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     if (invoke_code == Bytecodes::_invokestatic) {
 266       if (method->needs_clinit_barrier()) {
 267         if (UseFastClassInitChecks) {
 268           // Template interpreter supports fast class initialization check for invokestatic which
 269           // doesn't require unresolved call site.
 270         } else {
 271           // Don't mark invokestatic to method as resolved if the holder class has not yet completed
 272           // initialization. An invokestatic must only proceed if the class is initialized, but if
 273           // we resolve it before then that class initialization check is skipped.
 274           do_resolve = false;
 275         }
 276       } else {
 277         assert(method->method_holder()->is_initialized() ||
 278                method->method_holder()->is_reentrant_initialization(Thread::current()),
 279                "invalid class initialization state for invoke_static");
 280       }
 281     }
 282     if (do_resolve) {
 283       set_bytecode_1(invoke_code);
 284     }
 285   } else if (byte_no == 2)  {
 286     if (change_to_virtual) {
 287       assert(invoke_code == Bytecodes::_invokeinterface, "");
 288       // NOTE: THIS IS A HACK - BE VERY CAREFUL!!!
 289       //
 290       // Workaround for the case where we encounter an invokeinterface, but we
 291       // should really have an _invokevirtual since the resolved method is a
 292       // virtual method in java.lang.Object. This is a corner case in the spec
 293       // but is presumably legal. javac does not generate this code.
 294       //
 295       // We do not set bytecode_1() to _invokeinterface, because that is the
 296       // bytecode # used by the interpreter to see if it is resolved.  In this
 297       // case, the method gets reresolved with caller for each interface call
 298       // because the actual selected method may not be public.
 299       //
 300       // We set bytecode_2() to _invokevirtual.
 301       // See also interpreterRuntime.cpp. (8/25/2000)
 302     } else {
 303       assert(invoke_code == Bytecodes::_invokevirtual ||
 304              (invoke_code == Bytecodes::_invokeinterface &&
 305               ((method->is_private() ||
 306                 (method->is_final() && method->method_holder() == SystemDictionary::Object_klass())))),
 307              "unexpected invocation mode");
 308       if (invoke_code == Bytecodes::_invokeinterface &&
 309           (method->is_private() || method->is_final())) {
 310         // We set bytecode_1() to _invokeinterface, because that is the
 311         // bytecode # used by the interpreter to see if it is resolved.
 312         // We set bytecode_2() to _invokevirtual.
 313         set_bytecode_1(invoke_code);
 314       }
 315     }
 316     // set up for invokevirtual, even if linking for invokeinterface also:
 317     set_bytecode_2(Bytecodes::_invokevirtual);
 318   } else {
 319     ShouldNotReachHere();
 320   }
 321   NOT_PRODUCT(verify(tty));
 322 }
 323 
 324 void ConstantPoolCacheEntry::set_direct_call(Bytecodes::Code invoke_code, const methodHandle& method,
 325                                              bool sender_is_interface, InstanceKlass* pool_holder) {
 326   int index = Method::nonvirtual_vtable_index;
 327   // index < 0; FIXME: inline and customize set_direct_or_vtable_call
 328   set_direct_or_vtable_call(invoke_code, method, index, sender_is_interface, pool_holder);
 329 }
 330 
 331 void ConstantPoolCacheEntry::set_vtable_call(Bytecodes::Code invoke_code, const methodHandle& method, int index) {
 332   // either the method is a miranda or its holder should accept the given index
 333   assert(method->method_holder()->is_interface() || method->method_holder()->verify_vtable_index(index), "");
 334   // index >= 0; FIXME: inline and customize set_direct_or_vtable_call
 335   set_direct_or_vtable_call(invoke_code, method, index, false, NULL /* not used */);
 336 }
 337 
 338 void ConstantPoolCacheEntry::set_itable_call(Bytecodes::Code invoke_code,
 339                                              Klass* referenced_klass,
 340                                              const methodHandle& method, int index) {
 341   assert(method->method_holder()->verify_itable_index(index), "");
 342   assert(invoke_code == Bytecodes::_invokeinterface, "");
 343   InstanceKlass* interf = method->method_holder();
 344   assert(interf->is_interface(), "must be an interface");
 345   assert(!method->is_final_method(), "interfaces do not have final methods; cannot link to one here");
 346   set_f1(referenced_klass);
 347   set_f2((intx)method());
 348   set_method_flags(as_TosState(method->result_type()),
 349                    0,  // no option bits
 350                    method()->size_of_parameters());
 351   set_bytecode_1(Bytecodes::_invokeinterface);
 352 }
 353 
 354 
 355 void ConstantPoolCacheEntry::set_method_handle(const constantPoolHandle& cpool, const CallInfo &call_info) {
 356   set_method_handle_common(cpool, Bytecodes::_invokehandle, call_info);
 357 }
 358 
 359 void ConstantPoolCacheEntry::set_dynamic_call(const constantPoolHandle& cpool, const CallInfo &call_info) {
 360   set_method_handle_common(cpool, Bytecodes::_invokedynamic, call_info);
 361 }
 362 
 363 void ConstantPoolCacheEntry::set_method_handle_common(const constantPoolHandle& cpool,
 364                                                       Bytecodes::Code invoke_code,
 365                                                       const CallInfo &call_info) {
 366   // NOTE: This CPCE can be the subject of data races.
 367   // There are three words to update: flags, refs[f2], f1 (in that order).
 368   // Writers must store all other values before f1.
 369   // Readers must test f1 first for non-null before reading other fields.
 370   // Competing writers must acquire exclusive access via a lock.
 371   // A losing writer waits on the lock until the winner writes f1 and leaves
 372   // the lock, so that when the losing writer returns, he can use the linked
 373   // cache entry.
 374 
 375   objArrayHandle resolved_references(Thread::current(), cpool->resolved_references());
 376   // Use the resolved_references() lock for this cpCache entry.
 377   // resolved_references are created for all classes with Invokedynamic, MethodHandle
 378   // or MethodType constant pool cache entries.
 379   assert(resolved_references() != NULL,
 380          "a resolved_references array should have been created for this class");
 381   ObjectLocker ol(resolved_references, Thread::current());
 382   if (!is_f1_null()) {
 383     return;
 384   }
 385 
 386   if (indy_resolution_failed()) {
 387     // Before we got here, another thread got a LinkageError exception during
 388     // resolution.  Ignore our success and throw their exception.
 389     ConstantPoolCache* cpCache = cpool->cache();
 390     int index = -1;
 391     for (int i = 0; i < cpCache->length(); i++) {
 392       if (cpCache->entry_at(i) == this) {
 393         index = i;
 394         break;
 395       }
 396     }
 397     guarantee(index >= 0, "Didn't find cpCache entry!");
 398     int encoded_index = ResolutionErrorTable::encode_cpcache_index(
 399                           ConstantPool::encode_invokedynamic_index(index));
 400     Thread* THREAD = Thread::current();
 401     ConstantPool::throw_resolution_error(cpool, encoded_index, THREAD);
 402     return;
 403   }
 404 
 405   const methodHandle adapter = call_info.resolved_method();
 406   const Handle appendix      = call_info.resolved_appendix();
 407   const bool has_appendix    = appendix.not_null();
 408 
 409   // Write the flags.
 410   // MHs and indy are always sig-poly and have a local signature.
 411   set_method_flags(as_TosState(adapter->result_type()),
 412                    ((has_appendix    ? 1 : 0) << has_appendix_shift        ) |
 413                    (                   1      << has_local_signature_shift ) |
 414                    (                   1      << is_final_shift            ),
 415                    adapter->size_of_parameters());
 416 
 417   if (TraceInvokeDynamic) {
 418     ttyLocker ttyl;
 419     tty->print_cr("set_method_handle bc=%d appendix=" PTR_FORMAT "%s method=" PTR_FORMAT " (local signature) ",
 420                   invoke_code,
 421                   p2i(appendix()),
 422                   (has_appendix ? "" : " (unused)"),
 423                   p2i(adapter()));
 424     adapter->print();
 425     if (has_appendix)  appendix()->print();
 426   }
 427 
 428   // Method handle invokes and invokedynamic sites use both cp cache words.
 429   // refs[f2], if not null, contains a value passed as a trailing argument to the adapter.
 430   // In the general case, this could be the call site's MethodType,
 431   // for use with java.lang.Invokers.checkExactType, or else a CallSite object.
 432   // f1 contains the adapter method which manages the actual call.
 433   // In the general case, this is a compiled LambdaForm.
 434   // (The Java code is free to optimize these calls by binding other
 435   // sorts of methods and appendices to call sites.)
 436   // JVM-level linking is via f1, as if for invokespecial, and signatures are erased.
