Use R0/R1 instead of R4/R5 for ARM eh_return return values

lib/Target/ARM/ARMBaseRegisterInfo.cpp

Index: lib/Target/ARM/ARMBaseRegisterInfo.cpp
diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index b673e9909ee43bcec457a5d0fa823d4645d57e8f..fce29e28b0c03b9c69317485fd4f60f23a5d97da 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -24,6 +24,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h" // @LOCALMOD
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/RegisterScavenging.h"
 #include "llvm/CodeGen/VirtRegMap.h"
@@ -63,7 +64,13 @@ static unsigned getFramePointerReg(const ARMSubtarget &STI) {
 const MCPhysReg*
 ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
   const ARMSubtarget &STI = MF->getSubtarget<ARMSubtarget>();
-  if (STI.isTargetNaCl()) return CSR_NaCl_SaveList; // @LOCALMOD
+  // @LOCALMOD-START

[jvoung (off chromium), 2015/06/03 17:19:38]

Leave a note that we aren't supporting the other CallingConvs?

Otherwise, this could be returned after the CallingConv checks like Darwin's
RegList.

[Derek Schuff, 2015/06/03 20:50:56]

Done.

+  if (STI.isTargetNaCl()) {
+    if (MF->getMMI().callsEHReturn())
+      return CSR_NaCl_EHRet_SaveList;
+    return CSR_NaCl_SaveList;
+  }
+  // @LOCALMOD-END
 
   const MCPhysReg *RegList =
       STI.isTargetDarwin() ? CSR_iOS_SaveList : CSR_AAPCS_SaveList;