Hi Brian,
Can you submit a bug report to http://bugzilla.xamarin.com? This is
something the JIT guys will have to take a look at because I don't know
enough to answer this question.
Thanks,
Jeff
On Fri, Sep 9, 2011 at 10:41 AM, Brian Schuth <br...@alphce.com> wrote:
> I have simplified this even further; with all the interface cruft out
> of the way, it seems like the problem is that even the simplest "join"
> is going to cause a JIT error? This sounds like a bug to me, but I'm
> happy to be told it's my fault :).
>
> The code that causes the problem is below, reduced to about its bare
> minimum. git://github.com/bschuth/MT-JIT-Problem.git has been updated
> as well...
>
> But the problem is really simple: I have two collections of objects
> (sessions and scores) connected by an integer key in a one-to-many
> relationship, where score.OwnerID equal session.SessionID. This linq
> fails:
>
> from s in sessions
> join score in scores
> on s.SessionID equals score.OwnerID
> select score.Name;
>
> Are joins just not possible here? What to do? Thanks.
>
> ==== Source: PROBLEMLINQ.CS STARTS
> using System;
> using System.Linq;
> using System.Collections.Generic;
>
> namespace JIT20110908
> {
> public class ProblemLinq
> {
> public IList<string> Execute ()
> {
> List<ActualScore> scores = new List<ActualScore> ();
> ActualScore score1 = new ActualScore () {
> Name = "ACTIVITIES",
> OwnerID = 666
> };
> scores.Add (score1);
>
> List<MySession> sessions = new List<MySession> ();
> MySession mysession = new MySession () {
> SessionID = 666,
> };
> sessions.Add (mysession);
>
> var summaryVar = from s in sessions
> join score in scores
> on s.SessionID equals score.OwnerID
> select score.Name;
>
> List<string> summaryRows = summaryVar.ToList();
> return summaryRows;
> }
> }
>
> public class MySession
> {
> public int SessionID { get; set; }
> }
>
> public class ActualScore
> {
> public int OwnerID { get; set; }
> public string Name { get; set; }
> }
> }
>
> On Fri, Sep 9, 2011 at 9:07 AM, Brian Schuth <br...@alphce.com> wrote:
> >
> > Thanks, this confirms my vague sense that the problem came from something
> the LINQ depends on that is not generated during compilation. This specific
> fix doesn't work, since the type involved isn't quite the same. I'm
> relatively new to the guts of LINQ, so I think I need some help parsing
> exactly what the error is.
> > The stack trace says it is attempting to compile this method:
> > System.Linq.Enumerable:<ToLookup`2>m__18<JIT20110908.ActualScore,
> int>(JIT20110908.ActualScore)
> > I tried just substituting ActualScore as the type in your fix, but that
> doesn't seem to do it either.
> > The exception occurs inside the method:
> > at System.Linq.Enumerable.ToLookup[ActualScore,Int32,ActualScore]
> (IEnumerable`1 source, System.Func`2 keySelector, System.Func`2
> elementSelector, IEqualityComparer`1 comparer) [0x00079] in
> /Developer/MonoTouch/Source/mono/mcs/class/System.Core/System.Linq/Enumerable.cs:2915
> > I've read the docs on Enumerable.ToLookup, and maybe I just need more
> coffee, but I'm not quite getting what this may be trying to do at the
> mysterious line 2915 that is causing a crash...
> > Can anyone point me just a little closer? I'm just trying random stuff at
> the moment to see if I magically create the thing that MT wants.
> > If there's a resource out there that explains the guts of LINQ well
> enough to start figuring out what's going on under the hood here, I'd love
> to know about it!
> > Thanks,
> > bjs
> > On Fri, Sep 9, 2011 at 3:15 AM, Pete Macko <pma...@me.com> wrote:
> >>
> >> Try putting this in your code and calling it from FinishedLaunching
> >> private void MonoTouchForcedCompilationHacks()
> >> {
> >> {
> >> var hack1 = new IFooSession[0];
> >> if(!((ICollection< IFooSession>)hack1).Contains(// some bogus lambda or
> other thing to force the system to evaluate the collection))
> >> {
> >> blah blah blah log some crap here or whatever
> >> }
> >> }
> >> }
> >> Could put this anywhere I guess, but I got tired of dealing with jit
> errors and stuck all this sort of stuff in one place for the sake of
> organization.
> >> Then again, it could be your sample values in the code that are making
> baby jeebus cry -- and MT is watching! :)
> >> -pm
> >> On Sep 8, 2011, at 4:22 PM, Brian Schuth wrote:
> >>
> >> A couple of months back I hit JIT errors when using LINQ for objects. I
> was never able to resolve them, but as the LINQ involved was pretty simple,
> I just "unrolled" it into procedural code.
> >> Now I'm getting more of them, and I'd really prefer to leave the LINQ
> alone if possible. The exception I'm getting today is:
> >> Attempting to JIT compile method
> 'System.Linq.Enumerable:<ToLookup`2>m__18<JIT20110908.ActualScore, int>
> (JIT20110908.ActualScore)' while running with --aot-only.
> >> Below is my ProblemLinq.cs file, which contains a class with an
> Execute() method that causes this error. I realize there's a lot of
> interfaces and classes here; this is a severely dumbed-down version of the
> actual code, which is part of a cross-platform reporting library. The code
> in question is running in Windows as part of a production product.
> >> I've read the "Limitations" section on the xamarin website, and while I
> can't say I understand it totally, I don't see that my code is doing any of
> the verboten virtualization things; although LINQ does enough magic that I
> don't necessarily know the secondary effects of the code.
> >> The stack trace from the error this class causes follows the code.
> >> I'm running MT 4.0.7 and MD2.6.
> >> Am I doing some LINQ thing I shouldn't? Or is MT missing something?
> >> Thanks.
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