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/IR/GlobalValue.h"
21#include "llvm/MC/MCAsmInfo.h"
22#include "llvm/MC/MCExpr.h"
23#include "llvm/MC/MCInst.h"
24#include "llvm/Target/Mangler.h"
25using namespace llvm;
26
27static MachineModuleInfoMachO &getMachOMMI(AsmPrinter &AP) {
28  return AP.MMI->getObjFileInfo<MachineModuleInfoMachO>();
29}
30
31
32static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO, AsmPrinter &AP){
33  MCContext &Ctx = AP.OutContext;
34
35  SmallString<128> Name;
36  if (!MO.isGlobal()) {
37    assert(MO.isSymbol() && "Isn't a symbol reference");
38    Name += AP.MAI->getGlobalPrefix();
39    Name += MO.getSymbolName();
40  } else {
41    const GlobalValue *GV = MO.getGlobal();
42    bool isImplicitlyPrivate = false;
43    if (MO.getTargetFlags() == PPCII::MO_DARWIN_STUB ||
44        (MO.getTargetFlags() & PPCII::MO_NLP_FLAG))
45      isImplicitlyPrivate = true;
46
47    AP.Mang->getNameWithPrefix(Name, GV, isImplicitlyPrivate);
48  }
49
50  // If the target flags on the operand changes the name of the symbol, do that
51  // before we return the symbol.
52  if (MO.getTargetFlags() == PPCII::MO_DARWIN_STUB) {
53    Name += "$stub";
54    MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
55    MachineModuleInfoImpl::StubValueTy &StubSym =
56      getMachOMMI(AP).getFnStubEntry(Sym);
57    if (StubSym.getPointer())
58      return Sym;
59
60    if (MO.isGlobal()) {
61      StubSym =
62      MachineModuleInfoImpl::
63      StubValueTy(AP.Mang->getSymbol(MO.getGlobal()),
64                  !MO.getGlobal()->hasInternalLinkage());
65    } else {
66      Name.erase(Name.end()-5, Name.end());
67      StubSym =
68      MachineModuleInfoImpl::
69      StubValueTy(Ctx.GetOrCreateSymbol(Name.str()), false);
70    }
71    return Sym;
72  }
73
74  // If the symbol reference is actually to a non_lazy_ptr, not to the symbol,
75  // then add the suffix.
76  if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG) {
77    Name += "$non_lazy_ptr";
78    MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
79
80    MachineModuleInfoMachO &MachO = getMachOMMI(AP);
81
82    MachineModuleInfoImpl::StubValueTy &StubSym =
83      (MO.getTargetFlags() & PPCII::MO_NLP_HIDDEN_FLAG) ?
84         MachO.getHiddenGVStubEntry(Sym) : MachO.getGVStubEntry(Sym);
85
86    if (StubSym.getPointer() == 0) {
87      assert(MO.isGlobal() && "Extern symbol not handled yet");
88      StubSym = MachineModuleInfoImpl::
89                   StubValueTy(AP.Mang->getSymbol(MO.getGlobal()),
90                               !MO.getGlobal()->hasInternalLinkage());
91    }
92    return Sym;
93  }
94
95  return Ctx.GetOrCreateSymbol(Name.str());
96}
97
98static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
99                              AsmPrinter &Printer, bool isDarwin) {
100  MCContext &Ctx = Printer.OutContext;
101  MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
102
103  unsigned access = MO.getTargetFlags() & PPCII::MO_ACCESS_MASK;
104
105  switch (access) {
106    case PPCII::MO_HA16: RefKind = isDarwin ?
107                           MCSymbolRefExpr::VK_PPC_DARWIN_HA16 :
108                           MCSymbolRefExpr::VK_PPC_GAS_HA16;
109                         break;
110    case PPCII::MO_LO16: RefKind = isDarwin ?
111                           MCSymbolRefExpr::VK_PPC_DARWIN_LO16 :
112                           MCSymbolRefExpr::VK_PPC_GAS_LO16;
113                         break;
114    case PPCII::MO_TPREL16_HA: RefKind = MCSymbolRefExpr::VK_PPC_TPREL16_HA;
115                               break;
116    case PPCII::MO_TPREL16_LO: RefKind = MCSymbolRefExpr::VK_PPC_TPREL16_LO;
117                               break;
118    case PPCII::MO_DTPREL16_LO: RefKind = MCSymbolRefExpr::VK_PPC_DTPREL16_LO;
119                                break;
120    case PPCII::MO_TLSLD16_LO: RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD16_LO;
121                               break;
122    case PPCII::MO_TOC16_LO: RefKind = MCSymbolRefExpr::VK_PPC_TOC16_LO;
123                             break;
124   }
125
126  // FIXME: This isn't right, but we don't have a good way to express this in
127  // the MC Level, see below.
128  if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG)
129    RefKind = MCSymbolRefExpr::VK_None;
130
131  const MCExpr *Expr = MCSymbolRefExpr::Create(Symbol, RefKind, Ctx);
132
133  if (!MO.isJTI() && MO.getOffset())
134    Expr = MCBinaryExpr::CreateAdd(Expr,
135                                   MCConstantExpr::Create(MO.getOffset(), Ctx),
136                                   Ctx);
137
138  // Subtract off the PIC base if required.
139  if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG) {
140    const MachineFunction *MF = MO.getParent()->getParent()->getParent();
141
142    const MCExpr *PB = MCSymbolRefExpr::Create(MF->getPICBaseSymbol(), Ctx);
143    Expr = MCBinaryExpr::CreateSub(Expr, PB, Ctx);
144    // FIXME: We have no way to make the result be VK_PPC_LO16/VK_PPC_HA16,
145    // since it is not a symbol!
146  }
147
148  return MCOperand::CreateExpr(Expr);
149}
150
151void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
152                                        AsmPrinter &AP, bool isDarwin) {
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
158    MCOperand MCOp;
159    switch (MO.getType()) {
160    default:
161      MI->dump();
162      llvm_unreachable("unknown operand type");
163    case MachineOperand::MO_Register:
164      assert(!MO.getSubReg() && "Subregs should be eliminated!");
165      MCOp = MCOperand::CreateReg(MO.getReg());
166      break;
167    case MachineOperand::MO_Immediate:
168      MCOp = MCOperand::CreateImm(MO.getImm());
169      break;
170    case MachineOperand::MO_MachineBasicBlock:
171      MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
172                                      MO.getMBB()->getSymbol(), AP.OutContext));
173      break;
174    case MachineOperand::MO_GlobalAddress:
175    case MachineOperand::MO_ExternalSymbol:
176      MCOp = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP, isDarwin);
177      break;
178    case MachineOperand::MO_JumpTableIndex:
179      MCOp = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP, isDarwin);
180      break;
181    case MachineOperand::MO_ConstantPoolIndex:
182      MCOp = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP, isDarwin);
183      break;
184    case MachineOperand::MO_BlockAddress:
185      MCOp = GetSymbolRef(MO,AP.GetBlockAddressSymbol(MO.getBlockAddress()),AP,
186                          isDarwin);
187      break;
188    case MachineOperand::MO_RegisterMask:
189      continue;
190    }
191
192    OutMI.addOperand(MCOp);
193  }
194}
195