diff --git a/runtime/parsed_options.cc b/runtime/parsed_options.cc
index 5f350bf..d241ebe 100644
--- a/runtime/parsed_options.cc
+++ b/runtime/parsed_options.cc
@@ -38,7 +38,7 @@
 #include "cmdline_parser.h"
 #include "runtime_options.h"
 
-namespace art {
+namespace art HIDDEN {
 
 using MemoryKiB = Memory<1024>;
 
diff --git a/runtime/parsed_options.h b/runtime/parsed_options.h
index 00e0a97..527304d 100644
--- a/runtime/parsed_options.h
+++ b/runtime/parsed_options.h
@@ -24,13 +24,14 @@
 #include <jni.h>
 
 #include "arch/instruction_set.h"
+#include "base/macros.h"
 #include "gc/collector_type.h"
 #include "gc/space/large_object_space.h"
 // #include "jit/profile_saver_options.h"
 #include "runtime_globals.h"
 #include "runtime_options.h"
 
-namespace art {
+namespace art HIDDEN {
 
 class CompilerCallbacks;
 class DexFile;
diff --git a/runtime/parsed_options_test.cc b/runtime/parsed_options_test.cc
index 3d45da5..973adb5 100644
--- a/runtime/parsed_options_test.cc
+++ b/runtime/parsed_options_test.cc
@@ -21,7 +21,7 @@
 #include "arch/instruction_set.h"
 #include "base/common_art_test.h"
 
-namespace art {
+namespace art HIDDEN {
 
 class ParsedOptionsTest : public CommonArtTest {
  public:
diff --git a/runtime/plugin.cc b/runtime/plugin.cc
index 6b9e008..29ac7a6 100644
--- a/runtime/plugin.cc
+++ b/runtime/plugin.cc
@@ -23,7 +23,7 @@
 #include "base/mutex.h"
 #include "thread-current-inl.h"
 
-namespace art {
+namespace art HIDDEN {
 
 using android::base::StringPrintf;
 
diff --git a/runtime/plugin.h b/runtime/plugin.h
index 4885b2e..6164a33 100644
--- a/runtime/plugin.h
+++ b/runtime/plugin.h
@@ -21,7 +21,9 @@
 
 #include <android-base/logging.h>
 
-namespace art {
+#include "base/macros.h"
+
+namespace art HIDDEN {
 
 // This function is loaded from the plugin (if present) and called during runtime initialization.
 // By the time this has been called the runtime has been fully initialized but not other native
diff --git a/runtime/prebuilt_tools_test.cc b/runtime/prebuilt_tools_test.cc
index e05a8e4..a86cf74 100644
--- a/runtime/prebuilt_tools_test.cc
+++ b/runtime/prebuilt_tools_test.cc
@@ -20,7 +20,7 @@
 
 #include "gtest/gtest.h"
 
-namespace art {
+namespace art HIDDEN {
 
 // Run the tests only on host.
 #ifndef ART_TARGET_ANDROID
diff --git a/runtime/process_state.h b/runtime/process_state.h
index aee200a..94f8bd9 100644
--- a/runtime/process_state.h
+++ b/runtime/process_state.h
@@ -17,7 +17,9 @@
 #ifndef ART_RUNTIME_PROCESS_STATE_H_
 #define ART_RUNTIME_PROCESS_STATE_H_
 
-namespace art {
+#include "base/macros.h"
+
+namespace art HIDDEN {
 
 // The process state passed in from the activity manager, used to determine when to do trimming
 // and compaction.
diff --git a/runtime/proxy_test.cc b/runtime/proxy_test.cc
index ac8ec56..c57b3d4 100644
--- a/runtime/proxy_test.cc
+++ b/runtime/proxy_test.cc
@@ -25,7 +25,7 @@
 #include "scoped_thread_state_change-inl.h"
 #include "well_known_classes.h"
 
-namespace art {
+namespace art HIDDEN {
 namespace proxy_test {
 
 class ProxyTest : public CommonRuntimeTest {
diff --git a/runtime/proxy_test.h b/runtime/proxy_test.h
index 9a01441..8c69a2e 100644
--- a/runtime/proxy_test.h
+++ b/runtime/proxy_test.h
@@ -21,13 +21,14 @@
 #include <vector>
 
 #include "art_method-inl.h"
+#include "base/macros.h"
 #include "class_linker-inl.h"
 #include "class_root-inl.h"
 #include "mirror/class-inl.h"
 #include "mirror/method.h"
 #include "obj_ptr-inl.h"
 
-namespace art {
+namespace art HIDDEN {
 namespace proxy_test {
 
 // Generate a proxy class with the given name and interfaces. This is a simplification from what