1//=======- NVPTXFrameLowering.cpp - NVPTX Frame Information ---*- C++ -*-=====//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains the NVPTX implementation of TargetFrameLowering class.
10//
11//===----------------------------------------------------------------------===//
12
13#include "NVPTXFrameLowering.h"
14#include "NVPTX.h"
15#include "NVPTXRegisterInfo.h"
16#include "NVPTXSubtarget.h"
17#include "NVPTXTargetMachine.h"
18#include "llvm/CodeGen/MachineFrameInfo.h"
19#include "llvm/CodeGen/MachineFunction.h"
20#include "llvm/CodeGen/MachineInstrBuilder.h"
21#include "llvm/CodeGen/MachineRegisterInfo.h"
22#include "llvm/CodeGen/TargetInstrInfo.h"
23#include "llvm/MC/MachineLocation.h"
24
25using namespace llvm;
26
27NVPTXFrameLowering::NVPTXFrameLowering()
28    : TargetFrameLowering(TargetFrameLowering::StackGrowsUp, Align(8), 0) {}
29
30bool NVPTXFrameLowering::hasFP(const MachineFunction &MF) const { return true; }
31
32void NVPTXFrameLowering::emitPrologue(MachineFunction &MF,
33                                      MachineBasicBlock &MBB) const {
34  if (MF.getFrameInfo().hasStackObjects()) {
35    assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
36    MachineInstr *MI = &MBB.front();
37    MachineRegisterInfo &MR = MF.getRegInfo();
38
39    // This instruction really occurs before first instruction
40    // in the BB, so giving it no debug location.
41    DebugLoc dl = DebugLoc();
42
43    // Emits
44    //   mov %SPL, %depot;
45    //   cvta.local %SP, %SPL;
46    // for local address accesses in MF.
47    bool Is64Bit =
48        static_cast<const NVPTXTargetMachine &>(MF.getTarget()).is64Bit();
49    unsigned CvtaLocalOpcode =
50        (Is64Bit ? NVPTX::cvta_local_yes_64 : NVPTX::cvta_local_yes);
51    unsigned MovDepotOpcode =
52        (Is64Bit ? NVPTX::MOV_DEPOT_ADDR_64 : NVPTX::MOV_DEPOT_ADDR);
53    if (!MR.use_empty(NVPTX::VRFrame)) {
54      // If %SP is not used, do not bother emitting "cvta.local %SP, %SPL".
55      MI = BuildMI(MBB, MI, dl,
56                   MF.getSubtarget().getInstrInfo()->get(CvtaLocalOpcode),
57                   NVPTX::VRFrame)
58               .addReg(NVPTX::VRFrameLocal);
59    }
60    BuildMI(MBB, MI, dl, MF.getSubtarget().getInstrInfo()->get(MovDepotOpcode),
61            NVPTX::VRFrameLocal)
62        .addImm(MF.getFunctionNumber());
63  }
64}
65
66int NVPTXFrameLowering::getFrameIndexReference(const MachineFunction &MF,
67                                               int FI,
68                                               unsigned &FrameReg) const {
69  const MachineFrameInfo &MFI = MF.getFrameInfo();
70  FrameReg = NVPTX::VRDepot;
71  return MFI.getObjectOffset(FI) - getOffsetOfLocalArea();
72}
73
74void NVPTXFrameLowering::emitEpilogue(MachineFunction &MF,
75                                      MachineBasicBlock &MBB) const {}
76
77// This function eliminates ADJCALLSTACKDOWN,
78// ADJCALLSTACKUP pseudo instructions
79MachineBasicBlock::iterator NVPTXFrameLowering::eliminateCallFramePseudoInstr(
80    MachineFunction &MF, MachineBasicBlock &MBB,
81    MachineBasicBlock::iterator I) const {
82  // Simply discard ADJCALLSTACKDOWN,
83  // ADJCALLSTACKUP instructions.
84  return MBB.erase(I);
85}
86