| /* |
| * Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package jdk.nashorn.internal.codegen; |
| |
| import static jdk.nashorn.internal.runtime.Property.NOT_CONFIGURABLE; |
| import static jdk.nashorn.internal.runtime.Property.NOT_ENUMERABLE; |
| import static jdk.nashorn.internal.runtime.Property.NOT_WRITABLE; |
| |
| import java.lang.invoke.MethodType; |
| import jdk.nashorn.internal.codegen.types.Type; |
| import jdk.nashorn.internal.ir.AccessNode; |
| import jdk.nashorn.internal.ir.CallNode; |
| import jdk.nashorn.internal.ir.Expression; |
| import jdk.nashorn.internal.ir.FunctionNode; |
| import jdk.nashorn.internal.ir.IdentNode; |
| import jdk.nashorn.internal.ir.IndexNode; |
| import jdk.nashorn.internal.ir.Optimistic; |
| import jdk.nashorn.internal.objects.ArrayBufferView; |
| import jdk.nashorn.internal.objects.NativeArray; |
| import jdk.nashorn.internal.runtime.FindProperty; |
| import jdk.nashorn.internal.runtime.JSType; |
| import jdk.nashorn.internal.runtime.Property; |
| import jdk.nashorn.internal.runtime.RecompilableScriptFunctionData; |
| import jdk.nashorn.internal.runtime.ScriptFunction; |
| import jdk.nashorn.internal.runtime.ScriptObject; |
| import jdk.nashorn.internal.runtime.ScriptRuntime; |
| |
| /** |
| * Functionality for using a runtime scope to look up value types. |
| * Used during recompilation. |
| */ |
| final class TypeEvaluator { |
| /** |
| * Type signature for invocation of functions without parameters: we must pass (callee, this) of type |
| * (ScriptFunction, Object) respectively. We also use Object as the return type (we must pass something, |
| * but it'll be ignored; it can't be void, though). |
| */ |
| private static final MethodType EMPTY_INVOCATION_TYPE = MethodType.methodType(Object.class, ScriptFunction.class, Object.class); |
| |
| private final Compiler compiler; |
| private final ScriptObject runtimeScope; |
| |
| TypeEvaluator(final Compiler compiler, final ScriptObject runtimeScope) { |
| this.compiler = compiler; |
| this.runtimeScope = runtimeScope; |
| } |
| |
| /** |
| * Returns true if the expression can be safely evaluated, and its value is an object known to always use |
| * String as the type of its property names retrieved through |
| * {@link ScriptRuntime#toPropertyIterator(Object)}. It is used to avoid optimistic assumptions about its |
| * property name types. |
| * @param expr the expression to test |
| * @return true if the expression can be safely evaluated, and its value is an object known to always use |
| * String as the type of its property iterators. |
| */ |
| boolean hasStringPropertyIterator(final Expression expr) { |
| return evaluateSafely(expr) instanceof ScriptObject; |
| } |
| |
| Type getOptimisticType(final Optimistic node) { |
| assert compiler.useOptimisticTypes(); |
| |
| final int programPoint = node.getProgramPoint(); |
| final Type validType = compiler.getInvalidatedProgramPointType(programPoint); |
| |
| if (validType != null) { |
| return validType; |
| } |
| |
| final Type mostOptimisticType = node.getMostOptimisticType(); |
| final Type evaluatedType = getEvaluatedType(node); |
| |
| if (evaluatedType != null) { |
| if (evaluatedType.widerThan(mostOptimisticType)) { |
| final Type newValidType = evaluatedType.isObject() || evaluatedType.isBoolean() ? Type.OBJECT : evaluatedType; |
| // Update invalidatedProgramPoints so we don't re-evaluate the expression next time. This is a heuristic |
| // as we're doing a tradeoff. Re-evaluating expressions on each recompile takes time, but it might |
| // notice a widening in the type of the expression and thus prevent an unnecessary deoptimization later. |
| // We'll presume though that the types of expressions are mostly stable, so if we evaluated it in one |
| // compilation, we'll keep to that and risk a low-probability deoptimization if its type gets widened |
| // in the future. |
| compiler.addInvalidatedProgramPoint(node.getProgramPoint(), newValidType); |
| } |
| return evaluatedType; |
| } |
| return mostOptimisticType; |
| } |
| |
| private static Type getPropertyType(final ScriptObject sobj, final String name) { |
| final FindProperty find = sobj.findProperty(name, true); |
| if (find == null) { |
| return null; |
| } |
| |
| final Property property = find.getProperty(); |
| final Class<?> propertyClass = property.getType(); |
| if (propertyClass == null) { |
| // propertyClass == null means its value is Undefined. It is probably not initialized yet, so we won't make |
| // a type assumption yet. |
| return null; |
| } else if (propertyClass.isPrimitive()) { |
| return Type.typeFor(propertyClass); |
| } |
| |
| final ScriptObject owner = find.getOwner(); |
| if (property.hasGetterFunction(owner)) { |
| // Can have side effects, so we can't safely evaluate it; since !propertyClass.isPrimitive(), it's Object. |
| return Type.OBJECT; |
| } |
| |
| // Safely evaluate the property, and return the narrowest type for the actual value (e.g. Type.INT for a boxed |
| // integer). |
| final Object value = property.needsDeclaration() ? ScriptRuntime.UNDEFINED : property.getObjectValue(owner, owner); |
