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 "classfile/javaClasses.inline.hpp"
  26 #include "classfile/symbolTable.hpp"
  27 #include "classfile/vmClasses.hpp"
  28 #include "classfile/vmSymbols.hpp"
  29 #include "code/codeCache.hpp"
  30 #include "compiler/compilationPolicy.hpp"
  31 #include "compiler/compileBroker.hpp"
  32 #include "compiler/disassembler.hpp"
  33 #include "gc/shared/barrierSetNMethod.hpp"
  34 #include "gc/shared/collectedHeap.hpp"
  35 #include "interpreter/bytecodeTracer.hpp"
  36 #include "interpreter/interpreter.hpp"
  37 #include "interpreter/interpreterRuntime.hpp"
  38 #include "interpreter/linkResolver.hpp"
  39 #include "interpreter/templateTable.hpp"
  40 #include "jvm_io.h"
  41 #include "logging/log.hpp"
  42 #include "memory/oopFactory.hpp"
  43 #include "memory/resourceArea.hpp"
  44 #include "memory/universe.hpp"
  45 #include "oops/constantPool.inline.hpp"
  46 #include "oops/cpCache.inline.hpp"
  47 #include "oops/instanceKlass.inline.hpp"
  48 #include "oops/klass.inline.hpp"
  49 #include "oops/methodData.hpp"
  50 #include "oops/method.inline.hpp"
  51 #include "oops/objArrayKlass.hpp"
  52 #include "oops/objArrayOop.inline.hpp"
  53 #include "oops/oop.inline.hpp"
  54 #include "oops/symbol.hpp"
  55 #include "prims/jvmtiExport.hpp"
  56 #include "prims/methodHandles.hpp"
  57 #include "prims/nativeLookup.hpp"
  58 #include "runtime/atomic.hpp"
  59 #include "runtime/continuation.hpp"
  60 #include "runtime/deoptimization.hpp"
  61 #include "runtime/fieldDescriptor.inline.hpp"
  62 #include "runtime/frame.inline.hpp"
  63 #include "runtime/handles.inline.hpp"
  64 #include "runtime/icache.hpp"
  65 #include "runtime/interfaceSupport.inline.hpp"
  66 #include "runtime/java.hpp"
  67 #include "runtime/javaCalls.hpp"
  68 #include "runtime/jfieldIDWorkaround.hpp"
  69 #include "runtime/osThread.hpp"
  70 #include "runtime/sharedRuntime.hpp"
  71 #include "runtime/stackWatermarkSet.hpp"
  72 #include "runtime/stubRoutines.hpp"
  73 #include "runtime/synchronizer.inline.hpp"
  74 #include "utilities/align.hpp"
  75 #include "utilities/checkedCast.hpp"
  76 #include "utilities/copy.hpp"
  77 #include "utilities/events.hpp"
  78 
  79 // Helper class to access current interpreter state
  80 class LastFrameAccessor : public StackObj {
  81   frame _last_frame;
  82 public:
  83   LastFrameAccessor(JavaThread* current) {
  84     assert(current == Thread::current(), "sanity");
  85     _last_frame = current->last_frame();
  86   }
  87   bool is_interpreted_frame() const              { return _last_frame.is_interpreted_frame(); }
  88   Method*   method() const                       { return _last_frame.interpreter_frame_method(); }
  89   address   bcp() const                          { return _last_frame.interpreter_frame_bcp(); }
  90   int       bci() const                          { return _last_frame.interpreter_frame_bci(); }
  91   address   mdp() const                          { return _last_frame.interpreter_frame_mdp(); }
  92 
  93   void      set_bcp(address bcp)                 { _last_frame.interpreter_frame_set_bcp(bcp); }
  94   void      set_mdp(address dp)                  { _last_frame.interpreter_frame_set_mdp(dp); }
  95 
  96   // pass method to avoid calling unsafe bcp_to_method (partial fix 4926272)
  97   Bytecodes::Code code() const                   { return Bytecodes::code_at(method(), bcp()); }
  98 
  99   Bytecode  bytecode() const                     { return Bytecode(method(), bcp()); }
 100   int get_index_u1(Bytecodes::Code bc) const     { return bytecode().get_index_u1(bc); }
 101   int get_index_u2(Bytecodes::Code bc) const     { return bytecode().get_index_u2(bc); }
 102   int get_index_u4(Bytecodes::Code bc) const     { return bytecode().get_index_u4(bc); }
 103   int number_of_dimensions() const               { return bcp()[3]; }
 104 
 105   oop callee_receiver(Symbol* signature) {
 106     return _last_frame.interpreter_callee_receiver(signature);
 107   }
 108   BasicObjectLock* monitor_begin() const {
 109     return _last_frame.interpreter_frame_monitor_begin();
 110   }
 111   BasicObjectLock* monitor_end() const {
 112     return _last_frame.interpreter_frame_monitor_end();
 113   }
 114   BasicObjectLock* next_monitor(BasicObjectLock* current) const {
 115     return _last_frame.next_monitor_in_interpreter_frame(current);
 116   }
 117 
 118   frame& get_frame()                             { return _last_frame; }
 119 };
 120 
 121 class ProfileTrapsMark : public StackObj {
 122   JavaThread* _thread;
 123  public:
 124   ProfileTrapsMark(JavaThread* current) : _thread(current) {}
 125   ~ProfileTrapsMark() {
 126     JavaThread* THREAD = _thread;
 127     if (HAS_PENDING_EXCEPTION) {
 128       if (ProfileTraps && PENDING_EXCEPTION->klass()->name() == vmSymbols::java_lang_NullPointerException()) {
 129         // Preserve the original exception across the call to note_trap()
 130         PreserveExceptionMark pm(_thread);
 131         // Recording the trap will help the compiler to potentially recognize this exception as "hot"
 132         InterpreterRuntime::note_trap(_thread, Deoptimization::Reason_null_check);
 133       }
 134     }
 135   }
 136 };
 137 
 138 //------------------------------------------------------------------------------------------------------------------------
 139 // State accessors
 140 
 141 void InterpreterRuntime::set_bcp_and_mdp(address bcp, JavaThread* current) {
 142   LastFrameAccessor last_frame(current);
 143   last_frame.set_bcp(bcp);
 144   if (ProfileInterpreter) {
 145     // ProfileTraps uses MDOs independently of ProfileInterpreter.
 146     // That is why we must check both ProfileInterpreter and mdo != nullptr.
 147     MethodData* mdo = last_frame.method()->method_data();
 148     if (mdo != nullptr) {
 149       NEEDS_CLEANUP;
 150       last_frame.set_mdp(mdo->bci_to_dp(last_frame.bci()));
 151     }
 152   }
 153 }
 154 
 155 //------------------------------------------------------------------------------------------------------------------------
 156 // Constants
 157 
 158 
 159 JRT_ENTRY(void, InterpreterRuntime::ldc(JavaThread* current, bool wide))
 160   // access constant pool
 161   LastFrameAccessor last_frame(current);
 162   ConstantPool* pool = last_frame.method()->constants();
 163   int cp_index = wide ? last_frame.get_index_u2(Bytecodes::_ldc_w) : last_frame.get_index_u1(Bytecodes::_ldc);
 164   constantTag tag = pool->tag_at(cp_index);
 165 
 166   assert (tag.is_unresolved_klass() || tag.is_klass(), "wrong ldc call");
 167   Klass* klass = pool->klass_at(cp_index, CHECK);
 168   oop java_class = klass->java_mirror();
 169   current->set_vm_result_oop(java_class);
 170 JRT_END
 171 
 172 JRT_ENTRY(void, InterpreterRuntime::resolve_ldc(JavaThread* current, Bytecodes::Code bytecode)) {
 173   assert(bytecode == Bytecodes::_ldc ||
 174          bytecode == Bytecodes::_ldc_w ||
 175          bytecode == Bytecodes::_ldc2_w ||
 176          bytecode == Bytecodes::_fast_aldc ||
 177          bytecode == Bytecodes::_fast_aldc_w, "wrong bc");
 178   ResourceMark rm(current);
 179   const bool is_fast_aldc = (bytecode == Bytecodes::_fast_aldc ||
 180                              bytecode == Bytecodes::_fast_aldc_w);
 181   LastFrameAccessor last_frame(current);
 182   methodHandle m (current, last_frame.method());
 183   Bytecode_loadconstant ldc(m, last_frame.bci());
 184 
 185   // Double-check the size.  (Condy can have any type.)
 186   BasicType type = ldc.result_type();
 187   switch (type2size[type]) {
 188   case 2: guarantee(bytecode == Bytecodes::_ldc2_w, ""); break;
 189   case 1: guarantee(bytecode != Bytecodes::_ldc2_w, ""); break;
 190   default: ShouldNotReachHere();
 191   }
 192 
 193   // Resolve the constant.  This does not do unboxing.
 194   // But it does replace Universe::the_null_sentinel by null.
 195   oop result = ldc.resolve_constant(CHECK);
 196   assert(result != nullptr || is_fast_aldc, "null result only valid for fast_aldc");
 197 
 198 #ifdef ASSERT
 199   {
 200     // The bytecode wrappers aren't GC-safe so construct a new one
 201     Bytecode_loadconstant ldc2(m, last_frame.bci());
 202     int rindex = ldc2.cache_index();
 203     if (rindex < 0)
 204       rindex = m->constants()->cp_to_object_index(ldc2.pool_index());
 205     if (rindex >= 0) {
 206       oop coop = m->constants()->resolved_reference_at(rindex);
 207       oop roop = (result == nullptr ? Universe::the_null_sentinel() : result);
 208       assert(roop == coop, "expected result for assembly code");
 209     }
 210   }
 211 #endif
 212   current->set_vm_result_oop(result);
 213   if (!is_fast_aldc) {
 214     // Tell the interpreter how to unbox the primitive.
