DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (5216dd412535)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=4 sw=4 et tw=99 ft=cpp:
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla SpiderMonkey JavaScript 1.9 code, released
 * June 30, 2010
 *
 * The Initial Developer of the Original Code is
 *   the Mozilla Corporation.
 *
 * Contributor(s):
 *   Luke Wagner <lw@mozilla.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef jsvalimpl_h__
#define jsvalimpl_h__
/*
 * JS value implementation details for operations on jsval and jsid.
 * Embeddings should not rely on any of the definitions in this file. For a
 * description of the value representation and the engine-internal C++ value
 * interface, js::Value, see jsvalue.h.
 */
#include "jsutil.h"

JS_BEGIN_EXTERN_C

/*
 * Try to get jsvals 64-bit aligned. We could almost assert that all values are
 * aligned, but MSVC and GCC occasionally break alignment.
 */
#ifdef __GNUC__
# define JSVAL_ALIGNMENT        __attribute__((aligned (8)))
#elif defined(_MSC_VER)
  /*
   * Structs can be aligned with MSVC, but not if they are used as parameters,
   * so we just don't try to align.
   */
# define JSVAL_ALIGNMENT
#elif defined(__SUNPRO_C) || defined(__SUNPRO_CC)
# define JSVAL_ALIGNMENT
#endif

#if JS_BITS_PER_WORD == 64
# define JSVAL_TAG_SHIFT 47
#endif

/*
 * We try to use enums so that printing a jsval_layout in the debugger shows
 * nice symbolic type tags, however we can only do this when we can force the
 * underlying type of the enum to be the desired size.
 */
#if defined(__cplusplus) && !defined(__SUNPRO_CC)

#if defined(_MSC_VER)
# define JS_ENUM_HEADER(id, type)              enum id : type
# define JS_ENUM_MEMBER(id, type, value)       id = (type)value,
# define JS_LAST_ENUM_MEMBER(id, type, value)  id = (type)value
# define JS_ENUM_FOOTER(id)
#else
# define JS_ENUM_HEADER(id, type)              enum id
# define JS_ENUM_MEMBER(id, type, value)       id = (type)value,
# define JS_LAST_ENUM_MEMBER(id, type, value)  id = (type)value
# define JS_ENUM_FOOTER(id)                    __attribute__((packed))
#endif

/* Remember to propagate changes to the C defines below. */
JS_ENUM_HEADER(JSValueType, uint8)
{
    JSVAL_TYPE_DOUBLE              = 0x00,
    JSVAL_TYPE_INT32               = 0x01,
    JSVAL_TYPE_UNDEFINED           = 0x02,
    JSVAL_TYPE_BOOLEAN             = 0x03,
    JSVAL_TYPE_MAGIC               = 0x04,
    JSVAL_TYPE_STRING              = 0x05,
    JSVAL_TYPE_NULL                = 0x06,
    JSVAL_TYPE_OBJECT              = 0x07,

    /* The below types never appear in a jsval; they are only used in tracing. */

    JSVAL_TYPE_NONFUNOBJ           = 0x57,
    JSVAL_TYPE_FUNOBJ              = 0x67,

    JSVAL_TYPE_STRORNULL           = 0x97,
    JSVAL_TYPE_OBJORNULL           = 0x98,

    JSVAL_TYPE_BOXED               = 0x99
} JS_ENUM_FOOTER(JSValueType);

JS_STATIC_ASSERT(sizeof(JSValueType) == 1);

#if JS_BITS_PER_WORD == 32

/* Remember to propagate changes to the C defines below. */
JS_ENUM_HEADER(JSValueTag, uint32)
{
    JSVAL_TAG_CLEAR                = 0xFFFF0000,
    JSVAL_TAG_INT32                = JSVAL_TAG_CLEAR | JSVAL_TYPE_INT32,
    JSVAL_TAG_UNDEFINED            = JSVAL_TAG_CLEAR | JSVAL_TYPE_UNDEFINED,
    JSVAL_TAG_STRING               = JSVAL_TAG_CLEAR | JSVAL_TYPE_STRING,
    JSVAL_TAG_BOOLEAN              = JSVAL_TAG_CLEAR | JSVAL_TYPE_BOOLEAN,
    JSVAL_TAG_MAGIC                = JSVAL_TAG_CLEAR | JSVAL_TYPE_MAGIC,
    JSVAL_TAG_NULL                 = JSVAL_TAG_CLEAR | JSVAL_TYPE_NULL,
    JSVAL_TAG_OBJECT               = JSVAL_TAG_CLEAR | JSVAL_TYPE_OBJECT
} JS_ENUM_FOOTER(JSValueTag);

