xref: /llvm-project/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp (revision 2225d9415f65bf84657cf42f6c1504dda3867bca)
1 //===-- MipsELFObjectWriter.cpp - Mips ELF Writer -------------------------===//
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 <algorithm>
11 #include <list>
12 #include "MCTargetDesc/MipsBaseInfo.h"
13 #include "MCTargetDesc/MipsFixupKinds.h"
14 #include "MCTargetDesc/MipsMCExpr.h"
15 #include "MCTargetDesc/MipsMCTargetDesc.h"
16 #include "llvm/ADT/STLExtras.h"
17 #include "llvm/MC/MCAssembler.h"
18 #include "llvm/MC/MCELFObjectWriter.h"
19 #include "llvm/MC/MCExpr.h"
20 #include "llvm/MC/MCSection.h"
21 #include "llvm/MC/MCSymbolELF.h"
22 #include "llvm/MC/MCValue.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/ErrorHandling.h"
25 
26 #define DEBUG_TYPE "mips-elf-object-writer"
27 
28 using namespace llvm;
29 
30 namespace {
31 /// Holds additional information needed by the relocation ordering algorithm.
32 struct MipsRelocationEntry {
33   const ELFRelocationEntry R; ///< The relocation.
34   bool Matched;               ///< Is this relocation part of a match.
35 
36   MipsRelocationEntry(const ELFRelocationEntry &R) : R(R), Matched(false) {}
37 
38   void print(raw_ostream &Out) const {
39     R.print(Out);
40     Out << ", Matched=" << Matched;
41   }
42 };
43 
44 #ifndef NDEBUG
45 raw_ostream &operator<<(raw_ostream &OS, const MipsRelocationEntry &RHS) {
46   RHS.print(OS);
47   return OS;
48 }
49 #endif
50 
51 class MipsELFObjectWriter : public MCELFObjectTargetWriter {
52 public:
53   MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI, bool _isN64,
54                       bool IsLittleEndian);
55 
56   ~MipsELFObjectWriter() override;
57 
58   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
59                         const MCFixup &Fixup, bool IsPCRel) const override;
60   bool needsRelocateWithSymbol(const MCSymbol &Sym,
61                                unsigned Type) const override;
62   virtual void sortRelocs(const MCAssembler &Asm,
63                           std::vector<ELFRelocationEntry> &Relocs) override;
64 };
65 
66 /// Copy elements in the range [First, Last) to d1 when the predicate is true or
67 /// d2 when the predicate is false. This is essentially both std::copy_if and
68 /// std::remove_copy_if combined into a single pass.
69 template <class InputIt, class OutputIt1, class OutputIt2, class UnaryPredicate>
70 std::pair<OutputIt1, OutputIt2> copy_if_else(InputIt First, InputIt Last,
71                                              OutputIt1 d1, OutputIt2 d2,
72                                              UnaryPredicate Predicate) {
73   for (InputIt I = First; I != Last; ++I) {
74     if (Predicate(*I)) {
75       *d1 = *I;
76       d1++;
77     } else {
78       *d2 = *I;
79       d2++;
80     }
81   }
82 
83   return std::make_pair(d1, d2);
84 }
85 
86 /// The possible results of the Predicate function used by find_best.
87 enum FindBestPredicateResult {
88   FindBest_NoMatch = 0,  ///< The current element is not a match.
89   FindBest_Match,        ///< The current element is a match but better ones are
90                          ///  possible.
91   FindBest_PerfectMatch, ///< The current element is an unbeatable match.
92 };
93 
94 /// Find the best match in the range [First, Last).
95 ///
96 /// An element matches when Predicate(X) returns FindBest_Match or
97 /// FindBest_PerfectMatch. A value of FindBest_PerfectMatch also terminates
98 /// the search. BetterThan(A, B) is a comparator that returns true when A is a
99 /// better match than B. The return value is the position of the best match.
100 ///
101 /// This is similar to std::find_if but finds the best of multiple possible
102 /// matches.
103 template <class InputIt, class UnaryPredicate, class Comparator>
104 InputIt find_best(InputIt First, InputIt Last, UnaryPredicate Predicate,
105                   Comparator BetterThan) {
106   InputIt Best = Last;
107 
108   for (InputIt I = First; I != Last; ++I) {
109     unsigned Matched = Predicate(*I);
110     if (Matched != FindBest_NoMatch) {
111       DEBUG(dbgs() << std::distance(First, I) << " is a match (";
112             I->print(dbgs()); dbgs() << ")\n");
113       if (Best == Last || BetterThan(*I, *Best)) {
114         DEBUG(dbgs() << ".. and it beats the last one\n");
115         Best = I;
116       }
117     }
118     if (Matched == FindBest_PerfectMatch) {
119       DEBUG(dbgs() << ".. and it is unbeatable\n");
120       break;
121     }
122   }
123 
124   return Best;
125 }
126 
127 /// Determine the low relocation that matches the given relocation.
128 /// If the relocation does not need a low relocation then the return value
129 /// is ELF::R_MIPS_NONE.
130 ///
131 /// The relocations that need a matching low part are
132 /// R_(MIPS|MICROMIPS|MIPS16)_HI16 for all symbols and
133 /// R_(MIPS|MICROMIPS|MIPS16)_GOT16 for local symbols only.
134 static unsigned getMatchingLoType(const ELFRelocationEntry &Reloc) {
135   unsigned Type = Reloc.Type;
136   if (Type == ELF::R_MIPS_HI16)
137     return ELF::R_MIPS_LO16;
138   if (Type == ELF::R_MICROMIPS_HI16)
139     return ELF::R_MICROMIPS_LO16;
140   if (Type == ELF::R_MIPS16_HI16)
141     return ELF::R_MIPS16_LO16;
142 
143   if (Reloc.OriginalSymbol->getBinding() != ELF::STB_LOCAL)
144     return ELF::R_MIPS_NONE;
145 
146   if (Type == ELF::R_MIPS_GOT16)
147     return ELF::R_MIPS_LO16;
148   if (Type == ELF::R_MICROMIPS_GOT16)
149     return ELF::R_MICROMIPS_LO16;
150   if (Type == ELF::R_MIPS16_GOT16)
151     return ELF::R_MIPS16_LO16;
152 
153   return ELF::R_MIPS_NONE;
154 }
155 
156 /// Determine whether a relocation (X) matches the one given in R.
157 ///
158 /// A relocation matches if:
159 /// - It's type matches that of a corresponding low part. This is provided in
160 ///   MatchingType for efficiency.
161 /// - It's based on the same symbol.
162 /// - It's offset of greater or equal to that of the one given in R.
163 ///   It should be noted that this rule assumes the programmer does not use
164 ///   offsets that exceed the alignment of the symbol. The carry-bit will be
165 ///   incorrect if this is not true.
166 ///
167 /// A matching relocation is unbeatable if:
168 /// - It is not already involved in a match.
169 /// - It's offset is exactly that of the one given in R.
170 static FindBestPredicateResult isMatchingReloc(const MipsRelocationEntry &X,
171                                                const ELFRelocationEntry &R,
172                                                unsigned MatchingType) {
173   if (X.R.Type == MatchingType && X.R.OriginalSymbol == R.OriginalSymbol) {
174     if (!X.Matched &&
175         X.R.OriginalAddend == R.OriginalAddend)
176       return FindBest_PerfectMatch;
177     else if (X.R.OriginalAddend >= R.OriginalAddend)
178       return FindBest_Match;
179   }
180   return FindBest_NoMatch;
181 }
182 
183 /// Determine whether Candidate or PreviousBest is the better match.
184 /// The return value is true if Candidate is the better match.
185 ///
186 /// A matching relocation is a better match if:
187 /// - It has a smaller addend.
188 /// - It is not already involved in a match.
189 static bool compareMatchingRelocs(const MipsRelocationEntry &Candidate,
190                                   const MipsRelocationEntry &PreviousBest) {
191   if (Candidate.R.OriginalAddend != PreviousBest.R.OriginalAddend)
192     return Candidate.R.OriginalAddend < PreviousBest.R.OriginalAddend;
193   return PreviousBest.Matched && !Candidate.Matched;
194 }
195 
196 #ifndef NDEBUG
197 /// Print all the relocations.
198 template <class Container>
199 static void dumpRelocs(const char *Prefix, const Container &Relocs) {
200   for (const auto &R : Relocs)
201     dbgs() << Prefix << R << "\n";
202 }
203 #endif
204 
205 } // end anonymous namespace
206 
207 MipsELFObjectWriter::MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI,
208                                          bool _isN64, bool IsLittleEndian)
209     : MCELFObjectTargetWriter(_is64Bit, OSABI, ELF::EM_MIPS,
210                               /*HasRelocationAddend*/ _isN64,
211                               /*IsN64*/ _isN64) {}
212 
213 MipsELFObjectWriter::~MipsELFObjectWriter() {}
214 
215 unsigned MipsELFObjectWriter::getRelocType(MCContext &Ctx,
216                                            const MCValue &Target,
217                                            const MCFixup &Fixup,
218                                            bool IsPCRel) const {
219   // Determine the type of the relocation.
220   unsigned Kind = (unsigned)Fixup.getKind();
221 
222   switch (Kind) {
223   case Mips::fixup_Mips_NONE:
224     return ELF::R_MIPS_NONE;
225   case Mips::fixup_Mips_16:
226   case FK_Data_2:
227     return IsPCRel ? ELF::R_MIPS_PC16 : ELF::R_MIPS_16;
228   case Mips::fixup_Mips_32:
229   case FK_Data_4:
230     return IsPCRel ? ELF::R_MIPS_PC32 : ELF::R_MIPS_32;
231   }
232 
233   if (IsPCRel) {
234     switch (Kind) {
235     case Mips::fixup_Mips_Branch_PCRel:
236     case Mips::fixup_Mips_PC16:
237       return ELF::R_MIPS_PC16;
238     case Mips::fixup_MICROMIPS_PC7_S1:
239       return ELF::R_MICROMIPS_PC7_S1;
240     case Mips::fixup_MICROMIPS_PC10_S1:
241       return ELF::R_MICROMIPS_PC10_S1;
242     case Mips::fixup_MICROMIPS_PC16_S1:
243       return ELF::R_MICROMIPS_PC16_S1;
244     case Mips::fixup_MICROMIPS_PC26_S1:
245       return ELF::R_MICROMIPS_PC26_S1;
246     case Mips::fixup_MICROMIPS_PC19_S2:
247       return ELF::R_MICROMIPS_PC19_S2;
248     case Mips::fixup_MICROMIPS_PC18_S3:
249       return ELF::R_MICROMIPS_PC18_S3;
250     case Mips::fixup_MIPS_PC19_S2:
251       return ELF::R_MIPS_PC19_S2;
252     case Mips::fixup_MIPS_PC18_S3:
253       return ELF::R_MIPS_PC18_S3;
254     case Mips::fixup_MIPS_PC21_S2:
255       return ELF::R_MIPS_PC21_S2;
256     case Mips::fixup_MIPS_PC26_S2:
257       return ELF::R_MIPS_PC26_S2;
258     case Mips::fixup_MIPS_PCHI16:
259       return ELF::R_MIPS_PCHI16;
260     case Mips::fixup_MIPS_PCLO16:
261       return ELF::R_MIPS_PCLO16;
262     }
263 
264     llvm_unreachable("invalid PC-relative fixup kind!");
265   }
266 
267   switch (Kind) {
268   case Mips::fixup_Mips_64:
269   case FK_Data_8:
270     return ELF::R_MIPS_64;
271   case FK_GPRel_4:
272     if (isN64()) {
273       unsigned Type = (unsigned)ELF::R_MIPS_NONE;
274       Type = setRType((unsigned)ELF::R_MIPS_GPREL32, Type);
275       Type = setRType2((unsigned)ELF::R_MIPS_64, Type);
276       Type = setRType3((unsigned)ELF::R_MIPS_NONE, Type);
277       return Type;
278     }
279     return ELF::R_MIPS_GPREL32;
280   case Mips::fixup_Mips_GPREL16:
281     return ELF::R_MIPS_GPREL16;
282   case Mips::fixup_Mips_26:
283     return ELF::R_MIPS_26;
284   case Mips::fixup_Mips_CALL16:
285     return ELF::R_MIPS_CALL16;
286   case Mips::fixup_Mips_GOT:
287     return ELF::R_MIPS_GOT16;
288   case Mips::fixup_Mips_HI16:
289     return ELF::R_MIPS_HI16;
290   case Mips::fixup_Mips_LO16:
291     return ELF::R_MIPS_LO16;
292   case Mips::fixup_Mips_TLSGD:
293     return ELF::R_MIPS_TLS_GD;
294   case Mips::fixup_Mips_GOTTPREL:
295     return ELF::R_MIPS_TLS_GOTTPREL;
296   case Mips::fixup_Mips_TPREL_HI:
297     return ELF::R_MIPS_TLS_TPREL_HI16;
298   case Mips::fixup_Mips_TPREL_LO:
299     return ELF::R_MIPS_TLS_TPREL_LO16;
300   case Mips::fixup_Mips_TLSLDM:
301     return ELF::R_MIPS_TLS_LDM;
302   case Mips::fixup_Mips_DTPREL_HI:
303     return ELF::R_MIPS_TLS_DTPREL_HI16;
304   case Mips::fixup_Mips_DTPREL_LO:
305     return ELF::R_MIPS_TLS_DTPREL_LO16;
306   case Mips::fixup_Mips_GOT_PAGE:
307     return ELF::R_MIPS_GOT_PAGE;
308   case Mips::fixup_Mips_GOT_OFST:
309     return ELF::R_MIPS_GOT_OFST;
310   case Mips::fixup_Mips_GOT_DISP:
311     return ELF::R_MIPS_GOT_DISP;
312   case Mips::fixup_Mips_GPOFF_HI: {
313     unsigned Type = (unsigned)ELF::R_MIPS_NONE;
314     Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
315     Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
316     Type = setRType3((unsigned)ELF::R_MIPS_HI16, Type);
317     return Type;
318   }
319   case Mips::fixup_Mips_GPOFF_LO: {
320     unsigned Type = (unsigned)ELF::R_MIPS_NONE;
321     Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
322     Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
323     Type = setRType3((unsigned)ELF::R_MIPS_LO16, Type);
324     return Type;
325   }
326   case Mips::fixup_Mips_HIGHER:
327     return ELF::R_MIPS_HIGHER;
328   case Mips::fixup_Mips_HIGHEST:
329     return ELF::R_MIPS_HIGHEST;
330   case Mips::fixup_Mips_GOT_HI16:
331     return ELF::R_MIPS_GOT_HI16;
332   case Mips::fixup_Mips_GOT_LO16:
333     return ELF::R_MIPS_GOT_LO16;
334   case Mips::fixup_Mips_CALL_HI16:
335     return ELF::R_MIPS_CALL_HI16;
336   case Mips::fixup_Mips_CALL_LO16:
337     return ELF::R_MIPS_CALL_LO16;
338   case Mips::fixup_MICROMIPS_26_S1:
339     return ELF::R_MICROMIPS_26_S1;
340   case Mips::fixup_MICROMIPS_HI16:
341     return ELF::R_MICROMIPS_HI16;
342   case Mips::fixup_MICROMIPS_LO16:
343     return ELF::R_MICROMIPS_LO16;
344   case Mips::fixup_MICROMIPS_GOT16:
345     return ELF::R_MICROMIPS_GOT16;
346   case Mips::fixup_MICROMIPS_CALL16:
