Index: ELF/Config.h
===================================================================
--- ELF/Config.h
+++ ELF/Config.h
@@ -35,12 +35,17 @@
 
 enum class UnresolvedPolicy { NoUndef, Error, Warn, Ignore };
 
+struct SymbolVersion {
+  llvm::StringRef Name;
+  bool IsExternCpp;
+};
+
 // This struct contains symbols version definition that
 // can be found in version script if it is used for link.
 struct Version {
   Version(llvm::StringRef Name) : Name(Name) {}
   llvm::StringRef Name;
-  std::vector<llvm::StringRef> Globals;
+  std::vector<SymbolVersion> Globals;
   size_t NameOff; // Offset in string table.
 };
 
@@ -67,7 +72,7 @@
   std::vector<llvm::StringRef> DynamicList;
   std::vector<llvm::StringRef> SearchPaths;
   std::vector<llvm::StringRef> Undefined;
-  std::vector<llvm::StringRef> VersionScriptGlobals;
+  std::vector<SymbolVersion> VersionScriptGlobals;
   std::vector<uint8_t> BuildIdVector;
   bool AllowMultipleDefinition;
   bool AsNeeded = false;
Index: ELF/SymbolListFile.cpp
===================================================================
--- ELF/SymbolListFile.cpp
+++ ELF/SymbolListFile.cpp
@@ -77,6 +77,7 @@
   void run();
 
 private:
+  void parseExtern(std::vector<SymbolVersion> *Globals);
   void parseVersion(StringRef Version);
   void parseLocal();
   void parseVersionSymbols(StringRef Version);
@@ -112,21 +113,38 @@
   Config->VersionScriptGlobalByDefault = false;
 }
 
+void VersionScriptParser::parseExtern(std::vector<SymbolVersion> *Globals) {
+  expect("extern");
+  expect("C++");
+  expect("{");
+
+  for (;;) {
+    if (peek() == "}" || Error)
+      break;
+    Globals->push_back({next(), true});
+    expect(";");
+  }
+
+  expect("}");
+  expect(";");
+}
+
 void VersionScriptParser::parseVersionSymbols(StringRef Version) {
-  std::vector<StringRef> *Globals;
+  std::vector<SymbolVersion> *Globals;
   if (Version.empty())
     Globals = &Config->VersionScriptGlobals;
   else
     Globals = &Config->SymbolVersions.back().Globals;
 
   for (;;) {
+    if (peek() == "extern")
+      parseExtern(Globals);
+
     StringRef Cur = peek();
-    if (Cur == "extern")
-      setError("extern keyword is not supported");
     if (Cur == "}" || Cur == "local:" || Error)
       return;
     next();
-    Globals->push_back(Cur);
+    Globals->push_back({Cur, false});
     expect(";");
   }
 }
Index: ELF/SymbolTable.cpp
===================================================================
--- ELF/SymbolTable.cpp
+++ ELF/SymbolTable.cpp
@@ -242,8 +242,9 @@
 template <typename ELFT>
 std::string SymbolTable<ELFT>::conflictMsg(SymbolBody *Existing,
                                            InputFile *NewFile) {
-  StringRef Sym = Existing->getName();
-  return demangle(Sym) + " in " + getFilename(Existing->getSourceFile<ELFT>()) +
+  std::string Name =
+      Config->Demangle ? demangle(Existing->getName()) : Existing->getName();
+  return Name + " in " + getFilename(Existing->getSourceFile<ELFT>()) +
          " and " + getFilename(NewFile);
 }
 
