| /* |
| * Copyright (C) 2016 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 "cha.h" |
| |
| #include "art_method-inl.h" |
| #include "jit/jit.h" |
| #include "jit/jit_code_cache.h" |
| #include "runtime.h" |
| #include "scoped_thread_state_change-inl.h" |
| #include "stack.h" |
| #include "thread.h" |
| #include "thread_list.h" |
| #include "thread_pool.h" |
| |
| namespace art { |
| |
| void ClassHierarchyAnalysis::AddDependency(ArtMethod* method, |
| ArtMethod* dependent_method, |
| OatQuickMethodHeader* dependent_header) { |
| const auto it = cha_dependency_map_.insert( |
| decltype(cha_dependency_map_)::value_type(method, ListOfDependentPairs())).first; |
| it->second.push_back({dependent_method, dependent_header}); |
| } |
| |
| static const ClassHierarchyAnalysis::ListOfDependentPairs s_empty_vector; |
| |
| const ClassHierarchyAnalysis::ListOfDependentPairs& ClassHierarchyAnalysis::GetDependents( |
| ArtMethod* method) { |
| auto it = cha_dependency_map_.find(method); |
| if (it != cha_dependency_map_.end()) { |
| return it->second; |
| } |
| return s_empty_vector; |
| } |
| |
| void ClassHierarchyAnalysis::RemoveAllDependenciesFor(ArtMethod* method) { |
| cha_dependency_map_.erase(method); |
| } |
| |
| void ClassHierarchyAnalysis::RemoveDependentsWithMethodHeaders( |
| const std::unordered_set<OatQuickMethodHeader*>& method_headers) { |
| // Iterate through all entries in the dependency map and remove any entry that |
| // contains one of those in method_headers. |
| for (auto map_it = cha_dependency_map_.begin(); map_it != cha_dependency_map_.end(); ) { |
| ListOfDependentPairs& dependents = map_it->second; |
| dependents.erase( |
| std::remove_if( |
| dependents.begin(), |
| dependents.end(), |
| [&method_headers](MethodAndMethodHeaderPair& dependent) { |
| return method_headers.find(dependent.second) != method_headers.end(); |
| }), |
| dependents.end()); |
| |
| // Remove the map entry if there are no more dependents. |
| if (dependents.empty()) { |
| map_it = cha_dependency_map_.erase(map_it); |
| } else { |
| map_it++; |
| } |
| } |
| } |
| |
| // This stack visitor walks the stack and for compiled code with certain method |
| // headers, sets the should_deoptimize flag on stack to 1. |
| // TODO: also set the register value to 1 when should_deoptimize is allocated in |
| // a register. |
| class CHAStackVisitor FINAL : public StackVisitor { |
| public: |
| CHAStackVisitor(Thread* thread_in, |
| Context* context, |
| const std::unordered_set<OatQuickMethodHeader*>& method_headers) |
| : StackVisitor(thread_in, context, StackVisitor::StackWalkKind::kSkipInlinedFrames), |
| method_headers_(method_headers) { |
| } |
| |
| bool VisitFrame() OVERRIDE REQUIRES_SHARED(Locks::mutator_lock_) { |
| ArtMethod* method = GetMethod(); |
| // Avoid types of methods that do not have an oat quick method header. |
| if (method == nullptr || |
| method->IsRuntimeMethod() || |
| method->IsNative() || |
| method->IsProxyMethod()) { |
| return true; |
| } |
| if (GetCurrentQuickFrame() == nullptr) { |
| // Not compiled code. |
| return true; |
| } |
| // Method may have multiple versions of compiled code. Check |
| // the method header to see if it has should_deoptimize flag. |
| const OatQuickMethodHeader* method_header = GetCurrentOatQuickMethodHeader(); |
| DCHECK(method_header != nullptr); |
| if (!method_header->HasShouldDeoptimizeFlag()) { |
| // This compiled version doesn't have should_deoptimize flag. Skip. |
| return true; |
| } |
| auto it = std::find(method_headers_.begin(), method_headers_.end(), method_header); |
| if (it == method_headers_.end()) { |
| // Not in the list of method headers that should be deoptimized. |
| return true; |
| } |
| |
| // The compiled code on stack is not valid anymore. Need to deoptimize. |
| SetShouldDeoptimizeFlag(); |
| |
| return true; |
| } |
| |
