diff --git a/lldb/source/Target/SwiftLanguageRuntimeDynamicTypeResolution.cpp b/lldb/source/Target/SwiftLanguageRuntimeDynamicTypeResolution.cpp
index 54bc00adae560..d6801f079e5fc 100644
--- a/lldb/source/Target/SwiftLanguageRuntimeDynamicTypeResolution.cpp
+++ b/lldb/source/Target/SwiftLanguageRuntimeDynamicTypeResolution.cpp
@@ -280,6 +280,20 @@ class LLDBMemoryReader : public swift::remote::MemoryReader {
   bool queryDataLayout(DataLayoutQueryType type, void *inBuffer,
                        void *outBuffer) override {
     switch (type) {
+    // FIXME: add support for case DLQ_GetPtrAuthMask:
+    case DLQ_GetObjCReservedLowBits: {
+      auto *result = static_cast<uint8_t *>(outBuffer);
+      auto &triple = m_process.GetTarget().GetArchitecture().GetTriple();
+      if (triple.isMacOSX() && triple.getArch() == llvm::Triple::x86_64) {
+        // Obj-C reserves low bit on 64-bit Intel macOS only.
+        // Other Apple platforms don't reserve this bit (even when
+        // running on x86_64-based simulators).
+        *result = 1;
+      } else {
+        *result = 0;
+      }
+      break;
+    }
     case DLQ_GetPointerSize: {
       auto result = static_cast<uint8_t *>(outBuffer);
       *result = m_process.GetAddressByteSize();
diff --git a/lldb/unittests/Symbol/TestTypeSystemSwiftTypeRef.cpp b/lldb/unittests/Symbol/TestTypeSystemSwiftTypeRef.cpp
index 19d8b54953fae..9fe332036c956 100644
--- a/lldb/unittests/Symbol/TestTypeSystemSwiftTypeRef.cpp
+++ b/lldb/unittests/Symbol/TestTypeSystemSwiftTypeRef.cpp
@@ -126,7 +126,7 @@ TEST_F(TestTypeSystemSwiftTypeRef, Function) {
     CompilerType void_void = GetCompilerType(b.Mangle(n));
     ASSERT_TRUE(void_void.IsFunctionType(nullptr));
     ASSERT_TRUE(void_void.IsFunctionPointerType());
-    ASSERT_EQ(void_void.GetNumberOfFunctionArguments(), 0);
+    ASSERT_EQ(void_void.GetNumberOfFunctionArguments(), 0UL);
   }
   {
     NodePointer n = b.GlobalType(
@@ -134,7 +134,7 @@ TEST_F(TestTypeSystemSwiftTypeRef, Function) {
                b.Node(Node::Kind::ImplConvention, "@callee_guaranteed")));
     CompilerType impl_void_void = GetCompilerType(b.Mangle(n));
     ASSERT_TRUE(impl_void_void.IsFunctionType(nullptr));
-    ASSERT_EQ(impl_void_void.GetNumberOfFunctionArguments(), 0);
+    ASSERT_EQ(impl_void_void.GetNumberOfFunctionArguments(), 0UL);
   }
   {
     NodePointer n = b.GlobalType(b.Node(
@@ -147,7 +147,7 @@ TEST_F(TestTypeSystemSwiftTypeRef, Function) {
                b.Node(Node::Kind::Tuple))));
     CompilerType impl_two_args = GetCompilerType(b.Mangle(n));
     ASSERT_TRUE(impl_two_args.IsFunctionType(nullptr));
-    ASSERT_EQ(impl_two_args.GetNumberOfFunctionArguments(), 2);
+    ASSERT_EQ(impl_two_args.GetNumberOfFunctionArguments(), 2UL);
     ASSERT_EQ(impl_two_args.GetFunctionArgumentAtIndex(0), int_type);
     ASSERT_EQ(impl_two_args.GetFunctionArgumentAtIndex(1), void_type);
     ASSERT_EQ(impl_two_args.GetFunctionArgumentTypeAtIndex(0), int_type);
@@ -167,7 +167,7 @@ TEST_F(TestTypeSystemSwiftTypeRef, Function) {
                b.Node(Node::Kind::Type, b.Node(Node::Kind::Tuple)))));
     CompilerType two_args = GetCompilerType(b.Mangle(n));
     ASSERT_TRUE(two_args.IsFunctionType(nullptr));
-    ASSERT_EQ(two_args.GetNumberOfFunctionArguments(), 2);
+    ASSERT_EQ(two_args.GetNumberOfFunctionArguments(), 2UL);
     ASSERT_EQ(two_args.GetFunctionArgumentAtIndex(0), int_type);
     ASSERT_EQ(two_args.GetFunctionArgumentAtIndex(1), void_type);
     ASSERT_EQ(two_args.GetFunctionArgumentTypeAtIndex(0), int_type);
@@ -306,7 +306,7 @@ TEST_F(TestTypeSystemSwiftTypeRef, Scalar) {
     uint32_t count = 99;
     bool is_complex = true;
     ASSERT_FALSE(int_type.IsFloatingPointType(count, is_complex));
-    ASSERT_EQ(count, 0);
+    ASSERT_EQ(count, 0UL);
     ASSERT_EQ(is_complex, false);
     bool is_signed = true;
     ASSERT_TRUE(int_type.IsIntegerType(is_signed));
@@ -318,7 +318,7 @@ TEST_F(TestTypeSystemSwiftTypeRef, Scalar) {
     uint32_t count = 99;
     bool is_complex = true;
     ASSERT_TRUE(float_type.IsFloatingPointType(count, is_complex));
-    ASSERT_EQ(count, 1);
+    ASSERT_EQ(count, 1UL);
     ASSERT_EQ(is_complex, false);
     bool is_signed = true;
     ASSERT_FALSE(float_type.IsIntegerType(is_signed));