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Java > Open Source Codes > jbet > LocalAccess


1 /*
2  * JBET - Java Binary Enhancement Tool
3  * Copyright (c) 2003 Networks Associates Technology, Inc.
4  *
5  * This software was developed under DARPA/SPAWAR contract
6  * N66001-00-C-8602 "SPMA" as part of the
7  * DARPA OASIS research program.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  * notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in the
16  * documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30
31 package jbet;
32
33 /* An abstraction for the local variables. An implementation that uses ordinary JVM locals is
34    available as JvmLocals.
35  
36    @author Andrew Reisse
37 */
38
39 public abstract class LocalAccess
40 {
41     /* initialze all locals with a default value */
42     abstract public void initlocals (Snippit out, int min);
43
44     /* same affect as [aildf]load lvt */
45     abstract public void load (Snippit out, int lvt, Type t);
46
47     /* same affect as [aildf]store lvt */
48     abstract public void store (Snippit out, int lvt, Type t);
49
50     /* A store that is saving stack elements. */
51     public void storeStack (Snippit out, int lvt, Type t) { store (out, lvt, t); }
52
53     /* Allocate a JVM local, that is to be used as input USE
54        of type T.
55
56        @param use Input node
57        @param t type of value
58        @return a JVM local number
59     */
60     abstract public int alloc (Node.var use);
61
62
63     /* Allocate a JVM local, that is to be used as temporary storage
64        or method arguments.
65
66        @param lo Temporary number
67        @param t type of value
68        @return a JVM local number
69     */
70     abstract public int alloc (int lo, Type t);
71
72     /* Allocate a one-time temporary local.
73        @param t type of value
74        @return a jvm local number
75     */
76     abstract public int alloc (Type t);
77
78     /* Free the local use allocated by alloc(use). */
79     abstract public void free (Node.var use);
80
81     /* Reset all local allocation */
82     abstract public void freeall ();
83
84     /* how many JVM locals are used by these locals. */
85     abstract public int numJvmLocals ();
86 }
87
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