--- old/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/TypeEvaluator.java 2020-04-15 18:47:19.000000000 +0530 +++ /dev/null 2020-04-15 18:47:19.000000000 +0530 @@ -1,251 +0,0 @@ -/* - * 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; - } -}