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,
38 bool _isN64, bool IsLittleEndian);
40 virtual ~MipsELFObjectWriter();
42 unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
43 bool IsPCRel) const override;
44 virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
45 const MCValue &Target,
49 virtual void sortRelocs(const MCAssembler &Asm,
50 std::vector<ELFRelocationEntry> &Relocs);
54 MipsELFObjectWriter::MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI,
55 bool _isN64, bool IsLittleEndian)
56 : MCELFObjectTargetWriter(_is64Bit, OSABI, ELF::EM_MIPS,
57 /*HasRelocationAddend*/ (_isN64) ? true : false,
60 MipsELFObjectWriter::~MipsELFObjectWriter() {}
62 const MCSymbol *MipsELFObjectWriter::ExplicitRelSym(const MCAssembler &Asm,
63 const MCValue &Target,
67 assert(Target.getSymA() && "SymA cannot be 0.");
68 const MCSymbol &Sym = Target.getSymA()->getSymbol().AliasedSymbol();
70 if (Sym.getSection().getKind().isMergeableCString() ||
71 Sym.getSection().getKind().isMergeableConst())
77 unsigned MipsELFObjectWriter::GetRelocType(const MCValue &Target,
80 // determine the type of the relocation
81 unsigned Type = (unsigned)ELF::R_MIPS_NONE;
82 unsigned Kind = (unsigned)Fixup.getKind();
86 llvm_unreachable("invalid fixup kind!");
88 Type = ELF::R_MIPS_32;
91 Type = ELF::R_MIPS_64;
95 Type = setRType((unsigned)ELF::R_MIPS_GPREL32, Type);
96 Type = setRType2((unsigned)ELF::R_MIPS_64, Type);
97 Type = setRType3((unsigned)ELF::R_MIPS_NONE, Type);
100 Type = ELF::R_MIPS_GPREL32;
102 case Mips::fixup_Mips_GPREL16:
103 Type = ELF::R_MIPS_GPREL16;
105 case Mips::fixup_Mips_26:
106 Type = ELF::R_MIPS_26;
108 case Mips::fixup_Mips_CALL16:
109 Type = ELF::R_MIPS_CALL16;
111 case Mips::fixup_Mips_GOT_Global:
112 case Mips::fixup_Mips_GOT_Local:
113 Type = ELF::R_MIPS_GOT16;
115 case Mips::fixup_Mips_HI16:
116 Type = ELF::R_MIPS_HI16;
118 case Mips::fixup_Mips_LO16:
119 Type = ELF::R_MIPS_LO16;
121 case Mips::fixup_Mips_TLSGD:
122 Type = ELF::R_MIPS_TLS_GD;
124 case Mips::fixup_Mips_GOTTPREL:
125 Type = ELF::R_MIPS_TLS_GOTTPREL;
127 case Mips::fixup_Mips_TPREL_HI:
128 Type = ELF::R_MIPS_TLS_TPREL_HI16;
130 case Mips::fixup_Mips_TPREL_LO:
131 Type = ELF::R_MIPS_TLS_TPREL_LO16;
133 case Mips::fixup_Mips_TLSLDM:
134 Type = ELF::R_MIPS_TLS_LDM;
136 case Mips::fixup_Mips_DTPREL_HI:
137 Type = ELF::R_MIPS_TLS_DTPREL_HI16;
139 case Mips::fixup_Mips_DTPREL_LO:
140 Type = ELF::R_MIPS_TLS_DTPREL_LO16;
142 case Mips::fixup_Mips_Branch_PCRel:
143 case Mips::fixup_Mips_PC16:
144 Type = ELF::R_MIPS_PC16;
146 case Mips::fixup_Mips_GOT_PAGE:
147 Type = ELF::R_MIPS_GOT_PAGE;
149 case Mips::fixup_Mips_GOT_OFST:
150 Type = ELF::R_MIPS_GOT_OFST;
152 case Mips::fixup_Mips_GOT_DISP:
153 Type = ELF::R_MIPS_GOT_DISP;
155 case Mips::fixup_Mips_GPOFF_HI:
156 Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
157 Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
158 Type = setRType3((unsigned)ELF::R_MIPS_HI16, Type);
160 case Mips::fixup_Mips_GPOFF_LO:
161 Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
162 Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
163 Type = setRType3((unsigned)ELF::R_MIPS_LO16, Type);
165 case Mips::fixup_Mips_HIGHER:
166 Type = ELF::R_MIPS_HIGHER;
168 case Mips::fixup_Mips_HIGHEST:
169 Type = ELF::R_MIPS_HIGHEST;
171 case Mips::fixup_Mips_GOT_HI16:
172 Type = ELF::R_MIPS_GOT_HI16;
174 case Mips::fixup_Mips_GOT_LO16:
175 Type = ELF::R_MIPS_GOT_LO16;
177 case Mips::fixup_Mips_CALL_HI16:
178 Type = ELF::R_MIPS_CALL_HI16;
180 case Mips::fixup_Mips_CALL_LO16:
181 Type = ELF::R_MIPS_CALL_LO16;
183 case Mips::fixup_MICROMIPS_26_S1:
184 Type = ELF::R_MICROMIPS_26_S1;
186 case Mips::fixup_MICROMIPS_HI16:
187 Type = ELF::R_MICROMIPS_HI16;
189 case Mips::fixup_MICROMIPS_LO16:
190 Type = ELF::R_MICROMIPS_LO16;
192 case Mips::fixup_MICROMIPS_GOT16:
193 Type = ELF::R_MICROMIPS_GOT16;
195 case Mips::fixup_MICROMIPS_PC16_S1:
196 Type = ELF::R_MICROMIPS_PC16_S1;
198 case Mips::fixup_MICROMIPS_CALL16:
199 Type = ELF::R_MICROMIPS_CALL16;
201 case Mips::fixup_MICROMIPS_GOT_DISP:
202 Type = ELF::R_MICROMIPS_GOT_DISP;
204 case Mips::fixup_MICROMIPS_GOT_PAGE:
205 Type = ELF::R_MICROMIPS_GOT_PAGE;
207 case Mips::fixup_MICROMIPS_GOT_OFST:
208 Type = ELF::R_MICROMIPS_GOT_OFST;
210 case Mips::fixup_MICROMIPS_TLS_GD:
211 Type = ELF::R_MICROMIPS_TLS_GD;
213 case Mips::fixup_MICROMIPS_TLS_LDM:
214 Type = ELF::R_MICROMIPS_TLS_LDM;
216 case Mips::fixup_MICROMIPS_TLS_DTPREL_HI16:
217 Type = ELF::R_MICROMIPS_TLS_DTPREL_HI16;
219 case Mips::fixup_MICROMIPS_TLS_DTPREL_LO16:
220 Type = ELF::R_MICROMIPS_TLS_DTPREL_LO16;
222 case Mips::fixup_MICROMIPS_TLS_TPREL_HI16:
223 Type = ELF::R_MICROMIPS_TLS_TPREL_HI16;
225 case Mips::fixup_MICROMIPS_TLS_TPREL_LO16:
226 Type = ELF::R_MICROMIPS_TLS_TPREL_LO16;
232 // Return true if R is either a GOT16 against a local symbol or HI16.
233 static bool NeedsMatchingLo(const MCAssembler &Asm, const RelEntry &R) {
237 MCSymbolData &SD = Asm.getSymbolData(R.Sym->AliasedSymbol());
239 return ((R.Reloc.Type == ELF::R_MIPS_GOT16) && !SD.isExternal()) ||
240 (R.Reloc.Type == ELF::R_MIPS_HI16);
243 static bool HasMatchingLo(const MCAssembler &Asm, RelLsIter I, RelLsIter Last) {
249 return (I->Reloc.Type == ELF::R_MIPS_LO16) && (Hi->Sym == I->Sym) &&
250 (Hi->Offset == I->Offset);
253 static bool HasSameSymbol(const RelEntry &R0, const RelEntry &R1) {
254 return R0.Sym == R1.Sym;
257 static int CompareOffset(const RelEntry &R0, const RelEntry &R1) {
258 return (R0.Offset > R1.Offset) ? 1 : ((R0.Offset == R1.Offset) ? 0 : -1);
261 void MipsELFObjectWriter::sortRelocs(const MCAssembler &Asm,
262 std::vector<ELFRelocationEntry> &Relocs) {
263 // Call the default function first. Relocations are sorted in descending
264 // order of r_offset.
265 MCELFObjectTargetWriter::sortRelocs(Asm, Relocs);
268 std::vector<RelLsIter> Unmatched;
270 // Fill RelocLs. Traverse Relocs backwards so that relocations in RelocLs
271 // are in ascending order of r_offset.
272 for (std::vector<ELFRelocationEntry>::reverse_iterator R = Relocs.rbegin();
273 R != Relocs.rend(); ++R) {
274 std::pair<const MCSymbolRefExpr*, int64_t> P =
275 MipsGetSymAndOffset(*R->Fixup);
276 RelocLs.push_back(RelEntry(*R, P.first ? &P.first->getSymbol() : 0,
280 // Get list of unmatched HI16 and GOT16.
281 for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R)
282 if (NeedsMatchingLo(Asm, *R) && !HasMatchingLo(Asm, R, --RelocLs.end()))
283 Unmatched.push_back(R);
285 // Insert unmatched HI16 and GOT16 immediately before their matching LO16.
286 for (std::vector<RelLsIter>::iterator U = Unmatched.begin();
287 U != Unmatched.end(); ++U) {
288 RelLsIter LoPos = RelocLs.end(), HiPos = *U;
289 bool MatchedLo = false;
291 for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R) {
292 if ((R->Reloc.Type == ELF::R_MIPS_LO16) && HasSameSymbol(*HiPos, *R) &&
293 (CompareOffset(*R, *HiPos) >= 0) &&
294 ((LoPos == RelocLs.end()) || ((CompareOffset(*R, *LoPos) < 0)) ||
295 (!MatchedLo && !CompareOffset(*R, *LoPos))))
298 MatchedLo = NeedsMatchingLo(Asm, *R) &&
299 HasMatchingLo(Asm, R, --RelocLs.end());
302 // If a matching LoPos was found, move HiPos and insert it before LoPos.
303 // Make the offsets of HiPos and LoPos match.
304 if (LoPos != RelocLs.end()) {
305 HiPos->Offset = LoPos->Offset;
306 RelocLs.insert(LoPos, *HiPos);
307 RelocLs.erase(HiPos);
311 // Put the sorted list back in reverse order.
312 assert(Relocs.size() == RelocLs.size());
313 unsigned I = RelocLs.size();
315 for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R)
316 Relocs[--I] = R->Reloc;
319 MCObjectWriter *llvm::createMipsELFObjectWriter(raw_ostream &OS,
323 MCELFObjectTargetWriter *MOTW = new MipsELFObjectWriter(Is64Bit, OSABI,
324 (Is64Bit) ? true : false,
326 return createELFObjectWriter(MOTW, OS, IsLittleEndian);