llvm dev - Aug 2010 - [LLVMdev] Where can I find an explanation of $src1, $src2, $in, $ptr, etc.?

I have read through the TableGen Fundamentals documentation and been
browsing various .td files. One thing that is not clear to me is where
things like $src1 (as in GR32:$src1) are defined, and what they mean. The
TableGen Fundamentals page seems silent on this, and I have not found other
documentation that explains it. Browsing through the .td files has not
helped, either (although that has been quite useful to clarify things that
are not spelled out in detail on the TableGen Fundamentals page).

Thanks,

Mark
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On Aug 16, 2010, at 7:24 PM, Mark Lacey wrote:
> I have read through the TableGen Fundamentals documentation and been
browsing various .td files. One thing that is not clear to me is where things
like $src1 (as in GR32:$src1) are defined, and what they mean. The TableGen
Fundamentals page seems silent on this, and I have not found other documentation
that explains it. Browsing through the .td files has not helped, either
(although that has been quite useful to clarify things that are not spelled out
in detail on the TableGen Fundamentals page).
It's not entirely clear what you're referring to, but in general, those
are just arbitrary operand names.  They are defined and used within the
instruction patterns.  If that doesn't help, perhaps you could post a
specific example that you're having trouble with.

I've also been curious about this and couldn't find any documentation.
By
looking at the other TD files I can tell basically what it does but, It
would be nice to have documentation saying that *$var* is a variable and
what can and can not be done with it.
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On Mon, Aug 16, 2010 at 7:42 PM, Bob Wilson <bob.wilson at apple.com>
wrote:
>
> On Aug 16, 2010, at 7:24 PM, Mark Lacey wrote:
>
> > I have read through the TableGen Fundamentals documentation and been
> browsing various .td files. One thing that is not clear to me is where
> things like $src1 (as in GR32:$src1) are defined, and what they mean. The
> TableGen Fundamentals page seems silent on this, and I have not found other
> documentation that explains it. Browsing through the .td files has not
> helped, either (although that has been quite useful to clarify things that
> are not spelled out in detail on the TableGen Fundamentals page).
>
> It's not entirely clear what you're referring to, but in general,
those are
> just arbitrary operand names.  They are defined and used within the
> instruction patterns.  If that doesn't help, perhaps you could post a
> specific example that you're having trouble with.

I think I might have answered my own question with a little more browsing
and your mention of "arbitrary operand names". It appears that the
syntax
here is recordkind:$name where 'recordkind' has been previously defined,
and
'name' is just a descriptive name attached to a particular dag node
input,
which may (or may not) be referred to later in the definition of the current
record.

Is that correct?

Mark
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