Add support for interface dispatch to have a codepath that supports resolution from a metadata token

- Instead of an interface/slot pair
- Cell information is now consolidated into a structure instead of being passed around as a tuple of interface/slot
- Encoding is more complex to avoid bloating the data format
- In addition to interface dispatch, the logic is also able to perform vtable dispatch
- Add support for the concept of dynamic modules
- A dynamic module provides a set of callbacks that are special around the behavior of interface dispatch
- ModuleList associates a DynamicModule with normal module. At some point we will consolidate the DynamicModule with the ModuleManager

Miscellaneous changes
- New variant of LockFreeReaderHashtable to be used with native pointers.
- Support for a cloned type to be cloned based on a direct pointer instead of an indirection

[tfs-changeset: 1630711]

2 files changed, 22 insertions, 0 deletions

diff --git a/src/Native/Runtime/amd64/StubDispatch.S b/src/Native/Runtime/amd64/StubDispatch.S
index 2df605a35..bde82f42f 100644
--- a/src/Native/Runtime/amd64/StubDispatch.S
+++ b/src/Native/Runtime/amd64/StubDispatch.S
@@ -68,6 +68,12 @@ DEFINE_INTERFACE_DISPATCH_STUB 16
 DEFINE_INTERFACE_DISPATCH_STUB 32
 DEFINE_INTERFACE_DISPATCH_STUB 64
 
+;; Stub dispatch routine for dispatch to a vtable slot
+LEAF_ENTRY RhpVTableOffsetDispatch, _TEXT
+        // UNIXTODO: Implement this function
+        int 3
+LEAF_END RhpTailCallTLSDispatchCell, _TEXT
+
 // Initial dispatch on an interface when we don't have a cache yet.
 LEAF_ENTRY RhpInitialInterfaceDispatch, _TEXT
 ALTERNATE_ENTRY RhpInitialDynamicInterfaceDispatch
diff --git a/src/Native/Runtime/amd64/StubDispatch.asm b/src/Native/Runtime/amd64/StubDispatch.asm
index c718c6b20..6449739ee 100644
--- a/src/Native/Runtime/amd64/StubDispatch.asm
+++ b/src/Native/Runtime/amd64/StubDispatch.asm
@@ -109,6 +109,22 @@ DEFINE_INTERFACE_DISPATCH_STUB 16
 DEFINE_INTERFACE_DISPATCH_STUB 32
 DEFINE_INTERFACE_DISPATCH_STUB 64
 
+;; Stub dispatch routine for dispatch to a vtable slot
+LEAF_ENTRY RhpVTableOffsetDispatch, _TEXT
+        ;; r10 currently contains the indirection cell address. 
+        ;; load rax to point to the vtable offset (which is stored in the m_pCache field).
+        mov     rax, [r10 + OFFSETOF__InterfaceDispatchCell__m_pCache]
+
+        ;; Load the EEType from the object instance in rcx, and add it to the vtable offset
+        ;; to get the address in the vtable of what we want to dereference
+        add     rax, [rcx]
+
+        ;; Load the target address of the vtable into rax
+        mov     rax, [rax]
+
+        TAILJMP_RAX
+LEAF_END RhpVTableOffsetDispatch, _TEXT
+
 
 ;; Initial dispatch on an interface when we don't have a cache yet.
 LEAF_ENTRY RhpInitialInterfaceDispatch, _TEXT