1 /*
2 * Copyright (c) 1997, 2010, 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.
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23 */
24
25 #ifndef SHARE_VM_INTERPRETER_BYTECODESTREAM_HPP
26 #define SHARE_VM_INTERPRETER_BYTECODESTREAM_HPP
27
28 #include "interpreter/bytecode.hpp"
29 #include "memory/allocation.hpp"
30 #include "oops/methodOop.hpp"
31 #ifdef TARGET_ARCH_x86
32 # include "bytes_x86.hpp"
33 #endif
34 #ifdef TARGET_ARCH_sparc
35 # include "bytes_sparc.hpp"
36 #endif
37 #ifdef TARGET_ARCH_zero
38 # include "bytes_zero.hpp"
39 #endif
40
41 // A BytecodeStream is used for fast iteration over the bytecodes
42 // of a methodOop.
43 //
44 // Usage:
45 //
46 // BytecodeStream s(method);
47 // Bytecodes::Code c;
48 // while ((c = s.next()) >= 0) {
49 // ...
50 // }
51
52 // A RawBytecodeStream is a simple version of BytecodeStream.
53 // It is used ONLY when we know the bytecodes haven't been rewritten
54 // yet, such as in the rewriter or the verifier.
55
56 // Here is the common base class for both RawBytecodeStream and BytecodeStream:
57 class BaseBytecodeStream: StackObj {
58 protected:
59 // stream buffer
60 methodHandle _method; // read from method directly
61
62 // reading position
63 int _bci; // bci if current bytecode
64 int _next_bci; // bci of next bytecode
65 int _end_bci; // bci after the current iteration interval
66
67 // last bytecode read
68 Bytecodes::Code _raw_code;
69 bool _is_wide;
70 bool _is_raw; // false in 'cooked' BytecodeStream
71
72 // Construction
73 BaseBytecodeStream(methodHandle method) : _method(method) {
74 set_interval(0, _method->code_size());
75 _is_raw = false;
76 }
77
78 public:
79 // Iteration control
80 void set_interval(int beg_bci, int end_bci) {
81 // iterate over the interval [beg_bci, end_bci)
82 assert(0 <= beg_bci && beg_bci <= method()->code_size(), "illegal beg_bci");
83 assert(0 <= end_bci && end_bci <= method()->code_size(), "illegal end_bci");
84 // setup of iteration pointers
85 _bci = beg_bci;
86 _next_bci = beg_bci;
87 _end_bci = end_bci;
88 }
89 void set_start (int beg_bci) {
90 set_interval(beg_bci, _method->code_size());
91 }
92
93 bool is_raw() const { return _is_raw; }
94
95 // Stream attributes
96 methodHandle method() const { return _method; }
97
98 int bci() const { return _bci; }
99 int next_bci() const { return _next_bci; }
100 int end_bci() const { return _end_bci; }
101
102 Bytecodes::Code raw_code() const { return _raw_code; }
103 bool is_wide() const { return _is_wide; }
104 int instruction_size() const { return (_next_bci - _bci); }
105 bool is_last_bytecode() const { return _next_bci >= _end_bci; }
106
107 address bcp() const { return method()->code_base() + _bci; }
108 Bytecode* bytecode() const { return Bytecode_at(bcp()); }
109
110 // State changes
111 void set_next_bci(int bci) { assert(0 <= bci && bci <= method()->code_size(), "illegal bci"); _next_bci = bci; }
112
113 // Bytecode-specific attributes
114 int dest() const { return bci() + bytecode()->get_offset_s2(raw_code()); }
115 int dest_w() const { return bci() + bytecode()->get_offset_s4(raw_code()); }
116
117 // One-byte indices.
