1 /*
2 * Copyright (c) 2000, 2018, 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 "memory/resourceArea.hpp"
27 #include "oops/constantPool.inline.hpp"
28 #include "oops/oop.inline.hpp"
29 #include "oops/symbol.hpp"
30 #include "prims/methodComparator.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "utilities/globalDefinitions.hpp"
33
34 BytecodeStream *MethodComparator::_s_old;
35 BytecodeStream *MethodComparator::_s_new;
36 ConstantPool* MethodComparator::_old_cp;
37 ConstantPool* MethodComparator::_new_cp;
38
39 bool MethodComparator::methods_EMCP(Method* old_method, Method* new_method) {
40 if (old_method->code_size() != new_method->code_size())
41 return false;
42 if (check_stack_and_locals_size(old_method, new_method) != 0) {
43 if (log_is_enabled(Debug, redefine, class, methodcomparator)) {
44 ResourceMark rm;
45 log_debug(redefine, class, methodcomparator)
46 ("Methods %s non-comparable with diagnosis %d",
47 old_method->name()->as_C_string(), check_stack_and_locals_size(old_method, new_method));
48 }
49 return false;
50 }
51
52 _old_cp = old_method->constants();
53 _new_cp = new_method->constants();
54 BytecodeStream s_old(old_method);
55 BytecodeStream s_new(new_method);
56 _s_old = &s_old;
57 _s_new = &s_new;
58 Bytecodes::Code c_old, c_new;
59
60 while ((c_old = s_old.next()) >= 0) {
61 if ((c_new = s_new.next()) < 0 || c_old != c_new)
62 return false;
63
64 if (! args_same(c_old, c_new))
65 return false;
66 }
67 return true;
68 }
69
70 bool MethodComparator::args_same(Bytecodes::Code c_old, Bytecodes::Code c_new) {
71 // BytecodeStream returns the correct standard Java bytecodes for various "fast"
72 // bytecode versions, so we don't have to bother about them here..
73 switch (c_old) {
74 case Bytecodes::_new : // fall through
75 case Bytecodes::_anewarray : // fall through
76 case Bytecodes::_multianewarray : // fall through
77 case Bytecodes::_checkcast : // fall through
78 case Bytecodes::_instanceof : {
79 u2 cpi_old = _s_old->get_index_u2();
80 u2 cpi_new = _s_new->get_index_u2();
81 if ((_old_cp->klass_at_noresolve(cpi_old) != _new_cp->klass_at_noresolve(cpi_new)))
82 return false;
83 if (c_old == Bytecodes::_multianewarray &&
84 *(jbyte*)(_s_old->bcp() + 3) != *(jbyte*)(_s_new->bcp() + 3))
85 return false;
86 break;
87 }
88
89 case Bytecodes::_getstatic : // fall through
90 case Bytecodes::_putstatic : // fall through
91 case Bytecodes::_getfield : // fall through
92 case Bytecodes::_putfield : // fall through
93 case Bytecodes::_invokevirtual : // fall through
94 case Bytecodes::_invokespecial : // fall through
95 case Bytecodes::_invokestatic : // fall through
96 case Bytecodes::_invokeinterface : {
97 int cpci_old = _s_old->get_index_u2_cpcache();
98 int cpci_new = _s_new->get_index_u2_cpcache();
99 // Check if the names of classes, field/method names and signatures at these indexes
100 // are the same. Indices which are really into constantpool cache (rather than constant
101 // pool itself) are accepted by the constantpool query routines below.
102 if ((_old_cp->klass_ref_at_noresolve(cpci_old) != _new_cp->klass_ref_at_noresolve(cpci_new)) ||
103 (_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
104 (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
105 return false;
106 break;
107 }
108 case Bytecodes::_invokedynamic: {
109 int cpci_old = _s_old->get_index_u4();
110 int cpci_new = _s_new->get_index_u4();
111
112 // Check if the names of classes, field/method names and signatures at these indexes
113 // are the same. Indices which are really into constantpool cache (rather than constant
114 // pool itself) are accepted by the constantpool query routines below.
115 if ((_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
116 (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
117 return false;
118
119 // Translate object indexes to constant pool cache indexes.
