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 "llvm/CodeGen/MachineFrameInfo.h"
18#include "llvm/CodeGen/MachineFunction.h"
19#include "llvm/CodeGen/MachineInstrBuilder.h"
20#include "llvm/CodeGen/MachineRegisterInfo.h"
21#include "llvm/CodeGen/TargetInstrInfo.h"
22
23using namespace llvm;
24
25NVPTXFrameLowering::NVPTXFrameLowering()
26 : TargetFrameLowering(TargetFrameLowering::StackGrowsUp, Align(8), 0) {}
27
28bool NVPTXFrameLowering::hasFPImpl(const MachineFunction &MF) const {
29 return true;
30}
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 MachineBasicBlock::iterator MBBI = MBB.begin();
37 MachineRegisterInfo &MR = MF.getRegInfo();
38
39 const NVPTXRegisterInfo *NRI =
40 MF.getSubtarget<NVPTXSubtarget>().getRegisterInfo();
41
42 // This instruction really occurs before first instruction
43 // in the BB, so giving it no debug location.
44 DebugLoc dl = DebugLoc();
45
46 // Emits the %SPL depot move and, when %SP is used, cvta.local.
47 // Mixed-width targets widen %SPL before cvta.local.
48 const Register FrameReg = NRI->getFrameRegister(MF);
49 const Register FrameLocalReg = NRI->getFrameLocalRegister(MF);
50 const bool Is64Bit = FrameReg == NVPTX::VRFrame64;
51 const bool IsLocal64 = FrameLocalReg == NVPTX::VRFrameLocal64;
52 unsigned CvtaLocalOpcode =
53 (Is64Bit ? NVPTX::cvta_local_64 : NVPTX::cvta_local_32);
54 unsigned MovDepotOpcode =
55 (IsLocal64 ? NVPTX::MOV_DEPOT_ADDR_64 : NVPTX::MOV_DEPOT_ADDR);
56 if (!MR.use_empty(RegNo: FrameReg)) {
57 // If %SP is not used, do not bother emitting "cvta.local %SP, %SPL".
58 MBBI = BuildMI(BB&: MBB, I: MBBI, MIMD: dl,
59 MCID: MF.getSubtarget().getInstrInfo()->get(Opcode: CvtaLocalOpcode),
60 DestReg: FrameReg)
61 .addReg(RegNo: Is64Bit == IsLocal64 ? FrameLocalReg : FrameReg);
62 if (Is64Bit && !IsLocal64) {
63 // Widen %SPL before converting it to a generic pointer.
64 MBBI =
65 BuildMI(BB&: MBB, I: MBBI, MIMD: dl,
66 MCID: MF.getSubtarget().getInstrInfo()->get(Opcode: NVPTX::CVT_u64_u32),
67 DestReg: FrameReg)
68 .addReg(RegNo: FrameLocalReg)
69 .addImm(Val: NVPTX::PTXCvtMode::NONE);
70 }
71 }
72 if (!MR.use_empty(RegNo: FrameLocalReg)) {
73 BuildMI(BB&: MBB, I: MBBI, MIMD: dl,
74 MCID: MF.getSubtarget().getInstrInfo()->get(Opcode: MovDepotOpcode),
75 DestReg: FrameLocalReg)
76 .addImm(Val: MF.getFunctionNumber());
77 }
78 }
79}
80
81StackOffset
82NVPTXFrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
83 Register &FrameReg) const {
84 const MachineFrameInfo &MFI = MF.getFrameInfo();
85 FrameReg = NVPTX::VRDepot;
86 return StackOffset::getFixed(Fixed: MFI.getObjectOffset(ObjectIdx: FI) -
87 getOffsetOfLocalArea());
88}
89
90void NVPTXFrameLowering::emitEpilogue(MachineFunction &MF,
91 MachineBasicBlock &MBB) const {}
92
93// This function eliminates ADJCALLSTACKDOWN,
94// ADJCALLSTACKUP pseudo instructions
95MachineBasicBlock::iterator NVPTXFrameLowering::eliminateCallFramePseudoInstr(
96 MachineFunction &MF, MachineBasicBlock &MBB,
97 MachineBasicBlock::iterator I) const {
98 // Simply discard ADJCALLSTACKDOWN,
99 // ADJCALLSTACKUP instructions.
100 return MBB.erase(I);
101}
102
103TargetFrameLowering::DwarfFrameBase
104NVPTXFrameLowering::getDwarfFrameBase(const MachineFunction &MF) const {
105 DwarfFrameBase FrameBase;
106 FrameBase.Kind = DwarfFrameBase::CFA;
107 FrameBase.Location.Offset = 0;
108 return FrameBase;
109}
110