[K/N] Extract const val initializers to place of usage

This would make behaviour more consistent with jvm. There is still
a difference in behaviour about point where side effects happen.

^KT-52970

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/InlineConstTransformer.kt

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2010-2022 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 org.jetbrains.kotlin.backend.common.lower
+
+import org.jetbrains.kotlin.ir.declarations.IrField
+import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
+import org.jetbrains.kotlin.ir.expressions.*
+import org.jetbrains.kotlin.ir.expressions.impl.IrCompositeImpl
+import org.jetbrains.kotlin.ir.expressions.impl.IrGetFieldImpl
+import org.jetbrains.kotlin.ir.expressions.impl.copyWithOffsets
+import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
+
+abstract class InlineConstTransformer : IrElementTransformerVoid() {
+    abstract val IrField.constantInitializer: IrConst<*>?
+    private fun IrExpression.lowerConstRead(receiver: IrExpression?, field: IrField?): IrExpression? {
+        val value = field?.constantInitializer ?: return null
+        transformChildrenVoid()
+        reportInlineConst(field, value)
+
+        val resultExpression = value.copyWithOffsets(startOffset, endOffset)
+
+        return if (receiver == null || receiver.shouldDropConstReceiver())
+            resultExpression
+        else
+            IrCompositeImpl(
+                startOffset, endOffset, resultExpression.type, null,
+                listOf(receiver, resultExpression)
+            )
+    }
+
+    abstract fun reportInlineConst(field: IrField, value: IrConst<*>)
+
+    abstract fun IrExpression.shouldDropConstReceiver(): Boolean
+
+    override fun visitCall(expression: IrCall): IrExpression {
+        val function = (expression.symbol.owner as? IrSimpleFunction) ?: return super.visitCall(expression)
+        val property = function.correspondingPropertySymbol?.owner ?: return super.visitCall(expression)
+        // If `constantValue` is not null, `function` can only be the getter because the property is immutable.
+        return expression.lowerConstRead(expression.dispatchReceiver, property.backingField) ?: super.visitCall(expression)
+    }
+
+    override fun visitGetField(expression: IrGetField): IrExpression =
+        expression.lowerConstRead(expression.receiver, expression.symbol.owner) ?: super.visitGetField(expression)
+}

compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/ConstLowering.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.backend.jvm.lower
 
 import org.jetbrains.kotlin.backend.common.FileLoweringPass
+import org.jetbrains.kotlin.backend.common.lower.InlineConstTransformer
 import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
 import org.jetbrains.kotlin.backend.jvm.ir.constantValue
@@ -13,12 +14,8 @@ import org.jetbrains.kotlin.config.CommonConfigurationKeys
 import org.jetbrains.kotlin.incremental.components.InlineConstTracker
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
-import org.jetbrains.kotlin.ir.expressions.impl.IrCompositeImpl
-import org.jetbrains.kotlin.ir.expressions.impl.IrGetFieldImpl
-import org.jetbrains.kotlin.ir.expressions.impl.copyWithOffsets
 import org.jetbrains.kotlin.ir.util.classId
 import org.jetbrains.kotlin.ir.util.parentAsClass
-import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 
 internal val constPhase1 = makeIrFilePhase(
@@ -37,34 +34,12 @@ class ConstLowering(val context: JvmBackendContext) : FileLoweringPass {
     val inlineConstTracker =
         context.state.configuration[CommonConfigurationKeys.INLINE_CONST_TRACKER]
 
-    override fun lower(irFile: IrFile) = irFile.transformChildrenVoid(ConstTransformer(irFile, context, inlineConstTracker))
+    override fun lower(irFile: IrFile) = irFile.transformChildrenVoid(JvmInlineConstTransformer(irFile, inlineConstTracker))
 }
 
-private class ConstTransformer(
-    val irFile: IrFile,
-    val context: JvmBackendContext,
-    val inlineConstTracker: InlineConstTracker?
-) : IrElementTransformerVoid() {
-    private fun IrExpression.lowerConstRead(receiver: IrExpression?, field: IrField?): IrExpression? {
-        val value = field?.constantValue() ?: return null
-        transformChildrenVoid()
-        reportInlineConst(field, value)
-
-        val resultExpression = if (context.state.shouldInlineConstVals)
-            value.copyWithOffsets(startOffset, endOffset)
-        else
-            IrGetFieldImpl(startOffset, endOffset, field.symbol, field.type)
-
-        return if (receiver == null || receiver.shouldDropConstReceiver())
-            resultExpression
-        else
-            IrCompositeImpl(
-                startOffset, endOffset, resultExpression.type, null,
-                listOf(receiver, resultExpression)
-            )
-    }
-
-    private fun reportInlineConst(field: IrField, value: IrConst<*>) {
+private class JvmInlineConstTransformer(val irFile: IrFile, val inlineConstTracker: InlineConstTracker?) : InlineConstTransformer() {
+    override val IrField.constantInitializer get() = constantValue()
+    override fun reportInlineConst(field: IrField, value: IrConst<*>) {
         if (inlineConstTracker == null) return
         if (field.origin != IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB) return
 
@@ -76,17 +51,5 @@ private class ConstTransformer(
         inlineConstTracker.report(path, owner, name, constType)
     }
 
-    private fun IrExpression.shouldDropConstReceiver() =
-        this is IrConst<*> || this is IrGetValue ||
-                this is IrGetObjectValue
-
-    override fun visitCall(expression: IrCall): IrExpression {
-        val function = (expression.symbol.owner as? IrSimpleFunction) ?: return super.visitCall(expression)
-        val property = function.correspondingPropertySymbol?.owner ?: return super.visitCall(expression)
-        // If `constantValue` is not null, `function` can only be the getter because the property is immutable.
-        return expression.lowerConstRead(expression.dispatchReceiver, property.backingField) ?: super.visitCall(expression)
-    }
-
-    override fun visitGetField(expression: IrGetField): IrExpression =
-        expression.lowerConstRead(expression.receiver, expression.symbol.owner) ?: super.visitGetField(expression)
+    override fun IrExpression.shouldDropConstReceiver() = this is IrConst<*> || this is IrGetValue || this is IrGetObjectValue
 }