C++ SymbolTableEntry::getIndex方法代码示例

inline bool JSActivation::symbolTableGet(const Identifier& propertyName, PropertySlot& slot)
{
    SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
    if (!entry.isNull()) {
        ASSERT(entry.getIndex() < static_cast<int>(d()->functionExecutable->capturedVariableCount()));
        slot.setRegisterSlot(&registerAt(entry.getIndex()));
        return true;
    }
    return false;
}

inline bool JSActivation::symbolTableGet(const Identifier& propertyName, PropertySlot& slot)
{
    SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
    if (entry.isNull())
        return false;
    if (entry.getIndex() >= m_numCapturedVars)
        return false;

    slot.setValue(registerAt(entry.getIndex()).get());
    return true;
}

inline bool JSActivation::symbolTablePut(const Identifier& propertyName, JSValue value)
{
    ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
    
    SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
    if (entry.isNull())
        return false;
    if (entry.isReadOnly())
        return true;
    ASSERT(entry.getIndex() < static_cast<int>(d()->functionExecutable->capturedVariableCount()));
    registerAt(entry.getIndex()) = value;
    return true;
}

inline bool JSActivation::symbolTablePut(JSGlobalData& globalData, const Identifier& propertyName, JSValue value)
{
    ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
    
    SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
    if (entry.isNull())
        return false;
    if (entry.isReadOnly())
        return true;
    if (entry.getIndex() >= m_numCapturedVars)
        return false;

    registerAt(entry.getIndex()).set(globalData, this, value);
    return true;
}

// Returns true if we found enough information to terminate optimization.
static inline bool abstractAccess(ExecState* exec, JSScope* scope, const Identifier& ident, GetOrPut getOrPut, size_t depth, bool& needsVarInjectionChecks, ResolveOp& op)
{
    if (JSActivation* activation = jsDynamicCast<JSActivation*>(scope)) {
        if (ident == exec->propertyNames().arguments) {
            // We know the property will be at this activation scope, but we don't know how to cache it.
            op = ResolveOp(Dynamic, 0, 0, 0, 0);
            return true;
        }

        SymbolTableEntry entry = activation->symbolTable()->get(ident.impl());
        if (entry.isReadOnly() && getOrPut == Put) {
            // We know the property will be at this activation scope, but we don't know how to cache it.
            op = ResolveOp(Dynamic, 0, 0, 0, 0);
            return true;
        }

        if (!entry.isNull()) {
            op = ResolveOp(makeType(ClosureVar, needsVarInjectionChecks), depth, activation->structure(), 0, entry.getIndex());
            return true;
        }

        if (activation->symbolTable()->usesNonStrictEval())
            needsVarInjectionChecks = true;
        return false;
    }

    if (JSGlobalObject* globalObject = jsDynamicCast<JSGlobalObject*>(scope)) {
        SymbolTableEntry entry = globalObject->symbolTable()->get(ident.impl());
        if (!entry.isNull()) {
            if (getOrPut == Put && entry.isReadOnly()) {
                // We know the property will be at global scope, but we don't know how to cache it.
                op = ResolveOp(Dynamic, 0, 0, 0, 0);
                return true;
            }

            op = ResolveOp(
                makeType(GlobalVar, needsVarInjectionChecks), depth, 0, entry.watchpointSet(),
                reinterpret_cast<uintptr_t>(globalObject->registerAt(entry.getIndex()).slot()));
            return true;
        }

        PropertySlot slot(globalObject);
        if (!globalObject->getOwnPropertySlot(globalObject, exec, ident, slot)
            || !slot.isCacheableValue()
            || !globalObject->structure()->propertyAccessesAreCacheable()
            || (globalObject->structure()->hasReadOnlyOrGetterSetterPropertiesExcludingProto() && getOrPut == Put)) {
            // We know the property will be at global scope, but we don't know how to cache it.
            ASSERT(!scope->next());
            op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, 0, 0, 0);
            return true;
        }

        op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, globalObject->structure(), 0, slot.cachedOffset());
        return true;
    }

    op = ResolveOp(Dynamic, 0, 0, 0, 0);
    return true;
}

bool JSVariableObject::symbolTableGet(const Identifier& propertyName, PropertyDescriptor& descriptor)
{
    SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
    if (!entry.isNull()) {
        descriptor.setDescriptor(registerAt(entry.getIndex()).jsValue(), entry.getAttributes() | DontDelete);
        return true;
    }
    return false;
}

inline bool JSActivation::symbolTablePut(ExecState* exec, PropertyName propertyName, JSValue value, bool shouldThrow)
{
    JSGlobalData& globalData = exec->globalData();
    ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
    
    SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
    if (entry.isNull())
        return false;
    if (entry.isReadOnly()) {
        if (shouldThrow)
            throwTypeError(exec, StrictModeReadonlyPropertyWriteError);
        return true;
    }
    if (m_isTornOff && entry.getIndex() >= m_numCapturedVars)
        return false;

    registerAt(entry.getIndex()).set(globalData, this, value);
    return true;
}

inline bool JSActivation::symbolTableGet(PropertyName propertyName, PropertyDescriptor& descriptor)
{
    SymbolTableEntry entry = symbolTable()->inlineGet(propertyName.publicName());
    if (entry.isNull())
        return false;

    // Defend against the inspector asking for a var after it has been optimized out.
    if (isTornOff() && !isValid(entry))
        return false;

    descriptor.setDescriptor(registerAt(entry.getIndex()).get(), entry.getAttributes());
    return true;
}

inline bool JSLexicalEnvironment::symbolTableGet(PropertyName propertyName, PropertyDescriptor& descriptor)
{
    SymbolTableEntry entry = symbolTable()->inlineGet(propertyName.uid());
    if (entry.isNull())
        return false;

    // Defend against the inspector asking for a var after it has been optimized out.
    if (!isValid(entry))
        return false;

    descriptor.setDescriptor(registerAt(entry.getIndex()).get(), entry.getAttributes());
    return true;
}

inline bool JSActivation::symbolTablePut(ExecState* exec, PropertyName propertyName, JSValue value, bool shouldThrow)
{
    VM& vm = exec->vm();
    ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
    
    SymbolTableEntry entry = symbolTable()->inlineGet(propertyName.publicName());
    if (entry.isNull())
        return false;
    if (entry.isReadOnly()) {
        if (shouldThrow)
            throwTypeError(exec, StrictModeReadonlyPropertyWriteError);
        return true;
    }

    // Defend against the inspector asking for a var after it has been optimized out.
    if (isTornOff() && !isValid(entry))
        return false;

    registerAt(entry.getIndex()).set(vm, this, value);
    return true;
}

// Returns true if we found enough information to terminate optimization.
static inline bool abstractAccess(ExecState* exec, JSScope* scope, const Identifier& ident, GetOrPut getOrPut, size_t depth, bool& needsVarInjectionChecks, ResolveOp& op)
{
    if (JSActivation* activation = jsDynamicCast<JSActivation*>(scope)) {
        if (ident == exec->propertyNames().arguments) {
            // We know the property will be at this activation scope, but we don't know how to cache it.
            op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
            return true;
        }

        SymbolTableEntry entry = activation->symbolTable()->get(ident.impl());
        if (entry.isReadOnly() && getOrPut == Put) {
            // We know the property will be at this activation scope, but we don't know how to cache it.
            op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
            return true;
        }

        if (!entry.isNull()) {
            op = ResolveOp(makeType(ClosureVar, needsVarInjectionChecks), depth, 0, activation, entry.watchpointSet(), entry.getIndex());
            return true;
        }

        if (activation->symbolTable()->usesNonStrictEval())
            needsVarInjectionChecks = true;
        return false;
    }

    if (JSGlobalObject* globalObject = jsDynamicCast<JSGlobalObject*>(scope)) {
        SymbolTableEntry entry = globalObject->symbolTable()->get(ident.impl());
        if (!entry.isNull()) {
            if (getOrPut == Put && entry.isReadOnly()) {
                // We know the property will be at global scope, but we don't know how to cache it.
                op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
                return true;
            }

            op = ResolveOp(
                makeType(GlobalVar, needsVarInjectionChecks), depth, 0, 0, entry.watchpointSet(),
                reinterpret_cast<uintptr_t>(globalObject->registerAt(entry.getIndex()).slot()));
            return true;
        }

        PropertySlot slot(globalObject);
        if (!globalObject->getOwnPropertySlot(globalObject, exec, ident, slot)
            || !slot.isCacheableValue()
            || !globalObject->structure()->propertyAccessesAreCacheable()
            || (globalObject->structure()->hasReadOnlyOrGetterSetterPropertiesExcludingProto() && getOrPut == Put)) {
            // We know the property will be at global scope, but we don't know how to cache it.
            ASSERT(!scope->next());
            op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, 0, 0, 0, 0);
            return true;
        }
        
        WatchpointState state = globalObject->structure()->ensurePropertyReplacementWatchpointSet(exec->vm(), slot.cachedOffset())->state();
        if (state == IsWatched && getOrPut == Put) {
            // The field exists, but because the replacement watchpoint is still intact. This is
            // kind of dangerous. We have two options:
            // 1) Invalidate the watchpoint set. That would work, but it's possible that this code
            //    path never executes - in which case this would be unwise.
            // 2) Have the invalidation happen at run-time. All we have to do is leave the code
            //    uncached. The only downside is slightly more work when this does execute.
            // We go with option (2) here because it seems less evil.
            op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, 0, 0, 0, 0);
        } else
            op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, globalObject->structure(), 0, 0, slot.cachedOffset());
        return true;
    }

    op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
    return true;
}