1 /*
2 * Copyright (c) 2012, 2015, 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 */
24
25 #ifndef SHARE_VM_CLASSFILE_BYTECODEASSEMBLER_HPP
26 #define SHARE_VM_CLASSFILE_BYTECODEASSEMBLER_HPP
27
28 #include "memory/allocation.hpp"
29 #include "oops/method.hpp"
30 #include "oops/symbol.hpp"
31 #include "utilities/globalDefinitions.hpp"
32 #include "utilities/growableArray.hpp"
33 #include "utilities/resourceHash.hpp"
34
35
36 /**
37 * Bytecode Assembler
38 *
39 * These classes are used to synthesize code for creating new methods from
40 * within the VM. This is only a partial implementation of an assembler;
41 * only the bytecodes that are needed by clients are implemented at this time.
42 * This is used during default method analysis to create overpass methods
43 * and add them to a call during parsing. Other uses (such as creating
44 * bridges) may come later. Any missing bytecodes can be implemented on an
45 * as-need basis.
46 */
47
48 class BytecodeBuffer : public GrowableArray<u1> {
49 public:
50 BytecodeBuffer() : GrowableArray<u1>(20) {}
51 };
52
53 // Entries in a yet-to-be-created constant pool. Limited types for now.
54 class BytecodeCPEntry VALUE_OBJ_CLASS_SPEC {
55 public:
56 enum tag {
57 ERROR_TAG,
58 UTF8,
59 KLASS,
60 STRING,
61 NAME_AND_TYPE,
62 METHODREF
63 };
64
65 u1 _tag;
66 union {
67 Symbol* utf8;
68 u2 klass;
69 u2 string;
70 struct {
71 u2 name_index;
72 u2 type_index;
73 } name_and_type;
74 struct {
75 u2 class_index;
76 u2 name_and_type_index;
77 } methodref;
78 uintptr_t hash;
79 } _u;
80
81 BytecodeCPEntry() : _tag(ERROR_TAG) { _u.hash = 0; }
82 BytecodeCPEntry(u1 tag) : _tag(tag) { _u.hash = 0; }
83
84 static BytecodeCPEntry utf8(Symbol* symbol) {
85 BytecodeCPEntry bcpe(UTF8);
86 bcpe._u.utf8 = symbol;
87 return bcpe;
88 }
89
90 static BytecodeCPEntry klass(u2 index) {
91 BytecodeCPEntry bcpe(KLASS);
92 bcpe._u.klass = index;
93 return bcpe;
94 }
95
96 static BytecodeCPEntry string(u2 index) {
97 BytecodeCPEntry bcpe(STRING);
98 bcpe._u.string = index;
99 return bcpe;
100 }
101
102 static BytecodeCPEntry name_and_type(u2 name, u2 type) {
103 BytecodeCPEntry bcpe(NAME_AND_TYPE);
104 bcpe._u.name_and_type.name_index = name;
105 bcpe._u.name_and_type.type_index = type;
106 return bcpe;
107 }
108
109 static BytecodeCPEntry methodref(u2 class_index, u2 nat) {
110 BytecodeCPEntry bcpe(METHODREF);
111 bcpe._u.methodref.class_index = class_index;
112 bcpe._u.methodref.name_and_type_index = nat;
113 return bcpe;
114 }
115
116 static bool equals(BytecodeCPEntry const& e0, BytecodeCPEntry const& e1) {
117 return e0._tag == e1._tag && e0._u.hash == e1._u.hash;
118 }
119
120 static unsigned hash(BytecodeCPEntry const& e0) {
121 return (unsigned)(e0._tag ^ e0._u.hash);
122 }
123 };
124
125 class BytecodeConstantPool : ResourceObj {
126 private:
127 typedef ResourceHashtable<BytecodeCPEntry, u2,
128 &BytecodeCPEntry::hash, &BytecodeCPEntry::equals> IndexHash;
129
130 ConstantPool* _orig;
131 GrowableArray<BytecodeCPEntry> _entries;
132 IndexHash _indices;
133
134 u2 find_or_add(BytecodeCPEntry const& bcpe);
135
136 public:
137
138 BytecodeConstantPool(ConstantPool* orig) : _orig(orig) {}
139
140 BytecodeCPEntry const& at(u2 index) const { return _entries.at(index); }
141
142 InstanceKlass* pool_holder() const {
143 return _orig->pool_holder();
144 }
145
146 u2 utf8(Symbol* sym) {
147 return find_or_add(BytecodeCPEntry::utf8(sym));
148 }
149
150 u2 klass(Symbol* class_name) {
151 return find_or_add(BytecodeCPEntry::klass(utf8(class_name)));
152 }
153
154 u2 string(Symbol* str) {
155 return find_or_add(BytecodeCPEntry::string(utf8(str)));
156 }
157
158 u2 name_and_type(Symbol* name, Symbol* sig) {
159 return find_or_add(BytecodeCPEntry::name_and_type(utf8(name), utf8(sig)));
160 }
161
162 u2 methodref(Symbol* class_name, Symbol* name, Symbol* sig) {
163 return find_or_add(BytecodeCPEntry::methodref(
164 klass(class_name), name_and_type(name, sig)));
165 }
166
167 ConstantPool* create_constant_pool(TRAPS) const;
168 };
169
170 // Partial bytecode assembler - only what we need for creating
171 // overpass methods for default methods is implemented
172 class BytecodeAssembler : StackObj {
173 private:
174 BytecodeBuffer* _code;
175 BytecodeConstantPool* _cp;
176
177 void append(u1 imm_u1);
178 void append(u2 imm_u2);
179 void append(u4 imm_u4);
180
181 void xload(u4 index, u1 quick, u1 twobyte);
182
183 public:
184 BytecodeAssembler(BytecodeBuffer* buffer, BytecodeConstantPool* cp)
185 : _code(buffer), _cp(cp) {}
186
187 void aload(u4 index);
188 void areturn();
189 void athrow();
190 void checkcast(Symbol* sym);
191 void dload(u4 index);
192 void dreturn();
193 void dup();
194 void fload(u4 index);
195 void freturn();
196 void iload(u4 index);
197 void invokespecial(Method* method);
198 void invokespecial(Symbol* cls, Symbol* name, Symbol* sig);
199 void invokevirtual(Method* method);
200 void invokevirtual(Symbol* cls, Symbol* name, Symbol* sig);
201 void ireturn();
202 void ldc(u1 index);
203 void ldc_w(u2 index);
204 void lload(u4 index);
205 void lreturn();
206 void _new(Symbol* sym);
207 void _return();
208
209 void load_string(Symbol* sym);
210 void load(BasicType bt, u4 index);
211 void _return(BasicType bt);
212 };
213
214 #endif // SHARE_VM_CLASSFILE_BYTECODEASSEMBLER_HPP