stackMapFrame.hpp revision 1472:c18cbe5936b8 
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.
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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
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23 */
24
25// A StackMapFrame represents one frame in the stack map attribute.
26
27enum {
28  FLAG_THIS_UNINIT = 0x01
29};
30
31class StackMapFrame : public ResourceObj {
32 private:
33  int32_t _offset;
34
35  // See comment in StackMapTable about _frame_count about why these
36  // fields are int32_t instead of u2.
37  int32_t _locals_size;  // number of valid type elements in _locals
38  int32_t _stack_size;   // number of valid type elements in _stack
39
40  int32_t _max_locals;
41  int32_t _max_stack;
42
43  u1 _flags;
44  VerificationType* _locals; // local variable type array
45  VerificationType* _stack;  // operand stack type array
46
47  ClassVerifier* _verifier;  // the verifier verifying this method
48
49 public:
50  // constructors
51
52  // This constructor is used by the type checker to allocate frames
53  // in type state, which have _max_locals and _max_stack array elements
54  // in _locals and _stack.
55  StackMapFrame(u2 max_locals, u2 max_stack, ClassVerifier* verifier);
56
57  // This constructor is used to initialize stackmap frames in stackmap table,
58  // which have _locals_size and _stack_size array elements in _locals and _stack.
59  StackMapFrame(int32_t offset,
60                u1 flags,
61                u2 locals_size,
62                u2 stack_size,
63                u2 max_locals,
64                u2 max_stack,
65                VerificationType* locals,
66                VerificationType* stack,
67                ClassVerifier* v) : _offset(offset), _flags(flags),
68                                    _locals_size(locals_size),
69                                    _stack_size(stack_size),
70                                    _max_locals(max_locals),
71                                    _max_stack(max_stack),
72                                    _locals(locals), _stack(stack),
73                                    _verifier(v) { }
74
75  inline void set_offset(int32_t offset)      { _offset = offset; }
76  inline void set_verifier(ClassVerifier* v)  { _verifier = v; }
77  inline void set_flags(u1 flags)             { _flags = flags; }
78  inline void set_locals_size(u2 locals_size) { _locals_size = locals_size; }
79  inline void set_stack_size(u2 stack_size)   { _stack_size = stack_size; }
80  inline void clear_stack()                   { _stack_size = 0; }
81  inline int32_t offset()   const             { return _offset; }
82  inline ClassVerifier* verifier() const      { return _verifier; }
83  inline u1 flags() const                     { return _flags; }
84  inline int32_t locals_size() const          { return _locals_size; }
85  inline VerificationType* locals() const     { return _locals; }
86  inline int32_t stack_size() const           { return _stack_size; }
87  inline VerificationType* stack() const      { return _stack; }
88  inline int32_t max_locals() const           { return _max_locals; }
89  inline int32_t max_stack() const            { return _max_stack; }
90  inline bool flag_this_uninit() const        { return _flags & FLAG_THIS_UNINIT; }
91
92  // Set locals and stack types to bogus
93  inline void reset() {
94    int32_t i;
95    for (i = 0; i < _max_locals; i++) {
96      _locals[i] = VerificationType::bogus_type();
97    }
98    for (i = 0; i < _max_stack; i++) {
99      _stack[i] = VerificationType::bogus_type();
100    }
101  }
102
103  // Return a StackMapFrame with the same local variable array and empty stack.
104  // Stack array is allocate with unused one element.
105  StackMapFrame* frame_in_exception_handler(u1 flags);
106
107  // Set local variable type array based on m's signature.
108  VerificationType set_locals_from_arg(
109    const methodHandle m, VerificationType thisKlass, TRAPS);
110
111  // Search local variable type array and stack type array.
112  // Return true if an uninitialized object is found.
113  bool has_new_object() const;
114
115  // Search local variable type array and stack type array.
116  // Set every element with type of old_object to new_object.
117  void initialize_object(
118    VerificationType old_object, VerificationType new_object);
119
120  // Copy local variable type array in src into this local variable type array.
121  void copy_locals(const StackMapFrame* src);
122
123  // Copy stack type array in src into this stack type array.
124  void copy_stack(const StackMapFrame* src);
125
126  // Return true if this stack map frame is assignable to target.
