(#72) CodeGen: support fixed arrays inside of structs

Cesium.CodeGen.Tests/CodeGenTestBase.cs

@@ -105,9 +105,12 @@ private static void DumpTypes(IEnumerable<TypeDefinition> types, StringBuilder r
             if (type.ClassSize != -1)
                 result.AppendLine($"{Indent(indent)}Size: {type.ClassSize}");
 
+            if (type.HasCustomAttributes)
+                PrintCustomAttributes(indent, type.CustomAttributes);
+
             if (type.HasNestedTypes)
             {
-                result.AppendLine($"{Indent(indent)}Types:");
+                result.AppendLine($"{Indent(indent)}Nested types:");
                 DumpTypes(type.NestedTypes, result, indent + 1);
             }
 
@@ -117,8 +120,12 @@ private static void DumpTypes(IEnumerable<TypeDefinition> types, StringBuilder r
                 foreach (var field in type.Fields)
                 {
                     result.AppendLine($"{Indent(indent + 1)}{field}");
+
+                    if (field.HasCustomAttributes)
+                        PrintCustomAttributes(indent + 1, field.CustomAttributes);
+
                     var initialValue = field.InitialValue;
-                    if (initialValue != null)
+                    if (initialValue.Length > 0)
                     {
                         if (type.Name == AssemblyContext.ConstantPoolTypeName)
                         {
@@ -143,6 +150,18 @@ private static void DumpTypes(IEnumerable<TypeDefinition> types, StringBuilder r
                 DumpMethods(type, result, 2);
             }
         }
+
+        void PrintCustomAttributes(int nestedIndent, IEnumerable<CustomAttribute> customAttributes)
+        {
+            result.AppendLine($"{Indent(nestedIndent)}Custom attributes:");
+            foreach (var customAttribute in customAttributes)
+            {
+                var arguments = string.Join(", ", customAttribute.ConstructorArguments.Select(a => a.Value));
+                result.AppendLine($"{Indent(nestedIndent)}- {customAttribute.AttributeType.Name}({arguments})");
+            }
+
+            result.AppendLine();
+        }
     }
 
     private static string Indent(int n = 1) => new(' ', n * 2);

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.ConstCharLiteralDeduplication.verified.txt

@@ -16,7 +16,7 @@
       IL_0016: ret
 
   Type: <ConstantPool>
-  Types:
+  Nested types:
     Type: <ConstantPool>/<ConstantPoolItemType7>
     Pack: 1
     Size: 7

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.ConstCharLiteralTest.verified.txt

@@ -10,7 +10,7 @@
       IL_0008: ret
 
   Type: <ConstantPool>
-  Types:
+  Nested types:
     Type: <ConstantPool>/<ConstantPoolItemType7>
     Pack: 1
     Size: 7

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.GlobalVariableModuleTest.verified.txt

@@ -2,7 +2,6 @@
   Type: <Module>
   Fields:
     System.Int32 <Module>::x
-       Init with: []
   Methods:
     System.Void <Module>::.cctor()
       IL_0000: ldc.i4.s 50

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.GlobalVariableTest.verified.txt

@@ -4,7 +4,6 @@
   Type: TestClass
   Fields:
     System.Int32 TestClass::x
-       Init with: []
   Methods:
     System.Void TestClass::.cctor()
       IL_0000: ldc.i4.s 50

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.SingleFieldStructDefinition.verified.txt

@@ -4,4 +4,3 @@
   Type: foo
   Fields:
     System.Int32 foo::x
-       Init with: []

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.StructAddressWithPointerMemberAccessGet.verified.txt

@@ -12,4 +12,3 @@
   Type: foo
   Fields:
     System.Int32 foo::x
-       Init with: []

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.StructAddressWithPointerMemberAccessSet.verified.txt

@@ -14,4 +14,3 @@
   Type: foo
   Fields:
     System.Int32 foo::x
-       Init with: []

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.StructFunctionMemberDeclaration.verified.txt

@@ -8,4 +8,3 @@
   Type: foo
   Fields:
     method System.Void *(System.Int32) foo::bar
-       Init with: []

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.StructUsageWithMemberAccessGet.verified.txt

@@ -12,4 +12,3 @@
   Type: foo
   Fields:
     System.Int32 foo::x
-       Init with: []

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.StructUsageWithMemberAccessSet.verified.txt

@@ -14,4 +14,3 @@
   Type: foo
   Fields:
     System.Int32 foo::x
-       Init with: []

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.StructUsageWithPointerMemberAccessGet.verified.txt

@@ -11,4 +11,3 @@
   Type: foo
   Fields:
     System.Int32 foo::x
-       Init with: []

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.StructUsageWithPointerMemberAccessSet.verified.txt

@@ -13,4 +13,3 @@
   Type: foo
   Fields:
     System.Int32 foo::x
-       Init with: []

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.StructWithArray.verified.txt

@@ -0,0 +1,19 @@
+Module: Primary
+  Type: <Module>
+
+  Type: foo
+  Nested types:
+    Type: foo/<SyntheticBuffer>x
+    Pack: 0
+    Size: 16
+    Custom attributes:
+    - CompilerGeneratedAttribute()
+    - UnsafeValueTypeAttribute()
+
+    Fields:
+      System.Int32 foo/<SyntheticBuffer>x::FixedElementField
+  Fields:
+    foo/<SyntheticBuffer>x foo::x
+    Custom attributes:
+    - FixedBufferAttribute(System.Int32, 16)
+

Cesium.CodeGen.Tests/verified/CodeGenTypeTests.TypeDefStructUsage.verified.txt

@@ -10,4 +10,3 @@
   Type: foo
   Fields:
     System.Int32 foo::x
-       Init with: []

Cesium.CodeGen/Ir/Types/IType.cs

@@ -11,6 +11,10 @@ namespace Cesium.CodeGen.Ir.Types;
 internal interface IType
 {
     TypeReference Resolve(TranslationUnitContext context);
+
+    FieldDefinition CreateFieldOfType(TranslationUnitContext context, TypeDefinition ownerType, string fieldName) =>
+        new(fieldName, FieldAttributes.Public, Resolve(context));
+
     int SizeInBytes { get; }
 }
 

Cesium.CodeGen/Ir/Types/InPlaceArrayType.cs

@@ -1,3 +1,4 @@
+using System.Runtime.CompilerServices;
 using Cesium.CodeGen.Contexts;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
@@ -12,6 +13,35 @@ public TypeReference Resolve(TranslationUnitContext context)
         return Base.Resolve(context).MakePointerType();
     }
 
+    public FieldDefinition CreateFieldOfType(TranslationUnitContext context, TypeDefinition ownerType, string fieldName)
+    {
+        var itemType = Base.Resolve(context);
+        var bufferType = CreateFixedBufferType(context.Module, itemType, fieldName);
+        ownerType.NestedTypes.Add(bufferType);
+
+        return new FieldDefinition(fieldName, FieldAttributes.Public, bufferType)
+        {
+            CustomAttributes = { GenerateCustomFieldAttribute() }
+        };
+
+        CustomAttribute GenerateCustomFieldAttribute()
+        {
+            var fixedBufferCtor = typeof(FixedBufferAttribute).GetConstructor(new[] { typeof(Type), typeof(int) });
+            if (fixedBufferCtor == null)
+                throw new NotSupportedException(
+                    "Cannot find a constructor with signature (Type, Int32) in type FixedBufferAttribute.");
+
+            return new CustomAttribute(context.Module.ImportReference(fixedBufferCtor))
+            {
+                ConstructorArguments =
+                {
+                    new CustomAttributeArgument(context.Module.ImportReference(typeof(Type)), itemType),
+                    new CustomAttributeArgument(context.TypeSystem.Int32, SizeInBytes)
+                }
+            };
+        }
+    }
+
     public void EmitInitializer(IDeclarationScope scope)
     {
         if (Base is not PrimitiveType)
@@ -26,4 +56,38 @@ public void EmitInitializer(IDeclarationScope scope)
     }
 
     public int SizeInBytes => Base.SizeInBytes * Size;
+
+    private TypeDefinition CreateFixedBufferType(
+        ModuleDefinition module,
+        TypeReference fieldType,
+        string fieldName)
+    {
+        // An example of what C# does for fixed int x[20]:
+        //
+        // [StructLayout(LayoutKind.Sequential, Size = 80)]
+        // [CompilerGenerated]
+        // [UnsafeValueType]
+        // public struct <x>e__FixedBuffer
+        // {
+        //     public int FixedElementField;
+        // }
+
+        var compilerGeneratedCtor = typeof(CompilerGeneratedAttribute).GetConstructor(Array.Empty<Type>());
+        var compilerGeneratedAttribute = new CustomAttribute(module.ImportReference(compilerGeneratedCtor));
+
+        var unsafeValueTypeCtor = typeof(UnsafeValueTypeAttribute).GetConstructor(Array.Empty<Type>());
+        var unsafeValueTypeAttribute = new CustomAttribute(module.ImportReference(unsafeValueTypeCtor));
+
+        return new TypeDefinition(
+            "",
+            $"<SyntheticBuffer>{fieldName}",
+            TypeAttributes.Public | TypeAttributes.Sealed | TypeAttributes.SequentialLayout | TypeAttributes.NestedPublic,
+            module.ImportReference(typeof(ValueType)))
+        {
+            PackingSize = 0,
+            ClassSize = SizeInBytes,
+            CustomAttributes = { compilerGeneratedAttribute, unsafeValueTypeAttribute },
+            Fields = { new FieldDefinition("FixedElementField", FieldAttributes.Public, fieldType) }
+        };
+    }
 }

Cesium.CodeGen/Ir/Types/StructType.cs

@@ -32,11 +32,8 @@ public TypeDefinition Emit(string name, TranslationUnitContext context)
                 throw new NotSupportedException(
                     $"CLI imports inside struct members aren't supported: {cliImportMemberName}.");
 
-            structType.Fields.Add(
-                new FieldDefinition(
-                    identifier,
-                    FieldAttributes.Public,
-                    type.Resolve(context)));
+            var field = type.CreateFieldOfType(context, structType, identifier);
+            structType.Fields.Add(field);
         }
 
         return structType;

Cesium.IntegrationTests/struct.c

@@ -0,0 +1,10 @@
+typedef struct
+{
+    int x[4];
+} foo;
+
+int main()
+{
+    foo x;
+    return 42;
+}