1 //===-- SystemZMCAsmBackend.cpp - SystemZ 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/SystemZMCTargetDesc.h" 11 #include "MCTargetDesc/SystemZMCFixups.h" 12 #include "llvm/MC/MCAsmBackend.h" 13 #include "llvm/MC/MCELFObjectWriter.h" 14 #include "llvm/MC/MCFixupKindInfo.h" 15 #include "llvm/MC/MCInst.h" 16 #include "llvm/MC/MCObjectWriter.h" 17 18 using namespace llvm; 19 20 // Value is a fully-resolved relocation value: Symbol + Addend [- Pivot]. 21 // Return the bits that should be installed in a relocation field for 22 // fixup kind Kind. 23 static uint64_t extractBitsForFixup(MCFixupKind Kind, uint64_t Value) { 24 if (Kind < FirstTargetFixupKind) 25 return Value; 26 27 switch (unsigned(Kind)) { 28 case SystemZ::FK_390_PC16DBL: 29 case SystemZ::FK_390_PC32DBL: 30 case SystemZ::FK_390_PLT16DBL: 31 case SystemZ::FK_390_PLT32DBL: 32 return (int64_t)Value / 2; 33 } 34 35 llvm_unreachable("Unknown fixup kind!"); 36 } 37 38 namespace { 39 class SystemZMCAsmBackend : public MCAsmBackend { 40 uint8_t OSABI; 41 public: 42 SystemZMCAsmBackend(uint8_t osABI) 43 : OSABI(osABI) {} 44 45 // Override MCAsmBackend 46 unsigned getNumFixupKinds() const override { 47 return SystemZ::NumTargetFixupKinds; 48 } 49 const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override; 50 void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, 51 uint64_t Value, bool IsPCRel) const override; 52 bool mayNeedRelaxation(const MCInst &Inst) const override { 53 return false; 54 } 55 bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value, 56 const MCRelaxableFragment *Fragment, 57 const MCAsmLayout &Layout) const override { 58 return false; 59 } 60 void relaxInstruction(const MCInst &Inst, MCInst &Res) const override { 61 llvm_unreachable("SystemZ does do not have assembler relaxation"); 62 } 63 bool writeNopData(uint64_t Count, MCObjectWriter *OW) const override; 64 MCObjectWriter *createObjectWriter(raw_ostream &OS) const override { 65 return createSystemZObjectWriter(OS, OSABI); 66 } 67 }; 68 } // end anonymous namespace 69 70 const MCFixupKindInfo & 71 SystemZMCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const { 72 const static MCFixupKindInfo Infos[SystemZ::NumTargetFixupKinds] = { 73 { "FK_390_PC16DBL", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, 74 { "FK_390_PC32DBL", 0, 32, MCFixupKindInfo::FKF_IsPCRel }, 75 { "FK_390_PLT16DBL", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, 76 { "FK_390_PLT32DBL", 0, 32, MCFixupKindInfo::FKF_IsPCRel } 77 }; 78 79 if (Kind < FirstTargetFixupKind) 80 return MCAsmBackend::getFixupKindInfo(Kind); 81 82 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && 83 "Invalid kind!"); 84 return Infos[Kind - FirstTargetFixupKind]; 85 } 86 87 void SystemZMCAsmBackend::applyFixup(const MCFixup &Fixup, char *Data, 88 unsigned DataSize, uint64_t Value, 89 bool IsPCRel) const { 90 MCFixupKind Kind = Fixup.getKind(); 91 unsigned Offset = Fixup.getOffset(); 92 unsigned Size = (getFixupKindInfo(Kind).TargetSize + 7) / 8; 93 94 assert(Offset + Size <= DataSize && "Invalid fixup offset!"); 95 96 // Big-endian insertion of Size bytes. 97 Value = extractBitsForFixup(Kind, Value); 98 unsigned ShiftValue = (Size * 8) - 8; 99 for (unsigned I = 0; I != Size; ++I) { 100 Data[Offset + I] |= uint8_t(Value >> ShiftValue); 101 ShiftValue -= 8; 102 } 103 } 104 105 bool SystemZMCAsmBackend::writeNopData(uint64_t Count, 106 MCObjectWriter *OW) const { 107 for (uint64_t I = 0; I != Count; ++I) 108 OW->Write8(7); 109 return true; 110 } 111 112 MCAsmBackend *llvm::createSystemZMCAsmBackend(const Target &T, 113 const MCRegisterInfo &MRI, 114 StringRef TT, StringRef CPU) { 115 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS()); 116 return new SystemZMCAsmBackend(OSABI); 117 } 118
