--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/memory/archiveUtils.hpp	Wed Nov 13 16:36:54 2019 -0800
@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_MEMORY_ARCHIVEUTILS_HPP
+#define SHARE_MEMORY_ARCHIVEUTILS_HPP
+
+#include "logging/log.hpp"
+#include "runtime/arguments.hpp"
+#include "utilities/bitMap.hpp"
+
+// ArchivePtrMarker is used to mark the location of pointers embedded in a CDS archive. E.g., when an
+// InstanceKlass k is dumped, we mark the location of the k->_name pointer by effectively calling
+// mark_pointer(/*ptr_loc=*/&k->_name). It's required that (_prt_base <= ptr_loc < _ptr_end). _ptr_base is
+// fixed, but _ptr_end can be expanded as more objects are dumped.
+class ArchivePtrMarker : AllStatic {
+  static CHeapBitMap* _ptrmap;
+  static address*     _ptr_base;
+  static address*     _ptr_end;
+
+  // Once _ptrmap is compacted, we don't allow bit marking anymore. This is to
+  // avoid unintentional copy operations after the bitmap has been finalized and written.
+  static bool         _compacted;
+public:
+  static void initialize(CHeapBitMap* ptrmap, address* ptr_base, address* ptr_end);
+  static void mark_pointer(address* ptr_loc);
+  static void compact(address relocatable_base, address relocatable_end);
+  static void compact(size_t max_non_null_offset);
+
+  template <typename T>
+  static void mark_pointer(T* ptr_loc) {
+    mark_pointer((address*)ptr_loc);
+  }
+
+  static void expand_ptr_end(address *new_ptr_end) {
+    assert(_ptr_end <= new_ptr_end, "must be");
+    _ptr_end = new_ptr_end;
+  }
+
+  static CHeapBitMap* ptrmap() {
+    return _ptrmap;
+  }
+};
+
+// SharedDataRelocator is used to shift pointers in the CDS archive.
+//
+// The CDS archive is basically a contiguous block of memory (divided into several regions)
+// that contains multiple objects. The objects may contain direct pointers that point to other objects
+// within the archive (e.g., InstanceKlass::_name points to a Symbol in the archive). During dumping, we
+// built a bitmap that marks the locations of all these pointers (using ArchivePtrMarker, see comments above).
+//
+// The contents of the archive assumes that it’s mapped at the default SharedBaseAddress (e.g. 0x800000000).
+// If the archive ends up being mapped at a different address (e.g. 0x810000000), SharedDataRelocator
+// is used to shift each marked pointer by a delta (0x10000000 in this example), so that it points to
+// the actually mapped location of the target object.
+template <bool COMPACTING>
+class SharedDataRelocator: public BitMapClosure {
+  // for all (address** p), where (is_marked(p) && _patch_base <= p && p < _patch_end) { *p += delta; }
+
+  // Patch all pointers within this region that are marked.
+  address* _patch_base;
+  address* _patch_end;
+
+  // Before patching, all pointers must point to this region.
+  address _valid_old_base;
+  address _valid_old_end;
+
+  // After patching, all pointers must point to this region.
+  address _valid_new_base;
+  address _valid_new_end;
+
+  // How much to relocate for each pointer.
+  intx _delta;
+
+  // The following fields are used only when COMPACTING == true;
+  // The highest offset (inclusive) in the bitmap that contains a non-null pointer.
+  // This is used at dump time to reduce the size of the bitmap (which may have been over-allocated).
+  size_t _max_non_null_offset;
+  CHeapBitMap* _ptrmap;
+
+ public:
+  SharedDataRelocator(address* patch_base, address* patch_end,
+                      address valid_old_base, address valid_old_end,
+                      address valid_new_base, address valid_new_end, intx delta,
+                      CHeapBitMap* ptrmap = NULL) :
+    _patch_base(patch_base), _patch_end(patch_end),
+    _valid_old_base(valid_old_base), _valid_old_end(valid_old_end),
+    _valid_new_base(valid_new_base), _valid_new_end(valid_new_end),
+    _delta(delta) {
+    log_debug(cds, reloc)("SharedDataRelocator::_patch_base     = " PTR_FORMAT, p2i(_patch_base));
+    log_debug(cds, reloc)("SharedDataRelocator::_patch_end      = " PTR_FORMAT, p2i(_patch_end));
+    log_debug(cds, reloc)("SharedDataRelocator::_valid_old_base = " PTR_FORMAT, p2i(_valid_old_base));
+    log_debug(cds, reloc)("SharedDataRelocator::_valid_old_end  = " PTR_FORMAT, p2i(_valid_old_end));
+    log_debug(cds, reloc)("SharedDataRelocator::_valid_new_base = " PTR_FORMAT, p2i(_valid_new_base));
+    log_debug(cds, reloc)("SharedDataRelocator::_valid_new_end  = " PTR_FORMAT, p2i(_valid_new_end));
+    if (COMPACTING) {
+      assert(ptrmap != NULL, "must be");
+      _max_non_null_offset = 0;
+      _ptrmap = ptrmap;
+    } else {
+      // Don't touch the _max_non_null_offset and _ptrmap fields. Hopefully a good C++ compiler can
+      // elide them.
+      assert(ptrmap == NULL, "must be");
+    }
+  }
+
+  size_t max_non_null_offset() {
+    assert(COMPACTING, "must be");
+    return _max_non_null_offset;
+  }
+
+  inline bool do_bit(size_t offset);
+};
+
+
+#endif // SHARE_MEMORY_ARCHIVEUTILS_HPP