1 /*
2 * Copyright (c) 2003, 2006, 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 class StackMapReader;
26
27 // StackMapTable class is the StackMap table used by type checker
28 class StackMapTable : public StackObj {
29 private:
30 // Logically, the _frame_count (as well as many fields in the StackFrame)
31 // should be a u2, but if we defined the variable as that type it will
32 // be difficult to detect/recover from overflow or underflow conditions.
33 // Widening the type and making it signed will help detect these.
34 int32_t _code_length;
35 int32_t _frame_count; // Stackmap frame count
36 StackMapFrame** _frame_array;
37
38 public:
39 StackMapTable(StackMapReader* reader, StackMapFrame* init_frame,
40 u2 max_locals, u2 max_stack,
41 char* code_data, int code_len, TRAPS);
42
43 inline int32_t get_frame_count() const { return _frame_count; }
44 inline int get_offset(int index) const {
45 return _frame_array[index]->offset();
46 }
47
48 // Match and/or update current_frame to the frame in stackmap table with
49 // specified offset. Return true if the two frames match.
50 bool match_stackmap(
51 StackMapFrame* current_frame, int32_t offset,
52 bool match, bool update, TRAPS) const;
53 // Match and/or update current_frame to the frame in stackmap table with
54 // specified offset and frame index. Return true if the two frames match.
55 bool match_stackmap(
56 StackMapFrame* current_frame, int32_t offset, int32_t frame_index,
57 bool match, bool update, TRAPS) const;
58
59 // Check jump instructions. Make sure there are no uninitialized
60 // instances on backward branch.
61 void check_jump_target(StackMapFrame* frame, int32_t target, TRAPS) const;
62
63 // The following methods are only used inside this class.
64
65 // Returns the frame array index where the frame with offset is stored.
66 int get_index_from_offset(int32_t offset) const;
67
68 // Make sure that there's no uninitialized object exist on backward branch.
69 void check_new_object(
70 const StackMapFrame* frame, int32_t target, TRAPS) const;
71
72 // Debugging
73 void print() const PRODUCT_RETURN;
74 };
75
76 class StackMapStream : StackObj {
77 private:
78 typeArrayHandle _data;
79 int _index;
80 public:
81 StackMapStream(typeArrayHandle ah)
82 : _data(ah), _index(0) {
83 }
84 u1 get_u1(TRAPS) {
85 if (_data == NULL || _index >= _data->length()) {
86 stackmap_format_error("access beyond the end of attribute", CHECK_0);
87 }
88 return _data->byte_at(_index++);
89 }
90 u2 get_u2(TRAPS) {
91 if (_data == NULL || _index >= _data->length() - 1) {
92 stackmap_format_error("access beyond the end of attribute", CHECK_0);
93 }
94 u2 res = Bytes::get_Java_u2((u1*)_data->byte_at_addr(_index));
95 _index += 2;
96 return res;
97 }
98 bool at_end() {
99 return (_data == NULL) || (_index == _data->length());
100 }
101 static void stackmap_format_error(const char* msg, TRAPS);
102 };
103
104 class StackMapReader : StackObj {
105 private:
106 // information about the class and method
107 constantPoolHandle _cp;
108 ClassVerifier* _verifier;
109 StackMapStream* _stream;
110 char* _code_data;
111 int32_t _code_length;
112
113 // information get from the attribute
114 int32_t _frame_count; // frame count
115
116 int32_t chop(VerificationType* locals, int32_t length, int32_t chops);
117 VerificationType parse_verification_type(u1* flags, TRAPS);
118 void check_verification_type_array_size(
119 int32_t size, int32_t max_size, TRAPS) {
120 if (size < 0 || size > max_size) {
121 // Since this error could be caused someone rewriting the method
122 // but not knowing to update the stackmap data, we call the the
123 // verifier's error method, which may not throw an exception and
124 // failover to the old verifier instead.
125 _verifier->class_format_error(
126 "StackMapTable format error: bad type array size");
127 }
128 }
129
130 enum {
131 SAME_LOCALS_1_STACK_ITEM_EXTENDED = 247,
132 SAME_EXTENDED = 251,
133 FULL = 255
134 };
135
136 public:
137 // Constructor
138 StackMapReader(ClassVerifier* v, StackMapStream* stream, char* code_data,
139 int32_t code_len, TRAPS) :
140 _verifier(v), _stream(stream),
141 _code_data(code_data), _code_length(code_len) {
142 methodHandle m = v->method();
143 if (m->has_stackmap_table()) {
144 _cp = constantPoolHandle(THREAD, m->constants());
145 _frame_count = _stream->get_u2(CHECK);
146 } else {
147 // There's no stackmap table present. Frame count and size are 0.
148 _frame_count = 0;
149 }
150 }
151
152 inline int32_t get_frame_count() const { return _frame_count; }
153 StackMapFrame* next(StackMapFrame* pre_frame, bool first,
154 u2 max_locals, u2 max_stack, TRAPS);
155
156 void check_end(TRAPS) {
157 if (!_stream->at_end()) {
158 StackMapStream::stackmap_format_error("wrong attribute size", CHECK);
159 }
160 }
161 };