8323726: Serial: Remove unused definitions in Generation

Reviewed-by: stefank

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

@@ -1104,11 +1104,6 @@ const char* DefNewGeneration::name() const {
   return "def new generation";
 }
 
-// Moved from inline file as they are not called inline
-ContiguousSpace* DefNewGeneration::first_compaction_space() const {
-  return eden();
-}
-
 HeapWord* DefNewGeneration::allocate(size_t word_size, bool is_tlab) {
   // This is the slow-path allocation for the DefNewGeneration.
   // Most allocations are fast-path in compiled code.

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

@@ -168,8 +168,6 @@ class DefNewGeneration: public Generation {
   ContiguousSpace* from() const           { return _from_space; }
   ContiguousSpace* to()   const           { return _to_space;   }
 
-  virtual ContiguousSpace* first_compaction_space() const;
-
   // Space enquiries
   size_t capacity() const;
   size_t used() const;

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

@@ -55,16 +55,6 @@ class ContiguousSpace;
 class OopClosure;
 class GCStats;
 
-// A "ScratchBlock" represents a block of memory in one generation usable by
-// another.  It represents "num_words" free words, starting at and including
-// the address of "this".
-struct ScratchBlock {
-  ScratchBlock* next;
-  size_t num_words;
-  HeapWord scratch_space[1];  // Actually, of size "num_words-2" (assuming
-                              // first two fields are word-sized.)
-};
-
 class Generation: public CHeapObj<mtGC> {
   friend class VMStructs;
  private:
@@ -175,10 +165,6 @@ class Generation: public CHeapObj<mtGC> {
   // Iteration - do not use for time critical operations
   virtual void space_iterate(SpaceClosure* blk, bool usedOnly = false) = 0;
 
-  // Returns the first space, if any, in the generation that can participate
-  // in compaction, or else "null".
-  virtual ContiguousSpace* first_compaction_space() const = 0;
-
   // Returns "true" iff this generation should be used to allocate an
   // object of the given size.  Young generations might
   // wish to exclude very large objects, for example, since, if allocated

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

@@ -101,8 +101,6 @@ class TenuredGeneration: public Generation {
 
   bool is_in(const void* p) const;
 
-  ContiguousSpace* first_compaction_space() const;
-
   TenuredGeneration(ReservedSpace rs,
                     size_t initial_byte_size,
                     size_t min_byte_size,

src/hotspot/share/gc/serial/tenuredGeneration.inline.hpp

@@ -49,10 +49,6 @@ inline bool TenuredGeneration::is_in(const void* p) const {
   return space()->is_in(p);
 }
 
-inline ContiguousSpace* TenuredGeneration::first_compaction_space() const {
-  return space();
-}
-
 HeapWord* TenuredGeneration::allocate(size_t word_size,
                                                  bool is_tlab) {
   assert(!is_tlab, "TenuredGeneration does not support TLAB allocation");