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 "jni.h"
  27 #include "classfile/classFileStream.hpp"
  28 #include "classfile/vmSymbols.hpp"
  29 #include "memory/allocation.inline.hpp"
  30 #include "memory/resourceArea.hpp"
  31 #include "oops/fieldStreams.hpp"
  32 #include "oops/objArrayOop.inline.hpp"
  33 #include "oops/oop.inline.hpp"
  34 #include "prims/jvm.h"
  35 #include "prims/unsafe.hpp"
  36 #include "runtime/atomic.hpp"
  37 #include "runtime/globals.hpp"
  38 #include "runtime/interfaceSupport.hpp"
  39 #include "runtime/orderAccess.inline.hpp"
  40 #include "runtime/reflection.hpp"
  41 #include "runtime/vm_version.hpp"
  42 #include "services/threadService.hpp"
  43 #include "trace/tracing.hpp"
  44 #include "utilities/align.hpp"
  45 #include "utilities/copy.hpp"
  46 #include "utilities/dtrace.hpp"
  47 #include "utilities/macros.hpp"
  48 #if INCLUDE_ALL_GCS
  49 #include "gc/g1/g1SATBCardTableModRefBS.hpp"
  50 #endif // INCLUDE_ALL_GCS
  51 
  52 /**
  53  * Implementation of the jdk.internal.misc.Unsafe class
  54  */
  55 
  56 
  57 #define MAX_OBJECT_SIZE \
  58   ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
  59     + ((julong)max_jint * sizeof(double)) )
  60 
  61 
  62 #define UNSAFE_ENTRY(result_type, header) \
  63   JVM_ENTRY(static result_type, header)
  64 
  65 #define UNSAFE_LEAF(result_type, header) \
  66   JVM_LEAF(static result_type, header)
  67 
  68 #define UNSAFE_END JVM_END
  69 
  70 
  71 static inline void* addr_from_java(jlong addr) {
  72   // This assert fails in a variety of ways on 32-bit systems.
  73   // It is impossible to predict whether native code that converts
  74   // pointers to longs will sign-extend or zero-extend the addresses.
  75   //assert(addr == (uintptr_t)addr, "must not be odd high bits");
  76   return (void*)(uintptr_t)addr;
  77 }
  78 
  79 static inline jlong addr_to_java(void* p) {
  80   assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
  81   return (uintptr_t)p;
  82 }
  83 
  84 
  85 // Note: The VM's obj_field and related accessors use byte-scaled
  86 // ("unscaled") offsets, just as the unsafe methods do.
  87 
  88 // However, the method Unsafe.fieldOffset explicitly declines to
  89 // guarantee this.  The field offset values manipulated by the Java user
  90 // through the Unsafe API are opaque cookies that just happen to be byte
  91 // offsets.  We represent this state of affairs by passing the cookies
  92 // through conversion functions when going between the VM and the Unsafe API.
  93 // The conversion functions just happen to be no-ops at present.
  94 
  95 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
  96   return field_offset;
  97 }
  98 
  99 static inline jlong field_offset_from_byte_offset(jlong byte_offset) {
 100   return byte_offset;
 101 }
 102 
 103 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
 104   jlong byte_offset = field_offset_to_byte_offset(field_offset);
 105 
 106 #ifdef ASSERT
 107   if (p != NULL) {
 108     assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
 109     if (byte_offset == (jint)byte_offset) {
 110       void* ptr_plus_disp = (address)p + byte_offset;
 111       assert((void*)p->obj_field_addr<oop>((jint)byte_offset) == ptr_plus_disp,
 112              "raw [ptr+disp] must be consistent with oop::field_base");
 113     }
 114     jlong p_size = HeapWordSize * (jlong)(p->size());
 115     assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size);
 116   }
 117 #endif
 118 
 119   if (sizeof(char*) == sizeof(jint)) {   // (this constant folds!)
 120     return (address)p + (jint) byte_offset;
 121   } else {
 122     return (address)p +        byte_offset;
 123   }
 124 }
 125 
 126 // Externally callable versions:
 127 // (Use these in compiler intrinsics which emulate unsafe primitives.)
 128 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
 129   return field_offset;
 130 }
 131 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
 132   return byte_offset;
 133 }
 134 
 135 
 136 ///// Data read/writes on the Java heap and in native (off-heap) memory
 137 
 138 /**
 139  * Helper class for accessing memory.
 140  *
 141  * Normalizes values and wraps accesses in
 142  * JavaThread::doing_unsafe_access() if needed.
