Re: [PATCH] misc: only build with lto if explicitly enabled

[Dave Chinner <david@fromorbit.com>]

On Fri, Oct 26, 2018 at 04:25:38PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Change the LTO default to off from probe because it wastes build time on
> developer machines.  Anyone who really wants it for release builds or
> whatever can still turn it on.

Build time is not the problem. Making the resultant binary
completely unusable with gdb and hence undebuggable is the real
problem with LTO.

> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  configure.ac |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index 44a4b3a8..f8f29c07 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -109,8 +109,8 @@ AC_ARG_ENABLE(threadsan,
>  AC_SUBST(enable_threadsan)
>  
>  AC_ARG_ENABLE(lto,
> -[ --enable-lto=[yes/no]      Enable link time optimization (LTO) [default=probe]],,
> -	enable_lto=probe)
> +[ --enable-lto=[yes/no]      Enable link time optimization (LTO) [default=no]],,
> +	enable_lto=no)

Looks good.

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com