Index: lldb/include/lldb/Utility/ArchSpec.h
===================================================================
--- lldb/include/lldb/Utility/ArchSpec.h
+++ lldb/include/lldb/Utility/ArchSpec.h
@@ -122,6 +122,7 @@
     eCore_thumbv7em,
     eCore_arm_arm64,
     eCore_arm_armv8,
+    eCore_arm_arm64_32,
     eCore_arm_aarch64,
 
     eCore_mips32,
Index: lldb/packages/Python/lldbsuite/test/arm/breakpoint-it/TestBreakpointIt.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/arm/breakpoint-it/TestBreakpointIt.py
+++ lldb/packages/Python/lldbsuite/test/arm/breakpoint-it/TestBreakpointIt.py
@@ -17,7 +17,7 @@
     NO_DEBUG_INFO_TESTCASE = True
 
     @skipIf(archs=no_match(["arm"]))
-    @skipIf(archs=["arm64", "arm64e"])
+    @skipIf(archs=["arm64", "arm64e", "arm64_32"])
     def test_false(self):
         self.build()
         exe = self.getBuildArtifact("a.out")
@@ -31,7 +31,7 @@
                 "Breakpoint does not get hit")
 
     @skipIf(archs=no_match(["arm"]))
-    @skipIf(archs=["arm64", "arm64e"])
+    @skipIf(archs=["arm64", "arm64e", "arm64_32"])
     def test_true(self):
         self.build()
         exe = self.getBuildArtifact("a.out")
Index: lldb/packages/Python/lldbsuite/test/commands/expression/call-function/TestCallStdStringFunction.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/commands/expression/call-function/TestCallStdStringFunction.py
+++ lldb/packages/Python/lldbsuite/test/commands/expression/call-function/TestCallStdStringFunction.py
@@ -50,7 +50,7 @@
         # skip this part of the test.
         triple = self.dbg.GetSelectedPlatform().GetTriple()
         do_cstr_test = True
-        if triple == "arm64-apple-ios" or triple == "arm64-apple-tvos" or triple == "armv7k-apple-watchos" or triple == "arm64-apple-bridgeos":
+        if triple in ["arm64-apple-ios", "arm64e-apple-ios", "arm64-apple-tvos", "armv7k-apple-watchos", "arm64-apple-bridgeos", "arm64_32-apple-watchos"]:
             do_cstr_test = False
         if do_cstr_test:
             self.expect("print str.c_str()",
Index: lldb/packages/Python/lldbsuite/test/commands/expression/char/TestExprsChar.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/commands/expression/char/TestExprsChar.py
+++ lldb/packages/Python/lldbsuite/test/commands/expression/char/TestExprsChar.py
@@ -59,8 +59,10 @@
             "i[3-6]86",
             "x86_64",
             "arm64",
+            'arm64e',
             'armv7',
-            'armv7k'],
+            'armv7k',
+            'arm64_32'],
         bugnumber="llvm.org/pr23069, <rdar://problem/28721938>")
     @expectedFailureAll(triple='mips*', bugnumber="llvm.org/pr23069")
     def test_unsigned_char(self):
Index: lldb/packages/Python/lldbsuite/test/commands/expression/persist_objc_pointeetype/TestPersistObjCPointeeType.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/commands/expression/persist_objc_pointeetype/TestPersistObjCPointeeType.py
+++ lldb/packages/Python/lldbsuite/test/commands/expression/persist_objc_pointeetype/TestPersistObjCPointeeType.py
@@ -23,7 +23,7 @@
 
     @skipUnlessDarwin
     @skipIf(archs=["i386", "i686"])
-    @skipIf(debug_info="gmodules", archs=['arm64', 'armv7', 'armv7k'])  # compile error with gmodules for iOS
+    @skipIf(debug_info="gmodules", archs=['arm64', 'armv7', 'armv7k', 'arm64e', 'arm64_32'])  # compile error with gmodules for iOS
     def test_with(self):
         """Test that we can p *objcObject"""
         self.build()
Index: lldb/packages/Python/lldbsuite/test/commands/register/register/register_command/TestRegisters.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/commands/register/register/register_command/TestRegisters.py
+++ lldb/packages/Python/lldbsuite/test/commands/register/register/register_command/TestRegisters.py
@@ -44,7 +44,7 @@
             self.runCmd("register read xmm0")
             self.runCmd("register read ymm15")  # may be available
             self.runCmd("register read bnd0")  # may be available
-        elif self.getArchitecture() in ['arm', 'armv7', 'armv7k', 'arm64']:
+        elif self.getArchitecture() in ['arm', 'armv7', 'armv7k', 'arm64', 'arm64e', 'arm64_32']:
             self.runCmd("register read s0")
             self.runCmd("register read q15")  # may be available
 
