tile38/vendor/honnef.co/go/tools/ir/irutil/visit.go

80 lines
2.0 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 irutil // import "honnef.co/go/tools/ir/irutil"
import "honnef.co/go/tools/ir"
// This file defines utilities for visiting the IR of
// a Program.
//
// TODO(adonovan): test coverage.
// AllFunctions finds and returns the set of functions potentially
// needed by program prog, as determined by a simple linker-style
// reachability algorithm starting from the members and method-sets of
// each package. The result may include anonymous functions and
// synthetic wrappers.
//
// Precondition: all packages are built.
//
func AllFunctions(prog *ir.Program) map[*ir.Function]bool {
visit := visitor{
prog: prog,
seen: make(map[*ir.Function]bool),
}
visit.program()
return visit.seen
}
type visitor struct {
prog *ir.Program
seen map[*ir.Function]bool
}
func (visit *visitor) program() {
for _, pkg := range visit.prog.AllPackages() {
for _, mem := range pkg.Members {
if fn, ok := mem.(*ir.Function); ok {
visit.function(fn)
}
}
}
for _, T := range visit.prog.RuntimeTypes() {
mset := visit.prog.MethodSets.MethodSet(T)
for i, n := 0, mset.Len(); i < n; i++ {
visit.function(visit.prog.MethodValue(mset.At(i)))
}
}
}
func (visit *visitor) function(fn *ir.Function) {
if !visit.seen[fn] {
visit.seen[fn] = true
var buf [10]*ir.Value // avoid alloc in common case
for _, b := range fn.Blocks {
for _, instr := range b.Instrs {
for _, op := range instr.Operands(buf[:0]) {
if fn, ok := (*op).(*ir.Function); ok {
visit.function(fn)
}
}
}
}
}
}
// MainPackages returns the subset of the specified packages
// named "main" that define a main function.
// The result may include synthetic "testmain" packages.
func MainPackages(pkgs []*ir.Package) []*ir.Package {
var mains []*ir.Package
for _, pkg := range pkgs {
if pkg.Pkg.Name() == "main" && pkg.Func("main") != nil {
mains = append(mains, pkg)
}
}
return mains
}