llvm dev - Oct 2021 - PowerPC LLVM support much appreciated

Hi,

Darwin support in PowerPC backend was deprecated in LLVM 8.0.0
(https://releases.llvm.org/8.0.0/docs/ReleaseNotes.html) and some was removed in
later releases. So you need an earlier LLVM version to generate code on Darwin
PowerPC, which may not be fully compatible with latest rustc.

Regards,
> Andrew Chiw via llvm-dev <llvm-dev at lists.llvm.org> wrote at
2021/10/21 5:01 AM:
> 
> Hello Iain,
> 
> Recently I decided to set myself the entirely alien task of getting Rust to
work on PowerPC Darwin (10.4/10.5). I mostly program in Python/Go and am a
newbie to Rust. Nevertheless, I've done some research and asked around on
LLVM discord and was told to direct my questions to you.
> 
> Being new to compiler/assembler development, could you fill me in on the
scope of this task I've just set myself?
> 
> The instructions here https://github.com/iains/darwin-toolchains-start-here
seem incomplete, and for someone who doesn't know much about compiler
development like me, I think it's missing quite a bit of context. Does it
work, would I get a LLVM which I could use to compile LLVM IR generated by
rustc?
> 
> Looking at the LLVM changelog, I have the impression that LLVM's major
versions don't change that much, so later versions of LLVM shouldn't be
too hard to get working either, am I correct?
> 
> What other roadblocks do you foresee? I was under the impression that I
only need to get LLVM to emit PowerPC MachO, but since then I have also heard
that I need to get Rust to work with 10.4/10.5's libc... which means both
language and compiling backend need to have access to the 10.4/10.5 libraries...
which means I shouldn't try to setup a cross compiler with my current state
of knowledge. More clarification/context much appreciated.
> 
> 
> Kind regards,
> 
> Andrew Chiw
> 
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> llvm-dev at lists.llvm.org
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Hello!

On 10/22/21 09:50, Qiu Chaofan via llvm-dev wrote:
> Darwin support in PowerPC backend was deprecated in LLVM 8.0.0 and some was
> removed in later releases. So you need an earlier LLVM version to generate
> code on Darwin PowerPC, which may not be fully compatible with latest
rustc.
I don't think it would take much to bring back support for Darwin/PowerPC as
long as the generic support for Darwin and PowerPC is still present in LLVM
and Rust.

I mean, we have support for M68k ;-).

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
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