Define an error function in the PPC simulator.

  Previously this used the error function from GDB directly instead of
the error method in the host callbacks structure.  This was exposed via
a link error when GDB was converted to C++.  The error function invokes
the error callback similar to sim_io_error.

sim/ppc/ChangeLog:

	* sim_calls.c (error): New function.
---
 sim/ppc/ChangeLog   |  4 ++++
 sim/ppc/sim_calls.c | 10 ++++++++++
 2 files changed, 14 insertions(+)
  

On 24 Nov 2016 07:29, John Baldwin wrote:
> Previously this used the error function from GDB directly instead of
> the error method in the host callbacks structure.  This was exposed via
> a link error when GDB was converted to C++.  The error function invokes
> the error callback similar to sim_io_error.

ppc/main.c and ppc/misc.c already have error() definitions
-mike
  

On Friday, November 25, 2016 08:49:08 AM Mike Frysinger wrote:
> On 24 Nov 2016 07:29, John Baldwin wrote:
> > Previously this used the error function from GDB directly instead of
> > the error method in the host callbacks structure.  This was exposed via
> > a link error when GDB was converted to C++.  The error function invokes
> > the error callback similar to sim_io_error.
> 
> ppc/main.c and ppc/misc.c already have error() definitions

Yes, though those are not included when libsim is linked into gdb itself.
misc.o is explicitly included for certain binaries in sim/ppc/Makefile.in.
Note that zalloc() is defined in both misc.c and sim_calls.c as well, I
suspect for similar reasons.

Looking at main.c, it overrides various symbols (sim_io_*, also
zalloc) that are defined in sim_calls.c with local versions.  (Perhaps
psim should not be linking sim_calls.o in at all?)  'error' is another
such symbol.
  

On 25 Nov 2016 09:21, John Baldwin wrote:
> On Friday, November 25, 2016 08:49:08 AM Mike Frysinger wrote:
> > On 24 Nov 2016 07:29, John Baldwin wrote:
> > > Previously this used the error function from GDB directly instead of
> > > the error method in the host callbacks structure.  This was exposed via
> > > a link error when GDB was converted to C++.  The error function invokes
> > > the error callback similar to sim_io_error.
> > 
> > ppc/main.c and ppc/misc.c already have error() definitions
> 
> Yes, though those are not included when libsim is linked into gdb itself.
> misc.o is explicitly included for certain binaries in sim/ppc/Makefile.in.
> Note that zalloc() is defined in both misc.c and sim_calls.c as well, I
> suspect for similar reasons.
> 
> Looking at main.c, it overrides various symbols (sim_io_*, also
> zalloc) that are defined in sim_calls.c with local versions.  (Perhaps
> psim should not be linking sim_calls.o in at all?)  'error' is another
> such symbol.

yes, the ppc sim is a bit of mess due to its history.  i'm not sure we
should just keep throwing onto the pile though.

if psim/main.c doesn't need it, then dropping it sounds easy enough.
-mike
  

On Saturday, November 26, 2016 02:19:46 PM Mike Frysinger wrote:
> On 25 Nov 2016 09:21, John Baldwin wrote:
> > On Friday, November 25, 2016 08:49:08 AM Mike Frysinger wrote:
> > > On 24 Nov 2016 07:29, John Baldwin wrote:
> > > > Previously this used the error function from GDB directly instead of
> > > > the error method in the host callbacks structure.  This was exposed via
> > > > a link error when GDB was converted to C++.  The error function invokes
> > > > the error callback similar to sim_io_error.
> > > 
> > > ppc/main.c and ppc/misc.c already have error() definitions
> > 
> > Yes, though those are not included when libsim is linked into gdb itself.
> > misc.o is explicitly included for certain binaries in sim/ppc/Makefile.in.
> > Note that zalloc() is defined in both misc.c and sim_calls.c as well, I
> > suspect for similar reasons.
> > 
> > Looking at main.c, it overrides various symbols (sim_io_*, also
> > zalloc) that are defined in sim_calls.c with local versions.  (Perhaps
> > psim should not be linking sim_calls.o in at all?)  'error' is another
> > such symbol.
> 
> yes, the ppc sim is a bit of mess due to its history.  i'm not sure we
> should just keep throwing onto the pile though.
> 
> if psim/main.c doesn't need it, then dropping it sounds easy enough.

I misread the Makefiles a bit and psim doesn't link in sim_calls.o, so it
still needs its own zalloc() and error() in main.c.

In particular, ppc/Makefile generates the libsim.a that gdb links against
which includes sim_calls.o (via GDB_OBJ) but not main.o or misc.o.  The
psim binary includes main.o (but not sim_calls.o or misc.o), and the other
binaries (igen, dgen, tmp-filter) include misc.o (but not sim_calls.o or
main.o).

While it might make sense to merge bits of main.c with misc.c, I think the
GDB-specific functions in sim_calls.c are always going to be required
(including a custom error() that invokes GDB's error hook).
  

On Tuesday, December 06, 2016 11:08:07 AM John Baldwin wrote:
> On Saturday, November 26, 2016 02:19:46 PM Mike Frysinger wrote:
> > On 25 Nov 2016 09:21, John Baldwin wrote:
> > > On Friday, November 25, 2016 08:49:08 AM Mike Frysinger wrote:
> > > > On 24 Nov 2016 07:29, John Baldwin wrote:
> > > > > Previously this used the error function from GDB directly instead of
> > > > > the error method in the host callbacks structure.  This was exposed via
> > > > > a link error when GDB was converted to C++.  The error function invokes
> > > > > the error callback similar to sim_io_error.
> > > > 
> > > > ppc/main.c and ppc/misc.c already have error() definitions
> > > 
> > > Yes, though those are not included when libsim is linked into gdb itself.
> > > misc.o is explicitly included for certain binaries in sim/ppc/Makefile.in.
> > > Note that zalloc() is defined in both misc.c and sim_calls.c as well, I
> > > suspect for similar reasons.
> > > 
> > > Looking at main.c, it overrides various symbols (sim_io_*, also
> > > zalloc) that are defined in sim_calls.c with local versions.  (Perhaps
> > > psim should not be linking sim_calls.o in at all?)  'error' is another
> > > such symbol.
> > 
> > yes, the ppc sim is a bit of mess due to its history.  i'm not sure we
> > should just keep throwing onto the pile though.
> > 
> > if psim/main.c doesn't need it, then dropping it sounds easy enough.
> 
> I misread the Makefiles a bit and psim doesn't link in sim_calls.o, so it
> still needs its own zalloc() and error() in main.c.
> 
> In particular, ppc/Makefile generates the libsim.a that gdb links against
> which includes sim_calls.o (via GDB_OBJ) but not main.o or misc.o.  The
> psim binary includes main.o (but not sim_calls.o or misc.o), and the other
> binaries (igen, dgen, tmp-filter) include misc.o (but not sim_calls.o or
> main.o).
> 
> While it might make sense to merge bits of main.c with misc.c, I think the
> GDB-specific functions in sim_calls.c are always going to be required
> (including a custom error() that invokes GDB's error hook).

*ping* (This fixes PR sim/20863 btw)