1 /*
   2  * Copyright (c) 2000, 2012, 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/jvmtiRedefineClassesTrace.hpp"
  29 #include "prims/methodComparator.hpp"
  30 #include "runtime/handles.inline.hpp"
  31 #include "utilities/globalDefinitions.hpp"
  32 
  33 BytecodeStream *MethodComparator::_s_old;
  34 BytecodeStream *MethodComparator::_s_new;
  35 ConstantPool* MethodComparator::_old_cp;
  36 ConstantPool* MethodComparator::_new_cp;
  37 BciMap *MethodComparator::_bci_map;
  38 bool MethodComparator::_switchable_test;
  39 GrowableArray<int> *MethodComparator::_fwd_jmps;
  40 
  41 bool MethodComparator::methods_EMCP(Method* old_method, Method* new_method) {
  42   if (old_method->code_size() != new_method->code_size())
  43     return false;
  44   if (check_stack_and_locals_size(old_method, new_method) != 0) {
  45     // RC_TRACE macro has an embedded ResourceMark
  46     RC_TRACE(0x00800000, ("Methods %s non-comparable with diagnosis %d",
  47       old_method->name()->as_C_string(),
  48       check_stack_and_locals_size(old_method, new_method)));
  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   _switchable_test = false;
  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 
  71 
  72 bool MethodComparator::methods_switchable(Method* old_method, Method* new_method,
  73                                           BciMap &bci_map) {
  74   if (old_method->code_size() > new_method->code_size())
  75     // Something has definitely been deleted in the new method, compared to the old one.
  76     return false;
  77 
  78   if (! check_stack_and_locals_size(old_method, new_method))
  79     return false;
  80 
  81   _old_cp = old_method->constants();
  82   _new_cp = new_method->constants();
  83   BytecodeStream s_old(old_method);
  84   BytecodeStream s_new(new_method);
  85   _s_old = &s_old;
  86   _s_new = &s_new;
  87   _bci_map = &bci_map;
  88   _switchable_test = true;
  89   GrowableArray<int> fwd_jmps(16);
  90   _fwd_jmps = &fwd_jmps;
  91   Bytecodes::Code c_old, c_new;
  92 
  93   while ((c_old = s_old.next()) >= 0) {
  94     if ((c_new = s_new.next()) < 0)
  95       return false;
  96     if (! (c_old == c_new && args_same(c_old, c_new))) {
  97       int old_bci = s_old.bci();
  98       int new_st_bci = s_new.bci();
  99       bool found_match = false;
 100       do {
 101         c_new = s_new.next();
 102         if (c_new == c_old && args_same(c_old, c_new)) {
 103           found_match = true;
 104           break;
 105         }
 106       } while (c_new >= 0);
 107       if (! found_match)
 108         return false;
 109       int new_end_bci = s_new.bci();
 110       bci_map.store_fragment_location(old_bci, new_st_bci, new_end_bci);
 111     }
 112   }
 113 
 114   // Now we can test all forward jumps
 115   for (int i = 0; i < fwd_jmps.length() / 2; i++) {
 116     if (! bci_map.old_and_new_locations_same(fwd_jmps.at(i*2), fwd_jmps.at(i*2+1))) {
 117       RC_TRACE(0x00800000,
 118         ("Fwd jump miss: old dest = %d, calc new dest = %d, act new dest = %d",
 119         fwd_jmps.at(i*2), bci_map.new_bci_for_old(fwd_jmps.at(i*2)),
 120         fwd_jmps.at(i*2+1)));
 121       return false;
 122     }
 123   }
 124 
 125   return true;
 126 }
 127 
 128 
 129 bool MethodComparator::args_same(Bytecodes::Code c_old, Bytecodes::Code c_new) {
 130   // BytecodeStream returns the correct standard Java bytecodes for various "fast"
 131   // bytecode versions, so we don't have to bother about them here..
