1/* 2 * Copyright (c) 2000, 2017, 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 26package jdk.internal.misc; 27 28import jdk.internal.HotSpotIntrinsicCandidate; 29import jdk.internal.vm.annotation.ForceInline; 30 31import java.lang.reflect.Field; 32import java.security.ProtectionDomain; 33 34 35/** 36 * A collection of methods for performing low-level, unsafe operations. 37 * Although the class and all methods are public, use of this class is 38 * limited because only trusted code can obtain instances of it. 39 * 40 * <em>Note:</em> It is the resposibility of the caller to make sure 41 * arguments are checked before methods of this class are 42 * called. While some rudimentary checks are performed on the input, 43 * the checks are best effort and when performance is an overriding 44 * priority, as when methods of this class are optimized by the 45 * runtime compiler, some or all checks (if any) may be elided. Hence, 46 * the caller must not rely on the checks and corresponding 47 * exceptions! 48 * 49 * @author John R. Rose 50 * @see #getUnsafe 51 */ 52 53public final class Unsafe { 54 55 private static native void registerNatives(); 56 static { 57 registerNatives(); 58 } 59 60 private Unsafe() {} 61 62 private static final Unsafe theUnsafe = new Unsafe(); 63 64 /** 65 * Provides the caller with the capability of performing unsafe 66 * operations. 67 * 68 * <p>The returned {@code Unsafe} object should be carefully guarded 69 * by the caller, since it can be used to read and write data at arbitrary 70 * memory addresses. It must never be passed to untrusted code. 71 * 72 * <p>Most methods in this class are very low-level, and correspond to a 73 * small number of hardware instructions (on typical machines). Compilers 74 * are encouraged to optimize these methods accordingly. 75 * 76 * <p>Here is a suggested idiom for using unsafe operations: 77 * 78 * <pre> {@code 79 * class MyTrustedClass { 80 * private static final Unsafe unsafe = Unsafe.getUnsafe(); 81 * ... 82 * private long myCountAddress = ...; 83 * public int getCount() { return unsafe.getByte(myCountAddress); } 84 * }}</pre> 85 * 86 * (It may assist compilers to make the local variable {@code final}.) 87 */ 88 public static Unsafe getUnsafe() { 89 return theUnsafe; 90 } 91 92 /// peek and poke operations 93 /// (compilers should optimize these to memory ops) 94 95 // These work on object fields in the Java heap. 96 // They will not work on elements of packed arrays. 97 98 /** 99 * Fetches a value from a given Java variable. 100 * More specifically, fetches a field or array element within the given 101 * object {@code o} at the given offset, or (if {@code o} is null) 102 * from the memory address whose numerical value is the given offset. 103 * <p> 104 * The results are undefined unless one of the following cases is true: 105 * <ul> 106 * <li>The offset was obtained from {@link #objectFieldOffset} on 107 * the {@link java.lang.reflect.Field} of some Java field and the object 108 * referred to by {@code o} is of a class compatible with that 109 * field's class. 110 * 111 * <li>The offset and object reference {@code o} (either null or 112 * non-null) were both obtained via {@link #staticFieldOffset} 113 * and {@link #staticFieldBase} (respectively) from the 114 * reflective {@link Field} representation of some Java field. 115 * 116 * <li>The object referred to by {@code o} is an array, and the offset 117 * is an integer of the form {@code B+N*S}, where {@code N} is 118 * a valid index into the array, and {@code B} and {@code S} are 119 * the values obtained by {@link #arrayBaseOffset} and {@link 120 * #arrayIndexScale} (respectively) from the array's class. The value 121 * referred to is the {@code N}<em>th</em> element of the array. 122 * 123 * </ul> 124 * <p> 125 * If one of the above cases is true, the call references a specific Java 126 * variable (field or array element). However, the results are undefined 127 * if that variable is not in fact of the type returned by this method. 128 * <p> 129 * This method refers to a variable by means of two parameters, and so 130 * it provides (in effect) a <em>double-register</em> addressing mode 131 * for Java variables. When the object reference is null, this method 132 * uses its offset as an absolute address. This is similar in operation 133 * to methods such as {@link #getInt(long)}, which provide (in effect) a 134 * <em>single-register</em> addressing mode for non-Java variables. 135 * However, because Java variables may have a different layout in memory 136 * from non-Java variables, programmers should not assume that these 137 * two addressing modes are ever equivalent. Also, programmers should 138 * remember that offsets from the double-register addressing mode cannot 139 * be portably confused with longs used in the single-register addressing 140 * mode. 141 * 142 * @param o Java heap object in which the variable resides, if any, else 143 * null 144 * @param offset indication of where the variable resides in a Java heap 145 * object, if any, else a memory address locating the variable 146 * statically 147 * @return the value fetched from the indicated Java variable 148 * @throws RuntimeException No defined exceptions are thrown, not even 149 * {@link NullPointerException} 150 */ 151 @HotSpotIntrinsicCandidate 152 public native int getInt(Object o, long offset); 153 154 /** 155 * Stores a value into a given Java variable. 156 * <p> 157 * The first two parameters are interpreted exactly as with 158 * {@link #getInt(Object, long)} to refer to a specific 159 * Java variable (field or array element). The given value 160 * is stored into that variable. 161 * <p> 162 * The variable must be of the same type as the method 163 * parameter {@code x}. 164 * 165 * @param o Java heap object in which the variable resides, if any, else 166 * null 167 * @param offset indication of where the variable resides in a Java heap 168 * object, if any, else a memory address locating the variable 169 * statically 170 * @param x the value to store into the indicated Java variable 171 * @throws RuntimeException No defined exceptions are thrown, not even 172 * {@link NullPointerException} 173 */ 174 @HotSpotIntrinsicCandidate 175 public native void putInt(Object o, long offset, int x); 176 177 /** 178 * Fetches a reference value from a given Java variable. 179 * @see #getInt(Object, long) 180 */ 181 @HotSpotIntrinsicCandidate 182 public native Object getObject(Object o, long offset); 183 184 /** 185 * Stores a reference value into a given Java variable. 186 * <p> 187 * Unless the reference {@code x} being stored is either null 188 * or matches the field type, the results are undefined. 189 * If the reference {@code o} is non-null, card marks or 190 * other store barriers for that object (if the VM requires them) 191 * are updated. 192 * @see #putInt(Object, long, int) 193 */ 194 @HotSpotIntrinsicCandidate 195 public native void putObject(Object o, long offset, Object x); 196 197 /** @see #getInt(Object, long) */ 198 @HotSpotIntrinsicCandidate 199 public native boolean getBoolean(Object o, long offset); 200 201 /** @see #putInt(Object, long, int) */ 202 @HotSpotIntrinsicCandidate 203 public native void putBoolean(Object o, long offset, boolean x); 204 205 /** @see #getInt(Object, long) */ 206 @HotSpotIntrinsicCandidate 207 public native byte getByte(Object o, long offset); 208 209 /** @see #putInt(Object, long, int) */ 210 @HotSpotIntrinsicCandidate 211 public native void putByte(Object o, long offset, byte x); 212 213 /** @see #getInt(Object, long) */ 214 @HotSpotIntrinsicCandidate 215 public native short getShort(Object o, long offset); 216 217 /** @see #putInt(Object, long, int) */ 218 @HotSpotIntrinsicCandidate 219 public native void putShort(Object o, long offset, short x); 220 221 /** @see #getInt(Object, long) */ 222 @HotSpotIntrinsicCandidate 223 public native char getChar(Object o, long offset); 224 225 /** @see #putInt(Object, long, int) */ 226 @HotSpotIntrinsicCandidate 227 public native void putChar(Object o, long offset, char x); 228 229 /** @see #getInt(Object, long) */ 230 @HotSpotIntrinsicCandidate 231 public native long getLong(Object o, long offset); 232 233 /** @see #putInt(Object, long, int) */ 234 @HotSpotIntrinsicCandidate 235 public native void putLong(Object o, long offset, long x); 236 237 /** @see #getInt(Object, long) */ 238 @HotSpotIntrinsicCandidate 239 public native float getFloat(Object o, long offset); 240 241 /** @see #putInt(Object, long, int) */ 242 @HotSpotIntrinsicCandidate 243 public native void putFloat(Object o, long offset, float x); 244 245 /** @see #getInt(Object, long) */ 246 @HotSpotIntrinsicCandidate 247 public native double getDouble(Object o, long offset); 248 249 /** @see #putInt(Object, long, int) */ 250 @HotSpotIntrinsicCandidate 251 public native void putDouble(Object o, long offset, double x); 252 253 /** 254 * Fetches a native pointer from a given memory address. If the address is 255 * zero, or does not point into a block obtained from {@link 256 * #allocateMemory}, the results are undefined. 257 * 258 * <p>If the native pointer is less than 64 bits wide, it is extended as 259 * an unsigned number to a Java long. The pointer may be indexed by any 260 * given byte offset, simply by adding that offset (as a simple integer) to 261 * the long representing the pointer. The number of bytes actually read 262 * from the target address may be determined by consulting {@link 263 * #addressSize}. 264 * 265 * @see #allocateMemory 266 * @see #getInt(Object, long) 267 */ 268 @ForceInline 269 public long getAddress(Object o, long offset) { 270 if (ADDRESS_SIZE == 4) { 271 return Integer.toUnsignedLong(getInt(o, offset)); 272 } else { 273 return getLong(o, offset); 274 } 275 } 276 277 /** 278 * Stores a native pointer into a given memory address. If the address is 279 * zero, or does not point into a block obtained from {@link 280 * #allocateMemory}, the results are undefined. 281 * 282 * <p>The number of bytes actually written at the target address may be 283 * determined by consulting {@link #addressSize}. 284 * 285 * @see #allocateMemory 286 * @see #putInt(Object, long, int) 287 */ 288 @ForceInline 289 public void putAddress(Object o, long offset, long x) { 290 if (ADDRESS_SIZE == 4) { 291 putInt(o, offset, (int)x); 292 } else { 293 putLong(o, offset, x); 294 } 295 } 296 297 // These read VM internal data. 298 299 /** 300 * Fetches an uncompressed reference value from a given native variable 301 * ignoring the VM's compressed references mode. 302 * 303 * @param address a memory address locating the variable 304 * @return the value fetched from the indicated native variable 305 */ 306 public native Object getUncompressedObject(long address); 307 308 // These work on values in the C heap. 309 310 /** 311 * Fetches a value from a given memory address. If the address is zero, or 312 * does not point into a block obtained from {@link #allocateMemory}, the 313 * results are undefined. 314 * 315 * @see #allocateMemory 316 */ 317 @ForceInline 318 public byte getByte(long address) { 319 return getByte(null, address); 320 } 321 322 /** 323 * Stores a value into a given memory address. If the address is zero, or 324 * does not point into a block obtained from {@link #allocateMemory}, the 325 * results are undefined. 326 * 327 * @see #getByte(long) 328 */ 329 @ForceInline 330 public void putByte(long address, byte x) { 331 putByte(null, address, x); 332 } 333 334 /** @see #getByte(long) */ 335 @ForceInline 336 public short getShort(long address) { 337 return getShort(null, address); 338 } 339 340 /** @see #putByte(long, byte) */ 341 @ForceInline 342 public void putShort(long address, short x) { 343 putShort(null, address, x); 344 } 345 346 /** @see #getByte(long) */ 347 @ForceInline 348 public char getChar(long address) { 349 return getChar(null, address); 350 } 351 352 /** @see #putByte(long, byte) */ 353 @ForceInline 354 public void putChar(long address, char x) { 355 putChar(null, address, x); 356 } 357 358 /** @see #getByte(long) */ 359 @ForceInline 360 public int getInt(long address) { 361 return getInt(null, address); 362 } 363 364 /** @see #putByte(long, byte) */ 365 @ForceInline 366 public void putInt(long address, int x) { 367 putInt(null, address, x); 368 } 369 370 /** @see #getByte(long) */ 371 @ForceInline 372 public long getLong(long address) { 373 return getLong(null, address); 374 } 375 376 /** @see #putByte(long, byte) */ 377 @ForceInline 378 public void putLong(long address, long x) { 379 putLong(null, address, x); 380 } 381 382 /** @see #getByte(long) */ 383 @ForceInline 384 public float getFloat(long address) { 385 return getFloat(null, address); 386 } 387 388 /** @see #putByte(long, byte) */ 389 @ForceInline 390 public void putFloat(long address, float x) { 391 putFloat(null, address, x); 392 } 393 394 /** @see #getByte(long) */ 395 @ForceInline 396 public double getDouble(long address) { 397 return getDouble(null, address); 398 } 399 400 /** @see #putByte(long, byte) */ 401 @ForceInline 402 public void putDouble(long address, double x) { 403 putDouble(null, address, x); 404 } 405 406 /** @see #getAddress(Object, long) */ 407 @ForceInline 408 public long getAddress(long address) { 409 return getAddress(null, address); 410 } 411 412 /** @see #putAddress(Object, long, long) */ 413 @ForceInline 414 public void putAddress(long address, long x) { 415 putAddress(null, address, x); 416 } 417 418 419 420 /// helper methods for validating various types of objects/values 421 422 /** 423 * Create an exception reflecting that some of the input was invalid 424 * 425 * <em>Note:</em> It is the resposibility of the caller to make 426 * sure arguments are checked before the methods are called. While 427 * some rudimentary checks are performed on the input, the checks 428 * are best effort and when performance is an overriding priority, 429 * as when methods of this class are optimized by the runtime 430 * compiler, some or all checks (if any) may be elided. Hence, the 431 * caller must not rely on the checks and corresponding 432 * exceptions! 433 * 434 * @return an exception object 435 */ 436 private RuntimeException invalidInput() { 437 return new IllegalArgumentException(); 438 } 439 440 /** 441 * Check if a value is 32-bit clean (32 MSB are all zero) 442 * 443 * @param value the 64-bit value to check 444 * 445 * @return true if the value is 32-bit clean 446 */ 447 private boolean is32BitClean(long value) { 448 return value >>> 32 == 0; 449 } 450 451 /** 452 * Check the validity of a size (the equivalent of a size_t) 453 * 454 * @throws RuntimeException if the size is invalid 455 * (<em>Note:</em> after optimization, invalid inputs may 456 * go undetected, which will lead to unpredictable 457 * behavior) 458 */ 459 private void checkSize(long size) { 460 if (ADDRESS_SIZE == 4) { 461 // Note: this will also check for negative sizes 462 if (!is32BitClean(size)) { 463 throw invalidInput(); 464 } 465 } else if (size < 0) { 466 throw invalidInput(); 467 } 468 } 469 470 /** 471 * Check the validity of a native address (the equivalent of void*) 472 * 473 * @throws RuntimeException if the address is invalid 474 * (<em>Note:</em> after optimization, invalid inputs may 475 * go undetected, which will lead to unpredictable 476 * behavior) 477 */ 478 private void checkNativeAddress(long address) { 479 if (ADDRESS_SIZE == 4) { 480 // Accept both zero and sign extended pointers. A valid 481 // pointer will, after the +1 below, either have produced 482 // the value 0x0 or 0x1. Masking off the low bit allows 483 // for testing against 0. 