1 /*
2 * Copyright (c) 2000, 2016, 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 java.lang.reflect.Field;
29 import java.security.ProtectionDomain;
30
31 import jdk.internal.reflect.CallerSensitive;
32 import jdk.internal.reflect.Reflection;
33 import jdk.internal.misc.VM;
34
35 import jdk.internal.HotSpotIntrinsicCandidate;
36 import jdk.internal.vm.annotation.ForceInline;
37
38
39 /**
40 * A collection of methods for performing low-level, unsafe operations.
41 * Although the class and all methods are public, use of this class is
42 * limited because only trusted code can obtain instances of it.
43 *
44 * <em>Note:</em> It is the resposibility of the caller to make sure
45 * arguments are checked before methods of this class are
46 * called. While some rudimentary checks are performed on the input,
47 * the checks are best effort and when performance is an overriding
48 * priority, as when methods of this class are optimized by the
49 * runtime compiler, some or all checks (if any) may be elided. Hence,
50 * the caller must not rely on the checks and corresponding
51 * exceptions!
52 *
53 * @author John R. Rose
54 * @see #getUnsafe
55 */
56
57 public final class Unsafe {
58
59 private static native void registerNatives();
60 static {
61 registerNatives();
62 Reflection.registerMethodsToFilter(Unsafe.class, "getUnsafe");
63 }
64
65 private Unsafe() {}
66
67 private static final Unsafe theUnsafe = new Unsafe();
68
69 /**
70 * Provides the caller with the capability of performing unsafe
71 * operations.
72 *
73 * <p>The returned {@code Unsafe} object should be carefully guarded
74 * by the caller, since it can be used to read and write data at arbitrary
75 * memory addresses. It must never be passed to untrusted code.
76 *
77 * <p>Most methods in this class are very low-level, and correspond to a
78 * small number of hardware instructions (on typical machines). Compilers
79 * are encouraged to optimize these methods accordingly.
80 *
81 * <p>Here is a suggested idiom for using unsafe operations:
82 *
83 * <pre> {@code
84 * class MyTrustedClass {
85 * private static final Unsafe unsafe = Unsafe.getUnsafe();
86 * ...
87 * private long myCountAddress = ...;
88 * public int getCount() { return unsafe.getByte(myCountAddress); }
89 * }}</pre>
90 *
91 * (It may assist compilers to make the local variable {@code final}.)
92 *
93 * @throws SecurityException if a security manager exists and its
94 * {@code checkPropertiesAccess} method doesn't allow
95 * access to the system properties.
96 */
97 @CallerSensitive
98 public static Unsafe getUnsafe() {
99 Class<?> caller = Reflection.getCallerClass();
100 if (!VM.isSystemDomainLoader(caller.getClassLoader()))
101 throw new SecurityException("Unsafe");
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 @HotSpotIntrinsicCandidate
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 @HotSpotIntrinsicCandidate
188 public native void putInt(Object o, long offset, int x);
189
190 /**
191 * Fetches a reference value from a given Java variable.
192 * @see #getInt(Object, long)
193 */
194 @HotSpotIntrinsicCandidate
195 public native Object getObject(Object o, long offset);
196
197 /**
198 * Stores a reference value into a given Java variable.
199 * <p>
200 * Unless the reference {@code x} being stored is either null
201 * or matches the field type, the results are undefined.
202 * If the reference {@code o} is non-null, card marks or
203 * other store barriers for that object (if the VM requires them)
204 * are updated.
205 * @see #putInt(Object, long, int)
206 */
207 @HotSpotIntrinsicCandidate
208 public native void putObject(Object o, long offset, Object x);
209
210 /** @see #getInt(Object, long) */
211 @HotSpotIntrinsicCandidate
212 public native boolean getBoolean(Object o, long offset);
213
214 /** @see #putInt(Object, long, int) */
215 @HotSpotIntrinsicCandidate
216 public native void putBoolean(Object o, long offset, boolean x);
217
218 /** @see #getInt(Object, long) */
219 @HotSpotIntrinsicCandidate
220 public native byte getByte(Object o, long offset);
221
222 /** @see #putInt(Object, long, int) */
223 @HotSpotIntrinsicCandidate
224 public native void putByte(Object o, long offset, byte x);
225
226 /** @see #getInt(Object, long) */
227 @HotSpotIntrinsicCandidate
228 public native short getShort(Object o, long offset);
229
230 /** @see #putInt(Object, long, int) */
231 @HotSpotIntrinsicCandidate
232 public native void putShort(Object o, long offset, short x);
233
234 /** @see #getInt(Object, long) */
235 @HotSpotIntrinsicCandidate
236 public native char getChar(Object o, long offset);
237
238 /** @see #putInt(Object, long, int) */
239 @HotSpotIntrinsicCandidate
240 public native void putChar(Object o, long offset, char x);
241
242 /** @see #getInt(Object, long) */
243 @HotSpotIntrinsicCandidate
244 public native long getLong(Object o, long offset);
245
246 /** @see #putInt(Object, long, int) */
247 @HotSpotIntrinsicCandidate
248 public native void putLong(Object o, long offset, long x);
249
250 /** @see #getInt(Object, long) */
251 @HotSpotIntrinsicCandidate
252 public native float getFloat(Object o, long offset);
253
254 /** @see #putInt(Object, long, int) */
255 @HotSpotIntrinsicCandidate
256 public native void putFloat(Object o, long offset, float x);
257
258 /** @see #getInt(Object, long) */
259 @HotSpotIntrinsicCandidate
260 public native double getDouble(Object o, long offset);
261
262 /** @see #putInt(Object, long, int) */
263 @HotSpotIntrinsicCandidate
264 public native void putDouble(Object o, long offset, double x);
265
266 /**
267 * Fetches a native pointer from a given memory address. If the address is
268 * zero, or does not point into a block obtained from {@link
269 * #allocateMemory}, the results are undefined.
270 *
271 * <p>If the native pointer is less than 64 bits wide, it is extended as
272 * an unsigned number to a Java long. The pointer may be indexed by any
273 * given byte offset, simply by adding that offset (as a simple integer) to
274 * the long representing the pointer. The number of bytes actually read
275 * from the target address may be determined by consulting {@link
276 * #addressSize}.
277 *
278 * @see #allocateMemory
279 * @see #getInt(Object, long)
280 */
281 @ForceInline
282 public long getAddress(Object o, long offset) {
283 if (ADDRESS_SIZE == 4) {
284 return Integer.toUnsignedLong(getInt(o, offset));
285 } else {
286 return getLong(o, offset);
287 }
288 }
289
290 /**
291 * Stores a native pointer into a given memory address. If the address is
292 * zero, or does not point into a block obtained from {@link
293 * #allocateMemory}, the results are undefined.
294 *
295 * <p>The number of bytes actually written at the target address may be
296 * determined by consulting {@link #addressSize}.
297 *
298 * @see #allocateMemory
299 * @see #putInt(Object, long, int)
300 */
301 @ForceInline
302 public void putAddress(Object o, long offset, long x) {
303 if (ADDRESS_SIZE == 4) {
304 putInt(o, offset, (int)x);
305 } else {
306 putLong(o, offset, x);
307 }
308 }
309
310 // These read VM internal data.
311
312 /**
313 * Fetches an uncompressed reference value from a given native variable
314 * ignoring the VM's compressed references mode.
315 *
316 * @param address a memory address locating the variable
317 * @return the value fetched from the indicated native variable
318 */
319 public native Object getUncompressedObject(long address);
320
321 /**
322 * Fetches the {@link java.lang.Class} Java mirror for the given native
323 * metaspace {@code Klass} pointer.
324 *
325 * @param metaspaceKlass a native metaspace {@code Klass} pointer
326 * @return the {@link java.lang.Class} Java mirror
327 */
328 public native Class<?> getJavaMirror(long metaspaceKlass);
329
330 /**
331 * Fetches a native metaspace {@code Klass} pointer for the given Java
332 * object.
333 *
334 * @param o Java heap object for which to fetch the class pointer
335 * @return a native metaspace {@code Klass} pointer
336 */
337 public native long getKlassPointer(Object o);
338
339 // These work on values in the C heap.
340
341 /**
342 * Fetches a value from a given memory address. If the address is zero, or
343 * does not point into a block obtained from {@link #allocateMemory}, the
344 * results are undefined.
345 *
346 * @see #allocateMemory
347 */
348 @ForceInline
349 public byte getByte(long address) {
350 return getByte(null, address);
351 }
352
353 /**
354 * Stores a value into a given memory address. If the address is zero, or
355 * does not point into a block obtained from {@link #allocateMemory}, the
356 * results are undefined.
357 *
358 * @see #getByte(long)
359 */
360 @ForceInline
361 public void putByte(long address, byte x) {
362 putByte(null, address, x);
363 }
364
365 /** @see #getByte(long) */
366 @ForceInline
367 public short getShort(long address) {
368 return getShort(null, address);
369 }
370
371 /** @see #putByte(long, byte) */
372 @ForceInline
373 public void putShort(long address, short x) {
374 putShort(null, address, x);
375 }
376
377 /** @see #getByte(long) */
378 @ForceInline
379 public char getChar(long address) {
380 return getChar(null, address);
381 }
382
383 /** @see #putByte(long, byte) */
384 @ForceInline
385 public void putChar(long address, char x) {
386 putChar(null, address, x);
387 }
388
389 /** @see #getByte(long) */
390 @ForceInline
391 public int getInt(long address) {
392 return getInt(null, address);
393 }
394
395 /** @see #putByte(long, byte) */
396 @ForceInline
397 public void putInt(long address, int x) {
398 putInt(null, address, x);
399 }
400
401 /** @see #getByte(long) */
402 @ForceInline
403 public long getLong(long address) {
404 return getLong(null, address);
405 }
406
407 /** @see #putByte(long, byte) */
408 @ForceInline
409 public void putLong(long address, long x) {
410 putLong(null, address, x);
411 }
412
413 /** @see #getByte(long) */
414 @ForceInline
415 public float getFloat(long address) {
416 return getFloat(null, address);
417 }
418
419 /** @see #putByte(long, byte) */
420 @ForceInline
421 public void putFloat(long address, float x) {
422 putFloat(null, address, x);
423 }
424
425 /** @see #getByte(long) */
426 @ForceInline
427 public double getDouble(long address) {
428 return getDouble(null, address);
429 }
430
431 /** @see #putByte(long, byte) */
432 @ForceInline
433 public void putDouble(long address, double x) {
434 putDouble(null, address, x);
435 }
436
437 /** @see #getAddress(Object, long) */
438 @ForceInline
439 public long getAddress(long address) {
440 return getAddress(null, address);
441 }
442
443 /** @see #putAddress(Object, long, long) */
444 @ForceInline
445 public void putAddress(long address, long x) {
446 putAddress(null, address, x);
447 }
448
449
450
451 /// helper methods for validating various types of objects/values
452
453 /**
454 * Create an exception reflecting that some of the input was invalid
455 *
456 * <em>Note:</em> It is the resposibility of the caller to make
457 * sure arguments are checked before the methods are called. While
458 * some rudimentary checks are performed on the input, the checks
459 * are best effort and when performance is an overriding priority,
460 * as when methods of this class are optimized by the runtime
461 * compiler, some or all checks (if any) may be elided. Hence, the
462 * caller must not rely on the checks and corresponding
463 * exceptions!
464 *
465 * @return an exception object
466 */
467 private RuntimeException invalidInput() {
468 return new IllegalArgumentException();
469 }
470
471 /**
472 * Check if a value is 32-bit clean (32 MSB are all zero)
473 *
474 * @param value the 64-bit value to check
475 *
476 * @return true if the value is 32-bit clean
477 */
478 private boolean is32BitClean(long value) {
479 return value >>> 32 == 0;
480 }
481
482 /**
483 * Check the validity of a size (the equivalent of a size_t)
484 *
485 * @throws RuntimeException if the size is invalid
486 * (<em>Note:</em> after optimization, invalid inputs may
487 * go undetected, which will lead to unpredictable
488 * behavior)
489 */
490 private void checkSize(long size) {
491 if (ADDRESS_SIZE == 4) {
492 // Note: this will also check for negative sizes
493 if (!is32BitClean(size)) {
494 throw invalidInput();
495 }
496 } else if (size < 0) {
497 throw invalidInput();
498 }
499 }
500
501 /**
502 * Check the validity of a native address (the equivalent of void*)
503 *
504 * @throws RuntimeException if the address is invalid
505 * (<em>Note:</em> after optimization, invalid inputs may
506 * go undetected, which will lead to unpredictable
507 * behavior)
508 */
509 private void checkNativeAddress(long address) {
510 if (ADDRESS_SIZE == 4) {
511 // Accept both zero and sign extended pointers. A valid
512 // pointer will, after the +1 below, either have produced
513 // the value 0x0 or 0x1. Masking off the low bit allows
514 // for testing against 0.
515 if ((((address >> 32) + 1) & ~1) != 0) {
516 throw invalidInput();
517 }
518 }
519 }
520
521 /**
522 * Check the validity of an offset, relative to a base object
523 *
524 * @param o the base object
525 * @param offset the offset to check
526 *
527 * @throws RuntimeException if the size is invalid
528 * (<em>Note:</em> after optimization, invalid inputs may
529 * go undetected, which will lead to unpredictable
530 * behavior)
531 */
532 private void checkOffset(Object o, long offset) {
533 if (ADDRESS_SIZE == 4) {
534 // Note: this will also check for negative offsets
535 if (!is32BitClean(offset)) {
536 throw invalidInput();
537 }
538 } else if (offset < 0) {
539 throw invalidInput();
540 }
541 }
542
543 /**
544 * Check the validity of a double-register pointer
545 *
546 * Note: This code deliberately does *not* check for NPE for (at
547 * least) three reasons:
548 *
549 * 1) NPE is not just NULL/0 - there is a range of values all
550 * resulting in an NPE, which is not trivial to check for
551 *
552 * 2) It is the responsibility of the callers of Unsafe methods
553 * to verify the input, so throwing an exception here is not really
554 * useful - passing in a NULL pointer is a critical error and the
555 * must not expect an exception to be thrown anyway.
556 *
557 * 3) the actual operations will detect NULL pointers anyway by
558 * means of traps and signals (like SIGSEGV).
559 *
560 * @param o Java heap object, or null
561 * @param offset indication of where the variable resides in a Java heap
562 * object, if any, else a memory address locating the variable
563 * statically
564 *
565 * @throws RuntimeException if the pointer is invalid
566 * (<em>Note:</em> after optimization, invalid inputs may
567 * go undetected, which will lead to unpredictable
568 * behavior)
569 */
570 private void checkPointer(Object o, long offset) {
571 if (o == null) {
572 checkNativeAddress(offset);
573 } else {
574 checkOffset(o, offset);
575 }
576 }
577
578 /**
579 * Check if a type is a primitive array type
580 *
581 * @param c the type to check
582 *
583 * @return true if the type is a primitive array type
584 */
585 private void checkPrimitiveArray(Class<?> c) {
586 Class<?> componentType = c.getComponentType();
587 if (componentType == null || !componentType.isPrimitive()) {
588 throw invalidInput();
589 }
590 }
591
592 /**
593 * Check that a pointer is a valid primitive array type pointer
594 *
595 * Note: pointers off-heap are considered to be primitive arrays
596 *
597 * @throws RuntimeException if the pointer is invalid
598 * (<em>Note:</em> after optimization, invalid inputs may
599 * go undetected, which will lead to unpredictable
600 * behavior)
601 */
602 private void checkPrimitivePointer(Object o, long offset) {
603 checkPointer(o, offset);
604
605 if (o != null) {
606 // If on heap, it it must be a primitive array
607 checkPrimitiveArray(o.getClass());
608 }
609 }
610
611
612 /// wrappers for malloc, realloc, free:
613
614 /**
615 * Allocates a new block of native memory, of the given size in bytes. The
616 * contents of the memory are uninitialized; they will generally be
617 * garbage. The resulting native pointer will never be zero, and will be
618 * aligned for all value types. Dispose of this memory by calling {@link
619 * #freeMemory}, or resize it with {@link #reallocateMemory}.
620 *
621 * <em>Note:</em> It is the resposibility of the caller to make
622 * sure arguments are checked before the methods are called. While
623 * some rudimentary checks are performed on the input, the checks
624 * are best effort and when performance is an overriding priority,
625 * as when methods of this class are optimized by the runtime
626 * compiler, some or all checks (if any) may be elided. Hence, the
627 * caller must not rely on the checks and corresponding
628 * exceptions!
629 *
630 * @throws RuntimeException if the size is negative or too large
631 * for the native size_t type
632 *
633 * @throws OutOfMemoryError if the allocation is refused by the system
634 *
635 * @see #getByte(long)
636 * @see #putByte(long, byte)
637 */
638 public long allocateMemory(long bytes) {
639 allocateMemoryChecks(bytes);
640
641 if (bytes == 0) {
642 return 0;
643 }
644
645 long p = allocateMemory0(bytes);
646 if (p == 0) {
647 throw new OutOfMemoryError();
648 }
649
650 return p;
651 }
652
653 /**
654 * Validate the arguments to allocateMemory
655 *
656 * @throws RuntimeException if the arguments are invalid
657 * (<em>Note:</em> after optimization, invalid inputs may
658 * go undetected, which will lead to unpredictable
659 * behavior)
660 */
661 private void allocateMemoryChecks(long bytes) {
662 checkSize(bytes);
663 }
664
665 /**
666 * Resizes a new block of native memory, to the given size in bytes. The
667 * contents of the new block past the size of the old block are
668 * uninitialized; they will generally be garbage. The resulting native
669 * pointer will be zero if and only if the requested size is zero. The
670 * resulting native pointer will be aligned for all value types. Dispose
671 * of this memory by calling {@link #freeMemory}, or resize it with {@link
672 * #reallocateMemory}. The address passed to this method may be null, in
673 * which case an allocation will be performed.
674 *
675 * <em>Note:</em> It is the resposibility of the caller to make
676 * sure arguments are checked before the methods are called. While
677 * some rudimentary checks are performed on the input, the checks
678 * are best effort and when performance is an overriding priority,
679 * as when methods of this class are optimized by the runtime
680 * compiler, some or all checks (if any) may be elided. Hence, the
681 * caller must not rely on the checks and corresponding
682 * exceptions!
683 *
684 * @throws RuntimeException if the size is negative or too large
685 * for the native size_t type
686 *
687 * @throws OutOfMemoryError if the allocation is refused by the system
688 *
689 * @see #allocateMemory
690 */
691 public long reallocateMemory(long address, long bytes) {
692 reallocateMemoryChecks(address, bytes);
693
694 if (bytes == 0) {
695 freeMemory(address);
696 return 0;
697 }
698
699 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
700 if (p == 0) {
701 throw new OutOfMemoryError();
702 }
703
704 return p;
705 }
706
707 /**
708 * Validate the arguments to reallocateMemory
709 *
710 * @throws RuntimeException if the arguments are invalid
711 * (<em>Note:</em> after optimization, invalid inputs may
712 * go undetected, which will lead to unpredictable
713 * behavior)
714 */
715 private void reallocateMemoryChecks(long address, long bytes) {
716 checkPointer(null, address);
717 checkSize(bytes);
718 }
719
720 /**
721 * Sets all bytes in a given block of memory to a fixed value
722 * (usually zero).
723 *
724 * <p>This method determines a block's base address by means of two parameters,
725 * and so it provides (in effect) a <em>double-register</em> addressing mode,
726 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
727 * the offset supplies an absolute base address.
728 *
729 * <p>The stores are in coherent (atomic) units of a size determined
730 * by the address and length parameters. If the effective address and
731 * length are all even modulo 8, the stores take place in 'long' units.
732 * If the effective address and length are (resp.) even modulo 4 or 2,
733 * the stores take place in units of 'int' or 'short'.
734 *
735 * <em>Note:</em> It is the resposibility of the caller to make
736 * sure arguments are checked before the methods are called. While
737 * some rudimentary checks are performed on the input, the checks
738 * are best effort and when performance is an overriding priority,
739 * as when methods of this class are optimized by the runtime
740 * compiler, some or all checks (if any) may be elided. Hence, the
741 * caller must not rely on the checks and corresponding
742 * exceptions!
743 *
744 * @throws RuntimeException if any of the arguments is invalid
745 *
746 * @since 1.7
747 */
748 public void setMemory(Object o, long offset, long bytes, byte value) {
749 setMemoryChecks(o, offset, bytes, value);
750
751 if (bytes == 0) {
752 return;
753 }
754
755 setMemory0(o, offset, bytes, value);
756 }
757
758 /**
759 * Sets all bytes in a given block of memory to a fixed value
760 * (usually zero). This provides a <em>single-register</em> addressing mode,
761 * as discussed in {@link #getInt(Object,long)}.
762 *
763 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
764 */
765 public void setMemory(long address, long bytes, byte value) {
766 setMemory(null, address, bytes, value);
767 }
768
769 /**
770 * Validate the arguments to setMemory
771 *
772 * @throws RuntimeException if the arguments are invalid
773 * (<em>Note:</em> after optimization, invalid inputs may
774 * go undetected, which will lead to unpredictable
775 * behavior)
776 */
777 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
778 checkPrimitivePointer(o, offset);
779 checkSize(bytes);
780 }
781
782 /**
783 * Sets all bytes in a given block of memory to a copy of another
784 * block.
785 *
786 * <p>This method determines each block's base address by means of two parameters,
787 * and so it provides (in effect) a <em>double-register</em> addressing mode,
788 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
789 * the offset supplies an absolute base address.
790 *
791 * <p>The transfers are in coherent (atomic) units of a size determined
792 * by the address and length parameters. If the effective addresses and
793 * length are all even modulo 8, the transfer takes place in 'long' units.
794 * If the effective addresses and length are (resp.) even modulo 4 or 2,
795 * the transfer takes place in units of 'int' or 'short'.
796 *
797 * <em>Note:</em> It is the resposibility of the caller to make
798 * sure arguments are checked before the methods are called. While
799 * some rudimentary checks are performed on the input, the checks
800 * are best effort and when performance is an overriding priority,
801 * as when methods of this class are optimized by the runtime
802 * compiler, some or all checks (if any) may be elided. Hence, the
803 * caller must not rely on the checks and corresponding
804 * exceptions!
805 *
806 * @throws RuntimeException if any of the arguments is invalid
807 *
808 * @since 1.7
809 */
810 public void copyMemory(Object srcBase, long srcOffset,
811 Object destBase, long destOffset,
812 long bytes) {
813 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
814
815 if (bytes == 0) {
816 return;
817 }
818
819 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
820 }
821
822 /**
823 * Sets all bytes in a given block of memory to a copy of another
824 * block. This provides a <em>single-register</em> addressing mode,
825 * as discussed in {@link #getInt(Object,long)}.
826 *
827 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
828 */
829 public void copyMemory(long srcAddress, long destAddress, long bytes) {
830 copyMemory(null, srcAddress, null, destAddress, bytes);
831 }
832
833 /**
834 * Validate the arguments to copyMemory
835 *
836 * @throws RuntimeException if any of the arguments is invalid
837 * (<em>Note:</em> after optimization, invalid inputs may
838 * go undetected, which will lead to unpredictable
839 * behavior)
840 */
841 private void copyMemoryChecks(Object srcBase, long srcOffset,
842 Object destBase, long destOffset,
843 long bytes) {
844 checkSize(bytes);
845 checkPrimitivePointer(srcBase, srcOffset);
846 checkPrimitivePointer(destBase, destOffset);
847 }
848
849 /**
850 * Copies all elements from one block of memory to another block,
851 * *unconditionally* byte swapping the elements on the fly.
852 *
853 * <p>This method determines each block's base address by means of two parameters,
854 * and so it provides (in effect) a <em>double-register</em> addressing mode,
855 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
856 * the offset supplies an absolute base address.
857 *
858 * <em>Note:</em> It is the resposibility of the caller to make
859 * sure arguments are checked before the methods are called. While
860 * some rudimentary checks are performed on the input, the checks
861 * are best effort and when performance is an overriding priority,
862 * as when methods of this class are optimized by the runtime
863 * compiler, some or all checks (if any) may be elided. Hence, the
864 * caller must not rely on the checks and corresponding
865 * exceptions!
866 *
867 * @throws RuntimeException if any of the arguments is invalid
868 *
869 * @since 9
870 */
871 public void copySwapMemory(Object srcBase, long srcOffset,
872 Object destBase, long destOffset,
873 long bytes, long elemSize) {
874 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
875
876 if (bytes == 0) {
877 return;
878 }
879
880 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
881 }
882
883 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
884 Object destBase, long destOffset,
885 long bytes, long elemSize) {
886 checkSize(bytes);
887
888 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
889 throw invalidInput();
890 }
891 if (bytes % elemSize != 0) {
892 throw invalidInput();
893 }
894
895 checkPrimitivePointer(srcBase, srcOffset);
896 checkPrimitivePointer(destBase, destOffset);
897 }
898
899 /**
900 * Copies all elements from one block of memory to another block, byte swapping the
901 * elements on the fly.
902 *
903 * This provides a <em>single-register</em> addressing mode, as
904 * discussed in {@link #getInt(Object,long)}.
905 *
906 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
907 */
908 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
909 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
910 }
911
912 /**
913 * Disposes of a block of native memory, as obtained from {@link
914 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
915 * this method may be null, in which case no action is taken.
916 *
917 * <em>Note:</em> It is the resposibility of the caller to make
918 * sure arguments are checked before the methods are called. While
919 * some rudimentary checks are performed on the input, the checks
920 * are best effort and when performance is an overriding priority,
921 * as when methods of this class are optimized by the runtime
922 * compiler, some or all checks (if any) may be elided. Hence, the
923 * caller must not rely on the checks and corresponding
924 * exceptions!
925 *
926 * @throws RuntimeException if any of the arguments is invalid
927 *
928 * @see #allocateMemory
929 */
930 public void freeMemory(long address) {
931 freeMemoryChecks(address);
932
933 if (address == 0) {
934 return;
935 }
936
937 freeMemory0(address);
938 }
939
940 /**
941 * Validate the arguments to freeMemory
942 *
943 * @throws RuntimeException if the arguments are invalid
944 * (<em>Note:</em> after optimization, invalid inputs may
945 * go undetected, which will lead to unpredictable
946 * behavior)
947 */
948 private void freeMemoryChecks(long address) {
949 checkPointer(null, address);
950 }
951
952 /// random queries
953
954 /**
955 * This constant differs from all results that will ever be returned from
956 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
957 * or {@link #arrayBaseOffset}.
958 */
959 public static final int INVALID_FIELD_OFFSET = -1;
960
961 /**
962 * Reports the location of a given field in the storage allocation of its
963 * class. Do not expect to perform any sort of arithmetic on this offset;
964 * it is just a cookie which is passed to the unsafe heap memory accessors.
965 *
966 * <p>Any given field will always have the same offset and base, and no
967 * two distinct fields of the same class will ever have the same offset
968 * and base.
969 *
970 * <p>As of 1.4.1, offsets for fields are represented as long values,
971 * although the Sun JVM does not use the most significant 32 bits.
972 * However, JVM implementations which store static fields at absolute
973 * addresses can use long offsets and null base pointers to express
974 * the field locations in a form usable by {@link #getInt(Object,long)}.
975 * Therefore, code which will be ported to such JVMs on 64-bit platforms
976 * must preserve all bits of static field offsets.
977 * @see #getInt(Object, long)
978 */
979 public long objectFieldOffset(Field f) {
980 if (f == null) {
981 throw new NullPointerException();
982 }
983
984 return objectFieldOffset0(f);
985 }
986
987 /**
988 * Reports the location of a given static field, in conjunction with {@link
989 * #staticFieldBase}.
990 * <p>Do not expect to perform any sort of arithmetic on this offset;
991 * it is just a cookie which is passed to the unsafe heap memory accessors.
992 *
993 * <p>Any given field will always have the same offset, and no two distinct
994 * fields of the same class will ever have the same offset.
995 *
996 * <p>As of 1.4.1, offsets for fields are represented as long values,
997 * although the Sun JVM does not use the most significant 32 bits.
998 * It is hard to imagine a JVM technology which needs more than
999 * a few bits to encode an offset within a non-array object,
1000 * However, for consistency with other methods in this class,
1001 * this method reports its result as a long value.
1002 * @see #getInt(Object, long)
1003 */
1004 public long staticFieldOffset(Field f) {
1005 if (f == null) {
1006 throw new NullPointerException();
1007 }
1008
1009 return staticFieldOffset0(f);
1010 }
1011
1012 /**
1013 * Reports the location of a given static field, in conjunction with {@link
1014 * #staticFieldOffset}.
1015 * <p>Fetch the base "Object", if any, with which static fields of the
1016 * given class can be accessed via methods like {@link #getInt(Object,
1017 * long)}. This value may be null. This value may refer to an object
1018 * which is a "cookie", not guaranteed to be a real Object, and it should
1019 * not be used in any way except as argument to the get and put routines in
1020 * this class.
1021 */
1022 public Object staticFieldBase(Field f) {
1023 if (f == null) {
1024 throw new NullPointerException();
1025 }
1026
1027 return staticFieldBase0(f);
1028 }
1029
1030 /**
1031 * Detects if the given class may need to be initialized. This is often
1032 * needed in conjunction with obtaining the static field base of a
1033 * class.
1034 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1035 */
1036 public boolean shouldBeInitialized(Class<?> c) {
1037 if (c == null) {
1038 throw new NullPointerException();
1039 }
1040
1041 return shouldBeInitialized0(c);
1042 }
1043
1044 /**
1045 * Ensures the given class has been initialized. This is often
1046 * needed in conjunction with obtaining the static field base of a
1047 * class.
1048 */
1049 public void ensureClassInitialized(Class<?> c) {
1050 if (c == null) {
1051 throw new NullPointerException();
1052 }
1053
1054 ensureClassInitialized0(c);
1055 }
1056
1057 /**
1058 * Reports the offset of the first element in the storage allocation of a
1059 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1060 * for the same class, you may use that scale factor, together with this
1061 * base offset, to form new offsets to access elements of arrays of the
1062 * given class.
1063 *
1064 * @see #getInt(Object, long)
1065 * @see #putInt(Object, long, int)
1066 */
1067 public int arrayBaseOffset(Class<?> arrayClass) {
1068 if (arrayClass == null) {
1069 throw new NullPointerException();
1070 }
1071
1072 return arrayBaseOffset0(arrayClass);
1073 }
1074
1075
1076 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1077 public static final int ARRAY_BOOLEAN_BASE_OFFSET
1078 = theUnsafe.arrayBaseOffset(boolean[].class);
1079
1080 /** The value of {@code arrayBaseOffset(byte[].class)} */
1081 public static final int ARRAY_BYTE_BASE_OFFSET
1082 = theUnsafe.arrayBaseOffset(byte[].class);
1083
1084 /** The value of {@code arrayBaseOffset(short[].class)} */
1085 public static final int ARRAY_SHORT_BASE_OFFSET
1086 = theUnsafe.arrayBaseOffset(short[].class);
1087
1088 /** The value of {@code arrayBaseOffset(char[].class)} */
1089 public static final int ARRAY_CHAR_BASE_OFFSET
1090 = theUnsafe.arrayBaseOffset(char[].class);
1091
1092 /** The value of {@code arrayBaseOffset(int[].class)} */
1093 public static final int ARRAY_INT_BASE_OFFSET
1094 = theUnsafe.arrayBaseOffset(int[].class);
1095
1096 /** The value of {@code arrayBaseOffset(long[].class)} */
1097 public static final int ARRAY_LONG_BASE_OFFSET
1098 = theUnsafe.arrayBaseOffset(long[].class);
1099
1100 /** The value of {@code arrayBaseOffset(float[].class)} */
1101 public static final int ARRAY_FLOAT_BASE_OFFSET
1102 = theUnsafe.arrayBaseOffset(float[].class);
1103
1104 /** The value of {@code arrayBaseOffset(double[].class)} */
1105 public static final int ARRAY_DOUBLE_BASE_OFFSET
1106 = theUnsafe.arrayBaseOffset(double[].class);
1107
1108 /** The value of {@code arrayBaseOffset(Object[].class)} */
1109 public static final int ARRAY_OBJECT_BASE_OFFSET
1110 = theUnsafe.arrayBaseOffset(Object[].class);
1111
1112 /**
1113 * Reports the scale factor for addressing elements in the storage
1114 * allocation of a given array class. However, arrays of "narrow" types
1115 * will generally not work properly with accessors like {@link
1116 * #getByte(Object, long)}, so the scale factor for such classes is reported
1117 * as zero.
1118 *
1119 * @see #arrayBaseOffset
1120 * @see #getInt(Object, long)
1121 * @see #putInt(Object, long, int)
1122 */
1123 public int arrayIndexScale(Class<?> arrayClass) {
1124 if (arrayClass == null) {
1125 throw new NullPointerException();
1126 }
1127
1128 return arrayIndexScale0(arrayClass);
1129 }
1130
1131
1132 /** The value of {@code arrayIndexScale(boolean[].class)} */
1133 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1134 = theUnsafe.arrayIndexScale(boolean[].class);
1135
1136 /** The value of {@code arrayIndexScale(byte[].class)} */
1137 public static final int ARRAY_BYTE_INDEX_SCALE
1138 = theUnsafe.arrayIndexScale(byte[].class);
1139
1140 /** The value of {@code arrayIndexScale(short[].class)} */
1141 public static final int ARRAY_SHORT_INDEX_SCALE
1142 = theUnsafe.arrayIndexScale(short[].class);
1143
1144 /** The value of {@code arrayIndexScale(char[].class)} */
1145 public static final int ARRAY_CHAR_INDEX_SCALE
1146 = theUnsafe.arrayIndexScale(char[].class);
1147
1148 /** The value of {@code arrayIndexScale(int[].class)} */
1149 public static final int ARRAY_INT_INDEX_SCALE
1150 = theUnsafe.arrayIndexScale(int[].class);
1151
1152 /** The value of {@code arrayIndexScale(long[].class)} */
1153 public static final int ARRAY_LONG_INDEX_SCALE
1154 = theUnsafe.arrayIndexScale(long[].class);
1155
1156 /** The value of {@code arrayIndexScale(float[].class)} */
1157 public static final int ARRAY_FLOAT_INDEX_SCALE
1158 = theUnsafe.arrayIndexScale(float[].class);
1159
1160 /** The value of {@code arrayIndexScale(double[].class)} */
1161 public static final int ARRAY_DOUBLE_INDEX_SCALE
1162 = theUnsafe.arrayIndexScale(double[].class);
1163
1164 /** The value of {@code arrayIndexScale(Object[].class)} */
1165 public static final int ARRAY_OBJECT_INDEX_SCALE
1166 = theUnsafe.arrayIndexScale(Object[].class);
1167
1168 /**
1169 * Reports the size in bytes of a native pointer, as stored via {@link
1170 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1171 * other primitive types (as stored in native memory blocks) is determined
1172 * fully by their information content.
1173 */
1174 public int addressSize() {
1175 return ADDRESS_SIZE;
1176 }
1177
1178 /** The value of {@code addressSize()} */
1179 public static final int ADDRESS_SIZE = theUnsafe.addressSize0();
1180
1181 /**
1182 * Reports the size in bytes of a native memory page (whatever that is).
1183 * This value will always be a power of two.
1184 */
1185 public native int pageSize();
1186
1187
1188 /// random trusted operations from JNI:
1189
1190 /**
1191 * Tells the VM to define a class, without security checks. By default, the
1192 * class loader and protection domain come from the caller's class.
1193 */
1194 public Class<?> defineClass(String name, byte[] b, int off, int len,
1195 ClassLoader loader,
1196 ProtectionDomain protectionDomain) {
1197 if (b == null) {
1198 throw new NullPointerException();
1199 }
1200 if (len < 0) {
1201 throw new ArrayIndexOutOfBoundsException();
1202 }
1203
1204 return defineClass0(name, b, off, len, loader, protectionDomain);
1205 }
1206
1207 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1208 ClassLoader loader,
1209 ProtectionDomain protectionDomain);
1210
1211 /**
1212 * Defines a class but does not make it known to the class loader or system dictionary.
1213 * <p>
1214 * For each CP entry, the corresponding CP patch must either be null or have
1215 * the a format that matches its tag:
1216 * <ul>
1217 * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang
1218 * <li>Utf8: a string (must have suitable syntax if used as signature or name)
1219 * <li>Class: any java.lang.Class object
1220 * <li>String: any object (not just a java.lang.String)
1221 * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments
1222 * </ul>
1223 * @param hostClass context for linkage, access control, protection domain, and class loader
1224 * @param data bytes of a class file
1225 * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data
1226 */
1227 public Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches) {
1228 if (hostClass == null || data == null) {
1229 throw new NullPointerException();
1230 }
1231
1232 return defineAnonymousClass0(hostClass, data, cpPatches);
1233 }
1234
1235 /**
1236 * Allocates an instance but does not run any constructor.
1237 * Initializes the class if it has not yet been.
1238 */
1239 @HotSpotIntrinsicCandidate
1240 public native Object allocateInstance(Class<?> cls)
1241 throws InstantiationException;
1242
1243 /**
1244 * Allocates an array of a given type, but does not do zeroing.
1245 * <p>
1246 * This method should only be used in the very rare cases where a high-performance code
1247 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1248 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1249 * <p>
1250 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1251 * before allowing untrusted code, or code in other threads, to observe the reference
1252 * to the newly allocated array. In addition, the publication of the array reference must be
1253 * safe according to the Java Memory Model requirements.
1254 * <p>
1255 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1256 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1257 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1258 * or issuing a {@link #storeFence} before publishing the reference.
1259 * <p>
1260 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1261 * elements that could break heap integrity.
1262 *
1263 * @param componentType array component type to allocate
1264 * @param length array size to allocate
1265 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1266 * or the length is negative
1267 */
1268 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1269 if (componentType == null) {
1270 throw new IllegalArgumentException("Component type is null");
1271 }
1272 if (!componentType.isPrimitive()) {
1273 throw new IllegalArgumentException("Component type is not primitive");
1274 }
1275 if (length < 0) {
1276 throw new IllegalArgumentException("Negative length");
1277 }
1278 return allocateUninitializedArray0(componentType, length);
1279 }
1280
1281 @HotSpotIntrinsicCandidate
1282 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1283 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1284 // return the zeroed arrays.
1285 if (componentType == byte.class) return new byte[length];
1286 if (componentType == boolean.class) return new boolean[length];
1287 if (componentType == short.class) return new short[length];
1288 if (componentType == char.class) return new char[length];
1289 if (componentType == int.class) return new int[length];
1290 if (componentType == float.class) return new float[length];
1291 if (componentType == long.class) return new long[length];
1292 if (componentType == double.class) return new double[length];
1293 return null;
1294 }
1295
1296 /** Throws the exception without telling the verifier. */
1297 public native void throwException(Throwable ee);
1298
1299 /**
1300 * Atomically updates Java variable to {@code x} if it is currently
1301 * holding {@code expected}.
1302 *
1303 * <p>This operation has memory semantics of a {@code volatile} read
1304 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1305 *
1306 * @return {@code true} if successful
1307 */
1308 @HotSpotIntrinsicCandidate
1309 public final native boolean compareAndSwapObject(Object o, long offset,
1310 Object expected,
1311 Object x);
1312
1313 @HotSpotIntrinsicCandidate
1314 public final native Object compareAndExchangeObjectVolatile(Object o, long offset,
1315 Object expected,
1316 Object x);
1317
1318 @HotSpotIntrinsicCandidate
1319 public final Object compareAndExchangeObjectAcquire(Object o, long offset,
1320 Object expected,
1321 Object x) {
1322 return compareAndExchangeObjectVolatile(o, offset, expected, x);
1323 }
1324
1325 @HotSpotIntrinsicCandidate
1326 public final Object compareAndExchangeObjectRelease(Object o, long offset,
1327 Object expected,
1328 Object x) {
1329 return compareAndExchangeObjectVolatile(o, offset, expected, x);
1330 }
1331
1332 @HotSpotIntrinsicCandidate
1333 public final boolean weakCompareAndSwapObject(Object o, long offset,
1334 Object expected,
1335 Object x) {
1336 return compareAndSwapObject(o, offset, expected, x);
1337 }
1338
1339 @HotSpotIntrinsicCandidate
1340 public final boolean weakCompareAndSwapObjectAcquire(Object o, long offset,
1341 Object expected,
1342 Object x) {
1343 return compareAndSwapObject(o, offset, expected, x);
1344 }
1345
1346 @HotSpotIntrinsicCandidate
1347 public final boolean weakCompareAndSwapObjectRelease(Object o, long offset,
1348 Object expected,
1349 Object x) {
1350 return compareAndSwapObject(o, offset, expected, x);
1351 }
1352
1353 @HotSpotIntrinsicCandidate
1354 public final boolean weakCompareAndSwapObjectVolatile(Object o, long offset,
1355 Object expected,
1356 Object x) {
1357 return compareAndSwapObject(o, offset, expected, x);
1358 }
1359
1360 /**
1361 * Atomically updates Java variable to {@code x} if it is currently
1362 * holding {@code expected}.
1363 *
1364 * <p>This operation has memory semantics of a {@code volatile} read
1365 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1366 *
1367 * @return {@code true} if successful
1368 */
1369 @HotSpotIntrinsicCandidate
1370 public final native boolean compareAndSwapInt(Object o, long offset,
1371 int expected,
1372 int x);
1373
1374 @HotSpotIntrinsicCandidate
1375 public final native int compareAndExchangeIntVolatile(Object o, long offset,
1376 int expected,
1377 int x);
1378
1379 @HotSpotIntrinsicCandidate
1380 public final int compareAndExchangeIntAcquire(Object o, long offset,
1381 int expected,
1382 int x) {
1383 return compareAndExchangeIntVolatile(o, offset, expected, x);
1384 }
1385
1386 @HotSpotIntrinsicCandidate
1387 public final int compareAndExchangeIntRelease(Object o, long offset,
1388 int expected,
1389 int x) {
1390 return compareAndExchangeIntVolatile(o, offset, expected, x);
1391 }
1392
1393 @HotSpotIntrinsicCandidate
1394 public final boolean weakCompareAndSwapInt(Object o, long offset,
1395 int expected,
1396 int x) {
1397 return compareAndSwapInt(o, offset, expected, x);
1398 }
1399
1400 @HotSpotIntrinsicCandidate
1401 public final boolean weakCompareAndSwapIntAcquire(Object o, long offset,
1402 int expected,
1403 int x) {
1404 return compareAndSwapInt(o, offset, expected, x);
1405 }
1406
1407 @HotSpotIntrinsicCandidate
1408 public final boolean weakCompareAndSwapIntRelease(Object o, long offset,
1409 int expected,
1410 int x) {
1411 return compareAndSwapInt(o, offset, expected, x);
1412 }
1413
1414 @HotSpotIntrinsicCandidate
1415 public final boolean weakCompareAndSwapIntVolatile(Object o, long offset,
1416 int expected,
1417 int x) {
1418 return compareAndSwapInt(o, offset, expected, x);
1419 }
1420
1421 @HotSpotIntrinsicCandidate
1422 public final byte compareAndExchangeByteVolatile(Object o, long offset,
1423 byte expected,
1424 byte x) {
1425 long wordOffset = offset & ~3;
1426 int shift = (int) (offset & 3) << 3;
1427 if (BE) {
1428 shift = 24 - shift;
1429 }
1430 int mask = 0xFF << shift;
1431 int maskedExpected = (expected & 0xFF) << shift;
1432 int maskedX = (x & 0xFF) << shift;
1433 int fullWord;
1434 do {
1435 fullWord = getIntVolatile(o, wordOffset);
1436 if ((fullWord & mask) != maskedExpected)
1437 return (byte) ((fullWord & mask) >> shift);
1438 } while (!weakCompareAndSwapIntVolatile(o, wordOffset,
1439 fullWord, (fullWord & ~mask) | maskedX));
1440 return expected;
1441 }
1442
1443 @HotSpotIntrinsicCandidate
1444 public final boolean compareAndSwapByte(Object o, long offset,
1445 byte expected,
1446 byte x) {
1447 return compareAndExchangeByteVolatile(o, offset, expected, x) == expected;
1448 }
1449
1450 @HotSpotIntrinsicCandidate
1451 public final boolean weakCompareAndSwapByteVolatile(Object o, long offset,
1452 byte expected,
1453 byte x) {
1454 return compareAndSwapByte(o, offset, expected, x);
1455 }
1456
1457 @HotSpotIntrinsicCandidate
1458 public final boolean weakCompareAndSwapByteAcquire(Object o, long offset,
1459 byte expected,
1460 byte x) {
1461 return weakCompareAndSwapByteVolatile(o, offset, expected, x);
1462 }
1463
1464 @HotSpotIntrinsicCandidate
1465 public final boolean weakCompareAndSwapByteRelease(Object o, long offset,
1466 byte expected,
1467 byte x) {
1468 return weakCompareAndSwapByteVolatile(o, offset, expected, x);
1469 }
1470
1471 @HotSpotIntrinsicCandidate
1472 public final boolean weakCompareAndSwapByte(Object o, long offset,
1473 byte expected,
1474 byte x) {
1475 return weakCompareAndSwapByteVolatile(o, offset, expected, x);
1476 }
1477
1478 @HotSpotIntrinsicCandidate
1479 public final byte compareAndExchangeByteAcquire(Object o, long offset,
1480 byte expected,
1481 byte x) {
1482 return compareAndExchangeByteVolatile(o, offset, expected, x);
1483 }
1484
1485 @HotSpotIntrinsicCandidate
1486 public final byte compareAndExchangeByteRelease(Object o, long offset,
1487 byte expected,
1488 byte x) {
1489 return compareAndExchangeByteVolatile(o, offset, expected, x);
1490 }
1491
1492 @HotSpotIntrinsicCandidate
1493 public final short compareAndExchangeShortVolatile(Object o, long offset,
1494 short expected,
1495 short x) {
1496 if ((offset & 3) == 3) {
1497 throw new IllegalArgumentException("Update spans the word, not supported");
1498 }
1499 long wordOffset = offset & ~3;
1500 int shift = (int) (offset & 3) << 3;
1501 if (BE) {
1502 shift = 16 - shift;
1503 }
1504 int mask = 0xFFFF << shift;
1505 int maskedExpected = (expected & 0xFFFF) << shift;
1506 int maskedX = (x & 0xFFFF) << shift;
1507 int fullWord;
1508 do {
1509 fullWord = getIntVolatile(o, wordOffset);
1510 if ((fullWord & mask) != maskedExpected) {
1511 return (short) ((fullWord & mask) >> shift);
1512 }
1513 } while (!weakCompareAndSwapIntVolatile(o, wordOffset,
1514 fullWord, (fullWord & ~mask) | maskedX));
1515 return expected;
1516 }
1517
1518 @HotSpotIntrinsicCandidate
1519 public final boolean compareAndSwapShort(Object o, long offset,
1520 short expected,
1521 short x) {
1522 return compareAndExchangeShortVolatile(o, offset, expected, x) == expected;
1523 }
1524
1525 @HotSpotIntrinsicCandidate
1526 public final boolean weakCompareAndSwapShortVolatile(Object o, long offset,
1527 short expected,
1528 short x) {
1529 return compareAndSwapShort(o, offset, expected, x);
1530 }
1531
1532 @HotSpotIntrinsicCandidate
1533 public final boolean weakCompareAndSwapShortAcquire(Object o, long offset,
1534 short expected,
1535 short x) {
1536 return weakCompareAndSwapShortVolatile(o, offset, expected, x);
1537 }
1538
1539 @HotSpotIntrinsicCandidate
1540 public final boolean weakCompareAndSwapShortRelease(Object o, long offset,
1541 short expected,
1542 short x) {
1543 return weakCompareAndSwapShortVolatile(o, offset, expected, x);
1544 }
1545
1546 @HotSpotIntrinsicCandidate
1547 public final boolean weakCompareAndSwapShort(Object o, long offset,
1548 short expected,
1549 short x) {
1550 return weakCompareAndSwapShortVolatile(o, offset, expected, x);
1551 }
1552
1553
1554 @HotSpotIntrinsicCandidate
1555 public final short compareAndExchangeShortAcquire(Object o, long offset,
1556 short expected,
1557 short x) {
1558 return compareAndExchangeShortVolatile(o, offset, expected, x);
1559 }
1560
1561 @HotSpotIntrinsicCandidate
1562 public final short compareAndExchangeShortRelease(Object o, long offset,
1563 short expected,
1564 short x) {
1565 return compareAndExchangeShortVolatile(o, offset, expected, x);
1566 }
1567
1568 @ForceInline
1569 private char s2c(short s) {
1570 return (char) s;
1571 }
1572
1573 @ForceInline
1574 private short c2s(char s) {
1575 return (short) s;
1576 }
1577
1578 @ForceInline
1579 public final boolean compareAndSwapChar(Object o, long offset,
1580 char expected,
1581 char x) {
1582 return compareAndSwapShort(o, offset, c2s(expected), c2s(x));
1583 }
1584
1585 @ForceInline
1586 public final char compareAndExchangeCharVolatile(Object o, long offset,
1587 char expected,
1588 char x) {
1589 return s2c(compareAndExchangeShortVolatile(o, offset, c2s(expected), c2s(x)));
1590 }
1591
1592 @ForceInline
1593 public final char compareAndExchangeCharAcquire(Object o, long offset,
1594 char expected,
1595 char x) {
1596 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
1597 }
1598
1599 @ForceInline
1600 public final char compareAndExchangeCharRelease(Object o, long offset,
1601 char expected,
1602 char x) {
1603 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
1604 }
1605
1606 @ForceInline
1607 public final boolean weakCompareAndSwapCharVolatile(Object o, long offset,
1608 char expected,
1609 char x) {
1610 return weakCompareAndSwapShortVolatile(o, offset, c2s(expected), c2s(x));
1611 }
1612
1613 @ForceInline
1614 public final boolean weakCompareAndSwapCharAcquire(Object o, long offset,
1615 char expected,
1616 char x) {
1617 return weakCompareAndSwapShortAcquire(o, offset, c2s(expected), c2s(x));
1618 }
1619
1620 @ForceInline
1621 public final boolean weakCompareAndSwapCharRelease(Object o, long offset,
1622 char expected,
1623 char x) {
1624 return weakCompareAndSwapShortRelease(o, offset, c2s(expected), c2s(x));
1625 }
1626
1627 @ForceInline
1628 public final boolean weakCompareAndSwapChar(Object o, long offset,
1629 char expected,
1630 char x) {
1631 return weakCompareAndSwapShort(o, offset, c2s(expected), c2s(x));
1632 }
1633
1634 @ForceInline
1635 private boolean byte2bool(byte b) {
1636 return b > 0;
1637 }
1638
1639 @ForceInline
1640 private byte bool2byte(boolean b) {
1641 return b ? (byte)1 : (byte)0;
1642 }
1643
1644 @ForceInline
1645 public final boolean compareAndSwapBoolean(Object o, long offset,
1646 boolean expected,
1647 boolean x) {
1648 return compareAndSwapByte(o, offset, bool2byte(expected), bool2byte(x));
1649 }
1650
1651 @ForceInline
1652 public final boolean compareAndExchangeBooleanVolatile(Object o, long offset,
1653 boolean expected,
1654 boolean x) {
1655 return byte2bool(compareAndExchangeByteVolatile(o, offset, bool2byte(expected), bool2byte(x)));
1656 }
1657
1658 @ForceInline
1659 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
1660 boolean expected,
1661 boolean x) {
1662 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
1663 }
1664
1665 @ForceInline
1666 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
1667 boolean expected,
1668 boolean x) {
1669 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
1670 }
1671
1672 @ForceInline
1673 public final boolean weakCompareAndSwapBooleanVolatile(Object o, long offset,
1674 boolean expected,
1675 boolean x) {
1676 return weakCompareAndSwapByteVolatile(o, offset, bool2byte(expected), bool2byte(x));
1677 }
1678
1679 @ForceInline
1680 public final boolean weakCompareAndSwapBooleanAcquire(Object o, long offset,
1681 boolean expected,
1682 boolean x) {
1683 return weakCompareAndSwapByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
1684 }
1685
1686 @ForceInline
1687 public final boolean weakCompareAndSwapBooleanRelease(Object o, long offset,
1688 boolean expected,
1689 boolean x) {
1690 return weakCompareAndSwapByteRelease(o, offset, bool2byte(expected), bool2byte(x));
1691 }
1692
1693 @ForceInline
1694 public final boolean weakCompareAndSwapBoolean(Object o, long offset,
1695 boolean expected,
1696 boolean x) {
1697 return weakCompareAndSwapByte(o, offset, bool2byte(expected), bool2byte(x));
1698 }
1699
1700 /**
1701 * Atomically updates Java variable to {@code x} if it is currently
1702 * holding {@code expected}.
1703 *
1704 * <p>This operation has memory semantics of a {@code volatile} read
1705 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1706 *
1707 * @return {@code true} if successful
1708 */
1709 @HotSpotIntrinsicCandidate
1710 public final native boolean compareAndSwapLong(Object o, long offset,
1711 long expected,
1712 long x);
1713
1714 @HotSpotIntrinsicCandidate
1715 public final native long compareAndExchangeLongVolatile(Object o, long offset,
1716 long expected,
1717 long x);
1718
1719 @HotSpotIntrinsicCandidate
1720 public final long compareAndExchangeLongAcquire(Object o, long offset,
1721 long expected,
1722 long x) {
1723 return compareAndExchangeLongVolatile(o, offset, expected, x);
1724 }
1725
1726 @HotSpotIntrinsicCandidate
1727 public final long compareAndExchangeLongRelease(Object o, long offset,
1728 long expected,
1729 long x) {
1730 return compareAndExchangeLongVolatile(o, offset, expected, x);
1731 }
1732
1733 @HotSpotIntrinsicCandidate
1734 public final boolean weakCompareAndSwapLong(Object o, long offset,
1735 long expected,
1736 long x) {
1737 return compareAndSwapLong(o, offset, expected, x);
1738 }
1739
1740 @HotSpotIntrinsicCandidate
1741 public final boolean weakCompareAndSwapLongAcquire(Object o, long offset,
1742 long expected,
1743 long x) {
1744 return compareAndSwapLong(o, offset, expected, x);
1745 }
1746
1747 @HotSpotIntrinsicCandidate
1748 public final boolean weakCompareAndSwapLongRelease(Object o, long offset,
1749 long expected,
1750 long x) {
1751 return compareAndSwapLong(o, offset, expected, x);
1752 }
1753
1754 @HotSpotIntrinsicCandidate
1755 public final boolean weakCompareAndSwapLongVolatile(Object o, long offset,
1756 long expected,
1757 long x) {
1758 return compareAndSwapLong(o, offset, expected, x);
1759 }
1760
1761 /**
1762 * Fetches a reference value from a given Java variable, with volatile
1763 * load semantics. Otherwise identical to {@link #getObject(Object, long)}
1764 */
1765 @HotSpotIntrinsicCandidate
1766 public native Object getObjectVolatile(Object o, long offset);
1767
1768 /**
1769 * Stores a reference value into a given Java variable, with
1770 * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)}
1771 */
1772 @HotSpotIntrinsicCandidate
1773 public native void putObjectVolatile(Object o, long offset, Object x);
1774
1775 /** Volatile version of {@link #getInt(Object, long)} */
1776 @HotSpotIntrinsicCandidate
1777 public native int getIntVolatile(Object o, long offset);
1778
1779 /** Volatile version of {@link #putInt(Object, long, int)} */
1780 @HotSpotIntrinsicCandidate
1781 public native void putIntVolatile(Object o, long offset, int x);
1782
1783 /** Volatile version of {@link #getBoolean(Object, long)} */
1784 @HotSpotIntrinsicCandidate
1785 public native boolean getBooleanVolatile(Object o, long offset);
1786
1787 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
1788 @HotSpotIntrinsicCandidate
1789 public native void putBooleanVolatile(Object o, long offset, boolean x);
1790
1791 /** Volatile version of {@link #getByte(Object, long)} */
1792 @HotSpotIntrinsicCandidate
1793 public native byte getByteVolatile(Object o, long offset);
1794
1795 /** Volatile version of {@link #putByte(Object, long, byte)} */
1796 @HotSpotIntrinsicCandidate
1797 public native void putByteVolatile(Object o, long offset, byte x);
1798
1799 /** Volatile version of {@link #getShort(Object, long)} */
1800 @HotSpotIntrinsicCandidate
1801 public native short getShortVolatile(Object o, long offset);
1802
1803 /** Volatile version of {@link #putShort(Object, long, short)} */
1804 @HotSpotIntrinsicCandidate
1805 public native void putShortVolatile(Object o, long offset, short x);
1806
1807 /** Volatile version of {@link #getChar(Object, long)} */
1808 @HotSpotIntrinsicCandidate
1809 public native char getCharVolatile(Object o, long offset);
1810
1811 /** Volatile version of {@link #putChar(Object, long, char)} */
1812 @HotSpotIntrinsicCandidate
1813 public native void putCharVolatile(Object o, long offset, char x);
1814
1815 /** Volatile version of {@link #getLong(Object, long)} */
1816 @HotSpotIntrinsicCandidate
1817 public native long getLongVolatile(Object o, long offset);
1818
1819 /** Volatile version of {@link #putLong(Object, long, long)} */
1820 @HotSpotIntrinsicCandidate
1821 public native void putLongVolatile(Object o, long offset, long x);
1822
1823 /** Volatile version of {@link #getFloat(Object, long)} */
1824 @HotSpotIntrinsicCandidate
1825 public native float getFloatVolatile(Object o, long offset);
1826
1827 /** Volatile version of {@link #putFloat(Object, long, float)} */
1828 @HotSpotIntrinsicCandidate
1829 public native void putFloatVolatile(Object o, long offset, float x);
1830
1831 /** Volatile version of {@link #getDouble(Object, long)} */
1832 @HotSpotIntrinsicCandidate
1833 public native double getDoubleVolatile(Object o, long offset);
1834
1835 /** Volatile version of {@link #putDouble(Object, long, double)} */
1836 @HotSpotIntrinsicCandidate
1837 public native void putDoubleVolatile(Object o, long offset, double x);
1838
1839
1840
1841 /** Acquire version of {@link #getObjectVolatile(Object, long)} */
1842 @HotSpotIntrinsicCandidate
1843 public final Object getObjectAcquire(Object o, long offset) {
1844 return getObjectVolatile(o, offset);
1845 }
1846
1847 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
1848 @HotSpotIntrinsicCandidate
1849 public final boolean getBooleanAcquire(Object o, long offset) {
1850 return getBooleanVolatile(o, offset);
1851 }
1852
1853 /** Acquire version of {@link #getByteVolatile(Object, long)} */
1854 @HotSpotIntrinsicCandidate
1855 public final byte getByteAcquire(Object o, long offset) {
1856 return getByteVolatile(o, offset);
1857 }
1858
1859 /** Acquire version of {@link #getShortVolatile(Object, long)} */
1860 @HotSpotIntrinsicCandidate
1861 public final short getShortAcquire(Object o, long offset) {
1862 return getShortVolatile(o, offset);
1863 }
1864
1865 /** Acquire version of {@link #getCharVolatile(Object, long)} */
1866 @HotSpotIntrinsicCandidate
1867 public final char getCharAcquire(Object o, long offset) {
1868 return getCharVolatile(o, offset);
1869 }
1870
1871 /** Acquire version of {@link #getIntVolatile(Object, long)} */
1872 @HotSpotIntrinsicCandidate
1873 public final int getIntAcquire(Object o, long offset) {
1874 return getIntVolatile(o, offset);
1875 }
1876
1877 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
1878 @HotSpotIntrinsicCandidate
1879 public final float getFloatAcquire(Object o, long offset) {
1880 return getFloatVolatile(o, offset);
1881 }
1882
1883 /** Acquire version of {@link #getLongVolatile(Object, long)} */
1884 @HotSpotIntrinsicCandidate
1885 public final long getLongAcquire(Object o, long offset) {
1886 return getLongVolatile(o, offset);
1887 }
1888
1889 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
1890 @HotSpotIntrinsicCandidate
1891 public final double getDoubleAcquire(Object o, long offset) {
1892 return getDoubleVolatile(o, offset);
1893 }
1894
1895 /*
1896 * Versions of {@link #putObjectVolatile(Object, long, Object)}
1897 * that do not guarantee immediate visibility of the store to
1898 * other threads. This method is generally only useful if the
1899 * underlying field is a Java volatile (or if an array cell, one
1900 * that is otherwise only accessed using volatile accesses).
1901 *
1902 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
1903 */
1904
1905 /** Release version of {@link #putObjectVolatile(Object, long, Object)} */
1906 @HotSpotIntrinsicCandidate
1907 public final void putObjectRelease(Object o, long offset, Object x) {
1908 putObjectVolatile(o, offset, x);
1909 }
1910
1911 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
1912 @HotSpotIntrinsicCandidate
1913 public final void putBooleanRelease(Object o, long offset, boolean x) {
1914 putBooleanVolatile(o, offset, x);
1915 }
1916
1917 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
1918 @HotSpotIntrinsicCandidate
1919 public final void putByteRelease(Object o, long offset, byte x) {
1920 putByteVolatile(o, offset, x);
1921 }
1922
1923 /** Release version of {@link #putShortVolatile(Object, long, short)} */
1924 @HotSpotIntrinsicCandidate
1925 public final void putShortRelease(Object o, long offset, short x) {
1926 putShortVolatile(o, offset, x);
1927 }
1928
1929 /** Release version of {@link #putCharVolatile(Object, long, char)} */
1930 @HotSpotIntrinsicCandidate
1931 public final void putCharRelease(Object o, long offset, char x) {
1932 putCharVolatile(o, offset, x);
1933 }
1934
1935 /** Release version of {@link #putIntVolatile(Object, long, int)} */
1936 @HotSpotIntrinsicCandidate
1937 public final void putIntRelease(Object o, long offset, int x) {
1938 putIntVolatile(o, offset, x);
1939 }
1940
1941 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
1942 @HotSpotIntrinsicCandidate
1943 public final void putFloatRelease(Object o, long offset, float x) {
1944 putFloatVolatile(o, offset, x);
1945 }
1946
1947 /** Release version of {@link #putLongVolatile(Object, long, long)} */
1948 @HotSpotIntrinsicCandidate
1949 public final void putLongRelease(Object o, long offset, long x) {
1950 putLongVolatile(o, offset, x);
1951 }
1952
1953 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
1954 @HotSpotIntrinsicCandidate
1955 public final void putDoubleRelease(Object o, long offset, double x) {
1956 putDoubleVolatile(o, offset, x);
1957 }
1958
1959 // ------------------------------ Opaque --------------------------------------
1960
1961 /** Opaque version of {@link #getObjectVolatile(Object, long)} */
1962 @HotSpotIntrinsicCandidate
1963 public final Object getObjectOpaque(Object o, long offset) {
1964 return getObjectVolatile(o, offset);
1965 }
1966
1967 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
1968 @HotSpotIntrinsicCandidate
1969 public final boolean getBooleanOpaque(Object o, long offset) {
1970 return getBooleanVolatile(o, offset);
1971 }
1972
1973 /** Opaque version of {@link #getByteVolatile(Object, long)} */
1974 @HotSpotIntrinsicCandidate
1975 public final byte getByteOpaque(Object o, long offset) {
1976 return getByteVolatile(o, offset);
1977 }
1978
1979 /** Opaque version of {@link #getShortVolatile(Object, long)} */
1980 @HotSpotIntrinsicCandidate
1981 public final short getShortOpaque(Object o, long offset) {
1982 return getShortVolatile(o, offset);
1983 }
1984
1985 /** Opaque version of {@link #getCharVolatile(Object, long)} */
1986 @HotSpotIntrinsicCandidate
1987 public final char getCharOpaque(Object o, long offset) {
1988 return getCharVolatile(o, offset);
1989 }
1990
1991 /** Opaque version of {@link #getIntVolatile(Object, long)} */
1992 @HotSpotIntrinsicCandidate
1993 public final int getIntOpaque(Object o, long offset) {
1994 return getIntVolatile(o, offset);
1995 }
1996
1997 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
1998 @HotSpotIntrinsicCandidate
1999 public final float getFloatOpaque(Object o, long offset) {
2000 return getFloatVolatile(o, offset);
2001 }
2002
2003 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2004 @HotSpotIntrinsicCandidate
2005 public final long getLongOpaque(Object o, long offset) {
2006 return getLongVolatile(o, offset);
2007 }
2008
2009 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2010 @HotSpotIntrinsicCandidate
2011 public final double getDoubleOpaque(Object o, long offset) {
2012 return getDoubleVolatile(o, offset);
2013 }
2014
2015 /** Opaque version of {@link #putObjectVolatile(Object, long, Object)} */
2016 @HotSpotIntrinsicCandidate
2017 public final void putObjectOpaque(Object o, long offset, Object x) {
2018 putObjectVolatile(o, offset, x);
2019 }
2020
2021 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2022 @HotSpotIntrinsicCandidate
2023 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2024 putBooleanVolatile(o, offset, x);
2025 }
2026
2027 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2028 @HotSpotIntrinsicCandidate
2029 public final void putByteOpaque(Object o, long offset, byte x) {
2030 putByteVolatile(o, offset, x);
2031 }
2032
2033 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2034 @HotSpotIntrinsicCandidate
2035 public final void putShortOpaque(Object o, long offset, short x) {
2036 putShortVolatile(o, offset, x);
2037 }
2038
2039 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2040 @HotSpotIntrinsicCandidate
2041 public final void putCharOpaque(Object o, long offset, char x) {
2042 putCharVolatile(o, offset, x);
2043 }
2044
2045 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2046 @HotSpotIntrinsicCandidate
2047 public final void putIntOpaque(Object o, long offset, int x) {
2048 putIntVolatile(o, offset, x);
2049 }
2050
2051 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2052 @HotSpotIntrinsicCandidate
2053 public final void putFloatOpaque(Object o, long offset, float x) {
2054 putFloatVolatile(o, offset, x);
2055 }
2056
2057 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2058 @HotSpotIntrinsicCandidate
2059 public final void putLongOpaque(Object o, long offset, long x) {
2060 putLongVolatile(o, offset, x);
2061 }
2062
2063 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2064 @HotSpotIntrinsicCandidate
2065 public final void putDoubleOpaque(Object o, long offset, double x) {
2066 putDoubleVolatile(o, offset, x);
2067 }
2068
2069 /**
2070 * Unblocks the given thread blocked on {@code park}, or, if it is
2071 * not blocked, causes the subsequent call to {@code park} not to
2072 * block. Note: this operation is "unsafe" solely because the
2073 * caller must somehow ensure that the thread has not been
2074 * destroyed. Nothing special is usually required to ensure this
2075 * when called from Java (in which there will ordinarily be a live
2076 * reference to the thread) but this is not nearly-automatically
2077 * so when calling from native code.
2078 *
2079 * @param thread the thread to unpark.
2080 */
2081 @HotSpotIntrinsicCandidate
2082 public native void unpark(Object thread);
2083
2084 /**
2085 * Blocks current thread, returning when a balancing
2086 * {@code unpark} occurs, or a balancing {@code unpark} has
2087 * already occurred, or the thread is interrupted, or, if not
2088 * absolute and time is not zero, the given time nanoseconds have
2089 * elapsed, or if absolute, the given deadline in milliseconds
2090 * since Epoch has passed, or spuriously (i.e., returning for no
2091 * "reason"). Note: This operation is in the Unsafe class only
2092 * because {@code unpark} is, so it would be strange to place it
2093 * elsewhere.
2094 */
2095 @HotSpotIntrinsicCandidate
2096 public native void park(boolean isAbsolute, long time);
2097
2098 /**
2099 * Gets the load average in the system run queue assigned
2100 * to the available processors averaged over various periods of time.
2101 * This method retrieves the given {@code nelem} samples and
2102 * assigns to the elements of the given {@code loadavg} array.
2103 * The system imposes a maximum of 3 samples, representing
2104 * averages over the last 1, 5, and 15 minutes, respectively.
2105 *
2106 * @param loadavg an array of double of size nelems
2107 * @param nelems the number of samples to be retrieved and
2108 * must be 1 to 3.
2109 *
2110 * @return the number of samples actually retrieved; or -1
2111 * if the load average is unobtainable.
2112 */
2113 public int getLoadAverage(double[] loadavg, int nelems) {
2114 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2115 throw new ArrayIndexOutOfBoundsException();
2116 }
2117
2118 return getLoadAverage0(loadavg, nelems);
2119 }
2120
2121 // The following contain CAS-based Java implementations used on
2122 // platforms not supporting native instructions
2123
2124 /**
2125 * Atomically adds the given value to the current value of a field
2126 * or array element within the given object {@code o}
2127 * at the given {@code offset}.
2128 *
2129 * @param o object/array to update the field/element in
2130 * @param offset field/element offset
2131 * @param delta the value to add
2132 * @return the previous value
2133 * @since 1.8
2134 */
2135 @HotSpotIntrinsicCandidate
2136 public final int getAndAddInt(Object o, long offset, int delta) {
2137 int v;
2138 do {
2139 v = getIntVolatile(o, offset);
2140 } while (!weakCompareAndSwapIntVolatile(o, offset, v, v + delta));
2141 return v;
2142 }
2143
2144 /**
2145 * Atomically adds the given value to the current value of a field
2146 * or array element within the given object {@code o}
2147 * at the given {@code offset}.
2148 *
2149 * @param o object/array to update the field/element in
2150 * @param offset field/element offset
2151 * @param delta the value to add
2152 * @return the previous value
2153 * @since 1.8
2154 */
2155 @HotSpotIntrinsicCandidate
2156 public final long getAndAddLong(Object o, long offset, long delta) {
2157 long v;
2158 do {
2159 v = getLongVolatile(o, offset);
2160 } while (!weakCompareAndSwapLongVolatile(o, offset, v, v + delta));
2161 return v;
2162 }
2163
2164 @HotSpotIntrinsicCandidate
2165 public final byte getAndAddByte(Object o, long offset, byte delta) {
2166 byte v;
2167 do {
2168 v = getByteVolatile(o, offset);
2169 } while (!weakCompareAndSwapByteVolatile(o, offset, v, (byte) (v + delta)));
2170 return v;
2171 }
2172
2173 @HotSpotIntrinsicCandidate
2174 public final short getAndAddShort(Object o, long offset, short delta) {
2175 short v;
2176 do {
2177 v = getShortVolatile(o, offset);
2178 } while (!weakCompareAndSwapShortVolatile(o, offset, v, (short) (v + delta)));
2179 return v;
2180 }
2181
2182 public final char getAndAddChar(Object o, long offset, char delta) {
2183 return (char) getAndAddShort(o, offset, (short) delta);
2184 }
2185
2186 /**
2187 * Atomically exchanges the given value with the current value of
2188 * a field or array element within the given object {@code o}
2189 * at the given {@code offset}.
2190 *
2191 * @param o object/array to update the field/element in
2192 * @param offset field/element offset
2193 * @param newValue new value
2194 * @return the previous value
2195 * @since 1.8
2196 */
2197 @HotSpotIntrinsicCandidate
2198 public final int getAndSetInt(Object o, long offset, int newValue) {
2199 int v;
2200 do {
2201 v = getIntVolatile(o, offset);
2202 } while (!weakCompareAndSwapIntVolatile(o, offset, v, newValue));
2203 return v;
2204 }
2205
2206 /**
2207 * Atomically exchanges the given value with the current value of
2208 * a field or array element within the given object {@code o}
2209 * at the given {@code offset}.
2210 *
2211 * @param o object/array to update the field/element in
2212 * @param offset field/element offset
2213 * @param newValue new value
2214 * @return the previous value
2215 * @since 1.8
2216 */
2217 @HotSpotIntrinsicCandidate
2218 public final long getAndSetLong(Object o, long offset, long newValue) {
2219 long v;
2220 do {
2221 v = getLongVolatile(o, offset);
2222 } while (!weakCompareAndSwapLongVolatile(o, offset, v, newValue));
2223 return v;
2224 }
2225
2226 /**
2227 * Atomically exchanges the given reference value with the current
2228 * reference value of a field or array element within the given
2229 * object {@code o} at the given {@code offset}.
2230 *
2231 * @param o object/array to update the field/element in
2232 * @param offset field/element offset
2233 * @param newValue new value
2234 * @return the previous value
2235 * @since 1.8
2236 */
2237 @HotSpotIntrinsicCandidate
2238 public final Object getAndSetObject(Object o, long offset, Object newValue) {
2239 Object v;
2240 do {
2241 v = getObjectVolatile(o, offset);
2242 } while (!weakCompareAndSwapObjectVolatile(o, offset, v, newValue));
2243 return v;
2244 }
2245
2246 @HotSpotIntrinsicCandidate
2247 public final byte getAndSetByte(Object o, long offset, byte newValue) {
2248 byte v;
2249 do {
2250 v = getByteVolatile(o, offset);
2251 } while (!weakCompareAndSwapByteVolatile(o, offset, v, newValue));
2252 return v;
2253 }
2254
2255 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
2256 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
2257 }
2258
2259 @HotSpotIntrinsicCandidate
2260 public final short getAndSetShort(Object o, long offset, short newValue) {
2261 short v;
2262 do {
2263 v = getShortVolatile(o, offset);
2264 } while (!weakCompareAndSwapShortVolatile(o, offset, v, newValue));
2265 return v;
2266 }
2267
2268 public final char getAndSetChar(Object o, long offset, char newValue) {
2269 return s2c(getAndSetShort(o, offset, c2s(newValue)));
2270 }
2271
2272 /**
2273 * Ensures that loads before the fence will not be reordered with loads and
2274 * stores after the fence; a "LoadLoad plus LoadStore barrier".
2275 *
2276 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
2277 * (an "acquire fence").
2278 *
2279 * A pure LoadLoad fence is not provided, since the addition of LoadStore
2280 * is almost always desired, and most current hardware instructions that
2281 * provide a LoadLoad barrier also provide a LoadStore barrier for free.
2282 * @since 1.8
2283 */
2284 @HotSpotIntrinsicCandidate
2285 public native void loadFence();
2286
2287 /**
2288 * Ensures that loads and stores before the fence will not be reordered with
2289 * stores after the fence; a "StoreStore plus LoadStore barrier".
2290 *
2291 * Corresponds to C11 atomic_thread_fence(memory_order_release)
2292 * (a "release fence").
2293 *
2294 * A pure StoreStore fence is not provided, since the addition of LoadStore
2295 * is almost always desired, and most current hardware instructions that
2296 * provide a StoreStore barrier also provide a LoadStore barrier for free.
2297 * @since 1.8
2298 */
2299 @HotSpotIntrinsicCandidate
2300 public native void storeFence();
2301
2302 /**
2303 * Ensures that loads and stores before the fence will not be reordered
2304 * with loads and stores after the fence. Implies the effects of both
2305 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
2306 * barrier.
2307 *
2308 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
2309 * @since 1.8
2310 */
2311 @HotSpotIntrinsicCandidate
2312 public native void fullFence();
2313
2314 /**
2315 * Ensures that loads before the fence will not be reordered with
2316 * loads after the fence.
2317 */
2318 public final void loadLoadFence() {
2319 loadFence();
2320 }
2321
2322 /**
2323 * Ensures that stores before the fence will not be reordered with
2324 * stores after the fence.
2325 */
2326 public final void storeStoreFence() {
2327 storeFence();
2328 }
2329
2330
2331 /**
2332 * Throws IllegalAccessError; for use by the VM for access control
2333 * error support.
2334 * @since 1.8
2335 */
2336 private static void throwIllegalAccessError() {
2337 throw new IllegalAccessError();
2338 }
2339
2340 /**
2341 * @return Returns true if the native byte ordering of this
2342 * platform is big-endian, false if it is little-endian.
2343 */
2344 public final boolean isBigEndian() { return BE; }
2345
2346 /**
2347 * @return Returns true if this platform is capable of performing
2348 * accesses at addresses which are not aligned for the type of the
2349 * primitive type being accessed, false otherwise.
2350 */
2351 public final boolean unalignedAccess() { return unalignedAccess; }
2352
2353 /**
2354 * Fetches a value at some byte offset into a given Java object.
2355 * More specifically, fetches a value within the given object
2356 * <code>o</code> at the given offset, or (if <code>o</code> is
2357 * null) from the memory address whose numerical value is the
2358 * given offset. <p>
2359 *
2360 * The specification of this method is the same as {@link
2361 * #getLong(Object, long)} except that the offset does not need to
2362 * have been obtained from {@link #objectFieldOffset} on the
2363 * {@link java.lang.reflect.Field} of some Java field. The value
2364 * in memory is raw data, and need not correspond to any Java
2365 * variable. Unless <code>o</code> is null, the value accessed
2366 * must be entirely within the allocated object. The endianness
2367 * of the value in memory is the endianness of the native platform.
2368 *
2369 * <p> The read will be atomic with respect to the largest power
2370 * of two that divides the GCD of the offset and the storage size.
2371 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
2372 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
2373 * respectively. There are no other guarantees of atomicity.
2374 * <p>
2375 * 8-byte atomicity is only guaranteed on platforms on which
2376 * support atomic accesses to longs.
2377 *
2378 * @param o Java heap object in which the value resides, if any, else
2379 * null
2380 * @param offset The offset in bytes from the start of the object
2381 * @return the value fetched from the indicated object
2382 * @throws RuntimeException No defined exceptions are thrown, not even
2383 * {@link NullPointerException}
2384 * @since 9
2385 */
2386 @HotSpotIntrinsicCandidate
2387 public final long getLongUnaligned(Object o, long offset) {
2388 if ((offset & 7) == 0) {
2389 return getLong(o, offset);
2390 } else if ((offset & 3) == 0) {
2391 return makeLong(getInt(o, offset),
2392 getInt(o, offset + 4));
2393 } else if ((offset & 1) == 0) {
2394 return makeLong(getShort(o, offset),
2395 getShort(o, offset + 2),
2396 getShort(o, offset + 4),
2397 getShort(o, offset + 6));
2398 } else {
2399 return makeLong(getByte(o, offset),
2400 getByte(o, offset + 1),
2401 getByte(o, offset + 2),
2402 getByte(o, offset + 3),
2403 getByte(o, offset + 4),
2404 getByte(o, offset + 5),
2405 getByte(o, offset + 6),
2406 getByte(o, offset + 7));
2407 }
2408 }
2409 /**
2410 * As {@link #getLongUnaligned(Object, long)} but with an
2411 * additional argument which specifies the endianness of the value
2412 * as stored in memory.
2413 *
2414 * @param o Java heap object in which the variable resides
2415 * @param offset The offset in bytes from the start of the object
2416 * @param bigEndian The endianness of the value
2417 * @return the value fetched from the indicated object
2418 * @since 9
2419 */
2420 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
2421 return convEndian(bigEndian, getLongUnaligned(o, offset));
2422 }
2423
2424 /** @see #getLongUnaligned(Object, long) */
2425 @HotSpotIntrinsicCandidate
2426 public final int getIntUnaligned(Object o, long offset) {
2427 if ((offset & 3) == 0) {
2428 return getInt(o, offset);
2429 } else if ((offset & 1) == 0) {
2430 return makeInt(getShort(o, offset),
2431 getShort(o, offset + 2));
2432 } else {
2433 return makeInt(getByte(o, offset),
2434 getByte(o, offset + 1),
2435 getByte(o, offset + 2),
2436 getByte(o, offset + 3));
2437 }
2438 }
2439 /** @see #getLongUnaligned(Object, long, boolean) */
2440 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
2441 return convEndian(bigEndian, getIntUnaligned(o, offset));
2442 }
2443
2444 /** @see #getLongUnaligned(Object, long) */
2445 @HotSpotIntrinsicCandidate
2446 public final short getShortUnaligned(Object o, long offset) {
2447 if ((offset & 1) == 0) {
2448 return getShort(o, offset);
2449 } else {
2450 return makeShort(getByte(o, offset),
2451 getByte(o, offset + 1));
2452 }
2453 }
2454 /** @see #getLongUnaligned(Object, long, boolean) */
2455 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
2456 return convEndian(bigEndian, getShortUnaligned(o, offset));
2457 }
2458
2459 /** @see #getLongUnaligned(Object, long) */
2460 @HotSpotIntrinsicCandidate
2461 public final char getCharUnaligned(Object o, long offset) {
2462 if ((offset & 1) == 0) {
2463 return getChar(o, offset);
2464 } else {
2465 return (char)makeShort(getByte(o, offset),
2466 getByte(o, offset + 1));
2467 }
2468 }
2469
2470 /** @see #getLongUnaligned(Object, long, boolean) */
2471 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
2472 return convEndian(bigEndian, getCharUnaligned(o, offset));
2473 }
2474
2475 /**
2476 * Stores a value at some byte offset into a given Java object.
2477 * <p>
2478 * The specification of this method is the same as {@link
2479 * #getLong(Object, long)} except that the offset does not need to
2480 * have been obtained from {@link #objectFieldOffset} on the
2481 * {@link java.lang.reflect.Field} of some Java field. The value
2482 * in memory is raw data, and need not correspond to any Java
2483 * variable. The endianness of the value in memory is the
2484 * endianness of the native platform.
2485 * <p>
2486 * The write will be atomic with respect to the largest power of
2487 * two that divides the GCD of the offset and the storage size.
2488 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
2489 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
2490 * respectively. There are no other guarantees of atomicity.
2491 * <p>
2492 * 8-byte atomicity is only guaranteed on platforms on which
2493 * support atomic accesses to longs.
2494 *
2495 * @param o Java heap object in which the value resides, if any, else
2496 * null
2497 * @param offset The offset in bytes from the start of the object
2498 * @param x the value to store
2499 * @throws RuntimeException No defined exceptions are thrown, not even
2500 * {@link NullPointerException}
2501 * @since 9
2502 */
2503 @HotSpotIntrinsicCandidate
2504 public final void putLongUnaligned(Object o, long offset, long x) {
2505 if ((offset & 7) == 0) {
2506 putLong(o, offset, x);
2507 } else if ((offset & 3) == 0) {
2508 putLongParts(o, offset,
2509 (int)(x >> 0),
2510 (int)(x >>> 32));
2511 } else if ((offset & 1) == 0) {
2512 putLongParts(o, offset,
2513 (short)(x >>> 0),
2514 (short)(x >>> 16),
2515 (short)(x >>> 32),
2516 (short)(x >>> 48));
2517 } else {
2518 putLongParts(o, offset,
2519 (byte)(x >>> 0),
2520 (byte)(x >>> 8),
2521 (byte)(x >>> 16),
2522 (byte)(x >>> 24),
2523 (byte)(x >>> 32),
2524 (byte)(x >>> 40),
2525 (byte)(x >>> 48),
2526 (byte)(x >>> 56));
2527 }
2528 }
2529
2530 /**
2531 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
2532 * argument which specifies the endianness of the value as stored in memory.
2533 * @param o Java heap object in which the value resides
2534 * @param offset The offset in bytes from the start of the object
2535 * @param x the value to store
2536 * @param bigEndian The endianness of the value
2537 * @throws RuntimeException No defined exceptions are thrown, not even
2538 * {@link NullPointerException}
2539 * @since 9
2540 */
2541 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
2542 putLongUnaligned(o, offset, convEndian(bigEndian, x));
2543 }
2544
2545 /** @see #putLongUnaligned(Object, long, long) */
2546 @HotSpotIntrinsicCandidate
2547 public final void putIntUnaligned(Object o, long offset, int x) {
2548 if ((offset & 3) == 0) {
2549 putInt(o, offset, x);
2550 } else if ((offset & 1) == 0) {
2551 putIntParts(o, offset,
2552 (short)(x >> 0),
2553 (short)(x >>> 16));
2554 } else {
2555 putIntParts(o, offset,
2556 (byte)(x >>> 0),
2557 (byte)(x >>> 8),
2558 (byte)(x >>> 16),
2559 (byte)(x >>> 24));
2560 }
2561 }
2562 /** @see #putLongUnaligned(Object, long, long, boolean) */
2563 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
2564 putIntUnaligned(o, offset, convEndian(bigEndian, x));
2565 }
2566
2567 /** @see #putLongUnaligned(Object, long, long) */
2568 @HotSpotIntrinsicCandidate
2569 public final void putShortUnaligned(Object o, long offset, short x) {
2570 if ((offset & 1) == 0) {
2571 putShort(o, offset, x);
2572 } else {
2573 putShortParts(o, offset,
2574 (byte)(x >>> 0),
2575 (byte)(x >>> 8));
2576 }
2577 }
2578 /** @see #putLongUnaligned(Object, long, long, boolean) */
2579 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
2580 putShortUnaligned(o, offset, convEndian(bigEndian, x));
2581 }
2582
2583 /** @see #putLongUnaligned(Object, long, long) */
2584 @HotSpotIntrinsicCandidate
2585 public final void putCharUnaligned(Object o, long offset, char x) {
2586 putShortUnaligned(o, offset, (short)x);
2587 }
2588 /** @see #putLongUnaligned(Object, long, long, boolean) */
2589 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
2590 putCharUnaligned(o, offset, convEndian(bigEndian, x));
2591 }
2592
2593 // JVM interface methods
2594 // BE is true iff the native endianness of this platform is big.
2595 private static final boolean BE = theUnsafe.isBigEndian0();
2596
2597 // unalignedAccess is true iff this platform can perform unaligned accesses.
2598 private static final boolean unalignedAccess = theUnsafe.unalignedAccess0();
2599
2600 private static int pickPos(int top, int pos) { return BE ? top - pos : pos; }
2601
2602 // These methods construct integers from bytes. The byte ordering
2603 // is the native endianness of this platform.
2604 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
2605 return ((toUnsignedLong(i0) << pickPos(56, 0))
2606 | (toUnsignedLong(i1) << pickPos(56, 8))
2607 | (toUnsignedLong(i2) << pickPos(56, 16))
2608 | (toUnsignedLong(i3) << pickPos(56, 24))
2609 | (toUnsignedLong(i4) << pickPos(56, 32))
2610 | (toUnsignedLong(i5) << pickPos(56, 40))
2611 | (toUnsignedLong(i6) << pickPos(56, 48))
2612 | (toUnsignedLong(i7) << pickPos(56, 56)));
2613 }
2614 private static long makeLong(short i0, short i1, short i2, short i3) {
2615 return ((toUnsignedLong(i0) << pickPos(48, 0))
2616 | (toUnsignedLong(i1) << pickPos(48, 16))
2617 | (toUnsignedLong(i2) << pickPos(48, 32))
2618 | (toUnsignedLong(i3) << pickPos(48, 48)));
2619 }
2620 private static long makeLong(int i0, int i1) {
2621 return (toUnsignedLong(i0) << pickPos(32, 0))
2622 | (toUnsignedLong(i1) << pickPos(32, 32));
2623 }
2624 private static int makeInt(short i0, short i1) {
2625 return (toUnsignedInt(i0) << pickPos(16, 0))
2626 | (toUnsignedInt(i1) << pickPos(16, 16));
2627 }
2628 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
2629 return ((toUnsignedInt(i0) << pickPos(24, 0))
2630 | (toUnsignedInt(i1) << pickPos(24, 8))
2631 | (toUnsignedInt(i2) << pickPos(24, 16))
2632 | (toUnsignedInt(i3) << pickPos(24, 24)));
2633 }
2634 private static short makeShort(byte i0, byte i1) {
2635 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
2636 | (toUnsignedInt(i1) << pickPos(8, 8)));
2637 }
2638
2639 private static byte pick(byte le, byte be) { return BE ? be : le; }
2640 private static short pick(short le, short be) { return BE ? be : le; }
2641 private static int pick(int le, int be) { return BE ? be : le; }
2642
2643 // These methods write integers to memory from smaller parts
2644 // provided by their caller. The ordering in which these parts
2645 // are written is the native endianness of this platform.
2646 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
2647 putByte(o, offset + 0, pick(i0, i7));
2648 putByte(o, offset + 1, pick(i1, i6));
2649 putByte(o, offset + 2, pick(i2, i5));
2650 putByte(o, offset + 3, pick(i3, i4));
2651 putByte(o, offset + 4, pick(i4, i3));
2652 putByte(o, offset + 5, pick(i5, i2));
2653 putByte(o, offset + 6, pick(i6, i1));
2654 putByte(o, offset + 7, pick(i7, i0));
2655 }
2656 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
2657 putShort(o, offset + 0, pick(i0, i3));
2658 putShort(o, offset + 2, pick(i1, i2));
2659 putShort(o, offset + 4, pick(i2, i1));
2660 putShort(o, offset + 6, pick(i3, i0));
2661 }
2662 private void putLongParts(Object o, long offset, int i0, int i1) {
2663 putInt(o, offset + 0, pick(i0, i1));
2664 putInt(o, offset + 4, pick(i1, i0));
2665 }
2666 private void putIntParts(Object o, long offset, short i0, short i1) {
2667 putShort(o, offset + 0, pick(i0, i1));
2668 putShort(o, offset + 2, pick(i1, i0));
2669 }
2670 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
2671 putByte(o, offset + 0, pick(i0, i3));
2672 putByte(o, offset + 1, pick(i1, i2));
2673 putByte(o, offset + 2, pick(i2, i1));
2674 putByte(o, offset + 3, pick(i3, i0));
2675 }
2676 private void putShortParts(Object o, long offset, byte i0, byte i1) {
2677 putByte(o, offset + 0, pick(i0, i1));
2678 putByte(o, offset + 1, pick(i1, i0));
2679 }
2680
2681 // Zero-extend an integer
2682 private static int toUnsignedInt(byte n) { return n & 0xff; }
2683 private static int toUnsignedInt(short n) { return n & 0xffff; }
2684 private static long toUnsignedLong(byte n) { return n & 0xffl; }
2685 private static long toUnsignedLong(short n) { return n & 0xffffl; }
2686 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
2687
2688 // Maybe byte-reverse an integer
2689 private static char convEndian(boolean big, char n) { return big == BE ? n : Character.reverseBytes(n); }
2690 private static short convEndian(boolean big, short n) { return big == BE ? n : Short.reverseBytes(n) ; }
2691 private static int convEndian(boolean big, int n) { return big == BE ? n : Integer.reverseBytes(n) ; }
2692 private static long convEndian(boolean big, long n) { return big == BE ? n : Long.reverseBytes(n) ; }
2693
2694
2695
2696 private native long allocateMemory0(long bytes);
2697 private native long reallocateMemory0(long address, long bytes);
2698 private native void freeMemory0(long address);
2699 private native void setMemory0(Object o, long offset, long bytes, byte value);
2700 @HotSpotIntrinsicCandidate
2701 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
2702 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
2703 private native long objectFieldOffset0(Field f);
2704 private native long staticFieldOffset0(Field f);
2705 private native Object staticFieldBase0(Field f);
2706 private native boolean shouldBeInitialized0(Class<?> c);
2707 private native void ensureClassInitialized0(Class<?> c);
2708 private native int arrayBaseOffset0(Class<?> arrayClass);
2709 private native int arrayIndexScale0(Class<?> arrayClass);
2710 private native int addressSize0();
2711 private native Class<?> defineAnonymousClass0(Class<?> hostClass, byte[] data, Object[] cpPatches);
2712 private native int getLoadAverage0(double[] loadavg, int nelems);
2713 private native boolean unalignedAccess0();
2714 private native boolean isBigEndian0();
2715 }