-
Notifications
You must be signed in to change notification settings - Fork 22
/
pass_stack_liveness.go
135 lines (112 loc) · 3.66 KB
/
pass_stack_liveness.go
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
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
/*
* Copyright 2022 ByteDance Inc.
*
* 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.
*/
package ssa
import (
`fmt`
)
// StackLiveness calculates the liveness of each stack slot.
type StackLiveness struct{}
func (self StackLiveness) livein(lr map[Pos]SlotSet, bb *BasicBlock, in map[int]SlotSet, out map[int]SlotSet) SlotSet {
var ok bool
var ss SlotSet
var sp *IrSpill
/* check for cached live-in sets */
if ss, ok = in[bb.Id]; ok {
return ss.clone()
}
/* calculate the live-out set of current block */
tr := bb.Term
sl := self.liveout(lr, bb, in, out).clone()
/* assume all terminators are non-definitive */
if _, ok = tr.(IrDefinitions); ok {
panic("regalloc: definitions within terminators")
}
/* mark live range of the terminator */
rr := sl.clone()
lr[pos(bb, _P_term)] = rr
/* live(i-1) = use(i) ∪ (live(i) - { def(i) }) */
for i := len(bb.Ins) - 1; i >= 0; i-- {
ins := bb.Ins[i]
sp, ok = ins.(*IrSpill)
/* only account for pointer slots */
if !ok || !sp.S.IsPtr() {
lr[pos(bb, i)] = sl.clone()
continue
}
/* handle spill operations */
switch sp.Op {
default: {
panic("stackmap: invalid spill Op")
}
/* store operaion marks the value is alive since here */
case IrSpillStore: {
if sl.remove(sp.S) {
lr[pos(bb, i)] = sl.clone()
} else {
panic(fmt.Sprintf("stackmap: killing non-existing value %s at %s:%d. ins = %s", sp.S, bb, i, bb.Ins[i]))
}
}
/* load operaion marks the value is alive until here */
case IrSpillReload: {
if sl.add(sp.S) {
lr[pos(bb, i)] = sl.clone()
}
}
}
}
/* should not have any Phi nodes */
if len(bb.Phi) != 0 {
panic("regalloc: unexpected Phi nodes")
}
/* update the cache */
in[bb.Id] = sl.clone()
return sl
}
func (self StackLiveness) liveout(lr map[Pos]SlotSet, bb *BasicBlock, in map[int]SlotSet, out map[int]SlotSet) SlotSet {
var ok bool
var ss SlotSet
var it IrSuccessors
/* check for cached live-out sets */
if ss, ok = out[bb.Id]; ok {
return ss
}
/* check for return blocks */
if _, ok = IrTryIntoArchReturn(bb.Term); ok {
out[bb.Id] = make(SlotSet)
return ss
}
/* create a new register set */
ss = make(SlotSet)
it = bb.Term.Successors()
/* live-out(p) = ∑(live-in(succ(p))) */
for out[bb.Id] = nil; it.Next(); {
for sl := range self.livein(lr, it.Block(), in, out) {
ss.add(sl)
}
}
/* update cache */
out[bb.Id] = ss
return ss
}
func (self StackLiveness) liveness(cfg *CFG) {
for ss := range self.livein(cfg.Func.Liveness, cfg.Root, make(map[int]SlotSet), make(map[int]SlotSet)) {
panic("stackliveness: live slot at entry: " + ss.String())
}
}
func (self StackLiveness) Apply(cfg *CFG) {
cfg.Func.Liveness = make(map[Pos]SlotSet)
self.liveness(cfg)
}