PPCMCInstLower.cpp revision dfebc4cc4c267f797e823b781d73586cc6fc49c5 
1//===-- PPCMCInstLower.cpp - Convert PPC 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 PPC MachineInstrs to their corresponding
11// MCInst records.
12//
13//===----------------------------------------------------------------------===//
14
15#include "PPC.h"
16#include "llvm/ADT/SmallString.h"
17#include "llvm/CodeGen/AsmPrinter.h"
18#include "llvm/CodeGen/MachineFunction.h"
19#include "llvm/CodeGen/MachineModuleInfoImpls.h"
20#include "llvm/MC/MCAsmInfo.h"
21#include "llvm/MC/MCExpr.h"
22#include "llvm/MC/MCInst.h"
23#include "llvm/Target/Mangler.h"
24using namespace llvm;
25
26static MachineModuleInfoMachO &getMachOMMI(AsmPrinter &AP) {
27  return AP.MMI->getObjFileInfo<MachineModuleInfoMachO>();
28}
29
30
31static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO, AsmPrinter &AP){
32  MCContext &Ctx = AP.OutContext;
33
34  SmallString<128> Name;
35  if (!MO.isGlobal()) {
36    assert(MO.isSymbol() && "Isn't a symbol reference");
37    Name += AP.MAI->getGlobalPrefix();
38    Name += MO.getSymbolName();
39  } else {
40    const GlobalValue *GV = MO.getGlobal();
41    bool isImplicitlyPrivate = false;
42    if (MO.getTargetFlags() == PPCII::MO_DARWIN_STUB ||
43        (MO.getTargetFlags() & PPCII::MO_NLP_FLAG))
44      isImplicitlyPrivate = true;
45
46    AP.Mang->getNameWithPrefix(Name, GV, isImplicitlyPrivate);
47  }
48
49  // If the target flags on the operand changes the name of the symbol, do that
50  // before we return the symbol.
51  if (MO.getTargetFlags() == PPCII::MO_DARWIN_STUB) {
52    Name += "$stub";
53    MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
54    MachineModuleInfoImpl::StubValueTy &StubSym =
55      getMachOMMI(AP).getFnStubEntry(Sym);
56    if (StubSym.getPointer())
57      return Sym;
58
59    if (MO.isGlobal()) {
60      StubSym =
61      MachineModuleInfoImpl::
62      StubValueTy(AP.Mang->getSymbol(MO.getGlobal()),
63                  !MO.getGlobal()->hasInternalLinkage());
64    } else {
65      Name.erase(Name.end()-5, Name.end());
66      StubSym =
67      MachineModuleInfoImpl::
68      StubValueTy(Ctx.GetOrCreateSymbol(Name.str()), false);
69    }
70    return Sym;
71  }
72
73  // If the symbol reference is actually to a non_lazy_ptr, not to the symbol,
74  // then add the suffix.
75  if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG) {
76    Name += "$non_lazy_ptr";
77    MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
78
79    MachineModuleInfoMachO &MachO = getMachOMMI(AP);
80
81    MachineModuleInfoImpl::StubValueTy &StubSym =
82      (MO.getTargetFlags() & PPCII::MO_NLP_HIDDEN_FLAG) ?
83         MachO.getHiddenGVStubEntry(Sym) : MachO.getGVStubEntry(Sym);
84
85    if (StubSym.getPointer() == 0) {
86      assert(MO.isGlobal() && "Extern symbol not handled yet");
87      StubSym = MachineModuleInfoImpl::
88                   StubValueTy(AP.Mang->getSymbol(MO.getGlobal()),
89                               !MO.getGlobal()->hasInternalLinkage());
90    }
91    return Sym;
92  }
93
94  return Ctx.GetOrCreateSymbol(Name.str());
95}
96
97static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
98                              AsmPrinter &Printer, bool isDarwin) {
99  MCContext &Ctx = Printer.OutContext;
100  MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
101
102  unsigned access = MO.getTargetFlags() & PPCII::MO_ACCESS_MASK;
103
104  switch (access) {
105    case PPCII::MO_HA16: RefKind = isDarwin ?
106                           MCSymbolRefExpr::VK_PPC_DARWIN_HA16 :
107                           MCSymbolRefExpr::VK_PPC_GAS_HA16;
108                         break;
109    case PPCII::MO_LO16: RefKind = isDarwin ?
110                           MCSymbolRefExpr::VK_PPC_DARWIN_LO16 :
111                           MCSymbolRefExpr::VK_PPC_GAS_LO16;
112                         break;
113    case PPCII::MO_TPREL16_HA: RefKind = MCSymbolRefExpr::VK_PPC_TPREL16_HA;
114                               break;
115    case PPCII::MO_TPREL16_LO: RefKind = MCSymbolRefExpr::VK_PPC_TPREL16_LO;
116                               break;
117   }
118
119  // FIXME: This isn't right, but we don't have a good way to express this in
120  // the MC Level, see below.
121  if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG)
122    RefKind = MCSymbolRefExpr::VK_None;
123
124  const MCExpr *Expr = MCSymbolRefExpr::Create(Symbol, RefKind, Ctx);
125
126  if (!MO.isJTI() && MO.getOffset())
127    Expr = MCBinaryExpr::CreateAdd(Expr,
128                                   MCConstantExpr::Create(MO.getOffset(), Ctx),
129                                   Ctx);
130
131  // Subtract off the PIC base if required.
132  if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG) {
133    const MachineFunction *MF = MO.getParent()->getParent()->getParent();
134
135    const MCExpr *PB = MCSymbolRefExpr::Create(MF->getPICBaseSymbol(), Ctx);
136    Expr = MCBinaryExpr::CreateSub(Expr, PB, Ctx);
137    // FIXME: We have no way to make the result be VK_PPC_LO16/VK_PPC_HA16,
138    // since it is not a symbol!
139  }
140
141  return MCOperand::CreateExpr(Expr);
142}
143
144void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
145                                        AsmPrinter &AP, bool isDarwin) {
146  OutMI.setOpcode(MI->getOpcode());
147
148  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
149    const MachineOperand &MO = MI->getOperand(i);
150
151    MCOperand MCOp;
152    switch (MO.getType()) {
153    default:
154      MI->dump();
155      llvm_unreachable("unknown operand type");
156    case MachineOperand::MO_Register:
157      assert(!MO.getSubReg() && "Subregs should be eliminated!");
158      MCOp = MCOperand::CreateReg(MO.getReg());
159      break;
160    case MachineOperand::MO_Immediate:
161      MCOp = MCOperand::CreateImm(MO.getImm());
162      break;
163    case MachineOperand::MO_MachineBasicBlock:
164      MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
165                                      MO.getMBB()->getSymbol(), AP.OutContext));
166      break;
167    case MachineOperand::MO_GlobalAddress:
168    case MachineOperand::MO_ExternalSymbol:
169      MCOp = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP, isDarwin);
170      break;
171    case MachineOperand::MO_JumpTableIndex:
172      MCOp = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP, isDarwin);
173      break;
174    case MachineOperand::MO_ConstantPoolIndex:
175      MCOp = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP, isDarwin);
176      break;
177    case MachineOperand::MO_BlockAddress:
178      MCOp = GetSymbolRef(MO,AP.GetBlockAddressSymbol(MO.getBlockAddress()),AP,
179                          isDarwin);
180      break;
181    case MachineOperand::MO_RegisterMask:
182      continue;
183    }
184
185    OutMI.addOperand(MCOp);
186  }
187}
188