func TestStdlib(t *testing.T) {
	defer func(saved func(format string, args ...interface{})) {
		logf = saved
	}(logf)
	logf = t.Errorf

	ctxt := build.Default // copy

	// Enumerate $GOROOT packages.
	saved := ctxt.GOPATH
	ctxt.GOPATH = "" // disable GOPATH during AllPackages
	pkgs := buildutil.AllPackages(&ctxt)
	ctxt.GOPATH = saved

	// Throw in a number of go.tools packages too.
	pkgs = append(pkgs,
		"golang.org/x/tools/cmd/godoc",
		"golang.org/x/tools/refactor/lexical")

	// Load, parse and type-check the program.
	conf := loader.Config{Build: &ctxt}
	for _, path := range pkgs {
		conf.ImportWithTests(path)
	}
	iprog, err := conf.Load()
	if err != nil {
		t.Fatalf("Load failed: %v", err)
	}

	// This test ensures that Structure doesn't panic and that
	// its internal sanity-checks against go/types don't fail.
	for pkg, info := range iprog.AllPackages {
		_ = Structure(iprog.Fset, pkg, &info.Info, info.Files)
	}
}

// Create unexporter
func NewUnexporter(o *Config) (*unexporter, error) {

	var conf loader.Config
	for _, package_name := range buildutil.AllPackages(&build.Default) {
		conf.ImportWithTests(package_name)
	}
	program, err := conf.Load()
	if err != nil {
		return nil, err
	}

	if program.Package(o.Pkg) == nil {
		return nil, errors.New(fmt.Sprintf("'%s' is not a valid package", o.Pkg))
	}

	if o.Debug {
		pkg := program.Package(o.Pkg).Pkg
		fmt.Printf("finding unused identifiers for %s (%s)\n", pkg.Name(), pkg.Path())
	}

	unexporter := &unexporter{
		Program:     program,
		MainPackage: program.Package(o.Pkg),
		Verbose:     o.Debug,
	}

	unexporter.run()

	return unexporter, nil

}

func TestAllPackages(t *testing.T) {
	all := buildutil.AllPackages(&build.Default)

	set := make(map[string]bool)
	for _, pkg := range all {
		set[pkg] = true
	}

	const wantAtLeast = 250
	if len(all) < wantAtLeast {
		t.Errorf("Found only %d packages, want at least %d", len(all), wantAtLeast)
	}

	for _, want := range []string{"fmt", "crypto/sha256", "golang.org/x/tools/go/buildutil"} {
		if !set[want] {
			t.Errorf("Package %q not found; got %s", want, all)
		}
	}
}

func TestStdlib(t *testing.T) {
	// Load, parse and type-check the program.
	t0 := time.Now()
	alloc0 := bytesAllocated()

	// Load, parse and type-check the program.
	ctxt := build.Default // copy
	ctxt.GOPATH = ""      // disable GOPATH
	conf := loader.Config{Build: &ctxt}
	for _, path := range buildutil.AllPackages(conf.Build) {
		if skip[path] {
			continue
		}
		conf.ImportWithTests(path)
	}

	iprog, err := conf.Load()
	if err != nil {
		t.Fatalf("Load failed: %v", err)
	}

	t1 := time.Now()
	alloc1 := bytesAllocated()

	// Create SSA packages.
	var mode ssa.BuilderMode
	// Comment out these lines during benchmarking.  Approx SSA build costs are noted.
	mode |= ssa.SanityCheckFunctions // + 2% space, + 4% time
	mode |= ssa.GlobalDebug          // +30% space, +18% time
	prog := ssautil.CreateProgram(iprog, mode)

	t2 := time.Now()

	// Build SSA.
	prog.Build()

	t3 := time.Now()
	alloc3 := bytesAllocated()

	numPkgs := len(prog.AllPackages())
	if want := 140; numPkgs < want {
		t.Errorf("Loaded only %d packages, want at least %d", numPkgs, want)
	}

	// Keep iprog reachable until after we've measured memory usage.
	if len(iprog.AllPackages) == 0 {
		print() // unreachable
	}

	allFuncs := ssautil.AllFunctions(prog)

	// Check that all non-synthetic functions have distinct names.
	// Synthetic wrappers for exported methods should be distinct too,
	// except for unexported ones (explained at (*Function).RelString).
	byName := make(map[string]*ssa.Function)
	for fn := range allFuncs {
		if fn.Synthetic == "" || ast.IsExported(fn.Name()) {
			str := fn.String()
			prev := byName[str]
			byName[str] = fn
			if prev != nil {
				t.Errorf("%s: duplicate function named %s",
					prog.Fset.Position(fn.Pos()), str)
				t.Errorf("%s:   (previously defined here)",
					prog.Fset.Position(prev.Pos()))
			}
		}
	}

