RFR(S) 8210864 Reduce the use of metaspaceShared.hpp

[Ioi Lam]

Hi Coleen,

Thanks for the review.

I don’t know how often those asserts are called in debug build. If they happen a lot (per heap object, etc) I don’t want to slow down the debug builds and cause more testing timeouts. So I figured I should rather be safe than sorry.

Thanks
Ioi

> On Sep 18, 2018, at 11:45 AM, coleen.phillimore at oracle.com wrote:
> 
> 
> This seems good but Iis it really necessary for performance to make is_archive_object() inline in metaspaceShared.inline.hpp?
> 
> thanks,
> Coleen
> 
>> On 9/18/18 1:03 PM, Ioi Lam wrote:
>> https://bugs.openjdk.java.net/browse/JDK-8210864
>> http://cr.openjdk.java.net/~iklam/jdk12/8210864-reduce-metaspaceShared-hpp-include.v01/ 
>> 
>> I really hate it whenever I edit metaspaceShared.hpp I have to
>> rebuild almost every source file in HotSpot. That's due to this
>> usage in the popular header file oop.inline.hpp:
>> 
>>     void oopDesc::forward_to(oop p) {
>>       ...
>>       assert(!MetaspaceShared::is_archive_object(oop(this)) &&
>>              !MetaspaceShared::is_archive_object(p),
>>              "forwarding archive object");
>> 
>> 
>> The fix is to change the call to oopDesc::is_archive_object() which is
>> defined out-of-line.
>> 
>> With this change, the number of dependent .o files reduced from 500+ to
>> 45.
>> 
>> I added metaspaceShared.inline.hpp so oopDesc::forward_to should be
>> as fast as before, and all other callers of MetaspaceShared::is_archive_object
>> should be a little faster (probably not measurable).
>> 
>> I also removed a few unnecessary includes of metaspaceShared.hpp
>> 
>> Thanks
>> - Ioi
>