forked from OSchip/llvm-project
				
			
		
			
				
	
	
		
			671 lines
		
	
	
		
			24 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			671 lines
		
	
	
		
			24 KiB
		
	
	
	
		
			C++
		
	
	
	
//===-- MipsELFObjectWriter.cpp - Mips ELF Writer -------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "MCTargetDesc/MipsFixupKinds.h"
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#include "MCTargetDesc/MipsMCTargetDesc.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/BinaryFormat/ELF.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCELFObjectWriter.h"
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#include "llvm/MC/MCFixup.h"
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#include "llvm/MC/MCObjectWriter.h"
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#include "llvm/MC/MCSymbolELF.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/MathExtras.h"
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#include "llvm/Support/raw_ostream.h"
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#include <algorithm>
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#include <cassert>
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#include <cstdint>
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#include <iterator>
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#include <list>
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#include <utility>
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#define DEBUG_TYPE "mips-elf-object-writer"
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using namespace llvm;
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namespace {
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/// Holds additional information needed by the relocation ordering algorithm.
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struct MipsRelocationEntry {
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  const ELFRelocationEntry R; ///< The relocation.
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  bool Matched = false;       ///< Is this relocation part of a match.
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  MipsRelocationEntry(const ELFRelocationEntry &R) : R(R) {}
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  void print(raw_ostream &Out) const {
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    R.print(Out);
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    Out << ", Matched=" << Matched;
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  }
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};
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#ifndef NDEBUG
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raw_ostream &operator<<(raw_ostream &OS, const MipsRelocationEntry &RHS) {
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  RHS.print(OS);
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  return OS;
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}
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#endif
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class MipsELFObjectWriter : public MCELFObjectTargetWriter {
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public:
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  MipsELFObjectWriter(uint8_t OSABI, bool HasRelocationAddend, bool Is64);
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  ~MipsELFObjectWriter() override = default;
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  unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
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                        const MCFixup &Fixup, bool IsPCRel) const override;
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  bool needsRelocateWithSymbol(const MCSymbol &Sym,
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                               unsigned Type) const override;
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  void sortRelocs(const MCAssembler &Asm,
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                  std::vector<ELFRelocationEntry> &Relocs) override;
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};
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/// The possible results of the Predicate function used by find_best.
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enum FindBestPredicateResult {
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  FindBest_NoMatch = 0,  ///< The current element is not a match.
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  FindBest_Match,        ///< The current element is a match but better ones are
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                         ///  possible.
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  FindBest_PerfectMatch, ///< The current element is an unbeatable match.
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};
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} // end anonymous namespace
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/// Copy elements in the range [First, Last) to d1 when the predicate is true or
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/// d2 when the predicate is false. This is essentially both std::copy_if and
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/// std::remove_copy_if combined into a single pass.
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template <class InputIt, class OutputIt1, class OutputIt2, class UnaryPredicate>
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static std::pair<OutputIt1, OutputIt2> copy_if_else(InputIt First, InputIt Last,
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                                                    OutputIt1 d1, OutputIt2 d2,
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                                                    UnaryPredicate Predicate) {
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  for (InputIt I = First; I != Last; ++I) {
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    if (Predicate(*I)) {
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      *d1 = *I;
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      d1++;
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    } else {
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      *d2 = *I;
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      d2++;
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    }
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  }
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  return std::make_pair(d1, d2);
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}
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/// Find the best match in the range [First, Last).
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///
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/// An element matches when Predicate(X) returns FindBest_Match or
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/// FindBest_PerfectMatch. A value of FindBest_PerfectMatch also terminates
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/// the search. BetterThan(A, B) is a comparator that returns true when A is a
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/// better match than B. The return value is the position of the best match.
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///
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/// This is similar to std::find_if but finds the best of multiple possible
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/// matches.
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template <class InputIt, class UnaryPredicate, class Comparator>
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static InputIt find_best(InputIt First, InputIt Last, UnaryPredicate Predicate,
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                         Comparator BetterThan) {
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  InputIt Best = Last;
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  for (InputIt I = First; I != Last; ++I) {
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    unsigned Matched = Predicate(*I);
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    if (Matched != FindBest_NoMatch) {
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      LLVM_DEBUG(dbgs() << std::distance(First, I) << " is a match (";
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                 I->print(dbgs()); dbgs() << ")\n");
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      if (Best == Last || BetterThan(*I, *Best)) {
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        LLVM_DEBUG(dbgs() << ".. and it beats the last one\n");
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        Best = I;
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      }
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    }
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    if (Matched == FindBest_PerfectMatch) {
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      LLVM_DEBUG(dbgs() << ".. and it is unbeatable\n");
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      break;
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    }
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  }
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  return Best;
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}
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/// Determine the low relocation that matches the given relocation.
