背景说明

在编译器中端开发中，需要将 SlowPathLowering 中的字节码 lowering 逻辑迁移到 xxxGraphBuilder。这两者使用不同的 API 和架构：

• SlowPathLowering：基于 Circuit 的门级 IR，使用 GateRef、GateAccessor、CircuitBuilder 等 API
• xxxGraphBuilder：基于图结构的 IR，使用 ValueVertex、ControlVertex、NewVertex 等 API，采用类似 V8 Maglev 的 CFG (控制流图) 结构

迁移难点包括：

1. IR 结构差异：从扁平的 Circuit 迁移到分层结构的 CFG
2. API 映射：GateRef → ValueVertex*，CircuitBuilder → NewVertex<XxxVertex>
3. 参数获取：acc_.GetValueIn() → GetConstDataId()/GetImmediate()/LoadRegister()
4. 条件编译：正确处理 #if ECMASCRIPT_ENABLE_IC 等宏

AI 需要理解两套 API 的对应关系，并正确处理字节码输入格式。

案例：批量生成 LdLexVar & StLexVar CommonStub

提示词

帮我生成一个 CommonStub，并且加上 call_signature，生成在 standalone/arkcompiler/ets_runtime/ecmascript/compiler/common_stubs.cpp，内容使用 void SlowPathLowering::LowerLdLexVar(GateRef gate)，并给 void xxxGraphBuilder::LowerLdLexVar() 使用

同理，StLexVar 也参考 void SlowPathLowering::LowerStLexVar(GateRef gate) 构建 CommonStub，并且 void xxxGraphBuilder::LowerStLexVar() 会调用这个 stub。

AI 生成的代码

1. call_signature.h / common_stub_csigns.h（添加宏定义）

V(LdLexVar)
V(StLexVar)

2. call_signature.cpp（添加签名定义）

DEF_CALL_SIGNATURE(LdLexVar)
{
    CallSignature signature("LdLexVar", 0, 4, ArgumentsOrder::DEFAULT_ORDER, VariableType::JS_ANY());
    *callSign = signature;
    std::array<VariableType, 4> params = {
        VariableType::NATIVE_POINTER(),  // glue
        VariableType::INT32(),           // level
        VariableType::INT32(),           // slot
        VariableType::JS_ANY()           // currentEnv
    };
    callSign->SetParameters(params.data());
    callSign->SetCallConv(CallSignature::CallConv::CCallConv);
}

DEF_CALL_SIGNATURE(StLexVar)
{
    CallSignature signature("StLexVar", 0, 5, ArgumentsOrder::DEFAULT_ORDER, VariableType::JS_ANY());
    *callSign = signature;
    std::array<VariableType, 5> params = {
        VariableType::NATIVE_POINTER(),  // glue
        VariableType::INT32(),           // level
        VariableType::INT32(),           // slot
        VariableType::JS_ANY(),          // currentEnv
        VariableType::JS_ANY()           // value
    };
    callSign->SetParameters(params.data());
    callSign->SetCallConv(CallSignature::CallConv::CCallConv);
}

3. common_stubs.cpp（添加 Stub 实现）

void LdLexVarStubBuilder::GenerateCircuit()
{
    auto env = GetEnvironment();
    GateRef glue = PtrArgument(0);
    GateRef level = Int32Argument(1);
    GateRef slot = Int32Argument(2);
    DEFVARIABLE(currentEnv, VariableType::JS_ANY(), TaggedArgument(3));
    GateRef index = Int32(LexicalEnv::PARENT_ENV_INDEX);
    Label exit(env);
    Label loopHead(env);
    Label loopEnd(env);

    DEFVARIABLE(i, VariableType::INT32(), Int32(0));
    BRANCH(Int32LessThan(*i, level), &loopHead, &exit);
    Bind(&loopHead);
    {
        currentEnv = GetValueFromTaggedArray(glue, *currentEnv, index);
        i = Int32Add(*i, Int32(1));
        BRANCH(Int32LessThan(*i, level), &loopEnd, &exit);
    }
    Bind(&loopEnd);
    {
        LoopEnd(&loopHead);
    }
    Bind(&exit);
    GateRef valueIndex = Int32Add(slot, Int32(LexicalEnv::RESERVED_ENV_LENGTH));
    GateRef result = GetValueFromTaggedArray(glue, *currentEnv, valueIndex);
    Return(result);
}

void StLexVarStubBuilder::GenerateCircuit()
{
    auto env = GetEnvironment();
    GateRef glue = PtrArgument(0);
    GateRef level = Int32Argument(1);
    GateRef slot = Int32Argument(2);
    DEFVARIABLE(currentEnv, VariableType::JS_ANY(), TaggedArgument(3));
    GateRef value = TaggedArgument(4);
    GateRef index = Int32(LexicalEnv::PARENT_ENV_INDEX);
    Label exit(env);
    Label loopHead(env);
    Label loopEnd(env);

    DEFVARIABLE(i, VariableType::INT32(), Int32(0));
    BRANCH(Int32LessThan(*i, level), &loopHead, &exit);
    Bind(&loopHead);
    {
        currentEnv = GetValueFromTaggedArray(glue, *currentEnv, index);
        i = Int32Add(*i, Int32(1));
        BRANCH(Int32LessThan(*i, level), &loopEnd, &exit);
    }
    Bind(&loopEnd);
    {
        LoopEnd(&loopHead);
    }
    Bind(&exit);
    GateRef valueIndex = Int32Add(slot, Int32(LexicalEnv::RESERVED_ENV_LENGTH));
    SetValueToTaggedArray(VariableType::JS_ANY(), glue, *currentEnv, valueIndex, value);
    Return(*currentEnv);
}

4. xxx_graph_builder.cpp（更新调用代码）

void xxxGraphBuilder::LowerLdLexVar()
{
    ValueVertex* level = GetInt32Constant(static_cast<int>(GetImmediate(0)));
    ValueVertex* slot = GetInt32Constant(static_cast<int>(GetImmediate(1)));
    ValueVertex* lexicalEnv = LoadRegister(2);
    ValueVertex* glue = GetGlue();
    SetAcc(NewVertex<CallCommonStubVertex>({glue, level, slot, lexicalEnv}, CommonStubCSigns::LdLexVar));
}

void xxxGraphBuilder::LowerStLexVar()
{
    ValueVertex* level = GetInt32Constant(static_cast<int>(GetImmediate(0)));
    ValueVertex* slot = GetInt32Constant(static_cast<int>(GetImmediate(1)));
    ValueVertex* lexicalEnv = LoadRegister(2);
    ValueVertex* value = GetAcc();
    ValueVertex* glue = GetGlue();
    SetAcc(NewVertex<CallCommonStubVertex>({glue, level, slot, lexicalEnv, value}, CommonStubCSigns::StLexVar));
}

效率对比

代码统计

效率提升