This object controls when the warnings are executed, allowing the client code
in Sema to selectively disable warnings as needed.
Centralizing the logic for analysis-based warnings allows us to optimize
when and how they are run.
Along the way, remove the redundant logic for the 'check fall-through' warning
for blocks; now the same logic is used for both blocks and functions.
llvm-svn: 99085
Ted Kremenek