode *pc, JSObject *obj, JSScope *scope,
 133                            JSScopeProperty **spropp, PropertyCacheEntry **entryp)
 134 {
 135     JS_ASSERT(scope->object == obj);
 136     JS_ASSERT(!scope->sealed());
 137     uint32 kshape = scope->shape;
 138     PropertyCacheEntry *entry = &table[hash(pc, kshape)];
 139     *entryp = entry;
 140     PCMETER(pctestentry = entry);
 141     PCMETER(tests++);
 142     PCMETER(initests++);
 143     JS_ASSERT(entry->kshape < SHAPE_OVERFLOW_BIT);
 144
 145     if (entry->kpc == pc &&
 146         entry->kshape == kshape &&
 147         entry->vshape() == rt->protoHazardShape) {
 148         PCMETER(pchits++);
 149         PCMETER(inipchits++);
 150         JS_ASSERT(entry->vcapTag() == 0);
 151         *spropp = entry->vword.toSprop();
 152         JS_ASSERT((*spropp)->writable());
 153         return true;
 154     }
 155     return false;
 156 }
 157
 158 #endif /* jspropertycacheinlines_h___ */