 437   // The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.
 438   // Even with the appendix, the method will never take more than 255 parameter slots.
 439   //
 440   // This means that given a call site like (List)mh.invoke("foo"),
 441   // the f1 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',
 442   // not '(Ljava/lang/String;)Ljava/util/List;'.
 443   // The fact that String and List are involved is encoded in the MethodType in refs[f2].
 444   // This allows us to create fewer Methods, while keeping type safety.
 445   //
 446 
 447   // Store appendix, if any.
 448   if (has_appendix) {
 449     const int appendix_index = f2_as_index();
 450     assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");
 451     assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
 452     resolved_references->obj_at_put(appendix_index, appendix());
 453   }
 454 
 455   release_set_f1(adapter());  // This must be the last one to set (see NOTE above)!
 456 
 457   // The interpreter assembly code does not check byte_2,
 458   // but it is used by is_resolved, method_if_resolved, etc.
 459   set_bytecode_1(invoke_code);
 460   NOT_PRODUCT(verify(tty));
 461   if (TraceInvokeDynamic) {
 462     ttyLocker ttyl;
 463     this->print(tty, 0);
 464   }
 465 
 466   assert(has_appendix == this->has_appendix(), "proper storage of appendix flag");
 467   assert(this->has_local_signature(), "proper storage of signature flag");
 468 }
 469 
 470 bool ConstantPoolCacheEntry::save_and_throw_indy_exc(
 471   const constantPoolHandle& cpool, int cpool_index, int index, constantTag tag, TRAPS) {
 472 
 473   assert(HAS_PENDING_EXCEPTION, "No exception got thrown!");
 474   assert(PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass()),
 475          "No LinkageError exception");
 476 
 477   // Use the resolved_references() lock for this cpCache entry.
 478   // resolved_references are created for all classes with Invokedynamic, MethodHandle
 479   // or MethodType constant pool cache entries.
 480   objArrayHandle resolved_references(Thread::current(), cpool->resolved_references());
 481   assert(resolved_references() != NULL,
 482          "a resolved_references array should have been created for this class");
 483   ObjectLocker ol(resolved_references, THREAD);
 484 
 485   // if f1 is not null or the indy_resolution_failed flag is set then another
 486   // thread either succeeded in resolving the method or got a LinkageError
 487   // exception, before this thread was able to record its failure.  So, clear
 488   // this thread's exception and return false so caller can use the earlier
 489   // thread's result.
 490   if (!is_f1_null() || indy_resolution_failed()) {
 491     CLEAR_PENDING_EXCEPTION;
 492     return false;
 493   }
 494 
 495   Symbol* error = PENDING_EXCEPTION->klass()->name();
 496   Symbol* message = java_lang_Throwable::detail_message(PENDING_EXCEPTION);
 497 
 498   SystemDictionary::add_resolution_error(cpool, index, error, message);
 499   set_indy_resolution_failed();
 500   return true;
 501 }
 502 
 503 Method* ConstantPoolCacheEntry::method_if_resolved(const constantPoolHandle& cpool) {
 504   // Decode the action of set_method and set_interface_call
 505   Bytecodes::Code invoke_code = bytecode_1();
 506   if (invoke_code != (Bytecodes::Code)0) {
 507     Metadata* f1 = f1_ord();
 508     if (f1 != NULL) {
 509       switch (invoke_code) {
 510       case Bytecodes::_invokeinterface:
 511         assert(f1->is_klass(), "");
 512         return f2_as_interface_method();
 513       case Bytecodes::_invokestatic:
 514       case Bytecodes::_invokespecial:
 515         assert(!has_appendix(), "");
 516       case Bytecodes::_invokehandle:
 517       case Bytecodes::_invokedynamic:
 518         assert(f1->is_method(), "");
 519         return (Method*)f1;
 520       default:
 521         break;
 522       }
 523     }
 524   }
 525   invoke_code = bytecode_2();
 526   if (invoke_code != (Bytecodes::Code)0) {
