[Mono-list] mono_verify_corlib - Checking on non-standard fields - Why?

[bvv]

Hi Piers,

In doing a mix & match of corlibs between CLRs I found that the 
issue involves more than the icalls!

Running mint I found that there's a check done on the corlib. 
interp.c has a call to funciton "mono_verify_corlib" which is 
found in verify.c.
I was surprised to find that the verification involves checking if 
certain "private" fields are present in various classes of corlib. 
I say "private" because these fields are *NOT* part of the ECMA 
standard class definitions.

I stepped through Rotor code to see if they do they same thing, 
and yes they do!

If u try to replace Rotor's corlib with mono's corlib the checking 
that Rotor does on the corlib fails because the *private* fields 
that Rotor expects to find are either not available in mono's 
corlib or the name of the field differs!

Now, what i don't understand is
What's the purpose of corlib verification?
Why is corlib verification done based on such *private* fields?

Thanks



On Tue, 31 Dec 2003 Piers Haken wrote :
>Yes, you're right: the corlib interfaces are standardized. 
>However the
>_internal_ interface between corlib and the runtime is not, and 
>this is
>where the incompatibility lies.
>
>Corlib needs to do stuff that cannot be written in c#, eg.
>creating/reflecting types, IO, threading, GC, etc... The 
>functions for
>doing these are native (C for mono, C++ for MS) functions 
>exported by
>the runtime. In mono they are referred to as 'icall's (see
>mono/mono/metadata/icall.c) and they are runtime-specific.
>
>I believe that the only Mono DLL that uses internal calls is 
>corlib.dll.
>However many of the Microsoft DLLs also use their own internal 
>calls
>exported from the MS runtime. This means that although, in theory 
>and
>for example, you can use Mono's System.XML.DLL on the MS runtime, 
>you
>cannot use MS's version on Mono.
>
>Piers.
>
> > -----Original Message-----
> > From: bvv [mailto:bvvarma1@rediffmail.com]
> > Sent: Monday, December 30, 2002 7:50 AM
> > To: Piers Haken; mono-list@ximian.com
> > Subject: Re: RE: [Mono-list] Microsoft's compiler with 
>mono's
> > corlib! - Issues!
> >
> >
> > Hi Piers,
> >
> > Could you explain what this tight coupling is?
> > I was thinking that since all mscorlib class interfaces are 
>part
> > of the ECMA standard it doesn't matter how you implement them 
>as
> > long as you provide all the necessary classes as per the spec. 
>In
> > which case i should ideally be able to mix & match the 
>corlibs
> > between different .Net runtimes.
> >
> > Correct me if i'm wrong please
> >
> > Thanks
> >
> > On Sun, 29 Dec 2002 Piers Haken wrote :
> > > > -----Original Message-----
> > > > From: bvv [mailto:bvvarma1@rediffmail.com]
> > > > Sent: Saturday, December 28, 2002 6:41 AM
> > > > To: mono-list@ximian.com
> > > > Subject: [Mono-list] Microsoft's compiler with mono's
> > >corlib!
> > > > - Issues!
> > > >
> > > >
> > > > Tried to compile and run a helloworld written in C# using 
>the
> > >MS
> > > > compiler but mono's corlib.
> > >
> > >
> > >You cannot do this. The corlibs and runtimes are very 
>tightly
> > >bound. You
> > >cannot mix & match.
> > >
> > >Piers.
> >
> >
> >