Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

external/llvm-project/compiler-rt/test/msan/cxa_atexit.cc

@@ -0,0 +1,28 @@
+// RUN: %clangxx_msan -O0 %s -o %t && %run %t %p
+
+// PR17377: C++ module destructors get stale argument shadow.
+
+#include <stdio.h>
+#include <stdlib.h>
+class A {
+public:
+  // This destructor get stale argument shadow left from the call to f().
+  ~A() {
+    if (this)
+      exit(0);
+  }
+};
+
+A a;
+
+__attribute__((noinline))
+void f(long x) {
+}
+
+int main(void) {
+  long  x;
+  long * volatile p = &x;
+  // This call poisons TLS shadow for the first function argument.
+  f(*p);
+  return 0;
+}