[Native] Export KDoc into generated native header

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

@@ -15,6 +15,8 @@ import org.jetbrains.kotlin.resolve.checkers.ExpectedActualDeclarationChecker
 import org.jetbrains.kotlin.resolve.descriptorUtil.module
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedPropertyDescriptor
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedSimpleFunctionDescriptor
+import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedClassDescriptor
+import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedClassConstructorDescriptor
 
 internal val DeclarationDescriptor.isExpectMember: Boolean
     get() = this is MemberDescriptor && this.isExpect
@@ -51,3 +53,11 @@ fun CallableMemberDescriptor.findSourceFile(): SourceFile {
         else -> TODO()
     }
 }
+
+fun DeclarationDescriptor.extractSerializedKdocString(): String? = when (this) {
+    is DeserializedClassDescriptor -> classProto.getExtension(KlibMetadataProtoBuf.classKdoc)
+    is DeserializedSimpleFunctionDescriptor -> proto.getExtension(KlibMetadataProtoBuf.functionKdoc)
+    is DeserializedPropertyDescriptor -> proto.getExtension(KlibMetadataProtoBuf.propertyKdoc)
+    is DeserializedClassConstructorDescriptor -> proto.getExtension(KlibMetadataProtoBuf.constructorKdoc)
+    else -> null
+}

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

@@ -24,9 +24,10 @@ class KlibMetadataIncrementalSerializer(
     languageVersionSettings: LanguageVersionSettings,
     metadataVersion: BinaryVersion,
     project: Project,
+    exportKDoc: Boolean,
     skipExpects: Boolean,
     allowErrorTypes: Boolean = false
-) : KlibMetadataSerializer(languageVersionSettings, metadataVersion, project, skipExpects, allowErrorTypes = allowErrorTypes) {
+) : KlibMetadataSerializer(languageVersionSettings, metadataVersion, project, exportKDoc, skipExpects, allowErrorTypes = allowErrorTypes) {
 
     fun serializePackageFragment(
         module: ModuleDescriptor,

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

@@ -24,10 +24,11 @@ class KlibMetadataMonolithicSerializer(
     languageVersionSettings: LanguageVersionSettings,
     metadataVersion: BinaryVersion,
     project: Project?,
+    exportKDoc: Boolean,
     skipExpects: Boolean,
     includeOnlyModuleContent: Boolean = false,
     allowErrorTypes: Boolean = false
-) : KlibMetadataSerializer(languageVersionSettings, metadataVersion, project, skipExpects, includeOnlyModuleContent, allowErrorTypes) {
+) : KlibMetadataSerializer(languageVersionSettings, metadataVersion, project, exportKDoc, skipExpects, includeOnlyModuleContent, allowErrorTypes) {
 
     private fun serializePackageFragment(fqName: FqName, module: ModuleDescriptor): List<ProtoBuf.PackageFragment> {
 

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

@@ -34,6 +34,7 @@ abstract class KlibMetadataSerializer(
     val languageVersionSettings: LanguageVersionSettings,
     val metadataVersion: BinaryVersion,
     val project: Project?,
+    val exportKDoc: Boolean = false,
     val skipExpects: Boolean = false,
     val includeOnlyModuleContent: Boolean = false,
     private val allowErrorTypes: Boolean
@@ -53,7 +54,8 @@ abstract class KlibMetadataSerializer(
             languageVersionSettings,
             metadataVersion,
             ApproximatingStringTable(),
-            allowErrorTypes
+            allowErrorTypes,
+            exportKDoc
         )
         return SerializerContext(
             extension,

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

@@ -18,12 +18,19 @@ import org.jetbrains.kotlin.serialization.KotlinSerializerExtensionBase
 import org.jetbrains.kotlin.serialization.StringTableImpl
 import org.jetbrains.kotlin.types.FlexibleType
 import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithSource
+import org.jetbrains.kotlin.kdoc.psi.impl.KDocTag
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtPrimaryConstructor
+import org.jetbrains.kotlin.resolve.source.getPsi
 
 class KlibMetadataSerializerExtension(
     private val languageVersionSettings: LanguageVersionSettings,
     override val metadataVersion: BinaryVersion,
     override val stringTable: StringTableImpl,
-    private val allowErrorTypes: Boolean
+    private val allowErrorTypes: Boolean,
+    private val exportKDoc: Boolean
 ) : KotlinSerializerExtensionBase(KlibMetadataSerializerProtocol) {
     override fun shouldUseTypeTable(): Boolean = true
 
@@ -47,10 +54,20 @@ class KlibMetadataSerializerExtension(
         childSerializer: DescriptorSerializer
     ) {
         descriptorFileId(descriptor)?.let { proto.setExtension(KlibMetadataProtoBuf.classFile, it) }
+        if (exportKDoc) descriptor.findKDocString()?.let { proto.setExtension(KlibMetadataProtoBuf.classKdoc, it) }
         super.serializeClass(descriptor, proto, versionRequirementTable, childSerializer)
         childSerializer.typeTable.serialize()?.let { proto.mergeTypeTable(it) }
     }
 
+    override fun serializeConstructor(
+        descriptor: ConstructorDescriptor,
+        proto: ProtoBuf.Constructor.Builder,
+        childSerializer: DescriptorSerializer
+    ) {
+        if (exportKDoc) descriptor.findKDocString()?.let { proto.setExtension(KlibMetadataProtoBuf.constructorKdoc, it) }
+        super.serializeConstructor(descriptor, proto, childSerializer)
+    }
+
     override fun serializeProperty(
         descriptor: PropertyDescriptor,
         proto: ProtoBuf.Property.Builder,
@@ -58,6 +75,7 @@ class KlibMetadataSerializerExtension(
         childSerializer: DescriptorSerializer
     ) {
         descriptorFileId(descriptor)?.let { proto.setExtension(KlibMetadataProtoBuf.propertyFile, it) }
+        if (exportKDoc) descriptor.findKDocString()?.let { proto.setExtension(KlibMetadataProtoBuf.propertyKdoc, it) }
         super.serializeProperty(descriptor, proto, versionRequirementTable, childSerializer)
     }
 
@@ -68,9 +86,23 @@ class KlibMetadataSerializerExtension(
         childSerializer: DescriptorSerializer
     ) {
         descriptorFileId(descriptor)?.let { proto.setExtension(KlibMetadataProtoBuf.functionFile, it) }
+        if (exportKDoc) descriptor.findKDocString()?.let { proto.setExtension(KlibMetadataProtoBuf.functionKdoc, it) }
         super.serializeFunction(descriptor, proto, versionRequirementTable, childSerializer)
     }
 
     override fun releaseCoroutines() =
         languageVersionSettings.supportsFeature(LanguageFeature.ReleaseCoroutines)
 }
+
+fun DeclarationDescriptorWithSource.findKDocString(): String? {
+    val psi = source.getPsi()
+    if (psi is KtDeclaration) {
+        if (psi is KtPrimaryConstructor)
+            return null  // to be rendered with class itself
+        val kdoc = psi.docComment
+        if (kdoc != null) {
+            return kdoc.getDefaultSection().parent.text
+        }
+    }
+    return null
+}