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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
|
package gocapturedrefrace
import (
"fmt"
"go/ast"
"go/token"
"go/types"
"golang.org/x/tools/go/analysis"
)
var Analyzer = &analysis.Analyzer{
Name: "gocapturedrefrace",
Doc: "reports captured references in goroutine closures",
Run: run,
}
func run(pass *analysis.Pass) (interface{}, error) {
for _, file := range pass.Files {
ast.Inspect(
file,
func(node ast.Node) bool {
// Find `go` statements.
goStmt, ok := node.(*ast.GoStmt)
if !ok {
return true
}
// Look for a function literal after the `go` statement.
funcLit, ok := goStmt.Call.Fun.(*ast.FuncLit)
if !ok {
return true
}
// Inspect closure argument list.
for _, arg := range funcLit.Type.Params.List {
// Report reference arguments.
_, ok := arg.Type.(*ast.StarExpr)
if !ok {
continue
}
pass.Reportf(
arg.Pos(),
"reference %s in goroutine closure",
arg.Names[0],
)
}
// Get the closure's scope.
funcScope := pass.TypesInfo.Scopes[funcLit.Type]
checkClosure(pass, funcLit, funcScope)
return true
},
)
}
return nil, nil
}
func checkClosure(
pass *analysis.Pass,
funcLit *ast.FuncLit,
funcScope *types.Scope,
) {
formalParams := []*ast.Object{}
for _, field := range funcLit.Type.Params.List {
formalParams = append(formalParams, field.Names[0].Obj)
}
fmt.Printf("formalParams: %#v\n", formalParams)
// TODO: Ensure argument types are not references
// TODO: goStmt.Call.Args should also give us something like this.
// TODO: Build a list of variables created in the closure
// assignments := assignmentsInFunc(pass, funcLit)
// fmt.Printf("variable declarations: %#v\n", assignments)
// TODO: Use ast.GenDecl instead
// ast.Scope?
// TODO: Need to find variables not declared in the closure, and
// reference arguments
ast.Inspect(
funcLit,
func(node ast.Node) bool {
ident, ok := node.(*ast.Ident)
if !ok {
return true
}
if ident.Obj == nil {
return true
}
// TODO: Find out whether ident is a captured reference
// Maybe check if variable was not assigned or passed as an argument?
// for _, param := range formalParams {
// if ident.Obj == param {
// return true
// }
// }
// TODO: Use (*types.Scope).LookupParent with ident to find out
// whether a variable was defined in an outer scope.
scope, scopeObj := funcScope.LookupParent(ident.Name, ident.NamePos)
fmt.Println("LookupParent:")
fmt.Printf(" scope: %#v\n", scope)
fmt.Printf(" obj : %#v\n", scopeObj)
// If scope and scopeObj are nil, then variable is local
// This also means variable is local.
if funcScope == scope {
fmt.Printf("In function scope %v\n", scopeObj)
}
// Identifier is local to the closure.
if scope == nil && scopeObj == nil {
return true
}
_, ok = scopeObj.(*types.Var)
if !ok {
return true
}
if funcScope != scope {
pass.Reportf(
ident.Pos(),
"captured reference %s in goroutine closure",
ident,
)
}
// TODO: Report references in argument list
return true
},
)
}
func assignmentsInFunc(
pass *analysis.Pass,
funcLit *ast.FuncLit,
) []string {
assignments := []string{}
// ) []*ast.Object {
// assignments := []*ast.Object{}
ast.Inspect(
funcLit,
func(node ast.Node) bool {
// decl, ok := node.(*ast.GenDecl)
// if !ok {
// return true
// }
//
// fmt.Printf("decl: %#v\n", decl)
//
// if decl.Tok != token.VAR {
// return true
// }
//
// for _, spec := range decl.Specs {
// valueSpec, ok := spec.(*ast.ValueSpec)
// if !ok {
// return true
// }
//
// fmt.Printf("valueSpec: %#v\n", valueSpec)
//
// assignments = append(assignments, valueSpec.Names[0].Obj)
// }
// decl, ok := node.(*ast.DeclStmt)
// if !ok {
// return true
// }
//
// fmt.Printf("decl: %#v\n", decl)
ident, ok := node.(*ast.Ident)
if !ok {
return true
}
if ident.Obj == nil || ident.Obj.Decl == nil {
return true
}
assignment, ok := ident.Obj.Decl.(*ast.AssignStmt)
if !ok {
return true
}
// fmt.Printf("assignment: %#v\n", assignment.Tok)
if assignment.Tok == token.DEFINE {
fmt.Printf("assignment: %v is DEFINE\n", ident.Name)
} else if assignment.Tok == token.ASSIGN {
fmt.Printf("assignment: %v is ASSIGN\n", ident.Name)
} else {
fmt.Printf("assignment: %v\n", assignment.Tok)
}
if pass.TypesInfo.Defs[ident] != nil {
fmt.Println("DEFINE:", ident)
} else {
fmt.Println("ASSIGN:", ident)
}
obj := pass.TypesInfo.ObjectOf(ident)
if obj != nil {
fmt.Printf("obj: %#v\n", obj)
theVar, ok := obj.(*types.Var)
if !ok {
return true
}
fmt.Printf("obj origin: %#v\n", theVar.Origin())
fmt.Printf("obj parent: %#v\n", theVar.Parent())
}
assignments = append(assignments, ident.Name)
return true
},
)
return assignments
}
|
