(#72) LocalDeclarationInfo: extract the function parameter informatio…

…n into FunctionType

Cesium.CodeGen.Tests/CodeGenTypeTests.cs

@@ -82,4 +82,12 @@ public Task ArrayDeclaration() => DoTest(@"int main()
     int x[1];
     return 0;
 }");
+
+    [Fact]
+    public Task StructFunctionMemberDeclaration() => DoTest(@"typedef struct { void bar(int unused); } foo;
+int main(void) {}");
+
+    [Fact]
+    public Task BasicTypeDef() => DoTest(@"typedef int foo;
+int main(void) { foo x; }");
 }

Cesium.CodeGen/Contexts/TranslationUnitContext.cs

@@ -22,8 +22,7 @@ internal void GenerateType(IGeneratedType type, string name)
         _types.Add(name, typeReference);
     }
 
-    // TODO[#72]: Unnecessary.
-    internal void AddType(TypeReference type, string name) => _types.Add(name, type);
+    internal void AddPlainType(IType type, string name) => _types.Add(name, type.Resolve(this));
 
     internal TypeReference? GetTypeReference(IGeneratedType type) => _generatedTypes.GetValueOrDefault(type);
     internal TypeReference? GetTypeReference(string typeName) => _types.GetValueOrDefault(typeName);

Cesium.CodeGen/Ir/BlockItems/DeclarationBlockItem.cs

@@ -63,17 +63,13 @@ private static void EmitScopedIdentifier(IDeclarationScope scope, ScopedIdentifi
         foreach (var (declaration, initializer) in declarations)
         {
             var method = scope.Method;
-            var (type, identifier, parametersInfo, cliImportMemberName) = declaration;
+            var (type, identifier, cliImportMemberName) = declaration;
 
             // TODO[#91]: A place to register whether {type} is const or not.
 
             if (identifier == null)
                 throw new NotSupportedException("An anonymous local declaration isn't supported.");
 
-            if (parametersInfo != null)
-                throw new NotImplementedException(
-                    $"A local declaration of function {identifier} isn't supported, yet.");
-
             if (cliImportMemberName != null)
                 throw new NotSupportedException(
                     $"Local declaration with a CLI import member name {cliImportMemberName} isn't supported.");

Cesium.CodeGen/Ir/Declarations/LocalDeclarationInfo.cs

@@ -12,14 +12,13 @@ namespace Cesium.CodeGen.Ir.Declarations;
 internal record LocalDeclarationInfo(
     IType Type,
     string? Identifier,
-    ParametersInfo? Parameters,
     string? CliImportMemberName)
 {
     public static LocalDeclarationInfo Of(IReadOnlyList<IDeclarationSpecifier> specifiers, Declarator? declarator)
     {
         var (type, cliImportMemberName) = ProcessSpecifiers(specifiers);
         if (declarator == null)
-            return new LocalDeclarationInfo(type, null, null, null);
+            return new LocalDeclarationInfo(type, null, null);
 
         var (pointer, directDeclarator) = declarator;
         if (pointer != null)
@@ -32,7 +31,6 @@ public static LocalDeclarationInfo Of(IReadOnlyList<IDeclarationSpecifier> speci
         }
 
         string? identifier = null;
-        ParametersInfo? parameters = null;
 
         var currentDirectDeclarator = directDeclarator;
         while (currentDirectDeclarator != null)
@@ -46,6 +44,11 @@ public static LocalDeclarationInfo Of(IReadOnlyList<IDeclarationSpecifier> speci
                         throw new NotImplementedException(
                             "Non-empty identifier list inside of a direct declarator is not supported, yet:" +
                             $" {string.Join(", ", identifiers)}");
+
+                    // An empty identifier list is `()` in a declaration like `int main()`. It means that there's an
+                    // empty parameter list, actually.
+                    type = ProcessFunctionParameters(type, null);
+
                     break;
                 }
 
