bytecodeStream.hpp revision 2073:b92c45f2bc75 
1/*
2 * Copyright (c) 1997, 2011, 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.
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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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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#ifdef TARGET_ARCH_arm
41# include "bytes_arm.hpp"
42#endif
43#ifdef TARGET_ARCH_ppc
44# include "bytes_ppc.hpp"
45#endif
46
47// A BytecodeStream is used for fast iteration over the bytecodes
48// of a methodOop.
49//
50// Usage:
51//
52// BytecodeStream s(method);
53// Bytecodes::Code c;
54// while ((c = s.next()) >= 0) {
55//   ...
56// }
57
58// A RawBytecodeStream is a simple version of BytecodeStream.
59// It is used ONLY when we know the bytecodes haven't been rewritten
60// yet, such as in the rewriter or the verifier.
61
62// Here is the common base class for both RawBytecodeStream and BytecodeStream:
63class BaseBytecodeStream: StackObj {
64 protected:
65  // stream buffer
66  methodHandle    _method;                       // read from method directly
67
68  // reading position
69  int             _bci;                          // bci if current bytecode
70  int             _next_bci;                     // bci of next bytecode
71  int             _end_bci;                      // bci after the current iteration interval
72
73  // last bytecode read
74  Bytecodes::Code _raw_code;
75  bool            _is_wide;
76  bool            _is_raw;                       // false in 'cooked' BytecodeStream
77
78  // Construction
79  BaseBytecodeStream(methodHandle method) : _method(method) {
80    set_interval(0, _method->code_size());
81    _is_raw = false;
82  }
83
84 public:
85  // Iteration control
86  void set_interval(int beg_bci, int end_bci) {
87    // iterate over the interval [beg_bci, end_bci)
88    assert(0 <= beg_bci && beg_bci <= method()->code_size(), "illegal beg_bci");
89    assert(0 <= end_bci && end_bci <= method()->code_size(), "illegal end_bci");
90    // setup of iteration pointers
91    _bci      = beg_bci;
92    _next_bci = beg_bci;
93    _end_bci  = end_bci;
94  }
95  void set_start   (int beg_bci) {
96    set_interval(beg_bci, _method->code_size());
97  }
98
99  bool is_raw() const { return _is_raw; }
100
101  // Stream attributes
102  methodHandle    method() const                 { return _method; }
103
104  int             bci() const                    { return _bci; }
105  int             next_bci() const               { return _next_bci; }
106  int             end_bci() const                { return _end_bci; }
107
108  Bytecodes::Code raw_code() const               { return _raw_code; }
109  bool            is_wide() const                { return _is_wide; }
110  int             instruction_size() const       { return (_next_bci - _bci); }
111  bool            is_last_bytecode() const       { return _next_bci >= _end_bci; }
112
113  address         bcp() const                    { return method()->code_base() + _bci; }
114  Bytecode        bytecode() const               { return Bytecode(_method(), bcp()); }
115
116  // State changes
117  void            set_next_bci(int bci)          { assert(0 <= bci && bci <= method()->code_size(), "illegal bci"); _next_bci = bci; }
118
119  // Bytecode-specific attributes
120  int             dest() const                   { return bci() + bytecode().get_offset_s2(raw_code()); }
121  int             dest_w() const                 { return bci() + bytecode().get_offset_s4(raw_code()); }
122
123  // One-byte indices.
