1 /*

     2  * Copyright 2000-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any 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_big();

   134     u2 cpi_new = _s_new->get_index_big();

   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::_invokeinterface : {

   151     u2 cpci_old = _s_old->get_index_big();

   152     u2 cpci_new = _s_new->get_index_big();

   153     // Check if the names of classes, field/method names and signatures at these indexes

   154     // are the same. Indices which are really into constantpool cache (rather than constant

   155     // pool itself) are accepted by the constantpool query routines below.

   156     if ((_old_cp->klass_ref_at_noresolve(cpci_old) != _new_cp->klass_ref_at_noresolve(cpci_new)) ||

   157         (_old_cp->name_ref_at(cpci_old) != _new_cp->name_ref_at(cpci_new)) ||

   158         (_old_cp->signature_ref_at(cpci_old) != _new_cp->signature_ref_at(cpci_new)))

   159       return false;

   160     break;

   161   }

   162 

   163   case Bytecodes::_ldc   : // fall through

   164   case Bytecodes::_ldc_w : {

   165     u2 cpi_old, cpi_new;

   166     if (c_old == Bytecodes::_ldc) {

   167       cpi_old = _s_old->bcp()[1];

   168       cpi_new = _s_new->bcp()[1];

   169     } else {

   170       cpi_old = _s_old->get_index_big();

   171       cpi_new = _s_new->get_index_big();

   172     }

   173     constantTag tag_old = _old_cp->tag_at(cpi_old);

   174     constantTag tag_new = _new_cp->tag_at(cpi_new);

   175     if (tag_old.is_int() || tag_old.is_float()) {

   176       if (tag_old.value() != tag_new.value())

   177         return false;

   178       if (tag_old.is_int()) {

   179         if (_old_cp->int_at(cpi_old) != _new_cp->int_at(cpi_new))

   180           return false;

   181       } else {

   182         if (_old_cp->float_at(cpi_old) != _new_cp->float_at(cpi_new))

   183           return false;

   184       }

   185     } else if (tag_old.is_string() || tag_old.is_unresolved_string()) {

   186       if (! (tag_new.is_unresolved_string() || tag_new.is_string()))

   187         return false;

   188       if (strcmp(_old_cp->string_at_noresolve(cpi_old),

   189                  _new_cp->string_at_noresolve(cpi_new)) != 0)

   190         return false;

   191     } else { // 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     }

   198     break;

   199   }

   200 

   201   case Bytecodes::_ldc2_w : {

   202     u2 cpi_old = _s_old->get_index_big();

   203     u2 cpi_new = _s_new->get_index_big();

   204     constantTag tag_old = _old_cp->tag_at(cpi_old);

   205     constantTag tag_new = _new_cp->tag_at(cpi_new);

   206     if (tag_old.value() != tag_new.value())

   207       return false;

   208     if (tag_old.is_long()) {

   209       if (_old_cp->long_at(cpi_old) != _new_cp->long_at(cpi_new))

   210         return false;

   211     } else {

   212       if (_old_cp->double_at(cpi_old) != _new_cp->double_at(cpi_new))

   213         return false;

   214     }

   215     break;

   216   }

   217 

   218   case Bytecodes::_bipush :

   219     if (_s_old->bcp()[1] != _s_new->bcp()[1])

   220       return false;

   221     break;

   222 

   223   case Bytecodes::_sipush    :

   224     if (_s_old->get_index_big() != _s_new->get_index_big())

   225       return false;

   226     break;

   227 

   228   case Bytecodes::_aload  : // fall through

   229   case Bytecodes::_astore : // fall through

   230   case Bytecodes::_dload  : // fall through

   231   case Bytecodes::_dstore : // fall through

   232   case Bytecodes::_fload  : // fall through

   233   case Bytecodes::_fstore : // fall through

   234   case Bytecodes::_iload  : // fall through

   235   case Bytecodes::_istore : // fall through

   236   case Bytecodes::_lload  : // fall through

   237   case Bytecodes::_lstore : // fall through

   238   case Bytecodes::_ret    :

   239     if (_s_old->is_wide() != _s_new->is_wide())

   240       return false;

   241     if (_s_old->get_index() != _s_new->get_index())

   242       return false;

   243     break;

   244 

   245   case Bytecodes::_goto      : // fall through

   246   case Bytecodes::_if_acmpeq : // fall through

   247   case Bytecodes::_if_acmpne : // fall through

   248   case Bytecodes::_if_icmpeq : // fall through

   249   case Bytecodes::_if_icmpne : // fall through

   250   case Bytecodes::_if_icmplt : // fall through

   251   case Bytecodes::_if_icmpge : // fall through

   252   case Bytecodes::_if_icmpgt : // fall through

   253   case Bytecodes::_if_icmple : // fall through

   254   case Bytecodes::_ifeq      : // fall through

   255   case Bytecodes::_ifne      : // fall through

   256   case Bytecodes::_iflt      : // fall through

   257   case Bytecodes::_ifge      : // fall through

   258   case Bytecodes::_ifgt      : // fall through

   259   case Bytecodes::_ifle      : // fall through

   260   case Bytecodes::_ifnonnull : // fall through

   261   case Bytecodes::_ifnull    : // fall through

   262   case Bytecodes::_jsr       : {

   263     short old_ofs = (short) _s_old->get_index_big();

   264     short new_ofs = (short) _s_new->get_index_big();

   265     if (_switchable_test) {

   266       int old_dest = _s_old->bci() + old_ofs;

   267       int new_dest = _s_new->bci() + new_ofs;

   268       if (old_ofs < 0 && new_ofs < 0) {

   269         if (! _bci_map->old_and_new_locations_same(old_dest, new_dest))

