1 /*
2 * Copyright (c) 2003, 2010, 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 #include "precompiled.hpp"
26 #include "classfile/stackMapFrame.hpp"
27 #include "classfile/verifier.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "oops/symbol.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "utilities/globalDefinitions.hpp"
33
34 StackMapFrame::StackMapFrame(u2 max_locals, u2 max_stack, ClassVerifier* v) :
35 _offset(0), _locals_size(0), _stack_size(0), _flags(0),
36 _max_locals(max_locals), _max_stack(max_stack),
37 _verifier(v) {
38 Thread* thr = v->thread();
39 _locals = NEW_RESOURCE_ARRAY_IN_THREAD(thr, VerificationType, max_locals);
40 _stack = NEW_RESOURCE_ARRAY_IN_THREAD(thr, VerificationType, max_stack);
41 int32_t i;
42 for(i = 0; i < max_locals; i++) {
43 _locals[i] = VerificationType::bogus_type();
44 }
45 for(i = 0; i < max_stack; i++) {
46 _stack[i] = VerificationType::bogus_type();
47 }
48 }
49
50 StackMapFrame* StackMapFrame::frame_in_exception_handler(u1 flags) {
51 Thread* thr = _verifier->thread();
52 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(thr, VerificationType, 1);
53 StackMapFrame* frame = new StackMapFrame(_offset, flags, _locals_size, 0, _max_locals, _max_stack, _locals, stack, _verifier);
54 return frame;
55 }
56
57 bool StackMapFrame::has_new_object() const {
58 int32_t i;
59 for (i = 0; i < _max_locals; i++) {
60 if (_locals[i].is_uninitialized()) {
61 return true;
62 }
63 }
64 for (i = 0; i < _stack_size; i++) {
65 if (_stack[i].is_uninitialized()) {
66 return true;
67 }
68 }
69 return false;
70 }
71
72 void StackMapFrame::initialize_object(
73 VerificationType old_object, VerificationType new_object) {
74 int32_t i;
75 for (i = 0; i < _max_locals; i++) {
76 if (_locals[i].equals(old_object)) {
77 _locals[i] = new_object;
78 }
79 }
80 for (i = 0; i < _stack_size; i++) {
81 if (_stack[i].equals(old_object)) {
82 _stack[i] = new_object;
83 }
84 }
85 if (old_object == VerificationType::uninitialized_this_type()) {
86 // "this" has been initialized - reset flags
87 _flags = 0;
88 }
89 }
90
91 VerificationType StackMapFrame::set_locals_from_arg(
92 const methodHandle m, VerificationType thisKlass, TRAPS) {
93 SignatureStream ss(m->signature());
94 int init_local_num = 0;
95 if (!m->is_static()) {
96 init_local_num++;
97 // add one extra argument for instance method
98 if (m->name() == vmSymbols::object_initializer_name() &&
99 thisKlass.name() != vmSymbols::java_lang_Object()) {
100 _locals[0] = VerificationType::uninitialized_this_type();
101 _flags |= FLAG_THIS_UNINIT;
102 } else {
103 _locals[0] = thisKlass;
104 }
105 }
106
107 // local num may be greater than size of parameters because long/double occupies two slots
108 while(!ss.at_return_type()) {
109 init_local_num += _verifier->change_sig_to_verificationType(
110 &ss, &_locals[init_local_num],
111 CHECK_VERIFY_(verifier(), VerificationType::bogus_type()));
112 ss.next();
113 }
114 _locals_size = init_local_num;
115
116 switch (ss.type()) {
117 case T_OBJECT:
118 case T_ARRAY:
119 {
120 Symbol* sig = ss.as_symbol(CHECK_(VerificationType::bogus_type()));
121 // Create another symbol to save as signature stream unreferences
122 // this symbol.
123 Symbol* sig_copy =
124 verifier()->create_temporary_symbol(sig, 0, sig->utf8_length(),
125 CHECK_(VerificationType::bogus_type()));
126 assert(sig_copy == sig, "symbols don't match");
127 return VerificationType::reference_type(sig_copy);
128 }
129 case T_INT: return VerificationType::integer_type();
130 case T_BYTE: return VerificationType::byte_type();
131 case T_CHAR: return VerificationType::char_type();
132 case T_SHORT: return VerificationType::short_type();
133 case T_BOOLEAN: return VerificationType::boolean_type();
134 case T_FLOAT: return VerificationType::float_type();
135 case T_DOUBLE: return VerificationType::double_type();
136 case T_LONG: return VerificationType::long_type();
137 case T_VOID: return VerificationType::bogus_type();
138 default:
139 ShouldNotReachHere();
140 }
141 return VerificationType::bogus_type();
142 }
143
144 void StackMapFrame::copy_locals(const StackMapFrame* src) {
145 int32_t len = src->locals_size() < _locals_size ?
