1 /*
   2  * Copyright (c) 1998, 2019, 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/heapShared.hpp"
  34 #include "memory/metadataFactory.hpp"
  35 #include "memory/metaspaceClosure.hpp"
  36 #include "memory/metaspaceShared.hpp"
  37 #include "memory/resourceArea.hpp"
  38 #include "memory/universe.hpp"
  39 #include "oops/access.inline.hpp"
  40 #include "oops/constantPool.inline.hpp"
  41 #include "oops/cpCache.inline.hpp"
  42 #include "oops/objArrayOop.inline.hpp"
  43 #include "oops/oop.inline.hpp"
  44 #include "prims/methodHandles.hpp"
  45 #include "runtime/atomic.hpp"
  46 #include "runtime/handles.inline.hpp"
  47 #include "runtime/orderAccess.hpp"
  48 #include "utilities/macros.hpp"
  49 
  50 // Implementation of ConstantPoolCacheEntry
  51 
  52 void ConstantPoolCacheEntry::initialize_entry(int index) {
  53   assert(0 < index && index < 0x10000, "sanity check");
  54   _indices = index;
  55   _f1 = NULL;
  56   _f2 = _flags = 0;
  57   assert(constant_pool_index() == index, "");
  58 }
  59 
  60 void ConstantPoolCacheEntry::verify_just_initialized(bool f2_used) {
  61   assert((_indices & (~cp_index_mask)) == 0, "sanity");
  62   assert(_f1 == NULL, "sanity");
  63   assert(_flags == 0, "sanity");
  64   if (!f2_used) {
  65     assert(_f2 == 0, "sanity");
  66   }
  67 }
  68 
  69 void ConstantPoolCacheEntry::reinitialize(bool f2_used) {
  70   _indices &= cp_index_mask;
  71   _f1 = NULL;
  72   _flags = 0;
  73   if (!f2_used) {
  74     _f2 = 0;
  75   }
  76 }
  77 
  78 int ConstantPoolCacheEntry::make_flags(TosState state,
  79                                        int option_bits,
  80                                        int field_index_or_method_params) {
  81   assert(state < number_of_states, "Invalid state in make_flags");
  82   int f = ((int)state << tos_state_shift) | option_bits | field_index_or_method_params;
  83   // Preserve existing flag bit values
  84   // The low bits are a field offset, or else the method parameter size.
  85 #ifdef ASSERT
  86   TosState old_state = flag_state();
  87   assert(old_state == (TosState)0 || old_state == state,
  88          "inconsistent cpCache flags state");
  89 #endif
  90   return (_flags | f) ;
  91 }
  92 
  93 void ConstantPoolCacheEntry::set_bytecode_1(Bytecodes::Code code) {
  94 #ifdef ASSERT
  95   // Read once.
  96   volatile Bytecodes::Code c = bytecode_1();
  97   assert(c == 0 || c == code || code == 0, "update must be consistent");
  98 #endif
  99   // Need to flush pending stores here before bytecode is written.
 100   OrderAccess::release_store(&_indices, _indices | ((u_char)code << bytecode_1_shift));
 101 }
 102 
 103 void ConstantPoolCacheEntry::set_bytecode_2(Bytecodes::Code code) {
 104 #ifdef ASSERT
 105   // Read once.
 106   volatile Bytecodes::Code c = bytecode_2();
 107   assert(c == 0 || c == code || code == 0, "update must be consistent");
 108 #endif
 109   // Need to flush pending stores here before bytecode is written.
 110   OrderAccess::release_store(&_indices, _indices | ((u_char)code << bytecode_2_shift));
 111 }
 112 
 113 // Sets f1, ordering with previous writes.
 114 void ConstantPoolCacheEntry::release_set_f1(Metadata* f1) {
 115   assert(f1 != NULL, "");
 116   OrderAccess::release_store(&_f1, f1);
 117 }
 118 
 119 void ConstantPoolCacheEntry::set_indy_resolution_failed() {
 120   OrderAccess::release_store(&_flags, _flags | (1 << indy_resolution_failed_shift));
 121 }
 122 
 123 // Note that concurrent update of both bytecodes can leave one of them
 124 // reset to zero.  This is harmless; the interpreter will simply re-resolve
 125 // the damaged entry.  More seriously, the memory synchronization is needed
 126 // to flush other fields (f1, f2) completely to memory before the bytecodes
 127 // are updated, lest other processors see a non-zero bytecode but zero f1/f2.
