Re: C's trikery semantic opens up backdoor in new Linux kernel

[Erlo Haugen <_elh_@_terma_._com_>]

On Fri, 14 Nov 2003 10:04:02 +1300
Craig Carey <research@ijs.co.nz> wrote:

> On Wed, 12 Nov 2003 15:09:52 +0100, Vinzent 'Gadget' Hoefler wrote:
> ...
> >Duncan Sands wrote:
> ...
> >>> constant value you should always state the constant first:
> >>> |if ((__WCLONE|__WALL) == options) && (0 = current->uid))
> >>>
> >>> wouldn't compile, either.
> 
> ...
> >No. And you? Do you really think that the linux kernel community would
> >like the idea of using a *function* to get/set a plain simple integer
> >variable? I already hear them scream: "It would be too inefficient.
> >Especially in a *kernel*!" ;-)
> 
> Ada 95 could be enhanced so that specified record fields could be
> read-only. Some one could perhaps produce data showing that it is needed
> or else it may not appear.
> 
> De-referenced pointers can identify read-only data
>   "type Ptr is access constant X;".
> Then Ada 95 lacks a limited pointer type, and also a pointer that can
> be assigned but which lacks a "=" equality operator.
> 
> 
> 
> 

Isn't this a matter of optmization? If all the function does is assigning a
value, then the compiler could convert it an inline assignment:

My_Variable : something;
function Get_A return something is
begin
  return My_Variable;
end Get_A;



then (possibly in another package)

.
.
.
This_Variable := Other_Package.Get_A;
.
.

could be optimized (in the object code)to

.
.
.
This_Variable := Other_Package.My_Variable;
.
.
.



Just a thought, I don't know much about compiler construction, but it seems to
me to be a way to go.

-- 
Erlo
Remove the underscores
Sorry, I don't have time for this. I've got bugs to write.