1 /*
2 * Copyright (c) 1997, 2014, 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_RUNTIME_RELOCATOR_HPP
26 #define SHARE_VM_RUNTIME_RELOCATOR_HPP
27
28 #include "interpreter/bytecodes.hpp"
29 #include "oops/method.hpp"
30 #include "utilities/bytes.hpp"
31
32 // This code has been converted from the 1.1E java virtual machine
33 // Thanks to the JavaTopics group for using the code
34
35 class ChangeItem;
36
37 // Callback object for code relocations
38 class RelocatorListener : public StackObj {
39 public:
40 RelocatorListener() {};
41 virtual void relocated(int bci, int delta, int new_method_size) = 0;
42 };
43
44
45 class Relocator : public ResourceObj {
46 public:
47 Relocator(methodHandle method, RelocatorListener* listener);
48 methodHandle insert_space_at(int bci, int space, u_char inst_buffer[], TRAPS);
49
50 // Callbacks from ChangeItem's
51 bool handle_code_changes();
52 bool handle_widen (int bci, int new_ilen, u_char inst_buffer[]); // handles general instructions
53 void push_jump_widen (int bci, int delta, int new_delta); // pushes jumps
54 bool handle_jump_widen (int bci, int delta); // handles jumps
55 bool handle_switch_pad (int bci, int old_pad, bool is_lookup_switch); // handles table and lookup switches
56
57 private:
58 unsigned char* _code_array;
59 int _code_array_length;
60 int _code_length;
61 unsigned char* _compressed_line_number_table;
62 int _compressed_line_number_table_size;
63 methodHandle _method;
64 u_char _overwrite[3]; // stores overwritten bytes for shrunken instructions
65
66 GrowableArray<ChangeItem*>* _changes;
67
68 unsigned char* code_array() const { return _code_array; }
69 void set_code_array(unsigned char* array) { _code_array = array; }
70
71 int code_length() const { return _code_length; }
72 void set_code_length(int length) { _code_length = length; }
73
74 int code_array_length() const { return _code_array_length; }
75 void set_code_array_length(int length) { _code_array_length = length; }
76
77 unsigned char* compressed_line_number_table() const { return _compressed_line_number_table; }
78 void set_compressed_line_number_table(unsigned char* table) { _compressed_line_number_table = table; }
79
80 int compressed_line_number_table_size() const { return _compressed_line_number_table_size; }
81 void set_compressed_line_number_table_size(int size) { _compressed_line_number_table_size = size; }
82
83 methodHandle method() const { return _method; }
84 void set_method(methodHandle method) { _method = method; }
85
86 // This will return a raw bytecode, which is possibly rewritten.
87 Bytecodes::Code code_at(int bci) const { return (Bytecodes::Code) code_array()[bci]; }
88 void code_at_put(int bci, Bytecodes::Code code) { code_array()[bci] = (char) code; }
89
90 // get and set signed integers in the code_array
91 inline int int_at(int bci) const { return Bytes::get_Java_u4(&code_array()[bci]); }
92 inline void int_at_put(int bci, int value) { Bytes::put_Java_u4(&code_array()[bci], value); }
93
94 // get and set signed shorts in the code_array
95 inline short short_at(int bci) const { return (short)Bytes::get_Java_u2(&code_array()[bci]); }
96 inline void short_at_put(int bci, short value) { Bytes::put_Java_u2((address) &code_array()[bci], value); }
97
98 // get the address of in the code_array
99 inline char* addr_at(int bci) const { return (char*) &code_array()[bci]; }
100
101 int instruction_length_at(int bci) { return Bytecodes::length_at(NULL, code_array() + bci); }
102
103 // Helper methods
104 int align(int n) const { return (n+3) & ~3; }
105 int code_slop_pct() const { return 25; }
106 bool is_opcode_lookupswitch(Bytecodes::Code bc);
107
108 // basic relocation methods
109 bool relocate_code (int bci, int ilen, int delta);
110 void change_jumps (int break_bci, int delta);
111 void change_jump (int bci, int offset, bool is_short, int break_bci, int delta);
112 void adjust_exception_table(int bci, int delta);
113 void adjust_line_no_table (int bci, int delta);
114 void adjust_local_var_table(int bci, int delta);
115 void adjust_stack_map_table(int bci, int delta);
116 int get_orig_switch_pad (int bci, bool is_lookup_switch);
117 int rc_instr_len (int bci);
118 bool expand_code_array (int delta);
119
120 // Callback support
121 RelocatorListener *_listener;
122 void notify(int bci, int delta, int new_code_length) {
123 if (_listener != NULL)
124 _listener->relocated(bci, delta, new_code_length);
125 }
126 };
127
128 #endif // SHARE_VM_RUNTIME_RELOCATOR_HPP