| /* |
| * Copyright (C) 2015 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 "reference_type_propagation.h" |
| |
| #include "class_linker-inl.h" |
| #include "mirror/class-inl.h" |
| #include "mirror/dex_cache.h" |
| #include "scoped_thread_state_change.h" |
| |
| namespace art { |
| |
| class RTPVisitor : public HGraphDelegateVisitor { |
| public: |
| RTPVisitor(HGraph* graph, |
| StackHandleScopeCollection* handles, |
| GrowableArray<HInstruction*>* worklist, |
| ReferenceTypeInfo::TypeHandle object_class_handle, |
| ReferenceTypeInfo::TypeHandle class_class_handle, |
| ReferenceTypeInfo::TypeHandle string_class_handle, |
| ReferenceTypeInfo::TypeHandle throwable_class_handle) |
| : HGraphDelegateVisitor(graph), |
| handles_(handles), |
| object_class_handle_(object_class_handle), |
| class_class_handle_(class_class_handle), |
| string_class_handle_(string_class_handle), |
| throwable_class_handle_(throwable_class_handle), |
| worklist_(worklist) {} |
| |
| void VisitNullConstant(HNullConstant* null_constant) OVERRIDE; |
| void VisitNewInstance(HNewInstance* new_instance) OVERRIDE; |
| void VisitLoadClass(HLoadClass* load_class) OVERRIDE; |
| void VisitClinitCheck(HClinitCheck* clinit_check) OVERRIDE; |
| void VisitLoadString(HLoadString* instr) OVERRIDE; |
| void VisitLoadException(HLoadException* instr) OVERRIDE; |
| void VisitNewArray(HNewArray* instr) OVERRIDE; |
| void VisitParameterValue(HParameterValue* instr) OVERRIDE; |
| void UpdateFieldAccessTypeInfo(HInstruction* instr, const FieldInfo& info); |
| void SetClassAsTypeInfo(HInstruction* instr, mirror::Class* klass, bool is_exact); |
| void VisitInstanceFieldGet(HInstanceFieldGet* instr) OVERRIDE; |
| void VisitStaticFieldGet(HStaticFieldGet* instr) OVERRIDE; |
| void VisitInvoke(HInvoke* instr) OVERRIDE; |
| void VisitArrayGet(HArrayGet* instr) OVERRIDE; |
| void VisitCheckCast(HCheckCast* instr) OVERRIDE; |
| void VisitNullCheck(HNullCheck* instr) OVERRIDE; |
| void VisitFakeString(HFakeString* instr) OVERRIDE; |
| void UpdateReferenceTypeInfo(HInstruction* instr, |
| uint16_t type_idx, |
| const DexFile& dex_file, |
| bool is_exact); |
| |
| private: |
| StackHandleScopeCollection* handles_; |
| ReferenceTypeInfo::TypeHandle object_class_handle_; |
| ReferenceTypeInfo::TypeHandle class_class_handle_; |
| ReferenceTypeInfo::TypeHandle string_class_handle_; |
| ReferenceTypeInfo::TypeHandle throwable_class_handle_; |
| GrowableArray<HInstruction*>* worklist_; |
| |
| static constexpr size_t kDefaultWorklistSize = 8; |
| }; |
| |
| ReferenceTypePropagation::ReferenceTypePropagation(HGraph* graph, |
| StackHandleScopeCollection* handles, |
| const char* name) |
| : HOptimization(graph, name), |
| handles_(handles), |
| worklist_(graph->GetArena(), kDefaultWorklistSize) { |
| // Mutator lock is required for NewHandle, but annotalysis ignores constructors. |
| ScopedObjectAccess soa(Thread::Current()); |
| ClassLinker* linker = Runtime::Current()->GetClassLinker(); |
| object_class_handle_ = handles_->NewHandle(linker->GetClassRoot(ClassLinker::kJavaLangObject)); |
| string_class_handle_ = handles_->NewHandle(linker->GetClassRoot(ClassLinker::kJavaLangString)); |
| class_class_handle_ = handles_->NewHandle(linker->GetClassRoot(ClassLinker::kJavaLangClass)); |
| throwable_class_handle_ = |
| handles_->NewHandle(linker->GetClassRoot(ClassLinker::kJavaLangThrowable)); |
| |
| if (kIsDebugBuild) { |
| DCHECK(ReferenceTypeInfo::IsValidHandle(object_class_handle_)); |
| DCHECK(ReferenceTypeInfo::IsValidHandle(class_class_handle_)); |
| DCHECK(ReferenceTypeInfo::IsValidHandle(string_class_handle_)); |
| DCHECK(ReferenceTypeInfo::IsValidHandle(throwable_class_handle_)); |