 132   switch (c_old) {
 133   case Bytecodes::_new            : // fall through
 134   case Bytecodes::_anewarray      : // fall through
 135   case Bytecodes::_multianewarray : // fall through
 136   case Bytecodes::_checkcast      : // fall through
 137   case Bytecodes::_instanceof     : {
 138     u2 cpi_old = _s_old->get_index_u2();
 139     u2 cpi_new = _s_new->get_index_u2();
 140     if ((_old_cp->klass_at_noresolve(cpi_old) != _new_cp->klass_at_noresolve(cpi_new)))
 141         return false;
 142     if (c_old == Bytecodes::_multianewarray &&
 143         *(jbyte*)(_s_old->bcp() + 3) != *(jbyte*)(_s_new->bcp() + 3))
 144       return false;
 145     break;
 146   }
 147 
 148   case Bytecodes::_getstatic       : // fall through
 149   case Bytecodes::_putstatic       : // fall through
 150   case Bytecodes::_getfield        : // fall through
 151   case Bytecodes::_putfield        : // fall through
 152   case Bytecodes::_invokevirtual   : // fall through
 153   case Bytecodes::_invokespecial   : // fall through
 154   case Bytecodes::_invokestatic    : // fall through
 155   case Bytecodes::_invokeinterface : {
 156     int cpci_old = _s_old->get_index_u2_cpcache();
 157     int cpci_new = _s_new->get_index_u2_cpcache();
 158     // Check if the names of classes, field/method names and signatures at these indexes
 159     // are the same. Indices which are really into constantpool cache (rather than constant
 160     // pool itself) are accepted by the constantpool query routines below.
 161     if ((_old_cp->klass_ref_at_noresolve(cpci_old) != _new_cp->klass_ref_at_noresolve(cpci_new)) ||
 162         (_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
 163         (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
 164       return false;
 165     break;
 166   }
 167   case Bytecodes::_invokedynamic: {
 168     int cpci_old = _s_old->get_index_u4();
 169     int cpci_new = _s_new->get_index_u4();
 170 
 171     // Check if the names of classes, field/method names and signatures at these indexes
 172     // are the same. Indices which are really into constantpool cache (rather than constant
 173     // pool itself) are accepted by the constantpool query routines below.
 174     if ((_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||
 175         (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))
 176       return false;
 177 
 178     // Translate object indexes to constant pool cache indexes.
 179     cpci_old = _old_cp->invokedynamic_cp_cache_index(cpci_old);
 180     cpci_new = _new_cp->invokedynamic_cp_cache_index(cpci_new);
 181 
 182     int cpi_old = _old_cp->cache()->entry_at(cpci_old)->constant_pool_index();
 183     int cpi_new = _new_cp->cache()->entry_at(cpci_new)->constant_pool_index();
 184     int bsm_old = _old_cp->invoke_dynamic_bootstrap_method_ref_index_at(cpi_old);
 185     int bsm_new = _new_cp->invoke_dynamic_bootstrap_method_ref_index_at(cpi_new);
 186     if (!pool_constants_same(bsm_old, bsm_new))
 187       return false;
 188     int cnt_old = _old_cp->invoke_dynamic_argument_count_at(cpi_old);
 189     int cnt_new = _new_cp->invoke_dynamic_argument_count_at(cpi_new);
 190     if (cnt_old != cnt_new)
 191       return false;
 192     for (int arg_i = 0; arg_i < cnt_old; arg_i++) {
 193       int idx_old = _old_cp->invoke_dynamic_argument_index_at(cpi_old, arg_i);
 194       int idx_new = _new_cp->invoke_dynamic_argument_index_at(cpi_new, arg_i);
 195       if (!pool_constants_same(idx_old, idx_new))
 196         return false;
 197     }
 198     break;
 199   }
 200 
 201   case Bytecodes::_ldc   : // fall through
 202   case Bytecodes::_ldc_w : {
 203     Bytecode_loadconstant ldc_old(_s_old->method(), _s_old->bci());
 204     Bytecode_loadconstant ldc_new(_s_new->method(), _s_new->bci());
 205     int cpi_old = ldc_old.pool_index();
 206     int cpi_new = ldc_new.pool_index();
 207     if (!pool_constants_same(cpi_old, cpi_new))
 208       return false;
 209     break;
 210   }
 211 
 212   case Bytecodes::_ldc2_w : {
 213     u2 cpi_old = _s_old->get_index_u2();
 214     u2 cpi_new = _s_new->get_index_u2();
 215     constantTag tag_old = _old_cp->tag_at(cpi_old);
 216     constantTag tag_new = _new_cp->tag_at(cpi_new);
 217     if (tag_old.value() != tag_new.value())
 218       return false;
 219     if (tag_old.is_long()) {
 220       if (_old_cp->long_at(cpi_old) != _new_cp->long_at(cpi_new))
 221         return false;
 222     } else {
 223       // Use jlong_cast to compare the bits rather than numerical values.
 224       // This makes a difference for NaN constants.
 225       if (jlong_cast(_old_cp->double_at(cpi_old)) != jlong_cast(_new_cp->double_at(cpi_new)))
 226         return false;
 227     }
 228     break;
 229   }
 230 
 231   case Bytecodes::_bipush :
 232     if (_s_old->bcp()[1] != _s_new->bcp()[1])
 233       return false;
 234     break;
 235 
 236   case Bytecodes::_sipush    :
 237     if (_s_old->get_index_u2() != _s_new->get_index_u2())
 238       return false;
 239     break;
 240 
 241   case Bytecodes::_aload  : // fall through
 242   case Bytecodes::_astore : // fall through
 243   case Bytecodes::_dload  : // fall through
 244   case Bytecodes::_dstore : // fall through
 245   case Bytecodes::_fload  : // fall through
 246   case Bytecodes::_fstore : // fall through
 247   case Bytecodes::_iload  : // fall through
 248   case Bytecodes::_istore : // fall through
 249   case Bytecodes::_lload  : // fall through
 250   case Bytecodes::_lstore : // fall through
 251   case Bytecodes::_ret    :
 252     if (_s_old->is_wide() != _s_new->is_wide())
 253       return false;
 254     if (_s_old->get_index() != _s_new->get_index())
 255       return false;
 256     break;
 257 
 258   case Bytecodes::_goto      : // fall through
 259   case Bytecodes::_if_acmpeq : // fall through
 260   case Bytecodes::_if_acmpne : // fall through
 261   case Bytecodes::_if_icmpeq : // fall through
 262   case Bytecodes::_if_icmpne : // fall through
 263   case Bytecodes::_if_icmplt : // fall through
 264   case Bytecodes::_if_icmpge : // fall through
 265   case Bytecodes::_if_icmpgt : // fall through
 266   case Bytecodes::_if_icmple : // fall through
 267   case Bytecodes::_ifeq      : // fall through
 268   case Bytecodes::_ifne      : // fall through
 269   case Bytecodes::_iflt      : // fall through
 270   case Bytecodes::_ifge      : // fall through
 271   case Bytecodes::_ifgt      : // fall through
 272   case Bytecodes::_ifle      : // fall through
 273   case Bytecodes::_ifnonnull : // fall through
 274   case Bytecodes::_ifnull    : // fall through
 275   case Bytecodes::_jsr       : {
 276     int old_ofs = _s_old->bytecode().get_offset_s2(c_old);
 277     int new_ofs = _s_new->bytecode().get_offset_s2(c_new);
 278     if (_switchable_test) {
 279       int old_dest = _s_old->bci() + old_ofs;
 280       int new_dest = _s_new->bci() + new_ofs;
 281       if (old_ofs < 0 && new_ofs < 0) {
 282         if (! _bci_map->old_and_new_locations_same(old_dest, new_dest))
 283           return false;
 284       } else if (old_ofs > 0 && new_ofs > 0) {
 285         _fwd_jmps->append(old_dest);
 286         _fwd_jmps->append(new_dest);
 287       } else {
 288         return false;
 289       }
 290     } else {
 291       if (old_ofs != new_ofs)
 292         return false;
 293     }
 294     break;
 295   }
 296 
 297   case Bytecodes::_iinc :
 298     if (_s_old->is_wide() != _s_new->is_wide())
 299       return false;
 300     if (! _s_old->is_wide()) {
 301       // We could use get_index_u1 and get_constant_u1, but it's simpler to grab both bytes at once:
 302       if (Bytes::get_Java_u2(_s_old->bcp() + 1) != Bytes::get_Java_u2(_s_new->bcp() + 1))
 303         return false;
 304     } else {
 305       // We could use get_index_u2 and get_constant_u2, but it's simpler to grab all four bytes at once:
