A small jit changes for Arm64 apple.

src/coreclr/src/jit/ee_il_dll.cpp

@@ -426,9 +426,14 @@ unsigned Compiler::eeGetArgSize(CORINFO_ARG_LIST_HANDLE list, CORINFO_SIG_INFO*
     }
     else
     {
+#if !defined(OSX_ARM64_ABI)
         unsigned argSize = sizeof(int) * genTypeStSz(argType);
+        argSize = roundUp(argSize, TARGET_POINTER_SIZE);
+#else
+        unsigned argSize = genTypeSize(argType);
+#endif
         assert(0 < argSize && argSize <= sizeof(__int64));
-        return roundUp(argSize, TARGET_POINTER_SIZE);
+        return argSize;
     }
 #endif
 }

src/coreclr/src/jit/lclvars.cpp

@@ -1029,7 +1029,7 @@ void Compiler::lvaInitUserArgs(InitVarDscInfo* varDscInfo)
             assert((argSize % TARGET_POINTER_SIZE) == 0);
             assert((varDscInfo->stackArgSize % TARGET_POINTER_SIZE) == 0);
 #endif // !OSX_ARM64_ABI
-
+            JITDUMP("set user arg V%02u offset to %u\n", varDscInfo->stackArgSize);
             varDsc->SetStackOffset(varDscInfo->stackArgSize);
             varDscInfo->stackArgSize += argSize;
 #endif // FEATURE_FASTTAILCALL

src/coreclr/src/jit/morph.cpp

@@ -2719,7 +2719,7 @@ void Compiler::fgInitArgInfo(GenTreeCall* call)
         *insertionPoint = gtNewCallArgs(arg);
 #else  // !defined(TARGET_X86)
         // All other architectures pass the cookie in a register.
-        call->gtCallArgs       = gtPrependNewCallArg(arg, call->gtCallArgs);
+        call->gtCallArgs = gtPrependNewCallArg(arg, call->gtCallArgs);
 #endif // defined(TARGET_X86)
 
         nonStandardArgs.Add(arg, REG_PINVOKE_COOKIE_PARAM);
@@ -2958,8 +2958,6 @@ void Compiler::fgInitArgInfo(GenTreeCall* call)
         bool passUsingFloatRegs;
 #if !defined(OSX_ARM64_ABI)
         unsigned argAlignBytes = TARGET_POINTER_SIZE;
-#else
-        unsigned argAlignBytes = TARGET_POINTER_SIZE; // TODO-OSX-ARM64: change it after other changes are merged.
 #endif
         unsigned             size          = 0;
         unsigned             byteSize      = 0;
@@ -3211,6 +3209,21 @@ void Compiler::fgInitArgInfo(GenTreeCall* call)
         assert(size != 0);
         assert(byteSize != 0);
 
+#if defined(OSX_ARM64_ABI)
+        // Arm64 Apple has a special ABI for passing small size arguments on stack,
+        // bytes are aligned to 1-byte, shorts to 2-byte, int/float to 4-byte, etc.
+        // It means passing 8 1-byte arguments on stack can take as small as 8 bytes.
+        unsigned argAlignBytes;
+        if (isStructArg)
+        {
+            argAlignBytes = TARGET_POINTER_SIZE;
+        }
+        else
+        {
+            argAlignBytes = byteSize;
+        }
+#endif
+
         //
         // Figure out if the argument will be passed in a register.
         //

src/tests/Interop/PInvoke/Primitives/Int/PInvokeIntNative.cpp

@@ -50,6 +50,28 @@ extern "C" DLL_EXPORT int STDMETHODCALLTYPE Marshal_InMany(/*[in]*/short i1, sho
     return i1 + i2 + i3 + i4 + i5 + i6 + i7 + i8 + i9 + i10 + i11 + i12 + i13 + i14 + i15;
 }
 
+extern "C" DLL_EXPORT int STDMETHODCALLTYPE Marshal_InMany_InOutPointer(/*[in]*/short i1, short i2, short i3, short i4, short i5, short i6, short i7, short i8, short i9, short i10, short i11, unsigned char i12, unsigned char i13, int i14, short i15, /*[in,out]*/int *pintValue)
+{
+    //Check the input
+    if(i1 != 1 || i2 != 2 || i3 != 3 || i4 != 4 || i5 != 5 || i6 != 6 || i7 != 7 || i8 != 8 || i9 != 9 || i10 != 10 || i11 != 11 || i12 != 12 || i13 != 13 || i14 != 14 || i15 != 15 || (*pintValue != 1000))
+    {
+        printf("Error in Function Marshal_InMany_InOutPointer(Native Client)\n");
+
+        //Expected
+        printf("Expected: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 1000\n");
+
+        //Actual
+        printf("Actual: %hi, %hi, %hi, %hi, %hi, %hi, %hi, %hi, %hi, %hi, %hi, %i, %i, %i, %hi, %i\n", i1, i2, i3, i4, i5, i6, i7, i8, i9, i10, i11, (int)i12, (int)i13, i14, i15, *pintValue);
+
+        //Return the error value instead if verification failed
+        return intErrReturn;
+    }
+
+    *pintValue = 2000;
+
+    return i1 + i2 + i3 + i4 + i5 + i6 + i7 + i8 + i9 + i10 + i11 + i12 + i13 + i14 + i15;
+}
+
 extern "C" DLL_EXPORT int STDMETHODCALLTYPE Marshal_InOut(/*[In,Out]*/int intValue)
 {
     //Check the input

src/tests/Interop/PInvoke/Primitives/Int/PInvokeIntTest.cs

@@ -26,6 +26,9 @@ class ClientPInvokeIntNativeTest
 
     [DllImport("PInvokeIntNative")]
     private static extern int Marshal_InMany([In]short i1, [In]short i2, [In]short i3, [In]short i4, [In]short i5, [In]short i6, [In]short i7, [In]short i8, [In]short i9, [In]short i10, [In]short i11, [In]byte i12, [In]byte i13, [In]int i14, [In]short i15);
+
+    [DllImport("PInvokeIntNative")]
+    private static extern int Marshal_InMany_InOutPointer([In]short i1, [In]short i2, [In]short i3, [In]short i4, [In]short i5, [In]short i6, [In]short i7, [In]short i8, [In]short i9, [In]short i10, [In]short i11, [In]byte i12, [In]byte i13, [In]int i14, [In]short i15, ref int pintValue);
 
 
     public static int Main(string[] args)
@@ -107,6 +110,18 @@ public static int Main(string[] args)
             failures++;
             Console.WriteLine("InMany return value is wrong");
         }
+
+        int int7 = intManaged;
+        if(120 != Marshal_InMany_InOutPointer(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, ref int7))
+        {
+            failures++;
+            Console.WriteLine("InMany_InOutPointer return value is wrong");
+        }
+        if (intNative != int7)
+        {
+            failures++;
+            Console.WriteLine("InMany_InOutPointer byref value is wrong.");
+        }
 
         return 100 + failures;
     }