Support serializing a module's own descriptors without dependencies

The KlibMetadataSerializer used to serialize all package fragments that a module
could provide, including those coming from the module's dependencies. In order
to produce a klib from a module that is analyzed by the K2MetadataCompiler, the
serializer needs to take just the own package fragments of the module, excluding
those of the dependencies.

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/metadata/KlibMetadataMonolithicSerializer.kt

@@ -1,8 +1,6 @@
 package org.jetbrains.kotlin.backend.common.serialization.metadata
 
 import org.jetbrains.kotlin.backend.common.serialization.DescriptorTable
-import org.jetbrains.kotlin.backend.common.serialization.isExpectMember
-import org.jetbrains.kotlin.backend.common.serialization.isSerializableExpectClass
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.library.SerializedMetadata
@@ -20,15 +18,18 @@ class KlibMetadataMonolithicSerializer(
     languageVersionSettings: LanguageVersionSettings,
     metadataVersion: BinaryVersion,
     descriptorTable: DescriptorTable,
-    skipExpects: Boolean
+    skipExpects: Boolean,
-) : KlibMetadataSerializer(languageVersionSettings, metadataVersion, descriptorTable, skipExpects) {
+    includeOnlyModuleContent: Boolean = false
+) : KlibMetadataSerializer(languageVersionSettings, metadataVersion, descriptorTable, skipExpects, includeOnlyModuleContent) {
 
     private fun serializePackageFragment(fqName: FqName, module: ModuleDescriptor): List<ProtoBuf.PackageFragment> {
 
-        // TODO: ModuleDescriptor should be able to return
+        val fragments = if (includeOnlyModuleContent) {
-        // the package only with the contents of that module, without dependencies
+            module.packageFragmentProviderForModuleContentWithoutDependencies.getPackageFragments(fqName)
+        } else {
+            module.getPackage(fqName).fragments.filter { it.module == module }
+        }
 
-        val fragments = module.getPackage(fqName).fragments.filter { it.module == module }
         if (fragments.isEmpty()) return emptyList()
 
         val classifierDescriptors = DescriptorSerializer.sort(

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/metadata/KlibMetadataSerializer.kt

@@ -12,13 +12,13 @@ import org.jetbrains.kotlin.backend.common.serialization.newDescriptorUniqId
 import org.jetbrains.kotlin.config.AnalysisFlags
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.descriptors.impl.ModuleDescriptorImpl
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.library.metadata.KlibMetadataProtoBuf
 import org.jetbrains.kotlin.metadata.ProtoBuf
 import org.jetbrains.kotlin.metadata.deserialization.BinaryVersion
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
-import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
 import org.jetbrains.kotlin.serialization.DescriptorSerializer
@@ -34,7 +34,8 @@ abstract class KlibMetadataSerializer(
     val languageVersionSettings: LanguageVersionSettings,
     val metadataVersion: BinaryVersion,
     val descriptorTable: DescriptorTable,
-    val skipExpects: Boolean = false
+    val skipExpects: Boolean = false,
+    val includeOnlyModuleContent: Boolean = false
 ) {
 
     lateinit var serializerContext: SerializerContext
@@ -234,9 +235,16 @@ abstract class KlibMetadataSerializer(
     protected fun getPackagesFqNames(module: ModuleDescriptor): Set<FqName> {
         val result = mutableSetOf<FqName>()
 
+        fun getSubPackagesOfModule(fqName: FqName) =
+            if (includeOnlyModuleContent) {
+                module.packageFragmentProviderForModuleContentWithoutDependencies.getSubPackagesOf(fqName) { true }
+            } else {
+                module.getSubPackagesOf(fqName) { true }
+            }
+
         fun getSubPackages(fqName: FqName) {
             result.add(fqName)
-            module.getSubPackagesOf(fqName) { true }.forEach { getSubPackages(it) }
+            getSubPackagesOfModule(fqName).forEach { getSubPackages(it) }
         }
 
         getSubPackages(FqName.ROOT)
@@ -292,3 +300,7 @@ fun DeclarationDescriptor.extractFileId(): Int? = when (this) {
     is DeserializedPropertyDescriptor -> proto.getExtension(KlibMetadataProtoBuf.propertyFile)
     else -> null
 }
+
+internal val ModuleDescriptor.packageFragmentProviderForModuleContentWithoutDependencies: PackageFragmentProvider
+    get() = (this as? ModuleDescriptorImpl)?.packageFragmentProviderForModuleContentWithoutDependencies
+        ?: error("Can't get a module content package fragments, it's not a ${ModuleDescriptorImpl::class.simpleName}.")