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.asm.Assembler;
30import java.util.Hashtable;
31
32/**
33 * WARNING: The contents of this source file are not part of any
34 * supported API.  Code that depends on them does so at its own risk:
35 * they are subject to change or removal without notice.
36 */
37public
38class IncDecExpression extends UnaryExpression {
39
40    private FieldUpdater updater = null;
41
42    /**
43     * Constructor
44     */
45    public IncDecExpression(int op, long where, Expression right) {
46        super(op, where, right.type, right);
47    }
48
49    /**
50     * Check an increment or decrement expression
51     */
52    public Vset checkValue(Environment env, Context ctx, Vset vset, Hashtable<Object, Object> exp) {
53        vset = right.checkAssignOp(env, ctx, vset, exp, this);
54        if (right.type.inMask(TM_NUMBER)) {
55            type = right.type;
56        } else {
57            if (!right.type.isType(TC_ERROR)) {
58                env.error(where, "invalid.arg.type", right.type, opNames[op]);
59            }
60            type = Type.tError;
61        }
62        updater = right.getUpdater(env, ctx);  // Must be called after 'checkAssignOp'.
63        return vset;
64    }
65
66    /**
67     * Check void expression
68     */
69    public Vset check(Environment env, Context ctx, Vset vset, Hashtable<Object, Object> exp) {
70        return checkValue(env, ctx, vset, exp);
71    }
72
73    /**
74     * Inline
75     */
76    public Expression inline(Environment env, Context ctx) {
77        return inlineValue(env, ctx);
78    }
79    public Expression inlineValue(Environment env, Context ctx) {
80        // Why not inlineLHS?  But that does not work.
81        right = right.inlineValue(env, ctx);
82        if (updater != null) {
83            updater = updater.inline(env, ctx);
84        }
85        return this;
86    }
87
88    public int costInline(int thresh, Environment env, Context ctx) {
89        if (updater == null) {
90            if ((right.op == IDENT) && type.isType(TC_INT) &&
91                (((IdentifierExpression)right).field.isLocal())) {
92                // Increment variable in place.  Count 3 bytes for 'iinc'.
93                return 3;
94            }
95            // Cost to load lhs reference, fetch local, increment, and store.
96            // Load/store cost will be higher if variable is a field.  Note that
97            // costs are highly approximate. See 'AssignOpExpression.costInline'
98            // Does not account for cost of conversions,or duplications in
99            // value-needed context..
100            return right.costInline(thresh, env, ctx) + 4;
101        } else {
102            // Cost of two access method calls (get/set) + cost of increment.
103            return updater.costInline(thresh, env, ctx, true) + 1;
104        }
105    }
106
107
108    /**
109     * Code
110     */
111
112    private void codeIncDecOp(Assembler asm, boolean inc) {
113        switch (type.getTypeCode()) {
114          case TC_BYTE:
115            asm.add(where, opc_ldc, 1);
116            asm.add(where, inc ? opc_iadd : opc_isub);
117            asm.add(where, opc_i2b);
118            break;
119          case TC_SHORT:
120            asm.add(where, opc_ldc, 1);
121            asm.add(where, inc ? opc_iadd : opc_isub);
122            asm.add(where, opc_i2s);
123            break;
124          case TC_CHAR:
125            asm.add(where, opc_ldc, 1);
126            asm.add(where, inc ? opc_iadd : opc_isub);
127            asm.add(where, opc_i2c);
128            break;
129          case TC_INT:
130            asm.add(where, opc_ldc, 1);
131            asm.add(where, inc ? opc_iadd : opc_isub);
132            break;
133          case TC_LONG:
134            asm.add(where, opc_ldc2_w, 1L);
135            asm.add(where, inc ? opc_ladd : opc_lsub);
136            break;
137          case TC_FLOAT:
138            asm.add(where, opc_ldc, new Float(1));
139            asm.add(where, inc ? opc_fadd : opc_fsub);
140            break;
141          case TC_DOUBLE:
142            asm.add(where, opc_ldc2_w, new Double(1));
143            asm.add(where, inc ? opc_dadd : opc_dsub);
144            break;
145          default:
146            throw new CompilerError("invalid type");
147        }
148    }
149
150    void codeIncDec(Environment env, Context ctx, Assembler asm, boolean inc, boolean prefix, boolean valNeeded) {
151
152        // The 'iinc' instruction cannot be used if an access method call is required.
153        if ((right.op == IDENT) && type.isType(TC_INT) &&
154            (((IdentifierExpression)right).field.isLocal()) && updater == null) {
155            if (valNeeded && !prefix) {
156                right.codeLoad(env, ctx, asm);
157            }
158            int v = ((LocalMember)((IdentifierExpression)right).field).number;
159            int[] operands = { v, inc ? 1 : -1 };
160            asm.add(where, opc_iinc, operands);
161            if (valNeeded && prefix) {
162                right.codeLoad(env, ctx, asm);
163            }
164            return;
165
166        }
167
168        if (updater == null) {
169            // Field is directly accessible.
170            int depth = right.codeLValue(env, ctx, asm);
171            codeDup(env, ctx, asm, depth, 0);
172            right.codeLoad(env, ctx, asm);
173            if (valNeeded && !prefix) {
174                codeDup(env, ctx, asm, type.stackSize(), depth);
175            }
176            codeIncDecOp(asm, inc);
177            if (valNeeded && prefix) {
178                codeDup(env, ctx, asm, type.stackSize(), depth);
179            }
180            right.codeStore(env, ctx, asm);
181        } else {
182            // Must use access methods.
183            updater.startUpdate(env, ctx, asm, (valNeeded && !prefix));
184            codeIncDecOp(asm, inc);
185            updater.finishUpdate(env, ctx, asm, (valNeeded && prefix));
186        }
187    }
188
189}
190