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