RE: [PATCH 1/5] configure: check for libipt

["Metzger, Markus T" <markus.t.metzger@intel.com>]

> -----Original Message-----
> From: gdb-patches-owner@sourceware.org [mailto:gdb-patches-
> owner@sourceware.org] On Behalf Of Pedro Alves
> Sent: Tuesday, June 30, 2015 2:56 PM
> To: Metzger, Markus T
> Cc: gdb-patches@sourceware.org
> Subject: Re: [PATCH 1/5] configure: check for libipt
> 
> On 06/23/2015 09:16 AM, Markus Metzger wrote:
> > Check for libipt, an Intel(R) Processor Trace decoder library.  The sources
> > can be found on github at:
> >
> >     https://github.com/01org/processor-trace
> >
> > 2015-06-23  Markus Metzger  <markus.t.metzger@intel.com>
> >
> > 	* configure.ac: Check for libipt
> > 	* configure: Regenerate.
> > 	* config.in: Regenerate.
> > 	* Makefile.in (LIBIPT): New.
> > 	(CLIBS): Add $LIBIPT.
> 
> OK.
> 
> Is the library host independent?  That is, does it handle
> host vs target endianness, integer types, etc.?  E.g., is a big endian PPC
> host debugging against an x86-64 gdbserver able to use libipt?  Another
> example would be a big endian PPC host loading an x86-64 core dump that
> includes ipt data (once we get to it).

No.  It may not be too hard to make it work, though.  Most of the memory
accesses are byte-wise, already.

I don't have a PPC system to test this configuration.  Is this something
where Sergio's buildbot can help?  How is this cross-platform testing
usually handled?

Until libipt is available for PPC, you simply can't build a GDB with Intel PT
support on PPC.  When you configure GDB, HAVE_LIBIPT will be undefined
and GDB will fall back to BTS or report an error.  We're not breaking anything.
The feature will just not be available on all platforms.

Regards,
Markus.

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