Re: [Pnet-developers] Array access in the java compiler ?

[Rhys Weatherley]

On Friday 28 March 2003 02:18 am, Gopal V wrote:

> Other than generating
>
> int [][]a=new int[10][];
> for(int i=0;i<a.length;i++)
> {
>       a[i]=new int[10];
> }
>
> I can't find any decent way to have the constructor.

That's pretty much what you have to do.  Either that or use a helper method to 
do the work for you.  e.g.

    Array CreateJavaMultiArray(Type type, params int[] dims);

This would use "Array.CreateInstance" within a recursive create loop to build 
up the array and return it.

> Similarly array accesses seem to degenerate into recursive ldelems when
> I do it this way.
>
> //a[0][0]=42;
>
> ldloc.1
> ldc.i4.0
> ldelem
> ldc.i4.0
> ldc.i4.s 42
> stelem.i4

That's how javac compiles it too.

> So do I need to fix up ILNode_JavaArrayAccess and ILNode_JavaNewExpression
> ?. (I hate that !)

You should be able to avoid "JavaArrayAccess".  The existing array access code 
will evaluate "a[0]" with ILNode_GenValue, and then call ILNode_Prepare for 
the next dimension.  It should just happen automatically.

You will probably need JavaNewExpression for multi-dimensional arrays though 
(single-dimensional should be OK).

Every front-end language will have a few language-specific node types (e.g. 
ILNode_CBitField in cscc/c/c_defs.tc).  This is to be expected.

Cheers,

Rhys.