 215     guarantee(java_lang_boxing_object::is_instance(result, type), "");
 216     int offset = java_lang_boxing_object::value_offset(type);
 217     intptr_t flags = ((as_TosState(type) << ConstantPoolCache::tos_state_shift)
 218                       | (offset & ConstantPoolCache::field_index_mask));
 219     current->set_vm_result_metadata((Metadata*)flags);
 220   }
 221 }
 222 JRT_END
 223 
 224 
 225 //------------------------------------------------------------------------------------------------------------------------
 226 // Allocation
 227 
 228 JRT_ENTRY(void, InterpreterRuntime::_new(JavaThread* current, ConstantPool* pool, int index))
 229   Klass* k = pool->klass_at(index, CHECK);
 230   InstanceKlass* klass = InstanceKlass::cast(k);
 231 
 232   // Make sure we are not instantiating an abstract klass
 233   klass->check_valid_for_instantiation(true, CHECK);
 234 
 235   // Make sure klass is initialized
 236   klass->initialize_preemptable(CHECK_AND_CLEAR_PREEMPTED);
 237 
 238   oop obj = klass->allocate_instance(CHECK);
 239   current->set_vm_result_oop(obj);
 240 JRT_END
 241 
 242 
 243 JRT_ENTRY(void, InterpreterRuntime::newarray(JavaThread* current, BasicType type, jint size))
 244   oop obj = oopFactory::new_typeArray(type, size, CHECK);
 245   current->set_vm_result_oop(obj);
 246 JRT_END
 247 
 248 
 249 JRT_ENTRY(void, InterpreterRuntime::anewarray(JavaThread* current, ConstantPool* pool, int index, jint size))
 250   Klass*    klass = pool->klass_at(index, CHECK);
 251   objArrayOop obj = oopFactory::new_objArray(klass, size, CHECK);
 252   current->set_vm_result_oop(obj);
 253 JRT_END
 254 
 255 
 256 JRT_ENTRY(void, InterpreterRuntime::multianewarray(JavaThread* current, jint* first_size_address))
 257   // We may want to pass in more arguments - could make this slightly faster
 258   LastFrameAccessor last_frame(current);
 259   ConstantPool* constants = last_frame.method()->constants();
 260   int          i = last_frame.get_index_u2(Bytecodes::_multianewarray);
 261   Klass* klass   = constants->klass_at(i, CHECK);
 262   int   nof_dims = last_frame.number_of_dimensions();
 263   assert(klass->is_klass(), "not a class");
 264   assert(nof_dims >= 1, "multianewarray rank must be nonzero");
 265 
 266   // We must create an array of jints to pass to multi_allocate.
 267   ResourceMark rm(current);
 268   const int small_dims = 10;
 269   jint dim_array[small_dims];
 270   jint *dims = &dim_array[0];
 271   if (nof_dims > small_dims) {
 272     dims = (jint*) NEW_RESOURCE_ARRAY(jint, nof_dims);
 273   }
 274   for (int index = 0; index < nof_dims; index++) {
 275     // offset from first_size_address is addressed as local[index]
 276     int n = Interpreter::local_offset_in_bytes(index)/jintSize;
 277     dims[index] = first_size_address[n];
 278   }
 279   oop obj = ArrayKlass::cast(klass)->multi_allocate(nof_dims, dims, CHECK);
 280   current->set_vm_result_oop(obj);
 281 JRT_END
 282 
 283 
 284 JRT_ENTRY(void, InterpreterRuntime::register_finalizer(JavaThread* current, oopDesc* obj))
 285   assert(oopDesc::is_oop(obj), "must be a valid oop");
 286   assert(obj->klass()->has_finalizer(), "shouldn't be here otherwise");
 287   InstanceKlass::register_finalizer(instanceOop(obj), CHECK);
 288 JRT_END
 289 
 290 
 291 // Quicken instance-of and check-cast bytecodes
 292 JRT_ENTRY(void, InterpreterRuntime::quicken_io_cc(JavaThread* current))
 293   // Force resolving; quicken the bytecode
 294   LastFrameAccessor last_frame(current);
 295   int which = last_frame.get_index_u2(Bytecodes::_checkcast);
 296   ConstantPool* cpool = last_frame.method()->constants();
 297   // We'd expect to assert that we're only here to quicken bytecodes, but in a multithreaded
 298   // program we might have seen an unquick'd bytecode in the interpreter but have another
 299   // thread quicken the bytecode before we get here.
 300   // assert( cpool->tag_at(which).is_unresolved_klass(), "should only come here to quicken bytecodes" );
 301   Klass* klass = cpool->klass_at(which, CHECK);
 302   current->set_vm_result_metadata(klass);
 303 JRT_END
 304 
 305 
 306 //------------------------------------------------------------------------------------------------------------------------
 307 // Exceptions
 308 
 309 void InterpreterRuntime::note_trap_inner(JavaThread* current, int reason,
 310                                          const methodHandle& trap_method, int trap_bci) {
 311   if (trap_method.not_null()) {
 312     MethodData* trap_mdo = trap_method->method_data();
 313     if (trap_mdo == nullptr) {
 314       ExceptionMark em(current);
 315       JavaThread* THREAD = current; // For exception macros.
 316       Method::build_profiling_method_data(trap_method, THREAD);
 317       if (HAS_PENDING_EXCEPTION) {
 318         // Only metaspace OOM is expected. No Java code executed.
 319         assert((PENDING_EXCEPTION->is_a(vmClasses::OutOfMemoryError_klass())),
 320                "we expect only an OOM error here");
 321         CLEAR_PENDING_EXCEPTION;
 322       }
 323       trap_mdo = trap_method->method_data();
 324       // and fall through...
 325     }
 326     if (trap_mdo != nullptr) {
 327       // Update per-method count of trap events.  The interpreter
 328       // is updating the MDO to simulate the effect of compiler traps.
 329       Deoptimization::update_method_data_from_interpreter(trap_mdo, trap_bci, reason);
 330     }
 331   }
 332 }
 333 
 334 // Assume the compiler is (or will be) interested in this event.
 335 // If necessary, create an MDO to hold the information, and record it.
 336 void InterpreterRuntime::note_trap(JavaThread* current, int reason) {
 337   assert(ProfileTraps, "call me only if profiling");
 338   LastFrameAccessor last_frame(current);
 339   methodHandle trap_method(current, last_frame.method());
 340   int trap_bci = trap_method->bci_from(last_frame.bcp());
 341   note_trap_inner(current, reason, trap_method, trap_bci);
 342 }
 343 
 344 static Handle get_preinitialized_exception(Klass* k, TRAPS) {
 345   // get klass
 346   InstanceKlass* klass = InstanceKlass::cast(k);
 347   assert(klass->is_initialized(),
 348          "this klass should have been initialized during VM initialization");
 349   // create instance - do not call constructor since we may have no
 350   // (java) stack space left (should assert constructor is empty)
 351   Handle exception;
 352   oop exception_oop = klass->allocate_instance(CHECK_(exception));
 353   exception = Handle(THREAD, exception_oop);
 354   if (StackTraceInThrowable) {
 355     java_lang_Throwable::fill_in_stack_trace(exception);
 356   }
 357   return exception;
 358 }
 359 
 360 // Special handling for stack overflow: since we don't have any (java) stack
 361 // space left we use the pre-allocated & pre-initialized StackOverflowError
 362 // klass to create an stack overflow error instance.  We do not call its
 363 // constructor for the same reason (it is empty, anyway).
 364 JRT_ENTRY(void, InterpreterRuntime::throw_StackOverflowError(JavaThread* current))
 365   Handle exception = get_preinitialized_exception(
 366                                  vmClasses::StackOverflowError_klass(),
 367                                  CHECK);
 368   // Increment counter for hs_err file reporting
 369   Atomic::inc(&Exceptions::_stack_overflow_errors);
 370   // Remove the ScopedValue bindings in case we got a StackOverflowError
 371   // while we were trying to manipulate ScopedValue bindings.
 372   current->clear_scopedValueBindings();
 373   THROW_HANDLE(exception);
 374 JRT_END
 375 
 376 JRT_ENTRY(void, InterpreterRuntime::throw_delayed_StackOverflowError(JavaThread* current))
 377   Handle exception = get_preinitialized_exception(
 378                                  vmClasses::StackOverflowError_klass(),
 379                                  CHECK);
 380   java_lang_Throwable::set_message(exception(),
 381           Universe::delayed_stack_overflow_error_message());
 382   // Increment counter for hs_err file reporting
 383   Atomic::inc(&Exceptions::_stack_overflow_errors);
 384   // Remove the ScopedValue bindings in case we got a StackOverflowError
 385   // while we were trying to manipulate ScopedValue bindings.
