1 /*
   2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/systemDictionary.hpp"
  27 #include "classfile/vmSymbols.hpp"
  28 #include "code/nmethod.hpp"
  29 #include "compiler/compileBroker.hpp"
  30 #include "interpreter/interpreter.hpp"
  31 #include "interpreter/linkResolver.hpp"
  32 #include "memory/universe.hpp"
  33 #include "oops/method.inline.hpp"
  34 #include "oops/oop.inline.hpp"
  35 #include "prims/jniCheck.hpp"
  36 #include "compiler/compilationPolicy.hpp"
  37 #include "runtime/handles.inline.hpp"
  38 #include "runtime/interfaceSupport.inline.hpp"
  39 #include "runtime/javaCalls.hpp"
  40 #include "runtime/jniHandles.inline.hpp"
  41 #include "runtime/mutexLocker.hpp"
  42 #include "runtime/os.inline.hpp"
  43 #include "runtime/sharedRuntime.hpp"
  44 #include "runtime/signature.hpp"
  45 #include "runtime/stubRoutines.hpp"
  46 #include "runtime/thread.inline.hpp"
  47 
  48 // -----------------------------------------------------
  49 // Implementation of JavaCallWrapper
  50 
  51 JavaCallWrapper::JavaCallWrapper(const methodHandle& callee_method, Handle receiver, JavaValue* result, TRAPS) {
  52   JavaThread* thread = (JavaThread *)THREAD;
  53   bool clear_pending_exception = true;
  54 
  55   guarantee(thread->is_Java_thread(), "crucial check - the VM thread cannot and must not escape to Java code");
  56   assert(!thread->owns_locks(), "must release all locks when leaving VM");
  57   guarantee(thread->can_call_java(), "cannot make java calls from the native compiler");
  58   _result   = result;
  59 
  60   // Allocate handle block for Java code. This must be done before we change thread_state to _thread_in_Java_or_stub,
  61   // since it can potentially block.
  62   JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(thread);
  63 
  64   // After this, we are official in JavaCode. This needs to be done before we change any of the thread local
  65   // info, since we cannot find oops before the new information is set up completely.
  66   ThreadStateTransition::transition(thread, _thread_in_vm, _thread_in_Java);
  67 
  68   // Make sure that we handle asynchronous stops and suspends _before_ we clear all thread state
  69   // in JavaCallWrapper::JavaCallWrapper(). This way, we can decide if we need to do any pd actions
  70   // to prepare for stop/suspend (flush register windows on sparcs, cache sp, or other state).
  71   if (thread->has_special_runtime_exit_condition()) {
  72     thread->handle_special_runtime_exit_condition();
  73     if (HAS_PENDING_EXCEPTION) {
  74       clear_pending_exception = false;
  75     }
  76   }
  77 
  78 
  79   // Make sure to set the oop's after the thread transition - since we can block there. No one is GC'ing
  80   // the JavaCallWrapper before the entry frame is on the stack.
  81   _callee_method = callee_method();
  82   _receiver = receiver();
  83 
  84 #ifdef CHECK_UNHANDLED_OOPS
  85   THREAD->allow_unhandled_oop(&_receiver);
  86 #endif // CHECK_UNHANDLED_OOPS
  87 
  88   _thread       = (JavaThread *)thread;
  89   _handles      = _thread->active_handles();    // save previous handle block & Java frame linkage
  90 
  91   // For the profiler, the last_Java_frame information in thread must always be in
  92   // legal state. We have no last Java frame if last_Java_sp == NULL so
  93   // the valid transition is to clear _last_Java_sp and then reset the rest of
  94   // the (platform specific) state.
