private static int ILStubCache_GCTransition_NoGCTransition(int expected)
{
// This test uses a callback marked UnmanagedCallersOnly as a way to verify that
// SuppressGCTransition is taken into account when caching IL stubs.
// It calls functions with the same signature, differing only in SuppressGCTransition.
// When calling an UnmanagedCallersOnly method, the runtime validates that the GC is in
// pre-emptive mode. If not, it throws a fatal error that cannot be caught and crashes.
Console.WriteLine($"{nameof(ILStubCache_GCTransition_NoGCTransition)} ({expected}) ...");
int n;
void *cb = (delegate * unmanaged[Cdecl] < int, int >) & ReturnInt;
// Call function that does not have SuppressGCTransition
SuppressGCTransitionNative.InvokeCallbackVoidPtr_Inline_GCTransition(cb, &n);
Assert.AreEqual(expected++, n);
// Call function with same (blittable) signature, but with SuppressGCTransition.
// IL stub should not be re-used, GC transition not should occur, and callback invocation should fail.
SuppressGCTransitionNative.InvokeCallbackVoidPtr_Inline_NoGCTransition(cb, &n);
Assert.AreEqual(expected++, n);
// Call function that does not have SuppressGCTransition
SuppressGCTransitionNative.InvokeCallbackVoidPtr_NoInline_GCTransition(cb, &n);
Assert.AreEqual(expected++, n);
// Call function with same (non-blittable) signature, but with SuppressGCTransition
// IL stub should not be re-used, GC transition not should occur, and callback invocation should fail.
expected = n + 1;
SuppressGCTransitionNative.InvokeCallbackVoidPtr_NoInline_NoGCTransition(cb, &n);
Assert.AreEqual(expected++, n);
return(n + 1);
}
