Index: libcxxabi/trunk/src/CMakeLists.txt
===================================================================
--- libcxxabi/trunk/src/CMakeLists.txt
+++ libcxxabi/trunk/src/CMakeLists.txt
@@ -206,7 +206,12 @@
 
   if(LIBCXXABI_HERMETIC_STATIC_LIBRARY)
     append_flags_if_supported(CXXABI_STATIC_LIBRARY_FLAGS -fvisibility=hidden)
-    append_flags_if_supported(CXXABI_STATIC_LIBRARY_FLAGS -fvisibility-global-new-delete-hidden)
+    # If the hermetic library doesn't define the operator new/delete functions
+    # then its code shouldn't declare them with hidden visibility.  They might
+    # actually be provided by a shared library at link time.
+    if (LIBCXXABI_ENABLE_NEW_DELETE_DEFINITIONS)
+      append_flags_if_supported(CXXABI_STATIC_LIBRARY_FLAGS -fvisibility-global-new-delete-hidden)
+    endif()
     target_compile_options(cxxabi_static PRIVATE ${CXXABI_STATIC_LIBRARY_FLAGS})
     target_compile_definitions(cxxabi_static
       PRIVATE
Index: llvm/trunk/utils/gn/secondary/libcxxabi/src/BUILD.gn
===================================================================
--- llvm/trunk/utils/gn/secondary/libcxxabi/src/BUILD.gn
+++ llvm/trunk/utils/gn/secondary/libcxxabi/src/BUILD.gn
@@ -116,7 +116,9 @@
     public = cxxabi_headers
     if (libcxxabi_hermetic_static_library) {
       cflags = [ "-fvisibility=hidden" ]
-      cflags_cc = [ "-fvisibility-global-new-delete-hidden" ]
+      if (libcxxabi_enable_new_delete_definitions) {
+        cflags_cc = [ "-fvisibility-global-new-delete-hidden" ]
+      }
       defines = [
         "_LIBCXXABI_DISABLE_VISIBILITY_ANNOTATIONS",
         "_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS",