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
136
|
// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package dwarfgen
import (
"sort"
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
"cmd/internal/dwarf"
"cmd/internal/obj"
"cmd/internal/src"
)
// See golang.org/issue/20390.
func xposBefore(p, q src.XPos) bool {
return base.Ctxt.PosTable.Pos(p).Before(base.Ctxt.PosTable.Pos(q))
}
func findScope(marks []ir.Mark, pos src.XPos) ir.ScopeID {
i := sort.Search(len(marks), func(i int) bool {
return xposBefore(pos, marks[i].Pos)
})
if i == 0 {
return 0
}
return marks[i-1].Scope
}
func assembleScopes(fnsym *obj.LSym, fn *ir.Func, dwarfVars []*dwarf.Var, varScopes []ir.ScopeID) []dwarf.Scope {
// Initialize the DWARF scope tree based on lexical scopes.
dwarfScopes := make([]dwarf.Scope, 1+len(fn.Parents))
for i, parent := range fn.Parents {
dwarfScopes[i+1].Parent = int32(parent)
}
scopeVariables(dwarfVars, varScopes, dwarfScopes, fnsym.ABI() != obj.ABI0)
if fnsym.Func().Text != nil {
scopePCs(fnsym, fn.Marks, dwarfScopes)
}
return compactScopes(dwarfScopes)
}
// scopeVariables assigns DWARF variable records to their scopes.
func scopeVariables(dwarfVars []*dwarf.Var, varScopes []ir.ScopeID, dwarfScopes []dwarf.Scope, regabi bool) {
if regabi {
sort.Stable(varsByScope{dwarfVars, varScopes})
} else {
sort.Stable(varsByScopeAndOffset{dwarfVars, varScopes})
}
i0 := 0
for i := range dwarfVars {
if varScopes[i] == varScopes[i0] {
continue
}
dwarfScopes[varScopes[i0]].Vars = dwarfVars[i0:i]
i0 = i
}
if i0 < len(dwarfVars) {
dwarfScopes[varScopes[i0]].Vars = dwarfVars[i0:]
}
}
// scopePCs assigns PC ranges to their scopes.
func scopePCs(fnsym *obj.LSym, marks []ir.Mark, dwarfScopes []dwarf.Scope) {
// If there aren't any child scopes (in particular, when scope
// tracking is disabled), we can skip a whole lot of work.
if len(marks) == 0 {
return
}
p0 := fnsym.Func().Text
scope := findScope(marks, p0.Pos)
for p := p0; p != nil; p = p.Link {
if p.Pos == p0.Pos {
continue
}
dwarfScopes[scope].AppendRange(dwarf.Range{Start: p0.Pc, End: p.Pc})
p0 = p
scope = findScope(marks, p0.Pos)
}
if p0.Pc < fnsym.Size {
dwarfScopes[scope].AppendRange(dwarf.Range{Start: p0.Pc, End: fnsym.Size})
}
}
func compactScopes(dwarfScopes []dwarf.Scope) []dwarf.Scope {
// Reverse pass to propagate PC ranges to parent scopes.
for i := len(dwarfScopes) - 1; i > 0; i-- {
s := &dwarfScopes[i]
dwarfScopes[s.Parent].UnifyRanges(s)
}
return dwarfScopes
}
type varsByScopeAndOffset struct {
vars []*dwarf.Var
scopes []ir.ScopeID
}
func (v varsByScopeAndOffset) Len() int {
return len(v.vars)
}
func (v varsByScopeAndOffset) Less(i, j int) bool {
if v.scopes[i] != v.scopes[j] {
return v.scopes[i] < v.scopes[j]
}
return v.vars[i].StackOffset < v.vars[j].StackOffset
}
func (v varsByScopeAndOffset) Swap(i, j int) {
v.vars[i], v.vars[j] = v.vars[j], v.vars[i]
v.scopes[i], v.scopes[j] = v.scopes[j], v.scopes[i]
}
type varsByScope struct {
vars []*dwarf.Var
scopes []ir.ScopeID
}
func (v varsByScope) Len() int {
return len(v.vars)
}
func (v varsByScope) Less(i, j int) bool {
return v.scopes[i] < v.scopes[j]
}
func (v varsByScope) Swap(i, j int) {
v.vars[i], v.vars[j] = v.vars[j], v.vars[i]
v.scopes[i], v.scopes[j] = v.scopes[j], v.scopes[i]
}
|
