[LLVMdev] Seemingly ambiguous parameter lists
robert at mykland.com
Tue Aug 26 20:32:01 PDT 2003
I had a second question which is probably a dumb question, but here
goes. I'm just wondering how a function that has all varargs knows what to
do. I'm only familiar with the C style of varargs. In that case you
generally used one or more fixed parameters that told you how to interpret
the rest. Like the format string in printf, for example. I suppose the
function could look at a static variable somewhere to get this data. That
sounds messy. Are these functions member functions with an implied first
parameter perhaps? If so, why not explicitly?
At 04:17 PM 8/26/2003 -0500, Chris Lattner wrote:
>On Tue, 26 Aug 2003, Robert Mykland wrote:
> > And while we're on the subject to the type definitions table, what's the
> > difference between
> > 0e 07 01 00
> > function returning Int ( Void )? Function returning Int ( ... )?
>Void is not a legal argument. The bytecode file uses the void marker as
>a way to store the ... for a varargs function. IE, the declaration:
>in C, becomes the LLVM type 'void ()*' %foo. The C declaration:
>becomes the LLVM type 'void (...)*' %foo, which is stored in the bytecode
>file (to be compact) as 'void (void)*'.
> > 0e 07 00
> > Function returning Int ()
>That is just 'int ()', function returning int, with no arguments.
> > I'm guessing the former really is a function returning Int ( ... ), but how
> > is the callee supposed to decode the parameter list? I'm an old callee and
> > I don't know this new trick. :-)
>Void is not a legal argument type, it is just used as a marker in the
>bytecode files. :)
Robert Mykland Voice: (831) 462-6725
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