diff --git a/lldb/source/DataFormatters/FormatManager.cpp b/lldb/source/DataFormatters/FormatManager.cpp
--- a/lldb/source/DataFormatters/FormatManager.cpp
+++ b/lldb/source/DataFormatters/FormatManager.cpp
@@ -76,7 +76,7 @@
                   kNumFormats,
               "All formats must have a corresponding info entry.");
 
-static uint32_t g_num_format_infos = llvm::array_lengthof(g_format_infos);
+static uint32_t g_num_format_infos = std::size(g_format_infos);
 
 static bool GetFormatFromFormatChar(char format_char, Format &format) {
   for (uint32_t i = 0; i < g_num_format_infos; ++i) {
diff --git a/lldb/source/Host/posix/MainLoopPosix.cpp b/lldb/source/Host/posix/MainLoopPosix.cpp
--- a/lldb/source/Host/posix/MainLoopPosix.cpp
+++ b/lldb/source/Host/posix/MainLoopPosix.cpp
@@ -81,7 +81,7 @@
     EV_SET(&in_events[i++], fd.first, EVFILT_READ, EV_ADD, 0, 0, 0);
 
   num_events = kevent(loop.m_kqueue, in_events.data(), in_events.size(),
-                      out_events, llvm::array_lengthof(out_events), nullptr);
+                      out_events, std::size(out_events), nullptr);
 
   if (num_events < 0) {
     if (errno == EINTR) {
diff --git a/lldb/source/Host/windows/ConnectionGenericFileWindows.cpp b/lldb/source/Host/windows/ConnectionGenericFileWindows.cpp
--- a/lldb/source/Host/windows/ConnectionGenericFileWindows.cpp
+++ b/lldb/source/Host/windows/ConnectionGenericFileWindows.cpp
@@ -188,9 +188,8 @@
               ? std::chrono::duration_cast<std::chrono::milliseconds>(*timeout)
                     .count()
               : INFINITE;
-      DWORD wait_result =
-          ::WaitForMultipleObjects(llvm::array_lengthof(m_event_handles),
-                                   m_event_handles, FALSE, milliseconds);
+      DWORD wait_result = ::WaitForMultipleObjects(
+          std::size(m_event_handles), m_event_handles, FALSE, milliseconds);
       // All of the events are manual reset events, so make sure we reset them
       // to non-signalled.
       switch (wait_result) {
diff --git a/lldb/source/Interpreter/CommandInterpreter.cpp b/lldb/source/Interpreter/CommandInterpreter.cpp
--- a/lldb/source/Interpreter/CommandInterpreter.cpp
+++ b/lldb/source/Interpreter/CommandInterpreter.cpp
@@ -561,7 +561,7 @@
        "breakpoint set --name '%1'"}};
   // clang-format on
 
-  size_t num_regexes = llvm::array_lengthof(break_regexes);
+  size_t num_regexes = std::size(break_regexes);
 
   std::unique_ptr<CommandObjectRegexCommand> break_regex_cmd_up(
       new CommandObjectRegexCommand(
diff --git a/lldb/source/Plugins/ABI/ARM/ABIMacOSX_arm.cpp b/lldb/source/Plugins/ABI/ARM/ABIMacOSX_arm.cpp
--- a/lldb/source/Plugins/ABI/ARM/ABIMacOSX_arm.cpp
+++ b/lldb/source/Plugins/ABI/ARM/ABIMacOSX_arm.cpp
@@ -1186,8 +1186,7 @@
      nullptr,
      }};
 
-static const uint32_t k_num_register_infos =
-    llvm::array_lengthof(g_register_infos);
+static const uint32_t k_num_register_infos = std::size(g_register_infos);
 
 const lldb_private::RegisterInfo *
 ABIMacOSX_arm::GetRegisterInfoArray(uint32_t &count) {
@@ -1235,7 +1234,7 @@
 
   llvm::ArrayRef<addr_t>::iterator ai = args.begin(), ae = args.end();
 
-  for (size_t i = 0; i < llvm::array_lengthof(reg_names); ++i) {
+  for (size_t i = 0; i < std::size(reg_names); ++i) {
     if (ai == ae)
       break;
 
diff --git a/lldb/source/Plugins/ABI/ARM/ABISysV_arm.cpp b/lldb/source/Plugins/ABI/ARM/ABISysV_arm.cpp
--- a/lldb/source/Plugins/ABI/ARM/ABISysV_arm.cpp
+++ b/lldb/source/Plugins/ABI/ARM/ABISysV_arm.cpp
@@ -1189,8 +1189,7 @@
      nullptr,
      }};
 
-static const uint32_t k_num_register_infos =
-    llvm::array_lengthof(g_register_infos);
+static const uint32_t k_num_register_infos = std::size(g_register_infos);
 
 const lldb_private::RegisterInfo *
 ABISysV_arm::GetRegisterInfoArray(uint32_t &count) {
@@ -1240,7 +1239,7 @@
 
   llvm::ArrayRef<addr_t>::iterator ai = args.begin(), ae = args.end();
 
-  for (size_t i = 0; i < llvm::array_lengthof(reg_names); ++i) {
+  for (size_t i = 0; i < std::size(reg_names); ++i) {
     if (ai == ae)
       break;
 
diff --git a/lldb/source/Plugins/ABI/Mips/ABISysV_mips.cpp b/lldb/source/Plugins/ABI/Mips/ABISysV_mips.cpp
--- a/lldb/source/Plugins/ABI/Mips/ABISysV_mips.cpp
+++ b/lldb/source/Plugins/ABI/Mips/ABISysV_mips.cpp
@@ -503,8 +503,7 @@
     },
 };
 
