1 /*
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   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
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  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
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  24 
  25 #ifndef SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
  26 #define SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
  27 
  28 #include "runtime/handles.inline.hpp"
  29 #include "runtime/mutexLocker.hpp"
  30 #include "runtime/orderAccess.hpp"
  31 #include "runtime/os.hpp"
  32 #include "runtime/safepointMechanism.inline.hpp"
  33 #include "runtime/safepointVerifiers.hpp"
  34 #include "runtime/thread.hpp"
  35 #include "runtime/vmOperations.hpp"
  36 #include "utilities/globalDefinitions.hpp"
  37 #include "utilities/histogram.hpp"
  38 #include "utilities/macros.hpp"
  39 #include "utilities/preserveException.hpp"
  40 
  41 // Wrapper for all entry points to the virtual machine.
  42 
  43 // InterfaceSupport provides functionality used by the VM_LEAF_BASE and
  44 // VM_ENTRY_BASE macros. These macros are used to guard entry points into
  45 // the VM and perform checks upon leave of the VM.
  46 
  47 
  48 class InterfaceSupport: AllStatic {
  49 # ifdef ASSERT
  50  public:
  51   static long _scavenge_alot_counter;
  52   static long _fullgc_alot_counter;
  53   static long _number_of_calls;
  54   static long _fullgc_alot_invocation;
  55 
  56   // Helper methods used to implement +ScavengeALot and +FullGCALot
  57   static void check_gc_alot() { if (ScavengeALot || FullGCALot) gc_alot(); }
  58   static void gc_alot();
  59 
  60   static void walk_stack_from(vframe* start_vf);
  61   static void walk_stack();
  62 
  63   static void zombieAll();
  64   static void deoptimizeAll();
  65   static void stress_derived_pointers();
  66   static void verify_stack();
  67   static void verify_last_frame();
  68 # endif
  69 };
  70 
  71 
  72 // Basic class for all thread transition classes.
  73 
  74 class ThreadStateTransition : public StackObj {
  75  protected:
  76   JavaThread* _thread;
  77  public:
  78   ThreadStateTransition(JavaThread *thread) {
  79     _thread = thread;
  80     assert(thread != NULL && thread->is_Java_thread(), "must be Java thread");
  81   }
  82 
  83   // Change threadstate in a manner, so safepoint can detect changes.
  84   // Time-critical: called on exit from every runtime routine
  85   static inline void transition(JavaThread *thread, JavaThreadState from, JavaThreadState to) {
  86     assert(from != _thread_in_Java, "use transition_from_java");
  87     assert(from != _thread_in_native, "use transition_from_native");
  88     assert((from & 1) == 0 && (to & 1) == 0, "odd numbers are transitions states");
  89     assert(thread->thread_state() == from, "coming from wrong thread state");
  90 
  91     // Check NoSafepointVerifier
  92     // This also clears unhandled oops if CheckUnhandledOops is used.
  93     thread->check_possible_safepoint();
  94 
  95     // Change to transition state and ensure it is seen by the VM thread.
  96     thread->set_thread_state_fence((JavaThreadState)(from + 1));
  97 
  98     SafepointMechanism::block_if_requested(thread);
  99     thread->set_thread_state(to);
 100   }
 101 
 102   // Same as above, but assumes from = _thread_in_Java. This is simpler, since we
 103   // never block on entry to the VM. This will break the code, since e.g. preserve arguments
 104   // have not been setup.
 105   static inline void transition_from_java(JavaThread *thread, JavaThreadState to) {
 106     assert(thread->thread_state() == _thread_in_Java, "coming from wrong thread state: %s", thread->thread_state_name());
 107     thread->set_thread_state(to);
 108   }
 109 
 110   static inline void transition_from_native(JavaThread *thread, JavaThreadState to) {
 111     assert((to & 1) == 0, "odd numbers are transitions states");
 112     assert(thread->thread_state() == _thread_in_native, "coming from wrong thread state: %s", thread->thread_state_name());
 113     // Change to transition state and ensure it is seen by the VM thread.
 114     thread->set_thread_state_fence(_thread_in_native_trans);
 115 
 116     // We never install asynchronous exceptions when coming (back) in
 117     // to the runtime from native code because the runtime is not set
 118     // up to handle exceptions floating around at arbitrary points.
