1 /*
2 * Copyright (c) 2003, 2016, 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.
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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, 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, 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 void print_on(outputStream* str) const;
80 };
81
82 class StackMapStream : StackObj {
83 private:
84 Array<u1>* _data;
85 int _index;
86 public:
87 StackMapStream(Array<u1>* ah)
88 : _data(ah), _index(0) {
89 }
90 u1 get_u1(TRAPS) {
91 if (_data == NULL || _index >= _data->length()) {
92 stackmap_format_error("access beyond the end of attribute", CHECK_0);
93 }
94 return _data->at(_index++);
95 }
96 u2 get_u2(TRAPS) {
97 if (_data == NULL || _index >= _data->length() - 1) {
98 stackmap_format_error("access beyond the end of attribute", CHECK_0);
99 }
100 u2 res = Bytes::get_Java_u2(_data->adr_at(_index));
101 _index += 2;
102 return res;
103 }
104 bool at_end() {
105 return (_data == NULL) || (_index == _data->length());
106 }
107 static void stackmap_format_error(const char* msg, TRAPS);
108 };
109
110 class StackMapReader : StackObj {
111 private:
112 // information about the class and method
113 constantPoolHandle _cp;
114 ClassVerifier* _verifier;
115 StackMapStream* _stream;
116 char* _code_data;
117 int32_t _code_length;
118
119 // information get from the attribute
120 int32_t _frame_count; // frame count
121
122 int32_t chop(VerificationType* locals, int32_t length, int32_t chops);
123 VerificationType parse_verification_type(u1* flags, TRAPS);
124 void check_verification_type_array_size(
125 int32_t size, int32_t max_size, TRAPS) {
126 if (size < 0 || size > max_size) {
127 // Since this error could be caused someone rewriting the method
128 // but not knowing to update the stackmap data, we call the the
129 // verifier's error method, which may not throw an exception and
130 // failover to the old verifier instead.
131 _verifier->class_format_error(
132 "StackMapTable format error: bad type array size");
133 }
134 }
135
136 enum {
137 SAME_LOCALS_1_STACK_ITEM_EXTENDED = 247,
138 SAME_EXTENDED = 251,
139 FULL = 255
140 };
141
142 public:
143 // Constructor
144 StackMapReader(ClassVerifier* v, StackMapStream* stream, char* code_data,
145 int32_t code_len, TRAPS) :
146 _verifier(v), _stream(stream),
147 _code_data(code_data), _code_length(code_len) {
148 methodHandle m = v->method();
149 if (m->has_stackmap_table()) {
150 _cp = constantPoolHandle(THREAD, m->constants());
151 _frame_count = _stream->get_u2(CHECK);
152 } else {
153 // There's no stackmap table present. Frame count and size are 0.
154 _frame_count = 0;
155 }
156 }
157
158 inline int32_t get_frame_count() const { return _frame_count; }
159 StackMapFrame* next(StackMapFrame* pre_frame, bool first,
160 u2 max_locals, u2 max_stack, TRAPS);
161
162 void check_end(TRAPS) {
163 if (!_stream->at_end()) {
164 StackMapStream::stackmap_format_error("wrong attribute size", CHECK);
165 }
166 }
167 };
168
169 #endif // SHARE_VM_CLASSFILE_STACKMAPTABLE_HPP