MipsMCInstLower.cpp revision 239462 
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 "MipsMCInstLower.h"
16#include "MipsAsmPrinter.h"
17#include "MipsInstrInfo.h"
18#include "MCTargetDesc/MipsBaseInfo.h"
19#include "llvm/CodeGen/MachineFunction.h"
20#include "llvm/CodeGen/MachineInstr.h"
21#include "llvm/CodeGen/MachineOperand.h"
22#include "llvm/MC/MCContext.h"
23#include "llvm/MC/MCExpr.h"
24#include "llvm/MC/MCInst.h"
25#include "llvm/Target/Mangler.h"
26
27using namespace llvm;
28
29MipsMCInstLower::MipsMCInstLower(MipsAsmPrinter &asmprinter)
30  : AsmPrinter(asmprinter) {}
31
32void MipsMCInstLower::Initialize(Mangler *M, MCContext *C) {
33  Mang = M;
34  Ctx = C;
35}
36
37MCOperand MipsMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
38                                              MachineOperandType MOTy,
39                                              unsigned Offset) const {
40  MCSymbolRefExpr::VariantKind Kind;
41  const MCSymbol *Symbol;
42
43  switch(MO.getTargetFlags()) {
44  default:                   llvm_unreachable("Invalid target flag!");
45  case MipsII::MO_NO_FLAG:   Kind = MCSymbolRefExpr::VK_None; break;
46  case MipsII::MO_GPREL:     Kind = MCSymbolRefExpr::VK_Mips_GPREL; break;
47  case MipsII::MO_GOT_CALL:  Kind = MCSymbolRefExpr::VK_Mips_GOT_CALL; break;
48  case MipsII::MO_GOT16:     Kind = MCSymbolRefExpr::VK_Mips_GOT16; break;
49  case MipsII::MO_GOT:       Kind = MCSymbolRefExpr::VK_Mips_GOT; break;
50  case MipsII::MO_ABS_HI:    Kind = MCSymbolRefExpr::VK_Mips_ABS_HI; break;
51  case MipsII::MO_ABS_LO:    Kind = MCSymbolRefExpr::VK_Mips_ABS_LO; break;
52  case MipsII::MO_TLSGD:     Kind = MCSymbolRefExpr::VK_Mips_TLSGD; break;
53  case MipsII::MO_TLSLDM:    Kind = MCSymbolRefExpr::VK_Mips_TLSLDM; break;
54  case MipsII::MO_DTPREL_HI: Kind = MCSymbolRefExpr::VK_Mips_DTPREL_HI; break;
55  case MipsII::MO_DTPREL_LO: Kind = MCSymbolRefExpr::VK_Mips_DTPREL_LO; break;
56  case MipsII::MO_GOTTPREL:  Kind = MCSymbolRefExpr::VK_Mips_GOTTPREL; break;
57  case MipsII::MO_TPREL_HI:  Kind = MCSymbolRefExpr::VK_Mips_TPREL_HI; break;
58  case MipsII::MO_TPREL_LO:  Kind = MCSymbolRefExpr::VK_Mips_TPREL_LO; break;
59  case MipsII::MO_GPOFF_HI:  Kind = MCSymbolRefExpr::VK_Mips_GPOFF_HI; break;
60  case MipsII::MO_GPOFF_LO:  Kind = MCSymbolRefExpr::VK_Mips_GPOFF_LO; break;
61  case MipsII::MO_GOT_DISP:  Kind = MCSymbolRefExpr::VK_Mips_GOT_DISP; break;
62  case MipsII::MO_GOT_PAGE:  Kind = MCSymbolRefExpr::VK_Mips_GOT_PAGE; break;
63  case MipsII::MO_GOT_OFST:  Kind = MCSymbolRefExpr::VK_Mips_GOT_OFST; break;
64  case MipsII::MO_HIGHER:    Kind = MCSymbolRefExpr::VK_Mips_HIGHER; break;
65  case MipsII::MO_HIGHEST:   Kind = MCSymbolRefExpr::VK_Mips_HIGHEST; break;
66  }
67
68  switch (MOTy) {
69  case MachineOperand::MO_MachineBasicBlock:
70    Symbol = MO.getMBB()->getSymbol();
71    break;
72
73  case MachineOperand::MO_GlobalAddress:
74    Symbol = Mang->getSymbol(MO.getGlobal());
75    Offset += MO.getOffset();
76    break;
77
78  case MachineOperand::MO_BlockAddress:
79    Symbol = AsmPrinter.GetBlockAddressSymbol(MO.getBlockAddress());
80    Offset += MO.getOffset();
81    break;
82
83  case MachineOperand::MO_ExternalSymbol:
84    Symbol = AsmPrinter.GetExternalSymbolSymbol(MO.getSymbolName());
85    Offset += MO.getOffset();
86    break;
87
88  case MachineOperand::MO_JumpTableIndex:
89    Symbol = AsmPrinter.GetJTISymbol(MO.getIndex());
90    break;
91
92  case MachineOperand::MO_ConstantPoolIndex:
93    Symbol = AsmPrinter.GetCPISymbol(MO.getIndex());
94    Offset += MO.getOffset();
95    break;
96
97  default:
98    llvm_unreachable("<unknown operand type>");
99  }
100
101  const MCSymbolRefExpr *MCSym = MCSymbolRefExpr::Create(Symbol, Kind, *Ctx);
102
103  if (!Offset)
104    return MCOperand::CreateExpr(MCSym);
105
106  // Assume offset is never negative.
