[Vm-dev] Cross file updates

[David T. Lewis]

On Thu, Mar 07, 2013 at 11:06:32PM -0500, David T. Lewis wrote:
>  
> On Thu, Mar 07, 2013 at 06:07:45PM -0800, tim Rowledge wrote:
> > 
> > The self var: #dispBits type: 'unsigned char * '. line seems to do nothing in the current VMMaker; I'm pretty sure it used to. Somewhere the SmartSyntax codegen stuff is over-riding that decl (or ignoring is more likely I guess) because of the primitive declaration using a 'WordArray'; that causes the use of (unsigned *). Using ByteArray makes is use (char *) instead.
> > 
> 
> It's certainly something related to that line. Nowadays, declarations of the form:
> 
> 	self var: #dispBits type: 'unsigned char * '.
> 
> are done instead with method annotations:
> 
> 	<var: #dispBits type: 'unsigned char * '>
> 
> but I have tried to keep the original mechanism intact in trunk VMMaker.
> 
> I tried changing the declaration to <var: #dispBits type: 'unsigned char * '>
> and I still get exactly the same incorrect code generation.
> 
> Tim, if you have an older version of VMMaker readily at hand from your
> recent Pi work, could you take a look at the generated code for HostWindowPlugin
> and see if it has this same bug?
> 
> Dave

Actually, looking that this again I have to say that the slang makes no
sense at all. We have:

	self var: #dispBits type: 'unsigned char * '.

which as you pointed out is a declaration that contradicts the WordArray
declaration in the parameter list:

	self primitive: 'primitiveShowHostWindowRect'
		parameters: #(SmallInteger WordArray SmallInteger SmallInteger SmallInteger
				SmallInteger SmallInteger SmallInteger SmallInteger).

My guess is that the SmartSyntax generator declares the parameter #dispBits
improperly, and somebody noticed that problem and tried to fix it by adding
the self var: #dispBits type: 'unsigned char * ', which does not the fix the
problem at all. In fact it has no effect on the generated code, but it looks
like it *should* be doing something, thus contributing to the general confusion.

I dug up and older version of HostWindowPlugin from the Squeak 3.8 time frame,
and the self var: #dispBits type: 'unsigned char * ' is not present in that
version.

Bottom line: The "self var: #dispBits type: 'unsigned char * ' " is probably
a mistake that should be removed, and there is also a bug(let) in the SmartSyntax
code generator that should be fixed.

And I hate to say it but you were probably right to change the header declaration
to (unsigned *) in the first place, so maybe your last reversion should be reverted.
Better to get the declarations right in Cross and fix up VMM and elsewhere as needed.

Dave