From af85bb4b1578069d41385f1397fd593d1242230d Mon Sep 17 00:00:00 2001
From: Jared Roesch <roeschinc@gmail.com>
Date: Wed, 4 Apr 2018 23:11:29 -0700
Subject: [PATCH] Add type checker skeleton from sslyu (#7)

Add type checker skeleton
---
 relay/include/relay/typechecker.h | 43 ++++++++++++++
 relay/python/relay/tyck.py        |  5 ++
 relay/src/relay/typechecker.cc    | 97 +++++++++++++++++++++++++++++++
 3 files changed, 145 insertions(+)
 create mode 100644 relay/include/relay/typechecker.h
 create mode 100644 relay/python/relay/tyck.py
 create mode 100644 relay/src/relay/typechecker.cc

diff --git a/relay/include/relay/typechecker.h b/relay/include/relay/typechecker.h
new file mode 100644
index 0000000000000..e422e40b4d1eb
--- /dev/null
+++ b/relay/include/relay/typechecker.h
@@ -0,0 +1,43 @@
+/*!
+ *  Copyright (c) 2017 by Contributors
+ * \file environment.h
+ * \brief Relay typechecker
+ */
+#ifndef NNVM_RELAY_TYPECHECKER_H_
+#define NNVM_RELAY_TYPECHECKER_H_
+
+#include <unordered_map>
+#include "node.h"
+#include "expr_functor.h"
+#include "environment.h"
+
+namespace nnvm {
+namespace relay {
+
+class Typechecker : public ExprFunctor<Type(const Expr & n)>  {
+public:
+  Environment env;
+  Typechecker();
+  Typechecker(Environment env) : env(env) {}
+  Type Check(const Expr & expr);
+  Type VisitExpr_(const LocalIdNode* op);
+  Type VisitExpr_(const GlobalIdNode* op);
+  Type VisitExpr_(const IntrinsicIdNode* op);
+  Type VisitExpr_(const FloatLitNode* op);
+  Type VisitExpr_(const BoolLitNode* op);
+  Type VisitExpr_(const IntLitNode* op);
+  Type VisitExpr_(const TensorLitNode* op);
+  Type VisitExpr_(const ProductLitNode* op);
+  Type VisitExpr_(const CastNode* op);
+  Type VisitExpr_(const ParamNode* op);
+  Type VisitExpr_(const FunctionNode* op);
+  Type VisitExpr_(const CallNode* op);
+  Type VisitExpr_(const DebugNode* op);
+  Type VisitExpr_(const UnaryOpNode* op);
+  Type VisitExpr_(const BinaryOpNode* op);
+  Type VisitExpr_(const AssignmentNode* op);
+};
+
+}  // namespace relay
+}  // namespace nnvm
+#endif  // NNVM_RELAY_TYPECHECKER_H_
diff --git a/relay/python/relay/tyck.py b/relay/python/relay/tyck.py
new file mode 100644
index 0000000000000..cec2d8aa7802f
--- /dev/null
+++ b/relay/python/relay/tyck.py
@@ -0,0 +1,5 @@
+"""FFI constructors of all relay AST nodes."""
+
+from tvm._ffi.function import _init_api
+
+_init_api("nnvm.tyck", __name__)
diff --git a/relay/src/relay/typechecker.cc b/relay/src/relay/typechecker.cc
new file mode 100644
index 0000000000000..00833b4273b1e
--- /dev/null
+++ b/relay/src/relay/typechecker.cc
@@ -0,0 +1,97 @@
+/*!
+ *  Copyright (c) 2018 by Contributors
+ * \file typechecker.cc
+ * \brief Relay typechecker
+ */
+
+#include <nnvm/relay/typechecker.h>
+#include <vector>
+
+namespace nnvm {
+namespace relay {
+
+using namespace tvm::runtime;
+
+class TypecheckerError : public std::exception {
+ public:
+  std::string message;
+  explicit TypecheckerError(std::string message) : message(message) {}
+
+  const char *what() const noexcept { return this->message.c_str(); }
+};
+
+Typechecker::Typechecker() : env() {}
+
+Type Typechecker::Check(const Expr &expr) { return this->VisitExpr(expr); }
+
+Type Typechecker::VisitExpr_(const LocalIdNode *op) {
+  throw TypecheckerError("LocalIdNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const GlobalIdNode *op) {
+  throw TypecheckerError("GlobalIdNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const IntrinsicIdNode *op) {
+  throw TypecheckerError("IntrinsicIdNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const FloatLitNode *op) {
+  throw TypecheckerError("FloatLitNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const BoolLitNode *op) {
+  throw TypecheckerError("BoolLitNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const IntLitNode *op) {
+  throw TypecheckerError("IntLitNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const TensorLitNode *op) {
+  throw TypecheckerError("TensorLitNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const ProductLitNode *op) {
+  throw TypecheckerError("ProductLitNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const CastNode *op) {
+  throw TypecheckerError("CastNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const ParamNode *op) {
+  throw TypecheckerError("ParamNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const FunctionNode *op) {
+  throw TypecheckerError("FunctionNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const CallNode *op) {
+  throw TypecheckerError("CallNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const DebugNode *op) {
+  throw TypecheckerError("DebugNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const UnaryOpNode *op) {
+  throw TypecheckerError("UnaryOpNode not implemented");
+}
+
+Type Typechecker::VisitExpr_(const BinaryOpNode *op) {
+  throw TypecheckerError("BinaryOpNode not implmented");
+}
+
+Type Typechecker::VisitExpr_(const AssignmentNode *op) {
+  throw TypecheckerError("AssignmentNode not implemented");
+}
+
+TVM_REGISTER_API("nnvm.tyck.check")
+    .set_body([](TVMArgs args, TVMRetValue *ret) {
+      *ret = IntTypeNode::make(10);
+    });
+
+}  // namespace relay
+}  // namespace nnvm