Re: -gnatN breakage was: Child vs nested package : efficiency matter

[Vadim Godunko <vgodunko@gmail.com>]

On Jun 2, 8:45 pm, Georg Bauhaus <rm.dash-bauh...@futureapps.de>
wrote:
> On 02.06.10 16:39, Vadim Godunko wrote:
>
> > -gnatN is obsolete, you must use pragma Inline/Inline_Always with -
> > gnatn instead.
>
> Does this mean that 3rd party source cannot be
> inlined across units unless GNAT specific pragma Inline_Always
> is added to these 3rd party sources?
No. Use of -gnatn and -O is sufficient to enable inlining of
subprograms marked by pragma Inline. But not all subprograms will be
inlined but only definitely simple.

For example:

package P is
   function Simple (X, Y : Integer) return Integer;
   pragma Inline (Simple);
   function Complex (X, Y : Integer) return Integer;
   pragma Inline (Complex);
end P;

package body P is
   function Simple (X, Y : Integer) return Integer is
   begin
      return X + Y + 1;
   end Simple;
   function Complex (X, Y : Integer) return Integer is
   begin
      return X + Y + 1;
   exception
      when others =>
         return 0;
   end Complex;
end P;

with P;
function Test_Simple (X, Y : Integer) return Integer is
begin
   return P.Simple (X, Y);
end Test_Simple;

with P;
function Test_Complex (X, Y : Integer) return Integer is
begin
   return P.Complex (X, Y);
end Test_Complex;

$ gcc -c -S -O -gnatn test_simple.adb
$ gcc -c -S -O -gnatn test_complex.adb

From test_simple.s:

_ada_test_simple:
        leal    1(%rdi,%rsi), %eax
        ret

From test_complex.s:

_ada_test_complex:
        subq    $8, %rsp
        call    p__complex
        addq    $8, %rsp
        ret