relocator.hpp revision 0:a61af66fc99e 
1/*
2 * Copyright 1997-2004 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25// This code has been converted from the 1.1E java virtual machine
26// Thanks to the JavaTopics group for using the code
27
28class ChangeItem;
29
30// Callback object for code relocations
31class RelocatorListener : public StackObj {
32 public:
33  RelocatorListener() {};
34  virtual void relocated(int bci, int delta, int new_method_size) = 0;
35};
36
37
38class Relocator : public ResourceObj {
39 public:
40  Relocator(methodHandle method, RelocatorListener* listener);
41  methodHandle insert_space_at(int bci, int space, u_char inst_buffer[], TRAPS);
42
43  // Callbacks from ChangeItem's
44  bool handle_code_changes();
45  bool handle_widen       (int bci, int new_ilen, u_char inst_buffer[]);  // handles general instructions
46  void push_jump_widen  (int bci, int delta, int new_delta);    // pushes jumps
47  bool handle_jump_widen  (int bci, int delta);     // handles jumps
48  bool handle_switch_pad  (int bci, int old_pad, bool is_lookup_switch); // handles table and lookup switches
49
50 private:
51  unsigned char* _code_array;
52  int            _code_array_length;
53  int            _code_length;
54  unsigned char* _compressed_line_number_table;
55  int            _compressed_line_number_table_size;
56  methodHandle   _method;
57  u_char         _overwrite[3];             // stores overwritten bytes for shrunken instructions
58
59  GrowableArray<ChangeItem*>* _changes;
60
61  unsigned char* code_array() const         { return _code_array; }
62  void set_code_array(unsigned char* array) { _code_array = array; }
63
64  int code_length() const                   { return _code_length; }
65  void set_code_length(int length)          { _code_length = length; }
66
67  int code_array_length() const             { return _code_array_length; }
68  void set_code_array_length(int length)    { _code_array_length = length; }
69
70  unsigned char* compressed_line_number_table() const         { return _compressed_line_number_table; }
71  void set_compressed_line_number_table(unsigned char* table) { _compressed_line_number_table = table; }
72
73  int compressed_line_number_table_size() const               { return _compressed_line_number_table_size; }
74  void set_compressed_line_number_table_size(int size)        { _compressed_line_number_table_size = size; }
75
76  methodHandle method() const               { return _method; }
77  void set_method(methodHandle method)      { _method = method; }
78
79  // This will return a raw bytecode, which is possibly rewritten.
80  Bytecodes::Code code_at(int bci) const          { return (Bytecodes::Code) code_array()[bci]; }
81  void code_at_put(int bci, Bytecodes::Code code) { code_array()[bci] = (char) code; }
82
83  // get and set signed integers in the code_array
84  inline int   int_at(int bci) const               { return Bytes::get_Java_u4(&code_array()[bci]); }
85  inline void  int_at_put(int bci, int value)      { Bytes::put_Java_u4(&code_array()[bci], value); }
86
87  // get and set signed shorts in the code_array
88  inline short short_at(int bci) const            { return (short)Bytes::get_Java_u2(&code_array()[bci]); }
89  inline void  short_at_put(int bci, short value) { Bytes::put_Java_u2((address) &code_array()[bci], value); }
90
91  // get the address of in the code_array
92  inline char* addr_at(int bci) const             { return (char*) &code_array()[bci]; }
93
94  int  instruction_length_at(int bci)             { return Bytecodes::length_at(code_array() + bci); }
95
96  // Helper methods
97  int  align(int n) const                          { return (n+3) & ~3; }
98  int  code_slop_pct() const                       { return 25; }
99  bool is_opcode_lookupswitch(Bytecodes::Code bc);
100
101  // basic relocation methods
102  bool relocate_code         (int bci, int ilen, int delta);
103  void change_jumps          (int break_bci, int delta);
104  void change_jump           (int bci, int offset, bool is_short, int break_bci, int delta);
105  void adjust_exception_table(int bci, int delta);
106  void adjust_line_no_table  (int bci, int delta);
107  void adjust_local_var_table(int bci, int delta);
108  int  get_orig_switch_pad   (int bci, bool is_lookup_switch);
109  int  rc_instr_len          (int bci);
110  bool expand_code_array     (int delta);
111
112  // Callback support
113  RelocatorListener *_listener;
114  void notify(int bci, int delta, int new_code_length) {
115    if (_listener != NULL)
116      _listener->relocated(bci, delta, new_code_length);
117  }
118};
119