 527     switch (invoke_code) {
 528     case Bytecodes::_invokevirtual:
 529       if (is_vfinal()) {
 530         // invokevirtual
 531         Method* m = f2_as_vfinal_method();
 532         assert(m->is_method(), "");
 533         return m;
 534       } else {
 535         int holder_index = cpool->uncached_klass_ref_index_at(constant_pool_index());
 536         if (cpool->tag_at(holder_index).is_klass()) {
 537           Klass* klass = cpool->resolved_klass_at(holder_index);
 538           return klass->method_at_vtable(f2_as_index());
 539         }
 540       }
 541       break;
 542     default:
 543       break;
 544     }
 545   }
 546   return NULL;
 547 }
 548 
 549 
 550 oop ConstantPoolCacheEntry::appendix_if_resolved(const constantPoolHandle& cpool) {
 551   if (!has_appendix())
 552     return NULL;
 553   const int ref_index = f2_as_index();
 554   objArrayOop resolved_references = cpool->resolved_references();
 555   return resolved_references->obj_at(ref_index);
 556 }
 557 
 558 
 559 #if INCLUDE_JVMTI
 560 
 561 void log_adjust(const char* entry_type, Method* old_method, Method* new_method, bool* trace_name_printed) {
 562   if (log_is_enabled(Info, redefine, class, update)) {
 563     ResourceMark rm;
 564     if (!(*trace_name_printed)) {
 565       log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
 566       *trace_name_printed = true;
 567     }
 568     log_debug(redefine, class, update, constantpool)
 569           ("cpc %s entry update: %s(%s)", entry_type, new_method->name()->as_C_string(), new_method->signature()->as_C_string());
 570   }
 571 }
 572 
 573 // RedefineClasses() API support:
 574 // If this ConstantPoolCacheEntry refers to old_method then update it
 575 // to refer to new_method.
 576 void ConstantPoolCacheEntry::adjust_method_entry(Method* old_method,
 577        Method* new_method, bool * trace_name_printed) {
 578 
 579   if (is_vfinal()) {
 580     // virtual and final so _f2 contains method ptr instead of vtable index
 581     if (f2_as_vfinal_method() == old_method) {
 582       // match old_method so need an update
 583       // NOTE: can't use set_f2_as_vfinal_method as it asserts on different values
 584       _f2 = (intptr_t)new_method;
 585       log_adjust("vfinal", old_method, new_method, trace_name_printed);
 586     }
 587     return;
 588   }
 589 
 590   assert (_f1 != NULL, "should not call with uninteresting entry");
 591 
 592   if (!(_f1->is_method())) {
 593     // _f1 is a Klass* for an interface, _f2 is the method
 594     if (f2_as_interface_method() == old_method) {
 595       _f2 = (intptr_t)new_method;
 596       log_adjust("interface", old_method, new_method, trace_name_printed);
 597     }
 598   } else if (_f1 == old_method) {
 599     _f1 = new_method;
 600     log_adjust("special, static or dynamic", old_method, new_method, trace_name_printed);
 601   }
 602 }
 603 
 604 // a constant pool cache entry should never contain old or obsolete methods
 605 bool ConstantPoolCacheEntry::check_no_old_or_obsolete_entries() {
 606   Method* m = get_interesting_method_entry();
 607   // return false if m refers to a non-deleted old or obsolete method
 608   if (m != NULL) {
 609     assert(m->is_valid() && m->is_method(), "m is a valid method");
 610     return !m->is_old() && !m->is_obsolete(); // old is always set for old and obsolete
 611   } else {
 612     return true;
 613   }
 614 }
 615 
 616 Method* ConstantPoolCacheEntry::get_interesting_method_entry() {
 617   if (!is_method_entry()) {
 618     // not a method entry so not interesting by default
 619     return NULL;
 620   }
 621   Method* m = NULL;
 622   if (is_vfinal()) {
 623     // virtual and final so _f2 contains method ptr instead of vtable index
 624     m = f2_as_vfinal_method();
 625   } else if (is_f1_null()) {
 626     // NULL _f1 means this is a virtual entry so also not interesting
 627     return NULL;
 628   } else {
 629     if (!(_f1->is_method())) {
