diff --git a/include/clang/Basic/TargetInfo.h b/include/clang/Basic/TargetInfo.h
index 11e009c..40df9ba 100644
--- a/include/clang/Basic/TargetInfo.h
+++ b/include/clang/Basic/TargetInfo.h
@@ -40,8 +40,17 @@
 
 /// TargetCXXABI - The types of C++ ABIs for which we can generate code.
 enum TargetCXXABI {
-  CXXABI_Unknown = -1,
+  /// The generic ("Itanium") C++ ABI, documented at:
+  ///   http://www.codesourcery.com/public/cxx-abi/
   CXXABI_Itanium,
+
+  /// The ARM C++ ABI, based largely on the Itanium ABI but with
+  /// significant differences.
+  ///    http://infocenter.arm.com
+  ///                    /help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf
+  CXXABI_ARM,
+
+  /// The Visual Studio ABI.  Only scattered official documentation exists.
   CXXABI_Microsoft
 };
 
@@ -443,12 +452,22 @@
   /// setCXXABI - Use this specific C++ ABI.
   ///
   /// \return - False on error (invalid C++ ABI name).
-  virtual bool setCXXABI(const std::string &Name) {
-    CXXABI = llvm::StringSwitch<TargetCXXABI>(Name)
+  bool setCXXABI(const std::string &Name) {
+    static const TargetCXXABI Unknown = static_cast<TargetCXXABI>(-1);
+    TargetCXXABI ABI = llvm::StringSwitch<TargetCXXABI>(Name)
+      .Case("arm", CXXABI_ARM)
       .Case("itanium", CXXABI_Itanium)
       .Case("microsoft", CXXABI_Microsoft)
-      .Default(CXXABI_Unknown);
-    if (CXXABI == CXXABI_Unknown) return false;
+      .Default(Unknown);
+    if (ABI == Unknown) return false;
+    return setCXXABI(ABI);
+  }
+
+  /// setCXXABI - Set the C++ ABI to be used by this implementation.
+  ///
+  /// \return - False on error (ABI not valid on this target)
+  virtual bool setCXXABI(TargetCXXABI ABI) {
+    CXXABI = ABI;
     return true;
   }
 
diff --git a/include/clang/Basic/TargetOptions.h b/include/clang/Basic/TargetOptions.h
index b88b1f5..f3c206f 100644
--- a/include/clang/Basic/TargetOptions.h
+++ b/include/clang/Basic/TargetOptions.h
@@ -18,11 +18,6 @@
 /// TargetOptions - Options for controlling the target.
 class TargetOptions {
 public:
-
-  TargetOptions() {
-    CXXABI = "itanium";
-  }
-
   /// If given, the name of the target triple to compile for. If not given the
   /// target will be selected to match the host.
   std::string Triple;
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index ee4608b..890dfc3 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -136,13 +136,17 @@
 }
 
 CXXABI *ASTContext::createCXXABI(const TargetInfo &T) {
-  if (!LangOpts.CPlusPlus) return NULL;
+  if (!LangOpts.CPlusPlus) return 0;
+
   switch (T.getCXXABI()) {
-  default:
+  case CXXABI_ARM:
+    return CreateARMCXXABI(*this);
+  case CXXABI_Itanium:
     return CreateItaniumCXXABI(*this);
   case CXXABI_Microsoft:
     return CreateMicrosoftCXXABI(*this);
   }
+  return 0;
 }
 
 ASTContext::ASTContext(const LangOptions& LOpts, SourceManager &SM,
diff --git a/lib/AST/CXXABI.h b/lib/AST/CXXABI.h
index 8781bd7..4b38d7a 100644
--- a/lib/AST/CXXABI.h
+++ b/lib/AST/CXXABI.h
@@ -31,6 +31,7 @@
 };
 
 /// Creates an instance of a C++ ABI class.
+CXXABI *CreateARMCXXABI(ASTContext &Ctx);
 CXXABI *CreateItaniumCXXABI(ASTContext &Ctx);
 CXXABI *CreateMicrosoftCXXABI(ASTContext &Ctx);
 }
diff --git a/lib/AST/ItaniumCXXABI.cpp b/lib/AST/ItaniumCXXABI.cpp
index 0ac80ec..c3fa466 100644
--- a/lib/AST/ItaniumCXXABI.cpp
+++ b/lib/AST/ItaniumCXXABI.cpp
@@ -11,6 +11,10 @@
 // documented at:
 //  http://www.codesourcery.com/public/cxx-abi/abi.html
 //  http://www.codesourcery.com/public/cxx-abi/abi-eh.html
+//
+// It also supports the closely-related ARM C++ ABI, documented at:
+// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf
+//
 //===----------------------------------------------------------------------===//
 
