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llvm-mirror/lib/Target/RISCV/RISCVFrameLowering.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

79 lines
3.2 KiB
C++

//===-- RISCVFrameLowering.h - Define frame lowering for RISCV -*- 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
//
//===----------------------------------------------------------------------===//
//
// This class implements RISCV-specific bits of TargetFrameLowering class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_RISCV_RISCVFRAMELOWERING_H
#define LLVM_LIB_TARGET_RISCV_RISCVFRAMELOWERING_H
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/Support/TypeSize.h"
namespace llvm {
class RISCVSubtarget;
class RISCVFrameLowering : public TargetFrameLowering {
public:
explicit RISCVFrameLowering(const RISCVSubtarget &STI)
: TargetFrameLowering(StackGrowsDown,
/*StackAlignment=*/Align(16),
/*LocalAreaOffset=*/0),
STI(STI) {}
void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
StackOffset getFrameIndexReference(const MachineFunction &MF, int FI,
Register &FrameReg) const override;
void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
RegScavenger *RS) const override;
void processFunctionBeforeFrameFinalized(MachineFunction &MF,
RegScavenger *RS) const override;
bool hasFP(const MachineFunction &MF) const override;
bool hasBP(const MachineFunction &MF) const;
bool hasReservedCallFrame(const MachineFunction &MF) const override;
MachineBasicBlock::iterator
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) 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;
// Get the first stack adjustment amount for SplitSPAdjust.
// Return 0 if we don't want to to split the SP adjustment in prologue and
// epilogue.
uint64_t getFirstSPAdjustAmount(const MachineFunction &MF) const;
bool canUseAsPrologue(const MachineBasicBlock &MBB) const override;
bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
protected:
const RISCVSubtarget &STI;
private:
void determineFrameLayout(MachineFunction &MF) const;
void adjustReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, Register DestReg, Register SrcReg,
int64_t Val, MachineInstr::MIFlag Flag) const;
};
}
#endif