1 /*
   2  * Copyright (c) 1998, 2017, 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 "interpreter/interpreter.hpp"
  27 #include "interpreter/rewriter.hpp"
  28 #include "logging/log.hpp"
  29 #include "memory/metaspaceClosure.hpp"
  30 #include "memory/resourceArea.hpp"
  31 #include "memory/universe.inline.hpp"
  32 #include "oops/cpCache.hpp"
  33 #include "oops/objArrayOop.inline.hpp"
  34 #include "oops/oop.inline.hpp"
  35 #include "prims/methodHandles.hpp"
  36 #include "runtime/atomic.hpp"
  37 #include "runtime/handles.inline.hpp"
  38 #include "runtime/orderAccess.inline.hpp"
  39 #include "utilities/macros.hpp"
  40 
  41 // Implementation of ConstantPoolCacheEntry
  42 
  43 void ConstantPoolCacheEntry::initialize_entry(int index) {
  44   assert(0 < index && index < 0x10000, "sanity check");
  45   _indices = index;
  46   _f1 = NULL;
  47   _f2 = _flags = 0;
  48   assert(constant_pool_index() == index, "");
  49 }
  50 
  51 int ConstantPoolCacheEntry::make_flags(TosState state,
  52                                        int option_bits,
  53                                        int field_index_or_method_params) {
  54   assert(state < number_of_states, "Invalid state in make_flags");
  55   int f = ((int)state << tos_state_shift) | option_bits | field_index_or_method_params;
  56   // Preserve existing flag bit values
  57   // The low bits are a field offset, or else the method parameter size.
  58 #ifdef ASSERT
  59   TosState old_state = flag_state();
  60   assert(old_state == (TosState)0 || old_state == state,
  61          "inconsistent cpCache flags state");
  62 #endif
  63   return (_flags | f) ;
  64 }
  65 
  66 void ConstantPoolCacheEntry::set_bytecode_1(Bytecodes::Code code) {
  67 #ifdef ASSERT
  68   // Read once.
  69   volatile Bytecodes::Code c = bytecode_1();
  70   assert(c == 0 || c == code || code == 0, "update must be consistent");
  71 #endif
  72   // Need to flush pending stores here before bytecode is written.
  73   OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << bytecode_1_shift));
  74 }
  75 
  76 void ConstantPoolCacheEntry::set_bytecode_2(Bytecodes::Code code) {
  77 #ifdef ASSERT
  78   // Read once.
  79   volatile Bytecodes::Code c = bytecode_2();
  80   assert(c == 0 || c == code || code == 0, "update must be consistent");
  81 #endif
  82   // Need to flush pending stores here before bytecode is written.
  83   OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << bytecode_2_shift));
  84 }
  85 
  86 // Sets f1, ordering with previous writes.
  87 void ConstantPoolCacheEntry::release_set_f1(Metadata* f1) {
  88   assert(f1 != NULL, "");
  89   OrderAccess::release_store_ptr((HeapWord*) &_f1, f1);
  90 }
  91 
  92 // Sets flags, but only if the value was previously zero.
  93 bool ConstantPoolCacheEntry::init_flags_atomic(intptr_t flags) {
  94   intptr_t result = Atomic::cmpxchg_ptr(flags, &_flags, 0);
  95   return (result == 0);
  96 }
  97 
  98 // Note that concurrent update of both bytecodes can leave one of them
  99 // reset to zero.  This is harmless; the interpreter will simply re-resolve
 100 // the damaged entry.  More seriously, the memory synchronization is needed
 101 // to flush other fields (f1, f2) completely to memory before the bytecodes
 102 // are updated, lest other processors see a non-zero bytecode but zero f1/f2.
