--- old/src/share/vm/memory/filemap.cpp	2017-08-08 17:40:44.576317019 -0400
+++ new/src/share/vm/memory/filemap.cpp	2017-08-08 17:40:43.260242224 -0400
@@ -461,22 +461,25 @@
   write_bytes_aligned(base, (int)size);
 }
 
-// Write the current archive heap region, which contains one or multiple GC(G1) regions.
-// When current archive heap region size is smaller than one GC region of the dump time,
-// all archive heap data is written out as one region.
-//
-// If the current archive heap region size is bigger than one GC region, there would be more
-// than one GC regions allocated for archive heap data. The first/bottom GC region might
-// be a partial GC region with the empty portion at the higher address within that region.
-// The non-empty portion of the first region is written into the archive as one archive
-// region. The rest are consecutive full GC regions if they exist, which can be written
-// out in one chunk as another archive region.
+// Write out the given archive heap memory regions.  GC code combines multiple
+// consequetive archive GC regions into one MemRegion whenever possible and
+// produces the 'heap_mem' array. 
 //
-// Here's the mapping from (archive heap regions) -> (GrowableArray<MemRegion> *regions).
+// If the archive heap memory size is smaller than a single dump time GC region
+// size, there is only one MemRegion in the array.
+//
+// If the archive heap memory size is bigger than one dump time GC region size,
+// the 'heap_mem' array may contain more than one consolidated MemRegions. When
+// the first/bottom archive GC region is a partial GC region(with the empty
+// portion at the higher address within the region), one MemRegion is used for
+// the bottom partial archive GC region. The rest of the consqusective archive
+// GC regions are combined into another MemRegion.
+//
+// Here's the mapping from (archive heap GC regions) -> (GrowableArray<MemRegion> *regions).
 //   + We have 1 or more archive heap regions: ah0, ah1, ah2 ..... ahn
-//   + We have 2 consolidate heap memory regions: r0 and r1
+//   + We have 1 or 2 consolidated heap memory regions: r0 and r1
 //
-// If there's a single archive heap region (ah0), then r0 == ah0, and r1 is empty.
+// If there's a single archive GC region (ah0), then r0 == ah0, and r1 is empty.
 // Otherwise:
 //
 // "X" represented space that's occupied by heap objects.
@@ -489,37 +492,33 @@
 //            ^^^
 //             |
 //             +-- gap
-void FileMapInfo::write_archive_heap_regions(GrowableArray<MemRegion> *regions,
-                                             int first_region, int max_num_regions,
-                                             char** r0_start, char** r0_top,
-                                             char** r1_start, char** r1_top) {
-  int arr_len = regions == NULL ? 0 : regions->length();
-  assert(max_num_regions <= 2, "this loop doesn't work for any other value");
-  assert(arr_len <= max_num_regions, "number of memory regions exceeds maximum");
-
-  *r0_start = *r0_top = NULL;
-  *r1_start = *r1_top = NULL;
-
-  for (int i = first_region, arr_idx = 0; i < first_region + max_num_regions; i++, arr_idx++) {
+size_t FileMapInfo::write_archive_heap_regions(GrowableArray<MemRegion> *heap_mem,
+                                               int first_region_id, int max_num_regions) {
+  assert(max_num_regions <= 2, "Only support maximum 2 memory regions");
+
+  int arr_len = heap_mem == NULL ? 0 : heap_mem->length();
+  if(arr_len > max_num_regions) {
+    fail_stop("Unable to write archive heap memory regions: "
+              "number of memory regions exceeds maximum due to fragmentation");
+  } 
+
+  size_t total_size = 0;
+  for (int i = first_region_id, arr_idx = 0;
+           i < first_region_id + max_num_regions;
+           i++, arr_idx++) {
     char* start = NULL;
     size_t size = 0;
     if (arr_idx < arr_len) {
-      start = (char*)regions->at(arr_idx).start();
-      size = regions->at(arr_idx).byte_size();
-    }
-    if (i == first_region) {
-      *r0_start = start;
-      *r0_top = start + size;
-    } else {
-      assert(i == first_region + 1, "must be");
-      *r1_start = start;
-      *r1_top = start + size;
+      start = (char*)heap_mem->at(arr_idx).start();
+      size = heap_mem->at(arr_idx).byte_size();
+      total_size += size;
     }
 
     log_info(cds)("Archive heap region %d " INTPTR_FORMAT " - " INTPTR_FORMAT " = " SIZE_FORMAT_W(8) " bytes",
                   i, p2i(start), p2i(start + size), size);
     write_region(i, start, size, false, false);
   }
+  return total_size;
 }
 
 // Dump bytes to file -- at the current file position.
@@ -687,7 +686,7 @@
 // the references are updated by GC.
 //
 void FileMapInfo::map_heap_regions() {
-  if (MetaspaceShared::allow_archive_heap_object()) {
+  if (MetaspaceShared::is_heap_object_archiving_allowed()) {
     // Check that all the narrow oop and klass encodings match the archive
     if (narrow_oop_mode() != Universe::narrow_oop_mode() ||
         narrow_oop_shift() != Universe::narrow_oop_shift() ||
@@ -734,7 +733,7 @@
   }
 }
 
-bool FileMapInfo::map_heap_data(MemRegion **mem_regions, int first,
+bool FileMapInfo::map_heap_data(MemRegion **heap_mem, int first,
                                 int max, int* num, bool is_open_archive) {
   MemRegion * regions = new MemRegion[max];
   struct FileMapInfo::FileMapHeader::space_info* si;
@@ -805,7 +804,7 @@
   }
 
   // the shared heap data is mapped successfully
-  *mem_regions = regions;
+  *heap_mem = regions;
   *num = region_num;
   return true;
 }