1 /*
   2  * Copyright (c) 1998, 2015, 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 "gc_implementation/shared/markSweep.inline.hpp"
  27 #include "interpreter/interpreter.hpp"
  28 #include "interpreter/rewriter.hpp"
  29 #include "memory/universe.inline.hpp"
  30 #include "oops/cpCache.hpp"
  31 #include "oops/objArrayOop.hpp"
  32 #include "oops/oop.inline.hpp"
  33 #include "prims/jvmtiRedefineClassesTrace.hpp"
  34 #include "prims/methodHandles.hpp"
  35 #include "runtime/atomic.inline.hpp"
  36 #include "runtime/handles.inline.hpp"
  37 #include "runtime/orderAccess.inline.hpp"
  38 #include "utilities/macros.hpp"
  39 #if INCLUDE_ALL_GCS
  40 # include "gc_implementation/parallelScavenge/psPromotionManager.hpp"
  41 #endif // INCLUDE_ALL_GCS
  42 
  43 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  44 
  45 // Implementation of ConstantPoolCacheEntry
  46 
  47 void ConstantPoolCacheEntry::initialize_entry(int index) {
  48   assert(0 < index && index < 0x10000, "sanity check");
  49   _indices = index;
  50   _f1 = NULL;
  51   _f2 = _flags = 0;
  52   assert(constant_pool_index() == index, "");
  53 }
  54 
  55 int ConstantPoolCacheEntry::make_flags(TosState state,
  56                                        int option_bits,
  57                                        int field_index_or_method_params) {
  58   assert(state < number_of_states, "Invalid state in make_flags");
  59   int f = ((int)state << tos_state_shift) | option_bits | field_index_or_method_params;
  60   // Preserve existing flag bit values
  61   // The low bits are a field offset, or else the method parameter size.
  62 #ifdef ASSERT
  63   TosState old_state = flag_state();
  64   assert(old_state == (TosState)0 || old_state == state,
  65          "inconsistent cpCache flags state");
  66 #endif
  67   return (_flags | f) ;
  68 }
  69 
  70 void ConstantPoolCacheEntry::set_bytecode_1(Bytecodes::Code code) {
  71 #ifdef ASSERT
  72   // Read once.
  73   volatile Bytecodes::Code c = bytecode_1();
  74   assert(c == 0 || c == code || code == 0, "update must be consistent");
  75 #endif
  76   // Need to flush pending stores here before bytecode is written.
  77   OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << bytecode_1_shift));
  78 }
  79 
  80 void ConstantPoolCacheEntry::set_bytecode_2(Bytecodes::Code code) {
  81 #ifdef ASSERT
  82   // Read once.
  83   volatile Bytecodes::Code c = bytecode_2();
  84   assert(c == 0 || c == code || code == 0, "update must be consistent");
  85 #endif
  86   // Need to flush pending stores here before bytecode is written.
  87   OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << bytecode_2_shift));
  88 }
  89 
  90 // Sets f1, ordering with previous writes.
  91 void ConstantPoolCacheEntry::release_set_f1(Metadata* f1) {
  92   assert(f1 != NULL, "");
  93   OrderAccess::release_store_ptr((HeapWord*) &_f1, f1);
  94 }
  95 
  96 // Sets flags, but only if the value was previously zero.
  97 bool ConstantPoolCacheEntry::init_flags_atomic(intptr_t flags) {
  98   intptr_t result = Atomic::cmpxchg_ptr(flags, &_flags, 0);
  99   return (result == 0);
 100 }
 101 
 102 // Note that concurrent update of both bytecodes can leave one of them
 103 // reset to zero.  This is harmless; the interpreter will simply re-resolve
 104 // the damaged entry.  More seriously, the memory synchronization is needed
 105 // to flush other fields (f1, f2) completely to memory before the bytecodes
 106 // are updated, lest other processors see a non-zero bytecode but zero f1/f2.
 107 void ConstantPoolCacheEntry::set_field(Bytecodes::Code get_code,
 108                                        Bytecodes::Code put_code,
 109                                        KlassHandle field_holder,
 110                                        int field_index,
 111                                        int field_offset,
 112                                        TosState field_type,
 113                                        bool is_final,
 114                                        bool is_volatile,
 115                                        Klass* root_klass) {
 116   set_f1(field_holder());
 117   set_f2(field_offset);
 118   assert((field_index & field_index_mask) == field_index,
 119          "field index does not fit in low flag bits");
 120   set_field_flags(field_type,
 121                   ((is_volatile ? 1 : 0) << is_volatile_shift) |
 122                   ((is_final    ? 1 : 0) << is_final_shift),
 123                   field_index);
 124   set_bytecode_1(get_code);
 125   set_bytecode_2(put_code);
 126   NOT_PRODUCT(verify(tty));
 127 }
 128 
 129 void ConstantPoolCacheEntry::set_parameter_size(int value) {
 130   // This routine is called only in corner cases where the CPCE is not yet initialized.
 131   // See AbstractInterpreter::deopt_continue_after_entry.
 132   assert(_flags == 0 || parameter_size() == 0 || parameter_size() == value,
 133          err_msg("size must not change: parameter_size=%d, value=%d", parameter_size(), value));
 134   // Setting the parameter size by itself is only safe if the
 135   // current value of _flags is 0, otherwise another thread may have
 136   // updated it and we don't want to overwrite that value.  Don't
 137   // bother trying to update it once it's nonzero but always make
 138   // sure that the final parameter size agrees with what was passed.
 139   if (_flags == 0) {
 140     Atomic::cmpxchg_ptr((value & parameter_size_mask), &_flags, 0);
 141   }
 142   guarantee(parameter_size() == value,
 143             err_msg("size must not change: parameter_size=%d, value=%d", parameter_size(), value));
 144 }
 145 
 146 void ConstantPoolCacheEntry::set_direct_or_vtable_call(Bytecodes::Code invoke_code,
 147                                                        methodHandle method,
 148                                                        int vtable_index) {
 149   bool is_vtable_call = (vtable_index >= 0);  // FIXME: split this method on this boolean
 150   assert(method->interpreter_entry() != NULL, "should have been set at this point");
 151   assert(!method->is_obsolete(),  "attempt to write obsolete method to cpCache");
 152 
 153   int byte_no = -1;
 154   bool change_to_virtual = false;
 155 
 156   switch (invoke_code) {
 157     case Bytecodes::_invokeinterface:
 158       // We get here from InterpreterRuntime::resolve_invoke when an invokeinterface
 159       // instruction somehow links to a non-interface method (in Object).
 160       // In that case, the method has no itable index and must be invoked as a virtual.
 161       // Set a flag to keep track of this corner case.
 162       change_to_virtual = true;
 163 
 164       // ...and fall through as if we were handling invokevirtual:
 165     case Bytecodes::_invokevirtual:
 166       {
 167         if (!is_vtable_call) {
 168           assert(method->can_be_statically_bound(), "");
 169           // set_f2_as_vfinal_method checks if is_vfinal flag is true.
 170           set_method_flags(as_TosState(method->result_type()),
 171                            (                             1      << is_vfinal_shift) |
 172                            ((method->is_final_method() ? 1 : 0) << is_final_shift)  |
 173                            ((change_to_virtual         ? 1 : 0) << is_forced_virtual_shift),
 174                            method()->size_of_parameters());
 175           set_f2_as_vfinal_method(method());
 176         } else {
 177           assert(!method->can_be_statically_bound(), "");
 178           assert(vtable_index >= 0, "valid index");
 179           assert(!method->is_final_method(), "sanity");
 180           set_method_flags(as_TosState(method->result_type()),
 181                            ((change_to_virtual ? 1 : 0) << is_forced_virtual_shift),
 182                            method()->size_of_parameters());
 183           set_f2(vtable_index);
 184         }
 185         byte_no = 2;
 186         break;
 187       }
 188 
 189     case Bytecodes::_invokespecial:
 190     case Bytecodes::_invokestatic:
 191       assert(!is_vtable_call, "");
 192       // Note:  Read and preserve the value of the is_vfinal flag on any
 193       // invokevirtual bytecode shared with this constant pool cache entry.
 194       // It is cheap and safe to consult is_vfinal() at all times.
 195       // Once is_vfinal is set, it must stay that way, lest we get a dangling oop.
 196       set_method_flags(as_TosState(method->result_type()),
 197                        ((is_vfinal()               ? 1 : 0) << is_vfinal_shift) |
 198                        ((method->is_final_method() ? 1 : 0) << is_final_shift),
 199                        method()->size_of_parameters());
 200       set_f1(method());
 201       byte_no = 1;
 202       break;
 203     default:
 204       ShouldNotReachHere();
 205       break;
 206   }
 207 
 208   // Note:  byte_no also appears in TemplateTable::resolve.
 209   if (byte_no == 1) {
 210     assert(invoke_code != Bytecodes::_invokevirtual &&
 211            invoke_code != Bytecodes::_invokeinterface, "");
 212     set_bytecode_1(invoke_code);
 213   } else if (byte_no == 2)  {
 214     if (change_to_virtual) {
 215       assert(invoke_code == Bytecodes::_invokeinterface, "");
 216       // NOTE: THIS IS A HACK - BE VERY CAREFUL!!!
 217       //
 218       // Workaround for the case where we encounter an invokeinterface, but we
 219       // should really have an _invokevirtual since the resolved method is a
 220       // virtual method in java.lang.Object. This is a corner case in the spec
 221       // but is presumably legal. javac does not generate this code.
 222       //
 223       // We set bytecode_1() to _invokeinterface, because that is the
 224       // bytecode # used by the interpreter to see if it is resolved.
 225       // We set bytecode_2() to _invokevirtual.
 226       // See also interpreterRuntime.cpp. (8/25/2000)
 227       // Only set resolved for the invokeinterface case if method is public.
 228       // Otherwise, the method needs to be reresolved with caller for each
 229       // interface call.
 230       if (method->is_public()) set_bytecode_1(invoke_code);
 231     } else {
 232       assert(invoke_code == Bytecodes::_invokevirtual, "");
 233     }
 234     // set up for invokevirtual, even if linking for invokeinterface also:
 235     set_bytecode_2(Bytecodes::_invokevirtual);
 236   } else {
 237     ShouldNotReachHere();
 238   }
 239   NOT_PRODUCT(verify(tty));
 240 }
 241 
 242 void ConstantPoolCacheEntry::set_direct_call(Bytecodes::Code invoke_code, methodHandle method) {
 243   int index = Method::nonvirtual_vtable_index;
 244   // index < 0; FIXME: inline and customize set_direct_or_vtable_call
 245   set_direct_or_vtable_call(invoke_code, method, index);
 246 }
 247 
 248 void ConstantPoolCacheEntry::set_vtable_call(Bytecodes::Code invoke_code, methodHandle method, int index) {
 249   // either the method is a miranda or its holder should accept the given index
 250   assert(method->method_holder()->is_interface() || method->method_holder()->verify_vtable_index(index), "");
 251   // index >= 0; FIXME: inline and customize set_direct_or_vtable_call
 252   set_direct_or_vtable_call(invoke_code, method, index);
 253 }
 254 
 255 void ConstantPoolCacheEntry::set_itable_call(Bytecodes::Code invoke_code, methodHandle method, int index) {
 256   assert(method->method_holder()->verify_itable_index(index), "");
 257   assert(invoke_code == Bytecodes::_invokeinterface, "");
 258   InstanceKlass* interf = method->method_holder();
 259   assert(interf->is_interface(), "must be an interface");
 260   assert(!method->is_final_method(), "interfaces do not have final methods; cannot link to one here");
 261   set_f1(interf);
 262   set_f2(index);
 263   set_method_flags(as_TosState(method->result_type()),
 264                    0,  // no option bits
 265                    method()->size_of_parameters());
 266   set_bytecode_1(Bytecodes::_invokeinterface);
 267 }
 268 
 269 
 270 void ConstantPoolCacheEntry::set_method_handle(constantPoolHandle cpool, const CallInfo &call_info) {
 271   set_method_handle_common(cpool, Bytecodes::_invokehandle, call_info);
 272 }
 273 
 274 void ConstantPoolCacheEntry::set_dynamic_call(constantPoolHandle cpool, const CallInfo &call_info) {
 275   set_method_handle_common(cpool, Bytecodes::_invokedynamic, call_info);
 276 }
 277 
 278 void ConstantPoolCacheEntry::set_method_handle_common(constantPoolHandle cpool,
 279                                                       Bytecodes::Code invoke_code,
 280                                                       const CallInfo &call_info) {
 281   // NOTE: This CPCE can be the subject of data races.
