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 "MCTargetDesc/NVPTXBaseInfo.h"
15#include "NVPTX.h"
16#include "NVPTXRegisterInfo.h"
17#include "NVPTXSubtarget.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
24using namespace llvm;
25
26NVPTXFrameLowering::NVPTXFrameLowering()
27 : TargetFrameLowering(TargetFrameLowering::StackGrowsUp, Align(8), 0) {}
28
29bool NVPTXFrameLowering::hasFPImpl(const MachineFunction &MF) const {
30 return true;
31}
32
33void NVPTXFrameLowering::emitPrologue(MachineFunction &MF,
34 MachineBasicBlock &MBB) const {
35 if (MF.getFrameInfo().hasStackObjects()) {
36 assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
37 MachineBasicBlock::iterator MBBI = MBB.begin();
38 MachineRegisterInfo &MR = MF.getRegInfo();
39
40 const NVPTXRegisterInfo *NRI =
41 MF.getSubtarget<NVPTXSubtarget>().getRegisterInfo();
42
43 // This instruction really occurs before first instruction
44 // in the BB, so giving it no debug location.
45 DebugLoc dl = DebugLoc();
46
47 // Emits the %SPL depot move and, when %SP is used, cvta.local.
48 // Mixed-width targets widen %SPL before cvta.local.
49 const Register FrameReg = NRI->getFrameRegister(MF);
50 const Register FrameLocalReg = NRI->getFrameLocalRegister(MF);
51 const bool Is64Bit = FrameReg == NVPTX::VRFrame64;
52 const bool IsLocal64 = FrameLocalReg == NVPTX::VRFrameLocal64;
53 unsigned CvtaLocalOpcode =
54 (Is64Bit ? NVPTX::cvta_local_64 : NVPTX::cvta_local_32);
55 unsigned MovDepotOpcode =
56 (IsLocal64 ? NVPTX::MOV_DEPOT_ADDR_64 : NVPTX::MOV_DEPOT_ADDR);
57 if (!MR.use_empty(RegNo: FrameReg)) {
58 // If %SP is not used, do not bother emitting "cvta.local %SP, %SPL".
59 MBBI = BuildMI(BB&: MBB, I: MBBI, MIMD: dl,
60 MCID: MF.getSubtarget().getInstrInfo()->get(Opcode: CvtaLocalOpcode),
61 DestReg: FrameReg)
62 .addReg(RegNo: Is64Bit == IsLocal64 ? FrameLocalReg : FrameReg);
63 if (Is64Bit && !IsLocal64) {
64 // Widen %SPL before converting it to a generic pointer.
65 MBBI =
66 BuildMI(BB&: MBB, I: MBBI, MIMD: dl,
67 MCID: MF.getSubtarget().getInstrInfo()->get(Opcode: NVPTX::CVT_u64_u32),
68 DestReg: FrameReg)
69 .addReg(RegNo: FrameLocalReg)
70 .addImm(Val: NVPTX::PTXCvtMode::NONE);
71 }
72 }
73 if (!MR.use_empty(RegNo: FrameLocalReg)) {
74 BuildMI(BB&: MBB, I: MBBI, MIMD: dl,
75 MCID: MF.getSubtarget().getInstrInfo()->get(Opcode: MovDepotOpcode),
76 DestReg: FrameLocalReg)
77 .addImm(Val: MF.getFunctionNumber());
78 }
79 }
80}
81
82StackOffset
83NVPTXFrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
84 Register &FrameReg) const {
85 const MachineFrameInfo &MFI = MF.getFrameInfo();
86 FrameReg = NVPTX::VRDepot;
87 return StackOffset::getFixed(Fixed: MFI.getObjectOffset(ObjectIdx: FI) -
88 getOffsetOfLocalArea());
89}
90
91void NVPTXFrameLowering::emitEpilogue(MachineFunction &MF,
92 MachineBasicBlock &MBB) const {}
93
94// This function eliminates ADJCALLSTACKDOWN,
95// ADJCALLSTACKUP pseudo instructions
96MachineBasicBlock::iterator NVPTXFrameLowering::eliminateCallFramePseudoInstr(
97 MachineFunction &MF, MachineBasicBlock &MBB,
98 MachineBasicBlock::iterator I) const {
99 // Simply discard ADJCALLSTACKDOWN,
100 // ADJCALLSTACKUP instructions.
101 return MBB.erase(I);
102}
103
104TargetFrameLowering::DwarfFrameBase
105NVPTXFrameLowering::getDwarfFrameBase(const MachineFunction &MF) const {
106 DwarfFrameBase FrameBase;
107 FrameBase.Kind = DwarfFrameBase::CFA;
108 FrameBase.Location.Offset = 0;
109 return FrameBase;
110}
111