1 /*
   2  * Copyright (c) 1997, 2018, 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 "runtime/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 #if INCLUDE_JVMCI
  48 #include "jvmci/jvmciJavaClasses.hpp"
  49 #include "jvmci/jvmciRuntime.hpp"
  50 #endif
  51 
  52 // -----------------------------------------------------
  53 // Implementation of JavaCallWrapper
  54 
  55 JavaCallWrapper::JavaCallWrapper(const methodHandle& callee_method, Handle receiver, JavaValue* result, TRAPS) {
  56   JavaThread* thread = (JavaThread *)THREAD;
  57   bool clear_pending_exception = true;
  58 
  59   guarantee(thread->is_Java_thread(), "crucial check - the VM thread cannot and must not escape to Java code");
  60   assert(!thread->owns_locks(), "must release all locks when leaving VM");
  61   guarantee(thread->can_call_java(), "cannot make java calls from the native compiler");
  62   _result   = result;
  63 
  64   // Allocate handle block for Java code. This must be done before we change thread_state to _thread_in_Java_or_stub,
  65   // since it can potentially block.
  66   JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(thread);
  67 
  68   // After this, we are official in JavaCode. This needs to be done before we change any of the thread local
  69   // info, since we cannot find oops before the new information is set up completely.
  70   ThreadStateTransition::transition(thread, _thread_in_vm, _thread_in_Java);
  71 
  72   // Make sure that we handle asynchronous stops and suspends _before_ we clear all thread state
  73   // in JavaCallWrapper::JavaCallWrapper(). This way, we can decide if we need to do any pd actions
  74   // to prepare for stop/suspend (flush register windows on sparcs, cache sp, or other state).
  75   if (thread->has_special_runtime_exit_condition()) {
  76     thread->handle_special_runtime_exit_condition();
  77     if (HAS_PENDING_EXCEPTION) {
  78       clear_pending_exception = false;
  79     }
  80   }
  81 
  82 
  83   // Make sure to set the oop's after the thread transition - since we can block there. No one is GC'ing
  84   // the JavaCallWrapper before the entry frame is on the stack.
  85   _callee_method = callee_method();
  86   _receiver = receiver();
  87 
  88 #ifdef CHECK_UNHANDLED_OOPS
  89   THREAD->allow_unhandled_oop(&_receiver);
  90 #endif // CHECK_UNHANDLED_OOPS
  91 
  92   _thread       = (JavaThread *)thread;
  93   _handles      = _thread->active_handles();    // save previous handle block & Java frame linkage
  94 
  95   // For the profiler, the last_Java_frame information in thread must always be in
  96   // legal state. We have no last Java frame if last_Java_sp == NULL so
  97   // the valid transition is to clear _last_Java_sp and then reset the rest of
  98   // the (platform specific) state.
  99 
 100   _anchor.copy(_thread->frame_anchor());
 101   _thread->frame_anchor()->clear();
 102 
 103   debug_only(_thread->inc_java_call_counter());
 104   _thread->set_active_handles(new_handles);     // install new handle block and reset Java frame linkage
 105 
 106   assert (_thread->thread_state() != _thread_in_native, "cannot set native pc to NULL");
 107 
 108   // clear any pending exception in thread (native calls start with no exception pending)
 109   if(clear_pending_exception) {
 110     _thread->clear_pending_exception();
 111   }
 112 
 113   if (_anchor.last_Java_sp() == NULL) {
 114     _thread->record_base_of_stack_pointer();
 115   }
 116 }
 117 
 118 
 119 JavaCallWrapper::~JavaCallWrapper() {
 120   assert(_thread == JavaThread::current(), "must still be the same thread");
 121 
 122   // restore previous handle block & Java frame linkage
 123   JNIHandleBlock *_old_handles = _thread->active_handles();
 124   _thread->set_active_handles(_handles);
 125 
 126   _thread->frame_anchor()->zap();
 127 
 128   debug_only(_thread->dec_java_call_counter());
 129 
 130   if (_anchor.last_Java_sp() == NULL) {
 131     _thread->set_base_of_stack_pointer(NULL);
 132   }
 133 
 134 
 135   // Old thread-local info. has been restored. We are not back in the VM.
 136   ThreadStateTransition::transition_from_java(_thread, _thread_in_vm);
 137 
 138   // State has been restored now make the anchor frame visible for the profiler.
 139   // Do this after the transition because this allows us to put an assert
 140   // the Java->vm transition which checks to see that stack is not walkable
 141   // on sparc/ia64 which will catch violations of the reseting of last_Java_frame
 142   // invariants (i.e. _flags always cleared on return to Java)
 143 
 144   _thread->frame_anchor()->copy(&_anchor);
 145 
 146   // Release handles after we are marked as being inside the VM again, since this
 147   // operation might block
 148   JNIHandleBlock::release_block(_old_handles, _thread);
 149 }
 150 
 151 
 152 void JavaCallWrapper::oops_do(OopClosure* f) {
 153   f->do_oop((oop*)&_receiver);
 154   handles()->oops_do(f);
 155 }
 156 
 157 
 158 // Helper methods
 159 static BasicType runtime_type_from(JavaValue* result) {
 160   switch (result->get_type()) {
 161     case T_BOOLEAN: // fall through
 162     case T_CHAR   : // fall through
 163     case T_SHORT  : // fall through
 164     case T_INT    : // fall through
 165 #ifndef _LP64
 166     case T_OBJECT : // fall through
 167     case T_ARRAY  : // fall through
 168 #endif
 169     case T_BYTE   : // fall through
 170     case T_VOID   : return T_INT;
 171     case T_LONG   : return T_LONG;
 172     case T_FLOAT  : return T_FLOAT;
 173     case T_DOUBLE : return T_DOUBLE;
 174 #ifdef _LP64
 175     case T_ARRAY  : // fall through
 176     case T_OBJECT:  return T_OBJECT;
 177 #endif
 178     default:
 179       ShouldNotReachHere();
 180       return T_ILLEGAL;
 181   }
 182 }
 183 
 184 // ============ Virtual calls ============
 185 
 186 void JavaCalls::call_virtual(JavaValue* result, Klass* spec_klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS) {
 187   CallInfo callinfo;
 188   Handle receiver = args->receiver();
 189   Klass* recvrKlass = receiver.is_null() ? (Klass*)NULL : receiver->klass();
 190   LinkInfo link_info(spec_klass, name, signature);
 191   LinkResolver::resolve_virtual_call(
 192           callinfo, receiver, recvrKlass, link_info, true, CHECK);
 193   methodHandle method = callinfo.selected_method();
 194   assert(method.not_null(), "should have thrown exception");
 195 
 196   // Invoke the method
 197   JavaCalls::call(result, method, args, CHECK);
 198 }
 199 
 200 
 201 void JavaCalls::call_virtual(JavaValue* result, Handle receiver, Klass* spec_klass, Symbol* name, Symbol* signature, TRAPS) {
 202   JavaCallArguments args(receiver);
 203   call_virtual(result, spec_klass, name, signature, &args, CHECK);
 204 }
 205 
 206 
 207 void JavaCalls::call_virtual(JavaValue* result, Handle receiver, Klass* spec_klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS) {
 208   JavaCallArguments args(receiver);
 209   args.push_oop(arg1);
 210   call_virtual(result, spec_klass, name, signature, &args, CHECK);
 211 }
 212 
 213 
 214 
 215 void JavaCalls::call_virtual(JavaValue* result, Handle receiver, Klass* spec_klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS) {
 216   JavaCallArguments args(receiver);
 217   args.push_oop(arg1);
 218   args.push_oop(arg2);
 219   call_virtual(result, spec_klass, name, signature, &args, CHECK);
 220 }
 221 
 222 
 223 // ============ Special calls ============
 224 
 225 void JavaCalls::call_special(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS) {
 226   CallInfo callinfo;
 227   LinkInfo link_info(klass, name, signature);
 228   LinkResolver::resolve_special_call(callinfo, args->receiver(), link_info, CHECK);
 229   methodHandle method = callinfo.selected_method();
 230   assert(method.not_null(), "should have thrown exception");
 231 
 232   // Invoke the method
 233   JavaCalls::call(result, method, args, CHECK);
 234 }
 235 
 236 
