8252245: Remove ScanClosure

Reviewed-by: pliden, sjohanss

src/hotspot/share/gc/serial/defNewGeneration.cpp

@@ -105,12 +105,6 @@ void DefNewGeneration::FastEvacuateFollowersClosure::do_void() {
   guarantee(_heap->young_gen()->promo_failure_scan_is_complete(), "Failed to finish scan");
 }
 
-ScanClosure::ScanClosure(DefNewGeneration* g, bool gc_barrier) :
-    OopsInClassLoaderDataOrGenClosure(g), _g(g), _gc_barrier(gc_barrier)
-{
-  _boundary = _g->reserved().end();
-}
-
 FastScanClosure::FastScanClosure(DefNewGeneration* g, bool gc_barrier) :
     OopsInClassLoaderDataOrGenClosure(g), _g(g), _gc_barrier(gc_barrier)
 {

src/hotspot/share/gc/serial/defNewGeneration.hpp

@@ -35,7 +35,6 @@
 #include "utilities/stack.hpp"
 
 class ContiguousSpace;
-class ScanClosure;
 class STWGCTimer;
 class CSpaceCounters;
 class ScanWeakRefClosure;

src/hotspot/share/gc/shared/genOopClosures.hpp

@@ -102,27 +102,10 @@ class OopsInClassLoaderDataOrGenClosure: public BasicOopsInGenClosure {
 
 #if INCLUDE_SERIALGC
 
-// Closure for scanning DefNewGeneration.
-//
-// This closure will perform barrier store calls for ALL
-// pointers in scanned oops.
-class ScanClosure: public OopsInClassLoaderDataOrGenClosure {
- private:
-  DefNewGeneration* _g;
-  HeapWord*         _boundary;
-  bool              _gc_barrier;
-  template <class T> inline void do_oop_work(T* p);
- public:
-  ScanClosure(DefNewGeneration* g, bool gc_barrier);
-  virtual void do_oop(oop* p);
-  virtual void do_oop(narrowOop* p);
-};
-
 // Closure for scanning DefNewGeneration.
 //
 // This closure only performs barrier store calls on
-// pointers into the DefNewGeneration. This is less
+// pointers into the DefNewGeneration.
-// precise, but faster, than a ScanClosure
 class FastScanClosure: public OopsInClassLoaderDataOrGenClosure {
  protected:
   DefNewGeneration* _g;
@@ -168,9 +151,8 @@ class FilteringClosure: public OopIterateClosure {
 #if INCLUDE_SERIALGC
 
 // Closure for scanning DefNewGeneration's weak references.
-// NOTE: very much like ScanClosure but not derived from
+//  -- weak references are processed all at once,
-//  OopsInGenClosure -- weak references are processed all
+//  with no notion of which generation they were in.
-//  at once, with no notion of which generation they were in.
 class ScanWeakRefClosure: public OopClosure {
  protected:
   DefNewGeneration* _g;

src/hotspot/share/gc/shared/genOopClosures.inline.hpp

@@ -74,34 +74,6 @@ inline void OopsInClassLoaderDataOrGenClosure::do_cld_barrier() {
 
 #if INCLUDE_SERIALGC
 
-// NOTE! Any changes made here should also be made
-// in FastScanClosure::do_oop_work()
-template <class T> inline void ScanClosure::do_oop_work(T* p) {
-  T heap_oop = RawAccess<>::oop_load(p);
-  // Should we copy the obj?
-  if (!CompressedOops::is_null(heap_oop)) {
-    oop obj = CompressedOops::decode_not_null(heap_oop);
-    if (cast_from_oop<HeapWord*>(obj) < _boundary) {
-      assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");
-      oop new_obj = obj->is_forwarded() ? obj->forwardee()
-                                        : _g->copy_to_survivor_space(obj);
-      RawAccess<IS_NOT_NULL>::oop_store(p, new_obj);
-    }
-
-    if (is_scanning_a_cld()) {
-      do_cld_barrier();
-    } else if (_gc_barrier) {
-      // Now call parent closure
-      do_barrier(p);
-    }
-  }
-}
-
-inline void ScanClosure::do_oop(oop* p)       { ScanClosure::do_oop_work(p); }
-inline void ScanClosure::do_oop(narrowOop* p) { ScanClosure::do_oop_work(p); }
-
-// NOTE! Any changes made here should also be made
-// in ScanClosure::do_oop_work()
 template <class T> inline void FastScanClosure::do_oop_work(T* p) {
   T heap_oop = RawAccess<>::oop_load(p);
   // Should we copy the obj?
@@ -142,7 +114,7 @@ inline void FilteringClosure::do_oop(narrowOop* p) { FilteringClosure::do_oop_wo
 
 #if INCLUDE_SERIALGC
 
-// Note similarity to ScanClosure; the difference is that
+// Note similarity to FastScanClosure; the difference is that
 // the barrier set is taken care of outside this closure.
 template <class T> inline void ScanWeakRefClosure::do_oop_work(T* p) {
   oop obj = RawAccess<IS_NOT_NULL>::oop_load(p);

src/hotspot/share/gc/shared/generation.hpp

@@ -57,7 +57,6 @@ class ContiguousSpace;
 class CompactPoint;
 class OopsInGenClosure;
 class OopClosure;
-class ScanClosure;
 class FastScanClosure;
 class GenCollectedHeap;
 class GCStats;

src/hotspot/share/oops/oop.hpp

@@ -42,7 +42,6 @@
 
 // Forward declarations.
 class OopClosure;
-class ScanClosure;
 class FastScanClosure;
 class FilteringClosure;