ARM implement TargetInstrInfo::getNoopForMachoTarget()

Without this hook, functions w/ a completely empty body (including no
epilogue) will cause an MCEmitter assertion failure.

For example,
define internal fastcc void @empty_function() {
  unreachable
}

rdar://10947471

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151673 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 1 deletions

diff --git a/lib/Target/ARM/Thumb1InstrInfo.cpp b/lib/Target/ARM/Thumb1InstrInfo.cpp
index ba16db3..adaccdd 100644
--- a/lib/Target/ARM/Thumb1InstrInfo.cpp
+++ b/lib/Target/ARM/Thumb1InstrInfo.cpp
@@ -19,7 +19,7 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/ADT/SmallVector.h"
-#include "Thumb1InstrInfo.h"
+#include "llvm/MC/MCInst.h"
 
 using namespace llvm;
 
@@ -27,6 +27,15 @@ Thumb1InstrInfo::Thumb1InstrInfo(const ARMSubtarget &STI)
   : ARMBaseInstrInfo(STI), RI(*this, STI) {
 }
 
+/// getNoopForMachoTarget - Return the noop instruction to use for a noop.
+void Thumb1InstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
+  NopInst.setOpcode(ARM::tMOVr);
+  NopInst.addOperand(MCOperand::CreateReg(ARM::R8));
+  NopInst.addOperand(MCOperand::CreateReg(ARM::R8));
+  NopInst.addOperand(MCOperand::CreateImm(ARMCC::AL));
+  NopInst.addOperand(MCOperand::CreateReg(0));
+}
+
 unsigned Thumb1InstrInfo::getUnindexedOpcode(unsigned Opc) const {
   return 0;
 }