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.

Header

Mercurial (5b81998bb7ab)

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 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=4 sw=4 et tw=99:
 *
 * 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/. */

#include "jscntxt.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsscope.h"

#include "assembler/assembler/LinkBuffer.h"
#include "assembler/assembler/MacroAssembler.h"
#include "assembler/assembler/CodeLocation.h"

#include "methodjit/CodeGenIncludes.h"
#include "methodjit/Compiler.h"
#include "methodjit/ICRepatcher.h"
#include "methodjit/InlineFrameAssembler.h"
#include "methodjit/MonoIC.h"
#include "methodjit/PolyIC.h"
#include "methodjit/StubCalls.h"

#include "builtin/RegExp.h"

#include "jsinterpinlines.h"
#include "jsobjinlines.h"
#include "jsscopeinlines.h"
#include "jsscriptinlines.h"

#include "methodjit/StubCalls-inl.h"

using namespace js;
using namespace js::mjit;
using namespace js::mjit::ic;

typedef JSC::MacroAssembler::RegisterID RegisterID;
typedef JSC::MacroAssembler::Address Address;
typedef JSC::MacroAssembler::Jump Jump;
typedef JSC::MacroAssembler::Imm32 Imm32;
typedef JSC::MacroAssembler::ImmPtr ImmPtr;
typedef JSC::MacroAssembler::Call Call;
typedef JSC::MacroAssembler::Label Label;
typedef JSC::MacroAssembler::DataLabel32 DataLabel32;
typedef JSC::MacroAssembler::DataLabelPtr DataLabelPtr;

#if defined JS_MONOIC

static void
PatchGetFallback(VMFrame &f, ic::GetGlobalNameIC *ic)
{
    Repatcher repatch(f.chunk());
    JSC::FunctionPtr fptr(JS_FUNC_TO_DATA_PTR(void *, stubs::Name));
    repatch.relink(ic->slowPathCall, fptr);
}

void JS_FASTCALL
ic::GetGlobalName(VMFrame &f, ic::GetGlobalNameIC *ic)
{
    RootedObject obj(f.cx, &f.fp()->global());
    PropertyName *name = f.script()->getName(GET_UINT32_INDEX(f.pc()));

    RecompilationMonitor monitor(f.cx);

    Shape *shape = obj->nativeLookup(f.cx, NameToId(name));

    if (monitor.recompiled()) {
        stubs::Name(f);
        return;
    }

    if (!shape ||
        !shape->hasDefaultGetter() ||
        !shape->hasSlot())
    {
        if (shape)
            PatchGetFallback(f, ic);
        stubs::Name(f);
        return;
    }
    uint32_t slot = shape->slot();

    /* Patch shape guard. */
    Repatcher repatcher(f.chunk());
    repatcher.repatch(ic->fastPathStart.dataLabelPtrAtOffset(ic->shapeOffset), obj->lastProperty());

    /* Patch loads. */
    uint32_t index = obj->dynamicSlotIndex(slot);
    JSC::CodeLocationLabel label = ic->fastPathStart.labelAtOffset(ic->loadStoreOffset);
    repatcher.patchAddressOffsetForValueLoad(label, index * sizeof(Value));

    /* Do load anyway... this time. */
    stubs::Name(f);
}

static void JS_FASTCALL
DisabledSetGlobal(VMFrame &f, ic::SetGlobalNameIC *ic)
{
    stubs::SetName(f, f.script()->getName(GET_UINT32_INDEX(f.pc())));
}

static void
PatchSetFallback(VMFrame &f, ic::SetGlobalNameIC *ic)
{
    Repatcher repatch(f.chunk());
    VoidStubSetGlobal stub = DisabledSetGlobal;
    JSC::FunctionPtr fptr(JS_FUNC_TO_DATA_PTR(void *, stub));
    repatch.relink(ic->slowPathCall, fptr);
}

void
SetGlobalNameIC::patchInlineShapeGuard(Repatcher &repatcher, Shape *shape)
{
    JSC::CodeLocationDataLabelPtr label = fastPathStart.dataLabelPtrAtOffset(shapeOffset);
    repatcher.repatch(label, shape);
}

static LookupStatus
UpdateSetGlobalName(VMFrame &f, ic::SetGlobalNameIC *ic, JSObject *obj, Shape *shape)
{
    /* Give globals a chance to appear. */
    if (!shape)
        return Lookup_Uncacheable;

    if (!shape->hasDefaultSetter() ||
        !shape->writable() ||
        !shape->hasSlot() ||
        obj->watched())
    {
        /* Disable the IC for weird shape attributes and watchpoints. */
        PatchSetFallback(f, ic);
        return Lookup_Uncacheable;
    }

    /* Object is not branded, so we can use the inline path. */
    Repatcher repatcher(f.chunk());
    ic->patchInlineShapeGuard(repatcher, obj->lastProperty());

    uint32_t index = obj->dynamicSlotIndex(shape->slot());
    JSC::CodeLocationLabel label = ic->fastPathStart.labelAtOffset(ic->loadStoreOffset);
    repatcher.patchAddressOffsetForValueStore(label, index * sizeof(Value),
                                              ic->vr.isTypeKnown());

    return Lookup_Cacheable;
}

void JS_FASTCALL
ic::SetGlobalName(VMFrame &f, ic::SetGlobalNameIC *ic)
{
    RootedObject obj(f.cx, &f.fp()->global());
    RootedPropertyName name(f.cx, f.script()->getName(GET_UINT32_INDEX(f.pc())));

