1 /*
   2  * Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "interpreter/bytecodeStream.hpp"
  27 #include "interpreter/bytecodes.hpp"
  28 #include "interpreter/interpreter.hpp"
  29 #include "interpreter/rewriter.hpp"
  30 #include "logging/log.hpp"
  31 #include "memory/metadataFactory.hpp"
  32 #include "memory/metaspaceClosure.hpp"
  33 #include "memory/resourceArea.hpp"
  34 #include "memory/universe.inline.hpp"
  35 #include "oops/cpCache.hpp"
  36 #include "oops/objArrayOop.inline.hpp"
  37 #include "oops/oop.inline.hpp"
  38 #include "prims/methodHandles.hpp"
  39 #include "runtime/atomic.hpp"
  40 #include "runtime/handles.inline.hpp"
  41 #include "runtime/orderAccess.inline.hpp"
  42 #include "utilities/macros.hpp"
  43 
  44 // Implementation of ConstantPoolCacheEntry
  45 
  46 void ConstantPoolCacheEntry::initialize_entry(int index) {
  47   assert(0 < index && index < 0x10000, "sanity check");
  48   _indices = index;
  49   _f1 = NULL;
  50   _f2 = _flags = 0;
  51   assert(constant_pool_index() == index, "");
  52 }
  53 
  54 void ConstantPoolCacheEntry::verify_just_initialized(bool f2_used) {
  55   assert((_indices & (~cp_index_mask)) == 0, "sanity");
  56   assert(_f1 == NULL, "sanity");
  57   assert(_flags == 0, "sanity");
  58   if (!f2_used) {
  59     assert(_f2 == 0, "sanity");
  60   }
  61 }
  62 
  63 void ConstantPoolCacheEntry::reinitialize(bool f2_used) {
  64   _indices &= cp_index_mask;
  65   _f1 = NULL;
  66   _flags = 0;
  67   if (!f2_used) {
  68     _f2 = 0;
  69   }
  70 }
  71 
  72 int ConstantPoolCacheEntry::make_flags(TosState state,
  73                                        int option_bits,
  74                                        int field_index_or_method_params) {
  75   assert(state < number_of_states, "Invalid state in make_flags");
  76   int f = ((int)state << tos_state_shift) | option_bits | field_index_or_method_params;
  77   // Preserve existing flag bit values
  78   // The low bits are a field offset, or else the method parameter size.
  79 #ifdef ASSERT
  80   TosState old_state = flag_state();
  81   assert(old_state == (TosState)0 || old_state == state,
  82          "inconsistent cpCache flags state");
  83 #endif
  84   return (_flags | f) ;
  85 }
  86 
  87 void ConstantPoolCacheEntry::set_bytecode_1(Bytecodes::Code code) {
  88 #ifdef ASSERT
  89   // Read once.
  90   volatile Bytecodes::Code c = bytecode_1();
  91   assert(c == 0 || c == code || code == 0, "update must be consistent");
  92 #endif
  93   // Need to flush pending stores here before bytecode is written.
  94   OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << bytecode_1_shift));
  95 }
  96 
  97 void ConstantPoolCacheEntry::set_bytecode_2(Bytecodes::Code code) {
  98 #ifdef ASSERT
  99   // Read once.
 100   volatile Bytecodes::Code c = bytecode_2();
 101   assert(c == 0 || c == code || code == 0, "update must be consistent");
 102 #endif
 103   // Need to flush pending stores here before bytecode is written.
 104   OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << bytecode_2_shift));
 105 }
 106 
 107 // Sets f1, ordering with previous writes.
 108 void ConstantPoolCacheEntry::release_set_f1(Metadata* f1) {
 109   assert(f1 != NULL, "");
 110   OrderAccess::release_store_ptr((HeapWord*) &_f1, f1);
 111 }
 112 
 113 // Sets flags, but only if the value was previously zero.
 114 bool ConstantPoolCacheEntry::init_flags_atomic(intptr_t flags) {
 115   intptr_t result = Atomic::cmpxchg_ptr(flags, &_flags, 0);
 116   return (result == 0);
 117 }
 118 
 119 // Note that concurrent update of both bytecodes can leave one of them
 120 // reset to zero.  This is harmless; the interpreter will simply re-resolve
 121 // the damaged entry.  More seriously, the memory synchronization is needed
 122 // to flush other fields (f1, f2) completely to memory before the bytecodes
 123 // are updated, lest other processors see a non-zero bytecode but zero f1/f2.