| private: |
| void SetShouldDeoptimizeFlag() REQUIRES_SHARED(Locks::mutator_lock_) { |
| QuickMethodFrameInfo frame_info = GetCurrentQuickFrameInfo(); |
| size_t frame_size = frame_info.FrameSizeInBytes(); |
| uint8_t* sp = reinterpret_cast<uint8_t*>(GetCurrentQuickFrame()); |
| size_t core_spill_size = POPCOUNT(frame_info.CoreSpillMask()) * |
| GetBytesPerGprSpillLocation(kRuntimeISA); |
| size_t fpu_spill_size = POPCOUNT(frame_info.FpSpillMask()) * |
| GetBytesPerFprSpillLocation(kRuntimeISA); |
| size_t offset = frame_size - core_spill_size - fpu_spill_size - kShouldDeoptimizeFlagSize; |
| uint8_t* should_deoptimize_addr = sp + offset; |
| // Set deoptimization flag to 1. |
| DCHECK(*should_deoptimize_addr == 0 || *should_deoptimize_addr == 1); |
| *should_deoptimize_addr = 1; |
| } |
| |
| // Set of method headers for compiled code that should be deoptimized. |
| const std::unordered_set<OatQuickMethodHeader*>& method_headers_; |
| |
| DISALLOW_COPY_AND_ASSIGN(CHAStackVisitor); |
| }; |
| |
| class CHACheckpoint FINAL : public Closure { |
| public: |
| explicit CHACheckpoint(const std::unordered_set<OatQuickMethodHeader*>& method_headers) |
| : barrier_(0), |
| method_headers_(method_headers) {} |
| |
| void Run(Thread* thread) OVERRIDE { |
| // Note thread and self may not be equal if thread was already suspended at |
| // the point of the request. |
| Thread* self = Thread::Current(); |
| ScopedObjectAccess soa(self); |
| CHAStackVisitor visitor(thread, nullptr, method_headers_); |
| visitor.WalkStack(); |
| barrier_.Pass(self); |
| } |
| |
| void WaitForThreadsToRunThroughCheckpoint(size_t threads_running_checkpoint) { |
| Thread* self = Thread::Current(); |
| ScopedThreadStateChange tsc(self, kWaitingForCheckPointsToRun); |
| barrier_.Increment(self, threads_running_checkpoint); |
| } |
| |
| private: |
| // The barrier to be passed through and for the requestor to wait upon. |
| Barrier barrier_; |
| // List of method headers for invalidated compiled code. |
| const std::unordered_set<OatQuickMethodHeader*>& method_headers_; |
| |
| DISALLOW_COPY_AND_ASSIGN(CHACheckpoint); |
| }; |
| |
| void ClassHierarchyAnalysis::VerifyNonSingleImplementation(mirror::Class* verify_class, |
| uint16_t verify_index, |
| ArtMethod* excluded_method) { |
| // Grab cha_lock_ to make sure all single-implementation updates are seen. |
| PointerSize image_pointer_size = |
| Runtime::Current()->GetClassLinker()->GetImagePointerSize(); |
| MutexLock cha_mu(Thread::Current(), *Locks::cha_lock_); |
| while (verify_class != nullptr) { |
| if (verify_index >= verify_class->GetVTableLength()) { |
| return; |
| } |
| ArtMethod* verify_method = verify_class->GetVTableEntry(verify_index, image_pointer_size); |
| if (verify_method != excluded_method) { |
| DCHECK(!verify_method->HasSingleImplementation()) |
| << "class: " << verify_class->PrettyClass() |
| << " verify_method: " << verify_method->PrettyMethod(true) |
| << " excluded_method: " << excluded_method->PrettyMethod(true); |
| if (verify_method->IsAbstract()) { |
| DCHECK(verify_method->GetSingleImplementation(image_pointer_size) == nullptr); |
| } |
| } |
| verify_class = verify_class->GetSuperClass(); |
| } |
| } |
| |
| void ClassHierarchyAnalysis::CheckVirtualMethodSingleImplementationInfo( |
| Handle<mirror::Class> klass, |
| ArtMethod* virtual_method, |
| ArtMethod* method_in_super, |
| std::unordered_set<ArtMethod*>& invalidated_single_impl_methods, |
| PointerSize pointer_size) { |
| // TODO: if klass is not instantiable, virtual_method isn't invocable yet so |
| // even if it overrides, it doesn't invalidate single-implementation |
| // assumption. |
| |
| DCHECK((virtual_method != method_in_super) || virtual_method->IsAbstract()); |
| DCHECK(method_in_super->GetDeclaringClass()->IsResolved()) << "class isn't resolved"; |
