| /* |
| * 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 "inliner.h" |
| |
| #include "art_method-inl.h" |
| #include "builder.h" |
| #include "class_linker.h" |
| #include "constant_folding.h" |
| #include "dead_code_elimination.h" |
| #include "driver/compiler_driver-inl.h" |
| #include "driver/dex_compilation_unit.h" |
| #include "instruction_simplifier.h" |
| #include "mirror/class_loader.h" |
| #include "mirror/dex_cache.h" |
| #include "nodes.h" |
| #include "optimizing_compiler.h" |
| #include "reference_type_propagation.h" |
| #include "register_allocator.h" |
| #include "ssa_phi_elimination.h" |
| #include "scoped_thread_state_change.h" |
| #include "thread.h" |
| #include "dex/verified_method.h" |
| #include "dex/verification_results.h" |
| |
| namespace art { |
| |
| static constexpr int kMaxInlineCodeUnits = 18; |
| static constexpr int kDepthLimit = 3; |
| |
| void HInliner::Run() { |
| if (graph_->IsDebuggable()) { |
| // For simplicity, we currently never inline when the graph is debuggable. This avoids |
| // doing some logic in the runtime to discover if a method could have been inlined. |
| return; |
| } |
| const GrowableArray<HBasicBlock*>& blocks = graph_->GetReversePostOrder(); |
| HBasicBlock* next_block = blocks.Get(0); |
| for (size_t i = 0; i < blocks.Size(); ++i) { |
| // Because we are changing the graph when inlining, we need to remember the next block. |
| // This avoids doing the inlining work again on the inlined blocks. |
| if (blocks.Get(i) != next_block) { |
| continue; |
| } |
| HBasicBlock* block = next_block; |
| next_block = (i == blocks.Size() - 1) ? nullptr : blocks.Get(i + 1); |
| for (HInstruction* instruction = block->GetFirstInstruction(); instruction != nullptr;) { |
| HInstruction* next = instruction->GetNext(); |
| HInvoke* call = instruction->AsInvoke(); |
| // As long as the call is not intrinsified, it is worth trying to inline. |
| if (call != nullptr && call->GetIntrinsic() == Intrinsics::kNone) { |
| // We use the original invoke type to ensure the resolution of the called method |
| // works properly. |
| if (!TryInline(call, call->GetDexMethodIndex())) { |
| if (kIsDebugBuild && IsCompilingWithCoreImage()) { |
| std::string callee_name = |
| PrettyMethod(call->GetDexMethodIndex(), *outer_compilation_unit_.GetDexFile()); |
| bool should_inline = callee_name.find("$inline$") != std::string::npos; |
| CHECK(!should_inline) << "Could not inline " << callee_name; |
| } |
| } else { |
| if (kIsDebugBuild && IsCompilingWithCoreImage()) { |
| std::string callee_name = |
| PrettyMethod(call->GetDexMethodIndex(), *outer_compilation_unit_.GetDexFile()); |
| bool must_not_inline = callee_name.find("$noinline$") != std::string::npos; |
| CHECK(!must_not_inline) << "Should not have inlined " << callee_name; |
| } |
| } |
| } |
| instruction = next; |
| } |
| } |
| } |
| |
| static bool IsMethodOrDeclaringClassFinal(ArtMethod* method) |
| SHARED_REQUIRES(Locks::mutator_lock_) { |
| return method->IsFinal() || method->GetDeclaringClass()->IsFinal(); |
| } |
| |
| /** |
| * Given the `resolved_method` looked up in the dex cache, try to find |
| * the actual runtime target of an interface or virtual call. |
| * Return nullptr if the runtime target cannot be proven. |
| */ |
| static ArtMethod* FindVirtualOrInterfaceTarget(HInvoke* invoke, ArtMethod* resolved_method) |
| SHARED_REQUIRES(Locks::mutator_lock_) { |
| if (IsMethodOrDeclaringClassFinal(resolved_method)) { |
| // No need to lookup further, the resolved method will be the target. |
| return resolved_method; |
| } |
| |
| HInstruction* receiver = invoke->InputAt(0); |
| if (receiver->IsNullCheck()) { |
| // Due to multiple levels of inlining within the same pass, it might be that |
| // null check does not have the reference type of the actual receiver. |
| receiver = receiver->InputAt(0); |
| } |
| ReferenceTypeInfo info = receiver->GetReferenceTypeInfo(); |
| if (info.IsTop()) { |
| // We have no information on the receiver. |
| return nullptr; |
| } else if (!info.IsExact()) { |
| // We currently only support inlining with known receivers. |
| // TODO: Remove this check, we should be able to inline final methods |
| // on unknown receivers. |
| return nullptr; |
| } else if (info.GetTypeHandle()->IsInterface()) { |
| // Statically knowing that the receiver has an interface type cannot |
| // help us find what is the target method. |
| return nullptr; |
| } else if (!resolved_method->GetDeclaringClass()->IsAssignableFrom(info.GetTypeHandle().Get())) { |
| // The method that we're trying to call is not in the receiver's class or super classes. |
| return nullptr; |
| } |
| |
| ClassLinker* cl = Runtime::Current()->GetClassLinker(); |
| size_t pointer_size = cl->GetImagePointerSize(); |
| if (invoke->IsInvokeInterface()) { |
| resolved_method = info.GetTypeHandle()->FindVirtualMethodForInterface( |
| resolved_method, pointer_size); |
| } else { |
| DCHECK(invoke->IsInvokeVirtual()); |
| resolved_method = info.GetTypeHandle()->FindVirtualMethodForVirtual( |
| resolved_method, pointer_size); |
| } |
| |
| if (resolved_method == nullptr) { |
| // The information we had on the receiver was not enough to find |
| // the target method. Since we check above the exact type of the receiver, |
| // the only reason this can happen is an IncompatibleClassChangeError. |
| return nullptr; |
| } else if (resolved_method->IsAbstract()) { |
| // The information we had on the receiver was not enough to find |
| // the target method. Since we check above the exact type of the receiver, |
| // the only reason this can happen is an IncompatibleClassChangeError. |
| return nullptr; |
| } else if (IsMethodOrDeclaringClassFinal(resolved_method)) { |
| // A final method has to be the target method. |
| return resolved_method; |
| } else if (info.IsExact()) { |
| // If we found a method and the receiver's concrete type is statically |
| // known, we know for sure the target. |
| return resolved_method; |
| } else { |
| // Even if we did find a method, the receiver type was not enough to |
| // statically find the runtime target. |
| return nullptr; |
| } |
| } |
| |
| static uint32_t FindMethodIndexIn(ArtMethod* method, |
| const DexFile& dex_file, |
| uint32_t referrer_index) |
| SHARED_REQUIRES(Locks::mutator_lock_) { |
| if (method->GetDexFile()->GetLocation().compare(dex_file.GetLocation()) == 0) { |
| return method->GetDexMethodIndex(); |
| } else { |
| return method->FindDexMethodIndexInOtherDexFile(dex_file, referrer_index); |
| } |
| } |
| |
| bool HInliner::TryInline(HInvoke* invoke_instruction, uint32_t method_index) const { |
| ScopedObjectAccess soa(Thread::Current()); |
| const DexFile& caller_dex_file = *caller_compilation_unit_.GetDexFile(); |
| VLOG(compiler) << "Try inlining " << PrettyMethod(method_index, caller_dex_file); |
| |
| ClassLinker* class_linker = caller_compilation_unit_.GetClassLinker(); |
| // We can query the dex cache directly. The verifier has populated it already. |
| ArtMethod* resolved_method = class_linker->FindDexCache(caller_dex_file)->GetResolvedMethod( |
| method_index, class_linker->GetImagePointerSize()); |
| |
| if (resolved_method == nullptr) { |
| // Method cannot be resolved if it is in another dex file we do not have access to. |
| VLOG(compiler) << "Method cannot be resolved " << PrettyMethod(method_index, caller_dex_file); |
| return false; |
| } |
| |
| if (!invoke_instruction->IsInvokeStaticOrDirect()) { |
| resolved_method = FindVirtualOrInterfaceTarget(invoke_instruction, resolved_method); |
| if (resolved_method == nullptr) { |
| VLOG(compiler) << "Interface or virtual call to " |
| << PrettyMethod(method_index, caller_dex_file) |
| << " could not be statically determined"; |
| return false; |
| } |
| // We have found a method, but we need to find where that method is for the caller's |
| // dex file. |
| method_index = FindMethodIndexIn(resolved_method, caller_dex_file, method_index); |
| if (method_index == DexFile::kDexNoIndex) { |
| VLOG(compiler) << "Interface or virtual call to " |
| << PrettyMethod(resolved_method) |
| << " cannot be inlined because unaccessible to caller"; |
| return false; |
| } |
| } |
| |
| bool same_dex_file = true; |
| const DexFile& outer_dex_file = *outer_compilation_unit_.GetDexFile(); |
| if (resolved_method->GetDexFile()->GetLocation().compare(outer_dex_file.GetLocation()) != 0) { |
| same_dex_file = false; |
| } |
| |
| const DexFile::CodeItem* code_item = resolved_method->GetCodeItem(); |
| |
| if (code_item == nullptr) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file) |
| << " is not inlined because it is native"; |
