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llvm-mirror/lib/Target/ARM/ARMFrameLowering.h
Sander de Smalen e0eda3654e [SVE] Return StackOffset for TargetFrameLowering::getFrameIndexReference.
To accommodate frame layouts that have both fixed and scalable objects
on the stack, describing a stack location or offset using a pointer + uint64_t
is not sufficient. For this reason, we've introduced the StackOffset class,
which models both the fixed- and scalable sized offsets.

The TargetFrameLowering::getFrameIndexReference is made to return a StackOffset,
so that this can be used in other interfaces, such as to eliminate frame indices
in PEI or to emit Debug locations for variables on the stack.

This patch is purely mechanical and doesn't change the behaviour of how
the result of this function is used for fixed-sized offsets. The patch adds
various checks to assert that the offset has no scalable component, as frame
offsets with a scalable component are not yet supported in various places.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D90018
2020-11-05 11:02:18 +00:00

101 lines
4.1 KiB
C++

//===- ARMTargetFrameLowering.h - Define frame lowering for ARM -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_ARM_ARMFRAMELOWERING_H
#define LLVM_LIB_TARGET_ARM_ARMFRAMELOWERING_H
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/Support/TypeSize.h"
namespace llvm {
class ARMSubtarget;
class CalleeSavedInfo;
class MachineFunction;
class ARMFrameLowering : public TargetFrameLowering {
protected:
const ARMSubtarget &STI;
public:
explicit ARMFrameLowering(const ARMSubtarget &sti);
/// emitProlog/emitEpilog - These methods insert prolog and epilog code into
/// the function.
void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
ArrayRef<CalleeSavedInfo> CSI,
const TargetRegisterInfo *TRI) const override;
bool
restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
MutableArrayRef<CalleeSavedInfo> CSI,
const TargetRegisterInfo *TRI) const override;
bool keepFramePointer(const MachineFunction &MF) const override;
bool enableCalleeSaveSkip(const MachineFunction &MF) const override;
bool hasFP(const MachineFunction &MF) const override;
bool hasReservedCallFrame(const MachineFunction &MF) const override;
bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
StackOffset getFrameIndexReference(const MachineFunction &MF, int FI,
Register &FrameReg) const override;
int ResolveFrameIndexReference(const MachineFunction &MF, int FI,
Register &FrameReg, int SPAdj) const;
void getCalleeSaves(const MachineFunction &MF,
BitVector &SavedRegs) const override;
void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
RegScavenger *RS) const override;
void adjustForSegmentedStacks(MachineFunction &MF,
MachineBasicBlock &MBB) const override;
/// Returns true if the target will correctly handle shrink wrapping.
bool enableShrinkWrapping(const MachineFunction &MF) const override;
bool isProfitableForNoCSROpt(const Function &F) const override {
// The no-CSR optimisation is bad for code size on ARM, because we can save
// many registers with a single PUSH/POP pair.
return false;
}
bool
assignCalleeSavedSpillSlots(MachineFunction &MF,
const TargetRegisterInfo *TRI,
std::vector<CalleeSavedInfo> &CSI) const override;
const SpillSlot *
getCalleeSavedSpillSlots(unsigned &NumEntries) const override;
private:
void emitPushInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
ArrayRef<CalleeSavedInfo> CSI, unsigned StmOpc,
unsigned StrOpc, bool NoGap, bool (*Func)(unsigned, bool),
unsigned NumAlignedDPRCS2Regs, unsigned MIFlags = 0) const;
void emitPopInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
MutableArrayRef<CalleeSavedInfo> CSI, unsigned LdmOpc,
unsigned LdrOpc, bool isVarArg, bool NoGap,
bool (*Func)(unsigned, bool),
unsigned NumAlignedDPRCS2Regs) const;
MachineBasicBlock::iterator
eliminateCallFramePseudoInstr(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) const override;
};
} // end namespace llvm
#endif // LLVM_LIB_TARGET_ARM_ARMFRAMELOWERING_H