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author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2022-03-16 14:07:04 +0000 |
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committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2022-08-05 19:45:19 +0100 |
commit | 6af67120e8d889f1595d9d066d7798a8fba8a9db (patch) | |
tree | a1b168a5ff9b882465ff4c526504107d2c14aa51 | |
parent | 84068c087ba210a694aa656f6c873f4d7daa84d0 (diff) | |
download | glibc-6af67120e8d889f1595d9d066d7798a8fba8a9db.zip glibc-6af67120e8d889f1595d9d066d7798a8fba8a9db.tar.gz glibc-6af67120e8d889f1595d9d066d7798a8fba8a9db.tar.bz2 |
cheri: malloc: fix alignment logic in obstack
If sizeof(ptrdiff_t) < sizeof(void*) the alignment logic was wrong
(incorrectly assumed that base was already sufficiently aligned).
Use more robust alignment logic: this one should work on any target.
Note: this is an installed header so it must be namespace clean and
portable.
-rw-r--r-- | malloc/obstack.h | 19 |
1 files changed, 3 insertions, 16 deletions
diff --git a/malloc/obstack.h b/malloc/obstack.h index 4b01cdf..1cf18e5 100644 --- a/malloc/obstack.h +++ b/malloc/obstack.h @@ -116,22 +116,9 @@ # define PTR_INT_TYPE ptrdiff_t #endif -/* If B is the base of an object addressed by P, return the result of - aligning P to the next multiple of A + 1. B and P must be of type - char *. A + 1 must be a power of 2. */ - -#define __BPTR_ALIGN(B, P, A) ((B) + (((P) - (B) + (A)) & ~(A))) - -/* Similar to _BPTR_ALIGN (B, P, A), except optimize the common case - where pointers can be converted to integers, aligned as integers, - and converted back again. If PTR_INT_TYPE is narrower than a - pointer (e.g., the AS/400), play it safe and compute the alignment - relative to B. Otherwise, use the faster strategy of computing the - alignment relative to 0. */ - -#define __PTR_ALIGN(B, P, A) \ - __BPTR_ALIGN (sizeof (PTR_INT_TYPE) < sizeof (void *) ? (B) : (char *) 0, \ - P, A) +/* Align P to the next multiple of A + 1, where A + 1 is a power of 2, + A fits into unsigned long and P has type char *. */ +#define __PTR_ALIGN(B, P, A) ((P) + (-(unsigned long)(P) & (A))) #include <string.h> |