HotSpot just got Hotter - IcedTea6 support for latest HotSpot

[Mark Wielaard]

Hi Andrew,

I CCed hotspot-dev to see if the hotspot hackers can also provide some
feedback (on picking the right hotspot version to ship by default).

On Mon, 2008-12-01 at 17:37 +0000, Andrew John Hughes wrote:
> I've added two new options to IcedTea6:
> 
> --with-hotspot-build=x
> --with-hotspot-src-zip=<path>
> 
> When --with-hotspot-build is given, the build will attempt to use the
> specified version of HotSpot.  The version numbers are contained in
> the new file hotspot.map which maps build numbers to changesets. The
> build number is also used in the name of some patches so correct
> versions are applied.  This may yet be simplified to just do old/new.
> Feedback welcome.
> 
> With this patch, the build defaults to using hs14.0b08 (the current
> OJ7 HotSpot) and will download this from hg.openjdk.java.net unless
> --with-hotspot-src-zip is used.  --with-hotspot-build=original or
> --without-hotspot-build will disable this and return to the existing
> hs10.0b19 version.

Wow, this is pretty cool! It should make it much simpler to try out and
use a newer hotspot with the stable, openjdk6 based, core.

I think that supporting more than 2, lets call them "stable" and
"latest", might be a bit ambitious. We risk having to try to keep up
with all the different versions and duplicating all our patches against
more and more versions. This is also why I CCed hotspot-dev, hopefully
they can advise on the best values for "stable" (what is used in update
10 for example?) and "latest" (should be ok, but we wouldn't advise it
for production yet).

Ideally, we make sure that the "stable" version is the version
backported also to openjdk6 itself. Or maybe 3 versions at most
"openjdk6 base", "stable/production", "latest"?

Encoding the versions in the patch file names is slightly ugly imho. If
at all possible try moving them into their own subdirectory. (This is
more in general, not particular for your patch, the patches dir is
growing at an alarming rate, I guess I should have done the subdir thing
myself also for the new xrender patch set.)

Also it would be great to have hotspot patches that are just for any
version. For example I saw the sparc-ptracefix that is identical for
both versions (just a random pick, I didn't actually go over all
patches).

Note that the openjdk6 hotspot actually contains some tests that aren't
in the newer hotspot repo. It would be nice if we never got less tests
(currently there are 20, including one icedtea only one - the lucene
test).

Thanks for doing this. It will be nice to easily plug in newer hotspots.

Cheers,

Mark