118 int get_index_u1() const { assert_raw_index_size(1); return *(jubyte*)(bcp()+1); }
119
120 protected:
121 void assert_raw_index_size(int size) const NOT_DEBUG_RETURN;
122 void assert_raw_stream(bool want_raw) const NOT_DEBUG_RETURN;
123 };
124
125 class RawBytecodeStream: public BaseBytecodeStream {
126 public:
127 // Construction
128 RawBytecodeStream(methodHandle method) : BaseBytecodeStream(method) {
129 _is_raw = true;
130 }
131
132 public:
133 // Iteration
134 // Use raw_next() rather than next() for faster method reference
135 Bytecodes::Code raw_next() {
136 Bytecodes::Code code;
137 // set reading position
138 _bci = _next_bci;
139 assert(!is_last_bytecode(), "caller should check is_last_bytecode()");
140
141 address bcp = this->bcp();
142 code = Bytecodes::code_or_bp_at(bcp);
143
144 // set next bytecode position
145 int l = Bytecodes::length_for(code);
146 if (l > 0 && (_bci + l) <= _end_bci) {
147 assert(code != Bytecodes::_wide && code != Bytecodes::_tableswitch
148 && code != Bytecodes::_lookupswitch, "can't be special bytecode");
149 _is_wide = false;
150 _next_bci += l;
151 _raw_code = code;
152 return code;
153 } else {
154 return raw_next_special(code);
155 }
156 }
157 Bytecodes::Code raw_next_special(Bytecodes::Code code);
158
159 // Unsigned indices, widening, with no swapping of bytes
160 int get_index() const { return (is_wide()) ? get_index_u2_raw(bcp() + 2) : get_index_u1(); }
161 // Get an unsigned 2-byte index, with no swapping of bytes.
162 int get_index_u2() const { assert(!is_wide(), ""); return get_index_u2_raw(bcp() + 1); }
163
164 private:
165 int get_index_u2_raw(address p) const {
166 assert_raw_index_size(2); assert_raw_stream(true);
167 return Bytes::get_Java_u2(p);
168 }
169 };
170
171 // In BytecodeStream, non-java bytecodes will be translated into the
172 // corresponding java bytecodes.
173
174 class BytecodeStream: public BaseBytecodeStream {
175 Bytecodes::Code _code;
176
177 public:
178 // Construction
179 BytecodeStream(methodHandle method) : BaseBytecodeStream(method) { }
180
181 // Iteration
182 Bytecodes::Code next() {
183 Bytecodes::Code raw_code, code;
184 // set reading position
185 _bci = _next_bci;
186 if (is_last_bytecode()) {
187 // indicate end of bytecode stream
188 raw_code = code = Bytecodes::_illegal;
189 } else {
190 // get bytecode
191 address bcp = this->bcp();
192 raw_code = Bytecodes::code_at(bcp);
193 code = Bytecodes::java_code(raw_code);
194 // set next bytecode position
195 //
196 // note that we cannot advance before having the
197 // tty bytecode otherwise the stepping is wrong!
198 // (carefull: length_for(...) must be used first!)
199 int l = Bytecodes::length_for(code);
200 if (l == 0) l = Bytecodes::length_at(bcp);
201 _next_bci += l;
202 assert(_bci < _next_bci, "length must be > 0");
203 // set attributes
204 _is_wide = false;
205 // check for special (uncommon) cases
206 if (code == Bytecodes::_wide) {
207 raw_code = (Bytecodes::Code)bcp[1];
208 code = raw_code; // wide BCs are always Java-normal
209 _is_wide = true;
210 }
211 assert(Bytecodes::is_java_code(code), "sanity check");
212 }
213 _raw_code = raw_code;
214 _code = code;
215 return _code;
216 }
217
218 bool is_active_breakpoint() const { return Bytecodes::is_active_breakpoint_at(bcp()); }
219 Bytecodes::Code code() const { return _code; }
220
221 // Unsigned indices, widening
222 int get_index() const { return is_wide() ? bytecode()->get_index_u2(raw_code(), true) : get_index_u1(); }
223 // Get an unsigned 2-byte index, swapping the bytes if necessary.
224 int get_index_u2() const { assert_raw_stream(false);
225 return bytecode()->get_index_u2(raw_code(), false); }
226 // Get an unsigned 2-byte index in native order.
227 int get_index_u2_cpcache() const { assert_raw_stream(false);
228 return bytecode()->get_index_u2_cpcache(raw_code()); }
229 int get_index_u4() const { assert_raw_stream(false);
230 return bytecode()->get_index_u4(raw_code()); }
231 bool has_index_u4() const { return bytecode()->has_index_u4(raw_code()); }
232 };
233
234 #endif // SHARE_VM_INTERPRETER_BYTECODESTREAM_HPP