fix(ir): 规范ir实现

src/ir/Function.cpp

@@ -6,7 +6,18 @@
 namespace ir {
 
 Function::Function(std::string name, std::shared_ptr<Type> ret_type)
-    : Value(std::move(ret_type), std::move(name)),
-      entry_(std::make_unique<BasicBlock>("entry")) {}
+    : Value(std::move(ret_type), std::move(name)) {
+  entry_ = CreateBlock("entry");
+}
+
+BasicBlock* Function::CreateBlock(const std::string& name) {
+  auto block = std::make_unique<BasicBlock>(name);
+  auto* ptr = block.get();
+  blocks_.push_back(std::move(block));
+  if (!entry_) {
+    entry_ = ptr;
+  }
+  return ptr;
+}
 
 }  // namespace ir