Index: include/llvm/MC/MCStreamer.h
===================================================================
--- include/llvm/MC/MCStreamer.h
+++ include/llvm/MC/MCStreamer.h
@@ -139,6 +139,7 @@
                                     StringRef StringValue = "");
   virtual void emitFPU(unsigned FPU);
   virtual void emitArch(unsigned Arch);
+  virtual void emitArchExtension(unsigned ArchExt);
   virtual void emitObjectArch(unsigned Arch);
   virtual void finishAttributeSection();
   virtual void emitInst(uint32_t Inst, char Suffix = '\0');
Index: lib/Target/ARM/ARMArchExtName.h
===================================================================
--- /dev/null
+++ lib/Target/ARM/ARMArchExtName.h
@@ -0,0 +1,26 @@
+//===-- ARMArchExtName.h - List of the ARM Extension names ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_ARM_ARMARCHEXTNAME_H
+#define LLVM_LIB_TARGET_ARM_ARMARCHEXTNAME_H
+
+namespace llvm {
+namespace ARM {
+
+enum ArchExtKind {
+  INVALID_ARCHEXT = 0
+
+#define ARM_ARCHEXT_NAME(NAME, ID) , ID
+#include "ARMArchExtName.def"
+};
+
+} // namespace ARM
+} // namespace llvm
+
+#endif
Index: lib/Target/ARM/ARMArchExtName.def
===================================================================
--- /dev/null
+++ lib/Target/ARM/ARMArchExtName.def
@@ -0,0 +1,30 @@
+//===-- ARMArchExtName.def - List of the ARM Extension names ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the list of the supported ARM Architecture Extension
+// names. These can be used to enable the extension through .arch_extension
+// attribute
+//
+//===----------------------------------------------------------------------===//
+
+// NOTE: NO INCLUDE GUARD DESIRED!
+
+#ifndef ARM_ARCHEXT_NAME
+#error "You must define ARM_ARCHEXT_NAME(NAME, ID) before including ARMArchExtName.h"
+#endif
+
+ARM_ARCHEXT_NAME("crc", CRC)
+ARM_ARCHEXT_NAME("crypto", CRYPTO)
+ARM_ARCHEXT_NAME("fp", FP)
+ARM_ARCHEXT_NAME("idiv", HWDIV)
+ARM_ARCHEXT_NAME("mp", MP)
+ARM_ARCHEXT_NAME("sec", SEC)
+ARM_ARCHEXT_NAME("virt", VIRT)
+
+#undef ARM_ARCHEXT_NAME
Index: lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
===================================================================
--- lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
+++ lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
@@ -15,6 +15,7 @@
 
 #include "ARMArchName.h"
 #include "ARMFPUName.h"
+#include "ARMArchExtName.h"
 #include "ARMRegisterInfo.h"
 #include "ARMUnwindOpAsm.h"
 #include "llvm/ADT/StringExtras.h"
@@ -105,6 +106,19 @@
   return 0;
 }
 
+static const char *GetArchExtName(unsigned ID) {
+  switch (ID) {
+  default:
+    llvm_unreachable("Unknown ARCH Extension kind");
+    break;
+#define ARM_ARCHEXT_NAME(NAME, ID)                                             \
+  case ARM::ID:                                                                \
+    return NAME;
+#include "ARMArchExtName.def"
+  }
+  return nullptr;
+}
+
 namespace {
 
 class ARMELFStreamer;
@@ -134,6 +148,7 @@
   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
                             StringRef StrinValue) override;
   void emitArch(unsigned Arch) override;
+  void emitArchExtension(unsigned ArchExt) override;
   void emitObjectArch(unsigned Arch) override;
   void emitFPU(unsigned FPU) override;
   void emitInst(uint32_t Inst, char Suffix = '\0') override;
@@ -249,6 +264,9 @@
 void ARMTargetAsmStreamer::emitArch(unsigned Arch) {
   OS << "\t.arch\t" << GetArchName(Arch) << "\n";
 }
+void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
+  OS << "\t.arch_extension\t" << GetArchExtName(ArchExt) << "\n";
+}
 void ARMTargetAsmStreamer::emitObjectArch(unsigned Arch) {
   OS << "\t.object_arch\t" << GetArchName(Arch) << '\n';
 }
Index: lib/Target/ARM/MCTargetDesc/ARMTargetStreamer.cpp
===================================================================
--- lib/Target/ARM/MCTargetDesc/ARMTargetStreamer.cpp
+++ lib/Target/ARM/MCTargetDesc/ARMTargetStreamer.cpp
@@ -63,6 +63,7 @@
                                              unsigned IntValue,
                                              StringRef StringValue) {}
 void ARMTargetStreamer::emitArch(unsigned Arch) {}
+void ARMTargetStreamer::emitArchExtension(unsigned ArchExt) {}
 void ARMTargetStreamer::emitObjectArch(unsigned Arch) {}
 void ARMTargetStreamer::emitFPU(unsigned FPU) {}
 void ARMTargetStreamer::finishAttributeSection() {}