    RecompilationMonitor monitor(f.cx);

    Shape *shape = obj->nativeLookup(f.cx, NameToId(name));

    if (!monitor.recompiled()) {
        LookupStatus status = UpdateSetGlobalName(f, ic, obj, shape);
        if (status == Lookup_Error)
            THROW();
    }

    stubs::SetName(f, name);
}

class EqualityICLinker : public LinkerHelper
{
    VMFrame &f;

  public:
    EqualityICLinker(Assembler &masm, VMFrame &f)
        : LinkerHelper(masm, JSC::METHOD_CODE), f(f)
    { }

    bool init(JSContext *cx) {
        JSC::ExecutablePool *pool = LinkerHelper::init(cx);
        if (!pool)
            return false;
        JS_ASSERT(!f.regs.inlined());
        if (!f.chunk()->execPools.append(pool)) {
            markVerified();
            pool->release();
            js_ReportOutOfMemory(cx);
            return false;
        }
        return true;
    }
};

/* Rough over-estimate of how much memory we need to unprotect. */
static const uint32_t INLINE_PATH_LENGTH = 64;

class EqualityCompiler : public BaseCompiler
{
    VMFrame &f;
    EqualityICInfo ⁣

    Vector<Jump, 4, SystemAllocPolicy> jumpList;
    Jump trueJump;
    Jump falseJump;

  public:
    EqualityCompiler(VMFrame &f, EqualityICInfo &ic)
        : BaseCompiler(f.cx), f(f), ic(ic), jumpList(SystemAllocPolicy())
    {
    }

    void linkToStub(Jump j)
    {
        jumpList.append(j);
    }

    void linkTrue(Jump j)
    {
        trueJump = j;
    }

    void linkFalse(Jump j)
    {
        falseJump = j;
    }

    void generateStringPath(Assembler &masm)
    {
        const ValueRemat &lvr = ic.lvr;
        const ValueRemat &rvr = ic.rvr;

        JS_ASSERT_IF(lvr.isConstant(), lvr.isType(JSVAL_TYPE_STRING));
        JS_ASSERT_IF(rvr.isConstant(), rvr.isType(JSVAL_TYPE_STRING));

        if (!lvr.isType(JSVAL_TYPE_STRING)) {
            Jump lhsFail = masm.testString(Assembler::NotEqual, lvr.typeReg());
            linkToStub(lhsFail);
        }

        if (!rvr.isType(JSVAL_TYPE_STRING)) {
            Jump rhsFail = masm.testString(Assembler::NotEqual, rvr.typeReg());
            linkToStub(rhsFail);
        }

        RegisterID tmp = ic.tempReg;

        /* JSString::isAtom === (lengthAndFlags & ATOM_BIT) */
        Imm32 atomBit(JSString::ATOM_BIT);

        masm.load32(Address(lvr.dataReg(), JSString::offsetOfLengthAndFlags()), tmp);
        Jump lhsNotAtomized = masm.branchTest32(Assembler::Zero, tmp, atomBit);
        linkToStub(lhsNotAtomized);

        if (!rvr.isConstant()) {
            masm.load32(Address(rvr.dataReg(), JSString::offsetOfLengthAndFlags()), tmp);
            Jump rhsNotAtomized = masm.branchTest32(Assembler::Zero, tmp, atomBit);
            linkToStub(rhsNotAtomized);
        }

        if (rvr.isConstant()) {
            JSString *str = rvr.value().toString();
            JS_ASSERT(str->isAtom());
            Jump test = masm.branchPtr(ic.cond, lvr.dataReg(), ImmPtr(str));
            linkTrue(test);
        } else {
            Jump test = masm.branchPtr(ic.cond, lvr.dataReg(), rvr.dataReg());
            linkTrue(test);
        }

        Jump fallthrough = masm.jump();
        linkFalse(fallthrough);
    }

    void generateObjectPath(Assembler &masm)
    {
        ValueRemat &lvr = ic.lvr;
        ValueRemat &rvr = ic.rvr;

        if (!lvr.isConstant() && !lvr.isType(JSVAL_TYPE_OBJECT)) {
            Jump lhsFail = masm.testObject(Assembler::NotEqual, lvr.typeReg());
            linkToStub(lhsFail);
        }

        if (!rvr.isConstant() && !rvr.isType(JSVAL_TYPE_OBJECT)) {
            Jump rhsFail = masm.testObject(Assembler::NotEqual, rvr.typeReg());
            linkToStub(rhsFail);
        }

        masm.loadObjClass(lvr.dataReg(), ic.tempReg);
        Jump lhsHasEq = masm.branchPtr(Assembler::NotEqual,
                                       Address(ic.tempReg, offsetof(Class, ext.equality)),
                                       ImmPtr(NULL));
        linkToStub(lhsHasEq);

        if (rvr.isConstant()) {
            JSObject *obj = &rvr.value().toObject();
            Jump test = masm.branchPtr(ic.cond, lvr.dataReg(), ImmPtr(obj));
            linkTrue(test);
        } else {
            Jump test = masm.branchPtr(ic.cond, lvr.dataReg(), rvr.dataReg());
            linkTrue(test);
        }

        Jump fallthrough = masm.jump();
        linkFalse(fallthrough);
    }

    bool linkForIC(Assembler &masm)
    {
        EqualityICLinker buffer(masm, f);
        if (!buffer.init(cx))
            return false;

