On Mon, 4 Mar 2013 15:00:30 +0100 (CET)
Daniël Mantione <daniel.manti...@freepascal.org> wrote:
>
>
> Op Mon, 4 Mar 2013, schreef Mattias Gaertner:
>
> > On Mon, 4 Mar 2013 14:37:40 +0100 (CET)
> > Daniël Mantione <daniel.manti...@freepascal.org> wrote:
> >
> >>
> >>
> >> Op Mon, 4 Mar 2013, schreef Mattias Gaertner:
> >>
> >>> Can this be cached?
> >>> Maybe the compiler can reuse some results?
> >>
> >> No. The symtable lookups can be parsed, but the candidate selection, which
> >> I believe is actually more compute intensive, is dependend on the actual
> >> situation where the operator is called, for example the types of the left
> >> and right part, which would not yield very high hit rates.
> >
> > Why not?
> > I guess that a high percentage are only a few type,operator,type
> > combinations.
>
> interface
>
> function substring(x,y:unicodestring):cardinal;
> function substring(x,y:ansistring):cardinal;
> function substring(x,y:shortstring):cardinal;
>
> implementation
>
> {...}
>
> var a:unicodestring;
> b,c:ansistring;;
>
> begin
> a:='banana-split';
> b:='banana-split';
> c:='banana';
> writeln(substring('banana','banana-split'));
> writeln(substring(b,a));
> writeln(substring(a,a));
> end.
>
>
> ... we would have 3 cache lookups, and 3 misses. Then we have end of
> scope, the symtablestack changes, and we therefore have to invalidate the
> cache. In this example, a cache would therefore slowdown instead of
> speed-up.
Yes, that's one of the reasons why I disabled the cache in codetools for
procedure overloads.
But I was talking about operator overloads. AFAIK there far less
operator overloads. And if a unit uses operator
overloads, then usually only a few, but many times.
I guess many units do not use overloaded operators at all.
Is it possible to measure how much time the compiler spends on
searching overloaded operators?
Mattias
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