lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.h

   1 //===-- RuntimeDyldMachO.h - Run-time dynamic linker for MC-JIT ---*- C++ -*-=//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // MachO support for MC-JIT runtime dynamic linker.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDMACHO_H
  14 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDMACHO_H
  15
  16 #include "RuntimeDyldImpl.h"
  17 #include "llvm/Object/MachO.h"
  18 #include "llvm/Support/Format.h"
  19
  20 #define DEBUG_TYPE "dyld"
  21
  22 using namespace llvm;
  23 using namespace llvm::object;
  24
  25 namespace llvm {
  26 class RuntimeDyldMachO : public RuntimeDyldImpl {
  27 protected:
  28   struct SectionOffsetPair {
  29     unsigned SectionID;
  30     uint64_t Offset;
  31   };
  32
  33   struct EHFrameRelatedSections {
  34     EHFrameRelatedSections()
  35         : EHFrameSID(RTDYLD_INVALID_SECTION_ID),
  36           TextSID(RTDYLD_INVALID_SECTION_ID),
  37           ExceptTabSID(RTDYLD_INVALID_SECTION_ID) {}
  38
  39     EHFrameRelatedSections(SID EH, SID T, SID Ex)
  40         : EHFrameSID(EH), TextSID(T), ExceptTabSID(Ex) {}
  41     SID EHFrameSID;
  42     SID TextSID;
  43     SID ExceptTabSID;
  44   };
  45
  46   // When a module is loaded we save the SectionID of the EH frame section
  47   // in a table until we receive a request to register all unregistered
  48   // EH frame sections with the memory manager.
  49   SmallVector<EHFrameRelatedSections, 2> UnregisteredEHFrameSections;
  50
  51   RuntimeDyldMachO(RuntimeDyld::MemoryManager &MemMgr,
  52                    JITSymbolResolver &Resolver)
  53       : RuntimeDyldImpl(MemMgr, Resolver) {}
  54
  55   /// This convenience method uses memcpy to extract a contiguous addend (the
  56   /// addend size and offset are taken from the corresponding fields of the RE).
  57   int64_t memcpyAddend(const RelocationEntry &RE) const;
  58
  59   /// Given a relocation_iterator for a non-scattered relocation, construct a
  60   /// RelocationEntry and fill in the common fields. The 'Addend' field is *not*
  61   /// filled in, since immediate encodings are highly target/opcode specific.
  62   /// For targets/opcodes with simple, contiguous immediates (e.g. X86) the
  63   /// memcpyAddend method can be used to read the immediate.
  64   RelocationEntry getRelocationEntry(unsigned SectionID,
  65                                      const ObjectFile &BaseTObj,
  66                                      const relocation_iterator &RI) const {
  67     const MachOObjectFile &Obj =
  68       static_cast<const MachOObjectFile &>(BaseTObj);
  69     MachO::any_relocation_info RelInfo =
  70       Obj.getRelocation(RI->getRawDataRefImpl());
  71
  72     bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
  73     unsigned Size = Obj.getAnyRelocationLength(RelInfo);
  74     uint64_t Offset = RI->getOffset();
  75     MachO::RelocationInfoType RelType =
  76       static_cast<MachO::RelocationInfoType>(Obj.getAnyRelocationType(RelInfo));
  77
  78     return RelocationEntry(SectionID, Offset, RelType, 0, IsPCRel, Size);
  79   }
  80
  81   /// Process a scattered vanilla relocation.
  82   Expected<relocation_iterator>
  83   processScatteredVANILLA(unsigned SectionID, relocation_iterator RelI,
  84                           const ObjectFile &BaseObjT,
  85                           RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID,
  86                           bool TargetIsLocalThumbFunc = false);
  87
  88   /// Construct a RelocationValueRef representing the relocation target.
  89   /// For Symbols in known sections, this will return a RelocationValueRef
  90   /// representing a (SectionID, Offset) pair.
  91   /// For Symbols whose section is not known, this will return a
  92   /// (SymbolName, Offset) pair, where the Offset is taken from the instruction
  93   /// immediate (held in RE.Addend).
  94   /// In both cases the Addend field is *NOT* fixed up to be PC-relative. That
  95   /// should be done by the caller where appropriate by calling makePCRel on
  96   /// the RelocationValueRef.
  97   Expected<RelocationValueRef>
  98   getRelocationValueRef(const ObjectFile &BaseTObj,
  99                         const relocation_iterator &RI,
 100                         const RelocationEntry &RE,
 101                         ObjSectionToIDMap &ObjSectionToID);
 102
 103   /// Make the RelocationValueRef addend PC-relative.
 104   void makeValueAddendPCRel(RelocationValueRef &Value,
 105                             const relocation_iterator &RI,
 106                             unsigned OffsetToNextPC);
 107
 108   /// Dump information about the relocation entry (RE) and resolved value.
 109   void dumpRelocationToResolve(const RelocationEntry &RE, uint64_t Value) const;
 110
 111   // Return a section iterator for the section containing the given address.
 112   static section_iterator getSectionByAddress(const MachOObjectFile &Obj,
 113                                               uint64_t Addr);
 114
 115
 116   // Populate __pointers section.
 117   Error populateIndirectSymbolPointersSection(const MachOObjectFile &Obj,
 118                                               const SectionRef &PTSection,
 119                                               unsigned PTSectionID);
 120
 121 public:
 122
 123   /// Create a RuntimeDyldMachO instance for the given target architecture.
 124   static std::unique_ptr<RuntimeDyldMachO>
 125   create(Triple::ArchType Arch,
 126          RuntimeDyld::MemoryManager &MemMgr,
 127          JITSymbolResolver &Resolver);
 128
 129   std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
 130   loadObject(const object::ObjectFile &O) override;
 131
 132   SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; }
 133
 134   bool isCompatibleFile(const object::ObjectFile &Obj) const override;
 135 };
 136
 137 /// RuntimeDyldMachOTarget - Templated base class for generic MachO linker
 138 /// algorithms and data structures.
 139 ///
 140 /// Concrete, target specific sub-classes can be accessed via the impl()
 141 /// methods. (i.e. the RuntimeDyldMachO hierarchy uses the Curiously
 142 /// Recurring Template Idiom). Concrete subclasses for each target
 143 /// can be found in ./Targets.
 144 template <typename Impl>
 145 class RuntimeDyldMachOCRTPBase : public RuntimeDyldMachO {
 146 private:
 147   Impl &impl() { return static_cast<Impl &>(*this); }
 148   const Impl &impl() const { return static_cast<const Impl &>(*this); }
 149
 150   unsigned char *processFDE(uint8_t *P, int64_t DeltaForText,
 151                             int64_t DeltaForEH);
 152
 153 public:
 154   RuntimeDyldMachOCRTPBase(RuntimeDyld::MemoryManager &MemMgr,
 155                            JITSymbolResolver &Resolver)
 156     : RuntimeDyldMachO(MemMgr, Resolver) {}
 157
 158   Error finalizeLoad(const ObjectFile &Obj,
 159                      ObjSectionToIDMap &SectionMap) override;
 160   void registerEHFrames() override;
 161 };
 162
 163 } // end namespace llvm
 164
 165 #undef DEBUG_TYPE
 166
 167 #endif