1 /*
   2  * Copyright (c) 2000, 2015, 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/vmSymbols.hpp"
  27 #include "memory/allocation.inline.hpp"
  28 #include "oops/objArrayOop.inline.hpp"
  29 #include "oops/oop.inline.hpp"
  30 #include "prims/jni.h"
  31 #include "prims/jvm.h"
  32 #include "runtime/atomic.inline.hpp"
  33 #include "runtime/globals.hpp"
  34 #include "runtime/interfaceSupport.hpp"
  35 #include "runtime/orderAccess.inline.hpp"
  36 #include "runtime/reflection.hpp"
  37 #include "runtime/vm_version.hpp"
  38 #include "services/threadService.hpp"
  39 #include "trace/tracing.hpp"
  40 #include "utilities/copy.hpp"
  41 #include "utilities/dtrace.hpp"
  42 #include "utilities/macros.hpp"
  43 #if INCLUDE_ALL_GCS
  44 #include "gc/g1/g1SATBCardTableModRefBS.hpp"
  45 #endif // INCLUDE_ALL_GCS
  46 
  47 /*
  48  *      Implementation of class sun.misc.Unsafe
  49  */
  50 
  51 
  52 #define MAX_OBJECT_SIZE \
  53   ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
  54     + ((julong)max_jint * sizeof(double)) )
  55 
  56 
  57 #define UNSAFE_ENTRY(result_type, header) \
  58   JVM_ENTRY(result_type, header)
  59 
  60 // Can't use UNSAFE_LEAF because it has the signature of a straight
  61 // call into the runtime (just like JVM_LEAF, funny that) but it's
  62 // called like a Java Native and thus the wrapper built for it passes
  63 // arguments like a JNI call.  It expects those arguments to be popped
  64 // from the stack on Intel like all good JNI args are, and adjusts the
  65 // stack according.  Since the JVM_LEAF call expects no extra
  66 // arguments the stack isn't popped in the C code, is pushed by the
  67 // wrapper and we get sick.
  68 //#define UNSAFE_LEAF(result_type, header) \
  69 //  JVM_LEAF(result_type, header)
  70 
  71 #define UNSAFE_END JVM_END
  72 
  73 #define UnsafeWrapper(arg) /*nothing, for the present*/
  74 
  75 
  76 inline void* addr_from_java(jlong addr) {
  77   // This assert fails in a variety of ways on 32-bit systems.
  78   // It is impossible to predict whether native code that converts
  79   // pointers to longs will sign-extend or zero-extend the addresses.
  80   //assert(addr == (uintptr_t)addr, "must not be odd high bits");
  81   return (void*)(uintptr_t)addr;
  82 }
  83 
  84 inline jlong addr_to_java(void* p) {
  85   assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
  86   return (uintptr_t)p;
  87 }
  88 
  89 
  90 // Note: The VM's obj_field and related accessors use byte-scaled
  91 // ("unscaled") offsets, just as the unsafe methods do.
  92 
  93 // However, the method Unsafe.fieldOffset explicitly declines to
  94 // guarantee this.  The field offset values manipulated by the Java user
  95 // through the Unsafe API are opaque cookies that just happen to be byte
  96 // offsets.  We represent this state of affairs by passing the cookies
  97 // through conversion functions when going between the VM and the Unsafe API.
  98 // The conversion functions just happen to be no-ops at present.
  99 
 100 inline jlong field_offset_to_byte_offset(jlong field_offset) {
 101   return field_offset;
 102 }
 103 
 104 inline jlong field_offset_from_byte_offset(jlong byte_offset) {
 105   return byte_offset;
 106 }
 107 
 108 inline jint invocation_key_from_method_slot(jint slot) {
 109   return slot;
 110 }
 111 
 112 inline jint invocation_key_to_method_slot(jint key) {
 113   return key;
 114 }
 115 
 116 inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
 117   jlong byte_offset = field_offset_to_byte_offset(field_offset);
 118 #ifdef ASSERT
 119   if (p != NULL) {
 120     assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
 121     if (byte_offset == (jint)byte_offset) {
 122       void* ptr_plus_disp = (address)p + byte_offset;
 123       assert((void*)p->obj_field_addr<oop>((jint)byte_offset) == ptr_plus_disp,
 124              "raw [ptr+disp] must be consistent with oop::field_base");
 125     }
 126     jlong p_size = HeapWordSize * (jlong)(p->size());
 127     assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, byte_offset, p_size);
 128   }
 129 #endif
 130   if (sizeof(char*) == sizeof(jint))    // (this constant folds!)
 131     return (address)p + (jint) byte_offset;
 132   else
 133     return (address)p +        byte_offset;
 134 }
 135 
 136 // Externally callable versions:
 137 // (Use these in compiler intrinsics which emulate unsafe primitives.)
 138 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
 139   return field_offset;
 140 }
 141 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
 142   return byte_offset;
 143 }
 144 jint Unsafe_invocation_key_from_method_slot(jint slot) {
 145   return invocation_key_from_method_slot(slot);
 146 }
 147 jint Unsafe_invocation_key_to_method_slot(jint key) {
 148   return invocation_key_to_method_slot(key);
 149 }
 150 
 151 
 152 ///// Data in the Java heap.
 153 
 154 #define GET_FIELD(obj, offset, type_name, v) \
 155   oop p = JNIHandles::resolve(obj); \
 156   type_name v = *(type_name*)index_oop_from_field_offset_long(p, offset)
 157 
 158 #define SET_FIELD(obj, offset, type_name, x) \
 159   oop p = JNIHandles::resolve(obj); \
 160   *(type_name*)index_oop_from_field_offset_long(p, offset) = x
 161 
 162 #define GET_FIELD_VOLATILE(obj, offset, type_name, v) \
 163   oop p = JNIHandles::resolve(obj); \
 164   if (support_IRIW_for_not_multiple_copy_atomic_cpu) { \
 165     OrderAccess::fence(); \
 166   } \
 167   volatile type_name v = OrderAccess::load_acquire((volatile type_name*)index_oop_from_field_offset_long(p, offset));
 168 
 169 #define SET_FIELD_VOLATILE(obj, offset, type_name, x) \
 170   oop p = JNIHandles::resolve(obj); \
 171   OrderAccess::release_store_fence((volatile type_name*)index_oop_from_field_offset_long(p, offset), x);
 172 
 173 
 174 // Get/SetObject must be special-cased, since it works with handles.
 175 
 176 // These functions allow a null base pointer with an arbitrary address.
 177 // But if the base pointer is non-null, the offset should make some sense.
 178 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
 179 UNSAFE_ENTRY(jobject, Unsafe_GetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset))
 180   UnsafeWrapper("Unsafe_GetObject");
 181   oop p = JNIHandles::resolve(obj);
 182   oop v;
 183   if (UseCompressedOops) {
 184     narrowOop n = *(narrowOop*)index_oop_from_field_offset_long(p, offset);
 185     v = oopDesc::decode_heap_oop(n);
 186   } else {
 187     v = *(oop*)index_oop_from_field_offset_long(p, offset);
 188   }
 189   jobject ret = JNIHandles::make_local(env, v);
 190 #if INCLUDE_ALL_GCS
 191   // We could be accessing the referent field in a reference
 192   // object. If G1 is enabled then we need to register non-null
 193   // referent with the SATB barrier.
 194   if (UseG1GC) {
 195     bool needs_barrier = false;
 196 
 197     if (ret != NULL) {
 198       if (offset == java_lang_ref_Reference::referent_offset && obj != NULL) {
 199         oop o = JNIHandles::resolve(obj);
 200         Klass* k = o->klass();
 201         if (InstanceKlass::cast(k)->reference_type() != REF_NONE) {
 202           assert(InstanceKlass::cast(k)->is_subclass_of(SystemDictionary::Reference_klass()), "sanity");
 203           needs_barrier = true;
 204         }
 205       }
 206     }
 207 
 208     if (needs_barrier) {
 209       oop referent = JNIHandles::resolve(ret);
 210       G1SATBCardTableModRefBS::enqueue(referent);
 211     }
 212   }
 213 #endif // INCLUDE_ALL_GCS
 214   return ret;
 215 UNSAFE_END
 216 
 217 UNSAFE_ENTRY(void, Unsafe_SetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
 218   UnsafeWrapper("Unsafe_SetObject");
 219   oop x = JNIHandles::resolve(x_h);
 220   oop p = JNIHandles::resolve(obj);
 221   if (UseCompressedOops) {
 222     oop_store((narrowOop*)index_oop_from_field_offset_long(p, offset), x);
 223   } else {
 224     oop_store((oop*)index_oop_from_field_offset_long(p, offset), x);
 225   }
 226 UNSAFE_END
 227 
 228 UNSAFE_ENTRY(jobject, Unsafe_GetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset))
 229   UnsafeWrapper("Unsafe_GetObjectVolatile");
 230   oop p = JNIHandles::resolve(obj);
 231   void* addr = index_oop_from_field_offset_long(p, offset);
 232   volatile oop v;
 233   if (UseCompressedOops) {
 234     volatile narrowOop n = *(volatile narrowOop*) addr;
 235     (void)const_cast<oop&>(v = oopDesc::decode_heap_oop(n));
 236   } else {
 237     (void)const_cast<oop&>(v = *(volatile oop*) addr);
 238   }
 239   OrderAccess::acquire();
 240   return JNIHandles::make_local(env, v);
 241 UNSAFE_END
 242 
 243 UNSAFE_ENTRY(void, Unsafe_SetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
 244   UnsafeWrapper("Unsafe_SetObjectVolatile");
 245   oop x = JNIHandles::resolve(x_h);
 246   oop p = JNIHandles::resolve(obj);
 247   void* addr = index_oop_from_field_offset_long(p, offset);
 248   OrderAccess::release();
 249   if (UseCompressedOops) {
 250     oop_store((narrowOop*)addr, x);
 251   } else {
 252     oop_store((oop*)addr, x);
 253   }
 254   OrderAccess::fence();
 255 UNSAFE_END
 256 
 257 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr))
 258   UnsafeWrapper("Unsafe_GetUncompressedObject");
 259   oop v = *(oop*) (address) addr;
 260   return JNIHandles::make_local(env, v);
 261 UNSAFE_END
 262 
 263 UNSAFE_ENTRY(jclass, Unsafe_GetJavaMirror(JNIEnv *env, jobject unsafe, jlong metaspace_klass))
 264   UnsafeWrapper("Unsafe_GetJavaMirror");
 265   Klass* klass = (Klass*) (address) metaspace_klass;
 266   return (jclass) JNIHandles::make_local(klass->java_mirror());
 267 UNSAFE_END
 268 
 269 UNSAFE_ENTRY(jlong, Unsafe_GetKlassPointer(JNIEnv *env, jobject unsafe, jobject obj))
 270   UnsafeWrapper("Unsafe_GetKlassPointer");
 271   oop o = JNIHandles::resolve(obj);
 272   jlong klass = (jlong) (address) o->klass();
 273   return klass;
 274 UNSAFE_END
 275 
 276 #ifndef SUPPORTS_NATIVE_CX8
 277 
 278 // VM_Version::supports_cx8() is a surrogate for 'supports atomic long memory ops'.
 279 //
 280 // On platforms which do not support atomic compare-and-swap of jlong (8 byte)
 281 // values we have to use a lock-based scheme to enforce atomicity. This has to be
 282 // applied to all Unsafe operations that set the value of a jlong field. Even so
 283 // the compareAndSwapLong operation will not be atomic with respect to direct stores
 284 // to the field from Java code. It is important therefore that any Java code that
 285 // utilizes these Unsafe jlong operations does not perform direct stores. To permit
 286 // direct loads of the field from Java code we must also use Atomic::store within the
 287 // locked regions. And for good measure, in case there are direct stores, we also
 288 // employ Atomic::load within those regions. Note that the field in question must be
 289 // volatile and so must have atomic load/store accesses applied at the Java level.
 290 //
 291 // The locking scheme could utilize a range of strategies for controlling the locking
 292 // granularity: from a lock per-field through to a single global lock. The latter is
 293 // the simplest and is used for the current implementation. Note that the Java object
 294 // that contains the field, can not, in general, be used for locking. To do so can lead
 295 // to deadlocks as we may introduce locking into what appears to the Java code to be a
 296 // lock-free path.
 297 //
 298 // As all the locked-regions are very short and themselves non-blocking we can treat
 299 // them as leaf routines and elide safepoint checks (ie we don't perform any thread
 300 // state transitions even when blocking for the lock). Note that if we do choose to
 301 // add safepoint checks and thread state transitions, we must ensure that we calculate
 302 // the address of the field _after_ we have acquired the lock, else the object may have
 303 // been moved by the GC
 304 
 305 UNSAFE_ENTRY(jlong, Unsafe_GetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset))
 306   UnsafeWrapper("Unsafe_GetLongVolatile");
 307   {
 308     if (VM_Version::supports_cx8()) {
 309       GET_FIELD_VOLATILE(obj, offset, jlong, v);
 310       return v;
 311     }
 312     else {
 313       Handle p (THREAD, JNIHandles::resolve(obj));
 314       jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
 315       MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
 316       jlong value = Atomic::load(addr);
 317       return value;
 318     }
 319   }
 320 UNSAFE_END
 321 
 322 UNSAFE_ENTRY(void, Unsafe_SetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x))
 323   UnsafeWrapper("Unsafe_SetLongVolatile");
 324   {
 325     if (VM_Version::supports_cx8()) {
 326       SET_FIELD_VOLATILE(obj, offset, jlong, x);
 327     }
 328     else {
 329       Handle p (THREAD, JNIHandles::resolve(obj));
 330       jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
 331       MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
 332       Atomic::store(x, addr);
 333     }
 334   }
 335 UNSAFE_END
 336 
 337 #endif // not SUPPORTS_NATIVE_CX8
 338 
 339 UNSAFE_ENTRY(jboolean, Unsafe_isBigEndian0(JNIEnv *env, jobject unsafe))
 340   UnsafeWrapper("Unsafe_IsBigEndian0");
 341   {
 342 #ifdef VM_LITTLE_ENDIAN
 343     return false;
 344 #else
 345     return true;
 346 #endif
 347   }
 348 UNSAFE_END
 349 
 350 UNSAFE_ENTRY(jint, Unsafe_unalignedAccess0(JNIEnv *env, jobject unsafe))
 351   UnsafeWrapper("Unsafe_UnalignedAccess0");
 352   {
 353     return UseUnalignedAccesses;
 354   }
 355 UNSAFE_END
 356 
 357 #define DEFINE_GETSETOOP(jboolean, Boolean) \
 358  \
 359 UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean##140(JNIEnv *env, jobject unsafe, jobject obj, jint offset)) \
 360   UnsafeWrapper("Unsafe_Get"#Boolean); \
 361   if (obj == NULL)  THROW_0(vmSymbols::java_lang_NullPointerException()); \
 362   GET_FIELD(obj, offset, jboolean, v); \
 363   return v; \
 364 UNSAFE_END \
 365  \
 366 UNSAFE_ENTRY(void, Unsafe_Set##Boolean##140(JNIEnv *env, jobject unsafe, jobject obj, jint offset, jboolean x)) \
 367   UnsafeWrapper("Unsafe_Set"#Boolean); \
 368   if (obj == NULL)  THROW(vmSymbols::java_lang_NullPointerException()); \
 369   SET_FIELD(obj, offset, jboolean, x); \
 370 UNSAFE_END \
 371  \
 372 UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) \
 373   UnsafeWrapper("Unsafe_Get"#Boolean); \
 374   GET_FIELD(obj, offset, jboolean, v); \
 375   return v; \
 376 UNSAFE_END \
 377  \
 378 UNSAFE_ENTRY(void, Unsafe_Set##Boolean(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jboolean x)) \
 379   UnsafeWrapper("Unsafe_Set"#Boolean); \
 380   SET_FIELD(obj, offset, jboolean, x); \
 381 UNSAFE_END \
 382  \
 383 // END DEFINE_GETSETOOP.
