From 25f2c513f6f4492b23d62579298f5676038e74eb Mon Sep 17 00:00:00 2001
From: Dmitrii Gridin <dmitry.gridin@jetbrains.com>
Date: Mon, 8 May 2023 15:00:27 +0200
Subject: [PATCH] [LL FIR] drop global phase lock for super types phase

^KT-56551
---
 .../api/fir/file/builder/LLFirLockProvider.kt |  2 -
 .../LLFirSupertypeLazyResolver.kt             | 44 ++++++++++---------
 2 files changed, 24 insertions(+), 22 deletions(-)

diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/file/builder/LLFirLockProvider.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/file/builder/LLFirLockProvider.kt
index d81ff02b7cf..36a0053dca6 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/file/builder/LLFirLockProvider.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/file/builder/LLFirLockProvider.kt
@@ -27,7 +27,6 @@ import org.jetbrains.kotlin.fir.declarations.FirFile
 internal class LLFirLockProvider(private val checker: LLFirLazyResolveContractChecker) {
     private val globalLock = ReentrantLock()
 
-    private val superTypesLock = ReentrantLock()
     private val implicitTypesLock = ReentrantLock()
     private val statusLock = ReentrantLock()
     private val compilerAnnotationsLock = ReentrantLock()
@@ -55,7 +54,6 @@ internal class LLFirLockProvider(private val checker: LLFirLazyResolveContractCh
         val lock = when (phase) {
             FirResolvePhase.IMPLICIT_TYPES_BODY_RESOLVE -> implicitTypesLock
             FirResolvePhase.STATUS -> statusLock
-            FirResolvePhase.SUPER_TYPES -> superTypesLock
             FirResolvePhase.COMPILER_REQUIRED_ANNOTATIONS -> compilerAnnotationsLock
             else -> null
         }
diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/transformers/LLFirSupertypeLazyResolver.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/transformers/LLFirSupertypeLazyResolver.kt
index 6e418532fdb..f1d1bcd8c9c 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/transformers/LLFirSupertypeLazyResolver.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/transformers/LLFirSupertypeLazyResolver.kt
@@ -110,7 +110,12 @@ private class LLFirSuperTypeTargetResolver(
         when (target) {
             is FirRegularClass -> performResolve(
                 declaration = target,
-                resolver = { target.resolveSupertypeRefs() },
+                superTypeRefsForTransformation = {
+                    // We should create a copy of the original collection
+                    // to avoid [ConcurrentModificationException] during another thread publication
+                    ArrayList(target.superTypeRefs)
+                },
+                resolver = { supertypeResolver.resolveSpecificClassLikeSupertypes(target, it) },
                 superTypeUpdater = {
                     target.replaceSuperTypeRefs(it)
                     session.platformSupertypeUpdater?.updateSupertypesIfNeeded(target, scopeSession)
@@ -118,7 +123,8 @@ private class LLFirSuperTypeTargetResolver(
             )
             is FirTypeAlias -> performResolve(
                 declaration = target,
-                resolver = { target.resolveExpandedTypeRef() },
+                superTypeRefsForTransformation = { target.expandedTypeRef },
+                resolver = { supertypeResolver.resolveTypeAliasSupertype(target, it, resolveRecursively = false) },
                 superTypeUpdater = { target.replaceExpandedTypeRef(it.single()) },
             )
             else -> performCustomResolveUnderLock(target) {
@@ -129,24 +135,13 @@ private class LLFirSuperTypeTargetResolver(
         return true
     }
 
-    private fun FirRegularClass.resolveSupertypeRefs(): List<FirResolvedTypeRef> {
-        val superTypeRefs = superTypeRefs
-        /**
-         * TODO: KT-56551 this is safe, because we have a global phase lock
-         * Without such lock we should make a copy of [superTypeRefs] under a lock or
-         * FirRegularClassImpl should have "var superTypeRefs" + assign instead of "val superTypeRefs" + mutation
-         */
-        return supertypeResolver.resolveSpecificClassLikeSupertypes(this, superTypeRefs)
-    }
-
-    private fun FirTypeAlias.resolveExpandedTypeRef(): List<FirResolvedTypeRef> {
-        val expandedTypeRef = expandedTypeRef
-        return supertypeResolver.resolveTypeAliasSupertype(this, expandedTypeRef, resolveRecursively = false)
-    }
-
-    private inline fun <T : FirClassLikeDeclaration> performResolve(
+    /**
+     * [superTypeRefsForTransformation] will be executed under [declaration] lock
+     */
+    private inline fun <T : FirClassLikeDeclaration, S> performResolve(
         declaration: T,
-        resolver: () -> List<FirResolvedTypeRef>,
+        superTypeRefsForTransformation: () -> S,
+        resolver: (S) -> List<FirResolvedTypeRef>,
         crossinline superTypeUpdater: (List<FirTypeRef>) -> Unit,
     ) {
         // To avoid redundant work, because a publication won't be executed
@@ -154,8 +149,17 @@ private class LLFirSuperTypeTargetResolver(
 
         declaration.lazyResolveToPhase(resolverPhase.previous)
 
+        var superTypeRefs: S? = null
+        withReadLock(declaration) {
+            superTypeRefs = superTypeRefsForTransformation()
+        }
+
+        // "null" means that some other thread is already resolved [declaration] to [resolverPhase]
+        if (superTypeRefs == null) return
+
         // 1. Resolve declaration super type refs
-        val resolvedSuperTypeRefs = resolver()
+        @Suppress("UNCHECKED_CAST")
+        val resolvedSuperTypeRefs = resolver(superTypeRefs as S)
 
         // 2. Resolve super declarations
         val status = supertypeComputationSession.getSupertypesComputationStatus(declaration)