 103 void ConstantPoolCacheEntry::set_field(Bytecodes::Code get_code,
 104                                        Bytecodes::Code put_code,
 105                                        Klass* field_holder,
 106                                        int field_index,
 107                                        int field_offset,
 108                                        TosState field_type,
 109                                        bool is_final,
 110                                        bool is_volatile,
 111                                        bool is_flatten,
 112                                        Klass* root_klass) {
 113   set_f1(field_holder);
 114   set_f2(field_offset);
 115   assert((field_index & field_index_mask) == field_index,
 116          "field index does not fit in low flag bits");
 117   set_field_flags(field_type,
 118                   ((is_volatile ? 1 : 0) << is_volatile_shift) |
 119                   ((is_final    ? 1 : 0) << is_final_shift) |
 120                   ((is_flatten  ? 1 : 0) << is_flatten_field),
 121                   field_index);
 122   set_bytecode_1(get_code);
 123   set_bytecode_2(put_code);
 124   NOT_PRODUCT(verify(tty));
 125 }
 126 
 127 void ConstantPoolCacheEntry::set_parameter_size(int value) {
 128   // This routine is called only in corner cases where the CPCE is not yet initialized.
 129   // See AbstractInterpreter::deopt_continue_after_entry.
 130   assert(_flags == 0 || parameter_size() == 0 || parameter_size() == value,
 131          "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
 132   // Setting the parameter size by itself is only safe if the
 133   // current value of _flags is 0, otherwise another thread may have
 134   // updated it and we don't want to overwrite that value.  Don't
 135   // bother trying to update it once it's nonzero but always make
 136   // sure that the final parameter size agrees with what was passed.
 137   if (_flags == 0) {
 138     Atomic::cmpxchg_ptr((value & parameter_size_mask), &_flags, 0);
 139   }
 140   guarantee(parameter_size() == value,
 141             "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
 142 }
 143 
 144 void ConstantPoolCacheEntry::set_direct_or_vtable_call(Bytecodes::Code invoke_code,
 145                                                        const methodHandle& method,
 146                                                        int vtable_index,
 147                                                        bool sender_is_interface) {
 148   bool is_vtable_call = (vtable_index >= 0);  // FIXME: split this method on this boolean
 149   assert(method->interpreter_entry() != NULL, "should have been set at this point");
 150   assert(!method->is_obsolete(),  "attempt to write obsolete method to cpCache");
 151 
 152   int byte_no = -1;
 153   bool change_to_virtual = false;
 154 
 155   switch (invoke_code) {
 156     case Bytecodes::_invokeinterface:
 157       // We get here from InterpreterRuntime::resolve_invoke when an invokeinterface
 158       // instruction somehow links to a non-interface method (in Object).
 159       // In that case, the method has no itable index and must be invoked as a virtual.
 160       // Set a flag to keep track of this corner case.
 161       change_to_virtual = true;
 162 
 163       // ...and fall through as if we were handling invokevirtual:
 164     case Bytecodes::_invokevirtual:
 165       {
 166         if (!is_vtable_call) {
 167           assert(method->can_be_statically_bound(), "");
 168           // set_f2_as_vfinal_method checks if is_vfinal flag is true.
 169           set_method_flags(as_TosState(method->result_type()),
 170                            (                             1      << is_vfinal_shift) |
 171                            ((method->is_final_method() ? 1 : 0) << is_final_shift)  |
 172                            ((change_to_virtual         ? 1 : 0) << is_forced_virtual_shift),
 173                            method()->size_of_parameters());
 174           set_f2_as_vfinal_method(method());
 175         } else {
 176           assert(!method->can_be_statically_bound(), "");
 177           assert(vtable_index >= 0, "valid index");
 178           assert(!method->is_final_method(), "sanity");
 179           set_method_flags(as_TosState(method->result_type()),
 180                            ((change_to_virtual ? 1 : 0) << is_forced_virtual_shift),
 181                            method()->size_of_parameters());
 182           set_f2(vtable_index);
 183         }
 184         byte_no = 2;
 185         break;
 186       }
 187 
 188     case Bytecodes::_invokespecial:
 189     case Bytecodes::_invokestatic:
 190       assert(!is_vtable_call, "");
 191       // Note:  Read and preserve the value of the is_vfinal flag on any
 192       // invokevirtual bytecode shared with this constant pool cache entry.