 384 
 385 DEFINE_GETSETOOP(jboolean, Boolean)
 386 DEFINE_GETSETOOP(jbyte, Byte)
 387 DEFINE_GETSETOOP(jshort, Short);
 388 DEFINE_GETSETOOP(jchar, Char);
 389 DEFINE_GETSETOOP(jint, Int);
 390 DEFINE_GETSETOOP(jlong, Long);
 391 DEFINE_GETSETOOP(jfloat, Float);
 392 DEFINE_GETSETOOP(jdouble, Double);
 393 
 394 #undef DEFINE_GETSETOOP
 395 
 396 #define DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean) \
 397  \
 398 UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) \
 399   UnsafeWrapper("Unsafe_Get"#Boolean); \
 400   GET_FIELD_VOLATILE(obj, offset, jboolean, v); \
 401   return v; \
 402 UNSAFE_END \
 403  \
 404 UNSAFE_ENTRY(void, Unsafe_Set##Boolean##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jboolean x)) \
 405   UnsafeWrapper("Unsafe_Set"#Boolean); \
 406   SET_FIELD_VOLATILE(obj, offset, jboolean, x); \
 407 UNSAFE_END \
 408  \
 409 // END DEFINE_GETSETOOP_VOLATILE.
 410 
 411 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
 412 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
 413 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
 414 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
 415 DEFINE_GETSETOOP_VOLATILE(jint, Int);
 416 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
 417 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
 418 
 419 #ifdef SUPPORTS_NATIVE_CX8
 420 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
 421 #endif
 422 
 423 #undef DEFINE_GETSETOOP_VOLATILE
 424 
 425 // The non-intrinsified versions of setOrdered just use setVolatile
 426 
 427 UNSAFE_ENTRY(void, Unsafe_SetOrderedInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint x))
 428   UnsafeWrapper("Unsafe_SetOrderedInt");
 429   SET_FIELD_VOLATILE(obj, offset, jint, x);
 430 UNSAFE_END
 431 
 432 UNSAFE_ENTRY(void, Unsafe_SetOrderedObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
 433   UnsafeWrapper("Unsafe_SetOrderedObject");
 434   oop x = JNIHandles::resolve(x_h);
 435   oop p = JNIHandles::resolve(obj);
 436   void* addr = index_oop_from_field_offset_long(p, offset);
 437   OrderAccess::release();
 438   if (UseCompressedOops) {
 439     oop_store((narrowOop*)addr, x);
 440   } else {
 441     oop_store((oop*)addr, x);
 442   }
 443   OrderAccess::fence();
 444 UNSAFE_END
 445 
 446 UNSAFE_ENTRY(void, Unsafe_SetOrderedLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x))
 447   UnsafeWrapper("Unsafe_SetOrderedLong");
 448 #ifdef SUPPORTS_NATIVE_CX8
 449   SET_FIELD_VOLATILE(obj, offset, jlong, x);
 450 #else
 451   // Keep old code for platforms which may not have atomic long (8 bytes) instructions
 452   {
 453     if (VM_Version::supports_cx8()) {
 454       SET_FIELD_VOLATILE(obj, offset, jlong, x);
 455     }
 456     else {
 457       Handle p (THREAD, JNIHandles::resolve(obj));
 458       jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
 459       MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
 460       Atomic::store(x, addr);
 461     }
 462   }
 463 #endif
 464 UNSAFE_END
 465 
 466 UNSAFE_ENTRY(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe))
 467   UnsafeWrapper("Unsafe_LoadFence");
 468   OrderAccess::acquire();
 469 UNSAFE_END
 470 
 471 UNSAFE_ENTRY(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe))
 472   UnsafeWrapper("Unsafe_StoreFence");
 473   OrderAccess::release();
 474 UNSAFE_END
 475 
 476 UNSAFE_ENTRY(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe))
 477   UnsafeWrapper("Unsafe_FullFence");
 478   OrderAccess::fence();
 479 UNSAFE_END
 480 
 481 ////// Data in the C heap.
 482 
 483 // Note:  These do not throw NullPointerException for bad pointers.
 484 // They just crash.  Only a oop base pointer can generate a NullPointerException.
 485 //
 486 #define DEFINE_GETSETNATIVE(java_type, Type, native_type) \
 487  \
 488 UNSAFE_ENTRY(java_type, Unsafe_GetNative##Type(JNIEnv *env, jobject unsafe, jlong addr)) \
 489   UnsafeWrapper("Unsafe_GetNative"#Type); \
 490   void* p = addr_from_java(addr); \
 491   JavaThread* t = JavaThread::current(); \
 492   t->set_doing_unsafe_access(true); \
 493   java_type x = *(volatile native_type*)p; \
 494   t->set_doing_unsafe_access(false); \
 495   return x; \
 496 UNSAFE_END \
 497  \
 498 UNSAFE_ENTRY(void, Unsafe_SetNative##Type(JNIEnv *env, jobject unsafe, jlong addr, java_type x)) \
 499   UnsafeWrapper("Unsafe_SetNative"#Type); \
 500   JavaThread* t = JavaThread::current(); \
 501   t->set_doing_unsafe_access(true); \
 502   void* p = addr_from_java(addr); \
 503   *(volatile native_type*)p = x; \
 504   t->set_doing_unsafe_access(false); \
 505 UNSAFE_END \
 506  \
 507 // END DEFINE_GETSETNATIVE.
