This fixes debugger step-in in the interface dispatch changes

[tfs-changeset: 1622102]

2 files changed, 35 insertions, 4 deletions

diff --git a/src/Native/Runtime/amd64/StubDispatch.asm b/src/Native/Runtime/amd64/StubDispatch.asm
index b81a35ce4..83ab0a6f1 100644
--- a/src/Native/Runtime/amd64/StubDispatch.asm
+++ b/src/Native/Runtime/amd64/StubDispatch.asm
@@ -7,7 +7,12 @@ include AsmMacros.inc
 
 ifdef FEATURE_CACHED_INTERFACE_DISPATCH
 
+ifdef LEGACY_INTERFACE_DISPATCH
 EXTERN RhpResolveInterfaceMethodCacheMiss : PROC
+endif ;; LEGACY_INTERFACE_DISPATCH
+
+EXTERN RhpCidResolve : PROC
+EXTERN RhpUniversalTransition_DebugStepTailCall : PROC
 
 
 ;; Macro that generates code to check a single cache entry.
@@ -75,6 +80,22 @@ ALTERNATE_ENTRY RhpInitialDynamicInterfaceDispatch
 
 LEAF_END RhpInitialInterfaceDispatch, _TEXT
 
+ifndef LEGACY_INTERFACE_DISPATCH
+;; Cache miss case, call the runtime to resolve the target and update the cache.
+;; Use universal transition helper to allow an exception to flow out of resolution
+LEAF_ENTRY RhpInterfaceDispatchSlow, _TEXT
+        ;; r10 contains indirection cell address, move to r11 where it will be passed by
+        ;; the universal transition thunk as an argument to RhpCidResolve
+        mov r11, r10
+        lea r10, RhpCidResolve
+        jmp RhpUniversalTransition_DebugStepTailCall
+EXTERN RhpCidResolve : PROC
+
+LEAF_END RhpInterfaceDispatchSlow, _TEXT
+endif ;; !LEGACY_INTERFACE_DISPATCH
+
+ifdef LEGACY_INTERFACE_DISPATCH
+;; CORE_RT code, which uses legacy RhpResolveInterfaceCacheMissFunction
 ;; Cache miss case, call the runtime to resolve the target and update the cache.
 NESTED_ENTRY RhpInterfaceDispatchSlow, _TEXT
 
@@ -161,7 +182,7 @@ RIDS_ReservedStack equ 20h + 60h + 40h + 8h     ;; Scratch space, transition fra
         add     rsp, RIDS_ReservedStack
         TAILJMP_RAX
 NESTED_END RhpInterfaceDispatchSlow, _TEXT
-
+endif ;; LEGACY_INTERFACE_DISPATCH
 
 
 
diff --git a/src/Native/Runtime/amd64/UniversalTransition.asm b/src/Native/Runtime/amd64/UniversalTransition.asm
index f2639c7c6..ecc413e77 100644
--- a/src/Native/Runtime/amd64/UniversalTransition.asm
+++ b/src/Native/Runtime/amd64/UniversalTransition.asm
@@ -85,7 +85,9 @@ DISTANCE_FROM_CHILDSP_TO_CALLERSP               equ DISTANCE_FROM_CHILDSP_TO_RET
 ; everything between the base of the ReturnBlock and the top of the StackPassedArgs.
 ;
 
-NESTED_ENTRY RhpUniversalTransition, _TEXT        
+UNIVERSAL_TRANSITION macro FunctionName
+
+NESTED_ENTRY Rhp&FunctionName, _TEXT        
 
         alloc_stack DISTANCE_FROM_CHILDSP_TO_RETADDR
         
@@ -124,7 +126,7 @@ endif ; TRASH_SAVED_ARGUMENT_REGISTERS
         mov  rdx, r11
         lea  rcx, [rsp + DISTANCE_FROM_CHILDSP_TO_RETURN_BLOCK]
         call r10
-LABELED_RETURN_ADDRESS ReturnFromUniversalTransition
+LABELED_RETURN_ADDRESS ReturnFrom&FunctionName
 
         ; restore fp argument registers
         movdqa          xmm0, [rsp + DISTANCE_FROM_CHILDSP_TO_FP_REGS      ]
@@ -146,8 +148,16 @@ LABELED_RETURN_ADDRESS ReturnFromUniversalTransition
 
         TAILJMP_RAX
 
-NESTED_END RhpUniversalTransition, _TEXT
+NESTED_END Rhp&FunctionName, _TEXT
+
+        endm
 
+        ; To enable proper step-in behavior in the debugger, we need to have two instances
+        ; of the thunk. For the first one, the debugger steps into the call in the function, 
+        ; for the other, it steps over it.
+        UNIVERSAL_TRANSITION UniversalTransition
+        UNIVERSAL_TRANSITION UniversalTransition_DebugStepTailCall
+        
 endif
 
 end