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llvm-mirror/lib/Target/NVPTX/NVPTXFrameLowering.cpp
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

92 lines
3.4 KiB
C++

//=======- NVPTXFrameLowering.cpp - NVPTX Frame Information ---*- 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 file contains the NVPTX implementation of TargetFrameLowering class.
//
//===----------------------------------------------------------------------===//
#include "NVPTXFrameLowering.h"
#include "NVPTX.h"
#include "NVPTXRegisterInfo.h"
#include "NVPTXSubtarget.h"
#include "NVPTXTargetMachine.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/MC/MachineLocation.h"
using namespace llvm;
NVPTXFrameLowering::NVPTXFrameLowering()
: TargetFrameLowering(TargetFrameLowering::StackGrowsUp, Align(8), 0) {}
bool NVPTXFrameLowering::hasFP(const MachineFunction &MF) const { return true; }
void NVPTXFrameLowering::emitPrologue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
if (MF.getFrameInfo().hasStackObjects()) {
assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
MachineInstr *MI = &MBB.front();
MachineRegisterInfo &MR = MF.getRegInfo();
// This instruction really occurs before first instruction
// in the BB, so giving it no debug location.
DebugLoc dl = DebugLoc();
// Emits
// mov %SPL, %depot;
// cvta.local %SP, %SPL;
// for local address accesses in MF.
bool Is64Bit =
static_cast<const NVPTXTargetMachine &>(MF.getTarget()).is64Bit();
unsigned CvtaLocalOpcode =
(Is64Bit ? NVPTX::cvta_local_yes_64 : NVPTX::cvta_local_yes);
unsigned MovDepotOpcode =
(Is64Bit ? NVPTX::MOV_DEPOT_ADDR_64 : NVPTX::MOV_DEPOT_ADDR);
if (!MR.use_empty(NVPTX::VRFrame)) {
// If %SP is not used, do not bother emitting "cvta.local %SP, %SPL".
MI = BuildMI(MBB, MI, dl,
MF.getSubtarget().getInstrInfo()->get(CvtaLocalOpcode),
NVPTX::VRFrame)
.addReg(NVPTX::VRFrameLocal);
}
BuildMI(MBB, MI, dl, MF.getSubtarget().getInstrInfo()->get(MovDepotOpcode),
NVPTX::VRFrameLocal)
.addImm(MF.getFunctionNumber());
}
}
StackOffset
NVPTXFrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
Register &FrameReg) const {
const MachineFrameInfo &MFI = MF.getFrameInfo();
FrameReg = NVPTX::VRDepot;
return StackOffset::getFixed(MFI.getObjectOffset(FI) -
getOffsetOfLocalArea());
}
void NVPTXFrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {}
// This function eliminates ADJCALLSTACKDOWN,
// ADJCALLSTACKUP pseudo instructions
MachineBasicBlock::iterator NVPTXFrameLowering::eliminateCallFramePseudoInstr(
MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
// Simply discard ADJCALLSTACKDOWN,
// ADJCALLSTACKUP instructions.
return MBB.erase(I);
}
TargetFrameLowering::DwarfFrameBase
NVPTXFrameLowering::getDwarfFrameBase(const MachineFunction &MF) const {
return {DwarfFrameBase::CFA, {0}};
}