Hi,

Patch for supporting multiple DWARF comp unit headers. This is necessary
for supporting DW_FORM_ref_addr properly when the reference is to a
compilation unit outside of the current one. The current code only
supports one comp unit at a time.

2002-07-03 Petr Sorfa (petrs@caldera.com)

        * dwarf2read.c (build_die_ref): New function that builds
          a new die reference if necessary, will search across
          multiple comp units to find the reference.
          (find_die_ref): New function that searches for a die
          reference for a given comp unit.
          (find_cu_header_from_begin_offset): New function that
          searches through a link list of comp unit headers for
          a comp unit that matches the given offset.
          (register_cu_header): New function that registers a
          comp unit header by allocating space for it and
          adding it to the comp unit header list.
          (free_cu_header_list): New function that frees up the
          memory taken up by the list of comp unit headers
          associated with a process.
          (dwarf_new_init): New function that initializes DWARF
          information for a new process.
          (struct comp_unit_head): Adds several new members
          to contain fully all the comp unit head's info.
          (first_cu_header): A new global variable that points
          to the first comp unit head for the process.
          (cu_header_offset): Global variable removed, as is now
          present in each comp unit head.
          (dwarf_abbrevs): Global variable removed, as is now
          present in each comp unit head.
          (dwarf2_read_abbrevs):
          (dwarf2_empty_abbrev_table):
          (dwarf2_lookup_abbrev):
          (dwarf_attr):
          (die_is_declaration):
          (read_base_type):
          (dwarf2_get_pc_bounds):
          (read_tag_string_type):
          (dwarf2_linkage_name):
          (dwarf2_get_ref_die_offset):
          All of these functions have a new argument added to
          pass the current comp unit header. All calls to these
          functions have been updated to handle the additional
          argument.

        * elfread.c (elf_new_init): Now calls dwarf_new_init()
          to initialize DWARF related information for the
          new process.