 193       // It is cheap and safe to consult is_vfinal() at all times.
 194       // Once is_vfinal is set, it must stay that way, lest we get a dangling oop.
 195       set_method_flags(as_TosState(method->result_type()),
 196                        ((is_vfinal()               ? 1 : 0) << is_vfinal_shift) |
 197                        ((method->is_final_method() ? 1 : 0) << is_final_shift),
 198                        method()->size_of_parameters());
 199       set_f1(method());
 200       byte_no = 1;
 201       break;
 202     default:
 203       ShouldNotReachHere();
 204       break;
 205   }
 206 
 207   // Note:  byte_no also appears in TemplateTable::resolve.
 208   if (byte_no == 1) {
 209     assert(invoke_code != Bytecodes::_invokevirtual &&
 210            invoke_code != Bytecodes::_invokeinterface, "");
 211     // Don't mark invokespecial to method as resolved if sender is an interface.  The receiver
 212     // has to be checked that it is a subclass of the current class every time this bytecode
 213     // is executed.
 214     if (invoke_code != Bytecodes::_invokespecial || !sender_is_interface ||
 215         method->name() == vmSymbols::object_initializer_name()) {
 216     set_bytecode_1(invoke_code);
 217     }
 218   } else if (byte_no == 2)  {
 219     if (change_to_virtual) {
 220       assert(invoke_code == Bytecodes::_invokeinterface, "");
 221       // NOTE: THIS IS A HACK - BE VERY CAREFUL!!!
 222       //
 223       // Workaround for the case where we encounter an invokeinterface, but we
 224       // should really have an _invokevirtual since the resolved method is a
 225       // virtual method in java.lang.Object. This is a corner case in the spec
 226       // but is presumably legal. javac does not generate this code.
 227       //
 228       // We set bytecode_1() to _invokeinterface, because that is the
 229       // bytecode # used by the interpreter to see if it is resolved.
 230       // We set bytecode_2() to _invokevirtual.
 231       // See also interpreterRuntime.cpp. (8/25/2000)
 232       // Only set resolved for the invokeinterface case if method is public.
 233       // Otherwise, the method needs to be reresolved with caller for each
 234       // interface call.
 235       if (method->is_public()) set_bytecode_1(invoke_code);
 236       invoke_code = Bytecodes::_invokevirtual;
 237     } else {
 238       assert(invoke_code == Bytecodes::_invokevirtual, "");
 239     }
 240     // set up for invokevirtual, even if linking for invokeinterface also:
 241     set_bytecode_2(invoke_code);
 242   } else {
 243     ShouldNotReachHere();
 244   }
 245   NOT_PRODUCT(verify(tty));
 246 }
 247 
 248 void ConstantPoolCacheEntry::set_direct_call(Bytecodes::Code invoke_code, const methodHandle& method,
 249                                              bool sender_is_interface) {
 250   int index = Method::nonvirtual_vtable_index;
 251   // index < 0; FIXME: inline and customize set_direct_or_vtable_call
 252   set_direct_or_vtable_call(invoke_code, method, index, sender_is_interface);
 253 }
 254 
 255 void ConstantPoolCacheEntry::set_vtable_call(Bytecodes::Code invoke_code, const methodHandle& method, int index) {
 256   // either the method is a miranda or its holder should accept the given index
 257   assert(method->method_holder()->is_interface() || method->method_holder()->verify_vtable_index(index), "");
 258   // index >= 0; FIXME: inline and customize set_direct_or_vtable_call
 259   set_direct_or_vtable_call(invoke_code, method, index, false);
 260 }
 261 
 262 void ConstantPoolCacheEntry::set_itable_call(Bytecodes::Code invoke_code, const methodHandle& method, int index) {
 263   assert(method->method_holder()->verify_itable_index(index), "");
 264   assert(invoke_code == Bytecodes::_invokeinterface, "");
 265   InstanceKlass* interf = method->method_holder();
