1 /*
2 * Copyright (c) 2003, 2014, 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 #ifndef SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP
26 #define SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP
27
28 #include "classfile/verificationType.hpp"
29 #include "classfile/verifier.hpp"
30 #include "oops/methodOop.hpp"
31 #include "runtime/handles.hpp"
32 #include "runtime/signature.hpp"
33 #include "utilities/exceptions.hpp"
34
35 // A StackMapFrame represents one frame in the stack map attribute.
36
37 class TypeContext;
38
39 enum {
40 FLAG_THIS_UNINIT = 0x01
41 };
42
43 class StackMapFrame : public ResourceObj {
44 private:
45 int32_t _offset;
46
47 // See comment in StackMapTable about _frame_count about why these
48 // fields are int32_t instead of u2.
49 int32_t _locals_size; // number of valid type elements in _locals
50 int32_t _stack_size; // number of valid type elements in _stack
51
52 int32_t _stack_mark; // Records the size of the stack prior to an
53 // instruction modification, to allow rewinding
54 // when/if an error occurs.
55
56 int32_t _max_locals;
57 int32_t _max_stack;
58
59 u1 _flags;
60 VerificationType* _locals; // local variable type array
61 VerificationType* _stack; // operand stack type array
62
63 ClassVerifier* _verifier; // the verifier verifying this method
64
65 StackMapFrame(const StackMapFrame& cp) :
66 _offset(cp._offset), _locals_size(cp._locals_size),
67 _stack_size(cp._stack_size), _stack_mark(cp._stack_mark),
68 _max_locals(cp._max_locals), _max_stack(cp._max_stack),
69 _flags(cp._flags) {
70 _locals = NEW_RESOURCE_ARRAY(VerificationType, _max_locals);
71 for (int i = 0; i < _max_locals; ++i) {
72 if (i < _locals_size) {
73 _locals[i] = cp._locals[i];
74 } else {
75 _locals[i] = VerificationType::bogus_type();
76 }
77 }
78 int ss = MAX2(_stack_size, _stack_mark);
79 _stack = NEW_RESOURCE_ARRAY(VerificationType, _max_stack);
80 for (int i = 0; i < _max_stack; ++i) {
81 if (i < ss) {
82 _stack[i] = cp._stack[i];
83 } else {
84 _stack[i] = VerificationType::bogus_type();
85 }
86 }
87 _verifier = NULL;
88 }
89
90 public:
91 // constructors
92
93 // This constructor is used by the type checker to allocate frames
94 // in type state, which have _max_locals and _max_stack array elements
95 // in _locals and _stack.
96 StackMapFrame(u2 max_locals, u2 max_stack, ClassVerifier* verifier);
97
98 // This constructor is used to initialize stackmap frames in stackmap table,
99 // which have _locals_size and _stack_size array elements in _locals and _stack.
100 StackMapFrame(int32_t offset,
101 u1 flags,
102 u2 locals_size,
103 u2 stack_size,
104 u2 max_locals,
105 u2 max_stack,
106 VerificationType* locals,
107 VerificationType* stack,
108 ClassVerifier* v) : _offset(offset), _flags(flags),
109 _locals_size(locals_size),
110 _stack_size(stack_size),
111 _stack_mark(-1),
112 _max_locals(max_locals),
113 _max_stack(max_stack),
114 _locals(locals), _stack(stack),
115 _verifier(v) { }
116
117 static StackMapFrame* copy(StackMapFrame* smf) {
118 return new StackMapFrame(*smf);
119 }
120
121 inline void set_offset(int32_t offset) { _offset = offset; }
122 inline void set_verifier(ClassVerifier* v) { _verifier = v; }
123 inline void set_flags(u1 flags) { _flags = flags; }
124 inline void set_locals_size(u2 locals_size) { _locals_size = locals_size; }
125 inline void set_stack_size(u2 stack_size) { _stack_size = _stack_mark = stack_size; }
126 inline void clear_stack() { _stack_size = 0; }
127 inline int32_t offset() const { return _offset; }
128 inline ClassVerifier* verifier() const { return _verifier; }
129 inline u1 flags() const { return _flags; }
130 inline int32_t locals_size() const { return _locals_size; }
131 inline VerificationType* locals() const { return _locals; }
132 inline int32_t stack_size() const { return _stack_size; }
133 inline VerificationType* stack() const { return _stack; }
134 inline int32_t max_locals() const { return _max_locals; }
135 inline int32_t max_stack() const { return _max_stack; }
136 inline bool flag_this_uninit() const { return _flags & FLAG_THIS_UNINIT; }
137
138 // Set locals and stack types to bogus
139 inline void reset() {
140 int32_t i;
141 for (i = 0; i < _max_locals; i++) {
142 _locals[i] = VerificationType::bogus_type();
143 }
144 for (i = 0; i < _max_stack; i++) {
145 _stack[i] = VerificationType::bogus_type();
146 }
147 }
148
149 // Return a StackMapFrame with the same local variable array and empty stack.
150 // Stack array is allocate with unused one element.
151 StackMapFrame* frame_in_exception_handler(u1 flags);
152
153 // Set local variable type array based on m's signature.
154 VerificationType set_locals_from_arg(
155 const methodHandle m, VerificationType thisKlass, TRAPS);
156
157 // Search local variable type array and stack type array.
