- scriptified Heretic's blaster.

- scriptified all Effect functions of Fastprojectile's children
- implemented access to class meta data.
- added a VM instruction to retrieve the class metadata, to eliminate the overhead of the function call that would otherwise be needed.
- made GetClass() a builtin so that it can use the new instruction

Important note about this commit: Scriptifying CFlameMissile::Effect revealed a problem with the virtual function interface: In order to work, this needs to be explicitly enabled for each single native class that may be used as a base for a scripted class. Needless to say, this will end up way too much work, as there are over 100 native classes, excluding those which will be scriptified. But in order to fix the problem this partially broken state needs to be committed first.

src/scripting/codegeneration/codegen.cpp

@@ -5637,12 +5637,6 @@ FxExpression *FxIdentifier::ResolveMember(FCompileContext &ctx, PStruct *classct
 				return nullptr;
 			}
 
-			if (vsym->Flags & VARF_Static)
-			{
-				// todo. For now these cannot be defined so let's just exit.
-				ScriptPosition.Message(MSG_ERROR, "Static members not implemented yet.");
-				return nullptr;
-			}
 			auto x = isclass ? new FxClassMember(object, vsym, ScriptPosition) : new FxStructMember(object, vsym, ScriptPosition);
 			object = nullptr;
 			return x->Resolve(ctx);
@@ -5918,40 +5912,14 @@ FxExpression *FxClassDefaults::Resolve(FCompileContext& ctx)
 //
 //==========================================================================
 
-int BuiltinGetDefault(VMFrameStack *stack, VMValue *param, TArray<VMValue> &defaultparam, int numparam, VMReturn *ret, int numret)
-{
-	assert(numparam == 1);
-	PARAM_POINTER_AT(0, obj, DObject);
-	ACTION_RETURN_OBJECT(obj->GetClass()->Defaults);
-}
-
-//==========================================================================
-//
-//
-//
-//==========================================================================
-
 ExpEmit FxClassDefaults::Emit(VMFunctionBuilder *build)
 {
-	EmitParameter(build, obj, ScriptPosition);
-	PSymbol *sym = FindBuiltinFunction(NAME_BuiltinGetDefault, BuiltinGetDefault);
-
-	assert(sym->IsKindOf(RUNTIME_CLASS(PSymbolVMFunction)));
-	assert(((PSymbolVMFunction *)sym)->Function != nullptr);
-	auto callfunc = ((PSymbolVMFunction *)sym)->Function;
-	int opcode = (EmitTail ? OP_TAIL_K : OP_CALL_K);
-	build->Emit(opcode, build->GetConstantAddress(callfunc, ATAG_OBJECT), 1, 1);
-
-	if (EmitTail)
-	{
-		ExpEmit call;
-		call.Final = true;
-		return call;
-	}
-
-	ExpEmit out(build, REGT_POINTER);
-	build->Emit(OP_RESULT, 0, REGT_POINTER, out.RegNum);
-	return out;
+	ExpEmit ob = obj->Emit(build);
+	ob.Free(build);
+	ExpEmit meta(build, REGT_POINTER);
+	build->Emit(OP_META, meta.RegNum, ob.RegNum);
+	build->Emit(OP_LO, meta.RegNum, meta.RegNum, build->GetConstantInt(myoffsetof(PClass, Defaults)));
+	return meta;
 
 }
 
@@ -6272,6 +6240,11 @@ FxStructMember::~FxStructMember()
 
 bool FxStructMember::RequestAddress(FCompileContext &ctx, bool *writable)
 {
+	// Cannot take the address of metadata variables.
+	if (membervar->Flags & VARF_Static)
+	{
+		return false;
+	}
 	AddressRequested = true;
 	if (writable != nullptr) *writable = (AddressWritable && !ctx.CheckReadOnly(membervar->Flags) &&
 											(!classx->ValueType->IsKindOf(RUNTIME_CLASS(PPointer)) || !static_cast<PPointer*>(classx->ValueType)->IsConst));
@@ -6411,6 +6384,14 @@ ExpEmit FxStructMember::Emit(VMFunctionBuilder *build)
 		obj = newobj;
 	}
 
