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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/compiler/tail-call-optimization.h" | 5 #include "src/compiler/tail-call-optimization.h" |
6 | 6 |
7 #include "src/compiler/common-operator.h" | 7 #include "src/compiler/common-operator.h" |
8 #include "src/compiler/graph.h" | 8 #include "src/compiler/graph.h" |
9 #include "src/compiler/linkage.h" | 9 #include "src/compiler/linkage.h" |
10 #include "src/compiler/node-matchers.h" | |
11 #include "src/compiler/node-properties.h" | 10 #include "src/compiler/node-properties.h" |
12 | 11 |
13 namespace v8 { | 12 namespace v8 { |
14 namespace internal { | 13 namespace internal { |
15 namespace compiler { | 14 namespace compiler { |
16 | 15 |
17 Reduction TailCallOptimization::Reduce(Node* node) { | 16 Reduction TailCallOptimization::Reduce(Node* node) { |
18 if (node->opcode() != IrOpcode::kReturn) return NoChange(); | 17 if (node->opcode() != IrOpcode::kReturn) return NoChange(); |
19 // The value which is returned must be the result of a potential tail call, | 18 // The value which is returned must be the result of a potential tail call, |
20 // there must be no try/catch/finally around the Call, and there must be no | 19 // there must be no try/catch/finally around the Call, and there must be no |
21 // other effect between the Call and the Return nodes. | 20 // other effect between the Call and the Return nodes. |
22 Node* const call = NodeProperties::GetValueInput(node, 1); | 21 Node* const call = NodeProperties::GetValueInput(node, 0); |
23 if (call->opcode() == IrOpcode::kCall && | 22 if (call->opcode() == IrOpcode::kCall && |
24 CallDescriptorOf(call->op())->SupportsTailCalls() && | 23 CallDescriptorOf(call->op())->SupportsTailCalls() && |
25 NodeProperties::GetEffectInput(node) == call && | 24 NodeProperties::GetEffectInput(node) == call && |
26 !NodeProperties::IsExceptionalCall(call)) { | 25 !NodeProperties::IsExceptionalCall(call)) { |
27 Node* const control = NodeProperties::GetControlInput(node); | 26 Node* const control = NodeProperties::GetControlInput(node); |
28 // Ensure that no additional arguments are being popped other than those in | |
29 // the CallDescriptor, otherwise the tail call transformation is invalid. | |
30 DCHECK_EQ(0, Int32Matcher(NodeProperties::GetValueInput(node, 0)).Value()); | |
31 if (control->opcode() == IrOpcode::kIfSuccess && | 27 if (control->opcode() == IrOpcode::kIfSuccess && |
32 call->OwnedBy(node, control) && control->OwnedBy(node)) { | 28 call->OwnedBy(node, control) && control->OwnedBy(node)) { |
33 // Furthermore, control has to flow via an IfSuccess from the Call, so | 29 // Furthermore, control has to flow via an IfSuccess from the Call, so |
34 // the Return node value and effect depends directly on the Call node, | 30 // the Return node value and effect depends directly on the Call node, |
35 // and indirectly control depends on the Call via an IfSuccess. | 31 // and indirectly control depends on the Call via an IfSuccess. |
36 | 32 |
37 // Value1 ... ValueN Effect Control | 33 // Value1 ... ValueN Effect Control |
38 // ^ ^ ^ ^ | 34 // ^ ^ ^ ^ |
39 // | | | | | 35 // | | | | |
40 // | +--+ +-+ | | 36 // | +--+ +-+ | |
(...skipping 18 matching lines...) Expand all Loading... |
59 // ^ ^ ^ ^ | 55 // ^ ^ ^ ^ |
60 // | | | | | 56 // | | | | |
61 // | +--+ +-+ | | 57 // | +--+ +-+ | |
62 // +----------+ | | +------+ | 58 // +----------+ | | +------+ |
63 // \ | | / | 59 // \ | | / |
64 // TailCall[Descriptor] | 60 // TailCall[Descriptor] |
65 // ^ | 61 // ^ |
66 // | | 62 // | |
67 | 63 |
68 DCHECK_EQ(call, NodeProperties::GetControlInput(control, 0)); | 64 DCHECK_EQ(call, NodeProperties::GetControlInput(control, 0)); |
69 DCHECK_EQ(4, node->InputCount()); | 65 DCHECK_EQ(3, node->InputCount()); |
70 node->ReplaceInput(0, NodeProperties::GetEffectInput(call)); | 66 node->ReplaceInput(0, NodeProperties::GetEffectInput(call)); |
71 node->ReplaceInput(1, NodeProperties::GetControlInput(call)); | 67 node->ReplaceInput(1, NodeProperties::GetControlInput(call)); |
72 node->RemoveInput(3); | |
73 node->RemoveInput(2); | 68 node->RemoveInput(2); |
74 for (int index = 0; index < call->op()->ValueInputCount(); ++index) { | 69 for (int index = 0; index < call->op()->ValueInputCount(); ++index) { |
75 node->InsertInput(graph()->zone(), index, | 70 node->InsertInput(graph()->zone(), index, |
76 NodeProperties::GetValueInput(call, index)); | 71 NodeProperties::GetValueInput(call, index)); |
77 } | 72 } |
78 NodeProperties::ChangeOp( | 73 NodeProperties::ChangeOp( |
79 node, common()->TailCall(CallDescriptorOf(call->op()))); | 74 node, common()->TailCall(CallDescriptorOf(call->op()))); |
80 return Changed(node); | 75 return Changed(node); |
81 } | 76 } |
82 } | 77 } |
83 return NoChange(); | 78 return NoChange(); |
84 } | 79 } |
85 | 80 |
86 } // namespace compiler | 81 } // namespace compiler |
87 } // namespace internal | 82 } // namespace internal |
88 } // namespace v8 | 83 } // namespace v8 |
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