Re: How do I disable elaboration code on this

[Georg Bauhaus <rm-host.bauhaus@maps.futureapps.de>]

On 4/10/11 7:20 PM, Lucretia wrote:
>> I think what you need here is
>>
>> Vector : constant Vectors;
>> pragma Import (Ada, Vector);
>> for Vector'Address use Addr;
>>
>> since you don't want Vector to be initialized.
>>
>> Vector will not be initialized because you have pragma Import for it.
>
> Nope, this didn't work. Checked the RM. Seems that if I use pragma
> Import (Ada, Vector) then the compiler assumes that this is an
> external (possibly in ASM) that is already initialised and therefore
> cannot be initialized to my ISR subprograms.

Don't know whether the following just silences the compiler
or whether it solves the elaboration code issue. (The issue
seems to appear with variables that have an address clause
specified.  There code below seems to result in two _init
procedures, one for CbW and one for Vectors; the assembly listing
shows a number of moves related to Vectors).

The idea was to replace Cb with a limited record CbW
that has a Cb component. The component is default initialized
to point to Dummy.

pragma Restrictions (No_Elaboration_Code);

with System;

package ISR is
    procedure Dummy;
    pragma Convention (C, Dummy);

private
    type Cb is not null access procedure;
    pragma Convention (C, Cb);

    type CbW is limited record
       C : Cb := Dummy'Access;
    end record;
    type Vectors is array (1 .. 4) of CbW;
    pragma Convention (C, Vectors);

    Addr : constant System.Address := System'To_Address
         (16#0000_0000#);

    Vector : Vectors;
    pragma Import (Ada, Vector);
    for Vector'Address use Addr;
end ISR;
package body ISR is
    procedure Dummy is
    begin
       null;
    end Dummy;
end ISR;