1 /*
   2  * Copyright (c) 1997, 2025, 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 "cds/cdsConfig.hpp"
  26 #include "cds/cppVtables.hpp"
  27 #include "cds/metaspaceShared.hpp"
  28 #include "classfile/classLoader.hpp"
  29 #include "classfile/classLoaderDataGraph.hpp"
  30 #include "classfile/metadataOnStackMark.hpp"
  31 #include "classfile/symbolTable.hpp"
  32 #include "classfile/systemDictionary.hpp"
  33 #include "classfile/vmClasses.hpp"
  34 #include "code/codeCache.hpp"
  35 #include "code/debugInfoRec.hpp"
  36 #include "compiler/compilationPolicy.hpp"
  37 #include "gc/shared/collectedHeap.inline.hpp"
  38 #include "interpreter/bytecodeStream.hpp"
  39 #include "interpreter/bytecodeTracer.hpp"
  40 #include "interpreter/bytecodes.hpp"
  41 #include "interpreter/interpreter.hpp"
  42 #include "interpreter/oopMapCache.hpp"
  43 #include "logging/log.hpp"
  44 #include "logging/logStream.hpp"
  45 #include "logging/logTag.hpp"
  46 #include "memory/allocation.inline.hpp"
  47 #include "memory/metadataFactory.hpp"
  48 #include "memory/metaspaceClosure.hpp"
  49 #include "memory/oopFactory.hpp"
  50 #include "memory/resourceArea.hpp"
  51 #include "memory/universe.hpp"
  52 #include "nmt/memTracker.hpp"
  53 #include "oops/constMethod.hpp"
  54 #include "oops/constantPool.hpp"
  55 #include "oops/klass.inline.hpp"
  56 #include "oops/method.inline.hpp"
  57 #include "oops/methodData.hpp"
  58 #include "oops/objArrayKlass.hpp"
  59 #include "oops/objArrayOop.inline.hpp"
  60 #include "oops/oop.inline.hpp"
  61 #include "oops/symbol.hpp"
  62 #include "oops/trainingData.hpp"
  63 #include "prims/jvmtiExport.hpp"
  64 #include "prims/methodHandles.hpp"
  65 #include "runtime/atomic.hpp"
  66 #include "runtime/arguments.hpp"
  67 #include "runtime/continuationEntry.hpp"
  68 #include "runtime/frame.inline.hpp"
  69 #include "runtime/handles.inline.hpp"
  70 #include "runtime/init.hpp"
  71 #include "runtime/java.hpp"
  72 #include "runtime/orderAccess.hpp"
  73 #include "runtime/perfData.hpp"
  74 #include "runtime/relocator.hpp"
  75 #include "runtime/safepointVerifiers.hpp"
  76 #include "runtime/sharedRuntime.hpp"
  77 #include "runtime/signature.hpp"
  78 #include "runtime/threads.hpp"
  79 #include "runtime/vm_version.hpp"
  80 #include "utilities/align.hpp"
  81 #include "utilities/quickSort.hpp"
  82 #include "utilities/vmError.hpp"
  83 #include "utilities/xmlstream.hpp"
  84 
  85 // Implementation of Method
  86 
  87 Method* Method::allocate(ClassLoaderData* loader_data,
  88                          int byte_code_size,
  89                          AccessFlags access_flags,
  90                          InlineTableSizes* sizes,
  91                          ConstMethod::MethodType method_type,
  92                          Symbol* name,
  93                          TRAPS) {
  94   assert(!access_flags.is_native() || byte_code_size == 0,
  95          "native methods should not contain byte codes");
  96   ConstMethod* cm = ConstMethod::allocate(loader_data,
  97                                           byte_code_size,
  98                                           sizes,
  99                                           method_type,
 100                                           CHECK_NULL);
 101   int size = Method::size(access_flags.is_native());
 102   return new (loader_data, size, MetaspaceObj::MethodType, THREAD) Method(cm, access_flags, name);
 103 }
 104 
 105 Method::Method(ConstMethod* xconst, AccessFlags access_flags, Symbol* name) {
 106   NoSafepointVerifier no_safepoint;
 107   set_constMethod(xconst);
 108   set_access_flags(access_flags);
 109   set_intrinsic_id(vmIntrinsics::_none);
 110   clear_method_data();
 111   clear_method_counters();
 112   set_vtable_index(Method::garbage_vtable_index);
 113 
 114   // Fix and bury in Method*
 115   set_interpreter_entry(nullptr); // sets i2i entry and from_int
 116   set_adapter_entry(nullptr);
 117   Method::clear_code(); // from_c/from_i get set to c2i/i2i
 118 
 119   if (access_flags.is_native()) {
 120     clear_native_function();
 121     set_signature_handler(nullptr);
 122   }
 123 
 124   NOT_PRODUCT(set_compiled_invocation_count(0);)
 125   // Name is very useful for debugging.
 126   NOT_PRODUCT(_name = name;)
 127 }
 128 
 129 // Release Method*.  The nmethod will be gone when we get here because
 130 // we've walked the code cache.
 131 void Method::deallocate_contents(ClassLoaderData* loader_data) {
 132   MetadataFactory::free_metadata(loader_data, constMethod());
 133   set_constMethod(nullptr);
 134   MetadataFactory::free_metadata(loader_data, method_data());
 135   clear_method_data();
 136   MetadataFactory::free_metadata(loader_data, method_counters());
 137   clear_method_counters();
 138   // The nmethod will be gone when we get here.
 139   if (code() != nullptr) _code = nullptr;
 140 }
 141 
 142 void Method::release_C_heap_structures() {
 143   if (method_data()) {
 144     method_data()->release_C_heap_structures();
 145 
 146     // Destroy MethodData embedded lock
 147     method_data()->~MethodData();
 148   }
 149 }
 150 
 151 address Method::get_i2c_entry() {
 152   assert(adapter() != nullptr, "must have");
 153   return adapter()->get_i2c_entry();
 154 }
 155 
 156 address Method::get_c2i_entry() {
 157   assert(adapter() != nullptr, "must have");
 158   return adapter()->get_c2i_entry();
 159 }
 160 
 161 address Method::get_c2i_unverified_entry() {
 162   assert(adapter() != nullptr, "must have");
 163   return adapter()->get_c2i_unverified_entry();
 164 }
 165 
 166 address Method::get_c2i_no_clinit_check_entry() {
 167   assert(VM_Version::supports_fast_class_init_checks(), "");
 168   assert(adapter() != nullptr, "must have");
 169   return adapter()->get_c2i_no_clinit_check_entry();
 170 }
 171 
 172 char* Method::name_and_sig_as_C_string() const {
 173   return name_and_sig_as_C_string(constants()->pool_holder(), name(), signature());
 174 }
 175 
 176 char* Method::name_and_sig_as_C_string(char* buf, int size) const {
 177   return name_and_sig_as_C_string(constants()->pool_holder(), name(), signature(), buf, size);
 178 }
 179 
 180 char* Method::name_and_sig_as_C_string(Klass* klass, Symbol* method_name, Symbol* signature) {
 181   const char* klass_name = klass->external_name();
 182   int klass_name_len  = (int)strlen(klass_name);
 183   int method_name_len = method_name->utf8_length();
 184   int len             = klass_name_len + 2 + method_name_len + signature->utf8_length();
 185   char* dest          = NEW_RESOURCE_ARRAY(char, len + 1);
 186   strcpy(dest, klass_name);
 187   dest[klass_name_len + 0] = ':';
 188   dest[klass_name_len + 1] = ':';
 189   strcpy(&dest[klass_name_len + 2], method_name->as_C_string());
 190   strcpy(&dest[klass_name_len + 2 + method_name_len], signature->as_C_string());
 191   dest[len] = 0;
 192   return dest;
 193 }
 194 
 195 char* Method::name_and_sig_as_C_string(Klass* klass, Symbol* method_name, Symbol* signature, char* buf, int size) {
 196   Symbol* klass_name = klass->name();
 197   klass_name->as_klass_external_name(buf, size);
 198   int len = (int)strlen(buf);
 199 
 200   if (len < size - 1) {
 201     buf[len++] = '.';
 202 
 203     method_name->as_C_string(&(buf[len]), size - len);
 204     len = (int)strlen(buf);
 205 
 206     signature->as_C_string(&(buf[len]), size - len);
 207   }
 208 
 209   return buf;
 210 }
 211 
 212 const char* Method::external_name() const {
 213   return external_name(constants()->pool_holder(), name(), signature());
 214 }
 215 
 216 void Method::print_external_name(outputStream *os) const {
 217   print_external_name(os, constants()->pool_holder(), name(), signature());
 218 }
 219 
 220 const char* Method::external_name(Klass* klass, Symbol* method_name, Symbol* signature) {
 221   stringStream ss;
 222   print_external_name(&ss, klass, method_name, signature);
 223   return ss.as_string();
 224 }
 225 
 226 void Method::print_external_name(outputStream *os, Klass* klass, Symbol* method_name, Symbol* signature) {
 227   signature->print_as_signature_external_return_type(os);
 228   os->print(" %s.%s(", klass->external_name(), method_name->as_C_string());
 229   signature->print_as_signature_external_parameters(os);
 230   os->print(")");
 231 }
 232 
 233 int Method::fast_exception_handler_bci_for(const methodHandle& mh, Klass* ex_klass, int throw_bci, TRAPS) {
 234   if (log_is_enabled(Debug, exceptions)) {
 235     ResourceMark rm(THREAD);
 236     log_debug(exceptions)("Looking for catch handler for exception of type \"%s\" in method \"%s\"",
 237                           ex_klass == nullptr ? "null" : ex_klass->external_name(), mh->name()->as_C_string());
 238   }
 239   // exception table holds quadruple entries of the form (beg_bci, end_bci, handler_bci, klass_index)
 240   // access exception table
 241   ExceptionTable table(mh());
 242   int length = table.length();
 243   // iterate through all entries sequentially
 244   constantPoolHandle pool(THREAD, mh->constants());
 245   for (int i = 0; i < length; i ++) {
 246     //reacquire the table in case a GC happened
 247     ExceptionTable table(mh());
 248     int beg_bci = table.start_pc(i);
 249     int end_bci = table.end_pc(i);
 250     assert(beg_bci <= end_bci, "inconsistent exception table");
 251     log_debug(exceptions)("  - checking exception table entry for BCI %d to %d",
 252                          beg_bci, end_bci);
 253 
 254     if (beg_bci <= throw_bci && throw_bci < end_bci) {
 255       // exception handler bci range covers throw_bci => investigate further
 256       log_debug(exceptions)("    - entry covers throw point BCI %d", throw_bci);
 257 
 258       int handler_bci = table.handler_pc(i);
 259       int klass_index = table.catch_type_index(i);
 260       if (klass_index == 0) {
 261         if (log_is_enabled(Info, exceptions)) {
 262           ResourceMark rm(THREAD);
 263           log_info(exceptions)("Found catch-all handler for exception of type \"%s\" in method \"%s\" at BCI: %d",
 264                                ex_klass == nullptr ? "null" : ex_klass->external_name(), mh->name()->as_C_string(), handler_bci);
 265         }
 266         return handler_bci;
 267       } else if (ex_klass == nullptr) {
 268         // Is this even possible?
 269         if (log_is_enabled(Info, exceptions)) {
 270           ResourceMark rm(THREAD);
 271           log_info(exceptions)("null exception class is implicitly caught by handler in method \"%s\" at BCI: %d",
 272                                mh()->name()->as_C_string(), handler_bci);
 273         }
 274         return handler_bci;
 275       } else {
 276         if (log_is_enabled(Debug, exceptions)) {
 277           ResourceMark rm(THREAD);
 278           log_debug(exceptions)("    - resolving catch type \"%s\"",
 279                                pool->klass_name_at(klass_index)->as_C_string());
 280         }
 281         // we know the exception class => get the constraint class
 282         // this may require loading of the constraint class; if verification
 283         // fails or some other exception occurs, return handler_bci
 284         Klass* k = pool->klass_at(klass_index, THREAD);
 285         if (HAS_PENDING_EXCEPTION) {
 286           if (log_is_enabled(Debug, exceptions)) {
 287             ResourceMark rm(THREAD);
 288             log_debug(exceptions)("    - exception \"%s\" occurred resolving catch type",
 289                                  PENDING_EXCEPTION->klass()->external_name());
 290           }
 291           return handler_bci;
 292         }
 293         assert(k != nullptr, "klass not loaded");
 294         if (ex_klass->is_subtype_of(k)) {
 295           if (log_is_enabled(Info, exceptions)) {
 296             ResourceMark rm(THREAD);
 297             log_info(exceptions)("Found matching handler for exception of type \"%s\" in method \"%s\" at BCI: %d",
 298                                  ex_klass == nullptr ? "null" : ex_klass->external_name(), mh->name()->as_C_string(), handler_bci);
 299           }
 300           return handler_bci;
 301         }
 302       }
 303     }
 304   }
 305 
 306   if (log_is_enabled(Debug, exceptions)) {
 307     ResourceMark rm(THREAD);
 308     log_debug(exceptions)("No catch handler found for exception of type \"%s\" in method \"%s\"",
 309                           ex_klass->external_name(), mh->name()->as_C_string());
 310   }
 311 
 312   return -1;
 313 }
 314 
 315 void Method::mask_for(int bci, InterpreterOopMap* mask) {
 316   methodHandle h_this(Thread::current(), this);
 317   mask_for(h_this, bci, mask);
 318 }
 319 
 320 void Method::mask_for(const methodHandle& this_mh, int bci, InterpreterOopMap* mask) {
 321   assert(this_mh() == this, "Sanity");
 322   method_holder()->mask_for(this_mh, bci, mask);
 323 }
 324 
 325 int Method::bci_from(address bcp) const {
 326   if (is_native() && bcp == nullptr) {
 327     return 0;
 328   }
 329   // Do not have a ResourceMark here because AsyncGetCallTrace stack walking code
 330   // may call this after interrupting a nested ResourceMark.
