add -fbounds-checking option.
When enabled, clang generates bounds checks for array and pointers dereferences. Work to follow in LLVM's backend.

OK'ed by Chad; thanks for the review.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156431 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed