bytecodeStream.hpp revision 3602:da91efe96a93 
1/*
2 * Copyright (c) 1997, 2012, 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
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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/method.hpp"
31#include "runtime/handles.inline.hpp"
32#ifdef TARGET_ARCH_x86
33# include "bytes_x86.hpp"
34#endif
35#ifdef TARGET_ARCH_sparc
36# include "bytes_sparc.hpp"
37#endif
38#ifdef TARGET_ARCH_zero
39# include "bytes_zero.hpp"
40#endif
41#ifdef TARGET_ARCH_arm
42# include "bytes_arm.hpp"
43#endif
44#ifdef TARGET_ARCH_ppc
45# include "bytes_ppc.hpp"
46#endif
47
48// A BytecodeStream is used for fast iteration over the bytecodes
49// of a Method*.
50//
51// Usage:
52//
53// BytecodeStream s(method);
54// Bytecodes::Code c;
55// while ((c = s.next()) >= 0) {
56//   ...
57// }
58
59// A RawBytecodeStream is a simple version of BytecodeStream.
60// It is used ONLY when we know the bytecodes haven't been rewritten
61// yet, such as in the rewriter or the verifier.
62
63// Here is the common base class for both RawBytecodeStream and BytecodeStream:
64class BaseBytecodeStream: StackObj {
65 protected:
66  // stream buffer
67  methodHandle    _method;                       // read from method directly
68
69  // reading position
70  int             _bci;                          // bci if current bytecode
71  int             _next_bci;                     // bci of next bytecode
72  int             _end_bci;                      // bci after the current iteration interval
73
74  // last bytecode read
75  Bytecodes::Code _raw_code;
76  bool            _is_wide;
77  bool            _is_raw;                       // false in 'cooked' BytecodeStream
78
79  // Construction
80  BaseBytecodeStream(methodHandle method) : _method(method) {
81    set_interval(0, _method->code_size());
82    _is_raw = false;
83  }
84
85 public:
86  // Iteration control
87  void set_interval(int beg_bci, int end_bci) {
88    // iterate over the interval [beg_bci, end_bci)
89    assert(0 <= beg_bci && beg_bci <= method()->code_size(), "illegal beg_bci");
90    assert(0 <= end_bci && end_bci <= method()->code_size(), "illegal end_bci");
91    // setup of iteration pointers
92    _bci      = beg_bci;
93    _next_bci = beg_bci;
94    _end_bci  = end_bci;
95  }
96  void set_start   (int beg_bci) {
97    set_interval(beg_bci, _method->code_size());
98  }
99
100  bool is_raw() const { return _is_raw; }
101
102  // Stream attributes
103  methodHandle    method() const                 { return _method; }
104
105  int             bci() const                    { return _bci; }
106  int             next_bci() const               { return _next_bci; }
107  int             end_bci() const                { return _end_bci; }
108
109  Bytecodes::Code raw_code() const               { return _raw_code; }
110  bool            is_wide() const                { return _is_wide; }
111  int             instruction_size() const       { return (_next_bci - _bci); }
112  bool            is_last_bytecode() const       { return _next_bci >= _end_bci; }
113
114  address         bcp() const                    { return method()->code_base() + _bci; }
115  Bytecode        bytecode() const               { return Bytecode(_method(), bcp()); }
116
117  // State changes
118  void            set_next_bci(int bci)          { assert(0 <= bci && bci <= method()->code_size(), "illegal bci"); _next_bci = bci; }
119
120  // Bytecode-specific attributes
121  int             dest() const                   { return bci() + bytecode().get_offset_s2(raw_code()); }
122  int             dest_w() const                 { return bci() + bytecode().get_offset_s4(raw_code()); }
123
124  // One-byte indices.
