1 /*
   2  * Copyright (c) 2000, 2017, 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/classFileStream.hpp"
  27 #include "classfile/vmSymbols.hpp"
  28 #include "memory/allocation.inline.hpp"
  29 #include "memory/resourceArea.hpp"
  30 #include "oops/objArrayOop.inline.hpp"
  31 #include "oops/oop.inline.hpp"
  32 #include "prims/jni.h"
  33 #include "prims/jvm.h"
  34 #include "prims/unsafe.hpp"
  35 #include "runtime/atomic.hpp"
  36 #include "runtime/globals.hpp"
  37 #include "runtime/interfaceSupport.hpp"
  38 #include "runtime/orderAccess.inline.hpp"
  39 #include "runtime/reflection.hpp"
  40 #include "runtime/vm_version.hpp"
  41 #include "services/threadService.hpp"
  42 #include "trace/tracing.hpp"
  43 #include "utilities/copy.hpp"
  44 #include "utilities/dtrace.hpp"
  45 #include "utilities/macros.hpp"
  46 #if INCLUDE_ALL_GCS
  47 #include "gc/g1/g1SATBCardTableModRefBS.hpp"
  48 #endif // INCLUDE_ALL_GCS
  49 
  50 /**
  51  * Implementation of the jdk.internal.misc.Unsafe class
  52  */
  53 
  54 
  55 #define MAX_OBJECT_SIZE \
  56   ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
  57     + ((julong)max_jint * sizeof(double)) )
  58 
  59 
  60 #define UNSAFE_ENTRY(result_type, header) \
  61   JVM_ENTRY(static result_type, header)
  62 
  63 #define UNSAFE_LEAF(result_type, header) \
  64   JVM_LEAF(static result_type, header)
  65 
  66 #define UNSAFE_END JVM_END
  67 
  68 
  69 static inline void* addr_from_java(jlong addr) {
  70   // This assert fails in a variety of ways on 32-bit systems.
  71   // It is impossible to predict whether native code that converts
  72   // pointers to longs will sign-extend or zero-extend the addresses.
  73   //assert(addr == (uintptr_t)addr, "must not be odd high bits");
  74   return (void*)(uintptr_t)addr;
  75 }
  76 
  77 static inline jlong addr_to_java(void* p) {
  78   assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
  79   return (uintptr_t)p;
  80 }
  81 
  82 
  83 // Note: The VM's obj_field and related accessors use byte-scaled
  84 // ("unscaled") offsets, just as the unsafe methods do.
  85 
  86 // However, the method Unsafe.fieldOffset explicitly declines to
  87 // guarantee this.  The field offset values manipulated by the Java user
  88 // through the Unsafe API are opaque cookies that just happen to be byte
  89 // offsets.  We represent this state of affairs by passing the cookies
  90 // through conversion functions when going between the VM and the Unsafe API.
  91 // The conversion functions just happen to be no-ops at present.
  92 
  93 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
  94   return field_offset;
  95 }
  96 
  97 static inline jlong field_offset_from_byte_offset(jlong byte_offset) {
  98   return byte_offset;
  99 }
 100 
 101 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
 102   jlong byte_offset = field_offset_to_byte_offset(field_offset);
 103 
 104 #ifdef ASSERT
 105   if (p != NULL) {
 106     assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
 107     if (byte_offset == (jint)byte_offset) {
 108       void* ptr_plus_disp = (address)p + byte_offset;
 109       assert((void*)p->obj_field_addr<oop>((jint)byte_offset) == ptr_plus_disp,
 110              "raw [ptr+disp] must be consistent with oop::field_base");
 111     }
 112     jlong p_size = HeapWordSize * (jlong)(p->size());
 113     assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, byte_offset, p_size);
 114   }
 115 #endif
 116 
 117   if (sizeof(char*) == sizeof(jint)) {   // (this constant folds!)
 118     return (address)p + (jint) byte_offset;
 119   } else {
 120     return (address)p +        byte_offset;
 121   }
 122 }
 123 
 124 // Externally callable versions:
 125 // (Use these in compiler intrinsics which emulate unsafe primitives.)
 126 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
 127   return field_offset;
 128 }
 129 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
 130   return byte_offset;
 131 }
 132 
 133 
 134 ///// Data read/writes on the Java heap and in native (off-heap) memory
 135 
 136 /**
 137  * Helper class for accessing memory.
 138  *
 139  * Normalizes values and wraps accesses in
 140  * JavaThread::doing_unsafe_access() if needed.
 141  */
 142 class MemoryAccess : StackObj {
 143   JavaThread* _thread;
 144   jobject _obj;
 145   jlong _offset;
 146 
 147   // Resolves and returns the address of the memory access
 148   void* addr() {
 149     return index_oop_from_field_offset_long(JNIHandles::resolve(_obj), _offset);
 150   }
 151 
 152   template <typename T>
 153   T normalize_for_write(T x) {
 154     return x;
 155   }
 156 
 157   jboolean normalize_for_write(jboolean x) {
 158     return x & 1;
 159   }
 160 
 161   template <typename T>
 162   T normalize_for_read(T x) {
 163     return x;
 164   }
 165 
 166   jboolean normalize_for_read(jboolean x) {
 167     return x != 0;
 168   }
 169 
 170   /**
 171    * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
 172    */
 173   class GuardUnsafeAccess {
 174     JavaThread* _thread;
 175     bool _active;
 176 
 177   public:
 178     GuardUnsafeAccess(JavaThread* thread, jobject _obj) : _thread(thread) {
 179       if (JNIHandles::resolve(_obj) == NULL) {
 180         // native/off-heap access which may raise SIGBUS if accessing
 181         // memory mapped file data in a region of the file which has
 182         // been truncated and is now invalid
 183         _thread->set_doing_unsafe_access(true);
 184         _active = true;
 185       } else {
 186         _active = false;
 187       }
 188     }
 189 
 190     ~GuardUnsafeAccess() {
 191       if (_active) {
 192         _thread->set_doing_unsafe_access(false);
 193       }
 194     }
 195   };
 196 
 197 public:
 198   MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
 199     : _thread(thread), _obj(obj), _offset(offset) {
 200   }
 201 
 202   template <typename T>
 203   T get() {
 204     GuardUnsafeAccess guard(_thread, _obj);
 205 
 206     T* p = (T*)addr();
 207 
 208     T x = normalize_for_read(*p);
 209 
 210     return x;
 211   }
 212 
 213   template <typename T>
 214   void put(T x) {
 215     GuardUnsafeAccess guard(_thread, _obj);
 216 
 217     T* p = (T*)addr();
 218 
 219     *p = normalize_for_write(x);
 220   }
 221 
 222 
 223   template <typename T>
 224   T get_volatile() {
 225     GuardUnsafeAccess guard(_thread, _obj);
 226 
 227     T* p = (T*)addr();
 228 
 229     if (support_IRIW_for_not_multiple_copy_atomic_cpu) {
 230       OrderAccess::fence();
 231     }
 232 
 233     T x = OrderAccess::load_acquire((volatile T*)p);
 234 
 235     return normalize_for_read(x);
 236   }
 237 
 238   template <typename T>
 239   void put_volatile(T x) {
 240     GuardUnsafeAccess guard(_thread, _obj);
 241 
 242     T* p = (T*)addr();
 243 
 244     OrderAccess::release_store_fence((volatile T*)p, normalize_for_write(x));
 245   }
 246 
 247 
 248 #ifndef SUPPORTS_NATIVE_CX8
 249   jlong get_jlong_locked() {
 250     GuardUnsafeAccess guard(_thread, _obj);
 251 
 252     MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
 253 
 254     jlong* p = (jlong*)addr();
 255 
 256     jlong x = Atomic::load(p);
 257 
 258     return x;
 259   }
 260 
 261   void put_jlong_locked(jlong x) {
 262     GuardUnsafeAccess guard(_thread, _obj);
 263 
 264     MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
 265 
 266     jlong* p = (jlong*)addr();
 267 
 268     Atomic::store(normalize_for_write(x),  p);
 269   }
 270 #endif
 271 };
 272 
 273 // Get/PutObject must be special-cased, since it works with handles.
 274 
 275 // We could be accessing the referent field in a reference
 276 // object. If G1 is enabled then we need to register non-null
 277 // referent with the SATB barrier.
 278 
 279 #if INCLUDE_ALL_GCS
 280 static bool is_java_lang_ref_Reference_access(oop o, jlong offset) {
 281   if (offset == java_lang_ref_Reference::referent_offset && o != NULL) {
 282     Klass* k = o->klass();
 283     if (InstanceKlass::cast(k)->reference_type() != REF_NONE) {
 284       assert(InstanceKlass::cast(k)->is_subclass_of(SystemDictionary::Reference_klass()), "sanity");
 285       return true;
 286     }
 287   }
 288   return false;
 289 }
 290 #endif
 291 
 292 static void ensure_satb_referent_alive(oop o, jlong offset, oop v) {
 293 #if INCLUDE_ALL_GCS
 294   if (UseG1GC && v != NULL && is_java_lang_ref_Reference_access(o, offset)) {
 295     G1SATBCardTableModRefBS::enqueue(v);
 296   }
 297 #endif
 298 }
 299 
 300 // These functions allow a null base pointer with an arbitrary address.
 301 // But if the base pointer is non-null, the offset should make some sense.
 302 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
 303 UNSAFE_ENTRY(jobject, Unsafe_GetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
 304   oop p = JNIHandles::resolve(obj);
 305   oop v;
 306 
 307   if (UseCompressedOops) {
 308     narrowOop n = *(narrowOop*)index_oop_from_field_offset_long(p, offset);
 309     v = oopDesc::decode_heap_oop(n);
 310   } else {
 311     v = *(oop*)index_oop_from_field_offset_long(p, offset);
 312   }
 313 
 314   ensure_satb_referent_alive(p, offset, v);
 315 
 316   return JNIHandles::make_local(env, v);
 317 } UNSAFE_END
 318 
 319 UNSAFE_ENTRY(void, Unsafe_PutObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
 320   oop x = JNIHandles::resolve(x_h);
 321   oop p = JNIHandles::resolve(obj);
 322 
 323   if (UseCompressedOops) {
 324     oop_store((narrowOop*)index_oop_from_field_offset_long(p, offset), x);
 325   } else {
 326     oop_store((oop*)index_oop_from_field_offset_long(p, offset), x);
 327   }
 328 } UNSAFE_END
 329 
 330 UNSAFE_ENTRY(jobject, Unsafe_GetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
 331   oop p = JNIHandles::resolve(obj);
 332   void* addr = index_oop_from_field_offset_long(p, offset);
 333 
 334   volatile oop v;
 335 
 336   if (support_IRIW_for_not_multiple_copy_atomic_cpu) {
 337     OrderAccess::fence();
 338   }
 339 
 340   if (UseCompressedOops) {
 341     volatile narrowOop n = *(volatile narrowOop*) addr;
 342     (void)const_cast<oop&>(v = oopDesc::decode_heap_oop(n));
 343   } else {
 344     (void)const_cast<oop&>(v = *(volatile oop*) addr);
 345   }
 346 
 347   ensure_satb_referent_alive(p, offset, v);
 348 
 349   OrderAccess::acquire();
 350   return JNIHandles::make_local(env, v);
 351 } UNSAFE_END
 352 
 353 UNSAFE_ENTRY(void, Unsafe_PutObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
 354   oop x = JNIHandles::resolve(x_h);
 355   oop p = JNIHandles::resolve(obj);
 356   void* addr = index_oop_from_field_offset_long(p, offset);
 357   OrderAccess::release();
 358 
 359   if (UseCompressedOops) {
 360     oop_store((narrowOop*)addr, x);
 361   } else {
 362     oop_store((oop*)addr, x);
 363   }
 364 
 365   OrderAccess::fence();
 366 } UNSAFE_END
 367 
 368 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
 369   oop v = *(oop*) (address) addr;
 370 
 371   return JNIHandles::make_local(env, v);
 372 } UNSAFE_END
 373 
 374 #ifndef SUPPORTS_NATIVE_CX8
 375 
 376 // VM_Version::supports_cx8() is a surrogate for 'supports atomic long memory ops'.