  95 
  96   _anchor.copy(_thread->frame_anchor());
  97   _thread->frame_anchor()->clear();
  98 
  99   debug_only(_thread->inc_java_call_counter());
 100   _thread->set_active_handles(new_handles);     // install new handle block and reset Java frame linkage
 101 
 102   assert (_thread->thread_state() != _thread_in_native, "cannot set native pc to NULL");
 103 
 104   // clear any pending exception in thread (native calls start with no exception pending)
 105   if(clear_pending_exception) {
 106     _thread->clear_pending_exception();
 107   }
 108 
 109   if (_anchor.last_Java_sp() == NULL) {
 110     _thread->record_base_of_stack_pointer();
 111   }
 112 }
 113 
 114 
 115 JavaCallWrapper::~JavaCallWrapper() {
 116   assert(_thread == JavaThread::current(), "must still be the same thread");
 117 
 118   // restore previous handle block & Java frame linkage
 119   JNIHandleBlock *_old_handles = _thread->active_handles();
 120   _thread->set_active_handles(_handles);
 121 
 122   _thread->frame_anchor()->zap();
 123 
 124   debug_only(_thread->dec_java_call_counter());
 125 
 126   if (_anchor.last_Java_sp() == NULL) {
 127     _thread->set_base_of_stack_pointer(NULL);
 128   }
 129 
 130 
 131   // Old thread-local info. has been restored. We are not back in the VM.
 132   ThreadStateTransition::transition_from_java(_thread, _thread_in_vm);
 133 
 134   // State has been restored now make the anchor frame visible for the profiler.
 135   // Do this after the transition because this allows us to put an assert
 136   // the Java->vm transition which checks to see that stack is not walkable
 137   // on sparc/ia64 which will catch violations of the reseting of last_Java_frame
 138   // invariants (i.e. _flags always cleared on return to Java)
 139 
 140   _thread->frame_anchor()->copy(&_anchor);
 141 
 142   // Release handles after we are marked as being inside the VM again, since this
 143   // operation might block
 144   JNIHandleBlock::release_block(_old_handles, _thread);
 145 }
 146 
 147 
 148 void JavaCallWrapper::oops_do(OopClosure* f) {
 149   f->do_oop((oop*)&_receiver);
 150   handles()->oops_do(f);
 151 }
 152 
 153 
 154 // Helper methods
 155 static BasicType runtime_type_from(JavaValue* result) {
 156   switch (result->get_type()) {
 157     case T_BOOLEAN: // fall through
 158     case T_CHAR   : // fall through
 159     case T_SHORT  : // fall through
 160     case T_INT    : // fall through
 161 #ifndef _LP64
 162     case T_OBJECT : // fall through
 163     case T_ARRAY  : // fall through
 164 #endif
 165     case T_BYTE   : // fall through
 166     case T_VOID   : return T_INT;
 167     case T_LONG   : return T_LONG;
 168     case T_FLOAT  : return T_FLOAT;
 169     case T_DOUBLE : return T_DOUBLE;
 170 #ifdef _LP64
 171     case T_ARRAY  : // fall through
 172     case T_OBJECT:  return T_OBJECT;
 173 #endif
 174     default:
 175       ShouldNotReachHere();
 176       return T_ILLEGAL;
 177   }
 178 }
 179 
 180 // ============ Virtual calls ============
 181 
 182 void JavaCalls::call_virtual(JavaValue* result, Klass* spec_klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS) {
 183   CallInfo callinfo;
 184   Handle receiver = args->receiver();
 185   Klass* recvrKlass = receiver.is_null() ? (Klass*)NULL : receiver->klass();
 186   LinkInfo link_info(spec_klass, name, signature);
 187   LinkResolver::resolve_virtual_call(
 188           callinfo, receiver, recvrKlass, link_info, true, CHECK);
 189   methodHandle method = callinfo.selected_method();
 190   assert(method.not_null(), "should have thrown exception");
 191 
 192   // Invoke the method
 193   JavaCalls::call(result, method, args, CHECK);
 194 }
 195 
 196 
 197 void JavaCalls::call_virtual(JavaValue* result, Handle receiver, Klass* spec_klass, Symbol* name, Symbol* signature, TRAPS) {
 198   JavaCallArguments args(receiver);
 199   call_virtual(result, spec_klass, name, signature, &args, CHECK);
 200 }
 201 
 202 
 203 void JavaCalls::call_virtual(JavaValue* result, Handle receiver, Klass* spec_klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS) {
 204   JavaCallArguments args(receiver);
 205   args.push_oop(arg1);
 206   call_virtual(result, spec_klass, name, signature, &args, CHECK);
 207 }
 208 
 209 
 210 
 211 void JavaCalls::call_virtual(JavaValue* result, Handle receiver, Klass* spec_klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS) {
 212   JavaCallArguments args(receiver);
 213   args.push_oop(arg1);
 214   args.push_oop(arg2);
 215   call_virtual(result, spec_klass, name, signature, &args, CHECK);
 216 }
 217 
 218 
 219 // ============ Special calls ============
 220 
 221 void JavaCalls::call_special(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS) {
 222   CallInfo callinfo;
 223   LinkInfo link_info(klass, name, signature);
 224   LinkResolver::resolve_special_call(callinfo, args->receiver(), link_info, CHECK);
 225   methodHandle method = callinfo.selected_method();
 226   assert(method.not_null(), "should have thrown exception");
 227 
 228   // Invoke the method
 229   JavaCalls::call(result, method, args, CHECK);
 230 }
 231 
 232 
 233 void JavaCalls::call_special(JavaValue* result, Handle receiver, Klass* klass, Symbol* name, Symbol* signature, TRAPS) {
 234   JavaCallArguments args(receiver);
 235   call_special(result, klass, name, signature, &args, CHECK);
 236 }
 237 
 238 
 239 void JavaCalls::call_special(JavaValue* result, Handle receiver, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS) {
 240   JavaCallArguments args(receiver);
 241   args.push_oop(arg1);
 242   call_special(result, klass, name, signature, &args, CHECK);
 243 }
 244 
 245 
 246 void JavaCalls::call_special(JavaValue* result, Handle receiver, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS) {
 247   JavaCallArguments args(receiver);
 248   args.push_oop(arg1);
 249   args.push_oop(arg2);
 250   call_special(result, klass, name, signature, &args, CHECK);
 251 }
 252 
 253 
 254 // ============ Static calls ============
 255 
 256 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS) {
 257   CallInfo callinfo;
 258   LinkInfo link_info(klass, name, signature);
 259   LinkResolver::resolve_static_call(callinfo, link_info, true, CHECK);
 260   methodHandle method = callinfo.selected_method();
 261   assert(method.not_null(), "should have thrown exception");
 262 
 263   // Invoke the method
 264   JavaCalls::call(result, method, args, CHECK);
 265 }
 266 
 267 
 268 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, TRAPS) {
 269   JavaCallArguments args;
 270   call_static(result, klass, name, signature, &args, CHECK);
 271 }
 272 
 273 
 274 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS) {
 275   JavaCallArguments args(arg1);
 276   call_static(result, klass, name, signature, &args, CHECK);
 277 }
 278 
 279 
 280 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS) {
 281   JavaCallArguments args;
 282   args.push_oop(arg1);
 283   args.push_oop(arg2);
 284   call_static(result, klass, name, signature, &args, CHECK);
 285 }
 286 
 287 
 288 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, Handle arg3, TRAPS) {
 289   JavaCallArguments args;
 290   args.push_oop(arg1);
 291   args.push_oop(arg2);
 292   args.push_oop(arg3);
 293   call_static(result, klass, name, signature, &args, CHECK);
 294 }
 295 
 296 // ============ allocate and initialize new object instance ============
 297 
 298 Handle JavaCalls::construct_new_instance(InstanceKlass* klass, Symbol* constructor_signature, JavaCallArguments* args, TRAPS) {
 299   klass->initialize(CHECK_NH); // Quick no-op if already initialized.
 300   Handle obj = klass->allocate_instance_handle(CHECK_NH);
 301   JavaValue void_result(T_VOID);
 302   args->set_receiver(obj); // inserts <obj> as the first argument.
 303   JavaCalls::call_special(&void_result, klass,
 304                           vmSymbols::object_initializer_name(),
 305                           constructor_signature, args, CHECK_NH);
 306   // Already returned a Null Handle if any exception is pending.
