Re: Profiling Ada binaries

[rieachus@comcast.net]

On Tuesday, July 26, 2016 at 4:37:31 AM UTC-4, Markus Schöpflin wrote:
 
> GNAT by default uses static elaboration. There should be no elaboration checks 
> when calling the generic versions. Or am I mistaken here?

From the GNAT documentation: Strict conformance to the Ada Reference Manual can be achieved by adding two compiler options for dynamic checks for access-before-elaboration on subprogram calls and generic instantiations (-gnatE) and stack overflow checking (-fstack-check).

>  > I believe GNAT
> > has non-generic versions for Short_Float, Float, and Long_Float which use
> > the hardware built-ins.  But I doubt you would get that automatically with
> > -O1.

> Even using the non-generic versions I have not been able to get the hardware 
> built-ins. The best I can achieve for a call to e.g. cos(X) is: 

>         call    ada__numerics__long_elementary_functions__cos

That's silly.  A project for a rainy afternoon.  Hmm.  May rain today...

Again GNAT docs to the rescue: 15.1 Machine code insertions:

The equivalent can be written for GNAT as:

    Asm ("fsinx %1 %0",
         My_Float'Asm_Output ("=f", result),
         My_Float'Asm_Input  ("f",  angle));

I assume I wrap that in a function call:

  function Sin(Angle: in Float) return Float is
    Asm ("fsinx %1 %0",
         My_Float'Asm_Output ("=f", result),
         My_Float'Asm_Input  ("f",  angle));
  end Sin;

Now all I have to do is put together a set of test cases...