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authorGregory P. Smith <greg@krypto.org>2012-12-10 18:15:46 -0800
committerGregory P. Smith <greg@krypto.org>2012-12-10 18:15:46 -0800
commit27cbcd6241d787b5e99c6ed05ec8377051f397aa (patch)
tree02fe4460f5a52993a36a9aa575397f9001700ae1 /Objects/unicodeobject.c
parent90555d0f0d0b8e4ffbbb37ba12a8e43020ad1e98 (diff)
downloadcpython-git-27cbcd6241d787b5e99c6ed05ec8377051f397aa.tar.gz
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.
Diffstat (limited to 'Objects/unicodeobject.c')
-rw-r--r--Objects/unicodeobject.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 565d298270..bb45b20b90 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -7686,7 +7686,7 @@ unicode_hash(PyUnicodeObject *self)
{
Py_ssize_t len;
Py_UNICODE *p;
- Py_hash_t x;
+ Py_uhash_t x; /* Unsigned for defined overflow behavior. */
#ifdef Py_DEBUG
assert(_Py_HashSecret_Initialized);