Index: clang-tools-extra/pp-trace/PPTrace.cpp
===================================================================
--- clang-tools-extra/pp-trace/PPTrace.cpp
+++ clang-tools-extra/pp-trace/PPTrace.cpp
@@ -69,7 +69,7 @@
     cl::desc("Output trace to the given file name or '-' for stdout."),
     cl::cat(Cat));
 
-LLVM_ATTRIBUTE_NORETURN static void error(Twine Message) {
+[[noreturn]] static void error(Twine Message) {
   WithColor::error() << Message << '\n';
   exit(1);
 }
Index: clang/utils/TableGen/ClangDiagnosticsEmitter.cpp
===================================================================
--- clang/utils/TableGen/ClangDiagnosticsEmitter.cpp
+++ clang/utils/TableGen/ClangDiagnosticsEmitter.cpp
@@ -614,7 +614,7 @@
     return It->second.Root;
   }
 
-  LLVM_ATTRIBUTE_NORETURN void PrintFatalError(llvm::Twine const &Msg) const {
+  [[noreturn]] void PrintFatalError(llvm::Twine const &Msg) const {
     assert(EvaluatingRecord && "not evaluating a record?");
     llvm::PrintFatalError(EvaluatingRecord->getLoc(), Msg);
   }
Index: flang/include/flang/Optimizer/Support/FatalError.h
===================================================================
--- flang/include/flang/Optimizer/Support/FatalError.h
+++ flang/include/flang/Optimizer/Support/FatalError.h
@@ -20,8 +20,8 @@
 
 /// Fatal error reporting helper. Report a fatal error with a source location
 /// and immediately abort flang.
-LLVM_ATTRIBUTE_NORETURN inline void emitFatalError(mlir::Location loc,
-                                                   const llvm::Twine &message) {
+[[noreturn]] inline void emitFatalError(mlir::Location loc,
+                                        const llvm::Twine &message) {
   mlir::emitError(loc, message);
   llvm::report_fatal_error("aborting");
 }
Index: lldb/source/Host/posix/ProcessLauncherPosixFork.cpp
===================================================================
--- lldb/source/Host/posix/ProcessLauncherPosixFork.cpp
+++ lldb/source/Host/posix/ProcessLauncherPosixFork.cpp
@@ -20,8 +20,8 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
-#include <sstream>
 #include <csignal>
+#include <sstream>
 
 #ifdef __ANDROID__
 #include <android/api-level.h>
@@ -46,8 +46,7 @@
 #endif
 }
 
-static void LLVM_ATTRIBUTE_NORETURN ExitWithError(int error_fd,
-                                                  const char *operation) {
+[[noreturn]] static void ExitWithError(int error_fd, const char *operation) {
   int err = errno;
   llvm::raw_fd_ostream os(error_fd, true);
   os << operation << " failed: " << llvm::sys::StrError(err);
@@ -55,7 +54,8 @@
   _exit(1);
 }
 
-static void DisableASLRIfRequested(int error_fd, const ProcessLaunchInfo &info) {
+static void DisableASLRIfRequested(int error_fd,
+                                   const ProcessLaunchInfo &info) {
 #if defined(__linux__)
   if (info.GetFlags().Test(lldb::eLaunchFlagDisableASLR)) {
     const unsigned long personality_get_current = 0xffffffff;
@@ -72,8 +72,8 @@
 
 static void DupDescriptor(int error_fd, const FileSpec &file_spec, int fd,
                           int flags) {
-  int target_fd = llvm::sys::RetryAfterSignal(-1, ::open,
-      file_spec.GetCString(), flags, 0666);
+  int target_fd = llvm::sys::RetryAfterSignal(
+      -1, ::open, file_spec.GetCString(), flags, 0666);
 
   if (target_fd == -1)
     ExitWithError(error_fd, "DupDescriptor-open");
@@ -88,8 +88,8 @@
   return;
 }
 
-static void LLVM_ATTRIBUTE_NORETURN ChildFunc(int error_fd,
-                                              const ProcessLaunchInfo &info) {
+[[noreturn]] static void ChildFunc(int error_fd,
+                                   const ProcessLaunchInfo &info) {
   if (info.GetFlags().Test(eLaunchFlagLaunchInSeparateProcessGroup)) {
     if (setpgid(0, 0) != 0)
       ExitWithError(error_fd, "setpgid");
Index: lldb/source/Plugins/Process/Linux/SingleStepCheck.cpp
===================================================================
--- lldb/source/Plugins/Process/Linux/SingleStepCheck.cpp
+++ lldb/source/Plugins/Process/Linux/SingleStepCheck.cpp
@@ -29,7 +29,7 @@
 #if defined(__arm64__) || defined(__aarch64__)
 namespace {
 
-void LLVM_ATTRIBUTE_NORETURN Child() {
+[[noreturn]] void Child() {
   if (ptrace(PTRACE_TRACEME, 0, nullptr, nullptr) == -1)
     _exit(1);
 
Index: llvm/include/llvm/Support/Compiler.h
===================================================================
--- llvm/include/llvm/Support/Compiler.h
+++ llvm/include/llvm/Support/Compiler.h
@@ -242,12 +242,12 @@
 #define LLVM_ATTRIBUTE_ALWAYS_INLINE inline
 #endif
 
-#ifdef __GNUC__
-#define LLVM_ATTRIBUTE_NORETURN __attribute__((noreturn))
-#elif defined(_MSC_VER)
-#define LLVM_ATTRIBUTE_NORETURN __declspec(noreturn)
+// C++ has [[noreturn]]. We are going to remove this eventually, but for now
+// let's keep it
+#ifdef(__cplusplus)
+#define LLVM_ATTRIBUTE_NORETURN [[noreturn]]
 #else
-#define LLVM_ATTRIBUTE_NORETURN
+#define LLVM_ATTRIBUTE_NORETURN _Noreturn
 #endif
 
 #if __has_attribute(returns_nonnull) || LLVM_GNUC_PREREQ(4, 9, 0)