liangfu commented on a change in pull request #4482: [Relay] External codegen URL: https://github.com/apache/incubator-tvm/pull/4482#discussion_r355918787
########## File path: src/relay/backend/contrib/csource/codegen.cc ########## @@ -0,0 +1,229 @@ +/* + * 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. + */ +#include <tvm/relay/expr_functor.h> +#include <tvm/relay/transform.h> +#include <tvm/relay/type.h> +#include <tvm/runtime/module.h> +#include <tvm/runtime/object.h> + +#include <fstream> +#include <sstream> + +#include "../contrib_codegen.h" + +namespace tvm { +namespace relay { +namespace contrib { + +/*! + * \brief An example codegen that is only used for quick prototyping and testing + * purpose. Only several binary options are covered in the CSource builder. Users + * may need to extend them to cover more operators. + */ +class CSourceBuilder : public ExprVisitor, public ExternSourcePrinter { + public: + explicit CSourceBuilder(const std::string& id) { this->subgraph_id_ = id; } + + void VisitExpr_(const VarNode* node) { + subgraph_args_.push_back(node->name_hint()); + out_.clear(); + out_.push_back({node->name_hint(), 0}); + } + + void VisitExpr_(const CallNode* call) final { + std::ostringstream macro_stream; + std::ostringstream decl_stream; + std::ostringstream buf_stream; + + auto op_node = call->op.as<OpNode>(); + std::string func_name = subgraph_id_ + "_" + std::to_string(func_idx++); + + // Make function declaration + macro_stream << "CSOURCE_BINARY_OP_" << call->args.size() << "D(" << func_name << ", "; + + if (GetRef<Op>(op_node) == Op::Get("add")) { + macro_stream << "+"; + } else if (GetRef<Op>(op_node) == Op::Get("subtract")) { + macro_stream << "-"; + } else if (GetRef<Op>(op_node) == Op::Get("multiply")) { + macro_stream << "*"; + } else { + LOG(FATAL) << "Unrecognized op"; + } + + auto in_shape = GetShape(call->args[0]->checked_type()); + for (size_t i = 0; i < in_shape.size(); ++i) { + macro_stream << ", " << in_shape[i]; + } + macro_stream << ");"; + func_decl_.push_back(macro_stream.str()); + + // Make function call when visiting arguments + bool first = true; + decl_stream << func_name << "("; + for (size_t i = 0; i < call->args.size(); ++i) { + VisitExpr(call->args[i]); + for (auto out : out_) { + if (!first) { + decl_stream << ", "; + } + first = false; + decl_stream << out.first; + } + } + + auto type_node = call->checked_type().as<TensorTypeNode>(); + CHECK(type_node != nullptr && runtime::TypeMatch(type_node->dtype, kDLFloat, 32)) + << "Only support single output tensor with float type"; + std::string out = "buf_" + std::to_string(buf_idx_++); + auto out_shape = GetShape(call->checked_type()); + int out_size = 1; + for (size_t i = 0; i < out_shape.size(); ++i) { + out_size *= out_shape[i]; + } + buf_stream << "float* " << out << " = (float*)std::malloc(4 * " << out_size << ");"; + buf_decl_.push_back(buf_stream.str()); + + decl_stream << ", " << out << ");"; + subgraph_body.push_back(decl_stream.str()); + + // Update output buffer + out_.clear(); + out_.push_back({out, out_size}); + } + + /*! + * \brief Emit the source code that invokes C compiler compatible wrappers. + * + * \return The emitted code. + */ + std::string JIT() { + // Write function macros + for (auto decl : func_decl_) { + code_stream_ << decl << "\n"; + } + return JitImpl(subgraph_id_, subgraph_args_, buf_decl_, subgraph_body, out_); + } + + private: + /*! \brief The subgraph id that represents an C source external function. */ + std::string subgraph_id_ = ""; + /*! \brief The index of an external function. */ + int func_idx = 0; + /*! \brief The index of allocated buffers. */ + int buf_idx_ = 0; + /*! \brief The arguments of a C compiler compatible external function. */ + std::vector<std::string> subgraph_args_; + /*! \brief The statements of a C compiler compatible external function. */ + std::vector<std::string> subgraph_body; + /*! \brief The declaration statements of a C compiler compatible external function. */ + std::vector<std::string> func_decl_; + /*! \brief The declaration statements of buffers. */ + std::vector<std::string> buf_decl_; + /*! \brief The name and index pairs for output. */ + std::vector<std::pair<std::string, int>> out_; +}; + +class CSourceCodegen : public ExternCodegenBase { + public: + void CreateExternFunction(const Function& func) { + CHECK(func.defined()) + << "Input error: external codegen expects a Relay function."; + + // Record subgraph ID for runtime invoke. + auto sid = GetSubgraphID(func, "ccompiler"); + + auto builder = CSourceBuilder("ccompiler_" + sid); + builder.VisitExpr(func->body); + code_stream_ << builder.JIT(); + } + + runtime::Module CreateExternModule(const NodeRef& ref) { + // Create headers + code_stream_ << "#include <cstdint>\n"; + code_stream_ << "#include <iostream>\n"; + code_stream_ << "#include <cstdlib>\n"; + code_stream_ << "#include <stdio.h>\n"; + code_stream_ << "#include <cstring>\n"; + code_stream_ << "#include <tvm/runtime/c_runtime_api.h>\n"; + code_stream_ << "#include <dlpack/dlpack.h>\n"; + + // Append some common macro for operator definition. + const char* operator_macro = R"op_marco( + #define CSOURCE_BINARY_OP_1D(p_ID_, p_OP_, p_DIM1_) \ + extern "C" void p_ID_(float* a, float* b, float* out) { \ + for (int64_t i = 0; i < p_DIM1_; ++i) { \ + out[i] = a[i] p_OP_ b[i]; \ + } \ + } + + #define CSOURCE_BINARY_OP_2D(p_ID_, p_OP_, p_DIM1_, p_DIM2_) \ + extern "C" void p_ID_(float* a, float* b, float* out) { \ + for (int64_t i = 0; i < p_DIM1_; ++i) { \ + for (int64_t j = 0; j < p_DIM2_; ++j) { \ + int64_t k = i * p_DIM2_ + j; \ + out[k] = a[k] p_OP_ b[k]; \ + } \ + } \ + } + )op_marco"; Review comment: typo: marco -> macro ? 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