public unsafe IntPtr UpdateFloatingDictionary(IntPtr context, IntPtr dictionaryPtr)
{
IntPtr newFloatingDictionary;
bool isNewlyAllocatedDictionary;
bool isTypeContext = context != dictionaryPtr;
if (isTypeContext)
{
// Look for the exact base type that owns the dictionary. We may be having
// a virtual method run on a derived type and the generic lookup are performed
// on the base type's dictionary.
MethodTable* pEEType = (MethodTable*)context.ToPointer();
context = (IntPtr)EETypeCreator.GetBaseEETypeForDictionaryPtr(pEEType, dictionaryPtr);
}
using (LockHolder.Hold(_typeLoaderLock))
{
// Check if some other thread already allocated a floating dictionary and updated the fixed portion
if (*(IntPtr*)dictionaryPtr != IntPtr.Zero)
return *(IntPtr*)dictionaryPtr;
try
{
if (t_isReentrant)
Environment.FailFast("Reentrant update to floating dictionary");
t_isReentrant = true;
newFloatingDictionary = TypeBuilder.TryBuildFloatingDictionary(context, isTypeContext, dictionaryPtr, out isNewlyAllocatedDictionary);
t_isReentrant = false;
}
catch
{
// Catch and rethrow any exceptions instead of using finally block. Otherwise, filters that are run during
// the first pass of exception unwind may hit the re-entrancy fail fast above.
// TODO: Convert this to filter for better diagnostics once we switch to Roslyn
t_isReentrant = false;
throw;
}
}
if (newFloatingDictionary == IntPtr.Zero)
{
Environment.FailFast("Unable to update floating dictionary");
return IntPtr.Zero;
}
// The pointer to the floating dictionary is the first slot of the fixed dictionary.
if (Interlocked.CompareExchange(ref *(IntPtr*)dictionaryPtr, newFloatingDictionary, IntPtr.Zero) != IntPtr.Zero)
{
// Some other thread beat us and updated the pointer to the floating dictionary.
// Free the one allocated by the current thread
if (isNewlyAllocatedDictionary)
MemoryHelpers.FreeMemory(newFloatingDictionary);
}
return *(IntPtr*)dictionaryPtr;
}
public static unsafe IntPtr GetDictionary(this RuntimeTypeHandle rtth)
{
return(EETypeCreator.GetDictionary(rtth.ToEETypePtr()));
}
