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 case PPC::fixup_ppc_nofixup: 36 return Value; 37 case PPC::fixup_ppc_lo14: 38 case PPC::fixup_ppc_toc16_ds: 39 return (Value & 0xffff) << 2; 40 case PPC::fixup_ppc_brcond14: 41 return Value & 0xfffc; 42 case PPC::fixup_ppc_br24: 43 return Value & 0x3fffffc; 44 #if 0 45 case PPC::fixup_ppc_hi16: 46 return (Value >> 16) & 0xffff; 47 #endif 48 case PPC::fixup_ppc_ha16: 49 return ((Value >> 16) + ((Value & 0x8000) ? 1 : 0)) & 0xffff; 50 case PPC::fixup_ppc_lo16: 51 case PPC::fixup_ppc_toc16: 52 return Value & 0xffff; 53 } 54 } 55 56 namespace { 57 class PPCMachObjectWriter : public MCMachObjectTargetWriter { 58 public: 59 PPCMachObjectWriter(bool Is64Bit, uint32_t CPUType, 60 uint32_t CPUSubtype) 61 : MCMachObjectTargetWriter(Is64Bit, CPUType, CPUSubtype) {} 62 63 void RecordRelocation(MachObjectWriter *Writer, 64 const MCAssembler &Asm, const MCAsmLayout &Layout, 65 const MCFragment *Fragment, const MCFixup &Fixup, 66 MCValue Target, uint64_t &FixedValue) { 67 llvm_unreachable("Relocation emission for MachO/PPC unimplemented!"); 68 } 69 }; 70 71 class PPCAsmBackend : public MCAsmBackend { 72 const Target &TheTarget; 73 public: 74 PPCAsmBackend(const Target &T) : MCAsmBackend(), TheTarget(T) {} 75 76 unsigned getNumFixupKinds() const { return PPC::NumTargetFixupKinds; } 77 78 const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const { 79 const static MCFixupKindInfo Infos[PPC::NumTargetFixupKinds] = { 80 // name offset bits flags 81 { "fixup_ppc_br24", 6, 24, MCFixupKindInfo::FKF_IsPCRel }, 82 { "fixup_ppc_brcond14", 16, 14, MCFixupKindInfo::FKF_IsPCRel }, 83 { "fixup_ppc_lo16", 16, 16, 0 }, 84 { "fixup_ppc_ha16", 16, 16, 0 }, 85 { "fixup_ppc_lo14", 16, 14, 0 }, 86 { "fixup_ppc_toc", 0, 64, 0 }, 87 { "fixup_ppc_toc16", 16, 16, 0 }, 88 { "fixup_ppc_toc16_ds", 16, 14, 0 }, 89 { "fixup_ppc_tlsreg", 0, 0, 0 }, 90 { "fixup_ppc_nofixup", 0, 0, 0 } 91 }; 92 93 if (Kind < FirstTargetFixupKind) 94 return MCAsmBackend::getFixupKindInfo(Kind); 95 96 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && 97 "Invalid kind!"); 98 return Infos[Kind - FirstTargetFixupKind]; 99 } 100 101 void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, 102 uint64_t Value) const { 103 Value = adjustFixupValue(Fixup.getKind(), Value); 104 if (!Value) return; // Doesn't change encoding. 105 106 unsigned Offset = Fixup.getOffset(); 107 108 // For each byte of the fragment that the fixup touches, mask in the bits 109 // from the fixup value. The Value has been "split up" into the appropriate 110 // bitfields above. 111 for (unsigned i = 0; i != 4; ++i) 112 Data[Offset + i] |= uint8_t((Value >> ((4 - i - 1)*8)) & 0xff); 113 } 114 115 bool mayNeedRelaxation(const MCInst &Inst) const { 116 // FIXME. 117 return false; 118 } 119 120 bool fixupNeedsRelaxation(const MCFixup &Fixup, 121 uint64_t Value, 122 const MCRelaxableFragment *DF, 123 const MCAsmLayout &Layout) const { 124 // FIXME. 125 llvm_unreachable("relaxInstruction() unimplemented"); 126 } 127 128 129 void relaxInstruction(const MCInst &Inst, MCInst &Res) const { 130 // FIXME. 131 llvm_unreachable("relaxInstruction() unimplemented"); 132 } 133 134 bool writeNopData(uint64_t Count, MCObjectWriter *OW) const { 135 // FIXME: Zero fill for now. That's not right, but at least will get the 136 // section size right. 137 for (uint64_t i = 0; i != Count; ++i) 138 OW->Write8(0); 139 return true; 140 } 141 142 unsigned getPointerSize() const { 143 StringRef Name = TheTarget.getName(); 144 if (Name == "ppc64") return 8; 145 assert(Name == "ppc32" && "Unknown target name!"); 146 return 4; 147 } 148 }; 149 } // end anonymous namespace 150 151 152 // FIXME: This should be in a separate file. 153 namespace { 154 class DarwinPPCAsmBackend : public PPCAsmBackend { 155 public: 156 DarwinPPCAsmBackend(const Target &T) : PPCAsmBackend(T) { } 157 158 MCObjectWriter *createObjectWriter(raw_ostream &OS) const { 159 bool is64 = getPointerSize() == 8; 160 return createMachObjectWriter(new PPCMachObjectWriter( 161 /*Is64Bit=*/is64, 162 (is64 ? object::mach::CTM_PowerPC64 : 163 object::mach::CTM_PowerPC), 164 object::mach::CSPPC_ALL), 165 OS, /*IsLittleEndian=*/false); 166 } 167 168 virtual bool doesSectionRequireSymbols(const MCSection &Section) const { 169 return false; 170 } 171 }; 172 173 class ELFPPCAsmBackend : public PPCAsmBackend { 174 uint8_t OSABI; 175 public: 176 ELFPPCAsmBackend(const Target &T, uint8_t OSABI) : 177 PPCAsmBackend(T), OSABI(OSABI) { } 178 179 180 MCObjectWriter *createObjectWriter(raw_ostream &OS) const { 181 bool is64 = getPointerSize() == 8; 182 return createPPCELFObjectWriter(OS, is64, OSABI); 183 } 184 185 virtual bool doesSectionRequireSymbols(const MCSection &Section) const { 186 return false; 187 } 188 }; 189 190 } // end anonymous namespace 191 192 193 194 195 MCAsmBackend *llvm::createPPCAsmBackend(const Target &T, StringRef TT, StringRef CPU) { 196 if (Triple(TT).isOSDarwin()) 197 return new DarwinPPCAsmBackend(T); 198 199 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS()); 200 return new ELFPPCAsmBackend(T, OSABI); 201 } 202
