Index: lib/Driver/ToolChains/Gnu.cpp
===================================================================
--- lib/Driver/ToolChains/Gnu.cpp
+++ lib/Driver/ToolChains/Gnu.cpp
@@ -535,6 +535,19 @@
   C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
 }
 
+
+// On Arm and AArch64 the endianness of the output file is determined by
+// the target and can be overridden by the pseudo-target flags
+// '-mlittle-endian'/'-EL' and '-mbig-endian'/'-EB'. Return the assembler
+// flag we need to ensure the correct endianness of the assembler output.
+static const char* GetEndianArg(bool IsBigEndian, const ArgList &Args) {
+  if (Arg *A = Args.getLastArg(options::OPT_mlittle_endian,
+                               options::OPT_mbig_endian)) {
+      IsBigEndian = !A->getOption().matches(options::OPT_mlittle_endian);
+  }
+  return (IsBigEndian) ? "-EB" : "-EL";
+}
+
 void tools::gnutools::Assembler::ConstructJob(Compilation &C,
                                               const JobAction &JA,
                                               const InputInfo &Output,
@@ -638,6 +651,9 @@
   case llvm::Triple::thumb:
   case llvm::Triple::thumbeb: {
     const llvm::Triple &Triple2 = getToolChain().getTriple();
+    bool IsBigEndian = Triple2.getArch() == llvm::Triple::armeb ||
+                       Triple2.getArch() == llvm::Triple::thumbeb;
+    CmdArgs.push_back(GetEndianArg(IsBigEndian, Args));
     switch (Triple2.getSubArch()) {
     case llvm::Triple::ARMSubArch_v7:
       CmdArgs.push_back("-mfpu=neon");
@@ -670,6 +686,9 @@
   }
   case llvm::Triple::aarch64:
   case llvm::Triple::aarch64_be: {
+    bool IsBigEndian =
+        getToolChain().getTriple().getArch() == llvm::Triple::aarch64_be;
+    CmdArgs.push_back(GetEndianArg(IsBigEndian, Args));
     Args.AddLastArg(CmdArgs, options::OPT_march_EQ);
     normalizeCPUNamesForAssembler(Args, CmdArgs);
 
Index: test/Driver/linux-as.c
===================================================================
--- test/Driver/linux-as.c
+++ test/Driver/linux-as.c
@@ -3,129 +3,140 @@
 // RUN: %clang -target arm-linux -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM %s
-// CHECK-ARM: as{{(.exe)?}}" "-mfloat-abi=soft"
+// CHECK-ARM: as{{(.exe)?}}" "-EL" "-mfloat-abi=soft"
 //
 // RUN: %clang -target arm-linux -mcpu=cortex-a8 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-MCPU %s
-// CHECK-ARM-MCPU: as{{(.exe)?}}" "-mfloat-abi=soft" "-mcpu=cortex-a8"
+// CHECK-ARM-MCPU: as{{(.exe)?}}" "-EL" "-mfloat-abi=soft" "-mcpu=cortex-a8"
 //
 // RUN: %clang -target arm-linux -mfpu=neon -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-MFPU %s
-// CHECK-ARM-MFPU: as{{(.exe)?}}" "-mfloat-abi=soft" "-mfpu=neon"
+// CHECK-ARM-MFPU: as{{(.exe)?}}" "-EL" "-mfloat-abi=soft" "-mfpu=neon"
 //
 // RUN: %clang -target arm-linux -march=armv7-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-MARCH %s
-// CHECK-ARM-MARCH: as{{(.exe)?}}" "-mfloat-abi=soft" "-march=armv7-a"
+// CHECK-ARM-MARCH: as{{(.exe)?}}" "-EL" "-mfloat-abi=soft" "-march=armv7-a"
+//
+// RUN: %clang -target armeb-linux -mlittle-endian -mcpu=cortex-a8 -mfpu=neon -march=armv7-a -### \
+// RUN:   -no-integrated-as -c %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM-ALL %s
+// CHECK-ARM-ALL: as{{(.exe)?}}" "-EL" "-mfloat-abi=soft" "-march=armv7-a" "-mcpu=cortex-a8" "-mfpu=neon"
 //
 // RUN: %clang -target arm-linux -mcpu=cortex-a8 -mfpu=neon -march=armv7-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-ALL %s
