Fixed the binding of multiple identical function pointers with a calling convention.

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

src/AST/CppTypePrinter.cs

@@ -89,7 +89,14 @@ namespace CppSharp.AST
                 if (arguments.Count > 0)
                     args = VisitParameters(function.Parameters, hasNames: false);
 
-                return string.Format("{0} (*)({1})", returnType.Visit(this), args);
+                var callingConvention = string.Empty;
+                if (function.CallingConvention != CallingConvention.Default &&
+                    function.CallingConvention != CallingConvention.C)
+                {
+                    string conventionString = function.CallingConvention.ToString();
+                    callingConvention = $"__{conventionString.ToLowerInvariant()} ";
+                }
+                return $"{returnType.Visit(this)} ({callingConvention}*)({args})";
             }
 
             var qual = GetStringQuals(quals, false);

src/Generator/Generators/CLI/CLIMarshal.cs

@@ -488,7 +488,7 @@ namespace CppSharp.Generators.CLI
             return returnType.Visit(this);
         }
 
-        public bool VisitDelegateType(FunctionType function, string type)
+        public bool VisitDelegateType(string type)
         {
             // We marshal function pointer types by calling
             // GetFunctionPointerForDelegate to get a native function
@@ -533,7 +533,7 @@ namespace CppSharp.Generators.CLI
                 var cppTypePrinter = new CppTypePrinter();
                 var cppTypeName = pointer.Visit(cppTypePrinter, quals);
 
-                return VisitDelegateType(function, cppTypeName);
+                return VisitDelegateType(cppTypeName);
             }
 
             Enumeration @enum;
@@ -631,7 +631,7 @@ namespace CppSharp.Generators.CLI
                     cppTypeName = decl.Type.Visit(cppTypePrinter, quals);
                 }
 
-                VisitDelegateType(func, cppTypeName);
+                VisitDelegateType(cppTypeName);
                 return true;
             }
 

src/Generator/Passes/DelegatesPass.cs

@@ -115,7 +115,10 @@ namespace CppSharp.Passes
                     return existingDelegate;
 
                 // Add a new delegate with the calling convention appended to its name
-                delegateName += newFunctionType.CallingConvention;
+                delegateName += '_' + newFunctionType.CallingConvention.ToString();
+                existingDelegate = delegates.SingleOrDefault(t => t.Name == delegateName);
+                if (existingDelegate != null)
+                    return existingDelegate;
             }
 
             var namespaceDelegates = GetDeclContextForDelegates(((Declaration) decl).Namespace);

tests/Common/Common.Tests.cs

@@ -562,6 +562,10 @@ public class CommonTests : GeneratorTestFixture
         var testDelegates = new TestDelegates();
         int value = testDelegates.MarshalAnonymousDelegate(i => i * 2);
         Assert.AreEqual(2, value);
+        int value5 = testDelegates.MarshalAnonymousDelegate5(i => i * 2);
+        Assert.AreEqual(4, value5);
+        int value6 = testDelegates.MarshalAnonymousDelegate6(i => i * 2);
+        Assert.AreEqual(6, value6);
     }
 
     [Test]

tests/Common/Common.cpp

@@ -434,6 +434,16 @@ int (*TestDelegates::MarshalAnonymousDelegate4())(int n)
     return f;
 }
 
+int TestDelegates::MarshalAnonymousDelegate5(int (STDCALL *del)(int))
+{
+    return del(2);
+}
+
+int TestDelegates::MarshalAnonymousDelegate6(int (STDCALL *del)(int))
+{
+    return del(3);
+}
+
 ClassA::ClassA(int value)
 {
     Value = value;

tests/Common/Common.h

@@ -387,6 +387,8 @@ struct DLL_API TestDelegates
     void MarshalAnonymousDelegate2(int (*del)(int n));
     void MarshalAnonymousDelegate3(float (*del)(float n));
     int (*MarshalAnonymousDelegate4())(int n);
+    int MarshalAnonymousDelegate5(int (STDCALL *del)(int n));
+    int MarshalAnonymousDelegate6(int (STDCALL *del)(int n));
 
     void MarshalDelegateInAnotherUnit(DelegateInAnotherUnit del);