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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 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef V8_HYDROGEN_GVN_H_ | 5 #ifndef V8_HYDROGEN_GVN_H_ |
6 #define V8_HYDROGEN_GVN_H_ | 6 #define V8_HYDROGEN_GVN_H_ |
7 | 7 |
| 8 #include "src/compiler.h" |
8 #include "src/hydrogen.h" | 9 #include "src/hydrogen.h" |
9 #include "src/hydrogen-instructions.h" | 10 #include "src/hydrogen-instructions.h" |
10 #include "src/compiler.h" | 11 #include "src/ostreams.h" |
11 #include "src/zone.h" | 12 #include "src/zone.h" |
12 | 13 |
13 namespace v8 { | 14 namespace v8 { |
14 namespace internal { | 15 namespace internal { |
15 | 16 |
16 // This class extends GVNFlagSet with additional "special" dynamic side effects, | 17 // This class extends GVNFlagSet with additional "special" dynamic side effects, |
17 // which can be used to represent side effects that cannot be expressed using | 18 // which can be used to represent side effects that cannot be expressed using |
18 // the GVNFlags of an HInstruction. These special side effects are tracked by a | 19 // the GVNFlags of an HInstruction. These special side effects are tracked by a |
19 // SideEffectsTracker (see below). | 20 // SideEffectsTracker (see below). |
20 class SideEffects V8_FINAL { | 21 class SideEffects V8_FINAL { |
(...skipping 10 matching lines...) Expand all Loading... |
31 } | 32 } |
32 bool ContainsSpecial(int special) const { | 33 bool ContainsSpecial(int special) const { |
33 return (bits_ & MaskSpecial(special)) != 0; | 34 return (bits_ & MaskSpecial(special)) != 0; |
34 } | 35 } |
35 bool ContainsAnyOf(SideEffects set) const { return (bits_ & set.bits_) != 0; } | 36 bool ContainsAnyOf(SideEffects set) const { return (bits_ & set.bits_) != 0; } |
36 void Add(SideEffects set) { bits_ |= set.bits_; } | 37 void Add(SideEffects set) { bits_ |= set.bits_; } |
37 void AddSpecial(int special) { bits_ |= MaskSpecial(special); } | 38 void AddSpecial(int special) { bits_ |= MaskSpecial(special); } |
38 void RemoveFlag(GVNFlag flag) { bits_ &= ~MaskFlag(flag); } | 39 void RemoveFlag(GVNFlag flag) { bits_ &= ~MaskFlag(flag); } |
39 void RemoveAll() { bits_ = 0; } | 40 void RemoveAll() { bits_ = 0; } |
40 uint64_t ToIntegral() const { return bits_; } | 41 uint64_t ToIntegral() const { return bits_; } |
41 void PrintTo(StringStream* stream) const; | |
42 | 42 |
43 private: | 43 private: |
44 uint64_t MaskFlag(GVNFlag flag) const { | 44 uint64_t MaskFlag(GVNFlag flag) const { |
45 return static_cast<uint64_t>(1) << static_cast<unsigned>(flag); | 45 return static_cast<uint64_t>(1) << static_cast<unsigned>(flag); |
46 } | 46 } |
47 uint64_t MaskSpecial(int special) const { | 47 uint64_t MaskSpecial(int special) const { |
48 ASSERT(special >= 0); | 48 ASSERT(special >= 0); |
49 ASSERT(special < kNumberOfSpecials); | 49 ASSERT(special < kNumberOfSpecials); |
50 return static_cast<uint64_t>(1) << static_cast<unsigned>( | 50 return static_cast<uint64_t>(1) << static_cast<unsigned>( |
51 special + kNumberOfFlags); | 51 special + kNumberOfFlags); |
52 } | 52 } |
53 | 53 |
54 uint64_t bits_; | 54 uint64_t bits_; |
55 }; | 55 }; |
56 | 56 |
57 | 57 |
| 58 class TrackedEffects; |
| 59 |
58 // Tracks global variable and inobject field loads/stores in a fine grained | 60 // Tracks global variable and inobject field loads/stores in a fine grained |
59 // fashion, and represents them using the "special" dynamic side effects of the | 61 // fashion, and represents them using the "special" dynamic side effects of the |
60 // SideEffects class (see above). This way unrelated global variable/inobject | 62 // SideEffects class (see above). This way unrelated global variable/inobject |
61 // field stores don't prevent hoisting and merging of global variable/inobject | 63 // field stores don't prevent hoisting and merging of global variable/inobject |
62 // field loads. | 64 // field loads. |
63 class SideEffectsTracker V8_FINAL BASE_EMBEDDED { | 65 class SideEffectsTracker V8_FINAL BASE_EMBEDDED { |
64 public: | 66 public: |
65 SideEffectsTracker() : num_global_vars_(0), num_inobject_fields_(0) {} | 67 SideEffectsTracker() : num_global_vars_(0), num_inobject_fields_(0) {} |
66 SideEffects ComputeChanges(HInstruction* instr); | 68 SideEffects ComputeChanges(HInstruction* instr); |
67 SideEffects ComputeDependsOn(HInstruction* instr); | 69 SideEffects ComputeDependsOn(HInstruction* instr); |
68 void PrintSideEffectsTo(StringStream* stream, SideEffects side_effects) const; | |
69 | 70 |
70 private: | 71 private: |
| 72 friend OStream& operator<<(OStream& os, const TrackedEffects& f); |
71 bool ComputeGlobalVar(Unique<Cell> cell, int* index); | 73 bool ComputeGlobalVar(Unique<Cell> cell, int* index); |
72 bool ComputeInobjectField(HObjectAccess access, int* index); | 74 bool ComputeInobjectField(HObjectAccess access, int* index); |
73 | 75 |
74 static int GlobalVar(int index) { | 76 static int GlobalVar(int index) { |
75 ASSERT(index >= 0); | 77 ASSERT(index >= 0); |
76 ASSERT(index < kNumberOfGlobalVars); | 78 ASSERT(index < kNumberOfGlobalVars); |
77 return index; | 79 return index; |
78 } | 80 } |
79 static int InobjectField(int index) { | 81 static int InobjectField(int index) { |
80 ASSERT(index >= 0); | 82 ASSERT(index >= 0); |
81 ASSERT(index < kNumberOfInobjectFields); | 83 ASSERT(index < kNumberOfInobjectFields); |
82 return index + kNumberOfGlobalVars; | 84 return index + kNumberOfGlobalVars; |
83 } | 85 } |
84 | 86 |
85 // Track up to four global vars. | 87 // Track up to four global vars. |
86 static const int kNumberOfGlobalVars = 4; | 88 static const int kNumberOfGlobalVars = 4; |
87 Unique<Cell> global_vars_[kNumberOfGlobalVars]; | 89 Unique<Cell> global_vars_[kNumberOfGlobalVars]; |
88 int num_global_vars_; | 90 int num_global_vars_; |
89 | 91 |
90 // Track up to n inobject fields. | 92 // Track up to n inobject fields. |
91 static const int kNumberOfInobjectFields = | 93 static const int kNumberOfInobjectFields = |
92 SideEffects::kNumberOfSpecials - kNumberOfGlobalVars; | 94 SideEffects::kNumberOfSpecials - kNumberOfGlobalVars; |
93 HObjectAccess inobject_fields_[kNumberOfInobjectFields]; | 95 HObjectAccess inobject_fields_[kNumberOfInobjectFields]; |
94 int num_inobject_fields_; | 96 int num_inobject_fields_; |
95 }; | 97 }; |
96 | 98 |
97 | 99 |
| 100 // Helper class for printing, because the effects don't know their tracker. |
| 101 struct TrackedEffects { |
| 102 TrackedEffects(SideEffectsTracker* t, SideEffects e) |
| 103 : tracker(t), effects(e) {} |
| 104 SideEffectsTracker* tracker; |
| 105 SideEffects effects; |
| 106 }; |
| 107 |
| 108 |
| 109 OStream& operator<<(OStream& os, const TrackedEffects& f); |
| 110 |
| 111 |
98 // Perform common subexpression elimination and loop-invariant code motion. | 112 // Perform common subexpression elimination and loop-invariant code motion. |
99 class HGlobalValueNumberingPhase V8_FINAL : public HPhase { | 113 class HGlobalValueNumberingPhase V8_FINAL : public HPhase { |
100 public: | 114 public: |
101 explicit HGlobalValueNumberingPhase(HGraph* graph); | 115 explicit HGlobalValueNumberingPhase(HGraph* graph); |
102 | 116 |
103 void Run(); | 117 void Run(); |
104 | 118 |
105 private: | 119 private: |
106 SideEffects CollectSideEffectsOnPathsToDominatedBlock( | 120 SideEffects CollectSideEffectsOnPathsToDominatedBlock( |
107 HBasicBlock* dominator, | 121 HBasicBlock* dominator, |
108 HBasicBlock* dominated); | 122 HBasicBlock* dominated); |
109 void AnalyzeGraph(); | 123 void AnalyzeGraph(); |
110 void ComputeBlockSideEffects(); | 124 void ComputeBlockSideEffects(); |
111 void LoopInvariantCodeMotion(); | 125 void LoopInvariantCodeMotion(); |
112 void ProcessLoopBlock(HBasicBlock* block, | 126 void ProcessLoopBlock(HBasicBlock* block, |
113 HBasicBlock* before_loop, | 127 HBasicBlock* before_loop, |
114 SideEffects loop_kills); | 128 SideEffects loop_kills); |
115 bool AllowCodeMotion(); | 129 bool AllowCodeMotion(); |
116 bool ShouldMove(HInstruction* instr, HBasicBlock* loop_header); | 130 bool ShouldMove(HInstruction* instr, HBasicBlock* loop_header); |
| 131 TrackedEffects Print(SideEffects side_effects) { |
| 132 return TrackedEffects(&side_effects_tracker_, side_effects); |
| 133 } |
117 | 134 |
118 SideEffectsTracker side_effects_tracker_; | 135 SideEffectsTracker side_effects_tracker_; |
119 bool removed_side_effects_; | 136 bool removed_side_effects_; |
120 | 137 |
121 // A map of block IDs to their side effects. | 138 // A map of block IDs to their side effects. |
122 ZoneList<SideEffects> block_side_effects_; | 139 ZoneList<SideEffects> block_side_effects_; |
123 | 140 |
124 // A map of loop header block IDs to their loop's side effects. | 141 // A map of loop header block IDs to their loop's side effects. |
125 ZoneList<SideEffects> loop_side_effects_; | 142 ZoneList<SideEffects> loop_side_effects_; |
126 | 143 |
127 // Used when collecting side effects on paths from dominator to | 144 // Used when collecting side effects on paths from dominator to |
128 // dominated. | 145 // dominated. |
129 BitVector visited_on_paths_; | 146 BitVector visited_on_paths_; |
130 | 147 |
131 DISALLOW_COPY_AND_ASSIGN(HGlobalValueNumberingPhase); | 148 DISALLOW_COPY_AND_ASSIGN(HGlobalValueNumberingPhase); |
132 }; | 149 }; |
133 | 150 |
134 } } // namespace v8::internal | 151 } } // namespace v8::internal |
135 | 152 |
136 #endif // V8_HYDROGEN_GVN_H_ | 153 #endif // V8_HYDROGEN_GVN_H_ |
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