1 /*
   2  * Copyright (c) 1998, 2018, 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 "classfile/resolutionErrors.hpp"
  27 #include "interpreter/bytecodeStream.hpp"
  28 #include "interpreter/bytecodes.hpp"
  29 #include "interpreter/interpreter.hpp"
  30 #include "interpreter/linkResolver.hpp"
  31 #include "interpreter/rewriter.hpp"
  32 #include "logging/log.hpp"
  33 #include "memory/metadataFactory.hpp"
  34 #include "memory/metaspaceClosure.hpp"
  35 #include "memory/metaspaceShared.hpp"
  36 #include "memory/resourceArea.hpp"
  37 #include "memory/universe.hpp"
  38 #include "oops/access.inline.hpp"
  39 #include "oops/constantPool.inline.hpp"
  40 #include "oops/cpCache.inline.hpp"
  41 #include "oops/objArrayOop.inline.hpp"
  42 #include "oops/oop.inline.hpp"
  43 #include "prims/methodHandles.hpp"
  44 #include "runtime/atomic.hpp"
  45 #include "runtime/handles.inline.hpp"
  46 #include "runtime/orderAccess.hpp"
  47 #include "utilities/macros.hpp"
  48 
  49 // Implementation of ConstantPoolCacheEntry
  50 
  51 void ConstantPoolCacheEntry::initialize_entry(int index) {
  52   assert(0 < index && index < 0x10000, "sanity check");
  53   _indices = index;
  54   _f1 = NULL;
  55   _f2 = _flags = 0;
  56   assert(constant_pool_index() == index, "");
  57 }
  58 
  59 void ConstantPoolCacheEntry::verify_just_initialized(bool f2_used) {
  60   assert((_indices & (~cp_index_mask)) == 0, "sanity");
  61   assert(_f1 == NULL, "sanity");
  62   assert(_flags == 0, "sanity");
  63   if (!f2_used) {
  64     assert(_f2 == 0, "sanity");
  65   }
  66 }
  67 
  68 void ConstantPoolCacheEntry::reinitialize(bool f2_used) {
  69   _indices &= cp_index_mask;
  70   _f1 = NULL;
  71   _flags = 0;
  72   if (!f2_used) {
  73     _f2 = 0;
  74   }
  75 }
  76 
  77 int ConstantPoolCacheEntry::make_flags(TosState state,
  78                                        int option_bits,
  79                                        int field_index_or_method_params) {
  80   assert(state < number_of_states, "Invalid state in make_flags");
  81   int f = ((int)state << tos_state_shift) | option_bits | field_index_or_method_params;
  82   // Preserve existing flag bit values
  83   // The low bits are a field offset, or else the method parameter size.
  84 #ifdef ASSERT
  85   TosState old_state = flag_state();
  86   assert(old_state == (TosState)0 || old_state == state,
  87          "inconsistent cpCache flags state");
  88 #endif
  89   return (_flags | f) ;
  90 }
  91 
  92 void ConstantPoolCacheEntry::set_bytecode_1(Bytecodes::Code code) {
  93 #ifdef ASSERT
  94   // Read once.
  95   volatile Bytecodes::Code c = bytecode_1();
  96   assert(c == 0 || c == code || code == 0, "update must be consistent");
  97 #endif
  98   // Need to flush pending stores here before bytecode is written.
  99   OrderAccess::release_store(&_indices, _indices | ((u_char)code << bytecode_1_shift));
 100 }
 101 
 102 void ConstantPoolCacheEntry::set_bytecode_2(Bytecodes::Code code) {
 103 #ifdef ASSERT
 104   // Read once.
 105   volatile Bytecodes::Code c = bytecode_2();
 106   assert(c == 0 || c == code || code == 0, "update must be consistent");
 107 #endif
 108   // Need to flush pending stores here before bytecode is written.
 109   OrderAccess::release_store(&_indices, _indices | ((u_char)code << bytecode_2_shift));
 110 }
 111 
 112 // Sets f1, ordering with previous writes.
 113 void ConstantPoolCacheEntry::release_set_f1(Metadata* f1) {
 114   assert(f1 != NULL, "");
 115   OrderAccess::release_store(&_f1, f1);
 116 }
 117 
 118 void ConstantPoolCacheEntry::set_indy_resolution_failed() {
 119   OrderAccess::release_store(&_flags, _flags | (1 << indy_resolution_failed_shift));
 120 }
 121 
 122 // Note that concurrent update of both bytecodes can leave one of them
 123 // reset to zero.  This is harmless; the interpreter will simply re-resolve
 124 // the damaged entry.  More seriously, the memory synchronization is needed
 125 // to flush other fields (f1, f2) completely to memory before the bytecodes
 126 // are updated, lest other processors see a non-zero bytecode but zero f1/f2.
 127 void ConstantPoolCacheEntry::set_field(Bytecodes::Code get_code,
 128                                        Bytecodes::Code put_code,
 129                                        Klass* field_holder,
 130                                        int field_index,
 131                                        int field_offset,
 132                                        TosState field_type,
 133                                        bool is_final,
 134                                        bool is_volatile,
 135                                        Klass* root_klass) {
 136   set_f1(field_holder);
 137   set_f2(field_offset);
 138   assert((field_index & field_index_mask) == field_index,
 139          "field index does not fit in low flag bits");
 140   set_field_flags(field_type,
 141                   ((is_volatile ? 1 : 0) << is_volatile_shift) |
 142                   ((is_final    ? 1 : 0) << is_final_shift),
 143                   field_index);
 144   set_bytecode_1(get_code);
 145   set_bytecode_2(put_code);
 146   NOT_PRODUCT(verify(tty));
 147 }
 148 
 149 void ConstantPoolCacheEntry::set_parameter_size(int value) {
 150   // This routine is called only in corner cases where the CPCE is not yet initialized.
 151   // See AbstractInterpreter::deopt_continue_after_entry.
 152   assert(_flags == 0 || parameter_size() == 0 || parameter_size() == value,
 153          "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
 154   // Setting the parameter size by itself is only safe if the
 155   // current value of _flags is 0, otherwise another thread may have
 156   // updated it and we don't want to overwrite that value.  Don't
 157   // bother trying to update it once it's nonzero but always make
 158   // sure that the final parameter size agrees with what was passed.
 159   if (_flags == 0) {
 160     intx newflags = (value & parameter_size_mask);
 161     Atomic::cmpxchg(newflags, &_flags, (intx)0);
 162   }
 163   guarantee(parameter_size() == value,
 164             "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
 165 }
 166 
 167 void ConstantPoolCacheEntry::set_direct_or_vtable_call(Bytecodes::Code invoke_code,
 168                                                        const methodHandle& method,
 169                                                        int vtable_index,
 170                                                        bool sender_is_interface) {
 171   bool is_vtable_call = (vtable_index >= 0);  // FIXME: split this method on this boolean
 172   assert(method->interpreter_entry() != NULL, "should have been set at this point");
 173   assert(!method->is_obsolete(),  "attempt to write obsolete method to cpCache");
 174 
 175   int byte_no = -1;
 176   bool change_to_virtual = false;
 177   InstanceKlass* holder = NULL;  // have to declare this outside the switch
 178   switch (invoke_code) {
 179     case Bytecodes::_invokeinterface:
 180       holder = method->method_holder();
 181       // check for private interface method invocations
 182       if (vtable_index == Method::nonvirtual_vtable_index && holder->is_interface() ) {
 183         assert(method->is_private(), "unexpected non-private method");
 184         assert(method->can_be_statically_bound(), "unexpected non-statically-bound method");
 185         // set_f2_as_vfinal_method checks if is_vfinal flag is true.
 186         set_method_flags(as_TosState(method->result_type()),
 187                          (                             1      << is_vfinal_shift) |
 188                          ((method->is_final_method() ? 1 : 0) << is_final_shift),
 189                          method()->size_of_parameters());
 190         set_f2_as_vfinal_method(method());
 191         byte_no = 2;
 192         set_f1(holder); // interface klass*
 193         break;
 194       }
 195       else {
 196         // We get here from InterpreterRuntime::resolve_invoke when an invokeinterface
 197         // instruction links to a non-interface method (in Object). This can happen when
 198         // an interface redeclares an Object method (like CharSequence declaring toString())
 199         // or when invokeinterface is used explicitly.
 200         // In that case, the method has no itable index and must be invoked as a virtual.
 201         // Set a flag to keep track of this corner case.
 202         assert(holder->is_interface() || holder == SystemDictionary::Object_klass(), "unexpected holder class");
 203         assert(method->is_public(), "Calling non-public method in Object with invokeinterface");
 204         change_to_virtual = true;
 205 
 206         // ...and fall through as if we were handling invokevirtual:
 207       }
 208     case Bytecodes::_invokevirtual:
 209       {
 210         if (!is_vtable_call) {
 211           assert(method->can_be_statically_bound(), "");
 212           // set_f2_as_vfinal_method checks if is_vfinal flag is true.
 213           set_method_flags(as_TosState(method->result_type()),
 214                            (                             1      << is_vfinal_shift) |
 215                            ((method->is_final_method() ? 1 : 0) << is_final_shift)  |
 216                            ((change_to_virtual         ? 1 : 0) << is_forced_virtual_shift),
 217                            method()->size_of_parameters());
 218           set_f2_as_vfinal_method(method());
 219         } else {
 220           assert(!method->can_be_statically_bound(), "");
 221           assert(vtable_index >= 0, "valid index");
 222           assert(!method->is_final_method(), "sanity");
 223           set_method_flags(as_TosState(method->result_type()),
 224                            ((change_to_virtual ? 1 : 0) << is_forced_virtual_shift),
 225                            method()->size_of_parameters());
 226           set_f2(vtable_index);
 227         }
 228         byte_no = 2;
 229         break;
 230       }
 231 
 232     case Bytecodes::_invokespecial:
 233     case Bytecodes::_invokestatic:
 234       assert(!is_vtable_call, "");
 235       // Note:  Read and preserve the value of the is_vfinal flag on any
 236       // invokevirtual bytecode shared with this constant pool cache entry.