 124 void ConstantPoolCacheEntry::set_field(Bytecodes::Code get_code,
 125                                        Bytecodes::Code put_code,
 126                                        Klass* field_holder,
 127                                        int field_index,
 128                                        int field_offset,
 129                                        TosState field_type,
 130                                        bool is_final,
 131                                        bool is_volatile,
 132                                        Klass* root_klass) {
 133   set_f1(field_holder);
 134   set_f2(field_offset);
 135   assert((field_index & field_index_mask) == field_index,
 136          "field index does not fit in low flag bits");
 137   set_field_flags(field_type,
 138                   ((is_volatile ? 1 : 0) << is_volatile_shift) |
 139                   ((is_final    ? 1 : 0) << is_final_shift),
 140                   field_index);
 141   set_bytecode_1(get_code);
 142   set_bytecode_2(put_code);
 143   NOT_PRODUCT(verify(tty));
 144 }
 145 
 146 void ConstantPoolCacheEntry::set_parameter_size(int value) {
 147   // This routine is called only in corner cases where the CPCE is not yet initialized.
 148   // See AbstractInterpreter::deopt_continue_after_entry.
 149   assert(_flags == 0 || parameter_size() == 0 || parameter_size() == value,
 150          "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
 151   // Setting the parameter size by itself is only safe if the
 152   // current value of _flags is 0, otherwise another thread may have
 153   // updated it and we don't want to overwrite that value.  Don't
 154   // bother trying to update it once it's nonzero but always make
 155   // sure that the final parameter size agrees with what was passed.
 156   if (_flags == 0) {
 157     Atomic::cmpxchg_ptr((value & parameter_size_mask), &_flags, 0);
 158   }
 159   guarantee(parameter_size() == value,
 160             "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
 161 }
 162 
 163 void ConstantPoolCacheEntry::set_direct_or_vtable_call(Bytecodes::Code invoke_code,
 164                                                        const methodHandle& method,
 165                                                        int vtable_index,
 166                                                        bool sender_is_interface) {
 167   bool is_vtable_call = (vtable_index >= 0);  // FIXME: split this method on this boolean
 168   assert(method->interpreter_entry() != NULL, "should have been set at this point");
 169   assert(!method->is_obsolete(),  "attempt to write obsolete method to cpCache");
 170 
 171   int byte_no = -1;
 172   bool change_to_virtual = false;
 173 
 174   switch (invoke_code) {
 175     case Bytecodes::_invokeinterface:
 176       // We get here from InterpreterRuntime::resolve_invoke when an invokeinterface
 177       // instruction somehow links to a non-interface method (in Object).
 178       // In that case, the method has no itable index and must be invoked as a virtual.
 179       // Set a flag to keep track of this corner case.
 180       change_to_virtual = true;
 181 
 182       // ...and fall through as if we were handling invokevirtual:
 183     case Bytecodes::_invokevirtual:
 184       {
 185         if (!is_vtable_call) {
 186           assert(method->can_be_statically_bound(), "");
 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                            ((change_to_virtual         ? 1 : 0) << is_forced_virtual_shift),
 192                            method()->size_of_parameters());
 193           set_f2_as_vfinal_method(method());
 194         } else {
 195           assert(!method->can_be_statically_bound(), "");
 196           assert(vtable_index >= 0, "valid index");
 197           assert(!method->is_final_method(), "sanity");
 198           set_method_flags(as_TosState(method->result_type()),
 199                            ((change_to_virtual ? 1 : 0) << is_forced_virtual_shift),
 200                            method()->size_of_parameters());
 201           set_f2(vtable_index);
 202         }
 203         byte_no = 2;
 204         break;
 205       }
 206 
 207     case Bytecodes::_invokespecial:
 208     case Bytecodes::_invokestatic:
 209       assert(!is_vtable_call, "");
 210       // Note:  Read and preserve the value of the is_vfinal flag on any
 211       // invokevirtual bytecode shared with this constant pool cache entry.
 212       // It is cheap and safe to consult is_vfinal() at all times.
 213       // Once is_vfinal is set, it must stay that way, lest we get a dangling oop.
