Index: lld/trunk/test/wasm/visibility-hidden.ll
===================================================================
--- lld/trunk/test/wasm/visibility-hidden.ll
+++ lld/trunk/test/wasm/visibility-hidden.ll
@@ -2,11 +2,17 @@
 ; RUN: llc -filetype=obj %S/Inputs/hidden.ll -o %t2.o
 ; RUN: rm -f %t2.a
 ; RUN: llvm-ar rcs %t2.a %t2.o
-; RUN: wasm-ld %t.o %t2.a -o %t.wasm
-; RUN: obj2yaml %t.wasm | FileCheck %s
 
 ; Test that hidden symbols are not exported, whether pulled in from an archive
 ; or directly.
+; RUN: wasm-ld %t.o %t2.a -o %t.wasm
+; RUN: obj2yaml %t.wasm | FileCheck %s
+
+; Test that symbols with default visitiblity are not exported when
+; --no-export-default is passed.
+; RUN: wasm-ld --no-export-default %t.o %t2.a -o %t.nodef.wasm
+; RUN: obj2yaml %t.nodef.wasm | FileCheck %s -check-prefix=NO-DEFAULT
+
 
 target triple = "wasm32-unknown-unknown"
 
@@ -53,3 +59,11 @@
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           5
 ; CHECK-NEXT:   - Type:
+
+
+; NO-DEFAULT:        - Type:            EXPORT
+; NO-DEFAULT-NEXT:     Exports:
+; NO-DEFAULT-NEXT:       - Name:            memory
+; NO-DEFAULT-NEXT:         Kind:            MEMORY
+; NO-DEFAULT-NEXT:         Index:           0
+; NO-DEFAULT-NEXT:   - Type:
Index: lld/trunk/wasm/Config.h
===================================================================
--- lld/trunk/wasm/Config.h
+++ lld/trunk/wasm/Config.h
@@ -24,6 +24,7 @@
   bool Demangle;
   bool DisableVerify;
   bool ExportAll;
+  bool ExportDefault;
   bool ExportTable;
   bool GcSections;
   bool ImportMemory;
Index: lld/trunk/wasm/Driver.cpp
===================================================================
--- lld/trunk/wasm/Driver.cpp
+++ lld/trunk/wasm/Driver.cpp
@@ -373,6 +373,8 @@
   Config->DisableVerify = Args.hasArg(OPT_disable_verify);
   Config->Entry = getEntry(Args, Args.hasArg(OPT_relocatable) ? "" : "_start");
   Config->ExportAll = Args.hasArg(OPT_export_all);
+  Config->ExportDefault = Args.hasFlag(OPT_export_default,
+      OPT_no_export_default, true);
   Config->ExportTable = Args.hasArg(OPT_export_table);
   errorHandler().FatalWarnings =
       Args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false);
Index: lld/trunk/wasm/Options.td
===================================================================
--- lld/trunk/wasm/Options.td
+++ lld/trunk/wasm/Options.td
@@ -30,6 +30,10 @@
     "Demangle symbol names",
     "Do not demangle symbol names">;
 
+defm export_default: B<"export-default",
+    "Export symbols marked as 'default' visibility (default)",
+    "Do not export symbols marked as 'default' visibility">;
+
 def entry: S<"entry">, MetaVarName<"<entry>">,
   HelpText<"Name of entry point symbol">;
 
Index: lld/trunk/wasm/Symbols.cpp
===================================================================
--- lld/trunk/wasm/Symbols.cpp
+++ lld/trunk/wasm/Symbols.cpp
@@ -105,6 +105,9 @@
   if (ForceExport || Config->ExportAll)
     return true;
 
+  if (!Config->ExportDefault)
+    return false;
+
   return !isHidden();
 }