mirror of
https://github.com/golang/go
synced 2024-11-19 04:24:39 -07:00
109 lines
2.4 KiB
Go
109 lines
2.4 KiB
Go
// 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 pointer_test
|
|
|
|
import (
|
|
"fmt"
|
|
"go/build"
|
|
"go/parser"
|
|
"sort"
|
|
|
|
"code.google.com/p/go.tools/importer"
|
|
"code.google.com/p/go.tools/pointer"
|
|
"code.google.com/p/go.tools/ssa"
|
|
)
|
|
|
|
// This program demonstrates how to use the pointer analysis to
|
|
// obtain a conservative call-graph of a Go program.
|
|
//
|
|
func Example() {
|
|
const myprog = `
|
|
package main
|
|
|
|
import "fmt"
|
|
|
|
type I interface {
|
|
f()
|
|
}
|
|
|
|
type C struct{}
|
|
|
|
func (C) f() {
|
|
fmt.Println("C.f()")
|
|
}
|
|
|
|
func main() {
|
|
var i I = C{}
|
|
i.f() // dynamic method call
|
|
}
|
|
`
|
|
// Construct an importer.
|
|
// Imports will be loaded as if by 'go build'.
|
|
imp := importer.New(&importer.Config{Build: &build.Default})
|
|
|
|
// Parse the input file.
|
|
file, err := parser.ParseFile(imp.Fset, "myprog.go", myprog, parser.DeclarationErrors)
|
|
if err != nil {
|
|
fmt.Print(err) // parse error
|
|
return
|
|
}
|
|
|
|
// Create a "main" package containing one file.
|
|
mainInfo := imp.LoadMainPackage(file)
|
|
|
|
// Create SSA-form program representation.
|
|
var mode ssa.BuilderMode
|
|
prog := ssa.NewProgram(imp.Fset, mode)
|
|
if err := prog.CreatePackages(imp); err != nil {
|
|
fmt.Print(err) // type error in some package
|
|
return
|
|
}
|
|
mainPkg := prog.Package(mainInfo.Pkg)
|
|
|
|
// Build SSA code for bodies of all functions in the whole program.
|
|
prog.BuildAll()
|
|
|
|
// Run the pointer analysis and build the complete callgraph.
|
|
callgraph := make(pointer.CallGraph)
|
|
config := &pointer.Config{
|
|
Mains: []*ssa.Package{mainPkg},
|
|
Call: callgraph.AddEdge,
|
|
}
|
|
root := pointer.Analyze(config)
|
|
|
|
// Visit callgraph in depth-first order.
|
|
//
|
|
// There may be multiple nodes for the
|
|
// same function due to context sensitivity.
|
|
var edges []string // call edges originating from the main package.
|
|
seen := make(map[pointer.CallGraphNode]bool)
|
|
var visit func(cgn pointer.CallGraphNode)
|
|
visit = func(cgn pointer.CallGraphNode) {
|
|
if seen[cgn] {
|
|
return // already seen
|
|
}
|
|
seen[cgn] = true
|
|
caller := cgn.Func()
|
|
for callee := range callgraph[cgn] {
|
|
if caller.Pkg == mainPkg {
|
|
edges = append(edges, fmt.Sprint(caller, " --> ", callee.Func()))
|
|
}
|
|
visit(callee)
|
|
}
|
|
}
|
|
visit(root)
|
|
|
|
// Print the edges in sorted order.
|
|
sort.Strings(edges)
|
|
for _, edge := range edges {
|
|
fmt.Println(edge)
|
|
}
|
|
|
|
// Output:
|
|
// (main.C).f --> fmt.Println
|
|
// main.init --> fmt.init
|
|
// main.main --> (main.C).f
|
|
}
|