@@ -57,11 +60,8 @@ public static LocalDeclarationInfo Of(IReadOnlyList<IDeclarationSpecifier> speci
                     break;
 
                 case ParameterListDirectDeclarator parametersD:
-                    if (parameters != null)
-                        throw new NotSupportedException(
-                            $"Second parameters list declarator for an entity already having one: {parametersD}.");
-
-                    parameters = ParametersInfo.Of(parametersD.Parameters);
+                    var (_ /* base */, parameters) = parametersD;
+                    type = ProcessFunctionParameters(type, parameters);
                     break;
 
                 case ArrayDirectDeclarator array:
@@ -112,7 +112,7 @@ public static LocalDeclarationInfo Of(IReadOnlyList<IDeclarationSpecifier> speci
             currentDirectDeclarator = currentDirectDeclarator.Base;
         }
 
-        return new LocalDeclarationInfo(type, identifier, parameters, cliImportMemberName);
+        return new LocalDeclarationInfo(type, identifier, cliImportMemberName);
     }
 
     private static (IType, string? cliImportMemberName) ProcessSpecifiers(
@@ -281,4 +281,7 @@ private static IType ProcessSimpleTypeSpecifiers(
                     $"Simple type specifiers are not supported: {string.Join(" ", typeNames)}"),
             });
     }
+
+    private static IType ProcessFunctionParameters(IType returnType, ParameterTypeList? parameters) =>
+        new FunctionType(ParametersInfo.Of(parameters), returnType);
 }

Cesium.CodeGen/Ir/ParametersInfo.cs

@@ -6,8 +6,9 @@ namespace Cesium.CodeGen.Ir;
 
 internal record ParametersInfo(IList<ParameterInfo> Parameters, bool IsVoid, bool IsVarArg)
 {
-    public static ParametersInfo Of(ParameterTypeList parameters)
+    public static ParametersInfo? Of(ParameterTypeList? parameters)
     {
+        if (parameters == null) return null;
         var (parameterList, hasEllipsis) = parameters;
 
         bool isVoid;
@@ -46,10 +47,7 @@ public static ParameterInfo Of(ParameterDeclaration declaration)
             throw new NotImplementedException(
                 $"Parameter with abstract declarator is not supported, yet: {declaration}.");
 
-        var (type, identifier, parameters, cliImportMemberName) = LocalDeclarationInfo.Of(specifiers, declarator);
-
-        if (parameters != null)
-            throw new NotImplementedException($"Parameters with parameters are not supported, yet: {parameters}.");
+        var (type, identifier, cliImportMemberName) = LocalDeclarationInfo.Of(specifiers, declarator);
 
         if (cliImportMemberName != null)
             throw new NotSupportedException("CLI import specifier isn't supported for a parameter.");

Cesium.CodeGen/Ir/TopLevel/FunctionDefinition.cs

@@ -16,19 +16,18 @@ internal class FunctionDefinition : ITopLevelNode
 {
     private const string MainFunctionName = "main";
 
-    private readonly IType _returnType;
+    private readonly FunctionType _functionType;
     private readonly string _name;
-    private readonly ParametersInfo? _parameters;
     private readonly CompoundStatement _statement;
 
     private bool IsMain => _name == MainFunctionName;
 
-
     public FunctionDefinition(Ast.FunctionDefinition function)
     {
         var (specifiers, declarator, declarations, astStatement) = function;
-        (_returnType, var name, _parameters, var cliImportMemberName) =
-            LocalDeclarationInfo.Of(specifiers, declarator);
+        var (type, name, cliImportMemberName) = LocalDeclarationInfo.Of(specifiers, declarator);
+        _functionType = type as FunctionType
+                        ?? throw new NotSupportedException($"Function of not a function type: {type}.");
         _name = name ?? throw new NotSupportedException($"Function without name: {function}.");
 
         if (declarations?.IsEmpty == false)
@@ -42,21 +41,22 @@ public FunctionDefinition(Ast.FunctionDefinition function)
 
     public void EmitTo(TranslationUnitContext context)
     {
-        var returnType = _returnType.Resolve(context);
-        if (IsMain && returnType != context.TypeSystem.Int32)
+        var (parameters, returnType) = _functionType;
+        var resolvedReturnType = returnType.Resolve(context);
+        if (IsMain && resolvedReturnType != context.TypeSystem.Int32)
             throw new NotSupportedException(
                 $"Invalid return type for the {_name} function: " +
-                $"int expected, got {_returnType}.");
+                $"int expected, got {returnType}.");
 