 266   assert(interf->is_interface(), "must be an interface");
 267   assert(!method->is_final_method(), "interfaces do not have final methods; cannot link to one here");
 268   set_f1(interf);
 269   set_f2(index);
 270   set_method_flags(as_TosState(method->result_type()),
 271                    0,  // no option bits
 272                    method()->size_of_parameters());
 273   set_bytecode_1(Bytecodes::_invokeinterface);
 274 }
 275 
 276 
 277 void ConstantPoolCacheEntry::set_method_handle(const constantPoolHandle& cpool, const CallInfo &call_info) {
 278   set_method_handle_common(cpool, Bytecodes::_invokehandle, call_info);
 279 }
 280 
 281 void ConstantPoolCacheEntry::set_dynamic_call(const constantPoolHandle& cpool, const CallInfo &call_info) {
 282   set_method_handle_common(cpool, Bytecodes::_invokedynamic, call_info);
 283 }
 284 
 285 void ConstantPoolCacheEntry::set_method_handle_common(const constantPoolHandle& cpool,
 286                                                       Bytecodes::Code invoke_code,
 287                                                       const CallInfo &call_info) {
 288   // NOTE: This CPCE can be the subject of data races.
 289   // There are three words to update: flags, refs[f2], f1 (in that order).
 290   // Writers must store all other values before f1.
 291   // Readers must test f1 first for non-null before reading other fields.
 292   // Competing writers must acquire exclusive access via a lock.
 293   // A losing writer waits on the lock until the winner writes f1 and leaves
 294   // the lock, so that when the losing writer returns, he can use the linked
 295   // cache entry.
 296 
 297   objArrayHandle resolved_references(Thread::current(), cpool->resolved_references());
 298   // Use the resolved_references() lock for this cpCache entry.
 299   // resolved_references are created for all classes with Invokedynamic, MethodHandle
 300   // or MethodType constant pool cache entries.
 301   assert(resolved_references() != NULL,
 302          "a resolved_references array should have been created for this class");
 303   ObjectLocker ol(resolved_references, Thread::current());
 304   if (!is_f1_null()) {
 305     return;
 306   }
 307 
 308   const methodHandle adapter = call_info.resolved_method();
 309   const Handle appendix      = call_info.resolved_appendix();
 310   const Handle method_type   = call_info.resolved_method_type();
 311   const bool has_appendix    = appendix.not_null();
 312   const bool has_method_type = method_type.not_null();
 313 
 314   // Write the flags.
 315   set_method_flags(as_TosState(adapter->result_type()),
 316                    ((has_appendix    ? 1 : 0) << has_appendix_shift   ) |
 317                    ((has_method_type ? 1 : 0) << has_method_type_shift) |
 318                    (                   1      << is_final_shift       ),
 319                    adapter->size_of_parameters());
 320 
 321   if (TraceInvokeDynamic) {
 322     ttyLocker ttyl;
 323     tty->print_cr("set_method_handle bc=%d appendix=" PTR_FORMAT "%s method_type=" PTR_FORMAT "%s method=" PTR_FORMAT " ",
 324                   invoke_code,
 325                   p2i(appendix()),    (has_appendix    ? "" : " (unused)"),
 326                   p2i(method_type()), (has_method_type ? "" : " (unused)"),
 327                   p2i(adapter()));
 328     adapter->print();
 329     if (has_appendix)  appendix()->print();
 330   }
 331 
 332   // Method handle invokes and invokedynamic sites use both cp cache words.
 333   // refs[f2], if not null, contains a value passed as a trailing argument to the adapter.
 334   // In the general case, this could be the call site's MethodType,
 335   // for use with java.lang.Invokers.checkExactType, or else a CallSite object.
 336   // f1 contains the adapter method which manages the actual call.
 337   // In the general case, this is a compiled LambdaForm.
