blob: 53fa74ee2716d8f287cbc09fce20b7d8e890dc56 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "ssa_type_propagation.h"
#include "nodes.h"
namespace art {
static Primitive::Type MergeTypes(Primitive::Type existing, Primitive::Type new_type) {
// We trust the verifier has already done the necessary checking.
switch (existing) {
case Primitive::kPrimFloat:
case Primitive::kPrimDouble:
case Primitive::kPrimNot:
return existing;
default:
return new_type;
}
}
// Re-compute and update the type of the instruction. Returns
// whether or not the type was changed.
static bool UpdateType(HPhi* phi) {
Primitive::Type existing = phi->GetType();
Primitive::Type new_type = Primitive::kPrimVoid;
for (size_t i = 0, e = phi->InputCount(); i < e; ++i) {
Primitive::Type input_type = phi->InputAt(i)->GetType();
new_type = MergeTypes(new_type, input_type);
}
phi->SetType(new_type);
return existing != new_type;
}
void SsaTypePropagation::Run() {
for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) {
VisitBasicBlock(it.Current());
}
ProcessWorklist();
}
void SsaTypePropagation::VisitBasicBlock(HBasicBlock* block) {
if (block->IsLoopHeader()) {
for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
HPhi* phi = it.Current()->AsPhi();
// Set the initial type for the phi. Use the non back edge input for reaching
// a fixed point faster.
phi->SetType(phi->InputAt(0)->GetType());
AddToWorklist(phi);
}
} else {
for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
HPhi* phi = it.Current()->AsPhi();
if (UpdateType(phi)) {
AddDependentInstructionsToWorklist(phi);
}
}
}
}
void SsaTypePropagation::ProcessWorklist() {
while (!worklist_.IsEmpty()) {
HPhi* instruction = worklist_.Pop();
if (UpdateType(instruction)) {
AddDependentInstructionsToWorklist(instruction);
}
}
}
void SsaTypePropagation::AddToWorklist(HPhi* instruction) {
worklist_.Add(instruction);
}
void SsaTypePropagation::AddDependentInstructionsToWorklist(HPhi* instruction) {
for (HUseIterator<HInstruction> it(instruction->GetUses()); !it.Done(); it.Advance()) {
HPhi* phi = it.Current()->GetUser()->AsPhi();
if (phi != nullptr) {
AddToWorklist(phi);
}
}
}
} // namespace art
|
