// Create a pointer.Config whose scope is the initial packages of lprog
// and their dependencies.
func setupPTA(prog *ssa.Program, lprog *loader.Program, ptaLog io.Writer, reflection bool) (*pointer.Config, error) {
// TODO(adonovan): the body of this function is essentially
// duplicated in all go/pointer clients. Refactor.
// For each initial package (specified on the command line),
// if it has a main function, analyze that,
// otherwise analyze its tests, if any.
var testPkgs, mains []*ssa.Package
for _, info := range lprog.InitialPackages() {
initialPkg := prog.Package(info.Pkg)
// Add package to the pointer analysis scope.
if initialPkg.Func("main") != nil {
mains = append(mains, initialPkg)
} else {
testPkgs = append(testPkgs, initialPkg)
}
}
if testPkgs != nil {
if p := prog.CreateTestMainPackage(testPkgs...); p != nil {
mains = append(mains, p)
}
}
if mains == nil {
return nil, fmt.Errorf("analysis scope has no main and no tests")
}
return &pointer.Config{
Log: ptaLog,
Reflection: reflection,
Mains: mains,
}, nil
}
// FindMains returns the set of all packages loaded into the given
// loader.Program which contain main functions
func FindMains(p *loader.Program, s *ssa.Program) []*ssa.Package {
ips := p.InitialPackages()
mains := make([]*ssa.Package, 0, len(ips))
for _, info := range ips {
ssaPkg := s.Package(info.Pkg)
if ssaPkg.Func("main") != nil {
mains = append(mains, ssaPkg)
}
}
return mains
}
// ssaValueForExpr returns the ssa.Value of the non-ast.Ident
// expression whose path to the root of the AST is path.
//
func ssaValueForExpr(prog *ssa.Program, qinfo *loader.PackageInfo, path []ast.Node) (value ssa.Value, isAddr bool, err error) {
pkg := prog.Package(qinfo.Pkg)
pkg.SetDebugMode(true)
pkg.Build()
fn := ssa.EnclosingFunction(pkg, path)
if fn == nil {
return nil, false, fmt.Errorf("no SSA function built for this location (dead code?)")
}
if v, addr := fn.ValueForExpr(path[0].(ast.Expr)); v != nil {
return v, addr, nil
}
return nil, false, fmt.Errorf("can't locate SSA Value for expression in %s", fn)
}
// ssaValueForIdent returns the ssa.Value for the ast.Ident whose path
// to the root of the AST is path. isAddr reports whether the
// ssa.Value is the address denoted by the ast.Ident, not its value.
//
func ssaValueForIdent(prog *ssa.Program, qinfo *loader.PackageInfo, obj types.Object, path []ast.Node) (value ssa.Value, isAddr bool, err error) {
switch obj := obj.(type) {
case *types.Var:
pkg := prog.Package(qinfo.Pkg)
pkg.Build()
if v, addr := prog.VarValue(obj, pkg, path); v != nil {
return v, addr, nil
}
return nil, false, fmt.Errorf("can't locate SSA Value for var %s", obj.Name())
case *types.Func:
fn := prog.FuncValue(obj)
if fn == nil {
return nil, false, fmt.Errorf("%s is an interface method", obj)
}
// TODO(adonovan): there's no point running PTA on a *Func ident.
// Eliminate this feature.
return fn, false, nil
}
panic(obj)
}
// Create a pointer.Config whose scope is the initial packages of lprog
// and their dependencies.
func setupPTA(prog *ssa.Program, lprog *loader.Program, ptaLog io.Writer, reflection bool) (*pointer.Config, error) {
// For each initial package (specified on the command line),
// if it has a main function, analyze that,
// otherwise analyze its tests, if any.
var mains []*ssa.Package
for _, info := range lprog.InitialPackages() {
p := prog.Package(info.Pkg)
// Add package to the pointer analysis scope.
if p.Pkg.Name() == "main" && p.Func("main") != nil {
mains = append(mains, p)
} else if main := prog.CreateTestMainPackage(p); main != nil {
mains = append(mains, main)
}
}
if mains == nil {
return nil, fmt.Errorf("analysis scope has no main and no tests")
}
return &pointer.Config{
Log: ptaLog,
Reflection: reflection,
Mains: mains,
}, nil
}
func toSSA(src io.Reader, file, pkg string) (SSA, error) {
var fs []Func
var conf loader.Config
// Parse the file into a ssa file
f, _ := conf.ParseFile(file, src)
conf.CreateFromFiles("main.go", f)
p, _ := conf.Load()
buildsanity := content["ssabuild"] == true
var ssap *ssa.Program
if buildsanity {
ssap = ssautil.CreateProgram(p, ssa.SanityCheckFunctions)
} else {
ssap = ssautil.CreateProgram(p, ssa.NaiveForm)
}
// Build ssa prog to retrieve all information and the main pkg
ssap.Build()
mainpkg := ssap.Package(p.InitialPackages()[0].Pkg)
for _, m := range mainpkg.Members {
if m.Token() == token.FUNC {
f, ok := m.(*ssa.Function)
if ok {
var params []Value
for _, p := range f.Params {
v := Value{p.Name(), reflect.TypeOf(p).String()}
params = append(params, v)
}
var freevars []Value
for _, fv := range f.FreeVars {
v := Value{fv.Name(), reflect.TypeOf(fv).String()}
freevars = append(freevars, v)
}
var locals []Value
for _, l := range f.Locals {
v := Value{l.Name(), reflect.TypeOf(l).String()}
locals = append(locals, v)
}
var blocks []BB
for _, b := range f.Blocks {
var instrs []Instr
for _, i := range b.Instrs {
in := Instr{i.String(), reflect.TypeOf(i).String()}
instrs = append(instrs, in)
}
var preds []int
for _, p := range b.Preds {
preds = append(preds, p.Index)
}
var succs []int
for _, s := range b.Succs {
succs = append(succs, s.Index)
}
bb := BB{b.Index, instrs, preds, succs}
blocks = append(blocks, bb)
}
fn := Func{f.Name(), params, "par_" + f.Name(), freevars, "freevars_" + f.Name(), locals, "locals_" + f.Name(), blocks, "blocks_" + f.Name()}
fs = append(fs, fn)
}
}
}
return SSA{fs}, nil
}
// Returns true if unused
func checkObj(expr *ast.Ident, object types.Object, prog *loader.Program, ssaprog *ssa.Program, fset *token.FileSet) (unused bool) {
if _, ok := object.(*types.Var); !ok {
if debug {
fmt.Println("Skipping object", object)
}
return false
}
pkg, node, _ := prog.PathEnclosingInterval(expr.Pos(), expr.End())
spkg := ssaprog.Package(pkg.Pkg)
f := ssa.EnclosingFunction(spkg, node)
if f == nil {
if debug {
fmt.Printf("Unknown function %v %v %v %v\n", fset.Position(expr.Pos()), object, pkg, prog)
}
return false
}
value, _ := f.ValueForExpr(expr)
// Unwrap unops and grab the value inside
if v, ok := value.(*ssa.UnOp); ok {
if debug {
fmt.Println("Unwrapping unop")
}
value = v.X
}
if debug {
fmt.Printf("%v %v: %v %#v\n", fset.Position(expr.Pos()), expr, object, value)
}
if _, ok := value.(*ssa.Global); ok {
if debug {
fmt.Printf(" is global\n")
}
return false
}
if value == nil {
if debug {
fmt.Println("Value is nil", object)
}
return false
}
refs := value.Referrers()
if refs == nil {
if debug {
fmt.Println("Referrers is nil", object)
}
return false
}
if debug {
fmt.Printf(" (refs) %v\n", refs)
}
hasRef := false
for _, r := range *refs {
_, ok := r.(*ssa.DebugRef)
hasRef = hasRef || !ok
if debug && !ok {
fmt.Printf("%v %v: %v %v\n", fset.Position(expr.Pos()), expr, object, r)
}
}
if !hasRef {
unused = true
}
return unused
}
