src/share/vm/memory/filemap.cpp

*** 467,494 ****
  // than one GC regions allocated for shared strings. 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 string
  // region. The rest are consecutive full GC regions if they exist, which can be written
  // out in one chunk as another string region.
! void FileMapInfo::write_string_regions(GrowableArray<MemRegion> *regions) {
    for (int i = MetaspaceShared::first_string;
             i < MetaspaceShared::first_string + MetaspaceShared::max_strings; i++) {
      char* start = NULL;
      size_t size = 0;
!     if (regions->is_nonempty()) {
        if (i == MetaspaceShared::first_string) {
          MemRegion first = regions->first();
          start = (char*)first.start();
          size = first.byte_size();
        } else {
!         int len = regions->length();
          if (len > 1) {
            start = (char*)regions->at(1).start();
            size = (char*)regions->at(len - 1).end() - start;
          }
        }
      }
      write_region(i, start, size, false, false);
    }
  }
  
  
--- 467,531 ----
  // than one GC regions allocated for shared strings. 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 string
  // region. The rest are consecutive full GC regions if they exist, which can be written
  // out in one chunk as another string region.
! //
! // Here's the mapping from (GrowableArray<MemRegion> *regions) -> (metaspace string regions).
! //   + We have 1 or more heap regions: r0, r1, r2 ..... rn
! //   + We have 2 metaspace string regions: s0 and s1
! //
! // If there's a single heap region (r0), then s0 == r0, and s1 is empty.
! // Otherwise:
! //
! // "X" represented space that's occupied by heap objects.
! // "_" represented unused spaced in the heap region.
! //
! //
! //    |r0        | r1  | r2 | ...... | rn |
! //    |XXXXXX|__ |XXXXX|XXXX|XXXXXXXX|XXXX|
! //    |<-s0->|   |<- s1 ----------------->|
! //            ^^^
! //             |
! //             +-- unmapped space
! void FileMapInfo::write_string_regions(GrowableArray<MemRegion> *regions,
!                                        char** st0_start, char** st0_top, char** st0_end,
!                                        char** st1_start, char** st1_top, char** st1_end) {
!   *st0_start = *st0_top = *st0_end = NULL;
!   *st1_start = *st1_top = *st1_end = NULL;
! 
!   assert(MetaspaceShared::max_strings == 2, "this loop doesn't work for any other value");
    for (int i = MetaspaceShared::first_string;
             i < MetaspaceShared::first_string + MetaspaceShared::max_strings; i++) {
      char* start = NULL;
      size_t size = 0;
!     int len = regions->length();
!     if (len > 0) {
        if (i == MetaspaceShared::first_string) {
          MemRegion first = regions->first();
          start = (char*)first.start();
          size = first.byte_size();
+         *st0_start = start;
+         *st0_top = start + size;
+         if (len > 1) {
+           *st0_end = (char*)regions->at(1).start();
          } else {
!           *st0_end = start + size;
!         }
!       } else {
!         assert(i == MetaspaceShared::first_string + 1, "must be");
          if (len > 1) {
            start = (char*)regions->at(1).start();
            size = (char*)regions->at(len - 1).end() - start;
+           *st1_start = start;
+           *st1_top = start + size;
+           *st1_end = start + size;
          }
        }
      }
+     log_info(cds)("String 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);
    }
  }