347     return ELF::R_MICROMIPS_CALL16;
348   case Mips::fixup_MICROMIPS_GOT_DISP:
349     return ELF::R_MICROMIPS_GOT_DISP;
350   case Mips::fixup_MICROMIPS_GOT_PAGE:
351     return ELF::R_MICROMIPS_GOT_PAGE;
352   case Mips::fixup_MICROMIPS_GOT_OFST:
353     return ELF::R_MICROMIPS_GOT_OFST;
354   case Mips::fixup_MICROMIPS_TLS_GD:
355     return ELF::R_MICROMIPS_TLS_GD;
356   case Mips::fixup_MICROMIPS_TLS_LDM:
357     return ELF::R_MICROMIPS_TLS_LDM;
358   case Mips::fixup_MICROMIPS_TLS_DTPREL_HI16:
359     return ELF::R_MICROMIPS_TLS_DTPREL_HI16;
360   case Mips::fixup_MICROMIPS_TLS_DTPREL_LO16:
361     return ELF::R_MICROMIPS_TLS_DTPREL_LO16;
362   case Mips::fixup_MICROMIPS_TLS_TPREL_HI16:
363     return ELF::R_MICROMIPS_TLS_TPREL_HI16;
364   case Mips::fixup_MICROMIPS_TLS_TPREL_LO16:
365     return ELF::R_MICROMIPS_TLS_TPREL_LO16;
366   }
367 
368   llvm_unreachable("invalid fixup kind!");
369 }
370 
371 /// Sort relocation table entries by offset except where another order is
372 /// required by the MIPS ABI.
373 ///
374 /// MIPS has a few relocations that have an AHL component in the expression used
375 /// to evaluate them. This AHL component is an addend with the same number of
376 /// bits as a symbol value but not all of our ABI's are able to supply a
377 /// sufficiently sized addend in a single relocation.
378 ///
379 /// The O32 ABI for example, uses REL relocations which store the addend in the
380 /// section data. All the relocations with AHL components affect 16-bit fields
381 /// so the addend for a single relocation is limited to 16-bit. This ABI
382 /// resolves the limitation by linking relocations (e.g. R_MIPS_HI16 and
383 /// R_MIPS_LO16) and distributing the addend between the linked relocations. The
384 /// ABI mandates that such relocations must be next to each other in a
385 /// particular order (e.g. R_MIPS_HI16 must be immediately followed by a
386 /// matching R_MIPS_LO16) but the rule is less strict in practice.
387 ///
388 /// The de facto standard is lenient in the following ways:
389 /// - 'Immediately following' does not refer to the next relocation entry but
390 ///   the next matching relocation.
391 /// - There may be multiple high parts relocations for one low part relocation.
392 /// - There may be multiple low part relocations for one high part relocation.
393 /// - The AHL addend in each part does not have to be exactly equal as long as
394 ///   the difference does not affect the carry bit from bit 15 into 16. This is
395 ///   to allow, for example, the use of %lo(foo) and %lo(foo+4) when loading
396 ///   both halves of a long long.
397 ///
398 /// See getMatchingLoType() for a description of which high part relocations
399 /// match which low part relocations. One particular thing to note is that
400 /// R_MIPS_GOT16 and similar only have AHL addends if they refer to local
401 /// symbols.
402 ///
403 /// It should also be noted that this function is not affected by whether
404 /// the symbol was kept or rewritten into a section-relative equivalent. We
405 /// always match using the expressions from the source.