 508 
 509 DEFINE_GETSETNATIVE(jbyte, Byte, signed char)
 510 DEFINE_GETSETNATIVE(jshort, Short, signed short);
 511 DEFINE_GETSETNATIVE(jchar, Char, unsigned short);
 512 DEFINE_GETSETNATIVE(jint, Int, jint);
 513 // no long -- handled specially
 514 DEFINE_GETSETNATIVE(jfloat, Float, float);
 515 DEFINE_GETSETNATIVE(jdouble, Double, double);
 516 
 517 #undef DEFINE_GETSETNATIVE
 518 
 519 UNSAFE_ENTRY(jlong, Unsafe_GetNativeLong(JNIEnv *env, jobject unsafe, jlong addr))
 520   UnsafeWrapper("Unsafe_GetNativeLong");
 521   JavaThread* t = JavaThread::current();
 522   // We do it this way to avoid problems with access to heap using 64
 523   // bit loads, as jlong in heap could be not 64-bit aligned, and on
 524   // some CPUs (SPARC) it leads to SIGBUS.
 525   t->set_doing_unsafe_access(true);
 526   void* p = addr_from_java(addr);
 527   jlong x;
 528   if (((intptr_t)p & 7) == 0) {
 529     // jlong is aligned, do a volatile access
 530     x = *(volatile jlong*)p;
 531   } else {
 532     jlong_accessor acc;
 533     acc.words[0] = ((volatile jint*)p)[0];
 534     acc.words[1] = ((volatile jint*)p)[1];
 535     x = acc.long_value;
 536   }
 537   t->set_doing_unsafe_access(false);
 538   return x;
 539 UNSAFE_END
 540 
 541 UNSAFE_ENTRY(void, Unsafe_SetNativeLong(JNIEnv *env, jobject unsafe, jlong addr, jlong x))
 542   UnsafeWrapper("Unsafe_SetNativeLong");
 543   JavaThread* t = JavaThread::current();
 544   // see comment for Unsafe_GetNativeLong
 545   t->set_doing_unsafe_access(true);
 546   void* p = addr_from_java(addr);
 547   if (((intptr_t)p & 7) == 0) {
 548     // jlong is aligned, do a volatile access
 549     *(volatile jlong*)p = x;
 550   } else {
 551     jlong_accessor acc;
 552     acc.long_value = x;
 553     ((volatile jint*)p)[0] = acc.words[0];
 554     ((volatile jint*)p)[1] = acc.words[1];
 555   }
 556   t->set_doing_unsafe_access(false);
 557 UNSAFE_END
 558 
 559 
 560 UNSAFE_ENTRY(jlong, Unsafe_GetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr))
 561   UnsafeWrapper("Unsafe_GetNativeAddress");
 562   void* p = addr_from_java(addr);
 563   return addr_to_java(*(void**)p);
 564 UNSAFE_END
 565 
 566 UNSAFE_ENTRY(void, Unsafe_SetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr, jlong x))
 567   UnsafeWrapper("Unsafe_SetNativeAddress");
 568   void* p = addr_from_java(addr);
 569   *(void**)p = addr_from_java(x);
 570 UNSAFE_END
 571 
 572 
 573 ////// Allocation requests
 574 
 575 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls))
 576   UnsafeWrapper("Unsafe_AllocateInstance");
 577   {
 578     ThreadToNativeFromVM ttnfv(thread);
 579     return env->AllocObject(cls);
 580   }
 581 UNSAFE_END
 582 
 583 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory(JNIEnv *env, jobject unsafe, jlong size))
 584   UnsafeWrapper("Unsafe_AllocateMemory");
 585   size_t sz = (size_t)size;
 586   if (sz != (julong)size || size < 0) {
 587     THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 588   }
 589   if (sz == 0) {
 590     return 0;
 591   }
 592   sz = round_to(sz, HeapWordSize);
 593   void* x = os::malloc(sz, mtInternal);
 594   if (x == NULL) {
 595     THROW_0(vmSymbols::java_lang_OutOfMemoryError());
 596   }
 597   //Copy::fill_to_words((HeapWord*)x, sz / HeapWordSize);
 598   return addr_to_java(x);
 599 UNSAFE_END
 600 
 601 UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory(JNIEnv *env, jobject unsafe, jlong addr, jlong size))
 602   UnsafeWrapper("Unsafe_ReallocateMemory");
 603   void* p = addr_from_java(addr);
 604   size_t sz = (size_t)size;
 605   if (sz != (julong)size || size < 0) {
 606     THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 607   }
 608   if (sz == 0) {
 609     os::free(p);
 610     return 0;
 611   }
 612   sz = round_to(sz, HeapWordSize);
 613   void* x = (p == NULL) ? os::malloc(sz, mtInternal) : os::realloc(p, sz, mtInternal);
 614   if (x == NULL) {
 615     THROW_0(vmSymbols::java_lang_OutOfMemoryError());
 616   }
 617   return addr_to_java(x);
 618 UNSAFE_END
 619 
 620 UNSAFE_ENTRY(void, Unsafe_FreeMemory(JNIEnv *env, jobject unsafe, jlong addr))
 621   UnsafeWrapper("Unsafe_FreeMemory");
 622   void* p = addr_from_java(addr);
 623   if (p == NULL) {
 624     return;
 625   }
 626   os::free(p);
 627 UNSAFE_END
 628 
 629 UNSAFE_ENTRY(void, Unsafe_SetMemory(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value))
 630   UnsafeWrapper("Unsafe_SetMemory");
 631   size_t sz = (size_t)size;
 632   if (sz != (julong)size || size < 0) {
 633     THROW(vmSymbols::java_lang_IllegalArgumentException());
 634   }
 635   oop base = JNIHandles::resolve(obj);
 636   void* p = index_oop_from_field_offset_long(base, offset);
 637   Copy::fill_to_memory_atomic(p, sz, value);
 638 UNSAFE_END
 639 
 640 UNSAFE_ENTRY(void, Unsafe_CopyMemory(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size))
 641   UnsafeWrapper("Unsafe_CopyMemory");
 642   if (size == 0) {
 643     return;
 644   }
 645   size_t sz = (size_t)size;
 646   if (sz != (julong)size || size < 0) {
 647     THROW(vmSymbols::java_lang_IllegalArgumentException());
 648   }
 649   oop srcp = JNIHandles::resolve(srcObj);
 650   oop dstp = JNIHandles::resolve(dstObj);
 651   if (dstp != NULL && !dstp->is_typeArray()) {
 652     // NYI:  This works only for non-oop arrays at present.
 653     // Generalizing it would be reasonable, but requires card marking.
 654     // Also, autoboxing a Long from 0L in copyMemory(x,y, 0L,z, n) would be bad.