| } |
| } |
| |
| void ReferenceTypePropagation::Run() { |
| // To properly propagate type info we need to visit in the dominator-based order. |
| // Reverse post order guarantees a node's dominators are visited first. |
| // We take advantage of this order in `VisitBasicBlock`. |
| for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) { |
| VisitBasicBlock(it.Current()); |
| } |
| ProcessWorklist(); |
| |
| if (kIsDebugBuild) { |
| // TODO: move this to the graph checker. |
| ScopedObjectAccess soa(Thread::Current()); |
| for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) { |
| HBasicBlock* block = it.Current(); |
| for (HInstructionIterator iti(block->GetInstructions()); !iti.Done(); iti.Advance()) { |
| HInstruction* instr = iti.Current(); |
| if (instr->GetType() == Primitive::kPrimNot) { |
| DCHECK(instr->GetReferenceTypeInfo().IsValid()) |
| << "Invalid RTI for instruction: " << instr->DebugName(); |
| if (instr->IsBoundType()) { |
| DCHECK(instr->AsBoundType()->GetUpperBound().IsValid()); |
| } else if (instr->IsLoadClass()) { |
| DCHECK(instr->AsLoadClass()->GetReferenceTypeInfo().IsExact()); |
| DCHECK(instr->AsLoadClass()->GetLoadedClassRTI().IsValid()); |
| } else if (instr->IsNullCheck()) { |
| DCHECK(instr->GetReferenceTypeInfo().IsEqual(instr->InputAt(0)->GetReferenceTypeInfo())) |
| << "NullCheck " << instr->GetReferenceTypeInfo() |
| << "Input(0) " << instr->InputAt(0)->GetReferenceTypeInfo(); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| void ReferenceTypePropagation::VisitBasicBlock(HBasicBlock* block) { |
| RTPVisitor visitor(graph_, |
| handles_, |
| &worklist_, |
| object_class_handle_, |
| class_class_handle_, |
| string_class_handle_, |
| throwable_class_handle_); |
| // Handle Phis first as there might be instructions in the same block who depend on them. |
| for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) { |
| VisitPhi(it.Current()->AsPhi()); |
| } |
| |
| // Handle instructions. |
| for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) { |
| HInstruction* instr = it.Current(); |
| instr->Accept(&visitor); |
| } |
| |
| // Add extra nodes to bound types. |
| BoundTypeForIfNotNull(block); |
| BoundTypeForIfInstanceOf(block); |
| } |
| |
| // Create a bound type for the given object narrowing the type as much as possible. |
| // The BoundType upper values for the super type and can_be_null will be taken from |
| // load_class.GetLoadedClassRTI() and upper_can_be_null. |
| static HBoundType* CreateBoundType(ArenaAllocator* arena, |
| HInstruction* obj, |
| HLoadClass* load_class, |
| bool upper_can_be_null) |
| SHARED_REQUIRES(Locks::mutator_lock_) { |
| ReferenceTypeInfo obj_rti = obj->GetReferenceTypeInfo(); |
| ReferenceTypeInfo class_rti = load_class->GetLoadedClassRTI(); |
| HBoundType* bound_type = new (arena) HBoundType(obj, class_rti, upper_can_be_null); |
| // Narrow the type as much as possible. |
| if (class_rti.GetTypeHandle()->IsFinal()) { |
| bound_type->SetReferenceTypeInfo( |
| ReferenceTypeInfo::Create(class_rti.GetTypeHandle(), /* is_exact */ true)); |
| } else if (obj_rti.IsValid() && class_rti.IsSupertypeOf(obj_rti)) { |
| bound_type->SetReferenceTypeInfo(obj_rti); |
| } else { |
| bound_type->SetReferenceTypeInfo( |
| ReferenceTypeInfo::Create(class_rti.GetTypeHandle(), /* is_exact */ false)); |
| } |
| if (upper_can_be_null) { |
| bound_type->SetCanBeNull(obj->CanBeNull()); |
| } |
| return bound_type; |
| } |
| |
| // Check if we should create a bound type for the given object at the specified |
| // position. Because of inlining and the fact we run RTP more than once and we |
| // might have a HBoundType already. If we do, we should not create a new one. |
| // In this case we also assert that there are no other uses of the object (except |
| // the bound type) dominated by the specified dominator_instr or dominator_block. |
| static bool ShouldCreateBoundType(HInstruction* position, |
| HInstruction* obj, |
| ReferenceTypeInfo upper_bound, |
| HInstruction* dominator_instr, |
| HBasicBlock* dominator_block) |
| SHARED_REQUIRES(Locks::mutator_lock_) { |
| // If the position where we should insert the bound type is not already a |
| // a bound type then we need to create one. |
| if (position == nullptr || !position->IsBoundType()) { |
| return true; |
| } |
| |
| HBoundType* existing_bound_type = position->AsBoundType(); |
| if (existing_bound_type->GetUpperBound().IsSupertypeOf(upper_bound)) { |
| if (kIsDebugBuild) { |
| // Check that the existing HBoundType dominates all the uses. |
| for (HUseIterator<HInstruction*> it(obj->GetUses()); !it.Done(); it.Advance()) { |
| HInstruction* user = it.Current()->GetUser(); |
| if (dominator_instr != nullptr) { |
| DCHECK(!dominator_instr->StrictlyDominates(user) |
| || user == existing_bound_type |
| || existing_bound_type->StrictlyDominates(user)); |
| } else if (dominator_block != nullptr) { |
| DCHECK(!dominator_block->Dominates(user->GetBlock()) |
| || user == existing_bound_type |
| || existing_bound_type->StrictlyDominates(user)); |
| } |
| } |
| } |
| } else { |
| // TODO: if the current bound type is a refinement we could update the |
| // existing_bound_type with the a new upper limit. However, we also need to |
| // update its users and have access to the work list. |
| } |
| return false; |
| } |
| |
| void ReferenceTypePropagation::BoundTypeForIfNotNull(HBasicBlock* block) { |
| HIf* ifInstruction = block->GetLastInstruction()->AsIf(); |
| if (ifInstruction == nullptr) { |
| return; |
| } |
| HInstruction* ifInput = ifInstruction->InputAt(0); |
| if (!ifInput->IsNotEqual() && !ifInput->IsEqual()) { |
| return; |
| } |
| HInstruction* input0 = ifInput->InputAt(0); |
| HInstruction* input1 = ifInput->InputAt(1); |
| HInstruction* obj = nullptr; |
| |
| if (input1->IsNullConstant()) { |
| obj = input0; |
| } else if (input0->IsNullConstant()) { |
| obj = input1; |
| } else { |
| return; |
| } |
| |
| if (!obj->CanBeNull() || obj->IsNullConstant()) { |
| // Null check is dead code and will be removed by DCE. |
| return; |
| } |
| DCHECK(!obj->IsLoadClass()) << "We should not replace HLoadClass instructions"; |
| |
| // We only need to bound the type if we have uses in the relevant block. |
| // So start with null and create the HBoundType lazily, only if it's needed. |
| HBoundType* bound_type = nullptr; |
| HBasicBlock* notNullBlock = ifInput->IsNotEqual() |
| ? ifInstruction->IfTrueSuccessor() |
| : ifInstruction->IfFalseSuccessor(); |
| |
| for (HUseIterator<HInstruction*> it(obj->GetUses()); !it.Done(); it.Advance()) { |
| HInstruction* user = it.Current()->GetUser(); |
| if (notNullBlock->Dominates(user->GetBlock())) { |
| if (bound_type == nullptr) { |
| ScopedObjectAccess soa(Thread::Current()); |
| HInstruction* insert_point = notNullBlock->GetFirstInstruction(); |
| ReferenceTypeInfo object_rti = ReferenceTypeInfo::Create( |
| object_class_handle_, /* is_exact */ true); |
| if (ShouldCreateBoundType(insert_point, obj, object_rti, nullptr, notNullBlock)) { |
| bound_type = new (graph_->GetArena()) HBoundType( |
| obj, object_rti, /* bound_can_be_null */ false); |
| if (obj->GetReferenceTypeInfo().IsValid()) { |
| bound_type->SetReferenceTypeInfo(obj->GetReferenceTypeInfo()); |
| } |
| notNullBlock->InsertInstructionBefore(bound_type, insert_point); |