158 // Return true if an uninitialized object is found that is
159 // not equal to the corresponding object on the target frame.
160 bool has_unique_new_object(const StackMapFrame *target_frame) const;
161
162 // Search local variable type array and stack type array.
163 // Set every element with type of old_object to new_object.
164 void initialize_object(
165 VerificationType old_object, VerificationType new_object);
166
167 // Copy local variable type array in src into this local variable type array.
168 void copy_locals(const StackMapFrame* src);
169
170 // Copy stack type array in src into this stack type array.
171 void copy_stack(const StackMapFrame* src);
172
173 // Return true if this stack map frame is assignable to target.
174 bool is_assignable_to(
175 const StackMapFrame* target, bool is_exception_handler,
176 ErrorContext* ctx, TRAPS) const;
177
178 inline void set_mark() {
179 #ifdef DEBUG
180 // Put bogus type to indicate it's no longer valid.
181 if (_stack_mark != -1) {
182 for (int i = _stack_mark; i >= _stack_size; --i) {
183 _stack[i] = VerificationType::bogus_type();
184 }
185 }
186 #endif // def DEBUG
187 _stack_mark = _stack_size;
188 }
189
190 // Used when an error occurs and we want to reset the stack to the state
191 // it was before operands were popped off.
192 void restore() {
193 if (_stack_mark != -1) {
194 _stack_size = _stack_mark;
195 }
196 }
197
198 // Push type into stack type array.
199 inline void push_stack(VerificationType type, TRAPS) {
200 assert(!type.is_check(), "Must be a real type");
201 if (_stack_size >= _max_stack) {
202 verifier()->verify_error(
203 ErrorContext::stack_overflow(_offset, this),
204 "Operand stack overflow");
205 return;
206 }
207 _stack[_stack_size++] = type;
208 }
209
210 inline void push_stack_2(
211 VerificationType type1, VerificationType type2, TRAPS) {
212 assert(type1.is_long() || type1.is_double(), "must be long/double");
213 assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");
214 if (_stack_size >= _max_stack - 1) {
215 verifier()->verify_error(
216 ErrorContext::stack_overflow(_offset, this),
217 "Operand stack overflow");
218 return;
219 }
220 _stack[_stack_size++] = type1;
221 _stack[_stack_size++] = type2;
222 }
223
224 // Pop and return the top type on stack without verifying.
225 inline VerificationType pop_stack(TRAPS) {
226 if (_stack_size <= 0) {
227 verifier()->verify_error(
228 ErrorContext::stack_underflow(_offset, this),
229 "Operand stack underflow");
230 return VerificationType::bogus_type();
231 }
232 VerificationType top = _stack[--_stack_size];
233 return top;
234 }
235
236 // Pop and return the top type on stack type array after verifying it
237 // is assignable to type.
238 inline VerificationType pop_stack(VerificationType type, TRAPS) {
239 if (_stack_size != 0) {
240 VerificationType top = _stack[_stack_size - 1];
241 bool subtype = type.is_assignable_from(
242 top, verifier(), CHECK_(VerificationType::bogus_type()));
243 if (subtype) {
244 --_stack_size;
245 return top;
246 }
247 }
248 return pop_stack_ex(type, THREAD);
249 }
250
251 inline void pop_stack_2(
252 VerificationType type1, VerificationType type2, TRAPS) {
253 assert(type1.is_long2() || type1.is_double2(), "must be long/double");
254 assert(type2.is_long() || type2.is_double(), "must be long/double_2");
255 if (_stack_size >= 2) {
256 VerificationType top1 = _stack[_stack_size - 1];
257 bool subtype1 = type1.is_assignable_from(top1, verifier(), CHECK);
258 VerificationType top2 = _stack[_stack_size - 2];
259 bool subtype2 = type2.is_assignable_from(top2, verifier(), CHECK);
260 if (subtype1 && subtype2) {
261 _stack_size -= 2;
262 return;
263 }
264 }
265 pop_stack_ex(type1, THREAD);
266 pop_stack_ex(type2, THREAD);
267 }
268
269 VerificationType local_at(int index) {
270 return _locals[index];
271 }
272
273 VerificationType stack_at(int index) {
274 return _stack[index];
275 }
276
277 // Uncommon case that throws exceptions.
278 VerificationType pop_stack_ex(VerificationType type, TRAPS);
279
280 // Return the type at index in local variable array after verifying
281 // it is assignable to type.
282 VerificationType get_local(int32_t index, VerificationType type, TRAPS);
283 // For long/double.
284 void get_local_2(
285 int32_t index, VerificationType type1, VerificationType type2, TRAPS);
286
287 // Set element at index in local variable array to type.
288 void set_local(int32_t index, VerificationType type, TRAPS);
289 // For long/double.
290 void set_local_2(
291 int32_t index, VerificationType type1, VerificationType type2, TRAPS);
292
293 // Private auxiliary method used only in is_assignable_to(StackMapFrame).
294 // Returns true if src is assignable to target.
295 int is_assignable_to(
296 VerificationType* src, VerificationType* target, int32_t len, TRAPS) const;
297
298 bool has_flag_match_exception(const StackMapFrame* target) const;
299
300 TypeOrigin stack_top_ctx();
301
302 void print_on(outputStream* str) const;
303 };
304
305 #endif // SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP