1 /*
2 * Copyright (c) 2000, 2017, 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 "oops/oop.inline.hpp"
27 #include "oops/symbol.hpp"
28 #include "prims/methodComparator.hpp"
29 #include "runtime/handles.inline.hpp"
30 #include "utilities/globalDefinitions.hpp"
31
32 BytecodeStream *MethodComparator::_s_old;
33 BytecodeStream *MethodComparator::_s_new;
34 ConstantPool* MethodComparator::_old_cp;
35 ConstantPool* MethodComparator::_new_cp;
36
37 bool MethodComparator::methods_EMCP(Method* old_method, Method* new_method) {
38 if (old_method->code_size() != new_method->code_size())
39 return false;
40 if (check_stack_and_locals_size(old_method, new_method) != 0) {
41 if (log_is_enabled(Debug, redefine, class, methodcomparator)) {
42 ResourceMark rm;
43 log_debug(redefine, class, methodcomparator)
44 ("Methods %s non-comparable with diagnosis %d",
45 old_method->name()->as_C_string(), check_stack_and_locals_size(old_method, new_method));
46 }
47 return false;
48 }
49
50 _old_cp = old_method->constants();
51 _new_cp = new_method->constants();
52 BytecodeStream s_old(old_method);
53 BytecodeStream s_new(new_method);
54 _s_old = &s_old;
55 _s_new = &s_new;
56 Bytecodes::Code c_old, c_new;
57
58 while ((c_old = s_old.next()) >= 0) {
59 if ((c_new = s_new.next()) < 0 || c_old != c_new)
60 return false;
61
62 if (! args_same(c_old, c_new))
63 return false;
64 }
65 return true;
66 }
67
68 bool MethodComparator::args_same(Bytecodes::Code c_old, Bytecodes::Code c_new) {
69 // BytecodeStream returns the correct standard Java bytecodes for various "fast"
70 // bytecode versions, so we don't have to bother about them here..
71 switch (c_old) {
72 case Bytecodes::_new : // fall through
73 case Bytecodes::_anewarray : // fall through
74 case Bytecodes::_multianewarray : // fall through
75 case Bytecodes::_checkcast : // fall through
76 case Bytecodes::_instanceof : {
77 u2 cpi_old = _s_old->get_index_u2();
78 u2 cpi_new = _s_new->get_index_u2();
79 if ((_old_cp->klass_at_noresolve(cpi_old) != _new_cp->klass_at_noresolve(cpi_new)))
80 return false;
81 if (c_old == Bytecodes::_multianewarray &&
82 *(jbyte*)(_s_old->bcp() + 3) != *(jbyte*)(_s_new->bcp() + 3))
83 return false;
84 break;
85 }
86
87 case Bytecodes::_getstatic : // fall through
88 case Bytecodes::_putstatic : // fall through
89 case Bytecodes::_getfield : // fall through
90 case Bytecodes::_putfield : // fall through
91 case Bytecodes::_invokevirtual : // fall through
92 case Bytecodes::_invokespecial : // fall through
93 case Bytecodes::_invokestatic : // fall through
94 case Bytecodes::_invokeinterface : {
95 int cpci_old = _s_old->get_index_u2_cpcache();
96 int cpci_new = _s_new->get_index_u2_cpcache();
97 // Check if the names of classes, field/method names and signatures at these indexes
98 // are the same. Indices which are really into constantpool cache (rather than constant
99 // pool itself) are accepted by the constantpool query routines below.
100 if ((_old_cp->klass_ref_at_noresolve(cpci_old) != _new_cp->klass_ref_at_noresolve(cpci_new)) ||
101 (_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
102 (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
103 return false;
104 break;
105 }
106 case Bytecodes::_invokedynamic: {
107 int cpci_old = _s_old->get_index_u4();
108 int cpci_new = _s_new->get_index_u4();
109
110 // Check if the names of classes, field/method names and signatures at these indexes
111 // are the same. Indices which are really into constantpool cache (rather than constant
112 // pool itself) are accepted by the constantpool query routines below.
113 if ((_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
114 (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
115 return false;
116
117 // Translate object indexes to constant pool cache indexes.
118 cpci_old = _old_cp->invokedynamic_cp_cache_index(cpci_old);
119 cpci_new = _new_cp->invokedynamic_cp_cache_index(cpci_new);
120
121 int cpi_old = _old_cp->cache()->entry_at(cpci_old)->constant_pool_index();
122 int cpi_new = _new_cp->cache()->entry_at(cpci_new)->constant_pool_index();
123 int bsm_old = _old_cp->invoke_dynamic_bootstrap_method_ref_index_at(cpi_old);
124 int bsm_new = _new_cp->invoke_dynamic_bootstrap_method_ref_index_at(cpi_new);
125 if (!pool_constants_same(bsm_old, bsm_new))
126 return false;
127 int cnt_old = _old_cp->invoke_dynamic_argument_count_at(cpi_old);
128 int cnt_new = _new_cp->invoke_dynamic_argument_count_at(cpi_new);
129 if (cnt_old != cnt_new)
130 return false;
131 for (int arg_i = 0; arg_i < cnt_old; arg_i++) {
132 int idx_old = _old_cp->invoke_dynamic_argument_index_at(cpi_old, arg_i);
133 int idx_new = _new_cp->invoke_dynamic_argument_index_at(cpi_new, arg_i);
134 if (!pool_constants_same(idx_old, idx_new))
135 return false;
136 }
137 break;
138 }
139
140 case Bytecodes::_ldc : // fall through
141 case Bytecodes::_ldc_w : {
142 Bytecode_loadconstant ldc_old(_s_old->method(), _s_old->bci());
143 Bytecode_loadconstant ldc_new(_s_new->method(), _s_new->bci());
144 int cpi_old = ldc_old.pool_index();
145 int cpi_new = ldc_new.pool_index();
146 if (!pool_constants_same(cpi_old, cpi_new))
147 return false;
148 break;
149 }
150
151 case Bytecodes::_ldc2_w : {
152 u2 cpi_old = _s_old->get_index_u2();
153 u2 cpi_new = _s_new->get_index_u2();
154 constantTag tag_old = _old_cp->tag_at(cpi_old);
155 constantTag tag_new = _new_cp->tag_at(cpi_new);
156 if (tag_old.value() != tag_new.value())
157 return false;
158 if (tag_old.is_long()) {
159 if (_old_cp->long_at(cpi_old) != _new_cp->long_at(cpi_new))
160 return false;
161 } else {
162 // Use jlong_cast to compare the bits rather than numerical values.
163 // This makes a difference for NaN constants.
164 if (jlong_cast(_old_cp->double_at(cpi_old)) != jlong_cast(_new_cp->double_at(cpi_new)))
165 return false;
166 }
167 break;
168 }
169
170 case Bytecodes::_bipush :
171 if (_s_old->bcp()[1] != _s_new->bcp()[1])
172 return false;
173 break;
174
175 case Bytecodes::_sipush :
176 if (_s_old->get_index_u2() != _s_new->get_index_u2())
177 return false;
178 break;
179
180 case Bytecodes::_aload : // fall through
181 case Bytecodes::_astore : // fall through
182 case Bytecodes::_dload : // fall through
183 case Bytecodes::_dstore : // fall through
184 case Bytecodes::_fload : // fall through
185 case Bytecodes::_fstore : // fall through
186 case Bytecodes::_iload : // fall through
187 case Bytecodes::_istore : // fall through
188 case Bytecodes::_lload : // fall through
189 case Bytecodes::_lstore : // fall through
190 case Bytecodes::_ret :
191 if (_s_old->is_wide() != _s_new->is_wide())
192 return false;
193 if (_s_old->get_index() != _s_new->get_index())
194 return false;
195 break;
196
197 case Bytecodes::_goto : // fall through
198 case Bytecodes::_if_acmpeq : // fall through
199 case Bytecodes::_if_acmpne : // fall through
200 case Bytecodes::_if_icmpeq : // fall through
201 case Bytecodes::_if_icmpne : // fall through
202 case Bytecodes::_if_icmplt : // fall through
203 case Bytecodes::_if_icmpge : // fall through
204 case Bytecodes::_if_icmpgt : // fall through
205 case Bytecodes::_if_icmple : // fall through
206 case Bytecodes::_ifeq : // fall through
207 case Bytecodes::_ifne : // fall through
208 case Bytecodes::_iflt : // fall through
209 case Bytecodes::_ifge : // fall through
210 case Bytecodes::_ifgt : // fall through
211 case Bytecodes::_ifle : // fall through
212 case Bytecodes::_ifnonnull : // fall through
213 case Bytecodes::_ifnull : // fall through
214 case Bytecodes::_jsr : {
215 int old_ofs = _s_old->bytecode().get_offset_s2(c_old);
216 int new_ofs = _s_new->bytecode().get_offset_s2(c_new);
217 if (old_ofs != new_ofs)
218 return false;
219 break;
220 }