 143  */
 144 class MemoryAccess : StackObj {
 145   JavaThread* _thread;
 146   jobject _obj;
 147   jlong _offset;
 148 
 149   // Resolves and returns the address of the memory access
 150   void* addr() {
 151     return index_oop_from_field_offset_long(JNIHandles::resolve(_obj), _offset);
 152   }
 153 
 154   template <typename T>
 155   T normalize_for_write(T x) {
 156     return x;
 157   }
 158 
 159   jboolean normalize_for_write(jboolean x) {
 160     return x & 1;
 161   }
 162 
 163   template <typename T>
 164   T normalize_for_read(T x) {
 165     return x;
 166   }
 167 
 168   jboolean normalize_for_read(jboolean x) {
 169     return x != 0;
 170   }
 171 
 172   /**
 173    * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
 174    */
 175   class GuardUnsafeAccess {
 176     JavaThread* _thread;
 177     bool _active;
 178 
 179   public:
 180     GuardUnsafeAccess(JavaThread* thread, jobject _obj) : _thread(thread) {
 181       if (JNIHandles::resolve(_obj) == NULL) {
 182         // native/off-heap access which may raise SIGBUS if accessing
 183         // memory mapped file data in a region of the file which has
 184         // been truncated and is now invalid
 185         _thread->set_doing_unsafe_access(true);
 186         _active = true;
 187       } else {
 188         _active = false;
 189       }
 190     }
 191 
 192     ~GuardUnsafeAccess() {
 193       if (_active) {
 194         _thread->set_doing_unsafe_access(false);
 195       }
 196     }
 197   };
 198 
 199 public:
 200   MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
 201     : _thread(thread), _obj(obj), _offset(offset) {
 202   }
 203 
 204   template <typename T>
 205   T get() {
 206     GuardUnsafeAccess guard(_thread, _obj);
 207 
 208     T* p = (T*)addr();
 209 
 210     T x = normalize_for_read(*p);
 211 
 212     return x;
 213   }
 214 
 215   template <typename T>
 216   void put(T x) {
 217     GuardUnsafeAccess guard(_thread, _obj);
 218 
 219     T* p = (T*)addr();
 220 
 221     *p = normalize_for_write(x);
 222   }
 223 
 224 
 225   template <typename T>
 226   T get_volatile() {
 227     GuardUnsafeAccess guard(_thread, _obj);
 228 
 229     T* p = (T*)addr();
 230 
 231     if (support_IRIW_for_not_multiple_copy_atomic_cpu) {
 232       OrderAccess::fence();
 233     }
 234 
 235     T x = OrderAccess::load_acquire((volatile T*)p);
 236 
 237     return normalize_for_read(x);
 238   }
 239 
 240   template <typename T>
 241   void put_volatile(T x) {
 242     GuardUnsafeAccess guard(_thread, _obj);
 243 
 244     T* p = (T*)addr();
 245 
 246     OrderAccess::release_store_fence((volatile T*)p, normalize_for_write(x));
 247   }
 248 
 249 
 250 #ifndef SUPPORTS_NATIVE_CX8
 251   jlong get_jlong_locked() {
 252     GuardUnsafeAccess guard(_thread, _obj);
 253 
 254     MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
 255 
 256     jlong* p = (jlong*)addr();
 257 
 258     jlong x = Atomic::load(p);
 259 
 260     return x;
 261   }
 262 
 263   void put_jlong_locked(jlong x) {
 264     GuardUnsafeAccess guard(_thread, _obj);
 265 
 266     MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
 267 
 268     jlong* p = (jlong*)addr();
 269 
 270     Atomic::store(normalize_for_write(x),  p);
 271   }
 272 #endif
 273 };
 274 
 275 // Get/PutObject must be special-cased, since it works with handles.
 276 
 277 // We could be accessing the referent field in a reference
 278 // object. If G1 is enabled then we need to register non-null
 279 // referent with the SATB barrier.
 280 
 281 #if INCLUDE_ALL_GCS
 282 static bool is_java_lang_ref_Reference_access(oop o, jlong offset) {
 283   if (offset == java_lang_ref_Reference::referent_offset && o != NULL) {
 284     Klass* k = o->klass();
 285     if (InstanceKlass::cast(k)->reference_type() != REF_NONE) {
 286       assert(InstanceKlass::cast(k)->is_subclass_of(SystemDictionary::Reference_klass()), "sanity");
 287       return true;
 288     }
 289   }
 290   return false;
 291 }
 292 #endif
 293 
 294 static void ensure_satb_referent_alive(oop o, jlong offset, oop v) {
 295 #if INCLUDE_ALL_GCS
 296   if (UseG1GC && v != NULL && is_java_lang_ref_Reference_access(o, offset)) {
 297     G1SATBCardTableModRefBS::enqueue(v);
 298   }
 299 #endif
 300 }
 301 
 302 // These functions allow a null base pointer with an arbitrary address.
 303 // But if the base pointer is non-null, the offset should make some sense.
 304 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
 305 UNSAFE_ENTRY(jobject, Unsafe_GetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
 306   oop p = JNIHandles::resolve(obj);
 307   oop v;
 308 
 309   if (UseCompressedOops) {
 310     narrowOop n = *(narrowOop*)index_oop_from_field_offset_long(p, offset);
 311     v = oopDesc::decode_heap_oop(n);
 312   } else {
 313     v = *(oop*)index_oop_from_field_offset_long(p, offset);
 314   }
 315 
 316   ensure_satb_referent_alive(p, offset, v);
 317 
 318   return JNIHandles::make_local(env, v);
 319 } UNSAFE_END
 320 
 321 UNSAFE_ENTRY(void, Unsafe_PutObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
 322   oop x = JNIHandles::resolve(x_h);
 323   oop p = JNIHandles::resolve(obj);
 324 
 325   if (UseCompressedOops) {
 326     oop_store((narrowOop*)index_oop_from_field_offset_long(p, offset), x);
 327   } else {
 328     oop_store((oop*)index_oop_from_field_offset_long(p, offset), x);
 329   }
 330 } UNSAFE_END
 331 
 332 UNSAFE_ENTRY(jobject, Unsafe_GetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
 333   oop p = JNIHandles::resolve(obj);
 334   void* addr = index_oop_from_field_offset_long(p, offset);
 335 
 336   volatile oop v;
 337 
 338   if (support_IRIW_for_not_multiple_copy_atomic_cpu) {
 339     OrderAccess::fence();
 340   }
 341 
 342   if (UseCompressedOops) {
 343     volatile narrowOop n = *(volatile narrowOop*) addr;
 344     (void)const_cast<oop&>(v = oopDesc::decode_heap_oop(n));
 345   } else {
 346     (void)const_cast<oop&>(v = *(volatile oop*) addr);
 347   }
 348 
 349   ensure_satb_referent_alive(p, offset, v);
 350 
 351   OrderAccess::acquire();
 352   return JNIHandles::make_local(env, v);
 353 } UNSAFE_END
 354 
 355 UNSAFE_ENTRY(void, Unsafe_PutObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
 356   oop x = JNIHandles::resolve(x_h);
 357   oop p = JNIHandles::resolve(obj);
 358   void* addr = index_oop_from_field_offset_long(p, offset);
 359   OrderAccess::release();
 360 
 361   if (UseCompressedOops) {
 362     oop_store((narrowOop*)addr, x);
 363   } else {
 364     oop_store((oop*)addr, x);
 365   }
 366 
 367   OrderAccess::fence();
 368 } UNSAFE_END
 369 
 370 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
 371   oop v = *(oop*) (address) addr;
 372 
 373   return JNIHandles::make_local(env, v);
 374 } UNSAFE_END
 375 
 376 #ifndef SUPPORTS_NATIVE_CX8
 377 
 378 // VM_Version::supports_cx8() is a surrogate for 'supports atomic long memory ops'.
