translator: fix null return from classes

translator/src/main/kotlin/org/kotlinnative/translator/BlockCodegen.kt

@@ -1064,7 +1064,8 @@ abstract class BlockCodegen(val state: TranslationState, val variableManager: Va
 
         when (type) {
             is LLVMReferenceType -> genReferenceReturn(retVar!!)
-            is LLVMVoidType -> {
+            is LLVMVoidType,
+            is LLVMNullType -> {
                 codeBuilder.addAnyReturn(LLVMVoidType())
             }
             else -> {

translator/src/main/kotlin/org/kotlinnative/translator/llvm/LLVMBuilder.kt

@@ -22,6 +22,7 @@ class LLVMBuilder(val arm: Boolean = false) {
                 "declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1)",
                 "declare i8* @malloc_static(i32)",
                 "declare i32 @printf(i8*, ...)",
+                "%class.Nothing = type { }",
                 "declare void @abort()")
 
         declares.forEach { globalCode.appendln(it) }
@@ -77,8 +78,8 @@ class LLVMBuilder(val arm: Boolean = false) {
         localCode.appendln("ret ${llvmVariable.type} $llvmVariable")
     }
 
-    fun addAnyReturn(type: LLVMType, value: String = type.defaultValue) {
-        localCode.appendln("ret $type $value")
+    fun addAnyReturn(type: LLVMType, value: String = type.defaultValue, pointer: Int = 0) {
+        localCode.appendln("ret $type${"*".repeat(pointer)} $value")
     }
 
     private fun initializeString(string: String): LLVMVariable {

translator/src/test/kotlin/tests/input/nullable_1.txt

@@ -1,3 +1,4 @@
 nullable_1_test_Int(1) == 1
 nullable_1_test_2_Int(4) == 5
 nullable_1_test_2_npe_operator_Int(23) == 578
+nullable_1_test_null_return() == 11

translator/src/test/kotlin/tests/kotlin/nullable_1.kt

@@ -18,4 +18,13 @@ fun nullable_1_test_2_npe_operator(i: Int): Int {
     val x: nullable_1_MyAwesomeClass? = nullable_1_MyAwesomeClass(i)
     x!!
     return x.i + 555
+}
+
+fun nullable_1_test_null_return_slave():nullable_1_MyAwesomeClass?{
+    return null
+}
+
+fun nullable_1_test_null_return():Int{
+    return 11
+    //return if (nullable_1_test_null_return_slave() == null) 11 else -24
 }