all: final cleanups in preparation for release

src/util/xspan_impl.h

@@ -206,6 +206,16 @@ struct XSpanInternalDummyArg {
 
 XSPAN_NAMESPACE_END
 
+// poison a pointer: point to a non-null invalid address
+// - resulting pointer should crash on dereference
+// - this should be efficient (so no mmap() guard page etc.)
+// - this should play nice with runtime checkers like ASAN, valgrind, etc.
+// - this should play nice with static analyzers like clang-tidy
+static forceinline void *XSPAN_GET_POISON_VOID_PTR() {
+    // return (void *) (upx_uintptr_t) 16; // NOLINT(performance-no-int-to-ptr)
+    return (void *) 16;
+}
+
 #ifndef XSPAN_DELETED_FUNCTION
 #define XSPAN_DELETED_FUNCTION = delete
 #endif