 386   current->clear_scopedValueBindings();
 387   THROW_HANDLE(exception);
 388 JRT_END
 389 
 390 JRT_ENTRY(void, InterpreterRuntime::create_exception(JavaThread* current, char* name, char* message))
 391   // lookup exception klass
 392   TempNewSymbol s = SymbolTable::new_symbol(name);
 393   if (ProfileTraps) {
 394     if (s == vmSymbols::java_lang_ArithmeticException()) {
 395       note_trap(current, Deoptimization::Reason_div0_check);
 396     } else if (s == vmSymbols::java_lang_NullPointerException()) {
 397       note_trap(current, Deoptimization::Reason_null_check);
 398     }
 399   }
 400   // create exception
 401   Handle exception = Exceptions::new_exception(current, s, message);
 402   current->set_vm_result_oop(exception());
 403 JRT_END
 404 
 405 
 406 JRT_ENTRY(void, InterpreterRuntime::create_klass_exception(JavaThread* current, char* name, oopDesc* obj))
 407   // Produce the error message first because note_trap can safepoint
 408   ResourceMark rm(current);
 409   const char* klass_name = obj->klass()->external_name();
 410   // lookup exception klass
 411   TempNewSymbol s = SymbolTable::new_symbol(name);
 412   if (ProfileTraps) {
 413     if (s == vmSymbols::java_lang_ArrayStoreException()) {
 414       note_trap(current, Deoptimization::Reason_array_check);
 415     } else {
 416       note_trap(current, Deoptimization::Reason_class_check);
 417     }
 418   }
 419   // create exception, with klass name as detail message
 420   Handle exception = Exceptions::new_exception(current, s, klass_name);
 421   current->set_vm_result_oop(exception());
 422 JRT_END
 423 
 424 JRT_ENTRY(void, InterpreterRuntime::throw_ArrayIndexOutOfBoundsException(JavaThread* current, arrayOopDesc* a, jint index))
 425   // Produce the error message first because note_trap can safepoint
 426   ResourceMark rm(current);
 427   stringStream ss;
 428   ss.print("Index %d out of bounds for length %d", index, a->length());
 429 
 430   if (ProfileTraps) {
 431     note_trap(current, Deoptimization::Reason_range_check);
 432   }
 433 
 434   THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
 435 JRT_END
 436 
 437 JRT_ENTRY(void, InterpreterRuntime::throw_ClassCastException(
 438   JavaThread* current, oopDesc* obj))
 439 
 440   // Produce the error message first because note_trap can safepoint
 441   ResourceMark rm(current);
 442   char* message = SharedRuntime::generate_class_cast_message(
 443     current, obj->klass());
 444 
 445   if (ProfileTraps) {
 446     note_trap(current, Deoptimization::Reason_class_check);
 447   }
 448 
 449   // create exception
 450   THROW_MSG(vmSymbols::java_lang_ClassCastException(), message);
 451 JRT_END
 452 
 453 // exception_handler_for_exception(...) returns the continuation address,
 454 // the exception oop (via TLS) and sets the bci/bcp for the continuation.
 455 // The exception oop is returned to make sure it is preserved over GC (it
 456 // is only on the stack if the exception was thrown explicitly via athrow).
 457 // During this operation, the expression stack contains the values for the
 458 // bci where the exception happened. If the exception was propagated back
 459 // from a call, the expression stack contains the values for the bci at the
 460 // invoke w/o arguments (i.e., as if one were inside the call).
 461 // Note that the implementation of this method assumes it's only called when an exception has actually occured
 462 JRT_ENTRY(address, InterpreterRuntime::exception_handler_for_exception(JavaThread* current, oopDesc* exception))
 463   // We get here after we have unwound from a callee throwing an exception
 464   // into the interpreter. Any deferred stack processing is notified of
 465   // the event via the StackWatermarkSet.
 466   StackWatermarkSet::after_unwind(current);
 467 
 468   LastFrameAccessor last_frame(current);
 469   Handle             h_exception(current, exception);
 470   methodHandle       h_method   (current, last_frame.method());
 471   constantPoolHandle h_constants(current, h_method->constants());
 472   bool               should_repeat;
 473   int                handler_bci;
 474   int                current_bci = last_frame.bci();
 475 
 476   if (current->frames_to_pop_failed_realloc() > 0) {
 477     // Allocation of scalar replaced object used in this frame
 478     // failed. Unconditionally pop the frame.
 479     current->dec_frames_to_pop_failed_realloc();
 480     current->set_vm_result_oop(h_exception());
 481     // If the method is synchronized we already unlocked the monitor
 482     // during deoptimization so the interpreter needs to skip it when
 483     // the frame is popped.
 484     current->set_do_not_unlock_if_synchronized(true);
 485     return Interpreter::remove_activation_entry();
 486   }
 487 
 488   // Need to do this check first since when _do_not_unlock_if_synchronized
 489   // is set, we don't want to trigger any classloading which may make calls
 490   // into java, or surprisingly find a matching exception handler for bci 0
 491   // since at this moment the method hasn't been "officially" entered yet.
 492   if (current->do_not_unlock_if_synchronized()) {
 493     ResourceMark rm;
 494     assert(current_bci == 0,  "bci isn't zero for do_not_unlock_if_synchronized");
 495     current->set_vm_result_oop(exception);
 496     return Interpreter::remove_activation_entry();
 497   }
 498 
 499   do {
 500     should_repeat = false;
 501 
 502     // assertions
 503     assert(h_exception.not_null(), "null exceptions should be handled by athrow");
 504     // Check that exception is a subclass of Throwable.
 505     assert(h_exception->is_a(vmClasses::Throwable_klass()),
 506            "Exception not subclass of Throwable");
 507 
 508     // tracing
 509     if (log_is_enabled(Info, exceptions)) {
 510       ResourceMark rm(current);
 511       stringStream tempst;
 512       tempst.print("interpreter method <%s>\n"
 513                    " at bci %d for thread " INTPTR_FORMAT " (%s)",
 514                    h_method->print_value_string(), current_bci, p2i(current), current->name());
 515       Exceptions::log_exception(h_exception, tempst.as_string());
 516     }
 517 // Don't go paging in something which won't be used.
 518 //     else if (extable->length() == 0) {
 519 //       // disabled for now - interpreter is not using shortcut yet
 520 //       // (shortcut is not to call runtime if we have no exception handlers)
 521 //       // warning("performance bug: should not call runtime if method has no exception handlers");
 522 //     }
 523     // for AbortVMOnException flag
 524     Exceptions::debug_check_abort(h_exception);
 525 
 526     // exception handler lookup
 527     Klass* klass = h_exception->klass();
 528     handler_bci = Method::fast_exception_handler_bci_for(h_method, klass, current_bci, THREAD);
 529     if (HAS_PENDING_EXCEPTION) {
 530       // We threw an exception while trying to find the exception handler.
 531       // Transfer the new exception to the exception handle which will
 532       // be set into thread local storage, and do another lookup for an
 533       // exception handler for this exception, this time starting at the
 534       // BCI of the exception handler which caused the exception to be
 535       // thrown (bug 4307310).
 536       h_exception = Handle(THREAD, PENDING_EXCEPTION);
 537       CLEAR_PENDING_EXCEPTION;
 538       if (handler_bci >= 0) {
 539         current_bci = handler_bci;
 540         should_repeat = true;
 541       }
 542     }
 543   } while (should_repeat == true);
 544 
 545 #if INCLUDE_JVMCI
 546   if (EnableJVMCI && h_method->method_data() != nullptr) {
 547     ResourceMark rm(current);
 548     MethodData* mdo = h_method->method_data();
 549 
 550     // Lock to read ProfileData, and ensure lock is not broken by a safepoint
 551     MutexLocker ml(mdo->extra_data_lock(), Mutex::_no_safepoint_check_flag);
 552 
 553     ProfileData* pdata = mdo->allocate_bci_to_data(current_bci, nullptr);
 554     if (pdata != nullptr && pdata->is_BitData()) {
 555       BitData* bit_data = (BitData*) pdata;
 556       bit_data->set_exception_seen();
 557     }
 558   }
 559 #endif
 560 
 561   // notify JVMTI of an exception throw; JVMTI will detect if this is a first
 562   // time throw or a stack unwinding throw and accordingly notify the debugger
 563   if (JvmtiExport::can_post_on_exceptions()) {
 564     JvmtiExport::post_exception_throw(current, h_method(), last_frame.bcp(), h_exception());
 565   }
 566 
 567   address continuation = nullptr;
 568   address handler_pc = nullptr;
 569   if (handler_bci < 0 || !current->stack_overflow_state()->reguard_stack((address) &continuation)) {
 570     // Forward exception to callee (leaving bci/bcp untouched) because (a) no
 571     // handler in this method, or (b) after a stack overflow there is not yet
 572     // enough stack space available to reprotect the stack.
