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1 // Copyright 2013 the V8 project authors. All rights reserved. | 1 // Copyright 2013 the V8 project authors. All rights reserved. |
2 // Redistribution and use in source and binary forms, with or without | 2 // Redistribution and use in source and binary forms, with or without |
3 // modification, are permitted provided that the following conditions are | 3 // modification, are permitted provided that the following conditions are |
4 // met: | 4 // met: |
5 // | 5 // |
6 // * Redistributions of source code must retain the above copyright | 6 // * Redistributions of source code must retain the above copyright |
7 // notice, this list of conditions and the following disclaimer. | 7 // notice, this list of conditions and the following disclaimer. |
8 // * Redistributions in binary form must reproduce the above | 8 // * Redistributions in binary form must reproduce the above |
9 // copyright notice, this list of conditions and the following | 9 // copyright notice, this list of conditions and the following |
10 // disclaimer in the documentation and/or other materials provided | 10 // disclaimer in the documentation and/or other materials provided |
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29 #define V8_HYDROGEN_GVN_H_ | 29 #define V8_HYDROGEN_GVN_H_ |
30 | 30 |
31 #include "hydrogen.h" | 31 #include "hydrogen.h" |
32 #include "hydrogen-instructions.h" | 32 #include "hydrogen-instructions.h" |
33 #include "compiler.h" | 33 #include "compiler.h" |
34 #include "zone.h" | 34 #include "zone.h" |
35 | 35 |
36 namespace v8 { | 36 namespace v8 { |
37 namespace internal { | 37 namespace internal { |
38 | 38 |
| 39 // This class extends GVNFlagSet with additional "special" dynamic side effects, |
| 40 // which can be used to represent side effects that cannot be expressed using |
| 41 // the GVNFlags of an HInstruction. These special side effects are tracked by a |
| 42 // SideEffectsTracker (see below). |
| 43 class SideEffects V8_FINAL { |
| 44 public: |
| 45 static const int kNumberOfSpecials = 64 - kNumberOfFlags; |
| 46 |
| 47 SideEffects() : bits_(0) {} |
| 48 explicit SideEffects(GVNFlagSet flags) : bits_(flags.ToIntegral()) {} |
| 49 bool IsEmpty() const { return bits_ == 0; } |
| 50 bool ContainsFlag(GVNFlag flag) const { |
| 51 return (bits_ & MaskFlag(flag)) != 0; |
| 52 } |
| 53 bool ContainsSpecial(int special) const { |
| 54 return (bits_ & MaskSpecial(special)) != 0; |
| 55 } |
| 56 bool ContainsAnyOf(SideEffects set) const { return (bits_ & set.bits_) != 0; } |
| 57 void Add(SideEffects set) { bits_ |= set.bits_; } |
| 58 void AddSpecial(int special) { bits_ |= MaskSpecial(special); } |
| 59 void AddAllSpecial() { bits_ |= ~static_cast<uint64_t>(0) << kNumberOfFlags; } |
| 60 void RemoveFlag(GVNFlag flag) { bits_ &= ~MaskFlag(flag); } |
| 61 void RemoveAll() { bits_ = 0; } |
| 62 uint64_t ToIntegral() const { return bits_; } |
| 63 void PrintTo(StringStream* stream) const; |
| 64 |
| 65 private: |
| 66 uint64_t MaskFlag(GVNFlag flag) const { |
| 67 return static_cast<uint64_t>(1) << static_cast<unsigned>(flag); |
| 68 } |
| 69 uint64_t MaskSpecial(int special) const { |
| 70 ASSERT(special >= 0); |
| 71 ASSERT(special < kNumberOfSpecials); |
| 72 return static_cast<uint64_t>(1) << static_cast<unsigned>( |
| 73 special + kNumberOfFlags); |
| 74 } |
| 75 |
| 76 uint64_t bits_; |
| 77 STATIC_ASSERT(kNumberOfFlags + kNumberOfSpecials == sizeof(bits_) * CHAR_BIT); |
