[PINGv2][PATCH] Asan optimization for aligned accesses.

Marat Zakirov m.zakirov@samsung.com
Tue Sep 16 15:00:00 GMT 2014


On 09/10/2014 04:30 PM, Marat Zakirov wrote:
> On 09/02/2014 07:09 PM, Marat Zakirov wrote:
>>> Hi all!
>>>
>>> Here's a simple optimization patch for Asan. It stores alignment 
>>> information into ASAN_CHECK which is then extracted by sanopt to 
>>> reduce number of "and 0x7" instructions for sufficiently aligned 
>>> accesses. I checked it on linux kernel by comparing results of 
>>> objdump -d -j .text vmlinux | grep "and.*0x7," for optimized and 
>>> regular cases. It eliminates 12% of and 0x7's.
>>>
>>> No regressions. Sanitized GCC was successfully Asan-bootstrapped. No 
>>> false positives were found in kernel.
>>>
>>> --Marat
>>>
>

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