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.value.ValueClass;
29 import jdk.internal.vm.annotation.AOTRuntimeSetup;
30 import jdk.internal.vm.annotation.AOTSafeClassInitializer;
31 import jdk.internal.vm.annotation.ForceInline;
32 import jdk.internal.vm.annotation.IntrinsicCandidate;
33 import sun.nio.Cleaner;
34 import sun.nio.ch.DirectBuffer;
35
36 import java.lang.reflect.Field;
37 import java.security.ProtectionDomain;
38
39 import static jdk.internal.misc.UnsafeConstants.*;
40
41 /**
42 * A collection of methods for performing low-level, unsafe operations.
43 * Although the class and all methods are public, use of this class is
44 * limited because only trusted code can obtain instances of it.
45 *
46 * <em>Note:</em> It is the responsibility of the caller to make sure
47 * arguments are checked before methods of this class are
48 * called. While some rudimentary checks are performed on the input,
49 * the checks are best effort and when performance is an overriding
50 * priority, as when methods of this class are optimized by the
51 * runtime compiler, some or all checks (if any) may be elided. Hence,
52 * the caller must not rely on the checks and corresponding
53 * exceptions!
54 *
55 * @author John R. Rose
56 * @see #getUnsafe
57 */
58 @AOTSafeClassInitializer
59 public final class Unsafe {
60
61 private static native void registerNatives();
62 static {
63 runtimeSetup();
64 }
65
66 /// BASE_OFFSET, INDEX_SCALE, and ADDRESS_SIZE fields are equivalent if the
67 /// AOT initialized heap is reused, so just register natives
68 @AOTRuntimeSetup
69 private static void runtimeSetup() {
70 registerNatives();
71 }
72
73 private Unsafe() {}
74
75 private static final Unsafe theUnsafe = new Unsafe();
76
77 /**
78 * Provides the caller with the capability of performing unsafe
79 * operations.
80 *
81 * <p>The returned {@code Unsafe} object should be carefully guarded
82 * by the caller, since it can be used to read and write data at arbitrary
83 * memory addresses. It must never be passed to untrusted code.
84 *
85 * <p>Most methods in this class are very low-level, and correspond to a
86 * small number of hardware instructions (on typical machines). Compilers
87 * are encouraged to optimize these methods accordingly.
88 *
89 * <p>Here is a suggested idiom for using unsafe operations:
90 *
91 * <pre> {@code
92 * class MyTrustedClass {
93 * private static final Unsafe unsafe = Unsafe.getUnsafe();
94 * ...
95 * private long myCountAddress = ...;
96 * public int getCount() { return unsafe.getByte(myCountAddress); }
97 * }}</pre>
98 *
99 * (It may assist compilers to make the local variable {@code final}.)
100 */
101 public static Unsafe getUnsafe() {
102 return theUnsafe;
103 }
104
105 //--- peek and poke operations
106 // (compilers should optimize these to memory ops)
107
108 // These work on object fields in the Java heap.
109 // They will not work on elements of packed arrays.
110
111 /**
112 * Fetches a value from a given Java variable.
113 * More specifically, fetches a field or array element within the given
114 * object {@code o} at the given offset, or (if {@code o} is null)
115 * from the memory address whose numerical value is the given offset.
116 * <p>
117 * The results are undefined unless one of the following cases is true:
118 * <ul>
119 * <li>The offset was obtained from {@link #objectFieldOffset} on
120 * the {@link java.lang.reflect.Field} of some Java field and the object
121 * referred to by {@code o} is of a class compatible with that
122 * field's class.
123 *
124 * <li>The offset and object reference {@code o} (either null or
125 * non-null) were both obtained via {@link #staticFieldOffset}
126 * and {@link #staticFieldBase} (respectively) from the
127 * reflective {@link Field} representation of some Java field.
128 *
129 * <li>The object referred to by {@code o} is an array, and the offset
130 * is an integer of the form {@code B+N*S}, where {@code N} is
131 * a valid index into the array, and {@code B} and {@code S} are
132 * the values obtained by {@link #arrayBaseOffset} and {@link
133 * #arrayIndexScale} (respectively) from the array's class. The value
134 * referred to is the {@code N}<em>th</em> element of the array.
135 *
136 * </ul>
137 * <p>
138 * If one of the above cases is true, the call references a specific Java
139 * variable (field or array element). However, the results are undefined
140 * if that variable is not in fact of the type returned by this method.
141 * <p>
142 * This method refers to a variable by means of two parameters, and so
143 * it provides (in effect) a <em>double-register</em> addressing mode
144 * for Java variables. When the object reference is null, this method
145 * uses its offset as an absolute address. This is similar in operation
146 * to methods such as {@link #getInt(long)}, which provide (in effect) a
147 * <em>single-register</em> addressing mode for non-Java variables.
148 * However, because Java variables may have a different layout in memory
149 * from non-Java variables, programmers should not assume that these
150 * two addressing modes are ever equivalent. Also, programmers should
151 * remember that offsets from the double-register addressing mode cannot
152 * be portably confused with longs used in the single-register addressing
153 * mode.
154 *
155 * @param o Java heap object in which the variable resides, if any, else
156 * null
157 * @param offset indication of where the variable resides in a Java heap
158 * object, if any, else a memory address locating the variable
159 * statically
160 * @return the value fetched from the indicated Java variable
161 * @throws RuntimeException No defined exceptions are thrown, not even
162 * {@link NullPointerException}
163 */
164 @IntrinsicCandidate
165 public native int getInt(Object o, long offset);
166
167 /**
168 * Stores a value into a given Java variable.
169 * <p>
170 * The first two parameters are interpreted exactly as with
171 * {@link #getInt(Object, long)} to refer to a specific
172 * Java variable (field or array element). The given value
173 * is stored into that variable.
174 * <p>
175 * The variable must be of the same type as the method
176 * parameter {@code x}.
177 *
178 * @param o Java heap object in which the variable resides, if any, else
179 * null
180 * @param offset indication of where the variable resides in a Java heap
181 * object, if any, else a memory address locating the variable
182 * statically
183 * @param x the value to store into the indicated Java variable
184 * @throws RuntimeException No defined exceptions are thrown, not even
185 * {@link NullPointerException}
186 */
187 @IntrinsicCandidate
188 public native void putInt(Object o, long offset, int x);
189
190
191 /**
192 * Returns true if the given field is flattened.
193 */
194 public boolean isFlatField(Field f) {
195 if (f == null) {
196 throw new NullPointerException();
197 }
198 return isFlatField0(f);
199 }
200
201 private native boolean isFlatField0(Object o);
202
203 /* Returns true if the given field has a null marker
204 * <p>
205 * Nullable flat fields are stored in a flattened representation
206 * and have an associated null marker to indicate if the the field value is
207 * null or the one stored with the flat representation
208 */
209
210 public boolean hasNullMarker(Field f) {
211 if (f == null) {
212 throw new NullPointerException();
213 }
214 return hasNullMarker0(f);
215 }
216
217 private native boolean hasNullMarker0(Object o);
218
219 /* Returns the offset of the null marker of the field,
220 * or -1 if the field doesn't have a null marker
221 */
222
223 public int nullMarkerOffset(Field f) {
224 if (f == null) {
225 throw new NullPointerException();
226 }
227 return nullMarkerOffset0(f);
228 }
229
230 private native int nullMarkerOffset0(Object o);
231
232 public static final int NON_FLAT_LAYOUT = 0;
233
234 /* Reports the kind of layout used for an element in the storage
235 * allocation of the given array. Do not expect to perform any logic
236 * or layout control with this value, it is just an opaque token
237 * used for performance reasons.
238 *
239 * A layout of 0 indicates this array is not flat.
240 */
241 public int arrayLayout(Object[] array) {
242 if (array == null) {
243 throw new NullPointerException();
244 }
245 return arrayLayout0(array);
246 }
247
248 private native int arrayLayout0(Object[] array);
249
250
251 /* Reports the kind of layout used for a given field in the storage
252 * allocation of its class. Do not expect to perform any logic
253 * or layout control with this value, it is just an opaque token
254 * used for performance reasons.
255 *
256 * A layout of 0 indicates this field is not flat.
257 */
258 public int fieldLayout(Field f) {
259 if (f == null) {
260 throw new NullPointerException();
261 }
262 return fieldLayout0(f);
263 }
264
265 private native int fieldLayout0(Object o);
266
267 public native Object[] newSpecialArray(Class<?> componentType,
268 int length, int layoutKind);
269
270 /**
271 * Fetches a reference value from a given Java variable.
272 * This method can return a reference to either an object or value
273 * or a null reference.
274 *
275 * @see #getInt(Object, long)
276 */
277 @IntrinsicCandidate
278 public native Object getReference(Object o, long offset);
279
280 /**
281 * Stores a reference value into a given Java variable.
282 * This method can store a reference to either an object or value
283 * or a null reference.
284 * <p>
285 * Unless the reference {@code x} being stored is either null
286 * or matches the field type, the results are undefined.
287 * If the reference {@code o} is non-null, card marks or
288 * other store barriers for that object (if the VM requires them)
289 * are updated.
290 * @see #putInt(Object, long, int)
291 */
292 @IntrinsicCandidate
293 public native void putReference(Object o, long offset, Object x);
294
295 /**
296 * Fetches a value of type {@code <V>} from a given Java variable.
297 * More specifically, fetches a field or array element within the given
298 * {@code o} object at the given offset, or (if {@code o} is null)
299 * from the memory address whose numerical value is the given offset.
300 *
301 * @param o Java heap object in which the variable resides, if any, else
302 * null
303 * @param offset indication of where the variable resides in a Java heap
304 * object, if any, else a memory address locating the variable
305 * statically
306 * @param valueType value type
307 * @param <V> the type of a value
308 * @return the value fetched from the indicated Java variable
309 * @throws RuntimeException No defined exceptions are thrown, not even
310 * {@link NullPointerException}
311 */
312 @IntrinsicCandidate
313 public native <V> V getValue(Object o, long offset, Class<?> valueType);
314
315 /**
316 * Fetches a value of type {@code <V>} from a given Java variable.
317 * More specifically, fetches a field or array element within the given
318 * {@code o} object at the given offset, or (if {@code o} is null)
319 * from the memory address whose numerical value is the given offset.
320 *
321 * @param o Java heap object in which the variable resides, if any, else
322 * null
323 * @param offset indication of where the variable resides in a Java heap
324 * object, if any, else a memory address locating the variable
325 * statically
326 * @param layoutKind opaque value used by the VM to know the layout
327 * the field or array element. This value must be retrieved with
328 * {@link #fieldLayout} or {@link #arrayLayout}.
329 * @param valueType value type
330 * @param <V> the type of a value
331 * @return the value fetched from the indicated Java variable
332 * @throws RuntimeException No defined exceptions are thrown, not even
333 * {@link NullPointerException}
334 */
335 @IntrinsicCandidate
336 public native <V> V getFlatValue(Object o, long offset, int layoutKind, Class<?> valueType);
337
338
339 /**
340 * Stores the given value into a given Java variable.
341 *
342 * Unless the reference {@code o} being stored is either null
343 * or matches the field type, the results are undefined.
344 *
345 * @param o Java heap object in which the variable resides, if any, else
346 * null
347 * @param offset indication of where the variable resides in a Java heap
348 * object, if any, else a memory address locating the variable
349 * statically
350 * @param valueType value type
351 * @param v the value to store into the indicated Java variable
352 * @param <V> the type of a value
353 * @throws RuntimeException No defined exceptions are thrown, not even
354 * {@link NullPointerException}
355 */
356 @IntrinsicCandidate
357 public native <V> void putValue(Object o, long offset, Class<?> valueType, V v);
358
359 /**
360 * Stores the given value into a given Java variable.
361 *
362 * Unless the reference {@code o} being stored is either null
363 * or matches the field type, the results are undefined.
364 *
365 * @param o Java heap object in which the variable resides, if any, else
366 * null
367 * @param offset indication of where the variable resides in a Java heap
368 * object, if any, else a memory address locating the variable
369 * statically
370 * @param layoutKind opaque value used by the VM to know the layout
371 * the field or array element. This value must be retrieved with
372 * {@link #fieldLayout} or {@link #arrayLayout}.
373 * @param valueType value type
374 * @param v the value to store into the indicated Java variable
375 * @param <V> the type of a value
376 * @throws RuntimeException No defined exceptions are thrown, not even
377 * {@link NullPointerException}
378 */
379 @IntrinsicCandidate
380 public native <V> void putFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, V v);
381
382 /**
383 * Returns an object instance with a private buffered value whose layout
384 * and contents is exactly the given value instance. The return object
385 * is in the larval state that can be updated using the unsafe put operation.
386 *
387 * @param value a value instance
388 * @param <V> the type of the given value instance
389 */
390 @IntrinsicCandidate
391 public native <V> V makePrivateBuffer(V value);
392
393 /**
394 * Exits the larval state and returns a value instance.
395 *
396 * @param value a value instance
397 * @param <V> the type of the given value instance
398 */
399 @IntrinsicCandidate
400 public native <V> V finishPrivateBuffer(V value);
401
402 /**
403 * Returns the header size of the given value type.
404 *
405 * @param valueType value type
406 * @return the header size of the value type
407 */
408 public native <V> long valueHeaderSize(Class<V> valueType);
409
410 /** @see #getInt(Object, long) */
411 @IntrinsicCandidate
412 public native boolean getBoolean(Object o, long offset);
413
414 /** @see #putInt(Object, long, int) */
415 @IntrinsicCandidate
416 public native void putBoolean(Object o, long offset, boolean x);
417
418 /** @see #getInt(Object, long) */
419 @IntrinsicCandidate
420 public native byte getByte(Object o, long offset);
421
422 /** @see #putInt(Object, long, int) */
423 @IntrinsicCandidate
424 public native void putByte(Object o, long offset, byte x);
425
426 /** @see #getInt(Object, long) */
427 @IntrinsicCandidate
428 public native short getShort(Object o, long offset);
429
430 /** @see #putInt(Object, long, int) */
431 @IntrinsicCandidate
432 public native void putShort(Object o, long offset, short x);
433
434 /** @see #getInt(Object, long) */
435 @IntrinsicCandidate
436 public native char getChar(Object o, long offset);
437
438 /** @see #putInt(Object, long, int) */
439 @IntrinsicCandidate
440 public native void putChar(Object o, long offset, char x);
441
442 /** @see #getInt(Object, long) */
443 @IntrinsicCandidate
444 public native long getLong(Object o, long offset);
445
446 /** @see #putInt(Object, long, int) */
447 @IntrinsicCandidate
448 public native void putLong(Object o, long offset, long x);
449
450 /** @see #getInt(Object, long) */
451 @IntrinsicCandidate
452 public native float getFloat(Object o, long offset);
453
454 /** @see #putInt(Object, long, int) */
455 @IntrinsicCandidate
456 public native void putFloat(Object o, long offset, float x);
457
458 /** @see #getInt(Object, long) */
459 @IntrinsicCandidate
460 public native double getDouble(Object o, long offset);
461
462 /** @see #putInt(Object, long, int) */
463 @IntrinsicCandidate
464 public native void putDouble(Object o, long offset, double x);
465
466 /**
467 * Fetches a native pointer from a given memory address. If the address is
468 * zero, or does not point into a block obtained from {@link
469 * #allocateMemory}, the results are undefined.
470 *
471 * <p>If the native pointer is less than 64 bits wide, it is extended as
472 * an unsigned number to a Java long. The pointer may be indexed by any
473 * given byte offset, simply by adding that offset (as a simple integer) to
474 * the long representing the pointer. The number of bytes actually read
475 * from the target address may be determined by consulting {@link
476 * #addressSize}.
477 *
478 * @see #allocateMemory
479 * @see #getInt(Object, long)
480 */
481 @ForceInline
482 public long getAddress(Object o, long offset) {
483 if (ADDRESS_SIZE == 4) {
484 return Integer.toUnsignedLong(getInt(o, offset));
485 } else {
486 return getLong(o, offset);
487 }
488 }
489
490 /**
491 * Stores a native pointer into a given memory address. If the address is
492 * zero, or does not point into a block obtained from {@link
493 * #allocateMemory}, the results are undefined.
494 *
495 * <p>The number of bytes actually written at the target address may be
496 * determined by consulting {@link #addressSize}.
497 *
498 * @see #allocateMemory
499 * @see #putInt(Object, long, int)
500 */
501 @ForceInline
502 public void putAddress(Object o, long offset, long x) {
503 if (ADDRESS_SIZE == 4) {
504 putInt(o, offset, (int)x);
505 } else {
506 putLong(o, offset, x);
507 }
508 }
509
510 // These read VM internal data.
511
512 /**
513 * Fetches an uncompressed reference value from a given native variable
514 * ignoring the VM's compressed references mode.
515 *
516 * @param address a memory address locating the variable
517 * @return the value fetched from the indicated native variable
518 */
519 public native Object getUncompressedObject(long address);
520
521 // These work on values in the C heap.
522
523 /**
524 * Fetches a value from a given memory address. If the address is zero, or
525 * does not point into a block obtained from {@link #allocateMemory}, the
526 * results are undefined.
527 *
528 * @see #allocateMemory
529 */
530 @ForceInline
531 public byte getByte(long address) {
532 return getByte(null, address);
533 }
534
535 /**
536 * Stores a value into a given memory address. If the address is zero, or
537 * does not point into a block obtained from {@link #allocateMemory}, the
538 * results are undefined.
