Re: Ada Generic Overhead Inquiry

[choinier@MITRE.ARPA (CPT Jacques C. Choiniere)]

In reply to Joe Rubel, on run-time overhead associated with Ada Generics:

  Tim Porter of SAIC ((porter@nosc-tecr)) did some work for us that explored
this issue.  His team developed an automatic code generator that, among other
things, uses Ada generics.  This work was done for WWMCCS Information System,
and is public domain software that will be sent to the Ada Repository on Simtel
20 in the next several months.  A formal report on this work is in the 
Proceedings of the Joint Ada Conference, 5th National Conference & Washington
Ada Symposium pages 334 to 343.
  In sum, he found that speed of the applications code was not noticeably 
different from "regular" code when running the compiled code.  Compilation
speed was fairly slow with the large system his team worked with (see report).
The PROBLEM he found was the size of the Ada code modules created by the 
automatic code generator and the generics it used.  The compiled code was
big.  He told me that this was a function of current VAX Compiler technology
and NOT a function of the Ada language.  The Compiler did not share any code
at all, even when the modules were identical.  THIS PROBLEM WAS SOLVED BY
TIM.  With careful selections of implementation alternatives (see report or
send him a note) he was able to shrink the generated code size and (I forgot
to mention this problem) handle the problem of in-line expansions of generics.
BY ALL MEANS READ THE REPORT OR TALK TO TIM TO GET THE DETAILS.  

CPT CHOINIERE, USA
WIS JPMO/XPT
jcc@mitre