 119     if (SafepointMechanism::should_block(thread) || thread->is_suspend_after_native()) {
 120       JavaThread::check_safepoint_and_suspend_for_native_trans(thread);
 121     }
 122 
 123     thread->set_thread_state(to);
 124   }
 125  protected:
 126    void trans(JavaThreadState from, JavaThreadState to)  { transition(_thread, from, to); }
 127    void trans_from_java(JavaThreadState to)              { transition_from_java(_thread, to); }
 128    void trans_from_native(JavaThreadState to)            { transition_from_native(_thread, to); }
 129 };
 130 
 131 class ThreadInVMForHandshake : public ThreadStateTransition {
 132   const JavaThreadState _original_state;
 133 
 134   void transition_back() {
 135     // This can be invoked from transition states and must return to the original state properly
 136     assert(_thread->thread_state() == _thread_in_vm, "should only call when leaving VM after handshake");
 137     // Change to transition state and ensure it is seen by the VM thread.
 138     _thread->set_thread_state_fence(_thread_in_vm_trans);
 139 
 140     SafepointMechanism::block_if_requested(_thread);
 141 
 142     _thread->set_thread_state(_original_state);
 143 
 144     if (_original_state != _thread_blocked_trans &&  _original_state != _thread_in_vm_trans &&
 145         _thread->has_special_runtime_exit_condition()) {
 146       _thread->handle_special_runtime_exit_condition(
 147           !_thread->is_at_poll_safepoint() && (_original_state != _thread_in_native_trans));
 148     }
 149   }
 150 
 151  public:
 152 
 153   ThreadInVMForHandshake(JavaThread* thread) : ThreadStateTransition(thread),
 154       _original_state(thread->thread_state()) {
 155 
 156     if (thread->has_last_Java_frame()) {
 157       thread->frame_anchor()->make_walkable(thread);
 158     }
 159 
 160     thread->set_thread_state(_thread_in_vm);
 161   }
 162 
 163   ~ThreadInVMForHandshake() {
 164     transition_back();
 165   }
 166 
 167 };
 168 
 169 class ThreadInVMfromJava : public ThreadStateTransition {
 170  public:
 171   ThreadInVMfromJava(JavaThread* thread) : ThreadStateTransition(thread) {
 172     trans_from_java(_thread_in_vm);
 173   }
 174   ~ThreadInVMfromJava()  {
 175     if (_thread->stack_yellow_reserved_zone_disabled()) {
 176       _thread->enable_stack_yellow_reserved_zone();
 177     }
 178     trans(_thread_in_vm, _thread_in_Java);
 179     // Check for pending. async. exceptions or suspends.
 180     if (_thread->has_special_runtime_exit_condition()) _thread->handle_special_runtime_exit_condition();
 181   }
 182 };
 183 
 184 
 185 class ThreadInVMfromUnknown {
 186   JavaThread* _thread;
 187  public:
 188   ThreadInVMfromUnknown() : _thread(NULL) {
 189     Thread* t = Thread::current();
 190     if (t->is_Java_thread()) {
 191       JavaThread* t2 = (JavaThread*) t;
 192       if (t2->thread_state() == _thread_in_native) {
 193         _thread = t2;
 194         ThreadStateTransition::transition_from_native(t2, _thread_in_vm);
 195         // Used to have a HandleMarkCleaner but that is dangerous as
 196         // it could free a handle in our (indirect, nested) caller.
 197         // We expect any handles will be short lived and figure we
 198         // don't need an actual HandleMark.
 199       }
 200     }
 201   }
 202   ~ThreadInVMfromUnknown()  {
 203     if (_thread) {
 204       ThreadStateTransition::transition(_thread, _thread_in_vm, _thread_in_native);
 205     }
 206   }
 207 };
 208 
 209 
 210 class ThreadInVMfromNative : public ThreadStateTransition {
 211  public:
 212   ThreadInVMfromNative(JavaThread* thread) : ThreadStateTransition(thread) {
 213     trans_from_native(_thread_in_vm);
 214   }
 215   ~ThreadInVMfromNative() {
 216     trans(_thread_in_vm, _thread_in_native);
 217   }
 218 };
 219 
 220 
 221 class ThreadToNativeFromVM : public ThreadStateTransition {
 222  public:
 223   ThreadToNativeFromVM(JavaThread *thread) : ThreadStateTransition(thread) {
 224     // We are leaving the VM at this point and going directly to native code.
 225     // Block, if we are in the middle of a safepoint synchronization.
 226     assert(!thread->owns_locks(), "must release all locks when leaving VM");
 227     thread->frame_anchor()->make_walkable(thread);
 228     trans(_thread_in_vm, _thread_in_native);
 229     // Check for pending. async. exceptions or suspends.
 230     if (_thread->has_special_runtime_exit_condition()) _thread->handle_special_runtime_exit_condition(false);
 231   }
 232 
 233   ~ThreadToNativeFromVM() {
 234     trans_from_native(_thread_in_vm);
 235     assert(!_thread->is_pending_jni_exception_check(), "Pending JNI Exception Check");
 236     // We don't need to clear_walkable because it will happen automagically when we return to java
 237   }
 238 };
 239 
 240 
 241 class ThreadBlockInVM : public ThreadStateTransition {
 242  public:
 243   ThreadBlockInVM(JavaThread *thread)
 244   : ThreadStateTransition(thread) {
 245     // Once we are blocked vm expects stack to be walkable
 246     thread->frame_anchor()->make_walkable(thread);
 247     trans(_thread_in_vm, _thread_blocked);
 248   }
 249   ~ThreadBlockInVM() {
 250     trans(_thread_blocked, _thread_in_vm);
 251     OrderAccess::cross_modify_fence();
 252     // We don't need to clear_walkable because it will happen automagically when we return to java
 253   }
 254 };
 255 
 256 // Unlike ThreadBlockInVM, this class is designed to avoid certain deadlock scenarios while making
 257 // transitions inside class Monitor in cases where we need to block for a safepoint or handshake. It
 258 // receives an extra argument compared to ThreadBlockInVM, the address of a pointer to the monitor we
 259 // are trying to acquire. This will be used to access and release the monitor if needed to avoid
 260 // said deadlocks.
 261 // It works like ThreadBlockInVM but differs from it in two ways:
 262 // - When transitioning in (constructor), it checks for safepoints without blocking, i.e., calls
 263 //   back if needed to allow a pending safepoint to continue but does not block in it.
 264 // - When transitioning back (destructor), if there is a pending safepoint or handshake it releases
 265 //   the monitor that is only partially acquired.
 266 class ThreadBlockInVMWithDeadlockCheck : public ThreadStateTransition {
 267  private:
 268   Monitor** _in_flight_monitor_adr;
 269 
 270   void release_monitor() {
 271     assert(_in_flight_monitor_adr != NULL, "_in_flight_monitor_adr should have been set on constructor");
 272     Monitor* in_flight_monitor = *_in_flight_monitor_adr;
 273     if (in_flight_monitor != NULL) {
 274       in_flight_monitor->release_for_safepoint();
 275       *_in_flight_monitor_adr = NULL;
 276     }
 277   }
 278  public:
 279   ThreadBlockInVMWithDeadlockCheck(JavaThread* thread, Monitor** in_flight_monitor_adr)
 280   : ThreadStateTransition(thread), _in_flight_monitor_adr(in_flight_monitor_adr) {
 281     // Once we are blocked vm expects stack to be walkable
 282     thread->frame_anchor()->make_walkable(thread);
 283 
 284     // All unsafe states are treated the same by the VMThread
 285     // so we can skip the _thread_in_vm_trans state here. Since
 286     // we don't read poll, it's enough to order the stores.
 287     OrderAccess::storestore();
 288 
 289     thread->set_thread_state(_thread_blocked);
 290   }
 291   ~ThreadBlockInVMWithDeadlockCheck() {
 292     // Change to transition state and ensure it is seen by the VM thread.
 293     _thread->set_thread_state_fence((JavaThreadState)(_thread_blocked_trans));
 294 
 295     if (SafepointMechanism::should_block(_thread)) {
 296       release_monitor();
 297       SafepointMechanism::block_if_requested(_thread);
 298     }
 299 
 300     _thread->set_thread_state(_thread_in_vm);
 301     OrderAccess::cross_modify_fence();
 302   }
 303 };
 304 
 305 
 306 // This special transition class is only used to prevent asynchronous exceptions
 307 // from being installed on vm exit in situations where we can't tolerate them.
 308 // See bugs: 4324348, 4854693, 4998314, 5040492, 5050705.
 309 class ThreadInVMfromJavaNoAsyncException : public ThreadStateTransition {
 310  public:
 311   ThreadInVMfromJavaNoAsyncException(JavaThread* thread) : ThreadStateTransition(thread) {
 312     trans_from_java(_thread_in_vm);
 313   }
 314   ~ThreadInVMfromJavaNoAsyncException()  {
 315     if (_thread->stack_yellow_reserved_zone_disabled()) {
 316       _thread->enable_stack_yellow_reserved_zone();
 317     }
 318     trans(_thread_in_vm, _thread_in_Java);
 319     // NOTE: We do not check for pending. async. exceptions.
 320     // If we did and moved the pending async exception over into the
 321     // pending exception field, we would need to deopt (currently C2
 322     // only). However, to do so would require that we transition back
 323     // to the _thread_in_vm state. Instead we postpone the handling of
 324     // the async exception.
 325 
 326 
 327     // Check for pending. suspends only.
 328     if (_thread->has_special_runtime_exit_condition())
 329       _thread->handle_special_runtime_exit_condition(false);
 330   }
 331 };
 332 
 333 // Debug class instantiated in JRT_ENTRY macro.
 334 // Can be used to verify properties on enter/exit of the VM.
 335 
 336 #ifdef ASSERT
 337 class VMEntryWrapper {
 338  public:
 339   VMEntryWrapper();
 340   ~VMEntryWrapper();
 341 };
 342 
 343 
 344 class VMNativeEntryWrapper {
 345  public:
 346   VMNativeEntryWrapper();
 347   ~VMNativeEntryWrapper();
 348 };
 349 
 350 class RuntimeHistogramElement : public HistogramElement {
 351   public:
 352    RuntimeHistogramElement(const char* name);
 353 };
 354 #endif // ASSERT
 355 
 356 #ifdef ASSERT
 357 #define TRACE_CALL(result_type, header)                            \
 358   InterfaceSupport::_number_of_calls++;                            \
 359   if (CountRuntimeCalls) {                                         \
 360     static RuntimeHistogramElement* e = new RuntimeHistogramElement(#header); \
 361     if (e != NULL) e->increment_count();                           \
 362   }
 363 #else
 364 #define TRACE_CALL(result_type, header)                            \
 365   /* do nothing */
 366 #endif // ASSERT
 367 
 368 
 369 // LEAF routines do not lock, GC or throw exceptions
 370 
 371 #define VM_LEAF_BASE(result_type, header)                            \
 372   TRACE_CALL(result_type, header)                                    \
 373   debug_only(NoHandleMark __hm;)                                     \
 374   os::verify_stack_alignment();                                      \
 375   /* begin of body */
 376 
 377 #define VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread)         \
 378   TRACE_CALL(result_type, header)                                    \
 379   debug_only(ResetNoHandleMark __rnhm;)                              \
 380   HandleMarkCleaner __hm(thread);                                    \
 381   Thread* THREAD = thread;                                           \
 382   os::verify_stack_alignment();                                      \
 383   /* begin of body */
 384 
 385 
 386 // ENTRY routines may lock, GC and throw exceptions
 387 
 388 #define VM_ENTRY_BASE(result_type, header, thread)                   \
 389   TRACE_CALL(result_type, header)                                    \
 390   HandleMarkCleaner __hm(thread);                                    \
 391   Thread* THREAD = thread;                                           \
 392   os::verify_stack_alignment();                                      \
 393   /* begin of body */
 394 
 395 
 396 // QUICK_ENTRY routines behave like ENTRY but without a handle mark
 397 
 398 #define VM_QUICK_ENTRY_BASE(result_type, header, thread)             \
 399   TRACE_CALL(result_type, header)                                    \
 400   debug_only(NoHandleMark __hm;)                                     \
 401   Thread* THREAD = thread;                                           \
 402   os::verify_stack_alignment();                                      \
 403   /* begin of body */
 404 
 405 
 406 #define JRT_ENTRY(result_type, header)                               \
 407   result_type header {                                               \
 408     ThreadInVMfromJava __tiv(thread);                                \
 409     VM_ENTRY_BASE(result_type, header, thread)                       \
 410     debug_only(VMEntryWrapper __vew;)
 411 
 412 // JRT_LEAF currently can be called from either _thread_in_Java or
 413 // _thread_in_native mode.
 414 //
 415 // JRT_LEAF rules:
 416 // A JRT_LEAF method may not interfere with safepointing by
 417 //   1) acquiring or blocking on a Mutex or JavaLock - checked
 418 //   2) allocating heap memory - checked
 419 //   3) executing a VM operation - checked
 420 //   4) executing a system call (including malloc) that could block or grab a lock
 421 //   5) invoking GC
 422 //   6) reaching a safepoint
 423 //   7) running too long
 424 // Nor may any method it calls.
