Poly/ML February 2009

polyml@lists.polyml.org

4 participants
3 discussions

Segmentation fault when saving state
by pclayton＠taz.qinetiq.com 03 Apr '09

03 Apr '09

David, We have noticed some interesting behaviour with the state saving in Poly/ML 5.2/5.2.1--- possibly a sign that something isn't quite as intended. If poly is started and the command PolyML.SaveState.saveState "test"; is repeatedly entered, a segmentation fault eventually occurs. On my machine it always happens after 22 times. With the debug level set to 2 or 3, we get: Bad pointer 0x0d479050 found Aborted If we enter PolyML.fullGC (); just before the 22nd go, there is no segmentation fault. However, continuing to enter the original save state command results in the exception Exception- SysErr ("Out of Memory", SOME ENOMEM) raised after 8 more goes. We found this example more by chance. We have had a few other repeatable segmentation faults when saving the state but on very large examples and these are hard to reduce down. (They may be related to the above issue.) In each case, the segmentation fault could be avoided by executing PolyML.fullGC first. Generally, if we cannot create an SML script that generates an error, what is the best way to track down an issue? Thanks, Phil The information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). The information in this communication may be confidential and/or legally privileged. Nothing in this e-mail is intended to conclude a contract on behalf of QinetiQ or make QinetiQ subject to any other legally binding commitments, unless the e-mail contains an express statement to the contrary or incorporates a formal Purchase Order. For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful. Emails and other electronic communication with QinetiQ may be monitored and recorded for business purposes including security, audit and archival purposes. Any response to this email indicates consent to this. Telephone calls to QinetiQ may be monitored or recorded for quality control, security and other business purposes. QinetiQ Limited Registered in England & Wales: Company Number:3796233 Registered office: 85 Buckingham Gate, London SW1E 6PD, United Kingdom Trading address: Cody Technology Park, Cody Building, Ively Road, Farnborough, Hampshire, GU14 0LX, United Kingdom http://www.qinetiq.com/home/notices/legal.html

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Installing Poly/ML
by rda＠lemma-one.com 02 Mar '09

02 Mar '09

I have just learnt a few things installing Poly/ML on a Ubuntu 8.04 system freshly built from the Desktop CD: 1) Ubuntu comes out of the CD with 3/4 of a C compiler. You get gcc, but not libc, so you can compile hello-world.c but not link or run it. The configure script notices this. Installing the package libc6-dev fixes it. 2) But, the configure script doesn't seem to check that there is a C++ compiler (perhaps it should???). The output from configure looked OK, but make fell over with an error: ../libtool: line 1281: g++: command not found Installing the package g++ fixes this. 3) But, poly builds and installs but won't run, because Ubuntu is one of those systems that doesn't include /usr/local/lib on the library path, After starting again with "./configure --prefix=/usr", I have a working compiler. Regards, Rob.

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ML compiler
by ldixon＠inf.ed.ac.uk 06 Feb '09

06 Feb '09

Hi PolyML people, I'm interested in trying to shrink the size of my binary/heap file; I have 18604 lines of library code; the first 6922 lines give a 2.6 MB heap; the next 1200 lines on top of this give a 15 MB heap. I then have 7500 lines of program that push the heap up to 138 MB. (on some Linux' this becomes over 200MB!) I'm doing garbage collection before writing the heap (although it sounds like this is now done automatically); and I can't quite tell how I'm getting this rather nasty blow up in heap size. I suspect my use of substructures, I often have things like: signature N1 ... signature N2 = sig structure n1 : N1 ... end functor N2Fun(n1 : N1 and ...) : N2 = struct structure n1 = n1; ... end; structure n1 : N1 = ... structure n2a = functor(n1 : N1 and ...) : N2; structure n2b = functor(n1 : N1 and ...) : N2; is the code for the substructure n1 literally getting copied each time? Even with this I find it hard to imagine how I'd generate 120 MB of machine code from 7500 lines of ML... I noticed some forget functions in the PolyML compiler; is there some clever way to say all I care about is stuff reachable from calling some specified function? suggestions very welcome, best, lucas

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Poly/ML February 2009