IR: make mapOptimized non-inline, rename to transformIfNeeded

This seems to have no effect on performance, however it clearly shows
that this method is a hotspot now with regard to own CPU samples.
Furthermore, it somewhat decreases the bytecode size at call sites and
might actually allow the HotSpot to inline those methods earlier and
hopefully deoptimize less frequently.

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyClass.kt

@@ -6,8 +6,9 @@
 package org.jetbrains.kotlin.fir.lazy
 
 import org.jetbrains.kotlin.descriptors.*
-import org.jetbrains.kotlin.fir.backend.*
+import org.jetbrains.kotlin.fir.backend.Fir2IrComponents
 import org.jetbrains.kotlin.fir.backend.declareThisReceiverParameter
+import org.jetbrains.kotlin.fir.backend.toIrType
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.resolve.buildUseSiteMemberScope
 import org.jetbrains.kotlin.fir.symbols.Fir2IrClassSymbol
@@ -19,8 +20,8 @@ import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.lazy.lazyVar
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeImpl
-import org.jetbrains.kotlin.ir.util.mapOptimized
 import org.jetbrains.kotlin.ir.util.transform
+import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
@@ -190,7 +191,7 @@ class Fir2IrLazyClass(
 
     override fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D) {
         thisReceiver = thisReceiver?.transform(transformer, data)
-        typeParameters = typeParameters.mapOptimized { it.transform(transformer, data) }
+        typeParameters = typeParameters.transformIfNeeded(transformer, data)
         declarations.transform { it.transform(transformer, data) }
     }
 }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyConstructor.kt

@@ -20,8 +20,8 @@ import org.jetbrains.kotlin.ir.declarations.IrValueParameter
 import org.jetbrains.kotlin.ir.declarations.lazy.lazyVar
 import org.jetbrains.kotlin.ir.expressions.IrBody
 import org.jetbrains.kotlin.ir.types.IrType
-import org.jetbrains.kotlin.ir.util.mapOptimized
 import org.jetbrains.kotlin.ir.util.parentClassOrNull
+import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
@@ -125,11 +125,11 @@ class Fir2IrLazyConstructor(
     }
 
     override fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D) {
-        typeParameters = typeParameters.mapOptimized { it.transform(transformer, data) }
+        typeParameters = typeParameters.transformIfNeeded(transformer, data)
 
         dispatchReceiverParameter = dispatchReceiverParameter?.transform(transformer, data)
         extensionReceiverParameter = extensionReceiverParameter?.transform(transformer, data)
-        valueParameters = valueParameters.mapOptimized { it.transform(transformer, data) }
+        valueParameters = valueParameters.transformIfNeeded(transformer, data)
 
         body = body?.transform(transformer, data)
     }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazySimpleFunction.kt

@@ -21,7 +21,7 @@ import org.jetbrains.kotlin.ir.expressions.IrBody
 import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.types.IrType
-import org.jetbrains.kotlin.ir.util.mapOptimized
+import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
@@ -147,11 +147,11 @@ class Fir2IrLazySimpleFunction(
     }
 
     override fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D) {
-        typeParameters = typeParameters.mapOptimized { it.transform(transformer, data) }
+        typeParameters = typeParameters.transformIfNeeded(transformer, data)
 
         dispatchReceiverParameter = dispatchReceiverParameter?.transform(transformer, data)
         extensionReceiverParameter = extensionReceiverParameter?.transform(transformer, data)
-        valueParameters = valueParameters.mapOptimized { it.transform(transformer, data) }
+        valueParameters = valueParameters.transformIfNeeded(transformer, data)
 
         body = body?.transform(transformer, data)
     }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrClassImpl.kt

@@ -23,7 +23,7 @@ import org.jetbrains.kotlin.ir.declarations.impl.carriers.ClassCarrier
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.transform
-import org.jetbrains.kotlin.ir.util.mapOptimized
+import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
@@ -177,7 +177,7 @@ class IrClassImpl(
 
     override fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D) {
         thisReceiver = thisReceiver?.transform(transformer, data)
-        typeParameters = typeParameters.mapOptimized { it.transform(transformer, data) }
+        typeParameters = typeParameters.transformIfNeeded(transformer, data)
         declarations.transform { it.transform(transformer, data) }
     }
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFunctionBase.kt

