Re: Crosspost: Help wanted from comp.compilers

[Hyman Rosen <hyrosen@mail.com>]

John R. Strohm wrote:
 > your recollection might be faulty

Here's some evidence. I have no idea about its quality.
Given the unfortunate lack of a worldwide web in the 80s,
it's not clear where to search for more data. Looking at
some of the links below, I think a big problem was that
many of the systems forced all dependents of a file to be
recompiled when the file was recompiled, regardless of
whether the source had changed. I believe this was one
reason that GNAT decided to go with a source-based model
for its library.

<http://www.ics.uci.edu/~softtest/adamakegen.html>
     "In our development of large Ada systems, we have found
      several problems with use the partial recompilation tool
      supplied by Verdix/SunAda. They are:

         * The dependencies are often incorrect,
           leading to corruption of the Ada libraries.
         * It does not support libraries that form a loop."

<http://www.seas.gwu.edu/~adagroup/sigada-website/barnes-html/chap1.html>
     "A common consequence of the flat structure was that packages
      become large and monolithic. This hindered understanding and
      increased the cost of recompilation."

<http://archive.adaic.com/docs/flyers/95fast.html>
     "Say good-bye to the days of multiple-day recompilation of
      Ada 83 software."

<http://compilers.iecc.com/comparch/article/93-09-039>
     "Compiling one of the earlier units again, perhaps because of a
      change to the source, or a desire to change the optimisation level
      or amount of debugging support, causes this method of implementing
      the check to fail. In order to link the application, all the
      'obsolete' compilation units are going to have to be recompiled.
      This step may take a considerable amount of elapsed time - minutes,
      hours, even days in large applications."

<http://ftp1.support.compaq.com/public/Readmes/vms/adavaxeco13030.README>
     " o  Smart recompilation allocates an object the wrong PSECT
          resulting in an ACCVIO at run-time, or non-zero values in the
          ZERO PSECT.

       o  Smart recompilation associated compiler ACCVIO when processing
          use clauses.

       o  Smart recompilation associated compiler ACCVIO in SS_BASE_TYPE
          during hint processing."

<http://sage.inel.gov/uman_sagestmeridianport.htm>
     "In order to debug any package both the spec and body must be
      recompiled with the fD flag. Recompiling the spec then causes
      any packages 'with'ing this one to be recompiled. Depending
      on the need this can cause a massive recompilation."