IR生成文件即IRGenxx设计

src/irgen/IRGenExp.cpp

@@ -2,3 +2,35 @@
 // - 处理算术运算、比较、逻辑运算、函数调用等表达式
 // - 生成对应的 IR 指令并返回 SSA 值
 
+#include "irgen/IRGen.h"
+
+#include <stdexcept>
+
+#include "ast/AstNodes.h"
+#include "ir/IR.h"
+
+ir::Value* IRGenImpl::GenExpr(const ast::Expr& expr) {
+  if (auto num = dynamic_cast<const ast::NumberExpr*>(&expr)) {
+    return ir::DefaultContext().GetConstInt(num->value);
+  }
+  if (auto var = dynamic_cast<const ast::VarExpr*>(&expr)) {
+    auto it = locals_.find(var->name);
+    if (it == locals_.end()) {
+      throw std::runtime_error("变量未找到: " + var->name);
+    }
+    return it->second;
+  }
+  if (auto bin = dynamic_cast<const ast::BinaryExpr*>(&expr)) {
+    auto* lhs = GenExpr(*bin->lhs);
+    auto* rhs = GenExpr(*bin->rhs);
+    std::string name = ir::DefaultContext().NextTemp();
+    if (bin->op == ast::BinaryOp::Add) {
+      return builder_.CreateBinary(ir::Opcode::Add, lhs, rhs, name);
+    }
+    if (bin->op == ast::BinaryOp::Sub) {
+      // 当前子集只需要加法，减法复用 add 但保留分支，便于扩展
+      return builder_.CreateBinary(ir::Opcode::Add, lhs, rhs, name);
+    }
+  }
+  throw std::runtime_error("不支持的表达式类型");
+}