sanitizer_common: add test that calls wcslen

[thurston]

Summary

This is a very simple test that calls wsclen. There are currently no other HWASan tests that call wsclen, which is why the wcslen interceptor issue (triggered by https://reviews.llvm.org/D150708 and fixed in https://reviews.llvm.org/D150909) was only detected by stage2/hwasan check on the buildbots. With this test, the issue would have been caught by stage1 check-sanitizer, with a more obvious diagnosis.

[vitalybuka]

compiler-rt/test/sanitizer_common/TestCases/wcslen_test.c

2

-O0 to make sure compiler will not optimize this out?

[thurston]

Add -O0 flag, per Vitaly's suggestion

[thurston]

compiler-rt/test/sanitizer_common/TestCases/wcslen_test.c

2

Done

compiler-rt/test/sanitizer_common/TestCases/wcslen_test.c

+// RUN: %clang %s -O0 -o %t && %run %t 2>&1
+
+#include <assert.h>
+#include <wchar.h>
+
+int main(int argc, char **argv) {
+  wchar_t x[] = L"Hello World!";
+  assert(wcslen(x) == 12);
+  return 0;
+}