Index: clang/include/clang/Driver/ToolChain.h
===================================================================
--- clang/include/clang/Driver/ToolChain.h
+++ clang/include/clang/Driver/ToolChain.h
@@ -108,6 +108,12 @@
     UNW_Libgcc
   };
 
+  enum class UnwindTableLevel {
+    None,
+    Synchronous,
+    Asynchronous,
+  };
+
   enum RTTIMode {
     RM_Enabled,
     RM_Disabled,
@@ -495,9 +501,9 @@
   /// Returns true if gcov instrumentation (-fprofile-arcs or --coverage) is on.
   static bool needsGCovInstrumentation(const llvm::opt::ArgList &Args);
 
-  /// IsUnwindTablesDefault - Does this tool chain use -funwind-tables
-  /// by default.
-  virtual bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const;
+  /// How detailed should the unwind tables be by default.
+  virtual UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const;
 
   /// Test whether this toolchain supports outline atomics by default.
   virtual bool
Index: clang/lib/Driver/ToolChain.cpp
===================================================================
--- clang/lib/Driver/ToolChain.cpp
+++ clang/lib/Driver/ToolChain.cpp
@@ -287,8 +287,9 @@
   return Input.getFilename();
 }
 
-bool ToolChain::IsUnwindTablesDefault(const ArgList &Args) const {
-  return false;
+ToolChain::UnwindTableLevel
+ToolChain::getDefaultUnwindTableLevel(const ArgList &Args) const {
+  return UnwindTableLevel::None;
 }
 
 Tool *ToolChain::getClang() const {
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -5392,17 +5392,26 @@
   // -fasynchronous-unwind-tables and -fnon-call-exceptions interact in more
   // complicated ways.
   auto SanitizeArgs = TC.getSanitizerArgs(Args);
-  bool AsyncUnwindTables = Args.hasFlag(
-      options::OPT_fasynchronous_unwind_tables,
-      options::OPT_fno_asynchronous_unwind_tables,
-      (TC.IsUnwindTablesDefault(Args) || SanitizeArgs.needsUnwindTables()) &&
-          !Freestanding);
-  bool UnwindTables = Args.hasFlag(options::OPT_funwind_tables,
-                                   options::OPT_fno_unwind_tables, false);
-  if (AsyncUnwindTables)
-    CmdArgs.push_back("-funwind-tables=2");
-  else if (UnwindTables)
+  auto UnwindTables = TC.getDefaultUnwindTableLevel(Args);
+
+  if (Args.hasFlag(options::OPT_fasynchronous_unwind_tables,
+                   options::OPT_fno_asynchronous_unwind_tables,
+                   SanitizeArgs.needsUnwindTables()) &&
+      !Freestanding)
+    UnwindTables = ToolChain::UnwindTableLevel::Asynchronous;
+  else if (Args.hasFlag(options::OPT_funwind_tables,
+                        options::OPT_fno_unwind_tables, false))
+    UnwindTables = ToolChain::UnwindTableLevel::Synchronous;
+  else if (Args.hasFlag(options::OPT_fno_unwind_tables,
+                   options::OPT_fno_asynchronous_unwind_tables,
+                   options::OPT_funwind_tables, false) || Freestanding)
+    UnwindTables = ToolChain::UnwindTableLevel::None;
+
+
+  if (UnwindTables == ToolChain::UnwindTableLevel::Synchronous)
     CmdArgs.push_back("-funwind-tables=1");
+  else if (UnwindTables == ToolChain::UnwindTableLevel::Asynchronous)
+    CmdArgs.push_back("-funwind-tables=2");
 
   // Prepare `-aux-target-cpu` and `-aux-target-feature` unless
   // `--gpu-use-aux-triple-only` is specified.
@@ -7227,7 +7236,7 @@
     CmdArgs.push_back("-faddrsig");
 
   if ((Triple.isOSBinFormatELF() || Triple.isOSBinFormatMachO()) &&
-      (EH || AsyncUnwindTables || UnwindTables ||
+      (EH || UnwindTables != ToolChain::UnwindTableLevel::None ||
        DebugInfoKind != codegenoptions::NoDebugInfo))
     CmdArgs.push_back("-D__GCC_HAVE_DWARF2_CFI_ASM=1");
 
Index: clang/lib/Driver/ToolChains/CrossWindows.h
===================================================================
--- clang/lib/Driver/ToolChains/CrossWindows.h
+++ clang/lib/Driver/ToolChains/CrossWindows.h
@@ -55,7 +55,8 @@
                         const llvm::opt::ArgList &Args);
 
   bool IsIntegratedAssemblerDefault() const override { return true; }
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override;
   bool isPICDefault() const override;
   bool isPIEDefault(const llvm::opt::ArgList &Args) const override;
   bool isPICDefaultForced() const override;
Index: clang/lib/Driver/ToolChains/CrossWindows.cpp
===================================================================
--- clang/lib/Driver/ToolChains/CrossWindows.cpp
+++ clang/lib/Driver/ToolChains/CrossWindows.cpp
@@ -213,10 +213,11 @@
                                              const llvm::opt::ArgList &Args)
     : Generic_GCC(D, T, Args) {}
 
-bool CrossWindowsToolChain::IsUnwindTablesDefault(const ArgList &Args) const {
+ToolChain::UnwindTableLevel
+CrossWindowsToolChain::getDefaultUnwindTableLevel(const ArgList &Args) 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;
+  return getArch() == llvm::Triple::x86_64 ? UnwindTableLevel::Asynchronous : UnwindTableLevel::None;
 }
 
 bool CrossWindowsToolChain::isPICDefault() const {
Index: clang/lib/Driver/ToolChains/Darwin.h
===================================================================
--- clang/lib/Driver/ToolChains/Darwin.h
+++ clang/lib/Driver/ToolChains/Darwin.h
@@ -254,7 +254,8 @@
 
   bool UseObjCMixedDispatch() const override { return true; }
 
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override;
 
   RuntimeLibType GetDefaultRuntimeLibType() const override {
     return ToolChain::RLT_CompilerRT;
Index: clang/lib/Driver/ToolChains/Darwin.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Darwin.cpp
+++ clang/lib/Driver/ToolChains/Darwin.cpp
@@ -2925,13 +2925,17 @@
   return DAL;
 }
 
-bool MachO::IsUnwindTablesDefault(const ArgList &Args) const {
+ToolChain::UnwindTableLevel MachO::getDefaultUnwindTableLevel(const ArgList &Args) const {
   // Unwind tables are not emitted if -fno-exceptions is supplied (except when
   // targeting x86_64).
-  return getArch() == llvm::Triple::x86_64 ||
-         (GetExceptionModel(Args) != llvm::ExceptionHandling::SjLj &&
-          Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions,
-                       true));
+  if (getArch() == llvm::Triple::x86_64 ||
+      (GetExceptionModel(Args) != llvm::ExceptionHandling::SjLj &&
+       Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions,
+                    true)))
+    return getArch() == llvm::Triple::aarch64 ? UnwindTableLevel::Synchronous
+                                              : UnwindTableLevel::Asynchronous;
+
+  return UnwindTableLevel::None;
 }
 
 bool MachO::UseDwarfDebugFlags() const {
Index: clang/lib/Driver/ToolChains/FreeBSD.h
===================================================================
--- clang/lib/Driver/ToolChains/FreeBSD.h
+++ clang/lib/Driver/ToolChains/FreeBSD.h
@@ -73,7 +73,8 @@
 
   llvm::ExceptionHandling
   GetExceptionModel(const llvm::opt::ArgList &Args) const override;
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override;
   bool isPIEDefault(const llvm::opt::ArgList &Args) const override;
   SanitizerMask getSupportedSanitizers() const override;
   unsigned GetDefaultDwarfVersion() const override;
Index: clang/lib/Driver/ToolChains/FreeBSD.cpp
===================================================================
--- clang/lib/Driver/ToolChains/FreeBSD.cpp
+++ clang/lib/Driver/ToolChains/FreeBSD.cpp
@@ -473,7 +473,10 @@
 
 bool FreeBSD::HasNativeLLVMSupport() const { return true; }
 
-bool FreeBSD::IsUnwindTablesDefault(const ArgList &Args) const { return true; }
+ToolChain::UnwindTableLevel
+FreeBSD::getDefaultUnwindTableLevel(const ArgList &Args) const {
+  return UnwindTableLevel::Asynchronous;
+}
 