 306       if (Bytes::get_Java_u4(_s_old->bcp() + 1) != Bytes::get_Java_u4(_s_new->bcp() + 1))
 307         return false;
 308     }
 309     break;
 310 
 311   case Bytecodes::_goto_w : // fall through
 312   case Bytecodes::_jsr_w  : {
 313     int old_ofs = _s_old->bytecode().get_offset_s4(c_old);
 314     int new_ofs = _s_new->bytecode().get_offset_s4(c_new);
 315     if (_switchable_test) {
 316       int old_dest = _s_old->bci() + old_ofs;
 317       int new_dest = _s_new->bci() + new_ofs;
 318       if (old_ofs < 0 && new_ofs < 0) {
 319         if (! _bci_map->old_and_new_locations_same(old_dest, new_dest))
 320           return false;
 321       } else if (old_ofs > 0 && new_ofs > 0) {
 322         _fwd_jmps->append(old_dest);
 323         _fwd_jmps->append(new_dest);
 324       } else {
 325         return false;
 326       }
 327     } else {
 328       if (old_ofs != new_ofs)
 329         return false;
 330     }
 331     break;
 332   }
 333 
 334   case Bytecodes::_lookupswitch : // fall through
 335   case Bytecodes::_tableswitch  : {
 336     if (_switchable_test) {
 337       address aligned_bcp_old = (address) round_to((intptr_t)_s_old->bcp() + 1, jintSize);
 338       address aligned_bcp_new = (address) round_to((intptr_t)_s_new->bcp() + 1, jintSize);
 339       int default_old = (int) Bytes::get_Java_u4(aligned_bcp_old);
 340       int default_new = (int) Bytes::get_Java_u4(aligned_bcp_new);
 341       _fwd_jmps->append(_s_old->bci() + default_old);
 342       _fwd_jmps->append(_s_new->bci() + default_new);
 343       if (c_old == Bytecodes::_lookupswitch) {
 344         int npairs_old = (int) Bytes::get_Java_u4(aligned_bcp_old + jintSize);
 345         int npairs_new = (int) Bytes::get_Java_u4(aligned_bcp_new + jintSize);
 346         if (npairs_old != npairs_new)
 347           return false;
 348         for (int i = 0; i < npairs_old; i++) {
 349           int match_old = (int) Bytes::get_Java_u4(aligned_bcp_old + (2+2*i)*jintSize);
 350           int match_new = (int) Bytes::get_Java_u4(aligned_bcp_new + (2+2*i)*jintSize);
 351           if (match_old != match_new)
 352             return false;
 353           int ofs_old = (int) Bytes::get_Java_u4(aligned_bcp_old + (2+2*i+1)*jintSize);
 354           int ofs_new = (int) Bytes::get_Java_u4(aligned_bcp_new + (2+2*i+1)*jintSize);
 355           _fwd_jmps->append(_s_old->bci() + ofs_old);
 356           _fwd_jmps->append(_s_new->bci() + ofs_new);
 357         }
 358       } else if (c_old == Bytecodes::_tableswitch) {
 359         int lo_old = (int) Bytes::get_Java_u4(aligned_bcp_old + jintSize);
 360         int lo_new = (int) Bytes::get_Java_u4(aligned_bcp_new + jintSize);
 361         if (lo_old != lo_new)
 362           return false;
 363         int hi_old = (int) Bytes::get_Java_u4(aligned_bcp_old + 2*jintSize);
 364         int hi_new = (int) Bytes::get_Java_u4(aligned_bcp_new + 2*jintSize);
 365         if (hi_old != hi_new)
 366           return false;
 367         for (int i = 0; i < hi_old - lo_old + 1; i++) {
 368           int ofs_old = (int) Bytes::get_Java_u4(aligned_bcp_old + (3+i)*jintSize);
 369           int ofs_new = (int) Bytes::get_Java_u4(aligned_bcp_new + (3+i)*jintSize);
 370           _fwd_jmps->append(_s_old->bci() + ofs_old);
 371           _fwd_jmps->append(_s_new->bci() + ofs_new);
 372         }
 373       }
 374     } else { // !_switchable_test, can use fast rough compare
 375       int len_old = _s_old->instruction_size();
 376       int len_new = _s_new->instruction_size();
 377       if (len_old != len_new)
 378         return false;
 379       if (memcmp(_s_old->bcp(), _s_new->bcp(), len_old) != 0)
 380         return false;
 381     }
 382     break;
 383   }
 384   }
 385 
 386   return true;
 387 }
 388 
 389 bool MethodComparator::pool_constants_same(int cpi_old, int cpi_new) {
 390   constantTag tag_old = _old_cp->tag_at(cpi_old);
 391   constantTag tag_new = _new_cp->tag_at(cpi_new);
 392   if (tag_old.is_int() || tag_old.is_float()) {
 393     if (tag_old.value() != tag_new.value())
 394       return false;
 395     if (tag_old.is_int()) {
 396       if (_old_cp->int_at(cpi_old) != _new_cp->int_at(cpi_new))
 397         return false;
 398     } else {
 399       // Use jint_cast to compare the bits rather than numerical values.
 400       // This makes a difference for NaN constants.
 401       if (jint_cast(_old_cp->float_at(cpi_old)) != jint_cast(_new_cp->float_at(cpi_new)))
 402         return false;
 403     }
 404   } else if (tag_old.is_string() && tag_new.is_string()) {
 405     if (strcmp(_old_cp->string_at_noresolve(cpi_old),
 406                _new_cp->string_at_noresolve(cpi_new)) != 0)
 407       return false;
 408   } else if (tag_old.is_klass() || tag_old.is_unresolved_klass()) {
 409     // tag_old should be klass - 4881222
 410     if (! (tag_new.is_unresolved_klass() || tag_new.is_klass()))
 411       return false;
 412     if (_old_cp->klass_at_noresolve(cpi_old) !=
 413         _new_cp->klass_at_noresolve(cpi_new))
 414       return false;
 415   } else if (tag_old.is_method_type() && tag_new.is_method_type()) {
 416     int mti_old = _old_cp->method_type_index_at(cpi_old);
 417     int mti_new = _new_cp->method_type_index_at(cpi_new);
 418     if ((_old_cp->symbol_at(mti_old) != _new_cp->symbol_at(mti_new)))
 419       return false;
 420   } else if (tag_old.is_method_handle() && tag_new.is_method_handle()) {
 421     if (_old_cp->method_handle_ref_kind_at(cpi_old) !=
 422         _new_cp->method_handle_ref_kind_at(cpi_new))
 423       return false;
 424     int mhi_old = _old_cp->method_handle_index_at(cpi_old);
 425     int mhi_new = _new_cp->method_handle_index_at(cpi_new);
 426     if ((_old_cp->uncached_klass_ref_at_noresolve(mhi_old) != _new_cp->uncached_klass_ref_at_noresolve(mhi_new)) ||
 427         (_old_cp->uncached_name_ref_at(mhi_old) != _new_cp->uncached_name_ref_at(mhi_new)) ||
 428         (_old_cp->uncached_signature_ref_at(mhi_old) != _new_cp->uncached_signature_ref_at(mhi_new)))
 429       return false;
 430   } else {
 431     return false;  // unknown tag
 432   }
 433   return true;
 434 }
 435 
 436 
 437 int MethodComparator::check_stack_and_locals_size(Method* old_method, Method* new_method) {
 438   if (old_method->max_stack() != new_method->max_stack()) {
 439     return 1;
 440   } else if (old_method->max_locals() != new_method->max_locals()) {
 441     return 2;
 442   } else if (old_method->size_of_parameters() != new_method->size_of_parameters()) {
 443     return 3;
 444   } else return 0;
 445 }