-
Notifications
You must be signed in to change notification settings - Fork 5.5k
/
Unsafe.java
3865 lines (3421 loc) · 145 KB
/
Unsafe.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Copyright (c) 2000, 2024, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.internal.misc;
import jdk.internal.ref.Cleaner;
import jdk.internal.vm.annotation.ForceInline;
import jdk.internal.vm.annotation.IntrinsicCandidate;
import sun.nio.ch.DirectBuffer;
import java.lang.reflect.Field;
import java.security.ProtectionDomain;
import static jdk.internal.misc.UnsafeConstants.*;
/**
* A collection of methods for performing low-level, unsafe operations.
* Although the class and all methods are public, use of this class is
* limited because only trusted code can obtain instances of it.
*
* <em>Note:</em> It is the responsibility of the caller to make sure
* arguments are checked before methods of this class are
* called. While some rudimentary checks are performed on the input,
* the checks are best effort and when performance is an overriding
* priority, as when methods of this class are optimized by the
* runtime compiler, some or all checks (if any) may be elided. Hence,
* the caller must not rely on the checks and corresponding
* exceptions!
*
* @author John R. Rose
* @see #getUnsafe
*/
public final class Unsafe {
private static native void registerNatives();
static {
registerNatives();
}
private Unsafe() {}
private static final Unsafe theUnsafe = new Unsafe();
/**
* Provides the caller with the capability of performing unsafe
* operations.
*
* <p>The returned {@code Unsafe} object should be carefully guarded
* by the caller, since it can be used to read and write data at arbitrary
* memory addresses. It must never be passed to untrusted code.
*
* <p>Most methods in this class are very low-level, and correspond to a
* small number of hardware instructions (on typical machines). Compilers
* are encouraged to optimize these methods accordingly.
*
* <p>Here is a suggested idiom for using unsafe operations:
*
* <pre> {@code
* class MyTrustedClass {
* private static final Unsafe unsafe = Unsafe.getUnsafe();
* ...
* private long myCountAddress = ...;
* public int getCount() { return unsafe.getByte(myCountAddress); }
* }}</pre>
*
* (It may assist compilers to make the local variable {@code final}.)
*/
public static Unsafe getUnsafe() {
return theUnsafe;
}
/// peek and poke operations
/// (compilers should optimize these to memory ops)
// These work on object fields in the Java heap.
// They will not work on elements of packed arrays.
/**
* Fetches a value from a given Java variable.
* More specifically, fetches a field or array element within the given
* object {@code o} at the given offset, or (if {@code o} is null)
* from the memory address whose numerical value is the given offset.
* <p>
* The results are undefined unless one of the following cases is true:
* <ul>
* <li>The offset was obtained from {@link #objectFieldOffset} on
* the {@link java.lang.reflect.Field} of some Java field and the object
* referred to by {@code o} is of a class compatible with that
* field's class.
*
* <li>The offset and object reference {@code o} (either null or
* non-null) were both obtained via {@link #staticFieldOffset}
* and {@link #staticFieldBase} (respectively) from the
* reflective {@link Field} representation of some Java field.
*
* <li>The object referred to by {@code o} is an array, and the offset
* is an integer of the form {@code B+N*S}, where {@code N} is
* a valid index into the array, and {@code B} and {@code S} are
* the values obtained by {@link #arrayBaseOffset} and {@link
* #arrayIndexScale} (respectively) from the array's class. The value
* referred to is the {@code N}<em>th</em> element of the array.
*
* </ul>
* <p>
* If one of the above cases is true, the call references a specific Java
* variable (field or array element). However, the results are undefined
* if that variable is not in fact of the type returned by this method.
* <p>
* This method refers to a variable by means of two parameters, and so
* it provides (in effect) a <em>double-register</em> addressing mode
* for Java variables. When the object reference is null, this method
* uses its offset as an absolute address. This is similar in operation
* to methods such as {@link #getInt(long)}, which provide (in effect) a
* <em>single-register</em> addressing mode for non-Java variables.
* However, because Java variables may have a different layout in memory
* from non-Java variables, programmers should not assume that these
* two addressing modes are ever equivalent. Also, programmers should
* remember that offsets from the double-register addressing mode cannot
* be portably confused with longs used in the single-register addressing
* mode.
*
* @param o Java heap object in which the variable resides, if any, else
* null
* @param offset indication of where the variable resides in a Java heap
* object, if any, else a memory address locating the variable
* statically
* @return the value fetched from the indicated Java variable
* @throws RuntimeException No defined exceptions are thrown, not even
* {@link NullPointerException}
*/
@IntrinsicCandidate
public native int getInt(Object o, long offset);
/**
* Stores a value into a given Java variable.
* <p>
* The first two parameters are interpreted exactly as with
* {@link #getInt(Object, long)} to refer to a specific
* Java variable (field or array element). The given value
* is stored into that variable.
* <p>
* The variable must be of the same type as the method
* parameter {@code x}.
*
* @param o Java heap object in which the variable resides, if any, else
* null
* @param offset indication of where the variable resides in a Java heap
* object, if any, else a memory address locating the variable
* statically
* @param x the value to store into the indicated Java variable
* @throws RuntimeException No defined exceptions are thrown, not even
* {@link NullPointerException}
*/
@IntrinsicCandidate
public native void putInt(Object o, long offset, int x);
/**
* Fetches a reference value from a given Java variable.
* @see #getInt(Object, long)
*/
@IntrinsicCandidate
public native Object getReference(Object o, long offset);
/**
* Stores a reference value into a given Java variable.
* <p>
* Unless the reference {@code x} being stored is either null
* or matches the field type, the results are undefined.
* If the reference {@code o} is non-null, card marks or
* other store barriers for that object (if the VM requires them)
* are updated.
* @see #putInt(Object, long, int)
*/
@IntrinsicCandidate
public native void putReference(Object o, long offset, Object x);
/** @see #getInt(Object, long) */
@IntrinsicCandidate
public native boolean getBoolean(Object o, long offset);
/** @see #putInt(Object, long, int) */
@IntrinsicCandidate
public native void putBoolean(Object o, long offset, boolean x);
/** @see #getInt(Object, long) */
@IntrinsicCandidate
public native byte getByte(Object o, long offset);
/** @see #putInt(Object, long, int) */
@IntrinsicCandidate
public native void putByte(Object o, long offset, byte x);
/** @see #getInt(Object, long) */
@IntrinsicCandidate
public native short getShort(Object o, long offset);
/** @see #putInt(Object, long, int) */
@IntrinsicCandidate
public native void putShort(Object o, long offset, short x);
/** @see #getInt(Object, long) */
@IntrinsicCandidate
public native char getChar(Object o, long offset);
/** @see #putInt(Object, long, int) */
@IntrinsicCandidate
public native void putChar(Object o, long offset, char x);
/** @see #getInt(Object, long) */
@IntrinsicCandidate
public native long getLong(Object o, long offset);
/** @see #putInt(Object, long, int) */
@IntrinsicCandidate
public native void putLong(Object o, long offset, long x);
/** @see #getInt(Object, long) */
@IntrinsicCandidate
public native float getFloat(Object o, long offset);
/** @see #putInt(Object, long, int) */
@IntrinsicCandidate
public native void putFloat(Object o, long offset, float x);
/** @see #getInt(Object, long) */
@IntrinsicCandidate
public native double getDouble(Object o, long offset);
/** @see #putInt(Object, long, int) */
@IntrinsicCandidate
public native void putDouble(Object o, long offset, double x);
/**
* Fetches a native pointer from a given memory address. If the address is
* zero, or does not point into a block obtained from {@link
* #allocateMemory}, the results are undefined.
*
* <p>If the native pointer is less than 64 bits wide, it is extended as
* an unsigned number to a Java long. The pointer may be indexed by any
* given byte offset, simply by adding that offset (as a simple integer) to
* the long representing the pointer. The number of bytes actually read
* from the target address may be determined by consulting {@link
* #addressSize}.
*
* @see #allocateMemory
* @see #getInt(Object, long)
*/
@ForceInline
public long getAddress(Object o, long offset) {
if (ADDRESS_SIZE == 4) {
return Integer.toUnsignedLong(getInt(o, offset));
} else {
return getLong(o, offset);
}
}
/**
* Stores a native pointer into a given memory address. If the address is
* zero, or does not point into a block obtained from {@link
* #allocateMemory}, the results are undefined.
*
* <p>The number of bytes actually written at the target address may be
* determined by consulting {@link #addressSize}.
*
* @see #allocateMemory
* @see #putInt(Object, long, int)
*/
@ForceInline
public void putAddress(Object o, long offset, long x) {
if (ADDRESS_SIZE == 4) {
putInt(o, offset, (int)x);
} else {
putLong(o, offset, x);
}
}
// These read VM internal data.
/**
* Fetches an uncompressed reference value from a given native variable
* ignoring the VM's compressed references mode.
*
* @param address a memory address locating the variable
* @return the value fetched from the indicated native variable
*/
public native Object getUncompressedObject(long address);
// These work on values in the C heap.
/**
* Fetches a value from a given memory address. If the address is zero, or
* does not point into a block obtained from {@link #allocateMemory}, the
* results are undefined.
*
* @see #allocateMemory
*/
@ForceInline
public byte getByte(long address) {
return getByte(null, address);
}
/**
* Stores a value into a given memory address. If the address is zero, or
* does not point into a block obtained from {@link #allocateMemory}, the
* results are undefined.
*
* @see #getByte(long)
*/
@ForceInline
public void putByte(long address, byte x) {
putByte(null, address, x);
}
/** @see #getByte(long) */
@ForceInline
public short getShort(long address) {
return getShort(null, address);
}
/** @see #putByte(long, byte) */
@ForceInline
public void putShort(long address, short x) {
putShort(null, address, x);
}
/** @see #getByte(long) */
@ForceInline
public char getChar(long address) {
return getChar(null, address);
}
/** @see #putByte(long, byte) */
@ForceInline
public void putChar(long address, char x) {
putChar(null, address, x);
}
/** @see #getByte(long) */
@ForceInline
public int getInt(long address) {
return getInt(null, address);
}
/** @see #putByte(long, byte) */
@ForceInline
public void putInt(long address, int x) {
putInt(null, address, x);
}
/** @see #getByte(long) */
@ForceInline
public long getLong(long address) {
return getLong(null, address);
}
/** @see #putByte(long, byte) */
@ForceInline
public void putLong(long address, long x) {
putLong(null, address, x);
}
/** @see #getByte(long) */
@ForceInline
public float getFloat(long address) {
return getFloat(null, address);
}
/** @see #putByte(long, byte) */
@ForceInline
public void putFloat(long address, float x) {
putFloat(null, address, x);
}
/** @see #getByte(long) */
@ForceInline
public double getDouble(long address) {
return getDouble(null, address);
}
/** @see #putByte(long, byte) */
@ForceInline
public void putDouble(long address, double x) {
putDouble(null, address, x);
}
/** @see #getAddress(Object, long) */
@ForceInline
public long getAddress(long address) {
return getAddress(null, address);
}
/** @see #putAddress(Object, long, long) */
@ForceInline
public void putAddress(long address, long x) {
putAddress(null, address, x);
}
/// helper methods for validating various types of objects/values
/**
* Create an exception reflecting that some of the input was invalid
*
* <em>Note:</em> It is the responsibility of the caller to make
* sure arguments are checked before the methods are called. While
* some rudimentary checks are performed on the input, the checks
* are best effort and when performance is an overriding priority,
* as when methods of this class are optimized by the runtime
* compiler, some or all checks (if any) may be elided. Hence, the
* caller must not rely on the checks and corresponding
* exceptions!
*
* @return an exception object
*/
private RuntimeException invalidInput() {
return new IllegalArgumentException();
}
/**
* Check if a value is 32-bit clean (32 MSB are all zero)
*
* @param value the 64-bit value to check
*
* @return true if the value is 32-bit clean
*/
private boolean is32BitClean(long value) {
return value >>> 32 == 0;
}
/**
* Check the validity of a size (the equivalent of a size_t)
*
* @throws RuntimeException if the size is invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void checkSize(long size) {
if (ADDRESS_SIZE == 4) {
// Note: this will also check for negative sizes
if (!is32BitClean(size)) {
throw invalidInput();
}
} else if (size < 0) {
throw invalidInput();
}
}
/**
* Check the validity of a native address (the equivalent of void*)
*
* @throws RuntimeException if the address is invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void checkNativeAddress(long address) {
if (ADDRESS_SIZE == 4) {
// Accept both zero and sign extended pointers. A valid
// pointer will, after the +1 below, either have produced
// the value 0x0 or 0x1. Masking off the low bit allows
// for testing against 0.
if ((((address >> 32) + 1) & ~1) != 0) {
throw invalidInput();
}
}
}
/**
* Check the validity of an offset, relative to a base object
*
* @param o the base object
* @param offset the offset to check
*
* @throws RuntimeException if the size is invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void checkOffset(Object o, long offset) {
if (ADDRESS_SIZE == 4) {
// Note: this will also check for negative offsets
if (!is32BitClean(offset)) {
throw invalidInput();
}
} else if (offset < 0) {
throw invalidInput();
}
}
/**
* Check the validity of a double-register pointer
*
* Note: This code deliberately does *not* check for NPE for (at
* least) three reasons:
*
* 1) NPE is not just NULL/0 - there is a range of values all
* resulting in an NPE, which is not trivial to check for
*
* 2) It is the responsibility of the callers of Unsafe methods
* to verify the input, so throwing an exception here is not really
* useful - passing in a NULL pointer is a critical error and the
* must not expect an exception to be thrown anyway.
*
* 3) the actual operations will detect NULL pointers anyway by
* means of traps and signals (like SIGSEGV).
*
* @param o Java heap object, or null
* @param offset indication of where the variable resides in a Java heap
* object, if any, else a memory address locating the variable
* statically
*
* @throws RuntimeException if the pointer is invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void checkPointer(Object o, long offset) {
if (o == null) {
checkNativeAddress(offset);
} else {
checkOffset(o, offset);
}
}
/**
* Check if a type is a primitive array type
*
* @param c the type to check
*
* @return true if the type is a primitive array type
*/
private void checkPrimitiveArray(Class<?> c) {
Class<?> componentType = c.getComponentType();
if (componentType == null || !componentType.isPrimitive()) {
throw invalidInput();
}
}
/**
* Check that a pointer is a valid primitive array type pointer
*
* Note: pointers off-heap are considered to be primitive arrays
*
* @throws RuntimeException if the pointer is invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void checkPrimitivePointer(Object o, long offset) {
checkPointer(o, offset);
if (o != null) {
// If on heap, it must be a primitive array
checkPrimitiveArray(o.getClass());
}
}
/// wrappers for malloc, realloc, free:
/**
* Round up allocation size to a multiple of HeapWordSize.
*/
private long alignToHeapWordSize(long bytes) {
if (bytes >= 0) {
return (bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1);
} else {
throw invalidInput();
}
}
/**
* Allocates a new block of native memory, of the given size in bytes. The
* contents of the memory are uninitialized; they will generally be
* garbage. The resulting native pointer will be zero if and only if the
* requested size is zero. The resulting native pointer will be aligned for
* all value types. Dispose of this memory by calling {@link #freeMemory}
* or resize it with {@link #reallocateMemory}.
*
* <em>Note:</em> It is the responsibility of the caller to make
* sure arguments are checked before the methods are called. While
* some rudimentary checks are performed on the input, the checks
* are best effort and when performance is an overriding priority,
* as when methods of this class are optimized by the runtime
* compiler, some or all checks (if any) may be elided. Hence, the
* caller must not rely on the checks and corresponding
* exceptions!
*
* @throws RuntimeException if the size is negative or too large
* for the native size_t type
*
* @throws OutOfMemoryError if the allocation is refused by the system
*
* @see #getByte(long)
* @see #putByte(long, byte)
*/
public long allocateMemory(long bytes) {
bytes = alignToHeapWordSize(bytes);
allocateMemoryChecks(bytes);
if (bytes == 0) {
return 0;
}
long p = allocateMemory0(bytes);
if (p == 0) {
throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
}
return p;
}
/**
* Validate the arguments to allocateMemory
*
* @throws RuntimeException if the arguments are invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void allocateMemoryChecks(long bytes) {
checkSize(bytes);
}
/**
* Resizes a new block of native memory, to the given size in bytes. The
* contents of the new block past the size of the old block are
* uninitialized; they will generally be garbage. The resulting native
* pointer will be zero if and only if the requested size is zero. The
* resulting native pointer will be aligned for all value types. Dispose
* of this memory by calling {@link #freeMemory}, or resize it with {@link
* #reallocateMemory}. The address passed to this method may be null, in
* which case an allocation will be performed.
*
* <em>Note:</em> It is the responsibility of the caller to make
* sure arguments are checked before the methods are called. While
* some rudimentary checks are performed on the input, the checks
* are best effort and when performance is an overriding priority,
* as when methods of this class are optimized by the runtime
* compiler, some or all checks (if any) may be elided. Hence, the
* caller must not rely on the checks and corresponding
* exceptions!
*
* @throws RuntimeException if the size is negative or too large
* for the native size_t type
*
* @throws OutOfMemoryError if the allocation is refused by the system
*
* @see #allocateMemory
*/
public long reallocateMemory(long address, long bytes) {
bytes = alignToHeapWordSize(bytes);
reallocateMemoryChecks(address, bytes);
if (bytes == 0) {
freeMemory(address);
return 0;
}
long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
if (p == 0) {
throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
}
return p;
}
/**
* Validate the arguments to reallocateMemory
*
* @throws RuntimeException if the arguments are invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void reallocateMemoryChecks(long address, long bytes) {
checkPointer(null, address);
checkSize(bytes);
}
/**
* Sets all bytes in a given block of memory to a fixed value
* (usually zero).
*
* <p>This method determines a block's base address by means of two parameters,
* and so it provides (in effect) a <em>double-register</em> addressing mode,
* as discussed in {@link #getInt(Object,long)}. When the object reference is null,
* the offset supplies an absolute base address.
*
* <p>The stores are in coherent (atomic) units of a size determined
* by the address and length parameters. If the effective address and
* length are all even modulo 8, the stores take place in 'long' units.
* If the effective address and length are (resp.) even modulo 4 or 2,
* the stores take place in units of 'int' or 'short'.
*
* <em>Note:</em> It is the responsibility of the caller to make
* sure arguments are checked before the methods are called. While
* some rudimentary checks are performed on the input, the checks
* are best effort and when performance is an overriding priority,
* as when methods of this class are optimized by the runtime
* compiler, some or all checks (if any) may be elided. Hence, the
* caller must not rely on the checks and corresponding
* exceptions!
*
* @throws RuntimeException if any of the arguments is invalid
*
* @since 1.7
*/
public void setMemory(Object o, long offset, long bytes, byte value) {
setMemoryChecks(o, offset, bytes, value);
if (bytes == 0) {
return;
}
setMemory0(o, offset, bytes, value);
}
/**
* Sets all bytes in a given block of memory to a fixed value
* (usually zero). This provides a <em>single-register</em> addressing mode,
* as discussed in {@link #getInt(Object,long)}.
*
* <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
*/
public void setMemory(long address, long bytes, byte value) {
setMemory(null, address, bytes, value);
}
/**
* Validate the arguments to setMemory
*
* @throws RuntimeException if the arguments are invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
checkPrimitivePointer(o, offset);
checkSize(bytes);
}
/**
* Sets all bytes in a given block of memory to a copy of another
* block.
*
* <p>This method determines each block's base address by means of two parameters,
* and so it provides (in effect) a <em>double-register</em> addressing mode,
* as discussed in {@link #getInt(Object,long)}. When the object reference is null,
* the offset supplies an absolute base address.
*
* <p>The transfers are in coherent (atomic) units of a size determined
* by the address and length parameters. If the effective addresses and
* length are all even modulo 8, the transfer takes place in 'long' units.
* If the effective addresses and length are (resp.) even modulo 4 or 2,
* the transfer takes place in units of 'int' or 'short'.
*
* <em>Note:</em> It is the responsibility of the caller to make
* sure arguments are checked before the methods are called. While
* some rudimentary checks are performed on the input, the checks
* are best effort and when performance is an overriding priority,
* as when methods of this class are optimized by the runtime
* compiler, some or all checks (if any) may be elided. Hence, the
* caller must not rely on the checks and corresponding
* exceptions!
*
* @throws RuntimeException if any of the arguments is invalid
*
* @since 1.7
*/
public void copyMemory(Object srcBase, long srcOffset,
Object destBase, long destOffset,
long bytes) {
copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
if (bytes == 0) {
return;
}
copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
}
/**
* Sets all bytes in a given block of memory to a copy of another
* block. This provides a <em>single-register</em> addressing mode,
* as discussed in {@link #getInt(Object,long)}.
*
* Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
*/
public void copyMemory(long srcAddress, long destAddress, long bytes) {
copyMemory(null, srcAddress, null, destAddress, bytes);
}
/**
* Validate the arguments to copyMemory
*
* @throws RuntimeException if any of the arguments is invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void copyMemoryChecks(Object srcBase, long srcOffset,
Object destBase, long destOffset,
long bytes) {
checkSize(bytes);
checkPrimitivePointer(srcBase, srcOffset);
checkPrimitivePointer(destBase, destOffset);
}
/**
* Copies all elements from one block of memory to another block,
* *unconditionally* byte swapping the elements on the fly.
*
* <p>This method determines each block's base address by means of two parameters,
* and so it provides (in effect) a <em>double-register</em> addressing mode,
* as discussed in {@link #getInt(Object,long)}. When the object reference is null,
* the offset supplies an absolute base address.
*
* <em>Note:</em> It is the responsibility of the caller to make
* sure arguments are checked before the methods are called. While
* some rudimentary checks are performed on the input, the checks
* are best effort and when performance is an overriding priority,
* as when methods of this class are optimized by the runtime
* compiler, some or all checks (if any) may be elided. Hence, the
* caller must not rely on the checks and corresponding
* exceptions!
*
* @throws RuntimeException if any of the arguments is invalid
*
* @since 9
*/
public void copySwapMemory(Object srcBase, long srcOffset,
Object destBase, long destOffset,
long bytes, long elemSize) {
copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
if (bytes == 0) {
return;
}
copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
}
private void copySwapMemoryChecks(Object srcBase, long srcOffset,
Object destBase, long destOffset,
long bytes, long elemSize) {
checkSize(bytes);
if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
throw invalidInput();
}
if (bytes % elemSize != 0) {
throw invalidInput();
}
checkPrimitivePointer(srcBase, srcOffset);
checkPrimitivePointer(destBase, destOffset);
}
/**
* Copies all elements from one block of memory to another block, byte swapping the
* elements on the fly.
*
* This provides a <em>single-register</em> addressing mode, as
* discussed in {@link #getInt(Object,long)}.
*
* Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
*/
public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
}
/**
* Disposes of a block of native memory, as obtained from {@link
* #allocateMemory} or {@link #reallocateMemory}. The address passed to
* this method may be null, in which case no action is taken.
*
* <em>Note:</em> It is the responsibility of the caller to make
* sure arguments are checked before the methods are called. While
* some rudimentary checks are performed on the input, the checks
* are best effort and when performance is an overriding priority,
* as when methods of this class are optimized by the runtime
* compiler, some or all checks (if any) may be elided. Hence, the
* caller must not rely on the checks and corresponding
* exceptions!
*
* @throws RuntimeException if any of the arguments is invalid
*
* @see #allocateMemory
*/
public void freeMemory(long address) {
freeMemoryChecks(address);
if (address == 0) {
return;
}
freeMemory0(address);
}
/**
* Validate the arguments to freeMemory
*
* @throws RuntimeException if the arguments are invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void freeMemoryChecks(long address) {
checkPointer(null, address);
}
/**
* Ensure writeback of a specified virtual memory address range
* from cache to physical memory. All bytes in the address range
* are guaranteed to have been written back to physical memory on
* return from this call i.e. subsequently executed store
* instructions are guaranteed not to be visible before the
* writeback is completed.
*
* @param address
* the lowest byte address that must be guaranteed written
* back to memory. bytes at lower addresses may also be
* written back.
*
* @param length
* the length in bytes of the region starting at address
* that must be guaranteed written back to memory.
*
* @throws RuntimeException if memory writeback is not supported
* on the current hardware of if the arguments are invalid.
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*
* @since 14
*/
public void writebackMemory(long address, long length) {
checkWritebackEnabled();
checkWritebackMemory(address, length);
// perform any required pre-writeback barrier
writebackPreSync0();
// write back one cache line at a time
long line = dataCacheLineAlignDown(address);
long end = address + length;
while (line < end) {
writeback0(line);
line += dataCacheLineFlushSize();
}
// perform any required post-writeback barrier
writebackPostSync0();
}
/**
* Validate the arguments to writebackMemory
*
* @throws RuntimeException if the arguments are invalid
* (<em>Note:</em> after optimization, invalid inputs may
* go undetected, which will lead to unpredictable
* behavior)
*/
private void checkWritebackMemory(long address, long length) {
checkNativeAddress(address);
checkSize(length);
}
/**
* Validate that the current hardware supports memory writeback.
* (<em>Note:</em> this is a belt and braces check. Clients are