120 cpci_old = _old_cp->invokedynamic_cp_cache_index(cpci_old);
121 cpci_new = _new_cp->invokedynamic_cp_cache_index(cpci_new);
122
123 int cpi_old = _old_cp->cache()->entry_at(cpci_old)->constant_pool_index();
124 int cpi_new = _new_cp->cache()->entry_at(cpci_new)->constant_pool_index();
125 int bsm_old = _old_cp->invoke_dynamic_bootstrap_method_ref_index_at(cpi_old);
126 int bsm_new = _new_cp->invoke_dynamic_bootstrap_method_ref_index_at(cpi_new);
127 if (!pool_constants_same(bsm_old, bsm_new))
128 return false;
129 int cnt_old = _old_cp->invoke_dynamic_argument_count_at(cpi_old);
130 int cnt_new = _new_cp->invoke_dynamic_argument_count_at(cpi_new);
131 if (cnt_old != cnt_new)
132 return false;
133 for (int arg_i = 0; arg_i < cnt_old; arg_i++) {
134 int idx_old = _old_cp->invoke_dynamic_argument_index_at(cpi_old, arg_i);
135 int idx_new = _new_cp->invoke_dynamic_argument_index_at(cpi_new, arg_i);
136 if (!pool_constants_same(idx_old, idx_new))
137 return false;
138 }
139 break;
140 }
141
142 case Bytecodes::_ldc : // fall through
143 case Bytecodes::_ldc_w : {
144 Bytecode_loadconstant ldc_old(_s_old->method(), _s_old->bci());
145 Bytecode_loadconstant ldc_new(_s_new->method(), _s_new->bci());
146 int cpi_old = ldc_old.pool_index();
147 int cpi_new = ldc_new.pool_index();
148 if (!pool_constants_same(cpi_old, cpi_new))
149 return false;
150 break;
151 }
152
153 case Bytecodes::_ldc2_w : {
154 u2 cpi_old = _s_old->get_index_u2();
155 u2 cpi_new = _s_new->get_index_u2();
156 constantTag tag_old = _old_cp->tag_at(cpi_old);
157 constantTag tag_new = _new_cp->tag_at(cpi_new);
158 if (tag_old.value() != tag_new.value())
159 return false;
160 if (tag_old.is_long()) {
161 if (_old_cp->long_at(cpi_old) != _new_cp->long_at(cpi_new))
162 return false;
163 } else {
164 // Use jlong_cast to compare the bits rather than numerical values.
165 // This makes a difference for NaN constants.
166 if (jlong_cast(_old_cp->double_at(cpi_old)) != jlong_cast(_new_cp->double_at(cpi_new)))
167 return false;
168 }
169 break;
170 }
171
172 case Bytecodes::_bipush :
173 if (_s_old->bcp()[1] != _s_new->bcp()[1])
174 return false;
175 break;
176
177 case Bytecodes::_sipush :
178 if (_s_old->get_index_u2() != _s_new->get_index_u2())
179 return false;
180 break;
181
182 case Bytecodes::_aload : // fall through
183 case Bytecodes::_astore : // fall through
184 case Bytecodes::_dload : // fall through
185 case Bytecodes::_dstore : // fall through
186 case Bytecodes::_fload : // fall through
187 case Bytecodes::_fstore : // fall through
188 case Bytecodes::_iload : // fall through
189 case Bytecodes::_istore : // fall through
190 case Bytecodes::_lload : // fall through
191 case Bytecodes::_lstore : // fall through
192 case Bytecodes::_ret :
193 if (_s_old->is_wide() != _s_new->is_wide())
194 return false;
195 if (_s_old->get_index() != _s_new->get_index())
196 return false;
197 break;
198
199 case Bytecodes::_goto : // fall through
200 case Bytecodes::_if_acmpeq : // fall through
201 case Bytecodes::_if_acmpne : // fall through
202 case Bytecodes::_if_icmpeq : // fall through
203 case Bytecodes::_if_icmpne : // fall through
204 case Bytecodes::_if_icmplt : // fall through
205 case Bytecodes::_if_icmpge : // fall through
206 case Bytecodes::_if_icmpgt : // fall through
207 case Bytecodes::_if_icmple : // fall through
208 case Bytecodes::_ifeq : // fall through
209 case Bytecodes::_ifne : // fall through
210 case Bytecodes::_iflt : // fall through
211 case Bytecodes::_ifge : // fall through
212 case Bytecodes::_ifgt : // fall through
213 case Bytecodes::_ifle : // fall through
214 case Bytecodes::_ifnonnull : // fall through
215 case Bytecodes::_ifnull : // fall through
216 case Bytecodes::_jsr : {
217 int old_ofs = _s_old->bytecode().get_offset_s2(c_old);
218 int new_ofs = _s_new->bytecode().get_offset_s2(c_new);
219 if (old_ofs != new_ofs)
220 return false;
221 break;
222 }
