[Bug 2297] [IcedTea7] Use the IcedTea 2.6.0 HotSpot for ARM32 by default

[Andrew Hughes]

----- Original Message -----
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> On 15/04/15 10:05, Andrew Haley wrote:
> >> (IT_WITH_HOTSPOT_BUILD): Use 'aarch64' when JRE_ARCH_DIR is
> >> either arm or aarch64.
> > 
> > Really?  Why is that?
> 
> I was also asking myself the same and this is the answer that comes
> from reading the code and inspecting the branches. In 2.6.0, there is
> only one tarball for hotspot: all the aarch64 changes are integrated
> in the icedtea7-forest/hotspot. Since Ed's arm32 micro-jit is
> integrated there too and since the arm32 build correctly with that
> tarball and the micro-jit, IMHO, instead of backporting patches to the
> hotspot tarball that is used for other architectures, Andrew simply
> decided to use the one that has the relevant patches already integrated.
> 
> That is my reading of
> http://icedtea.classpath.org/hg/release/icedtea7-2.5/rev/38192e372210
> 
> Cheers
> 
> Fridrich
> 
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Yes, as stated in the description of the bug:

"AArch64 currently uses the 2.6.0 pre-release HotSpot tarball by default
on 2.5.x so that the AArch64 JIT is available to it. We should default
ARM32 to the same HotSpot tarball, so as to bring in PR2228, ahead of
the 2.6.0 release."

http://icedtea.classpath.org/bugzilla/show_bug.cgi?id=2297

The advantage this has over backporting the patches is it's optional;
if the 2.5.5 HotSpot (used by amd64, etc.) is required for arm32 platforms
instead, it can be used simply by specifying --with-hotspot-build=default.

This is documented in INSTALL under "Support for Different Versions of HotSpot";

'Currently, IcedTea 2.x supports the 'default' HotSpot tree, which is
part of the IcedTea forest for the particular minor release series
being used, and 'aarch64', which uses snapshots of the HotSpot tree
from the forthcoming 2.6.0 release of IcedTea. The latter is the default
on both the ARM 32 and AArch64 architectures.'
-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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