Re: Specifying target endianness via Remote Serial Protocol

[Omer <omerg681@gmail.com>]

Will older gdb's really break if we send them fields they don't know? The
logical thing to do seems to me to just to discard them.
I want to use remote gdb without giving it an elf to work with locally (for
example if I want to debug some weird embedded system).
I can somewhat circumvent the problem by giving gdb an empty elf with my
wanted endianness, but I don't think it's the optimal solution.

On Mon, 13 Apr 2020 at 16:04, Luis Machado <luis.machado@linaro.org> wrote:

> Hi,
>
> On 4/12/20 9:02 AM, Omer via Gdb wrote:
> > Hi,
> >
> > While writing my own gdb stub, I noticed that there is no way to specify
> > what endianness the target is using (I guess the logical place for that
> > would be in the target.xml file).
> > One can use "set endian" manually to fix that, but when debugging an ARM
> > BE8 target, there is no way to specify that the code is little endian
> > (currently byte_order_for_code is initialized to little only when
> loading a
> > BE8 elf).
> > Shouldn't there be an additional field for target XML tag to specify
> that?
>
> We could probably extend the XML descriptions to incorporate this, but
> we may also have backwards compatibility issues with older GDB's by
> returning new fields the target doesn't know how to parse properly.
>
> The way to fix this, right now, would be to teach GDB about other arch
> variations using little endian, so GDB initializes the proper set of
> architecture hooks and types.
>
> What arch variation are you working with? Doesn't the tools generate a
> EF_ARM_BE8 flag to let GDB know it needs to assume little endian?
>