[lldb-dev] Removing linux mips support

[Adrian Prantl via lldb-dev]

Sounds very reasonable to me.

thanks for bringing this up!
-- adrian

> On Mar 9, 2021, at 12:24 AM, Pavel Labath via lldb-dev <lldb-dev at lists.llvm.org> wrote:
> 
> Hi all,
> 
> I propose to remove support for linux mips debugging. This basically amounts to deleting source/Plugins/Process/Linux/NativeRegisterContextLinux_mips64.{cpp,h}. My reasons for doing that are:
> 
> - This code is unmaintained (last non-mechanical change was in 2017) and untested (no public buildbots), so we don't know if even basic functionality works, or if it indeed builds.
> 
> - At the same, it is carrying a lot of technical debt, which is leaking out of the mips-specific files, and interfering with other development efforts. The last instance of this is D96766, which is adding FreeBSD mips support, but needs to work around linux specific knowledge leaking into supposedly generic code. This one should be fixable relatively easily (these days we already have precedents for similar things in x86 and arm code), but it needs someone who is willing to do that.
> 
> But that is not all. To support mips, we introduced two new fields into the RegisterInfo struct (dynamic_size_dwarf_{expr_bytes,len}). These are introducing a lot of clutter in all our RegisterInfo definitions (which we have **a lot** of) and are not really consistent with the long term vision of the gdb-remote protocol usage in lldb. These days, we have a different mechanism for this (added to support a similar feature in arm), it would be better to implement this feature in terms of that. I would tout this (removal of these fields) as the main benefit of dropping mips support.
> 
> So, unless someone willing to address these issues (I'm happy to provide support where I can), I propose we drop mips support. Generic mips support will remain (and hopefully be better tested) thanks to the FreeBSD mips port, so re-adding mips support should be a matter of reimplementing the linux bits.
> 
> regards,
> Pavel
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