llvm/lib/Target/PowerPC/PPCMCInstLower.cpp

   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   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
  53 static 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       bool IsPCRel = (MO.getTargetFlags() & ~access) == PPCII::MO_PCREL_FLAG;
  78       RefKind = IsPCRel ? MCSymbolRefExpr::VK_PPC_TLS_PCREL
  79                         : MCSymbolRefExpr::VK_PPC_TLS;
  80       break;
  81   }
  82
  83   if (MO.getTargetFlags() == PPCII::MO_PLT)
  84     RefKind = MCSymbolRefExpr::VK_PLT;
  85   else if (MO.getTargetFlags() == PPCII::MO_PCREL_FLAG)
  86     RefKind = MCSymbolRefExpr::VK_PCREL;
  87   else if (MO.getTargetFlags() == (PPCII::MO_PCREL_FLAG | PPCII::MO_GOT_FLAG))
  88     RefKind = MCSymbolRefExpr::VK_PPC_GOT_PCREL;
  89   else if (MO.getTargetFlags() == (PPCII::MO_PCREL_FLAG | PPCII::MO_TPREL_FLAG))
  90     RefKind = MCSymbolRefExpr::VK_TPREL;
  91   else if (MO.getTargetFlags() == PPCII::MO_GOT_TLSGD_PCREL_FLAG)
  92     RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSGD_PCREL;
  93   else if (MO.getTargetFlags() == PPCII::MO_GOT_TLSLD_PCREL_FLAG)
  94     RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_PCREL;
  95   else if (MO.getTargetFlags() == PPCII::MO_GOT_TPREL_PCREL_FLAG)
  96     RefKind = MCSymbolRefExpr::VK_PPC_GOT_TPREL_PCREL;
  97
  98   const MachineInstr *MI = MO.getParent();
  99   const MachineFunction *MF = MI->getMF();
 100   const Module *M = MF->getFunction().getParent();
 101   const PPCSubtarget *Subtarget = &(MF->getSubtarget<PPCSubtarget>());
 102   const TargetMachine &TM = Printer.TM;
 103
 104   unsigned MIOpcode = MI->getOpcode();
 105   assert((Subtarget->isUsingPCRelativeCalls() || MIOpcode != PPC::BL8_NOTOC) &&
 106          "BL8_NOTOC is only valid when using PC Relative Calls.");
 107   if (Subtarget->isUsingPCRelativeCalls()) {
 108     if (MIOpcode == PPC::TAILB || MIOpcode == PPC::TAILB8 ||
 109         MIOpcode == PPC::TCRETURNdi || MIOpcode == PPC::TCRETURNdi8 ||
 110         MIOpcode == PPC::BL8_NOTOC) {
 111       RefKind = MCSymbolRefExpr::VK_PPC_NOTOC;
 112     }
 113     if (MO.getTargetFlags() == PPCII::MO_PCREL_OPT_FLAG)
 114       RefKind = MCSymbolRefExpr::VK_PPC_PCREL_OPT;
 115   }
 116
 117   const MCExpr *Expr = MCSymbolRefExpr::create(Symbol, RefKind, Ctx);
 118   // If -msecure-plt -fPIC, add 32768 to symbol.
 119   if (Subtarget->isSecurePlt() && TM.isPositionIndependent() &&
 120       M->getPICLevel() == PICLevel::BigPIC &&
 121       MO.getTargetFlags() == PPCII::MO_PLT)
 122     Expr =
 123         MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(32768, Ctx), Ctx);
 124
 125   if (!MO.isJTI() && MO.getOffset())
 126     Expr = MCBinaryExpr::createAdd(Expr,
 127                                    MCConstantExpr::create(MO.getOffset(), Ctx),
 128                                    Ctx);
 129
 130   // Subtract off the PIC base if required.
 131   if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG) {
 132     const MachineFunction *MF = MO.getParent()->getParent()->getParent();
 133
 134     const MCExpr *PB = MCSymbolRefExpr::create(MF->getPICBaseSymbol(), Ctx);
 135     Expr = MCBinaryExpr::createSub(Expr, PB, Ctx);
 136   }
 137
 138   // Add ha16() / lo16() markers if required.
 139   switch (access) {
 140     case PPCII::MO_LO:
 141       Expr = PPCMCExpr::createLo(Expr, Ctx);
 142       break;
 143     case PPCII::MO_HA:
 144       Expr = PPCMCExpr::createHa(Expr, Ctx);
 145       break;
 146   }
 147
 148   return MCOperand::createExpr(Expr);
 149 }
 150
 151 void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
 152                                         AsmPrinter &AP) {
 153   OutMI.setOpcode(MI->getOpcode());
 154
 155   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
 156     MCOperand MCOp;
 157     if (LowerPPCMachineOperandToMCOperand(MI->getOperand(i), MCOp, AP))
 158       OutMI.addOperand(MCOp);
 159   }
 160 }
 161
 162 bool llvm::LowerPPCMachineOperandToMCOperand(const MachineOperand &MO,
 163                                              MCOperand &OutMO, AsmPrinter &AP) {
 164   switch (MO.getType()) {
 165   default:
 166     llvm_unreachable("unknown operand type");
 167   case MachineOperand::MO_Register:
 168     assert(!MO.getSubReg() && "Subregs should be eliminated!");
 169     assert(MO.getReg() > PPC::NoRegister &&
 170            MO.getReg() < PPC::NUM_TARGET_REGS &&
 171            "Invalid register for this target!");
 172     // Ignore all implicit register operands.
 173     if (MO.isImplicit())
 174       return false;
 175     OutMO = MCOperand::createReg(MO.getReg());
 176     return true;
 177   case MachineOperand::MO_Immediate:
 178     OutMO = MCOperand::createImm(MO.getImm());
 179     return true;
 180   case MachineOperand::MO_MachineBasicBlock:
 181     OutMO = MCOperand::createExpr(
 182         MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), AP.OutContext));
 183     return true;
 184   case MachineOperand::MO_GlobalAddress:
 185   case MachineOperand::MO_ExternalSymbol:
 186     OutMO = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP);
 187     return true;
 188   case MachineOperand::MO_JumpTableIndex:
 189     OutMO = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP);
 190     return true;
 191   case MachineOperand::MO_ConstantPoolIndex:
 192     OutMO = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP);
 193     return true;
 194   case MachineOperand::MO_BlockAddress:
 195     OutMO =
 196         GetSymbolRef(MO, AP.GetBlockAddressSymbol(MO.getBlockAddress()), AP);
 197     return true;
 198   case MachineOperand::MO_MCSymbol:
 199     OutMO = GetSymbolRef(MO, MO.getMCSymbol(), AP);
 200     return true;
 201   case MachineOperand::MO_RegisterMask:
 202     return false;
 203   }
 204 }