 307   return obj;
 308 }
 309 
 310 Handle JavaCalls::construct_new_instance(InstanceKlass* klass, Symbol* constructor_signature, TRAPS) {
 311   JavaCallArguments args;
 312   return JavaCalls::construct_new_instance(klass, constructor_signature, &args, THREAD);
 313 }
 314 
 315 Handle JavaCalls::construct_new_instance(InstanceKlass* klass, Symbol* constructor_signature, Handle arg1, TRAPS) {
 316   JavaCallArguments args;
 317   args.push_oop(arg1);
 318   return JavaCalls::construct_new_instance(klass, constructor_signature, &args, THREAD);
 319 }
 320 
 321 Handle JavaCalls::construct_new_instance(InstanceKlass* klass, Symbol* constructor_signature, Handle arg1, Handle arg2, TRAPS) {
 322   JavaCallArguments args;
 323   args.push_oop(arg1);
 324   args.push_oop(arg2);
 325   return JavaCalls::construct_new_instance(klass, constructor_signature, &args, THREAD);
 326 }
 327 
 328 // -------------------------------------------------
 329 // Implementation of JavaCalls (low level)
 330 
 331 
 332 void JavaCalls::call(JavaValue* result, const methodHandle& method, JavaCallArguments* args, TRAPS) {
 333   // Check if we need to wrap a potential OS exception handler around thread
 334   // This is used for e.g. Win32 structured exception handlers
 335   assert(THREAD->is_Java_thread(), "only JavaThreads can make JavaCalls");
 336   // Need to wrap each and every time, since there might be native code down the
 337   // stack that has installed its own exception handlers
 338   os::os_exception_wrapper(call_helper, result, method, args, THREAD);
 339 }
 340 
 341 void JavaCalls::call_helper(JavaValue* result, const methodHandle& method, JavaCallArguments* args, TRAPS) {
 342 
 343   JavaThread* thread = (JavaThread*)THREAD;
 344   assert(thread->is_Java_thread(), "must be called by a java thread");
 345   assert(method.not_null(), "must have a method to call");
 346   assert(!SafepointSynchronize::is_at_safepoint(), "call to Java code during VM operation");
 347   assert(!thread->handle_area()->no_handle_mark_active(), "cannot call out to Java here");
 348 
 349 #if INCLUDE_JVMCI
 350   // Gets the nmethod (if any) that should be called instead of normal target
 351   nmethod* alternative_target = args->alternative_target();
 352   if (alternative_target == NULL) {
 353 #endif
 354 // Verify the arguments
 355 
 356   if (CheckJNICalls)  {
 357     args->verify(method, result->get_type());
 358   }
 359   else debug_only(args->verify(method, result->get_type()));
 360 #if INCLUDE_JVMCI
 361   }
 362 #else
 363 
 364   // Ignore call if method is empty
 365   if (method->is_empty_method()) {
 366     assert(result->get_type() == T_VOID, "an empty method must return a void value");
 367     return;
 368   }
 369 #endif
 370 
 371 #ifdef ASSERT
 372   { InstanceKlass* holder = method->method_holder();
 373     // A klass might not be initialized since JavaCall's might be used during the executing of
 374     // the <clinit>. For example, a Thread.start might start executing on an object that is
 375     // not fully initialized! (bad Java programming style)
 376     assert(holder->is_linked(), "rewriting must have taken place");
 377   }
 378 #endif
 379 
 380   CompilationPolicy::compile_if_required(method, CHECK);
 381 
 382   // Since the call stub sets up like the interpreter we call the from_interpreted_entry
 383   // so we can go compiled via a i2c. Otherwise initial entry method will always
 384   // run interpreted.
 385   address entry_point = method->from_interpreted_entry();
 386   if (JvmtiExport::can_post_interpreter_events() && thread->is_interp_only_mode()) {
 387     entry_point = method->interpreter_entry();
 388   }
 389 
 390   // Figure out if the result value is an oop or not (Note: This is a different value
 391   // than result_type. result_type will be T_INT of oops. (it is about size)
 392   BasicType result_type = runtime_type_from(result);
 393   bool oop_result_flag = is_reference_type(result->get_type());
 394 
 395   // Find receiver
 396   Handle receiver = (!method->is_static()) ? args->receiver() : Handle();
 397 
 398   // When we reenter Java, we need to reenable the reserved/yellow zone which
 399   // might already be disabled when we are in VM.
 400   if (!thread->stack_guards_enabled()) {
 401     thread->reguard_stack();
 402   }
 403 
 404   // Check that there are shadow pages available before changing thread state
 405   // to Java. Calculate current_stack_pointer here to make sure
 406   // stack_shadow_pages_available() and bang_stack_shadow_pages() use the same sp.
 407   address sp = os::current_stack_pointer();
 408   if (!os::stack_shadow_pages_available(THREAD, method, sp)) {
 409     // Throw stack overflow exception with preinitialized exception.
 410     Exceptions::throw_stack_overflow_exception(THREAD, __FILE__, __LINE__, method);
 411     return;
 412   } else {
 413     // Touch pages checked if the OS needs them to be touched to be mapped.
 414     os::map_stack_shadow_pages(sp);
 415   }
 416 
 417 #if INCLUDE_JVMCI
 418   if (alternative_target != NULL) {
 419     if (alternative_target->is_alive() && !alternative_target->is_unloading()) {
 420       thread->set_jvmci_alternate_call_target(alternative_target->verified_entry_point());
 421       entry_point = method->adapter()->get_i2c_entry();
 422     } else {
 423       THROW(vmSymbols::jdk_vm_ci_code_InvalidInstalledCodeException());
 424     }
 425   }
 426 #endif
 427 
 428   // do call
 429   { JavaCallWrapper link(method, receiver, result, CHECK);
 430     { HandleMark hm(thread);  // HandleMark used by HandleMarkCleaner
 431 
 432       // NOTE: if we move the computation of the result_val_address inside
 433       // the call to call_stub, the optimizer produces wrong code.
 434       intptr_t* result_val_address = (intptr_t*)(result->get_value_addr());
 435       intptr_t* parameter_address = args->parameters();
 436 
 437       StubRoutines::call_stub()(
 438         (address)&link,
 439         // (intptr_t*)&(result->_value), // see NOTE above (compiler problem)
 440         result_val_address,          // see NOTE above (compiler problem)
 441         result_type,
 442         method(),
 443         entry_point,
 444         parameter_address,
 445         args->size_of_parameters(),
 446         CHECK
 447       );
 448 
 449       result = link.result();  // circumvent MS C++ 5.0 compiler bug (result is clobbered across call)
 450       // Preserve oop return value across possible gc points
 451       if (oop_result_flag) {
 452         thread->set_vm_result((oop) result->get_jobject());
 453       }
 454     }
 455   } // Exit JavaCallWrapper (can block - potential return oop must be preserved)
 456 
 457   // Check if a thread stop or suspend should be executed
 458   // The following assert was not realistic.  Thread.stop can set that bit at any moment.
 459   //assert(!thread->has_special_runtime_exit_condition(), "no async. exceptions should be installed");
 460 
 461   // Restore possible oop return
 462   if (oop_result_flag) {
 463     result->set_jobject((jobject)thread->vm_result());
 464     thread->set_vm_result(NULL);
 465   }
 466 }
 467 
 468 
 469 //--------------------------------------------------------------------------------------
 470 // Implementation of JavaCallArguments
 471 
 472 inline bool is_value_state_indirect_oop(uint state) {
 473   assert(state != JavaCallArguments::value_state_oop,
 474          "Checking for handles after removal");
 475   assert(state < JavaCallArguments::value_state_limit,
 476          "Invalid value state %u", state);
 477   return state != JavaCallArguments::value_state_primitive;
 478 }
 479 
 480 inline oop resolve_indirect_oop(intptr_t value, uint state) {
 481   switch (state) {
 482   case JavaCallArguments::value_state_handle:
 483   {
 484     oop* ptr = reinterpret_cast<oop*>(value);
 485     return Handle::raw_resolve(ptr);
 486   }
 487 
 488   case JavaCallArguments::value_state_jobject:
 489   {
 490     jobject obj = reinterpret_cast<jobject>(value);
 491     return JNIHandles::resolve(obj);
 492   }
 493 
 494   default:
 495     ShouldNotReachHere();
 496     return NULL;
 497   }
 498 }
 499 
 500 intptr_t* JavaCallArguments::parameters() {
 501   // First convert all handles to oops
 502   for(int i = 0; i < _size; i++) {
 503     uint state = _value_state[i];
 504     assert(state != value_state_oop, "Multiple handle conversions");
 505     if (is_value_state_indirect_oop(state)) {
 506       oop obj = resolve_indirect_oop(_value[i], state);
 507       _value[i] = cast_from_oop<intptr_t>(obj);
 508       _value_state[i] = value_state_oop;
 509     }
 510   }
 511   // Return argument vector
 512   return _value;
 513 }
 514 
 515 
 516 class SignatureChekker : public SignatureIterator {
 517  private:
 518    int _pos;
 519    BasicType _return_type;
 520    u_char* _value_state;
