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_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOX86_64_H
  11 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_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
  23   typedef uint64_t TargetPtrT;
  24
  25   RuntimeDyldMachOX86_64(RTDyldMemoryManager *MM)
  26       : RuntimeDyldMachOCRTPBase(MM) {}
  27
  28   unsigned getMaxStubSize() override { return 8; }
  29
  30   unsigned getStubAlignment() override { return 1; }
  31
  32   relocation_iterator
  33   processRelocationRef(unsigned SectionID, relocation_iterator RelI,
  34                        const ObjectFile &BaseObjT,
  35                        ObjSectionToIDMap &ObjSectionToID,
  36                        StubMap &Stubs) override {
  37     const MachOObjectFile &Obj =
  38       static_cast<const MachOObjectFile &>(BaseObjT);
  39     MachO::any_relocation_info RelInfo =
  40         Obj.getRelocation(RelI->getRawDataRefImpl());
  41
  42     assert(!Obj.isRelocationScattered(RelInfo) &&
  43            "Scattered relocations not supported on X86_64");
  44
  45     RelocationEntry RE(getRelocationEntry(SectionID, Obj, RelI));
  46     RE.Addend = memcpyAddend(RE);
  47     RelocationValueRef Value(
  48         getRelocationValueRef(Obj, RelI, RE, ObjSectionToID));
  49
  50     bool IsExtern = Obj.getPlainRelocationExternal(RelInfo);
  51     if (!IsExtern && RE.IsPCRel)
  52       makeValueAddendPCRel(Value, Obj, RelI, 1 << RE.Size);
  53
  54     if (RE.RelType == MachO::X86_64_RELOC_GOT ||
  55         RE.RelType == MachO::X86_64_RELOC_GOT_LOAD)
  56       processGOTRelocation(RE, Value, Stubs);
  57     else {
  58       RE.Addend = Value.Offset;
  59       if (Value.SymbolName)
  60         addRelocationForSymbol(RE, Value.SymbolName);
  61       else
  62         addRelocationForSection(RE, Value.SectionID);
  63     }
  64
  65     return ++RelI;
  66   }
  67
  68   void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {
  69     DEBUG(dumpRelocationToResolve(RE, Value));
  70     const SectionEntry &Section = Sections[RE.SectionID];
  71     uint8_t *LocalAddress = Section.Address + RE.Offset;
  72
  73     // If the relocation is PC-relative, the value to be encoded is the
  74     // pointer difference.
  75     if (RE.IsPCRel) {
  76       // FIXME: It seems this value needs to be adjusted by 4 for an effective
  77       // PC address. Is that expected? Only for branches, perhaps?
  78       uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
  79       Value -= FinalAddress + 4;
  80     }
  81
  82     switch (RE.RelType) {
  83     default:
  84       llvm_unreachable("Invalid relocation type!");
  85     case MachO::X86_64_RELOC_SIGNED_1:
  86     case MachO::X86_64_RELOC_SIGNED_2:
  87     case MachO::X86_64_RELOC_SIGNED_4:
  88     case MachO::X86_64_RELOC_SIGNED:
  89     case MachO::X86_64_RELOC_UNSIGNED:
  90     case MachO::X86_64_RELOC_BRANCH:
  91       writeBytesUnaligned(Value + RE.Addend, LocalAddress, 1 << RE.Size);
  92       break;
  93     case MachO::X86_64_RELOC_GOT_LOAD:
  94     case MachO::X86_64_RELOC_GOT:
  95     case MachO::X86_64_RELOC_SUBTRACTOR:
  96     case MachO::X86_64_RELOC_TLV:
  97       Error("Relocation type not implemented yet!");
  98     }
  99   }
 100
 101   void finalizeSection(const ObjectFile &Obj, unsigned SectionID,
 102                        const SectionRef &Section) {}
 103
 104 private:
 105   void processGOTRelocation(const RelocationEntry &RE,
 106                             RelocationValueRef &Value, StubMap &Stubs) {
 107     SectionEntry &Section = Sections[RE.SectionID];
 108     assert(RE.IsPCRel);
 109     assert(RE.Size == 2);
 110     Value.Offset -= RE.Addend;
 111     RuntimeDyldMachO::StubMap::const_iterator i = Stubs.find(Value);
 112     uint8_t *Addr;
 113     if (i != Stubs.end()) {
 114       Addr = Section.Address + i->second;
 115     } else {
 116       Stubs[Value] = Section.StubOffset;
 117       uint8_t *GOTEntry = Section.Address + Section.StubOffset;
 118       RelocationEntry GOTRE(RE.SectionID, Section.StubOffset,
 119                             MachO::X86_64_RELOC_UNSIGNED, Value.Offset, false,
 120                             3);
 121       if (Value.SymbolName)
 122         addRelocationForSymbol(GOTRE, Value.SymbolName);
 123       else
 124         addRelocationForSection(GOTRE, Value.SectionID);
 125       Section.StubOffset += 8;
 126       Addr = GOTEntry;
 127     }
 128     RelocationEntry TargetRE(RE.SectionID, RE.Offset,
 129                              MachO::X86_64_RELOC_UNSIGNED, RE.Addend, true, 2);
 130     resolveRelocation(TargetRE, (uint64_t)Addr);
 131   }
 132 };
 133 }
 134
 135 #undef DEBUG_TYPE
 136
 137 #endif