	// Dump some statistics.
	var numInstrs int
	for fn := range allFuncs {
		for _, b := range fn.Blocks {
			numInstrs += len(b.Instrs)
		}
	}

	// determine line count
	var lineCount int
	prog.Fset.Iterate(func(f *token.File) bool {
		lineCount += f.LineCount()
		return true
	})

	// NB: when benchmarking, don't forget to clear the debug +
	// sanity builder flags for better performance.

	t.Log("GOMAXPROCS:           ", runtime.GOMAXPROCS(0))
	t.Log("#Source lines:        ", lineCount)
	t.Log("Load/parse/typecheck: ", t1.Sub(t0))
	t.Log("SSA create:           ", t2.Sub(t1))
	t.Log("SSA build:            ", t3.Sub(t2))

	// SSA stats:
	t.Log("#Packages:            ", numPkgs)
	t.Log("#Functions:           ", len(allFuncs))
	t.Log("#Instructions:        ", numInstrs)
	t.Log("#MB AST+types:        ", int64(alloc1-alloc0)/1e6)
	t.Log("#MB SSA:              ", int64(alloc3-alloc1)/1e6)
}

func TestStdlib(t *testing.T) {
	if !*runStdlibTest {
		t.Skip("skipping (slow) stdlib test (use --stdlib)")
	}

	// Load, parse and type-check the program.
	ctxt := build.Default // copy
	ctxt.GOPATH = ""      // disable GOPATH
	conf := loader.Config{Build: &ctxt}
	if _, err := conf.FromArgs(buildutil.AllPackages(conf.Build), true); err != nil {
		t.Errorf("FromArgs failed: %v", err)
		return
	}

	iprog, err := conf.Load()
	if err != nil {
		t.Fatalf("Load failed: %v", err)
	}

	// Create SSA packages.
	prog := ssautil.CreateProgram(iprog, 0)
	prog.BuildAll()

	numPkgs := len(prog.AllPackages())
	if want := 240; numPkgs < want {
		t.Errorf("Loaded only %d packages, want at least %d", numPkgs, want)
	}

	// Determine the set of packages/tests to analyze.
	var testPkgs []*ssa.Package
	for _, info := range iprog.InitialPackages() {
		testPkgs = append(testPkgs, prog.Package(info.Pkg))
	}
	testmain := prog.CreateTestMainPackage(testPkgs...)
	if testmain == nil {
		t.Fatal("analysis scope has tests")
	}

	// Run the analysis.
	config := &Config{
		Reflection:     false, // TODO(adonovan): fix remaining bug in rVCallConstraint, then enable.
		BuildCallGraph: true,
		Mains:          []*ssa.Package{testmain},
	}
	// TODO(adonovan): add some query values (affects track bits).

	t0 := time.Now()

	result, err := Analyze(config)
	if err != nil {
		t.Fatal(err) // internal error in pointer analysis
	}
	_ = result // TODO(adonovan): measure something

	t1 := time.Now()

	// Dump some statistics.
	allFuncs := ssautil.AllFunctions(prog)
	var numInstrs int
	for fn := range allFuncs {
		for _, b := range fn.Blocks {
			numInstrs += len(b.Instrs)
		}
	}

	// determine line count
	var lineCount int
	prog.Fset.Iterate(func(f *token.File) bool {
		lineCount += f.LineCount()
		return true
	})

	t.Log("#Source lines:          ", lineCount)
	t.Log("#Instructions:          ", numInstrs)
	t.Log("Pointer analysis:       ", t1.Sub(t0))
}

func TestBExportData_stdlib(t *testing.T) {
	if runtime.GOOS == "android" {
		t.Skipf("incomplete std lib on %s", runtime.GOOS)
	}

	// Load, parse and type-check the program.
	ctxt := build.Default // copy
	ctxt.GOPATH = ""      // disable GOPATH
	conf := loader.Config{
		Build:       &ctxt,
		AllowErrors: true,
	}
	for _, path := range buildutil.AllPackages(conf.Build) {
		conf.Import(path)
	}

