as: Linkonce

 
 7.54 '.linkonce [TYPE]'
 =======================
 
 Mark the current section so that the linker only includes a single copy
 of it.  This may be used to include the same section in several
 different object files, but ensure that the linker will only include it
 once in the final output file.  The '.linkonce' pseudo-op must be used
 for each instance of the section.  Duplicate sections are detected based
 on the section name, so it should be unique.
 
    This directive is only supported by a few object file formats; as of
 this writing, the only object file format which supports it is the
 Portable Executable format used on Windows NT.
 
    The TYPE argument is optional.  If specified, it must be one of the
 following strings.  For example:
      .linkonce same_size
    Not all types may be supported on all object file formats.
 
 'discard'
      Silently discard duplicate sections.  This is the default.
 
 'one_only'
      Warn if there are duplicate sections, but still keep only one copy.
 
 'same_size'
      Warn if any of the duplicates have different sizes.
 
 'same_contents'
      Warn if any of the duplicates do not have exactly the same
      contents.