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authorGregory P. Smith <greg@krypto.org>2012-12-11 02:32:53 (GMT)
committerGregory P. Smith <greg@krypto.org>2012-12-11 02:32:53 (GMT)
commitc2176e46d797c8aea60cdcd2ddf44f6bb88394b4 (patch)
tree5c4d898d216d25af779db557da42e1fccbb31e6d /Objects/unicodeobject.c
parentc0dd80e439bff4bd7cd9acc34ae023b4e8adf4aa (diff)
parent27cbcd6241d787b5e99c6ed05ec8377051f397aa (diff)
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Fix the internals of our hash functions to used unsigned values during hash
computation as the overflow behavior of signed integers is undefined. NOTE: This change is smaller compared to 3.2 as much of this cleanup had already been done. I added the comment that my change in 3.2 added so that the code would match up. Otherwise this just adds or synchronizes appropriate UL designations on some constants to be pedantic. 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 60a74d6..0b9d652 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -11008,7 +11008,7 @@ static Py_hash_t
unicode_hash(PyObject *self)
{
Py_ssize_t len;
- Py_uhash_t x;
+ Py_uhash_t x; /* Unsigned for defined overflow behavior. */
#ifdef Py_DEBUG
assert(_Py_HashSecret_Initialized);