MipsMCInstLower.cpp revision ce1a538ab5b7ae7e0ed48d18c02571280fe105aa 
1//===-- MipsMCInstLower.cpp - Convert Mips MachineInstr to MCInst ---------===//
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 code to lower Mips MachineInstrs to their corresponding
11// MCInst records.
12//
13//===----------------------------------------------------------------------===//
14
15#include "MipsAsmPrinter.h"
16#include "MipsInstrInfo.h"
17#include "MipsMCInstLower.h"
18#include "llvm/CodeGen/MachineFunction.h"
19#include "llvm/CodeGen/MachineInstr.h"
20#include "llvm/CodeGen/MachineOperand.h"
21#include "llvm/MC/MCContext.h"
22#include "llvm/MC/MCExpr.h"
23#include "llvm/MC/MCInst.h"
24#include "llvm/Target/Mangler.h"
25using namespace llvm;
26
27MipsMCInstLower::MipsMCInstLower(Mangler *mang, const MachineFunction &mf,
28                                 MipsAsmPrinter &asmprinter)
29  : Ctx(mf.getContext()), Mang(mang), AsmPrinter(asmprinter) {}
30
31MCOperand MipsMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
32                                              MachineOperandType MOTy,
33                                              unsigned Offset) const {
34  MCSymbolRefExpr::VariantKind Kind;
35  const MCSymbol *Symbol;
36
37  switch(MO.getTargetFlags()) {
38  default:                  assert(0 && "Invalid target flag!");
39  case MipsII::MO_NO_FLAG:  Kind = MCSymbolRefExpr::VK_None; break;
40  case MipsII::MO_GPREL:    Kind = MCSymbolRefExpr::VK_Mips_GPREL; break;
41  case MipsII::MO_GOT_CALL: Kind = MCSymbolRefExpr::VK_Mips_GOT_CALL; break;
42  case MipsII::MO_GOT:      Kind = MCSymbolRefExpr::VK_Mips_GOT; break;
43  case MipsII::MO_ABS_HI:   Kind = MCSymbolRefExpr::VK_Mips_ABS_HI; break;
44  case MipsII::MO_ABS_LO:   Kind = MCSymbolRefExpr::VK_Mips_ABS_LO; break;
45  case MipsII::MO_TLSGD:    Kind = MCSymbolRefExpr::VK_Mips_TLSGD; break;
46  case MipsII::MO_GOTTPREL: Kind = MCSymbolRefExpr::VK_Mips_GOTTPREL; break;
47  case MipsII::MO_TPREL_HI: Kind = MCSymbolRefExpr::VK_Mips_TPREL_HI; break;
48  case MipsII::MO_TPREL_LO: Kind = MCSymbolRefExpr::VK_Mips_TPREL_LO; break;
49  case MipsII::MO_GPOFF_HI: Kind = MCSymbolRefExpr::VK_Mips_GPOFF_HI; break;
50  case MipsII::MO_GPOFF_LO: Kind = MCSymbolRefExpr::VK_Mips_GPOFF_LO; break;
51  case MipsII::MO_GOT_DISP: Kind = MCSymbolRefExpr::VK_Mips_GOT_DISP; break;
52  case MipsII::MO_GOT_PAGE: Kind = MCSymbolRefExpr::VK_Mips_GOT_PAGE; break;
53  case MipsII::MO_GOT_OFST: Kind = MCSymbolRefExpr::VK_Mips_GOT_OFST; break;
54  }
55
56  switch (MOTy) {
57    case MachineOperand::MO_MachineBasicBlock:
58      Symbol = MO.getMBB()->getSymbol();
59      break;
60
61    case MachineOperand::MO_GlobalAddress:
62      Symbol = Mang->getSymbol(MO.getGlobal());
63      break;
64
65    case MachineOperand::MO_BlockAddress:
66      Symbol = AsmPrinter.GetBlockAddressSymbol(MO.getBlockAddress());
67      break;
68
69    case MachineOperand::MO_ExternalSymbol:
70      Symbol = AsmPrinter.GetExternalSymbolSymbol(MO.getSymbolName());
71      break;
72
73    case MachineOperand::MO_JumpTableIndex:
74      Symbol = AsmPrinter.GetJTISymbol(MO.getIndex());
75      break;
76
77    case MachineOperand::MO_ConstantPoolIndex:
78      Symbol = AsmPrinter.GetCPISymbol(MO.getIndex());
79      if (MO.getOffset())
80        Offset += MO.getOffset();
81      break;
82
83    default:
84      llvm_unreachable("<unknown operand type>");
85  }
86
87  const MCSymbolRefExpr *MCSym = MCSymbolRefExpr::Create(Symbol, Kind, Ctx);
88
89  if (!Offset)
90    return MCOperand::CreateExpr(MCSym);
91
92  // Assume offset is never negative.
