From 3b3734f0bbbe28aabb47f152578c78d506a8c0eb Mon Sep 17 00:00:00 2001
From: Dmitry Petrov <dmitry.petrov@jetbrains.com>
Date: Mon, 14 Feb 2022 16:16:02 +0300
Subject: [PATCH] JVM_IR simplify RenameFieldsLowering

---
 .../backend/jvm/lower/RenameFieldsLowering.kt | 98 +++----------------
 1 file changed, 13 insertions(+), 85 deletions(-)

diff --git a/compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/RenameFieldsLowering.kt b/compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/RenameFieldsLowering.kt
index ad94d4c67e6..dea11b85bfc 100644
--- a/compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/RenameFieldsLowering.kt
+++ b/compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/RenameFieldsLowering.kt
@@ -5,36 +5,22 @@
 
 package org.jetbrains.kotlin.backend.jvm.lower
 
+import org.jetbrains.kotlin.backend.common.ClassLoweringPass
 import org.jetbrains.kotlin.backend.common.CommonBackendContext
-import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
-import org.jetbrains.kotlin.ir.IrElement
-import org.jetbrains.kotlin.ir.IrStatement
-import org.jetbrains.kotlin.ir.builders.declarations.buildField
-import org.jetbrains.kotlin.ir.declarations.IrDeclarationParent
-import org.jetbrains.kotlin.ir.declarations.IrField
-import org.jetbrains.kotlin.ir.declarations.IrFile
-import org.jetbrains.kotlin.ir.expressions.IrExpression
-import org.jetbrains.kotlin.ir.expressions.IrGetField
-import org.jetbrains.kotlin.ir.expressions.IrSetField
-import org.jetbrains.kotlin.ir.expressions.impl.IrGetFieldImpl
-import org.jetbrains.kotlin.ir.expressions.impl.IrSetFieldImpl
-import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
-import org.jetbrains.kotlin.ir.util.patchDeclarationParents
-import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
-import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
+import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.kotlin.ir.util.fields
 import org.jetbrains.kotlin.name.Name
 
-internal val renameFieldsPhase = makeIrFilePhase(
-    ::RenameFieldsLowering,
+internal val renameFieldsPhase = makeIrFilePhase<CommonBackendContext>(
+    { RenameFieldsLowering() },
     name = "RenameFields",
     description = "Rename private fields (including fields copied from companion object) to avoid JVM declaration clash"
 )
 
-private class RenameFieldsLowering(val context: CommonBackendContext) : FileLoweringPass {
-    override fun lower(irFile: IrFile) {
-        val fields = mutableListOf<IrField>()
-        irFile.accept(FieldCollector, fields)
+private class RenameFieldsLowering : ClassLoweringPass {
+    override fun lower(irClass: IrClass) {
+        val fields = irClass.fields.toMutableList()
         fields.sortBy {
             when {
                 // We never rename public ABI fields (public and protected visibility) since they are accessible from Java
@@ -51,72 +37,14 @@ private class RenameFieldsLowering(val context: CommonBackendContext) : FileLowe
             }
         }
 
-        val newNames = mutableMapOf<IrField, Name>()
-        val count = hashMapOf<Pair<IrDeclarationParent, Name>, Int>()
+        val count = hashMapOf<Name, Int>()
         for (field in fields) {
-            val key = field.parent to field.name
-            val index = count[key] ?: 0
+            val oldName = field.name
+            val index = count[oldName] ?: 0
             if (index != 0 && !field.visibility.isPublicAPI) {
-                newNames[field] = Name.identifier("${field.name}$$index")
+                field.name = Name.identifier("$oldName$$index")
             }
-            count[key] = index + 1
-        }
-
-        val renamer = FieldRenamer(newNames)
-        irFile.transform(renamer, null)
-        irFile.transform(FieldAccessTransformer(renamer.newSymbols), null)
-    }
-}
-
-private object FieldCollector : IrElementVisitor<Unit, MutableList<IrField>> {
-    override fun visitElement(element: IrElement, data: MutableList<IrField>) {
-        element.acceptChildren(this, data)
-    }
-
-    override fun visitField(declaration: IrField, data: MutableList<IrField>) {
-        data.add(declaration)
-    }
-}
-
-private class FieldRenamer(private val newNames: Map<IrField, Name>) : IrElementTransformerVoid() {
-    val newSymbols = mutableMapOf<IrField, IrFieldSymbol>()
-
-    override fun visitField(declaration: IrField): IrStatement {
-        val newName = newNames[declaration] ?: return super.visitField(declaration)
-        return declaration.factory.buildField {
-            updateFrom(declaration)
-            name = newName
-        }.also {
-            it.parent = declaration.parent
-            it.initializer = declaration.initializer
-                ?.transform(this, null)
-                ?.patchDeclarationParents(it)
-
-            newSymbols[declaration] = it.symbol
+            count[oldName] = index + 1
         }
     }
 }
-
-private class FieldAccessTransformer(private val oldToNew: Map<IrField, IrFieldSymbol>) : IrElementTransformerVoid() {
-    override fun visitGetField(expression: IrGetField): IrExpression {
-        val newSymbol = oldToNew[expression.symbol.owner] ?: return super.visitGetField(expression)
-
-        return IrGetFieldImpl(
-            expression.startOffset, expression.endOffset, newSymbol, expression.type,
-            expression.receiver?.transform(this, null),
-            expression.origin, expression.superQualifierSymbol
-        )
-    }
-
-    override fun visitSetField(expression: IrSetField): IrExpression {
-        val newSymbol = oldToNew[expression.symbol.owner] ?: return super.visitSetField(expression)
-
-        return IrSetFieldImpl(
-            expression.startOffset, expression.endOffset, newSymbol,
-            expression.receiver?.transform(this, null),
-            expression.value.transform(this, null),
-            expression.type,
-            expression.origin, expression.superQualifierSymbol
-        )
-    }
-}