Specify call convention on function pointers (#173)

* Specify call convention on function pointers * Update example
bottlenoselabs · Jan 8, 2025 · d98fdda · d98fdda
1 parent 2a6a549
commit d98fdda
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diff --git a/src/cs/examples/helloworld/helloworld-app/Generated/AssemblyAttributes.g.cs b/src/cs/examples/helloworld/helloworld-app/Generated/AssemblyAttributes.g.cs
@@ -1,6 +1,6 @@
 // <auto-generated>
-//  This code was generated by the following tool on 2025-01-07 13:23:17 GMT-05:00:
-//      https://github.com/bottlenoselabs/c2cs (v2025-01-07 13:23:17 GMT-05:00)
+//  This code was generated by the following tool on 2025-01-07 22:28:42 GMT-05:00:
+//      https://github.com/bottlenoselabs/c2cs (v2025-01-07 22:28:42 GMT-05:00)
 //
 //  Changes to this file may cause incorrect behavior and will be lost if the code is regenerated.
 // </auto-generated>

diff --git a/src/cs/examples/helloworld/helloworld-app/Generated/Runtime.g.cs b/src/cs/examples/helloworld/helloworld-app/Generated/Runtime.g.cs
@@ -1,5 +1,5 @@
 // <auto-generated>
-//  This code was generated by the following tool on 2025-01-07 13:23:17 GMT-05:00:
+//  This code was generated by the following tool on 2025-01-07 22:28:42 GMT-05:00:
 //      https://github.com/bottlenoselabs/c2cs (v0.0.0.0)
 //
 //  Changes to this file may cause incorrect behavior and will be lost if the code is regenerated.

diff --git a/src/cs/examples/helloworld/helloworld-app/Generated/my_c_library.g.cs b/src/cs/examples/helloworld/helloworld-app/Generated/my_c_library.g.cs
@@ -1,5 +1,5 @@
 // <auto-generated>
-//  This code was generated by the following tool on 2025-01-07 13:23:17 GMT-05:00:
+//  This code was generated by the following tool on 2025-01-07 22:28:42 GMT-05:00:
 //      https://github.com/bottlenoselabs/c2cs (v0.0.0.0)
 //
 //  Changes to this file may cause incorrect behavior and will be lost if the code is regenerated.
@@ -180,9 +180,9 @@ public enum hw_week_day : int
     [StructLayout(LayoutKind.Sequential)]
     public partial struct hw_callback
     {
-        public delegate* unmanaged<CString, void> Pointer;
+        public delegate* unmanaged[Cdecl]<CString, void> Pointer;
 
-        public hw_callback(delegate* unmanaged<CString, void> pointer)
+        public hw_callback(delegate* unmanaged[Cdecl]<CString, void> pointer)
         {
             Pointer = pointer;
         }
@@ -191,9 +191,9 @@ public hw_callback(delegate* unmanaged<CString, void> pointer)
     [StructLayout(LayoutKind.Sequential)]
     public partial struct FnPtr_CString_Void
     {
-        public delegate* unmanaged<CString, void> Pointer;
+        public delegate* unmanaged[Cdecl]<CString, void> Pointer;
 
-        public FnPtr_CString_Void(delegate* unmanaged<CString, void> pointer)
+        public FnPtr_CString_Void(delegate* unmanaged[Cdecl]<CString, void> pointer)
         {
             Pointer = pointer;
         }

diff --git a/src/cs/examples/helloworld/helloworld-app/Program.cs b/src/cs/examples/helloworld/helloworld-app/Program.cs
@@ -90,7 +90,7 @@ private static unsafe void Main()
 
 #if NET5_0_OR_GREATER
     // NOTE: Function pointers need to use the UnmanagedCallersOnly attribute. See https://learn.microsoft.com/en-us/dotnet/api/system.runtime.interopservices.unmanagedcallersonlyattribute?view=net-9.0
-    [UnmanagedCallersOnly]
+    [UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)])]
 #endif
     private static void Callback(CString param)
     {

diff --git a/src/cs/production/c2cs.Tool/GenerateCSharpCode/Generators/GeneratorFunctionPointer.cs b/src/cs/production/c2cs.Tool/GenerateCSharpCode/Generators/GeneratorFunctionPointer.cs
@@ -3,6 +3,8 @@
 
 using System.Collections.Immutable;
 using System.Text;
+using bottlenoselabs.Common.Tools;
+using c2ffi.Data;
 using c2ffi.Data.Nodes;
 using JetBrains.Annotations;
 using Microsoft.Extensions.Logging;
@@ -75,7 +77,19 @@ private static string GetFunctionPointerTypeNameCSharp(
         var parameterTypesAndReturnTypeString = string.IsNullOrEmpty(parameterTypesString)
             ? returnTypeString
             : $"{parameterTypesString}, {returnTypeString}";
-        return $"delegate* unmanaged<{parameterTypesAndReturnTypeString}>";
+
+#pragma warning disable IDE0072
+        // ReSharper disable once SwitchExpressionHandlesSomeKnownEnumValuesWithExceptionInDefault
+        var callingConvention = node.CallingConvention switch
+#pragma warning restore IDE0072
+        {
+            CFunctionCallingConvention.Cdecl => "Cdecl",
+            CFunctionCallingConvention.FastCall => "Fastcall",
+            CFunctionCallingConvention.StdCall => "Stdcall",
+            _ => throw new ToolException($"Unknown calling convention for function pointer '{node.Name}'.")
+        };
+
+        return $"delegate* unmanaged[{callingConvention}] <{parameterTypesAndReturnTypeString}>";
     }
 
     private static string GenerateCodeParameters(