8047820: G1 Block offset table does not need to support generic Space classes

Reviewed-by: tschatzl, stefank

hotspot/src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp

@@ -24,6 +24,7 @@
 
 #include "precompiled.hpp"
 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
+#include "gc_implementation/g1/heapRegion.hpp"
 #include "memory/space.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/java.hpp"
@@ -98,6 +99,20 @@ bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const {
   return (delta & right_n_bits(LogN_words)) == (size_t)NoBits;
 }
 
+void G1BlockOffsetSharedArray::set_offset_array(HeapWord* left, HeapWord* right, u_char offset) {
+  check_index(index_for(right - 1), "right address out of range");
+  assert(left  < right, "Heap addresses out of order");
+  size_t num_cards = pointer_delta(right, left) >> LogN_words;
+  if (UseMemSetInBOT) {
+    memset(&_offset_array[index_for(left)], offset, num_cards);
+  } else {
+    size_t i = index_for(left);
+    const size_t end = i + num_cards;
+    for (; i < end; i++) {
+      _offset_array[i] = offset;
+    }
+  }
+}
 
 //////////////////////////////////////////////////////////////////////
 // G1BlockOffsetArray
@@ -107,7 +122,7 @@ G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array,
                                        MemRegion mr, bool init_to_zero) :
   G1BlockOffsetTable(mr.start(), mr.end()),
   _unallocated_block(_bottom),
-  _array(array), _csp(NULL),
+  _array(array), _gsp(NULL),
   _init_to_zero(init_to_zero) {
   assert(_bottom <= _end, "arguments out of order");
   if (!_init_to_zero) {
@@ -117,9 +132,8 @@ G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array,
   }
 }
 
-void G1BlockOffsetArray::set_space(Space* sp) {
-  _sp = sp;
-  _csp = sp->toContiguousSpace();
+void G1BlockOffsetArray::set_space(G1OffsetTableContigSpace* sp) {
+  _gsp = sp;
 }
 
 // The arguments follow the normal convention of denoting
@@ -378,7 +392,7 @@ G1BlockOffsetArray::block_start_unsafe_const(const void* addr) const {
   }
   // Otherwise, find the block start using the table.
   HeapWord* q = block_at_or_preceding(addr, false, 0);
-  HeapWord* n = q + _sp->block_size(q);
+  HeapWord* n = q + block_size(q);
   return forward_to_block_containing_addr_const(q, n, addr);
 }
 
@@ -406,8 +420,7 @@ G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q,
          err_msg("next_boundary is beyond the end of the covered region "
                  " next_boundary " PTR_FORMAT " _array->_end " PTR_FORMAT,
                  next_boundary, _array->_end));
-  if (csp() != NULL) {
-    if (addr >= csp()->top()) return csp()->top();
+  if (addr >= gsp()->top()) return gsp()->top();
   while (next_boundary < addr) {
     while (n <= next_boundary) {
       q = n;
@@ -419,19 +432,6 @@ G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q,
     // [q, n) is the block that crosses the boundary.
     alloc_block_work2(&next_boundary, &next_index, q, n);
   }
-  } else {
-    while (next_boundary < addr) {
-      while (n <= next_boundary) {
-        q = n;
-        oop obj = oop(q);
-        if (obj->klass_or_null() == NULL) return q;
-        n += _sp->block_size(q);
-      }
-      assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
-      // [q, n) is the block that crosses the boundary.
-      alloc_block_work2(&next_boundary, &next_index, q, n);
-    }
-  }
   return forward_to_block_containing_addr_const(q, n, addr);
 }
 
@@ -637,7 +637,7 @@ block_start_unsafe_const(const void* addr) const {
   assert(_bottom <= addr && addr < _end,
          "addr must be covered by this Array");
   HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
-  HeapWord* n = q + _sp->block_size(q);
+  HeapWord* n = q + block_size(q);
   return forward_to_block_containing_addr_const(q, n, addr);
 }
 

hotspot/src/share/vm/gc_implementation/g1/g1BlockOffsetTable.hpp

@@ -52,8 +52,8 @@
 // consolidation.
 
 // Forward declarations
-class ContiguousSpace;
 class G1BlockOffsetSharedArray;
+class G1OffsetTableContigSpace;
 
 class G1BlockOffsetTable VALUE_OBJ_CLASS_SPEC {
   friend class VMStructs;
@@ -157,6 +157,8 @@ private:
     return _offset_array[index];
   }
 
+  void set_offset_array(HeapWord* left, HeapWord* right, u_char offset);
+
   void set_offset_array(size_t index, u_char offset) {
     check_index(index, "index out of range");
     check_offset(offset, "offset too large");
@@ -170,21 +172,6 @@ private:
     _offset_array[index] = (u_char) pointer_delta(high, low);
   }
 
