Hi,

this is based on Andrew's patch here:

https://sourceware.org/ml/gdb-patches/2020-02/msg00092.html

This and adds a heuristic to fix the case where caller
and callee reside in the same subfile, it uses
the recorded is-stmt bits and locates end of
range infos, including the previously ignored empty
range, and adjusting is-stmt info at this
same pc, when the last item is not-is-stmt, the
previous line table entries are dubious and
we reset the is-stmt bit there.
This fixes the new test case in Andrew's patch.

It understood, that this is just a heuristic
approach, since we do not have exactly the data,
which is needed to determine at which of the identical
PCs in the line table the subroutine actually ends.
So, this tries to be as conservative as possible,
just changing what is absolutely necessary.

This patch itself is preliminary, since the is-stmt patch
needs to be rebased after the refactoring of
dwarf2read.c from yesterday, so I will have to rebase
this patch as well, but decided to wait for Andrew.


Thanks
Bernd.