src/hotspot/share/gc/g1/g1RootClosures.cpp

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#include "gc/g1/g1OopClosures.inline.hpp"
#include "gc/g1/g1RootClosures.hpp"
#include "gc/g1/g1SharedClosures.hpp"

// Closures used for standard G1 evacuation.
class G1EvacuationClosures : public G1EvacuationRootClosures {
  G1SharedClosures<false> _closures;

public:
  G1EvacuationClosures(G1CollectedHeap* g1h,
                       G1ParScanThreadState* pss,
                       bool in_young_gc) :
      _closures(g1h, pss, in_young_gc) {}

  OopClosure* strong_oops() { return &_closures._oops; }

  CLDClosure* weak_clds()             { return &_closures._clds; }
  CLDClosure* strong_clds()           { return &_closures._clds; }

  NMethodClosure* strong_nmethods()   { return &_closures._nmethods; }
  NMethodClosure* weak_nmethods()     { return &_closures._nmethods; }
};

// Closures used during concurrent start.
// The treatment of "weak" roots is selectable through the template parameter,
// this is usually used to control unloading of classes and interned strings.
template <bool should_mark_weak>
class G1ConcurrentStartMarkClosures : public G1EvacuationRootClosures {
  G1SharedClosures<true>             _strong;
  G1SharedClosures<should_mark_weak> _weak;

public:
  G1ConcurrentStartMarkClosures(G1CollectedHeap* g1h,
                                G1ParScanThreadState* pss) :
      _strong(g1h, pss, /* process_only_dirty_klasses */ false),
      _weak(g1h, pss,   /* process_only_dirty_klasses */ false) {}

  OopClosure* strong_oops() { return &_strong._oops; }

  CLDClosure* weak_clds()             { return &_weak._clds; }
  CLDClosure* strong_clds()           { return &_strong._clds; }

  NMethodClosure* strong_nmethods()   { return &_strong._nmethods; }
  NMethodClosure* weak_nmethods()     { return &_weak._nmethods; }
};

G1EvacuationRootClosures* G1EvacuationRootClosures::create_root_closures(G1CollectedHeap* g1h,
                                                                         G1ParScanThreadState* pss,
                                                                         bool process_only_dirty_klasses) {
  G1EvacuationRootClosures* res = nullptr;
  if (g1h->collector_state()->in_concurrent_start_gc()) {
    if (ClassUnloadingWithConcurrentMark) {
      res = new G1ConcurrentStartMarkClosures<false>(g1h, pss);
    } else {
      res = new G1ConcurrentStartMarkClosures<true>(g1h, pss);
    }
  } else {
    res = new G1EvacuationClosures(g1h, pss, process_only_dirty_klasses);
  }
  return res;
}