[MLIR] Graph pass to lower ngraph to ngraph dialect (#3835)

*  WIP graph pass to lower ngraph to ngraph dialect

* resolved compiler errors

* - refactor ngraph-dialect to graph pass

* - fix compilation issue
- unit test passes

*  - style fix

* Addressed PR comments

* - move NgDialectConversionPass to anonymous namespace

* - use getModule() to access module inside the graph pass
- address PR comments

*  - fix failing unit test case for negative padding
- make builder as an object isntead of pointer to an object

* Address PR Comments

src/contrib/mlir/CMakeLists.txt

@@ -32,6 +32,8 @@ set(SRC
     core/ngraph_dialect/ops.cpp
     core/pass/mlir_subgraph_extraction.cpp
     core/pass/mlir_subgraph_extraction.hpp
+    core/pass/ng_dialect_builder.cpp
+    core/pass/ng_dialect_builder.hpp
     runtime/cpu/memory_manager.cpp
     runtime/cpu/cpu_runtime.cpp
     utils.cpp

src/contrib/mlir/core/compiler.hpp

@@ -63,9 +63,6 @@ namespace ngraph
                 static void init();
 
             public:
-                using TensorList = std::vector<descriptor::Tensor*>;
-                using TypeList = llvm::SmallVector<mlir::Type, 4>;
-
                 MLIRCompiler(const ngraph::op::CompiledKernel* compiled_kernel,
                              mlir::MLIRContext& context)
                     : m_compiledKernel(compiled_kernel)
@@ -79,52 +76,12 @@ namespace ngraph
                 void compile();
 
                 mlir::OwningModuleRef& get_module() { return m_module; }
-            private:
-                struct TensorInfo
-                {
-                    // MLIR values this tensor maps to.
-                    mlir::Value* m_value;
-                };
-
             private:
                 // Converts an nGraph sub-graph to MLIR nGraph dialect.
                 void buildNgDialectModule();
-                void buildNgDialect();
                 // Applies any nGraph dialect optimizations
                 void optimizeNgDialect() { /*TODO: Add Core NG dialect optimizations */}
 
-                mlir::Type getMlirType(const descriptor::Tensor* tensor);
-                mlir::Type getMlirType(const element::Type& type);
-                mlir::Type getMlirType(const ngraph::Node* node);
-
-                TensorInfo getTensorValue(descriptor::Tensor* tensor);
-                void updateTensorValue(descriptor::Tensor* tensor, mlir::Value* value);
-
-                template <typename Op>
-                static mlir::Operation* createOp(MLIRCompiler& compiler, const ngraph::Node* ngNode)
-                {
-                    throw std::runtime_error("Unimplemented op '" + ngNode->description() +
-                                             "' in MLIR Compiler");
-                }
-
-                // Generic op lowerer to ng dialect.
-                // Simply maps ngraph tensors to values and generate an OP. No op-specific logic.
-                template <typename Op>
-                mlir::Operation* createGenericOp(const ngraph::Node* ngNode);
-
-                template <typename RedOp>
-                mlir::Operation* createIndexReduction(const ngraph::Node* ngNode);
-
-                void createReturn();
-
-                /// Converts nGraph shape-like types \p ng_shape to MLIR shape \p mlir_shape.
-                template <typename T>
-                void getMlirShape(T ngShape, llvm::SmallVectorImpl<int64_t>& mlirShape);
-
-                /// Converts an ngraph shape to an I64 array attribute
-                template <typename T>
-                mlir::ArrayAttr getShapeAsAttr(T ngShape);
-
             private:
                 // Sub-graph to be compiled and executed with MLIR.
                 const ngraph::op::CompiledKernel* m_compiledKernel;
@@ -132,20 +89,8 @@ namespace ngraph
                 // MLIR context that holds all the MLIR information related to the sub-graph
                 // compilation.
                 mlir::MLIRContext& m_context;
-
                 mlir::OwningModuleRef m_module;
-                std::unique_ptr<mlir::OpBuilder> m_builder;
-
-                using TensorToInfo = std::pair<descriptor::Tensor*, TensorInfo>;
-                using TensorToInfoMap = std::unordered_map<descriptor::Tensor*, TensorInfo>;
-                using MLIRCompOpFunction =
-                    std::function<mlir::Operation*(MLIRCompiler& compiler, const ngraph::Node*)>;
-                using MLIRCompOpMap = std::unordered_map<std::type_index, MLIRCompOpFunction>;
 
-                // Maps tensor to the value it represents in the IR
-                // use for MLIR dialect gen
-                TensorToInfoMap m_tensorToValueMap;
-                static const MLIRCompOpMap opDispatcher;
                 // Global initialization for MLIR compiler
                 static bool initialized;
             };

src/contrib/mlir/core/ngraph_dialect/ops.cpp

@@ -277,14 +277,11 @@ mlir::LogicalResult verifyOp(NGConvolutionOp* op)
         auto s = std::get<0>(attrs).cast<IntegerAttr>().getInt();
         auto pb = std::get<1>(attrs).cast<IntegerAttr>().getInt();
         auto pa = std::get<2>(attrs).cast<IntegerAttr>().getInt();
+
         if (s <= 0)
         {
             return op->emitOpError("Window stride must be non-negative");
         }
-        if (pb < 0 || pa < 0)
-        {
-            return op->emitOpError("Paddings must be positive");
-        }
         stridesVal.push_back(s);
         padBelowVal.push_back(pb);
         padAboveVal.push_back(pa);

src/contrib/mlir/core/pass/ng_dialect_builder.hpp

+//*****************************************************************************
+// Copyright 2017-2019 Intel Corporation
+//
+// Licensed 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.
+//*****************************************************************************
+
+// NOTE: This file follows nGraph format style.
+// Follows nGraph naming convention for public APIs only, else MLIR naming convention.
+
+#pragma once
+
+#include "contrib/mlir/core/compiler.hpp"
+#include "contrib/mlir/runtime/cpu/memory_manager.hpp"
+#include "ngraph/check.hpp"
+#include "ngraph/descriptor/tensor.hpp"
+#include "ngraph/node.hpp"
+
+#include <mlir/ExecutionEngine/MemRefUtils.h>
+#include <mlir/IR/Builders.h>
+#include <mlir/IR/Module.h>
+#include <mlir/IR/Types.h>
+#include <mlir/Pass/Pass.h>
+
+#include <typeindex>
+#include <unordered_map>
+#include <vector>
+
+using namespace ngraph::runtime::ngmlir;
+
+namespace ngraph
+{
+    namespace pass
+    {
+        std::unique_ptr<mlir::Pass>
+            createNgDialectConversionPass(const ngraph::op::CompiledKernel* compiledKernel,
+                                          mlir::MLIRContext* context);
+    }
+}