+	if (membervar->Flags & VARF_Static)
+	{
+		obj.Free(build);
+		ExpEmit meta(build, REGT_POINTER);
+		build->Emit(OP_META, meta.RegNum, obj.RegNum);
+		obj = meta;
+	}
+
 	if (AddressRequested)
 	{
 		if (membervar->Offset == 0)
@@ -6953,6 +6934,13 @@ FxExpression *FxFunctionCall::Resolve(FCompileContext& ctx)
 		}
 		break;
 
+	case NAME_GetClass:
+		if (CheckArgSize(NAME_GetClass, ArgList, 0, 0, ScriptPosition))
+		{
+			func = new FxGetClass(new FxSelf(ScriptPosition));
+		}
+		break;
+
 	case NAME_Random:
 		// allow calling Random without arguments to default to (0, 255)
 		if (ArgList.Size() == 0)
@@ -7132,6 +7120,12 @@ FxExpression *FxMemberFunctionCall::Resolve(FCompileContext& ctx)
 		// handle builtins: Vectors got 2: Length and Unit.
 		if (MethodName == NAME_Length || MethodName == NAME_Unit)
 		{
+			if (ArgList.Size() > 0)
+			{
+				ScriptPosition.Message(MSG_ERROR, "too many parameters in call to %s", MethodName.GetChars());
+				delete this;
+				return nullptr;
+			}
 			auto x = new FxVectorBuiltin(Self, MethodName);
 			Self = nullptr;
 			delete this;
@@ -7144,6 +7138,17 @@ FxExpression *FxMemberFunctionCall::Resolve(FCompileContext& ctx)
 		auto ptype = static_cast<PPointer *>(Self->ValueType)->PointedType;
 		if (ptype->IsKindOf(RUNTIME_CLASS(PStruct)))
 		{
+			if (ptype->IsKindOf(RUNTIME_CLASS(PClass)) && MethodName == NAME_GetClass)
+			{
+				if (ArgList.Size() > 0)
+				{
+					ScriptPosition.Message(MSG_ERROR, "too many parameters in call to %s", MethodName.GetChars());
+					delete this;
+					return nullptr;
+				}
+				auto x = new FxGetClass(Self);
+				return x->Resolve(ctx);
+			}
 			cls = static_cast<PStruct *>(ptype);
 		}
 		else
@@ -7976,6 +7981,44 @@ ExpEmit FxVectorBuiltin::Emit(VMFunctionBuilder *build)
 	return to;
 }
 
+//==========================================================================
+//
+//
+//==========================================================================
+
+FxGetClass::FxGetClass(FxExpression *self)
+	:FxExpression(EFX_GetClass, self->ScriptPosition)
+{
+	Self = self;
+}
+
+FxGetClass::~FxGetClass()
+{
+	SAFE_DELETE(Self);
+}
+
+FxExpression *FxGetClass::Resolve(FCompileContext &ctx)
+{
+	SAFE_RESOLVE(Self, ctx);
+	if (!Self->IsObject())
+	{
+		ScriptPosition.Message(MSG_ERROR, "GetClass() requires an object");
+		delete this;
+		return nullptr;
+	}
+	ValueType = NewClassPointer(static_cast<PClass*>(static_cast<PPointer*>(Self->ValueType)->PointedType));
+	return this;
+}
+
+ExpEmit FxGetClass::Emit(VMFunctionBuilder *build)
+{
+	ExpEmit op = Self->Emit(build);
+	op.Free(build);
+	ExpEmit to(build, REGT_POINTER);
+	build->Emit(OP_META, to.RegNum, op.RegNum);
+	return to;
+}
+
 //==========================================================================
 //
 // FxSequence :: Resolve