forked from tmc/ssaview
/
ssaview.go
134 lines (115 loc) · 3.07 KB
/
ssaview.go
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// ssaview is a small utlity that renders SSA code alongside input Go code
//
// Runs via HTTP on :8080 or the PORT environment variable
package main
import (
"bytes"
"encoding/json"
"fmt"
"go/build"
"go/token"
"io"
"net/http"
"os"
"sort"
"go/types"
"golang.org/x/tools/go/loader"
"golang.org/x/tools/go/ssa"
"golang.org/x/tools/go/ssa/ssautil"
// "golang.org/x/tools/go/types/typeutil"
)
const indexPage = "index.html"
type members []ssa.Member
func (m members) Len() int { return len(m) }
func (m members) Swap(i, j int) { m[i], m[j] = m[j], m[i] }
func (m members) Less(i, j int) bool { return m[i].Pos() < m[j].Pos() }
// toSSA converts go source to SSA
func toSSA(source io.Reader, fileName, packageName string, debug bool) ([]byte, error) {
// adopted from saa package example
conf := loader.Config{
Build: &build.Default,
}
file, err := conf.ParseFile(fileName, source)
if err != nil {
return nil, err
}
conf.CreateFromFiles("main.go", file)
prog, err := conf.Load()
if err != nil {
return nil, err
}
ssaProg := ssautil.CreateProgram(prog, ssa.NaiveForm|ssa.BuildSerially)
ssaProg.Build()
mainPkg := ssaProg.Package(prog.InitialPackages()[0].Pkg)
out := new(bytes.Buffer)
mainPkg.SetDebugMode(debug)
mainPkg.WriteTo(out)
mainPkg.Build()
// grab just the functions
// https://pkg.go.dev/go/types#MethodSet
funcs := members([]ssa.Member{})
for _, obj := range mainPkg.Members {
if obj.Token() == token.FUNC {
funcs = append(funcs, obj)
}
if obj.Token() == token.TYPE {
ms := mainPkg.Prog.MethodSets.MethodSet(obj.Type())
for i := 0; i < ms.Len(); i++ {
ssaMeth := ssaProg.LookupMethod(obj.Type(), mainPkg.Pkg, ms.At(i).Obj().Name())
if ssaMeth != nil {
ssaMeth.WriteTo(out)
}
}
msp := mainPkg.Prog.MethodSets.MethodSet(types.NewPointer(obj.Type()))
for i := 0; i < msp.Len(); i++ {
ssaMeth := ssaProg.LookupMethod(types.NewPointer(obj.Type()), mainPkg.Pkg, msp.At(i).Obj().Name())
if ssaMeth != nil {
ssaMeth.WriteTo(out)
}
}
}
}
// sort by Pos()
sort.Sort(funcs)
for _, f := range funcs {
mainPkg.Func(f.Name()).WriteTo(out)
}
return out.Bytes(), nil
}
// writeJSON attempts to serialize data and write it to w
// On error it will write an HTTP status of 400
func writeJSON(w http.ResponseWriter, data interface{}) error {
if err, ok := data.(error); ok {
data = struct{ Error string }{err.Error()}
w.WriteHeader(400)
}
o, err := json.MarshalIndent(data, "", " ")
if err != nil {
return err
}
_, err = w.Write(o)
return err
}
func main() {
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
f, err := os.Open(indexPage)
if err != nil {
writeJSON(w, err)
}
io.Copy(w, f)
})
http.HandleFunc("/ssa", func(w http.ResponseWriter, r *http.Request) {
ssa, err := toSSA(r.Body, "main.go", "main", false)
if err != nil {
writeJSON(w, err)
return
}
defer r.Body.Close()
writeJSON(w, struct{ All string }{string(ssa)})
})
port := os.Getenv("PORT")
if port == "" {
port = "8080"
}
fmt.Println(http.ListenAndServe(":"+port, nil))
}