[RFC] Sort linetables in objfile_relocate.

[Klee Dienes <klee at apple dot com>]

When using objfile_relocate, if any of the entries in the linetable 
overflow or underflow, the linetable can end up unsorted.

The following patch adds code to objfile_relocate to handle the 
overflow/underflow case.  For efficiency, it special-cases for a 
linetable that was pre-sorted and then overflowed/underflowed, and just 
rotates the linetable in the linetable buffer for that case.  If the 
linetable wasn't pre-sorted, the sort code issues a warning and sorts 
it anyway using qsort().

Questions:

* Should it warn on the case where the objfile wasn't sorted before the 
relocation?  What about warning for overflow/underflow?

* Is the special-case code for a single overflow/underflow worth it?  
We could just use qsort() for everything.

* The qsort code needed compare_line_numbers to be exported from 
buildsym.c.  Wouldn't this be better named compare_line_addresses, or 
perhaps something else?

Attachment: sort-linetable.txt
Description: Text document