124  int             get_index_u1() const           { assert_raw_index_size(1); return *(jubyte*)(bcp()+1); }
125
126 protected:
127  void assert_raw_index_size(int size) const NOT_DEBUG_RETURN;
128  void assert_raw_stream(bool want_raw) const NOT_DEBUG_RETURN;
129};
130
131class RawBytecodeStream: public BaseBytecodeStream {
132 public:
133  // Construction
134  RawBytecodeStream(methodHandle method) : BaseBytecodeStream(method) {
135    _is_raw = true;
136  }
137
138 public:
139  // Iteration
140  // Use raw_next() rather than next() for faster method reference
141  Bytecodes::Code raw_next() {
142    Bytecodes::Code code;
143    // set reading position
144    _bci = _next_bci;
145    assert(!is_last_bytecode(), "caller should check is_last_bytecode()");
146
147    address bcp = this->bcp();
148    code        = Bytecodes::code_or_bp_at(bcp);
149
150    // set next bytecode position
151    int l = Bytecodes::length_for(code);
152    if (l > 0 && (_bci + l) <= _end_bci) {
153      assert(code != Bytecodes::_wide && code != Bytecodes::_tableswitch
154             && code != Bytecodes::_lookupswitch, "can't be special bytecode");
155      _is_wide = false;
156      _next_bci += l;
157      _raw_code = code;
158      return code;
159    } else {
160      return raw_next_special(code);
161    }
162  }
163  Bytecodes::Code raw_next_special(Bytecodes::Code code);
164
165  // Unsigned indices, widening, with no swapping of bytes
166  int             get_index() const          { return (is_wide()) ? get_index_u2_raw(bcp() + 2) : get_index_u1(); }
167  // Get an unsigned 2-byte index, with no swapping of bytes.
168  int             get_index_u2() const       { assert(!is_wide(), ""); return get_index_u2_raw(bcp() + 1);  }
169
170 private:
171  int get_index_u2_raw(address p) const {
172    assert_raw_index_size(2); assert_raw_stream(true);
173    return Bytes::get_Java_u2(p);
174  }
175};
176
177// In BytecodeStream, non-java bytecodes will be translated into the
178// corresponding java bytecodes.
179
180class BytecodeStream: public BaseBytecodeStream {
181  Bytecodes::Code _code;
182
183 public:
184  // Construction
185  BytecodeStream(methodHandle method) : BaseBytecodeStream(method) { }
186
187  // Iteration
188  Bytecodes::Code next() {
189    Bytecodes::Code raw_code, code;
190    // set reading position
191    _bci = _next_bci;
192    if (is_last_bytecode()) {
193      // indicate end of bytecode stream
194      raw_code = code = Bytecodes::_illegal;
195    } else {
196      // get bytecode
197      address bcp = this->bcp();
198      raw_code = Bytecodes::code_at(_method(), bcp);
199      code = Bytecodes::java_code(raw_code);
200      // set next bytecode position
201      //
202      // note that we cannot advance before having the
203      // tty bytecode otherwise the stepping is wrong!
204      // (carefull: length_for(...) must be used first!)
205      int l = Bytecodes::length_for(code);
206      if (l == 0) l = Bytecodes::length_at(_method(), bcp);
207      _next_bci  += l;
208      assert(_bci < _next_bci, "length must be > 0");
209      // set attributes
210      _is_wide      = false;
211      // check for special (uncommon) cases
212      if (code == Bytecodes::_wide) {
213        raw_code = (Bytecodes::Code)bcp[1];
214        code = raw_code;  // wide BCs are always Java-normal
215        _is_wide = true;
216      }
217      assert(Bytecodes::is_java_code(code), "sanity check");
218    }
219    _raw_code = raw_code;
220    _code = code;
221    return _code;
222  }
223
224  bool            is_active_breakpoint() const   { return Bytecodes::is_active_breakpoint_at(bcp()); }
225  Bytecodes::Code code() const                   { return _code; }
226
227  // Unsigned indices, widening
228  int             get_index() const              { return is_wide() ? bytecode().get_index_u2(raw_code(), true) : get_index_u1(); }
229  // Get an unsigned 2-byte index, swapping the bytes if necessary.
230  int             get_index_u2() const           { assert_raw_stream(false);
231                                                   return bytecode().get_index_u2(raw_code(), false); }
232  // Get an unsigned 2-byte index in native order.
233  int             get_index_u2_cpcache() const   { assert_raw_stream(false);
234                                                   return bytecode().get_index_u2_cpcache(raw_code()); }
235  int             get_index_u4() const           { assert_raw_stream(false);
236                                                   return bytecode().get_index_u4(raw_code()); }
237  bool            has_index_u4() const           { return bytecode().has_index_u4(raw_code()); }
238};
239
240#endif // SHARE_VM_INTERPRETER_BYTECODESTREAM_HPP
241