Re: objc-lang.c portability (Was Re: [PATCH] Step over Objective-C dispatch function)

Andrew Cagney
2003-03-27T15:53:57Z

>
> On Thursday, March 20, 2003, at 02:08 PM, Andrew Cagney wrote:
>
> I've looked at what the underlying code is trying to do and, unfortunatly, the original objc-lang.c botched its portability(1), sigh! The file is currently native only so infrun.c can't directly refer to objc-lang.c, and hence, will need to go via a dispatch table. Going via a dispatch table wouldn't hurt anyway.
>
> (1) I noticed that the parameter extract methods assume host=target.
>
>
> I'm wondering what's not portable with objc-lang.c? With the remaining patches I have that require this, I was thinking it might be easier to just fix it now. The alternative appears to be adding a whole bunch of things to the language_defn structure. I admit I don't really understand the problem though.

Both getting objc-lang.c portable and extending the language vector are
things that will, one day, need to be done :-/ My guess is that it will
be quicker, and lower risk, to attack the language vector side of the
problem then to more slowly audit / fix the portability problems. This
will at least make it possible to enable objc for one or two key native
systems (e.g., i386 GNU/Linux).

Language vector additions are largly a case of changing this:

switch (current_language)
case C: do something C like;
case C++: do something C++ like;
...

into something like:

switch (current_language)
...
default:
current_language->do something language like;

which is very mechanical. There is plenty of prior art so approval is
pretty mechanical. Contrast it to the problem DanielJ pointed out (and
I hinted at):

> At the very least FETCH_ARGUMENT and CONVERT_FUNCPTR need to go into
> the architecture vector.

As they stand, these new methods won't go into the architecture vector.
Adding a new architecture method requires care and consideration, and
for the above, they will definitly need change.

Andrew