test: add ability to run tests with dynamic linking

This is a bit ugly but it's a useful test. Run go install -buildmode=shared std
and then go run run.go -linkshared (it passes on linux/amd64).

Change-Id: I5684c79cd03817fa1fc399788b7320f8535c08da
Reviewed-on: https://go-review.googlesource.com/16343Reviewed-by: Russ Cox <rsc@golang.org>

test/run.go

@@ -37,6 +37,7 @@ var (
 	numParallel    = flag.Int("n", runtime.NumCPU(), "number of parallel tests to run")
 	summary        = flag.Bool("summary", false, "show summary of results")
 	showSkips      = flag.Bool("show_skips", false, "show skipped tests")
+	linkshared     = flag.Bool("linkshared", false, "")
 	updateErrors   = flag.Bool("update_errors", false, "update error messages in test file based on compiler output")
 	runoutputLimit = flag.Int("l", defaultRunOutputLimit(), "number of parallel runoutput tests to run")
 
@@ -191,11 +192,19 @@ func goFiles(dir string) []string {
 type runCmd func(...string) ([]byte, error)
 
 func compileFile(runcmd runCmd, longname string) (out []byte, err error) {
-	return runcmd("go", "tool", "compile", "-e", longname)
+	cmd := []string{"go", "tool", "compile", "-e"}
+	if *linkshared {
+		cmd = append(cmd, "-dynlink", "-installsuffix=dynlink")
+	}
+	cmd = append(cmd, longname)
+	return runcmd(cmd...)
 }
 
 func compileInDir(runcmd runCmd, dir string, names ...string) (out []byte, err error) {
 	cmd := []string{"go", "tool", "compile", "-e", "-D", ".", "-I", "."}
+	if *linkshared {
+		cmd = append(cmd, "-dynlink", "-installsuffix=dynlink")
+	}
 	for _, name := range names {
 		cmd = append(cmd, filepath.Join(dir, name))
 	}
@@ -204,7 +213,12 @@ func compileInDir(runcmd runCmd, dir string, names ...string) (out []byte, err e
 
 func linkFile(runcmd runCmd, goname string) (err error) {
 	pfile := strings.Replace(goname, ".go", ".o", -1)
-	_, err = runcmd("go", "tool", "link", "-w", "-o", "a.exe", "-L", ".", pfile)
+	cmd := []string{"go", "tool", "link", "-w", "-o", "a.exe", "-L", "."}
+	if *linkshared {
+		cmd = append(cmd, "-linkshared", "-installsuffix=dynlink")
+	}
+	cmd = append(cmd, pfile)
+	_, err = runcmd(cmd...)
 	return
 }
 
@@ -513,6 +527,7 @@ func (t *test) run() {
 
 	case "errorcheck":
 		cmdline := []string{"go", "tool", "compile", "-e", "-o", "a.o"}
+		// No need to add -dynlink even if linkshared if we're just checking for errors...
 		cmdline = append(cmdline, flags...)
 		cmdline = append(cmdline, long)
 		out, err := runcmd(cmdline...)
@@ -628,7 +643,12 @@ func (t *test) run() {
 
 	case "run":
 		useTmp = false
-		out, err := runcmd(append([]string{"go", "run", t.goFileName()}, args...)...)
+		cmd := []string{"go", "run"}
+		if *linkshared {
+			cmd = append(cmd, "-linkshared")
+		}
+		cmd = append(cmd, t.goFileName())
+		out, err := runcmd(append(cmd, args...)...)
 		if err != nil {
 			t.err = err
 			return
@@ -643,7 +663,12 @@ func (t *test) run() {
 			<-rungatec
 		}()
 		useTmp = false
-		out, err := runcmd(append([]string{"go", "run", t.goFileName()}, args...)...)
+		cmd := []string{"go", "run"}
+		if *linkshared {
+			cmd = append(cmd, "-linkshared")
+		}
+		cmd = append(cmd, t.goFileName())
+		out, err := runcmd(append(cmd, args...)...)
 		if err != nil {
 			t.err = err
 			return
@@ -653,7 +678,12 @@ func (t *test) run() {
 			t.err = fmt.Errorf("write tempfile:%s", err)
 			return
 		}
-		out, err = runcmd("go", "run", tfile)
+		cmd = []string{"go", "run"}
+		if *linkshared {
+			cmd = append(cmd, "-linkshared")
+		}
+		cmd = append(cmd, tfile)
+		out, err = runcmd(cmd...)
 		if err != nil {
 			t.err = err
 			return
@@ -664,7 +694,12 @@ func (t *test) run() {
 
 	case "errorcheckoutput":
 		useTmp = false
-		out, err := runcmd(append([]string{"go", "run", t.goFileName()}, args...)...)
+		cmd := []string{"go", "run"}
+		if *linkshared {
+			cmd = append(cmd, "-linkshared")
+		}
+		cmd = append(cmd, t.goFileName())
+		out, err := runcmd(append(cmd, args...)...)
 		if err != nil {
 			t.err = err
 			return