 521    intptr_t* _value;
 522 
 523  public:
 524   bool _is_return;
 525 
 526   SignatureChekker(Symbol* signature,
 527                    BasicType return_type,
 528                    bool is_static,
 529                    u_char* value_state,
 530                    intptr_t* value) :
 531     SignatureIterator(signature),
 532     _pos(0),
 533     _return_type(return_type),
 534     _value_state(value_state),
 535     _value(value),
 536     _is_return(false)
 537   {
 538     if (!is_static) {
 539       check_value(true); // Receiver must be an oop
 540     }
 541   }
 542 
 543   void check_value(bool type) {
 544     uint state = _value_state[_pos++];
 545     if (type) {
 546       guarantee(is_value_state_indirect_oop(state),
 547                 "signature does not match pushed arguments: %u at %d",
 548                 state, _pos - 1);
 549     } else {
 550       guarantee(state == JavaCallArguments::value_state_primitive,
 551                 "signature does not match pushed arguments: %u at %d",
 552                 state, _pos - 1);
 553     }
 554   }
 555 
 556   void check_doing_return(bool state) { _is_return = state; }
 557 
 558   void check_return_type(BasicType t) {
 559     guarantee(_is_return && t == _return_type, "return type does not match");
 560   }
 561 
 562   void check_int(BasicType t) {
 563     if (_is_return) {
 564       check_return_type(t);
 565       return;
 566     }
 567     check_value(false);
 568   }
 569 
 570   void check_double(BasicType t) { check_long(t); }
 571 
 572   void check_long(BasicType t) {
 573     if (_is_return) {
 574       check_return_type(t);
 575       return;
 576     }
 577 
 578     check_value(false);
 579     check_value(false);
 580   }
 581 
 582   void check_obj(BasicType t) {
 583     if (_is_return) {
 584       check_return_type(t);
 585       return;
 586     }
 587 
 588     intptr_t v = _value[_pos];
 589     if (v != 0) {
 590       // v is a "handle" referring to an oop, cast to integral type.
 591       // There shouldn't be any handles in very low memory.
 592       guarantee((size_t)v >= (size_t)os::vm_page_size(),
 593                 "Bad JNI oop argument %d: " PTR_FORMAT, _pos, v);
 594       // Verify the pointee.
 595       oop vv = resolve_indirect_oop(v, _value_state[_pos]);
 596       guarantee(oopDesc::is_oop_or_null(vv, true),
 597                 "Bad JNI oop argument %d: " PTR_FORMAT " -> " PTR_FORMAT,
 598                 _pos, v, p2i(vv));
 599     }
 600 
 601     check_value(true);          // Verify value state.
 602   }
 603 
 604   void do_bool()                       { check_int(T_BOOLEAN);       }
 605   void do_char()                       { check_int(T_CHAR);          }
 606   void do_float()                      { check_int(T_FLOAT);         }
 607   void do_double()                     { check_double(T_DOUBLE);     }
 608   void do_byte()                       { check_int(T_BYTE);          }
 609   void do_short()                      { check_int(T_SHORT);         }
 610   void do_int()                        { check_int(T_INT);           }
 611   void do_long()                       { check_long(T_LONG);         }
 612   void do_void()                       { check_return_type(T_VOID);  }
 613   void do_object(int begin, int end)   { check_obj(T_OBJECT);        }
 614   void do_array(int begin, int end)    { check_obj(T_OBJECT);        }
 615 };
 616 
 617 
 618 void JavaCallArguments::verify(const methodHandle& method, BasicType return_type) {
 619   guarantee(method->size_of_parameters() == size_of_parameters(), "wrong no. of arguments pushed");
 620 
 621   // Treat T_OBJECT and T_ARRAY as the same
 622   if (is_reference_type(return_type)) return_type = T_OBJECT;
 623 
 624   // Check that oop information is correct
 625   Symbol* signature = method->signature();
 626 
 627   SignatureChekker sc(signature,
 628                       return_type,
 629                       method->is_static(),
 630                       _value_state,
 631                       _value);
 632   sc.iterate_parameters();
 633   sc.check_doing_return(true);
 634   sc.iterate_returntype();
 635 }