Re: [PATCH, libjava/classpath]: Fix overriding recipe for target 'gjdoc' build warning

[Andrew Haley <aph@redhat.com>]

On 08/20/2015 03:57 PM, Andrew Hughes wrote:
> ----- Original Message -----
>> On 20/08/15 09:24, Matthias Klose wrote:
>>> On 08/20/2015 06:36 AM, Tom Tromey wrote:
>>>> Andrew> No, it isn't. It's still a necessity for initial bootstrapping of
>>>> Andrew> OpenJDK/IcedTea.
>>>>
>>>> Andrew Haley said the opposite here:
>>>>
>>>> https://gcc.gnu.org/ml/gcc-patches/2015-08/msg00537.html
>>>
>>> if you need bootstrapping OpenJDK 6 or OpenJDK 7, then having gcj
>>> available for the target platform is required. Starting with OpenJDK
>>> 8 you should be able to cross build OpenJDK 8 with an OpenJDK 8
>>> available on the cross platform.  It might be possible to cross
>>> build older OpenJDK versions, but this usually is painful.
>>
>> Sure, but we don't need GCJ going forward.  I don't think that there
>> are any new platforms to which OpenJDK has not been ported which will
>> require GCJ to bootstrap.  And even if there are, anybody who needs to
>> do that can (and, indeed, should) use an earlier version of GCJ.  It's
>> not going to go away; it will always be in the GCC repos.  And because
>> newer versions of GCC may break GCJ (and maybe OpenJDK) it makes more
>> sense to use an old GCC/GCJ for the bootstrapping of an old OpenJDK.
> 
> I don't see how we don't at present. How else do you solve the
> chicken-and-egg situation of needing a JDK to build a JDK? I don't
> see crossing your fingers and hoping there's a binary around
> somewhere as a very sustainable system.

That's what we do with GCC, binutils, etc: we bootstrap.

> From a personal point of view, I need gcj to make sure each new
> IcedTea 1.x and 2.x release bootstraps.

Sure, but all that does is test that the GCJ bootstrap still works.
And it's probably the only serious use of GCJ left.

> I don't plan to hold my system GCC at GCC 5 for the next decade or
> however long we plan to support IcedTea 2.x / OpenJDK 7. It's also
> still noticeably faster building with a native ecj than OpenJDK's
> javac.  It would cause me and others a lot of pain to remove gcj at
> this point. What exactly is the reason to do so, other than some
> sudden whim?

It's not a sudden whim: it's something we've been discussing for years.
The only reason GCJ is still alive is that I committed to keep it
going while we still needed it boot bootstrap OpenJDK.  Maintaining
GCJ in GCC is a significant cost, and GCJ has reached the end of its
natural life.  Classpath is substantially unmaintained, and GCJ
doesn't support any recent versions of Java.

Andrew.