RFR: 8226822: GC interface for C1 runtime calls

[Roman Kennke]

Thanks, Nils!

Roman

> Looks good,
> 
> // Nils
> 
> On 2019-07-01 16:51, Roman Kennke wrote:
>>   Currently, it is not possible for GC to emit runtime calls in C1
>> without touching shared code, because it needs to be known in
>> c1_Runtime.hpp/cpp.
>>
>> This patch adds a little hook to allow the GC to make runtime calls
>> known.
>>
>> This is a prerequisite for:
>> https://bugs.openjdk.java.net/browse/JDK-8226695
>>
>>
>> Bug:
>> https://bugs.openjdk.java.net/browse/JDK-8226822
>> Webrev:
>> http://cr.openjdk.java.net/~rkennke/JDK-8226822/webrev/
>>
>> Can I please get reviews?
>>
>> Thanks, Roman
>>