Support basic interpretation of IrGetClass

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/ir/interpreter/IrInterpreterAfterFir2IrTestGenerated.java

@@ -694,6 +694,12 @@ public class IrInterpreterAfterFir2IrTestGenerated extends AbstractIrInterpreter
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/ir/interpreter/reference"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
         }
 
+        @Test
+        @TestMetadata("getClass.kt")
+        public void testGetClass() throws Exception {
+            runTest("compiler/testData/ir/interpreter/reference/getClass.kt");
+        }
+
         @Test
         @TestMetadata("propertyReference.kt")
         public void testPropertyReference() throws Exception {

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/ir/interpreter/IrInterpreterAfterPsi2IrTestGenerated.java

@@ -694,6 +694,12 @@ public class IrInterpreterAfterPsi2IrTestGenerated extends AbstractIrInterpreter
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/ir/interpreter/reference"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
         }
 
+        @Test
+        @TestMetadata("getClass.kt")
+        public void testGetClass() throws Exception {
+            runTest("compiler/testData/ir/interpreter/reference/getClass.kt");
+        }
+
         @Test
         @TestMetadata("propertyReference.kt")
         public void testPropertyReference() throws Exception {

compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/InstructionsUnfolder.kt

@@ -68,6 +68,7 @@ internal fun unfoldInstruction(element: IrElement?, environment: IrInterpreterEn
         is IrFunctionReference -> unfoldFunctionReference(element, callStack)
         is IrPropertyReference -> unfoldPropertyReference(element, callStack)
         is IrClassReference -> unfoldClassReference(element, callStack)
+        is IrGetClass -> unfoldGetClass(element, callStack)
         is IrComposite -> unfoldComposite(element, callStack)
 
         else -> TODO("${element.javaClass} not supported")
@@ -401,4 +402,9 @@ private fun unfoldPropertyReference(propertyReference: IrPropertyReference, call
 
 private fun unfoldClassReference(classReference: IrClassReference, callStack: CallStack) {
     callStack.addInstruction(SimpleInstruction(classReference))
+}
+
+private fun unfoldGetClass(element: IrGetClass, callStack: CallStack) {
+    callStack.addInstruction(SimpleInstruction(element))
+    callStack.addInstruction(CompoundInstruction(element.argument))
 }

compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/IrInterpreter.kt

@@ -132,6 +132,7 @@ class IrInterpreter private constructor(
             is IrFunctionReference -> interpretFunctionReference(element)
             is IrPropertyReference -> interpretPropertyReference(element)
             is IrClassReference -> interpretClassReference(element)
+            is IrGetClass -> interpretGetClass(element)
             else -> TODO("${element.javaClass} not supported for interpretation")
         }
     }
@@ -616,4 +617,9 @@ class IrInterpreter private constructor(
             else -> callStack.pushState(KClassState(classReference))
         }
     }
+
+    private fun interpretGetClass(expression: IrGetClass) {
+        val irClass = callStack.popState().irClass
+        callStack.pushState(KClassState(irClass, expression.type.classOrNull!!.owner))
+    }
 }

compiler/testData/ir/interpreter/reference/getClass.kt

@@ -0,0 +1,13 @@
+import kotlin.*
+
+fun test(a: Any) = when (a::class) {
+    String::class -> "String"
+    Int::class -> "Int"
+    Boolean::class -> "Boolean"
+    else -> "Else"
+}
+
+const val a = <!EVALUATED: `String`!>test("")<!>
+const val b = <!EVALUATED: `Int`!>test(1)<!>
+const val c = <!EVALUATED: `Boolean`!>test(true)<!>
+const val d = <!EVALUATED: `Else`!>test(2.0)<!>