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.

Implementation

Mercurial (b6d82b1a6b02)

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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef jit_VMFunctions_h
#define jit_VMFunctions_h

#include "mozilla/Attributes.h"
#include "mozilla/HashFunctions.h"

#include "jspubtd.h"

#include "jit/CompileInfo.h"
#include "jit/JitFrames.h"
#include "vm/Interpreter.h"

namespace js {

class ArgumentsObject;
class NamedLambdaObject;
class WithScope;
class InlineTypedObject;
class AbstractGeneratorObject;
class AsyncFunctionGeneratorObject;
class RegExpObject;
class TypedArrayObject;

namespace gc {

struct Cell;

}

namespace jit {

enum DataType : uint8_t {
  Type_Void,
  Type_Bool,
  Type_Int32,
  Type_Double,
  Type_Pointer,
  Type_Object,
  Type_Value,
  Type_Handle
};

struct PopValues {
  uint8_t numValues;

  explicit constexpr PopValues(uint8_t numValues) : numValues(numValues) {}
};

enum MaybeTailCall : bool { TailCall, NonTailCall };

// [SMDOC] JIT-to-C++ Function Calls. (callVM)
//
// Sometimes it is easier to reuse C++ code by calling VM's functions. Calling a
// function from the VM can be achieved with the use of callWithABI but this is
// discouraged when the called functions might trigger exceptions and/or
// garbage collections which are expecting to walk the stack. VMFunctions and
// callVM are interfaces provided to handle the exception handling and register
// the stack end (JITActivation) such that walking the stack is made possible.
//
// VMFunctionData is a structure which contains the necessary information needed
// for generating a trampoline function to make a call (with generateVMWrapper)
// and to root the arguments of the function (in TraceJitExitFrame).
// VMFunctionData is created with the VMFunctionDataHelper template, which
// infers the VMFunctionData fields from the function signature. The rooting and
// trampoline code is therefore determined by the arguments of a function and
// their locations in the signature of a function.
//
// VM functions all expect a JSContext* as first argument. This argument is
// implicitly provided by the trampoline code (in generateVMWrapper) and used
// for creating new objects or reporting errors. If your function does not make
// use of a JSContext* argument, then you might probably use a callWithABI
// call.
//
// Functions described using the VMFunction system must conform to a simple
// protocol: the return type must have a special "failure" value (for example,
// false for bool, or nullptr for Objects). If the function is designed to
// return a value that does not meet this requirement - such as
// object-or-nullptr, or an integer, an optional, final outParam can be
// specified. In this case, the return type must be boolean to indicate
// failure.
//
// JIT Code usage:
//
// Different JIT compilers in SpiderMonkey have their own implementations of
// callVM to call VM functions. However, the general shape of them is that
// arguments (excluding the JSContext or trailing out-param) are pushed on to
// the stack from right to left (rightmost argument is pushed first).
//
// Regardless of return value protocol being used (final outParam, or return
// value) the generated trampolines ensure the return value ends up in
// JSReturnOperand, ReturnReg or ReturnDoubleReg.
//
// Example:
//
// The details will differ slightly between the different compilers in
// SpiderMonkey, but the general shape of our usage looks like this:
//
// Suppose we have a function Foo:
//
//      bool Foo(JSContext* cx, HandleObject x, HandleId y,
//               MutableHandleValue z);
//
// This function returns true on success, and z is the outparam return value.
//
// A VM function wrapper for this can be created by adding an entry to
// VM_FUNCTION_LIST in VMFunctionList-inl.h:
//
//    _(Foo, js::Foo)
//
// In the compiler code the call would then be issued like this:
//
//      masm.Push(id);
//      masm.Push(obj);
//
//      using Fn = bool (*)(JSContext*, HandleObject, HandleId,
//                          MutableHandleValue);
//      if (!callVM<Fn, js::Foo>()) {
//          return false;
//      }
//
// After this, the result value is in the return value register.

// Data for a VM function. All VMFunctionDatas are stored in a constexpr array.
struct VMFunctionData {
#if defined(JS_JITSPEW) || defined(JS_TRACE_LOGGING)
  // Informative name of the wrapped function. The name should not be present
  // in release builds in order to save memory.
  const char* name_;
#endif

  // Note: a maximum of seven root types is supported.
  enum RootType : uint8_t {
    RootNone = 0,
    RootObject,
    RootString,
    RootId,
    RootFunction,
    RootValue,
    RootCell
  };

  // Contains an combination of enumerated types used by the gc for marking
  // arguments of the VM wrapper.
  uint64_t argumentRootTypes;

  enum ArgProperties {
    WordByValue = 0,
    DoubleByValue = 1,
    WordByRef = 2,
    DoubleByRef = 3,
    // BitMask version.
    Word = 0,
    Double = 1,
    ByRef = 2
  };

  // Contains properties about the first 16 arguments.
  uint32_t argumentProperties;

  // Which arguments should be passed in float register on platforms that
  // have them.
  uint32_t argumentPassedInFloatRegs;

  // Number of arguments expected, excluding JSContext * as an implicit
  // first argument and an outparam as a possible implicit final argument.
  uint8_t explicitArgs;

  // The root type of the out param if outParam == Type_Handle.
  RootType outParamRootType;

  // The outparam may be any Type_*, and must be the final argument to the
  // function, if not Void. outParam != Void implies that the return type
  // has a boolean failure mode.
  DataType outParam;

  // Type returned by the C function and used by the VMFunction wrapper to
  // check for failures of the C function.  Valid failure/return types are
  // boolean and object pointers which are asserted inside the VMFunction
  // constructor. If the C function use an outparam (!= Type_Void), then
  // the only valid failure/return type is boolean -- object pointers are
  // pointless because the wrapper will only use it to compare it against
  // nullptr before discarding its value.
  DataType returnType;

  // Number of Values the VM wrapper should pop from the stack when it returns.
  // Used by baseline IC stubs so that they can use tail calls to call the VM
  // wrapper.
  uint8_t extraValuesToPop;

  // On some architectures, called functions need to explicitly push their
  // return address, for a tail call, there is nothing to push, so tail-callness
  // needs to be known at compile time.
  MaybeTailCall expectTailCall;

  uint32_t argc() const {
    // JSContext * + args + (OutParam? *)
    return 1 + explicitArgc() + ((outParam == Type_Void) ? 0 : 1);
  }

  DataType failType() const { return returnType; }

  // Whether this function returns anything more than a boolean flag for
  // failures.
  bool returnsData() const {
    return returnType == Type_Object || outParam != Type_Void;
  }

  ArgProperties argProperties(uint32_t explicitArg) const {
    return ArgProperties((argumentProperties >> (2 * explicitArg)) & 3);
  }

  RootType argRootType(uint32_t explicitArg) const {
    return RootType((argumentRootTypes >> (3 * explicitArg)) & 7);
  }

  bool argPassedInFloatReg(uint32_t explicitArg) const {
    return ((argumentPassedInFloatRegs >> explicitArg) & 1) == 1;
  }

#if defined(JS_JITSPEW) || defined(JS_TRACE_LOGGING)
  const char* name() const { return name_; }
#endif

  // Return the stack size consumed by explicit arguments.
  size_t explicitStackSlots() const {
    size_t stackSlots = explicitArgs;

    // Fetch all double-word flags of explicit arguments.
    uint32_t n = ((1 << (explicitArgs * 2)) - 1)  // = Explicit argument mask.
                 & 0x55555555                     // = Mask double-size args.
                 & argumentProperties;

    // Add the number of double-word flags. (expect a few loop
    // iteration)
    while (n) {
      stackSlots++;
      n &= n - 1;
    }
    return stackSlots;
  }

  // Double-size argument which are passed by value are taking the space
  // of 2 C arguments.  This function is used to compute the number of
  // argument expected by the C function.  This is not the same as
  // explicitStackSlots because reference to stack slots may take one less
  // register in the total count.
  size_t explicitArgc() const {
    size_t stackSlots = explicitArgs;

    // Fetch all explicit arguments.
    uint32_t n = ((1 << (explicitArgs * 2)) - 1)  // = Explicit argument mask.
                 & argumentProperties;

    // Filter double-size arguments (0x5 = 0b0101) and remove (& ~)
    // arguments passed by reference (0b1010 >> 1 == 0b0101).
    n = (n & 0x55555555) & ~(n >> 1);

    // Add the number of double-word transfered by value. (expect a few
    // loop iteration)
    while (n) {
      stackSlots++;
      n &= n - 1;
    }
    return stackSlots;
  }

  size_t doubleByRefArgs() const {
    size_t count = 0;

    // Fetch all explicit arguments.
    uint32_t n = ((1 << (explicitArgs * 2)) - 1)  // = Explicit argument mask.
                 & argumentProperties;

    // Filter double-size arguments (0x5 = 0b0101) and take (&) only
    // arguments passed by reference (0b1010 >> 1 == 0b0101).
    n = (n & 0x55555555) & (n >> 1);

