RFR 8202683: Minimal VM should build cleanly on 64-bit platforms

[Aleksey Shipilev]

On 05/06/2018 09:20 AM, David Holmes wrote:
> On 5/05/2018 9:26 PM, Aleksey Shipilev wrote:
>> RFE:
>>    https://bugs.openjdk.java.net/browse/JDK-8202683
>>
>> Fix:
>>    http://cr.openjdk.java.net/~shade/8202683/webrev.01/
>>
>> Minimal VM is targeted to 32-bit only, but hear me out. Recent build system changes, notably
>> conditional GC compilation, requires build/testing with some GCs disabled. Ultimately, we want
>> minimal VM to be buildable at all times. Today, we need to cross-compile to x86_32 to verify that,
>> but with this change, we can build minimal on x86_64, thus simplifying our day-to-day jobs. The
>> change itself generates jvm.cfg for minimal VM properly on both bitnesses.
> 
> Is 64-bit client VM now able to be built routinely?

As far as I understand, the culprit before was x86_64 C1, which was fixed to allow Tiered
compilation. Anyhow, with the build fix above, Minimal VM seems to build, bootcycle, and run fine on
x86_64.

> I'm not sure we should be expanding the ability to build the Minimal VM.

I am thinking about the patch as removing the 32-bit special case from the jvm.cfg generation. If we
want to forbid some JVM variants from building on some arches, we should be doing that explicitly
somewhere else.

-Aleksey