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https://github.com/KhronosGroup/SPIRV-Tools
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e43c91046b
Creates a pass called eliminate dead functions that looks for functions that could never be called, and deletes them from the module. To support this change a new function was added to the Pass class to traverse the call trees from diffent starting points. Includes a test to ensure that annotations are removed when deleting a dead function. They were not, so fixed that up as well. Did some cleanup of the assembly for the test in pass_test.cpp. Trying to make them smaller and easier to read.
62 lines
1.9 KiB
C++
62 lines
1.9 KiB
C++
// Copyright (c) 2017 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "eliminate_dead_functions_pass.h"
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#include <unordered_set>
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namespace spvtools {
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namespace opt {
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Pass::Status EliminateDeadFunctionsPass::Process(ir::Module* module) {
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bool modified = false;
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module_ = module;
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// Identify live functions first. Those that are not live
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// are dead.
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std::unordered_set<const ir::Function*> live_function_set;
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ProcessFunction mark_live = [&live_function_set](ir::Function* fp) {
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live_function_set.insert(fp);
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return false;
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};
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ProcessReachableCallTree(mark_live, module);
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def_use_mgr_.reset(new analysis::DefUseManager(consumer(), module));
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FindNamedOrDecoratedIds();
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for (auto funcIter = module->begin(); funcIter != module->end();) {
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if (live_function_set.count(&*funcIter) == 0) {
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modified = true;
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EliminateFunction(&*funcIter);
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funcIter = funcIter.Erase();
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} else {
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++funcIter;
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}
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}
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return modified ? Pass::Status::SuccessWithChange
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: Pass::Status::SuccessWithoutChange;
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}
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void EliminateDeadFunctionsPass::EliminateFunction(ir::Function* func) {
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// Remove all of the instruction in the function body
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func->ForEachInst(
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[this](ir::Instruction* inst) {
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KillNamesAndDecorates(inst);
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def_use_mgr_->KillInst(inst);
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},
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true);
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}
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} // namespace opt
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} // namespace spvtools
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