xref: /freebsd/contrib/llvm-project/llvm/lib/Target/NVPTX/NVPTXFrameLowering.cpp (revision 56b17de1e8360fe131d425de20b5e75ff3ea897c)
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 
25 using namespace llvm;
26 
27 NVPTXFrameLowering::NVPTXFrameLowering()
28     : TargetFrameLowering(TargetFrameLowering::StackGrowsUp, Align(8), 0) {}
29 
30 bool NVPTXFrameLowering::hasFP(const MachineFunction &MF) const { return true; }
31 
32 void 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
47     //   mov %SPL, %depot;
48     //   cvta.local %SP, %SPL;
49     // for local address accesses in MF.
50     bool Is64Bit =
51         static_cast<const NVPTXTargetMachine &>(MF.getTarget()).is64Bit();
52     unsigned CvtaLocalOpcode =
53         (Is64Bit ? NVPTX::cvta_local_64 : NVPTX::cvta_local);
54     unsigned MovDepotOpcode =
55         (Is64Bit ? NVPTX::MOV_DEPOT_ADDR_64 : NVPTX::MOV_DEPOT_ADDR);
56     if (!MR.use_empty(NRI->getFrameRegister(MF))) {
57       // If %SP is not used, do not bother emitting "cvta.local %SP, %SPL".
58       MBBI = BuildMI(MBB, MBBI, dl,
59                      MF.getSubtarget().getInstrInfo()->get(CvtaLocalOpcode),
60                      NRI->getFrameRegister(MF))
61                  .addReg(NRI->getFrameLocalRegister(MF));
62     }
63     if (!MR.use_empty(NRI->getFrameLocalRegister(MF))) {
64       BuildMI(MBB, MBBI, dl,
65               MF.getSubtarget().getInstrInfo()->get(MovDepotOpcode),
66               NRI->getFrameLocalRegister(MF))
67           .addImm(MF.getFunctionNumber());
68     }
69   }
70 }
71 
72 StackOffset
73 NVPTXFrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
74                                            Register &FrameReg) const {
75   const MachineFrameInfo &MFI = MF.getFrameInfo();
76   FrameReg = NVPTX::VRDepot;
77   return StackOffset::getFixed(MFI.getObjectOffset(FI) -
78                                getOffsetOfLocalArea());
79 }
80 
81 void NVPTXFrameLowering::emitEpilogue(MachineFunction &MF,
82                                       MachineBasicBlock &MBB) const {}
83 
84 // This function eliminates ADJCALLSTACKDOWN,
85 // ADJCALLSTACKUP pseudo instructions
86 MachineBasicBlock::iterator NVPTXFrameLowering::eliminateCallFramePseudoInstr(
87     MachineFunction &MF, MachineBasicBlock &MBB,
88     MachineBasicBlock::iterator I) const {
89   // Simply discard ADJCALLSTACKDOWN,
90   // ADJCALLSTACKUP instructions.
91   return MBB.erase(I);
92 }
93 
94 TargetFrameLowering::DwarfFrameBase
95 NVPTXFrameLowering::getDwarfFrameBase(const MachineFunction &MF) const {
96   DwarfFrameBase FrameBase;
97   FrameBase.Kind = DwarfFrameBase::CFA;
98   FrameBase.Location.Offset = 0;
99   return FrameBase;
100 }
101