| if (value == ScriptRuntime.UNDEFINED) { |
| return null; |
| } |
| return Type.typeFor(JSType.unboxedFieldType(value)); |
| } |
| |
| /** |
| * Declares a symbol name as belonging to a non-scoped local variable during an on-demand compilation of a single |
| * function. This method will add an explicit Undefined binding for the local into the runtime scope if it's |
| * otherwise implicitly undefined so that when an expression is evaluated for the name, it won't accidentally find |
| * an unrelated value higher up the scope chain. It is only required to call this method when doing an optimistic |
| * on-demand compilation. |
| * @param symbolName the name of the symbol that is to be declared as being a non-scoped local variable. |
| */ |
| void declareLocalSymbol(final String symbolName) { |
| assert |
| compiler.useOptimisticTypes() && |
| compiler.isOnDemandCompilation() && |
| runtimeScope != null : |
| "useOptimistic=" + |
| compiler.useOptimisticTypes() + |
| " isOnDemand=" + |
| compiler.isOnDemandCompilation() + |
| " scope="+runtimeScope; |
| |
| if (runtimeScope.findProperty(symbolName, false) == null) { |
| runtimeScope.addOwnProperty(symbolName, NOT_WRITABLE | NOT_ENUMERABLE | NOT_CONFIGURABLE, ScriptRuntime.UNDEFINED); |
| } |
| } |
| |
| private Object evaluateSafely(final Expression expr) { |
| if (expr instanceof IdentNode) { |
| return runtimeScope == null ? null : evaluatePropertySafely(runtimeScope, ((IdentNode)expr).getName()); |
| } |
| |
| if (expr instanceof AccessNode) { |
| final AccessNode accessNode = (AccessNode)expr; |
| final Object base = evaluateSafely(accessNode.getBase()); |
| if (!(base instanceof ScriptObject)) { |
| return null; |
| } |
| return evaluatePropertySafely((ScriptObject)base, accessNode.getProperty()); |
| } |
| |
| return null; |
| } |
| |
| private static Object evaluatePropertySafely(final ScriptObject sobj, final String name) { |
| final FindProperty find = sobj.findProperty(name, true); |
| if (find == null) { |
| return null; |
| } |
| final Property property = find.getProperty(); |
| final ScriptObject owner = find.getOwner(); |
| if (property.hasGetterFunction(owner)) { |
| // Possible side effects; can't evaluate safely |
| return null; |
| } |
| return property.getObjectValue(owner, owner); |
| } |
| |
| |
| private Type getEvaluatedType(final Optimistic expr) { |
| if (expr instanceof IdentNode) { |
| if (runtimeScope == null) { |
| return null; |
| } |
| return getPropertyType(runtimeScope, ((IdentNode)expr).getName()); |
| } else if (expr instanceof AccessNode) { |
| final AccessNode accessNode = (AccessNode)expr; |
| final Object base = evaluateSafely(accessNode.getBase()); |
| if (!(base instanceof ScriptObject)) { |
| return null; |
| } |
| return getPropertyType((ScriptObject)base, accessNode.getProperty()); |
| } else if (expr instanceof IndexNode) { |
| final IndexNode indexNode = (IndexNode)expr; |
| final Object base = evaluateSafely(indexNode.getBase()); |
| if(base instanceof NativeArray || base instanceof ArrayBufferView) { |
| // NOTE: optimistic array getters throw UnwarrantedOptimismException based on the type of their |
| // underlying array storage, not based on values of individual elements. Thus, a LongArrayData will |
| // throw UOE for every optimistic int linkage attempt, even if the long value being returned in the |
| // first invocation would be representable as int. That way, we can presume that the array's optimistic |
| // type is the most optimistic type for which an element getter has a chance of executing successfully. |
| return ((ScriptObject)base).getArray().getOptimisticType(); |
| } |
| } else if (expr instanceof CallNode) { |
| // Currently, we'll only try to guess the return type of immediately invoked function expressions with no |
| // parameters, that is (function() { ... })(). We could do better, but these are all heuristics and we can |
| // gradually introduce them as needed. An easy one would be to do the same for .call(this) idiom. |
| final CallNode callExpr = (CallNode)expr; |
| final Expression fnExpr = callExpr.getFunction(); |
| // Skip evaluation if running with eager compilation as we may violate constraints in RecompilableScriptFunctionData |
| if (fnExpr instanceof FunctionNode && compiler.getContext().getEnv()._lazy_compilation) { |
| final FunctionNode fn = (FunctionNode)fnExpr; |
| if (callExpr.getArgs().isEmpty()) { |
| final RecompilableScriptFunctionData data = compiler.getScriptFunctionData(fn.getId()); |
| if (data != null) { |
| final Type returnType = Type.typeFor(data.getReturnType(EMPTY_INVOCATION_TYPE, runtimeScope)); |
| if (returnType == Type.BOOLEAN) { |
| // We don't have optimistic booleans. In fact, optimistic call sites getting back boolean |
| // currently deoptimize all the way to Object. |
| return Type.OBJECT; |
| } |
| assert returnType == Type.INT || returnType == Type.NUMBER || returnType == Type.OBJECT; |
| return returnType; |
| } |
| } |
| } |
| } |
| |
| return null; |
| } |
| } |