-static const uint32_t k_num_register_infos =
-    llvm::array_lengthof(g_register_infos);
+static const uint32_t k_num_register_infos = std::size(g_register_infos);
 
 const lldb_private::RegisterInfo *
 ABISysV_mips::GetRegisterInfoArray(uint32_t &count) {
@@ -560,7 +559,7 @@
   llvm::ArrayRef<addr_t>::iterator ai = args.begin(), ae = args.end();
 
   // Write arguments to registers
-  for (size_t i = 0; i < llvm::array_lengthof(reg_names); ++i) {
+  for (size_t i = 0; i < std::size(reg_names); ++i) {
     if (ai == ae)
       break;
 
diff --git a/lldb/source/Plugins/ABI/Mips/ABISysV_mips64.cpp b/lldb/source/Plugins/ABI/Mips/ABISysV_mips64.cpp
--- a/lldb/source/Plugins/ABI/Mips/ABISysV_mips64.cpp
+++ b/lldb/source/Plugins/ABI/Mips/ABISysV_mips64.cpp
@@ -503,8 +503,7 @@
     },
 };
 
-static const uint32_t k_num_register_infos =
-    llvm::array_lengthof(g_register_infos_mips64);
+static const uint32_t k_num_register_infos = std::size(g_register_infos_mips64);
 
 const lldb_private::RegisterInfo *
 ABISysV_mips64::GetRegisterInfoArray(uint32_t &count) {
diff --git a/lldb/source/Plugins/ABI/PowerPC/ABISysV_ppc.cpp b/lldb/source/Plugins/ABI/PowerPC/ABISysV_ppc.cpp
--- a/lldb/source/Plugins/ABI/PowerPC/ABISysV_ppc.cpp
+++ b/lldb/source/Plugins/ABI/PowerPC/ABISysV_ppc.cpp
@@ -204,8 +204,7 @@
      nullptr,
      }};
 
-static const uint32_t k_num_register_infos =
-    llvm::array_lengthof(g_register_infos);
+static const uint32_t k_num_register_infos = std::size(g_register_infos);
 
 const lldb_private::RegisterInfo *
 ABISysV_ppc::GetRegisterInfoArray(uint32_t &count) {
diff --git a/lldb/source/Plugins/ABI/PowerPC/ABISysV_ppc64.cpp b/lldb/source/Plugins/ABI/PowerPC/ABISysV_ppc64.cpp
--- a/lldb/source/Plugins/ABI/PowerPC/ABISysV_ppc64.cpp
+++ b/lldb/source/Plugins/ABI/PowerPC/ABISysV_ppc64.cpp
@@ -53,10 +53,10 @@
 const lldb_private::RegisterInfo *
 ABISysV_ppc64::GetRegisterInfoArray(uint32_t &count) {
   if (GetByteOrder() == lldb::eByteOrderLittle) {
-    count = llvm::array_lengthof(g_register_infos_ppc64le);
+    count = std::size(g_register_infos_ppc64le);
     return g_register_infos_ppc64le;
   } else {
-    count = llvm::array_lengthof(g_register_infos_ppc64);
+    count = std::size(g_register_infos_ppc64);
     return g_register_infos_ppc64;
   }
 }
diff --git a/lldb/source/Plugins/ABI/SystemZ/ABISysV_s390x.cpp b/lldb/source/Plugins/ABI/SystemZ/ABISysV_s390x.cpp
--- a/lldb/source/Plugins/ABI/SystemZ/ABISysV_s390x.cpp
+++ b/lldb/source/Plugins/ABI/SystemZ/ABISysV_s390x.cpp
@@ -172,8 +172,7 @@
     DEFINE_REG(f15, 8, nullptr, LLDB_INVALID_REGNUM),
 };
 
-static const uint32_t k_num_register_infos =
-    llvm::array_lengthof(g_register_infos);
+static const uint32_t k_num_register_infos = std::size(g_register_infos);
 
 const lldb_private::RegisterInfo *
 ABISysV_s390x::GetRegisterInfoArray(uint32_t &count) {
diff --git a/lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp b/lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
--- a/lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
+++ b/lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
@@ -406,7 +406,7 @@
   const uint32_t magicks[] = { llvm::MachO::MH_MAGIC_64, llvm::MachO::MH_MAGIC, llvm::MachO::MH_CIGAM, llvm::MachO::MH_CIGAM_64};
 
   bool found_matching_pattern = false;
-  for (size_t i = 0; i < llvm::array_lengthof (magicks); i++)
+  for (size_t i = 0; i < std::size(magicks); i++)
     if (::memcmp (&header.magic, &magicks[i], sizeof (uint32_t)) == 0)
         found_matching_pattern = true;
 
diff --git a/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp b/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
--- a/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
+++ b/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
@@ -13188,7 +13188,7 @@
        &EmulateInstructionARM::EmulateRFE, "rfe{<amode>} <Rn>{!}"}
 
   };
-  static const size_t k_num_arm_opcodes = llvm::array_lengthof(g_arm_opcodes);
+  static const size_t k_num_arm_opcodes = std::size(g_arm_opcodes);
 
   for (size_t i = 0; i < k_num_arm_opcodes; ++i) {
     if ((g_arm_opcodes[i].mask & opcode) == g_arm_opcodes[i].value &&
@@ -13739,7 +13739,7 @@
        &EmulateInstructionARM::EmulateUXTH, "uxth<c>.w <Rd>,<Rm>{,<rotation>}"},
   };
 