| // If virtual_method doesn't come from a default interface method, it should |
| // be supplied by klass. |
| DCHECK(virtual_method == method_in_super || |
| virtual_method->IsCopied() || |
| virtual_method->GetDeclaringClass() == klass.Get()); |
| |
| // To make updating single-implementation flags simple, we always maintain the following |
| // invariant: |
| // Say all virtual methods in the same vtable slot, starting from the bottom child class |
| // to super classes, is a sequence of unique methods m3, m2, m1, ... (after removing duplicate |
| // methods for inherited methods). |
| // For example for the following class hierarchy, |
| // class A { void m() { ... } } |
| // class B extends A { void m() { ... } } |
| // class C extends B {} |
| // class D extends C { void m() { ... } } |
| // the sequence is D.m(), B.m(), A.m(). |
| // The single-implementation status for that sequence of methods begin with one or two true's, |
| // then become all falses. The only case where two true's are possible is for one abstract |
| // method m and one non-abstract method mImpl that overrides method m. |
| // With the invariant, when linking in a new class, we only need to at most update one or |
| // two methods in the sequence for their single-implementation status, in order to maintain |
| // the invariant. |
| |
| if (!method_in_super->HasSingleImplementation()) { |
| // method_in_super already has multiple implementations. All methods in the |
| // same vtable slots in its super classes should have |
| // non-single-implementation already. |
| if (kIsDebugBuild) { |
| VerifyNonSingleImplementation(klass->GetSuperClass()->GetSuperClass(), |
| method_in_super->GetMethodIndex(), |
| nullptr /* excluded_method */); |
| } |
| return; |
| } |
| |
| uint16_t method_index = method_in_super->GetMethodIndex(); |
| if (method_in_super->IsAbstract()) { |
| if (kIsDebugBuild) { |
| // An abstract method should have made all methods in the same vtable |
| // slot above it in the class hierarchy having non-single-implementation. |
| mirror::Class* super_super = klass->GetSuperClass()->GetSuperClass(); |
| VerifyNonSingleImplementation(super_super, |
| method_index, |
| method_in_super); |
| } |
| |
| if (virtual_method->IsAbstract()) { |
| // SUPER: abstract, VIRTUAL: abstract. |
| if (method_in_super == virtual_method) { |
| DCHECK(klass->IsInstantiable()); |
| // An instantiable subclass hasn't provided a concrete implementation of |
| // the abstract method. Invoking method_in_super may throw AbstractMethodError. |
| // This is an uncommon case, so we simply treat method_in_super as not |
| // having single-implementation. |
| invalidated_single_impl_methods.insert(method_in_super); |
| return; |
| } else { |
| // One abstract method overrides another abstract method. This is an uncommon |
| // case. We simply treat method_in_super as not having single-implementation. |
| invalidated_single_impl_methods.insert(method_in_super); |
| return; |
| } |
| } else { |
| // SUPER: abstract, VIRTUAL: non-abstract. |
| // A non-abstract method overrides an abstract method. |
| if (method_in_super->GetSingleImplementation(pointer_size) == nullptr) { |
| // Abstract method_in_super has no implementation yet. |
| // We need to grab cha_lock_ since there may be multiple class linking |
| // going on that can check/modify the single-implementation flag/method |
| // of method_in_super. |
| MutexLock cha_mu(Thread::Current(), *Locks::cha_lock_); |
| if (!method_in_super->HasSingleImplementation()) { |
| return; |
| } |
| if (method_in_super->GetSingleImplementation(pointer_size) == nullptr) { |
| // virtual_method becomes the first implementation for method_in_super. |
| method_in_super->SetSingleImplementation(virtual_method, pointer_size); |
| // Keep method_in_super's single-implementation status. |
| return; |
| } |
| // Fall through to invalidate method_in_super's single-implementation status. |
