Golang importer.New函数代码示例

func TestLoadInitialPackages(t *testing.T) {
	ctxt := &importer.Config{Build: &build.Default}

	// Failed load: bad first import path causes parsePackageFiles to fail.
	args := []string{"nosuchpkg", "errors"}
	if _, _, err := importer.New(ctxt).LoadInitialPackages(args); err == nil {
		t.Errorf("LoadInitialPackages(%q) succeeded, want failure", args)
	} else {
		// cannot find package: ok.
	}

	// Failed load: bad second import path proceeds to doImport0, which fails.
	args = []string{"errors", "nosuchpkg"}
	if _, _, err := importer.New(ctxt).LoadInitialPackages(args); err == nil {
		t.Errorf("LoadInitialPackages(%q) succeeded, want failure", args)
	} else {
		// cannot find package: ok
	}

	// Successful load.
	args = []string{"fmt", "errors", "testdata/a.go,testdata/b.go", "--", "surplus"}
	imp := importer.New(ctxt)
	infos, rest, err := imp.LoadInitialPackages(args)
	if err != nil {
		t.Errorf("LoadInitialPackages(%q) failed: %s", args, err)
		return
	}
	if got, want := fmt.Sprint(rest), "[surplus]"; got != want {
		t.Errorf("LoadInitialPackages(%q) rest: got %s, want %s", got, want)
	}
	// Check list of initial packages.
	var pkgnames []string
	for _, info := range infos {
		pkgnames = append(pkgnames, info.Pkg.Path())
	}
	// Only the first import path (currently) contributes tests.
	if got, want := fmt.Sprint(pkgnames), "[fmt fmt_test errors P]"; got != want {
		t.Errorf("InitialPackages: got %s, want %s", got, want)
	}
	// Check set of transitive packages.
	// There are >30 and the set may grow over time, so only check a few.
	all := map[string]struct{}{}
	for _, info := range imp.AllPackages() {
		all[info.Pkg.Path()] = struct{}{}
	}
	want := []string{"strings", "time", "runtime", "testing", "unicode"}
	for _, w := range want {
		if _, ok := all[w]; !ok {
			t.Errorf("AllPackages: want element %s, got set %v", w, all)
		}
	}
}

// toSSA converts go source to SSA
func toSSA(source io.Reader, fileName, packageName string, debug bool) ([]byte, error) {
	// adopted from saa package example
	imp := importer.New(&importer.Config{Build: &build.Default})
	file, err := parser.ParseFile(imp.Fset, fileName, source, 0)
	if err != nil {
		return nil, err
	}
	mainInfo := imp.CreatePackage(packageName, file)
	var mode ssa.BuilderMode
	prog := ssa.NewProgram(imp.Fset, mode)
	if err := prog.CreatePackages(imp); err != nil {
		return nil, err
	}
	mainPkg := prog.Package(mainInfo.Pkg)
	out := new(bytes.Buffer)
	mainPkg.SetDebugMode(debug)
	mainPkg.DumpTo(out)
	mainPkg.Build()

	// grab just the functions
	funcs := members([]ssa.Member{})
	for _, obj := range mainPkg.Members {
		if obj.Token() == token.FUNC {
			funcs = append(funcs, obj)
		}
	}
	// sort by Pos()
	sort.Sort(funcs)
	for _, f := range funcs {
		mainPkg.Func(f.Name()).DumpTo(out)
	}
	return out.Bytes(), nil
}

func run(t *testing.T, dir, input string) bool {
	fmt.Printf("Input: %s\n", input)

	start := time.Now()

	var inputs []string
	for _, i := range strings.Split(input, " ") {
		inputs = append(inputs, dir+i)
	}

	imp := importer.New(&importer.Config{Build: &build.Default})
	// TODO(adonovan): use LoadInitialPackages, then un-export ParseFiles.
	files, err := importer.ParseFiles(imp.Fset, ".", inputs...)
	if err != nil {
		t.Errorf("ssa.ParseFiles(%s) failed: %s", inputs, err.Error())
		return false
	}

