1 //===-- RuntimeDyldELF.h - Run-time dynamic linker for MC-JIT ---*- 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 // ELF support for MC-JIT runtime dynamic linker. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDELF_H 15 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDELF_H 16 17 #include "RuntimeDyldImpl.h" 18 #include "llvm/ADT/DenseMap.h" 19 20 using namespace llvm; 21 22 namespace llvm { 23 namespace object { 24 class ELFObjectFileBase; 25 } 26 27 class RuntimeDyldELF : public RuntimeDyldImpl { 28 29 void resolveRelocation(const SectionEntry &Section, uint64_t Offset, 30 uint64_t Value, uint32_t Type, int64_t Addend, 31 uint64_t SymOffset = 0, SID SectionID = 0); 32 33 void resolveX86_64Relocation(const SectionEntry &Section, uint64_t Offset, 34 uint64_t Value, uint32_t Type, int64_t Addend, 35 uint64_t SymOffset); 36 37 void resolveX86Relocation(const SectionEntry &Section, uint64_t Offset, 38 uint32_t Value, uint32_t Type, int32_t Addend); 39 40 void resolveAArch64Relocation(const SectionEntry &Section, uint64_t Offset, 41 uint64_t Value, uint32_t Type, int64_t Addend); 42 43 bool resolveAArch64ShortBranch(unsigned SectionID, relocation_iterator RelI, 44 const RelocationValueRef &Value); 45 46 void resolveAArch64Branch(unsigned SectionID, const RelocationValueRef &Value, 47 relocation_iterator RelI, StubMap &Stubs); 48 49 void resolveARMRelocation(const SectionEntry &Section, uint64_t Offset, 50 uint32_t Value, uint32_t Type, int32_t Addend); 51 52 void resolvePPC32Relocation(const SectionEntry &Section, uint64_t Offset, 53 uint64_t Value, uint32_t Type, int64_t Addend); 54 55 void resolvePPC64Relocation(const SectionEntry &Section, uint64_t Offset, 56 uint64_t Value, uint32_t Type, int64_t Addend); 57 58 void resolveSystemZRelocation(const SectionEntry &Section, uint64_t Offset, 59 uint64_t Value, uint32_t Type, int64_t Addend); 60 61 void resolveBPFRelocation(const SectionEntry &Section, uint64_t Offset, 62 uint64_t Value, uint32_t Type, int64_t Addend); 63 getMaxStubSize()64 unsigned getMaxStubSize() override { 65 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 66 return 20; // movz; movk; movk; movk; br 67 if (Arch == Triple::arm || Arch == Triple::thumb) 68 return 8; // 32-bit instruction and 32-bit address 69 else if (IsMipsO32ABI || IsMipsN32ABI) 70 return 16; 71 else if (IsMipsN64ABI) 72 return 32; 73 else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) 74 return 44; 75 else if (Arch == Triple::x86_64) 76 return 6; // 2-byte jmp instruction + 32-bit relative address 77 else if (Arch == Triple::systemz) 78 return 16; 79 else 80 return 0; 81 } 82 getStubAlignment()83 unsigned getStubAlignment() override { 84 if (Arch == Triple::systemz) 85 return 8; 86 else 87 return 1; 88 } 89 90 void setMipsABI(const ObjectFile &Obj) override; 91 92 Error findPPC64TOCSection(const ELFObjectFileBase &Obj, 93 ObjSectionToIDMap &LocalSections, 94 RelocationValueRef &Rel); 95 Error findOPDEntrySection(const ELFObjectFileBase &Obj, 96 ObjSectionToIDMap &LocalSections, 97 RelocationValueRef &Rel); 98 protected: 99 size_t getGOTEntrySize() override; 100 101 private: getSection(unsigned SectionID)102 SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; } 103 104 // Allocate no GOT entries for use in the given section. 105 uint64_t allocateGOTEntries(unsigned no); 106 107 // Find GOT entry corresponding to relocation or create new one. 108 uint64_t findOrAllocGOTEntry(const RelocationValueRef &Value, 109 unsigned GOTRelType); 110 111 // Resolve the relvative address of GOTOffset in Section ID and place 112 // it at the given Offset 113 void resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset, 114 uint64_t GOTOffset, uint32_t Type); 115 116 // For a GOT entry referenced from SectionID, compute a relocation entry 117 // that will place the final resolved value in the GOT slot 118 RelocationEntry computeGOTOffsetRE(uint64_t GOTOffset, uint64_t SymbolOffset, 119 unsigned Type); 120 121 // Compute the address in memory where we can find the placeholder 122 void *computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const; 123 124 // Split out common case for createing the RelocationEntry for when the relocation requires 125 // no particular advanced processing. 126 void processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value); 127 128 // Return matching *LO16 relocation (Mips specific) 129 uint32_t getMatchingLoRelocation(uint32_t RelType, 130 bool IsLocal = false) const; 131 132 // The tentative ID for the GOT section 133 unsigned GOTSectionID; 134 135 // Records the current number of allocated slots in the GOT 136 // (This would be equivalent to GOTEntries.size() were it not for relocations 137 // that consume more than one slot) 138 unsigned CurrentGOTIndex; 139 140 protected: 141 // A map from section to a GOT section that has entries for section's GOT 142 // relocations. (Mips64 specific) 143 DenseMap<SID, SID> SectionToGOTMap; 144 145 private: 146 // A map to avoid duplicate got entries (Mips64 specific) 147 StringMap<uint64_t> GOTSymbolOffsets; 148 149 // *HI16 relocations will be added for resolving when we find matching 150 // *LO16 part. (Mips specific) 151 SmallVector<std::pair<RelocationValueRef, RelocationEntry>, 8> PendingRelocs; 152 153 // When a module is loaded we save the SectionID of the EH frame section 154 // in a table until we receive a request to register all unregistered 155 // EH frame sections with the memory manager. 156 SmallVector<SID, 2> UnregisteredEHFrameSections; 157 158 // Map between GOT relocation value and corresponding GOT offset 159 std::map<RelocationValueRef, uint64_t> GOTOffsetMap; 160 161 bool relocationNeedsGot(const RelocationRef &R) const override; 162 bool relocationNeedsStub(const RelocationRef &R) const override; 163 164 public: 165 RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 166 JITSymbolResolver &Resolver); 167 ~RuntimeDyldELF() override; 168 169 static std::unique_ptr<RuntimeDyldELF> 170 create(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MemMgr, 171 JITSymbolResolver &Resolver); 172 173 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 174 loadObject(const object::ObjectFile &O) override; 175 176 void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override; 177 Expected<relocation_iterator> 178 processRelocationRef(unsigned SectionID, relocation_iterator RelI, 179 const ObjectFile &Obj, 180 ObjSectionToIDMap &ObjSectionToID, 181 StubMap &Stubs) override; 182 bool isCompatibleFile(const object::ObjectFile &Obj) const override; 183 void registerEHFrames() override; 184 Error finalizeLoad(const ObjectFile &Obj, 185 ObjSectionToIDMap &SectionMap) override; 186 }; 187 188 } // end namespace llvm 189 190 #endif 191