 425 
 426 #define JRT_LEAF(result_type, header)                                \
 427   result_type header {                                               \
 428   VM_LEAF_BASE(result_type, header)                                  \
 429   debug_only(NoSafepointVerifier __nsv;)
 430 
 431 
 432 #define JRT_ENTRY_NO_ASYNC(result_type, header)                      \
 433   result_type header {                                               \
 434     ThreadInVMfromJavaNoAsyncException __tiv(thread);                \
 435     VM_ENTRY_BASE(result_type, header, thread)                       \
 436     debug_only(VMEntryWrapper __vew;)
 437 
 438 // Same as JRT Entry but allows for return value after the safepoint
 439 // to get back into Java from the VM
 440 #define JRT_BLOCK_ENTRY(result_type, header)                         \
 441   result_type header {                                               \
 442     TRACE_CALL(result_type, header)                                  \
 443     HandleMarkCleaner __hm(thread);
 444 
 445 #define JRT_BLOCK                                                    \
 446     {                                                                \
 447     ThreadInVMfromJava __tiv(thread);                                \
 448     Thread* THREAD = thread;                                         \
 449     debug_only(VMEntryWrapper __vew;)
 450 
 451 #define JRT_BLOCK_NO_ASYNC                                           \
 452     {                                                                \
 453     ThreadInVMfromJavaNoAsyncException __tiv(thread);                \
 454     Thread* THREAD = thread;                                         \
 455     debug_only(VMEntryWrapper __vew;)
 456 
 457 #define JRT_BLOCK_END }
 458 
 459 #define JRT_END }
 460 
 461 // Definitions for JNI
 462 
 463 #define JNI_ENTRY(result_type, header)                               \
 464     JNI_ENTRY_NO_PRESERVE(result_type, header)                       \
 465     WeakPreserveExceptionMark __wem(thread);
 466 
 467 #define JNI_ENTRY_NO_PRESERVE(result_type, header)                   \
 468 extern "C" {                                                         \
 469   result_type JNICALL header {                                       \
 470     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
 471     assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
 472     ThreadInVMfromNative __tiv(thread);                              \
 473     debug_only(VMNativeEntryWrapper __vew;)                          \
 474     VM_ENTRY_BASE(result_type, header, thread)
 475 
 476 
 477 // Ensure that the VMNativeEntryWrapper constructor, which can cause
 478 // a GC, is called outside the NoHandleMark (set via VM_QUICK_ENTRY_BASE).
 479 #define JNI_QUICK_ENTRY(result_type, header)                         \
 480 extern "C" {                                                         \
 481   result_type JNICALL header {                                       \
 482     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
 483     assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
 484     ThreadInVMfromNative __tiv(thread);                              \
 485     debug_only(VMNativeEntryWrapper __vew;)                          \
 486     VM_QUICK_ENTRY_BASE(result_type, header, thread)
 487 
 488 
 489 #define JNI_LEAF(result_type, header)                                \
 490 extern "C" {                                                         \
 491   result_type JNICALL header {                                       \
 492     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
 493     assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
 494     VM_LEAF_BASE(result_type, header)
 495 
 496 
 497 // Close the routine and the extern "C"
 498 #define JNI_END } }
 499 
 500 
 501 
 502 // Definitions for JVM
 503 
 504 #define JVM_ENTRY(result_type, header)                               \
 505 extern "C" {                                                         \
 506   result_type JNICALL header {                                       \
 507     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
 508     ThreadInVMfromNative __tiv(thread);                              \
 509     debug_only(VMNativeEntryWrapper __vew;)                          \
 510     VM_ENTRY_BASE(result_type, header, thread)
 511 
 512 
 513 #define JVM_ENTRY_NO_ENV(result_type, header)                        \
 514 extern "C" {                                                         \
 515   result_type JNICALL header {                                       \
 516     JavaThread* thread = JavaThread::current();                      \
 517     ThreadInVMfromNative __tiv(thread);                              \
 518     debug_only(VMNativeEntryWrapper __vew;)                          \
 519     VM_ENTRY_BASE(result_type, header, thread)
 520 
 521 
 522 #define JVM_QUICK_ENTRY(result_type, header)                         \
 523 extern "C" {                                                         \
 524   result_type JNICALL header {                                       \
 525     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
 526     ThreadInVMfromNative __tiv(thread);                              \
 527     debug_only(VMNativeEntryWrapper __vew;)                          \
 528     VM_QUICK_ENTRY_BASE(result_type, header, thread)
 529 
 530 
 531 #define JVM_LEAF(result_type, header)                                \
 532 extern "C" {                                                         \
 533   result_type JNICALL header {                                       \
 534     VM_Exit::block_if_vm_exited();                                   \
 535     VM_LEAF_BASE(result_type, header)
 536 
 537 
 538 #define JVM_ENTRY_FROM_LEAF(env, result_type, header)                \
 539   { {                                                                \
 540     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
 541     ThreadInVMfromNative __tiv(thread);                              \
 542     debug_only(VMNativeEntryWrapper __vew;)                          \
 543     VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread)
 544 
 545 
 546 #define JVM_END } }
 547 
 548 #endif // SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP