Index: include/clang/Driver/ToolChain.h
===================================================================
--- include/clang/Driver/ToolChain.h
+++ include/clang/Driver/ToolChain.h
@@ -353,7 +353,7 @@
 
   /// IsUnwindTablesDefault - Does this tool chain use -funwind-tables
   /// by default.
-  virtual bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const;
+  virtual bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args, bool isCXX) const;
 
   /// \brief Test whether this toolchain defaults to PIC.
   virtual bool isPICDefault() const = 0;
Index: lib/Driver/ToolChain.cpp
===================================================================
--- lib/Driver/ToolChain.cpp
+++ lib/Driver/ToolChain.cpp
@@ -220,7 +220,7 @@
   }
 }
 
-bool ToolChain::IsUnwindTablesDefault(const ArgList &Args) const {
+bool ToolChain::IsUnwindTablesDefault(const ArgList &Args, bool isCXX) const {
   return false;
 }
 
Index: lib/Driver/ToolChains/Arch/ARM.h
===================================================================
--- lib/Driver/ToolChains/Arch/ARM.h
+++ lib/Driver/ToolChains/Arch/ARM.h
@@ -52,6 +52,8 @@
 int getARMSubArchVersionNumber(const llvm::Triple &Triple);
 bool isARMMProfile(const llvm::Triple &Triple);
 
+bool ARMNeedUnwindTable(const llvm::opt::ArgList &Args, bool isCXX);
+
 } // end namespace arm
 } // end namespace tools
 } // end namespace driver
Index: lib/Driver/ToolChains/Arch/ARM.cpp
===================================================================
--- lib/Driver/ToolChains/Arch/ARM.cpp
+++ lib/Driver/ToolChains/Arch/ARM.cpp
@@ -565,3 +565,10 @@
   if (arm::getARMSubArchVersionNumber(Triple) >= 7 || arm::isARMMProfile(Triple))
     CmdArgs.push_back("--be8");
 }
+
+bool arm::ARMNeedUnwindTable(const llvm::opt::ArgList &Args, bool isCXX) {
+  // Unwind tables are emitted for C++ or if -fno-exceptions is supplied.
+  // We cannot rely on noThrow attribute because we still need the .exidx section
+  // even if the function does not throw. (Excepted for NetBSD that uses DwarfCFI).
+  return Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions, isCXX);
+}
Index: lib/Driver/ToolChains/BareMetal.h
===================================================================
--- lib/Driver/ToolChains/BareMetal.h
+++ lib/Driver/ToolChains/BareMetal.h
@@ -32,6 +32,7 @@
 
 public:
   bool useIntegratedAs() const override { return true; }
+  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args, bool isCXX) const override;
   bool isCrossCompiling() const override { return true; }
   bool isPICDefault() const override { return false; }
   bool isPIEDefault() const override { return false; }
Index: lib/Driver/ToolChains/BareMetal.cpp
===================================================================
--- lib/Driver/ToolChains/BareMetal.cpp
+++ lib/Driver/ToolChains/BareMetal.cpp
@@ -13,6 +13,7 @@
 #include "InputInfo.h"
 #include "Gnu.h"
 
+#include "Arch/ARM.h"
 #include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
@@ -57,6 +58,18 @@
   return true;
 }
 
+bool BareMetal::IsUnwindTablesDefault(const ArgList &Args, bool isCXX) const {
+  switch (getArch()) {
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    return tools::arm::ARMNeedUnwindTable(Args, isCXX);
+  default:
+    return false;
+  }
+}
+
 bool BareMetal::handlesTarget(const llvm::Triple &Triple) {
   return isARMBareMetal(Triple);
 }
Index: lib/Driver/ToolChains/Clang.cpp
===================================================================
--- lib/Driver/ToolChains/Clang.cpp
+++ lib/Driver/ToolChains/Clang.cpp
@@ -3409,13 +3409,15 @@
     CmdArgs.push_back("-mpie-copy-relocations");
   }
 
+  bool isCXX = C.getDriver().CCCIsCXX() || types::isCXX(Input.getType());
+
   // This is a coarse approximation of what llvm-gcc actually does, both
   // -fasynchronous-unwind-tables and -fnon-call-exceptions interact in more
   // complicated ways.
   bool AsynchronousUnwindTables =
       Args.hasFlag(options::OPT_fasynchronous_unwind_tables,
                    options::OPT_fno_asynchronous_unwind_tables,
-                   (getToolChain().IsUnwindTablesDefault(Args) ||
+                   (getToolChain().IsUnwindTablesDefault(Args, isCXX) ||
                     getToolChain().getSanitizerArgs().needsUnwindTables()) &&
                        !KernelOrKext);
   if (Args.hasFlag(options::OPT_funwind_tables, options::OPT_fno_unwind_tables,
Index: lib/Driver/ToolChains/CrossWindows.h
===================================================================
--- lib/Driver/ToolChains/CrossWindows.h
+++ lib/Driver/ToolChains/CrossWindows.h
@@ -56,7 +56,7 @@
                         const llvm::opt::ArgList &Args);
 
   bool IsIntegratedAssemblerDefault() const override { return true; }
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args, bool isCXX) const override;
   bool isPICDefault() const override;
   bool isPIEDefault() const override;
   bool isPICDefaultForced() const override;
Index: lib/Driver/ToolChains/CrossWindows.cpp
===================================================================
--- lib/Driver/ToolChains/CrossWindows.cpp
+++ lib/Driver/ToolChains/CrossWindows.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "CrossWindows.h"
+#include "Arch/ARM.h"
 #include "CommonArgs.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
@@ -218,10 +219,20 @@
   }
 }
 
-bool CrossWindowsToolChain::IsUnwindTablesDefault(const ArgList &Args) const {
+bool CrossWindowsToolChain::IsUnwindTablesDefault(const ArgList &Args, bool isCXX) const {
   // FIXME: all non-x86 targets need unwind tables, however, LLVM currently does
   // not know how to emit them.
-  return getArch() == llvm::Triple::x86_64;
+  switch (getArch()) {
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    return tools::arm::ARMNeedUnwindTable(Args, isCXX);
+  case llvm::Triple::x86_64:
+    return true;
+  default:
+    return false;
+  }
 }
 
 bool CrossWindowsToolChain::isPICDefault() const {
Index: lib/Driver/ToolChains/Darwin.h
===================================================================
--- lib/Driver/ToolChains/Darwin.h
+++ lib/Driver/ToolChains/Darwin.h
@@ -214,7 +214,7 @@
 
   bool UseObjCMixedDispatch() const override { return true; }
 
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args, bool isCXX) const override;
 
   RuntimeLibType GetDefaultRuntimeLibType() const override {
     return ToolChain::RLT_CompilerRT;
Index: lib/Driver/ToolChains/Darwin.cpp
===================================================================
--- lib/Driver/ToolChains/Darwin.cpp
+++ lib/Driver/ToolChains/Darwin.cpp
@@ -1837,7 +1837,7 @@
   return DAL;
 }
 
-bool MachO::IsUnwindTablesDefault(const ArgList &Args) const {
+bool MachO::IsUnwindTablesDefault(const ArgList &Args, bool isCXX) const {
   // Unwind tables are not emitted if -fno-exceptions is supplied (except when
   // targeting x86_64).
   return getArch() == llvm::Triple::x86_64 ||
Index: lib/Driver/ToolChains/Gnu.h
===================================================================
--- lib/Driver/ToolChains/Gnu.h
+++ lib/Driver/ToolChains/Gnu.h
@@ -284,7 +284,7 @@
 
   void printVerboseInfo(raw_ostream &OS) const override;
 
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args, bool isCXX) const override;
   bool isPICDefault() const override;
   bool isPIEDefault() const override;
   bool isPICDefaultForced() const override;
Index: lib/Driver/ToolChains/Gnu.cpp
===================================================================
--- lib/Driver/ToolChains/Gnu.cpp
+++ lib/Driver/ToolChains/Gnu.cpp
@@ -2175,8 +2175,22 @@
   CudaInstallation.print(OS);
 }
 
-bool Generic_GCC::IsUnwindTablesDefault(const ArgList &Args) const {
-  return getArch() == llvm::Triple::x86_64;
+bool Generic_GCC::IsUnwindTablesDefault(const ArgList &Args, bool isCXX) const {
+
+  // Unwind tables are emitted when targeting x86_64 and ARM for C++ or -fexceptions only).
+  // For ARM we cannot just use UWTable because we still need the .exidx section
+  // even if the function does not throw.
+  switch (getArch()) {
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    return tools::arm::ARMNeedUnwindTable(Args, isCXX);
+  case llvm::Triple::x86_64:
+    return true;
+  default:
+    return false;
+  }
 }
 
 bool Generic_GCC::isPICDefault() const {
Index: lib/Driver/ToolChains/MSVC.h
===================================================================
--- lib/Driver/ToolChains/MSVC.h
+++ lib/Driver/ToolChains/MSVC.h
@@ -73,7 +73,7 @@
                 Action::OffloadKind DeviceOffloadKind) const override;
 
   bool IsIntegratedAssemblerDefault() const override;
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args, bool isCXX) const override;
   bool isPICDefault() const override;
   bool isPIEDefault() const override;
   bool isPICDefaultForced() const override;
Index: lib/Driver/ToolChains/MSVC.cpp
===================================================================
--- lib/Driver/ToolChains/MSVC.cpp
+++ lib/Driver/ToolChains/MSVC.cpp
@@ -10,6 +10,7 @@
 #include "MSVC.h"
 #include "CommonArgs.h"
 #include "Darwin.h"
+#include "Arch/ARM.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/Version.h"
 #include "clang/Driver/Compilation.h"
@@ -707,7 +708,7 @@
   return true;
 }
 