 214       set_method_flags(as_TosState(method->result_type()),
 215                        ((is_vfinal()               ? 1 : 0) << is_vfinal_shift) |
 216                        ((method->is_final_method() ? 1 : 0) << is_final_shift),
 217                        method()->size_of_parameters());
 218       set_f1(method());
 219       byte_no = 1;
 220       break;
 221     default:
 222       ShouldNotReachHere();
 223       break;
 224   }
 225 
 226   // Note:  byte_no also appears in TemplateTable::resolve.
 227   if (byte_no == 1) {
 228     assert(invoke_code != Bytecodes::_invokevirtual &&
 229            invoke_code != Bytecodes::_invokeinterface, "");
 230     // Don't mark invokespecial to method as resolved if sender is an interface.  The receiver
 231     // has to be checked that it is a subclass of the current class every time this bytecode
 232     // is executed.
 233     if (invoke_code != Bytecodes::_invokespecial || !sender_is_interface ||
 234         method->name() == vmSymbols::object_initializer_name()) {
 235     set_bytecode_1(invoke_code);
 236     }
 237   } else if (byte_no == 2)  {
 238     if (change_to_virtual) {
 239       assert(invoke_code == Bytecodes::_invokeinterface, "");
 240       // NOTE: THIS IS A HACK - BE VERY CAREFUL!!!
 241       //
 242       // Workaround for the case where we encounter an invokeinterface, but we
 243       // should really have an _invokevirtual since the resolved method is a
 244       // virtual method in java.lang.Object. This is a corner case in the spec
 245       // but is presumably legal. javac does not generate this code.
 246       //
 247       // We set bytecode_1() to _invokeinterface, because that is the
 248       // bytecode # used by the interpreter to see if it is resolved.
 249       // We set bytecode_2() to _invokevirtual.
 250       // See also interpreterRuntime.cpp. (8/25/2000)
 251       // Only set resolved for the invokeinterface case if method is public.
 252       // Otherwise, the method needs to be reresolved with caller for each
 253       // interface call.
 254       if (method->is_public()) set_bytecode_1(invoke_code);
 255     } else {
 256       assert(invoke_code == Bytecodes::_invokevirtual, "");
 257     }
 258     // set up for invokevirtual, even if linking for invokeinterface also:
 259     set_bytecode_2(Bytecodes::_invokevirtual);
 260   } else {
 261     ShouldNotReachHere();
 262   }
 263   NOT_PRODUCT(verify(tty));
 264 }
 265 
 266 void ConstantPoolCacheEntry::set_direct_call(Bytecodes::Code invoke_code, const methodHandle& method,
 267                                              bool sender_is_interface) {
 268   int index = Method::nonvirtual_vtable_index;
 269   // index < 0; FIXME: inline and customize set_direct_or_vtable_call
 270   set_direct_or_vtable_call(invoke_code, method, index, sender_is_interface);
 271 }
 272 
 273 void ConstantPoolCacheEntry::set_vtable_call(Bytecodes::Code invoke_code, const methodHandle& method, int index) {
 274   // either the method is a miranda or its holder should accept the given index
 275   assert(method->method_holder()->is_interface() || method->method_holder()->verify_vtable_index(index), "");
 276   // index >= 0; FIXME: inline and customize set_direct_or_vtable_call
 277   set_direct_or_vtable_call(invoke_code, method, index, false);
 278 }
 279 
 280 void ConstantPoolCacheEntry::set_itable_call(Bytecodes::Code invoke_code, const methodHandle& method, int index) {
 281   assert(method->method_holder()->verify_itable_index(index), "");
 282   assert(invoke_code == Bytecodes::_invokeinterface, "");
 283   InstanceKlass* interf = method->method_holder();
 284   assert(interf->is_interface(), "must be an interface");
 285   assert(!method->is_final_method(), "interfaces do not have final methods; cannot link to one here");
 286   set_f1(interf);
 287   set_f2(index);
 288   set_method_flags(as_TosState(method->result_type()),
 289                    0,  // no option bits
 290                    method()->size_of_parameters());
 291   set_bytecode_1(Bytecodes::_invokeinterface);
 292 }
 293 
 294 
 295 void ConstantPoolCacheEntry::set_method_handle(const constantPoolHandle& cpool, const CallInfo &call_info) {
 296   set_method_handle_common(cpool, Bytecodes::_invokehandle, call_info);
 297 }
 298 
 299 void ConstantPoolCacheEntry::set_dynamic_call(const constantPoolHandle& cpool, const CallInfo &call_info) {
 300   set_method_handle_common(cpool, Bytecodes::_invokedynamic, call_info);
 301 }
 302 
 303 void ConstantPoolCacheEntry::set_method_handle_common(const constantPoolHandle& cpool,
 304                                                       Bytecodes::Code invoke_code,
 305                                                       const CallInfo &call_info) {
 306   // NOTE: This CPCE can be the subject of data races.
