PPCMCInstLower.cpp revision 360784 
1//===-- PPCMCInstLower.cpp - Convert PPC MachineInstr to an MCInst --------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains code to lower PPC MachineInstrs to their corresponding
10// MCInst records.
11//
12//===----------------------------------------------------------------------===//
13
14#include "MCTargetDesc/PPCMCExpr.h"
15#include "PPC.h"
16#include "PPCSubtarget.h"
17#include "llvm/ADT/SmallString.h"
18#include "llvm/ADT/Twine.h"
19#include "llvm/CodeGen/AsmPrinter.h"
20#include "llvm/CodeGen/MachineFunction.h"
21#include "llvm/CodeGen/MachineModuleInfoImpls.h"
22#include "llvm/CodeGen/TargetLowering.h"
23#include "llvm/IR/DataLayout.h"
24#include "llvm/IR/GlobalValue.h"
25#include "llvm/IR/Mangler.h"
26#include "llvm/MC/MCAsmInfo.h"
27#include "llvm/MC/MCExpr.h"
28#include "llvm/MC/MCInst.h"
29#include "llvm/Target/TargetLoweringObjectFile.h"
30using namespace llvm;
31
32static MachineModuleInfoMachO &getMachOMMI(AsmPrinter &AP) {
33  return AP.MMI->getObjFileInfo<MachineModuleInfoMachO>();
34}
35
36static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO,
37                                      AsmPrinter &AP) {
38  const TargetMachine &TM = AP.TM;
39  Mangler &Mang = TM.getObjFileLowering()->getMangler();
40  const DataLayout &DL = AP.getDataLayout();
41  MCContext &Ctx = AP.OutContext;
42
43  SmallString<128> Name;
44  StringRef Suffix;
45  if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG)
46    Suffix = "$non_lazy_ptr";
47
48  if (!Suffix.empty())
49    Name += DL.getPrivateGlobalPrefix();
50
51  if (!MO.isGlobal()) {
52    assert(MO.isSymbol() && "Isn't a symbol reference");
53    Mangler::getNameWithPrefix(Name, MO.getSymbolName(), DL);
54  } else {
55    const GlobalValue *GV = MO.getGlobal();
56    TM.getNameWithPrefix(Name, GV, Mang);
57  }
58
59  Name += Suffix;
60  MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
61
62  // If the symbol reference is actually to a non_lazy_ptr, not to the symbol,
63  // then add the suffix.
64  if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG) {
65    MachineModuleInfoMachO &MachO = getMachOMMI(AP);
66
67    MachineModuleInfoImpl::StubValueTy &StubSym = MachO.getGVStubEntry(Sym);
68
69    if (!StubSym.getPointer()) {
70      assert(MO.isGlobal() && "Extern symbol not handled yet");
71      StubSym = MachineModuleInfoImpl::
72                   StubValueTy(AP.getSymbol(MO.getGlobal()),
73                               !MO.getGlobal()->hasInternalLinkage());
74    }
75    return Sym;
76  }
77
78  return Sym;
79}
80
81static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
82                              AsmPrinter &Printer, bool IsDarwin) {
83  MCContext &Ctx = Printer.OutContext;
84  MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
85
86  unsigned access = MO.getTargetFlags() & PPCII::MO_ACCESS_MASK;
87
88  switch (access) {
89    case PPCII::MO_TPREL_LO:
90      RefKind = MCSymbolRefExpr::VK_PPC_TPREL_LO;
91      break;
92    case PPCII::MO_TPREL_HA:
93      RefKind = MCSymbolRefExpr::VK_PPC_TPREL_HA;
94      break;
95    case PPCII::MO_DTPREL_LO:
96      RefKind = MCSymbolRefExpr::VK_PPC_DTPREL_LO;
97      break;
98    case PPCII::MO_TLSLD_LO:
99      RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO;
100      break;
101    case PPCII::MO_TOC_LO:
102      RefKind = MCSymbolRefExpr::VK_PPC_TOC_LO;
103      break;
104    case PPCII::MO_TLS:
105      RefKind = MCSymbolRefExpr::VK_PPC_TLS;
106      break;
107  }
108
109 if (MO.getTargetFlags() == PPCII::MO_PLT)
110    RefKind = MCSymbolRefExpr::VK_PLT;
111
112  const MachineFunction *MF = MO.getParent()->getParent()->getParent();
113  const Module *M = MF->getFunction().getParent();
114  const PPCSubtarget *Subtarget = &(MF->getSubtarget<PPCSubtarget>());
115  const TargetMachine &TM = Printer.TM;
116  const MCExpr *Expr = MCSymbolRefExpr::create(Symbol, RefKind, Ctx);
117  // If -msecure-plt -fPIC, add 32768 to symbol.
118  if (Subtarget->isSecurePlt() && TM.isPositionIndependent() &&
119      M->getPICLevel() == PICLevel::BigPIC &&
120      MO.getTargetFlags() == PPCII::MO_PLT)
121    Expr =
122        MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(32768, Ctx), Ctx);
123
124  if (!MO.isJTI() && MO.getOffset())
125    Expr = MCBinaryExpr::createAdd(Expr,
126                                   MCConstantExpr::create(MO.getOffset(), Ctx),
127                                   Ctx);
128
129  // Subtract off the PIC base if required.
130  if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG) {
131    const MachineFunction *MF = MO.getParent()->getParent()->getParent();
132
133    const MCExpr *PB = MCSymbolRefExpr::create(MF->getPICBaseSymbol(), Ctx);
134    Expr = MCBinaryExpr::createSub(Expr, PB, Ctx);
135  }
136
137  // Add ha16() / lo16() markers if required.
138  switch (access) {
139    case PPCII::MO_LO:
140      Expr = PPCMCExpr::createLo(Expr, IsDarwin, Ctx);
141      break;
142    case PPCII::MO_HA:
143      Expr = PPCMCExpr::createHa(Expr, IsDarwin, Ctx);
144      break;
145  }
146
147  return MCOperand::createExpr(Expr);
148}
149
150void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
151                                        AsmPrinter &AP, bool IsDarwin) {
152  OutMI.setOpcode(MI->getOpcode());
153
154  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
155    MCOperand MCOp;
156    if (LowerPPCMachineOperandToMCOperand(MI->getOperand(i), MCOp, AP,
157                                          IsDarwin))
158      OutMI.addOperand(MCOp);
159  }
160}
161
162bool llvm::LowerPPCMachineOperandToMCOperand(const MachineOperand &MO,
163                                             MCOperand &OutMO, AsmPrinter &AP,
164                                             bool IsDarwin) {
165  switch (MO.getType()) {
166  default:
167    llvm_unreachable("unknown operand type");
168  case MachineOperand::MO_Register:
169    assert(!MO.getSubReg() && "Subregs should be eliminated!");
170    assert(MO.getReg() > PPC::NoRegister &&
171           MO.getReg() < PPC::NUM_TARGET_REGS &&
172           "Invalid register for this target!");
173    OutMO = MCOperand::createReg(MO.getReg());
174    return true;
175  case MachineOperand::MO_Immediate:
176    OutMO = MCOperand::createImm(MO.getImm());
177    return true;
178  case MachineOperand::MO_MachineBasicBlock:
179    OutMO = MCOperand::createExpr(
180        MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), AP.OutContext));
181    return true;
182  case MachineOperand::MO_GlobalAddress:
183  case MachineOperand::MO_ExternalSymbol:
184    OutMO = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP, IsDarwin);
185    return true;
186  case MachineOperand::MO_JumpTableIndex:
187    OutMO = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP, IsDarwin);
188    return true;
189  case MachineOperand::MO_ConstantPoolIndex:
190    OutMO = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP, IsDarwin);
191    return true;
192  case MachineOperand::MO_BlockAddress:
193    OutMO = GetSymbolRef(MO, AP.GetBlockAddressSymbol(MO.getBlockAddress()), AP,
194                         IsDarwin);
195    return true;
196  case MachineOperand::MO_MCSymbol:
197    OutMO = GetSymbolRef(MO, MO.getMCSymbol(), AP, IsDarwin);
198    return true;
199  case MachineOperand::MO_RegisterMask:
200    return false;
201  }
202}
203