-  const size_t k_num_thumb_opcodes = llvm::array_lengthof(g_thumb_opcodes);
+  const size_t k_num_thumb_opcodes = std::size(g_thumb_opcodes);
   for (size_t i = 0; i < k_num_thumb_opcodes; ++i) {
     if ((g_thumb_opcodes[i].mask & opcode) == g_thumb_opcodes[i].value &&
         (g_thumb_opcodes[i].variants & arm_isa) != 0)
diff --git a/lldb/source/Plugins/Instruction/ARM64/EmulateInstructionARM64.cpp b/lldb/source/Plugins/Instruction/ARM64/EmulateInstructionARM64.cpp
--- a/lldb/source/Plugins/Instruction/ARM64/EmulateInstructionARM64.cpp
+++ b/lldb/source/Plugins/Instruction/ARM64/EmulateInstructionARM64.cpp
@@ -52,7 +52,7 @@
 LLDB_PLUGIN_DEFINE_ADV(EmulateInstructionARM64, InstructionARM64)
 
 static bool LLDBTableGetRegisterInfo(uint32_t reg_num, RegisterInfo &reg_info) {
-  if (reg_num >= llvm::array_lengthof(g_register_infos_arm64_le))
+  if (reg_num >= std::size(g_register_infos_arm64_le))
     return false;
   reg_info = g_register_infos_arm64_le[reg_num];
   return true;
@@ -360,7 +360,7 @@
        "TBNZ <R><t>, #<imm>, <label>"},
 
   };
-  static const size_t k_num_arm_opcodes = llvm::array_lengthof(g_opcodes);
+  static const size_t k_num_arm_opcodes = std::size(g_opcodes);
 
   for (size_t i = 0; i < k_num_arm_opcodes; ++i) {
     if ((g_opcodes[i].mask & opcode) == g_opcodes[i].value)
diff --git a/lldb/source/Plugins/Instruction/PPC64/EmulateInstructionPPC64.cpp b/lldb/source/Plugins/Instruction/PPC64/EmulateInstructionPPC64.cpp
--- a/lldb/source/Plugins/Instruction/PPC64/EmulateInstructionPPC64.cpp
+++ b/lldb/source/Plugins/Instruction/PPC64/EmulateInstructionPPC64.cpp
@@ -59,7 +59,7 @@
 }
 
 static bool LLDBTableGetRegisterInfo(uint32_t reg_num, RegisterInfo &reg_info) {
-  if (reg_num >= llvm::array_lengthof(g_register_infos_ppc64le))
+  if (reg_num >= std::size(g_register_infos_ppc64le))
     return false;
   reg_info = g_register_infos_ppc64le[reg_num];
   return true;
@@ -147,7 +147,7 @@
        "addi RT, RA, SI"},
       {0xfc000003, 0xe8000000, &EmulateInstructionPPC64::EmulateLD,
        "ld RT, DS(RA)"}};
-  static const size_t k_num_ppc_opcodes = llvm::array_lengthof(g_opcodes);
+  static const size_t k_num_ppc_opcodes = std::size(g_opcodes);
 
   for (size_t i = 0; i < k_num_ppc_opcodes; ++i) {
     if ((g_opcodes[i].mask & opcode) == g_opcodes[i].value)
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp
@@ -656,7 +656,7 @@
   // array into a template table, and populate the DispatchFunction
   // map from there.
 
-  for (size_t i = 0; i != llvm::array_lengthof(g_dispatch_functions); i++) {
+  for (size_t i = 0; i != std::size(g_dispatch_functions); i++) {
     ConstString name_const_str(g_dispatch_functions[i].name);
     const Symbol *msgSend_symbol =
         m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str,
@@ -674,9 +674,9 @@
       m_msgSend_map.insert(std::pair<lldb::addr_t, int>(sym_addr, i));
     }
   }
-  
+
   // Similarly, cache the addresses of the "optimized dispatch" function.
-  for (size_t i = 0; i != llvm::array_lengthof(g_opt_dispatch_names); i++) {
+  for (size_t i = 0; i != std::size(g_opt_dispatch_names); i++) {
     ConstString name_const_str(g_opt_dispatch_names[i]);
     const Symbol *msgSend_symbol =
         m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str,
diff --git a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
--- a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
+++ b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
@@ -743,7 +743,7 @@
 }
 
 llvm::StringRef ObjectFilePECOFF::GetSectionName(const section_header_t &sect) {
-  llvm::StringRef hdr_name(sect.name, llvm::array_lengthof(sect.name));
+  llvm::StringRef hdr_name(sect.name, std::size(sect.name));
   hdr_name = hdr_name.split('\0').first;
   if (hdr_name.consume_front("/")) {
     lldb::offset_t stroff;
diff --git a/lldb/source/Plugins/ObjectFile/PECOFF/PECallFrameInfo.cpp b/lldb/source/Plugins/ObjectFile/PECOFF/PECallFrameInfo.cpp
--- a/lldb/source/Plugins/ObjectFile/PECOFF/PECallFrameInfo.cpp
+++ b/lldb/source/Plugins/ObjectFile/PECOFF/PECallFrameInfo.cpp
@@ -167,7 +167,7 @@
       lldb_r8_x86_64,  lldb_r9_x86_64,  lldb_r10_x86_64, lldb_r11_x86_64,
       lldb_r12_x86_64, lldb_r13_x86_64, lldb_r14_x86_64, lldb_r15_x86_64};
 
-  if (machine_reg >= llvm::array_lengthof(machine_to_lldb_register))
+  if (machine_reg >= std::size(machine_to_lldb_register))
     return LLDB_INVALID_REGNUM;
 
   return machine_to_lldb_register[machine_reg];
@@ -182,7 +182,7 @@
       lldb_xmm12_x86_64, lldb_xmm13_x86_64, lldb_xmm14_x86_64,
       lldb_xmm15_x86_64};
 