 338   // (The Java code is free to optimize these calls by binding other
 339   // sorts of methods and appendices to call sites.)
 340   // JVM-level linking is via f1, as if for invokespecial, and signatures are erased.
 341   // The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.
 342   // Even with the appendix, the method will never take more than 255 parameter slots.
 343   //
 344   // This means that given a call site like (List)mh.invoke("foo"),
 345   // the f1 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',
 346   // not '(Ljava/lang/String;)Ljava/util/List;'.
 347   // The fact that String and List are involved is encoded in the MethodType in refs[f2].
 348   // This allows us to create fewer Methods, while keeping type safety.
 349   //
 350 
 351   // Store appendix, if any.
 352   if (has_appendix) {
 353     const int appendix_index = f2_as_index() + _indy_resolved_references_appendix_offset;
 354     assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");
 355     assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
 356     resolved_references->obj_at_put(appendix_index, appendix());
 357   }
 358 
 359   // Store MethodType, if any.
 360   if (has_method_type) {
 361     const int method_type_index = f2_as_index() + _indy_resolved_references_method_type_offset;
 362     assert(method_type_index >= 0 && method_type_index < resolved_references->length(), "oob");
 363     assert(resolved_references->obj_at(method_type_index) == NULL, "init just once");
 364     resolved_references->obj_at_put(method_type_index, method_type());
 365   }
 366 
 367   release_set_f1(adapter());  // This must be the last one to set (see NOTE above)!
 368 
 369   // The interpreter assembly code does not check byte_2,
 370   // but it is used by is_resolved, method_if_resolved, etc.
 371   set_bytecode_1(invoke_code);
 372   NOT_PRODUCT(verify(tty));
 373   if (TraceInvokeDynamic) {
 374     ttyLocker ttyl;
 375     this->print(tty, 0);
 376   }
 377 }
 378 
 379 Method* ConstantPoolCacheEntry::method_if_resolved(const constantPoolHandle& cpool) {
 380   // Decode the action of set_method and set_interface_call
 381   Bytecodes::Code invoke_code = bytecode_1();
 382   if (invoke_code != (Bytecodes::Code)0) {
 383     Metadata* f1 = f1_ord();
 384     if (f1 != NULL) {
 385       switch (invoke_code) {
 386       case Bytecodes::_invokeinterface:
 387         assert(f1->is_klass(), "");
 388         return klassItable::method_for_itable_index((Klass*)f1, f2_as_index());
 389       case Bytecodes::_invokestatic:
 390       case Bytecodes::_invokespecial:
 391         assert(!has_appendix(), "");
 392       case Bytecodes::_invokehandle:
 393       case Bytecodes::_invokedynamic:
 394         assert(f1->is_method(), "");
 395         return (Method*)f1;
 396       default:
 397         break;
 398       }
 399     }
 400   }
 401   invoke_code = bytecode_2();
 402   if (invoke_code != (Bytecodes::Code)0) {
 403     switch (invoke_code) {
 404     case Bytecodes::_invokevirtual:
 405       if (is_vfinal()) {
 406         // invokevirtual
 407         Method* m = f2_as_vfinal_method();
 408         assert(m->is_method(), "");
 409         return m;
 410       } else {
 411         int holder_index = cpool->uncached_klass_ref_index_at(constant_pool_index());
 412         if (cpool->tag_at(holder_index).is_klass()) {
 413           Klass* klass = cpool->resolved_klass_at(holder_index);
 414           return klass->method_at_vtable(f2_as_index());
 415         }
 416       }
 417       break;
 418     default:
 419       break;
 420     }
 421   }
 422   return NULL;
 423 }
 424 
 425 
 426 oop ConstantPoolCacheEntry::appendix_if_resolved(const constantPoolHandle& cpool) {
 427   if (!has_appendix())
 428     return NULL;
 429   const int ref_index = f2_as_index() + _indy_resolved_references_appendix_offset;
 430   objArrayOop resolved_references = cpool->resolved_references();
 431   return resolved_references->obj_at(ref_index);
 432 }
 433 
 434 
 435 oop ConstantPoolCacheEntry::method_type_if_resolved(const constantPoolHandle& cpool) {
 436   if (!has_method_type())
 437     return NULL;
 438   const int ref_index = f2_as_index() + _indy_resolved_references_method_type_offset;
 439   objArrayOop resolved_references = cpool->resolved_references();
 440   return resolved_references->obj_at(ref_index);
 441 }
 442 
 443 
 444 #if INCLUDE_JVMTI
 445 // RedefineClasses() API support:
 446 // If this ConstantPoolCacheEntry refers to old_method then update it
 447 // to refer to new_method.