JS_STATIC_ASSERT(sizeof(JSValueTag) == 4);

#elif JS_BITS_PER_WORD == 64

/* Remember to propagate changes to the C defines below. */
JS_ENUM_HEADER(JSValueTag, uint32)
{
    JSVAL_TAG_MAX_DOUBLE           = 0x1FFF0,
    JSVAL_TAG_INT32                = JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_INT32,
    JSVAL_TAG_UNDEFINED            = JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_UNDEFINED,
    JSVAL_TAG_STRING               = JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_STRING,
    JSVAL_TAG_BOOLEAN              = JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_BOOLEAN,
    JSVAL_TAG_MAGIC                = JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_MAGIC,
    JSVAL_TAG_NULL                 = JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_NULL,
    JSVAL_TAG_OBJECT               = JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_OBJECT
} JS_ENUM_FOOTER(JSValueTag);

JS_STATIC_ASSERT(sizeof(JSValueTag) == sizeof(uint32));

JS_ENUM_HEADER(JSValueShiftedTag, uint64)
{
    JSVAL_SHIFTED_TAG_MAX_DOUBLE   = ((((uint64)JSVAL_TAG_MAX_DOUBLE) << JSVAL_TAG_SHIFT) | 0xFFFFFFFF),
    JSVAL_SHIFTED_TAG_INT32        = (((uint64)JSVAL_TAG_INT32)      << JSVAL_TAG_SHIFT),
    JSVAL_SHIFTED_TAG_UNDEFINED    = (((uint64)JSVAL_TAG_UNDEFINED)  << JSVAL_TAG_SHIFT),
    JSVAL_SHIFTED_TAG_STRING       = (((uint64)JSVAL_TAG_STRING)     << JSVAL_TAG_SHIFT),
    JSVAL_SHIFTED_TAG_BOOLEAN      = (((uint64)JSVAL_TAG_BOOLEAN)    << JSVAL_TAG_SHIFT),
    JSVAL_SHIFTED_TAG_MAGIC        = (((uint64)JSVAL_TAG_MAGIC)      << JSVAL_TAG_SHIFT),
    JSVAL_SHIFTED_TAG_NULL         = (((uint64)JSVAL_TAG_NULL)       << JSVAL_TAG_SHIFT),
    JSVAL_SHIFTED_TAG_OBJECT       = (((uint64)JSVAL_TAG_OBJECT)     << JSVAL_TAG_SHIFT)
} JS_ENUM_FOOTER(JSValueShiftedTag);

JS_STATIC_ASSERT(sizeof(JSValueShiftedTag) == sizeof(uint64));

#endif

#else  /* defined(__cplusplus) */

typedef uint8 JSValueType;
#define JSVAL_TYPE_DOUBLE            ((uint8)0x00)
#define JSVAL_TYPE_INT32             ((uint8)0x01)
#define JSVAL_TYPE_UNDEFINED         ((uint8)0x02)
#define JSVAL_TYPE_BOOLEAN           ((uint8)0x03)
#define JSVAL_TYPE_MAGIC             ((uint8)0x04)
#define JSVAL_TYPE_STRING            ((uint8)0x05)
#define JSVAL_TYPE_NULL              ((uint8)0x06)
#define JSVAL_TYPE_OBJECT            ((uint8)0x07)
#define JSVAL_TYPE_NONFUNOBJ         ((uint8)0x57)
#define JSVAL_TYPE_FUNOBJ            ((uint8)0x67)
#define JSVAL_TYPE_STRORNULL         ((uint8)0x97)
#define JSVAL_TYPE_OBJORNULL         ((uint8)0x98)
#define JSVAL_TYPE_BOXED             ((uint8)0x99)
#define JSVAL_TYPE_UNINITIALIZED     ((uint8)0xcd)

#if JS_BITS_PER_WORD == 32

typedef uint32 JSValueTag;
#define JSVAL_TAG_CLEAR              ((uint32)(0xFFFF0000))
#define JSVAL_TAG_INT32              ((uint32)(JSVAL_TAG_CLEAR | JSVAL_TYPE_INT32))
#define JSVAL_TAG_UNDEFINED          ((uint32)(JSVAL_TAG_CLEAR | JSVAL_TYPE_UNDEFINED))
#define JSVAL_TAG_STRING             ((uint32)(JSVAL_TAG_CLEAR | JSVAL_TYPE_STRING))
#define JSVAL_TAG_BOOLEAN            ((uint32)(JSVAL_TAG_CLEAR | JSVAL_TYPE_BOOLEAN))
#define JSVAL_TAG_MAGIC              ((uint32)(JSVAL_TAG_CLEAR | JSVAL_TYPE_MAGIC))
#define JSVAL_TAG_NULL               ((uint32)(JSVAL_TAG_CLEAR | JSVAL_TYPE_NULL))
#define JSVAL_TAG_OBJECT             ((uint32)(JSVAL_TAG_CLEAR | JSVAL_TYPE_OBJECT))

#elif JS_BITS_PER_WORD == 64

typedef uint32 JSValueTag;
#define JSVAL_TAG_MAX_DOUBLE         ((uint32)(0x1FFF0))
#define JSVAL_TAG_INT32              (uint32)(JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_INT32)
#define JSVAL_TAG_UNDEFINED          (uint32)(JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_UNDEFINED)
#define JSVAL_TAG_STRING             (uint32)(JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_STRING)
#define JSVAL_TAG_BOOLEAN            (uint32)(JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_BOOLEAN)
#define JSVAL_TAG_MAGIC              (uint32)(JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_MAGIC)
#define JSVAL_TAG_NULL               (uint32)(JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_NULL)
#define JSVAL_TAG_OBJECT             (uint32)(JSVAL_TAG_MAX_DOUBLE | JSVAL_TYPE_OBJECT)

typedef uint64 JSValueShiftedTag;
#define JSVAL_SHIFTED_TAG_MAX_DOUBLE ((((uint64)JSVAL_TAG_MAX_DOUBLE) << JSVAL_TAG_SHIFT) | 0xFFFFFFFF)
#define JSVAL_SHIFTED_TAG_INT32      (((uint64)JSVAL_TAG_INT32)      << JSVAL_TAG_SHIFT)
#define JSVAL_SHIFTED_TAG_UNDEFINED  (((uint64)JSVAL_TAG_UNDEFINED)  << JSVAL_TAG_SHIFT)
#define JSVAL_SHIFTED_TAG_STRING     (((uint64)JSVAL_TAG_STRING)     << JSVAL_TAG_SHIFT)
#define JSVAL_SHIFTED_TAG_BOOLEAN    (((uint64)JSVAL_TAG_BOOLEAN)    << JSVAL_TAG_SHIFT)
#define JSVAL_SHIFTED_TAG_MAGIC      (((uint64)JSVAL_TAG_MAGIC)      << JSVAL_TAG_SHIFT)
#define JSVAL_SHIFTED_TAG_NULL       (((uint64)JSVAL_TAG_NULL)       << JSVAL_TAG_SHIFT)
#define JSVAL_SHIFTED_TAG_OBJECT     (((uint64)JSVAL_TAG_OBJECT)     << JSVAL_TAG_SHIFT)

#endif  /* JS_BITS_PER_WORD */
#endif  /* defined(__cplusplus) && !defined(__SUNPRO_CC) */

#define JSVAL_LOWER_INCL_TYPE_OF_OBJ_OR_NULL_SET        JSVAL_TYPE_NULL
#define JSVAL_UPPER_EXCL_TYPE_OF_PRIMITIVE_SET          JSVAL_TYPE_OBJECT
#define JSVAL_UPPER_INCL_TYPE_OF_NUMBER_SET             JSVAL_TYPE_INT32
#define JSVAL_LOWER_INCL_TYPE_OF_PTR_PAYLOAD_SET        JSVAL_TYPE_MAGIC
#define JSVAL_UPPER_INCL_TYPE_OF_VALUE_SET              JSVAL_TYPE_OBJECT
#define JSVAL_UPPER_INCL_TYPE_OF_BOXABLE_SET            JSVAL_TYPE_FUNOBJ

#if JS_BITS_PER_WORD == 32

#define JSVAL_TYPE_TO_TAG(type)      ((JSValueTag)(JSVAL_TAG_CLEAR | (type)))

#define JSVAL_LOWER_INCL_TAG_OF_OBJ_OR_NULL_SET         JSVAL_TAG_NULL
#define JSVAL_UPPER_EXCL_TAG_OF_PRIMITIVE_SET           JSVAL_TAG_OBJECT
#define JSVAL_UPPER_INCL_TAG_OF_NUMBER_SET              JSVAL_TAG_INT32
#define JSVAL_LOWER_INCL_TAG_OF_GCTHING_SET             JSVAL_TAG_STRING

#elif JS_BITS_PER_WORD == 64

#define JSVAL_PAYLOAD_MASK           0x00007FFFFFFFFFFFLL
#define JSVAL_TAG_MASK               0xFFFF800000000000LL
#define JSVAL_TYPE_TO_TAG(type)      ((JSValueTag)(JSVAL_TAG_MAX_DOUBLE | (type)))
#define JSVAL_TYPE_TO_SHIFTED_TAG(type) (((uint64)JSVAL_TYPE_TO_TAG(type)) << JSVAL_TAG_SHIFT)

#define JSVAL_LOWER_INCL_SHIFTED_TAG_OF_OBJ_OR_NULL_SET  JSVAL_SHIFTED_TAG_NULL
#define JSVAL_UPPER_EXCL_SHIFTED_TAG_OF_PRIMITIVE_SET    JSVAL_SHIFTED_TAG_OBJECT
#define JSVAL_UPPER_EXCL_SHIFTED_TAG_OF_NUMBER_SET       JSVAL_SHIFTED_TAG_UNDEFINED
#define JSVAL_LOWER_INCL_SHIFTED_TAG_OF_PTR_PAYLOAD_SET  JSVAL_SHIFTED_TAG_MAGIC
#define JSVAL_LOWER_INCL_SHIFTED_TAG_OF_GCTHING_SET      JSVAL_SHIFTED_TAG_STRING

#endif /* JS_BITS_PER_WORD */

typedef enum JSWhyMagic
{
    JS_ARRAY_HOLE,               /* a hole in a dense array */
    JS_ARGS_HOLE,                /* a hole in the args object's array */
    JS_NATIVE_ENUMERATE,         /* indicates that a custom enumerate hook forwarded
                                  * to js_Enumerate, which really means the object can be
                                  * enumerated like a native object. */
    JS_NO_ITER_VALUE,            /* there is not a pending iterator value */
    JS_GENERATOR_CLOSING,        /* exception value thrown when closing a generator */
    JS_NO_CONSTANT,              /* compiler sentinel value */
    JS_THIS_POISON,              /* used in debug builds to catch tracing errors */
    JS_ARG_POISON,               /* used in debug builds to catch tracing errors */
    JS_SERIALIZE_NO_NODE,        /* an empty subnode in the AST serializer */
    JS_GENERIC_MAGIC             /* for local use */
} JSWhyMagic;

typedef struct JSString     JSString;
typedef struct JSFlatString JSFlatString;
typedef struct JSObject     JSObject;

