| /* |
| * 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_builder.h" |
| |
| #include "data_type-inl.h" |
| #include "dex/bytecode_utils.h" |
| #include "mirror/class-inl.h" |
| #include "nodes.h" |
| #include "reference_type_propagation.h" |
| #include "scoped_thread_state_change-inl.h" |
| #include "ssa_phi_elimination.h" |
| |
| namespace art { |
| |
| void SsaBuilder::FixNullConstantType() { |
| // The order doesn't matter here. |
| for (HBasicBlock* block : graph_->GetReversePostOrder()) { |
| for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) { |
| HInstruction* equality_instr = it.Current(); |
| if (!equality_instr->IsEqual() && !equality_instr->IsNotEqual()) { |
| continue; |
| } |
| HInstruction* left = equality_instr->InputAt(0); |
| HInstruction* right = equality_instr->InputAt(1); |
| HInstruction* int_operand = nullptr; |
| |
| if ((left->GetType() == DataType::Type::kReference) && |
| (right->GetType() == DataType::Type::kInt32)) { |
| int_operand = right; |
| } else if ((right->GetType() == DataType::Type::kReference) && |
| (left->GetType() == DataType::Type::kInt32)) { |
| int_operand = left; |
| } else { |
| continue; |
| } |
| |
| // If we got here, we are comparing against a reference and the int constant |
| // should be replaced with a null constant. |
| // Both type propagation and redundant phi elimination ensure `int_operand` |
| // can only be the 0 constant. |
| DCHECK(int_operand->IsIntConstant()) << int_operand->DebugName(); |
| DCHECK_EQ(0, int_operand->AsIntConstant()->GetValue()); |
| equality_instr->ReplaceInput(graph_->GetNullConstant(), int_operand == right ? 1 : 0); |
| } |
| } |
| } |
| |
| void SsaBuilder::EquivalentPhisCleanup() { |
| // The order doesn't matter here. |
| for (HBasicBlock* block : graph_->GetReversePostOrder()) { |
| for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) { |
| HPhi* phi = it.Current()->AsPhi(); |
| HPhi* next = phi->GetNextEquivalentPhiWithSameType(); |
| if (next != nullptr) { |
| // Make sure we do not replace a live phi with a dead phi. A live phi |
| // has been handled by the type propagation phase, unlike a dead phi. |
| if (next->IsLive()) { |
| phi->ReplaceWith(next); |
| phi->SetDead(); |
| } else { |
| next->ReplaceWith(phi); |
| } |
| DCHECK(next->GetNextEquivalentPhiWithSameType() == nullptr) |
| << "More then one phi equivalent with type " << phi->GetType() |
| << " found for phi" << phi->GetId(); |
| } |
| } |
| } |
| } |
| |
| void SsaBuilder::FixEnvironmentPhis() { |
| for (HBasicBlock* block : graph_->GetReversePostOrder()) { |
| for (HInstructionIterator it_phis(block->GetPhis()); !it_phis.Done(); it_phis.Advance()) { |
| HPhi* phi = it_phis.Current()->AsPhi(); |
| // If the phi is not dead, or has no environment uses, there is nothing to do. |
| if (!phi->IsDead() || !phi->HasEnvironmentUses()) continue; |
| HInstruction* next = phi->GetNext(); |
| if (!phi->IsVRegEquivalentOf(next)) continue; |
| if (next->AsPhi()->IsDead()) { |
| // If the phi equivalent is dead, check if there is another one. |
| next = next->GetNext(); |
| if (!phi->IsVRegEquivalentOf(next)) continue; |
| // There can be at most two phi equivalents. |
| DCHECK(!phi->IsVRegEquivalentOf(next->GetNext())); |
| if (next->AsPhi()->IsDead()) continue; |
| } |
| // We found a live phi equivalent. Update the environment uses of `phi` with it. |
| phi->ReplaceWith(next); |
| } |
| } |
| } |
| |
| static void AddDependentInstructionsToWorklist(HInstruction* instruction, |
| ScopedArenaVector<HPhi*>* worklist) { |
| // If `instruction` is a dead phi, type conflict was just identified. All its |