 573     continuation = Interpreter::remove_activation_entry();
 574 #if COMPILER2_OR_JVMCI
 575     // Count this for compilation purposes
 576     h_method->interpreter_throwout_increment(THREAD);
 577 #endif
 578   } else {
 579     // handler in this method => change bci/bcp to handler bci/bcp and continue there
 580     handler_pc = h_method->code_base() + handler_bci;
 581     h_method->set_exception_handler_entered(handler_bci); // profiling
 582 #ifndef ZERO
 583     set_bcp_and_mdp(handler_pc, current);
 584     continuation = Interpreter::dispatch_table(vtos)[*handler_pc];
 585 #else
 586     continuation = (address)(intptr_t) handler_bci;
 587 #endif
 588   }
 589 
 590   // notify debugger of an exception catch
 591   // (this is good for exceptions caught in native methods as well)
 592   if (JvmtiExport::can_post_on_exceptions()) {
 593     JvmtiExport::notice_unwind_due_to_exception(current, h_method(), handler_pc, h_exception(), (handler_pc != nullptr));
 594   }
 595 
 596   current->set_vm_result_oop(h_exception());
 597   return continuation;
 598 JRT_END
 599 
 600 
 601 JRT_ENTRY(void, InterpreterRuntime::throw_pending_exception(JavaThread* current))
 602   assert(current->has_pending_exception(), "must only be called if there's an exception pending");
 603   // nothing to do - eventually we should remove this code entirely (see comments @ call sites)
 604 JRT_END
 605 
 606 
 607 JRT_ENTRY(void, InterpreterRuntime::throw_AbstractMethodError(JavaThread* current))
 608   THROW(vmSymbols::java_lang_AbstractMethodError());
 609 JRT_END
 610 
 611 // This method is called from the "abstract_entry" of the interpreter.
 612 // At that point, the arguments have already been removed from the stack
 613 // and therefore we don't have the receiver object at our fingertips. (Though,
 614 // on some platforms the receiver still resides in a register...). Thus,
 615 // we have no choice but print an error message not containing the receiver
 616 // type.
 617 JRT_ENTRY(void, InterpreterRuntime::throw_AbstractMethodErrorWithMethod(JavaThread* current,
 618                                                                         Method* missingMethod))
 619   ResourceMark rm(current);
 620   assert(missingMethod != nullptr, "sanity");
 621   methodHandle m(current, missingMethod);
 622   LinkResolver::throw_abstract_method_error(m, THREAD);
 623 JRT_END
 624 
 625 JRT_ENTRY(void, InterpreterRuntime::throw_AbstractMethodErrorVerbose(JavaThread* current,
 626                                                                      Klass* recvKlass,
 627                                                                      Method* missingMethod))
 628   ResourceMark rm(current);
 629   methodHandle mh = methodHandle(current, missingMethod);
 630   LinkResolver::throw_abstract_method_error(mh, recvKlass, THREAD);
 631 JRT_END
 632 
 633 
 634 JRT_ENTRY(void, InterpreterRuntime::throw_IncompatibleClassChangeError(JavaThread* current))
 635   THROW(vmSymbols::java_lang_IncompatibleClassChangeError());
 636 JRT_END
 637 
 638 JRT_ENTRY(void, InterpreterRuntime::throw_IncompatibleClassChangeErrorVerbose(JavaThread* current,
 639                                                                               Klass* recvKlass,
 640                                                                               Klass* interfaceKlass))
 641   ResourceMark rm(current);
 642   char buf[1000];
 643   buf[0] = '\0';
 644   jio_snprintf(buf, sizeof(buf),
 645                "Class %s does not implement the requested interface %s",
 646                recvKlass ? recvKlass->external_name() : "nullptr",
 647                interfaceKlass ? interfaceKlass->external_name() : "nullptr");
 648   THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(), buf);
 649 JRT_END
 650 
 651 JRT_ENTRY(void, InterpreterRuntime::throw_NullPointerException(JavaThread* current))
 652   THROW(vmSymbols::java_lang_NullPointerException());
 653 JRT_END
 654 
 655 //------------------------------------------------------------------------------------------------------------------------
 656 // Fields
 657 //
 658 
 659 void InterpreterRuntime::resolve_get_put(JavaThread* current, Bytecodes::Code bytecode) {
 660   JavaThread* THREAD = current;
 661   LastFrameAccessor last_frame(current);
 662   constantPoolHandle pool(current, last_frame.method()->constants());
 663   methodHandle m(current, last_frame.method());
 664 
 665   resolve_get_put(bytecode, last_frame.get_index_u2(bytecode), m, pool, StaticMode::initialize_klass_preemptable, CHECK_AND_CLEAR_PREEMPTED);
 666 }
 667 
 668 void InterpreterRuntime::resolve_get_put(Bytecodes::Code bytecode, int field_index,
 669                                          methodHandle& m,
 670                                          constantPoolHandle& pool,
 671                                          StaticMode static_mode, TRAPS) {
 672   fieldDescriptor info;
 673   bool is_put    = (bytecode == Bytecodes::_putfield  || bytecode == Bytecodes::_nofast_putfield ||
 674                     bytecode == Bytecodes::_putstatic);
 675   bool is_static = (bytecode == Bytecodes::_getstatic || bytecode == Bytecodes::_putstatic);
 676 
 677   {
 678     JvmtiHideSingleStepping jhss(THREAD);
 679     LinkResolver::resolve_field_access(info, pool, field_index,
 680                                        m, bytecode, static_mode, CHECK);
 681   } // end JvmtiHideSingleStepping
 682 
 683   // check if link resolution caused cpCache to be updated
 684   if (pool->resolved_field_entry_at(field_index)->is_resolved(bytecode)) return;
 685 
 686   // compute auxiliary field attributes
 687   TosState state  = as_TosState(info.field_type());
 688 
 689   // Resolution of put instructions on final fields is delayed. That is required so that
 690   // exceptions are thrown at the correct place (when the instruction is actually invoked).
 691   // If we do not resolve an instruction in the current pass, leaving the put_code
 692   // set to zero will cause the next put instruction to the same field to reresolve.
 693 
 694   // Resolution of put instructions to final instance fields with invalid updates (i.e.,
 695   // to final instance fields with updates originating from a method different than <init>)
 696   // is inhibited. A putfield instruction targeting an instance final field must throw
 697   // an IllegalAccessError if the instruction is not in an instance
 698   // initializer method <init>. If resolution were not inhibited, a putfield
 699   // in an initializer method could be resolved in the initializer. Subsequent
 700   // putfield instructions to the same field would then use cached information.
 701   // As a result, those instructions would not pass through the VM. That is,
 702   // checks in resolve_field_access() would not be executed for those instructions
 703   // and the required IllegalAccessError would not be thrown.
 704   //
 705   // Also, we need to delay resolving getstatic and putstatic instructions until the
 706   // class is initialized.  This is required so that access to the static
 707   // field will call the initialization function every time until the class
 708   // is completely initialized ala. in 2.17.5 in JVM Specification.
 709   InstanceKlass* klass = info.field_holder();
 710   bool uninitialized_static = is_static && !klass->is_initialized();
 711   bool has_initialized_final_update = info.field_holder()->major_version() >= 53 &&
 712                                       info.has_initialized_final_update();
 713   assert(!(has_initialized_final_update && !info.access_flags().is_final()), "Fields with initialized final updates must be final");
 714 
 715   Bytecodes::Code get_code = (Bytecodes::Code)0;
 716   Bytecodes::Code put_code = (Bytecodes::Code)0;
 717   if (!uninitialized_static) {
 718     get_code = ((is_static) ? Bytecodes::_getstatic : Bytecodes::_getfield);
 719     if ((is_put && !has_initialized_final_update) || !info.access_flags().is_final()) {
 720       put_code = ((is_static) ? Bytecodes::_putstatic : Bytecodes::_putfield);
 721     }
 722   }
 723 
 724   ResolvedFieldEntry* entry = pool->resolved_field_entry_at(field_index);
 725   entry->set_flags(info.access_flags().is_final(), info.access_flags().is_volatile());
 726   entry->fill_in(info.field_holder(), info.offset(),
 727                  checked_cast<u2>(info.index()), checked_cast<u1>(state),
 728                  static_cast<u1>(get_code), static_cast<u1>(put_code));
 729 }
 730 
 731 
 732 //------------------------------------------------------------------------------------------------------------------------
 733 // Synchronization
 734 //
 735 // The interpreter's synchronization code is factored out so that it can
 736 // be shared by method invocation and synchronized blocks.
 737 //%note synchronization_3
 738 
 739 //%note monitor_1
 740 JRT_ENTRY_NO_ASYNC(void, InterpreterRuntime::monitorenter(JavaThread* current, BasicObjectLock* elem))
 741 #ifdef ASSERT
 742   current->last_frame().interpreter_frame_verify_monitor(elem);
 743 #endif
 744   Handle h_obj(current, elem->obj());
 745   assert(Universe::heap()->is_in_or_null(h_obj()),
 746          "must be null or an object");
 747   ObjectSynchronizer::enter(h_obj, elem->lock(), current);
 748   assert(Universe::heap()->is_in_or_null(elem->obj()),
 749          "must be null or an object");
 750 #ifdef ASSERT
 751   if (!current->preempting()) current->last_frame().interpreter_frame_verify_monitor(elem);
 752 #endif
 753 JRT_END
 754 
 755 JRT_LEAF(void, InterpreterRuntime::monitorexit(BasicObjectLock* elem))
 756   oop obj = elem->obj();
 757   assert(Universe::heap()->is_in(obj), "must be an object");
 758   // The object could become unlocked through a JNI call, which we have no other checks for.
 759   // Give a fatal message if CheckJNICalls. Otherwise we ignore it.
 760   if (obj->is_unlocked()) {
 761     if (CheckJNICalls) {
 762       fatal("Object has been unlocked by JNI");
 763     }
 764     return;
 765   }
 766   ObjectSynchronizer::exit(obj, elem->lock(), JavaThread::current());
 767   // Free entry. If it is not cleared, the exception handling code will try to unlock the monitor
 768   // again at method exit or in the case of an exception.