406 void MipsELFObjectWriter::sortRelocs(const MCAssembler &Asm,
407                                      std::vector<ELFRelocationEntry> &Relocs) {
408   if (Relocs.size() < 2)
409     return;
410 
411   // Sort relocations by the address they are applied to.
412   std::sort(Relocs.begin(), Relocs.end(),
413             [](const ELFRelocationEntry &A, const ELFRelocationEntry &B) {
414               return A.Offset < B.Offset;
415             });
416 
417   std::list<MipsRelocationEntry> Sorted;
418   std::list<ELFRelocationEntry> Remainder;
419 
420   DEBUG(dumpRelocs("R: ", Relocs));
421 
422   // Separate the movable relocations (AHL relocations using the high bits) from
423   // the immobile relocations (everything else). This does not preserve high/low
424   // matches that already existed in the input.
425   copy_if_else(Relocs.begin(), Relocs.end(), std::back_inserter(Remainder),
426                std::back_inserter(Sorted), [](const ELFRelocationEntry &Reloc) {
427                  return getMatchingLoType(Reloc) != ELF::R_MIPS_NONE;
428                });
429 
430   for (auto &R : Remainder) {
431     DEBUG(dbgs() << "Matching: " << R << "\n");
432 
433     unsigned MatchingType = getMatchingLoType(R);
434     assert(MatchingType != ELF::R_MIPS_NONE &&
435            "Wrong list for reloc that doesn't need a match");
436 
437     // Find the best matching relocation for the current high part.
438     // See isMatchingReloc for a description of a matching relocation and
439     // compareMatchingRelocs for a description of what 'best' means.
440     auto InsertionPoint =
441         find_best(Sorted.begin(), Sorted.end(),
442                   [&R, &MatchingType](const MipsRelocationEntry &X) {
443                     return isMatchingReloc(X, R, MatchingType);
444                   },
445                   compareMatchingRelocs);
446 
447     // If we matched then insert the high part in front of the match and mark
448     // both relocations as being involved in a match. We only mark the high
449     // part for cosmetic reasons in the debug output.
450     //
451     // If we failed to find a match then the high part is orphaned. This is not
452     // permitted since the relocation cannot be evaluated without knowing the
453     // carry-in. We can sometimes handle this using a matching low part that is
454     // already used in a match but we already cover that case in
455     // isMatchingReloc and compareMatchingRelocs. For the remaining cases we
456     // should insert the high part at the end of the list. This will cause the
457     // linker to fail but the alternative is to cause the linker to bind the
458     // high part to a semi-matching low part and silently calculate the wrong
459     // value. Unfortunately we have no means to warn the user that we did this
460     // so leave it up to the linker to complain about it.
461     if (InsertionPoint != Sorted.end())
462       InsertionPoint->Matched = true;
463     Sorted.insert(InsertionPoint, R)->Matched = true;
464   }
465 
466   DEBUG(dumpRelocs("S: ", Sorted));
467 
468   assert(Relocs.size() == Sorted.size() && "Some relocs were not consumed");
469 
470   // Overwrite the original vector with the sorted elements. The caller expects
471   // them in reverse order.
472   unsigned CopyTo = 0;
473   for (const auto &R : reverse(Sorted))
474     Relocs[CopyTo++] = R.R;
475 }
476 
477 bool MipsELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
478                                                   unsigned Type) const {
479   // This must be a compound relocation from the N64 ABI.
480   // FIXME: Return false iff all sub-relocations return false.
481   if (!isUInt<8>(Type))
482     return true;
483 
484   switch (Type) {
485   default:
486     errs() << Type << "\n";
487     llvm_unreachable("Unexpected relocation");
488     return true;
489 
490   // This relocation doesn't affect the section data.
491   case ELF::R_MIPS_NONE:
492     return false;
493 
494   // On REL ABI's (e.g. O32), these relocations form pairs. The pairing is done
495   // by the static linker by matching the symbol and offset.
496   // We only see one relocation at a time but it's still safe to relocate with
497   // the section so long as both relocations make the same decision.
498   //
499   // Some older linkers may require the symbol for particular cases. Such cases
500   // are not supported yet but can be added as required.
501   case ELF::R_MIPS_GOT16:
502   case ELF::R_MIPS16_GOT16:
503   case ELF::R_MICROMIPS_GOT16:
504   case ELF::R_MIPS_HI16:
505   case ELF::R_MIPS16_HI16:
506   case ELF::R_MICROMIPS_HI16:
507   case ELF::R_MIPS_LO16:
508   case ELF::R_MIPS16_LO16:
509   case ELF::R_MICROMIPS_LO16:
510     return false;
511 
512   case ELF::R_MIPS_16:
513   case ELF::R_MIPS_32:
514     if (cast<MCSymbolELF>(Sym).getOther() & ELF::STO_MIPS_MICROMIPS)
515       return true;
516     // fallthrough
517   case ELF::R_MIPS_26:
518   case ELF::R_MIPS_64:
519   case ELF::R_MIPS_GPREL16:
520   case ELF::R_MIPS_GPREL32:
521   case ELF::R_MIPS_PC16:
522     return false;
523 
524   // FIXME: Many of these relocations should probably return false but this
525   //        hasn't been confirmed to be safe yet.
526   case ELF::R_MIPS_REL32:
527   case ELF::R_MIPS_LITERAL:
528   case ELF::R_MIPS_CALL16:
529   case ELF::R_MIPS_SHIFT5:
530   case ELF::R_MIPS_SHIFT6:
531   case ELF::R_MIPS_GOT_DISP:
532   case ELF::R_MIPS_GOT_PAGE:
533   case ELF::R_MIPS_GOT_OFST:
534   case ELF::R_MIPS_GOT_HI16:
535   case ELF::R_MIPS_GOT_LO16:
536   case ELF::R_MIPS_SUB:
537   case ELF::R_MIPS_INSERT_A:
538   case ELF::R_MIPS_INSERT_B:
539   case ELF::R_MIPS_DELETE:
540   case ELF::R_MIPS_HIGHER:
541   case ELF::R_MIPS_HIGHEST:
542   case ELF::R_MIPS_CALL_HI16:
543   case ELF::R_MIPS_CALL_LO16:
544   case ELF::R_MIPS_SCN_DISP:
545   case ELF::R_MIPS_REL16:
546   case ELF::R_MIPS_ADD_IMMEDIATE:
547   case ELF::R_MIPS_PJUMP:
548   case ELF::R_MIPS_RELGOT:
549   case ELF::R_MIPS_JALR:
550   case ELF::R_MIPS_TLS_DTPMOD32:
551   case ELF::R_MIPS_TLS_DTPREL32:
552   case ELF::R_MIPS_TLS_DTPMOD64:
553   case ELF::R_MIPS_TLS_DTPREL64:
554   case ELF::R_MIPS_TLS_GD:
555   case ELF::R_MIPS_TLS_LDM:
556   case ELF::R_MIPS_TLS_DTPREL_HI16:
557   case ELF::R_MIPS_TLS_DTPREL_LO16:
558   case ELF::R_MIPS_TLS_GOTTPREL:
559   case ELF::R_MIPS_TLS_TPREL32:
560   case ELF::R_MIPS_TLS_TPREL64:
561   case ELF::R_MIPS_TLS_TPREL_HI16:
562   case ELF::R_MIPS_TLS_TPREL_LO16:
563   case ELF::R_MIPS_GLOB_DAT:
564   case ELF::R_MIPS_PC21_S2:
565   case ELF::R_MIPS_PC26_S2:
566   case ELF::R_MIPS_PC18_S3:
567   case ELF::R_MIPS_PC19_S2:
568   case ELF::R_MIPS_PCHI16:
569   case ELF::R_MIPS_PCLO16:
570   case ELF::R_MIPS_COPY:
571   case ELF::R_MIPS_JUMP_SLOT:
572   case ELF::R_MIPS_NUM:
573   case ELF::R_MIPS_PC32:
574   case ELF::R_MIPS_EH:
575   case ELF::R_MICROMIPS_26_S1:
576   case ELF::R_MICROMIPS_GPREL16:
577   case ELF::R_MICROMIPS_LITERAL:
578   case ELF::R_MICROMIPS_PC7_S1:
579   case ELF::R_MICROMIPS_PC10_S1:
580   case ELF::R_MICROMIPS_PC16_S1:
581   case ELF::R_MICROMIPS_CALL16:
582   case ELF::R_MICROMIPS_GOT_DISP:
583   case ELF::R_MICROMIPS_GOT_PAGE:
584   case ELF::R_MICROMIPS_GOT_OFST:
585   case ELF::R_MICROMIPS_GOT_HI16:
586   case ELF::R_MICROMIPS_GOT_LO16:
587   case ELF::R_MICROMIPS_SUB:
588   case ELF::R_MICROMIPS_HIGHER:
589   case ELF::R_MICROMIPS_HIGHEST:
590   case ELF::R_MICROMIPS_CALL_HI16:
591   case ELF::R_MICROMIPS_CALL_LO16:
592   case ELF::R_MICROMIPS_SCN_DISP:
593   case ELF::R_MICROMIPS_JALR:
594   case ELF::R_MICROMIPS_HI0_LO16:
595   case ELF::R_MICROMIPS_TLS_GD:
596   case ELF::R_MICROMIPS_TLS_LDM:
597   case ELF::R_MICROMIPS_TLS_DTPREL_HI16:
598   case ELF::R_MICROMIPS_TLS_DTPREL_LO16:
599   case ELF::R_MICROMIPS_TLS_GOTTPREL:
600   case ELF::R_MICROMIPS_TLS_TPREL_HI16:
601   case ELF::R_MICROMIPS_TLS_TPREL_LO16:
602   case ELF::R_MICROMIPS_GPREL7_S2:
603   case ELF::R_MICROMIPS_PC23_S2:
604   case ELF::R_MICROMIPS_PC21_S2:
605   case ELF::R_MICROMIPS_PC26_S1:
606   case ELF::R_MICROMIPS_PC18_S3:
607   case ELF::R_MICROMIPS_PC19_S2:
608     return true;
609 
610   // FIXME: Many of these should probably return false but MIPS16 isn't
611   //        supported by the integrated assembler.
612   case ELF::R_MIPS16_26:
613   case ELF::R_MIPS16_GPREL:
614   case ELF::R_MIPS16_CALL16:
615   case ELF::R_MIPS16_TLS_GD:
616   case ELF::R_MIPS16_TLS_LDM:
617   case ELF::R_MIPS16_TLS_DTPREL_HI16:
618   case ELF::R_MIPS16_TLS_DTPREL_LO16:
619   case ELF::R_MIPS16_TLS_GOTTPREL:
620   case ELF::R_MIPS16_TLS_TPREL_HI16:
621   case ELF::R_MIPS16_TLS_TPREL_LO16:
622     llvm_unreachable("Unsupported MIPS16 relocation");
623     return true;
624 
625   }
626 }
627 
628 MCObjectWriter *llvm::createMipsELFObjectWriter(raw_pwrite_stream &OS,
629                                                 uint8_t OSABI,
630                                                 bool IsLittleEndian,
631                                                 bool Is64Bit) {
632   MCELFObjectTargetWriter *MOTW =
633       new MipsELFObjectWriter(Is64Bit, OSABI, Is64Bit, IsLittleEndian);
634   return createELFObjectWriter(MOTW, OS, IsLittleEndian);
635 }
636