@@ -89,7 +89,7 @@
         if self.getArchitecture() in ['amd64', 'i386', 'x86_64']:
             gpr = "eax"
             vector = "xmm0"
-        elif self.getArchitecture() in ['arm64', 'aarch64']:
+        elif self.getArchitecture() in ['arm64', 'aarch64', 'arm64e', 'arm64_32']:
             gpr = "w0"
             vector = "v0"
         elif self.getArchitecture() in ['arm', 'armv7', 'armv7k']:
@@ -335,7 +335,7 @@
                     ("xmm15",
                      "{0x01 0x02 0x03 0x00 0x00 0x00 0x00 0x00 0x09 0x0a 0x2f 0x2f 0x2f 0x2f 0x0e 0x0f}",
                      False))
-        elif self.getArchitecture() in ['arm64', 'aarch64']:
+        elif self.getArchitecture() in ['arm64', 'aarch64', 'arm64e', 'arm64_32']:
             reg_list = [
                 # reg      value
                 # must-have
Index: lldb/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-objc/nsindexpath/TestDataFormatterNSIndexPath.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-objc/nsindexpath/TestDataFormatterNSIndexPath.py
+++ lldb/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-objc/nsindexpath/TestDataFormatterNSIndexPath.py
@@ -43,7 +43,7 @@
 
     @skipUnlessDarwin
     @expectedFailureAll(archs=['i386'], bugnumber="rdar://28656605")
-    @expectedFailureAll(archs=['armv7', 'armv7k'], bugnumber="rdar://problem/34561607") # NSIndexPath formatter isn't working for 32-bit arm
+    @expectedFailureAll(archs=['armv7', 'armv7k', 'arm64_32'], bugnumber="rdar://problem/34561607") # NSIndexPath formatter isn't working for 32-bit arm
     def test_nsindexpath_with_run_command(self):
         """Test formatters for NSIndexPath."""
         self.appkit_tester_impl(self.nsindexpath_data_formatter_commands)
Index: lldb/packages/Python/lldbsuite/test/lldbplatformutil.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/lldbplatformutil.py
+++ lldb/packages/Python/lldbsuite/test/lldbplatformutil.py
@@ -27,7 +27,7 @@
         test_case.expect("register read eax", substrs=['eax = 0x'])
     elif arch in ['arm', 'armv7', 'armv7k']:
         test_case.expect("register read r0", substrs=['r0 = 0x'])
-    elif arch in ['aarch64', 'arm64']:
+    elif arch in ['aarch64', 'arm64', 'arm64e', 'arm64_32']:
         test_case.expect("register read x0", substrs=['x0 = 0x'])
     elif re.match("mips", arch):
         test_case.expect("register read zero", substrs=['zero = 0x'])
Index: lldb/packages/Python/lldbsuite/test/python_api/watchpoint/TestWatchpointIter.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/python_api/watchpoint/TestWatchpointIter.py
+++ lldb/packages/Python/lldbsuite/test/python_api/watchpoint/TestWatchpointIter.py
@@ -18,7 +18,7 @@
 
     # hardware watchpoints are not reported with a hardware index # on armv7 on ios devices
     def affected_by_radar_34564183(self):
-        return (self.getArchitecture() == 'armv7' or self.getArchitecture() == 'armv7k') and self.platformIsDarwin()
+        return (self.getArchitecture() in ['armv7', 'armv7k', 'arm64_32']) and self.platformIsDarwin()
 
     def setUp(self):
         # Call super's setUp().
Index: lldb/source/Host/common/NativeProcessProtocol.cpp
===================================================================
--- lldb/source/Host/common/NativeProcessProtocol.cpp
+++ lldb/source/Host/common/NativeProcessProtocol.cpp
@@ -527,6 +527,7 @@
 
   switch (GetArchitecture().GetMachine()) {
   case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_32:
     return llvm::makeArrayRef(g_aarch64_opcode);
 
   case llvm::Triple::x86:
@@ -563,6 +564,7 @@
 
   case llvm::Triple::arm:
   case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_32:
   case llvm::Triple::mips64:
   case llvm::Triple::mips64el:
   case llvm::Triple::mips:
Index: lldb/source/Host/macosx/objcxx/Host.mm
===================================================================
--- lldb/source/Host/macosx/objcxx/Host.mm
+++ lldb/source/Host/macosx/objcxx/Host.mm
@@ -471,6 +471,12 @@
         break;
 #endif
 