	// Create a package containing type and value errors to ensure
	// they are properly encoded/decoded.
	f, err := conf.ParseFile("haserrors/haserrors.go", `package haserrors
const UnknownValue = "" + 0
type UnknownType undefined
`)
	if err != nil {
		t.Fatal(err)
	}
	conf.CreateFromFiles("haserrors", f)

	prog, err := conf.Load()
	if err != nil {
		t.Fatalf("Load failed: %v", err)
	}

	numPkgs := len(prog.AllPackages)
	if want := 248; numPkgs < want {
		t.Errorf("Loaded only %d packages, want at least %d", numPkgs, want)
	}

	for pkg, info := range prog.AllPackages {
		if info.Files == nil {
			continue // empty directory
		}
		exportdata := gcimporter.BExportData(conf.Fset, pkg)

		imports := make(map[string]*types.Package)
		fset2 := token.NewFileSet()
		n, pkg2, err := gcimporter.BImportData(fset2, imports, exportdata, pkg.Path())
		if err != nil {
			t.Errorf("BImportData(%s): %v", pkg.Path(), err)
			continue
		}
		if n != len(exportdata) {
			t.Errorf("BImportData(%s) decoded %d bytes, want %d",
				pkg.Path(), n, len(exportdata))
		}

		// Compare the packages' corresponding members.
		for _, name := range pkg.Scope().Names() {
			if !ast.IsExported(name) {
				continue
			}
			obj1 := pkg.Scope().Lookup(name)
			obj2 := pkg2.Scope().Lookup(name)
			if obj2 == nil {
				t.Errorf("%s.%s not found, want %s", pkg.Path(), name, obj1)
				continue
			}

			fl1 := fileLine(conf.Fset, obj1)
			fl2 := fileLine(fset2, obj2)
			if fl1 != fl2 {
				t.Errorf("%s.%s: got posn %s, want %s",
					pkg.Path(), name, fl2, fl1)
			}

			if err := equalObj(obj1, obj2); err != nil {
				t.Errorf("%s.%s: %s\ngot:  %s\nwant: %s",
					pkg.Path(), name, err, obj2, obj1)
			}
		}
	}
}

func TestStdlib(t *testing.T) {
	if runtime.GOOS == "android" {
		t.Skipf("incomplete std lib on %s", runtime.GOOS)
	}

	runtime.GC()
	t0 := time.Now()
	var memstats runtime.MemStats
	runtime.ReadMemStats(&memstats)
	alloc := memstats.Alloc

	// Load, parse and type-check the program.
	ctxt := build.Default // copy
	ctxt.GOPATH = ""      // disable GOPATH
	conf := loader.Config{Build: &ctxt}
	for _, path := range buildutil.AllPackages(conf.Build) {
		conf.ImportWithTests(path)
	}

	prog, err := conf.Load()
	if err != nil {
		t.Fatalf("Load failed: %v", err)
	}

	t1 := time.Now()
	runtime.GC()
	runtime.ReadMemStats(&memstats)

	numPkgs := len(prog.AllPackages)
	if want := 205; numPkgs < want {
		t.Errorf("Loaded only %d packages, want at least %d", numPkgs, want)
	}

	// Dump package members.
	if false {
		for pkg := range prog.AllPackages {
			fmt.Printf("Package %s:\n", pkg.Path())
			scope := pkg.Scope()
			qualifier := types.RelativeTo(pkg)
			for _, name := range scope.Names() {
				if ast.IsExported(name) {
					fmt.Printf("\t%s\n", types.ObjectString(scope.Lookup(name), qualifier))
				}
			}
			fmt.Println()
		}
	}

	// Check that Test functions for io/ioutil, regexp and
	// compress/bzip2 are all simultaneously present.
	// (The apparent cycle formed when augmenting all three of
	// these packages by their tests was the original motivation
	// for reporting b/7114.)
	//
	// compress/bzip2.TestBitReader in bzip2_test.go    imports io/ioutil
	// io/ioutil.TestTempFile       in tempfile_test.go imports regexp
	// regexp.TestRE2Search         in exec_test.go     imports compress/bzip2
	for _, test := range []struct{ pkg, fn string }{
		{"io/ioutil", "TestTempFile"},
		{"regexp", "TestRE2Search"},
		{"compress/bzip2", "TestBitReader"},
	} {
		info := prog.Imported[test.pkg]
		if info == nil {
			t.Errorf("failed to load package %q", test.pkg)
			continue
		}
		obj, _ := info.Pkg.Scope().Lookup(test.fn).(*types.Func)
		if obj == nil {
			t.Errorf("package %q has no func %q", test.pkg, test.fn)
			continue
		}
	}

	// Dump some statistics.

	// determine line count
	var lineCount int
	prog.Fset.Iterate(func(f *token.File) bool {
		lineCount += f.LineCount()
		return true
	})

	t.Log("GOMAXPROCS:           ", runtime.GOMAXPROCS(0))
	t.Log("#Source lines:        ", lineCount)
	t.Log("Load/parse/typecheck: ", t1.Sub(t0))
	t.Log("#MB:                  ", int64(memstats.Alloc-alloc)/1000000)
}