| // 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 "eliminate_dead_functions_util.h" |
| |
| namespace spvtools { |
| namespace opt { |
| |
| namespace eliminatedeadfunctionsutil { |
| |
| Module::iterator EliminateFunction(IRContext* context, |
| Module::iterator* func_iter) { |
| bool first_func = *func_iter == context->module()->begin(); |
| bool seen_func_end = false; |
| std::unordered_set<Instruction*> to_kill; |
| (*func_iter) |
| ->ForEachInst( |
| [context, first_func, func_iter, &seen_func_end, |
| &to_kill](Instruction* inst) { |
| if (inst->opcode() == spv::Op::OpFunctionEnd) { |
| seen_func_end = true; |
| } |
| // Move non-semantic instructions to the previous function or |
| // global values if this is the first function. |
| if (seen_func_end && inst->opcode() == spv::Op::OpExtInst) { |
| assert(inst->IsNonSemanticInstruction()); |
| if (to_kill.find(inst) != to_kill.end()) return; |
| std::unique_ptr<Instruction> clone(inst->Clone(context)); |
| context->ForgetUses(inst); |
| context->AnalyzeDefUse(clone.get()); |
| if (first_func) { |
| context->AddGlobalValue(std::move(clone)); |
| } else { |
| auto prev_func_iter = *func_iter; |
| --prev_func_iter; |
| prev_func_iter->AddNonSemanticInstruction(std::move(clone)); |
| } |
| inst->ToNop(); |
| } else if (to_kill.find(inst) == to_kill.end()) { |
| context->CollectNonSemanticTree(inst, &to_kill); |
| context->KillInst(inst); |
| } |
| }, |
| true, true); |
| |
| for (auto* dead : to_kill) { |
| context->KillInst(dead); |
| } |
| |
| return func_iter->Erase(); |
| } |
| |
| } // namespace eliminatedeadfunctionsutil |
| } // namespace opt |
| } // namespace spvtools |