	// Print a helpful hint if we don't make it to the end.
	var hint string
	defer func() {
		if hint != "" {
			fmt.Println("FAIL")
			fmt.Println(hint)
		} else {
			fmt.Println("PASS")
		}
	}()

	hint = fmt.Sprintf("To dump SSA representation, run:\n%% go build code.google.com/p/go.tools/cmd/ssadump && ./ssadump -build=CFP %s\n", input)
	mainInfo := imp.LoadMainPackage(files...)

	prog := ssa.NewProgram(imp.Fset, ssa.SanityCheckFunctions)
	if err := prog.CreatePackages(imp); err != nil {
		t.Errorf("CreatePackages failed: %s", err)
		return false
	}
	prog.BuildAll()

	mainPkg := prog.Package(mainInfo.Pkg)
	mainPkg.CreateTestMainFunction() // (no-op if main already exists)

	hint = fmt.Sprintf("To trace execution, run:\n%% go build code.google.com/p/go.tools/cmd/ssadump && ./ssadump -build=C -run --interp=T %s\n", input)
	if exitCode := interp.Interpret(mainPkg, 0, inputs[0], []string{}); exitCode != 0 {
		t.Errorf("interp.Interpret(%s) exited with code %d, want zero", inputs, exitCode)
		return false
	}

	hint = "" // call off the hounds

	if false {
		fmt.Println(input, time.Since(start)) // test profiling
	}

	return true
}

func TestSwitches(t *testing.T) {
	imp := importer.New(new(importer.Config)) // (uses GCImporter)
	f, err := parser.ParseFile(imp.Fset, "testdata/switches.go", nil, parser.ParseComments)
	if err != nil {
		t.Error(err)
		return
	}

	mainInfo := imp.CreatePackage("main", f)

	prog := ssa.NewProgram(imp.Fset, 0)
	if err := prog.CreatePackages(imp); err != nil {
		t.Error(err)
		return
	}
	mainPkg := prog.Package(mainInfo.Pkg)
	mainPkg.Build()

	for _, mem := range mainPkg.Members {
		if fn, ok := mem.(*ssa.Function); ok {
			if fn.Synthetic != "" {
				continue // e.g. init()
			}
			// Each (multi-line) "switch" comment within
			// this function must match the printed form
			// of a ConstSwitch.
			var wantSwitches []string
			for _, c := range f.Comments {
				if fn.Syntax().Pos() <= c.Pos() && c.Pos() < fn.Syntax().End() {
					text := strings.TrimSpace(c.Text())
					if strings.HasPrefix(text, "switch ") {
						wantSwitches = append(wantSwitches, text)
					}
				}
			}

			switches := ssautil.Switches(fn)
			if len(switches) != len(wantSwitches) {
				t.Errorf("in %s, found %d switches, want %d", fn, len(switches), len(wantSwitches))
			}
			for i, sw := range switches {
				got := sw.String()
				if i >= len(wantSwitches) {
					continue
				}
				want := wantSwitches[i]
				if got != want {
					t.Errorf("in %s, found switch %d: got <<%s>>, want <<%s>>", fn, i, got, want)
				}
			}
		}
	}
}

func TestMultipleQueries(t *testing.T) {
	// Importer
	var buildContext = build.Default
	buildContext.GOPATH = "testdata"
	imp := importer.New(&importer.Config{Build: &buildContext})

	// Oracle
	filename := "testdata/src/main/multi.go"
	o, err := oracle.New(imp, []string{filename}, nil, true)
	if err != nil {
		t.Fatalf("oracle.New failed: %s", err)
	}

	// QueryPos
	pos := filename + ":#54,#58"
	qpos, err := oracle.ParseQueryPos(imp, pos, true)
	if err != nil {
		t.Fatalf("oracle.ParseQueryPos(%q) failed: %s", pos, err)
	}
	// SSA is built and we have the QueryPos.
	// Release the other ASTs and type info to the GC.
	imp = nil

	// Run different query moes on same scope and selection.
	out := new(bytes.Buffer)
	for _, mode := range [...]string{"callers", "describe", "freevars"} {
		res, err := o.Query(mode, qpos)
		if err != nil {
			t.Errorf("(*oracle.Oracle).Query(%q) failed: %s", pos, err)
		}
		capture := new(bytes.Buffer) // capture standard output
		res.WriteTo(capture)
		for _, line := range strings.Split(capture.String(), "\n") {
			fmt.Fprintf(out, "%s\n", stripLocation(line))
		}
	}
	want := `multi.f is called from these 1 sites:
	static function call from multi.main

function call (or conversion) of type ()

Free identifiers:
var x int

`
	if got := out.String(); got != want {
		t.Errorf("Query output differs; want <<%s>>, got <<%s>>\n", want, got)
	}
}

// Query runs a single oracle query.
//
// args specify the main package in importer.LoadInitialPackages syntax.
// mode is the query mode ("callers", etc).
// ptalog is the (optional) pointer-analysis log file.
// buildContext is the go/build configuration for locating packages.
// reflection determines whether to model reflection soundly (currently slow).
//
// Clients that intend to perform multiple queries against the same
// analysis scope should use this pattern instead:
//
//	imp := importer.New(&importer.Config{Build: buildContext})
// 	o, err := oracle.New(imp, args, nil)
//	if err != nil { ... }
//	for ... {
//		qpos, err := oracle.ParseQueryPos(imp, pos, needExact)
//		if err != nil { ... }
//
//		res, err := o.Query(mode, qpos)
//		if err != nil { ... }
//
//		// use res
//	}
//
// TODO(adonovan): the ideal 'needsExact' parameter for ParseQueryPos
// depends on the query mode; how should we expose this?
//
func Query(args []string, mode, pos string, ptalog io.Writer, buildContext *build.Context, reflection bool) (*Result, error) {
	if mode == "what" {
		// Bypass package loading, type checking, SSA construction.
		return what(pos, buildContext)
	}

	minfo := findMode(mode)
	if minfo == nil {
		return nil, fmt.Errorf("invalid mode type: %q", mode)
	}

	impcfg := importer.Config{Build: buildContext}

	// For queries needing only a single typed package,
	// reduce the analysis scope to that package.
	if minfo.needs&(needSSA|needRetainTypeInfo) == 0 {
		reduceScope(pos, &impcfg, &args)
	}

	// TODO(adonovan): report type errors to the user via Serial
	// types, not stderr?
	// impcfg.TypeChecker.Error = func(err error) {
	// 	E := err.(types.Error)
	// 	fmt.Fprintf(os.Stderr, "%s: %s\n", E.Fset.Position(E.Pos), E.Msg)
	// }
	imp := importer.New(&impcfg)
	o, err := newOracle(imp, args, ptalog, minfo.needs, reflection)
	if err != nil {
		return nil, err
	}

	var qpos *QueryPos
	if minfo.needs&(needPos|needExactPos) != 0 {
		qpos, err = ParseQueryPos(imp, pos, minfo.needs&needExactPos != 0)
		if err != nil {
			return nil, err
		}
	}

	// SSA is built and we have the QueryPos.
	// Release the other ASTs and type info to the GC.
	imp = nil

	return o.query(minfo, qpos)
}

// main creates a Go program that adds to a github.com/0xfaded/eval
// environment (of type eval.Env) the transitive closure of imports
// for a given starting package. Here we use github.com/0xfaded/eval.
func main() {
	startingImport := DefaultStartingImport
	if len(os.Args) == 2 {
		startingImport = os.Args[1]
	} else if len(os.Args) > 2 {
		fmt.Printf("usage: %s [starting-import]\n")
		os.Exit(1)
	}
	fmt.Printf("// starting import: \"%s\"\n", startingImport)

	impctx := importer.Config{Build: &build.Default}

	// Load, parse and type-check the program.
	imp := importer.New(&impctx)

	var pkgs_string []string = make([]string, 0, 10)
	pkgs_string = append(pkgs_string, startingImport)
	//pkgs_string = append(pkgs_string, "fmt")

	pkg_infos, _, err := imp.LoadInitialPackages(pkgs_string)
	if err != nil {
		log.Fatal(err)
	}

	pkg_infos = imp.AllPackages()
	var errpkgs []string

	pkg_infos = writePreamble(pkg_infos, "Eval", startingImport)

	for _, pkg_info := range pkg_infos {
		if pkg_info.Err != nil {
			errpkgs = append(errpkgs, pkg_info.Pkg.Path())
		} else {
			extractPackageSymbols(pkg_info, imp)
		}
	}
	if errpkgs != nil {
		log.Fatal("couldn't create these SSA packages due to type errors: %s",
			strings.Join(errpkgs, ", "))
	}

	writePostamble()

