[LLVMdev] How to handle nested procedures?

[Patrick Meredith]

----- Original Message ----- 
From: "Jeff Cohen" <jeffc at jolt-lang.org>
To: <LLVMdev at cs.uiuc.edu>
Sent: Saturday, August 21, 2004 7:35 PM
Subject: [LLVMdev] How to handle nested procedures?


> How would following Pascal code be translated to LLVM?
>
>   procedure outer(a: integer): integer;
>     procedure inner(b: integer): integer;
>     begin
>       return a + b
>     end;
>   begin
>     return inner(a)
>   end;
>
> If outer(10) is called, it returns 20.
>
> The problem here is that inner has access to the locals and formal
> arguments of outer.  I do not see any direct support for this.  It could
> be handled by creating a struct for outer that contains everything used
> by inner procedures and explicitly passing its address to the inner
> procedures as an extra parameter.

There is no need for support of this, keep in mind that normal Pascal
compilers translate to local assembly code which also does not support inner
functions.  The struct idea is probably a good LLVM way to do it.  In a
normal compiler you would use displays or access links, which basically
consist of having some way to refer to the stack frame of a parent function.
The struct would be acheiving the same thing.

> Am I missing something?  If not, are there any plans to directly support
> this?
>
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