484 if ((((address >> 32) + 1) & ~1) != 0) { 485 throw invalidInput(); 486 } 487 } 488 } 489 490 /** 491 * Check the validity of an offset, relative to a base object 492 * 493 * @param o the base object 494 * @param offset the offset to check 495 * 496 * @throws RuntimeException if the size is invalid 497 * (<em>Note:</em> after optimization, invalid inputs may 498 * go undetected, which will lead to unpredictable 499 * behavior) 500 */ 501 private void checkOffset(Object o, long offset) { 502 if (ADDRESS_SIZE == 4) { 503 // Note: this will also check for negative offsets 504 if (!is32BitClean(offset)) { 505 throw invalidInput(); 506 } 507 } else if (offset < 0) { 508 throw invalidInput(); 509 } 510 } 511 512 /** 513 * Check the validity of a double-register pointer 514 * 515 * Note: This code deliberately does *not* check for NPE for (at 516 * least) three reasons: 517 * 518 * 1) NPE is not just NULL/0 - there is a range of values all 519 * resulting in an NPE, which is not trivial to check for 520 * 521 * 2) It is the responsibility of the callers of Unsafe methods 522 * to verify the input, so throwing an exception here is not really 523 * useful - passing in a NULL pointer is a critical error and the 524 * must not expect an exception to be thrown anyway. 525 * 526 * 3) the actual operations will detect NULL pointers anyway by 527 * means of traps and signals (like SIGSEGV). 528 * 529 * @param o Java heap object, or null 530 * @param offset indication of where the variable resides in a Java heap 531 * object, if any, else a memory address locating the variable 532 * statically 533 * 534 * @throws RuntimeException if the pointer is invalid 535 * (<em>Note:</em> after optimization, invalid inputs may 536 * go undetected, which will lead to unpredictable 537 * behavior) 538 */ 539 private void checkPointer(Object o, long offset) { 540 if (o == null) { 541 checkNativeAddress(offset); 542 } else { 543 checkOffset(o, offset); 544 } 545 } 546 547 /** 548 * Check if a type is a primitive array type 549 * 550 * @param c the type to check 551 * 552 * @return true if the type is a primitive array type 553 */ 554 private void checkPrimitiveArray(Class<?> c) { 555 Class<?> componentType = c.getComponentType(); 556 if (componentType == null || !componentType.isPrimitive()) { 557 throw invalidInput(); 558 } 559 } 560 561 /** 562 * Check that a pointer is a valid primitive array type pointer 563 * 564 * Note: pointers off-heap are considered to be primitive arrays 565 * 566 * @throws RuntimeException if the pointer is invalid 567 * (<em>Note:</em> after optimization, invalid inputs may 568 * go undetected, which will lead to unpredictable 569 * behavior) 570 */ 571 private void checkPrimitivePointer(Object o, long offset) { 572 checkPointer(o, offset); 573 574 if (o != null) { 575 // If on heap, it it must be a primitive array 576 checkPrimitiveArray(o.getClass()); 577 } 578 } 579 580 581 /// wrappers for malloc, realloc, free: 582 583 /** 584 * Allocates a new block of native memory, of the given size in bytes. The 585 * contents of the memory are uninitialized; they will generally be 586 * garbage. The resulting native pointer will never be zero, and will be 587 * aligned for all value types. Dispose of this memory by calling {@link 588 * #freeMemory}, or resize it with {@link #reallocateMemory}. 589 * 590 * <em>Note:</em> It is the resposibility of the caller to make 591 * sure arguments are checked before the methods are called. While 592 * some rudimentary checks are performed on the input, the checks 593 * are best effort and when performance is an overriding priority, 594 * as when methods of this class are optimized by the runtime 595 * compiler, some or all checks (if any) may be elided. Hence, the 596 * caller must not rely on the checks and corresponding 597 * exceptions! 598 * 599 * @throws RuntimeException if the size is negative or too large 600 * for the native size_t type 601 * 602 * @throws OutOfMemoryError if the allocation is refused by the system 603 * 604 * @see #getByte(long) 605 * @see #putByte(long, byte) 606 */ 607 public long allocateMemory(long bytes) { 608 allocateMemoryChecks(bytes); 609 610 if (bytes == 0) { 611 return 0; 612 } 613 614 long p = allocateMemory0(bytes); 615 if (p == 0) { 616 throw new OutOfMemoryError(); 617 } 618 619 return p; 620 } 621 622 /** 623 * Validate the arguments to allocateMemory 624 * 625 * @throws RuntimeException if the arguments are invalid 626 * (<em>Note:</em> after optimization, invalid inputs may 627 * go undetected, which will lead to unpredictable 628 * behavior) 629 */ 630 private void allocateMemoryChecks(long bytes) { 631 checkSize(bytes); 632 } 633 634 /** 635 * Resizes a new block of native memory, to the given size in bytes. The 636 * contents of the new block past the size of the old block are 637 * uninitialized; they will generally be garbage. The resulting native 638 * pointer will be zero if and only if the requested size is zero. The 639 * resulting native pointer will be aligned for all value types. Dispose 640 * of this memory by calling {@link #freeMemory}, or resize it with {@link 641 * #reallocateMemory}. The address passed to this method may be null, in 642 * which case an allocation will be performed. 643 * 644 * <em>Note:</em> It is the resposibility of the caller to make 645 * sure arguments are checked before the methods are called. While 646 * some rudimentary checks are performed on the input, the checks 647 * are best effort and when performance is an overriding priority, 648 * as when methods of this class are optimized by the runtime 649 * compiler, some or all checks (if any) may be elided. Hence, the 650 * caller must not rely on the checks and corresponding 651 * exceptions! 652 * 653 * @throws RuntimeException if the size is negative or too large 654 * for the native size_t type 655 * 656 * @throws OutOfMemoryError if the allocation is refused by the system 657 * 658 * @see #allocateMemory 659 */ 660 public long reallocateMemory(long address, long bytes) { 661 reallocateMemoryChecks(address, bytes); 662 663 if (bytes == 0) { 664 freeMemory(address); 665 return 0; 666 } 667 668 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes); 669 if (p == 0) { 670 throw new OutOfMemoryError(); 671 } 672 673 return p; 674 } 675 676 /** 677 * Validate the arguments to reallocateMemory 678 * 679 * @throws RuntimeException if the arguments are invalid 680 * (<em>Note:</em> after optimization, invalid inputs may 681 * go undetected, which will lead to unpredictable 682 * behavior) 683 */ 684 private void reallocateMemoryChecks(long address, long bytes) { 685 checkPointer(null, address); 686 checkSize(bytes); 687 } 688 689 /** 690 * Sets all bytes in a given block of memory to a fixed value 691 * (usually zero). 692 * 693 * <p>This method determines a block's base address by means of two parameters, 694 * and so it provides (in effect) a <em>double-register</em> addressing mode, 695 * as discussed in {@link #getInt(Object,long)}. When the object reference is null, 696 * the offset supplies an absolute base address. 697 * 698 * <p>The stores are in coherent (atomic) units of a size determined 699 * by the address and length parameters. If the effective address and 700 * length are all even modulo 8, the stores take place in 'long' units. 701 * If the effective address and length are (resp.) even modulo 4 or 2, 702 * the stores take place in units of 'int' or 'short'. 703 * 704 * <em>Note:</em> It is the resposibility of the caller to make 705 * sure arguments are checked before the methods are called. While 706 * some rudimentary checks are performed on the input, the checks 707 * are best effort and when performance is an overriding priority, 708 * as when methods of this class are optimized by the runtime 709 * compiler, some or all checks (if any) may be elided. Hence, the 710 * caller must not rely on the checks and corresponding 711 * exceptions! 712 * 713 * @throws RuntimeException if any of the arguments is invalid 714 * 715 * @since 1.7 716 */ 717 public void setMemory(Object o, long offset, long bytes, byte value) { 718 setMemoryChecks(o, offset, bytes, value); 719 720 if (bytes == 0) { 721 return; 722 } 723 724 setMemory0(o, offset, bytes, value); 725 } 726 727 /** 728 * Sets all bytes in a given block of memory to a fixed value 729 * (usually zero). This provides a <em>single-register</em> addressing mode, 730 * as discussed in {@link #getInt(Object,long)}. 731 * 732 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}. 733 */ 734 public void setMemory(long address, long bytes, byte value) { 735 setMemory(null, address, bytes, value); 736 } 737 738 /** 739 * Validate the arguments to setMemory 740 * 741 * @throws RuntimeException if the arguments are invalid 742 * (<em>Note:</em> after optimization, invalid inputs may 743 * go undetected, which will lead to unpredictable 744 * behavior) 745 */ 746 private void setMemoryChecks(Object o, long offset, long bytes, byte value) { 747 checkPrimitivePointer(o, offset); 748 checkSize(bytes); 749 } 750 751 /** 752 * Sets all bytes in a given block of memory to a copy of another 753 * block. 754 * 755 * <p>This method determines each block's base address by means of two parameters, 756 * and so it provides (in effect) a <em>double-register</em> addressing mode, 757 * as discussed in {@link #getInt(Object,long)}. When the object reference is null, 758 * the offset supplies an absolute base address. 759 * 760 * <p>The transfers are in coherent (atomic) units of a size determined 761 * by the address and length parameters. If the effective addresses and 762 * length are all even modulo 8, the transfer takes place in 'long' units. 763 * If the effective addresses and length are (resp.) even modulo 4 or 2, 764 * the transfer takes place in units of 'int' or 'short'. 765 * 766 * <em>Note:</em> It is the resposibility of the caller to make 767 * sure arguments are checked before the methods are called. While 768 * some rudimentary checks are performed on the input, the checks 769 * are best effort and when performance is an overriding priority, 770 * as when methods of this class are optimized by the runtime 771 * compiler, some or all checks (if any) may be elided. Hence, the 772 * caller must not rely on the checks and corresponding 773 * exceptions! 774 * 775 * @throws RuntimeException if any of the arguments is invalid 776 * 777 * @since 1.7 778 */ 779 public void copyMemory(Object srcBase, long srcOffset, 780 Object destBase, long destOffset, 781 long bytes) { 782 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes); 783 784 if (bytes == 0) { 785 return; 786 } 787 788 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes); 789 } 790 791 /** 792 * Sets all bytes in a given block of memory to a copy of another 793 * block. This provides a <em>single-register</em> addressing mode, 794 * as discussed in {@link #getInt(Object,long)}. 795 * 796 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}. 797 */ 798 public void copyMemory(long srcAddress, long destAddress, long bytes) { 799 copyMemory(null, srcAddress, null, destAddress, bytes); 800 } 801 802 /** 803 * Validate the arguments to copyMemory 804 * 805 * @throws RuntimeException if any of the arguments is invalid 806 * (<em>Note:</em> after optimization, invalid inputs may 807 * go undetected, which will lead to unpredictable 808 * behavior) 809 */ 810 private void copyMemoryChecks(Object srcBase, long srcOffset, 811 Object destBase, long destOffset, 812 long bytes) { 813 checkSize(bytes); 814 checkPrimitivePointer(srcBase, srcOffset); 815 checkPrimitivePointer(destBase, destOffset); 816 } 817 818 /** 819 * Copies all elements from one block of memory to another block, 820 * *unconditionally* byte swapping the elements on the fly. 821 * 822 * <p>This method determines each block's base address by means of two parameters, 823 * and so it provides (in effect) a <em>double-register</em> addressing mode, 824 * as discussed in {@link #getInt(Object,long)}. When the object reference is null, 825 * the offset supplies an absolute base address. 826 * 827 * <em>Note:</em> It is the resposibility of the caller to make 828 * sure arguments are checked before the methods are called. While 829 * some rudimentary checks are performed on the input, the checks 830 * are best effort and when performance is an overriding priority, 831 * as when methods of this class are optimized by the runtime 832 * compiler, some or all checks (if any) may be elided. Hence, the 833 * caller must not rely on the checks and corresponding 834 * exceptions! 835 * 836 * @throws RuntimeException if any of the arguments is invalid 837 * 838 * @since 9 839 */ 840 public void copySwapMemory(Object srcBase, long srcOffset, 841 Object destBase, long destOffset, 842 long bytes, long elemSize) { 843 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize); 844 845 if (bytes == 0) { 846 return; 847 } 848 849 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize); 850 } 851 852 private void copySwapMemoryChecks(Object srcBase, long srcOffset, 853 Object destBase, long destOffset, 854 long bytes, long elemSize) { 855 checkSize(bytes); 856 857 if (elemSize != 2 && elemSize != 4 && elemSize != 8) { 858 throw invalidInput(); 859 } 860 if (bytes % elemSize != 0) { 861 throw invalidInput(); 862 } 863 864 checkPrimitivePointer(srcBase, srcOffset); 865 checkPrimitivePointer(destBase, destOffset); 866 } 867 868 /** 869 * Copies all elements from one block of memory to another block, byte swapping the 870 * elements on the fly. 871 * 872 * This provides a <em>single-register</em> addressing mode, as 873 * discussed in {@link #getInt(Object,long)}. 874 * 875 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}. 876 */ 877 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) { 878 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize); 879 } 880 881 /** 882 * Disposes of a block of native memory, as obtained from {@link 883 * #allocateMemory} or {@link #reallocateMemory}. The address passed to 884 * this method may be null, in which case no action is taken. 885 * 886 * <em>Note:</em> It is the resposibility of the caller to make 887 * sure arguments are checked before the methods are called. While 888 * some rudimentary checks are performed on the input, the checks 889 * are best effort and when performance is an overriding priority, 890 * as when methods of this class are optimized by the runtime 891 * compiler, some or all checks (if any) may be elided. Hence, the 892 * caller must not rely on the checks and corresponding 893 * exceptions! 894 * 895 * @throws RuntimeException if any of the arguments is invalid 896 * 897 * @see #allocateMemory 898 */ 899 public void freeMemory(long address) { 900 freeMemoryChecks(address); 901 902 if (address == 0) { 903 return; 904 } 905 906 freeMemory0(address); 907 } 908 909 /** 910 * Validate the arguments to freeMemory 911 * 912 * @throws RuntimeException if the arguments are invalid 913 * (<em>Note:</em> after optimization, invalid inputs may 914 * go undetected, which will lead to unpredictable 915 * behavior) 916 */ 917 private void freeMemoryChecks(long address) { 918 checkPointer(null, address); 919 } 920 921 /// random queries 922 923 /** 924 * This constant differs from all results that will ever be returned from 925 * {@link #staticFieldOffset}, {@link #objectFieldOffset}, 926 * or {@link #arrayBaseOffset}. 927 */ 928 public static final int INVALID_FIELD_OFFSET = -1; 929 930 /** 931 * Reports the location of a given field in the storage allocation of its 932 * class. Do not expect to perform any sort of arithmetic on this offset; 933 * it is just a cookie which is passed to the unsafe heap memory accessors. 934 * 935 * <p>Any given field will always have the same offset and base, and no 936 * two distinct fields of the same class will ever have the same offset 937 * and base. 938 * 939 * <p>As of 1.4.1, offsets for fields are represented as long values, 940 * although the Sun JVM does not use the most significant 32 bits. 941 * However, JVM implementations which store static fields at absolute 942 * addresses can use long offsets and null base pointers to express 943 * the field locations in a form usable by {@link #getInt(Object,long)}. 944 * Therefore, code which will be ported to such JVMs on 64-bit platforms 945 * must preserve all bits of static field offsets. 946 * @see #getInt(Object, long) 947 */ 948 public long objectFieldOffset(Field f) { 949 if (f == null) { 950 throw new NullPointerException(); 951 } 952 953 return objectFieldOffset0(f); 954 } 955 956 /** 957 * Reports the location of a given static field, in conjunction with {@link 958 * #staticFieldBase}. 959 * <p>Do not expect to perform any sort of arithmetic on this offset; 960 * it is just a cookie which is passed to the unsafe heap memory accessors. 961 * 962 * <p>Any given field will always have the same offset, and no two distinct 963 * fields of the same class will ever have the same offset. 964 * 965 * <p>As of 1.4.1, offsets for fields are represented as long values, 966 * although the Sun JVM does not use the most significant 32 bits. 967 * It is hard to imagine a JVM technology which needs more than 968 * a few bits to encode an offset within a non-array object, 969 * However, for consistency with other methods in this class, 970 * this method reports its result as a long value. 971 * @see #getInt(Object, long) 972 */ 973 public long staticFieldOffset(Field f) { 974 if (f == null) { 975 throw new NullPointerException(); 976 } 977 978 return staticFieldOffset0(f); 979 } 980 981 /** 982 * Reports the location of a given static field, in conjunction with {@link 983 * #staticFieldOffset}. 984 * <p>Fetch the base "Object", if any, with which static fields of the 985 * given class can be accessed via methods like {@link #getInt(Object, 986 * long)}. This value may be null. This value may refer to an object 987 * which is a "cookie", not guaranteed to be a real Object, and it should 988 * not be used in any way except as argument to the get and put routines in 989 * this class. 990 */ 991 public Object staticFieldBase(Field f) { 992 if (f == null) { 993 throw new NullPointerException(); 994 } 995 996 return staticFieldBase0(f); 997 } 998 999 /** 1000 * Detects if the given class may need to be initialized. This is often 1001 * needed in conjunction with obtaining the static field base of a 1002 * class. 1003 * @return false only if a call to {@code ensureClassInitialized} would have no effect 1004 */ 1005 public boolean shouldBeInitialized(Class<?> c) { 1006 if (c == null) { 1007 throw new NullPointerException(); 1008 } 1009 1010 return shouldBeInitialized0(c); 1011 } 1012 1013 /** 1014 * Ensures the given class has been initialized. This is often 1015 * needed in conjunction with obtaining the static field base of a 1016 * class. 1017 */ 1018 public void ensureClassInitialized(Class<?> c) { 1019 if (c == null) { 1020 throw new NullPointerException(); 1021 } 1022 1023 ensureClassInitialized0(c); 1024 } 1025 1026 /** 1027 * Reports the offset of the first element in the storage allocation of a 1028 * given array class. If {@link #arrayIndexScale} returns a non-zero value 1029 * for the same class, you may use that scale factor, together with this 1030 * base offset, to form new offsets to access elements of arrays of the 1031 * given class. 1032 * 1033 * @see #getInt(Object, long) 1034 * @see #putInt(Object, long, int) 1035 */ 1036 public int arrayBaseOffset(Class<?> arrayClass) { 1037 if (arrayClass == null) { 1038 throw new NullPointerException(); 1039 } 1040 1041 return arrayBaseOffset0(arrayClass); 1042 } 1043 1044 1045 /** The value of {@code arrayBaseOffset(boolean[].class)} */ 1046 public static final int ARRAY_BOOLEAN_BASE_OFFSET 1047 = theUnsafe.arrayBaseOffset(boolean[].class); 1048 1049 /** The value of {@code arrayBaseOffset(byte[].class)} */ 1050 public static final int ARRAY_BYTE_BASE_OFFSET 1051 = theUnsafe.arrayBaseOffset(byte[].class); 1052 1053 /** The value of {@code arrayBaseOffset(short[].class)} */ 1054 public static final int ARRAY_SHORT_BASE_OFFSET 1055 = theUnsafe.arrayBaseOffset(short[].class); 1056 1057 /** The value of {@code arrayBaseOffset(char[].class)} */ 1058 public static final int ARRAY_CHAR_BASE_OFFSET 1059 = theUnsafe.arrayBaseOffset(char[].class); 1060 1061 /** The value of {@code arrayBaseOffset(int[].class)} */ 1062 public static final int ARRAY_INT_BASE_OFFSET 1063 = theUnsafe.arrayBaseOffset(int[].class); 1064 1065 /** The value of {@code arrayBaseOffset(long[].class)} */ 1066 public static final int ARRAY_LONG_BASE_OFFSET 1067 = theUnsafe.arrayBaseOffset(long[].class); 1068 1069 /** The value of {@code arrayBaseOffset(float[].class)} */ 1070 public static final int ARRAY_FLOAT_BASE_OFFSET 1071 = theUnsafe.arrayBaseOffset(float[].class); 1072 1073 /** The value of {@code arrayBaseOffset(double[].class)} */ 1074 public static final int ARRAY_DOUBLE_BASE_OFFSET 1075 = theUnsafe.arrayBaseOffset(double[].class); 1076 1077 /** The value of {@code arrayBaseOffset(Object[].class)} */ 1078 public static final int ARRAY_OBJECT_BASE_OFFSET 1079 = theUnsafe.arrayBaseOffset(Object[].class); 1080 1081 /** 1082 * Reports the scale factor for addressing elements in the storage 1083 * allocation of a given array class. However, arrays of "narrow" types 1084 * will generally not work properly with accessors like {@link 1085 * #getByte(Object, long)}, so the scale factor for such classes is reported 1086 * as zero. 1087 * 1088 * @see #arrayBaseOffset 1089 * @see #getInt(Object, long) 1090 * @see #putInt(Object, long, int) 1091 */ 1092 public int arrayIndexScale(Class<?> arrayClass) { 1093 if (arrayClass == null) { 1094 throw new NullPointerException(); 1095 } 1096 1097 return arrayIndexScale0(arrayClass); 1098 } 1099 1100 1101 /** The value of {@code arrayIndexScale(boolean[].class)} */ 1102 public static final int ARRAY_BOOLEAN_INDEX_SCALE 1103 = theUnsafe.arrayIndexScale(boolean[].class); 1104 1105 /** The value of {@code arrayIndexScale(byte[].class)} */ 1106 public static final int ARRAY_BYTE_INDEX_SCALE 1107 = theUnsafe.arrayIndexScale(byte[].class); 1108 1109 /** The value of {@code arrayIndexScale(short[].class)} */ 1110 public static final int ARRAY_SHORT_INDEX_SCALE 1111 = theUnsafe.arrayIndexScale(short[].class); 1112 1113 /** The value of {@code arrayIndexScale(char[].class)} */ 1114 public static final int ARRAY_CHAR_INDEX_SCALE 1115 = theUnsafe.arrayIndexScale(char[].class); 1116 1117 /** The value of {@code arrayIndexScale(int[].class)} */ 1118 public static final int ARRAY_INT_INDEX_SCALE 1119 = theUnsafe.arrayIndexScale(int[].class); 1120 1121 /** The value of {@code arrayIndexScale(long[].class)} */ 1122 public static final int ARRAY_LONG_INDEX_SCALE 1123 = theUnsafe.arrayIndexScale(long[].class); 1124 1125 /** The value of {@code arrayIndexScale(float[].class)} */ 1126 public static final int ARRAY_FLOAT_INDEX_SCALE 1127 = theUnsafe.arrayIndexScale(float[].class); 1128 1129 /** The value of {@code arrayIndexScale(double[].class)} */ 1130 public static final int ARRAY_DOUBLE_INDEX_SCALE 1131 = theUnsafe.arrayIndexScale(double[].class); 1132 1133 /** The value of {@code arrayIndexScale(Object[].class)} */ 1134 public static final int ARRAY_OBJECT_INDEX_SCALE 1135 = theUnsafe.arrayIndexScale(Object[].class); 1136 1137 /** 1138 * Reports the size in bytes of a native pointer, as stored via {@link 1139 * #putAddress}. This value will be either 4 or 8. Note that the sizes of 1140 * other primitive types (as stored in native memory blocks) is determined 1141 * fully by their information content. 1142 */ 1143 public int addressSize() { 1144 return ADDRESS_SIZE; 1145 } 1146 1147 /** The value of {@code addressSize()} */ 1148 public static final int ADDRESS_SIZE = theUnsafe.addressSize0(); 1149 1150 /** 1151 * Reports the size in bytes of a native memory page (whatever that is). 1152 * This value will always be a power of two. 1153 */ 1154 public native int pageSize(); 1155 1156 1157 /// random trusted operations from JNI: 1158 1159 /** 1160 * Tells the VM to define a class, without security checks. By default, the 1161 * class loader and protection domain come from the caller's class. 1162 */ 1163 public Class<?> defineClass(String name, byte[] b, int off, int len, 1164 ClassLoader loader, 1165 ProtectionDomain protectionDomain) { 1166 if (b == null) { 1167 throw new NullPointerException(); 1168 } 1169 if (len < 0) { 1170 throw new ArrayIndexOutOfBoundsException(); 1171 } 1172 1173 return defineClass0(name, b, off, len, loader, protectionDomain); 1174 } 1175 1176 public native Class<?> defineClass0(String name, byte[] b, int off, int len, 1177 ClassLoader loader, 1178 ProtectionDomain protectionDomain); 1179 1180 /** 1181 * Defines a class but does not make it known to the class loader or system dictionary. 1182 * <p> 1183 * For each CP entry, the corresponding CP patch must either be null or have 1184 * the a format that matches its tag: 1185 * <ul> 1186 * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang 1187 * <li>Utf8: a string (must have suitable syntax if used as signature or name) 1188 * <li>Class: any java.lang.Class object 1189 * <li>String: any object (not just a java.lang.String) 1190 * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments 1191 * </ul> 1192 * @param hostClass context for linkage, access control, protection domain, and class loader 1193 * @param data bytes of a class file 1194 * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data 1195 */ 1196 public Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches) { 1197 if (hostClass == null || data == null) { 1198 throw new NullPointerException(); 1199 } 1200 if (hostClass.isArray() || hostClass.isPrimitive()) { 1201 throw new IllegalArgumentException(); 1202 } 1203 1204 return defineAnonymousClass0(hostClass, data, cpPatches); 1205 } 1206 1207 /** 1208 * Allocates an instance but does not run any constructor. 1209 * Initializes the class if it has not yet been. 1210 */ 1211 @HotSpotIntrinsicCandidate 1212 public native Object allocateInstance(Class<?> cls) 1213 throws InstantiationException; 1214 1215 /** 1216 * Allocates an array of a given type, but does not do zeroing. 1217 * <p> 1218 * This method should only be used in the very rare cases where a high-performance code 1219 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination. 1220 * In an overwhelming majority of cases, a normal Java allocation should be used instead. 1221 * <p> 1222 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents 1223 * before allowing untrusted code, or code in other threads, to observe the reference 1224 * to the newly allocated array. In addition, the publication of the array reference must be 1225 * safe according to the Java Memory Model requirements. 1226 * <p> 1227 * The safest approach to deal with an uninitialized array is to keep the reference to it in local 1228 * variable at least until the initialization is complete, and then publish it <b>once</b>, either 1229 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor, 1230 * or issuing a {@link #storeFence} before publishing the reference. 1231 * <p> 1232 * @implnote This method can only allocate primitive arrays, to avoid garbage reference 1233 * elements that could break heap integrity. 1234 * 1235 * @param componentType array component type to allocate 1236 * @param length array size to allocate 1237 * @throws IllegalArgumentException if component type is null, or not a primitive class; 1238 * or the length is negative 1239 */ 1240 public Object allocateUninitializedArray(Class<?> componentType, int length) { 1241 if (componentType == null) { 1242 throw new IllegalArgumentException("Component type is null"); 1243 } 1244 if (!componentType.isPrimitive()) { 1245 throw new IllegalArgumentException("Component type is not primitive"); 1246 } 1247 if (length < 0) { 1248 throw new IllegalArgumentException("Negative length"); 1249 } 1250 return allocateUninitializedArray0(componentType, length); 1251 } 1252 1253 @HotSpotIntrinsicCandidate 1254 private Object allocateUninitializedArray0(Class<?> componentType, int length) { 1255 // These fallbacks provide zeroed arrays, but intrinsic is not required to 1256 // return the zeroed arrays. 1257 if (componentType == byte.class) return new byte[length]; 1258 if (componentType == boolean.class) return new boolean[length]; 1259 if (componentType == short.class) return new short[length]; 1260 if (componentType == char.class) return new char[length]; 1261 if (componentType == int.class) return new int[length]; 1262 if (componentType == float.class) return new float[length]; 1263 if (componentType == long.class) return new long[length]; 1264 if (componentType == double.class) return new double[length]; 1265 return null; 1266 } 1267 1268 /** Throws the exception without telling the verifier. */ 1269 public native void throwException(Throwable ee); 1270 1271 /** 1272 * Atomically updates Java variable to {@code x} if it is currently 1273 * holding {@code expected}. 1274 * 1275 * <p>This operation has memory semantics of a {@code volatile} read 1276 * and write. Corresponds to C11 atomic_compare_exchange_strong. 1277 * 1278 * @return {@code true} if successful 1279 */ 1280 @HotSpotIntrinsicCandidate 1281 public final native boolean compareAndSetObject(Object o, long offset, 1282 Object expected, 1283 Object x); 1284 1285 @HotSpotIntrinsicCandidate 1286 public final native Object compareAndExchangeObject(Object o, long offset, 1287 Object expected, 1288 Object x); 1289 1290 @HotSpotIntrinsicCandidate 1291 public final Object compareAndExchangeObjectAcquire(Object o, long offset, 1292 Object expected, 1293 Object x) { 1294 return compareAndExchangeObject(o, offset, expected, x); 1295 } 1296 1297 @HotSpotIntrinsicCandidate 1298 public final Object compareAndExchangeObjectRelease(Object o, long offset, 1299 Object expected, 1300 Object x) { 1301 return compareAndExchangeObject(o, offset, expected, x); 1302 } 1303 1304 @HotSpotIntrinsicCandidate 1305 public final boolean weakCompareAndSetObjectPlain(Object o, long offset, 1306 Object expected, 1307 Object x) { 1308 return compareAndSetObject(o, offset, expected, x); 1309 } 1310 1311 @HotSpotIntrinsicCandidate 1312 public final boolean weakCompareAndSetObjectAcquire(Object o, long offset, 1313 Object expected, 1314 Object x) { 1315 return compareAndSetObject(o, offset, expected, x); 1316 } 1317 1318 @HotSpotIntrinsicCandidate 1319 public final boolean weakCompareAndSetObjectRelease(Object o, long offset, 1320 Object expected, 1321 Object x) { 1322 return compareAndSetObject(o, offset, expected, x); 1323 } 1324 1325 @HotSpotIntrinsicCandidate 1326 public final boolean weakCompareAndSetObject(Object o, long offset, 1327 Object expected, 1328 Object x) { 1329 return compareAndSetObject(o, offset, expected, x); 1330 } 1331 1332 /** 1333 * Atomically updates Java variable to {@code x} if it is currently 1334 * holding {@code expected}. 1335 * 1336 * <p>This operation has memory semantics of a {@code volatile} read 1337 * and write. Corresponds to C11 atomic_compare_exchange_strong. 