1 /*
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3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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13  * accompanied this code).
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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 
35 BytecodeStream *MethodComparator::_s_old;
36 BytecodeStream *MethodComparator::_s_new;
37 ConstantPool* MethodComparator::_old_cp;
38 ConstantPool* MethodComparator::_new_cp;
39 
methods_EMCP(Method * old_method,Method * new_method)40 bool 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   Thread* THREAD = Thread::current();
56   BytecodeStream s_old(methodHandle(THREAD, old_method));
57   BytecodeStream s_new(methodHandle(THREAD, new_method));
58   _s_old = &s_old;
59   _s_new = &s_new;
60   Bytecodes::Code c_old, c_new;
61 
62   while ((c_old = s_old.next()) >= 0) {
63     if ((c_new = s_new.next()) < 0 || c_old != c_new)
64       return false;
65 
66     if (! args_same(c_old, c_new))
67       return false;
68   }
69   return true;
70 }
71 
args_same(Bytecodes::Code c_old,Bytecodes::Code c_new)72 bool MethodComparator::args_same(Bytecodes::Code c_old, Bytecodes::Code c_new) {
73   // BytecodeStream returns the correct standard Java bytecodes for various "fast"
74   // bytecode versions, so we don't have to bother about them here..
75   switch (c_old) {
76   case Bytecodes::_new            : // fall through
77   case Bytecodes::_anewarray      : // fall through
78   case Bytecodes::_multianewarray : // fall through
79   case Bytecodes::_checkcast      : // fall through
80   case Bytecodes::_instanceof     : {
81     u2 cpi_old = _s_old->get_index_u2();
82     u2 cpi_new = _s_new->get_index_u2();
83     if ((_old_cp->klass_at_noresolve(cpi_old) != _new_cp->klass_at_noresolve(cpi_new)))
84         return false;
85     if (c_old == Bytecodes::_multianewarray &&
86         *(jbyte*)(_s_old->bcp() + 3) != *(jbyte*)(_s_new->bcp() + 3))
87       return false;
88     break;
89   }
90 
91   case Bytecodes::_getstatic       : // fall through
92   case Bytecodes::_putstatic       : // fall through
93   case Bytecodes::_getfield        : // fall through
94   case Bytecodes::_putfield        : // fall through
95   case Bytecodes::_invokevirtual   : // fall through
96   case Bytecodes::_invokespecial   : // fall through
97   case Bytecodes::_invokestatic    : // fall through
98   case Bytecodes::_invokeinterface : {
99     int cpci_old = _s_old->get_index_u2_cpcache();
100     int cpci_new = _s_new->get_index_u2_cpcache();
101     // Check if the names of classes, field/method names and signatures at these indexes
102     // are the same. Indices which are really into constantpool cache (rather than constant
103     // pool itself) are accepted by the constantpool query routines below.
104     if ((_old_cp->klass_ref_at_noresolve(cpci_old) != _new_cp->klass_ref_at_noresolve(cpci_new)) ||
105         (_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
106         (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
107       return false;
108     break;
109   }
110   case Bytecodes::_invokedynamic: {
111     int cpci_old = _s_old->get_index_u4();
112     int cpci_new = _s_new->get_index_u4();
113 
114     // Check if the names of classes, field/method names and signatures at these indexes
115     // are the same. Indices which are really into constantpool cache (rather than constant
116     // pool itself) are accepted by the constantpool query routines below.
117     if ((_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
118         (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
119       return false;
120 
121     // Translate object indexes to constant pool cache indexes.