@@ -22,7 +22,7 @@ import org.jetbrains.kotlin.ir.declarations.impl.carriers.FunctionBaseCarrier
 import org.jetbrains.kotlin.ir.expressions.IrBody
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.impl.IrUninitializedType
-import org.jetbrains.kotlin.ir.util.mapOptimized
+import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
@@ -144,12 +144,11 @@ abstract class IrFunctionBase<T : FunctionBaseCarrier<T>>(
     }
 
     override fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D) {
-
+        typeParameters = typeParameters.transformIfNeeded(transformer, data)
-        typeParameters = typeParameters.mapOptimized { it.transform(transformer, data) }
 
         dispatchReceiverParameter = dispatchReceiverParameter?.transform(transformer, data)
         extensionReceiverParameter = extensionReceiverParameter?.transform(transformer, data)
-        valueParameters = valueParameters.mapOptimized { it.transform(transformer, data) }
+        valueParameters = valueParameters.transformIfNeeded(transformer, data)
 
         body = body?.transform(transformer, data)
     }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeAliasImpl.kt

@@ -14,7 +14,7 @@ import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.TypeAliasCarrier
 import org.jetbrains.kotlin.ir.symbols.IrTypeAliasSymbol
 import org.jetbrains.kotlin.ir.types.IrType
-import org.jetbrains.kotlin.ir.util.mapOptimized
+import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
@@ -59,7 +59,7 @@ class IrTypeAliasImpl(
     }
 
     override fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D) {
-        typeParameters = typeParameters.mapOptimized { it.transform(transformer, data) }
+        typeParameters = typeParameters.transformIfNeeded(transformer, data)
     }
 
     companion object {
@@ -81,4 +81,4 @@ class IrTypeAliasImpl(
                 origin
             )
     }
-}
+}

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyClass.kt

@@ -13,7 +13,7 @@ import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.DeclarationStubGenerator
 import org.jetbrains.kotlin.ir.util.TypeTranslator
 import org.jetbrains.kotlin.ir.util.transform
-import org.jetbrains.kotlin.ir.util.mapOptimized
+import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.metadata.ProtoBuf
@@ -102,7 +102,7 @@ class IrLazyClass(
 
     override fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D) {
         thisReceiver = thisReceiver?.transform(transformer, data)
-        typeParameters = typeParameters.mapOptimized { it.transform(transformer, data) }
+        typeParameters = typeParameters.transformIfNeeded(transformer, data)
         declarations.transform { it.transform(transformer, data) }
     }
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyFunctionBase.kt

@@ -14,7 +14,7 @@ import org.jetbrains.kotlin.ir.expressions.IrBody
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.DeclarationStubGenerator
 import org.jetbrains.kotlin.ir.util.TypeTranslator
-import org.jetbrains.kotlin.ir.util.mapOptimized
+import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
@@ -77,12 +77,12 @@ abstract class IrLazyFunctionBase(
     }
 
     override fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D) {
-        typeParameters = typeParameters.mapOptimized { it.transform(transformer, data) }
+        typeParameters = typeParameters.transformIfNeeded(transformer, data)
 
         dispatchReceiverParameter = dispatchReceiverParameter?.transform(transformer, data)
         extensionReceiverParameter = extensionReceiverParameter?.transform(transformer, data)
-        valueParameters = valueParameters.mapOptimized { it.transform(transformer, data) }
+        valueParameters = valueParameters.transformIfNeeded(transformer, data)
 
         body = body?.transform(transformer, data)
     }
-}
+}

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeAlias.kt

@@ -16,7 +16,7 @@ import org.jetbrains.kotlin.ir.symbols.IrTypeAliasSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.DeclarationStubGenerator
 import org.jetbrains.kotlin.ir.util.TypeTranslator
-import org.jetbrains.kotlin.ir.util.mapOptimized
+import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
@@ -63,6 +63,6 @@ class IrLazyTypeAlias(
     }
 
     override fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D) {
-        typeParameters = typeParameters.mapOptimized { it.transform(transformer, data) }
+        typeParameters = typeParameters.transformIfNeeded(transformer, data)
     }
-}
+}

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/transform.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.ir.util
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationContainer
+import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 
 inline fun <reified T : IrElement> MutableList<T>.transform(transformation: (T) -> IrElement) {
     forEachIndexed { i, item ->
@@ -65,16 +66,17 @@ fun IrDeclarationContainer.transformDeclarationsFlat(transformation: (IrDeclarat
 }
 
 /**
- * Similar to `map`. Return the same List instance if no element instances have changed.
+ * Transforms the list of elements with the given transformer. Return the same List instance if no element instances have changed.
  */
-inline fun <reified T : IrElement> List<T>.mapOptimized(transformation: (T) -> IrElement): List<T> {
+fun <T : IrElement, D> List<T>.transformIfNeeded(transformer: IrElementTransformer<D>, data: D): List<T> {
     var result: ArrayList<T>? = null
     for ((i, item) in withIndex()) {
-        val transformed = transformation(item) as T
+        @Suppress("UNCHECKED_CAST")
+        val transformed = item.transform(transformer, data) as T
         if (transformed !== item && result == null) {
             result = ArrayList(this)
         }
         result?.set(i, transformed)
     }
     return result ?: this
-}
+}