Re: [PATCH, updated] Add support for setting disassembler-options in GDB for POWER, ARM and S390

[Pedro Alves <palves at redhat dot com>]

On 02/13/2017 03:52 PM, Yao Qi wrote:
> These options should be modeled as per-architecture data.  We need to
> define a key to access that data dynamically.  grep
> "static struct gdbarch_data *" in *.c.

If I understand the suggestion correctly, that would make all the different
POWER (etc.) gdbarch instances have their own instance of the option string.
I.e., the POWER gdbarch instance determined for the objfile before the program
is run or GDB connects to a target would have a different set of options than
the gdbarch instance created based on the POWER-based XML target description
returned by the (e.g.), remote server, because those are different
gdbarch object instances.  As a result "set disassembler-options" would
show different options before and after run/connection (and in other
situations that use different gdbarch objects).

What Alan's implementation achieves instead is that there's only one option
value string for the whole family of gdbarchs of a given architecture, like
POWER vs MIPS, vs x86, etc, so that the disassembler options active persist
across internal uses of all the different gdbarch instances that
model variants of the same CPU architecture.

Thanks,
Pedro Alves