1//===-- SystemZMCInstLower.cpp - Lower 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#include "SystemZMCInstLower.h"
11#include "SystemZAsmPrinter.h"
12#include "llvm/IR/Mangler.h"
13#include "llvm/MC/MCExpr.h"
14#include "llvm/MC/MCInst.h"
15#include "llvm/MC/MCStreamer.h"
16
17using namespace llvm;
18
19// Return the VK_* enumeration for MachineOperand target flags Flags.
20static MCSymbolRefExpr::VariantKind getVariantKind(unsigned Flags) {
21  switch (Flags & SystemZII::MO_SYMBOL_MODIFIER) {
22    case 0:
23      return MCSymbolRefExpr::VK_None;
24    case SystemZII::MO_GOT:
25      return MCSymbolRefExpr::VK_GOT;
26    case SystemZII::MO_INDNTPOFF:
27      return MCSymbolRefExpr::VK_INDNTPOFF;
28  }
29  llvm_unreachable("Unrecognised MO_ACCESS_MODEL");
30}
31
32SystemZMCInstLower::SystemZMCInstLower(MCContext &ctx,
33                                       SystemZAsmPrinter &asmprinter)
34  : Ctx(ctx), AsmPrinter(asmprinter) {}
35
36const MCExpr *
37SystemZMCInstLower::getExpr(const MachineOperand &MO,
38                            MCSymbolRefExpr::VariantKind Kind) const {
39  const MCSymbol *Symbol;
40  bool HasOffset = true;
41  switch (MO.getType()) {
42  case MachineOperand::MO_MachineBasicBlock:
43    Symbol = MO.getMBB()->getSymbol();
44    HasOffset = false;
45    break;
46
47  case MachineOperand::MO_GlobalAddress:
48    Symbol = AsmPrinter.getSymbol(MO.getGlobal());
49    break;
50
51  case MachineOperand::MO_ExternalSymbol:
52    Symbol = AsmPrinter.GetExternalSymbolSymbol(MO.getSymbolName());
53    break;
54
55  case MachineOperand::MO_JumpTableIndex:
56    Symbol = AsmPrinter.GetJTISymbol(MO.getIndex());
57    HasOffset = false;
58    break;
59
60  case MachineOperand::MO_ConstantPoolIndex:
61    Symbol = AsmPrinter.GetCPISymbol(MO.getIndex());
62    break;
63
64  case MachineOperand::MO_BlockAddress:
65    Symbol = AsmPrinter.GetBlockAddressSymbol(MO.getBlockAddress());
66    break;
67
68  default:
69    llvm_unreachable("unknown operand type");
70  }
71  const MCExpr *Expr = MCSymbolRefExpr::create(Symbol, Kind, Ctx);
72  if (HasOffset)
73    if (int64_t Offset = MO.getOffset()) {
74      const MCExpr *OffsetExpr = MCConstantExpr::create(Offset, Ctx);
75      Expr = MCBinaryExpr::createAdd(Expr, OffsetExpr, Ctx);
76    }
77  return Expr;
78}
79
80MCOperand SystemZMCInstLower::lowerOperand(const MachineOperand &MO) const {
81  switch (MO.getType()) {
82  case MachineOperand::MO_Register:
83    return MCOperand::createReg(MO.getReg());
84
85  case MachineOperand::MO_Immediate:
86    return MCOperand::createImm(MO.getImm());
87
88  default: {
89    MCSymbolRefExpr::VariantKind Kind = getVariantKind(MO.getTargetFlags());
90    return MCOperand::createExpr(getExpr(MO, Kind));
91  }
92  }
93}
94
95void SystemZMCInstLower::lower(const MachineInstr *MI, MCInst &OutMI) const {
96  OutMI.setOpcode(MI->getOpcode());
97  for (unsigned I = 0, E = MI->getNumOperands(); I != E; ++I) {
98    const MachineOperand &MO = MI->getOperand(I);
99    // Ignore all implicit register operands.
100    if (!MO.isReg() || !MO.isImplicit())
101      OutMI.addOperand(lowerOperand(MO));
102  }
103}
104