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" 30 using namespace llvm; 31 32 static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO, 33 AsmPrinter &AP) { 34 if (MO.isGlobal()) { 35 // Get the symbol from the global, accounting for XCOFF-specific 36 // intricacies (see TargetLoweringObjectFileXCOFF::getTargetSymbol). 37 const GlobalValue *GV = MO.getGlobal(); 38 return AP.getSymbol(GV); 39 } 40 41 assert(MO.isSymbol() && "Isn't a symbol reference"); 42 43 SmallString<128> Name; 44 const DataLayout &DL = AP.getDataLayout(); 45 Mangler::getNameWithPrefix(Name, MO.getSymbolName(), DL); 46 47 MCContext &Ctx = AP.OutContext; 48 MCSymbol *Sym = Ctx.getOrCreateSymbol(Name); 49 return Sym; 50 } 51 52 static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol, 53 AsmPrinter &Printer) { 54 MCContext &Ctx = Printer.OutContext; 55 MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None; 56 57 unsigned access = MO.getTargetFlags(); 58 59 switch (access) { 60 case PPCII::MO_TPREL_LO: 61 RefKind = MCSymbolRefExpr::VK_PPC_TPREL_LO; 62 break; 63 case PPCII::MO_TPREL_HA: 64 RefKind = MCSymbolRefExpr::VK_PPC_TPREL_HA; 65 break; 66 case PPCII::MO_DTPREL_LO: 67 RefKind = MCSymbolRefExpr::VK_PPC_DTPREL_LO; 68 break; 69 case PPCII::MO_TLSLD_LO: 70 RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO; 71 break; 72 case PPCII::MO_TOC_LO: 73 RefKind = MCSymbolRefExpr::VK_PPC_TOC_LO; 74 break; 75 case PPCII::MO_TLS: 76 RefKind = MCSymbolRefExpr::VK_PPC_TLS; 77 break; 78 case PPCII::MO_TLS_PCREL_FLAG: 79 RefKind = MCSymbolRefExpr::VK_PPC_TLS_PCREL; 80 break; 81 } 82 83 const TargetMachine &TM = Printer.TM; 84 85 if (MO.getTargetFlags() == PPCII::MO_PLT) 86 RefKind = MCSymbolRefExpr::VK_PLT; 87 else if (MO.getTargetFlags() == PPCII::MO_PCREL_FLAG) 88 RefKind = MCSymbolRefExpr::VK_PCREL; 89 else if (MO.getTargetFlags() == PPCII::MO_GOT_PCREL_FLAG) 90 RefKind = MCSymbolRefExpr::VK_PPC_GOT_PCREL; 91 else if (MO.getTargetFlags() == PPCII::MO_TPREL_PCREL_FLAG) 92 RefKind = MCSymbolRefExpr::VK_TPREL; 93 else if (MO.getTargetFlags() == PPCII::MO_GOT_TLSGD_PCREL_FLAG) 94 RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSGD_PCREL; 95 else if (MO.getTargetFlags() == PPCII::MO_GOT_TLSLD_PCREL_FLAG) 96 RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_PCREL; 97 else if (MO.getTargetFlags() == PPCII::MO_GOT_TPREL_PCREL_FLAG) 98 RefKind = MCSymbolRefExpr::VK_PPC_GOT_TPREL_PCREL; 99 else if (MO.getTargetFlags() == PPCII::MO_TPREL_FLAG || 100 MO.getTargetFlags() == PPCII::MO_TLSLD_FLAG) { 101 assert(MO.isGlobal() && "Only expecting a global MachineOperand here!"); 102 TLSModel::Model Model = TM.getTLSModel(MO.getGlobal()); 103 // For the local-[exec|dynamic] TLS model, we may generate the offset from 104 // the TLS base as an immediate operand (instead of using a TOC entry). Set 105 // the relocation type in case the result is used for purposes other than a 106 // TOC reference. In TOC reference cases, this result is discarded. 107 if (Model == TLSModel::LocalExec) 108 RefKind = MCSymbolRefExpr::VK_PPC_AIX_TLSLE; 109 else if (Model == TLSModel::LocalDynamic) 110 RefKind = MCSymbolRefExpr::VK_PPC_AIX_TLSLD; 111 } 112 113 const MachineInstr *MI = MO.getParent(); 114 const MachineFunction *MF = MI->getMF(); 115 const Module *M = MF->getFunction().getParent(); 116 const PPCSubtarget *Subtarget = &(MF->getSubtarget<PPCSubtarget>()); 117 118 unsigned MIOpcode = MI->getOpcode(); 119 assert((Subtarget->isUsingPCRelativeCalls() || MIOpcode != PPC::BL8_NOTOC) && 120 "BL8_NOTOC is only valid when using PC Relative Calls."); 121 if (Subtarget->isUsingPCRelativeCalls()) { 122 if (MIOpcode == PPC::TAILB || MIOpcode == PPC::TAILB8 || 123 MIOpcode == PPC::TCRETURNdi || MIOpcode == PPC::TCRETURNdi8 || 124 MIOpcode == PPC::BL8_NOTOC || MIOpcode == PPC::BL8_NOTOC_RM) { 125 RefKind = MCSymbolRefExpr::VK_PPC_NOTOC; 126 } 127 if (MO.getTargetFlags() == PPCII::MO_PCREL_OPT_FLAG) 128 RefKind = MCSymbolRefExpr::VK_PPC_PCREL_OPT; 129 } 130 131 const MCExpr *Expr = MCSymbolRefExpr::create(Symbol, RefKind, Ctx); 132 // If -msecure-plt -fPIC, add 32768 to symbol. 