| } |
| // Abstract method_in_super already got one implementation. |
| // Invalidate method_in_super's single-implementation status. |
| invalidated_single_impl_methods.insert(method_in_super); |
| return; |
| } |
| } else { |
| if (virtual_method->IsAbstract()) { |
| // SUPER: non-abstract, VIRTUAL: abstract. |
| // An abstract method overrides a non-abstract method. This is an uncommon |
| // case, we simply treat both methods as not having single-implementation. |
| invalidated_single_impl_methods.insert(virtual_method); |
| // Fall-through to handle invalidating method_in_super of its |
| // single-implementation status. |
| } |
| |
| // SUPER: non-abstract, VIRTUAL: non-abstract/abstract(fall-through from previous if). |
| // Invalidate method_in_super's single-implementation status. |
| invalidated_single_impl_methods.insert(method_in_super); |
| |
| // method_in_super might be the single-implementation of another abstract method, |
| // which should be also invalidated of its single-implementation status. |
| mirror::Class* super_super = klass->GetSuperClass()->GetSuperClass(); |
| while (super_super != nullptr && |
| method_index < super_super->GetVTableLength()) { |
| ArtMethod* method_in_super_super = super_super->GetVTableEntry(method_index, pointer_size); |
| if (method_in_super_super != method_in_super) { |
| if (method_in_super_super->IsAbstract()) { |
| if (method_in_super_super->HasSingleImplementation()) { |
| // Invalidate method_in_super's single-implementation status. |
| invalidated_single_impl_methods.insert(method_in_super_super); |
| // No need to further traverse up the class hierarchy since if there |
| // are cases that one abstract method overrides another method, we |
| // should have made that method having non-single-implementation already. |
| } else { |
| // method_in_super_super is already non-single-implementation. |
| // No need to further traverse up the class hierarchy. |
| } |
| } else { |
| DCHECK(!method_in_super_super->HasSingleImplementation()); |
| // No need to further traverse up the class hierarchy since two non-abstract |
| // methods (method_in_super and method_in_super_super) should have set all |
| // other methods (abstract or not) in the vtable slot to be non-single-implementation. |
| } |
| |
| if (kIsDebugBuild) { |
| VerifyNonSingleImplementation(super_super->GetSuperClass(), |
| method_index, |
| method_in_super_super); |
| } |
| // No need to go any further. |
| return; |
| } else { |
| super_super = super_super->GetSuperClass(); |
| } |
| } |
| } |
| } |
| |
| void ClassHierarchyAnalysis::CheckInterfaceMethodSingleImplementationInfo( |
| Handle<mirror::Class> klass, |
| ArtMethod* interface_method, |
| ArtMethod* implementation_method, |
| std::unordered_set<ArtMethod*>& invalidated_single_impl_methods, |
| PointerSize pointer_size) { |
| DCHECK(klass->IsInstantiable()); |
| DCHECK(interface_method->IsAbstract() || interface_method->IsDefault()); |
| |
| if (!interface_method->HasSingleImplementation()) { |
| return; |
| } |
| |
| if (implementation_method->IsAbstract()) { |
| // An instantiable class doesn't supply an implementation for |
| // interface_method. Invoking the interface method on the class will throw |
| // AbstractMethodError. This is an uncommon case, so we simply treat |
| // interface_method as not having single-implementation. |
| invalidated_single_impl_methods.insert(interface_method); |
| return; |
| } |
| |
| // We need to grab cha_lock_ since there may be multiple class linking going |
| // on that can check/modify the single-implementation flag/method of |
| // interface_method. |
| MutexLock cha_mu(Thread::Current(), *Locks::cha_lock_); |
| // Do this check again after we grab cha_lock_. |
| if (!interface_method->HasSingleImplementation()) { |
| return; |
| } |
| |
| ArtMethod* single_impl = interface_method->GetSingleImplementation(pointer_size); |
| if (single_impl == nullptr) { |
| // implementation_method becomes the first implementation for |
| // interface_method. |
| interface_method->SetSingleImplementation(implementation_method, pointer_size); |
| // Keep interface_method's single-implementation status. |
| return; |
| } |
| DCHECK(!single_impl->IsAbstract()); |
| if (single_impl->GetDeclaringClass() == implementation_method->GetDeclaringClass()) { |
| // Same implementation. Since implementation_method may be a copy of a default |
| // method, we need to check the declaring class for equality. |
| return; |
| } |
| // Another implementation for interface_method. |
| invalidated_single_impl_methods.insert(interface_method); |
| } |
| |
| void ClassHierarchyAnalysis::InitSingleImplementationFlag(Handle<mirror::Class> klass, |
| ArtMethod* method, |
| PointerSize pointer_size) { |
| DCHECK(method->IsCopied() || method->GetDeclaringClass() == klass.Get()); |
| if (klass->IsFinal() || method->IsFinal()) { |
| // Final classes or methods do not need CHA for devirtualization. |
| // This frees up modifier bits for intrinsics which currently are only |
| // used for static methods or methods of final classes. |
| return; |
| } |
| if (method->IsAbstract()) { |
| // single-implementation of abstract method shares the same field |
| // that's used for JNI function of native method. It's fine since a method |
| // cannot be both abstract and native. |
| DCHECK(!method->IsNative()) << "Abstract method cannot be native"; |
| |
| if (method->GetDeclaringClass()->IsInstantiable()) { |
| // Rare case, but we do accept it (such as 800-smali/smali/b_26143249.smali). |
| // Do not attempt to devirtualize it. |
| method->SetHasSingleImplementation(false); |
| DCHECK(method->GetSingleImplementation(pointer_size) == nullptr); |
| } else { |
| // Abstract method starts with single-implementation flag set and null |
| // implementation method. |
| method->SetHasSingleImplementation(true); |
| DCHECK(method->GetSingleImplementation(pointer_size) == nullptr); |
| } |
| } else { |
| method->SetHasSingleImplementation(true); |
| // Single implementation of non-abstract method is itself. |
| DCHECK_EQ(method->GetSingleImplementation(pointer_size), method); |
| } |
| } |
| |
| void ClassHierarchyAnalysis::UpdateAfterLoadingOf(Handle<mirror::Class> klass) { |
| PointerSize image_pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize(); |
| if (klass->IsInterface()) { |
| for (ArtMethod& method : klass->GetDeclaredVirtualMethods(image_pointer_size)) { |
| DCHECK(method.IsAbstract() || method.IsDefault()); |
| InitSingleImplementationFlag(klass, &method, image_pointer_size); |
| } |
| return; |
| } |
| |
| mirror::Class* super_class = klass->GetSuperClass(); |
| if (super_class == nullptr) { |
| return; |
| } |
| |
| // Keeps track of all methods whose single-implementation assumption |
| // is invalidated by linking `klass`. |
| std::unordered_set<ArtMethod*> invalidated_single_impl_methods; |
| |
| // Do an entry-by-entry comparison of vtable contents with super's vtable. |
| for (int32_t i = 0; i < super_class->GetVTableLength(); ++i) { |
| ArtMethod* method = klass->GetVTableEntry(i, image_pointer_size); |
| ArtMethod* method_in_super = super_class->GetVTableEntry(i, image_pointer_size); |
| if (method == method_in_super) { |
| // vtable slot entry is inherited from super class. |
| if (method->IsAbstract() && klass->IsInstantiable()) { |
| // An instantiable class that inherits an abstract method is treated as |
| // supplying an implementation that throws AbstractMethodError. |
| CheckVirtualMethodSingleImplementationInfo(klass, |
| method, |
| method_in_super, |
| invalidated_single_impl_methods, |
| image_pointer_size); |
| } |
| continue; |
| } |
