1 /*
2 * Copyright (c) 2000, 2019, 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 "logging/log.hpp"
27 #include "memory/resourceArea.hpp"
28 #include "oops/constantPool.inline.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "oops/symbol.hpp"
31 #include "prims/methodComparator.hpp"
32 #include "runtime/handles.inline.hpp"
33 #include "utilities/globalDefinitions.hpp"
34
35 BytecodeStream *MethodComparator::_s_old;
36 BytecodeStream *MethodComparator::_s_new;
37 ConstantPool* MethodComparator::_old_cp;
38 ConstantPool* MethodComparator::_new_cp;
39
40 bool MethodComparator::methods_EMCP(Method* old_method, Method* new_method) {
41 if (old_method->code_size() != new_method->code_size())
42 return false;
43 if (check_stack_and_locals_size(old_method, new_method) != 0) {
44 if (log_is_enabled(Debug, redefine, class, methodcomparator)) {
45 ResourceMark rm;
46 log_debug(redefine, class, methodcomparator)
47 ("Methods %s non-comparable with diagnosis %d",
48 old_method->name()->as_C_string(), check_stack_and_locals_size(old_method, new_method));
49 }
50 return false;
51 }
52
53 _old_cp = old_method->constants();
54 _new_cp = new_method->constants();
55 Thread* THREAD = Thread::current();
56 BytecodeStream s_old(methodHandle(THREAD, old_method));
57 BytecodeStream s_new(methodHandle(THREAD, new_method));
58 _s_old = &s_old;
59 _s_new = &s_new;
60 Bytecodes::Code c_old, c_new;
61
62 while ((c_old = s_old.next()) >= 0) {
63 if ((c_new = s_new.next()) < 0 || c_old != c_new)
64 return false;
65
66 if (! args_same(c_old, c_new))
67 return false;
68 }
69 return true;
70 }
71
72 bool MethodComparator::args_same(Bytecodes::Code c_old, Bytecodes::Code c_new) {
73 // BytecodeStream returns the correct standard Java bytecodes for various "fast"
74 // bytecode versions, so we don't have to bother about them here..
75 switch (c_old) {
76 case Bytecodes::_new : // fall through
77 case Bytecodes::_anewarray : // fall through
78 case Bytecodes::_multianewarray : // fall through
79 case Bytecodes::_checkcast : // fall through
80 case Bytecodes::_instanceof : {
81 u2 cpi_old = _s_old->get_index_u2();
82 u2 cpi_new = _s_new->get_index_u2();
83 if ((_old_cp->klass_at_noresolve(cpi_old) != _new_cp->klass_at_noresolve(cpi_new)))
84 return false;
85 if (c_old == Bytecodes::_multianewarray &&
86 *(jbyte*)(_s_old->bcp() + 3) != *(jbyte*)(_s_new->bcp() + 3))
87 return false;
88 break;
89 }
90
91 case Bytecodes::_getstatic : // fall through
92 case Bytecodes::_putstatic : // fall through
93 case Bytecodes::_getfield : // fall through
94 case Bytecodes::_putfield : // fall through
95 case Bytecodes::_invokevirtual : // fall through
96 case Bytecodes::_invokespecial : // fall through
97 case Bytecodes::_invokestatic : // fall through
98 case Bytecodes::_invokeinterface : {
99 int cpci_old = _s_old->get_index_u2_cpcache();
100 int cpci_new = _s_new->get_index_u2_cpcache();
101 // Check if the names of classes, field/method names and signatures at these indexes
102 // are the same. Indices which are really into constantpool cache (rather than constant
103 // pool itself) are accepted by the constantpool query routines below.
104 if ((_old_cp->klass_ref_at_noresolve(cpci_old) != _new_cp->klass_ref_at_noresolve(cpci_new)) ||
105 (_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
106 (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
107 return false;
108 break;
109 }
110 case Bytecodes::_invokedynamic: {
111 int cpci_old = _s_old->get_index_u4();
112 int cpci_new = _s_new->get_index_u4();
113
114 // Check if the names of classes, field/method names and signatures at these indexes
115 // are the same. Indices which are really into constantpool cache (rather than constant
116 // pool itself) are accepted by the constantpool query routines below.
117 if ((_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
118 (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
119 return false;
120
121 // Translate object indexes to constant pool cache indexes.
122 cpci_old = _old_cp->invokedynamic_cp_cache_index(cpci_old);
123 cpci_new = _new_cp->invokedynamic_cp_cache_index(cpci_new);
124
125 int cpi_old = _old_cp->cache()->entry_at(cpci_old)->constant_pool_index();
126 int cpi_new = _new_cp->cache()->entry_at(cpci_new)->constant_pool_index();
127 int bsm_old = _old_cp->bootstrap_method_ref_index_at(cpi_old);
128 int bsm_new = _new_cp->bootstrap_method_ref_index_at(cpi_new);
129 if (!pool_constants_same(bsm_old, bsm_new))
130 return false;
131 int cnt_old = _old_cp->bootstrap_argument_count_at(cpi_old);
132 int cnt_new = _new_cp->bootstrap_argument_count_at(cpi_new);
133 if (cnt_old != cnt_new)
134 return false;
135 for (int arg_i = 0; arg_i < cnt_old; arg_i++) {
136 int idx_old = _old_cp->bootstrap_argument_index_at(cpi_old, arg_i);
137 int idx_new = _new_cp->bootstrap_argument_index_at(cpi_new, arg_i);
138 if (!pool_constants_same(idx_old, idx_new))
139 return false;
140 }
141 break;
142 }
143
144 case Bytecodes::_ldc : // fall through
145 case Bytecodes::_ldc_w : {
146 Bytecode_loadconstant ldc_old(_s_old->method(), _s_old->bci());
147 Bytecode_loadconstant ldc_new(_s_new->method(), _s_new->bci());
148 int cpi_old = ldc_old.pool_index();
149 int cpi_new = ldc_new.pool_index();
150 if (!pool_constants_same(cpi_old, cpi_new))
151 return false;
152 break;
153 }
154
155 case Bytecodes::_ldc2_w : {
156 u2 cpi_old = _s_old->get_index_u2();
157 u2 cpi_new = _s_new->get_index_u2();
158 constantTag tag_old = _old_cp->tag_at(cpi_old);
159 constantTag tag_new = _new_cp->tag_at(cpi_new);
160 if (tag_old.value() != tag_new.value())
161 return false;
162 if (tag_old.is_long()) {
163 if (_old_cp->long_at(cpi_old) != _new_cp->long_at(cpi_new))
164 return false;
165 } else {
166 // Use jlong_cast to compare the bits rather than numerical values.
167 // This makes a difference for NaN constants.
168 if (jlong_cast(_old_cp->double_at(cpi_old)) != jlong_cast(_new_cp->double_at(cpi_new)))
169 return false;
170 }
171 break;
172 }
173
174 case Bytecodes::_bipush :
175 if (_s_old->bcp()[1] != _s_new->bcp()[1])
176 return false;
177 break;
178
179 case Bytecodes::_sipush :
180 if (_s_old->get_index_u2() != _s_new->get_index_u2())
181 return false;
182 break;
183
184 case Bytecodes::_aload : // fall through
185 case Bytecodes::_astore : // fall through
186 case Bytecodes::_dload : // fall through
187 case Bytecodes::_dstore : // fall through
188 case Bytecodes::_fload : // fall through
189 case Bytecodes::_fstore : // fall through
190 case Bytecodes::_iload : // fall through
191 case Bytecodes::_istore : // fall through
192 case Bytecodes::_lload : // fall through
193 case Bytecodes::_lstore : // fall through
194 case Bytecodes::_ret :
195 if (_s_old->is_wide() != _s_new->is_wide())
196 return false;
197 if (_s_old->get_index() != _s_new->get_index())
198 return false;
199 break;
200
201 case Bytecodes::_goto : // fall through
202 case Bytecodes::_if_acmpeq : // fall through
203 case Bytecodes::_if_acmpne : // fall through
204 case Bytecodes::_if_icmpeq : // fall through
205 case Bytecodes::_if_icmpne : // fall through
206 case Bytecodes::_if_icmplt : // fall through
207 case Bytecodes::_if_icmpge : // fall through
208 case Bytecodes::_if_icmpgt : // fall through
209 case Bytecodes::_if_icmple : // fall through
210 case Bytecodes::_ifeq : // fall through
211 case Bytecodes::_ifne : // fall through
212 case Bytecodes::_iflt : // fall through
213 case Bytecodes::_ifge : // fall through
214 case Bytecodes::_ifgt : // fall through
215 case Bytecodes::_ifle : // fall through
216 case Bytecodes::_ifnonnull : // fall through
217 case Bytecodes::_ifnull : // fall through
218 case Bytecodes::_jsr : {
219 int old_ofs = _s_old->bytecode().get_offset_s2(c_old);
220 int new_ofs = _s_new->bytecode().get_offset_s2(c_new);
221 if (old_ofs != new_ofs)
222 return false;
223 break;
224 }
225
226 case Bytecodes::_iinc :
227 if (_s_old->is_wide() != _s_new->is_wide())
228 return false;
229 if (! _s_old->is_wide()) {
230 // We could use get_index_u1 and get_constant_u1, but it's simpler to grab both bytes at once:
231 if (Bytes::get_Java_u2(_s_old->bcp() + 1) != Bytes::get_Java_u2(_s_new->bcp() + 1))
232 return false;
233 } else {
234 // We could use get_index_u2 and get_constant_u2, but it's simpler to grab all four bytes at once:
235 if (Bytes::get_Java_u4(_s_old->bcp() + 1) != Bytes::get_Java_u4(_s_new->bcp() + 1))
236 return false;
237 }
238 break;
239
240 case Bytecodes::_goto_w : // fall through
241 case Bytecodes::_jsr_w : {
242 int old_ofs = _s_old->bytecode().get_offset_s4(c_old);
243 int new_ofs = _s_new->bytecode().get_offset_s4(c_new);
244 if (old_ofs != new_ofs)
245 return false;
246 break;
247 }
248
249 case Bytecodes::_lookupswitch : // fall through
250 case Bytecodes::_tableswitch : {
251 int len_old = _s_old->instruction_size();
252 int len_new = _s_new->instruction_size();
253 if (len_old != len_new)
254 return false;
255 if (memcmp(_s_old->bcp(), _s_new->bcp(), len_old) != 0)
256 return false;
257 break;
258 }
259
260 default:
261 break;
262 }
263
264 return true;
265 }
266
267 bool MethodComparator::pool_constants_same(int cpi_old, int cpi_new) {
268 constantTag tag_old = _old_cp->tag_at(cpi_old);
269 constantTag tag_new = _new_cp->tag_at(cpi_new);
270 if (tag_old.is_int() || tag_old.is_float()) {
271 if (tag_old.value() != tag_new.value())
272 return false;
273 if (tag_old.is_int()) {
274 if (_old_cp->int_at(cpi_old) != _new_cp->int_at(cpi_new))
275 return false;
276 } else {
277 // Use jint_cast to compare the bits rather than numerical values.
278 // This makes a difference for NaN constants.
279 if (jint_cast(_old_cp->float_at(cpi_old)) != jint_cast(_new_cp->float_at(cpi_new)))
280 return false;
281 }
282 } else if (tag_old.is_string() && tag_new.is_string()) {
283 if (strcmp(_old_cp->string_at_noresolve(cpi_old),
284 _new_cp->string_at_noresolve(cpi_new)) != 0)
285 return false;
286 if (_old_cp->is_pseudo_string_at(cpi_old) || _new_cp->is_pseudo_string_at(cpi_new))
287 return (_old_cp->is_pseudo_string_at(cpi_old) == _new_cp->is_pseudo_string_at(cpi_new));
288 } else if (tag_old.is_klass() || tag_old.is_unresolved_klass()) {
289 // tag_old should be klass - 4881222
290 if (! (tag_new.is_unresolved_klass() || tag_new.is_klass()))
291 return false;
292 if (_old_cp->klass_at_noresolve(cpi_old) !=
293 _new_cp->klass_at_noresolve(cpi_new))
294 return false;
295 } else if (tag_old.is_method_type() && tag_new.is_method_type()) {
296 int mti_old = _old_cp->method_type_index_at(cpi_old);
297 int mti_new = _new_cp->method_type_index_at(cpi_new);
298 if ((_old_cp->symbol_at(mti_old) != _new_cp->symbol_at(mti_new)))
299 return false;
300 } else if (tag_old.is_method_handle() && tag_new.is_method_handle()) {
301 if (_old_cp->method_handle_ref_kind_at(cpi_old) !=
302 _new_cp->method_handle_ref_kind_at(cpi_new))
303 return false;
304 int mhi_old = _old_cp->method_handle_index_at(cpi_old);
305 int mhi_new = _new_cp->method_handle_index_at(cpi_new);
306 if ((_old_cp->uncached_klass_ref_at_noresolve(mhi_old) != _new_cp->uncached_klass_ref_at_noresolve(mhi_new)) ||
307 (_old_cp->uncached_name_ref_at(mhi_old) != _new_cp->uncached_name_ref_at(mhi_new)) ||
308 (_old_cp->uncached_signature_ref_at(mhi_old) != _new_cp->uncached_signature_ref_at(mhi_new)))
309 return false;
310 } else {
311 return false; // unknown tag
312 }
313 return true;
314 }
315
316
317 int MethodComparator::check_stack_and_locals_size(Method* old_method, Method* new_method) {
318 if (old_method->max_stack() != new_method->max_stack()) {
319 return 1;
320 } else if (old_method->max_locals() != new_method->max_locals()) {
321 return 2;
322 } else if (old_method->size_of_parameters() != new_method->size_of_parameters()) {
323 return 3;
324 } else return 0;
325 }