Summary:
This patch introduces a new testing utility for building and modifying CFG -- CFGBuilder. The primary use case for the utility is testing the upcoming incremental dominator tree update API.
The current design provides a simple mechanism of constructing arbitrary graphs and then applying series of updates to them. CFGBuilder takes care of creating empty functions, connecting and disconnecting basic blocks. Under the hood it uses SwitchInst and UnreachableInst.
It will be also possible to create a thin wrapper over CFGBuilder for parsing string input and to hook it up to other textual tools (e.g. opt used with FileCheck).
Reviewers: dberlin, sanjoy, grosser, dblaikie
Reviewed By: dblaikie
Subscribers: davide, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D34798
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307960 91177308-0d34-0410-b5e6-96231b3b80d8