| // live phi users, and transitively users of those users, therefore need to be |
| // marked dead/conflicting too, so we add them to the worklist. Otherwise we |
| // add users whose type does not match and needs to be updated. |
| bool add_all_live_phis = instruction->IsPhi() && instruction->AsPhi()->IsDead(); |
| for (const HUseListNode<HInstruction*>& use : instruction->GetUses()) { |
| HInstruction* user = use.GetUser(); |
| if (user->IsPhi() && user->AsPhi()->IsLive()) { |
| if (add_all_live_phis || user->GetType() != instruction->GetType()) { |
| worklist->push_back(user->AsPhi()); |
| } |
| } |
| } |
| } |
| |
| // Find a candidate primitive type for `phi` by merging the type of its inputs. |
| // Return false if conflict is identified. |
| static bool TypePhiFromInputs(HPhi* phi) { |
| DataType::Type common_type = phi->GetType(); |
| |
| for (HInstruction* input : phi->GetInputs()) { |
| if (input->IsPhi() && input->AsPhi()->IsDead()) { |
| // Phis are constructed live so if an input is a dead phi, it must have |
| // been made dead due to type conflict. Mark this phi conflicting too. |
| return false; |
| } |
| |
| DataType::Type input_type = HPhi::ToPhiType(input->GetType()); |
| if (common_type == input_type) { |
| // No change in type. |
| } else if (DataType::Is64BitType(common_type) != DataType::Is64BitType(input_type)) { |
| // Types are of different sizes, e.g. int vs. long. Must be a conflict. |
| return false; |
| } else if (DataType::IsIntegralType(common_type)) { |
| // Previous inputs were integral, this one is not but is of the same size. |
| // This does not imply conflict since some bytecode instruction types are |
| // ambiguous. TypeInputsOfPhi will either type them or detect a conflict. |
| DCHECK(DataType::IsFloatingPointType(input_type) || |
| input_type == DataType::Type::kReference); |
| common_type = input_type; |
| } else if (DataType::IsIntegralType(input_type)) { |
| // Input is integral, common type is not. Same as in the previous case, if |
| // there is a conflict, it will be detected during TypeInputsOfPhi. |
| DCHECK(DataType::IsFloatingPointType(common_type) || |
| common_type == DataType::Type::kReference); |
| } else { |
| // Combining float and reference types. Clearly a conflict. |
| DCHECK( |
| (common_type == DataType::Type::kFloat32 && input_type == DataType::Type::kReference) || |
| (common_type == DataType::Type::kReference && input_type == DataType::Type::kFloat32)); |
| return false; |
| } |
| } |
| |
| // We have found a candidate type for the phi. Set it and return true. We may |
| // still discover conflict whilst typing the individual inputs in TypeInputsOfPhi. |
| phi->SetType(common_type); |
| return true; |
| } |
| |
| // Replace inputs of `phi` to match its type. Return false if conflict is identified. |
| bool SsaBuilder::TypeInputsOfPhi(HPhi* phi, ScopedArenaVector<HPhi*>* worklist) { |
| DataType::Type common_type = phi->GetType(); |
| if (DataType::IsIntegralType(common_type)) { |
| // We do not need to retype ambiguous inputs because they are always constructed |
| // with the integral type candidate. |
| if (kIsDebugBuild) { |
| for (HInstruction* input : phi->GetInputs()) { |
| DCHECK(HPhi::ToPhiType(input->GetType()) == common_type); |
| } |
| } |
| // Inputs did not need to be replaced, hence no conflict. Report success. |
| return true; |
| } else { |
| DCHECK(common_type == DataType::Type::kReference || |
| DataType::IsFloatingPointType(common_type)); |
| HInputsRef inputs = phi->GetInputs(); |
| for (size_t i = 0; i < inputs.size(); ++i) { |
| HInstruction* input = inputs[i]; |
| if (input->GetType() != common_type) { |