-        if (IsMain && _parameters?.IsVarArg == true)
+        if (IsMain && parameters?.IsVarArg == true)
             throw new NotSupportedException($"Variable arguments for the {_name} function aren't supported.");
 
         var declaration = context.Functions.GetValueOrDefault(_name);
-        declaration?.VerifySignatureEquality(_name, _parameters, _returnType);
+        declaration?.VerifySignatureEquality(_name, parameters, returnType);
 
         var method = declaration switch
         {
-            null => context.ModuleType.DefineMethod(context, _name, returnType, _parameters),
+            null => context.ModuleType.DefineMethod(context, _name, resolvedReturnType, parameters),
             { MethodReference: MethodDefinition md } => md,
             _ => throw new NotSupportedException($"Function {_name} already defined as immutable.")
         };
@@ -65,7 +65,7 @@ public void EmitTo(TranslationUnitContext context)
             throw new NotSupportedException($"Double definition of function {_name}.");
 
         if (declaration == null)
-            context.Functions.Add(_name, new FunctionInfo(_parameters, _returnType, method, IsDefined: true));
+            context.Functions.Add(_name, new FunctionInfo(parameters, returnType, method, IsDefined: true));
         else
             context.Functions[_name] = declaration with { IsDefined = true };
 
@@ -91,10 +91,10 @@ public void EmitTo(TranslationUnitContext context)
     /// <returns>Whether the synthetic entry point should be generated.</returns>
     private bool ValidateMainParameters()
     {
-        if (_parameters == null)
+        if (_functionType.Parameters == null)
             return false; // TODO[#87]: Decide whether this is normal or not.
 
-        var (parameterList, isVoid, isVarArg) = _parameters;
+        var (parameterList, isVoid, isVarArg) = _functionType.Parameters;
         if (isVoid) return false; // supported, no synthetic entry point required
 
         if (isVarArg)
@@ -264,7 +264,7 @@ private void EmitCode(TranslationUnitContext context, FunctionScope scope)
                 instructions.Add(Instruction.Create(OpCodes.Ldc_I4_0));
                 instructions.Add(Instruction.Create(OpCodes.Ret));
             }
-            else if (_returnType.Resolve(context) == context.TypeSystem.Void)
+            else if (_functionType.ReturnType.Resolve(context) == context.TypeSystem.Void)
             {
                 var instructions = scope.Method.Body.Instructions;
                 instructions.Add(Instruction.Create(OpCodes.Ret));

Cesium.CodeGen/Ir/TopLevel/TopLevelDeclaration.cs

@@ -39,7 +39,7 @@ private static void EmitScopedIdentifier(
 
         foreach (var (declaration, initializer) in items)
         {
-            var (type, identifier, parametersInfo, cliImportMemberName) = declaration;
+            var (type, identifier, cliImportMemberName) = declaration;
             if (identifier == null)
                 throw new NotSupportedException($"Unnamed global symbol of type {type} is not supported.");
 
@@ -49,17 +49,20 @@ private static void EmitScopedIdentifier(
                     throw new NotSupportedException(
                         $"Initializer expression for a CLI import isn't supported: {initializer}.");
 
-                EmitCliImportDeclaration(context, identifier, parametersInfo, type, cliImportMemberName);
+                if (type is not FunctionType cliFunction)
+                    throw new NotSupportedException($"CLI initializer should be a function for identifier {identifier}.");
+
+                EmitCliImportDeclaration(context, identifier, cliFunction, cliImportMemberName);
                 continue;
             }
 
-            if (parametersInfo != null)
+            if (type is FunctionType functionType)
             {
                 if (initializer != null)
                     throw new NotSupportedException(
                         $"Initializer expression for a function declaration isn't supported: {initializer}.");
 
-                EmitFunctionDeclaration(context, identifier, parametersInfo, type);
+                EmitFunctionDeclaration(context, identifier, functionType);
                 continue;
             }
 
@@ -78,23 +81,23 @@ private static void EmitScopedIdentifier(
     private static void EmitCliImportDeclaration(
         TranslationUnitContext context,
         string name,
-        ParametersInfo? parametersInfo,
-        IType returnType,
+        FunctionType functionType,
         string memberName)
     {
         var method = context.MethodLookup(memberName);
         if (method == null) throw new NotSupportedException($"Cannot find CLI-imported member {memberName}.");
 