+#if defined(CPU_TYPE_ARM64_32) && defined(CPU_SUBTYPE_ARM64_32_ALL)
+      case CPU_TYPE_ARM64_32:
+        sub = CPU_SUBTYPE_ARM64_32_ALL;
+        break;
+#endif
+
       case CPU_TYPE_ARM: {
         // Note that we fetched the cpu type from the PROCESS but we can't get a
         // cpusubtype of the
Index: lldb/source/Host/macosx/objcxx/HostInfoMacOSX.mm
===================================================================
--- lldb/source/Host/macosx/objcxx/HostInfoMacOSX.mm
+++ lldb/source/Host/macosx/objcxx/HostInfoMacOSX.mm
@@ -42,6 +42,11 @@
 #define CPU_TYPE_ARM64 (CPU_TYPE_ARM | CPU_ARCH_ABI64)
 #endif
 
+#ifndef CPU_TYPE_ARM64_32
+#define CPU_ARCH_ABI64_32 0x02000000
+#define (CPU_TYPE_ARM | CPU_ARCH_ABI64_32)
+#endif
+
 #include <TargetConditionals.h> // for TARGET_OS_TV, TARGET_OS_WATCH
 
 using namespace lldb_private;
@@ -257,7 +262,9 @@
       arch_32.SetArchitecture(eArchTypeMachO, cputype & ~(CPU_ARCH_MASK),
                               cpusubtype32);
 
-      if (cputype == CPU_TYPE_ARM || cputype == CPU_TYPE_ARM64) {
+      if (cputype == CPU_TYPE_ARM || 
+          cputype == CPU_TYPE_ARM64 || 
+          cputype == CPU_TYPE_ARM64_32) {
 // When running on a watch or tv, report the host os correctly
 #if defined(TARGET_OS_TV) && TARGET_OS_TV == 1
         arch_32.GetTriple().setOS(llvm::Triple::TvOS);
@@ -265,6 +272,9 @@
 #elif defined(TARGET_OS_BRIDGE) && TARGET_OS_BRIDGE == 1
         arch_32.GetTriple().setOS(llvm::Triple::BridgeOS);
         arch_64.GetTriple().setOS(llvm::Triple::BridgeOS);
+#elif defined(TARGET_OS_WATCHOS) && TARGET_OS_WATCHOS == 1
+        arch_32.GetTriple().setOS(llvm::Triple::WatchOS);
+        arch_64.GetTriple().setOS(llvm::Triple::WatchOS);
 #else
         arch_32.GetTriple().setOS(llvm::Triple::IOS);
         arch_64.GetTriple().setOS(llvm::Triple::IOS);
Index: lldb/source/Plugins/ABI/MacOSX-arm64/ABIMacOSX_arm64.cpp
===================================================================
--- lldb/source/Plugins/ABI/MacOSX-arm64/ABIMacOSX_arm64.cpp
+++ lldb/source/Plugins/ABI/MacOSX-arm64/ABIMacOSX_arm64.cpp
@@ -1665,7 +1665,8 @@
   const llvm::Triple::VendorType vendor_type = arch.GetTriple().getVendor();
 
   if (vendor_type == llvm::Triple::Apple) {
-    if (arch_type == llvm::Triple::aarch64) {
+    if (arch_type == llvm::Triple::aarch64 || 
+        arch_type == llvm::Triple::aarch64_32) {
       return ABISP(
           new ABIMacOSX_arm64(std::move(process_sp), MakeMCRegisterInfo(arch)));
     }
Index: lldb/source/Plugins/ABI/SysV-arm64/ABISysV_arm64.cpp
===================================================================
--- lldb/source/Plugins/ABI/SysV-arm64/ABISysV_arm64.cpp
+++ lldb/source/Plugins/ABI/SysV-arm64/ABISysV_arm64.cpp
@@ -1668,7 +1668,8 @@
   const llvm::Triple::VendorType vendor_type = arch.GetTriple().getVendor();
 
   if (vendor_type != llvm::Triple::Apple) {
-    if (arch_type == llvm::Triple::aarch64) {
+    if (arch_type == llvm::Triple::aarch64 ||
+        arch_type == llvm::Triple::aarch64_32) {
       return ABISP(
           new ABISysV_arm64(std::move(process_sp), MakeMCRegisterInfo(arch)));
     }
Index: lldb/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp
===================================================================
--- lldb/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp
+++ lldb/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp
@@ -1189,10 +1189,12 @@
 
