[TVMScript] New Parser: Part B (#217)

This PR is organized as follows:

- The basic infrastructure: `tvm/script/ir_builder/base.{py/h/cc} `
- IRBuilder for package `tvm.ir`: `tvm/script/ir_builder/ir/*.{py/h/cc}`
- IRBuilder for package `tvm.tir`: `tvm/script/ir_builder/tir/*.{py/h/cc}`

include/tvm/script/ir_builder/base.h

@@ -0,0 +1,166 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+#ifndef TVM_SCRIPT_IR_BUILDER_BASE_H_
+#define TVM_SCRIPT_IR_BUILDER_BASE_H_
+
+#include <tvm/ir/expr.h>
+#include <tvm/ir/function.h>
+#include <tvm/node/node.h>
+
+#include <vector>
+
+namespace tvm {
+namespace script {
+namespace ir_builder {
+
+////////////////////////////// Core Infra: Frame //////////////////////////////
+
+class IRBuilderFrameNode : public runtime::Object {
+ public:
+  std::vector<runtime::TypedPackedFunc<void()>> callbacks;
+
+  void VisitAttrs(tvm::AttrVisitor* v) {
+    // `callbacks` is not visited.
+  }
+
+  static constexpr const char* _type_key = "script.ir_builder.IRBuilderFrame";
+  TVM_DECLARE_BASE_OBJECT_INFO(IRBuilderFrameNode, runtime::Object);
+
+ public:
+  virtual ~IRBuilderFrameNode() = default;
+  virtual void EnterWithScope();
+  virtual void ExitWithScope();
+
+  void AddCallback(runtime::TypedPackedFunc<void()> callback);
+};
+
+class IRBuilderFrame : public runtime::ObjectRef {
+ public:
+  virtual ~IRBuilderFrame() = default;
+  TVM_DEFINE_MUTABLE_NOTNULLABLE_OBJECT_REF_METHODS(IRBuilderFrame, ObjectRef, IRBuilderFrameNode);
+
+ protected:
+  IRBuilderFrame() = default;
+
+ public:
+  inline void EnterWithScope();
+  inline void ExitWithScope();
+};
+
+////////////////////////////// Core Infra: Builder //////////////////////////////
+///
+class IRBuilderNode : public runtime::Object {
+ public:
+  runtime::Array<IRBuilderFrame> frames;
+  Optional<ObjectRef> result;
+
+  void VisitAttrs(tvm::AttrVisitor* v) {
+    v->Visit("frames", &frames);
+    v->Visit("result", &result);
+  }
+
+  static constexpr const char* _type_key = "script.ir_builder.IRBuilder";
+  TVM_DECLARE_FINAL_OBJECT_INFO(IRBuilderNode, runtime::Object);
+
+ public:
+  template <typename TFrame>
+  inline Optional<TFrame> FindFrame() const;
+  template <typename TFrame>
+  inline Optional<TFrame> GetLastFrame() const;
+  template <typename TObjectRef>
+  inline TObjectRef Get() const;
+};
+
+class IRBuilder : public runtime::ObjectRef {
+ public:
+  IRBuilder();
+  TVM_DEFINE_MUTABLE_NOTNULLABLE_OBJECT_REF_METHODS(IRBuilder, ObjectRef, IRBuilderNode);
+
+ public:
+  void EnterWithScope();
+  void ExitWithScope();
+  static IRBuilder Current();
+  template <class TObjectRef>
+  inline static TObjectRef Name(String name, TObjectRef obj);
+};
+
+////////////////////////////// Details //////////////////////////////
+
+namespace details {
+
+class Namer {
+ public:
+  using FType = NodeFunctor<void(const ObjectRef&, String)>;
+  static FType& vtable();
+  static void Name(ObjectRef node, String name);
+};
+
+}  // namespace details
+
+template <class TObjectRef>
+inline TObjectRef IRBuilder::Name(String name, TObjectRef obj) {
+  details::Namer::Name(obj, name);
+  return Downcast<TObjectRef>(obj);
+}
+
+inline void IRBuilderFrame::EnterWithScope() {
+  ICHECK(data_ != nullptr);
+  static_cast<IRBuilderFrameNode*>(data_.get())->EnterWithScope();
+}
+
+inline void IRBuilderFrame::ExitWithScope() {
+  ICHECK(data_ != nullptr);
+  static_cast<IRBuilderFrameNode*>(data_.get())->ExitWithScope();
+  data_.reset();
+}
+
+template <typename TFrame>
+inline Optional<TFrame> IRBuilderNode::FindFrame() const {
+  using TFrameNode = typename TFrame::ContainerType;
+  for (auto it = frames.rbegin(); it != frames.rend(); ++it) {
+    if (const TFrameNode* p = (*it).template as<TFrameNode>()) {
+      return GetRef<TFrame>(p);
+    }
+  }
+  return NullOpt;
+}
+
+template <typename TFrame>
+inline Optional<TFrame> IRBuilderNode::GetLastFrame() const {
+  using TFrameNode = typename TFrame::ContainerType;
+  if (!frames.empty() && frames.back()->IsInstance<TFrameNode>()) {
+    return Downcast<TFrame>(frames.back());
+  }
+  return NullOpt;
+}
+
+template <typename TObjectRef>
+inline TObjectRef IRBuilderNode::Get() const {
+  using TObject = typename TObjectRef::ContainerType;
+  CHECK(result.defined()) << "IndexError: No result exists in IRBuilder yet";
+  const auto* n = result.as<TObject>();
+  CHECK(n != nullptr) << "IndexError: IRBuilder result is not of type: " << TObject::_type_key;
+  return GetRef<TObjectRef>(n);
+}
+
+}  // namespace ir_builder
+}  // namespace script
+}  // namespace tvm
+
+#endif  // TVM_SCRIPT_IR_BUILDER_BASE_H_

include/tvm/script/ir_builder/ir/frame.h

@@ -0,0 +1,61 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+#ifndef TVM_SCRIPT_IR_BUILDER_IR_FRAME_H_
+#define TVM_SCRIPT_IR_BUILDER_IR_FRAME_H_
+
+#include <tvm/ir/expr.h>
+#include <tvm/ir/function.h>
+#include <tvm/node/node.h>
+#include <tvm/script/ir_builder/base.h>
+
+#include <vector>
+
+namespace tvm {
+namespace script {
+namespace ir_builder {
+
+class IRModuleFrameNode : public IRBuilderFrameNode {
+ public:
+  Array<GlobalVar> global_vars;
+  Array<BaseFunc> functions;
+
+  void VisitAttrs(tvm::AttrVisitor* v) {
+    IRBuilderFrameNode::VisitAttrs(v);
+    v->Visit("global_vars", &global_vars);
+    v->Visit("functions", &functions);
+  }
+
+  static constexpr const char* _type_key = "script.ir_builder.IRModuleFrame";
+  TVM_DECLARE_FINAL_OBJECT_INFO(IRModuleFrameNode, IRBuilderFrameNode);
+
+ public:
+  void ExitWithScope() final;
+};
+
+class IRModuleFrame : public IRBuilderFrame {
+ public:
+  TVM_DEFINE_MUTABLE_NOTNULLABLE_OBJECT_REF_METHODS(IRModuleFrame, IRBuilderFrame,
+                                                    IRModuleFrameNode);
+};
+
+}  // namespace ir_builder
+}  // namespace script
+}  // namespace tvm
+
+#endif  // TVM_SCRIPT_IR_BUILDER_IR_FRAME_H_

include/tvm/script/ir_builder/ir/ir.h

@@ -0,0 +1,39 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+#ifndef TVM_SCRIPT_IR_BUILDER_IR_IR_H_
+#define TVM_SCRIPT_IR_BUILDER_IR_IR_H_
+
+#include <tvm/ir/expr.h>
+#include <tvm/ir/function.h>
+#include <tvm/node/node.h>
+#include <tvm/script/ir_builder/ir/frame.h>
+
+#include <vector>
+
+namespace tvm {
+namespace script {
+namespace ir_builder {
+
+TVM_DLL IRModuleFrame IRModule();
+
+}
+}  // namespace script
+}  // namespace tvm
+
+#endif  // TVM_IR_IR_BUILDER_IR_IR_H_