 630       // _f1 is a Klass* for an interface
 631       m = f2_as_interface_method();
 632     } else {
 633       m = f1_as_method();
 634     }
 635   }
 636   assert(m != NULL && m->is_method(), "sanity check");
 637   if (m == NULL || !m->is_method()) {
 638     return NULL;
 639   }
 640   return m;
 641 }
 642 #endif // INCLUDE_JVMTI
 643 
 644 void ConstantPoolCacheEntry::print(outputStream* st, int index) const {
 645   // print separator
 646   if (index == 0) st->print_cr("                 -------------");
 647   // print entry
 648   st->print("%3d  (" PTR_FORMAT ")  ", index, (intptr_t)this);
 649   st->print_cr("[%02x|%02x|%5d]", bytecode_2(), bytecode_1(),
 650                constant_pool_index());
 651   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f1);
 652   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f2);
 653   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_flags);
 654   st->print_cr("                 -------------");
 655 }
 656 
 657 void ConstantPoolCacheEntry::verify(outputStream* st) const {
 658   // not implemented yet
 659 }
 660 
 661 // Implementation of ConstantPoolCache
 662 
 663 ConstantPoolCache* ConstantPoolCache::allocate(ClassLoaderData* loader_data,
 664                                      const intStack& index_map,
 665                                      const intStack& invokedynamic_index_map,
 666                                      const intStack& invokedynamic_map, TRAPS) {
 667 
 668   const int length = index_map.length() + invokedynamic_index_map.length();
 669   int size = ConstantPoolCache::size(length);
 670 
 671   return new (loader_data, size, MetaspaceObj::ConstantPoolCacheType, THREAD)
 672     ConstantPoolCache(length, index_map, invokedynamic_index_map, invokedynamic_map);
 673 }
 674 
 675 void ConstantPoolCache::initialize(const intArray& inverse_index_map,
 676                                    const intArray& invokedynamic_inverse_index_map,
 677                                    const intArray& invokedynamic_references_map) {
 678   for (int i = 0; i < inverse_index_map.length(); i++) {
 679     ConstantPoolCacheEntry* e = entry_at(i);
 680     int original_index = inverse_index_map.at(i);
 681     e->initialize_entry(original_index);
 682     assert(entry_at(i) == e, "sanity");
 683   }
 684 
 685   // Append invokedynamic entries at the end
 686   int invokedynamic_offset = inverse_index_map.length();
 687   for (int i = 0; i < invokedynamic_inverse_index_map.length(); i++) {
 688     int offset = i + invokedynamic_offset;
 689     ConstantPoolCacheEntry* e = entry_at(offset);
 690     int original_index = invokedynamic_inverse_index_map.at(i);
 691     e->initialize_entry(original_index);
 692     assert(entry_at(offset) == e, "sanity");
 693   }
 694 
 695   for (int ref = 0; ref < invokedynamic_references_map.length(); ref++) {
 696     const int cpci = invokedynamic_references_map.at(ref);
 697     if (cpci >= 0) {
 698       entry_at(cpci)->initialize_resolved_reference_index(ref);
 699     }
 700   }
 701 }
 702 
 703 void ConstantPoolCache::verify_just_initialized() {
 704   DEBUG_ONLY(walk_entries_for_initialization(/*check_only = */ true));
 705 }
 706 
 707 void ConstantPoolCache::remove_unshareable_info() {
 708   walk_entries_for_initialization(/*check_only = */ false);
 709 }
 710 
 711 void ConstantPoolCache::walk_entries_for_initialization(bool check_only) {
 712   assert(DumpSharedSpaces, "sanity");
 713   // When dumping the archive, we want to clean up the ConstantPoolCache
 714   // to remove any effect of linking due to the execution of Java code --
 715   // each ConstantPoolCacheEntry will have the same contents as if
 716   // ConstantPoolCache::initialize has just returned:
 717   //
 718   // - We keep the ConstantPoolCache::constant_pool_index() bits for all entries.
 719   // - We keep the "f2" field for entries used by invokedynamic and invokehandle
 720   // - All other bits in the entries are cleared to zero.