93  assert(Offset > 0);
94
95  const MCConstantExpr *OffsetExpr =  MCConstantExpr::Create(Offset, Ctx);
96  const MCBinaryExpr *AddExpr = MCBinaryExpr::CreateAdd(MCSym, OffsetExpr, Ctx);
97  return MCOperand::CreateExpr(AddExpr);
98}
99
100// Lower ".cpload $reg" to
101//  "lui   $gp, %hi(_gp_disp)"
102//  "addiu $gp, $gp, %lo(_gp_disp)"
103//  "addu  $gp. $gp, $reg"
104void MipsMCInstLower::LowerCPLOAD(const MachineInstr *MI,
105                                  SmallVector<MCInst, 4>& MCInsts) {
106  MCInst Lui, Addiu, Addu;
107  StringRef SymName("_gp_disp");
108  const MCSymbol *Symbol = Ctx.GetOrCreateSymbol(SymName);
109  const MCSymbolRefExpr *MCSym;
110
111  // lui   $gp, %hi(_gp_disp)
112  Lui.setOpcode(Mips::LUi);
113  Lui.addOperand(MCOperand::CreateReg(Mips::GP));
114  MCSym = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_Mips_ABS_HI, Ctx);
115  Lui.addOperand(MCOperand::CreateExpr(MCSym));
116  MCInsts.push_back(Lui);
117
118  // addiu $gp, $gp, %lo(_gp_disp)
119  Addiu.setOpcode(Mips::ADDiu);
120  Addiu.addOperand(MCOperand::CreateReg(Mips::GP));
121  Addiu.addOperand(MCOperand::CreateReg(Mips::GP));
122  MCSym = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_Mips_ABS_LO, Ctx);
123  Addiu.addOperand(MCOperand::CreateExpr(MCSym));
124  MCInsts.push_back(Addiu);
125
126  // addu  $gp. $gp, $reg
127  Addu.setOpcode(Mips::ADDu);
128  Addu.addOperand(MCOperand::CreateReg(Mips::GP));
129  Addu.addOperand(MCOperand::CreateReg(Mips::GP));
130  const MachineOperand &MO = MI->getOperand(0);
131  assert(MO.isReg() && "CPLOAD's operand must be a register.");
132  Addu.addOperand(MCOperand::CreateReg(MO.getReg()));
133  MCInsts.push_back(Addu);
134}
135
136// Lower ".cprestore offset" to "sw $gp, offset($sp)".
137void MipsMCInstLower::LowerCPRESTORE(const MachineInstr *MI, MCInst &OutMI) {
138  OutMI.clear();
139  OutMI.setOpcode(Mips::SW);
140  OutMI.addOperand(MCOperand::CreateReg(Mips::GP));
141  OutMI.addOperand(MCOperand::CreateReg(Mips::SP));
142  const MachineOperand &MO = MI->getOperand(0);
143  assert(MO.isImm() && "CPRESTORE's operand must be an immediate.");
144  OutMI.addOperand(MCOperand::CreateImm(MO.getImm()));
145}
146
147
148MCOperand MipsMCInstLower::LowerOperand(const MachineOperand& MO) const {
149  MachineOperandType MOTy = MO.getType();
150
151  switch (MOTy) {
152  default:
153    assert(0 && "unknown operand type");
154    break;
155  case MachineOperand::MO_Register:
156    // Ignore all implicit register operands.
157    if (MO.isImplicit()) break;
158    return MCOperand::CreateReg(MO.getReg());
159  case MachineOperand::MO_Immediate:
160    return MCOperand::CreateImm(MO.getImm());
161  case MachineOperand::MO_MachineBasicBlock:
162  case MachineOperand::MO_GlobalAddress:
163  case MachineOperand::MO_ExternalSymbol:
164  case MachineOperand::MO_JumpTableIndex:
165  case MachineOperand::MO_ConstantPoolIndex:
166  case MachineOperand::MO_BlockAddress:
167    return LowerSymbolOperand(MO, MOTy, 0);
168 }
169
170  return MCOperand();
171}
172
173void MipsMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
174  OutMI.setOpcode(MI->getOpcode());
175
176  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
177    const MachineOperand &MO = MI->getOperand(i);
178    MCOperand MCOp = LowerOperand(MO);
179
180    if (MCOp.isValid())
181      OutMI.addOperand(MCOp);
182  }
183}
184