[Bug bootstrap/56198] New: [4.8 Regression] Go profiledbootstrap error

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56198

             Bug #: 56198
           Summary: [4.8 Regression] Go profiledbootstrap error
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jakub@gcc.gnu.org
                CC: ian@gcc.gnu.org


My --enable-checking=release profiledbootstrap failed on an maybe uninitialized
warning turned into -Werror in go/gofrontend/import-archive.cc.
Archive_file::read_header has:
  off_t local_nested_off;
  if (!this->interpret_header(&hdr, off, pname, size, &local_nested_off))
    return false;
  if (nested_off != NULL)
    *nested_off = local_nested_off;
and the warning was complaining that local_nested_off might be uninitialized.
If Archive_file::interpret_header is what is called here, then *nested_off
might be indeed uninitialized even when the function returns true, in
particular for:
  else if (hdr->ar_name[1] == ' ')
    {
      // This is the symbol table.
      pname->clear();
    }
  else if (hdr->ar_name[1] == '/')
    {
      // This is the extended name table.
      pname->assign(1, '/');
    }
 BTW, there seems to be also an inconsistency in that method, the first write
to
*nested_off in that method is not guarded by nested_off != NULL:
      *nested_off = 0;
while the second one is:
      if (nested_off != NULL)
        *nested_off = y;