146 src->locals_size() : _locals_size;
147 for (int32_t i = 0; i < len; i++) {
148 _locals[i] = src->locals()[i];
149 }
150 }
151
152 void StackMapFrame::copy_stack(const StackMapFrame* src) {
153 int32_t len = src->stack_size() < _stack_size ?
154 src->stack_size() : _stack_size;
155 for (int32_t i = 0; i < len; i++) {
156 _stack[i] = src->stack()[i];
157 }
158 }
159
160
161 bool StackMapFrame::is_assignable_to(
162 VerificationType* from, VerificationType* to, int32_t len, TRAPS) const {
163 for (int32_t i = 0; i < len; i++) {
164 bool subtype = to[i].is_assignable_from(
165 from[i], verifier(), THREAD);
166 if (!subtype) {
167 return false;
168 }
169 }
170 return true;
171 }
172
173 bool StackMapFrame::has_flag_match_exception(
174 const StackMapFrame* target) const {
175 // We allow flags of {UninitThis} to assign to {} if-and-only-if the
176 // target frame does not depend upon the current type.
177 // This is slightly too strict, as we need only enforce that the
178 // slots that were initialized by the <init> (the things that were
179 // UninitializedThis before initialize_object() converted them) are unused.
180 // However we didn't save that information so we'll enforce this upon
181 // anything that might have been initialized. This is a rare situation
182 // and javac never generates code that would end up here, but some profilers
183 // (such as NetBeans) might, when adding exception handlers in <init>
184 // methods to cover the invokespecial instruction. See 7020118.
185
186 assert(max_locals() == target->max_locals() &&
187 stack_size() == target->stack_size(), "StackMap sizes must match");
188
189 VerificationType top = VerificationType::top_type();
190 VerificationType this_type = verifier()->current_type();
191
192 if (!flag_this_uninit() || target->flags() != 0) {
193 return false;
194 }
195
196 for (int i = 0; i < target->locals_size(); ++i) {
197 if (locals()[i] == this_type && target->locals()[i] != top) {
198 return false;
199 }
200 }
201
202 for (int i = 0; i < target->stack_size(); ++i) {
203 if (stack()[i] == this_type && target->stack()[i] != top) {
204 return false;
205 }
206 }
207
208 return true;
209 }
210
211 bool StackMapFrame::is_assignable_to(
212 const StackMapFrame* target, bool is_exception_handler, TRAPS) const {
213 if (_max_locals != target->max_locals() ||
214 _stack_size != target->stack_size()) {
215 return false;
216 }
217 // Only need to compare type elements up to target->locals() or target->stack().
218 // The remaining type elements in this state can be ignored because they are
219 // assignable to bogus type.
