Messages in this thread | | | Date | Fri, 10 Apr 2015 21:23:19 +0200 | From | Daniel Borkmann <> | Subject | Re: [PATCH] x86: Align jump targets to 1 byte boundaries |
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On 04/10/2015 02:50 PM, Denys Vlasenko wrote: ... > New-ish versions of gcc allow people to specify optimization > options per function: > > https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function-Attributes > > optimize > The optimize attribute is used to specify that a function is to be compiled > with different optimization options than specified on the command line. > Arguments can either be numbers or strings. Numbers are assumed to be an > optimization level. Strings that begin with O are assumed to be an > optimization option, while other options are assumed to be used with > a -f prefix. > > How about not aligning code by default, and using > > #define hot_func __attribute__((optimize("O2","align-functions=16","align-jumps=16")))
I stumbled over that some time ago in a different context. Apparently, that's being considered broken by gcc folks [1]. ;)
[1] http://gcc.gnu.org/ml/gcc/2012-07/msg00211.html
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