-  void set_offset_array(HeapWord* left, HeapWord* right, u_char offset) {
-    check_index(index_for(right - 1), "right address out of range");
-    assert(left  < right, "Heap addresses out of order");
-    size_t num_cards = pointer_delta(right, left) >> LogN_words;
-    if (UseMemSetInBOT) {
-      memset(&_offset_array[index_for(left)], offset, num_cards);
-    } else {
-      size_t i = index_for(left);
-      const size_t end = i + num_cards;
-      for (; i < end; i++) {
-        _offset_array[i] = offset;
-      }
-    }
-  }
-
   void set_offset_array(size_t left, size_t right, u_char offset) {
     check_index(right, "right index out of range");
     assert(left <= right, "indexes out of order");
@@ -281,11 +268,7 @@ private:
   G1BlockOffsetSharedArray* _array;
 
   // The space that owns this subregion.
-  Space* _sp;
-
-  // If "_sp" is a contiguous space, the field below is the view of "_sp"
-  // as a contiguous space, else NULL.
-  ContiguousSpace* _csp;
+  G1OffsetTableContigSpace* _gsp;
 
   // If true, array entries are initialized to 0; otherwise, they are
   // initialized to point backwards to the beginning of the covered region.
@@ -310,7 +293,9 @@ private:
 
 protected:
 
-  ContiguousSpace* csp() const { return _csp; }
+  G1OffsetTableContigSpace* gsp() const { return _gsp; }
+
+  inline size_t block_size(const HeapWord* p) const;
 
   // Returns the address of a block whose start is at most "addr".
   // If "has_max_index" is true, "assumes "max_index" is the last valid one
@@ -363,7 +348,7 @@ public:
   // "this" to be passed as a parameter to a member constructor for
   // the containing concrete subtype of Space.
   // This would be legal C++, but MS VC++ doesn't allow it.
-  void set_space(Space* sp);
+  void set_space(G1OffsetTableContigSpace* sp);
 
   // Resets the covered region to the given "mr".
   void set_region(MemRegion mr);

hotspot/src/share/vm/gc_implementation/g1/g1BlockOffsetTable.inline.hpp

@@ -26,6 +26,7 @@
 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
 
 #include "gc_implementation/g1/g1BlockOffsetTable.hpp"
+#include "gc_implementation/g1/heapRegion.hpp"
 #include "memory/space.hpp"
 
 inline HeapWord* G1BlockOffsetTable::block_start(const void* addr) {
@@ -69,6 +70,11 @@ G1BlockOffsetSharedArray::address_for_index(size_t index) const {
   return result;
 }
 
+inline size_t
+G1BlockOffsetArray::block_size(const HeapWord* p) const {
+  return gsp()->block_size(p);
+}
+
 inline HeapWord*
 G1BlockOffsetArray::block_at_or_preceding(const void* addr,
                                           bool has_max_index,
@@ -88,7 +94,7 @@ G1BlockOffsetArray::block_at_or_preceding(const void* addr,
     // to go back by.
     size_t n_cards_back = BlockOffsetArray::entry_to_cards_back(offset);
     q -= (N_words * n_cards_back);
-    assert(q >= _sp->bottom(), "Went below bottom!");
+    assert(q >= gsp()->bottom(), "Went below bottom!");
     index -= n_cards_back;
     offset = _array->offset_array(index);
   }
@@ -101,22 +107,13 @@ inline HeapWord*
 G1BlockOffsetArray::
 forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n,
                                        const void* addr) const {
-  if (csp() != NULL) {
-    if (addr >= csp()->top()) return csp()->top();
+  if (addr >= gsp()->top()) return gsp()->top();
   while (n <= addr) {
     q = n;
     oop obj = oop(q);
     if (obj->klass_or_null() == NULL) return q;
     n += obj->size();
   }
-  } else {
-    while (n <= addr) {
-      q = n;
-      oop obj = oop(q);
-      if (obj->klass_or_null() == NULL) return q;
-      n += _sp->block_size(q);
-    }
-  }
   assert(q <= n, "wrong order for q and addr");
   assert(addr < n, "wrong order for addr and n");
   return q;
@@ -126,7 +123,7 @@ inline HeapWord*
 G1BlockOffsetArray::forward_to_block_containing_addr(HeapWord* q,
                                                      const void* addr) {
   if (oop(q)->klass_or_null() == NULL) return q;
-  HeapWord* n = q + _sp->block_size(q);
+  HeapWord* n = q + block_size(q);
   // In the normal case, where the query "addr" is a card boundary, and the
   // offset table chunks are the same size as cards, the block starting at
   // "q" will contain addr, so the test below will fail, and we'll fall

hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp

@@ -25,7 +25,7 @@
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
 
-#include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
+#include "gc_implementation/g1/g1BlockOffsetTable.hpp"
 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp"
 #include "gc_implementation/g1/survRateGroup.hpp"
 #include "gc_implementation/shared/ageTable.hpp"

hotspot/src/share/vm/gc_implementation/g1/heapRegion.inline.hpp

@@ -25,6 +25,8 @@
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP
 
+#include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
+
 inline HeapWord* G1OffsetTableContigSpace::allocate(size_t size) {
   HeapWord* res = ContiguousSpace::allocate(size);
   if (res != NULL) {