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/Support/ELF.h" 20 #include "llvm/Support/ErrorHandling.h" 21 #include "llvm/Support/MachO.h" 22 #include "llvm/Support/TargetRegistry.h" 23 using namespace llvm; 24 25 static uint64_t 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_nofixup: 34 return Value; 35 case PPC::fixup_ppc_brcond14: 36 case PPC::fixup_ppc_brcond14abs: 37 return Value & 0xfffc; 38 case PPC::fixup_ppc_br24: 39 case PPC::fixup_ppc_br24abs: 40 return Value & 0x3fffffc; 41 case PPC::fixup_ppc_half16: 42 return Value & 0xffff; 43 case PPC::fixup_ppc_half16ds: 44 return Value & 0xfffc; 45 } 46 } 47 48 static unsigned getFixupKindNumBytes(unsigned Kind) { 49 switch (Kind) { 50 default: 51 llvm_unreachable("Unknown fixup kind!"); 52 case FK_Data_1: 53 return 1; 54 case FK_Data_2: 55 case PPC::fixup_ppc_half16: 56 case PPC::fixup_ppc_half16ds: 57 return 2; 58 case FK_Data_4: 59 case PPC::fixup_ppc_brcond14: 60 case PPC::fixup_ppc_brcond14abs: 61 case PPC::fixup_ppc_br24: 62 case PPC::fixup_ppc_br24abs: 63 return 4; 64 case FK_Data_8: 65 return 8; 66 case PPC::fixup_ppc_nofixup: 67 return 0; 68 } 69 } 70 71 namespace { 72 73 class PPCAsmBackend : public MCAsmBackend { 74 const Target &TheTarget; 75 public: 76 PPCAsmBackend(const Target &T) : MCAsmBackend(), TheTarget(T) {} 77 78 unsigned getNumFixupKinds() const { return PPC::NumTargetFixupKinds; } 79 80 const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const { 81 const static MCFixupKindInfo Infos[PPC::NumTargetFixupKinds] = { 82 // name offset bits flags 83 { "fixup_ppc_br24", 6, 24, MCFixupKindInfo::FKF_IsPCRel }, 84 { "fixup_ppc_brcond14", 16, 14, MCFixupKindInfo::FKF_IsPCRel }, 85 { "fixup_ppc_br24abs", 6, 24, 0 }, 86 { "fixup_ppc_brcond14abs", 16, 14, 0 }, 87 { "fixup_ppc_half16", 0, 16, 0 }, 88 { "fixup_ppc_half16ds", 0, 14, 0 }, 89 { "fixup_ppc_nofixup", 0, 0, 0 } 90 }; 91 92 if (Kind < FirstTargetFixupKind) 93 return MCAsmBackend::getFixupKindInfo(Kind); 94 95 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && 96 "Invalid kind!"); 97 return Infos[Kind - FirstTargetFixupKind]; 98 } 99 100 void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, 101 uint64_t Value) const { 102 Value = adjustFixupValue(Fixup.getKind(), Value); 103 if (!Value) return; // Doesn't change encoding. 104 105 unsigned Offset = Fixup.getOffset(); 106 unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind()); 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 != NumBytes; ++i) 112 Data[Offset + i] |= uint8_t((Value >> ((NumBytes - 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 uint64_t NumNops = Count / 4; 136 for (uint64_t i = 0; i != NumNops; ++i) 137 OW->Write32(0x60000000); 138 139 switch (Count % 4) { 140 default: break; // No leftover bytes to write 141 case 1: OW->Write8(0); break; 142 case 2: OW->Write16(0); break; 143 case 3: OW->Write16(0); OW->Write8(0); break; 144 } 145 146 return true; 147 } 148 149 unsigned getPointerSize() const { 150 StringRef Name = TheTarget.getName(); 151 if (Name == "ppc64" || Name == "ppc64le") return 8; 152 assert(Name == "ppc32" && "Unknown target name!"); 153 return 4; 154 } 155 }; 156 } // end anonymous namespace 157 158 159 // FIXME: This should be in a separate file. 160 namespace { 161 class DarwinPPCAsmBackend : public PPCAsmBackend { 162 public: 163 DarwinPPCAsmBackend(const Target &T) : PPCAsmBackend(T) { } 164 165 MCObjectWriter *createObjectWriter(raw_ostream &OS) const { 166 bool is64 = getPointerSize() == 8; 167 return createPPCMachObjectWriter( 168 OS, 169 /*Is64Bit=*/is64, 170 (is64 ? MachO::CPU_TYPE_POWERPC64 : MachO::CPU_TYPE_POWERPC), 171 MachO::CPU_SUBTYPE_POWERPC_ALL); 172 } 173 174 virtual bool doesSectionRequireSymbols(const MCSection &Section) const { 175 return false; 176 } 177 }; 178 179 class ELFPPCAsmBackend : public PPCAsmBackend { 180 uint8_t OSABI; 181 public: 182 ELFPPCAsmBackend(const Target &T, uint8_t OSABI) : 183 PPCAsmBackend(T), OSABI(OSABI) { } 184 185 186 MCObjectWriter *createObjectWriter(raw_ostream &OS) const { 187 bool is64 = getPointerSize() == 8; 188 return createPPCELFObjectWriter(OS, is64, OSABI); 189 } 190 191 virtual bool doesSectionRequireSymbols(const MCSection &Section) const { 192 return false; 193 } 194 }; 195 196 } // end anonymous namespace 197 198 MCAsmBackend *llvm::createPPCAsmBackend(const Target &T, 199 const MCRegisterInfo &MRI, 200 StringRef TT, StringRef CPU) { 201 if (Triple(TT).isOSDarwin()) 202 return new DarwinPPCAsmBackend(T); 203 204 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS()); 205 return new ELFPPCAsmBackend(T, OSABI); 206 } 207