Pool.java revision 2571:10fc81ac75b4 
1/*
2 * Copyright (c) 1999, 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
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23 * questions.
24 */
25
26package com.sun.tools.javac.jvm;
27
28import com.sun.tools.javac.code.Kinds;
29import com.sun.tools.javac.code.Symbol;
30import com.sun.tools.javac.code.Symbol.*;
31import com.sun.tools.javac.code.TypeTag;
32import com.sun.tools.javac.code.Type;
33import com.sun.tools.javac.code.Types;
34import com.sun.tools.javac.code.Types.UniqueType;
35
36import com.sun.tools.javac.util.ArrayUtils;
37import com.sun.tools.javac.util.Assert;
38import com.sun.tools.javac.util.Filter;
39import com.sun.tools.javac.util.Name;
40
41import java.util.*;
42
43/** An internal structure that corresponds to the constant pool of a classfile.
44 *
45 *  <p><b>This is NOT part of any supported API.
46 *  If you write code that depends on this, you do so at your own risk.
47 *  This code and its internal interfaces are subject to change or
48 *  deletion without notice.</b>
49 */
50public class Pool {
51
52    public static final int MAX_ENTRIES = 0xFFFF;
53    public static final int MAX_STRING_LENGTH = 0xFFFF;
54
55    /** Index of next constant to be entered.
56     */
57    int pp;
58
59    /** The initial pool buffer.
60     */
61    Object[] pool;
62
63    /** A hashtable containing all constants in the pool.
64     */
65    Map<Object,Integer> indices;
66
67    Types types;
68
69    /** Construct a pool with given number of elements and element array.
70     */
71    public Pool(int pp, Object[] pool, Types types) {
72        this.pp = pp;
73        this.pool = pool;
74        this.types = types;
75        this.indices = new HashMap<>(pool.length);
76        for (int i = 1; i < pp; i++) {
77            if (pool[i] != null) indices.put(pool[i], i);
78        }
79    }
80
81    /** Construct an empty pool.
82     */
83    public Pool(Types types) {
84        this(1, new Object[64], types);
85    }
86
87    /** Return the number of entries in the constant pool.
88     */
89    public int numEntries() {
90        return pp;
91    }
92
93    /** Remove everything from this pool.
94     */
95    public void reset() {
96        pp = 1;
97        indices.clear();
98    }
99
100    /** Place an object in the pool, unless it is already there.
101     *  If object is a symbol also enter its owner unless the owner is a
102     *  package.  Return the object's index in the pool.
103     */
104    public int put(Object value) {
105        value = makePoolValue(value);
106        Assert.check(!(value instanceof Type.TypeVar));
107        Assert.check(!(value instanceof Types.UniqueType &&
108                       ((UniqueType) value).type instanceof Type.TypeVar));
109        Integer index = indices.get(value);
110        if (index == null) {
111            index = pp;
112            indices.put(value, index);
113            pool = ArrayUtils.ensureCapacity(pool, pp);
114            pool[pp++] = value;
115            if (value instanceof Long || value instanceof Double) {
116                pool = ArrayUtils.ensureCapacity(pool, pp);
117                pool[pp++] = null;
118            }
119        }
120        return index.intValue();
121    }
122
123    Object makePoolValue(Object o) {
124        if (o instanceof DynamicMethodSymbol) {
125            return new DynamicMethod((DynamicMethodSymbol)o, types);
126        } else if (o instanceof MethodSymbol) {
127            return new Method((MethodSymbol)o, types);
128        } else if (o instanceof VarSymbol) {
129            return new Variable((VarSymbol)o, types);
130        } else if (o instanceof Type) {
131            Type t = (Type)o;
132            // ClassRefs can come from ClassSymbols or from Types.
133            // Return the symbol for these types to avoid duplicates
134            // in the constant pool
135            if (t.hasTag(TypeTag.CLASS))
136                return t.tsym;
137            else
138                return new UniqueType(t, types);
139        } else {
140            return o;
141        }
142    }
143
144    /** Return the given object's index in the pool,
145     *  or -1 if object is not in there.