223
224 case Bytecodes::_iinc :
225 if (_s_old->is_wide() != _s_new->is_wide())
226 return false;
227 if (! _s_old->is_wide()) {
228 // We could use get_index_u1 and get_constant_u1, but it's simpler to grab both bytes at once:
229 if (Bytes::get_Java_u2(_s_old->bcp() + 1) != Bytes::get_Java_u2(_s_new->bcp() + 1))
230 return false;
231 } else {
232 // We could use get_index_u2 and get_constant_u2, but it's simpler to grab all four bytes at once:
233 if (Bytes::get_Java_u4(_s_old->bcp() + 1) != Bytes::get_Java_u4(_s_new->bcp() + 1))
234 return false;
235 }
236 break;
237
238 case Bytecodes::_goto_w : // fall through
239 case Bytecodes::_jsr_w : {
240 int old_ofs = _s_old->bytecode().get_offset_s4(c_old);
241 int new_ofs = _s_new->bytecode().get_offset_s4(c_new);
242 if (old_ofs != new_ofs)
243 return false;
244 break;
245 }
246
247 case Bytecodes::_lookupswitch : // fall through
248 case Bytecodes::_tableswitch : {
249 int len_old = _s_old->instruction_size();
250 int len_new = _s_new->instruction_size();
251 if (len_old != len_new)
252 return false;
253 if (memcmp(_s_old->bcp(), _s_new->bcp(), len_old) != 0)
254 return false;
255 break;
256 }
257
258 default:
259 break;
260 }
261
262 return true;
263 }
264
265 bool MethodComparator::pool_constants_same(int cpi_old, int cpi_new) {
266 constantTag tag_old = _old_cp->tag_at(cpi_old);
267 constantTag tag_new = _new_cp->tag_at(cpi_new);
268 if (tag_old.is_int() || tag_old.is_float()) {
269 if (tag_old.value() != tag_new.value())
270 return false;
271 if (tag_old.is_int()) {
272 if (_old_cp->int_at(cpi_old) != _new_cp->int_at(cpi_new))
273 return false;
274 } else {
275 // Use jint_cast to compare the bits rather than numerical values.
276 // This makes a difference for NaN constants.
277 if (jint_cast(_old_cp->float_at(cpi_old)) != jint_cast(_new_cp->float_at(cpi_new)))
278 return false;
279 }
280 } else if (tag_old.is_string() && tag_new.is_string()) {
281 if (strcmp(_old_cp->string_at_noresolve(cpi_old),
282 _new_cp->string_at_noresolve(cpi_new)) != 0)
283 return false;
284 if (_old_cp->is_pseudo_string_at(cpi_old) || _new_cp->is_pseudo_string_at(cpi_new))
285 return (_old_cp->is_pseudo_string_at(cpi_old) == _new_cp->is_pseudo_string_at(cpi_new));
286 } else if (tag_old.is_klass() || tag_old.is_unresolved_klass()) {
287 // tag_old should be klass - 4881222
288 if (! (tag_new.is_unresolved_klass() || tag_new.is_klass()))
289 return false;
290 if (_old_cp->klass_at_noresolve(cpi_old) !=
291 _new_cp->klass_at_noresolve(cpi_new))
292 return false;
293 } else if (tag_old.is_method_type() && tag_new.is_method_type()) {
294 int mti_old = _old_cp->method_type_index_at(cpi_old);
295 int mti_new = _new_cp->method_type_index_at(cpi_new);
296 if ((_old_cp->symbol_at(mti_old) != _new_cp->symbol_at(mti_new)))
297 return false;
298 } else if (tag_old.is_method_handle() && tag_new.is_method_handle()) {
299 if (_old_cp->method_handle_ref_kind_at(cpi_old) !=
300 _new_cp->method_handle_ref_kind_at(cpi_new))
301 return false;
302 int mhi_old = _old_cp->method_handle_index_at(cpi_old);
303 int mhi_new = _new_cp->method_handle_index_at(cpi_new);
304 if ((_old_cp->uncached_klass_ref_at_noresolve(mhi_old) != _new_cp->uncached_klass_ref_at_noresolve(mhi_new)) ||
305 (_old_cp->uncached_name_ref_at(mhi_old) != _new_cp->uncached_name_ref_at(mhi_new)) ||
306 (_old_cp->uncached_signature_ref_at(mhi_old) != _new_cp->uncached_signature_ref_at(mhi_new)))
307 return false;
308 } else {
309 return false; // unknown tag
310 }
311 return true;
312 }
313
314
315 int MethodComparator::check_stack_and_locals_size(Method* old_method, Method* new_method) {
316 if (old_method->max_stack() != new_method->max_stack()) {
317 return 1;
318 } else if (old_method->max_locals() != new_method->max_locals()) {
319 return 2;
320 } else if (old_method->size_of_parameters() != new_method->size_of_parameters()) {
321 return 3;
322 } else return 0;
323 }