testsanitizers: check that tsan program runs, skip tsan10 on gcc

Check not only that a tsan program can be built, but also that it runs.
This fails with some installations of GCC 7.

Skip the tsan10 program when using GCC, as it reportedly hangs.

This is a patch to help people build 1.9; we may be able to do a
better fix for 1.10.

Updates #21196

Change-Id: Icd1ffbd018dc65a97ff45cab1264b9b0c7fa0ab2
Reviewed-on: https://go-review.googlesource.com/52790
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

misc/cgo/testsanitizers/test.bash

@@ -163,6 +163,9 @@ if test "$tsan" = "yes"; then
 	cat ${TMPDIR}/testsanitizers$$.err
 	echo "skipping tsan tests: -fsanitizer=thread build failed"
 	tsan=no
+    elif ! ${TMPDIR}/testsanitizers$$ 2>&1; then
+	echo "skipping tsan tests: running tsan program failed"
+	tsan=no
     fi
     rm -f ${TMPDIR}/testsanitizers$$*
 fi
@@ -196,8 +199,10 @@ if test "$tsan" = "yes"; then
     # These tests are only reliable using clang or GCC version 7 or later.
     # Otherwise runtime/cgo/libcgo.h can't tell whether TSAN is in use.
     ok=false
+    clang=false
     if ${CC} --version | grep clang >/dev/null 2>&1; then
 	ok=true
+	clang=true
     else
 	ver=$($CC -dumpversion)
 	major=$(echo $ver | sed -e 's/\([0-9]*\).*/\1/')
@@ -213,7 +218,12 @@ if test "$tsan" = "yes"; then
 	testtsan tsan5.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
 	testtsan tsan6.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
 	testtsan tsan7.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
+
+	# tsan10 reportedly hangs when built with GCC: issue #21196.
+	if test "$clang" = "true"; then
 	    testtsan tsan10.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
+	fi
+
 	testtsan tsan11.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
 	testtsan tsan12.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"