[Stackmaps] Make ithe frame-pointer required for stackmaps.

Do not eliminate the frame pointer if there is a stackmap or patchpoint in the
function. All stackmap references should be FP relative.

This fixes PR21107.

llvm-svn: 218920
diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
index f40744c..a7779d6 100644
--- a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -92,7 +92,8 @@
 #endif
 
   return (MFI->hasCalls() || MFI->hasVarSizedObjects() ||
-          MFI->isFrameAddressTaken());
+          MFI->isFrameAddressTaken() || MFI->hasStackMap() ||
+          MFI->hasPatchPoint());
 }
 
 /// hasReservedCallFrame - Under normal circumstances, when a frame pointer is