 237 void JavaCalls::call_special(JavaValue* result, Handle receiver, Klass* klass, Symbol* name, Symbol* signature, TRAPS) {
 238   JavaCallArguments args(receiver);
 239   call_special(result, klass, name, signature, &args, CHECK);
 240 }
 241 
 242 
 243 void JavaCalls::call_special(JavaValue* result, Handle receiver, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS) {
 244   JavaCallArguments args(receiver);
 245   args.push_oop(arg1);
 246   call_special(result, klass, name, signature, &args, CHECK);
 247 }
 248 
 249 
 250 void JavaCalls::call_special(JavaValue* result, Handle receiver, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS) {
 251   JavaCallArguments args(receiver);
 252   args.push_oop(arg1);
 253   args.push_oop(arg2);
 254   call_special(result, klass, name, signature, &args, CHECK);
 255 }
 256 
 257 
 258 // ============ Static calls ============
 259 
 260 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS) {
 261   CallInfo callinfo;
 262   LinkInfo link_info(klass, name, signature);
 263   LinkResolver::resolve_static_call(callinfo, link_info, true, CHECK);
 264   methodHandle method = callinfo.selected_method();
 265   assert(method.not_null(), "should have thrown exception");
 266 
 267   // Invoke the method
 268   JavaCalls::call(result, method, args, CHECK);
 269 }
 270 
 271 
 272 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, TRAPS) {
 273   JavaCallArguments args;
 274   call_static(result, klass, name, signature, &args, CHECK);
 275 }
 276 
 277 
 278 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS) {
 279   JavaCallArguments args(arg1);
 280   call_static(result, klass, name, signature, &args, CHECK);
 281 }
 282 
 283 
 284 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS) {
 285   JavaCallArguments args;
 286   args.push_oop(arg1);
 287   args.push_oop(arg2);
 288   call_static(result, klass, name, signature, &args, CHECK);
 289 }
 290 
 291 
 292 void JavaCalls::call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, Handle arg3, TRAPS) {
 293   JavaCallArguments args;
 294   args.push_oop(arg1);
 295   args.push_oop(arg2);
 296   args.push_oop(arg3);
 297   call_static(result, klass, name, signature, &args, CHECK);
 298 }
 299 
 300 Handle JavaCalls::new_instance(InstanceKlass* klass, Symbol* constructor_signature, JavaCallArguments* args, TRAPS) {
 301   klass->initialize(CHECK_NH); // Quick no-op if already initialized.
 302   Handle obj = klass->allocate_instance_handle(CHECK_NH);
 303   JavaValue void_result(T_VOID);
 304   args->set_receiver(obj);
 305   JavaCalls::call_special(&void_result, klass,
 306                           vmSymbols::object_initializer_name(),
 307                           constructor_signature, args, CHECK_NH);
 308   return obj;
 309 }
 310 
 311 Handle JavaCalls::new_instance(InstanceKlass* klass, Symbol* constructor_signature, TRAPS) {
 312   JavaCallArguments args;
 313   return JavaCalls::new_instance(klass, constructor_signature, &args, CHECK_NH);
 314 }
 315 
 316 Handle JavaCalls::new_instance(InstanceKlass* klass, Symbol* constructor_signature, Handle arg1, TRAPS) {
 317   JavaCallArguments args;
 318   args.push_oop(arg1);
 319   return JavaCalls::new_instance(klass, constructor_signature, &args, CHECK_NH);
 320 }
 321 
 322 Handle JavaCalls::new_instance(InstanceKlass* klass, Symbol* constructor_signature, Handle arg1, Handle arg2, TRAPS) {
 323   JavaCallArguments args;
 324   args.push_oop(arg1);
 325   args.push_oop(arg2);
 326   return JavaCalls::new_instance(klass, constructor_signature, &args, CHECK_NH);
 327 }
 328 
 329 // -------------------------------------------------
 330 // Implementation of JavaCalls (low level)
 331 
 332 
 333 void JavaCalls::call(JavaValue* result, const methodHandle& method, JavaCallArguments* args, TRAPS) {
 334   // Check if we need to wrap a potential OS exception handler around thread
