1 /*
2 * Copyright (c) 2000, 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 "incls/_precompiled.incl"
26 # include "incls/_methodComparator.cpp.incl"
27
28 BytecodeStream *MethodComparator::_s_old;
29 BytecodeStream *MethodComparator::_s_new;
30 constantPoolOop MethodComparator::_old_cp;
31 constantPoolOop MethodComparator::_new_cp;
32 BciMap *MethodComparator::_bci_map;
33 bool MethodComparator::_switchable_test;
34 GrowableArray<int> *MethodComparator::_fwd_jmps;
35
36 bool MethodComparator::methods_EMCP(methodOop old_method, methodOop new_method) {
37 if (old_method->code_size() != new_method->code_size())
38 return false;
39 if (check_stack_and_locals_size(old_method, new_method) != 0) {
40 // RC_TRACE macro has an embedded ResourceMark
41 RC_TRACE(0x00800000, ("Methods %s non-comparable with diagnosis %d",
42 old_method->name()->as_C_string(),
43 check_stack_and_locals_size(old_method, new_method)));
44 return false;
45 }
46
47 _old_cp = old_method->constants();
48 _new_cp = new_method->constants();
49 BytecodeStream s_old(old_method);
50 BytecodeStream s_new(new_method);
51 _s_old = &s_old;
52 _s_new = &s_new;
53 _switchable_test = false;
54 Bytecodes::Code c_old, c_new;
55
56 while ((c_old = s_old.next()) >= 0) {
57 if ((c_new = s_new.next()) < 0 || c_old != c_new)
58 return false;
59
60 if (! args_same(c_old, c_new))
61 return false;
62 }
63 return true;
64 }
65
66
67 bool MethodComparator::methods_switchable(methodOop old_method, methodOop new_method,
68 BciMap &bci_map) {
69 if (old_method->code_size() > new_method->code_size())
70 // Something has definitely been deleted in the new method, compared to the old one.
71 return false;
72
73 if (! check_stack_and_locals_size(old_method, new_method))
74 return false;
75
76 _old_cp = old_method->constants();
77 _new_cp = new_method->constants();
78 BytecodeStream s_old(old_method);
79 BytecodeStream s_new(new_method);
80 _s_old = &s_old;
81 _s_new = &s_new;
82 _bci_map = &bci_map;
83 _switchable_test = true;
84 GrowableArray<int> fwd_jmps(16);
85 _fwd_jmps = &fwd_jmps;
86 Bytecodes::Code c_old, c_new;
87
88 while ((c_old = s_old.next()) >= 0) {
89 if ((c_new = s_new.next()) < 0)
90 return false;
91 if (! (c_old == c_new && args_same(c_old, c_new))) {
92 int old_bci = s_old.bci();
93 int new_st_bci = s_new.bci();
94 bool found_match = false;
95 do {
96 c_new = s_new.next();
97 if (c_new == c_old && args_same(c_old, c_new)) {
98 found_match = true;
99 break;
100 }
101 } while (c_new >= 0);
102 if (! found_match)
103 return false;
104 int new_end_bci = s_new.bci();
105 bci_map.store_fragment_location(old_bci, new_st_bci, new_end_bci);
106 }
107 }
108
109 // Now we can test all forward jumps
110 for (int i = 0; i < fwd_jmps.length() / 2; i++) {
111 if (! bci_map.old_and_new_locations_same(fwd_jmps.at(i*2), fwd_jmps.at(i*2+1))) {
112 RC_TRACE(0x00800000,
113 ("Fwd jump miss: old dest = %d, calc new dest = %d, act new dest = %d",
114 fwd_jmps.at(i*2), bci_map.new_bci_for_old(fwd_jmps.at(i*2)),
115 fwd_jmps.at(i*2+1)));
116 return false;
117 }
118 }
119
120 return true;
121 }
122
123
124 bool MethodComparator::args_same(Bytecodes::Code c_old, Bytecodes::Code c_new) {
125 // BytecodeStream returns the correct standard Java bytecodes for various "fast"
126 // bytecode versions, so we don't have to bother about them here..
127 switch (c_old) {
128 case Bytecodes::_new : // fall through
129 case Bytecodes::_anewarray : // fall through
130 case Bytecodes::_multianewarray : // fall through
131 case Bytecodes::_checkcast : // fall through
132 case Bytecodes::_instanceof : {
133 u2 cpi_old = _s_old->get_index_u2();
134 u2 cpi_new = _s_new->get_index_u2();
135 if ((_old_cp->klass_at_noresolve(cpi_old) != _new_cp->klass_at_noresolve(cpi_new)))
136 return false;
137 if (c_old == Bytecodes::_multianewarray &&
138 *(jbyte*)(_s_old->bcp() + 3) != *(jbyte*)(_s_new->bcp() + 3))
139 return false;
140 break;
141 }
142
143 case Bytecodes::_getstatic : // fall through
144 case Bytecodes::_putstatic : // fall through
145 case Bytecodes::_getfield : // fall through
146 case Bytecodes::_putfield : // fall through
147 case Bytecodes::_invokevirtual : // fall through
148 case Bytecodes::_invokespecial : // fall through
149 case Bytecodes::_invokestatic : // fall through
150 case Bytecodes::_invokedynamic : // fall through
151 case Bytecodes::_invokeinterface : {
152 int cpci_old = _s_old->has_index_u4() ? _s_old->get_index_u4() : _s_old->get_index_u2_cpcache();
153 int cpci_new = _s_new->has_index_u4() ? _s_new->get_index_u4() : _s_new->get_index_u2_cpcache();
154 // Check if the names of classes, field/method names and signatures at these indexes
155 // are the same. Indices which are really into constantpool cache (rather than constant
156 // pool itself) are accepted by the constantpool query routines below.
157 if ((_old_cp->klass_ref_at_noresolve(cpci_old) != _new_cp->klass_ref_at_noresolve(cpci_new)) ||
158 (_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
159 (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
160 return false;
161 break;
162 }
163
164 case Bytecodes::_ldc : // fall through
165 case Bytecodes::_ldc_w : {
166 Bytecode_loadconstant* ldc_old = Bytecode_loadconstant_at(_s_old->method(), _s_old->bci());
167 Bytecode_loadconstant* ldc_new = Bytecode_loadconstant_at(_s_new->method(), _s_new->bci());
168 int cpi_old = ldc_old->pool_index();
169 int cpi_new = ldc_new->pool_index();
170 constantTag tag_old = _old_cp->tag_at(cpi_old);
171 constantTag tag_new = _new_cp->tag_at(cpi_new);
172 if (tag_old.is_int() || tag_old.is_float()) {
173 if (tag_old.value() != tag_new.value())
174 return false;
175 if (tag_old.is_int()) {
176 if (_old_cp->int_at(cpi_old) != _new_cp->int_at(cpi_new))
177 return false;
178 } else {
179 // Use jint_cast to compare the bits rather than numerical values.
180 // This makes a difference for NaN constants.
181 if (jint_cast(_old_cp->float_at(cpi_old)) != jint_cast(_new_cp->float_at(cpi_new)))
182 return false;
183 }
184 } else if (tag_old.is_string() || tag_old.is_unresolved_string()) {
185 if (! (tag_new.is_unresolved_string() || tag_new.is_string()))
186 return false;
187 if (strcmp(_old_cp->string_at_noresolve(cpi_old),
188 _new_cp->string_at_noresolve(cpi_new)) != 0)
189 return false;
190 } else if (tag_old.is_klass() || tag_old.is_unresolved_klass()) {
191 // tag_old should be klass - 4881222
192 if (! (tag_new.is_unresolved_klass() || tag_new.is_klass()))
193 return false;
194 if (_old_cp->klass_at_noresolve(cpi_old) !=
195 _new_cp->klass_at_noresolve(cpi_new))
196 return false;
197 } else if (tag_old.is_method_type() && tag_new.is_method_type()) {
198 int mti_old = _old_cp->method_type_index_at(cpi_old);
199 int mti_new = _new_cp->method_type_index_at(cpi_new);
200 if ((_old_cp->symbol_at(mti_old) != _new_cp->symbol_at(mti_new)))
201 return false;
202 } else if (tag_old.is_method_handle() && tag_new.is_method_handle()) {
203 if (_old_cp->method_handle_ref_kind_at(cpi_old) !=
204 _new_cp->method_handle_ref_kind_at(cpi_new))
205 return false;
206 int mhi_old = _old_cp->method_handle_index_at(cpi_old);
207 int mhi_new = _new_cp->method_handle_index_at(cpi_new);
208 if ((_old_cp->uncached_klass_ref_at_noresolve(mhi_old) != _new_cp->uncached_klass_ref_at_noresolve(mhi_new)) ||
209 (_old_cp->uncached_name_ref_at(mhi_old) != _new_cp->uncached_name_ref_at(mhi_new)) ||
210 (_old_cp->uncached_signature_ref_at(mhi_old) != _new_cp->uncached_signature_ref_at(mhi_new)))
211 return false;
212 } else {
213 return false; // unknown tag
214 }
215 break;
216 }
217
218 case Bytecodes::_ldc2_w : {
219 u2 cpi_old = _s_old->get_index_u2();
220 u2 cpi_new = _s_new->get_index_u2();
221 constantTag tag_old = _old_cp->tag_at(cpi_old);
222 constantTag tag_new = _new_cp->tag_at(cpi_new);
223 if (tag_old.value() != tag_new.value())
224 return false;
225 if (tag_old.is_long()) {
226 if (_old_cp->long_at(cpi_old) != _new_cp->long_at(cpi_new))
227 return false;
228 } else {
229 // Use jlong_cast to compare the bits rather than numerical values.
230 // This makes a difference for NaN constants.
231 if (jlong_cast(_old_cp->double_at(cpi_old)) != jlong_cast(_new_cp->double_at(cpi_new)))
232 return false;
233 }
234 break;
235 }
236
237 case Bytecodes::_bipush :
238 if (_s_old->bcp()[1] != _s_new->bcp()[1])
239 return false;
240 break;
241
242 case Bytecodes::_sipush :
243 if (_s_old->get_index_u2() != _s_new->get_index_u2())
244 return false;
245 break;
246
247 case Bytecodes::_aload : // fall through
248 case Bytecodes::_astore : // fall through
249 case Bytecodes::_dload : // fall through
250 case Bytecodes::_dstore : // fall through
251 case Bytecodes::_fload : // fall through
252 case Bytecodes::_fstore : // fall through
253 case Bytecodes::_iload : // fall through
254 case Bytecodes::_istore : // fall through
255 case Bytecodes::_lload : // fall through
256 case Bytecodes::_lstore : // fall through
257 case Bytecodes::_ret :
258 if (_s_old->is_wide() != _s_new->is_wide())
259 return false;
260 if (_s_old->get_index() != _s_new->get_index())
261 return false;
262 break;
263
264 case Bytecodes::_goto : // fall through
265 case Bytecodes::_if_acmpeq : // fall through
266 case Bytecodes::_if_acmpne : // fall through
267 case Bytecodes::_if_icmpeq : // fall through
268 case Bytecodes::_if_icmpne : // fall through
269 case Bytecodes::_if_icmplt : // fall through
270 case Bytecodes::_if_icmpge : // fall through
271 case Bytecodes::_if_icmpgt : // fall through
272 case Bytecodes::_if_icmple : // fall through
273 case Bytecodes::_ifeq : // fall through
274 case Bytecodes::_ifne : // fall through
275 case Bytecodes::_iflt : // fall through
276 case Bytecodes::_ifge : // fall through
277 case Bytecodes::_ifgt : // fall through
278 case Bytecodes::_ifle : // fall through
279 case Bytecodes::_ifnonnull : // fall through
280 case Bytecodes::_ifnull : // fall through
281 case Bytecodes::_jsr : {
282 int old_ofs = _s_old->bytecode()->get_offset_s2(c_old);
283 int new_ofs = _s_new->bytecode()->get_offset_s2(c_new);
284 if (_switchable_test) {
285 int old_dest = _s_old->bci() + old_ofs;
286 int new_dest = _s_new->bci() + new_ofs;
287 if (old_ofs < 0 && new_ofs < 0) {
288 if (! _bci_map->old_and_new_locations_same(old_dest, new_dest))
289 return false;
290 } else if (old_ofs > 0 && new_ofs > 0) {
291 _fwd_jmps->append(old_dest);
292 _fwd_jmps->append(new_dest);
293 } else {
294 return false;
295 }
296 } else {
297 if (old_ofs != new_ofs)
298 return false;
299 }
300 break;
301 }
302
303 case Bytecodes::_iinc :
304 if (_s_old->is_wide() != _s_new->is_wide())
305 return false;
306 if (! _s_old->is_wide()) {
307 // We could use get_index_u1 and get_constant_u1, but it's simpler to grab both bytes at once:
308 if (Bytes::get_Java_u2(_s_old->bcp() + 1) != Bytes::get_Java_u2(_s_new->bcp() + 1))
309 return false;
310 } else {
311 // We could use get_index_u2 and get_constant_u2, but it's simpler to grab all four bytes at once:
312 if (Bytes::get_Java_u4(_s_old->bcp() + 1) != Bytes::get_Java_u4(_s_new->bcp() + 1))
313 return false;
314 }
315 break;
316
317 case Bytecodes::_goto_w : // fall through
318 case Bytecodes::_jsr_w : {
319 int old_ofs = _s_old->bytecode()->get_offset_s4(c_old);
320 int new_ofs = _s_new->bytecode()->get_offset_s4(c_new);
