From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1944) id 24A8D3854170; Wed, 26 Oct 2022 15:11:33 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 24A8D3854170 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1666797103; bh=/sozpp7XH9YxPA4Zk+x+NKTzk28a026DZC1nuPk0eBk=; h=From:To:Subject:Date:From; b=s7XQqO+9TBoJ4gzq6csSUv7KO8avv4vHaW+nK0uY/ZS+wJ6+XX/eSFTCwkOgPY9ur DGw0CdW2HSUjcOpGpyr5N8Kse+ubC60lRaIMKLFO3GxWx5ch9iGwjjNBvsQToGl93m JbjO83OVvuEyFNHv1jGl6x2X8AwLq8AL4x9AnGGw= 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: 5a25980484b50497567c2842034a6015f7b55222 X-Git-Newrev: a2305153c665db237f063efee5b25303cb4e6899 Message-Id: <20221026151143.24A8D3854170@sourceware.org> Date: Wed, 26 Oct 2022 15:11:33 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=a2305153c665db237f063efee5b25303cb4e6899 commit a2305153c665db237f063efee5b25303cb4e6899 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