1 files changed, 38 insertions, 0 deletions
diff --git a/test/msan/wcsncpy.cc b/test/msan/wcsncpy.cc
new file mode 100644
index 0000000000000..f582c37b7aab4
--- /dev/null
+++ b/test/msan/wcsncpy.cc
@@ -0,0 +1,38 @@
+// RUN: %clangxx_msan -fsanitize-memory-track-origins -O0 %s -o %t && not %run %t >%t.out 2>&1
+// RUN: FileCheck %s < %t.out && FileCheck %s < %t.out
+
+#include <assert.h>
+#include <wchar.h>
+
+#include <sanitizer/msan_interface.h>
+
+int main() {
+  const wchar_t *s = L"abc";
+  assert(wcslen(s) == 3);
+
+  wchar_t s2[5];
+  assert(wcsncpy(s2, s, 3) == s2);
+  assert(__msan_test_shadow(&s2, 5 * sizeof(wchar_t)) == 3 * sizeof(wchar_t));
+  assert(wcsncpy(s2, s, 5) == s2);
+  assert(__msan_test_shadow(&s2, 5 * sizeof(wchar_t)) == -1);
+
+  wchar_t s3[5];
+  assert(wcsncpy(s3, s, 2) == s3);
+  assert(__msan_test_shadow(&s3, 5 * sizeof(wchar_t)) == 2 * sizeof(wchar_t));
+
+  __msan_allocated_memory(&s2[1], sizeof(wchar_t));
+  wchar_t s4[5];
+  assert(wcsncpy(s4, s2, 3) == s4);
+  __msan_check_mem_is_initialized(&s4, sizeof(s4));
+}
+// CHECK:  Uninitialized bytes in __msan_check_mem_is_initialized
+// CHECK:  WARNING: MemorySanitizer: use-of-uninitialized-value
+// CHECK:    in main {{.*}}wcsncpy.cc:26
+
+// CHECK:  Uninitialized value was stored to memory at
+// CHECK:    in {{[^\s]*}}wcsncpy
+// CHECK:    in main {{.*}}wcsncpy.cc:25
+
+// CHECK:  Memory was marked as uninitialized
+// CHECK:    in __msan_allocated_memory
+// CHECK:    in main {{.*}}wcsncpy.cc:23