 331   assert((is_native() && bcp == code_base()) || contains(bcp) || VMError::is_error_reported(),
 332          "bcp doesn't belong to this method. bcp: " PTR_FORMAT, p2i(bcp));
 333 
 334   return int(bcp - code_base());
 335 }
 336 
 337 
 338 int Method::validate_bci(int bci) const {
 339   // Called from the verifier, and should return -1 if not valid.
 340   return ((is_native() && bci == 0) || (!is_native() && 0 <= bci && bci < code_size())) ? bci : -1;
 341 }
 342 
 343 // Return bci if it appears to be a valid bcp
 344 // Return -1 otherwise.
 345 // Used by profiling code, when invalid data is a possibility.
 346 // The caller is responsible for validating the Method* itself.
 347 int Method::validate_bci_from_bcp(address bcp) const {
 348   // keep bci as -1 if not a valid bci
 349   int bci = -1;
 350   if (bcp == nullptr || bcp == code_base()) {
 351     // code_size() may return 0 and we allow 0 here
 352     // the method may be native
 353     bci = 0;
 354   } else if (contains(bcp)) {
 355     bci = int(bcp - code_base());
 356   }
 357   // Assert that if we have dodged any asserts, bci is negative.
 358   assert(bci == -1 || bci == bci_from(bcp_from(bci)), "sane bci if >=0");
 359   return bci;
 360 }
 361 
 362 address Method::bcp_from(int bci) const {
 363   assert((is_native() && bci == 0) || (!is_native() && 0 <= bci && bci < code_size()),
 364          "illegal bci: %d for %s method", bci, is_native() ? "native" : "non-native");
 365   address bcp = code_base() + bci;
 366   assert((is_native() && bcp == code_base()) || contains(bcp), "bcp doesn't belong to this method");
 367   return bcp;
 368 }
 369 
 370 address Method::bcp_from(address bcp) const {
 371   if (is_native() && bcp == nullptr) {
 372     return code_base();
 373   } else {
 374     return bcp;
 375   }
 376 }
 377 
 378 int Method::size(bool is_native) {
 379   // If native, then include pointers for native_function and signature_handler
 380   int extra_bytes = (is_native) ? 2*sizeof(address*) : 0;
 381   int extra_words = align_up(extra_bytes, BytesPerWord) / BytesPerWord;
 382   return align_metadata_size(header_size() + extra_words);
 383 }
 384 
 385 Symbol* Method::klass_name() const {
 386   return method_holder()->name();
 387 }
 388 
 389 void Method::metaspace_pointers_do(MetaspaceClosure* it) {
 390   LogStreamHandle(Trace, cds) lsh;
 391   if (lsh.is_enabled()) {
 392     lsh.print("Iter(Method): %p ", this);
 393     print_external_name(&lsh);
 394     lsh.cr();
 395   }
 396   if (method_holder() != nullptr && !method_holder()->is_rewritten()) {
 397     // holder is null for MH intrinsic methods
 398     it->push(&_constMethod, MetaspaceClosure::_writable);
 399   } else {
 400     it->push(&_constMethod);
 401   }
 402   it->push(&_adapter);
 403   it->push(&_method_data);
 404   it->push(&_method_counters);
 405   NOT_PRODUCT(it->push(&_name);)
 406 }
 407 
 408 #if INCLUDE_CDS
 409 // Attempt to return method to original state.  Clear any pointers
 410 // (to objects outside the shared spaces).  We won't be able to predict
 411 // where they should point in a new JVM.  Further initialize some
 412 // entries now in order allow them to be write protected later.
 413 
 414 void Method::remove_unshareable_info() {
 415   unlink_method();
 416   if (CDSConfig::is_dumping_adapters() && _adapter != nullptr) {
 417     _adapter->remove_unshareable_info();
 418   }
 419   if (method_data() != nullptr) {
 420     method_data()->remove_unshareable_info();
 421   }
 422   if (method_counters() != nullptr) {
 423     method_counters()->remove_unshareable_info();
 424   }
 425   JFR_ONLY(REMOVE_METHOD_ID(this);)
 426 }
 427 
 428 void Method::restore_adapter(TRAPS) {
 429   if (_adapter != nullptr) {
 430     _adapter->restore_unshareable_info(CHECK);
 431     _from_compiled_entry = _adapter->get_c2i_entry();
 432   }
 433 }
 434 
 435 void Method::restore_unshareable_info(TRAPS) {
 436   assert(is_method() && is_valid_method(this), "ensure C++ vtable is restored");
 437   restore_adapter(CHECK);
 438   if (method_data() != nullptr) {
 439     method_data()->restore_unshareable_info(CHECK);
 440   }
 441   if (method_counters() != nullptr) {
 442     method_counters()->restore_unshareable_info(CHECK);
 443   }
 444   assert(!queued_for_compilation(), "method's queued_for_compilation flag should not be set");
 445   assert(!pending_queue_processed(), "method's pending_queued_processed flag should not be set");
 446 }
 447 #endif
 448 
 449 void Method::set_vtable_index(int index) {
 450   if (is_shared() && !MetaspaceShared::remapped_readwrite() && method_holder()->verified_at_dump_time()) {
 451     // At runtime initialize_vtable is rerun as part of link_class_impl()
 452     // for a shared class loaded by the non-boot loader to obtain the loader
 453     // constraints based on the runtime classloaders' context.
 454     return; // don't write into the shared class
 455   } else {
 456     _vtable_index = index;
 457   }
 458 }
 459 
 460 void Method::set_itable_index(int index) {
 461   if (is_shared() && !MetaspaceShared::remapped_readwrite() && method_holder()->verified_at_dump_time()) {
 462     // At runtime initialize_itable is rerun as part of link_class_impl()
 463     // for a shared class loaded by the non-boot loader to obtain the loader
 464     // constraints based on the runtime classloaders' context. The dumptime
 465     // itable index should be the same as the runtime index.
 466     assert(_vtable_index == itable_index_max - index,
 467            "archived itable index is different from runtime index");
 468     return; // don’t write into the shared class
 469   } else {
 470     _vtable_index = itable_index_max - index;
 471   }
 472   assert(valid_itable_index(), "");
 473 }
 474 
 475 // The RegisterNatives call being attempted tried to register with a method that
 476 // is not native.  Ask JVM TI what prefixes have been specified.  Then check
 477 // to see if the native method is now wrapped with the prefixes.  See the
 478 // SetNativeMethodPrefix(es) functions in the JVM TI Spec for details.
 479 static Method* find_prefixed_native(Klass* k, Symbol* name, Symbol* signature, TRAPS) {
 480 #if INCLUDE_JVMTI
 481   ResourceMark rm(THREAD);
 482   Method* method;
 483   int name_len = name->utf8_length();
 484   char* name_str = name->as_utf8();
 485   int prefix_count;
 486   char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
 487   for (int i = 0; i < prefix_count; i++) {
 488     char* prefix = prefixes[i];
 489     int prefix_len = (int)strlen(prefix);
 490 
 491     // try adding this prefix to the method name and see if it matches another method name
 492     int trial_len = name_len + prefix_len;
 493     char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
 494     strcpy(trial_name_str, prefix);
 495     strcat(trial_name_str, name_str);
 496     TempNewSymbol trial_name = SymbolTable::probe(trial_name_str, trial_len);
 497     if (trial_name == nullptr) {
 498       continue; // no such symbol, so this prefix wasn't used, try the next prefix
 499     }
 500     method = k->lookup_method(trial_name, signature);
 501     if (method == nullptr) {
 502       continue; // signature doesn't match, try the next prefix
 503     }
 504     if (method->is_native()) {
 505       method->set_is_prefixed_native();
 506       return method; // wahoo, we found a prefixed version of the method, return it
 507     }
 508     // found as non-native, so prefix is good, add it, probably just need more prefixes
 509     name_len = trial_len;
 510     name_str = trial_name_str;
 511   }
 512 #endif // INCLUDE_JVMTI
 513   return nullptr; // not found
 514 }
 515 
 516 bool Method::register_native(Klass* k, Symbol* name, Symbol* signature, address entry, TRAPS) {
 517   Method* method = k->lookup_method(name, signature);
 518   if (method == nullptr) {
 519     ResourceMark rm(THREAD);
 520     stringStream st;
 521     st.print("Method '");
 522     print_external_name(&st, k, name, signature);
 523     st.print("' name or signature does not match");
 524     THROW_MSG_(vmSymbols::java_lang_NoSuchMethodError(), st.as_string(), false);
 525   }
 526   if (!method->is_native()) {
 527     // trying to register to a non-native method, see if a JVM TI agent has added prefix(es)
 528     method = find_prefixed_native(k, name, signature, THREAD);
 529     if (method == nullptr) {
 530       ResourceMark rm(THREAD);
 531       stringStream st;
 532       st.print("Method '");
 533       print_external_name(&st, k, name, signature);
 534       st.print("' is not declared as native");
 535       THROW_MSG_(vmSymbols::java_lang_NoSuchMethodError(), st.as_string(), false);
 536     }
 537   }
 538 
 539   if (entry != nullptr) {
 540     method->set_native_function(entry, native_bind_event_is_interesting);
 541   } else {
 542     method->clear_native_function();
 543   }
 544   if (log_is_enabled(Debug, jni, resolve)) {
 545     ResourceMark rm(THREAD);
 546     log_debug(jni, resolve)("[Registering JNI native method %s.%s]",
 547                             method->method_holder()->external_name(),
 548                             method->name()->as_C_string());
 549   }
 550   return true;
 551 }
 552 
 553 bool Method::was_executed_more_than(int n) {
 554   // Invocation counter is reset when the Method* is compiled.
 555   // If the method has compiled code we therefore assume it has
 556   // be executed more than n times.
 557   if (is_accessor() || is_empty_method() || (code() != nullptr)) {
 558     // interpreter doesn't bump invocation counter of trivial methods
 559     // compiler does not bump invocation counter of compiled methods
 560     return true;
 561   }
 562   else if ((method_counters() != nullptr &&
 563             method_counters()->invocation_counter()->carry()) ||
 564            (method_data() != nullptr &&
 565             method_data()->invocation_counter()->carry())) {
 566     // The carry bit is set when the counter overflows and causes
 567     // a compilation to occur.  We don't know how many times
 568     // the counter has been reset, so we simply assume it has
 569     // been executed more than n times.
 570     return true;
 571   } else {
 572     return invocation_count() > n;
 573   }
 574 }
 575 
 576 void Method::print_invocation_count(outputStream* st) {
 577   //---<  compose+print method return type, klass, name, and signature  >---
 578   if (is_static())       { st->print("static "); }
 579   if (is_final())        { st->print("final "); }
 580   if (is_synchronized()) { st->print("synchronized "); }
 581   if (is_native())       { st->print("native "); }
 582   st->print("%s::", method_holder()->external_name());
 583   name()->print_symbol_on(st);
 584   signature()->print_symbol_on(st);
 585 
 586   if (WizardMode) {
 587     // dump the size of the byte codes
 588     st->print(" {%d}", code_size());
 589   }
 590   st->cr();
 591 
 592   // Counting based on signed int counters tends to overflow with
 593   // longer-running workloads on fast machines. The counters under
 594   // consideration here, however, are limited in range by counting
 595   // logic. See InvocationCounter:count_limit for example.
 596   // No "overflow precautions" need to be implemented here.
 597   st->print_cr ("  interpreter_invocation_count: " INT32_FORMAT_W(11), interpreter_invocation_count());
 598   st->print_cr ("  invocation_counter:           " INT32_FORMAT_W(11), invocation_count());
 599   st->print_cr ("  backedge_counter:             " INT32_FORMAT_W(11), backedge_count());
 600 
 601   if (method_data() != nullptr) {
 602     st->print_cr ("  decompile_count:              " UINT32_FORMAT_W(11), method_data()->decompile_count());
 603   }
 604 
 605 #ifndef PRODUCT
 606   if (CountCompiledCalls) {
 607     st->print_cr ("  compiled_invocation_count:    " INT64_FORMAT_W(11), compiled_invocation_count());
 608   }
 609 #endif
 610 }
 611 
 612 MethodTrainingData* Method::training_data_or_null() const {
 613   MethodCounters* mcs = method_counters();
 614   if (mcs == nullptr) {
 615     return nullptr;
 616   } else {
 617     MethodTrainingData* mtd = mcs->method_training_data();
 618     if (mtd == mcs->method_training_data_sentinel()) {
 619       return nullptr;
 620     }
 621     return mtd;
 622   }
 623 }
 624 
 625 bool Method::init_training_data(MethodTrainingData* tdata) {
 626   MethodCounters* mcs = method_counters();
 627   if (mcs == nullptr) {
 628     return false;
 629   } else {
 630     return mcs->init_method_training_data(tdata);
 631   }
 632 }
 633 
 634 bool Method::install_training_method_data(const methodHandle& method) {
 635   MethodTrainingData* mtd = MethodTrainingData::find(method);
 636   if (mtd != nullptr && mtd->has_holder() && mtd->final_profile() != nullptr &&
 637       mtd->holder() == method() && mtd->final_profile()->method() == method()) { // FIXME
 638     Atomic::replace_if_null(&method->_method_data, mtd->final_profile());
 639     return true;
 640   }
 641   return false;
 642 }
 643 
 644 // Build a MethodData* object to hold profiling information collected on this
 645 // method when requested.
