[Mesa-dev] [PATCH] util/disk_cache: fix zlib linking with LTO build

[Matt Turner]

On Sat, Mar 11, 2017 at 7:31 AM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> On 10 March 2017 at 13:36, Steven Newbury <steve at snewbury.org.uk> wrote:
>> On Fri, 2017-03-10 at 12:11 +0000, Emil Velikov wrote:
>>> On 9 March 2017 at 14:39, Steven Newbury <steve at snewbury.org.uk>
>>> wrote:
>>> > Introduction of zlib compression for the shader cache means
>>> > zlib needs to be explicitly linked to libOSMesa and libstandalone
>>> > otherwise build fails when LTO is used.
>>> > ---
>>>
>>> How exactly are you doing the LTO build ?
>> I build everything LTO, except for a short blacklist where
>> unsupportable.  Specifically, on this system my global *FLAGS contain
>> "-flto=8 -fuse-linker-plugin".  I have the lto linker plugin symlinked
>> into "/usr/$CHOST/binutils-bin/lib/bfd-plugins/".
>>
>> I also have have the following env vars set to ensure they are called
>> with the LTO plugin:
>> AR="gcc-ar"
>> NM="gcc-nm"
>> RANLIB="gcc-ranlib"
>>
> One should not need these. Have you checked that the issue is
> reproducible w/o them ?

I think they are necessary

https://gcc.gnu.org/ml/gcc-help/2012-03/msg00100.html

(though I don't know under which circumstances precisely)

FWIW, I agree that this patch looks like a hack.