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 };