 448 bool ConstantPoolCacheEntry::adjust_method_entry(Method* old_method,
 449        Method* new_method, bool * trace_name_printed) {
 450 
 451   if (is_vfinal()) {
 452     // virtual and final so _f2 contains method ptr instead of vtable index
 453     if (f2_as_vfinal_method() == old_method) {
 454       // match old_method so need an update
 455       // NOTE: can't use set_f2_as_vfinal_method as it asserts on different values
 456       _f2 = (intptr_t)new_method;
 457       if (log_is_enabled(Info, redefine, class, update)) {
 458         ResourceMark rm;
 459         if (!(*trace_name_printed)) {
 460           log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
 461           *trace_name_printed = true;
 462         }
 463         log_debug(redefine, class, update, constantpool)
 464           ("cpc vf-entry update: %s(%s)", new_method->name()->as_C_string(), new_method->signature()->as_C_string());
 465       }
 466       return true;
 467     }
 468 
 469     // f1() is not used with virtual entries so bail out
 470     return false;
 471   }
 472 
 473   if (_f1 == NULL) {
 474     // NULL f1() means this is a virtual entry so bail out
 475     // We are assuming that the vtable index does not need change.
 476     return false;
 477   }
 478 
 479   if (_f1 == old_method) {
 480     _f1 = new_method;
 481     if (log_is_enabled(Info, redefine, class, update)) {
 482       ResourceMark rm;
 483       if (!(*trace_name_printed)) {
 484         log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
 485         *trace_name_printed = true;
 486       }
 487       log_debug(redefine, class, update, constantpool)
 488         ("cpc entry update: %s(%s)", new_method->name()->as_C_string(), new_method->signature()->as_C_string());
 489     }
 490     return true;
 491   }
 492 
 493   return false;
 494 }
 495 
 496 // a constant pool cache entry should never contain old or obsolete methods
 497 bool ConstantPoolCacheEntry::check_no_old_or_obsolete_entries() {
 498   if (is_vfinal()) {
 499     // virtual and final so _f2 contains method ptr instead of vtable index
 500     Metadata* f2 = (Metadata*)_f2;
 501     // Return false if _f2 refers to an old or an obsolete method.
 502     // _f2 == NULL || !_f2->is_method() are just as unexpected here.
