1 //===-- RuntimeDyldImpl.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 // Interface for the implementations of runtime dynamic linker facilities. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_RUNTIME_DYLD_IMPL_H 15 #define LLVM_RUNTIME_DYLD_IMPL_H 16 17 #include "llvm/ExecutionEngine/RuntimeDyld.h" 18 #include "llvm/Object/ObjectFile.h" 19 #include "llvm/ADT/DenseMap.h" 20 #include "llvm/ADT/StringMap.h" 21 #include "llvm/ADT/Twine.h" 22 #include "llvm/ADT/SmallVector.h" 23 #include "llvm/Support/Memory.h" 24 #include "llvm/Support/MemoryBuffer.h" 25 #include "llvm/Support/system_error.h" 26 #include "llvm/Support/raw_ostream.h" 27 #include "llvm/Support/Debug.h" 28 #include "llvm/Support/ErrorHandling.h" 29 #include "llvm/ADT/Triple.h" 30 #include <map> 31 #include "llvm/Support/Format.h" 32 #include "ObjectImage.h" 33 34 using namespace llvm; 35 using namespace llvm::object; 36 37 namespace llvm { 38 39 class SectionEntry { 40 public: 41 uint8_t* Address; 42 size_t Size; 43 uint64_t LoadAddress; // For each section, the address it will be 44 // considered to live at for relocations. The same 45 // as the pointer to the above memory block for 46 // hosted JITs. 47 uintptr_t StubOffset; // It's used for architecturies with stub 48 // functions for far relocations like ARM. 49 uintptr_t ObjAddress; // Section address in object file. It's use for 50 // calculate MachO relocation addend 51 SectionEntry(uint8_t* address, size_t size, uintptr_t stubOffset, 52 uintptr_t objAddress) 53 : Address(address), Size(size), LoadAddress((uintptr_t)address), 54 StubOffset(stubOffset), ObjAddress(objAddress) {} 55 }; 56 57 class RelocationEntry { 58 public: 59 unsigned SectionID; // Section the relocation is contained in. 60 uintptr_t Offset; // Offset into the section for the relocation. 61 uint32_t Data; // Relocatino data. Including type of relocation 62 // and another flags and parameners from 63 intptr_t Addend; // Addend encoded in the instruction itself, if any, 64 // plus the offset into the source section for 65 // the symbol once the relocation is resolvable. 66 RelocationEntry(unsigned id, uint64_t offset, uint32_t data, int64_t addend) 67 : SectionID(id), Offset(offset), Data(data), Addend(addend) {} 68 }; 69 70 // Raw relocation data from object file 71 class ObjRelocationInfo { 72 public: 73 unsigned SectionID; 74 uint64_t Offset; 75 SymbolRef Symbol; 76 uint64_t Type; 77 int64_t AdditionalInfo; 78 }; 79 80 class RelocationValueRef { 81 public: 82 unsigned SectionID; 83 intptr_t Addend; 84 const char *SymbolName; 85 RelocationValueRef(): SectionID(0), Addend(0), SymbolName(0) {} 86 87 inline bool operator==(const RelocationValueRef &Other) const { 88 return std::memcmp(this, &Other, sizeof(RelocationValueRef)) == 0; 89 } 90 inline bool operator <(const RelocationValueRef &Other) const { 91 return std::memcmp(this, &Other, sizeof(RelocationValueRef)) < 0; 92 } 93 }; 94 95 class RuntimeDyldImpl { 96 protected: 97 // The MemoryManager to load objects into. 98 RTDyldMemoryManager *MemMgr; 99 100 // A list of emmitted sections. 101 typedef SmallVector<SectionEntry, 64> SectionList; 102 SectionList Sections; 103 104 // Keep a map of sections from object file to the SectionID which 105 // references it. 106 typedef std::map<SectionRef, unsigned> ObjSectionToIDMap; 107 108 // Master symbol table. As modules are loaded and external symbols are 109 // resolved, their addresses are stored here as a SectionID/Offset pair. 110 typedef std::pair<unsigned, uintptr_t> SymbolLoc; 111 StringMap<SymbolLoc> SymbolTable; 112 typedef DenseMap<const char*, SymbolLoc> LocalSymbolMap; 113 114 // Keep a map of common symbols to their sizes 115 typedef std::map<SymbolRef, unsigned> CommonSymbolMap; 116 117 // For each symbol, keep a list of relocations based on it. Anytime 118 // its address is reassigned (the JIT re-compiled the function, e.g.), 119 // the relocations get re-resolved. 120 // The symbol (or section) the relocation is sourced from is the Key 121 // in the relocation list where it's stored. 122 typedef SmallVector<RelocationEntry, 64> RelocationList; 123 // Relocations to sections already loaded. Indexed by SectionID which is the 124 // source of the address. The target where the address will be writen is 125 // SectionID/Offset in the relocation itself. 126 DenseMap<unsigned, RelocationList> Relocations; 127 // Relocations to external symbols that are not yet resolved. 128 // Indexed by symbol name. 129 StringMap<RelocationList> SymbolRelocations; 130 131 typedef std::map<RelocationValueRef, uintptr_t> StubMap; 132 133 Triple::ArchType Arch; 134 135 inline unsigned getMaxStubSize() { 136 if (Arch == Triple::arm || Arch == Triple::thumb) 137 return 8; // 32-bit instruction and 32-bit address 138 else 139 return 0; 140 } 141 142 bool HasError; 143 std::string ErrorStr; 144 145 // Set the error state and record an error string. 146 bool Error(const Twine &Msg) { 147 ErrorStr = Msg.str(); 148 HasError = true; 149 return true; 150 } 151 152 uint8_t *getSectionAddress(unsigned SectionID) { 153 return (uint8_t*)Sections[SectionID].Address; 154 } 155 156 /// \brief Emits a section containing common symbols. 157 /// \return SectionID. 158 unsigned emitCommonSymbols(ObjectImage &Obj, 159 const CommonSymbolMap &Map, 160 uint64_t TotalSize, 161 LocalSymbolMap &Symbols); 162 163 /// \brief Emits section data from the object file to the MemoryManager. 164 /// \param IsCode if it's true then allocateCodeSection() will be 165 /// used for emmits, else allocateDataSection() will be used. 166 /// \return SectionID. 167 unsigned emitSection(ObjectImage &Obj, 168 const SectionRef &Section, 169 bool IsCode); 170 171 /// \brief Find Section in LocalSections. If the secton is not found - emit 172 /// it and store in LocalSections. 173 /// \param IsCode if it's true then allocateCodeSection() will be 174 /// used for emmits, else allocateDataSection() will be used. 175 /// \return SectionID. 176 unsigned findOrEmitSection(ObjectImage &Obj, 177 const SectionRef &Section, 178 bool IsCode, 179 ObjSectionToIDMap &LocalSections); 180 181 /// \brief If Value.SymbolName is NULL then store relocation to the 182 /// Relocations, else store it in the SymbolRelocations. 183 void AddRelocation(const RelocationValueRef &Value, unsigned SectionID, 184 uintptr_t Offset, uint32_t RelType); 185 186 /// \brief Emits long jump instruction to Addr. 187 /// \return Pointer to the memory area for emitting target address. 188 uint8_t* createStubFunction(uint8_t *Addr); 189 190 /// \brief Resolves relocations from Relocs list with address from Value. 191 void resolveRelocationList(const RelocationList &Relocs, uint64_t Value); 192 void resolveRelocationEntry(const RelocationEntry &RE, uint64_t Value); 193 194 /// \brief A object file specific relocation resolver 195 /// \param Address Address to apply the relocation action 196 /// \param Value Target symbol address to apply the relocation action 197 /// \param Type object file specific relocation type 198 /// \param Addend A constant addend used to compute the value to be stored 199 /// into the relocatable field 200 virtual void resolveRelocation(uint8_t *LocalAddress, 201 uint64_t FinalAddress, 202 uint64_t Value, 203 uint32_t Type, 204 int64_t Addend) = 0; 205 206 /// \brief Parses the object file relocation and store it to Relocations 207 /// or SymbolRelocations. Its depend from object file type. 208 virtual void processRelocationRef(const ObjRelocationInfo &Rel, 209 ObjectImage &Obj, 210 ObjSectionToIDMap &ObjSectionToID, 211 LocalSymbolMap &Symbols, StubMap &Stubs) = 0; 212 213 void resolveSymbols(); 214 virtual ObjectImage *createObjectImage(const MemoryBuffer *InputBuffer); 215 virtual void handleObjectLoaded(ObjectImage *Obj) 216 { 217 // Subclasses may choose to retain this image if they have a use for it 218 delete Obj; 219 } 220 221 public: 222 RuntimeDyldImpl(RTDyldMemoryManager *mm) : MemMgr(mm), HasError(false) {} 223 224 virtual ~RuntimeDyldImpl(); 225 226 bool loadObject(const MemoryBuffer *InputBuffer); 227 228 void *getSymbolAddress(StringRef Name) { 229 // FIXME: Just look up as a function for now. Overly simple of course. 230 // Work in progress. 231 if (SymbolTable.find(Name) == SymbolTable.end()) 232 return 0; 233 SymbolLoc Loc = SymbolTable.lookup(Name); 234 return getSectionAddress(Loc.first) + Loc.second; 235 } 236 237 void resolveRelocations(); 238 239 void reassignSectionAddress(unsigned SectionID, uint64_t Addr); 240 241 void mapSectionAddress(void *LocalAddress, uint64_t TargetAddress); 242 243 // Is the linker in an error state? 244 bool hasError() { return HasError; } 245 246 // Mark the error condition as handled and continue. 247 void clearError() { HasError = false; } 248 249 // Get the error message. 250 StringRef getErrorString() { return ErrorStr; } 251 252 virtual bool isCompatibleFormat(const MemoryBuffer *InputBuffer) const = 0; 253 254 }; 255 256 } // end namespace llvm 257 258 259 #endif 260
