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 MCSymbol *GetSymbolFromOperand(const MachineOperand &MO,
33                                      AsmPrinter &AP) {
34  const TargetMachine &TM = AP.TM;
35  Mangler &Mang = TM.getObjFileLowering()->getMangler();
36  const DataLayout &DL = AP.getDataLayout();
37  MCContext &Ctx = AP.OutContext;
38
39  SmallString<128> Name;
40  if (!MO.isGlobal()) {
41    assert(MO.isSymbol() && "Isn't a symbol reference");
42    Mangler::getNameWithPrefix(Name, MO.getSymbolName(), DL);
43  } else {
44    const GlobalValue *GV = MO.getGlobal();
45    TM.getNameWithPrefix(Name, GV, Mang);
46  }
47
48  MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
49
50  return Sym;
51}
52
53static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
54                              AsmPrinter &Printer) {
55  MCContext &Ctx = Printer.OutContext;
56  MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
57
58  unsigned access = MO.getTargetFlags() & PPCII::MO_ACCESS_MASK;
59
60  switch (access) {
61    case PPCII::MO_TPREL_LO:
62      RefKind = MCSymbolRefExpr::VK_PPC_TPREL_LO;
63      break;
64    case PPCII::MO_TPREL_HA:
65      RefKind = MCSymbolRefExpr::VK_PPC_TPREL_HA;
66      break;
67    case PPCII::MO_DTPREL_LO:
68      RefKind = MCSymbolRefExpr::VK_PPC_DTPREL_LO;
69      break;
70    case PPCII::MO_TLSLD_LO:
71      RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO;
72      break;
73    case PPCII::MO_TOC_LO:
74      RefKind = MCSymbolRefExpr::VK_PPC_TOC_LO;
75      break;
76    case PPCII::MO_TLS:
77      RefKind = MCSymbolRefExpr::VK_PPC_TLS;
78      break;
79  }
80
81  if (MO.getTargetFlags() == PPCII::MO_PLT)
82    RefKind = MCSymbolRefExpr::VK_PLT;
83  else if (MO.getTargetFlags() == PPCII::MO_PCREL_FLAG)
84    RefKind = MCSymbolRefExpr::VK_PCREL;
85  else if (MO.getTargetFlags() == (PPCII::MO_PCREL_FLAG | PPCII::MO_GOT_FLAG))
86    RefKind = MCSymbolRefExpr::VK_PPC_GOT_PCREL;
87
88  const MachineInstr *MI = MO.getParent();
89  const MachineFunction *MF = MI->getMF();
90  const Module *M = MF->getFunction().getParent();
91  const PPCSubtarget *Subtarget = &(MF->getSubtarget<PPCSubtarget>());
92  const TargetMachine &TM = Printer.TM;
93
94  unsigned MIOpcode = MI->getOpcode();
95  assert((Subtarget->isUsingPCRelativeCalls() || MIOpcode != PPC::BL8_NOTOC) &&
96         "BL8_NOTOC is only valid when using PC Relative Calls.");
97  if (Subtarget->isUsingPCRelativeCalls()) {
98    if (MIOpcode == PPC::TAILB || MIOpcode == PPC::TAILB8 ||
99        MIOpcode == PPC::TCRETURNdi || MIOpcode == PPC::TCRETURNdi8 ||
100        MIOpcode == PPC::BL8_NOTOC) {
101      RefKind = MCSymbolRefExpr::VK_PPC_NOTOC;
102    }
103  }
104
105  const MCExpr *Expr = MCSymbolRefExpr::create(Symbol, RefKind, Ctx);
106  // If -msecure-plt -fPIC, add 32768 to symbol.
107  if (Subtarget->isSecurePlt() && TM.isPositionIndependent() &&
108      M->getPICLevel() == PICLevel::BigPIC &&
109      MO.getTargetFlags() == PPCII::MO_PLT)
110    Expr =
111        MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(32768, Ctx), Ctx);
112
113  if (!MO.isJTI() && MO.getOffset())
114    Expr = MCBinaryExpr::createAdd(Expr,
115                                   MCConstantExpr::create(MO.getOffset(), Ctx),
116                                   Ctx);
117
118  // Subtract off the PIC base if required.
119  if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG) {
120    const MachineFunction *MF = MO.getParent()->getParent()->getParent();
121
122    const MCExpr *PB = MCSymbolRefExpr::create(MF->getPICBaseSymbol(), Ctx);
123    Expr = MCBinaryExpr::createSub(Expr, PB, Ctx);
124  }
125
126  // Add ha16() / lo16() markers if required.
127  switch (access) {
128    case PPCII::MO_LO:
129      Expr = PPCMCExpr::createLo(Expr, Ctx);
130      break;
131    case PPCII::MO_HA:
132      Expr = PPCMCExpr::createHa(Expr, Ctx);
133      break;
134  }
135
136  return MCOperand::createExpr(Expr);
137}
138
139void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
140                                        AsmPrinter &AP) {
141  OutMI.setOpcode(MI->getOpcode());
142
143  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
144    MCOperand MCOp;
145    if (LowerPPCMachineOperandToMCOperand(MI->getOperand(i), MCOp, AP))
146      OutMI.addOperand(MCOp);
147  }
148}
149
150bool llvm::LowerPPCMachineOperandToMCOperand(const MachineOperand &MO,
151                                             MCOperand &OutMO, AsmPrinter &AP) {
152  switch (MO.getType()) {
153  default:
154    llvm_unreachable("unknown operand type");
155  case MachineOperand::MO_Register:
156    assert(!MO.getSubReg() && "Subregs should be eliminated!");
157    assert(MO.getReg() > PPC::NoRegister &&
158           MO.getReg() < PPC::NUM_TARGET_REGS &&
159           "Invalid register for this target!");
160    // Ignore all implicit register operands.
161    if (MO.isImplicit())
162      return false;
163    OutMO = MCOperand::createReg(MO.getReg());
164    return true;
165  case MachineOperand::MO_Immediate:
166    OutMO = MCOperand::createImm(MO.getImm());
167    return true;
168  case MachineOperand::MO_MachineBasicBlock:
169    OutMO = MCOperand::createExpr(
170        MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), AP.OutContext));
171    return true;
172  case MachineOperand::MO_GlobalAddress:
173  case MachineOperand::MO_ExternalSymbol:
174    OutMO = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP);
175    return true;
176  case MachineOperand::MO_JumpTableIndex:
177    OutMO = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP);
178    return true;
179  case MachineOperand::MO_ConstantPoolIndex:
180    OutMO = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP);
181    return true;
182  case MachineOperand::MO_BlockAddress:
183    OutMO =
184        GetSymbolRef(MO, AP.GetBlockAddressSymbol(MO.getBlockAddress()), AP);
185    return true;
186  case MachineOperand::MO_MCSymbol:
187    OutMO = GetSymbolRef(MO, MO.getMCSymbol(), AP);
188    return true;
189  case MachineOperand::MO_RegisterMask:
190    return false;
191  }
192}
193