 377 //
 378 // On platforms which do not support atomic compare-and-swap of jlong (8 byte)
 379 // values we have to use a lock-based scheme to enforce atomicity. This has to be
 380 // applied to all Unsafe operations that set the value of a jlong field. Even so
 381 // the compareAndSetLong operation will not be atomic with respect to direct stores
 382 // to the field from Java code. It is important therefore that any Java code that
 383 // utilizes these Unsafe jlong operations does not perform direct stores. To permit
 384 // direct loads of the field from Java code we must also use Atomic::store within the
 385 // locked regions. And for good measure, in case there are direct stores, we also
 386 // employ Atomic::load within those regions. Note that the field in question must be
 387 // volatile and so must have atomic load/store accesses applied at the Java level.
 388 //
 389 // The locking scheme could utilize a range of strategies for controlling the locking
 390 // granularity: from a lock per-field through to a single global lock. The latter is
 391 // the simplest and is used for the current implementation. Note that the Java object
 392 // that contains the field, can not, in general, be used for locking. To do so can lead
 393 // to deadlocks as we may introduce locking into what appears to the Java code to be a
 394 // lock-free path.
 395 //
 396 // As all the locked-regions are very short and themselves non-blocking we can treat
 397 // them as leaf routines and elide safepoint checks (ie we don't perform any thread
 398 // state transitions even when blocking for the lock). Note that if we do choose to
 399 // add safepoint checks and thread state transitions, we must ensure that we calculate
 400 // the address of the field _after_ we have acquired the lock, else the object may have
 401 // been moved by the GC
 402 
 403 UNSAFE_ENTRY(jlong, Unsafe_GetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
 404   if (VM_Version::supports_cx8()) {
 405     return MemoryAccess(thread, obj, offset).get_volatile<jlong>();
 406   } else {
 407     return MemoryAccess(thread, obj, offset).get_jlong_locked();
 408   }
 409 } UNSAFE_END
 410 
 411 UNSAFE_ENTRY(void, Unsafe_PutLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x)) {
 412   if (VM_Version::supports_cx8()) {
 413     MemoryAccess(thread, obj, offset).put_volatile<jlong>(x);
 414   } else {
 415     MemoryAccess(thread, obj, offset).put_jlong_locked(x);
 416   }
 417 } UNSAFE_END
 418 
 419 #endif // not SUPPORTS_NATIVE_CX8
 420 
 421 UNSAFE_LEAF(jboolean, Unsafe_isBigEndian0(JNIEnv *env, jobject unsafe)) {
 422 #ifdef VM_LITTLE_ENDIAN
 423   return false;
 424 #else
 425   return true;
 426 #endif
 427 } UNSAFE_END
 428 
 429 UNSAFE_LEAF(jint, Unsafe_unalignedAccess0(JNIEnv *env, jobject unsafe)) {
 430   return UseUnalignedAccesses;
 431 } UNSAFE_END
 432 
 433 #define DEFINE_GETSETOOP(java_type, Type) \
 434  \
 435 UNSAFE_ENTRY(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
 436   return MemoryAccess(thread, obj, offset).get<java_type>(); \
 437 } UNSAFE_END \
 438  \
 439 UNSAFE_ENTRY(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
 440   MemoryAccess(thread, obj, offset).put<java_type>(x); \
 441 } UNSAFE_END \
 442  \
 443 // END DEFINE_GETSETOOP.
 444 
 445 DEFINE_GETSETOOP(jboolean, Boolean)
 446 DEFINE_GETSETOOP(jbyte, Byte)
 447 DEFINE_GETSETOOP(jshort, Short);
 448 DEFINE_GETSETOOP(jchar, Char);
 449 DEFINE_GETSETOOP(jint, Int);
 450 DEFINE_GETSETOOP(jlong, Long);
 451 DEFINE_GETSETOOP(jfloat, Float);
 452 DEFINE_GETSETOOP(jdouble, Double);
 453 
 454 #undef DEFINE_GETSETOOP
 455 
 456 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
 457  \
 458 UNSAFE_ENTRY(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
 459   return MemoryAccess(thread, obj, offset).get_volatile<java_type>(); \
 460 } UNSAFE_END \
 461  \
 462 UNSAFE_ENTRY(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
 463   MemoryAccess(thread, obj, offset).put_volatile<java_type>(x); \
 464 } UNSAFE_END \
 465  \
 466 // END DEFINE_GETSETOOP_VOLATILE.
 467 
 468 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
 469 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
 470 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
 471 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
 472 DEFINE_GETSETOOP_VOLATILE(jint, Int);
 473 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
 474 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
 475 
 476 #ifdef SUPPORTS_NATIVE_CX8
 477 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
 478 #endif
 479 
 480 #undef DEFINE_GETSETOOP_VOLATILE
 481 
 482 UNSAFE_LEAF(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe)) {
 483   OrderAccess::acquire();
 484 } UNSAFE_END
 485 
 486 UNSAFE_LEAF(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe)) {
 487   OrderAccess::release();
 488 } UNSAFE_END
 489 
 490 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
 491   OrderAccess::fence();
 492 } UNSAFE_END
 493 
 494 ////// Allocation requests
 495 
 496 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
 497   ThreadToNativeFromVM ttnfv(thread);
 498   return env->AllocObject(cls);
 499 } UNSAFE_END
 500 
 501 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
 502   size_t sz = (size_t)size;
 503 
 504   sz = round_to(sz, HeapWordSize);
 505   void* x = os::malloc(sz, mtInternal);
 506 
 507   return addr_to_java(x);
 508 } UNSAFE_END
 509 
 510 UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) {
 511   void* p = addr_from_java(addr);
 512   size_t sz = (size_t)size;
 513   sz = round_to(sz, HeapWordSize);
 514 
 515   void* x = os::realloc(p, sz, mtInternal);
 516 
 517   return addr_to_java(x);
 518 } UNSAFE_END
 519 
 520 UNSAFE_ENTRY(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
 521   void* p = addr_from_java(addr);
 522 
 523   os::free(p);
 524 } UNSAFE_END
 525 
 526 UNSAFE_ENTRY(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
 527   size_t sz = (size_t)size;
 528 
 529   oop base = JNIHandles::resolve(obj);
 530   void* p = index_oop_from_field_offset_long(base, offset);
 531 
 532   Copy::fill_to_memory_atomic(p, sz, value);
 533 } UNSAFE_END
 534 
 535 UNSAFE_ENTRY(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
 536   size_t sz = (size_t)size;
 537 
 538   oop srcp = JNIHandles::resolve(srcObj);
 539   oop dstp = JNIHandles::resolve(dstObj);
 540 
 541   void* src = index_oop_from_field_offset_long(srcp, srcOffset);
 542   void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
 543 
 544   Copy::conjoint_memory_atomic(src, dst, sz);
 545 } UNSAFE_END
 546 
 547 // This function is a leaf since if the source and destination are both in native memory
 548 // the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
 549 // If either source or destination (or both) are on the heap, the function will enter VM using
 550 // JVM_ENTRY_FROM_LEAF
 551 UNSAFE_LEAF(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
 552   size_t sz = (size_t)size;
 553   size_t esz = (size_t)elemSize;
 554 
 555   if (srcObj == NULL && dstObj == NULL) {
 556     // Both src & dst are in native memory
 557     address src = (address)srcOffset;
 558     address dst = (address)dstOffset;
 559 
 560     Copy::conjoint_swap(src, dst, sz, esz);
 561   } else {
 562     // At least one of src/dst are on heap, transition to VM to access raw pointers
 563 
 564     JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory0) {
 565       oop srcp = JNIHandles::resolve(srcObj);
 566       oop dstp = JNIHandles::resolve(dstObj);
 567 
 568       address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
 569       address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
 570 
 571       Copy::conjoint_swap(src, dst, sz, esz);
 572     } JVM_END
 573   }
 574 } UNSAFE_END
 575 
 576 ////// Random queries
 577 
 578 UNSAFE_LEAF(jint, Unsafe_AddressSize0(JNIEnv *env, jobject unsafe)) {
 579   return sizeof(void*);
 580 } UNSAFE_END
 581 
 582 UNSAFE_LEAF(jint, Unsafe_PageSize()) {
 583   return os::vm_page_size();
 584 } UNSAFE_END
 585 
 586 static jint find_field_offset(jobject field, int must_be_static, TRAPS) {
 587   assert(field != NULL, "field must not be NULL");
 588 
 589   oop reflected   = JNIHandles::resolve_non_null(field);
 590   oop mirror      = java_lang_reflect_Field::clazz(reflected);
 591   Klass* k        = java_lang_Class::as_Klass(mirror);
 592   int slot        = java_lang_reflect_Field::slot(reflected);
 593   int modifiers   = java_lang_reflect_Field::modifiers(reflected);
 594 
 595   if (must_be_static >= 0) {
 596     int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
 597     if (must_be_static != really_is_static) {
 598       THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 599     }
 600   }
 601 
 602   int offset = InstanceKlass::cast(k)->field_offset(slot);
 603   return field_offset_from_byte_offset(offset);
 604 }
 605 
 606 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
 607   return find_field_offset(field, 0, THREAD);
 608 } UNSAFE_END
 609 
 610 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
 611   return find_field_offset(field, 1, THREAD);
 612 } UNSAFE_END
 613 
 614 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
 615   assert(field != NULL, "field must not be NULL");
 616 
 617   // Note:  In this VM implementation, a field address is always a short
 618   // offset from the base of a a klass metaobject.  Thus, the full dynamic
 619   // range of the return type is never used.  However, some implementations
 620   // might put the static field inside an array shared by many classes,
 621   // or even at a fixed address, in which case the address could be quite
 622   // large.  In that last case, this function would return NULL, since
 623   // the address would operate alone, without any base pointer.
 624 
 625   oop reflected   = JNIHandles::resolve_non_null(field);
 626   oop mirror      = java_lang_reflect_Field::clazz(reflected);
 627   int modifiers   = java_lang_reflect_Field::modifiers(reflected);
 628 
 629   if ((modifiers & JVM_ACC_STATIC) == 0) {
 630     THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 631   }
 632 
 633   return JNIHandles::make_local(env, mirror);
 634 } UNSAFE_END
 635 
 636 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
 637   assert(clazz != NULL, "clazz must not be NULL");
 638 
 639   oop mirror = JNIHandles::resolve_non_null(clazz);
 640 
 641   Klass* klass = java_lang_Class::as_Klass(mirror);
 642   if (klass != NULL && klass->should_be_initialized()) {
 643     InstanceKlass* k = InstanceKlass::cast(klass);
 644     k->initialize(CHECK);
 645   }
 646 }
 647 UNSAFE_END
 648 
 649 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
 650   assert(clazz != NULL, "clazz must not be NULL");
 651 
 652   oop mirror = JNIHandles::resolve_non_null(clazz);
 653   Klass* klass = java_lang_Class::as_Klass(mirror);
 654 
 655   if (klass != NULL && klass->should_be_initialized()) {
 656     return true;
 657   }
 658 
 659   return false;
 660 }
 661 UNSAFE_END
 662 
 663 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
 664   assert(clazz != NULL, "clazz must not be NULL");
 665 
 666   oop mirror = JNIHandles::resolve_non_null(clazz);
 667   Klass* k = java_lang_Class::as_Klass(mirror);
 668 
 669   if (k == NULL || !k->is_array_klass()) {
 670     THROW(vmSymbols::java_lang_InvalidClassException());
 671   } else if (k->is_objArray_klass()) {
 672     base  = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
 673     scale = heapOopSize;
 674   } else if (k->is_typeArray_klass()) {
 675     TypeArrayKlass* tak = TypeArrayKlass::cast(k);
 676     base  = tak->array_header_in_bytes();
 677     assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
 678     scale = (1 << tak->log2_element_size());
 679   } else {
 680     ShouldNotReachHere();
 681   }
 682 }
 683 
 684 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
 685   int base = 0, scale = 0;
 686   getBaseAndScale(base, scale, clazz, CHECK_0);
 687 
 688   return field_offset_from_byte_offset(base);
 689 } UNSAFE_END
 690 
 691 
 692 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
 693   int base = 0, scale = 0;
 694   getBaseAndScale(base, scale, clazz, CHECK_0);
 695 
 696   // This VM packs both fields and array elements down to the byte.
