contrib/llvm/lib/MC/MCELFObjectTargetWriter.cpp

   1 //===-- MCELFObjectTargetWriter.cpp - ELF Target Writer Subclass ----------===//
   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 "llvm/ADT/STLExtras.h"
  11 #include "llvm/MC/MCELFObjectWriter.h"
  12 #include "llvm/MC/MCExpr.h"
  13 #include "llvm/MC/MCValue.h"
  14
  15 using namespace llvm;
  16
  17 MCELFObjectTargetWriter::MCELFObjectTargetWriter(bool Is64Bit_,
  18                                                  uint8_t OSABI_,
  19                                                  uint16_t EMachine_,
  20                                                  bool HasRelocationAddend_,
  21                                                  bool IsN64_)
  22   : OSABI(OSABI_), EMachine(EMachine_),
  23     HasRelocationAddend(HasRelocationAddend_), Is64Bit(Is64Bit_),
  24     IsN64(IsN64_){
  25 }
  26
  27 const MCSymbol *MCELFObjectTargetWriter::ExplicitRelSym(const MCAssembler &Asm,
  28                                                         const MCValue &Target,
  29                                                         const MCFragment &F,
  30                                                         const MCFixup &Fixup,
  31                                                         bool IsPCRel) const {
  32   return NULL;
  33 }
  34
  35 const MCSymbol *MCELFObjectTargetWriter::undefinedExplicitRelSym(const MCValue &Target,
  36                                                                  const MCFixup &Fixup,
  37                                                                  bool IsPCRel) const {
  38   const MCSymbol &Symbol = Target.getSymA()->getSymbol();
  39   return &Symbol.AliasedSymbol();
  40 }
  41
  42 // ELF doesn't require relocations to be in any order. We sort by the r_offset,
  43 // just to match gnu as for easier comparison. The use type and index is an
  44 // arbitrary way of making the sort deterministic.
  45 static int cmpRel(const ELFRelocationEntry *AP, const ELFRelocationEntry *BP) {
  46   const ELFRelocationEntry &A = *AP;
  47   const ELFRelocationEntry &B = *BP;
  48   if (A.r_offset != B.r_offset)
  49     return B.r_offset - A.r_offset;
  50   if (B.Type != A.Type)
  51     return A.Type - B.Type;
  52   if (B.Index != A.Index)
  53     return B.Index - A.Index;
  54   llvm_unreachable("ELFRelocs might be unstable!");
  55 }
  56
  57 void
  58 MCELFObjectTargetWriter::sortRelocs(const MCAssembler &Asm,
  59                                     std::vector<ELFRelocationEntry> &Relocs) {
  60   array_pod_sort(Relocs.begin(), Relocs.end(), cmpRel);
  61 }