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 return (int64_t)Value / 2; 31 32 case SystemZ::FK_390_TLS_CALL: 33 return 0; 34 } 35 36 llvm_unreachable("Unknown fixup kind!"); 37 } 38 39 namespace { 40 class SystemZMCAsmBackend : public MCAsmBackend { 41 uint8_t OSABI; 42 public: 43 SystemZMCAsmBackend(uint8_t osABI) 44 : OSABI(osABI) {} 45 46 // Override MCAsmBackend 47 unsigned getNumFixupKinds() const override { 48 return SystemZ::NumTargetFixupKinds; 49 } 50 const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override; 51 void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, 52 uint64_t Value, bool IsPCRel) const override; 53 bool mayNeedRelaxation(const MCInst &Inst) const override { 54 return false; 55 } 56 bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value, 57 const MCRelaxableFragment *Fragment, 58 const MCAsmLayout &Layout) const override { 59 return false; 60 } 61 void relaxInstruction(const MCInst &Inst, const MCSubtargetInfo &STI, 62 MCInst &Res) const override { 63 llvm_unreachable("SystemZ does do not have assembler relaxation"); 64 } 65 bool writeNopData(uint64_t Count, MCObjectWriter *OW) const override; 66 MCObjectWriter *createObjectWriter(raw_pwrite_stream &OS) const override { 67 return createSystemZObjectWriter(OS, OSABI); 68 } 69 }; 70 } // end anonymous namespace 71 72 const MCFixupKindInfo & 73 SystemZMCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const { 74 const static MCFixupKindInfo Infos[SystemZ::NumTargetFixupKinds] = { 75 { "FK_390_PC16DBL", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, 76 { "FK_390_PC32DBL", 0, 32, MCFixupKindInfo::FKF_IsPCRel }, 77 { "FK_390_TLS_CALL", 0, 0, 0 } 78 }; 79 80 if (Kind < FirstTargetFixupKind) 81 return MCAsmBackend::getFixupKindInfo(Kind); 82 83 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && 84 "Invalid kind!"); 85 return Infos[Kind - FirstTargetFixupKind]; 86 } 87 88 void SystemZMCAsmBackend::applyFixup(const MCFixup &Fixup, char *Data, 89 unsigned DataSize, uint64_t Value, 90 bool IsPCRel) const { 91 MCFixupKind Kind = Fixup.getKind(); 92 unsigned Offset = Fixup.getOffset(); 93 unsigned Size = (getFixupKindInfo(Kind).TargetSize + 7) / 8; 94 95 assert(Offset + Size <= DataSize && "Invalid fixup offset!"); 96 97 // Big-endian insertion of Size bytes. 98 Value = extractBitsForFixup(Kind, Value); 99 unsigned ShiftValue = (Size * 8) - 8; 100 for (unsigned I = 0; I != Size; ++I) { 101 Data[Offset + I] |= uint8_t(Value >> ShiftValue); 102 ShiftValue -= 8; 103 } 104 } 105 106 bool SystemZMCAsmBackend::writeNopData(uint64_t Count, 107 MCObjectWriter *OW) const { 108 for (uint64_t I = 0; I != Count; ++I) 109 OW->write8(7); 110 return true; 111 } 112 113 MCAsmBackend *llvm::createSystemZMCAsmBackend(const Target &T, 114 const MCRegisterInfo &MRI, 115 const Triple &TT, StringRef CPU) { 116 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS()); 117 return new SystemZMCAsmBackend(OSABI); 118 } 119
