Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright 1997-2009 Sun Microsystems, Inc.  All Rights Reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

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

  * have any questions.

  *

  */

 # include "incls/_precompiled.incl"

 # include "incls/_constantPoolOop.cpp.incl"

 void constantPoolOopDesc::set_flag_at(FlagBit fb) {

   const int MAX_STATE_CHANGES = 2;

   for (int i = MAX_STATE_CHANGES + 10; i > 0; i--) {

     int oflags = _flags;

     int nflags = oflags | (1 << (int)fb);

     if (Atomic::cmpxchg(nflags, &_flags, oflags) == oflags)

       return;

   }

   assert(false, "failed to cmpxchg flags");

   _flags |= (1 << (int)fb);     // better than nothing

 }

 klassOop constantPoolOopDesc::klass_at_impl(constantPoolHandle this_oop, int which, TRAPS) {

   // A resolved constantPool entry will contain a klassOop, otherwise a symbolOop.

   // It is not safe to rely on the tag bit's here, since we don't have a lock, and the entry and

   // tag is not updated atomicly.

   oop entry = *(this_oop->obj_at_addr(which));

   if (entry->is_klass()) {

     // Already resolved - return entry.

     return (klassOop)entry;

   }

   // Acquire lock on constant oop while doing update. After we get the lock, we check if another object

   // already has updated the object

   assert(THREAD->is_Java_thread(), "must be a Java thread");

   bool do_resolve = false;

   bool in_error = false;

   symbolHandle name;

   Handle       loader;

   { ObjectLocker ol(this_oop, THREAD);

     if (this_oop->tag_at(which).is_unresolved_klass()) {

       if (this_oop->tag_at(which).is_unresolved_klass_in_error()) {

         in_error = true;

       } else {

         do_resolve = true;

         name   = symbolHandle(THREAD, this_oop->unresolved_klass_at(which));

         loader = Handle(THREAD, instanceKlass::cast(this_oop->pool_holder())->class_loader());

       }

     }

   } // unlocking constantPool

   // The original attempt to resolve this constant pool entry failed so find the

   // original error and throw it again (JVMS 5.4.3).

   if (in_error) {

     symbolOop error = SystemDictionary::find_resolution_error(this_oop, which);

     guarantee(error != (symbolOop)NULL, "tag mismatch with resolution error table");

     ResourceMark rm;

     // exception text will be the class name

     const char* className = this_oop->unresolved_klass_at(which)->as_C_string();

     THROW_MSG_0(error, className);

   }

   if (do_resolve) {

     // this_oop must be unlocked during resolve_or_fail

     oop protection_domain = Klass::cast(this_oop->pool_holder())->protection_domain();

     Handle h_prot (THREAD, protection_domain);

     klassOop k_oop = SystemDictionary::resolve_or_fail(name, loader, h_prot, true, THREAD);

     KlassHandle k;

     if (!HAS_PENDING_EXCEPTION) {

       k = KlassHandle(THREAD, k_oop);

       // Do access check for klasses

       verify_constant_pool_resolve(this_oop, k, THREAD);

     }

     // Failed to resolve class. We must record the errors so that subsequent attempts

     // to resolve this constant pool entry fail with the same error (JVMS 5.4.3).

     if (HAS_PENDING_EXCEPTION) {

       ResourceMark rm;

       symbolHandle error(PENDING_EXCEPTION->klass()->klass_part()->name());

       bool throw_orig_error = false;

       {

         ObjectLocker ol (this_oop, THREAD);

         // some other thread has beaten us and has resolved the class.

         if (this_oop->tag_at(which).is_klass()) {

           CLEAR_PENDING_EXCEPTION;

           entry = this_oop->resolved_klass_at(which);

           return (klassOop)entry;

         }

         if (!PENDING_EXCEPTION->

               is_a(SystemDictionary::LinkageError_klass())) {

           // Just throw the exception and don't prevent these classes from

           // being loaded due to virtual machine errors like StackOverflow

           // and OutOfMemoryError, etc, or if the thread was hit by stop()

           // Needs clarification to section 5.4.3 of the VM spec (see 6308271)

         }

         else if (!this_oop->tag_at(which).is_unresolved_klass_in_error()) {

           SystemDictionary::add_resolution_error(this_oop, which, error);

           this_oop->tag_at_put(which, JVM_CONSTANT_UnresolvedClassInError);

         } else {

           // some other thread has put the class in error state.

           error = symbolHandle(SystemDictionary::find_resolution_error(this_oop, which));

           assert(!error.is_null(), "checking");

           throw_orig_error = true;

         }

       } // unlocked

       if (throw_orig_error) {

         CLEAR_PENDING_EXCEPTION;

         ResourceMark rm;

         const char* className = this_oop->unresolved_klass_at(which)->as_C_string();

         THROW_MSG_0(error, className);

       }

       return 0;

     }

     if (TraceClassResolution && !k()->klass_part()->oop_is_array()) {

       // skip resolving the constant pool so that this code get's

       // called the next time some bytecodes refer to this class.