| // Input type does not match phi's type. Try to retype the input or |
| // generate a suitably typed equivalent. |
| HInstruction* equivalent = (common_type == DataType::Type::kReference) |
| ? GetReferenceTypeEquivalent(input) |
| : GetFloatOrDoubleEquivalent(input, common_type); |
| if (equivalent == nullptr) { |
| // Input could not be typed. Report conflict. |
| return false; |
| } |
| // Make sure the input did not change its type and we do not need to |
| // update its users. |
| DCHECK_NE(input, equivalent); |
| |
| phi->ReplaceInput(equivalent, i); |
| if (equivalent->IsPhi()) { |
| worklist->push_back(equivalent->AsPhi()); |
| } |
| } |
| } |
| // All inputs either matched the type of the phi or we successfully replaced |
| // them with a suitable equivalent. Report success. |
| return true; |
| } |
| } |
| |
| // Attempt to set the primitive type of `phi` to match its inputs. Return whether |
| // it was changed by the algorithm or not. |
| bool SsaBuilder::UpdatePrimitiveType(HPhi* phi, ScopedArenaVector<HPhi*>* worklist) { |
| DCHECK(phi->IsLive()); |
| DataType::Type original_type = phi->GetType(); |
| |
| // Try to type the phi in two stages: |
| // (1) find a candidate type for the phi by merging types of all its inputs, |
| // (2) try to type the phi's inputs to that candidate type. |
| // Either of these stages may detect a type conflict and fail, in which case |
| // we immediately abort. |
| if (!TypePhiFromInputs(phi) || !TypeInputsOfPhi(phi, worklist)) { |
| // Conflict detected. Mark the phi dead and return true because it changed. |
| phi->SetDead(); |
| return true; |
| } |
| |
| // Return true if the type of the phi has changed. |
| return phi->GetType() != original_type; |
| } |
| |
| void SsaBuilder::RunPrimitiveTypePropagation() { |
| ScopedArenaVector<HPhi*> worklist(local_allocator_->Adapter(kArenaAllocGraphBuilder)); |
| |
| for (HBasicBlock* block : graph_->GetReversePostOrder()) { |
| if (block->IsLoopHeader()) { |
| for (HInstructionIterator phi_it(block->GetPhis()); !phi_it.Done(); phi_it.Advance()) { |
| HPhi* phi = phi_it.Current()->AsPhi(); |
| if (phi->IsLive()) { |
| worklist.push_back(phi); |
| } |
| } |
| } else { |
| for (HInstructionIterator phi_it(block->GetPhis()); !phi_it.Done(); phi_it.Advance()) { |
| // Eagerly compute the type of the phi, for quicker convergence. Note |
| // that we don't need to add users to the worklist because we are |
| // doing a reverse post-order visit, therefore either the phi users are |
| // non-loop phi and will be visited later in the visit, or are loop-phis, |
| // and they are already in the work list. |
| HPhi* phi = phi_it.Current()->AsPhi(); |
| if (phi->IsLive()) { |
| UpdatePrimitiveType(phi, &worklist); |
| } |
| } |
| } |
| } |
| |
| ProcessPrimitiveTypePropagationWorklist(&worklist); |
| EquivalentPhisCleanup(); |
| } |
| |
| void SsaBuilder::ProcessPrimitiveTypePropagationWorklist(ScopedArenaVector<HPhi*>* worklist) { |
| // Process worklist |
| while (!worklist->empty()) { |
| HPhi* phi = worklist->back(); |
| worklist->pop_back(); |
| // The phi could have been made dead as a result of conflicts while in the |
| // worklist. If it is now dead, there is no point in updating its type. |
| if (phi->IsLive() && UpdatePrimitiveType(phi, worklist)) { |
| AddDependentInstructionsToWorklist(phi, worklist); |
| } |
| } |
| } |
| |
| static HArrayGet* FindFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) { |
| DataType::Type type = aget->GetType(); |
| DCHECK(DataType::IsIntOrLongType(type)); |
| HInstruction* next = aget->GetNext(); |
| if (next != nullptr && next->IsArrayGet()) { |