 655     THROW(vmSymbols::java_lang_IllegalArgumentException());
 656   }
 657   void* src = index_oop_from_field_offset_long(srcp, srcOffset);
 658   void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
 659   Copy::conjoint_memory_atomic(src, dst, sz);
 660 UNSAFE_END
 661 
 662 
 663 ////// Random queries
 664 
 665 // See comment at file start about UNSAFE_LEAF
 666 //UNSAFE_LEAF(jint, Unsafe_AddressSize())
 667 UNSAFE_ENTRY(jint, Unsafe_AddressSize(JNIEnv *env, jobject unsafe))
 668   UnsafeWrapper("Unsafe_AddressSize");
 669   return sizeof(void*);
 670 UNSAFE_END
 671 
 672 // See comment at file start about UNSAFE_LEAF
 673 //UNSAFE_LEAF(jint, Unsafe_PageSize())
 674 UNSAFE_ENTRY(jint, Unsafe_PageSize(JNIEnv *env, jobject unsafe))
 675   UnsafeWrapper("Unsafe_PageSize");
 676   return os::vm_page_size();
 677 UNSAFE_END
 678 
 679 jint find_field_offset(jobject field, int must_be_static, TRAPS) {
 680   if (field == NULL) {
 681     THROW_0(vmSymbols::java_lang_NullPointerException());
 682   }
 683 
 684   oop reflected   = JNIHandles::resolve_non_null(field);
 685   oop mirror      = java_lang_reflect_Field::clazz(reflected);
 686   Klass* k      = java_lang_Class::as_Klass(mirror);
 687   int slot        = java_lang_reflect_Field::slot(reflected);
 688   int modifiers   = java_lang_reflect_Field::modifiers(reflected);
 689 
 690   if (must_be_static >= 0) {
 691     int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
 692     if (must_be_static != really_is_static) {
 693       THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 694     }
 695   }
 696 
 697   int offset = InstanceKlass::cast(k)->field_offset(slot);
 698   return field_offset_from_byte_offset(offset);
 699 }
 700 
 701 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset(JNIEnv *env, jobject unsafe, jobject field))
 702   UnsafeWrapper("Unsafe_ObjectFieldOffset");
 703   return find_field_offset(field, 0, THREAD);
 704 UNSAFE_END
 705 
 706 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset(JNIEnv *env, jobject unsafe, jobject field))
 707   UnsafeWrapper("Unsafe_StaticFieldOffset");
 708   return find_field_offset(field, 1, THREAD);
 709 UNSAFE_END
 710 
 711 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBaseFromField(JNIEnv *env, jobject unsafe, jobject field))
 712   UnsafeWrapper("Unsafe_StaticFieldBase");
 713   // Note:  In this VM implementation, a field address is always a short
 714   // offset from the base of a a klass metaobject.  Thus, the full dynamic
 715   // range of the return type is never used.  However, some implementations
 716   // might put the static field inside an array shared by many classes,
 717   // or even at a fixed address, in which case the address could be quite
 718   // large.  In that last case, this function would return NULL, since
 719   // the address would operate alone, without any base pointer.
 720 
 721   if (field == NULL)  THROW_0(vmSymbols::java_lang_NullPointerException());
 722 
 723   oop reflected   = JNIHandles::resolve_non_null(field);
 724   oop mirror      = java_lang_reflect_Field::clazz(reflected);
 725   int modifiers   = java_lang_reflect_Field::modifiers(reflected);
 726 
 727   if ((modifiers & JVM_ACC_STATIC) == 0) {
 728     THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 729   }
 730 
 731   return JNIHandles::make_local(env, mirror);
 732 UNSAFE_END
 733 
 734 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized(JNIEnv *env, jobject unsafe, jobject clazz)) {
 735   UnsafeWrapper("Unsafe_EnsureClassInitialized");
 736   if (clazz == NULL) {
 737     THROW(vmSymbols::java_lang_NullPointerException());
 738   }
 739   oop mirror = JNIHandles::resolve_non_null(clazz);
 740 
 741   Klass* klass = java_lang_Class::as_Klass(mirror);
 742   if (klass != NULL && klass->should_be_initialized()) {
 743     InstanceKlass* k = InstanceKlass::cast(klass);
 744     k->initialize(CHECK);
 745   }
 746 }
 747 UNSAFE_END
 748 
 749 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized(JNIEnv *env, jobject unsafe, jobject clazz)) {
 750   UnsafeWrapper("Unsafe_ShouldBeInitialized");
 751   if (clazz == NULL) {
 752     THROW_(vmSymbols::java_lang_NullPointerException(), false);
 753   }
 754   oop mirror = JNIHandles::resolve_non_null(clazz);
 755   Klass* klass = java_lang_Class::as_Klass(mirror);
 756   if (klass != NULL && klass->should_be_initialized()) {
 757     return true;
 758   }
 759   return false;
 760 }
 761 UNSAFE_END
 762 
 763 static void getBaseAndScale(int& base, int& scale, jclass acls, TRAPS) {
 764   if (acls == NULL) {
 765     THROW(vmSymbols::java_lang_NullPointerException());
 766   }
 767   oop      mirror = JNIHandles::resolve_non_null(acls);
 768   Klass* k      = java_lang_Class::as_Klass(mirror);
 769   if (k == NULL || !k->oop_is_array()) {
 770     THROW(vmSymbols::java_lang_InvalidClassException());
 771   } else if (k->oop_is_objArray()) {
 772     base  = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
 773     scale = heapOopSize;
 774   } else if (k->oop_is_typeArray()) {
 775     TypeArrayKlass* tak = TypeArrayKlass::cast(k);
 776     base  = tak->array_header_in_bytes();
 777     assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
 778     scale = (1 << tak->log2_element_size());
 779   } else {
 780     ShouldNotReachHere();
 781   }
 782 }
 783 
 784 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset(JNIEnv *env, jobject unsafe, jclass acls))
 785   UnsafeWrapper("Unsafe_ArrayBaseOffset");
 786   int base, scale;
 787   getBaseAndScale(base, scale, acls, CHECK_0);
 788   return field_offset_from_byte_offset(base);
 789 UNSAFE_END
 790 
 791 
 792 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale(JNIEnv *env, jobject unsafe, jclass acls))
 793   UnsafeWrapper("Unsafe_ArrayIndexScale");
 794   int base, scale;
 795   getBaseAndScale(base, scale, acls, CHECK_0);
 796   // This VM packs both fields and array elements down to the byte.
 797   // But watch out:  If this changes, so that array references for
 798   // a given primitive type (say, T_BOOLEAN) use different memory units
 799   // than fields, this method MUST return zero for such arrays.
 800   // For example, the VM used to store sub-word sized fields in full
 801   // words in the object layout, so that accessors like getByte(Object,int)
 802   // did not really do what one might expect for arrays.  Therefore,
 803   // this function used to report a zero scale factor, so that the user
 804   // would know not to attempt to access sub-word array elements.
 805   // // Code for unpacked fields:
 806   // if (scale < wordSize)  return 0;
 807 
 808   // The following allows for a pretty general fieldOffset cookie scheme,
 809   // but requires it to be linear in byte offset.
 810   return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
 811 UNSAFE_END
 812 
 813 
 814 static inline void throw_new(JNIEnv *env, const char *ename) {
 815   char buf[100];
 816   jio_snprintf(buf, 100, "%s%s", "java/lang/", ename);
 817   jclass cls = env->FindClass(buf);
 818   if (env->ExceptionCheck()) {
 819     env->ExceptionClear();
 820     tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", buf);
 821     return;
 822   }
 823   char* msg = NULL;
 824   env->ThrowNew(cls, msg);
 825 }
 826 
 827 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
 828   {
 829     // Code lifted from JDK 1.3 ClassLoader.c
 830 
 831     jbyte *body;
 832     char *utfName;
 833     jclass result = 0;
 834     char buf[128];
 835 
 836     if (UsePerfData) {
 837       ClassLoader::unsafe_defineClassCallCounter()->inc();
 838     }
 839 
 840     if (data == NULL) {
 841         throw_new(env, "NullPointerException");
 842         return 0;
 843     }
 844 
 845     /* Work around 4153825. malloc crashes on Solaris when passed a
 846      * negative size.
 847      */
 848     if (length < 0) {
 849         throw_new(env, "ArrayIndexOutOfBoundsException");
 850         return 0;
 851     }
 852 
 853     body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
 854 
 855     if (body == 0) {
 856         throw_new(env, "OutOfMemoryError");
 857         return 0;
 858     }
 859 
 860     env->GetByteArrayRegion(data, offset, length, body);
 861 
 862     if (env->ExceptionOccurred())
 863         goto free_body;
 864 
 865     if (name != NULL) {
 866         uint len = env->GetStringUTFLength(name);
 867         int unicode_len = env->GetStringLength(name);
 868         if (len >= sizeof(buf)) {
 869             utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
 870             if (utfName == NULL) {
 871                 throw_new(env, "OutOfMemoryError");
 872                 goto free_body;
 873             }
 874         } else {
 875             utfName = buf;
 876         }
 877         env->GetStringUTFRegion(name, 0, unicode_len, utfName);
 878         //VerifyFixClassname(utfName);
 879         for (uint i = 0; i < len; i++) {
 880           if (utfName[i] == '.')   utfName[i] = '/';
 881         }
 882     } else {
 883         utfName = NULL;
 884     }
 885 
 886     result = JVM_DefineClass(env, utfName, loader, body, length, pd);
 887 
 888     if (utfName && utfName != buf)
 889         FREE_C_HEAP_ARRAY(char, utfName);
 890 
 891  free_body:
 892     FREE_C_HEAP_ARRAY(jbyte, body);
 893     return result;
 894   }
 895 }
 896 
 897 
 898 UNSAFE_ENTRY(jclass, Unsafe_DefineClass(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd))
 899   UnsafeWrapper("Unsafe_DefineClass");
 900   {
 901     ThreadToNativeFromVM ttnfv(thread);
 902     return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
 903   }
 904 UNSAFE_END
 905 
 906 
 907 // define a class but do not make it known to the class loader or system dictionary
 908 // - host_class:  supplies context for linkage, access control, protection domain, and class loader
 909 // - data:  bytes of a class file, a raw memory address (length gives the number of bytes)
 910 // - cp_patches:  where non-null entries exist, they replace corresponding CP entries in data
 911 
 912 // When you load an anonymous class U, it works as if you changed its name just before loading,
 913 // to a name that you will never use again.  Since the name is lost, no other class can directly
 914 // link to any member of U.  Just after U is loaded, the only way to use it is reflectively,
 915 // through java.lang.Class methods like Class.newInstance.
 916 
 917 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
 918 // The package of an anonymous class is given by the package qualifier on the name under which it was loaded.
 919 // An anonymous class also has special privileges to access any member of its host class.
 920 // This is the main reason why this loading operation is unsafe.  The purpose of this is to
 921 // allow language implementations to simulate "open classes"; a host class in effect gets
 922 // new code when an anonymous class is loaded alongside it.  A less convenient but more
 923 // standard way to do this is with reflection, which can also be set to ignore access
 924 // restrictions.
 925 
 926 // Access into an anonymous class is possible only through reflection.  Therefore, there
 927 // are no special access rules for calling into an anonymous class.  The relaxed access
 928 // rule for the host class is applied in the opposite direction:  A host class reflectively
 929 // access one of its anonymous classes.
 930 
 931 // If you load the same bytecodes twice, you get two different classes.  You can reload
 932 // the same bytecodes with or without varying CP patches.
 933 
 934 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
 935 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
 936 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
 937 
 938 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
 939 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
 940 // It is not possible for a named class, or an older anonymous class, to refer by
 941 // name (via its CP) to a newer anonymous class.
 942 
 943 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
 944 // or type descriptors used in the loaded anonymous class.
 945 
 946 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
 947 // instead of "dead" strings.  A compiled statement like println((Object)"hello") can
 948 // be changed to println(greeting), where greeting is an arbitrary object created before
 949 // the anonymous class is loaded.  This is useful in dynamic languages, in which
 950 // various kinds of metaobjects must be introduced as constants into bytecode.
 951 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
 952 // not just a literal string.  For such ldc instructions, the verifier uses the
 953 // type Object instead of String, if the loaded constant is not in fact a String.
 954 
 955 static instanceKlassHandle
 956 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
 957                                  jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
 958                                  HeapWord* *temp_alloc,
 959                                  TRAPS) {
 960 
 961   if (UsePerfData) {
 962     ClassLoader::unsafe_defineClassCallCounter()->inc();
 963   }
 964 
 965   if (data == NULL) {
 966     THROW_0(vmSymbols::java_lang_NullPointerException());
 967   }
 968 
 969   jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
 970   jint word_length = (length + sizeof(HeapWord)-1) / sizeof(HeapWord);
 971   HeapWord* body = NEW_C_HEAP_ARRAY(HeapWord, word_length, mtInternal);
 972   if (body == NULL) {
 973     THROW_0(vmSymbols::java_lang_OutOfMemoryError());
 974   }
 975 
 976   // caller responsible to free it:
 977   (*temp_alloc) = body;
 978 
 979   {
 980     jbyte* array_base = typeArrayOop(JNIHandles::resolve_non_null(data))->byte_at_addr(0);
 981     Copy::conjoint_words((HeapWord*) array_base, body, word_length);
 982   }
 983 
 984   u1* class_bytes = (u1*) body;
 985   int class_bytes_length = (int) length;
 986   if (class_bytes_length < 0)  class_bytes_length = 0;
 987   if (class_bytes == NULL
 988       || host_class == NULL
 989       || length != class_bytes_length)
 990     THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 991 
 992   objArrayHandle cp_patches_h;
 993   if (cp_patches_jh != NULL) {
 994     oop p = JNIHandles::resolve_non_null(cp_patches_jh);
 995     if (!p->is_objArray())
 996       THROW_0(vmSymbols::java_lang_IllegalArgumentException());
 997     cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
 998   }
 999 
1000   KlassHandle host_klass(THREAD, java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class)));
1001   const char* host_source = host_klass->external_name();
1002   Handle      host_loader(THREAD, host_klass->class_loader());
1003   Handle      host_domain(THREAD, host_klass->protection_domain());
1004 
1005   GrowableArray<Handle>* cp_patches = NULL;
1006   if (cp_patches_h.not_null()) {
1007     int alen = cp_patches_h->length();
1008     for (int i = alen-1; i >= 0; i--) {
1009       oop p = cp_patches_h->obj_at(i);
1010       if (p != NULL) {
1011         Handle patch(THREAD, p);
1012         if (cp_patches == NULL)
1013           cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
1014         cp_patches->at_put(i, patch);
1015       }
1016     }
1017   }
1018 
1019   ClassFileStream st(class_bytes, class_bytes_length, (char*) host_source);
1020 
1021   instanceKlassHandle anon_klass;
1022   {
1023     Symbol* no_class_name = NULL;
1024     Klass* anonk = SystemDictionary::parse_stream(no_class_name,
1025                                                     host_loader, host_domain,
1026                                                     &st, host_klass, cp_patches,
1027                                                     CHECK_NULL);
1028     if (anonk == NULL)  return NULL;
1029     anon_klass = instanceKlassHandle(THREAD, anonk);
1030   }
1031 
1032   return anon_klass;
1033 }
1034 
1035 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh))
1036 {
1037   instanceKlassHandle anon_klass;
1038   jobject res_jh = NULL;
1039 
1040   UnsafeWrapper("Unsafe_DefineAnonymousClass");
1041   ResourceMark rm(THREAD);
1042 
1043   HeapWord* temp_alloc = NULL;
1044 
1045   anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data,
1046                                                 cp_patches_jh,
1047                                                    &temp_alloc, THREAD);
1048   if (anon_klass() != NULL)
1049     res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
1050 
1051   // try/finally clause:
1052   if (temp_alloc != NULL) {
1053     FREE_C_HEAP_ARRAY(HeapWord, temp_alloc);
1054   }
1055 
1056   // The anonymous class loader data has been artificially been kept alive to
1057   // this point.   The mirror and any instances of this class have to keep
1058   // it alive afterwards.
1059   if (anon_klass() != NULL) {
1060     anon_klass->class_loader_data()->set_keep_alive(false);
1061   }
1062 
1063   // let caller initialize it as needed...
1064 
1065   return (jclass) res_jh;
1066 }
1067 UNSAFE_END
1068 
1069 
1070 
1071 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr))
1072   UnsafeWrapper("Unsafe_ThrowException");
1073   {
1074     ThreadToNativeFromVM ttnfv(thread);
1075     env->Throw(thr);
1076   }
1077 UNSAFE_END
1078 
1079 // JSR166 ------------------------------------------------------------------
1080 
1081 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h))
1082   UnsafeWrapper("Unsafe_CompareAndSwapObject");
1083   oop x = JNIHandles::resolve(x_h);
1084   oop e = JNIHandles::resolve(e_h);
1085   oop p = JNIHandles::resolve(obj);
1086   HeapWord* addr = (HeapWord *)index_oop_from_field_offset_long(p, offset);
1087   oop res = oopDesc::atomic_compare_exchange_oop(x, addr, e, true);
1088   jboolean success  = (res == e);
1089   if (success)
1090     update_barrier_set((void*)addr, x);
1091   return success;
1092 UNSAFE_END
1093 
1094 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x))
1095   UnsafeWrapper("Unsafe_CompareAndSwapInt");
1096   oop p = JNIHandles::resolve(obj);
1097   jint* addr = (jint *) index_oop_from_field_offset_long(p, offset);
1098   return (jint)(Atomic::cmpxchg(x, addr, e)) == e;
1099 UNSAFE_END
1100 
1101 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x))
1102   UnsafeWrapper("Unsafe_CompareAndSwapLong");
1103   Handle p (THREAD, JNIHandles::resolve(obj));
1104   jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
1105 #ifdef SUPPORTS_NATIVE_CX8
1106   return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1107 #else
1108   if (VM_Version::supports_cx8())
1109     return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1110   else {
1111     jboolean success = false;
1112     MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
1113     jlong val = Atomic::load(addr);
1114     if (val == e) { Atomic::store(x, addr); success = true; }
1115     return success;
1116   }
1117 #endif
1118 UNSAFE_END
1119 
1120 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time))
1121   UnsafeWrapper("Unsafe_Park");
1122   EventThreadPark event;
1123   HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1124 
1125   JavaThreadParkedState jtps(thread, time != 0);
1126   thread->parker()->park(isAbsolute != 0, time);
1127 
1128   HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1129   if (event.should_commit()) {
1130     oop obj = thread->current_park_blocker();
1131     event.set_klass((obj != NULL) ? obj->klass() : NULL);
1132     event.set_timeout(time);
1133     event.set_address((obj != NULL) ? (TYPE_ADDRESS) cast_from_oop<uintptr_t>(obj) : 0);
1134     event.commit();
1135   }
1136 UNSAFE_END
1137 
1138 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread))
1139   UnsafeWrapper("Unsafe_Unpark");
1140   Parker* p = NULL;
1141   if (jthread != NULL) {
1142     oop java_thread = JNIHandles::resolve_non_null(jthread);
1143     if (java_thread != NULL) {
1144       jlong lp = java_lang_Thread::park_event(java_thread);
1145       if (lp != 0) {
1146         // This cast is OK even though the jlong might have been read
1147         // non-atomically on 32bit systems, since there, one word will
1148         // always be zero anyway and the value set is always the same
1149         p = (Parker*)addr_from_java(lp);
1150       } else {
1151         // Grab lock if apparently null or using older version of library
1152         MutexLocker mu(Threads_lock);
1153         java_thread = JNIHandles::resolve_non_null(jthread);
1154         if (java_thread != NULL) {
1155           JavaThread* thr = java_lang_Thread::thread(java_thread);
1156           if (thr != NULL) {
1157             p = thr->parker();
1158             if (p != NULL) { // Bind to Java thread for next time.
1159               java_lang_Thread::set_park_event(java_thread, addr_to_java(p));
1160             }
1161           }
1162         }
1163       }
1164     }
1165   }
1166   if (p != NULL) {
1167     HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1168     p->unpark();
1169   }
1170 UNSAFE_END
1171 
1172 UNSAFE_ENTRY(jint, Unsafe_Loadavg(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem))
1173   UnsafeWrapper("Unsafe_Loadavg");
1174   const int max_nelem = 3;
1175   double la[max_nelem];
1176   jint ret;
1177 
1178   typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1179   assert(a->is_typeArray(), "must be type array");
1180 
1181   if (nelem < 0 || nelem > max_nelem || a->length() < nelem) {
1182     ThreadToNativeFromVM ttnfv(thread);
1183     throw_new(env, "ArrayIndexOutOfBoundsException");
1184     return -1;
1185   }
1186 
1187   ret = os::loadavg(la, nelem);
1188   if (ret == -1) return -1;
1189 
1190   // if successful, ret is the number of samples actually retrieved.
