…oke (#18115)

[2019-10] [mini] Fix delegate trampoline virtual call via delgate Invoke

If we need to jit the Invoke method of a delegate, we get `tramp_info` with a
NULL method.

Background: normally when we create a delegate around a virtual method,
`handle_delegate_ctor` will just create a virtual invoke trampoline with
`mono_arch_get_delegate_virtual_invoke_impl` which doesn't get here.  But if
we're asked to compile the delegate's `Invoke` method, then `compile_special ()`
will create a `tramp_info` with a null method, and return a delegate trampoline.

That's the case here - we had
```
  var del = SomeDelegate(obj.VirtualMethod);
  var invoke_method = del.GetType().GetMethod ("Invoke");
  invoke_method.Invoke (del, args);
```
or
```
  var del = SomeDelegate(obj.VirtualMethod);
  var another_del = OtherDelegate (del.Invoke);
  another_del (args);
```

in both cases, we end up in mono_delegate_trampoline with `tramp_info->method == NULL`.

in the second case the IL is like this:
```
   newobj instance void Derived::'.ctor'
   ldvirtftn instance void class Base::VirtualMethod()
   newobj instance void class SomeDelegate::'.ctor'(object, native int)
```

So `delegate->target` is a derived instance but `delegate->method` is some base
class method.

Addresses #17718



Backport of #18073.

/cc @lambdageek

…mono#18073)

* [mini] Fix delegate trampoline virtual call via delgate Invoke

If we need to jit the Invoke method of a delegate, we get tramp_info with a
NULL method.

Background: normally when we create a delegate around a virtual method,
handle_delegate_ctor will just create a virtual invoke trampoline with
mono_arch_get_delegate_virtual_invoke_impl which doesn't get here.  But if
we're asked to compile the delegate's Invoke method, then compile_special ()
will create a tramp_info with a null method, and return a delegate trampoline.

That's the case here - we had
  var del = SomeDelegate(obj.VirtualMethod);
  var invoke_method = del.GetType().GetMethod ("Invoke");
  invoke_method.Invoke (del, args);
or
  var del = SomeDelegate(obj.VirtualMethod);
  var another_del = OtherDelegate (del.Invoke);
  another_del (args);

in both cases, we end up in mono_delegate_trampoline with tramp_info->method ==
NULL.

in the second case the IL is like this:
   newobj instance void Derived::'.ctor'
   ldvirtftn instance void class Base::VirtualMethod()
   newobj instance void class SomeDelegate::'.ctor'(object, native int)

So delegate->target is a derived instance but delegate->method is some base
class method.

Addresses mono/mono#17718

* [tests] Add tests for compiling delegate's Invoke method

Where the delegate calls a virtual method


Commit migrated from mono/mono@7704bd1

…18073)

* [mini] Fix delegate trampoline virtual call via delgate Invoke

If we need to jit the Invoke method of a delegate, we get tramp_info with a
NULL method.

Background: normally when we create a delegate around a virtual method,
handle_delegate_ctor will just create a virtual invoke trampoline with
mono_arch_get_delegate_virtual_invoke_impl which doesn't get here.  But if
we're asked to compile the delegate's Invoke method, then compile_special ()
will create a tramp_info with a null method, and return a delegate trampoline.

That's the case here - we had
  var del = SomeDelegate(obj.VirtualMethod);
  var invoke_method = del.GetType().GetMethod ("Invoke");
  invoke_method.Invoke (del, args);
or
  var del = SomeDelegate(obj.VirtualMethod);
  var another_del = OtherDelegate (del.Invoke);
  another_del (args);

in both cases, we end up in mono_delegate_trampoline with tramp_info->method ==
NULL.

in the second case the IL is like this:
   newobj instance void Derived::'.ctor'
   ldvirtftn instance void class Base::VirtualMethod()
   newobj instance void class SomeDelegate::'.ctor'(object, native int)

So delegate->target is a derived instance but delegate->method is some base
class method.

Addresses mono#17718

* [tests] Add tests for compiling delegate's Invoke method

Where the delegate calls a virtual method

…8422

[mini] Fix delegate trampoline virtual call via delgate Invoke (mono#18073)

…18073)

* [mini] Fix delegate trampoline virtual call via delgate Invoke

If we need to jit the Invoke method of a delegate, we get tramp_info with a
NULL method.

Background: normally when we create a delegate around a virtual method,
handle_delegate_ctor will just create a virtual invoke trampoline with
mono_arch_get_delegate_virtual_invoke_impl which doesn't get here.  But if
we're asked to compile the delegate's Invoke method, then compile_special ()
will create a tramp_info with a null method, and return a delegate trampoline.

That's the case here - we had
  var del = SomeDelegate(obj.VirtualMethod);
  var invoke_method = del.GetType().GetMethod ("Invoke");
  invoke_method.Invoke (del, args);
or
  var del = SomeDelegate(obj.VirtualMethod);
  var another_del = OtherDelegate (del.Invoke);
  another_del (args);

in both cases, we end up in mono_delegate_trampoline with tramp_info->method ==
NULL.

in the second case the IL is like this:
   newobj instance void Derived::'.ctor'
   ldvirtftn instance void class Base::VirtualMethod()
   newobj instance void class SomeDelegate::'.ctor'(object, native int)

So delegate->target is a derived instance but delegate->method is some base
class method.

Addresses mono#17718

* [tests] Add tests for compiling delegate's Invoke method

Where the delegate calls a virtual method

…18073)

* [mini] Fix delegate trampoline virtual call via delgate Invoke

If we need to jit the Invoke method of a delegate, we get tramp_info with a
NULL method.

Background: normally when we create a delegate around a virtual method,
handle_delegate_ctor will just create a virtual invoke trampoline with
mono_arch_get_delegate_virtual_invoke_impl which doesn't get here.  But if
we're asked to compile the delegate's Invoke method, then compile_special ()
will create a tramp_info with a null method, and return a delegate trampoline.

That's the case here - we had
  var del = SomeDelegate(obj.VirtualMethod);
  var invoke_method = del.GetType().GetMethod ("Invoke");
  invoke_method.Invoke (del, args);
or
  var del = SomeDelegate(obj.VirtualMethod);
  var another_del = OtherDelegate (del.Invoke);
  another_del (args);

in both cases, we end up in mono_delegate_trampoline with tramp_info->method ==
NULL.

in the second case the IL is like this:
   newobj instance void Derived::'.ctor'
   ldvirtftn instance void class Base::VirtualMethod()
   newobj instance void class SomeDelegate::'.ctor'(object, native int)

So delegate->target is a derived instance but delegate->method is some base
class method.

Addresses mono#17718

* [tests] Add tests for compiling delegate's Invoke method

Where the delegate calls a virtual method

…18073)

* [mini] Fix delegate trampoline virtual call via delgate Invoke

If we need to jit the Invoke method of a delegate, we get tramp_info with a
NULL method.

Background: normally when we create a delegate around a virtual method,
handle_delegate_ctor will just create a virtual invoke trampoline with
mono_arch_get_delegate_virtual_invoke_impl which doesn't get here.  But if
we're asked to compile the delegate's Invoke method, then compile_special ()
will create a tramp_info with a null method, and return a delegate trampoline.

That's the case here - we had
  var del = SomeDelegate(obj.VirtualMethod);
  var invoke_method = del.GetType().GetMethod ("Invoke");
  invoke_method.Invoke (del, args);
or
  var del = SomeDelegate(obj.VirtualMethod);
  var another_del = OtherDelegate (del.Invoke);
  another_del (args);

in both cases, we end up in mono_delegate_trampoline with tramp_info->method ==
NULL.

in the second case the IL is like this:
   newobj instance void Derived::'.ctor'
   ldvirtftn instance void class Base::VirtualMethod()
   newobj instance void class SomeDelegate::'.ctor'(object, native int)

So delegate->target is a derived instance but delegate->method is some base
class method.

Addresses mono#17718

* [tests] Add tests for compiling delegate's Invoke method

Where the delegate calls a virtual method

…8422

[mini] Fix delegate trampoline virtual call via delgate Invoke (mono#18073)

…8422

[mini] Fix delegate trampoline virtual call via delgate Invoke (mono#18073)

…8422

[mini] Fix delegate trampoline virtual call via delgate Invoke (mono#18073)