 379 //
 380 // On platforms which do not support atomic compare-and-swap of jlong (8 byte)
 381 // values we have to use a lock-based scheme to enforce atomicity. This has to be
 382 // applied to all Unsafe operations that set the value of a jlong field. Even so
 383 // the compareAndSetLong operation will not be atomic with respect to direct stores
 384 // to the field from Java code. It is important therefore that any Java code that
 385 // utilizes these Unsafe jlong operations does not perform direct stores. To permit
 386 // direct loads of the field from Java code we must also use Atomic::store within the
 387 // locked regions. And for good measure, in case there are direct stores, we also
 388 // employ Atomic::load within those regions. Note that the field in question must be
 389 // volatile and so must have atomic load/store accesses applied at the Java level.
 390 //
 391 // The locking scheme could utilize a range of strategies for controlling the locking
 392 // granularity: from a lock per-field through to a single global lock. The latter is
 393 // the simplest and is used for the current implementation. Note that the Java object
 394 // that contains the field, can not, in general, be used for locking. To do so can lead
 395 // to deadlocks as we may introduce locking into what appears to the Java code to be a
 396 // lock-free path.
 397 //
 398 // As all the locked-regions are very short and themselves non-blocking we can treat
 399 // them as leaf routines and elide safepoint checks (ie we don't perform any thread
 400 // state transitions even when blocking for the lock). Note that if we do choose to
 401 // add safepoint checks and thread state transitions, we must ensure that we calculate
 402 // the address of the field _after_ we have acquired the lock, else the object may have
 403 // been moved by the GC
 404 
 405 UNSAFE_ENTRY(jlong, Unsafe_GetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
 406   if (VM_Version::supports_cx8()) {
 407     return MemoryAccess(thread, obj, offset).get_volatile<jlong>();
 408   } else {
 409     return MemoryAccess(thread, obj, offset).get_jlong_locked();
 410   }
 411 } UNSAFE_END
 412 
 413 UNSAFE_ENTRY(void, Unsafe_PutLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x)) {
 414   if (VM_Version::supports_cx8()) {
 415     MemoryAccess(thread, obj, offset).put_volatile<jlong>(x);
 416   } else {
 417     MemoryAccess(thread, obj, offset).put_jlong_locked(x);
 418   }
 419 } UNSAFE_END
 420 
 421 #endif // not SUPPORTS_NATIVE_CX8
 422 
 423 UNSAFE_LEAF(jboolean, Unsafe_isBigEndian0(JNIEnv *env, jobject unsafe)) {
 424 #ifdef VM_LITTLE_ENDIAN
 425   return false;
 426 #else
 427   return true;
 428 #endif
 429 } UNSAFE_END
 430 
 431 UNSAFE_LEAF(jint, Unsafe_unalignedAccess0(JNIEnv *env, jobject unsafe)) {
 432   return UseUnalignedAccesses;
 433 } UNSAFE_END
 434 
 435 #define DEFINE_GETSETOOP(java_type, Type) \
 436  \
 437 UNSAFE_ENTRY(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
 438   return MemoryAccess(thread, obj, offset).get<java_type>(); \
 439 } UNSAFE_END \
 440  \
 441 UNSAFE_ENTRY(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
 442   MemoryAccess(thread, obj, offset).put<java_type>(x); \
 443 } UNSAFE_END \
 444  \
 445 // END DEFINE_GETSETOOP.
 446 
 447 DEFINE_GETSETOOP(jboolean, Boolean)
 448 DEFINE_GETSETOOP(jbyte, Byte)
 449 DEFINE_GETSETOOP(jshort, Short);
 450 DEFINE_GETSETOOP(jchar, Char);
 451 DEFINE_GETSETOOP(jint, Int);
 452 DEFINE_GETSETOOP(jlong, Long);
 453 DEFINE_GETSETOOP(jfloat, Float);
 454 DEFINE_GETSETOOP(jdouble, Double);
 455 
 456 #undef DEFINE_GETSETOOP
 457 
 458 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
 459  \
 460 UNSAFE_ENTRY(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
 461   return MemoryAccess(thread, obj, offset).get_volatile<java_type>(); \
 462 } UNSAFE_END \
 463  \
 464 UNSAFE_ENTRY(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
 465   MemoryAccess(thread, obj, offset).put_volatile<java_type>(x); \
 466 } UNSAFE_END \
 467  \
 468 // END DEFINE_GETSETOOP_VOLATILE.
 469 
 470 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
 471 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
 472 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
 473 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
 474 DEFINE_GETSETOOP_VOLATILE(jint, Int);
 475 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
 476 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
 477 
 478 #ifdef SUPPORTS_NATIVE_CX8
 479 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
 480 #endif
 481 
 482 #undef DEFINE_GETSETOOP_VOLATILE
 483 
 484 UNSAFE_LEAF(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe)) {
 485   OrderAccess::acquire();
 486 } UNSAFE_END
 487 
 488 UNSAFE_LEAF(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe)) {
 489   OrderAccess::release();
 490 } UNSAFE_END
 491 
 492 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
 493   OrderAccess::fence();
 494 } UNSAFE_END
 495 
 496 ////// Allocation requests
 497 
 498 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
 499   ThreadToNativeFromVM ttnfv(thread);
 500   return env->AllocObject(cls);
 501 } UNSAFE_END
 502 
 503 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
 504   size_t sz = (size_t)size;
 505 
 506   sz = align_up(sz, HeapWordSize);
 507   void* x = os::malloc(sz, mtInternal);
 508 
 509   return addr_to_java(x);
 510 } UNSAFE_END
 511 
 512 UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) {
 513   void* p = addr_from_java(addr);
 514   size_t sz = (size_t)size;
 515   sz = align_up(sz, HeapWordSize);
 516 
 517   void* x = os::realloc(p, sz, mtInternal);
 518 
 519   return addr_to_java(x);
 520 } UNSAFE_END
 521 
 522 UNSAFE_ENTRY(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
 523   void* p = addr_from_java(addr);
 524 
 525   os::free(p);
 526 } UNSAFE_END
 527 
 528 UNSAFE_ENTRY(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
 529   size_t sz = (size_t)size;
 530 
 531   oop base = JNIHandles::resolve(obj);
 532   void* p = index_oop_from_field_offset_long(base, offset);
 533 
 534   Copy::fill_to_memory_atomic(p, sz, value);
 535 } UNSAFE_END
 536 
 537 UNSAFE_ENTRY(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
 538   size_t sz = (size_t)size;
 539 
 540   oop srcp = JNIHandles::resolve(srcObj);
 541   oop dstp = JNIHandles::resolve(dstObj);
 542 
 543   void* src = index_oop_from_field_offset_long(srcp, srcOffset);
 544   void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
 545 
 546   Copy::conjoint_memory_atomic(src, dst, sz);
 547 } UNSAFE_END
 548 
 549 // This function is a leaf since if the source and destination are both in native memory
 550 // the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
 551 // If either source or destination (or both) are on the heap, the function will enter VM using
 552 // JVM_ENTRY_FROM_LEAF
 553 UNSAFE_LEAF(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
 554   size_t sz = (size_t)size;
 555   size_t esz = (size_t)elemSize;
 556 
 557   if (srcObj == NULL && dstObj == NULL) {
 558     // Both src & dst are in native memory
 559     address src = (address)srcOffset;
 560     address dst = (address)dstOffset;
 561 
 562     Copy::conjoint_swap(src, dst, sz, esz);
 563   } else {
 564     // At least one of src/dst are on heap, transition to VM to access raw pointers
 565 
 566     JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory0) {
 567       oop srcp = JNIHandles::resolve(srcObj);
 568       oop dstp = JNIHandles::resolve(dstObj);
 569 
 570       address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
 571       address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
 572 
 573       Copy::conjoint_swap(src, dst, sz, esz);
 574     } JVM_END
 575   }
 576 } UNSAFE_END
 577 
 578 ////// Random queries
 579 
 580 UNSAFE_LEAF(jint, Unsafe_AddressSize0(JNIEnv *env, jobject unsafe)) {
 581   return sizeof(void*);
 582 } UNSAFE_END
 583 
 584 UNSAFE_LEAF(jint, Unsafe_PageSize()) {
 585   return os::vm_page_size();
 586 } UNSAFE_END
 587 
 588 static jlong find_field_offset(jclass clazz, jstring name, TRAPS) {
 589   assert(clazz != NULL, "clazz must not be NULL");
 590   assert(name != NULL, "name must not be NULL");
 591 
 592   ResourceMark rm(THREAD);
 593   char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
 594 
 595   InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz)));
 596 
 597   jint offset = -1;
 598   for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
 599     Symbol *name = fs.name();
 600     if (name->equals(utf_name)) {
 601       offset = fs.offset();
 602       break;
 603     }
 604   }
 605   if (offset < 0) {
 606     THROW_0(vmSymbols::java_lang_InternalError());
 607   }
 608   return field_offset_from_byte_offset(offset);
 609 }
 610 
 611 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
 612   assert(field != NULL, "field must not be NULL");
 613 
 614   oop reflected   = JNIHandles::resolve_non_null(field);
 615   oop mirror      = java_lang_reflect_Field::clazz(reflected);
 616   Klass* k        = java_lang_Class::as_Klass(mirror);
 617   int slot        = java_lang_reflect_Field::slot(reflected);
 618   int modifiers   = java_lang_reflect_Field::modifiers(reflected);
 619 
 620   if (must_be_static >= 0) {
 621     int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
 622     if (must_be_static != really_is_static) {
 623       THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 624     }
 625   }
 626 
 627   int offset = InstanceKlass::cast(k)->field_offset(slot);
 628   return field_offset_from_byte_offset(offset);
 629 }
 630 
 631 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
 632   return find_field_offset(field, 0, THREAD);
 633 } UNSAFE_END
 634 
 635 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset1(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
 636   return find_field_offset(c, name, THREAD);
 637 } UNSAFE_END
 638 
 639 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
 640   return find_field_offset(field, 1, THREAD);
 641 } UNSAFE_END
 642 
 643 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
 644   assert(field != NULL, "field must not be NULL");
 645 
 646   // Note:  In this VM implementation, a field address is always a short
 647   // offset from the base of a a klass metaobject.  Thus, the full dynamic
 648   // range of the return type is never used.  However, some implementations
 649   // might put the static field inside an array shared by many classes,
 650   // or even at a fixed address, in which case the address could be quite
 651   // large.  In that last case, this function would return NULL, since
 652   // the address would operate alone, without any base pointer.
