libmozjs185-dev 1.8.5-1.0.0-0ubuntu8 / usr / include / js / jspropertycacheinlines.h

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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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 * 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
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 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
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 * The Initial Developer of the Original Code is
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#ifndef jspropertycacheinlines_h___
#define jspropertycacheinlines_h___

#include "jslock.h"
#include "jspropertycache.h"
#include "jsscope.h"

using namespace js;

/* static */ inline bool
PropertyCache::matchShape(JSContext *cx, JSObject *obj, uint32 shape)
{
    return obj->shape() == shape;
}

/*
 * This method is designed to inline the fast path in js_Interpret, so it makes
 * "just-so" restrictions on parameters, e.g. pobj and obj should not be the
 * same variable, since for JOF_PROP-mode opcodes, obj must not be changed
 * because of a cache miss.
 *
 * On return, if atom is null then obj points to the scope chain element in
 * which the property was found, pobj is locked, and entry is valid. If atom is
 * non-null then no object is locked but entry is still set correctly for use,
 * e.g., by PropertyCache::fill and atom should be used as the id to find.
 *
 * We must lock pobj on a hit in order to close races with threads that might
 * be deleting a property from its scope, or otherwise invalidating property
 * caches (on all threads) by re-generating JSObject::shape().
 */
JS_ALWAYS_INLINE void
PropertyCache::test(JSContext *cx, jsbytecode *pc, JSObject *&obj,
                    JSObject *&pobj, PropertyCacheEntry *&entry, JSAtom *&atom)
{
    JS_ASSERT(this == &JS_PROPERTY_CACHE(cx));

    uint32 kshape = obj->shape();
    entry = &table[hash(pc, kshape)];
    PCMETER(pctestentry = entry);
    PCMETER(tests++);
    JS_ASSERT(&obj != &pobj);
    JS_ASSERT(entry->kshape < SHAPE_OVERFLOW_BIT);
    if (entry->kpc == pc && entry->kshape == kshape) {
        JSObject *tmp;
        pobj = obj;
        if (entry->vcapTag() == 1 &&
            (tmp = pobj->getProto()) != NULL) {
            pobj = tmp;
        }

        if (matchShape(cx, pobj, entry->vshape())) {
            PCMETER(pchits++);
            PCMETER(!entry->vcapTag() || protopchits++);
            atom = NULL;
            return;
        }
    }
    atom = fullTest(cx, pc, &obj, &pobj, entry);
    if (atom)
        PCMETER(misses++);
}

JS_ALWAYS_INLINE bool
PropertyCache::testForSet(JSContext *cx, jsbytecode *pc, JSObject *obj,
                          PropertyCacheEntry **entryp, JSObject **obj2p, JSAtom **atomp)
{
    uint32 shape = obj->shape();
    PropertyCacheEntry *entry = &table[hash(pc, shape)];
    *entryp = entry;
    PCMETER(pctestentry = entry);
    PCMETER(tests++);
    PCMETER(settests++);
    JS_ASSERT(entry->kshape < SHAPE_OVERFLOW_BIT);
    if (entry->kpc == pc && entry->kshape == shape)
        return true;

    JSAtom *atom = fullTest(cx, pc, &obj, obj2p, entry);
    JS_ASSERT(atom);

    PCMETER(misses++);
    PCMETER(setmisses++);

    *atomp = atom;
    return false;
}

JS_ALWAYS_INLINE bool
PropertyCache::testForInit(JSRuntime *rt, jsbytecode *pc, JSObject *obj,
                           const js::Shape **shapep, PropertyCacheEntry **entryp)
{
    JS_ASSERT(obj->slotSpan() >= JSSLOT_FREE(obj->getClass()));
    JS_ASSERT(obj->isExtensible());
    uint32 kshape = obj->shape();
    PropertyCacheEntry *entry = &table[hash(pc, kshape)];
    *entryp = entry;
    PCMETER(pctestentry = entry);
    PCMETER(tests++);
    PCMETER(initests++);
    JS_ASSERT(entry->kshape < SHAPE_OVERFLOW_BIT);

    if (entry->kpc == pc &&
        entry->kshape == kshape &&
        entry->vshape() == rt->protoHazardShape) {
        PCMETER(pchits++);
        PCMETER(inipchits++);
        JS_ASSERT(entry->vcapTag() == 0);
        *shapep = entry->vword.toShape();
        JS_ASSERT((*shapep)->writable());
        return true;
    }
    return false;
}

#endif /* jspropertycacheinlines_h___ */