To: Tom Lane <tgl@sss.pgh.pa.us>, Daniel Black <daniel.black@au1.ibm.com>
References: <773008e7-db08-a525-c887-de9aee60fdce@au.ibm.com>
 <15598.1473300729@sss.pgh.pa.us>
From: Andrew Dunstan <andrew@dunslane.net>
Message-ID: <dba20851-2037-9806-f424-c94f3493b39e@dunslane.net>
Date: Thu, 8 Sep 2016 09:18:38 -0400
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Subject: Re: [Pgbuildfarm-members] new build members
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On 09/07/2016 10:12 PM, Tom Lane wrote:
> Daniel Black <daniel.black@au1.ibm.com> writes:
>> I've configured a bunch of builds to add to the build farm. The list is:
> Hi Daniel!  Thanks for bringing all those new critters online.
> However, may I suggest that the ccache+clang ones would be a lot more
> useful if you added this to their configuration:
>
>      build_env =>{
>
> +        # needed to make ccache play nice with clang
> +        CCACHE_CPP2 => '1',
>
> Lack of this option is what's causing a lot of those useless warnings
> (it has to do with clang being fed preprocessor output, which triggers
> some of its more dubious warning heuristics).  I think this has become
> the default behavior as of ccache 3.3, but in older versions you gotta
> ask for it.
>
> As an example of the importance of this,
> http://buildfarm.postgresql.org/cgi-bin/show_stage_log.pl?nm=devario&dt=2016-09-08%2000%3A44%3A53&stg=make
> contains something north of 1000 warnings, most of which are entirely
> bogus.  Makes it hard to see if there are any that are meaningful.


As of ccache version 3.3.1 this is apparently the default - see 
<https://ccache.samba.org/manual.html>

I guess I should put it in the sample config file to cater for older 
versions (e.g. my Fedora machine has 3.2.3 where it is apparently not 
the default).


cheers

andrew