unfinishe

docs/dev/relay_bring_your_own_codegen.rst

@@ -520,10 +520,26 @@ So that users can configure whether to include your compiler when configuring TV
 Implement a Codegen for Your Representation
 *******************************************
 
-Although we have demonstrated how to implement a C codegen, your hardware may require other forms of graph representation, such as JSON. In this case, you can slightly modify ``CodegenC`` class we have implemented to generate your own graph representation, and implement a customized runtime module to let TVM runtime know how this graph representation should be executed. **(TBA)**
+Although we have demonstrated how to implement a C codegen, your hardware may require other forms of graph representation, such as JSON. In this case, you can slightly modify ``CodegenC`` class we have implemented to generate your own graph representation, and implement a customized runtime module to let TVM runtime know how this graph representation should be executed.
+
+Speifically, our goal is to implement the following customized TVM runtime module:
+
+.. code-block:: c++
+
+  runtime::Module MyIRCompiler(const NodeRef& ref) {
+    graph_ir = MyCodeGen(ref); // Note 1
+    return CreateMyModule(graph_ir); // Note 2
+  }
+
+**Note 1**: ``MyCodeGen`` can be fully-customized as long as it takes a subgraph (``NodeRef``) and outputs a representation you prefer. You don't have to register ``MyCodeGen`` to TVM because this is the only place it will be used.
+
+**Note 2**: ``CreateMyModule`` instantiates a customized TVM module with the subgraph in your representation. It means this module is able to execute the subgraph when TVM invokes its subgraph ID on the fly.
+
+In the following sections, we are going to introduce how to implement ``MyCodeGen`` and ``CreateMyModule``.
+
+Implement MyCodeGen
+===================
 
-Implement CodegenJSON
-=====================
 
 Implement Customized Runtime
 ============================