diff --git a/misc/cgo/testcarchive/carchive_test.go b/misc/cgo/testcarchive/carchive_test.go
index a2b43bb72d..c5193e3f19 100644
--- a/misc/cgo/testcarchive/carchive_test.go
+++ b/misc/cgo/testcarchive/carchive_test.go
@@ -10,6 +10,7 @@ import (
 	"debug/elf"
 	"flag"
 	"fmt"
+	"io/fs"
 	"log"
 	"os"
 	"os/exec"
@@ -245,6 +246,29 @@ func testInstall(t *testing.T, exe, libgoa, libgoh string, buildcmd ...string) {
 
 var badLineRegexp = regexp.MustCompile(`(?m)^#line [0-9]+ "/.*$`)
 
+// checkIsExecutable verifies that exe exists and has execute permission.
+//
+// (https://golang.org/issue/49693 notes failures with "no such file or
+// directory", so we want to double-check that the executable actually exists
+// immediately after we build it in order to better understand that failure
+// mode.)
+func checkIsExecutable(t *testing.T, exe string) {
+	t.Helper()
+	fi, err := os.Stat(exe)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if runtime.GOOS == "windows" {
+		// os.File doesn't check the "execute" permission on Windows files
+		// and as a result doesn't set that bit in a file's permissions.
+		// Assume that if the file exists it is “executable enough”.
+		return
+	}
+	if fi.Mode()&0111 == 0 {
+		t.Fatalf("%s is not executable: %0o", exe, fi.Mode()&fs.ModePerm)
+	}
+}
+
 // checkLineComments checks that the export header generated by
 // -buildmode=c-archive doesn't have any absolute paths in the #line
 // comments. We don't want those paths because they are unhelpful for
@@ -310,7 +334,7 @@ func TestEarlySignalHandler(t *testing.T) {
 		defer func() {
 			os.Remove("libgo2.a")
 			os.Remove("libgo2.h")
-			os.Remove("testp")
+			os.Remove("testp" + exeSuffix)
 			os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 		}()
 	}
@@ -350,7 +374,7 @@ func TestSignalForwarding(t *testing.T) {
 		defer func() {
 			os.Remove("libgo2.a")
 			os.Remove("libgo2.h")
-			os.Remove("testp")
+			os.Remove("testp" + exeSuffix)
 			os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 		}()
 	}
@@ -374,7 +398,7 @@ func TestSignalForwarding(t *testing.T) {
 	cmd = exec.Command(bin[0], append(bin[1:], "1")...)
 
 	out, err := cmd.CombinedOutput()
-	t.Logf("%s", out)
+	t.Logf("%v\n%s", cmd.Args, out)
 	expectSignal(t, err, syscall.SIGSEGV)
 
 	// SIGPIPE is never forwarded on darwin. See golang.org/issue/33384.
@@ -383,7 +407,9 @@ func TestSignalForwarding(t *testing.T) {
 		cmd = exec.Command(bin[0], append(bin[1:], "3")...)
 
 		out, err = cmd.CombinedOutput()
-		t.Logf("%s", out)
+		if len(out) > 0 {
+			t.Logf("%s", out)
+		}
 		expectSignal(t, err, syscall.SIGPIPE)
 	}
 }
@@ -400,7 +426,7 @@ func TestSignalForwardingExternal(t *testing.T) {
 		defer func() {
 			os.Remove("libgo2.a")
 			os.Remove("libgo2.h")
-			os.Remove("testp")
+			os.Remove("testp" + exeSuffix)
 			os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 		}()
 	}
@@ -517,7 +543,7 @@ func TestOsSignal(t *testing.T) {
 		defer func() {
 			os.Remove("libgo3.a")
 			os.Remove("libgo3.h")
-			os.Remove("testp")
+			os.Remove("testp" + exeSuffix)
 			os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 		}()
 	}
@@ -554,7 +580,7 @@ func TestSigaltstack(t *testing.T) {
 		defer func() {
 			os.Remove("libgo4.a")
 			os.Remove("libgo4.h")
-			os.Remove("testp")
+			os.Remove("testp" + exeSuffix)
 			os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 		}()
 	}
@@ -747,8 +773,9 @@ func TestSIGPROF(t *testing.T) {
 	}
 
 	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo6.a", "./libgo6")
-	if out, err := cmd.CombinedOutput(); err != nil {
-		t.Logf("%s", out)
+	out, err := cmd.CombinedOutput()
+	t.Logf("%v\n%s", cmd.Args, out)
+	if err != nil {
 		t.Fatal(err)
 	}
 	checkLineComments(t, "libgo6.h")
@@ -757,15 +784,18 @@ func TestSIGPROF(t *testing.T) {
 	if runtime.Compiler == "gccgo" {
 		ccArgs = append(ccArgs, "-lgo")
 	}
-	if out, err := exec.Command(ccArgs[0], ccArgs[1:]...).CombinedOutput(); err != nil {
-		t.Logf("%s", out)
+	out, err = exec.Command(ccArgs[0], ccArgs[1:]...).CombinedOutput()
+	t.Logf("%v\n%s", ccArgs, out)
+	if err != nil {
 		t.Fatal(err)
 	}
+	checkIsExecutable(t, "./testp6"+exeSuffix)
 
 	argv := cmdToRun("./testp6")
 	cmd = exec.Command(argv[0], argv[1:]...)
-	if out, err := cmd.CombinedOutput(); err != nil {
-		t.Logf("%s", out)
+	out, err = cmd.CombinedOutput()
+	t.Logf("%v\n%s", argv, out)
+	if err != nil {
 		t.Fatal(err)
 	}
 }
@@ -788,9 +818,8 @@ func TestCompileWithoutShared(t *testing.T) {
 	}
 
 	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-gcflags=-shared=false", "-o", "libgo2.a", "./libgo2")
-	t.Log(cmd.Args)
 	out, err := cmd.CombinedOutput()
-	t.Logf("%s", out)
+	t.Logf("%v\n%s", cmd.Args, out)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -804,23 +833,22 @@ func TestCompileWithoutShared(t *testing.T) {
 	if runtime.Compiler == "gccgo" {
 		ccArgs = append(ccArgs, "-lgo")
 	}
-	t.Log(ccArgs)
 	out, err = exec.Command(ccArgs[0], ccArgs[1:]...).CombinedOutput()
+	t.Logf("%v\n%s", ccArgs, out)
 
 	// If -no-pie unrecognized, try -nopie if this is possibly clang
 	if err != nil && bytes.Contains(out, []byte("unknown")) && !strings.Contains(cc[0], "gcc") {
 		ccArgs = append(cc, "-o", exe, "-nopie", "main5.c", "libgo2.a")
-		t.Log(ccArgs)
 		out, err = exec.Command(ccArgs[0], ccArgs[1:]...).CombinedOutput()
+		t.Logf("%v\n%s", ccArgs, out)
 	}
 
 	// Don't use either -no-pie or -nopie
 	if err != nil && bytes.Contains(out, []byte("unrecognized")) {
-		ccArgs := append(cc, "-o", exe, "main5.c", "libgo2.a")
-		t.Log(ccArgs)
+		ccArgs = append(cc, "-o", exe, "main5.c", "libgo2.a")
 		out, err = exec.Command(ccArgs[0], ccArgs[1:]...).CombinedOutput()
+		t.Logf("%v\n%s", ccArgs, out)
 	}
-	t.Logf("%s", out)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -829,17 +857,15 @@ func TestCompileWithoutShared(t *testing.T) {
 	}
 
 	binArgs := append(cmdToRun(exe), "1")
-	t.Log(binArgs)
 	out, err = exec.Command(binArgs[0], binArgs[1:]...).CombinedOutput()
-	t.Logf("%s", out)
+	t.Logf("%v\n%s", binArgs, out)
 	expectSignal(t, err, syscall.SIGSEGV)
 
 	// SIGPIPE is never forwarded on darwin. See golang.org/issue/33384.
 	if runtime.GOOS != "darwin" && runtime.GOOS != "ios" {
 		binArgs := append(cmdToRun(exe), "3")
-		t.Log(binArgs)
 		out, err = exec.Command(binArgs[0], binArgs[1:]...).CombinedOutput()
-		t.Logf("%s", out)
+		t.Logf("%v\n%s", binArgs, out)
 		expectSignal(t, err, syscall.SIGPIPE)
 	}
 }
@@ -894,8 +920,9 @@ func TestManyCalls(t *testing.T) {
 	}
 
 	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo7.a", "./libgo7")
-	if out, err := cmd.CombinedOutput(); err != nil {
-		t.Logf("%s", out)
+	out, err := cmd.CombinedOutput()
+	t.Logf("%v\n%s", cmd.Args, out)
+	if err != nil {
 		t.Fatal(err)
 	}
 	checkLineComments(t, "libgo7.h")
@@ -904,16 +931,18 @@ func TestManyCalls(t *testing.T) {
 	if runtime.Compiler == "gccgo" {
 		ccArgs = append(ccArgs, "-lgo")
 	}
-	if out, err := exec.Command(ccArgs[0], ccArgs[1:]...).CombinedOutput(); err != nil {
-		t.Logf("%s", out)
+	out, err = exec.Command(ccArgs[0], ccArgs[1:]...).CombinedOutput()
+	t.Logf("%v\n%s", ccArgs, out)
+	if err != nil {
 		t.Fatal(err)
 	}
+	checkIsExecutable(t, "./testp7"+exeSuffix)
 
 	argv := cmdToRun("./testp7")
 	cmd = exec.Command(argv[0], argv[1:]...)
-	var sb strings.Builder
-	cmd.Stdout = &sb
-	cmd.Stderr = &sb
+	sb := new(strings.Builder)
+	cmd.Stdout = sb
+	cmd.Stderr = sb
 	if err := cmd.Start(); err != nil {
 		t.Fatal(err)
 	}
@@ -926,8 +955,9 @@ func TestManyCalls(t *testing.T) {
 	)
 	defer timer.Stop()
 
-	if err := cmd.Wait(); err != nil {
-		t.Log(sb.String())
+	err = cmd.Wait()
+	t.Logf("%v\n%s", cmd.Args, sb)
+	if err != nil {
 		t.Error(err)
 	}
 }
@@ -949,23 +979,26 @@ func TestPreemption(t *testing.T) {
 	}
 
 	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo8.a", "./libgo8")
-	if out, err := cmd.CombinedOutput(); err != nil {
-		t.Logf("%s", out)
+	out, err := cmd.CombinedOutput()
+	t.Logf("%v\n%s", cmd.Args, out)
+	if err != nil {
 		t.Fatal(err)
 	}
 	checkLineComments(t, "libgo8.h")
 
 	ccArgs := append(cc, "-o", "testp8"+exeSuffix, "main8.c", "libgo8.a")
-	if out, err := exec.Command(ccArgs[0], ccArgs[1:]...).CombinedOutput(); err != nil {
-		t.Logf("%s", out)
+	out, err = exec.Command(ccArgs[0], ccArgs[1:]...).CombinedOutput()
+	t.Logf("%v\n%s", ccArgs, out)
+	if err != nil {
 		t.Fatal(err)
 	}
+	checkIsExecutable(t, "./testp8"+exeSuffix)
 
 	argv := cmdToRun("./testp8")
 	cmd = exec.Command(argv[0], argv[1:]...)
-	var sb strings.Builder
-	cmd.Stdout = &sb
-	cmd.Stderr = &sb
+	sb := new(strings.Builder)
+	cmd.Stdout = sb
+	cmd.Stderr = sb
 	if err := cmd.Start(); err != nil {
 		t.Fatal(err)
 	}
@@ -978,8 +1011,9 @@ func TestPreemption(t *testing.T) {
 	)
 	defer timer.Stop()
 
-	if err := cmd.Wait(); err != nil {
-		t.Log(sb.String())
+	err = cmd.Wait()
+	t.Logf("%v\n%s", cmd.Args, sb)
+	if err != nil {
 		t.Error(err)
 	}
 }