   // If any AArch64 variant, enable the ARMv8.5 ISA with SVE extensions so we
   // can disassemble newer instructions.
-  if (triple.getArch() == llvm::Triple::aarch64)
+  if (triple.getArch() == llvm::Triple::aarch64 || 
+      triple.getArch() == llvm::Triple::aarch64_32)
     features_str += "+v8.5a,+sve2";
 
-  if (triple.getArch() == llvm::Triple::aarch64
+  if ((triple.getArch() == llvm::Triple::aarch64 ||
+       triple.getArch() == llvm::Triple::aarch64_32)
       && triple.getVendor() == llvm::Triple::Apple) {
     cpu = "apple-latest";
   }
Index: lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
+++ lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
@@ -234,7 +234,8 @@
       ReadDYLDInfoFromMemoryAndSetNotificationCallback(0x7fff5fc00000ull);
     } else if (exe_arch.GetMachine() == llvm::Triple::arm ||
                exe_arch.GetMachine() == llvm::Triple::thumb ||
-               exe_arch.GetMachine() == llvm::Triple::aarch64) {
+               exe_arch.GetMachine() == llvm::Triple::aarch64 ||
+               exe_arch.GetMachine() == llvm::Triple::aarch64_32) {
       ReadDYLDInfoFromMemoryAndSetNotificationCallback(0x2fe00000);
     } else {
       ReadDYLDInfoFromMemoryAndSetNotificationCallback(0x8fe00000);
Index: lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
===================================================================
--- lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
+++ lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
@@ -302,7 +302,8 @@
 
   Target *target = exe_ctx.GetTargetPtr();
   if (target) {
-    if (target->GetArchitecture().GetMachine() == llvm::Triple::aarch64) {
+    if (target->GetArchitecture().GetMachine() == llvm::Triple::aarch64 ||
+        target->GetArchitecture().GetMachine() == llvm::Triple::aarch64_32) {
       target_specific_defines = "typedef bool BOOL;\n";
     }
     if (target->GetArchitecture().GetMachine() == llvm::Triple::x86_64) {
Index: lldb/source/Plugins/Instruction/ARM64/EmulateInstructionARM64.cpp
===================================================================
--- lldb/source/Plugins/Instruction/ARM64/EmulateInstructionARM64.cpp
+++ lldb/source/Plugins/Instruction/ARM64/EmulateInstructionARM64.cpp
@@ -149,7 +149,8 @@
                                         InstructionType inst_type) {
   if (EmulateInstructionARM64::SupportsEmulatingInstructionsOfTypeStatic(
           inst_type)) {
-    if (arch.GetTriple().getArch() == llvm::Triple::aarch64) {
+    if (arch.GetTriple().getArch() == llvm::Triple::aarch64 ||
+        arch.GetTriple().getArch() == llvm::Triple::aarch64_32) {
       return new EmulateInstructionARM64(arch);
     }
   }
Index: lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
===================================================================
--- lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
+++ lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
@@ -5189,6 +5189,7 @@
             }
             break;
           case llvm::MachO::CPU_TYPE_ARM64:
+          case llvm::MachO::CPU_TYPE_ARM64_32:
             if (flavor == 6) // ARM_THREAD_STATE64 from mach/arm/thread_status.h
             {
               offset += 256; // This is the offset of pc in the GPR thread state
@@ -5469,6 +5470,7 @@
 
       switch (m_header.cputype) {
       case llvm::MachO::CPU_TYPE_ARM64:
+      case llvm::MachO::CPU_TYPE_ARM64_32:
         reg_ctx_sp =
             std::make_shared<RegisterContextDarwin_arm64_Mach>(thread, data);
         break;
@@ -6029,6 +6031,7 @@
     bool make_core = false;
     switch (target_arch.GetMachine()) {
     case llvm::Triple::aarch64:
+    case llvm::Triple::aarch64_32:
     case llvm::Triple::arm:
     case llvm::Triple::thumb:
     case llvm::Triple::x86:
@@ -6131,6 +6134,7 @@
           if (thread_sp) {
             switch (mach_header.cputype) {
             case llvm::MachO::CPU_TYPE_ARM64:
+            case llvm::MachO::CPU_TYPE_ARM64_32:
               RegisterContextDarwin_arm64_Mach::Create_LC_THREAD(
                   thread_sp.get(), LC_THREAD_datas[thread_idx]);
               break;
Index: lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
===================================================================
--- lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
+++ lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
@@ -418,11 +418,10 @@
 