 697   // But watch out:  If this changes, so that array references for
 698   // a given primitive type (say, T_BOOLEAN) use different memory units
 699   // than fields, this method MUST return zero for such arrays.
 700   // For example, the VM used to store sub-word sized fields in full
 701   // words in the object layout, so that accessors like getByte(Object,int)
 702   // did not really do what one might expect for arrays.  Therefore,
 703   // this function used to report a zero scale factor, so that the user
 704   // would know not to attempt to access sub-word array elements.
 705   // // Code for unpacked fields:
 706   // if (scale < wordSize)  return 0;
 707 
 708   // The following allows for a pretty general fieldOffset cookie scheme,
 709   // but requires it to be linear in byte offset.
 710   return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
 711 } UNSAFE_END
 712 
 713 
 714 static inline void throw_new(JNIEnv *env, const char *ename) {
 715   char buf[100];
 716 
 717   jio_snprintf(buf, 100, "%s%s", "java/lang/", ename);
 718 
 719   jclass cls = env->FindClass(buf);
 720   if (env->ExceptionCheck()) {
 721     env->ExceptionClear();
 722     tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", buf);
 723     return;
 724   }
 725 
 726   env->ThrowNew(cls, NULL);
 727 }
 728 
 729 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
 730   // Code lifted from JDK 1.3 ClassLoader.c
 731 
 732   jbyte *body;
 733   char *utfName = NULL;
 734   jclass result = 0;
 735   char buf[128];
 736 
 737   assert(data != NULL, "Class bytes must not be NULL");
 738   assert(length >= 0, "length must not be negative: %d", length);
 739 
 740   if (UsePerfData) {
 741     ClassLoader::unsafe_defineClassCallCounter()->inc();
 742   }
 743 
 744   body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
 745   if (body == NULL) {
 746     throw_new(env, "OutOfMemoryError");
 747     return 0;
 748   }
 749 
 750   env->GetByteArrayRegion(data, offset, length, body);
 751   if (env->ExceptionOccurred()) {
 752     goto free_body;
 753   }
 754 
 755   if (name != NULL) {
 756     uint len = env->GetStringUTFLength(name);
 757     int unicode_len = env->GetStringLength(name);
 758 
 759     if (len >= sizeof(buf)) {
 760       utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
 761       if (utfName == NULL) {
 762         throw_new(env, "OutOfMemoryError");
 763         goto free_body;
 764       }
 765     } else {
 766       utfName = buf;
 767     }
 768 
 769     env->GetStringUTFRegion(name, 0, unicode_len, utfName);
 770 
 771     for (uint i = 0; i < len; i++) {
 772       if (utfName[i] == '.')   utfName[i] = '/';
 773     }
 774   }
 775 
 776   result = JVM_DefineClass(env, utfName, loader, body, length, pd);
 777 
 778   if (utfName && utfName != buf) {
 779     FREE_C_HEAP_ARRAY(char, utfName);
 780   }
 781 
 782  free_body:
 783   FREE_C_HEAP_ARRAY(jbyte, body);
 784   return result;
 785 }
 786 
 787 
 788 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
 789   ThreadToNativeFromVM ttnfv(thread);
 790 
 791   return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
 792 } UNSAFE_END
 793 
 794 
 795 // define a class but do not make it known to the class loader or system dictionary
 796 // - host_class:  supplies context for linkage, access control, protection domain, and class loader
 797 //                if host_class is itself anonymous then it is replaced with its host class.
 798 // - data:  bytes of a class file, a raw memory address (length gives the number of bytes)
 799 // - cp_patches:  where non-null entries exist, they replace corresponding CP entries in data
 800 
 801 // When you load an anonymous class U, it works as if you changed its name just before loading,
 802 // to a name that you will never use again.  Since the name is lost, no other class can directly
 803 // link to any member of U.  Just after U is loaded, the only way to use it is reflectively,
 804 // through java.lang.Class methods like Class.newInstance.
 805 
 806 // The package of an anonymous class must either match its host's class's package or be in the
 807 // unnamed package.  If it is in the unnamed package then it will be put in its host class's
 808 // package.
 809 //
 810 
 811 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
 812 // An anonymous class also has special privileges to access any member of its host class.
 813 // This is the main reason why this loading operation is unsafe.  The purpose of this is to
 814 // allow language implementations to simulate "open classes"; a host class in effect gets
 815 // new code when an anonymous class is loaded alongside it.  A less convenient but more
 816 // standard way to do this is with reflection, which can also be set to ignore access
 817 // restrictions.
 818 
 819 // Access into an anonymous class is possible only through reflection.  Therefore, there
 820 // are no special access rules for calling into an anonymous class.  The relaxed access
 821 // rule for the host class is applied in the opposite direction:  A host class reflectively
 822 // access one of its anonymous classes.
 823 
 824 // If you load the same bytecodes twice, you get two different classes.  You can reload
 825 // the same bytecodes with or without varying CP patches.
