jkummerow@chromium.org | c118402 | 2013-05-28 16:58:15 +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_GVN_H_ |
| 29 | #define V8_HYDROGEN_GVN_H_ |
| 30 | |
| 31 | #include "hydrogen.h" |
| 32 | #include "hydrogen-instructions.h" |
| 33 | #include "compiler.h" |
| 34 | #include "zone.h" |
| 35 | |
| 36 | namespace v8 { |
| 37 | namespace internal { |
| 38 | |
| 39 | // Simple sparse set with O(1) add, contains, and clear. |
| 40 | class SparseSet { |
| 41 | public: |
| 42 | SparseSet(Zone* zone, int capacity) |
| 43 | : capacity_(capacity), |
| 44 | length_(0), |
| 45 | dense_(zone->NewArray<int>(capacity)), |
| 46 | sparse_(zone->NewArray<int>(capacity)) { |
| 47 | #ifndef NVALGRIND |
| 48 | // Initialize the sparse array to make valgrind happy. |
| 49 | memset(sparse_, 0, sizeof(sparse_[0]) * capacity); |
| 50 | #endif |
| 51 | } |
| 52 | |
| 53 | bool Contains(int n) const { |
| 54 | ASSERT(0 <= n && n < capacity_); |
| 55 | int d = sparse_[n]; |
| 56 | return 0 <= d && d < length_ && dense_[d] == n; |
| 57 | } |
| 58 | |
| 59 | bool Add(int n) { |
| 60 | if (Contains(n)) return false; |
| 61 | dense_[length_] = n; |
| 62 | sparse_[n] = length_; |
| 63 | ++length_; |
| 64 | return true; |
| 65 | } |
| 66 | |
| 67 | void Clear() { length_ = 0; } |
| 68 | |
| 69 | private: |
| 70 | int capacity_; |
| 71 | int length_; |
| 72 | int* dense_; |
| 73 | int* sparse_; |
| 74 | |
| 75 | DISALLOW_COPY_AND_ASSIGN(SparseSet); |
| 76 | }; |
| 77 | |
| 78 | |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame^] | 79 | // Perform common subexpression elimination and loop-invariant code motion. |
| 80 | class HGlobalValueNumberingPhase : public HPhase { |
jkummerow@chromium.org | c118402 | 2013-05-28 16:58:15 +0000 | [diff] [blame] | 81 | public: |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame^] | 82 | explicit HGlobalValueNumberingPhase(HGraph* graph); |
jkummerow@chromium.org | c118402 | 2013-05-28 16:58:15 +0000 | [diff] [blame] | 83 | |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame^] | 84 | void Run() { |
| 85 | Analyze(); |
| 86 | // Trigger a second analysis pass to further eliminate duplicate values |
| 87 | // that could only be discovered by removing side-effect-generating |
| 88 | // instructions during the first pass. |
| 89 | if (FLAG_smi_only_arrays && removed_side_effects_) { |
| 90 | Analyze(); |
| 91 | ASSERT(!removed_side_effects_); |
| 92 | } |
| 93 | } |
jkummerow@chromium.org | c118402 | 2013-05-28 16:58:15 +0000 | [diff] [blame] | 94 | |
| 95 | private: |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame^] | 96 | void Analyze(); |
jkummerow@chromium.org | c118402 | 2013-05-28 16:58:15 +0000 | [diff] [blame] | 97 | GVNFlagSet CollectSideEffectsOnPathsToDominatedBlock( |
| 98 | HBasicBlock* dominator, |
| 99 | HBasicBlock* dominated); |
| 100 | void AnalyzeGraph(); |
| 101 | void ComputeBlockSideEffects(); |
| 102 | void LoopInvariantCodeMotion(); |
| 103 | void ProcessLoopBlock(HBasicBlock* block, |
| 104 | HBasicBlock* before_loop, |
| 105 | GVNFlagSet loop_kills, |
| 106 | GVNFlagSet* accumulated_first_time_depends, |
| 107 | GVNFlagSet* accumulated_first_time_changes); |
| 108 | bool AllowCodeMotion(); |
| 109 | bool ShouldMove(HInstruction* instr, HBasicBlock* loop_header); |
| 110 | |
jkummerow@chromium.org | c118402 | 2013-05-28 16:58:15 +0000 | [diff] [blame] | 111 | bool removed_side_effects_; |
| 112 | |
| 113 | // A map of block IDs to their side effects. |
| 114 | ZoneList<GVNFlagSet> block_side_effects_; |
| 115 | |
| 116 | // A map of loop header block IDs to their loop's side effects. |
| 117 | ZoneList<GVNFlagSet> loop_side_effects_; |
| 118 | |
| 119 | // Used when collecting side effects on paths from dominator to |
| 120 | // dominated. |
| 121 | SparseSet visited_on_paths_; |
mstarzinger@chromium.org | 1510d58 | 2013-06-28 14:00:48 +0000 | [diff] [blame^] | 122 | |
| 123 | DISALLOW_COPY_AND_ASSIGN(HGlobalValueNumberingPhase); |
jkummerow@chromium.org | c118402 | 2013-05-28 16:58:15 +0000 | [diff] [blame] | 124 | }; |
| 125 | |
| 126 | |
| 127 | } } // namespace v8::internal |
| 128 | |
| 129 | #endif // V8_HYDROGEN_GVN_H_ |