1169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// Copyright 2013 the V8 project authors. All rights reserved. 2169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// Redistribution and use in source and binary forms, with or without 3169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// modification, are permitted provided that the following conditions are 4169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// met: 5169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// 6169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// * Redistributions of source code must retain the above copyright 7169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// notice, this list of conditions and the following disclaimer. 8169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// * Redistributions in binary form must reproduce the above 9169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// copyright notice, this list of conditions and the following 10169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// disclaimer in the documentation and/or other materials provided 11169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// with the distribution. 12169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// * Neither the name of Google Inc. nor the names of its 13169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// contributors may be used to endorse or promote products derived 14169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// from this software without specific prior written permission. 15169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// 16169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org 28169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org#include "hydrogen-removable-simulates.h" 29169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org 30169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.orgnamespace v8 { 31169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.orgnamespace internal { 32169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org 33169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.orgvoid HMergeRemovableSimulatesPhase::Run() { 34169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org ZoneList<HSimulate*> mergelist(2, zone()); 35169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org for (int i = 0; i < graph()->blocks()->length(); ++i) { 36169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org HBasicBlock* block = graph()->blocks()->at(i); 37169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // Make sure the merge list is empty at the start of a block. 38169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org ASSERT(mergelist.is_empty()); 39169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // Nasty heuristic: Never remove the first simulate in a block. This 40169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // just so happens to have a beneficial effect on register allocation. 41169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org bool first = true; 42169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org for (HInstructionIterator it(block); !it.Done(); it.Advance()) { 43169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org HInstruction* current = it.Current(); 44169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org if (current->IsLeaveInlined()) { 45169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // Never fold simulates from inlined environments into simulates 46169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // in the outer environment. 47169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // (Before each HEnterInlined, there is a non-foldable HSimulate 48169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // anyway, so we get the barrier in the other direction for free.) 49169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // Simply remove all accumulated simulates without merging. This 50169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // is safe because simulates after instructions with side effects 51169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // are never added to the merge list. 52169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org while (!mergelist.is_empty()) { 53169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org mergelist.RemoveLast()->DeleteAndReplaceWith(NULL); 54169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } 55169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org continue; 56169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } 57169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org if (current->IsReturn()) { 58169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // Drop mergeable simulates in the list. This is safe because 59169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // simulates after instructions with side effects are never added 60169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // to the merge list. 61169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org while (!mergelist.is_empty()) { 62169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org mergelist.RemoveLast()->DeleteAndReplaceWith(NULL); 63169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } 64169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org continue; 65169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } 66169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // Skip the non-simulates and the first simulate. 67169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org if (!current->IsSimulate()) continue; 68169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org if (first) { 69169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org first = false; 70169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org continue; 71169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } 72169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org HSimulate* current_simulate = HSimulate::cast(current); 73169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org if ((current_simulate->previous()->HasObservableSideEffects() && 74169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org !current_simulate->next()->IsSimulate()) || 75169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org !current_simulate->is_candidate_for_removal()) { 76169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // This simulate is not suitable for folding. 77169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // Fold the ones accumulated so far. 78169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org current_simulate->MergeWith(&mergelist); 79169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org continue; 80169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } else { 81169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // Accumulate this simulate for folding later on. 82169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org mergelist.Add(current_simulate, zone()); 83169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } 84169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } 85169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org 86169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org if (!mergelist.is_empty()) { 87169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org // Merge the accumulated simulates at the end of the block. 88169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org HSimulate* last = mergelist.RemoveLast(); 89169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org last->MergeWith(&mergelist); 90169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } 91169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org } 92169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org} 93169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org 94169691d93a961c8b511f8ac8fd8ee33d081ca10fdanno@chromium.org} } // namespace v8::internal 95