mirror of
https://github.com/KhronosGroup/SPIRV-Tools
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c4c6f2ba5c
This PR adds a generic dataflow analysis framework to SPIRV-opt, with the intent of being used in SPIRV-lint. This may also be useful for SPIRV-opt, as existing ad-hoc analyses can be rewritten to use a common framework, but this is not the target of this PR.
92 lines
2.8 KiB
C++
92 lines
2.8 KiB
C++
// Copyright (c) 2021 Google LLC.
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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 "source/opt/dataflow.h"
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#include <algorithm>
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#include <cstdint>
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namespace spvtools {
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namespace opt {
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bool DataFlowAnalysis::Enqueue(Instruction* inst) {
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bool& is_enqueued = on_worklist_[inst];
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if (is_enqueued) return false;
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is_enqueued = true;
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worklist_.push(inst);
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return true;
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}
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DataFlowAnalysis::VisitResult DataFlowAnalysis::RunOnce(
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Function* function, bool is_first_iteration) {
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InitializeWorklist(function, is_first_iteration);
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VisitResult ret = VisitResult::kResultFixed;
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while (!worklist_.empty()) {
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Instruction* top = worklist_.front();
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worklist_.pop();
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on_worklist_[top] = false;
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VisitResult result = Visit(top);
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if (result == VisitResult::kResultChanged) {
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EnqueueSuccessors(top);
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ret = VisitResult::kResultChanged;
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}
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}
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return ret;
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}
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void DataFlowAnalysis::Run(Function* function) {
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VisitResult result = RunOnce(function, true);
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while (result == VisitResult::kResultChanged) {
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result = RunOnce(function, false);
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}
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}
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void ForwardDataFlowAnalysis::InitializeWorklist(Function* function,
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bool /*is_first_iteration*/) {
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context().cfg()->ForEachBlockInReversePostOrder(
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function->entry().get(), [this](BasicBlock* bb) {
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if (label_position_ == LabelPosition::kLabelsOnly) {
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Enqueue(bb->GetLabelInst());
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return;
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}
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if (label_position_ == LabelPosition::kLabelsAtBeginning) {
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Enqueue(bb->GetLabelInst());
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}
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for (Instruction& inst : *bb) {
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Enqueue(&inst);
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}
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if (label_position_ == LabelPosition::kLabelsAtEnd) {
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Enqueue(bb->GetLabelInst());
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}
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});
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}
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void ForwardDataFlowAnalysis::EnqueueUsers(Instruction* inst) {
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context().get_def_use_mgr()->ForEachUser(
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inst, [this](Instruction* user) { Enqueue(user); });
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}
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void ForwardDataFlowAnalysis::EnqueueBlockSuccessors(Instruction* inst) {
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if (inst->opcode() != SpvOpLabel) return;
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context()
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.cfg()
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->block(inst->result_id())
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->ForEachSuccessorLabel([this](uint32_t* label) {
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Enqueue(context().cfg()->block(*label)->GetLabelInst());
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});
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}
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} // namespace opt
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} // namespace spvtools
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