misc/cgo/testsanitizers: determine compiler version for tsan tests on ppc64le

Some tests in misc/cgo/testsanitizers had been disabled on ppc64le
until recently, due to an intermittent error in the tsan tests,
with the goal of trying to understand the failure.

After further investigation, I found that the code for tsan within
gcc does not work consistently when ASLR is enabled on ppc64le. A
fix for that problem was integrated in gcc 9.

This adds a check to testsanitizers to determine the gcc compiler
version on ppc64le and skip the test if the version is too old.

A similar check is needed for asan too.

Updates #54645

Change-Id: I70717d1aa9e967cf1e871566e72b3862b91fea3f
Reviewed-on: https://go-review.googlesource.com/c/go/+/425355
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Archana Ravindar <aravind5@in.ibm.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>

misc/cgo/testsanitizers/asan_test.go

@@ -27,8 +27,8 @@ func TestASAN(t *testing.T) {
 	// -asan option must use a compatible version of ASan library, which requires that
 	// the gcc version is not less than 7 and the clang version is not less than 9,
 	// otherwise a segmentation fault will occur.
-	if !compilerRequiredAsanVersion() {
+	if !compilerRequiredAsanVersion(goos, goarch) {
-		t.Skipf("skipping: too old version of compiler")
+		t.Skipf("skipping on %s/%s: too old version of compiler", goos, goarch)
 	}
 
 	t.Parallel()

misc/cgo/testsanitizers/cc_test.go

@@ -252,14 +252,30 @@ func compilerSupportsLocation() bool {
 	}
 }
 
+// compilerRequiredTsanVersion reports whether the compiler is the version required by Tsan.
+// Only restrictions for ppc64le are known; otherwise return true.
+func compilerRequiredTsanVersion(goos, goarch string) bool {
+	compiler, err := compilerVersion()
+	if err != nil {
+		return false
+	}
+	if compiler.name == "gcc" && goarch == "ppc64le" {
+		return compiler.major >= 9
+	}
+	return true
+}
+
 // compilerRequiredAsanVersion reports whether the compiler is the version required by Asan.
-func compilerRequiredAsanVersion() bool {
+func compilerRequiredAsanVersion(goos, goarch string) bool {
 	compiler, err := compilerVersion()
 	if err != nil {
 		return false
 	}
 	switch compiler.name {
 	case "gcc":
+		if goarch == "ppc64le" {
+			return compiler.major >= 9
+		}
 		return compiler.major >= 7
 	case "clang":
 		return compiler.major >= 9

misc/cgo/testsanitizers/cshared_test.go

@@ -52,6 +52,11 @@ func TestShared(t *testing.T) {
 			t.Logf("skipping %s test on %s/%s; -msan option is not supported.", name, GOOS, GOARCH)
 			continue
 		}
+		if tc.sanitizer == "thread" && !compilerRequiredTsanVersion(GOOS, GOARCH) {
+			t.Logf("skipping %s test on %s/%s; compiler version too old for -tsan.", name, GOOS, GOARCH)
+			continue
+		}
+
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()
 			config := configure(tc.sanitizer)

misc/cgo/testsanitizers/tsan_test.go

@@ -10,6 +10,19 @@ import (
 )
 
 func TestTSAN(t *testing.T) {
+	goos, err := goEnv("GOOS")
+	if err != nil {
+		t.Fatal(err)
+	}
+	goarch, err := goEnv("GOARCH")
+	if err != nil {
+		t.Fatal(err)
+	}
+	// The msan tests require support for the -msan option.
+	if !compilerRequiredTsanVersion(goos, goarch) {
+		t.Skipf("skipping on %s/%s; compiler version for -tsan option is too old.", goos, goarch)
+	}
+
 	t.Parallel()
 	requireOvercommit(t)
 	config := configure("thread")