| // Copyright (c) 2019 Google LLC. |
| // |
| // 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 "source/opt/split_invalid_unreachable_pass.h" |
| |
| #include "source/opt/ir_builder.h" |
| #include "source/opt/ir_context.h" |
| |
| namespace spvtools { |
| namespace opt { |
| |
| Pass::Status SplitInvalidUnreachablePass::Process() { |
| bool changed = false; |
| std::unordered_set<uint32_t> entry_points; |
| for (auto entry_point : context()->module()->entry_points()) { |
| entry_points.insert(entry_point.GetSingleWordOperand(1)); |
| } |
| |
| for (auto func = context()->module()->begin(); |
| func != context()->module()->end(); ++func) { |
| if (entry_points.find(func->result_id()) == entry_points.end()) continue; |
| std::unordered_set<uint32_t> continue_targets; |
| std::unordered_set<uint32_t> merge_blocks; |
| std::unordered_set<BasicBlock*> unreachable_blocks; |
| for (auto block = func->begin(); block != func->end(); ++block) { |
| unreachable_blocks.insert(&*block); |
| uint32_t continue_target = block->ContinueBlockIdIfAny(); |
| if (continue_target != 0) continue_targets.insert(continue_target); |
| uint32_t merge_block = block->MergeBlockIdIfAny(); |
| if (merge_block != 0) merge_blocks.insert(merge_block); |
| } |
| |
| cfg()->ForEachBlockInPostOrder( |
| func->entry().get(), [&unreachable_blocks](BasicBlock* inner_block) { |
| unreachable_blocks.erase(inner_block); |
| }); |
| |
| for (auto unreachable : unreachable_blocks) { |
| uint32_t block_id = unreachable->id(); |
| if (continue_targets.find(block_id) == continue_targets.end() || |
| merge_blocks.find(block_id) == merge_blocks.end()) { |
| continue; |
| } |
| |
| std::vector<std::tuple<Instruction*, uint32_t>> usages; |
| context()->get_def_use_mgr()->ForEachUse( |
| unreachable->GetLabelInst(), |
| [&usages](Instruction* use, uint32_t idx) { |
| if ((use->opcode() == SpvOpLoopMerge && idx == 0) || |
| use->opcode() == SpvOpSelectionMerge) { |
| usages.push_back(std::make_pair(use, idx)); |
| } |
| }); |
| |
| for (auto usage : usages) { |
| Instruction* use; |
| uint32_t idx; |
| std::tie(use, idx) = usage; |
| uint32_t new_id = context()->TakeNextId(); |
| std::unique_ptr<Instruction> new_label( |
| new Instruction(context(), SpvOpLabel, 0, new_id, {})); |
| get_def_use_mgr()->AnalyzeInstDefUse(new_label.get()); |
| std::unique_ptr<BasicBlock> new_block( |
| new BasicBlock(std::move(new_label))); |
| auto* block_ptr = new_block.get(); |
| InstructionBuilder builder(context(), new_block.get(), |
| IRContext::kAnalysisDefUse | |
| IRContext::kAnalysisInstrToBlockMapping); |
| builder.AddUnreachable(); |
| cfg()->RegisterBlock(block_ptr); |
| (&*func)->InsertBasicBlockBefore(std::move(new_block), unreachable); |
| use->SetInOperand(0, {new_id}); |
| get_def_use_mgr()->UpdateDefUse(use); |
| cfg()->AddEdges(block_ptr); |
| changed = true; |
| } |
| } |
| } |
| |
| return changed ? Status::SuccessWithChange : Status::SuccessWithoutChange; |
| } |
| |
| } // namespace opt |
| } // namespace spvtools |