       ResourceMark rm;

       int line_number = -1;

       const char * source_file = NULL;

       if (JavaThread::current()->has_last_Java_frame()) {

         // try to identify the method which called this function.

         vframeStream vfst(JavaThread::current());

         if (!vfst.at_end()) {

           line_number = vfst.method()->line_number_from_bci(vfst.bci());

           symbolOop s = instanceKlass::cast(vfst.method()->method_holder())->source_file_name();

           if (s != NULL) {

             source_file = s->as_C_string();

           }

         }

       }

       if (k() != this_oop->pool_holder()) {

         // only print something if the classes are different

         if (source_file != NULL) {

           tty->print("RESOLVE %s %s %s:%d\n",

                      instanceKlass::cast(this_oop->pool_holder())->external_name(),

                      instanceKlass::cast(k())->external_name(), source_file, line_number);

         } else {

           tty->print("RESOLVE %s %s\n",

                      instanceKlass::cast(this_oop->pool_holder())->external_name(),

                      instanceKlass::cast(k())->external_name());

         }

       }

       return k();

     } else {

       ObjectLocker ol (this_oop, THREAD);

       // Only updated constant pool - if it is resolved.

       do_resolve = this_oop->tag_at(which).is_unresolved_klass();

       if (do_resolve) {

         this_oop->klass_at_put(which, k());

       }

     }

   }

   entry = this_oop->resolved_klass_at(which);

   assert(entry->is_klass(), "must be resolved at this point");

   return (klassOop)entry;

 }

 // Does not update constantPoolOop - to avoid any exception throwing. Used

 // by compiler and exception handling.  Also used to avoid classloads for

 // instanceof operations. Returns NULL if the class has not been loaded or

 // if the verification of constant pool failed

 klassOop constantPoolOopDesc::klass_at_if_loaded(constantPoolHandle this_oop, int which) {

   oop entry = *this_oop->obj_at_addr(which);

   if (entry->is_klass()) {

     return (klassOop)entry;

   } else {

     assert(entry->is_symbol(), "must be either symbol or klass");

     Thread *thread = Thread::current();

     symbolHandle name (thread, (symbolOop)entry);

     oop loader = instanceKlass::cast(this_oop->pool_holder())->class_loader();

     oop protection_domain = Klass::cast(this_oop->pool_holder())->protection_domain();

     Handle h_prot (thread, protection_domain);

     Handle h_loader (thread, loader);

     klassOop k = SystemDictionary::find(name, h_loader, h_prot, thread);

     if (k != NULL) {

       // Make sure that resolving is legal

       EXCEPTION_MARK;

       KlassHandle klass(THREAD, k);

       // return NULL if verification fails

       verify_constant_pool_resolve(this_oop, klass, THREAD);

       if (HAS_PENDING_EXCEPTION) {

         CLEAR_PENDING_EXCEPTION;

         return NULL;

       }

       return klass();

     } else {

       return k;

     }

   }

 }

 klassOop constantPoolOopDesc::klass_ref_at_if_loaded(constantPoolHandle this_oop, int which) {

   return klass_at_if_loaded(this_oop, this_oop->klass_ref_index_at(which));

 }

 // This is an interface for the compiler that allows accessing non-resolved entries

 // in the constant pool - but still performs the validations tests. Must be used

 // in a pre-parse of the compiler - to determine what it can do and not do.

 // Note: We cannot update the ConstantPool from the vm_thread.

 klassOop constantPoolOopDesc::klass_ref_at_if_loaded_check(constantPoolHandle this_oop, int index, TRAPS) {

   int which = this_oop->klass_ref_index_at(index);

   oop entry = *this_oop->obj_at_addr(which);

   if (entry->is_klass()) {

     return (klassOop)entry;

   } else {

     assert(entry->is_symbol(), "must be either symbol or klass");

     symbolHandle name (THREAD, (symbolOop)entry);

     oop loader = instanceKlass::cast(this_oop->pool_holder())->class_loader();

     oop protection_domain = Klass::cast(this_oop->pool_holder())->protection_domain();

     Handle h_loader(THREAD, loader);

     Handle h_prot  (THREAD, protection_domain);

     KlassHandle k(THREAD, SystemDictionary::find(name, h_loader, h_prot, THREAD));

     // Do access check for klasses

     if( k.not_null() ) verify_constant_pool_resolve(this_oop, k, CHECK_NULL);

     return k();

   }

 }

 symbolOop constantPoolOopDesc::impl_name_ref_at(int which, bool uncached) {

   int name_index = name_ref_index_at(impl_name_and_type_ref_index_at(which, uncached));

   return symbol_at(name_index);

 }

 symbolOop constantPoolOopDesc::impl_signature_ref_at(int which, bool uncached) {

   int signature_index = signature_ref_index_at(impl_name_and_type_ref_index_at(which, uncached));

   return symbol_at(signature_index);

 }

 int constantPoolOopDesc::impl_name_and_type_ref_index_at(int which, bool uncached) {

   int i = which;

   if (!uncached && cache() != NULL) {

     if (constantPoolCacheOopDesc::is_secondary_index(which))

       // Invokedynamic indexes are always processed in native order

       // so there is no question of reading a native u2 in Java order here.

       return cache()->main_entry_at(which)->constant_pool_index();

     // change byte-ordering and go via cache

     i = remap_instruction_operand_from_cache(which);

   } else {

     if (tag_at(which).is_name_and_type())

       // invokedynamic index is a simple name-and-type

       return which;

   }

   assert(tag_at(i).is_field_or_method(), "Corrupted constant pool");

   jint ref_index = *int_at_addr(i);

   return extract_high_short_from_int(ref_index);

 }

 int constantPoolOopDesc::impl_klass_ref_index_at(int which, bool uncached) {

   guarantee(!constantPoolCacheOopDesc::is_secondary_index(which),

             "an invokedynamic instruction does not have a klass");

   int i = which;

   if (!uncached && cache() != NULL) {

     // change byte-ordering and go via cache

     i = remap_instruction_operand_from_cache(which);

   }

   assert(tag_at(i).is_field_or_method(), "Corrupted constant pool");

   jint ref_index = *int_at_addr(i);

   return extract_low_short_from_int(ref_index);

 }

 int constantPoolOopDesc::remap_instruction_operand_from_cache(int operand) {

   // Operand was fetched by a stream using get_Java_u2, yet was stored

   // by Rewriter::rewrite_member_reference in native order.