 128 void ConstantPoolCacheEntry::set_field(Bytecodes::Code get_code,
 129                                        Bytecodes::Code put_code,
 130                                        Klass* field_holder,
 131                                        int field_index,
 132                                        int field_offset,
 133                                        TosState field_type,
 134                                        bool is_final,
 135                                        bool is_volatile,
 136                                        Klass* root_klass) {
 137   set_f1(field_holder);
 138   set_f2(field_offset);
 139   assert((field_index & field_index_mask) == field_index,
 140          "field index does not fit in low flag bits");
 141   set_field_flags(field_type,
 142                   ((is_volatile ? 1 : 0) << is_volatile_shift) |
 143                   ((is_final    ? 1 : 0) << is_final_shift),
 144                   field_index);
 145   set_bytecode_1(get_code);
 146   set_bytecode_2(put_code);
 147   NOT_PRODUCT(verify(tty));
 148 }
 149 
 150 void ConstantPoolCacheEntry::set_parameter_size(int value) {
 151   // This routine is called only in corner cases where the CPCE is not yet initialized.
 152   // See AbstractInterpreter::deopt_continue_after_entry.
 153   assert(_flags == 0 || parameter_size() == 0 || parameter_size() == value,
 154          "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
 155   // Setting the parameter size by itself is only safe if the
 156   // current value of _flags is 0, otherwise another thread may have
 157   // updated it and we don't want to overwrite that value.  Don't
 158   // bother trying to update it once it's nonzero but always make
 159   // sure that the final parameter size agrees with what was passed.
 160   if (_flags == 0) {
 161     intx newflags = (value & parameter_size_mask);
 162     Atomic::cmpxchg(newflags, &_flags, (intx)0);
 163   }
 164   guarantee(parameter_size() == value,
 165             "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
 166 }
 167 
 168 void ConstantPoolCacheEntry::set_direct_or_vtable_call(Bytecodes::Code invoke_code,
 169                                                        const methodHandle& method,
 170                                                        int vtable_index,
 171                                                        bool sender_is_interface,
 172                                                        InstanceKlass* pool_holder) {
 173   bool is_vtable_call = (vtable_index >= 0);  // FIXME: split this method on this boolean
 174   assert(method->interpreter_entry() != NULL, "should have been set at this point");
 175   assert(!method->is_obsolete(),  "attempt to write obsolete method to cpCache");
 176 
 177   int byte_no = -1;
 178   bool change_to_virtual = false;
 179   InstanceKlass* holder = NULL;  // have to declare this outside the switch
 180   switch (invoke_code) {
 181     case Bytecodes::_invokeinterface:
 182       holder = method->method_holder();
 183       // check for private interface method invocations
 184       if (vtable_index == Method::nonvirtual_vtable_index && holder->is_interface() ) {
 185         assert(method->is_private(), "unexpected non-private method");
 186         assert(method->can_be_statically_bound(), "unexpected non-statically-bound method");
 187         // set_f2_as_vfinal_method checks if is_vfinal flag is true.
 188         set_method_flags(as_TosState(method->result_type()),
 189                          (                             1      << is_vfinal_shift) |
 190                          ((method->is_final_method() ? 1 : 0) << is_final_shift),
 191                          method()->size_of_parameters());
 192         set_f2_as_vfinal_method(method());
 193         byte_no = 2;
 194         set_f1(holder); // interface klass*
 195         break;
 196       }
 197       else {
 198         // We get here from InterpreterRuntime::resolve_invoke when an invokeinterface
 199         // instruction links to a non-interface method (in Object). This can happen when
 200         // an interface redeclares an Object method (like CharSequence declaring toString())
 201         // or when invokeinterface is used explicitly.
 202         // In that case, the method has no itable index and must be invoked as a virtual.
 203         // Set a flag to keep track of this corner case.
 204         assert(holder->is_interface() || holder == SystemDictionary::Object_klass(), "unexpected holder class");
 205         assert(method->is_public(), "Calling non-public method in Object with invokeinterface");
 206         change_to_virtual = true;
 207 
 208         // ...and fall through as if we were handling invokevirtual:
 209       }
 210     case Bytecodes::_invokevirtual:
 211       {
 212         if (!is_vtable_call) {
 213           assert(method->can_be_statically_bound(), "");
 214           // set_f2_as_vfinal_method checks if is_vfinal flag is true.
 215           set_method_flags(as_TosState(method->result_type()),
 216                            (                             1      << is_vfinal_shift) |
 217                            ((method->is_final_method() ? 1 : 0) << is_final_shift)  |
 218                            ((change_to_virtual         ? 1 : 0) << is_forced_virtual_shift),
 219                            method()->size_of_parameters());
 220           set_f2_as_vfinal_method(method());
 221         } else {
 222           assert(!method->can_be_statically_bound(), "");
 223           assert(vtable_index >= 0, "valid index");
 224           assert(!method->is_final_method(), "sanity");
 225           set_method_flags(as_TosState(method->result_type()),
 226                            ((change_to_virtual ? 1 : 0) << is_forced_virtual_shift),
 227                            method()->size_of_parameters());
 228           set_f2(vtable_index);
 229         }
 230         byte_no = 2;
 231         break;
 232       }
 233 
 234     case Bytecodes::_invokespecial:
 235     case Bytecodes::_invokestatic:
 236       assert(!is_vtable_call, "");
 237       // Note:  Read and preserve the value of the is_vfinal flag on any
 238       // invokevirtual bytecode shared with this constant pool cache entry.
