verwaest@chromium.org | d4be0f0 | 2013-06-05 13:39:03 +0000 | [diff] [blame] | 1 | // Copyright 2013 the V8 project authors. All rights reserved. |
| 2 | // Redistribution and use in source and binary forms, with or without |
| 3 | // modification, are permitted provided that the following conditions are |
| 4 | // met: |
| 5 | // |
| 6 | // * Redistributions of source code must retain the above copyright |
| 7 | // notice, this list of conditions and the following disclaimer. |
| 8 | // * Redistributions in binary form must reproduce the above |
| 9 | // copyright notice, this list of conditions and the following |
| 10 | // disclaimer in the documentation and/or other materials provided |
| 11 | // with the distribution. |
| 12 | // * Neither the name of Google Inc. nor the names of its |
| 13 | // contributors may be used to endorse or promote products derived |
| 14 | // from this software without specific prior written permission. |
| 15 | // |
| 16 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 17 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 20 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 21 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 22 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 26 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | |
| 28 | #ifndef V8_HYDROGEN_ENVIRONMENT_LIVENESS_H_ |
| 29 | #define V8_HYDROGEN_ENVIRONMENT_LIVENESS_H_ |
| 30 | |
| 31 | |
| 32 | #include "hydrogen.h" |
| 33 | |
| 34 | namespace v8 { |
| 35 | namespace internal { |
| 36 | |
| 37 | |
| 38 | // Trims live ranges of environment slots by doing explicit liveness analysis. |
| 39 | // Values in the environment are kept alive by every subsequent LInstruction |
| 40 | // that is assigned an LEnvironment, which creates register pressure and |
| 41 | // unnecessary spill slot moves. Therefore it is beneficial to trim the |
| 42 | // live ranges of environment slots by zapping them with a constant after |
| 43 | // the last lookup that refers to them. |
| 44 | // Slots are identified by their index and only affected if whitelisted in |
| 45 | // HOptimizedGraphBuilder::IsEligibleForEnvironmentLivenessAnalysis(). |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame] | 46 | class HEnvironmentLivenessAnalysisPhase : public HPhase { |
verwaest@chromium.org | d4be0f0 | 2013-06-05 13:39:03 +0000 | [diff] [blame] | 47 | public: |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame] | 48 | explicit HEnvironmentLivenessAnalysisPhase(HGraph* graph); |
verwaest@chromium.org | d4be0f0 | 2013-06-05 13:39:03 +0000 | [diff] [blame] | 49 | |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame] | 50 | void Run(); |
verwaest@chromium.org | d4be0f0 | 2013-06-05 13:39:03 +0000 | [diff] [blame] | 51 | |
| 52 | private: |
| 53 | void ZapEnvironmentSlot(int index, HSimulate* simulate); |
| 54 | void ZapEnvironmentSlotsInSuccessors(HBasicBlock* block, BitVector* live); |
| 55 | void ZapEnvironmentSlotsForInstruction(HEnvironmentMarker* marker); |
| 56 | void UpdateLivenessAtBlockEnd(HBasicBlock* block, BitVector* live); |
| 57 | void UpdateLivenessAtInstruction(HInstruction* instr, BitVector* live); |
| 58 | |
verwaest@chromium.org | d4be0f0 | 2013-06-05 13:39:03 +0000 | [diff] [blame] | 59 | int block_count_; |
| 60 | |
| 61 | // Largest number of local variables in any environment in the graph |
| 62 | // (including inlined environments). |
| 63 | int maximum_environment_size_; |
| 64 | |
| 65 | // Per-block data. All these lists are indexed by block_id. |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame] | 66 | ZoneList<BitVector*> live_at_block_start_; |
| 67 | ZoneList<HSimulate*> first_simulate_; |
| 68 | ZoneList<BitVector*> first_simulate_invalid_for_index_; |
verwaest@chromium.org | d4be0f0 | 2013-06-05 13:39:03 +0000 | [diff] [blame] | 69 | |
| 70 | // List of all HEnvironmentMarker instructions for quick iteration/deletion. |
| 71 | // It is populated during the first pass over the graph, controlled by |
| 72 | // |collect_markers_|. |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame] | 73 | ZoneList<HEnvironmentMarker*> markers_; |
verwaest@chromium.org | d4be0f0 | 2013-06-05 13:39:03 +0000 | [diff] [blame] | 74 | bool collect_markers_; |
| 75 | |
| 76 | // Keeps track of the last simulate seen, as well as the environment slots |
| 77 | // for which a new live range has started since (so they must not be zapped |
| 78 | // in that simulate when the end of another live range of theirs is found). |
| 79 | HSimulate* last_simulate_; |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame] | 80 | BitVector went_live_since_last_simulate_; |
| 81 | |
| 82 | DISALLOW_COPY_AND_ASSIGN(HEnvironmentLivenessAnalysisPhase); |
verwaest@chromium.org | d4be0f0 | 2013-06-05 13:39:03 +0000 | [diff] [blame] | 83 | }; |
| 84 | |
| 85 | |
| 86 | } } // namespace v8::internal |
| 87 | |
| 88 | #endif /* V8_HYDROGEN_ENVIRONMENT_LIVENESS_H_ */ |