-        // TODO[#93]: Verify method signature: {parametersIInfo, type}.
+        var (parametersInfo, returnType) = functionType;
+        // TODO[#93]: Verify method signature: {parametersInfo, type}.
         context.Functions.Add(name, new FunctionInfo(parametersInfo, returnType, method, IsDefined: true));
     }
 
     private static void EmitFunctionDeclaration(
         TranslationUnitContext context,
         string identifier,
-        ParametersInfo parametersInfo,
-        IType returnType)
+        FunctionType functionType)
     {
+        var (parametersInfo, returnType) = functionType;
         var existingFunction = context.Functions.GetValueOrDefault(identifier);
         if (existingFunction != null)
         {
@@ -118,34 +121,17 @@ private static void EmitTypeDef(TranslationUnitContext context, TypeDefDeclarati
         declaration.Deconstruct(out var types);
         foreach (var typeDef in types)
         {
-            var (type, identifier, parametersInfo, cliImportMemberName) = typeDef;
+            var (type, identifier, cliImportMemberName) = typeDef;
             if (identifier == null)
                 throw new NotSupportedException($"Anonymous typedef not supported: {type}.");
 
-            if (parametersInfo != null)
-                GenerateFunctionType(context, identifier, parametersInfo, type);
-
             if (cliImportMemberName != null)
                 throw new NotSupportedException($"typedef for CLI import not supported: {cliImportMemberName}.");
 
             if (type is IGeneratedType t)
                 context.GenerateType(t, identifier);
             else
-                throw new NotSupportedException($"Not supported type generation for type {type}.");
+               context.AddPlainType(type, identifier);
         }
     }
-
-    private static void GenerateFunctionType(
-        TranslationUnitContext context,
-        string identifier,
-        ParametersInfo parametersInfo,
-        IType returnType)
-    {
-        var type = new FunctionPointerType();
-
-        throw new NotImplementedException(
-            $"Function type not supported, yet: {identifier}: {parametersInfo} → {returnType}");
-
-        context.AddType(type, identifier);
-    }
 }

Cesium.CodeGen/Ir/Types/FunctionType.cs

@@ -0,0 +1,12 @@
+using Cesium.CodeGen.Contexts;
+using Mono.Cecil;
+
+namespace Cesium.CodeGen.Ir.Types;
+
+internal record FunctionType(ParametersInfo? Parameters, IType ReturnType) : IType
+{
+    public TypeReference Resolve(TranslationUnitContext context) =>
+        throw new NotImplementedException();
+
+    public int SizeInBytes => throw new NotImplementedException("Could not calculate size yet.");
+}

Cesium.CodeGen/Ir/Types/IType.cs

@@ -3,8 +3,19 @@
 
 namespace Cesium.CodeGen.Ir.Types;
 
+/// <summary>An interface representing a C type.</summary>
+/// <remarks>
+/// Can be of two flavors: an <see cref="IGeneratedType"/> or a plain type that doesn't require any byte code to be
+/// generated (a basic type, a pointer or a function pointer.
+/// </remarks>
 internal interface IType
 {
     TypeReference Resolve(TranslationUnitContext context);
     int SizeInBytes { get; }
 }
+
+/// <summary>A generated type, i.e. a type that has some bytecode to be generated once.</summary>
+internal interface IGeneratedType : IType
+{
+    TypeDefinition Emit(string name, TranslationUnitContext context);
+}

Cesium.CodeGen/Ir/Types/StructType.cs

@@ -23,15 +23,11 @@ public TypeDefinition Emit(string name, TranslationUnitContext context)
 
         foreach (var member in _members)
         {
-            var (type, identifier, parametersInfo, cliImportMemberName) = member;
+            var (type, identifier, cliImportMemberName) = member;
             if (identifier == null)
                 throw new NotImplementedException(
                     $"Anonymous struct members for {name} aren't supported, yet: {type}.");
 
-            if (parametersInfo != null)
-                throw new NotImplementedException(
-                    $"Functional struct members for {name} aren't supported, yet: {identifier}.");
-
             if (cliImportMemberName != null)
                 throw new NotSupportedException(
                     $"CLI imports inside struct members aren't supported: {cliImportMemberName}.");