 239       // It is cheap and safe to consult is_vfinal() at all times.
 240       // Once is_vfinal is set, it must stay that way, lest we get a dangling oop.
 241       set_method_flags(as_TosState(method->result_type()),
 242                        ((is_vfinal()               ? 1 : 0) << is_vfinal_shift) |
 243                        ((method->is_final_method() ? 1 : 0) << is_final_shift),
 244                        method()->size_of_parameters());
 245       set_f1(method());
 246       byte_no = 1;
 247       break;
 248     default:
 249       ShouldNotReachHere();
 250       break;
 251   }
 252 
 253   // Note:  byte_no also appears in TemplateTable::resolve.
 254   if (byte_no == 1) {
 255     assert(invoke_code != Bytecodes::_invokevirtual &&
 256            invoke_code != Bytecodes::_invokeinterface, "");
 257     bool do_resolve = true;
 258     // Don't mark invokespecial to method as resolved if sender is an interface.  The receiver
 259     // has to be checked that it is a subclass of the current class every time this bytecode
 260     // is executed.
 261     if (invoke_code == Bytecodes::_invokespecial && sender_is_interface &&
 262         method->name() != vmSymbols::object_initializer_name()) {
 263       do_resolve = false;
 264     }
 265     // Don't mark invokestatic to method as resolved if the holder class has not yet completed
 266     // initialization. An invokestatic must only proceed if the class is initialized, but if
 267     // we resolve it before then that class initialization check is skipped. However if the call
 268     // is from the same class we can resolve as we must be executing with <clinit> on our call stack.
 269     if (invoke_code == Bytecodes::_invokestatic &&
 270         !method->method_holder()->is_initialized() &&
 271         method->method_holder() != pool_holder) {
 272       do_resolve = false;
 273     }
 274     if (do_resolve) {
 275       assert(method->method_holder()->is_initialized() ||
 276              method->method_holder()->is_reentrant_initialization(Thread::current()),
 277              "invalid class initalization state");
 278       set_bytecode_1(invoke_code);
 279     }
 280   } else if (byte_no == 2)  {
 281     if (change_to_virtual) {
 282       assert(invoke_code == Bytecodes::_invokeinterface, "");
 283       // NOTE: THIS IS A HACK - BE VERY CAREFUL!!!
 284       //
 285       // Workaround for the case where we encounter an invokeinterface, but we
 286       // should really have an _invokevirtual since the resolved method is a
 287       // virtual method in java.lang.Object. This is a corner case in the spec
 288       // but is presumably legal. javac does not generate this code.
 289       //
 290       // We do not set bytecode_1() to _invokeinterface, because that is the
 291       // bytecode # used by the interpreter to see if it is resolved.  In this
 292       // case, the method gets reresolved with caller for each interface call
 293       // because the actual selected method may not be public.
 294       //
 295       // We set bytecode_2() to _invokevirtual.
 296       // See also interpreterRuntime.cpp. (8/25/2000)
 297     } else {
 298       assert(invoke_code == Bytecodes::_invokevirtual ||
 299              (invoke_code == Bytecodes::_invokeinterface &&
 300               ((method->is_private() ||
 301                 (method->is_final() && method->method_holder() == SystemDictionary::Object_klass())))),
 302              "unexpected invocation mode");
 303       if (invoke_code == Bytecodes::_invokeinterface &&
 304           (method->is_private() || method->is_final())) {
 305         // We set bytecode_1() to _invokeinterface, because that is the
 306         // bytecode # used by the interpreter to see if it is resolved.
 307         // We set bytecode_2() to _invokevirtual.
