Re: Can't set executable stack size during compilation

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

On 1/5/12 5:35 AM, Bill Findlay wrote:

> As it happens, when I ran it I got:
>
>> /Users/wf/KDF9/emulation/Build: ./onstack
>>
>> raised CONSTRAINT_ERROR : onstack.adb:19 range check failed
>
> because my default GNAT switches ask it to (attempt to) check for uses of
> uninitialized variables.

A possible solution of GNAT's stack size issue, an Ada solutions of sorts,
appears to be available with tasking. Move the computation to a task
and add

    pragma Storage_Size (Minimum_Storage_Size);

in the task's declaration, thus

procedure Run_in_Task is

    type Num is range 1 .. 10000;
    type Index is range 1 .. 512;
    type Table is array (Index, Index) of Num;

    type Big is record
       X1, X2, X3, X4, X5: Table :=
         (others => (others => Num'First));
    end record;

    Minimum_Storage_Size : constant := 11_000_000;
    --  task's storage size; addressing stack size issues with GNAT
    --  about equal to 512 * 512 * 2 * 5 * 4

    task Onstack is
       pragma Storage_Size (Minimum_Storage_Size);
    end Onstack;

    task body Onstack is separate;

begin
    null;
end Run_in_Task;

separate (Run_in_Task)
task body OnStack is

    function Add (A, B : Big) return Big is
       Result : Big;

       function Add_Component (Left, Right: Table) return Table is
          Result : Table;
       begin
          for M in Left'Range loop
             for N in Right'Range loop
                Result (M, N) := Left(M, N) + Right(M, N);
             end loop;
          end loop;
          return Result;
       end Add_Component;

    begin
       Result.X1 := Add_Component (A.X1, B.X1);
       Result.X2 := Add_Component (A.X2, B.X2);
       Result.X3 := Add_Component (A.X3, B.X3);
       Result.X4 := Add_Component (A.X4, B.X4);
       Result.X5 := Add_Component (A.X5, B.X5);
       return Result;
    end Add;

    X, Y: Big;
    Data : Big;
begin
    Data := Add (X, Y);
    pragma Inspection_Point (Data);
end OnStack;