From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,d6f7b92fd11ab291 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-07-17 05:26:02 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!newshub.sdsu.edu!elnk-nf2-pas!newsfeed.earthlink.net!stamper.news.pas.earthlink.net!stamper.news.atl.earthlink.net!harp.news.atl.earthlink.net!not-for-mail From: Marin David Condic Newsgroups: comp.lang.ada Subject: Re: Crosspost: Help wanted from comp.compilers Date: Thu, 17 Jul 2003 08:25:59 -0400 Organization: MindSpring Enterprises Message-ID: <3F1695D7.8010306@noplace.com> References: <1058275843.720814@master.nyc.kbcfp.com> <3F158832.1040206@attbi.com> <1058378673.35463@master.nyc.kbcfp.com> <1058390613.119827@master.nyc.kbcfp.com> <3F15DE74.3030303@noplace.com> NNTP-Posting-Host: d1.56.b8.a8 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Server-Date: 17 Jul 2003 12:26:02 GMT User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 (OEM-HPQ-PRS1C03) X-Accept-Language: en-us, en Xref: archiver1.google.com comp.lang.ada:40399 Date: 2003-07-17T12:26:02+00:00 List-Id: Not always the compiler maker either. I know that the DEC compilers had a "feature" wherein they could compile a file on two different occasions and get different code, despite there being no change in the file. The reason was that the optimizer took advantage of the available working set to bring in more code for optimization. Depending on the demand for memory, it might get more or less memory on two different passes and hence could (and did on at least three occasions I witnessed) produce different code for an unchanged file. It was rare, but it was a risk. For most people, this wouldn't be a problem, but for safety critical embedded systems, it was. Maybe this example doesn't really apply to specifications, since there may not be much/any code generation going on and little/no optimization - but it illustrates the difficulties the compiler writers may have in knowing the consequences of what may happen in the field. So, yes, I agree, compilers ought not to force recompilation when it is unnecessary. But sometimes it is difficult to know when "unnecessary" is a certainty & I can be forgiving of implementations that try to err on the side of caution. MDC Hyman Rosen wrote: > Marin David Condic wrote: > >> Can you really be certain that if you recompile a spec with different > > > compiler options, that this will in no way impact the way other things > > might rely on it? > > Me, no. The compiler maker, yes. > -- ====================================================================== Marin David Condic I work for: http://www.belcan.com/ My project is: http://www.jast.mil/ Send Replies To: m c o n d i c @ a c m . o r g "In general the art of government consists in taking as much money as possible from one class of citizens to give to the other." -- Voltaire ======================================================================