221
222 case Bytecodes::_iinc :
223 if (_s_old->is_wide() != _s_new->is_wide())
224 return false;
225 if (! _s_old->is_wide()) {
226 // We could use get_index_u1 and get_constant_u1, but it's simpler to grab both bytes at once:
227 if (Bytes::get_Java_u2(_s_old->bcp() + 1) != Bytes::get_Java_u2(_s_new->bcp() + 1))
228 return false;
229 } else {
230 // We could use get_index_u2 and get_constant_u2, but it's simpler to grab all four bytes at once:
231 if (Bytes::get_Java_u4(_s_old->bcp() + 1) != Bytes::get_Java_u4(_s_new->bcp() + 1))
232 return false;
233 }
234 break;
235
236 case Bytecodes::_goto_w : // fall through
237 case Bytecodes::_jsr_w : {
238 int old_ofs = _s_old->bytecode().get_offset_s4(c_old);
239 int new_ofs = _s_new->bytecode().get_offset_s4(c_new);
240 if (old_ofs != new_ofs)
241 return false;
242 break;
243 }
244
245 case Bytecodes::_lookupswitch : // fall through
246 case Bytecodes::_tableswitch : {
247 int len_old = _s_old->instruction_size();
248 int len_new = _s_new->instruction_size();
249 if (len_old != len_new)
250 return false;
251 if (memcmp(_s_old->bcp(), _s_new->bcp(), len_old) != 0)
252 return false;
253 break;
254 }
255
256 default:
257 break;
258 }
259
260 return true;
261 }
262
263 bool MethodComparator::pool_constants_same(int cpi_old, int cpi_new) {
264 constantTag tag_old = _old_cp->tag_at(cpi_old);
265 constantTag tag_new = _new_cp->tag_at(cpi_new);
266 if (tag_old.is_int() || tag_old.is_float()) {
267 if (tag_old.value() != tag_new.value())
268 return false;
269 if (tag_old.is_int()) {
270 if (_old_cp->int_at(cpi_old) != _new_cp->int_at(cpi_new))
271 return false;
272 } else {
273 // Use jint_cast to compare the bits rather than numerical values.
274 // This makes a difference for NaN constants.
275 if (jint_cast(_old_cp->float_at(cpi_old)) != jint_cast(_new_cp->float_at(cpi_new)))
276 return false;
277 }
278 } else if (tag_old.is_string() && tag_new.is_string()) {
279 if (strcmp(_old_cp->string_at_noresolve(cpi_old),
280 _new_cp->string_at_noresolve(cpi_new)) != 0)
281 return false;
282 if (_old_cp->is_pseudo_string_at(cpi_old) || _new_cp->is_pseudo_string_at(cpi_new))
283 return (_old_cp->is_pseudo_string_at(cpi_old) == _new_cp->is_pseudo_string_at(cpi_new));
284 } else if (tag_old.is_klass() || tag_old.is_unresolved_klass()) {
285 // tag_old should be klass - 4881222
286 if (! (tag_new.is_unresolved_klass() || tag_new.is_klass()))
287 return false;
288 if (_old_cp->klass_at_noresolve(cpi_old) !=
289 _new_cp->klass_at_noresolve(cpi_new))
290 return false;
291 } else if (tag_old.is_method_type() && tag_new.is_method_type()) {
292 int mti_old = _old_cp->method_type_index_at(cpi_old);
293 int mti_new = _new_cp->method_type_index_at(cpi_new);
294 if ((_old_cp->symbol_at(mti_old) != _new_cp->symbol_at(mti_new)))
295 return false;
296 } else if (tag_old.is_method_handle() && tag_new.is_method_handle()) {
297 if (_old_cp->method_handle_ref_kind_at(cpi_old) !=
298 _new_cp->method_handle_ref_kind_at(cpi_new))
299 return false;
300 int mhi_old = _old_cp->method_handle_index_at(cpi_old);
301 int mhi_new = _new_cp->method_handle_index_at(cpi_new);
302 if ((_old_cp->uncached_klass_ref_at_noresolve(mhi_old) != _new_cp->uncached_klass_ref_at_noresolve(mhi_new)) ||
303 (_old_cp->uncached_name_ref_at(mhi_old) != _new_cp->uncached_name_ref_at(mhi_new)) ||
304 (_old_cp->uncached_signature_ref_at(mhi_old) != _new_cp->uncached_signature_ref_at(mhi_new)))
305 return false;
306 } else {
307 return false; // unknown tag
308 }
309 return true;
310 }
311
312
313 int MethodComparator::check_stack_and_locals_size(Method* old_method, Method* new_method) {
314 if (old_method->max_stack() != new_method->max_stack()) {
315 return 1;
316 } else if (old_method->max_locals() != new_method->max_locals()) {
317 return 2;
318 } else if (old_method->size_of_parameters() != new_method->size_of_parameters()) {
319 return 3;
320 } else return 0;
321 }