Char-based enum shall be mapped to integer-based (#3621)

* Char-based enum shall be mapped to integer-basede

* revised, using actual base type and Byte for constants of CharType

* minor cleanup

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/StubIrBuilder.kt

@@ -221,7 +221,11 @@ class StubsBuildingContextImpl(
         get() = stubIrContext.getKotlinName(this)
 
     override fun tryCreateIntegralStub(type: Type, value: Long): IntegralConstantStub? {
-        val integerType = type.unwrapTypedefs() as? IntegerType ?: return null
+        val integerType = when (val unwrappedType = type.unwrapTypedefs()) {
+            is IntegerType -> unwrappedType
+            CharType -> IntegerType(1, true, "char")
+            else -> return null
+        }
         val size = integerType.size
         if (size != 1 && size != 2 && size != 4 && size != 8) return null
         return IntegralConstantStub(value, size, declarationMapper.isMappedToSigned(integerType))
@@ -386,4 +390,4 @@ class StubIrBuilder(private val context: StubIrContext) {
     private fun generateStubsForObjCCategory(objCCategory: ObjCCategory) {
         addStubs(ObjCCategoryStubBuilder(buildingContext, objCCategory).build())
     }
-}
+}

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

@@ -71,6 +71,23 @@ enum NonStrictEnum2 {
     NonStrictEnum2B __attribute__((unused)) = 1
 };
 
+// KT-34025
+typedef char Char;
+enum EnumCharBase : Char {
+    EnumCharBaseA,
+    EnumCharBaseB
+};
+
+static int sendEnum(enum EnumCharBase x) {
+	return (int)x + 2;
+}
+
+enum EnumExplicitChar : char {
+	EnumExplicitCharA = 'a',
+	EnumExplicitCharB = 'b',
+	EnumExplicitCharDup = 'a'
+};
+
 typedef float __attribute__ ((__vector_size__ (16)))   KVector4f;
 typedef int   __attribute__ ((__vector_size__ (16)))   KVector4i32;
 

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

@@ -21,6 +21,11 @@ fun main() {
     assertEquals(1u, StrictEnum2.StrictEnum2B.value)
     assertEquals(0u, NonStrictEnum1A)
     assertEquals(1u, NonStrictEnum2B)
+    assertEquals(1, EnumCharBase.EnumCharBaseB.value)
+    assertEquals(3, sendEnum(EnumCharBase.EnumCharBaseB))
+    assertEquals('a'.toByte(), EnumExplicitCharA)
+    assertEquals('b'.toByte(), EnumExplicitCharB)
+    assertEquals(EnumExplicitCharA, EnumExplicitCharDup)
 
     assertEquals(49, sendV4I(vectorOf(1, 2, 3, 4)))
     assertEquals(49, (sendV4F(vectorOf(1f, 2f, 3f, 4f)) + 0.00001).toInt())