[DynInst_API:] [dyninst/dyninst] 15459e: Correctness fixes for springboard generators

[Benjamin Welton <noreply@xxxxxxxxxx>]

  Branch: refs/heads/dev-552
  Home:   https://github.com/dyninst/dyninst
  Commit: 15459e9ad06b9b907a3a99a2b9481020ab2fdf06
      https://github.com/dyninst/dyninst/commit/15459e9ad06b9b907a3a99a2b9481020ab2fdf06
  Author: Benjamin Welton <welton@xxxxxxxxxxx>
  Date:   2019-03-20 (Wed, 20 Mar 2019)

  Changed paths:
    M dyninstAPI/src/Relocation/Springboard.C

  Log Message:
  -----------
  Correctness fixes for springboard generators

This patch deals with issues where incorrect springboards could be generated.
Specifically addresses three issues:

1. Springboards trampling function data (addresses github issue #551)

2. Required springboards being spilling over block bounds onto
   other required springboards. Prior a if two required springboards were
   located near each other, there was a chance that one of the springboards
   could be partially overwritten resulting in broken behavior.

3. Unsafe reusage of a codegen object where if a trap was needed,
   both a branch and a trap would be written causing bad behavior.