 653 
 654   oop reflected   = JNIHandles::resolve_non_null(field);
 655   oop mirror      = java_lang_reflect_Field::clazz(reflected);
 656   int modifiers   = java_lang_reflect_Field::modifiers(reflected);
 657 
 658   if ((modifiers & JVM_ACC_STATIC) == 0) {
 659     THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 660   }
 661 
 662   return JNIHandles::make_local(env, mirror);
 663 } UNSAFE_END
 664 
 665 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
 666   assert(clazz != NULL, "clazz must not be NULL");
 667 
 668   oop mirror = JNIHandles::resolve_non_null(clazz);
 669 
 670   Klass* klass = java_lang_Class::as_Klass(mirror);
 671   if (klass != NULL && klass->should_be_initialized()) {
 672     InstanceKlass* k = InstanceKlass::cast(klass);
 673     k->initialize(CHECK);
 674   }
 675 }
 676 UNSAFE_END
 677 
 678 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
 679   assert(clazz != NULL, "clazz must not be NULL");
 680 
 681   oop mirror = JNIHandles::resolve_non_null(clazz);
 682   Klass* klass = java_lang_Class::as_Klass(mirror);
 683 
 684   if (klass != NULL && klass->should_be_initialized()) {
 685     return true;
 686   }
 687 
 688   return false;
 689 }
 690 UNSAFE_END
 691 
 692 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
 693   assert(clazz != NULL, "clazz must not be NULL");
 694 
 695   oop mirror = JNIHandles::resolve_non_null(clazz);
 696   Klass* k = java_lang_Class::as_Klass(mirror);
 697 
 698   if (k == NULL || !k->is_array_klass()) {
 699     THROW(vmSymbols::java_lang_InvalidClassException());
 700   } else if (k->is_objArray_klass()) {
 701     base  = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
 702     scale = heapOopSize;
 703   } else if (k->is_typeArray_klass()) {
 704     TypeArrayKlass* tak = TypeArrayKlass::cast(k);
 705     base  = tak->array_header_in_bytes();
 706     assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
 707     scale = (1 << tak->log2_element_size());
 708   } else {
 709     ShouldNotReachHere();
 710   }
 711 }
 712 
 713 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
 714   int base = 0, scale = 0;
 715   getBaseAndScale(base, scale, clazz, CHECK_0);
 716 
 717   return field_offset_from_byte_offset(base);
 718 } UNSAFE_END
 719 
 720 
 721 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
 722   int base = 0, scale = 0;
 723   getBaseAndScale(base, scale, clazz, CHECK_0);
 724 
 725   // This VM packs both fields and array elements down to the byte.
 726   // But watch out:  If this changes, so that array references for
 727   // a given primitive type (say, T_BOOLEAN) use different memory units
 728   // than fields, this method MUST return zero for such arrays.
 729   // For example, the VM used to store sub-word sized fields in full
 730   // words in the object layout, so that accessors like getByte(Object,int)
 731   // did not really do what one might expect for arrays.  Therefore,
 732   // this function used to report a zero scale factor, so that the user
 733   // would know not to attempt to access sub-word array elements.
 734   // // Code for unpacked fields:
 735   // if (scale < wordSize)  return 0;
 736 
 737   // The following allows for a pretty general fieldOffset cookie scheme,
 738   // but requires it to be linear in byte offset.
 739   return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
 740 } UNSAFE_END
 741 
 742 
 743 static inline void throw_new(JNIEnv *env, const char *ename) {
 744   jclass cls = env->FindClass(ename);
 745   if (env->ExceptionCheck()) {
 746     env->ExceptionClear();
 747     tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
 748     return;
 749   }
 750 
 751   env->ThrowNew(cls, NULL);
 752 }
 753 
 754 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
 755   // Code lifted from JDK 1.3 ClassLoader.c
 756 
 757   jbyte *body;
 758   char *utfName = NULL;
 759   jclass result = 0;
 760   char buf[128];
 761 
 762   assert(data != NULL, "Class bytes must not be NULL");
 763   assert(length >= 0, "length must not be negative: %d", length);
 764 
 765   if (UsePerfData) {
 766     ClassLoader::unsafe_defineClassCallCounter()->inc();
 767   }
 768 
 769   body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
 770   if (body == NULL) {
 771     throw_new(env, "java/lang/OutOfMemoryError");
 772     return 0;
 773   }
 774 
 775   env->GetByteArrayRegion(data, offset, length, body);
 776   if (env->ExceptionOccurred()) {
 777     goto free_body;
 778   }
 779 
 780   if (name != NULL) {
 781     uint len = env->GetStringUTFLength(name);
 782     int unicode_len = env->GetStringLength(name);
 783 
 784     if (len >= sizeof(buf)) {
 785       utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
 786       if (utfName == NULL) {
 787         throw_new(env, "java/lang/OutOfMemoryError");
 788         goto free_body;
 789       }
 790     } else {
 791       utfName = buf;
 792     }
 793 
 794     env->GetStringUTFRegion(name, 0, unicode_len, utfName);
 795 
 796     for (uint i = 0; i < len; i++) {
 797       if (utfName[i] == '.')   utfName[i] = '/';
 798     }
 799   }
 800 
 801   result = JVM_DefineClass(env, utfName, loader, body, length, pd);
 802 
 803   if (utfName && utfName != buf) {
 804     FREE_C_HEAP_ARRAY(char, utfName);
 805   }
 806 
 807  free_body:
 808   FREE_C_HEAP_ARRAY(jbyte, body);
 809   return result;
 810 }
 811 
 812 
 813 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
 814   ThreadToNativeFromVM ttnfv(thread);
 815 
 816   return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
 817 } UNSAFE_END
 818 
 819 
 820 // define a class but do not make it known to the class loader or system dictionary
 821 // - host_class:  supplies context for linkage, access control, protection domain, and class loader
 822 //                if host_class is itself anonymous then it is replaced with its host class.
 823 // - data:  bytes of a class file, a raw memory address (length gives the number of bytes)
 824 // - cp_patches:  where non-null entries exist, they replace corresponding CP entries in data
 825 
 826 // When you load an anonymous class U, it works as if you changed its name just before loading,
 827 // to a name that you will never use again.  Since the name is lost, no other class can directly
 828 // link to any member of U.  Just after U is loaded, the only way to use it is reflectively,
 829 // through java.lang.Class methods like Class.newInstance.
 830 
 831 // The package of an anonymous class must either match its host's class's package or be in the
 832 // unnamed package.  If it is in the unnamed package then it will be put in its host class's
 833 // package.
 834 //
 835 
 836 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
 837 // An anonymous class also has special privileges to access any member of its host class.
 838 // This is the main reason why this loading operation is unsafe.  The purpose of this is to
 839 // allow language implementations to simulate "open classes"; a host class in effect gets
 840 // new code when an anonymous class is loaded alongside it.  A less convenient but more
 841 // standard way to do this is with reflection, which can also be set to ignore access
 842 // restrictions.
 843 
 844 // Access into an anonymous class is possible only through reflection.  Therefore, there
 845 // are no special access rules for calling into an anonymous class.  The relaxed access
 846 // rule for the host class is applied in the opposite direction:  A host class reflectively
 847 // access one of its anonymous classes.
 848 
 849 // If you load the same bytecodes twice, you get two different classes.  You can reload
 850 // the same bytecodes with or without varying CP patches.
 851 
 852 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
 853 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
 854 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
 855 
 856 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
 857 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
 858 // It is not possible for a named class, or an older anonymous class, to refer by
 859 // name (via its CP) to a newer anonymous class.
 860 
 861 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
 862 // or type descriptors used in the loaded anonymous class.
 863 
 864 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
 865 // instead of "dead" strings.  A compiled statement like println((Object)"hello") can
 866 // be changed to println(greeting), where greeting is an arbitrary object created before
 867 // the anonymous class is loaded.  This is useful in dynamic languages, in which
 868 // various kinds of metaobjects must be introduced as constants into bytecode.
 869 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
 870 // not just a literal string.  For such ldc instructions, the verifier uses the
 871 // type Object instead of String, if the loaded constant is not in fact a String.
 872 
 873 static InstanceKlass*
 874 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
 875                                  jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
 876                                  u1** temp_alloc,
 877                                  TRAPS) {
 878   assert(host_class != NULL, "host_class must not be NULL");
 879   assert(data != NULL, "data must not be NULL");
 880 
 881   if (UsePerfData) {
 882     ClassLoader::unsafe_defineClassCallCounter()->inc();
 883   }
 884 
 885   jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
 886   assert(length >= 0, "class_bytes_length must not be negative: %d", length);
 887 
 888   int class_bytes_length = (int) length;
 889 
 890   u1* class_bytes = NEW_C_HEAP_ARRAY(u1, length, mtInternal);
 891   if (class_bytes == NULL) {
 892     THROW_0(vmSymbols::java_lang_OutOfMemoryError());
 893   }
 894 
 895   // caller responsible to free it:
 896   *temp_alloc = class_bytes;
 897 
 898   jbyte* array_base = typeArrayOop(JNIHandles::resolve_non_null(data))->byte_at_addr(0);
 899   Copy::conjoint_jbytes(array_base, class_bytes, length);
 900 
 901   objArrayHandle cp_patches_h;
 902   if (cp_patches_jh != NULL) {
 903     oop p = JNIHandles::resolve_non_null(cp_patches_jh);
 904     assert(p->is_objArray(), "cp_patches must be an object[]");
 905     cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
 906   }
 907 
 908   const Klass* host_klass = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class));
 909 
 910   // Make sure it's the real host class, not another anonymous class.
 911   while (host_klass != NULL && host_klass->is_instance_klass() &&
 912          InstanceKlass::cast(host_klass)->is_anonymous()) {
 913     host_klass = InstanceKlass::cast(host_klass)->host_klass();
 914   }
 915 
 916   // Primitive types have NULL Klass* fields in their java.lang.Class instances.
 917   if (host_klass == NULL) {
 918     THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), "Host class is null");
 919   }
 920 
 921   assert(host_klass->is_instance_klass(), "Host class must be an instance class");
 922 
 923   const char* host_source = host_klass->external_name();
 924   Handle      host_loader(THREAD, host_klass->class_loader());
 925   Handle      host_domain(THREAD, host_klass->protection_domain());
 926 
 927   GrowableArray<Handle>* cp_patches = NULL;
 928 
 929   if (cp_patches_h.not_null()) {
 930     int alen = cp_patches_h->length();
 931 
 932     for (int i = alen-1; i >= 0; i--) {
 933       oop p = cp_patches_h->obj_at(i);
 934       if (p != NULL) {
 935         Handle patch(THREAD, p);
 936 
 937         if (cp_patches == NULL) {
 938           cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
 939         }
 940 
 941         cp_patches->at_put(i, patch);
 942       }
 943     }
 944   }
 945 
 946   ClassFileStream st(class_bytes, class_bytes_length, host_source, ClassFileStream::verify);
 947 
 948   Symbol* no_class_name = NULL;
 949   Klass* anonk = SystemDictionary::parse_stream(no_class_name,
 950                                                 host_loader,
 951                                                 host_domain,
 952                                                 &st,
 953                                                 InstanceKlass::cast(host_klass),
 954                                                 cp_patches,
 955                                                 CHECK_NULL);
 956   if (anonk == NULL) {
 957     return NULL;
 958   }
 959 
 960   return InstanceKlass::cast(anonk);
 961 }
 962 
 963 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass0(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh)) {
 964   ResourceMark rm(THREAD);
 965 
 966   jobject res_jh = NULL;
 967   u1* temp_alloc = NULL;
 968 
 969   InstanceKlass* anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data, cp_patches_jh, &temp_alloc, THREAD);
 970   if (anon_klass != NULL) {
 971     res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
 972   }
 973 
 974   // try/finally clause:
 975   if (temp_alloc != NULL) {
 976     FREE_C_HEAP_ARRAY(u1, temp_alloc);
 977   }
 978 
 979   // The anonymous class loader data has been artificially been kept alive to
 980   // this point.   The mirror and any instances of this class have to keep
 981   // it alive afterwards.
 982   if (anon_klass != NULL) {
 983     anon_klass->class_loader_data()->dec_keep_alive();
 984   }
 985 
 986   // let caller initialize it as needed...
