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1 // Copyright 2015 the V8 project authors. All rights reserved. | 1 // Copyright 2015 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 #include "src/base/adapters.h" | 5 #include "src/base/adapters.h" |
6 #include "src/compiler/frame-elider.h" | 6 #include "src/compiler/frame-elider.h" |
7 | 7 |
8 namespace v8 { | 8 namespace v8 { |
9 namespace internal { | 9 namespace internal { |
10 namespace compiler { | 10 namespace compiler { |
11 | 11 |
12 FrameElider::FrameElider(InstructionSequence* code) : code_(code) {} | 12 FrameElider::FrameElider(InstructionSequence* code) : code_(code) {} |
13 | 13 |
14 void FrameElider::Run() { | 14 void FrameElider::Run() { |
15 MarkBlocks(); | 15 MarkBlocks(); |
16 PropagateMarks(); | 16 PropagateMarks(); |
17 MarkDeConstruction(); | 17 MarkDeConstruction(); |
18 } | 18 } |
19 | 19 |
20 | 20 |
21 void FrameElider::MarkBlocks() { | 21 void FrameElider::MarkBlocks() { |
22 for (auto block : instruction_blocks()) { | 22 for (InstructionBlock* block : instruction_blocks()) { |
23 if (block->needs_frame()) continue; | 23 if (block->needs_frame()) continue; |
24 for (auto i = block->code_start(); i < block->code_end(); ++i) { | 24 for (int i = block->code_start(); i < block->code_end(); ++i) { |
25 if (InstructionAt(i)->IsCall() || | 25 if (InstructionAt(i)->IsCall() || |
26 InstructionAt(i)->opcode() == ArchOpcode::kArchDeoptimize) { | 26 InstructionAt(i)->opcode() == ArchOpcode::kArchDeoptimize) { |
27 block->mark_needs_frame(); | 27 block->mark_needs_frame(); |
28 break; | 28 break; |
29 } | 29 } |
30 } | 30 } |
31 } | 31 } |
32 } | 32 } |
33 | 33 |
34 | 34 |
35 void FrameElider::PropagateMarks() { | 35 void FrameElider::PropagateMarks() { |
36 while (PropagateInOrder() && PropagateReversed()) { | 36 while (PropagateInOrder() && PropagateReversed()) { |
37 } | 37 } |
38 } | 38 } |
39 | 39 |
40 | 40 |
41 void FrameElider::MarkDeConstruction() { | 41 void FrameElider::MarkDeConstruction() { |
42 for (auto block : instruction_blocks()) { | 42 for (InstructionBlock* block : instruction_blocks()) { |
43 if (block->needs_frame()) { | 43 if (block->needs_frame()) { |
44 // Special case: The start block needs a frame. | 44 // Special case: The start block needs a frame. |
45 if (block->predecessors().empty()) { | 45 if (block->predecessors().empty()) { |
46 block->mark_must_construct_frame(); | 46 block->mark_must_construct_frame(); |
47 } | 47 } |
48 // Find "frame -> no frame" transitions, inserting frame | 48 // Find "frame -> no frame" transitions, inserting frame |
49 // deconstructions. | 49 // deconstructions. |
50 for (auto succ : block->successors()) { | 50 for (RpoNumber& succ : block->successors()) { |
51 if (!InstructionBlockAt(succ)->needs_frame()) { | 51 if (!InstructionBlockAt(succ)->needs_frame()) { |
52 DCHECK_EQ(1U, block->SuccessorCount()); | 52 DCHECK_EQ(1U, block->SuccessorCount()); |
53 block->mark_must_deconstruct_frame(); | 53 block->mark_must_deconstruct_frame(); |
54 } | 54 } |
55 } | 55 } |
56 } else { | 56 } else { |
57 // Find "no frame -> frame" transitions, inserting frame constructions. | 57 // Find "no frame -> frame" transitions, inserting frame constructions. |
58 for (auto succ : block->successors()) { | 58 for (RpoNumber& succ : block->successors()) { |
59 if (InstructionBlockAt(succ)->needs_frame()) { | 59 if (InstructionBlockAt(succ)->needs_frame()) { |
60 DCHECK_NE(1U, block->SuccessorCount()); | 60 DCHECK_NE(1U, block->SuccessorCount()); |
61 InstructionBlockAt(succ)->mark_must_construct_frame(); | 61 InstructionBlockAt(succ)->mark_must_construct_frame(); |
62 } | 62 } |
63 } | 63 } |
64 } | 64 } |
65 } | 65 } |
66 } | 66 } |
67 | 67 |
68 | 68 |
69 bool FrameElider::PropagateInOrder() { | 69 bool FrameElider::PropagateInOrder() { |
70 bool changed = false; | 70 bool changed = false; |
71 for (auto block : instruction_blocks()) { | 71 for (InstructionBlock* block : instruction_blocks()) { |
72 changed |= PropagateIntoBlock(block); | 72 changed |= PropagateIntoBlock(block); |
73 } | 73 } |
74 return changed; | 74 return changed; |
75 } | 75 } |
76 | 76 |
77 | 77 |
78 bool FrameElider::PropagateReversed() { | 78 bool FrameElider::PropagateReversed() { |
79 bool changed = false; | 79 bool changed = false; |
80 for (auto block : base::Reversed(instruction_blocks())) { | 80 for (InstructionBlock* block : base::Reversed(instruction_blocks())) { |
81 changed |= PropagateIntoBlock(block); | 81 changed |= PropagateIntoBlock(block); |
82 } | 82 } |
83 return changed; | 83 return changed; |
84 } | 84 } |
85 | 85 |
86 | 86 |
87 bool FrameElider::PropagateIntoBlock(InstructionBlock* block) { | 87 bool FrameElider::PropagateIntoBlock(InstructionBlock* block) { |
88 // Already marked, nothing to do... | 88 // Already marked, nothing to do... |
89 if (block->needs_frame()) return false; | 89 if (block->needs_frame()) return false; |
90 | 90 |
91 // Never mark the dummy end node, otherwise we might incorrectly decide to | 91 // Never mark the dummy end node, otherwise we might incorrectly decide to |
92 // put frame deconstruction code there later, | 92 // put frame deconstruction code there later, |
93 if (block->successors().empty()) return false; | 93 if (block->successors().empty()) return false; |
94 | 94 |
95 // Propagate towards the end ("downwards") if there is a predecessor needing | 95 // Propagate towards the end ("downwards") if there is a predecessor needing |
96 // a frame, but don't "bleed" from deferred code to non-deferred code. | 96 // a frame, but don't "bleed" from deferred code to non-deferred code. |
97 for (auto pred : block->predecessors()) { | 97 for (RpoNumber& pred : block->predecessors()) { |
98 if (InstructionBlockAt(pred)->needs_frame() && | 98 if (InstructionBlockAt(pred)->needs_frame() && |
99 (!InstructionBlockAt(pred)->IsDeferred() || block->IsDeferred())) { | 99 (!InstructionBlockAt(pred)->IsDeferred() || block->IsDeferred())) { |
100 block->mark_needs_frame(); | 100 block->mark_needs_frame(); |
101 return true; | 101 return true; |
102 } | 102 } |
103 } | 103 } |
104 | 104 |
105 // Propagate towards start ("upwards") if there are successors and all of | 105 // Propagate towards start ("upwards") if there are successors and all of |
106 // them need a frame. | 106 // them need a frame. |
107 for (auto succ : block->successors()) { | 107 for (RpoNumber& succ : block->successors()) { |
108 if (!InstructionBlockAt(succ)->needs_frame()) return false; | 108 if (!InstructionBlockAt(succ)->needs_frame()) return false; |
109 } | 109 } |
110 block->mark_needs_frame(); | 110 block->mark_needs_frame(); |
111 return true; | 111 return true; |
112 } | 112 } |
113 | 113 |
114 | 114 |
115 const InstructionBlocks& FrameElider::instruction_blocks() const { | 115 const InstructionBlocks& FrameElider::instruction_blocks() const { |
116 return code_->instruction_blocks(); | 116 return code_->instruction_blocks(); |
117 } | 117 } |
118 | 118 |
119 | 119 |
120 InstructionBlock* FrameElider::InstructionBlockAt(RpoNumber rpo_number) const { | 120 InstructionBlock* FrameElider::InstructionBlockAt(RpoNumber rpo_number) const { |
121 return code_->InstructionBlockAt(rpo_number); | 121 return code_->InstructionBlockAt(rpo_number); |
122 } | 122 } |
123 | 123 |
124 | 124 |
125 Instruction* FrameElider::InstructionAt(int index) const { | 125 Instruction* FrameElider::InstructionAt(int index) const { |
126 return code_->InstructionAt(index); | 126 return code_->InstructionAt(index); |
127 } | 127 } |
128 | 128 |
129 } // namespace compiler | 129 } // namespace compiler |
130 } // namespace internal | 130 } // namespace internal |
131 } // namespace v8 | 131 } // namespace v8 |
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