    // Add the number of double-word transfered by refference. (expect a
    // few loop iterations)
    while (n) {
      count++;
      n &= n - 1;
    }
    return count;
  }

  constexpr VMFunctionData(const char* name, uint32_t explicitArgs,
                           uint32_t argumentProperties,
                           uint32_t argumentPassedInFloatRegs,
                           uint64_t argRootTypes, DataType outParam,
                           RootType outParamRootType, DataType returnType,
                           uint8_t extraValuesToPop = 0,
                           MaybeTailCall expectTailCall = NonTailCall)
      :
#if defined(JS_JITSPEW) || defined(JS_TRACE_LOGGING)
        name_(name),
#endif
        argumentRootTypes(argRootTypes),
        argumentProperties(argumentProperties),
        argumentPassedInFloatRegs(argumentPassedInFloatRegs),
        explicitArgs(explicitArgs),
        outParamRootType(outParamRootType),
        outParam(outParam),
        returnType(returnType),
        extraValuesToPop(extraValuesToPop),
        expectTailCall(expectTailCall) {
    // Check for valid failure/return type.
    MOZ_ASSERT_IF(outParam != Type_Void,
                  returnType == Type_Void || returnType == Type_Bool);
    MOZ_ASSERT(returnType == Type_Void || returnType == Type_Bool ||
               returnType == Type_Object);
  }

  constexpr VMFunctionData(const VMFunctionData& o) = default;
};

template <class>
struct TypeToDataType { /* Unexpected return type for a VMFunction. */
};
template <>
struct TypeToDataType<void> {
  static const DataType result = Type_Void;
};
template <>
struct TypeToDataType<bool> {
  static const DataType result = Type_Bool;
};
template <>
struct TypeToDataType<JSObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<JSFunction*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<NativeObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<PlainObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<InlineTypedObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<NamedLambdaObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<LexicalEnvironmentObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<ArgumentsObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<ArrayObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<TypedArrayObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<ArrayIteratorObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<StringIteratorObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<RegExpStringIteratorObject*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<JSString*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<JSFlatString*> {
  static const DataType result = Type_Object;
};
template <>
struct TypeToDataType<HandleObject> {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<HandleString> {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<HandlePropertyName> {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<HandleFunction> {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<Handle<NativeObject*> > {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<Handle<InlineTypedObject*> > {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<Handle<ArrayObject*> > {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<Handle<AbstractGeneratorObject*> > {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<Handle<AsyncFunctionGeneratorObject*> > {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<Handle<PlainObject*> > {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<Handle<WithScope*> > {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<Handle<LexicalScope*> > {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<Handle<Scope*> > {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<HandleScript> {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<HandleValue> {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<MutableHandleValue> {
  static const DataType result = Type_Handle;
};
template <>
struct TypeToDataType<HandleId> {
  static const DataType result = Type_Handle;
};

// Convert argument types to properties of the argument known by the jit.
template <class T>
struct TypeToArgProperties {
  static const uint32_t result =
      (sizeof(T) <= sizeof(void*) ? VMFunctionData::Word
                                  : VMFunctionData::Double);
};
template <>
struct TypeToArgProperties<const Value&> {
  static const uint32_t result =
      TypeToArgProperties<Value>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<HandleObject> {
  static const uint32_t result =
      TypeToArgProperties<JSObject*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<HandleString> {
  static const uint32_t result =
      TypeToArgProperties<JSString*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<HandlePropertyName> {
  static const uint32_t result =
      TypeToArgProperties<PropertyName*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<HandleFunction> {
  static const uint32_t result =
      TypeToArgProperties<JSFunction*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<NativeObject*> > {
  static const uint32_t result =
      TypeToArgProperties<NativeObject*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<InlineTypedObject*> > {
  static const uint32_t result =
      TypeToArgProperties<InlineTypedObject*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<ArrayObject*> > {
  static const uint32_t result =
      TypeToArgProperties<ArrayObject*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<AbstractGeneratorObject*> > {
  static const uint32_t result =
      TypeToArgProperties<AbstractGeneratorObject*>::result |
      VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<AsyncFunctionGeneratorObject*> > {
  static const uint32_t result =
      TypeToArgProperties<AsyncFunctionGeneratorObject*>::result |
      VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<PlainObject*> > {
  static const uint32_t result =
      TypeToArgProperties<PlainObject*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<RegExpObject*> > {
  static const uint32_t result =
      TypeToArgProperties<RegExpObject*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<WithScope*> > {
  static const uint32_t result =
      TypeToArgProperties<WithScope*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<LexicalScope*> > {
  static const uint32_t result =
      TypeToArgProperties<LexicalScope*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<Handle<Scope*> > {
  static const uint32_t result =
      TypeToArgProperties<Scope*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<HandleScript> {
  static const uint32_t result =
      TypeToArgProperties<JSScript*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<HandleValue> {
  static const uint32_t result =
      TypeToArgProperties<Value>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<MutableHandleValue> {
  static const uint32_t result =
      TypeToArgProperties<Value>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<HandleId> {
  static const uint32_t result =
      TypeToArgProperties<jsid>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<HandleShape> {
  static const uint32_t result =
      TypeToArgProperties<Shape*>::result | VMFunctionData::ByRef;
};
template <>
struct TypeToArgProperties<HandleObjectGroup> {
  static const uint32_t result =
      TypeToArgProperties<ObjectGroup*>::result | VMFunctionData::ByRef;
};

// Convert argument type to whether or not it should be passed in a float
// register on platforms that have them, like x64.
template <class T>
struct TypeToPassInFloatReg {
  static const uint32_t result = 0;
};
template <>
struct TypeToPassInFloatReg<double> {
  static const uint32_t result = 1;
};

// Convert argument types to root types used by the gc, see MarkJitExitFrame.
template <class T>
struct TypeToRootType {
  static const uint32_t result = VMFunctionData::RootNone;
};
template <>
struct TypeToRootType<HandleObject> {
  static const uint32_t result = VMFunctionData::RootObject;
};
template <>
struct TypeToRootType<HandleString> {
  static const uint32_t result = VMFunctionData::RootString;
};
template <>
struct TypeToRootType<HandlePropertyName> {
  static const uint32_t result = VMFunctionData::RootString;
};
template <>
struct TypeToRootType<HandleFunction> {
  static const uint32_t result = VMFunctionData::RootFunction;
};
template <>
struct TypeToRootType<HandleValue> {
  static const uint32_t result = VMFunctionData::RootValue;
};
template <>
struct TypeToRootType<MutableHandleValue> {
  static const uint32_t result = VMFunctionData::RootValue;
};
template <>
struct TypeToRootType<HandleId> {
  static const uint32_t result = VMFunctionData::RootId;
};
template <>
struct TypeToRootType<HandleShape> {
  static const uint32_t result = VMFunctionData::RootCell;
};
template <>
struct TypeToRootType<HandleObjectGroup> {
  static const uint32_t result = VMFunctionData::RootCell;
};
template <>
struct TypeToRootType<HandleScript> {
  static const uint32_t result = VMFunctionData::RootCell;
};
template <>
struct TypeToRootType<Handle<NativeObject*> > {
  static const uint32_t result = VMFunctionData::RootObject;
};
template <>
struct TypeToRootType<Handle<InlineTypedObject*> > {
  static const uint32_t result = VMFunctionData::RootObject;
};
template <>
struct TypeToRootType<Handle<ArrayObject*> > {
  static const uint32_t result = VMFunctionData::RootObject;
};
template <>
struct TypeToRootType<Handle<AbstractGeneratorObject*> > {
  static const uint32_t result = VMFunctionData::RootObject;
};
template <>
struct TypeToRootType<Handle<AsyncFunctionGeneratorObject*> > {
  static const uint32_t result = VMFunctionData::RootObject;
};
template <>
struct TypeToRootType<Handle<PlainObject*> > {
  static const uint32_t result = VMFunctionData::RootObject;
};
template <>
struct TypeToRootType<Handle<RegExpObject*> > {
  static const uint32_t result = VMFunctionData::RootObject;
};
template <>
struct TypeToRootType<Handle<LexicalScope*> > {
  static const uint32_t result = VMFunctionData::RootCell;
};
template <>
struct TypeToRootType<Handle<WithScope*> > {
  static const uint32_t result = VMFunctionData::RootCell;
};
template <>
struct TypeToRootType<Handle<Scope*> > {
  static const uint32_t result = VMFunctionData::RootCell;
};
template <class T>
struct TypeToRootType<Handle<T> > {
  // Fail for Handle types that aren't specialized above.
};

template <class>
struct OutParamToDataType {
  static const DataType result = Type_Void;
};
template <>
struct OutParamToDataType<Value*> {
  static const DataType result = Type_Value;
};
template <>
struct OutParamToDataType<int*> {
  static const DataType result = Type_Int32;
};
template <>
struct OutParamToDataType<uint32_t*> {
  static const DataType result = Type_Int32;
};
template <>
struct OutParamToDataType<uint8_t**> {
  static const DataType result = Type_Pointer;
};
template <>
struct OutParamToDataType<bool*> {
  static const DataType result = Type_Bool;
};
template <>
struct OutParamToDataType<double*> {
  static const DataType result = Type_Double;
};
template <>
struct OutParamToDataType<MutableHandleValue> {
  static const DataType result = Type_Handle;
};
template <>
struct OutParamToDataType<MutableHandleObject> {
  static const DataType result = Type_Handle;
};
template <>
struct OutParamToDataType<MutableHandleString> {
  static const DataType result = Type_Handle;
};

template <class>
struct OutParamToRootType {
  static const VMFunctionData::RootType result = VMFunctionData::RootNone;
};
template <>
struct OutParamToRootType<MutableHandleValue> {
  static const VMFunctionData::RootType result = VMFunctionData::RootValue;
};
template <>
struct OutParamToRootType<MutableHandleObject> {
  static const VMFunctionData::RootType result = VMFunctionData::RootObject;
};
template <>
struct OutParamToRootType<MutableHandleString> {
  static const VMFunctionData::RootType result = VMFunctionData::RootString;
};

// Extract the last element of a list of types.
template <typename... ArgTypes>
struct LastArg;

template <>
struct LastArg<> {
  typedef void Type;
  static constexpr size_t nbArgs = 0;
};

template <typename HeadType>
struct LastArg<HeadType> {
  typedef HeadType Type;
  static constexpr size_t nbArgs = 1;
};

template <typename HeadType, typename... TailTypes>
struct LastArg<HeadType, TailTypes...> {
  typedef typename LastArg<TailTypes...>::Type Type;
  static constexpr size_t nbArgs = LastArg<TailTypes...>::nbArgs + 1;
};

// Construct a bit mask from a list of types.  The mask is constructed as an OR
// of the mask produced for each argument. The result of each argument is
// shifted by its index, such that the result of the first argument is on the
// low bits of the mask, and the result of the last argument in part of the
// high bits of the mask.
template <template <typename> class Each, typename ResultType, size_t Shift,
          typename... Args>
struct BitMask;

template <template <typename> class Each, typename ResultType, size_t Shift>
struct BitMask<Each, ResultType, Shift> {
  static constexpr ResultType result = ResultType();
};

template <template <typename> class Each, typename ResultType, size_t Shift,
          typename HeadType, typename... TailTypes>
struct BitMask<Each, ResultType, Shift, HeadType, TailTypes...> {
  static_assert(ResultType(Each<HeadType>::result) < (1 << Shift),
                "not enough bits reserved by the shift for individual results");
  static_assert(LastArg<TailTypes...>::nbArgs <
                    (8 * sizeof(ResultType) / Shift),
                "not enough bits in the result type to store all bit masks");

  static constexpr ResultType result =
      ResultType(Each<HeadType>::result) |
      (BitMask<Each, ResultType, Shift, TailTypes...>::result << Shift);
};

class AutoDetectInvalidation {
  JSContext* cx_;
  IonScript* ionScript_;
  MutableHandleValue rval_;
  bool disabled_;

  void setReturnOverride();

 public:
  AutoDetectInvalidation(JSContext* cx, MutableHandleValue rval,
                         IonScript* ionScript)
      : cx_(cx), ionScript_(ionScript), rval_(rval), disabled_(false) {
    MOZ_ASSERT(ionScript);
  }

  AutoDetectInvalidation(JSContext* cx, MutableHandleValue rval);

  void disable() {
    MOZ_ASSERT(!disabled_);
    disabled_ = true;
  }

  bool shouldSetReturnOverride() const {
    return !disabled_ && ionScript_->invalidated();
  }

  ~AutoDetectInvalidation() {
    if (MOZ_UNLIKELY(shouldSetReturnOverride())) {
      setReturnOverride();
    }
  }
};

MOZ_MUST_USE bool InvokeFunction(JSContext* cx, HandleObject obj0,
                                 bool constructing, bool ignoresReturnValue,
                                 uint32_t argc, Value* argv,
                                 MutableHandleValue rval);
MOZ_MUST_USE bool InvokeFunctionShuffleNewTarget(
    JSContext* cx, HandleObject obj, uint32_t numActualArgs,
    uint32_t numFormalArgs, Value* argv, MutableHandleValue rval);

class InterpreterStubExitFrameLayout;
bool InvokeFromInterpreterStub(JSContext* cx,
                               InterpreterStubExitFrameLayout* frame);

bool CheckOverRecursed(JSContext* cx);
bool CheckOverRecursedBaseline(JSContext* cx, BaselineFrame* frame);

MOZ_MUST_USE bool MutatePrototype(JSContext* cx, HandlePlainObject obj,
                                  HandleValue value);
MOZ_MUST_USE bool InitProp(JSContext* cx, HandleObject obj,
                           HandlePropertyName name, HandleValue value,
                           jsbytecode* pc);

enum class EqualityKind : bool { NotEqual, Equal };

template <EqualityKind Kind>
bool LooselyEqual(JSContext* cx, MutableHandleValue lhs, MutableHandleValue rhs,
                  bool* res);

template <EqualityKind Kind>
bool StrictlyEqual(JSContext* cx, MutableHandleValue lhs,
                   MutableHandleValue rhs, bool* res);

bool LessThan(JSContext* cx, MutableHandleValue lhs, MutableHandleValue rhs,
              bool* res);
bool LessThanOrEqual(JSContext* cx, MutableHandleValue lhs,
                     MutableHandleValue rhs, bool* res);
bool GreaterThan(JSContext* cx, MutableHandleValue lhs, MutableHandleValue rhs,
                 bool* res);
bool GreaterThanOrEqual(JSContext* cx, MutableHandleValue lhs,
                        MutableHandleValue rhs, bool* res);

template <EqualityKind Kind>
bool StringsEqual(JSContext* cx, HandleString lhs, HandleString rhs, bool* res);

enum class ComparisonKind : bool { GreaterThanOrEqual, LessThan };

template <ComparisonKind Kind>
bool StringsCompare(JSContext* cx, HandleString lhs, HandleString rhs,
                    bool* res);

MOZ_MUST_USE bool ArrayPopDense(JSContext* cx, HandleObject obj,
                                MutableHandleValue rval);
MOZ_MUST_USE bool ArrayPushDense(JSContext* cx, HandleArrayObject arr,
                                 HandleValue v, uint32_t* length);
MOZ_MUST_USE bool ArrayShiftDense(JSContext* cx, HandleObject obj,
                                  MutableHandleValue rval);
JSString* ArrayJoin(JSContext* cx, HandleObject array, HandleString sep);
MOZ_MUST_USE bool SetArrayLength(JSContext* cx, HandleObject obj,
                                 HandleValue value, bool strict);

MOZ_MUST_USE bool CharCodeAt(JSContext* cx, HandleString str, int32_t index,
                             uint32_t* code);
JSFlatString* StringFromCharCode(JSContext* cx, int32_t code);
JSString* StringFromCodePoint(JSContext* cx, int32_t codePoint);

MOZ_MUST_USE bool SetProperty(JSContext* cx, HandleObject obj,
                              HandlePropertyName name, HandleValue value,
                              bool strict, jsbytecode* pc);

MOZ_MUST_USE bool InterruptCheck(JSContext* cx);

JSObject* NewCallObject(JSContext* cx, HandleShape shape,
                        HandleObjectGroup group);
JSObject* NewStringObject(JSContext* cx, HandleString str);

bool OperatorIn(JSContext* cx, HandleValue key, HandleObject obj, bool* out);
bool OperatorInI(JSContext* cx, uint32_t index, HandleObject obj, bool* out);

MOZ_MUST_USE bool GetIntrinsicValue(JSContext* cx, HandlePropertyName name,
                                    MutableHandleValue rval);

MOZ_MUST_USE bool CreateThis(JSContext* cx, HandleObject callee,
                             HandleObject newTarget, MutableHandleValue rval);

bool GetDynamicNamePure(JSContext* cx, JSObject* scopeChain, JSString* str,
                        Value* vp);

void PostWriteBarrier(JSRuntime* rt, js::gc::Cell* cell);
void PostGlobalWriteBarrier(JSRuntime* rt, GlobalObject* obj);

enum class IndexInBounds { Yes, Maybe };

template <IndexInBounds InBounds>
void PostWriteElementBarrier(JSRuntime* rt, JSObject* obj, int32_t index);

// If |str| is an index in the range [0, INT32_MAX], return it. If the string
// is not an index in this range, return -1.
int32_t GetIndexFromString(JSString* str);

JSObject* WrapObjectPure(JSContext* cx, JSObject* obj);

MOZ_MUST_USE bool DebugPrologue(JSContext* cx, BaselineFrame* frame,
                                jsbytecode* pc, bool* mustReturn);
MOZ_MUST_USE bool DebugEpilogue(JSContext* cx, BaselineFrame* frame,
                                jsbytecode* pc, bool ok);
MOZ_MUST_USE bool DebugEpilogueOnBaselineReturn(JSContext* cx,
                                                BaselineFrame* frame,
                                                jsbytecode* pc);
void FrameIsDebuggeeCheck(BaselineFrame* frame);

JSObject* CreateGenerator(JSContext* cx, BaselineFrame* frame);

MOZ_MUST_USE bool NormalSuspend(JSContext* cx, HandleObject obj,
                                BaselineFrame* frame, jsbytecode* pc);
MOZ_MUST_USE bool FinalSuspend(JSContext* cx, HandleObject obj, jsbytecode* pc);
MOZ_MUST_USE bool InterpretResume(JSContext* cx, HandleObject obj,
                                  HandleValue val, HandlePropertyName kind,
                                  MutableHandleValue rval);
MOZ_MUST_USE bool DebugAfterYield(JSContext* cx, BaselineFrame* frame,
                                  jsbytecode* pc, bool* mustReturn);
MOZ_MUST_USE bool GeneratorThrowOrReturn(
    JSContext* cx, BaselineFrame* frame,
    Handle<AbstractGeneratorObject*> genObj, HandleValue arg,
    uint32_t resumeKindArg);

MOZ_MUST_USE bool GlobalNameConflictsCheckFromIon(JSContext* cx,
                                                  HandleScript script);
MOZ_MUST_USE bool InitFunctionEnvironmentObjects(JSContext* cx,
                                                 BaselineFrame* frame);

MOZ_MUST_USE bool NewArgumentsObject(JSContext* cx, BaselineFrame* frame,
                                     MutableHandleValue res);

JSObject* CopyLexicalEnvironmentObject(JSContext* cx, HandleObject env,
                                       bool copySlots);

JSObject* InitRestParameter(JSContext* cx, uint32_t length, Value* rest,
                            HandleObject templateObj, HandleObject res);

MOZ_MUST_USE bool HandleDebugTrap(JSContext* cx, BaselineFrame* frame,
                                  uint8_t* retAddr, bool* mustReturn);
MOZ_MUST_USE bool OnDebuggerStatement(JSContext* cx, BaselineFrame* frame,
                                      jsbytecode* pc, bool* mustReturn);
MOZ_MUST_USE bool GlobalHasLiveOnDebuggerStatement(JSContext* cx);

MOZ_MUST_USE bool EnterWith(JSContext* cx, BaselineFrame* frame,
                            HandleValue val, Handle<WithScope*> templ);
MOZ_MUST_USE bool LeaveWith(JSContext* cx, BaselineFrame* frame);

MOZ_MUST_USE bool PushLexicalEnv(JSContext* cx, BaselineFrame* frame,
                                 Handle<LexicalScope*> scope);
MOZ_MUST_USE bool PopLexicalEnv(JSContext* cx, BaselineFrame* frame);
MOZ_MUST_USE bool DebugLeaveThenPopLexicalEnv(JSContext* cx,
                                              BaselineFrame* frame,
                                              jsbytecode* pc);
MOZ_MUST_USE bool FreshenLexicalEnv(JSContext* cx, BaselineFrame* frame);
MOZ_MUST_USE bool DebugLeaveThenFreshenLexicalEnv(JSContext* cx,
                                                  BaselineFrame* frame,
                                                  jsbytecode* pc);
MOZ_MUST_USE bool RecreateLexicalEnv(JSContext* cx, BaselineFrame* frame);
MOZ_MUST_USE bool DebugLeaveThenRecreateLexicalEnv(JSContext* cx,
                                                   BaselineFrame* frame,
                                                   jsbytecode* pc);
MOZ_MUST_USE bool DebugLeaveLexicalEnv(JSContext* cx, BaselineFrame* frame,
                                       jsbytecode* pc);

MOZ_MUST_USE bool PushVarEnv(JSContext* cx, BaselineFrame* frame,
                             HandleScope scope);
MOZ_MUST_USE bool PopVarEnv(JSContext* cx, BaselineFrame* frame);

MOZ_MUST_USE bool InitBaselineFrameForOsr(BaselineFrame* frame,
                                          InterpreterFrame* interpFrame,
                                          uint32_t numStackValues);

JSObject* CreateDerivedTypedObj(JSContext* cx, HandleObject descr,
                                HandleObject owner, int32_t offset);

MOZ_MUST_USE bool IonRecompile(JSContext* cx);
MOZ_MUST_USE bool IonForcedRecompile(JSContext* cx);
MOZ_MUST_USE bool IonForcedInvalidation(JSContext* cx);

JSString* StringReplace(JSContext* cx, HandleString string,
                        HandleString pattern, HandleString repl);

MOZ_MUST_USE bool SetDenseElement(JSContext* cx, HandleNativeObject obj,
                                  int32_t index, HandleValue value,
                                  bool strict);

void AssertValidObjectPtr(JSContext* cx, JSObject* obj);
void AssertValidObjectOrNullPtr(JSContext* cx, JSObject* obj);
void AssertValidStringPtr(JSContext* cx, JSString* str);
void AssertValidSymbolPtr(JSContext* cx, JS::Symbol* sym);
void AssertValidBigIntPtr(JSContext* cx, JS::BigInt* bi);
void AssertValidValue(JSContext* cx, Value* v);

void MarkValueFromJit(JSRuntime* rt, Value* vp);
void MarkStringFromJit(JSRuntime* rt, JSString** stringp);
void MarkObjectFromJit(JSRuntime* rt, JSObject** objp);
void MarkShapeFromJit(JSRuntime* rt, Shape** shapep);
void MarkObjectGroupFromJit(JSRuntime* rt, ObjectGroup** groupp);

// Helper for generatePreBarrier.
inline void* JitMarkFunction(MIRType type) {
  switch (type) {
    case MIRType::Value:
      return JS_FUNC_TO_DATA_PTR(void*, MarkValueFromJit);
    case MIRType::String:
      return JS_FUNC_TO_DATA_PTR(void*, MarkStringFromJit);
    case MIRType::Object:
      return JS_FUNC_TO_DATA_PTR(void*, MarkObjectFromJit);
    case MIRType::Shape:
      return JS_FUNC_TO_DATA_PTR(void*, MarkShapeFromJit);
    case MIRType::ObjectGroup:
      return JS_FUNC_TO_DATA_PTR(void*, MarkObjectGroupFromJit);
    default:
      MOZ_CRASH();
  }
}

bool ObjectIsCallable(JSObject* obj);
bool ObjectIsConstructor(JSObject* obj);

MOZ_MUST_USE bool ThrowRuntimeLexicalError(JSContext* cx, unsigned errorNumber);

MOZ_MUST_USE bool BaselineThrowUninitializedThis(JSContext* cx,
                                                 BaselineFrame* frame);

MOZ_MUST_USE bool BaselineThrowInitializedThis(JSContext* cx);

MOZ_MUST_USE bool ThrowBadDerivedReturn(JSContext* cx, HandleValue v);

MOZ_MUST_USE bool ThrowObjectCoercible(JSContext* cx, HandleValue v);

MOZ_MUST_USE bool BaselineGetFunctionThis(JSContext* cx, BaselineFrame* frame,
                                          MutableHandleValue res);

MOZ_MUST_USE bool CallNativeGetter(JSContext* cx, HandleFunction callee,
                                   HandleObject obj, MutableHandleValue result);

MOZ_MUST_USE bool CallNativeGetterByValue(JSContext* cx, HandleFunction callee,
                                          HandleValue receiver,
                                          MutableHandleValue result);

MOZ_MUST_USE bool CallNativeSetter(JSContext* cx, HandleFunction callee,
                                   HandleObject obj, HandleValue rhs);

MOZ_MUST_USE bool EqualStringsHelperPure(JSString* str1, JSString* str2);

MOZ_MUST_USE bool CheckIsCallable(JSContext* cx, HandleValue v,
                                  CheckIsCallableKind kind);

void HandleCodeCoverageAtPC(BaselineFrame* frame, jsbytecode* pc);
void HandleCodeCoverageAtPrologue(BaselineFrame* frame);

template <bool HandleMissing>
bool GetNativeDataPropertyPure(JSContext* cx, JSObject* obj, PropertyName* name,
                               Value* vp);

template <bool HandleMissing>
bool GetNativeDataPropertyByValuePure(JSContext* cx, JSObject* obj, Value* vp);

template <bool HasOwn>
bool HasNativeDataPropertyPure(JSContext* cx, JSObject* obj, Value* vp);

bool HasNativeElementPure(JSContext* cx, NativeObject* obj, int32_t index,
                          Value* vp);

template <bool NeedsTypeBarrier>
bool SetNativeDataPropertyPure(JSContext* cx, JSObject* obj, PropertyName* name,
                               Value* val);

bool ObjectHasGetterSetterPure(JSContext* cx, JSObject* obj, Shape* propShape);

JSString* TypeOfObject(JSObject* obj, JSRuntime* rt);

bool GetPrototypeOf(JSContext* cx, HandleObject target,
                    MutableHandleValue rval);

bool DoConcatStringObject(JSContext* cx, HandleValue lhs, HandleValue rhs,
                          MutableHandleValue res);

// Wrapper for js::TrySkipAwait.
// If the await operation can be skipped and the resolution value for `val` can
// be acquired, stored the resolved value to `resolved`.  Otherwise, stores
// the JS_CANNOT_SKIP_AWAIT magic value to `resolved`.
MOZ_MUST_USE bool TrySkipAwait(JSContext* cx, HandleValue val,
                               MutableHandleValue resolved);

bool IsPossiblyWrappedTypedArray(JSContext* cx, JSObject* obj, bool* result);

bool DoToNumber(JSContext* cx, HandleValue arg, MutableHandleValue ret);
bool DoToNumeric(JSContext* cx, HandleValue arg, MutableHandleValue ret);

enum class TailCallVMFunctionId;
enum class VMFunctionId;

extern const VMFunctionData& GetVMFunction(VMFunctionId id);
extern const VMFunctionData& GetVMFunction(TailCallVMFunctionId id);

}  // namespace jit
}  // namespace js

#endif /* jit_VMFunctions_h */