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