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