Re: GNAT internals question

["David C. Hoos" <david.c.hoos.sr@ada95.com>]

Hi,

I don't believe ada_main___elabb will ever be called because the
basic structure of the Ada_Main packages is constrolled by the binder,
and the generated code (purposely, I believe) doesn't need any
elaboration code.  If there were any elaboration code generated, it
would need to be called _before_ adainit, given the rule that elaboration
of a package must be done before any of the package's subprograms
is called.

The elaboration code for all programmer-generated code is called by
adainit, so anything that the programmer can do to affect what is in the
Ada_Main package is confined to the elaboration procedures called by
adainit.

The only initialization of data items in the Ada_Main package is done
by means of literals -- i.e., no subprogram is called to do any of the
initialization -- hence, the initialization is accomplished by the
generation
of an initialized data section within the object file.

Am I making this clear?

----- Original Message -----
From: "sk" <noname@myob.com>
To: <comp.lang.ada@ada.eu.org>
Sent: Wednesday, June 26, 2002 4:15 PM
Subject: Re: GNAT internals question


> Hi,
>
> "David C. Hoos, Sr." <david.c.hoos.sr@ada95.com>
> > ... not a single instance of ada_main___elabs.
>
> Sorry, I mis-remembered, it is "ada_main___elabb"
> I am refering to.
>
> So far my experience is also that it is not called
> but that doesn't mean that it never is used.
>
> It is difficult for me to describe what I am asking,
> but ...
>
> procedure Nothing is
> begin
>     null;
> end Nothing;
>
> The pragmas are to remove all external references
> and dependencies on the GNAT runtime.
>
> Linux shell commands :
>
>     gnatmake -c -v nothing
>     gnatbind -v nothing
>     gcc -v -c -S b~nothing.adb
>
> producing "b~nothing.s" which contains the elusive
> "ada_main___elabb" (AMEB an acceptable acronym ?).
>
> The GNAT Ada main function has a structure of
>
>     adainit
>     call nothing
>     adafinal
>
> I believe that when circumstances require, AMEB will
> both contain useful code and be called as part of the
> final binary.
>
> Isolating where it is called from is my goal. Prior to
> "adainit", from "adainit" or between "adainit" and the
> nothing call etc.
>
> AMEB might be a permanent and "legacy" stub, but I doubt
> it. I suspect that some features of Ada and GNAT will
> populate this function with useful code and call it when
> necessary.
>
> Trying to discover the circumstances.
>
> Thanks :-)
>
> --
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