From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1944) id 8491B3857B9A; Fri, 5 Aug 2022 19:35:50 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8491B3857B9A Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Szabolcs Nagy To: glibc-cvs@sourceware.org Subject: [glibc/arm/morello/main] cheri: malloc: fix alignment logic in obstack X-Act-Checkin: glibc X-Git-Author: Szabolcs Nagy X-Git-Refname: refs/heads/arm/morello/main X-Git-Oldrev: 84068c087ba210a694aa656f6c873f4d7daa84d0 X-Git-Newrev: 6af67120e8d889f1595d9d066d7798a8fba8a9db Message-Id: <20220805193550.8491B3857B9A@sourceware.org> Date: Fri, 5 Aug 2022 19:35:50 +0000 (GMT) X-BeenThere: glibc-cvs@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Glibc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 Aug 2022 19:35:50 -0000 https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=6af67120e8d889f1595d9d066d7798a8fba8a9db commit 6af67120e8d889f1595d9d066d7798a8fba8a9db Author: Szabolcs Nagy Date: Wed Mar 16 14:07:04 2022 +0000 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. Diff: --- malloc/obstack.h | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) diff --git a/malloc/obstack.h b/malloc/obstack.h index 4b01cdfe4d..1cf18e5464 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