   // So now we have to fix the damage by swapping back to native order.

   assert((int)(u2)operand == operand, "clean u2");

   int cpc_index = Bytes::swap_u2(operand);

   int member_index = cache()->entry_at(cpc_index)->constant_pool_index();

   return member_index;

 }

 void constantPoolOopDesc::verify_constant_pool_resolve(constantPoolHandle this_oop, KlassHandle k, TRAPS) {

  if (k->oop_is_instance() || k->oop_is_objArray()) {

     instanceKlassHandle holder (THREAD, this_oop->pool_holder());

     klassOop elem_oop = k->oop_is_instance() ? k() : objArrayKlass::cast(k())->bottom_klass();

     KlassHandle element (THREAD, elem_oop);

     // The element type could be a typeArray - we only need the access check if it is

     // an reference to another class

     if (element->oop_is_instance()) {

       LinkResolver::check_klass_accessability(holder, element, CHECK);

     }

   }

 }

 int constantPoolOopDesc::name_ref_index_at(int which_nt) {

   jint ref_index = name_and_type_at(which_nt);

   return extract_low_short_from_int(ref_index);

 }

 int constantPoolOopDesc::signature_ref_index_at(int which_nt) {

   jint ref_index = name_and_type_at(which_nt);

   return extract_high_short_from_int(ref_index);

 }

 klassOop constantPoolOopDesc::klass_ref_at(int which, TRAPS) {

   return klass_at(klass_ref_index_at(which), CHECK_NULL);

 }

 symbolOop constantPoolOopDesc::klass_name_at(int which) {

   assert(tag_at(which).is_unresolved_klass() || tag_at(which).is_klass(),

          "Corrupted constant pool");

   // A resolved constantPool entry will contain a klassOop, otherwise a symbolOop.

   // It is not safe to rely on the tag bit's here, since we don't have a lock, and the entry and

   // tag is not updated atomicly.

   oop entry = *(obj_at_addr(which));

   if (entry->is_klass()) {

     // Already resolved - return entry's name.

     return klassOop(entry)->klass_part()->name();

   } else {

     assert(entry->is_symbol(), "must be either symbol or klass");

     return (symbolOop)entry;

   }

 }

 symbolOop constantPoolOopDesc::klass_ref_at_noresolve(int which) {

   jint ref_index = klass_ref_index_at(which);

   return klass_at_noresolve(ref_index);

 }

 char* constantPoolOopDesc::string_at_noresolve(int which) {

   // Test entry type in case string is resolved while in here.

   oop entry = *(obj_at_addr(which));

   if (entry->is_symbol()) {

     return ((symbolOop)entry)->as_C_string();

   } else if (java_lang_String::is_instance(entry)) {

     return java_lang_String::as_utf8_string(entry);

   } else {

     return (char*)"<pseudo-string>";

   }

 }

 BasicType constantPoolOopDesc::basic_type_for_signature_at(int which) {

   return FieldType::basic_type(symbol_at(which));

 }

 void constantPoolOopDesc::resolve_string_constants_impl(constantPoolHandle this_oop, TRAPS) {

   for (int index = 1; index < this_oop->length(); index++) { // Index 0 is unused

     if (this_oop->tag_at(index).is_unresolved_string()) {

       this_oop->string_at(index, CHECK);

     }

   }

 }

 oop constantPoolOopDesc::string_at_impl(constantPoolHandle this_oop, int which, TRAPS) {

   oop entry = *(this_oop->obj_at_addr(which));

   if (entry->is_symbol()) {

     ObjectLocker ol(this_oop, THREAD);

     if (this_oop->tag_at(which).is_unresolved_string()) {

       // Intern string

       symbolOop sym = this_oop->unresolved_string_at(which);

       entry = StringTable::intern(sym, CHECK_(constantPoolOop(NULL)));

       this_oop->string_at_put(which, entry);

     } else {

       // Another thread beat us and interned string, read string from constant pool

       entry = this_oop->resolved_string_at(which);

     }

   }

   assert(java_lang_String::is_instance(entry), "must be string");

   return entry;

 }

 bool constantPoolOopDesc::is_pseudo_string_at(int which) {

   oop entry = *(obj_at_addr(which));

   if (entry->is_symbol())

     // Not yet resolved, but it will resolve to a string.

     return false;

   else if (java_lang_String::is_instance(entry))

     return false; // actually, it might be a non-interned or non-perm string

   else

     // truly pseudo

     return true;

 }

 bool constantPoolOopDesc::klass_name_at_matches(instanceKlassHandle k,

                                                 int which) {

   // Names are interned, so we can compare symbolOops directly

   symbolOop cp_name = klass_name_at(which);

   return (cp_name == k->name());

 }

 int constantPoolOopDesc::pre_resolve_shared_klasses(TRAPS) {

   ResourceMark rm;

   int count = 0;

   for (int index = 1; index < tags()->length(); index++) { // Index 0 is unused

     if (tag_at(index).is_unresolved_string()) {

       // Intern string

       symbolOop sym = unresolved_string_at(index);

       oop entry = StringTable::intern(sym, CHECK_(-1));

       string_at_put(index, entry);

     }

   }

   return count;

 }

 // Iterate over symbols which are used as class, field, method names and

 // signatures (in preparation for writing to the shared archive).

 void constantPoolOopDesc::shared_symbols_iterate(OopClosure* closure) {

   for (int index = 1; index < length(); index++) { // Index 0 is unused

     switch (tag_at(index).value()) {

     case JVM_CONSTANT_UnresolvedClass:

       closure->do_oop(obj_at_addr(index));

       break;

     case JVM_CONSTANT_NameAndType:

       {

         int i = *int_at_addr(index);

         closure->do_oop(obj_at_addr((unsigned)i >> 16));

         closure->do_oop(obj_at_addr((unsigned)i & 0xffff));

       }

       break;

     case JVM_CONSTANT_Class:

     case JVM_CONSTANT_InterfaceMethodref:

     case JVM_CONSTANT_Fieldref:

     case JVM_CONSTANT_Methodref:

     case JVM_CONSTANT_Integer:

     case JVM_CONSTANT_Float:

       // Do nothing!  Not an oop.

