| /* |
| * Copyright (c) 2016, 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. |
| * |
| * 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 org.graalvm.compiler.core.common.spi; |
| |
| import org.graalvm.compiler.debug.GraalError; |
| import org.graalvm.compiler.options.Option; |
| import org.graalvm.compiler.options.OptionValue; |
| |
| import jdk.vm.ci.meta.JavaConstant; |
| import jdk.vm.ci.meta.JavaType; |
| import jdk.vm.ci.meta.MetaAccessProvider; |
| import jdk.vm.ci.meta.ResolvedJavaField; |
| import jdk.vm.ci.meta.ResolvedJavaType; |
| |
| /** |
| * Utility for default constant folding semantics for Java fields. |
| */ |
| public abstract class JavaConstantFieldProvider implements ConstantFieldProvider { |
| |
| static class Options { |
| @Option(help = "Determines whether to treat final fields with default values as constant.")// |
| public static final OptionValue<Boolean> TrustFinalDefaultFields = new OptionValue<>(true); |
| } |
| |
| protected JavaConstantFieldProvider(MetaAccessProvider metaAccess) { |
| try { |
| this.stringValueField = metaAccess.lookupJavaField(String.class.getDeclaredField("value")); |
| this.stringHashField = metaAccess.lookupJavaField(String.class.getDeclaredField("hash")); |
| } catch (NoSuchFieldException | SecurityException e) { |
| throw new GraalError(e); |
| } |
| } |
| |
| @Override |
| public <T> T readConstantField(ResolvedJavaField field, ConstantFieldTool<T> tool) { |
| if (isStableField(field, tool)) { |
| JavaConstant value = tool.readValue(); |
| if (value != null && isStableFieldValueConstant(field, value, tool)) { |
| return foldStableArray(value, field, tool); |
| } |
| } |
| if (isFinalField(field, tool)) { |
| JavaConstant value = tool.readValue(); |
| if (value != null && isFinalFieldValueConstant(field, value, tool)) { |
| return tool.foldConstant(value); |
| } |
| } |
| return null; |
| } |
| |
| protected <T> T foldStableArray(JavaConstant value, ResolvedJavaField field, ConstantFieldTool<T> tool) { |
| return tool.foldStableArray(value, getArrayDimension(field.getType()), isDefaultStableField(field, tool)); |
| } |
| |
| private static int getArrayDimension(JavaType type) { |
| int dimensions = 0; |
| JavaType componentType = type; |
| while ((componentType = componentType.getComponentType()) != null) { |
| dimensions++; |
| } |
| return dimensions; |
| } |
| |
| private static boolean isArray(ResolvedJavaField field) { |
| JavaType fieldType = field.getType(); |
| return fieldType instanceof ResolvedJavaType && ((ResolvedJavaType) fieldType).isArray(); |
| } |
| |
| @SuppressWarnings("unused") |
| protected boolean isStableFieldValueConstant(ResolvedJavaField field, JavaConstant value, ConstantFieldTool<?> tool) { |
| return !value.isDefaultForKind(); |
| } |
| |
| @SuppressWarnings("unused") |
| protected boolean isFinalFieldValueConstant(ResolvedJavaField field, JavaConstant value, ConstantFieldTool<?> tool) { |
| return !value.isDefaultForKind() || Options.TrustFinalDefaultFields.getValue(); |
| } |
| |
| @SuppressWarnings("unused") |
| protected boolean isStableField(ResolvedJavaField field, ConstantFieldTool<?> tool) { |
| if (isSyntheticEnumSwitchMap(field)) { |
| return true; |
| } |
| if (isWellKnownImplicitStableField(field)) { |
| return true; |
| } |
| if (field == stringHashField) { |
| return true; |
| } |
| return false; |
| } |
| |
| protected boolean isDefaultStableField(ResolvedJavaField field, ConstantFieldTool<?> tool) { |
| assert isStableField(field, tool); |
| if (isSyntheticEnumSwitchMap(field)) { |
| return true; |
| } |
| return false; |
| } |
| |
| @SuppressWarnings("unused") |
| protected boolean isFinalField(ResolvedJavaField field, ConstantFieldTool<?> tool) { |
| return field.isFinal(); |
| } |
| |
| protected boolean isSyntheticEnumSwitchMap(ResolvedJavaField field) { |
| if (field.isSynthetic() && field.isStatic() && isArray(field)) { |
| String name = field.getName(); |
| if (field.isFinal() && name.equals("$VALUES") || name.equals("ENUM$VALUES")) { |
| // generated int[] field for EnumClass::values() |
| return true; |
| } else if (name.startsWith("$SwitchMap$") || name.startsWith("$SWITCH_TABLE$")) { |
| // javac and ecj generate a static field in an inner class for a switch on an enum |
| // named $SwitchMap$p$k$g$EnumClass and $SWITCH_TABLE$p$k$g$EnumClass, respectively |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| private final ResolvedJavaField stringValueField; |
| private final ResolvedJavaField stringHashField; |
| |
| protected boolean isWellKnownImplicitStableField(ResolvedJavaField field) { |
| return field.equals(stringValueField); |
| } |
| } |