146     */
147    public int get(Object o) {
148        Integer n = indices.get(o);
149        return n == null ? -1 : n.intValue();
150    }
151
152    static class Method extends DelegatedSymbol<MethodSymbol> {
153        UniqueType uniqueType;
154        Method(MethodSymbol m, Types types) {
155            super(m);
156            this.uniqueType = new UniqueType(m.type, types);
157        }
158        public boolean equals(Object any) {
159            if (!(any instanceof Method)) return false;
160            MethodSymbol o = ((Method)any).other;
161            MethodSymbol m = this.other;
162            return
163                o.name == m.name &&
164                o.owner == m.owner &&
165                ((Method)any).uniqueType.equals(uniqueType);
166        }
167        public int hashCode() {
168            MethodSymbol m = this.other;
169            return
170                m.name.hashCode() * 33 +
171                m.owner.hashCode() * 9 +
172                uniqueType.hashCode();
173        }
174    }
175
176    static class DynamicMethod extends Method {
177        public Object[] uniqueStaticArgs;
178
179        DynamicMethod(DynamicMethodSymbol m, Types types) {
180            super(m, types);
181            uniqueStaticArgs = getUniqueTypeArray(m.staticArgs, types);
182        }
183
184        @Override
185        public boolean equals(Object any) {
186            if (!super.equals(any)) return false;
187            if (!(any instanceof DynamicMethod)) return false;
188            DynamicMethodSymbol dm1 = (DynamicMethodSymbol)other;
189            DynamicMethodSymbol dm2 = (DynamicMethodSymbol)((DynamicMethod)any).other;
190            return dm1.bsm == dm2.bsm &&
191                        dm1.bsmKind == dm2.bsmKind &&
192                        Arrays.equals(uniqueStaticArgs,
193                            ((DynamicMethod)any).uniqueStaticArgs);
194        }
195
196        @Override
197        public int hashCode() {
198            int hash = super.hashCode();
199            DynamicMethodSymbol dm = (DynamicMethodSymbol)other;
200            hash += dm.bsmKind * 7 +
201                    dm.bsm.hashCode() * 11;
202            for (int i = 0; i < dm.staticArgs.length; i++) {
203                hash += (uniqueStaticArgs[i].hashCode() * 23);
204            }
205            return hash;
206        }
207
208        private Object[] getUniqueTypeArray(Object[] objects, Types types) {
209            Object[] result = new Object[objects.length];
210            for (int i = 0; i < objects.length; i++) {
211                if (objects[i] instanceof Type) {
212                    result[i] = new UniqueType((Type)objects[i], types);
213                } else {
214                    result[i] = objects[i];
215                }
216            }
217            return result;
218        }
219    }
220
221    static class Variable extends DelegatedSymbol<VarSymbol> {
222        UniqueType uniqueType;
223        Variable(VarSymbol v, Types types) {
224            super(v);
225            this.uniqueType = new UniqueType(v.type, types);
226        }
227        public boolean equals(Object any) {
228            if (!(any instanceof Variable)) return false;
229            VarSymbol o = ((Variable)any).other;
230            VarSymbol v = other;
231            return
232                o.name == v.name &&
233                o.owner == v.owner &&
234                ((Variable)any).uniqueType.equals(uniqueType);
235        }
236        public int hashCode() {
237            VarSymbol v = other;
238            return
239                v.name.hashCode() * 33 +
240                v.owner.hashCode() * 9 +
241                uniqueType.hashCode();
242        }
243    }
244
245    public static class MethodHandle {
246
247        /** Reference kind - see ClassFile */
248        int refKind;
249
250        /** Reference symbol */
251        Symbol refSym;
252
253        UniqueType uniqueType;
254
255        public MethodHandle(int refKind, Symbol refSym, Types types) {
256            this.refKind = refKind;
257            this.refSym = refSym;
258            this.uniqueType = new UniqueType(this.refSym.type, types);
259            checkConsistent();
260        }
261        public boolean equals(Object other) {
262            if (!(other instanceof MethodHandle)) return false;
263            MethodHandle mr = (MethodHandle) other;
264            if (mr.refKind != refKind)  return false;
265            Symbol o = mr.refSym;
266            return
267                o.name == refSym.name &&
268                o.owner == refSym.owner &&
269                ((MethodHandle)other).uniqueType.equals(uniqueType);
270        }
271        public int hashCode() {
272            return
273                refKind * 65 +
274                refSym.name.hashCode() * 33 +
275                refSym.owner.hashCode() * 9 +
276                uniqueType.hashCode();
277        }
278
279        /**
280         * Check consistency of reference kind and symbol (see JVMS 4.4.8)
281         */
282        @SuppressWarnings("fallthrough")
283        private void checkConsistent() {
284            boolean staticOk = false;
285            int expectedKind = -1;
286            Filter<Name> nameFilter = nonInitFilter;
287            boolean interfaceOwner = false;
288            switch (refKind) {
289                case ClassFile.REF_getStatic:
290                case ClassFile.REF_putStatic:
291                    staticOk = true;
292                case ClassFile.REF_getField:
293                case ClassFile.REF_putField:
294                    expectedKind = Kinds.VAR;
295                    break;
296                case ClassFile.REF_newInvokeSpecial:
297                    nameFilter = initFilter;
298                    expectedKind = Kinds.MTH;
299                    break;
300                case ClassFile.REF_invokeInterface:
301                    interfaceOwner = true;
302                    expectedKind = Kinds.MTH;
303                    break;
304                case ClassFile.REF_invokeStatic:
305                    interfaceOwner = true;
306                    staticOk = true;
307                case ClassFile.REF_invokeVirtual:
308                    expectedKind = Kinds.MTH;
309                    break;
310                case ClassFile.REF_invokeSpecial:
311                    interfaceOwner = true;
312                    expectedKind = Kinds.MTH;
313                    break;
314            }
315            Assert.check(!refSym.isStatic() || staticOk);
316            Assert.check(refSym.kind == expectedKind);
317            Assert.check(nameFilter.accepts(refSym.name));
318            Assert.check(!refSym.owner.isInterface() || interfaceOwner);
319        }
320        //where
321                Filter<Name> nonInitFilter = new Filter<Name>() {
322                    public boolean accepts(Name n) {
323                        return n != n.table.names.init && n != n.table.names.clinit;
324                    }
325                };
326
327                Filter<Name> initFilter = new Filter<Name>() {
328                    public boolean accepts(Name n) {
329                        return n == n.table.names.init;
330                    }
331                };
332    }
333}
334