127  bool is_assignable_to(const StackMapFrame* target, TRAPS) const;
128
129  // Push type into stack type array.
130  inline void push_stack(VerificationType type, TRAPS) {
131    assert(!type.is_check(), "Must be a real type");
132    if (_stack_size >= _max_stack) {
133      verifier()->verify_error(_offset, "Operand stack overflow");
134      return;
135    }
136    _stack[_stack_size++] = type;
137  }
138
139  inline void push_stack_2(
140      VerificationType type1, VerificationType type2, TRAPS) {
141    assert(type1.is_long() || type1.is_double(), "must be long/double");
142    assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");
143    if (_stack_size >= _max_stack - 1) {
144      verifier()->verify_error(_offset, "Operand stack overflow");
145      return;
146    }
147    _stack[_stack_size++] = type1;
148    _stack[_stack_size++] = type2;
149  }
150
151  // Pop and return the top type on stack without verifying.
152  inline VerificationType pop_stack(TRAPS) {
153    if (_stack_size <= 0) {
154      verifier()->verify_error(_offset, "Operand stack underflow");
155      return VerificationType::bogus_type();
156    }
157    // Put bogus type to indicate it's no longer valid.
158    // Added to make it consistent with the other pop_stack method.
159    VerificationType top = _stack[--_stack_size];
160    NOT_PRODUCT( _stack[_stack_size] = VerificationType::bogus_type(); )
161    return top;
162  }
163
164  // Pop and return the top type on stack type array after verifying it
165  // is assignable to type.
166  inline VerificationType pop_stack(VerificationType type, TRAPS) {
167    if (_stack_size != 0) {
168      VerificationType top = _stack[_stack_size - 1];
169      bool subtype = type.is_assignable_from(
170        top, verifier()->current_class(),
171        CHECK_(VerificationType::bogus_type()));
172      if (subtype) {
173        _stack_size --;
174        NOT_PRODUCT( _stack[_stack_size] = VerificationType::bogus_type(); )
175        return top;
176      }
177    }
178    return pop_stack_ex(type, THREAD);
179  }
180
181  inline void pop_stack_2(
182      VerificationType type1, VerificationType type2, TRAPS) {
183    assert(type1.is_long2() || type1.is_double2(), "must be long/double");
184    assert(type2.is_long() || type2.is_double(), "must be long/double_2");
185    if (_stack_size >= 2) {
186      VerificationType top1 = _stack[_stack_size - 1];
187      bool subtype1 = type1.is_assignable_from(
188        top1, verifier()->current_class(), CHECK);
189      VerificationType top2 = _stack[_stack_size - 2];
190      bool subtype2 = type2.is_assignable_from(
191        top2, verifier()->current_class(), CHECK);
192      if (subtype1 && subtype2) {
193        _stack_size -= 2;
194        NOT_PRODUCT( _stack[_stack_size] = VerificationType::bogus_type(); )
195        NOT_PRODUCT( _stack[_stack_size+1] = VerificationType::bogus_type(); )
196        return;
197      }
198    }
199    pop_stack_ex(type1, THREAD);
200    pop_stack_ex(type2, THREAD);
201  }
202
203  // Uncommon case that throws exceptions.
204  VerificationType pop_stack_ex(VerificationType type, TRAPS);
205
206  // Return the type at index in local variable array after verifying
207  // it is assignable to type.
208  VerificationType get_local(int32_t index, VerificationType type, TRAPS);
209  // For long/double.
210  void get_local_2(
211    int32_t index, VerificationType type1, VerificationType type2, TRAPS);
212
213  // Set element at index in local variable array to type.
214  void set_local(int32_t index, VerificationType type, TRAPS);
215  // For long/double.
216  void set_local_2(
217    int32_t index, VerificationType type1, VerificationType type2, TRAPS);
218
219  // Private auxiliary method used only in is_assignable_to(StackMapFrame).
220  // Returns true if src is assignable to target.
221  bool is_assignable_to(
222    VerificationType* src, VerificationType* target, int32_t len, TRAPS) const;
223
224  // Debugging
225  void print() const PRODUCT_RETURN;
226};
227