 721   ResourceMark rm;
 722 
 723   InstanceKlass* ik = constant_pool()->pool_holder();
 724   bool* f2_used = NEW_RESOURCE_ARRAY(bool, length());
 725   memset(f2_used, 0, sizeof(bool) * length());
 726 
 727   // Find all the slots that we need to preserve f2
 728   for (int i = 0; i < ik->methods()->length(); i++) {
 729     Method* m = ik->methods()->at(i);
 730     RawBytecodeStream bcs(m);
 731     while (!bcs.is_last_bytecode()) {
 732       Bytecodes::Code opcode = bcs.raw_next();
 733       switch (opcode) {
 734       case Bytecodes::_invokedynamic: {
 735           int index = Bytes::get_native_u4(bcs.bcp() + 1);
 736           int cp_cache_index = constant_pool()->invokedynamic_cp_cache_index(index);
 737           f2_used[cp_cache_index] = 1;
 738         }
 739         break;
 740       case Bytecodes::_invokehandle: {
 741           int cp_cache_index = Bytes::get_native_u2(bcs.bcp() + 1);
 742           f2_used[cp_cache_index] = 1;
 743         }
 744         break;
 745       default:
 746         break;
 747       }
 748     }
 749   }
 750 
 751   if (check_only) {
 752     DEBUG_ONLY(
 753       for (int i=0; i<length(); i++) {
 754         entry_at(i)->verify_just_initialized(f2_used[i]);
 755       })
 756   } else {
 757     for (int i=0; i<length(); i++) {
 758       entry_at(i)->reinitialize(f2_used[i]);
 759     }
 760   }
 761 }
 762 
 763 void ConstantPoolCache::deallocate_contents(ClassLoaderData* data) {
 764   assert(!is_shared(), "shared caches are not deallocated");
 765   data->remove_handle(_resolved_references);
 766   set_resolved_references(NULL);
 767   MetadataFactory::free_array<u2>(data, _reference_map);
 768   set_reference_map(NULL);
 769 }
 770 
 771 #if INCLUDE_CDS_JAVA_HEAP
 772 oop ConstantPoolCache::archived_references() {
 773   if (CompressedOops::is_null(_archived_references)) {
 774     return NULL;
 775   }
 776   return HeapShared::materialize_archived_object(_archived_references);
 777 }
 778 
 779 void ConstantPoolCache::set_archived_references(oop o) {
 780   assert(DumpSharedSpaces, "called only during runtime");
 781   _archived_references = CompressedOops::encode(o);
 782 }
 783 #endif
 784 
 785 #if INCLUDE_JVMTI
 786 // RedefineClasses() API support:
 787 // If any entry of this ConstantPoolCache points to any of
 788 // old_methods, replace it with the corresponding new_method.
 789 void ConstantPoolCache::adjust_method_entries(bool * trace_name_printed) {
 790   for (int i = 0; i < length(); i++) {
 791     ConstantPoolCacheEntry* entry = entry_at(i);
 792     Method* old_method = entry->get_interesting_method_entry();
 793     if (old_method == NULL || !old_method->is_old()) {
 794       continue; // skip uninteresting entries
 795     }
 796     if (old_method->is_deleted()) {
 797       // clean up entries with deleted methods
 798       entry->initialize_entry(entry->constant_pool_index());
 799       continue;
 800     }
 801     Method* new_method = old_method->get_new_method();
 802     entry_at(i)->adjust_method_entry(old_method, new_method, trace_name_printed);
 803   }
 804 }
 805 
 806 // the constant pool cache should never contain old or obsolete methods
 807 bool ConstantPoolCache::check_no_old_or_obsolete_entries() {
 808   for (int i = 1; i < length(); i++) {
 809     if (entry_at(i)->get_interesting_method_entry() != NULL &&
 810         !entry_at(i)->check_no_old_or_obsolete_entries()) {
 811       return false;
 812     }
 813   }
 814   return true;
 815 }
 816 
 817 void ConstantPoolCache::dump_cache() {
 818   for (int i = 1; i < length(); i++) {
 819     if (entry_at(i)->get_interesting_method_entry() != NULL) {
 820       entry_at(i)->print(tty, i);
 821     }
 822   }
 823 }
 824 #endif // INCLUDE_JVMTI
 825 
 826 void ConstantPoolCache::metaspace_pointers_do(MetaspaceClosure* it) {
 827   log_trace(cds)("Iter(ConstantPoolCache): %p", this);
 828   it->push(&_constant_pool);
 829   it->push(&_reference_map);
 830 }
 831 
 832 // Printing
 833 
 834 void ConstantPoolCache::print_on(outputStream* st) const {
 835   st->print_cr("%s", internal_name());
 836   // print constant pool cache entries
 837   for (int i = 0; i < length(); i++) entry_at(i)->print(st, i);
 838 }
 839 
 840 void ConstantPoolCache::print_value_on(outputStream* st) const {
 841   st->print("cache [%d]", length());
 842   print_address_on(st);
 843   st->print(" for ");
 844   constant_pool()->print_value_on(st);
 845 }
 846 
 847 
 848 // Verification
 849 
 850 void ConstantPoolCache::verify_on(outputStream* st) {
 851   // print constant pool cache entries
 852   for (int i = 0; i < length(); i++) entry_at(i)->verify(st);
 853 }