Hi Guys,

  I am checking in the attached patch to add support for the
  DW_AT_specification attribute in the BFD library's DWARF parser.  This
  has been prompted by gcc's --gdwarf-4 option which can now generate
  this attribute.

  The patch includes a new test, although it is rather picky.  It only
  works for 64-bit targets, and then not all of those either.  Ideally I
  should rewrite the test to be more generic but I will save that for
  another time.

Cheers
  Nick

bfd/ChangeLog
2020-03-19  Nick Clifton  <nickc@redhat.com>

	PR 25676
	* dwarf2.c (struct varinfo): Add unit_offset field to record the
	location of the varinfo in the unit's debug info data.  Change the
	type of the stack field to a boolean.
	(lookup_var_by_offset): New function.  Returns the varinfo
	structure for the variable described at the given offset in the
	unit's debug info.
	(scan_unit_for_symbols): Add support for variables which have the
	DW_AT_specification attribute.

binutils/ChangeLog
2020-03-19  Nick Clifton  <nickc@redhat.com>

	PR 25676
	* testsuite/binutils-all/dw4.s: New test source file.
	* testsuite/binutils-all/nm.exp: Run the new test.