   llvm::Triple::ArchType machine = target.GetArchitecture().GetMachine();
   switch (machine) {
+  case llvm::Triple::aarch64_32:
   case llvm::Triple::aarch64: {
-    // TODO: fix this with actual darwin breakpoint opcode for arm64.
-    // right now debugging uses the Z packets with GDB remote so this is not
-    // needed, but the size needs to be correct...
-    static const uint8_t g_arm64_breakpoint_opcode[] = {0xFE, 0xDE, 0xFF, 0xE7};
+    // 'brk #0' or 0xd4200000 in BE byte order
+    static const uint8_t g_arm64_breakpoint_opcode[] = {0x00, 0x00, 0x20, 0xD4};
     trap_opcode = g_arm64_breakpoint_opcode;
     trap_opcode_size = sizeof(g_arm64_breakpoint_opcode);
   } break;
Index: lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleWatch.cpp
===================================================================
--- lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleWatch.cpp
+++ lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleWatch.cpp
@@ -75,6 +75,7 @@
     switch (arch->GetMachine()) {
     case llvm::Triple::arm:
     case llvm::Triple::aarch64:
+    case llvm::Triple::aarch64_32:
     case llvm::Triple::thumb: {
       const llvm::Triple &triple = arch->GetTriple();
       llvm::Triple::VendorType vendor = triple.getVendor();
@@ -176,6 +177,9 @@
     case 6:
       arch.SetTriple("thumbv7s-apple-watchos");
       return true;
+    case 7:
+      arch.SetTriple("arm64_32-apple-watchos");
+      return true;
     default:
       break;
     }
@@ -204,6 +208,9 @@
     case 6:
       arch.SetTriple("thumbv7s-apple-watchos");
       return true;
+    case 7:
+      arch.SetTriple("arm64_32-apple-watchos");
+      return true;
     default:
       break;
     }
@@ -229,6 +236,9 @@
     case 5:
       arch.SetTriple("thumbv7s-apple-watchos");
       return true;
+    case 6:
+      arch.SetTriple("arm64_32-apple-watchos");
+      return true;
     default:
       break;
     }
@@ -254,6 +264,9 @@
     case 5:
       arch.SetTriple("thumbv7s-apple-watchos");
       return true;
+    case 6:
+      arch.SetTriple("arm64_32-apple-watchos");
+      return true;
     default:
       break;
     }
@@ -273,6 +286,9 @@
     case 3:
       arch.SetTriple("thumbv7-apple-watchos");
       return true;
+    case 4:
+      arch.SetTriple("arm64_32-apple-watchos");
+      return true;
     default:
       break;
     }
Index: lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
===================================================================
--- lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
+++ lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
@@ -536,6 +536,7 @@
   if (!generic_regs_specified) {
     switch (arch.GetMachine()) {
     case llvm::Triple::aarch64:
+    case llvm::Triple::aarch64_32:
     case llvm::Triple::aarch64_be:
       for (auto &reg : m_regs) {
         if (strcmp(reg.name, "pc") == 0)
Index: lldb/source/Plugins/Process/Utility/RegisterContextPOSIX_arm64.cpp
===================================================================
--- lldb/source/Plugins/Process/Utility/RegisterContextPOSIX_arm64.cpp
+++ lldb/source/Plugins/Process/Utility/RegisterContextPOSIX_arm64.cpp
@@ -109,6 +109,7 @@
 
