[Code generation] added missing file

include/codegen.h

@@ -0,0 +1,29 @@
+#include "ast.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/IRBuilder.h"
+
+namespace tdl
+{
+
+class context {
+public:
+  context();
+  llvm::LLVMContext* handle();
+
+private:
+  llvm::LLVMContext handle_;
+};
+
+class module {
+public:
+  module(const std::string &name, context *ctx);
+  llvm::Module* handle();
+  llvm::IRBuilder<>& builder();
+
+private:
+  llvm::Module handle_;
+  llvm::IRBuilder<> builder_;
+};
+
+
+}