 308         set_bytecode_1(invoke_code);
 309       }
 310     }
 311     // set up for invokevirtual, even if linking for invokeinterface also:
 312     set_bytecode_2(Bytecodes::_invokevirtual);
 313   } else {
 314     ShouldNotReachHere();
 315   }
 316   NOT_PRODUCT(verify(tty));
 317 }
 318 
 319 void ConstantPoolCacheEntry::set_direct_call(Bytecodes::Code invoke_code, const methodHandle& method,
 320                                              bool sender_is_interface, InstanceKlass* pool_holder) {
 321   int index = Method::nonvirtual_vtable_index;
 322   // index < 0; FIXME: inline and customize set_direct_or_vtable_call
 323   set_direct_or_vtable_call(invoke_code, method, index, sender_is_interface, pool_holder);
 324 }
 325 
 326 void ConstantPoolCacheEntry::set_vtable_call(Bytecodes::Code invoke_code, const methodHandle& method, int index) {
 327   // either the method is a miranda or its holder should accept the given index
 328   assert(method->method_holder()->is_interface() || method->method_holder()->verify_vtable_index(index), "");
 329   // index >= 0; FIXME: inline and customize set_direct_or_vtable_call
 330   set_direct_or_vtable_call(invoke_code, method, index, false, NULL /* not used */);
 331 }
 332 
 333 void ConstantPoolCacheEntry::set_itable_call(Bytecodes::Code invoke_code,
 334                                              Klass* referenced_klass,
 335                                              const methodHandle& method, int index) {
 336   assert(method->method_holder()->verify_itable_index(index), "");
 337   assert(invoke_code == Bytecodes::_invokeinterface, "");
 338   InstanceKlass* interf = method->method_holder();
 339   assert(interf->is_interface(), "must be an interface");
 340   assert(!method->is_final_method(), "interfaces do not have final methods; cannot link to one here");
 341   set_f1(referenced_klass);
 342   set_f2((intx)method());
 343   set_method_flags(as_TosState(method->result_type()),
 344                    0,  // no option bits
 345                    method()->size_of_parameters());
 346   set_bytecode_1(Bytecodes::_invokeinterface);
 347 }
 348 
 349 
 350 void ConstantPoolCacheEntry::set_method_handle(const constantPoolHandle& cpool, const CallInfo &call_info) {
 351   set_method_handle_common(cpool, Bytecodes::_invokehandle, call_info);
 352 }
 353 
 354 void ConstantPoolCacheEntry::set_dynamic_call(const constantPoolHandle& cpool, const CallInfo &call_info) {
 355   set_method_handle_common(cpool, Bytecodes::_invokedynamic, call_info);
 356 }
 357 
 358 void ConstantPoolCacheEntry::set_method_handle_common(const constantPoolHandle& cpool,
 359                                                       Bytecodes::Code invoke_code,
 360                                                       const CallInfo &call_info) {
 361   // NOTE: This CPCE can be the subject of data races.
 362   // There are three words to update: flags, refs[f2], f1 (in that order).
 363   // Writers must store all other values before f1.
 364   // Readers must test f1 first for non-null before reading other fields.
 365   // Competing writers must acquire exclusive access via a lock.
 366   // A losing writer waits on the lock until the winner writes f1 and leaves
 367   // the lock, so that when the losing writer returns, he can use the linked
 368   // cache entry.
 369 
 370   objArrayHandle resolved_references(Thread::current(), cpool->resolved_references());
 371   // Use the resolved_references() lock for this cpCache entry.
 372   // resolved_references are created for all classes with Invokedynamic, MethodHandle
 373   // or MethodType constant pool cache entries.
 374   assert(resolved_references() != NULL,
 375          "a resolved_references array should have been created for this class");
 376   ObjectLocker ol(resolved_references, Thread::current());
 377   if (!is_f1_null()) {
 378     return;
 379   }
 380 
 381   if (indy_resolution_failed()) {
 382     // Before we got here, another thread got a LinkageError exception during
 383     // resolution.  Ignore our success and throw their exception.
 384     ConstantPoolCache* cpCache = cpool->cache();
 385     int index = -1;
 386     for (int i = 0; i < cpCache->length(); i++) {
 387       if (cpCache->entry_at(i) == this) {
 388         index = i;
 389         break;
 390       }
 391     }
 392     guarantee(index >= 0, "Didn't find cpCache entry!");
 393     int encoded_index = ResolutionErrorTable::encode_cpcache_index(
 394                           ConstantPool::encode_invokedynamic_index(index));
 395     Thread* THREAD = Thread::current();
 396     ConstantPool::throw_resolution_error(cpool, encoded_index, THREAD);
 397     return;
 398   }
 399 
 400   const methodHandle adapter = call_info.resolved_method();
 401   const Handle appendix      = call_info.resolved_appendix();
 402   const bool has_appendix    = appendix.not_null();
 403 
 404   // Write the flags.
 405   // MHs and indy are always sig-poly and have a local signature.
 406   set_method_flags(as_TosState(adapter->result_type()),
 407                    ((has_appendix    ? 1 : 0) << has_appendix_shift        ) |
 408                    (                   1      << has_local_signature_shift ) |
 409                    (                   1      << is_final_shift            ),
 410                    adapter->size_of_parameters());
 411 
 412   if (TraceInvokeDynamic) {
 413     ttyLocker ttyl;
 414     tty->print_cr("set_method_handle bc=%d appendix=" PTR_FORMAT "%s method=" PTR_FORMAT " (local signature) ",
 415                   invoke_code,
 416                   p2i(appendix()),
 417                   (has_appendix ? "" : " (unused)"),
 418                   p2i(adapter()));
 419     adapter->print();
 420     if (has_appendix)  appendix()->print();
 421   }
 422 
 423   // Method handle invokes and invokedynamic sites use both cp cache words.
 424   // refs[f2], if not null, contains a value passed as a trailing argument to the adapter.
 425   // In the general case, this could be the call site's MethodType,
 426   // for use with java.lang.Invokers.checkExactType, or else a CallSite object.
 427   // f1 contains the adapter method which manages the actual call.
 428   // In the general case, this is a compiled LambdaForm.
 429   // (The Java code is free to optimize these calls by binding other
 430   // sorts of methods and appendices to call sites.)
 431   // JVM-level linking is via f1, as if for invokespecial, and signatures are erased.
 432   // The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.
 433   // Even with the appendix, the method will never take more than 255 parameter slots.
 434   //
 435   // This means that given a call site like (List)mh.invoke("foo"),
 436   // the f1 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',
 437   // not '(Ljava/lang/String;)Ljava/util/List;'.
 438   // The fact that String and List are involved is encoded in the MethodType in refs[f2].
 439   // This allows us to create fewer Methods, while keeping type safety.
 440   //
 441 
 442   // Store appendix, if any.
 443   if (has_appendix) {
 444     const int appendix_index = f2_as_index();
 445     assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");
 446     assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
 447     resolved_references->obj_at_put(appendix_index, appendix());
 448   }
 449 
 450   release_set_f1(adapter());  // This must be the last one to set (see NOTE above)!
 451 
 452   // The interpreter assembly code does not check byte_2,
 453   // but it is used by is_resolved, method_if_resolved, etc.
 454   set_bytecode_1(invoke_code);
 455   NOT_PRODUCT(verify(tty));
 456   if (TraceInvokeDynamic) {
 457     ttyLocker ttyl;
 458     this->print(tty, 0);
 459   }
 460 
 461   assert(has_appendix == this->has_appendix(), "proper storage of appendix flag");
 462   assert(this->has_local_signature(), "proper storage of signature flag");
 463 }
 464 
 465 bool ConstantPoolCacheEntry::save_and_throw_indy_exc(
 466   const constantPoolHandle& cpool, int cpool_index, int index, constantTag tag, TRAPS) {
 467 
 468   assert(HAS_PENDING_EXCEPTION, "No exception got thrown!");
 469   assert(PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass()),
 470          "No LinkageError exception");
 471 
 472   // Use the resolved_references() lock for this cpCache entry.
 473   // resolved_references are created for all classes with Invokedynamic, MethodHandle
 474   // or MethodType constant pool cache entries.
 475   objArrayHandle resolved_references(Thread::current(), cpool->resolved_references());
 476   assert(resolved_references() != NULL,
 477          "a resolved_references array should have been created for this class");
 478   ObjectLocker ol(resolved_references, THREAD);
 479 
 480   // if f1 is not null or the indy_resolution_failed flag is set then another
 481   // thread either succeeded in resolving the method or got a LinkageError
 482   // exception, before this thread was able to record its failure.  So, clear
 483   // this thread's exception and return false so caller can use the earlier
 484   // thread's result.
 485   if (!is_f1_null() || indy_resolution_failed()) {
 486     CLEAR_PENDING_EXCEPTION;
 487     return false;
 488   }
 489 
 490   Symbol* error = PENDING_EXCEPTION->klass()->name();
 491   Symbol* message = java_lang_Throwable::detail_message(PENDING_EXCEPTION);
 492 
 493   SystemDictionary::add_resolution_error(cpool, index, error, message);
 494   set_indy_resolution_failed();
 495   return true;
 496 }
 497 
 498 Method* ConstantPoolCacheEntry::method_if_resolved(const constantPoolHandle& cpool) {
 499   // Decode the action of set_method and set_interface_call
 500   Bytecodes::Code invoke_code = bytecode_1();
 501   if (invoke_code != (Bytecodes::Code)0) {
 502     Metadata* f1 = f1_ord();
 503     if (f1 != NULL) {
 504       switch (invoke_code) {
 505       case Bytecodes::_invokeinterface:
 506         assert(f1->is_klass(), "");
 507         return klassItable::method_for_itable_index((InstanceKlass*)f1, f2_as_index());
 508       case Bytecodes::_invokestatic:
 509       case Bytecodes::_invokespecial:
 510         assert(!has_appendix(), "");
 511       case Bytecodes::_invokehandle:
 512       case Bytecodes::_invokedynamic:
 513         assert(f1->is_method(), "");
 514         return (Method*)f1;
 515       default:
 516         break;
 517       }
 518     }
 519   }
 520   invoke_code = bytecode_2();
 521   if (invoke_code != (Bytecodes::Code)0) {
 522     switch (invoke_code) {
 523     case Bytecodes::_invokevirtual:
 524       if (is_vfinal()) {
 525         // invokevirtual
 526         Method* m = f2_as_vfinal_method();
 527         assert(m->is_method(), "");
 528         return m;
 529       } else {
 530         int holder_index = cpool->uncached_klass_ref_index_at(constant_pool_index());
 531         if (cpool->tag_at(holder_index).is_klass()) {
 532           Klass* klass = cpool->resolved_klass_at(holder_index);
 533           return klass->method_at_vtable(f2_as_index());
 534         }
 535       }
 536       break;
 537     default:
 538       break;
 539     }
 540   }
 541   return NULL;
 542 }
 543 
 544 
 545 oop ConstantPoolCacheEntry::appendix_if_resolved(const constantPoolHandle& cpool) {
 546   if (!has_appendix())
 547     return NULL;
 548   const int ref_index = f2_as_index();
 549   objArrayOop resolved_references = cpool->resolved_references();
 550   return resolved_references->obj_at(ref_index);
 551 }
 552 
 553 
 554 #if INCLUDE_JVMTI
 555 
 556 void log_adjust(const char* entry_type, Method* old_method, Method* new_method, bool* trace_name_printed) {
 557   if (log_is_enabled(Info, redefine, class, update)) {
 558     ResourceMark rm;
 559     if (!(*trace_name_printed)) {
 560       log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
 561       *trace_name_printed = true;
 562     }
 563     log_debug(redefine, class, update, constantpool)
 564           ("cpc %s entry update: %s(%s)", entry_type, new_method->name()->as_C_string(), new_method->signature()->as_C_string());
 565   }
 566 }
 567 
 568 // RedefineClasses() API support:
 569 // If this ConstantPoolCacheEntry refers to old_method then update it
 570 // to refer to new_method.
 571 void ConstantPoolCacheEntry::adjust_method_entry(Method* old_method,
 572        Method* new_method, bool * trace_name_printed) {
 573 
 574   if (is_vfinal()) {
 575     // virtual and final so _f2 contains method ptr instead of vtable index
 576     if (f2_as_vfinal_method() == old_method) {
 577       // match old_method so need an update
 578       // NOTE: can't use set_f2_as_vfinal_method as it asserts on different values
 579       _f2 = (intptr_t)new_method;
 580       log_adjust("vfinal", old_method, new_method, trace_name_printed);
 581     }
 582     return;
 583   }
 584 
 585   assert (_f1 != NULL, "should not call with uninteresting entry");
 586 
 587   if (!(_f1->is_method())) {
 588     // _f1 is a Klass* for an interface, _f2 is the method
 589     if (f2_as_interface_method() == old_method) {
 590       _f2 = (intptr_t)new_method;
 591       log_adjust("interface", old_method, new_method, trace_name_printed);
 592     }
 593   } else if (_f1 == old_method) {
 594     _f1 = new_method;
 595     log_adjust("special, static or dynamic", old_method, new_method, trace_name_printed);
 596   }
 597 }
 598 
 599 // a constant pool cache entry should never contain old or obsolete methods
 600 bool ConstantPoolCacheEntry::check_no_old_or_obsolete_entries() {
 601   Method* m = get_interesting_method_entry();
 602   // return false if m refers to a non-deleted old or obsolete method
 603   if (m != NULL) {
 604     assert(m->is_valid() && m->is_method(), "m is a valid method");