220 bool match_locals = is_assignable_to(
221 _locals, target->locals(), target->locals_size(), CHECK_false);
222 bool match_stack = is_assignable_to(
223 _stack, target->stack(), _stack_size, CHECK_false);
224 bool match_flags = (_flags | target->flags()) == target->flags();
225
226 return match_locals && match_stack &&
227 (match_flags || (is_exception_handler && has_flag_match_exception(target)));
228 }
229
230 VerificationType StackMapFrame::pop_stack_ex(VerificationType type, TRAPS) {
231 if (_stack_size <= 0) {
232 verifier()->verify_error(_offset, "Operand stack underflow");
233 return VerificationType::bogus_type();
234 }
235 VerificationType top = _stack[--_stack_size];
236 bool subtype = type.is_assignable_from(
237 top, verifier(), CHECK_(VerificationType::bogus_type()));
238 if (!subtype) {
239 verifier()->verify_error(_offset, "Bad type on operand stack");
240 return VerificationType::bogus_type();
241 }
242 NOT_PRODUCT( _stack[_stack_size] = VerificationType::bogus_type(); )
243 return top;
244 }
245
246 VerificationType StackMapFrame::get_local(
247 int32_t index, VerificationType type, TRAPS) {
248 if (index >= _max_locals) {
249 verifier()->verify_error(_offset, "Local variable table overflow");
250 return VerificationType::bogus_type();
251 }
252 bool subtype = type.is_assignable_from(_locals[index],
253 verifier(), CHECK_(VerificationType::bogus_type()));
254 if (!subtype) {
255 verifier()->verify_error(_offset, "Bad local variable type");
256 return VerificationType::bogus_type();
257 }
258 if(index >= _locals_size) { _locals_size = index + 1; }
259 return _locals[index];
260 }
261
262 void StackMapFrame::get_local_2(
263 int32_t index, VerificationType type1, VerificationType type2, TRAPS) {
264 assert(type1.is_long() || type1.is_double(), "must be long/double");
265 assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");
266 if (index >= _locals_size - 1) {
267 verifier()->verify_error(_offset, "get long/double overflows locals");
268 return;
269 }
270 bool subtype1 = type1.is_assignable_from(
271 _locals[index], verifier(), CHECK);
272 bool subtype2 = type2.is_assignable_from(
273 _locals[index+1], verifier(), CHECK);
274 if (!subtype1 || !subtype2) {
275 verifier()->verify_error(_offset, "Bad local variable type");
276 return;
277 }
278 }
279
280 void StackMapFrame::set_local(int32_t index, VerificationType type, TRAPS) {
281 assert(!type.is_check(), "Must be a real type");
282 if (index >= _max_locals) {
283 verifier()->verify_error("Local variable table overflow", _offset);
284 return;
285 }
286 // If type at index is double or long, set the next location to be unusable
287 if (_locals[index].is_double() || _locals[index].is_long()) {
288 assert((index + 1) < _locals_size, "Local variable table overflow");
289 _locals[index + 1] = VerificationType::bogus_type();
290 }
291 // If type at index is double_2 or long_2, set the previous location to be unusable
292 if (_locals[index].is_double2() || _locals[index].is_long2()) {
293 assert(index >= 1, "Local variable table underflow");
294 _locals[index - 1] = VerificationType::bogus_type();
295 }
296 _locals[index] = type;
297 if (index >= _locals_size) {
298 #ifdef ASSERT
299 for (int i=_locals_size; i<index; i++) {
300 assert(_locals[i] == VerificationType::bogus_type(),
301 "holes must be bogus type");
302 }
303 #endif
304 _locals_size = index + 1;
305 }
306 }
307
308 void StackMapFrame::set_local_2(
309 int32_t index, VerificationType type1, VerificationType type2, TRAPS) {
310 assert(type1.is_long() || type1.is_double(), "must be long/double");
311 assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");
312 if (index >= _max_locals - 1) {
313 verifier()->verify_error("Local variable table overflow", _offset);
314 return;
315 }
316 // If type at index+1 is double or long, set the next location to be unusable
317 if (_locals[index+1].is_double() || _locals[index+1].is_long()) {
318 assert((index + 2) < _locals_size, "Local variable table overflow");
319 _locals[index + 2] = VerificationType::bogus_type();
320 }
321 // If type at index is double_2 or long_2, set the previous location to be unusable
322 if (_locals[index].is_double2() || _locals[index].is_long2()) {
323 assert(index >= 1, "Local variable table underflow");
324 _locals[index - 1] = VerificationType::bogus_type();
325 }
326 _locals[index] = type1;
327 _locals[index+1] = type2;
328 if (index >= _locals_size - 1) {
329 #ifdef ASSERT
330 for (int i=_locals_size; i<index; i++) {
331 assert(_locals[i] == VerificationType::bogus_type(),
332 "holes must be bogus type");
333 }
334 #endif
335 _locals_size = index + 2;
336 }
337 }
338
339 #ifndef PRODUCT
340
341 void StackMapFrame::print() const {
342 tty->print_cr("stackmap_frame[%d]:", _offset);
343 tty->print_cr("flags = 0x%x", _flags);
344 tty->print("locals[%d] = { ", _locals_size);
345 for (int32_t i = 0; i < _locals_size; i++) {
346 _locals[i].print_on(tty);
347 }
348 tty->print_cr(" }");
349 tty->print("stack[%d] = { ", _stack_size);
350 for (int32_t j = 0; j < _stack_size; j++) {
351 _stack[j].print_on(tty);
352 }
353 tty->print_cr(" }");
354 }
355
356 #endif