 503     return (f2 != NULL NOT_PRODUCT(&& f2->is_valid()) && f2->is_method() &&
 504             !((Method*)f2)->is_old() && !((Method*)f2)->is_obsolete());
 505   } else if (_f1 == NULL ||
 506              (NOT_PRODUCT(_f1->is_valid() &&) !_f1->is_method())) {
 507     // _f1 == NULL || !_f1->is_method() are OK here
 508     return true;
 509   }
 510   // return false if _f1 refers to a non-deleted old or obsolete method
 511   return (NOT_PRODUCT(_f1->is_valid() &&) _f1->is_method() &&
 512           (f1_as_method()->is_deleted() ||
 513           (!f1_as_method()->is_old() && !f1_as_method()->is_obsolete())));
 514 }
 515 
 516 Method* ConstantPoolCacheEntry::get_interesting_method_entry(Klass* k) {
 517   if (!is_method_entry()) {
 518     // not a method entry so not interesting by default
 519     return NULL;
 520   }
 521   Method* m = NULL;
 522   if (is_vfinal()) {
 523     // virtual and final so _f2 contains method ptr instead of vtable index
 524     m = f2_as_vfinal_method();
 525   } else if (is_f1_null()) {
 526     // NULL _f1 means this is a virtual entry so also not interesting
 527     return NULL;
 528   } else {
 529     if (!(_f1->is_method())) {
 530       // _f1 can also contain a Klass* for an interface
 531       return NULL;
 532     }
 533     m = f1_as_method();
 534   }
 535   assert(m != NULL && m->is_method(), "sanity check");
 536   if (m == NULL || !m->is_method() || (k != NULL && m->method_holder() != k)) {
 537     // robustness for above sanity checks or method is not in
 538     // the interesting class
 539     return NULL;
 540   }
 541   // the method is in the interesting class so the entry is interesting
 542   return m;
 543 }
 544 #endif // INCLUDE_JVMTI
 545 
 546 void ConstantPoolCacheEntry::print(outputStream* st, int index) const {
 547   // print separator
 548   if (index == 0) st->print_cr("                 -------------");
 549   // print entry
 550   st->print("%3d  (" PTR_FORMAT ")  ", index, (intptr_t)this);
 551   st->print_cr("[%02x|%02x|%5d]", bytecode_2(), bytecode_1(),
 552                constant_pool_index());
 553   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f1);
 554   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f2);
 555   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_flags);
 556   st->print_cr("                 -------------");
 557 }
 558 
 559 void ConstantPoolCacheEntry::verify(outputStream* st) const {
 560   // not implemented yet
 561 }
 562 
 563 // Implementation of ConstantPoolCache
 564 
 565 ConstantPoolCache* ConstantPoolCache::allocate(ClassLoaderData* loader_data,
 566                                      const intStack& index_map,
 567                                      const intStack& invokedynamic_index_map,
 568                                      const intStack& invokedynamic_map, TRAPS) {
 569 
 570   const int length = index_map.length() + invokedynamic_index_map.length();
 571   int size = ConstantPoolCache::size(length);
 572 
 573   return new (loader_data, size, MetaspaceObj::ConstantPoolCacheType, THREAD)
 574     ConstantPoolCache(length, index_map, invokedynamic_index_map, invokedynamic_map);
 575 }
 576 
 577 void ConstantPoolCache::initialize(const intArray& inverse_index_map,
 578                                    const intArray& invokedynamic_inverse_index_map,
 579                                    const intArray& invokedynamic_references_map) {
 580   for (int i = 0; i < inverse_index_map.length(); i++) {
 581     ConstantPoolCacheEntry* e = entry_at(i);
 582     int original_index = inverse_index_map.at(i);
 583     e->initialize_entry(original_index);
 584     assert(entry_at(i) == e, "sanity");
 585   }
 586 
 587   // Append invokedynamic entries at the end
 588   int invokedynamic_offset = inverse_index_map.length();
 589   for (int i = 0; i < invokedynamic_inverse_index_map.length(); i++) {
 590     int offset = i + invokedynamic_offset;
 591     ConstantPoolCacheEntry* e = entry_at(offset);
 592     int original_index = invokedynamic_inverse_index_map.at(i);
 593     e->initialize_entry(original_index);
 594     assert(entry_at(offset) == e, "sanity");
 595   }
 596 
 597   for (int ref = 0; ref < invokedynamic_references_map.length(); ref++) {
 598     const int cpci = invokedynamic_references_map.at(ref);
 599     if (cpci >= 0) {
 600 #ifdef ASSERT
 601       // invokedynamic and invokehandle have more entries; check if they
 602       // all point to the same constant pool cache entry.
