This repository has been archived by the owner on Apr 28, 2023. It is now read-only.
/
callees.go
257 lines (225 loc) · 6.77 KB
/
callees.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
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
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
// Copyright 2013 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 main
import (
"fmt"
"go/ast"
"go/token"
"go/types"
"sort"
"github.com/Deng-Xian-Sheng/goplus-lsp/cmd/guru/serial"
"github.com/Deng-Xian-Sheng/goplus-lsp/go/loader"
"github.com/Deng-Xian-Sheng/goplus-lsp/go/pointer"
"github.com/Deng-Xian-Sheng/goplus-lsp/go/ssa"
"github.com/Deng-Xian-Sheng/goplus-lsp/go/ssa/ssautil"
)
// The callees function reports the possible callees of the function call site
// identified by the specified source location.
func callees(q *Query) error {
lconf := loader.Config{Build: q.Build}
if err := setPTAScope(&lconf, q.Scope); err != nil {
return err
}
// Load/parse/type-check the program.
lprog, err := loadWithSoftErrors(&lconf)
if err != nil {
return err
}
qpos, err := parseQueryPos(lprog, q.Pos, true) // needs exact pos
if err != nil {
return err
}
// Determine the enclosing call for the specified position.
var e *ast.CallExpr
for _, n := range qpos.path {
if e, _ = n.(*ast.CallExpr); e != nil {
break
}
}
if e == nil {
return fmt.Errorf("there is no function call here")
}
// TODO(adonovan): issue an error if the call is "too far
// away" from the current selection, as this most likely is
// not what the user intended.
// Reject type conversions.
if qpos.info.Types[e.Fun].IsType() {
return fmt.Errorf("this is a type conversion, not a function call")
}
// Deal with obviously static calls before constructing SSA form.
// Some static calls may yet require SSA construction,
// e.g. f := func(){}; f().
switch funexpr := unparen(e.Fun).(type) {
case *ast.Ident:
switch obj := qpos.info.Uses[funexpr].(type) {
case *types.Builtin:
// Reject calls to built-ins.
return fmt.Errorf("this is a call to the built-in '%s' operator", obj.Name())
case *types.Func:
// This is a static function call
q.Output(lprog.Fset, &calleesTypesResult{
site: e,
callee: obj,
})
return nil
}
case *ast.SelectorExpr:
sel := qpos.info.Selections[funexpr]
if sel == nil {
// qualified identifier.
// May refer to top level function variable
// or to top level function.
callee := qpos.info.Uses[funexpr.Sel]
if obj, ok := callee.(*types.Func); ok {
q.Output(lprog.Fset, &calleesTypesResult{
site: e,
callee: obj,
})
return nil
}
} else if sel.Kind() == types.MethodVal {
// Inspect the receiver type of the selected method.
// If it is concrete, the call is statically dispatched.
// (Due to implicit field selections, it is not enough to look
// at sel.Recv(), the type of the actual receiver expression.)
method := sel.Obj().(*types.Func)
recvtype := method.Type().(*types.Signature).Recv().Type()
if !types.IsInterface(recvtype) {
// static method call
q.Output(lprog.Fset, &calleesTypesResult{
site: e,
callee: method,
})
return nil
}
}
}
prog := ssautil.CreateProgram(lprog, ssa.GlobalDebug)
ptaConfig, err := setupPTA(prog, lprog, q.PTALog, q.Reflection)
if err != nil {
return err
}
pkg := prog.Package(qpos.info.Pkg)
if pkg == nil {
return fmt.Errorf("no SSA package")
}
// Defer SSA construction till after errors are reported.
prog.Build()
// Ascertain calling function and call site.
callerFn := ssa.EnclosingFunction(pkg, qpos.path)
if callerFn == nil {
return fmt.Errorf("no SSA function built for this location (dead code?)")
}
// Find the call site.
site, err := findCallSite(callerFn, e)
if err != nil {
return err
}
funcs, err := findCallees(ptaConfig, site)
if err != nil {
return err
}
q.Output(lprog.Fset, &calleesSSAResult{
site: site,
funcs: funcs,
})
return nil
}
func findCallSite(fn *ssa.Function, call *ast.CallExpr) (ssa.CallInstruction, error) {
instr, _ := fn.ValueForExpr(call)
callInstr, _ := instr.(ssa.CallInstruction)
if instr == nil {
return nil, fmt.Errorf("this call site is unreachable in this analysis")
}
return callInstr, nil
}
func findCallees(conf *pointer.Config, site ssa.CallInstruction) ([]*ssa.Function, error) {
// Avoid running the pointer analysis for static calls.
if callee := site.Common().StaticCallee(); callee != nil {
switch callee.String() {
case "runtime.SetFinalizer", "(reflect.Value).Call":
// The PTA treats calls to these intrinsics as dynamic.
// TODO(adonovan): avoid reliance on PTA internals.
default:
return []*ssa.Function{callee}, nil // singleton
}
}
// Dynamic call: use pointer analysis.
conf.BuildCallGraph = true
cg := ptrAnalysis(conf).CallGraph
cg.DeleteSyntheticNodes()
// Find all call edges from the site.
n := cg.Nodes[site.Parent()]
if n == nil {
return nil, fmt.Errorf("this call site is unreachable in this analysis")
}
calleesMap := make(map[*ssa.Function]bool)
for _, edge := range n.Out {
if edge.Site == site {
calleesMap[edge.Callee.Func] = true
}
}
// De-duplicate and sort.
funcs := make([]*ssa.Function, 0, len(calleesMap))
for f := range calleesMap {
funcs = append(funcs, f)
}
sort.Sort(byFuncPos(funcs))
return funcs, nil
}
type calleesSSAResult struct {
site ssa.CallInstruction
funcs []*ssa.Function
}
type calleesTypesResult struct {
site *ast.CallExpr
callee *types.Func
}
func (r *calleesSSAResult) PrintPlain(printf printfFunc) {
if len(r.funcs) == 0 {
// dynamic call on a provably nil func/interface
printf(r.site, "%s on nil value", r.site.Common().Description())
} else {
printf(r.site, "this %s dispatches to:", r.site.Common().Description())
for _, callee := range r.funcs {
printf(callee, "\t%s", callee)
}
}
}
func (r *calleesSSAResult) JSON(fset *token.FileSet) []byte {
j := &serial.Callees{
Pos: fset.Position(r.site.Pos()).String(),
Desc: r.site.Common().Description(),
}
for _, callee := range r.funcs {
j.Callees = append(j.Callees, &serial.Callee{
Name: callee.String(),
Pos: fset.Position(callee.Pos()).String(),
})
}
return toJSON(j)
}
func (r *calleesTypesResult) PrintPlain(printf printfFunc) {
printf(r.site, "this static function call dispatches to:")
printf(r.callee, "\t%s", r.callee.FullName())
}
func (r *calleesTypesResult) JSON(fset *token.FileSet) []byte {
j := &serial.Callees{
Pos: fset.Position(r.site.Pos()).String(),
Desc: "static function call",
}
j.Callees = []*serial.Callee{
{
Name: r.callee.FullName(),
Pos: fset.Position(r.callee.Pos()).String(),
},
}
return toJSON(j)
}
// NB: byFuncPos is not deterministic across packages since it depends on load order.
// Use lessPos if the tests need it.
type byFuncPos []*ssa.Function
func (a byFuncPos) Len() int { return len(a) }
func (a byFuncPos) Less(i, j int) bool { return a[i].Pos() < a[j].Pos() }
func (a byFuncPos) Swap(i, j int) { a[i], a[j] = a[j], a[i] }