diff --git a/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt b/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt
index aaadd72ad61..17a60736854 100644
--- a/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt
+++ b/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt
@@ -20,18 +20,19 @@ import com.intellij.openapi.Disposable
 import org.jetbrains.annotations.NotNull
 import org.jetbrains.annotations.Nullable
 import org.jetbrains.kotlin.backend.konan.*
-import org.jetbrains.kotlin.konan.util.profile
 import org.jetbrains.kotlin.cli.common.CLICompiler
 import org.jetbrains.kotlin.cli.common.CLITool
 import org.jetbrains.kotlin.cli.common.CommonCompilerPerformanceManager
 import org.jetbrains.kotlin.cli.common.ExitCode
-import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity.*
+import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity.ERROR
+import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity.WARNING
 import org.jetbrains.kotlin.cli.jvm.compiler.EnvironmentConfigFiles
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
 import org.jetbrains.kotlin.config.*
 import org.jetbrains.kotlin.konan.KonanVersion
 import org.jetbrains.kotlin.konan.file.File
 import org.jetbrains.kotlin.konan.target.CompilerOutputKind
+import org.jetbrains.kotlin.konan.util.profile
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.utils.KotlinPaths
 
@@ -172,6 +173,8 @@ class K2Native : CLICompiler<K2NativeCompilerArguments>() {
                     } else {
                         arguments.checkDependencies
                     })
+                if (arguments.friendModules != null)
+                    put(FRIEND_MODULES, arguments.friendModules!!.split(File.pathSeparator).filterNot(String::isEmpty))
             }
         }
     }
diff --git a/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt b/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt
index 6ad57e4bdc3..6bc268cada5 100644
--- a/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt
+++ b/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt
@@ -141,5 +141,11 @@ class K2NativeCompilerArguments : CommonCompilerArguments() {
     @Argument(value = "--verify_ir", description = "Verify IR")
     var verifyIr: Boolean = false
 
+    @Argument(
+            value = "-friend-modules",
+            valueDescription = "<path>",
+            description = "Paths to friend modules"
+    )
+    var friendModules: String? = null
 }
 
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfig.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfig.kt
index f0665b44207..615c081d372 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfig.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfig.kt
@@ -108,6 +108,8 @@ class KonanConfig(val project: Project, val configuration: CompilerConfiguration
 
     private val loadedDescriptors = loadLibMetadata()
 
+    internal lateinit var friends:Set<ModuleDescriptorImpl>
+
     internal val defaultNativeLibraries = 
         if (produce == CompilerOutputKind.PROGRAM) 
             File(distribution.defaultNatives(target)).listFiles.map { it.absolutePath } 
@@ -125,13 +127,20 @@ class KonanConfig(val project: Project, val configuration: CompilerConfiguration
         val specifics = configuration.get(CommonConfigurationKeys.LANGUAGE_VERSION_SETTINGS)!!
 
         val libraries = immediateLibraries.withResolvedDependencies()
+        val friendLibsSet = configuration.get(KonanConfigKeys.FRIEND_MODULES)?.map{File(it)}?.toSet()
+        val friends = mutableListOf<ModuleDescriptorImpl>()
         for (klib in libraries) {
             profile("Loading ${klib.libraryName}") {
                 // MutableModuleContext needs ModuleDescriptorImpl, rather than ModuleDescriptor.
                 val moduleDescriptor = klib.moduleDescriptor(specifics)
                 allMetadata.add(moduleDescriptor)
+                friendLibsSet?.apply {
+                    if (contains(klib.libraryFile))
+                        friends.add(moduleDescriptor)
+                }
             }
         }
+        this.friends = friends.toSet()
         return allMetadata
     }
 
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfigurationKeys.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfigurationKeys.kt
index 6a468ea317c..c5d4de97f3c 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfigurationKeys.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfigurationKeys.kt
@@ -105,6 +105,8 @@ class KonanConfigKeys {
                 = CompilerConfigurationKey.create("verify ir")
         val VERBOSE_PHASES: CompilerConfigurationKey<List<String>> 
                 = CompilerConfigurationKey.create("verbose backend phases")
+        val FRIEND_MODULES: CompilerConfigurationKey<List<String>>
+                = CompilerConfigurationKey.create<List<String>>("friend module paths")
     }
 }
 
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/TopDownAnalyzerFacadeForKonan.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/TopDownAnalyzerFacadeForKonan.kt
index af694deb8a9..5926529e28a 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/TopDownAnalyzerFacadeForKonan.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/TopDownAnalyzerFacadeForKonan.kt
@@ -39,8 +39,9 @@ object TopDownAnalyzerFacadeForKonan {
         val context = MutableModuleContextImpl(module, projectContext)
 
         if (!module.isStdlib()) {
-            context.setDependencies(listOf(module) + config.moduleDescriptors +
-                    config.getOrCreateForwardDeclarationsModule(module.builtIns, projectContext.storageManager))
+            val dependencies = listOf(module) + config.moduleDescriptors +
+                    config.getOrCreateForwardDeclarationsModule(module.builtIns, projectContext.storageManager)
+            module.setDependencies(dependencies, config.friends)
         } else {
             assert (config.moduleDescriptors.isEmpty())
             context.setDependencies(module)
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/BinaryInterface.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/BinaryInterface.kt
index 12746cda771..f024dd012ca 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/BinaryInterface.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/BinaryInterface.kt
@@ -99,6 +99,9 @@ internal tailrec fun DeclarationDescriptor.isExported(): Boolean {
         else -> null
     }
 
+    /**
+     * note: about INTERNAL - with support of friend modules we let frontend to deal with internal declarations.
+     */
     if (visibility != null && !visibility.isPublicAPI && visibility != Visibilities.INTERNAL) {
         // If the declaration is explicitly marked as non-public,
         // then it must not be accessible from other modules.
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/ContextUtils.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/ContextUtils.kt
index 9e8e1fc445d..90e38d93401 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/ContextUtils.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/ContextUtils.kt
@@ -16,23 +16,27 @@
 
 package org.jetbrains.kotlin.backend.konan.llvm
 
-import kotlinx.cinterop.*
+import kotlinx.cinterop.allocArray
+import kotlinx.cinterop.cValuesOf
+import kotlinx.cinterop.get
+import kotlinx.cinterop.memScoped
 import llvm.*
 import org.jetbrains.kotlin.backend.konan.Context
 import org.jetbrains.kotlin.backend.konan.descriptors.CurrentKonanModule
 import org.jetbrains.kotlin.backend.konan.descriptors.DeserializedKonanModule
 import org.jetbrains.kotlin.backend.konan.descriptors.LlvmSymbolOrigin
 import org.jetbrains.kotlin.backend.konan.descriptors.findPackage
-import org.jetbrains.kotlin.konan.target.KonanTarget
 import org.jetbrains.kotlin.backend.konan.hash.GlobalHash
 import org.jetbrains.kotlin.backend.konan.irasdescriptors.*
-import org.jetbrains.kotlin.backend.konan.isNativeBinary
 import org.jetbrains.kotlin.backend.konan.library.KonanLibraryReader
 import org.jetbrains.kotlin.backend.konan.library.impl.LibraryReaderImpl
 import org.jetbrains.kotlin.backend.konan.library.withResolvedDependencies
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithVisibility
+import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.ir.declarations.IrExternalPackageFragment
 import org.jetbrains.kotlin.ir.declarations.IrField
 import org.jetbrains.kotlin.ir.declarations.IrFile
+import org.jetbrains.kotlin.konan.target.KonanTarget
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import kotlin.properties.ReadOnlyProperty