Fixed the selection of a virtual table to call virtual methods through in the C# generator.

Fixes https://github.com/mono/CppSharp/issues/703.

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

src/Generator/Generators/CSharp/CSharpSources.cs

@@ -2515,8 +2515,12 @@ namespace CppSharp.Generators.CSharp
             out string delegateId)
         {
             var i = VTables.GetVTableIndex(method.OriginalFunction ?? method, @class);
-            WriteLine("var {0} = *(void**) ((IntPtr) __OriginalVTables[0] + {1} * {2});",
+            int vtableIndex = 0;
-                Helpers.SlotIdentifier, i, Context.TargetInfo.PointerWidth / 8);
+            if (Context.ParserOptions.IsMicrosoftAbi)
+                vtableIndex = @class.Layout.VFTables.IndexOf(@class.Layout.VFTables.Where(
+                    v => v.Layout.Components.Any(c => c.Method.OriginalPtr == method.OriginalPtr)).First());
+            WriteLine("var {0} = *(void**) ((IntPtr) __OriginalVTables[{1}] + {2} * {3});",
+                Helpers.SlotIdentifier, vtableIndex, i, Context.TargetInfo.PointerWidth / 8);
             if (method.IsDestructor && @class.IsAbstract)
             {
                 WriteLine("if ({0} != null)", Helpers.SlotIdentifier);

tests/CSharp/CSharp.Tests.cs

@@ -627,6 +627,29 @@ public unsafe class CSharpTests : GeneratorTestFixture
         }
     }
 
+    [Test]
+    public void TestStackOverflowOnVirtualCall()
+    {
+        using (var hasMissingObjectOnVirtualCall = new HasMissingObjectOnVirtualCall())
+        {
+            using (var missingObjectOnVirtualCall = new MissingObjectOnVirtualCall())
+            {
+                hasMissingObjectOnVirtualCall.SetMissingObjectOnVirtualCall(missingObjectOnVirtualCall);
+                hasMissingObjectOnVirtualCall.MakeMissingObjectOnVirtualCall();
+            }
+        }
+    }
+
+    [Test]
+    public void TestAbstractImplementatonsInPrimaryAndSecondaryBases()
+    {
+        using (var implementsAbstractsFromPrimaryAndSecondary = new ImplementsAbstractsFromPrimaryAndSecondary())
+        {
+            Assert.That(implementsAbstractsFromPrimaryAndSecondary.AbstractInPrimaryBase, Is.EqualTo(101));
+            Assert.That(implementsAbstractsFromPrimaryAndSecondary.AbstractInSecondaryBase, Is.EqualTo(5));
+        }
+    }
+
     private class OverrideVirtualWithString : HasVirtualTakesReturnsProblematicTypes
     {
         public override string VirtualTakesAndReturnsString(string c)
@@ -647,17 +670,4 @@ public unsafe class CSharpTests : GeneratorTestFixture
             return base.HasPointerToEnumInParam(pointerToEnum);
         }
     }
-
+}
-    [Test]
-    public void TestStackOverflowOnVirtualCall()
-    {
-        using (var hasMissingObjectOnVirtualCall = new HasMissingObjectOnVirtualCall())
-        {
-            using (var missingObjectOnVirtualCall = new MissingObjectOnVirtualCall())
-            {
-                hasMissingObjectOnVirtualCall.SetMissingObjectOnVirtualCall(missingObjectOnVirtualCall);
-                hasMissingObjectOnVirtualCall.MakeMissingObjectOnVirtualCall();
-            }
-        }
-    }
-}

tests/CSharp/CSharp.cpp

@@ -1221,3 +1221,21 @@ void HasMissingObjectOnVirtualCall::setMissingObjectOnVirtualCall(MissingObjectO
 {
     stackOverflowOnVirtualCall = value;
 }
+
+ImplementsAbstractsFromPrimaryAndSecondary::ImplementsAbstractsFromPrimaryAndSecondary()
+{
+}
+
+ImplementsAbstractsFromPrimaryAndSecondary::~ImplementsAbstractsFromPrimaryAndSecondary()
+{
+}
+
+int ImplementsAbstractsFromPrimaryAndSecondary::abstractInPrimaryBase()
+{
+    return 101;
+}
+
+int ImplementsAbstractsFromPrimaryAndSecondary::abstractInSecondaryBase()
+{
+    return 5;
+}

tests/CSharp/CSharp.h

@@ -1091,3 +1091,24 @@ public:
 private:
     MissingObjectOnVirtualCall* stackOverflowOnVirtualCall;
 };
+
+class DLL_API AbstractPrimaryBase
+{
+public:
+    virtual int abstractInPrimaryBase() = 0;
+};
+
+class DLL_API AbstractSecondaryBase
+{
+public:
+    virtual int abstractInSecondaryBase() = 0;
+};
+
+class DLL_API ImplementsAbstractsFromPrimaryAndSecondary : public AbstractPrimaryBase, public AbstractSecondaryBase
+{
+public:
+    ImplementsAbstractsFromPrimaryAndSecondary();
+    ~ImplementsAbstractsFromPrimaryAndSecondary();
+    virtual int abstractInPrimaryBase();
+    virtual int abstractInSecondaryBase();
+};