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 168