1 //===-- MipsELFObjectWriter.cpp - Mips ELF Writer -------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "MCTargetDesc/MipsBaseInfo.h"
11 #include "MCTargetDesc/MipsFixupKinds.h"
12 #include "MCTargetDesc/MipsMCTargetDesc.h"
13 #include "llvm/MC/MCAssembler.h"
14 #include "llvm/MC/MCELFObjectWriter.h"
15 #include "llvm/MC/MCExpr.h"
16 #include "llvm/MC/MCSection.h"
17 #include "llvm/MC/MCValue.h"
18 #include "llvm/Support/ErrorHandling.h"
25 RelEntry(const ELFRelocationEntry &R, const MCSymbol *S, int64_t O) :
26 Reloc(R), Sym(S), Offset(O) {}
27 ELFRelocationEntry Reloc;
32 typedef std::list<RelEntry> RelLs;
33 typedef RelLs::iterator RelLsIter;
35 class MipsELFObjectWriter : public MCELFObjectTargetWriter {
37 MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI, bool _isN64);
39 virtual ~MipsELFObjectWriter();
41 virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
42 bool IsPCRel, bool IsRelocWithSymbol,
43 int64_t Addend) const;
44 virtual unsigned getEFlags() const;
45 virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
46 const MCValue &Target,
50 virtual void sortRelocs(const MCAssembler &Asm,
51 std::vector<ELFRelocationEntry> &Relocs);
55 MipsELFObjectWriter::MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI,
57 : MCELFObjectTargetWriter(_is64Bit, OSABI, ELF::EM_MIPS,
58 /*HasRelocationAddend*/ false,
61 MipsELFObjectWriter::~MipsELFObjectWriter() {}
63 // FIXME: get the real EABI Version from the Subtarget class.
64 unsigned MipsELFObjectWriter::getEFlags() const {
66 // FIXME: We can't tell if we are PIC (dynamic) or CPIC (static)
67 unsigned Flag = ELF::EF_MIPS_NOREORDER;
70 Flag |= ELF::EF_MIPS_ARCH_64R2;
72 Flag |= ELF::EF_MIPS_ARCH_32R2;
76 const MCSymbol *MipsELFObjectWriter::ExplicitRelSym(const MCAssembler &Asm,
77 const MCValue &Target,
81 assert(Target.getSymA() && "SymA cannot be 0.");
82 const MCSymbol &Sym = Target.getSymA()->getSymbol().AliasedSymbol();
84 if (Sym.getSection().getKind().isMergeableCString() ||
85 Sym.getSection().getKind().isMergeableConst())
91 unsigned MipsELFObjectWriter::GetRelocType(const MCValue &Target,
94 bool IsRelocWithSymbol,
95 int64_t Addend) const {
96 // determine the type of the relocation
97 unsigned Type = (unsigned)ELF::R_MIPS_NONE;
98 unsigned Kind = (unsigned)Fixup.getKind();
102 llvm_unreachable("invalid fixup kind!");
104 Type = ELF::R_MIPS_32;
107 Type = ELF::R_MIPS_GPREL32;
109 case Mips::fixup_Mips_GPREL16:
110 Type = ELF::R_MIPS_GPREL16;
112 case Mips::fixup_Mips_26:
113 Type = ELF::R_MIPS_26;
115 case Mips::fixup_Mips_CALL16:
116 Type = ELF::R_MIPS_CALL16;
118 case Mips::fixup_Mips_GOT_Global:
119 case Mips::fixup_Mips_GOT_Local:
120 Type = ELF::R_MIPS_GOT16;
122 case Mips::fixup_Mips_HI16:
123 Type = ELF::R_MIPS_HI16;
125 case Mips::fixup_Mips_LO16:
126 Type = ELF::R_MIPS_LO16;
128 case Mips::fixup_Mips_TLSGD:
129 Type = ELF::R_MIPS_TLS_GD;
131 case Mips::fixup_Mips_GOTTPREL:
132 Type = ELF::R_MIPS_TLS_GOTTPREL;
134 case Mips::fixup_Mips_TPREL_HI:
135 Type = ELF::R_MIPS_TLS_TPREL_HI16;
137 case Mips::fixup_Mips_TPREL_LO:
138 Type = ELF::R_MIPS_TLS_TPREL_LO16;
140 case Mips::fixup_Mips_TLSLDM:
141 Type = ELF::R_MIPS_TLS_LDM;
143 case Mips::fixup_Mips_DTPREL_HI:
144 Type = ELF::R_MIPS_TLS_DTPREL_HI16;
146 case Mips::fixup_Mips_DTPREL_LO:
147 Type = ELF::R_MIPS_TLS_DTPREL_LO16;
149 case Mips::fixup_Mips_Branch_PCRel:
150 case Mips::fixup_Mips_PC16:
151 Type = ELF::R_MIPS_PC16;
153 case Mips::fixup_Mips_GOT_PAGE:
154 Type = ELF::R_MIPS_GOT_PAGE;
156 case Mips::fixup_Mips_GOT_OFST:
157 Type = ELF::R_MIPS_GOT_OFST;
159 case Mips::fixup_Mips_GOT_DISP:
160 Type = ELF::R_MIPS_GOT_DISP;
162 case Mips::fixup_Mips_GPOFF_HI:
163 Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
164 Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
165 Type = setRType3((unsigned)ELF::R_MIPS_HI16, Type);
167 case Mips::fixup_Mips_GPOFF_LO:
168 Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
169 Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
170 Type = setRType3((unsigned)ELF::R_MIPS_LO16, Type);
172 case Mips::fixup_Mips_HIGHER:
173 Type = ELF::R_MIPS_HIGHER;
175 case Mips::fixup_Mips_HIGHEST:
176 Type = ELF::R_MIPS_HIGHEST;
182 // Return true if R is either a GOT16 against a local symbol or HI16.