122     cpci_old = _old_cp->invokedynamic_cp_cache_index(cpci_old);
123     cpci_new = _new_cp->invokedynamic_cp_cache_index(cpci_new);
124 
125     int cpi_old = _old_cp->cache()->entry_at(cpci_old)->constant_pool_index();
126     int cpi_new = _new_cp->cache()->entry_at(cpci_new)->constant_pool_index();
127     int bsm_old = _old_cp->bootstrap_method_ref_index_at(cpi_old);
128     int bsm_new = _new_cp->bootstrap_method_ref_index_at(cpi_new);
129     if (!pool_constants_same(bsm_old, bsm_new))
130       return false;
131     int cnt_old = _old_cp->bootstrap_argument_count_at(cpi_old);
132     int cnt_new = _new_cp->bootstrap_argument_count_at(cpi_new);
133     if (cnt_old != cnt_new)
134       return false;
135     for (int arg_i = 0; arg_i < cnt_old; arg_i++) {
136       int idx_old = _old_cp->bootstrap_argument_index_at(cpi_old, arg_i);
137       int idx_new = _new_cp->bootstrap_argument_index_at(cpi_new, arg_i);
138       if (!pool_constants_same(idx_old, idx_new))
139         return false;
140     }
141     break;
142   }
143 
144   case Bytecodes::_ldc   : // fall through
145   case Bytecodes::_ldc_w : {
146     Bytecode_loadconstant ldc_old(_s_old->method(), _s_old->bci());
147     Bytecode_loadconstant ldc_new(_s_new->method(), _s_new->bci());
148     int cpi_old = ldc_old.pool_index();
149     int cpi_new = ldc_new.pool_index();
150     if (!pool_constants_same(cpi_old, cpi_new))
151       return false;
152     break;
153   }
154 
155   case Bytecodes::_ldc2_w : {
156     u2 cpi_old = _s_old->get_index_u2();
157     u2 cpi_new = _s_new->get_index_u2();
158     constantTag tag_old = _old_cp->tag_at(cpi_old);
159     constantTag tag_new = _new_cp->tag_at(cpi_new);
160     if (tag_old.value() != tag_new.value())
161       return false;
162     if (tag_old.is_long()) {
163       if (_old_cp->long_at(cpi_old) != _new_cp->long_at(cpi_new))
164         return false;
165     } else {
166       // Use jlong_cast to compare the bits rather than numerical values.
167       // This makes a difference for NaN constants.
168       if (jlong_cast(_old_cp->double_at(cpi_old)) != jlong_cast(_new_cp->double_at(cpi_new)))
169         return false;
170     }
171     break;
172   }
173 
174   case Bytecodes::_bipush :
175     if (_s_old->bcp()[1] != _s_new->bcp()[1])
176       return false;
177     break;
178 
179   case Bytecodes::_sipush    :
180     if (_s_old->get_index_u2() != _s_new->get_index_u2())
181       return false;
182     break;
183 
184   case Bytecodes::_aload  : // fall through
185   case Bytecodes::_astore : // fall through
186   case Bytecodes::_dload  : // fall through
187   case Bytecodes::_dstore : // fall through
188   case Bytecodes::_fload  : // fall through
189   case Bytecodes::_fstore : // fall through
190   case Bytecodes::_iload  : // fall through
191   case Bytecodes::_istore : // fall through
192   case Bytecodes::_lload  : // fall through
193   case Bytecodes::_lstore : // fall through
194   case Bytecodes::_ret    :
195     if (_s_old->is_wide() != _s_new->is_wide())
196       return false;
197     if (_s_old->get_index() != _s_new->get_index())
198       return false;
199     break;
200 
201   case Bytecodes::_goto      : // fall through
202   case Bytecodes::_if_acmpeq : // fall through
203   case Bytecodes::_if_acmpne : // fall through
204   case Bytecodes::_if_icmpeq : // fall through
205   case Bytecodes::_if_icmpne : // fall through
206   case Bytecodes::_if_icmplt : // fall through
207   case Bytecodes::_if_icmpge : // fall through
208   case Bytecodes::_if_icmpgt : // fall through
209   case Bytecodes::_if_icmple : // fall through
210   case Bytecodes::_ifeq      : // fall through
211   case Bytecodes::_ifne      : // fall through
212   case Bytecodes::_iflt      : // fall through
213   case Bytecodes::_ifge      : // fall through
214   case Bytecodes::_ifgt      : // fall through
215   case Bytecodes::_ifle      : // fall through
216   case Bytecodes::_ifnonnull : // fall through
217   case Bytecodes::_ifnull    : // fall through
218   case Bytecodes::_jsr       : {
219     int old_ofs = _s_old->bytecode().get_offset_s2(c_old);
220     int new_ofs = _s_new->bytecode().get_offset_s2(c_new);
221     if (old_ofs != new_ofs)
222       return false;
223     break;
224   }
225 
226   case Bytecodes::_iinc :
227     if (_s_old->is_wide() != _s_new->is_wide())
