refactor(irgen): IR改成alloca和store形式

src/ir/IR.h

@@ -19,6 +19,7 @@ class Context {
   ~Context();
   const std::shared_ptr<Type>& Void();
   const std::shared_ptr<Type>& Int32();
+  const std::shared_ptr<Type>& PtrInt32();
   // 去重创建 i32 常量。
   ConstantInt* GetConstInt(int v);
   // 生成临时名称，如 %t0、%t1 ...
@@ -27,6 +28,7 @@ class Context {
  private:
   std::shared_ptr<Type> void_;
   std::shared_ptr<Type> int32_;
+  std::shared_ptr<Type> ptr_i32_;
   std::unordered_map<int, std::unique_ptr<ConstantInt>> const_ints_;
   int temp_index_ = 0;
 };
@@ -35,11 +37,12 @@ Context& DefaultContext();
 
 class Type {
  public:
-  enum class Kind { Void, Int32 };
+  enum class Kind { Void, Int32, PtrInt32 };
   explicit Type(Kind k) : kind_(k) {}
   Kind kind() const { return kind_; }
   static std::shared_ptr<Type> Void();
   static std::shared_ptr<Type> Int32();
+  static std::shared_ptr<Type> PtrInt32();
 
  private:
   Kind kind_;
@@ -68,7 +71,7 @@ class ConstantInt : public Value {
   int value_{};
 };
 
-enum class Opcode { Add, Sub, Mul, Ret };
+enum class Opcode { Add, Sub, Mul, Alloca, Load, Store, Ret };
 
 class Instruction : public Value {
  public:
@@ -101,6 +104,31 @@ class ReturnInst : public Instruction {
   Value* value_;
 };
 
+class AllocaInst : public Instruction {
+ public:
+  explicit AllocaInst(std::string name);
+};
+
+class LoadInst : public Instruction {
+ public:
+  LoadInst(Value* ptr, std::string name);
+  Value* ptr() const { return ptr_; }
+
+ private:
+  Value* ptr_;
+};
+
+class StoreInst : public Instruction {
+ public:
+  StoreInst(Value* val, Value* ptr);
+  Value* value() const { return value_; }
+  Value* ptr() const { return ptr_; }
+
+ private:
+  Value* value_;
+  Value* ptr_;
+};
+
 class BasicBlock {
  public:
   explicit BasicBlock(std::string name) : name_(std::move(name)) {}
@@ -158,6 +186,9 @@ class IRBuilder {
   BinaryInst* CreateAdd(Value* lhs, Value* rhs, const std::string& name) {
     return CreateBinary(Opcode::Add, lhs, rhs, name);
   }
+  AllocaInst* CreateAllocaI32(const std::string& name);
+  LoadInst* CreateLoad(Value* ptr, const std::string& name);
+  StoreInst* CreateStore(Value* val, Value* ptr);
   ReturnInst* CreateRet(Value* v);
 
  private: