1 //===-- PPCAsmBackend.cpp - PPC Assembler Backend -------------------------===// 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 #include "MCTargetDesc/PPCMCTargetDesc.h" 11 #include "MCTargetDesc/PPCFixupKinds.h" 12 #include "llvm/MC/MCAsmBackend.h" 13 #include "llvm/MC/MCELFObjectWriter.h" 14 #include "llvm/MC/MCFixupKindInfo.h" 15 #include "llvm/MC/MCMachObjectWriter.h" 16 #include "llvm/MC/MCObjectWriter.h" 17 #include "llvm/MC/MCSectionMachO.h" 18 #include "llvm/MC/MCValue.h" 19 #include "llvm/Object/MachOFormat.h" 20 #include "llvm/Support/ELF.h" 21 #include "llvm/Support/ErrorHandling.h" 22 #include "llvm/Support/TargetRegistry.h" 23 using namespace llvm; 24 25 static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { 26 switch (Kind) { 27 default: 28 llvm_unreachable("Unknown fixup kind!"); 29 case FK_Data_1: 30 case FK_Data_2: 31 case FK_Data_4: 32 case FK_Data_8: 33 case PPC::fixup_ppc_toc: 34 case PPC::fixup_ppc_tlsreg: 35 return Value; 36 case PPC::fixup_ppc_lo14: 37 case PPC::fixup_ppc_toc16_ds: 38 return (Value & 0xffff) << 2; 39 case PPC::fixup_ppc_brcond14: 40 return Value & 0xfffc; 41 case PPC::fixup_ppc_br24: 42 return Value & 0x3fffffc; 43 #if 0 44 case PPC::fixup_ppc_hi16: 45 return (Value >> 16) & 0xffff; 46 #endif 47 case PPC::fixup_ppc_ha16: 48 return ((Value >> 16) + ((Value & 0x8000) ? 1 : 0)) & 0xffff; 49 case PPC::fixup_ppc_lo16: 50 case PPC::fixup_ppc_toc16: 51 return Value & 0xffff; 52 } 53 } 54 55 namespace { 56 class PPCMachObjectWriter : public MCMachObjectTargetWriter { 57 public: 58 PPCMachObjectWriter(bool Is64Bit, uint32_t CPUType, 59 uint32_t CPUSubtype) 60 : MCMachObjectTargetWriter(Is64Bit, CPUType, CPUSubtype) {} 61 62 void RecordRelocation(MachObjectWriter *Writer, 63 const MCAssembler &Asm, const MCAsmLayout &Layout, 64 const MCFragment *Fragment, const MCFixup &Fixup, 65 MCValue Target, uint64_t &FixedValue) { 66 llvm_unreachable("Relocation emission for MachO/PPC unimplemented!"); 67 } 68 }; 69 70 class PPCAsmBackend : public MCAsmBackend { 71 const Target &TheTarget; 72 public: 73 PPCAsmBackend(const Target &T) : MCAsmBackend(), TheTarget(T) {} 74 75 unsigned getNumFixupKinds() const { return PPC::NumTargetFixupKinds; } 76 77 const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const { 78 const static MCFixupKindInfo Infos[PPC::NumTargetFixupKinds] = { 79 // name offset bits flags 80 { "fixup_ppc_br24", 6, 24, MCFixupKindInfo::FKF_IsPCRel }, 81 { "fixup_ppc_brcond14", 16, 14, MCFixupKindInfo::FKF_IsPCRel }, 82 { "fixup_ppc_lo16", 16, 16, 0 }, 83 { "fixup_ppc_ha16", 16, 16, 0 }, 84 { "fixup_ppc_lo14", 16, 14, 0 }, 85 { "fixup_ppc_toc", 0, 64, 0 }, 86 { "fixup_ppc_toc16", 16, 16, 0 }, 87 { "fixup_ppc_toc16_ds", 16, 14, 0 }, 88 { "fixup_ppc_tlsreg", 0, 0, 0 } 89 }; 90 91 if (Kind < FirstTargetFixupKind) 92 return MCAsmBackend::getFixupKindInfo(Kind); 93 94 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && 95 "Invalid kind!"); 96 return Infos[Kind - FirstTargetFixupKind]; 97 } 98 99 void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, 100 uint64_t Value) const { 101 Value = adjustFixupValue(Fixup.getKind(), Value); 102 if (!Value) return; // Doesn't change encoding. 103 104 unsigned Offset = Fixup.getOffset(); 105 106 // For each byte of the fragment that the fixup touches, mask in the bits 107 // from the fixup value. The Value has been "split up" into the appropriate 108 // bitfields above. 109 for (unsigned i = 0; i != 4; ++i) 110 Data[Offset + i] |= uint8_t((Value >> ((4 - i - 1)*8)) & 0xff); 111 } 112 113 bool mayNeedRelaxation(const MCInst &Inst) const { 114 // FIXME. 115 return false; 116 } 117 118 bool fixupNeedsRelaxation(const MCFixup &Fixup, 119 uint64_t Value, 120 const MCInstFragment *DF, 121 const MCAsmLayout &Layout) const { 122 // FIXME. 123 llvm_unreachable("relaxInstruction() unimplemented"); 124 } 125 126 127 void relaxInstruction(const MCInst &Inst, MCInst &Res) const { 128 // FIXME. 129 llvm_unreachable("relaxInstruction() unimplemented"); 130 } 131 132 bool writeNopData(uint64_t Count, MCObjectWriter *OW) const { 133 // FIXME: Zero fill for now. That's not right, but at least will get the 134 // section size right. 135 for (uint64_t i = 0; i != Count; ++i) 136 OW->Write8(0); 137 return true; 138 } 139 140 unsigned getPointerSize() const { 141 StringRef Name = TheTarget.getName(); 142 if (Name == "ppc64") return 8; 143 assert(Name == "ppc32" && "Unknown target name!"); 144 return 4; 145 } 146 }; 147 } // end anonymous namespace 148 149 150 // FIXME: This should be in a separate file. 151 namespace { 152 class DarwinPPCAsmBackend : public PPCAsmBackend { 153 public: 154 DarwinPPCAsmBackend(const Target &T) : PPCAsmBackend(T) { } 155 156 MCObjectWriter *createObjectWriter(raw_ostream &OS) const { 157 bool is64 = getPointerSize() == 8; 158 return createMachObjectWriter(new PPCMachObjectWriter( 159 /*Is64Bit=*/is64, 160 (is64 ? object::mach::CTM_PowerPC64 : 161 object::mach::CTM_PowerPC), 162 object::mach::CSPPC_ALL), 163 OS, /*IsLittleEndian=*/false); 164 } 165 166 virtual bool doesSectionRequireSymbols(const MCSection &Section) const { 167 return false; 168 } 169 }; 170 171 class ELFPPCAsmBackend : public PPCAsmBackend { 172 uint8_t OSABI; 173 public: 174 ELFPPCAsmBackend(const Target &T, uint8_t OSABI) : 175 PPCAsmBackend(T), OSABI(OSABI) { } 176 177 178 MCObjectWriter *createObjectWriter(raw_ostream &OS) const { 179 bool is64 = getPointerSize() == 8; 180 return createPPCELFObjectWriter(OS, is64, OSABI); 181 } 182 183 virtual bool doesSectionRequireSymbols(const MCSection &Section) const { 184 return false; 185 } 186 }; 187 188 } // end anonymous namespace 189 190 191 192 193 MCAsmBackend *llvm::createPPCAsmBackend(const Target &T, StringRef TT, StringRef CPU) { 194 if (Triple(TT).isOSDarwin()) 195 return new DarwinPPCAsmBackend(T); 196 197 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS()); 198 return new ELFPPCAsmBackend(T, OSABI); 199 } 200