        Repatcher repatcher(f.chunk());

        /* Overwrite the call to the IC with a call to the stub. */
        JSC::FunctionPtr fptr(JS_FUNC_TO_DATA_PTR(void *, ic.stub));
        repatcher.relink(ic.stubCall, fptr);

        // Silently fail, the IC is disabled now.
        if (!buffer.verifyRange(f.chunk()))
            return true;

        /* Set the targets of all type test failures to go to the stub. */
        for (size_t i = 0; i < jumpList.length(); i++)
            buffer.link(jumpList[i], ic.stubEntry);
        jumpList.clear();

        /* Set the targets for the the success and failure of the actual equality test. */
        buffer.link(trueJump, ic.target);
        buffer.link(falseJump, ic.fallThrough);

        CodeLocationLabel cs = buffer.finalize(f);

        /* Jump to the newly generated code instead of to the IC. */
        repatcher.relink(ic.jumpToStub, cs);

        return true;
    }

    bool update()
    {
        if (!ic.generated) {
            SPSInstrumentation sps(&f);
            Assembler masm(&sps);
            Value rval = f.regs.sp[-1];
            Value lval = f.regs.sp[-2];

            if (rval.isObject() && lval.isObject()) {
                generateObjectPath(masm);
                ic.generated = true;
            } else if (rval.isString() && lval.isString()) {
                generateStringPath(masm);
                ic.generated = true;
            } else {
                return true;
            }

            return linkForIC(masm);
        }

        return true;
    }
};

JSBool JS_FASTCALL
ic::Equality(VMFrame &f, ic::EqualityICInfo *ic)
{
    EqualityCompiler cc(f, *ic);
    if (!cc.update())
        THROWV(JS_FALSE);

    return ic->stub(f);
}

static void * JS_FASTCALL
SlowCallFromIC(VMFrame &f, ic::CallICInfo *ic)
{
    stubs::SlowCall(f, ic->frameSize.getArgc(f));
    return NULL;
}

static void * JS_FASTCALL
SlowNewFromIC(VMFrame &f, ic::CallICInfo *ic)
{
    stubs::SlowNew(f, ic->frameSize.staticArgc());
    return NULL;
}

bool
NativeStubLinker::init(JSContext *cx)
{
    JSC::ExecutablePool *pool = LinkerHelper::init(cx);
    if (!pool)
        return false;

    NativeCallStub stub;
    stub.pc = pc;
    stub.pool = pool;
    stub.jump = locationOf(done);
    if (!chunk->nativeCallStubs.append(stub)) {
        markVerified();
        pool->release();
        return false;
    }

    return true;
}

/*
 * Generate epilogue code to run after a stub ABI call to a native or getter.
 * This checks for an exception, and either type checks the result against the
 * observed types for the opcode or loads the result into a register pair
 * (it will go through a type barrier afterwards).
 */
bool
mjit::NativeStubEpilogue(VMFrame &f, Assembler &masm, NativeStubLinker::FinalJump *result,
                         int32_t initialFrameDepth, int32_t vpOffset,
                         MaybeRegisterID typeReg, MaybeRegisterID dataReg)
{
    /* Reload fp, which may have been clobbered by restoreStackBase(). */
    masm.loadPtr(FrameAddress(VMFrame::offsetOfFp), JSFrameReg);

    Jump hasException = masm.branchTest32(Assembler::Zero, Registers::ReturnReg,
                                          Registers::ReturnReg);

    Address resultAddress(JSFrameReg, vpOffset);

    Vector<Jump> mismatches(f.cx);
    if (f.cx->typeInferenceEnabled() && !typeReg.isSet()) {
        /*
         * Test the result of this native against the known result type set for
         * the call. We don't assume knowledge about the types that natives can
         * return, except when generating specialized paths in FastBuiltins.
         */
        types::TypeSet *types = f.script()->analysis()->bytecodeTypes(f.pc());
        if (!masm.generateTypeCheck(f.cx, resultAddress, types, &mismatches))
            THROWV(false);
    }

    /*
     * Can no longer trigger recompilation in this stub, clear the stub rejoin
     * on the VMFrame.
     */
    masm.storePtr(ImmPtr(NULL), FrameAddress(offsetof(VMFrame, stubRejoin)));

    if (typeReg.isSet())
        masm.loadValueAsComponents(resultAddress, typeReg.reg(), dataReg.reg());

    /*
     * The final jump is a indirect on x64, so that we'll always be able
     * to repatch it to the interpoline later.
     */
    Label finished = masm.label();
#ifdef JS_CPU_X64
    JSC::MacroAssembler::DataLabelPtr done = masm.moveWithPatch(ImmPtr(NULL), Registers::ValueReg);
    masm.jump(Registers::ValueReg);
#else
    Jump done = masm.jump();
#endif

    /* Generate a call for type check failures on the native result. */
    if (!mismatches.empty()) {
        for (unsigned i = 0; i < mismatches.length(); i++)
            mismatches[i].linkTo(masm.label(), &masm);
        masm.addPtr(Imm32(vpOffset), JSFrameReg, Registers::ArgReg1);
        masm.fallibleVMCall(true, JS_FUNC_TO_DATA_PTR(void *, stubs::TypeBarrierReturn),
                            f.regs.pc, NULL, initialFrameDepth);
        masm.storePtr(ImmPtr(NULL), FrameAddress(offsetof(VMFrame, stubRejoin)));
        masm.jump().linkTo(finished, &masm);
    }

