1 /*
  2  * Copyright (c) 1998, 2020, 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 "logging/logStream.hpp"
 34 #include "memory/heapShared.hpp"
 35 #include "memory/metadataFactory.hpp"
 36 #include "memory/metaspaceClosure.hpp"
 37 #include "memory/metaspaceShared.hpp"
 38 #include "memory/resourceArea.hpp"
 39 #include "oops/access.inline.hpp"
 40 #include "oops/compressedOops.hpp"
 41 #include "oops/constantPool.inline.hpp"
 42 #include "oops/cpCache.inline.hpp"
 43 #include "oops/objArrayOop.inline.hpp"
 44 #include "oops/oop.inline.hpp"
 45 #include "prims/methodHandles.hpp"
 46 #include "runtime/arguments.hpp"
 47 #include "runtime/atomic.hpp"
 48 #include "runtime/handles.inline.hpp"
 49 #include "utilities/macros.hpp"
 50 
 51 // Implementation of ConstantPoolCacheEntry
 52 
 53 void ConstantPoolCacheEntry::initialize_entry(int index) {
 54   assert(0 < index && index < 0x10000, "sanity check");
 55   _indices = index;
 56   _f1 = NULL;
 57   _f2 = _flags = 0;
 58   assert(constant_pool_index() == index, "");
 59 }
 60 
 61 void ConstantPoolCacheEntry::verify_just_initialized(bool f2_used) {
 62   assert((_indices & (~cp_index_mask)) == 0, "sanity");
 63   assert(_f1 == NULL, "sanity");
 64   assert(_flags == 0, "sanity");
 65   if (!f2_used) {
 66     assert(_f2 == 0, "sanity");
 67   }
 68 }
 69 
 70 void ConstantPoolCacheEntry::reinitialize(bool f2_used) {
 71   _indices &= cp_index_mask;
 72   _f1 = NULL;
 73   _flags = 0;
 74   if (!f2_used) {
 75     _f2 = 0;
 76   }
 77 }
 78 
 79 int ConstantPoolCacheEntry::make_flags(TosState state,
 80                                        int option_bits,
 81                                        int field_index_or_method_params) {
 82   assert(state < number_of_states, "Invalid state in make_flags");
 83   int f = ((int)state << tos_state_shift) | option_bits | field_index_or_method_params;
 84   // Preserve existing flag bit values
 85   // The low bits are a field offset, or else the method parameter size.
 86 #ifdef ASSERT
 87   TosState old_state = flag_state();
 88   assert(old_state == (TosState)0 || old_state == state,
 89          "inconsistent cpCache flags state");
 90 #endif
 91   return (_flags | f) ;
 92 }
 93 
 94 void ConstantPoolCacheEntry::set_bytecode_1(Bytecodes::Code code) {
 95 #ifdef ASSERT
 96   // Read once.
 97   volatile Bytecodes::Code c = bytecode_1();
 98   assert(c == 0 || c == code || code == 0, "update must be consistent");
 99 #endif
100   // Need to flush pending stores here before bytecode is written.
101   Atomic::release_store(&_indices, _indices | ((u_char)code << bytecode_1_shift));
102 }
103 
104 void ConstantPoolCacheEntry::set_bytecode_2(Bytecodes::Code code) {
105 #ifdef ASSERT
106   // Read once.
107   volatile Bytecodes::Code c = bytecode_2();
108   assert(c == 0 || c == code || code == 0, "update must be consistent");
109 #endif
110   // Need to flush pending stores here before bytecode is written.
111   Atomic::release_store(&_indices, _indices | ((u_char)code << bytecode_2_shift));
112 }
113 
114 // Sets f1, ordering with previous writes.
115 void ConstantPoolCacheEntry::release_set_f1(Metadata* f1) {
116   assert(f1 != NULL, "");
117   Atomic::release_store(&_f1, f1);
118 }
119 
120 void ConstantPoolCacheEntry::set_indy_resolution_failed() {
121   Atomic::release_store(&_flags, _flags | (1 << indy_resolution_failed_shift));
122 }
123 
124 // Note that concurrent update of both bytecodes can leave one of them
125 // reset to zero.  This is harmless; the interpreter will simply re-resolve
126 // the damaged entry.  More seriously, the memory synchronization is needed
127 // to flush other fields (f1, f2) completely to memory before the bytecodes
128 // are updated, lest other processors see a non-zero bytecode but zero f1/f2.
