different behaviors of mixed-mode assembly under .net/wine-mono/native mono.

[Hin-Tak Leung]

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On Fri, Aug 21, 2015 8:20 PM BST Vincent Povirk wrote:

>> So I have a specific question - how do I go about finding
>> out how the IL code exception comes about?
>> (I have had a couple of patches in either camp so
>> I am not against patching wine or mono, or wine-mono for that matter)
>
>You can set the WINE_MONO_VERBOSE environment variable to a single
>digit greater than 0 to get debugging information related to JIT
>compilation. This should at least tell you exactly which method's IL
>is being rejected.
>

Actually I don't need that - the applicatin itself records the stack trace in its normal xml output as:

Invalid IL code in method1 (int,int,int,uint16,byte[],uint16,byte,byte,uint16[],uint16[],uint16, delegate type1): IL_039a: ldarg.s   12



and

Invalid IL code in method2 (int,int,int[],single,single,single,single,single[2],delegate type1, delegate2): IL_0098: ldarg.s   8



The first one is doing "ldarg.s <the delegate>", while the other is doing "ldarg.s <the single[2]>".

I just noticed one anomaly - the single[2] type should be a single[,] type;
These are according to monodevelop's assembly browser.

>Setting MONO_VERBOSE_METHOD will show debugging information for the
>JIT compilation of a specific method, unfortunately Mono crashes
>trying to parse many of the mangled names that appear in Managed C++
>assemblies, so often this approach does not work for me. I've often
>had to hack the code that checks MONO_VERBOSE_METHOD to special-case a
>specific method name.
>

monodis somehow doesn't show either of those.

>> And a general question: are mixed mode assemblies supposed
>> to work under win32 mono at all, or wine-mono definitely needed?
>> I saw some wine + mono discussions a while ago and
>> I got the impression that mixed mode assemblies are supposed to
>> work with win32 mono somewhat?
>
>There is some support for mixed-mode in win32 mono, but it is disabled
>by default. They are different enough that I would not use win32 mono
>on Windows to learn anything about how well wine-mono "should" work.
>

Is it possible to enable win32 mono's mixed mode support at runtime,
or does it requires a re-compile?

>> The application itself is available as a public download in binary form.
>> But since it mostly works - correctly under .net, and even the
>> illegal IL exception was caught, just not the null constructor.
>> Editing the IL code to put a try+catch around the constructor
>> makes it largely operational too under linux mono, so there is
>> not much of a bug to file; mostly a curiosity why
>> wine-mono doesn't behave like it support mixed-mode fully, or
>> not at all, but something between.
>
>Microsoft's managed C++ compiler has been known to generate IL that
>technically violates ecma 335, or otherwise gives Mono trouble. We
>have hacks in wine-mono for a few of these cases, but it's likely we
>have not addressed all of them.
>
>There are also features used by managed C++, such as "thiscall"
>reverse-pinvokes, which are technically independent of mixed-mode, but
>which are not implemented in wine-mono.

The two ldarg.s look invalid to me, but it is possible that Cecil is getting
confused in the same way as mono.