lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOX86_64.h

   1 //===-- RuntimeDyldMachOX86_64.h ---- MachO/X86_64 specific code. -*- C++ -*-=//
   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 #ifndef LLVM_RUNTIMEDYLDMACHOX86_64_H
  11 #define LLVM_RUNTIMEDYLDMACHOX86_64_H
  12
  13 #include "../RuntimeDyldMachO.h"
  14
  15 #define DEBUG_TYPE "dyld"
  16
  17 namespace llvm {
  18
  19 class RuntimeDyldMachOX86_64
  20     : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOX86_64> {
  21 public:
  22   RuntimeDyldMachOX86_64(RTDyldMemoryManager *MM)
  23       : RuntimeDyldMachOCRTPBase(MM) {}
  24
  25   unsigned getMaxStubSize() override { return 8; }
  26
  27   unsigned getStubAlignment() override { return 1; }
  28
  29   relocation_iterator
  30   processRelocationRef(unsigned SectionID, relocation_iterator RelI,
  31                        ObjectImage &ObjImg, ObjSectionToIDMap &ObjSectionToID,
  32                        const SymbolTableMap &Symbols, StubMap &Stubs) override {
  33     const MachOObjectFile &Obj =
  34         static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
  35     MachO::any_relocation_info RelInfo =
  36         Obj.getRelocation(RelI->getRawDataRefImpl());
  37
  38     assert(!Obj.isRelocationScattered(RelInfo) &&
  39            "Scattered relocations not supported on X86_64");
  40
  41     RelocationEntry RE(getBasicRelocationEntry(SectionID, ObjImg, RelI));
  42     RelocationValueRef Value(
  43         getRelocationValueRef(ObjImg, RelI, RE, ObjSectionToID, Symbols));
  44
  45     bool IsExtern = Obj.getPlainRelocationExternal(RelInfo);
  46     if (!IsExtern && RE.IsPCRel)
  47       makeValueAddendPCRel(Value, ObjImg, RelI, 1 << RE.Size);
  48
  49     if (RE.RelType == MachO::X86_64_RELOC_GOT ||
  50         RE.RelType == MachO::X86_64_RELOC_GOT_LOAD)
  51       processGOTRelocation(RE, Value, Stubs);
  52     else {
  53       RE.Addend = Value.Addend;
  54       if (Value.SymbolName)
  55         addRelocationForSymbol(RE, Value.SymbolName);
  56       else
  57         addRelocationForSection(RE, Value.SectionID);
  58     }
  59
  60     return ++RelI;
  61   }
  62
  63   void resolveRelocation(const RelocationEntry &RE, uint64_t Value) {
  64     DEBUG(dumpRelocationToResolve(RE, Value));
  65     const SectionEntry &Section = Sections[RE.SectionID];
  66     uint8_t *LocalAddress = Section.Address + RE.Offset;
  67
  68     // If the relocation is PC-relative, the value to be encoded is the
  69     // pointer difference.
  70     if (RE.IsPCRel) {
  71       // FIXME: It seems this value needs to be adjusted by 4 for an effective
  72       // PC address. Is that expected? Only for branches, perhaps?
  73       uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
  74       Value -= FinalAddress + 4;
  75     }
  76
  77     switch (RE.RelType) {
  78     default:
  79       llvm_unreachable("Invalid relocation type!");
  80     case MachO::X86_64_RELOC_SIGNED_1:
  81     case MachO::X86_64_RELOC_SIGNED_2:
  82     case MachO::X86_64_RELOC_SIGNED_4:
  83     case MachO::X86_64_RELOC_SIGNED:
  84     case MachO::X86_64_RELOC_UNSIGNED:
  85     case MachO::X86_64_RELOC_BRANCH:
  86       writeBytesUnaligned(LocalAddress, Value + RE.Addend, 1 << RE.Size);
  87       break;
  88     case MachO::X86_64_RELOC_GOT_LOAD:
  89     case MachO::X86_64_RELOC_GOT:
  90     case MachO::X86_64_RELOC_SUBTRACTOR:
  91     case MachO::X86_64_RELOC_TLV:
  92       Error("Relocation type not implemented yet!");
  93     }
  94   }
  95
  96   void finalizeSection(ObjectImage &ObjImg, unsigned SectionID,
  97                        const SectionRef &Section) {}
  98
  99 private:
 100   void processGOTRelocation(const RelocationEntry &RE,
 101                             RelocationValueRef &Value, StubMap &Stubs) {
 102     SectionEntry &Section = Sections[RE.SectionID];
 103     assert(RE.IsPCRel);
 104     assert(RE.Size == 2);
 105     Value.Addend -= RE.Addend;
 106     RuntimeDyldMachO::StubMap::const_iterator i = Stubs.find(Value);
 107     uint8_t *Addr;
 108     if (i != Stubs.end()) {
 109       Addr = Section.Address + i->second;
 110     } else {
 111       Stubs[Value] = Section.StubOffset;
 112       uint8_t *GOTEntry = Section.Address + Section.StubOffset;
 113       RelocationEntry GOTRE(RE.SectionID, Section.StubOffset,
 114                             MachO::X86_64_RELOC_UNSIGNED, Value.Addend, false,
 115                             3);
 116       if (Value.SymbolName)
 117         addRelocationForSymbol(GOTRE, Value.SymbolName);
 118       else
 119         addRelocationForSection(GOTRE, Value.SectionID);
 120       Section.StubOffset += 8;
 121       Addr = GOTEntry;
 122     }
 123     RelocationEntry TargetRE(RE.SectionID, RE.Offset,
 124                              MachO::X86_64_RELOC_UNSIGNED, RE.Addend, true, 2);
 125     resolveRelocation(TargetRE, (uint64_t)Addr);
 126   }
 127 };
 128 }
 129
 130 #undef DEBUG_TYPE
 131
 132 #endif // LLVM_RUNTIMEDYLDMACHOX86_64_H