jitstubs.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

            // by the caller is null, the global object should be used. It also says
            // that the section does not apply to internal functions, but for simplicity
            // of implementation we use the global object anyway here. This guarantees
            // that in host objects you always get a valid object for this.
            // We also handle wrapper substitution for the global object at the same time.
            JSObject* thisObj = base->toThisObject(callFrame);
            JSValuePtr result = slot.getValue(callFrame, ident);
            CHECK_FOR_EXCEPTION_AT_END();

            RETURN_PAIR(thisObj, JSValuePtr::encode(result));
        }
        ++iter;
    } while (iter != end);

    CodeBlock* codeBlock = callFrame->codeBlock();
    unsigned vPCIndex = codeBlock->getBytecodeIndex(callFrame, STUB_RETURN_ADDRESS);
    ARG_globalData->exception = createUndefinedVariableError(callFrame, ident, vPCIndex, codeBlock);
    VM_THROW_EXCEPTION_2();
}

JSValueEncodedAsPointer* JITStubs::cti_op_sub(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr src1 = ARG_src1;
    JSValuePtr src2 = ARG_src2;

    double left;
    double right;
    if (src1.getNumber(left) && src2.getNumber(right))
        return JSValuePtr::encode(jsNumber(ARG_globalData, left - right));

    CallFrame* callFrame = ARG_callFrame;
    JSValuePtr result = jsNumber(ARG_globalData, src1.toNumber(callFrame) - src2.toNumber(callFrame));
    CHECK_FOR_EXCEPTION_AT_END();
    return JSValuePtr::encode(result);
}

void JITStubs::cti_op_put_by_val(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    CallFrame* callFrame = ARG_callFrame;
    JSGlobalData* globalData = ARG_globalData;

    JSValuePtr baseValue = ARG_src1;
    JSValuePtr subscript = ARG_src2;
    JSValuePtr value = ARG_src3;

    if (LIKELY(subscript.isUInt32Fast())) {
        uint32_t i = subscript.getUInt32Fast();
        if (isJSArray(globalData, baseValue)) {
            JSArray* jsArray = asArray(baseValue);
            if (jsArray->canSetIndex(i))
                jsArray->setIndex(i, value);
            else
                jsArray->JSArray::put(callFrame, i, value);
        } else if (isJSByteArray(globalData, baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
            JSByteArray* jsByteArray = asByteArray(baseValue);
            ctiPatchCallByReturnAddress(STUB_RETURN_ADDRESS, reinterpret_cast<void*>(cti_op_put_by_val_byte_array));
            // All fast byte array accesses are safe from exceptions so return immediately to avoid exception checks.
            if (value.isInt32Fast()) {
                jsByteArray->setIndex(i, value.getInt32Fast());
                return;
            } else {
                double dValue = 0;
                if (value.getNumber(dValue)) {
                    jsByteArray->setIndex(i, dValue);
                    return;
                }
            }

            baseValue.put(callFrame, i, value);
        } else
            baseValue.put(callFrame, i, value);
    } else {
        Identifier property(callFrame, subscript.toString(callFrame));
        if (!ARG_globalData->exception) { // Don't put to an object if toString threw an exception.
            PutPropertySlot slot;
            baseValue.put(callFrame, property, value, slot);
        }
    }

    CHECK_FOR_EXCEPTION_AT_END();
}

void JITStubs::cti_op_put_by_val_array(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    CallFrame* callFrame = ARG_callFrame;
    JSValuePtr baseValue = ARG_src1;
    int i = ARG_int2;
    JSValuePtr value = ARG_src3;

    ASSERT(isJSArray(ARG_globalData, baseValue));

    if (LIKELY(i >= 0))
        asArray(baseValue)->JSArray::put(callFrame, i, value);
    else {
        // This should work since we're re-boxing an immediate unboxed in JIT code.
        ASSERT(JSValuePtr::makeInt32Fast(i));
        Identifier property(callFrame, JSValuePtr::makeInt32Fast(i).toString(callFrame));
        // FIXME: can toString throw an exception here?
        if (!ARG_globalData->exception) { // Don't put to an object if toString threw an exception.
            PutPropertySlot slot;
            baseValue.put(callFrame, property, value, slot);
        }
    }

    CHECK_FOR_EXCEPTION_AT_END();
}

void JITStubs::cti_op_put_by_val_byte_array(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();
    
    CallFrame* callFrame = ARG_callFrame;
    JSGlobalData* globalData = ARG_globalData;
    
    JSValuePtr baseValue = ARG_src1;
    JSValuePtr subscript = ARG_src2;
    JSValuePtr value = ARG_src3;
    
    if (LIKELY(subscript.isUInt32Fast())) {
        uint32_t i = subscript.getUInt32Fast();
        if (isJSByteArray(globalData, baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
            JSByteArray* jsByteArray = asByteArray(baseValue);
            
            // All fast byte array accesses are safe from exceptions so return immediately to avoid exception checks.
            if (value.isInt32Fast()) {
                jsByteArray->setIndex(i, value.getInt32Fast());
                return;
            } else {
                double dValue = 0;                
                if (value.getNumber(dValue)) {
                    jsByteArray->setIndex(i, dValue);
                    return;
                }
            }
        }

        if (!isJSByteArray(globalData, baseValue))
            ctiPatchCallByReturnAddress(STUB_RETURN_ADDRESS, reinterpret_cast<void*>(cti_op_put_by_val));
        baseValue.put(callFrame, i, value);
    } else {
        Identifier property(callFrame, subscript.toString(callFrame));
        if (!ARG_globalData->exception) { // Don't put to an object if toString threw an exception.
            PutPropertySlot slot;
            baseValue.put(callFrame, property, value, slot);
        }
    }
    
    CHECK_FOR_EXCEPTION_AT_END();
}

JSValueEncodedAsPointer* JITStubs::cti_op_lesseq(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    CallFrame* callFrame = ARG_callFrame;
    JSValuePtr result = jsBoolean(jsLessEq(callFrame, ARG_src1, ARG_src2));
    CHECK_FOR_EXCEPTION_AT_END();
    return JSValuePtr::encode(result);
}

int JITStubs::cti_op_loop_if_true(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr src1 = ARG_src1;

    CallFrame* callFrame = ARG_callFrame;

    bool result = src1.toBoolean(callFrame);
    CHECK_FOR_EXCEPTION_AT_END();
    return result;
}

JSValueEncodedAsPointer* JITStubs::cti_op_negate(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr src = ARG_src1;

    double v;
    if (src.getNumber(v))
        return JSValuePtr::encode(jsNumber(ARG_globalData, -v));

    CallFrame* callFrame = ARG_callFrame;
    JSValuePtr result = jsNumber(ARG_globalData, -src.toNumber(callFrame));
    CHECK_FOR_EXCEPTION_AT_END();
    return JSValuePtr::encode(result);
}

JSValueEncodedAsPointer* JITStubs::cti_op_resolve_base(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    return JSValuePtr::encode(JSC::resolveBase(ARG_callFrame, *ARG_id1, ARG_callFrame->scopeChain()));
}

JSValueEncodedAsPointer* JITStubs::cti_op_resolve_skip(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    CallFrame* callFrame = ARG_callFrame;
    ScopeChainNode* scopeChain = callFrame->scopeChain();

    int skip = ARG_int2;

    ScopeChainIterator iter = scopeChain->begin();
    ScopeChainIterator end = scopeChain->end();
    ASSERT(iter != end);
    while (skip--) {
        ++iter;
        ASSERT(iter != end);
    }
    Identifier& ident = *ARG_id1;
    do {
        JSObject* o = *iter;
        PropertySlot slot(o);
        if (o->getPropertySlot(callFrame, ident, slot)) {
            JSValuePtr result = slot.getValue(callFrame, ident);
            CHECK_FOR_EXCEPTION_AT_END();
            return JSValuePtr::encode(result);
        }
    } while (++iter != end);

    CodeBlock* codeBlock = callFrame->codeBlock();
    unsigned vPCIndex = codeBlock->getBytecodeIndex(callFrame, STUB_RETURN_ADDRESS);
    ARG_globalData->exception = createUndefinedVariableError(callFrame, ident, vPCIndex, codeBlock);
    VM_THROW_EXCEPTION();
}

JSValueEncodedAsPointer* JITStubs::cti_op_resolve_global(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    CallFrame* callFrame = ARG_callFrame;
    JSGlobalObject* globalObject = asGlobalObject(ARG_src1);
    Identifier& ident = *ARG_id2;
    unsigned globalResolveInfoIndex = ARG_int3;
    ASSERT(globalObject->isGlobalObject());

    PropertySlot slot(globalObject);
    if (globalObject->getPropertySlot(callFrame, ident, slot)) {
        JSValuePtr result = slot.getValue(callFrame, ident);
        if (slot.isCacheable() && !globalObject->structure()->isDictionary()) {
            GlobalResolveInfo& globalResolveInfo = callFrame->codeBlock()->globalResolveInfo(globalResolveInfoIndex);
            if (globalResolveInfo.structure)
                globalResolveInfo.structure->deref();
            globalObject->structure()->ref();
            globalResolveInfo.structure = globalObject->structure();
            globalResolveInfo.offset = slot.cachedOffset();
            return JSValuePtr::encode(result);
        }

        CHECK_FOR_EXCEPTION_AT_END();
        return JSValuePtr::encode(result);
    }

    unsigned vPCIndex = callFrame->codeBlock()->getBytecodeIndex(callFrame, STUB_RETURN_ADDRESS);
    ARG_globalData->exception = createUndefinedVariableError(callFrame, ident, vPCIndex, callFrame->codeBlock());
    VM_THROW_EXCEPTION();
}

JSValueEncodedAsPointer* JITStubs::cti_op_div(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr src1 = ARG_src1;
    JSValuePtr src2 = ARG_src2;

    double left;
    double right;
    if (src1.getNumber(left) && src2.getNumber(right))
        return JSValuePtr::encode(jsNumber(ARG_globalData, left / right));

    CallFrame* callFrame = ARG_callFrame;
    JSValuePtr result = jsNumber(ARG_globalData, src1.toNumber(callFrame) / src2.toNumber(callFrame));
    CHECK_FOR_EXCEPTION_AT_END();
    return JSValuePtr::encode(result);
}

JSValueEncodedAsPointer* JITStubs::cti_op_pre_dec(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr v = ARG_src1;

    CallFrame* callFrame = ARG_callFrame;
    JSValuePtr result = jsNumber(ARG_globalData, v.toNumber(callFrame) - 1);
    CHECK_FOR_EXCEPTION_AT_END();
    return JSValuePtr::encode(result);
}

int JITStubs::cti_op_jless(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr src1 = ARG_src1;
    JSValuePtr src2 = ARG_src2;
    CallFrame* callFrame = ARG_callFrame;

    bool result = jsLess(callFrame, src1, src2);
    CHECK_FOR_EXCEPTION_AT_END();
    return result;
}

JSValueEncodedAsPointer* JITStubs::cti_op_not(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr src = ARG_src1;

    CallFrame* callFrame = ARG_callFrame;

    JSValuePtr result = jsBoolean(!src.toBoolean(callFrame));
    CHECK_FOR_EXCEPTION_AT_END();
    return JSValuePtr::encode(result);
}

int JITStubs::cti_op_jtrue(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr src1 = ARG_src1;

    CallFrame* callFrame = ARG_callFrame;

    bool result = src1.toBoolean(callFrame);
    CHECK_FOR_EXCEPTION_AT_END();
    return result;
}

VoidPtrPair JITStubs::cti_op_post_inc(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr v = ARG_src1;

    CallFrame* callFrame = ARG_callFrame;

    JSValuePtr number = v.toJSNumber(callFrame);
    CHECK_FOR_EXCEPTION_AT_END();

    RETURN_PAIR(JSValuePtr::encode(number), JSValuePtr::encode(jsNumber(ARG_globalData, number.uncheckedGetNumber() + 1)));
}

JSValueEncodedAsPointer* JITStubs::cti_op_eq(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr src1 = ARG_src1;
    JSValuePtr src2 = ARG_src2;

    CallFrame* callFrame = ARG_callFrame;

    ASSERT(!JSValuePtr::areBothInt32Fast(src1, src2));
    JSValuePtr result = jsBoolean(JSValuePtr::equalSlowCaseInline(callFrame, src1, src2));
    CHECK_FOR_EXCEPTION_AT_END();
    return JSValuePtr::encode(result);
}

JSValueEncodedAsPointer* JITStubs::cti_op_lshift(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr val = ARG_src1;
    JSValuePtr shift = ARG_src2;

    int32_t left;
    uint32_t right;
    if (JSValuePtr::areBothInt32Fast(val, shift))
        return JSValuePtr::encode(jsNumber(ARG_globalData, val.getInt32Fast() << (shift.getInt32Fast() & 0x1f)));
    if (val.numberToInt32(left) && shift.numberToUInt32(right))
        return JSValuePtr::encode(jsNumber(ARG_globalData, left << (right & 0x1f)));

    CallFrame* callFrame = ARG_callFrame;
    JSValuePtr result = jsNumber(ARG_globalData, (val.toInt32(callFrame)) << (shift.toUInt32(callFrame) & 0x1f));
    CHECK_FOR_EXCEPTION_AT_END();
    return JSValuePtr::encode(result);
}

JSValueEncodedAsPointer* JITStubs::cti_op_bitand(STUB_ARGS)
{
    BEGIN_STUB_FUNCTION();

    JSValuePtr src1 = ARG_src1;
    JSValuePtr src2 = ARG_src2;

    int32_t left;
    int32_t right;
    if (src1.numberToInt32(left) && src2.numberToInt32(right))
        return JSValuePtr::encode(jsNumber(ARG_globalData, left & right));

    CallFrame* callFrame = ARG_callFrame;