FIR: Optimize constructor of FirTowerResolverSession

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/Collections.kt

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2010-2020 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.fir
+
+private open class FrozenReversedListReadOnly<out T>(
+    private val delegate: List<T>
+) : AbstractList<T>() {
+    override val size: Int = delegate.size
+    override fun get(index: Int): T = delegate[size - 1 - index]
+}
+
+fun <T> List<T>.asReversedFrozen(): List<T> = FrozenReversedListReadOnly(this)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/BodyResolveComponents.kt

@@ -39,6 +39,7 @@ interface BodyResolveComponents : SessionHolder {
     val containingDeclarations: List<FirDeclaration>
     val fileImportsScope: List<FirScope>
     val towerDataElements: List<FirTowerDataElement>
+    val towerDataContext: FirTowerDataContext
     val localScopes: FirLocalScopes
     val towerDataContextForAnonymousFunctions: TowerDataContextForAnonymousFunctions
     val noExpectedType: FirTypeRef
@@ -68,12 +69,14 @@ class FirTowerDataContext private constructor(
     // i.e. implicitReceiverStack == towerDataElements.mapNotNull { it.receiver }
     // i.e. localScopes == towerDataElements.mapNotNull { it.scope?.takeIf { it.isLocal } }
     val implicitReceiverStack: PersistentImplicitReceiverStack,
-    val localScopes: FirLocalScopes
+    val localScopes: FirLocalScopes,
+    val nonLocalTowerDataElements: PersistentList<FirTowerDataElement>
 ) {
 
     constructor() : this(
         persistentListOf(),
         PersistentImplicitReceiverStack(),
+        persistentListOf(),
         persistentListOf()
     )
 
@@ -84,7 +87,8 @@ class FirTowerDataContext private constructor(
         return FirTowerDataContext(
             towerDataElements.set(indexOfLastLocalScope, newLastScope.asTowerDataElement(isLocal = true)),
             implicitReceiverStack,
-            localScopes.set(localScopes.lastIndex, newLastScope)
+            localScopes.set(localScopes.lastIndex, newLastScope),
+            nonLocalTowerDataElements
         )
     }
 
@@ -92,7 +96,8 @@ class FirTowerDataContext private constructor(
         return FirTowerDataContext(
             towerDataElements.addAll(newElements),
             implicitReceiverStack.addAll(newElements.mapNotNull { it.implicitReceiver }),
-            localScopes
+            localScopes,
+            nonLocalTowerDataElements.addAll(newElements)
         )
     }
 
@@ -100,15 +105,18 @@ class FirTowerDataContext private constructor(
         return FirTowerDataContext(
             towerDataElements.add(localScope.asTowerDataElement(isLocal = true)),
             implicitReceiverStack,
-            localScopes.add(localScope)
+            localScopes.add(localScope),
+            nonLocalTowerDataElements
         )
     }
 
     fun addReceiver(name: Name?, implicitReceiverValue: ImplicitReceiverValue<*>): FirTowerDataContext {
+        val element = implicitReceiverValue.asTowerDataElement()
         return FirTowerDataContext(
-            towerDataElements.add(implicitReceiverValue.asTowerDataElement()),
+            towerDataElements.add(element),
             implicitReceiverStack.add(name, implicitReceiverValue),
-            localScopes
+            localScopes,
+            nonLocalTowerDataElements.add(element)
         )
     }
 
@@ -118,10 +126,12 @@ class FirTowerDataContext private constructor(
     }
 
     private fun addNonLocalScope(scope: FirScope): FirTowerDataContext {
+        val element = scope.asTowerDataElement(isLocal = false)
         return FirTowerDataContext(
-            towerDataElements.add(scope.asTowerDataElement(isLocal = false)),
+            towerDataElements.add(element),
             implicitReceiverStack,
-            localScopes
+            localScopes,
+            nonLocalTowerDataElements.add(element)
         )
     }
 }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirTowerResolverSession.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.fir.resolve.calls.tower
 
 import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.asReversedFrozen
 import org.jetbrains.kotlin.fir.declarations.isInner
 import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.FirQualifiedAccessExpression
@@ -43,16 +44,12 @@ class FirTowerResolverSession internal constructor(
 
     private val session: FirSession get() = components.session
 
-    private val reversedTowerDataElements = components.towerDataElements.asReversed()
+    private val localScopes: List<FirScope> = components.localScopes.asReversedFrozen()
 
-    private val localScopes: List<FirScope> = reversedTowerDataElements.mapNotNull { lexical ->
-        lexical.scope?.takeIf { lexical.isLocal }
-    }
-
-    private val nonLocalLexical = reversedTowerDataElements.filter { !it.isLocal }
+    private val nonLocalTowerDataElements = components.towerDataContext.nonLocalTowerDataElements.asReversedFrozen()
 
     private val implicitReceivers: List<ImplicitReceiver> by lazy(LazyThreadSafetyMode.NONE) {
-        reversedTowerDataElements.withIndex().mapNotNull { (index, element) ->
+        nonLocalTowerDataElements.withIndex().mapNotNull { (index, element) ->
             element.implicitReceiver?.let { ImplicitReceiver(it, index) }
         }
     }
@@ -404,7 +401,7 @@ class FirTowerResolverSession internal constructor(
             onLocalScope(index, localScope)
         }
 
-        for ((depth, lexical) in nonLocalLexical.withIndex()) {
+        for ((depth, lexical) in nonLocalTowerDataElements.withIndex()) {
             if (!lexical.isLocal && lexical.scope != null) {
                 onNonLocalScope(depth, lexical.scope)
             }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirAbstractBodyResolveTransformer.kt

@@ -245,6 +245,9 @@ abstract class FirAbstractBodyResolveTransformer(phase: FirResolvePhase) : FirAb
         override val fileImportsScope: List<FirScope> get() = context.fileImportsScope
         override val towerDataElements: List<FirTowerDataElement> get() = context.towerDataContext.towerDataElements
         override val localScopes: FirLocalScopes get() = context.towerDataContext.localScopes
+
+        override val towerDataContext: FirTowerDataContext get() = context.towerDataContext
+
         override val file: FirFile get() = context.file
         override val implicitReceiverStack: ImplicitReceiverStack get() = context.implicitReceiverStack
         override val containingDeclarations: List<FirDeclaration> get() = context.containers