1 /*
   2  * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.misc;
  27 
  28 import jdk.internal.vm.annotation.ForceInline;
  29 import jdk.internal.misc.VM;
  30 import jdk.internal.ref.Cleaner;
  31 import jdk.internal.reflect.CallerSensitive;
  32 import jdk.internal.reflect.Reflection;
  33 import sun.nio.ch.DirectBuffer;
  34 
  35 import java.lang.reflect.Field;
  36 import java.util.Set;
  37 
  38 
  39 /**
  40  * A collection of methods for performing low-level, unsafe operations.
  41  * Although the class and all methods are public, use of this class is
  42  * limited because only trusted code can obtain instances of it.
  43  *
  44  * <em>Note:</em> It is the resposibility of the caller to make sure
  45  * arguments are checked before methods of this class are
  46  * called. While some rudimentary checks are performed on the input,
  47  * the checks are best effort and when performance is an overriding
  48  * priority, as when methods of this class are optimized by the
  49  * runtime compiler, some or all checks (if any) may be elided. Hence,
  50  * the caller must not rely on the checks and corresponding
  51  * exceptions!
  52  *
  53  * @author John R. Rose
  54  * @see #getUnsafe
  55  */
  56 
  57 public final class Unsafe {
  58 
  59     static {
  60         Reflection.registerMethodsToFilter(Unsafe.class, Set.of("getUnsafe"));
  61     }
  62 
  63     private Unsafe() {}
  64 
  65     private static final Unsafe theUnsafe = new Unsafe();
  66     private static final jdk.internal.misc.Unsafe theInternalUnsafe = jdk.internal.misc.Unsafe.getUnsafe();
  67 
  68     /**
  69      * Provides the caller with the capability of performing unsafe
  70      * operations.
  71      *
  72      * <p>The returned {@code Unsafe} object should be carefully guarded
  73      * by the caller, since it can be used to read and write data at arbitrary
  74      * memory addresses.  It must never be passed to untrusted code.
  75      *
  76      * <p>Most methods in this class are very low-level, and correspond to a
  77      * small number of hardware instructions (on typical machines).  Compilers
  78      * are encouraged to optimize these methods accordingly.
  79      *
  80      * <p>Here is a suggested idiom for using unsafe operations:
  81      *
  82      * <pre> {@code
  83      * class MyTrustedClass {
  84      *   private static final Unsafe unsafe = Unsafe.getUnsafe();
  85      *   ...
  86      *   private long myCountAddress = ...;
  87      *   public int getCount() { return unsafe.getByte(myCountAddress); }
  88      * }}</pre>
  89      *
  90      * (It may assist compilers to make the local variable {@code final}.)
  91      *
  92      * @throws  SecurityException if the class loader of the caller
  93      *          class is not in the system domain in which all permissions
  94      *          are granted.
  95      */
  96     @CallerSensitive
  97     public static Unsafe getUnsafe() {
  98         Class<?> caller = Reflection.getCallerClass();
  99         if (!VM.isSystemDomainLoader(caller.getClassLoader()))
 100             throw new SecurityException("Unsafe");
 101         return theUnsafe;
 102     }
 103 
 104     /// peek and poke operations
 105     /// (compilers should optimize these to memory ops)
 106 
 107     // These work on object fields in the Java heap.
 108     // They will not work on elements of packed arrays.
 109 
 110     /**
 111      * Fetches a value from a given Java variable.
 112      * More specifically, fetches a field or array element within the given
 113      * object {@code o} at the given offset, or (if {@code o} is null)
 114      * from the memory address whose numerical value is the given offset.
 115      * <p>
 116      * The results are undefined unless one of the following cases is true:
 117      * <ul>
 118      * <li>The offset was obtained from {@link #objectFieldOffset} on
 119      * the {@link java.lang.reflect.Field} of some Java field and the object
 120      * referred to by {@code o} is of a class compatible with that
 121      * field's class.
 122      *
 123      * <li>The offset and object reference {@code o} (either null or
 124      * non-null) were both obtained via {@link #staticFieldOffset}
 125      * and {@link #staticFieldBase} (respectively) from the
 126      * reflective {@link Field} representation of some Java field.
 127      *
 128      * <li>The object referred to by {@code o} is an array, and the offset
 129      * is an integer of the form {@code B+N*S}, where {@code N} is
 130      * a valid index into the array, and {@code B} and {@code S} are
 131      * the values obtained by {@link #arrayBaseOffset} and {@link
 132      * #arrayIndexScale} (respectively) from the array's class.  The value
 133      * referred to is the {@code N}<em>th</em> element of the array.
 134      *
 135      * </ul>
 136      * <p>
 137      * If one of the above cases is true, the call references a specific Java
 138      * variable (field or array element).  However, the results are undefined
 139      * if that variable is not in fact of the type returned by this method.
 140      * <p>
 141      * This method refers to a variable by means of two parameters, and so
 142      * it provides (in effect) a <em>double-register</em> addressing mode
 143      * for Java variables.  When the object reference is null, this method
 144      * uses its offset as an absolute address.  This is similar in operation
 145      * to methods such as {@link #getInt(long)}, which provide (in effect) a
 146      * <em>single-register</em> addressing mode for non-Java variables.
 147      * However, because Java variables may have a different layout in memory
 148      * from non-Java variables, programmers should not assume that these
 149      * two addressing modes are ever equivalent.  Also, programmers should
 150      * remember that offsets from the double-register addressing mode cannot
 151      * be portably confused with longs used in the single-register addressing
 152      * mode.
 153      *
 154      * @param o Java heap object in which the variable resides, if any, else
 155      *        null
 156      * @param offset indication of where the variable resides in a Java heap
 157      *        object, if any, else a memory address locating the variable
 158      *        statically
 159      * @return the value fetched from the indicated Java variable
 160      * @throws RuntimeException No defined exceptions are thrown, not even
 161      *         {@link NullPointerException}
 162      */
 163     @ForceInline
 164     public int getInt(Object o, long offset) {
 165         return theInternalUnsafe.getInt(o, offset);
 166     }
 167 
 168     /**
 169      * Stores a value into a given Java variable.