125  int             get_index_u1() const           { assert_raw_index_size(1); return *(jubyte*)(bcp()+1); }
126
127 protected:
128  void assert_raw_index_size(int size) const NOT_DEBUG_RETURN;
129  void assert_raw_stream(bool want_raw) const NOT_DEBUG_RETURN;
130};
131
132class RawBytecodeStream: public BaseBytecodeStream {
133 public:
134  // Construction
135  RawBytecodeStream(methodHandle method) : BaseBytecodeStream(method) {
136    _is_raw = true;
137  }
138
139 public:
140  // Iteration
141  // Use raw_next() rather than next() for faster method reference
142  Bytecodes::Code raw_next() {
143    Bytecodes::Code code;
144    // set reading position
145    _bci = _next_bci;
146    assert(!is_last_bytecode(), "caller should check is_last_bytecode()");
147
148    address bcp = this->bcp();
149    code        = Bytecodes::code_or_bp_at(bcp);
150
151    // set next bytecode position
152    int l = Bytecodes::length_for(code);
153    if (l > 0 && (_bci + l) <= _end_bci) {
154      assert(code != Bytecodes::_wide && code != Bytecodes::_tableswitch
155             && code != Bytecodes::_lookupswitch, "can't be special bytecode");
156      _is_wide = false;
157      _next_bci += l;
158      _raw_code = code;
159      return code;
160    } else {
161      return raw_next_special(code);
162    }
163  }
164  Bytecodes::Code raw_next_special(Bytecodes::Code code);
165
166  // Unsigned indices, widening, with no swapping of bytes
167  int             get_index() const          { return (is_wide()) ? get_index_u2_raw(bcp() + 2) : get_index_u1(); }
168  // Get an unsigned 2-byte index, with no swapping of bytes.
169  int             get_index_u2() const       { assert(!is_wide(), ""); return get_index_u2_raw(bcp() + 1);  }
170
171 private:
172  int get_index_u2_raw(address p) const {
173    assert_raw_index_size(2); assert_raw_stream(true);
174    return Bytes::get_Java_u2(p);
175  }
176};
177
178// In BytecodeStream, non-java bytecodes will be translated into the
179// corresponding java bytecodes.
180
181class BytecodeStream: public BaseBytecodeStream {
182  Bytecodes::Code _code;
183
184 public:
185  // Construction
186  BytecodeStream(methodHandle method) : BaseBytecodeStream(method) { }
187
188  // Iteration
189  Bytecodes::Code next() {
190    Bytecodes::Code raw_code, code;
191    // set reading position
192    _bci = _next_bci;
193    if (is_last_bytecode()) {
194      // indicate end of bytecode stream
195      raw_code = code = Bytecodes::_illegal;
196    } else {
197      // get bytecode
198      address bcp = this->bcp();
199      raw_code = Bytecodes::code_at(_method(), bcp);
200      code = Bytecodes::java_code(raw_code);
201      // set next bytecode position
202      //
203      // note that we cannot advance before having the
204      // tty bytecode otherwise the stepping is wrong!
205      // (carefull: length_for(...) must be used first!)
206      int l = Bytecodes::length_for(code);
207      if (l == 0) l = Bytecodes::length_at(_method(), bcp);
208      _next_bci  += l;
209      assert(_bci < _next_bci, "length must be > 0");
210      // set attributes
211      _is_wide      = false;
212      // check for special (uncommon) cases
213      if (code == Bytecodes::_wide) {
214        raw_code = (Bytecodes::Code)bcp[1];
215        code = raw_code;  // wide BCs are always Java-normal
216        _is_wide = true;
217      }
218      assert(Bytecodes::is_java_code(code), "sanity check");
219    }
220    _raw_code = raw_code;
221    _code = code;
222    return _code;
223  }
224
225  bool            is_active_breakpoint() const   { return Bytecodes::is_active_breakpoint_at(bcp()); }
226  Bytecodes::Code code() const                   { return _code; }
227
228  // Unsigned indices, widening
229  int             get_index() const              { return is_wide() ? bytecode().get_index_u2(raw_code(), true) : get_index_u1(); }
230  // Get an unsigned 2-byte index, swapping the bytes if necessary.
231  int             get_index_u2() const           { assert_raw_stream(false);
232                                                   return bytecode().get_index_u2(raw_code(), false); }
233  // Get an unsigned 2-byte index in native order.
234  int             get_index_u2_cpcache() const   { assert_raw_stream(false);
235                                                   return bytecode().get_index_u2_cpcache(raw_code()); }
236  int             get_index_u4() const           { assert_raw_stream(false);
237                                                   return bytecode().get_index_u4(raw_code()); }
238  bool            has_index_u4() const           { return bytecode().has_index_u4(raw_code()); }
239};
240
241#endif // SHARE_VM_INTERPRETER_BYTECODESTREAM_HPP
242