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From: =?utf-8?Q?Yannick_Duch=C3=AAne_=28Hibou57?=
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 <yannick_duchene@yahoo.fr>
Newsgroups: comp.lang.ada
Subject: Re: Efficiency of code generated by Ada compilers
Date: Wed, 11 Aug 2010 01:28:25 +0200
Organization: Ada At Home
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Date: 2010-08-11T01:28:25+02:00
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Le Wed, 11 Aug 2010 00:50:40 +0200, <anon@att.net> a =C3=A9crit:
> While the main expression are equal. The code generation by Ada compil=
ers
> versus C or C++ is less efficient do to a number of factors.
>
>   1. Elaboration:     Ada compilers can generate run-time elaboration
>                       routines that must be executed before starting
>                       the main users program. C/C++ compilers do not
>                       perform any run-time elaboration, which cause
>                       the execution and code generation to be more
>                       efficient but cause the less program to be less
>                       reliable.
>
>   2. Run-Time Checks: The Ada compiler generates inline run-time check=
s
>                       which the C/C++ compiler do not.  Using the prag=
ma
>                       "suppress" statement can eliminate most checks. =
The
>                       absent of these checks makes C/C++ less reliable=
.

Yes. You have the choice (with the former)

>             pragma Suppress ( All_Checks, ON =3D> <name 1>,
>                                                ...
>                                            ON =3D> <name n> ) ;
>              --  removes all checks on that set of names only.
>              --  Names may be an object such as an array or routine
>              --  Also, the "ON =3D>" symbols are optional

Interesting point. Is that GNAT or other compiler specific ? I do not th=
is  =

variant in the reference.

In =E2=80=9C11.5 Suppressing Checks=E2=80=9D:
> 3/2    The forms of checking pragmas are of a pragma Suppress is as  =

> follows:4/2    pragma Suppress(identifier [, [On =3D>] name]);
> 4.1/2  pragma Unsuppress(identifier);

Standard or not, this seems nice. This may be better for centralized  =

management of runtime-checks.

-- =

There is even better than a pragma Assert: a SPARK --# check.
--# check C and WhoKnowWhat and YouKnowWho;
--# assert Ada;
--  i.e. forget about previous premises which leads to conclusion
--  and start with new conclusion as premise.