Index: clang/lib/Headers/CMakeLists.txt
===================================================================
--- clang/lib/Headers/CMakeLists.txt
+++ clang/lib/Headers/CMakeLists.txt
@@ -46,6 +46,7 @@
   __clang_cuda_math_forward_declares.h
   __clang_cuda_runtime_wrapper.h
   cetintrin.h
+  cet.h
   cldemoteintrin.h
   clzerointrin.h
   cpuid.h
Index: clang/lib/Headers/cet.h
===================================================================
--- /dev/null
+++ clang/lib/Headers/cet.h
@@ -0,0 +1,57 @@
+/*===------ cet.h -Control-flow Enforcement Technology  feature ------------===
+ * Add x86 feature with IBT and/or SHSTK bits to ELF program property if they
+ * are enabled. Otherwise, contents in this header file are unused. This file
+ * is mainly design for assembly source code which want to enable CET.
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifdef __ASSEMBLER__
+
+#ifndef _CET_ENDBR
+# define _CET_ENDBR
+# ifdef __LP64__
+#  if __CET__ & 0x1
+#    define _CET_ENDBR endbr64
+#  endif
+# else
+#  if __CET__ & 0x1
+#    define _CET_ENDBR endbr32
+#  endif
+# endif
+#endif
+
+# ifdef __CET__
+
+#  ifdef __LP64__
+#   define __PROPERTY_ALIGN 3
+#  else
+#   define __PROPERTY_ALIGN 2
+#  endif
+
+	.pushsection ".note.gnu.property", "a"
+	.p2align __PROPERTY_ALIGN
+	.long 1f - 0f		/* name length.  */
+	.long 4f - 1f		/* data length.  */
+	/* NT_GNU_PROPERTY_TYPE_0.   */
+	.long 5			/* note type.  */
+0:
+	.asciz "GNU"		/* vendor name.  */
+1:
+	.p2align __PROPERTY_ALIGN
+	/* GNU_PROPERTY_X86_FEATURE_1_AND.  */
+	.long 0xc0000002	/* pr_type.  */
+	.long 3f - 2f		/* pr_datasz.  */
+2:
+	/* GNU_PROPERTY_X86_FEATURE_1_XXX.  */
+	.long __CET__
+3:
+	.p2align __PROPERTY_ALIGN
+4:
+	.popsection
+# endif
+#endif
Index: clang/test/CodeGen/asm-cet.S
===================================================================
--- /dev/null
+++ clang/test/CodeGen/asm-cet.S
@@ -0,0 +1,26 @@
+// RUN: %clang --target=x86_64-pc-linux -fcf-protection  -include cet.h -c %s -o - | llvm-readelf -n | FileCheck %s
+// RUN: %clang --target=x86_64-pc-linux -include cet.h -c %s -o - | llvm-readelf -S | FileCheck %s --check-prefixes=NOCET
+// RUN: %clang --target=x86_64-pc-linux -include cet.h -S %s -o - | FileCheck %s --check-prefixes=NOENDBR
+// RUN: %clang --target=x86_64-pc-linux -fcf-protection  -include cet.h -S %s -o - | FileCheck %s --check-prefixes=ENDBR64
+
+// RUN: %clang --target=i386-pc-linux -fcf-protection  -include cet.h -c %s -o - | llvm-readelf -n | FileCheck %s
+// RUN: %clang --target=i386-pc-linux -include cet.h -c %s -o - | llvm-readelf -S | FileCheck %s --check-prefixes=NOCET
+// RUN: %clang --target=i386-pc-linux -include cet.h -S %s -o - | FileCheck %s --check-prefixes=NOENDBR
+// RUN: %clang --target=i386-pc-linux -fcf-protection  -include cet.h -S %s -o - | FileCheck %s --check-prefixes=ENDBR32
+
+// CHECK: IBT, SHSTK
+
+// NOCET:     Section Headers
+// NOCET-NOT: .note.gnu.property
+
+// NOENDBR:   foo
+// NOENDBR-NOT: endbr
+
+// ENDBR64: endbr64
+// ENDBR32: endbr32
+        .text
+        .globl  foo
+        .type   foo, @function
+foo:
+        _CET_ENDBR
+        ret