>The frame's CFA is the basis for identifying the frame and locating
>saved registers in the CFI. It is always present when you have CFI.
>
>DW_AT_frame_base is the basis for locating saved variables and locals.
>It is generally present when you have DWARF-2 debug info.
You and I went through all this not too long ago. frame-base is for
this high level thingie, frame-unwind is for the low level register
information.
Then, as Mark said, it shouldn't be providing a frame base at all. The
CFA information is not the right frame base, and the use of
DW_AT_frame_base is exactly orthogonal to the use of CFI.