    /* Move JaegerThrowpoline into register for very far jump on x64. */
    hasException.linkTo(masm.label(), &masm);
    masm.storePtr(ImmPtr(NULL), FrameAddress(offsetof(VMFrame, stubRejoin)));
    masm.throwInJIT();

    *result = done;
    return true;
}

/*
 * Calls have an inline path and an out-of-line path. The inline path is used
 * in the fastest case: the method has JIT'd code, and |argc == nargs|.
 *
 * The inline path and OOL path are separated by a guard on the identity of
 * the callee object. This guard starts as NULL and always fails on the first
 * hit. On the OOL path, the callee is verified to be both a function and a
 * scripted function. If these conditions hold, |ic::Call| is invoked.
 *
 * |ic::Call| first ensures that the callee has JIT code. If it doesn't, the
 * call to |ic::Call| is patched to a slow path. If it does have JIT'd code,
 * the following cases can occur:
 *
 *   1) args != nargs: The call to |ic::Call| is patched with a dynamically
 *      generated stub. This stub inlines a path that looks like:
 *      ----
 *      push frame
 *      if (callee is not compiled) {
 *          Compile(callee);
 *      }
 *      call callee->arityLabel
 *
 *      The arity label is a special entry point for correcting frames for
 *      arity mismatches.
 *
 *   2) args == nargs, and the inline call site was not patched yet.
 *      The guard dividing the two paths is patched to guard on the given
 *      function object identity, and the proceeding call is patched to
 *      directly call the JIT code.
 *
 *   3) args == nargs, and the inline call site was patched already.
 *      A small stub is created which extends the original guard to also
 *      guard on the JSFunction lying underneath the function object.
 *
 * If the OOL path does not have a scripted function, but does have a
 * scripted native, then a small stub is generated which inlines the native
 * invocation.
 */
namespace js {
namespace mjit {

class CallCompiler : public BaseCompiler
{
    VMFrame &f;
    CallICInfo &ic;
    bool callingNew;

  public:
    CallCompiler(VMFrame &f, CallICInfo &ic, bool callingNew)
      : BaseCompiler(f.cx), f(f), ic(ic), callingNew(callingNew)
    {
    }

    JSC::ExecutablePool *poolForSize(LinkerHelper &linker, CallICInfo::PoolIndex index)
    {
        JSC::ExecutablePool *ep = linker.init(f.cx);
        if (!ep)
            return NULL;
        JS_ASSERT(!ic.pools[index]);
        ic.pools[index] = ep;
        return ep;
    }

    void disable()
    {
        JSC::CodeLocationCall oolCall = ic.slowPathStart.callAtOffset(ic.oolCallOffset);
        Repatcher repatch(f.chunk());
        JSC::FunctionPtr fptr = callingNew
                                ? JSC::FunctionPtr(JS_FUNC_TO_DATA_PTR(void *, SlowNewFromIC))
                                : JSC::FunctionPtr(JS_FUNC_TO_DATA_PTR(void *, SlowCallFromIC));
        repatch.relink(oolCall, fptr);
    }

    bool generateFullCallStub(JSScript *script, uint32_t flags)
    {
        /*
         * Create a stub that works with arity mismatches. Like the fast-path,
         * this allocates a frame on the caller side, but also performs extra
         * checks for compilability. Perhaps this should be a separate, shared
         * trampoline, but for now we generate it dynamically.
         */
        Assembler masm;
        InlineFrameAssembler inlFrame(masm, ic, flags);
        RegisterID t0 = inlFrame.tempRegs.takeAnyReg().reg();

        /* Generate the inline frame creation. */
        void *ncode = ic.funGuard.labelAtOffset(ic.joinPointOffset).executableAddress();
        inlFrame.assemble(ncode, f.pc());

        /* funObjReg is still valid. Check if a compilation is needed. */
        Address scriptAddr(ic.funObjReg, JSFunction::offsetOfNativeOrScript());
        masm.loadPtr(scriptAddr, t0);

        // Test that:
        // - script->mJITInfo is not NULL
        // - script->mJITInfo->jitHandle{Ctor,Normal}->value is neither NULL nor UNJITTABLE, and
        // - script->mJITInfo->jitHandle{Ctor,Normal}->value->arityCheckEntry is not NULL.
        masm.loadPtr(Address(t0, JSScript::offsetOfMJITInfo()), t0);
        Jump hasNoJitInfo = masm.branchPtr(Assembler::Equal, t0, ImmPtr(NULL));
        size_t offset = JSScript::JITScriptSet::jitHandleOffset(callingNew,
                                                                f.cx->compartment->compileBarriers());
        masm.loadPtr(Address(t0, offset), t0);
        Jump hasNoJitCode = masm.branchPtr(Assembler::BelowOrEqual, t0,
                                           ImmPtr(JSScript::JITScriptHandle::UNJITTABLE));

        masm.loadPtr(Address(t0, offsetof(JITScript, arityCheckEntry)), t0);

        Jump hasCode = masm.branchPtr(Assembler::NotEqual, t0, ImmPtr(0));

        hasNoJitInfo.linkTo(masm.label(), &masm);
        hasNoJitCode.linkTo(masm.label(), &masm);