 769   elem->set_obj(nullptr);
 770 JRT_END
 771 
 772 
 773 JRT_ENTRY(void, InterpreterRuntime::throw_illegal_monitor_state_exception(JavaThread* current))
 774   THROW(vmSymbols::java_lang_IllegalMonitorStateException());
 775 JRT_END
 776 
 777 
 778 JRT_ENTRY(void, InterpreterRuntime::new_illegal_monitor_state_exception(JavaThread* current))
 779   // Returns an illegal exception to install into the current thread. The
 780   // pending_exception flag is cleared so normal exception handling does not
 781   // trigger. Any current installed exception will be overwritten. This
 782   // method will be called during an exception unwind.
 783 
 784   assert(!HAS_PENDING_EXCEPTION, "no pending exception");
 785   Handle exception(current, current->vm_result_oop());
 786   assert(exception() != nullptr, "vm result should be set");
 787   current->set_vm_result_oop(nullptr); // clear vm result before continuing (may cause memory leaks and assert failures)
 788   exception = get_preinitialized_exception(vmClasses::IllegalMonitorStateException_klass(), CATCH);
 789   current->set_vm_result_oop(exception());
 790 JRT_END
 791 
 792 
 793 //------------------------------------------------------------------------------------------------------------------------
 794 // Invokes
 795 
 796 JRT_ENTRY(Bytecodes::Code, InterpreterRuntime::get_original_bytecode_at(JavaThread* current, Method* method, address bcp))
 797   return method->orig_bytecode_at(method->bci_from(bcp));
 798 JRT_END
 799 
 800 JRT_ENTRY(void, InterpreterRuntime::set_original_bytecode_at(JavaThread* current, Method* method, address bcp, Bytecodes::Code new_code))
 801   method->set_orig_bytecode_at(method->bci_from(bcp), new_code);
 802 JRT_END
 803 
 804 JRT_ENTRY(void, InterpreterRuntime::_breakpoint(JavaThread* current, Method* method, address bcp))
 805   JvmtiExport::post_raw_breakpoint(current, method, bcp);
 806 JRT_END
 807 
 808 void InterpreterRuntime::resolve_invoke(JavaThread* current, Bytecodes::Code bytecode) {
 809   LastFrameAccessor last_frame(current);
 810   // extract receiver from the outgoing argument list if necessary
 811   Handle receiver(current, nullptr);
 812   if (bytecode == Bytecodes::_invokevirtual || bytecode == Bytecodes::_invokeinterface ||
 813       bytecode == Bytecodes::_invokespecial) {
 814     ResourceMark rm(current);
 815     methodHandle m (current, last_frame.method());
 816     Bytecode_invoke call(m, last_frame.bci());
 817     Symbol* signature = call.signature();
 818     receiver = Handle(current, last_frame.callee_receiver(signature));
 819 
 820     assert(Universe::heap()->is_in_or_null(receiver()),
 821            "sanity check");
 822     assert(receiver.is_null() ||
 823            !Universe::heap()->is_in(receiver->klass()),
 824            "sanity check");
 825   }
 826 
 827   // resolve method
 828   CallInfo info;
 829   constantPoolHandle pool(current, last_frame.method()->constants());
 830 
 831   methodHandle resolved_method;
 832 
 833   int method_index = last_frame.get_index_u2(bytecode);
 834   { ProfileTrapsMark pt(current);
 835     JvmtiHideSingleStepping jhss(current);
 836     JavaThread* THREAD = current; // For exception macros.
 837     LinkResolver::resolve_invoke(info, receiver, pool,
 838                                  method_index, bytecode,
 839                                  StaticMode::initialize_klass_preemptable, CHECK_AND_CLEAR_PREEMPTED);
 840     resolved_method = methodHandle(current, info.resolved_method());
 841     ResourceMark rm(THREAD);
 842   } // end JvmtiHideSingleStepping
 843 
 844   update_invoke_cp_cache_entry(info, bytecode, resolved_method, pool, method_index);
 845 }
 846 
 847 void InterpreterRuntime::update_invoke_cp_cache_entry(CallInfo& info, Bytecodes::Code bytecode,
 848                                                       methodHandle& resolved_method,
 849                                                       constantPoolHandle& pool,
 850                                                       int method_index) {
 851   // Don't allow safepoints until the method is cached.
 852   NoSafepointVerifier nsv;
 853 
 854   // check if link resolution caused cpCache to be updated
 855   ConstantPoolCache* cache = pool->cache();
 856   if (cache->resolved_method_entry_at(method_index)->is_resolved(bytecode)) return;
 857 
 858 #ifdef ASSERT
 859   if (bytecode == Bytecodes::_invokeinterface) {
 860     if (resolved_method->method_holder() == vmClasses::Object_klass()) {
 861       // NOTE: THIS IS A FIX FOR A CORNER CASE in the JVM spec
 862       // (see also CallInfo::set_interface for details)
 863       assert(info.call_kind() == CallInfo::vtable_call ||
 864              info.call_kind() == CallInfo::direct_call, "");
 865       assert(resolved_method->is_final() || info.has_vtable_index(),
 866              "should have been set already");
 867     } else if (!resolved_method->has_itable_index()) {
 868       // Resolved something like CharSequence.toString.  Use vtable not itable.
 869       assert(info.call_kind() != CallInfo::itable_call, "");
 870     } else {
 871       // Setup itable entry
 872       assert(info.call_kind() == CallInfo::itable_call, "");
 873       int index = resolved_method->itable_index();
 874       assert(info.itable_index() == index, "");
 875     }
 876   } else if (bytecode == Bytecodes::_invokespecial) {
 877     assert(info.call_kind() == CallInfo::direct_call, "must be direct call");
 878   } else {
 879     assert(info.call_kind() == CallInfo::direct_call ||
 880            info.call_kind() == CallInfo::vtable_call, "");
 881   }
 882 #endif
 883   // Get sender and only set cpCache entry to resolved if it is not an
 884   // interface.  The receiver for invokespecial calls within interface
 885   // methods must be checked for every call.
 886   InstanceKlass* sender = pool->pool_holder();
 887 
 888   switch (info.call_kind()) {
 889   case CallInfo::direct_call:
 890     cache->set_direct_call(bytecode, method_index, resolved_method, sender->is_interface());
 891     break;
 892   case CallInfo::vtable_call:
 893     cache->set_vtable_call(bytecode, method_index, resolved_method, info.vtable_index());
 894     break;
 895   case CallInfo::itable_call:
 896     cache->set_itable_call(
 897       bytecode,
 898       method_index,
 899       info.resolved_klass(),
 900       resolved_method,
 901       info.itable_index());
 902     break;
 903   default:  ShouldNotReachHere();
 904   }
 905 }
 906 
 907 void InterpreterRuntime::cds_resolve_invoke(Bytecodes::Code bytecode, int method_index,
 908                                             constantPoolHandle& pool, TRAPS) {
 909   LinkInfo link_info(pool, method_index, bytecode, CHECK);
 910 
 911   if (!link_info.resolved_klass()->is_instance_klass() || InstanceKlass::cast(link_info.resolved_klass())->is_linked()) {
 912     CallInfo call_info;
 913     switch (bytecode) {
 914       case Bytecodes::_invokevirtual:   LinkResolver::cds_resolve_virtual_call  (call_info, link_info, CHECK); break;
 915       case Bytecodes::_invokeinterface: LinkResolver::cds_resolve_interface_call(call_info, link_info, CHECK); break;
 916       case Bytecodes::_invokespecial:   LinkResolver::cds_resolve_special_call  (call_info, link_info, CHECK); break;
 917 
 918       default: fatal("Unimplemented: %s", Bytecodes::name(bytecode));
 919     }
 920     methodHandle resolved_method(THREAD, call_info.resolved_method());
 921     guarantee(resolved_method->method_holder()->is_linked(), "");
 922     update_invoke_cp_cache_entry(call_info, bytecode, resolved_method, pool, method_index);
 923   } else {
 924     // FIXME: why a shared class is not linked yet?
 925     // Can't link it here since there are no guarantees it'll be prelinked on the next run.
 926     ResourceMark rm;
 927     InstanceKlass* resolved_iklass = InstanceKlass::cast(link_info.resolved_klass());
 928     log_info(cds, resolve)("Not resolved: class not linked: %s %s %s",
 929                            resolved_iklass->is_shared() ? "is_shared" : "",
 930                            resolved_iklass->init_state_name(),
 931                            resolved_iklass->external_name());
 932   }
 933 }
 934 
 935 // First time execution:  Resolve symbols, create a permanent MethodType object.
 936 void InterpreterRuntime::resolve_invokehandle(JavaThread* current) {
 937   const Bytecodes::Code bytecode = Bytecodes::_invokehandle;
 938   LastFrameAccessor last_frame(current);
 939 
 940   // resolve method
 941   CallInfo info;
 942   constantPoolHandle pool(current, last_frame.method()->constants());
 943   int method_index = last_frame.get_index_u2(bytecode);
 944   {
 945     JvmtiHideSingleStepping jhss(current);
 946     JavaThread* THREAD = current; // For exception macros.
 947     LinkResolver::resolve_invoke(info, Handle(), pool,
 948                                  method_index, bytecode,
 949                                  CHECK);
 950   } // end JvmtiHideSingleStepping
 951 
 952   pool->cache()->set_method_handle(method_index, info);
 953 }
 954 
 955 void InterpreterRuntime::cds_resolve_invokehandle(int raw_index,
 956                                                   constantPoolHandle& pool, TRAPS) {
 957   const Bytecodes::Code bytecode = Bytecodes::_invokehandle;
 958   CallInfo info;
 959   LinkResolver::resolve_invoke(info, Handle(), pool, raw_index, bytecode, CHECK);
 960 
 961   pool->cache()->set_method_handle(raw_index, info);
 962 }
 963 
 964 // First time execution:  Resolve symbols, create a permanent CallSite object.
