lib/Target/PowerPC/PPCMachOWriterInfo.cpp

   1 //===-- PPCMachOWriterInfo.cpp - Mach-O Writer Info for the PowerPC -------===//
   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 Mach-O writer information for the PowerPC backend.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "PPCMachOWriterInfo.h"
  15 #include "PPCRelocations.h"
  16 #include "PPCTargetMachine.h"
  17 #include "llvm/CodeGen/MachORelocation.h"
  18 #include "llvm/Support/OutputBuffer.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20 #include <cstdio>
  21 using namespace llvm;
  22
  23 PPCMachOWriterInfo::PPCMachOWriterInfo(const PPCTargetMachine &TM)
  24   : TargetMachOWriterInfo(TM.getTargetData()->getPointerSizeInBits() == 64 ?
  25                           HDR_CPU_TYPE_POWERPC64 :
  26                           HDR_CPU_TYPE_POWERPC,
  27                           HDR_CPU_SUBTYPE_POWERPC_ALL) {}
  28 PPCMachOWriterInfo::~PPCMachOWriterInfo() {}
  29
  30 /// GetTargetRelocation - For the MachineRelocation MR, convert it to one or
  31 /// more PowerPC MachORelocation(s), add the new relocations to the
  32 /// MachOSection, and rewrite the instruction at the section offset if required
  33 /// by that relocation type.
  34 unsigned PPCMachOWriterInfo::GetTargetRelocation(MachineRelocation &MR,
  35                                                  unsigned FromIdx,
  36                                                  unsigned ToAddr,
  37                                                  unsigned ToIdx,
  38                                                  OutputBuffer &RelocOut,
  39                                                  OutputBuffer &SecOut,
  40                                                  bool Scattered,
  41                                                  bool isExtern) const {
  42   unsigned NumRelocs = 0;
  43   uint64_t Addr = 0;
  44
  45   // Get the address of whatever it is we're relocating, if possible.
  46   if (!isExtern)
  47     Addr = (uintptr_t)MR.getResultPointer() + ToAddr;
  48
  49   switch ((PPC::RelocationType)MR.getRelocationType()) {
  50   default: llvm_unreachable("Unknown PPC relocation type!");
  51   case PPC::reloc_absolute_low_ix:
  52     llvm_unreachable("Unhandled PPC relocation type!");
  53     break;
  54   case PPC::reloc_vanilla:
  55     {
  56       // FIXME: need to handle 64 bit vanilla relocs
  57       MachORelocation VANILLA(MR.getMachineCodeOffset(), ToIdx,
  58                               false, 2, isExtern,
  59                               PPC_RELOC_VANILLA,
  60                               Scattered, (intptr_t)MR.getResultPointer());
  61       ++NumRelocs;
  62
  63       if (Scattered) {
  64         RelocOut.outword(VANILLA.getPackedFields());
  65         RelocOut.outword(VANILLA.getAddress());
  66       } else {
  67         RelocOut.outword(VANILLA.getAddress());
  68         RelocOut.outword(VANILLA.getPackedFields());
  69       }
  70
  71       intptr_t SymbolOffset;
  72
  73       if (Scattered)
  74         SymbolOffset = Addr + MR.getConstantVal();
  75       else
  76         SymbolOffset = Addr;
  77
  78       printf("vanilla fixup: sec_%x[%x] = %x\n", FromIdx,
  79              unsigned(MR.getMachineCodeOffset()),
  80              unsigned(SymbolOffset));
  81       SecOut.fixword(SymbolOffset, MR.getMachineCodeOffset());
  82     }
  83     break;
  84   case PPC::reloc_pcrel_bx:
  85     {
  86       // FIXME: Presumably someday we will need to branch to other, non-extern
  87       // functions too.  Need to figure out some way to distinguish between
  88       // target is BB and target is function.
  89       if (isExtern) {
  90         MachORelocation BR24(MR.getMachineCodeOffset(), ToIdx, true, 2,
  91                              isExtern, PPC_RELOC_BR24, Scattered,
  92                              (intptr_t)MR.getMachineCodeOffset());
  93         RelocOut.outword(BR24.getAddress());
  94         RelocOut.outword(BR24.getPackedFields());
  95         ++NumRelocs;
  96       }
  97
  98       Addr -= MR.getMachineCodeOffset();
  99       Addr >>= 2;
 100       Addr &= 0xFFFFFF;
 101       Addr <<= 2;
 102       Addr |= (SecOut[MR.getMachineCodeOffset()] << 24);
 103       Addr |= (SecOut[MR.getMachineCodeOffset()+3] & 0x3);
 104       SecOut.fixword(Addr, MR.getMachineCodeOffset());
 105       break;
 106     }
 107   case PPC::reloc_pcrel_bcx:
 108     {
 109       Addr -= MR.getMachineCodeOffset();
 110       Addr &= 0xFFFC;
 111
 112       SecOut.fixhalf(Addr, MR.getMachineCodeOffset() + 2);
 113       break;
 114     }
 115   case PPC::reloc_absolute_high:
 116     {
 117       MachORelocation HA16(MR.getMachineCodeOffset(), ToIdx, false, 2,
 118                            isExtern, PPC_RELOC_HA16);
 119       MachORelocation PAIR(Addr & 0xFFFF, 0xFFFFFF, false, 2, isExtern,
 120                            PPC_RELOC_PAIR);
 121       NumRelocs = 2;
 122
 123       RelocOut.outword(HA16.getRawAddress());
 124       RelocOut.outword(HA16.getPackedFields());
 125       RelocOut.outword(PAIR.getRawAddress());
 126       RelocOut.outword(PAIR.getPackedFields());
 127
 128       Addr += 0x8000;
 129
 130       SecOut.fixhalf(Addr >> 16, MR.getMachineCodeOffset() + 2);
 131       break;
 132     }
 133   case PPC::reloc_absolute_low:
 134     {
 135       MachORelocation LO16(MR.getMachineCodeOffset(), ToIdx, false, 2,
 136                            isExtern, PPC_RELOC_LO16);
 137       MachORelocation PAIR(Addr >> 16, 0xFFFFFF, false, 2, isExtern,
 138                            PPC_RELOC_PAIR);
 139       NumRelocs = 2;
 140
 141       RelocOut.outword(LO16.getRawAddress());
 142       RelocOut.outword(LO16.getPackedFields());
 143       RelocOut.outword(PAIR.getRawAddress());
 144       RelocOut.outword(PAIR.getPackedFields());
 145
 146       SecOut.fixhalf(Addr, MR.getMachineCodeOffset() + 2);
 147       break;
 148     }
 149   }
 150
 151   return NumRelocs;
 152 }