 237       // It is cheap and safe to consult is_vfinal() at all times.
 238       // Once is_vfinal is set, it must stay that way, lest we get a dangling oop.
 239       set_method_flags(as_TosState(method->result_type()),
 240                        ((is_vfinal()               ? 1 : 0) << is_vfinal_shift) |
 241                        ((method->is_final_method() ? 1 : 0) << is_final_shift),
 242                        method()->size_of_parameters());
 243       set_f1(method());
 244       byte_no = 1;
 245       break;
 246     default:
 247       ShouldNotReachHere();
 248       break;
 249   }
 250 
 251   // Note:  byte_no also appears in TemplateTable::resolve.
 252   if (byte_no == 1) {
 253     assert(invoke_code != Bytecodes::_invokevirtual &&
 254            invoke_code != Bytecodes::_invokeinterface, "");
 255     // Don't mark invokespecial to method as resolved if sender is an interface.  The receiver
 256     // has to be checked that it is a subclass of the current class every time this bytecode
 257     // is executed.
 258     if (invoke_code != Bytecodes::_invokespecial || !sender_is_interface ||
 259         method->name() == vmSymbols::object_initializer_name()) {
 260       set_bytecode_1(invoke_code);
 261     }
 262   } else if (byte_no == 2)  {
 263     if (change_to_virtual) {
 264       assert(invoke_code == Bytecodes::_invokeinterface, "");
 265       // NOTE: THIS IS A HACK - BE VERY CAREFUL!!!
 266       //
 267       // Workaround for the case where we encounter an invokeinterface, but we
 268       // should really have an _invokevirtual since the resolved method is a
 269       // virtual method in java.lang.Object. This is a corner case in the spec
 270       // but is presumably legal. javac does not generate this code.
 271       //
 272       // We do not set bytecode_1() to _invokeinterface, because that is the
 273       // bytecode # used by the interpreter to see if it is resolved.  In this
 274       // case, the method gets reresolved with caller for each interface call
 275       // because the actual selected method may not be public.
 276       //
 277       // We set bytecode_2() to _invokevirtual.
 278       // See also interpreterRuntime.cpp. (8/25/2000)
 279     } else {
 280       assert(invoke_code == Bytecodes::_invokevirtual ||
 281              (invoke_code == Bytecodes::_invokeinterface &&
 282               ((method->is_private() ||
 283                 (method->is_final() && method->method_holder() == SystemDictionary::Object_klass())))),
 284              "unexpected invocation mode");
 285       if (invoke_code == Bytecodes::_invokeinterface &&
 286           (method->is_private() || method->is_final())) {
 287         // We set bytecode_1() to _invokeinterface, because that is the
 288         // bytecode # used by the interpreter to see if it is resolved.
 289         // We set bytecode_2() to _invokevirtual.
 290         set_bytecode_1(invoke_code);
 291       }
 292     }
 293     // set up for invokevirtual, even if linking for invokeinterface also:
 294     set_bytecode_2(Bytecodes::_invokevirtual);
 295   } else {
 296     ShouldNotReachHere();
 297   }
 298   NOT_PRODUCT(verify(tty));
 299 }
 300 
 301 void ConstantPoolCacheEntry::set_direct_call(Bytecodes::Code invoke_code, const methodHandle& method,
 302                                              bool sender_is_interface) {
 303   int index = Method::nonvirtual_vtable_index;
 304   // index < 0; FIXME: inline and customize set_direct_or_vtable_call
 305   set_direct_or_vtable_call(invoke_code, method, index, sender_is_interface);
 306 }
 307 
 308 void ConstantPoolCacheEntry::set_vtable_call(Bytecodes::Code invoke_code, const methodHandle& method, int index) {
 309   // either the method is a miranda or its holder should accept the given index
 310   assert(method->method_holder()->is_interface() || method->method_holder()->verify_vtable_index(index), "");
 311   // index >= 0; FIXME: inline and customize set_direct_or_vtable_call
 312   set_direct_or_vtable_call(invoke_code, method, index, false);
 313 }
 314 
 315 void ConstantPoolCacheEntry::set_itable_call(Bytecodes::Code invoke_code,
 316                                              Klass* referenced_klass,
 317                                              const methodHandle& method, int index) {
 318   assert(method->method_holder()->verify_itable_index(index), "");
 319   assert(invoke_code == Bytecodes::_invokeinterface, "");
 320   InstanceKlass* interf = method->method_holder();
 321   assert(interf->is_interface(), "must be an interface");
 322   assert(!method->is_final_method(), "interfaces do not have final methods; cannot link to one here");
 323   set_f1(referenced_klass);
 324   set_f2((intx)method());
 325   set_method_flags(as_TosState(method->result_type()),
 326                    0,  // no option bits
 327                    method()->size_of_parameters());
 328   set_bytecode_1(Bytecodes::_invokeinterface);
 329 }
 330 
 331 
 332 void ConstantPoolCacheEntry::set_method_handle(const constantPoolHandle& cpool, const CallInfo &call_info) {
 333   set_method_handle_common(cpool, Bytecodes::_invokehandle, call_info);
 334 }
 335 
 336 void ConstantPoolCacheEntry::set_dynamic_call(const constantPoolHandle& cpool, const CallInfo &call_info) {
 337   set_method_handle_common(cpool, Bytecodes::_invokedynamic, call_info);
 338 }
 339 
 340 void ConstantPoolCacheEntry::set_method_handle_common(const constantPoolHandle& cpool,
 341                                                       Bytecodes::Code invoke_code,
 342                                                       const CallInfo &call_info) {
 343   // NOTE: This CPCE can be the subject of data races.
 344   // There are three words to update: flags, refs[f2], f1 (in that order).
 345   // Writers must store all other values before f1.
 346   // Readers must test f1 first for non-null before reading other fields.
 347   // Competing writers must acquire exclusive access via a lock.
 348   // A losing writer waits on the lock until the winner writes f1 and leaves
 349   // the lock, so that when the losing writer returns, he can use the linked
 350   // cache entry.
 351 
 352   objArrayHandle resolved_references(Thread::current(), cpool->resolved_references());
 353   // Use the resolved_references() lock for this cpCache entry.
 354   // resolved_references are created for all classes with Invokedynamic, MethodHandle
 355   // or MethodType constant pool cache entries.
 356   assert(resolved_references() != NULL,
 357          "a resolved_references array should have been created for this class");
 358   ObjectLocker ol(resolved_references, Thread::current());
 359   if (!is_f1_null()) {
 360     return;
 361   }
 362 
 363   if (indy_resolution_failed()) {
 364     // Before we got here, another thread got a LinkageError exception during
 365     // resolution.  Ignore our success and throw their exception.
 366     ConstantPoolCache* cpCache = cpool->cache();
 367     int index = -1;
 368     for (int i = 0; i < cpCache->length(); i++) {
 369       if (cpCache->entry_at(i) == this) {
 370         index = i;
 371         break;
 372       }
 373     }
 374     guarantee(index >= 0, "Didn't find cpCache entry!");
 375     int encoded_index = ResolutionErrorTable::encode_cpcache_index(
 376                           ConstantPool::encode_invokedynamic_index(index));
 377     Thread* THREAD = Thread::current();
 378     ConstantPool::throw_resolution_error(cpool, encoded_index, THREAD);
 379     return;
 380   }
 381 
 382   const methodHandle adapter = call_info.resolved_method();
 383   const Handle appendix      = call_info.resolved_appendix();
 384   const Handle method_type   = call_info.resolved_method_type();
 385   const bool has_appendix    = appendix.not_null();
 386   const bool has_method_type = method_type.not_null();
 387 
 388   // Write the flags.
 389   set_method_flags(as_TosState(adapter->result_type()),
 390                    ((has_appendix    ? 1 : 0) << has_appendix_shift   ) |
 391                    ((has_method_type ? 1 : 0) << has_method_type_shift) |
 392                    (                   1      << is_final_shift       ),
 393                    adapter->size_of_parameters());
 394 
 395   if (TraceInvokeDynamic) {
 396     ttyLocker ttyl;
 397     tty->print_cr("set_method_handle bc=%d appendix=" PTR_FORMAT "%s method_type=" PTR_FORMAT "%s method=" PTR_FORMAT " ",
 398                   invoke_code,
 399                   p2i(appendix()),    (has_appendix    ? "" : " (unused)"),
 400                   p2i(method_type()), (has_method_type ? "" : " (unused)"),
 401                   p2i(adapter()));
 402     adapter->print();
 403     if (has_appendix)  appendix()->print();
 404   }
 405 
 406   // Method handle invokes and invokedynamic sites use both cp cache words.
 407   // refs[f2], if not null, contains a value passed as a trailing argument to the adapter.
 408   // In the general case, this could be the call site's MethodType,
 409   // for use with java.lang.Invokers.checkExactType, or else a CallSite object.
 410   // f1 contains the adapter method which manages the actual call.
 411   // In the general case, this is a compiled LambdaForm.
 412   // (The Java code is free to optimize these calls by binding other
 413   // sorts of methods and appendices to call sites.)
 414   // JVM-level linking is via f1, as if for invokespecial, and signatures are erased.
