From 39a6e7e50191a51951304165a565b1fdfd368a36 Mon Sep 17 00:00:00 2001 From: Wei Chen Date: Thu, 14 Nov 2019 17:52:01 -0800 Subject: [PATCH] [Relay][Pass] Add pass to remove unused functions in relay module (#4334) * [Relay][Pass] Add pass to remove unused functions in relay module * Add tests * Fix lint * Fix visit order * Add pass argument * Fix --- python/tvm/relay/transform.py | 16 +++ src/relay/backend/vm/compiler.cc | 3 + src/relay/backend/vm/removed_unused_funcs.cc | 134 ++++++++++++++++++ .../test_pass_remove_unused_functions.py | 75 ++++++++++ 4 files changed, 228 insertions(+) create mode 100644 src/relay/backend/vm/removed_unused_funcs.cc create mode 100644 tests/python/relay/test_pass_remove_unused_functions.py diff --git a/python/tvm/relay/transform.py b/python/tvm/relay/transform.py index d3509dabddf99..0a7512a77d1a8 100644 --- a/python/tvm/relay/transform.py +++ b/python/tvm/relay/transform.py @@ -297,6 +297,22 @@ def BackwardFoldScaleAxis(): """ return _transform.BackwardFoldScaleAxis() +def RemoveUnusedFunctions(entry_functions=None): + """Remove unused global relay functions in a relay module. + + Parameters + ---------- + entry_functions: list[string] + The set of entry functions to start from. + + Returns + ------- + ret : tvm.relay.Pass + The registered pass to remove unused functions. + """ + if entry_functions is None: + entry_functions = ['main'] + return _transform.RemoveUnusedFunctions(entry_functions) def ForwardFoldScaleAxis(): """Fold the scaling of axis into weights of conv2d/dense. diff --git a/src/relay/backend/vm/compiler.cc b/src/relay/backend/vm/compiler.cc index cbb8b98409eae..321304226972f 100644 --- a/src/relay/backend/vm/compiler.cc +++ b/src/relay/backend/vm/compiler.cc @@ -54,6 +54,7 @@ namespace transform { Pass LambdaLift(); Pass InlinePrimitives(); +Pass RemoveUnusedFunctions(Array entry_functions); Pass ManifestAlloc(Target target_host) { auto f = tvm::runtime::Registry::Get("relay.transform.ManifestAlloc"); @@ -864,6 +865,8 @@ void VMCompiler::Compile(Module mod, Module VMCompiler::OptimizeModule(const Module& mod, const TargetsMap& targets) { Array pass_seqs; + Array entry_functions{tvm::Expr{"main"}}; + pass_seqs.push_back(transform::RemoveUnusedFunctions(entry_functions)); // Run all dialect legalization passes. pass_seqs.push_back(relay::qnn::transform::Legalize()); diff --git a/src/relay/backend/vm/removed_unused_funcs.cc b/src/relay/backend/vm/removed_unused_funcs.cc new file mode 100644 index 0000000000000..a01204077c556 --- /dev/null +++ b/src/relay/backend/vm/removed_unused_funcs.cc @@ -0,0 +1,134 @@ +/* + * 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. + */ + +/*! + * Copyright (c) 2019 by Contributors + * \file tvm/relay/backend/vm/remove_unused_funcs.cc + * \brief Remove unused global relay functions in a relay module. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +namespace tvm { +namespace relay { +namespace vm { + +/** + * \brief Detects all the functions that can be possibly called by entry function. + */ +struct CallTracer : ExprVisitor { + Module module_; + + // Record the names of all encountered functions + std::unordered_set called_funcs_; + + // Record the expressions that are being visited + std::unordered_set visiting_; + + explicit CallTracer(const Module& module) + : module_{module}, + called_funcs_{}, + visiting_{} {} + + void VisitExpr_(const CallNode* call_node) final { + Expr op = call_node->op; + for (auto param : call_node->args) { + VisitExpr(param); + } + if (auto func_node = op.as()) { + auto func = GetRef(func_node); + auto it = visiting_.find(func); + if (it != visiting_.end()) { + return; + } + visiting_.insert(func); + VisitExpr(func); + } else if (auto global = op.as()) { + called_funcs_.insert(global->name_hint); + auto func = module_->Lookup(global->name_hint); + auto it = visiting_.find(func); + if (it != visiting_.end()) { + return; + } + visiting_.insert(func); + VisitExpr(func); + } + } + + std::unordered_set Trace(const std::string& entry) { + called_funcs_.insert(entry); + auto main_func = module_->Lookup(entry); + VisitExpr(main_func); + return called_funcs_; + } +}; + +/*! + * \brief Remove functions that are not used. + * + * \param module The Relay module. + * \param entry_funcs The set of functions that can be entry function. + * + * \return The module with dead functions removed. + */ +Module RemoveUnusedFunctions(const Module& module, + Array entry_funcs) { + std::unordered_set called_funcs{}; + for (auto entry : entry_funcs) { + auto* str_name = entry.as(); + auto funcs = CallTracer(module).Trace(str_name->value); + called_funcs.insert(funcs.cbegin(), funcs.cend()); + } + auto existing_functions = module->functions; + for (auto f : existing_functions) { + auto it = called_funcs.find(f.first->name_hint); + if (it == called_funcs.end()) { + module->Remove(f.first); + } + } + return module; +} + +} // namespace vm + +namespace transform { + +Pass RemoveUnusedFunctions(Array entry_functions) { + runtime::TypedPackedFunc pass_func = + [=](Module m, PassContext pc) { + return relay::vm::RemoveUnusedFunctions(m, entry_functions); + }; + return CreateModulePass(pass_func, 1, "RemoveUnusedFunctions", {}); +} + +TVM_REGISTER_API("relay._transform.RemoveUnusedFunctions") +.set_body_typed(RemoveUnusedFunctions); + +} // namespace transform + +} // namespace relay +} // namespace tvm diff --git a/tests/python/relay/test_pass_remove_unused_functions.py b/tests/python/relay/test_pass_remove_unused_functions.py new file mode 100644 index 0000000000000..c4a0c41bfdd16 --- /dev/null +++ b/tests/python/relay/test_pass_remove_unused_functions.py @@ -0,0 +1,75 @@ +# 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. +import tvm +from tvm import relay +from tvm.relay import transform +from tvm.relay.prelude import Prelude + +def test_remove_all_prelude_functions(): + mod = relay.Module() + p = Prelude(mod) + x = relay.var("x", shape=(1, 16)) + mod["main"] = relay.Function([x], x) + mod = relay.transform.RemoveUnusedFunctions()(mod) + l = set([x[0].name_hint for x in mod.functions.items()]) + assert l == set(['main']) + +def test_remove_all_prelude_functions_but_referenced_functions(): + mod = relay.Module() + p = Prelude(mod) + x = relay.var("x", shape=(1, 16)) + id_func = relay.Function([x], x) + id_name = relay.GlobalVar('id_func') + mod[id_name] = id_func + + mod["main"] = relay.Function([x], id_name(x)) + mod = relay.transform.RemoveUnusedFunctions()(mod) + l = set([x[0].name_hint for x in mod.functions.items()]) + assert l == set(['id_func', 'main']) + +def test_keep_only_referenced_prelude_functions(): + mod = relay.Module() + p = Prelude(mod) + l = p.nil() + for i in [4, 3, 2, 1, 0]: + l = p.cons(relay.const(i), l) + body = p.hd(p.tl(p.tl(l))) + mod["main"] = relay.Function([], body) + mod = relay.transform.RemoveUnusedFunctions()(mod) + l = set([x[0].name_hint for x in mod.functions.items()]) + assert l == set(['tl', 'hd', 'main']) + +def test_multiple_entry_functions(): + mod = relay.Module() + p = Prelude(mod) + l = p.nil() + for i in [4, 3, 2, 1, 0]: + l = p.cons(relay.const(i), l) + body = p.hd(p.tl(p.tl(l))) + mod["main1"] = relay.Function([], body) + + x = relay.var("x", shape=(1, 16)) + id_func = relay.Function([x], x) + id_name = relay.GlobalVar('id_func') + mod[id_name] = id_func + mod["main2"] = relay.Function([x], id_name(x)) + mod = relay.transform.RemoveUnusedFunctions(['main1', 'main2'])(mod) + l = set([x[0].name_hint for x in mod.functions.items()]) + assert l == set(['tl', 'hd', 'main2', 'id_func', 'main1']) + +if __name__ == '__main__': + pytest.main()