[llvm-dev] RFC: On removing magic numbers assuming 8-bit bytes
Philip Reames via llvm-dev
llvm-dev at lists.llvm.org
Mon May 6 15:56:49 PDT 2019
On 5/6/19 2:43 AM, Tim Northover via llvm-dev wrote:
> On Mon, 6 May 2019 at 10:13, James Courtier-Dutton via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
>> Although the above is mentioning bytes, looking at the "/ 8" and "& 0x7" makes it look like the author meant octets and not bytes.
>> Bytes can be any size of bits.
> I don't think you'll have much luck trying to make that stick for a
> general audience, or even a general compiler-writer audience. Byte is
> far too strongly associated with 8 bits these days.
+1 Please don't try; insisting on a distinction will confuse many new
>> Octets are only ever 8 bits.
> You might be able to convert all uses of byte to octet and abandon
> byte entirely, but at that point why bother? It feels like a change
> just for the sake of pedantry.
> I like the "addressable unit" name, though it's a bit long (AddrUnit
> seems OK). It at least signals to a reader that there might be
> something weird going on. Getting someone writing new code to think in
> those terms is a different matter, of course, but I don't think any of
> the changes under discussion really help there.
> BTW, is there an open source backend (in a fork, I assume) that does
> this? So that we can get some kind of idea of the real scope of the
> changes needed.
My personal take is this is an invasive enough change with enough likely
ongoing maintenance fall out to require substantial justification before
the work was undertaken upstream. A open source backend proposed for
inclusion upstream would be one part of that. Active contribution from
the sponsors in other areas would also be a key factor.
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