1 /*
   2  * Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 // Inline functions of BarrierSet, which de-virtualize certain
  26 // performance-critical calls when the barrier is the most common
  27 // card-table kind.
  28 
  29 template <class T> void BarrierSet::write_ref_field_pre(T* field, oop new_val) {
  30   if (kind() == CardTableModRef) {
  31     ((CardTableModRefBS*)this)->inline_write_ref_field_pre(field, new_val);
  32   } else {
  33     write_ref_field_pre_work(field, new_val);
  34   }
  35 }
  36 
  37 void BarrierSet::write_ref_field(void* field, oop new_val) {
  38   if (kind() == CardTableModRef) {
  39     ((CardTableModRefBS*)this)->inline_write_ref_field(field, new_val);
  40   } else {
  41     write_ref_field_work(field, new_val);
  42   }
  43 }
  44 
  45 // count is number of array elements being written
  46 void BarrierSet::write_ref_array(HeapWord* start, size_t count) {
  47   assert(count <= (size_t)max_intx, "count too large");
  48   HeapWord* end = (HeapWord*)((char*)start + (count*heapOopSize));
  49   // In the case of compressed oops, start and end may potentially be misaligned;
  50   // so we need to conservatively align the first downward (this is not
  51   // strictly necessary for current uses, but a case of good hygiene and,
  52   // if you will, aesthetics) and the second upward (this is essential for
  53   // current uses) to a HeapWord boundary, so we mark all cards overlapping
  54   // this write. If this evolves in the future to calling a
  55   // logging barrier of narrow oop granularity, like the pre-barrier for G1
  56   // (mentioned here merely by way of example), we will need to change this
  57   // interface, so it is "exactly precise" (if i may be allowed the adverbial
  58   // redundancy for emphasis) and does not include narrow oop slots not
  59   // included in the original write interval.
  60   HeapWord* aligned_start = (HeapWord*)align_size_down((uintptr_t)start, HeapWordSize);
  61   HeapWord* aligned_end   = (HeapWord*)align_size_up  ((uintptr_t)end,   HeapWordSize);
  62   // If compressed oops were not being used, these should already be aligned
  63   assert(UseCompressedOops || (aligned_start == start && aligned_end == end),
  64          "Expected heap word alignment of start and end");
  65 #if 0
  66   warning("Post:\t" INTPTR_FORMAT "[" SIZE_FORMAT "] : [" INTPTR_FORMAT","INTPTR_FORMAT")\t",
  67                    start,            count,              aligned_start,   aligned_end);
  68 #endif
  69   write_ref_array_work(MemRegion(aligned_start, aligned_end));
  70 }
  71 
  72 
  73 void BarrierSet::write_region(MemRegion mr) {
  74   if (kind() == CardTableModRef) {
  75     ((CardTableModRefBS*)this)->inline_write_region(mr);
  76   } else {
  77     write_region_work(mr);
  78   }
  79 }