#if defined(IS_LITTLE_ENDIAN)
# if JS_BITS_PER_WORD == 32
typedef union jsval_layout
{
    uint64 asBits;
    struct {
        union {
            int32          i32;
            uint32         u32;
            JSBool         boo;
            JSString       *str;
            JSObject       *obj;
            void           *ptr;
            JSWhyMagic     why;
            jsuword        word;
        } payload;
        JSValueTag tag;
    } s;
    double asDouble;
    void *asPtr;
} jsval_layout;
# elif JS_BITS_PER_WORD == 64
typedef union jsval_layout
{
    uint64 asBits;
#if (!defined(_WIN64) && defined(__cplusplus))
    /* MSVC does not pack these correctly :-( */
    struct {
        uint64             payload47 : 47;
        JSValueTag         tag : 17;
    } debugView;
#endif
    struct {
        union {
            int32          i32;
            uint32         u32;
            JSWhyMagic     why;
            jsuword        word;
        } payload;
    } s;
    double asDouble;
    void *asPtr;
} jsval_layout;
# endif  /* JS_BITS_PER_WORD */
#else   /* defined(IS_LITTLE_ENDIAN) */
# if JS_BITS_PER_WORD == 32
typedef union jsval_layout
{
    uint64 asBits;
    struct {
        JSValueTag tag;
        union {
            int32          i32;
            uint32         u32;
            JSBool         boo;
            JSString       *str;
            JSObject       *obj;
            void           *ptr;
            JSWhyMagic     why;
            jsuword        word;
        } payload;
    } s;
    double asDouble;
    void *asPtr;
} jsval_layout;
# elif JS_BITS_PER_WORD == 64
typedef union jsval_layout
{
    uint64 asBits;
    struct {
        JSValueTag         tag : 17;
        uint64             payload47 : 47;
    } debugView;
    struct {
        union {
            int32          i32;
            uint32         u32;
            JSWhyMagic     why;
        } payload;
    } s;
    double asDouble;
    void *asPtr;
} jsval_layout;
# endif /* JS_BITS_PER_WORD */
#endif  /* defined(IS_LITTLE_ENDIAN) */

#if JS_BITS_PER_WORD == 32

/*
 * N.B. GCC, in some but not all cases, chooses to emit signed comparison of
 * JSValueTag even though its underlying type has been forced to be uint32.
 * Thus, all comparisons should explicitly cast operands to uint32.
 */

#define BUILD_JSVAL(tag, payload) \
    ((((uint64)(uint32)(tag)) << 32) | (uint32)(payload))

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_DOUBLE_IMPL(jsval_layout l)
{
    return (uint32)l.s.tag <= (uint32)JSVAL_TAG_CLEAR;
}

static JS_ALWAYS_INLINE jsval_layout
DOUBLE_TO_JSVAL_IMPL(double d)
{
    jsval_layout l;
    l.asDouble = d;
    JS_ASSERT(JSVAL_IS_DOUBLE_IMPL(l));
    return l;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_INT32_IMPL(jsval_layout l)
{
    return l.s.tag == JSVAL_TAG_INT32;
}

static JS_ALWAYS_INLINE int32
JSVAL_TO_INT32_IMPL(jsval_layout l)
{
    return l.s.payload.i32;
}

static JS_ALWAYS_INLINE jsval_layout
INT32_TO_JSVAL_IMPL(int32 i)
{
    jsval_layout l;
    l.s.tag = JSVAL_TAG_INT32;
    l.s.payload.i32 = i;
    return l;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_NUMBER_IMPL(jsval_layout l)
{
    JSValueTag tag = l.s.tag;
    JS_ASSERT(tag != JSVAL_TAG_CLEAR);
    return (uint32)tag <= (uint32)JSVAL_UPPER_INCL_TAG_OF_NUMBER_SET;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_UNDEFINED_IMPL(jsval_layout l)
{
    return l.s.tag == JSVAL_TAG_UNDEFINED;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_STRING_IMPL(jsval_layout l)
{
    return l.s.tag == JSVAL_TAG_STRING;
}

static JS_ALWAYS_INLINE jsval_layout
STRING_TO_JSVAL_IMPL(JSString *str)
{
    jsval_layout l;
    JS_ASSERT(str);
    l.s.tag = JSVAL_TAG_STRING;
    l.s.payload.str = str;
    return l;
}

static JS_ALWAYS_INLINE JSString *
JSVAL_TO_STRING_IMPL(jsval_layout l)
{
    return l.s.payload.str;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_BOOLEAN_IMPL(jsval_layout l)
{
    return l.s.tag == JSVAL_TAG_BOOLEAN;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_TO_BOOLEAN_IMPL(jsval_layout l)
{
    return l.s.payload.boo;
}

static JS_ALWAYS_INLINE jsval_layout
BOOLEAN_TO_JSVAL_IMPL(JSBool b)
{
    jsval_layout l;
    l.s.tag = JSVAL_TAG_BOOLEAN;
    l.s.payload.boo = b;
    return l;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_MAGIC_IMPL(jsval_layout l)
{
    return l.s.tag == JSVAL_TAG_MAGIC;
}

static JS_ALWAYS_INLINE JSObject *
MAGIC_JSVAL_TO_OBJECT_OR_NULL_IMPL(jsval_layout l)
{
    JS_ASSERT(JSVAL_IS_MAGIC_IMPL(l));
    return l.s.payload.obj;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_OBJECT_IMPL(jsval_layout l)
{
    return l.s.tag == JSVAL_TAG_OBJECT;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_PRIMITIVE_IMPL(jsval_layout l)
{
    return (uint32)l.s.tag < (uint32)JSVAL_UPPER_EXCL_TAG_OF_PRIMITIVE_SET;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_OBJECT_OR_NULL_IMPL(jsval_layout l)
{
    JS_ASSERT((uint32)l.s.tag <= (uint32)JSVAL_TAG_OBJECT);
    return (uint32)l.s.tag >= (uint32)JSVAL_LOWER_INCL_TAG_OF_OBJ_OR_NULL_SET;
}

static JS_ALWAYS_INLINE JSObject *
JSVAL_TO_OBJECT_IMPL(jsval_layout l)
{
    return l.s.payload.obj;
}

static JS_ALWAYS_INLINE jsval_layout
OBJECT_TO_JSVAL_IMPL(JSObject *obj)
{
    jsval_layout l;
    JS_ASSERT(obj);
    l.s.tag = JSVAL_TAG_OBJECT;
    l.s.payload.obj = obj;
    return l;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_NULL_IMPL(jsval_layout l)
{
    return l.s.tag == JSVAL_TAG_NULL;
}

static JS_ALWAYS_INLINE jsval_layout
PRIVATE_PTR_TO_JSVAL_IMPL(void *ptr)
{
    jsval_layout l;
    JS_ASSERT(((uint32)ptr & 1) == 0);
    l.s.tag = (JSValueTag)0;
    l.s.payload.ptr = ptr;
    JS_ASSERT(JSVAL_IS_DOUBLE_IMPL(l));
    return l;
}

static JS_ALWAYS_INLINE void *
JSVAL_TO_PRIVATE_PTR_IMPL(jsval_layout l)
{
    return l.s.payload.ptr;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_GCTHING_IMPL(jsval_layout l)
{
    /* gcc sometimes generates signed < without explicit casts. */
    return (uint32)l.s.tag >= (uint32)JSVAL_LOWER_INCL_TAG_OF_GCTHING_SET;
}

static JS_ALWAYS_INLINE void *
JSVAL_TO_GCTHING_IMPL(jsval_layout l)
{
    return l.s.payload.ptr;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_TRACEABLE_IMPL(jsval_layout l)
{
    return l.s.tag == JSVAL_TAG_STRING || l.s.tag == JSVAL_TAG_OBJECT;
}

static JS_ALWAYS_INLINE uint32
JSVAL_TRACE_KIND_IMPL(jsval_layout l)
{
    return (uint32)(JSBool)JSVAL_IS_STRING_IMPL(l);
}

#elif JS_BITS_PER_WORD == 64

#define BUILD_JSVAL(tag, payload) \
    ((((uint64)(uint32)(tag)) << JSVAL_TAG_SHIFT) | (payload))

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_DOUBLE_IMPL(jsval_layout l)
{
    return l.asBits <= JSVAL_SHIFTED_TAG_MAX_DOUBLE;
}

static JS_ALWAYS_INLINE jsval_layout
DOUBLE_TO_JSVAL_IMPL(double d)
{
    jsval_layout l;
    l.asDouble = d;
    JS_ASSERT(l.asBits <= JSVAL_SHIFTED_TAG_MAX_DOUBLE);
    return l;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_INT32_IMPL(jsval_layout l)
{
    return (uint32)(l.asBits >> JSVAL_TAG_SHIFT) == JSVAL_TAG_INT32;
}

static JS_ALWAYS_INLINE int32
JSVAL_TO_INT32_IMPL(jsval_layout l)
{
    return (int32)l.asBits;
}

static JS_ALWAYS_INLINE jsval_layout
INT32_TO_JSVAL_IMPL(int32 i32)
{
    jsval_layout l;
    l.asBits = ((uint64)(uint32)i32) | JSVAL_SHIFTED_TAG_INT32;
    return l;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_NUMBER_IMPL(jsval_layout l)
{
    return l.asBits < JSVAL_UPPER_EXCL_SHIFTED_TAG_OF_NUMBER_SET;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_UNDEFINED_IMPL(jsval_layout l)
{
    return l.asBits == JSVAL_SHIFTED_TAG_UNDEFINED;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_STRING_IMPL(jsval_layout l)
{
    return (uint32)(l.asBits >> JSVAL_TAG_SHIFT) == JSVAL_TAG_STRING;
}

static JS_ALWAYS_INLINE jsval_layout
STRING_TO_JSVAL_IMPL(JSString *str)
{
    jsval_layout l;
    uint64 strBits = (uint64)str;
    JS_ASSERT(str);
    JS_ASSERT((strBits >> JSVAL_TAG_SHIFT) == 0);
    l.asBits = strBits | JSVAL_SHIFTED_TAG_STRING;
    return l;
}

static JS_ALWAYS_INLINE JSString *
JSVAL_TO_STRING_IMPL(jsval_layout l)
{
    return (JSString *)(l.asBits & JSVAL_PAYLOAD_MASK);
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_BOOLEAN_IMPL(jsval_layout l)
{
    return (uint32)(l.asBits >> JSVAL_TAG_SHIFT) == JSVAL_TAG_BOOLEAN;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_TO_BOOLEAN_IMPL(jsval_layout l)
{
    return (JSBool)l.asBits;
}

static JS_ALWAYS_INLINE jsval_layout
BOOLEAN_TO_JSVAL_IMPL(JSBool b)
{
    jsval_layout l;
    l.asBits = ((uint64)(uint32)b) | JSVAL_SHIFTED_TAG_BOOLEAN;
    return l;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_MAGIC_IMPL(jsval_layout l)
{
    return (l.asBits >> JSVAL_TAG_SHIFT) == JSVAL_TAG_MAGIC;
}

static JS_ALWAYS_INLINE JSObject *
MAGIC_JSVAL_TO_OBJECT_OR_NULL_IMPL(jsval_layout l)
{
    uint64 ptrBits = l.asBits & JSVAL_PAYLOAD_MASK;
    JS_ASSERT(JSVAL_IS_MAGIC_IMPL(l));
    JS_ASSERT((ptrBits >> JSVAL_TAG_SHIFT) == 0);
    return (JSObject *)ptrBits;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_PRIMITIVE_IMPL(jsval_layout l)
{
    return l.asBits < JSVAL_UPPER_EXCL_SHIFTED_TAG_OF_PRIMITIVE_SET;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_OBJECT_IMPL(jsval_layout l)
{
    JS_ASSERT((l.asBits >> JSVAL_TAG_SHIFT) <= JSVAL_SHIFTED_TAG_OBJECT);
    return l.asBits >= JSVAL_SHIFTED_TAG_OBJECT;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_OBJECT_OR_NULL_IMPL(jsval_layout l)
{
    JS_ASSERT((l.asBits >> JSVAL_TAG_SHIFT) <= JSVAL_TAG_OBJECT);
    return l.asBits >= JSVAL_LOWER_INCL_SHIFTED_TAG_OF_OBJ_OR_NULL_SET;
}

static JS_ALWAYS_INLINE JSObject *
JSVAL_TO_OBJECT_IMPL(jsval_layout l)
{
    uint64 ptrBits = l.asBits & JSVAL_PAYLOAD_MASK;
    JS_ASSERT((ptrBits & 0x7) == 0);
    return (JSObject *)ptrBits;
}

static JS_ALWAYS_INLINE jsval_layout
OBJECT_TO_JSVAL_IMPL(JSObject *obj)
{
    jsval_layout l;
    uint64 objBits = (uint64)obj;
    JS_ASSERT(obj);
    JS_ASSERT((objBits >> JSVAL_TAG_SHIFT) == 0);
    l.asBits = objBits | JSVAL_SHIFTED_TAG_OBJECT;
    return l;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_NULL_IMPL(jsval_layout l)
{
    return l.asBits == JSVAL_SHIFTED_TAG_NULL;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_GCTHING_IMPL(jsval_layout l)
{
    return l.asBits >= JSVAL_LOWER_INCL_SHIFTED_TAG_OF_GCTHING_SET;
}

static JS_ALWAYS_INLINE void *
JSVAL_TO_GCTHING_IMPL(jsval_layout l)
{
    uint64 ptrBits = l.asBits & JSVAL_PAYLOAD_MASK;
    JS_ASSERT((ptrBits & 0x7) == 0);
    return (void *)ptrBits;
}

static JS_ALWAYS_INLINE JSBool
JSVAL_IS_TRACEABLE_IMPL(jsval_layout l)
{
    return JSVAL_IS_GCTHING_IMPL(l) && !JSVAL_IS_NULL_IMPL(l);
}

static JS_ALWAYS_INLINE uint32
JSVAL_TRACE_KIND_IMPL(jsval_layout l)
{
    return (uint32)(JSBool)!(JSVAL_IS_OBJECT_IMPL(l));
}

static JS_ALWAYS_INLINE jsval_layout
PRIVATE_PTR_TO_JSVAL_IMPL(void *ptr)
{
    jsval_layout l;
    uint64 ptrBits = (uint64)ptr;
    JS_ASSERT((ptrBits & 1) == 0);
    l.asBits = ptrBits >> 1;
    JS_ASSERT(JSVAL_IS_DOUBLE_IMPL(l));
    return l;
}

static JS_ALWAYS_INLINE void *
JSVAL_TO_PRIVATE_PTR_IMPL(jsval_layout l)
{
    JS_ASSERT((l.asBits & 0x8000000000000000LL) == 0);
    return (void *)(l.asBits << 1);
}

#endif

static JS_ALWAYS_INLINE double
JS_CANONICALIZE_NAN(double d)
{
    if (JS_UNLIKELY(d != d)) {
        jsval_layout l;
        l.asBits = 0x7FF8000000000000LL;
        return l.asDouble;
    }
    return d;
}

/* See JS_USE_JSVAL_JSID_STRUCT_TYPES comment in jsapi.h. */
#if defined(DEBUG) && !defined(JS_NO_JSVAL_JSID_STRUCT_TYPES)
# define JS_USE_JSVAL_JSID_STRUCT_TYPES
#endif

#ifdef JS_USE_JSVAL_JSID_STRUCT_TYPES

typedef JSVAL_ALIGNMENT jsval_layout   jsval;
typedef struct jsid { size_t asBits; } jsid;

#if defined(__cplusplus)
extern "C++"
{
    static JS_ALWAYS_INLINE bool
    operator==(jsid lhs, jsid rhs)
    {
        return lhs.asBits == rhs.asBits;
    }

    static JS_ALWAYS_INLINE bool
    operator!=(jsid lhs, jsid rhs)
    {
        return lhs.asBits != rhs.asBits;
    }

    static JS_ALWAYS_INLINE bool
    operator==(jsval lhs, jsval rhs)
    {
        return lhs.asBits == rhs.asBits;
    }

    static JS_ALWAYS_INLINE bool
    operator!=(jsval lhs, jsval rhs)
    {
        return lhs.asBits != rhs.asBits;
    }
}
# endif /* defined(__cplusplus) */

/* Internal helper macros */
#define JSVAL_BITS(v)    ((v).asBits)
#define JSVAL_FROM_LAYOUT(l) (l)
#define IMPL_TO_JSVAL(v) (v)
#define JSID_BITS(id)    ((id).asBits)

#else /* defined(JS_USE_JSVAL_JSID_STRUCT_TYPES) */

/* Use different primitive types so overloading works. */
typedef JSVAL_ALIGNMENT uint64 jsval;
typedef ptrdiff_t              jsid;

/* Internal helper macros */
#define JSVAL_BITS(v)    (v)
#define JSVAL_FROM_LAYOUT(l) ((l).asBits)
#define IMPL_TO_JSVAL(v) ((v).asBits)
#define JSID_BITS(id)    (id)

#endif /* defined(JS_USE_JSVAL_JSID_STRUCT_TYPES) */

JS_END_EXTERN_C

#endif /* jsvalimpl_h__ */