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Re: [PATCH, RFC] Add support for choosing disassembler cpu in GDB for POWER.
- From: "Ulrich Weigand" <uweigand at de dot ibm dot com>
- To: bergner at vnet dot ibm dot com (Peter Bergner)
- Cc: palves at redhat dot com (Pedro Alves), amodra at gmail dot com (Alan Modra), gdb-patches at sourceware dot org, binutils at sourceware dot org (binutils)
- Date: Fri, 7 Oct 2016 21:21:06 +0200 (CEST)
- Subject: Re: [PATCH, RFC] Add support for choosing disassembler cpu in GDB for POWER.
- Authentication-results: sourceware.org; auth=none
Peter Bergner wrote:
> * gdbarch.sh (target_disassemble_init): New.
> * gdbarch.c: Regenerate.
> * gdbarch.h: Likewise.
> * disasm.c (gdb_disassemble_info): Call gdbarch_target_disassemble_init.
> * rs6000-tdep.c: Include "opcode/ppc.h".
> (gdb_disassembler_cpu): New static declaration.
> (prospective_cpu): Likewise.
> (gdb_rs6000_init_disassembly): New function.
> (set_disassembler_cpu): Likewise.
> (show_disassembler_cpu): Likewise.
> (rs6000_gdbarch_init): Setup callback for gdb_rs6000_init_disassembly.
> (_initialize_rs6000_tdep): Initialize gdb_disassembler_cpu and
> target_init_disassembly. Setup callbacks for set_disassembler_cpu()
> and show_disassembler_cpu().
I like this a lot better than the original patch :-)
Still some comments:
> @@ -785,6 +785,8 @@ gdb_disassemble_info (struct gdbarch *gdbarch, struct ui_file *file)
> di.endian = gdbarch_byte_order (gdbarch);
> di.endian_code = gdbarch_byte_order_for_code (gdbarch);
> di.application_data = gdbarch;
> + if (gdbarch_target_disassemble_init_p (gdbarch))
> + gdbarch_target_disassemble_init (gdbarch, &di);
> disassemble_init_for_target (&di);
> return di;
There's a second use of disassemble_init_for_target, which probably needs
the same treatment. In fact, maybe the nicest way would be to call the
callback "gdbarch_disassemble_init_for_target", with a default of simply
disassemble_init_for_target, but which targets can override to do extra
stuff before (or after) calling disassemble_init_for_target in there.
GDB common code would then just call gdbarch_disassemble_init_for_target
everywhere it currently calls disassemble_init_for_target.
> + gdb_disassembler_cpu = strdup (PPC_DEFAULT_CPU",any");
Why do we have to know about this here in GDB? Can't the GDB default just
be the empty (or NULL) string, and then opcodes does the defaulting
(as it does today)?
Dr. Ulrich Weigand
GNU/Linux compilers and toolchain