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
32BytecodeStream *MethodComparator::_s_old;
33BytecodeStream *MethodComparator::_s_new;
34ConstantPool* MethodComparator::_old_cp;
35ConstantPool* MethodComparator::_new_cp;
36
37bool 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
68bool 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
263bool 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
313int 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}
322