ObjectType.java revision 1068:34ef988d5959 
1/*
2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package jdk.nashorn.internal.codegen.types;
27
28import static jdk.internal.org.objectweb.asm.Opcodes.ACONST_NULL;
29import static jdk.internal.org.objectweb.asm.Opcodes.ALOAD;
30import static jdk.internal.org.objectweb.asm.Opcodes.ARETURN;
31import static jdk.internal.org.objectweb.asm.Opcodes.ASTORE;
32import static jdk.internal.org.objectweb.asm.Opcodes.CHECKCAST;
33import static jdk.internal.org.objectweb.asm.Opcodes.GETSTATIC;
34import static jdk.nashorn.internal.codegen.CompilerConstants.className;
35import static jdk.nashorn.internal.codegen.CompilerConstants.typeDescriptor;
36
37import java.lang.invoke.MethodHandle;
38import jdk.internal.org.objectweb.asm.Handle;
39import jdk.internal.org.objectweb.asm.MethodVisitor;
40import jdk.nashorn.internal.codegen.CompilerConstants;
41import jdk.nashorn.internal.runtime.JSType;
42import jdk.nashorn.internal.runtime.ScriptRuntime;
43import jdk.nashorn.internal.runtime.Undefined;
44
45/**
46 * Type class: OBJECT This is the object type, used for all object types. It can
47 * contain a class that is a more specialized object
48 */
49class ObjectType extends Type {
50    private static final long serialVersionUID = 1L;
51
52    protected ObjectType() {
53        this(Object.class);
54    }
55
56    protected ObjectType(final Class<?> clazz) {
57        super("object",
58                clazz,
59                clazz == Object.class ? Type.MAX_WEIGHT : 10,
60                1);
61    }
62
63    @Override
64    public String toString() {
65        return "object" + (getTypeClass() != Object.class ? "<type=" + getTypeClass().getSimpleName() + '>' : "");
66    }
67
68    @Override
69    public String getShortDescriptor() {
70        return getTypeClass() == Object.class ? "Object" : getTypeClass().getSimpleName();
71    }
72
73    @Override
74    public Type add(final MethodVisitor method, final int programPoint) {
75        invokestatic(method, ScriptRuntime.ADD);
76        return Type.OBJECT;
77    }
78
79    @Override
80    public Type load(final MethodVisitor method, final int slot) {
81        assert slot != -1;
82        method.visitVarInsn(ALOAD, slot);
83        return this;
84    }
85
86    @Override
87    public void store(final MethodVisitor method, final int slot) {
88        assert slot != -1;
89        method.visitVarInsn(ASTORE, slot);
90    }
91
92    @Override
93    public Type loadUndefined(final MethodVisitor method) {
94        method.visitFieldInsn(GETSTATIC, className(ScriptRuntime.class), "UNDEFINED", typeDescriptor(Undefined.class));
95        return UNDEFINED;
96    }
97
98    @Override
99    public Type loadForcedInitializer(final MethodVisitor method) {
100        method.visitInsn(ACONST_NULL);
101        // TODO: do we need a special type for null, e.g. Type.NULL? It should be assignable to any other object type
102        // without a checkast in convert.
103        return OBJECT;
104    }
105
106    @Override
107    public Type loadEmpty(final MethodVisitor method) {
108        method.visitFieldInsn(GETSTATIC, className(ScriptRuntime.class), "EMPTY", typeDescriptor(Undefined.class));
109        return UNDEFINED;
110    }
111
112    @Override
113    public Type ldc(final MethodVisitor method, final Object c) {
114        if (c == null) {
115            method.visitInsn(ACONST_NULL);
116        } else if (c instanceof Undefined) {
117            return loadUndefined(method);
118        } else if (c instanceof String) {
119            method.visitLdcInsn(c);
120            return STRING;
121        } else if (c instanceof Handle) {
122            method.visitLdcInsn(c);
123            return Type.typeFor(MethodHandle.class);
124        } else {
125            throw new UnsupportedOperationException("implementation missing for class " + c.getClass() + " value=" + c);
126        }
127
128        return Type.OBJECT;
129    }
130
131    @Override
132    public Type convert(final MethodVisitor method, final Type to) {
133        final boolean toString = to.isString();
134        if (!toString) {
135            if (to.isArray()) {
136                final Type elemType = ((ArrayType)to).getElementType();
137
138                //note that if this an array, things won't work. see {link @ArrayType} subclass.
139                //we also have the unpleasant case of NativeArray which looks like an Object, but is
140                //an array to the type system. This is treated specially at the known load points
141
142                if (elemType.isString()) {
143                    method.visitTypeInsn(CHECKCAST, CompilerConstants.className(String[].class));
144                } else if (elemType.isNumber()) {
145                    method.visitTypeInsn(CHECKCAST, CompilerConstants.className(double[].class));
146                } else if (elemType.isLong()) {
147                    method.visitTypeInsn(CHECKCAST, CompilerConstants.className(long[].class));
148                } else if (elemType.isInteger()) {
149                    method.visitTypeInsn(CHECKCAST, CompilerConstants.className(int[].class));
150                } else {
151                    method.visitTypeInsn(CHECKCAST, CompilerConstants.className(Object[].class));
152                }
153                return to;
154            } else if (to.isObject()) {
155                final Class<?> toClass = to.getTypeClass();
156                if(!toClass.isAssignableFrom(getTypeClass())) {
157                    method.visitTypeInsn(CHECKCAST, CompilerConstants.className(toClass));
158                }
159                return to;
160            }
161        } else if (isString()) {
162            return to;
163        }
164
165        if (to.isInteger()) {
166            invokestatic(method, JSType.TO_INT32);
167        } else if (to.isNumber()) {
168            invokestatic(method, JSType.TO_NUMBER);
169        } else if (to.isLong()) {
170            invokestatic(method, JSType.TO_LONG);
171        } else if (to.isBoolean()) {
172            invokestatic(method, JSType.TO_BOOLEAN);
173        } else if (to.isString()) {
174            invokestatic(method, JSType.TO_PRIMITIVE_TO_STRING);
175        } else if (to.isCharSequence()) {
176            invokestatic(method, JSType.TO_PRIMITIVE_TO_CHARSEQUENCE);
177        } else {
178            throw new UnsupportedOperationException("Illegal conversion " + this + " -> " + to + " " + isString() + " " + toString);
179        }
180
181        return to;
182    }
183
184    @Override
185    public void _return(final MethodVisitor method) {
186        method.visitInsn(ARETURN);
187    }
188
189    @Override
190    public char getBytecodeStackType() {
191        return 'A';
192    }
193}
194