 605     return !m->is_old() && !m->is_obsolete(); // old is always set for old and obsolete
 606   } else {
 607     return true;
 608   }
 609 }
 610 
 611 Method* ConstantPoolCacheEntry::get_interesting_method_entry() {
 612   if (!is_method_entry()) {
 613     // not a method entry so not interesting by default
 614     return NULL;
 615   }
 616   Method* m = NULL;
 617   if (is_vfinal()) {
 618     // virtual and final so _f2 contains method ptr instead of vtable index
 619     m = f2_as_vfinal_method();
 620   } else if (is_f1_null()) {
 621     // NULL _f1 means this is a virtual entry so also not interesting
 622     return NULL;
 623   } else {
 624     if (!(_f1->is_method())) {
 625       // _f1 is a Klass* for an interface
 626       m = f2_as_interface_method();
 627     } else {
 628       m = f1_as_method();
 629     }
 630   }
 631   assert(m != NULL && m->is_method(), "sanity check");
 632   if (m == NULL || !m->is_method()) {
 633     return NULL;
 634   }
 635   return m;
 636 }
 637 #endif // INCLUDE_JVMTI
 638 
 639 void ConstantPoolCacheEntry::print(outputStream* st, int index) const {
 640   // print separator
 641   if (index == 0) st->print_cr("                 -------------");
 642   // print entry
 643   st->print("%3d  (" PTR_FORMAT ")  ", index, (intptr_t)this);
 644   st->print_cr("[%02x|%02x|%5d]", bytecode_2(), bytecode_1(),
 645                constant_pool_index());
 646   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f1);
 647   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f2);
 648   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_flags);
 649   st->print_cr("                 -------------");
 650 }
 651 
 652 void ConstantPoolCacheEntry::verify(outputStream* st) const {
 653   // not implemented yet
 654 }
 655 
 656 // Implementation of ConstantPoolCache
 657 
 658 ConstantPoolCache* ConstantPoolCache::allocate(ClassLoaderData* loader_data,
 659                                      const intStack& index_map,
 660                                      const intStack& invokedynamic_index_map,
 661                                      const intStack& invokedynamic_map, TRAPS) {
 662 
 663   const int length = index_map.length() + invokedynamic_index_map.length();
 664   int size = ConstantPoolCache::size(length);
 665 
 666   return new (loader_data, size, MetaspaceObj::ConstantPoolCacheType, THREAD)
 667     ConstantPoolCache(length, index_map, invokedynamic_index_map, invokedynamic_map);
 668 }
 669 
 670 void ConstantPoolCache::initialize(const intArray& inverse_index_map,
 671                                    const intArray& invokedynamic_inverse_index_map,
 672                                    const intArray& invokedynamic_references_map) {
 673   for (int i = 0; i < inverse_index_map.length(); i++) {
 674     ConstantPoolCacheEntry* e = entry_at(i);
 675     int original_index = inverse_index_map.at(i);
 676     e->initialize_entry(original_index);
 677     assert(entry_at(i) == e, "sanity");
 678   }
 679 
 680   // Append invokedynamic entries at the end
 681   int invokedynamic_offset = inverse_index_map.length();
 682   for (int i = 0; i < invokedynamic_inverse_index_map.length(); i++) {
 683     int offset = i + invokedynamic_offset;
 684     ConstantPoolCacheEntry* e = entry_at(offset);
 685     int original_index = invokedynamic_inverse_index_map.at(i);
 686     e->initialize_entry(original_index);
 687     assert(entry_at(offset) == e, "sanity");
 688   }
 689 
 690   for (int ref = 0; ref < invokedynamic_references_map.length(); ref++) {
 691     const int cpci = invokedynamic_references_map.at(ref);
 692     if (cpci >= 0) {
 693       entry_at(cpci)->initialize_resolved_reference_index(ref);
 694     }
 695   }
 696 }
 697 
 698 void ConstantPoolCache::verify_just_initialized() {
 699   DEBUG_ONLY(walk_entries_for_initialization(/*check_only = */ true));
 700 }
 701 
 702 void ConstantPoolCache::remove_unshareable_info() {
 703   walk_entries_for_initialization(/*check_only = */ false);
 704 }
 705 
 706 void ConstantPoolCache::walk_entries_for_initialization(bool check_only) {
 707   assert(DumpSharedSpaces, "sanity");
 708   // When dumping the archive, we want to clean up the ConstantPoolCache
 709   // to remove any effect of linking due to the execution of Java code --
 710   // each ConstantPoolCacheEntry will have the same contents as if
 711   // ConstantPoolCache::initialize has just returned:
 712   //
 713   // - We keep the ConstantPoolCache::constant_pool_index() bits for all entries.
 714   // - We keep the "f2" field for entries used by invokedynamic and invokehandle
 715   // - All other bits in the entries are cleared to zero.
