RFR: 8171400: Move checking of duplicate packages in the boot layer to link time

[Alan Bateman]

On 19/12/2016 12:30, Claes Redestad wrote:

> Hi,
>
> this patch adds a check to see if there are any split packages in the 
> system
> modules at link time, and uses this information to enable us to safely 
> skip
> a runtime check during bootstrap for the common case that there are none
> of the sort.
>
> Webrev[1]: http://cr.openjdk.java.net/~redestad/8171400/webrev.01/
> Bug: https://bugs.openjdk.java.net/browse/JDK-8171400
>
> This removes a chunk of the module system bootstrap overhead, and also
> amends a small issue where PACKAGES_IN_BOOT_LAYER would be wrong in the
> presence of split packages.
>
This looks good, just two comments:

1. SystemModules.hasSplitPackages should be clearer if  just said that 
it returns true if the run time images does not contain any split packages.

2. In ModuleBootstrap.boot then you move this code to the if 
needPostResolutionChecks) { ... } block.

-Alan