| HArrayGet* next_aget = next->AsArrayGet(); |
| if (next_aget->IsEquivalentOf(aget)) { |
| return next_aget; |
| } |
| } |
| return nullptr; |
| } |
| |
| static HArrayGet* CreateFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) { |
| DataType::Type type = aget->GetType(); |
| DCHECK(DataType::IsIntOrLongType(type)); |
| DCHECK(FindFloatOrDoubleEquivalentOfArrayGet(aget) == nullptr); |
| |
| HArrayGet* equivalent = new (aget->GetBlock()->GetGraph()->GetAllocator()) HArrayGet( |
| aget->GetArray(), |
| aget->GetIndex(), |
| type == DataType::Type::kInt32 ? DataType::Type::kFloat32 : DataType::Type::kFloat64, |
| aget->GetDexPc()); |
| aget->GetBlock()->InsertInstructionAfter(equivalent, aget); |
| return equivalent; |
| } |
| |
| static DataType::Type GetPrimitiveArrayComponentType(HInstruction* array) |
| REQUIRES_SHARED(Locks::mutator_lock_) { |
| ReferenceTypeInfo array_type = array->GetReferenceTypeInfo(); |
| DCHECK(array_type.IsPrimitiveArrayClass()); |
| return DataTypeFromPrimitive( |
| array_type.GetTypeHandle()->GetComponentType()->GetPrimitiveType()); |
| } |
| |
| bool SsaBuilder::FixAmbiguousArrayOps() { |
| if (ambiguous_agets_.empty() && ambiguous_asets_.empty()) { |
| return true; |
| } |
| |
| // The wrong ArrayGet equivalent may still have Phi uses coming from ArraySet |
| // uses (because they are untyped) and environment uses (if --debuggable). |
| // After resolving all ambiguous ArrayGets, we will re-run primitive type |
| // propagation on the Phis which need to be updated. |
| ScopedArenaVector<HPhi*> worklist(local_allocator_->Adapter(kArenaAllocGraphBuilder)); |
| |
| { |
| ScopedObjectAccess soa(Thread::Current()); |
| |
| for (HArrayGet* aget_int : ambiguous_agets_) { |
| HInstruction* array = aget_int->GetArray(); |
| if (!array->GetReferenceTypeInfo().IsPrimitiveArrayClass()) { |
| // RTP did not type the input array. Bail. |
| VLOG(compiler) << "Not compiled: Could not infer an array type for array operation at " |
| << aget_int->GetDexPc(); |
| return false; |
| } |
| |
| HArrayGet* aget_float = FindFloatOrDoubleEquivalentOfArrayGet(aget_int); |
| DataType::Type array_type = GetPrimitiveArrayComponentType(array); |
| DCHECK_EQ(DataType::Is64BitType(aget_int->GetType()), DataType::Is64BitType(array_type)); |
| |
| if (DataType::IsIntOrLongType(array_type)) { |
| if (aget_float != nullptr) { |
| // There is a float/double equivalent. We must replace it and re-run |
| // primitive type propagation on all dependent instructions. |
| aget_float->ReplaceWith(aget_int); |
| aget_float->GetBlock()->RemoveInstruction(aget_float); |
| AddDependentInstructionsToWorklist(aget_int, &worklist); |
| } |
| } else { |
| DCHECK(DataType::IsFloatingPointType(array_type)); |
| if (aget_float == nullptr) { |
| // This is a float/double ArrayGet but there were no typed uses which |
| // would create the typed equivalent. Create it now. |
| aget_float = CreateFloatOrDoubleEquivalentOfArrayGet(aget_int); |
| } |
| // Replace the original int/long instruction. Note that it may have phi |
| // uses, environment uses, as well as real uses (from untyped ArraySets). |
| // We need to re-run primitive type propagation on its dependent instructions. |
| aget_int->ReplaceWith(aget_float); |
| aget_int->GetBlock()->RemoveInstruction(aget_int); |
| AddDependentInstructionsToWorklist(aget_float, &worklist); |
| } |
| } |
| |
| // Set a flag stating that types of ArrayGets have been resolved. Requesting |
| // equivalent of the wrong type with GetFloatOrDoubleEquivalentOfArrayGet |
| // will fail from now on. |
| agets_fixed_ = true; |
| |
| for (HArraySet* aset : ambiguous_asets_) { |
