bytecodegenerator.cpp

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    return result.first->second;
}

RegisterID* BytecodeGenerator::addConstant(JSValuePtr v)
{
    pair<JSValueMap::iterator, bool> result = m_jsValueMap.add(JSValuePtr::encode(v), m_nextConstantIndex);
    if (result.second) {
        RegisterID& constant = m_calleeRegisters[m_nextConstantIndex];
        
        ++m_nextConstantIndex;

        m_codeBlock->addConstantRegister(JSValuePtr(v));
        return &constant;
    }

    return &registerFor(result.first->second);
}

unsigned BytecodeGenerator::addUnexpectedConstant(JSValuePtr v)
{
    return m_codeBlock->addUnexpectedConstant(v);
}

unsigned BytecodeGenerator::addRegExp(RegExp* r)
{
    return m_codeBlock->addRegExp(r);
}

RegisterID* BytecodeGenerator::emitMove(RegisterID* dst, RegisterID* src)
{
    emitOpcode(op_mov);
    instructions().append(dst->index());
    instructions().append(src->index());
    return dst;
}

RegisterID* BytecodeGenerator::emitUnaryOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src)
{
    emitOpcode(opcodeID);
    instructions().append(dst->index());
    instructions().append(src->index());
    return dst;
}

RegisterID* BytecodeGenerator::emitPreInc(RegisterID* srcDst)
{
    emitOpcode(op_pre_inc);
    instructions().append(srcDst->index());
    return srcDst;
}

RegisterID* BytecodeGenerator::emitPreDec(RegisterID* srcDst)
{
    emitOpcode(op_pre_dec);
    instructions().append(srcDst->index());
    return srcDst;
}

RegisterID* BytecodeGenerator::emitPostInc(RegisterID* dst, RegisterID* srcDst)
{
    emitOpcode(op_post_inc);
    instructions().append(dst->index());
    instructions().append(srcDst->index());
    return dst;
}

RegisterID* BytecodeGenerator::emitPostDec(RegisterID* dst, RegisterID* srcDst)
{
    emitOpcode(op_post_dec);
    instructions().append(dst->index());
    instructions().append(srcDst->index());
    return dst;
}

RegisterID* BytecodeGenerator::emitBinaryOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2, OperandTypes types)
{
    emitOpcode(opcodeID);
    instructions().append(dst->index());
    instructions().append(src1->index());
    instructions().append(src2->index());

    if (opcodeID == op_bitor || opcodeID == op_bitand || opcodeID == op_bitxor ||
        opcodeID == op_add || opcodeID == op_mul || opcodeID == op_sub) {
        instructions().append(types.toInt());
    }

    return dst;
}

RegisterID* BytecodeGenerator::emitEqualityOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2)
{
    if (m_lastOpcodeID == op_typeof) {
        int dstIndex;
        int srcIndex;

        retrieveLastUnaryOp(dstIndex, srcIndex);

        if (src1->index() == dstIndex
            && src1->isTemporary()
            && m_codeBlock->isConstantRegisterIndex(src2->index())
            && m_codeBlock->constantRegister(src2->index() - m_codeBlock->m_numVars).jsValue(m_scopeChain->globalObject()->globalExec()).isString()) {
            const UString& value = asString(m_codeBlock->constantRegister(src2->index() - m_codeBlock->m_numVars).jsValue(m_scopeChain->globalObject()->globalExec()))->value();
            if (value == "undefined") {
                rewindUnaryOp();
                emitOpcode(op_is_undefined);
                instructions().append(dst->index());
                instructions().append(srcIndex);
                return dst;
            }
            if (value == "boolean") {
                rewindUnaryOp();
                emitOpcode(op_is_boolean);
                instructions().append(dst->index());
                instructions().append(srcIndex);
                return dst;
            }
            if (value == "number") {
                rewindUnaryOp();
                emitOpcode(op_is_number);
                instructions().append(dst->index());
                instructions().append(srcIndex);
                return dst;
            }
            if (value == "string") {
                rewindUnaryOp();
                emitOpcode(op_is_string);
                instructions().append(dst->index());
                instructions().append(srcIndex);
                return dst;
            }
            if (value == "object") {
                rewindUnaryOp();
                emitOpcode(op_is_object);
                instructions().append(dst->index());
                instructions().append(srcIndex);
                return dst;
            }
            if (value == "function") {
                rewindUnaryOp();
                emitOpcode(op_is_function);
                instructions().append(dst->index());
                instructions().append(srcIndex);
                return dst;
            }
        }
    }

    emitOpcode(opcodeID);
    instructions().append(dst->index());
    instructions().append(src1->index());
    instructions().append(src2->index());
    return dst;
}

RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, bool b)
{
    return emitLoad(dst, jsBoolean(b));
}

RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, double number)
{
    // FIXME: Our hash tables won't hold infinity, so we make a new JSNumberCell each time.
    // Later we can do the extra work to handle that like the other cases.
    if (number == HashTraits<double>::emptyValue() || HashTraits<double>::isDeletedValue(number))
        return emitLoad(dst, jsNumber(globalData(), number));
    JSValuePtr& valueInMap = m_numberMap.add(number, noValue()).first->second;
    if (!valueInMap)
        valueInMap = jsNumber(globalData(), number);
    return emitLoad(dst, valueInMap);
}

RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, const Identifier& identifier)
{
    JSString*& stringInMap = m_stringMap.add(identifier.ustring().rep(), 0).first->second;
    if (!stringInMap)
        stringInMap = jsOwnedString(globalData(), identifier.ustring());
    return emitLoad(dst, JSValuePtr(stringInMap));
}

RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, JSValuePtr v)
{
    RegisterID* constantID = addConstant(v);
    if (dst)
        return emitMove(dst, constantID);
    return constantID;
}

RegisterID* BytecodeGenerator::emitUnexpectedLoad(RegisterID* dst, bool b)
{
    emitOpcode(op_unexpected_load);
    instructions().append(dst->index());
    instructions().append(addUnexpectedConstant(jsBoolean(b)));
    return dst;
}

RegisterID* BytecodeGenerator::emitUnexpectedLoad(RegisterID* dst, double d)
{
    emitOpcode(op_unexpected_load);
    instructions().append(dst->index());
    instructions().append(addUnexpectedConstant(jsNumber(globalData(), d)));
    return dst;
}

bool BytecodeGenerator::findScopedProperty(const Identifier& property, int& index, size_t& stackDepth, bool forWriting, JSObject*& globalObject)
{
    // Cases where we cannot statically optimize the lookup.
    if (property == propertyNames().arguments || !canOptimizeNonLocals()) {
        stackDepth = 0;
        index = missingSymbolMarker();

        if (shouldOptimizeLocals() && m_codeType == GlobalCode) {
            ScopeChainIterator iter = m_scopeChain->begin();
            globalObject = *iter;
            ASSERT((++iter) == m_scopeChain->end());
        }
        return false;
    }

    size_t depth = 0;
    
    ScopeChainIterator iter = m_scopeChain->begin();
    ScopeChainIterator end = m_scopeChain->end();
    for (; iter != end; ++iter, ++depth) {
        JSObject* currentScope = *iter;
        if (!currentScope->isVariableObject())
            break;
        JSVariableObject* currentVariableObject = static_cast<JSVariableObject*>(currentScope);
        SymbolTableEntry entry = currentVariableObject->symbolTable().get(property.ustring().rep());

        // Found the property
        if (!entry.isNull()) {
            if (entry.isReadOnly() && forWriting) {
                stackDepth = 0;
                index = missingSymbolMarker();
                if (++iter == end)
                    globalObject = currentVariableObject;
                return false;
            }
            stackDepth = depth;
            index = entry.getIndex();
            if (++iter == end)
                globalObject = currentVariableObject;
            return true;
        }
        if (currentVariableObject->isDynamicScope())
            break;
    }

    // Can't locate the property but we're able to avoid a few lookups.
    stackDepth = depth;
    index = missingSymbolMarker();
    JSObject* scope = *iter;
    if (++iter == end)
        globalObject = scope;
    return true;
}

RegisterID* BytecodeGenerator::emitInstanceOf(RegisterID* dst, RegisterID* value, RegisterID* base, RegisterID* basePrototype)
{ 
    emitOpcode(op_instanceof);
    instructions().append(dst->index());
    instructions().append(value->index());
    instructions().append(base->index());
    instructions().append(basePrototype->index());
    return dst;
}

RegisterID* BytecodeGenerator::emitResolve(RegisterID* dst, const Identifier& property)
{
    size_t depth = 0;
    int index = 0;
    JSObject* globalObject = 0;
    if (!findScopedProperty(property, index, depth, false, globalObject) && !globalObject) {
        // We can't optimise at all :-(
        emitOpcode(op_resolve);
        instructions().append(dst->index());
        instructions().append(addConstant(property));
        return dst;
    }

    if (globalObject) {
        bool forceGlobalResolve = false;
        if (m_regeneratingForExceptionInfo) {
#if ENABLE(JIT)
            forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInfoAtBytecodeOffset(instructions().size());
#else
            forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInstructionAtBytecodeOffset(instructions().size());
#endif
        }

        if (index != missingSymbolMarker() && !forceGlobalResolve) {
            // Directly index the property lookup across multiple scopes.
            return emitGetScopedVar(dst, depth, index, globalObject);
        }

#if ENABLE(JIT)
        m_codeBlock->addGlobalResolveInfo(instructions().size());
#else
        m_codeBlock->addGlobalResolveInstruction(instructions().size());
#endif
        emitOpcode(op_resolve_global);
        instructions().append(dst->index());
        instructions().append(globalObject);
        instructions().append(addConstant(property));
        instructions().append(0);
        instructions().append(0);
        return dst;
    }

    if (index != missingSymbolMarker()) {
        // Directly index the property lookup across multiple scopes.
        return emitGetScopedVar(dst, depth, index, globalObject);
    }

    // In this case we are at least able to drop a few scope chains from the
    // lookup chain, although we still need to hash from then on.
    emitOpcode(op_resolve_skip);
    instructions().append(dst->index());
    instructions().append(addConstant(property));
    instructions().append(depth);
    return dst;
}

RegisterID* BytecodeGenerator::emitGetScopedVar(RegisterID* dst, size_t depth, int index, JSValuePtr globalObject)
{
    if (globalObject) {
        emitOpcode(op_get_global_var);
        instructions().append(dst->index());
        instructions().append(asCell(globalObject));
        instructions().append(index);
        return dst;
    }

    emitOpcode(op_get_scoped_var);
    instructions().append(dst->index());
    instructions().append(index);
    instructions().append(depth);
    return dst;
}

RegisterID* BytecodeGenerator::emitPutScopedVar(size_t depth, int index, RegisterID* value, JSValuePtr globalObject)
{
    if (globalObject) {
        emitOpcode(op_put_global_var);
        instructions().append(asCell(globalObject));
        instructions().append(index);
        instructions().append(value->index());
        return value;
    }
    emitOpcode(op_put_scoped_var);
    instructions().append(index);
    instructions().append(depth);
    instructions().append(value->index());
    return value;
}

RegisterID* BytecodeGenerator::emitResolveBase(RegisterID* dst, const Identifier& property)
{