133 if (Subtarget->isSecurePlt() && TM.isPositionIndependent() && 134 M->getPICLevel() == PICLevel::BigPIC && 135 MO.getTargetFlags() == PPCII::MO_PLT) 136 Expr = 137 MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(32768, Ctx), Ctx); 138 139 if (!MO.isJTI() && MO.getOffset()) 140 Expr = MCBinaryExpr::createAdd(Expr, 141 MCConstantExpr::create(MO.getOffset(), Ctx), 142 Ctx); 143 144 // Subtract off the PIC base if required. 145 if (MO.getTargetFlags() == PPCII::MO_PIC_FLAG || 146 MO.getTargetFlags() == PPCII::MO_PIC_HA_FLAG || 147 MO.getTargetFlags() == PPCII::MO_PIC_LO_FLAG) { 148 const MachineFunction *MF = MO.getParent()->getParent()->getParent(); 149 150 const MCExpr *PB = MCSymbolRefExpr::create(MF->getPICBaseSymbol(), Ctx); 151 Expr = MCBinaryExpr::createSub(Expr, PB, Ctx); 152 } 153 154 // Add ha16() / lo16() markers if required. 155 switch (access) { 156 case PPCII::MO_LO: 157 case PPCII::MO_PIC_LO_FLAG: 158 Expr = PPCMCExpr::createLo(Expr, Ctx); 159 break; 160 case PPCII::MO_HA: 161 case PPCII::MO_PIC_HA_FLAG: 162 Expr = PPCMCExpr::createHa(Expr, Ctx); 163 break; 164 } 165 166 return MCOperand::createExpr(Expr); 167 } 168 169 void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI, 170 AsmPrinter &AP) { 171 OutMI.setOpcode(MI->getOpcode()); 172 173 for (const MachineOperand &MO : MI->operands()) { 174 MCOperand MCOp; 175 if (LowerPPCMachineOperandToMCOperand(MO, MCOp, AP)) 176 OutMI.addOperand(MCOp); 177 } 178 } 179 180 bool llvm::LowerPPCMachineOperandToMCOperand(const MachineOperand &MO, 181 MCOperand &OutMO, AsmPrinter &AP) { 182 switch (MO.getType()) { 183 default: 184 llvm_unreachable("unknown operand type"); 185 case MachineOperand::MO_Register: 186 assert(!MO.getSubReg() && "Subregs should be eliminated!"); 187 assert(MO.getReg() > PPC::NoRegister && 188 MO.getReg() < PPC::NUM_TARGET_REGS && 189 "Invalid register for this target!"); 190 // Ignore all implicit register operands. 191 if (MO.isImplicit()) 192 return false; 193 OutMO = MCOperand::createReg(MO.getReg()); 194 return true; 195 case MachineOperand::MO_Immediate: 196 OutMO = MCOperand::createImm(MO.getImm()); 197 return true; 198 case MachineOperand::MO_MachineBasicBlock: 199 OutMO = MCOperand::createExpr( 200 MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), AP.OutContext)); 201 return true; 202 case MachineOperand::MO_GlobalAddress: 203 case MachineOperand::MO_ExternalSymbol: 204 OutMO = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP); 205 return true; 206 case MachineOperand::MO_JumpTableIndex: 207 OutMO = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP); 208 return true; 209 case MachineOperand::MO_ConstantPoolIndex: 210 OutMO = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP); 211 return true; 212 case MachineOperand::MO_BlockAddress: 213 OutMO = 214 GetSymbolRef(MO, AP.GetBlockAddressSymbol(MO.getBlockAddress()), AP); 215 return true; 216 case MachineOperand::MO_MCSymbol: 217 OutMO = GetSymbolRef(MO, MO.getMCSymbol(), AP); 218 return true; 219 case MachineOperand::MO_RegisterMask: 220 return false; 221 } 222 } 223