diff --git a/llvm/lib/Target/X86/X86MCInstLower.cpp b/llvm/lib/Target/X86/X86MCInstLower.cpp
@@ -1035,9 +1035,11 @@ void X86AsmPrinter::LowerTlsAddr(X86MCInstLower &MCInstLowering,
 /// bytes.  Return the size of nop emitted.
 static unsigned EmitNop(MCStreamer &OS, unsigned NumBytes, bool Is64Bit,
                         const MCSubtargetInfo &STI) {
-  // This works only for 64bit. For 32bit we have to do additional checking if
-  // the CPU supports multi-byte nops.
-  assert(Is64Bit && "EmitNops only supports X86-64");
+  if (!Is64Bit) {
+    // TODO Do additional checking if the CPU supports multi-byte nops.
+    OS.EmitInstruction(MCInstBuilder(X86::NOOP), STI);
+    return 1;
+  }
 
   unsigned NopSize;
   unsigned Opc, BaseReg, ScaleVal, IndexReg, Displacement, SegmentReg;
@@ -1597,6 +1599,16 @@ void X86AsmPrinter::LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI,
 
   NoAutoPaddingScope NoPadScope(*OutStreamer);
 
+  const Function &F = MF->getFunction();
+  if (F.hasFnAttribute("patchable-function-entry")) {
+    unsigned Num;
+    if (F.getFnAttribute("patchable-function-entry")
+            .getValueAsString()
+            .getAsInteger(10, Num))
+      return;
+    EmitNops(*OutStreamer, Num, Subtarget->is64Bit(), getSubtargetInfo());
+    return;
+  }
   // We want to emit the following pattern:
   //
   //   .p2align 1, ...

diff --git a/llvm/test/CodeGen/AArch64/patchable-function-entry.ll b/llvm/test/CodeGen/AArch64/patchable-function-entry.ll
@@ -0,0 +1,55 @@
+; RUN: llc -mtriple=aarch64 %s -o - | FileCheck --check-prefixes=CHECK,NOFSECT %s
+; RUN: llc -mtriple=aarch64 -function-sections %s -o - | FileCheck --check-prefixes=CHECK,FSECT %s
+; RUN: llc -mtriple=aarch64 -no-integrated-as %s -o - | FileCheck --check-prefix=NOLINK %s
+
+; NOLINK-NOT: "awo"
+
+define i32 @f0() "patchable-function-entry"="0" {
+; CHECK-LABEL: f0:
+; CHECK-NEXT: .Lfunc_begin0:
+; CHECK-NOT:   nop
+; CHECK:       mov w0, wzr
+; CHECK:       .section __patchable_function_entries,"awo",@progbits,f0,unique,0
+; CHECK-NEXT:  .p2align 3
+; CHECK-NEXT:  .xword .Lfunc_begin0
+  ret i32 0
+}
+
+define i32 @f1() "patchable-function-entry"="1" {
+; CHECK-LABEL: f1:
+; CHECK-NEXT: .Lfunc_begin1:
+; CHECK:       nop
+; CHECK-NEXT:  mov w0, wzr
+; NOFSECT:     .section __patchable_function_entries,"awo",@progbits,f0,unique,0
+; FSECT:       .section __patchable_function_entries,"awo",@progbits,f1,unique,1
+; CHECK-NEXT:  .p2align 3
+; CHECK-NEXT:  .xword .Lfunc_begin1
+  ret i32 0
+}
+
+$f3 = comdat any
+define void @f3() "patchable-function-entry"="3" comdat {
+; CHECK-LABEL: f3:
+; CHECK-NEXT: .Lfunc_begin2:
+; CHECK-COUNT-3: nop
+; CHECK-NEXT:  ret
+; NOFSECT:     .section __patchable_function_entries,"aGwo",@progbits,f3,comdat,f3,unique,1
+; FSECT:       .section __patchable_function_entries,"aGwo",@progbits,f3,comdat,f3,unique,2
+; CHECK-NEXT:  .p2align 3
+; CHECK-NEXT:  .xword .Lfunc_begin2
+  ret void
+}
+
+$f5 = comdat any
+define void @f5() "patchable-function-entry"="5" comdat {
+; CHECK-LABEL: f5:
+; CHECK-NEXT: .Lfunc_begin3:
+; CHECK-COUNT-5: nop
+; CHECK-NEXT:  sub sp, sp, #16
+; NOFSECT      .section __patchable_function_entries,"aGwo",@progbits,f5,comdat,f5,unique,2
+; FSECT:       .section __patchable_function_entries,"aGwo",@progbits,f5,comdat,f5,unique,3
+; CHECK:       .p2align 3
+; CHECK-NEXT:  .xword .Lfunc_begin3
+  %frame = alloca i8, i32 16
+  ret void
+}
diff --git a/llvm/test/CodeGen/X86/patchable-function-entry.ll b/llvm/test/CodeGen/X86/patchable-function-entry.ll
@@ -0,0 +1,58 @@
+; RUN: llc -mtriple=i386 %s -o - | FileCheck --check-prefixes=CHECK,NOFSECT,32 %s
+; RUN: llc -mtriple=x86_64 %s -o - | FileCheck --check-prefixes=CHECK,NOFSECT,64 %s
+
+define void @f0() "patchable-function-entry"="0" {
+; CHECK-LABEL: f0:
+; CHECK-NEXT: .Lfunc_begin0:
+; CHECK-NOT:   nop
+; CHECK:       ret
+; CHECK:       .section __patchable_function_entries,"awo",@progbits,f0,unique,0
+; 32:          .p2align 2
+; 32-NEXT:     .long .Lfunc_begin0
+; 64:          .p2align 3
+; 64-NEXT:     .quad .Lfunc_begin0
+  ret void
+}
+
+define void @f1() "patchable-function-entry"="1" {
+; CHECK-LABEL: f1:
+; CHECK:       nop
+; CHECK-NEXT:  ret
+; NOFSECT:     .section __patchable_function_entries,"awo",@progbits,f0,unique,0
+; FSECT:       .section __patchable_function_entries,"awo",@progbits,f1,unique,1
+; 32:          .p2align 2
+; 32-NEXT:     .long .Lfunc_begin1
+; 64:          .p2align 3
+; 64-NEXT:     .quad .Lfunc_begin1
+  ret void
+}
+
+$f3 = comdat any
+define void @f3() "patchable-function-entry"="3" comdat {
+; CHECK-LABEL: f3:
+; 32-COUNT-3:  nop
+; 64:          nopl (%rax)
+; CHECK:       ret
+; NOFSECT:     .section __patchable_function_entries,"aGwo",@progbits,f3,comdat,f3,unique,1
+; FSECT:       .section __patchable_function_entries,"aGwo",@progbits,f3,comdat,f3,unique,2
+; 32:          .p2align 2
+; 32-NEXT:     .long .Lfunc_begin2
+; 64:          .p2align 3
+; 64-NEXT:     .quad .Lfunc_begin2
+  ret void
+}
+
+$f5 = comdat any
+define void @f5() "patchable-function-entry"="5" comdat {
+; CHECK-LABEL: f5:
+; 32-COUNT-5:  nop
+; 64:          nopl 8(%rax,%rax)
+; CHECK-NEXT:  ret
+; NOFSECT      .section __patchable_function_entries,"aGwo",@progbits,f5,comdat,f5,unique,2
+; FSECT:       .section __patchable_function_entries,"aGwo",@progbits,f5,comdat,f5,unique,3
+; 32:          .p2align 2
+; 32-NEXT:     .long .Lfunc_begin3
+; 64:          .p2align 3
+; 64-NEXT:     .quad .Lfunc_begin3
+  ret void
+}
diff --git a/llvm/test/Verifier/invalid-patchable-function-entry.ll b/llvm/test/Verifier/invalid-patchable-function-entry.ll
@@ -0,0 +1,11 @@
+; RUN: not llvm-as %s -o /dev/null 2>&1 | FileCheck %s
+
+; CHECK: "patchable-function-entry" takes an unsigned integer:
+; CHECK: "patchable-function-entry" takes an unsigned integer: a
+; CHECK: "patchable-function-entry" takes an unsigned integer: -1
+; CHECK: "patchable-function-entry" takes an unsigned integer: 3,
+
+define void @f() "patchable-function-entry" { ret void }
+define void @fa() "patchable-function-entry"="a" { ret void }
+define void @f_1() "patchable-function-entry"="-1" { ret void }
+define void @f3comma() "patchable-function-entry"="3," { ret void }