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 // A StackMapFrame represents one frame in the stack map attribute.
26
27 enum {
28 FLAG_THIS_UNINIT = 0x01
29 };
30
31 class 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 };