 307   // There are three words to update: flags, refs[f2], f1 (in that order).
 308   // Writers must store all other values before f1.
 309   // Readers must test f1 first for non-null before reading other fields.
 310   // Competing writers must acquire exclusive access via a lock.
 311   // A losing writer waits on the lock until the winner writes f1 and leaves
 312   // the lock, so that when the losing writer returns, he can use the linked
 313   // cache entry.
 314 
 315   objArrayHandle resolved_references(Thread::current(), cpool->resolved_references());
 316   // Use the resolved_references() lock for this cpCache entry.
 317   // resolved_references are created for all classes with Invokedynamic, MethodHandle
 318   // or MethodType constant pool cache entries.
 319   assert(resolved_references() != NULL,
 320          "a resolved_references array should have been created for this class");
 321   ObjectLocker ol(resolved_references, Thread::current());
 322   if (!is_f1_null()) {
 323     return;
 324   }
 325 
 326   const methodHandle adapter = call_info.resolved_method();
 327   const Handle appendix      = call_info.resolved_appendix();
 328   const Handle method_type   = call_info.resolved_method_type();
 329   const bool has_appendix    = appendix.not_null();
 330   const bool has_method_type = method_type.not_null();
 331 
 332   // Write the flags.
 333   set_method_flags(as_TosState(adapter->result_type()),
 334                    ((has_appendix    ? 1 : 0) << has_appendix_shift   ) |
 335                    ((has_method_type ? 1 : 0) << has_method_type_shift) |
 336                    (                   1      << is_final_shift       ),
 337                    adapter->size_of_parameters());
 338 
 339   if (TraceInvokeDynamic) {
 340     ttyLocker ttyl;
 341     tty->print_cr("set_method_handle bc=%d appendix=" PTR_FORMAT "%s method_type=" PTR_FORMAT "%s method=" PTR_FORMAT " ",
 342                   invoke_code,
 343                   p2i(appendix()),    (has_appendix    ? "" : " (unused)"),
 344                   p2i(method_type()), (has_method_type ? "" : " (unused)"),
 345                   p2i(adapter()));
 346     adapter->print();
 347     if (has_appendix)  appendix()->print();
 348   }
 349 
 350   // Method handle invokes and invokedynamic sites use both cp cache words.
 351   // refs[f2], if not null, contains a value passed as a trailing argument to the adapter.
 352   // In the general case, this could be the call site's MethodType,
 353   // for use with java.lang.Invokers.checkExactType, or else a CallSite object.
 354   // f1 contains the adapter method which manages the actual call.
 355   // In the general case, this is a compiled LambdaForm.
 356   // (The Java code is free to optimize these calls by binding other
 357   // sorts of methods and appendices to call sites.)
 358   // JVM-level linking is via f1, as if for invokespecial, and signatures are erased.
 359   // The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.
 360   // Even with the appendix, the method will never take more than 255 parameter slots.
 361   //
 362   // This means that given a call site like (List)mh.invoke("foo"),
 363   // the f1 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',
 364   // not '(Ljava/lang/String;)Ljava/util/List;'.
 365   // The fact that String and List are involved is encoded in the MethodType in refs[f2].
 366   // This allows us to create fewer Methods, while keeping type safety.
 367   //
 368 
 369   // Store appendix, if any.
 370   if (has_appendix) {
 371     const int appendix_index = f2_as_index() + _indy_resolved_references_appendix_offset;
 372     assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");
 373     assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
 374     resolved_references->obj_at_put(appendix_index, appendix());
 375   }
 376 
 377   // Store MethodType, if any.
 378   if (has_method_type) {
 379     const int method_type_index = f2_as_index() + _indy_resolved_references_method_type_offset;
 380     assert(method_type_index >= 0 && method_type_index < resolved_references->length(), "oob");
 381     assert(resolved_references->obj_at(method_type_index) == NULL, "init just once");
 382     resolved_references->obj_at_put(method_type_index, method_type());
 383   }
 384 
 385   release_set_f1(adapter());  // This must be the last one to set (see NOTE above)!