 646 void Method::build_profiling_method_data(const methodHandle& method, TRAPS) {
 647   if (install_training_method_data(method)) {
 648     return;
 649   }
 650   // Do not profile the method if metaspace has hit an OOM previously
 651   // allocating profiling data. Callers clear pending exception so don't
 652   // add one here.
 653   if (ClassLoaderDataGraph::has_metaspace_oom()) {
 654     return;
 655   }
 656 
 657   ClassLoaderData* loader_data = method->method_holder()->class_loader_data();
 658   MethodData* method_data = MethodData::allocate(loader_data, method, THREAD);
 659   if (HAS_PENDING_EXCEPTION) {
 660     CompileBroker::log_metaspace_failure();
 661     ClassLoaderDataGraph::set_metaspace_oom(true);
 662     return;   // return the exception (which is cleared)
 663   }
 664 
 665   if (!Atomic::replace_if_null(&method->_method_data, method_data)) {
 666     MetadataFactory::free_metadata(loader_data, method_data);
 667     return;
 668   }
 669 
 670   /*
 671   LogStreamHandle(Info, mdo) lsh;
 672   if (lsh.is_enabled()) {
 673     ResourceMark rm(THREAD);
 674     lsh.print("build_profiling_method_data for ");
 675     method->print_name(&lsh);
 676     lsh.cr();
 677   }
 678   */
 679   if (ForceProfiling && TrainingData::need_data()) {
 680     MethodTrainingData* mtd = MethodTrainingData::make(method, false);
 681     guarantee(mtd != nullptr, "");
 682   }
 683   if (PrintMethodData) {
 684     ResourceMark rm(THREAD);
 685     tty->print("build_profiling_method_data for ");
 686     method->print_name(tty);
 687     tty->cr();
 688     // At the end of the run, the MDO, full of data, will be dumped.
 689   }
 690 }
 691 
 692 MethodCounters* Method::build_method_counters(Thread* current, Method* m) {
 693   // Do not profile the method if metaspace has hit an OOM previously
 694   if (ClassLoaderDataGraph::has_metaspace_oom()) {
 695     return nullptr;
 696   }
 697 
 698   methodHandle mh(current, m);
 699   MethodCounters* counters;
 700   if (current->is_Java_thread()) {
 701     JavaThread* THREAD = JavaThread::cast(current); // For exception macros.
 702     // Use the TRAPS version for a JavaThread so it will adjust the GC threshold
 703     // if needed.
 704     counters = MethodCounters::allocate_with_exception(mh, THREAD);
 705     if (HAS_PENDING_EXCEPTION) {
 706       CLEAR_PENDING_EXCEPTION;
 707     }
 708   } else {
 709     // Call metaspace allocation that doesn't throw exception if the
 710     // current thread isn't a JavaThread, ie. the VMThread.
 711     counters = MethodCounters::allocate_no_exception(mh);
 712   }
 713 
 714   if (counters == nullptr) {
 715     CompileBroker::log_metaspace_failure();
 716     ClassLoaderDataGraph::set_metaspace_oom(true);
 717     return nullptr;
 718   }
 719 
 720   if (!mh->init_method_counters(counters)) {
 721     MetadataFactory::free_metadata(mh->method_holder()->class_loader_data(), counters);
 722   }
 723 
 724   if (ForceProfiling && TrainingData::need_data()) {
 725     MethodTrainingData* mtd = MethodTrainingData::make(mh, false);
 726     guarantee(mtd != nullptr, "");
 727   }
 728 
 729   return mh->method_counters();
 730 }
 731 
 732 bool Method::init_method_counters(MethodCounters* counters) {
 733   // Try to install a pointer to MethodCounters, return true on success.
 734   return Atomic::replace_if_null(&_method_counters, counters);
 735 }
 736 
 737 void Method::set_exception_handler_entered(int handler_bci) {
 738   if (ProfileExceptionHandlers) {
 739     MethodData* mdo = method_data();
 740     if (mdo != nullptr) {
 741       BitData handler_data = mdo->exception_handler_bci_to_data(handler_bci);
 742       handler_data.set_exception_handler_entered();
 743     }
 744   }
 745 }
 746 
 747 int Method::extra_stack_words() {
 748   // not an inline function, to avoid a header dependency on Interpreter
 749   return extra_stack_entries() * Interpreter::stackElementSize;
 750 }
 751 
 752 bool Method::compute_has_loops_flag() {
 753   BytecodeStream bcs(methodHandle(Thread::current(), this));
 754   Bytecodes::Code bc;
 755 
 756   while ((bc = bcs.next()) >= 0) {
 757     switch (bc) {
 758       case Bytecodes::_ifeq:
 759       case Bytecodes::_ifnull:
 760       case Bytecodes::_iflt:
 761       case Bytecodes::_ifle:
 762       case Bytecodes::_ifne:
 763       case Bytecodes::_ifnonnull:
 764       case Bytecodes::_ifgt:
 765       case Bytecodes::_ifge:
 766       case Bytecodes::_if_icmpeq:
 767       case Bytecodes::_if_icmpne:
 768       case Bytecodes::_if_icmplt:
 769       case Bytecodes::_if_icmpgt:
 770       case Bytecodes::_if_icmple:
 771       case Bytecodes::_if_icmpge:
 772       case Bytecodes::_if_acmpeq:
 773       case Bytecodes::_if_acmpne:
 774       case Bytecodes::_goto:
 775       case Bytecodes::_jsr:
 776         if (bcs.dest() < bcs.next_bci()) {
 777           return set_has_loops();
 778         }
 779         break;
 780 
 781       case Bytecodes::_goto_w:
 782       case Bytecodes::_jsr_w:
 783         if (bcs.dest_w() < bcs.next_bci()) {
 784           return set_has_loops();
 785         }
 786         break;
 787 
 788       case Bytecodes::_lookupswitch: {
 789         Bytecode_lookupswitch lookupswitch(this, bcs.bcp());
 790         if (lookupswitch.default_offset() < 0) {
 791           return set_has_loops();
 792         } else {
 793           for (int i = 0; i < lookupswitch.number_of_pairs(); ++i) {
 794             LookupswitchPair pair = lookupswitch.pair_at(i);
 795             if (pair.offset() < 0) {
 796               return set_has_loops();
 797             }
 798           }
 799         }
 800         break;
 801       }
 802       case Bytecodes::_tableswitch: {
 803         Bytecode_tableswitch tableswitch(this, bcs.bcp());
 804         if (tableswitch.default_offset() < 0) {
 805           return set_has_loops();
 806         } else {
 807           for (int i = 0; i < tableswitch.length(); ++i) {
 808             if (tableswitch.dest_offset_at(i) < 0) {
 809               return set_has_loops();
 810             }
 811           }
 812         }
 813         break;
 814       }
 815       default:
 816         break;
 817     }
 818   }
 819 
 820   _flags.set_has_loops_flag_init(true);
 821   return false;
 822 }
 823 
 824 bool Method::is_final_method(AccessFlags class_access_flags) const {
 825   // or "does_not_require_vtable_entry"
 826   // default method or overpass can occur, is not final (reuses vtable entry)
 827   // private methods in classes get vtable entries for backward class compatibility.
 828   if (is_overpass() || is_default_method())  return false;
 829   return is_final() || class_access_flags.is_final();
 830 }
 831 
 832 bool Method::is_final_method() const {
 833   return is_final_method(method_holder()->access_flags());
 834 }
 835 
 836 bool Method::is_default_method() const {
 837   if (method_holder() != nullptr &&
 838       method_holder()->is_interface() &&
 839       !is_abstract() && !is_private()) {
 840     return true;
 841   } else {
 842     return false;
 843   }
 844 }
 845 
 846 bool Method::can_be_statically_bound(AccessFlags class_access_flags) const {
 847   if (is_final_method(class_access_flags))  return true;
 848 #ifdef ASSERT
 849   bool is_nonv = (vtable_index() == nonvirtual_vtable_index);
 850   if (class_access_flags.is_interface()) {
 851       ResourceMark rm;
 852       assert(is_nonv == is_static() || is_nonv == is_private(),
 853              "nonvirtual unexpected for non-static, non-private: %s",
 854              name_and_sig_as_C_string());
 855   }
 856 #endif
 857   assert(valid_vtable_index() || valid_itable_index(), "method must be linked before we ask this question");
 858   return vtable_index() == nonvirtual_vtable_index;
 859 }
 860 
 861 bool Method::can_be_statically_bound() const {
 862   return can_be_statically_bound(method_holder()->access_flags());
 863 }
 864 
 865 bool Method::can_be_statically_bound(InstanceKlass* context) const {
 866   return (method_holder() == context) && can_be_statically_bound();
 867 }
 868 
 869 /**
 870  *  Returns false if this is one of specially treated methods for
 871  *  which we have to provide stack trace in throw in compiled code.
 872  *  Returns true otherwise.
 873  */
 874 bool Method::can_omit_stack_trace() {
 875   if (klass_name() == vmSymbols::sun_invoke_util_ValueConversions()) {
 876     return false; // All methods in sun.invoke.util.ValueConversions
 877   }
 878   return true;
 879 }
 880 
 881 bool Method::is_accessor() const {
 882   return is_getter() || is_setter();
 883 }
 884 
 885 bool Method::is_getter() const {
 886   if (code_size() != 5) return false;
 887   if (size_of_parameters() != 1) return false;
 888   if (java_code_at(0) != Bytecodes::_aload_0)  return false;
 889   if (java_code_at(1) != Bytecodes::_getfield) return false;
 890   switch (java_code_at(4)) {
 891     case Bytecodes::_ireturn:
 892     case Bytecodes::_lreturn:
 893     case Bytecodes::_freturn:
 894     case Bytecodes::_dreturn:
 895     case Bytecodes::_areturn:
 896       break;
 897     default:
 898       return false;
 899   }
 900   return true;
 901 }
 902 
 903 bool Method::is_setter() const {
 904   if (code_size() != 6) return false;
 905   if (java_code_at(0) != Bytecodes::_aload_0) return false;
 906   switch (java_code_at(1)) {
 907     case Bytecodes::_iload_1:
 908     case Bytecodes::_aload_1:
 909     case Bytecodes::_fload_1:
 910       if (size_of_parameters() != 2) return false;
 911       break;
 912     case Bytecodes::_dload_1:
 913     case Bytecodes::_lload_1:
 914       if (size_of_parameters() != 3) return false;
 915       break;
 916     default:
 917       return false;
 918   }
 919   if (java_code_at(2) != Bytecodes::_putfield) return false;
 920   if (java_code_at(5) != Bytecodes::_return)   return false;
 921   return true;
 922 }
 923 
 924 bool Method::is_constant_getter() const {
 925   int last_index = code_size() - 1;
 926   // Check if the first 1-3 bytecodes are a constant push
 927   // and the last bytecode is a return.
 928   return (2 <= code_size() && code_size() <= 4 &&
 929           Bytecodes::is_const(java_code_at(0)) &&
 930           Bytecodes::length_for(java_code_at(0)) == last_index &&
 931           Bytecodes::is_return(java_code_at(last_index)));
 932 }
 933 
 934 bool Method::has_valid_initializer_flags() const {
 935   return (is_static() ||
 936           method_holder()->major_version() < 51);
 937 }
 938 
 939 bool Method::is_static_initializer() const {
 940   // For classfiles version 51 or greater, ensure that the clinit method is
 941   // static.  Non-static methods with the name "<clinit>" are not static
 942   // initializers. (older classfiles exempted for backward compatibility)
 943   return name() == vmSymbols::class_initializer_name() &&
 944          has_valid_initializer_flags();
 945 }
 946 
 947 bool Method::is_object_initializer() const {
 948    return name() == vmSymbols::object_initializer_name();
 949 }
 950 
 951 bool Method::needs_clinit_barrier() const {
 952   return is_static() && !method_holder()->is_initialized();
 953 }
 954 
 955 bool Method::code_has_clinit_barriers() const {
 956   nmethod* nm = code();
 957   return (nm != nullptr) && nm->has_clinit_barriers();
 958 }
 959 
 960 bool Method::is_object_wait0() const {
 961   return klass_name() == vmSymbols::java_lang_Object()
 962          && name() == vmSymbols::wait_name();
 963 }
 964 
 965 objArrayHandle Method::resolved_checked_exceptions_impl(Method* method, TRAPS) {
 966   int length = method->checked_exceptions_length();
 967   if (length == 0) {  // common case
 968     return objArrayHandle(THREAD, Universe::the_empty_class_array());
 969   } else {
 970     methodHandle h_this(THREAD, method);
 971     objArrayOop m_oop = oopFactory::new_objArray(vmClasses::Class_klass(), length, CHECK_(objArrayHandle()));
 972     objArrayHandle mirrors (THREAD, m_oop);
 973     for (int i = 0; i < length; i++) {
 974       CheckedExceptionElement* table = h_this->checked_exceptions_start(); // recompute on each iteration, not gc safe
 975       Klass* k = h_this->constants()->klass_at(table[i].class_cp_index, CHECK_(objArrayHandle()));
 976       if (log_is_enabled(Warning, exceptions) &&
 977           !k->is_subclass_of(vmClasses::Throwable_klass())) {
 978         ResourceMark rm(THREAD);
 979         log_warning(exceptions)(
 980           "Class %s in throws clause of method %s is not a subtype of class java.lang.Throwable",
 981           k->external_name(), method->external_name());
 982       }
 983       mirrors->obj_at_put(i, k->java_mirror());
 984     }
 985     return mirrors;
 986   }
 987 };
 988 
 989 
 990 int Method::line_number_from_bci(int bci) const {
 991   int best_bci  =  0;
 992   int best_line = -1;
 993   if (bci == SynchronizationEntryBCI) bci = 0;
 994   if (0 <= bci && bci < code_size() && has_linenumber_table()) {
 995     // The line numbers are a short array of 2-tuples [start_pc, line_number].