 282   // There are three words to update: flags, refs[f2], f1 (in that order).
 283   // Writers must store all other values before f1.
 284   // Readers must test f1 first for non-null before reading other fields.
 285   // Competing writers must acquire exclusive access via a lock.
 286   // A losing writer waits on the lock until the winner writes f1 and leaves
 287   // the lock, so that when the losing writer returns, he can use the linked
 288   // cache entry.
 289 
 290   objArrayHandle resolved_references = cpool->resolved_references();
 291   // Use the resolved_references() lock for this cpCache entry.
 292   // resolved_references are created for all classes with Invokedynamic, MethodHandle
 293   // or MethodType constant pool cache entries.
 294   assert(resolved_references() != NULL,
 295          "a resolved_references array should have been created for this class");
 296   ObjectLocker ol(resolved_references, Thread::current());
 297   if (!is_f1_null()) {
 298     return;
 299   }
 300 
 301   const methodHandle adapter = call_info.resolved_method();
 302   const Handle appendix      = call_info.resolved_appendix();
 303   const Handle method_type   = call_info.resolved_method_type();
 304   const bool has_appendix    = appendix.not_null();
 305   const bool has_method_type = method_type.not_null();
 306 
 307   // Write the flags.
 308   set_method_flags(as_TosState(adapter->result_type()),
 309                    ((has_appendix    ? 1 : 0) << has_appendix_shift   ) |
 310                    ((has_method_type ? 1 : 0) << has_method_type_shift) |
 311                    (                   1      << is_final_shift       ),
 312                    adapter->size_of_parameters());
 313 
 314   if (TraceInvokeDynamic) {
 315     tty->print_cr("set_method_handle bc=%d appendix="PTR_FORMAT"%s method_type="PTR_FORMAT"%s method="PTR_FORMAT" ",
 316                   invoke_code,
 317                   (void *)appendix(),    (has_appendix    ? "" : " (unused)"),
 318                   (void *)method_type(), (has_method_type ? "" : " (unused)"),
 319                   (intptr_t)adapter());
 320     adapter->print();
 321     if (has_appendix)  appendix()->print();
 322   }
 323 
 324   // Method handle invokes and invokedynamic sites use both cp cache words.
 325   // refs[f2], if not null, contains a value passed as a trailing argument to the adapter.
 326   // In the general case, this could be the call site's MethodType,
 327   // for use with java.lang.Invokers.checkExactType, or else a CallSite object.
 328   // f1 contains the adapter method which manages the actual call.
 329   // In the general case, this is a compiled LambdaForm.
 330   // (The Java code is free to optimize these calls by binding other
 331   // sorts of methods and appendices to call sites.)
 332   // JVM-level linking is via f1, as if for invokespecial, and signatures are erased.
 333   // The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.
 334   // Even with the appendix, the method will never take more than 255 parameter slots.
 335   //
 336   // This means that given a call site like (List)mh.invoke("foo"),
 337   // the f1 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',
 338   // not '(Ljava/lang/String;)Ljava/util/List;'.
 339   // The fact that String and List are involved is encoded in the MethodType in refs[f2].
 340   // This allows us to create fewer Methods, while keeping type safety.
 341   //
 342 
 343   // Store appendix, if any.
 344   if (has_appendix) {
 345     const int appendix_index = f2_as_index() + _indy_resolved_references_appendix_offset;
 346     assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");
 347     assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
 348     resolved_references->obj_at_put(appendix_index, appendix());
 349   }
 350 
 351   // Store MethodType, if any.
 352   if (has_method_type) {
 353     const int method_type_index = f2_as_index() + _indy_resolved_references_method_type_offset;
 354     assert(method_type_index >= 0 && method_type_index < resolved_references->length(), "oob");
 355     assert(resolved_references->obj_at(method_type_index) == NULL, "init just once");
 356     resolved_references->obj_at_put(method_type_index, method_type());
 357   }
 358 
 359   release_set_f1(adapter());  // This must be the last one to set (see NOTE above)!
 360 
 361   // The interpreter assembly code does not check byte_2,
 362   // but it is used by is_resolved, method_if_resolved, etc.
 363   set_bytecode_1(invoke_code);
 364   NOT_PRODUCT(verify(tty));
 365   if (TraceInvokeDynamic) {
 366     this->print(tty, 0);
 367   }
 368 }
 369 
 370 Method* ConstantPoolCacheEntry::method_if_resolved(constantPoolHandle cpool) {
 371   // Decode the action of set_method and set_interface_call
 372   Bytecodes::Code invoke_code = bytecode_1();
 373   if (invoke_code != (Bytecodes::Code)0) {
 374     Metadata* f1 = f1_ord();
 375     if (f1 != NULL) {
 376       switch (invoke_code) {
 377       case Bytecodes::_invokeinterface:
 378         assert(f1->is_klass(), "");
 379         return klassItable::method_for_itable_index((Klass*)f1, f2_as_index());
 380       case Bytecodes::_invokestatic:
 381       case Bytecodes::_invokespecial:
 382         assert(!has_appendix(), "");
 383       case Bytecodes::_invokehandle:
 384       case Bytecodes::_invokedynamic:
 385         assert(f1->is_method(), "");
 386         return (Method*)f1;
 387       }
 388     }
 389   }
 390   invoke_code = bytecode_2();
 391   if (invoke_code != (Bytecodes::Code)0) {
 392     switch (invoke_code) {
 393     case Bytecodes::_invokevirtual:
 394       if (is_vfinal()) {
 395         // invokevirtual
 396         Method* m = f2_as_vfinal_method();
 397         assert(m->is_method(), "");
 398         return m;
 399       } else {
 400         int holder_index = cpool->uncached_klass_ref_index_at(constant_pool_index());
 401         if (cpool->tag_at(holder_index).is_klass()) {
 402           Klass* klass = cpool->resolved_klass_at(holder_index);
 403           if (!klass->oop_is_instance())
 404             klass = SystemDictionary::Object_klass();
 405           return InstanceKlass::cast(klass)->method_at_vtable(f2_as_index());
 406         }
 407       }
 408       break;
 409     }
 410   }
 411   return NULL;
 412 }
 413 
 414 
 415 oop ConstantPoolCacheEntry::appendix_if_resolved(constantPoolHandle cpool) {
 416   if (!has_appendix())
 417     return NULL;
 418   const int ref_index = f2_as_index() + _indy_resolved_references_appendix_offset;
 419   objArrayOop resolved_references = cpool->resolved_references();
 420   return resolved_references->obj_at(ref_index);
 421 }
 422 
 423 
 424 oop ConstantPoolCacheEntry::method_type_if_resolved(constantPoolHandle cpool) {
 425   if (!has_method_type())
 426     return NULL;
 427   const int ref_index = f2_as_index() + _indy_resolved_references_method_type_offset;
 428   objArrayOop resolved_references = cpool->resolved_references();
 429   return resolved_references->obj_at(ref_index);
 430 }
 431 
 432 
 433 #if INCLUDE_JVMTI
 434 // RedefineClasses() API support:
 435 // If this ConstantPoolCacheEntry refers to old_method then update it
 436 // to refer to new_method.
