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comparison graal/GraalCompiler/src/com/sun/c1x/ir/ExceptionHandler.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/ExceptionHandler.java@9ec15d6914ca
children 46586c77b129
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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 java.util.*;
26
27 import com.sun.c1x.lir.*;
28 import com.sun.cri.ri.*;
29
30 /**
31 * The {@code ExceptionHandler} class represents an exception handler for a Java bytecode method.
32 * There is exactly one instance of this class for every exception handler without any specific
33 * reference to an exception-throwing instruction covered by the handler. Then there is one
34 * instance per exception-throwing instruction that is used to record the frame state before
35 * execution of the instruction. The latter is used to generate exception adapter blocks
36 * (see section 3.4 of the paper <a href="http://www.usenix.org/events/vee05/full_papers/p132-wimmer.pdf">
37 * Optimized Interval Splitting in a Linear Scan Register Allocator</a>) where necessary.
38 *
39 * @author Ben L. Titzer
40 */
41 public final class ExceptionHandler {
42
43 public static final List<ExceptionHandler> ZERO_HANDLERS = Collections.emptyList();
44
45 public final RiExceptionHandler handler;
46 private BlockBegin entryBlock;
47 private LIRList entryCode;
48 private int entryCodeOffset;
49 private int phiOperand;
50 private int scopeCount;
51 private int lirOpId;
52
53 public ExceptionHandler(RiExceptionHandler handler) {
54 this.handler = handler;
55 this.entryCodeOffset = -1;
56 this.phiOperand = -1;
57 this.scopeCount = -1;
58 this.lirOpId = -1;
59 }
60
61 public ExceptionHandler(ExceptionHandler other) {
62 this.handler = other.handler;
63 this.entryBlock = other.entryBlock;
64 this.entryCode = other.entryCode;
65 this.entryCodeOffset = other.entryCodeOffset;
66 this.phiOperand = other.phiOperand;
67 this.scopeCount = other.scopeCount;
68 this.lirOpId = other.lirOpId;
69 }
70
71 @Override
72 public String toString() {
73 return "XHandler(Block=" + entryBlock.blockID + ") " + handler;
74 }
75
76 /**
77 * Gets the compiler interface object that describes this exception handler,
78 * including the bytecode ranges.
79 * @return the compiler interface exception handler
80 */
81 public RiExceptionHandler handler() {
82 return handler;
83 }
84
85 /**
86 * Gets the bytecode index of the handler (catch block).
87 * @return the bytecode index of the handler
88 */
89 public int handlerBCI() {
90 return handler.handlerBCI();
91 }
92
93 /**
94 * Utility method to check if this exception handler covers the specified bytecode index.
95 * @param bci the bytecode index to check
96 * @return {@code true} if this exception handler covers the specified bytecode
97 */
98 public boolean covers(int bci) {
99 return handler.startBCI() <= bci && bci < handler.endBCI();
100 }
101
102 /**
103 * Gets the entry block for this exception handler.
104 * @return the entry block
105 */
106 public BlockBegin entryBlock() {
107 return entryBlock;
108 }
109
110 /**
111 * Gets the PC offset of the handler entrypoint, which is used by
112 * the runtime to forward exception points to their catch sites.
113 * @return the pc offset of the handler entrypoint
114 */
115 public int entryCodeOffset() {
116 return entryCodeOffset;
117 }
118
119 public int phiOperand() {
120 return phiOperand;
121 }
122
123 public int scopeCount() {
124 return scopeCount;
125 }
126
127 public void setEntryBlock(BlockBegin entry) {
128 entryBlock = entry;
129 }
130
131 public void setEntryCodeOffset(int pco) {
132 entryCodeOffset = pco;
133 }
134
135 public void setPhiOperand(int phi) {
136 phiOperand = phi;
137 }
138
139 public void setScopeCount(int count) {
140 scopeCount = count;
141 }
142
143 public boolean isCatchAll() {
144 return handler.catchTypeCPI() == 0;
145 }
146
147 public static boolean couldCatch(List<ExceptionHandler> exceptionHandlers, RiType klass, boolean typeIsExact) {
148 // the type is unknown so be conservative
149 if (!klass.isResolved()) {
150 return true;
151 }
152
153 for (int i = 0; i < exceptionHandlers.size(); i++) {
154 ExceptionHandler handler = exceptionHandlers.get(i);
155 if (handler.isCatchAll()) {
156 // catch of ANY
157 return true;
158 }
159 RiType handlerKlass = handler.handler.catchType();
160 // if it's unknown it might be catchable
161 if (!handlerKlass.isResolved()) {
162 return true;
163 }
164 // if the throw type is definitely a subtype of the catch type
165 // then it can be caught.
166 if (klass.isSubtypeOf(handlerKlass)) {
167 return true;
168 }
169 if (!typeIsExact) {
170 // If the type isn't exactly known then it can also be caught by
171 // catch statements where the inexact type is a subtype of the
172 // catch type.
173 // given: foo extends bar extends Exception
174 // throw bar can be caught by catch foo, catch bar, and catch
175 // Exception, however it can't be caught by any handlers without
176 // bar in its type hierarchy.
177 if (handlerKlass.isSubtypeOf(klass)) {
178 return true;
179 }
180 }
181 }
182 return false;
183 }
184
185 public int lirOpId() {
186 return lirOpId;
187 }
188
189 public LIRList entryCode() {
190 return entryCode;
191 }
192
193 public void setLirOpId(int throwingOpId) {
194 lirOpId = throwingOpId;
195 }
196
197 public void setEntryCode(LIRList entryCode) {
198 this.entryCode = entryCode;
199
200 }
201 }