183 static bool NeedsMatchingLo(const MCAssembler &Asm, const RelEntry &R) {
187 MCSymbolData &SD = Asm.getSymbolData(R.Sym->AliasedSymbol());
189 return ((R.Reloc.Type == ELF::R_MIPS_GOT16) && !SD.isExternal()) ||
190 (R.Reloc.Type == ELF::R_MIPS_HI16);
193 static bool HasMatchingLo(const MCAssembler &Asm, RelLsIter I, RelLsIter Last) {
199 return (I->Reloc.Type == ELF::R_MIPS_LO16) && (Hi->Sym == I->Sym) &&
200 (Hi->Offset == I->Offset);
203 static bool HasSameSymbol(const RelEntry &R0, const RelEntry &R1) {
204 return R0.Sym == R1.Sym;
207 static int CompareOffset(const RelEntry &R0, const RelEntry &R1) {
208 return (R0.Offset > R1.Offset) ? 1 : ((R0.Offset == R1.Offset) ? 0 : -1);
211 void MipsELFObjectWriter::sortRelocs(const MCAssembler &Asm,
212 std::vector<ELFRelocationEntry> &Relocs) {
213 // Call the default function first. Relocations are sorted in descending
214 // order of r_offset.
215 MCELFObjectTargetWriter::sortRelocs(Asm, Relocs);
218 std::vector<RelLsIter> Unmatched;
220 // Fill RelocLs. Traverse Relocs backwards so that relocations in RelocLs
221 // are in ascending order of r_offset.
222 for (std::vector<ELFRelocationEntry>::reverse_iterator R = Relocs.rbegin();
223 R != Relocs.rend(); ++R) {
224 std::pair<const MCSymbolRefExpr*, int64_t> P =
225 MipsGetSymAndOffset(*R->Fixup);
226 RelocLs.push_back(RelEntry(*R, P.first ? &P.first->getSymbol() : 0,
230 // Get list of unmatched HI16 and GOT16.
231 for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R)
232 if (NeedsMatchingLo(Asm, *R) && !HasMatchingLo(Asm, R, --RelocLs.end()))
233 Unmatched.push_back(R);
235 // Insert unmatched HI16 and GOT16 immediately before their matching LO16.
236 for (std::vector<RelLsIter>::iterator U = Unmatched.begin();
237 U != Unmatched.end(); ++U) {
238 RelLsIter LoPos = RelocLs.end(), HiPos = *U;
239 bool MatchedLo = false;
241 for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R) {
242 if ((R->Reloc.Type == ELF::R_MIPS_LO16) && HasSameSymbol(*HiPos, *R) &&
243 (CompareOffset(*R, *HiPos) >= 0) &&
244 ((LoPos == RelocLs.end()) || ((CompareOffset(*R, *LoPos) < 0)) ||
245 (!MatchedLo && !CompareOffset(*R, *LoPos))))
248 MatchedLo = NeedsMatchingLo(Asm, *R) &&
249 HasMatchingLo(Asm, R, --RelocLs.end());
252 // If a matching LoPos was found, move HiPos and insert it before LoPos.
253 // Make the offsets of HiPos and LoPos match.
254 if (LoPos != RelocLs.end()) {
255 HiPos->Offset = LoPos->Offset;
256 RelocLs.insert(LoPos, *HiPos);
257 RelocLs.erase(HiPos);
261 // Put the sorted list back in reverse order.
262 assert(Relocs.size() == RelocLs.size());
263 unsigned I = RelocLs.size();
265 for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R)
266 Relocs[--I] = R->Reloc;
269 MCObjectWriter *llvm::createMipsELFObjectWriter(raw_ostream &OS,
273 MCELFObjectTargetWriter *MOTW = new MipsELFObjectWriter(Is64Bit, OSABI,
274 (Is64Bit) ? true : false);
275 return createELFObjectWriter(MOTW, OS, IsLittleEndian);