[K/N] Support pre-creating for objects with only constant properties

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/CodeGenerator.kt

@@ -20,28 +20,31 @@ import org.jetbrains.kotlin.backend.konan.ir.*
 import org.jetbrains.kotlin.backend.konan.llvm.ThreadState.Native
 import org.jetbrains.kotlin.backend.konan.llvm.ThreadState.Runnable
 import org.jetbrains.kotlin.descriptors.konan.CompiledKlibModuleOrigin
-import org.jetbrains.kotlin.ir.expressions.IrDelegatingConstructorCall
-import org.jetbrains.kotlin.ir.expressions.IrGetObjectValue
-import org.jetbrains.kotlin.ir.expressions.IrReturn
+import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.konan.ForeignExceptionMode
 
-private fun IrConstructor.isAnyConstructorDelegation(context: Context): Boolean {
-        val statements = this.body?.statements ?: return false
-        if (statements.size != 2) return false
-        val lastStatement = statements[1]
-        if (lastStatement !is IrReturn ||
-                (lastStatement.value as? IrGetObjectValue)?.symbol != context.irBuiltIns.unitClass) return false
-        val constructorCall = statements[0] as? IrDelegatingConstructorCall ?: return false
-        val constructor = constructorCall.symbol.owner as? IrConstructor ?: return false
-        return constructor.constructedClass.isAny()
+private fun IrConstructor.isAutogeneratedSimpleConstructor(context: Context): Boolean {
+    if (!this.isPrimary) return false
+    val statements = this.body?.statements ?: return false
+    if (statements.size < 2) return false
+    val lastStatement = statements.last()
+    if (lastStatement !is IrReturn ||
+            (lastStatement.value as? IrGetObjectValue)?.symbol != context.irBuiltIns.unitClass) return false
+    val constructorCall = statements[0] as? IrDelegatingConstructorCall ?: return false
+    val constructor = constructorCall.symbol.owner as? IrConstructor ?: return false
+    if (!constructor.constructedClass.isAny()) return false
+    return statements.asSequence().take(statements.size - 1).drop(1).all {
+        it is IrBlock && it.origin == IrStatementOrigin.INITIALIZE_FIELD
     }
+}
 
 // TODO: shall we memoize that property?
 internal fun IrClass.hasConstStateAndNoSideEffects(context: Context): Boolean {
     if (!context.shouldOptimize()) return false
     if (this.hasAnnotation(KonanFqNames.canBePrecreated)) return true
     val fields = context.getLayoutBuilder(this).fields
-    return fields.isEmpty() && this.constructors.all { it.isAnyConstructorDelegation(context) }
+    return fields.all { (it.correspondingPropertySymbol?.owner?.isConst ?: false) && (it.initializer?.expression is IrConst<*>) } &&
+            this.constructors.all { it.isAutogeneratedSimpleConstructor(context) }
 }
 
 internal class CodeGenerator(override val context: Context) : ContextUtils {

kotlin-native/backend.native/tests/build.gradle

@@ -1262,6 +1262,12 @@ task localClass_localHierarchy(type: KonanLocalTest) {
     source = "codegen/localClass/localHierarchy.kt"
 }
 
+standaloneTest("objectDeclaration_globalConstants") {
+    disabled = (cacheTesting != null) // Cache is not compatible with -opt.
+    flags = ["-opt", "-Xopt-in=kotlin.native.internal.InternalForKotlinNative", "-tr"]
+    source = "codegen/objectDeclaration/globalConstants.kt"
+}
+
 task localClass_objectExpressionInProperty(type: KonanLocalTest) {
     goldValue = "OK\n"
     source = "codegen/localClass/objectExpressionInProperty.kt"

kotlin-native/backend.native/tests/codegen/objectDeclaration/globalConstants.kt

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package codegen.objectDeclaration.globalConstants
+
+import kotlin.test.*
+import kotlin.native.internal.*
+
+object EmptyClass {}
+
+@Test fun checkEmptyClass() {
+    assertTrue(EmptyClass.isPermanent())
+}
+
+
+object ClassWithConstants {
+    const val A = 1
+    const val B = 2L
+    const val C = 3.0
+    const val D = 4.0f
+    const val E = 5.toShort()
+    const val F = 6.toByte()
+    const val G = "8"
+}
+
+@Test fun checkInit() {
+    assertTrue(ClassWithConstants.isPermanent())
+    assertEquals(1, ClassWithConstants.A)
+    assertEquals(2, ClassWithConstants.B)
+    assertEquals(3.0, ClassWithConstants.C)
+    assertEquals(4.0f, ClassWithConstants.D)
+    assertEquals(5, ClassWithConstants.E)
+    assertEquals(6, ClassWithConstants.F)
+    assertEquals("8", ClassWithConstants.G)
+
+    assertEquals(1, (ClassWithConstants::A)())
+    assertEquals(2, (ClassWithConstants::B)())
+    assertEquals(3.0, (ClassWithConstants::C)())
+    assertEquals(4.0f, (ClassWithConstants::D)())
+    assertEquals(5, (ClassWithConstants::E)())
+    assertEquals(6, (ClassWithConstants::F)())
+    assertEquals("8", (ClassWithConstants::G)())
+}
+
+
+var ClassWithConstructorInitialized = 0
+
+object ClassWithConstructor {
+    init {
+        ClassWithConstructorInitialized += 1
+    }
+    const val A = 1;
+}
+
+@Test fun checkConstructor() {
+    assertEquals(0, ClassWithConstructorInitialized)
+    assertEquals(1, ClassWithConstructor.A)
+    assertEquals(1, ClassWithConstructorInitialized)
+    assertEquals(1, ClassWithConstructor.A)
+    assertEquals(1, ClassWithConstructorInitialized)
+    assertFalse(ClassWithConstructor.isPermanent())
+}
+
+object ClassWithField {
+    val x = 4
+}
+
+@Test fun checkField() {
+    assertFalse(ClassWithField.isPermanent())
+}
+
+object ClassWithComputedField {
+    val x : Int
+       get() = 4
+}
+
+@Test fun checkComputedField() {
+    assertTrue(ClassWithComputedField.isPermanent())
+}