| //===-- MipsELFObjectWriter.cpp - Mips ELF Writer -------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "MCTargetDesc/MipsBaseInfo.h" |
| #include "MCTargetDesc/MipsFixupKinds.h" |
| #include "MCTargetDesc/MipsMCTargetDesc.h" |
| #include "llvm/MC/MCAssembler.h" |
| #include "llvm/MC/MCELFObjectWriter.h" |
| #include "llvm/MC/MCExpr.h" |
| #include "llvm/MC/MCSection.h" |
| #include "llvm/MC/MCValue.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include <list> |
| |
| using namespace llvm; |
| |
| namespace { |
| struct RelEntry { |
| RelEntry(const ELFRelocationEntry &R, const MCSymbol *S, int64_t O) : |
| Reloc(R), Sym(S), Offset(O) {} |
| ELFRelocationEntry Reloc; |
| const MCSymbol *Sym; |
| int64_t Offset; |
| }; |
| |
| typedef std::list<RelEntry> RelLs; |
| typedef RelLs::iterator RelLsIter; |
| |
| class MipsELFObjectWriter : public MCELFObjectTargetWriter { |
| public: |
| MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI, |
| bool _isN64, bool IsLittleEndian); |
| |
| virtual ~MipsELFObjectWriter(); |
| |
| virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, |
| bool IsPCRel, bool IsRelocWithSymbol, |
| int64_t Addend) const; |
| virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm, |
| const MCValue &Target, |
| const MCFragment &F, |
| const MCFixup &Fixup, |
| bool IsPCRel) const; |
| virtual void sortRelocs(const MCAssembler &Asm, |
| std::vector<ELFRelocationEntry> &Relocs); |
| }; |
| } |
| |
| MipsELFObjectWriter::MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI, |
| bool _isN64, bool IsLittleEndian) |
| : MCELFObjectTargetWriter(_is64Bit, OSABI, ELF::EM_MIPS, |
| /*HasRelocationAddend*/ (_isN64) ? true : false, |
| /*IsN64*/ _isN64) {} |
| |
| MipsELFObjectWriter::~MipsELFObjectWriter() {} |
| |
| const MCSymbol *MipsELFObjectWriter::ExplicitRelSym(const MCAssembler &Asm, |
| const MCValue &Target, |
| const MCFragment &F, |
| const MCFixup &Fixup, |
| bool IsPCRel) const { |
| assert(Target.getSymA() && "SymA cannot be 0."); |
| const MCSymbol &Sym = Target.getSymA()->getSymbol().AliasedSymbol(); |
| |
| if (Sym.getSection().getKind().isMergeableCString() || |
| Sym.getSection().getKind().isMergeableConst()) |
| return &Sym; |
| |
| return NULL; |
| } |
| |
| unsigned MipsELFObjectWriter::GetRelocType(const MCValue &Target, |
| const MCFixup &Fixup, |
| bool IsPCRel, |
| bool IsRelocWithSymbol, |
| int64_t Addend) const { |
| // determine the type of the relocation |
| unsigned Type = (unsigned)ELF::R_MIPS_NONE; |
| unsigned Kind = (unsigned)Fixup.getKind(); |
| |
| switch (Kind) { |
| default: |
| llvm_unreachable("invalid fixup kind!"); |
| case FK_Data_4: |
| Type = ELF::R_MIPS_32; |
| break; |
| case FK_Data_8: |
| Type = ELF::R_MIPS_64; |
| break; |
| case FK_GPRel_4: |
| if (isN64()) { |
| Type = setRType((unsigned)ELF::R_MIPS_GPREL32, Type); |
| Type = setRType2((unsigned)ELF::R_MIPS_64, Type); |
| Type = setRType3((unsigned)ELF::R_MIPS_NONE, Type); |
| } |
| else |
| Type = ELF::R_MIPS_GPREL32; |
| break; |
| case Mips::fixup_Mips_GPREL16: |
| Type = ELF::R_MIPS_GPREL16; |
| break; |
| case Mips::fixup_Mips_26: |
| Type = ELF::R_MIPS_26; |
| break; |
| case Mips::fixup_Mips_CALL16: |
| Type = ELF::R_MIPS_CALL16; |
| break; |
| case Mips::fixup_Mips_GOT_Global: |
| case Mips::fixup_Mips_GOT_Local: |
| Type = ELF::R_MIPS_GOT16; |
| break; |
| case Mips::fixup_Mips_HI16: |
| Type = ELF::R_MIPS_HI16; |
| break; |
| case Mips::fixup_Mips_LO16: |
| Type = ELF::R_MIPS_LO16; |
| break; |
| case Mips::fixup_Mips_TLSGD: |
| Type = ELF::R_MIPS_TLS_GD; |
| break; |
| case Mips::fixup_Mips_GOTTPREL: |
| Type = ELF::R_MIPS_TLS_GOTTPREL; |
| break; |
| case Mips::fixup_Mips_TPREL_HI: |
| Type = ELF::R_MIPS_TLS_TPREL_HI16; |
| break; |
| case Mips::fixup_Mips_TPREL_LO: |
| Type = ELF::R_MIPS_TLS_TPREL_LO16; |
| break; |
| case Mips::fixup_Mips_TLSLDM: |
| Type = ELF::R_MIPS_TLS_LDM; |
| break; |
| case Mips::fixup_Mips_DTPREL_HI: |
| Type = ELF::R_MIPS_TLS_DTPREL_HI16; |
| break; |
| case Mips::fixup_Mips_DTPREL_LO: |
| Type = ELF::R_MIPS_TLS_DTPREL_LO16; |
| break; |
| case Mips::fixup_Mips_Branch_PCRel: |
| case Mips::fixup_Mips_PC16: |
| Type = ELF::R_MIPS_PC16; |
| break; |
| case Mips::fixup_Mips_GOT_PAGE: |
| Type = ELF::R_MIPS_GOT_PAGE; |
| break; |
| case Mips::fixup_Mips_GOT_OFST: |
| Type = ELF::R_MIPS_GOT_OFST; |
| break; |
| case Mips::fixup_Mips_GOT_DISP: |
| Type = ELF::R_MIPS_GOT_DISP; |
| break; |
| case Mips::fixup_Mips_GPOFF_HI: |
| Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type); |
| Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type); |
| Type = setRType3((unsigned)ELF::R_MIPS_HI16, Type); |
| break; |
| case Mips::fixup_Mips_GPOFF_LO: |
| Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type); |
| Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type); |
| Type = setRType3((unsigned)ELF::R_MIPS_LO16, Type); |
| break; |
| case Mips::fixup_Mips_HIGHER: |
| Type = ELF::R_MIPS_HIGHER; |
| break; |
| case Mips::fixup_Mips_HIGHEST: |
| Type = ELF::R_MIPS_HIGHEST; |
| break; |
| case Mips::fixup_Mips_GOT_HI16: |
| Type = ELF::R_MIPS_GOT_HI16; |
| break; |
| case Mips::fixup_Mips_GOT_LO16: |
| Type = ELF::R_MIPS_GOT_LO16; |
| break; |
| case Mips::fixup_Mips_CALL_HI16: |
| Type = ELF::R_MIPS_CALL_HI16; |
| break; |
| case Mips::fixup_Mips_CALL_LO16: |
| Type = ELF::R_MIPS_CALL_LO16; |
| break; |
| } |
| return Type; |
| } |
| |
| // Return true if R is either a GOT16 against a local symbol or HI16. |
| static bool NeedsMatchingLo(const MCAssembler &Asm, const RelEntry &R) { |
| if (!R.Sym) |
| return false; |
| |
| MCSymbolData &SD = Asm.getSymbolData(R.Sym->AliasedSymbol()); |
| |
| return ((R.Reloc.Type == ELF::R_MIPS_GOT16) && !SD.isExternal()) || |
| (R.Reloc.Type == ELF::R_MIPS_HI16); |
| } |
| |
| static bool HasMatchingLo(const MCAssembler &Asm, RelLsIter I, RelLsIter Last) { |
