1 /*
2 * Copyright (c) 2003, 2016, 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/method.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),
109 _locals_size(locals_size),
110 _stack_size(stack_size),
111 _stack_mark(-1),
112 _max_locals(max_locals),
113 _max_stack(max_stack), _flags(flags),
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 // Set every element with type of old_object to new_object.
159 void initialize_object(
160 VerificationType old_object, VerificationType new_object);
161
162 // Copy local variable type array in src into this local variable type array.
163 void copy_locals(const StackMapFrame* src);
164
165 // Copy stack type array in src into this stack type array.
166 void copy_stack(const StackMapFrame* src);
167
168 // Return true if this stack map frame is assignable to target.
169 bool is_assignable_to(
170 const StackMapFrame* target, ErrorContext* ctx, TRAPS) const;
171
172 inline void set_mark() {
173 #ifdef ASSERT
174 // Put bogus type to indicate it's no longer valid.
175 if (_stack_mark != -1) {
176 for (int i = _stack_mark - 1; i >= _stack_size; --i) {
177 _stack[i] = VerificationType::bogus_type();
178 }
179 }
180 #endif // def ASSERT
181 _stack_mark = _stack_size;
182 }
183
184 // Used when an error occurs and we want to reset the stack to the state
185 // it was before operands were popped off.
186 void restore() {
187 if (_stack_mark != -1) {
188 _stack_size = _stack_mark;
189 }
190 }
191
192 // Push type into stack type array.
193 inline void push_stack(VerificationType type, TRAPS) {
194 assert(!type.is_check(), "Must be a real type");
195 if (_stack_size >= _max_stack) {
196 verifier()->verify_error(
197 ErrorContext::stack_overflow(_offset, this),
198 "Operand stack overflow");
199 return;
200 }
201 _stack[_stack_size++] = type;
202 }
203
204 inline void push_stack_2(
205 VerificationType type1, VerificationType type2, TRAPS) {
206 assert(type1.is_long() || type1.is_double(), "must be long/double");
207 assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");
208 if (_stack_size >= _max_stack - 1) {
209 verifier()->verify_error(
210 ErrorContext::stack_overflow(_offset, this),
211 "Operand stack overflow");
212 return;
213 }
214 _stack[_stack_size++] = type1;
215 _stack[_stack_size++] = type2;
216 }
217
218 // Pop and return the top type on stack without verifying.
219 inline VerificationType pop_stack(TRAPS) {
220 if (_stack_size <= 0) {
221 verifier()->verify_error(
222 ErrorContext::stack_underflow(_offset, this),
223 "Operand stack underflow");
224 return VerificationType::bogus_type();
225 }
226 VerificationType top = _stack[--_stack_size];
227 return top;
228 }
229
230 // Pop and return the top type on stack type array after verifying it
231 // is assignable to type.
232 inline VerificationType pop_stack(VerificationType type, TRAPS) {
233 if (_stack_size != 0) {
234 VerificationType top = _stack[_stack_size - 1];
235 bool subtype = type.is_assignable_from(
236 top, verifier(), false, CHECK_(VerificationType::bogus_type()));
237 if (subtype) {
238 --_stack_size;
239 return top;
240 }
241 }
242 return pop_stack_ex(type, THREAD);
243 }
244
245 inline void pop_stack_2(
246 VerificationType type1, VerificationType type2, TRAPS) {
247 assert(type1.is_long2() || type1.is_double2(), "must be long/double");
248 assert(type2.is_long() || type2.is_double(), "must be long/double_2");
249 if (_stack_size >= 2) {
250 VerificationType top1 = _stack[_stack_size - 1];
251 bool subtype1 = type1.is_assignable_from(top1, verifier(), false, CHECK);
252 VerificationType top2 = _stack[_stack_size - 2];
253 bool subtype2 = type2.is_assignable_from(top2, verifier(), false, CHECK);
254 if (subtype1 && subtype2) {
255 _stack_size -= 2;
256 return;
257 }
258 }
259 pop_stack_ex(type1, THREAD);
260 pop_stack_ex(type2, THREAD);
261 }
262
263 VerificationType local_at(int index) {
264 return _locals[index];
265 }
266
267 VerificationType stack_at(int index) {
268 return _stack[index];
269 }
270
271 // Uncommon case that throws exceptions.
272 VerificationType pop_stack_ex(VerificationType type, TRAPS);
273
274 // Return the type at index in local variable array after verifying
275 // it is assignable to type.
276 VerificationType get_local(int32_t index, VerificationType type, TRAPS);
277 // For long/double.
278 void get_local_2(
279 int32_t index, VerificationType type1, VerificationType type2, TRAPS);
280
281 // Set element at index in local variable array to type.
282 void set_local(int32_t index, VerificationType type, TRAPS);
283 // For long/double.
284 void set_local_2(
285 int32_t index, VerificationType type1, VerificationType type2, TRAPS);
286
287 // Private auxiliary method used only in is_assignable_to(StackMapFrame).
288 // Returns true if src is assignable to target.
289 int is_assignable_to(
290 VerificationType* src, VerificationType* target, int32_t len, TRAPS) const;
291
292 TypeOrigin stack_top_ctx();
293
294 void print_on(outputStream* str) const;
295 };
296
297 #endif // SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP