manupa-arm commented on a change in pull request #7398: URL: https://github.com/apache/tvm/pull/7398#discussion_r576082419
########## File path: src/target/metadata_module.cc ########## @@ -0,0 +1,108 @@ +/* + * 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. + */ + +/*! + * \file metadata_module.cc + * \brief Defines functions that build MetadataModules for C++ and C runtimes. + */ + +#include "metadata_module.h" + +#include "../runtime/meta_data.h" +#include "llvm/llvm_module.h" +#include "source/source_module.h" + +namespace tvm { +namespace codegen { + +/*! + * \brief Create a metadata module wrapper. The helper is used by different + * codegens, such as graph runtime codegen and the vm compiler. + * + * \param params The metadata for initialization of all modules. + * \param target_module the internal module that is compiled by tvm. + * \param ext_modules The external modules that needs to be imported inside the metadata + * module(s). + * \param target The target that all the modules are compiled for + * \return The created metadata module that manages initialization of metadata. + */ +runtime::Module CreateMetadataModule( + const std::unordered_map<std::string, runtime::NDArray>& params, + tvm::runtime::Module target_module, const Array<runtime::Module>& ext_modules, Target target) { + Array<tvm::runtime::Module> csource_modules; + Array<tvm::runtime::Module> binary_modules; + + auto DSOExportable = [](tvm::runtime::Module& mod) { + return !std::strcmp(mod->type_key(), "llvm") || !std::strcmp(mod->type_key(), "c"); + }; + + // Wrap all submodules in the initialization wrapper. + std::unordered_map<std::string, std::vector<std::string>> sym_metadata; + for (tvm::runtime::Module mod : ext_modules) { + auto pf_sym = mod.GetFunction("get_symbol"); + auto pf_var = mod.GetFunction("get_const_vars"); + std::vector<std::string> arrays; + if (pf_sym != nullptr && pf_var != nullptr) { + String symbol = pf_sym(); + Array<String> variables = pf_var(); + for (size_t i = 0; i < variables.size(); i++) { + arrays.push_back(variables[i].operator std::string()); + } + ICHECK_EQ(sym_metadata.count(symbol), 0U) << "Found duplicated symbol: " << symbol; + sym_metadata[symbol] = arrays; + } + // We only need loading of serialized constant data + // if there are constants present and required by the + // runtime module to be initialized by the binary + // metadata module. If not rest of the modules are + // wrapped in c-source metadata module. + + // TODO(@manupa-arm) : we should be able to use csource_metadata + // if the variables are empty when all the runtime modules implement get_func_names + if (arrays.empty() && DSOExportable(mod) && target->kind->name == "c") { + csource_modules.push_back(mod); + } else { + binary_modules.push_back(mod); + } + } + + if (target.defined() && + target->GetAttr<String>("runtime").value_or(String("")) == kTvmRuntimeCrt) { + if (target->kind->name == "c") { + csource_modules.push_back(target_module); + target_module = CreateCSourceCrtMetadataModule(csource_modules, target); + } else if (target->kind->name == "llvm") { + binary_modules.push_back(target_module); Review comment: @areusch , few clarfications : 1. The MetadataModule of type "metadata" is a another module that get loaded using ProcessModuleBlob in c++ runtime. Therefore, I would not agree to "MetadataModule is needed to export Modules ". For e.g., currently ARM Ethos-N that uses ProcessModuleBlob does not require MetadataModule of type "metadata" as it does not need any constants to be loaded into it in the init process. Having said that, what I agree with you is that ProcessModuleBlob should not be the way to do things in C runtime -- more specifically in uTVM environments. So you can think of MetadataModule of type "metadata" as a peer to all runtime modules that gets "packed" to use ProcessModuleBlob in the runtime. 2. Similarly, I would not agree "target_host parses binary configuration data in MetadataModule and then configures any runtime libraries or accelerators", because MetadataModule of type "metadata" only have the constants and other binaries go inside devc.c/o independently of MetadataModule of type "metadata". I agree that " C runtime does not want to require any startup procedure that involves parsing binary blobs using RAM--instead, this must happen at code-generation time.". "This means that we need to do a better job here of organizing Module according to the DLContext which will be executing those modules." -- This I agree. First thing is we need to move away from the assumption that BYOC flows always generate non-DSO-exportable runtime.Modules that is not currently true for our ongoing ARM Ethos-U work. We will be producing a DSOExportable runtime.Module. One side note to this, we might want to integrate the BYOC (possiblly not call it BYOC :) ) in the compilation pathway as it offers IRModule --> runtime.Module conversion generally and TVM's internal module compilation is "a" way of producing it. I have made a similiar comment here : https://github.com/apache/tvm/pull/7428 So towards that goal, I think we need a mechanism to identify the DLContext without relying on their type being "c" or "llvm" as they could possiblly be coming from a BYOC flow. There should be a primary key in the runtime.Module to say its DLContext, IMHO. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
