EGCS: pointer to member functions.

[Alexandre Oliva]

On Jun 15, 1999, mrs@wrs.com (Mike Stump) wrote:

>> From: Alexandre Oliva <oliva@dcc.unicamp.br>
>> Date: 15 Jun 1999 03:54:56 -0300

>> On Jun 15, 1999, Brendan Simon <brendan@dgs.monash.edu.au> wrote:

>> > Why is there so much overhead in calling a function via a pointer as
>> > apposed to calling it directly?

>> Pointer-to-methods don't know whether they point to virtual methods or
>> not, so the caller must have code for both cases.  Methinks this could
>> be improved by generating thunks that perform dynamic binding in the
>> case of invoking virtual methods, but maybe I'm missing something.

> Try it, lay it out, read up on C++ and what is required of the
> generated code.  :-) I have, I think.  :-) Hint, there is no separate
> type for pointer to virtual method and pointer to non-virtual member.

Yup, no problem.  You can decide what to do when the pointer is
created.  If the method is non-virtual, you can just take its address
directly.  If not, you could take the address of an implicitly-defined
non-virtual method that works just like a thunk.  This non-virtual
method could be handled just like template functions, in terms of
implicit instantiation, so I don't see a problem here.  Is there any
flaw in my reasoning?

-- 
Alexandre Oliva http://www.dcc.unicamp.br/~oliva IC-Unicamp, Bra[sz]il
{oliva,Alexandre.Oliva}@dcc.unicamp.br  aoliva@{acm.org,computer.org}
oliva@{gnu.org,kaffe.org,{egcs,sourceware}.cygnus.com,samba.org}
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