FIR IDE: cache function symbols in FirIdeBuiltinSymbolProvider

compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirBuiltinSymbolProvider.kt

@@ -50,7 +50,7 @@ import java.io.InputStream
 
 //TODO make thread safe
 @ThreadSafeMutableState
-class FirBuiltinSymbolProvider(session: FirSession, val kotlinScopeProvider: KotlinScopeProvider) : FirSymbolProvider(session) {
+open class FirBuiltinSymbolProvider(session: FirSession, val kotlinScopeProvider: KotlinScopeProvider) : FirSymbolProvider(session) {
 
     private data class SyntheticFunctionalInterfaceSymbolKey(val kind: FunctionClassKind, val arity: Int)
 
@@ -243,6 +243,10 @@ class FirBuiltinSymbolProvider(session: FirSession, val kotlinScopeProvider: Kot
 
     @FirSymbolProviderInternals
     override fun getTopLevelFunctionSymbolsTo(destination: MutableList<FirNamedFunctionSymbol>, packageFqName: FqName, name: Name) {
+        getTopLevelFunctionSymbolsToByPackageFragments(destination, packageFqName, name)
+    }
+
+    protected fun getTopLevelFunctionSymbolsToByPackageFragments(destination: MutableList<FirNamedFunctionSymbol>, packageFqName: FqName, name: Name) {
         allPackageFragments[packageFqName]?.flatMapTo(destination) {
             it.getTopLevelFunctionSymbols(name)
         }

idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/providers/FirIdeBuiltinSymbolProvider.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2010-2021 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.idea.fir.low.level.api.providers
+
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.caches.*
+import org.jetbrains.kotlin.fir.resolve.providers.FirSymbolProviderInternals
+import org.jetbrains.kotlin.fir.resolve.providers.impl.FirBuiltinSymbolProvider
+import org.jetbrains.kotlin.fir.scopes.KotlinScopeProvider
+import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
+import org.jetbrains.kotlin.name.CallableId
+import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.Name
+
+class FirIdeBuiltinSymbolProvider(
+    session: FirSession,
+    kotlinScopeProvider: KotlinScopeProvider
+) : FirBuiltinSymbolProvider(session, kotlinScopeProvider) {
+    @OptIn(ExperimentalStdlibApi::class)
+    private val functionsCache = session.firCachesFactory.createCache { callableId: CallableId ->
+        buildList {
+            getTopLevelFunctionSymbolsToByPackageFragments(this, callableId.packageName, callableId.callableName)
+        }
+    }
+
+    @OptIn(FirSymbolProviderInternals::class)
+    override fun getTopLevelCallableSymbolsTo(destination: MutableList<FirCallableSymbol<*>>, packageFqName: FqName, name: Name) {
+        // valid until FirBuiltinSymbolProvider provide property symbols
+        destination += functionsCache.getValue(CallableId(packageFqName, name))
+    }
+
+    @OptIn(FirSymbolProviderInternals::class)
+    override fun getTopLevelFunctionSymbolsTo(destination: MutableList<FirNamedFunctionSymbol>, packageFqName: FqName, name: Name) {
+        destination += functionsCache.getValue(CallableId(packageFqName, name))
+    }
+}

idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/sessions/FirIdeSessionFactory.kt

@@ -218,7 +218,7 @@ internal object FirIdeSessionFactory {
             val symbolProvider = FirCompositeSymbolProvider(
                 this,
                 listOf(
-                    FirBuiltinSymbolProvider(this, kotlinScopeProvider),
+                    FirIdeBuiltinSymbolProvider(this, kotlinScopeProvider),
                     FirCloneableSymbolProvider(this, kotlinScopeProvider),
                 )
             )