129 void ConstantPoolCacheEntry::set_field(Bytecodes::Code get_code,
130                                        Bytecodes::Code put_code,
131                                        Klass* field_holder,
132                                        int field_index,
133                                        int field_offset,
134                                        TosState field_type,
135                                        bool is_final,
136                                        bool is_volatile,
137                                        Klass* root_klass) {
138   set_f1(field_holder);
139   set_f2(field_offset);
140   assert((field_index & field_index_mask) == field_index,
141          "field index does not fit in low flag bits");
142   set_field_flags(field_type,
143                   ((is_volatile ? 1 : 0) << is_volatile_shift) |
144                   ((is_final    ? 1 : 0) << is_final_shift),
145                   field_index);
146   set_bytecode_1(get_code);
147   set_bytecode_2(put_code);
148   NOT_PRODUCT(verify(tty));
149 }
150 
151 void ConstantPoolCacheEntry::set_parameter_size(int value) {
152   // This routine is called only in corner cases where the CPCE is not yet initialized.
153   // See AbstractInterpreter::deopt_continue_after_entry.
154   assert(_flags == 0 || parameter_size() == 0 || parameter_size() == value,
155          "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
156   // Setting the parameter size by itself is only safe if the
157   // current value of _flags is 0, otherwise another thread may have
158   // updated it and we don't want to overwrite that value.  Don't
159   // bother trying to update it once it's nonzero but always make
160   // sure that the final parameter size agrees with what was passed.
161   if (_flags == 0) {
162     intx newflags = (value & parameter_size_mask);
163     Atomic::cmpxchg(&_flags, (intx)0, newflags);
164   }
165   guarantee(parameter_size() == value,
166             "size must not change: parameter_size=%d, value=%d", parameter_size(), value);
167 }
168 
169 void ConstantPoolCacheEntry::set_direct_or_vtable_call(Bytecodes::Code invoke_code,
170                                                        const methodHandle& method,
171                                                        int vtable_index,
172                                                        bool sender_is_interface) {
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       assert(method->method_holder()->is_initialized() ||
267              method->method_holder()->is_reentrant_initialization(Thread::current()),
268              "invalid class initialization state for invoke_static");
269 
270       if (!VM_Version::supports_fast_class_init_checks() && method->needs_clinit_barrier()) {
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         //
275         // When fast class initialization checks are supported (VM_Version::supports_fast_class_init_checks() == true),
276         // template interpreter supports fast class initialization check for
277         // invokestatic which doesn't require call site re-resolution to
278         // enforce class initialization barrier.
279         do_resolve = false;
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) {
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);
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);
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   Method* 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   LogStream* log_stream = NULL;
418   LogStreamHandle(Debug, methodhandles, indy) lsh_indy;
419   if (lsh_indy.is_enabled()) {
420     ResourceMark rm;
421     log_stream = &lsh_indy;
422     log_stream->print_cr("set_method_handle bc=%d appendix=" PTR_FORMAT "%s method=" PTR_FORMAT " (local signature) ",
423                          invoke_code,
424                          p2i(appendix()),
425                          (has_appendix ? "" : " (unused)"),
426                          p2i(adapter));
427     adapter->print_on(log_stream);
428     if (has_appendix)  appendix()->print_on(log_stream);
429   }
430 
431   // Method handle invokes and invokedynamic sites use both cp cache words.
432   // refs[f2], if not null, contains a value passed as a trailing argument to the adapter.
433   // In the general case, this could be the call site's MethodType,
434   // for use with java.lang.Invokers.checkExactType, or else a CallSite object.
435   // f1 contains the adapter method which manages the actual call.
436   // In the general case, this is a compiled LambdaForm.
437   // (The Java code is free to optimize these calls by binding other
438   // sorts of methods and appendices to call sites.)
439   // JVM-level linking is via f1, as if for invokespecial, and signatures are erased.
440   // The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.
441   // Even with the appendix, the method will never take more than 255 parameter slots.
