From 8f963bed7cc6585a43afbada99e415d5dd81096b Mon Sep 17 00:00:00 2001
From: Andrey Uskov <andrey.uskov@jetbrains.com>
Date: Wed, 15 Sep 2021 23:08:36 +0300
Subject: [PATCH] Optimized performance of recordPackageLookup

#KT-47909 Fixed
---
 .../kotlin/incremental/LookupStorage.kt       | 35 +++++++++++++++----
 .../incremental/KotlinLookupLocation.kt       | 26 +++++++-------
 2 files changed, 43 insertions(+), 18 deletions(-)

diff --git a/build-common/src/org/jetbrains/kotlin/incremental/LookupStorage.kt b/build-common/src/org/jetbrains/kotlin/incremental/LookupStorage.kt
index bf100df6ea9..c8b8c8a3dba 100644
--- a/build-common/src/org/jetbrains/kotlin/incremental/LookupStorage.kt
+++ b/build-common/src/org/jetbrains/kotlin/incremental/LookupStorage.kt
@@ -224,13 +224,36 @@ class LookupTrackerImpl(private val delegate: LookupTracker) : LookupTracker {
     override val requiresPosition: Boolean
         get() = delegate.requiresPosition
 
-    override fun record(filePath: String, position: Position, scopeFqName: String, scopeKind: ScopeKind, name: String) {
-        val internedScopeFqName = interner.intern(scopeFqName)
-        val internedName = interner.intern(name)
-        val internedFilePath = pathInterner.intern(filePath)
+    var prevFilePath: String = ""
+    var prevPosition: Position? = null
+    var prevScopeFqName: String = ""
+    var prevScopeKind: ScopeKind? = null
+    var prevName: String = ""
 
-        lookups.putValue(LookupSymbol(internedName, internedScopeFqName), internedFilePath)
-        delegate.record(internedFilePath, position, internedScopeFqName, scopeKind, internedName)
+    // This method is very hot and sequential invocations usually have the same parameters. Thus we cache previous parameters
+    override fun record(filePath: String, position: Position, scopeFqName: String, scopeKind: ScopeKind, name: String) {
+        val nameChanged = if (name != prevName) {
+            prevName = interner.intern(name)
+            true
+        } else false
+        val fqNameChanged = if (scopeFqName != prevScopeFqName) {
+            prevScopeFqName = interner.intern(scopeFqName)
+            true
+        } else false
+        val filePathChanged = if (filePath != prevFilePath) {
+            prevFilePath = pathInterner.intern(filePath)
+            true
+        } else false
+
+        val lookupChanged = nameChanged || fqNameChanged || filePathChanged
+        if (lookupChanged) {
+            lookups.putValue(LookupSymbol(prevName, prevScopeFqName), prevFilePath)
+        }
+        if (lookupChanged || prevPosition != position || prevScopeKind != scopeKind) {
+            prevPosition = position
+            prevScopeKind = scopeKind
+            delegate.record(prevFilePath, position, prevScopeFqName, scopeKind, prevName)
+        }
     }
 }
 
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/incremental/KotlinLookupLocation.kt b/compiler/frontend/src/org/jetbrains/kotlin/incremental/KotlinLookupLocation.kt
index 248972b9d9f..2cce4df6a18 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/incremental/KotlinLookupLocation.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/incremental/KotlinLookupLocation.kt
@@ -24,18 +24,20 @@ import org.jetbrains.kotlin.psi.KtElement
 import org.jetbrains.kotlin.psi.doNotAnalyze
 
 class KotlinLookupLocation(val element: KtElement) : LookupLocation {
+    val cachedLocation : LocationInfo? by lazy {
+        val containingJetFile = element.containingKtFile
+
+        if (containingJetFile.doNotAnalyze != null)
+            null
+        else
+            object : LocationInfo {
+            override val filePath = containingJetFile.virtualFilePath
+
+            override val position: Position
+                get() = getLineAndColumnInPsiFile(containingJetFile, element.textRange).let { Position(it.line, it.column) }
+        }
+    }
 
     override val location: LocationInfo?
-        get() {
-            val containingJetFile = element.containingKtFile
-
-            if (containingJetFile.doNotAnalyze != null) return null
-
-            return object : LocationInfo {
-                override val filePath = containingJetFile.virtualFilePath
-
-                override val position: Position
-                    get() = getLineAndColumnInPsiFile(containingJetFile, element.textRange).let { Position(it.line, it.column) }
-            }
-        }
+        get() = cachedLocation
 }