-// CHECK-ARM-ALL: as{{(.exe)?}}" "-mfloat-abi=soft" "-march=armv7-a" "-mcpu=cortex-a8" "-mfpu=neon"
 //
-// RUN: %clang -target arm-linux -mcpu=cortex-a8 -mfpu=neon -march=armebv7-a -### \
+// RUN: %clang -target armeb-linux -mcpu=cortex-a8 -mfpu=neon -march=armebv7-a -### \
+// RUN:   -no-integrated-as -c %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARMEB-ALL %s
+// CHECK-ARMEB-ALL: as{{(.exe)?}}" "-EB" "-mfloat-abi=soft" "-march=armebv7-a" "-mcpu=cortex-a8" "-mfpu=neon"
+//
+// RUN: %clang -target arm-linux -mcpu=cortex-a8 -mfpu=neon -march=armebv7-a -mbig-endian -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARMEB-ALL %s
-// CHECK-ARMEB-ALL: as{{(.exe)?}}" "-mfloat-abi=soft" "-march=armebv7-a" "-mcpu=cortex-a8" "-mfpu=neon"
 //
 // RUN: %clang -target thumb-linux -mcpu=cortex-a8 -mfpu=neon -march=thumbv7-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-THUMB-ALL %s
-// CHECK-THUMB-ALL: as{{(.exe)?}}" "-mfloat-abi=soft" "-march=thumbv7-a" "-mcpu=cortex-a8" "-mfpu=neon"
+// CHECK-THUMB-ALL: as{{(.exe)?}}" "-EL" "-mfloat-abi=soft" "-march=thumbv7-a" "-mcpu=cortex-a8" "-mfpu=neon"
 //
-// RUN: %clang -target thumb-linux -mcpu=cortex-a8 -mfpu=neon -march=thumbebv7-a -### \
+// RUN: %clang -target thumbeb-linux -mcpu=cortex-a8 -mfpu=neon -march=thumbebv7-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-THUMBEB-ALL %s
-// CHECK-THUMBEB-ALL: as{{(.exe)?}}" "-mfloat-abi=soft" "-march=thumbebv7-a" "-mcpu=cortex-a8" "-mfpu=neon"
+// CHECK-THUMBEB-ALL: as{{(.exe)?}}" "-EB" "-mfloat-abi=soft" "-march=thumbebv7-a" "-mcpu=cortex-a8" "-mfpu=neon"
 //
 // RUN: %clang -target armv7-linux -mcpu=cortex-a8 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-TARGET %s
-// CHECK-ARM-TARGET: as{{(.exe)?}}" "-mfpu=neon" "-mfloat-abi=soft" "-mcpu=cortex-a8"
+// CHECK-ARM-TARGET: as{{(.exe)?}}" "-EL" "-mfpu=neon" "-mfloat-abi=soft" "-mcpu=cortex-a8"
 //
 // RUN: %clang -target armebv7-linux -mcpu=cortex-a8 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARMEB-TARGET %s
-// CHECK-ARMEB-TARGET: as{{(.exe)?}}" "-mfpu=neon" "-mfloat-abi=soft" "-mcpu=cortex-a8"
+// CHECK-ARMEB-TARGET: as{{(.exe)?}}" "-EB" "-mfpu=neon" "-mfloat-abi=soft" "-mcpu=cortex-a8"
 //
 // RUN: %clang -target thumbv7-linux -mcpu=cortex-a8 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-THUMB-TARGET %s
-// CHECK-THUMB-TARGET: as{{(.exe)?}}" "-mfpu=neon" "-mfloat-abi=soft" "-mcpu=cortex-a8"
+// CHECK-THUMB-TARGET: as{{(.exe)?}}" "-EL" "-mfpu=neon" "-mfloat-abi=soft" "-mcpu=cortex-a8"
 //
 // RUN: %clang -target thumbebv7-linux -mcpu=cortex-a8 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-THUMBEB-TARGET %s
-// CHECK-THUMBEB-TARGET: as{{(.exe)?}}" "-mfpu=neon" "-mfloat-abi=soft" "-mcpu=cortex-a8"
+// CHECK-THUMBEB-TARGET: as{{(.exe)?}}" "-EB" "-mfpu=neon" "-mfloat-abi=soft" "-mcpu=cortex-a8"
 //
 // RUN: %clang -target armv8-linux -mcpu=cortex-a53 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-TARGET-V8 %s
-// CHECK-ARM-TARGET-V8: as{{(.exe)?}}" "-mfpu=crypto-neon-fp-armv8" "-mfloat-abi=soft" "-mcpu=cortex-a53"
+// CHECK-ARM-TARGET-V8: as{{(.exe)?}}" "-EL" "-mfpu=crypto-neon-fp-armv8" "-mfloat-abi=soft" "-mcpu=cortex-a53"
 //
 // RUN: %clang -target armebv8-linux -mcpu=cortex-a53 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARMEB-TARGET-V8 %s
-// CHECK-ARMEB-TARGET-V8: as{{(.exe)?}}" "-mfpu=crypto-neon-fp-armv8" "-mfloat-abi=soft" "-mcpu=cortex-a53"
+// CHECK-ARMEB-TARGET-V8: as{{(.exe)?}}" "-EB" "-mfpu=crypto-neon-fp-armv8" "-mfloat-abi=soft" "-mcpu=cortex-a53"
 //
 // RUN: %clang -target thumbv8-linux -mcpu=cortex-a53 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-THUMB-TARGET-V8 %s
-// CHECK-THUMB-TARGET-V8: as{{(.exe)?}}" "-mfpu=crypto-neon-fp-armv8" "-mfloat-abi=soft" "-mcpu=cortex-a53"
+// CHECK-THUMB-TARGET-V8: as{{(.exe)?}}" "-EL" "-mfpu=crypto-neon-fp-armv8" "-mfloat-abi=soft" "-mcpu=cortex-a53"
 //
 // RUN: %clang -target thumbebv8-linux -mcpu=cortex-a53 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-THUMBEB-TARGET-V8 %s
-// CHECK-THUMBEB-TARGET-V8: as{{(.exe)?}}" "-mfpu=crypto-neon-fp-armv8" "-mfloat-abi=soft" "-mcpu=cortex-a53"
+// CHECK-THUMBEB-TARGET-V8: as{{(.exe)?}}" "-EB" "-mfpu=crypto-neon-fp-armv8" "-mfloat-abi=soft" "-mcpu=cortex-a53"
 //
 // RUN: %clang -target arm-linux -mfloat-abi=hard -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-MFLOAT-ABI %s
-// CHECK-ARM-MFLOAT-ABI: as{{(.exe)?}}" "-mfloat-abi=hard"
+// CHECK-ARM-MFLOAT-ABI: as{{(.exe)?}}" "-EL" "-mfloat-abi=hard"
 //
 // RUN: %clang -target arm-linux-androideabi -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-ANDROID %s
-// CHECK-ARM-ANDROID: as{{(.exe)?}}" "-mfloat-abi=soft"
+// CHECK-ARM-ANDROID: as{{(.exe)?}}" "-EL" "-mfloat-abi=soft"
 //
 // RUN: %clang -target arm-linux-androideabi -march=armv7-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-ANDROID-SOFTFP %s
-// CHECK-ARM-ANDROID-SOFTFP: as{{(.exe)?}}" "-mfloat-abi=softfp" "-march=armv7-a"
+// CHECK-ARM-ANDROID-SOFTFP: as{{(.exe)?}}" "-EL" "-mfloat-abi=softfp" "-march=armv7-a"
 //
 // RUN: %clang -target arm-linux-eabi -mhard-float -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-HARDFP %s
-// CHECK-ARM-HARDFP: as{{(.exe)?}}" "-mfloat-abi=hard"
+// CHECK-ARM-HARDFP: as{{(.exe)?}}" "-EL" "-mfloat-abi=hard"
 //
 // RUN: %clang -target aarch64-linux-gnu -mcpu=cortex-a53 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM64-MCPU %s
-// CHECK-ARM64-MCPU: as{{(.exe)?}}" "-mcpu=cortex-a53"
+// CHECK-ARM64-MCPU: as{{(.exe)?}}" "-EL" "-mcpu=cortex-a53"
 //
 // RUN: %clang -target aarch64-linux-gnu -march=armv8-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM64-MARCH %s
-// CHECK-ARM64-MARCH: as{{(.exe)?}}" "-march=armv8-a"
+// CHECK-ARM64-MARCH: as{{(.exe)?}}" "-EL" "-march=armv8-a"
 //
 // RUN: %clang -target aarch64-linux-gnu -mcpu=cortex-a53 -march=armv8-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM64-ALL %s
-// CHECK-ARM64-ALL: as{{(.exe)?}}" "-march=armv8-a" "-mcpu=cortex-a53"
+// CHECK-ARM64-ALL: as{{(.exe)?}}" "-EL" "-march=armv8-a" "-mcpu=cortex-a53"
 //
 // RUN: %clang -target aarch64_be-linux-gnu -mcpu=cortex-a53 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
-// RUN:   | FileCheck -check-prefix=CHECK-ARM64-MCPU %s
+// RUN:   | FileCheck -check-prefix=CHECK-ARM64BE-MCPU %s
+// CHECK-ARM64BE-MCPU: as{{(.exe)?}}" "-EB" "-mcpu=cortex-a53"
 //
 // RUN: %clang -target aarch64_be-linux-gnu -march=armv8-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
-// RUN:   | FileCheck -check-prefix=CHECK-ARM64-MARCH %s
+// RUN:   | FileCheck -check-prefix=CHECK-ARM64BE-MARCH %s
+// CHECK-ARM64BE-MARCH: as{{(.exe)?}}" "-EB" "-march=armv8-a"
 //
 // RUN: %clang -target aarch64_be-linux-gnu -mcpu=cortex-a53 -march=armv8-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
-// RUN:   | FileCheck -check-prefix=CHECK-ARM64-ALL %s
+// RUN:   | FileCheck -check-prefix=CHECK-ARM64BE-ALL %s
+// CHECK-ARM64BE-ALL: as{{(.exe)?}}" "-EB" "-march=armv8-a" "-mcpu=cortex-a53"
 //
 // RUN: %clang -target ppc-linux -mcpu=invalid-cpu -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \