Index: llvm/trunk/lib/CodeGen/XRayInstrumentation.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/XRayInstrumentation.cpp
+++ llvm/trunk/lib/CodeGen/XRayInstrumentation.cpp
@@ -95,10 +95,17 @@
 {
   for (auto &MBB : MF) {
     for (auto &T : MBB.terminators()) {
+      unsigned Opc = 0;
       if (T.isReturn()) {
-        // Prepend the return instruction with PATCHABLE_FUNCTION_EXIT
-        BuildMI(MBB, T, T.getDebugLoc(),
-                TII->get(TargetOpcode::PATCHABLE_FUNCTION_EXIT));
+        Opc = TargetOpcode::PATCHABLE_FUNCTION_EXIT;
+      }
+      if (TII->isTailCall(T)) {
+        Opc = TargetOpcode::PATCHABLE_TAIL_CALL;
+      }
+      if (Opc != 0) {
+        // Prepend the return instruction with PATCHABLE_FUNCTION_EXIT or
+        //   PATCHABLE_TAIL_CALL .
+        BuildMI(MBB, T, T.getDebugLoc(),TII->get(Opc));
       }
     }
   }
Index: llvm/trunk/lib/Target/ARM/ARMAsmPrinter.h
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMAsmPrinter.h
+++ llvm/trunk/lib/Target/ARM/ARMAsmPrinter.h
@@ -112,6 +112,7 @@
   // XRay-specific lowering for ARM.
   void LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI);
   void LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr &MI);
+  void LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI);
   // Helper function that emits the XRay sleds we've collected for a particular
   // function.
   void EmitXRayTable();
Index: llvm/trunk/lib/Target/ARM/ARMAsmPrinter.cpp
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMAsmPrinter.cpp
+++ llvm/trunk/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -2050,6 +2050,9 @@
   case ARM::PATCHABLE_FUNCTION_EXIT:
     LowerPATCHABLE_FUNCTION_EXIT(*MI);
     return;
+  case ARM::PATCHABLE_TAIL_CALL:
+    LowerPATCHABLE_TAIL_CALL(*MI);
+    return;
   }
 
   MCInst TmpInst;
Index: llvm/trunk/lib/Target/ARM/ARMMCInstLower.cpp
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMMCInstLower.cpp
+++ llvm/trunk/lib/Target/ARM/ARMMCInstLower.cpp
@@ -219,6 +219,11 @@
   EmitSled(MI, SledKind::FUNCTION_EXIT);
 }
 
+void ARMAsmPrinter::LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI)
+{
+  EmitSled(MI, SledKind::TAIL_CALL);
+}
+
 void ARMAsmPrinter::EmitXRayTable()
 {
   if (Sleds.empty())
Index: llvm/trunk/test/CodeGen/ARM/xray-tail-call-sled.ll
===================================================================
--- llvm/trunk/test/CodeGen/ARM/xray-tail-call-sled.ll
+++ llvm/trunk/test/CodeGen/ARM/xray-tail-call-sled.ll
@@ -0,0 +1,53 @@
+; RUN: llc -filetype=asm -o - -mtriple=armv7-unknown-linux-gnu < %s | FileCheck %s
+
+define i32 @callee() nounwind noinline uwtable "function-instrument"="xray-always" {
+; CHECK:       .p2align	2
+; CHECK-LABEL: Lxray_sled_0:
+; CHECK-NEXT:  b	#20
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-LABEL: Ltmp0:
+  ret i32 0
+; CHECK-NEXT:  mov	r0, #0
+; CHECK-NEXT:  .p2align	2
+; CHECK-LABEL: Lxray_sled_1:
+; CHECK-NEXT:  b	#20
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-LABEL: Ltmp1:
+; CHECK-NEXT:  bx	lr
+}
+
+define i32 @caller() nounwind noinline uwtable "function-instrument"="xray-always" {
+; CHECK:       .p2align	2
+; CHECK-LABEL: Lxray_sled_2:
+; CHECK-NEXT:  b	#20
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-LABEL: Ltmp2:
+; CHECK:       .p2align	2
+; CHECK-LABEL: Lxray_sled_3:
+; CHECK-NEXT:  b	#20
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-LABEL: Ltmp3:
+  %retval = tail call i32 @callee()
+; CHECK:       b	callee
+  ret i32 %retval
+}