[KT-33525] Allow null literal in variadic arguments (#3312)

[KT-33525] Allow null literal in variadic arguments

Pass null as CTypes.voidPtr

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/cgen/CBridgeGen.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.backend.konan.PrimitiveBinaryType
 import org.jetbrains.kotlin.backend.konan.RuntimeNames
 import org.jetbrains.kotlin.backend.konan.ir.*
 import org.jetbrains.kotlin.backend.konan.isObjCMetaClass
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.builtins.UnsignedType
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
@@ -751,6 +752,9 @@ private fun KotlinStubs.mapBlockType(
 private fun KotlinStubs.mapType(type: IrType, retained: Boolean, variadic: Boolean, location: TypeLocation): ValuePassing =
         mapType(type, retained, variadic, location, { reportUnsupportedType(it, type, location) })
 
+private fun IrType.isTypeOfNullLiteral(): Boolean = this is IrSimpleType && hasQuestionMark
+        && classifier.isClassWithFqName(KotlinBuiltIns.FQ_NAMES.nothing)
+
 private fun KotlinStubs.mapType(
         type: IrType,
         retained: Boolean,
@@ -770,6 +774,7 @@ private fun KotlinStubs.mapType(
     type.isFloat() -> TrivialValuePassing(irBuiltIns.floatType, CTypes.float)
     type.isDouble() -> TrivialValuePassing(irBuiltIns.doubleType, CTypes.double)
     type.classifierOrNull == symbols.interopCPointer -> TrivialValuePassing(type, CTypes.voidPtr)
+    type.isTypeOfNullLiteral() && variadic  -> TrivialValuePassing(symbols.interopCPointer.typeWithStarProjections.makeNullable(), CTypes.voidPtr)
     type.isUByte() -> UnsignedValuePassing(type, CTypes.signedChar, CTypes.unsignedChar)
     type.isUShort() -> UnsignedValuePassing(type, CTypes.short, CTypes.unsignedShort)
     type.isUInt() -> UnsignedValuePassing(type, CTypes.int, CTypes.unsignedInt)

backend.native/tests/interop/basics/callbacksAndVarargs.kt

@@ -31,7 +31,8 @@ fun main(args: Array<String>) {
             111u,
             ULong.MAX_VALUE,
             E.TWO,
-            cValue<S> { x = 15 }
+            cValue<S> { x = 15 },
+            null
     ).useContents {
         assertEquals(1, a1)
         assertEquals(2.toByte(), a2)
@@ -47,5 +48,6 @@ fun main(args: Array<String>) {
         assertEquals(ULong.MAX_VALUE, a12)
         assertEquals(E.TWO, a13)
         assertEquals(15, a14.x)
+        assertEquals(null, a15)
     }
 }

backend.native/tests/interop/basics/ccallbacksAndVarargs.def

@@ -43,6 +43,7 @@ struct Args {
     unsigned long long a12;
     enum E a13;
     struct S a14;
+    void* a15;
 };
 
 static struct Args getVarargs(int ignore, ...) {
@@ -63,7 +64,8 @@ static struct Args getVarargs(int ignore, ...) {
         va_arg(args, unsigned int),
         va_arg(args, unsigned long long),
         va_arg(args, enum E),
-        va_arg(args, struct S)
+        va_arg(args, struct S),
+        va_arg(args, void*)
     };
 
     va_end(args);