From cd2b55e536dc806f9358f71db438dd9c246cdb14 Mon Sep 17 00:00:00 2001 From: Jonas Pfeil Date: Wed, 1 Mar 2017 18:11:10 +0100 Subject: [PATCH] ralloc: Make sure ralloc() allocations match malloc()'s alignment. MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The header of ralloc needs to be aligned, because the compiler assumes that malloc returns will be aligned to 8/16 bytes depending on the platform, leading to degraded performance or alignment faults with ralloc. Fixes SIGBUS on Raspberry Pi at high optimization levels. This patch is not perfect for MSVC, as maybe in the future the alignment for the most demanding data type might change to more than 8. v2: Commit message reword/typo fix, and add a bigger explanation in the code (by anholt) Signed-off-by: Jonas Pfeil Reviewed-by: Matt Turner Reviewed-by: Marek Olšák Cc: mesa-stable@lists.freedesktop.org --- src/util/ralloc.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/src/util/ralloc.c b/src/util/ralloc.c index d5cc167..03283de 100644 --- a/src/util/ralloc.c +++ b/src/util/ralloc.c @@ -51,7 +51,18 @@ _CRTIMP int _vscprintf(const char *format, va_list argptr); #define CANARY 0x5A1106 -struct ralloc_header +/* Align the header's size so that ralloc() allocations will return with the + * same alignment as a libc malloc would have (8 on 32-bit GLIBC, 16 on + * 64-bit), avoiding performance penalities on x86 and alignment faults on + * ARM. + */ +struct +#ifdef _MSC_VER + __declspec(align(8)) +#else + __attribute__((aligned)) +#endif + ralloc_header { #ifdef DEBUG /* A canary value used to determine whether a pointer is ralloc'd. */ -- 2.7.4