[LLVMdev] Add support for ldr pseudo instruction in ARM integrated assembler

[Renato Golin]

So, it seems there are enough people on the plus side, I just wanted to
make sure we evaluate all sides before taking a decision to add syntactic
sugar to LLVM assembler.

My main concern is still the same as earlier this year: the integrated
assembler for ARM is still not complete, and the more extensions we add to
the back-end, the harder it'll be to get it into production quality.

That said...


On 27 October 2013 01:02, Chris Lattner <clattner at apple.com> wrote:

> I agree.  These pseudo instructions seem like pure syntactic sugar that
> should never be produced by the disassembler.  That doesn't make them bad,
> in fact it makes them simpler to implement and reason about.
>


I agree with this line of thought, though it's not necessarily simple to
implement this specific one, because of the constant pools. You have to pay
attention if there aren't many pools next to each other, or where is the
best placement (due to proximity, relocations, alignment), etc. I'm not
sure we've got all that logic already in, so this patch might end up a lot
bigger than just adding a few parser lines.

Ultimately, I'm not against it, but I'd be a lot more comfortable if I saw
lots of tests and lots of people looking at it (from different angles),
just to make sure we're not missing anything obvious and introducing major
regressions because of syntactic sugar.

cheers,
--renato
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