可以处理生成加法的IR

src/ir/IRPrinter.cpp

@@ -1,4 +1,55 @@
-// IR 文本输出：
-// - 将 IR 打印为 .ll 风格的文本
-// - 支撑调试与测试对比（diff）
+#include "ir/IR.h"
 
+#include <iostream>
+
+namespace ir {
+
+static const char* OpcodeToString(Opcode op) {
+  switch (op) {
+    case Opcode::Add:
+      return "add";
+    case Opcode::Sub:
+      return "sub";
+    case Opcode::Mul:
+      return "mul";
+    case Opcode::Div:
+      return "div";
+    case Opcode::Ret:
+      return "ret";
+  }
+  return "?";
+}
+
+void IRPrinter::Print(const Module& module) {
+  for (const auto& func : module.functions()) {
+    std::cout << "define i32 @" << func->name() << "() {\n";
+    const auto* bb = func->entry();
+    if (!bb) {
+      std::cout << "}\n";
+      continue;
+    }
+    for (const auto& instPtr : bb->instructions()) {
+      const auto* inst = instPtr.get();
+      switch (inst->opcode()) {
+        case Opcode::Add:
+        case Opcode::Sub:
+        case Opcode::Mul:
+        case Opcode::Div: {
+          auto* bin = static_cast<const BinaryInst*>(inst);
+          std::cout << "  " << bin->name() << " = " << OpcodeToString(bin->opcode())
+                    << " " << bin->lhs()->name() << ", " << bin->rhs()->name()
+                    << "\n";
+          break;
+        }
+        case Opcode::Ret: {
+          auto* ret = static_cast<const ReturnInst*>(inst);
+          std::cout << "  ret " << ret->value()->name() << "\n";
+          break;
+        }
+      }
+    }
+    std::cout << "}\n";
+  }
+}
+
+}  // namespace ir