 bool FreeBSD::isPIEDefault(const llvm::opt::ArgList &Args) const {
   return getSanitizerArgs(Args).requiresPIE();
Index: clang/lib/Driver/ToolChains/Fuchsia.h
===================================================================
--- clang/lib/Driver/ToolChains/Fuchsia.h
+++ clang/lib/Driver/ToolChains/Fuchsia.h
@@ -50,8 +50,9 @@
   CXXStdlibType GetDefaultCXXStdlibType() const override {
     return ToolChain::CST_Libcxx;
   }
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override {
-    return true;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override {
+    return UnwindTableLevel::Asynchronous;
   }
   bool isPICDefault() const override { return false; }
   bool isPIEDefault(const llvm::opt::ArgList &Args) const override {
Index: clang/lib/Driver/ToolChains/Gnu.h
===================================================================
--- clang/lib/Driver/ToolChains/Gnu.h
+++ clang/lib/Driver/ToolChains/Gnu.h
@@ -296,7 +296,8 @@
 
   void printVerboseInfo(raw_ostream &OS) const override;
 
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override;
   bool isPICDefault() const override;
   bool isPIEDefault(const llvm::opt::ArgList &Args) const override;
   bool isPICDefaultForced() const override;
Index: clang/lib/Driver/ToolChains/Gnu.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Gnu.cpp
+++ clang/lib/Driver/ToolChains/Gnu.cpp
@@ -2827,7 +2827,8 @@
   RocmInstallation.print(OS);
 }
 
-bool Generic_GCC::IsUnwindTablesDefault(const ArgList &Args) const {
+ToolChain::UnwindTableLevel
+Generic_GCC::getDefaultUnwindTableLevel(const ArgList &Args) const {
   switch (getArch()) {
   case llvm::Triple::aarch64:
   case llvm::Triple::ppc:
@@ -2836,9 +2837,9 @@
   case llvm::Triple::ppc64le:
   case llvm::Triple::x86:
   case llvm::Triple::x86_64:
-    return true;
+    return UnwindTableLevel::Asynchronous;
   default:
-    return false;
+    return UnwindTableLevel::None;
   }
 }
 
Index: clang/lib/Driver/ToolChains/MSVC.h
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.h
+++ clang/lib/Driver/ToolChains/MSVC.h
@@ -51,7 +51,8 @@
                 Action::OffloadKind DeviceOffloadKind) const override;
 
   bool IsIntegratedAssemblerDefault() const override;
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override;
   bool isPICDefault() const override;
   bool isPIEDefault(const llvm::opt::ArgList &Args) const override;
   bool isPICDefaultForced() const override;
Index: clang/lib/Driver/ToolChains/MSVC.cpp
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.cpp
+++ clang/lib/Driver/ToolChains/MSVC.cpp
@@ -451,16 +451,20 @@
   return true;
 }
 
-bool MSVCToolChain::IsUnwindTablesDefault(const ArgList &Args) const {
+ToolChain::UnwindTableLevel
+MSVCToolChain::getDefaultUnwindTableLevel(const ArgList &Args) const {
   // Don't emit unwind tables by default for MachO targets.
   if (getTriple().isOSBinFormatMachO())
-    return false;
+    return UnwindTableLevel::None;
 
   // All non-x86_32 Windows targets require unwind tables. However, LLVM
   // doesn't know how to generate them for all targets, so only enable
   // the ones that are actually implemented.
-  return getArch() == llvm::Triple::x86_64 || getArch() == llvm::Triple::arm ||
-         getArch() == llvm::Triple::thumb || getArch() == llvm::Triple::aarch64;
+  if (getArch() == llvm::Triple::x86_64 || getArch() == llvm::Triple::arm ||
+      getArch() == llvm::Triple::thumb || getArch() == llvm::Triple::aarch64)
+    return UnwindTableLevel::Asynchronous;
+
+  return UnwindTableLevel::None;
 }
 
 bool MSVCToolChain::isPICDefault() const {
Index: clang/lib/Driver/ToolChains/MinGW.h
===================================================================
--- clang/lib/Driver/ToolChains/MinGW.h
+++ clang/lib/Driver/ToolChains/MinGW.h
@@ -66,7 +66,8 @@
   bool HasNativeLLVMSupport() const override;
 
   bool IsIntegratedAssemblerDefault() const override;
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override;
   bool isPICDefault() const override;
   bool isPIEDefault(const llvm::opt::ArgList &Args) const override;
   bool isPICDefaultForced() const override;
Index: clang/lib/Driver/ToolChains/MinGW.cpp
===================================================================
--- clang/lib/Driver/ToolChains/MinGW.cpp
+++ clang/lib/Driver/ToolChains/MinGW.cpp
@@ -493,15 +493,19 @@
   return NativeLLVMSupport;
 }
 
-bool toolchains::MinGW::IsUnwindTablesDefault(const ArgList &Args) const {
+ToolChain::UnwindTableLevel
+toolchains::MinGW::getDefaultUnwindTableLevel(const ArgList &Args) const {
   Arg *ExceptionArg = Args.getLastArg(options::OPT_fsjlj_exceptions,
                                       options::OPT_fseh_exceptions,
                                       options::OPT_fdwarf_exceptions);
   if (ExceptionArg &&
       ExceptionArg->getOption().matches(options::OPT_fseh_exceptions))
-    return true;
-  return getArch() == llvm::Triple::x86_64 || getArch() == llvm::Triple::arm ||
-         getArch() == llvm::Triple::thumb || getArch() == llvm::Triple::aarch64;
+    return UnwindTableLevel::Asynchronous;
+
+  if (getArch() == llvm::Triple::x86_64 || getArch() == llvm::Triple::arm ||
+      getArch() == llvm::Triple::thumb || getArch() == llvm::Triple::aarch64)
+    return UnwindTableLevel::Asynchronous;
+  return UnwindTableLevel::None;
 }
 
 bool toolchains::MinGW::isPICDefault() const {
Index: clang/lib/Driver/ToolChains/NetBSD.h
===================================================================
--- clang/lib/Driver/ToolChains/NetBSD.h
+++ clang/lib/Driver/ToolChains/NetBSD.h
@@ -65,8 +65,9 @@
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
 
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override {
-    return true;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override {
+    return UnwindTableLevel::Asynchronous;
   }
 
   llvm::ExceptionHandling GetExceptionModel(
Index: clang/lib/Driver/ToolChains/OpenBSD.h
===================================================================
--- clang/lib/Driver/ToolChains/OpenBSD.h
+++ clang/lib/Driver/ToolChains/OpenBSD.h
@@ -82,7 +82,8 @@
   std::string getCompilerRT(const llvm::opt::ArgList &Args, StringRef Component,
                             FileType Type = ToolChain::FT_Static) const override;
 
-  bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override;
 
   LangOptions::StackProtectorMode
   GetDefaultStackProtectorLevel(bool KernelOrKext) const override {
Index: clang/lib/Driver/ToolChains/OpenBSD.cpp
===================================================================
--- clang/lib/Driver/ToolChains/OpenBSD.cpp
+++ clang/lib/Driver/ToolChains/OpenBSD.cpp
@@ -363,11 +363,12 @@
 
 bool OpenBSD::HasNativeLLVMSupport() const { return true; }
 
-bool OpenBSD::IsUnwindTablesDefault(const ArgList &Args) const {
-    switch (getArch()) {
-      case llvm::Triple::arm:
-        return false;
-      default:
-        return true;
-    }
+ToolChain::UnwindTableLevel
+OpenBSD::getDefaultUnwindTableLevel(const ArgList &Args) const {
+  switch (getArch()) {
+  case llvm::Triple::arm:
+    return UnwindTableLevel::None;
+  default:
+    return UnwindTableLevel::Asynchronous;
+  }
 }
Index: clang/test/Driver/clang-translation.c
===================================================================
--- clang/test/Driver/clang-translation.c
+++ clang/test/Driver/clang-translation.c
@@ -77,7 +77,11 @@
 
 // RUN: %clang -target arm64-apple-ios10 -### -S %s -arch arm64 2>&1 | \
 // RUN: FileCheck -check-prefix=ARM64-APPLE %s
-// ARM64-APPLE: -funwind-tables=2
+// ARM64-APPLE: -funwind-tables=1
+
+// RUN: %clang -target arm64-apple-ios10 -funwind-tables -### -S %s -arch arm64 2>&1 | \
+// RUN: FileCheck -check-prefix=ARM64-APPLE-UNWIND %s
+// ARM64-APPLE-UNWIND: -funwind-tables=1
 
 // RUN: %clang -target arm64-apple-ios10 -### -ffreestanding -S %s -arch arm64 2>&1 | \
 // RUN: FileCheck -check-prefix=ARM64-FREESTANDING-APPLE %s