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/// If the relocation does not need a low relocation then the return value
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/// is ELF::R_MIPS_NONE.
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///
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/// The relocations that need a matching low part are
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/// R_(MIPS|MICROMIPS|MIPS16)_HI16 for all symbols and
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/// R_(MIPS|MICROMIPS|MIPS16)_GOT16 for local symbols only.
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static unsigned getMatchingLoType(const ELFRelocationEntry &Reloc) {
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  unsigned Type = Reloc.Type;
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  if (Type == ELF::R_MIPS_HI16)
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    return ELF::R_MIPS_LO16;
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  if (Type == ELF::R_MICROMIPS_HI16)
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    return ELF::R_MICROMIPS_LO16;
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  if (Type == ELF::R_MIPS16_HI16)
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    return ELF::R_MIPS16_LO16;
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  if (Reloc.OriginalSymbol &&
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      Reloc.OriginalSymbol->getBinding() != ELF::STB_LOCAL)
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    return ELF::R_MIPS_NONE;
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  if (Type == ELF::R_MIPS_GOT16)
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    return ELF::R_MIPS_LO16;
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  if (Type == ELF::R_MICROMIPS_GOT16)
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    return ELF::R_MICROMIPS_LO16;
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  if (Type == ELF::R_MIPS16_GOT16)
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    return ELF::R_MIPS16_LO16;
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  return ELF::R_MIPS_NONE;
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}
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/// Determine whether a relocation (X) matches the one given in R.
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///
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/// A relocation matches if:
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/// - It's type matches that of a corresponding low part. This is provided in
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///   MatchingType for efficiency.
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/// - It's based on the same symbol.
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/// - It's offset of greater or equal to that of the one given in R.
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///   It should be noted that this rule assumes the programmer does not use
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///   offsets that exceed the alignment of the symbol. The carry-bit will be
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///   incorrect if this is not true.
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///
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/// A matching relocation is unbeatable if:
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/// - It is not already involved in a match.
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/// - It's offset is exactly that of the one given in R.
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static FindBestPredicateResult isMatchingReloc(const MipsRelocationEntry &X,
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                                               const ELFRelocationEntry &R,
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                                               unsigned MatchingType) {
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  if (X.R.Type == MatchingType && X.R.OriginalSymbol == R.OriginalSymbol) {
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    if (!X.Matched &&
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        X.R.OriginalAddend == R.OriginalAddend)
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      return FindBest_PerfectMatch;
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    else if (X.R.OriginalAddend >= R.OriginalAddend)
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      return FindBest_Match;
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  }
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  return FindBest_NoMatch;
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}
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/// Determine whether Candidate or PreviousBest is the better match.
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/// The return value is true if Candidate is the better match.
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///
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/// A matching relocation is a better match if:
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/// - It has a smaller addend.
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/// - It is not already involved in a match.
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static bool compareMatchingRelocs(const MipsRelocationEntry &Candidate,
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                                  const MipsRelocationEntry &PreviousBest) {
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  if (Candidate.R.OriginalAddend != PreviousBest.R.OriginalAddend)
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    return Candidate.R.OriginalAddend < PreviousBest.R.OriginalAddend;
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  return PreviousBest.Matched && !Candidate.Matched;
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}
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#ifndef NDEBUG
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/// Print all the relocations.
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template <class Container>
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static void dumpRelocs(const char *Prefix, const Container &Relocs) {
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  for (const auto &R : Relocs)
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    dbgs() << Prefix << R << "\n";
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}
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#endif
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MipsELFObjectWriter::MipsELFObjectWriter(uint8_t OSABI,
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                                         bool HasRelocationAddend, bool Is64)
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    : MCELFObjectTargetWriter(Is64, OSABI, ELF::EM_MIPS, HasRelocationAddend) {}
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unsigned MipsELFObjectWriter::getRelocType(MCContext &Ctx,
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                                           const MCValue &Target,
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                                           const MCFixup &Fixup,
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                                           bool IsPCRel) const {
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  // Determine the type of the relocation.
