Index: lld/trunk/test/wasm/export-all.ll
===================================================================
--- lld/trunk/test/wasm/export-all.ll
+++ lld/trunk/test/wasm/export-all.ll
@@ -0,0 +1,45 @@
+; RUN: llc -O0 -filetype=obj %s -o %t.o
+
+; RUN: wasm-ld -o %t.wasm %t.o
+; RUN: obj2yaml %t.wasm | FileCheck %s
+
+; RUN: wasm-ld --export-all -o %t.wasm %t.o
+; RUN: obj2yaml %t.wasm | FileCheck %s -check-prefix=EXPORT
+
+; RUN: wasm-ld --export-all --no-gc-sections -o %t.wasm %t.o
+; RUN: obj2yaml %t.wasm | FileCheck %s -check-prefix=NOGC
+
+; Verify the --export-all flag exports hidden symbols
+
+target triple = "wasm32-unknown-unknown"
+
+define hidden void @bar() local_unnamed_addr {
+entry:
+  ret void
+}
+
+define hidden void @foo() local_unnamed_addr {
+entry:
+  ret void
+}
+
+define hidden void @_start() local_unnamed_addr {
+entry:
+  call void @foo()
+  ret void
+}
+
+; CHECK:      - Type:            EXPORT
+; CHECK:         - Name:            _start
+; CHECK-NOT:     - Name:            bar
+; CHECK-NOT:     - Name:            foo
+
+; EXPORT:     - Type:            EXPORT
+; EXPORT:        - Name:            _start
+; EXPORT-NOT:    - Name:            bar
+; EXPORT:        - Name:            foo
+
+; NOGC:       - Type:            EXPORT
+; NOGC:        - Name:            _start
+; NOGC:        - Name:            bar
+; NOGC:        - Name:            foo
Index: lld/trunk/wasm/Config.h
===================================================================
--- lld/trunk/wasm/Config.h
+++ lld/trunk/wasm/Config.h
@@ -23,6 +23,7 @@
   bool CompressRelocTargets;
   bool Demangle;
   bool DisableVerify;
+  bool ExportAll;
   bool ExportTable;
   bool GcSections;
   bool ImportMemory;
Index: lld/trunk/wasm/Driver.cpp
===================================================================
--- lld/trunk/wasm/Driver.cpp
+++ lld/trunk/wasm/Driver.cpp
@@ -319,6 +319,7 @@
   Config->Demangle = Args.hasFlag(OPT_demangle, OPT_no_demangle, true);
   Config->DisableVerify = Args.hasArg(OPT_disable_verify);
   Config->Entry = getEntry(Args, Args.hasArg(OPT_relocatable) ? "" : "_start");
+  Config->ExportAll = Args.hasArg(OPT_export_all);
   Config->ExportTable = Args.hasArg(OPT_export_table);
   errorHandler().FatalWarnings =
       Args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false);
@@ -389,10 +390,6 @@
 
   Symbol *EntrySym = nullptr;
   if (!Config->Relocatable) {
-    // Can't export the SP right now because it's mutable, and mutable
-    // globals aren't yet supported in the official binary format.
-    // TODO(sbc): Remove WASM_SYMBOL_VISIBILITY_HIDDEN if/when the
-    // "mutable global" proposal is accepted.
     llvm::wasm::WasmGlobal Global;
     Global.Type = {WASM_TYPE_I32, true};
     Global.InitExpr.Value.Int32 = 0;
@@ -407,6 +404,9 @@
     WasmSym::CallCtors = Symtab->addSyntheticFunction(
         "__wasm_call_ctors", WASM_SYMBOL_VISIBILITY_HIDDEN,
         make<SyntheticFunction>(NullSignature, "__wasm_call_ctors"));
+    // TODO(sbc): Remove WASM_SYMBOL_VISIBILITY_HIDDEN when the mutable global
+    // spec proposal is implemented in all major browsers.
+    // See: https://github.com/WebAssembly/mutable-global
     WasmSym::StackPointer = Symtab->addSyntheticGlobal(
         "__stack_pointer", WASM_SYMBOL_VISIBILITY_HIDDEN, StackPointer);
     WasmSym::HeapBase = Symtab->addSyntheticDataSymbol("__heap_base", 0);
Index: lld/trunk/wasm/Options.td
===================================================================
--- lld/trunk/wasm/Options.td
+++ lld/trunk/wasm/Options.td
@@ -105,6 +105,9 @@
 defm export: Eq<"export">,
   HelpText<"Force a symbol to be exported">;
 
+def export_all: F<"export-all">,
+  HelpText<"Export all symbols (normally combined with --no-gc-sections)">;
+
 def export_table: F<"export-table">,
   HelpText<"Export function table to the environment">;
 
Index: lld/trunk/wasm/Writer.cpp
===================================================================
--- lld/trunk/wasm/Writer.cpp
+++ lld/trunk/wasm/Writer.cpp
@@ -742,7 +742,9 @@
   for (Symbol *Sym : Symtab->getSymbols()) {
     if (!Sym->isDefined())
       continue;
-    if (Sym->isHidden() || Sym->isLocal())
+    if (Sym->isHidden() && !Config->ExportAll)
+      continue;
+    if (Sym->isLocal())
       continue;
     if (!Sym->isLive())
       continue;
@@ -752,6 +754,14 @@
     if (auto *F = dyn_cast<DefinedFunction>(Sym)) {
       Export = {Name, WASM_EXTERNAL_FUNCTION, F->getFunctionIndex()};
     } else if (auto *G = dyn_cast<DefinedGlobal>(Sym)) {
+      // TODO(sbc): Remove this check once to mutable global proposal is
+      // implement in all major browsers.
+      // See: https://github.com/WebAssembly/mutable-global
+      if (G->getGlobalType()->Mutable) {
+        // Only the __stack_pointer should ever be create as mutable.
+        assert(G == WasmSym::StackPointer);
+        continue;
+      }
       Export = {Name, WASM_EXTERNAL_GLOBAL, G->getGlobalIndex()};
     } else {
       auto *D = cast<DefinedData>(Sym);