 335   // This is used for e.g. Win32 structured exception handlers
 336   assert(THREAD->is_Java_thread(), "only JavaThreads can make JavaCalls");
 337   // Need to wrap each and every time, since there might be native code down the
 338   // stack that has installed its own exception handlers
 339   os::os_exception_wrapper(call_helper, result, method, args, THREAD);
 340 }
 341 
 342 void JavaCalls::call_helper(JavaValue* result, const methodHandle& method, JavaCallArguments* args, TRAPS) {
 343 
 344   JavaThread* thread = (JavaThread*)THREAD;
 345   assert(thread->is_Java_thread(), "must be called by a java thread");
 346   assert(method.not_null(), "must have a method to call");
 347   assert(!SafepointSynchronize::is_at_safepoint(), "call to Java code during VM operation");
 348   assert(!thread->handle_area()->no_handle_mark_active(), "cannot call out to Java here");
 349 
 350 
 351   CHECK_UNHANDLED_OOPS_ONLY(thread->clear_unhandled_oops();)
 352 
 353 #if INCLUDE_JVMCI
 354   // Gets the nmethod (if any) that should be called instead of normal target
 355   nmethod* alternative_target = args->alternative_target();
 356   if (alternative_target == NULL) {
 357 #endif
 358 // Verify the arguments
 359 
 360   if (CheckJNICalls)  {
 361     args->verify(method, result->get_type());
 362   }
 363   else debug_only(args->verify(method, result->get_type()));
 364 #if INCLUDE_JVMCI
 365   }
 366 #else
 367 
 368   // Ignore call if method is empty
 369   if (method->is_empty_method()) {
 370     assert(result->get_type() == T_VOID, "an empty method must return a void value");
 371     return;
 372   }
 373 #endif
 374 
 375 #ifdef ASSERT
 376   { InstanceKlass* holder = method->method_holder();
 377     // A klass might not be initialized since JavaCall's might be used during the executing of
 378     // the <clinit>. For example, a Thread.start might start executing on an object that is
 379     // not fully initialized! (bad Java programming style)
 380     assert(holder->is_linked(), "rewriting must have taken place");
 381   }
 382 #endif
 383 
 384   CompilationPolicy::compile_if_required(method, CHECK);
 385 
 386   // Since the call stub sets up like the interpreter we call the from_interpreted_entry
 387   // so we can go compiled via a i2c. Otherwise initial entry method will always
 388   // run interpreted.
 389   address entry_point = method->from_interpreted_entry();
 390   if (JvmtiExport::can_post_interpreter_events() && thread->is_interp_only_mode()) {
 391     entry_point = method->interpreter_entry();
 392   }
 393 
 394   // Figure out if the result value is an oop or not (Note: This is a different value
 395   // than result_type. result_type will be T_INT of oops. (it is about size)
 396   BasicType result_type = runtime_type_from(result);
 397   bool oop_result_flag = (result->get_type() == T_OBJECT || result->get_type() == T_ARRAY);
 398 
 399   // NOTE: if we move the computation of the result_val_address inside
 400   // the call to call_stub, the optimizer produces wrong code.
 401   intptr_t* result_val_address = (intptr_t*)(result->get_value_addr());
 402 
 403   // Find receiver
 404   Handle receiver = (!method->is_static()) ? args->receiver() : Handle();
 405 
 406   // When we reenter Java, we need to reenable the reserved/yellow zone which
 407   // might already be disabled when we are in VM.
 408   if (!thread->stack_guards_enabled()) {
 409     thread->reguard_stack();
 410   }
 411 
 412   // Check that there are shadow pages available before changing thread state
 413   // to Java. Calculate current_stack_pointer here to make sure
 414   // stack_shadow_pages_available() and bang_stack_shadow_pages() use the same sp.
 415   address sp = os::current_stack_pointer();
 416   if (!os::stack_shadow_pages_available(THREAD, method, sp)) {
 417     // Throw stack overflow exception with preinitialized exception.
 418     Exceptions::throw_stack_overflow_exception(THREAD, __FILE__, __LINE__, method);
 419     return;
 420   } else {
 421     // Touch pages checked if the OS needs them to be touched to be mapped.
 422     os::map_stack_shadow_pages(sp);
 423   }
 424 
 425 #if INCLUDE_JVMCI
 426   if (alternative_target != NULL) {
 427     if (alternative_target->is_alive()) {
 428       thread->set_jvmci_alternate_call_target(alternative_target->verified_entry_point());
 429       entry_point = method->adapter()->get_i2c_entry();
 430     } else {
 431       THROW(vmSymbols::jdk_vm_ci_code_InvalidInstalledCodeException());
 432     }
 433   }
 434 #endif
 435 
 436   // do call
 437   { JavaCallWrapper link(method, receiver, result, CHECK);
 438     { HandleMark hm(thread);  // HandleMark used by HandleMarkCleaner
 439 
 440       StubRoutines::call_stub()(
 441         (address)&link,
 442         // (intptr_t*)&(result->_value), // see NOTE above (compiler problem)
 443         result_val_address,          // see NOTE above (compiler problem)
 444         result_type,
 445         method(),
 446         entry_point,
 447         args->parameters(),
 448         args->size_of_parameters(),
 449         CHECK
 450       );
 451 
 452       result = link.result();  // circumvent MS C++ 5.0 compiler bug (result is clobbered across call)
 453       // Preserve oop return value across possible gc points
 454       if (oop_result_flag) {
 455         thread->set_vm_result((oop) result->get_jobject());
 456       }
 457     }
 458   } // Exit JavaCallWrapper (can block - potential return oop must be preserved)
 459 
 460   // Check if a thread stop or suspend should be executed
 461   // The following assert was not realistic.  Thread.stop can set that bit at any moment.
 462   //assert(!thread->has_special_runtime_exit_condition(), "no async. exceptions should be installed");
 463 
 464   // Restore possible oop return
 465   if (oop_result_flag) {
 466     result->set_jobject((jobject)thread->vm_result());
 467     thread->set_vm_result(NULL);
 468   }
 469 }
 470 
 471 
 472 //--------------------------------------------------------------------------------------
 473 // Implementation of JavaCallArguments
 474 
 475 inline bool is_value_state_indirect_oop(uint state) {
 476   assert(state != JavaCallArguments::value_state_oop,
 477          "Checking for handles after removal");
 478   assert(state < JavaCallArguments::value_state_limit,
 479          "Invalid value state %u", state);
 480   return state != JavaCallArguments::value_state_primitive;
 481 }
 482 
 483 inline oop resolve_indirect_oop(intptr_t value, uint state) {
 484   switch (state) {
 485   case JavaCallArguments::value_state_handle:
 486   {
 487     oop* ptr = reinterpret_cast<oop*>(value);
 488     return Handle::raw_resolve(ptr);
 489   }
 490 
 491   case JavaCallArguments::value_state_jobject:
 492   {
 493     jobject obj = reinterpret_cast<jobject>(value);
 494     return JNIHandles::resolve(obj);
 495   }
 496 
 497   default:
 498     ShouldNotReachHere();
 499     return NULL;
 500   }
 501 }
 502 
 503 intptr_t* JavaCallArguments::parameters() {
 504   // First convert all handles to oops
 505   for(int i = 0; i < _size; i++) {
 506     uint state = _value_state[i];
 507     assert(state != value_state_oop, "Multiple handle conversions");
 508     if (is_value_state_indirect_oop(state)) {
 509       oop obj = resolve_indirect_oop(_value[i], state);
 510       _value[i] = cast_from_oop<intptr_t>(obj);
 511       _value_state[i] = value_state_oop;
 512     }
 513   }
 514   // Return argument vector
 515   return _value;
 516 }
 517 
 518 
 519 class SignatureChekker : public SignatureIterator {
 520  private:
 521    int _pos;
 522    BasicType _return_type;
 523    u_char* _value_state;
 524    intptr_t* _value;
 525 
 526  public:
 527   bool _is_return;
 528 
 529   SignatureChekker(Symbol* signature,
 530                    BasicType return_type,
 531                    bool is_static,
 532                    u_char* value_state,
 533                    intptr_t* value) :
 534     SignatureIterator(signature),
 535     _pos(0),
 536     _return_type(return_type),
 537     _value_state(value_state),
 538     _value(value),
 539     _is_return(false)
 540   {
 541     if (!is_static) {
 542       check_value(true); // Receiver must be an oop
 543     }
 544   }
 545 
 546   void check_value(bool type) {
 547     uint state = _value_state[_pos++];
 548     if (type) {
 549       guarantee(is_value_state_indirect_oop(state),
 550                 "signature does not match pushed arguments: %u at %d",
 551                 state, _pos - 1);
 552     } else {
 553       guarantee(state == JavaCallArguments::value_state_primitive,
 554                 "signature does not match pushed arguments: %u at %d",
 555                 state, _pos - 1);
 556     }
 557   }
 558 
 559   void check_doing_return(bool state) { _is_return = state; }
 560 
 561   void check_return_type(BasicType t) {
 562     guarantee(_is_return && t == _return_type, "return type does not match");
 563   }
 564 
 565   void check_int(BasicType t) {
 566     if (_is_return) {
 567       check_return_type(t);
 568       return;
 569     }
 570     check_value(false);
 571   }
 572 
 573   void check_double(BasicType t) { check_long(t); }
 574 
 575   void check_long(BasicType t) {
 576     if (_is_return) {
 577       check_return_type(t);
 578       return;
 579     }
 580 
 581     check_value(false);
 582     check_value(false);
 583   }
 584 
 585   void check_obj(BasicType t) {
 586     if (_is_return) {
 587       check_return_type(t);
 588       return;
 589     }
 590 
 591     intptr_t v = _value[_pos];
 592     if (v != 0) {
 593       // v is a "handle" referring to an oop, cast to integral type.
 594       // There shouldn't be any handles in very low memory.
 595       guarantee((size_t)v >= (size_t)os::vm_page_size(),
 596                 "Bad JNI oop argument %d: " PTR_FORMAT, _pos, v);
 597       // Verify the pointee.
 598       oop vv = resolve_indirect_oop(v, _value_state[_pos]);
 599       guarantee(oopDesc::is_oop_or_null(vv, true),
 600                 "Bad JNI oop argument %d: " PTR_FORMAT " -> " PTR_FORMAT,
 601                 _pos, v, p2i(vv));
 602     }
 603 
 604     check_value(true);          // Verify value state.
 605   }
 606 
 607   void do_bool()                       { check_int(T_BOOLEAN);       }
 608   void do_char()                       { check_int(T_CHAR);          }
 609   void do_float()                      { check_int(T_FLOAT);         }
 610   void do_double()                     { check_double(T_DOUBLE);     }
 611   void do_byte()                       { check_int(T_BYTE);          }
 612   void do_short()                      { check_int(T_SHORT);         }
 613   void do_int()                        { check_int(T_INT);           }
 614   void do_long()                       { check_long(T_LONG);         }
 615   void do_void()                       { check_return_type(T_VOID);  }
 616   void do_object(int begin, int end)   { check_obj(T_OBJECT);        }
 617   void do_array(int begin, int end)    { check_obj(T_OBJECT);        }
 618 };
 619 
 620 
 621 void JavaCallArguments::verify(const methodHandle& method, BasicType return_type) {
 622   guarantee(method->size_of_parameters() == size_of_parameters(), "wrong no. of arguments pushed");
 623 
 624   // Treat T_OBJECT and T_ARRAY as the same
 625   if (return_type == T_ARRAY) return_type = T_OBJECT;
 626 
 627   // Check that oop information is correct
 628   Symbol* signature = method->signature();
 629 
 630   SignatureChekker sc(signature,
 631                       return_type,
 632                       method->is_static(),
 633                       _value_state,
 634                       _value);
 635   sc.iterate_parameters();
 636   sc.check_doing_return(true);
 637   sc.iterate_returntype();
 638 }