Re: RFA: relax restrictions on per-architecture data registration

[Jim Blandy <jimb at zwingli dot cygnus dot com>]

Andrew Cagney <ac131313@cygnus.com> writes:
> > 2001-06-01  Jim Blandy  <jimb@redhat.com>
> > 
> > Expand the gdbarch per-architecture data vector as needed, rather
> > 	than requiring that all per-architecture data be registered before
> > 	the first gdbarch object is allocated.
> > 	* gdbarch.sh: Changes to effect the following:
> > 	* gdbarch.c (alloc_gdbarch_data, init_gdbarch_data): Delete
> > 	declarations and definitions.
> > 	(check_gdbarch_data): New function, and declaration.
> > 	(gdbarch_alloc): Don't call alloc_gdbarch_data; leaving the fields
> > 	zero is good enough.
> > 	(free_gdbarch_data): Tolerate a null data pointer.  Free only
> > 	those data items gdbarch->data actually has allocated.
> > 	(set_gdbarch_data, gdbarch_data): Call check_gdbarch_data.
> > 	(gdbarch_update_p): No need to call init_gdbarch_data.
> 
> I think this is wrong.  GDB's startup sequence is currently something like:
> 
> 	o	_initialize_*() registers any
> 		per-architecture data
> 
> 	o	GDB creates the initial architecture
> 
> So that data buffer size would never change.
> 
> To follow up my previous post.  All I think is needed is for the code in 
> arch-utils.c:initialize_current_architecture():
> 
> 
>    if (GDB_MULTI_ARCH)
>      {
>        if (! gdbarch_update_p (info))
>          {
>            internal_error (__FILE__, __LINE__,
>                            "initialize_current_architecture: Selection 
> of initial architecture
> failed");
>          }
>      }
> 
> to be tweeked so that, when there is no multi-arch, the data vector is 
> still initialized.

Okay.  My first patch was exactly that, but then I felt like I was
assuming that all per-architecture data would be registered by the
time initialization was done, which wasn't a documented requirement in
gdbarch.h.  So I made it more dynamic.

I'll revert my patch, and post a new one shortly.