Re: [RFA] New GDB target iq2000

[Jim Blandy <jimb@redhat.com>]

Hi, Corinna.

> +/* Function: gdbarch_init
> +   Initializer function for the iq2000 gdbarch vector.
> +   Called by gdbarch.  Sets up the gdbarch vector(s) for this target.  */
> +
> +static struct gdbarch *
> +iq2000_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> +{
> +  struct gdbarch *gdbarch;
> +
> +  /* Look up list for candidates - only one.  */
> +  arches = gdbarch_list_lookup_by_info (arches, &info);
> +  if (arches != NULL)
> +    return arches->gdbarch;
> +
> +  gdbarch = gdbarch_alloc (&info, NULL);
> +
> +  set_gdbarch_num_regs             (gdbarch, E_NUM_REGS);
> +  set_gdbarch_num_pseudo_regs      (gdbarch, 0);
> +  set_gdbarch_sp_regnum            (gdbarch, E_SP_REGNUM);
> +  set_gdbarch_pc_regnum            (gdbarch, E_PC_REGNUM);
> +  set_gdbarch_register_name        (gdbarch, iq2000_register_name);
> +  set_gdbarch_address_to_pointer   (gdbarch, iq2000_address_to_pointer);
> +  set_gdbarch_pointer_to_address   (gdbarch, iq2000_pointer_to_address);
> +  set_gdbarch_ptr_bit              (gdbarch, 4 * TARGET_CHAR_BIT);
> +  set_gdbarch_short_bit            (gdbarch, 2 * TARGET_CHAR_BIT);
> +  set_gdbarch_int_bit              (gdbarch, 4 * TARGET_CHAR_BIT);
> +  set_gdbarch_long_bit             (gdbarch, 4 * TARGET_CHAR_BIT);
> +  set_gdbarch_long_long_bit        (gdbarch, 8 * TARGET_CHAR_BIT);
> +  set_gdbarch_float_bit            (gdbarch, 4 * TARGET_CHAR_BIT);
> +  set_gdbarch_double_bit           (gdbarch, 8 * TARGET_CHAR_BIT);
> +  set_gdbarch_long_double_bit      (gdbarch, 8 * TARGET_CHAR_BIT);
> +  set_gdbarch_float_format         (gdbarch, & floatformat_ieee_single_big);
> +  set_gdbarch_double_format        (gdbarch, & floatformat_ieee_double_big);
> +  set_gdbarch_long_double_format   (gdbarch, & floatformat_ieee_double_big);
> +  set_gdbarch_return_value	   (gdbarch, iq2000_return_value);
> +  set_gdbarch_breakpoint_from_pc   (gdbarch, iq2000_breakpoint_from_pc);
> +  set_gdbarch_frame_args_skip      (gdbarch, 0);
> +  set_gdbarch_skip_prologue        (gdbarch, iq2000_skip_prologue);
> +  set_gdbarch_decr_pc_after_break  (gdbarch, 0);
> +  set_gdbarch_inner_than           (gdbarch, core_addr_lessthan);
> +  set_gdbarch_print_insn           (gdbarch, print_insn_iq2000);
> +  set_gdbarch_register_type (gdbarch, iq2000_register_type);
> +  set_gdbarch_frame_align (gdbarch, iq2000_frame_align);
> +  set_gdbarch_unwind_sp (gdbarch, iq2000_unwind_sp);
> +  set_gdbarch_unwind_pc (gdbarch, iq2000_unwind_pc);
> +  set_gdbarch_unwind_dummy_id (gdbarch, iq2000_unwind_dummy_id);
> +  frame_base_set_default (gdbarch, &iq2000_frame_base);
> +  set_gdbarch_push_dummy_call (gdbarch, iq2000_push_dummy_call);
> +
> +  gdbarch_init_osabi (info, gdbarch);
> +
> +  frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer);
> +  frame_unwind_append_sniffer (gdbarch, iq2000_frame_sniffer);
> +
> +  return gdbarch;
> +}

I think all the calls to set_gdbarch_<type>_bit can be left out,
because they just re-state the default values.  Same for
decr_pc_after_break, no?

+static enum return_value_convention
+iq2000_return_value (struct gdbarch *gdbarch, struct type *type,
+		     struct regcache *regcache,
+		     void *readbuf, const void *writebuf)
+{
+  if (iq2000_use_struct_convention (type))
+    return RETURN_VALUE_STRUCT_CONVENTION;
+  if (writebuf)
+    iq2000_store_return_value (type, regcache, writebuf);
+  else if (readbuf)
+    iq2000_extract_return_value (type, regcache, readbuf);
+  return RETURN_VALUE_REGISTER_CONVENTION;
+}

The other return_value implementations I've seen allow one to pass
both a readbuf and a writebuf, and do the read before the write.  I
can't find any place where it's actually used this way, but it seems
to be allowed by the interface.  In any case, it's easy enough to make
iq2000_return_value behave like the others.