C++ VMFrame::fp方法代码示例

void JS_FASTCALL
stubs::CreateFunCallObject(VMFrame &f)
{
    JS_ASSERT(f.fp()->fun()->isHeavyweight());
    if (!js::CreateFunCallObject(f.cx, f.fp()))
        THROW();
}

/*
 * Clean up a frame and return.
 */
static void
InlineReturn(VMFrame &f)
{
    JS_ASSERT(f.fp() != f.entryfp);
    JS_ASSERT(!js_IsActiveWithOrBlock(f.cx, &f.fp()->scopeChain(), 0));
    f.cx->stack.popInlineFrame(f.regs);
}

static void
FinishVarIncOp(VMFrame &f, RejoinState rejoin, Value ov, Value nv, Value *vp)
{
    /* Finish an increment operation on a LOCAL or ARG. These do not involve property accesses. */
    JS_ASSERT(rejoin == REJOIN_POS || rejoin == REJOIN_BINARY);

    JSContext *cx = f.cx;

    JSOp op = JSOp(*f.pc());
    JS_ASSERT(op == JSOP_LOCALINC || op == JSOP_INCLOCAL ||
              op == JSOP_LOCALDEC || op == JSOP_DECLOCAL ||
              op == JSOP_ARGINC || op == JSOP_INCARG ||
              op == JSOP_ARGDEC || op == JSOP_DECARG);
    const JSCodeSpec *cs = &js_CodeSpec[op];

    if (rejoin == REJOIN_POS) {
        double d = ov.toNumber();
        double N = (cs->format & JOF_INC) ? 1 : -1;
        if (!nv.setNumber(d + N)) {
            RootedScript fscript(cx, f.script());
            types::TypeScript::MonitorOverflow(cx, fscript, f.pc());
        }
    }

    unsigned i = GET_SLOTNO(f.pc());
    if (JOF_TYPE(cs->format) == JOF_LOCAL)
        f.fp()->unaliasedLocal(i) = nv;
    else if (f.fp()->script()->argsObjAliasesFormals())
        f.fp()->argsObj().setArg(i, nv);
    else
        f.fp()->unaliasedFormal(i) = nv;

    *vp = (cs->format & JOF_POST) ? ov : nv;
}

void JS_FASTCALL
stubs::PutStrictEvalCallObject(VMFrame &f)
{
    JS_ASSERT(f.fp()->isEvalFrame());
    JS_ASSERT(f.fp()->script()->strictModeCode);
    JS_ASSERT(f.fp()->hasCallObj());
    js_PutCallObject(f.cx, f.fp());
}

/*
 * Clean up a frame and return.
 */
static void
InlineReturn(VMFrame &f)
{
    JS_ASSERT(f.fp() != f.entryfp);
    JS_ASSERT(!js_IsActiveWithOrBlock(f.cx, &f.fp()->scopeChain(), 0));
    f.cx->stack.popInlineFrame(f.regs);

    JS_ASSERT(*f.regs.pc == JSOP_CALL ||
              *f.regs.pc == JSOP_NEW ||
              *f.regs.pc == JSOP_EVAL ||
              *f.regs.pc == JSOP_FUNCALL ||
              *f.regs.pc == JSOP_FUNAPPLY);
    f.regs.pc += JSOP_CALL_LENGTH;
}

/*
 * HitStackQuota is called after the early prologue pushing the new frame would
 * overflow f.stackLimit.
 */
void JS_FASTCALL
stubs::HitStackQuota(VMFrame &f)
{
    /* Include space to push another frame. */
    uintN nvals = f.fp()->script()->nslots + VALUES_PER_STACK_FRAME;
    JS_ASSERT(f.regs.sp == f.fp()->base());
    if (f.cx->stack().bumpCommitAndLimit(f.entryfp, f.regs.sp, nvals, &f.stackLimit))
        return;

    /* Remove the current partially-constructed frame before throwing. */
    RemovePartialFrame(f.cx, f.fp());
    js_ReportOverRecursed(f.cx);
    THROW();
}

void JS_FASTCALL
ic::GetGlobalName(VMFrame &f, ic::GetGlobalNameIC *ic)
{
    JSObject *obj = f.fp()->scopeChain().getGlobal();
    JSAtom *atom = f.script()->getAtom(GET_INDEX(f.pc()));
    jsid id = ATOM_TO_JSID(atom);

    const Shape *shape = obj->nativeLookup(f.cx, id);
    if (!shape ||
        !shape->hasDefaultGetterOrIsMethod() ||
        !shape->hasSlot())
    {
        if (shape)
            PatchGetFallback(f, ic);
        stubs::GetGlobalName(f);
        return;
    }
    uint32 slot = shape->slot;

    /* Patch shape guard. */
    Repatcher repatcher(f.jit());
    repatcher.repatch(ic->fastPathStart.dataLabel32AtOffset(ic->shapeOffset), obj->shape());

    /* Patch loads. */
    uint32 index = obj->dynamicSlotIndex(slot);
    JSC::CodeLocationLabel label = ic->fastPathStart.labelAtOffset(ic->loadStoreOffset);
    repatcher.patchAddressOffsetForValueLoad(label, index * sizeof(Value));

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

/*
 * Clean up a frame and return.
 */
static void
InlineReturn(VMFrame &f)
{
    JS_ASSERT(f.fp() != f.entryfp);
    JS_ASSERT(!IsActiveWithOrBlock(f.cx, f.fp()->scopeChain(), 0));
    JS_ASSERT(!f.fp()->hasBlockChain());
    f.cx->stack.popInlineFrame(f.regs);

    DebugOnly<JSOp> op = JSOp(*f.regs.pc);
    JS_ASSERT(op == JSOP_CALL ||
              op == JSOP_NEW ||
              op == JSOP_EVAL ||
              op == JSOP_FUNCALL ||
              op == JSOP_FUNAPPLY);
    f.regs.pc += JSOP_CALL_LENGTH;
}

void JS_FASTCALL
stubs::Eval(VMFrame &f, uint32 argc)
{
    CallArgs args = CallArgsFromSp(argc, f.regs.sp);

    if (!IsBuiltinEvalForScope(&f.fp()->scopeChain(), args.calleev())) {
        if (!Invoke(f.cx, args))
            THROW();
        return;
    }

    JS_ASSERT(f.fp() == f.cx->fp());
    if (!DirectEval(f.cx, args))
        THROW();

    f.regs.sp = args.spAfterCall();
}

void JS_FASTCALL
stubs::BindName(VMFrame &f, PropertyName *name_)
{
    RootedPropertyName name(f.cx, name_);
    RootedObject scope(f.cx);
    if (!LookupNameWithGlobalDefault(f.cx, name, f.fp()->scopeChain(), &scope))
        THROW();
    f.regs.sp[0].setObject(*scope);
}

/*
 * This function must only be called after the early prologue, since it depends
 * on fp->exec.fun.
 */
void * JS_FASTCALL
stubs::FixupArity(VMFrame &f, uint32 nactual)
{
    JSContext *cx = f.cx;
    JSStackFrame *oldfp = f.fp();

    JS_ASSERT(nactual != oldfp->numFormalArgs());

    /*
     * Grossssss! *move* the stack frame. If this ends up being perf-critical,
     * we can figure out how to spot-optimize it. Be careful to touch only the
     * members that have been initialized by initCallFrameCallerHalf and the
     * early prologue.
     */
    uint32 flags         = oldfp->isConstructingFlag();
    JSFunction *fun      = oldfp->fun();
    void *ncode          = oldfp->nativeReturnAddress();

    /* Pop the inline frame. */
    f.fp() = oldfp->prev();
    f.regs.sp = (Value*) oldfp;

    /* Reserve enough space for a callee frame. */
    JSStackFrame *newfp = cx->stack().getInlineFrameWithinLimit(cx, (Value*) oldfp, nactual,
                                                                fun, fun->script(), &flags,
                                                                f.entryfp, &f.stackLimit);
    if (!newfp) {
        /*
         * The PC is not coherent with the current frame, so fix it up for
         * exception handling.
         */
        f.regs.pc = f.jit()->nativeToPC(ncode);
        THROWV(NULL);
    }

    /* Reset the part of the stack frame set by the caller. */
    newfp->initCallFrameCallerHalf(cx, flags, ncode);

    /* Reset the part of the stack frame set by the prologue up to now. */
    newfp->initCallFrameEarlyPrologue(fun, nactual);

    /* The caller takes care of assigning fp to regs. */
    return newfp;
}

void JS_FASTCALL
stubs::CreateThis(VMFrame &f, JSObject *proto)
{
    JSContext *cx = f.cx;
    StackFrame *fp = f.fp();
    RootedObject callee(cx, &fp->callee());
    JSObject *obj = js_CreateThisForFunctionWithProto(cx, callee, proto);
    if (!obj)
        THROW();
    fp->thisValue() = ObjectValue(*obj);
}

void * JS_FASTCALL
stubs::CompileFunction(VMFrame &f, uint32_t argc)
{
    /*
     * Note: the stubRejoin kind for the frame was written before the call, and
     * needs to be cleared out on all return paths (doing this directly in the
     * IC stub will not handle cases where we recompiled or threw).
     */
    JS_ASSERT_IF(f.cx->typeInferenceEnabled(), f.stubRejoin);
    ResetStubRejoin reset(f);

    InitialFrameFlags initial = f.fp()->initialFlags();
    f.regs.popPartialFrame((Value *)f.fp());

    if (InitialFrameFlagsAreConstructing(initial))
        return UncachedNew(f, argc);
    else if (InitialFrameFlagsAreLowered(initial))
        return UncachedLoweredCall(f, argc);
    else
        return UncachedCall(f, argc);
}

/*
 * Clean up a frame and return.
 */
static void
InlineReturn(VMFrame &f)
{
    JSContext *cx = f.cx;
    JSStackFrame *fp = f.regs.fp;

    JS_ASSERT(f.fp() != f.entryfp);

    JS_ASSERT(!js_IsActiveWithOrBlock(cx, &fp->scopeChain(), 0));

    Value *newsp = fp->actualArgs() - 1;
    newsp[-1] = fp->returnValue();
    cx->stack().popInlineFrame(cx, fp->prev(), newsp);
}

void JS_FASTCALL
ic::SetGlobalName(VMFrame &f, ic::SetGlobalNameIC *ic)
{
    JSObject *obj = f.fp()->scopeChain().getGlobal();
    JSScript *script = f.script();
    JSAtom *atom = script->getAtom(GET_INDEX(f.pc()));
    const Shape *shape = obj->nativeLookup(f.cx, ATOM_TO_JSID(atom));

    LookupStatus status = UpdateSetGlobalName(f, ic, obj, shape);
    if (status == Lookup_Error)
        THROW();

    if (ic->usePropertyCache)
        STRICT_VARIANT(stubs::SetGlobalName)(f, atom);
    else
        STRICT_VARIANT(stubs::SetGlobalNameNoCache)(f, atom);
}