| HInstruction* array = aset->GetArray(); |
| if (!array->GetReferenceTypeInfo().IsPrimitiveArrayClass()) { |
| // RTP did not type the input array. Bail. |
| VLOG(compiler) << "Not compiled: Could not infer an array type for array operation at " |
| << aset->GetDexPc(); |
| return false; |
| } |
| |
| HInstruction* value = aset->GetValue(); |
| DataType::Type value_type = value->GetType(); |
| DataType::Type array_type = GetPrimitiveArrayComponentType(array); |
| DCHECK_EQ(DataType::Is64BitType(value_type), DataType::Is64BitType(array_type)); |
| |
| if (DataType::IsFloatingPointType(array_type)) { |
| if (!DataType::IsFloatingPointType(value_type)) { |
| DCHECK(DataType::IsIntegralType(value_type)); |
| // Array elements are floating-point but the value has not been replaced |
| // with its floating-point equivalent. The replacement must always |
| // succeed in code validated by the verifier. |
| HInstruction* equivalent = GetFloatOrDoubleEquivalent(value, array_type); |
| DCHECK(equivalent != nullptr); |
| aset->ReplaceInput(equivalent, /* input_index */ 2); |
| if (equivalent->IsPhi()) { |
| // Returned equivalent is a phi which may not have had its inputs |
| // replaced yet. We need to run primitive type propagation on it. |
| worklist.push_back(equivalent->AsPhi()); |
| } |
| } |
| // Refine the side effects of this floating point aset. Note that we do this even if |
| // no replacement occurs, since the right-hand-side may have been corrected already. |
| aset->SetSideEffects(HArraySet::ComputeSideEffects(aset->GetComponentType())); |
| } else { |
| // Array elements are integral and the value assigned to it initially |
| // was integral too. Nothing to do. |
| DCHECK(DataType::IsIntegralType(array_type)); |
| DCHECK(DataType::IsIntegralType(value_type)); |
| } |
| } |
| } |
| |
| if (!worklist.empty()) { |
| ProcessPrimitiveTypePropagationWorklist(&worklist); |
| EquivalentPhisCleanup(); |
| } |
| |
| return true; |
| } |
| |
| static bool HasAliasInEnvironments(HInstruction* instruction) { |
| HEnvironment* last_user = nullptr; |
| for (const HUseListNode<HEnvironment*>& use : instruction->GetEnvUses()) { |
| DCHECK(use.GetUser() != nullptr); |
| // Note: The first comparison (== null) always fails. |
| if (use.GetUser() == last_user) { |
| return true; |
| } |
| last_user = use.GetUser(); |
| } |
| |
| if (kIsDebugBuild) { |
| // Do a quadratic search to ensure same environment uses are next |
| // to each other. |
| const HUseList<HEnvironment*>& env_uses = instruction->GetEnvUses(); |
| for (auto current = env_uses.begin(), end = env_uses.end(); current != end; ++current) { |
| auto next = current; |
| for (++next; next != end; ++next) { |
| DCHECK(next->GetUser() != current->GetUser()); |
| } |
| } |
| } |
| return false; |
| } |
| |
| void SsaBuilder::RemoveRedundantUninitializedStrings() { |
| if (graph_->IsDebuggable()) { |
| // Do not perform the optimization for consistency with the interpreter |
| // which always allocates an object for new-instance of String. |
| return; |
| } |
| |
| for (HNewInstance* new_instance : uninitialized_strings_) { |
| DCHECK(new_instance->IsInBlock()); |
| DCHECK(new_instance->IsStringAlloc()); |
| |
| // Replace NewInstance of String with NullConstant if not used prior to |
| // calling StringFactory. In case of deoptimization, the interpreter is |
| // expected to skip null check on the `this` argument of the StringFactory call. |
| if (!new_instance->HasNonEnvironmentUses() && !HasAliasInEnvironments(new_instance)) { |
| new_instance->ReplaceWith(graph_->GetNullConstant()); |
| new_instance->GetBlock()->RemoveInstruction(new_instance); |