| } else { |
| // We already have a bound type on the position we would need to insert |
| // the new one. The existing bound type should dominate all the users |
| // (dchecked) so there's no need to continue. |
| break; |
| } |
| } |
| user->ReplaceInput(bound_type, it.Current()->GetIndex()); |
| } |
| } |
| } |
| |
| // Detects if `block` is the True block for the pattern |
| // `if (x instanceof ClassX) { }` |
| // If that's the case insert an HBoundType instruction to bound the type of `x` |
| // to `ClassX` in the scope of the dominated blocks. |
| void ReferenceTypePropagation::BoundTypeForIfInstanceOf(HBasicBlock* block) { |
| HIf* ifInstruction = block->GetLastInstruction()->AsIf(); |
| if (ifInstruction == nullptr) { |
| return; |
| } |
| HInstruction* ifInput = ifInstruction->InputAt(0); |
| HInstruction* instanceOf = nullptr; |
| HBasicBlock* instanceOfTrueBlock = nullptr; |
| |
| // The instruction simplifier has transformed: |
| // - `if (a instanceof A)` into an HIf with an HInstanceOf input |
| // - `if (!(a instanceof A)` into an HIf with an HBooleanNot input (which in turn |
| // has an HInstanceOf input) |
| // So we should not see the usual HEqual here. |
| if (ifInput->IsInstanceOf()) { |
| instanceOf = ifInput; |
| instanceOfTrueBlock = ifInstruction->IfTrueSuccessor(); |
| } else if (ifInput->IsBooleanNot() && ifInput->InputAt(0)->IsInstanceOf()) { |
| instanceOf = ifInput->InputAt(0); |
| instanceOfTrueBlock = ifInstruction->IfFalseSuccessor(); |
| } else { |
| return; |
| } |
| |
| // We only need to bound the type if we have uses in the relevant block. |
| // So start with null and create the HBoundType lazily, only if it's needed. |
| HBoundType* bound_type = nullptr; |
| |
| HInstruction* obj = instanceOf->InputAt(0); |
| if (obj->GetReferenceTypeInfo().IsExact() && !obj->IsPhi()) { |
| // This method is being called while doing a fixed-point calculation |
| // over phis. Non-phis instruction whose type is already known do |
| // not need to be bound to another type. |
| // Not that this also prevents replacing `HLoadClass` with a `HBoundType`. |
| // `HCheckCast` and `HInstanceOf` expect a `HLoadClass` as a second |
| // input. |
| return; |
| } |
| DCHECK(!obj->IsLoadClass()) << "We should not replace HLoadClass instructions"; |
| for (HUseIterator<HInstruction*> it(obj->GetUses()); !it.Done(); it.Advance()) { |
| HInstruction* user = it.Current()->GetUser(); |
| if (instanceOfTrueBlock->Dominates(user->GetBlock())) { |
| if (bound_type == nullptr) { |
| ScopedObjectAccess soa(Thread::Current()); |
| HLoadClass* load_class = instanceOf->InputAt(1)->AsLoadClass(); |
| ReferenceTypeInfo class_rti = load_class->GetLoadedClassRTI(); |
| HInstruction* insert_point = instanceOfTrueBlock->GetFirstInstruction(); |
| if (ShouldCreateBoundType(insert_point, obj, class_rti, nullptr, instanceOfTrueBlock)) { |
| bound_type = CreateBoundType( |
| graph_->GetArena(), |
| obj, |
| load_class, |
| false /* InstanceOf ensures the object is not null. */); |
| instanceOfTrueBlock->InsertInstructionBefore(bound_type, insert_point); |
| } else { |
| // We already have a bound type on the position we would need to insert |
| // the new one. The existing bound type should dominate all the users |
| // (dchecked) so there's no need to continue. |
| break; |
| } |
| } |
| user->ReplaceInput(bound_type, it.Current()->GetIndex()); |
| } |
| } |
| } |
| |
| void RTPVisitor::SetClassAsTypeInfo(HInstruction* instr, |
| mirror::Class* klass, |
| bool is_exact) { |
| if (instr->IsInvokeStaticOrDirect() && instr->AsInvokeStaticOrDirect()->IsStringInit()) { |
| // Calls to String.<init> are replaced with a StringFactory. |
