From 9c1f23304a38748b13b653bb3bb2b0e57cc1263d Mon Sep 17 00:00:00 2001
From: Alfonso Villalobos Ulate <alfonsou@google.com>
Date: Tue, 11 Nov 2025 10:54:18 -0600
Subject: [PATCH] Add multi-thread to ObjcExportHeaderGenerator when processing
 packageFragments

KT-82436
---
 .../impl/k1/build.gradle.kts                  |  5 ++
 .../objcexport/ObjCExportHeaderGenerator.kt   | 50 +++++++++++--------
 2 files changed, 35 insertions(+), 20 deletions(-)

diff --git a/native/objcexport-header-generator/impl/k1/build.gradle.kts b/native/objcexport-header-generator/impl/k1/build.gradle.kts
index 4462d32b3cb5a..51632572a354a 100644
--- a/native/objcexport-header-generator/impl/k1/build.gradle.kts
+++ b/native/objcexport-header-generator/impl/k1/build.gradle.kts
@@ -8,7 +8,12 @@ sourceSets {
     "test" { projectDefault() }
 }
 
+repositories {
+    mavenCentral()
+}
+
 dependencies {
+    implementation(libs.kotlinx.coroutines.core)
     api(project(":native:objcexport-header-generator"))
     testImplementation(project(":compiler:cli-base"))
     implementation(project(":compiler:ir.backend.common"))
diff --git a/native/objcexport-header-generator/impl/k1/src/org/jetbrains/kotlin/backend/konan/objcexport/ObjCExportHeaderGenerator.kt b/native/objcexport-header-generator/impl/k1/src/org/jetbrains/kotlin/backend/konan/objcexport/ObjCExportHeaderGenerator.kt
index 1b60e07c1b579..ada73144b2aaf 100644
--- a/native/objcexport-header-generator/impl/k1/src/org/jetbrains/kotlin/backend/konan/objcexport/ObjCExportHeaderGenerator.kt
+++ b/native/objcexport-header-generator/impl/k1/src/org/jetbrains/kotlin/backend/konan/objcexport/ObjCExportHeaderGenerator.kt
@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.SourceFile
 import org.jetbrains.kotlin.resolve.scopes.MemberScope
+import kotlinx.coroutines.*
 
 abstract class ObjCExportHeaderGenerator @InternalKotlinNativeApi constructor(
     val moduleDescriptors: List<ModuleDescriptor>,
@@ -23,6 +24,7 @@ abstract class ObjCExportHeaderGenerator @InternalKotlinNativeApi constructor(
     val objcExportBlockExplicitParameterNames: Boolean,
     problemCollector: ObjCExportProblemCollector,
 ) {
+    private val mutex = Mutex()
     private val stubs = mutableListOf<ObjCExportStub>()
 
     private val classForwardDeclarations = linkedSetOf<ObjCClassForwardDeclaration>()
@@ -117,30 +119,38 @@ abstract class ObjCExportHeaderGenerator @InternalKotlinNativeApi constructor(
             .flatMap { it.getPackageFragments() }
             .makePackagesOrderStable()
 
-        packageFragments.forEach { packageFragment ->
-            packageFragment.getMemberScope().getContributedDescriptors()
-                .asSequence()
-                .filterIsInstance<CallableMemberDescriptor>()
-                .filter { mapper.shouldBeExposed(it) }
-                .forEach {
-                    val classDescriptor = getClassIfCategory(it)
-                    if (classDescriptor == null) {
-                        topLevel.getOrPut(it.findSourceFile(), { mutableListOf() }) += it
-                    } else {
-                        // If a class is hidden from Objective-C API then it is meaningless
-                        // to export its extensions.
-                        if (!classDescriptor.isHiddenFromObjC()) {
-                            extensions.getOrPut(classDescriptor, { mutableListOf() }) += it
+        val classesToTranslate = mutableListOf<ClassDescriptor>()
+
+        runBlocking {
+            packageFragments.forEach { packageFragment ->
+                val memberScope = packageFragment.getMemberScope()
+
+                launch(Dispatchers.Default) {
+                    memberScope.getContributedDescriptors()
+                        .asSequence()
+                        .filterIsInstance<CallableMemberDescriptor>()
+                        .filter { mapper.shouldBeExposed(it) }
+                        .forEach {
+                            val classDescriptor = getClassIfCategory(it)
+                            if (classDescriptor == null) {
+                                mutex.withLock {
+                                    topLevel.getOrPut(it.findSourceFile(), { mutableListOf() }) += it
+                                }
+                            } else {
+                                // If a class is hidden from Objective-C API then it is meaningless
+                                // to export its extensions.
+                                if (!classDescriptor.isHiddenFromObjC()) {
+                                    mutex.withLock {
+                                        extnsions.getOrPut(classDescriptor, { mutableListOf() }) += it
+                                    }
+                                }
+                            }
                         }
-                    }
                 }
+            }
         }
 
-        val classesToTranslate = mutableListOf<ClassDescriptor>()
-
-        packageFragments.forEach { packageFragment ->
-            packageFragment.getMemberScope().collectClasses(classesToTranslate)
-        }
+        memberScope.collectClasses(classesToTranslate)
 
         classesToTranslate.makeClassesOrderStable().forEach { translateClass(it) }