1/*
2 * Copyright (c) 1994, 2003, 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 sun.tools.tree;
27
28import sun.tools.java.*;
29import sun.tools.tree.*;
30import java.util.Vector;
31
32/**
33 * A local Field
34 *
35 * WARNING: The contents of this source file are not part of any
36 * supported API.  Code that depends on them does so at its own risk:
37 * they are subject to change or removal without notice.
38 */
39
40public
41class LocalMember extends MemberDefinition {
42    /**
43     * The number of the variable
44     */
45    int number = -1;
46
47    /**
48     * Some statistics
49     */
50    int readcount;
51    int writecount;
52
53    /**
54     * An indication of which block the variable comes from.
55     * Helps identify uplevel references.
56     */
57    int scopeNumber;
58
59    /**
60     * Return current nesting level, i.e., the value of 'scopeNumber'.
61     * Made public for the benefit of 'ClassDefinition.resolveName'.
62     */
63    public int getScopeNumber() {
64        return scopeNumber;
65    }
66
67    /**
68     * Used by copyInline to record the original of this copy.
69     */
70    LocalMember originalOfCopy;
71
72    /**
73     * The previous local variable, this list is used to build a nested
74     * context of local variables.
75     */
76    LocalMember prev;
77
78    /**
79     * Constructor
80     */
81    public LocalMember(long where, ClassDefinition clazz, int modifiers, Type type,
82                      Identifier name) {
83        super(where, clazz, modifiers, type, name, null, null);
84    }
85
86    /**
87     * Constructor for a block-inner class.
88     */
89    public LocalMember(ClassDefinition innerClass) {
90        super(innerClass);
91
92        // The class's "real" name is something like "foo$1$bar", but locally:
93        name = innerClass.getLocalName();
94    }
95
96    /**
97     * Constructor for a proxy to an instance or class variable.
98     */
99    LocalMember(MemberDefinition field) {
100        this(0, null, 0, field.getType(), idClass);
101        // use this random slot to store the info:
102        accessPeer = field;
103    }
104
105    /**
106     * Is this a proxy for the given field?
107     */
108    final MemberDefinition getMember() {
109        return (name == idClass) ? accessPeer : null;
110    }
111
112    /**
113     * Special checks
114     */
115    public boolean isLocal() {
116        return true;
117    }
118
119    /**
120     * Make a copy of this field, which is an argument to a method
121     * or constructor.  Arrange so that when occurrences of the field
122     * are encountered in an immediately following copyInline() operation,
123     * the expression nodes will replace the original argument by the
124     * fresh copy.
125     */
126    public LocalMember copyInline(Context ctx) {
127        LocalMember copy = new LocalMember(where, clazz, modifiers, type, name);
128        copy.readcount = this.readcount;
129        copy.writecount = this.writecount;
130
131        copy.originalOfCopy = this;
132
133        // Make a temporary link from the original.
134        // It only stays valid through the next call to copyInline().
135        // (This means that recursive inlining won't work.)
136        // To stay honest, we mark these inline copies:
137        copy.addModifiers(M_LOCAL);
138        if (this.accessPeer != null
139            && (this.accessPeer.getModifiers() & M_LOCAL) == 0) {
140            throw new CompilerError("local copyInline");
141        }
142        this.accessPeer = copy;
143
144        return copy;
145    }
146
147    /**
148     * Returns the previous result of copyInline(ctx).
149     * Must be called in the course of an Expression.copyInline()
150     * operation that immediately follows the LocalMember.copyInline().
151     * Return "this" if there is no such copy.
152     */
153    public LocalMember getCurrentInlineCopy(Context ctx) {
154        MemberDefinition accessPeer = this.accessPeer;
155        if (accessPeer != null && (accessPeer.getModifiers() & M_LOCAL) != 0) {
156            LocalMember copy = (LocalMember)accessPeer;
157            return copy;
158        }
159        return this;
160    }
161
162    /**
163     * May inline copies of all the arguments of the given method.
164     */
165    static public LocalMember[] copyArguments(Context ctx, MemberDefinition field) {
166        Vector<MemberDefinition> v = field.getArguments();
167        LocalMember res[] = new LocalMember[v.size()];
168        v.copyInto(res);
169        for (int i = 0; i < res.length; i++) {
170            res[i] = res[i].copyInline(ctx);
171        }
172        return res;
173    }
174
175    /**
176     * Call this when finished with the result of a copyArguments() call.
177     */
178    static public void doneWithArguments(Context ctx, LocalMember res[]) {
179        for (int i = 0; i < res.length; i++) {
180            if (res[i].originalOfCopy.accessPeer == res[i]) {
181                res[i].originalOfCopy.accessPeer = null;
182            }
183        }
184    }
185
186    /**
187     * Is this local variable's value stable and simple enough to be directly
188     * substituted for occurrences of the variable itself?
189     * (This decision is made by VarDeclarationStatement.inline().)
190     */
191    public boolean isInlineable(Environment env, boolean fromFinal) {
192        return (getModifiers() & M_INLINEABLE) != 0;
193    }
194
195    /**
196     * Check if used
197     */
198    public boolean isUsed() {
199        return (readcount != 0) || (writecount != 0);
200    }
201
202    // Used by class Context, only on members of MemberDefinition.available:
203    LocalMember getAccessVar() {
204        return (LocalMember)accessPeer;
205    }
206    void setAccessVar(LocalMember f) {
207        accessPeer = f;
208    }
209    // Used by class Context, only on "AccessVar" constructor args
210    MemberDefinition getAccessVarMember() {
211        return accessPeer;
212    }
213    void setAccessVarMember(MemberDefinition f) {
214        accessPeer = f;
215    }
216
217
218    /**
219     * Return value
220     */
221    public Node getValue(Environment env) {
222        return (Expression)getValue();
223    }
224
225    /**
226     * Value number for vsets, or -1 if none.
227     */
228    public int getNumber(Context ctx) {
229        return number;
230    }
231}
232