| // Copyright (c) 2021 ZHOU He |
| // |
| // 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. |
| |
| #include "remove_unused_interface_variables_pass.h" |
| #include "source/spirv_constant.h" |
| namespace spvtools { |
| namespace opt { |
| |
| class RemoveUnusedInterfaceVariablesContext { |
| RemoveUnusedInterfaceVariablesPass& parent_; |
| Instruction& entry_; |
| std::unordered_set<uint32_t> used_variables_; |
| IRContext::ProcessFunction pfn_ = |
| std::bind(&RemoveUnusedInterfaceVariablesContext::processFunction, this, |
| std::placeholders::_1); |
| |
| bool processFunction(Function* func) { |
| for (const auto& basic_block : *func) |
| for (const auto& instruction : basic_block) |
| instruction.ForEachInId([&](const uint32_t* id) { |
| if (used_variables_.count(*id)) return; |
| auto* var = parent_.get_def_use_mgr()->GetDef(*id); |
| if (!var || var->opcode() != spv::Op::OpVariable) return; |
| auto storage_class = |
| spv::StorageClass(var->GetSingleWordInOperand(0)); |
| if (storage_class != spv::StorageClass::Function && |
| (parent_.get_module()->version() >= |
| SPV_SPIRV_VERSION_WORD(1, 4) || |
| storage_class == spv::StorageClass::Input || |
| storage_class == spv::StorageClass::Output)) |
| used_variables_.insert(*id); |
| }); |
| return false; |
| } |
| |
| public: |
| RemoveUnusedInterfaceVariablesContext( |
| RemoveUnusedInterfaceVariablesPass& parent, Instruction& entry) |
| : parent_(parent), entry_(entry) {} |
| |
| void CollectUsedVariables() { |
| std::queue<uint32_t> roots; |
| roots.push(entry_.GetSingleWordInOperand(1)); |
| parent_.context()->ProcessCallTreeFromRoots(pfn_, &roots); |
| } |
| |
| bool ShouldModify() { |
| std::unordered_set<uint32_t> old_variables; |
| for (int i = entry_.NumInOperands() - 1; i >= 3; --i) { |
| auto variable = entry_.GetInOperand(i).words[0]; |
| if (!used_variables_.count(variable)) return true; // It is unused. |
| if (old_variables.count(variable)) return true; // It is duplicate. |
| old_variables.insert(variable); |
| } |
| if (old_variables.size() != used_variables_.size()) // Missing IDs. |
| return true; |
| return false; |
| } |
| |
| void Modify() { |
| for (int i = entry_.NumInOperands() - 1; i >= 3; --i) |
| entry_.RemoveInOperand(i); |
| for (auto id : used_variables_) { |
| entry_.AddOperand(Operand(SPV_OPERAND_TYPE_ID, {id})); |
| } |
| } |
| }; |
| |
| RemoveUnusedInterfaceVariablesPass::Status |
| RemoveUnusedInterfaceVariablesPass::Process() { |
| bool modified = false; |
| for (auto& entry : get_module()->entry_points()) { |
| RemoveUnusedInterfaceVariablesContext context(*this, entry); |
| context.CollectUsedVariables(); |
| if (context.ShouldModify()) { |
| context.Modify(); |
| modified = true; |
| } |
| } |
| return (modified ? Status::SuccessWithChange : Status::SuccessWithoutChange); |
| } |
| } // namespace opt |
| } // namespace spvtools |