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.value.ValueClass;
30 import jdk.internal.vm.annotation.ForceInline;
31 import jdk.internal.vm.annotation.IntrinsicCandidate;
32 import sun.nio.ch.DirectBuffer;
33
34 import java.lang.reflect.Field;
35 import java.security.ProtectionDomain;
36
37 import static jdk.internal.misc.UnsafeConstants.*;
38
39 /**
40 * A collection of methods for performing low-level, unsafe operations.
41 * Although the class and all methods are public, use of this class is
42 * limited because only trusted code can obtain instances of it.
43 *
44 * <em>Note:</em> It is the responsibility of the caller to make sure
45 * arguments are checked before methods of this class are
46 * called. While some rudimentary checks are performed on the input,
47 * the checks are best effort and when performance is an overriding
48 * priority, as when methods of this class are optimized by the
49 * runtime compiler, some or all checks (if any) may be elided. Hence,
50 * the caller must not rely on the checks and corresponding
51 * exceptions!
52 *
53 * @author John R. Rose
54 * @see #getUnsafe
55 */
56
57 public final class Unsafe {
58
59 private static native void registerNatives();
60 static {
61 runtimeSetup();
62 }
63
64 // Called from JVM when loading an AOT cache
65 private static void runtimeSetup() {
66 registerNatives();
67 }
68
69 private Unsafe() {}
70
71 private static final Unsafe theUnsafe = new Unsafe();
72
73 /**
74 * Provides the caller with the capability of performing unsafe
75 * operations.
76 *
77 * <p>The returned {@code Unsafe} object should be carefully guarded
78 * by the caller, since it can be used to read and write data at arbitrary
79 * memory addresses. It must never be passed to untrusted code.
80 *
81 * <p>Most methods in this class are very low-level, and correspond to a
82 * small number of hardware instructions (on typical machines). Compilers
83 * are encouraged to optimize these methods accordingly.
84 *
85 * <p>Here is a suggested idiom for using unsafe operations:
86 *
87 * <pre> {@code
88 * class MyTrustedClass {
89 * private static final Unsafe unsafe = Unsafe.getUnsafe();
90 * ...
91 * private long myCountAddress = ...;
92 * public int getCount() { return unsafe.getByte(myCountAddress); }
93 * }}</pre>
94 *
95 * (It may assist compilers to make the local variable {@code final}.)
96 */
97 public static Unsafe getUnsafe() {
98 return theUnsafe;
99 }
100
101 //--- peek and poke operations
102 // (compilers should optimize these to memory ops)
103
104 // These work on object fields in the Java heap.
105 // They will not work on elements of packed arrays.
106
107 /**
108 * Fetches a value from a given Java variable.
109 * More specifically, fetches a field or array element within the given
110 * object {@code o} at the given offset, or (if {@code o} is null)
111 * from the memory address whose numerical value is the given offset.
112 * <p>
113 * The results are undefined unless one of the following cases is true:
114 * <ul>
115 * <li>The offset was obtained from {@link #objectFieldOffset} on
116 * the {@link java.lang.reflect.Field} of some Java field and the object
117 * referred to by {@code o} is of a class compatible with that
118 * field's class.
119 *
120 * <li>The offset and object reference {@code o} (either null or
121 * non-null) were both obtained via {@link #staticFieldOffset}
122 * and {@link #staticFieldBase} (respectively) from the
123 * reflective {@link Field} representation of some Java field.
124 *
125 * <li>The object referred to by {@code o} is an array, and the offset
126 * is an integer of the form {@code B+N*S}, where {@code N} is
127 * a valid index into the array, and {@code B} and {@code S} are
128 * the values obtained by {@link #arrayBaseOffset} and {@link
129 * #arrayIndexScale} (respectively) from the array's class. The value
130 * referred to is the {@code N}<em>th</em> element of the array.
131 *
132 * </ul>
133 * <p>
134 * If one of the above cases is true, the call references a specific Java
135 * variable (field or array element). However, the results are undefined
136 * if that variable is not in fact of the type returned by this method.
137 * <p>
138 * This method refers to a variable by means of two parameters, and so
139 * it provides (in effect) a <em>double-register</em> addressing mode
140 * for Java variables. When the object reference is null, this method
141 * uses its offset as an absolute address. This is similar in operation
142 * to methods such as {@link #getInt(long)}, which provide (in effect) a
143 * <em>single-register</em> addressing mode for non-Java variables.
144 * However, because Java variables may have a different layout in memory
145 * from non-Java variables, programmers should not assume that these
146 * two addressing modes are ever equivalent. Also, programmers should
147 * remember that offsets from the double-register addressing mode cannot
148 * be portably confused with longs used in the single-register addressing
149 * mode.
150 *
151 * @param o Java heap object in which the variable resides, if any, else
152 * null
153 * @param offset indication of where the variable resides in a Java heap
154 * object, if any, else a memory address locating the variable
155 * statically
156 * @return the value fetched from the indicated Java variable
157 * @throws RuntimeException No defined exceptions are thrown, not even
158 * {@link NullPointerException}
159 */
160 @IntrinsicCandidate
161 public native int getInt(Object o, long offset);
162
163 /**
164 * Stores a value into a given Java variable.
165 * <p>
166 * The first two parameters are interpreted exactly as with
167 * {@link #getInt(Object, long)} to refer to a specific
168 * Java variable (field or array element). The given value
169 * is stored into that variable.
170 * <p>
171 * The variable must be of the same type as the method
172 * parameter {@code x}.
173 *
174 * @param o Java heap object in which the variable resides, if any, else
175 * null
176 * @param offset indication of where the variable resides in a Java heap
177 * object, if any, else a memory address locating the variable
178 * statically
179 * @param x the value to store into the indicated Java variable
180 * @throws RuntimeException No defined exceptions are thrown, not even
181 * {@link NullPointerException}
182 */
183 @IntrinsicCandidate
184 public native void putInt(Object o, long offset, int x);
185
186
187 /**
188 * Returns true if the given field is flattened.
189 */
190 public boolean isFlatField(Field f) {
191 if (f == null) {
192 throw new NullPointerException();
193 }
194 return isFlatField0(f);
195 }
196
197 private native boolean isFlatField0(Object o);
198
199 /* Returns true if the given field has a null marker
200 * <p>
201 * Nullable flat fields are stored in a flattened representation
202 * and have an associated null marker to indicate if the the field value is
203 * null or the one stored with the flat representation
204 */
205
206 public boolean hasNullMarker(Field f) {
207 if (f == null) {
208 throw new NullPointerException();
209 }
210 return hasNullMarker0(f);
211 }
212
213 private native boolean hasNullMarker0(Object o);
214
215 /* Returns the offset of the null marker of the field,
216 * or -1 if the field doesn't have a null marker
217 */
218
219 public int nullMarkerOffset(Field f) {
220 if (f == null) {
221 throw new NullPointerException();
222 }
223 return nullMarkerOffset0(f);
224 }
225
226 private native int nullMarkerOffset0(Object o);
227
228 public static final int NON_FLAT_LAYOUT = 0;
229
230 /* Reports the kind of layout used for an element in the storage
231 * allocation of the given array. Do not expect to perform any logic
232 * or layout control with this value, it is just an opaque token
233 * used for performance reasons.
234 *
235 * A layout of 0 indicates this array is not flat.
236 */
237 public int arrayLayout(Object[] array) {
238 if (array == null) {
239 throw new NullPointerException();
240 }
241 return arrayLayout0(array);
242 }
243
244 private native int arrayLayout0(Object[] array);
245
246
247 /* Reports the kind of layout used for a given field in the storage
248 * allocation of its class. Do not expect to perform any logic
249 * or layout control with this value, it is just an opaque token
250 * used for performance reasons.
251 *
252 * A layout of 0 indicates this field is not flat.
253 */
254 public int fieldLayout(Field f) {
255 if (f == null) {
256 throw new NullPointerException();
257 }
258 return fieldLayout0(f);
259 }
260
261 private native int fieldLayout0(Object o);
262
263 public native Object[] newSpecialArray(Class<?> componentType,
264 int length, int layoutKind);
265
266 /**
267 * Fetches a reference value from a given Java variable.
268 * This method can return a reference to either an object or value
269 * or a null reference.
270 *
271 * @see #getInt(Object, long)
272 */
273 @IntrinsicCandidate
274 public native Object getReference(Object o, long offset);
275
276 /**
277 * Stores a reference value into a given Java variable.
278 * This method can store a reference to either an object or value
279 * or a null reference.
280 * <p>
281 * Unless the reference {@code x} being stored is either null
282 * or matches the field type, the results are undefined.
283 * If the reference {@code o} is non-null, card marks or
284 * other store barriers for that object (if the VM requires them)
285 * are updated.
286 * @see #putInt(Object, long, int)
287 */
288 @IntrinsicCandidate
289 public native void putReference(Object o, long offset, Object x);
290
291 /**
292 * Fetches a value of type {@code <V>} from a given Java variable.
293 * More specifically, fetches a field or array element within the given
294 * {@code o} object at the given offset, or (if {@code o} is null)
295 * from the memory address whose numerical value is the given offset.
296 *
297 * @param o Java heap object in which the variable resides, if any, else
298 * null
299 * @param offset indication of where the variable resides in a Java heap
300 * object, if any, else a memory address locating the variable
301 * statically
302 * @param valueType value type
303 * @param <V> the type of a value
304 * @return the value fetched from the indicated Java variable
305 * @throws RuntimeException No defined exceptions are thrown, not even
306 * {@link NullPointerException}
307 */
308 @IntrinsicCandidate
309 public native <V> V getValue(Object o, long offset, Class<?> valueType);
310
311 /**
312 * Fetches a value of type {@code <V>} from a given Java variable.
313 * More specifically, fetches a field or array element within the given
314 * {@code o} object at the given offset, or (if {@code o} is null)
315 * from the memory address whose numerical value is the given offset.
316 *
317 * @param o Java heap object in which the variable resides, if any, else
318 * null
319 * @param offset indication of where the variable resides in a Java heap
320 * object, if any, else a memory address locating the variable
321 * statically
322 * @param layoutKind opaque value used by the VM to know the layout
323 * the field or array element. This value must be retrieved with
324 * {@link #fieldLayout} or {@link #arrayLayout}.
325 * @param valueType value type
326 * @param <V> the type of a value
327 * @return the value fetched from the indicated Java variable
328 * @throws RuntimeException No defined exceptions are thrown, not even
329 * {@link NullPointerException}
330 */
331 @IntrinsicCandidate
332 public native <V> V getFlatValue(Object o, long offset, int layoutKind, Class<?> valueType);
333
334
335 /**
336 * Stores the given value into a given Java variable.
337 *
338 * Unless the reference {@code o} being stored is either null
339 * or matches the field type, the results are undefined.
340 *
341 * @param o Java heap object in which the variable resides, if any, else
342 * null
343 * @param offset indication of where the variable resides in a Java heap
344 * object, if any, else a memory address locating the variable
345 * statically
346 * @param valueType value type
347 * @param v the value to store into the indicated Java variable
348 * @param <V> the type of a value
349 * @throws RuntimeException No defined exceptions are thrown, not even
350 * {@link NullPointerException}
351 */
352 @IntrinsicCandidate
353 public native <V> void putValue(Object o, long offset, Class<?> valueType, V v);
354
355 /**
356 * Stores the given value into a given Java variable.
357 *
358 * Unless the reference {@code o} being stored is either null
359 * or matches the field type, the results are undefined.
360 *
361 * @param o Java heap object in which the variable resides, if any, else
362 * null
363 * @param offset indication of where the variable resides in a Java heap
364 * object, if any, else a memory address locating the variable
365 * statically
366 * @param layoutKind opaque value used by the VM to know the layout
367 * the field or array element. This value must be retrieved with
368 * {@link #fieldLayout} or {@link #arrayLayout}.
369 * @param valueType value type
370 * @param v the value to store into the indicated Java variable
371 * @param <V> the type of a value
372 * @throws RuntimeException No defined exceptions are thrown, not even
373 * {@link NullPointerException}
374 */
375 @IntrinsicCandidate
376 public native <V> void putFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, V v);
377
378 /**
379 * Returns an object instance with a private buffered value whose layout
380 * and contents is exactly the given value instance. The return object
381 * is in the larval state that can be updated using the unsafe put operation.
382 *
383 * @param value a value instance
384 * @param <V> the type of the given value instance
385 */
386 @IntrinsicCandidate
387 public native <V> V makePrivateBuffer(V value);
388
389 /**
390 * Exits the larval state and returns a value instance.
391 *
392 * @param value a value instance
393 * @param <V> the type of the given value instance
394 */
395 @IntrinsicCandidate
396 public native <V> V finishPrivateBuffer(V value);
397
398 /**
399 * Returns the header size of the given value type.
400 *
401 * @param valueType value type
402 * @return the header size of the value type
403 */
404 public native <V> long valueHeaderSize(Class<V> valueType);
405
406 /** @see #getInt(Object, long) */
407 @IntrinsicCandidate
408 public native boolean getBoolean(Object o, long offset);
409
410 /** @see #putInt(Object, long, int) */
411 @IntrinsicCandidate
412 public native void putBoolean(Object o, long offset, boolean x);
413
414 /** @see #getInt(Object, long) */
415 @IntrinsicCandidate
416 public native byte getByte(Object o, long offset);
417
418 /** @see #putInt(Object, long, int) */
419 @IntrinsicCandidate
420 public native void putByte(Object o, long offset, byte x);
421
422 /** @see #getInt(Object, long) */
423 @IntrinsicCandidate
424 public native short getShort(Object o, long offset);
425
426 /** @see #putInt(Object, long, int) */
427 @IntrinsicCandidate
428 public native void putShort(Object o, long offset, short x);
429
430 /** @see #getInt(Object, long) */
431 @IntrinsicCandidate
432 public native char getChar(Object o, long offset);
433
434 /** @see #putInt(Object, long, int) */
435 @IntrinsicCandidate
436 public native void putChar(Object o, long offset, char x);
437
438 /** @see #getInt(Object, long) */
439 @IntrinsicCandidate
440 public native long getLong(Object o, long offset);
441
442 /** @see #putInt(Object, long, int) */
443 @IntrinsicCandidate
444 public native void putLong(Object o, long offset, long x);
445
446 /** @see #getInt(Object, long) */
447 @IntrinsicCandidate
448 public native float getFloat(Object o, long offset);
449
450 /** @see #putInt(Object, long, int) */
451 @IntrinsicCandidate
452 public native void putFloat(Object o, long offset, float x);
453
454 /** @see #getInt(Object, long) */
455 @IntrinsicCandidate
456 public native double getDouble(Object o, long offset);
457
458 /** @see #putInt(Object, long, int) */
459 @IntrinsicCandidate
460 public native void putDouble(Object o, long offset, double x);
461
462 /**
463 * Fetches a native pointer from a given memory address. If the address is
464 * zero, or does not point into a block obtained from {@link
465 * #allocateMemory}, the results are undefined.
466 *
467 * <p>If the native pointer is less than 64 bits wide, it is extended as
468 * an unsigned number to a Java long. The pointer may be indexed by any
469 * given byte offset, simply by adding that offset (as a simple integer) to
470 * the long representing the pointer. The number of bytes actually read
471 * from the target address may be determined by consulting {@link
472 * #addressSize}.
473 *
474 * @see #allocateMemory
475 * @see #getInt(Object, long)
476 */
477 @ForceInline
478 public long getAddress(Object o, long offset) {
479 if (ADDRESS_SIZE == 4) {
480 return Integer.toUnsignedLong(getInt(o, offset));
481 } else {
482 return getLong(o, offset);
483 }
484 }
485
486 /**
487 * Stores a native pointer into a given memory address. If the address is
488 * zero, or does not point into a block obtained from {@link
489 * #allocateMemory}, the results are undefined.
490 *
491 * <p>The number of bytes actually written at the target address may be
492 * determined by consulting {@link #addressSize}.
493 *
494 * @see #allocateMemory
495 * @see #putInt(Object, long, int)
496 */
497 @ForceInline
498 public void putAddress(Object o, long offset, long x) {
499 if (ADDRESS_SIZE == 4) {
500 putInt(o, offset, (int)x);
501 } else {
502 putLong(o, offset, x);
503 }
504 }
505
506 // These read VM internal data.
507
508 /**
509 * Fetches an uncompressed reference value from a given native variable
510 * ignoring the VM's compressed references mode.
511 *
512 * @param address a memory address locating the variable
513 * @return the value fetched from the indicated native variable
514 */
515 public native Object getUncompressedObject(long address);
516
517 // These work on values in the C heap.
518
519 /**
520 * Fetches a value from a given memory address. If the address is zero, or
521 * does not point into a block obtained from {@link #allocateMemory}, the
522 * results are undefined.
523 *
524 * @see #allocateMemory
525 */
526 @ForceInline
527 public byte getByte(long address) {
528 return getByte(null, address);
529 }
530
531 /**
532 * Stores a value into a given memory address. If the address is zero, or
533 * does not point into a block obtained from {@link #allocateMemory}, the
534 * results are undefined.
535 *
536 * @see #getByte(long)
537 */
538 @ForceInline
539 public void putByte(long address, byte x) {
540 putByte(null, address, x);
541 }
542
543 /** @see #getByte(long) */
544 @ForceInline
545 public short getShort(long address) {
546 return getShort(null, address);
547 }
548
549 /** @see #putByte(long, byte) */
550 @ForceInline
551 public void putShort(long address, short x) {
552 putShort(null, address, x);
553 }
554
555 /** @see #getByte(long) */
556 @ForceInline
557 public char getChar(long address) {
558 return getChar(null, address);
559 }
560
561 /** @see #putByte(long, byte) */
562 @ForceInline
563 public void putChar(long address, char x) {
564 putChar(null, address, x);
565 }
566
567 /** @see #getByte(long) */
568 @ForceInline
569 public int getInt(long address) {
570 return getInt(null, address);
571 }
572
573 /** @see #putByte(long, byte) */
574 @ForceInline
575 public void putInt(long address, int x) {
576 putInt(null, address, x);
577 }
578
579 /** @see #getByte(long) */
580 @ForceInline
581 public long getLong(long address) {
582 return getLong(null, address);
583 }
584
585 /** @see #putByte(long, byte) */
586 @ForceInline
587 public void putLong(long address, long x) {
588 putLong(null, address, x);
589 }
590
591 /** @see #getByte(long) */
592 @ForceInline
593 public float getFloat(long address) {
594 return getFloat(null, address);
595 }
596
597 /** @see #putByte(long, byte) */
598 @ForceInline
599 public void putFloat(long address, float x) {
600 putFloat(null, address, x);
601 }
602
603 /** @see #getByte(long) */
604 @ForceInline
605 public double getDouble(long address) {
606 return getDouble(null, address);
607 }
608
609 /** @see #putByte(long, byte) */
610 @ForceInline
611 public void putDouble(long address, double x) {
612 putDouble(null, address, x);
613 }
614
615 /** @see #getAddress(Object, long) */
616 @ForceInline
617 public long getAddress(long address) {
618 return getAddress(null, address);
619 }
620
621 /** @see #putAddress(Object, long, long) */
622 @ForceInline
623 public void putAddress(long address, long x) {
624 putAddress(null, address, x);
625 }
626
627
628
629 //--- helper methods for validating various types of objects/values
630
631 /**
632 * Create an exception reflecting that some of the input was invalid
633 *
634 * <em>Note:</em> It is the responsibility of the caller to make
635 * sure arguments are checked before the methods are called. While
636 * some rudimentary checks are performed on the input, the checks
637 * are best effort and when performance is an overriding priority,
638 * as when methods of this class are optimized by the runtime
639 * compiler, some or all checks (if any) may be elided. Hence, the
640 * caller must not rely on the checks and corresponding
641 * exceptions!
642 *
643 * @return an exception object
644 */
645 private RuntimeException invalidInput() {
646 return new IllegalArgumentException();
647 }
648
649 /**
650 * Check if a value is 32-bit clean (32 MSB are all zero)
651 *
652 * @param value the 64-bit value to check
653 *
654 * @return true if the value is 32-bit clean
655 */
656 private boolean is32BitClean(long value) {
657 return value >>> 32 == 0;
658 }
659
660 /**
661 * Check the validity of a size (the equivalent of a size_t)
662 *
663 * @throws RuntimeException if the size is invalid
664 * (<em>Note:</em> after optimization, invalid inputs may
665 * go undetected, which will lead to unpredictable
666 * behavior)
667 */
668 private void checkSize(long size) {
669 if (ADDRESS_SIZE == 4) {
670 // Note: this will also check for negative sizes
671 if (!is32BitClean(size)) {
672 throw invalidInput();
673 }
674 } else if (size < 0) {
675 throw invalidInput();
676 }
677 }
678
679 /**
680 * Check the validity of a native address (the equivalent of void*)
681 *
682 * @throws RuntimeException if the address is invalid
683 * (<em>Note:</em> after optimization, invalid inputs may
684 * go undetected, which will lead to unpredictable
685 * behavior)
686 */
687 private void checkNativeAddress(long address) {
688 if (ADDRESS_SIZE == 4) {
689 // Accept both zero and sign extended pointers. A valid
690 // pointer will, after the +1 below, either have produced
691 // the value 0x0 or 0x1. Masking off the low bit allows
692 // for testing against 0.
693 if ((((address >> 32) + 1) & ~1) != 0) {
694 throw invalidInput();
695 }
696 }
697 }
698
699 /**
700 * Check the validity of an offset, relative to a base object
701 *
702 * @param o the base object
703 * @param offset the offset to check
704 *
705 * @throws RuntimeException if the size is invalid
706 * (<em>Note:</em> after optimization, invalid inputs may
707 * go undetected, which will lead to unpredictable
708 * behavior)
709 */
710 private void checkOffset(Object o, long offset) {
711 if (ADDRESS_SIZE == 4) {
712 // Note: this will also check for negative offsets
713 if (!is32BitClean(offset)) {
714 throw invalidInput();
715 }
716 } else if (offset < 0) {
717 throw invalidInput();
718 }
719 }
720
721 /**
722 * Check the validity of a double-register pointer
723 *
724 * Note: This code deliberately does *not* check for NPE for (at
725 * least) three reasons:
726 *
727 * 1) NPE is not just NULL/0 - there is a range of values all
728 * resulting in an NPE, which is not trivial to check for
729 *
730 * 2) It is the responsibility of the callers of Unsafe methods
731 * to verify the input, so throwing an exception here is not really
732 * useful - passing in a NULL pointer is a critical error and the
733 * must not expect an exception to be thrown anyway.
734 *
735 * 3) the actual operations will detect NULL pointers anyway by
736 * means of traps and signals (like SIGSEGV).
737 *
738 * @param o Java heap object, or null
739 * @param offset indication of where the variable resides in a Java heap
740 * object, if any, else a memory address locating the variable
741 * statically
742 *
743 * @throws RuntimeException if the pointer is invalid
744 * (<em>Note:</em> after optimization, invalid inputs may
745 * go undetected, which will lead to unpredictable
746 * behavior)
747 */
748 private void checkPointer(Object o, long offset) {
749 if (o == null) {
750 checkNativeAddress(offset);
751 } else {
752 checkOffset(o, offset);
753 }
754 }
755
756 /**
757 * Check if a type is a primitive array type
758 *
759 * @param c the type to check
760 *
761 * @return true if the type is a primitive array type
762 */
763 private void checkPrimitiveArray(Class<?> c) {
764 Class<?> componentType = c.getComponentType();
765 if (componentType == null || !componentType.isPrimitive()) {
766 throw invalidInput();
767 }
768 }
769
770 /**
771 * Check that a pointer is a valid primitive array type pointer
772 *
773 * Note: pointers off-heap are considered to be primitive arrays
774 *
775 * @throws RuntimeException if the pointer is invalid
776 * (<em>Note:</em> after optimization, invalid inputs may
777 * go undetected, which will lead to unpredictable
778 * behavior)
779 */
780 private void checkPrimitivePointer(Object o, long offset) {
781 checkPointer(o, offset);
782
783 if (o != null) {
784 // If on heap, it must be a primitive array
785 checkPrimitiveArray(o.getClass());
786 }
787 }
788
789
790 //--- wrappers for malloc, realloc, free:
791
792 /**
793 * Round up allocation size to a multiple of HeapWordSize.
794 */
795 private long alignToHeapWordSize(long bytes) {
796 if (bytes >= 0) {
797 return (bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1);
798 } else {
799 throw invalidInput();
800 }
801 }
802
803 /**
804 * Allocates a new block of native memory, of the given size in bytes. The
805 * contents of the memory are uninitialized; they will generally be
806 * garbage. The resulting native pointer will be zero if and only if the
807 * requested size is zero. The resulting native pointer will be aligned for
808 * all value types. Dispose of this memory by calling {@link #freeMemory}
809 * or resize it with {@link #reallocateMemory}.
810 *
811 * <em>Note:</em> It is the responsibility of the caller to make
812 * sure arguments are checked before the methods are called. While
813 * some rudimentary checks are performed on the input, the checks
814 * are best effort and when performance is an overriding priority,
815 * as when methods of this class are optimized by the runtime
816 * compiler, some or all checks (if any) may be elided. Hence, the
817 * caller must not rely on the checks and corresponding
818 * exceptions!
819 *
820 * @throws RuntimeException if the size is negative or too large
821 * for the native size_t type
822 *
823 * @throws OutOfMemoryError if the allocation is refused by the system
824 *
825 * @see #getByte(long)
826 * @see #putByte(long, byte)
827 */
828 public long allocateMemory(long bytes) {
829 bytes = alignToHeapWordSize(bytes);
830
831 allocateMemoryChecks(bytes);
832
833 if (bytes == 0) {
834 return 0;
835 }
836
837 long p = allocateMemory0(bytes);
838 if (p == 0) {
839 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
840 }
841
842 return p;
843 }
844
845 /**
846 * Validate the arguments to allocateMemory
847 *
848 * @throws RuntimeException if the arguments are invalid
849 * (<em>Note:</em> after optimization, invalid inputs may
850 * go undetected, which will lead to unpredictable
851 * behavior)
852 */
853 private void allocateMemoryChecks(long bytes) {
854 checkSize(bytes);
855 }
856
857 /**
858 * Resizes a new block of native memory, to the given size in bytes. The
859 * contents of the new block past the size of the old block are
860 * uninitialized; they will generally be garbage. The resulting native
861 * pointer will be zero if and only if the requested size is zero. The
862 * resulting native pointer will be aligned for all value types. Dispose
863 * of this memory by calling {@link #freeMemory}, or resize it with {@link
864 * #reallocateMemory}. The address passed to this method may be null, in
865 * which case an allocation will be performed.
866 *
867 * <em>Note:</em> It is the responsibility of the caller to make
868 * sure arguments are checked before the methods are called. While
869 * some rudimentary checks are performed on the input, the checks
870 * are best effort and when performance is an overriding priority,
871 * as when methods of this class are optimized by the runtime
872 * compiler, some or all checks (if any) may be elided. Hence, the
873 * caller must not rely on the checks and corresponding
874 * exceptions!
875 *
876 * @throws RuntimeException if the size is negative or too large
877 * for the native size_t type
878 *
879 * @throws OutOfMemoryError if the allocation is refused by the system
880 *
881 * @see #allocateMemory
882 */
883 public long reallocateMemory(long address, long bytes) {
884 bytes = alignToHeapWordSize(bytes);
885
886 reallocateMemoryChecks(address, bytes);
887
888 if (bytes == 0) {
889 freeMemory(address);
890 return 0;
891 }
892
893 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
894 if (p == 0) {
895 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
896 }
897
898 return p;
899 }
900
901 /**
902 * Validate the arguments to reallocateMemory
903 *
904 * @throws RuntimeException if the arguments are invalid
905 * (<em>Note:</em> after optimization, invalid inputs may
906 * go undetected, which will lead to unpredictable
907 * behavior)
908 */
909 private void reallocateMemoryChecks(long address, long bytes) {
910 checkPointer(null, address);
911 checkSize(bytes);
912 }
913
914 /**
915 * Sets all bytes in a given block of memory to a fixed value
916 * (usually zero).
917 *
918 * <p>This method determines a block's base address by means of two parameters,
919 * and so it provides (in effect) a <em>double-register</em> addressing mode,
920 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
921 * the offset supplies an absolute base address.
922 *
923 * <p>The stores are in coherent (atomic) units of a size determined
924 * by the address and length parameters. If the effective address and
925 * length are all even modulo 8, the stores take place in 'long' units.
926 * If the effective address and length are (resp.) even modulo 4 or 2,
927 * the stores take place in units of 'int' or 'short'.
928 *
929 * <em>Note:</em> It is the responsibility of the caller to make
930 * sure arguments are checked before the methods are called. While
931 * some rudimentary checks are performed on the input, the checks
932 * are best effort and when performance is an overriding priority,
933 * as when methods of this class are optimized by the runtime
934 * compiler, some or all checks (if any) may be elided. Hence, the
935 * caller must not rely on the checks and corresponding
936 * exceptions!
937 *
938 * @throws RuntimeException if any of the arguments is invalid
939 *
940 * @since 1.7
941 */
942 public void setMemory(Object o, long offset, long bytes, byte value) {
943 setMemoryChecks(o, offset, bytes, value);
944
945 if (bytes == 0) {
946 return;
947 }
948
949 setMemory0(o, offset, bytes, value);
950 }
951
952 /**
953 * Sets all bytes in a given block of memory to a fixed value
954 * (usually zero). This provides a <em>single-register</em> addressing mode,
955 * as discussed in {@link #getInt(Object,long)}.
956 *
957 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
958 */
959 public void setMemory(long address, long bytes, byte value) {
960 setMemory(null, address, bytes, value);
961 }
962
963 /**
964 * Validate the arguments to setMemory
965 *
966 * @throws RuntimeException if the arguments are invalid
967 * (<em>Note:</em> after optimization, invalid inputs may
968 * go undetected, which will lead to unpredictable
969 * behavior)
970 */
971 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
972 checkPrimitivePointer(o, offset);
973 checkSize(bytes);
974 }
975
976 /**
977 * Sets all bytes in a given block of memory to a copy of another
978 * block.
979 *
980 * <p>This method determines each block's base address by means of two parameters,
981 * and so it provides (in effect) a <em>double-register</em> addressing mode,
982 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
983 * the offset supplies an absolute base address.
984 *
985 * <p>The transfers are in coherent (atomic) units of a size determined
986 * by the address and length parameters. If the effective addresses and
987 * length are all even modulo 8, the transfer takes place in 'long' units.
988 * If the effective addresses and length are (resp.) even modulo 4 or 2,
989 * the transfer takes place in units of 'int' or 'short'.
990 *
991 * <em>Note:</em> It is the responsibility of the caller to make
992 * sure arguments are checked before the methods are called. While
993 * some rudimentary checks are performed on the input, the checks
994 * are best effort and when performance is an overriding priority,
995 * as when methods of this class are optimized by the runtime
996 * compiler, some or all checks (if any) may be elided. Hence, the
997 * caller must not rely on the checks and corresponding
998 * exceptions!
999 *
1000 * @throws RuntimeException if any of the arguments is invalid
1001 *
1002 * @since 1.7
1003 */
1004 public void copyMemory(Object srcBase, long srcOffset,
1005 Object destBase, long destOffset,
1006 long bytes) {
1007 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
1008
1009 if (bytes == 0) {
1010 return;
1011 }
1012
1013 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
1014 }
1015
1016 /**
1017 * Sets all bytes in a given block of memory to a copy of another
1018 * block. This provides a <em>single-register</em> addressing mode,
1019 * as discussed in {@link #getInt(Object,long)}.
1020 *
1021 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
1022 */
1023 public void copyMemory(long srcAddress, long destAddress, long bytes) {
1024 copyMemory(null, srcAddress, null, destAddress, bytes);
1025 }
1026
1027 /**
1028 * Validate the arguments to copyMemory
1029 *
1030 * @throws RuntimeException if any of the arguments is invalid
1031 * (<em>Note:</em> after optimization, invalid inputs may
1032 * go undetected, which will lead to unpredictable
1033 * behavior)
1034 */
1035 private void copyMemoryChecks(Object srcBase, long srcOffset,
1036 Object destBase, long destOffset,
1037 long bytes) {
1038 checkSize(bytes);
1039 checkPrimitivePointer(srcBase, srcOffset);
1040 checkPrimitivePointer(destBase, destOffset);
1041 }
1042
1043 /**
1044 * Copies all elements from one block of memory to another block,
1045 * *unconditionally* byte swapping the elements on the fly.
1046 *
1047 * <p>This method determines each block's base address by means of two parameters,
1048 * and so it provides (in effect) a <em>double-register</em> addressing mode,
1049 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
1050 * the offset supplies an absolute base address.
1051 *
1052 * <em>Note:</em> It is the responsibility of the caller to make
1053 * sure arguments are checked before the methods are called. While
1054 * some rudimentary checks are performed on the input, the checks
1055 * are best effort and when performance is an overriding priority,
1056 * as when methods of this class are optimized by the runtime
1057 * compiler, some or all checks (if any) may be elided. Hence, the
1058 * caller must not rely on the checks and corresponding
1059 * exceptions!
1060 *
1061 * @throws RuntimeException if any of the arguments is invalid
1062 *
1063 * @since 9
1064 */
1065 public void copySwapMemory(Object srcBase, long srcOffset,
1066 Object destBase, long destOffset,
1067 long bytes, long elemSize) {
1068 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
1069
1070 if (bytes == 0) {
1071 return;
1072 }
1073
1074 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
1075 }
1076
1077 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
1078 Object destBase, long destOffset,
1079 long bytes, long elemSize) {
1080 checkSize(bytes);
1081
1082 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
1083 throw invalidInput();
1084 }
1085 if (bytes % elemSize != 0) {
1086 throw invalidInput();
1087 }
1088
1089 checkPrimitivePointer(srcBase, srcOffset);
1090 checkPrimitivePointer(destBase, destOffset);
1091 }
1092
1093 /**
1094 * Copies all elements from one block of memory to another block, byte swapping the
1095 * elements on the fly.
1096 *
1097 * This provides a <em>single-register</em> addressing mode, as
1098 * discussed in {@link #getInt(Object,long)}.
1099 *
1100 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
1101 */
1102 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
1103 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
1104 }
1105
1106 /**
1107 * Disposes of a block of native memory, as obtained from {@link
1108 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
1109 * this method may be null, in which case no action is taken.
1110 *
1111 * <em>Note:</em> It is the responsibility of the caller to make
1112 * sure arguments are checked before the methods are called. While
1113 * some rudimentary checks are performed on the input, the checks
1114 * are best effort and when performance is an overriding priority,
1115 * as when methods of this class are optimized by the runtime
1116 * compiler, some or all checks (if any) may be elided. Hence, the
1117 * caller must not rely on the checks and corresponding
1118 * exceptions!
1119 *
1120 * @throws RuntimeException if any of the arguments is invalid
1121 *
1122 * @see #allocateMemory
1123 */
1124 public void freeMemory(long address) {
1125 freeMemoryChecks(address);
1126
1127 if (address == 0) {
1128 return;
1129 }
1130
1131 freeMemory0(address);
1132 }
1133
1134 /**
1135 * Validate the arguments to freeMemory
1136 *
1137 * @throws RuntimeException if the arguments are invalid
1138 * (<em>Note:</em> after optimization, invalid inputs may
1139 * go undetected, which will lead to unpredictable
1140 * behavior)
1141 */
1142 private void freeMemoryChecks(long address) {
1143 checkPointer(null, address);
1144 }
1145
1146 /**
1147 * Ensure writeback of a specified virtual memory address range
1148 * from cache to physical memory. All bytes in the address range
1149 * are guaranteed to have been written back to physical memory on
1150 * return from this call i.e. subsequently executed store
1151 * instructions are guaranteed not to be visible before the
1152 * writeback is completed.
1153 *
1154 * @param address
1155 * the lowest byte address that must be guaranteed written
1156 * back to memory. bytes at lower addresses may also be
1157 * written back.
1158 *
1159 * @param length
1160 * the length in bytes of the region starting at address
1161 * that must be guaranteed written back to memory.
1162 *
1163 * @throws RuntimeException if memory writeback is not supported
1164 * on the current hardware of if the arguments are invalid.
1165 * (<em>Note:</em> after optimization, invalid inputs may
1166 * go undetected, which will lead to unpredictable
1167 * behavior)
1168 *
1169 * @since 14
1170 */
1171
1172 public void writebackMemory(long address, long length) {
1173 checkWritebackEnabled();
1174 checkWritebackMemory(address, length);
1175
1176 // perform any required pre-writeback barrier
1177 writebackPreSync0();
1178
1179 // write back one cache line at a time
1180 long line = dataCacheLineAlignDown(address);
1181 long end = address + length;
1182 while (line < end) {
1183 writeback0(line);
1184 line += dataCacheLineFlushSize();
1185 }
1186
1187 // perform any required post-writeback barrier
1188 writebackPostSync0();
1189 }
1190
1191 /**
1192 * Validate the arguments to writebackMemory
1193 *
1194 * @throws RuntimeException if the arguments are invalid
1195 * (<em>Note:</em> after optimization, invalid inputs may
1196 * go undetected, which will lead to unpredictable
1197 * behavior)
1198 */
1199 private void checkWritebackMemory(long address, long length) {
1200 checkNativeAddress(address);
1201 checkSize(length);
1202 }
1203
1204 /**
1205 * Validate that the current hardware supports memory writeback.
1206 * (<em>Note:</em> this is a belt and braces check. Clients are
1207 * expected to test whether writeback is enabled by calling
1208 * ({@link isWritebackEnabled #isWritebackEnabled} and avoid
1209 * calling method {@link writeback #writeback} if it is disabled).
1210 *
1211 *
1212 * @throws RuntimeException if memory writeback is not supported
1213 */
1214 private void checkWritebackEnabled() {
1215 if (!isWritebackEnabled()) {
1216 throw new RuntimeException("writebackMemory not enabled!");
1217 }
1218 }
1219
1220 /**
1221 * force writeback of an individual cache line.
1222 *
1223 * @param address
1224 * the start address of the cache line to be written back
1225 */
1226 @IntrinsicCandidate
1227 private native void writeback0(long address);
1228
1229 /**
1230 * Serialize writeback operations relative to preceding memory writes.
1231 */
1232 @IntrinsicCandidate
1233 private native void writebackPreSync0();
1234
1235 /**
1236 * Serialize writeback operations relative to following memory writes.
1237 */
1238 @IntrinsicCandidate
1239 private native void writebackPostSync0();
1240
1241 //--- random queries
1242
1243 /**
1244 * This constant differs from all results that will ever be returned from
1245 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1246 * or {@link #arrayBaseOffset}.
1247 * <p>
1248 * The static type is @code long} to emphasize that long arithmetic should
1249 * always be used for offset calculations to avoid overflows.
1250 */
1251 public static final long INVALID_FIELD_OFFSET = -1;
1252
1253 /**
1254 * Reports the location of a given field in the storage allocation of its
1255 * class. Do not expect to perform any sort of arithmetic on this offset;
1256 * it is just a cookie which is passed to the unsafe heap memory accessors.
1257 *
1258 * <p>Any given field will always have the same offset and base, and no
1259 * two distinct fields of the same class will ever have the same offset
1260 * and base.
1261 *
1262 * <p>As of 1.4.1, offsets for fields are represented as long values,
1263 * although the Sun JVM does not use the most significant 32 bits.
1264 * However, JVM implementations which store static fields at absolute
1265 * addresses can use long offsets and null base pointers to express
1266 * the field locations in a form usable by {@link #getInt(Object,long)}.
1267 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1268 * must preserve all bits of static field offsets.
1269 * @see #getInt(Object, long)
1270 */
1271 public long objectFieldOffset(Field f) {
1272 if (f == null) {
1273 throw new NullPointerException();
1274 }
1275
1276 return objectFieldOffset0(f);
1277 }
1278
1279 /**
1280 * Reports the location of the field with a given name in the storage
1281 * allocation of its class.
1282 *
1283 * @throws NullPointerException if any parameter is {@code null}.
1284 * @throws InternalError if there is no field named {@code name} declared
1285 * in class {@code c}, i.e., if {@code c.getDeclaredField(name)}
1286 * would throw {@code java.lang.NoSuchFieldException}.
1287 *
1288 * @see #objectFieldOffset(Field)
1289 */
1290 public long objectFieldOffset(Class<?> c, String name) {
1291 if (c == null || name == null) {
1292 throw new NullPointerException();
1293 }
1294
1295 return objectFieldOffset1(c, name);
1296 }
1297
1298 /**
1299 * Reports the location of a given static field, in conjunction with {@link
1300 * #staticFieldBase}.
1301 * <p>Do not expect to perform any sort of arithmetic on this offset;
1302 * it is just a cookie which is passed to the unsafe heap memory accessors.
1303 *
1304 * <p>Any given field will always have the same offset, and no two distinct
1305 * fields of the same class will ever have the same offset.
1306 *
1307 * <p>As of 1.4.1, offsets for fields are represented as long values,
1308 * although the Sun JVM does not use the most significant 32 bits.
1309 * It is hard to imagine a JVM technology which needs more than
1310 * a few bits to encode an offset within a non-array object,
1311 * However, for consistency with other methods in this class,
1312 * this method reports its result as a long value.
1313 * @see #getInt(Object, long)
1314 */
1315 public long staticFieldOffset(Field f) {
1316 if (f == null) {
1317 throw new NullPointerException();
1318 }
1319
1320 return staticFieldOffset0(f);
1321 }
1322
1323 /**
1324 * Reports the location of a given static field, in conjunction with {@link
1325 * #staticFieldOffset}.
1326 * <p>Fetch the base "Object", if any, with which static fields of the
1327 * given class can be accessed via methods like {@link #getInt(Object,
1328 * long)}. This value may be null. This value may refer to an object
1329 * which is a "cookie", not guaranteed to be a real Object, and it should
1330 * not be used in any way except as argument to the get and put routines in
1331 * this class.
1332 */
1333 public Object staticFieldBase(Field f) {
1334 if (f == null) {
1335 throw new NullPointerException();
1336 }
1337
1338 return staticFieldBase0(f);
1339 }
1340
1341 /**
1342 * Detects if the given class may need to be initialized. This is often
1343 * needed in conjunction with obtaining the static field base of a
1344 * class.
1345 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1346 */
1347 public boolean shouldBeInitialized(Class<?> c) {
1348 if (c == null) {
1349 throw new NullPointerException();
1350 }
1351
1352 return shouldBeInitialized0(c);
1353 }
1354
1355 /**
1356 * Ensures the given class has been initialized (see JVMS-5.5 for details).
1357 * This is often needed in conjunction with obtaining the static field base
1358 * of a class.
1359 *
1360 * The call returns when either class {@code c} is fully initialized or
1361 * class {@code c} is being initialized and the call is performed from
1362 * the initializing thread. In the latter case a subsequent call to
1363 * {@link #shouldBeInitialized} will return {@code true}.
1364 */
1365 public void ensureClassInitialized(Class<?> c) {
1366 if (c == null) {
1367 throw new NullPointerException();
1368 }
1369
1370 ensureClassInitialized0(c);
1371 }
1372
1373 /**
1374 * The reading or writing of strict static fields may require
1375 * special processing. Notify the VM that such an event is about
1376 * to happen. The VM may respond by throwing an exception, in the
1377 * case of a read of an uninitialized field. If the VM allows the
1378 * method to return normally, no further calls are needed, with
1379 * the same arguments.
1380 */
1381 public void notifyStrictStaticAccess(Class<?> c, long staticFieldOffset, boolean writing) {
1382 if (c == null) {
1383 throw new NullPointerException();
1384 }
1385 notifyStrictStaticAccess0(c, staticFieldOffset, writing);
1386 }
1387
1388 /**
1389 * Reports the offset of the first element in the storage allocation of a
1390 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1391 * for the same class, you may use that scale factor, together with this
1392 * base offset, to form new offsets to access elements of arrays of the
1393 * given class.
1394 * <p>
1395 * The return value is in the range of a {@code int}. The return type is
1396 * {@code long} to emphasize that long arithmetic should always be used
1397 * for offset calculations to avoid overflows.
1398 *
1399 * @see #getInt(Object, long)
1400 * @see #putInt(Object, long, int)
1401 */
1402 public long arrayBaseOffset(Class<?> arrayClass) {
1403 if (arrayClass == null) {
1404 throw new NullPointerException();
1405 }
1406
1407 return arrayBaseOffset0(arrayClass);
1408 }
1409
1410 public long arrayBaseOffset(Object[] array) {
1411 if (array == null) {
1412 throw new NullPointerException();
1413 }
1414
1415 return arrayBaseOffset1(array);
1416 }
1417
1418 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1419 public static final long ARRAY_BOOLEAN_BASE_OFFSET
1420 = theUnsafe.arrayBaseOffset(boolean[].class);
1421
1422 /** The value of {@code arrayBaseOffset(byte[].class)} */
1423 public static final long ARRAY_BYTE_BASE_OFFSET
1424 = theUnsafe.arrayBaseOffset(byte[].class);
1425
1426 /** The value of {@code arrayBaseOffset(short[].class)} */
1427 public static final long ARRAY_SHORT_BASE_OFFSET
1428 = theUnsafe.arrayBaseOffset(short[].class);
1429
1430 /** The value of {@code arrayBaseOffset(char[].class)} */
1431 public static final long ARRAY_CHAR_BASE_OFFSET
1432 = theUnsafe.arrayBaseOffset(char[].class);
1433
1434 /** The value of {@code arrayBaseOffset(int[].class)} */
1435 public static final long ARRAY_INT_BASE_OFFSET
1436 = theUnsafe.arrayBaseOffset(int[].class);
1437
1438 /** The value of {@code arrayBaseOffset(long[].class)} */
1439 public static final long ARRAY_LONG_BASE_OFFSET
1440 = theUnsafe.arrayBaseOffset(long[].class);
1441
1442 /** The value of {@code arrayBaseOffset(float[].class)} */
1443 public static final long ARRAY_FLOAT_BASE_OFFSET
1444 = theUnsafe.arrayBaseOffset(float[].class);
1445
1446 /** The value of {@code arrayBaseOffset(double[].class)} */
1447 public static final long ARRAY_DOUBLE_BASE_OFFSET
1448 = theUnsafe.arrayBaseOffset(double[].class);
1449
1450 /** The value of {@code arrayBaseOffset(Object[].class)} */
1451 public static final long ARRAY_OBJECT_BASE_OFFSET
1452 = theUnsafe.arrayBaseOffset(Object[].class);
1453
1454 /**
1455 * Reports the scale factor for addressing elements in the storage
1456 * allocation of a given array class. However, arrays of "narrow" types
1457 * will generally not work properly with accessors like {@link
1458 * #getByte(Object, long)}, so the scale factor for such classes is reported
1459 * as zero.
1460 * <p>
1461 * The computation of the actual memory offset should always use {@code
1462 * long} arithmetic to avoid overflows.
1463 *
1464 * @see #arrayBaseOffset
1465 * @see #getInt(Object, long)
1466 * @see #putInt(Object, long, int)
1467 */
1468 public int arrayIndexScale(Class<?> arrayClass) {
1469 if (arrayClass == null) {
1470 throw new NullPointerException();
1471 }
1472
1473 return arrayIndexScale0(arrayClass);
1474 }
1475
1476 public int arrayIndexScale(Object[] array) {
1477 if (array == null) {
1478 throw new NullPointerException();
1479 }
1480
1481 return arrayIndexScale1(array);
1482 }
1483
1484 /**
1485 * Return the size of the object in the heap.
1486 * @param o an object
1487 * @return the objects's size
1488 * @since Valhalla
1489 */
1490 public long getObjectSize(Object o) {
1491 if (o == null)
1492 throw new NullPointerException();
1493 return getObjectSize0(o);
1494 }
1495
1496 /** The value of {@code arrayIndexScale(boolean[].class)} */
1497 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1498 = theUnsafe.arrayIndexScale(boolean[].class);
1499
1500 /** The value of {@code arrayIndexScale(byte[].class)} */
1501 public static final int ARRAY_BYTE_INDEX_SCALE
1502 = theUnsafe.arrayIndexScale(byte[].class);
1503
1504 /** The value of {@code arrayIndexScale(short[].class)} */
1505 public static final int ARRAY_SHORT_INDEX_SCALE
1506 = theUnsafe.arrayIndexScale(short[].class);
1507
1508 /** The value of {@code arrayIndexScale(char[].class)} */
1509 public static final int ARRAY_CHAR_INDEX_SCALE
1510 = theUnsafe.arrayIndexScale(char[].class);
1511
1512 /** The value of {@code arrayIndexScale(int[].class)} */
1513 public static final int ARRAY_INT_INDEX_SCALE
1514 = theUnsafe.arrayIndexScale(int[].class);
1515
1516 /** The value of {@code arrayIndexScale(long[].class)} */
1517 public static final int ARRAY_LONG_INDEX_SCALE
1518 = theUnsafe.arrayIndexScale(long[].class);
1519
1520 /** The value of {@code arrayIndexScale(float[].class)} */
1521 public static final int ARRAY_FLOAT_INDEX_SCALE
1522 = theUnsafe.arrayIndexScale(float[].class);
1523
1524 /** The value of {@code arrayIndexScale(double[].class)} */
1525 public static final int ARRAY_DOUBLE_INDEX_SCALE
1526 = theUnsafe.arrayIndexScale(double[].class);
1527
1528 /** The value of {@code arrayIndexScale(Object[].class)} */
1529 public static final int ARRAY_OBJECT_INDEX_SCALE
1530 = theUnsafe.arrayIndexScale(Object[].class);
1531
1532 /**
1533 * Reports the size in bytes of a native pointer, as stored via {@link
1534 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1535 * other primitive types (as stored in native memory blocks) is determined
1536 * fully by their information content.
1537 */
1538 public int addressSize() {
1539 return ADDRESS_SIZE;
1540 }
1541
1542 /** The value of {@code addressSize()} */
1543 public static final int ADDRESS_SIZE = ADDRESS_SIZE0;
1544
1545 /**
1546 * Reports the size in bytes of a native memory page (whatever that is).
1547 * This value will always be a power of two.
1548 */
1549 public int pageSize() { return PAGE_SIZE; }
1550
1551 /**
1552 * Reports the size in bytes of a data cache line written back by
1553 * the hardware cache line flush operation available to the JVM or
1554 * 0 if data cache line flushing is not enabled.
1555 */
1556 public int dataCacheLineFlushSize() { return DATA_CACHE_LINE_FLUSH_SIZE; }
1557
1558 /**
1559 * Rounds down address to a data cache line boundary as
1560 * determined by {@link #dataCacheLineFlushSize}
1561 * @return the rounded down address
1562 */
1563 public long dataCacheLineAlignDown(long address) {
1564 return (address & ~(DATA_CACHE_LINE_FLUSH_SIZE - 1));
1565 }
1566
1567 /**
1568 * Returns true if data cache line writeback
1569 */
1570 public static boolean isWritebackEnabled() { return DATA_CACHE_LINE_FLUSH_SIZE != 0; }
1571
1572 //--- random trusted operations from JNI:
1573
1574 /**
1575 * Tells the VM to define a class, without security checks. By default, the
1576 * class loader and protection domain come from the caller's class.
1577 */
1578 public Class<?> defineClass(String name, byte[] b, int off, int len,
1579 ClassLoader loader,
1580 ProtectionDomain protectionDomain) {
1581 if (b == null) {
1582 throw new NullPointerException();
1583 }
1584 if (len < 0) {
1585 throw new ArrayIndexOutOfBoundsException();
1586 }
1587
1588 return defineClass0(name, b, off, len, loader, protectionDomain);
1589 }
1590
1591 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1592 ClassLoader loader,
1593 ProtectionDomain protectionDomain);
1594
1595 /**
1596 * Allocates an instance but does not run any constructor.
1597 * Initializes the class if it has not yet been.
1598 */
1599 @IntrinsicCandidate
1600 public native Object allocateInstance(Class<?> cls)
1601 throws InstantiationException;
1602
1603 /**
1604 * Allocates an array of a given type, but does not do zeroing.
1605 * <p>
1606 * This method should only be used in the very rare cases where a high-performance code
1607 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1608 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1609 * <p>
1610 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1611 * before allowing untrusted code, or code in other threads, to observe the reference
1612 * to the newly allocated array. In addition, the publication of the array reference must be
1613 * safe according to the Java Memory Model requirements.
1614 * <p>
1615 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1616 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1617 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1618 * or issuing a {@link #storeFence} before publishing the reference.
1619 * <p>
1620 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1621 * elements that could break heap integrity.
1622 *
1623 * @param componentType array component type to allocate
1624 * @param length array size to allocate
1625 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1626 * or the length is negative
1627 */
1628 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1629 if (componentType == null) {
1630 throw new IllegalArgumentException("Component type is null");
1631 }
1632 if (!componentType.isPrimitive()) {
1633 throw new IllegalArgumentException("Component type is not primitive");
1634 }
1635 if (length < 0) {
1636 throw new IllegalArgumentException("Negative length");
1637 }
1638 return allocateUninitializedArray0(componentType, length);
1639 }
1640
1641 @IntrinsicCandidate
1642 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1643 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1644 // return the zeroed arrays.
1645 if (componentType == byte.class) return new byte[length];
1646 if (componentType == boolean.class) return new boolean[length];
1647 if (componentType == short.class) return new short[length];
1648 if (componentType == char.class) return new char[length];
1649 if (componentType == int.class) return new int[length];
1650 if (componentType == float.class) return new float[length];
1651 if (componentType == long.class) return new long[length];
1652 if (componentType == double.class) return new double[length];
1653 return null;
1654 }
1655
1656 /** Throws the exception without telling the verifier. */
1657 public native void throwException(Throwable ee);
1658
1659 /**
1660 * Atomically updates Java variable to {@code x} if it is currently
1661 * holding {@code expected}.
1662 *
1663 * <p>This operation has memory semantics of a {@code volatile} read
1664 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1665 *
1666 * @return {@code true} if successful
1667 */
1668 @IntrinsicCandidate
1669 public final native boolean compareAndSetReference(Object o, long offset,
1670 Object expected,
1671 Object x);
1672
1673 private final boolean isValueObject(Object o) {
1674 return o != null && o.getClass().isValue();
1675 }
1676
1677 /*
1678 * For value type, CAS should do substitutability test as opposed
1679 * to two pointers comparison.
1680 */
1681 @ForceInline
1682 public final <V> boolean compareAndSetReference(Object o, long offset,
1683 Class<?> type,
1684 V expected,
1685 V x) {
1686 if (type.isValue() || isValueObject(expected)) {
1687 while (true) {
1688 Object witness = getReferenceVolatile(o, offset);
1689 if (witness != expected) {
1690 return false;
1691 }
1692 if (compareAndSetReference(o, offset, witness, x)) {
1693 return true;
1694 }
1695 }
1696 } else {
1697 return compareAndSetReference(o, offset, expected, x);
1698 }
1699 }
1700
1701 @ForceInline
1702 public final <V> boolean compareAndSetFlatValue(Object o, long offset,
1703 int layout,
1704 Class<?> valueType,
1705 V expected,
1706 V x) {
1707 while (true) {
1708 Object witness = getFlatValueVolatile(o, offset, layout, valueType);
1709 if (witness != expected) {
1710 return false;
1711 }
1712 if (compareAndSetFlatValueAsBytes(o, offset, layout, valueType, witness, x)) {
1713 return true;
1714 }
1715 }
1716 }
1717
1718 @IntrinsicCandidate
1719 public final native Object compareAndExchangeReference(Object o, long offset,
1720 Object expected,
1721 Object x);
1722
1723 @ForceInline
1724 public final <V> Object compareAndExchangeReference(Object o, long offset,
1725 Class<?> valueType,
1726 V expected,
1727 V x) {
1728 if (valueType.isValue() || isValueObject(expected)) {
1729 while (true) {
1730 Object witness = getReferenceVolatile(o, offset);
1731 if (witness != expected) {
1732 return witness;
1733 }
1734 if (compareAndSetReference(o, offset, witness, x)) {
1735 return witness;
1736 }
1737 }
1738 } else {
1739 return compareAndExchangeReference(o, offset, expected, x);
1740 }
1741 }
1742
1743 @ForceInline
1744 public final <V> Object compareAndExchangeFlatValue(Object o, long offset,
1745 int layout,
1746 Class<?> valueType,
1747 V expected,
1748 V x) {
1749 while (true) {
1750 Object witness = getFlatValueVolatile(o, offset, layout, valueType);
1751 if (witness != expected) {
1752 return witness;
1753 }
1754 if (compareAndSetFlatValueAsBytes(o, offset, layout, valueType, witness, x)) {
1755 return witness;
1756 }
1757 }
1758 }
1759
1760 @IntrinsicCandidate
1761 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1762 Object expected,
1763 Object x) {
1764 return compareAndExchangeReference(o, offset, expected, x);
1765 }
1766
1767 public final <V> Object compareAndExchangeReferenceAcquire(Object o, long offset,
1768 Class<?> valueType,
1769 V expected,
1770 V x) {
1771 return compareAndExchangeReference(o, offset, valueType, expected, x);
1772 }
1773
1774 @ForceInline
1775 public final <V> Object compareAndExchangeFlatValueAcquire(Object o, long offset,
1776 int layout,
1777 Class<?> valueType,
1778 V expected,
1779 V x) {
1780 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1781 }
1782
1783 @IntrinsicCandidate
1784 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1785 Object expected,
1786 Object x) {
1787 return compareAndExchangeReference(o, offset, expected, x);
1788 }
1789
1790 public final <V> Object compareAndExchangeReferenceRelease(Object o, long offset,
1791 Class<?> valueType,
1792 V expected,
1793 V x) {
1794 return compareAndExchangeReference(o, offset, valueType, expected, x);
1795 }
1796
1797 @ForceInline
1798 public final <V> Object compareAndExchangeFlatValueRelease(Object o, long offset,
1799 int layout,
1800 Class<?> valueType,
1801 V expected,
1802 V x) {
1803 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1804 }
1805
1806 @IntrinsicCandidate
1807 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1808 Object expected,
1809 Object x) {
1810 return compareAndSetReference(o, offset, expected, x);
1811 }
1812
1813 public final <V> boolean weakCompareAndSetReferencePlain(Object o, long offset,
1814 Class<?> valueType,
1815 V expected,
1816 V x) {
1817 if (valueType.isValue() || isValueObject(expected)) {
1818 return compareAndSetReference(o, offset, valueType, expected, x);
1819 } else {
1820 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1821 }
1822 }
1823
1824 @ForceInline
1825 public final <V> boolean weakCompareAndSetFlatValuePlain(Object o, long offset,
1826 int layout,
1827 Class<?> valueType,
1828 V expected,
1829 V x) {
1830 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1831 }
1832
1833 @IntrinsicCandidate
1834 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1835 Object expected,
1836 Object x) {
1837 return compareAndSetReference(o, offset, expected, x);
1838 }
1839
1840 public final <V> boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1841 Class<?> valueType,
1842 V expected,
1843 V x) {
1844 if (valueType.isValue() || isValueObject(expected)) {
1845 return compareAndSetReference(o, offset, valueType, expected, x);
1846 } else {
1847 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1848 }
1849 }
1850
1851 @ForceInline
1852 public final <V> boolean weakCompareAndSetFlatValueAcquire(Object o, long offset,
1853 int layout,
1854 Class<?> valueType,
1855 V expected,
1856 V x) {
1857 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1858 }
1859
1860 @IntrinsicCandidate
1861 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1862 Object expected,
1863 Object x) {
1864 return compareAndSetReference(o, offset, expected, x);
1865 }
1866
1867 public final <V> boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1868 Class<?> valueType,
1869 V expected,
1870 V x) {
1871 if (valueType.isValue() || isValueObject(expected)) {
1872 return compareAndSetReference(o, offset, valueType, expected, x);
1873 } else {
1874 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1875 }
1876 }
1877
1878 @ForceInline
1879 public final <V> boolean weakCompareAndSetFlatValueRelease(Object o, long offset,
1880 int layout,
1881 Class<?> valueType,
1882 V expected,
1883 V x) {
1884 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1885 }
1886
1887 @IntrinsicCandidate
1888 public final boolean weakCompareAndSetReference(Object o, long offset,
1889 Object expected,
1890 Object x) {
1891 return compareAndSetReference(o, offset, expected, x);
1892 }
1893
1894 public final <V> boolean weakCompareAndSetReference(Object o, long offset,
1895 Class<?> valueType,
1896 V expected,
1897 V x) {
1898 if (valueType.isValue() || isValueObject(expected)) {
1899 return compareAndSetReference(o, offset, valueType, expected, x);
1900 } else {
1901 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1902 }
1903 }
1904
1905 @ForceInline
1906 public final <V> boolean weakCompareAndSetFlatValue(Object o, long offset,
1907 int layout,
1908 Class<?> valueType,
1909 V expected,
1910 V x) {
1911 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1912 }
1913
1914 /**
1915 * Atomically updates Java variable to {@code x} if it is currently
1916 * holding {@code expected}.
1917 *
1918 * <p>This operation has memory semantics of a {@code volatile} read
1919 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1920 *
1921 * @return {@code true} if successful
1922 */
1923 @IntrinsicCandidate
1924 public final native boolean compareAndSetInt(Object o, long offset,
1925 int expected,
1926 int x);
1927
1928 @IntrinsicCandidate
1929 public final native int compareAndExchangeInt(Object o, long offset,
1930 int expected,
1931 int x);
1932
1933 @IntrinsicCandidate
1934 public final int compareAndExchangeIntAcquire(Object o, long offset,
1935 int expected,
1936 int x) {
1937 return compareAndExchangeInt(o, offset, expected, x);
1938 }
1939
1940 @IntrinsicCandidate
1941 public final int compareAndExchangeIntRelease(Object o, long offset,
1942 int expected,
1943 int x) {
1944 return compareAndExchangeInt(o, offset, expected, x);
1945 }
1946
1947 @IntrinsicCandidate
1948 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1949 int expected,
1950 int x) {
1951 return compareAndSetInt(o, offset, expected, x);
1952 }
1953
1954 @IntrinsicCandidate
1955 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1956 int expected,
1957 int x) {
1958 return compareAndSetInt(o, offset, expected, x);
1959 }
1960
1961 @IntrinsicCandidate
1962 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1963 int expected,
1964 int x) {
1965 return compareAndSetInt(o, offset, expected, x);
1966 }
1967
1968 @IntrinsicCandidate
1969 public final boolean weakCompareAndSetInt(Object o, long offset,
1970 int expected,
1971 int x) {
1972 return compareAndSetInt(o, offset, expected, x);
1973 }
1974
1975 @IntrinsicCandidate
1976 public final byte compareAndExchangeByte(Object o, long offset,
1977 byte expected,
1978 byte x) {
1979 long wordOffset = offset & ~3;
1980 int shift = (int) (offset & 3) << 3;
1981 if (BIG_ENDIAN) {
1982 shift = 24 - shift;
1983 }
1984 int mask = 0xFF << shift;
1985 int maskedExpected = (expected & 0xFF) << shift;
1986 int maskedX = (x & 0xFF) << shift;
1987 int fullWord;
1988 do {
1989 fullWord = getIntVolatile(o, wordOffset);
1990 if ((fullWord & mask) != maskedExpected)
1991 return (byte) ((fullWord & mask) >> shift);
1992 } while (!weakCompareAndSetInt(o, wordOffset,
1993 fullWord, (fullWord & ~mask) | maskedX));
1994 return expected;
1995 }
1996
1997 @IntrinsicCandidate
1998 public final boolean compareAndSetByte(Object o, long offset,
1999 byte expected,
2000 byte x) {
2001 return compareAndExchangeByte(o, offset, expected, x) == expected;
2002 }
2003
2004 @IntrinsicCandidate
2005 public final boolean weakCompareAndSetByte(Object o, long offset,
2006 byte expected,
2007 byte x) {
2008 return compareAndSetByte(o, offset, expected, x);
2009 }
2010
2011 @IntrinsicCandidate
2012 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
2013 byte expected,
2014 byte x) {
2015 return weakCompareAndSetByte(o, offset, expected, x);
2016 }
2017
2018 @IntrinsicCandidate
2019 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
2020 byte expected,
2021 byte x) {
2022 return weakCompareAndSetByte(o, offset, expected, x);
2023 }
2024
2025 @IntrinsicCandidate
2026 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
2027 byte expected,
2028 byte x) {
2029 return weakCompareAndSetByte(o, offset, expected, x);
2030 }
2031
2032 @IntrinsicCandidate
2033 public final byte compareAndExchangeByteAcquire(Object o, long offset,
2034 byte expected,
2035 byte x) {
2036 return compareAndExchangeByte(o, offset, expected, x);
2037 }
2038
2039 @IntrinsicCandidate
2040 public final byte compareAndExchangeByteRelease(Object o, long offset,
2041 byte expected,
2042 byte x) {
2043 return compareAndExchangeByte(o, offset, expected, x);
2044 }
2045
2046 @IntrinsicCandidate
2047 public final short compareAndExchangeShort(Object o, long offset,
2048 short expected,
2049 short x) {
2050 if ((offset & 3) == 3) {
2051 throw new IllegalArgumentException("Update spans the word, not supported");
2052 }
2053 long wordOffset = offset & ~3;
2054 int shift = (int) (offset & 3) << 3;
2055 if (BIG_ENDIAN) {
2056 shift = 16 - shift;
2057 }
2058 int mask = 0xFFFF << shift;
2059 int maskedExpected = (expected & 0xFFFF) << shift;
2060 int maskedX = (x & 0xFFFF) << shift;
2061 int fullWord;
2062 do {
2063 fullWord = getIntVolatile(o, wordOffset);
2064 if ((fullWord & mask) != maskedExpected) {
2065 return (short) ((fullWord & mask) >> shift);
2066 }
2067 } while (!weakCompareAndSetInt(o, wordOffset,
2068 fullWord, (fullWord & ~mask) | maskedX));
2069 return expected;
2070 }
2071
2072 @IntrinsicCandidate
2073 public final boolean compareAndSetShort(Object o, long offset,
2074 short expected,
2075 short x) {
2076 return compareAndExchangeShort(o, offset, expected, x) == expected;
2077 }
2078
2079 @IntrinsicCandidate
2080 public final boolean weakCompareAndSetShort(Object o, long offset,
2081 short expected,
2082 short x) {
2083 return compareAndSetShort(o, offset, expected, x);
2084 }
2085
2086 @IntrinsicCandidate
2087 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
2088 short expected,
2089 short x) {
2090 return weakCompareAndSetShort(o, offset, expected, x);
2091 }
2092
2093 @IntrinsicCandidate
2094 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
2095 short expected,
2096 short x) {
2097 return weakCompareAndSetShort(o, offset, expected, x);
2098 }
2099
2100 @IntrinsicCandidate
2101 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
2102 short expected,
2103 short x) {
2104 return weakCompareAndSetShort(o, offset, expected, x);
2105 }
2106
2107
2108 @IntrinsicCandidate
2109 public final short compareAndExchangeShortAcquire(Object o, long offset,
2110 short expected,
2111 short x) {
2112 return compareAndExchangeShort(o, offset, expected, x);
2113 }
2114
2115 @IntrinsicCandidate
2116 public final short compareAndExchangeShortRelease(Object o, long offset,
2117 short expected,
2118 short x) {
2119 return compareAndExchangeShort(o, offset, expected, x);
2120 }
2121
2122 @ForceInline
2123 private char s2c(short s) {
2124 return (char) s;
2125 }
2126
2127 @ForceInline
2128 private short c2s(char s) {
2129 return (short) s;
2130 }
2131
2132 @ForceInline
2133 public final boolean compareAndSetChar(Object o, long offset,
2134 char expected,
2135 char x) {
2136 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
2137 }
2138
2139 @ForceInline
2140 public final char compareAndExchangeChar(Object o, long offset,
2141 char expected,
2142 char x) {
2143 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
2144 }
2145
2146 @ForceInline
2147 public final char compareAndExchangeCharAcquire(Object o, long offset,
2148 char expected,
2149 char x) {
2150 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
2151 }
2152
2153 @ForceInline
2154 public final char compareAndExchangeCharRelease(Object o, long offset,
2155 char expected,
2156 char x) {
2157 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
2158 }
2159
2160 @ForceInline
2161 public final boolean weakCompareAndSetChar(Object o, long offset,
2162 char expected,
2163 char x) {
2164 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
2165 }
2166
2167 @ForceInline
2168 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
2169 char expected,
2170 char x) {
2171 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
2172 }
2173
2174 @ForceInline
2175 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
2176 char expected,
2177 char x) {
2178 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
2179 }
2180
2181 @ForceInline
2182 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
2183 char expected,
2184 char x) {
2185 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
2186 }
2187
2188 /**
2189 * The JVM converts integral values to boolean values using two
2190 * different conventions, byte testing against zero and truncation
2191 * to least-significant bit.
2192 *
2193 * <p>The JNI documents specify that, at least for returning
2194 * values from native methods, a Java boolean value is converted
2195 * to the value-set 0..1 by first truncating to a byte (0..255 or
2196 * maybe -128..127) and then testing against zero. Thus, Java
2197 * booleans in non-Java data structures are by convention
2198 * represented as 8-bit containers containing either zero (for
2199 * false) or any non-zero value (for true).
2200 *
2201 * <p>Java booleans in the heap are also stored in bytes, but are
2202 * strongly normalized to the value-set 0..1 (i.e., they are
2203 * truncated to the least-significant bit).
2204 *
2205 * <p>The main reason for having different conventions for
2206 * conversion is performance: Truncation to the least-significant
2207 * bit can be usually implemented with fewer (machine)
2208 * instructions than byte testing against zero.
2209 *
2210 * <p>A number of Unsafe methods load boolean values from the heap
2211 * as bytes. Unsafe converts those values according to the JNI
2212 * rules (i.e, using the "testing against zero" convention). The
2213 * method {@code byte2bool} implements that conversion.
2214 *
2215 * @param b the byte to be converted to boolean
2216 * @return the result of the conversion
2217 */
2218 @ForceInline
2219 private boolean byte2bool(byte b) {
2220 return b != 0;
2221 }
2222
2223 /**
2224 * Convert a boolean value to a byte. The return value is strongly
2225 * normalized to the value-set 0..1 (i.e., the value is truncated
2226 * to the least-significant bit). See {@link #byte2bool(byte)} for
2227 * more details on conversion conventions.
2228 *
2229 * @param b the boolean to be converted to byte (and then normalized)
2230 * @return the result of the conversion
2231 */
2232 @ForceInline
2233 private byte bool2byte(boolean b) {
2234 return b ? (byte)1 : (byte)0;
2235 }
2236
2237 @ForceInline
2238 public final boolean compareAndSetBoolean(Object o, long offset,
2239 boolean expected,
2240 boolean x) {
2241 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
2242 }
2243
2244 @ForceInline
2245 public final boolean compareAndExchangeBoolean(Object o, long offset,
2246 boolean expected,
2247 boolean x) {
2248 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
2249 }
2250
2251 @ForceInline
2252 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
2253 boolean expected,
2254 boolean x) {
2255 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
2256 }
2257
2258 @ForceInline
2259 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
2260 boolean expected,
2261 boolean x) {
2262 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
2263 }
2264
2265 @ForceInline
2266 public final boolean weakCompareAndSetBoolean(Object o, long offset,
2267 boolean expected,
2268 boolean x) {
2269 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
2270 }
2271
2272 @ForceInline
2273 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
2274 boolean expected,
2275 boolean x) {
2276 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
2277 }
2278
2279 @ForceInline
2280 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
2281 boolean expected,
2282 boolean x) {
2283 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
2284 }
2285
2286 @ForceInline
2287 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
2288 boolean expected,
2289 boolean x) {
2290 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
2291 }
2292
2293 /**
2294 * Atomically updates Java variable to {@code x} if it is currently
2295 * holding {@code expected}.
2296 *
2297 * <p>This operation has memory semantics of a {@code volatile} read
2298 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2299 *
2300 * @return {@code true} if successful
2301 */
2302 @ForceInline
2303 public final boolean compareAndSetFloat(Object o, long offset,
2304 float expected,
2305 float x) {
2306 return compareAndSetInt(o, offset,
2307 Float.floatToRawIntBits(expected),
2308 Float.floatToRawIntBits(x));
2309 }
2310
2311 @ForceInline
2312 public final float compareAndExchangeFloat(Object o, long offset,
2313 float expected,
2314 float x) {
2315 int w = compareAndExchangeInt(o, offset,
2316 Float.floatToRawIntBits(expected),
2317 Float.floatToRawIntBits(x));
2318 return Float.intBitsToFloat(w);
2319 }
2320
2321 @ForceInline
2322 public final float compareAndExchangeFloatAcquire(Object o, long offset,
2323 float expected,
2324 float x) {
2325 int w = compareAndExchangeIntAcquire(o, offset,
2326 Float.floatToRawIntBits(expected),
2327 Float.floatToRawIntBits(x));
2328 return Float.intBitsToFloat(w);
2329 }
2330
2331 @ForceInline
2332 public final float compareAndExchangeFloatRelease(Object o, long offset,
2333 float expected,
2334 float x) {
2335 int w = compareAndExchangeIntRelease(o, offset,
2336 Float.floatToRawIntBits(expected),
2337 Float.floatToRawIntBits(x));
2338 return Float.intBitsToFloat(w);
2339 }
2340
2341 @ForceInline
2342 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
2343 float expected,
2344 float x) {
2345 return weakCompareAndSetIntPlain(o, offset,
2346 Float.floatToRawIntBits(expected),
2347 Float.floatToRawIntBits(x));
2348 }
2349
2350 @ForceInline
2351 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
2352 float expected,
2353 float x) {
2354 return weakCompareAndSetIntAcquire(o, offset,
2355 Float.floatToRawIntBits(expected),
2356 Float.floatToRawIntBits(x));
2357 }
2358
2359 @ForceInline
2360 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
2361 float expected,
2362 float x) {
2363 return weakCompareAndSetIntRelease(o, offset,
2364 Float.floatToRawIntBits(expected),
2365 Float.floatToRawIntBits(x));
2366 }
2367
2368 @ForceInline
2369 public final boolean weakCompareAndSetFloat(Object o, long offset,
2370 float expected,
2371 float x) {
2372 return weakCompareAndSetInt(o, offset,
2373 Float.floatToRawIntBits(expected),
2374 Float.floatToRawIntBits(x));
2375 }
2376
2377 /**
2378 * Atomically updates Java variable to {@code x} if it is currently
2379 * holding {@code expected}.
2380 *
2381 * <p>This operation has memory semantics of a {@code volatile} read
2382 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2383 *
2384 * @return {@code true} if successful
2385 */
2386 @ForceInline
2387 public final boolean compareAndSetDouble(Object o, long offset,
2388 double expected,
2389 double x) {
2390 return compareAndSetLong(o, offset,
2391 Double.doubleToRawLongBits(expected),
2392 Double.doubleToRawLongBits(x));
2393 }
2394
2395 @ForceInline
2396 public final double compareAndExchangeDouble(Object o, long offset,
2397 double expected,
2398 double x) {
2399 long w = compareAndExchangeLong(o, offset,
2400 Double.doubleToRawLongBits(expected),
2401 Double.doubleToRawLongBits(x));
2402 return Double.longBitsToDouble(w);
2403 }
2404
2405 @ForceInline
2406 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
2407 double expected,
2408 double x) {
2409 long w = compareAndExchangeLongAcquire(o, offset,
2410 Double.doubleToRawLongBits(expected),
2411 Double.doubleToRawLongBits(x));
2412 return Double.longBitsToDouble(w);
2413 }
2414
2415 @ForceInline
2416 public final double compareAndExchangeDoubleRelease(Object o, long offset,
2417 double expected,
2418 double x) {
2419 long w = compareAndExchangeLongRelease(o, offset,
2420 Double.doubleToRawLongBits(expected),
2421 Double.doubleToRawLongBits(x));
2422 return Double.longBitsToDouble(w);
2423 }
2424
2425 @ForceInline
2426 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
2427 double expected,
2428 double x) {
2429 return weakCompareAndSetLongPlain(o, offset,
2430 Double.doubleToRawLongBits(expected),
2431 Double.doubleToRawLongBits(x));
2432 }
2433
2434 @ForceInline
2435 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
2436 double expected,
2437 double x) {
2438 return weakCompareAndSetLongAcquire(o, offset,
2439 Double.doubleToRawLongBits(expected),
2440 Double.doubleToRawLongBits(x));
2441 }
2442
2443 @ForceInline
2444 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
2445 double expected,
2446 double x) {
2447 return weakCompareAndSetLongRelease(o, offset,
2448 Double.doubleToRawLongBits(expected),
2449 Double.doubleToRawLongBits(x));
2450 }
2451
2452 @ForceInline
2453 public final boolean weakCompareAndSetDouble(Object o, long offset,
2454 double expected,
2455 double x) {
2456 return weakCompareAndSetLong(o, offset,
2457 Double.doubleToRawLongBits(expected),
2458 Double.doubleToRawLongBits(x));
2459 }
2460
2461 /**
2462 * Atomically updates Java variable to {@code x} if it is currently
2463 * holding {@code expected}.
2464 *
2465 * <p>This operation has memory semantics of a {@code volatile} read
2466 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2467 *
2468 * @return {@code true} if successful
2469 */
2470 @IntrinsicCandidate
2471 public final native boolean compareAndSetLong(Object o, long offset,
2472 long expected,
2473 long x);
2474
2475 @IntrinsicCandidate
2476 public final native long compareAndExchangeLong(Object o, long offset,
2477 long expected,
2478 long x);
2479
2480 @IntrinsicCandidate
2481 public final long compareAndExchangeLongAcquire(Object o, long offset,
2482 long expected,
2483 long x) {
2484 return compareAndExchangeLong(o, offset, expected, x);
2485 }
2486
2487 @IntrinsicCandidate
2488 public final long compareAndExchangeLongRelease(Object o, long offset,
2489 long expected,
2490 long x) {
2491 return compareAndExchangeLong(o, offset, expected, x);
2492 }
2493
2494 @IntrinsicCandidate
2495 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2496 long expected,
2497 long x) {
2498 return compareAndSetLong(o, offset, expected, x);
2499 }
2500
2501 @IntrinsicCandidate
2502 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2503 long expected,
2504 long x) {
2505 return compareAndSetLong(o, offset, expected, x);
2506 }
2507
2508 @IntrinsicCandidate
2509 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2510 long expected,
2511 long x) {
2512 return compareAndSetLong(o, offset, expected, x);
2513 }
2514
2515 @IntrinsicCandidate
2516 public final boolean weakCompareAndSetLong(Object o, long offset,
2517 long expected,
2518 long x) {
2519 return compareAndSetLong(o, offset, expected, x);
2520 }
2521
2522 /**
2523 * Fetches a reference value from a given Java variable, with volatile
2524 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2525 */
2526 @IntrinsicCandidate
2527 public native Object getReferenceVolatile(Object o, long offset);
2528
2529 @ForceInline
2530 public final <V> Object getFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType) {
2531 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2532 Object res = getFlatValue(o, offset, layout, valueType);
2533 fullFence();
2534 return res;
2535 }
2536
2537 /**
2538 * Stores a reference value into a given Java variable, with
2539 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2540 */
2541 @IntrinsicCandidate
2542 public native void putReferenceVolatile(Object o, long offset, Object x);
2543
2544 @ForceInline
2545 public final <V> void putFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType, V x) {
2546 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2547 putFlatValueRelease(o, offset, layout, valueType, x);
2548 fullFence();
2549 }
2550
2551 /** Volatile version of {@link #getInt(Object, long)} */
2552 @IntrinsicCandidate
2553 public native int getIntVolatile(Object o, long offset);
2554
2555 /** Volatile version of {@link #putInt(Object, long, int)} */
2556 @IntrinsicCandidate
2557 public native void putIntVolatile(Object o, long offset, int x);
2558
2559 /** Volatile version of {@link #getBoolean(Object, long)} */
2560 @IntrinsicCandidate
2561 public native boolean getBooleanVolatile(Object o, long offset);
2562
2563 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2564 @IntrinsicCandidate
2565 public native void putBooleanVolatile(Object o, long offset, boolean x);
2566
2567 /** Volatile version of {@link #getByte(Object, long)} */
2568 @IntrinsicCandidate
2569 public native byte getByteVolatile(Object o, long offset);
2570
2571 /** Volatile version of {@link #putByte(Object, long, byte)} */
2572 @IntrinsicCandidate
2573 public native void putByteVolatile(Object o, long offset, byte x);
2574
2575 /** Volatile version of {@link #getShort(Object, long)} */
2576 @IntrinsicCandidate
2577 public native short getShortVolatile(Object o, long offset);
2578
2579 /** Volatile version of {@link #putShort(Object, long, short)} */
2580 @IntrinsicCandidate
2581 public native void putShortVolatile(Object o, long offset, short x);
2582
2583 /** Volatile version of {@link #getChar(Object, long)} */
2584 @IntrinsicCandidate
2585 public native char getCharVolatile(Object o, long offset);
2586
2587 /** Volatile version of {@link #putChar(Object, long, char)} */
2588 @IntrinsicCandidate
2589 public native void putCharVolatile(Object o, long offset, char x);
2590
2591 /** Volatile version of {@link #getLong(Object, long)} */
2592 @IntrinsicCandidate
2593 public native long getLongVolatile(Object o, long offset);
2594
2595 /** Volatile version of {@link #putLong(Object, long, long)} */
2596 @IntrinsicCandidate
2597 public native void putLongVolatile(Object o, long offset, long x);
2598
2599 /** Volatile version of {@link #getFloat(Object, long)} */
2600 @IntrinsicCandidate
2601 public native float getFloatVolatile(Object o, long offset);
2602
2603 /** Volatile version of {@link #putFloat(Object, long, float)} */
2604 @IntrinsicCandidate
2605 public native void putFloatVolatile(Object o, long offset, float x);
2606
2607 /** Volatile version of {@link #getDouble(Object, long)} */
2608 @IntrinsicCandidate
2609 public native double getDoubleVolatile(Object o, long offset);
2610
2611 /** Volatile version of {@link #putDouble(Object, long, double)} */
2612 @IntrinsicCandidate
2613 public native void putDoubleVolatile(Object o, long offset, double x);
2614
2615
2616
2617 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2618 @IntrinsicCandidate
2619 public final Object getReferenceAcquire(Object o, long offset) {
2620 return getReferenceVolatile(o, offset);
2621 }
2622
2623 @ForceInline
2624 public final <V> Object getFlatValueAcquire(Object o, long offset, int layout, Class<?> valueType) {
2625 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2626 Object res = getFlatValue(o, offset, layout, valueType);
2627 loadFence();
2628 return res;
2629 }
2630
2631 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2632 @IntrinsicCandidate
2633 public final boolean getBooleanAcquire(Object o, long offset) {
2634 return getBooleanVolatile(o, offset);
2635 }
2636
2637 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2638 @IntrinsicCandidate
2639 public final byte getByteAcquire(Object o, long offset) {
2640 return getByteVolatile(o, offset);
2641 }
2642
2643 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2644 @IntrinsicCandidate
2645 public final short getShortAcquire(Object o, long offset) {
2646 return getShortVolatile(o, offset);
2647 }
2648
2649 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2650 @IntrinsicCandidate
2651 public final char getCharAcquire(Object o, long offset) {
2652 return getCharVolatile(o, offset);
2653 }
2654
2655 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2656 @IntrinsicCandidate
2657 public final int getIntAcquire(Object o, long offset) {
2658 return getIntVolatile(o, offset);
2659 }
2660
2661 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2662 @IntrinsicCandidate
2663 public final float getFloatAcquire(Object o, long offset) {
2664 return getFloatVolatile(o, offset);
2665 }
2666
2667 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2668 @IntrinsicCandidate
2669 public final long getLongAcquire(Object o, long offset) {
2670 return getLongVolatile(o, offset);
2671 }
2672
2673 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2674 @IntrinsicCandidate
2675 public final double getDoubleAcquire(Object o, long offset) {
2676 return getDoubleVolatile(o, offset);
2677 }
2678
2679 /*
2680 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2681 * that do not guarantee immediate visibility of the store to
2682 * other threads. This method is generally only useful if the
2683 * underlying field is a Java volatile (or if an array cell, one
2684 * that is otherwise only accessed using volatile accesses).
2685 *
2686 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2687 */
2688
2689 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2690 @IntrinsicCandidate
2691 public final void putReferenceRelease(Object o, long offset, Object x) {
2692 putReferenceVolatile(o, offset, x);
2693 }
2694
2695 @ForceInline
2696 public final <V> void putFlatValueRelease(Object o, long offset, int layout, Class<?> valueType, V x) {
2697 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2698 storeFence();
2699 putFlatValue(o, offset, layout, valueType, x);
2700 }
2701
2702 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2703 @IntrinsicCandidate
2704 public final void putBooleanRelease(Object o, long offset, boolean x) {
2705 putBooleanVolatile(o, offset, x);
2706 }
2707
2708 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2709 @IntrinsicCandidate
2710 public final void putByteRelease(Object o, long offset, byte x) {
2711 putByteVolatile(o, offset, x);
2712 }
2713
2714 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2715 @IntrinsicCandidate
2716 public final void putShortRelease(Object o, long offset, short x) {
2717 putShortVolatile(o, offset, x);
2718 }
2719
2720 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2721 @IntrinsicCandidate
2722 public final void putCharRelease(Object o, long offset, char x) {
2723 putCharVolatile(o, offset, x);
2724 }
2725
2726 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2727 @IntrinsicCandidate
2728 public final void putIntRelease(Object o, long offset, int x) {
2729 putIntVolatile(o, offset, x);
2730 }
2731
2732 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2733 @IntrinsicCandidate
2734 public final void putFloatRelease(Object o, long offset, float x) {
2735 putFloatVolatile(o, offset, x);
2736 }
2737
2738 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2739 @IntrinsicCandidate
2740 public final void putLongRelease(Object o, long offset, long x) {
2741 putLongVolatile(o, offset, x);
2742 }
2743
2744 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2745 @IntrinsicCandidate
2746 public final void putDoubleRelease(Object o, long offset, double x) {
2747 putDoubleVolatile(o, offset, x);
2748 }
2749
2750 // ------------------------------ Opaque --------------------------------------
2751
2752 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2753 @IntrinsicCandidate
2754 public final Object getReferenceOpaque(Object o, long offset) {
2755 return getReferenceVolatile(o, offset);
2756 }
2757
2758 @ForceInline
2759 public final <V> Object getFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType) {
2760 // this is stronger than opaque semantics
2761 return getFlatValueAcquire(o, offset, layout, valueType);
2762 }
2763
2764 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2765 @IntrinsicCandidate
2766 public final boolean getBooleanOpaque(Object o, long offset) {
2767 return getBooleanVolatile(o, offset);
2768 }
2769
2770 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2771 @IntrinsicCandidate
2772 public final byte getByteOpaque(Object o, long offset) {
2773 return getByteVolatile(o, offset);
2774 }
2775
2776 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2777 @IntrinsicCandidate
2778 public final short getShortOpaque(Object o, long offset) {
2779 return getShortVolatile(o, offset);
2780 }
2781
2782 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2783 @IntrinsicCandidate
2784 public final char getCharOpaque(Object o, long offset) {
2785 return getCharVolatile(o, offset);
2786 }
2787
2788 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2789 @IntrinsicCandidate
2790 public final int getIntOpaque(Object o, long offset) {
2791 return getIntVolatile(o, offset);
2792 }
2793
2794 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2795 @IntrinsicCandidate
2796 public final float getFloatOpaque(Object o, long offset) {
2797 return getFloatVolatile(o, offset);
2798 }
2799
2800 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2801 @IntrinsicCandidate
2802 public final long getLongOpaque(Object o, long offset) {
2803 return getLongVolatile(o, offset);
2804 }
2805
2806 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2807 @IntrinsicCandidate
2808 public final double getDoubleOpaque(Object o, long offset) {
2809 return getDoubleVolatile(o, offset);
2810 }
2811
2812 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2813 @IntrinsicCandidate
2814 public final void putReferenceOpaque(Object o, long offset, Object x) {
2815 putReferenceVolatile(o, offset, x);
2816 }
2817
2818 @ForceInline
2819 public final <V> void putFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType, V x) {
2820 // this is stronger than opaque semantics
2821 putFlatValueRelease(o, offset, layout, valueType, x);
2822 }
2823
2824 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2825 @IntrinsicCandidate
2826 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2827 putBooleanVolatile(o, offset, x);
2828 }
2829
2830 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2831 @IntrinsicCandidate
2832 public final void putByteOpaque(Object o, long offset, byte x) {
2833 putByteVolatile(o, offset, x);
2834 }
2835
2836 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2837 @IntrinsicCandidate
2838 public final void putShortOpaque(Object o, long offset, short x) {
2839 putShortVolatile(o, offset, x);
2840 }
2841
2842 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2843 @IntrinsicCandidate
2844 public final void putCharOpaque(Object o, long offset, char x) {
2845 putCharVolatile(o, offset, x);
2846 }
2847
2848 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2849 @IntrinsicCandidate
2850 public final void putIntOpaque(Object o, long offset, int x) {
2851 putIntVolatile(o, offset, x);
2852 }
2853
2854 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2855 @IntrinsicCandidate
2856 public final void putFloatOpaque(Object o, long offset, float x) {
2857 putFloatVolatile(o, offset, x);
2858 }
2859
2860 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2861 @IntrinsicCandidate
2862 public final void putLongOpaque(Object o, long offset, long x) {
2863 putLongVolatile(o, offset, x);
2864 }
2865
2866 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2867 @IntrinsicCandidate
2868 public final void putDoubleOpaque(Object o, long offset, double x) {
2869 putDoubleVolatile(o, offset, x);
2870 }
2871
2872 @ForceInline
2873 private boolean compareAndSetFlatValueAsBytes(Object o, long offset, int layout, Class<?> valueType, Object expected, Object x) {
2874 // We turn the payload of an atomic value into a numeric value (of suitable type)
2875 // by storing the value into an array element (of matching layout) and by reading
2876 // back the array element as an integral value. After which we can implement the CAS
2877 // as a plain numeric CAS. Note: this only works if the payload contains no oops
2878 // (see VarHandles::isAtomicFlat).
2879 Object[] expectedArray = newSpecialArray(valueType, 1, layout);
2880 Object xArray = newSpecialArray(valueType, 1, layout);
2881 long base = arrayBaseOffset(expectedArray);
2882 int scale = arrayIndexScale(expectedArray);
2883 putFlatValue(expectedArray, base, layout, valueType, expected);
2884 putFlatValue(xArray, base, layout, valueType, x);
2885 switch (scale) {
2886 case 1: {
2887 byte expectedByte = getByte(expectedArray, base);
2888 byte xByte = getByte(xArray, base);
2889 return compareAndSetByte(o, offset, expectedByte, xByte);
2890 }
2891 case 2: {
2892 short expectedShort = getShort(expectedArray, base);
2893 short xShort = getShort(xArray, base);
2894 return compareAndSetShort(o, offset, expectedShort, xShort);
2895 }
2896 case 4: {
2897 int expectedInt = getInt(expectedArray, base);
2898 int xInt = getInt(xArray, base);
2899 return compareAndSetInt(o, offset, expectedInt, xInt);
2900 }
2901 case 8: {
2902 long expectedLong = getLong(expectedArray, base);
2903 long xLong = getLong(xArray, base);
2904 return compareAndSetLong(o, offset, expectedLong, xLong);
2905 }
2906 default: {
2907 throw new UnsupportedOperationException();
2908 }
2909 }
2910 }
2911
2912 /**
2913 * Unblocks the given thread blocked on {@code park}, or, if it is
2914 * not blocked, causes the subsequent call to {@code park} not to
2915 * block. Note: this operation is "unsafe" solely because the
2916 * caller must somehow ensure that the thread has not been
2917 * destroyed. Nothing special is usually required to ensure this
2918 * when called from Java (in which there will ordinarily be a live
2919 * reference to the thread) but this is not nearly-automatically
2920 * so when calling from native code.
2921 *
2922 * @param thread the thread to unpark.
2923 */
2924 @IntrinsicCandidate
2925 public native void unpark(Object thread);
2926
2927 /**
2928 * Blocks current thread, returning when a balancing
2929 * {@code unpark} occurs, or a balancing {@code unpark} has
2930 * already occurred, or the thread is interrupted, or, if not
2931 * absolute and time is not zero, the given time nanoseconds have
2932 * elapsed, or if absolute, the given deadline in milliseconds
2933 * since Epoch has passed, or spuriously (i.e., returning for no
2934 * "reason"). Note: This operation is in the Unsafe class only
2935 * because {@code unpark} is, so it would be strange to place it
2936 * elsewhere.
2937 */
2938 @IntrinsicCandidate
2939 public native void park(boolean isAbsolute, long time);
2940
2941 /**
2942 * Gets the load average in the system run queue assigned
2943 * to the available processors averaged over various periods of time.
2944 * This method retrieves the given {@code nelem} samples and
2945 * assigns to the elements of the given {@code loadavg} array.
2946 * The system imposes a maximum of 3 samples, representing
2947 * averages over the last 1, 5, and 15 minutes, respectively.
2948 *
2949 * @param loadavg an array of double of size nelems
2950 * @param nelems the number of samples to be retrieved and
2951 * must be 1 to 3.
2952 *
2953 * @return the number of samples actually retrieved; or -1
2954 * if the load average is unobtainable.
2955 */
2956 public int getLoadAverage(double[] loadavg, int nelems) {
2957 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2958 throw new ArrayIndexOutOfBoundsException();
2959 }
2960
2961 return getLoadAverage0(loadavg, nelems);
2962 }
2963
2964 // The following contain CAS-based Java implementations used on
2965 // platforms not supporting native instructions
2966
2967 /**
2968 * Atomically adds the given value to the current value of a field
2969 * or array element within the given object {@code o}
2970 * at the given {@code offset}.
2971 *
2972 * @param o object/array to update the field/element in
2973 * @param offset field/element offset
2974 * @param delta the value to add
2975 * @return the previous value
2976 * @since 1.8
2977 */
2978 @IntrinsicCandidate
2979 public final int getAndAddInt(Object o, long offset, int delta) {
2980 int v;
2981 do {
2982 v = getIntVolatile(o, offset);
2983 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
2984 return v;
2985 }
2986
2987 @ForceInline
2988 public final int getAndAddIntRelease(Object o, long offset, int delta) {
2989 int v;
2990 do {
2991 v = getInt(o, offset);
2992 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
2993 return v;
2994 }
2995
2996 @ForceInline
2997 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
2998 int v;
2999 do {
3000 v = getIntAcquire(o, offset);
3001 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
3002 return v;
3003 }
3004
3005 /**
3006 * Atomically adds the given value to the current value of a field
3007 * or array element within the given object {@code o}
3008 * at the given {@code offset}.
3009 *
3010 * @param o object/array to update the field/element in
3011 * @param offset field/element offset
3012 * @param delta the value to add
3013 * @return the previous value
3014 * @since 1.8
3015 */
3016 @IntrinsicCandidate
3017 public final long getAndAddLong(Object o, long offset, long delta) {
3018 long v;
3019 do {
3020 v = getLongVolatile(o, offset);
3021 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
3022 return v;
3023 }
3024
3025 @ForceInline
3026 public final long getAndAddLongRelease(Object o, long offset, long delta) {
3027 long v;
3028 do {
3029 v = getLong(o, offset);
3030 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
3031 return v;
3032 }
3033
3034 @ForceInline
3035 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
3036 long v;
3037 do {
3038 v = getLongAcquire(o, offset);
3039 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
3040 return v;
3041 }
3042
3043 @IntrinsicCandidate
3044 public final byte getAndAddByte(Object o, long offset, byte delta) {
3045 byte v;
3046 do {
3047 v = getByteVolatile(o, offset);
3048 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
3049 return v;
3050 }
3051
3052 @ForceInline
3053 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
3054 byte v;
3055 do {
3056 v = getByte(o, offset);
3057 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
3058 return v;
3059 }
3060
3061 @ForceInline
3062 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
3063 byte v;
3064 do {
3065 v = getByteAcquire(o, offset);
3066 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
3067 return v;
3068 }
3069
3070 @IntrinsicCandidate
3071 public final short getAndAddShort(Object o, long offset, short delta) {
3072 short v;
3073 do {
3074 v = getShortVolatile(o, offset);
3075 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
3076 return v;
3077 }
3078
3079 @ForceInline
3080 public final short getAndAddShortRelease(Object o, long offset, short delta) {
3081 short v;
3082 do {
3083 v = getShort(o, offset);
3084 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
3085 return v;
3086 }
3087
3088 @ForceInline
3089 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
3090 short v;
3091 do {
3092 v = getShortAcquire(o, offset);
3093 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
3094 return v;
3095 }
3096
3097 @ForceInline
3098 public final char getAndAddChar(Object o, long offset, char delta) {
3099 return (char) getAndAddShort(o, offset, (short) delta);
3100 }
3101
3102 @ForceInline
3103 public final char getAndAddCharRelease(Object o, long offset, char delta) {
3104 return (char) getAndAddShortRelease(o, offset, (short) delta);
3105 }
3106
3107 @ForceInline
3108 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
3109 return (char) getAndAddShortAcquire(o, offset, (short) delta);
3110 }
3111
3112 @ForceInline
3113 public final float getAndAddFloat(Object o, long offset, float delta) {
3114 int expectedBits;
3115 float v;
3116 do {
3117 // Load and CAS with the raw bits to avoid issues with NaNs and
3118 // possible bit conversion from signaling NaNs to quiet NaNs that
3119 // may result in the loop not terminating.
3120 expectedBits = getIntVolatile(o, offset);
3121 v = Float.intBitsToFloat(expectedBits);
3122 } while (!weakCompareAndSetInt(o, offset,
3123 expectedBits, Float.floatToRawIntBits(v + delta)));
3124 return v;
3125 }
3126
3127 @ForceInline
3128 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
3129 int expectedBits;
3130 float v;
3131 do {
3132 // Load and CAS with the raw bits to avoid issues with NaNs and
3133 // possible bit conversion from signaling NaNs to quiet NaNs that
3134 // may result in the loop not terminating.
3135 expectedBits = getInt(o, offset);
3136 v = Float.intBitsToFloat(expectedBits);
3137 } while (!weakCompareAndSetIntRelease(o, offset,
3138 expectedBits, Float.floatToRawIntBits(v + delta)));
3139 return v;
3140 }
3141
3142 @ForceInline
3143 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
3144 int expectedBits;
3145 float v;
3146 do {
3147 // Load and CAS with the raw bits to avoid issues with NaNs and
3148 // possible bit conversion from signaling NaNs to quiet NaNs that
3149 // may result in the loop not terminating.
3150 expectedBits = getIntAcquire(o, offset);
3151 v = Float.intBitsToFloat(expectedBits);
3152 } while (!weakCompareAndSetIntAcquire(o, offset,
3153 expectedBits, Float.floatToRawIntBits(v + delta)));
3154 return v;
3155 }
3156
3157 @ForceInline
3158 public final double getAndAddDouble(Object o, long offset, double delta) {
3159 long expectedBits;
3160 double v;
3161 do {
3162 // Load and CAS with the raw bits to avoid issues with NaNs and
3163 // possible bit conversion from signaling NaNs to quiet NaNs that
3164 // may result in the loop not terminating.
3165 expectedBits = getLongVolatile(o, offset);
3166 v = Double.longBitsToDouble(expectedBits);
3167 } while (!weakCompareAndSetLong(o, offset,
3168 expectedBits, Double.doubleToRawLongBits(v + delta)));
3169 return v;
3170 }
3171
3172 @ForceInline
3173 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
3174 long expectedBits;
3175 double v;
3176 do {
3177 // Load and CAS with the raw bits to avoid issues with NaNs and
3178 // possible bit conversion from signaling NaNs to quiet NaNs that
3179 // may result in the loop not terminating.
3180 expectedBits = getLong(o, offset);
3181 v = Double.longBitsToDouble(expectedBits);
3182 } while (!weakCompareAndSetLongRelease(o, offset,
3183 expectedBits, Double.doubleToRawLongBits(v + delta)));
3184 return v;
3185 }
3186
3187 @ForceInline
3188 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
3189 long expectedBits;
3190 double v;
3191 do {
3192 // Load and CAS with the raw bits to avoid issues with NaNs and
3193 // possible bit conversion from signaling NaNs to quiet NaNs that
3194 // may result in the loop not terminating.
3195 expectedBits = getLongAcquire(o, offset);
3196 v = Double.longBitsToDouble(expectedBits);
3197 } while (!weakCompareAndSetLongAcquire(o, offset,
3198 expectedBits, Double.doubleToRawLongBits(v + delta)));
3199 return v;
3200 }
3201
3202 /**
3203 * Atomically exchanges the given value with the current value of
3204 * a field or array element within the given object {@code o}
3205 * at the given {@code offset}.
3206 *
3207 * @param o object/array to update the field/element in
3208 * @param offset field/element offset
3209 * @param newValue new value
3210 * @return the previous value
3211 * @since 1.8
3212 */
3213 @IntrinsicCandidate
3214 public final int getAndSetInt(Object o, long offset, int newValue) {
3215 int v;
3216 do {
3217 v = getIntVolatile(o, offset);
3218 } while (!weakCompareAndSetInt(o, offset, v, newValue));
3219 return v;
3220 }
3221
3222 @ForceInline
3223 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
3224 int v;
3225 do {
3226 v = getInt(o, offset);
3227 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
3228 return v;
3229 }
3230
3231 @ForceInline
3232 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
3233 int v;
3234 do {
3235 v = getIntAcquire(o, offset);
3236 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
3237 return v;
3238 }
3239
3240 /**
3241 * Atomically exchanges the given value with the current value of
3242 * a field or array element within the given object {@code o}
3243 * at the given {@code offset}.
3244 *
3245 * @param o object/array to update the field/element in
3246 * @param offset field/element offset
3247 * @param newValue new value
3248 * @return the previous value
3249 * @since 1.8
3250 */
3251 @IntrinsicCandidate
3252 public final long getAndSetLong(Object o, long offset, long newValue) {
3253 long v;
3254 do {
3255 v = getLongVolatile(o, offset);
3256 } while (!weakCompareAndSetLong(o, offset, v, newValue));
3257 return v;
3258 }
3259
3260 @ForceInline
3261 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
3262 long v;
3263 do {
3264 v = getLong(o, offset);
3265 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
3266 return v;
3267 }
3268
3269 @ForceInline
3270 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
3271 long v;
3272 do {
3273 v = getLongAcquire(o, offset);
3274 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
3275 return v;
3276 }
3277
3278 /**
3279 * Atomically exchanges the given reference value with the current
3280 * reference value of a field or array element within the given
3281 * object {@code o} at the given {@code offset}.
3282 *
3283 * @param o object/array to update the field/element in
3284 * @param offset field/element offset
3285 * @param newValue new value
3286 * @return the previous value
3287 * @since 1.8
3288 */
3289 @IntrinsicCandidate
3290 public final Object getAndSetReference(Object o, long offset, Object newValue) {
3291 Object v;
3292 do {
3293 v = getReferenceVolatile(o, offset);
3294 } while (!weakCompareAndSetReference(o, offset, v, newValue));
3295 return v;
3296 }
3297
3298 @ForceInline
3299 public final Object getAndSetReference(Object o, long offset, Class<?> valueType, Object newValue) {
3300 Object v;
3301 do {
3302 v = getReferenceVolatile(o, offset);
3303 } while (!compareAndSetReference(o, offset, valueType, v, newValue));
3304 return v;
3305 }
3306
3307 @ForceInline
3308 public Object getAndSetFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, Object newValue) {
3309 Object v;
3310 do {
3311 v = getFlatValueVolatile(o, offset, layoutKind, valueType);
3312 } while (!compareAndSetFlatValue(o, offset, layoutKind, valueType, v, newValue));
3313 return v;
3314 }
3315
3316 @ForceInline
3317 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
3318 Object v;
3319 do {
3320 v = getReference(o, offset);
3321 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
3322 return v;
3323 }
3324
3325 @ForceInline
3326 public final Object getAndSetReferenceRelease(Object o, long offset, Class<?> valueType, Object newValue) {
3327 return getAndSetReference(o, offset, valueType, newValue);
3328 }
3329
3330 @ForceInline
3331 public Object getAndSetFlatValueRelease(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3332 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3333 }
3334
3335 @ForceInline
3336 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
3337 Object v;
3338 do {
3339 v = getReferenceAcquire(o, offset);
3340 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
3341 return v;
3342 }
3343
3344 @ForceInline
3345 public final Object getAndSetReferenceAcquire(Object o, long offset, Class<?> valueType, Object newValue) {
3346 return getAndSetReference(o, offset, valueType, newValue);
3347 }
3348
3349 @ForceInline
3350 public Object getAndSetFlatValueAcquire(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3351 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3352 }
3353
3354 @IntrinsicCandidate
3355 public final byte getAndSetByte(Object o, long offset, byte newValue) {
3356 byte v;
3357 do {
3358 v = getByteVolatile(o, offset);
3359 } while (!weakCompareAndSetByte(o, offset, v, newValue));
3360 return v;
3361 }
3362
3363 @ForceInline
3364 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
3365 byte v;
3366 do {
3367 v = getByte(o, offset);
3368 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
3369 return v;
3370 }
3371
3372 @ForceInline
3373 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
3374 byte v;
3375 do {
3376 v = getByteAcquire(o, offset);
3377 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
3378 return v;
3379 }
3380
3381 @ForceInline
3382 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
3383 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
3384 }
3385
3386 @ForceInline
3387 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
3388 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
3389 }
3390
3391 @ForceInline
3392 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
3393 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
3394 }
3395
3396 @IntrinsicCandidate
3397 public final short getAndSetShort(Object o, long offset, short newValue) {
3398 short v;
3399 do {
3400 v = getShortVolatile(o, offset);
3401 } while (!weakCompareAndSetShort(o, offset, v, newValue));
3402 return v;
3403 }
3404
3405 @ForceInline
3406 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
3407 short v;
3408 do {
3409 v = getShort(o, offset);
3410 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
3411 return v;
3412 }
3413
3414 @ForceInline
3415 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
3416 short v;
3417 do {
3418 v = getShortAcquire(o, offset);
3419 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
3420 return v;
3421 }
3422
3423 @ForceInline
3424 public final char getAndSetChar(Object o, long offset, char newValue) {
3425 return s2c(getAndSetShort(o, offset, c2s(newValue)));
3426 }
3427
3428 @ForceInline
3429 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
3430 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
3431 }
3432
3433 @ForceInline
3434 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
3435 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
3436 }
3437
3438 @ForceInline
3439 public final float getAndSetFloat(Object o, long offset, float newValue) {
3440 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
3441 return Float.intBitsToFloat(v);
3442 }
3443
3444 @ForceInline
3445 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
3446 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
3447 return Float.intBitsToFloat(v);
3448 }
3449
3450 @ForceInline
3451 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
3452 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
3453 return Float.intBitsToFloat(v);
3454 }
3455
3456 @ForceInline
3457 public final double getAndSetDouble(Object o, long offset, double newValue) {
3458 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
3459 return Double.longBitsToDouble(v);
3460 }
3461
3462 @ForceInline
3463 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
3464 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
3465 return Double.longBitsToDouble(v);
3466 }
3467
3468 @ForceInline
3469 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
3470 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
3471 return Double.longBitsToDouble(v);
3472 }
3473
3474
3475 // The following contain CAS-based Java implementations used on
3476 // platforms not supporting native instructions
3477
3478 @ForceInline
3479 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
3480 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
3481 }
3482
3483 @ForceInline
3484 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
3485 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
3486 }
3487
3488 @ForceInline
3489 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
3490 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
3491 }
3492
3493 @ForceInline
3494 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
3495 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
3496 }
3497
3498 @ForceInline
3499 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
3500 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
3501 }
3502
3503 @ForceInline
3504 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
3505 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
3506 }
3507
3508 @ForceInline
3509 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
3510 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
3511 }
3512
3513 @ForceInline
3514 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
3515 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
3516 }
3517
3518 @ForceInline
3519 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
3520 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
3521 }
3522
3523
3524 @ForceInline
3525 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
3526 byte current;
3527 do {
3528 current = getByteVolatile(o, offset);
3529 } while (!weakCompareAndSetByte(o, offset,
3530 current, (byte) (current | mask)));
3531 return current;
3532 }
3533
3534 @ForceInline
3535 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
3536 byte current;
3537 do {
3538 current = getByte(o, offset);
3539 } while (!weakCompareAndSetByteRelease(o, offset,
3540 current, (byte) (current | mask)));
3541 return current;
3542 }
3543
3544 @ForceInline
3545 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
3546 byte current;
3547 do {
3548 // Plain read, the value is a hint, the acquire CAS does the work
3549 current = getByte(o, offset);
3550 } while (!weakCompareAndSetByteAcquire(o, offset,
3551 current, (byte) (current | mask)));
3552 return current;
3553 }
3554
3555 @ForceInline
3556 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
3557 byte current;
3558 do {
3559 current = getByteVolatile(o, offset);
3560 } while (!weakCompareAndSetByte(o, offset,
3561 current, (byte) (current & mask)));
3562 return current;
3563 }
3564
3565 @ForceInline
3566 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
3567 byte current;
3568 do {
3569 current = getByte(o, offset);
3570 } while (!weakCompareAndSetByteRelease(o, offset,
3571 current, (byte) (current & mask)));
3572 return current;
3573 }
3574
3575 @ForceInline
3576 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
3577 byte current;
3578 do {
3579 // Plain read, the value is a hint, the acquire CAS does the work
3580 current = getByte(o, offset);
3581 } while (!weakCompareAndSetByteAcquire(o, offset,
3582 current, (byte) (current & mask)));
3583 return current;
3584 }
3585
3586 @ForceInline
3587 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
3588 byte current;
3589 do {
3590 current = getByteVolatile(o, offset);
3591 } while (!weakCompareAndSetByte(o, offset,
3592 current, (byte) (current ^ mask)));
3593 return current;
3594 }
3595
3596 @ForceInline
3597 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
3598 byte current;
3599 do {
3600 current = getByte(o, offset);
3601 } while (!weakCompareAndSetByteRelease(o, offset,
3602 current, (byte) (current ^ mask)));
3603 return current;
3604 }
3605
3606 @ForceInline
3607 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3608 byte current;
3609 do {
3610 // Plain read, the value is a hint, the acquire CAS does the work
3611 current = getByte(o, offset);
3612 } while (!weakCompareAndSetByteAcquire(o, offset,
3613 current, (byte) (current ^ mask)));
3614 return current;
3615 }
3616
3617
3618 @ForceInline
3619 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3620 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3621 }
3622
3623 @ForceInline
3624 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3625 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3626 }
3627
3628 @ForceInline
3629 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3630 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3631 }
3632
3633 @ForceInline
3634 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3635 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3636 }
3637
3638 @ForceInline
3639 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3640 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3641 }
3642
3643 @ForceInline
3644 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3645 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3646 }
3647
3648 @ForceInline
3649 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3650 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3651 }
3652
3653 @ForceInline
3654 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3655 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3656 }
3657
3658 @ForceInline
3659 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3660 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3661 }
3662
3663
3664 @ForceInline
3665 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3666 short current;
3667 do {
3668 current = getShortVolatile(o, offset);
3669 } while (!weakCompareAndSetShort(o, offset,
3670 current, (short) (current | mask)));
3671 return current;
3672 }
3673
3674 @ForceInline
3675 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3676 short current;
3677 do {
3678 current = getShort(o, offset);
3679 } while (!weakCompareAndSetShortRelease(o, offset,
3680 current, (short) (current | mask)));
3681 return current;
3682 }
3683
3684 @ForceInline
3685 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3686 short current;
3687 do {
3688 // Plain read, the value is a hint, the acquire CAS does the work
3689 current = getShort(o, offset);
3690 } while (!weakCompareAndSetShortAcquire(o, offset,
3691 current, (short) (current | mask)));
3692 return current;
3693 }
3694
3695 @ForceInline
3696 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3697 short current;
3698 do {
3699 current = getShortVolatile(o, offset);
3700 } while (!weakCompareAndSetShort(o, offset,
3701 current, (short) (current & mask)));
3702 return current;
3703 }
3704
3705 @ForceInline
3706 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3707 short current;
3708 do {
3709 current = getShort(o, offset);
3710 } while (!weakCompareAndSetShortRelease(o, offset,
3711 current, (short) (current & mask)));
3712 return current;
3713 }
3714
3715 @ForceInline
3716 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3717 short current;
3718 do {
3719 // Plain read, the value is a hint, the acquire CAS does the work
3720 current = getShort(o, offset);
3721 } while (!weakCompareAndSetShortAcquire(o, offset,
3722 current, (short) (current & mask)));
3723 return current;
3724 }
3725
3726 @ForceInline
3727 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3728 short current;
3729 do {
3730 current = getShortVolatile(o, offset);
3731 } while (!weakCompareAndSetShort(o, offset,
3732 current, (short) (current ^ mask)));
3733 return current;
3734 }
3735
3736 @ForceInline
3737 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3738 short current;
3739 do {
3740 current = getShort(o, offset);
3741 } while (!weakCompareAndSetShortRelease(o, offset,
3742 current, (short) (current ^ mask)));
3743 return current;
3744 }
3745
3746 @ForceInline
3747 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3748 short current;
3749 do {
3750 // Plain read, the value is a hint, the acquire CAS does the work
3751 current = getShort(o, offset);
3752 } while (!weakCompareAndSetShortAcquire(o, offset,
3753 current, (short) (current ^ mask)));
3754 return current;
3755 }
3756
3757
3758 @ForceInline
3759 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3760 int current;
3761 do {
3762 current = getIntVolatile(o, offset);
3763 } while (!weakCompareAndSetInt(o, offset,
3764 current, current | mask));
3765 return current;
3766 }
3767
3768 @ForceInline
3769 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3770 int current;
3771 do {
3772 current = getInt(o, offset);
3773 } while (!weakCompareAndSetIntRelease(o, offset,
3774 current, current | mask));
3775 return current;
3776 }
3777
3778 @ForceInline
3779 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3780 int current;
3781 do {
3782 // Plain read, the value is a hint, the acquire CAS does the work
3783 current = getInt(o, offset);
3784 } while (!weakCompareAndSetIntAcquire(o, offset,
3785 current, current | mask));
3786 return current;
3787 }
3788
3789 /**
3790 * Atomically replaces the current value of a field or array element within
3791 * the given object with the result of bitwise AND between the current value
3792 * and mask.
3793 *
3794 * @param o object/array to update the field/element in
3795 * @param offset field/element offset
3796 * @param mask the mask value
3797 * @return the previous value
3798 * @since 9
3799 */
3800 @ForceInline
3801 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3802 int current;
3803 do {
3804 current = getIntVolatile(o, offset);
3805 } while (!weakCompareAndSetInt(o, offset,
3806 current, current & mask));
3807 return current;
3808 }
3809
3810 @ForceInline
3811 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3812 int current;
3813 do {
3814 current = getInt(o, offset);
3815 } while (!weakCompareAndSetIntRelease(o, offset,
3816 current, current & mask));
3817 return current;
3818 }
3819
3820 @ForceInline
3821 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3822 int current;
3823 do {
3824 // Plain read, the value is a hint, the acquire CAS does the work
3825 current = getInt(o, offset);
3826 } while (!weakCompareAndSetIntAcquire(o, offset,
3827 current, current & mask));
3828 return current;
3829 }
3830
3831 @ForceInline
3832 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3833 int current;
3834 do {
3835 current = getIntVolatile(o, offset);
3836 } while (!weakCompareAndSetInt(o, offset,
3837 current, current ^ mask));
3838 return current;
3839 }
3840
3841 @ForceInline
3842 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3843 int current;
3844 do {
3845 current = getInt(o, offset);
3846 } while (!weakCompareAndSetIntRelease(o, offset,
3847 current, current ^ mask));
3848 return current;
3849 }
3850
3851 @ForceInline
3852 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3853 int current;
3854 do {
3855 // Plain read, the value is a hint, the acquire CAS does the work
3856 current = getInt(o, offset);
3857 } while (!weakCompareAndSetIntAcquire(o, offset,
3858 current, current ^ mask));
3859 return current;
3860 }
3861
3862
3863 @ForceInline
3864 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3865 long current;
3866 do {
3867 current = getLongVolatile(o, offset);
3868 } while (!weakCompareAndSetLong(o, offset,
3869 current, current | mask));
3870 return current;
3871 }
3872
3873 @ForceInline
3874 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3875 long current;
3876 do {
3877 current = getLong(o, offset);
3878 } while (!weakCompareAndSetLongRelease(o, offset,
3879 current, current | mask));
3880 return current;
3881 }
3882
3883 @ForceInline
3884 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3885 long current;
3886 do {
3887 // Plain read, the value is a hint, the acquire CAS does the work
3888 current = getLong(o, offset);
3889 } while (!weakCompareAndSetLongAcquire(o, offset,
3890 current, current | mask));
3891 return current;
3892 }
3893
3894 @ForceInline
3895 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3896 long current;
3897 do {
3898 current = getLongVolatile(o, offset);
3899 } while (!weakCompareAndSetLong(o, offset,
3900 current, current & mask));
3901 return current;
3902 }
3903
3904 @ForceInline
3905 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3906 long current;
3907 do {
3908 current = getLong(o, offset);
3909 } while (!weakCompareAndSetLongRelease(o, offset,
3910 current, current & mask));
3911 return current;
3912 }
3913
3914 @ForceInline
3915 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3916 long current;
3917 do {
3918 // Plain read, the value is a hint, the acquire CAS does the work
3919 current = getLong(o, offset);
3920 } while (!weakCompareAndSetLongAcquire(o, offset,
3921 current, current & mask));
3922 return current;
3923 }
3924
3925 @ForceInline
3926 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3927 long current;
3928 do {
3929 current = getLongVolatile(o, offset);
3930 } while (!weakCompareAndSetLong(o, offset,
3931 current, current ^ mask));
3932 return current;
3933 }
3934
3935 @ForceInline
3936 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3937 long current;
3938 do {
3939 current = getLong(o, offset);
3940 } while (!weakCompareAndSetLongRelease(o, offset,
3941 current, current ^ mask));
3942 return current;
3943 }
3944
3945 @ForceInline
3946 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3947 long current;
3948 do {
3949 // Plain read, the value is a hint, the acquire CAS does the work
3950 current = getLong(o, offset);
3951 } while (!weakCompareAndSetLongAcquire(o, offset,
3952 current, current ^ mask));
3953 return current;
3954 }
3955
3956
3957
3958 /**
3959 * Ensures that loads before the fence will not be reordered with loads and
3960 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3961 *
3962 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3963 * (an "acquire fence").
3964 *
3965 * Provides a LoadLoad barrier followed by a LoadStore barrier.
3966 *
3967 * @since 1.8
3968 */
3969 @IntrinsicCandidate
3970 public final void loadFence() {
3971 // If loadFence intrinsic is not available, fall back to full fence.
3972 fullFence();
3973 }
3974
3975 /**
3976 * Ensures that loads and stores before the fence will not be reordered with
3977 * stores after the fence; a "StoreStore plus LoadStore barrier".
3978 *
3979 * Corresponds to C11 atomic_thread_fence(memory_order_release)
3980 * (a "release fence").
3981 *
3982 * Provides a StoreStore barrier followed by a LoadStore barrier.
3983 *
3984 * @since 1.8
3985 */
3986 @IntrinsicCandidate
3987 public final void storeFence() {
3988 // If storeFence intrinsic is not available, fall back to full fence.
3989 fullFence();
3990 }
3991
3992 /**
3993 * Ensures that loads and stores before the fence will not be reordered
3994 * with loads and stores after the fence. Implies the effects of both
3995 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
3996 * barrier.
3997 *
3998 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
3999 * @since 1.8
4000 */
4001 @IntrinsicCandidate
4002 public native void fullFence();
4003
4004 /**
4005 * Ensures that loads before the fence will not be reordered with
4006 * loads after the fence.
4007 *
4008 * @implNote
4009 * This method is operationally equivalent to {@link #loadFence()}.
4010 *
4011 * @since 9
4012 */
4013 public final void loadLoadFence() {
4014 loadFence();
4015 }
4016
4017 /**
4018 * Ensures that stores before the fence will not be reordered with
4019 * stores after the fence.
4020 *
4021 * @since 9
4022 */
4023 @IntrinsicCandidate
4024 public final void storeStoreFence() {
4025 // If storeStoreFence intrinsic is not available, fall back to storeFence.
4026 storeFence();
4027 }
4028
4029 /**
4030 * Throws IllegalAccessError; for use by the VM for access control
4031 * error support.
4032 * @since 1.8
4033 */
4034 private static void throwIllegalAccessError() {
4035 throw new IllegalAccessError();
4036 }
4037
4038 /**
4039 * Throws NoSuchMethodError; for use by the VM for redefinition support.
4040 * @since 13
4041 */
4042 private static void throwNoSuchMethodError() {
4043 throw new NoSuchMethodError();
4044 }
4045
4046 /**
4047 * @return Returns true if the native byte ordering of this
4048 * platform is big-endian, false if it is little-endian.
4049 */
4050 public final boolean isBigEndian() { return BIG_ENDIAN; }
4051
4052 /**
4053 * @return Returns true if this platform is capable of performing
4054 * accesses at addresses which are not aligned for the type of the
4055 * primitive type being accessed, false otherwise.
4056 */
4057 public final boolean unalignedAccess() { return UNALIGNED_ACCESS; }
4058
4059 /**
4060 * Fetches a value at some byte offset into a given Java object.
4061 * More specifically, fetches a value within the given object
4062 * <code>o</code> at the given offset, or (if <code>o</code> is
4063 * null) from the memory address whose numerical value is the
4064 * given offset. <p>
4065 *
4066 * The specification of this method is the same as {@link
4067 * #getLong(Object, long)} except that the offset does not need to
4068 * have been obtained from {@link #objectFieldOffset} on the
4069 * {@link java.lang.reflect.Field} of some Java field. The value
4070 * in memory is raw data, and need not correspond to any Java
4071 * variable. Unless <code>o</code> is null, the value accessed
4072 * must be entirely within the allocated object. The endianness
4073 * of the value in memory is the endianness of the native platform.
4074 *
4075 * <p> The read will be atomic with respect to the largest power
4076 * of two that divides the GCD of the offset and the storage size.
4077 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
4078 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
4079 * respectively. There are no other guarantees of atomicity.
4080 * <p>
4081 * 8-byte atomicity is only guaranteed on platforms on which
4082 * support atomic accesses to longs.
4083 *
4084 * @param o Java heap object in which the value resides, if any, else
4085 * null
4086 * @param offset The offset in bytes from the start of the object
4087 * @return the value fetched from the indicated object
4088 * @throws RuntimeException No defined exceptions are thrown, not even
4089 * {@link NullPointerException}
4090 * @since 9
4091 */
4092 @IntrinsicCandidate
4093 public final long getLongUnaligned(Object o, long offset) {
4094 if ((offset & 7) == 0) {
4095 return getLong(o, offset);
4096 } else if ((offset & 3) == 0) {
4097 return makeLong(getInt(o, offset),
4098 getInt(o, offset + 4));
4099 } else if ((offset & 1) == 0) {
4100 return makeLong(getShort(o, offset),
4101 getShort(o, offset + 2),
4102 getShort(o, offset + 4),
4103 getShort(o, offset + 6));
4104 } else {
4105 return makeLong(getByte(o, offset),
4106 getByte(o, offset + 1),
4107 getByte(o, offset + 2),
4108 getByte(o, offset + 3),
4109 getByte(o, offset + 4),
4110 getByte(o, offset + 5),
4111 getByte(o, offset + 6),
4112 getByte(o, offset + 7));
4113 }
4114 }
4115 /**
4116 * As {@link #getLongUnaligned(Object, long)} but with an
4117 * additional argument which specifies the endianness of the value
4118 * as stored in memory.
4119 *
4120 * @param o Java heap object in which the variable resides
4121 * @param offset The offset in bytes from the start of the object
4122 * @param bigEndian The endianness of the value
4123 * @return the value fetched from the indicated object
4124 * @since 9
4125 */
4126 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
4127 return convEndian(bigEndian, getLongUnaligned(o, offset));
4128 }
4129
4130 /** @see #getLongUnaligned(Object, long) */
4131 @IntrinsicCandidate
4132 public final int getIntUnaligned(Object o, long offset) {
4133 if ((offset & 3) == 0) {
4134 return getInt(o, offset);
4135 } else if ((offset & 1) == 0) {
4136 return makeInt(getShort(o, offset),
4137 getShort(o, offset + 2));
4138 } else {
4139 return makeInt(getByte(o, offset),
4140 getByte(o, offset + 1),
4141 getByte(o, offset + 2),
4142 getByte(o, offset + 3));
4143 }
4144 }
4145 /** @see #getLongUnaligned(Object, long, boolean) */
4146 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
4147 return convEndian(bigEndian, getIntUnaligned(o, offset));
4148 }
4149
4150 /** @see #getLongUnaligned(Object, long) */
4151 @IntrinsicCandidate
4152 public final short getShortUnaligned(Object o, long offset) {
4153 if ((offset & 1) == 0) {
4154 return getShort(o, offset);
4155 } else {
4156 return makeShort(getByte(o, offset),
4157 getByte(o, offset + 1));
4158 }
4159 }
4160 /** @see #getLongUnaligned(Object, long, boolean) */
4161 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
4162 return convEndian(bigEndian, getShortUnaligned(o, offset));
4163 }
4164
4165 /** @see #getLongUnaligned(Object, long) */
4166 @IntrinsicCandidate
4167 public final char getCharUnaligned(Object o, long offset) {
4168 if ((offset & 1) == 0) {
4169 return getChar(o, offset);
4170 } else {
4171 return (char)makeShort(getByte(o, offset),
4172 getByte(o, offset + 1));
4173 }
4174 }
4175
4176 /** @see #getLongUnaligned(Object, long, boolean) */
4177 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
4178 return convEndian(bigEndian, getCharUnaligned(o, offset));
4179 }
4180
4181 /**
4182 * Stores a value at some byte offset into a given Java object.
4183 * <p>
4184 * The specification of this method is the same as {@link
4185 * #getLong(Object, long)} except that the offset does not need to
4186 * have been obtained from {@link #objectFieldOffset} on the
4187 * {@link java.lang.reflect.Field} of some Java field. The value
4188 * in memory is raw data, and need not correspond to any Java
4189 * variable. The endianness of the value in memory is the
4190 * endianness of the native platform.
4191 * <p>
4192 * The write will be atomic with respect to the largest power of
4193 * two that divides the GCD of the offset and the storage size.
4194 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
4195 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
4196 * respectively. There are no other guarantees of atomicity.
4197 * <p>
4198 * 8-byte atomicity is only guaranteed on platforms on which
4199 * support atomic accesses to longs.
4200 *
4201 * @param o Java heap object in which the value resides, if any, else
4202 * null
4203 * @param offset The offset in bytes from the start of the object
4204 * @param x the value to store
4205 * @throws RuntimeException No defined exceptions are thrown, not even
4206 * {@link NullPointerException}
4207 * @since 9
4208 */
4209 @IntrinsicCandidate
4210 public final void putLongUnaligned(Object o, long offset, long x) {
4211 if ((offset & 7) == 0) {
4212 putLong(o, offset, x);
4213 } else if ((offset & 3) == 0) {
4214 putLongParts(o, offset,
4215 (int)(x >> 0),
4216 (int)(x >>> 32));
4217 } else if ((offset & 1) == 0) {
4218 putLongParts(o, offset,
4219 (short)(x >>> 0),
4220 (short)(x >>> 16),
4221 (short)(x >>> 32),
4222 (short)(x >>> 48));
4223 } else {
4224 putLongParts(o, offset,
4225 (byte)(x >>> 0),
4226 (byte)(x >>> 8),
4227 (byte)(x >>> 16),
4228 (byte)(x >>> 24),
4229 (byte)(x >>> 32),
4230 (byte)(x >>> 40),
4231 (byte)(x >>> 48),
4232 (byte)(x >>> 56));
4233 }
4234 }
4235
4236 /**
4237 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
4238 * argument which specifies the endianness of the value as stored in memory.
4239 * @param o Java heap object in which the value resides
4240 * @param offset The offset in bytes from the start of the object
4241 * @param x the value to store
4242 * @param bigEndian The endianness of the value
4243 * @throws RuntimeException No defined exceptions are thrown, not even
4244 * {@link NullPointerException}
4245 * @since 9
4246 */
4247 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
4248 putLongUnaligned(o, offset, convEndian(bigEndian, x));
4249 }
4250
4251 /** @see #putLongUnaligned(Object, long, long) */
4252 @IntrinsicCandidate
4253 public final void putIntUnaligned(Object o, long offset, int x) {
4254 if ((offset & 3) == 0) {
4255 putInt(o, offset, x);
4256 } else if ((offset & 1) == 0) {
4257 putIntParts(o, offset,
4258 (short)(x >> 0),
4259 (short)(x >>> 16));
4260 } else {
4261 putIntParts(o, offset,
4262 (byte)(x >>> 0),
4263 (byte)(x >>> 8),
4264 (byte)(x >>> 16),
4265 (byte)(x >>> 24));
4266 }
4267 }
4268 /** @see #putLongUnaligned(Object, long, long, boolean) */
4269 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
4270 putIntUnaligned(o, offset, convEndian(bigEndian, x));
4271 }
4272
4273 /** @see #putLongUnaligned(Object, long, long) */
4274 @IntrinsicCandidate
4275 public final void putShortUnaligned(Object o, long offset, short x) {
4276 if ((offset & 1) == 0) {
4277 putShort(o, offset, x);
4278 } else {
4279 putShortParts(o, offset,
4280 (byte)(x >>> 0),
4281 (byte)(x >>> 8));
4282 }
4283 }
4284 /** @see #putLongUnaligned(Object, long, long, boolean) */
4285 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
4286 putShortUnaligned(o, offset, convEndian(bigEndian, x));
4287 }
4288
4289 /** @see #putLongUnaligned(Object, long, long) */
4290 @IntrinsicCandidate
4291 public final void putCharUnaligned(Object o, long offset, char x) {
4292 putShortUnaligned(o, offset, (short)x);
4293 }
4294 /** @see #putLongUnaligned(Object, long, long, boolean) */
4295 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
4296 putCharUnaligned(o, offset, convEndian(bigEndian, x));
4297 }
4298
4299 private static int pickPos(int top, int pos) { return BIG_ENDIAN ? top - pos : pos; }
4300
4301 // These methods construct integers from bytes. The byte ordering
4302 // is the native endianness of this platform.
4303 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
4304 return ((toUnsignedLong(i0) << pickPos(56, 0))
4305 | (toUnsignedLong(i1) << pickPos(56, 8))
4306 | (toUnsignedLong(i2) << pickPos(56, 16))
4307 | (toUnsignedLong(i3) << pickPos(56, 24))
4308 | (toUnsignedLong(i4) << pickPos(56, 32))
4309 | (toUnsignedLong(i5) << pickPos(56, 40))
4310 | (toUnsignedLong(i6) << pickPos(56, 48))
4311 | (toUnsignedLong(i7) << pickPos(56, 56)));
4312 }
4313 private static long makeLong(short i0, short i1, short i2, short i3) {
4314 return ((toUnsignedLong(i0) << pickPos(48, 0))
4315 | (toUnsignedLong(i1) << pickPos(48, 16))
4316 | (toUnsignedLong(i2) << pickPos(48, 32))
4317 | (toUnsignedLong(i3) << pickPos(48, 48)));
4318 }
4319 private static long makeLong(int i0, int i1) {
4320 return (toUnsignedLong(i0) << pickPos(32, 0))
4321 | (toUnsignedLong(i1) << pickPos(32, 32));
4322 }
4323 private static int makeInt(short i0, short i1) {
4324 return (toUnsignedInt(i0) << pickPos(16, 0))
4325 | (toUnsignedInt(i1) << pickPos(16, 16));
4326 }
4327 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
4328 return ((toUnsignedInt(i0) << pickPos(24, 0))
4329 | (toUnsignedInt(i1) << pickPos(24, 8))
4330 | (toUnsignedInt(i2) << pickPos(24, 16))
4331 | (toUnsignedInt(i3) << pickPos(24, 24)));
4332 }
4333 private static short makeShort(byte i0, byte i1) {
4334 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
4335 | (toUnsignedInt(i1) << pickPos(8, 8)));
4336 }
4337
4338 private static byte pick(byte le, byte be) { return BIG_ENDIAN ? be : le; }
4339 private static short pick(short le, short be) { return BIG_ENDIAN ? be : le; }
4340 private static int pick(int le, int be) { return BIG_ENDIAN ? be : le; }
4341
4342 // These methods write integers to memory from smaller parts
4343 // provided by their caller. The ordering in which these parts
4344 // are written is the native endianness of this platform.
4345 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
4346 putByte(o, offset + 0, pick(i0, i7));
4347 putByte(o, offset + 1, pick(i1, i6));
4348 putByte(o, offset + 2, pick(i2, i5));
4349 putByte(o, offset + 3, pick(i3, i4));
4350 putByte(o, offset + 4, pick(i4, i3));
4351 putByte(o, offset + 5, pick(i5, i2));
4352 putByte(o, offset + 6, pick(i6, i1));
4353 putByte(o, offset + 7, pick(i7, i0));
4354 }
4355 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
4356 putShort(o, offset + 0, pick(i0, i3));
4357 putShort(o, offset + 2, pick(i1, i2));
4358 putShort(o, offset + 4, pick(i2, i1));
4359 putShort(o, offset + 6, pick(i3, i0));
4360 }
4361 private void putLongParts(Object o, long offset, int i0, int i1) {
4362 putInt(o, offset + 0, pick(i0, i1));
4363 putInt(o, offset + 4, pick(i1, i0));
4364 }
4365 private void putIntParts(Object o, long offset, short i0, short i1) {
4366 putShort(o, offset + 0, pick(i0, i1));
4367 putShort(o, offset + 2, pick(i1, i0));
4368 }
4369 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
4370 putByte(o, offset + 0, pick(i0, i3));
4371 putByte(o, offset + 1, pick(i1, i2));
4372 putByte(o, offset + 2, pick(i2, i1));
4373 putByte(o, offset + 3, pick(i3, i0));
4374 }
4375 private void putShortParts(Object o, long offset, byte i0, byte i1) {
4376 putByte(o, offset + 0, pick(i0, i1));
4377 putByte(o, offset + 1, pick(i1, i0));
4378 }
4379
4380 // Zero-extend an integer
4381 private static int toUnsignedInt(byte n) { return n & 0xff; }
4382 private static int toUnsignedInt(short n) { return n & 0xffff; }
4383 private static long toUnsignedLong(byte n) { return n & 0xffl; }
4384 private static long toUnsignedLong(short n) { return n & 0xffffl; }
4385 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
4386
4387 // Maybe byte-reverse an integer
4388 private static char convEndian(boolean big, char n) { return big == BIG_ENDIAN ? n : Character.reverseBytes(n); }
4389 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
4390 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
4391 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
4392
4393
4394
4395 private native long allocateMemory0(long bytes);
4396 private native long reallocateMemory0(long address, long bytes);
4397 private native void freeMemory0(long address);
4398 @IntrinsicCandidate
4399 private native void setMemory0(Object o, long offset, long bytes, byte value);
4400 @IntrinsicCandidate
4401 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
4402 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
4403 private native long objectFieldOffset0(Field f);
4404 private native long objectFieldOffset1(Class<?> c, String name);
4405 private native long staticFieldOffset0(Field f);
4406 private native Object staticFieldBase0(Field f);
4407 private native boolean shouldBeInitialized0(Class<?> c);
4408 private native void ensureClassInitialized0(Class<?> c);
4409 private native void notifyStrictStaticAccess0(Class<?> c, long staticFieldOffset, boolean writing);
4410 private native int arrayBaseOffset0(Class<?> arrayClass); // public version returns long to promote correct arithmetic
4411 private native int arrayBaseOffset1(Object[] array);
4412 private native int arrayIndexScale0(Class<?> arrayClass);
4413 private native int arrayIndexScale1(Object[] array);
4414 private native long getObjectSize0(Object o);
4415 private native int getLoadAverage0(double[] loadavg, int nelems);
4416
4417
4418 /**
4419 * Invokes the given direct byte buffer's cleaner, if any.
4420 *
4421 * @param directBuffer a direct byte buffer
4422 * @throws NullPointerException if {@code directBuffer} is null
4423 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
4424 * or is a {@link java.nio.Buffer#slice slice}, or is a
4425 * {@link java.nio.Buffer#duplicate duplicate}
4426 */
4427 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
4428 if (!directBuffer.isDirect())
4429 throw new IllegalArgumentException("buffer is non-direct");
4430
4431 DirectBuffer db = (DirectBuffer) directBuffer;
4432 if (db.attachment() != null)
4433 throw new IllegalArgumentException("duplicate or slice");
4434
4435 Cleaner cleaner = db.cleaner();
4436 if (cleaner != null) {
4437 cleaner.clean();
4438 }
4439 }
4440 }