ogle/program: in stack frames, add the function name, parameters, and local variables.

A program.Var is returned for each parameter and variable, so we can use
Value to get their values.  evalLocation is changed to return an error
when it can't parse a DWARF location description.  Parameters and
variables we can't parse are ignored.

Fixes some error messages.

Change-Id: I0bd4263268db01cf206fdc8e1f1d55b9106035c6
Reviewed-on: https://go-review.googlesource.com/10609
Reviewed-by: Rob Pike <r@golang.org>
5 files changed