}

// CreateTestMainPackage should return nil if there were no tests.
func TestNullTestmainPackage(t *testing.T) {
	imp := importer.New(&importer.Config{Build: &build.Default})
	files, err := importer.ParseFiles(imp.Fset, ".", "testdata/b_test.go")
	if err != nil {
		t.Fatalf("ParseFiles failed: %s", err)
	}
	mainInfo := imp.CreatePackage("b", files...)
	prog := ssa.NewProgram(imp.Fset, ssa.SanityCheckFunctions)
	if err := prog.CreatePackages(imp); err != nil {
		t.Fatalf("CreatePackages failed: %s", err)
	}
	mainPkg := prog.Package(mainInfo.Pkg)
	if mainPkg.Func("main") != nil {
		t.Fatalf("unexpected main function")
	}
	if prog.CreateTestMainPackage(mainPkg) != nil {
		t.Fatalf("CreateTestMainPackage returned non-nil")
	}
}

func main() {
	flag.Usage = func() { fmt.Fprint(os.Stderr, useHelp) }
	flag.CommandLine.Init(os.Args[0], flag.ContinueOnError)
	if err := flag.CommandLine.Parse(os.Args[1:]); err != nil {
		if err == flag.ErrHelp {
			fmt.Println(helpMessage)
			fmt.Println("Flags:")
			flag.PrintDefaults()
		}
		os.Exit(2)
	}
	args = flag.Args()
	if len(args) == 0 {
		fmt.Fprint(os.Stderr, "Error: no package arguments.\n"+useHelp)
		os.Exit(2)
	}

	var err error
	imp = importer.New(&importer.Config{Build: &build.Default})
	ora, err = oracle.New(imp, args, nil, false)
	if err != nil {
		log.Fatal(err)
	}
	files = scopeFiles(imp)
	packages = imp.AllPackages()
	sort.Sort(byPath(packages))

	registerHandlers()

	srv := &http.Server{Addr: *httpAddr}
	l, err := net.Listen("tcp", srv.Addr)
	if err != nil {
		log.Fatal(err)
	}
	if *open {
		url := fmt.Sprintf("http://localhost%s/", *httpAddr)
		if !startBrowser(url) {
			fmt.Println(url)
		}
	}
	log.Fatal(srv.Serve(l))
}

// Query runs a single oracle query.
//
// args specify the main package in importer.LoadInitialPackages syntax.
// mode is the query mode ("callers", etc).
// ptalog is the (optional) pointer-analysis log file.
// buildContext is the go/build configuration for locating packages.
// reflection determines whether to model reflection soundly (currently slow).
//
// Clients that intend to perform multiple queries against the same
// analysis scope should use this pattern instead:
//
//	imp := importer.New(&importer.Config{Build: buildContext})
// 	o, err := oracle.New(imp, args, nil)
//	if err != nil { ... }
//	for ... {
//		qpos, err := oracle.ParseQueryPos(imp, pos, needExact)
//		if err != nil { ... }
//
//		res, err := o.Query(mode, qpos)
//		if err != nil { ... }
//
//		// use res
//	}
//
// TODO(adonovan): the ideal 'needsExact' parameter for ParseQueryPos
// depends on the query mode; how should we expose this?
//
func Query(args []string, mode, pos string, ptalog io.Writer, buildContext *build.Context, reflection bool) (*Result, error) {
	minfo := findMode(mode)
	if minfo == nil {
		return nil, fmt.Errorf("invalid mode type: %q", mode)
	}

	imp := importer.New(&importer.Config{Build: buildContext})
	o, err := New(imp, args, ptalog, reflection)
	if err != nil {
		return nil, err
	}

	// Phase timing diagnostics.
	// TODO(adonovan): needs more work.
	// if false {
	// 	defer func() {
	// 		fmt.Println()
	// 		for name, duration := range o.timers {
	// 			fmt.Printf("# %-30s %s\n", name, duration)
	// 		}
	// 	}()
	// }

	var qpos *QueryPos
	if minfo.needs&(needPos|needExactPos) != 0 {
		var err error
		qpos, err = ParseQueryPos(imp, pos, minfo.needs&needExactPos != 0)
		if err != nil {
			return nil, err
		}
	}

	// SSA is built and we have the QueryPos.
	// Release the other ASTs and type info to the GC.
	imp = nil

	return o.query(minfo, qpos)
}

func doOneInput(input, filename string) bool {
	impctx := &importer.Config{Build: &build.Default}
	imp := importer.New(impctx)

	// Parsing.
	f, err := parser.ParseFile(imp.Fset, filename, input, 0)
	if err != nil {
		// TODO(adonovan): err is a scanner error list;
		// display all errors not just first?
		fmt.Println(err)
		return false
	}

	// Create single-file main package and import its dependencies.
	info := imp.CreatePackage("main", f)

	// SSA creation + building.
	prog := ssa.NewProgram(imp.Fset, ssa.SanityCheckFunctions)
	if err := prog.CreatePackages(imp); err != nil {
		fmt.Println(err)
		return false
	}
	prog.BuildAll()

	mainpkg := prog.Package(info.Pkg)
	ptrmain := mainpkg // main package for the pointer analysis
	if mainpkg.Func("main") == nil {
		// No main function; assume it's a test.
		ptrmain = prog.CreateTestMainPackage(mainpkg)
	}

	ok := true

	lineMapping := make(map[string]string) // maps "file:line" to @line tag

	// Parse expectations in this input.
	var exps []*expectation
	re := regexp.MustCompile("// *@([a-z]*) *(.*)$")
	lines := strings.Split(input, "\n")
	for linenum, line := range lines {
		linenum++ // make it 1-based
		if matches := re.FindAllStringSubmatch(line, -1); matches != nil {
			match := matches[0]
			kind, rest := match[1], match[2]
			e := &expectation{kind: kind, filename: filename, linenum: linenum}

			if kind == "line" {
				if rest == "" {
					ok = false
					e.errorf("@%s expectation requires identifier", kind)
				} else {
					lineMapping[fmt.Sprintf("%s:%d", filename, linenum)] = rest
				}
				continue
			}

			if e.needsProbe() && !strings.Contains(line, "print(") {
				ok = false
				e.errorf("@%s expectation must follow call to print(x)", kind)
				continue
			}

			switch kind {
			case "pointsto":
				e.args = split(rest, "|")

			case "types":
				for _, typstr := range split(rest, "|") {
					var t types.Type = types.Typ[types.Invalid] // means "..."
					if typstr != "..." {
						texpr, err := parser.ParseExpr(typstr)
						if err != nil {
							ok = false
							// Don't print err since its location is bad.
							e.errorf("'%s' is not a valid type", typstr)
							continue
						}
						mainFileScope := mainpkg.Object.Scope().Child(0)
						t, _, err = types.EvalNode(imp.Fset, texpr, mainpkg.Object, mainFileScope)
						if err != nil {
							ok = false
							// Don't print err since its location is bad.
							e.errorf("'%s' is not a valid type: %s", typstr, err)
							continue
						}
					}
					e.types = append(e.types, t)
				}

			case "calls":
				e.args = split(rest, "->")
				// TODO(adonovan): eagerly reject the
				// expectation if fn doesn't denote
				// existing function, rather than fail
				// the expectation after analysis.
				if len(e.args) != 2 {
					ok = false
					e.errorf("@calls expectation wants 'caller -> callee' arguments")
					continue
				}
//.........这里部分代码省略.........

func TestObjValueLookup(t *testing.T) {
	imp := importer.New(new(importer.Config)) // (uses GCImporter)
	f, err := parser.ParseFile(imp.Fset, "testdata/objlookup.go", nil, parser.ParseComments)
	if err != nil {
		t.Error(err)
		return
	}

	// Maps each var Ident (represented "name:linenum") to the
	// kind of ssa.Value we expect (represented "Constant", "&Alloc").
	expectations := make(map[string]string)

	// Find all annotations of form x::BinOp, &y::Alloc, etc.
	re := regexp.MustCompile(`(\b|&)?(\w*)::(\w*)\b`)
	for _, c := range f.Comments {
		text := c.Text()
		pos := imp.Fset.Position(c.Pos())
		for _, m := range re.FindAllStringSubmatch(text, -1) {
			key := fmt.Sprintf("%s:%d", m[2], pos.Line)
			value := m[1] + m[3]
			expectations[key] = value
		}
	}

	mainInfo := imp.CreatePackage("main", f)

	prog := ssa.NewProgram(imp.Fset, 0 /*|ssa.LogFunctions*/)
	if err := prog.CreatePackages(imp); err != nil {
		t.Error(err)
		return
	}
	mainPkg := prog.Package(mainInfo.Pkg)
	mainPkg.SetDebugMode(true)
	mainPkg.Build()

	// Gather all idents and objects in file.
	objs := make(map[types.Object]bool)
	var ids []*ast.Ident
	ast.Inspect(f, func(n ast.Node) bool {
		if id, ok := n.(*ast.Ident); ok {
			ids = append(ids, id)
			if obj := mainInfo.ObjectOf(id); obj != nil {
				objs[obj] = true
			}
		}
		return true
	})

	// Check invariants for func and const objects.
	for obj := range objs {
		switch obj := obj.(type) {
		case *types.Func:
			checkFuncValue(t, prog, obj)

		case *types.Const:
			checkConstValue(t, prog, obj)
		}
	}

	// Check invariants for var objects.
	// The result varies based on the specific Ident.
	for _, id := range ids {
		if id.Name == "_" {
			continue
		}
		if obj, ok := mainInfo.ObjectOf(id).(*types.Var); ok {
			ref, _ := importer.PathEnclosingInterval(f, id.Pos(), id.Pos())
			pos := imp.Fset.Position(id.Pos())
			exp := expectations[fmt.Sprintf("%s:%d", id.Name, pos.Line)]
			if exp == "" {
				t.Errorf("%s: no expectation for var ident %s ", pos, id.Name)
				continue
			}
			wantAddr := false
			if exp[0] == '&' {
				wantAddr = true
				exp = exp[1:]
			}
			checkVarValue(t, prog, mainPkg, ref, obj, exp, wantAddr)
		}
	}
}

// Ensure that, in debug mode, we can determine the ssa.Value
// corresponding to every ast.Expr.
func TestValueForExpr(t *testing.T) {
	imp := importer.New(new(importer.Config)) // (uses GCImporter)
	f, err := parser.ParseFile(imp.Fset, "testdata/valueforexpr.go", nil, parser.ParseComments)
	if err != nil {
		t.Error(err)
		return
	}

	mainInfo := imp.CreatePackage("main", f)

	prog := ssa.NewProgram(imp.Fset, 0)
	if err := prog.CreatePackages(imp); err != nil {
		t.Error(err)
		return
	}
	mainPkg := prog.Package(mainInfo.Pkg)
	mainPkg.SetDebugMode(true)
	mainPkg.Build()

	if false {
		// debugging
		for _, mem := range mainPkg.Members {
			if fn, ok := mem.(*ssa.Function); ok {
				fn.DumpTo(os.Stderr)
			}
		}
	}

	// Find the actual AST node for each canonical position.
	parenExprByPos := make(map[token.Pos]*ast.ParenExpr)
	ast.Inspect(f, func(n ast.Node) bool {
		if n != nil {
			if e, ok := n.(*ast.ParenExpr); ok {
				parenExprByPos[e.Pos()] = e
			}
		}
		return true
	})

	// Find all annotations of form /*@kind*/.
	for _, c := range f.Comments {
		text := strings.TrimSpace(c.Text())
		if text == "" || text[0] != '@' {
			continue
		}
		text = text[1:]
		pos := c.End() + 1
		position := imp.Fset.Position(pos)
		var e ast.Expr
		if target := parenExprByPos[pos]; target == nil {
			t.Errorf("%s: annotation doesn't precede ParenExpr: %q", position, text)
			continue
		} else {
			e = target.X
		}

		path, _ := importer.PathEnclosingInterval(f, pos, pos)
		if path == nil {
			t.Errorf("%s: can't find AST path from root to comment: %s", position, text)
			continue
		}

		fn := ssa.EnclosingFunction(mainPkg, path)
		if fn == nil {
			t.Errorf("%s: can't find enclosing function", position)
			continue
		}

		v, gotAddr := fn.ValueForExpr(e) // (may be nil)
		got := strings.TrimPrefix(fmt.Sprintf("%T", v), "*ssa.")
		if want := text; got != want {
			t.Errorf("%s: got value %q, want %q", position, got, want)
		}
		if v != nil {
			T := v.Type()
			if gotAddr {
				T = T.Underlying().(*types.Pointer).Elem() // deref
			}
			if !types.IsIdentical(T, mainInfo.TypeOf(e)) {
				t.Errorf("%s: got type %s, want %s", position, mainInfo.TypeOf(e), T)
			}
		}
	}
}

// This program demonstrates how to run the SSA builder on a "Hello,
// World!" program and shows the printed representation of packages,
// functions and instructions.
//
// Within the function listing, the name of each BasicBlock such as
// ".0.entry" is printed left-aligned, followed by the block's
// Instructions.
//
// For each instruction that defines an SSA virtual register
// (i.e. implements Value), the type of that value is shown in the
// right column.
//
// Build and run the ssadump.go program in this package if you want a
// standalone tool with similar functionality.
//
func Example() {
	const hello = `
package main

import "fmt"

const message = "Hello, World!"

func main() {
	fmt.Println(message)
}
`
	// 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, "hello.go", hello, 0)
	if err != nil {
		fmt.Print(err) // parse error
		return
	}

	// Create single-file main package and import its dependencies.
	mainInfo := imp.CreatePackage("main", 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)

	// Print out the package.
	mainPkg.DumpTo(os.Stdout)

	// Build SSA code for bodies of functions in mainPkg.
	mainPkg.Build()

	// Print out the package-level functions.
	mainPkg.Func("init").DumpTo(os.Stdout)
	mainPkg.Func("main").DumpTo(os.Stdout)

	// Output:
	//
	// package main:
	//   func  init       func()
	//   var   init$guard bool
	//   func  main       func()
	//   const message    message = "Hello, World!":untyped string
	//
	// # Name: main.init
	// # Package: main
	// # Synthetic: package initializer
	// func init():
	// .0.entry:                                                               P:0 S:2
	// 	t0 = *init$guard                                                   bool
	// 	if t0 goto 2.init.done else 1.init.start
	// .1.init.start:                                                          P:1 S:1
	// 	*init$guard = true:bool
	// 	t1 = fmt.init()                                                      ()
	// 	jump 2.init.done
	// .2.init.done:                                                           P:2 S:0
	// 	return
	//
	// # Name: main.main
	// # Package: main
	// # Location: hello.go:8:6
	// func main():
	// .0.entry:                                                               P:0 S:0
	// 	t0 = new [1]interface{} (varargs)                       *[1]interface{}
	// 	t1 = &t0[0:untyped integer]                                *interface{}
	// 	t2 = make interface{} <- string ("Hello, World!":string)    interface{}
	// 	*t1 = t2
	// 	t3 = slice t0[:]                                          []interface{}
	// 	t4 = fmt.Println(t3)                                 (n int, err error)
	// 	return
}

func TestStdlib(t *testing.T) {
	impctx := importer.Config{Build: &build.Default}

	// Load, parse and type-check the program.
	t0 := time.Now()

	imp := importer.New(&impctx)

	if _, _, err := imp.LoadInitialPackages(allPackages()); err != nil {
		t.Errorf("LoadInitialPackages failed: %s", err)
		return
	}

	t1 := time.Now()

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

	// Create SSA packages.
	prog := ssa.NewProgram(imp.Fset, ssa.SanityCheckFunctions)
	if err := prog.CreatePackages(imp); err != nil {
		t.Errorf("CreatePackages failed: %s", err)
		return
	}
	// Enable debug mode globally.
	for _, info := range imp.AllPackages() {
		prog.Package(info.Pkg).SetDebugMode(debugMode)
	}

	t2 := time.Now()

	// Build SSA IR... if it's safe.
	prog.BuildAll()

	t3 := time.Now()

	runtime.GC()
	runtime.ReadMemStats(&memstats)

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

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

	t.Log("GOMAXPROCS:           ", runtime.GOMAXPROCS(0))
	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:                  ", (memstats.Alloc-alloc)/1000000)
}