diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmLexer.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmLexer.cpp
new file mode 100644
index 000000000000..f859d1b1c95f
--- /dev/null
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmLexer.cpp
@@ -0,0 +1,140 @@
+//===-- ARMAsmLexer.cpp - Tokenize ARM assembly to AsmTokens --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ARM.h"
+#include "ARMTargetMachine.h"
+
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringExtras.h"
+
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCParser/MCAsmLexer.h"
+#include "llvm/MC/MCParser/MCParsedAsmOperand.h"
+
+#include "llvm/Target/TargetAsmLexer.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegistry.h"
+
+#include <string>
+#include <map>
+
+using namespace llvm;
+
+namespace {
+  
+  class ARMBaseAsmLexer : public TargetAsmLexer {
+    const MCAsmInfo &AsmInfo;
+    
+    const AsmToken &lexDefinite() {
+      return getLexer()->Lex();
+    }
+    
+    AsmToken LexTokenUAL();
+  protected:
+    typedef std::map <std::string, unsigned> rmap_ty;
+    
+    rmap_ty RegisterMap;
+    
+    void InitRegisterMap(const TargetRegisterInfo *info) {
+      unsigned numRegs = info->getNumRegs();
+
+      for (unsigned i = 0; i < numRegs; ++i) {
+        const char *regName = info->getName(i);
+        if (regName)
+          RegisterMap[regName] = i;
+      }
+    }
+    
+    unsigned MatchRegisterName(StringRef Name) {
+      rmap_ty::iterator iter = RegisterMap.find(Name.str());
+      if (iter != RegisterMap.end())
+        return iter->second;
+      else
+        return 0;
+    }
+    
+    AsmToken LexToken() {
+      if (!Lexer) {
+        SetError(SMLoc(), "No MCAsmLexer installed");
+        return AsmToken(AsmToken::Error, "", 0);
+      }
+      
+      switch (AsmInfo.getAssemblerDialect()) {
+      default:
+        SetError(SMLoc(), "Unhandled dialect");
+        return AsmToken(AsmToken::Error, "", 0);
+      case 0:
+        return LexTokenUAL();
+      }
+    }
+  public:
+    ARMBaseAsmLexer(const Target &T, const MCAsmInfo &MAI)
+      : TargetAsmLexer(T), AsmInfo(MAI) {
+    }
+  };
+  
+  class ARMAsmLexer : public ARMBaseAsmLexer {
+  public:
+    ARMAsmLexer(const Target &T, const MCAsmInfo &MAI)
+      : ARMBaseAsmLexer(T, MAI) {
+      std::string tripleString("arm-unknown-unknown");
+      std::string featureString;
+      OwningPtr<const TargetMachine> 
+        targetMachine(T.createTargetMachine(tripleString, featureString));
+      InitRegisterMap(targetMachine->getRegisterInfo());
+    }
+  };
+  
+  class ThumbAsmLexer : public ARMBaseAsmLexer {
+  public:
+    ThumbAsmLexer(const Target &T, const MCAsmInfo &MAI)
+      : ARMBaseAsmLexer(T, MAI) {
+      std::string tripleString("thumb-unknown-unknown");
+      std::string featureString;
+      OwningPtr<const TargetMachine> 
+        targetMachine(T.createTargetMachine(tripleString, featureString));
+      InitRegisterMap(targetMachine->getRegisterInfo());
+    }
+  };
+}
+
+AsmToken ARMBaseAsmLexer::LexTokenUAL() {
+  const AsmToken &lexedToken = lexDefinite();
+  
+  switch (lexedToken.getKind()) {
+  default:
+    return AsmToken(lexedToken);
+  case AsmToken::Error:
+    SetError(Lexer->getErrLoc(), Lexer->getErr());
+    return AsmToken(lexedToken);
+  case AsmToken::Identifier:
+  {
+    std::string upperCase = lexedToken.getString().str();
+    std::string lowerCase = LowercaseString(upperCase);
+    StringRef lowerRef(lowerCase);
+    
+    unsigned regID = MatchRegisterName(lowerRef);
+    
+    if (regID) {
+      return AsmToken(AsmToken::Register,
+                      lexedToken.getString(),
+                      static_cast<int64_t>(regID));
+    } else {
+      return AsmToken(lexedToken);
+    }
+  }
+  }
+}
+
+extern "C" void LLVMInitializeARMAsmLexer() {
+  RegisterAsmLexer<ARMAsmLexer> X(TheARMTarget);
+  RegisterAsmLexer<ThumbAsmLexer> Y(TheThumbTarget);
+}
+
diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index cf55377bc677..bfa89c4a4696 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -812,8 +812,11 @@ bool ARMAsmParser::ParseDirectiveCode(SMLoc L) {
   return false;
 }
 
+extern "C" void LLVMInitializeARMAsmLexer();
+
 /// Force static initialization.
 extern "C" void LLVMInitializeARMAsmParser() {
   RegisterAsmParser<ARMAsmParser> X(TheARMTarget);
   RegisterAsmParser<ARMAsmParser> Y(TheThumbTarget);
+  LLVMInitializeARMAsmLexer();
 }