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  unsigned Kind = Fixup.getTargetKind();
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  switch (Kind) {
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  case FK_NONE:
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    return ELF::R_MIPS_NONE;
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  case FK_Data_1:
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    Ctx.reportError(Fixup.getLoc(),
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                    "MIPS does not support one byte relocations");
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    return ELF::R_MIPS_NONE;
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  case Mips::fixup_Mips_16:
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  case FK_Data_2:
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    return IsPCRel ? ELF::R_MIPS_PC16 : ELF::R_MIPS_16;
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  case Mips::fixup_Mips_32:
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  case FK_Data_4:
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    return IsPCRel ? ELF::R_MIPS_PC32 : ELF::R_MIPS_32;
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  case Mips::fixup_Mips_64:
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  case FK_Data_8:
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    return IsPCRel
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               ? setRTypes(ELF::R_MIPS_PC32, ELF::R_MIPS_64, ELF::R_MIPS_NONE)
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               : (unsigned)ELF::R_MIPS_64;
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  }
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  if (IsPCRel) {
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    switch (Kind) {
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    case Mips::fixup_Mips_Branch_PCRel:
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    case Mips::fixup_Mips_PC16:
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      return ELF::R_MIPS_PC16;
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    case Mips::fixup_MICROMIPS_PC7_S1:
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      return ELF::R_MICROMIPS_PC7_S1;
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    case Mips::fixup_MICROMIPS_PC10_S1:
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      return ELF::R_MICROMIPS_PC10_S1;
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    case Mips::fixup_MICROMIPS_PC16_S1:
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      return ELF::R_MICROMIPS_PC16_S1;
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    case Mips::fixup_MICROMIPS_PC26_S1:
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      return ELF::R_MICROMIPS_PC26_S1;
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    case Mips::fixup_MICROMIPS_PC19_S2:
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      return ELF::R_MICROMIPS_PC19_S2;
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    case Mips::fixup_MICROMIPS_PC18_S3:
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      return ELF::R_MICROMIPS_PC18_S3;
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    case Mips::fixup_MICROMIPS_PC21_S1:
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      return ELF::R_MICROMIPS_PC21_S1;
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    case Mips::fixup_MIPS_PC19_S2:
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      return ELF::R_MIPS_PC19_S2;
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    case Mips::fixup_MIPS_PC18_S3:
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      return ELF::R_MIPS_PC18_S3;
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    case Mips::fixup_MIPS_PC21_S2:
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      return ELF::R_MIPS_PC21_S2;
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    case Mips::fixup_MIPS_PC26_S2:
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      return ELF::R_MIPS_PC26_S2;
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    case Mips::fixup_MIPS_PCHI16:
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      return ELF::R_MIPS_PCHI16;
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    case Mips::fixup_MIPS_PCLO16:
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      return ELF::R_MIPS_PCLO16;
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    }
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    llvm_unreachable("invalid PC-relative fixup kind!");
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  }
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  switch (Kind) {
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  case FK_DTPRel_4:
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    return ELF::R_MIPS_TLS_DTPREL32;
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  case FK_DTPRel_8:
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    return ELF::R_MIPS_TLS_DTPREL64;
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  case FK_TPRel_4:
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    return ELF::R_MIPS_TLS_TPREL32;
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  case FK_TPRel_8:
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    return ELF::R_MIPS_TLS_TPREL64;
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  case FK_GPRel_4:
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    return setRTypes(ELF::R_MIPS_GPREL32,
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                     is64Bit() ? ELF::R_MIPS_64 : ELF::R_MIPS_NONE,
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                     ELF::R_MIPS_NONE);
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  case Mips::fixup_Mips_GPREL16:
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    return ELF::R_MIPS_GPREL16;
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  case Mips::fixup_Mips_26:
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    return ELF::R_MIPS_26;
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  case Mips::fixup_Mips_CALL16:
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    return ELF::R_MIPS_CALL16;
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  case Mips::fixup_Mips_GOT:
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    return ELF::R_MIPS_GOT16;
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  case Mips::fixup_Mips_HI16:
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    return ELF::R_MIPS_HI16;
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  case Mips::fixup_Mips_LO16:
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    return ELF::R_MIPS_LO16;
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  case Mips::fixup_Mips_TLSGD:
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    return ELF::R_MIPS_TLS_GD;
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  case Mips::fixup_Mips_GOTTPREL:
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    return ELF::R_MIPS_TLS_GOTTPREL;
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  case Mips::fixup_Mips_TPREL_HI:
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    return ELF::R_MIPS_TLS_TPREL_HI16;
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  case Mips::fixup_Mips_TPREL_LO:
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    return ELF::R_MIPS_TLS_TPREL_LO16;
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  case Mips::fixup_Mips_TLSLDM:
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    return ELF::R_MIPS_TLS_LDM;
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  case Mips::fixup_Mips_DTPREL_HI:
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    return ELF::R_MIPS_TLS_DTPREL_HI16;
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  case Mips::fixup_Mips_DTPREL_LO:
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    return ELF::R_MIPS_TLS_DTPREL_LO16;
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  case Mips::fixup_Mips_GOT_PAGE:
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    return ELF::R_MIPS_GOT_PAGE;
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  case Mips::fixup_Mips_GOT_OFST:
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    return ELF::R_MIPS_GOT_OFST;
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  case Mips::fixup_Mips_GOT_DISP:
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    return ELF::R_MIPS_GOT_DISP;
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  case Mips::fixup_Mips_GPOFF_HI:
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    return setRTypes(ELF::R_MIPS_GPREL16, ELF::R_MIPS_SUB, ELF::R_MIPS_HI16);
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  case Mips::fixup_MICROMIPS_GPOFF_HI:
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    return setRTypes(ELF::R_MICROMIPS_GPREL16, ELF::R_MICROMIPS_SUB,
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                     ELF::R_MICROMIPS_HI16);
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  case Mips::fixup_Mips_GPOFF_LO:
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    return setRTypes(ELF::R_MIPS_GPREL16, ELF::R_MIPS_SUB, ELF::R_MIPS_LO16);
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  case Mips::fixup_MICROMIPS_GPOFF_LO:
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    return setRTypes(ELF::R_MICROMIPS_GPREL16, ELF::R_MICROMIPS_SUB,
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                     ELF::R_MICROMIPS_LO16);
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  case Mips::fixup_Mips_HIGHER:
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    return ELF::R_MIPS_HIGHER;
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  case Mips::fixup_Mips_HIGHEST:
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    return ELF::R_MIPS_HIGHEST;
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  case Mips::fixup_Mips_SUB:
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    return ELF::R_MIPS_SUB;
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  case Mips::fixup_Mips_GOT_HI16:
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    return ELF::R_MIPS_GOT_HI16;
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  case Mips::fixup_Mips_GOT_LO16:
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    return ELF::R_MIPS_GOT_LO16;
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  case Mips::fixup_Mips_CALL_HI16:
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    return ELF::R_MIPS_CALL_HI16;
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  case Mips::fixup_Mips_CALL_LO16:
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    return ELF::R_MIPS_CALL_LO16;
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  case Mips::fixup_MICROMIPS_26_S1:
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    return ELF::R_MICROMIPS_26_S1;
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  case Mips::fixup_MICROMIPS_HI16:
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    return ELF::R_MICROMIPS_HI16;
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  case Mips::fixup_MICROMIPS_LO16:
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    return ELF::R_MICROMIPS_LO16;
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  case Mips::fixup_MICROMIPS_GOT16:
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    return ELF::R_MICROMIPS_GOT16;
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  case Mips::fixup_MICROMIPS_CALL16:
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    return ELF::R_MICROMIPS_CALL16;
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  case Mips::fixup_MICROMIPS_GOT_DISP:
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    return ELF::R_MICROMIPS_GOT_DISP;
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  case Mips::fixup_MICROMIPS_GOT_PAGE:
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    return ELF::R_MICROMIPS_GOT_PAGE;
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  case Mips::fixup_MICROMIPS_GOT_OFST:
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    return ELF::R_MICROMIPS_GOT_OFST;
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  case Mips::fixup_MICROMIPS_TLS_GD:
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    return ELF::R_MICROMIPS_TLS_GD;
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  case Mips::fixup_MICROMIPS_TLS_LDM:
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    return ELF::R_MICROMIPS_TLS_LDM;
 | 
						|
  case Mips::fixup_MICROMIPS_TLS_DTPREL_HI16:
 | 
						|
    return ELF::R_MICROMIPS_TLS_DTPREL_HI16;
 | 
						|
  case Mips::fixup_MICROMIPS_TLS_DTPREL_LO16:
 | 
						|
    return ELF::R_MICROMIPS_TLS_DTPREL_LO16;
 | 
						|
  case Mips::fixup_MICROMIPS_GOTTPREL:
 | 
						|
    return ELF::R_MICROMIPS_TLS_GOTTPREL;
 | 
						|
  case Mips::fixup_MICROMIPS_TLS_TPREL_HI16:
 | 
						|
    return ELF::R_MICROMIPS_TLS_TPREL_HI16;
 | 
						|
  case Mips::fixup_MICROMIPS_TLS_TPREL_LO16:
 | 
						|
    return ELF::R_MICROMIPS_TLS_TPREL_LO16;
 | 
						|
  case Mips::fixup_MICROMIPS_SUB:
 | 
						|
    return ELF::R_MICROMIPS_SUB;
 | 
						|
  case Mips::fixup_MICROMIPS_HIGHER:
 | 
						|
    return ELF::R_MICROMIPS_HIGHER;
 | 
						|
  case Mips::fixup_MICROMIPS_HIGHEST:
 | 
						|
    return ELF::R_MICROMIPS_HIGHEST;
 | 
						|
  case Mips::fixup_Mips_JALR:
 | 
						|
    return ELF::R_MIPS_JALR;
 | 
						|
  case Mips::fixup_MICROMIPS_JALR:
 | 
						|
    return ELF::R_MICROMIPS_JALR;
 | 
						|
  }
 | 
						|
 | 
						|
  llvm_unreachable("invalid fixup kind!");
 | 
						|
}
 | 
						|
 | 
						|
/// Sort relocation table entries by offset except where another order is
 | 
						|
/// required by the MIPS ABI.
 | 
						|
///
 | 
						|
/// MIPS has a few relocations that have an AHL component in the expression used
 | 
						|
/// to evaluate them. This AHL component is an addend with the same number of
 | 
						|
/// bits as a symbol value but not all of our ABI's are able to supply a
 | 
						|
/// sufficiently sized addend in a single relocation.
 | 
						|
///
 | 
						|
/// The O32 ABI for example, uses REL relocations which store the addend in the
 | 
						|
/// section data. All the relocations with AHL components affect 16-bit fields
 | 
						|
/// so the addend for a single relocation is limited to 16-bit. This ABI
 | 
						|
/// resolves the limitation by linking relocations (e.g. R_MIPS_HI16 and
 | 
						|
/// R_MIPS_LO16) and distributing the addend between the linked relocations. The
 | 
						|
/// ABI mandates that such relocations must be next to each other in a
 | 
						|
/// particular order (e.g. R_MIPS_HI16 must be immediately followed by a
 | 
						|
/// matching R_MIPS_LO16) but the rule is less strict in practice.
 | 
						|
///
 | 
						|
/// The de facto standard is lenient in the following ways:
 | 
						|
/// - 'Immediately following' does not refer to the next relocation entry but
 | 
						|
///   the next matching relocation.
 | 
						|
/// - There may be multiple high parts relocations for one low part relocation.
 | 
						|
/// - There may be multiple low part relocations for one high part relocation.
 | 
						|
/// - The AHL addend in each part does not have to be exactly equal as long as
 | 
						|
///   the difference does not affect the carry bit from bit 15 into 16. This is
 | 
						|
///   to allow, for example, the use of %lo(foo) and %lo(foo+4) when loading
 | 
						|
///   both halves of a long long.
 | 
						|
///
 | 
						|
/// See getMatchingLoType() for a description of which high part relocations
 | 
						|
/// match which low part relocations. One particular thing to note is that
 | 
						|
/// R_MIPS_GOT16 and similar only have AHL addends if they refer to local
 | 
						|
/// symbols.
 | 
						|
///
 | 
						|
/// It should also be noted that this function is not affected by whether
 | 
						|
/// the symbol was kept or rewritten into a section-relative equivalent. We
 | 
						|
/// always match using the expressions from the source.
 | 
						|
void MipsELFObjectWriter::sortRelocs(const MCAssembler &Asm,
 | 
						|
                                     std::vector<ELFRelocationEntry> &Relocs) {
 | 
						|
  // We do not need to sort the relocation table for RELA relocations which
 | 
						|
  // N32/N64 uses as the relocation addend contains the value we require,
 | 
						|
  // rather than it being split across a pair of relocations.
 | 
						|
  if (hasRelocationAddend())
 | 
						|
    return;
 | 
						|
 | 
						|
  if (Relocs.size() < 2)
 | 
						|
    return;
 | 
						|
 | 
						|
  // Sort relocations by the address they are applied to.
 | 
						|
  llvm::sort(Relocs,
 | 
						|
             [](const ELFRelocationEntry &A, const ELFRelocationEntry &B) {
 | 
						|
               return A.Offset < B.Offset;
 | 
						|
             });
 | 
						|
 | 
						|
  std::list<MipsRelocationEntry> Sorted;
 | 
						|
  std::list<ELFRelocationEntry> Remainder;
 | 
						|
 | 
						|
  LLVM_DEBUG(dumpRelocs("R: ", Relocs));
 | 
						|
 | 
						|
  // Separate the movable relocations (AHL relocations using the high bits) from
 | 
						|
  // the immobile relocations (everything else). This does not preserve high/low
 | 
						|
  // matches that already existed in the input.
 | 
						|
  copy_if_else(Relocs.begin(), Relocs.end(), std::back_inserter(Remainder),
 | 
						|
               std::back_inserter(Sorted), [](const ELFRelocationEntry &Reloc) {
 | 
						|
                 return getMatchingLoType(Reloc) != ELF::R_MIPS_NONE;
 | 
						|
               });
 | 
						|
 | 
						|
  for (auto &R : Remainder) {
 | 
						|
    LLVM_DEBUG(dbgs() << "Matching: " << R << "\n");
 | 
						|
 | 
						|
    unsigned MatchingType = getMatchingLoType(R);
 | 
						|
    assert(MatchingType != ELF::R_MIPS_NONE &&
 | 
						|
           "Wrong list for reloc that doesn't need a match");
 | 
						|
 | 
						|
    // Find the best matching relocation for the current high part.
 | 
						|
    // See isMatchingReloc for a description of a matching relocation and
 | 
						|
    // compareMatchingRelocs for a description of what 'best' means.
 | 
						|
    auto InsertionPoint =
 | 
						|
        find_best(Sorted.begin(), Sorted.end(),
 | 
						|
                  [&R, &MatchingType](const MipsRelocationEntry &X) {
 | 
						|
                    return isMatchingReloc(X, R, MatchingType);
 | 
						|
                  },
 | 
						|
                  compareMatchingRelocs);
 | 
						|
 | 
						|
    // If we matched then insert the high part in front of the match and mark
 | 
						|
    // both relocations as being involved in a match. We only mark the high
 | 
						|
    // part for cosmetic reasons in the debug output.
 | 
						|
    //
 | 
						|
    // If we failed to find a match then the high part is orphaned. This is not
 | 
						|
    // permitted since the relocation cannot be evaluated without knowing the
 | 
						|
    // carry-in. We can sometimes handle this using a matching low part that is
 | 
						|
    // already used in a match but we already cover that case in
 | 
						|
    // isMatchingReloc and compareMatchingRelocs. For the remaining cases we
 | 
						|
    // should insert the high part at the end of the list. This will cause the
 | 
						|
    // linker to fail but the alternative is to cause the linker to bind the
 | 
						|
    // high part to a semi-matching low part and silently calculate the wrong
 | 
						|
    // value. Unfortunately we have no means to warn the user that we did this
 | 
						|
    // so leave it up to the linker to complain about it.
 | 
						|
    if (InsertionPoint != Sorted.end())
 | 
						|
      InsertionPoint->Matched = true;
 | 
						|
    Sorted.insert(InsertionPoint, R)->Matched = true;
 | 
						|
  }
 | 
						|
 | 
						|
  LLVM_DEBUG(dumpRelocs("S: ", Sorted));
 | 
						|
 | 
						|
  assert(Relocs.size() == Sorted.size() && "Some relocs were not consumed");
 | 
						|
 | 
						|
  // Overwrite the original vector with the sorted elements. The caller expects
 | 
						|
  // them in reverse order.
 | 
						|
  unsigned CopyTo = 0;
 | 
						|
  for (const auto &R : reverse(Sorted))
 | 
						|
    Relocs[CopyTo++] = R.R;
 | 
						|
}
 | 
						|
 | 
						|
bool MipsELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
 | 
						|
                                                  unsigned Type) const {
 | 
						|
  // If it's a compound relocation for N64 then we need the relocation if any
 | 
						|
  // sub-relocation needs it.
 | 
						|
  if (!isUInt<8>(Type))
 | 
						|
    return needsRelocateWithSymbol(Sym, Type & 0xff) ||
 | 
						|
           needsRelocateWithSymbol(Sym, (Type >> 8) & 0xff) ||
 | 
						|
           needsRelocateWithSymbol(Sym, (Type >> 16) & 0xff);
 | 
						|
 | 
						|
  switch (Type) {
 | 
						|
  default:
 | 
						|
    errs() << Type << "\n";
 | 
						|
    llvm_unreachable("Unexpected relocation");
 | 
						|
    return true;
 | 
						|
 | 
						|
  // This relocation doesn't affect the section data.
 | 
						|
  case ELF::R_MIPS_NONE:
 | 
						|
    return false;
 | 
						|
 | 
						|
  // On REL ABI's (e.g. O32), these relocations form pairs. The pairing is done
 | 
						|
  // by the static linker by matching the symbol and offset.
 | 
						|
  // We only see one relocation at a time but it's still safe to relocate with
 | 
						|
  // the section so long as both relocations make the same decision.
 | 
						|
  //
 | 
						|
  // Some older linkers may require the symbol for particular cases. Such cases
 | 
						|
  // are not supported yet but can be added as required.
 | 
						|
  case ELF::R_MIPS_GOT16:
 | 
						|
  case ELF::R_MIPS16_GOT16:
 | 
						|
  case ELF::R_MICROMIPS_GOT16:
 | 
						|
  case ELF::R_MIPS_HIGHER:
 | 
						|
  case ELF::R_MIPS_HIGHEST:
 | 
						|
  case ELF::R_MIPS_HI16:
 | 
						|
  case ELF::R_MIPS16_HI16:
 | 
						|
  case ELF::R_MICROMIPS_HI16:
 | 
						|
  case ELF::R_MIPS_LO16:
 | 
						|
  case ELF::R_MIPS16_LO16:
 | 
						|
  case ELF::R_MICROMIPS_LO16:
 | 
						|
    // FIXME: It should be safe to return false for the STO_MIPS_MICROMIPS but
 | 
						|
    //        we neglect to handle the adjustment to the LSB of the addend that
 | 
						|
    //        it causes in applyFixup() and similar.
 | 
						|
    if (cast<MCSymbolELF>(Sym).getOther() & ELF::STO_MIPS_MICROMIPS)
 | 
						|
      return true;
 | 
						|
    return false;
 | 
						|
 | 
						|
  case ELF::R_MIPS_GOT_PAGE:
 | 
						|
  case ELF::R_MICROMIPS_GOT_PAGE:
 | 
						|
  case ELF::R_MIPS_GOT_OFST:
 | 
						|
  case ELF::R_MICROMIPS_GOT_OFST:
 | 
						|
  case ELF::R_MIPS_16:
 | 
						|
  case ELF::R_MIPS_32:
 | 
						|
  case ELF::R_MIPS_GPREL32:
 | 
						|
    if (cast<MCSymbolELF>(Sym).getOther() & ELF::STO_MIPS_MICROMIPS)
 | 
						|
      return true;
 | 
						|
    LLVM_FALLTHROUGH;
 | 
						|
  case ELF::R_MIPS_26:
 | 
						|
  case ELF::R_MIPS_64:
 | 
						|
  case ELF::R_MIPS_GPREL16:
 | 
						|
  case ELF::R_MIPS_PC16:
 | 
						|
  case ELF::R_MIPS_SUB:
 | 
						|
    return false;
 | 
						|
 | 
						|
  // FIXME: Many of these relocations should probably return false but this
 | 
						|
  //        hasn't been confirmed to be safe yet.
 | 
						|
  case ELF::R_MIPS_REL32:
 | 
						|
  case ELF::R_MIPS_LITERAL:
 | 
						|
  case ELF::R_MIPS_CALL16:
 | 
						|
  case ELF::R_MIPS_SHIFT5:
 | 
						|
  case ELF::R_MIPS_SHIFT6:
 | 
						|
  case ELF::R_MIPS_GOT_DISP:
 | 
						|
  case ELF::R_MIPS_GOT_HI16:
 | 
						|
  case ELF::R_MIPS_GOT_LO16:
 | 
						|
  case ELF::R_MIPS_INSERT_A:
 | 
						|
  case ELF::R_MIPS_INSERT_B:
 | 
						|
  case ELF::R_MIPS_DELETE:
 | 
						|
  case ELF::R_MIPS_CALL_HI16:
 | 
						|
  case ELF::R_MIPS_CALL_LO16:
 | 
						|
  case ELF::R_MIPS_SCN_DISP:
 | 
						|
  case ELF::R_MIPS_REL16:
 | 
						|
  case ELF::R_MIPS_ADD_IMMEDIATE:
 | 
						|
  case ELF::R_MIPS_PJUMP:
 | 
						|
  case ELF::R_MIPS_RELGOT:
 | 
						|
  case ELF::R_MIPS_JALR:
 | 
						|
  case ELF::R_MIPS_TLS_DTPMOD32:
 | 
						|
  case ELF::R_MIPS_TLS_DTPREL32:
 | 
						|
  case ELF::R_MIPS_TLS_DTPMOD64:
 | 
						|
  case ELF::R_MIPS_TLS_DTPREL64:
 | 
						|
  case ELF::R_MIPS_TLS_GD:
 | 
						|
  case ELF::R_MIPS_TLS_LDM:
 | 
						|
  case ELF::R_MIPS_TLS_DTPREL_HI16:
 | 
						|
  case ELF::R_MIPS_TLS_DTPREL_LO16:
 | 
						|
  case ELF::R_MIPS_TLS_GOTTPREL:
 | 
						|
  case ELF::R_MIPS_TLS_TPREL32:
 | 
						|
  case ELF::R_MIPS_TLS_TPREL64:
 | 
						|
  case ELF::R_MIPS_TLS_TPREL_HI16:
 | 
						|
  case ELF::R_MIPS_TLS_TPREL_LO16:
 | 
						|
  case ELF::R_MIPS_GLOB_DAT:
 | 
						|
  case ELF::R_MIPS_PC21_S2:
 | 
						|
  case ELF::R_MIPS_PC26_S2:
 | 
						|
  case ELF::R_MIPS_PC18_S3:
 | 
						|
  case ELF::R_MIPS_PC19_S2:
 | 
						|
  case ELF::R_MIPS_PCHI16:
 | 
						|
  case ELF::R_MIPS_PCLO16:
 | 
						|
  case ELF::R_MIPS_COPY:
 | 
						|
  case ELF::R_MIPS_JUMP_SLOT:
 | 
						|
  case ELF::R_MIPS_NUM:
 | 
						|
  case ELF::R_MIPS_PC32:
 | 
						|
  case ELF::R_MIPS_EH:
 | 
						|
  case ELF::R_MICROMIPS_26_S1:
 | 
						|
  case ELF::R_MICROMIPS_GPREL16:
 | 
						|
  case ELF::R_MICROMIPS_LITERAL:
 | 
						|
  case ELF::R_MICROMIPS_PC7_S1:
 | 
						|
  case ELF::R_MICROMIPS_PC10_S1:
 | 
						|
  case ELF::R_MICROMIPS_PC16_S1:
 | 
						|
  case ELF::R_MICROMIPS_CALL16:
 | 
						|
  case ELF::R_MICROMIPS_GOT_DISP:
 | 
						|
  case ELF::R_MICROMIPS_GOT_HI16:
 | 
						|
  case ELF::R_MICROMIPS_GOT_LO16:
 | 
						|
  case ELF::R_MICROMIPS_SUB:
 | 
						|
  case ELF::R_MICROMIPS_HIGHER:
 | 
						|
  case ELF::R_MICROMIPS_HIGHEST:
 | 
						|
  case ELF::R_MICROMIPS_CALL_HI16:
 | 
						|
  case ELF::R_MICROMIPS_CALL_LO16:
 | 
						|
  case ELF::R_MICROMIPS_SCN_DISP:
 | 
						|
  case ELF::R_MICROMIPS_JALR:
 | 
						|
  case ELF::R_MICROMIPS_HI0_LO16:
 | 
						|
  case ELF::R_MICROMIPS_TLS_GD:
 | 
						|
  case ELF::R_MICROMIPS_TLS_LDM:
 | 
						|
  case ELF::R_MICROMIPS_TLS_DTPREL_HI16:
 | 
						|
  case ELF::R_MICROMIPS_TLS_DTPREL_LO16:
 | 
						|
  case ELF::R_MICROMIPS_TLS_GOTTPREL:
 | 
						|
  case ELF::R_MICROMIPS_TLS_TPREL_HI16:
 | 
						|
  case ELF::R_MICROMIPS_TLS_TPREL_LO16:
 | 
						|
  case ELF::R_MICROMIPS_GPREL7_S2:
 | 
						|
  case ELF::R_MICROMIPS_PC23_S2:
 | 
						|
  case ELF::R_MICROMIPS_PC21_S1:
 | 
						|
  case ELF::R_MICROMIPS_PC26_S1:
 | 
						|
  case ELF::R_MICROMIPS_PC18_S3:
 | 
						|
  case ELF::R_MICROMIPS_PC19_S2:
 | 
						|
    return true;
 | 
						|
 | 
						|
  // FIXME: Many of these should probably return false but MIPS16 isn't
 | 
						|
  //        supported by the integrated assembler.
 | 
						|
  case ELF::R_MIPS16_26:
 | 
						|
  case ELF::R_MIPS16_GPREL:
 | 
						|
  case ELF::R_MIPS16_CALL16:
 | 
						|
  case ELF::R_MIPS16_TLS_GD:
 | 
						|
  case ELF::R_MIPS16_TLS_LDM:
 | 
						|
  case ELF::R_MIPS16_TLS_DTPREL_HI16:
 | 
						|
  case ELF::R_MIPS16_TLS_DTPREL_LO16:
 | 
						|
  case ELF::R_MIPS16_TLS_GOTTPREL:
 | 
						|
  case ELF::R_MIPS16_TLS_TPREL_HI16:
 | 
						|
  case ELF::R_MIPS16_TLS_TPREL_LO16:
 | 
						|
    llvm_unreachable("Unsupported MIPS16 relocation");
 | 
						|
    return true;
 | 
						|
  }
 | 
						|
}
 | 
						|
 | 
						|
std::unique_ptr<MCObjectTargetWriter>
 | 
						|
llvm::createMipsELFObjectWriter(const Triple &TT, bool IsN32) {
 | 
						|
  uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS());
 | 
						|
  bool IsN64 = TT.isArch64Bit() && !IsN32;
 | 
						|
  bool HasRelocationAddend = TT.isArch64Bit();
 | 
						|
  return std::make_unique<MipsELFObjectWriter>(OSABI, HasRelocationAddend,
 | 
						|
                                                IsN64);
 | 
						|
}
 |