[RegionInfo] Add debug-time region viewer functions
Summary:
Analogously to Function::viewCFG(), RegionInfo::view() and RegionInfo::viewOnly() are meant to be called in debugging sessions. They open a viewer to show how RegionInfo currently understands the region hierarchy.
The functions viewRegion(Function*) and viewRegionOnly(Function*) invoke a fresh region analysis of the function in contrast to viewRegion(RegionInfo*) and viewRegionOnly(RegionInfo*) which show the current analysis result.
Reviewers: grosser
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11875
llvm-svn: 244444