test: errorcheck auto-generated functions

Add an "errorcheckwithauto" action which performs error check
including lines with auto-generated functions (excluded by
default). Comment "// ERRORAUTO" matches these lines.

Add testcase for CL 29570 (as an example).

Updates #16016, #17186.

Change-Id: Iaba3727336cd602f3dda6b9e5f97dafe0848e632
Reviewed-on: https://go-review.googlesource.com/29652
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

test/live.go

-// errorcheck -0 -l -live -wb=0
+// errorcheckwithauto -0 -l -live -wb=0
 // +build !ppc64,!ppc64le
 // ppc64 needs a better tighten pass to make f18 pass
 
@@ -658,3 +658,10 @@ func ddd1(x, y *int) { // ERROR "live at entry to ddd1: x y$"
 func ddd2(a ...*int) { // ERROR "live at entry to ddd2: a$"
 	sink = a[0]
 }
+
+// issue 16016: autogenerated wrapper should have arguments live
+type T struct{}
+
+func (*T) Foo(ptr *int) {}
+
+type R struct{ *T } // ERRORAUTO "live at entry to \(\*R\)\.Foo: \.this ptr" "live at entry to R\.Foo: \.this ptr"

test/run.go

@@ -242,8 +242,7 @@ type test struct {
 	donec       chan bool // closed when done
 	dt          time.Duration
 
-	src    string
-	action string // "compile", "build", etc.
+	src string
 
 	tempDir string
 	err     error
@@ -457,15 +456,15 @@ func (t *test) run() {
 		pkgPos = pos // some files are intentionally malformed
 	}
 	if ok, why := shouldTest(t.src[:pkgPos], goos, goarch); !ok {
-		t.action = "skip"
 		if *showSkips {
-			fmt.Printf("%-20s %-20s: %s\n", t.action, t.goFileName(), why)
+			fmt.Printf("%-20s %-20s: %s\n", "skip", t.goFileName(), why)
 		}
 		return
 	}
 
 	var args, flags []string
 	wantError := false
+	wantAuto := false
 	singlefilepkgs := false
 	f := strings.Fields(action)
 	if len(f) > 0 {
@@ -477,27 +476,25 @@ func (t *test) run() {
 	switch action {
 	case "rundircmpout":
 		action = "rundir"
-		t.action = "rundir"
 	case "cmpout":
 		action = "run" // the run case already looks for <dir>/<test>.out files
-		fallthrough
 	case "compile", "compiledir", "build", "run", "runoutput", "rundir":
-		t.action = action
+		// nothing to do
 	case "errorcheckandrundir":
 		wantError = false // should be no error if also will run
-		fallthrough
+	case "errorcheckwithauto":
+		action = "errorcheck"
+		wantAuto = true
+		wantError = true
 	case "errorcheck", "errorcheckdir", "errorcheckoutput":
-		t.action = action
 		wantError = true
 	case "skip":
 		if *runSkips {
 			break
 		}
-		t.action = "skip"
 		return
 	default:
 		t.err = skipError("skipped; unknown pattern: " + action)
-		t.action = "??"
 		return
 	}
 
@@ -574,7 +571,7 @@ func (t *test) run() {
 		if *updateErrors {
 			t.updateErrors(string(out), long)
 		}
-		t.err = t.errorCheck(string(out), long, t.gofile)
+		t.err = t.errorCheck(string(out), wantAuto, long, t.gofile)
 		return
 
 	case "compile":
@@ -622,7 +619,7 @@ func (t *test) run() {
 			for _, name := range gofiles {
 				fullshort = append(fullshort, filepath.Join(longdir, name), name)
 			}
-			t.err = t.errorCheck(string(out), fullshort...)
+			t.err = t.errorCheck(string(out), wantAuto, fullshort...)
 			if t.err != nil {
 				break
 			}
@@ -758,7 +755,7 @@ func (t *test) run() {
 				return
 			}
 		}
-		t.err = t.errorCheck(string(out), tfile, "tmp__.go")
+		t.err = t.errorCheck(string(out), false, tfile, "tmp__.go")
 		return
 	}
 }
@@ -801,7 +798,7 @@ func (t *test) expectedOutput() string {
 	return string(b)
 }
 
-func splitOutput(out string) []string {
+func splitOutput(out string, wantAuto bool) []string {
 	// gc error messages continue onto additional lines with leading tabs.
 	// Split the output at the beginning of each line that doesn't begin with a tab.
 	// <autogenerated> lines are impossible to match so those are filtered out.
@@ -812,7 +809,7 @@ func splitOutput(out string) []string {
 		}
 		if strings.HasPrefix(line, "\t") {
 			res[len(res)-1] += "\n" + line
-		} else if strings.HasPrefix(line, "go tool") || strings.HasPrefix(line, "<autogenerated>") || strings.HasPrefix(line, "#") {
+		} else if strings.HasPrefix(line, "go tool") || strings.HasPrefix(line, "#") || !wantAuto && strings.HasPrefix(line, "<autogenerated>") {
 			continue
 		} else if strings.TrimSpace(line) != "" {
 			res = append(res, line)
@@ -821,14 +818,14 @@ func splitOutput(out string) []string {
 	return res
 }
 
-func (t *test) errorCheck(outStr string, fullshort ...string) (err error) {
+func (t *test) errorCheck(outStr string, wantAuto bool, fullshort ...string) (err error) {
 	defer func() {
 		if *verbose && err != nil {
 			log.Printf("%s gc output:\n%s", t, outStr)
 		}
 	}()
 	var errs []error
-	out := splitOutput(outStr)
+	out := splitOutput(outStr, wantAuto)
 
 	// Cut directory name.
 	for i := range out {
@@ -846,7 +843,11 @@ func (t *test) errorCheck(outStr string, fullshort ...string) (err error) {
 
 	for _, we := range want {
 		var errmsgs []string
-		errmsgs, out = partitionStrings(we.prefix, out)
+		if we.auto {
+			errmsgs, out = partitionStrings("<autogenerated>", out)
+		} else {
+			errmsgs, out = partitionStrings(we.prefix, out)
+		}
 		if len(errmsgs) == 0 {
 			errs = append(errs, fmt.Errorf("%s:%d: missing error %q", we.file, we.lineNum, we.reStr))
 			continue
@@ -906,7 +907,7 @@ func (t *test) updateErrors(out, file string) {
 	// Parse new errors.
 	errors := make(map[int]map[string]bool)
 	tmpRe := regexp.MustCompile(`autotmp_[0-9]+`)
-	for _, errStr := range splitOutput(out) {
+	for _, errStr := range splitOutput(out, false) {
 		colon1 := strings.Index(errStr, ":")
 		if colon1 < 0 || errStr[:colon1] != file {
 			continue
@@ -991,12 +992,14 @@ type wantedError struct {
 	reStr   string
 	re      *regexp.Regexp
 	lineNum int
+	auto    bool // match <autogenerated> line
 	file    string
 	prefix  string
 }
 
 var (
 	errRx       = regexp.MustCompile(`// (?:GC_)?ERROR (.*)`)
+	errAutoRx   = regexp.MustCompile(`// (?:GC_)?ERRORAUTO (.*)`)
 	errQuotesRx = regexp.MustCompile(`"([^"]*)"`)
 	lineRx      = regexp.MustCompile(`LINE(([+-])([0-9]+))?`)
 )
@@ -1011,7 +1014,13 @@ func (t *test) wantedErrors(file, short string) (errs []wantedError) {
 			// double comment disables ERROR
 			continue
 		}
-		m := errRx.FindStringSubmatch(line)
+		var auto bool
+		m := errAutoRx.FindStringSubmatch(line)
+		if m != nil {
+			auto = true
+		} else {
+			m = errRx.FindStringSubmatch(line)
+		}
 		if m == nil {
 			continue
 		}
@@ -1046,6 +1055,7 @@ func (t *test) wantedErrors(file, short string) (errs []wantedError) {
 				reStr:   rx,
 				re:      re,
 				prefix:  prefix,
+				auto:    auto,
 				lineNum: lineNum,
 				file:    short,
 			})