 603       for (int entry = 1; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {
 604         const int cpci_next = invokedynamic_references_map.at(ref + entry);
 605         assert(cpci == cpci_next, "%d == %d", cpci, cpci_next);
 606       }
 607 #endif
 608       entry_at(cpci)->initialize_resolved_reference_index(ref);
 609       ref += ConstantPoolCacheEntry::_indy_resolved_references_entries - 1;  // skip extra entries
 610     }
 611   }
 612 }
 613 
 614 #if INCLUDE_CDS_JAVA_HEAP
 615 oop ConstantPoolCache::archived_references() {
 616   assert(UseSharedSpaces, "UseSharedSpaces expected.");
 617   return oopDesc::decode_heap_oop(_archived_references);
 618 }
 619 
 620 void ConstantPoolCache::set_archived_references(oop o) {
 621   assert(DumpSharedSpaces, "called only during runtime");
 622   _archived_references = oopDesc::encode_heap_oop(o);
 623 }
 624 #endif
 625 
 626 #if INCLUDE_JVMTI
 627 // RedefineClasses() API support:
 628 // If any entry of this ConstantPoolCache points to any of
 629 // old_methods, replace it with the corresponding new_method.
 630 void ConstantPoolCache::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
 631   for (int i = 0; i < length(); i++) {
 632     ConstantPoolCacheEntry* entry = entry_at(i);
 633     Method* old_method = entry->get_interesting_method_entry(holder);
 634     if (old_method == NULL || !old_method->is_old()) {
 635       continue; // skip uninteresting entries
 636     }
 637     if (old_method->is_deleted()) {
 638       // clean up entries with deleted methods
 639       entry->initialize_entry(entry->constant_pool_index());
 640       continue;
 641     }
 642     Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
 643 
 644     assert(new_method != NULL, "method_with_idnum() should not be NULL");
 645     assert(old_method != new_method, "sanity check");
 646 
 647     entry_at(i)->adjust_method_entry(old_method, new_method, trace_name_printed);
 648   }
 649 }
 650 
 651 // the constant pool cache should never contain old or obsolete methods
 652 bool ConstantPoolCache::check_no_old_or_obsolete_entries() {
 653   for (int i = 1; i < length(); i++) {
 654     if (entry_at(i)->get_interesting_method_entry(NULL) != NULL &&
 655         !entry_at(i)->check_no_old_or_obsolete_entries()) {
 656       return false;
 657     }
 658   }
 659   return true;
 660 }
 661 
 662 void ConstantPoolCache::dump_cache() {
 663   for (int i = 1; i < length(); i++) {
 664     if (entry_at(i)->get_interesting_method_entry(NULL) != NULL) {
 665       entry_at(i)->print(tty, i);
 666     }
 667   }
 668 }
 669 #endif // INCLUDE_JVMTI
 670 
 671 void ConstantPoolCache::metaspace_pointers_do(MetaspaceClosure* it) {
 672   log_trace(cds)("Iter(ConstantPoolCache): %p", this);
 673   it->push(&_constant_pool);
 674   it->push(&_reference_map);
 675 }
 676 
 677 // Printing
 678 
 679 void ConstantPoolCache::print_on(outputStream* st) const {
 680   assert(is_constantPoolCache(), "obj must be constant pool cache");
 681   st->print_cr("%s", internal_name());
 682   // print constant pool cache entries
 683   for (int i = 0; i < length(); i++) entry_at(i)->print(st, i);
 684 }
 685 
 686 void ConstantPoolCache::print_value_on(outputStream* st) const {
 687   assert(is_constantPoolCache(), "obj must be constant pool cache");
 688   st->print("cache [%d]", length());
 689   print_address_on(st);
 690   st->print(" for ");
 691   constant_pool()->print_value_on(st);
 692 }
 693 
 694 
 695 // Verification
 696 
 697 void ConstantPoolCache::verify_on(outputStream* st) {
 698   guarantee(is_constantPoolCache(), "obj must be constant pool cache");
 699   // print constant pool cache entries
 700   for (int i = 0; i < length(); i++) entry_at(i)->verify(st);
 701 }