RFR(M): 8046471: Use OPENJDK_TARGET_CPU_ARCH instead of legacy value for hotspot ARCH

[Mikael Vidstedt]

David,

Thanks for the feedback. Essentially the logic in the 
make/<os>/makefiles/defs.make files needs to recognize and deal with two 
different use cases:

1. ARCH being set by the JDK build system to the value of 
OPENJDK_TARGET_CPU_ARCH, or
2. no ARCH being set, in which case it needs to be populated - typically 
from uname

Since Solaris and bsd both override ARCH they do not care about 
OPENJDK_TARGET_CPU_ARCH and effectively always go through case 2.

Linux/x86 is where most of the difference (and confusion) is, but I 
think aix/ppc64 will also change slightly since the ARCH value will go 
from ppc64 to ppc. I've tried to make the relevant changes, but I cannot 
verify that they actually work. cc:ing the ppc-aix list in the hope that 
somebody can help out with that.


Summing it up, I have the following two webrevs:

top: 
http://cr.openjdk.java.net/~mikael/webrevs/8046471/webrev.01/top/webrev/
hotspot: 
http://cr.openjdk.java.net/~mikael/webrevs/8046471/webrev.01/hotspot/webrev/

With these changes I can build the normal platforms, but more 
verification is needed - esp. building hotspot only. Meanwhile feedback 
is much appreciated!

Cheers,
Mikael

On 2014-06-10 19:45, David Holmes wrote:
> Hi Mikael,
>
> This seems a reasonable proposal to me. We have an over-abundance of 
> "arch" variables and values, so reducing that is a good aim.
>
> As you note the main flow-on effect here is that the hotspot makefiles 
> have to be updated for the cases where OPENJDK_TARGET_CPU_ARCH and 
> OPENJDK_TARGET_CPU_LEGACY differ so that it still sets LIBARCH, 
> BUILDARCH, SRCARCH correctly. I think only x86 has that issue.
>
> Wouldn't it be nice if we could get rid of i386, i586, i686 etc both 
> internally and in the build artifacts and bundles!
>
> Cheers,
> David
>
> On 11/06/2014 10:11 AM, Mikael Vidstedt wrote:
>>
>> All,
>>
>> I need some feedback and comments on the below fix:
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8046471
>> Webrev:
>> http://cr.openjdk.java.net/~mikael/webrevs/8046471/webrev.00/webrev/
>>
>> Background:
>>
>> When configuring the hotspot build the build system sets up the ARCH
>> variable to reflect the target cpu. Currently the value is initialized
>> to OPENJDK_TARGET_CPU_LEGACY, which is the internal legacy cpu name. For
>> example, on x86 64-bit this is amd64 on linux (but x86_64 on mac). The
>> goal in the new (JDK) build system is to have the "legacy" value
>> gradually removed in favor of the other variables.
>>
>> Discussion:
>>
>> The two candidate variables to base ARCH on are as far as I can tell
>> OPENJDK_TARGET_CPU and OPENJDK_TARGET_CPU_ARCH. Of the two
>> OPENJDK_TARGET_CPU_ARCH is the more "stable" one, with a single, well
>> defined value per cpu family { arm, ppc, s390, sparc, x86 }. Together
>> with ARCH_DATA_MODEL/LP64 that information should be enough for the
>> Hotspot build system to do its thing. Note: ARCH is currently ignored on
>> solaris and bsd - it's overridden at the top of the respective
>> make/<os>/makefiles/defs.make files.
>>
>> Before I go too far with this though I'd like to get some feedback on
>> whether or not this is the right approach and what the exact value
>> should be. Depending on the outcome of that the Hotspot build system may
>> have to be updated for some platforms to support the new value(s).
>>
>> Thanks,
>> Mikael
>>