| if (kIsDebugBuild) { |
| ScopedObjectAccess soa(Thread::Current()); |
| ClassLinker* cl = Runtime::Current()->GetClassLinker(); |
| mirror::DexCache* dex_cache = cl->FindDexCache( |
| soa.Self(), instr->AsInvoke()->GetDexFile(), false); |
| ArtMethod* method = dex_cache->GetResolvedMethod( |
| instr->AsInvoke()->GetDexMethodIndex(), cl->GetImagePointerSize()); |
| DCHECK(method != nullptr); |
| mirror::Class* declaring_class = method->GetDeclaringClass(); |
| DCHECK(declaring_class != nullptr); |
| DCHECK(declaring_class->IsStringClass()) |
| << "Expected String class: " << PrettyDescriptor(declaring_class); |
| DCHECK(method->IsConstructor()) |
| << "Expected String.<init>: " << PrettyMethod(method); |
| } |
| instr->SetReferenceTypeInfo( |
| ReferenceTypeInfo::Create(string_class_handle_, /* is_exact */ true)); |
| } else if (klass != nullptr) { |
| ScopedObjectAccess soa(Thread::Current()); |
| ReferenceTypeInfo::TypeHandle handle = handles_->NewHandle(klass); |
| is_exact = is_exact || klass->IsFinal(); |
| instr->SetReferenceTypeInfo(ReferenceTypeInfo::Create(handle, is_exact)); |
| } else { |
| instr->SetReferenceTypeInfo( |
| ReferenceTypeInfo::Create(object_class_handle_, /* is_exact */ false)); |
| } |
| } |
| |
| void RTPVisitor::UpdateReferenceTypeInfo(HInstruction* instr, |
| uint16_t type_idx, |
| const DexFile& dex_file, |
| bool is_exact) { |
| DCHECK_EQ(instr->GetType(), Primitive::kPrimNot); |
| |
| ScopedObjectAccess soa(Thread::Current()); |
| mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache( |
| soa.Self(), dex_file, false); |
| // Get type from dex cache assuming it was populated by the verifier. |
| SetClassAsTypeInfo(instr, dex_cache->GetResolvedType(type_idx), is_exact); |
| } |
| |
| void RTPVisitor::VisitNullConstant(HNullConstant* instr) { |
| // TODO: The null constant could be bound contextually (e.g. based on return statements) |
| // to a more precise type. |
| instr->SetReferenceTypeInfo( |
| ReferenceTypeInfo::Create(object_class_handle_, /* is_exact */ false)); |
| } |
| |
| void RTPVisitor::VisitNewInstance(HNewInstance* instr) { |
| UpdateReferenceTypeInfo(instr, instr->GetTypeIndex(), instr->GetDexFile(), /* is_exact */ true); |
| } |
| |
| void RTPVisitor::VisitNewArray(HNewArray* instr) { |
| UpdateReferenceTypeInfo(instr, instr->GetTypeIndex(), instr->GetDexFile(), /* is_exact */ true); |
| } |
| |
| void RTPVisitor::VisitParameterValue(HParameterValue* instr) { |
| ScopedObjectAccess soa(Thread::Current()); |
| // We check if the existing type is valid: the inliner may have set it. |
| if (instr->GetType() == Primitive::kPrimNot && !instr->GetReferenceTypeInfo().IsValid()) { |
| // TODO: parse the signature and add precise types for the parameters. |
| SetClassAsTypeInfo(instr, nullptr, /* is_exact */ false); |
| } |
| } |
| |
| void RTPVisitor::UpdateFieldAccessTypeInfo(HInstruction* instr, |
| const FieldInfo& info) { |
| // The field index is unknown only during tests. |
| if (instr->GetType() != Primitive::kPrimNot || info.GetFieldIndex() == kUnknownFieldIndex) { |
| return; |
| } |
| |
| ScopedObjectAccess soa(Thread::Current()); |
| ClassLinker* cl = Runtime::Current()->GetClassLinker(); |
| mirror::DexCache* dex_cache = cl->FindDexCache(soa.Self(), info.GetDexFile(), false); |
| ArtField* field = cl->GetResolvedField(info.GetFieldIndex(), dex_cache); |
| // TODO: There are certain cases where we can't resolve the field. |
| // b/21914925 is open to keep track of a repro case for this issue. |
| mirror::Class* klass = (field == nullptr) ? nullptr : field->GetType<false>(); |
| SetClassAsTypeInfo(instr, klass, /* is_exact */ false); |
| } |
| |
| void RTPVisitor::VisitInstanceFieldGet(HInstanceFieldGet* instr) { |
| UpdateFieldAccessTypeInfo(instr, instr->GetFieldInfo()); |
| } |
| |
| void RTPVisitor::VisitStaticFieldGet(HStaticFieldGet* instr) { |
| UpdateFieldAccessTypeInfo(instr, instr->GetFieldInfo()); |
| } |
| |
| void RTPVisitor::VisitLoadClass(HLoadClass* instr) { |
| ScopedObjectAccess soa(Thread::Current()); |
| mirror::DexCache* dex_cache = |
| Runtime::Current()->GetClassLinker()->FindDexCache(soa.Self(), instr->GetDexFile(), false); |
| // Get type from dex cache assuming it was populated by the verifier. |
| mirror::Class* resolved_class = dex_cache->GetResolvedType(instr->GetTypeIndex()); |
| // TODO: investigating why we are still getting unresolved classes: b/22821472. |
| ReferenceTypeInfo::TypeHandle handle = (resolved_class != nullptr) |
| ? handles_->NewHandle(resolved_class) |
| : object_class_handle_; |
| instr->SetLoadedClassRTI(ReferenceTypeInfo::Create(handle, /* is_exact */ true)); |
| instr->SetReferenceTypeInfo(ReferenceTypeInfo::Create(class_class_handle_, /* is_exact */ true)); |
| } |
| |
| void RTPVisitor::VisitClinitCheck(HClinitCheck* instr) { |
| instr->SetReferenceTypeInfo(instr->InputAt(0)->GetReferenceTypeInfo()); |
| } |
| |
| void RTPVisitor::VisitLoadString(HLoadString* instr) { |
| instr->SetReferenceTypeInfo(ReferenceTypeInfo::Create(string_class_handle_, /* is_exact */ true)); |
| } |
| |
| void RTPVisitor::VisitLoadException(HLoadException* instr) { |
| DCHECK(instr->GetBlock()->IsCatchBlock()); |
| TryCatchInformation* catch_info = instr->GetBlock()->GetTryCatchInformation(); |
| |
| if (catch_info->IsCatchAllTypeIndex()) { |
| instr->SetReferenceTypeInfo(ReferenceTypeInfo::Create(throwable_class_handle_, |
| /* is_exact */ false)); |
| } else { |
| UpdateReferenceTypeInfo(instr, |
| catch_info->GetCatchTypeIndex(), |
| catch_info->GetCatchDexFile(), |
| /* is_exact */ false); |
| } |
| } |
| |
| void RTPVisitor::VisitNullCheck(HNullCheck* instr) { |
| ScopedObjectAccess soa(Thread::Current()); |
| ReferenceTypeInfo parent_rti = instr->InputAt(0)->GetReferenceTypeInfo(); |
| DCHECK(parent_rti.IsValid()); |
| instr->SetReferenceTypeInfo(parent_rti); |
| } |
| |
| void RTPVisitor::VisitFakeString(HFakeString* instr) { |
| instr->SetReferenceTypeInfo(ReferenceTypeInfo::Create(string_class_handle_, /* is_exact */ true)); |
| } |
| |
| void RTPVisitor::VisitCheckCast(HCheckCast* check_cast) { |
| HInstruction* obj = check_cast->InputAt(0); |
| HBoundType* bound_type = nullptr; |
| for (HUseIterator<HInstruction*> it(obj->GetUses()); !it.Done(); it.Advance()) { |
| HInstruction* user = it.Current()->GetUser(); |
| if (check_cast->StrictlyDominates(user)) { |
| if (bound_type == nullptr) { |
| ScopedObjectAccess soa(Thread::Current()); |
| HLoadClass* load_class = check_cast->InputAt(1)->AsLoadClass(); |
| ReferenceTypeInfo class_rti = load_class->GetLoadedClassRTI(); |
| if (ShouldCreateBoundType(check_cast->GetNext(), obj, class_rti, check_cast, nullptr)) { |
| bound_type = CreateBoundType( |
| GetGraph()->GetArena(), |
| obj, |
| load_class, |
| true /* CheckCast succeeds for nulls. */); |
| check_cast->GetBlock()->InsertInstructionAfter(bound_type, check_cast); |
| } else { |
| // Update nullability of the existing bound type, which may not have known |
| // that its input was not null when it was being created. |
| bound_type = check_cast->GetNext()->AsBoundType(); |
| bound_type->SetCanBeNull(obj->CanBeNull()); |
| // We already have a bound type on the position we would need to insert |
| // the new one. The existing bound type should dominate all the users |
| // (dchecked) so there's no need to continue. |
| break; |
| } |
| } |
| user->ReplaceInput(bound_type, it.Current()->GetIndex()); |
| } |
| } |
| } |
| |
| void ReferenceTypePropagation::VisitPhi(HPhi* phi) { |
| if (phi->GetType() != Primitive::kPrimNot) { |
| return; |
| } |
| |
| if (phi->GetBlock()->IsLoopHeader()) { |
| // Set the initial type for the phi. Use the non back edge input for reaching |
| // a fixed point faster. |
| AddToWorklist(phi); |
| phi->SetCanBeNull(phi->InputAt(0)->CanBeNull()); |
| phi->SetReferenceTypeInfo(phi->InputAt(0)->GetReferenceTypeInfo()); |
| } else { |
| // 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. |
| UpdateNullability(phi); |
| UpdateReferenceTypeInfo(phi); |
| } |
| } |
| |
| ReferenceTypeInfo ReferenceTypePropagation::MergeTypes(const ReferenceTypeInfo& a, |
| const ReferenceTypeInfo& b) { |
| if (!b.IsValid()) { |
| return a; |
| } |
| if (!a.IsValid()) { |
| return b; |
| } |
| |
| bool is_exact = a.IsExact() && b.IsExact(); |
| Handle<mirror::Class> type_handle; |
| |
| if (a.GetTypeHandle().Get() == b.GetTypeHandle().Get()) { |
| type_handle = a.GetTypeHandle(); |
| } else if (a.IsSupertypeOf(b)) { |
| type_handle = a.GetTypeHandle(); |
| is_exact = false; |
| } else if (b.IsSupertypeOf(a)) { |
| type_handle = b.GetTypeHandle(); |
| is_exact = false; |
| } else { |
| // TODO: Find the first common super class. |
| type_handle = object_class_handle_; |
| is_exact = false; |
| } |
| |
| return ReferenceTypeInfo::Create(type_handle, is_exact); |
| } |
| |
| static void UpdateArrayGet(HArrayGet* instr, |
| StackHandleScopeCollection* handles, |
| ReferenceTypeInfo::TypeHandle object_class_handle) |
| SHARED_REQUIRES(Locks::mutator_lock_) { |
| DCHECK_EQ(Primitive::kPrimNot, instr->GetType()); |
| |
| ReferenceTypeInfo parent_rti = instr->InputAt(0)->GetReferenceTypeInfo(); |
| DCHECK(parent_rti.IsValid()); |
| |
| Handle<mirror::Class> handle = parent_rti.GetTypeHandle(); |
| if (handle->IsObjectArrayClass()) { |
| ReferenceTypeInfo::TypeHandle component_handle = handles->NewHandle(handle->GetComponentType()); |
| instr->SetReferenceTypeInfo( |
| ReferenceTypeInfo::Create(component_handle, /* is_exact */ false)); |
| } else { |
| // We don't know what the parent actually is, so we fallback to object. |
| instr->SetReferenceTypeInfo( |
| ReferenceTypeInfo::Create(object_class_handle, /* is_exact */ false)); |
| } |
| |
| return; |
| } |
| |
| bool ReferenceTypePropagation::UpdateReferenceTypeInfo(HInstruction* instr) { |
| ScopedObjectAccess soa(Thread::Current()); |
| |
| ReferenceTypeInfo previous_rti = instr->GetReferenceTypeInfo(); |
| if (instr->IsBoundType()) { |
| UpdateBoundType(instr->AsBoundType()); |
| } else if (instr->IsPhi()) { |
| UpdatePhi(instr->AsPhi()); |
| } else if (instr->IsNullCheck()) { |
| ReferenceTypeInfo parent_rti = instr->InputAt(0)->GetReferenceTypeInfo(); |
| if (parent_rti.IsValid()) { |
| instr->SetReferenceTypeInfo(parent_rti); |
| } |
| } else if (instr->IsArrayGet()) { |
| // TODO: consider if it's worth "looking back" and bounding the input object |
| // to an array type. |
| UpdateArrayGet(instr->AsArrayGet(), handles_, object_class_handle_); |
| } else { |
| LOG(FATAL) << "Invalid instruction (should not get here)"; |
| } |
| |
| return !previous_rti.IsEqual(instr->GetReferenceTypeInfo()); |
| } |
| |
| void RTPVisitor::VisitInvoke(HInvoke* instr) { |
| if (instr->GetType() != Primitive::kPrimNot) { |
| return; |
| } |
| |
| ScopedObjectAccess soa(Thread::Current()); |
| ClassLinker* cl = Runtime::Current()->GetClassLinker(); |
| mirror::DexCache* dex_cache = cl->FindDexCache(soa.Self(), instr->GetDexFile()); |
| ArtMethod* method = dex_cache->GetResolvedMethod( |