 996     // Not necessarily sorted and not necessarily one-to-one.
 997     CompressedLineNumberReadStream stream(compressed_linenumber_table());
 998     while (stream.read_pair()) {
 999       if (stream.bci() == bci) {
1000         // perfect match
1001         return stream.line();
1002       } else {
1003         // update best_bci/line
1004         if (stream.bci() < bci && stream.bci() >= best_bci) {
1005           best_bci  = stream.bci();
1006           best_line = stream.line();
1007         }
1008       }
1009     }
1010   }
1011   return best_line;
1012 }
1013 
1014 
1015 bool Method::is_klass_loaded_by_klass_index(int klass_index) const {
1016   if( constants()->tag_at(klass_index).is_unresolved_klass() ) {
1017     Thread *thread = Thread::current();
1018     Symbol* klass_name = constants()->klass_name_at(klass_index);
1019     Handle loader(thread, method_holder()->class_loader());
1020     return SystemDictionary::find_instance_klass(thread, klass_name, loader) != nullptr;
1021   } else {
1022     return true;
1023   }
1024 }
1025 
1026 
1027 bool Method::is_klass_loaded(int refinfo_index, Bytecodes::Code bc, bool must_be_resolved) const {
1028   int klass_index = constants()->klass_ref_index_at(refinfo_index, bc);
1029   if (must_be_resolved) {
1030     // Make sure klass is resolved in constantpool.
1031     if (constants()->tag_at(klass_index).is_unresolved_klass()) return false;
1032   }
1033   return is_klass_loaded_by_klass_index(klass_index);
1034 }
1035 
1036 
1037 void Method::set_native_function(address function, bool post_event_flag) {
1038   assert(function != nullptr, "use clear_native_function to unregister natives");
1039   assert(!is_special_native_intrinsic() || function == SharedRuntime::native_method_throw_unsatisfied_link_error_entry(), "");
1040   address* native_function = native_function_addr();
1041 
1042   // We can see racers trying to place the same native function into place. Once
1043   // is plenty.
1044   address current = *native_function;
1045   if (current == function) return;
1046   if (post_event_flag && JvmtiExport::should_post_native_method_bind() &&
1047       function != nullptr) {
1048     // native_method_throw_unsatisfied_link_error_entry() should only
1049     // be passed when post_event_flag is false.
1050     assert(function !=
1051       SharedRuntime::native_method_throw_unsatisfied_link_error_entry(),
1052       "post_event_flag mismatch");
1053 
1054     // post the bind event, and possible change the bind function
1055     JvmtiExport::post_native_method_bind(this, &function);
1056   }
1057   *native_function = function;
1058   // This function can be called more than once. We must make sure that we always
1059   // use the latest registered method -> check if a stub already has been generated.
1060   // If so, we have to make it not_entrant.
1061   nmethod* nm = code(); // Put it into local variable to guard against concurrent updates
1062   if (nm != nullptr) {
1063     nm->make_not_entrant();
1064   }
1065 }
1066 
1067 
1068 bool Method::has_native_function() const {
1069   if (is_special_native_intrinsic())
1070     return false;  // special-cased in SharedRuntime::generate_native_wrapper
1071   address func = native_function();
1072   return (func != nullptr && func != SharedRuntime::native_method_throw_unsatisfied_link_error_entry());
1073 }
1074 
1075 
1076 void Method::clear_native_function() {
1077   // Note: is_method_handle_intrinsic() is allowed here.
1078   set_native_function(
1079     SharedRuntime::native_method_throw_unsatisfied_link_error_entry(),
1080     !native_bind_event_is_interesting);
1081   this->unlink_code();
1082 }
1083 
1084 
1085 void Method::set_signature_handler(address handler) {
1086   address* signature_handler =  signature_handler_addr();
1087   *signature_handler = handler;
1088 }
1089 
1090 
1091 void Method::print_made_not_compilable(int comp_level, bool is_osr, bool report, const char* reason) {
1092   assert(reason != nullptr, "must provide a reason");
1093   if (PrintCompilation && report) {
1094     ttyLocker ttyl;
1095     tty->print("made not %scompilable on ", is_osr ? "OSR " : "");
1096     if (comp_level == CompLevel_all) {
1097       tty->print("all levels ");
1098     } else {
1099       tty->print("level %d ", comp_level);
1100     }
1101     this->print_short_name(tty);
1102     int size = this->code_size();
1103     if (size > 0) {
1104       tty->print(" (%d bytes)", size);
1105     }
1106     if (reason != nullptr) {
1107       tty->print("   %s", reason);
1108     }
1109     tty->cr();
1110   }
1111   if ((TraceDeoptimization || LogCompilation) && (xtty != nullptr)) {
1112     ttyLocker ttyl;
1113     xtty->begin_elem("make_not_compilable thread='%zu' osr='%d' level='%d'",
1114                      os::current_thread_id(), is_osr, comp_level);
1115     if (reason != nullptr) {
1116       xtty->print(" reason=\'%s\'", reason);
1117     }
1118     xtty->method(this);
1119     xtty->stamp();
1120     xtty->end_elem();
1121   }
1122 }
1123 
1124 bool Method::is_always_compilable() const {
1125   // Generated adapters must be compiled
1126   if (is_special_native_intrinsic() && is_synthetic()) {
1127     assert(!is_not_c1_compilable(), "sanity check");
1128     assert(!is_not_c2_compilable(), "sanity check");
1129     return true;
1130   }
1131 
1132   return false;
1133 }
1134 
1135 bool Method::is_not_compilable(int comp_level) const {
1136   if (number_of_breakpoints() > 0)
1137     return true;
1138   if (is_always_compilable())
1139     return false;
1140   if (comp_level == CompLevel_any)
1141     return is_not_c1_compilable() && is_not_c2_compilable();
1142   if (is_c1_compile(comp_level))
1143     return is_not_c1_compilable();
1144   if (is_c2_compile(comp_level))
1145     return is_not_c2_compilable();
1146   return false;
1147 }
1148 
1149 // call this when compiler finds that this method is not compilable
1150 void Method::set_not_compilable(const char* reason, int comp_level, bool report) {
1151   if (is_always_compilable()) {
1152     // Don't mark a method which should be always compilable
1153     return;
1154   }
1155   print_made_not_compilable(comp_level, /*is_osr*/ false, report, reason);
1156   if (comp_level == CompLevel_all) {
1157     set_is_not_c1_compilable();
1158     set_is_not_c2_compilable();
1159   } else {
1160     if (is_c1_compile(comp_level))
1161       set_is_not_c1_compilable();
1162     if (is_c2_compile(comp_level))
1163       set_is_not_c2_compilable();
1164   }
1165   assert(!CompilationPolicy::can_be_compiled(methodHandle(Thread::current(), this), comp_level), "sanity check");
1166 }
1167 
1168 bool Method::is_not_osr_compilable(int comp_level) const {
1169   if (is_not_compilable(comp_level))
1170     return true;
1171   if (comp_level == CompLevel_any)
1172     return is_not_c1_osr_compilable() && is_not_c2_osr_compilable();
1173   if (is_c1_compile(comp_level))
1174     return is_not_c1_osr_compilable();
1175   if (is_c2_compile(comp_level))
1176     return is_not_c2_osr_compilable();
1177   return false;
1178 }
1179 
1180 void Method::set_not_osr_compilable(const char* reason, int comp_level, bool report) {
1181   print_made_not_compilable(comp_level, /*is_osr*/ true, report, reason);
1182   if (comp_level == CompLevel_all) {
1183     set_is_not_c1_osr_compilable();
1184     set_is_not_c2_osr_compilable();
1185   } else {
1186     if (is_c1_compile(comp_level))
1187       set_is_not_c1_osr_compilable();
1188     if (is_c2_compile(comp_level))
1189       set_is_not_c2_osr_compilable();
1190   }
1191   assert(!CompilationPolicy::can_be_osr_compiled(methodHandle(Thread::current(), this), comp_level), "sanity check");
1192 }
1193 
1194 // Revert to using the interpreter and clear out the nmethod
1195 void Method::clear_code() {
1196   // this may be null if c2i adapters have not been made yet
1197   // Only should happen at allocate time.
1198   if (adapter() == nullptr) {
1199     _from_compiled_entry    = nullptr;
1200   } else {
1201     _from_compiled_entry    = adapter()->get_c2i_entry();
1202   }
1203   OrderAccess::storestore();
1204   _from_interpreted_entry = _i2i_entry;
1205   OrderAccess::storestore();
1206   _code = nullptr;
1207 }
1208 
1209 void Method::unlink_code(nmethod *compare) {
1210   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
1211   // We need to check if either the _code or _from_compiled_code_entry_point
1212   // refer to this nmethod because there is a race in setting these two fields
1213   // in Method* as seen in bugid 4947125.
1214   if (code() == compare ||
1215       from_compiled_entry() == compare->verified_entry_point()) {
1216     clear_code();
1217   }
1218 }
1219 
1220 void Method::unlink_code() {
1221   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
1222   clear_code();
1223 }
1224 
1225 #if INCLUDE_CDS
1226 // Called by class data sharing to remove any entry points (which are not shared)
1227 void Method::unlink_method() {
1228   assert(CDSConfig::is_dumping_archive(), "sanity");
1229   _code = nullptr;
1230   if (!CDSConfig::is_dumping_adapters() || AdapterHandlerLibrary::is_abstract_method_adapter(_adapter)) {
1231     _adapter = nullptr;
1232   }
1233   _i2i_entry = nullptr;
1234   _from_compiled_entry = nullptr;
1235   _from_interpreted_entry = nullptr;
1236 
1237   if (is_native()) {
1238     *native_function_addr() = nullptr;
1239     set_signature_handler(nullptr);
1240   }
1241   NOT_PRODUCT(set_compiled_invocation_count(0);)
1242 
1243   clear_method_data();
1244   clear_method_counters();
1245   clear_is_not_c1_compilable();
1246   clear_is_not_c1_osr_compilable();
1247   clear_is_not_c2_compilable();
1248   clear_is_not_c2_osr_compilable();
1249   clear_queued_for_compilation();
1250   set_pending_queue_processed(false);
1251   remove_unshareable_flags();
1252 }
1253 
1254 void Method::remove_unshareable_flags() {
1255   // clear all the flags that shouldn't be in the archived version
1256   assert(!is_old(), "must be");
1257   assert(!is_obsolete(), "must be");
1258   assert(!is_deleted(), "must be");
1259 
1260   set_is_prefixed_native(false);
1261   set_queued_for_compilation(false);
1262   set_pending_queue_processed(false);
1263   set_is_not_c2_compilable(false);
1264   set_is_not_c1_compilable(false);
1265   set_is_not_c2_osr_compilable(false);
1266   set_on_stack_flag(false);
1267   set_has_upcall_on_method_entry(false);
1268   set_has_upcall_on_method_exit(false);
1269 }
1270 #endif
1271 
1272 // Called when the method_holder is getting linked. Setup entrypoints so the method
1273 // is ready to be called from interpreter, compiler, and vtables.
1274 void Method::link_method(const methodHandle& h_method, TRAPS) {
1275   if (log_is_enabled(Info, perf, class, link)) {
1276     ClassLoader::perf_ik_link_methods_count()->inc();
1277   }
1278 
1279   // If the code cache is full, we may reenter this function for the
1280   // leftover methods that weren't linked.
1281   if (adapter() != nullptr && !adapter()->is_shared()) {
1282     return;
1283   }
1284   assert( _code == nullptr, "nothing compiled yet" );
1285 
1286   // Setup interpreter entrypoint
1287   assert(this == h_method(), "wrong h_method()" );
1288 
1289   assert(adapter() == nullptr || adapter()->is_linked(), "init'd to null or restored from cache");
1290   address entry = Interpreter::entry_for_method(h_method);
1291   assert(entry != nullptr, "interpreter entry must be non-null");
1292   // Sets both _i2i_entry and _from_interpreted_entry
1293   set_interpreter_entry(entry);
1294 
1295   // Don't overwrite already registered native entries.
