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 }