RFR: 8241427: Coarsen locking in Modules::add_module_exports

[Claes Redestad]

Hi again,

updated after offline discussion with Lois:

http://cr.openjdk.java.net/~redestad/8241427/open.01

- replaced package_entry->module() != module_entry checks with
   an assert in get_locked_package_entry.
- removed corresponding throwing of IAEs
- refactored logic in add_module_exports_to_all_unnamed to be
   similar to add_module_exports

Thanks!

/Claes

On 2020-03-23 12:27, Claes Redestad wrote:
> Hi,
> 
> in some places we first lookup a PackageEntry - taking and releasing
> Module_lock - only to then, after some trivial checks - take the
> Module_lock again to update some state in the PackageEntry.
> 
> Coarsening the locking so we only take the mutex once per call brings a
> small improvement to bootstrap (reduction of ~200-250k instructions)
> 
> Webrev: http://cr.openjdk.java.net/~redestad/8241427/open.00/
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8241427
> 
> Testing: tier1-3
> 
> Thanks!
> 
> /Claes