1296   if (is_native() && !has_native_function()) {
1297     set_native_function(
1298       SharedRuntime::native_method_throw_unsatisfied_link_error_entry(),
1299       !native_bind_event_is_interesting);
1300   }
1301 
1302   // Setup compiler entrypoint.  This is made eagerly, so we do not need
1303   // special handling of vtables.  An alternative is to make adapters more
1304   // lazily by calling make_adapter() from from_compiled_entry() for the
1305   // normal calls.  For vtable calls life gets more complicated.  When a
1306   // call-site goes mega-morphic we need adapters in all methods which can be
1307   // called from the vtable.  We need adapters on such methods that get loaded
1308   // later.  Ditto for mega-morphic itable calls.  If this proves to be a
1309   // problem we'll make these lazily later.
1310   if (_adapter == nullptr) {
1311     (void) make_adapters(h_method, CHECK);
1312   }
1313 
1314   // ONLY USE the h_method now as make_adapter may have blocked
1315 
1316   if (h_method->is_continuation_native_intrinsic()) {
1317     _from_interpreted_entry = nullptr;
1318     _from_compiled_entry = nullptr;
1319     _i2i_entry = nullptr;
1320     if (Continuations::enabled()) {
1321       assert(!Threads::is_vm_complete(), "should only be called during vm init");
1322       AdapterHandlerLibrary::create_native_wrapper(h_method);
1323       if (!h_method->has_compiled_code()) {
1324         THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), "Initial size of CodeCache is too small");
1325       }
1326       assert(_from_interpreted_entry == get_i2c_entry(), "invariant");
1327     }
1328   }
1329   if (_preload_code != nullptr) {
1330     MutexLocker ml(NMethodState_lock, Mutex::_no_safepoint_check_flag);
1331     set_code(h_method, _preload_code);
1332     assert(((nmethod*)_preload_code)->scc_entry() == _scc_entry, "sanity");
1333   }
1334 }
1335 
1336 address Method::make_adapters(const methodHandle& mh, TRAPS) {
1337   PerfTraceElapsedTime timer(ClassLoader::perf_method_adapters_time());
1338 
1339   // Adapters for compiled code are made eagerly here.  They are fairly
1340   // small (generally < 100 bytes) and quick to make (and cached and shared)
1341   // so making them eagerly shouldn't be too expensive.
1342   AdapterHandlerEntry* adapter = AdapterHandlerLibrary::get_adapter(mh);
1343   if (adapter == nullptr ) {
1344     if (!is_init_completed()) {
1345       // Don't throw exceptions during VM initialization because java.lang.* classes
1346       // might not have been initialized, causing problems when constructing the
1347       // Java exception object.
1348       vm_exit_during_initialization("Out of space in CodeCache for adapters");
1349     } else {
1350       THROW_MSG_NULL(vmSymbols::java_lang_OutOfMemoryError(), "Out of space in CodeCache for adapters");
1351     }
1352   }
1353 
1354   mh->set_adapter_entry(adapter);
1355   mh->_from_compiled_entry = adapter->get_c2i_entry();
1356   return adapter->get_c2i_entry();
1357 }
1358 
1359 // The verified_code_entry() must be called when a invoke is resolved
1360 // on this method.
1361 
1362 // It returns the compiled code entry point, after asserting not null.
1363 // This function is called after potential safepoints so that nmethod
1364 // or adapter that it points to is still live and valid.
1365 // This function must not hit a safepoint!
1366 address Method::verified_code_entry() {
1367   debug_only(NoSafepointVerifier nsv;)
1368   assert(_from_compiled_entry != nullptr, "must be set");
1369   return _from_compiled_entry;
1370 }
1371 
1372 // Check that if an nmethod ref exists, it has a backlink to this or no backlink at all
1373 // (could be racing a deopt).
1374 // Not inline to avoid circular ref.
1375 bool Method::check_code() const {
1376   // cached in a register or local.  There's a race on the value of the field.
1377   nmethod *code = Atomic::load_acquire(&_code);
1378   return code == nullptr || (code->method() == nullptr) || (code->method() == (Method*)this && !code->is_osr_method());
1379 }
1380 
1381 // Install compiled code.  Instantly it can execute.
1382 void Method::set_code(const methodHandle& mh, nmethod *code) {
1383   assert_lock_strong(NMethodState_lock);
1384   assert( code, "use clear_code to remove code" );
1385   assert( mh->check_code(), "" );
1386 
1387   guarantee(mh->adapter() != nullptr, "Adapter blob must already exist!");
1388 
1389   // These writes must happen in this order, because the interpreter will
1390   // directly jump to from_interpreted_entry which jumps to an i2c adapter
1391   // which jumps to _from_compiled_entry.
1392   mh->_code = code;             // Assign before allowing compiled code to exec
1393 
1394   int comp_level = code->comp_level();
1395   // In theory there could be a race here. In practice it is unlikely
1396   // and not worth worrying about.
1397   if (comp_level > mh->highest_comp_level()) {
1398     mh->set_highest_comp_level(comp_level);
1399   }
1400 
1401   OrderAccess::storestore();
1402   mh->_from_compiled_entry = code->verified_entry_point();
1403   OrderAccess::storestore();
1404 
1405   if (mh->is_continuation_native_intrinsic()) {
1406     assert(mh->_from_interpreted_entry == nullptr, "initialized incorrectly"); // see link_method
1407 
1408     if (mh->is_continuation_enter_intrinsic()) {
1409       // This is the entry used when we're in interpreter-only mode; see InterpreterMacroAssembler::jump_from_interpreted
1410       mh->_i2i_entry = ContinuationEntry::interpreted_entry();
1411     } else if (mh->is_continuation_yield_intrinsic()) {
1412       mh->_i2i_entry = mh->get_i2c_entry();
1413     } else {
1414       guarantee(false, "Unknown Continuation native intrinsic");
1415     }
1416     // This must come last, as it is what's tested in LinkResolver::resolve_static_call
1417     Atomic::release_store(&mh->_from_interpreted_entry , mh->get_i2c_entry());
1418   } else if (!mh->is_method_handle_intrinsic()) {
1419     // Instantly compiled code can execute.
1420     mh->_from_interpreted_entry = mh->get_i2c_entry();
1421   }
1422 }
1423 
1424 
1425 bool Method::is_overridden_in(Klass* k) const {
1426   InstanceKlass* ik = InstanceKlass::cast(k);
1427 
1428   if (ik->is_interface()) return false;
1429 
1430   // If method is an interface, we skip it - except if it
1431   // is a miranda method
1432   if (method_holder()->is_interface()) {
1433     // Check that method is not a miranda method
1434     if (ik->lookup_method(name(), signature()) == nullptr) {
1435       // No implementation exist - so miranda method
1436       return false;
1437     }
1438     return true;
1439   }
1440 
1441   assert(ik->is_subclass_of(method_holder()), "should be subklass");
1442   if (!has_vtable_index()) {
1443     return false;
1444   } else {
1445     Method* vt_m = ik->method_at_vtable(vtable_index());
1446     return vt_m != this;
1447   }
1448 }
1449 
1450 
1451 // give advice about whether this Method* should be cached or not
1452 bool Method::should_not_be_cached() const {
1453   if (is_old()) {
1454     // This method has been redefined. It is either EMCP or obsolete
1455     // and we don't want to cache it because that would pin the method
1456     // down and prevent it from being collectible if and when it
1457     // finishes executing.
1458     return true;
1459   }
1460 
1461   // caching this method should be just fine
1462   return false;
1463 }
1464 
1465 
1466 /**
1467  *  Returns true if this is one of the specially treated methods for
1468  *  security related stack walks (like Reflection.getCallerClass).
1469  */
1470 bool Method::is_ignored_by_security_stack_walk() const {
1471   if (intrinsic_id() == vmIntrinsics::_invoke) {
1472     // This is Method.invoke() -- ignore it
1473     return true;
1474   }
1475   if (method_holder()->is_subclass_of(vmClasses::reflect_MethodAccessorImpl_klass())) {
1476     // This is an auxiliary frame -- ignore it
1477     return true;
1478   }
1479   if (is_method_handle_intrinsic() || is_compiled_lambda_form()) {
1480     // This is an internal adapter frame for method handles -- ignore it
1481     return true;
1482   }
1483   return false;
1484 }
1485 
1486 
1487 // Constant pool structure for invoke methods:
1488 enum {
1489   _imcp_invoke_name = 1,        // utf8: 'invokeExact', etc.
1490   _imcp_invoke_signature,       // utf8: (variable Symbol*)
1491   _imcp_limit
1492 };
1493 
1494 // Test if this method is an MH adapter frame generated by Java code.
1495 // Cf. java/lang/invoke/InvokerBytecodeGenerator
1496 bool Method::is_compiled_lambda_form() const {
1497   return intrinsic_id() == vmIntrinsics::_compiledLambdaForm;
1498 }
1499 
1500 // Test if this method is an internal MH primitive method.
1501 bool Method::is_method_handle_intrinsic() const {
1502   vmIntrinsics::ID iid = intrinsic_id();
1503   return (MethodHandles::is_signature_polymorphic(iid) &&
1504           MethodHandles::is_signature_polymorphic_intrinsic(iid));
1505 }
1506 
1507 bool Method::has_member_arg() const {
1508   vmIntrinsics::ID iid = intrinsic_id();
1509   return (MethodHandles::is_signature_polymorphic(iid) &&
1510           MethodHandles::has_member_arg(iid));
1511 }
1512 
1513 // Make an instance of a signature-polymorphic internal MH primitive.
1514 methodHandle Method::make_method_handle_intrinsic(vmIntrinsics::ID iid,
1515                                                          Symbol* signature,
1516                                                          TRAPS) {
1517   ResourceMark rm(THREAD);
1518   methodHandle empty;
1519 
1520   InstanceKlass* holder = vmClasses::MethodHandle_klass();
1521   Symbol* name = MethodHandles::signature_polymorphic_intrinsic_name(iid);
1522   assert(iid == MethodHandles::signature_polymorphic_name_id(name), "");
1523 
1524   log_info(methodhandles)("make_method_handle_intrinsic MH.%s%s", name->as_C_string(), signature->as_C_string());
1525 
1526   // invariant:   cp->symbol_at_put is preceded by a refcount increment (more usually a lookup)
1527   name->increment_refcount();
1528   signature->increment_refcount();
1529 
1530   int cp_length = _imcp_limit;
1531   ClassLoaderData* loader_data = holder->class_loader_data();
1532   constantPoolHandle cp;
1533   {
1534     ConstantPool* cp_oop = ConstantPool::allocate(loader_data, cp_length, CHECK_(empty));
1535     cp = constantPoolHandle(THREAD, cp_oop);
1536   }
1537   cp->copy_fields(holder->constants());
1538   cp->set_pool_holder(holder);
1539   cp->symbol_at_put(_imcp_invoke_name,       name);
1540   cp->symbol_at_put(_imcp_invoke_signature,  signature);
1541   cp->set_has_preresolution();
1542   cp->set_is_for_method_handle_intrinsic();
1543 
1544   // decide on access bits:  public or not?
1545   u2 flags_bits = (JVM_ACC_NATIVE | JVM_ACC_SYNTHETIC | JVM_ACC_FINAL);
1546   bool must_be_static = MethodHandles::is_signature_polymorphic_static(iid);
1547   if (must_be_static)  flags_bits |= JVM_ACC_STATIC;
1548   assert((flags_bits & JVM_ACC_PUBLIC) == 0, "do not expose these methods");
1549 
1550   methodHandle m;
1551   {
1552     InlineTableSizes sizes;
1553     Method* m_oop = Method::allocate(loader_data, 0,
1554                                      accessFlags_from(flags_bits), &sizes,
1555                                      ConstMethod::NORMAL,
1556                                      name,
1557                                      CHECK_(empty));
1558     m = methodHandle(THREAD, m_oop);
1559   }
1560   m->set_constants(cp());
1561   m->set_name_index(_imcp_invoke_name);
1562   m->set_signature_index(_imcp_invoke_signature);
1563   assert(MethodHandles::is_signature_polymorphic_name(m->name()), "");
1564   assert(m->signature() == signature, "");
1565   m->constMethod()->compute_from_signature(signature, must_be_static);
1566   m->init_intrinsic_id(klass_id_for_intrinsics(m->method_holder()));
1567   assert(m->is_method_handle_intrinsic(), "");
1568 #ifdef ASSERT
1569   if (!MethodHandles::is_signature_polymorphic(m->intrinsic_id()))  m->print();
1570   assert(MethodHandles::is_signature_polymorphic(m->intrinsic_id()), "must be an invoker");
1571   assert(m->intrinsic_id() == iid, "correctly predicted iid");
1572 #endif //ASSERT
1573 
1574   // Finally, set up its entry points.
