1 /*
2 * Copyright (c) 2003, 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_CLASSFILE_STACKMAPTABLE_HPP
26 #define SHARE_VM_CLASSFILE_STACKMAPTABLE_HPP
27
28 #include "classfile/stackMapFrame.hpp"
29 #include "classfile/verifier.hpp"
30 #include "memory/allocation.hpp"
31 #include "oops/constantPool.hpp"
32 #include "oops/method.hpp"
33 #include "utilities/bytes.hpp"
34 #include "utilities/globalDefinitions.hpp"
35
36 class StackMapReader;
37
38 // StackMapTable class is the StackMap table used by type checker
39 class StackMapTable : public StackObj {
40 private:
41 // Logically, the _frame_count (as well as many fields in the StackFrame)
42 // should be a u2, but if we defined the variable as that type it will
43 // be difficult to detect/recover from overflow or underflow conditions.
44 // Widening the type and making it signed will help detect these.
45 int32_t _code_length;
46 int32_t _frame_count; // Stackmap frame count
47 StackMapFrame** _frame_array;
48
49 public:
50 StackMapTable(StackMapReader* reader, StackMapFrame* init_frame,
51 u2 max_locals, u2 max_stack,
52 char* code_data, int code_len, TRAPS);
53
54 inline int32_t get_frame_count() const { return _frame_count; }
55 inline int get_offset(int index) const {
56 return _frame_array[index]->offset();
57 }
58
59 // Match and/or update current_frame to the frame in stackmap table with
60 // specified offset. Return true if the two frames match.
61 bool match_stackmap(
62 StackMapFrame* current_frame, int32_t offset,
63 bool match, bool update, bool handler, ErrorContext* ctx, TRAPS) const;
64 // Match and/or update current_frame to the frame in stackmap table with
65 // specified offset and frame index. Return true if the two frames match.
66 bool match_stackmap(
67 StackMapFrame* current_frame, int32_t offset, int32_t frame_index,
68 bool match, bool update, bool handler, ErrorContext* ctx, TRAPS) const;
69
70 // Check jump instructions. Make sure there are no uninitialized
71 // instances on backward branch.
72 void check_jump_target(StackMapFrame* frame, int32_t target, TRAPS) const;
73
74 // The following methods are only used inside this class.
75
76 // Returns the frame array index where the frame with offset is stored.
77 int get_index_from_offset(int32_t offset) const;
78
79 // Make sure that there's no uninitialized object exist on backward branch.
80 void check_new_object(
81 const StackMapFrame* frame, int32_t target, TRAPS) const;
82
83 void print_on(outputStream* str) const;
84 };
85
86 class StackMapStream : StackObj {
87 private:
88 Array<u1>* _data;
89 int _index;
90 public:
91 StackMapStream(Array<u1>* ah)
92 : _data(ah), _index(0) {
93 }
94 u1 get_u1(TRAPS) {
95 if (_data == NULL || _index >= _data->length()) {
96 stackmap_format_error("access beyond the end of attribute", CHECK_0);
97 }
98 return _data->at(_index++);
99 }
100 u2 get_u2(TRAPS) {
101 if (_data == NULL || _index >= _data->length() - 1) {
102 stackmap_format_error("access beyond the end of attribute", CHECK_0);
103 }
104 u2 res = Bytes::get_Java_u2(_data->adr_at(_index));
105 _index += 2;
106 return res;
107 }
108 bool at_end() {
109 return (_data == NULL) || (_index == _data->length());
110 }
111 static void stackmap_format_error(const char* msg, TRAPS);
112 };
113
114 class StackMapReader : StackObj {
115 private:
116 // information about the class and method
117 constantPoolHandle _cp;
118 ClassVerifier* _verifier;
119 StackMapStream* _stream;
120 char* _code_data;
121 int32_t _code_length;
122
123 // information get from the attribute
124 int32_t _frame_count; // frame count
125
126 int32_t chop(VerificationType* locals, int32_t length, int32_t chops);
127 VerificationType parse_verification_type(u1* flags, TRAPS);
128 void check_verification_type_array_size(
129 int32_t size, int32_t max_size, TRAPS) {
130 if (size < 0 || size > max_size) {
131 // Since this error could be caused someone rewriting the method
132 // but not knowing to update the stackmap data, we call the the
133 // verifier's error method, which may not throw an exception and
134 // failover to the old verifier instead.
135 _verifier->class_format_error(
136 "StackMapTable format error: bad type array size");
137 }
138 }
139
140 enum {
141 SAME_LOCALS_1_STACK_ITEM_EXTENDED = 247,
142 SAME_EXTENDED = 251,
143 FULL = 255
144 };
145
146 public:
147 // Constructor
148 StackMapReader(ClassVerifier* v, StackMapStream* stream, char* code_data,
149 int32_t code_len, TRAPS) :
150 _verifier(v), _stream(stream),
151 _code_data(code_data), _code_length(code_len) {
152 methodHandle m = v->method();
153 if (m->has_stackmap_table()) {
154 _cp = constantPoolHandle(THREAD, m->constants());
155 _frame_count = _stream->get_u2(CHECK);
156 } else {
157 // There's no stackmap table present. Frame count and size are 0.
158 _frame_count = 0;
159 }
160 }
161
162 inline int32_t get_frame_count() const { return _frame_count; }
163 StackMapFrame* next(StackMapFrame* pre_frame, bool first,
164 u2 max_locals, u2 max_stack, TRAPS);
165
166 void check_end(TRAPS) {
167 if (!_stream->at_end()) {
168 StackMapStream::stackmap_format_error("wrong attribute size", CHECK);
169 }
170 }
171 };
172
173 #endif // SHARE_VM_CLASSFILE_STACKMAPTABLE_HPP