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