Fix the internals of our hash functions to used unsigned values during hash
computation as the overflow behavior of signed integers is undefined.
In practice we require compiling everything with -fwrapv which forces overflow
to be defined as twos compliment but this keeps the code cleaner for checkers
or in the case where someone has compiled it without -fwrapv or their
compiler's equivalent.
Found by Clang trunk's Undefined Behavior Sanitizer (UBSan).
Cleanup only - no functionality or hash values change.
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 796e400..ef3a5a1 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -873,7 +873,7 @@
{
register Py_ssize_t len;
register unsigned char *p;
- register Py_hash_t x;
+ register Py_uhash_t x; /* Unsigned for defined overflow behavior. */
#ifdef Py_DEBUG
assert(_Py_HashSecret_Initialized);