1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "side_effects_analysis.h" 18 19namespace art { 20 21void SideEffectsAnalysis::Run() { 22 // Inlining might have created more blocks, so we need to increase the size 23 // if needed. 24 block_effects_.SetSize(graph_->GetBlocks().Size()); 25 loop_effects_.SetSize(graph_->GetBlocks().Size()); 26 27 if (kIsDebugBuild) { 28 for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) { 29 HBasicBlock* block = it.Current(); 30 SideEffects effects = GetBlockEffects(block); 31 DCHECK(!effects.HasSideEffects() && !effects.HasDependencies()); 32 if (block->IsLoopHeader()) { 33 effects = GetLoopEffects(block); 34 DCHECK(!effects.HasSideEffects() && !effects.HasDependencies()); 35 } 36 } 37 } 38 39 // Do a post order visit to ensure we visit a loop header after its loop body. 40 for (HPostOrderIterator it(*graph_); !it.Done(); it.Advance()) { 41 HBasicBlock* block = it.Current(); 42 43 SideEffects effects = SideEffects::None(); 44 // Update `effects` with the side effects of all instructions in this block. 45 for (HInstructionIterator inst_it(block->GetInstructions()); !inst_it.Done(); 46 inst_it.Advance()) { 47 HInstruction* instruction = inst_it.Current(); 48 effects = effects.Union(instruction->GetSideEffects()); 49 if (effects.HasAllSideEffects()) { 50 break; 51 } 52 } 53 54 block_effects_.Put(block->GetBlockId(), effects); 55 56 if (block->IsLoopHeader()) { 57 // The side effects of the loop header are part of the loop. 58 UpdateLoopEffects(block->GetLoopInformation(), effects); 59 HBasicBlock* pre_header = block->GetLoopInformation()->GetPreHeader(); 60 if (pre_header->IsInLoop()) { 61 // Update the side effects of the outer loop with the side effects of the inner loop. 62 // Note that this works because we know all the blocks of the inner loop are visited 63 // before the loop header of the outer loop. 64 UpdateLoopEffects(pre_header->GetLoopInformation(), GetLoopEffects(block)); 65 } 66 } else if (block->IsInLoop()) { 67 // Update the side effects of the loop with the side effects of this block. 68 UpdateLoopEffects(block->GetLoopInformation(), effects); 69 } 70 } 71 has_run_ = true; 72} 73 74SideEffects SideEffectsAnalysis::GetLoopEffects(HBasicBlock* block) const { 75 DCHECK(block->IsLoopHeader()); 76 return loop_effects_.Get(block->GetBlockId()); 77} 78 79SideEffects SideEffectsAnalysis::GetBlockEffects(HBasicBlock* block) const { 80 return block_effects_.Get(block->GetBlockId()); 81} 82 83void SideEffectsAnalysis::UpdateLoopEffects(HLoopInformation* info, SideEffects effects) { 84 int id = info->GetHeader()->GetBlockId(); 85 loop_effects_.Put(id, loop_effects_.Get(id).Union(effects)); 86} 87 88} // namespace art 89