| if (I == Last) |
| return false; |
| |
| RelLsIter Hi = I++; |
| |
| return (I->Reloc.Type == ELF::R_MIPS_LO16) && (Hi->Sym == I->Sym) && |
| (Hi->Offset == I->Offset); |
| } |
| |
| static bool HasSameSymbol(const RelEntry &R0, const RelEntry &R1) { |
| return R0.Sym == R1.Sym; |
| } |
| |
| static int CompareOffset(const RelEntry &R0, const RelEntry &R1) { |
| return (R0.Offset > R1.Offset) ? 1 : ((R0.Offset == R1.Offset) ? 0 : -1); |
| } |
| |
| void MipsELFObjectWriter::sortRelocs(const MCAssembler &Asm, |
| std::vector<ELFRelocationEntry> &Relocs) { |
| // Call the default function first. Relocations are sorted in descending |
| // order of r_offset. |
| MCELFObjectTargetWriter::sortRelocs(Asm, Relocs); |
| |
| RelLs RelocLs; |
| std::vector<RelLsIter> Unmatched; |
| |
| // Fill RelocLs. Traverse Relocs backwards so that relocations in RelocLs |
| // are in ascending order of r_offset. |
| for (std::vector<ELFRelocationEntry>::reverse_iterator R = Relocs.rbegin(); |
| R != Relocs.rend(); ++R) { |
| std::pair<const MCSymbolRefExpr*, int64_t> P = |
| MipsGetSymAndOffset(*R->Fixup); |
| RelocLs.push_back(RelEntry(*R, P.first ? &P.first->getSymbol() : 0, |
| P.second)); |
| } |
| |
| // Get list of unmatched HI16 and GOT16. |
| for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R) |
| if (NeedsMatchingLo(Asm, *R) && !HasMatchingLo(Asm, R, --RelocLs.end())) |
| Unmatched.push_back(R); |
| |
| // Insert unmatched HI16 and GOT16 immediately before their matching LO16. |
| for (std::vector<RelLsIter>::iterator U = Unmatched.begin(); |
| U != Unmatched.end(); ++U) { |
| RelLsIter LoPos = RelocLs.end(), HiPos = *U; |
| bool MatchedLo = false; |
| |
| for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R) { |
| if ((R->Reloc.Type == ELF::R_MIPS_LO16) && HasSameSymbol(*HiPos, *R) && |
| (CompareOffset(*R, *HiPos) >= 0) && |
| ((LoPos == RelocLs.end()) || ((CompareOffset(*R, *LoPos) < 0)) || |
| (!MatchedLo && !CompareOffset(*R, *LoPos)))) |
| LoPos = R; |
| |
| MatchedLo = NeedsMatchingLo(Asm, *R) && |
| HasMatchingLo(Asm, R, --RelocLs.end()); |
| } |
| |
| // If a matching LoPos was found, move HiPos and insert it before LoPos. |
| // Make the offsets of HiPos and LoPos match. |
| if (LoPos != RelocLs.end()) { |
| HiPos->Offset = LoPos->Offset; |
| RelocLs.insert(LoPos, *HiPos); |
| RelocLs.erase(HiPos); |
| } |
| } |
| |
| // Put the sorted list back in reverse order. |
| assert(Relocs.size() == RelocLs.size()); |
| unsigned I = RelocLs.size(); |
| |
| for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R) |
| Relocs[--I] = R->Reloc; |
| } |
| |
| MCObjectWriter *llvm::createMipsELFObjectWriter(raw_ostream &OS, |
| uint8_t OSABI, |
| bool IsLittleEndian, |
| bool Is64Bit) { |
| MCELFObjectTargetWriter *MOTW = new MipsELFObjectWriter(Is64Bit, OSABI, |
| (Is64Bit) ? true : false, |
| IsLittleEndian); |
| return createELFObjectWriter(MOTW, OS, IsLittleEndian); |
| } |