Hotspot makefile conversion now in build-infra

[David Holmes]

Hi Magnus,

Slowly catching up after vacation ...

I'm surprised this hasn't gone out to hotspot-dev as I would think 
hotspot developers would be most interested in this and provide 
feedback. But perhaps you are not quite ready for that?

Will this still allow a hotspot repo to be built in isolation or will it 
now require that a full forest always be present? (well at least 
top-level repo plus hotspot repo).

There are a number of open RFE's for hotspot build to deal with issues 
related to integration with configure or that should be readily/easily 
solvable by a rewrite that utilizes approaches from the new build:

https://bugs.openjdk.java.net/browse/JDK-8016041
https://bugs.openjdk.java.net/browse/JDK-8016039
https://bugs.openjdk.java.net/browse/JDK-7195896

I'd be more than happy to see these all resolved by the current rewrite :)

I will try to take a look at this but like many am about to depart 
(again!) for Xmas vacation. :)

Cheers,
David

On 5/12/2013 8:49 PM, Magnus Ihse Bursie wrote:
> We have just "re-opened" the build-infra project (repos and mailing
> list) for the continuation of the conversion of the old build system.
>
> "Hey, wasn't that finished already?" you might be thinking.
> Unfortunately, no. Due to constraints, we left out a major component in
> the conversion -- hotspot.
>
> I and Erik have been working on a prototype for building Hotspot using
> the new build system. It has been developed in a private repository, but
> is now ready to be moved to build-infra.
>
> You are of course welcome to try it out, but unless you're eager, it is
> probably a bit too early. :-) The current prototype has the following
> limitations/properties:
> * It has only been tested (and probably only work) on linux-x86_64.
> * It creates roughly the correct collection of files in the
> build/hotspot/dist directory.
> * It compiles roughly the correct set of native files, with roughly the
> correct set of compiler flags.
> * It creates jar files with roughly the correct contents.
>
> However, the compare script clearly shows that "roughly" does still not
> mean "identical". :-)
>
> Going forward, we need to add support for all platforms, and make sure
> that the built bits indeed end up identical to the old build system.
> There are also several pieces of functionality in the current build
> system that needs to be addressed.
>
> On the bright side, we can already (with no optimizations being done
> whatsoever) see a slight speed increase (2 min 11 sec vs 2 min 35 sec on
> my machine). But most of all, we see a clear reduction of complexity of
> the build system. Compare:
>
> magnusi at ../hotspot/make$ wc `find . -type f` | grep total
>   22527  94124 803058 total
>
> with
>
> magnusi at .../hotspot/makefiles$ wc `find . -type f` | grep total
>    753  3686 32369 total
>
> While this will surely double in size before we're done, it's still an
> order of magnitude simpler.
>
> /Magnus