@@ -556,6 +557,13 @@
   return S.find_first_of("?*") != StringRef::npos;
 }
 
+static void overrideSymbolVersion(Symbol *Sym, StringRef Entry,
+                                  uint16_t Version) {
+  if (Sym->VersionId != VER_NDX_GLOBAL && Sym->VersionId != VER_NDX_LOCAL)
+    warning("duplicate symbol " + Entry + " in version script");
+  Sym->VersionId = Version;
+}
+
 // This function processes the --version-script option by marking all global
 // symbols with the VersionScriptGlobal flag, which acts as a filter on the
 // dynamic symbol table.
@@ -563,8 +571,8 @@
   // If version script does not contain versions declarations,
   // we just should mark global symbols.
   if (!Config->VersionScriptGlobals.empty()) {
-    for (StringRef S : Config->VersionScriptGlobals)
-      if (SymbolBody *B = find(S))
+    for (SymbolVersion &Sym : Config->VersionScriptGlobals)
+      if (SymbolBody *B = find(Sym.Name))
         B->symbol()->VersionId = VER_NDX_GLOBAL;
     return;
   }
@@ -576,37 +584,58 @@
   // assign version references for each symbol.
   // Current rules are:
   // * If there is an exact match for the mangled name, we use it.
+  // * Otherwise, we look for an extern C++ exact match.
   // * Otherwise, we look through the wildcard patterns. We look through the
   //   version tags in reverse order. We use the first match we find (the last
   //   matching version tag in the file).
+
+  // Handle exact matches and build a map of demangled externs for
+  // quick search during next step.
+  llvm::DenseMap<StringRef, size_t> DemangledExterns;
   for (size_t I = 0, E = Config->SymbolVersions.size(); I < E; ++I) {
     Version &V = Config->SymbolVersions[I];
-    for (StringRef Name : V.Globals) {
-      if (hasWildcard(Name))
+    for (SymbolVersion Sym : V.Globals) {
+      if (hasWildcard(Sym.Name))
+        continue;
+
+      if (Sym.IsExternCpp) {
+        size_t &Ver = DemangledExterns[Sym.Name];
+        if (Ver != 0)
+          warning("duplicate symbol " + Sym.Name + " in version script");
+        Ver = I + 2;
         continue;
+      }
 
-      SymbolBody *B = find(Name);
+      SymbolBody *B = find(Sym.Name);
       if (!B || B->isUndefined()) {
         if (Config->NoUndefinedVersion)
           error("version script assignment of " + V.Name + " to symbol " +
-                Name + " failed: symbol not defined");
+                Sym.Name + " failed: symbol not defined");
         continue;
       }
 
-      if (B->symbol()->VersionId != VER_NDX_GLOBAL &&
-          B->symbol()->VersionId != VER_NDX_LOCAL)
-        warning("duplicate symbol " + Name + " in version script");
-      B->symbol()->VersionId = I + 2;
+      overrideSymbolVersion(B->symbol(), Sym.Name, I + 2);
+    }
+  }
+
+  // Handle externs.
+  if (!DemangledExterns.empty()) {
+    for (auto I = Symtab.begin(); I != Symtab.end(); ++I) {
+      auto E = DemangledExterns.find(demangle(I->first.Val));
+      if (E == DemangledExterns.end())
+        continue;
+      overrideSymbolVersion(SymVector[I->second], E->first, E->second);
     }
   }
 
+  // Handle wildcards.
   for (size_t I = Config->SymbolVersions.size() - 1; I != (size_t)-1; --I) {
     Version &V = Config->SymbolVersions[I];
-    for (StringRef Name : V.Globals) {
-      if (!hasWildcard(Name))
+    for (SymbolVersion Sym : V.Globals) {
+      if (!hasWildcard(Sym.Name))
         continue;
 