| |
| // Remove LoadClass if not needed any more. |
| HInstruction* input = new_instance->InputAt(0); |
| HLoadClass* load_class = nullptr; |
| |
| // If the class was not present in the dex cache at the point of building |
| // the graph, the builder inserted a HClinitCheck in between. Since the String |
| // class is always initialized at the point of running Java code, we can remove |
| // that check. |
| if (input->IsClinitCheck()) { |
| load_class = input->InputAt(0)->AsLoadClass(); |
| input->ReplaceWith(load_class); |
| input->GetBlock()->RemoveInstruction(input); |
| } else { |
| load_class = input->AsLoadClass(); |
| DCHECK(new_instance->IsStringAlloc()); |
| DCHECK(!load_class->NeedsAccessCheck()) << "String class is always accessible"; |
| } |
| DCHECK(load_class != nullptr); |
| if (!load_class->HasUses()) { |
| // Even if the HLoadClass needs access check, we can remove it, as we know the |
| // String class does not need it. |
| load_class->GetBlock()->RemoveInstruction(load_class); |
| } |
| } |
| } |
| } |
| |
| GraphAnalysisResult SsaBuilder::BuildSsa() { |
| DCHECK(!graph_->IsInSsaForm()); |
| |
| // 1) Propagate types of phis. At this point, phis are typed void in the general |
| // case, or float/double/reference if we created an equivalent phi. So we need |
| // to propagate the types across phis to give them a correct type. If a type |
| // conflict is detected in this stage, the phi is marked dead. |
| RunPrimitiveTypePropagation(); |
| |
| // 2) Now that the correct primitive types have been assigned, we can get rid |
| // of redundant phis. Note that we cannot do this phase before type propagation, |
| // otherwise we could get rid of phi equivalents, whose presence is a requirement |
| // for the type propagation phase. Note that this is to satisfy statement (a) |
| // of the SsaBuilder (see ssa_builder.h). |
| SsaRedundantPhiElimination(graph_).Run(); |
| |
| // 3) Fix the type for null constants which are part of an equality comparison. |
| // We need to do this after redundant phi elimination, to ensure the only cases |
| // that we can see are reference comparison against 0. The redundant phi |
| // elimination ensures we do not see a phi taking two 0 constants in a HEqual |
| // or HNotEqual. |
| FixNullConstantType(); |
| |
| // 4) Compute type of reference type instructions. The pass assumes that |
| // NullConstant has been fixed up. |
| ReferenceTypePropagation(graph_, |
| class_loader_, |
| dex_cache_, |
| handles_, |
| /* is_first_run */ true).Run(); |
| |
| // 5) HInstructionBuilder duplicated ArrayGet instructions with ambiguous type |
| // (int/float or long/double) and marked ArraySets with ambiguous input type. |
| // Now that RTP computed the type of the array input, the ambiguity can be |
| // resolved and the correct equivalents kept. |
| if (!FixAmbiguousArrayOps()) { |
| return kAnalysisFailAmbiguousArrayOp; |
| } |
| |
| // 6) Mark dead phis. This will mark phis which are not used by instructions |
| // or other live phis. If compiling as debuggable code, phis will also be kept |
| // live if they have an environment use. |
| SsaDeadPhiElimination dead_phi_elimimation(graph_); |
| dead_phi_elimimation.MarkDeadPhis(); |
| |
| // 7) Make sure environments use the right phi equivalent: a phi marked dead |
| // can have a phi equivalent that is not dead. In that case we have to replace |
| // it with the live equivalent because deoptimization and try/catch rely on |
| // environments containing values of all live vregs at that point. Note that |
| // there can be multiple phis for the same Dex register that are live |
