Hi,

There are cases when gcc outputs a valid DWARF register number in a
DWARF expression, but gdb can't access that register.  In theory this is
a generic problem, but the specific case I'm interested in is debugging
ARM VFP code on Linux with a kernel prior to 2.6.30. In this case ptrace
does not expose the contents of a processes' VFP registers although gcc
accurately describes the location of floating point values as being in
the VFP registers.

If you try to access such a DWARF register number gdb reports an
internal error.

The attached patch changes these internal errors into warnings, and
tries to return something sensible to the user.

Please could someone review and comment on the patch, and then if this
is approved can they please commit it as I don't have commit rights.

Suggested ChangeLog:

2010-04-26  Matthew Gretton-Dann  <matthew.gretton-dann@arm.com>

	* dwarf2loc.c (read_pieced_value, write_pieced_value,
	dwarf2_evaluate_loc_desc): Handle not being able to access DWARF
	registers gracefully.

Thanks,

Matt

-- 
Matthew Gretton-Dann
Principal Engineer - Tools, PD Software
ARM Limited