        /*
         * Write the rejoin state to indicate this is a compilation call made
         * from an IC (the recompiler cannot detect calls made from ICs
         * automatically).
         */
        masm.storePtr(ImmPtr((void *) ic.frameSize.rejoinState(f.pc(), false)),
                      FrameAddress(offsetof(VMFrame, stubRejoin)));

        masm.bumpStubCount(f.script(), f.pc(), Registers::tempCallReg());

        /* Try and compile. On success we get back the nmap pointer. */
        void *compilePtr = JS_FUNC_TO_DATA_PTR(void *, stubs::CompileFunction);
        DataLabelPtr inlined;
        if (ic.frameSize.isStatic()) {
            masm.move(Imm32(ic.frameSize.staticArgc()), Registers::ArgReg1);
            masm.fallibleVMCall(cx->typeInferenceEnabled(),
                                compilePtr, f.regs.pc, &inlined, ic.frameSize.staticLocalSlots());
        } else {
            masm.load32(FrameAddress(VMFrame::offsetOfDynamicArgc()), Registers::ArgReg1);
            masm.fallibleVMCall(cx->typeInferenceEnabled(),
                                compilePtr, f.regs.pc, &inlined, -1);
        }

        Jump notCompiled = masm.branchTestPtr(Assembler::Zero, Registers::ReturnReg,
                                              Registers::ReturnReg);
        masm.loadPtr(FrameAddress(VMFrame::offsetOfRegsSp()), JSFrameReg);

        /* Compute the value of ncode to use at this call site. */
        ncode = (uint8_t *) f.chunk()->code.m_code.executableAddress() + ic.call->codeOffset;
        masm.storePtr(ImmPtr(ncode), Address(JSFrameReg, StackFrame::offsetOfNcode()));

        masm.jump(Registers::ReturnReg);

        hasCode.linkTo(masm.label(), &masm);

        /* Get nmap[ARITY], set argc, call. */
        if (ic.frameSize.isStatic())
            masm.move(Imm32(ic.frameSize.staticArgc()), JSParamReg_Argc);
        else
            masm.load32(FrameAddress(VMFrame::offsetOfDynamicArgc()), JSParamReg_Argc);
        masm.jump(t0);

        LinkerHelper linker(masm, JSC::METHOD_CODE);
        JSC::ExecutablePool *ep = poolForSize(linker, CallICInfo::Pool_ScriptStub);
        if (!ep)
            return false;

        if (!linker.verifyRange(f.chunk())) {
            disable();
            return true;
        }

        linker.link(notCompiled, ic.slowPathStart.labelAtOffset(ic.slowJoinOffset));
        JSC::CodeLocationLabel cs = linker.finalize(f);

        JaegerSpew(JSpew_PICs, "generated CALL stub %p (%lu bytes)\n", cs.executableAddress(),
                   (unsigned long) masm.size());

        if (f.regs.inlined()) {
            JSC::LinkBuffer code((uint8_t *) cs.executableAddress(), masm.size(), JSC::METHOD_CODE);
            code.patch(inlined, f.regs.inlined());
        }

        Repatcher repatch(f.chunk());
        JSC::CodeLocationJump oolJump = ic.slowPathStart.jumpAtOffset(ic.oolJumpOffset);
        repatch.relink(oolJump, cs);

        return true;
    }

    bool patchInlinePath(JSScript *script, JSObject *obj)
    {
        JS_ASSERT(ic.frameSize.isStatic());
        JITScript *jit = script->getJIT(callingNew, f.cx->compartment->compileBarriers());

        /* Very fast path. */
        Repatcher repatch(f.chunk());

        /*
         * Use the arguments check entry if this is a monitored call, we might
         * not have accounted for all possible argument types.
         */
        void *entry = ic.typeMonitored ? jit->argsCheckEntry : jit->fastEntry;

        if (!repatch.canRelink(ic.funGuard.jumpAtOffset(ic.hotJumpOffset),
                               JSC::CodeLocationLabel(entry))) {
            return false;
        }

        ic.fastGuardedObject = obj;
        JS_APPEND_LINK(&ic.links, &jit->callers);

        repatch.repatch(ic.funGuard, obj);
        repatch.relink(ic.funGuard.jumpAtOffset(ic.hotJumpOffset),
                       JSC::CodeLocationLabel(entry));

        JaegerSpew(JSpew_PICs, "patched CALL path %p (obj: %p)\n",
                   ic.funGuard.executableAddress(),
                   static_cast<void*>(ic.fastGuardedObject));

        return true;
    }

    bool generateStubForClosures(JSObject *obj)
    {
        JS_ASSERT(ic.frameSize.isStatic());

        /* Slightly less fast path - guard on fun->script() instead. */
        Assembler masm;

        Registers tempRegs(Registers::AvailRegs);
        tempRegs.takeReg(ic.funObjReg);

        RegisterID t0 = tempRegs.takeAnyReg().reg();

        /* Guard that it's actually a function object. */
        Jump claspGuard = masm.testObjClass(Assembler::NotEqual, ic.funObjReg, t0, &FunctionClass);

        /* Guard that it's the same script. */
        Address scriptAddr(ic.funObjReg, JSFunction::offsetOfNativeOrScript());
        Jump funGuard = masm.branchPtr(Assembler::NotEqual, scriptAddr,
                                       ImmPtr(obj->toFunction()->script()));
        Jump done = masm.jump();

        LinkerHelper linker(masm, JSC::METHOD_CODE);
        JSC::ExecutablePool *ep = poolForSize(linker, CallICInfo::Pool_ClosureStub);
        if (!ep)
            return false;

        ic.hasJsFunCheck = true;

        if (!linker.verifyRange(f.chunk())) {
            disable();
            return true;
        }

        linker.link(claspGuard, ic.slowPathStart);
        linker.link(funGuard, ic.slowPathStart);
        linker.link(done, ic.funGuard.labelAtOffset(ic.hotPathOffset));
        JSC::CodeLocationLabel cs = linker.finalize(f);

        JaegerSpew(JSpew_PICs, "generated CALL closure stub %p (%lu bytes)\n",
                   cs.executableAddress(), (unsigned long) masm.size());

        Repatcher repatch(f.chunk());
        repatch.relink(ic.funJump, cs);

        return true;
    }

    bool generateNativeStub()
    {
        /* Snapshot the frameDepth before SplatApplyArgs modifies it. */
        unsigned initialFrameDepth = f.regs.sp - f.fp()->slots();

        /* Protect against accessing the IC if it may have been purged. */
        RecompilationMonitor monitor(cx);

        /*
         * SplatApplyArgs has not been called, so we call it here before
         * potentially touching f.u.call.dynamicArgc.
         */
        CallArgs args;
        if (ic.frameSize.isStatic()) {
            JS_ASSERT(f.regs.sp - f.fp()->slots() == (int)ic.frameSize.staticLocalSlots());
            args = CallArgsFromSp(ic.frameSize.staticArgc(), f.regs.sp);
        } else {
            JS_ASSERT(!f.regs.inlined());
            JS_ASSERT(*f.regs.pc == JSOP_FUNAPPLY && GET_ARGC(f.regs.pc) == 2);
            /* Updates regs.sp -- may cause GC. */
            if (!ic::SplatApplyArgs(f))
                THROWV(true);
            args = CallArgsFromSp(f.u.call.dynamicArgc, f.regs.sp);
        }

        RootedFunction fun(cx);
        if (!IsFunctionObject(args.calleev(), fun.address()))
            return false;

        if ((!callingNew && !fun->isNative()) || (callingNew && !fun->isNativeConstructor()))
            return false;

        if (callingNew)
            args.setThis(MagicValue(JS_IS_CONSTRUCTING));

        if (!CallJSNative(cx, fun->native(), args))
            THROWV(true);

        types::TypeScript::Monitor(f.cx, f.script(), f.pc(), args.rval());

        /*
         * Native stubs are not generated for inline frames. The overhead of
         * bailing out from the IC is far greater than the time saved by
         * inlining the parent frame in the first place, so mark the immediate
         * caller as uninlineable.
         */
        if (f.script()->function()) {
            f.script()->uninlineable = true;
            MarkTypeObjectFlags(cx, f.script()->function(), types::OBJECT_FLAG_UNINLINEABLE);
        }

        /* Don't touch the IC if the call triggered a recompilation. */
        if (monitor.recompiled())
            return true;

        JS_ASSERT(!f.regs.inlined());

        /* Right now, take slow-path for IC misses or multiple stubs. */
        if (ic.fastGuardedNative || ic.hasJsFunCheck)
            return true;

        /* Native MIC needs to warm up first. */
        if (!ic.hit) {
            ic.hit = true;
            return true;
        }

        /* Generate fast-path for calling this native. */
        Assembler masm;

        /* Guard on the function object identity, for now. */
        Jump funGuard = masm.branchPtr(Assembler::NotEqual, ic.funObjReg, ImmPtr(fun));

        /*
         * Write the rejoin state for the recompiler to use if this call
         * triggers recompilation. Natives use a different stack address to
         * store the return value than FASTCALLs, and without additional
         * information we cannot tell which one is active on a VMFrame.
         */
        masm.storePtr(ImmPtr((void *) ic.frameSize.rejoinState(f.pc(), true)),
                      FrameAddress(offsetof(VMFrame, stubRejoin)));

        /* N.B. After this call, the frame will have a dynamic frame size. */
        if (ic.frameSize.isDynamic()) {
            masm.bumpStubCount(f.script(), f.pc(), Registers::tempCallReg());
            masm.fallibleVMCall(cx->typeInferenceEnabled(),
                                JS_FUNC_TO_DATA_PTR(void *, ic::SplatApplyArgs),
                                f.regs.pc, NULL, initialFrameDepth);
        }

        Registers tempRegs = Registers::tempCallRegMask();
        RegisterID t0 = tempRegs.takeAnyReg().reg();
        masm.bumpStubCount(f.script(), f.pc(), t0);

        int32_t storeFrameDepth = ic.frameSize.isStatic() ? initialFrameDepth : -1;
        masm.setupFallibleABICall(cx->typeInferenceEnabled(), f.regs.pc, storeFrameDepth);

        /* Grab cx. */
#ifdef JS_CPU_X86
        RegisterID cxReg = tempRegs.takeAnyReg().reg();
#else
        RegisterID cxReg = Registers::ArgReg0;
#endif
        masm.loadPtr(FrameAddress(offsetof(VMFrame, cx)), cxReg);

        /*
         * Compute vp. This will always be at the same offset from fp for a
         * given callsite, regardless of any dynamically computed argc,
         * so get that offset from the active call.
         */
#ifdef JS_CPU_X86
        RegisterID vpReg = t0;
#else
        RegisterID vpReg = Registers::ArgReg2;
#endif
        uint32_t vpOffset = (uint32_t) ((char *) args.base() - (char *) f.fp());
        masm.addPtr(Imm32(vpOffset), JSFrameReg, vpReg);

        /* Compute argc. */
        MaybeRegisterID argcReg;
        if (!ic.frameSize.isStatic()) {
            argcReg = tempRegs.takeAnyReg().reg();
            masm.load32(FrameAddress(VMFrame::offsetOfDynamicArgc()), argcReg.reg());
        }

        /* Mark vp[1] as magic for |new|. */
        if (callingNew)
            masm.storeValue(MagicValue(JS_IS_CONSTRUCTING), Address(vpReg, sizeof(Value)));

        masm.restoreStackBase();
        masm.setupABICall(Registers::NormalCall, 3);
        masm.storeArg(2, vpReg);
        if (ic.frameSize.isStatic())
            masm.storeArg(1, ImmIntPtr(intptr_t(ic.frameSize.staticArgc())));
        else
            masm.storeArg(1, argcReg.reg());
        masm.storeArg(0, cxReg);

        js::Native native = fun->native();

        /*
         * Call RegExp.test instead of exec if the result will not be used or
         * will only be used to test for existence. Note that this will not
         * break inferred types for the call's result and any subsequent test,
         * as RegExp.exec has a type handler with unknown result.
         */
        if (native == regexp_exec && !CallResultEscapes(f.pc()))
            native = regexp_test;

        masm.callWithABI(JS_FUNC_TO_DATA_PTR(void *, native), false);

        NativeStubLinker::FinalJump done;
        if (!NativeStubEpilogue(f, masm, &done, initialFrameDepth, vpOffset, MaybeRegisterID(), MaybeRegisterID()))
            return false;
        NativeStubLinker linker(masm, f.chunk(), f.regs.pc, done);
        if (!linker.init(f.cx))
            THROWV(true);

        if (!linker.verifyRange(f.chunk())) {
            disable();
            return true;
        }

        linker.patchJump(ic.slowPathStart.labelAtOffset(ic.slowJoinOffset));

        ic.fastGuardedNative = fun;

        linker.link(funGuard, ic.slowPathStart);
        JSC::CodeLocationLabel start = linker.finalize(f);

        JaegerSpew(JSpew_PICs, "generated native CALL stub %p (%lu bytes)\n",
                   start.executableAddress(), (unsigned long) masm.size());

        Repatcher repatch(f.chunk());
        repatch.relink(ic.funJump, start);

        return true;
    }

    void *update()
    {
        RecompilationMonitor monitor(cx);

        bool lowered = ic.frameSize.lowered(f.pc());
        JS_ASSERT_IF(lowered, !callingNew);

        StackFrame *initialFp = f.fp();

        stubs::UncachedCallResult ucr;
        if (callingNew)
            stubs::UncachedNewHelper(f, ic.frameSize.staticArgc(), &ucr);
        else
            stubs::UncachedCallHelper(f, ic.frameSize.getArgc(f), lowered, &ucr);

        // Watch out in case the IC was invalidated by a recompilation on the calling
        // script. This can happen either if the callee is executed or if it compiles
        // and the compilation has a static overflow. Also watch for cases where
        // an exception is thrown and the callee frame hasn't unwound yet.
        if (monitor.recompiled() || f.fp() != initialFp)
            return ucr.codeAddr;

        // If the function cannot be jitted (generally unjittable or empty script),
        // patch this site to go to a slow path always.
        if (!ucr.codeAddr) {
            if (ucr.unjittable)
                disable();
            return NULL;
        }

        JSFunction *fun = ucr.fun;
        JS_ASSERT(fun);
        JSScript *script = fun->script();
        JS_ASSERT(script);

        uint32_t flags = callingNew ? StackFrame::CONSTRUCTING : 0;

        if (!ic.hit) {
            ic.hit = true;
            return ucr.codeAddr;
        }

        if (!ic.frameSize.isStatic() || ic.frameSize.staticArgc() != fun->nargs) {
            if (!generateFullCallStub(script, flags))
                THROWV(NULL);
        } else {
            if (!ic.fastGuardedObject && patchInlinePath(script, fun)) {
                // Nothing, done.
            } else if (ic.fastGuardedObject &&
                       !ic.hasJsFunCheck &&
                       !ic.fastGuardedNative &&
                       ic.fastGuardedObject->toFunction()->script() == fun->script()) {
                /*
                 * Note: Multiple "function guard" stubs are not yet
                 * supported, thus the fastGuardedNative check.
                 */
                if (!generateStubForClosures(fun))
                    THROWV(NULL);
            } else {
                if (!generateFullCallStub(script, flags))
                    THROWV(NULL);
            }
        }

        return ucr.codeAddr;
    }
};

} // namespace mjit
} // namespace js

void * JS_FASTCALL
ic::Call(VMFrame &f, CallICInfo *ic)
{
    CallCompiler cc(f, *ic, false);
    return cc.update();
}

void * JS_FASTCALL
ic::New(VMFrame &f, CallICInfo *ic)
{
    CallCompiler cc(f, *ic, true);
    return cc.update();
}

void * JS_FASTCALL
ic::NativeCall(VMFrame &f, CallICInfo *ic)
{
    CallCompiler cc(f, *ic, false);
    if (!cc.generateNativeStub())
        stubs::SlowCall(f, ic->frameSize.getArgc(f));
    return NULL;
}

void * JS_FASTCALL
ic::NativeNew(VMFrame &f, CallICInfo *ic)
{
    CallCompiler cc(f, *ic, true);
    if (!cc.generateNativeStub())
        stubs::SlowNew(f, ic->frameSize.staticArgc());
    return NULL;
}

static JS_ALWAYS_INLINE bool
BumpStack(VMFrame &f, unsigned inc)
{
    if (f.regs.sp + inc < f.stackLimit)
        return true;
    return f.cx->stack.space().tryBumpLimit(f.cx, f.regs.sp, inc, &f.stackLimit);
}

/*
 * SplatApplyArgs is only called for expressions of the form |f.apply(x, y)|.
 * Additionally, the callee has already been checked to be the native apply.
 * All successful paths through SplatApplyArgs must set f.u.call.dynamicArgc
 * and f.regs.sp.
 */
JSBool JS_FASTCALL
ic::SplatApplyArgs(VMFrame &f)
{
    JSContext *cx = f.cx;
    JS_ASSERT(!f.regs.inlined());

    CallArgs args = CallArgsFromSp(GET_ARGC(f.regs.pc), f.regs.sp);
    JS_ASSERT(args.length() == 2);
    JS_ASSERT(IsNativeFunction(args.calleev(), js_fun_apply));

    if (IsOptimizedArguments(f.fp(), &args[1])) {
        /* Mirror isMagic(JS_OPTIMIZED_ARGUMENTS) case in js_fun_apply. */
        /* Steps 4-6. */
        unsigned length = f.regs.fp()->numActualArgs();
        JS_ASSERT(length <= StackSpace::ARGS_LENGTH_MAX);

        f.regs.sp--;
        if (!BumpStack(f, length))
            THROWV(false);

        /* Steps 7-8. */
        f.regs.fp()->forEachUnaliasedActual(CopyTo(f.regs.sp));

        f.regs.sp += length;
        f.u.call.dynamicArgc = length;
        return true;
    }

    /*
     * This stub should mimic the steps taken by js_fun_apply. Step 1 and part
     * of Step 2 have already been taken care of by calling jit code.
     */

    /* Step 2 (part 2). */
    if (args[1].isNullOrUndefined()) {
        f.regs.sp--;
        f.u.call.dynamicArgc = 0;
        return true;
    }

    /* Step 3. */
    if (!args[1].isObject()) {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_BAD_APPLY_ARGS, js_apply_str);
        THROWV(false);
    }

    /* Steps 4-5. */
    RootedObject aobj(cx, &args[1].toObject());
    uint32_t length;
    if (!GetLengthProperty(cx, aobj, &length))
        THROWV(false);

    /* Step 6. */
    if (length > StackSpace::ARGS_LENGTH_MAX) {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                             JSMSG_TOO_MANY_FUN_APPLY_ARGS);
        THROWV(false);
    }

    int delta = length - 1;
    if (delta > 0) {
        if (!BumpStack(f, delta))
            THROWV(false);

        MakeRangeGCSafe(f.regs.sp, delta);
    }

    f.regs.sp += delta;

    /* Steps 7-8. */
    if (!GetElements(cx, aobj, length, f.regs.sp - length))
        THROWV(false);

    f.u.call.dynamicArgc = length;
    return true;
}

void
ic::GenerateArgumentCheckStub(VMFrame &f)
{
    JS_ASSERT(f.cx->typeInferenceEnabled());

    JITScript *jit = f.jit();
    StackFrame *fp = f.fp();
    JSFunction *fun = fp->fun();
    JSScript *script = fun->script();

    if (jit->argsCheckPool)
        jit->resetArgsCheck();

    Assembler masm;
    Vector<Jump> mismatches(f.cx);

    if (!f.fp()->isConstructing()) {
        types::TypeSet *types = types::TypeScript::ThisTypes(script);
        Address address(JSFrameReg, StackFrame::offsetOfThis(fun));
        if (!masm.generateTypeCheck(f.cx, address, types, &mismatches))
            return;
    }

    for (unsigned i = 0; i < fun->nargs; i++) {
        types::TypeSet *types = types::TypeScript::ArgTypes(script, i);
        Address address(JSFrameReg, StackFrame::offsetOfFormalArg(fun, i));
        if (!masm.generateTypeCheck(f.cx, address, types, &mismatches))
            return;
    }

    Jump done = masm.jump();

    LinkerHelper linker(masm, JSC::METHOD_CODE);
    JSC::ExecutablePool *ep = linker.init(f.cx);
    if (!ep)
        return;
    jit->argsCheckPool = ep;

    if (!linker.verifyRange(f.chunk())) {
        jit->resetArgsCheck();
        return;
    }

    for (unsigned i = 0; i < mismatches.length(); i++)
        linker.link(mismatches[i], jit->argsCheckStub);
    linker.link(done, jit->argsCheckFallthrough);

    JSC::CodeLocationLabel cs = linker.finalize(f);

    JaegerSpew(JSpew_PICs, "generated ARGS CHECK stub %p (%lu bytes)\n",
               cs.executableAddress(), (unsigned long)masm.size());

    Repatcher repatch(f.chunk());
    repatch.relink(jit->argsCheckJump, cs);
}

void
JITScript::resetArgsCheck()
{
    argsCheckPool->release();
    argsCheckPool = NULL;

    Repatcher repatch(chunk(script->code));
    repatch.relink(argsCheckJump, argsCheckStub);
}

#endif /* JS_MONOIC */