| instr->GetDexMethodIndex(), cl->GetImagePointerSize()); |
| mirror::Class* klass = (method == nullptr) ? nullptr : method->GetReturnType(false); |
| SetClassAsTypeInfo(instr, klass, /* is_exact */ false); |
| } |
| |
| void RTPVisitor::VisitArrayGet(HArrayGet* instr) { |
| if (instr->GetType() != Primitive::kPrimNot) { |
| return; |
| } |
| ScopedObjectAccess soa(Thread::Current()); |
| UpdateArrayGet(instr, handles_, object_class_handle_); |
| if (!instr->GetReferenceTypeInfo().IsValid()) { |
| worklist_->Add(instr); |
| } |
| } |
| |
| void ReferenceTypePropagation::UpdateBoundType(HBoundType* instr) { |
| ReferenceTypeInfo new_rti = instr->InputAt(0)->GetReferenceTypeInfo(); |
| if (!new_rti.IsValid()) { |
| return; // No new info yet. |
| } |
| |
| // Make sure that we don't go over the bounded type. |
| ReferenceTypeInfo upper_bound_rti = instr->GetUpperBound(); |
| if (!upper_bound_rti.IsSupertypeOf(new_rti)) { |
| new_rti = upper_bound_rti; |
| } |
| instr->SetReferenceTypeInfo(new_rti); |
| } |
| |
| void ReferenceTypePropagation::UpdatePhi(HPhi* instr) { |
| ReferenceTypeInfo new_rti = instr->InputAt(0)->GetReferenceTypeInfo(); |
| if (new_rti.IsValid() && new_rti.IsObjectClass() && !new_rti.IsExact()) { |
| // Early return if we are Object and inexact. |
| instr->SetReferenceTypeInfo(new_rti); |
| return; |
| } |
| for (size_t i = 1; i < instr->InputCount(); i++) { |
| new_rti = MergeTypes(new_rti, instr->InputAt(i)->GetReferenceTypeInfo()); |
| if (new_rti.IsValid() && new_rti.IsObjectClass()) { |
| if (!new_rti.IsExact()) { |
| break; |
| } else { |
| continue; |
| } |
| } |
| } |
| instr->SetReferenceTypeInfo(new_rti); |
| } |
| |
| // Re-computes and updates the nullability of the instruction. Returns whether or |
| // not the nullability was changed. |
| bool ReferenceTypePropagation::UpdateNullability(HInstruction* instr) { |
| DCHECK(instr->IsPhi() |
| || instr->IsBoundType() |
| || instr->IsNullCheck() |
| || instr->IsArrayGet()); |
| |
| if (!instr->IsPhi() && !instr->IsBoundType()) { |
| return false; |
| } |
| |
| bool existing_can_be_null = instr->CanBeNull(); |
| if (instr->IsPhi()) { |
| HPhi* phi = instr->AsPhi(); |
| bool new_can_be_null = false; |
| for (size_t i = 0; i < phi->InputCount(); i++) { |
| if (phi->InputAt(i)->CanBeNull()) { |
| new_can_be_null = true; |
| break; |
| } |
| } |
| phi->SetCanBeNull(new_can_be_null); |
| } else if (instr->IsBoundType()) { |
| HBoundType* bound_type = instr->AsBoundType(); |
| bound_type->SetCanBeNull(instr->InputAt(0)->CanBeNull() && bound_type->GetUpperCanBeNull()); |
| } |
| return existing_can_be_null != instr->CanBeNull(); |
| } |
| |
| void ReferenceTypePropagation::ProcessWorklist() { |
| while (!worklist_.IsEmpty()) { |
| HInstruction* instruction = worklist_.Pop(); |
| if (UpdateNullability(instruction) || UpdateReferenceTypeInfo(instruction)) { |
| AddDependentInstructionsToWorklist(instruction); |
| } |
| } |
| } |
| |
| void ReferenceTypePropagation::AddToWorklist(HInstruction* instruction) { |
| DCHECK_EQ(instruction->GetType(), Primitive::kPrimNot) |
| << instruction->DebugName() << ":" << instruction->GetType(); |
| worklist_.Add(instruction); |
| } |
| |
| void ReferenceTypePropagation::AddDependentInstructionsToWorklist(HInstruction* instruction) { |
| for (HUseIterator<HInstruction*> it(instruction->GetUses()); !it.Done(); it.Advance()) { |
| HInstruction* user = it.Current()->GetUser(); |
| if (user->IsPhi() |
| || user->IsBoundType() |
| || user->IsNullCheck() |
| || (user->IsArrayGet() && (user->GetType() == Primitive::kPrimNot))) { |
| AddToWorklist(user); |
| } |
| } |
| } |
| } // namespace art |