 965 void InterpreterRuntime::resolve_invokedynamic(JavaThread* current) {
 966   LastFrameAccessor last_frame(current);
 967   const Bytecodes::Code bytecode = Bytecodes::_invokedynamic;
 968 
 969   // resolve method
 970   CallInfo info;
 971   constantPoolHandle pool(current, last_frame.method()->constants());
 972   int index = last_frame.get_index_u4(bytecode);
 973   {
 974     JvmtiHideSingleStepping jhss(current);
 975     JavaThread* THREAD = current; // For exception macros.
 976     LinkResolver::resolve_invoke(info, Handle(), pool,
 977                                  index, bytecode, CHECK);
 978   } // end JvmtiHideSingleStepping
 979 
 980   pool->cache()->set_dynamic_call(info, index);
 981 }
 982 
 983 void InterpreterRuntime::cds_resolve_invokedynamic(int raw_index,
 984                                                    constantPoolHandle& pool, TRAPS) {
 985   const Bytecodes::Code bytecode = Bytecodes::_invokedynamic;
 986   CallInfo info;
 987   LinkResolver::resolve_invoke(info, Handle(), pool, raw_index, bytecode, CHECK);
 988   pool->cache()->set_dynamic_call(info, raw_index);
 989 }
 990 
 991 // This function is the interface to the assembly code. It returns the resolved
 992 // cpCache entry.  This doesn't safepoint, but the helper routines safepoint.
 993 // This function will check for redefinition!
 994 JRT_ENTRY(void, InterpreterRuntime::resolve_from_cache(JavaThread* current, Bytecodes::Code bytecode)) {
 995   switch (bytecode) {
 996   case Bytecodes::_getstatic:
 997   case Bytecodes::_putstatic:
 998   case Bytecodes::_getfield:
 999   case Bytecodes::_putfield:
1000     resolve_get_put(current, bytecode);
1001     break;
1002   case Bytecodes::_invokevirtual:
1003   case Bytecodes::_invokespecial:
1004   case Bytecodes::_invokestatic:
1005   case Bytecodes::_invokeinterface:
1006     resolve_invoke(current, bytecode);
1007     break;
1008   case Bytecodes::_invokehandle:
1009     resolve_invokehandle(current);
1010     break;
1011   case Bytecodes::_invokedynamic:
1012     resolve_invokedynamic(current);
1013     break;
1014   default:
1015     fatal("unexpected bytecode: %s", Bytecodes::name(bytecode));
1016     break;
1017   }
1018 }
1019 JRT_END
1020 
1021 //------------------------------------------------------------------------------------------------------------------------
1022 // Miscellaneous
1023 
1024 
1025 nmethod* InterpreterRuntime::frequency_counter_overflow(JavaThread* current, address branch_bcp) {
1026   // Enable WXWrite: the function is called directly by interpreter.
1027   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, current));
1028 
1029   // frequency_counter_overflow_inner can throw async exception.
1030   nmethod* nm = frequency_counter_overflow_inner(current, branch_bcp);
1031   assert(branch_bcp != nullptr || nm == nullptr, "always returns null for non OSR requests");
1032   if (branch_bcp != nullptr && nm != nullptr) {
1033     // This was a successful request for an OSR nmethod.  Because
1034     // frequency_counter_overflow_inner ends with a safepoint check,
1035     // nm could have been unloaded so look it up again.  It's unsafe
1036     // to examine nm directly since it might have been freed and used
1037     // for something else.
1038     LastFrameAccessor last_frame(current);
1039     Method* method =  last_frame.method();
1040     int bci = method->bci_from(last_frame.bcp());
1041     nm = method->lookup_osr_nmethod_for(bci, CompLevel_none, false);
1042     BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
1043     if (nm != nullptr) {
1044       // in case the transition passed a safepoint we need to barrier this again
1045       if (!bs_nm->nmethod_osr_entry_barrier(nm)) {
1046         nm = nullptr;
1047       }
1048     }
1049   }
1050   if (nm != nullptr && current->is_interp_only_mode()) {
1051     // Normally we never get an nm if is_interp_only_mode() is true, because
1052     // policy()->event has a check for this and won't compile the method when
1053     // true. However, it's possible for is_interp_only_mode() to become true
1054     // during the compilation. We don't want to return the nm in that case
1055     // because we want to continue to execute interpreted.
1056     nm = nullptr;
1057   }
1058 #ifndef PRODUCT
1059   if (TraceOnStackReplacement) {
1060     if (nm != nullptr) {
1061       tty->print("OSR entry @ pc: " INTPTR_FORMAT ": ", p2i(nm->osr_entry()));
1062       nm->print();
1063     }
1064   }
1065 #endif
1066   return nm;
1067 }
1068 
1069 JRT_ENTRY(nmethod*,
1070           InterpreterRuntime::frequency_counter_overflow_inner(JavaThread* current, address branch_bcp))
1071   // use UnlockFlagSaver to clear and restore the _do_not_unlock_if_synchronized
1072   // flag, in case this method triggers classloading which will call into Java.
1073   UnlockFlagSaver fs(current);
1074 
1075   LastFrameAccessor last_frame(current);
1076   assert(last_frame.is_interpreted_frame(), "must come from interpreter");
1077   methodHandle method(current, last_frame.method());
1078   const int branch_bci = branch_bcp != nullptr ? method->bci_from(branch_bcp) : InvocationEntryBci;
1079   const int bci = branch_bcp != nullptr ? method->bci_from(last_frame.bcp()) : InvocationEntryBci;
1080 
1081   nmethod* osr_nm = CompilationPolicy::event(method, method, branch_bci, bci, CompLevel_none, nullptr, CHECK_NULL);
1082 
1083   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
1084   if (osr_nm != nullptr) {
1085     if (!bs_nm->nmethod_osr_entry_barrier(osr_nm)) {
1086       osr_nm = nullptr;
1087     }
1088   }
1089   return osr_nm;
1090 JRT_END
1091 
1092 JRT_LEAF(jint, InterpreterRuntime::bcp_to_di(Method* method, address cur_bcp))
1093   assert(ProfileInterpreter, "must be profiling interpreter");
1094   int bci = method->bci_from(cur_bcp);
1095   MethodData* mdo = method->method_data();
1096   if (mdo == nullptr)  return 0;
1097   return mdo->bci_to_di(bci);
1098 JRT_END
1099 
1100 #ifdef ASSERT
1101 JRT_LEAF(void, InterpreterRuntime::verify_mdp(Method* method, address bcp, address mdp))
1102   assert(ProfileInterpreter, "must be profiling interpreter");
1103 
1104   MethodData* mdo = method->method_data();
1105   assert(mdo != nullptr, "must not be null");
1106 
1107   int bci = method->bci_from(bcp);
1108 
1109   address mdp2 = mdo->bci_to_dp(bci);
1110   if (mdp != mdp2) {
1111     ResourceMark rm;
1112     tty->print_cr("FAILED verify : actual mdp %p   expected mdp %p @ bci %d", mdp, mdp2, bci);
1113     int current_di = mdo->dp_to_di(mdp);
1114     int expected_di  = mdo->dp_to_di(mdp2);
1115     tty->print_cr("  actual di %d   expected di %d", current_di, expected_di);
1116     int expected_approx_bci = mdo->data_at(expected_di)->bci();
1117     int approx_bci = -1;
1118     if (current_di >= 0) {
1119       approx_bci = mdo->data_at(current_di)->bci();
1120     }
1121     tty->print_cr("  actual bci is %d  expected bci %d", approx_bci, expected_approx_bci);
1122     mdo->print_on(tty);
1123     method->print_codes();
1124   }
1125   assert(mdp == mdp2, "wrong mdp");
1126 JRT_END
1127 #endif // ASSERT
1128 
1129 JRT_ENTRY(void, InterpreterRuntime::update_mdp_for_ret(JavaThread* current, int return_bci))
1130   assert(ProfileInterpreter, "must be profiling interpreter");
1131   ResourceMark rm(current);
1132   LastFrameAccessor last_frame(current);
1133   assert(last_frame.is_interpreted_frame(), "must come from interpreter");
1134   MethodData* h_mdo = last_frame.method()->method_data();
1135 
1136   // Grab a lock to ensure atomic access to setting the return bci and
1137   // the displacement.  This can block and GC, invalidating all naked oops.
1138   MutexLocker ml(RetData_lock);
1139 
1140   // ProfileData is essentially a wrapper around a derived oop, so we
1141   // need to take the lock before making any ProfileData structures.
1142   ProfileData* data = h_mdo->data_at(h_mdo->dp_to_di(last_frame.mdp()));
1143   guarantee(data != nullptr, "profile data must be valid");
1144   RetData* rdata = data->as_RetData();
1145   address new_mdp = rdata->fixup_ret(return_bci, h_mdo);
1146   last_frame.set_mdp(new_mdp);
1147 JRT_END
1148 
1149 JRT_ENTRY(MethodCounters*, InterpreterRuntime::build_method_counters(JavaThread* current, Method* m))
1150   return Method::build_method_counters(current, m);
1151 JRT_END
1152 
1153 
1154 JRT_ENTRY(void, InterpreterRuntime::at_safepoint(JavaThread* current))
1155   // We used to need an explicit preserve_arguments here for invoke bytecodes. However,
1156   // stack traversal automatically takes care of preserving arguments for invoke, so
1157   // this is no longer needed.
1158 
1159   // JRT_END does an implicit safepoint check, hence we are guaranteed to block
1160   // if this is called during a safepoint
1161 
1162   if (JvmtiExport::should_post_single_step()) {
1163     // This function is called by the interpreter when single stepping. Such single
1164     // stepping could unwind a frame. Then, it is important that we process any frames
1165     // that we might return into.
1166     StackWatermarkSet::before_unwind(current);
1167 
1168     // We are called during regular safepoints and when the VM is
1169     // single stepping. If any thread is marked for single stepping,
1170     // then we may have JVMTI work to do.
1171     LastFrameAccessor last_frame(current);
1172     JvmtiExport::at_single_stepping_point(current, last_frame.method(), last_frame.bcp());
1173   }
1174 JRT_END
1175 
1176 JRT_LEAF(void, InterpreterRuntime::at_unwind(JavaThread* current))
1177   assert(current == JavaThread::current(), "pre-condition");
1178   // This function is called by the interpreter when the return poll found a reason
1179   // to call the VM. The reason could be that we are returning into a not yet safe
1180   // to access frame. We handle that below.
1181   // Note that this path does not check for single stepping, because we do not want
1182   // to single step when unwinding frames for an exception being thrown. Instead,
1183   // such single stepping code will use the safepoint table, which will use the
1184   // InterpreterRuntime::at_safepoint callback.
1185   StackWatermarkSet::before_unwind(current);
1186 JRT_END
1187 
1188 JRT_ENTRY(void, InterpreterRuntime::post_field_access(JavaThread* current, oopDesc* obj,
1189                                                       ResolvedFieldEntry *entry))
1190 
1191   // check the access_flags for the field in the klass
1192 
1193   InstanceKlass* ik = entry->field_holder();
1194   int index = entry->field_index();
1195   if (!ik->field_status(index).is_access_watched()) return;
1196 
1197   bool is_static = (obj == nullptr);
1198   HandleMark hm(current);
1199 
1200   Handle h_obj;
1201   if (!is_static) {
1202     // non-static field accessors have an object, but we need a handle
1203     h_obj = Handle(current, obj);
1204   }
1205   InstanceKlass* field_holder = entry->field_holder(); // HERE
1206   jfieldID fid = jfieldIDWorkaround::to_jfieldID(field_holder, entry->field_offset(), is_static);
1207   LastFrameAccessor last_frame(current);
1208   JvmtiExport::post_field_access(current, last_frame.method(), last_frame.bcp(), field_holder, h_obj, fid);
1209 JRT_END
1210 
1211 JRT_ENTRY(void, InterpreterRuntime::post_field_modification(JavaThread* current, oopDesc* obj,
1212                                                             ResolvedFieldEntry *entry, jvalue *value))
1213 
1214   InstanceKlass* ik = entry->field_holder();
1215 
1216   // check the access_flags for the field in the klass
1217   int index = entry->field_index();
1218   // bail out if field modifications are not watched
1219   if (!ik->field_status(index).is_modification_watched()) return;
1220 
1221   char sig_type = '\0';
1222 
1223   switch((TosState)entry->tos_state()) {
1224     case btos: sig_type = JVM_SIGNATURE_BYTE;    break;
1225     case ztos: sig_type = JVM_SIGNATURE_BOOLEAN; break;
1226     case ctos: sig_type = JVM_SIGNATURE_CHAR;    break;
1227     case stos: sig_type = JVM_SIGNATURE_SHORT;   break;
1228     case itos: sig_type = JVM_SIGNATURE_INT;     break;
1229     case ftos: sig_type = JVM_SIGNATURE_FLOAT;   break;
1230     case atos: sig_type = JVM_SIGNATURE_CLASS;   break;
1231     case ltos: sig_type = JVM_SIGNATURE_LONG;    break;
1232     case dtos: sig_type = JVM_SIGNATURE_DOUBLE;  break;
1233     default:  ShouldNotReachHere(); return;
1234   }
1235   bool is_static = (obj == nullptr);
1236 
1237   HandleMark hm(current);
1238   jfieldID fid = jfieldIDWorkaround::to_jfieldID(ik, entry->field_offset(), is_static);
1239   jvalue fvalue;
1240 #ifdef _LP64
1241   fvalue = *value;
1242 #else
1243   // Long/double values are stored unaligned and also noncontiguously with
1244   // tagged stacks.  We can't just do a simple assignment even in the non-
1245   // J/D cases because a C++ compiler is allowed to assume that a jvalue is
1246   // 8-byte aligned, and interpreter stack slots are only 4-byte aligned.
1247   // We assume that the two halves of longs/doubles are stored in interpreter
1248   // stack slots in platform-endian order.
1249   jlong_accessor u;
1250   jint* newval = (jint*)value;
1251   u.words[0] = newval[0];
1252   u.words[1] = newval[Interpreter::stackElementWords]; // skip if tag
1253   fvalue.j = u.long_value;
1254 #endif // _LP64
1255 
1256   Handle h_obj;
1257   if (!is_static) {
1258     // non-static field accessors have an object, but we need a handle
1259     h_obj = Handle(current, obj);
1260   }
1261 
1262   LastFrameAccessor last_frame(current);
1263   JvmtiExport::post_raw_field_modification(current, last_frame.method(), last_frame.bcp(), ik, h_obj,
1264                                            fid, sig_type, &fvalue);
1265 JRT_END
1266 
1267 JRT_ENTRY(void, InterpreterRuntime::post_method_entry(JavaThread* current))
1268   LastFrameAccessor last_frame(current);
1269   JvmtiExport::post_method_entry(current, last_frame.method(), last_frame.get_frame());
1270 JRT_END
1271 
1272 
1273 // This is a JRT_BLOCK_ENTRY because we have to stash away the return oop
1274 // before transitioning to VM, and restore it after transitioning back
1275 // to Java. The return oop at the top-of-stack, is not walked by the GC.
1276 JRT_BLOCK_ENTRY(void, InterpreterRuntime::post_method_exit(JavaThread* current))
1277   LastFrameAccessor last_frame(current);
1278   JvmtiExport::post_method_exit(current, last_frame.method(), last_frame.get_frame());
1279 JRT_END
1280 
1281 JRT_LEAF(int, InterpreterRuntime::interpreter_contains(address pc))
1282 {
1283   return (Interpreter::contains(Continuation::get_top_return_pc_post_barrier(JavaThread::current(), pc)) ? 1 : 0);
1284 }
1285 JRT_END
1286 
1287 
1288 // Implementation of SignatureHandlerLibrary
1289 
1290 #ifndef SHARING_FAST_NATIVE_FINGERPRINTS
1291 // Dummy definition (else normalization method is defined in CPU
1292 // dependent code)
1293 uint64_t InterpreterRuntime::normalize_fast_native_fingerprint(uint64_t fingerprint) {
1294   return fingerprint;
1295 }
1296 #endif
1297 
1298 address SignatureHandlerLibrary::set_handler_blob() {
1299   BufferBlob* handler_blob = BufferBlob::create("native signature handlers", blob_size);
1300   if (handler_blob == nullptr) {
1301     return nullptr;
1302   }
1303   address handler = handler_blob->code_begin();
1304   _handler_blob = handler_blob;
1305   _handler = handler;
1306   return handler;
1307 }
1308 
1309 void SignatureHandlerLibrary::initialize() {
1310   if (_fingerprints != nullptr) {
1311     return;
1312   }
1313   if (set_handler_blob() == nullptr) {
1314     vm_exit_out_of_memory(blob_size, OOM_MALLOC_ERROR, "native signature handlers");
1315   }
1316 
1317   BufferBlob* bb = BufferBlob::create("Signature Handler Temp Buffer",
1318                                       SignatureHandlerLibrary::buffer_size);
1319   _buffer = bb->code_begin();
1320 
1321   _fingerprints = new (mtCode) GrowableArray<uint64_t>(32, mtCode);
1322   _handlers     = new (mtCode) GrowableArray<address>(32, mtCode);
1323 }
1324 
1325 address SignatureHandlerLibrary::set_handler(CodeBuffer* buffer) {
1326   address handler   = _handler;
1327   int     insts_size = buffer->pure_insts_size();
1328   if (handler + insts_size > _handler_blob->code_end()) {
1329     // get a new handler blob
1330     handler = set_handler_blob();
1331   }
1332   if (handler != nullptr) {
1333     memcpy(handler, buffer->insts_begin(), insts_size);
1334     pd_set_handler(handler);
1335     ICache::invalidate_range(handler, insts_size);
1336     _handler = handler + insts_size;
1337   }
1338   return handler;
1339 }
1340 
1341 void SignatureHandlerLibrary::add(const methodHandle& method) {
1342   if (method->signature_handler() == nullptr) {
1343     // use slow signature handler if we can't do better
1344     int handler_index = -1;
1345     // check if we can use customized (fast) signature handler
1346     if (UseFastSignatureHandlers && method->size_of_parameters() <= Fingerprinter::fp_max_size_of_parameters) {
1347       // use customized signature handler
1348       MutexLocker mu(SignatureHandlerLibrary_lock);
1349       // make sure data structure is initialized
1350       initialize();
1351       // lookup method signature's fingerprint
1352       uint64_t fingerprint = Fingerprinter(method).fingerprint();
1353       // allow CPU dependent code to optimize the fingerprints for the fast handler
1354       fingerprint = InterpreterRuntime::normalize_fast_native_fingerprint(fingerprint);
1355       handler_index = _fingerprints->find(fingerprint);
1356       // create handler if necessary
1357       if (handler_index < 0) {
1358         ResourceMark rm;
1359         ptrdiff_t align_offset = align_up(_buffer, CodeEntryAlignment) - (address)_buffer;
1360         CodeBuffer buffer((address)(_buffer + align_offset),
1361                           checked_cast<int>(SignatureHandlerLibrary::buffer_size - align_offset));
1362         InterpreterRuntime::SignatureHandlerGenerator(method, &buffer).generate(fingerprint);
1363         // copy into code heap
1364         address handler = set_handler(&buffer);
1365         if (handler == nullptr) {
1366           // use slow signature handler (without memorizing it in the fingerprints)
1367         } else {
1368           // debugging support
1369           if (PrintSignatureHandlers && (handler != Interpreter::slow_signature_handler())) {
1370             ttyLocker ttyl;
1371             tty->cr();
1372             tty->print_cr("argument handler #%d for: %s %s (fingerprint = " UINT64_FORMAT ", %d bytes generated)",
1373                           _handlers->length(),
1374                           (method->is_static() ? "static" : "receiver"),
1375                           method->name_and_sig_as_C_string(),
1376                           fingerprint,
1377                           buffer.insts_size());
1378             if (buffer.insts_size() > 0) {
1379               Disassembler::decode(handler, handler + buffer.insts_size(), tty
1380                                    NOT_PRODUCT(COMMA &buffer.asm_remarks()));
1381             }
1382 #ifndef PRODUCT
1383             address rh_begin = Interpreter::result_handler(method()->result_type());
1384             if (CodeCache::contains(rh_begin)) {
1385               // else it might be special platform dependent values
1386               tty->print_cr(" --- associated result handler ---");
1387               address rh_end = rh_begin;
1388               while (*(int*)rh_end != 0) {
1389                 rh_end += sizeof(int);
1390               }
1391               Disassembler::decode(rh_begin, rh_end);
1392             } else {
1393               tty->print_cr(" associated result handler: " PTR_FORMAT, p2i(rh_begin));
1394             }
1395 #endif
1396           }
1397           // add handler to library
1398           _fingerprints->append(fingerprint);
1399           _handlers->append(handler);
1400           // set handler index
1401           assert(_fingerprints->length() == _handlers->length(), "sanity check");
1402           handler_index = _fingerprints->length() - 1;
1403         }
1404       }
1405       // Set handler under SignatureHandlerLibrary_lock
1406       if (handler_index < 0) {
1407         // use generic signature handler
1408         method->set_signature_handler(Interpreter::slow_signature_handler());
1409       } else {
1410         // set handler
1411         method->set_signature_handler(_handlers->at(handler_index));
1412       }
1413     } else {
1414       DEBUG_ONLY(JavaThread::current()->check_possible_safepoint());
1415       // use generic signature handler
1416       method->set_signature_handler(Interpreter::slow_signature_handler());
1417     }
1418   }
1419 #ifdef ASSERT
1420   int handler_index = -1;
1421   int fingerprint_index = -2;
1422   {
1423     // '_handlers' and '_fingerprints' are 'GrowableArray's and are NOT synchronized
1424     // in any way if accessed from multiple threads. To avoid races with another
1425     // thread which may change the arrays in the above, mutex protected block, we
1426     // have to protect this read access here with the same mutex as well!
1427     MutexLocker mu(SignatureHandlerLibrary_lock);
1428     if (_handlers != nullptr) {
1429       handler_index = _handlers->find(method->signature_handler());
1430       uint64_t fingerprint = Fingerprinter(method).fingerprint();
1431       fingerprint = InterpreterRuntime::normalize_fast_native_fingerprint(fingerprint);
1432       fingerprint_index = _fingerprints->find(fingerprint);
1433     }
1434   }
1435   assert(method->signature_handler() == Interpreter::slow_signature_handler() ||
1436          handler_index == fingerprint_index, "sanity check");
1437 #endif // ASSERT
1438 }
1439 
1440 BufferBlob*              SignatureHandlerLibrary::_handler_blob = nullptr;
1441 address                  SignatureHandlerLibrary::_handler      = nullptr;
1442 GrowableArray<uint64_t>* SignatureHandlerLibrary::_fingerprints = nullptr;
1443 GrowableArray<address>*  SignatureHandlerLibrary::_handlers     = nullptr;
1444 address                  SignatureHandlerLibrary::_buffer       = nullptr;
1445 
1446 
1447 JRT_ENTRY(void, InterpreterRuntime::prepare_native_call(JavaThread* current, Method* method))
1448   methodHandle m(current, method);
1449   assert(m->is_native(), "sanity check");
1450   // lookup native function entry point if it doesn't exist
1451   if (!m->has_native_function()) {
1452     NativeLookup::lookup(m, CHECK);
1453   }
1454   // make sure signature handler is installed
1455   SignatureHandlerLibrary::add(m);
1456   // The interpreter entry point checks the signature handler first,
1457   // before trying to fetch the native entry point and klass mirror.
1458   // We must set the signature handler last, so that multiple processors
1459   // preparing the same method will be sure to see non-null entry & mirror.
1460 JRT_END
1461 
1462 #if defined(IA32) || defined(AMD64) || defined(ARM)
1463 JRT_LEAF(void, InterpreterRuntime::popframe_move_outgoing_args(JavaThread* current, void* src_address, void* dest_address))
1464   assert(current == JavaThread::current(), "pre-condition");
1465   if (src_address == dest_address) {
1466     return;
1467   }
1468   ResourceMark rm;
1469   LastFrameAccessor last_frame(current);
1470   assert(last_frame.is_interpreted_frame(), "");
1471   jint bci = last_frame.bci();
1472   methodHandle mh(current, last_frame.method());
1473   Bytecode_invoke invoke(mh, bci);
1474   ArgumentSizeComputer asc(invoke.signature());
1475   int size_of_arguments = (asc.size() + (invoke.has_receiver() ? 1 : 0)); // receiver
1476   Copy::conjoint_jbytes(src_address, dest_address,
1477                        size_of_arguments * Interpreter::stackElementSize);
1478 JRT_END
1479 #endif
1480 
1481 #if INCLUDE_JVMTI
1482 // This is a support of the JVMTI PopFrame interface.
1483 // Make sure it is an invokestatic of a polymorphic intrinsic that has a member_name argument
1484 // and return it as a vm_result_oop so that it can be reloaded in the list of invokestatic parameters.
1485 // The member_name argument is a saved reference (in local#0) to the member_name.
1486 // For backward compatibility with some JDK versions (7, 8) it can also be a direct method handle.
1487 // FIXME: remove DMH case after j.l.i.InvokerBytecodeGenerator code shape is updated.
1488 JRT_ENTRY(void, InterpreterRuntime::member_name_arg_or_null(JavaThread* current, address member_name,
1489                                                             Method* method, address bcp))
1490   Bytecodes::Code code = Bytecodes::code_at(method, bcp);
1491   if (code != Bytecodes::_invokestatic) {
1492     return;
1493   }
1494   ConstantPool* cpool = method->constants();
1495   int cp_index = Bytes::get_native_u2(bcp + 1);
1496   Symbol* cname = cpool->klass_name_at(cpool->klass_ref_index_at(cp_index, code));
1497   Symbol* mname = cpool->name_ref_at(cp_index, code);
1498 
1499   if (MethodHandles::has_member_arg(cname, mname)) {
1500     oop member_name_oop = cast_to_oop(member_name);
1501     if (java_lang_invoke_DirectMethodHandle::is_instance(member_name_oop)) {
1502       // FIXME: remove after j.l.i.InvokerBytecodeGenerator code shape is updated.
1503       member_name_oop = java_lang_invoke_DirectMethodHandle::member(member_name_oop);
1504     }
1505     current->set_vm_result_oop(member_name_oop);
1506   } else {
1507     current->set_vm_result_oop(nullptr);
1508   }
1509 JRT_END
1510 #endif // INCLUDE_JVMTI
1511 
1512 #ifndef PRODUCT
1513 // This must be a JRT_LEAF function because the interpreter must save registers on x86 to
1514 // call this, which changes rsp and makes the interpreter's expression stack not walkable.
1515 // The generated code still uses call_VM because that will set up the frame pointer for
1516 // bcp and method.
1517 JRT_LEAF(intptr_t, InterpreterRuntime::trace_bytecode(JavaThread* current, intptr_t preserve_this_value, intptr_t tos, intptr_t tos2))
1518   assert(current == JavaThread::current(), "pre-condition");
1519   LastFrameAccessor last_frame(current);
1520   assert(last_frame.is_interpreted_frame(), "must be an interpreted frame");
1521   methodHandle mh(current, last_frame.method());
1522   BytecodeTracer::trace_interpreter(mh, last_frame.bcp(), tos, tos2);
1523   return preserve_this_value;
1524 JRT_END
1525 #endif // !PRODUCT