This is a script to extract nodes and edges associated with those nodes

This is a script to extract nodes and edges associated with those nodes
from a dot file that is the output of DSA.  Nodes to extract
are specified by giving the name of the node seen in the graphical
representation, i.e. in the .ps if the node is specified %xyz
asking for just x, xy, or xyz will retain it in the output file.
Because it operates on substrings underspecifying may result
in additional unexpected nodes.  Be as specific as possible.
Obviously, however, if you ask for %xyz and there is a
getelementptr of %xyz you will get both nodes.  Some manual
editing may still be necessary because of this, but this script
can pare down 10,000 line files to 20 line files, making like easier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24851 91177308-0d34-0410-b5e6-96231b3b80d8