1575   assert(m->can_be_statically_bound(), "");
1576   m->set_vtable_index(Method::nonvirtual_vtable_index);
1577   m->link_method(m, CHECK_(empty));
1578 
1579   if (iid == vmIntrinsics::_linkToNative) {
1580     m->set_interpreter_entry(m->adapter()->get_i2c_entry());
1581   }
1582   if (log_is_enabled(Debug, methodhandles)) {
1583     LogTarget(Debug, methodhandles) lt;
1584     LogStream ls(lt);
1585     m->print_on(&ls);
1586   }
1587 
1588   return m;
1589 }
1590 
1591 #if INCLUDE_CDS
1592 void Method::restore_archived_method_handle_intrinsic(methodHandle m, TRAPS) {
1593   m->restore_adapter(CHECK);
1594   if (m->adapter() != nullptr) {
1595     m->adapter()->restore_unshareable_info(CHECK);
1596     m->set_from_compiled_entry(m->adapter()->get_c2i_entry());
1597   }
1598   m->link_method(m, CHECK);
1599 
1600   if (m->intrinsic_id() == vmIntrinsics::_linkToNative) {
1601     m->set_interpreter_entry(m->adapter()->get_i2c_entry());
1602   }
1603 }
1604 #endif
1605 
1606 Klass* Method::check_non_bcp_klass(Klass* klass) {
1607   if (klass != nullptr && klass->class_loader() != nullptr) {
1608     if (klass->is_objArray_klass())
1609       klass = ObjArrayKlass::cast(klass)->bottom_klass();
1610     return klass;
1611   }
1612   return nullptr;
1613 }
1614 
1615 
1616 methodHandle Method::clone_with_new_data(const methodHandle& m, u_char* new_code, int new_code_length,
1617                                                 u_char* new_compressed_linenumber_table, int new_compressed_linenumber_size, TRAPS) {
1618   // Code below does not work for native methods - they should never get rewritten anyway
1619   assert(!m->is_native(), "cannot rewrite native methods");
1620   // Allocate new Method*
1621   AccessFlags flags = m->access_flags();
1622 
1623   ConstMethod* cm = m->constMethod();
1624   int checked_exceptions_len = cm->checked_exceptions_length();
1625   int localvariable_len = cm->localvariable_table_length();
1626   int exception_table_len = cm->exception_table_length();
1627   int method_parameters_len = cm->method_parameters_length();
1628   int method_annotations_len = cm->method_annotations_length();
1629   int parameter_annotations_len = cm->parameter_annotations_length();
1630   int type_annotations_len = cm->type_annotations_length();
1631   int default_annotations_len = cm->default_annotations_length();
1632 
1633   InlineTableSizes sizes(
1634       localvariable_len,
1635       new_compressed_linenumber_size,
1636       exception_table_len,
1637       checked_exceptions_len,
1638       method_parameters_len,
1639       cm->generic_signature_index(),
1640       method_annotations_len,
1641       parameter_annotations_len,
1642       type_annotations_len,
1643       default_annotations_len,
1644       0);
1645 
1646   ClassLoaderData* loader_data = m->method_holder()->class_loader_data();
1647   Method* newm_oop = Method::allocate(loader_data,
1648                                       new_code_length,
1649                                       flags,
1650                                       &sizes,
1651                                       m->method_type(),
1652                                       m->name(),
1653                                       CHECK_(methodHandle()));
1654   methodHandle newm (THREAD, newm_oop);
1655 
1656   // Create a shallow copy of Method part, but be careful to preserve the new ConstMethod*
1657   ConstMethod* newcm = newm->constMethod();
1658   int new_const_method_size = newm->constMethod()->size();
1659 
1660   // This works because the source and target are both Methods. Some compilers
1661   // (e.g., clang) complain that the target vtable pointer will be stomped,
1662   // so cast away newm()'s and m()'s Methodness.
1663   memcpy((void*)newm(), (void*)m(), sizeof(Method));
1664 
1665   // Create shallow copy of ConstMethod.
1666   memcpy(newcm, m->constMethod(), sizeof(ConstMethod));
1667 
1668   // Reset correct method/const method, method size, and parameter info
1669   newm->set_constMethod(newcm);
1670   newm->constMethod()->set_code_size(new_code_length);
1671   newm->constMethod()->set_constMethod_size(new_const_method_size);
1672   assert(newm->code_size() == new_code_length, "check");
1673   assert(newm->method_parameters_length() == method_parameters_len, "check");
1674   assert(newm->checked_exceptions_length() == checked_exceptions_len, "check");
1675   assert(newm->exception_table_length() == exception_table_len, "check");
1676   assert(newm->localvariable_table_length() == localvariable_len, "check");
1677   // Copy new byte codes
1678   memcpy(newm->code_base(), new_code, new_code_length);
1679   // Copy line number table
1680   if (new_compressed_linenumber_size > 0) {
1681     memcpy(newm->compressed_linenumber_table(),
1682            new_compressed_linenumber_table,
1683            new_compressed_linenumber_size);
1684   }
1685   // Copy method_parameters
1686   if (method_parameters_len > 0) {
1687     memcpy(newm->method_parameters_start(),
1688            m->method_parameters_start(),
1689            method_parameters_len * sizeof(MethodParametersElement));
1690   }
1691   // Copy checked_exceptions
1692   if (checked_exceptions_len > 0) {
1693     memcpy(newm->checked_exceptions_start(),
1694            m->checked_exceptions_start(),
1695            checked_exceptions_len * sizeof(CheckedExceptionElement));
1696   }
1697   // Copy exception table
1698   if (exception_table_len > 0) {
1699     memcpy(newm->exception_table_start(),
1700            m->exception_table_start(),
1701            exception_table_len * sizeof(ExceptionTableElement));
1702   }
1703   // Copy local variable number table
1704   if (localvariable_len > 0) {
1705     memcpy(newm->localvariable_table_start(),
1706            m->localvariable_table_start(),
1707            localvariable_len * sizeof(LocalVariableTableElement));
1708   }
1709   // Copy stackmap table
1710   if (m->has_stackmap_table()) {
1711     int code_attribute_length = m->stackmap_data()->length();
1712     Array<u1>* stackmap_data =
1713       MetadataFactory::new_array<u1>(loader_data, code_attribute_length, 0, CHECK_(methodHandle()));
1714     memcpy((void*)stackmap_data->adr_at(0),
1715            (void*)m->stackmap_data()->adr_at(0), code_attribute_length);
1716     newm->set_stackmap_data(stackmap_data);
1717   }
1718 
1719   // copy annotations over to new method
1720   newcm->copy_annotations_from(loader_data, cm, CHECK_(methodHandle()));
1721   return newm;
1722 }
1723 
1724 vmSymbolID Method::klass_id_for_intrinsics(const Klass* holder) {
1725   // if loader is not the default loader (i.e., non-null), we can't know the intrinsics
1726   // because we are not loading from core libraries
1727   // exception: the AES intrinsics come from lib/ext/sunjce_provider.jar
1728   // which does not use the class default class loader so we check for its loader here
1729   const InstanceKlass* ik = InstanceKlass::cast(holder);
1730   if ((ik->class_loader() != nullptr) && !SystemDictionary::is_platform_class_loader(ik->class_loader())) {
1731     return vmSymbolID::NO_SID;   // regardless of name, no intrinsics here
1732   }
1733 
1734   // see if the klass name is well-known:
1735   Symbol* klass_name = ik->name();
1736   vmSymbolID id = vmSymbols::find_sid(klass_name);
1737   if (id != vmSymbolID::NO_SID && vmIntrinsics::class_has_intrinsics(id)) {
1738     return id;
1739   } else {
1740     return vmSymbolID::NO_SID;
1741   }
1742 }
1743 
1744 void Method::init_intrinsic_id(vmSymbolID klass_id) {
1745   assert(_intrinsic_id == static_cast<int>(vmIntrinsics::_none), "do this just once");
1746   const uintptr_t max_id_uint = right_n_bits((int)(sizeof(_intrinsic_id) * BitsPerByte));
1747   assert((uintptr_t)vmIntrinsics::ID_LIMIT <= max_id_uint, "else fix size");
1748   assert(intrinsic_id_size_in_bytes() == sizeof(_intrinsic_id), "");
1749 
1750   // the klass name is well-known:
1751   assert(klass_id == klass_id_for_intrinsics(method_holder()), "must be");
1752   assert(klass_id != vmSymbolID::NO_SID, "caller responsibility");
1753 
1754   // ditto for method and signature:
1755   vmSymbolID name_id = vmSymbols::find_sid(name());
1756   if (klass_id != VM_SYMBOL_ENUM_NAME(java_lang_invoke_MethodHandle)
1757       && klass_id != VM_SYMBOL_ENUM_NAME(java_lang_invoke_VarHandle)
1758       && name_id == vmSymbolID::NO_SID) {
1759     return;
1760   }
1761   vmSymbolID sig_id = vmSymbols::find_sid(signature());
1762   if (klass_id != VM_SYMBOL_ENUM_NAME(java_lang_invoke_MethodHandle)
1763       && klass_id != VM_SYMBOL_ENUM_NAME(java_lang_invoke_VarHandle)
1764       && sig_id == vmSymbolID::NO_SID) {
1765     return;
1766   }
1767 
1768   u2 flags = access_flags().as_method_flags();
1769   vmIntrinsics::ID id = vmIntrinsics::find_id(klass_id, name_id, sig_id, flags);
1770   if (id != vmIntrinsics::_none) {
1771     set_intrinsic_id(id);
1772     if (id == vmIntrinsics::_Class_cast) {
1773       // Even if the intrinsic is rejected, we want to inline this simple method.
1774       set_force_inline();
1775     }
1776     return;
1777   }
1778 
1779   // A few slightly irregular cases:
1780   switch (klass_id) {
1781   // Signature-polymorphic methods: MethodHandle.invoke*, InvokeDynamic.*., VarHandle
1782   case VM_SYMBOL_ENUM_NAME(java_lang_invoke_MethodHandle):
1783   case VM_SYMBOL_ENUM_NAME(java_lang_invoke_VarHandle):
1784     if (!is_native())  break;
1785     id = MethodHandles::signature_polymorphic_name_id(method_holder(), name());
1786     if (is_static() != MethodHandles::is_signature_polymorphic_static(id))
1787       id = vmIntrinsics::_none;
1788     break;
1789 
1790   default:
1791     break;
1792   }
1793 
1794   if (id != vmIntrinsics::_none) {
1795     // Set up its iid.  It is an alias method.
1796     set_intrinsic_id(id);
1797     return;
1798   }
1799 }
1800 
1801 bool Method::load_signature_classes(const methodHandle& m, TRAPS) {
1802   if (!THREAD->can_call_java()) {
1803     // There is nothing useful this routine can do from within the Compile thread.
1804     // Hopefully, the signature contains only well-known classes.
1805     // We could scan for this and return true/false, but the caller won't care.
1806     return false;
1807   }
1808   bool sig_is_loaded = true;
1809   ResourceMark rm(THREAD);
1810   for (ResolvingSignatureStream ss(m()); !ss.is_done(); ss.next()) {
1811     if (ss.is_reference()) {
1812       // load everything, including arrays "[Lfoo;"
1813       Klass* klass = ss.as_klass(SignatureStream::ReturnNull, THREAD);
1814       // We are loading classes eagerly. If a ClassNotFoundException or
1815       // a LinkageError was generated, be sure to ignore it.
1816       if (HAS_PENDING_EXCEPTION) {
1817         if (PENDING_EXCEPTION->is_a(vmClasses::ClassNotFoundException_klass()) ||
1818             PENDING_EXCEPTION->is_a(vmClasses::LinkageError_klass())) {
1819           CLEAR_PENDING_EXCEPTION;
1820         } else {
1821           return false;
1822         }
1823       }
1824       if( klass == nullptr) { sig_is_loaded = false; }
1825     }
1826   }
1827   return sig_is_loaded;
1828 }
1829 
1830 // Exposed so field engineers can debug VM
1831 void Method::print_short_name(outputStream* st) const {
1832   ResourceMark rm;
1833 #ifdef PRODUCT
1834   st->print(" %s::", method_holder()->external_name());
1835 #else
1836   st->print(" %s::", method_holder()->internal_name());
1837 #endif
1838   name()->print_symbol_on(st);
1839   if (WizardMode) signature()->print_symbol_on(st);
1840   else if (MethodHandles::is_signature_polymorphic(intrinsic_id()))
1841     MethodHandles::print_as_basic_type_signature_on(st, signature());
1842 }
1843 
1844 // Comparer for sorting an object array containing
1845 // Method*s.
