RFR: 8230878: ZGC: Use thread_local instead of __thread

[Kim Barrett]

> On Sep 11, 2019, at 6:59 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
> 
>> On Sep 11, 2019, at 4:48 PM, Per Liden <per.liden at oracle.com> wrote:
>> 
>> We're currently using the gcc specific __thread syntax for thread local data. We should make those declarations compiler agnostic.
>> 
>> This patch depends on the proposal to rename THREAD_LOCAL_DECL to thread_local (JDK-8230877), which is currently out for review on hotspot-dev.
>> 
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8230878
>> Webrev: http://cr.openjdk.java.net/~pliden/8230878/webrev.0
>> 
>> /Per
> 
> Looks good.

Retracting that, because of 8230877 discussion.