 716   ResourceMark rm;
 717 
 718   InstanceKlass* ik = constant_pool()->pool_holder();
 719   bool* f2_used = NEW_RESOURCE_ARRAY(bool, length());
 720   memset(f2_used, 0, sizeof(bool) * length());
 721 
 722   // Find all the slots that we need to preserve f2
 723   for (int i = 0; i < ik->methods()->length(); i++) {
 724     Method* m = ik->methods()->at(i);
 725     RawBytecodeStream bcs(m);
 726     while (!bcs.is_last_bytecode()) {
 727       Bytecodes::Code opcode = bcs.raw_next();
 728       switch (opcode) {
 729       case Bytecodes::_invokedynamic: {
 730           int index = Bytes::get_native_u4(bcs.bcp() + 1);
 731           int cp_cache_index = constant_pool()->invokedynamic_cp_cache_index(index);
 732           f2_used[cp_cache_index] = 1;
 733         }
 734         break;
 735       case Bytecodes::_invokehandle: {
 736           int cp_cache_index = Bytes::get_native_u2(bcs.bcp() + 1);
 737           f2_used[cp_cache_index] = 1;
 738         }
 739         break;
 740       default:
 741         break;
 742       }
 743     }
 744   }
 745 
 746   if (check_only) {
 747     DEBUG_ONLY(
 748       for (int i=0; i<length(); i++) {
 749         entry_at(i)->verify_just_initialized(f2_used[i]);
 750       })
 751   } else {
 752     for (int i=0; i<length(); i++) {
 753       entry_at(i)->reinitialize(f2_used[i]);
 754     }
 755   }
 756 }
 757 
 758 void ConstantPoolCache::deallocate_contents(ClassLoaderData* data) {
 759   assert(!is_shared(), "shared caches are not deallocated");
 760   data->remove_handle(_resolved_references);
 761   set_resolved_references(NULL);
 762   MetadataFactory::free_array<u2>(data, _reference_map);
 763   set_reference_map(NULL);
 764 }
 765 
 766 #if INCLUDE_CDS_JAVA_HEAP
 767 oop ConstantPoolCache::archived_references() {
 768   if (CompressedOops::is_null(_archived_references)) {
 769     return NULL;
 770   }
 771   return HeapShared::materialize_archived_object(_archived_references);
 772 }
 773 
 774 void ConstantPoolCache::set_archived_references(oop o) {
 775   assert(DumpSharedSpaces, "called only during runtime");
 776   _archived_references = CompressedOops::encode(o);
 777 }
 778 #endif
 779 
 780 #if INCLUDE_JVMTI
 781 // RedefineClasses() API support:
 782 // If any entry of this ConstantPoolCache points to any of
 783 // old_methods, replace it with the corresponding new_method.
 784 void ConstantPoolCache::adjust_method_entries(bool * trace_name_printed) {
 785   for (int i = 0; i < length(); i++) {
 786     ConstantPoolCacheEntry* entry = entry_at(i);
 787     Method* old_method = entry->get_interesting_method_entry();
 788     if (old_method == NULL || !old_method->is_old()) {
 789       continue; // skip uninteresting entries
 790     }
 791     if (old_method->is_deleted()) {
 792       // clean up entries with deleted methods
 793       entry->initialize_entry(entry->constant_pool_index());
 794       continue;
 795     }
 796     Method* new_method = old_method->get_new_method();
 797     entry_at(i)->adjust_method_entry(old_method, new_method, trace_name_printed);
 798   }
 799 }
 800 
 801 // the constant pool cache should never contain old or obsolete methods
 802 bool ConstantPoolCache::check_no_old_or_obsolete_entries() {
 803   for (int i = 1; i < length(); i++) {
 804     if (entry_at(i)->get_interesting_method_entry() != NULL &&
 805         !entry_at(i)->check_no_old_or_obsolete_entries()) {
 806       return false;
 807     }
 808   }
 809   return true;
 810 }
 811 
 812 void ConstantPoolCache::dump_cache() {
 813   for (int i = 1; i < length(); i++) {
 814     if (entry_at(i)->get_interesting_method_entry() != NULL) {
 815       entry_at(i)->print(tty, i);
 816     }
 817   }
 818 }
 819 #endif // INCLUDE_JVMTI
 820 
 821 void ConstantPoolCache::metaspace_pointers_do(MetaspaceClosure* it) {
 822   log_trace(cds)("Iter(ConstantPoolCache): %p", this);
 823   it->push(&_constant_pool);
 824   it->push(&_reference_map);
 825 }
 826 
 827 // Printing
 828 
 829 void ConstantPoolCache::print_on(outputStream* st) const {
 830   st->print_cr("%s", internal_name());
 831   // print constant pool cache entries
 832   for (int i = 0; i < length(); i++) entry_at(i)->print(st, i);
 833 }
 834 
 835 void ConstantPoolCache::print_value_on(outputStream* st) const {
 836   st->print("cache [%d]", length());
 837   print_address_on(st);
 838   st->print(" for ");
 839   constant_pool()->print_value_on(st);
 840 }
 841 
 842 
 843 // Verification
 844 
 845 void ConstantPoolCache::verify_on(outputStream* st) {
 846   // print constant pool cache entries
 847   for (int i = 0; i < length(); i++) entry_at(i)->verify(st);
 848 }