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comparison graal/GraalCompiler/src/com/sun/c1x/ir/NullCheck.java @ 2509:16b9a8b5ad39

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Renamings Runtime=>GraalRuntime and Compiler=>GraalCompiler
author Thomas Wuerthinger <thomas@wuerthinger.net>
date Wed, 27 Apr 2011 11:50:44 +0200
parents graal/Compiler/src/com/sun/c1x/ir/NullCheck.java@9ec15d6914ca
children 0f9eeb15e636
comparison
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2508:fea94949e0a2 2509:16b9a8b5ad39
1 /*
2 * Copyright (c) 2009, 2011, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package com.sun.c1x.ir;
24
25 import com.sun.c1x.debug.*;
26 import com.sun.c1x.util.*;
27 import com.sun.c1x.value.*;
28 import com.sun.cri.bytecode.*;
29 import com.sun.cri.ri.*;
30
31 /**
32 * The {@code NullCheck} class represents an explicit null check instruction.
33 *
34 * @author Ben L. Titzer
35 */
36 public final class NullCheck extends StateSplit {
37
38 Value object;
39
40 /**
41 * Constructs a new NullCheck instruction.
42 * @param obj the instruction producing the object to check against null
43 * @param stateBefore the state before executing the null check
44 */
45 public NullCheck(Value obj, FrameState stateBefore) {
46 super(obj.kind, stateBefore);
47 this.object = obj;
48 setFlag(Flag.NonNull);
49 if (object.isNonNull()) {
50 eliminateNullCheck();
51 }
52 }
53
54 /**
55 * Gets the instruction that produces the object tested against null.
56 * @return the instruction producing the object
57 */
58 public Value object() {
59 return object;
60 }
61
62 /**
63 * Checks whether this instruction can cause a trap.
64 * @return {@code true} if this instruction can cause a trap
65 */
66 @Override
67 public boolean canTrap() {
68 return needsNullCheck();
69 }
70
71 @Override
72 public void inputValuesDo(ValueClosure closure) {
73 object = closure.apply(object);
74 }
75
76 @Override
77 public void accept(ValueVisitor v) {
78 v.visitNullCheck(this);
79 }
80
81 @Override
82 public int valueNumber() {
83 return Util.hash1(Bytecodes.IFNONNULL, object);
84 }
85
86 @Override
87 public boolean valueEqual(Instruction i) {
88 if (i instanceof NullCheck) {
89 NullCheck o = (NullCheck) i;
90 return object == o.object;
91 }
92 return false;
93 }
94
95 @Override
96 public RiType declaredType() {
97 // null check does not alter the type of the object
98 return object.declaredType();
99 }
100
101 @Override
102 public RiType exactType() {
103 // null check does not alter the type of the object
104 return object.exactType();
105 }
106
107 @Override
108 public void runtimeCheckCleared() {
109 clearState();
110 }
111
112 @Override
113 public void print(LogStream out) {
114 out.print("null_check(").print(object()).print(')');
115 if (!canTrap()) {
116 out.print(" (eliminated)");
117 }
118 }
119 }