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 # include "incls/_precompiled.incl"
  26 # include "incls/_freeChunk.cpp.incl"
  27 
  28 #ifndef PRODUCT
  29 
  30 #define baadbabeHeapWord badHeapWordVal
  31 #define deadbeefHeapWord 0xdeadbeef
  32 
  33 size_t const FreeChunk::header_size() {
  34   return sizeof(FreeChunk)/HeapWordSize;
  35 }
  36 
  37 void FreeChunk::mangleAllocated(size_t size) {
  38   // mangle all but the header of a just-allocated block
  39   // of storage
  40   assert(size >= MinChunkSize, "smallest size of object");
  41   // we can't assert that _size == size because this may be an
  42   // allocation out of a linear allocation block
  43   assert(sizeof(FreeChunk) % HeapWordSize == 0,
  44          "shouldn't write beyond chunk");
  45   HeapWord* addr = (HeapWord*)this;
  46   size_t hdr = header_size();
  47   Copy::fill_to_words(addr + hdr, size - hdr, baadbabeHeapWord);
  48 }
  49 
  50 void FreeChunk::mangleFreed(size_t sz) {
  51   assert(baadbabeHeapWord != deadbeefHeapWord, "Need distinct patterns");
  52   // mangle all but the header of a just-freed block of storage
  53   // just prior to passing it to the storage dictionary
  54   assert(sz >= MinChunkSize, "smallest size of object");
  55   assert(sz == size(), "just checking");
  56   HeapWord* addr = (HeapWord*)this;
  57   size_t hdr = header_size();
  58   Copy::fill_to_words(addr + hdr, sz - hdr, deadbeefHeapWord);
  59 }
  60 
  61 void FreeChunk::verifyList() const {
  62   FreeChunk* nextFC = next();
  63   if (nextFC != NULL) {
  64     assert(this == nextFC->prev(), "broken chain");
  65     assert(size() == nextFC->size(), "wrong size");
  66     nextFC->verifyList();
  67   }
  68 }
  69 #endif
  70 
  71 void FreeChunk::print_on(outputStream* st) {
  72   st->print_cr("Next: " PTR_FORMAT " Prev: " PTR_FORMAT " %s",
  73     next(), prev(), cantCoalesce() ? "[can't coalesce]" : "");
  74 }