       // These constant types do not reference symbols at this point.

       break;

     case JVM_CONSTANT_String:

       // Do nothing!  Not a symbol.

       break;

     case JVM_CONSTANT_UnresolvedString:

     case JVM_CONSTANT_Utf8:

       // These constants are symbols, but unless these symbols are

       // actually to be used for something, we don't want to mark them.

       break;

     case JVM_CONSTANT_Long:

     case JVM_CONSTANT_Double:

       // Do nothing!  Not an oop. (But takes two pool entries.)

       ++index;

       break;

     default:

       ShouldNotReachHere();

       break;

     }

   }

 }

 // Iterate over the [one] tags array (in preparation for writing to the

 // shared archive).

 void constantPoolOopDesc::shared_tags_iterate(OopClosure* closure) {

   closure->do_oop(tags_addr());

 }

 // Iterate over String objects (in preparation for writing to the shared

 // archive).

 void constantPoolOopDesc::shared_strings_iterate(OopClosure* closure) {

   for (int index = 1; index < length(); index++) { // Index 0 is unused

     switch (tag_at(index).value()) {

     case JVM_CONSTANT_UnresolvedClass:

     case JVM_CONSTANT_NameAndType:

       // Do nothing!  Not a String.

       break;

     case JVM_CONSTANT_Class:

     case JVM_CONSTANT_InterfaceMethodref:

     case JVM_CONSTANT_Fieldref:

     case JVM_CONSTANT_Methodref:

     case JVM_CONSTANT_Integer:

     case JVM_CONSTANT_Float:

       // Do nothing!  Not an oop.

       // These constant types do not reference symbols at this point.

       break;

     case JVM_CONSTANT_String:

       closure->do_oop(obj_at_addr(index));

       break;

     case JVM_CONSTANT_UnresolvedString:

     case JVM_CONSTANT_Utf8:

       // These constants are symbols, but unless these symbols are

       // actually to be used for something, we don't want to mark them.

       break;

     case JVM_CONSTANT_Long:

     case JVM_CONSTANT_Double:

       // Do nothing!  Not an oop. (But takes two pool entries.)

       ++index;

       break;

     default:

       ShouldNotReachHere();

       break;

     }

   }

 }

 // Compare this constant pool's entry at index1 to the constant pool

 // cp2's entry at index2.

 bool constantPoolOopDesc::compare_entry_to(int index1, constantPoolHandle cp2,

        int index2, TRAPS) {

   jbyte t1 = tag_at(index1).value();

   jbyte t2 = cp2->tag_at(index2).value();

   // JVM_CONSTANT_UnresolvedClassInError is equal to JVM_CONSTANT_UnresolvedClass

   // when comparing

   if (t1 == JVM_CONSTANT_UnresolvedClassInError) {

     t1 = JVM_CONSTANT_UnresolvedClass;

   }

   if (t2 == JVM_CONSTANT_UnresolvedClassInError) {

     t2 = JVM_CONSTANT_UnresolvedClass;

   }

   if (t1 != t2) {

     // Not the same entry type so there is nothing else to check. Note

     // that this style of checking will consider resolved/unresolved

     // class pairs and resolved/unresolved string pairs as different.

     // From the constantPoolOop API point of view, this is correct

     // behavior. See constantPoolKlass::merge() to see how this plays

     // out in the context of constantPoolOop merging.

     return false;

   }

   switch (t1) {

   case JVM_CONSTANT_Class:

   {

     klassOop k1 = klass_at(index1, CHECK_false);

     klassOop k2 = cp2->klass_at(index2, CHECK_false);

     if (k1 == k2) {

       return true;

     }

   } break;

   case JVM_CONSTANT_ClassIndex:

   {

     int recur1 = klass_index_at(index1);

     int recur2 = cp2->klass_index_at(index2);

     bool match = compare_entry_to(recur1, cp2, recur2, CHECK_false);

     if (match) {

       return true;

     }

   } break;

   case JVM_CONSTANT_Double:

   {

     jdouble d1 = double_at(index1);

     jdouble d2 = cp2->double_at(index2);

     if (d1 == d2) {

       return true;

     }

   } break;

   case JVM_CONSTANT_Fieldref:

   case JVM_CONSTANT_InterfaceMethodref:

   case JVM_CONSTANT_Methodref:

   {

     int recur1 = uncached_klass_ref_index_at(index1);

     int recur2 = cp2->uncached_klass_ref_index_at(index2);

     bool match = compare_entry_to(recur1, cp2, recur2, CHECK_false);

     if (match) {

       recur1 = uncached_name_and_type_ref_index_at(index1);

       recur2 = cp2->uncached_name_and_type_ref_index_at(index2);

       match = compare_entry_to(recur1, cp2, recur2, CHECK_false);

       if (match) {

         return true;

       }

     }

   } break;

   case JVM_CONSTANT_Float:

   {

     jfloat f1 = float_at(index1);

     jfloat f2 = cp2->float_at(index2);

     if (f1 == f2) {

       return true;

     }

   } break;

   case JVM_CONSTANT_Integer:

   {

     jint i1 = int_at(index1);

     jint i2 = cp2->int_at(index2);

     if (i1 == i2) {

       return true;

     }

   } break;

   case JVM_CONSTANT_Long:

   {

     jlong l1 = long_at(index1);

     jlong l2 = cp2->long_at(index2);

     if (l1 == l2) {

       return true;

     }

   } break;

   case JVM_CONSTANT_NameAndType:

   {

     int recur1 = name_ref_index_at(index1);

     int recur2 = cp2->name_ref_index_at(index2);

     bool match = compare_entry_to(recur1, cp2, recur2, CHECK_false);

     if (match) {

       recur1 = signature_ref_index_at(index1);

       recur2 = cp2->signature_ref_index_at(index2);

       match = compare_entry_to(recur1, cp2, recur2, CHECK_false);

       if (match) {

         return true;

       }

     }

   } break;

   case JVM_CONSTANT_String:

   {

     oop s1 = string_at(index1, CHECK_false);

     oop s2 = cp2->string_at(index2, CHECK_false);

     if (s1 == s2) {

       return true;

     }

   } break;

   case JVM_CONSTANT_StringIndex:

   {

     int recur1 = string_index_at(index1);

     int recur2 = cp2->string_index_at(index2);

     bool match = compare_entry_to(recur1, cp2, recur2, CHECK_false);

     if (match) {

       return true;

     }

   } break;

   case JVM_CONSTANT_UnresolvedClass:

   {

     symbolOop k1 = unresolved_klass_at(index1);

     symbolOop k2 = cp2->unresolved_klass_at(index2);

     if (k1 == k2) {

       return true;

     }

   } break;

   case JVM_CONSTANT_UnresolvedString:

   {

     symbolOop s1 = unresolved_string_at(index1);

     symbolOop s2 = cp2->unresolved_string_at(index2);

     if (s1 == s2) {

       return true;

     }

   } break;

   case JVM_CONSTANT_Utf8:

   {

     symbolOop s1 = symbol_at(index1);

     symbolOop s2 = cp2->symbol_at(index2);

     if (s1 == s2) {

       return true;

     }

   } break;

   // Invalid is used as the tag for the second constant pool entry

   // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should

   // not be seen by itself.

   case JVM_CONSTANT_Invalid: // fall through

   default:

     ShouldNotReachHere();

     break;

   }

   return false;

 } // end compare_entry_to()

 // Copy this constant pool's entries at start_i to end_i (inclusive)

 // to the constant pool to_cp's entries starting at to_i. A total of

 // (end_i - start_i) + 1 entries are copied.

 void constantPoolOopDesc::copy_cp_to(int start_i, int end_i,

        constantPoolHandle to_cp, int to_i, TRAPS) {

   int dest_i = to_i;  // leave original alone for debug purposes

   for (int src_i = start_i; src_i <= end_i; /* see loop bottom */ ) {

     copy_entry_to(src_i, to_cp, dest_i, CHECK);

     switch (tag_at(src_i).value()) {

     case JVM_CONSTANT_Double:

     case JVM_CONSTANT_Long:

       // double and long take two constant pool entries

       src_i += 2;

       dest_i += 2;

       break;

     default:

       // all others take one constant pool entry

       src_i++;

       dest_i++;

       break;

     }

   }

 } // end copy_cp_to()

 // Copy this constant pool's entry at from_i to the constant pool

 // to_cp's entry at to_i.

 void constantPoolOopDesc::copy_entry_to(int from_i, constantPoolHandle to_cp,

        int to_i, TRAPS) {

   switch (tag_at(from_i).value()) {

   case JVM_CONSTANT_Class:

   {

     klassOop k = klass_at(from_i, CHECK);

     to_cp->klass_at_put(to_i, k);

   } break;

   case JVM_CONSTANT_ClassIndex:

   {

     jint ki = klass_index_at(from_i);

     to_cp->klass_index_at_put(to_i, ki);

   } break;

   case JVM_CONSTANT_Double:

   {

     jdouble d = double_at(from_i);

     to_cp->double_at_put(to_i, d);

     // double takes two constant pool entries so init second entry's tag

     to_cp->tag_at_put(to_i + 1, JVM_CONSTANT_Invalid);

   } break;

   case JVM_CONSTANT_Fieldref:

   {

     int class_index = uncached_klass_ref_index_at(from_i);

     int name_and_type_index = uncached_name_and_type_ref_index_at(from_i);

     to_cp->field_at_put(to_i, class_index, name_and_type_index);

   } break;

   case JVM_CONSTANT_Float:

   {

     jfloat f = float_at(from_i);

     to_cp->float_at_put(to_i, f);

   } break;

   case JVM_CONSTANT_Integer:

   {

     jint i = int_at(from_i);

     to_cp->int_at_put(to_i, i);

   } break;

   case JVM_CONSTANT_InterfaceMethodref:

   {

     int class_index = uncached_klass_ref_index_at(from_i);

     int name_and_type_index = uncached_name_and_type_ref_index_at(from_i);

     to_cp->interface_method_at_put(to_i, class_index, name_and_type_index);

   } break;

   case JVM_CONSTANT_Long:

   {

     jlong l = long_at(from_i);

     to_cp->long_at_put(to_i, l);

     // long takes two constant pool entries so init second entry's tag

     to_cp->tag_at_put(to_i + 1, JVM_CONSTANT_Invalid);

   } break;

   case JVM_CONSTANT_Methodref:

   {

     int class_index = uncached_klass_ref_index_at(from_i);

     int name_and_type_index = uncached_name_and_type_ref_index_at(from_i);

     to_cp->method_at_put(to_i, class_index, name_and_type_index);

   } break;

   case JVM_CONSTANT_NameAndType:

   {

     int name_ref_index = name_ref_index_at(from_i);

     int signature_ref_index = signature_ref_index_at(from_i);

     to_cp->name_and_type_at_put(to_i, name_ref_index, signature_ref_index);

   } break;

   case JVM_CONSTANT_String:

   {

     oop s = string_at(from_i, CHECK);

     to_cp->string_at_put(to_i, s);

   } break;

   case JVM_CONSTANT_StringIndex:

   {

     jint si = string_index_at(from_i);

     to_cp->string_index_at_put(to_i, si);

   } break;

   case JVM_CONSTANT_UnresolvedClass:

   {

     symbolOop k = unresolved_klass_at(from_i);

     to_cp->unresolved_klass_at_put(to_i, k);

   } break;

   case JVM_CONSTANT_UnresolvedClassInError:

   {

     symbolOop k = unresolved_klass_at(from_i);

     to_cp->unresolved_klass_at_put(to_i, k);

     to_cp->tag_at_put(to_i, JVM_CONSTANT_UnresolvedClassInError);

   } break;

   case JVM_CONSTANT_UnresolvedString:

   {

     symbolOop s = unresolved_string_at(from_i);

     to_cp->unresolved_string_at_put(to_i, s);

   } break;

   case JVM_CONSTANT_Utf8:

   {

     symbolOop s = symbol_at(from_i);

     to_cp->symbol_at_put(to_i, s);

   } break;

   // Invalid is used as the tag for the second constant pool entry

   // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should

   // not be seen by itself.

   case JVM_CONSTANT_Invalid: // fall through

   default:

   {

     jbyte bad_value = tag_at(from_i).value(); // leave a breadcrumb

     ShouldNotReachHere();

   } break;

   }

 } // end copy_entry_to()

 // Search constant pool search_cp for an entry that matches this

 // constant pool's entry at pattern_i. Returns the index of a

 // matching entry or zero (0) if there is no matching entry.

 int constantPoolOopDesc::find_matching_entry(int pattern_i,

       constantPoolHandle search_cp, TRAPS) {

   // index zero (0) is not used

   for (int i = 1; i < search_cp->length(); i++) {

     bool found = compare_entry_to(pattern_i, search_cp, i, CHECK_0);

     if (found) {

       return i;

     }

   }

   return 0;  // entry not found; return unused index zero (0)

 } // end find_matching_entry()

 #ifndef PRODUCT

 const char* constantPoolOopDesc::printable_name_at(int which) {

   constantTag tag = tag_at(which);

   if (tag.is_unresolved_string() || tag.is_string()) {

     return string_at_noresolve(which);

   } else if (tag.is_klass() || tag.is_unresolved_klass()) {

     return klass_name_at(which)->as_C_string();

   } else if (tag.is_symbol()) {

     return symbol_at(which)->as_C_string();

   }

   return "";

 }

 #endif // PRODUCT

 // JVMTI GetConstantPool support

 // For temporary use until code is stable.

 #define DBG(code)

 static const char* WARN_MSG = "Must not be such entry!";

 static void print_cpool_bytes(jint cnt, u1 *bytes) {

   jint size = 0;

   u2   idx1, idx2;

   for (jint idx = 1; idx < cnt; idx++) {

     jint ent_size = 0;

     u1   tag  = *bytes++;

     size++;                       // count tag

     printf("const #%03d, tag: %02d ", idx, tag);

     switch(tag) {

       case JVM_CONSTANT_Invalid: {

         printf("Invalid");

         break;

       }

       case JVM_CONSTANT_Unicode: {

         printf("Unicode      %s", WARN_MSG);

         break;

       }

       case JVM_CONSTANT_Utf8: {

         u2 len = Bytes::get_Java_u2(bytes);

         char str[128];

         if (len > 127) {

            len = 127;

         }

         strncpy(str, (char *) (bytes+2), len);

         str[len] = '\0';

         printf("Utf8          \"%s\"", str);

         ent_size = 2 + len;

         break;

       }

       case JVM_CONSTANT_Integer: {

         u4 val = Bytes::get_Java_u4(bytes);

         printf("int          %d", *(int *) &val);

         ent_size = 4;

         break;

       }

       case JVM_CONSTANT_Float: {

         u4 val = Bytes::get_Java_u4(bytes);

         printf("float        %5.3ff", *(float *) &val);

         ent_size = 4;

         break;

       }

       case JVM_CONSTANT_Long: {

         u8 val = Bytes::get_Java_u8(bytes);

         printf("long         "INT64_FORMAT, *(jlong *) &val);

         ent_size = 8;

         idx++; // Long takes two cpool slots

         break;

       }

       case JVM_CONSTANT_Double: {

         u8 val = Bytes::get_Java_u8(bytes);

         printf("double       %5.3fd", *(jdouble *)&val);

         ent_size = 8;

         idx++; // Double takes two cpool slots

         break;

       }

       case JVM_CONSTANT_Class: {

         idx1 = Bytes::get_Java_u2(bytes);

         printf("class        #%03d", idx1);

         ent_size = 2;

         break;

       }

       case JVM_CONSTANT_String: {

         idx1 = Bytes::get_Java_u2(bytes);

         printf("String       #%03d", idx1);

         ent_size = 2;

         break;

       }

       case JVM_CONSTANT_Fieldref: {

         idx1 = Bytes::get_Java_u2(bytes);

         idx2 = Bytes::get_Java_u2(bytes+2);

         printf("Field        #%03d, #%03d", (int) idx1, (int) idx2);

         ent_size = 4;

         break;

       }

       case JVM_CONSTANT_Methodref: {

         idx1 = Bytes::get_Java_u2(bytes);

         idx2 = Bytes::get_Java_u2(bytes+2);

         printf("Method       #%03d, #%03d", idx1, idx2);

         ent_size = 4;

         break;

       }

       case JVM_CONSTANT_InterfaceMethodref: {

         idx1 = Bytes::get_Java_u2(bytes);

         idx2 = Bytes::get_Java_u2(bytes+2);

         printf("InterfMethod #%03d, #%03d", idx1, idx2);

         ent_size = 4;

         break;

       }

       case JVM_CONSTANT_NameAndType: {

         idx1 = Bytes::get_Java_u2(bytes);

         idx2 = Bytes::get_Java_u2(bytes+2);

         printf("NameAndType  #%03d, #%03d", idx1, idx2);

         ent_size = 4;

         break;

       }

       case JVM_CONSTANT_ClassIndex: {

         printf("ClassIndex  %s", WARN_MSG);

         break;

       }

       case JVM_CONSTANT_UnresolvedClass: {

         printf("UnresolvedClass: %s", WARN_MSG);

         break;

       }

       case JVM_CONSTANT_UnresolvedClassInError: {

         printf("UnresolvedClassInErr: %s", WARN_MSG);

         break;

       }

       case JVM_CONSTANT_StringIndex: {

         printf("StringIndex: %s", WARN_MSG);

         break;

       }

       case JVM_CONSTANT_UnresolvedString: {

         printf("UnresolvedString: %s", WARN_MSG);

         break;

       }

     }

     printf(";\n");

     bytes += ent_size;

     size  += ent_size;

   }

   printf("Cpool size: %d\n", size);

   fflush(0);

   return;

 } /* end print_cpool_bytes */

 // Returns size of constant pool entry.

 jint constantPoolOopDesc::cpool_entry_size(jint idx) {

   switch(tag_at(idx).value()) {

     case JVM_CONSTANT_Invalid:

     case JVM_CONSTANT_Unicode:

       return 1;

     case JVM_CONSTANT_Utf8:

       return 3 + symbol_at(idx)->utf8_length();

     case JVM_CONSTANT_Class:

     case JVM_CONSTANT_String:

     case JVM_CONSTANT_ClassIndex:

     case JVM_CONSTANT_UnresolvedClass:

     case JVM_CONSTANT_UnresolvedClassInError:

     case JVM_CONSTANT_StringIndex:

     case JVM_CONSTANT_UnresolvedString:

       return 3;

     case JVM_CONSTANT_Integer:

     case JVM_CONSTANT_Float:

     case JVM_CONSTANT_Fieldref:

     case JVM_CONSTANT_Methodref:

     case JVM_CONSTANT_InterfaceMethodref:

     case JVM_CONSTANT_NameAndType:

       return 5;

     case JVM_CONSTANT_Long:

     case JVM_CONSTANT_Double:

       return 9;

   }

   assert(false, "cpool_entry_size: Invalid constant pool entry tag");

   return 1;

 } /* end cpool_entry_size */

 // SymbolHashMap is used to find a constant pool index from a string.

 // This function fills in SymbolHashMaps, one for utf8s and one for

 // class names, returns size of the cpool raw bytes.

 jint constantPoolOopDesc::hash_entries_to(SymbolHashMap *symmap,

                                           SymbolHashMap *classmap) {

   jint size = 0;

   for (u2 idx = 1; idx < length(); idx++) {

     u2 tag = tag_at(idx).value();

     size += cpool_entry_size(idx);

     switch(tag) {

       case JVM_CONSTANT_Utf8: {

         symbolOop sym = symbol_at(idx);

         symmap->add_entry(sym, idx);

         DBG(printf("adding symbol entry %s = %d\n", sym->as_utf8(), idx));

         break;

       }

       case JVM_CONSTANT_Class:

       case JVM_CONSTANT_UnresolvedClass:

       case JVM_CONSTANT_UnresolvedClassInError: {

         symbolOop sym = klass_name_at(idx);

         classmap->add_entry(sym, idx);

         DBG(printf("adding class entry %s = %d\n", sym->as_utf8(), idx));

         break;

       }

       case JVM_CONSTANT_Long:

       case JVM_CONSTANT_Double: {

         idx++; // Both Long and Double take two cpool slots

         break;

       }

     }

   }

   return size;

 } /* end hash_utf8_entries_to */

 // Copy cpool bytes.

 // Returns:

 //    0, in case of OutOfMemoryError

 //   -1, in case of internal error

 //  > 0, count of the raw cpool bytes that have been copied

 int constantPoolOopDesc::copy_cpool_bytes(int cpool_size,

                                           SymbolHashMap* tbl,

                                           unsigned char *bytes) {

   u2   idx1, idx2;

   jint size  = 0;

   jint cnt   = length();

   unsigned char *start_bytes = bytes;

   for (jint idx = 1; idx < cnt; idx++) {

     u1   tag      = tag_at(idx).value();

     jint ent_size = cpool_entry_size(idx);

     assert(size + ent_size <= cpool_size, "Size mismatch");

     *bytes = tag;

     DBG(printf("#%03hd tag=%03hd, ", idx, tag));

     switch(tag) {

       case JVM_CONSTANT_Invalid: {

         DBG(printf("JVM_CONSTANT_Invalid"));

         break;

       }

       case JVM_CONSTANT_Unicode: {

         assert(false, "Wrong constant pool tag: JVM_CONSTANT_Unicode");

         DBG(printf("JVM_CONSTANT_Unicode"));

         break;

       }

       case JVM_CONSTANT_Utf8: {

         symbolOop sym = symbol_at(idx);

         char*     str = sym->as_utf8();

         // Warning! It's crashing on x86 with len = sym->utf8_length()

         int       len = (int) strlen(str);

         Bytes::put_Java_u2((address) (bytes+1), (u2) len);

         for (int i = 0; i < len; i++) {

             bytes[3+i] = (u1) str[i];

         }

         DBG(printf("JVM_CONSTANT_Utf8: %s ", str));

         break;

       }

       case JVM_CONSTANT_Integer: {

         jint val = int_at(idx);

         Bytes::put_Java_u4((address) (bytes+1), *(u4*)&val);

         break;

       }

       case JVM_CONSTANT_Float: {

         jfloat val = float_at(idx);

         Bytes::put_Java_u4((address) (bytes+1), *(u4*)&val);

         break;

       }

       case JVM_CONSTANT_Long: {

         jlong val = long_at(idx);

         Bytes::put_Java_u8((address) (bytes+1), *(u8*)&val);

         idx++;             // Long takes two cpool slots

         break;

       }

       case JVM_CONSTANT_Double: {

         jdouble val = double_at(idx);

         Bytes::put_Java_u8((address) (bytes+1), *(u8*)&val);

         idx++;             // Double takes two cpool slots

         break;

