Re: [PATCH 3/4] configure.ac: Add a --disable-lto configure option

On 09.07.2014 03:13, Bryce W. Harrington wrote:
> Link-Time Optimization seems to be stable enough with gcc 4.8 and 4.9,
> but has proven to be an issue in the past for many cairo users (webkit,
> efl, ubuntu, opensuse, gentoo, arch...) who carry patches to disable it.
> 
> Gentoo's patch[1] adds a --disable-lto option to leave it enabled by
> default but give users the ability to work around lto related build
> problems (c.f. fdo #77060).
> 
> 1: sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/x11-libs/cairo/files/cairo-1.12.16-lto-optional.patch
> 
> Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=60852
> Signed-off-by: Bryce Harrington <[email protected]>

I'm not really happy with the unclear authorship of this patch, but it's simple
enough that I am going to look the other way.

Reviewed-by: Uli Schlachter <[email protected]>

> ---
>  build/configure.ac.warnings |   15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/build/configure.ac.warnings b/build/configure.ac.warnings
> index f984eb2..a72d948 100644
> --- a/build/configure.ac.warnings
> +++ b/build/configure.ac.warnings
> @@ -38,13 +38,18 @@ dnl options.  Namely, the following:
>  
>  dnl -flto working really needs a test link, not just a compile
>  
> -safe_MAYBE_WARN="$MAYBE_WARN"
> -MAYBE_WARN="$MAYBE_WARN -flto"
> -AC_TRY_LINK([],[
> +AC_ARG_ENABLE(lto,
> +  AS_HELP_STRING([--disable-lto],
> +                 [Do not try to use Link-Time Optimization]))
> +if test "x$enable_lto" != "xno"; then
> +   safe_MAYBE_WARN="$MAYBE_WARN"
> +   MAYBE_WARN="$MAYBE_WARN -flto"
> +   AC_TRY_LINK([],[
>  	int main(int argc, char **argv) { return 0; }
> -],[],[
> +   ],[],[
>  	MAYBE_WARN="$safe_MAYBE_WARN"
> -])
> +   ])
> +fi
>  
>  MAYBE_WARN="$MAYBE_WARN -fno-strict-aliasing -fno-common"
>  
> 


-- 
"Why make things difficult, when it is possible to make them cryptic
and totally illogical, with just a little bit more effort?" -- A. P. J.
-- 
cairo mailing list
[email protected]
http://lists.cairographics.org/mailman/listinfo/cairo