1191   assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1192   switch(ret) {
1193     case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1194     case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1195     case 1: a->double_at_put(0, (jdouble)la[0]); break;
1196   }
1197   return ret;
1198 UNSAFE_END
1199 
1200 
1201 /// JVM_RegisterUnsafeMethods
1202 
1203 #define ADR "J"
1204 
1205 #define LANG "Ljava/lang/"
1206 
1207 #define OBJ LANG "Object;"
1208 #define CLS LANG "Class;"
1209 #define FLD LANG "reflect/Field;"
1210 #define THR LANG "Throwable;"
1211 
1212 #define DC_Args  LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1213 #define DAC_Args CLS "[B[" OBJ
1214 
1215 #define CC (char*)  /*cast a literal from (const char*)*/
1216 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1217 
1218 #define DECLARE_GETPUTOOP(Boolean, Z) \
1219     {CC "get" #Boolean,      CC "(" OBJ "J)" #Z,       FN_PTR(Unsafe_Get##Boolean)}, \
1220     {CC "put" #Boolean,      CC "(" OBJ "J" #Z ")V",   FN_PTR(Unsafe_Set##Boolean)}, \
1221     {CC "get" #Boolean "Volatile",      CC "(" OBJ "J)" #Z,       FN_PTR(Unsafe_Get##Boolean##Volatile)}, \
1222     {CC "put" #Boolean "Volatile",      CC "(" OBJ "J" #Z ")V",   FN_PTR(Unsafe_Set##Boolean##Volatile)}
1223 
1224 
1225 #define DECLARE_GETPUTNATIVE(Byte, B) \
1226     {CC "get" #Byte,         CC "(" ADR ")" #B,       FN_PTR(Unsafe_GetNative##Byte)}, \
1227     {CC "put" #Byte,         CC "(" ADR#B ")V",       FN_PTR(Unsafe_SetNative##Byte)}
1228 
1229 
1230 
1231 static JNINativeMethod methods[] = {
1232     {CC "getObject",        CC "(" OBJ "J)" OBJ "",   FN_PTR(Unsafe_GetObject)},
1233     {CC "putObject",        CC "(" OBJ "J" OBJ ")V",  FN_PTR(Unsafe_SetObject)},
1234     {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "",   FN_PTR(Unsafe_GetObjectVolatile)},
1235     {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V",  FN_PTR(Unsafe_SetObjectVolatile)},
1236 
1237     {CC "getUncompressedObject", CC "(" ADR ")" OBJ,  FN_PTR(Unsafe_GetUncompressedObject)},
1238     {CC "getJavaMirror",         CC "(" ADR ")" CLS,  FN_PTR(Unsafe_GetJavaMirror)},
1239     {CC "getKlassPointer",       CC "(" OBJ ")" ADR,  FN_PTR(Unsafe_GetKlassPointer)},
1240 
1241     DECLARE_GETPUTOOP(Boolean, Z),
1242     DECLARE_GETPUTOOP(Byte, B),
1243     DECLARE_GETPUTOOP(Short, S),
1244     DECLARE_GETPUTOOP(Char, C),
1245     DECLARE_GETPUTOOP(Int, I),
1246     DECLARE_GETPUTOOP(Long, J),
1247     DECLARE_GETPUTOOP(Float, F),
1248     DECLARE_GETPUTOOP(Double, D),
1249 
1250     DECLARE_GETPUTNATIVE(Byte, B),
1251     DECLARE_GETPUTNATIVE(Short, S),
1252     DECLARE_GETPUTNATIVE(Char, C),
1253     DECLARE_GETPUTNATIVE(Int, I),
1254     DECLARE_GETPUTNATIVE(Long, J),
1255     DECLARE_GETPUTNATIVE(Float, F),
1256     DECLARE_GETPUTNATIVE(Double, D),
1257 
1258     {CC "getAddress",         CC "(" ADR ")" ADR,        FN_PTR(Unsafe_GetNativeAddress)},
1259     {CC "putAddress",         CC "(" ADR "" ADR ")V",    FN_PTR(Unsafe_SetNativeAddress)},
1260 
1261     {CC "allocateMemory",     CC "(J)" ADR,              FN_PTR(Unsafe_AllocateMemory)},
1262     {CC "reallocateMemory",   CC "(" ADR "J)" ADR,       FN_PTR(Unsafe_ReallocateMemory)},
1263     {CC "freeMemory",         CC "(" ADR ")V",           FN_PTR(Unsafe_FreeMemory)},
1264 
1265     {CC "objectFieldOffset",  CC "(" FLD ")J",           FN_PTR(Unsafe_ObjectFieldOffset)},
1266     {CC "staticFieldOffset",  CC "(" FLD ")J",           FN_PTR(Unsafe_StaticFieldOffset)},
1267     {CC "staticFieldBase",    CC "(" FLD ")" OBJ,        FN_PTR(Unsafe_StaticFieldBaseFromField)},
1268     {CC "ensureClassInitialized",CC "(" CLS ")V",        FN_PTR(Unsafe_EnsureClassInitialized)},
1269     {CC "arrayBaseOffset",    CC "(" CLS ")I",           FN_PTR(Unsafe_ArrayBaseOffset)},
1270     {CC "arrayIndexScale",    CC "(" CLS ")I",           FN_PTR(Unsafe_ArrayIndexScale)},
1271     {CC "addressSize",        CC "()I",                  FN_PTR(Unsafe_AddressSize)},
1272     {CC "pageSize",           CC "()I",                  FN_PTR(Unsafe_PageSize)},
1273 
1274     {CC "defineClass",        CC "(" DC_Args ")" CLS,    FN_PTR(Unsafe_DefineClass)},
1275     {CC "allocateInstance",   CC "(" CLS ")" OBJ,        FN_PTR(Unsafe_AllocateInstance)},
1276     {CC "throwException",     CC "(" THR ")V",           FN_PTR(Unsafe_ThrowException)},
1277     {CC "compareAndSwapObject", CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSwapObject)},
1278     {CC "compareAndSwapInt",  CC "(" OBJ "J""I""I"")Z",  FN_PTR(Unsafe_CompareAndSwapInt)},
1279     {CC "compareAndSwapLong", CC "(" OBJ "J""J""J"")Z",  FN_PTR(Unsafe_CompareAndSwapLong)},
1280     {CC "putOrderedObject",   CC "(" OBJ "J" OBJ ")V",   FN_PTR(Unsafe_SetOrderedObject)},
1281     {CC "putOrderedInt",      CC "(" OBJ "JI)V",         FN_PTR(Unsafe_SetOrderedInt)},
1282     {CC "putOrderedLong",     CC "(" OBJ "JJ)V",         FN_PTR(Unsafe_SetOrderedLong)},
1283     {CC "park",               CC "(ZJ)V",                FN_PTR(Unsafe_Park)},
1284     {CC "unpark",             CC "(" OBJ ")V",           FN_PTR(Unsafe_Unpark)},
1285 
1286     {CC "getLoadAverage",     CC "([DI)I",               FN_PTR(Unsafe_Loadavg)},
1287 
1288     {CC "copyMemory",         CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory)},
1289     {CC "setMemory",          CC "(" OBJ "JJB)V",        FN_PTR(Unsafe_SetMemory)},
1290 
1291     {CC "defineAnonymousClass", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass)},
1292 
1293     {CC "shouldBeInitialized",CC "(" CLS ")Z",           FN_PTR(Unsafe_ShouldBeInitialized)},
1294 
1295     {CC "loadFence",          CC "()V",                  FN_PTR(Unsafe_LoadFence)},
1296     {CC "storeFence",         CC "()V",                  FN_PTR(Unsafe_StoreFence)},
1297     {CC "fullFence",          CC "()V",                  FN_PTR(Unsafe_FullFence)},
1298 
1299     {CC "isBigEndian0",       CC "()Z",                  FN_PTR(Unsafe_isBigEndian0)},
1300     {CC "unalignedAccess0",   CC "()Z",                  FN_PTR(Unsafe_unalignedAccess0)}
1301 };
1302 
1303 #undef CC
1304 #undef FN_PTR
1305 
1306 #undef ADR
1307 #undef LANG
1308 #undef OBJ
1309 #undef CLS
1310 #undef FLD
1311 #undef THR
1312 #undef DC_Args
1313 #undef DAC_Args
1314 
1315 #undef DECLARE_GETPUTOOP
1316 #undef DECLARE_GETPUTNATIVE
1317 
1318 
1319 // This one function is exported, used by NativeLookup.
1320 // The Unsafe_xxx functions above are called only from the interpreter.
1321 // The optimizer looks at names and signatures to recognize
1322 // individual functions.
1323 
1324 JVM_ENTRY(void, JVM_RegisterUnsafeMethods(JNIEnv *env, jclass unsafeclass))
1325   UnsafeWrapper("JVM_RegisterUnsafeMethods");
1326   {
1327     ThreadToNativeFromVM ttnfv(thread);
1328 
1329     int ok = env->RegisterNatives(unsafeclass, methods, sizeof(methods)/sizeof(JNINativeMethod));
1330     guarantee(ok == 0, "register unsafe natives");
1331   }
1332 JVM_END