 437 bool ConstantPoolCacheEntry::adjust_method_entry(Method* old_method,
 438        Method* new_method, bool * trace_name_printed) {
 439 
 440   if (is_vfinal()) {
 441     // virtual and final so _f2 contains method ptr instead of vtable index
 442     if (f2_as_vfinal_method() == old_method) {
 443       // match old_method so need an update
 444       // NOTE: can't use set_f2_as_vfinal_method as it asserts on different values
 445       _f2 = (intptr_t)new_method;
 446       if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
 447         if (!(*trace_name_printed)) {
 448           // RC_TRACE_MESG macro has an embedded ResourceMark
 449           RC_TRACE_MESG(("adjust: name=%s",
 450             old_method->method_holder()->external_name()));
 451           *trace_name_printed = true;
 452         }
 453         // RC_TRACE macro has an embedded ResourceMark
 454         RC_TRACE(0x00400000, ("cpc vf-entry update: %s(%s)",
 455           new_method->name()->as_C_string(),
 456           new_method->signature()->as_C_string()));
 457       }
 458       return true;
 459     }
 460 
 461     // f1() is not used with virtual entries so bail out
 462     return false;
 463   }
 464 
 465   if (_f1 == NULL) {
 466     // NULL f1() means this is a virtual entry so bail out
 467     // We are assuming that the vtable index does not need change.
 468     return false;
 469   }
 470 
 471   if (_f1 == old_method) {
 472     _f1 = new_method;
 473     if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
 474       if (!(*trace_name_printed)) {
 475         // RC_TRACE_MESG macro has an embedded ResourceMark
 476         RC_TRACE_MESG(("adjust: name=%s",
 477           old_method->method_holder()->external_name()));
 478         *trace_name_printed = true;
 479       }
 480       // RC_TRACE macro has an embedded ResourceMark
 481       RC_TRACE(0x00400000, ("cpc entry update: %s(%s)",
 482         new_method->name()->as_C_string(),
 483         new_method->signature()->as_C_string()));
 484     }
 485     return true;
 486   }
 487 
 488   return false;
 489 }
 490 
 491 // a constant pool cache entry should never contain old or obsolete methods
 492 bool ConstantPoolCacheEntry::check_no_old_or_obsolete_entries() {
 493   if (is_vfinal()) {
 494     // virtual and final so _f2 contains method ptr instead of vtable index
 495     Metadata* f2 = (Metadata*)_f2;
 496     // Return false if _f2 refers to an old or an obsolete method.
 497     // _f2 == NULL || !_f2->is_method() are just as unexpected here.
 498     return (f2 != NULL NOT_PRODUCT(&& f2->is_valid()) && f2->is_method() &&
 499             !((Method*)f2)->is_old() && !((Method*)f2)->is_obsolete());
 500   } else if (_f1 == NULL ||
 501              (NOT_PRODUCT(_f1->is_valid() &&) !_f1->is_method())) {
 502     // _f1 == NULL || !_f1->is_method() are OK here
 503     return true;
 504   }
 505   // return false if _f1 refers to a non-deleted old or obsolete method
 506   return (NOT_PRODUCT(_f1->is_valid() &&) _f1->is_method() &&
 507           (f1_as_method()->is_deleted() ||
 508           (!f1_as_method()->is_old() && !f1_as_method()->is_obsolete())));
 509 }
 510 
 511 Method* ConstantPoolCacheEntry::get_interesting_method_entry(Klass* k) {
 512   if (!is_method_entry()) {
 513     // not a method entry so not interesting by default
 514     return NULL;
 515   }
 516   Method* m = NULL;
 517   if (is_vfinal()) {
 518     // virtual and final so _f2 contains method ptr instead of vtable index
 519     m = f2_as_vfinal_method();
 520   } else if (is_f1_null()) {
 521     // NULL _f1 means this is a virtual entry so also not interesting
 522     return NULL;
 523   } else {
 524     if (!(_f1->is_method())) {
 525       // _f1 can also contain a Klass* for an interface
 526       return NULL;
 527     }
 528     m = f1_as_method();
 529   }
 530   assert(m != NULL && m->is_method(), "sanity check");
 531   if (m == NULL || !m->is_method() || (k != NULL && m->method_holder() != k)) {
 532     // robustness for above sanity checks or method is not in
 533     // the interesting class
 534     return NULL;
 535   }
 536   // the method is in the interesting class so the entry is interesting
 537   return m;
 538 }
 539 #endif // INCLUDE_JVMTI
 540 
 541 void ConstantPoolCacheEntry::print(outputStream* st, int index) const {
 542   // print separator
 543   if (index == 0) st->print_cr("                 -------------");
 544   // print entry
 545   st->print("%3d  ("PTR_FORMAT")  ", index, (intptr_t)this);
 546   st->print_cr("[%02x|%02x|%5d]", bytecode_2(), bytecode_1(),
 547                constant_pool_index());
 548   st->print_cr("                 [   "PTR_FORMAT"]", (intptr_t)_f1);
 549   st->print_cr("                 [   "PTR_FORMAT"]", (intptr_t)_f2);
 550   st->print_cr("                 [   "PTR_FORMAT"]", (intptr_t)_flags);
 551   st->print_cr("                 -------------");
 552 }
 553 
 554 void ConstantPoolCacheEntry::verify(outputStream* st) const {
 555   // not implemented yet
 556 }
 557 
 558 // Implementation of ConstantPoolCache
 559 
 560 ConstantPoolCache* ConstantPoolCache::allocate(ClassLoaderData* loader_data,
 561                                      const intStack& index_map,
 562                                      const intStack& invokedynamic_index_map,
 563                                      const intStack& invokedynamic_map, TRAPS) {
 564 
 565   const int length = index_map.length() + invokedynamic_index_map.length();
 566   int size = ConstantPoolCache::size(length);
 567 
 568   return new (loader_data, size, false, MetaspaceObj::ConstantPoolCacheType, THREAD)
 569     ConstantPoolCache(length, index_map, invokedynamic_index_map, invokedynamic_map);
 570 }
 571 
 572 void ConstantPoolCache::initialize(const intArray& inverse_index_map,
 573                                    const intArray& invokedynamic_inverse_index_map,
 574                                    const intArray& invokedynamic_references_map) {
 575   for (int i = 0; i < inverse_index_map.length(); i++) {
 576     ConstantPoolCacheEntry* e = entry_at(i);
 577     int original_index = inverse_index_map[i];
 578     e->initialize_entry(original_index);
 579     assert(entry_at(i) == e, "sanity");
 580   }
 581 
 582   // Append invokedynamic entries at the end
 583   int invokedynamic_offset = inverse_index_map.length();
 584   for (int i = 0; i < invokedynamic_inverse_index_map.length(); i++) {
 585     int offset = i + invokedynamic_offset;
 586     ConstantPoolCacheEntry* e = entry_at(offset);
 587     int original_index = invokedynamic_inverse_index_map[i];
 588     e->initialize_entry(original_index);
 589     assert(entry_at(offset) == e, "sanity");
 590   }
 591 
 592   for (int ref = 0; ref < invokedynamic_references_map.length(); ref++) {
 593     const int cpci = invokedynamic_references_map[ref];
 594     if (cpci >= 0) {
 595 #ifdef ASSERT
 596       // invokedynamic and invokehandle have more entries; check if they
 597       // all point to the same constant pool cache entry.
 598       for (int entry = 1; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {
 599         const int cpci_next = invokedynamic_references_map[ref + entry];
 600         assert(cpci == cpci_next, err_msg_res("%d == %d", cpci, cpci_next));
 601       }
 602 #endif
 603       entry_at(cpci)->initialize_resolved_reference_index(ref);
 604       ref += ConstantPoolCacheEntry::_indy_resolved_references_entries - 1;  // skip extra entries
 605     }
 606   }
 607 }
 608 
 609 #if INCLUDE_JVMTI
 610 // RedefineClasses() API support:
 611 // If any entry of this ConstantPoolCache points to any of
 612 // old_methods, replace it with the corresponding new_method.
 613 void ConstantPoolCache::adjust_method_entries(Method** old_methods, Method** new_methods,
 614                                               int methods_length, bool * trace_name_printed) {
 615 
 616   if (methods_length == 0) {
 617     // nothing to do if there are no methods
 618     return;
 619   }
 620 
 621   // get shorthand for the interesting class
 622   Klass* old_holder = old_methods[0]->method_holder();
 623 
 624   for (int i = 0; i < length(); i++) {
 625     if (entry_at(i)->get_interesting_method_entry(old_holder) == NULL) {
 626       // skip uninteresting methods
 627       continue;
 628     }
 629 
 630     // The ConstantPoolCache contains entries for several different
 631     // things, but we only care about methods. In fact, we only care
 632     // about methods in the same class as the one that contains the
 633     // old_methods. At this point, we have an interesting entry.
 634 
 635     for (int j = 0; j < methods_length; j++) {
 636       Method* old_method = old_methods[j];
 637       Method* new_method = new_methods[j];
 638 
 639       if (entry_at(i)->adjust_method_entry(old_method, new_method,
 640           trace_name_printed)) {
 641         // current old_method matched this entry and we updated it so
 642         // break out and get to the next interesting entry if there one
 643         break;
 644       }
 645     }
 646   }
 647 }
 648 
 649 // If any entry of this ConstantPoolCache points to any of
 650 // old_methods, replace it with the corresponding new_method.
 651 void ConstantPoolCache::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
 652   for (int i = 0; i < length(); i++) {
 653     ConstantPoolCacheEntry* entry = entry_at(i);
 654     Method* old_method = entry->get_interesting_method_entry(holder);
 655     if (old_method == NULL || !old_method->is_old()) {
 656       continue; // skip uninteresting entries
 657     }
 658     if (old_method->is_deleted()) {
 659       // clean up entries with deleted methods
 660       entry->initialize_entry(entry->constant_pool_index());
 661       continue;
 662     }
 663     Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
 664 
 665     assert(new_method != NULL, "method_with_idnum() should not be NULL");
 666     assert(old_method != new_method, "sanity check");
 667 
 668     entry_at(i)->adjust_method_entry(old_method, new_method, trace_name_printed);
 669   }
 670 }
 671 
 672 // the constant pool cache should never contain old or obsolete methods
 673 bool ConstantPoolCache::check_no_old_or_obsolete_entries() {
 674   for (int i = 1; i < length(); i++) {
 675     if (entry_at(i)->get_interesting_method_entry(NULL) != NULL &&
 676         !entry_at(i)->check_no_old_or_obsolete_entries()) {
 677       return false;
 678     }
 679   }
 680   return true;
 681 }
 682 
 683 void ConstantPoolCache::dump_cache() {
 684   for (int i = 1; i < length(); i++) {
 685     if (entry_at(i)->get_interesting_method_entry(NULL) != NULL) {
 686       entry_at(i)->print(tty, i);
 687     }
 688   }
 689 }
 690 #endif // INCLUDE_JVMTI
 691 
 692 
 693 // Printing
 694 
 695 void ConstantPoolCache::print_on(outputStream* st) const {
 696   assert(is_constantPoolCache(), "obj must be constant pool cache");
 697   st->print_cr("%s", internal_name());
 698   // print constant pool cache entries
 699   for (int i = 0; i < length(); i++) entry_at(i)->print(st, i);
 700 }
 701 
 702 void ConstantPoolCache::print_value_on(outputStream* st) const {
 703   assert(is_constantPoolCache(), "obj must be constant pool cache");
 704   st->print("cache [%d]", length());
 705   print_address_on(st);
 706   st->print(" for ");
 707   constant_pool()->print_value_on(st);
 708 }
 709 
 710 
 711 // Verification
 712 
 713 void ConstantPoolCache::verify_on(outputStream* st) {
 714   guarantee(is_constantPoolCache(), "obj must be constant pool cache");
 715   // print constant pool cache entries
 716   for (int i = 0; i < length(); i++) entry_at(i)->verify(st);
 717 }