107  assert(Offset > 0);
108
109  const MCConstantExpr *OffsetExpr =  MCConstantExpr::Create(Offset, *Ctx);
110  const MCBinaryExpr *Add = MCBinaryExpr::CreateAdd(MCSym, OffsetExpr, *Ctx);
111  return MCOperand::CreateExpr(Add);
112}
113
114/*
115static void CreateMCInst(MCInst& Inst, unsigned Opc, const MCOperand &Opnd0,
116                         const MCOperand &Opnd1,
117                         const MCOperand &Opnd2 = MCOperand()) {
118  Inst.setOpcode(Opc);
119  Inst.addOperand(Opnd0);
120  Inst.addOperand(Opnd1);
121  if (Opnd2.isValid())
122    Inst.addOperand(Opnd2);
123}
124*/
125
126MCOperand MipsMCInstLower::LowerOperand(const MachineOperand &MO,
127                                        unsigned offset) const {
128  MachineOperandType MOTy = MO.getType();
129
130  switch (MOTy) {
131  default: llvm_unreachable("unknown operand type");
132  case MachineOperand::MO_Register:
133    // Ignore all implicit register operands.
134    if (MO.isImplicit()) break;
135    return MCOperand::CreateReg(MO.getReg());
136  case MachineOperand::MO_Immediate:
137    return MCOperand::CreateImm(MO.getImm() + offset);
138  case MachineOperand::MO_MachineBasicBlock:
139  case MachineOperand::MO_GlobalAddress:
140  case MachineOperand::MO_ExternalSymbol:
141  case MachineOperand::MO_JumpTableIndex:
142  case MachineOperand::MO_ConstantPoolIndex:
143  case MachineOperand::MO_BlockAddress:
144    return LowerSymbolOperand(MO, MOTy, offset);
145  case MachineOperand::MO_RegisterMask:
146    break;
147 }
148
149  return MCOperand();
150}
151
152void MipsMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
153  OutMI.setOpcode(MI->getOpcode());
154
155  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
156    const MachineOperand &MO = MI->getOperand(i);
157    MCOperand MCOp = LowerOperand(MO);
158
159    if (MCOp.isValid())
160      OutMI.addOperand(MCOp);
161  }
162}
163
164// If the D<shift> instruction has a shift amount that is greater
165// than 31 (checked in calling routine), lower it to a D<shift>32 instruction
166void MipsMCInstLower::LowerLargeShift(const MachineInstr *MI,
167                                      MCInst& Inst,
168                                      int64_t Shift) {
169  // rt
170  Inst.addOperand(LowerOperand(MI->getOperand(0)));
171  // rd
172  Inst.addOperand(LowerOperand(MI->getOperand(1)));
173  // saminus32
174  Inst.addOperand(MCOperand::CreateImm(Shift));
175
176  switch (MI->getOpcode()) {
177  default:
178    // Calling function is not synchronized
179    llvm_unreachable("Unexpected shift instruction");
180    break;
181  case Mips::DSLL:
182    Inst.setOpcode(Mips::DSLL32);
183    break;
184  case Mips::DSRL:
185    Inst.setOpcode(Mips::DSRL32);
186    break;
187  case Mips::DSRA:
188    Inst.setOpcode(Mips::DSRA32);
189    break;
190  }
191}
192