-      for (SymbolBody *B : findAll(Name))
+      for (SymbolBody *B : findAll(Sym.Name))
         if (B->symbol()->VersionId == VER_NDX_GLOBAL ||
             B->symbol()->VersionId == VER_NDX_LOCAL)
           B->symbol()->VersionId = I + 2;
Index: ELF/Symbols.cpp
===================================================================
--- ELF/Symbols.cpp
+++ ELF/Symbols.cpp
@@ -251,9 +251,6 @@
 #if !defined(HAVE_CXXABI_H)
   return Name;
 #else
-  if (!Config->Demangle)
-    return Name;
-
   // __cxa_demangle can be used to demangle strings other than symbol
   // names which do not necessarily start with "_Z". Name can be
   // either a C or C++ symbol. Don't call __cxa_demangle if the name
Index: test/ELF/version-script-err.s
===================================================================
--- test/ELF/version-script-err.s
+++ test/ELF/version-script-err.s
@@ -8,8 +8,3 @@
 // RUN: not ld.lld --version-script %terr1.script -shared %t.o -o %t.so 2>&1 | \
 // RUN:   FileCheck -check-prefix=ERR1 %s
 // ERR1: unclosed quote
-
-// RUN: echo "VERSION { extern "C++" {}; }; " > %terr2.script
-// RUN: not ld.lld --version-script %terr2.script -shared %t.o -o %t.so 2>&1 | \
-// RUN:   FileCheck -check-prefix=ERR2 %s
-// ERR2: extern keyword is not supported
Index: test/ELF/version-script-extern.s
===================================================================
--- test/ELF/version-script-extern.s
+++ test/ELF/version-script-extern.s
@@ -0,0 +1,98 @@
+# REQUIRES: x86
+# XFAIL: win32
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: echo "LIBSAMPLE_1.0 { \
+# RUN:   global:             \
+# RUN:      extern "C++" {   \
+# RUN:         \"foo()\";    \
+# RUN:         \"zed()\";    \
+# RUN:   };                  \
+# RUN: };                    \
+# RUN: LIBSAMPLE_2.0 {       \
+# RUN:   global:             \
+# RUN:     extern "C++" {    \
+# RUN:       \"bar()\";      \
+# RUN:   };                  \
+# RUN: }; " > %t.script
+# RUN: ld.lld --version-script %t.script -shared %t.o -o %t.so
+# RUN: llvm-readobj -V -dyn-symbols %t.so | FileCheck --check-prefix=DSO %s
+
+# DSO:      DynamicSymbols [
+# DSO-NEXT:    Symbol {
+# DSO-NEXT:      Name: @
+# DSO-NEXT:      Value: 0x0
+# DSO-NEXT:      Size: 0
+# DSO-NEXT:      Binding: Local
+# DSO-NEXT:      Type: None
+# DSO-NEXT:      Other: 0
+# DSO-NEXT:      Section: Undefined
+# DSO-NEXT:    }
+# DSO-NEXT:    Symbol {
+# DSO-NEXT:      Name: _Z3barv@@LIBSAMPLE_2.0
+# DSO-NEXT:      Value: 0x1001
+# DSO-NEXT:      Size: 0
+# DSO-NEXT:      Binding: Global
+# DSO-NEXT:      Type: Function
+# DSO-NEXT:      Other: 0
+# DSO-NEXT:      Section: .text
+# DSO-NEXT:    }
+# DSO-NEXT:    Symbol {
+# DSO-NEXT:      Name: _Z3foov@@LIBSAMPLE_1.0
+# DSO-NEXT:      Value: 0x1000
+# DSO-NEXT:      Size: 0
+# DSO-NEXT:      Binding: Global
+# DSO-NEXT:      Type: Function
+# DSO-NEXT:      Other: 0
+# DSO-NEXT:      Section: .text
+# DSO-NEXT:    }
+# DSO-NEXT:    Symbol {
+# DSO-NEXT:      Name: _Z3zedv@@LIBSAMPLE_1.0
+# DSO-NEXT:      Value: 0x1002
+# DSO-NEXT:      Size: 0
+# DSO-NEXT:      Binding: Global (0x1)
+# DSO-NEXT:      Type: Function (0x2)
+# DSO-NEXT:      Other: 0
+# DSO-NEXT:      Section: .text (0x6)
+# DSO-NEXT:    }
+# DSO-NEXT:  ]
+# DSO-NEXT:  Version symbols {
+# DSO-NEXT:    Section Name: .gnu.version
+# DSO-NEXT:    Address: 0x228
+# DSO-NEXT:    Offset: 0x228
+# DSO-NEXT:    Link: 1
+# DSO-NEXT:    Symbols [
+# DSO-NEXT:      Symbol {
+# DSO-NEXT:        Version: 0
+# DSO-NEXT:        Name: @
+# DSO-NEXT:      }
+# DSO-NEXT:      Symbol {
+# DSO-NEXT:        Version: 3
+# DSO-NEXT:        Name: _Z3barv@@LIBSAMPLE_2.0
+# DSO-NEXT:      }
+# DSO-NEXT:      Symbol {
+# DSO-NEXT:        Version: 2
+# DSO-NEXT:        Name: _Z3foov@@LIBSAMPLE_1.0
+# DSO-NEXT:      }
+# DSO-NEXT:      Symbol {
+# DSO-NEXT:        Version: 2
+# DSO-NEXT:        Name: _Z3zedv@@LIBSAMPLE_1.0
+# DSO-NEXT:      }
+# DSO-NEXT:    ]
+# DSO-NEXT:  }
+
+.text
+.globl _Z3foov
+.type _Z3foov,@function
+_Z3foov:
+retq
+
+.globl _Z3barv
+.type _Z3barv,@function
+_Z3barv:
+retq
+
+.globl _Z3zedv
+.type _Z3zedv,@function
+_Z3zedv:
+retq