1 //===-- RuntimeDyldELF.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 // ELF support for MC-JIT runtime dynamic linker. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDELF_H 14 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDELF_H 15 16 #include "RuntimeDyldImpl.h" 17 #include "llvm/ADT/DenseMap.h" 18 19 using namespace llvm; 20 21 namespace llvm { 22 namespace object { 23 class ELFObjectFileBase; 24 } 25 26 class RuntimeDyldELF : public RuntimeDyldImpl { 27 28 void resolveRelocation(const SectionEntry &Section, uint64_t Offset, 29 uint64_t Value, uint32_t Type, int64_t Addend, 30 uint64_t SymOffset = 0, SID SectionID = 0); 31 32 void resolveX86_64Relocation(const SectionEntry &Section, uint64_t Offset, 33 uint64_t Value, uint32_t Type, int64_t Addend, 34 uint64_t SymOffset); 35 36 void resolveX86Relocation(const SectionEntry &Section, uint64_t Offset, 37 uint32_t Value, uint32_t Type, int32_t Addend); 38 39 void resolveAArch64Relocation(const SectionEntry &Section, uint64_t Offset, 40 uint64_t Value, uint32_t Type, int64_t Addend); 41 42 bool resolveAArch64ShortBranch(unsigned SectionID, relocation_iterator RelI, 43 const RelocationValueRef &Value); 44 45 void resolveAArch64Branch(unsigned SectionID, const RelocationValueRef &Value, 46 relocation_iterator RelI, StubMap &Stubs); 47 48 void resolveARMRelocation(const SectionEntry &Section, uint64_t Offset, 49 uint32_t Value, uint32_t Type, int32_t Addend); 50 51 void resolvePPC32Relocation(const SectionEntry &Section, uint64_t Offset, 52 uint64_t Value, uint32_t Type, int64_t Addend); 53 54 void resolvePPC64Relocation(const SectionEntry &Section, uint64_t Offset, 55 uint64_t Value, uint32_t Type, int64_t Addend); 56 57 void resolveSystemZRelocation(const SectionEntry &Section, uint64_t Offset, 58 uint64_t Value, uint32_t Type, int64_t Addend); 59 60 void resolveBPFRelocation(const SectionEntry &Section, uint64_t Offset, 61 uint64_t Value, uint32_t Type, int64_t Addend); 62 63 unsigned getMaxStubSize() const override { 64 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 65 return 20; // movz; movk; movk; movk; br 66 if (Arch == Triple::arm || Arch == Triple::thumb) 67 return 8; // 32-bit instruction and 32-bit address 68 else if (IsMipsO32ABI || IsMipsN32ABI) 69 return 16; 70 else if (IsMipsN64ABI) 71 return 32; 72 else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) 73 return 44; 74 else if (Arch == Triple::x86_64) 75 return 6; // 2-byte jmp instruction + 32-bit relative address 76 else if (Arch == Triple::systemz) 77 return 16; 78 else 79 return 0; 80 } 81 82 unsigned getStubAlignment() override { 83 if (Arch == Triple::systemz) 84 return 8; 85 else 86 return 1; 87 } 88 89 void setMipsABI(const ObjectFile &Obj) override; 90 91 Error findPPC64TOCSection(const ELFObjectFileBase &Obj, 92 ObjSectionToIDMap &LocalSections, 93 RelocationValueRef &Rel); 94 Error findOPDEntrySection(const ELFObjectFileBase &Obj, 95 ObjSectionToIDMap &LocalSections, 96 RelocationValueRef &Rel); 97 protected: 98 size_t getGOTEntrySize() override; 99 100 private: 101 SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; } 102 103 // Allocate no GOT entries for use in the given section. 104 uint64_t allocateGOTEntries(unsigned no); 105 106 // Find GOT entry corresponding to relocation or create new one. 107 uint64_t findOrAllocGOTEntry(const RelocationValueRef &Value, 108 unsigned GOTRelType); 109 110 // Resolve the relvative address of GOTOffset in Section ID and place 111 // it at the given Offset 112 void resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset, 113 uint64_t GOTOffset, uint32_t Type); 114 115 // For a GOT entry referenced from SectionID, compute a relocation entry 116 // that will place the final resolved value in the GOT slot 117 RelocationEntry computeGOTOffsetRE(uint64_t GOTOffset, uint64_t SymbolOffset, 118 unsigned Type); 119 120 // Compute the address in memory where we can find the placeholder 121 void *computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const; 122 123 // Split out common case for createing the RelocationEntry for when the relocation requires 124 // no particular advanced processing. 125 void processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value); 126 127 // Return matching *LO16 relocation (Mips specific) 128 uint32_t getMatchingLoRelocation(uint32_t RelType, 129 bool IsLocal = false) const; 130 131 // The tentative ID for the GOT section 132 unsigned GOTSectionID; 133 134 // Records the current number of allocated slots in the GOT 135 // (This would be equivalent to GOTEntries.size() were it not for relocations 136 // that consume more than one slot) 137 unsigned CurrentGOTIndex; 138 139 protected: 140 // A map from section to a GOT section that has entries for section's GOT 141 // relocations. (Mips64 specific) 142 DenseMap<SID, SID> SectionToGOTMap; 143 144 private: 145 // A map to avoid duplicate got entries (Mips64 specific) 146 StringMap<uint64_t> GOTSymbolOffsets; 147 148 // *HI16 relocations will be added for resolving when we find matching 149 // *LO16 part. (Mips specific) 150 SmallVector<std::pair<RelocationValueRef, RelocationEntry>, 8> PendingRelocs; 151 152 // When a module is loaded we save the SectionID of the EH frame section 153 // in a table until we receive a request to register all unregistered 154 // EH frame sections with the memory manager. 155 SmallVector<SID, 2> UnregisteredEHFrameSections; 156 157 // Map between GOT relocation value and corresponding GOT offset 158 std::map<RelocationValueRef, uint64_t> GOTOffsetMap; 159 160 bool relocationNeedsGot(const RelocationRef &R) const override; 161 bool relocationNeedsStub(const RelocationRef &R) const override; 162 163 public: 164 RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 165 JITSymbolResolver &Resolver); 166 ~RuntimeDyldELF() override; 167 168 static std::unique_ptr<RuntimeDyldELF> 169 create(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MemMgr, 170 JITSymbolResolver &Resolver); 171 172 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 173 loadObject(const object::ObjectFile &O) override; 174 175 void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override; 176 Expected<relocation_iterator> 177 processRelocationRef(unsigned SectionID, relocation_iterator RelI, 178 const ObjectFile &Obj, 179 ObjSectionToIDMap &ObjSectionToID, 180 StubMap &Stubs) override; 181 bool isCompatibleFile(const object::ObjectFile &Obj) const override; 182 void registerEHFrames() override; 183 Error finalizeLoad(const ObjectFile &Obj, 184 ObjSectionToIDMap &SectionMap) override; 185 }; 186 187 } // end namespace llvm 188 189 #endif 190