Darwin requires a frame pointer for all non-leaf functions to support correct

backtraces.

llvm-svn: 89562

1 files changed, 4 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index 19762ee5cfb..df458689733 100644
--- a/llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -222,6 +222,7 @@ BitVector ARMBaseRegisterInfo::getReservedRegs(const MachineFunction &MF) const
   BitVector Reserved(getNumRegs());
   Reserved.set(ARM::SP);
   Reserved.set(ARM::PC);
+  // FP is reserved on Darwin even if we're not using it in this function.
   if (STI.isTargetDarwin() || hasFP(MF))
     Reserved.set(FramePtr);
   // Some targets reserve R9.
@@ -239,6 +240,7 @@ bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF,
     return true;
   case ARM::R7:
   case ARM::R11:
+    // FP is reserved on Darwin even if we're not using it in this function.
     if (FramePtr == Reg && (STI.isTargetDarwin() || hasFP(MF)))
       return true;
     break;
@@ -492,7 +494,8 @@ static unsigned calculateMaxStackAlignment(const MachineFrameInfo *FFI) {
 ///
 bool ARMBaseRegisterInfo::hasFP(const MachineFunction &MF) const {
   const MachineFrameInfo *MFI = MF.getFrameInfo();
-  return (NoFramePointerElim ||
+  return ((STI.isTargetDarwin() && MFI->hasCalls()) ||
+          NoFramePointerElim ||
           needsStackRealignment(MF) ||
           MFI->hasVarSizedObjects() ||
           MFI->isFrameAddressTaken());