1846 static int method_comparator(Method* a, Method* b) {
1847   return a->name()->fast_compare(b->name());
1848 }
1849 
1850 // This is only done during class loading, so it is OK to assume method_idnum matches the methods() array
1851 // default_methods also uses this without the ordering for fast find_method
1852 void Method::sort_methods(Array<Method*>* methods, bool set_idnums, method_comparator_func func) {
1853   int length = methods->length();
1854   if (length > 1) {
1855     if (func == nullptr) {
1856       func = method_comparator;
1857     }
1858     {
1859       NoSafepointVerifier nsv;
1860       QuickSort::sort(methods->data(), length, func);
1861     }
1862     // Reset method ordering
1863     if (set_idnums) {
1864       for (u2 i = 0; i < length; i++) {
1865         Method* m = methods->at(i);
1866         m->set_method_idnum(i);
1867         m->set_orig_method_idnum(i);
1868       }
1869     }
1870   }
1871 }
1872 
1873 //-----------------------------------------------------------------------------------
1874 // Non-product code unless JVM/TI needs it
1875 
1876 #if !defined(PRODUCT) || INCLUDE_JVMTI
1877 class SignatureTypePrinter : public SignatureTypeNames {
1878  private:
1879   outputStream* _st;
1880   bool _use_separator;
1881 
1882   void type_name(const char* name) {
1883     if (_use_separator) _st->print(", ");
1884     _st->print("%s", name);
1885     _use_separator = true;
1886   }
1887 
1888  public:
1889   SignatureTypePrinter(Symbol* signature, outputStream* st) : SignatureTypeNames(signature) {
1890     _st = st;
1891     _use_separator = false;
1892   }
1893 
1894   void print_parameters()              { _use_separator = false; do_parameters_on(this); }
1895   void print_returntype()              { _use_separator = false; do_type(return_type()); }
1896 };
1897 
1898 
1899 void Method::print_name(outputStream* st) const {
1900   Thread *thread = Thread::current();
1901   ResourceMark rm(thread);
1902   st->print("%s ", is_static() ? "static" : "virtual");
1903   if (WizardMode) {
1904     st->print("%s.", method_holder()->internal_name());
1905     name()->print_symbol_on(st);
1906     signature()->print_symbol_on(st);
1907   } else {
1908     SignatureTypePrinter sig(signature(), st);
1909     sig.print_returntype();
1910     st->print(" %s.", method_holder()->internal_name());
1911     name()->print_symbol_on(st);
1912     st->print("(");
1913     sig.print_parameters();
1914     st->print(")");
1915   }
1916 }
1917 #endif // !PRODUCT || INCLUDE_JVMTI
1918 
1919 
1920 void Method::print_codes_on(outputStream* st, int flags) const {
1921   print_codes_on(0, code_size(), st, flags);
1922 }
1923 
1924 void Method::print_codes_on(int from, int to, outputStream* st, int flags) const {
1925   Thread *thread = Thread::current();
1926   ResourceMark rm(thread);
1927   methodHandle mh (thread, (Method*)this);
1928   BytecodeTracer::print_method_codes(mh, from, to, st, flags);
1929 }
1930 
1931 CompressedLineNumberReadStream::CompressedLineNumberReadStream(u_char* buffer) : CompressedReadStream(buffer) {
1932   _bci = 0;
1933   _line = 0;
1934 };
1935 
1936 bool CompressedLineNumberReadStream::read_pair() {
1937   jubyte next = read_byte();
1938   // Check for terminator
1939   if (next == 0) return false;
1940   if (next == 0xFF) {
1941     // Escape character, regular compression used
1942     _bci  += read_signed_int();
1943     _line += read_signed_int();
1944   } else {
1945     // Single byte compression used
1946     _bci  += next >> 3;
1947     _line += next & 0x7;
1948   }
1949   return true;
1950 }
1951 
1952 #if INCLUDE_JVMTI
1953 
1954 Bytecodes::Code Method::orig_bytecode_at(int bci) const {
1955   BreakpointInfo* bp = method_holder()->breakpoints();
1956   for (; bp != nullptr; bp = bp->next()) {
1957     if (bp->match(this, bci)) {
1958       return bp->orig_bytecode();
1959     }
1960   }
1961   {
1962     ResourceMark rm;
1963     fatal("no original bytecode found in %s at bci %d", name_and_sig_as_C_string(), bci);
1964   }
1965   return Bytecodes::_shouldnotreachhere;
1966 }
1967 
1968 void Method::set_orig_bytecode_at(int bci, Bytecodes::Code code) {
1969   assert(code != Bytecodes::_breakpoint, "cannot patch breakpoints this way");
1970   BreakpointInfo* bp = method_holder()->breakpoints();
1971   for (; bp != nullptr; bp = bp->next()) {
1972     if (bp->match(this, bci)) {
1973       bp->set_orig_bytecode(code);
1974       // and continue, in case there is more than one
1975     }
1976   }
1977 }
1978 
1979 void Method::set_breakpoint(int bci) {
1980   InstanceKlass* ik = method_holder();
1981   BreakpointInfo *bp = new BreakpointInfo(this, bci);
1982   bp->set_next(ik->breakpoints());
1983   ik->set_breakpoints(bp);
1984   // do this last:
1985   bp->set(this);
1986 }
1987 
1988 static void clear_matches(Method* m, int bci) {
1989   InstanceKlass* ik = m->method_holder();
1990   BreakpointInfo* prev_bp = nullptr;
1991   BreakpointInfo* next_bp;
1992   for (BreakpointInfo* bp = ik->breakpoints(); bp != nullptr; bp = next_bp) {
1993     next_bp = bp->next();
1994     // bci value of -1 is used to delete all breakpoints in method m (ex: clear_all_breakpoint).
1995     if (bci >= 0 ? bp->match(m, bci) : bp->match(m)) {
1996       // do this first:
1997       bp->clear(m);
1998       // unhook it
1999       if (prev_bp != nullptr)
2000         prev_bp->set_next(next_bp);
2001       else
2002         ik->set_breakpoints(next_bp);
2003       delete bp;
2004       // When class is redefined JVMTI sets breakpoint in all versions of EMCP methods
2005       // at same location. So we have multiple matching (method_index and bci)
2006       // BreakpointInfo nodes in BreakpointInfo list. We should just delete one
2007       // breakpoint for clear_breakpoint request and keep all other method versions
2008       // BreakpointInfo for future clear_breakpoint request.
2009       // bcivalue of -1 is used to clear all breakpoints (see clear_all_breakpoints)
2010       // which is being called when class is unloaded. We delete all the Breakpoint
2011       // information for all versions of method. We may not correctly restore the original
2012       // bytecode in all method versions, but that is ok. Because the class is being unloaded
2013       // so these methods won't be used anymore.
2014       if (bci >= 0) {
2015         break;
2016       }
2017     } else {
2018       // This one is a keeper.
2019       prev_bp = bp;
2020     }
2021   }
2022 }
2023 
2024 void Method::clear_breakpoint(int bci) {
2025   assert(bci >= 0, "");
2026   clear_matches(this, bci);
2027 }
2028 
2029 void Method::clear_all_breakpoints() {
2030   clear_matches(this, -1);
2031 }
2032 
2033 #endif // INCLUDE_JVMTI
2034 
2035 int Method::invocation_count() const {
2036   MethodCounters* mcs = method_counters();
2037   MethodData* mdo = method_data();
2038   if (((mcs != nullptr) ? mcs->invocation_counter()->carry() : false) ||
2039       ((mdo != nullptr) ? mdo->invocation_counter()->carry() : false)) {
2040     return InvocationCounter::count_limit;
2041   } else {
2042     return ((mcs != nullptr) ? mcs->invocation_counter()->count() : 0) +
2043            ((mdo != nullptr) ? mdo->invocation_counter()->count() : 0);
2044   }
2045 }
2046 
2047 int Method::backedge_count() const {
2048   MethodCounters* mcs = method_counters();
2049   MethodData* mdo = method_data();
2050   if (((mcs != nullptr) ? mcs->backedge_counter()->carry() : false) ||
2051       ((mdo != nullptr) ? mdo->backedge_counter()->carry() : false)) {
2052     return InvocationCounter::count_limit;
2053   } else {
2054     return ((mcs != nullptr) ? mcs->backedge_counter()->count() : 0) +
2055            ((mdo != nullptr) ? mdo->backedge_counter()->count() : 0);
2056   }
2057 }
2058 
2059 int Method::highest_comp_level() const {
2060   const MethodCounters* mcs = method_counters();
2061   nmethod* nm = code();
2062   int level = (nm != nullptr) ? nm->comp_level() : CompLevel_none;
2063   if (mcs != nullptr) {
2064     return MAX2(mcs->highest_comp_level(), level);
2065   } else {
2066     return CompLevel_none;
2067   }
2068 }
2069 
2070 int Method::highest_osr_comp_level() const {
2071   const MethodCounters* mcs = method_counters();
2072   if (mcs != nullptr) {
2073     return mcs->highest_osr_comp_level();
2074   } else {
2075     return CompLevel_none;
2076   }
2077 }
2078 
2079 void Method::set_highest_comp_level(int level) {
2080   MethodCounters* mcs = method_counters();
2081   if (mcs != nullptr) {
2082     mcs->set_highest_comp_level(level);
2083   }
2084 }
2085 
2086 void Method::set_highest_osr_comp_level(int level) {
2087   MethodCounters* mcs = method_counters();
2088   if (mcs != nullptr) {
2089     mcs->set_highest_osr_comp_level(level);
2090   }
2091 }
2092 
2093 #if INCLUDE_JVMTI
2094 
2095 BreakpointInfo::BreakpointInfo(Method* m, int bci) {
2096   _bci = bci;
2097   _name_index = m->name_index();
2098   _signature_index = m->signature_index();
2099   _orig_bytecode = (Bytecodes::Code) *m->bcp_from(_bci);
2100   if (_orig_bytecode == Bytecodes::_breakpoint)
2101     _orig_bytecode = m->orig_bytecode_at(_bci);
2102   _next = nullptr;
2103 }
2104 
2105 void BreakpointInfo::set(Method* method) {
2106 #ifdef ASSERT
2107   {
2108     Bytecodes::Code code = (Bytecodes::Code) *method->bcp_from(_bci);
2109     if (code == Bytecodes::_breakpoint)
2110       code = method->orig_bytecode_at(_bci);
2111     assert(orig_bytecode() == code, "original bytecode must be the same");
2112   }
2113 #endif
2114   Thread *thread = Thread::current();
2115   *method->bcp_from(_bci) = Bytecodes::_breakpoint;
2116   method->incr_number_of_breakpoints(thread);
2117   {
2118     // Deoptimize all dependents on this method
2119     HandleMark hm(thread);
2120     methodHandle mh(thread, method);
2121     CodeCache::mark_dependents_on_method_for_breakpoint(mh);
2122   }
2123 }
2124 
2125 void BreakpointInfo::clear(Method* method) {
2126   *method->bcp_from(_bci) = orig_bytecode();
2127   assert(method->number_of_breakpoints() > 0, "must not go negative");
2128   method->decr_number_of_breakpoints(Thread::current());
2129 }
2130 
2131 #endif // INCLUDE_JVMTI
2132 
2133 // jmethodID handling
2134 
2135 // This is a block allocating object, sort of like JNIHandleBlock, only a
2136 // lot simpler.
2137 // It's allocated on the CHeap because once we allocate a jmethodID, we can
2138 // never get rid of it.
2139 
2140 static const int min_block_size = 8;
2141 
2142 class JNIMethodBlockNode : public CHeapObj<mtClass> {
2143   friend class JNIMethodBlock;
2144   Method**        _methods;
2145   int             _number_of_methods;
2146   int             _top;
2147   JNIMethodBlockNode* _next;
2148 
2149  public:
2150 
2151   JNIMethodBlockNode(int num_methods = min_block_size);
2152 
2153   ~JNIMethodBlockNode() { FREE_C_HEAP_ARRAY(Method*, _methods); }
2154 
2155   void ensure_methods(int num_addl_methods) {
2156     if (_top < _number_of_methods) {
2157       num_addl_methods -= _number_of_methods - _top;
2158       if (num_addl_methods <= 0) {
2159         return;
2160       }
2161     }
2162     if (_next == nullptr) {
2163       _next = new JNIMethodBlockNode(MAX2(num_addl_methods, min_block_size));
2164     } else {
2165       _next->ensure_methods(num_addl_methods);
2166     }
2167   }
2168 };
2169 
2170 class JNIMethodBlock : public CHeapObj<mtClass> {
2171   JNIMethodBlockNode _head;
2172   JNIMethodBlockNode *_last_free;
2173  public:
2174   static Method* const _free_method;
2175 
2176   JNIMethodBlock(int initial_capacity = min_block_size)
2177       : _head(initial_capacity), _last_free(&_head) {}
2178 
2179   void ensure_methods(int num_addl_methods) {
2180     _last_free->ensure_methods(num_addl_methods);
2181   }
2182 
2183   Method** add_method(Method* m) {
2184     for (JNIMethodBlockNode* b = _last_free; b != nullptr; b = b->_next) {
2185       if (b->_top < b->_number_of_methods) {
2186         // top points to the next free entry.
2187         int i = b->_top;
2188         b->_methods[i] = m;
2189         b->_top++;
2190         _last_free = b;
2191         return &(b->_methods[i]);
2192       } else if (b->_top == b->_number_of_methods) {
2193         // if the next free entry ran off the block see if there's a free entry
2194         for (int i = 0; i < b->_number_of_methods; i++) {
2195           if (b->_methods[i] == _free_method) {
2196             b->_methods[i] = m;
2197             _last_free = b;
2198             return &(b->_methods[i]);
2199           }
2200         }
2201         // Only check each block once for frees.  They're very unlikely.
2202         // Increment top past the end of the block.
2203         b->_top++;
2204       }
2205       // need to allocate a next block.
2206       if (b->_next == nullptr) {
2207         b->_next = _last_free = new JNIMethodBlockNode();
2208       }
2209     }
2210     guarantee(false, "Should always allocate a free block");
2211     return nullptr;
2212   }
2213 
2214   bool contains(Method** m) {
2215     if (m == nullptr) return false;
2216     for (JNIMethodBlockNode* b = &_head; b != nullptr; b = b->_next) {
2217       if (b->_methods <= m && m < b->_methods + b->_number_of_methods) {
2218         // This is a bit of extra checking, for two reasons.  One is
2219         // that contains() deals with pointers that are passed in by
2220         // JNI code, so making sure that the pointer is aligned
2221         // correctly is valuable.  The other is that <= and > are
2222         // technically not defined on pointers, so the if guard can
2223         // pass spuriously; no modern compiler is likely to make that
2224         // a problem, though (and if one did, the guard could also
2225         // fail spuriously, which would be bad).
2226         ptrdiff_t idx = m - b->_methods;
2227         if (b->_methods + idx == m) {
2228           return true;
2229         }
2230       }
2231     }
2232     return false;  // not found
2233   }
2234 
2235   // During class unloading the methods are cleared, which is different
2236   // than freed.
2237   void clear_all_methods() {
2238     for (JNIMethodBlockNode* b = &_head; b != nullptr; b = b->_next) {
2239       for (int i = 0; i< b->_number_of_methods; i++) {
2240         b->_methods[i] = nullptr;
2241       }
2242     }
2243   }
2244 #ifndef PRODUCT
2245   int count_methods() {
2246     // count all allocated methods
2247     int count = 0;
2248     for (JNIMethodBlockNode* b = &_head; b != nullptr; b = b->_next) {
2249       for (int i = 0; i< b->_number_of_methods; i++) {
2250         if (b->_methods[i] != _free_method) count++;
2251       }
2252     }
2253     return count;
2254   }
2255 #endif // PRODUCT
2256 };
2257 
2258 // Something that can't be mistaken for an address or a markWord
2259 Method* const JNIMethodBlock::_free_method = (Method*)55;
2260 
2261 JNIMethodBlockNode::JNIMethodBlockNode(int num_methods) : _top(0), _next(nullptr) {
2262   _number_of_methods = MAX2(num_methods, min_block_size);
2263   _methods = NEW_C_HEAP_ARRAY(Method*, _number_of_methods, mtInternal);
2264   for (int i = 0; i < _number_of_methods; i++) {
2265     _methods[i] = JNIMethodBlock::_free_method;
2266   }
2267 }
2268 
2269 void Method::ensure_jmethod_ids(ClassLoaderData* cld, int capacity) {
2270   // Have to add jmethod_ids() to class loader data thread-safely.
2271   // Also have to add the method to the list safely, which the lock
2272   // protects as well.
2273   MutexLocker ml(JmethodIdCreation_lock,  Mutex::_no_safepoint_check_flag);
2274   if (cld->jmethod_ids() == nullptr) {
2275     cld->set_jmethod_ids(new JNIMethodBlock(capacity));
2276   } else {
2277     cld->jmethod_ids()->ensure_methods(capacity);
2278   }
2279 }
2280 
2281 // Add a method id to the jmethod_ids
2282 jmethodID Method::make_jmethod_id(ClassLoaderData* cld, Method* m) {
2283   // Have to add jmethod_ids() to class loader data thread-safely.
2284   // Also have to add the method to the list safely, which the lock
2285   // protects as well.
2286   assert(JmethodIdCreation_lock->owned_by_self(), "sanity check");
2287 
2288   ResourceMark rm;
2289   log_debug(jmethod)("Creating jmethodID for Method %s", m->external_name());
2290   if (cld->jmethod_ids() == nullptr) {
2291     cld->set_jmethod_ids(new JNIMethodBlock());
2292   }
2293   // jmethodID is a pointer to Method*
2294   return (jmethodID)cld->jmethod_ids()->add_method(m);
2295 }
2296 
2297 jmethodID Method::jmethod_id() {
2298   methodHandle mh(Thread::current(), this);
2299   return method_holder()->get_jmethod_id(mh);
2300 }
2301 
2302 void Method::change_method_associated_with_jmethod_id(jmethodID jmid, Method* new_method) {
2303   // Can't assert the method_holder is the same because the new method has the
2304   // scratch method holder.
2305   assert(resolve_jmethod_id(jmid)->method_holder()->class_loader()
2306            == new_method->method_holder()->class_loader() ||
2307            new_method->method_holder()->class_loader() == nullptr, // allow Unsafe substitution
2308          "changing to a different class loader");
2309   // Just change the method in place, jmethodID pointer doesn't change.
2310   *((Method**)jmid) = new_method;
2311 }
2312 
2313 bool Method::is_method_id(jmethodID mid) {
2314   Method* m = resolve_jmethod_id(mid);
2315   assert(m != nullptr, "should be called with non-null method");
2316   InstanceKlass* ik = m->method_holder();
2317   ClassLoaderData* cld = ik->class_loader_data();
2318   if (cld->jmethod_ids() == nullptr) return false;
2319   return (cld->jmethod_ids()->contains((Method**)mid));
2320 }
2321 
2322 Method* Method::checked_resolve_jmethod_id(jmethodID mid) {
2323   if (mid == nullptr) return nullptr;
2324   Method* o = resolve_jmethod_id(mid);
2325   if (o == nullptr || o == JNIMethodBlock::_free_method) {
2326     return nullptr;
2327   }
2328   // Method should otherwise be valid. Assert for testing.
2329   assert(is_valid_method(o), "should be valid jmethodid");
2330   // If the method's class holder object is unreferenced, but not yet marked as
2331   // unloaded, we need to return null here too because after a safepoint, its memory
2332   // will be reclaimed.
2333   return o->method_holder()->is_loader_alive() ? o : nullptr;
2334 };
2335 
2336 void Method::set_on_stack(const bool value) {
2337   // Set both the method itself and its constant pool.  The constant pool
2338   // on stack means some method referring to it is also on the stack.
2339   constants()->set_on_stack(value);
2340 
2341   bool already_set = on_stack_flag();
2342   set_on_stack_flag(value);
2343   if (value && !already_set) {
2344     MetadataOnStackMark::record(this);
2345   }
2346 }
2347 
2348 void Method::record_gc_epoch() {
2349   // If any method is on the stack in continuations, none of them can be reclaimed,
2350   // so save the marking cycle to check for the whole class in the cpCache.
2351   // The cpCache is writeable.
2352   constants()->cache()->record_gc_epoch();
2353 }
2354 
2355 // Called when the class loader is unloaded to make all methods weak.
2356 void Method::clear_jmethod_ids(ClassLoaderData* loader_data) {
2357   loader_data->jmethod_ids()->clear_all_methods();
2358 }
2359 
2360 void Method::clear_jmethod_id() {
2361   // Being at a safepoint prevents racing against other class redefinitions
2362   assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
2363   // The jmethodID is not stored in the Method instance, we need to look it up first
2364   jmethodID methodid = find_jmethod_id_or_null();
2365   // We need to make sure that jmethodID actually resolves to this method
2366   // - multiple redefined versions may share jmethodID slots and if a method
2367   //   has already been rewired to a newer version we could be removing reference
2368   //   to a still existing method instance
2369   if (methodid != nullptr && *((Method**)methodid) == this) {
2370     *((Method**)methodid) = nullptr;
2371   }
2372 }
2373 
2374 bool Method::has_method_vptr(const void* ptr) {
2375   Method m;
2376   // This assumes that the vtbl pointer is the first word of a C++ object.
2377   return dereference_vptr(&m) == dereference_vptr(ptr);
2378 }
2379 
2380 // Check that this pointer is valid by checking that the vtbl pointer matches
2381 bool Method::is_valid_method(const Method* m) {
2382   if (m == nullptr) {
2383     return false;
2384   } else if ((intptr_t(m) & (wordSize-1)) != 0) {
2385     // Quick sanity check on pointer.
2386     return false;
2387   } else if (!os::is_readable_range(m, m + 1)) {
2388     return false;
2389   } else if (m->is_shared()) {
2390     return CppVtables::is_valid_shared_method(m);
2391   } else if (Metaspace::contains_non_shared(m)) {
2392     return has_method_vptr((const void*)m);
2393   } else {
2394     return false;
2395   }
2396 }
2397 
2398 #ifndef PRODUCT
2399 void Method::print_jmethod_ids_count(const ClassLoaderData* loader_data, outputStream* out) {
2400   out->print("%d", loader_data->jmethod_ids()->count_methods());
2401 }
2402 #endif // PRODUCT
2403 
2404 
2405 // Printing
2406 
2407 #ifndef PRODUCT
2408 
2409 void Method::print_on(outputStream* st) const {
2410   ResourceMark rm;
2411   assert(is_method(), "must be method");
2412   st->print_cr("%s", internal_name());
2413   st->print_cr(" - this oop:          " PTR_FORMAT, p2i(this));
2414   st->print   (" - method holder:     "); method_holder()->print_value_on(st); st->cr();
2415   st->print   (" - constants:         " PTR_FORMAT " ", p2i(constants()));
2416   constants()->print_value_on(st); st->cr();
2417   st->print   (" - access:            0x%x  ", access_flags().as_method_flags()); access_flags().print_on(st); st->cr();
2418   st->print   (" - flags:             0x%x  ", _flags.as_int()); _flags.print_on(st); st->cr();
2419   st->print   (" - name:              ");    name()->print_value_on(st); st->cr();
2420   st->print   (" - signature:         ");    signature()->print_value_on(st); st->cr();
2421   st->print_cr(" - max stack:         %d",   max_stack());
2422   st->print_cr(" - max locals:        %d",   max_locals());
2423   st->print_cr(" - size of params:    %d",   size_of_parameters());
2424   st->print_cr(" - method size:       %d",   method_size());
2425   if (intrinsic_id() != vmIntrinsics::_none)
2426     st->print_cr(" - intrinsic id:      %d %s", vmIntrinsics::as_int(intrinsic_id()), vmIntrinsics::name_at(intrinsic_id()));
2427   if (highest_comp_level() != CompLevel_none)
2428     st->print_cr(" - highest level:     %d", highest_comp_level());
2429   st->print_cr(" - vtable index:      %d",   _vtable_index);
2430   st->print_cr(" - i2i entry:         " PTR_FORMAT, p2i(interpreter_entry()));
2431   st->print(   " - adapters:          ");
2432   AdapterHandlerEntry* a = ((Method*)this)->adapter();
2433   if (a == nullptr)
2434     st->print_cr(PTR_FORMAT, p2i(a));
2435   else
2436     a->print_adapter_on(st);
2437   st->print_cr(" - compiled entry     " PTR_FORMAT, p2i(from_compiled_entry()));
2438   st->print_cr(" - code size:         %d",   code_size());
2439   if (code_size() != 0) {
2440     st->print_cr(" - code start:        " PTR_FORMAT, p2i(code_base()));
2441     st->print_cr(" - code end (excl):   " PTR_FORMAT, p2i(code_base() + code_size()));
2442   }
2443   if (method_data() != nullptr) {
2444     st->print_cr(" - method data:       " PTR_FORMAT, p2i(method_data()));
2445   }
2446   st->print_cr(" - checked ex length: %d",   checked_exceptions_length());
2447   if (checked_exceptions_length() > 0) {
2448     CheckedExceptionElement* table = checked_exceptions_start();
2449     st->print_cr(" - checked ex start:  " PTR_FORMAT, p2i(table));
2450     if (Verbose) {
2451       for (int i = 0; i < checked_exceptions_length(); i++) {
2452         st->print_cr("   - throws %s", constants()->printable_name_at(table[i].class_cp_index));
2453       }
2454     }
2455   }
2456   if (has_linenumber_table()) {
2457     u_char* table = compressed_linenumber_table();
2458     st->print_cr(" - linenumber start:  " PTR_FORMAT, p2i(table));
2459     if (Verbose) {
2460       CompressedLineNumberReadStream stream(table);
2461       while (stream.read_pair()) {
2462         st->print_cr("   - line %d: %d", stream.line(), stream.bci());
2463       }
2464     }
2465   }
2466   st->print_cr(" - localvar length:   %d",   localvariable_table_length());
2467   if (localvariable_table_length() > 0) {
2468     LocalVariableTableElement* table = localvariable_table_start();
2469     st->print_cr(" - localvar start:    " PTR_FORMAT, p2i(table));
2470     if (Verbose) {
2471       for (int i = 0; i < localvariable_table_length(); i++) {
2472         int bci = table[i].start_bci;
2473         int len = table[i].length;
2474         const char* name = constants()->printable_name_at(table[i].name_cp_index);
2475         const char* desc = constants()->printable_name_at(table[i].descriptor_cp_index);
2476         int slot = table[i].slot;
2477         st->print_cr("   - %s %s bci=%d len=%d slot=%d", desc, name, bci, len, slot);
2478       }
2479     }
2480   }
2481   if (code() != nullptr) {
2482     st->print   (" - compiled code: ");
2483     code()->print_value_on(st);
2484   }
2485   if (is_native()) {
2486     st->print_cr(" - native function:   " PTR_FORMAT, p2i(native_function()));
2487     st->print_cr(" - signature handler: " PTR_FORMAT, p2i(signature_handler()));
2488   }
2489 }
2490 
2491 void Method::print_linkage_flags(outputStream* st) {
2492   access_flags().print_on(st);
2493   if (is_default_method()) {
2494     st->print("default ");
2495   }
2496   if (is_overpass()) {
2497     st->print("overpass ");
2498   }
2499 }
2500 #endif //PRODUCT
2501 
2502 void Method::print_value_on(outputStream* st) const {
2503   assert(is_method(), "must be method");
2504   st->print("%s", internal_name());
2505   print_address_on(st);
2506   st->print(" ");
2507   name()->print_value_on(st);
2508   st->print(" ");
2509   signature()->print_value_on(st);
2510   st->print(" in ");
2511   method_holder()->print_value_on(st);
2512   if (WizardMode) st->print("#%d", _vtable_index);
2513   if (WizardMode) st->print("[%d,%d]", size_of_parameters(), max_locals());
2514   if (WizardMode && code() != nullptr) st->print(" ((nmethod*)%p)", code());
2515 }
2516 
2517 // Verification
2518 
2519 void Method::verify_on(outputStream* st) {
2520   guarantee(is_method(), "object must be method");
2521   guarantee(constants()->is_constantPool(), "should be constant pool");
2522   MethodData* md = method_data();
2523   guarantee(md == nullptr ||
2524       md->is_methodData(), "should be method data");
2525 }