ARMMCInstLower.cpp revision cd81d94322a39503e4a3e87b6ee03d4fcb3465fb 
1//===-- ARMMCInstLower.cpp - Convert ARM MachineInstr to an 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 ARM MachineInstrs to their corresponding
11// MCInst records.
12//
13//===----------------------------------------------------------------------===//
14
15#include "ARM.h"
16#include "ARMAsmPrinter.h"
17#include "MCTargetDesc/ARMBaseInfo.h"
18#include "MCTargetDesc/ARMMCExpr.h"
19#include "llvm/CodeGen/MachineBasicBlock.h"
20#include "llvm/IR/Constants.h"
21#include "llvm/IR/Mangler.h"
22#include "llvm/MC/MCExpr.h"
23#include "llvm/MC/MCInst.h"
24using namespace llvm;
25
26
27MCOperand ARMAsmPrinter::GetSymbolRef(const MachineOperand &MO,
28                                      const MCSymbol *Symbol) {
29  const MCExpr *Expr;
30  unsigned Option = MO.getTargetFlags() & ARMII::MO_OPTION_MASK;
31  switch (Option) {
32  default: {
33    Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None,
34                                   OutContext);
35    switch (Option) {
36    default: llvm_unreachable("Unknown target flag on symbol operand");
37    case ARMII::MO_NO_FLAG:
38      break;
39    case ARMII::MO_LO16:
40      Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None,
41                                     OutContext);
42      Expr = ARMMCExpr::CreateLower16(Expr, OutContext);
43      break;
44    case ARMII::MO_HI16:
45      Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None,
46                                     OutContext);
47      Expr = ARMMCExpr::CreateUpper16(Expr, OutContext);
48      break;
49    }
50    break;
51  }
52
53  case ARMII::MO_PLT:
54    Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_PLT,
55                                   OutContext);
56    break;
57  }
58
59  if (!MO.isJTI() && MO.getOffset())
60    Expr = MCBinaryExpr::CreateAdd(Expr,
61                                   MCConstantExpr::Create(MO.getOffset(),
62                                                          OutContext),
63                                   OutContext);
64  return MCOperand::CreateExpr(Expr);
65
66}
67
68bool ARMAsmPrinter::lowerOperand(const MachineOperand &MO,
69                                 MCOperand &MCOp) {
70  switch (MO.getType()) {
71  default: llvm_unreachable("unknown operand type");
72  case MachineOperand::MO_Register:
73    // Ignore all non-CPSR implicit register operands.
74    if (MO.isImplicit() && MO.getReg() != ARM::CPSR)
75      return false;
76    assert(!MO.getSubReg() && "Subregs should be eliminated!");
77    MCOp = MCOperand::CreateReg(MO.getReg());
78    break;
79  case MachineOperand::MO_Immediate:
80    MCOp = MCOperand::CreateImm(MO.getImm());
81    break;
82  case MachineOperand::MO_MachineBasicBlock:
83    MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
84        MO.getMBB()->getSymbol(), OutContext));
85    break;
86  case MachineOperand::MO_GlobalAddress: {
87    MCOp = GetSymbolRef(MO,
88                        GetARMGVSymbol(MO.getGlobal(), MO.getTargetFlags()));
89    break;
90  }
91  case MachineOperand::MO_ExternalSymbol:
92   MCOp = GetSymbolRef(MO,
93                        GetExternalSymbolSymbol(MO.getSymbolName()));
94    break;
95  case MachineOperand::MO_JumpTableIndex:
96    MCOp = GetSymbolRef(MO, GetJTISymbol(MO.getIndex()));
97    break;
98  case MachineOperand::MO_ConstantPoolIndex:
99    MCOp = GetSymbolRef(MO, GetCPISymbol(MO.getIndex()));
100    break;
101  case MachineOperand::MO_BlockAddress:
102    MCOp = GetSymbolRef(MO, GetBlockAddressSymbol(MO.getBlockAddress()));
103    break;
104  case MachineOperand::MO_FPImmediate: {
105    APFloat Val = MO.getFPImm()->getValueAPF();
106    bool ignored;
107    Val.convert(APFloat::IEEEdouble, APFloat::rmTowardZero, &ignored);
108    MCOp = MCOperand::CreateFPImm(Val.convertToDouble());
109    break;
110  }
111  case MachineOperand::MO_RegisterMask:
112    // Ignore call clobbers.
113    return false;
114  }
115  return true;
116}
117
118void llvm::LowerARMMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
119                                        ARMAsmPrinter &AP) {
120  OutMI.setOpcode(MI->getOpcode());
121
122  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
123    const MachineOperand &MO = MI->getOperand(i);
124
125    MCOperand MCOp;
126    if (AP.lowerOperand(MO, MCOp))
127      OutMI.addOperand(MCOp);
128  }
129}
130