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