Delegate Marshalling

Initital support for delegate marshalling.

- Enabled only in full runtime
- Doesn't work in non-windows platforms
- Only supports open static delegates

2 files changed, 123 insertions, 0 deletions

diff --git a/src/Native/Runtime/amd64/InteropThunksHelpers.S b/src/Native/Runtime/amd64/InteropThunksHelpers.S
new file mode 100644
index 000000000..e6b7c67ce
--- /dev/null
+++ b/src/Native/Runtime/amd64/InteropThunksHelpers.S
@@ -0,0 +1,22 @@
+// 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.
+
+.intel_syntax noprefix
+#include <unixasmmacros.inc>
+
+//TODO: Implement these stub method for non-windows
+
+LEAF_ENTRY RhpCommonStub, _TEXT
+    int 3
+LEAF_END RhpCommonStub, _TEXT
+
+
+LEAF_ENTRY RhpGetCommonStubAddress, _TEXT
+    int 3
+LEAF_END RhpGetCommonStubAddress, _TEXT
+
+
+LEAF_ENTRY RhpGetCurrentThunkContext, _TEXT
+    int 3
+LEAF_END RhpGetCurrentThunkContext, _TEXT
\ No newline at end of file
diff --git a/src/Native/Runtime/amd64/InteropThunksHelpers.asm b/src/Native/Runtime/amd64/InteropThunksHelpers.asm
new file mode 100644
index 000000000..eb694cf73
--- /dev/null
+++ b/src/Native/Runtime/amd64/InteropThunksHelpers.asm
@@ -0,0 +1,101 @@
+;; 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.
+
+
+;; -----------------------------------------------------------------------------------------------------------
+;;#include "asmmacros.inc"
+;; -----------------------------------------------------------------------------------------------------------
+
+LEAF_ENTRY macro Name, Section
+    Section segment para 'CODE'
+    align   16
+    public  Name
+    Name    proc
+endm
+
+LEAF_END macro Name, Section
+    Name    endp
+    Section ends
+endm
+
+;  - TAILCALL_RAX: ("jmp rax") should be used for tailcalls, this emits an instruction 
+;            sequence which is recognized by the unwinder as a valid epilogue terminator
+TAILJMP_RAX TEXTEQU <DB 048h, 0FFh, 0E0h>
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;  DATA SECTIONS  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+_tls_array                          equ 58h     ;; offsetof(TEB, ThreadLocalStoragePointer)
+
+POINTER_SIZE                        equ 08h
+
+;; TLS variables
+_TLS    SEGMENT ALIAS(".tls$")
+    ThunkParamSlot  DQ 0000000000000000H
+_TLS    ENDS
+
+EXTRN   _tls_index:DWORD
+
+
+;;;;;;;;;;;;;;;;;;;;;;; Interop Thunks Helpers ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;;
+;; RhpCommonStub
+;;
+LEAF_ENTRY RhpCommonStub, _TEXT
+        ;; There are arbitrary callers passing arguments with arbitrary signatures.
+        ;; Custom calling convention:
+        ;;      r10: pointer to the current thunk's data block (data contains 2 pointer values: context + target pointers)
+
+        ;; Save context data into the ThunkParamSlot thread-local variable
+        ;; A pointer to the delegate and function pointer for open static delegate should have been saved in the thunk's context cell during thunk allocation
+        mov     [rsp + 8], rcx                                     ;; Save rcx in a home scratch location. Pushing the 
+                                                                   ;; register on the stack will break callstack unwind
+        mov     ecx, [_tls_index]
+        mov     r11, gs:[_tls_array]
+        mov     rax, [r11 + rcx * POINTER_SIZE]
+
+        mov     rcx, [rsp + 8]                                     ;; Restore rcx
+        
+        ;; rax = base address of TLS data
+        ;; r10 = address of context cell in thunk's data
+        ;; r11 = trashed
+        ;; r12 = trashed
+
+        ;; store thunk address in thread static
+        mov     r11, [r10]
+        xor     r8, r8
+        mov     r8d, SECTIONREL ThunkParamSlot
+        mov     [rax + r8], r11                 ;;   ThunkParamSlot <- context slot data
+
+        ;; jump to the target
+        mov     rax, [r10 + POINTER_SIZE]
+        TAILJMP_RAX
+LEAF_END RhpCommonStub, _TEXT
+
+
+;;
+;; IntPtr RhpGetCommonStubAddress()
+;;
+LEAF_ENTRY RhpGetCommonStubAddress, _TEXT
+        lea     rax, [RhpCommonStub]
+        ret
+LEAF_END RhpGetCommonStubAddress, _TEXT
+
+
+;;
+;; IntPtr RhpGetCurrentThunkContext()
+;;
+LEAF_ENTRY RhpGetCurrentThunkContext, _TEXT
+        mov     r10d, [_tls_index]
+        mov     r11, gs:[_tls_array]
+        mov     r10, [r11 + r10 * POINTER_SIZE]
+        xor     r8, r8 
+        mov     r8d, SECTIONREL ThunkParamSlot
+        mov     rax, [r10 + r8]                 ;;   rax <- ThunkParamSlot
+        ret
+LEAF_END RhpGetCurrentThunkContext, _TEXT
+
+
+end