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| author | Alan Modra <amodra@gmail.com> | 2021-09-02 09:05:05 +0930 |
|---|---|---|
| committer | Alan Modra <amodra@gmail.com> | 2021-09-02 13:48:21 +0930 |
| commit | 76aa354424729aafdabdf4929aa9751c6fdee081 (patch) | |
| tree | 6f4158b08147ef89e98315304cf5bc4d2f31c013 /include/obstack.h | |
| parent | c79332d2d13936dfc029a935a9b9823ca0d575c3 (diff) | |
| download | gdb-76aa354424729aafdabdf4929aa9751c6fdee081.zip gdb-76aa354424729aafdabdf4929aa9751c6fdee081.tar.gz gdb-76aa354424729aafdabdf4929aa9751c6fdee081.tar.bz2 | |
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 a6eb6c9..0d8746f 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 |