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Newsgroups: comp.lang.ada
Date: Tue, 17 Oct 2017 22:56:28 -0700 (PDT)
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Subject: Re: Why does Ada compile slower than Python?
From: olivermkellogg@gmail.com
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Xref: news.eternal-september.org comp.lang.ada:48498
Date: 2017-10-17T22:56:28-07:00
List-Id: <comp.lang.ada>

On Tuesday, October 3, 2017 at 11:08:59 PM UTC+2, Victor Porton wrote:
> Victor Porton wrote:
> [...]
> According this test (valid only for very short programs) compiling Ada is=
=20
> slower only two times.
>=20
> Maybe I was under a wrong impression, because I got this impression when =
I=20
> compiled tens of Ada files in a row and my brain was focused on total=20
> compilation time rather than compilation time for one file?
>=20
> Is GNAT really much slower than Python? or was it a false impression?

When compiling many interdependent packages GNAT is definitely slower than =
it could be. This has to do with the fact that GCC/GNAT can only handle one=
 file at a time. E.g. if you provide 100 files on a single gcc command line=
 then gcc loads and compiles each file separately as though you were provid=
ing 100 commands with one file per command.
Some years ago I had started an experiment to add AST (abstract syntax tree=
) caching to GNAT and had gotten as far as the Ada frontend (GNAT trees); h=
owever, the major effort for making this work is in the later stages of the=
 compiler (GNU trees, etc).

Oliver