| return false; |
| } |
| |
| if (code_item->insns_size_in_code_units_ > kMaxInlineCodeUnits) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file) |
| << " is too big to inline"; |
| return false; |
| } |
| |
| if (code_item->tries_size_ != 0) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file) |
| << " is not inlined because of try block"; |
| return false; |
| } |
| |
| uint16_t class_def_idx = resolved_method->GetDeclaringClass()->GetDexClassDefIndex(); |
| if (!compiler_driver_->IsMethodVerifiedWithoutFailures( |
| resolved_method->GetDexMethodIndex(), class_def_idx, *resolved_method->GetDexFile())) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file) |
| << " couldn't be verified, so it cannot be inlined"; |
| return false; |
| } |
| |
| if (resolved_method->ShouldNotInline()) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file) |
| << " was already flagged as non inlineable"; |
| return false; |
| } |
| |
| if (invoke_instruction->IsInvokeStaticOrDirect() && |
| invoke_instruction->AsInvokeStaticOrDirect()->IsStaticWithImplicitClinitCheck()) { |
| // Case of a static method that cannot be inlined because it implicitly |
| // requires an initialization check of its declaring class. |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, caller_dex_file) |
| << " is not inlined because it is static and requires a clinit" |
| << " check that cannot be emitted due to Dex cache limitations"; |
| return false; |
| } |
| |
| if (!TryBuildAndInline(resolved_method, invoke_instruction, same_dex_file)) { |
| return false; |
| } |
| |
| VLOG(compiler) << "Successfully inlined " << PrettyMethod(method_index, caller_dex_file); |
| MaybeRecordStat(kInlinedInvoke); |
| return true; |
| } |
| |
| bool HInliner::TryBuildAndInline(ArtMethod* resolved_method, |
| HInvoke* invoke_instruction, |
| bool same_dex_file) const { |
| ScopedObjectAccess soa(Thread::Current()); |
| const DexFile::CodeItem* code_item = resolved_method->GetCodeItem(); |
| const DexFile& callee_dex_file = *resolved_method->GetDexFile(); |
| uint32_t method_index = resolved_method->GetDexMethodIndex(); |
| |
| DexCompilationUnit dex_compilation_unit( |
| nullptr, |
| caller_compilation_unit_.GetClassLoader(), |
| caller_compilation_unit_.GetClassLinker(), |
| *resolved_method->GetDexFile(), |
| code_item, |
| resolved_method->GetDeclaringClass()->GetDexClassDefIndex(), |
| resolved_method->GetDexMethodIndex(), |
| resolved_method->GetAccessFlags(), |
| nullptr); |
| |
| bool requires_ctor_barrier = false; |
| |
| if (dex_compilation_unit.IsConstructor()) { |
| // If it's a super invocation and we already generate a barrier there's no need |
| // to generate another one. |
| // We identify super calls by looking at the "this" pointer. If its value is the |
| // same as the local "this" pointer then we must have a super invocation. |
| bool is_super_invocation = invoke_instruction->InputAt(0)->IsParameterValue() |
| && invoke_instruction->InputAt(0)->AsParameterValue()->IsThis(); |
| if (is_super_invocation && graph_->ShouldGenerateConstructorBarrier()) { |
| requires_ctor_barrier = false; |
| } else { |
| Thread* self = Thread::Current(); |
| requires_ctor_barrier = compiler_driver_->RequiresConstructorBarrier(self, |
| dex_compilation_unit.GetDexFile(), |
| dex_compilation_unit.GetClassDefIndex()); |
| } |
| } |
| |
| InvokeType invoke_type = invoke_instruction->GetOriginalInvokeType(); |
| if (invoke_type == kInterface) { |
| // We have statically resolved the dispatch. To please the class linker |
| // at runtime, we change this call as if it was a virtual call. |
| invoke_type = kVirtual; |
| } |
| HGraph* callee_graph = new (graph_->GetArena()) HGraph( |
| graph_->GetArena(), |
| callee_dex_file, |
| method_index, |
| requires_ctor_barrier, |
| compiler_driver_->GetInstructionSet(), |
| invoke_type, |
| graph_->IsDebuggable(), |
| graph_->GetCurrentInstructionId()); |
| |
| OptimizingCompilerStats inline_stats; |
| HGraphBuilder builder(callee_graph, |
| &dex_compilation_unit, |
| &outer_compilation_unit_, |
| resolved_method->GetDexFile(), |
| compiler_driver_, |
| &inline_stats, |
| resolved_method->GetQuickenedInfo()); |
| |
| if (!builder.BuildGraph(*code_item)) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file) |