539 *
540 * @see #getByte(long)
541 */
542 @ForceInline
543 public void putByte(long address, byte x) {
544 putByte(null, address, x);
545 }
546
547 /** @see #getByte(long) */
548 @ForceInline
549 public short getShort(long address) {
550 return getShort(null, address);
551 }
552
553 /** @see #putByte(long, byte) */
554 @ForceInline
555 public void putShort(long address, short x) {
556 putShort(null, address, x);
557 }
558
559 /** @see #getByte(long) */
560 @ForceInline
561 public char getChar(long address) {
562 return getChar(null, address);
563 }
564
565 /** @see #putByte(long, byte) */
566 @ForceInline
567 public void putChar(long address, char x) {
568 putChar(null, address, x);
569 }
570
571 /** @see #getByte(long) */
572 @ForceInline
573 public int getInt(long address) {
574 return getInt(null, address);
575 }
576
577 /** @see #putByte(long, byte) */
578 @ForceInline
579 public void putInt(long address, int x) {
580 putInt(null, address, x);
581 }
582
583 /** @see #getByte(long) */
584 @ForceInline
585 public long getLong(long address) {
586 return getLong(null, address);
587 }
588
589 /** @see #putByte(long, byte) */
590 @ForceInline
591 public void putLong(long address, long x) {
592 putLong(null, address, x);
593 }
594
595 /** @see #getByte(long) */
596 @ForceInline
597 public float getFloat(long address) {
598 return getFloat(null, address);
599 }
600
601 /** @see #putByte(long, byte) */
602 @ForceInline
603 public void putFloat(long address, float x) {
604 putFloat(null, address, x);
605 }
606
607 /** @see #getByte(long) */
608 @ForceInline
609 public double getDouble(long address) {
610 return getDouble(null, address);
611 }
612
613 /** @see #putByte(long, byte) */
614 @ForceInline
615 public void putDouble(long address, double x) {
616 putDouble(null, address, x);
617 }
618
619 /** @see #getAddress(Object, long) */
620 @ForceInline
621 public long getAddress(long address) {
622 return getAddress(null, address);
623 }
624
625 /** @see #putAddress(Object, long, long) */
626 @ForceInline
627 public void putAddress(long address, long x) {
628 putAddress(null, address, x);
629 }
630
631
632
633 //--- helper methods for validating various types of objects/values
634
635 /**
636 * Create an exception reflecting that some of the input was invalid
637 *
638 * <em>Note:</em> It is the responsibility of the caller to make
639 * sure arguments are checked before the methods are called. While
640 * some rudimentary checks are performed on the input, the checks
641 * are best effort and when performance is an overriding priority,
642 * as when methods of this class are optimized by the runtime
643 * compiler, some or all checks (if any) may be elided. Hence, the
644 * caller must not rely on the checks and corresponding
645 * exceptions!
646 *
647 * @return an exception object
648 */
649 private RuntimeException invalidInput() {
650 return new IllegalArgumentException();
651 }
652
653 /**
654 * Check if a value is 32-bit clean (32 MSB are all zero)
655 *
656 * @param value the 64-bit value to check
657 *
658 * @return true if the value is 32-bit clean
659 */
660 private boolean is32BitClean(long value) {
661 return value >>> 32 == 0;
662 }
663
664 /**
665 * Check the validity of a size (the equivalent of a size_t)
666 *
667 * @throws RuntimeException if the size is invalid
668 * (<em>Note:</em> after optimization, invalid inputs may
669 * go undetected, which will lead to unpredictable
670 * behavior)
671 */
672 private void checkSize(long size) {
673 if (ADDRESS_SIZE == 4) {
674 // Note: this will also check for negative sizes
675 if (!is32BitClean(size)) {
676 throw invalidInput();
677 }
678 } else if (size < 0) {
679 throw invalidInput();
680 }
681 }
682
683 /**
684 * Check the validity of a native address (the equivalent of void*)
685 *
686 * @throws RuntimeException if the address is invalid
687 * (<em>Note:</em> after optimization, invalid inputs may
688 * go undetected, which will lead to unpredictable
689 * behavior)
690 */
691 private void checkNativeAddress(long address) {
692 if (ADDRESS_SIZE == 4) {
693 // Accept both zero and sign extended pointers. A valid
694 // pointer will, after the +1 below, either have produced
695 // the value 0x0 or 0x1. Masking off the low bit allows
696 // for testing against 0.
697 if ((((address >> 32) + 1) & ~1) != 0) {
698 throw invalidInput();
699 }
700 }
701 }
702
703 /**
704 * Check the validity of an offset, relative to a base object
705 *
706 * @param o the base object
707 * @param offset the offset to check
708 *
709 * @throws RuntimeException if the size is invalid
710 * (<em>Note:</em> after optimization, invalid inputs may
711 * go undetected, which will lead to unpredictable
712 * behavior)
713 */
714 private void checkOffset(Object o, long offset) {
715 if (ADDRESS_SIZE == 4) {
716 // Note: this will also check for negative offsets
717 if (!is32BitClean(offset)) {
718 throw invalidInput();
719 }
720 } else if (offset < 0) {
721 throw invalidInput();
722 }
723 }
724
725 /**
726 * Check the validity of a double-register pointer
727 *
728 * Note: This code deliberately does *not* check for NPE for (at
729 * least) three reasons:
730 *
731 * 1) NPE is not just NULL/0 - there is a range of values all
732 * resulting in an NPE, which is not trivial to check for
733 *
734 * 2) It is the responsibility of the callers of Unsafe methods
735 * to verify the input, so throwing an exception here is not really
736 * useful - passing in a NULL pointer is a critical error and the
737 * must not expect an exception to be thrown anyway.
738 *
739 * 3) the actual operations will detect NULL pointers anyway by
740 * means of traps and signals (like SIGSEGV).
741 *
742 * @param o Java heap object, or null
743 * @param offset indication of where the variable resides in a Java heap
744 * object, if any, else a memory address locating the variable
745 * statically
746 *
747 * @throws RuntimeException if the pointer is invalid
748 * (<em>Note:</em> after optimization, invalid inputs may
749 * go undetected, which will lead to unpredictable
750 * behavior)
751 */
752 private void checkPointer(Object o, long offset) {
753 if (o == null) {
754 checkNativeAddress(offset);
755 } else {
756 checkOffset(o, offset);
757 }
758 }
759
760 /**
761 * Check if a type is a primitive array type
762 *
763 * @param c the type to check
764 *
765 * @return true if the type is a primitive array type
766 */
767 private void checkPrimitiveArray(Class<?> c) {
768 Class<?> componentType = c.getComponentType();
769 if (componentType == null || !componentType.isPrimitive()) {
770 throw invalidInput();
771 }
772 }
773
774 /**
775 * Check that a pointer is a valid primitive array type pointer
776 *
777 * Note: pointers off-heap are considered to be primitive arrays
778 *
779 * @throws RuntimeException if the pointer is invalid
780 * (<em>Note:</em> after optimization, invalid inputs may
781 * go undetected, which will lead to unpredictable
782 * behavior)
783 */
784 private void checkPrimitivePointer(Object o, long offset) {
785 checkPointer(o, offset);
786
787 if (o != null) {
788 // If on heap, it must be a primitive array
789 checkPrimitiveArray(o.getClass());
790 }
791 }
792
793
794 //--- wrappers for malloc, realloc, free:
795
796 /**
797 * Round up allocation size to a multiple of HeapWordSize.
798 */
799 private long alignToHeapWordSize(long bytes) {
800 if (bytes >= 0) {
801 return (bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1);
802 } else {
803 throw invalidInput();
804 }
805 }
806
807 /**
808 * Allocates a new block of native memory, of the given size in bytes. The
809 * contents of the memory are uninitialized; they will generally be
810 * garbage. The resulting native pointer will be zero if and only if the
811 * requested size is zero. The resulting native pointer will be aligned for
812 * all value types. Dispose of this memory by calling {@link #freeMemory}
813 * or resize it with {@link #reallocateMemory}.
814 *
815 * <em>Note:</em> It is the responsibility of the caller to make
816 * sure arguments are checked before the methods are called. While
817 * some rudimentary checks are performed on the input, the checks
818 * are best effort and when performance is an overriding priority,
819 * as when methods of this class are optimized by the runtime
820 * compiler, some or all checks (if any) may be elided. Hence, the
821 * caller must not rely on the checks and corresponding
822 * exceptions!
823 *
824 * @throws RuntimeException if the size is negative or too large
825 * for the native size_t type
826 *
827 * @throws OutOfMemoryError if the allocation is refused by the system
828 *
829 * @see #getByte(long)
830 * @see #putByte(long, byte)
831 */
832 public long allocateMemory(long bytes) {
833 bytes = alignToHeapWordSize(bytes);
834
835 allocateMemoryChecks(bytes);
836
837 if (bytes == 0) {
838 return 0;
839 }
840
841 long p = allocateMemory0(bytes);
842 if (p == 0) {
843 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
844 }
845
846 return p;
847 }
848
849 /**
850 * Validate the arguments to allocateMemory
851 *
852 * @throws RuntimeException if the arguments are invalid
853 * (<em>Note:</em> after optimization, invalid inputs may
854 * go undetected, which will lead to unpredictable
855 * behavior)
856 */
857 private void allocateMemoryChecks(long bytes) {
858 checkSize(bytes);
859 }
860
861 /**
862 * Resizes a new block of native memory, to the given size in bytes. The
863 * contents of the new block past the size of the old block are
864 * uninitialized; they will generally be garbage. The resulting native
865 * pointer will be zero if and only if the requested size is zero. The
866 * resulting native pointer will be aligned for all value types. Dispose
867 * of this memory by calling {@link #freeMemory}, or resize it with {@link
868 * #reallocateMemory}. The address passed to this method may be null, in
869 * which case an allocation will be performed.
870 *
871 * <em>Note:</em> It is the responsibility of the caller to make
872 * sure arguments are checked before the methods are called. While
873 * some rudimentary checks are performed on the input, the checks
874 * are best effort and when performance is an overriding priority,
875 * as when methods of this class are optimized by the runtime
876 * compiler, some or all checks (if any) may be elided. Hence, the
877 * caller must not rely on the checks and corresponding
878 * exceptions!
879 *
880 * @throws RuntimeException if the size is negative or too large
881 * for the native size_t type
882 *
883 * @throws OutOfMemoryError if the allocation is refused by the system
884 *
885 * @see #allocateMemory
886 */
887 public long reallocateMemory(long address, long bytes) {
888 bytes = alignToHeapWordSize(bytes);
889
890 reallocateMemoryChecks(address, bytes);
891
892 if (bytes == 0) {
893 freeMemory(address);
894 return 0;
895 }
896
897 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
898 if (p == 0) {
899 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
900 }
901
902 return p;
903 }
904
905 /**
906 * Validate the arguments to reallocateMemory
907 *
908 * @throws RuntimeException if the arguments are invalid
909 * (<em>Note:</em> after optimization, invalid inputs may
910 * go undetected, which will lead to unpredictable
911 * behavior)
912 */
913 private void reallocateMemoryChecks(long address, long bytes) {
914 checkPointer(null, address);
915 checkSize(bytes);
916 }
917
918 /**
919 * Sets all bytes in a given block of memory to a fixed value
920 * (usually zero).
921 *
922 * <p>This method determines a block's base address by means of two parameters,
923 * and so it provides (in effect) a <em>double-register</em> addressing mode,
924 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
925 * the offset supplies an absolute base address.
926 *
927 * <p>The stores are in coherent (atomic) units of a size determined
928 * by the address and length parameters. If the effective address and
929 * length are all even modulo 8, the stores take place in 'long' units.
930 * If the effective address and length are (resp.) even modulo 4 or 2,
931 * the stores take place in units of 'int' or 'short'.
932 *
933 * <em>Note:</em> It is the responsibility of the caller to make
934 * sure arguments are checked before the methods are called. While
935 * some rudimentary checks are performed on the input, the checks
936 * are best effort and when performance is an overriding priority,
937 * as when methods of this class are optimized by the runtime
938 * compiler, some or all checks (if any) may be elided. Hence, the
939 * caller must not rely on the checks and corresponding
940 * exceptions!
941 *
942 * @throws RuntimeException if any of the arguments is invalid
943 *
944 * @since 1.7
945 */
946 public void setMemory(Object o, long offset, long bytes, byte value) {
947 setMemoryChecks(o, offset, bytes, value);
948
949 if (bytes == 0) {
950 return;
951 }
952
953 setMemory0(o, offset, bytes, value);
954 }
955
956 /**
957 * Sets all bytes in a given block of memory to a fixed value
958 * (usually zero). This provides a <em>single-register</em> addressing mode,
959 * as discussed in {@link #getInt(Object,long)}.
960 *
961 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
962 */
963 public void setMemory(long address, long bytes, byte value) {
964 setMemory(null, address, bytes, value);
965 }
966
967 /**
968 * Validate the arguments to setMemory
969 *
970 * @throws RuntimeException if the arguments are invalid
971 * (<em>Note:</em> after optimization, invalid inputs may
972 * go undetected, which will lead to unpredictable
973 * behavior)
974 */
975 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
976 checkPrimitivePointer(o, offset);
977 checkSize(bytes);
978 }
979
980 /**
981 * Sets all bytes in a given block of memory to a copy of another
982 * block.
983 *
984 * <p>This method determines each block's base address by means of two parameters,
985 * and so it provides (in effect) a <em>double-register</em> addressing mode,
986 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
987 * the offset supplies an absolute base address.
988 *
989 * <p>The transfers are in coherent (atomic) units of a size determined
990 * by the address and length parameters. If the effective addresses and
991 * length are all even modulo 8, the transfer takes place in 'long' units.
992 * If the effective addresses and length are (resp.) even modulo 4 or 2,
993 * the transfer takes place in units of 'int' or 'short'.
994 *
995 * <em>Note:</em> It is the responsibility of the caller to make
996 * sure arguments are checked before the methods are called. While
997 * some rudimentary checks are performed on the input, the checks
998 * are best effort and when performance is an overriding priority,
999 * as when methods of this class are optimized by the runtime
1000 * compiler, some or all checks (if any) may be elided. Hence, the
1001 * caller must not rely on the checks and corresponding
1002 * exceptions!
1003 *
1004 * @throws RuntimeException if any of the arguments is invalid
1005 *
1006 * @since 1.7
1007 */
1008 public void copyMemory(Object srcBase, long srcOffset,
1009 Object destBase, long destOffset,
1010 long bytes) {
1011 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
1012
1013 if (bytes == 0) {
1014 return;
1015 }
1016
1017 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
1018 }
1019
1020 /**
1021 * Sets all bytes in a given block of memory to a copy of another
1022 * block. This provides a <em>single-register</em> addressing mode,
1023 * as discussed in {@link #getInt(Object,long)}.
1024 *
1025 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
1026 */
1027 public void copyMemory(long srcAddress, long destAddress, long bytes) {
1028 copyMemory(null, srcAddress, null, destAddress, bytes);
1029 }
1030
1031 /**
1032 * Validate the arguments to copyMemory
1033 *
1034 * @throws RuntimeException if any of the arguments is invalid
1035 * (<em>Note:</em> after optimization, invalid inputs may
1036 * go undetected, which will lead to unpredictable
1037 * behavior)
1038 */
1039 private void copyMemoryChecks(Object srcBase, long srcOffset,
1040 Object destBase, long destOffset,
1041 long bytes) {
1042 checkSize(bytes);
1043 checkPrimitivePointer(srcBase, srcOffset);
1044 checkPrimitivePointer(destBase, destOffset);
1045 }
1046
1047 /**
1048 * Copies all elements from one block of memory to another block,
1049 * *unconditionally* byte swapping the elements on the fly.
1050 *
1051 * <p>This method determines each block's base address by means of two parameters,
1052 * and so it provides (in effect) a <em>double-register</em> addressing mode,
1053 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
1054 * the offset supplies an absolute base address.
1055 *
1056 * <em>Note:</em> It is the responsibility of the caller to make
1057 * sure arguments are checked before the methods are called. While
1058 * some rudimentary checks are performed on the input, the checks
1059 * are best effort and when performance is an overriding priority,
1060 * as when methods of this class are optimized by the runtime
1061 * compiler, some or all checks (if any) may be elided. Hence, the
1062 * caller must not rely on the checks and corresponding
1063 * exceptions!
1064 *
1065 * @throws RuntimeException if any of the arguments is invalid
1066 *
1067 * @since 9
1068 */
1069 public void copySwapMemory(Object srcBase, long srcOffset,
1070 Object destBase, long destOffset,
1071 long bytes, long elemSize) {
1072 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
1073
1074 if (bytes == 0) {
1075 return;
1076 }
1077
1078 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
1079 }
1080
1081 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
1082 Object destBase, long destOffset,
1083 long bytes, long elemSize) {
1084 checkSize(bytes);
1085
1086 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
1087 throw invalidInput();
1088 }
1089 if (bytes % elemSize != 0) {
1090 throw invalidInput();
1091 }
1092
1093 checkPrimitivePointer(srcBase, srcOffset);
1094 checkPrimitivePointer(destBase, destOffset);
1095 }
1096
1097 /**
1098 * Copies all elements from one block of memory to another block, byte swapping the
1099 * elements on the fly.
1100 *
1101 * This provides a <em>single-register</em> addressing mode, as
1102 * discussed in {@link #getInt(Object,long)}.
1103 *
1104 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
1105 */
1106 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
1107 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
1108 }
1109
1110 /**
1111 * Disposes of a block of native memory, as obtained from {@link
1112 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
1113 * this method may be null, in which case no action is taken.
1114 *
1115 * <em>Note:</em> It is the responsibility of the caller to make
1116 * sure arguments are checked before the methods are called. While
1117 * some rudimentary checks are performed on the input, the checks
1118 * are best effort and when performance is an overriding priority,
1119 * as when methods of this class are optimized by the runtime
1120 * compiler, some or all checks (if any) may be elided. Hence, the
1121 * caller must not rely on the checks and corresponding
1122 * exceptions!
1123 *
1124 * @throws RuntimeException if any of the arguments is invalid
1125 *
1126 * @see #allocateMemory
1127 */
1128 public void freeMemory(long address) {
1129 freeMemoryChecks(address);
1130
1131 if (address == 0) {
1132 return;
1133 }
1134
1135 freeMemory0(address);
1136 }
1137
1138 /**
1139 * Validate the arguments to freeMemory
1140 *
1141 * @throws RuntimeException if the arguments are invalid
1142 * (<em>Note:</em> after optimization, invalid inputs may
1143 * go undetected, which will lead to unpredictable
1144 * behavior)
1145 */
1146 private void freeMemoryChecks(long address) {
1147 checkPointer(null, address);
1148 }
1149
1150 /**
1151 * Ensure writeback of a specified virtual memory address range
1152 * from cache to physical memory. All bytes in the address range
1153 * are guaranteed to have been written back to physical memory on
1154 * return from this call i.e. subsequently executed store
1155 * instructions are guaranteed not to be visible before the
1156 * writeback is completed.
1157 *
1158 * @param address
1159 * the lowest byte address that must be guaranteed written
1160 * back to memory. bytes at lower addresses may also be
1161 * written back.
1162 *
1163 * @param length
1164 * the length in bytes of the region starting at address
1165 * that must be guaranteed written back to memory.
1166 *
1167 * @throws RuntimeException if memory writeback is not supported
1168 * on the current hardware of if the arguments are invalid.
1169 * (<em>Note:</em> after optimization, invalid inputs may
1170 * go undetected, which will lead to unpredictable
1171 * behavior)
1172 *
1173 * @since 14
1174 */
1175
1176 public void writebackMemory(long address, long length) {
1177 checkWritebackEnabled();
1178 checkWritebackMemory(address, length);
1179
1180 // perform any required pre-writeback barrier
1181 writebackPreSync0();
1182
1183 // write back one cache line at a time
1184 long line = dataCacheLineAlignDown(address);
1185 long end = address + length;
1186 while (line < end) {
1187 writeback0(line);
1188 line += dataCacheLineFlushSize();
1189 }
1190
1191 // perform any required post-writeback barrier
1192 writebackPostSync0();
1193 }
1194
1195 /**
1196 * Validate the arguments to writebackMemory
1197 *
1198 * @throws RuntimeException if the arguments are invalid
1199 * (<em>Note:</em> after optimization, invalid inputs may
1200 * go undetected, which will lead to unpredictable
1201 * behavior)
1202 */
1203 private void checkWritebackMemory(long address, long length) {
1204 checkNativeAddress(address);
1205 checkSize(length);
1206 }
1207
1208 /**
1209 * Validate that the current hardware supports memory writeback.
1210 * (<em>Note:</em> this is a belt and braces check. Clients are
1211 * expected to test whether writeback is enabled by calling
1212 * ({@link isWritebackEnabled #isWritebackEnabled} and avoid
1213 * calling method {@link writeback #writeback} if it is disabled).
1214 *
1215 *
1216 * @throws RuntimeException if memory writeback is not supported
1217 */
1218 private void checkWritebackEnabled() {
1219 if (!isWritebackEnabled()) {
1220 throw new RuntimeException("writebackMemory not enabled!");
1221 }
1222 }
1223
1224 /**
1225 * force writeback of an individual cache line.
1226 *
1227 * @param address
1228 * the start address of the cache line to be written back
1229 */
1230 @IntrinsicCandidate
1231 private native void writeback0(long address);
1232
1233 /**
1234 * Serialize writeback operations relative to preceding memory writes.
1235 */
1236 @IntrinsicCandidate
1237 private native void writebackPreSync0();
1238
1239 /**
1240 * Serialize writeback operations relative to following memory writes.
1241 */
1242 @IntrinsicCandidate
1243 private native void writebackPostSync0();
1244
1245 //--- random queries
1246
1247 /**
1248 * This constant differs from all results that will ever be returned from
1249 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1250 * or {@link #arrayBaseOffset}.
1251 * <p>
1252 * The static type is @code long} to emphasize that long arithmetic should
1253 * always be used for offset calculations to avoid overflows.
1254 */
1255 public static final long INVALID_FIELD_OFFSET = -1;
1256
1257 /**
1258 * Reports the location of a given field in the storage allocation of its
1259 * class. Do not expect to perform any sort of arithmetic on this offset;
1260 * it is just a cookie which is passed to the unsafe heap memory accessors.
1261 *
1262 * <p>Any given field will always have the same offset and base, and no
1263 * two distinct fields of the same class will ever have the same offset
1264 * and base.
1265 *
1266 * <p>As of 1.4.1, offsets for fields are represented as long values,
1267 * although the Sun JVM does not use the most significant 32 bits.
1268 * However, JVM implementations which store static fields at absolute
1269 * addresses can use long offsets and null base pointers to express
1270 * the field locations in a form usable by {@link #getInt(Object,long)}.
1271 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1272 * must preserve all bits of static field offsets.
1273 *
1274 * @throws NullPointerException if the field is {@code null}
1275 * @throws IllegalArgumentException if the field is static
1276 * @see #getInt(Object, long)
1277 */
1278 public long objectFieldOffset(Field f) {
1279 if (f == null) {
1280 throw new NullPointerException();
1281 }
1282
1283 return objectFieldOffset0(f);
1284 }
1285
1286 /**
1287 * (For compile-time known instance fields in JDK code only) Reports the
1288 * location of the field with a given name in the storage allocation of its
1289 * class.
1290 * <p>
1291 * This API is used to avoid creating reflective Objects in Java code at
1292 * startup. This should not be used to find fields in non-trusted code.
1293 * Use the {@link #objectFieldOffset(Field) Field}-accepting version for
1294 * arbitrary fields instead.
1295 *
1296 * @throws NullPointerException if any parameter is {@code null}.
1297 * @throws InternalError if the presumably known field couldn't be found
1298 *
1299 * @see #objectFieldOffset(Field)
1300 */
1301 public long objectFieldOffset(Class<?> c, String name) {
1302 if (c == null || name == null) {
1303 throw new NullPointerException();
1304 }
1305
1306 long result = knownObjectFieldOffset0(c, name);
1307 if (result < 0) {
1308 String type = switch ((int) result) {
1309 case -2 -> "a static field";
1310 case -1 -> "not found";
1311 default -> "unknown";
1312 };
1313 throw new InternalError("Field %s.%s %s".formatted(c.getTypeName(), name, type));
1314 }
1315 return result;
1316 }
1317
1318 /**
1319 * Reports the location of a given static field, in conjunction with {@link
1320 * #staticFieldBase}.
1321 * <p>Do not expect to perform any sort of arithmetic on this offset;
1322 * it is just a cookie which is passed to the unsafe heap memory accessors.
1323 *
1324 * <p>Any given field will always have the same offset, and no two distinct
1325 * fields of the same class will ever have the same offset.
1326 *
1327 * <p>As of 1.4.1, offsets for fields are represented as long values,
1328 * although the Sun JVM does not use the most significant 32 bits.
1329 * It is hard to imagine a JVM technology which needs more than
1330 * a few bits to encode an offset within a non-array object,
1331 * However, for consistency with other methods in this class,
1332 * this method reports its result as a long value.
1333 *
1334 * @throws NullPointerException if the field is {@code null}
1335 * @throws IllegalArgumentException if the field is not static
1336 * @see #getInt(Object, long)
1337 */
1338 public long staticFieldOffset(Field f) {
1339 if (f == null) {
1340 throw new NullPointerException();
1341 }
1342
1343 return staticFieldOffset0(f);
1344 }
1345
1346 /**
1347 * Reports the location of a given static field, in conjunction with {@link
1348 * #staticFieldOffset}.
1349 * <p>Fetch the base "Object", if any, with which static fields of the
1350 * given class can be accessed via methods like {@link #getInt(Object,
1351 * long)}. This value may be null. This value may refer to an object
1352 * which is a "cookie", not guaranteed to be a real Object, and it should
1353 * not be used in any way except as argument to the get and put routines in
1354 * this class.
1355 *
1356 * @throws NullPointerException if the field is {@code null}
1357 * @throws IllegalArgumentException if the field is not static
1358 */
1359 public Object staticFieldBase(Field f) {
1360 if (f == null) {
1361 throw new NullPointerException();
1362 }
1363
1364 return staticFieldBase0(f);
1365 }
1366
1367 /**
1368 * Detects if the given class may need to be initialized. This is often
1369 * needed in conjunction with obtaining the static field base of a
1370 * class.
1371 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1372 */
1373 public boolean shouldBeInitialized(Class<?> c) {
1374 if (c == null) {
1375 throw new NullPointerException();
1376 }
1377
1378 return shouldBeInitialized0(c);
1379 }
1380
1381 /**
1382 * Ensures the given class has been initialized (see JVMS-5.5 for details).
1383 * This is often needed in conjunction with obtaining the static field base
1384 * of a class.
1385 *
1386 * The call returns when either class {@code c} is fully initialized or
1387 * class {@code c} is being initialized and the call is performed from
1388 * the initializing thread. In the latter case a subsequent call to
1389 * {@link #shouldBeInitialized} will return {@code true}.
1390 */
1391 public void ensureClassInitialized(Class<?> c) {
1392 if (c == null) {
1393 throw new NullPointerException();
1394 }
1395
1396 ensureClassInitialized0(c);
1397 }
1398
1399 /**
1400 * The reading or writing of strict static fields may require
1401 * special processing. Notify the VM that such an event is about
1402 * to happen. The VM may respond by throwing an exception, in the
1403 * case of a read of an uninitialized field. If the VM allows the
1404 * method to return normally, no further calls are needed, with
1405 * the same arguments.
1406 */
1407 public void notifyStrictStaticAccess(Class<?> c, long staticFieldOffset, boolean writing) {
1408 if (c == null) {
1409 throw new NullPointerException();
1410 }
1411 notifyStrictStaticAccess0(c, staticFieldOffset, writing);
1412 }
1413
1414 /**
1415 * Reports the offset of the first element in the storage allocation of a
1416 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1417 * for the same class, you may use that scale factor, together with this
1418 * base offset, to form new offsets to access elements of arrays of the
1419 * given class.
1420 * <p>
1421 * The return value is in the range of a {@code int}. The return type is
1422 * {@code long} to emphasize that long arithmetic should always be used
1423 * for offset calculations to avoid overflows.
1424 * <p>
1425 * This method doesn't support arrays with an element type that is
1426 * a value class, because this type of array can have multiple layouts.
1427 * For these arrays, {@code arrayInstanceBaseOffset(Object[] array)}
1428 * must be used instead.
1429 *
1430 * @see #getInt(Object, long)
1431 * @see #putInt(Object, long, int)
1432 */
1433 public long arrayBaseOffset(Class<?> arrayClass) {
1434 if (arrayClass == null) {
1435 throw new NullPointerException();
1436 }
1437
1438 return arrayBaseOffset0(arrayClass);
1439 }
1440
1441 public long arrayInstanceBaseOffset(Object[] array) {
1442 if (array == null) {
1443 throw new NullPointerException();
1444 }
1445
1446 return arrayInstanceBaseOffset0(array);
1447 }
1448
1449 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1450 public static final long ARRAY_BOOLEAN_BASE_OFFSET
1451 = theUnsafe.arrayBaseOffset(boolean[].class);
1452
1453 /** The value of {@code arrayBaseOffset(byte[].class)} */
1454 public static final long ARRAY_BYTE_BASE_OFFSET
1455 = theUnsafe.arrayBaseOffset(byte[].class);
1456
1457 /** The value of {@code arrayBaseOffset(short[].class)} */
1458 public static final long ARRAY_SHORT_BASE_OFFSET
1459 = theUnsafe.arrayBaseOffset(short[].class);
1460
1461 /** The value of {@code arrayBaseOffset(char[].class)} */
1462 public static final long ARRAY_CHAR_BASE_OFFSET
1463 = theUnsafe.arrayBaseOffset(char[].class);
1464
1465 /** The value of {@code arrayBaseOffset(int[].class)} */
1466 public static final long ARRAY_INT_BASE_OFFSET
1467 = theUnsafe.arrayBaseOffset(int[].class);
1468
1469 /** The value of {@code arrayBaseOffset(long[].class)} */
1470 public static final long ARRAY_LONG_BASE_OFFSET
1471 = theUnsafe.arrayBaseOffset(long[].class);
1472
1473 /** The value of {@code arrayBaseOffset(float[].class)} */
1474 public static final long ARRAY_FLOAT_BASE_OFFSET
1475 = theUnsafe.arrayBaseOffset(float[].class);
1476
1477 /** The value of {@code arrayBaseOffset(double[].class)} */
1478 public static final long ARRAY_DOUBLE_BASE_OFFSET
1479 = theUnsafe.arrayBaseOffset(double[].class);
1480
1481 /** The value of {@code arrayBaseOffset(Object[].class)} */
1482 public static final long ARRAY_OBJECT_BASE_OFFSET
1483 = theUnsafe.arrayBaseOffset(Object[].class);
1484
1485 /**
1486 * Reports the scale factor for addressing elements in the storage
1487 * allocation of a given array class. However, arrays of "narrow" types
1488 * will generally not work properly with accessors like {@link
1489 * #getByte(Object, long)}, so the scale factor for such classes is reported
1490 * as zero.
1491 * <p>
1492 * The computation of the actual memory offset should always use {@code
1493 * long} arithmetic to avoid overflows.
1494 * <p>
1495 * This method doesn't support arrays with an element type that is
1496 * a value class, because this type of array can have multiple layouts.
1497 * For these arrays, {@code arrayInstanceIndexScale(Object[] array)}
1498 * must be used instead.
1499 *
1500 * @see #arrayBaseOffset
1501 * @see #getInt(Object, long)
1502 * @see #putInt(Object, long, int)
1503 */
1504 public int arrayIndexScale(Class<?> arrayClass) {
1505 if (arrayClass == null) {
1506 throw new NullPointerException();
1507 }
1508
1509 return arrayIndexScale0(arrayClass);
1510 }
1511
1512 public int arrayInstanceIndexScale(Object[] array) {
1513 if (array == null) {
1514 throw new NullPointerException();
1515 }
1516
1517 return arrayInstanceIndexScale0(array);
1518 }
1519
1520 /**
1521 * Return the size of the object in the heap.
1522 * @param o an object
1523 * @return the objects's size
1524 * @since Valhalla
1525 */
1526 public long getObjectSize(Object o) {
1527 if (o == null)
1528 throw new NullPointerException();
1529 return getObjectSize0(o);
1530 }
1531
1532 /** The value of {@code arrayIndexScale(boolean[].class)} */
1533 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1534 = theUnsafe.arrayIndexScale(boolean[].class);
1535
1536 /** The value of {@code arrayIndexScale(byte[].class)} */
1537 public static final int ARRAY_BYTE_INDEX_SCALE
1538 = theUnsafe.arrayIndexScale(byte[].class);
1539
1540 /** The value of {@code arrayIndexScale(short[].class)} */
1541 public static final int ARRAY_SHORT_INDEX_SCALE
1542 = theUnsafe.arrayIndexScale(short[].class);
1543
1544 /** The value of {@code arrayIndexScale(char[].class)} */
1545 public static final int ARRAY_CHAR_INDEX_SCALE
1546 = theUnsafe.arrayIndexScale(char[].class);
1547
1548 /** The value of {@code arrayIndexScale(int[].class)} */
1549 public static final int ARRAY_INT_INDEX_SCALE
1550 = theUnsafe.arrayIndexScale(int[].class);
1551
1552 /** The value of {@code arrayIndexScale(long[].class)} */
1553 public static final int ARRAY_LONG_INDEX_SCALE
1554 = theUnsafe.arrayIndexScale(long[].class);
1555
1556 /** The value of {@code arrayIndexScale(float[].class)} */
1557 public static final int ARRAY_FLOAT_INDEX_SCALE
1558 = theUnsafe.arrayIndexScale(float[].class);
1559
1560 /** The value of {@code arrayIndexScale(double[].class)} */
1561 public static final int ARRAY_DOUBLE_INDEX_SCALE
1562 = theUnsafe.arrayIndexScale(double[].class);
1563
1564 /** The value of {@code arrayIndexScale(Object[].class)} */
1565 public static final int ARRAY_OBJECT_INDEX_SCALE
1566 = theUnsafe.arrayIndexScale(Object[].class);
1567
1568 /**
1569 * Reports the size in bytes of a native pointer, as stored via {@link
1570 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1571 * other primitive types (as stored in native memory blocks) is determined
1572 * fully by their information content.
1573 */
1574 public int addressSize() {
1575 return ADDRESS_SIZE;
1576 }
1577
1578 /** The value of {@code addressSize()} */
1579 public static final int ADDRESS_SIZE = ADDRESS_SIZE0;
1580
1581 /**
1582 * Reports the size in bytes of a native memory page (whatever that is).
1583 * This value will always be a power of two.
1584 */
1585 public int pageSize() { return PAGE_SIZE; }
1586
1587 /**
1588 * Reports the size in bytes of a data cache line written back by
1589 * the hardware cache line flush operation available to the JVM or
1590 * 0 if data cache line flushing is not enabled.
1591 */
1592 public int dataCacheLineFlushSize() { return DATA_CACHE_LINE_FLUSH_SIZE; }
1593
1594 /**
1595 * Rounds down address to a data cache line boundary as
1596 * determined by {@link #dataCacheLineFlushSize}
1597 * @return the rounded down address
1598 */
1599 public long dataCacheLineAlignDown(long address) {
1600 return (address & ~(DATA_CACHE_LINE_FLUSH_SIZE - 1));
1601 }
1602
1603 /**
1604 * Returns true if data cache line writeback
1605 */
1606 public static boolean isWritebackEnabled() { return DATA_CACHE_LINE_FLUSH_SIZE != 0; }
1607
1608 //--- random trusted operations from JNI:
1609
1610 /**
1611 * Tells the VM to define a class, without security checks. By default, the
1612 * class loader and protection domain come from the caller's class.
1613 */
1614 public Class<?> defineClass(String name, byte[] b, int off, int len,
1615 ClassLoader loader,
1616 ProtectionDomain protectionDomain) {
1617 if (b == null) {
1618 throw new NullPointerException();
1619 }
1620 if (len < 0) {
1621 throw new ArrayIndexOutOfBoundsException();
1622 }
1623
1624 return defineClass0(name, b, off, len, loader, protectionDomain);
1625 }
1626
1627 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1628 ClassLoader loader,
1629 ProtectionDomain protectionDomain);
1630
1631 /**
1632 * Allocates an instance but does not run any constructor.
1633 * Initializes the class if it has not yet been.
1634 */
1635 @IntrinsicCandidate
1636 public native Object allocateInstance(Class<?> cls)
1637 throws InstantiationException;
1638
1639 /**
1640 * Allocates an array of a given type, but does not do zeroing.
1641 * <p>
1642 * This method should only be used in the very rare cases where a high-performance code
1643 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1644 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1645 * <p>
1646 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1647 * before allowing untrusted code, or code in other threads, to observe the reference
1648 * to the newly allocated array. In addition, the publication of the array reference must be
1649 * safe according to the Java Memory Model requirements.
1650 * <p>
1651 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1652 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1653 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1654 * or issuing a {@link #storeFence} before publishing the reference.
1655 * <p>
1656 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1657 * elements that could break heap integrity.
1658 *
1659 * @param componentType array component type to allocate
1660 * @param length array size to allocate
1661 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1662 * or the length is negative
1663 */
1664 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1665 if (componentType == null) {
1666 throw new IllegalArgumentException("Component type is null");
1667 }
1668 if (!componentType.isPrimitive()) {
1669 throw new IllegalArgumentException("Component type is not primitive");
1670 }
1671 if (length < 0) {
1672 throw new IllegalArgumentException("Negative length");
1673 }
1674 return allocateUninitializedArray0(componentType, length);
1675 }
1676
1677 @IntrinsicCandidate
1678 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1679 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1680 // return the zeroed arrays.
1681 if (componentType == byte.class) return new byte[length];
1682 if (componentType == boolean.class) return new boolean[length];
1683 if (componentType == short.class) return new short[length];
1684 if (componentType == char.class) return new char[length];
1685 if (componentType == int.class) return new int[length];
1686 if (componentType == float.class) return new float[length];
1687 if (componentType == long.class) return new long[length];
1688 if (componentType == double.class) return new double[length];
1689 return null;
1690 }
1691
1692 /** Throws the exception without telling the verifier. */
1693 public native void throwException(Throwable ee);
1694
1695 /**
1696 * Atomically updates Java variable to {@code x} if it is currently
1697 * holding {@code expected}.
1698 *
1699 * <p>This operation has memory semantics of a {@code volatile} read
1700 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1701 *
1702 * @return {@code true} if successful
1703 */
1704 @IntrinsicCandidate
1705 public final native boolean compareAndSetReference(Object o, long offset,
1706 Object expected,
1707 Object x);
1708
1709 private final boolean isValueObject(Object o) {
1710 return o != null && o.getClass().isValue();
1711 }
1712
1713 /*
1714 * For value type, CAS should do substitutability test as opposed
1715 * to two pointers comparison.
1716 */
1717 @ForceInline
1718 public final <V> boolean compareAndSetReference(Object o, long offset,
1719 Class<?> type,
1720 V expected,
1721 V x) {
1722 if (type.isValue() || isValueObject(expected)) {
1723 while (true) {
1724 Object witness = getReferenceVolatile(o, offset);
1725 if (witness != expected) {
1726 return false;
1727 }
1728 if (compareAndSetReference(o, offset, witness, x)) {
1729 return true;
1730 }
1731 }
1732 } else {
1733 return compareAndSetReference(o, offset, expected, x);
1734 }
1735 }
1736
1737 @ForceInline
1738 public final <V> boolean compareAndSetFlatValue(Object o, long offset,
1739 int layout,
1740 Class<?> valueType,
1741 V expected,
1742 V x) {
1743 while (true) {
1744 Object witness = getFlatValueVolatile(o, offset, layout, valueType);
1745 if (witness != expected) {
1746 return false;
1747 }
1748 if (compareAndSetFlatValueAsBytes(o, offset, layout, valueType, witness, x)) {
1749 return true;
1750 }
1751 }
1752 }
1753
1754 @IntrinsicCandidate
1755 public final native Object compareAndExchangeReference(Object o, long offset,
1756 Object expected,
1757 Object x);
1758
1759 @ForceInline
1760 public final <V> Object compareAndExchangeReference(Object o, long offset,
1761 Class<?> valueType,
1762 V expected,
1763 V x) {
1764 if (valueType.isValue() || isValueObject(expected)) {
1765 while (true) {
1766 Object witness = getReferenceVolatile(o, offset);
1767 if (witness != expected) {
1768 return witness;
1769 }
1770 if (compareAndSetReference(o, offset, witness, x)) {
1771 return witness;
1772 }
1773 }
1774 } else {
1775 return compareAndExchangeReference(o, offset, expected, x);
1776 }
1777 }
1778
1779 @ForceInline
1780 public final <V> Object compareAndExchangeFlatValue(Object o, long offset,
1781 int layout,
1782 Class<?> valueType,
1783 V expected,
1784 V x) {
1785 while (true) {
1786 Object witness = getFlatValueVolatile(o, offset, layout, valueType);
1787 if (witness != expected) {
1788 return witness;
1789 }
1790 if (compareAndSetFlatValueAsBytes(o, offset, layout, valueType, witness, x)) {
1791 return witness;
1792 }
1793 }
1794 }
1795
1796 @IntrinsicCandidate
1797 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1798 Object expected,
1799 Object x) {
1800 return compareAndExchangeReference(o, offset, expected, x);
1801 }
1802
1803 public final <V> Object compareAndExchangeReferenceAcquire(Object o, long offset,
1804 Class<?> valueType,
1805 V expected,
1806 V x) {
1807 return compareAndExchangeReference(o, offset, valueType, expected, x);
1808 }
1809
1810 @ForceInline
1811 public final <V> Object compareAndExchangeFlatValueAcquire(Object o, long offset,
1812 int layout,
1813 Class<?> valueType,
1814 V expected,
1815 V x) {
1816 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1817 }
1818
1819 @IntrinsicCandidate
1820 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1821 Object expected,
1822 Object x) {
1823 return compareAndExchangeReference(o, offset, expected, x);
1824 }
1825
1826 public final <V> Object compareAndExchangeReferenceRelease(Object o, long offset,
1827 Class<?> valueType,
1828 V expected,
1829 V x) {
1830 return compareAndExchangeReference(o, offset, valueType, expected, x);
1831 }
1832
1833 @ForceInline
1834 public final <V> Object compareAndExchangeFlatValueRelease(Object o, long offset,
1835 int layout,
1836 Class<?> valueType,
1837 V expected,
1838 V x) {
1839 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1840 }
1841
1842 @IntrinsicCandidate
1843 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1844 Object expected,
1845 Object x) {
1846 return compareAndSetReference(o, offset, expected, x);
1847 }
1848
1849 public final <V> boolean weakCompareAndSetReferencePlain(Object o, long offset,
1850 Class<?> valueType,
1851 V expected,
1852 V x) {
1853 if (valueType.isValue() || isValueObject(expected)) {
1854 return compareAndSetReference(o, offset, valueType, expected, x);
1855 } else {
1856 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1857 }
1858 }
1859
1860 @ForceInline
1861 public final <V> boolean weakCompareAndSetFlatValuePlain(Object o, long offset,
1862 int layout,
1863 Class<?> valueType,
1864 V expected,
1865 V x) {
1866 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1867 }
1868
1869 @IntrinsicCandidate
1870 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1871 Object expected,
1872 Object x) {
1873 return compareAndSetReference(o, offset, expected, x);
1874 }
1875
1876 public final <V> boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1877 Class<?> valueType,
1878 V expected,
1879 V x) {
1880 if (valueType.isValue() || isValueObject(expected)) {
1881 return compareAndSetReference(o, offset, valueType, expected, x);
1882 } else {
1883 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1884 }
1885 }
1886
1887 @ForceInline
1888 public final <V> boolean weakCompareAndSetFlatValueAcquire(Object o, long offset,
1889 int layout,
1890 Class<?> valueType,
1891 V expected,
1892 V x) {
1893 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1894 }
1895
1896 @IntrinsicCandidate
1897 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1898 Object expected,
1899 Object x) {
1900 return compareAndSetReference(o, offset, expected, x);
1901 }
1902
1903 public final <V> boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1904 Class<?> valueType,
1905 V expected,
1906 V x) {
1907 if (valueType.isValue() || isValueObject(expected)) {
1908 return compareAndSetReference(o, offset, valueType, expected, x);
1909 } else {
1910 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1911 }
1912 }
1913
1914 @ForceInline
1915 public final <V> boolean weakCompareAndSetFlatValueRelease(Object o, long offset,
1916 int layout,
1917 Class<?> valueType,
1918 V expected,
1919 V x) {
1920 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1921 }
1922
1923 @IntrinsicCandidate
1924 public final boolean weakCompareAndSetReference(Object o, long offset,
1925 Object expected,
1926 Object x) {
1927 return compareAndSetReference(o, offset, expected, x);
1928 }
1929
1930 public final <V> boolean weakCompareAndSetReference(Object o, long offset,
1931 Class<?> valueType,
1932 V expected,
1933 V x) {
1934 if (valueType.isValue() || isValueObject(expected)) {
1935 return compareAndSetReference(o, offset, valueType, expected, x);
1936 } else {
1937 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1938 }
1939 }
1940
1941 @ForceInline
1942 public final <V> boolean weakCompareAndSetFlatValue(Object o, long offset,
1943 int layout,
1944 Class<?> valueType,
1945 V expected,
1946 V x) {
1947 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1948 }
1949
1950 /**
1951 * Atomically updates Java variable to {@code x} if it is currently
1952 * holding {@code expected}.
1953 *
1954 * <p>This operation has memory semantics of a {@code volatile} read
1955 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1956 *
1957 * @return {@code true} if successful
1958 */
1959 @IntrinsicCandidate
1960 public final native boolean compareAndSetInt(Object o, long offset,
1961 int expected,
1962 int x);
1963
1964 @IntrinsicCandidate
1965 public final native int compareAndExchangeInt(Object o, long offset,
1966 int expected,
1967 int x);
1968
1969 @IntrinsicCandidate
1970 public final int compareAndExchangeIntAcquire(Object o, long offset,
1971 int expected,
1972 int x) {
1973 return compareAndExchangeInt(o, offset, expected, x);
1974 }
1975
1976 @IntrinsicCandidate
1977 public final int compareAndExchangeIntRelease(Object o, long offset,
1978 int expected,
1979 int x) {
1980 return compareAndExchangeInt(o, offset, expected, x);
1981 }
1982
1983 @IntrinsicCandidate
1984 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1985 int expected,
1986 int x) {
1987 return compareAndSetInt(o, offset, expected, x);
1988 }
1989
1990 @IntrinsicCandidate
1991 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1992 int expected,
1993 int x) {
1994 return compareAndSetInt(o, offset, expected, x);
1995 }
1996
1997 @IntrinsicCandidate
1998 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1999 int expected,
2000 int x) {
2001 return compareAndSetInt(o, offset, expected, x);
2002 }
2003
2004 @IntrinsicCandidate
2005 public final boolean weakCompareAndSetInt(Object o, long offset,
2006 int expected,
2007 int x) {
2008 return compareAndSetInt(o, offset, expected, x);
2009 }
2010
2011 @IntrinsicCandidate
2012 public final byte compareAndExchangeByte(Object o, long offset,
2013 byte expected,
2014 byte x) {
2015 long wordOffset = offset & ~3;
2016 int shift = (int) (offset & 3) << 3;
2017 if (BIG_ENDIAN) {
2018 shift = 24 - shift;
2019 }
2020 int mask = 0xFF << shift;
2021 int maskedExpected = (expected & 0xFF) << shift;
2022 int maskedX = (x & 0xFF) << shift;
2023 int fullWord;
2024 do {
2025 fullWord = getIntVolatile(o, wordOffset);
2026 if ((fullWord & mask) != maskedExpected)
2027 return (byte) ((fullWord & mask) >> shift);
2028 } while (!weakCompareAndSetInt(o, wordOffset,
2029 fullWord, (fullWord & ~mask) | maskedX));
2030 return expected;
2031 }
2032
2033 @IntrinsicCandidate
2034 public final boolean compareAndSetByte(Object o, long offset,
2035 byte expected,
2036 byte x) {
2037 return compareAndExchangeByte(o, offset, expected, x) == expected;
2038 }
2039
2040 @IntrinsicCandidate
2041 public final boolean weakCompareAndSetByte(Object o, long offset,
2042 byte expected,
2043 byte x) {
2044 return compareAndSetByte(o, offset, expected, x);
2045 }
2046
2047 @IntrinsicCandidate
2048 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
2049 byte expected,
2050 byte x) {
2051 return weakCompareAndSetByte(o, offset, expected, x);
2052 }
2053
2054 @IntrinsicCandidate
2055 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
2056 byte expected,
2057 byte x) {
2058 return weakCompareAndSetByte(o, offset, expected, x);
2059 }
2060
2061 @IntrinsicCandidate
2062 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
2063 byte expected,
2064 byte x) {
2065 return weakCompareAndSetByte(o, offset, expected, x);
2066 }
2067
2068 @IntrinsicCandidate
2069 public final byte compareAndExchangeByteAcquire(Object o, long offset,
2070 byte expected,
2071 byte x) {
2072 return compareAndExchangeByte(o, offset, expected, x);
2073 }
2074
2075 @IntrinsicCandidate
2076 public final byte compareAndExchangeByteRelease(Object o, long offset,
2077 byte expected,
2078 byte x) {
2079 return compareAndExchangeByte(o, offset, expected, x);
2080 }
2081
2082 @IntrinsicCandidate
2083 public final short compareAndExchangeShort(Object o, long offset,
2084 short expected,
2085 short x) {
2086 if ((offset & 3) == 3) {
2087 throw new IllegalArgumentException("Update spans the word, not supported");
2088 }
2089 long wordOffset = offset & ~3;
2090 int shift = (int) (offset & 3) << 3;
2091 if (BIG_ENDIAN) {
2092 shift = 16 - shift;
2093 }
2094 int mask = 0xFFFF << shift;
2095 int maskedExpected = (expected & 0xFFFF) << shift;
2096 int maskedX = (x & 0xFFFF) << shift;
2097 int fullWord;
2098 do {
2099 fullWord = getIntVolatile(o, wordOffset);
2100 if ((fullWord & mask) != maskedExpected) {
2101 return (short) ((fullWord & mask) >> shift);
2102 }
2103 } while (!weakCompareAndSetInt(o, wordOffset,
2104 fullWord, (fullWord & ~mask) | maskedX));
2105 return expected;
2106 }
2107
2108 @IntrinsicCandidate
2109 public final boolean compareAndSetShort(Object o, long offset,
2110 short expected,
2111 short x) {
2112 return compareAndExchangeShort(o, offset, expected, x) == expected;
2113 }
2114
2115 @IntrinsicCandidate
2116 public final boolean weakCompareAndSetShort(Object o, long offset,
2117 short expected,
2118 short x) {
2119 return compareAndSetShort(o, offset, expected, x);
2120 }
2121
2122 @IntrinsicCandidate
2123 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
2124 short expected,
2125 short x) {
2126 return weakCompareAndSetShort(o, offset, expected, x);
2127 }
2128
2129 @IntrinsicCandidate
2130 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
2131 short expected,
2132 short x) {
2133 return weakCompareAndSetShort(o, offset, expected, x);
2134 }
2135
2136 @IntrinsicCandidate
2137 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
2138 short expected,
2139 short x) {
2140 return weakCompareAndSetShort(o, offset, expected, x);
2141 }
2142
2143
2144 @IntrinsicCandidate
2145 public final short compareAndExchangeShortAcquire(Object o, long offset,
2146 short expected,
2147 short x) {
2148 return compareAndExchangeShort(o, offset, expected, x);
2149 }
2150
2151 @IntrinsicCandidate
2152 public final short compareAndExchangeShortRelease(Object o, long offset,
2153 short expected,
2154 short x) {
2155 return compareAndExchangeShort(o, offset, expected, x);
2156 }
2157
2158 @ForceInline
2159 private char s2c(short s) {
2160 return (char) s;
2161 }
2162
2163 @ForceInline
2164 private short c2s(char s) {
2165 return (short) s;
2166 }
2167
2168 @ForceInline
2169 public final boolean compareAndSetChar(Object o, long offset,
2170 char expected,
2171 char x) {
2172 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
2173 }
2174
2175 @ForceInline
2176 public final char compareAndExchangeChar(Object o, long offset,
2177 char expected,
2178 char x) {
2179 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
2180 }
2181
2182 @ForceInline
2183 public final char compareAndExchangeCharAcquire(Object o, long offset,
2184 char expected,
2185 char x) {
2186 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
2187 }
2188
2189 @ForceInline
2190 public final char compareAndExchangeCharRelease(Object o, long offset,
2191 char expected,
2192 char x) {
2193 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
2194 }
2195
2196 @ForceInline
2197 public final boolean weakCompareAndSetChar(Object o, long offset,
2198 char expected,
2199 char x) {
2200 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
2201 }
2202
2203 @ForceInline
2204 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
2205 char expected,
2206 char x) {
2207 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
2208 }
2209
2210 @ForceInline
2211 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
2212 char expected,
2213 char x) {
2214 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
2215 }
2216
2217 @ForceInline
2218 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
2219 char expected,
2220 char x) {
2221 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
2222 }
2223
2224 /**
2225 * The JVM converts integral values to boolean values using two
2226 * different conventions, byte testing against zero and truncation
2227 * to least-significant bit.
2228 *
2229 * <p>The JNI documents specify that, at least for returning
2230 * values from native methods, a Java boolean value is converted
2231 * to the value-set 0..1 by first truncating to a byte (0..255 or
2232 * maybe -128..127) and then testing against zero. Thus, Java
2233 * booleans in non-Java data structures are by convention
2234 * represented as 8-bit containers containing either zero (for
2235 * false) or any non-zero value (for true).
2236 *
2237 * <p>Java booleans in the heap are also stored in bytes, but are
2238 * strongly normalized to the value-set 0..1 (i.e., they are
2239 * truncated to the least-significant bit).
2240 *
2241 * <p>The main reason for having different conventions for
2242 * conversion is performance: Truncation to the least-significant
2243 * bit can be usually implemented with fewer (machine)
2244 * instructions than byte testing against zero.
2245 *
2246 * <p>A number of Unsafe methods load boolean values from the heap
2247 * as bytes. Unsafe converts those values according to the JNI
2248 * rules (i.e, using the "testing against zero" convention). The
2249 * method {@code byte2bool} implements that conversion.
2250 *
2251 * @param b the byte to be converted to boolean
2252 * @return the result of the conversion
2253 */
2254 @ForceInline
2255 private boolean byte2bool(byte b) {
2256 return b != 0;
2257 }
2258
2259 /**
2260 * Convert a boolean value to a byte. The return value is strongly
2261 * normalized to the value-set 0..1 (i.e., the value is truncated
2262 * to the least-significant bit). See {@link #byte2bool(byte)} for
2263 * more details on conversion conventions.
2264 *
2265 * @param b the boolean to be converted to byte (and then normalized)
2266 * @return the result of the conversion
2267 */
2268 @ForceInline
2269 private byte bool2byte(boolean b) {
2270 return b ? (byte)1 : (byte)0;
2271 }
2272
2273 @ForceInline
2274 public final boolean compareAndSetBoolean(Object o, long offset,
2275 boolean expected,
2276 boolean x) {
2277 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
2278 }
2279
2280 @ForceInline
2281 public final boolean compareAndExchangeBoolean(Object o, long offset,
2282 boolean expected,
2283 boolean x) {
2284 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
2285 }
2286
2287 @ForceInline
2288 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
2289 boolean expected,
2290 boolean x) {
2291 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
2292 }
2293
2294 @ForceInline
2295 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
2296 boolean expected,
2297 boolean x) {
2298 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
2299 }
2300
2301 @ForceInline
2302 public final boolean weakCompareAndSetBoolean(Object o, long offset,
2303 boolean expected,
2304 boolean x) {
2305 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
2306 }
2307
2308 @ForceInline
2309 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
2310 boolean expected,
2311 boolean x) {
2312 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
2313 }
2314
2315 @ForceInline
2316 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
2317 boolean expected,
2318 boolean x) {
2319 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
2320 }
2321
2322 @ForceInline
2323 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
2324 boolean expected,
2325 boolean x) {
2326 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
2327 }
2328
2329 /**
2330 * Atomically updates Java variable to {@code x} if it is currently
2331 * holding {@code expected}.
2332 *
2333 * <p>This operation has memory semantics of a {@code volatile} read
2334 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2335 *
2336 * @return {@code true} if successful
2337 */
2338 @ForceInline
2339 public final boolean compareAndSetFloat(Object o, long offset,
2340 float expected,
2341 float x) {
2342 return compareAndSetInt(o, offset,
2343 Float.floatToRawIntBits(expected),
2344 Float.floatToRawIntBits(x));
2345 }
2346
2347 @ForceInline
2348 public final float compareAndExchangeFloat(Object o, long offset,
2349 float expected,
2350 float x) {
2351 int w = compareAndExchangeInt(o, offset,
2352 Float.floatToRawIntBits(expected),
2353 Float.floatToRawIntBits(x));
2354 return Float.intBitsToFloat(w);
2355 }
2356
2357 @ForceInline
2358 public final float compareAndExchangeFloatAcquire(Object o, long offset,
2359 float expected,
2360 float x) {
2361 int w = compareAndExchangeIntAcquire(o, offset,
2362 Float.floatToRawIntBits(expected),
2363 Float.floatToRawIntBits(x));
2364 return Float.intBitsToFloat(w);
2365 }
2366
2367 @ForceInline
2368 public final float compareAndExchangeFloatRelease(Object o, long offset,
2369 float expected,
2370 float x) {
2371 int w = compareAndExchangeIntRelease(o, offset,
2372 Float.floatToRawIntBits(expected),
2373 Float.floatToRawIntBits(x));
2374 return Float.intBitsToFloat(w);
2375 }
2376
2377 @ForceInline
2378 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
2379 float expected,
2380 float x) {
2381 return weakCompareAndSetIntPlain(o, offset,
2382 Float.floatToRawIntBits(expected),
2383 Float.floatToRawIntBits(x));
2384 }
2385
2386 @ForceInline
2387 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
2388 float expected,
2389 float x) {
2390 return weakCompareAndSetIntAcquire(o, offset,
2391 Float.floatToRawIntBits(expected),
2392 Float.floatToRawIntBits(x));
2393 }
2394
2395 @ForceInline
2396 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
2397 float expected,
2398 float x) {
2399 return weakCompareAndSetIntRelease(o, offset,
2400 Float.floatToRawIntBits(expected),
2401 Float.floatToRawIntBits(x));
2402 }
2403
2404 @ForceInline
2405 public final boolean weakCompareAndSetFloat(Object o, long offset,
2406 float expected,
2407 float x) {
2408 return weakCompareAndSetInt(o, offset,
2409 Float.floatToRawIntBits(expected),
2410 Float.floatToRawIntBits(x));
2411 }
2412
2413 /**
2414 * Atomically updates Java variable to {@code x} if it is currently
2415 * holding {@code expected}.
2416 *
2417 * <p>This operation has memory semantics of a {@code volatile} read
2418 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2419 *
2420 * @return {@code true} if successful
2421 */
2422 @ForceInline
2423 public final boolean compareAndSetDouble(Object o, long offset,
2424 double expected,
2425 double x) {
2426 return compareAndSetLong(o, offset,
2427 Double.doubleToRawLongBits(expected),
2428 Double.doubleToRawLongBits(x));
2429 }
2430
2431 @ForceInline
2432 public final double compareAndExchangeDouble(Object o, long offset,
2433 double expected,
2434 double x) {
2435 long w = compareAndExchangeLong(o, offset,
2436 Double.doubleToRawLongBits(expected),
2437 Double.doubleToRawLongBits(x));
2438 return Double.longBitsToDouble(w);
2439 }
2440
2441 @ForceInline
2442 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
2443 double expected,
2444 double x) {
2445 long w = compareAndExchangeLongAcquire(o, offset,
2446 Double.doubleToRawLongBits(expected),
2447 Double.doubleToRawLongBits(x));
2448 return Double.longBitsToDouble(w);
2449 }
2450
2451 @ForceInline
2452 public final double compareAndExchangeDoubleRelease(Object o, long offset,
2453 double expected,
2454 double x) {
2455 long w = compareAndExchangeLongRelease(o, offset,
2456 Double.doubleToRawLongBits(expected),
2457 Double.doubleToRawLongBits(x));
2458 return Double.longBitsToDouble(w);
2459 }
2460
2461 @ForceInline
2462 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
2463 double expected,
2464 double x) {
2465 return weakCompareAndSetLongPlain(o, offset,
2466 Double.doubleToRawLongBits(expected),
2467 Double.doubleToRawLongBits(x));
2468 }
2469
2470 @ForceInline
2471 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
2472 double expected,
2473 double x) {
2474 return weakCompareAndSetLongAcquire(o, offset,
2475 Double.doubleToRawLongBits(expected),
2476 Double.doubleToRawLongBits(x));
2477 }
2478
2479 @ForceInline
2480 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
2481 double expected,
2482 double x) {
2483 return weakCompareAndSetLongRelease(o, offset,
2484 Double.doubleToRawLongBits(expected),
2485 Double.doubleToRawLongBits(x));
2486 }
2487
2488 @ForceInline
2489 public final boolean weakCompareAndSetDouble(Object o, long offset,
2490 double expected,
2491 double x) {
2492 return weakCompareAndSetLong(o, offset,
2493 Double.doubleToRawLongBits(expected),
2494 Double.doubleToRawLongBits(x));
2495 }
2496
2497 /**
2498 * Atomically updates Java variable to {@code x} if it is currently
2499 * holding {@code expected}.
2500 *
2501 * <p>This operation has memory semantics of a {@code volatile} read
2502 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2503 *
2504 * @return {@code true} if successful
2505 */
2506 @IntrinsicCandidate
2507 public final native boolean compareAndSetLong(Object o, long offset,
2508 long expected,
2509 long x);
2510
2511 @IntrinsicCandidate
2512 public final native long compareAndExchangeLong(Object o, long offset,
2513 long expected,
2514 long x);
2515
2516 @IntrinsicCandidate
2517 public final long compareAndExchangeLongAcquire(Object o, long offset,
2518 long expected,
2519 long x) {
2520 return compareAndExchangeLong(o, offset, expected, x);
2521 }
2522
2523 @IntrinsicCandidate
2524 public final long compareAndExchangeLongRelease(Object o, long offset,
2525 long expected,
2526 long x) {
2527 return compareAndExchangeLong(o, offset, expected, x);
2528 }
2529
2530 @IntrinsicCandidate
2531 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2532 long expected,
2533 long x) {
2534 return compareAndSetLong(o, offset, expected, x);
2535 }
2536
2537 @IntrinsicCandidate
2538 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2539 long expected,
2540 long x) {
2541 return compareAndSetLong(o, offset, expected, x);
2542 }
2543
2544 @IntrinsicCandidate
2545 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2546 long expected,
2547 long x) {
2548 return compareAndSetLong(o, offset, expected, x);
2549 }
2550
2551 @IntrinsicCandidate
2552 public final boolean weakCompareAndSetLong(Object o, long offset,
2553 long expected,
2554 long x) {
2555 return compareAndSetLong(o, offset, expected, x);
2556 }
2557
2558 /**
2559 * Fetches a reference value from a given Java variable, with volatile
2560 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2561 */
2562 @IntrinsicCandidate
2563 public native Object getReferenceVolatile(Object o, long offset);
2564
2565 @ForceInline
2566 public final <V> Object getFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType) {
2567 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2568 Object res = getFlatValue(o, offset, layout, valueType);
2569 fullFence();
2570 return res;
2571 }
2572
2573 /**
2574 * Stores a reference value into a given Java variable, with
2575 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2576 */
2577 @IntrinsicCandidate
2578 public native void putReferenceVolatile(Object o, long offset, Object x);
2579
2580 @ForceInline
2581 public final <V> void putFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType, V x) {
2582 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2583 putFlatValueRelease(o, offset, layout, valueType, x);
2584 fullFence();
2585 }
2586
2587 /** Volatile version of {@link #getInt(Object, long)} */
2588 @IntrinsicCandidate
2589 public native int getIntVolatile(Object o, long offset);
2590
2591 /** Volatile version of {@link #putInt(Object, long, int)} */
2592 @IntrinsicCandidate
2593 public native void putIntVolatile(Object o, long offset, int x);
2594
2595 /** Volatile version of {@link #getBoolean(Object, long)} */
2596 @IntrinsicCandidate
2597 public native boolean getBooleanVolatile(Object o, long offset);
2598
2599 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2600 @IntrinsicCandidate
2601 public native void putBooleanVolatile(Object o, long offset, boolean x);
2602
2603 /** Volatile version of {@link #getByte(Object, long)} */
2604 @IntrinsicCandidate
2605 public native byte getByteVolatile(Object o, long offset);
2606
2607 /** Volatile version of {@link #putByte(Object, long, byte)} */
2608 @IntrinsicCandidate
2609 public native void putByteVolatile(Object o, long offset, byte x);
2610
2611 /** Volatile version of {@link #getShort(Object, long)} */
2612 @IntrinsicCandidate
2613 public native short getShortVolatile(Object o, long offset);
2614
2615 /** Volatile version of {@link #putShort(Object, long, short)} */
2616 @IntrinsicCandidate
2617 public native void putShortVolatile(Object o, long offset, short x);
2618
2619 /** Volatile version of {@link #getChar(Object, long)} */
2620 @IntrinsicCandidate
2621 public native char getCharVolatile(Object o, long offset);
2622
2623 /** Volatile version of {@link #putChar(Object, long, char)} */
2624 @IntrinsicCandidate
2625 public native void putCharVolatile(Object o, long offset, char x);
2626
2627 /** Volatile version of {@link #getLong(Object, long)} */
2628 @IntrinsicCandidate
2629 public native long getLongVolatile(Object o, long offset);
2630
2631 /** Volatile version of {@link #putLong(Object, long, long)} */
2632 @IntrinsicCandidate
2633 public native void putLongVolatile(Object o, long offset, long x);
2634
2635 /** Volatile version of {@link #getFloat(Object, long)} */
2636 @IntrinsicCandidate
2637 public native float getFloatVolatile(Object o, long offset);
2638
2639 /** Volatile version of {@link #putFloat(Object, long, float)} */
2640 @IntrinsicCandidate
2641 public native void putFloatVolatile(Object o, long offset, float x);
2642
2643 /** Volatile version of {@link #getDouble(Object, long)} */
2644 @IntrinsicCandidate
2645 public native double getDoubleVolatile(Object o, long offset);
2646
2647 /** Volatile version of {@link #putDouble(Object, long, double)} */
2648 @IntrinsicCandidate
2649 public native void putDoubleVolatile(Object o, long offset, double x);
2650
2651
2652
2653 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2654 @IntrinsicCandidate
2655 public final Object getReferenceAcquire(Object o, long offset) {
2656 return getReferenceVolatile(o, offset);
2657 }
2658
2659 @ForceInline
2660 public final <V> Object getFlatValueAcquire(Object o, long offset, int layout, Class<?> valueType) {
2661 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2662 Object res = getFlatValue(o, offset, layout, valueType);
2663 loadFence();
2664 return res;
2665 }
2666
2667 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2668 @IntrinsicCandidate
2669 public final boolean getBooleanAcquire(Object o, long offset) {
2670 return getBooleanVolatile(o, offset);
2671 }
2672
2673 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2674 @IntrinsicCandidate
2675 public final byte getByteAcquire(Object o, long offset) {
2676 return getByteVolatile(o, offset);
2677 }
2678
2679 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2680 @IntrinsicCandidate
2681 public final short getShortAcquire(Object o, long offset) {
2682 return getShortVolatile(o, offset);
2683 }
2684
2685 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2686 @IntrinsicCandidate
2687 public final char getCharAcquire(Object o, long offset) {
2688 return getCharVolatile(o, offset);
2689 }
2690
2691 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2692 @IntrinsicCandidate
2693 public final int getIntAcquire(Object o, long offset) {
2694 return getIntVolatile(o, offset);
2695 }
2696
2697 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2698 @IntrinsicCandidate
2699 public final float getFloatAcquire(Object o, long offset) {
2700 return getFloatVolatile(o, offset);
2701 }
2702
2703 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2704 @IntrinsicCandidate
2705 public final long getLongAcquire(Object o, long offset) {
2706 return getLongVolatile(o, offset);
2707 }
2708
2709 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2710 @IntrinsicCandidate
2711 public final double getDoubleAcquire(Object o, long offset) {
2712 return getDoubleVolatile(o, offset);
2713 }
2714
2715 /*
2716 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2717 * that do not guarantee immediate visibility of the store to
2718 * other threads. This method is generally only useful if the
2719 * underlying field is a Java volatile (or if an array cell, one
2720 * that is otherwise only accessed using volatile accesses).
2721 *
2722 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2723 */
2724
2725 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2726 @IntrinsicCandidate
2727 public final void putReferenceRelease(Object o, long offset, Object x) {
2728 putReferenceVolatile(o, offset, x);
2729 }
2730
2731 @ForceInline
2732 public final <V> void putFlatValueRelease(Object o, long offset, int layout, Class<?> valueType, V x) {
2733 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2734 storeFence();
2735 putFlatValue(o, offset, layout, valueType, x);
2736 }
2737
2738 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2739 @IntrinsicCandidate
2740 public final void putBooleanRelease(Object o, long offset, boolean x) {
2741 putBooleanVolatile(o, offset, x);
2742 }
2743
2744 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2745 @IntrinsicCandidate
2746 public final void putByteRelease(Object o, long offset, byte x) {
2747 putByteVolatile(o, offset, x);
2748 }
2749
2750 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2751 @IntrinsicCandidate
2752 public final void putShortRelease(Object o, long offset, short x) {
2753 putShortVolatile(o, offset, x);
2754 }
2755
2756 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2757 @IntrinsicCandidate
2758 public final void putCharRelease(Object o, long offset, char x) {
2759 putCharVolatile(o, offset, x);
2760 }
2761
2762 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2763 @IntrinsicCandidate
2764 public final void putIntRelease(Object o, long offset, int x) {
2765 putIntVolatile(o, offset, x);
2766 }
2767
2768 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2769 @IntrinsicCandidate
2770 public final void putFloatRelease(Object o, long offset, float x) {
2771 putFloatVolatile(o, offset, x);
2772 }
2773
2774 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2775 @IntrinsicCandidate
2776 public final void putLongRelease(Object o, long offset, long x) {
2777 putLongVolatile(o, offset, x);
2778 }
2779
2780 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2781 @IntrinsicCandidate
2782 public final void putDoubleRelease(Object o, long offset, double x) {
2783 putDoubleVolatile(o, offset, x);
2784 }
2785
2786 // ------------------------------ Opaque --------------------------------------
2787
2788 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2789 @IntrinsicCandidate
2790 public final Object getReferenceOpaque(Object o, long offset) {
2791 return getReferenceVolatile(o, offset);
2792 }
2793
2794 @ForceInline
2795 public final <V> Object getFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType) {
2796 // this is stronger than opaque semantics
2797 return getFlatValueAcquire(o, offset, layout, valueType);
2798 }
2799
2800 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2801 @IntrinsicCandidate
2802 public final boolean getBooleanOpaque(Object o, long offset) {
2803 return getBooleanVolatile(o, offset);
2804 }
2805
2806 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2807 @IntrinsicCandidate
2808 public final byte getByteOpaque(Object o, long offset) {
2809 return getByteVolatile(o, offset);
2810 }
2811
2812 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2813 @IntrinsicCandidate
2814 public final short getShortOpaque(Object o, long offset) {
2815 return getShortVolatile(o, offset);
2816 }
2817
2818 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2819 @IntrinsicCandidate
2820 public final char getCharOpaque(Object o, long offset) {
2821 return getCharVolatile(o, offset);
2822 }
2823
2824 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2825 @IntrinsicCandidate
2826 public final int getIntOpaque(Object o, long offset) {
2827 return getIntVolatile(o, offset);
2828 }
2829
2830 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2831 @IntrinsicCandidate
2832 public final float getFloatOpaque(Object o, long offset) {
2833 return getFloatVolatile(o, offset);
2834 }
2835
2836 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2837 @IntrinsicCandidate
2838 public final long getLongOpaque(Object o, long offset) {
2839 return getLongVolatile(o, offset);
2840 }
2841
2842 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2843 @IntrinsicCandidate
2844 public final double getDoubleOpaque(Object o, long offset) {
2845 return getDoubleVolatile(o, offset);
2846 }
2847
2848 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2849 @IntrinsicCandidate
2850 public final void putReferenceOpaque(Object o, long offset, Object x) {
2851 putReferenceVolatile(o, offset, x);
2852 }
2853
2854 @ForceInline
2855 public final <V> void putFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType, V x) {
2856 // this is stronger than opaque semantics
2857 putFlatValueRelease(o, offset, layout, valueType, x);
2858 }
2859
2860 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2861 @IntrinsicCandidate
2862 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2863 putBooleanVolatile(o, offset, x);
2864 }
2865
2866 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2867 @IntrinsicCandidate
2868 public final void putByteOpaque(Object o, long offset, byte x) {
2869 putByteVolatile(o, offset, x);
2870 }
2871
2872 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2873 @IntrinsicCandidate
2874 public final void putShortOpaque(Object o, long offset, short x) {
2875 putShortVolatile(o, offset, x);
2876 }
2877
2878 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2879 @IntrinsicCandidate
2880 public final void putCharOpaque(Object o, long offset, char x) {
2881 putCharVolatile(o, offset, x);
2882 }
2883
2884 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2885 @IntrinsicCandidate
2886 public final void putIntOpaque(Object o, long offset, int x) {
2887 putIntVolatile(o, offset, x);
2888 }
2889
2890 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2891 @IntrinsicCandidate
2892 public final void putFloatOpaque(Object o, long offset, float x) {
2893 putFloatVolatile(o, offset, x);
2894 }
2895
2896 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2897 @IntrinsicCandidate
2898 public final void putLongOpaque(Object o, long offset, long x) {
2899 putLongVolatile(o, offset, x);
2900 }
2901
2902 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2903 @IntrinsicCandidate
2904 public final void putDoubleOpaque(Object o, long offset, double x) {
2905 putDoubleVolatile(o, offset, x);
2906 }
2907
2908 @ForceInline
2909 private boolean compareAndSetFlatValueAsBytes(Object o, long offset, int layout, Class<?> valueType, Object expected, Object x) {
2910 // We turn the payload of an atomic value into a numeric value (of suitable type)
2911 // by storing the value into an array element (of matching layout) and by reading
2912 // back the array element as an integral value. After which we can implement the CAS
2913 // as a plain numeric CAS. Note: this only works if the payload contains no oops
2914 // (see VarHandles::isAtomicFlat).
2915 Object[] expectedArray = newSpecialArray(valueType, 1, layout);
2916 Object xArray = newSpecialArray(valueType, 1, layout);
2917 long base = arrayInstanceBaseOffset(expectedArray);
2918 int scale = arrayInstanceIndexScale(expectedArray);
2919 putFlatValue(expectedArray, base, layout, valueType, expected);
2920 putFlatValue(xArray, base, layout, valueType, x);
2921 switch (scale) {
2922 case 1: {
2923 byte expectedByte = getByte(expectedArray, base);
2924 byte xByte = getByte(xArray, base);
2925 return compareAndSetByte(o, offset, expectedByte, xByte);
2926 }
2927 case 2: {
2928 short expectedShort = getShort(expectedArray, base);
2929 short xShort = getShort(xArray, base);
2930 return compareAndSetShort(o, offset, expectedShort, xShort);
2931 }
2932 case 4: {
2933 int expectedInt = getInt(expectedArray, base);
2934 int xInt = getInt(xArray, base);
2935 return compareAndSetInt(o, offset, expectedInt, xInt);
2936 }
2937 case 8: {
2938 long expectedLong = getLong(expectedArray, base);
2939 long xLong = getLong(xArray, base);
2940 return compareAndSetLong(o, offset, expectedLong, xLong);
2941 }
2942 default: {
2943 throw new UnsupportedOperationException();
2944 }
2945 }
2946 }
2947
2948 /**
2949 * Unblocks the given thread blocked on {@code park}, or, if it is
2950 * not blocked, causes the subsequent call to {@code park} not to
2951 * block. Note: this operation is "unsafe" solely because the
2952 * caller must somehow ensure that the thread has not been
2953 * destroyed. Nothing special is usually required to ensure this
2954 * when called from Java (in which there will ordinarily be a live
2955 * reference to the thread) but this is not nearly-automatically
2956 * so when calling from native code.
2957 *
2958 * @param thread the thread to unpark.
2959 */
2960 @IntrinsicCandidate
2961 public native void unpark(Object thread);
2962
2963 /**
2964 * Blocks current thread, returning when a balancing
2965 * {@code unpark} occurs, or a balancing {@code unpark} has
2966 * already occurred, or the thread is interrupted, or, if not
2967 * absolute and time is not zero, the given time nanoseconds have
2968 * elapsed, or if absolute, the given deadline in milliseconds
2969 * since Epoch has passed, or spuriously (i.e., returning for no
2970 * "reason"). Note: This operation is in the Unsafe class only
2971 * because {@code unpark} is, so it would be strange to place it
2972 * elsewhere.
2973 */
2974 @IntrinsicCandidate
2975 public native void park(boolean isAbsolute, long time);
2976
2977 /**
2978 * Gets the load average in the system run queue assigned
2979 * to the available processors averaged over various periods of time.
2980 * This method retrieves the given {@code nelem} samples and
2981 * assigns to the elements of the given {@code loadavg} array.
2982 * The system imposes a maximum of 3 samples, representing
2983 * averages over the last 1, 5, and 15 minutes, respectively.
2984 *
2985 * @param loadavg an array of double of size nelems
2986 * @param nelems the number of samples to be retrieved and
2987 * must be 1 to 3.
2988 *
2989 * @return the number of samples actually retrieved; or -1
2990 * if the load average is unobtainable.
2991 */
2992 public int getLoadAverage(double[] loadavg, int nelems) {
2993 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2994 throw new ArrayIndexOutOfBoundsException();
2995 }
2996
2997 return getLoadAverage0(loadavg, nelems);
2998 }
2999
3000 // The following contain CAS-based Java implementations used on
3001 // platforms not supporting native instructions
3002
3003 /**
3004 * Atomically adds the given value to the current value of a field
3005 * or array element within the given object {@code o}
3006 * at the given {@code offset}.
3007 *
3008 * @param o object/array to update the field/element in
3009 * @param offset field/element offset
3010 * @param delta the value to add
3011 * @return the previous value
3012 * @since 1.8
3013 */
3014 @IntrinsicCandidate
3015 public final int getAndAddInt(Object o, long offset, int delta) {
3016 int v;
3017 do {
3018 v = getIntVolatile(o, offset);
3019 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
3020 return v;
3021 }
3022
3023 @ForceInline
3024 public final int getAndAddIntRelease(Object o, long offset, int delta) {
3025 int v;
3026 do {
3027 v = getInt(o, offset);
3028 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
3029 return v;
3030 }
3031
3032 @ForceInline
3033 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
3034 int v;
3035 do {
3036 v = getIntAcquire(o, offset);
3037 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
3038 return v;
3039 }
3040
3041 /**
3042 * Atomically adds the given value to the current value of a field
3043 * or array element within the given object {@code o}
3044 * at the given {@code offset}.
3045 *
3046 * @param o object/array to update the field/element in
3047 * @param offset field/element offset
3048 * @param delta the value to add
3049 * @return the previous value
3050 * @since 1.8
3051 */
3052 @IntrinsicCandidate
3053 public final long getAndAddLong(Object o, long offset, long delta) {
3054 long v;
3055 do {
3056 v = getLongVolatile(o, offset);
3057 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
3058 return v;
3059 }
3060
3061 @ForceInline
3062 public final long getAndAddLongRelease(Object o, long offset, long delta) {
3063 long v;
3064 do {
3065 v = getLong(o, offset);
3066 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
3067 return v;
3068 }
3069
3070 @ForceInline
3071 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
3072 long v;
3073 do {
3074 v = getLongAcquire(o, offset);
3075 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
3076 return v;
3077 }
3078
3079 @IntrinsicCandidate
3080 public final byte getAndAddByte(Object o, long offset, byte delta) {
3081 byte v;
3082 do {
3083 v = getByteVolatile(o, offset);
3084 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
3085 return v;
3086 }
3087
3088 @ForceInline
3089 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
3090 byte v;
3091 do {
3092 v = getByte(o, offset);
3093 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
3094 return v;
3095 }
3096
3097 @ForceInline
3098 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
3099 byte v;
3100 do {
3101 v = getByteAcquire(o, offset);
3102 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
3103 return v;
3104 }
3105
3106 @IntrinsicCandidate
3107 public final short getAndAddShort(Object o, long offset, short delta) {
3108 short v;
3109 do {
3110 v = getShortVolatile(o, offset);
3111 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
3112 return v;
3113 }
3114
3115 @ForceInline
3116 public final short getAndAddShortRelease(Object o, long offset, short delta) {
3117 short v;
3118 do {
3119 v = getShort(o, offset);
3120 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
3121 return v;
3122 }
3123
3124 @ForceInline
3125 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
3126 short v;
3127 do {
3128 v = getShortAcquire(o, offset);
3129 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
3130 return v;
3131 }
3132
3133 @ForceInline
3134 public final char getAndAddChar(Object o, long offset, char delta) {
3135 return (char) getAndAddShort(o, offset, (short) delta);
3136 }
3137
3138 @ForceInline
3139 public final char getAndAddCharRelease(Object o, long offset, char delta) {
3140 return (char) getAndAddShortRelease(o, offset, (short) delta);
3141 }
3142
3143 @ForceInline
3144 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
3145 return (char) getAndAddShortAcquire(o, offset, (short) delta);
3146 }
3147
3148 @ForceInline
3149 public final float getAndAddFloat(Object o, long offset, float delta) {
3150 int expectedBits;
3151 float v;
3152 do {
3153 // Load and CAS with the raw bits to avoid issues with NaNs and
3154 // possible bit conversion from signaling NaNs to quiet NaNs that
3155 // may result in the loop not terminating.
3156 expectedBits = getIntVolatile(o, offset);
3157 v = Float.intBitsToFloat(expectedBits);
3158 } while (!weakCompareAndSetInt(o, offset,
3159 expectedBits, Float.floatToRawIntBits(v + delta)));
3160 return v;
3161 }
3162
3163 @ForceInline
3164 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
3165 int expectedBits;
3166 float v;
3167 do {
3168 // Load and CAS with the raw bits to avoid issues with NaNs and
3169 // possible bit conversion from signaling NaNs to quiet NaNs that
3170 // may result in the loop not terminating.
3171 expectedBits = getInt(o, offset);
3172 v = Float.intBitsToFloat(expectedBits);
3173 } while (!weakCompareAndSetIntRelease(o, offset,
3174 expectedBits, Float.floatToRawIntBits(v + delta)));
3175 return v;
3176 }
3177
3178 @ForceInline
3179 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
3180 int expectedBits;
3181 float v;
3182 do {
3183 // Load and CAS with the raw bits to avoid issues with NaNs and
3184 // possible bit conversion from signaling NaNs to quiet NaNs that
3185 // may result in the loop not terminating.
3186 expectedBits = getIntAcquire(o, offset);
3187 v = Float.intBitsToFloat(expectedBits);
3188 } while (!weakCompareAndSetIntAcquire(o, offset,
3189 expectedBits, Float.floatToRawIntBits(v + delta)));
3190 return v;
3191 }
3192
3193 @ForceInline
3194 public final double getAndAddDouble(Object o, long offset, double delta) {
3195 long expectedBits;
3196 double v;
3197 do {
3198 // Load and CAS with the raw bits to avoid issues with NaNs and
3199 // possible bit conversion from signaling NaNs to quiet NaNs that
3200 // may result in the loop not terminating.
3201 expectedBits = getLongVolatile(o, offset);
3202 v = Double.longBitsToDouble(expectedBits);
3203 } while (!weakCompareAndSetLong(o, offset,
3204 expectedBits, Double.doubleToRawLongBits(v + delta)));
3205 return v;
3206 }
3207
3208 @ForceInline
3209 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
3210 long expectedBits;
3211 double v;
3212 do {
3213 // Load and CAS with the raw bits to avoid issues with NaNs and
3214 // possible bit conversion from signaling NaNs to quiet NaNs that
3215 // may result in the loop not terminating.
3216 expectedBits = getLong(o, offset);
3217 v = Double.longBitsToDouble(expectedBits);
3218 } while (!weakCompareAndSetLongRelease(o, offset,
3219 expectedBits, Double.doubleToRawLongBits(v + delta)));
3220 return v;
3221 }
3222
3223 @ForceInline
3224 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
3225 long expectedBits;
3226 double v;
3227 do {
3228 // Load and CAS with the raw bits to avoid issues with NaNs and
3229 // possible bit conversion from signaling NaNs to quiet NaNs that
3230 // may result in the loop not terminating.
3231 expectedBits = getLongAcquire(o, offset);
3232 v = Double.longBitsToDouble(expectedBits);
3233 } while (!weakCompareAndSetLongAcquire(o, offset,
3234 expectedBits, Double.doubleToRawLongBits(v + delta)));
3235 return v;
3236 }
3237
3238 /**
3239 * Atomically exchanges the given value with the current value of
3240 * a field or array element within the given object {@code o}
3241 * at the given {@code offset}.
3242 *
3243 * @param o object/array to update the field/element in
3244 * @param offset field/element offset
3245 * @param newValue new value
3246 * @return the previous value
3247 * @since 1.8
3248 */
3249 @IntrinsicCandidate
3250 public final int getAndSetInt(Object o, long offset, int newValue) {
3251 int v;
3252 do {
3253 v = getIntVolatile(o, offset);
3254 } while (!weakCompareAndSetInt(o, offset, v, newValue));
3255 return v;
3256 }
3257
3258 @ForceInline
3259 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
3260 int v;
3261 do {
3262 v = getInt(o, offset);
3263 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
3264 return v;
3265 }
3266
3267 @ForceInline
3268 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
3269 int v;
3270 do {
3271 v = getIntAcquire(o, offset);
3272 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
3273 return v;
3274 }
3275
3276 /**
3277 * Atomically exchanges the given value with the current value of
3278 * a field or array element within the given object {@code o}
3279 * at the given {@code offset}.
3280 *
3281 * @param o object/array to update the field/element in
3282 * @param offset field/element offset
3283 * @param newValue new value
3284 * @return the previous value
3285 * @since 1.8
3286 */
3287 @IntrinsicCandidate
3288 public final long getAndSetLong(Object o, long offset, long newValue) {
3289 long v;
3290 do {
3291 v = getLongVolatile(o, offset);
3292 } while (!weakCompareAndSetLong(o, offset, v, newValue));
3293 return v;
3294 }
3295
3296 @ForceInline
3297 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
3298 long v;
3299 do {
3300 v = getLong(o, offset);
3301 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
3302 return v;
3303 }
3304
3305 @ForceInline
3306 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
3307 long v;
3308 do {
3309 v = getLongAcquire(o, offset);
3310 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
3311 return v;
3312 }
3313
3314 /**
3315 * Atomically exchanges the given reference value with the current
3316 * reference value of a field or array element within the given
3317 * object {@code o} at the given {@code offset}.
3318 *
3319 * @param o object/array to update the field/element in
3320 * @param offset field/element offset
3321 * @param newValue new value
3322 * @return the previous value
3323 * @since 1.8
3324 */
3325 @IntrinsicCandidate
3326 public final Object getAndSetReference(Object o, long offset, Object newValue) {
3327 Object v;
3328 do {
3329 v = getReferenceVolatile(o, offset);
3330 } while (!weakCompareAndSetReference(o, offset, v, newValue));
3331 return v;
3332 }
3333
3334 @ForceInline
3335 public final Object getAndSetReference(Object o, long offset, Class<?> valueType, Object newValue) {
3336 Object v;
3337 do {
3338 v = getReferenceVolatile(o, offset);
3339 } while (!compareAndSetReference(o, offset, valueType, v, newValue));
3340 return v;
3341 }
3342
3343 @ForceInline
3344 public Object getAndSetFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, Object newValue) {
3345 Object v;
3346 do {
3347 v = getFlatValueVolatile(o, offset, layoutKind, valueType);
3348 } while (!compareAndSetFlatValue(o, offset, layoutKind, valueType, v, newValue));
3349 return v;
3350 }
3351
3352 @ForceInline
3353 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
3354 Object v;
3355 do {
3356 v = getReference(o, offset);
3357 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
3358 return v;
3359 }
3360
3361 @ForceInline
3362 public final Object getAndSetReferenceRelease(Object o, long offset, Class<?> valueType, Object newValue) {
3363 return getAndSetReference(o, offset, valueType, newValue);
3364 }
3365
3366 @ForceInline
3367 public Object getAndSetFlatValueRelease(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3368 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3369 }
3370
3371 @ForceInline
3372 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
3373 Object v;
3374 do {
3375 v = getReferenceAcquire(o, offset);
3376 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
3377 return v;
3378 }
3379
3380 @ForceInline
3381 public final Object getAndSetReferenceAcquire(Object o, long offset, Class<?> valueType, Object newValue) {
3382 return getAndSetReference(o, offset, valueType, newValue);
3383 }
3384
3385 @ForceInline
3386 public Object getAndSetFlatValueAcquire(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3387 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3388 }
3389
3390 @IntrinsicCandidate
3391 public final byte getAndSetByte(Object o, long offset, byte newValue) {
3392 byte v;
3393 do {
3394 v = getByteVolatile(o, offset);
3395 } while (!weakCompareAndSetByte(o, offset, v, newValue));
3396 return v;
3397 }
3398
3399 @ForceInline
3400 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
3401 byte v;
3402 do {
3403 v = getByte(o, offset);
3404 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
3405 return v;
3406 }
3407
3408 @ForceInline
3409 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
3410 byte v;
3411 do {
3412 v = getByteAcquire(o, offset);
3413 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
3414 return v;
3415 }
3416
3417 @ForceInline
3418 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
3419 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
3420 }
3421
3422 @ForceInline
3423 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
3424 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
3425 }
3426
3427 @ForceInline
3428 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
3429 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
3430 }
3431
3432 @IntrinsicCandidate
3433 public final short getAndSetShort(Object o, long offset, short newValue) {
3434 short v;
3435 do {
3436 v = getShortVolatile(o, offset);
3437 } while (!weakCompareAndSetShort(o, offset, v, newValue));
3438 return v;
3439 }
3440
3441 @ForceInline
3442 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
3443 short v;
3444 do {
3445 v = getShort(o, offset);
3446 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
3447 return v;
3448 }
3449
3450 @ForceInline
3451 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
3452 short v;
3453 do {
3454 v = getShortAcquire(o, offset);
3455 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
3456 return v;
3457 }
3458
3459 @ForceInline
3460 public final char getAndSetChar(Object o, long offset, char newValue) {
3461 return s2c(getAndSetShort(o, offset, c2s(newValue)));
3462 }
3463
3464 @ForceInline
3465 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
3466 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
3467 }
3468
3469 @ForceInline
3470 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
3471 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
3472 }
3473
3474 @ForceInline
3475 public final float getAndSetFloat(Object o, long offset, float newValue) {
3476 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
3477 return Float.intBitsToFloat(v);
3478 }
3479
3480 @ForceInline
3481 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
3482 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
3483 return Float.intBitsToFloat(v);
3484 }
3485
3486 @ForceInline
3487 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
3488 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
3489 return Float.intBitsToFloat(v);
3490 }
3491
3492 @ForceInline
3493 public final double getAndSetDouble(Object o, long offset, double newValue) {
3494 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
3495 return Double.longBitsToDouble(v);
3496 }
3497
3498 @ForceInline
3499 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
3500 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
3501 return Double.longBitsToDouble(v);
3502 }
3503
3504 @ForceInline
3505 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
3506 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
3507 return Double.longBitsToDouble(v);
3508 }
3509
3510
3511 // The following contain CAS-based Java implementations used on
3512 // platforms not supporting native instructions
3513
3514 @ForceInline
3515 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
3516 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
3517 }
3518
3519 @ForceInline
3520 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
3521 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
3522 }
3523
3524 @ForceInline
3525 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
3526 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
3527 }
3528
3529 @ForceInline
3530 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
3531 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
3532 }
3533
3534 @ForceInline
3535 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
3536 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
3537 }
3538
3539 @ForceInline
3540 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
3541 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
3542 }
3543
3544 @ForceInline
3545 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
3546 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
3547 }
3548
3549 @ForceInline
3550 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
3551 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
3552 }
3553
3554 @ForceInline
3555 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
3556 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
3557 }
3558
3559
3560 @ForceInline
3561 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
3562 byte current;
3563 do {
3564 current = getByteVolatile(o, offset);
3565 } while (!weakCompareAndSetByte(o, offset,
3566 current, (byte) (current | mask)));
3567 return current;
3568 }
3569
3570 @ForceInline
3571 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
3572 byte current;
3573 do {
3574 current = getByte(o, offset);
3575 } while (!weakCompareAndSetByteRelease(o, offset,
3576 current, (byte) (current | mask)));
3577 return current;
3578 }
3579
3580 @ForceInline
3581 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
3582 byte current;
3583 do {
3584 // Plain read, the value is a hint, the acquire CAS does the work
3585 current = getByte(o, offset);
3586 } while (!weakCompareAndSetByteAcquire(o, offset,
3587 current, (byte) (current | mask)));
3588 return current;
3589 }
3590
3591 @ForceInline
3592 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
3593 byte current;
3594 do {
3595 current = getByteVolatile(o, offset);
3596 } while (!weakCompareAndSetByte(o, offset,
3597 current, (byte) (current & mask)));
3598 return current;
3599 }
3600
3601 @ForceInline
3602 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
3603 byte current;
3604 do {
3605 current = getByte(o, offset);
3606 } while (!weakCompareAndSetByteRelease(o, offset,
3607 current, (byte) (current & mask)));
3608 return current;
3609 }
3610
3611 @ForceInline
3612 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
3613 byte current;
3614 do {
3615 // Plain read, the value is a hint, the acquire CAS does the work
3616 current = getByte(o, offset);
3617 } while (!weakCompareAndSetByteAcquire(o, offset,
3618 current, (byte) (current & mask)));
3619 return current;
3620 }
3621
3622 @ForceInline
3623 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
3624 byte current;
3625 do {
3626 current = getByteVolatile(o, offset);
3627 } while (!weakCompareAndSetByte(o, offset,
3628 current, (byte) (current ^ mask)));
3629 return current;
3630 }
3631
3632 @ForceInline
3633 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
3634 byte current;
3635 do {
3636 current = getByte(o, offset);
3637 } while (!weakCompareAndSetByteRelease(o, offset,
3638 current, (byte) (current ^ mask)));
3639 return current;
3640 }
3641
3642 @ForceInline
3643 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3644 byte current;
3645 do {
3646 // Plain read, the value is a hint, the acquire CAS does the work
3647 current = getByte(o, offset);
3648 } while (!weakCompareAndSetByteAcquire(o, offset,
3649 current, (byte) (current ^ mask)));
3650 return current;
3651 }
3652
3653
3654 @ForceInline
3655 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3656 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3657 }
3658
3659 @ForceInline
3660 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3661 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3662 }
3663
3664 @ForceInline
3665 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3666 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3667 }
3668
3669 @ForceInline
3670 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3671 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3672 }
3673
3674 @ForceInline
3675 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3676 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3677 }
3678
3679 @ForceInline
3680 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3681 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3682 }
3683
3684 @ForceInline
3685 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3686 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3687 }
3688
3689 @ForceInline
3690 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3691 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3692 }
3693
3694 @ForceInline
3695 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3696 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3697 }
3698
3699
3700 @ForceInline
3701 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3702 short current;
3703 do {
3704 current = getShortVolatile(o, offset);
3705 } while (!weakCompareAndSetShort(o, offset,
3706 current, (short) (current | mask)));
3707 return current;
3708 }
3709
3710 @ForceInline
3711 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3712 short current;
3713 do {
3714 current = getShort(o, offset);
3715 } while (!weakCompareAndSetShortRelease(o, offset,
3716 current, (short) (current | mask)));
3717 return current;
3718 }
3719
3720 @ForceInline
3721 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3722 short current;
3723 do {
3724 // Plain read, the value is a hint, the acquire CAS does the work
3725 current = getShort(o, offset);
3726 } while (!weakCompareAndSetShortAcquire(o, offset,
3727 current, (short) (current | mask)));
3728 return current;
3729 }
3730
3731 @ForceInline
3732 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3733 short current;
3734 do {
3735 current = getShortVolatile(o, offset);
3736 } while (!weakCompareAndSetShort(o, offset,
3737 current, (short) (current & mask)));
3738 return current;
3739 }
3740
3741 @ForceInline
3742 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3743 short current;
3744 do {
3745 current = getShort(o, offset);
3746 } while (!weakCompareAndSetShortRelease(o, offset,
3747 current, (short) (current & mask)));
3748 return current;
3749 }
3750
3751 @ForceInline
3752 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3753 short current;
3754 do {
3755 // Plain read, the value is a hint, the acquire CAS does the work
3756 current = getShort(o, offset);
3757 } while (!weakCompareAndSetShortAcquire(o, offset,
3758 current, (short) (current & mask)));
3759 return current;
3760 }
3761
3762 @ForceInline
3763 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3764 short current;
3765 do {
3766 current = getShortVolatile(o, offset);
3767 } while (!weakCompareAndSetShort(o, offset,
3768 current, (short) (current ^ mask)));
3769 return current;
3770 }
3771
3772 @ForceInline
3773 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3774 short current;
3775 do {
3776 current = getShort(o, offset);
3777 } while (!weakCompareAndSetShortRelease(o, offset,
3778 current, (short) (current ^ mask)));
3779 return current;
3780 }
3781
3782 @ForceInline
3783 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3784 short current;
3785 do {
3786 // Plain read, the value is a hint, the acquire CAS does the work
3787 current = getShort(o, offset);
3788 } while (!weakCompareAndSetShortAcquire(o, offset,
3789 current, (short) (current ^ mask)));
3790 return current;
3791 }
3792
3793
3794 @ForceInline
3795 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3796 int current;
3797 do {
3798 current = getIntVolatile(o, offset);
3799 } while (!weakCompareAndSetInt(o, offset,
3800 current, current | mask));
3801 return current;
3802 }
3803
3804 @ForceInline
3805 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3806 int current;
3807 do {
3808 current = getInt(o, offset);
3809 } while (!weakCompareAndSetIntRelease(o, offset,
3810 current, current | mask));
3811 return current;
3812 }
3813
3814 @ForceInline
3815 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3816 int current;
3817 do {
3818 // Plain read, the value is a hint, the acquire CAS does the work
3819 current = getInt(o, offset);
3820 } while (!weakCompareAndSetIntAcquire(o, offset,
3821 current, current | mask));
3822 return current;
3823 }
3824
3825 /**
3826 * Atomically replaces the current value of a field or array element within
3827 * the given object with the result of bitwise AND between the current value
3828 * and mask.
3829 *
3830 * @param o object/array to update the field/element in
3831 * @param offset field/element offset
3832 * @param mask the mask value
3833 * @return the previous value
3834 * @since 9
3835 */
3836 @ForceInline
3837 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3838 int current;
3839 do {
3840 current = getIntVolatile(o, offset);
3841 } while (!weakCompareAndSetInt(o, offset,
3842 current, current & mask));
3843 return current;
3844 }
3845
3846 @ForceInline
3847 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3848 int current;
3849 do {
3850 current = getInt(o, offset);
3851 } while (!weakCompareAndSetIntRelease(o, offset,
3852 current, current & mask));
3853 return current;
3854 }
3855
3856 @ForceInline
3857 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3858 int current;
3859 do {
3860 // Plain read, the value is a hint, the acquire CAS does the work
3861 current = getInt(o, offset);
3862 } while (!weakCompareAndSetIntAcquire(o, offset,
3863 current, current & mask));
3864 return current;
3865 }
3866
3867 @ForceInline
3868 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3869 int current;
3870 do {
3871 current = getIntVolatile(o, offset);
3872 } while (!weakCompareAndSetInt(o, offset,
3873 current, current ^ mask));
3874 return current;
3875 }
3876
3877 @ForceInline
3878 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3879 int current;
3880 do {
3881 current = getInt(o, offset);
3882 } while (!weakCompareAndSetIntRelease(o, offset,
3883 current, current ^ mask));
3884 return current;
3885 }
3886
3887 @ForceInline
3888 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3889 int current;
3890 do {
3891 // Plain read, the value is a hint, the acquire CAS does the work
3892 current = getInt(o, offset);
3893 } while (!weakCompareAndSetIntAcquire(o, offset,
3894 current, current ^ mask));
3895 return current;
3896 }
3897
3898
3899 @ForceInline
3900 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3901 long current;
3902 do {
3903 current = getLongVolatile(o, offset);
3904 } while (!weakCompareAndSetLong(o, offset,
3905 current, current | mask));
3906 return current;
3907 }
3908
3909 @ForceInline
3910 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3911 long current;
3912 do {
3913 current = getLong(o, offset);
3914 } while (!weakCompareAndSetLongRelease(o, offset,
3915 current, current | mask));
3916 return current;
3917 }
3918
3919 @ForceInline
3920 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3921 long current;
3922 do {
3923 // Plain read, the value is a hint, the acquire CAS does the work
3924 current = getLong(o, offset);
3925 } while (!weakCompareAndSetLongAcquire(o, offset,
3926 current, current | mask));
3927 return current;
3928 }
3929
3930 @ForceInline
3931 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3932 long current;
3933 do {
3934 current = getLongVolatile(o, offset);
3935 } while (!weakCompareAndSetLong(o, offset,
3936 current, current & mask));
3937 return current;
3938 }
3939
3940 @ForceInline
3941 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3942 long current;
3943 do {
3944 current = getLong(o, offset);
3945 } while (!weakCompareAndSetLongRelease(o, offset,
3946 current, current & mask));
3947 return current;
3948 }
3949
3950 @ForceInline
3951 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3952 long current;
3953 do {
3954 // Plain read, the value is a hint, the acquire CAS does the work
3955 current = getLong(o, offset);
3956 } while (!weakCompareAndSetLongAcquire(o, offset,
3957 current, current & mask));
3958 return current;
3959 }
3960
3961 @ForceInline
3962 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3963 long current;
3964 do {
3965 current = getLongVolatile(o, offset);
3966 } while (!weakCompareAndSetLong(o, offset,
3967 current, current ^ mask));
3968 return current;
3969 }
3970
3971 @ForceInline
3972 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3973 long current;
3974 do {
3975 current = getLong(o, offset);
3976 } while (!weakCompareAndSetLongRelease(o, offset,
3977 current, current ^ mask));
3978 return current;
3979 }
3980
3981 @ForceInline
3982 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3983 long current;
3984 do {
3985 // Plain read, the value is a hint, the acquire CAS does the work
3986 current = getLong(o, offset);
3987 } while (!weakCompareAndSetLongAcquire(o, offset,
3988 current, current ^ mask));
3989 return current;
3990 }
3991
3992
3993
3994 /**
3995 * Ensures that loads before the fence will not be reordered with loads and
3996 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3997 *
3998 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3999 * (an "acquire fence").
4000 *
4001 * Provides a LoadLoad barrier followed by a LoadStore barrier.
4002 *
4003 * @since 1.8
4004 */
4005 @IntrinsicCandidate
4006 public final void loadFence() {
4007 // If loadFence intrinsic is not available, fall back to full fence.
4008 fullFence();
4009 }
4010
4011 /**
4012 * Ensures that loads and stores before the fence will not be reordered with
4013 * stores after the fence; a "StoreStore plus LoadStore barrier".
4014 *
4015 * Corresponds to C11 atomic_thread_fence(memory_order_release)
4016 * (a "release fence").
4017 *
4018 * Provides a StoreStore barrier followed by a LoadStore barrier.
4019 *
4020 * @since 1.8
4021 */
4022 @IntrinsicCandidate
4023 public final void storeFence() {
4024 // If storeFence intrinsic is not available, fall back to full fence.
4025 fullFence();
4026 }
4027
4028 /**
4029 * Ensures that loads and stores before the fence will not be reordered
4030 * with loads and stores after the fence. Implies the effects of both
4031 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
4032 * barrier.
4033 *
4034 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
4035 * @since 1.8
4036 */
4037 @IntrinsicCandidate
4038 public native void fullFence();
4039
4040 /**
4041 * Ensures that loads before the fence will not be reordered with
4042 * loads after the fence.
4043 *
4044 * @implNote
4045 * This method is operationally equivalent to {@link #loadFence()}.
4046 *
4047 * @since 9
4048 */
4049 public final void loadLoadFence() {
4050 loadFence();
4051 }
4052
4053 /**
4054 * Ensures that stores before the fence will not be reordered with
4055 * stores after the fence.
4056 *
4057 * @since 9
4058 */
4059 @IntrinsicCandidate
4060 public final void storeStoreFence() {
4061 // If storeStoreFence intrinsic is not available, fall back to storeFence.
4062 storeFence();
4063 }
4064
4065 /**
4066 * Throws IllegalAccessError; for use by the VM for access control
4067 * error support.
4068 * @since 1.8
4069 */
4070 private static void throwIllegalAccessError() {
4071 throw new IllegalAccessError();
4072 }
4073
4074 /**
4075 * Throws NoSuchMethodError; for use by the VM for redefinition support.
4076 * @since 13
4077 */
4078 private static void throwNoSuchMethodError() {
4079 throw new NoSuchMethodError();
4080 }
4081
4082 /**
4083 * @return Returns true if the native byte ordering of this
4084 * platform is big-endian, false if it is little-endian.
4085 */
4086 public final boolean isBigEndian() { return BIG_ENDIAN; }
4087
4088 /**
4089 * @return Returns true if this platform is capable of performing
4090 * accesses at addresses which are not aligned for the type of the
4091 * primitive type being accessed, false otherwise.
4092 */
4093 public final boolean unalignedAccess() { return UNALIGNED_ACCESS; }
4094
4095 /**
4096 * Fetches a value at some byte offset into a given Java object.
4097 * More specifically, fetches a value within the given object
4098 * <code>o</code> at the given offset, or (if <code>o</code> is
4099 * null) from the memory address whose numerical value is the
4100 * given offset. <p>
4101 *
4102 * The specification of this method is the same as {@link
4103 * #getLong(Object, long)} except that the offset does not need to
4104 * have been obtained from {@link #objectFieldOffset} on the
4105 * {@link java.lang.reflect.Field} of some Java field. The value
4106 * in memory is raw data, and need not correspond to any Java
4107 * variable. Unless <code>o</code> is null, the value accessed
4108 * must be entirely within the allocated object. The endianness
4109 * of the value in memory is the endianness of the native platform.
4110 *
4111 * <p> The read will be atomic with respect to the largest power
4112 * of two that divides the GCD of the offset and the storage size.
4113 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
4114 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
4115 * respectively. There are no other guarantees of atomicity.
4116 * <p>
4117 * 8-byte atomicity is only guaranteed on platforms on which
4118 * support atomic accesses to longs.
4119 *
4120 * @param o Java heap object in which the value resides, if any, else
4121 * null
4122 * @param offset The offset in bytes from the start of the object
4123 * @return the value fetched from the indicated object
4124 * @throws RuntimeException No defined exceptions are thrown, not even
4125 * {@link NullPointerException}
4126 * @since 9
4127 */
4128 @IntrinsicCandidate
4129 public final long getLongUnaligned(Object o, long offset) {
4130 if ((offset & 7) == 0) {
4131 return getLong(o, offset);
4132 } else if ((offset & 3) == 0) {
4133 return makeLong(getInt(o, offset),
4134 getInt(o, offset + 4));
4135 } else if ((offset & 1) == 0) {
4136 return makeLong(getShort(o, offset),
4137 getShort(o, offset + 2),
4138 getShort(o, offset + 4),
4139 getShort(o, offset + 6));
4140 } else {
4141 return makeLong(getByte(o, offset),
4142 getByte(o, offset + 1),
4143 getByte(o, offset + 2),
4144 getByte(o, offset + 3),
4145 getByte(o, offset + 4),
4146 getByte(o, offset + 5),
4147 getByte(o, offset + 6),
4148 getByte(o, offset + 7));
4149 }
4150 }
4151 /**
4152 * As {@link #getLongUnaligned(Object, long)} but with an
4153 * additional argument which specifies the endianness of the value
4154 * as stored in memory.
4155 *
4156 * @param o Java heap object in which the variable resides
4157 * @param offset The offset in bytes from the start of the object
4158 * @param bigEndian The endianness of the value
4159 * @return the value fetched from the indicated object
4160 * @since 9
4161 */
4162 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
4163 return convEndian(bigEndian, getLongUnaligned(o, offset));
4164 }
4165
4166 /** @see #getLongUnaligned(Object, long) */
4167 @IntrinsicCandidate
4168 public final int getIntUnaligned(Object o, long offset) {
4169 if ((offset & 3) == 0) {
4170 return getInt(o, offset);
4171 } else if ((offset & 1) == 0) {
4172 return makeInt(getShort(o, offset),
4173 getShort(o, offset + 2));
4174 } else {
4175 return makeInt(getByte(o, offset),
4176 getByte(o, offset + 1),
4177 getByte(o, offset + 2),
4178 getByte(o, offset + 3));
4179 }
4180 }
4181 /** @see #getLongUnaligned(Object, long, boolean) */
4182 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
4183 return convEndian(bigEndian, getIntUnaligned(o, offset));
4184 }
4185
4186 /** @see #getLongUnaligned(Object, long) */
4187 @IntrinsicCandidate
4188 public final short getShortUnaligned(Object o, long offset) {
4189 if ((offset & 1) == 0) {
4190 return getShort(o, offset);
4191 } else {
4192 return makeShort(getByte(o, offset),
4193 getByte(o, offset + 1));
4194 }
4195 }
4196 /** @see #getLongUnaligned(Object, long, boolean) */
4197 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
4198 return convEndian(bigEndian, getShortUnaligned(o, offset));
4199 }
4200
4201 /** @see #getLongUnaligned(Object, long) */
4202 @IntrinsicCandidate
4203 public final char getCharUnaligned(Object o, long offset) {
4204 if ((offset & 1) == 0) {
4205 return getChar(o, offset);
4206 } else {
4207 return (char)makeShort(getByte(o, offset),
4208 getByte(o, offset + 1));
4209 }
4210 }
4211
4212 /** @see #getLongUnaligned(Object, long, boolean) */
4213 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
4214 return convEndian(bigEndian, getCharUnaligned(o, offset));
4215 }
4216
4217 /**
4218 * Stores a value at some byte offset into a given Java object.
4219 * <p>
4220 * The specification of this method is the same as {@link
4221 * #getLong(Object, long)} except that the offset does not need to
4222 * have been obtained from {@link #objectFieldOffset} on the
4223 * {@link java.lang.reflect.Field} of some Java field. The value
4224 * in memory is raw data, and need not correspond to any Java
4225 * variable. The endianness of the value in memory is the
4226 * endianness of the native platform.
4227 * <p>
4228 * The write will be atomic with respect to the largest power of
4229 * two that divides the GCD of the offset and the storage size.
4230 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
4231 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
4232 * respectively. There are no other guarantees of atomicity.
4233 * <p>
4234 * 8-byte atomicity is only guaranteed on platforms on which
4235 * support atomic accesses to longs.
4236 *
4237 * @param o Java heap object in which the value resides, if any, else
4238 * null
4239 * @param offset The offset in bytes from the start of the object
4240 * @param x the value to store
4241 * @throws RuntimeException No defined exceptions are thrown, not even
4242 * {@link NullPointerException}
4243 * @since 9
4244 */
4245 @IntrinsicCandidate
4246 public final void putLongUnaligned(Object o, long offset, long x) {
4247 if ((offset & 7) == 0) {
4248 putLong(o, offset, x);
4249 } else if ((offset & 3) == 0) {
4250 putLongParts(o, offset,
4251 (int)(x >> 0),
4252 (int)(x >>> 32));
4253 } else if ((offset & 1) == 0) {
4254 putLongParts(o, offset,
4255 (short)(x >>> 0),
4256 (short)(x >>> 16),
4257 (short)(x >>> 32),
4258 (short)(x >>> 48));
4259 } else {
4260 putLongParts(o, offset,
4261 (byte)(x >>> 0),
4262 (byte)(x >>> 8),
4263 (byte)(x >>> 16),
4264 (byte)(x >>> 24),
4265 (byte)(x >>> 32),
4266 (byte)(x >>> 40),
4267 (byte)(x >>> 48),
4268 (byte)(x >>> 56));
4269 }
4270 }
4271
4272 /**
4273 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
4274 * argument which specifies the endianness of the value as stored in memory.
4275 * @param o Java heap object in which the value resides
4276 * @param offset The offset in bytes from the start of the object
4277 * @param x the value to store
4278 * @param bigEndian The endianness of the value
4279 * @throws RuntimeException No defined exceptions are thrown, not even
4280 * {@link NullPointerException}
4281 * @since 9
4282 */
4283 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
4284 putLongUnaligned(o, offset, convEndian(bigEndian, x));
4285 }
4286
4287 /** @see #putLongUnaligned(Object, long, long) */
4288 @IntrinsicCandidate
4289 public final void putIntUnaligned(Object o, long offset, int x) {
4290 if ((offset & 3) == 0) {
4291 putInt(o, offset, x);
4292 } else if ((offset & 1) == 0) {
4293 putIntParts(o, offset,
4294 (short)(x >> 0),
4295 (short)(x >>> 16));
4296 } else {
4297 putIntParts(o, offset,
4298 (byte)(x >>> 0),
4299 (byte)(x >>> 8),
4300 (byte)(x >>> 16),
4301 (byte)(x >>> 24));
4302 }
4303 }
4304 /** @see #putLongUnaligned(Object, long, long, boolean) */
4305 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
4306 putIntUnaligned(o, offset, convEndian(bigEndian, x));
4307 }
4308
4309 /** @see #putLongUnaligned(Object, long, long) */
4310 @IntrinsicCandidate
4311 public final void putShortUnaligned(Object o, long offset, short x) {
4312 if ((offset & 1) == 0) {
4313 putShort(o, offset, x);
4314 } else {
4315 putShortParts(o, offset,
4316 (byte)(x >>> 0),
4317 (byte)(x >>> 8));
4318 }
4319 }
4320 /** @see #putLongUnaligned(Object, long, long, boolean) */
4321 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
4322 putShortUnaligned(o, offset, convEndian(bigEndian, x));
4323 }
4324
4325 /** @see #putLongUnaligned(Object, long, long) */
4326 @IntrinsicCandidate
4327 public final void putCharUnaligned(Object o, long offset, char x) {
4328 putShortUnaligned(o, offset, (short)x);
4329 }
4330 /** @see #putLongUnaligned(Object, long, long, boolean) */
4331 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
4332 putCharUnaligned(o, offset, convEndian(bigEndian, x));
4333 }
4334
4335 private static int pickPos(int top, int pos) { return BIG_ENDIAN ? top - pos : pos; }
4336
4337 // These methods construct integers from bytes. The byte ordering
4338 // is the native endianness of this platform.
4339 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
4340 return ((toUnsignedLong(i0) << pickPos(56, 0))
4341 | (toUnsignedLong(i1) << pickPos(56, 8))
4342 | (toUnsignedLong(i2) << pickPos(56, 16))
4343 | (toUnsignedLong(i3) << pickPos(56, 24))
4344 | (toUnsignedLong(i4) << pickPos(56, 32))
4345 | (toUnsignedLong(i5) << pickPos(56, 40))
4346 | (toUnsignedLong(i6) << pickPos(56, 48))
4347 | (toUnsignedLong(i7) << pickPos(56, 56)));
4348 }
4349 private static long makeLong(short i0, short i1, short i2, short i3) {
4350 return ((toUnsignedLong(i0) << pickPos(48, 0))
4351 | (toUnsignedLong(i1) << pickPos(48, 16))
4352 | (toUnsignedLong(i2) << pickPos(48, 32))
4353 | (toUnsignedLong(i3) << pickPos(48, 48)));
4354 }
4355 private static long makeLong(int i0, int i1) {
4356 return (toUnsignedLong(i0) << pickPos(32, 0))
4357 | (toUnsignedLong(i1) << pickPos(32, 32));
4358 }
4359 private static int makeInt(short i0, short i1) {
4360 return (toUnsignedInt(i0) << pickPos(16, 0))
4361 | (toUnsignedInt(i1) << pickPos(16, 16));
4362 }
4363 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
4364 return ((toUnsignedInt(i0) << pickPos(24, 0))
4365 | (toUnsignedInt(i1) << pickPos(24, 8))
4366 | (toUnsignedInt(i2) << pickPos(24, 16))
4367 | (toUnsignedInt(i3) << pickPos(24, 24)));
4368 }
4369 private static short makeShort(byte i0, byte i1) {
4370 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
4371 | (toUnsignedInt(i1) << pickPos(8, 8)));
4372 }
4373
4374 private static byte pick(byte le, byte be) { return BIG_ENDIAN ? be : le; }
4375 private static short pick(short le, short be) { return BIG_ENDIAN ? be : le; }
4376 private static int pick(int le, int be) { return BIG_ENDIAN ? be : le; }
4377
4378 // These methods write integers to memory from smaller parts
4379 // provided by their caller. The ordering in which these parts
4380 // are written is the native endianness of this platform.
4381 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
4382 putByte(o, offset + 0, pick(i0, i7));
4383 putByte(o, offset + 1, pick(i1, i6));
4384 putByte(o, offset + 2, pick(i2, i5));
4385 putByte(o, offset + 3, pick(i3, i4));
4386 putByte(o, offset + 4, pick(i4, i3));
4387 putByte(o, offset + 5, pick(i5, i2));
4388 putByte(o, offset + 6, pick(i6, i1));
4389 putByte(o, offset + 7, pick(i7, i0));
4390 }
4391 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
4392 putShort(o, offset + 0, pick(i0, i3));
4393 putShort(o, offset + 2, pick(i1, i2));
4394 putShort(o, offset + 4, pick(i2, i1));
4395 putShort(o, offset + 6, pick(i3, i0));
4396 }
4397 private void putLongParts(Object o, long offset, int i0, int i1) {
4398 putInt(o, offset + 0, pick(i0, i1));
4399 putInt(o, offset + 4, pick(i1, i0));
4400 }
4401 private void putIntParts(Object o, long offset, short i0, short i1) {
4402 putShort(o, offset + 0, pick(i0, i1));
4403 putShort(o, offset + 2, pick(i1, i0));
4404 }
4405 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
4406 putByte(o, offset + 0, pick(i0, i3));
4407 putByte(o, offset + 1, pick(i1, i2));
4408 putByte(o, offset + 2, pick(i2, i1));
4409 putByte(o, offset + 3, pick(i3, i0));
4410 }
4411 private void putShortParts(Object o, long offset, byte i0, byte i1) {
4412 putByte(o, offset + 0, pick(i0, i1));
4413 putByte(o, offset + 1, pick(i1, i0));
4414 }
4415
4416 // Zero-extend an integer
4417 private static int toUnsignedInt(byte n) { return n & 0xff; }
4418 private static int toUnsignedInt(short n) { return n & 0xffff; }
4419 private static long toUnsignedLong(byte n) { return n & 0xffl; }
4420 private static long toUnsignedLong(short n) { return n & 0xffffl; }
4421 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
4422
4423 // Maybe byte-reverse an integer
4424 private static char convEndian(boolean big, char n) { return big == BIG_ENDIAN ? n : Character.reverseBytes(n); }
4425 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
4426 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
4427 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
4428
4429
4430
4431 private native long allocateMemory0(long bytes);
4432 private native long reallocateMemory0(long address, long bytes);
4433 private native void freeMemory0(long address);
4434 @IntrinsicCandidate
4435 private native void setMemory0(Object o, long offset, long bytes, byte value);
4436 @IntrinsicCandidate
4437 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
4438 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
4439 private native long objectFieldOffset0(Field f); // throws IAE
4440 private native long knownObjectFieldOffset0(Class<?> c, String name); // error code: -1 not found, -2 static
4441 private native long staticFieldOffset0(Field f); // throws IAE
4442 private native Object staticFieldBase0(Field f); // throws IAE
4443 private native boolean shouldBeInitialized0(Class<?> c);
4444 private native void ensureClassInitialized0(Class<?> c);
4445 private native void notifyStrictStaticAccess0(Class<?> c, long staticFieldOffset, boolean writing);
4446 private native int arrayBaseOffset0(Class<?> arrayClass); // public version returns long to promote correct arithmetic
4447 private native int arrayInstanceBaseOffset0(Object[] array);
4448 private native int arrayIndexScale0(Class<?> arrayClass);
4449 private native int arrayInstanceIndexScale0(Object[] array);
4450 private native long getObjectSize0(Object o);
4451 private native int getLoadAverage0(double[] loadavg, int nelems);
4452
4453
4454 /**
4455 * Invokes the given direct byte buffer's cleaner, if any.
4456 *
4457 * @param directBuffer a direct byte buffer
4458 * @throws NullPointerException if {@code directBuffer} is null
4459 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
4460 * or is a {@link java.nio.Buffer#slice slice}, or is a
4461 * {@link java.nio.Buffer#duplicate duplicate}
4462 */
4463 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
4464 if (!directBuffer.isDirect())
4465 throw new IllegalArgumentException("buffer is non-direct");
4466
4467 DirectBuffer db = (DirectBuffer) directBuffer;
4468 if (db.attachment() != null)
4469 throw new IllegalArgumentException("duplicate or slice");
4470
4471 Cleaner cleaner = db.cleaner();
4472 if (cleaner != null) {
4473 cleaner.clean();
4474 }
4475 }
4476 }