 826 
 827 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
 828 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
 829 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
 830 
 831 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
 832 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
 833 // It is not possible for a named class, or an older anonymous class, to refer by
 834 // name (via its CP) to a newer anonymous class.
 835 
 836 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
 837 // or type descriptors used in the loaded anonymous class.
 838 
 839 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
 840 // instead of "dead" strings.  A compiled statement like println((Object)"hello") can
 841 // be changed to println(greeting), where greeting is an arbitrary object created before
 842 // the anonymous class is loaded.  This is useful in dynamic languages, in which
 843 // various kinds of metaobjects must be introduced as constants into bytecode.
 844 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
 845 // not just a literal string.  For such ldc instructions, the verifier uses the
 846 // type Object instead of String, if the loaded constant is not in fact a String.
 847 
 848 static instanceKlassHandle
 849 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
 850                                  jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
 851                                  u1** temp_alloc,
 852                                  TRAPS) {
 853   assert(host_class != NULL, "host_class must not be NULL");
 854   assert(data != NULL, "data must not be NULL");
 855 
 856   if (UsePerfData) {
 857     ClassLoader::unsafe_defineClassCallCounter()->inc();
 858   }
 859 
 860   jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
 861   assert(length >= 0, "class_bytes_length must not be negative: %d", length);
 862 
 863   int class_bytes_length = (int) length;
 864 
 865   u1* class_bytes = NEW_C_HEAP_ARRAY(u1, length, mtInternal);
 866   if (class_bytes == NULL) {
 867     THROW_0(vmSymbols::java_lang_OutOfMemoryError());
 868   }
 869 
 870   // caller responsible to free it:
 871   *temp_alloc = class_bytes;
 872 
 873   jbyte* array_base = typeArrayOop(JNIHandles::resolve_non_null(data))->byte_at_addr(0);
 874   Copy::conjoint_jbytes(array_base, class_bytes, length);
 875 
 876   objArrayHandle cp_patches_h;
 877   if (cp_patches_jh != NULL) {
 878     oop p = JNIHandles::resolve_non_null(cp_patches_jh);
 879     assert(p->is_objArray(), "cp_patches must be an object[]");
 880     cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
 881   }
 882 
 883   const Klass* host_klass = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class));
 884 
 885   // Make sure it's the real host class, not another anonymous class.
 886   while (host_klass != NULL && host_klass->is_instance_klass() &&
 887          InstanceKlass::cast(host_klass)->is_anonymous()) {
 888     host_klass = InstanceKlass::cast(host_klass)->host_klass();
 889   }
 890 
 891   // Primitive types have NULL Klass* fields in their java.lang.Class instances.
 892   if (host_klass == NULL) {
 893     THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), "Host class is null");
 894   }
 895 
 896   assert(host_klass->is_instance_klass(), "Host class must be an instance class");
 897 
 898   const char* host_source = host_klass->external_name();
 899   Handle      host_loader(THREAD, host_klass->class_loader());
 900   Handle      host_domain(THREAD, host_klass->protection_domain());
 901 
 902   GrowableArray<Handle>* cp_patches = NULL;
 903 
 904   if (cp_patches_h.not_null()) {
 905     int alen = cp_patches_h->length();
 906 
 907     for (int i = alen-1; i >= 0; i--) {
 908       oop p = cp_patches_h->obj_at(i);
 909       if (p != NULL) {
 910         Handle patch(THREAD, p);
 911 
 912         if (cp_patches == NULL) {
 913           cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
 914         }
 915 
 916         cp_patches->at_put(i, patch);
 917       }
 918     }
 919   }
 920 
 921   ClassFileStream st(class_bytes, class_bytes_length, host_source, ClassFileStream::verify);
 922 
 923   Symbol* no_class_name = NULL;
 924   Klass* anonk = SystemDictionary::parse_stream(no_class_name,
 925                                                 host_loader,
 926                                                 host_domain,
 927                                                 &st,
 928                                                 InstanceKlass::cast(host_klass),
 929                                                 cp_patches,
 930                                                 CHECK_NULL);
 931   if (anonk == NULL) {
 932     return NULL;
 933   }
 934 
 935   return instanceKlassHandle(THREAD, anonk);
 936 }
 937 
 938 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass0(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh)) {
 939   ResourceMark rm(THREAD);
 940 
 941   instanceKlassHandle anon_klass;
 942   jobject res_jh = NULL;
 943   u1* temp_alloc = NULL;
 944 
 945   anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data, cp_patches_jh, &temp_alloc, THREAD);
 946   if (anon_klass() != NULL) {
 947     res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
 948   }
 949 
 950   // try/finally clause:
 951   if (temp_alloc != NULL) {
 952     FREE_C_HEAP_ARRAY(u1, temp_alloc);
 953   }
 954 
 955   // The anonymous class loader data has been artificially been kept alive to
 956   // this point.   The mirror and any instances of this class have to keep
 957   // it alive afterwards.
 958   if (anon_klass() != NULL) {
 959     anon_klass->class_loader_data()->dec_keep_alive();
 960   }
 961 
 962   // let caller initialize it as needed...
