[CFT] Update to clang 3.4

[Ed Maste]

On 7 January 2014 03:54, David Chisnall <theraven at freebsd.org> wrote:
> On 7 Jan 2014, at 06:49, Rui Paulo <rpaulo at FreeBSD.org> wrote:
>> Our libdwarf was a from scratch implementation and we never used the LGPL libdwarf.  I don't know if it's worth investing time upgrading our BSD licenced libdwarf or importing the LGPL libdwarf.  Given the push to keep the tree mostly BSD licenced, I would say the former.

I think bringing in a later version of elftoolchain / libdwarf would
be straightforward.  It seems there would be a fair amount of work
left even after doing that though.  Specifically, there's a todo item
for "Add support for DWARF4 ".debug_types" section":
sourceforge.net/apps/trac/elftoolchain/ticket/408.  There's still
ongoing development in elftoolchain, but I have no idea how likely it
is that a usable libdwarf will appear in the near future.  Perhaps
kaiw@ or jkoshy@ can comment.

> LLVM now has fairly complete DRAWF4 parsing support.  What interfaces do the ctf tools need, and are they the only consumers of libdwarf?

The ctf tools are indeed the only consumers of libdwarf, and all use
is in one file: cddl/contrib/opensolaris/tools/ctf/cvt/dwarf.c.  It
looks like it just parses various DW_TAG types (array, enum, pointer,
...) from .debug_info, and migrating to an LLVM DWARF parser wouldn't
be overly difficult.