Simplify the logic for DNBDataRef::ValidOffsetForDataOfSize() and DNBDataRef::ValidOffset() functions.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@177615 91177308-0d34-0410-b5e6-96231b3b80d8
Fixed the ValidOffsetForDataOfSize() to use simpler logic. Fixed DataExtractor::BytesLeft() to return the correct value.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@177616 91177308-0d34-0410-b5e6-96231b3b80d8
Added a lldb-perf test case that will be used to time various aspects of debugging clang with LLDB.

This test case will measure memory usage and expression timings in frame zero and at higher frames.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@177617 91177308-0d34-0410-b5e6-96231b3b80d8