-bool MSVCToolChain::IsUnwindTablesDefault(const ArgList &Args) const {
+bool MSVCToolChain::IsUnwindTablesDefault(const ArgList &Args, bool isCXX) const {
   // Emit unwind tables by default on Win64. All non-x86_32 Windows platforms
   // such as ARM and PPC actually require unwind tables, but LLVM doesn't know
   // how to generate them yet.
@@ -716,7 +717,17 @@
   if (getTriple().isOSBinFormatMachO())
     return false;
 
-  return getArch() == llvm::Triple::x86_64;
+  switch (getArch()) {
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    return tools::arm::ARMNeedUnwindTable(Args, isCXX);
+  case llvm::Triple::x86_64:
+    return true;
+  default:
+    return false;
+  }
 }
 
 bool MSVCToolChain::isPICDefault() const {
Index: lib/Driver/ToolChains/MinGW.h
===================================================================
--- lib/Driver/ToolChains/MinGW.h
+++ lib/Driver/ToolChains/MinGW.h
@@ -60,7 +60,7 @@
         const llvm::opt::ArgList &Args);
 
   bool IsIntegratedAssemblerDefault() const override;
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args, bool isCXX) const override;
   bool isPICDefault() const override;
   bool isPIEDefault() const override;
   bool isPICDefaultForced() const override;
Index: lib/Driver/ToolChains/MinGW.cpp
===================================================================
--- lib/Driver/ToolChains/MinGW.cpp
+++ lib/Driver/ToolChains/MinGW.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "MinGW.h"
+#include "Arch/ARM.h"
 #include "InputInfo.h"
 #include "CommonArgs.h"
 #include "clang/Driver/Compilation.h"
@@ -358,8 +359,19 @@
   return new tools::MinGW::Linker(*this);
 }
 
-bool toolchains::MinGW::IsUnwindTablesDefault(const ArgList &Args) const {
-  return getArch() == llvm::Triple::x86_64;
+bool toolchains::MinGW::IsUnwindTablesDefault(const ArgList &Args, bool isCXX) const {
+  // Unwind tables are emitted when targeting x86_64 and ARM for C++ or -fexceptions).
+  switch (getArch()) {
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    return tools::arm::ARMNeedUnwindTable(Args, isCXX);
+  case llvm::Triple::x86_64:
+    return true;
+  default:
+    return false;
+  }
 }
 
 bool toolchains::MinGW::isPICDefault() const {
Index: lib/Driver/ToolChains/NetBSD.h
===================================================================
--- lib/Driver/ToolChains/NetBSD.h
+++ lib/Driver/ToolChains/NetBSD.h
@@ -65,7 +65,7 @@
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
 
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override {
+  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args, bool isCXX) const override {
     return true;
   }
 
Index: test/Driver/arm-unwind.c
===================================================================
--- /dev/null
+++ test/Driver/arm-unwind.c
@@ -0,0 +1,9 @@
+// Do not add function attribute "uwtable" for arm ehabi targets for C mode.
+
+// RUN: %clang -target arm-none-eabi  -### -S %s -o %t.s 2>&1 \
+// RUN: | FileCheck --check-prefix=CHECK-EABI %s
+// CHECK-EABI-NOT: -munwind-tables
+
+// RUN: %clang -target arm--linux-gnueabihf -### -S %s -o %t.s 2>&1 \
+// RUN: | FileCheck --check-prefix=CHECK-GNU %s
+// CHECK-GNU-NOT: -munwind-tables
Index: test/Driver/arm-unwind.cpp
===================================================================
--- /dev/null
+++ test/Driver/arm-unwind.cpp
@@ -0,0 +1,9 @@
+// Add function attribute "uwtable" for arm ehabi targets in C++.
+
+// RUN: %clang -target arm-none-eabi  -### -S %s -o %t.s 2>&1 \
+// RUN:    | FileCheck --check-prefix=CHECK-EABI %s
+// CHECK-EABI: -munwind-tables
+
+// RUN: %clang -target arm-none-eabi  -### -S %s -o %t.s 2>&1 \
+// RUN:    | FileCheck --check-prefix=CHECK-GNU %s
+// CHECK-GNU: -munwind-tables