| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * 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 "ssa_type_propagation.h" |
| |
| #include "nodes.h" |
| |
| namespace art { |
| |
| static Primitive::Type MergeTypes(Primitive::Type existing, Primitive::Type new_type) { |
| // We trust the verifier has already done the necessary checking. |
| switch (existing) { |
| case Primitive::kPrimFloat: |
| case Primitive::kPrimDouble: |
| case Primitive::kPrimNot: |
| return existing; |
| default: |
| return new_type; |
| } |
| } |
| |
| // Re-compute and update the type of the instruction. Returns |
| // whether or not the type was changed. |
| static bool UpdateType(HPhi* phi) { |
| Primitive::Type existing = phi->GetType(); |
| |
| Primitive::Type new_type = Primitive::kPrimVoid; |
| for (size_t i = 0, e = phi->InputCount(); i < e; ++i) { |
| Primitive::Type input_type = phi->InputAt(i)->GetType(); |
| new_type = MergeTypes(new_type, input_type); |
| } |
| phi->SetType(new_type); |
| return existing != new_type; |
| } |
| |
| void SsaTypePropagation::Run() { |
| for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) { |
| VisitBasicBlock(it.Current()); |
| } |
| ProcessWorklist(); |
| } |
| |
| void SsaTypePropagation::VisitBasicBlock(HBasicBlock* block) { |
| if (block->IsLoopHeader()) { |
| for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) { |
| HPhi* phi = it.Current()->AsPhi(); |
| // Set the initial type for the phi. Use the non back edge input for reaching |
| // a fixed point faster. |
| phi->SetType(phi->InputAt(0)->GetType()); |
| AddToWorklist(phi); |
| } |
| } else { |
| for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) { |
| HPhi* phi = it.Current()->AsPhi(); |
| if (UpdateType(phi)) { |
| AddDependentInstructionsToWorklist(phi); |
| } |
| } |
| } |
| } |
| |
| void SsaTypePropagation::ProcessWorklist() { |
| while (!worklist_.IsEmpty()) { |
| HPhi* instruction = worklist_.Pop(); |
| if (UpdateType(instruction)) { |
| AddDependentInstructionsToWorklist(instruction); |
| } |
| } |
| } |
| |
| void SsaTypePropagation::AddToWorklist(HPhi* instruction) { |
| worklist_.Add(instruction); |
| } |
| |
| void SsaTypePropagation::AddDependentInstructionsToWorklist(HPhi* instruction) { |
| for (HUseIterator<HInstruction> it(instruction->GetUses()); !it.Done(); it.Advance()) { |
| HPhi* phi = it.Current()->GetUser()->AsPhi(); |
| if (phi != nullptr) { |
| AddToWorklist(phi); |
| } |
| } |
| } |
| |
| } // namespace art |