 386 
 387   // The interpreter assembly code does not check byte_2,
 388   // but it is used by is_resolved, method_if_resolved, etc.
 389   set_bytecode_1(invoke_code);
 390   NOT_PRODUCT(verify(tty));
 391   if (TraceInvokeDynamic) {
 392     ttyLocker ttyl;
 393     this->print(tty, 0);
 394   }
 395 }
 396 
 397 Method* ConstantPoolCacheEntry::method_if_resolved(const constantPoolHandle& cpool) {
 398   // Decode the action of set_method and set_interface_call
 399   Bytecodes::Code invoke_code = bytecode_1();
 400   if (invoke_code != (Bytecodes::Code)0) {
 401     Metadata* f1 = f1_ord();
 402     if (f1 != NULL) {
 403       switch (invoke_code) {
 404       case Bytecodes::_invokeinterface:
 405         assert(f1->is_klass(), "");
 406         return klassItable::method_for_itable_index((Klass*)f1, f2_as_index());
 407       case Bytecodes::_invokestatic:
 408       case Bytecodes::_invokespecial:
 409         assert(!has_appendix(), "");
 410       case Bytecodes::_invokehandle:
 411       case Bytecodes::_invokedynamic:
 412         assert(f1->is_method(), "");
 413         return (Method*)f1;
 414       default:
 415         break;
 416       }
 417     }
 418   }
 419   invoke_code = bytecode_2();
 420   if (invoke_code != (Bytecodes::Code)0) {
 421     switch (invoke_code) {
 422     case Bytecodes::_invokevirtual:
 423       if (is_vfinal()) {
 424         // invokevirtual
 425         Method* m = f2_as_vfinal_method();
 426         assert(m->is_method(), "");
 427         return m;
 428       } else {
 429         int holder_index = cpool->uncached_klass_ref_index_at(constant_pool_index());
 430         if (cpool->tag_at(holder_index).is_klass()) {
 431           Klass* klass = cpool->resolved_klass_at(holder_index);
 432           return klass->method_at_vtable(f2_as_index());
 433         }
 434       }
 435       break;
 436     default:
 437       break;
 438     }
 439   }
 440   return NULL;
 441 }
 442 
 443 
 444 oop ConstantPoolCacheEntry::appendix_if_resolved(const constantPoolHandle& cpool) {
 445   if (!has_appendix())
 446     return NULL;
 447   const int ref_index = f2_as_index() + _indy_resolved_references_appendix_offset;
 448   objArrayOop resolved_references = cpool->resolved_references();
 449   return resolved_references->obj_at(ref_index);
 450 }
 451 
 452 
 453 oop ConstantPoolCacheEntry::method_type_if_resolved(const constantPoolHandle& cpool) {
 454   if (!has_method_type())
 455     return NULL;
 456   const int ref_index = f2_as_index() + _indy_resolved_references_method_type_offset;
 457   objArrayOop resolved_references = cpool->resolved_references();
 458   return resolved_references->obj_at(ref_index);
 459 }
 460 
 461 
 462 #if INCLUDE_JVMTI
 463 // RedefineClasses() API support:
 464 // If this ConstantPoolCacheEntry refers to old_method then update it
 465 // to refer to new_method.
 466 bool ConstantPoolCacheEntry::adjust_method_entry(Method* old_method,
 467        Method* new_method, bool * trace_name_printed) {
 468 
 469   if (is_vfinal()) {
 470     // virtual and final so _f2 contains method ptr instead of vtable index
 471     if (f2_as_vfinal_method() == old_method) {
 472       // match old_method so need an update
 473       // NOTE: can't use set_f2_as_vfinal_method as it asserts on different values
 474       _f2 = (intptr_t)new_method;
 475       if (log_is_enabled(Info, redefine, class, update)) {
 476         ResourceMark rm;
 477         if (!(*trace_name_printed)) {
 478           log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
 479           *trace_name_printed = true;
 480         }
 481         log_debug(redefine, class, update, constantpool)
 482           ("cpc vf-entry update: %s(%s)", new_method->name()->as_C_string(), new_method->signature()->as_C_string());
 483       }
 484       return true;
 485     }
 486 
 487     // f1() is not used with virtual entries so bail out
 488     return false;
 489   }
 490 
 491   if (_f1 == NULL) {
 492     // NULL f1() means this is a virtual entry so bail out
 493     // We are assuming that the vtable index does not need change.