321 if (_switchable_test) {
322 int old_dest = _s_old->bci() + old_ofs;
323 int new_dest = _s_new->bci() + new_ofs;
324 if (old_ofs < 0 && new_ofs < 0) {
325 if (! _bci_map->old_and_new_locations_same(old_dest, new_dest))
326 return false;
327 } else if (old_ofs > 0 && new_ofs > 0) {
328 _fwd_jmps->append(old_dest);
329 _fwd_jmps->append(new_dest);
330 } else {
331 return false;
332 }
333 } else {
334 if (old_ofs != new_ofs)
335 return false;
336 }
337 break;
338 }
339
340 case Bytecodes::_lookupswitch : // fall through
341 case Bytecodes::_tableswitch : {
342 if (_switchable_test) {
343 address aligned_bcp_old = (address) round_to((intptr_t)_s_old->bcp() + 1, jintSize);
344 address aligned_bcp_new = (address) round_to((intptr_t)_s_new->bcp() + 1, jintSize);
345 int default_old = (int) Bytes::get_Java_u4(aligned_bcp_old);
346 int default_new = (int) Bytes::get_Java_u4(aligned_bcp_new);
347 _fwd_jmps->append(_s_old->bci() + default_old);
348 _fwd_jmps->append(_s_new->bci() + default_new);
349 if (c_old == Bytecodes::_lookupswitch) {
350 int npairs_old = (int) Bytes::get_Java_u4(aligned_bcp_old + jintSize);
351 int npairs_new = (int) Bytes::get_Java_u4(aligned_bcp_new + jintSize);
352 if (npairs_old != npairs_new)
353 return false;
354 for (int i = 0; i < npairs_old; i++) {
355 int match_old = (int) Bytes::get_Java_u4(aligned_bcp_old + (2+2*i)*jintSize);
356 int match_new = (int) Bytes::get_Java_u4(aligned_bcp_new + (2+2*i)*jintSize);
357 if (match_old != match_new)
358 return false;
359 int ofs_old = (int) Bytes::get_Java_u4(aligned_bcp_old + (2+2*i+1)*jintSize);
360 int ofs_new = (int) Bytes::get_Java_u4(aligned_bcp_new + (2+2*i+1)*jintSize);
361 _fwd_jmps->append(_s_old->bci() + ofs_old);
362 _fwd_jmps->append(_s_new->bci() + ofs_new);
363 }
364 } else if (c_old == Bytecodes::_tableswitch) {
365 int lo_old = (int) Bytes::get_Java_u4(aligned_bcp_old + jintSize);
366 int lo_new = (int) Bytes::get_Java_u4(aligned_bcp_new + jintSize);
367 if (lo_old != lo_new)
368 return false;
369 int hi_old = (int) Bytes::get_Java_u4(aligned_bcp_old + 2*jintSize);
370 int hi_new = (int) Bytes::get_Java_u4(aligned_bcp_new + 2*jintSize);
371 if (hi_old != hi_new)
372 return false;
373 for (int i = 0; i < hi_old - lo_old + 1; i++) {
374 int ofs_old = (int) Bytes::get_Java_u4(aligned_bcp_old + (3+i)*jintSize);
375 int ofs_new = (int) Bytes::get_Java_u4(aligned_bcp_new + (3+i)*jintSize);
376 _fwd_jmps->append(_s_old->bci() + ofs_old);
377 _fwd_jmps->append(_s_new->bci() + ofs_new);
378 }
379 }
380 } else { // !_switchable_test, can use fast rough compare
381 int len_old = _s_old->instruction_size();
382 int len_new = _s_new->instruction_size();
383 if (len_old != len_new)
384 return false;
385 if (memcmp(_s_old->bcp(), _s_new->bcp(), len_old) != 0)
386 return false;
387 }
388 break;
389 }
390 }
391
392 return true;
393 }
394
395
396 int MethodComparator::check_stack_and_locals_size(methodOop old_method, methodOop new_method) {
397 if (old_method->max_stack() != new_method->max_stack()) {
398 return 1;
399 } else if (old_method->max_locals() != new_method->max_locals()) {
400 return 2;
401 } else if (old_method->size_of_parameters() != new_method->size_of_parameters()) {
402 return 3;
403 } else return 0;
404 }