 963 
 964   return (jclass) res_jh;
 965 } UNSAFE_END
 966 
 967 
 968 
 969 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
 970   ThreadToNativeFromVM ttnfv(thread);
 971   env->Throw(thr);
 972 } UNSAFE_END
 973 
 974 // JSR166 ------------------------------------------------------------------
 975 
 976 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
 977   oop x = JNIHandles::resolve(x_h);
 978   oop e = JNIHandles::resolve(e_h);
 979   oop p = JNIHandles::resolve(obj);
 980   HeapWord* addr = (HeapWord *)index_oop_from_field_offset_long(p, offset);
 981   oop res = oopDesc::atomic_compare_exchange_oop(x, addr, e, true);
 982   if (res == e) {
 983     update_barrier_set((void*)addr, x);
 984   }
 985   return JNIHandles::make_local(env, res);
 986 } UNSAFE_END
 987 
 988 UNSAFE_ENTRY(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
 989   oop p = JNIHandles::resolve(obj);
 990   jint* addr = (jint *) index_oop_from_field_offset_long(p, offset);
 991 
 992   return (jint)(Atomic::cmpxchg(x, addr, e));
 993 } UNSAFE_END
 994 
 995 UNSAFE_ENTRY(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
 996   Handle p(THREAD, JNIHandles::resolve(obj));
 997   jlong* addr = (jlong*)index_oop_from_field_offset_long(p(), offset);
 998 
 999 #ifdef SUPPORTS_NATIVE_CX8
1000   return (jlong)(Atomic::cmpxchg(x, addr, e));
1001 #else
1002   if (VM_Version::supports_cx8()) {
1003     return (jlong)(Atomic::cmpxchg(x, addr, e));
1004   } else {
1005     MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
1006 
1007     jlong val = Atomic::load(addr);
1008     if (val == e) {
1009       Atomic::store(x, addr);
1010     }
1011     return val;
1012   }
1013 #endif
1014 } UNSAFE_END
1015 
1016 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1017   oop x = JNIHandles::resolve(x_h);
1018   oop e = JNIHandles::resolve(e_h);
1019   oop p = JNIHandles::resolve(obj);
1020   HeapWord* addr = (HeapWord *)index_oop_from_field_offset_long(p, offset);
1021   oop res = oopDesc::atomic_compare_exchange_oop(x, addr, e, true);
1022   if (res != e) {
1023     return false;
1024   }
1025 
1026   update_barrier_set((void*)addr, x);
1027 
1028   return true;
1029 } UNSAFE_END
1030 
1031 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1032   oop p = JNIHandles::resolve(obj);
1033   jint* addr = (jint *)index_oop_from_field_offset_long(p, offset);
1034 
1035   return (jint)(Atomic::cmpxchg(x, addr, e)) == e;
1036 } UNSAFE_END
1037 
1038 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1039   Handle p(THREAD, JNIHandles::resolve(obj));
1040   jlong* addr = (jlong*)index_oop_from_field_offset_long(p(), offset);
1041 
1042 #ifdef SUPPORTS_NATIVE_CX8
1043   return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1044 #else
1045   if (VM_Version::supports_cx8()) {
1046     return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1047   } else {
1048     MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
1049 
1050     jlong val = Atomic::load(addr);
1051     if (val != e) {
1052       return false;
1053     }
1054 
1055     Atomic::store(x, addr);
1056     return true;
1057   }
1058 #endif
1059 } UNSAFE_END
1060 
1061 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
1062   EventThreadPark event;
1063   HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1064 
1065   JavaThreadParkedState jtps(thread, time != 0);
1066   thread->parker()->park(isAbsolute != 0, time);
1067 
1068   HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1069 
1070   if (event.should_commit()) {
1071     oop obj = thread->current_park_blocker();
1072     event.set_parkedClass((obj != NULL) ? obj->klass() : NULL);
1073     event.set_timeout(time);
1074     event.set_address((obj != NULL) ? (TYPE_ADDRESS) cast_from_oop<uintptr_t>(obj) : 0);
1075     event.commit();
1076   }
1077 } UNSAFE_END
1078 
1079 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
1080   Parker* p = NULL;
1081 
1082   if (jthread != NULL) {
1083     oop java_thread = JNIHandles::resolve_non_null(jthread);
1084     if (java_thread != NULL) {
1085       jlong lp = java_lang_Thread::park_event(java_thread);
1086       if (lp != 0) {
1087         // This cast is OK even though the jlong might have been read
1088         // non-atomically on 32bit systems, since there, one word will
1089         // always be zero anyway and the value set is always the same
1090         p = (Parker*)addr_from_java(lp);
1091       } else {
1092         // Grab lock if apparently null or using older version of library
1093         MutexLocker mu(Threads_lock);
1094         java_thread = JNIHandles::resolve_non_null(jthread);
1095 
1096         if (java_thread != NULL) {
1097           JavaThread* thr = java_lang_Thread::thread(java_thread);
1098           if (thr != NULL) {
1099             p = thr->parker();
1100             if (p != NULL) { // Bind to Java thread for next time.
1101               java_lang_Thread::set_park_event(java_thread, addr_to_java(p));
1102             }
1103           }
1104         }
1105       }
1106     }
1107   }
1108 
1109   if (p != NULL) {
1110     HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1111     p->unpark();
1112   }
1113 } UNSAFE_END
1114 
1115 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
1116   const int max_nelem = 3;
1117   double la[max_nelem];
1118   jint ret;
1119 
1120   typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1121   assert(a->is_typeArray(), "must be type array");
1122 
1123   ret = os::loadavg(la, nelem);
1124   if (ret == -1) {
1125     return -1;
1126   }
1127 
1128   // if successful, ret is the number of samples actually retrieved.
