diff --git a/konan/konan.properties b/konan/konan.properties
index 0f285ede650..00adb172680 100644
--- a/konan/konan.properties
+++ b/konan/konan.properties
@@ -35,10 +35,10 @@ llvmVersion = 5.0.0
 
 # Mac OS X.
 llvmHome.macos_x64 = clang-llvm-5.0.0-darwin-macos
-targetToolchain.macos_x64 = target-toolchain-5-macos_x64
+targetToolchain.macos_x64 = target-toolchain-6-macos_x64
 
 arch.macos_x64 = x86_64
-targetSysRoot.macos_x64 = target-sysroot-5-macos_x64
+targetSysRoot.macos_x64 = target-sysroot-6-macos_x64
 libffiDir.macos_x64 = libffi-3.2.1-2-darwin-macos
 llvmLtoFlags.macos_x64 =
 llvmLtoOptFlags.macos_x64 = -O3 -function-sections
@@ -56,24 +56,24 @@ dependencies.macos_x64 = \
     libffi-3.2.1-2-darwin-macos \
     clang-llvm-5.0.0-darwin-macos
 
-target-sysroot-5-macos_x64.default = \
+target-sysroot-6-macos_x64.default = \
   remote:internal
 
-target-toolchain-5-macos_x64.default = \
+target-toolchain-6-macos_x64.default = \
   remote:internal
 
 # Apple iOS.
-targetToolchain.macos_x64-ios_arm64 = target-toolchain-5-macos_x64
+targetToolchain.macos_x64-ios_arm64 = target-toolchain-6-macos_x64
 dependencies.macos_x64-ios_arm64 = \
   libffi-3.2.1-2-darwin-ios \
   clang-llvm-5.0.0-darwin-macos
 
-target-sysroot-5-ios_arm64.default = \
+target-sysroot-6-ios_arm64.default = \
   remote:internal
 
 arch.ios_arm64 = arm64
 entrySelector.ios_arm64 = -alias _Konan_main _main
-targetSysRoot.ios_arm64 = target-sysroot-5-ios_arm64
+targetSysRoot.ios_arm64 = target-sysroot-6-ios_arm64
 libffiDir.ios_arm64 = libffi-3.2.1-2-darwin-ios
 llvmLtoFlags.ios_arm64 =
 llvmLtoOptFlags.ios_arm64 = -O3 -function-sections
@@ -88,17 +88,17 @@ osVersionMinFlagClang.ios_arm64 = -miphoneos-version-min
 osVersionMin.ios_arm64 = 8.0
 
 #  Apple iOS simulator.
-targetToolchain.macos_x64-ios_x64 = target-toolchain-5-macos_x64
+targetToolchain.macos_x64-ios_x64 = target-toolchain-6-macos_x64
 dependencies.macos_x64-ios_x64 = \
   libffi-3.2.1-1-darwin-ios_sim \
   clang-llvm-5.0.0-darwin-macos
 
-target-sysroot-5-ios_x64.default = \
+target-sysroot-6-ios_x64.default = \
   remote:internal
 
 arch.ios_x64 = x86_64
 entrySelector.ios_x64 = -alias _Konan_main _main
-targetSysRoot.ios_x64 = target-sysroot-5-ios_x64
+targetSysRoot.ios_x64 = target-sysroot-6-ios_x64
 libffiDir.ios_x64 = libffi-3.2.1-1-darwin-ios_sim
 llvmLtoFlags.ios_x64 =
 llvmLtoOptFlags.ios_x64 = -O3 -function-sections
diff --git a/platformLibs/src/platform/ios/ClassKit.def b/platformLibs/src/platform/ios/ClassKit.def
new file mode 100644
index 00000000000..371dee66cdf
--- /dev/null
+++ b/platformLibs/src/platform/ios/ClassKit.def
@@ -0,0 +1,9 @@
+depends = CoreFoundation Foundation darwin posix
+language = Objective-C
+package = platform.ClassKit
+headers = ClassKit/ClassKit.h
+
+headerFilter = ClassKit/**
+
+compilerOpts = -framework ClassKit
+linkerOpts = -framework ClassKit
diff --git a/platformLibs/src/platform/ios/CoreML.def b/platformLibs/src/platform/ios/CoreML.def
new file mode 100644
index 00000000000..08d5fefaf97
--- /dev/null
+++ b/platformLibs/src/platform/ios/CoreML.def
@@ -0,0 +1,9 @@
+depends = CoreVideo CoreFoundation Foundation darwin posix
+language = Objective-C
+package = platform.CoreML
+headers = CoreML/CoreML.h
+
+headerFilter = CoreML/**
+
+compilerOpts = -framework CoreML
+linkerOpts = -framework CoreML
diff --git a/platformLibs/src/platform/osx/CoreML.def b/platformLibs/src/platform/osx/CoreML.def
new file mode 100644
index 00000000000..08d5fefaf97
--- /dev/null
+++ b/platformLibs/src/platform/osx/CoreML.def
@@ -0,0 +1,9 @@
+depends = CoreVideo CoreFoundation Foundation darwin posix
+language = Objective-C
+package = platform.CoreML
+headers = CoreML/CoreML.h
+
+headerFilter = CoreML/**
+
+compilerOpts = -framework CoreML
+linkerOpts = -framework CoreML
diff --git a/runtime/src/main/kotlin/kotlin/test/Assertions.kt b/runtime/src/main/kotlin/kotlin/test/Assertions.kt
index 2477eda0ef7..f8f3d254df8 100644
--- a/runtime/src/main/kotlin/kotlin/test/Assertions.kt
+++ b/runtime/src/main/kotlin/kotlin/test/Assertions.kt
@@ -61,6 +61,16 @@ fun <@OnlyInputTypes T> assertNotEquals(illegal: T, actual: T, message: String?
     asserter.assertNotEquals(message, illegal, actual)
 }
 
+/** Asserts that [expected] is the same instance as [actual], with an optional [message]. */
+fun <@OnlyInputTypes T> assertSame(expected: T, actual: T, message: String? = null) {
+    asserter.assertSame(message, expected, actual)
+}
+
+/** Asserts that [actual] is not the same instance as [illegal], with an optional [message]. */
+fun <@OnlyInputTypes T> assertNotSame(illegal: T, actual: T, message: String? = null) {
+    asserter.assertNotSame(message, illegal, actual)
+}
+
 /** Asserts that the [actual] value is not `null`, with an optional [message]. */
 fun <T : Any> assertNotNull(actual: T?, message: String? = null): T {
     asserter.assertNotNull(message, actual)
@@ -203,6 +213,24 @@ interface Asserter {
         assertTrue({ messagePrefix(message) + "Illegal value: <$actual>." }, actual != illegal)
     }
 
+    /**
+     * Asserts that the specified values are the same instance.
+     *
+     * @param message the message to report if the assertion fails.
+     */
+    fun assertSame(message: String?, expected: Any?, actual: Any?): Unit {
+        assertTrue({ messagePrefix(message) + "Expected <$expected>, actual <$actual> is not same." }, actual === expected)
+    }
+
+    /**
+     * Asserts that the specified values are not the same instance.
+     *
+     * @param message the message to report if the assertion fails.
+     */
+    fun assertNotSame(message: String?, illegal: Any?, actual: Any?): Unit {
+        assertTrue({ messagePrefix(message) + "Expected not same as <$actual>." }, actual !== illegal)
+    }
+
     /**
      * Asserts that the specified value is `null`.
      *
diff --git a/shared/src/main/kotlin/org/jetbrains/kotlin/konan/target/KonanProperties.kt b/shared/src/main/kotlin/org/jetbrains/kotlin/konan/target/KonanProperties.kt
index b912da8e48c..2de7fa8ba56 100644
--- a/shared/src/main/kotlin/org/jetbrains/kotlin/konan/target/KonanProperties.kt
+++ b/shared/src/main/kotlin/org/jetbrains/kotlin/konan/target/KonanProperties.kt
@@ -67,7 +67,7 @@ fun Properties.keepOnlyDefaultProfiles() {
     // Force build to use only 'default' profile:
     this.setProperty(DEPENDENCY_PROFILES_KEY, "default")
     // Force build to use fixed Xcode version:
-    this.setProperty("useFixedXcodeVersion", "9.3.1")
+    this.setProperty("useFixedXcodeVersion", "9.4")
     // TODO: it actually affects only resolution made in :dependencies,
     // that's why we assume that 'default' profile comes first (and check this above).
 }
diff --git a/tools/scripts/update_xcode.sh b/tools/scripts/update_xcode.sh
index 68c493f72be..0304db7fdf1 100755
--- a/tools/scripts/update_xcode.sh
+++ b/tools/scripts/update_xcode.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-KONAN_TOOLCHAIN_VERSION=5
+KONAN_TOOLCHAIN_VERSION=6
 SDKS="macosx iphoneos iphonesimulator watchos watchsimulator"
 TARBALL_macosx=target-sysroot-$KONAN_TOOLCHAIN_VERSION-macos_x64
 TARBALL_iphoneos=target-sysroot-$KONAN_TOOLCHAIN_VERSION-ios_arm64
@@ -24,4 +24,4 @@ t=`dirname $t`
 t=`grealpath $t/../..`
 tarball=$TARBALL_xcode
 echo "Packing toolchain $OUT/$tarball.tar.gz..."
-$SHELL -c "tar czf $OUT/$tarball.tar.gz -C $t -s '/^\./$tarball/'  ."
\ No newline at end of file
+$SHELL -c "tar czf $OUT/$tarball.tar.gz -C $t -s '/^\./$tarball/'  ."