228       return false;
229     if (! _s_old->is_wide()) {
230       // We could use get_index_u1 and get_constant_u1, but it's simpler to grab both bytes at once:
231       if (Bytes::get_Java_u2(_s_old->bcp() + 1) != Bytes::get_Java_u2(_s_new->bcp() + 1))
232         return false;
233     } else {
234       // We could use get_index_u2 and get_constant_u2, but it's simpler to grab all four bytes at once:
235       if (Bytes::get_Java_u4(_s_old->bcp() + 1) != Bytes::get_Java_u4(_s_new->bcp() + 1))
236         return false;
237     }
238     break;
239 
240   case Bytecodes::_goto_w : // fall through
241   case Bytecodes::_jsr_w  : {
242     int old_ofs = _s_old->bytecode().get_offset_s4(c_old);
243     int new_ofs = _s_new->bytecode().get_offset_s4(c_new);
244     if (old_ofs != new_ofs)
245       return false;
246     break;
247   }
248 
249   case Bytecodes::_lookupswitch : // fall through
250   case Bytecodes::_tableswitch  : {
251     int len_old = _s_old->instruction_size();
252     int len_new = _s_new->instruction_size();
253     if (len_old != len_new)
254       return false;
255     if (memcmp(_s_old->bcp(), _s_new->bcp(), len_old) != 0)
256       return false;
257     break;
258   }
259 
260   default:
261     break;
262   }
263 
264   return true;
265 }
266 
pool_constants_same(int cpi_old,int cpi_new)267 bool MethodComparator::pool_constants_same(int cpi_old, int cpi_new) {
268   constantTag tag_old = _old_cp->tag_at(cpi_old);
269   constantTag tag_new = _new_cp->tag_at(cpi_new);
270   if (tag_old.is_int() || tag_old.is_float()) {
271     if (tag_old.value() != tag_new.value())
272       return false;
273     if (tag_old.is_int()) {
274       if (_old_cp->int_at(cpi_old) != _new_cp->int_at(cpi_new))
275         return false;
276     } else {
277       // Use jint_cast to compare the bits rather than numerical values.
278       // This makes a difference for NaN constants.
279       if (jint_cast(_old_cp->float_at(cpi_old)) != jint_cast(_new_cp->float_at(cpi_new)))
280         return false;
281     }
282   } else if (tag_old.is_string() && tag_new.is_string()) {
283     if (strcmp(_old_cp->string_at_noresolve(cpi_old),
284                _new_cp->string_at_noresolve(cpi_new)) != 0)
285       return false;
286     if (_old_cp->is_pseudo_string_at(cpi_old) || _new_cp->is_pseudo_string_at(cpi_new))
287       return (_old_cp->is_pseudo_string_at(cpi_old) == _new_cp->is_pseudo_string_at(cpi_new));
288   } else if (tag_old.is_klass() || tag_old.is_unresolved_klass()) {
289     // tag_old should be klass - 4881222
290     if (! (tag_new.is_unresolved_klass() || tag_new.is_klass()))
291       return false;
292     if (_old_cp->klass_at_noresolve(cpi_old) !=
293         _new_cp->klass_at_noresolve(cpi_new))
294       return false;
295   } else if (tag_old.is_method_type() && tag_new.is_method_type()) {
296     int mti_old = _old_cp->method_type_index_at(cpi_old);
297     int mti_new = _new_cp->method_type_index_at(cpi_new);
298     if ((_old_cp->symbol_at(mti_old) != _new_cp->symbol_at(mti_new)))
299       return false;
300   } else if (tag_old.is_method_handle() && tag_new.is_method_handle()) {
301     if (_old_cp->method_handle_ref_kind_at(cpi_old) !=
302         _new_cp->method_handle_ref_kind_at(cpi_new))
303       return false;
304     int mhi_old = _old_cp->method_handle_index_at(cpi_old);
305     int mhi_new = _new_cp->method_handle_index_at(cpi_new);
306     if ((_old_cp->uncached_klass_ref_at_noresolve(mhi_old) != _new_cp->uncached_klass_ref_at_noresolve(mhi_new)) ||
307         (_old_cp->uncached_name_ref_at(mhi_old) != _new_cp->uncached_name_ref_at(mhi_new)) ||
308         (_old_cp->uncached_signature_ref_at(mhi_old) != _new_cp->uncached_signature_ref_at(mhi_new)))
309       return false;
310   } else {
311     return false;  // unknown tag
312   }
313   return true;
314 }
315 
316 
check_stack_and_locals_size(Method * old_method,Method * new_method)317 int MethodComparator::check_stack_and_locals_size(Method* old_method, Method* new_method) {
318   if (old_method->max_stack() != new_method->max_stack()) {
319     return 1;
320   } else if (old_method->max_locals() != new_method->max_locals()) {
321     return 2;
322   } else if (old_method->size_of_parameters() != new_method->size_of_parameters()) {
323     return 3;
324   } else return 0;
325 }
326