stackMapTable.hpp revision 6760:22b98ab2a69f 
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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
36class StackMapReader;
37
38// StackMapTable class is the StackMap table used by type checker
39class 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  // 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
86class 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
114class 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
174