Add multi-thread to ObjcExportHeaderGenerator when processing packageFragments

KT-82436

Author: alfonsocv12

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"))

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>,
@@ -117,32 +118,42 @@ 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<MutableList<ClassDescriptor>>()
+
+        runBlocking {
+            packageFragments.forEach { packageFragment ->
+                val memberScope = packageFragment.getMemberScope()
+
+                // Keep Order
+                val inOrderCollector = mutableListOf<ClassDescriptor>()
+                classesToTranslate.add(inOrderCollector)
+
+                launch(Dispatchers.Default) {
+                    memberScope.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>()
 
-        packageFragments.forEach { packageFragment ->
-            packageFragment.getMemberScope().collectClasses(classesToTranslate)
+                launch(Dispatchers.Default) {
+                    memberScope.collectClasses(inOrderCollector)
+                }
+            }
         }
 
-        classesToTranslate.makeClassesOrderStable().forEach { translateClass(it) }
+        classesToTranslate.flatten().makeClassesOrderStable().forEach { translateClass(it) }
 
         extensions.makeCategoriesOrderStable().forEach { (classDescriptor, declarations) ->
             generateExtensions(classDescriptor, declarations)