diff options
| author | Alan Modra <amodra@gmail.com> | 2021-09-02 09:05:05 +0930 |
|---|---|---|
| committer | Alan Modra <amodra@gmail.com> | 2021-09-22 17:14:17 +0930 |
| commit | b0321032658d875bee7584d8e3a8cbdd275c99d5 (patch) | |
| tree | 09434b749884e6286edfef2caddc5a6155367831 /include/obstack.h | |
| parent | a9b3c451be58f0fe660154323ace7ba72a4211ec (diff) | |
obstack.h __PTR_ALIGN vs. ubsan
Current ubsan complains on every use of __PTR_ALIGN (when ptrdiff_t is
as large as a pointer), due to making calculations relative to a NULL
pointer. This patch avoids the problem by extracting out and
simplifying __BPTR_ALIGN for the usual case. I've continued to use
ptrdiff_t here, where it might be better to throw away __BPTR_ALIGN
entirely and just assume uintptr_t exists.
* obstack.h (__PTR_ALIGN): Expand and simplify __BPTR_ALIGN
rather than calculating relative to a NULL pointer.
Diffstat (limited to 'include/obstack.h')
| -rw-r--r-- | include/obstack.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/obstack.h b/include/obstack.h index a6eb6c95587..0d8746f835b 100644 --- a/include/obstack.h +++ b/include/obstack.h @@ -137,9 +137,9 @@ relative to B. Otherwise, use the faster strategy of computing the alignment relative to 0. */ -#define __PTR_ALIGN(B, P, A) \ - __BPTR_ALIGN (sizeof (ptrdiff_t) < sizeof (void *) ? (B) : (char *) 0, \ - P, A) +#define __PTR_ALIGN(B, P, A) \ + (sizeof (ptrdiff_t) < sizeof (void *) ? __BPTR_ALIGN (B, P, A) \ + : (char *) (((ptrdiff_t) (P) + (A)) & ~(A))) #ifndef __attribute_pure__ # if defined __GNUC_MINOR__ && __GNUC__ * 1000 + __GNUC_MINOR__ >= 2096 |