442   //
443   // This means that given a call site like (List)mh.invoke("foo"),
444   // the f1 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',
445   // not '(Ljava/lang/String;)Ljava/util/List;'.
446   // The fact that String and List are involved is encoded in the MethodType in refs[f2].
447   // This allows us to create fewer Methods, while keeping type safety.
448   //
449 
450   // Store appendix, if any.
451   if (has_appendix) {
452     const int appendix_index = f2_as_index();
453     assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");
454     assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
455     resolved_references->obj_at_put(appendix_index, appendix());
456   }
457 
458   release_set_f1(adapter);  // This must be the last one to set (see NOTE above)!
459 
460   // The interpreter assembly code does not check byte_2,
461   // but it is used by is_resolved, method_if_resolved, etc.
462   set_bytecode_1(invoke_code);
463   NOT_PRODUCT(verify(tty));
464 
465   if (log_stream != NULL) {
466     this->print(log_stream, 0);
467   }
468 
469   assert(has_appendix == this->has_appendix(), "proper storage of appendix flag");
470   assert(this->has_local_signature(), "proper storage of signature flag");
471 }
472 
473 bool ConstantPoolCacheEntry::save_and_throw_indy_exc(
474   const constantPoolHandle& cpool, int cpool_index, int index, constantTag tag, TRAPS) {
475 
476   assert(HAS_PENDING_EXCEPTION, "No exception got thrown!");
477   assert(PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass()),
478          "No LinkageError exception");
479 
480   // Use the resolved_references() lock for this cpCache entry.
481   // resolved_references are created for all classes with Invokedynamic, MethodHandle
482   // or MethodType constant pool cache entries.
483   objArrayHandle resolved_references(Thread::current(), cpool->resolved_references());
484   assert(resolved_references() != NULL,
485          "a resolved_references array should have been created for this class");
486   ObjectLocker ol(resolved_references, THREAD);
487 
488   // if f1 is not null or the indy_resolution_failed flag is set then another
489   // thread either succeeded in resolving the method or got a LinkageError
490   // exception, before this thread was able to record its failure.  So, clear
491   // this thread's exception and return false so caller can use the earlier
492   // thread's result.
493   if (!is_f1_null() || indy_resolution_failed()) {
494     CLEAR_PENDING_EXCEPTION;
495     return false;
496   }
497 
498   Symbol* error = PENDING_EXCEPTION->klass()->name();
499   Symbol* message = java_lang_Throwable::detail_message(PENDING_EXCEPTION);
500 
501   SystemDictionary::add_resolution_error(cpool, index, error, message);
502   set_indy_resolution_failed();
503   return true;
504 }
505 
506 Method* ConstantPoolCacheEntry::method_if_resolved(const constantPoolHandle& cpool) {
507   // Decode the action of set_method and set_interface_call
508   Bytecodes::Code invoke_code = bytecode_1();
509   if (invoke_code != (Bytecodes::Code)0) {
510     Metadata* f1 = f1_ord();
511     if (f1 != NULL) {
512       switch (invoke_code) {
513       case Bytecodes::_invokeinterface:
514         assert(f1->is_klass(), "");
515         return f2_as_interface_method();
516       case Bytecodes::_invokestatic:
517       case Bytecodes::_invokespecial:
518         assert(!has_appendix(), "");
519       case Bytecodes::_invokehandle:
520       case Bytecodes::_invokedynamic:
521         assert(f1->is_method(), "");
522         return (Method*)f1;
523       default:
524         break;
525       }
526     }
527   }
528   invoke_code = bytecode_2();
529   if (invoke_code != (Bytecodes::Code)0) {
530     switch (invoke_code) {
531     case Bytecodes::_invokevirtual:
532       if (is_vfinal()) {
533         // invokevirtual
534         Method* m = f2_as_vfinal_method();
535         assert(m->is_method(), "");
536         return m;
537       } else {
538         int holder_index = cpool->uncached_klass_ref_index_at(constant_pool_index());
539         if (cpool->tag_at(holder_index).is_klass()) {
540           Klass* klass = cpool->resolved_klass_at(holder_index);
541           return klass->method_at_vtable(f2_as_index());
542         }
543       }
544       break;
545     default:
546       break;
547     }
548   }
549   return NULL;
550 }
551 
552 
553 oop ConstantPoolCacheEntry::appendix_if_resolved(const constantPoolHandle& cpool) {
554   if (!has_appendix())
555     return NULL;
556   const int ref_index = f2_as_index();
557   objArrayOop resolved_references = cpool->resolved_references();
558   return resolved_references->obj_at(ref_index);
559 }
560 
561 
562 #if INCLUDE_JVMTI
563 
564 void log_adjust(const char* entry_type, Method* old_method, Method* new_method, bool* trace_name_printed) {
565   ResourceMark rm;
566 
567   if (!(*trace_name_printed)) {
568     log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
569     *trace_name_printed = true;
570   }
571   log_trace(redefine, class, update, constantpool)
572     ("cpc %s entry update: %s", entry_type, new_method->external_name());
573 }
574 
575 // RedefineClasses() API support:
576 // If this ConstantPoolCacheEntry refers to old_method then update it
577 // to refer to new_method.