 494     return false;
 495   }
 496 
 497   if (_f1 == old_method) {
 498     _f1 = new_method;
 499     if (log_is_enabled(Info, redefine, class, update)) {
 500       ResourceMark rm;
 501       if (!(*trace_name_printed)) {
 502         log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
 503         *trace_name_printed = true;
 504       }
 505       log_debug(redefine, class, update, constantpool)
 506         ("cpc entry update: %s(%s)", new_method->name()->as_C_string(), new_method->signature()->as_C_string());
 507     }
 508     return true;
 509   }
 510 
 511   return false;
 512 }
 513 
 514 // a constant pool cache entry should never contain old or obsolete methods
 515 bool ConstantPoolCacheEntry::check_no_old_or_obsolete_entries() {
 516   if (is_vfinal()) {
 517     // virtual and final so _f2 contains method ptr instead of vtable index
 518     Metadata* f2 = (Metadata*)_f2;
 519     // Return false if _f2 refers to an old or an obsolete method.
 520     // _f2 == NULL || !_f2->is_method() are just as unexpected here.
 521     return (f2 != NULL NOT_PRODUCT(&& f2->is_valid()) && f2->is_method() &&
 522             !((Method*)f2)->is_old() && !((Method*)f2)->is_obsolete());
 523   } else if (_f1 == NULL ||
 524              (NOT_PRODUCT(_f1->is_valid() &&) !_f1->is_method())) {
 525     // _f1 == NULL || !_f1->is_method() are OK here
 526     return true;
 527   }
 528   // return false if _f1 refers to a non-deleted old or obsolete method
 529   return (NOT_PRODUCT(_f1->is_valid() &&) _f1->is_method() &&
 530           (f1_as_method()->is_deleted() ||
 531           (!f1_as_method()->is_old() && !f1_as_method()->is_obsolete())));
 532 }
 533 
 534 Method* ConstantPoolCacheEntry::get_interesting_method_entry(Klass* k) {
 535   if (!is_method_entry()) {
 536     // not a method entry so not interesting by default
 537     return NULL;
 538   }
 539   Method* m = NULL;
 540   if (is_vfinal()) {
 541     // virtual and final so _f2 contains method ptr instead of vtable index
 542     m = f2_as_vfinal_method();
 543   } else if (is_f1_null()) {
 544     // NULL _f1 means this is a virtual entry so also not interesting
 545     return NULL;
 546   } else {
 547     if (!(_f1->is_method())) {
 548       // _f1 can also contain a Klass* for an interface
 549       return NULL;
 550     }
 551     m = f1_as_method();
 552   }
 553   assert(m != NULL && m->is_method(), "sanity check");
 554   if (m == NULL || !m->is_method() || (k != NULL && m->method_holder() != k)) {
 555     // robustness for above sanity checks or method is not in
 556     // the interesting class
 557     return NULL;
 558   }
 559   // the method is in the interesting class so the entry is interesting
 560   return m;
 561 }
 562 #endif // INCLUDE_JVMTI
 563 
 564 void ConstantPoolCacheEntry::print(outputStream* st, int index) const {
 565   // print separator
 566   if (index == 0) st->print_cr("                 -------------");
 567   // print entry
 568   st->print("%3d  (" PTR_FORMAT ")  ", index, (intptr_t)this);
 569   st->print_cr("[%02x|%02x|%5d]", bytecode_2(), bytecode_1(),
 570                constant_pool_index());
 571   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f1);
 572   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f2);
 573   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_flags);
 574   st->print_cr("                 -------------");
 575 }
 576 
 577 void ConstantPoolCacheEntry::verify(outputStream* st) const {
