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
26 package sun.tools.tree;
27
28 import sun.tools.java.*;
29 import sun.tools.asm.Assembler;
30 import 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 */
37 public
38 class 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 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 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, new Integer(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, new Integer(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, new Integer(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, new Integer(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 }