578 void ConstantPoolCacheEntry::adjust_method_entry(Method* old_method,
579        Method* new_method, bool * trace_name_printed) {
580 
581   if (is_vfinal()) {
582     // virtual and final so _f2 contains method ptr instead of vtable index
583     if (f2_as_vfinal_method() == old_method) {
584       // match old_method so need an update
585       // NOTE: can't use set_f2_as_vfinal_method as it asserts on different values
586       _f2 = (intptr_t)new_method;
587       log_adjust("vfinal", old_method, new_method, trace_name_printed);
588     }
589     return;
590   }
591 
592   assert (_f1 != NULL, "should not call with uninteresting entry");
593 
594   if (!(_f1->is_method())) {
595     // _f1 is a Klass* for an interface, _f2 is the method
596     if (f2_as_interface_method() == old_method) {
597       _f2 = (intptr_t)new_method;
598       log_adjust("interface", old_method, new_method, trace_name_printed);
599     }
600   } else if (_f1 == old_method) {
601     _f1 = new_method;
602     log_adjust("special, static or dynamic", old_method, new_method, trace_name_printed);
603   }
604 }
605 
606 // a constant pool cache entry should never contain old or obsolete methods
607 bool ConstantPoolCacheEntry::check_no_old_or_obsolete_entries() {
608   Method* m = get_interesting_method_entry();
609   // return false if m refers to a non-deleted old or obsolete method
610   if (m != NULL) {
611     assert(m->is_valid() && m->is_method(), "m is a valid method");
612     return !m->is_old() && !m->is_obsolete(); // old is always set for old and obsolete
613   } else {
614     return true;
615   }
616 }
617 
618 Method* ConstantPoolCacheEntry::get_interesting_method_entry() {
619   if (!is_method_entry()) {
620     // not a method entry so not interesting by default
621     return NULL;
622   }
623   Method* m = NULL;
624   if (is_vfinal()) {
625     // virtual and final so _f2 contains method ptr instead of vtable index
626     m = f2_as_vfinal_method();
627   } else if (is_f1_null()) {
628     // NULL _f1 means this is a virtual entry so also not interesting
629     return NULL;
630   } else {
631     if (!(_f1->is_method())) {
632       // _f1 is a Klass* for an interface
633       m = f2_as_interface_method();
634     } else {
635       m = f1_as_method();
636     }
637   }
638   assert(m != NULL && m->is_method(), "sanity check");
639   if (m == NULL || !m->is_method()) {
640     return NULL;
641   }
642   return m;
643 }
644 #endif // INCLUDE_JVMTI
645 
646 void ConstantPoolCacheEntry::print(outputStream* st, int index) const {
647   // print separator
648   if (index == 0) st->print_cr("                 -------------");
649   // print entry
650   st->print("%3d  (" PTR_FORMAT ")  ", index, (intptr_t)this);
651   st->print_cr("[%02x|%02x|%5d]", bytecode_2(), bytecode_1(),
652                constant_pool_index());
653   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f1);
654   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f2);
655   st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_flags);
656   st->print_cr("                 -------------");
657 }
658 
659 void ConstantPoolCacheEntry::verify(outputStream* st) const {
660   // not implemented yet
661 }
662 
663 // Implementation of ConstantPoolCache
664 
665 ConstantPoolCache* ConstantPoolCache::allocate(ClassLoaderData* loader_data,
666                                      const intStack& index_map,
667                                      const intStack& invokedynamic_index_map,
668                                      const intStack& invokedynamic_map, TRAPS) {
669 
670   const int length = index_map.length() + invokedynamic_index_map.length();
671   int size = ConstantPoolCache::size(length);
672 
673   return new (loader_data, size, MetaspaceObj::ConstantPoolCacheType, THREAD)
674     ConstantPoolCache(length, index_map, invokedynamic_index_map, invokedynamic_map);
675 }
676 
677 void ConstantPoolCache::initialize(const intArray& inverse_index_map,
678                                    const intArray& invokedynamic_inverse_index_map,
679                                    const intArray& invokedynamic_references_map) {
680   for (int i = 0; i < inverse_index_map.length(); i++) {
681     ConstantPoolCacheEntry* e = entry_at(i);
682     int original_index = inverse_index_map.at(i);
683     e->initialize_entry(original_index);
684     assert(entry_at(i) == e, "sanity");
685   }
686 
687   // Append invokedynamic entries at the end
688   int invokedynamic_offset = inverse_index_map.length();
689   for (int i = 0; i < invokedynamic_inverse_index_map.length(); i++) {
690     int offset = i + invokedynamic_offset;
691     ConstantPoolCacheEntry* e = entry_at(offset);
692     int original_index = invokedynamic_inverse_index_map.at(i);
693     e->initialize_entry(original_index);
694     assert(entry_at(offset) == e, "sanity");
695   }
696 
697   for (int ref = 0; ref < invokedynamic_references_map.length(); ref++) {
698     const int cpci = invokedynamic_references_map.at(ref);
699     if (cpci >= 0) {
700       entry_at(cpci)->initialize_resolved_reference_index(ref);
701     }
702   }
703 }
704 
705 void ConstantPoolCache::verify_just_initialized() {
706   DEBUG_ONLY(walk_entries_for_initialization(/*check_only = */ true));
707 }
708 
709 void ConstantPoolCache::remove_unshareable_info() {
710   walk_entries_for_initialization(/*check_only = */ false);
711 }
712 
713 void ConstantPoolCache::walk_entries_for_initialization(bool check_only) {
714   Arguments::assert_is_dumping_archive();
715   // When dumping the archive, we want to clean up the ConstantPoolCache
716   // to remove any effect of linking due to the execution of Java code --
717   // each ConstantPoolCacheEntry will have the same contents as if
718   // ConstantPoolCache::initialize has just returned:
719   //
720   // - We keep the ConstantPoolCache::constant_pool_index() bits for all entries.
721   // - We keep the "f2" field for entries used by invokedynamic and invokehandle
722   // - All other bits in the entries are cleared to zero.