 578   // not implemented yet
 579 }
 580 
 581 // Implementation of ConstantPoolCache
 582 
 583 ConstantPoolCache* ConstantPoolCache::allocate(ClassLoaderData* loader_data,
 584                                      const intStack& index_map,
 585                                      const intStack& invokedynamic_index_map,
 586                                      const intStack& invokedynamic_map, TRAPS) {
 587 
 588   const int length = index_map.length() + invokedynamic_index_map.length();
 589   int size = ConstantPoolCache::size(length);
 590 
 591   return new (loader_data, size, MetaspaceObj::ConstantPoolCacheType, THREAD)
 592     ConstantPoolCache(length, index_map, invokedynamic_index_map, invokedynamic_map);
 593 }
 594 
 595 void ConstantPoolCache::initialize(const intArray& inverse_index_map,
 596                                    const intArray& invokedynamic_inverse_index_map,
 597                                    const intArray& invokedynamic_references_map) {
 598   for (int i = 0; i < inverse_index_map.length(); i++) {
 599     ConstantPoolCacheEntry* e = entry_at(i);
 600     int original_index = inverse_index_map.at(i);
 601     e->initialize_entry(original_index);
 602     assert(entry_at(i) == e, "sanity");
 603   }
 604 
 605   // Append invokedynamic entries at the end
 606   int invokedynamic_offset = inverse_index_map.length();
 607   for (int i = 0; i < invokedynamic_inverse_index_map.length(); i++) {
 608     int offset = i + invokedynamic_offset;
 609     ConstantPoolCacheEntry* e = entry_at(offset);
 610     int original_index = invokedynamic_inverse_index_map.at(i);
 611     e->initialize_entry(original_index);
 612     assert(entry_at(offset) == e, "sanity");
 613   }
 614 
 615   for (int ref = 0; ref < invokedynamic_references_map.length(); ref++) {
 616     const int cpci = invokedynamic_references_map.at(ref);
 617     if (cpci >= 0) {
 618 #ifdef ASSERT
 619       // invokedynamic and invokehandle have more entries; check if they
 620       // all point to the same constant pool cache entry.
 621       for (int entry = 1; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {
 622         const int cpci_next = invokedynamic_references_map.at(ref + entry);
 623         assert(cpci == cpci_next, "%d == %d", cpci, cpci_next);
 624       }
 625 #endif
 626       entry_at(cpci)->initialize_resolved_reference_index(ref);
 627       ref += ConstantPoolCacheEntry::_indy_resolved_references_entries - 1;  // skip extra entries
 628     }
 629   }
 630 }
 631 
 632 void ConstantPoolCache::verify_just_initialized() {
 633   DEBUG_ONLY(walk_entries_for_initialization(/*check_only = */ true));
 634 }
 635 
 636 void ConstantPoolCache::remove_unshareable_info() {
 637   walk_entries_for_initialization(/*check_only = */ false);
 638 }
 639 
 640 void ConstantPoolCache::walk_entries_for_initialization(bool check_only) {
 641   assert(DumpSharedSpaces, "sanity");
 642   // When dumping the archive, we want to clean up the ConstantPoolCache
 643   // to remove any effect of linking due to the execution of Java code --
 644   // each ConstantPoolCacheEntry will have the same contents as if
 645   // ConstantPoolCache::initialize has just returned:
 646   //
 647   // - We keep the ConstantPoolCache::constant_pool_index() bits for all entries.
 648   // - We keep the "f2" field for entries used by invokedynamic and invokehandle
 649   // - All other bits in the entries are cleared to zero.
