lyb-PW6/Student/task2/cpp/func_gen.cpp

#include "BasicBlock.h"
#include "Constant.h"
#include "Function.h"
#include "IRStmtBuilder.h"
#include "Module.h"
#include "Type.h"

#include <iostream>
#include <memory>

#ifdef DEBUG  // 用于调试信息,大家可以在编译过程中通过" -DDEBUG"来开启这一选项
#define DEBUG_OUTPUT std::cout << __LINE__ << std::endl;  // 输出行号的简单示例
#else
#define DEBUG_OUTPUT
#endif

#define CONST_INT(num) \
    ConstantInt::create(num, module)

#define CONST_FP(num) \
    ConstantFloat::create(num, module) // 得到常数值的表示,方便后面多次用到

using namespace SysYF::IR;

int main() {
    auto module = Module::create("SysYF code");  // module name是什么无关紧要
    auto builder = IRStmtBuilder::create(nullptr, module);
    SysYF::Ptr<Type> Int32Type = Type::get_int32_type(module);

    // add(a, b)
    // 函数参数类型的vector
    std::vector<SysYF::Ptr<Type>> Ints(2, Int32Type);

    //通过返回值类型与参数类型列表得到函数类型
    auto addFunTy = FunctionType::create(Int32Type, Ints);

    // 由函数类型得到函数
    auto addFun = Function::create(addFunTy,
                                    "add", module);

    // BB的名字在生成中无所谓,但是可以方便阅读
    auto bb = BasicBlock::create(module, "entry", addFun);
    
    builder->set_insert_point(bb);                        // 一个BB的开始,将当前插入指令点的位置设在bb
    
    auto retAlloca = builder->create_alloca(Int32Type);   // 在内存中分配返回值的位置
    auto aAlloca = builder->create_alloca(Int32Type);     // 在内存中分配参数a的位置
    auto bAlloca = builder->create_alloca(Int32Type);     // 在内存中分配参数b的位置

    std::vector<SysYF::Ptr<Value>> args;  // 获取add函数的形参,通过Function中的iterator
    for (auto arg = addFun->arg_begin(); arg != addFun->arg_end(); arg++) {
        args.push_back(*arg);   // * 号运算符是从迭代器中取出迭代器当前指向的元素
    }

    builder->create_store(args[0], aAlloca);  // store参数a
    builder->create_store(args[1], bAlloca);  // store参数b

    auto aLoad = builder->create_load(aAlloca);  // load参数a
    auto bLoad = builder->create_load(bAlloca);  // load参数b

    // a+b
    auto add = builder->create_iadd(aLoad, bLoad);
    
    // a+b-1
    auto sub = builder->create_isub(add, CONST_INT(1));

    builder->create_store(sub, retAlloca);
    auto retLoad = builder->create_load(retAlloca);
    builder->create_ret(retLoad);
    builder->create_ret(retLoad);

    // main函数
    auto mainFun = Function::create(FunctionType::create(Int32Type, {}),
                                    "main", module);
    bb = BasicBlock::create(module, "entry", mainFun);
    // BasicBlock的名字在生成中无所谓,但是可以方便阅读
    builder->set_insert_point(bb);

    retAlloca = builder->create_alloca(Int32Type);

    // int a;
    auto a = builder->create_alloca(Int32Type);

    // int b;
    auto b = builder->create_alloca(Int32Type);

    // int c;
    auto c = builder->create_alloca(Int32Type);

    // a = 3;
    builder->create_store(CONST_INT(3), a);
    
    // b = 2;
    builder->create_store(CONST_INT(2), b);
    
    // c = 5;
    builder->create_store(CONST_INT(5), c);
    
    // tmp = add(a, b);
    aLoad = builder->create_load(a);
    bLoad = builder->create_load(b);
    auto tmp = builder->create_call(addFun, {aLoad, bLoad});

    // ret = c + tmp;
    auto cLoad = builder->create_load(c);
    auto ret = builder->create_iadd(cLoad, tmp);
    builder->create_store(ret, retAlloca);
    retLoad = builder->create_load(retAlloca);
    builder->create_ret(retLoad);

    std::cout << module->print();
    return 0;
}