723   ResourceMark rm;
724 
725   InstanceKlass* ik = constant_pool()->pool_holder();
726   bool* f2_used = NEW_RESOURCE_ARRAY(bool, length());
727   memset(f2_used, 0, sizeof(bool) * length());
728 
729   Thread* THREAD = Thread::current();
730 
731   // Find all the slots that we need to preserve f2
732   for (int i = 0; i < ik->methods()->length(); i++) {
733     Method* m = ik->methods()->at(i);
734     RawBytecodeStream bcs(methodHandle(THREAD, m));
735     while (!bcs.is_last_bytecode()) {
736       Bytecodes::Code opcode = bcs.raw_next();
737       switch (opcode) {
738       case Bytecodes::_invokedynamic: {
739           int index = Bytes::get_native_u4(bcs.bcp() + 1);
740           int cp_cache_index = constant_pool()->invokedynamic_cp_cache_index(index);
741           f2_used[cp_cache_index] = 1;
742         }
743         break;
744       case Bytecodes::_invokehandle: {
745           int cp_cache_index = Bytes::get_native_u2(bcs.bcp() + 1);
746           f2_used[cp_cache_index] = 1;
747         }
748         break;
749       default:
750         break;
751       }
752     }
753   }
754 
755   if (check_only) {
756     DEBUG_ONLY(
757       for (int i=0; i<length(); i++) {
758         entry_at(i)->verify_just_initialized(f2_used[i]);
759       })
760   } else {
761     for (int i=0; i<length(); i++) {
762       entry_at(i)->reinitialize(f2_used[i]);
763     }
764   }
765 }
766 
767 void ConstantPoolCache::deallocate_contents(ClassLoaderData* data) {
768   assert(!is_shared(), "shared caches are not deallocated");
769   data->remove_handle(_resolved_references);
770   set_resolved_references(OopHandle());
771   MetadataFactory::free_array<u2>(data, _reference_map);
772   set_reference_map(NULL);
773 }
774 
775 #if INCLUDE_CDS_JAVA_HEAP
776 oop ConstantPoolCache::archived_references() {
777   if (CompressedOops::is_null(_archived_references)) {
778     return NULL;
779   }
780   return HeapShared::materialize_archived_object(_archived_references);
781 }
782 
783 void ConstantPoolCache::set_archived_references(oop o) {
784   assert(DumpSharedSpaces, "called only during runtime");
785   _archived_references = CompressedOops::encode(o);
786 }
787 #endif
788 
789 #if INCLUDE_JVMTI
790 // RedefineClasses() API support:
791 // If any entry of this ConstantPoolCache points to any of
792 // old_methods, replace it with the corresponding new_method.
793 void ConstantPoolCache::adjust_method_entries(bool * trace_name_printed) {
794   for (int i = 0; i < length(); i++) {
795     ConstantPoolCacheEntry* entry = entry_at(i);
796     Method* old_method = entry->get_interesting_method_entry();
797     if (old_method == NULL || !old_method->is_old()) {
798       continue; // skip uninteresting entries
799     }
800     if (old_method->is_deleted()) {
801       // clean up entries with deleted methods
802       entry->initialize_entry(entry->constant_pool_index());
803       continue;
804     }
805     Method* new_method = old_method->get_new_method();
806     entry_at(i)->adjust_method_entry(old_method, new_method, trace_name_printed);
807   }
808 }
809 
810 // the constant pool cache should never contain old or obsolete methods
811 bool ConstantPoolCache::check_no_old_or_obsolete_entries() {
812   ResourceMark rm;
813   for (int i = 1; i < length(); i++) {
814     Method* m = entry_at(i)->get_interesting_method_entry();
815     if (m != NULL && !entry_at(i)->check_no_old_or_obsolete_entries()) {
816       log_trace(redefine, class, update, constantpool)
817         ("cpcache check found old method entry: class: %s, old: %d, obsolete: %d, method: %s",
818          constant_pool()->pool_holder()->external_name(), m->is_old(), m->is_obsolete(), m->external_name());
819       return false;
820     }
821   }
822   return true;
823 }
824 
825 void ConstantPoolCache::dump_cache() {
826   for (int i = 1; i < length(); i++) {
827     if (entry_at(i)->get_interesting_method_entry() != NULL) {
828       entry_at(i)->print(tty, i);
829     }
830   }
831 }
832 #endif // INCLUDE_JVMTI
833 
834 void ConstantPoolCache::metaspace_pointers_do(MetaspaceClosure* it) {
835   log_trace(cds)("Iter(ConstantPoolCache): %p", this);
836   it->push(&_constant_pool);
837   it->push(&_reference_map);
838 }
839 
840 // Printing
841 
842 void ConstantPoolCache::print_on(outputStream* st) const {
843   st->print_cr("%s", internal_name());
844   // print constant pool cache entries
845   for (int i = 0; i < length(); i++) entry_at(i)->print(st, i);
846 }
847 
848 void ConstantPoolCache::print_value_on(outputStream* st) const {
849   st->print("cache [%d]", length());
850   print_address_on(st);
851   st->print(" for ");
852   constant_pool()->print_value_on(st);
853 }
854 
855 
856 // Verification
857 
858 void ConstantPoolCache::verify_on(outputStream* st) {
859   // print constant pool cache entries
860   for (int i = 0; i < length(); i++) entry_at(i)->verify(st);
861 }