This change implements CastableObject support. The work was done by David Wrighton, I have added support for x86 and ARM32 and investigated few general issues that surfaced during testing.

1. Logic to convert interface dispatch to use universal transition thunk instead of managedcalloutthunk. (This allows interface dispatch to safely throw exceptions if it needs to.) (This is implemented for all platforms)
2. Poor man’s interface type equivalence to allow the new ICastableObject interface to be called directly from the runtime instead of building a specialized calling routine. (We should probably consider implementing the general thing, but this shelveset is big enough as it is.)
3. Small feature adds around COFF emission of pdb records to allow the runtime to have an interface dispatch in it.
4. New CastableObject class
5. Tweak to reflection to allow both ICastable and CastableObject interface dispatch routines to work.
6. Test case for CastableObject
7. Assembly stubs and thunks to make castable object implementation work.

[tfs-changeset: 1630177]

1 files changed, 79 insertions, 8 deletions

diff --git a/src/Native/Runtime/i386/StubDispatch.asm b/src/Native/Runtime/i386/StubDispatch.asm
index 3e8426311..5153d73b8 100644
--- a/src/Native/Runtime/i386/StubDispatch.asm
+++ b/src/Native/Runtime/i386/StubDispatch.asm
@@ -15,6 +15,77 @@ ifdef FEATURE_CACHED_INTERFACE_DISPATCH
 
 EXTERN RhpCidResolve : PROC
 EXTERN _RhpUniversalTransition_DebugStepTailCall@0 : PROC
+EXTERN RhpCastableObjectResolve : PROC
+EXTERN _RhpCheckedAssignRefEDX : PROC
+
+EXTERN  _t_TLS_DispatchCell:DWORD
+EXTERN  __tls_index:DWORD
+
+GET_TLS_DISPATCH_CELL macro
+        ASSUME fs : NOTHING
+        mov     eax, [__tls_index]
+        add     eax, eax
+        add     eax, eax
+        add     eax, fs:[__tls_array]
+        mov     eax, [eax]
+        mov     eax, [eax + SECTIONREL _t_TLS_DispatchCell]
+endm
+
+_RhpGetTailCallTLSDispatchCell proc public
+        lea     eax, RhpTailCallTLSDispatchCell
+        ret
+_RhpGetTailCallTLSDispatchCell endp
+
+RhpTailCallTLSDispatchCell proc public
+        ;; Load the dispatch cell out of the TLS variable
+        GET_TLS_DISPATCH_CELL
+
+        ;; Tail call to the target of the dispatch cell
+        jmp     dword ptr [eax]
+RhpTailCallTLSDispatchCell endp
+
+_RhpGetCastableObjectDispatchHelper_TailCalled proc public
+        lea     eax, RhpCastableObjectDispatchHelper_TailCalled
+        ret
+_RhpGetCastableObjectDispatchHelper_TailCalled endp
+
+RhpCastableObjectDispatchHelper_TailCalled proc public
+        ;; Load the dispatch cell out of the TLS variable
+        GET_TLS_DISPATCH_CELL
+        jmp     RhpCastableObjectDispatchHelper
+RhpCastableObjectDispatchHelper_TailCalled endp
+
+RhpCastableObjectDispatchHelper proc public
+        push    ebp
+        mov     ebp, esp
+        ;; TODO! Implement fast lookup helper to avoid the universal transition each time we
+        ;; hit a CastableObject
+
+        ;; If the initial lookup fails, call into managed under the universal thunk
+        ;; to run the full lookup routine
+
+        ;; indirection cell address is in EAX, it will be passed by
+        ;; the universal transition thunk as an argument to RhpCastableObjectResolve
+        push    eax
+        lea     eax, RhpCastableObjectResolve
+        push    eax
+        jmp     _RhpUniversalTransition_DebugStepTailCall@0
+RhpCastableObjectDispatchHelper endp
+
+_RhpGetCastableObjectDispatchHelper proc public
+        lea     eax, RhpCastableObjectDispatchHelper
+        ret
+_RhpGetCastableObjectDispatchHelper endp
+
+_RhpGetCacheForCastableObject proc public
+        mov     eax, [ecx+4]
+        ret
+_RhpGetCacheForCastableObject endp
+
+_RhpSetCacheForCastableObject proc public
+        lea     ecx, [ecx+4]
+        jmp     _RhpCheckedAssignRefEDX ;; Is this the correct form for tailcall?
+_RhpSetCacheForCastableObject endp
 
 
 ;; Macro that generates code to check a single cache entry.
@@ -64,7 +135,7 @@ CurrentEntry = CurrentEntry + 1
         ;; indirection cell using the back pointer in the cache block
         mov     eax, [eax + OFFSETOF__InterfaceDispatchCache__m_pCell]
         pop     ebx
-        jmp     InterfaceDispatchCacheMiss
+        jmp     RhpInterfaceDispatchSlow
 
     StubName endp
 
@@ -81,19 +152,19 @@ DEFINE_INTERFACE_DISPATCH_STUB 32
 DEFINE_INTERFACE_DISPATCH_STUB 64
 
 ;; Shared out of line helper used on cache misses.
-    InterfaceDispatchCacheMiss proc
+RhpInterfaceDispatchSlow proc
 ;; eax points at InterfaceDispatchCell
 
-;; Setup call to Universal Transition thunk
+        ;; Setup call to Universal Transition thunk
         push        ebp
         mov         ebp, esp
         push        eax   ; First argument (Interface Dispatch Cell)
         lea         eax, [RhpCidResolve]
         push        eax ; Second argument (RhpCidResolve)
 
-;; Jump to Universal Transition
+        ;; Jump to Universal Transition
         jmp         _RhpUniversalTransition_DebugStepTailCall@0
-    InterfaceDispatchCacheMiss endp
+RhpInterfaceDispatchSlow endp
 
 ;; Out of line helper used when we try to interface dispatch on a null pointer. Sets up the stack so the
 ;; debugger gives a reasonable stack trace.
@@ -106,12 +177,12 @@ RhpInterfaceDispatchNullReference endp
 
 
 ;; Initial dispatch on an interface when we don't have a cache yet.
-    RhpInitialInterfaceDispatch proc public
+_RhpInitialInterfaceDispatch proc public
     ALTERNATE_ENTRY RhpInitialDynamicInterfaceDispatch
 
-        jmp InterfaceDispatchCacheMiss
+        jmp RhpInterfaceDispatchSlow
 
-    RhpInitialInterfaceDispatch endp
+_RhpInitialInterfaceDispatch endp
 
 
 endif ;; FEATURE_CACHED_INTERFACE_DISPATCH