-  if (xmm_reg >= llvm::array_lengthof(xmm_to_lldb_register))
+  if (xmm_reg >= std::size(xmm_to_lldb_register))
     return LLDB_INVALID_REGNUM;
 
   return xmm_to_lldb_register[xmm_reg];
diff --git a/lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp b/lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
--- a/lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
+++ b/lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
@@ -652,7 +652,7 @@
                                        "libSystem.B.dylib"};
 
   FileSpecList bp_modules;
-  for (size_t i = 0; i < llvm::array_lengthof(g_bp_modules); i++) {
+  for (size_t i = 0; i < std::size(g_bp_modules); i++) {
     const char *bp_module = g_bp_modules[i];
     bp_modules.EmplaceBack(bp_module);
   }
@@ -661,9 +661,9 @@
   bool hardware = false;
   LazyBool skip_prologue = eLazyBoolNo;
   bp_sp = target.CreateBreakpoint(&bp_modules, nullptr, g_bp_names,
-                                  llvm::array_lengthof(g_bp_names),
-                                  eFunctionNameTypeFull, eLanguageTypeUnknown,
-                                  0, skip_prologue, internal, hardware);
+                                  std::size(g_bp_names), eFunctionNameTypeFull,
+                                  eLanguageTypeUnknown, 0, skip_prologue,
+                                  internal, hardware);
   bp_sp->SetBreakpointKind("thread-creation");
 
   return bp_sp;
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm.cpp
--- a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm.cpp
@@ -856,7 +856,7 @@
     exc_exception, exc_fsr, exc_far,
 };
 
-static size_t k_num_register_infos = llvm::array_lengthof(g_register_infos);
+static size_t k_num_register_infos = std::size(g_register_infos);
 
 RegisterContextDarwin_arm::RegisterContextDarwin_arm(
     Thread &thread, uint32_t concrete_frame_idx)
@@ -897,9 +897,9 @@
 }
 
 // Number of registers in each register set
-const size_t k_num_gpr_registers = llvm::array_lengthof(g_gpr_regnums);
-const size_t k_num_fpu_registers = llvm::array_lengthof(g_fpu_regnums);
-const size_t k_num_exc_registers = llvm::array_lengthof(g_exc_regnums);
+const size_t k_num_gpr_registers = std::size(g_gpr_regnums);
+const size_t k_num_fpu_registers = std::size(g_fpu_regnums);
+const size_t k_num_exc_registers = std::size(g_exc_regnums);
 
 // Register set definitions. The first definitions at register set index of
 // zero is for all registers, followed by other registers sets. The register
@@ -911,7 +911,7 @@
     {"Floating Point Registers", "fpu", k_num_fpu_registers, g_fpu_regnums},
     {"Exception State Registers", "exc", k_num_exc_registers, g_exc_regnums}};
 
-const size_t k_num_regsets = llvm::array_lengthof(g_reg_sets);
+const size_t k_num_regsets = std::size(g_reg_sets);
 
 size_t RegisterContextDarwin_arm::GetRegisterSetCount() {
   return k_num_regsets;
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm64.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm64.cpp
--- a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm64.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm64.cpp
@@ -90,8 +90,7 @@
 
 static uint32_t g_exc_regnums[] = {exc_far, exc_esr, exc_exception};
 
-static size_t k_num_register_infos =
-    llvm::array_lengthof(g_register_infos_arm64_le);
+static size_t k_num_register_infos = std::size(g_register_infos_arm64_le);
 
 RegisterContextDarwin_arm64::RegisterContextDarwin_arm64(
     Thread &thread, uint32_t concrete_frame_idx)
@@ -132,9 +131,9 @@
 }
 
 // Number of registers in each register set
-const size_t k_num_gpr_registers = llvm::array_lengthof(g_gpr_regnums);
-const size_t k_num_fpu_registers = llvm::array_lengthof(g_fpu_regnums);
-const size_t k_num_exc_registers = llvm::array_lengthof(g_exc_regnums);
+const size_t k_num_gpr_registers = std::size(g_gpr_regnums);
+const size_t k_num_fpu_registers = std::size(g_fpu_regnums);
+const size_t k_num_exc_registers = std::size(g_exc_regnums);
 
 // Register set definitions. The first definitions at register set index of
 // zero is for all registers, followed by other registers sets. The register
@@ -146,7 +145,7 @@
     {"Floating Point Registers", "fpu", k_num_fpu_registers, g_fpu_regnums},
     {"Exception State Registers", "exc", k_num_exc_registers, g_exc_regnums}};
 
-const size_t k_num_regsets = llvm::array_lengthof(g_reg_sets);
+const size_t k_num_regsets = std::size(g_reg_sets);
 
 size_t RegisterContextDarwin_arm64::GetRegisterSetCount() {
   return k_num_regsets;
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_i386.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_i386.cpp
--- a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_i386.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_i386.cpp
@@ -363,7 +363,7 @@
      nullptr,
      }};
 
-static size_t k_num_register_infos = llvm::array_lengthof(g_register_infos);
+static size_t k_num_register_infos = std::size(g_register_infos);
 
 RegisterContextDarwin_i386::RegisterContextDarwin_i386(
     Thread &thread, uint32_t concrete_frame_idx)
@@ -421,9 +421,9 @@
 static uint32_t g_exc_regnums[] = {exc_trapno, exc_err, exc_faultvaddr};
 
 // Number of registers in each register set
-const size_t k_num_gpr_registers = llvm::array_lengthof(g_gpr_regnums);
-const size_t k_num_fpu_registers = llvm::array_lengthof(g_fpu_regnums);
-const size_t k_num_exc_registers = llvm::array_lengthof(g_exc_regnums);
+const size_t k_num_gpr_registers = std::size(g_gpr_regnums);
+const size_t k_num_fpu_registers = std::size(g_fpu_regnums);
+const size_t k_num_exc_registers = std::size(g_exc_regnums);
 
