Re: [PATCH 01/12] gdb: add supports_arch_info callback to gdbarch_register

[Andrew Burgess <aburgess@redhat.com>]

Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

> From: Lancelot SIX <lancelot.six@amd.com>
>
> In the ROCm GDB port, there are some amdgcn architectures known by BFD
> that we don't actually support in GDB.  We don't want
> gdbarch_printable_names to return these architectures.
>
> gdbarch_printable_names is used for a few things:
>
>  - completion of the "set architecture" command
>  - the gdb.architecture_names function in Python
>  - foreach-arch selftests
>
> Add an optional callback to gdbarch_register that is a predicate
> indicating whether the gdbarch supports the given bfd_arch_info.  by
> default, it is nullptr, meaning that the gdbarch accepts all "mach"s for
> that architecture known by BFD.

LGTM.

Thanks,
Andrew

>
> Change-Id: I712f94351b0b34ed1f42e5cf7fc7ba051315d860
> Co-Authored-By: Simon Marchi <simon.marchi@efficios.com>
> ---
>  gdb/arch-utils.c | 9 +++++++--
>  gdb/gdbarch.h    | 4 +++-
>  2 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
> index 60ffdc5e16a..dbe78647d5e 100644
> --- a/gdb/arch-utils.c
> +++ b/gdb/arch-utils.c
> @@ -1211,6 +1211,7 @@ struct gdbarch_registration
>    enum bfd_architecture bfd_architecture;
>    gdbarch_init_ftype *init;
>    gdbarch_dump_tdep_ftype *dump_tdep;
> +  gdbarch_supports_arch_info_ftype *supports_arch_info;
>    struct gdbarch_list *arches;
>    struct gdbarch_registration *next;
>  };
> @@ -1234,7 +1235,9 @@ gdbarch_printable_names ()
>  	internal_error (_("gdbarch_architecture_names: multi-arch unknown"));
>        do
>  	{
> -	  arches.push_back (ap->printable_name);
> +	  if (rego->supports_arch_info == nullptr
> +	      || rego->supports_arch_info (ap))
> +	    arches.push_back (ap->printable_name);
>  	  ap = ap->next;
>  	}
>        while (ap != NULL);
> @@ -1247,7 +1250,8 @@ gdbarch_printable_names ()
>  void
>  gdbarch_register (enum bfd_architecture bfd_architecture,
>  		  gdbarch_init_ftype *init,
> -		  gdbarch_dump_tdep_ftype *dump_tdep)
> +		  gdbarch_dump_tdep_ftype *dump_tdep,
> +		  gdbarch_supports_arch_info_ftype *supports_arch_info)
>  {
>    struct gdbarch_registration **curr;
>    const struct bfd_arch_info *bfd_arch_info;
> @@ -1280,6 +1284,7 @@ gdbarch_register (enum bfd_architecture bfd_architecture,
>    (*curr)->bfd_architecture = bfd_architecture;
>    (*curr)->init = init;
>    (*curr)->dump_tdep = dump_tdep;
> +  (*curr)->supports_arch_info = supports_arch_info;
>    (*curr)->arches = NULL;
>    (*curr)->next = NULL;
>  }
> diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
> index f2ba5f97765..aea6c4335d9 100644
> --- a/gdb/gdbarch.h
> +++ b/gdb/gdbarch.h
> @@ -268,10 +268,12 @@ struct gdbarch_info
>  
>  typedef struct gdbarch *(gdbarch_init_ftype) (struct gdbarch_info info, struct gdbarch_list *arches);
>  typedef void (gdbarch_dump_tdep_ftype) (struct gdbarch *gdbarch, struct ui_file *file);
> +typedef bool (gdbarch_supports_arch_info_ftype) (const struct bfd_arch_info *);
>  
>  extern void gdbarch_register (enum bfd_architecture architecture,
>  			      gdbarch_init_ftype *init,
> -			      gdbarch_dump_tdep_ftype *dump_tdep = nullptr);
> +			      gdbarch_dump_tdep_ftype *dump_tdep = nullptr,
> +			      gdbarch_supports_arch_info_ftype *supports_arch_info = nullptr);
>  
>  
>  /* Return a vector of the valid architecture names.  Since architectures are
> -- 
> 2.38.1