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.io.PrintStream;
31 import java.util.Hashtable;
32
33 /**
34 * WARNING: The contents of this source file are not part of any
35 * supported API. Code that depends on them does so at its own risk:
36 * they are subject to change or removal without notice.
37 */
38 public abstract
39 class AssignOpExpression extends BinaryAssignExpression {
40 protected Type itype; // Type of intermediate result, before assigning
41 final int NOINC = Integer.MAX_VALUE;
42
43 protected FieldUpdater updater = null; // Used also in 'AssignAddExpression'.
44
45 /**
46 * Constructor
47 */
48 public AssignOpExpression(int op, long where, Expression left, Expression right) {
49 super(op, where, left, right);
50 }
51
52 /**
53 * Select the type
54 *
55 */
56
57 final void selectType(Environment env, Context ctx, int tm) {
58 Type rtype = null; // special conversion type for RHS
59 switch(op) {
60 case ASGADD:
61 if (left.type == Type.tString) {
62 if (right.type == Type.tVoid) {
63 // The type of the right hand side can be
64 // anything except void. Fix for 4119864.
65 env.error(where, "incompatible.type",
66 opNames[op], Type.tVoid, Type.tString);
67 type = Type.tError;
68 } else {
69 type = itype = Type.tString;
70 }
71 return;
72 }
73 /* Fall through */
74 case ASGDIV: case ASGMUL: case ASGSUB: case ASGREM:
75 if ((tm & TM_DOUBLE) != 0) {
76 itype = Type.tDouble;
77 } else if ((tm & TM_FLOAT) != 0) {
78 itype = Type.tFloat;
79 } else if ((tm & TM_LONG) != 0) {
80 itype = Type.tLong;
81 } else {
82 itype = Type.tInt;
83 }
84 break;
85
86 case ASGBITAND: case ASGBITOR: case ASGBITXOR:
87 if ((tm & TM_BOOLEAN) != 0) {
88 itype = Type.tBoolean;
89 } else if ((tm & TM_LONG) != 0) {
90 itype = Type.tLong;
91 } else {
92 itype = Type.tInt;
93 }
94 break;
95
96 case ASGLSHIFT: case ASGRSHIFT: case ASGURSHIFT:
97 rtype = Type.tInt;
98
99 // Fix for bug 4134459.
100 // We allow any integral type (even long) to
101 // be the right hand side of a shift operation.
102 if (right.type.inMask(TM_INTEGER)) {
103 right = new ConvertExpression(where, Type.tInt, right);
104 }
105 // The intermediate type of the expression is the
106 // type of the left hand side after undergoing
107 // unary (not binary) type promotion. We ignore
108 // tm -- it contains information about both left
109 // and right hand sides -- and we compute the
110 // type only from the type of the lhs.
111 if (left.type == Type.tLong) {
112 itype = Type.tLong;
113 } else {
114 itype = Type.tInt;
115 }
116
117 break;
118
119 default:
120 throw new CompilerError("Bad assignOp type: " + op);
121 }
122 if (rtype == null) {
123 rtype = itype;
124 }
125 right = convert(env, ctx, rtype, right);
126 // The result is always the type of the left operand.
127
128 type = left.type;
129 }
130
131
132 /**
133 * Get the increment, return NOINC if an increment is not possible
134 */
135 int getIncrement() {
136 if ((left.op == IDENT) && type.isType(TC_INT) && (right.op == INTVAL))
137 if ((op == ASGADD) || (op == ASGSUB))
138 if (((IdentifierExpression)left).field.isLocal()) {
139 int val = ((IntExpression)right).value;
140 if (op == ASGSUB)
141 val = -val;
142 if (val == (short)val)
143 return val;
144 }
145 return NOINC;
146 }
147
148
149 /**
150 * Check an assignment expression
151 */
152 public Vset checkValue(Environment env, Context ctx, Vset vset, Hashtable exp) {
153 vset = left.checkAssignOp(env, ctx, vset, exp, this);
154 vset = right.checkValue(env, ctx, vset, exp);
155 int tm = left.type.getTypeMask() | right.type.getTypeMask();
156 if ((tm & TM_ERROR) != 0) {
157 return vset;
158 }
159 selectType(env, ctx, tm);
160 if (!type.isType(TC_ERROR)) {
161 convert(env, ctx, itype, left);
162 }
163 updater = left.getUpdater(env, ctx); // Must be called after 'checkAssignOp'.
164 return vset;
165 }
166
167 /**
168 * Inline
169 */
170 public Expression inlineValue(Environment env, Context ctx) {
171 // Why not inlineLHS? But that does not work.
172 left = left.inlineValue(env, ctx);
173 right = right.inlineValue(env, ctx);
174 if (updater != null) {
175 updater = updater.inline(env, ctx);
176 }
177 return this;
178 }
179
180 /**
181 * Create a copy of the expression for method inlining
182 */
183 public Expression copyInline(Context ctx) {
184 AssignOpExpression e = (AssignOpExpression)clone();
185 e.left = left.copyInline(ctx);
186 e.right = right.copyInline(ctx);
187 if (updater != null) {
188 e.updater = updater.copyInline(ctx);
189 }
190 return e;
191 }
192
193 /**
194 * The cost of inlining this statement
195 */
196 public int costInline(int thresh, Environment env, Context ctx) {
197 /*----------*
198 return (getIncrement() != NOINC)
199 ? 2
200 : (3 + super.costInline(thresh, env, ctx));
201 *----------*/
202 if (updater == null) {
203 return (getIncrement() != NOINC)
204 // Increment variable in place. Count 3 bytes for 'iinc'.
205 ? 3
206 // Cost of rhs expression + cost of lhs expression + cost
207 // of load/op/store instructions. E.g.: iload = 1 or 2,
208 // istore = 1 or 2, iadd = 1. Cost could be higher if
209 // getfield/putfield or conversions needed, lower if rhs is
210 // a small constant. Costs are highly approximate.
211 : right.costInline(thresh, env, ctx) +
212 left.costInline(thresh, env, ctx) + 4;
213 } else {
214 // Cost of rhs expression + (2 * cost of access method call) +
215 // cost of operator. Does not account for cost of conversions,
216 // or duplications in value-needed context.
217 return right.costInline(thresh, env, ctx) +
218 updater.costInline(thresh, env, ctx, true) + 1;
219 }
220 }
221
222 /**
223 * Code
224 */
225 void code(Environment env, Context ctx, Assembler asm, boolean valNeeded) {
226
227 // Handle cases in which a '+=' or '-=' operator can be optimized using
228 // the 'iinc' instruction. See also 'IncDecExpression.codeIncDec'.
229 // The 'iinc' instruction cannot be used if an access method call is required.
230 int val = getIncrement();
231 if (val != NOINC && updater == null) {
232 int v = ((LocalMember)((IdentifierExpression)left).field).number;
233 int[] operands = { v, val };
234 asm.add(where, opc_iinc, operands);
235 if (valNeeded) {
236 left.codeValue(env, ctx, asm);
237 }
238 return;
239 }
240
241 if (updater == null) {
242 // Field is directly accessible.
243 int depth = left.codeLValue(env, ctx, asm);
244 codeDup(env, ctx, asm, depth, 0);
245 left.codeLoad(env, ctx, asm);
246 codeConversion(env, ctx, asm, left.type, itype);
247 right.codeValue(env, ctx, asm);
248 codeOperation(env, ctx, asm);
249 codeConversion(env, ctx, asm, itype, type);
250 if (valNeeded) {
251 codeDup(env, ctx, asm, type.stackSize(), depth);
252 }
253 left.codeStore(env, ctx, asm);
254 } else {
255 // Must use access methods.
256 updater.startUpdate(env, ctx, asm, false);
257 codeConversion(env, ctx, asm, left.type, itype);
258 right.codeValue(env, ctx, asm);
259 codeOperation(env, ctx, asm);
260 codeConversion(env, ctx, asm, itype, type);
261 updater.finishUpdate(env, ctx, asm, valNeeded);
262 }
263 }
264
265 public void codeValue(Environment env, Context ctx, Assembler asm) {
266 code(env, ctx, asm, true);
267 }
268 public void code(Environment env, Context ctx, Assembler asm) {
269 code(env, ctx, asm, false);
270 }
271
272 /**
273 * Print
274 */
275 public void print(PrintStream out) {
276 out.print("(" + opNames[op] + " ");
277 left.print(out);
278 out.print(" ");
279 right.print(out);
280 out.print(")");
281 }
282 }