| // (for example when merging constants), in which case it is okay for the |
| // environments to just reference one. |
| FixEnvironmentPhis(); |
| |
| // 8) Now that the right phis are used for the environments, we can eliminate |
| // phis we do not need. Regardless of the debuggable status, this phase is |
| /// necessary for statement (b) of the SsaBuilder (see ssa_builder.h), as well |
| // as for the code generation, which does not deal with phis of conflicting |
| // input types. |
| dead_phi_elimimation.EliminateDeadPhis(); |
| |
| // 9) HInstructionBuidler replaced uses of NewInstances of String with the |
| // results of their corresponding StringFactory calls. Unless the String |
| // objects are used before they are initialized, they can be replaced with |
| // NullConstant. Note that this optimization is valid only if unsimplified |
| // code does not use the uninitialized value because we assume execution can |
| // be deoptimized at any safepoint. We must therefore perform it before any |
| // other optimizations. |
| RemoveRedundantUninitializedStrings(); |
| |
| graph_->SetInSsaForm(); |
| return kAnalysisSuccess; |
| } |
| |
| /** |
| * Constants in the Dex format are not typed. So the builder types them as |
| * integers, but when doing the SSA form, we might realize the constant |
| * is used for floating point operations. We create a floating-point equivalent |
| * constant to make the operations correctly typed. |
| */ |
| HFloatConstant* SsaBuilder::GetFloatEquivalent(HIntConstant* constant) { |
| // We place the floating point constant next to this constant. |
| HFloatConstant* result = constant->GetNext()->AsFloatConstant(); |
| if (result == nullptr) { |
| float value = bit_cast<float, int32_t>(constant->GetValue()); |
| result = new (graph_->GetAllocator()) HFloatConstant(value); |
| constant->GetBlock()->InsertInstructionBefore(result, constant->GetNext()); |
| graph_->CacheFloatConstant(result); |
| } else { |
| // If there is already a constant with the expected type, we know it is |
| // the floating point equivalent of this constant. |
| DCHECK_EQ((bit_cast<int32_t, float>(result->GetValue())), constant->GetValue()); |
| } |
| return result; |
| } |
| |
| /** |
| * Wide constants in the Dex format are not typed. So the builder types them as |
| * longs, but when doing the SSA form, we might realize the constant |
| * is used for floating point operations. We create a floating-point equivalent |
| * constant to make the operations correctly typed. |
| */ |
| HDoubleConstant* SsaBuilder::GetDoubleEquivalent(HLongConstant* constant) { |
| // We place the floating point constant next to this constant. |
| HDoubleConstant* result = constant->GetNext()->AsDoubleConstant(); |
| if (result == nullptr) { |
| double value = bit_cast<double, int64_t>(constant->GetValue()); |
| result = new (graph_->GetAllocator()) HDoubleConstant(value); |
| constant->GetBlock()->InsertInstructionBefore(result, constant->GetNext()); |
| graph_->CacheDoubleConstant(result); |
| } else { |
| // If there is already a constant with the expected type, we know it is |
| // the floating point equivalent of this constant. |
| DCHECK_EQ((bit_cast<int64_t, double>(result->GetValue())), constant->GetValue()); |
| } |
| return result; |
| } |
| |
| /** |
| * Because of Dex format, we might end up having the same phi being |
| * used for non floating point operations and floating point / reference operations. |
| * Because we want the graph to be correctly typed (and thereafter avoid moves between |
| * floating point registers and core registers), we need to create a copy of the |
| * phi with a floating point / reference type. |