 #include "CXXABI.h"
@@ -21,6 +25,7 @@
 
 namespace {
 class ItaniumCXXABI : public CXXABI {
+protected:
   ASTContext &Context;
 public:
   ItaniumCXXABI(ASTContext &Ctx) : Context(Ctx) { }
@@ -31,9 +36,17 @@
     return 1;
   }
 };
+
+class ARMCXXABI : public ItaniumCXXABI {
+public:
+  ARMCXXABI(ASTContext &Ctx) : ItaniumCXXABI(Ctx) { }
+};
 }
 
 CXXABI *clang::CreateItaniumCXXABI(ASTContext &Ctx) {
   return new ItaniumCXXABI(Ctx);
 }
 
+CXXABI *clang::CreateARMCXXABI(ASTContext &Ctx) {
+  return new ARMCXXABI(Ctx);
+}
diff --git a/lib/Basic/TargetInfo.cpp b/lib/Basic/TargetInfo.cpp
index 7c42a80..6d42883 100644
--- a/lib/Basic/TargetInfo.cpp
+++ b/lib/Basic/TargetInfo.cpp
@@ -58,6 +58,9 @@
 
   // Default to no types using fpret.
   RealTypeUsesObjCFPRet = 0;
+
+  // Default to using the Itanium ABI.
+  CXXABI = CXXABI_Itanium;
 }
 
 // Out of line virtual dtor for TargetInfo.
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 9dcb61e..cabe50a 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -1585,6 +1585,9 @@
                            "i64:64:64-f32:32:32-f64:64:64-"
                            "v64:64:64-v128:128:128-a0:0:64-n32");
     }
+
+    // ARM targets default to using the ARM C++ ABI.
+    CXXABI = CXXABI_ARM;
   }
   virtual const char *getABI() const { return ABI.c_str(); }
   virtual bool setABI(const std::string &Name) {
@@ -2631,7 +2634,7 @@
   }
 
   // Set the target C++ ABI.
-  if (!Target->setCXXABI(Opts.CXXABI)) {
+  if (!Opts.CXXABI.empty() && !Target->setCXXABI(Opts.CXXABI)) {
     Diags.Report(diag::err_target_unknown_cxxabi) << Opts.CXXABI;
     return 0;
   }
diff --git a/lib/CodeGen/CGCXXABI.h b/lib/CodeGen/CGCXXABI.h
index 0cebcb1..7df63d3 100644
--- a/lib/CodeGen/CGCXXABI.h
+++ b/lib/CodeGen/CGCXXABI.h
@@ -30,6 +30,7 @@
 };
 
 /// Creates an instance of a C++ ABI class.
+CGCXXABI *CreateARMCXXABI(CodeGenModule &CGM);
 CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM);
 CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM);
 }
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index c0df55b..2d9d573 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -91,11 +91,15 @@
 
 void CodeGenModule::createCXXABI() {
   switch (Context.Target.getCXXABI()) {
-  default:
+  case CXXABI_ARM:
+    ABI = CreateARMCXXABI(*this);
+    break;
+  case CXXABI_Itanium:
     ABI = CreateItaniumCXXABI(*this);
     break;
   case CXXABI_Microsoft:
     ABI = CreateMicrosoftCXXABI(*this);
+    break;
   }
 }
 
diff --git a/lib/CodeGen/ItaniumCXXABI.cpp b/lib/CodeGen/ItaniumCXXABI.cpp
index a613769..bd396d2 100644
--- a/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/lib/CodeGen/ItaniumCXXABI.cpp
@@ -12,6 +12,10 @@
 // documented at:
 //  http://www.codesourcery.com/public/cxx-abi/abi.html
 //  http://www.codesourcery.com/public/cxx-abi/abi-eh.html
+//
+// It also supports the closely-related ARM ABI, documented at:
+// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf
+//
 //===----------------------------------------------------------------------===//
 
 #include "CGCXXABI.h"
@@ -31,9 +35,18 @@
     return MangleCtx;
   }
 };
+
+class ARMCXXABI : public ItaniumCXXABI {
+public:
+  ARMCXXABI(CodeGen::CodeGenModule &CGM) : ItaniumCXXABI(CGM) {}
+};
 }
 
 CodeGen::CGCXXABI *CodeGen::CreateItaniumCXXABI(CodeGenModule &CGM) {
   return new ItaniumCXXABI(CGM);
 }
 
+CodeGen::CGCXXABI *CodeGen::CreateARMCXXABI(CodeGenModule &CGM) {
+  return new ARMCXXABI(CGM);
+}
+