| 78 }; |
| 79 |
| 80 |
| 81 // Tracks inobject field loads/stores in a fine grained fashion, and represents |
| 82 // them using the "special" dynamic side effects of the SideEffects class (see |
| 83 // above). This way unrelated inobject field stores don't prevent hoisting and |
| 84 // merging of inobject field loads. |
| 85 class SideEffectsTracker V8_FINAL BASE_EMBEDDED { |
| 86 public: |
| 87 SideEffectsTracker() : num_inobject_fields_(0) {} |
| 88 SideEffects ComputeChanges(HInstruction* instr); |
| 89 SideEffects ComputeDependsOn(HInstruction* instr); |
| 90 void PrintSideEffectsTo(StringStream* stream, SideEffects side_effects) const; |
| 91 |
| 92 private: |
| 93 bool ComputeInobjectField(HObjectAccess access, int* index); |
| 94 |
| 95 HObjectAccess inobject_fields_[SideEffects::kNumberOfSpecials]; |
| 96 int num_inobject_fields_; |
| 97 }; |
| 98 |
| 99 |
39 // Perform common subexpression elimination and loop-invariant code motion. | 100 // Perform common subexpression elimination and loop-invariant code motion. |
40 class HGlobalValueNumberingPhase : public HPhase { | 101 class HGlobalValueNumberingPhase V8_FINAL : public HPhase { |
41 public: | 102 public: |
42 explicit HGlobalValueNumberingPhase(HGraph* graph); | 103 explicit HGlobalValueNumberingPhase(HGraph* graph); |
43 | 104 |
44 void Run(); | 105 void Run(); |
45 | 106 |
46 private: | 107 private: |
47 GVNFlagSet CollectSideEffectsOnPathsToDominatedBlock( | 108 SideEffects CollectSideEffectsOnPathsToDominatedBlock( |
48 HBasicBlock* dominator, | 109 HBasicBlock* dominator, |
49 HBasicBlock* dominated); | 110 HBasicBlock* dominated); |
50 void AnalyzeGraph(); | 111 void AnalyzeGraph(); |
51 void ComputeBlockSideEffects(); | 112 void ComputeBlockSideEffects(); |
52 void LoopInvariantCodeMotion(); | 113 void LoopInvariantCodeMotion(); |
53 void ProcessLoopBlock(HBasicBlock* block, | 114 void ProcessLoopBlock(HBasicBlock* block, |
54 HBasicBlock* before_loop, | 115 HBasicBlock* before_loop, |
55 GVNFlagSet loop_kills); | 116 SideEffects loop_kills); |
56 bool AllowCodeMotion(); | 117 bool AllowCodeMotion(); |
57 bool ShouldMove(HInstruction* instr, HBasicBlock* loop_header); | 118 bool ShouldMove(HInstruction* instr, HBasicBlock* loop_header); |
58 | 119 |
| 120 SideEffectsTracker side_effects_tracker_; |
59 bool removed_side_effects_; | 121 bool removed_side_effects_; |
60 | 122 |
61 // A map of block IDs to their side effects. | 123 // A map of block IDs to their side effects. |
62 ZoneList<GVNFlagSet> block_side_effects_; | 124 ZoneList<SideEffects> block_side_effects_; |
63 | 125 |
64 // A map of loop header block IDs to their loop's side effects. | 126 // A map of loop header block IDs to their loop's side effects. |
65 ZoneList<GVNFlagSet> loop_side_effects_; | 127 ZoneList<SideEffects> loop_side_effects_; |
66 | 128 |
67 // Used when collecting side effects on paths from dominator to | 129 // Used when collecting side effects on paths from dominator to |
68 // dominated. | 130 // dominated. |
69 BitVector visited_on_paths_; | 131 BitVector visited_on_paths_; |
70 | 132 |
71 DISALLOW_COPY_AND_ASSIGN(HGlobalValueNumberingPhase); | 133 DISALLOW_COPY_AND_ASSIGN(HGlobalValueNumberingPhase); |
72 }; | 134 }; |
73 | 135 |
74 | |
75 } } // namespace v8::internal | 136 } } // namespace v8::internal |
76 | 137 |
77 #endif // V8_HYDROGEN_GVN_H_ | 138 #endif // V8_HYDROGEN_GVN_H_ |
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