 987 
 988   return (jclass) res_jh;
 989 } UNSAFE_END
 990 
 991 
 992 
 993 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
 994   ThreadToNativeFromVM ttnfv(thread);
 995   env->Throw(thr);
 996 } UNSAFE_END
 997 
 998 // JSR166 ------------------------------------------------------------------
 999 
1000 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1001   oop x = JNIHandles::resolve(x_h);
1002   oop e = JNIHandles::resolve(e_h);
1003   oop p = JNIHandles::resolve(obj);
1004   HeapWord* addr = (HeapWord *)index_oop_from_field_offset_long(p, offset);
1005   oop res = oopDesc::atomic_compare_exchange_oop(x, addr, e, true);
1006   if (res == e) {
1007     update_barrier_set((void*)addr, x);
1008   }
1009   return JNIHandles::make_local(env, res);
1010 } UNSAFE_END
1011 
1012 UNSAFE_ENTRY(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1013   oop p = JNIHandles::resolve(obj);
1014   jint* addr = (jint *) index_oop_from_field_offset_long(p, offset);
1015 
1016   return (jint)(Atomic::cmpxchg(x, addr, e));
1017 } UNSAFE_END
1018 
1019 UNSAFE_ENTRY(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1020   Handle p(THREAD, JNIHandles::resolve(obj));
1021   jlong* addr = (jlong*)index_oop_from_field_offset_long(p(), offset);
1022 
1023 #ifdef SUPPORTS_NATIVE_CX8
1024   return (jlong)(Atomic::cmpxchg(x, addr, e));
1025 #else
1026   if (VM_Version::supports_cx8()) {
1027     return (jlong)(Atomic::cmpxchg(x, addr, e));
1028   } else {
1029     MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
1030 
1031     jlong val = Atomic::load(addr);
1032     if (val == e) {
1033       Atomic::store(x, addr);
1034     }
1035     return val;
1036   }
1037 #endif
1038 } UNSAFE_END
1039 
1040 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1041   oop x = JNIHandles::resolve(x_h);
1042   oop e = JNIHandles::resolve(e_h);
1043   oop p = JNIHandles::resolve(obj);
1044   HeapWord* addr = (HeapWord *)index_oop_from_field_offset_long(p, offset);
1045   oop res = oopDesc::atomic_compare_exchange_oop(x, addr, e, true);
1046   if (res != e) {
1047     return false;
1048   }
1049 
1050   update_barrier_set((void*)addr, x);
1051 
1052   return true;
1053 } UNSAFE_END
1054 
1055 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1056   oop p = JNIHandles::resolve(obj);
1057   jint* addr = (jint *)index_oop_from_field_offset_long(p, offset);
1058 
1059   return (jint)(Atomic::cmpxchg(x, addr, e)) == e;
1060 } UNSAFE_END
1061 
1062 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1063   Handle p(THREAD, JNIHandles::resolve(obj));
1064   jlong* addr = (jlong*)index_oop_from_field_offset_long(p(), offset);
1065 
1066 #ifdef SUPPORTS_NATIVE_CX8
1067   return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1068 #else
1069   if (VM_Version::supports_cx8()) {
1070     return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1071   } else {
1072     MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
1073 
1074     jlong val = Atomic::load(addr);
1075     if (val != e) {
1076       return false;
1077     }
1078 
1079     Atomic::store(x, addr);
1080     return true;
1081   }
1082 #endif
1083 } UNSAFE_END
1084 
1085 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
1086   EventThreadPark event;
1087   HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1088 
1089   JavaThreadParkedState jtps(thread, time != 0);
1090   thread->parker()->park(isAbsolute != 0, time);
1091 
1092   HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1093 
1094   if (event.should_commit()) {
1095     oop obj = thread->current_park_blocker();
1096     event.set_parkedClass((obj != NULL) ? obj->klass() : NULL);
1097     event.set_timeout(time);
1098     event.set_address((obj != NULL) ? (TYPE_ADDRESS) cast_from_oop<uintptr_t>(obj) : 0);
1099     event.commit();
1100   }
1101 } UNSAFE_END
1102 
1103 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
1104   Parker* p = NULL;
1105 
1106   if (jthread != NULL) {
1107     oop java_thread = JNIHandles::resolve_non_null(jthread);
1108     if (java_thread != NULL) {
1109       jlong lp = java_lang_Thread::park_event(java_thread);
1110       if (lp != 0) {
1111         // This cast is OK even though the jlong might have been read
1112         // non-atomically on 32bit systems, since there, one word will
1113         // always be zero anyway and the value set is always the same
1114         p = (Parker*)addr_from_java(lp);
1115       } else {
1116         // Grab lock if apparently null or using older version of library
1117         MutexLocker mu(Threads_lock);
1118         java_thread = JNIHandles::resolve_non_null(jthread);
1119 
1120         if (java_thread != NULL) {
1121           JavaThread* thr = java_lang_Thread::thread(java_thread);
1122           if (thr != NULL) {
1123             p = thr->parker();
1124             if (p != NULL) { // Bind to Java thread for next time.
1125               java_lang_Thread::set_park_event(java_thread, addr_to_java(p));
1126             }
1127           }
1128         }
1129       }
1130     }
1131   }
1132 
1133   if (p != NULL) {
1134     HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1135     p->unpark();
1136   }
1137 } UNSAFE_END
1138 
1139 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
1140   const int max_nelem = 3;
1141   double la[max_nelem];
1142   jint ret;
1143 
1144   typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1145   assert(a->is_typeArray(), "must be type array");
1146 
1147   ret = os::loadavg(la, nelem);
1148   if (ret == -1) {
1149     return -1;
1150   }
1151 
1152   // if successful, ret is the number of samples actually retrieved.
1153   assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1154   switch(ret) {
1155     case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1156     case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1157     case 1: a->double_at_put(0, (jdouble)la[0]); break;
1158   }
1159 
1160   return ret;
1161 } UNSAFE_END
1162 
1163 
1164 /// JVM_RegisterUnsafeMethods
1165 
1166 #define ADR "J"
1167 
1168 #define LANG "Ljava/lang/"
1169 
1170 #define OBJ LANG "Object;"
1171 #define CLS LANG "Class;"
1172 #define FLD LANG "reflect/Field;"
1173 #define THR LANG "Throwable;"
1174 
1175 #define DC_Args  LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1176 #define DAC_Args CLS "[B[" OBJ
1177 
1178 #define CC (char*)  /*cast a literal from (const char*)*/
1179 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1180 
1181 #define DECLARE_GETPUTOOP(Type, Desc) \
1182     {CC "get" #Type,      CC "(" OBJ "J)" #Desc,       FN_PTR(Unsafe_Get##Type)}, \
1183     {CC "put" #Type,      CC "(" OBJ "J" #Desc ")V",   FN_PTR(Unsafe_Put##Type)}, \
1184     {CC "get" #Type "Volatile",      CC "(" OBJ "J)" #Desc,       FN_PTR(Unsafe_Get##Type##Volatile)}, \
1185     {CC "put" #Type "Volatile",      CC "(" OBJ "J" #Desc ")V",   FN_PTR(Unsafe_Put##Type##Volatile)}
1186 
1187 
1188 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1189     {CC "getObject",        CC "(" OBJ "J)" OBJ "",   FN_PTR(Unsafe_GetObject)},
1190     {CC "putObject",        CC "(" OBJ "J" OBJ ")V",  FN_PTR(Unsafe_PutObject)},
1191     {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "",   FN_PTR(Unsafe_GetObjectVolatile)},
1192     {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V",  FN_PTR(Unsafe_PutObjectVolatile)},
1193 
1194     {CC "getUncompressedObject", CC "(" ADR ")" OBJ,  FN_PTR(Unsafe_GetUncompressedObject)},
1195 
1196     DECLARE_GETPUTOOP(Boolean, Z),
1197     DECLARE_GETPUTOOP(Byte, B),
1198     DECLARE_GETPUTOOP(Short, S),
1199     DECLARE_GETPUTOOP(Char, C),
1200     DECLARE_GETPUTOOP(Int, I),
1201     DECLARE_GETPUTOOP(Long, J),
1202     DECLARE_GETPUTOOP(Float, F),
1203     DECLARE_GETPUTOOP(Double, D),
1204 
1205     {CC "allocateMemory0",    CC "(J)" ADR,              FN_PTR(Unsafe_AllocateMemory0)},
1206     {CC "reallocateMemory0",  CC "(" ADR "J)" ADR,       FN_PTR(Unsafe_ReallocateMemory0)},
1207     {CC "freeMemory0",        CC "(" ADR ")V",           FN_PTR(Unsafe_FreeMemory0)},
1208 
1209     {CC "objectFieldOffset0", CC "(" FLD ")J",           FN_PTR(Unsafe_ObjectFieldOffset0)},
1210     {CC "objectFieldOffset1", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_ObjectFieldOffset1)},
1211     {CC "staticFieldOffset0", CC "(" FLD ")J",           FN_PTR(Unsafe_StaticFieldOffset0)},
1212     {CC "staticFieldBase0",   CC "(" FLD ")" OBJ,        FN_PTR(Unsafe_StaticFieldBase0)},
1213     {CC "ensureClassInitialized0", CC "(" CLS ")V",      FN_PTR(Unsafe_EnsureClassInitialized0)},
1214     {CC "arrayBaseOffset0",   CC "(" CLS ")I",           FN_PTR(Unsafe_ArrayBaseOffset0)},
1215     {CC "arrayIndexScale0",   CC "(" CLS ")I",           FN_PTR(Unsafe_ArrayIndexScale0)},
1216     {CC "addressSize0",       CC "()I",                  FN_PTR(Unsafe_AddressSize0)},
1217     {CC "pageSize",           CC "()I",                  FN_PTR(Unsafe_PageSize)},
1218 
1219     {CC "defineClass0",       CC "(" DC_Args ")" CLS,    FN_PTR(Unsafe_DefineClass0)},
1220     {CC "allocateInstance",   CC "(" CLS ")" OBJ,        FN_PTR(Unsafe_AllocateInstance)},
1221     {CC "throwException",     CC "(" THR ")V",           FN_PTR(Unsafe_ThrowException)},
1222     {CC "compareAndSetObject",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetObject)},
1223     {CC "compareAndSetInt",   CC "(" OBJ "J""I""I"")Z",  FN_PTR(Unsafe_CompareAndSetInt)},
1224     {CC "compareAndSetLong",  CC "(" OBJ "J""J""J"")Z",  FN_PTR(Unsafe_CompareAndSetLong)},
1225     {CC "compareAndExchangeObject", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeObject)},
1226     {CC "compareAndExchangeInt",  CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1227     {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1228 
1229     {CC "park",               CC "(ZJ)V",                FN_PTR(Unsafe_Park)},
1230     {CC "unpark",             CC "(" OBJ ")V",           FN_PTR(Unsafe_Unpark)},
1231 
1232     {CC "getLoadAverage0",    CC "([DI)I",               FN_PTR(Unsafe_GetLoadAverage0)},
1233 
1234     {CC "copyMemory0",        CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1235     {CC "copySwapMemory0",    CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1236     {CC "setMemory0",         CC "(" OBJ "JJB)V",        FN_PTR(Unsafe_SetMemory0)},
1237 
1238     {CC "defineAnonymousClass0", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass0)},
1239 
1240     {CC "shouldBeInitialized0", CC "(" CLS ")Z",         FN_PTR(Unsafe_ShouldBeInitialized0)},
1241 
1242     {CC "loadFence",          CC "()V",                  FN_PTR(Unsafe_LoadFence)},
1243     {CC "storeFence",         CC "()V",                  FN_PTR(Unsafe_StoreFence)},
1244     {CC "fullFence",          CC "()V",                  FN_PTR(Unsafe_FullFence)},
1245 
1246     {CC "isBigEndian0",       CC "()Z",                  FN_PTR(Unsafe_isBigEndian0)},
1247     {CC "unalignedAccess0",   CC "()Z",                  FN_PTR(Unsafe_unalignedAccess0)}
1248 };
1249 
1250 #undef CC
1251 #undef FN_PTR
1252 
1253 #undef ADR
1254 #undef LANG
1255 #undef OBJ
1256 #undef CLS
1257 #undef FLD
1258 #undef THR
1259 #undef DC_Args
1260 #undef DAC_Args
1261 
1262 #undef DECLARE_GETPUTOOP
1263 
1264 
1265 // This function is exported, used by NativeLookup.
1266 // The Unsafe_xxx functions above are called only from the interpreter.
1267 // The optimizer looks at names and signatures to recognize
1268 // individual functions.
1269 
1270 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1271   ThreadToNativeFromVM ttnfv(thread);
1272 
1273   int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1274   guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1275 } JVM_END