RFR: JDK-8027584 disable ccache by default

[Steven R. Loomis]

Filed: https://bugs.openjdk.java.net/browse/JDK-8065791

On 11/13/2014 10:59 PM, Steven R. Loomis wrote:
> Late to the party, but please note that the README-builds.html *still*
> says that  ccache is great and you should install it. Doesn't mention
> *anything* about ccache being off by default or `--enable-ccache` being
> needed.  In fact, configure actively disables ccache if you use a
> symlink to ccache for gcc.
>
> I'll file a ticket if need be to fix the docs. Bit by this change-
> ccache does much, much more good than harm for people who are making
> small changes to big projects. Not going to argue the default, but
> please keep the capability around if possible.
>
> -s (doing an overnight build to prime the ccache pump)
>
> On 1/28/2014 3:31 PM, Magnus Ihse Bursie wrote:
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8027584
>>
>> While ccache can be used to speed up recompilations, there are also
>> several issues with ccache. Old versions does not work correctly for
>> the jdk (we try to detect that). It does not work well on other
>> platforms than Linux; on Windows it does not work at all. Nevertheless
>> is ccache enabled on Windows if it is installed, which it apparently
>> tends to be with Cygwin nowadays, requiring the use of
>> --disable-ccache to avoid compilation failure.
>>
>> In many circumstances ccache also does not provide any performance
>> benefit. For instance, new compilations gets a performance hit. Only
>> recompilations benefits.
>>
>> It is better to turn this upside down. This patch makes ccache
>> disabled by default, on all platforms. If you want ccache and are sure
>> you are in a situation that benefits from it, then you can enable it.
>> It also removes the output in configure hinting that ccache should be
>> used.
>>
>> WebRev:
>> http://cr.openjdk.java.net/~ihse/JDK-8027584-disable-ccache-by-default/webrev.01
>>
>> /Magnus