1 /*

     2  * Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  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.security.ProtectionDomain;

    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, "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.getObject(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.putObject(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      * Tells the VM to define a class, without security checks.  By default, the

   815      * class loader and protection domain come from the caller's class.

   816      *

   817      * @deprecated Use {@link java.lang.invoke.MethodHandles.Lookup#defineClass MethodHandles.Lookup#defineClass}

   818      * to define a class to the same class loader and in the same runtime package

   819      * and {@linkplain java.security.ProtectionDomain protection domain} of a

   820      * given {@code Lookup}'s {@linkplain java.lang.invoke.MethodHandles.Lookup#lookupClass() lookup class}.

   821      *

   822      * @see java.lang.invoke.MethodHandles.Lookup#defineClass(byte[])

   823      */

   824     @Deprecated(since="9", forRemoval=true)

   825     @ForceInline

   826     public Class<?> defineClass(String name, byte[] b, int off, int len,

   827                                 ClassLoader loader,

   828                                 ProtectionDomain protectionDomain) {

   829         return theInternalUnsafe.defineClass(name, b, off, len, loader, protectionDomain);

   830     }

   831 

   832     /**

   833      * Defines a class but does not make it known to the class loader or system dictionary.

   834      * <p>

   835      * For each CP entry, the corresponding CP patch must either be null or have

   836      * the a format that matches its tag:

   837      * <ul>

   838      * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang

   839      * <li>Utf8: a string (must have suitable syntax if used as signature or name)

   840      * <li>Class: any java.lang.Class object

   841      * <li>String: any object (not just a java.lang.String)

   842      * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments

   843      * </ul>

   844      * @param hostClass context for linkage, access control, protection domain, and class loader

   845      * @param data      bytes of a class file

   846      * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data

   847      */

   848     @ForceInline

   849     public Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches) {

   850         return theInternalUnsafe.defineAnonymousClass(hostClass, data, cpPatches);

   851     }

   852 

   853     /**

   854      * Allocates an instance but does not run any constructor.

   855      * Initializes the class if it has not yet been.

   856      */

   857     @ForceInline

   858     public Object allocateInstance(Class<?> cls)

   859         throws InstantiationException {

   860         return theInternalUnsafe.allocateInstance(cls);

   861     }

   862 

   863     /** Throws the exception without telling the verifier. */

   864     @ForceInline

   865     public void throwException(Throwable ee) {

   866         theInternalUnsafe.throwException(ee);

   867     }

   868 

   869     /**

   870      * Atomically updates Java variable to {@code x} if it is currently

   871      * holding {@code expected}.

   872      *

   873      * <p>This operation has memory semantics of a {@code volatile} read

   874      * and write.  Corresponds to C11 atomic_compare_exchange_strong.

   875      *

   876      * @return {@code true} if successful

   877      */

   878     @ForceInline

   879     public final boolean compareAndSwapObject(Object o, long offset,

   880                                               Object expected,

   881                                               Object x) {

   882         return theInternalUnsafe.compareAndSetObject(o, offset, expected, x);

   883     }

   884 

   885     /**

   886      * Atomically updates Java variable to {@code x} if it is currently

   887      * holding {@code expected}.

   888      *

   889      * <p>This operation has memory semantics of a {@code volatile} read

   890      * and write.  Corresponds to C11 atomic_compare_exchange_strong.

   891      *

   892      * @return {@code true} if successful

   893      */

   894     @ForceInline

   895     public final boolean compareAndSwapInt(Object o, long offset,

   896                                            int expected,

   897                                            int x) {

   898         return theInternalUnsafe.compareAndSetInt(o, offset, expected, x);

   899     }

   900 

   901     /**

   902      * Atomically updates Java variable to {@code x} if it is currently

   903      * holding {@code expected}.

   904      *

   905      * <p>This operation has memory semantics of a {@code volatile} read

   906      * and write.  Corresponds to C11 atomic_compare_exchange_strong.

   907      *

   908      * @return {@code true} if successful

   909      */

   910     @ForceInline

   911     public final boolean compareAndSwapLong(Object o, long offset,

   912                                             long expected,

   913                                             long x) {

   914         return theInternalUnsafe.compareAndSetLong(o, offset, expected, x);

   915     }

   916 

   917     /**

   918      * Fetches a reference value from a given Java variable, with volatile

   919      * load semantics. Otherwise identical to {@link #getObject(Object, long)}

   920      */

   921     @ForceInline

   922     public Object getObjectVolatile(Object o, long offset) {

   923         return theInternalUnsafe.getObjectVolatile(o, offset);

   924     }

   925 

   926     /**

   927      * Stores a reference value into a given Java variable, with

   928      * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)}

   929      */

   930     @ForceInline

   931     public void putObjectVolatile(Object o, long offset, Object x) {

   932         theInternalUnsafe.putObjectVolatile(o, offset, x);

   933     }

   934 

   935     /** Volatile version of {@link #getInt(Object, long)}  */

   936     @ForceInline

   937     public int getIntVolatile(Object o, long offset) {

   938         return theInternalUnsafe.getIntVolatile(o, offset);

   939     }

   940 

   941     /** Volatile version of {@link #putInt(Object, long, int)}  */

   942     @ForceInline

   943     public void putIntVolatile(Object o, long offset, int x) {

   944         theInternalUnsafe.putIntVolatile(o, offset, x);

   945     }

   946 

   947     /** Volatile version of {@link #getBoolean(Object, long)}  */

   948     @ForceInline

   949     public boolean getBooleanVolatile(Object o, long offset) {

   950         return theInternalUnsafe.getBooleanVolatile(o, offset);

   951     }

   952 

   953     /** Volatile version of {@link #putBoolean(Object, long, boolean)}  */

   954     @ForceInline

   955     public void putBooleanVolatile(Object o, long offset, boolean x) {

   956         theInternalUnsafe.putBooleanVolatile(o, offset, x);

   957     }

   958 

   959     /** Volatile version of {@link #getByte(Object, long)}  */

   960     @ForceInline

   961     public byte getByteVolatile(Object o, long offset) {

   962         return theInternalUnsafe.getByteVolatile(o, offset);

   963     }

   964 

   965     /** Volatile version of {@link #putByte(Object, long, byte)}  */

   966     @ForceInline

   967     public void putByteVolatile(Object o, long offset, byte x) {

   968         theInternalUnsafe.putByteVolatile(o, offset, x);

   969     }

   970 

   971     /** Volatile version of {@link #getShort(Object, long)}  */

   972     @ForceInline

   973     public short getShortVolatile(Object o, long offset) {

   974         return theInternalUnsafe.getShortVolatile(o, offset);

   975     }

   976 

   977     /** Volatile version of {@link #putShort(Object, long, short)}  */

   978     @ForceInline

   979     public void putShortVolatile(Object o, long offset, short x) {

   980         theInternalUnsafe.putShortVolatile(o, offset, x);

   981     }

   982 

   983     /** Volatile version of {@link #getChar(Object, long)}  */

   984     @ForceInline

   985     public char getCharVolatile(Object o, long offset) {

   986         return theInternalUnsafe.getCharVolatile(o, offset);

   987     }

   988 

   989     /** Volatile version of {@link #putChar(Object, long, char)}  */

   990     @ForceInline

   991     public void putCharVolatile(Object o, long offset, char x) {

   992         theInternalUnsafe.putCharVolatile(o, offset, x);

   993     }

   994 

   995     /** Volatile version of {@link #getLong(Object, long)}  */

   996     @ForceInline

   997     public long getLongVolatile(Object o, long offset) {

   998         return theInternalUnsafe.getLongVolatile(o, offset);

   999     }

  1000 

  1001     /** Volatile version of {@link #putLong(Object, long, long)}  */

  1002     @ForceInline

  1003     public void putLongVolatile(Object o, long offset, long x) {

  1004         theInternalUnsafe.putLongVolatile(o, offset, x);

  1005     }

  1006 

  1007     /** Volatile version of {@link #getFloat(Object, long)}  */

  1008     @ForceInline

  1009     public float getFloatVolatile(Object o, long offset) {

  1010         return theInternalUnsafe.getFloatVolatile(o, offset);

  1011     }

  1012 

  1013     /** Volatile version of {@link #putFloat(Object, long, float)}  */

  1014     @ForceInline

  1015     public void putFloatVolatile(Object o, long offset, float x) {

  1016         theInternalUnsafe.putFloatVolatile(o, offset, x);

  1017     }

  1018 

  1019     /** Volatile version of {@link #getDouble(Object, long)}  */

  1020     @ForceInline

  1021     public double getDoubleVolatile(Object o, long offset) {

  1022         return theInternalUnsafe.getDoubleVolatile(o, offset);

  1023     }

  1024 

  1025     /** Volatile version of {@link #putDouble(Object, long, double)}  */

  1026     @ForceInline

  1027     public void putDoubleVolatile(Object o, long offset, double x) {

  1028         theInternalUnsafe.putDoubleVolatile(o, offset, x);

  1029     }

  1030 

  1031     /**

  1032      * Version of {@link #putObjectVolatile(Object, long, Object)}

  1033      * that does not guarantee immediate visibility of the store to

  1034      * other threads. This method is generally only useful if the

  1035      * underlying field is a Java volatile (or if an array cell, one

  1036      * that is otherwise only accessed using volatile accesses).

  1037      *

  1038      * Corresponds to C11 atomic_store_explicit(..., memory_order_release).

  1039      */

  1040     @ForceInline

  1041     public void putOrderedObject(Object o, long offset, Object x) {

  1042         theInternalUnsafe.putObjectRelease(o, offset, x);

  1043     }

  1044 

  1045     /** Ordered/Lazy version of {@link #putIntVolatile(Object, long, int)}  */

  1046     @ForceInline

  1047     public void putOrderedInt(Object o, long offset, int x) {

  1048         theInternalUnsafe.putIntRelease(o, offset, x);

  1049     }

  1050 

  1051     /** Ordered/Lazy version of {@link #putLongVolatile(Object, long, long)} */

  1052     @ForceInline

  1053     public void putOrderedLong(Object o, long offset, long x) {

  1054         theInternalUnsafe.putLongRelease(o, offset, x);

  1055     }

  1056 

  1057     /**

  1058      * Unblocks the given thread blocked on {@code park}, or, if it is

  1059      * not blocked, causes the subsequent call to {@code park} not to

  1060      * block.  Note: this operation is "unsafe" solely because the

  1061      * caller must somehow ensure that the thread has not been

  1062      * destroyed. Nothing special is usually required to ensure this

  1063      * when called from Java (in which there will ordinarily be a live

  1064      * reference to the thread) but this is not nearly-automatically

  1065      * so when calling from native code.

  1066      *

  1067      * @param thread the thread to unpark.

  1068      */

  1069     @ForceInline

  1070     public void unpark(Object thread) {

  1071         theInternalUnsafe.unpark(thread);

  1072     }

  1073 

  1074     /**

  1075      * Blocks current thread, returning when a balancing

  1076      * {@code unpark} occurs, or a balancing {@code unpark} has

  1077      * already occurred, or the thread is interrupted, or, if not

  1078      * absolute and time is not zero, the given time nanoseconds have

  1079      * elapsed, or if absolute, the given deadline in milliseconds

  1080      * since Epoch has passed, or spuriously (i.e., returning for no

  1081      * "reason"). Note: This operation is in the Unsafe class only

  1082      * because {@code unpark} is, so it would be strange to place it

  1083      * elsewhere.

  1084      */

  1085     @ForceInline

  1086     public void park(boolean isAbsolute, long time) {

  1087         theInternalUnsafe.park(isAbsolute, time);

  1088     }

  1089 

  1090     /**

  1091      * Gets the load average in the system run queue assigned

  1092      * to the available processors averaged over various periods of time.

  1093      * This method retrieves the given {@code nelem} samples and

  1094      * assigns to the elements of the given {@code loadavg} array.

  1095      * The system imposes a maximum of 3 samples, representing

  1096      * averages over the last 1,  5,  and  15 minutes, respectively.

  1097      *

  1098      * @param loadavg an array of double of size nelems

  1099      * @param nelems the number of samples to be retrieved and

  1100      *        must be 1 to 3.

  1101      *

  1102      * @return the number of samples actually retrieved; or -1

  1103      *         if the load average is unobtainable.

  1104      */

  1105     @ForceInline

  1106     public int getLoadAverage(double[] loadavg, int nelems) {

  1107         return theInternalUnsafe.getLoadAverage(loadavg, nelems);

  1108     }

  1109 

  1110     // The following contain CAS-based Java implementations used on

  1111     // platforms not supporting native instructions

  1112 

  1113     /**

  1114      * Atomically adds the given value to the current value of a field

  1115      * or array element within the given object {@code o}

  1116      * at the given {@code offset}.

  1117      *

  1118      * @param o object/array to update the field/element in

  1119      * @param offset field/element offset

  1120      * @param delta the value to add

  1121      * @return the previous value

  1122      * @since 1.8

  1123      */

  1124     @ForceInline

  1125     public final int getAndAddInt(Object o, long offset, int delta) {

  1126         return theInternalUnsafe.getAndAddInt(o, offset, delta);

  1127     }

  1128 

  1129     /**

  1130      * Atomically adds the given value to the current value of a field

  1131      * or array element within the given object {@code o}

  1132      * at the given {@code offset}.

  1133      *

  1134      * @param o object/array to update the field/element in