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List:       gdb
Subject:    Re: objc-lang.c portability (Was Re: [PATCH] Step over Objective-C dispatch function)
From:       Andrew Cagney <ac131313 () redhat ! com>
Date:       2003-03-27 15:53:55
Message-ID: 3E831E93.6010803 () redhat ! com
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> 
> 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


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