       }

       case JVM_CONSTANT_Class:

       case JVM_CONSTANT_UnresolvedClass:

       case JVM_CONSTANT_UnresolvedClassInError: {

         *bytes = JVM_CONSTANT_Class;

         symbolOop sym = klass_name_at(idx);

         idx1 = tbl->symbol_to_value(sym);

         assert(idx1 != 0, "Have not found a hashtable entry");

         Bytes::put_Java_u2((address) (bytes+1), idx1);

         DBG(printf("JVM_CONSTANT_Class: idx=#%03hd, %s", idx1, sym->as_utf8()));

         break;

       }

       case JVM_CONSTANT_String: {

         unsigned int hash;

         char *str = string_at_noresolve(idx);

         symbolOop sym = SymbolTable::lookup_only(str, (int) strlen(str), hash);

         if (sym == NULL) {

           // sym can be NULL if string refers to incorrectly encoded JVM_CONSTANT_Utf8

           // this can happen with JVM TI; see CR 6839599 for more details

           oop string = *(obj_at_addr(idx));

           assert(java_lang_String::is_instance(string),"Not a String");

           DBG(printf("Error #%03hd tag=%03hd\n", idx, tag));

           idx1 = 0;

           for (int j = 0; j < tbl->table_size() && idx1 == 0; j++) {

             for (SymbolHashMapEntry* cur = tbl->bucket(j); cur != NULL; cur = cur->next()) {

               int length;

               sym = cur->symbol();

               jchar* chars = sym->as_unicode(length);

               if (java_lang_String::equals(string, chars, length)) {

                 idx1 = cur->value();

                 DBG(printf("Index found: %d\n",idx1));

                 break;

               }

             }

           }

         } else {

           idx1 = tbl->symbol_to_value(sym);

         }

         assert(idx1 != 0, "Have not found a hashtable entry");

         Bytes::put_Java_u2((address) (bytes+1), idx1);

         DBG(printf("JVM_CONSTANT_String: idx=#%03hd, %s", idx1, str));

         break;

       }

       case JVM_CONSTANT_UnresolvedString: {

         *bytes = JVM_CONSTANT_String;

         symbolOop sym = unresolved_string_at(idx);

         idx1 = tbl->symbol_to_value(sym);

         assert(idx1 != 0, "Have not found a hashtable entry");

         Bytes::put_Java_u2((address) (bytes+1), idx1);

         DBG(char *str = sym->as_utf8());

         DBG(printf("JVM_CONSTANT_UnresolvedString: idx=#%03hd, %s", idx1, str));

         break;

       }

       case JVM_CONSTANT_Fieldref:

       case JVM_CONSTANT_Methodref:

       case JVM_CONSTANT_InterfaceMethodref: {

         idx1 = uncached_klass_ref_index_at(idx);

         idx2 = uncached_name_and_type_ref_index_at(idx);

         Bytes::put_Java_u2((address) (bytes+1), idx1);

         Bytes::put_Java_u2((address) (bytes+3), idx2);

         DBG(printf("JVM_CONSTANT_Methodref: %hd %hd", idx1, idx2));

         break;

       }

       case JVM_CONSTANT_NameAndType: {

         idx1 = name_ref_index_at(idx);

         idx2 = signature_ref_index_at(idx);

         Bytes::put_Java_u2((address) (bytes+1), idx1);

         Bytes::put_Java_u2((address) (bytes+3), idx2);

         DBG(printf("JVM_CONSTANT_NameAndType: %hd %hd", idx1, idx2));

         break;

       }

       case JVM_CONSTANT_ClassIndex: {

         *bytes = JVM_CONSTANT_Class;

         idx1 = klass_index_at(idx);

         Bytes::put_Java_u2((address) (bytes+1), idx1);

         DBG(printf("JVM_CONSTANT_ClassIndex: %hd", idx1));

         break;

       }

       case JVM_CONSTANT_StringIndex: {

         *bytes = JVM_CONSTANT_String;

         idx1 = string_index_at(idx);

         Bytes::put_Java_u2((address) (bytes+1), idx1);

         DBG(printf("JVM_CONSTANT_StringIndex: %hd", idx1));

         break;

       }

     }

     DBG(printf("\n"));

     bytes += ent_size;

     size  += ent_size;

   }

   assert(size == cpool_size, "Size mismatch");

   // Keep temorarily for debugging until it's stable.

   DBG(print_cpool_bytes(cnt, start_bytes));

   return (int)(bytes - start_bytes);

 } /* end copy_cpool_bytes */

 void SymbolHashMap::add_entry(symbolOop sym, u2 value) {

   char *str = sym->as_utf8();

   unsigned int hash = compute_hash(str, sym->utf8_length());

   unsigned int index = hash % table_size();

   // check if already in map

   // we prefer the first entry since it is more likely to be what was used in

   // the class file

   for (SymbolHashMapEntry *en = bucket(index); en != NULL; en = en->next()) {

     assert(en->symbol() != NULL, "SymbolHashMapEntry symbol is NULL");

     if (en->hash() == hash && en->symbol() == sym) {

         return;  // already there

     }

   }

   SymbolHashMapEntry* entry = new SymbolHashMapEntry(hash, sym, value);

   entry->set_next(bucket(index));

   _buckets[index].set_entry(entry);

   assert(entry->symbol() != NULL, "SymbolHashMapEntry symbol is NULL");

 }

 SymbolHashMapEntry* SymbolHashMap::find_entry(symbolOop sym) {

   assert(sym != NULL, "SymbolHashMap::find_entry - symbol is NULL");

   char *str = sym->as_utf8();

   int   len = sym->utf8_length();

   unsigned int hash = SymbolHashMap::compute_hash(str, len);

   unsigned int index = hash % table_size();

   for (SymbolHashMapEntry *en = bucket(index); en != NULL; en = en->next()) {

     assert(en->symbol() != NULL, "SymbolHashMapEntry symbol is NULL");

     if (en->hash() == hash && en->symbol() == sym) {

       return en;

     }

   }

   return NULL;

 }