[iOS] Generate unique class name for MonoDeadLetter

[steveisok]

In library mode, it is possible to have multiple shared libraries (runtimes) loaded in the same process. On iOS, we have a small bit of objc to make sure we know when threads die so we can properly detach the runtime. Unfortunately, the class name we use is not unique and results in a crash when calling into a 2nd library.

This change makes the class name partially unique to avoid such a circumstance.

[vargaz]

Multiple mono runtimes can't really coexist in the same process.

[steveisok]

Multiple mono runtimes can't really coexist in the same process.

From what we've found, as long as you enable signal chaining, it will work.

[steveisok]

@lateralusX in testing two libraries, xcode found two instances of

runtime/src/native/libs/System.Native/pal_autoreleasepool.m

Line 7 in f447532

@interface PlaceholderObject : NSObject

Does that need the same treatment as MonoDeadLetter?

[lateralusX]

@lateralusX in testing two libraries, xcode found two instances of

runtime/src/native/libs/System.Native/pal_autoreleasepool.m

Line 7 in f447532

@interface PlaceholderObject : NSObject

Does that need the same treatment as MonoDeadLetter?

Did you get build/package errors or runtime load errors due to that?

[steveisok]

Did you get build/package errors or runtime load errors due to that?

No, it just says there are two and it'll be random which one you get.

[lateralusX]

No, it just says there are two and it'll be random which one you get.

But when do you get the error, when you are packing the two libraries into the same app or at runtime when you load the second library?

[steveisok]

But when do you get the error, when you are packing the two libraries into the same app or at runtime when you load the second library?

It's right away. Must be the way obj-c manages its symbols?