RFR: JDK-8241463 Move build tools to respective modules

[Alan Bateman]

On 23/03/2020 19:03, Magnus Ihse Bursie wrote:
> The build tools (small java tools that are run during the build to 
> generate source code, or data, needed in the JDK) have historically 
> been placed in the "make" directory. This maybe made sense long time 
> ago, but does not do so anymore.
>
> Instead, the build tools source code should move the the module that 
> needs them. For instance, compilefontconfig should move to 
> java.desktop, etc.
>
> There are multiple reasons for this:
>
> * Currently we build *all* build tools at once, which mean that we 
> cannot compile java.base until e.g. the compilefontconfig tool is 
> compiled, even though it is not needed.
>
> * If a build tool, e.g. compilefontconfig is modified, all build tools 
> are recompiled, which triggers a rebuild of more or less the entire 
> JDK. This makes development of the build tools unnecessary tedious.
>
> * When the build tools are modified, the group owning the 
> corresponding module is the proper review instance, not the build 
> team. But since they reside under "make", the review mails often 
> include build-dev, but this is mostly noise for us. With this move, 
> the ownership is made clear.
>
> In this patch, I have not modified how and when the build tools are 
> compiled, but this shuffle is the prerequisite for continuing with 
> that in a follow-up patch.
>
> I have also moved the build tools to the org.openjdk.buildtools.* 
> package name space (inspired by Skara), instead of the strangely named 
> build.tools.* name space.
>
> A few build tools are not moved in this patch. Two of them, 
> charsetmapping and cldrconverter, are shared between two modules. (I 
> think they should move to modules nevertheless, but they need some 
> more thought to make sure I do this right.) The rest are tools that 
> are needed for the build in general, like linking or javadoc support. 
> I'll move this to a better location too, but in a separate patch.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8241463
> WebRev: 
> http://cr.openjdk.java.net/~ihse/JDK-8241463-move-build-tools-to-modules/webrev.01
I think this will require further discussion, maybe even an update to 
JEP 201. I think it would be useful to see what other options were 
exploring, in particular options that organize the tools by module in 
the make tree (as it will confuse people to put them in the src tree).

-Alan