1129   assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1130   switch(ret) {
1131     case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1132     case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1133     case 1: a->double_at_put(0, (jdouble)la[0]); break;
1134   }
1135 
1136   return ret;
1137 } UNSAFE_END
1138 
1139 
1140 /// JVM_RegisterUnsafeMethods
1141 
1142 #define ADR "J"
1143 
1144 #define LANG "Ljava/lang/"
1145 
1146 #define OBJ LANG "Object;"
1147 #define CLS LANG "Class;"
1148 #define FLD LANG "reflect/Field;"
1149 #define THR LANG "Throwable;"
1150 
1151 #define DC_Args  LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1152 #define DAC_Args CLS "[B[" OBJ
1153 
1154 #define CC (char*)  /*cast a literal from (const char*)*/
1155 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1156 
1157 #define DECLARE_GETPUTOOP(Type, Desc) \
1158     {CC "get" #Type,      CC "(" OBJ "J)" #Desc,       FN_PTR(Unsafe_Get##Type)}, \
1159     {CC "put" #Type,      CC "(" OBJ "J" #Desc ")V",   FN_PTR(Unsafe_Put##Type)}, \
1160     {CC "get" #Type "Volatile",      CC "(" OBJ "J)" #Desc,       FN_PTR(Unsafe_Get##Type##Volatile)}, \
1161     {CC "put" #Type "Volatile",      CC "(" OBJ "J" #Desc ")V",   FN_PTR(Unsafe_Put##Type##Volatile)}
1162 
1163 
1164 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1165     {CC "getObject",        CC "(" OBJ "J)" OBJ "",   FN_PTR(Unsafe_GetObject)},
1166     {CC "putObject",        CC "(" OBJ "J" OBJ ")V",  FN_PTR(Unsafe_PutObject)},
1167     {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "",   FN_PTR(Unsafe_GetObjectVolatile)},
1168     {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V",  FN_PTR(Unsafe_PutObjectVolatile)},
1169 
1170     {CC "getUncompressedObject", CC "(" ADR ")" OBJ,  FN_PTR(Unsafe_GetUncompressedObject)},
1171 
1172     DECLARE_GETPUTOOP(Boolean, Z),
1173     DECLARE_GETPUTOOP(Byte, B),
1174     DECLARE_GETPUTOOP(Short, S),
1175     DECLARE_GETPUTOOP(Char, C),
1176     DECLARE_GETPUTOOP(Int, I),
1177     DECLARE_GETPUTOOP(Long, J),
1178     DECLARE_GETPUTOOP(Float, F),
1179     DECLARE_GETPUTOOP(Double, D),
1180 
1181     {CC "allocateMemory0",    CC "(J)" ADR,              FN_PTR(Unsafe_AllocateMemory0)},
1182     {CC "reallocateMemory0",  CC "(" ADR "J)" ADR,       FN_PTR(Unsafe_ReallocateMemory0)},
1183     {CC "freeMemory0",        CC "(" ADR ")V",           FN_PTR(Unsafe_FreeMemory0)},
1184 
1185     {CC "objectFieldOffset0", CC "(" FLD ")J",           FN_PTR(Unsafe_ObjectFieldOffset0)},
1186     {CC "staticFieldOffset0", CC "(" FLD ")J",           FN_PTR(Unsafe_StaticFieldOffset0)},
1187     {CC "staticFieldBase0",   CC "(" FLD ")" OBJ,        FN_PTR(Unsafe_StaticFieldBase0)},
1188     {CC "ensureClassInitialized0", CC "(" CLS ")V",      FN_PTR(Unsafe_EnsureClassInitialized0)},
1189     {CC "arrayBaseOffset0",   CC "(" CLS ")I",           FN_PTR(Unsafe_ArrayBaseOffset0)},
1190     {CC "arrayIndexScale0",   CC "(" CLS ")I",           FN_PTR(Unsafe_ArrayIndexScale0)},
1191     {CC "addressSize0",       CC "()I",                  FN_PTR(Unsafe_AddressSize0)},
1192     {CC "pageSize",           CC "()I",                  FN_PTR(Unsafe_PageSize)},
1193 
1194     {CC "defineClass0",       CC "(" DC_Args ")" CLS,    FN_PTR(Unsafe_DefineClass0)},
1195     {CC "allocateInstance",   CC "(" CLS ")" OBJ,        FN_PTR(Unsafe_AllocateInstance)},
1196     {CC "throwException",     CC "(" THR ")V",           FN_PTR(Unsafe_ThrowException)},
1197     {CC "compareAndSetObject",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetObject)},
1198     {CC "compareAndSetInt",   CC "(" OBJ "J""I""I"")Z",  FN_PTR(Unsafe_CompareAndSetInt)},
1199     {CC "compareAndSetLong",  CC "(" OBJ "J""J""J"")Z",  FN_PTR(Unsafe_CompareAndSetLong)},
1200     {CC "compareAndExchangeObject", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeObject)},
1201     {CC "compareAndExchangeInt",  CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1202     {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1203 
1204     {CC "park",               CC "(ZJ)V",                FN_PTR(Unsafe_Park)},
1205     {CC "unpark",             CC "(" OBJ ")V",           FN_PTR(Unsafe_Unpark)},
1206 
1207     {CC "getLoadAverage0",    CC "([DI)I",               FN_PTR(Unsafe_GetLoadAverage0)},
1208 
1209     {CC "copyMemory0",        CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1210     {CC "copySwapMemory0",    CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1211     {CC "setMemory0",         CC "(" OBJ "JJB)V",        FN_PTR(Unsafe_SetMemory0)},
1212 
1213     {CC "defineAnonymousClass0", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass0)},
1214 
1215     {CC "shouldBeInitialized0", CC "(" CLS ")Z",         FN_PTR(Unsafe_ShouldBeInitialized0)},
1216 
1217     {CC "loadFence",          CC "()V",                  FN_PTR(Unsafe_LoadFence)},
1218     {CC "storeFence",         CC "()V",                  FN_PTR(Unsafe_StoreFence)},
1219     {CC "fullFence",          CC "()V",                  FN_PTR(Unsafe_FullFence)},
1220 
1221     {CC "isBigEndian0",       CC "()Z",                  FN_PTR(Unsafe_isBigEndian0)},
1222     {CC "unalignedAccess0",   CC "()Z",                  FN_PTR(Unsafe_unalignedAccess0)}
1223 };
1224 
1225 #undef CC
1226 #undef FN_PTR
1227 
1228 #undef ADR
1229 #undef LANG
1230 #undef OBJ
1231 #undef CLS
1232 #undef FLD
1233 #undef THR
1234 #undef DC_Args
1235 #undef DAC_Args
1236 
1237 #undef DECLARE_GETPUTOOP
1238 
1239 
1240 // This function is exported, used by NativeLookup.
1241 // The Unsafe_xxx functions above are called only from the interpreter.
1242 // The optimizer looks at names and signatures to recognize
1243 // individual functions.
1244 
1245 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1246   ThreadToNativeFromVM ttnfv(thread);
1247 
1248   int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1249   guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1250 } JVM_END