1338 * 1339 * @return {@code true} if successful 1340 */ 1341 @HotSpotIntrinsicCandidate 1342 public final native boolean compareAndSetInt(Object o, long offset, 1343 int expected, 1344 int x); 1345 1346 @HotSpotIntrinsicCandidate 1347 public final native int compareAndExchangeInt(Object o, long offset, 1348 int expected, 1349 int x); 1350 1351 @HotSpotIntrinsicCandidate 1352 public final int compareAndExchangeIntAcquire(Object o, long offset, 1353 int expected, 1354 int x) { 1355 return compareAndExchangeInt(o, offset, expected, x); 1356 } 1357 1358 @HotSpotIntrinsicCandidate 1359 public final int compareAndExchangeIntRelease(Object o, long offset, 1360 int expected, 1361 int x) { 1362 return compareAndExchangeInt(o, offset, expected, x); 1363 } 1364 1365 @HotSpotIntrinsicCandidate 1366 public final boolean weakCompareAndSetIntPlain(Object o, long offset, 1367 int expected, 1368 int x) { 1369 return compareAndSetInt(o, offset, expected, x); 1370 } 1371 1372 @HotSpotIntrinsicCandidate 1373 public final boolean weakCompareAndSetIntAcquire(Object o, long offset, 1374 int expected, 1375 int x) { 1376 return compareAndSetInt(o, offset, expected, x); 1377 } 1378 1379 @HotSpotIntrinsicCandidate 1380 public final boolean weakCompareAndSetIntRelease(Object o, long offset, 1381 int expected, 1382 int x) { 1383 return compareAndSetInt(o, offset, expected, x); 1384 } 1385 1386 @HotSpotIntrinsicCandidate 1387 public final boolean weakCompareAndSetInt(Object o, long offset, 1388 int expected, 1389 int x) { 1390 return compareAndSetInt(o, offset, expected, x); 1391 } 1392 1393 @HotSpotIntrinsicCandidate 1394 public final byte compareAndExchangeByte(Object o, long offset, 1395 byte expected, 1396 byte x) { 1397 long wordOffset = offset & ~3; 1398 int shift = (int) (offset & 3) << 3; 1399 if (BE) { 1400 shift = 24 - shift; 1401 } 1402 int mask = 0xFF << shift; 1403 int maskedExpected = (expected & 0xFF) << shift; 1404 int maskedX = (x & 0xFF) << shift; 1405 int fullWord; 1406 do { 1407 fullWord = getIntVolatile(o, wordOffset); 1408 if ((fullWord & mask) != maskedExpected) 1409 return (byte) ((fullWord & mask) >> shift); 1410 } while (!weakCompareAndSetInt(o, wordOffset, 1411 fullWord, (fullWord & ~mask) | maskedX)); 1412 return expected; 1413 } 1414 1415 @HotSpotIntrinsicCandidate 1416 public final boolean compareAndSetByte(Object o, long offset, 1417 byte expected, 1418 byte x) { 1419 return compareAndExchangeByte(o, offset, expected, x) == expected; 1420 } 1421 1422 @HotSpotIntrinsicCandidate 1423 public final boolean weakCompareAndSetByte(Object o, long offset, 1424 byte expected, 1425 byte x) { 1426 return compareAndSetByte(o, offset, expected, x); 1427 } 1428 1429 @HotSpotIntrinsicCandidate 1430 public final boolean weakCompareAndSetByteAcquire(Object o, long offset, 1431 byte expected, 1432 byte x) { 1433 return weakCompareAndSetByte(o, offset, expected, x); 1434 } 1435 1436 @HotSpotIntrinsicCandidate 1437 public final boolean weakCompareAndSetByteRelease(Object o, long offset, 1438 byte expected, 1439 byte x) { 1440 return weakCompareAndSetByte(o, offset, expected, x); 1441 } 1442 1443 @HotSpotIntrinsicCandidate 1444 public final boolean weakCompareAndSetBytePlain(Object o, long offset, 1445 byte expected, 1446 byte x) { 1447 return weakCompareAndSetByte(o, offset, expected, x); 1448 } 1449 1450 @HotSpotIntrinsicCandidate 1451 public final byte compareAndExchangeByteAcquire(Object o, long offset, 1452 byte expected, 1453 byte x) { 1454 return compareAndExchangeByte(o, offset, expected, x); 1455 } 1456 1457 @HotSpotIntrinsicCandidate 1458 public final byte compareAndExchangeByteRelease(Object o, long offset, 1459 byte expected, 1460 byte x) { 1461 return compareAndExchangeByte(o, offset, expected, x); 1462 } 1463 1464 @HotSpotIntrinsicCandidate 1465 public final short compareAndExchangeShort(Object o, long offset, 1466 short expected, 1467 short x) { 1468 if ((offset & 3) == 3) { 1469 throw new IllegalArgumentException("Update spans the word, not supported"); 1470 } 1471 long wordOffset = offset & ~3; 1472 int shift = (int) (offset & 3) << 3; 1473 if (BE) { 1474 shift = 16 - shift; 1475 } 1476 int mask = 0xFFFF << shift; 1477 int maskedExpected = (expected & 0xFFFF) << shift; 1478 int maskedX = (x & 0xFFFF) << shift; 1479 int fullWord; 1480 do { 1481 fullWord = getIntVolatile(o, wordOffset); 1482 if ((fullWord & mask) != maskedExpected) { 1483 return (short) ((fullWord & mask) >> shift); 1484 } 1485 } while (!weakCompareAndSetInt(o, wordOffset, 1486 fullWord, (fullWord & ~mask) | maskedX)); 1487 return expected; 1488 } 1489 1490 @HotSpotIntrinsicCandidate 1491 public final boolean compareAndSetShort(Object o, long offset, 1492 short expected, 1493 short x) { 1494 return compareAndExchangeShort(o, offset, expected, x) == expected; 1495 } 1496 1497 @HotSpotIntrinsicCandidate 1498 public final boolean weakCompareAndSetShort(Object o, long offset, 1499 short expected, 1500 short x) { 1501 return compareAndSetShort(o, offset, expected, x); 1502 } 1503 1504 @HotSpotIntrinsicCandidate 1505 public final boolean weakCompareAndSetShortAcquire(Object o, long offset, 1506 short expected, 1507 short x) { 1508 return weakCompareAndSetShort(o, offset, expected, x); 1509 } 1510 1511 @HotSpotIntrinsicCandidate 1512 public final boolean weakCompareAndSetShortRelease(Object o, long offset, 1513 short expected, 1514 short x) { 1515 return weakCompareAndSetShort(o, offset, expected, x); 1516 } 1517 1518 @HotSpotIntrinsicCandidate 1519 public final boolean weakCompareAndSetShortPlain(Object o, long offset, 1520 short expected, 1521 short x) { 1522 return weakCompareAndSetShort(o, offset, expected, x); 1523 } 1524 1525 1526 @HotSpotIntrinsicCandidate 1527 public final short compareAndExchangeShortAcquire(Object o, long offset, 1528 short expected, 1529 short x) { 1530 return compareAndExchangeShort(o, offset, expected, x); 1531 } 1532 1533 @HotSpotIntrinsicCandidate 1534 public final short compareAndExchangeShortRelease(Object o, long offset, 1535 short expected, 1536 short x) { 1537 return compareAndExchangeShort(o, offset, expected, x); 1538 } 1539 1540 @ForceInline 1541 private char s2c(short s) { 1542 return (char) s; 1543 } 1544 1545 @ForceInline 1546 private short c2s(char s) { 1547 return (short) s; 1548 } 1549 1550 @ForceInline 1551 public final boolean compareAndSetChar(Object o, long offset, 1552 char expected, 1553 char x) { 1554 return compareAndSetShort(o, offset, c2s(expected), c2s(x)); 1555 } 1556 1557 @ForceInline 1558 public final char compareAndExchangeChar(Object o, long offset, 1559 char expected, 1560 char x) { 1561 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x))); 1562 } 1563 1564 @ForceInline 1565 public final char compareAndExchangeCharAcquire(Object o, long offset, 1566 char expected, 1567 char x) { 1568 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x))); 1569 } 1570 1571 @ForceInline 1572 public final char compareAndExchangeCharRelease(Object o, long offset, 1573 char expected, 1574 char x) { 1575 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x))); 1576 } 1577 1578 @ForceInline 1579 public final boolean weakCompareAndSetChar(Object o, long offset, 1580 char expected, 1581 char x) { 1582 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x)); 1583 } 1584 1585 @ForceInline 1586 public final boolean weakCompareAndSetCharAcquire(Object o, long offset, 1587 char expected, 1588 char x) { 1589 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x)); 1590 } 1591 1592 @ForceInline 1593 public final boolean weakCompareAndSetCharRelease(Object o, long offset, 1594 char expected, 1595 char x) { 1596 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x)); 1597 } 1598 1599 @ForceInline 1600 public final boolean weakCompareAndSetCharPlain(Object o, long offset, 1601 char expected, 1602 char x) { 1603 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x)); 1604 } 1605 1606 /** 1607 * The JVM converts integral values to boolean values using two 1608 * different conventions, byte testing against zero and truncation 1609 * to least-significant bit. 1610 * 1611 * <p>The JNI documents specify that, at least for returning 1612 * values from native methods, a Java boolean value is converted 1613 * to the value-set 0..1 by first truncating to a byte (0..255 or 1614 * maybe -128..127) and then testing against zero. Thus, Java 1615 * booleans in non-Java data structures are by convention 1616 * represented as 8-bit containers containing either zero (for 1617 * false) or any non-zero value (for true). 1618 * 1619 * <p>Java booleans in the heap are also stored in bytes, but are 1620 * strongly normalized to the value-set 0..1 (i.e., they are 1621 * truncated to the least-significant bit). 1622 * 1623 * <p>The main reason for having different conventions for 1624 * conversion is performance: Truncation to the least-significant 1625 * bit can be usually implemented with fewer (machine) 1626 * instructions than byte testing against zero. 1627 * 1628 * <p>A number of Unsafe methods load boolean values from the heap 1629 * as bytes. Unsafe converts those values according to the JNI 1630 * rules (i.e, using the "testing against zero" convention). The 1631 * method {@code byte2bool} implements that conversion. 1632 * 1633 * @param b the byte to be converted to boolean 1634 * @return the result of the conversion 1635 */ 1636 @ForceInline 1637 private boolean byte2bool(byte b) { 1638 return b != 0; 1639 } 1640 1641 /** 1642 * Convert a boolean value to a byte. The return value is strongly 1643 * normalized to the value-set 0..1 (i.e., the value is truncated 1644 * to the least-significant bit). See {@link #byte2bool(byte)} for 1645 * more details on conversion conventions. 1646 * 1647 * @param b the boolean to be converted to byte (and then normalized) 1648 * @return the result of the conversion 1649 */ 1650 @ForceInline 1651 private byte bool2byte(boolean b) { 1652 return b ? (byte)1 : (byte)0; 1653 } 1654 1655 @ForceInline 1656 public final boolean compareAndSetBoolean(Object o, long offset, 1657 boolean expected, 1658 boolean x) { 1659 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x)); 1660 } 1661 1662 @ForceInline 1663 public final boolean compareAndExchangeBoolean(Object o, long offset, 1664 boolean expected, 1665 boolean x) { 1666 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x))); 1667 } 1668 1669 @ForceInline 1670 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset, 1671 boolean expected, 1672 boolean x) { 1673 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x))); 1674 } 1675 1676 @ForceInline 1677 public final boolean compareAndExchangeBooleanRelease(Object o, long offset, 1678 boolean expected, 1679 boolean x) { 1680 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x))); 1681 } 1682 1683 @ForceInline 1684 public final boolean weakCompareAndSetBoolean(Object o, long offset, 1685 boolean expected, 1686 boolean x) { 1687 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x)); 1688 } 1689 1690 @ForceInline 1691 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset, 1692 boolean expected, 1693 boolean x) { 1694 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x)); 1695 } 1696 1697 @ForceInline 1698 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset, 1699 boolean expected, 1700 boolean x) { 1701 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x)); 1702 } 1703 1704 @ForceInline 1705 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset, 1706 boolean expected, 1707 boolean x) { 1708 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x)); 1709 } 1710 1711 /** 1712 * Atomically updates Java variable to {@code x} if it is currently 1713 * holding {@code expected}. 1714 * 1715 * <p>This operation has memory semantics of a {@code volatile} read 1716 * and write. Corresponds to C11 atomic_compare_exchange_strong. 1717 * 1718 * @return {@code true} if successful 1719 */ 1720 @ForceInline 1721 public final boolean compareAndSetFloat(Object o, long offset, 1722 float expected, 1723 float x) { 1724 return compareAndSetInt(o, offset, 1725 Float.floatToRawIntBits(expected), 1726 Float.floatToRawIntBits(x)); 1727 } 1728 1729 @ForceInline 1730 public final float compareAndExchangeFloat(Object o, long offset, 1731 float expected, 1732 float x) { 1733 int w = compareAndExchangeInt(o, offset, 1734 Float.floatToRawIntBits(expected), 1735 Float.floatToRawIntBits(x)); 1736 return Float.intBitsToFloat(w); 1737 } 1738 1739 @ForceInline 1740 public final float compareAndExchangeFloatAcquire(Object o, long offset, 1741 float expected, 1742 float x) { 1743 int w = compareAndExchangeIntAcquire(o, offset, 1744 Float.floatToRawIntBits(expected), 1745 Float.floatToRawIntBits(x)); 1746 return Float.intBitsToFloat(w); 1747 } 1748 1749 @ForceInline 1750 public final float compareAndExchangeFloatRelease(Object o, long offset, 1751 float expected, 1752 float x) { 1753 int w = compareAndExchangeIntRelease(o, offset, 1754 Float.floatToRawIntBits(expected), 1755 Float.floatToRawIntBits(x)); 1756 return Float.intBitsToFloat(w); 1757 } 1758 1759 @ForceInline 1760 public final boolean weakCompareAndSetFloatPlain(Object o, long offset, 1761 float expected, 1762 float x) { 1763 return weakCompareAndSetIntPlain(o, offset, 1764 Float.floatToRawIntBits(expected), 1765 Float.floatToRawIntBits(x)); 1766 } 1767 1768 @ForceInline 1769 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset, 1770 float expected, 1771 float x) { 1772 return weakCompareAndSetIntAcquire(o, offset, 1773 Float.floatToRawIntBits(expected), 1774 Float.floatToRawIntBits(x)); 1775 } 1776 1777 @ForceInline 1778 public final boolean weakCompareAndSetFloatRelease(Object o, long offset, 1779 float expected, 1780 float x) { 1781 return weakCompareAndSetIntRelease(o, offset, 1782 Float.floatToRawIntBits(expected), 1783 Float.floatToRawIntBits(x)); 1784 } 1785 1786 @ForceInline 1787 public final boolean weakCompareAndSetFloat(Object o, long offset, 1788 float expected, 1789 float x) { 1790 return weakCompareAndSetInt(o, offset, 1791 Float.floatToRawIntBits(expected), 1792 Float.floatToRawIntBits(x)); 1793 } 1794 1795 /** 1796 * Atomically updates Java variable to {@code x} if it is currently 1797 * holding {@code expected}. 1798 * 1799 * <p>This operation has memory semantics of a {@code volatile} read 1800 * and write. Corresponds to C11 atomic_compare_exchange_strong. 1801 * 1802 * @return {@code true} if successful 1803 */ 1804 @ForceInline 1805 public final boolean compareAndSetDouble(Object o, long offset, 1806 double expected, 1807 double x) { 1808 return compareAndSetLong(o, offset, 1809 Double.doubleToRawLongBits(expected), 1810 Double.doubleToRawLongBits(x)); 1811 } 1812 1813 @ForceInline 1814 public final double compareAndExchangeDouble(Object o, long offset, 1815 double expected, 1816 double x) { 1817 long w = compareAndExchangeLong(o, offset, 1818 Double.doubleToRawLongBits(expected), 1819 Double.doubleToRawLongBits(x)); 1820 return Double.longBitsToDouble(w); 1821 } 1822 1823 @ForceInline 1824 public final double compareAndExchangeDoubleAcquire(Object o, long offset, 1825 double expected, 1826 double x) { 1827 long w = compareAndExchangeLongAcquire(o, offset, 1828 Double.doubleToRawLongBits(expected), 1829 Double.doubleToRawLongBits(x)); 1830 return Double.longBitsToDouble(w); 1831 } 1832 1833 @ForceInline 1834 public final double compareAndExchangeDoubleRelease(Object o, long offset, 1835 double expected, 1836 double x) { 1837 long w = compareAndExchangeLongRelease(o, offset, 1838 Double.doubleToRawLongBits(expected), 1839 Double.doubleToRawLongBits(x)); 1840 return Double.longBitsToDouble(w); 1841 } 1842 1843 @ForceInline 1844 public final boolean weakCompareAndSetDoublePlain(Object o, long offset, 1845 double expected, 1846 double x) { 1847 return weakCompareAndSetLongPlain(o, offset, 1848 Double.doubleToRawLongBits(expected), 1849 Double.doubleToRawLongBits(x)); 1850 } 1851 1852 @ForceInline 1853 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset, 1854 double expected, 1855 double x) { 1856 return weakCompareAndSetLongAcquire(o, offset, 1857 Double.doubleToRawLongBits(expected), 1858 Double.doubleToRawLongBits(x)); 1859 } 1860 1861 @ForceInline 1862 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset, 1863 double expected, 1864 double x) { 1865 return weakCompareAndSetLongRelease(o, offset, 1866 Double.doubleToRawLongBits(expected), 1867 Double.doubleToRawLongBits(x)); 1868 } 1869 1870 @ForceInline 1871 public final boolean weakCompareAndSetDouble(Object o, long offset, 1872 double expected, 1873 double x) { 1874 return weakCompareAndSetLong(o, offset, 1875 Double.doubleToRawLongBits(expected), 1876 Double.doubleToRawLongBits(x)); 1877 } 1878 1879 /** 1880 * Atomically updates Java variable to {@code x} if it is currently 1881 * holding {@code expected}. 1882 * 1883 * <p>This operation has memory semantics of a {@code volatile} read 1884 * and write. Corresponds to C11 atomic_compare_exchange_strong. 1885 * 1886 * @return {@code true} if successful 1887 */ 1888 @HotSpotIntrinsicCandidate 1889 public final native boolean compareAndSetLong(Object o, long offset, 1890 long expected, 1891 long x); 1892 1893 @HotSpotIntrinsicCandidate 1894 public final native long compareAndExchangeLong(Object o, long offset, 1895 long expected, 1896 long x); 1897 1898 @HotSpotIntrinsicCandidate 1899 public final long compareAndExchangeLongAcquire(Object o, long offset, 1900 long expected, 1901 long x) { 1902 return compareAndExchangeLong(o, offset, expected, x); 1903 } 1904 1905 @HotSpotIntrinsicCandidate 1906 public final long compareAndExchangeLongRelease(Object o, long offset, 1907 long expected, 1908 long x) { 1909 return compareAndExchangeLong(o, offset, expected, x); 1910 } 1911 1912 @HotSpotIntrinsicCandidate 1913 public final boolean weakCompareAndSetLongPlain(Object o, long offset, 1914 long expected, 1915 long x) { 1916 return compareAndSetLong(o, offset, expected, x); 1917 } 1918 1919 @HotSpotIntrinsicCandidate 1920 public final boolean weakCompareAndSetLongAcquire(Object o, long offset, 1921 long expected, 1922 long x) { 1923 return compareAndSetLong(o, offset, expected, x); 1924 } 1925 1926 @HotSpotIntrinsicCandidate 1927 public final boolean weakCompareAndSetLongRelease(Object o, long offset, 1928 long expected, 1929 long x) { 1930 return compareAndSetLong(o, offset, expected, x); 1931 } 1932 1933 @HotSpotIntrinsicCandidate 1934 public final boolean weakCompareAndSetLong(Object o, long offset, 1935 long expected, 1936 long x) { 1937 return compareAndSetLong(o, offset, expected, x); 1938 } 1939 1940 /** 1941 * Fetches a reference value from a given Java variable, with volatile 1942 * load semantics. Otherwise identical to {@link #getObject(Object, long)} 1943 */ 1944 @HotSpotIntrinsicCandidate 1945 public native Object getObjectVolatile(Object o, long offset); 1946 1947 /** 1948 * Stores a reference value into a given Java variable, with 1949 * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)} 1950 */ 1951 @HotSpotIntrinsicCandidate 1952 public native void putObjectVolatile(Object o, long offset, Object x); 1953 1954 /** Volatile version of {@link #getInt(Object, long)} */ 1955 @HotSpotIntrinsicCandidate 1956 public native int getIntVolatile(Object o, long offset); 1957 1958 /** Volatile version of {@link #putInt(Object, long, int)} */ 1959 @HotSpotIntrinsicCandidate 1960 public native void putIntVolatile(Object o, long offset, int x); 1961 1962 /** Volatile version of {@link #getBoolean(Object, long)} */ 1963 @HotSpotIntrinsicCandidate 1964 public native boolean getBooleanVolatile(Object o, long offset); 1965 1966 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */ 1967 @HotSpotIntrinsicCandidate 1968 public native void putBooleanVolatile(Object o, long offset, boolean x); 1969 1970 /** Volatile version of {@link #getByte(Object, long)} */ 1971 @HotSpotIntrinsicCandidate 1972 public native byte getByteVolatile(Object o, long offset); 1973 1974 /** Volatile version of {@link #putByte(Object, long, byte)} */ 1975 @HotSpotIntrinsicCandidate 1976 public native void putByteVolatile(Object o, long offset, byte x); 1977 1978 /** Volatile version of {@link #getShort(Object, long)} */ 1979 @HotSpotIntrinsicCandidate 1980 public native short getShortVolatile(Object o, long offset); 1981 1982 /** Volatile version of {@link #putShort(Object, long, short)} */ 1983 @HotSpotIntrinsicCandidate 1984 public native void putShortVolatile(Object o, long offset, short x); 1985 1986 /** Volatile version of {@link #getChar(Object, long)} */ 1987 @HotSpotIntrinsicCandidate 1988 public native char getCharVolatile(Object o, long offset); 1989 1990 /** Volatile version of {@link #putChar(Object, long, char)} */ 1991 @HotSpotIntrinsicCandidate 1992 public native void putCharVolatile(Object o, long offset, char x); 1993 1994 /** Volatile version of {@link #getLong(Object, long)} */ 1995 @HotSpotIntrinsicCandidate 1996 public native long getLongVolatile(Object o, long offset); 1997 1998 /** Volatile version of {@link #putLong(Object, long, long)} */ 1999 @HotSpotIntrinsicCandidate 2000 public native void putLongVolatile(Object o, long offset, long x); 2001 2002 /** Volatile version of {@link #getFloat(Object, long)} */ 2003 @HotSpotIntrinsicCandidate 2004 public native float getFloatVolatile(Object o, long offset); 2005 2006 /** Volatile version of {@link #putFloat(Object, long, float)} */ 2007 @HotSpotIntrinsicCandidate 2008 public native void putFloatVolatile(Object o, long offset, float x); 2009 2010 /** Volatile version of {@link #getDouble(Object, long)} */ 2011 @HotSpotIntrinsicCandidate 2012 public native double getDoubleVolatile(Object o, long offset); 2013 2014 /** Volatile version of {@link #putDouble(Object, long, double)} */ 2015 @HotSpotIntrinsicCandidate 2016 public native void putDoubleVolatile(Object o, long offset, double x); 2017 2018 2019 2020 /** Acquire version of {@link #getObjectVolatile(Object, long)} */ 2021 @HotSpotIntrinsicCandidate 2022 public final Object getObjectAcquire(Object o, long offset) { 2023 return getObjectVolatile(o, offset); 2024 } 2025 2026 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */ 2027 @HotSpotIntrinsicCandidate 2028 public final boolean getBooleanAcquire(Object o, long offset) { 2029 return getBooleanVolatile(o, offset); 2030 } 2031 2032 /** Acquire version of {@link #getByteVolatile(Object, long)} */ 2033 @HotSpotIntrinsicCandidate 2034 public final byte getByteAcquire(Object o, long offset) { 2035 return getByteVolatile(o, offset); 2036 } 2037 2038 /** Acquire version of {@link #getShortVolatile(Object, long)} */ 2039 @HotSpotIntrinsicCandidate 2040 public final short getShortAcquire(Object o, long offset) { 2041 return getShortVolatile(o, offset); 2042 } 2043 2044 /** Acquire version of {@link #getCharVolatile(Object, long)} */ 2045 @HotSpotIntrinsicCandidate 2046 public final char getCharAcquire(Object o, long offset) { 2047 return getCharVolatile(o, offset); 2048 } 2049 2050 /** Acquire version of {@link #getIntVolatile(Object, long)} */ 2051 @HotSpotIntrinsicCandidate 2052 public final int getIntAcquire(Object o, long offset) { 2053 return getIntVolatile(o, offset); 2054 } 2055 2056 /** Acquire version of {@link #getFloatVolatile(Object, long)} */ 2057 @HotSpotIntrinsicCandidate 2058 public final float getFloatAcquire(Object o, long offset) { 2059 return getFloatVolatile(o, offset); 2060 } 2061 2062 /** Acquire version of {@link #getLongVolatile(Object, long)} */ 2063 @HotSpotIntrinsicCandidate 2064 public final long getLongAcquire(Object o, long offset) { 2065 return getLongVolatile(o, offset); 2066 } 2067 2068 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */ 2069 @HotSpotIntrinsicCandidate 2070 public final double getDoubleAcquire(Object o, long offset) { 2071 return getDoubleVolatile(o, offset); 2072 } 2073 2074 /* 2075 * Versions of {@link #putObjectVolatile(Object, long, Object)} 2076 * that do not guarantee immediate visibility of the store to 2077 * other threads. This method is generally only useful if the 2078 * underlying field is a Java volatile (or if an array cell, one 2079 * that is otherwise only accessed using volatile accesses). 2080 * 2081 * Corresponds to C11 atomic_store_explicit(..., memory_order_release). 2082 */ 2083 2084 /** Release version of {@link #putObjectVolatile(Object, long, Object)} */ 2085 @HotSpotIntrinsicCandidate 2086 public final void putObjectRelease(Object o, long offset, Object x) { 2087 putObjectVolatile(o, offset, x); 2088 } 2089 2090 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */ 2091 @HotSpotIntrinsicCandidate 2092 public final void putBooleanRelease(Object o, long offset, boolean x) { 2093 putBooleanVolatile(o, offset, x); 2094 } 2095 2096 /** Release version of {@link #putByteVolatile(Object, long, byte)} */ 2097 @HotSpotIntrinsicCandidate 2098 public final void putByteRelease(Object o, long offset, byte x) { 2099 putByteVolatile(o, offset, x); 2100 } 2101 2102 /** Release version of {@link #putShortVolatile(Object, long, short)} */ 2103 @HotSpotIntrinsicCandidate 2104 public final void putShortRelease(Object o, long offset, short x) { 2105 putShortVolatile(o, offset, x); 2106 } 2107 2108 /** Release version of {@link #putCharVolatile(Object, long, char)} */ 2109 @HotSpotIntrinsicCandidate 2110 public final void putCharRelease(Object o, long offset, char x) { 2111 putCharVolatile(o, offset, x); 2112 } 2113 2114 /** Release version of {@link #putIntVolatile(Object, long, int)} */ 2115 @HotSpotIntrinsicCandidate 2116 public final void putIntRelease(Object o, long offset, int x) { 2117 putIntVolatile(o, offset, x); 2118 } 2119 2120 /** Release version of {@link #putFloatVolatile(Object, long, float)} */ 2121 @HotSpotIntrinsicCandidate 2122 public final void putFloatRelease(Object o, long offset, float x) { 2123 putFloatVolatile(o, offset, x); 2124 } 2125 2126 /** Release version of {@link #putLongVolatile(Object, long, long)} */ 2127 @HotSpotIntrinsicCandidate 2128 public final void putLongRelease(Object o, long offset, long x) { 2129 putLongVolatile(o, offset, x); 2130 } 2131 2132 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */ 2133 @HotSpotIntrinsicCandidate 2134 public final void putDoubleRelease(Object o, long offset, double x) { 2135 putDoubleVolatile(o, offset, x); 2136 } 2137 2138 // ------------------------------ Opaque -------------------------------------- 2139 2140 /** Opaque version of {@link #getObjectVolatile(Object, long)} */ 2141 @HotSpotIntrinsicCandidate 2142 public final Object getObjectOpaque(Object o, long offset) { 2143 return getObjectVolatile(o, offset); 2144 } 2145 2146 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */ 2147 @HotSpotIntrinsicCandidate 2148 public final boolean getBooleanOpaque(Object o, long offset) { 2149 return getBooleanVolatile(o, offset); 2150 } 2151 2152 /** Opaque version of {@link #getByteVolatile(Object, long)} */ 2153 @HotSpotIntrinsicCandidate 2154 public final byte getByteOpaque(Object o, long offset) { 2155 return getByteVolatile(o, offset); 2156 } 2157 2158 /** Opaque version of {@link #getShortVolatile(Object, long)} */ 2159 @HotSpotIntrinsicCandidate 2160 public final short getShortOpaque(Object o, long offset) { 2161 return getShortVolatile(o, offset); 2162 } 2163 2164 /** Opaque version of {@link #getCharVolatile(Object, long)} */ 2165 @HotSpotIntrinsicCandidate 2166 public final char getCharOpaque(Object o, long offset) { 2167 return getCharVolatile(o, offset); 2168 } 2169 2170 /** Opaque version of {@link #getIntVolatile(Object, long)} */ 2171 @HotSpotIntrinsicCandidate 2172 public final int getIntOpaque(Object o, long offset) { 2173 return getIntVolatile(o, offset); 2174 } 2175 2176 /** Opaque version of {@link #getFloatVolatile(Object, long)} */ 2177 @HotSpotIntrinsicCandidate 2178 public final float getFloatOpaque(Object o, long offset) { 2179 return getFloatVolatile(o, offset); 2180 } 2181 2182 /** Opaque version of {@link #getLongVolatile(Object, long)} */ 2183 @HotSpotIntrinsicCandidate 2184 public final long getLongOpaque(Object o, long offset) { 2185 return getLongVolatile(o, offset); 2186 } 2187 2188 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */ 2189 @HotSpotIntrinsicCandidate 2190 public final double getDoubleOpaque(Object o, long offset) { 2191 return getDoubleVolatile(o, offset); 2192 } 2193 2194 /** Opaque version of {@link #putObjectVolatile(Object, long, Object)} */ 2195 @HotSpotIntrinsicCandidate 2196 public final void putObjectOpaque(Object o, long offset, Object x) { 2197 putObjectVolatile(o, offset, x); 2198 } 2199 2200 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */ 2201 @HotSpotIntrinsicCandidate 2202 public final void putBooleanOpaque(Object o, long offset, boolean x) { 2203 putBooleanVolatile(o, offset, x); 2204 } 2205 2206 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */ 2207 @HotSpotIntrinsicCandidate 2208 public final void putByteOpaque(Object o, long offset, byte x) { 2209 putByteVolatile(o, offset, x); 2210 } 2211 2212 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */ 2213 @HotSpotIntrinsicCandidate 2214 public final void putShortOpaque(Object o, long offset, short x) { 2215 putShortVolatile(o, offset, x); 2216 } 2217 2218 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */ 2219 @HotSpotIntrinsicCandidate 2220 public final void putCharOpaque(Object o, long offset, char x) { 2221 putCharVolatile(o, offset, x); 2222 } 2223 2224 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */ 2225 @HotSpotIntrinsicCandidate 2226 public final void putIntOpaque(Object o, long offset, int x) { 2227 putIntVolatile(o, offset, x); 2228 } 2229 2230 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */ 2231 @HotSpotIntrinsicCandidate 2232 public final void putFloatOpaque(Object o, long offset, float x) { 2233 putFloatVolatile(o, offset, x); 2234 } 2235 2236 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */ 2237 @HotSpotIntrinsicCandidate 2238 public final void putLongOpaque(Object o, long offset, long x) { 2239 putLongVolatile(o, offset, x); 2240 } 2241 2242 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */ 2243 @HotSpotIntrinsicCandidate 2244 public final void putDoubleOpaque(Object o, long offset, double x) { 2245 putDoubleVolatile(o, offset, x); 2246 } 2247 2248 /** 2249 * Unblocks the given thread blocked on {@code park}, or, if it is 2250 * not blocked, causes the subsequent call to {@code park} not to 2251 * block. Note: this operation is "unsafe" solely because the 2252 * caller must somehow ensure that the thread has not been 2253 * destroyed. Nothing special is usually required to ensure this 2254 * when called from Java (in which there will ordinarily be a live 2255 * reference to the thread) but this is not nearly-automatically 2256 * so when calling from native code. 2257 * 2258 * @param thread the thread to unpark. 2259 */ 2260 @HotSpotIntrinsicCandidate 2261 public native void unpark(Object thread); 2262 2263 /** 2264 * Blocks current thread, returning when a balancing 2265 * {@code unpark} occurs, or a balancing {@code unpark} has 2266 * already occurred, or the thread is interrupted, or, if not 2267 * absolute and time is not zero, the given time nanoseconds have 2268 * elapsed, or if absolute, the given deadline in milliseconds 2269 * since Epoch has passed, or spuriously (i.e., returning for no 2270 * "reason"). Note: This operation is in the Unsafe class only 2271 * because {@code unpark} is, so it would be strange to place it 2272 * elsewhere. 2273 */ 2274 @HotSpotIntrinsicCandidate 2275 public native void park(boolean isAbsolute, long time); 2276 2277 /** 2278 * Gets the load average in the system run queue assigned 2279 * to the available processors averaged over various periods of time. 2280 * This method retrieves the given {@code nelem} samples and 2281 * assigns to the elements of the given {@code loadavg} array. 2282 * The system imposes a maximum of 3 samples, representing 2283 * averages over the last 1, 5, and 15 minutes, respectively. 2284 * 2285 * @param loadavg an array of double of size nelems 2286 * @param nelems the number of samples to be retrieved and 2287 * must be 1 to 3. 2288 * 2289 * @return the number of samples actually retrieved; or -1 2290 * if the load average is unobtainable. 2291 */ 2292 public int getLoadAverage(double[] loadavg, int nelems) { 2293 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) { 2294 throw new ArrayIndexOutOfBoundsException(); 2295 } 2296 2297 return getLoadAverage0(loadavg, nelems); 2298 } 2299 2300 // The following contain CAS-based Java implementations used on 2301 // platforms not supporting native instructions 2302 2303 /** 2304 * Atomically adds the given value to the current value of a field 2305 * or array element within the given object {@code o} 2306 * at the given {@code offset}. 2307 * 2308 * @param o object/array to update the field/element in 2309 * @param offset field/element offset 2310 * @param delta the value to add 2311 * @return the previous value 2312 * @since 1.8 2313 */ 2314 @HotSpotIntrinsicCandidate 2315 public final int getAndAddInt(Object o, long offset, int delta) { 2316 int v; 2317 do { 2318 v = getIntVolatile(o, offset); 2319 } while (!weakCompareAndSetInt(o, offset, v, v + delta)); 2320 return v; 2321 } 2322 2323 @ForceInline 2324 public final int getAndAddIntRelease(Object o, long offset, int delta) { 2325 int v; 2326 do { 2327 v = getInt(o, offset); 2328 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta)); 2329 return v; 2330 } 2331 2332 @ForceInline 2333 public final int getAndAddIntAcquire(Object o, long offset, int delta) { 2334 int v; 2335 do { 2336 v = getIntAcquire(o, offset); 2337 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta)); 2338 return v; 2339 } 2340 2341 /** 2342 * Atomically adds the given value to the current value of a field 2343 * or array element within the given object {@code o} 2344 * at the given {@code offset}. 2345 * 2346 * @param o object/array to update the field/element in 2347 * @param offset field/element offset 2348 * @param delta the value to add 2349 * @return the previous value 2350 * @since 1.8 2351 */ 2352 @HotSpotIntrinsicCandidate 2353 public final long getAndAddLong(Object o, long offset, long delta) { 2354 long v; 2355 do { 2356 v = getLongVolatile(o, offset); 2357 } while (!weakCompareAndSetLong(o, offset, v, v + delta)); 2358 return v; 2359 } 2360 2361 @ForceInline 2362 public final long getAndAddLongRelease(Object o, long offset, long delta) { 2363 long v; 2364 do { 2365 v = getLong(o, offset); 2366 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta)); 2367 return v; 2368 } 2369 2370 @ForceInline 2371 public final long getAndAddLongAcquire(Object o, long offset, long delta) { 2372 long v; 2373 do { 2374 v = getLongAcquire(o, offset); 2375 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta)); 2376 return v; 2377 } 2378 2379 @HotSpotIntrinsicCandidate 2380 public final byte getAndAddByte(Object o, long offset, byte delta) { 2381 byte v; 2382 do { 2383 v = getByteVolatile(o, offset); 2384 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta))); 2385 return v; 2386 } 2387 2388 @ForceInline 2389 public final byte getAndAddByteRelease(Object o, long offset, byte delta) { 2390 byte v; 2391 do { 2392 v = getByte(o, offset); 2393 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta))); 2394 return v; 2395 } 2396 2397 @ForceInline 2398 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) { 2399 byte v; 2400 do { 2401 v = getByteAcquire(o, offset); 2402 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta))); 2403 return v; 2404 } 2405 2406 @HotSpotIntrinsicCandidate 2407 public final short getAndAddShort(Object o, long offset, short delta) { 2408 short v; 2409 do { 2410 v = getShortVolatile(o, offset); 2411 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta))); 2412 return v; 2413 } 2414 2415 @ForceInline 2416 public final short getAndAddShortRelease(Object o, long offset, short delta) { 2417 short v; 2418 do { 2419 v = getShort(o, offset); 2420 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta))); 2421 return v; 2422 } 2423 2424 @ForceInline 2425 public final short getAndAddShortAcquire(Object o, long offset, short delta) { 2426 short v; 2427 do { 2428 v = getShortAcquire(o, offset); 2429 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta))); 2430 return v; 2431 } 2432 2433 @ForceInline 2434 public final char getAndAddChar(Object o, long offset, char delta) { 2435 return (char) getAndAddShort(o, offset, (short) delta); 2436 } 2437 2438 @ForceInline 2439 public final char getAndAddCharRelease(Object o, long offset, char delta) { 2440 return (char) getAndAddShortRelease(o, offset, (short) delta); 2441 } 2442 2443 @ForceInline 2444 public final char getAndAddCharAcquire(Object o, long offset, char delta) { 2445 return (char) getAndAddShortAcquire(o, offset, (short) delta); 2446 } 2447 2448 @ForceInline 2449 public final float getAndAddFloat(Object o, long offset, float delta) { 2450 int expectedBits; 2451 float v; 2452 do { 2453 // Load and CAS with the raw bits to avoid issues with NaNs and 2454 // possible bit conversion from signaling NaNs to quiet NaNs that 2455 // may result in the loop not terminating. 2456 expectedBits = getIntVolatile(o, offset); 2457 v = Float.intBitsToFloat(expectedBits); 2458 } while (!weakCompareAndSetInt(o, offset, 2459 expectedBits, Float.floatToRawIntBits(v + delta))); 2460 return v; 2461 } 2462 2463 @ForceInline 2464 public final float getAndAddFloatRelease(Object o, long offset, float delta) { 2465 int expectedBits; 2466 float v; 2467 do { 2468 // Load and CAS with the raw bits to avoid issues with NaNs and 2469 // possible bit conversion from signaling NaNs to quiet NaNs that 2470 // may result in the loop not terminating. 2471 expectedBits = getInt(o, offset); 2472 v = Float.intBitsToFloat(expectedBits); 2473 } while (!weakCompareAndSetIntRelease(o, offset, 2474 expectedBits, Float.floatToRawIntBits(v + delta))); 2475 return v; 2476 } 2477 2478 @ForceInline 2479 public final float getAndAddFloatAcquire(Object o, long offset, float delta) { 2480 int expectedBits; 2481 float v; 2482 do { 2483 // Load and CAS with the raw bits to avoid issues with NaNs and 2484 // possible bit conversion from signaling NaNs to quiet NaNs that 2485 // may result in the loop not terminating. 2486 expectedBits = getIntAcquire(o, offset); 2487 v = Float.intBitsToFloat(expectedBits); 2488 } while (!weakCompareAndSetIntAcquire(o, offset, 2489 expectedBits, Float.floatToRawIntBits(v + delta))); 2490 return v; 2491 } 2492 2493 @ForceInline 2494 public final double getAndAddDouble(Object o, long offset, double delta) { 2495 long expectedBits; 2496 double v; 2497 do { 2498 // Load and CAS with the raw bits to avoid issues with NaNs and 2499 // possible bit conversion from signaling NaNs to quiet NaNs that 2500 // may result in the loop not terminating. 2501 expectedBits = getLongVolatile(o, offset); 2502 v = Double.longBitsToDouble(expectedBits); 2503 } while (!weakCompareAndSetLong(o, offset, 2504 expectedBits, Double.doubleToRawLongBits(v + delta))); 2505 return v; 2506 } 2507 2508 @ForceInline 2509 public final double getAndAddDoubleRelease(Object o, long offset, double delta) { 2510 long expectedBits; 2511 double v; 2512 do { 2513 // Load and CAS with the raw bits to avoid issues with NaNs and 2514 // possible bit conversion from signaling NaNs to quiet NaNs that 2515 // may result in the loop not terminating. 2516 expectedBits = getLong(o, offset); 2517 v = Double.longBitsToDouble(expectedBits); 2518 } while (!weakCompareAndSetLongRelease(o, offset, 2519 expectedBits, Double.doubleToRawLongBits(v + delta))); 2520 return v; 2521 } 2522 2523 @ForceInline 2524 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) { 2525 long expectedBits; 2526 double v; 2527 do { 2528 // Load and CAS with the raw bits to avoid issues with NaNs and 2529 // possible bit conversion from signaling NaNs to quiet NaNs that 2530 // may result in the loop not terminating. 2531 expectedBits = getLongAcquire(o, offset); 2532 v = Double.longBitsToDouble(expectedBits); 2533 } while (!weakCompareAndSetLongAcquire(o, offset, 2534 expectedBits, Double.doubleToRawLongBits(v + delta))); 2535 return v; 2536 } 2537 2538 /** 2539 * Atomically exchanges the given value with the current value of 2540 * a field or array element within the given object {@code o} 2541 * at the given {@code offset}. 2542 * 2543 * @param o object/array to update the field/element in 2544 * @param offset field/element offset 2545 * @param newValue new value 2546 * @return the previous value 2547 * @since 1.8 2548 */ 2549 @HotSpotIntrinsicCandidate 2550 public final int getAndSetInt(Object o, long offset, int newValue) { 2551 int v; 2552 do { 2553 v = getIntVolatile(o, offset); 2554 } while (!weakCompareAndSetInt(o, offset, v, newValue)); 2555 return v; 2556 } 2557 2558 @ForceInline 2559 public final int getAndSetIntRelease(Object o, long offset, int newValue) { 2560 int v; 2561 do { 2562 v = getInt(o, offset); 2563 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue)); 2564 return v; 2565 } 2566 2567 @ForceInline 2568 public final int getAndSetIntAcquire(Object o, long offset, int newValue) { 2569 int v; 2570 do { 2571 v = getIntAcquire(o, offset); 2572 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue)); 2573 return v; 2574 } 2575 2576 /** 2577 * Atomically exchanges the given value with the current value of 2578 * a field or array element within the given object {@code o} 2579 * at the given {@code offset}. 2580 * 2581 * @param o object/array to update the field/element in 2582 * @param offset field/element offset 2583 * @param newValue new value 2584 * @return the previous value 2585 * @since 1.8 2586 */ 2587 @HotSpotIntrinsicCandidate 2588 public final long getAndSetLong(Object o, long offset, long newValue) { 2589 long v; 2590 do { 2591 v = getLongVolatile(o, offset); 2592 } while (!weakCompareAndSetLong(o, offset, v, newValue)); 2593 return v; 2594 } 2595 2596 @ForceInline 2597 public final long getAndSetLongRelease(Object o, long offset, long newValue) { 2598 long v; 2599 do { 2600 v = getLong(o, offset); 2601 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue)); 2602 return v; 2603 } 2604 2605 @ForceInline 2606 public final long getAndSetLongAcquire(Object o, long offset, long newValue) { 2607 long v; 2608 do { 2609 v = getLongAcquire(o, offset); 2610 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue)); 2611 return v; 2612 } 2613 2614 /** 2615 * Atomically exchanges the given reference value with the current 2616 * reference value of a field or array element within the given 2617 * object {@code o} at the given {@code offset}. 2618 * 2619 * @param o object/array to update the field/element in 2620 * @param offset field/element offset 2621 * @param newValue new value 2622 * @return the previous value 2623 * @since 1.8 2624 */ 2625 @HotSpotIntrinsicCandidate 2626 public final Object getAndSetObject(Object o, long offset, Object newValue) { 2627 Object v; 2628 do { 2629 v = getObjectVolatile(o, offset); 2630 } while (!weakCompareAndSetObject(o, offset, v, newValue)); 2631 return v; 2632 } 2633 2634 @ForceInline 2635 public final Object getAndSetObjectRelease(Object o, long offset, Object newValue) { 2636 Object v; 2637 do { 2638 v = getObject(o, offset); 2639 } while (!weakCompareAndSetObjectRelease(o, offset, v, newValue)); 2640 return v; 2641 } 2642 2643 @ForceInline 2644 public final Object getAndSetObjectAcquire(Object o, long offset, Object newValue) { 2645 Object v; 2646 do { 2647 v = getObjectAcquire(o, offset); 2648 } while (!weakCompareAndSetObjectAcquire(o, offset, v, newValue)); 2649 return v; 2650 } 2651 2652 @HotSpotIntrinsicCandidate 2653 public final byte getAndSetByte(Object o, long offset, byte newValue) { 2654 byte v; 2655 do { 2656 v = getByteVolatile(o, offset); 2657 } while (!weakCompareAndSetByte(o, offset, v, newValue)); 2658 return v; 2659 } 2660 2661 @ForceInline 2662 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) { 2663 byte v; 2664 do { 2665 v = getByte(o, offset); 2666 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue)); 2667 return v; 2668 } 2669 2670 @ForceInline 2671 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) { 2672 byte v; 2673 do { 2674 v = getByteAcquire(o, offset); 2675 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue)); 2676 return v; 2677 } 2678 2679 @ForceInline 2680 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) { 2681 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue))); 2682 } 2683 2684 @ForceInline 2685 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) { 2686 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue))); 2687 } 2688 2689 @ForceInline 2690 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) { 2691 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue))); 2692 } 2693 2694 @HotSpotIntrinsicCandidate 2695 public final short getAndSetShort(Object o, long offset, short newValue) { 2696 short v; 2697 do { 2698 v = getShortVolatile(o, offset); 2699 } while (!weakCompareAndSetShort(o, offset, v, newValue)); 2700 return v; 2701 } 2702 2703 @ForceInline 2704 public final short getAndSetShortRelease(Object o, long offset, short newValue) { 2705 short v; 2706 do { 2707 v = getShort(o, offset); 2708 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue)); 2709 return v; 2710 } 2711 2712 @ForceInline 2713 public final short getAndSetShortAcquire(Object o, long offset, short newValue) { 2714 short v; 2715 do { 2716 v = getShortAcquire(o, offset); 2717 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue)); 2718 return v; 2719 } 2720 2721 @ForceInline 2722 public final char getAndSetChar(Object o, long offset, char newValue) { 2723 return s2c(getAndSetShort(o, offset, c2s(newValue))); 2724 } 2725 2726 @ForceInline 2727 public final char getAndSetCharRelease(Object o, long offset, char newValue) { 2728 return s2c(getAndSetShortRelease(o, offset, c2s(newValue))); 2729 } 2730 2731 @ForceInline 2732 public final char getAndSetCharAcquire(Object o, long offset, char newValue) { 2733 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue))); 2734 } 2735 2736 @ForceInline 2737 public final float getAndSetFloat(Object o, long offset, float newValue) { 2738 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue)); 2739 return Float.intBitsToFloat(v); 2740 } 2741 2742 @ForceInline 2743 public final float getAndSetFloatRelease(Object o, long offset, float newValue) { 2744 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue)); 2745 return Float.intBitsToFloat(v); 2746 } 2747 2748 @ForceInline 2749 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) { 2750 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue)); 2751 return Float.intBitsToFloat(v); 2752 } 2753 2754 @ForceInline 2755 public final double getAndSetDouble(Object o, long offset, double newValue) { 2756 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue)); 2757 return Double.longBitsToDouble(v); 2758 } 2759 2760 @ForceInline 2761 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) { 2762 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue)); 2763 return Double.longBitsToDouble(v); 2764 } 2765 2766 @ForceInline 2767 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) { 2768 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue)); 2769 return Double.longBitsToDouble(v); 2770 } 2771 2772 2773 // The following contain CAS-based Java implementations used on 2774 // platforms not supporting native instructions 2775 2776 @ForceInline 2777 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) { 2778 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask))); 2779 } 2780 2781 @ForceInline 2782 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) { 2783 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask))); 2784 } 2785 2786 @ForceInline 2787 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) { 2788 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask))); 2789 } 2790 2791 @ForceInline 2792 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) { 2793 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask))); 2794 } 2795 2796 @ForceInline 2797 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) { 2798 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask))); 2799 } 2800 2801 @ForceInline 2802 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) { 2803 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask))); 2804 } 2805 2806 @ForceInline 2807 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) { 2808 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask))); 2809 } 2810 2811 @ForceInline 2812 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) { 2813 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask))); 2814 } 2815 2816 @ForceInline 2817 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) { 2818 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask))); 2819 } 2820 2821 2822 @ForceInline 2823 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) { 2824 byte current; 2825 do { 2826 current = getByteVolatile(o, offset); 2827 } while (!weakCompareAndSetByte(o, offset, 2828 current, (byte) (current | mask))); 2829 return current; 2830 } 2831 2832 @ForceInline 2833 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) { 2834 byte current; 2835 do { 2836 current = getByte(o, offset); 2837 } while (!weakCompareAndSetByteRelease(o, offset, 2838 current, (byte) (current | mask))); 2839 return current; 2840 } 2841 2842 @ForceInline 2843 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) { 2844 byte current; 2845 do { 2846 // Plain read, the value is a hint, the acquire CAS does the work 2847 current = getByte(o, offset); 2848 } while (!weakCompareAndSetByteAcquire(o, offset, 2849 current, (byte) (current | mask))); 2850 return current; 2851 } 2852 2853 @ForceInline 2854 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) { 2855 byte current; 2856 do { 2857 current = getByteVolatile(o, offset); 2858 } while (!weakCompareAndSetByte(o, offset, 2859 current, (byte) (current & mask))); 2860 return current; 2861 } 2862 2863 @ForceInline 2864 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) { 2865 byte current; 2866 do { 2867 current = getByte(o, offset); 2868 } while (!weakCompareAndSetByteRelease(o, offset, 2869 current, (byte) (current & mask))); 2870 return current; 2871 } 2872 2873 @ForceInline 2874 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) { 2875 byte current; 2876 do { 2877 // Plain read, the value is a hint, the acquire CAS does the work 2878 current = getByte(o, offset); 2879 } while (!weakCompareAndSetByteAcquire(o, offset, 2880 current, (byte) (current & mask))); 2881 return current; 2882 } 2883 2884 @ForceInline 2885 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) { 2886 byte current; 2887 do { 2888 current = getByteVolatile(o, offset); 2889 } while (!weakCompareAndSetByte(o, offset, 2890 current, (byte) (current ^ mask))); 2891 return current; 2892 } 2893 2894 @ForceInline 2895 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) { 2896 byte current; 2897 do { 2898 current = getByte(o, offset); 2899 } while (!weakCompareAndSetByteRelease(o, offset, 2900 current, (byte) (current ^ mask))); 2901 return current; 2902 } 2903 2904 @ForceInline 2905 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) { 2906 byte current; 2907 do { 2908 // Plain read, the value is a hint, the acquire CAS does the work 2909 current = getByte(o, offset); 2910 } while (!weakCompareAndSetByteAcquire(o, offset, 2911 current, (byte) (current ^ mask))); 2912 return current; 2913 } 2914 2915 2916 @ForceInline 2917 public final char getAndBitwiseOrChar(Object o, long offset, char mask) { 2918 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask))); 2919 } 2920 2921 @ForceInline 2922 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) { 2923 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask))); 2924 } 2925 2926 @ForceInline 2927 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) { 2928 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask))); 2929 } 2930 2931 @ForceInline 2932 public final char getAndBitwiseAndChar(Object o, long offset, char mask) { 2933 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask))); 2934 } 2935 2936 @ForceInline 2937 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) { 2938 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask))); 2939 } 2940 2941 @ForceInline 2942 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) { 2943 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask))); 2944 } 2945 2946 @ForceInline 2947 public final char getAndBitwiseXorChar(Object o, long offset, char mask) { 2948 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask))); 2949 } 2950 2951 @ForceInline 2952 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) { 2953 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask))); 2954 } 2955 2956 @ForceInline 2957 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) { 2958 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask))); 2959 } 2960 2961 2962 @ForceInline 2963 public final short getAndBitwiseOrShort(Object o, long offset, short mask) { 2964 short current; 2965 do { 2966 current = getShortVolatile(o, offset); 2967 } while (!weakCompareAndSetShort(o, offset, 2968 current, (short) (current | mask))); 2969 return current; 2970 } 2971 2972 @ForceInline 2973 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) { 2974 short current; 2975 do { 2976 current = getShort(o, offset); 2977 } while (!weakCompareAndSetShortRelease(o, offset, 2978 current, (short) (current | mask))); 2979 return current; 2980 } 2981 2982 @ForceInline 2983 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) { 2984 short current; 2985 do { 2986 // Plain read, the value is a hint, the acquire CAS does the work 2987 current = getShort(o, offset); 2988 } while (!weakCompareAndSetShortAcquire(o, offset, 2989 current, (short) (current | mask))); 2990 return current; 2991 } 2992 2993 @ForceInline 2994 public final short getAndBitwiseAndShort(Object o, long offset, short mask) { 2995 short current; 2996 do { 2997 current = getShortVolatile(o, offset); 2998 } while (!weakCompareAndSetShort(o, offset, 2999 current, (short) (current & mask))); 3000 return current; 3001 } 3002 3003 @ForceInline 3004 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) { 3005 short current; 3006 do { 3007 current = getShort(o, offset); 3008 } while (!weakCompareAndSetShortRelease(o, offset, 3009 current, (short) (current & mask))); 3010 return current; 3011 } 3012 3013 @ForceInline 3014 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) { 3015 short current; 3016 do { 3017 // Plain read, the value is a hint, the acquire CAS does the work 3018 current = getShort(o, offset); 3019 } while (!weakCompareAndSetShortAcquire(o, offset, 3020 current, (short) (current & mask))); 3021 return current; 3022 } 3023 3024 @ForceInline 3025 public final short getAndBitwiseXorShort(Object o, long offset, short mask) { 3026 short current; 3027 do { 3028 current = getShortVolatile(o, offset); 3029 } while (!weakCompareAndSetShort(o, offset, 3030 current, (short) (current ^ mask))); 3031 return current; 3032 } 3033 3034 @ForceInline 3035 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) { 3036 short current; 3037 do { 3038 current = getShort(o, offset); 3039 } while (!weakCompareAndSetShortRelease(o, offset, 3040 current, (short) (current ^ mask))); 3041 return current; 3042 } 3043 3044 @ForceInline 3045 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) { 3046 short current; 3047 do { 3048 // Plain read, the value is a hint, the acquire CAS does the work 3049 current = getShort(o, offset); 3050 } while (!weakCompareAndSetShortAcquire(o, offset, 3051 current, (short) (current ^ mask))); 3052 return current; 3053 } 3054 3055 3056 @ForceInline 3057 public final int getAndBitwiseOrInt(Object o, long offset, int mask) { 3058 int current; 3059 do { 3060 current = getIntVolatile(o, offset); 3061 } while (!weakCompareAndSetInt(o, offset, 3062 current, current | mask)); 3063 return current; 3064 } 3065 3066 @ForceInline 3067 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) { 3068 int current; 3069 do { 3070 current = getInt(o, offset); 3071 } while (!weakCompareAndSetIntRelease(o, offset, 3072 current, current | mask)); 3073 return current; 3074 } 3075 3076 @ForceInline 3077 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) { 3078 int current; 3079 do { 3080 // Plain read, the value is a hint, the acquire CAS does the work 3081 current = getInt(o, offset); 3082 } while (!weakCompareAndSetIntAcquire(o, offset, 3083 current, current | mask)); 3084 return current; 3085 } 3086 3087 /** 3088 * Atomically replaces the current value of a field or array element within 3089 * the given object with the result of bitwise AND between the current value 3090 * and mask. 3091 * 3092 * @param o object/array to update the field/element in 3093 * @param offset field/element offset 3094 * @param mask the mask value 3095 * @return the previous value 3096 * @since 1.9 3097 */ 3098 @ForceInline 3099 public final int getAndBitwiseAndInt(Object o, long offset, int mask) { 3100 int current; 3101 do { 3102 current = getIntVolatile(o, offset); 3103 } while (!weakCompareAndSetInt(o, offset, 3104 current, current & mask)); 3105 return current; 3106 } 3107 3108 @ForceInline 3109 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) { 3110 int current; 3111 do { 3112 current = getInt(o, offset); 3113 } while (!weakCompareAndSetIntRelease(o, offset, 3114 current, current & mask)); 3115 return current; 3116 } 3117 3118 @ForceInline 3119 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) { 3120 int current; 3121 do { 3122 // Plain read, the value is a hint, the acquire CAS does the work 3123 current = getInt(o, offset); 3124 } while (!weakCompareAndSetIntAcquire(o, offset, 3125 current, current & mask)); 3126 return current; 3127 } 3128 3129 @ForceInline 3130 public final int getAndBitwiseXorInt(Object o, long offset, int mask) { 3131 int current; 3132 do { 3133 current = getIntVolatile(o, offset); 3134 } while (!weakCompareAndSetInt(o, offset, 3135 current, current ^ mask)); 3136 return current; 3137 } 3138 3139 @ForceInline 3140 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) { 3141 int current; 3142 do { 3143 current = getInt(o, offset); 3144 } while (!weakCompareAndSetIntRelease(o, offset, 3145 current, current ^ mask)); 3146 return current; 3147 } 3148 3149 @ForceInline 3150 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) { 3151 int current; 3152 do { 3153 // Plain read, the value is a hint, the acquire CAS does the work 3154 current = getInt(o, offset); 3155 } while (!weakCompareAndSetIntAcquire(o, offset, 3156 current, current ^ mask)); 3157 return current; 3158 } 3159 3160 3161 @ForceInline 3162 public final long getAndBitwiseOrLong(Object o, long offset, long mask) { 3163 long current; 3164 do { 3165 current = getLongVolatile(o, offset); 3166 } while (!weakCompareAndSetLong(o, offset, 3167 current, current | mask)); 3168 return current; 3169 } 3170 3171 @ForceInline 3172 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) { 3173 long current; 3174 do { 3175 current = getLong(o, offset); 3176 } while (!weakCompareAndSetLongRelease(o, offset, 3177 current, current | mask)); 3178 return current; 3179 } 3180 3181 @ForceInline 3182 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) { 3183 long current; 3184 do { 3185 // Plain read, the value is a hint, the acquire CAS does the work 3186 current = getLong(o, offset); 3187 } while (!weakCompareAndSetLongAcquire(o, offset, 3188 current, current | mask)); 3189 return current; 3190 } 3191 3192 @ForceInline 3193 public final long getAndBitwiseAndLong(Object o, long offset, long mask) { 3194 long current; 3195 do { 3196 current = getLongVolatile(o, offset); 3197 } while (!weakCompareAndSetLong(o, offset, 3198 current, current & mask)); 3199 return current; 3200 } 3201 3202 @ForceInline 3203 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) { 3204 long current; 3205 do { 3206 current = getLong(o, offset); 3207 } while (!weakCompareAndSetLongRelease(o, offset, 3208 current, current & mask)); 3209 return current; 3210 } 3211 3212 @ForceInline 3213 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) { 3214 long current; 3215 do { 3216 // Plain read, the value is a hint, the acquire CAS does the work 3217 current = getLong(o, offset); 3218 } while (!weakCompareAndSetLongAcquire(o, offset, 3219 current, current & mask)); 3220 return current; 3221 } 3222 3223 @ForceInline 3224 public final long getAndBitwiseXorLong(Object o, long offset, long mask) { 3225 long current; 3226 do { 3227 current = getLongVolatile(o, offset); 3228 } while (!weakCompareAndSetLong(o, offset, 3229 current, current ^ mask)); 3230 return current; 3231 } 3232 3233 @ForceInline 3234 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) { 3235 long current; 3236 do { 3237 current = getLong(o, offset); 3238 } while (!weakCompareAndSetLongRelease(o, offset, 3239 current, current ^ mask)); 3240 return current; 3241 } 3242 3243 @ForceInline 3244 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) { 3245 long current; 3246 do { 3247 // Plain read, the value is a hint, the acquire CAS does the work 3248 current = getLong(o, offset); 3249 } while (!weakCompareAndSetLongAcquire(o, offset, 3250 current, current ^ mask)); 3251 return current; 3252 } 3253 3254 3255 3256 /** 3257 * Ensures that loads before the fence will not be reordered with loads and 3258 * stores after the fence; a "LoadLoad plus LoadStore barrier". 3259 * 3260 * Corresponds to C11 atomic_thread_fence(memory_order_acquire) 3261 * (an "acquire fence"). 3262 * 3263 * A pure LoadLoad fence is not provided, since the addition of LoadStore 3264 * is almost always desired, and most current hardware instructions that 3265 * provide a LoadLoad barrier also provide a LoadStore barrier for free. 3266 * @since 1.8 3267 */ 3268 @HotSpotIntrinsicCandidate 3269 public native void loadFence(); 3270 3271 /** 3272 * Ensures that loads and stores before the fence will not be reordered with 3273 * stores after the fence; a "StoreStore plus LoadStore barrier". 3274 * 3275 * Corresponds to C11 atomic_thread_fence(memory_order_release) 3276 * (a "release fence"). 3277 * 3278 * A pure StoreStore fence is not provided, since the addition of LoadStore 3279 * is almost always desired, and most current hardware instructions that 3280 * provide a StoreStore barrier also provide a LoadStore barrier for free. 3281 * @since 1.8 3282 */ 3283 @HotSpotIntrinsicCandidate 3284 public native void storeFence(); 3285 3286 /** 3287 * Ensures that loads and stores before the fence will not be reordered 3288 * with loads and stores after the fence. Implies the effects of both 3289 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad 3290 * barrier. 3291 * 3292 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst). 3293 * @since 1.8 3294 */ 3295 @HotSpotIntrinsicCandidate 3296 public native void fullFence(); 3297 3298 /** 3299 * Ensures that loads before the fence will not be reordered with 3300 * loads after the fence. 3301 */ 3302 public final void loadLoadFence() { 3303 loadFence(); 3304 } 3305 3306 /** 3307 * Ensures that stores before the fence will not be reordered with 3308 * stores after the fence. 3309 */ 3310 public final void storeStoreFence() { 3311 storeFence(); 3312 } 3313 3314 3315 /** 3316 * Throws IllegalAccessError; for use by the VM for access control 3317 * error support. 3318 * @since 1.8 3319 */ 3320 private static void throwIllegalAccessError() { 3321 throw new IllegalAccessError(); 3322 } 3323 3324 /** 3325 * @return Returns true if the native byte ordering of this 3326 * platform is big-endian, false if it is little-endian. 3327 */ 3328 public final boolean isBigEndian() { return BE; } 3329 3330 /** 3331 * @return Returns true if this platform is capable of performing 3332 * accesses at addresses which are not aligned for the type of the 3333 * primitive type being accessed, false otherwise. 3334 */ 3335 public final boolean unalignedAccess() { return unalignedAccess; } 3336 3337 /** 3338 * Fetches a value at some byte offset into a given Java object. 3339 * More specifically, fetches a value within the given object 3340 * <code>o</code> at the given offset, or (if <code>o</code> is 3341 * null) from the memory address whose numerical value is the 3342 * given offset. <p> 3343 * 3344 * The specification of this method is the same as {@link 3345 * #getLong(Object, long)} except that the offset does not need to 3346 * have been obtained from {@link #objectFieldOffset} on the 3347 * {@link java.lang.reflect.Field} of some Java field. The value 3348 * in memory is raw data, and need not correspond to any Java 3349 * variable. Unless <code>o</code> is null, the value accessed 3350 * must be entirely within the allocated object. The endianness 3351 * of the value in memory is the endianness of the native platform. 3352 * 3353 * <p> The read will be atomic with respect to the largest power 3354 * of two that divides the GCD of the offset and the storage size. 3355 * For example, getLongUnaligned will make atomic reads of 2-, 4-, 3356 * or 8-byte storage units if the offset is zero mod 2, 4, or 8, 3357 * respectively. There are no other guarantees of atomicity. 3358 * <p> 3359 * 8-byte atomicity is only guaranteed on platforms on which 3360 * support atomic accesses to longs. 3361 * 3362 * @param o Java heap object in which the value resides, if any, else 3363 * null 3364 * @param offset The offset in bytes from the start of the object 3365 * @return the value fetched from the indicated object 3366 * @throws RuntimeException No defined exceptions are thrown, not even 3367 * {@link NullPointerException} 3368 * @since 9 3369 */ 3370 @HotSpotIntrinsicCandidate 3371 public final long getLongUnaligned(Object o, long offset) { 3372 if ((offset & 7) == 0) { 3373 return getLong(o, offset); 3374 } else if ((offset & 3) == 0) { 3375 return makeLong(getInt(o, offset), 3376 getInt(o, offset + 4)); 3377 } else if ((offset & 1) == 0) { 3378 return makeLong(getShort(o, offset), 3379 getShort(o, offset + 2), 3380 getShort(o, offset + 4), 3381 getShort(o, offset + 6)); 3382 } else { 3383 return makeLong(getByte(o, offset), 3384 getByte(o, offset + 1), 3385 getByte(o, offset + 2), 3386 getByte(o, offset + 3), 3387 getByte(o, offset + 4), 3388 getByte(o, offset + 5), 3389 getByte(o, offset + 6), 3390 getByte(o, offset + 7)); 3391 } 3392 } 3393 /** 3394 * As {@link #getLongUnaligned(Object, long)} but with an 3395 * additional argument which specifies the endianness of the value 3396 * as stored in memory. 3397 * 3398 * @param o Java heap object in which the variable resides 3399 * @param offset The offset in bytes from the start of the object 3400 * @param bigEndian The endianness of the value 3401 * @return the value fetched from the indicated object 3402 * @since 9 3403 */ 3404 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) { 3405 return convEndian(bigEndian, getLongUnaligned(o, offset)); 3406 } 3407 3408 /** @see #getLongUnaligned(Object, long) */ 3409 @HotSpotIntrinsicCandidate 3410 public final int getIntUnaligned(Object o, long offset) { 3411 if ((offset & 3) == 0) { 3412 return getInt(o, offset); 3413 } else if ((offset & 1) == 0) { 3414 return makeInt(getShort(o, offset), 3415 getShort(o, offset + 2)); 3416 } else { 3417 return makeInt(getByte(o, offset), 3418 getByte(o, offset + 1), 3419 getByte(o, offset + 2), 3420 getByte(o, offset + 3)); 3421 } 3422 } 3423 /** @see #getLongUnaligned(Object, long, boolean) */ 3424 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) { 3425 return convEndian(bigEndian, getIntUnaligned(o, offset)); 3426 } 3427 3428 /** @see #getLongUnaligned(Object, long) */ 3429 @HotSpotIntrinsicCandidate 3430 public final short getShortUnaligned(Object o, long offset) { 3431 if ((offset & 1) == 0) { 3432 return getShort(o, offset); 3433 } else { 3434 return makeShort(getByte(o, offset), 3435 getByte(o, offset + 1)); 3436 } 3437 } 3438 /** @see #getLongUnaligned(Object, long, boolean) */ 3439 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) { 3440 return convEndian(bigEndian, getShortUnaligned(o, offset)); 3441 } 3442 3443 /** @see #getLongUnaligned(Object, long) */ 3444 @HotSpotIntrinsicCandidate 3445 public final char getCharUnaligned(Object o, long offset) { 3446 if ((offset & 1) == 0) { 3447 return getChar(o, offset); 3448 } else { 3449 return (char)makeShort(getByte(o, offset), 3450 getByte(o, offset + 1)); 3451 } 3452 } 3453 3454 /** @see #getLongUnaligned(Object, long, boolean) */ 3455 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) { 3456 return convEndian(bigEndian, getCharUnaligned(o, offset)); 3457 } 3458 3459 /** 3460 * Stores a value at some byte offset into a given Java object. 3461 * <p> 3462 * The specification of this method is the same as {@link 3463 * #getLong(Object, long)} except that the offset does not need to 3464 * have been obtained from {@link #objectFieldOffset} on the 3465 * {@link java.lang.reflect.Field} of some Java field. The value 3466 * in memory is raw data, and need not correspond to any Java 3467 * variable. The endianness of the value in memory is the 3468 * endianness of the native platform. 3469 * <p> 3470 * The write will be atomic with respect to the largest power of 3471 * two that divides the GCD of the offset and the storage size. 3472 * For example, putLongUnaligned will make atomic writes of 2-, 4-, 3473 * or 8-byte storage units if the offset is zero mod 2, 4, or 8, 3474 * respectively. There are no other guarantees of atomicity. 3475 * <p> 3476 * 8-byte atomicity is only guaranteed on platforms on which 3477 * support atomic accesses to longs. 3478 * 3479 * @param o Java heap object in which the value resides, if any, else 3480 * null 3481 * @param offset The offset in bytes from the start of the object 3482 * @param x the value to store 3483 * @throws RuntimeException No defined exceptions are thrown, not even 3484 * {@link NullPointerException} 3485 * @since 9 3486 */ 3487 @HotSpotIntrinsicCandidate 3488 public final void putLongUnaligned(Object o, long offset, long x) { 3489 if ((offset & 7) == 0) { 3490 putLong(o, offset, x); 3491 } else if ((offset & 3) == 0) { 3492 putLongParts(o, offset, 3493 (int)(x >> 0), 3494 (int)(x >>> 32)); 3495 } else if ((offset & 1) == 0) { 3496 putLongParts(o, offset, 3497 (short)(x >>> 0), 3498 (short)(x >>> 16), 3499 (short)(x >>> 32), 3500 (short)(x >>> 48)); 3501 } else { 3502 putLongParts(o, offset, 3503 (byte)(x >>> 0), 3504 (byte)(x >>> 8), 3505 (byte)(x >>> 16), 3506 (byte)(x >>> 24), 3507 (byte)(x >>> 32), 3508 (byte)(x >>> 40), 3509 (byte)(x >>> 48), 3510 (byte)(x >>> 56)); 3511 } 3512 } 3513 3514 /** 3515 * As {@link #putLongUnaligned(Object, long, long)} but with an additional 3516 * argument which specifies the endianness of the value as stored in memory. 3517 * @param o Java heap object in which the value resides 3518 * @param offset The offset in bytes from the start of the object 3519 * @param x the value to store 3520 * @param bigEndian The endianness of the value 3521 * @throws RuntimeException No defined exceptions are thrown, not even 3522 * {@link NullPointerException} 3523 * @since 9 3524 */ 3525 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) { 3526 putLongUnaligned(o, offset, convEndian(bigEndian, x)); 3527 } 3528 3529 /** @see #putLongUnaligned(Object, long, long) */ 3530 @HotSpotIntrinsicCandidate 3531 public final void putIntUnaligned(Object o, long offset, int x) { 3532 if ((offset & 3) == 0) { 3533 putInt(o, offset, x); 3534 } else if ((offset & 1) == 0) { 3535 putIntParts(o, offset, 3536 (short)(x >> 0), 3537 (short)(x >>> 16)); 3538 } else { 3539 putIntParts(o, offset, 3540 (byte)(x >>> 0), 3541 (byte)(x >>> 8), 3542 (byte)(x >>> 16), 3543 (byte)(x >>> 24)); 3544 } 3545 } 3546 /** @see #putLongUnaligned(Object, long, long, boolean) */ 3547 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) { 3548 putIntUnaligned(o, offset, convEndian(bigEndian, x)); 3549 } 3550 3551 /** @see #putLongUnaligned(Object, long, long) */ 3552 @HotSpotIntrinsicCandidate 3553 public final void putShortUnaligned(Object o, long offset, short x) { 3554 if ((offset & 1) == 0) { 3555 putShort(o, offset, x); 3556 } else { 3557 putShortParts(o, offset, 3558 (byte)(x >>> 0), 3559 (byte)(x >>> 8)); 3560 } 3561 } 3562 /** @see #putLongUnaligned(Object, long, long, boolean) */ 3563 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) { 3564 putShortUnaligned(o, offset, convEndian(bigEndian, x)); 3565 } 3566 3567 /** @see #putLongUnaligned(Object, long, long) */ 3568 @HotSpotIntrinsicCandidate 3569 public final void putCharUnaligned(Object o, long offset, char x) { 3570 putShortUnaligned(o, offset, (short)x); 3571 } 3572 /** @see #putLongUnaligned(Object, long, long, boolean) */ 3573 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) { 3574 putCharUnaligned(o, offset, convEndian(bigEndian, x)); 3575 } 3576 3577 // JVM interface methods 3578 // BE is true iff the native endianness of this platform is big. 3579 private static final boolean BE = theUnsafe.isBigEndian0(); 3580 3581 // unalignedAccess is true iff this platform can perform unaligned accesses. 3582 private static final boolean unalignedAccess = theUnsafe.unalignedAccess0(); 3583 3584 private static int pickPos(int top, int pos) { return BE ? top - pos : pos; } 3585 3586 // These methods construct integers from bytes. The byte ordering 3587 // is the native endianness of this platform. 3588 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) { 3589 return ((toUnsignedLong(i0) << pickPos(56, 0)) 3590 | (toUnsignedLong(i1) << pickPos(56, 8)) 3591 | (toUnsignedLong(i2) << pickPos(56, 16)) 3592 | (toUnsignedLong(i3) << pickPos(56, 24)) 3593 | (toUnsignedLong(i4) << pickPos(56, 32)) 3594 | (toUnsignedLong(i5) << pickPos(56, 40)) 3595 | (toUnsignedLong(i6) << pickPos(56, 48)) 3596 | (toUnsignedLong(i7) << pickPos(56, 56))); 3597 } 3598 private static long makeLong(short i0, short i1, short i2, short i3) { 3599 return ((toUnsignedLong(i0) << pickPos(48, 0)) 3600 | (toUnsignedLong(i1) << pickPos(48, 16)) 3601 | (toUnsignedLong(i2) << pickPos(48, 32)) 3602 | (toUnsignedLong(i3) << pickPos(48, 48))); 3603 } 3604 private static long makeLong(int i0, int i1) { 3605 return (toUnsignedLong(i0) << pickPos(32, 0)) 3606 | (toUnsignedLong(i1) << pickPos(32, 32)); 3607 } 3608 private static int makeInt(short i0, short i1) { 3609 return (toUnsignedInt(i0) << pickPos(16, 0)) 3610 | (toUnsignedInt(i1) << pickPos(16, 16)); 3611 } 3612 private static int makeInt(byte i0, byte i1, byte i2, byte i3) { 3613 return ((toUnsignedInt(i0) << pickPos(24, 0)) 3614 | (toUnsignedInt(i1) << pickPos(24, 8)) 3615 | (toUnsignedInt(i2) << pickPos(24, 16)) 3616 | (toUnsignedInt(i3) << pickPos(24, 24))); 3617 } 3618 private static short makeShort(byte i0, byte i1) { 3619 return (short)((toUnsignedInt(i0) << pickPos(8, 0)) 3620 | (toUnsignedInt(i1) << pickPos(8, 8))); 3621 } 3622 3623 private static byte pick(byte le, byte be) { return BE ? be : le; } 3624 private static short pick(short le, short be) { return BE ? be : le; } 3625 private static int pick(int le, int be) { return BE ? be : le; } 3626 3627 // These methods write integers to memory from smaller parts 3628 // provided by their caller. The ordering in which these parts 3629 // are written is the native endianness of this platform. 3630 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) { 3631 putByte(o, offset + 0, pick(i0, i7)); 3632 putByte(o, offset + 1, pick(i1, i6)); 3633 putByte(o, offset + 2, pick(i2, i5)); 3634 putByte(o, offset + 3, pick(i3, i4)); 3635 putByte(o, offset + 4, pick(i4, i3)); 3636 putByte(o, offset + 5, pick(i5, i2)); 3637 putByte(o, offset + 6, pick(i6, i1)); 3638 putByte(o, offset + 7, pick(i7, i0)); 3639 } 3640 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) { 3641 putShort(o, offset + 0, pick(i0, i3)); 3642 putShort(o, offset + 2, pick(i1, i2)); 3643 putShort(o, offset + 4, pick(i2, i1)); 3644 putShort(o, offset + 6, pick(i3, i0)); 3645 } 3646 private void putLongParts(Object o, long offset, int i0, int i1) { 3647 putInt(o, offset + 0, pick(i0, i1)); 3648 putInt(o, offset + 4, pick(i1, i0)); 3649 } 3650 private void putIntParts(Object o, long offset, short i0, short i1) { 3651 putShort(o, offset + 0, pick(i0, i1)); 3652 putShort(o, offset + 2, pick(i1, i0)); 3653 } 3654 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) { 3655 putByte(o, offset + 0, pick(i0, i3)); 3656 putByte(o, offset + 1, pick(i1, i2)); 3657 putByte(o, offset + 2, pick(i2, i1)); 3658 putByte(o, offset + 3, pick(i3, i0)); 3659 } 3660 private void putShortParts(Object o, long offset, byte i0, byte i1) { 3661 putByte(o, offset + 0, pick(i0, i1)); 3662 putByte(o, offset + 1, pick(i1, i0)); 3663 } 3664 3665 // Zero-extend an integer 3666 private static int toUnsignedInt(byte n) { return n & 0xff; } 3667 private static int toUnsignedInt(short n) { return n & 0xffff; } 3668 private static long toUnsignedLong(byte n) { return n & 0xffl; } 3669 private static long toUnsignedLong(short n) { return n & 0xffffl; } 3670 private static long toUnsignedLong(int n) { return n & 0xffffffffl; } 3671 3672 // Maybe byte-reverse an integer 3673 private static char convEndian(boolean big, char n) { return big == BE ? n : Character.reverseBytes(n); } 3674 private static short convEndian(boolean big, short n) { return big == BE ? n : Short.reverseBytes(n) ; } 3675 private static int convEndian(boolean big, int n) { return big == BE ? n : Integer.reverseBytes(n) ; } 3676 private static long convEndian(boolean big, long n) { return big == BE ? n : Long.reverseBytes(n) ; } 3677 3678 3679 3680 private native long allocateMemory0(long bytes); 3681 private native long reallocateMemory0(long address, long bytes); 3682 private native void freeMemory0(long address); 3683 private native void setMemory0(Object o, long offset, long bytes, byte value); 3684 @HotSpotIntrinsicCandidate 3685 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes); 3686 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize); 3687 private native long objectFieldOffset0(Field f); 3688 private native long staticFieldOffset0(Field f); 3689 private native Object staticFieldBase0(Field f); 3690 private native boolean shouldBeInitialized0(Class<?> c); 3691 private native void ensureClassInitialized0(Class<?> c); 3692 private native int arrayBaseOffset0(Class<?> arrayClass); 3693 private native int arrayIndexScale0(Class<?> arrayClass); 3694 private native int addressSize0(); 3695 private native Class<?> defineAnonymousClass0(Class<?> hostClass, byte[] data, Object[] cpPatches); 3696 private native int getLoadAverage0(double[] loadavg, int nelems); 3697 private native boolean unalignedAccess0(); 3698 private native boolean isBigEndian0(); 3699} 3700