   switch (register_info->m_target_arch.GetMachine()) {
   case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_32:
     m_reg_info.num_registers = k_num_registers_arm64;
     m_reg_info.num_gpr_registers = k_num_gpr_registers_arm64;
     m_reg_info.num_fpr_registers = k_num_fpr_registers_arm64;
@@ -184,6 +185,7 @@
   if (IsRegisterSetAvailable(set)) {
     switch (m_register_info_up->m_target_arch.GetMachine()) {
     case llvm::Triple::aarch64:
+    case llvm::Triple::aarch64_32:
       return &g_reg_sets_arm64[set];
     default:
       assert(false && "Unhandled target architecture.");
Index: lldb/source/Plugins/Process/Utility/RegisterInfoPOSIX_arm64.cpp
===================================================================
--- lldb/source/Plugins/Process/Utility/RegisterInfoPOSIX_arm64.cpp
+++ lldb/source/Plugins/Process/Utility/RegisterInfoPOSIX_arm64.cpp
@@ -57,6 +57,7 @@
 GetRegisterInfoPtr(const lldb_private::ArchSpec &target_arch) {
   switch (target_arch.GetMachine()) {
   case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_32:
     return g_register_infos_arm64_le;
   default:
     assert(false && "Unhandled target architecture.");
@@ -68,6 +69,7 @@
 GetRegisterInfoCount(const lldb_private::ArchSpec &target_arch) {
   switch (target_arch.GetMachine()) {
   case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_32:
     return static_cast<uint32_t>(sizeof(g_register_infos_arm64_le) /
                                  sizeof(g_register_infos_arm64_le[0]));
   default:
Index: lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
===================================================================
--- lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
+++ lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
@@ -416,6 +416,7 @@
       }
       break;
 
+    case llvm::Triple::aarch64_32:
     case llvm::Triple::aarch64: {
       if (exc_code == 1 && exc_sub_code == 0) // EXC_ARM_BREAKPOINT
       {
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1271,6 +1271,7 @@
                 host_triple.getOS() == llvm::Triple::Darwin) {
               switch (m_host_arch.GetMachine()) {
               case llvm::Triple::aarch64:
+              case llvm::Triple::aarch64_32:
               case llvm::Triple::arm:
               case llvm::Triple::thumb:
                 host_triple.setOS(llvm::Triple::IOS);
@@ -3162,7 +3163,8 @@
       if (arch.IsValid() &&
           arch.GetTriple().getVendor() == llvm::Triple::Apple &&
           arch.GetTriple().getOS() == llvm::Triple::IOS &&
-          arch.GetTriple().getArch() == llvm::Triple::aarch64) {
+          (arch.GetTriple().getArch() == llvm::Triple::aarch64 ||
+           arch.GetTriple().getArch() == llvm::Triple::aarch64_32)) {
         m_avoid_g_packets = eLazyBoolYes;
         uint32_t gdb_server_version = GetGDBServerProgramVersion();
         if (gdb_server_version != 0) {
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -231,6 +231,7 @@
 
 #else
   if (host_arch.GetMachine() == llvm::Triple::aarch64 ||
+      host_arch.GetMachine() == llvm::Triple::aarch64_32 ||
       host_arch.GetMachine() == llvm::Triple::aarch64_be ||
       host_arch.GetMachine() == llvm::Triple::arm ||
       host_arch.GetMachine() == llvm::Triple::armeb || host_arch.IsMIPS())
@@ -1234,6 +1235,7 @@
       case llvm::Triple::arm:
       case llvm::Triple::thumb:
       case llvm::Triple::aarch64:
+      case llvm::Triple::aarch64_32:
         ostype = "ios";
         break;
       default:
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
@@ -637,7 +637,9 @@
       if (m_thread.GetProcess().get()) {
         const ArchSpec &arch =
             m_thread.GetProcess()->GetTarget().GetArchitecture();
-        if (arch.IsValid() && arch.GetMachine() == llvm::Triple::aarch64 &&
+        if (arch.IsValid() && 
+            (arch.GetMachine() == llvm::Triple::aarch64 ||
+             arch.GetMachine() == llvm::Triple::aarch64_32) &&
             arch.GetTriple().getVendor() == llvm::Triple::Apple &&
             arch.GetTriple().getOS() == llvm::Triple::IOS) {
           arm64_debugserver = true;
Index: lldb/source/Symbol/ClangASTContext.cpp
===================================================================
--- lldb/source/Symbol/ClangASTContext.cpp
+++ lldb/source/Symbol/ClangASTContext.cpp
@@ -578,6 +578,7 @@
           fixed_arch.GetTriple().getOS() == llvm::Triple::UnknownOS) {
         if (fixed_arch.GetTriple().getArch() == llvm::Triple::arm ||
             fixed_arch.GetTriple().getArch() == llvm::Triple::aarch64 ||
+            fixed_arch.GetTriple().getArch() == llvm::Triple::aarch64_32 ||
             fixed_arch.GetTriple().getArch() == llvm::Triple::thumb) {
           fixed_arch.GetTriple().setOS(llvm::Triple::IOS);
         } else {
Index: lldb/source/Symbol/CompactUnwindInfo.cpp
===================================================================
--- lldb/source/Symbol/CompactUnwindInfo.cpp
+++ lldb/source/Symbol/CompactUnwindInfo.cpp
@@ -213,7 +213,8 @@
         return CreateUnwindPlan_x86_64(target, function_info, unwind_plan,
                                        addr);
       }
-      if (arch.GetTriple().getArch() == llvm::Triple::aarch64) {
+      if (arch.GetTriple().getArch() == llvm::Triple::aarch64 ||
+          arch.GetTriple().getArch() == llvm::Triple::aarch64_32) {
         return CreateUnwindPlan_arm64(target, function_info, unwind_plan, addr);
       }
       if (arch.GetTriple().getArch() == llvm::Triple::x86) {
Index: lldb/source/Target/Platform.cpp
===================================================================
--- lldb/source/Target/Platform.cpp
+++ lldb/source/Target/Platform.cpp
@@ -1816,6 +1816,7 @@
   size_t trap_opcode_size = 0;
 
   switch (arch.GetMachine()) {
+  case llvm::Triple::aarch64_32:
   case llvm::Triple::aarch64: {
     static const uint8_t g_aarch64_opcode[] = {0x00, 0x00, 0x20, 0xd4};
     trap_opcode = g_aarch64_opcode;
Index: lldb/source/Target/Thread.cpp
===================================================================
--- lldb/source/Target/Thread.cpp
+++ lldb/source/Target/Thread.cpp
@@ -2050,6 +2050,7 @@
     case llvm::Triple::x86:
     case llvm::Triple::arm:
     case llvm::Triple::aarch64:
+    case llvm::Triple::aarch64_32:
     case llvm::Triple::thumb:
     case llvm::Triple::mips:
     case llvm::Triple::mipsel:
Index: lldb/source/Utility/ArchSpec.cpp
===================================================================
--- lldb/source/Utility/ArchSpec.cpp
+++ lldb/source/Utility/ArchSpec.cpp
@@ -101,6 +101,8 @@
      ArchSpec::eCore_arm_arm64, "arm64"},
     {eByteOrderLittle, 8, 4, 4, llvm::Triple::aarch64,
      ArchSpec::eCore_arm_armv8, "armv8"},
+    {eByteOrderLittle, 4, 4, 4, llvm::Triple::aarch64_32,
+      ArchSpec::eCore_arm_arm64_32, "arm64_32"},
     {eByteOrderLittle, 8, 4, 4, llvm::Triple::aarch64,
      ArchSpec::eCore_arm_aarch64, "aarch64"},
 
@@ -296,6 +298,10 @@
      SUBTYPE_MASK},
     {ArchSpec::eCore_arm_arm64, llvm::MachO::CPU_TYPE_ARM64, 13, UINT32_MAX,
      SUBTYPE_MASK},
+    {ArchSpec::eCore_arm_arm64_32, llvm::MachO::CPU_TYPE_ARM64_32, 0,
+     UINT32_MAX, SUBTYPE_MASK},
+    {ArchSpec::eCore_arm_arm64_32, llvm::MachO::CPU_TYPE_ARM64_32, 1,
+     UINT32_MAX, SUBTYPE_MASK},
     {ArchSpec::eCore_arm_arm64, llvm::MachO::CPU_TYPE_ARM64, CPU_ANY,
      UINT32_MAX, SUBTYPE_MASK},
     {ArchSpec::eCore_thumb, llvm::MachO::CPU_TYPE_ARM, 0, UINT32_MAX,
@@ -752,6 +758,7 @@
     return true;
 
   case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_32:
   case llvm::Triple::aarch64_be:
   case llvm::Triple::arm:
   case llvm::Triple::armeb:
@@ -1215,6 +1222,8 @@
         return true;
       if (core2 == ArchSpec::eCore_arm_aarch64)
         return true;
+      if (core2 == ArchSpec::eCore_arm_arm64_32)
+        return true;
       try_inverse = false;
     }
     break;
@@ -1225,6 +1234,8 @@
         return true;
       if (core2 == ArchSpec::eCore_arm_armv8)
         return true;
+      if (core2 == ArchSpec::eCore_arm_arm64_32)
+        return true;
       try_inverse = false;
     }
     break;
@@ -1235,6 +1246,20 @@
         return true;
       if (core2 == ArchSpec::eCore_arm_armv8)
         return true;
+      if (core2 == ArchSpec::eCore_arm_arm64_32)
+        return true;
+      try_inverse = false;
+    }
+    break;
+
+  case ArchSpec::eCore_arm_arm64_32:
+    if (!enforce_exact_match) {
+      if (core2 == ArchSpec::eCore_arm_arm64)
+        return true;
+      if (core2 == ArchSpec::eCore_arm_armv8)
+        return true;
+      if (core2 == ArchSpec::eCore_arm_aarch64)
+        return true;
       try_inverse = false;
     }
     break;
Index: lldb/tools/compact-unwind/compact-unwind-dumper.c
===================================================================
--- lldb/tools/compact-unwind/compact-unwind-dumper.c
+++ lldb/tools/compact-unwind/compact-unwind-dumper.c
@@ -1149,7 +1149,7 @@
     print_encoding_x86_64(baton, function_start, encoding);
   } else if (baton.cputype == CPU_TYPE_I386) {
     print_encoding_i386(baton, function_start, encoding);
-  } else if (baton.cputype == CPU_TYPE_ARM64) {
+  } else if (baton.cputype == CPU_TYPE_ARM64 || baton.cputype == CPU_TYPE_ARM64_32) {
     print_encoding_arm64(baton, function_start, encoding);
   } else if (baton.cputype == CPU_TYPE_ARM) {
     print_encoding_armv7(baton, function_start, encoding);
Index: lldb/tools/debugserver/source/DNB.cpp
===================================================================
--- lldb/tools/debugserver/source/DNB.cpp
+++ lldb/tools/debugserver/source/DNB.cpp
@@ -1719,7 +1719,8 @@
     else if ((strcasecmp(arch, "x86_64") == 0) ||
              (strcasecmp(arch, "x86_64h") == 0))
       return DNBArchProtocol::SetArchitecture(CPU_TYPE_X86_64);
-    else if (strstr(arch, "arm64_32") == arch)
+    else if (strstr(arch, "arm64_32") == arch || 
+             strstr(arch, "aarch64_32") == arch)
       return DNBArchProtocol::SetArchitecture(CPU_TYPE_ARM64_32);
     else if (strstr(arch, "arm64") == arch || strstr(arch, "armv8") == arch ||
              strstr(arch, "aarch64") == arch)
Index: lldb/unittests/Utility/ArchSpecTest.cpp
===================================================================
--- lldb/unittests/Utility/ArchSpecTest.cpp
+++ lldb/unittests/Utility/ArchSpecTest.cpp
@@ -157,8 +157,13 @@
     ArchSpec A("aarch64");
     ArchSpec B("aarch64--linux-android");
 
+    ArchSpec C("arm64_32");
+    ArchSpec D("arm64_32--watchos");
+
     EXPECT_TRUE(A.IsValid());
     EXPECT_TRUE(B.IsValid());
+    EXPECT_TRUE(C.IsValid());
+    EXPECT_TRUE(D.IsValid());
 
     EXPECT_EQ(llvm::Triple::ArchType::aarch64, B.GetTriple().getArch());
     EXPECT_EQ(llvm::Triple::VendorType::UnknownVendor,
@@ -174,6 +179,17 @@
     EXPECT_EQ(llvm::Triple::OSType::Linux, A.GetTriple().getOS());
     EXPECT_EQ(llvm::Triple::EnvironmentType::Android,
               A.GetTriple().getEnvironment());
+
+    EXPECT_EQ(llvm::Triple::ArchType::aarch64_32, D.GetTriple().getArch());
+    EXPECT_EQ(llvm::Triple::VendorType::UnknownVendor,
+              D.GetTriple().getVendor());
+    EXPECT_EQ(llvm::Triple::OSType::WatchOS, D.GetTriple().getOS());
+
+    C.MergeFrom(D);
+    EXPECT_EQ(llvm::Triple::ArchType::aarch64_32, C.GetTriple().getArch());
+    EXPECT_EQ(llvm::Triple::VendorType::UnknownVendor,
+              C.GetTriple().getVendor());
+    EXPECT_EQ(llvm::Triple::OSType::WatchOS, C.GetTriple().getOS());
   }
   {
     ArchSpec A, B;