lib/Target/Mips/MipsELFWriterInfo.cpp

   1 //===-- MipsELFWriterInfo.cpp - ELF Writer Info for the Mips backend --------===//
   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 // This file implements ELF writer information for the Mips backend.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "MipsELFWriterInfo.h"
  15 #include "MipsRelocations.h"
  16 #include "llvm/Function.h"
  17 #include "llvm/Support/ErrorHandling.h"
  18 #include "llvm/Target/TargetData.h"
  19 #include "llvm/Target/TargetMachine.h"
  20 #include "llvm/Support/ELF.h"
  21
  22 using namespace llvm;
  23
  24 //===----------------------------------------------------------------------===//
  25 //  Implementation of the MipsELFWriterInfo class
  26 //===----------------------------------------------------------------------===//
  27
  28 MipsELFWriterInfo::MipsELFWriterInfo(bool is64Bit_, bool isLittleEndian_)
  29   : TargetELFWriterInfo(is64Bit_, isLittleEndian_) {
  30     EMachine = EM_MIPS;
  31   }
  32
  33 MipsELFWriterInfo::~MipsELFWriterInfo() {}
  34
  35 unsigned MipsELFWriterInfo::getRelocationType(unsigned MachineRelTy) const {
  36     switch(MachineRelTy) {
  37     case Mips::reloc_mips_pc16:
  38       return ELF::R_MIPS_GOT16;
  39     case Mips::reloc_mips_hi:
  40       return ELF::R_MIPS_HI16;
  41     case Mips::reloc_mips_lo:
  42       return ELF::R_MIPS_LO16;
  43     case Mips::reloc_mips_26:
  44       return ELF::R_MIPS_26;
  45     default:
  46       llvm_unreachable("unknown Mips machine relocation type");
  47     }
  48 }
  49
  50 long int MipsELFWriterInfo::getDefaultAddendForRelTy(unsigned RelTy,
  51                                                     long int Modifier) const {
  52     switch(RelTy) {
  53     case ELF::R_MIPS_26: return Modifier;
  54     default:
  55       llvm_unreachable("unknown Mips relocation type");
  56     }
  57 }
  58
  59 unsigned MipsELFWriterInfo::getRelocationTySize(unsigned RelTy) const {
  60     switch(RelTy) {
  61     case ELF::R_MIPS_GOT16:
  62     case ELF::R_MIPS_26:
  63         return 32;
  64     default:
  65       llvm_unreachable("unknown Mips relocation type");
  66     }
  67 }
  68
  69 bool MipsELFWriterInfo::isPCRelativeRel(unsigned RelTy) const {
  70     switch(RelTy) {
  71     case ELF::R_MIPS_GOT16:
  72         return true;
  73     case ELF::R_MIPS_26:
  74         return false;
  75     default:
  76       llvm_unreachable("unknown Mips relocation type");
  77     }
  78 }
  79
  80 unsigned MipsELFWriterInfo::getAbsoluteLabelMachineRelTy() const {
  81   return Mips::reloc_mips_26;
  82 }
  83
  84 long int MipsELFWriterInfo::computeRelocation(unsigned SymOffset,
  85                                              unsigned RelOffset,
  86                                              unsigned RelTy) const {
  87
  88   if (RelTy == ELF::R_MIPS_GOT16)
  89     return SymOffset - (RelOffset + 4);
  90
  91   llvm_unreachable("computeRelocation unknown for this relocation type");
  92 }