1 /*
2 * Copyright (c) 2000, 2025, 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 jdk.internal.misc;
27
28 import jdk.internal.ref.Cleaner;
29 import jdk.internal.vm.annotation.ForceInline;
30 import jdk.internal.vm.annotation.IntrinsicCandidate;
31 import sun.nio.ch.DirectBuffer;
32
33 import java.lang.reflect.Field;
34 import java.security.ProtectionDomain;
35
36 import static jdk.internal.misc.UnsafeConstants.*;
37
38 /**
39 * A collection of methods for performing low-level, unsafe operations.
40 * Although the class and all methods are public, use of this class is
41 * limited because only trusted code can obtain instances of it.
42 *
43 * <em>Note:</em> It is the responsibility of the caller to make sure
44 * arguments are checked before methods of this class are
45 * called. While some rudimentary checks are performed on the input,
46 * the checks are best effort and when performance is an overriding
47 * priority, as when methods of this class are optimized by the
48 * runtime compiler, some or all checks (if any) may be elided. Hence,
49 * the caller must not rely on the checks and corresponding
50 * exceptions!
51 *
52 * @author John R. Rose
53 * @see #getUnsafe
54 */
55
56 public final class Unsafe {
57
58 private static native void registerNatives();
59 static {
60 runtimeSetup();
61 }
62
63 // Called from JVM when loading an AOT cache
64 private static void runtimeSetup() {
65 registerNatives();
66 }
67
68 private Unsafe() {}
69
70 private static final Unsafe theUnsafe = new Unsafe();
71
72 /**
73 * Provides the caller with the capability of performing unsafe
74 * operations.
75 *
76 * <p>The returned {@code Unsafe} object should be carefully guarded
77 * by the caller, since it can be used to read and write data at arbitrary
78 * memory addresses. It must never be passed to untrusted code.
79 *
80 * <p>Most methods in this class are very low-level, and correspond to a
81 * small number of hardware instructions (on typical machines). Compilers
82 * are encouraged to optimize these methods accordingly.
83 *
84 * <p>Here is a suggested idiom for using unsafe operations:
85 *
86 * <pre> {@code
87 * class MyTrustedClass {
88 * private static final Unsafe unsafe = Unsafe.getUnsafe();
89 * ...
90 * private long myCountAddress = ...;
91 * public int getCount() { return unsafe.getByte(myCountAddress); }
92 * }}</pre>
93 *
94 * (It may assist compilers to make the local variable {@code final}.)
95 */
96 public static Unsafe getUnsafe() {
97 return theUnsafe;
98 }
99
100 //--- peek and poke operations
101 // (compilers should optimize these to memory ops)
102
103 // These work on object fields in the Java heap.
104 // They will not work on elements of packed arrays.
105
106 /**
107 * Fetches a value from a given Java variable.
108 * More specifically, fetches a field or array element within the given
109 * object {@code o} at the given offset, or (if {@code o} is null)
110 * from the memory address whose numerical value is the given offset.
111 * <p>
112 * The results are undefined unless one of the following cases is true:
113 * <ul>
114 * <li>The offset was obtained from {@link #objectFieldOffset} on
115 * the {@link java.lang.reflect.Field} of some Java field and the object
116 * referred to by {@code o} is of a class compatible with that
117 * field's class.
118 *
119 * <li>The offset and object reference {@code o} (either null or
120 * non-null) were both obtained via {@link #staticFieldOffset}
121 * and {@link #staticFieldBase} (respectively) from the
122 * reflective {@link Field} representation of some Java field.
123 *
124 * <li>The object referred to by {@code o} is an array, and the offset
125 * is an integer of the form {@code B+N*S}, where {@code N} is
126 * a valid index into the array, and {@code B} and {@code S} are
127 * the values obtained by {@link #arrayBaseOffset} and {@link
128 * #arrayIndexScale} (respectively) from the array's class. The value
129 * referred to is the {@code N}<em>th</em> element of the array.
130 *
131 * </ul>
132 * <p>
133 * If one of the above cases is true, the call references a specific Java
134 * variable (field or array element). However, the results are undefined
135 * if that variable is not in fact of the type returned by this method.
136 * <p>
137 * This method refers to a variable by means of two parameters, and so
138 * it provides (in effect) a <em>double-register</em> addressing mode
139 * for Java variables. When the object reference is null, this method
140 * uses its offset as an absolute address. This is similar in operation
141 * to methods such as {@link #getInt(long)}, which provide (in effect) a
142 * <em>single-register</em> addressing mode for non-Java variables.
143 * However, because Java variables may have a different layout in memory
144 * from non-Java variables, programmers should not assume that these
145 * two addressing modes are ever equivalent. Also, programmers should
146 * remember that offsets from the double-register addressing mode cannot
147 * be portably confused with longs used in the single-register addressing
148 * mode.
149 *
150 * @param o Java heap object in which the variable resides, if any, else
151 * null
152 * @param offset indication of where the variable resides in a Java heap
153 * object, if any, else a memory address locating the variable
154 * statically
155 * @return the value fetched from the indicated Java variable
156 * @throws RuntimeException No defined exceptions are thrown, not even
157 * {@link NullPointerException}
158 */
159 @IntrinsicCandidate
160 public native int getInt(Object o, long offset);
161
162 /**
163 * Stores a value into a given Java variable.
164 * <p>
165 * The first two parameters are interpreted exactly as with
166 * {@link #getInt(Object, long)} to refer to a specific
167 * Java variable (field or array element). The given value
168 * is stored into that variable.
169 * <p>
170 * The variable must be of the same type as the method
171 * parameter {@code x}.
172 *
173 * @param o Java heap object in which the variable resides, if any, else
174 * null
175 * @param offset indication of where the variable resides in a Java heap
176 * object, if any, else a memory address locating the variable
177 * statically
178 * @param x the value to store into the indicated Java variable
179 * @throws RuntimeException No defined exceptions are thrown, not even
180 * {@link NullPointerException}
181 */
182 @IntrinsicCandidate
183 public native void putInt(Object o, long offset, int x);
184
185 /**
186 * Fetches a reference value from a given Java variable.
187 * @see #getInt(Object, long)
188 */
189 @IntrinsicCandidate
190 public native Object getReference(Object o, long offset);
191
192 /**
193 * Stores a reference value into a given Java variable.
194 * <p>
195 * Unless the reference {@code x} being stored is either null
196 * or matches the field type, the results are undefined.
197 * If the reference {@code o} is non-null, card marks or
198 * other store barriers for that object (if the VM requires them)
199 * are updated.
200 * @see #putInt(Object, long, int)
201 */
202 @IntrinsicCandidate
203 public native void putReference(Object o, long offset, Object x);
204
205 /** @see #getInt(Object, long) */
206 @IntrinsicCandidate
207 public native boolean getBoolean(Object o, long offset);
208
209 /** @see #putInt(Object, long, int) */
210 @IntrinsicCandidate
211 public native void putBoolean(Object o, long offset, boolean x);
212
213 /** @see #getInt(Object, long) */
214 @IntrinsicCandidate
215 public native byte getByte(Object o, long offset);
216
217 /** @see #putInt(Object, long, int) */
218 @IntrinsicCandidate
219 public native void putByte(Object o, long offset, byte x);
220
221 /** @see #getInt(Object, long) */
222 @IntrinsicCandidate
223 public native short getShort(Object o, long offset);
224
225 /** @see #putInt(Object, long, int) */
226 @IntrinsicCandidate
227 public native void putShort(Object o, long offset, short x);
228
229 /** @see #getInt(Object, long) */
230 @IntrinsicCandidate
231 public native char getChar(Object o, long offset);
232
233 /** @see #putInt(Object, long, int) */
234 @IntrinsicCandidate
235 public native void putChar(Object o, long offset, char x);
236
237 /** @see #getInt(Object, long) */
238 @IntrinsicCandidate
239 public native long getLong(Object o, long offset);
240
241 /** @see #putInt(Object, long, int) */
242 @IntrinsicCandidate
243 public native void putLong(Object o, long offset, long x);
244
245 /** @see #getInt(Object, long) */
246 @IntrinsicCandidate
247 public native float getFloat(Object o, long offset);
248
249 /** @see #putInt(Object, long, int) */
250 @IntrinsicCandidate
251 public native void putFloat(Object o, long offset, float x);
252
253 /** @see #getInt(Object, long) */
254 @IntrinsicCandidate
255 public native double getDouble(Object o, long offset);
256
257 /** @see #putInt(Object, long, int) */
258 @IntrinsicCandidate
259 public native void putDouble(Object o, long offset, double x);
260
261 /**
262 * Fetches a native pointer from a given memory address. If the address is
263 * zero, or does not point into a block obtained from {@link
264 * #allocateMemory}, the results are undefined.
265 *
266 * <p>If the native pointer is less than 64 bits wide, it is extended as
267 * an unsigned number to a Java long. The pointer may be indexed by any
268 * given byte offset, simply by adding that offset (as a simple integer) to
269 * the long representing the pointer. The number of bytes actually read
270 * from the target address may be determined by consulting {@link
271 * #addressSize}.
272 *
273 * @see #allocateMemory
274 * @see #getInt(Object, long)
275 */
276 @ForceInline
277 public long getAddress(Object o, long offset) {
278 if (ADDRESS_SIZE == 4) {
279 return Integer.toUnsignedLong(getInt(o, offset));
280 } else {
281 return getLong(o, offset);
282 }
283 }
284
285 /**
286 * Stores a native pointer into a given memory address. If the address is
287 * zero, or does not point into a block obtained from {@link
288 * #allocateMemory}, the results are undefined.
289 *
290 * <p>The number of bytes actually written at the target address may be
291 * determined by consulting {@link #addressSize}.
292 *
293 * @see #allocateMemory
294 * @see #putInt(Object, long, int)
295 */
296 @ForceInline
297 public void putAddress(Object o, long offset, long x) {
298 if (ADDRESS_SIZE == 4) {
299 putInt(o, offset, (int)x);
300 } else {
301 putLong(o, offset, x);
302 }
303 }
304
305 // These read VM internal data.
306
307 /**
308 * Fetches an uncompressed reference value from a given native variable
309 * ignoring the VM's compressed references mode.
310 *
311 * @param address a memory address locating the variable
312 * @return the value fetched from the indicated native variable
313 */
314 public native Object getUncompressedObject(long address);
315
316 // These work on values in the C heap.
317
318 /**
319 * Fetches a value from a given memory address. If the address is zero, or
320 * does not point into a block obtained from {@link #allocateMemory}, the
321 * results are undefined.
322 *
323 * @see #allocateMemory
324 */
325 @ForceInline
326 public byte getByte(long address) {
327 return getByte(null, address);
328 }
329
330 /**
331 * Stores a value into a given memory address. If the address is zero, or
332 * does not point into a block obtained from {@link #allocateMemory}, the
333 * results are undefined.
334 *
335 * @see #getByte(long)
336 */
337 @ForceInline
338 public void putByte(long address, byte x) {
339 putByte(null, address, x);
340 }
341
342 /** @see #getByte(long) */
343 @ForceInline
344 public short getShort(long address) {
345 return getShort(null, address);
346 }
347
348 /** @see #putByte(long, byte) */
349 @ForceInline
350 public void putShort(long address, short x) {
351 putShort(null, address, x);
352 }
353
354 /** @see #getByte(long) */
355 @ForceInline
356 public char getChar(long address) {
357 return getChar(null, address);
358 }
359
360 /** @see #putByte(long, byte) */
361 @ForceInline
362 public void putChar(long address, char x) {
363 putChar(null, address, x);
364 }
365
366 /** @see #getByte(long) */
367 @ForceInline
368 public int getInt(long address) {
369 return getInt(null, address);
370 }
371
372 /** @see #putByte(long, byte) */
373 @ForceInline
374 public void putInt(long address, int x) {
375 putInt(null, address, x);
376 }
377
378 /** @see #getByte(long) */
379 @ForceInline
380 public long getLong(long address) {
381 return getLong(null, address);
382 }
383
384 /** @see #putByte(long, byte) */
385 @ForceInline
386 public void putLong(long address, long x) {
387 putLong(null, address, x);
388 }
389
390 /** @see #getByte(long) */
391 @ForceInline
392 public float getFloat(long address) {
393 return getFloat(null, address);
394 }
395
396 /** @see #putByte(long, byte) */
397 @ForceInline
398 public void putFloat(long address, float x) {
399 putFloat(null, address, x);
400 }
401
402 /** @see #getByte(long) */
403 @ForceInline
404 public double getDouble(long address) {
405 return getDouble(null, address);
406 }
407
408 /** @see #putByte(long, byte) */
409 @ForceInline
410 public void putDouble(long address, double x) {
411 putDouble(null, address, x);
412 }
413
414 /** @see #getAddress(Object, long) */
415 @ForceInline
416 public long getAddress(long address) {
417 return getAddress(null, address);
418 }
419
420 /** @see #putAddress(Object, long, long) */
421 @ForceInline
422 public void putAddress(long address, long x) {
423 putAddress(null, address, x);
424 }
425
426
427
428 //--- helper methods for validating various types of objects/values
429
430 /**
431 * Create an exception reflecting that some of the input was invalid
432 *
433 * <em>Note:</em> It is the responsibility of the caller to make
434 * sure arguments are checked before the methods are called. While
435 * some rudimentary checks are performed on the input, the checks
436 * are best effort and when performance is an overriding priority,
437 * as when methods of this class are optimized by the runtime
438 * compiler, some or all checks (if any) may be elided. Hence, the
439 * caller must not rely on the checks and corresponding
440 * exceptions!
441 *
442 * @return an exception object
443 */
444 private RuntimeException invalidInput() {
445 return new IllegalArgumentException();
446 }
447
448 /**
449 * Check if a value is 32-bit clean (32 MSB are all zero)
450 *
451 * @param value the 64-bit value to check
452 *
453 * @return true if the value is 32-bit clean
454 */
455 private boolean is32BitClean(long value) {
456 return value >>> 32 == 0;
457 }
458
459 /**
460 * Check the validity of a size (the equivalent of a size_t)
461 *
462 * @throws RuntimeException if the size is invalid
463 * (<em>Note:</em> after optimization, invalid inputs may
464 * go undetected, which will lead to unpredictable
465 * behavior)
466 */
467 private void checkSize(long size) {
468 if (ADDRESS_SIZE == 4) {
469 // Note: this will also check for negative sizes
470 if (!is32BitClean(size)) {
471 throw invalidInput();
472 }
473 } else if (size < 0) {
474 throw invalidInput();
475 }
476 }
477
478 /**
479 * Check the validity of a native address (the equivalent of void*)
480 *
481 * @throws RuntimeException if the address is invalid
482 * (<em>Note:</em> after optimization, invalid inputs may
483 * go undetected, which will lead to unpredictable
484 * behavior)
485 */
486 private void checkNativeAddress(long address) {
487 if (ADDRESS_SIZE == 4) {
488 // Accept both zero and sign extended pointers. A valid
489 // pointer will, after the +1 below, either have produced
490 // the value 0x0 or 0x1. Masking off the low bit allows
491 // for testing against 0.
492 if ((((address >> 32) + 1) & ~1) != 0) {
493 throw invalidInput();
494 }
495 }
496 }
497
498 /**
499 * Check the validity of an offset, relative to a base object
500 *
501 * @param o the base object
502 * @param offset the offset to check
503 *
504 * @throws RuntimeException if the size is invalid
505 * (<em>Note:</em> after optimization, invalid inputs may
506 * go undetected, which will lead to unpredictable
507 * behavior)
508 */
509 private void checkOffset(Object o, long offset) {
510 if (ADDRESS_SIZE == 4) {
511 // Note: this will also check for negative offsets
512 if (!is32BitClean(offset)) {
513 throw invalidInput();
514 }
515 } else if (offset < 0) {
516 throw invalidInput();
517 }
518 }
519
520 /**
521 * Check the validity of a double-register pointer
522 *
523 * Note: This code deliberately does *not* check for NPE for (at
524 * least) three reasons:
525 *
526 * 1) NPE is not just NULL/0 - there is a range of values all
527 * resulting in an NPE, which is not trivial to check for
528 *
529 * 2) It is the responsibility of the callers of Unsafe methods
530 * to verify the input, so throwing an exception here is not really
531 * useful - passing in a NULL pointer is a critical error and the
532 * must not expect an exception to be thrown anyway.
533 *
534 * 3) the actual operations will detect NULL pointers anyway by
535 * means of traps and signals (like SIGSEGV).
536 *
537 * @param o Java heap object, or null
538 * @param offset indication of where the variable resides in a Java heap
539 * object, if any, else a memory address locating the variable
540 * statically
541 *
542 * @throws RuntimeException if the pointer is invalid
543 * (<em>Note:</em> after optimization, invalid inputs may
544 * go undetected, which will lead to unpredictable
545 * behavior)
546 */
547 private void checkPointer(Object o, long offset) {
548 if (o == null) {
549 checkNativeAddress(offset);
550 } else {
551 checkOffset(o, offset);
552 }
553 }
554
555 /**
556 * Check if a type is a primitive array type
557 *
558 * @param c the type to check
559 *
560 * @return true if the type is a primitive array type
561 */
562 private void checkPrimitiveArray(Class<?> c) {
563 Class<?> componentType = c.getComponentType();
564 if (componentType == null || !componentType.isPrimitive()) {
565 throw invalidInput();
566 }
567 }
568
569 /**
570 * Check that a pointer is a valid primitive array type pointer
571 *
572 * Note: pointers off-heap are considered to be primitive arrays
573 *
574 * @throws RuntimeException if the pointer is invalid
575 * (<em>Note:</em> after optimization, invalid inputs may
576 * go undetected, which will lead to unpredictable
577 * behavior)
578 */
579 private void checkPrimitivePointer(Object o, long offset) {
580 checkPointer(o, offset);
581
582 if (o != null) {
583 // If on heap, it must be a primitive array
584 checkPrimitiveArray(o.getClass());
585 }
586 }
587
588
589 //--- wrappers for malloc, realloc, free:
590
591 /**
592 * Round up allocation size to a multiple of HeapWordSize.
593 */
594 private long alignToHeapWordSize(long bytes) {
595 if (bytes >= 0) {
596 return (bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1);
597 } else {
598 throw invalidInput();
599 }
600 }
601
602 /**
603 * Allocates a new block of native memory, of the given size in bytes. The
604 * contents of the memory are uninitialized; they will generally be
605 * garbage. The resulting native pointer will be zero if and only if the
606 * requested size is zero. The resulting native pointer will be aligned for
607 * all value types. Dispose of this memory by calling {@link #freeMemory}
608 * or resize it with {@link #reallocateMemory}.
609 *
610 * <em>Note:</em> It is the responsibility of the caller to make
611 * sure arguments are checked before the methods are called. While
612 * some rudimentary checks are performed on the input, the checks
613 * are best effort and when performance is an overriding priority,
614 * as when methods of this class are optimized by the runtime
615 * compiler, some or all checks (if any) may be elided. Hence, the
616 * caller must not rely on the checks and corresponding
617 * exceptions!
618 *
619 * @throws RuntimeException if the size is negative or too large
620 * for the native size_t type
621 *
622 * @throws OutOfMemoryError if the allocation is refused by the system
623 *
624 * @see #getByte(long)
625 * @see #putByte(long, byte)
626 */
627 public long allocateMemory(long bytes) {
628 bytes = alignToHeapWordSize(bytes);
629
630 allocateMemoryChecks(bytes);
631
632 if (bytes == 0) {
633 return 0;
634 }
635
636 long p = allocateMemory0(bytes);
637 if (p == 0) {
638 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
639 }
640
641 return p;
642 }
643
644 /**
645 * Validate the arguments to allocateMemory
646 *
647 * @throws RuntimeException if the arguments are invalid
648 * (<em>Note:</em> after optimization, invalid inputs may
649 * go undetected, which will lead to unpredictable
650 * behavior)
651 */
652 private void allocateMemoryChecks(long bytes) {
653 checkSize(bytes);
654 }
655
656 /**
657 * Resizes a new block of native memory, to the given size in bytes. The
658 * contents of the new block past the size of the old block are
659 * uninitialized; they will generally be garbage. The resulting native
660 * pointer will be zero if and only if the requested size is zero. The
661 * resulting native pointer will be aligned for all value types. Dispose
662 * of this memory by calling {@link #freeMemory}, or resize it with {@link
663 * #reallocateMemory}. The address passed to this method may be null, in
664 * which case an allocation will be performed.
665 *
666 * <em>Note:</em> It is the responsibility of the caller to make
667 * sure arguments are checked before the methods are called. While
668 * some rudimentary checks are performed on the input, the checks
669 * are best effort and when performance is an overriding priority,
670 * as when methods of this class are optimized by the runtime
671 * compiler, some or all checks (if any) may be elided. Hence, the
672 * caller must not rely on the checks and corresponding
673 * exceptions!
674 *
675 * @throws RuntimeException if the size is negative or too large
676 * for the native size_t type
677 *
678 * @throws OutOfMemoryError if the allocation is refused by the system
679 *
680 * @see #allocateMemory
681 */
682 public long reallocateMemory(long address, long bytes) {
683 bytes = alignToHeapWordSize(bytes);
684
685 reallocateMemoryChecks(address, bytes);
686
687 if (bytes == 0) {
688 freeMemory(address);
689 return 0;
690 }
691
692 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
693 if (p == 0) {
694 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
695 }
696
697 return p;
698 }
699
700 /**
701 * Validate the arguments to reallocateMemory
702 *
703 * @throws RuntimeException if the arguments are invalid
704 * (<em>Note:</em> after optimization, invalid inputs may
705 * go undetected, which will lead to unpredictable
706 * behavior)
707 */
708 private void reallocateMemoryChecks(long address, long bytes) {
709 checkPointer(null, address);
710 checkSize(bytes);
711 }
712
713 /**
714 * Sets all bytes in a given block of memory to a fixed value
715 * (usually zero).
716 *
717 * <p>This method determines a block's base address by means of two parameters,
718 * and so it provides (in effect) a <em>double-register</em> addressing mode,
719 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
720 * the offset supplies an absolute base address.
721 *
722 * <p>The stores are in coherent (atomic) units of a size determined
723 * by the address and length parameters. If the effective address and
724 * length are all even modulo 8, the stores take place in 'long' units.
725 * If the effective address and length are (resp.) even modulo 4 or 2,
726 * the stores take place in units of 'int' or 'short'.
727 *
728 * <em>Note:</em> It is the responsibility of the caller to make
729 * sure arguments are checked before the methods are called. While
730 * some rudimentary checks are performed on the input, the checks
731 * are best effort and when performance is an overriding priority,
732 * as when methods of this class are optimized by the runtime
733 * compiler, some or all checks (if any) may be elided. Hence, the
734 * caller must not rely on the checks and corresponding
735 * exceptions!
736 *
737 * @throws RuntimeException if any of the arguments is invalid
738 *
739 * @since 1.7
740 */
741 public void setMemory(Object o, long offset, long bytes, byte value) {
742 setMemoryChecks(o, offset, bytes, value);
743
744 if (bytes == 0) {
745 return;
746 }
747
748 setMemory0(o, offset, bytes, value);
749 }
750
751 /**
752 * Sets all bytes in a given block of memory to a fixed value
753 * (usually zero). This provides a <em>single-register</em> addressing mode,
754 * as discussed in {@link #getInt(Object,long)}.
755 *
756 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
757 */
758 public void setMemory(long address, long bytes, byte value) {
759 setMemory(null, address, bytes, value);
760 }
761
762 /**
763 * Validate the arguments to setMemory
764 *
765 * @throws RuntimeException if the arguments are invalid
766 * (<em>Note:</em> after optimization, invalid inputs may
767 * go undetected, which will lead to unpredictable
768 * behavior)
769 */
770 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
771 checkPrimitivePointer(o, offset);
772 checkSize(bytes);
773 }
774
775 /**
776 * Sets all bytes in a given block of memory to a copy of another
777 * block.
778 *
779 * <p>This method determines each block's base address by means of two parameters,
780 * and so it provides (in effect) a <em>double-register</em> addressing mode,
781 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
782 * the offset supplies an absolute base address.
783 *
784 * <p>The transfers are in coherent (atomic) units of a size determined
785 * by the address and length parameters. If the effective addresses and
786 * length are all even modulo 8, the transfer takes place in 'long' units.
787 * If the effective addresses and length are (resp.) even modulo 4 or 2,
788 * the transfer takes place in units of 'int' or 'short'.
789 *
790 * <em>Note:</em> It is the responsibility of the caller to make
791 * sure arguments are checked before the methods are called. While
792 * some rudimentary checks are performed on the input, the checks
793 * are best effort and when performance is an overriding priority,
794 * as when methods of this class are optimized by the runtime
795 * compiler, some or all checks (if any) may be elided. Hence, the
796 * caller must not rely on the checks and corresponding
797 * exceptions!
798 *
799 * @throws RuntimeException if any of the arguments is invalid
800 *
801 * @since 1.7
802 */
803 public void copyMemory(Object srcBase, long srcOffset,
804 Object destBase, long destOffset,
805 long bytes) {
806 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
807
808 if (bytes == 0) {
809 return;
810 }
811
812 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
813 }
814
815 /**
816 * Sets all bytes in a given block of memory to a copy of another
817 * block. This provides a <em>single-register</em> addressing mode,
818 * as discussed in {@link #getInt(Object,long)}.
819 *
820 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
821 */
822 public void copyMemory(long srcAddress, long destAddress, long bytes) {
823 copyMemory(null, srcAddress, null, destAddress, bytes);
824 }
825
826 /**
827 * Validate the arguments to copyMemory
828 *
829 * @throws RuntimeException if any of the arguments is invalid
830 * (<em>Note:</em> after optimization, invalid inputs may
831 * go undetected, which will lead to unpredictable
832 * behavior)
833 */
834 private void copyMemoryChecks(Object srcBase, long srcOffset,
835 Object destBase, long destOffset,
836 long bytes) {
837 checkSize(bytes);
838 checkPrimitivePointer(srcBase, srcOffset);
839 checkPrimitivePointer(destBase, destOffset);
840 }
841
842 /**
843 * Copies all elements from one block of memory to another block,
844 * *unconditionally* byte swapping the elements on the fly.
845 *
846 * <p>This method determines each block's base address by means of two parameters,
847 * and so it provides (in effect) a <em>double-register</em> addressing mode,
848 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
849 * the offset supplies an absolute base address.
850 *
851 * <em>Note:</em> It is the responsibility of the caller to make
852 * sure arguments are checked before the methods are called. While
853 * some rudimentary checks are performed on the input, the checks
854 * are best effort and when performance is an overriding priority,
855 * as when methods of this class are optimized by the runtime
856 * compiler, some or all checks (if any) may be elided. Hence, the
857 * caller must not rely on the checks and corresponding
858 * exceptions!
859 *
860 * @throws RuntimeException if any of the arguments is invalid
861 *
862 * @since 9
863 */
864 public void copySwapMemory(Object srcBase, long srcOffset,
865 Object destBase, long destOffset,
866 long bytes, long elemSize) {
867 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
868
869 if (bytes == 0) {
870 return;
871 }
872
873 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
874 }
875
876 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
877 Object destBase, long destOffset,
878 long bytes, long elemSize) {
879 checkSize(bytes);
880
881 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
882 throw invalidInput();
883 }
884 if (bytes % elemSize != 0) {
885 throw invalidInput();
886 }
887
888 checkPrimitivePointer(srcBase, srcOffset);
889 checkPrimitivePointer(destBase, destOffset);
890 }
891
892 /**
893 * Copies all elements from one block of memory to another block, byte swapping the
894 * elements on the fly.
895 *
896 * This provides a <em>single-register</em> addressing mode, as
897 * discussed in {@link #getInt(Object,long)}.
898 *
899 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
900 */
901 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
902 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
903 }
904
905 /**
906 * Disposes of a block of native memory, as obtained from {@link
907 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
908 * this method may be null, in which case no action is taken.
909 *
910 * <em>Note:</em> It is the responsibility of the caller to make
911 * sure arguments are checked before the methods are called. While
912 * some rudimentary checks are performed on the input, the checks
913 * are best effort and when performance is an overriding priority,
914 * as when methods of this class are optimized by the runtime
915 * compiler, some or all checks (if any) may be elided. Hence, the
916 * caller must not rely on the checks and corresponding
917 * exceptions!
918 *
919 * @throws RuntimeException if any of the arguments is invalid
920 *
921 * @see #allocateMemory
922 */
923 public void freeMemory(long address) {
924 freeMemoryChecks(address);
925
926 if (address == 0) {
927 return;
928 }
929
930 freeMemory0(address);
931 }
932
933 /**
934 * Validate the arguments to freeMemory
935 *
936 * @throws RuntimeException if the arguments are invalid
937 * (<em>Note:</em> after optimization, invalid inputs may
938 * go undetected, which will lead to unpredictable
939 * behavior)
940 */
941 private void freeMemoryChecks(long address) {
942 checkPointer(null, address);
943 }
944
945 /**
946 * Ensure writeback of a specified virtual memory address range
947 * from cache to physical memory. All bytes in the address range
948 * are guaranteed to have been written back to physical memory on
949 * return from this call i.e. subsequently executed store
950 * instructions are guaranteed not to be visible before the
951 * writeback is completed.
952 *
953 * @param address
954 * the lowest byte address that must be guaranteed written
955 * back to memory. bytes at lower addresses may also be
956 * written back.
957 *
958 * @param length
959 * the length in bytes of the region starting at address
960 * that must be guaranteed written back to memory.
961 *
962 * @throws RuntimeException if memory writeback is not supported
963 * on the current hardware of if the arguments are invalid.
964 * (<em>Note:</em> after optimization, invalid inputs may
965 * go undetected, which will lead to unpredictable
966 * behavior)
967 *
968 * @since 14
969 */
970
971 public void writebackMemory(long address, long length) {
972 checkWritebackEnabled();
973 checkWritebackMemory(address, length);
974
975 // perform any required pre-writeback barrier
976 writebackPreSync0();
977
978 // write back one cache line at a time
979 long line = dataCacheLineAlignDown(address);
980 long end = address + length;
981 while (line < end) {
982 writeback0(line);
983 line += dataCacheLineFlushSize();
984 }
985
986 // perform any required post-writeback barrier
987 writebackPostSync0();
988 }
989
990 /**
991 * Validate the arguments to writebackMemory
992 *
993 * @throws RuntimeException if the arguments are invalid
994 * (<em>Note:</em> after optimization, invalid inputs may
995 * go undetected, which will lead to unpredictable
996 * behavior)
997 */
998 private void checkWritebackMemory(long address, long length) {
999 checkNativeAddress(address);
1000 checkSize(length);
1001 }
1002
1003 /**
1004 * Validate that the current hardware supports memory writeback.
1005 * (<em>Note:</em> this is a belt and braces check. Clients are
1006 * expected to test whether writeback is enabled by calling
1007 * ({@link isWritebackEnabled #isWritebackEnabled} and avoid
1008 * calling method {@link writeback #writeback} if it is disabled).
1009 *
1010 *
1011 * @throws RuntimeException if memory writeback is not supported
1012 */
1013 private void checkWritebackEnabled() {
1014 if (!isWritebackEnabled()) {
1015 throw new RuntimeException("writebackMemory not enabled!");
1016 }
1017 }
1018
1019 /**
1020 * force writeback of an individual cache line.
1021 *
1022 * @param address
1023 * the start address of the cache line to be written back
1024 */
1025 @IntrinsicCandidate
1026 private native void writeback0(long address);
1027
1028 /**
1029 * Serialize writeback operations relative to preceding memory writes.
1030 */
1031 @IntrinsicCandidate
1032 private native void writebackPreSync0();
1033
1034 /**
1035 * Serialize writeback operations relative to following memory writes.
1036 */
1037 @IntrinsicCandidate
1038 private native void writebackPostSync0();
1039
1040 //--- random queries
1041
1042 /**
1043 * This constant differs from all results that will ever be returned from
1044 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1045 * or {@link #arrayBaseOffset}.
1046 * <p>
1047 * The static type is @code long} to emphasize that long arithmetic should
1048 * always be used for offset calculations to avoid overflows.
1049 */
1050 public static final long INVALID_FIELD_OFFSET = -1;
1051
1052 /**
1053 * Reports the location of a given field in the storage allocation of its
1054 * class. Do not expect to perform any sort of arithmetic on this offset;
1055 * it is just a cookie which is passed to the unsafe heap memory accessors.
1056 *
1057 * <p>Any given field will always have the same offset and base, and no
1058 * two distinct fields of the same class will ever have the same offset
1059 * and base.
1060 *
1061 * <p>As of 1.4.1, offsets for fields are represented as long values,
1062 * although the Sun JVM does not use the most significant 32 bits.
1063 * However, JVM implementations which store static fields at absolute
1064 * addresses can use long offsets and null base pointers to express
1065 * the field locations in a form usable by {@link #getInt(Object,long)}.
1066 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1067 * must preserve all bits of static field offsets.
1068 * @see #getInt(Object, long)
1069 */
1070 public long objectFieldOffset(Field f) {
1071 if (f == null) {
1072 throw new NullPointerException();
1073 }
1074
1075 return objectFieldOffset0(f);
1076 }
1077
1078 /**
1079 * Reports the location of the field with a given name in the storage
1080 * allocation of its class.
1081 *
1082 * @throws NullPointerException if any parameter is {@code null}.
1083 * @throws InternalError if there is no field named {@code name} declared
1084 * in class {@code c}, i.e., if {@code c.getDeclaredField(name)}
1085 * would throw {@code java.lang.NoSuchFieldException}.
1086 *
1087 * @see #objectFieldOffset(Field)
1088 */
1089 public long objectFieldOffset(Class<?> c, String name) {
1090 if (c == null || name == null) {
1091 throw new NullPointerException();
1092 }
1093
1094 return objectFieldOffset1(c, name);
1095 }
1096
1097 /**
1098 * Reports the location of a given static field, in conjunction with {@link
1099 * #staticFieldBase}.
1100 * <p>Do not expect to perform any sort of arithmetic on this offset;
1101 * it is just a cookie which is passed to the unsafe heap memory accessors.
1102 *
1103 * <p>Any given field will always have the same offset, and no two distinct
1104 * fields of the same class will ever have the same offset.
1105 *
1106 * <p>As of 1.4.1, offsets for fields are represented as long values,
1107 * although the Sun JVM does not use the most significant 32 bits.
1108 * It is hard to imagine a JVM technology which needs more than
1109 * a few bits to encode an offset within a non-array object,
1110 * However, for consistency with other methods in this class,
1111 * this method reports its result as a long value.
1112 * @see #getInt(Object, long)
1113 */
1114 public long staticFieldOffset(Field f) {
1115 if (f == null) {
1116 throw new NullPointerException();
1117 }
1118
1119 return staticFieldOffset0(f);
1120 }
1121
1122 /**
1123 * Reports the location of a given static field, in conjunction with {@link
1124 * #staticFieldOffset}.
1125 * <p>Fetch the base "Object", if any, with which static fields of the
1126 * given class can be accessed via methods like {@link #getInt(Object,
1127 * long)}. This value may be null. This value may refer to an object
1128 * which is a "cookie", not guaranteed to be a real Object, and it should
1129 * not be used in any way except as argument to the get and put routines in
1130 * this class.
1131 */
1132 public Object staticFieldBase(Field f) {
1133 if (f == null) {
1134 throw new NullPointerException();
1135 }
1136
1137 return staticFieldBase0(f);
1138 }
1139
1140 /**
1141 * Detects if the given class may need to be initialized. This is often
1142 * needed in conjunction with obtaining the static field base of a
1143 * class.
1144 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1145 */
1146 public boolean shouldBeInitialized(Class<?> c) {
1147 if (c == null) {
1148 throw new NullPointerException();
1149 }
1150
1151 return shouldBeInitialized0(c);
1152 }
1153
1154 /**
1155 * Ensures the given class has been initialized (see JVMS-5.5 for details).
1156 * This is often needed in conjunction with obtaining the static field base
1157 * of a class.
1158 *
1159 * The call returns when either class {@code c} is fully initialized or
1160 * class {@code c} is being initialized and the call is performed from
1161 * the initializing thread. In the latter case a subsequent call to
1162 * {@link #shouldBeInitialized} will return {@code true}.
1163 */
1164 public void ensureClassInitialized(Class<?> c) {
1165 if (c == null) {
1166 throw new NullPointerException();
1167 }
1168
1169 ensureClassInitialized0(c);
1170 }
1171
1172 /**
1173 * Reports the offset of the first element in the storage allocation of a
1174 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1175 * for the same class, you may use that scale factor, together with this
1176 * base offset, to form new offsets to access elements of arrays of the
1177 * given class.
1178 * <p>
1179 * The return value is in the range of a {@code int}. The return type is
1180 * {@code long} to emphasize that long arithmetic should always be used
1181 * for offset calculations to avoid overflows.
1182 *
1183 * @see #getInt(Object, long)
1184 * @see #putInt(Object, long, int)
1185 */
1186 public long arrayBaseOffset(Class<?> arrayClass) {
1187 if (arrayClass == null) {
1188 throw new NullPointerException();
1189 }
1190
1191 return arrayBaseOffset0(arrayClass);
1192 }
1193
1194
1195 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1196 public static final long ARRAY_BOOLEAN_BASE_OFFSET
1197 = theUnsafe.arrayBaseOffset(boolean[].class);
1198
1199 /** The value of {@code arrayBaseOffset(byte[].class)} */
1200 public static final long ARRAY_BYTE_BASE_OFFSET
1201 = theUnsafe.arrayBaseOffset(byte[].class);
1202
1203 /** The value of {@code arrayBaseOffset(short[].class)} */
1204 public static final long ARRAY_SHORT_BASE_OFFSET
1205 = theUnsafe.arrayBaseOffset(short[].class);
1206
1207 /** The value of {@code arrayBaseOffset(char[].class)} */
1208 public static final long ARRAY_CHAR_BASE_OFFSET
1209 = theUnsafe.arrayBaseOffset(char[].class);
1210
1211 /** The value of {@code arrayBaseOffset(int[].class)} */
1212 public static final long ARRAY_INT_BASE_OFFSET
1213 = theUnsafe.arrayBaseOffset(int[].class);
1214
1215 /** The value of {@code arrayBaseOffset(long[].class)} */
1216 public static final long ARRAY_LONG_BASE_OFFSET
1217 = theUnsafe.arrayBaseOffset(long[].class);
1218
1219 /** The value of {@code arrayBaseOffset(float[].class)} */
1220 public static final long ARRAY_FLOAT_BASE_OFFSET
1221 = theUnsafe.arrayBaseOffset(float[].class);
1222
1223 /** The value of {@code arrayBaseOffset(double[].class)} */
1224 public static final long ARRAY_DOUBLE_BASE_OFFSET
1225 = theUnsafe.arrayBaseOffset(double[].class);
1226
1227 /** The value of {@code arrayBaseOffset(Object[].class)} */
1228 public static final long ARRAY_OBJECT_BASE_OFFSET
1229 = theUnsafe.arrayBaseOffset(Object[].class);
1230
1231 /**
1232 * Reports the scale factor for addressing elements in the storage
1233 * allocation of a given array class. However, arrays of "narrow" types
1234 * will generally not work properly with accessors like {@link
1235 * #getByte(Object, long)}, so the scale factor for such classes is reported
1236 * as zero.
1237 * <p>
1238 * The computation of the actual memory offset should always use {@code
1239 * long} arithmetic to avoid overflows.
1240 *
1241 * @see #arrayBaseOffset
1242 * @see #getInt(Object, long)
1243 * @see #putInt(Object, long, int)
1244 */
1245 public int arrayIndexScale(Class<?> arrayClass) {
1246 if (arrayClass == null) {
1247 throw new NullPointerException();
1248 }
1249
1250 return arrayIndexScale0(arrayClass);
1251 }
1252
1253
1254 /** The value of {@code arrayIndexScale(boolean[].class)} */
1255 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1256 = theUnsafe.arrayIndexScale(boolean[].class);
1257
1258 /** The value of {@code arrayIndexScale(byte[].class)} */
1259 public static final int ARRAY_BYTE_INDEX_SCALE
1260 = theUnsafe.arrayIndexScale(byte[].class);
1261
1262 /** The value of {@code arrayIndexScale(short[].class)} */
1263 public static final int ARRAY_SHORT_INDEX_SCALE
1264 = theUnsafe.arrayIndexScale(short[].class);
1265
1266 /** The value of {@code arrayIndexScale(char[].class)} */
1267 public static final int ARRAY_CHAR_INDEX_SCALE
1268 = theUnsafe.arrayIndexScale(char[].class);
1269
1270 /** The value of {@code arrayIndexScale(int[].class)} */
1271 public static final int ARRAY_INT_INDEX_SCALE
1272 = theUnsafe.arrayIndexScale(int[].class);
1273
1274 /** The value of {@code arrayIndexScale(long[].class)} */
1275 public static final int ARRAY_LONG_INDEX_SCALE
1276 = theUnsafe.arrayIndexScale(long[].class);
1277
1278 /** The value of {@code arrayIndexScale(float[].class)} */
1279 public static final int ARRAY_FLOAT_INDEX_SCALE
1280 = theUnsafe.arrayIndexScale(float[].class);
1281
1282 /** The value of {@code arrayIndexScale(double[].class)} */
1283 public static final int ARRAY_DOUBLE_INDEX_SCALE
1284 = theUnsafe.arrayIndexScale(double[].class);
1285
1286 /** The value of {@code arrayIndexScale(Object[].class)} */
1287 public static final int ARRAY_OBJECT_INDEX_SCALE
1288 = theUnsafe.arrayIndexScale(Object[].class);
1289
1290 /**
1291 * Reports the size in bytes of a native pointer, as stored via {@link
1292 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1293 * other primitive types (as stored in native memory blocks) is determined
1294 * fully by their information content.
1295 */
1296 public int addressSize() {
1297 return ADDRESS_SIZE;
1298 }
1299
1300 /** The value of {@code addressSize()} */
1301 public static final int ADDRESS_SIZE = ADDRESS_SIZE0;
1302
1303 /**
1304 * Reports the size in bytes of a native memory page (whatever that is).
1305 * This value will always be a power of two.
1306 */
1307 public int pageSize() { return PAGE_SIZE; }
1308
1309 /**
1310 * Reports the size in bytes of a data cache line written back by
1311 * the hardware cache line flush operation available to the JVM or
1312 * 0 if data cache line flushing is not enabled.
1313 */
1314 public int dataCacheLineFlushSize() { return DATA_CACHE_LINE_FLUSH_SIZE; }
1315
1316 /**
1317 * Rounds down address to a data cache line boundary as
1318 * determined by {@link #dataCacheLineFlushSize}
1319 * @return the rounded down address
1320 */
1321 public long dataCacheLineAlignDown(long address) {
1322 return (address & ~(DATA_CACHE_LINE_FLUSH_SIZE - 1));
1323 }
1324
1325 /**
1326 * Returns true if data cache line writeback
1327 */
1328 public static boolean isWritebackEnabled() { return DATA_CACHE_LINE_FLUSH_SIZE != 0; }
1329
1330 //--- random trusted operations from JNI:
1331
1332 /**
1333 * Tells the VM to define a class, without security checks. By default, the
1334 * class loader and protection domain come from the caller's class.
1335 */
1336 public Class<?> defineClass(String name, byte[] b, int off, int len,
1337 ClassLoader loader,
1338 ProtectionDomain protectionDomain) {
1339 if (b == null) {
1340 throw new NullPointerException();
1341 }
1342 if (len < 0) {
1343 throw new ArrayIndexOutOfBoundsException();
1344 }
1345
1346 return defineClass0(name, b, off, len, loader, protectionDomain);
1347 }
1348
1349 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1350 ClassLoader loader,
1351 ProtectionDomain protectionDomain);
1352
1353 /**
1354 * Allocates an instance but does not run any constructor.
1355 * Initializes the class if it has not yet been.
1356 */
1357 @IntrinsicCandidate
1358 public native Object allocateInstance(Class<?> cls)
1359 throws InstantiationException;
1360
1361 /**
1362 * Allocates an array of a given type, but does not do zeroing.
1363 * <p>
1364 * This method should only be used in the very rare cases where a high-performance code
1365 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1366 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1367 * <p>
1368 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1369 * before allowing untrusted code, or code in other threads, to observe the reference
1370 * to the newly allocated array. In addition, the publication of the array reference must be
1371 * safe according to the Java Memory Model requirements.
1372 * <p>
1373 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1374 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1375 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1376 * or issuing a {@link #storeFence} before publishing the reference.
1377 * <p>
1378 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1379 * elements that could break heap integrity.
1380 *
1381 * @param componentType array component type to allocate
1382 * @param length array size to allocate
1383 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1384 * or the length is negative
1385 */
1386 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1387 if (componentType == null) {
1388 throw new IllegalArgumentException("Component type is null");
1389 }
1390 if (!componentType.isPrimitive()) {
1391 throw new IllegalArgumentException("Component type is not primitive");
1392 }
1393 if (length < 0) {
1394 throw new IllegalArgumentException("Negative length");
1395 }
1396 return allocateUninitializedArray0(componentType, length);
1397 }
1398
1399 @IntrinsicCandidate
1400 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1401 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1402 // return the zeroed arrays.
1403 if (componentType == byte.class) return new byte[length];
1404 if (componentType == boolean.class) return new boolean[length];
1405 if (componentType == short.class) return new short[length];
1406 if (componentType == char.class) return new char[length];
1407 if (componentType == int.class) return new int[length];
1408 if (componentType == float.class) return new float[length];
1409 if (componentType == long.class) return new long[length];
1410 if (componentType == double.class) return new double[length];
1411 return null;
1412 }
1413
1414 /** Throws the exception without telling the verifier. */
1415 public native void throwException(Throwable ee);
1416
1417 /**
1418 * Atomically updates Java variable to {@code x} if it is currently
1419 * holding {@code expected}.
1420 *
1421 * <p>This operation has memory semantics of a {@code volatile} read
1422 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1423 *
1424 * @return {@code true} if successful
1425 */
1426 @IntrinsicCandidate
1427 public final native boolean compareAndSetReference(Object o, long offset,
1428 Object expected,
1429 Object x);
1430
1431 @IntrinsicCandidate
1432 public final native Object compareAndExchangeReference(Object o, long offset,
1433 Object expected,
1434 Object x);
1435
1436 @IntrinsicCandidate
1437 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1438 Object expected,
1439 Object x) {
1440 return compareAndExchangeReference(o, offset, expected, x);
1441 }
1442
1443 @IntrinsicCandidate
1444 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1445 Object expected,
1446 Object x) {
1447 return compareAndExchangeReference(o, offset, expected, x);
1448 }
1449
1450 @IntrinsicCandidate
1451 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1452 Object expected,
1453 Object x) {
1454 return compareAndSetReference(o, offset, expected, x);
1455 }
1456
1457 @IntrinsicCandidate
1458 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1459 Object expected,
1460 Object x) {
1461 return compareAndSetReference(o, offset, expected, x);
1462 }
1463
1464 @IntrinsicCandidate
1465 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1466 Object expected,
1467 Object x) {
1468 return compareAndSetReference(o, offset, expected, x);
1469 }
1470
1471 @IntrinsicCandidate
1472 public final boolean weakCompareAndSetReference(Object o, long offset,
1473 Object expected,
1474 Object x) {
1475 return compareAndSetReference(o, offset, expected, x);
1476 }
1477
1478 /**
1479 * Atomically updates Java variable to {@code x} if it is currently
1480 * holding {@code expected}.
1481 *
1482 * <p>This operation has memory semantics of a {@code volatile} read
1483 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1484 *
1485 * @return {@code true} if successful
1486 */
1487 @IntrinsicCandidate
1488 public final native boolean compareAndSetInt(Object o, long offset,
1489 int expected,
1490 int x);
1491
1492 @IntrinsicCandidate
1493 public final native int compareAndExchangeInt(Object o, long offset,
1494 int expected,
1495 int x);
1496
1497 @IntrinsicCandidate
1498 public final int compareAndExchangeIntAcquire(Object o, long offset,
1499 int expected,
1500 int x) {
1501 return compareAndExchangeInt(o, offset, expected, x);
1502 }
1503
1504 @IntrinsicCandidate
1505 public final int compareAndExchangeIntRelease(Object o, long offset,
1506 int expected,
1507 int x) {
1508 return compareAndExchangeInt(o, offset, expected, x);
1509 }
1510
1511 @IntrinsicCandidate
1512 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1513 int expected,
1514 int x) {
1515 return compareAndSetInt(o, offset, expected, x);
1516 }
1517
1518 @IntrinsicCandidate
1519 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1520 int expected,
1521 int x) {
1522 return compareAndSetInt(o, offset, expected, x);
1523 }
1524
1525 @IntrinsicCandidate
1526 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1527 int expected,
1528 int x) {
1529 return compareAndSetInt(o, offset, expected, x);
1530 }
1531
1532 @IntrinsicCandidate
1533 public final boolean weakCompareAndSetInt(Object o, long offset,
1534 int expected,
1535 int x) {
1536 return compareAndSetInt(o, offset, expected, x);
1537 }
1538
1539 @IntrinsicCandidate
1540 public final byte compareAndExchangeByte(Object o, long offset,
1541 byte expected,
1542 byte x) {
1543 long wordOffset = offset & ~3;
1544 int shift = (int) (offset & 3) << 3;
1545 if (BIG_ENDIAN) {
1546 shift = 24 - shift;
1547 }
1548 int mask = 0xFF << shift;
1549 int maskedExpected = (expected & 0xFF) << shift;
1550 int maskedX = (x & 0xFF) << shift;
1551 int fullWord;
1552 do {
1553 fullWord = getIntVolatile(o, wordOffset);
1554 if ((fullWord & mask) != maskedExpected)
1555 return (byte) ((fullWord & mask) >> shift);
1556 } while (!weakCompareAndSetInt(o, wordOffset,
1557 fullWord, (fullWord & ~mask) | maskedX));
1558 return expected;
1559 }
1560
1561 @IntrinsicCandidate
1562 public final boolean compareAndSetByte(Object o, long offset,
1563 byte expected,
1564 byte x) {
1565 return compareAndExchangeByte(o, offset, expected, x) == expected;
1566 }
1567
1568 @IntrinsicCandidate
1569 public final boolean weakCompareAndSetByte(Object o, long offset,
1570 byte expected,
1571 byte x) {
1572 return compareAndSetByte(o, offset, expected, x);
1573 }
1574
1575 @IntrinsicCandidate
1576 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
1577 byte expected,
1578 byte x) {
1579 return weakCompareAndSetByte(o, offset, expected, x);
1580 }
1581
1582 @IntrinsicCandidate
1583 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
1584 byte expected,
1585 byte x) {
1586 return weakCompareAndSetByte(o, offset, expected, x);
1587 }
1588
1589 @IntrinsicCandidate
1590 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
1591 byte expected,
1592 byte x) {
1593 return weakCompareAndSetByte(o, offset, expected, x);
1594 }
1595
1596 @IntrinsicCandidate
1597 public final byte compareAndExchangeByteAcquire(Object o, long offset,
1598 byte expected,
1599 byte x) {
1600 return compareAndExchangeByte(o, offset, expected, x);
1601 }
1602
1603 @IntrinsicCandidate
1604 public final byte compareAndExchangeByteRelease(Object o, long offset,
1605 byte expected,
1606 byte x) {
1607 return compareAndExchangeByte(o, offset, expected, x);
1608 }
1609
1610 @IntrinsicCandidate
1611 public final short compareAndExchangeShort(Object o, long offset,
1612 short expected,
1613 short x) {
1614 if ((offset & 3) == 3) {
1615 throw new IllegalArgumentException("Update spans the word, not supported");
1616 }
1617 long wordOffset = offset & ~3;
1618 int shift = (int) (offset & 3) << 3;
1619 if (BIG_ENDIAN) {
1620 shift = 16 - shift;
1621 }
1622 int mask = 0xFFFF << shift;
1623 int maskedExpected = (expected & 0xFFFF) << shift;
1624 int maskedX = (x & 0xFFFF) << shift;
1625 int fullWord;
1626 do {
1627 fullWord = getIntVolatile(o, wordOffset);
1628 if ((fullWord & mask) != maskedExpected) {
1629 return (short) ((fullWord & mask) >> shift);
1630 }
1631 } while (!weakCompareAndSetInt(o, wordOffset,
1632 fullWord, (fullWord & ~mask) | maskedX));
1633 return expected;
1634 }
1635
1636 @IntrinsicCandidate
1637 public final boolean compareAndSetShort(Object o, long offset,
1638 short expected,
1639 short x) {
1640 return compareAndExchangeShort(o, offset, expected, x) == expected;
1641 }
1642
1643 @IntrinsicCandidate
1644 public final boolean weakCompareAndSetShort(Object o, long offset,
1645 short expected,
1646 short x) {
1647 return compareAndSetShort(o, offset, expected, x);
1648 }
1649
1650 @IntrinsicCandidate
1651 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
1652 short expected,
1653 short x) {
1654 return weakCompareAndSetShort(o, offset, expected, x);
1655 }
1656
1657 @IntrinsicCandidate
1658 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
1659 short expected,
1660 short x) {
1661 return weakCompareAndSetShort(o, offset, expected, x);
1662 }
1663
1664 @IntrinsicCandidate
1665 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
1666 short expected,
1667 short x) {
1668 return weakCompareAndSetShort(o, offset, expected, x);
1669 }
1670
1671
1672 @IntrinsicCandidate
1673 public final short compareAndExchangeShortAcquire(Object o, long offset,
1674 short expected,
1675 short x) {
1676 return compareAndExchangeShort(o, offset, expected, x);
1677 }
1678
1679 @IntrinsicCandidate
1680 public final short compareAndExchangeShortRelease(Object o, long offset,
1681 short expected,
1682 short x) {
1683 return compareAndExchangeShort(o, offset, expected, x);
1684 }
1685
1686 @ForceInline
1687 private char s2c(short s) {
1688 return (char) s;
1689 }
1690
1691 @ForceInline
1692 private short c2s(char s) {
1693 return (short) s;
1694 }
1695
1696 @ForceInline
1697 public final boolean compareAndSetChar(Object o, long offset,
1698 char expected,
1699 char x) {
1700 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
1701 }
1702
1703 @ForceInline
1704 public final char compareAndExchangeChar(Object o, long offset,
1705 char expected,
1706 char x) {
1707 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
1708 }
1709
1710 @ForceInline
1711 public final char compareAndExchangeCharAcquire(Object o, long offset,
1712 char expected,
1713 char x) {
1714 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
1715 }
1716
1717 @ForceInline
1718 public final char compareAndExchangeCharRelease(Object o, long offset,
1719 char expected,
1720 char x) {
1721 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
1722 }
1723
1724 @ForceInline
1725 public final boolean weakCompareAndSetChar(Object o, long offset,
1726 char expected,
1727 char x) {
1728 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
1729 }
1730
1731 @ForceInline
1732 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
1733 char expected,
1734 char x) {
1735 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
1736 }
1737
1738 @ForceInline
1739 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
1740 char expected,
1741 char x) {
1742 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
1743 }
1744
1745 @ForceInline
1746 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
1747 char expected,
1748 char x) {
1749 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
1750 }
1751
1752 /**
1753 * The JVM converts integral values to boolean values using two
1754 * different conventions, byte testing against zero and truncation
1755 * to least-significant bit.
1756 *
1757 * <p>The JNI documents specify that, at least for returning
1758 * values from native methods, a Java boolean value is converted
1759 * to the value-set 0..1 by first truncating to a byte (0..255 or
1760 * maybe -128..127) and then testing against zero. Thus, Java
1761 * booleans in non-Java data structures are by convention
1762 * represented as 8-bit containers containing either zero (for
1763 * false) or any non-zero value (for true).
1764 *
1765 * <p>Java booleans in the heap are also stored in bytes, but are
1766 * strongly normalized to the value-set 0..1 (i.e., they are
1767 * truncated to the least-significant bit).
1768 *
1769 * <p>The main reason for having different conventions for
1770 * conversion is performance: Truncation to the least-significant
1771 * bit can be usually implemented with fewer (machine)
1772 * instructions than byte testing against zero.
1773 *
1774 * <p>A number of Unsafe methods load boolean values from the heap
1775 * as bytes. Unsafe converts those values according to the JNI
1776 * rules (i.e, using the "testing against zero" convention). The
1777 * method {@code byte2bool} implements that conversion.
1778 *
1779 * @param b the byte to be converted to boolean
1780 * @return the result of the conversion
1781 */
1782 @ForceInline
1783 private boolean byte2bool(byte b) {
1784 return b != 0;
1785 }
1786
1787 /**
1788 * Convert a boolean value to a byte. The return value is strongly
1789 * normalized to the value-set 0..1 (i.e., the value is truncated
1790 * to the least-significant bit). See {@link #byte2bool(byte)} for
1791 * more details on conversion conventions.
1792 *
1793 * @param b the boolean to be converted to byte (and then normalized)
1794 * @return the result of the conversion
1795 */
1796 @ForceInline
1797 private byte bool2byte(boolean b) {
1798 return b ? (byte)1 : (byte)0;
1799 }
1800
1801 @ForceInline
1802 public final boolean compareAndSetBoolean(Object o, long offset,
1803 boolean expected,
1804 boolean x) {
1805 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1806 }
1807
1808 @ForceInline
1809 public final boolean compareAndExchangeBoolean(Object o, long offset,
1810 boolean expected,
1811 boolean x) {
1812 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
1813 }
1814
1815 @ForceInline
1816 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
1817 boolean expected,
1818 boolean x) {
1819 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
1820 }
1821
1822 @ForceInline
1823 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
1824 boolean expected,
1825 boolean x) {
1826 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
1827 }
1828
1829 @ForceInline
1830 public final boolean weakCompareAndSetBoolean(Object o, long offset,
1831 boolean expected,
1832 boolean x) {
1833 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1834 }
1835
1836 @ForceInline
1837 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
1838 boolean expected,
1839 boolean x) {
1840 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
1841 }
1842
1843 @ForceInline
1844 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
1845 boolean expected,
1846 boolean x) {
1847 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
1848 }
1849
1850 @ForceInline
1851 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
1852 boolean expected,
1853 boolean x) {
1854 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
1855 }
1856
1857 /**
1858 * Atomically updates Java variable to {@code x} if it is currently
1859 * holding {@code expected}.
1860 *
1861 * <p>This operation has memory semantics of a {@code volatile} read
1862 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1863 *
1864 * @return {@code true} if successful
1865 */
1866 @ForceInline
1867 public final boolean compareAndSetFloat(Object o, long offset,
1868 float expected,
1869 float x) {
1870 return compareAndSetInt(o, offset,
1871 Float.floatToRawIntBits(expected),
1872 Float.floatToRawIntBits(x));
1873 }
1874
1875 @ForceInline
1876 public final float compareAndExchangeFloat(Object o, long offset,
1877 float expected,
1878 float x) {
1879 int w = compareAndExchangeInt(o, offset,
1880 Float.floatToRawIntBits(expected),
1881 Float.floatToRawIntBits(x));
1882 return Float.intBitsToFloat(w);
1883 }
1884
1885 @ForceInline
1886 public final float compareAndExchangeFloatAcquire(Object o, long offset,
1887 float expected,
1888 float x) {
1889 int w = compareAndExchangeIntAcquire(o, offset,
1890 Float.floatToRawIntBits(expected),
1891 Float.floatToRawIntBits(x));
1892 return Float.intBitsToFloat(w);
1893 }
1894
1895 @ForceInline
1896 public final float compareAndExchangeFloatRelease(Object o, long offset,
1897 float expected,
1898 float x) {
1899 int w = compareAndExchangeIntRelease(o, offset,
1900 Float.floatToRawIntBits(expected),
1901 Float.floatToRawIntBits(x));
1902 return Float.intBitsToFloat(w);
1903 }
1904
1905 @ForceInline
1906 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
1907 float expected,
1908 float x) {
1909 return weakCompareAndSetIntPlain(o, offset,
1910 Float.floatToRawIntBits(expected),
1911 Float.floatToRawIntBits(x));
1912 }
1913
1914 @ForceInline
1915 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
1916 float expected,
1917 float x) {
1918 return weakCompareAndSetIntAcquire(o, offset,
1919 Float.floatToRawIntBits(expected),
1920 Float.floatToRawIntBits(x));
1921 }
1922
1923 @ForceInline
1924 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
1925 float expected,
1926 float x) {
1927 return weakCompareAndSetIntRelease(o, offset,
1928 Float.floatToRawIntBits(expected),
1929 Float.floatToRawIntBits(x));
1930 }
1931
1932 @ForceInline
1933 public final boolean weakCompareAndSetFloat(Object o, long offset,
1934 float expected,
1935 float x) {
1936 return weakCompareAndSetInt(o, offset,
1937 Float.floatToRawIntBits(expected),
1938 Float.floatToRawIntBits(x));
1939 }
1940
1941 /**
1942 * Atomically updates Java variable to {@code x} if it is currently
1943 * holding {@code expected}.
1944 *
1945 * <p>This operation has memory semantics of a {@code volatile} read
1946 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1947 *
1948 * @return {@code true} if successful
1949 */
1950 @ForceInline
1951 public final boolean compareAndSetDouble(Object o, long offset,
1952 double expected,
1953 double x) {
1954 return compareAndSetLong(o, offset,
1955 Double.doubleToRawLongBits(expected),
1956 Double.doubleToRawLongBits(x));
1957 }
1958
1959 @ForceInline
1960 public final double compareAndExchangeDouble(Object o, long offset,
1961 double expected,
1962 double x) {
1963 long w = compareAndExchangeLong(o, offset,
1964 Double.doubleToRawLongBits(expected),
1965 Double.doubleToRawLongBits(x));
1966 return Double.longBitsToDouble(w);
1967 }
1968
1969 @ForceInline
1970 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
1971 double expected,
1972 double x) {
1973 long w = compareAndExchangeLongAcquire(o, offset,
1974 Double.doubleToRawLongBits(expected),
1975 Double.doubleToRawLongBits(x));
1976 return Double.longBitsToDouble(w);
1977 }
1978
1979 @ForceInline
1980 public final double compareAndExchangeDoubleRelease(Object o, long offset,
1981 double expected,
1982 double x) {
1983 long w = compareAndExchangeLongRelease(o, offset,
1984 Double.doubleToRawLongBits(expected),
1985 Double.doubleToRawLongBits(x));
1986 return Double.longBitsToDouble(w);
1987 }
1988
1989 @ForceInline
1990 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
1991 double expected,
1992 double x) {
1993 return weakCompareAndSetLongPlain(o, offset,
1994 Double.doubleToRawLongBits(expected),
1995 Double.doubleToRawLongBits(x));
1996 }
1997
1998 @ForceInline
1999 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
2000 double expected,
2001 double x) {
2002 return weakCompareAndSetLongAcquire(o, offset,
2003 Double.doubleToRawLongBits(expected),
2004 Double.doubleToRawLongBits(x));
2005 }
2006
2007 @ForceInline
2008 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
2009 double expected,
2010 double x) {
2011 return weakCompareAndSetLongRelease(o, offset,
2012 Double.doubleToRawLongBits(expected),
2013 Double.doubleToRawLongBits(x));
2014 }
2015
2016 @ForceInline
2017 public final boolean weakCompareAndSetDouble(Object o, long offset,
2018 double expected,
2019 double x) {
2020 return weakCompareAndSetLong(o, offset,
2021 Double.doubleToRawLongBits(expected),
2022 Double.doubleToRawLongBits(x));
2023 }
2024
2025 /**
2026 * Atomically updates Java variable to {@code x} if it is currently
2027 * holding {@code expected}.
2028 *
2029 * <p>This operation has memory semantics of a {@code volatile} read
2030 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2031 *
2032 * @return {@code true} if successful
2033 */
2034 @IntrinsicCandidate
2035 public final native boolean compareAndSetLong(Object o, long offset,
2036 long expected,
2037 long x);
2038
2039 @IntrinsicCandidate
2040 public final native long compareAndExchangeLong(Object o, long offset,
2041 long expected,
2042 long x);
2043
2044 @IntrinsicCandidate
2045 public final long compareAndExchangeLongAcquire(Object o, long offset,
2046 long expected,
2047 long x) {
2048 return compareAndExchangeLong(o, offset, expected, x);
2049 }
2050
2051 @IntrinsicCandidate
2052 public final long compareAndExchangeLongRelease(Object o, long offset,
2053 long expected,
2054 long x) {
2055 return compareAndExchangeLong(o, offset, expected, x);
2056 }
2057
2058 @IntrinsicCandidate
2059 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2060 long expected,
2061 long x) {
2062 return compareAndSetLong(o, offset, expected, x);
2063 }
2064
2065 @IntrinsicCandidate
2066 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2067 long expected,
2068 long x) {
2069 return compareAndSetLong(o, offset, expected, x);
2070 }
2071
2072 @IntrinsicCandidate
2073 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2074 long expected,
2075 long x) {
2076 return compareAndSetLong(o, offset, expected, x);
2077 }
2078
2079 @IntrinsicCandidate
2080 public final boolean weakCompareAndSetLong(Object o, long offset,
2081 long expected,
2082 long x) {
2083 return compareAndSetLong(o, offset, expected, x);
2084 }
2085
2086 /**
2087 * Fetches a reference value from a given Java variable, with volatile
2088 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2089 */
2090 @IntrinsicCandidate
2091 public native Object getReferenceVolatile(Object o, long offset);
2092
2093 /**
2094 * Stores a reference value into a given Java variable, with
2095 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2096 */
2097 @IntrinsicCandidate
2098 public native void putReferenceVolatile(Object o, long offset, Object x);
2099
2100 /** Volatile version of {@link #getInt(Object, long)} */
2101 @IntrinsicCandidate
2102 public native int getIntVolatile(Object o, long offset);
2103
2104 /** Volatile version of {@link #putInt(Object, long, int)} */
2105 @IntrinsicCandidate
2106 public native void putIntVolatile(Object o, long offset, int x);
2107
2108 /** Volatile version of {@link #getBoolean(Object, long)} */
2109 @IntrinsicCandidate
2110 public native boolean getBooleanVolatile(Object o, long offset);
2111
2112 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2113 @IntrinsicCandidate
2114 public native void putBooleanVolatile(Object o, long offset, boolean x);
2115
2116 /** Volatile version of {@link #getByte(Object, long)} */
2117 @IntrinsicCandidate
2118 public native byte getByteVolatile(Object o, long offset);
2119
2120 /** Volatile version of {@link #putByte(Object, long, byte)} */
2121 @IntrinsicCandidate
2122 public native void putByteVolatile(Object o, long offset, byte x);
2123
2124 /** Volatile version of {@link #getShort(Object, long)} */
2125 @IntrinsicCandidate
2126 public native short getShortVolatile(Object o, long offset);
2127
2128 /** Volatile version of {@link #putShort(Object, long, short)} */
2129 @IntrinsicCandidate
2130 public native void putShortVolatile(Object o, long offset, short x);
2131
2132 /** Volatile version of {@link #getChar(Object, long)} */
2133 @IntrinsicCandidate
2134 public native char getCharVolatile(Object o, long offset);
2135
2136 /** Volatile version of {@link #putChar(Object, long, char)} */
2137 @IntrinsicCandidate
2138 public native void putCharVolatile(Object o, long offset, char x);
2139
2140 /** Volatile version of {@link #getLong(Object, long)} */
2141 @IntrinsicCandidate
2142 public native long getLongVolatile(Object o, long offset);
2143
2144 /** Volatile version of {@link #putLong(Object, long, long)} */
2145 @IntrinsicCandidate
2146 public native void putLongVolatile(Object o, long offset, long x);
2147
2148 /** Volatile version of {@link #getFloat(Object, long)} */
2149 @IntrinsicCandidate
2150 public native float getFloatVolatile(Object o, long offset);
2151
2152 /** Volatile version of {@link #putFloat(Object, long, float)} */
2153 @IntrinsicCandidate
2154 public native void putFloatVolatile(Object o, long offset, float x);
2155
2156 /** Volatile version of {@link #getDouble(Object, long)} */
2157 @IntrinsicCandidate
2158 public native double getDoubleVolatile(Object o, long offset);
2159
2160 /** Volatile version of {@link #putDouble(Object, long, double)} */
2161 @IntrinsicCandidate
2162 public native void putDoubleVolatile(Object o, long offset, double x);
2163
2164
2165
2166 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2167 @IntrinsicCandidate
2168 public final Object getReferenceAcquire(Object o, long offset) {
2169 return getReferenceVolatile(o, offset);
2170 }
2171
2172 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2173 @IntrinsicCandidate
2174 public final boolean getBooleanAcquire(Object o, long offset) {
2175 return getBooleanVolatile(o, offset);
2176 }
2177
2178 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2179 @IntrinsicCandidate
2180 public final byte getByteAcquire(Object o, long offset) {
2181 return getByteVolatile(o, offset);
2182 }
2183
2184 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2185 @IntrinsicCandidate
2186 public final short getShortAcquire(Object o, long offset) {
2187 return getShortVolatile(o, offset);
2188 }
2189
2190 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2191 @IntrinsicCandidate
2192 public final char getCharAcquire(Object o, long offset) {
2193 return getCharVolatile(o, offset);
2194 }
2195
2196 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2197 @IntrinsicCandidate
2198 public final int getIntAcquire(Object o, long offset) {
2199 return getIntVolatile(o, offset);
2200 }
2201
2202 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2203 @IntrinsicCandidate
2204 public final float getFloatAcquire(Object o, long offset) {
2205 return getFloatVolatile(o, offset);
2206 }
2207
2208 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2209 @IntrinsicCandidate
2210 public final long getLongAcquire(Object o, long offset) {
2211 return getLongVolatile(o, offset);
2212 }
2213
2214 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2215 @IntrinsicCandidate
2216 public final double getDoubleAcquire(Object o, long offset) {
2217 return getDoubleVolatile(o, offset);
2218 }
2219
2220 /*
2221 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2222 * that do not guarantee immediate visibility of the store to
2223 * other threads. This method is generally only useful if the
2224 * underlying field is a Java volatile (or if an array cell, one
2225 * that is otherwise only accessed using volatile accesses).
2226 *
2227 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2228 */
2229
2230 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2231 @IntrinsicCandidate
2232 public final void putReferenceRelease(Object o, long offset, Object x) {
2233 putReferenceVolatile(o, offset, x);
2234 }
2235
2236 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2237 @IntrinsicCandidate
2238 public final void putBooleanRelease(Object o, long offset, boolean x) {
2239 putBooleanVolatile(o, offset, x);
2240 }
2241
2242 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2243 @IntrinsicCandidate
2244 public final void putByteRelease(Object o, long offset, byte x) {
2245 putByteVolatile(o, offset, x);
2246 }
2247
2248 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2249 @IntrinsicCandidate
2250 public final void putShortRelease(Object o, long offset, short x) {
2251 putShortVolatile(o, offset, x);
2252 }
2253
2254 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2255 @IntrinsicCandidate
2256 public final void putCharRelease(Object o, long offset, char x) {
2257 putCharVolatile(o, offset, x);
2258 }
2259
2260 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2261 @IntrinsicCandidate
2262 public final void putIntRelease(Object o, long offset, int x) {
2263 putIntVolatile(o, offset, x);
2264 }
2265
2266 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2267 @IntrinsicCandidate
2268 public final void putFloatRelease(Object o, long offset, float x) {
2269 putFloatVolatile(o, offset, x);
2270 }
2271
2272 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2273 @IntrinsicCandidate
2274 public final void putLongRelease(Object o, long offset, long x) {
2275 putLongVolatile(o, offset, x);
2276 }
2277
2278 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2279 @IntrinsicCandidate
2280 public final void putDoubleRelease(Object o, long offset, double x) {
2281 putDoubleVolatile(o, offset, x);
2282 }
2283
2284 // ------------------------------ Opaque --------------------------------------
2285
2286 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2287 @IntrinsicCandidate
2288 public final Object getReferenceOpaque(Object o, long offset) {
2289 return getReferenceVolatile(o, offset);
2290 }
2291
2292 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2293 @IntrinsicCandidate
2294 public final boolean getBooleanOpaque(Object o, long offset) {
2295 return getBooleanVolatile(o, offset);
2296 }
2297
2298 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2299 @IntrinsicCandidate
2300 public final byte getByteOpaque(Object o, long offset) {
2301 return getByteVolatile(o, offset);
2302 }
2303
2304 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2305 @IntrinsicCandidate
2306 public final short getShortOpaque(Object o, long offset) {
2307 return getShortVolatile(o, offset);
2308 }
2309
2310 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2311 @IntrinsicCandidate
2312 public final char getCharOpaque(Object o, long offset) {
2313 return getCharVolatile(o, offset);
2314 }
2315
2316 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2317 @IntrinsicCandidate
2318 public final int getIntOpaque(Object o, long offset) {
2319 return getIntVolatile(o, offset);
2320 }
2321
2322 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2323 @IntrinsicCandidate
2324 public final float getFloatOpaque(Object o, long offset) {
2325 return getFloatVolatile(o, offset);
2326 }
2327
2328 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2329 @IntrinsicCandidate
2330 public final long getLongOpaque(Object o, long offset) {
2331 return getLongVolatile(o, offset);
2332 }
2333
2334 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2335 @IntrinsicCandidate
2336 public final double getDoubleOpaque(Object o, long offset) {
2337 return getDoubleVolatile(o, offset);
2338 }
2339
2340 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2341 @IntrinsicCandidate
2342 public final void putReferenceOpaque(Object o, long offset, Object x) {
2343 putReferenceVolatile(o, offset, x);
2344 }
2345
2346 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2347 @IntrinsicCandidate
2348 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2349 putBooleanVolatile(o, offset, x);
2350 }
2351
2352 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2353 @IntrinsicCandidate
2354 public final void putByteOpaque(Object o, long offset, byte x) {
2355 putByteVolatile(o, offset, x);
2356 }
2357
2358 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2359 @IntrinsicCandidate
2360 public final void putShortOpaque(Object o, long offset, short x) {
2361 putShortVolatile(o, offset, x);
2362 }
2363
2364 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2365 @IntrinsicCandidate
2366 public final void putCharOpaque(Object o, long offset, char x) {
2367 putCharVolatile(o, offset, x);
2368 }
2369
2370 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2371 @IntrinsicCandidate
2372 public final void putIntOpaque(Object o, long offset, int x) {
2373 putIntVolatile(o, offset, x);
2374 }
2375
2376 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2377 @IntrinsicCandidate
2378 public final void putFloatOpaque(Object o, long offset, float x) {
2379 putFloatVolatile(o, offset, x);
2380 }
2381
2382 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2383 @IntrinsicCandidate
2384 public final void putLongOpaque(Object o, long offset, long x) {
2385 putLongVolatile(o, offset, x);
2386 }
2387
2388 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2389 @IntrinsicCandidate
2390 public final void putDoubleOpaque(Object o, long offset, double x) {
2391 putDoubleVolatile(o, offset, x);
2392 }
2393
2394 /**
2395 * Unblocks the given thread blocked on {@code park}, or, if it is
2396 * not blocked, causes the subsequent call to {@code park} not to
2397 * block. Note: this operation is "unsafe" solely because the
2398 * caller must somehow ensure that the thread has not been
2399 * destroyed. Nothing special is usually required to ensure this
2400 * when called from Java (in which there will ordinarily be a live
2401 * reference to the thread) but this is not nearly-automatically
2402 * so when calling from native code.
2403 *
2404 * @param thread the thread to unpark.
2405 */
2406 @IntrinsicCandidate
2407 public native void unpark(Object thread);
2408
2409 /**
2410 * Blocks current thread, returning when a balancing
2411 * {@code unpark} occurs, or a balancing {@code unpark} has
2412 * already occurred, or the thread is interrupted, or, if not
2413 * absolute and time is not zero, the given time nanoseconds have
2414 * elapsed, or if absolute, the given deadline in milliseconds
2415 * since Epoch has passed, or spuriously (i.e., returning for no
2416 * "reason"). Note: This operation is in the Unsafe class only
2417 * because {@code unpark} is, so it would be strange to place it
2418 * elsewhere.
2419 */
2420 @IntrinsicCandidate
2421 public native void park(boolean isAbsolute, long time);
2422
2423 /**
2424 * Gets the load average in the system run queue assigned
2425 * to the available processors averaged over various periods of time.
2426 * This method retrieves the given {@code nelem} samples and
2427 * assigns to the elements of the given {@code loadavg} array.
2428 * The system imposes a maximum of 3 samples, representing
2429 * averages over the last 1, 5, and 15 minutes, respectively.
2430 *
2431 * @param loadavg an array of double of size nelems
2432 * @param nelems the number of samples to be retrieved and
2433 * must be 1 to 3.
2434 *
2435 * @return the number of samples actually retrieved; or -1
2436 * if the load average is unobtainable.
2437 */
2438 public int getLoadAverage(double[] loadavg, int nelems) {
2439 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2440 throw new ArrayIndexOutOfBoundsException();
2441 }
2442
2443 return getLoadAverage0(loadavg, nelems);
2444 }
2445
2446 // The following contain CAS-based Java implementations used on
2447 // platforms not supporting native instructions
2448
2449 /**
2450 * Atomically adds the given value to the current value of a field
2451 * or array element within the given object {@code o}
2452 * at the given {@code offset}.
2453 *
2454 * @param o object/array to update the field/element in
2455 * @param offset field/element offset
2456 * @param delta the value to add
2457 * @return the previous value
2458 * @since 1.8
2459 */
2460 @IntrinsicCandidate
2461 public final int getAndAddInt(Object o, long offset, int delta) {
2462 int v;
2463 do {
2464 v = getIntVolatile(o, offset);
2465 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
2466 return v;
2467 }
2468
2469 @ForceInline
2470 public final int getAndAddIntRelease(Object o, long offset, int delta) {
2471 int v;
2472 do {
2473 v = getInt(o, offset);
2474 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
2475 return v;
2476 }
2477
2478 @ForceInline
2479 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
2480 int v;
2481 do {
2482 v = getIntAcquire(o, offset);
2483 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
2484 return v;
2485 }
2486
2487 /**
2488 * Atomically adds the given value to the current value of a field
2489 * or array element within the given object {@code o}
2490 * at the given {@code offset}.
2491 *
2492 * @param o object/array to update the field/element in
2493 * @param offset field/element offset
2494 * @param delta the value to add
2495 * @return the previous value
2496 * @since 1.8
2497 */
2498 @IntrinsicCandidate
2499 public final long getAndAddLong(Object o, long offset, long delta) {
2500 long v;
2501 do {
2502 v = getLongVolatile(o, offset);
2503 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
2504 return v;
2505 }
2506
2507 @ForceInline
2508 public final long getAndAddLongRelease(Object o, long offset, long delta) {
2509 long v;
2510 do {
2511 v = getLong(o, offset);
2512 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
2513 return v;
2514 }
2515
2516 @ForceInline
2517 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
2518 long v;
2519 do {
2520 v = getLongAcquire(o, offset);
2521 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
2522 return v;
2523 }
2524
2525 @IntrinsicCandidate
2526 public final byte getAndAddByte(Object o, long offset, byte delta) {
2527 byte v;
2528 do {
2529 v = getByteVolatile(o, offset);
2530 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
2531 return v;
2532 }
2533
2534 @ForceInline
2535 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
2536 byte v;
2537 do {
2538 v = getByte(o, offset);
2539 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
2540 return v;
2541 }
2542
2543 @ForceInline
2544 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
2545 byte v;
2546 do {
2547 v = getByteAcquire(o, offset);
2548 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
2549 return v;
2550 }
2551
2552 @IntrinsicCandidate
2553 public final short getAndAddShort(Object o, long offset, short delta) {
2554 short v;
2555 do {
2556 v = getShortVolatile(o, offset);
2557 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
2558 return v;
2559 }
2560
2561 @ForceInline
2562 public final short getAndAddShortRelease(Object o, long offset, short delta) {
2563 short v;
2564 do {
2565 v = getShort(o, offset);
2566 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
2567 return v;
2568 }
2569
2570 @ForceInline
2571 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
2572 short v;
2573 do {
2574 v = getShortAcquire(o, offset);
2575 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
2576 return v;
2577 }
2578
2579 @ForceInline
2580 public final char getAndAddChar(Object o, long offset, char delta) {
2581 return (char) getAndAddShort(o, offset, (short) delta);
2582 }
2583
2584 @ForceInline
2585 public final char getAndAddCharRelease(Object o, long offset, char delta) {
2586 return (char) getAndAddShortRelease(o, offset, (short) delta);
2587 }
2588
2589 @ForceInline
2590 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
2591 return (char) getAndAddShortAcquire(o, offset, (short) delta);
2592 }
2593
2594 @ForceInline
2595 public final float getAndAddFloat(Object o, long offset, float delta) {
2596 int expectedBits;
2597 float v;
2598 do {
2599 // Load and CAS with the raw bits to avoid issues with NaNs and
2600 // possible bit conversion from signaling NaNs to quiet NaNs that
2601 // may result in the loop not terminating.
2602 expectedBits = getIntVolatile(o, offset);
2603 v = Float.intBitsToFloat(expectedBits);
2604 } while (!weakCompareAndSetInt(o, offset,
2605 expectedBits, Float.floatToRawIntBits(v + delta)));
2606 return v;
2607 }
2608
2609 @ForceInline
2610 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
2611 int expectedBits;
2612 float v;
2613 do {
2614 // Load and CAS with the raw bits to avoid issues with NaNs and
2615 // possible bit conversion from signaling NaNs to quiet NaNs that
2616 // may result in the loop not terminating.
2617 expectedBits = getInt(o, offset);
2618 v = Float.intBitsToFloat(expectedBits);
2619 } while (!weakCompareAndSetIntRelease(o, offset,
2620 expectedBits, Float.floatToRawIntBits(v + delta)));
2621 return v;
2622 }
2623
2624 @ForceInline
2625 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
2626 int expectedBits;
2627 float v;
2628 do {
2629 // Load and CAS with the raw bits to avoid issues with NaNs and
2630 // possible bit conversion from signaling NaNs to quiet NaNs that
2631 // may result in the loop not terminating.
2632 expectedBits = getIntAcquire(o, offset);
2633 v = Float.intBitsToFloat(expectedBits);
2634 } while (!weakCompareAndSetIntAcquire(o, offset,
2635 expectedBits, Float.floatToRawIntBits(v + delta)));
2636 return v;
2637 }
2638
2639 @ForceInline
2640 public final double getAndAddDouble(Object o, long offset, double delta) {
2641 long expectedBits;
2642 double v;
2643 do {
2644 // Load and CAS with the raw bits to avoid issues with NaNs and
2645 // possible bit conversion from signaling NaNs to quiet NaNs that
2646 // may result in the loop not terminating.
2647 expectedBits = getLongVolatile(o, offset);
2648 v = Double.longBitsToDouble(expectedBits);
2649 } while (!weakCompareAndSetLong(o, offset,
2650 expectedBits, Double.doubleToRawLongBits(v + delta)));
2651 return v;
2652 }
2653
2654 @ForceInline
2655 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
2656 long expectedBits;
2657 double v;
2658 do {
2659 // Load and CAS with the raw bits to avoid issues with NaNs and
2660 // possible bit conversion from signaling NaNs to quiet NaNs that
2661 // may result in the loop not terminating.
2662 expectedBits = getLong(o, offset);
2663 v = Double.longBitsToDouble(expectedBits);
2664 } while (!weakCompareAndSetLongRelease(o, offset,
2665 expectedBits, Double.doubleToRawLongBits(v + delta)));
2666 return v;
2667 }
2668
2669 @ForceInline
2670 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
2671 long expectedBits;
2672 double v;
2673 do {
2674 // Load and CAS with the raw bits to avoid issues with NaNs and
2675 // possible bit conversion from signaling NaNs to quiet NaNs that
2676 // may result in the loop not terminating.
2677 expectedBits = getLongAcquire(o, offset);
2678 v = Double.longBitsToDouble(expectedBits);
2679 } while (!weakCompareAndSetLongAcquire(o, offset,
2680 expectedBits, Double.doubleToRawLongBits(v + delta)));
2681 return v;
2682 }
2683
2684 /**
2685 * Atomically exchanges the given value with the current value of
2686 * a field or array element within the given object {@code o}
2687 * at the given {@code offset}.
2688 *
2689 * @param o object/array to update the field/element in
2690 * @param offset field/element offset
2691 * @param newValue new value
2692 * @return the previous value
2693 * @since 1.8
2694 */
2695 @IntrinsicCandidate
2696 public final int getAndSetInt(Object o, long offset, int newValue) {
2697 int v;
2698 do {
2699 v = getIntVolatile(o, offset);
2700 } while (!weakCompareAndSetInt(o, offset, v, newValue));
2701 return v;
2702 }
2703
2704 @ForceInline
2705 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
2706 int v;
2707 do {
2708 v = getInt(o, offset);
2709 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
2710 return v;
2711 }
2712
2713 @ForceInline
2714 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
2715 int v;
2716 do {
2717 v = getIntAcquire(o, offset);
2718 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
2719 return v;
2720 }
2721
2722 /**
2723 * Atomically exchanges the given value with the current value of
2724 * a field or array element within the given object {@code o}
2725 * at the given {@code offset}.
2726 *
2727 * @param o object/array to update the field/element in
2728 * @param offset field/element offset
2729 * @param newValue new value
2730 * @return the previous value
2731 * @since 1.8
2732 */
2733 @IntrinsicCandidate
2734 public final long getAndSetLong(Object o, long offset, long newValue) {
2735 long v;
2736 do {
2737 v = getLongVolatile(o, offset);
2738 } while (!weakCompareAndSetLong(o, offset, v, newValue));
2739 return v;
2740 }
2741
2742 @ForceInline
2743 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
2744 long v;
2745 do {
2746 v = getLong(o, offset);
2747 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
2748 return v;
2749 }
2750
2751 @ForceInline
2752 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
2753 long v;
2754 do {
2755 v = getLongAcquire(o, offset);
2756 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
2757 return v;
2758 }
2759
2760 /**
2761 * Atomically exchanges the given reference value with the current
2762 * reference value of a field or array element within the given
2763 * object {@code o} at the given {@code offset}.
2764 *
2765 * @param o object/array to update the field/element in
2766 * @param offset field/element offset
2767 * @param newValue new value
2768 * @return the previous value
2769 * @since 1.8
2770 */
2771 @IntrinsicCandidate
2772 public final Object getAndSetReference(Object o, long offset, Object newValue) {
2773 Object v;
2774 do {
2775 v = getReferenceVolatile(o, offset);
2776 } while (!weakCompareAndSetReference(o, offset, v, newValue));
2777 return v;
2778 }
2779
2780 @ForceInline
2781 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
2782 Object v;
2783 do {
2784 v = getReference(o, offset);
2785 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
2786 return v;
2787 }
2788
2789 @ForceInline
2790 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
2791 Object v;
2792 do {
2793 v = getReferenceAcquire(o, offset);
2794 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
2795 return v;
2796 }
2797
2798 @IntrinsicCandidate
2799 public final byte getAndSetByte(Object o, long offset, byte newValue) {
2800 byte v;
2801 do {
2802 v = getByteVolatile(o, offset);
2803 } while (!weakCompareAndSetByte(o, offset, v, newValue));
2804 return v;
2805 }
2806
2807 @ForceInline
2808 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
2809 byte v;
2810 do {
2811 v = getByte(o, offset);
2812 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
2813 return v;
2814 }
2815
2816 @ForceInline
2817 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
2818 byte v;
2819 do {
2820 v = getByteAcquire(o, offset);
2821 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
2822 return v;
2823 }
2824
2825 @ForceInline
2826 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
2827 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
2828 }
2829
2830 @ForceInline
2831 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
2832 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
2833 }
2834
2835 @ForceInline
2836 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
2837 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
2838 }
2839
2840 @IntrinsicCandidate
2841 public final short getAndSetShort(Object o, long offset, short newValue) {
2842 short v;
2843 do {
2844 v = getShortVolatile(o, offset);
2845 } while (!weakCompareAndSetShort(o, offset, v, newValue));
2846 return v;
2847 }
2848
2849 @ForceInline
2850 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
2851 short v;
2852 do {
2853 v = getShort(o, offset);
2854 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
2855 return v;
2856 }
2857
2858 @ForceInline
2859 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
2860 short v;
2861 do {
2862 v = getShortAcquire(o, offset);
2863 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
2864 return v;
2865 }
2866
2867 @ForceInline
2868 public final char getAndSetChar(Object o, long offset, char newValue) {
2869 return s2c(getAndSetShort(o, offset, c2s(newValue)));
2870 }
2871
2872 @ForceInline
2873 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
2874 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
2875 }
2876
2877 @ForceInline
2878 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
2879 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
2880 }
2881
2882 @ForceInline
2883 public final float getAndSetFloat(Object o, long offset, float newValue) {
2884 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
2885 return Float.intBitsToFloat(v);
2886 }
2887
2888 @ForceInline
2889 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
2890 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
2891 return Float.intBitsToFloat(v);
2892 }
2893
2894 @ForceInline
2895 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
2896 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
2897 return Float.intBitsToFloat(v);
2898 }
2899
2900 @ForceInline
2901 public final double getAndSetDouble(Object o, long offset, double newValue) {
2902 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
2903 return Double.longBitsToDouble(v);
2904 }
2905
2906 @ForceInline
2907 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
2908 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
2909 return Double.longBitsToDouble(v);
2910 }
2911
2912 @ForceInline
2913 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
2914 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
2915 return Double.longBitsToDouble(v);
2916 }
2917
2918
2919 // The following contain CAS-based Java implementations used on
2920 // platforms not supporting native instructions
2921
2922 @ForceInline
2923 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
2924 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
2925 }
2926
2927 @ForceInline
2928 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
2929 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
2930 }
2931
2932 @ForceInline
2933 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
2934 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
2935 }
2936
2937 @ForceInline
2938 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
2939 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
2940 }
2941
2942 @ForceInline
2943 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
2944 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
2945 }
2946
2947 @ForceInline
2948 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
2949 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
2950 }
2951
2952 @ForceInline
2953 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
2954 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
2955 }
2956
2957 @ForceInline
2958 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
2959 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
2960 }
2961
2962 @ForceInline
2963 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
2964 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
2965 }
2966
2967
2968 @ForceInline
2969 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
2970 byte current;
2971 do {
2972 current = getByteVolatile(o, offset);
2973 } while (!weakCompareAndSetByte(o, offset,
2974 current, (byte) (current | mask)));
2975 return current;
2976 }
2977
2978 @ForceInline
2979 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
2980 byte current;
2981 do {
2982 current = getByte(o, offset);
2983 } while (!weakCompareAndSetByteRelease(o, offset,
2984 current, (byte) (current | mask)));
2985 return current;
2986 }
2987
2988 @ForceInline
2989 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
2990 byte current;
2991 do {
2992 // Plain read, the value is a hint, the acquire CAS does the work
2993 current = getByte(o, offset);
2994 } while (!weakCompareAndSetByteAcquire(o, offset,
2995 current, (byte) (current | mask)));
2996 return current;
2997 }
2998
2999 @ForceInline
3000 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
3001 byte current;
3002 do {
3003 current = getByteVolatile(o, offset);
3004 } while (!weakCompareAndSetByte(o, offset,
3005 current, (byte) (current & mask)));
3006 return current;
3007 }
3008
3009 @ForceInline
3010 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
3011 byte current;
3012 do {
3013 current = getByte(o, offset);
3014 } while (!weakCompareAndSetByteRelease(o, offset,
3015 current, (byte) (current & mask)));
3016 return current;
3017 }
3018
3019 @ForceInline
3020 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
3021 byte current;
3022 do {
3023 // Plain read, the value is a hint, the acquire CAS does the work
3024 current = getByte(o, offset);
3025 } while (!weakCompareAndSetByteAcquire(o, offset,
3026 current, (byte) (current & mask)));
3027 return current;
3028 }
3029
3030 @ForceInline
3031 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
3032 byte current;
3033 do {
3034 current = getByteVolatile(o, offset);
3035 } while (!weakCompareAndSetByte(o, offset,
3036 current, (byte) (current ^ mask)));
3037 return current;
3038 }
3039
3040 @ForceInline
3041 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
3042 byte current;
3043 do {
3044 current = getByte(o, offset);
3045 } while (!weakCompareAndSetByteRelease(o, offset,
3046 current, (byte) (current ^ mask)));
3047 return current;
3048 }
3049
3050 @ForceInline
3051 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3052 byte current;
3053 do {
3054 // Plain read, the value is a hint, the acquire CAS does the work
3055 current = getByte(o, offset);
3056 } while (!weakCompareAndSetByteAcquire(o, offset,
3057 current, (byte) (current ^ mask)));
3058 return current;
3059 }
3060
3061
3062 @ForceInline
3063 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3064 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3065 }
3066
3067 @ForceInline
3068 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3069 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3070 }
3071
3072 @ForceInline
3073 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3074 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3075 }
3076
3077 @ForceInline
3078 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3079 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3080 }
3081
3082 @ForceInline
3083 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3084 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3085 }
3086
3087 @ForceInline
3088 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3089 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3090 }
3091
3092 @ForceInline
3093 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3094 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3095 }
3096
3097 @ForceInline
3098 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3099 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3100 }
3101
3102 @ForceInline
3103 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3104 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3105 }
3106
3107
3108 @ForceInline
3109 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3110 short current;
3111 do {
3112 current = getShortVolatile(o, offset);
3113 } while (!weakCompareAndSetShort(o, offset,
3114 current, (short) (current | mask)));
3115 return current;
3116 }
3117
3118 @ForceInline
3119 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3120 short current;
3121 do {
3122 current = getShort(o, offset);
3123 } while (!weakCompareAndSetShortRelease(o, offset,
3124 current, (short) (current | mask)));
3125 return current;
3126 }
3127
3128 @ForceInline
3129 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3130 short current;
3131 do {
3132 // Plain read, the value is a hint, the acquire CAS does the work
3133 current = getShort(o, offset);
3134 } while (!weakCompareAndSetShortAcquire(o, offset,
3135 current, (short) (current | mask)));
3136 return current;
3137 }
3138
3139 @ForceInline
3140 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3141 short current;
3142 do {
3143 current = getShortVolatile(o, offset);
3144 } while (!weakCompareAndSetShort(o, offset,
3145 current, (short) (current & mask)));
3146 return current;
3147 }
3148
3149 @ForceInline
3150 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3151 short current;
3152 do {
3153 current = getShort(o, offset);
3154 } while (!weakCompareAndSetShortRelease(o, offset,
3155 current, (short) (current & mask)));
3156 return current;
3157 }
3158
3159 @ForceInline
3160 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3161 short current;
3162 do {
3163 // Plain read, the value is a hint, the acquire CAS does the work
3164 current = getShort(o, offset);
3165 } while (!weakCompareAndSetShortAcquire(o, offset,
3166 current, (short) (current & mask)));
3167 return current;
3168 }
3169
3170 @ForceInline
3171 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3172 short current;
3173 do {
3174 current = getShortVolatile(o, offset);
3175 } while (!weakCompareAndSetShort(o, offset,
3176 current, (short) (current ^ mask)));
3177 return current;
3178 }
3179
3180 @ForceInline
3181 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3182 short current;
3183 do {
3184 current = getShort(o, offset);
3185 } while (!weakCompareAndSetShortRelease(o, offset,
3186 current, (short) (current ^ mask)));
3187 return current;
3188 }
3189
3190 @ForceInline
3191 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3192 short current;
3193 do {
3194 // Plain read, the value is a hint, the acquire CAS does the work
3195 current = getShort(o, offset);
3196 } while (!weakCompareAndSetShortAcquire(o, offset,
3197 current, (short) (current ^ mask)));
3198 return current;
3199 }
3200
3201
3202 @ForceInline
3203 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3204 int current;
3205 do {
3206 current = getIntVolatile(o, offset);
3207 } while (!weakCompareAndSetInt(o, offset,
3208 current, current | mask));
3209 return current;
3210 }
3211
3212 @ForceInline
3213 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3214 int current;
3215 do {
3216 current = getInt(o, offset);
3217 } while (!weakCompareAndSetIntRelease(o, offset,
3218 current, current | mask));
3219 return current;
3220 }
3221
3222 @ForceInline
3223 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3224 int current;
3225 do {
3226 // Plain read, the value is a hint, the acquire CAS does the work
3227 current = getInt(o, offset);
3228 } while (!weakCompareAndSetIntAcquire(o, offset,
3229 current, current | mask));
3230 return current;
3231 }
3232
3233 /**
3234 * Atomically replaces the current value of a field or array element within
3235 * the given object with the result of bitwise AND between the current value
3236 * and mask.
3237 *
3238 * @param o object/array to update the field/element in
3239 * @param offset field/element offset
3240 * @param mask the mask value
3241 * @return the previous value
3242 * @since 9
3243 */
3244 @ForceInline
3245 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3246 int current;
3247 do {
3248 current = getIntVolatile(o, offset);
3249 } while (!weakCompareAndSetInt(o, offset,
3250 current, current & mask));
3251 return current;
3252 }
3253
3254 @ForceInline
3255 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3256 int current;
3257 do {
3258 current = getInt(o, offset);
3259 } while (!weakCompareAndSetIntRelease(o, offset,
3260 current, current & mask));
3261 return current;
3262 }
3263
3264 @ForceInline
3265 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3266 int current;
3267 do {
3268 // Plain read, the value is a hint, the acquire CAS does the work
3269 current = getInt(o, offset);
3270 } while (!weakCompareAndSetIntAcquire(o, offset,
3271 current, current & mask));
3272 return current;
3273 }
3274
3275 @ForceInline
3276 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3277 int current;
3278 do {
3279 current = getIntVolatile(o, offset);
3280 } while (!weakCompareAndSetInt(o, offset,
3281 current, current ^ mask));
3282 return current;
3283 }
3284
3285 @ForceInline
3286 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3287 int current;
3288 do {
3289 current = getInt(o, offset);
3290 } while (!weakCompareAndSetIntRelease(o, offset,
3291 current, current ^ mask));
3292 return current;
3293 }
3294
3295 @ForceInline
3296 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3297 int current;
3298 do {
3299 // Plain read, the value is a hint, the acquire CAS does the work
3300 current = getInt(o, offset);
3301 } while (!weakCompareAndSetIntAcquire(o, offset,
3302 current, current ^ mask));
3303 return current;
3304 }
3305
3306
3307 @ForceInline
3308 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3309 long current;
3310 do {
3311 current = getLongVolatile(o, offset);
3312 } while (!weakCompareAndSetLong(o, offset,
3313 current, current | mask));
3314 return current;
3315 }
3316
3317 @ForceInline
3318 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3319 long current;
3320 do {
3321 current = getLong(o, offset);
3322 } while (!weakCompareAndSetLongRelease(o, offset,
3323 current, current | mask));
3324 return current;
3325 }
3326
3327 @ForceInline
3328 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3329 long current;
3330 do {
3331 // Plain read, the value is a hint, the acquire CAS does the work
3332 current = getLong(o, offset);
3333 } while (!weakCompareAndSetLongAcquire(o, offset,
3334 current, current | mask));
3335 return current;
3336 }
3337
3338 @ForceInline
3339 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3340 long current;
3341 do {
3342 current = getLongVolatile(o, offset);
3343 } while (!weakCompareAndSetLong(o, offset,
3344 current, current & mask));
3345 return current;
3346 }
3347
3348 @ForceInline
3349 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3350 long current;
3351 do {
3352 current = getLong(o, offset);
3353 } while (!weakCompareAndSetLongRelease(o, offset,
3354 current, current & mask));
3355 return current;
3356 }
3357
3358 @ForceInline
3359 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3360 long current;
3361 do {
3362 // Plain read, the value is a hint, the acquire CAS does the work
3363 current = getLong(o, offset);
3364 } while (!weakCompareAndSetLongAcquire(o, offset,
3365 current, current & mask));
3366 return current;
3367 }
3368
3369 @ForceInline
3370 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3371 long current;
3372 do {
3373 current = getLongVolatile(o, offset);
3374 } while (!weakCompareAndSetLong(o, offset,
3375 current, current ^ mask));
3376 return current;
3377 }
3378
3379 @ForceInline
3380 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3381 long current;
3382 do {
3383 current = getLong(o, offset);
3384 } while (!weakCompareAndSetLongRelease(o, offset,
3385 current, current ^ mask));
3386 return current;
3387 }
3388
3389 @ForceInline
3390 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3391 long current;
3392 do {
3393 // Plain read, the value is a hint, the acquire CAS does the work
3394 current = getLong(o, offset);
3395 } while (!weakCompareAndSetLongAcquire(o, offset,
3396 current, current ^ mask));
3397 return current;
3398 }
3399
3400
3401
3402 /**
3403 * Ensures that loads before the fence will not be reordered with loads and
3404 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3405 *
3406 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3407 * (an "acquire fence").
3408 *
3409 * Provides a LoadLoad barrier followed by a LoadStore barrier.
3410 *
3411 * @since 1.8
3412 */
3413 @IntrinsicCandidate
3414 public final void loadFence() {
3415 // If loadFence intrinsic is not available, fall back to full fence.
3416 fullFence();
3417 }
3418
3419 /**
3420 * Ensures that loads and stores before the fence will not be reordered with
3421 * stores after the fence; a "StoreStore plus LoadStore barrier".
3422 *
3423 * Corresponds to C11 atomic_thread_fence(memory_order_release)
3424 * (a "release fence").
3425 *
3426 * Provides a StoreStore barrier followed by a LoadStore barrier.
3427 *
3428 * @since 1.8
3429 */
3430 @IntrinsicCandidate
3431 public final void storeFence() {
3432 // If storeFence intrinsic is not available, fall back to full fence.
3433 fullFence();
3434 }
3435
3436 /**
3437 * Ensures that loads and stores before the fence will not be reordered
3438 * with loads and stores after the fence. Implies the effects of both
3439 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
3440 * barrier.
3441 *
3442 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
3443 * @since 1.8
3444 */
3445 @IntrinsicCandidate
3446 public native void fullFence();
3447
3448 /**
3449 * Ensures that loads before the fence will not be reordered with
3450 * loads after the fence.
3451 *
3452 * @implNote
3453 * This method is operationally equivalent to {@link #loadFence()}.
3454 *
3455 * @since 9
3456 */
3457 public final void loadLoadFence() {
3458 loadFence();
3459 }
3460
3461 /**
3462 * Ensures that stores before the fence will not be reordered with
3463 * stores after the fence.
3464 *
3465 * @since 9
3466 */
3467 @IntrinsicCandidate
3468 public final void storeStoreFence() {
3469 // If storeStoreFence intrinsic is not available, fall back to storeFence.
3470 storeFence();
3471 }
3472
3473 /**
3474 * Throws IllegalAccessError; for use by the VM for access control
3475 * error support.
3476 * @since 1.8
3477 */
3478 private static void throwIllegalAccessError() {
3479 throw new IllegalAccessError();
3480 }
3481
3482 /**
3483 * Throws NoSuchMethodError; for use by the VM for redefinition support.
3484 * @since 13
3485 */
3486 private static void throwNoSuchMethodError() {
3487 throw new NoSuchMethodError();
3488 }
3489
3490 /**
3491 * @return Returns true if the native byte ordering of this
3492 * platform is big-endian, false if it is little-endian.
3493 */
3494 public final boolean isBigEndian() { return BIG_ENDIAN; }
3495
3496 /**
3497 * @return Returns true if this platform is capable of performing
3498 * accesses at addresses which are not aligned for the type of the
3499 * primitive type being accessed, false otherwise.
3500 */
3501 public final boolean unalignedAccess() { return UNALIGNED_ACCESS; }
3502
3503 /**
3504 * Fetches a value at some byte offset into a given Java object.
3505 * More specifically, fetches a value within the given object
3506 * <code>o</code> at the given offset, or (if <code>o</code> is
3507 * null) from the memory address whose numerical value is the
3508 * given offset. <p>
3509 *
3510 * The specification of this method is the same as {@link
3511 * #getLong(Object, long)} except that the offset does not need to
3512 * have been obtained from {@link #objectFieldOffset} on the
3513 * {@link java.lang.reflect.Field} of some Java field. The value
3514 * in memory is raw data, and need not correspond to any Java
3515 * variable. Unless <code>o</code> is null, the value accessed
3516 * must be entirely within the allocated object. The endianness
3517 * of the value in memory is the endianness of the native platform.
3518 *
3519 * <p> The read will be atomic with respect to the largest power
3520 * of two that divides the GCD of the offset and the storage size.
3521 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
3522 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3523 * respectively. There are no other guarantees of atomicity.
3524 * <p>
3525 * 8-byte atomicity is only guaranteed on platforms on which
3526 * support atomic accesses to longs.
3527 *
3528 * @param o Java heap object in which the value resides, if any, else
3529 * null
3530 * @param offset The offset in bytes from the start of the object
3531 * @return the value fetched from the indicated object
3532 * @throws RuntimeException No defined exceptions are thrown, not even
3533 * {@link NullPointerException}
3534 * @since 9
3535 */
3536 @IntrinsicCandidate
3537 public final long getLongUnaligned(Object o, long offset) {
3538 if ((offset & 7) == 0) {
3539 return getLong(o, offset);
3540 } else if ((offset & 3) == 0) {
3541 return makeLong(getInt(o, offset),
3542 getInt(o, offset + 4));
3543 } else if ((offset & 1) == 0) {
3544 return makeLong(getShort(o, offset),
3545 getShort(o, offset + 2),
3546 getShort(o, offset + 4),
3547 getShort(o, offset + 6));
3548 } else {
3549 return makeLong(getByte(o, offset),
3550 getByte(o, offset + 1),
3551 getByte(o, offset + 2),
3552 getByte(o, offset + 3),
3553 getByte(o, offset + 4),
3554 getByte(o, offset + 5),
3555 getByte(o, offset + 6),
3556 getByte(o, offset + 7));
3557 }
3558 }
3559 /**
3560 * As {@link #getLongUnaligned(Object, long)} but with an
3561 * additional argument which specifies the endianness of the value
3562 * as stored in memory.
3563 *
3564 * @param o Java heap object in which the variable resides
3565 * @param offset The offset in bytes from the start of the object
3566 * @param bigEndian The endianness of the value
3567 * @return the value fetched from the indicated object
3568 * @since 9
3569 */
3570 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
3571 return convEndian(bigEndian, getLongUnaligned(o, offset));
3572 }
3573
3574 /** @see #getLongUnaligned(Object, long) */
3575 @IntrinsicCandidate
3576 public final int getIntUnaligned(Object o, long offset) {
3577 if ((offset & 3) == 0) {
3578 return getInt(o, offset);
3579 } else if ((offset & 1) == 0) {
3580 return makeInt(getShort(o, offset),
3581 getShort(o, offset + 2));
3582 } else {
3583 return makeInt(getByte(o, offset),
3584 getByte(o, offset + 1),
3585 getByte(o, offset + 2),
3586 getByte(o, offset + 3));
3587 }
3588 }
3589 /** @see #getLongUnaligned(Object, long, boolean) */
3590 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
3591 return convEndian(bigEndian, getIntUnaligned(o, offset));
3592 }
3593
3594 /** @see #getLongUnaligned(Object, long) */
3595 @IntrinsicCandidate
3596 public final short getShortUnaligned(Object o, long offset) {
3597 if ((offset & 1) == 0) {
3598 return getShort(o, offset);
3599 } else {
3600 return makeShort(getByte(o, offset),
3601 getByte(o, offset + 1));
3602 }
3603 }
3604 /** @see #getLongUnaligned(Object, long, boolean) */
3605 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
3606 return convEndian(bigEndian, getShortUnaligned(o, offset));
3607 }
3608
3609 /** @see #getLongUnaligned(Object, long) */
3610 @IntrinsicCandidate
3611 public final char getCharUnaligned(Object o, long offset) {
3612 if ((offset & 1) == 0) {
3613 return getChar(o, offset);
3614 } else {
3615 return (char)makeShort(getByte(o, offset),
3616 getByte(o, offset + 1));
3617 }
3618 }
3619
3620 /** @see #getLongUnaligned(Object, long, boolean) */
3621 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
3622 return convEndian(bigEndian, getCharUnaligned(o, offset));
3623 }
3624
3625 /**
3626 * Stores a value at some byte offset into a given Java object.
3627 * <p>
3628 * The specification of this method is the same as {@link
3629 * #getLong(Object, long)} except that the offset does not need to
3630 * have been obtained from {@link #objectFieldOffset} on the
3631 * {@link java.lang.reflect.Field} of some Java field. The value
3632 * in memory is raw data, and need not correspond to any Java
3633 * variable. The endianness of the value in memory is the
3634 * endianness of the native platform.
3635 * <p>
3636 * The write will be atomic with respect to the largest power of
3637 * two that divides the GCD of the offset and the storage size.
3638 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
3639 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3640 * respectively. There are no other guarantees of atomicity.
3641 * <p>
3642 * 8-byte atomicity is only guaranteed on platforms on which
3643 * support atomic accesses to longs.
3644 *
3645 * @param o Java heap object in which the value resides, if any, else
3646 * null
3647 * @param offset The offset in bytes from the start of the object
3648 * @param x the value to store
3649 * @throws RuntimeException No defined exceptions are thrown, not even
3650 * {@link NullPointerException}
3651 * @since 9
3652 */
3653 @IntrinsicCandidate
3654 public final void putLongUnaligned(Object o, long offset, long x) {
3655 if ((offset & 7) == 0) {
3656 putLong(o, offset, x);
3657 } else if ((offset & 3) == 0) {
3658 putLongParts(o, offset,
3659 (int)(x >> 0),
3660 (int)(x >>> 32));
3661 } else if ((offset & 1) == 0) {
3662 putLongParts(o, offset,
3663 (short)(x >>> 0),
3664 (short)(x >>> 16),
3665 (short)(x >>> 32),
3666 (short)(x >>> 48));
3667 } else {
3668 putLongParts(o, offset,
3669 (byte)(x >>> 0),
3670 (byte)(x >>> 8),
3671 (byte)(x >>> 16),
3672 (byte)(x >>> 24),
3673 (byte)(x >>> 32),
3674 (byte)(x >>> 40),
3675 (byte)(x >>> 48),
3676 (byte)(x >>> 56));
3677 }
3678 }
3679
3680 /**
3681 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
3682 * argument which specifies the endianness of the value as stored in memory.
3683 * @param o Java heap object in which the value resides
3684 * @param offset The offset in bytes from the start of the object
3685 * @param x the value to store
3686 * @param bigEndian The endianness of the value
3687 * @throws RuntimeException No defined exceptions are thrown, not even
3688 * {@link NullPointerException}
3689 * @since 9
3690 */
3691 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
3692 putLongUnaligned(o, offset, convEndian(bigEndian, x));
3693 }
3694
3695 /** @see #putLongUnaligned(Object, long, long) */
3696 @IntrinsicCandidate
3697 public final void putIntUnaligned(Object o, long offset, int x) {
3698 if ((offset & 3) == 0) {
3699 putInt(o, offset, x);
3700 } else if ((offset & 1) == 0) {
3701 putIntParts(o, offset,
3702 (short)(x >> 0),
3703 (short)(x >>> 16));
3704 } else {
3705 putIntParts(o, offset,
3706 (byte)(x >>> 0),
3707 (byte)(x >>> 8),
3708 (byte)(x >>> 16),
3709 (byte)(x >>> 24));
3710 }
3711 }
3712 /** @see #putLongUnaligned(Object, long, long, boolean) */
3713 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
3714 putIntUnaligned(o, offset, convEndian(bigEndian, x));
3715 }
3716
3717 /** @see #putLongUnaligned(Object, long, long) */
3718 @IntrinsicCandidate
3719 public final void putShortUnaligned(Object o, long offset, short x) {
3720 if ((offset & 1) == 0) {
3721 putShort(o, offset, x);
3722 } else {
3723 putShortParts(o, offset,
3724 (byte)(x >>> 0),
3725 (byte)(x >>> 8));
3726 }
3727 }
3728 /** @see #putLongUnaligned(Object, long, long, boolean) */
3729 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
3730 putShortUnaligned(o, offset, convEndian(bigEndian, x));
3731 }
3732
3733 /** @see #putLongUnaligned(Object, long, long) */
3734 @IntrinsicCandidate
3735 public final void putCharUnaligned(Object o, long offset, char x) {
3736 putShortUnaligned(o, offset, (short)x);
3737 }
3738 /** @see #putLongUnaligned(Object, long, long, boolean) */
3739 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
3740 putCharUnaligned(o, offset, convEndian(bigEndian, x));
3741 }
3742
3743 private static int pickPos(int top, int pos) { return BIG_ENDIAN ? top - pos : pos; }
3744
3745 // These methods construct integers from bytes. The byte ordering
3746 // is the native endianness of this platform.
3747 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3748 return ((toUnsignedLong(i0) << pickPos(56, 0))
3749 | (toUnsignedLong(i1) << pickPos(56, 8))
3750 | (toUnsignedLong(i2) << pickPos(56, 16))
3751 | (toUnsignedLong(i3) << pickPos(56, 24))
3752 | (toUnsignedLong(i4) << pickPos(56, 32))
3753 | (toUnsignedLong(i5) << pickPos(56, 40))
3754 | (toUnsignedLong(i6) << pickPos(56, 48))
3755 | (toUnsignedLong(i7) << pickPos(56, 56)));
3756 }
3757 private static long makeLong(short i0, short i1, short i2, short i3) {
3758 return ((toUnsignedLong(i0) << pickPos(48, 0))
3759 | (toUnsignedLong(i1) << pickPos(48, 16))
3760 | (toUnsignedLong(i2) << pickPos(48, 32))
3761 | (toUnsignedLong(i3) << pickPos(48, 48)));
3762 }
3763 private static long makeLong(int i0, int i1) {
3764 return (toUnsignedLong(i0) << pickPos(32, 0))
3765 | (toUnsignedLong(i1) << pickPos(32, 32));
3766 }
3767 private static int makeInt(short i0, short i1) {
3768 return (toUnsignedInt(i0) << pickPos(16, 0))
3769 | (toUnsignedInt(i1) << pickPos(16, 16));
3770 }
3771 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
3772 return ((toUnsignedInt(i0) << pickPos(24, 0))
3773 | (toUnsignedInt(i1) << pickPos(24, 8))
3774 | (toUnsignedInt(i2) << pickPos(24, 16))
3775 | (toUnsignedInt(i3) << pickPos(24, 24)));
3776 }
3777 private static short makeShort(byte i0, byte i1) {
3778 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
3779 | (toUnsignedInt(i1) << pickPos(8, 8)));
3780 }
3781
3782 private static byte pick(byte le, byte be) { return BIG_ENDIAN ? be : le; }
3783 private static short pick(short le, short be) { return BIG_ENDIAN ? be : le; }
3784 private static int pick(int le, int be) { return BIG_ENDIAN ? be : le; }
3785
3786 // These methods write integers to memory from smaller parts
3787 // provided by their caller. The ordering in which these parts
3788 // are written is the native endianness of this platform.
3789 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3790 putByte(o, offset + 0, pick(i0, i7));
3791 putByte(o, offset + 1, pick(i1, i6));
3792 putByte(o, offset + 2, pick(i2, i5));
3793 putByte(o, offset + 3, pick(i3, i4));
3794 putByte(o, offset + 4, pick(i4, i3));
3795 putByte(o, offset + 5, pick(i5, i2));
3796 putByte(o, offset + 6, pick(i6, i1));
3797 putByte(o, offset + 7, pick(i7, i0));
3798 }
3799 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
3800 putShort(o, offset + 0, pick(i0, i3));
3801 putShort(o, offset + 2, pick(i1, i2));
3802 putShort(o, offset + 4, pick(i2, i1));
3803 putShort(o, offset + 6, pick(i3, i0));
3804 }
3805 private void putLongParts(Object o, long offset, int i0, int i1) {
3806 putInt(o, offset + 0, pick(i0, i1));
3807 putInt(o, offset + 4, pick(i1, i0));
3808 }
3809 private void putIntParts(Object o, long offset, short i0, short i1) {
3810 putShort(o, offset + 0, pick(i0, i1));
3811 putShort(o, offset + 2, pick(i1, i0));
3812 }
3813 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
3814 putByte(o, offset + 0, pick(i0, i3));
3815 putByte(o, offset + 1, pick(i1, i2));
3816 putByte(o, offset + 2, pick(i2, i1));
3817 putByte(o, offset + 3, pick(i3, i0));
3818 }
3819 private void putShortParts(Object o, long offset, byte i0, byte i1) {
3820 putByte(o, offset + 0, pick(i0, i1));
3821 putByte(o, offset + 1, pick(i1, i0));
3822 }
3823
3824 // Zero-extend an integer
3825 private static int toUnsignedInt(byte n) { return n & 0xff; }
3826 private static int toUnsignedInt(short n) { return n & 0xffff; }
3827 private static long toUnsignedLong(byte n) { return n & 0xffl; }
3828 private static long toUnsignedLong(short n) { return n & 0xffffl; }
3829 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
3830
3831 // Maybe byte-reverse an integer
3832 private static char convEndian(boolean big, char n) { return big == BIG_ENDIAN ? n : Character.reverseBytes(n); }
3833 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
3834 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
3835 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
3836
3837
3838
3839 private native long allocateMemory0(long bytes);
3840 private native long reallocateMemory0(long address, long bytes);
3841 private native void freeMemory0(long address);
3842 @IntrinsicCandidate
3843 private native void setMemory0(Object o, long offset, long bytes, byte value);
3844 @IntrinsicCandidate
3845 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
3846 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
3847 private native long objectFieldOffset0(Field f);
3848 private native long objectFieldOffset1(Class<?> c, String name);
3849 private native long staticFieldOffset0(Field f);
3850 private native Object staticFieldBase0(Field f);
3851 private native boolean shouldBeInitialized0(Class<?> c);
3852 private native void ensureClassInitialized0(Class<?> c);
3853 private native int arrayBaseOffset0(Class<?> arrayClass); // public version returns long to promote correct arithmetic
3854 private native int arrayIndexScale0(Class<?> arrayClass);
3855 private native int getLoadAverage0(double[] loadavg, int nelems);
3856
3857
3858 /**
3859 * Invokes the given direct byte buffer's cleaner, if any.
3860 *
3861 * @param directBuffer a direct byte buffer
3862 * @throws NullPointerException if {@code directBuffer} is null
3863 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
3864 * or is a {@link java.nio.Buffer#slice slice}, or is a
3865 * {@link java.nio.Buffer#duplicate duplicate}
3866 */
3867 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
3868 if (!directBuffer.isDirect())
3869 throw new IllegalArgumentException("buffer is non-direct");
3870
3871 DirectBuffer db = (DirectBuffer) directBuffer;
3872 if (db.attachment() != null)
3873 throw new IllegalArgumentException("duplicate or slice");
3874
3875 Cleaner cleaner = db.cleaner();
3876 if (cleaner != null) {
3877 cleaner.clean();
3878 }
3879 }
3880 }