   270           return false;

   271       } else if (old_ofs > 0 && new_ofs > 0) {

   272         _fwd_jmps->append(old_dest);

   273         _fwd_jmps->append(new_dest);

   274       } else {

   275         return false;

   276       }

   277     } else {

   278       if (old_ofs != new_ofs)

   279         return false;

   280     }

   281     break;

   282   }

   283 

   284   case Bytecodes::_iinc :

   285     if (_s_old->is_wide() != _s_new->is_wide())

   286       return false;

   287     if (! _s_old->is_wide()) {

   288       if (_s_old->get_index_big() != _s_new->get_index_big())

   289         return false;

   290     } else {

   291       if (Bytes::get_Java_u4(_s_old->bcp() + 1) != Bytes::get_Java_u4(_s_new->bcp() + 1))

   292         return false;

   293     }

   294     break;

   295 

   296   case Bytecodes::_goto_w : // fall through

   297   case Bytecodes::_jsr_w  : {

   298     int old_ofs = (int) Bytes::get_Java_u4(_s_old->bcp() + 1);

   299     int new_ofs = (int) Bytes::get_Java_u4(_s_new->bcp() + 1);

   300     if (_switchable_test) {

   301       int old_dest = _s_old->bci() + old_ofs;

   302       int new_dest = _s_new->bci() + new_ofs;

   303       if (old_ofs < 0 && new_ofs < 0) {

   304         if (! _bci_map->old_and_new_locations_same(old_dest, new_dest))

   305           return false;

   306       } else if (old_ofs > 0 && new_ofs > 0) {

   307         _fwd_jmps->append(old_dest);

   308         _fwd_jmps->append(new_dest);

   309       } else {

   310         return false;

   311       }

   312     } else {

   313       if (old_ofs != new_ofs)

   314         return false;

   315     }

   316     break;

   317   }

   318 

   319   case Bytecodes::_lookupswitch : // fall through

   320   case Bytecodes::_tableswitch  : {

   321     if (_switchable_test) {

   322       address aligned_bcp_old = (address) round_to((intptr_t)_s_old->bcp() + 1, jintSize);

   323       address aligned_bcp_new = (address) round_to((intptr_t)_s_new->bcp() + 1, jintSize);

   324       int default_old = (int) Bytes::get_Java_u4(aligned_bcp_old);

   325       int default_new = (int) Bytes::get_Java_u4(aligned_bcp_new);

   326       _fwd_jmps->append(_s_old->bci() + default_old);

   327       _fwd_jmps->append(_s_new->bci() + default_new);

   328       if (c_old == Bytecodes::_lookupswitch) {

   329         int npairs_old = (int) Bytes::get_Java_u4(aligned_bcp_old + jintSize);

   330         int npairs_new = (int) Bytes::get_Java_u4(aligned_bcp_new + jintSize);

   331         if (npairs_old != npairs_new)

   332           return false;

   333         for (int i = 0; i < npairs_old; i++) {

   334           int match_old = (int) Bytes::get_Java_u4(aligned_bcp_old + (2+2*i)*jintSize);

   335           int match_new = (int) Bytes::get_Java_u4(aligned_bcp_new + (2+2*i)*jintSize);

   336           if (match_old != match_new)

   337             return false;

   338           int ofs_old = (int) Bytes::get_Java_u4(aligned_bcp_old + (2+2*i+1)*jintSize);

   339           int ofs_new = (int) Bytes::get_Java_u4(aligned_bcp_new + (2+2*i+1)*jintSize);

   340           _fwd_jmps->append(_s_old->bci() + ofs_old);

   341           _fwd_jmps->append(_s_new->bci() + ofs_new);

   342         }

   343       } else if (c_old == Bytecodes::_tableswitch) {

   344         int lo_old = (int) Bytes::get_Java_u4(aligned_bcp_old + jintSize);

   345         int lo_new = (int) Bytes::get_Java_u4(aligned_bcp_new + jintSize);

   346         if (lo_old != lo_new)

   347           return false;

   348         int hi_old = (int) Bytes::get_Java_u4(aligned_bcp_old + 2*jintSize);

   349         int hi_new = (int) Bytes::get_Java_u4(aligned_bcp_new + 2*jintSize);

   350         if (hi_old != hi_new)

   351           return false;

   352         for (int i = 0; i < hi_old - lo_old + 1; i++) {

   353           int ofs_old = (int) Bytes::get_Java_u4(aligned_bcp_old + (3+i)*jintSize);

   354           int ofs_new = (int) Bytes::get_Java_u4(aligned_bcp_new + (3+i)*jintSize);

   355           _fwd_jmps->append(_s_old->bci() + ofs_old);

   356           _fwd_jmps->append(_s_new->bci() + ofs_new);

   357         }

   358       }

   359     } else { // !_switchable_test, can use fast rough compare

   360       int len_old = _s_old->next_bcp() - _s_old->bcp();

   361       int len_new = _s_new->next_bcp() - _s_new->bcp();

   362       if (len_old != len_new)

   363         return false;

   364       if (memcmp(_s_old->bcp(), _s_new->bcp(), len_old) != 0)

   365         return false;

   366     }

   367     break;

   368   }

   369   }

   370 

   371   return true;

   372 }

   373 

   374 

   375 int MethodComparator::check_stack_and_locals_size(methodOop old_method, methodOop new_method) {

   376   if (old_method->max_stack() != new_method->max_stack()) {

   377     return 1;

   378   } else if (old_method->max_locals() != new_method->max_locals()) {

   379     return 2;

   380   } else if (old_method->size_of_parameters() != new_method->size_of_parameters()) {

   381     return 3;

   382   } else return 0;

   383 }