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//===-- SystemZFrameLowering.h - Frame lowering for SystemZ -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef SYSTEMZFRAMELOWERING_H
#define SYSTEMZFRAMELOWERING_H
#include "SystemZSubtarget.h"
#include "llvm/ADT/IndexedMap.h"
#include "llvm/Target/TargetFrameLowering.h"
namespace llvm {
class SystemZTargetMachine;
class SystemZSubtarget;
class SystemZFrameLowering : public TargetFrameLowering {
IndexedMap<unsigned> RegSpillOffsets;
protected:
const SystemZTargetMachine &TM;
const SystemZSubtarget &STI;
public:
SystemZFrameLowering(const SystemZTargetMachine &tm,
const SystemZSubtarget &sti);
// Override FrameLowering.
virtual void
processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const LLVM_OVERRIDE;
virtual bool
spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const
LLVM_OVERRIDE;
virtual bool
restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBII,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const
LLVM_OVERRIDE;
virtual void emitPrologue(MachineFunction &MF) const LLVM_OVERRIDE;
virtual void emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const LLVM_OVERRIDE;
virtual bool hasFP(const MachineFunction &MF) const LLVM_OVERRIDE;
virtual int getFrameIndexOffset(const MachineFunction &MF,
int FI) const LLVM_OVERRIDE;
virtual bool hasReservedCallFrame(const MachineFunction &MF) const
LLVM_OVERRIDE;
virtual void
eliminateCallFramePseudoInstr(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) const
LLVM_OVERRIDE;
// The target-independent code automatically allocates save slots for
// call-saved GPRs. However, we don't need those slots for SystemZ,
// because the ABI sets aside GPR save slots in the caller-allocated part
// of the frame. Since the target-independent code puts this unneeded
// area at the top of the callee-allocated part of frame, we choose not
// to allocate it and adjust the offsets accordingly. Return the
// size of this unallocated area.
// FIXME: seems a bit hackish.
uint64_t getUnallocatedTopBytes(const MachineFunction &MF) const;
// Return the number of bytes in the callee-allocated part of the frame.
uint64_t getAllocatedStackSize(const MachineFunction &MF) const;
// Return the number of frame bytes that should be reserved for
// an emergency spill slot, for use by the register scaveneger.
// Return 0 if register scaveging won't be needed.
unsigned getEmergencySpillSlotSize(const MachineFunction &MF) const;
// Return the offset from the frame pointer of the emergency spill slot,
// which always fits within a 12-bit unsigned displacement field.
// Only valid if getEmergencySpillSlotSize(MF) returns nonzero.
unsigned getEmergencySpillSlotOffset(const MachineFunction &MF) const;
// Return the byte offset from the incoming stack pointer of Reg's
// ABI-defined save slot. Return 0 if no slot is defined for Reg.
unsigned getRegSpillOffset(unsigned Reg) const {
return RegSpillOffsets[Reg];
}
};
} // end namespace llvm
#endif
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