 650   ResourceMark rm;
 651 
 652   InstanceKlass* ik = constant_pool()->pool_holder();
 653   bool* f2_used = NEW_RESOURCE_ARRAY(bool, length());
 654   memset(f2_used, 0, sizeof(bool) * length());
 655 
 656   // Find all the slots that we need to preserve f2
 657   for (int i = 0; i < ik->methods()->length(); i++) {
 658     Method* m = ik->methods()->at(i);
 659     RawBytecodeStream bcs(m);
 660     while (!bcs.is_last_bytecode()) {
 661       Bytecodes::Code opcode = bcs.raw_next();
 662       switch (opcode) {
 663       case Bytecodes::_invokedynamic: {
 664           int index = Bytes::get_native_u4(bcs.bcp() + 1);
 665           int cp_cache_index = constant_pool()->invokedynamic_cp_cache_index(index);
 666           f2_used[cp_cache_index] = 1;
 667         }
 668         break;
 669       case Bytecodes::_invokehandle: {
 670           int cp_cache_index = Bytes::get_native_u2(bcs.bcp() + 1);
 671           f2_used[cp_cache_index] = 1;
 672         }
 673         break;
 674       default:
 675         break;
 676       }
 677     }
 678   }
 679 
 680   if (check_only) {
 681     DEBUG_ONLY(
 682       for (int i=0; i<length(); i++) {
 683         entry_at(i)->verify_just_initialized(f2_used[i]);
 684       })
 685   } else {
 686     for (int i=0; i<length(); i++) {
 687       entry_at(i)->reinitialize(f2_used[i]);
 688     }
 689   }
 690 }
 691 
 692 void ConstantPoolCache::deallocate_contents(ClassLoaderData* data) {
 693   assert(!is_shared(), "shared caches are not deallocated");
 694   data->remove_handle(_resolved_references);
 695   set_resolved_references(NULL);
 696   MetadataFactory::free_array<u2>(data, _reference_map);
 697   set_reference_map(NULL);
 698 }
 699 
 700 #if INCLUDE_CDS_JAVA_HEAP
 701 oop ConstantPoolCache::archived_references() {
 702   assert(UseSharedSpaces, "UseSharedSpaces expected.");
 703   return oopDesc::decode_heap_oop(_archived_references);
 704 }
 705 
 706 void ConstantPoolCache::set_archived_references(oop o) {
 707   assert(DumpSharedSpaces, "called only during runtime");
 708   _archived_references = oopDesc::encode_heap_oop(o);
 709 }
 710 #endif
 711 
 712 #if INCLUDE_JVMTI
 713 // RedefineClasses() API support:
 714 // If any entry of this ConstantPoolCache points to any of
 715 // old_methods, replace it with the corresponding new_method.
 716 void ConstantPoolCache::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
 717   for (int i = 0; i < length(); i++) {
 718     ConstantPoolCacheEntry* entry = entry_at(i);
 719     Method* old_method = entry->get_interesting_method_entry(holder);
 720     if (old_method == NULL || !old_method->is_old()) {
 721       continue; // skip uninteresting entries
 722     }
 723     if (old_method->is_deleted()) {
 724       // clean up entries with deleted methods
 725       entry->initialize_entry(entry->constant_pool_index());
 726       continue;
 727     }
 728     Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
 729 
 730     assert(new_method != NULL, "method_with_idnum() should not be NULL");
 731     assert(old_method != new_method, "sanity check");
 732 
 733     entry_at(i)->adjust_method_entry(old_method, new_method, trace_name_printed);
 734   }
 735 }
 736 
 737 // the constant pool cache should never contain old or obsolete methods
 738 bool ConstantPoolCache::check_no_old_or_obsolete_entries() {
 739   for (int i = 1; i < length(); i++) {
 740     if (entry_at(i)->get_interesting_method_entry(NULL) != NULL &&
 741         !entry_at(i)->check_no_old_or_obsolete_entries()) {
 742       return false;
 743     }
 744   }
 745   return true;
 746 }
 747 
 748 void ConstantPoolCache::dump_cache() {
 749   for (int i = 1; i < length(); i++) {
 750     if (entry_at(i)->get_interesting_method_entry(NULL) != NULL) {
 751       entry_at(i)->print(tty, i);
 752     }
 753   }
 754 }
 755 #endif // INCLUDE_JVMTI
 756 
 757 void ConstantPoolCache::metaspace_pointers_do(MetaspaceClosure* it) {
 758   log_trace(cds)("Iter(ConstantPoolCache): %p", this);
 759   it->push(&_constant_pool);
 760   it->push(&_reference_map);
 761 }
 762 
 763 // Printing
 764 
 765 void ConstantPoolCache::print_on(outputStream* st) const {
 766   assert(is_constantPoolCache(), "obj must be constant pool cache");
 767   st->print_cr("%s", internal_name());
 768   // print constant pool cache entries
 769   for (int i = 0; i < length(); i++) entry_at(i)->print(st, i);
 770 }
 771 
 772 void ConstantPoolCache::print_value_on(outputStream* st) const {
 773   assert(is_constantPoolCache(), "obj must be constant pool cache");
 774   st->print("cache [%d]", length());
 775   print_address_on(st);
 776   st->print(" for ");
 777   constant_pool()->print_value_on(st);
 778 }
 779 
 780 
 781 // Verification
 782 
 783 void ConstantPoolCache::verify_on(outputStream* st) {
 784   guarantee(is_constantPoolCache(), "obj must be constant pool cache");
 785   // print constant pool cache entries
 786   for (int i = 0; i < length(); i++) entry_at(i)->verify(st);
 787 }