| << " could not be built, so cannot be inlined"; |
| // There could be multiple reasons why the graph could not be built, including |
| // unaccessible methods/fields due to using a different dex cache. We do not mark |
| // the method as non-inlineable so that other callers can still try to inline it. |
| return false; |
| } |
| |
| if (!RegisterAllocator::CanAllocateRegistersFor(*callee_graph, |
| compiler_driver_->GetInstructionSet())) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file) |
| << " cannot be inlined because of the register allocator"; |
| resolved_method->SetShouldNotInline(); |
| return false; |
| } |
| |
| if (!callee_graph->TryBuildingSsa()) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file) |
| << " could not be transformed to SSA"; |
| resolved_method->SetShouldNotInline(); |
| return false; |
| } |
| |
| // Run simple optimizations on the graph. |
| HDeadCodeElimination dce(callee_graph, stats_); |
| HConstantFolding fold(callee_graph); |
| ReferenceTypePropagation type_propagation(callee_graph, handles_); |
| InstructionSimplifier simplify(callee_graph, stats_); |
| |
| HOptimization* optimizations[] = { |
| &dce, |
| &fold, |
| &type_propagation, |
| &simplify, |
| }; |
| |
| for (size_t i = 0; i < arraysize(optimizations); ++i) { |
| HOptimization* optimization = optimizations[i]; |
| optimization->Run(); |
| } |
| |
| if (depth_ + 1 < kDepthLimit) { |
| HInliner inliner(callee_graph, |
| outer_compilation_unit_, |
| dex_compilation_unit, |
| compiler_driver_, |
| handles_, |
| stats_, |
| depth_ + 1); |
| inliner.Run(); |
| } |
| |
| // TODO: We should abort only if all predecessors throw. However, |
| // HGraph::InlineInto currently does not handle an exit block with |
| // a throw predecessor. |
| HBasicBlock* exit_block = callee_graph->GetExitBlock(); |
| if (exit_block == nullptr) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file) |
| << " could not be inlined because it has an infinite loop"; |
| resolved_method->SetShouldNotInline(); |
| return false; |
| } |
| |
| bool has_throw_predecessor = false; |
| for (size_t i = 0, e = exit_block->GetPredecessors().Size(); i < e; ++i) { |
| if (exit_block->GetPredecessors().Get(i)->GetLastInstruction()->IsThrow()) { |
| has_throw_predecessor = true; |
| break; |
| } |
| } |
| if (has_throw_predecessor) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file) |
| << " could not be inlined because one branch always throws"; |
| resolved_method->SetShouldNotInline(); |
| return false; |
| } |
| |
| HReversePostOrderIterator it(*callee_graph); |
| it.Advance(); // Past the entry block, it does not contain instructions that prevent inlining. |
| for (; !it.Done(); it.Advance()) { |
| HBasicBlock* block = it.Current(); |
| if (block->IsLoopHeader()) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file) |
| << " could not be inlined because it contains a loop"; |
| resolved_method->SetShouldNotInline(); |
| return false; |
| } |
| |
| for (HInstructionIterator instr_it(block->GetInstructions()); |
| !instr_it.Done(); |
| instr_it.Advance()) { |
| HInstruction* current = instr_it.Current(); |
| |
| if (current->IsInvokeInterface()) { |
| // Disable inlining of interface calls. The cost in case of entering the |
| // resolution conflict is currently too high. |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file) |
| << " could not be inlined because it has an interface call."; |
| resolved_method->SetShouldNotInline(); |
| return false; |
| } |
| |
| if (!same_dex_file && current->NeedsEnvironment()) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file) |
| << " could not be inlined because " << current->DebugName() |
| << " needs an environment and is in a different dex file"; |
| return false; |
| } |
| |
| if (!same_dex_file && current->NeedsDexCache()) { |
| VLOG(compiler) << "Method " << PrettyMethod(method_index, callee_dex_file) |
| << " could not be inlined because " << current->DebugName() |
| << " it is in a different dex file and requires access to the dex cache"; |
| // Do not flag the method as not-inlineable. A caller within the same |
| // dex file could still successfully inline it. |
| return false; |
| } |
| } |
| } |
| |
| callee_graph->InlineInto(graph_, invoke_instruction); |
| |
| return true; |
| } |
| |
| } // namespace art |