| InitSingleImplementationFlag(klass, method, image_pointer_size); |
| CheckVirtualMethodSingleImplementationInfo(klass, |
| method, |
| method_in_super, |
| invalidated_single_impl_methods, |
| image_pointer_size); |
| } |
| // For new virtual methods that don't override. |
| for (int32_t i = super_class->GetVTableLength(); i < klass->GetVTableLength(); ++i) { |
| ArtMethod* method = klass->GetVTableEntry(i, image_pointer_size); |
| InitSingleImplementationFlag(klass, method, image_pointer_size); |
| } |
| |
| if (klass->IsInstantiable()) { |
| auto* iftable = klass->GetIfTable(); |
| const size_t ifcount = klass->GetIfTableCount(); |
| for (size_t i = 0; i < ifcount; ++i) { |
| mirror::Class* interface = iftable->GetInterface(i); |
| for (size_t j = 0, count = iftable->GetMethodArrayCount(i); j < count; ++j) { |
| ArtMethod* interface_method = interface->GetVirtualMethod(j, image_pointer_size); |
| mirror::PointerArray* method_array = iftable->GetMethodArray(i); |
| ArtMethod* implementation_method = |
| method_array->GetElementPtrSize<ArtMethod*>(j, image_pointer_size); |
| DCHECK(implementation_method != nullptr) << klass->PrettyClass(); |
| CheckInterfaceMethodSingleImplementationInfo(klass, |
| interface_method, |
| implementation_method, |
| invalidated_single_impl_methods, |
| image_pointer_size); |
| } |
| } |
| } |
| |
| InvalidateSingleImplementationMethods(invalidated_single_impl_methods); |
| } |
| |
| void ClassHierarchyAnalysis::InvalidateSingleImplementationMethods( |
| std::unordered_set<ArtMethod*>& invalidated_single_impl_methods) { |
| if (!invalidated_single_impl_methods.empty()) { |
| Runtime* const runtime = Runtime::Current(); |
| Thread *self = Thread::Current(); |
| // Method headers for compiled code to be invalidated. |
| std::unordered_set<OatQuickMethodHeader*> dependent_method_headers; |
| PointerSize image_pointer_size = |
| Runtime::Current()->GetClassLinker()->GetImagePointerSize(); |
| |
| { |
| // We do this under cha_lock_. Committing code also grabs this lock to |
| // make sure the code is only committed when all single-implementation |
| // assumptions are still true. |
| MutexLock cha_mu(self, *Locks::cha_lock_); |
| // Invalidate compiled methods that assume some virtual calls have only |
| // single implementations. |
| for (ArtMethod* invalidated : invalidated_single_impl_methods) { |
| if (!invalidated->HasSingleImplementation()) { |
| // It might have been invalidated already when other class linking is |
| // going on. |
| continue; |
| } |
| invalidated->SetHasSingleImplementation(false); |
| if (invalidated->IsAbstract()) { |
| // Clear the single implementation method. |
| invalidated->SetSingleImplementation(nullptr, image_pointer_size); |
| } |
| |
| if (runtime->IsAotCompiler()) { |
| // No need to invalidate any compiled code as the AotCompiler doesn't |
| // run any code. |
| continue; |
| } |
| |
| // Invalidate all dependents. |
| for (const auto& dependent : GetDependents(invalidated)) { |
| ArtMethod* method = dependent.first;; |
| OatQuickMethodHeader* method_header = dependent.second; |
| VLOG(class_linker) << "CHA invalidated compiled code for " << method->PrettyMethod(); |
| DCHECK(runtime->UseJitCompilation()); |
| runtime->GetJit()->GetCodeCache()->InvalidateCompiledCodeFor( |
| method, method_header); |
| dependent_method_headers.insert(method_header); |
| } |
| RemoveAllDependenciesFor(invalidated); |
| } |
| } |
| |
| if (dependent_method_headers.empty()) { |
| return; |
| } |
| // Deoptimze compiled code on stack that should have been invalidated. |
| CHACheckpoint checkpoint(dependent_method_headers); |
| size_t threads_running_checkpoint = runtime->GetThreadList()->RunCheckpoint(&checkpoint); |
| if (threads_running_checkpoint != 0) { |
| checkpoint.WaitForThreadsToRunThroughCheckpoint(threads_running_checkpoint); |
| } |
| } |
| } |
| |
| } // namespace art |