 170      * <p>
 171      * The first two parameters are interpreted exactly as with
 172      * {@link #getInt(Object, long)} to refer to a specific
 173      * Java variable (field or array element).  The given value
 174      * is stored into that variable.
 175      * <p>
 176      * The variable must be of the same type as the method
 177      * parameter {@code x}.
 178      *
 179      * @param o Java heap object in which the variable resides, if any, else
 180      *        null
 181      * @param offset indication of where the variable resides in a Java heap
 182      *        object, if any, else a memory address locating the variable
 183      *        statically
 184      * @param x the value to store into the indicated Java variable
 185      * @throws RuntimeException No defined exceptions are thrown, not even
 186      *         {@link NullPointerException}
 187      */
 188     @ForceInline
 189     public void putInt(Object o, long offset, int x) {
 190         theInternalUnsafe.putInt(o, offset, x);
 191     }
 192 
 193     /**
 194      * Fetches a reference value from a given Java variable.
 195      * @see #getInt(Object, long)
 196      */
 197     @ForceInline
 198     public Object getObject(Object o, long offset) {
 199         return theInternalUnsafe.getReference(o, offset);
 200     }
 201 
 202     /**
 203      * Stores a reference value into a given Java variable.
 204      * <p>
 205      * Unless the reference {@code x} being stored is either null
 206      * or matches the field type, the results are undefined.
 207      * If the reference {@code o} is non-null, card marks or
 208      * other store barriers for that object (if the VM requires them)
 209      * are updated.
 210      * @see #putInt(Object, long, int)
 211      */
 212     @ForceInline
 213     public void putObject(Object o, long offset, Object x) {
 214         theInternalUnsafe.putReference(o, offset, x);
 215     }
 216 
 217     /** @see #getInt(Object, long) */
 218     @ForceInline
 219     public boolean getBoolean(Object o, long offset) {
 220         return theInternalUnsafe.getBoolean(o, offset);
 221     }
 222 
 223     /** @see #putInt(Object, long, int) */
 224     @ForceInline
 225     public void putBoolean(Object o, long offset, boolean x) {
 226         theInternalUnsafe.putBoolean(o, offset, x);
 227     }
 228 
 229     /** @see #getInt(Object, long) */
 230     @ForceInline
 231     public byte getByte(Object o, long offset) {
 232         return theInternalUnsafe.getByte(o, offset);
 233     }
 234 
 235     /** @see #putInt(Object, long, int) */
 236     @ForceInline
 237     public void putByte(Object o, long offset, byte x) {
 238         theInternalUnsafe.putByte(o, offset, x);
 239     }
 240 
 241     /** @see #getInt(Object, long) */
 242     @ForceInline
 243     public short getShort(Object o, long offset) {
 244         return theInternalUnsafe.getShort(o, offset);
 245     }
 246 
 247     /** @see #putInt(Object, long, int) */
 248     @ForceInline
 249     public void putShort(Object o, long offset, short x) {
 250         theInternalUnsafe.putShort(o, offset, x);
 251     }
 252 
 253     /** @see #getInt(Object, long) */
 254     @ForceInline
 255     public char getChar(Object o, long offset) {
 256         return theInternalUnsafe.getChar(o, offset);
 257     }
 258 
 259     /** @see #putInt(Object, long, int) */
 260     @ForceInline
 261     public void putChar(Object o, long offset, char x) {
 262         theInternalUnsafe.putChar(o, offset, x);
 263     }
 264 
 265     /** @see #getInt(Object, long) */
 266     @ForceInline
 267     public long getLong(Object o, long offset) {
 268         return theInternalUnsafe.getLong(o, offset);
 269     }
 270 
 271     /** @see #putInt(Object, long, int) */
 272     @ForceInline
 273     public void putLong(Object o, long offset, long x) {
 274         theInternalUnsafe.putLong(o, offset, x);
 275     }
 276 
 277     /** @see #getInt(Object, long) */
 278     @ForceInline
 279     public float getFloat(Object o, long offset) {
 280         return theInternalUnsafe.getFloat(o, offset);
 281     }
 282 
 283     /** @see #putInt(Object, long, int) */
 284     @ForceInline
 285     public void putFloat(Object o, long offset, float x) {
 286         theInternalUnsafe.putFloat(o, offset, x);
 287     }
 288 
 289     /** @see #getInt(Object, long) */
 290     @ForceInline
 291     public double getDouble(Object o, long offset) {
 292         return theInternalUnsafe.getDouble(o, offset);
 293     }
 294 
 295     /** @see #putInt(Object, long, int) */
 296     @ForceInline
 297     public void putDouble(Object o, long offset, double x) {
 298         theInternalUnsafe.putDouble(o, offset, x);
 299     }
 300 
 301     // These work on values in the C heap.
 302 
 303     /**
 304      * Fetches a value from a given memory address.  If the address is zero, or
 305      * does not point into a block obtained from {@link #allocateMemory}, the
 306      * results are undefined.
 307      *
 308      * @see #allocateMemory
 309      */
 310     @ForceInline
 311     public byte getByte(long address) {
 312         return theInternalUnsafe.getByte(address);
 313     }
 314 
 315     /**
 316      * Stores a value into a given memory address.  If the address is zero, or
 317      * does not point into a block obtained from {@link #allocateMemory}, the
 318      * results are undefined.
 319      *
 320      * @see #getByte(long)
 321      */
 322     @ForceInline
 323     public void putByte(long address, byte x) {
 324         theInternalUnsafe.putByte(address, x);
 325     }
 326 
 327     /** @see #getByte(long) */
 328     @ForceInline
 329     public short getShort(long address) {
 330         return theInternalUnsafe.getShort(address);
 331     }
 332 
 333     /** @see #putByte(long, byte) */
 334     @ForceInline
 335     public void putShort(long address, short x) {
 336         theInternalUnsafe.putShort(address, x);
 337     }
 338 
 339     /** @see #getByte(long) */
 340     @ForceInline
 341     public char getChar(long address) {
 342         return theInternalUnsafe.getChar(address);
 343     }
 344 
 345     /** @see #putByte(long, byte) */
 346     @ForceInline
 347     public void putChar(long address, char x) {
 348         theInternalUnsafe.putChar(address, x);
 349     }
 350 
 351     /** @see #getByte(long) */
 352     @ForceInline
 353     public int getInt(long address) {
 354         return theInternalUnsafe.getInt(address);
 355     }
 356 
 357     /** @see #putByte(long, byte) */
 358     @ForceInline
 359     public void putInt(long address, int x) {
 360         theInternalUnsafe.putInt(address, x);
 361     }
 362 
 363     /** @see #getByte(long) */
 364     @ForceInline
 365     public long getLong(long address) {
 366         return theInternalUnsafe.getLong(address);
 367     }
 368 
 369     /** @see #putByte(long, byte) */
 370     @ForceInline
 371     public void putLong(long address, long x) {
 372         theInternalUnsafe.putLong(address, x);
 373     }
 374 
 375     /** @see #getByte(long) */
 376     @ForceInline
 377     public float getFloat(long address) {
 378         return theInternalUnsafe.getFloat(address);
 379     }
 380 
 381     /** @see #putByte(long, byte) */
 382     @ForceInline
 383     public void putFloat(long address, float x) {
 384         theInternalUnsafe.putFloat(address, x);
 385     }
 386 
 387     /** @see #getByte(long) */
 388     @ForceInline
 389     public double getDouble(long address) {
 390         return theInternalUnsafe.getDouble(address);
 391     }
 392 
 393     /** @see #putByte(long, byte) */
 394     @ForceInline
 395     public void putDouble(long address, double x) {
 396         theInternalUnsafe.putDouble(address, x);
 397     }
 398 
 399 
 400     /**
 401      * Fetches a native pointer from a given memory address.  If the address is
 402      * zero, or does not point into a block obtained from {@link
 403      * #allocateMemory}, the results are undefined.
 404      *
 405      * <p>If the native pointer is less than 64 bits wide, it is extended as
 406      * an unsigned number to a Java long.  The pointer may be indexed by any
 407      * given byte offset, simply by adding that offset (as a simple integer) to
 408      * the long representing the pointer.  The number of bytes actually read
 409      * from the target address may be determined by consulting {@link
 410      * #addressSize}.
 411      *
 412      * @see #allocateMemory
 413      */
 414     @ForceInline
 415     public long getAddress(long address) {
 416         return theInternalUnsafe.getAddress(address);
 417     }
 418 
 419     /**
 420      * Stores a native pointer into a given memory address.  If the address is
 421      * zero, or does not point into a block obtained from {@link
 422      * #allocateMemory}, the results are undefined.
 423      *
 424      * <p>The number of bytes actually written at the target address may be
 425      * determined by consulting {@link #addressSize}.
 426      *
 427      * @see #getAddress(long)
 428      */
 429     @ForceInline
 430     public void putAddress(long address, long x) {
 431         theInternalUnsafe.putAddress(address, x);
 432     }
 433 
 434 
 435     /// wrappers for malloc, realloc, free:
 436 
 437     /**
 438      * Allocates a new block of native memory, of the given size in bytes.  The
 439      * contents of the memory are uninitialized; they will generally be
 440      * garbage.  The resulting native pointer will never be zero, and will be
 441      * aligned for all value types.  Dispose of this memory by calling {@link
 442      * #freeMemory}, or resize it with {@link #reallocateMemory}.
 443      *
 444      * <em>Note:</em> It is the resposibility of the caller to make
 445      * sure arguments are checked before the methods are called. While
 446      * some rudimentary checks are performed on the input, the checks
 447      * are best effort and when performance is an overriding priority,
 448      * as when methods of this class are optimized by the runtime
 449      * compiler, some or all checks (if any) may be elided. Hence, the
 450      * caller must not rely on the checks and corresponding
 451      * exceptions!
 452      *
 453      * @throws RuntimeException if the size is negative or too large
 454      *         for the native size_t type
 455      *
 456      * @throws OutOfMemoryError if the allocation is refused by the system
 457      *
 458      * @see #getByte(long)
 459      * @see #putByte(long, byte)
 460      */
 461     @ForceInline
 462     public long allocateMemory(long bytes) {
 463         return theInternalUnsafe.allocateMemory(bytes);
 464     }
 465 
 466     /**
 467      * Resizes a new block of native memory, to the given size in bytes.  The
 468      * contents of the new block past the size of the old block are
 469      * uninitialized; they will generally be garbage.  The resulting native
 470      * pointer will be zero if and only if the requested size is zero.  The
 471      * resulting native pointer will be aligned for all value types.  Dispose
 472      * of this memory by calling {@link #freeMemory}, or resize it with {@link
 473      * #reallocateMemory}.  The address passed to this method may be null, in
 474      * which case an allocation will be performed.
 475      *
 476      * <em>Note:</em> It is the resposibility of the caller to make
 477      * sure arguments are checked before the methods are called. While
 478      * some rudimentary checks are performed on the input, the checks
 479      * are best effort and when performance is an overriding priority,
 480      * as when methods of this class are optimized by the runtime
 481      * compiler, some or all checks (if any) may be elided. Hence, the
 482      * caller must not rely on the checks and corresponding
 483      * exceptions!
 484      *
 485      * @throws RuntimeException if the size is negative or too large
 486      *         for the native size_t type
 487      *
 488      * @throws OutOfMemoryError if the allocation is refused by the system
 489      *
 490      * @see #allocateMemory
 491      */
 492     @ForceInline
 493     public long reallocateMemory(long address, long bytes) {
 494         return theInternalUnsafe.reallocateMemory(address, bytes);
 495     }
 496 
 497     /**
 498      * Sets all bytes in a given block of memory to a fixed value
 499      * (usually zero).
 500      *
 501      * <p>This method determines a block's base address by means of two parameters,
 502      * and so it provides (in effect) a <em>double-register</em> addressing mode,
 503      * as discussed in {@link #getInt(Object,long)}.  When the object reference is null,
 504      * the offset supplies an absolute base address.
 505      *
 506      * <p>The stores are in coherent (atomic) units of a size determined
 507      * by the address and length parameters.  If the effective address and
 508      * length are all even modulo 8, the stores take place in 'long' units.
 509      * If the effective address and length are (resp.) even modulo 4 or 2,
 510      * the stores take place in units of 'int' or 'short'.
 511      *
 512      * <em>Note:</em> It is the resposibility of the caller to make
 513      * sure arguments are checked before the methods are called. While
 514      * some rudimentary checks are performed on the input, the checks
 515      * are best effort and when performance is an overriding priority,
 516      * as when methods of this class are optimized by the runtime
 517      * compiler, some or all checks (if any) may be elided. Hence, the
 518      * caller must not rely on the checks and corresponding
 519      * exceptions!
 520      *
 521      * @throws RuntimeException if any of the arguments is invalid
 522      *
 523      * @since 1.7
 524      */
 525     @ForceInline
 526     public void setMemory(Object o, long offset, long bytes, byte value) {
 527         theInternalUnsafe.setMemory(o, offset, bytes, value);
 528     }
 529 
 530     /**
 531      * Sets all bytes in a given block of memory to a fixed value
 532      * (usually zero).  This provides a <em>single-register</em> addressing mode,
 533      * as discussed in {@link #getInt(Object,long)}.
 534      *
 535      * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
 536      */
 537     @ForceInline
 538     public void setMemory(long address, long bytes, byte value) {
 539         theInternalUnsafe.setMemory(address, bytes, value);
 540     }
 541 
 542     /**
 543      * Sets all bytes in a given block of memory to a copy of another
 544      * block.
 545      *
 546      * <p>This method determines each block's base address by means of two parameters,
 547      * and so it provides (in effect) a <em>double-register</em> addressing mode,
 548      * as discussed in {@link #getInt(Object,long)}.  When the object reference is null,
 549      * the offset supplies an absolute base address.
 550      *
 551      * <p>The transfers are in coherent (atomic) units of a size determined
 552      * by the address and length parameters.  If the effective addresses and
 553      * length are all even modulo 8, the transfer takes place in 'long' units.
 554      * If the effective addresses and length are (resp.) even modulo 4 or 2,
 555      * the transfer takes place in units of 'int' or 'short'.
 556      *
 557      * <em>Note:</em> It is the resposibility of the caller to make
 558      * sure arguments are checked before the methods are called. While
 559      * some rudimentary checks are performed on the input, the checks
 560      * are best effort and when performance is an overriding priority,
 561      * as when methods of this class are optimized by the runtime
 562      * compiler, some or all checks (if any) may be elided. Hence, the
 563      * caller must not rely on the checks and corresponding
 564      * exceptions!
 565      *
 566      * @throws RuntimeException if any of the arguments is invalid
 567      *
 568      * @since 1.7
 569      */
 570     @ForceInline
 571     public void copyMemory(Object srcBase, long srcOffset,
 572                            Object destBase, long destOffset,
 573                            long bytes) {
 574         theInternalUnsafe.copyMemory(srcBase, srcOffset, destBase, destOffset, bytes);
 575     }
 576 
 577     /**
 578      * Sets all bytes in a given block of memory to a copy of another
 579      * block.  This provides a <em>single-register</em> addressing mode,
 580      * as discussed in {@link #getInt(Object,long)}.
 581      *
 582      * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
 583      */
 584     @ForceInline
 585     public void copyMemory(long srcAddress, long destAddress, long bytes) {
 586         theInternalUnsafe.copyMemory(srcAddress, destAddress, bytes);
 587     }
 588 
 589     /**
 590      * Disposes of a block of native memory, as obtained from {@link
 591      * #allocateMemory} or {@link #reallocateMemory}.  The address passed to
 592      * this method may be null, in which case no action is taken.
 593      *
 594      * <em>Note:</em> It is the resposibility of the caller to make
 595      * sure arguments are checked before the methods are called. While
 596      * some rudimentary checks are performed on the input, the checks
 597      * are best effort and when performance is an overriding priority,
 598      * as when methods of this class are optimized by the runtime
 599      * compiler, some or all checks (if any) may be elided. Hence, the
 600      * caller must not rely on the checks and corresponding
 601      * exceptions!
 602      *
 603      * @throws RuntimeException if any of the arguments is invalid
 604      *
 605      * @see #allocateMemory
 606      */
 607     @ForceInline
 608     public void freeMemory(long address) {
 609         theInternalUnsafe.freeMemory(address);
 610     }
 611 
 612     /// random queries
 613 
 614     /**
 615      * This constant differs from all results that will ever be returned from
 616      * {@link #staticFieldOffset}, {@link #objectFieldOffset},
 617      * or {@link #arrayBaseOffset}.
 618      */
 619     public static final int INVALID_FIELD_OFFSET = jdk.internal.misc.Unsafe.INVALID_FIELD_OFFSET;
 620 
 621     /**
 622      * Reports the location of a given field in the storage allocation of its
 623      * class.  Do not expect to perform any sort of arithmetic on this offset;
 624      * it is just a cookie which is passed to the unsafe heap memory accessors.
 625      *
 626      * <p>Any given field will always have the same offset and base, and no
 627      * two distinct fields of the same class will ever have the same offset
 628      * and base.
 629      *
 630      * <p>As of 1.4.1, offsets for fields are represented as long values,
 631      * although the Sun JVM does not use the most significant 32 bits.
 632      * However, JVM implementations which store static fields at absolute
 633      * addresses can use long offsets and null base pointers to express
 634      * the field locations in a form usable by {@link #getInt(Object,long)}.
 635      * Therefore, code which will be ported to such JVMs on 64-bit platforms
 636      * must preserve all bits of static field offsets.
 637      * @see #getInt(Object, long)
 638      */
 639     @ForceInline
 640     public long objectFieldOffset(Field f) {
 641         return theInternalUnsafe.objectFieldOffset(f);
 642     }
 643 
 644     /**
 645      * Reports the location of a given static field, in conjunction with {@link
 646      * #staticFieldBase}.
 647      * <p>Do not expect to perform any sort of arithmetic on this offset;
 648      * it is just a cookie which is passed to the unsafe heap memory accessors.
 649      *
 650      * <p>Any given field will always have the same offset, and no two distinct
 651      * fields of the same class will ever have the same offset.
 652      *
 653      * <p>As of 1.4.1, offsets for fields are represented as long values,
 654      * although the Sun JVM does not use the most significant 32 bits.
 655      * It is hard to imagine a JVM technology which needs more than
 656      * a few bits to encode an offset within a non-array object,
 657      * However, for consistency with other methods in this class,
 658      * this method reports its result as a long value.
 659      * @see #getInt(Object, long)
 660      */
 661     @ForceInline
 662     public long staticFieldOffset(Field f) {
 663         return theInternalUnsafe.staticFieldOffset(f);
 664     }
 665 
 666     /**
 667      * Reports the location of a given static field, in conjunction with {@link
 668      * #staticFieldOffset}.
 669      * <p>Fetch the base "Object", if any, with which static fields of the
 670      * given class can be accessed via methods like {@link #getInt(Object,
 671      * long)}.  This value may be null.  This value may refer to an object
 672      * which is a "cookie", not guaranteed to be a real Object, and it should
 673      * not be used in any way except as argument to the get and put routines in
 674      * this class.
 675      */
 676     @ForceInline
 677     public Object staticFieldBase(Field f) {
 678         return theInternalUnsafe.staticFieldBase(f);
 679     }
 680 
 681     /**
 682      * Detects if the given class may need to be initialized. This is often
 683      * needed in conjunction with obtaining the static field base of a
 684      * class.
 685      * @return false only if a call to {@code ensureClassInitialized} would have no effect
 686      */
 687     @ForceInline
 688     public boolean shouldBeInitialized(Class<?> c) {
 689         return theInternalUnsafe.shouldBeInitialized(c);
 690     }
 691 
 692     /**
 693      * Ensures the given class has been initialized. This is often
 694      * needed in conjunction with obtaining the static field base of a
 695      * class.
 696      */
 697     @ForceInline
 698     public void ensureClassInitialized(Class<?> c) {
 699         theInternalUnsafe.ensureClassInitialized(c);
 700     }
 701 
 702     /**
 703      * Reports the offset of the first element in the storage allocation of a
 704      * given array class.  If {@link #arrayIndexScale} returns a non-zero value
 705      * for the same class, you may use that scale factor, together with this
 706      * base offset, to form new offsets to access elements of arrays of the
 707      * given class.
 708      *
 709      * @see #getInt(Object, long)
 710      * @see #putInt(Object, long, int)
 711      */
 712     @ForceInline
 713     public int arrayBaseOffset(Class<?> arrayClass) {
 714         return theInternalUnsafe.arrayBaseOffset(arrayClass);
 715     }
 716 
 717     /** The value of {@code arrayBaseOffset(boolean[].class)} */
 718     public static final int ARRAY_BOOLEAN_BASE_OFFSET = jdk.internal.misc.Unsafe.ARRAY_BOOLEAN_BASE_OFFSET;
 719 
 720     /** The value of {@code arrayBaseOffset(byte[].class)} */
 721     public static final int ARRAY_BYTE_BASE_OFFSET = jdk.internal.misc.Unsafe.ARRAY_BYTE_BASE_OFFSET;
 722 
 723     /** The value of {@code arrayBaseOffset(short[].class)} */
 724     public static final int ARRAY_SHORT_BASE_OFFSET = jdk.internal.misc.Unsafe.ARRAY_SHORT_BASE_OFFSET;
 725 
 726     /** The value of {@code arrayBaseOffset(char[].class)} */
 727     public static final int ARRAY_CHAR_BASE_OFFSET = jdk.internal.misc.Unsafe.ARRAY_CHAR_BASE_OFFSET;
 728 
 729     /** The value of {@code arrayBaseOffset(int[].class)} */
 730     public static final int ARRAY_INT_BASE_OFFSET = jdk.internal.misc.Unsafe.ARRAY_INT_BASE_OFFSET;
 731 
 732     /** The value of {@code arrayBaseOffset(long[].class)} */
 733     public static final int ARRAY_LONG_BASE_OFFSET = jdk.internal.misc.Unsafe.ARRAY_LONG_BASE_OFFSET;
 734 
 735     /** The value of {@code arrayBaseOffset(float[].class)} */
 736     public static final int ARRAY_FLOAT_BASE_OFFSET = jdk.internal.misc.Unsafe.ARRAY_FLOAT_BASE_OFFSET;
 737 
 738     /** The value of {@code arrayBaseOffset(double[].class)} */
 739     public static final int ARRAY_DOUBLE_BASE_OFFSET = jdk.internal.misc.Unsafe.ARRAY_DOUBLE_BASE_OFFSET;
 740 
 741     /** The value of {@code arrayBaseOffset(Object[].class)} */
 742     public static final int ARRAY_OBJECT_BASE_OFFSET = jdk.internal.misc.Unsafe.ARRAY_OBJECT_BASE_OFFSET;
 743 
 744     /**
 745      * Reports the scale factor for addressing elements in the storage
 746      * allocation of a given array class.  However, arrays of "narrow" types
 747      * will generally not work properly with accessors like {@link
 748      * #getByte(Object, long)}, so the scale factor for such classes is reported
 749      * as zero.
 750      *
 751      * @see #arrayBaseOffset
 752      * @see #getInt(Object, long)
 753      * @see #putInt(Object, long, int)
 754      */
 755     @ForceInline
 756     public int arrayIndexScale(Class<?> arrayClass) {
 757         return theInternalUnsafe.arrayIndexScale(arrayClass);
 758     }
 759 
 760     /** The value of {@code arrayIndexScale(boolean[].class)} */
 761     public static final int ARRAY_BOOLEAN_INDEX_SCALE = jdk.internal.misc.Unsafe.ARRAY_BOOLEAN_INDEX_SCALE;
 762 
 763     /** The value of {@code arrayIndexScale(byte[].class)} */
 764     public static final int ARRAY_BYTE_INDEX_SCALE = jdk.internal.misc.Unsafe.ARRAY_BYTE_INDEX_SCALE;
 765 
 766     /** The value of {@code arrayIndexScale(short[].class)} */
 767     public static final int ARRAY_SHORT_INDEX_SCALE = jdk.internal.misc.Unsafe.ARRAY_SHORT_INDEX_SCALE;
 768 
 769     /** The value of {@code arrayIndexScale(char[].class)} */
 770     public static final int ARRAY_CHAR_INDEX_SCALE = jdk.internal.misc.Unsafe.ARRAY_CHAR_INDEX_SCALE;
 771 
 772     /** The value of {@code arrayIndexScale(int[].class)} */
 773     public static final int ARRAY_INT_INDEX_SCALE = jdk.internal.misc.Unsafe.ARRAY_INT_INDEX_SCALE;
 774 
 775     /** The value of {@code arrayIndexScale(long[].class)} */
 776     public static final int ARRAY_LONG_INDEX_SCALE = jdk.internal.misc.Unsafe.ARRAY_LONG_INDEX_SCALE;
 777 
 778     /** The value of {@code arrayIndexScale(float[].class)} */
 779     public static final int ARRAY_FLOAT_INDEX_SCALE = jdk.internal.misc.Unsafe.ARRAY_FLOAT_INDEX_SCALE;
 780 
 781     /** The value of {@code arrayIndexScale(double[].class)} */
 782     public static final int ARRAY_DOUBLE_INDEX_SCALE = jdk.internal.misc.Unsafe.ARRAY_DOUBLE_INDEX_SCALE;
 783 
 784     /** The value of {@code arrayIndexScale(Object[].class)} */
 785     public static final int ARRAY_OBJECT_INDEX_SCALE = jdk.internal.misc.Unsafe.ARRAY_OBJECT_INDEX_SCALE;
 786 
 787     /**
 788      * Reports the size in bytes of a native pointer, as stored via {@link
 789      * #putAddress}.  This value will be either 4 or 8.  Note that the sizes of
 790      * other primitive types (as stored in native memory blocks) is determined
 791      * fully by their information content.
 792      */
 793     @ForceInline
 794     public int addressSize() {
 795         return theInternalUnsafe.addressSize();
 796     }
 797 
 798     /** The value of {@code addressSize()} */
 799     public static final int ADDRESS_SIZE = theInternalUnsafe.addressSize();
 800 
 801     /**
 802      * Reports the size in bytes of a native memory page (whatever that is).
 803      * This value will always be a power of two.
 804      */
 805     @ForceInline
 806     public int pageSize() {
 807         return theInternalUnsafe.pageSize();
 808     }
 809 
 810 
 811     /// random trusted operations from JNI:
 812 
 813     /**
 814      * Defines a class but does not make it known to the class loader or system dictionary.
 815      * <p>
 816      * For each CP entry, the corresponding CP patch must either be null or have
 817      * the a format that matches its tag:
 818      * <ul>
 819      * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang
 820      * <li>Utf8: a string (must have suitable syntax if used as signature or name)
 821      * <li>Class: any java.lang.Class object
 822      * <li>String: any object (not just a java.lang.String)
 823      * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments
 824      * </ul>
 825      * @param hostClass context for linkage, access control, protection domain, and class loader
 826      * @param data      bytes of a class file
 827      * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data
 828      */
 829     @ForceInline
 830     public Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches) {
 831         return theInternalUnsafe.defineAnonymousClass(hostClass, data, cpPatches);
 832     }
 833 
 834     /**
 835      * Allocates an instance but does not run any constructor.
 836      * Initializes the class if it has not yet been.
 837      */
 838     @ForceInline
 839     public Object allocateInstance(Class<?> cls)
 840         throws InstantiationException {
 841         return theInternalUnsafe.allocateInstance(cls);
 842     }
 843 
 844     /** Throws the exception without telling the verifier. */
 845     @ForceInline
 846     public void throwException(Throwable ee) {
 847         theInternalUnsafe.throwException(ee);
 848     }
 849 
 850     /**
 851      * Atomically updates Java variable to {@code x} if it is currently
 852      * holding {@code expected}.
 853      *
 854      * <p>This operation has memory semantics of a {@code volatile} read
 855      * and write.  Corresponds to C11 atomic_compare_exchange_strong.
 856      *
 857      * @return {@code true} if successful
 858      */
 859     @ForceInline
 860     public final boolean compareAndSwapObject(Object o, long offset,
 861                                               Object expected,
 862                                               Object x) {
 863         return theInternalUnsafe.compareAndSetReference(o, offset, expected, x);
 864     }
 865 
 866     /**
 867      * Atomically updates Java variable to {@code x} if it is currently
 868      * holding {@code expected}.
 869      *
 870      * <p>This operation has memory semantics of a {@code volatile} read
 871      * and write.  Corresponds to C11 atomic_compare_exchange_strong.
 872      *
 873      * @return {@code true} if successful
 874      */
 875     @ForceInline
 876     public final boolean compareAndSwapInt(Object o, long offset,
 877                                            int expected,
 878                                            int x) {
 879         return theInternalUnsafe.compareAndSetInt(o, offset, expected, x);
 880     }
 881 
 882     /**
 883      * Atomically updates Java variable to {@code x} if it is currently
 884      * holding {@code expected}.
 885      *
 886      * <p>This operation has memory semantics of a {@code volatile} read
 887      * and write.  Corresponds to C11 atomic_compare_exchange_strong.
 888      *
 889      * @return {@code true} if successful
 890      */
 891     @ForceInline
 892     public final boolean compareAndSwapLong(Object o, long offset,
 893                                             long expected,
 894                                             long x) {
 895         return theInternalUnsafe.compareAndSetLong(o, offset, expected, x);
 896     }
 897 
 898     /**
 899      * Fetches a reference value from a given Java variable, with volatile
 900      * load semantics. Otherwise identical to {@link #getObject(Object, long)}
 901      */
 902     @ForceInline
 903     public Object getObjectVolatile(Object o, long offset) {
 904         return theInternalUnsafe.getReferenceVolatile(o, offset);
 905     }
 906 
 907     /**
 908      * Stores a reference value into a given Java variable, with
 909      * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)}
 910      */
 911     @ForceInline
 912     public void putObjectVolatile(Object o, long offset, Object x) {
 913         theInternalUnsafe.putReferenceVolatile(o, offset, x);
 914     }
 915 
 916     /** Volatile version of {@link #getInt(Object, long)}  */
 917     @ForceInline
 918     public int getIntVolatile(Object o, long offset) {
 919         return theInternalUnsafe.getIntVolatile(o, offset);
 920     }
 921 
 922     /** Volatile version of {@link #putInt(Object, long, int)}  */
 923     @ForceInline
 924     public void putIntVolatile(Object o, long offset, int x) {
 925         theInternalUnsafe.putIntVolatile(o, offset, x);
 926     }
 927 
 928     /** Volatile version of {@link #getBoolean(Object, long)}  */
 929     @ForceInline
 930     public boolean getBooleanVolatile(Object o, long offset) {
 931         return theInternalUnsafe.getBooleanVolatile(o, offset);
 932     }
 933 
 934     /** Volatile version of {@link #putBoolean(Object, long, boolean)}  */
 935     @ForceInline
 936     public void putBooleanVolatile(Object o, long offset, boolean x) {
 937         theInternalUnsafe.putBooleanVolatile(o, offset, x);
 938     }
 939 
 940     /** Volatile version of {@link #getByte(Object, long)}  */
 941     @ForceInline
 942     public byte getByteVolatile(Object o, long offset) {
 943         return theInternalUnsafe.getByteVolatile(o, offset);
 944     }
 945 
 946     /** Volatile version of {@link #putByte(Object, long, byte)}  */
 947     @ForceInline
 948     public void putByteVolatile(Object o, long offset, byte x) {
 949         theInternalUnsafe.putByteVolatile(o, offset, x);
 950     }
 951 
 952     /** Volatile version of {@link #getShort(Object, long)}  */
 953     @ForceInline
 954     public short getShortVolatile(Object o, long offset) {
 955         return theInternalUnsafe.getShortVolatile(o, offset);
 956     }
 957 
 958     /** Volatile version of {@link #putShort(Object, long, short)}  */
 959     @ForceInline
 960     public void putShortVolatile(Object o, long offset, short x) {
 961         theInternalUnsafe.putShortVolatile(o, offset, x);
 962     }
 963 
 964     /** Volatile version of {@link #getChar(Object, long)}  */
 965     @ForceInline
 966     public char getCharVolatile(Object o, long offset) {
 967         return theInternalUnsafe.getCharVolatile(o, offset);
 968     }
 969 
 970     /** Volatile version of {@link #putChar(Object, long, char)}  */
 971     @ForceInline
 972     public void putCharVolatile(Object o, long offset, char x) {
 973         theInternalUnsafe.putCharVolatile(o, offset, x);
 974     }
 975 
 976     /** Volatile version of {@link #getLong(Object, long)}  */
 977     @ForceInline
 978     public long getLongVolatile(Object o, long offset) {
 979         return theInternalUnsafe.getLongVolatile(o, offset);
 980     }
 981 
 982     /** Volatile version of {@link #putLong(Object, long, long)}  */
 983     @ForceInline
 984     public void putLongVolatile(Object o, long offset, long x) {
 985         theInternalUnsafe.putLongVolatile(o, offset, x);
 986     }
 987 
 988     /** Volatile version of {@link #getFloat(Object, long)}  */
 989     @ForceInline
 990     public float getFloatVolatile(Object o, long offset) {
 991         return theInternalUnsafe.getFloatVolatile(o, offset);
 992     }
 993 
 994     /** Volatile version of {@link #putFloat(Object, long, float)}  */
 995     @ForceInline
 996     public void putFloatVolatile(Object o, long offset, float x) {
 997         theInternalUnsafe.putFloatVolatile(o, offset, x);
 998     }
 999 
1000     /** Volatile version of {@link #getDouble(Object, long)}  */
1001     @ForceInline
1002     public double getDoubleVolatile(Object o, long offset) {
1003         return theInternalUnsafe.getDoubleVolatile(o, offset);
1004     }
1005 
1006     /** Volatile version of {@link #putDouble(Object, long, double)}  */
1007     @ForceInline
1008     public void putDoubleVolatile(Object o, long offset, double x) {
1009         theInternalUnsafe.putDoubleVolatile(o, offset, x);
1010     }
1011 
1012     /**
1013      * Version of {@link #putObjectVolatile(Object, long, Object)}
1014      * that does not guarantee immediate visibility of the store to
1015      * other threads. This method is generally only useful if the
1016      * underlying field is a Java volatile (or if an array cell, one
1017      * that is otherwise only accessed using volatile accesses).
1018      *
1019      * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
1020      */
1021     @ForceInline
1022     public void putOrderedObject(Object o, long offset, Object x) {
1023         theInternalUnsafe.putReferenceRelease(o, offset, x);
1024     }
1025 
1026     /** Ordered/Lazy version of {@link #putIntVolatile(Object, long, int)}  */
1027     @ForceInline
1028     public void putOrderedInt(Object o, long offset, int x) {
1029         theInternalUnsafe.putIntRelease(o, offset, x);
1030     }
1031 
1032     /** Ordered/Lazy version of {@link #putLongVolatile(Object, long, long)} */
1033     @ForceInline
1034     public void putOrderedLong(Object o, long offset, long x) {
1035         theInternalUnsafe.putLongRelease(o, offset, x);
1036     }
1037 
1038     /**
1039      * Unblocks the given thread blocked on {@code park}, or, if it is
1040      * not blocked, causes the subsequent call to {@code park} not to
1041      * block.  Note: this operation is "unsafe" solely because the
1042      * caller must somehow ensure that the thread has not been
1043      * destroyed. Nothing special is usually required to ensure this
1044      * when called from Java (in which there will ordinarily be a live
1045      * reference to the thread) but this is not nearly-automatically
1046      * so when calling from native code.
1047      *
1048      * @param thread the thread to unpark.
1049      */
1050     @ForceInline
1051     public void unpark(Object thread) {
1052         theInternalUnsafe.unpark(thread);
1053     }
1054 
1055     /**
1056      * Blocks current thread, returning when a balancing
1057      * {@code unpark} occurs, or a balancing {@code unpark} has
1058      * already occurred, or the thread is interrupted, or, if not
1059      * absolute and time is not zero, the given time nanoseconds have
1060      * elapsed, or if absolute, the given deadline in milliseconds
1061      * since Epoch has passed, or spuriously (i.e., returning for no
1062      * "reason"). Note: This operation is in the Unsafe class only
1063      * because {@code unpark} is, so it would be strange to place it
1064      * elsewhere.
1065      */
1066     @ForceInline
1067     public void park(boolean isAbsolute, long time) {
1068         theInternalUnsafe.park(isAbsolute, time);
1069     }
1070 
1071     /**
1072      * Gets the load average in the system run queue assigned
1073      * to the available processors averaged over various periods of time.
1074      * This method retrieves the given {@code nelem} samples and
1075      * assigns to the elements of the given {@code loadavg} array.
1076      * The system imposes a maximum of 3 samples, representing
1077      * averages over the last 1,  5,  and  15 minutes, respectively.
1078      *
1079      * @param loadavg an array of double of size nelems
1080      * @param nelems the number of samples to be retrieved and
1081      *        must be 1 to 3.
1082      *
1083      * @return the number of samples actually retrieved; or -1
1084      *         if the load average is unobtainable.
1085      */
1086     @ForceInline
1087     public int getLoadAverage(double[] loadavg, int nelems) {
1088         return theInternalUnsafe.getLoadAverage(loadavg, nelems);
1089     }
1090 
1091     // The following contain CAS-based Java implementations used on
1092     // platforms not supporting native instructions
1093 
1094     /**
1095      * Atomically adds the given value to the current value of a field
1096      * or array element within the given object {@code o}
1097      * at the given {@code offset}.
1098      *
1099      * @param o object/array to update the field/element in
1100      * @param offset field/element offset
1101      * @param delta the value to add
1102      * @return the previous value
1103      * @since 1.8
1104      */
1105     @ForceInline
1106     public final int getAndAddInt(Object o, long offset, int delta) {
1107         return theInternalUnsafe.getAndAddInt(o, offset, delta);
1108     }
1109 
1110     /**
1111      * Atomically adds the given value to the current value of a field
1112      * or array element within the given object {@code o}
1113      * at the given {@code offset}.
1114      *
1115      * @param o object/array to update the field/element in
1116      * @param offset field/element offset
1117      * @param delta the value to add
1118      * @return the previous value
1119      * @since 1.8
1120      */
1121     @ForceInline
1122     public final long getAndAddLong(Object o, long offset, long delta) {
1123         return theInternalUnsafe.getAndAddLong(o, offset, delta);
1124     }
1125 
1126     /**
1127      * Atomically exchanges the given value with the current value of
1128      * a field or array element within the given object {@code o}
1129      * at the given {@code offset}.
1130      *
1131      * @param o object/array to update the field/element in
1132      * @param offset field/element offset
1133      * @param newValue new value
1134      * @return the previous value
1135      * @since 1.8
1136      */
1137     @ForceInline
1138     public final int getAndSetInt(Object o, long offset, int newValue) {
1139         return theInternalUnsafe.getAndSetInt(o, offset, newValue);
1140     }
1141 
1142     /**
1143      * Atomically exchanges the given value with the current value of
1144      * a field or array element within the given object {@code o}
1145      * at the given {@code offset}.
1146      *
1147      * @param o object/array to update the field/element in
1148      * @param offset field/element offset
1149      * @param newValue new value
1150      * @return the previous value
1151      * @since 1.8
1152      */
1153     @ForceInline
1154     public final long getAndSetLong(Object o, long offset, long newValue) {
1155         return theInternalUnsafe.getAndSetLong(o, offset, newValue);
1156     }
1157 
1158     /**
1159      * Atomically exchanges the given reference value with the current
1160      * reference value of a field or array element within the given
1161      * object {@code o} at the given {@code offset}.
1162      *
1163      * @param o object/array to update the field/element in
1164      * @param offset field/element offset
1165      * @param newValue new value
1166      * @return the previous value
1167      * @since 1.8
1168      */
1169     @ForceInline
1170     public final Object getAndSetObject(Object o, long offset, Object newValue) {
1171         return theInternalUnsafe.getAndSetReference(o, offset, newValue);
1172     }
1173 
1174 
1175     /**
1176      * Ensures that loads before the fence will not be reordered with loads and
1177      * stores after the fence; a "LoadLoad plus LoadStore barrier".
1178      *
1179      * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
1180      * (an "acquire fence").
1181      *
1182      * A pure LoadLoad fence is not provided, since the addition of LoadStore
1183      * is almost always desired, and most current hardware instructions that
1184      * provide a LoadLoad barrier also provide a LoadStore barrier for free.
1185      * @since 1.8
1186      */
1187     @ForceInline
1188     public void loadFence() {
1189         theInternalUnsafe.loadFence();
1190     }
1191 
1192     /**
1193      * Ensures that loads and stores before the fence will not be reordered with
1194      * stores after the fence; a "StoreStore plus LoadStore barrier".
1195      *
1196      * Corresponds to C11 atomic_thread_fence(memory_order_release)
1197      * (a "release fence").
1198      *
1199      * A pure StoreStore fence is not provided, since the addition of LoadStore
1200      * is almost always desired, and most current hardware instructions that
1201      * provide a StoreStore barrier also provide a LoadStore barrier for free.
1202      * @since 1.8
1203      */
1204     @ForceInline
1205     public void storeFence() {
1206         theInternalUnsafe.storeFence();
1207     }
1208 
1209     /**
1210      * Ensures that loads and stores before the fence will not be reordered
1211      * with loads and stores after the fence.  Implies the effects of both
1212      * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
1213      * barrier.
1214      *
1215      * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
1216      * @since 1.8
1217      */
1218     @ForceInline
1219     public void fullFence() {
1220         theInternalUnsafe.fullFence();
1221     }
1222 
1223     /**
1224      * Invokes the given direct byte buffer's cleaner, if any.
1225      *
1226      * @param directBuffer a direct byte buffer
1227      * @throws NullPointerException if {@code directBuffer} is null
1228      * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
1229      * or is a {@link java.nio.Buffer#slice slice}, or is a
1230      * {@link java.nio.Buffer#duplicate duplicate}
1231      * @since 9
1232      */
1233     public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
1234         if (!directBuffer.isDirect())
1235             throw new IllegalArgumentException("buffer is non-direct");
1236 
1237         DirectBuffer db = (DirectBuffer)directBuffer;
1238         if (db.attachment() != null)
1239             throw new IllegalArgumentException("duplicate or slice");
1240 
1241         Cleaner cleaner = db.cleaner();
1242         if (cleaner != null) {
1243             cleaner.clean();
1244         }
1245     }
1246 }