| */ |
| HPhi* SsaBuilder::GetFloatDoubleOrReferenceEquivalentOfPhi(HPhi* phi, DataType::Type type) { |
| DCHECK(phi->IsLive()) << "Cannot get equivalent of a dead phi since it would create a live one."; |
| |
| // We place the floating point /reference phi next to this phi. |
| HInstruction* next = phi->GetNext(); |
| if (next != nullptr |
| && next->AsPhi()->GetRegNumber() == phi->GetRegNumber() |
| && next->GetType() != type) { |
| // Move to the next phi to see if it is the one we are looking for. |
| next = next->GetNext(); |
| } |
| |
| if (next == nullptr |
| || (next->AsPhi()->GetRegNumber() != phi->GetRegNumber()) |
| || (next->GetType() != type)) { |
| ArenaAllocator* allocator = graph_->GetAllocator(); |
| HInputsRef inputs = phi->GetInputs(); |
| HPhi* new_phi = new (allocator) HPhi(allocator, phi->GetRegNumber(), inputs.size(), type); |
| // Copy the inputs. Note that the graph may not be correctly typed |
| // by doing this copy, but the type propagation phase will fix it. |
| ArrayRef<HUserRecord<HInstruction*>> new_input_records = new_phi->GetInputRecords(); |
| for (size_t i = 0; i < inputs.size(); ++i) { |
| new_input_records[i] = HUserRecord<HInstruction*>(inputs[i]); |
| } |
| phi->GetBlock()->InsertPhiAfter(new_phi, phi); |
| DCHECK(new_phi->IsLive()); |
| return new_phi; |
| } else { |
| // An existing equivalent was found. If it is dead, conflict was previously |
| // identified and we return nullptr instead. |
| HPhi* next_phi = next->AsPhi(); |
| DCHECK_EQ(next_phi->GetType(), type); |
| return next_phi->IsLive() ? next_phi : nullptr; |
| } |
| } |
| |
| HArrayGet* SsaBuilder::GetFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) { |
| DCHECK(DataType::IsIntegralType(aget->GetType())); |
| |
| if (!DataType::IsIntOrLongType(aget->GetType())) { |
| // Cannot type boolean, char, byte, short to float/double. |
| return nullptr; |
| } |
| |
| DCHECK(ContainsElement(ambiguous_agets_, aget)); |
| if (agets_fixed_) { |
| // This used to be an ambiguous ArrayGet but its type has been resolved to |
| // int/long. Requesting a float/double equivalent should lead to a conflict. |
| if (kIsDebugBuild) { |
| ScopedObjectAccess soa(Thread::Current()); |
| DCHECK(DataType::IsIntOrLongType(GetPrimitiveArrayComponentType(aget->GetArray()))); |
| } |
| return nullptr; |
| } else { |
| // This is an ambiguous ArrayGet which has not been resolved yet. Return an |
| // equivalent float/double instruction to use until it is resolved. |
| HArrayGet* equivalent = FindFloatOrDoubleEquivalentOfArrayGet(aget); |
| return (equivalent == nullptr) ? CreateFloatOrDoubleEquivalentOfArrayGet(aget) : equivalent; |
| } |
| } |
| |
| HInstruction* SsaBuilder::GetFloatOrDoubleEquivalent(HInstruction* value, DataType::Type type) { |
| if (value->IsArrayGet()) { |
| return GetFloatOrDoubleEquivalentOfArrayGet(value->AsArrayGet()); |
| } else if (value->IsLongConstant()) { |
| return GetDoubleEquivalent(value->AsLongConstant()); |
| } else if (value->IsIntConstant()) { |
| return GetFloatEquivalent(value->AsIntConstant()); |
| } else if (value->IsPhi()) { |
| return GetFloatDoubleOrReferenceEquivalentOfPhi(value->AsPhi(), type); |
| } else { |
| return nullptr; |
| } |
| } |
| |
| HInstruction* SsaBuilder::GetReferenceTypeEquivalent(HInstruction* value) { |
| if (value->IsIntConstant() && value->AsIntConstant()->GetValue() == 0) { |
| return graph_->GetNullConstant(); |
| } else if (value->IsPhi()) { |
| return GetFloatDoubleOrReferenceEquivalentOfPhi(value->AsPhi(), DataType::Type::kReference); |
| } else { |
| return nullptr; |
| } |
| } |
| |
| } // namespace art |