 // Register set definitions. The first definitions at register set index of
 // zero is for all registers, followed by other registers sets. The register
@@ -435,7 +435,7 @@
     {"Floating Point Registers", "fpu", k_num_fpu_registers, g_fpu_regnums},
     {"Exception State Registers", "exc", k_num_exc_registers, g_exc_regnums}};
 
-const size_t k_num_regsets = llvm::array_lengthof(g_reg_sets);
+const size_t k_num_regsets = std::size(g_reg_sets);
 
 size_t RegisterContextDarwin_i386::GetRegisterSetCount() {
   return k_num_regsets;
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_x86_64.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_x86_64.cpp
--- a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_x86_64.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_x86_64.cpp
@@ -420,7 +420,7 @@
      nullptr,
      }};
 
-static size_t k_num_register_infos = llvm::array_lengthof(g_register_infos);
+static size_t k_num_register_infos = std::size(g_register_infos);
 
 RegisterContextDarwin_x86_64::RegisterContextDarwin_x86_64(
     Thread &thread, uint32_t concrete_frame_idx)
@@ -477,9 +477,9 @@
 static uint32_t g_exc_regnums[] = {exc_trapno, exc_err, exc_faultvaddr};
 
 // Number of registers in each register set
-const size_t k_num_gpr_registers = llvm::array_lengthof(g_gpr_regnums);
-const size_t k_num_fpu_registers = llvm::array_lengthof(g_fpu_regnums);
-const size_t k_num_exc_registers = llvm::array_lengthof(g_exc_regnums);
+const size_t k_num_gpr_registers = std::size(g_gpr_regnums);
+const size_t k_num_fpu_registers = std::size(g_fpu_regnums);
+const size_t k_num_exc_registers = std::size(g_exc_regnums);
 
 // Register set definitions. The first definitions at register set index of
 // zero is for all registers, followed by other registers sets. The register
@@ -491,7 +491,7 @@
     {"Floating Point Registers", "fpu", k_num_fpu_registers, g_fpu_regnums},
     {"Exception State Registers", "exc", k_num_exc_registers, g_exc_regnums}};
 
-const size_t k_num_regsets = llvm::array_lengthof(g_reg_sets);
+const size_t k_num_regsets = std::size(g_reg_sets);
 
 size_t RegisterContextDarwin_x86_64::GetRegisterSetCount() {
   return k_num_regsets;
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextWindows_i386.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextWindows_i386.cpp
--- a/lldb/source/Plugins/Process/Utility/RegisterContextWindows_i386.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextWindows_i386.cpp
@@ -78,11 +78,11 @@
 }
 
 uint32_t RegisterContextWindows_i386::GetRegisterCount() const {
-  return llvm::array_lengthof(g_register_infos_i386);
+  return std::size(g_register_infos_i386);
 }
 
 uint32_t RegisterContextWindows_i386::GetUserRegisterCount() const {
-  return llvm::array_lengthof(g_register_infos_i386);
+  return std::size(g_register_infos_i386);
 }
 
 size_t RegisterContextWindows_i386::GetGPRSize() const { return sizeof(GPR); }
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextWindows_x86_64.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextWindows_x86_64.cpp
--- a/lldb/source/Plugins/Process/Utility/RegisterContextWindows_x86_64.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextWindows_x86_64.cpp
@@ -141,11 +141,11 @@
 }
 
 uint32_t RegisterContextWindows_x86_64::GetRegisterCount() const {
-  return llvm::array_lengthof(g_register_infos_x86_64);
+  return std::size(g_register_infos_x86_64);
 }
 
 uint32_t RegisterContextWindows_x86_64::GetUserRegisterCount() const {
-  return llvm::array_lengthof(g_register_infos_x86_64);
+  return std::size(g_register_infos_x86_64);
 }
 
 size_t RegisterContextWindows_x86_64::GetGPRSize() const { return sizeof(GPR); }
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_WoW64.cpp b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_WoW64.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_WoW64.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_WoW64.cpp
@@ -37,8 +37,8 @@
 };
 
 static const RegisterSet g_reg_sets_WoW64[] = {
-    {"General Purpose Registers", "gpr",
-     llvm::array_lengthof(g_gpr_regnums_WoW64) - 1, g_gpr_regnums_WoW64},
+    {"General Purpose Registers", "gpr", std::size(g_gpr_regnums_WoW64) - 1,
+     g_gpr_regnums_WoW64},
 };
 enum { k_num_register_sets = 1 };
 
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_arm.cpp b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_arm.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_arm.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_arm.cpp
@@ -68,10 +68,10 @@
               "g_fpu_regnums_arm has wrong number of register infos");
 
 static const RegisterSet g_reg_sets_arm[] = {
-    {"General Purpose Registers", "gpr",
-     llvm::array_lengthof(g_gpr_regnums_arm) - 1, g_gpr_regnums_arm},
-    {"Floating Point Registers", "fpr",
-     llvm::array_lengthof(g_fpr_regnums_arm) - 1, g_fpr_regnums_arm},
+    {"General Purpose Registers", "gpr", std::size(g_gpr_regnums_arm) - 1,
+     g_gpr_regnums_arm},
+    {"Floating Point Registers", "fpr", std::size(g_fpr_regnums_arm) - 1,
+     g_fpr_regnums_arm},
 };
 
 enum { k_num_register_sets = 2 };
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_arm64.cpp b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_arm64.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_arm64.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_arm64.cpp
@@ -84,10 +84,10 @@
               "g_fpu_regnums_arm64 has wrong number of register infos");
 
 static const RegisterSet g_reg_sets_arm64[] = {
-    {"General Purpose Registers", "gpr",
-     llvm::array_lengthof(g_gpr_regnums_arm64) - 1, g_gpr_regnums_arm64},
-    {"Floating Point Registers", "fpr",
-     llvm::array_lengthof(g_fpr_regnums_arm64) - 1, g_fpr_regnums_arm64},
+    {"General Purpose Registers", "gpr", std::size(g_gpr_regnums_arm64) - 1,
+     g_gpr_regnums_arm64},
+    {"Floating Point Registers", "fpr", std::size(g_fpr_regnums_arm64) - 1,
+     g_fpr_regnums_arm64},
 };
 
 enum { k_num_register_sets = 2 };
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_i386.cpp b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_i386.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_i386.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_i386.cpp
@@ -37,8 +37,8 @@
 };
 
 static const RegisterSet g_reg_sets_i386[] = {
-    {"General Purpose Registers", "gpr",
-     llvm::array_lengthof(g_gpr_regnums_i386) - 1, g_gpr_regnums_i386},
+    {"General Purpose Registers", "gpr", std::size(g_gpr_regnums_i386) - 1,
+     g_gpr_regnums_i386},
 };
 
 enum { k_num_register_sets = 1 };
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_x86_64.cpp b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_x86_64.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_x86_64.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows_x86_64.cpp
@@ -48,10 +48,10 @@
 };
 
 static const RegisterSet g_reg_sets_x86_64[] = {
-    {"General Purpose Registers", "gpr",
-     llvm::array_lengthof(g_gpr_regnums_x86_64) - 1, g_gpr_regnums_x86_64},
-    {"Floating Point Registers", "fpr",
-     llvm::array_lengthof(g_fpr_regnums_x86_64) - 1, g_fpr_regnums_x86_64}};
+    {"General Purpose Registers", "gpr", std::size(g_gpr_regnums_x86_64) - 1,
+     g_gpr_regnums_x86_64},
+    {"Floating Point Registers", "fpr", std::size(g_fpr_regnums_x86_64) - 1,
+     g_fpr_regnums_x86_64}};
 
 enum { k_num_register_sets = 2 };
 
diff --git a/lldb/source/Plugins/Process/Windows/Common/arm/RegisterContextWindows_arm.cpp b/lldb/source/Plugins/Process/Windows/Common/arm/RegisterContextWindows_arm.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/arm/RegisterContextWindows_arm.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/arm/RegisterContextWindows_arm.cpp
@@ -41,7 +41,7 @@
 #include "Plugins/Process/Utility/RegisterInfos_arm.h"
 #undef DECLARE_REGISTER_INFOS_ARM_STRUCT
 
-static size_t k_num_register_infos = llvm::array_lengthof(g_register_infos_arm);
+static size_t k_num_register_infos = std::size(g_register_infos_arm);
 
 // Array of lldb register numbers used to define the set of all General Purpose
 // Registers
@@ -68,9 +68,9 @@
 };
 
 RegisterSet g_register_sets[] = {
-    {"General Purpose Registers", "gpr",
-     llvm::array_lengthof(g_gpr_reg_indices), g_gpr_reg_indices},
-    {"Floating Point Registers", "fpu", llvm::array_lengthof(g_fpu_reg_indices),
+    {"General Purpose Registers", "gpr", std::size(g_gpr_reg_indices),
+     g_gpr_reg_indices},
+    {"Floating Point Registers", "fpu", std::size(g_fpu_reg_indices),
      g_fpu_reg_indices},
 };
 
@@ -82,7 +82,7 @@
 RegisterContextWindows_arm::~RegisterContextWindows_arm() {}
 
 size_t RegisterContextWindows_arm::GetRegisterCount() {
-  return llvm::array_lengthof(g_register_infos_arm);
+  return std::size(g_register_infos_arm);
 }
 
 const RegisterInfo *
@@ -93,7 +93,7 @@
 }
 
 size_t RegisterContextWindows_arm::GetRegisterSetCount() {
-  return llvm::array_lengthof(g_register_sets);
+  return std::size(g_register_sets);
 }
 
 const RegisterSet *RegisterContextWindows_arm::GetRegisterSet(size_t reg_set) {
diff --git a/lldb/source/Plugins/Process/Windows/Common/arm64/RegisterContextWindows_arm64.cpp b/lldb/source/Plugins/Process/Windows/Common/arm64/RegisterContextWindows_arm64.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/arm64/RegisterContextWindows_arm64.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/arm64/RegisterContextWindows_arm64.cpp
@@ -44,8 +44,7 @@
 #include "Plugins/Process/Utility/RegisterInfos_arm64.h"
 #undef DECLARE_REGISTER_INFOS_ARM64_STRUCT
 
-static size_t k_num_register_infos =
-    llvm::array_lengthof(g_register_infos_arm64_le);
+static size_t k_num_register_infos = std::size(g_register_infos_arm64_le);
 
 // Array of lldb register numbers used to define the set of all General Purpose
 // Registers
@@ -82,9 +81,9 @@
 };
 
 RegisterSet g_register_sets[] = {
-    {"General Purpose Registers", "gpr",
-     llvm::array_lengthof(g_gpr_reg_indices), g_gpr_reg_indices},
-    {"Floating Point Registers", "fpu", llvm::array_lengthof(g_fpu_reg_indices),
+    {"General Purpose Registers", "gpr", std::size(g_gpr_reg_indices),
+     g_gpr_reg_indices},
+    {"Floating Point Registers", "fpu", std::size(g_fpu_reg_indices),
      g_fpu_reg_indices},
 };
 
@@ -96,7 +95,7 @@
 RegisterContextWindows_arm64::~RegisterContextWindows_arm64() {}
 
 size_t RegisterContextWindows_arm64::GetRegisterCount() {
-  return llvm::array_lengthof(g_register_infos_arm64_le);
+  return std::size(g_register_infos_arm64_le);
 }
 
 const RegisterInfo *
@@ -107,7 +106,7 @@
 }
 
 size_t RegisterContextWindows_arm64::GetRegisterSetCount() {
-  return llvm::array_lengthof(g_register_sets);
+  return std::size(g_register_sets);
 }
 
 const RegisterSet *
diff --git a/lldb/source/Plugins/Process/Windows/Common/x64/RegisterContextWindows_x64.cpp b/lldb/source/Plugins/Process/Windows/Common/x64/RegisterContextWindows_x64.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/x64/RegisterContextWindows_x64.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/x64/RegisterContextWindows_x64.cpp
@@ -262,7 +262,7 @@
     {DEFINE_FPU_XMM(xmm14)},
     {DEFINE_FPU_XMM(xmm15)}};
 
-static size_t k_num_register_infos = llvm::array_lengthof(g_register_infos);
+static size_t k_num_register_infos = std::size(g_register_infos);
 
 // Array of lldb register numbers used to define the set of all General Purpose
 // Registers
@@ -303,10 +303,10 @@
 };
 
 RegisterSet g_register_sets[] = {
-    {"General Purpose Registers", "gpr",
-     llvm::array_lengthof(g_gpr_reg_indices), g_gpr_reg_indices},
-    {"Floating Point Registers", "fpu",
-     llvm::array_lengthof(g_fpu_reg_indices), g_fpu_reg_indices}};
+    {"General Purpose Registers", "gpr", std::size(g_gpr_reg_indices),
+     g_gpr_reg_indices},
+    {"Floating Point Registers", "fpu", std::size(g_fpu_reg_indices),
+     g_fpu_reg_indices}};
 }
 
 // Constructors and Destructors
@@ -317,7 +317,7 @@
 RegisterContextWindows_x64::~RegisterContextWindows_x64() {}
 
 size_t RegisterContextWindows_x64::GetRegisterCount() {
-  return llvm::array_lengthof(g_register_infos);
+  return std::size(g_register_infos);
 }
 
 const RegisterInfo *
@@ -328,7 +328,7 @@
 }
 
 size_t RegisterContextWindows_x64::GetRegisterSetCount() {
-  return llvm::array_lengthof(g_register_sets);
+  return std::size(g_register_sets);
 }
 
 const RegisterSet *RegisterContextWindows_x64::GetRegisterSet(size_t reg_set) {
diff --git a/lldb/source/Plugins/Process/Windows/Common/x86/RegisterContextWindows_x86.cpp b/lldb/source/Plugins/Process/Windows/Common/x86/RegisterContextWindows_x86.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/x86/RegisterContextWindows_x86.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/x86/RegisterContextWindows_x86.cpp
@@ -118,7 +118,7 @@
      nullptr,
     },
 };
-static size_t k_num_register_infos = llvm::array_lengthof(g_register_infos);
+static size_t k_num_register_infos = std::size(g_register_infos);
 
 // Array of lldb register numbers used to define the set of all General Purpose
 // Registers
@@ -129,8 +129,8 @@
                                 eRegisterIndexEip, eRegisterIndexEflags};
 
 RegisterSet g_register_sets[] = {
-    {"General Purpose Registers", "gpr",
-     llvm::array_lengthof(g_gpr_reg_indices), g_gpr_reg_indices},
+    {"General Purpose Registers", "gpr", std::size(g_gpr_reg_indices),
+     g_gpr_reg_indices},
 };
 }
 
@@ -142,7 +142,7 @@
 RegisterContextWindows_x86::~RegisterContextWindows_x86() {}
 
 size_t RegisterContextWindows_x86::GetRegisterCount() {
-  return llvm::array_lengthof(g_register_infos);
+  return std::size(g_register_infos);
 }
 
 const RegisterInfo *
@@ -153,7 +153,7 @@
 }
 
 size_t RegisterContextWindows_x86::GetRegisterSetCount() {
-  return llvm::array_lengthof(g_register_sets);
+  return std::size(g_register_sets);
 }
 
 const RegisterSet *RegisterContextWindows_x86::GetRegisterSet(size_t reg_set) {
diff --git a/lldb/source/Plugins/Process/minidump/RegisterContextMinidump_ARM.cpp b/lldb/source/Plugins/Process/minidump/RegisterContextMinidump_ARM.cpp
--- a/lldb/source/Plugins/Process/minidump/RegisterContextMinidump_ARM.cpp
+++ b/lldb/source/Plugins/Process/minidump/RegisterContextMinidump_ARM.cpp
@@ -336,7 +336,7 @@
     DEF_Q(14),
     DEF_Q(15)};
 
-constexpr size_t k_num_reg_infos = llvm::array_lengthof(g_reg_infos);
+constexpr size_t k_num_reg_infos = std::size(g_reg_infos);
 
 // ARM general purpose registers.
 const uint32_t g_gpr_regnums[] = {
@@ -445,26 +445,26 @@
 };
 
 // Skip the last LLDB_INVALID_REGNUM in each count below by subtracting 1
-constexpr size_t k_num_gpr_regs = llvm::array_lengthof(g_gpr_regnums) - 1;
-constexpr size_t k_num_fpu_regs = llvm::array_lengthof(g_fpu_regnums) - 1;
+constexpr size_t k_num_gpr_regs = std::size(g_gpr_regnums) - 1;
+constexpr size_t k_num_fpu_regs = std::size(g_fpu_regnums) - 1;
 
 static RegisterSet g_reg_sets[] = {
     {"General Purpose Registers", "gpr", k_num_gpr_regs, g_gpr_regnums},
     {"Floating Point Registers", "fpu", k_num_fpu_regs, g_fpu_regnums},
 };
 
-constexpr size_t k_num_reg_sets = llvm::array_lengthof(g_reg_sets);
+constexpr size_t k_num_reg_sets = std::size(g_reg_sets);
 
 RegisterContextMinidump_ARM::RegisterContextMinidump_ARM(
     lldb_private::Thread &thread, const DataExtractor &data, bool apple)
     : RegisterContext(thread, 0), m_apple(apple) {
   lldb::offset_t offset = 0;
   m_regs.context_flags = data.GetU32(&offset);
-  for (unsigned i = 0; i < llvm::array_lengthof(m_regs.r); ++i)
+  for (unsigned i = 0; i < std::size(m_regs.r); ++i)
     m_regs.r[i] = data.GetU32(&offset);
   m_regs.cpsr = data.GetU32(&offset);
   m_regs.fpscr = data.GetU64(&offset);
-  for (unsigned i = 0; i < llvm::array_lengthof(m_regs.d); ++i)
+  for (unsigned i = 0; i < std::size(m_regs.d); ++i)
     m_regs.d[i] = data.GetU64(&offset);
   lldbassert(k_num_regs == k_num_reg_infos);
 }
diff --git a/lldb/source/Plugins/Process/minidump/RegisterContextMinidump_ARM64.cpp b/lldb/source/Plugins/Process/minidump/RegisterContextMinidump_ARM64.cpp
--- a/lldb/source/Plugins/Process/minidump/RegisterContextMinidump_ARM64.cpp
+++ b/lldb/source/Plugins/Process/minidump/RegisterContextMinidump_ARM64.cpp
@@ -544,7 +544,7 @@
     DEF_H(31),
 };
 
-constexpr size_t k_num_reg_infos = llvm::array_lengthof(g_reg_infos);
+constexpr size_t k_num_reg_infos = std::size(g_reg_infos);
 
 // ARM64 general purpose registers.
 const uint32_t g_gpr_regnums[] = {
@@ -751,15 +751,15 @@
 };
 
 // Skip the last LLDB_INVALID_REGNUM in each count below by subtracting 1
-constexpr size_t k_num_gpr_regs = llvm::array_lengthof(g_gpr_regnums) - 1;
-constexpr size_t k_num_fpu_regs = llvm::array_lengthof(g_fpu_regnums) - 1;
+constexpr size_t k_num_gpr_regs = std::size(g_gpr_regnums) - 1;
+constexpr size_t k_num_fpu_regs = std::size(g_fpu_regnums) - 1;
 
 static RegisterSet g_reg_sets[] = {
     {"General Purpose Registers", "gpr", k_num_gpr_regs, g_gpr_regnums},
     {"Floating Point Registers", "fpu", k_num_fpu_regs, g_fpu_regnums},
 };
 
-constexpr size_t k_num_reg_sets = llvm::array_lengthof(g_reg_sets);
+constexpr size_t k_num_reg_sets = std::size(g_reg_sets);
 
 RegisterContextMinidump_ARM64::RegisterContextMinidump_ARM64(
     lldb_private::Thread &thread, const DataExtractor &data)
diff --git a/lldb/source/Utility/ArchSpec.cpp b/lldb/source/Utility/ArchSpec.cpp
--- a/lldb/source/Utility/ArchSpec.cpp
+++ b/lldb/source/Utility/ArchSpec.cpp
@@ -340,9 +340,9 @@
     {ArchSpec::eCore_uknownMach64,    llvm::MachO::CPU_ARCH_ABI64,      0,                                      0xFF000000u, 0x00000000u}};
 // clang-format on
 
-static const ArchDefinition g_macho_arch_def = {
-    eArchTypeMachO, llvm::array_lengthof(g_macho_arch_entries),
-    g_macho_arch_entries, "mach-o"};
+static const ArchDefinition g_macho_arch_def = {eArchTypeMachO,
+                                                std::size(g_macho_arch_entries),
+                                                g_macho_arch_entries, "mach-o"};
 
 //===----------------------------------------------------------------------===//
 // A table that gets searched linearly for matches. This table is used to
@@ -410,7 +410,7 @@
 
 static const ArchDefinition g_elf_arch_def = {
     eArchTypeELF,
-    llvm::array_lengthof(g_elf_arch_entries),
+    std::size(g_elf_arch_entries),
     g_elf_arch_entries,
     "elf",
 };
@@ -436,7 +436,7 @@
 
 static const ArchDefinition g_coff_arch_def = {
     eArchTypeCOFF,
-    llvm::array_lengthof(g_coff_arch_entries),
+    std::size(g_coff_arch_entries),
     g_coff_arch_entries,
     "pe-coff",
 };
@@ -468,7 +468,7 @@
 }
 
 static inline const CoreDefinition *FindCoreDefinition(ArchSpec::Core core) {
-  if (core < llvm::array_lengthof(g_core_definitions))
+  if (core < std::size(g_core_definitions))
     return &g_core_definitions[core];
   return nullptr;
 }
diff --git a/lldb/unittests/Utility/StatusTest.cpp b/lldb/unittests/Utility/StatusTest.cpp
--- a/lldb/unittests/Utility/StatusTest.cpp
+++ b/lldb/unittests/Utility/StatusTest.cpp
@@ -72,7 +72,7 @@
   EXPECT_TRUE(success.Success());
 
   WCHAR name[128]{};
-  ULONG nameLen = llvm::array_lengthof(name);
+  ULONG nameLen = std::size(name);
   ULONG langs = 0;
   GetUserPreferredUILanguages(MUI_LANGUAGE_NAME, &langs,
                               reinterpret_cast<PZZWSTR>(&name), &nameLen);