RFR: Bulk backports sh/jdk11 -> sh/jdk8u

[Aleksey Shipilev]

On 3/15/19 10:48 PM, Roman Kennke wrote:
> This backports outstanding changes from mid-Dec to ~now from shenandoah/jdk11 to shenandoah/jdk8u.
> 
> Find the list of changes here:
> http://cr.openjdk.java.net/~rkennke/backports-sh-jdk8-2019-03-15/changes.txt
> 
> The full webrev:
> http://cr.openjdk.java.net/~rkennke/backports-sh-jdk8-2019-03-15/webrev.00/

*) This comment seem superfluous:

  57   if (os::create_thread(this, os::cgc_thread)) {
  58     // XXX: need to set this to low priority
  59     // unless "agressive mode" set; priority
  60     // should be just less than that of VMThread.
  61     os::set_priority(this, ShenandoahCriticalControlThreadPriority ? CriticalPriority :
NearMaxPriority);
  62     if (!_should_terminate && !DisableStartThread) {
  63       os::start_thread(this);
  64     }
  65   }

*) Indenting is weird here:

  58 template <class E, MEMFLAGS F, unsigned int N>
  59 void BufferedOverflowTaskQueue<E, F, N>::clear() {
  60     _buf_empty = true;
  61     taskqueue_t::set_empty();
  62     taskqueue_t::overflow_stack()->clear();
  63 }

*) Do we have "commonming" typo in other versions?

 391   experimental(bool, ShenandoahCommonGCStateLoads, false,                   \
 392          "Enable commonming for GC state loads in generated code.")         \

*) Asserts seem excessive here, already under UseShenandoahGC branch:

2349 #if INCLUDE_ALL_GCS
2350   if (UseShenandoahGC) {
2351     if (mode == LoopOptsShenandoahExpand) {
2352       assert(UseShenandoahGC, "only for shenandoah");
2353       ShenandoahWriteBarrierNode::pin_and_expand(this);
2354     } else if (mode == LoopOptsShenandoahPostExpand) {
2355       assert(UseShenandoahGC, "only for shenandoah");
2356       visited.Clear();
2357       ShenandoahWriteBarrierNode::optimize_after_expansion(visited, nstack, worklist, this);
2358     }

Otherwise looks good. I haven't reviewed C2 parts carefully.

-Aleksey