Add support for the ARM GHC calling convention, this patch was in 3.0,
but somehow managed to be dropped later.

Patch by Karel Gardas.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161226 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index 231bd26..9deb96e 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -62,8 +62,20 @@
 
 const uint16_t*
 ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
+  bool ghcCall = false;
+ 
+  if (MF) {
+    const Function *F = MF->getFunction();
+    ghcCall = (F ? F->getCallingConv() == CallingConv::GHC : false);
+  }
+ 
+  if (ghcCall) {
+      return CSR_GHC_SaveList;
+  }
+  else {
   return (STI.isTargetIOS() && !STI.isAAPCS_ABI())
     ? CSR_iOS_SaveList : CSR_AAPCS_SaveList;
+  }
 }
 
 const uint32_t*