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/MCSectionMachO.h" 17 #include "llvm/MC/MCObjectWriter.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 return Value; 33 case PPC::fixup_ppc_brcond14: 34 return Value & 0x3ffc; 35 case PPC::fixup_ppc_br24: 36 return Value & 0x3fffffc; 37 #if 0 38 case PPC::fixup_ppc_hi16: 39 return (Value >> 16) & 0xffff; 40 #endif 41 case PPC::fixup_ppc_ha16: 42 return ((Value >> 16) + ((Value & 0x8000) ? 1 : 0)) & 0xffff; 43 case PPC::fixup_ppc_lo16: 44 return Value & 0xffff; 45 } 46 } 47 48 namespace { 49 class PPCMachObjectWriter : public MCMachObjectTargetWriter { 50 public: 51 PPCMachObjectWriter(bool Is64Bit, uint32_t CPUType, 52 uint32_t CPUSubtype) 53 : MCMachObjectTargetWriter(Is64Bit, CPUType, CPUSubtype) {} 54 55 void RecordRelocation(MachObjectWriter *Writer, 56 const MCAssembler &Asm, const MCAsmLayout &Layout, 57 const MCFragment *Fragment, const MCFixup &Fixup, 58 MCValue Target, uint64_t &FixedValue) {} 59 }; 60 61 class PPCAsmBackend : public MCAsmBackend { 62 const Target &TheTarget; 63 public: 64 PPCAsmBackend(const Target &T) : MCAsmBackend(), TheTarget(T) {} 65 66 unsigned getNumFixupKinds() const { return PPC::NumTargetFixupKinds; } 67 68 const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const { 69 const static MCFixupKindInfo Infos[PPC::NumTargetFixupKinds] = { 70 // name offset bits flags 71 { "fixup_ppc_br24", 6, 24, MCFixupKindInfo::FKF_IsPCRel }, 72 { "fixup_ppc_brcond14", 16, 14, MCFixupKindInfo::FKF_IsPCRel }, 73 { "fixup_ppc_lo16", 16, 16, 0 }, 74 { "fixup_ppc_ha16", 16, 16, 0 }, 75 { "fixup_ppc_lo14", 16, 14, 0 } 76 }; 77 78 if (Kind < FirstTargetFixupKind) 79 return MCAsmBackend::getFixupKindInfo(Kind); 80 81 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && 82 "Invalid kind!"); 83 return Infos[Kind - FirstTargetFixupKind]; 84 } 85 86 bool mayNeedRelaxation(const MCInst &Inst) const { 87 // FIXME. 88 return false; 89 } 90 91 bool fixupNeedsRelaxation(const MCFixup &Fixup, 92 uint64_t Value, 93 const MCInstFragment *DF, 94 const MCAsmLayout &Layout) const { 95 // FIXME. 96 llvm_unreachable("relaxInstruction() unimplemented"); 97 } 98 99 100 void relaxInstruction(const MCInst &Inst, MCInst &Res) const { 101 // FIXME. 102 llvm_unreachable("relaxInstruction() unimplemented"); 103 } 104 105 bool writeNopData(uint64_t Count, MCObjectWriter *OW) const { 106 // FIXME: Zero fill for now. That's not right, but at least will get the 107 // section size right. 108 for (uint64_t i = 0; i != Count; ++i) 109 OW->Write8(0); 110 return true; 111 } 112 113 unsigned getPointerSize() const { 114 StringRef Name = TheTarget.getName(); 115 if (Name == "ppc64") return 8; 116 assert(Name == "ppc32" && "Unknown target name!"); 117 return 4; 118 } 119 }; 120 } // end anonymous namespace 121 122 123 // FIXME: This should be in a separate file. 124 namespace { 125 class DarwinPPCAsmBackend : public PPCAsmBackend { 126 public: 127 DarwinPPCAsmBackend(const Target &T) : PPCAsmBackend(T) { } 128 129 void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, 130 uint64_t Value) const { 131 llvm_unreachable("UNIMP"); 132 } 133 134 MCObjectWriter *createObjectWriter(raw_ostream &OS) const { 135 bool is64 = getPointerSize() == 8; 136 return createMachObjectWriter(new PPCMachObjectWriter( 137 /*Is64Bit=*/is64, 138 (is64 ? object::mach::CTM_PowerPC64 : 139 object::mach::CTM_PowerPC), 140 object::mach::CSPPC_ALL), 141 OS, /*IsLittleEndian=*/false); 142 } 143 144 virtual bool doesSectionRequireSymbols(const MCSection &Section) const { 145 return false; 146 } 147 }; 148 149 class ELFPPCAsmBackend : public PPCAsmBackend { 150 uint8_t OSABI; 151 public: 152 ELFPPCAsmBackend(const Target &T, uint8_t OSABI) : 153 PPCAsmBackend(T), OSABI(OSABI) { } 154 155 void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, 156 uint64_t Value) const { 157 Value = adjustFixupValue(Fixup.getKind(), Value); 158 if (!Value) return; // Doesn't change encoding. 159 160 unsigned Offset = Fixup.getOffset(); 161 162 // For each byte of the fragment that the fixup touches, mask in the bits from 163 // the fixup value. The Value has been "split up" into the appropriate 164 // bitfields above. 165 for (unsigned i = 0; i != 4; ++i) 166 Data[Offset + i] |= uint8_t((Value >> ((4 - i - 1)*8)) & 0xff); 167 } 168 169 MCObjectWriter *createObjectWriter(raw_ostream &OS) const { 170 bool is64 = getPointerSize() == 8; 171 return createPPCELFObjectWriter(OS, is64, OSABI); 172 } 173 174 virtual bool doesSectionRequireSymbols(const MCSection &Section) const { 175 return false; 176 } 177 }; 178 179 } // end anonymous namespace 180 181 182 183 184 MCAsmBackend *llvm::createPPCAsmBackend(const Target &T, StringRef TT) { 185 if (Triple(TT).isOSDarwin()) 186 return new DarwinPPCAsmBackend(T); 187 188 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS()); 189 return new ELFPPCAsmBackend(T, OSABI); 190 } 191
