// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
// ==--==
//
// Shared (non-architecture specific) portions of a mechanism to perform interface dispatch using an alternate
// mechanism to VSD that does not require runtime generation of code.
//
// ============================================================================

#ifdef FEATURE_CACHED_INTERFACE_DISPATCH

bool InitializeInterfaceDispatch();
void ReclaimUnusedInterfaceDispatchCaches();

// Interface dispatch caches contain an array of these entries. An instance of a cache is paired with a stub
// that implicitly knows how many entries are contained. These entries must be aligned to twice the alignment
// of a pointer due to the synchonization mechanism used to update them at runtime.
struct InterfaceDispatchCacheEntry
{
    EEType *    m_pInstanceType;    // Potential type of the object instance being dispatched on
    void *      m_pTargetCode;      // Method to dispatch to if the actual instance type matches the above
};

// The interface dispatch cache itself. As well as the entries we include the cache size (since logic such as
// cache miss processing needs to determine this value in a synchronized manner, so it can't be contained in
// the owning interface dispatch indirection cell) and a list entry used to link the caches in one of a couple
// of lists related to cache reclamation.
#pragma warning(push)
#pragma warning(disable:4200) // nonstandard extension used: zero-sized array in struct/union
struct InterfaceDispatchCell;
struct InterfaceDispatchCache
{
    InterfaceDispatchCacheHeader m_cacheHeader;
    union
    {
        InterfaceDispatchCache *    m_pNextFree;    // next in free list
#ifndef _AMD64_
        InterfaceDispatchCell  *    m_pCell;        // pointer back to interface dispatch cell - not used for AMD64
#endif
    };
    UInt32                      m_cEntries;
    InterfaceDispatchCacheEntry m_rgEntries[];
};
#pragma warning(pop)

#endif // FEATURE_CACHED_INTERFACE_DISPATCH