1 /*
2 * Copyright (c) 2009, 2014, 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 jdk.vm.ci.meta;
24
25 /**
26 * Represents the runtime representation of the constant pool that is used by the compiler when
27 * parsing bytecode. Provides methods to look up a constant pool entry without performing
28 * resolution. They are used during compilation.
29 */
30 public interface ConstantPool {
31
32 /**
33 * Returns the number of entries the constant pool.
34 *
35 * @return number of entries in the constant pool
36 */
37 int length();
38
39 /**
40 * Ensures that the type referenced by the specified constant pool entry is loaded and
41 * initialized. This can be used to compile time resolve a type. It works for field, method, or
42 * type constant pool entries.
43 *
44 * @param cpi the index of the constant pool entry that references the type
45 * @param opcode the opcode of the instruction that references the type
46 */
47 void loadReferencedType(int cpi, int opcode);
48
49 /**
50 * Looks up a reference to a field. If {@code opcode} is non-negative, then resolution checks
51 * specific to the bytecode it denotes are performed if the field is already resolved. Checks
52 * for some bytecodes require the method that contains the bytecode to be specified. Should
53 * any of these checks fail, an unresolved field reference is returned.
54 *
55 * @param cpi the constant pool index
56 * @param opcode the opcode of the instruction for which the lookup is being performed or
57 * {@code -1}
58 * @param method the method for which the lookup is being performed
59 * @return a reference to the field at {@code cpi} in this pool
60 * @throws ClassFormatError if the entry at {@code cpi} is not a field
61 */
62 JavaField lookupField(int cpi, ResolvedJavaMethod method, int opcode);
63
64 /**
65 * Looks up a reference to a method. If {@code opcode} is non-negative, then resolution checks
66 * specific to the bytecode it denotes are performed if the method is already resolved. Should
67 * any of these checks fail, an unresolved method reference is returned.
68 *
69 * @param cpi the constant pool index
70 * @param opcode the opcode of the instruction for which the lookup is being performed or
71 * {@code -1}
72 * @return a reference to the method at {@code cpi} in this pool
73 * @throws ClassFormatError if the entry at {@code cpi} is not a method
74 */
75 JavaMethod lookupMethod(int cpi, int opcode);
76
77 /**
78 * Looks up a reference to a type. If {@code opcode} is non-negative, then resolution checks
79 * specific to the bytecode it denotes are performed if the type is already resolved. Should any
80 * of these checks fail, an unresolved type reference is returned.
81 *
82 * @param cpi the constant pool index
83 * @param opcode the opcode of the instruction for which the lookup is being performed or
84 * {@code -1}
85 * @return a reference to the compiler interface type
86 */
87 JavaType lookupType(int cpi, int opcode);
88
89 /**
90 * Looks up an Utf8 string.
91 *
92 * @param cpi the constant pool index
93 * @return the Utf8 string at index {@code cpi} in this constant pool
94 */
95 String lookupUtf8(int cpi);
96
97 /**
98 * Looks up a method signature.
99 *
100 * @param cpi the constant pool index
101 * @return the method signature at index {@code cpi} in this constant pool
102 */
103 Signature lookupSignature(int cpi);
104
105 /**
106 * Looks up a constant at the specified index.
107 *
108 * @param cpi the constant pool index
109 * @return the {@code Constant} or {@code JavaType} instance representing the constant pool
110 * entry
111 */
112 Object lookupConstant(int cpi);
113
114 /**
115 * Looks up the appendix at the specified index.
116 *
117 * @param cpi the constant pool index
118 * @param opcode the opcode of the instruction for which the lookup is being performed or
119 * {@code -1}
120 * @return the appendix if it exists and is resolved or {@code null}
121 */
122 JavaConstant lookupAppendix(int cpi, int opcode);
123 }