 415   // The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.
 416   // Even with the appendix, the method will never take more than 255 parameter slots.
 417   //
 418   // This means that given a call site like (List)mh.invoke("foo"),
 419   // the f1 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',
 420   // not '(Ljava/lang/String;)Ljava/util/List;'.
 421   // The fact that String and List are involved is encoded in the MethodType in refs[f2].
 422   // This allows us to create fewer Methods, while keeping type safety.
 423   //
 424 
 425   // Store appendix, if any.
 426   if (has_appendix) {
 427     const int appendix_index = f2_as_index() + _indy_resolved_references_appendix_offset;
 428     assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");
 429     assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
 430     resolved_references->obj_at_put(appendix_index, appendix());
 431   }
 432 
 433   // Store MethodType, if any.
 434   if (has_method_type) {
 435     const int method_type_index = f2_as_index() + _indy_resolved_references_method_type_offset;
 436     assert(method_type_index >= 0 && method_type_index < resolved_references->length(), "oob");
 437     assert(resolved_references->obj_at(method_type_index) == NULL, "init just once");
 438     resolved_references->obj_at_put(method_type_index, method_type());
 439   }
 440 
 441   release_set_f1(adapter());  // This must be the last one to set (see NOTE above)!
 442 
 443   // The interpreter assembly code does not check byte_2,
 444   // but it is used by is_resolved, method_if_resolved, etc.
 445   set_bytecode_1(invoke_code);
 446   NOT_PRODUCT(verify(tty));
 447   if (TraceInvokeDynamic) {
 448     ttyLocker ttyl;
 449     this->print(tty, 0);
 450   }
 451 }
 452 
 453 bool ConstantPoolCacheEntry::save_and_throw_indy_exc(
 454   const constantPoolHandle& cpool, int cpool_index, int index, constantTag tag, TRAPS) {
 455 
 456   assert(HAS_PENDING_EXCEPTION, "No exception got thrown!");
 457   assert(PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass()),
 458          "No LinkageError exception");
 459 
 460   // Use the resolved_references() lock for this cpCache entry.
 461   // resolved_references are created for all classes with Invokedynamic, MethodHandle
 462   // or MethodType constant pool cache entries.
 463   objArrayHandle resolved_references(Thread::current(), cpool->resolved_references());
 464   assert(resolved_references() != NULL,
 465          "a resolved_references array should have been created for this class");
 466   ObjectLocker ol(resolved_references, THREAD);
 467 
 468   // if f1 is not null or the indy_resolution_failed flag is set then another
 469   // thread either succeeded in resolving the method or got a LinkageError
 470   // exception, before this thread was able to record its failure.  So, clear
 471   // this thread's exception and return false so caller can use the earlier
 472   // thread's result.
 473   if (!is_f1_null() || indy_resolution_failed()) {
 474     CLEAR_PENDING_EXCEPTION;
 475     return false;
 476   }
 477 
 478   Symbol* error = PENDING_EXCEPTION->klass()->name();
 479   Symbol* message = java_lang_Throwable::detail_message(PENDING_EXCEPTION);
 480   assert(message != NULL, "Missing detail message");
 481 
 482   SystemDictionary::add_resolution_error(cpool, index, error, message);
 483   set_indy_resolution_failed();
 484   return true;
 485 }
 486 
 487 Method* ConstantPoolCacheEntry::method_if_resolved(const constantPoolHandle& cpool) {
 488   // Decode the action of set_method and set_interface_call
 489   Bytecodes::Code invoke_code = bytecode_1();
 490   if (invoke_code != (Bytecodes::Code)0) {
 491     Metadata* f1 = f1_ord();
 492     if (f1 != NULL) {
 493       switch (invoke_code) {
 494       case Bytecodes::_invokeinterface:
 495         assert(f1->is_klass(), "");
 496         return klassItable::method_for_itable_index((Klass*)f1, f2_as_index());
 497       case Bytecodes::_invokestatic:
 498       case Bytecodes::_invokespecial:
 499         assert(!has_appendix(), "");
 500       case Bytecodes::_invokehandle:
 501       case Bytecodes::_invokedynamic:
 502         assert(f1->is_method(), "");
 503         return (Method*)f1;
 504       default:
 505         break;
 506       }
 507     }
 508   }
 509   invoke_code = bytecode_2();
 510   if (invoke_code != (Bytecodes::Code)0) {
 511     switch (invoke_code) {
 512     case Bytecodes::_invokevirtual:
 513       if (is_vfinal()) {
 514         // invokevirtual
 515         Method* m = f2_as_vfinal_method();
 516         assert(m->is_method(), "");
 517         return m;
 518       } else {
 519         int holder_index = cpool->uncached_klass_ref_index_at(constant_pool_index());
 520         if (cpool->tag_at(holder_index).is_klass()) {
 521           Klass* klass = cpool->resolved_klass_at(holder_index);
 522           return klass->method_at_vtable(f2_as_index());
 523         }
 524       }
 525       break;
 526     default:
 527       break;
 528     }
 529   }
 530   return NULL;
 531 }
 532 
 533 
 534 oop ConstantPoolCacheEntry::appendix_if_resolved(const constantPoolHandle& cpool) {
 535   if (!has_appendix())
 536     return NULL;
 537   const int ref_index = f2_as_index() + _indy_resolved_references_appendix_offset;
 538   objArrayOop resolved_references = cpool->resolved_references();
 539   return resolved_references->obj_at(ref_index);
 540 }
 541 
 542 
 543 oop ConstantPoolCacheEntry::method_type_if_resolved(const constantPoolHandle& cpool) {
 544   if (!has_method_type())
 545     return NULL;
 546   const int ref_index = f2_as_index() + _indy_resolved_references_method_type_offset;
 547   objArrayOop resolved_references = cpool->resolved_references();
 548   return resolved_references->obj_at(ref_index);
 549 }
 550 
 551 
 552 #if INCLUDE_JVMTI
 553 
 554 void log_adjust(const char* entry_type, Method* old_method, Method* new_method, bool* trace_name_printed) {
 555   if (log_is_enabled(Info, redefine, class, update)) {
 556     ResourceMark rm;
 557     if (!(*trace_name_printed)) {
 558       log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
 559       *trace_name_printed = true;
 560     }
 561     log_debug(redefine, class, update, constantpool)
 562           ("cpc %s entry update: %s(%s)", entry_type, new_method->name()->as_C_string(), new_method->signature()->as_C_string());
 563   }
 564 }
 565 
 566 // RedefineClasses() API support:
 567 // If this ConstantPoolCacheEntry refers to old_method then update it
 568 // to refer to new_method.
 569 void ConstantPoolCacheEntry::adjust_method_entry(Method* old_method,
 570        Method* new_method, bool * trace_name_printed) {
 571 
 572   if (is_vfinal()) {
 573     // virtual and final so _f2 contains method ptr instead of vtable index
 574     if (f2_as_vfinal_method() == old_method) {
 575       // match old_method so need an update
 576       // NOTE: can't use set_f2_as_vfinal_method as it asserts on different values
 577       _f2 = (intptr_t)new_method;
 578       log_adjust("vfinal", old_method, new_method, trace_name_printed);
 579     }
 580     return;
 581   }
 582 
 583   assert (_f1 != NULL, "should not call with uninteresting entry");
 584 
 585   if (!(_f1->is_method())) {
 586     // _f1 is a Klass* for an interface, _f2 is the method
 587     if (f2_as_interface_method() == old_method) {
 588       _f2 = (intptr_t)new_method;
 589       log_adjust("interface", old_method, new_method, trace_name_printed);
 590     }
 591   } else if (_f1 == old_method) {
 592     _f1 = new_method;
 593     log_adjust("special, static or dynamic", old_method, new_method, trace_name_printed);
 594   }
 595 }
 596 
 597 // a constant pool cache entry should never contain old or obsolete methods
 598 bool ConstantPoolCacheEntry::check_no_old_or_obsolete_entries() {
 599   Method* m = get_interesting_method_entry(NULL);
 600   // return false if m refers to a non-deleted old or obsolete method
 601   if (m != NULL) {
 602     assert(m->is_valid() && m->is_method(), "m is a valid method");
 603     return !m->is_old() && !m->is_obsolete(); // old is always set for old and obsolete
 604   } else {
 605     return true;
 606   }
 607 }
 608 
 609 Method* ConstantPoolCacheEntry::get_interesting_method_entry(Klass* k) {
 610   if (!is_method_entry()) {
 611     // not a method entry so not interesting by default
 612     return NULL;
 613   }
 614   Method* m = NULL;
 615   if (is_vfinal()) {
 616     // virtual and final so _f2 contains method ptr instead of vtable index
 617     m = f2_as_vfinal_method();
 618   } else if (is_f1_null()) {
 619     // NULL _f1 means this is a virtual entry so also not interesting
 620     return NULL;
 621   } else {
 622     if (!(_f1->is_method())) {
 623       // _f1 is a Klass* for an interface
 624       m = f2_as_interface_method();
 625     } else {
 626       m = f1_as_method();
 627     }
 628   }
 629   assert(m != NULL && m->is_method(), "sanity check");
 630   if (m == NULL || !m->is_method() || (k != NULL && m->method_holder() != k)) {
 631     // robustness for above sanity checks or method is not in
 632     // the interesting class
 633     return NULL;
 634   }
 635   // the method is in the interesting class so the entry is interesting
 636   return m;
 637 }
 638 #endif // INCLUDE_JVMTI
 639 
 640 void ConstantPoolCacheEntry::print(outputStream* st, int index) const {
 641   // print separator
 642   if (index == 0) st->print_cr("                 -------------");
 643   // print entry
 644   st->print("%3d  (" PTR_FORMAT ")  ", index, (intptr_t)this);
 645   st->print_cr("[%02x|%02x|%5d]", bytecode_2(), bytecode_1(),
 646                constant_pool_index());
 647   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f1);
 648   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f2);
 649   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_flags);
 650   st->print_cr("                 -------------");
 651 }
 652 
 653 void ConstantPoolCacheEntry::verify(outputStream* st) const {
 654   // not implemented yet
 655 }
 656 
 657 // Implementation of ConstantPoolCache
 658 
 659 ConstantPoolCache* ConstantPoolCache::allocate(ClassLoaderData* loader_data,
 660                                      const intStack& index_map,
 661                                      const intStack& invokedynamic_index_map,
 662                                      const intStack& invokedynamic_map, TRAPS) {
 663 
 664   const int length = index_map.length() + invokedynamic_index_map.length();
 665   int size = ConstantPoolCache::size(length);
 666 
 667   return new (loader_data, size, MetaspaceObj::ConstantPoolCacheType, THREAD)
 668     ConstantPoolCache(length, index_map, invokedynamic_index_map, invokedynamic_map);
 669 }
 670 
 671 void ConstantPoolCache::initialize(const intArray& inverse_index_map,
 672                                    const intArray& invokedynamic_inverse_index_map,
 673                                    const intArray& invokedynamic_references_map) {
 674   for (int i = 0; i < inverse_index_map.length(); i++) {
 675     ConstantPoolCacheEntry* e = entry_at(i);
 676     int original_index = inverse_index_map.at(i);
 677     e->initialize_entry(original_index);
 678     assert(entry_at(i) == e, "sanity");
 679   }
 680 
 681   // Append invokedynamic entries at the end
 682   int invokedynamic_offset = inverse_index_map.length();
 683   for (int i = 0; i < invokedynamic_inverse_index_map.length(); i++) {
 684     int offset = i + invokedynamic_offset;
 685     ConstantPoolCacheEntry* e = entry_at(offset);
 686     int original_index = invokedynamic_inverse_index_map.at(i);
 687     e->initialize_entry(original_index);
 688     assert(entry_at(offset) == e, "sanity");
 689   }
 690 
 691   for (int ref = 0; ref < invokedynamic_references_map.length(); ref++) {
 692     const int cpci = invokedynamic_references_map.at(ref);
 693     if (cpci >= 0) {
 694 #ifdef ASSERT
 695       // invokedynamic and invokehandle have more entries; check if they
 696       // all point to the same constant pool cache entry.
 697       for (int entry = 1; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {
 698         const int cpci_next = invokedynamic_references_map.at(ref + entry);
 699         assert(cpci == cpci_next, "%d == %d", cpci, cpci_next);
 700       }
 701 #endif
 702       entry_at(cpci)->initialize_resolved_reference_index(ref);
 703       ref += ConstantPoolCacheEntry::_indy_resolved_references_entries - 1;  // skip extra entries
 704     }
 705   }
 706 }
 707 
 708 void ConstantPoolCache::verify_just_initialized() {
 709   DEBUG_ONLY(walk_entries_for_initialization(/*check_only = */ true));
 710 }
 711 
 712 void ConstantPoolCache::remove_unshareable_info() {
 713   walk_entries_for_initialization(/*check_only = */ false);
 714 }
 715 
 716 void ConstantPoolCache::walk_entries_for_initialization(bool check_only) {
 717   assert(DumpSharedSpaces, "sanity");
 718   // When dumping the archive, we want to clean up the ConstantPoolCache
 719   // to remove any effect of linking due to the execution of Java code --
 720   // each ConstantPoolCacheEntry will have the same contents as if
 721   // ConstantPoolCache::initialize has just returned:
 722   //
 723   // - We keep the ConstantPoolCache::constant_pool_index() bits for all entries.
 724   // - We keep the "f2" field for entries used by invokedynamic and invokehandle
 725   // - All other bits in the entries are cleared to zero.
 726   ResourceMark rm;
 727 
 728   InstanceKlass* ik = constant_pool()->pool_holder();
 729   bool* f2_used = NEW_RESOURCE_ARRAY(bool, length());
 730   memset(f2_used, 0, sizeof(bool) * length());
 731 
 732   // Find all the slots that we need to preserve f2
 733   for (int i = 0; i < ik->methods()->length(); i++) {
 734     Method* m = ik->methods()->at(i);
 735     RawBytecodeStream bcs(m);
 736     while (!bcs.is_last_bytecode()) {
 737       Bytecodes::Code opcode = bcs.raw_next();
 738       switch (opcode) {
 739       case Bytecodes::_invokedynamic: {
 740           int index = Bytes::get_native_u4(bcs.bcp() + 1);
 741           int cp_cache_index = constant_pool()->invokedynamic_cp_cache_index(index);
 742           f2_used[cp_cache_index] = 1;
 743         }
 744         break;
 745       case Bytecodes::_invokehandle: {
 746           int cp_cache_index = Bytes::get_native_u2(bcs.bcp() + 1);
 747           f2_used[cp_cache_index] = 1;
 748         }
 749         break;
 750       default:
 751         break;
 752       }
 753     }
 754   }
 755 
 756   if (check_only) {
 757     DEBUG_ONLY(
 758       for (int i=0; i<length(); i++) {
 759         entry_at(i)->verify_just_initialized(f2_used[i]);
 760       })
 761   } else {
 762     for (int i=0; i<length(); i++) {
 763       entry_at(i)->reinitialize(f2_used[i]);
 764     }
 765   }
 766 }
 767 
 768 void ConstantPoolCache::deallocate_contents(ClassLoaderData* data) {
 769   assert(!is_shared(), "shared caches are not deallocated");
 770   data->remove_handle(_resolved_references);
 771   set_resolved_references(NULL);
 772   MetadataFactory::free_array<u2>(data, _reference_map);
 773   set_reference_map(NULL);
 774 }
 775 
 776 #if INCLUDE_CDS_JAVA_HEAP
 777 oop ConstantPoolCache::archived_references() {
 778   if (CompressedOops::is_null(_archived_references)) {
 779     return NULL;
 780   }
 781   return MetaspaceShared::materialize_archived_object(CompressedOops::decode_not_null(_archived_references));
 782 }
 783 
 784 void ConstantPoolCache::set_archived_references(oop o) {
 785   assert(DumpSharedSpaces, "called only during runtime");
 786   _archived_references = CompressedOops::encode(o);
 787 }
 788 #endif
 789 
 790 #if INCLUDE_JVMTI
 791 // RedefineClasses() API support:
 792 // If any entry of this ConstantPoolCache points to any of
 793 // old_methods, replace it with the corresponding new_method.
 794 void ConstantPoolCache::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
 795   for (int i = 0; i < length(); i++) {
 796     ConstantPoolCacheEntry* entry = entry_at(i);
 797     Method* old_method = entry->get_interesting_method_entry(holder);
 798     if (old_method == NULL || !old_method->is_old()) {
 799       continue; // skip uninteresting entries
 800     }
 801     if (old_method->is_deleted()) {
 802       // clean up entries with deleted methods
 803       entry->initialize_entry(entry->constant_pool_index());
 804       continue;
 805     }
 806     Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
 807 
 808     assert(new_method != NULL, "method_with_idnum() should not be NULL");
 809     assert(old_method != new_method, "sanity check");
 810 
 811     entry_at(i)->adjust_method_entry(old_method, new_method, trace_name_printed);
 812   }
 813 }
 814 
 815 // the constant pool cache should never contain old or obsolete methods
 816 bool ConstantPoolCache::check_no_old_or_obsolete_entries() {
 817   for (int i = 1; i < length(); i++) {
 818     if (entry_at(i)->get_interesting_method_entry(NULL) != NULL &&
 819         !entry_at(i)->check_no_old_or_obsolete_entries()) {
 820       return false;
 821     }
 822   }
 823   return true;
 824 }
 825 
 826 void ConstantPoolCache::dump_cache() {
 827   for (int i = 1; i < length(); i++) {
 828     if (entry_at(i)->get_interesting_method_entry(NULL) != NULL) {
 829       entry_at(i)->print(tty, i);
 830     }
 831   }
 832 }
 833 #endif // INCLUDE_JVMTI
 834 
 835 void ConstantPoolCache::metaspace_pointers_do(MetaspaceClosure* it) {
 836   log_trace(cds)("Iter(ConstantPoolCache): %p", this);
 837   it->push(&_constant_pool);
 838   it->push(&_reference_map);
 839 }
 840 
 841 // Printing
 842 
 843 void ConstantPoolCache::print_on(outputStream* st) const {
 844   assert(is_constantPoolCache(), "obj must be constant pool cache");
 845   st->print_cr("%s", internal_name());
 846   // print constant pool cache entries
 847   for (int i = 0; i < length(); i++) entry_at(i)->print(st, i);
 848 }
 849 
 850 void ConstantPoolCache::print_value_on(outputStream* st) const {
 851   assert(is_constantPoolCache(), "obj must be constant pool cache");
 852   st->print("cache [%d]", length());
 853   print_address_on(st);
 854   st->print(" for ");
 855   constant_pool()->print_value_on(st);
 856 }
 857 
 858 
 859 // Verification
 860 
 861 void ConstantPoolCache::verify_on(outputStream* st) {
 862   guarantee(is_constantPoolCache(), "obj must be constant pool cache");
 863   // print constant pool cache entries
 864   for (int i = 0; i < length(); i++) entry_at(i)->verify(st);
 865 }