1 //===-- RuntimeDyldImpl.h - Run-time dynamic linker for MC-JIT --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Interface for the implementations of runtime dynamic linker facilities.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_RUNTIME_DYLD_IMPL_H
15 #define LLVM_RUNTIME_DYLD_IMPL_H
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"
31 #include "llvm/Support/Format.h"
34 using namespace llvm::object;
42 uint64_t LoadAddress; // For each section, the address it will be
43 // considered to live at for relocations. The same
44 // as the pointer to the above memory block for
46 uintptr_t StubOffset; // It's used for architecturies with stub
47 // functions for far relocations like ARM.
48 uintptr_t ObjAddress; // Section address in object file. It's use for
49 // calculate MachO relocation addend
50 SectionEntry(uint8_t* address, size_t size, uintptr_t stubOffset,
52 : Address(address), Size(size), LoadAddress((uintptr_t)address),
53 StubOffset(stubOffset), ObjAddress(objAddress) {}
56 class RelocationEntry {
58 unsigned SectionID; // Section the relocation is contained in.
59 uintptr_t Offset; // Offset into the section for the relocation.
60 uint32_t Data; // Relocatino data. Including type of relocation
61 // and another flags and parameners from
62 intptr_t Addend; // Addend encoded in the instruction itself, if any,
63 // plus the offset into the source section for
64 // the symbol once the relocation is resolvable.
65 RelocationEntry(unsigned id, uint64_t offset, uint32_t data, int64_t addend)
66 : SectionID(id), Offset(offset), Data(data), Addend(addend) {}
69 // Raw relocation data from object file
70 class ObjRelocationInfo {
76 int64_t AdditionalInfo;
79 class RelocationValueRef {
83 const char *SymbolName;
84 RelocationValueRef(): SectionID(0), Addend(0), SymbolName(0) {}
86 inline bool operator==(const RelocationValueRef &Other) const {
87 return std::memcmp(this, &Other, sizeof(RelocationValueRef)) == 0;
89 inline bool operator <(const RelocationValueRef &Other) const {
90 return std::memcmp(this, &Other, sizeof(RelocationValueRef)) < 0;
94 class RuntimeDyldImpl {
96 // The MemoryManager to load objects into.
97 RTDyldMemoryManager *MemMgr;
99 // A list of emmitted sections.
100 typedef SmallVector<SectionEntry, 64> SectionList;
101 SectionList Sections;
103 // Keep a map of sections from object file to the SectionID which
105 typedef std::map<SectionRef, unsigned> ObjSectionToIDMap;
107 // Master symbol table. As modules are loaded and external symbols are
108 // resolved, their addresses are stored here as a SectionID/Offset pair.
109 typedef std::pair<unsigned, uintptr_t> SymbolLoc;
110 StringMap<SymbolLoc> SymbolTable;
111 typedef DenseMap<const char*, SymbolLoc> LocalSymbolMap;
113 // For each symbol, keep a list of relocations based on it. Anytime
114 // its address is reassigned (the JIT re-compiled the function, e.g.),
115 // the relocations get re-resolved.
116 // The symbol (or section) the relocation is sourced from is the Key
117 // in the relocation list where it's stored.
118 typedef SmallVector<RelocationEntry, 64> RelocationList;
119 // Relocations to sections already loaded. Indexed by SectionID which is the
120 // source of the address. The target where the address will be writen is
121 // SectionID/Offset in the relocation itself.
122 DenseMap<unsigned, RelocationList> Relocations;
123 // Relocations to external symbols that are not yet resolved.
124 // Indexed by symbol name.
125 StringMap<RelocationList> SymbolRelocations;
127 typedef std::map<RelocationValueRef, uintptr_t> StubMap;
129 Triple::ArchType Arch;
131 inline unsigned getMaxStubSize() {
132 if (Arch == Triple::arm || Arch == Triple::thumb)
133 return 8; // 32-bit instruction and 32-bit address
139 std::string ErrorStr;
141 // Set the error state and record an error string.
142 bool Error(const Twine &Msg) {
143 ErrorStr = Msg.str();
148 uint8_t *getSectionAddress(unsigned SectionID) {
149 return (uint8_t*)Sections[SectionID].Address;
152 /// \brief Emits section data from the object file to the MemoryManager.
153 /// \param IsCode if it's true then allocateCodeSection() will be
154 /// used for emmits, else allocateDataSection() will be used.
155 /// \return SectionID.
156 unsigned emitSection(const SectionRef &Section, bool IsCode);
158 /// \brief Find Section in LocalSections. If the secton is not found - emit
159 /// it and store in LocalSections.
160 /// \param IsCode if it's true then allocateCodeSection() will be
161 /// used for emmits, else allocateDataSection() will be used.
162 /// \return SectionID.
163 unsigned findOrEmitSection(const SectionRef &Section, bool IsCode,
164 ObjSectionToIDMap &LocalSections);
166 /// \brief If Value.SymbolName is NULL then store relocation to the
167 /// Relocations, else store it in the SymbolRelocations.
168 void AddRelocation(const RelocationValueRef &Value, unsigned SectionID,
169 uintptr_t Offset, uint32_t RelType);
171 /// \brief Emits long jump instruction to Addr.
172 /// \return Pointer to the memory area for emitting target address.
173 uint8_t* createStubFunction(uint8_t *Addr);
175 /// \brief Resolves relocations from Relocs list with address from Value.
176 void resolveRelocationList(const RelocationList &Relocs, uint64_t Value);
177 void resolveRelocationEntry(const RelocationEntry &RE, uint64_t Value);
179 /// \brief A object file specific relocation resolver
180 /// \param Address Address to apply the relocation action
181 /// \param Value Target symbol address to apply the relocation action
182 /// \param Type object file specific relocation type
183 /// \param Addend A constant addend used to compute the value to be stored
184 /// into the relocatable field
185 virtual void resolveRelocation(uint8_t *LocalAddress,
186 uint64_t FinalAddress,
191 /// \brief Parses the object file relocation and store it to Relocations
192 /// or SymbolRelocations. Its depend from object file type.
193 virtual void processRelocationRef(const ObjRelocationInfo &Rel,
194 const ObjectFile &Obj,
195 ObjSectionToIDMap &ObjSectionToID,
196 LocalSymbolMap &Symbols, StubMap &Stubs) = 0;
198 void resolveSymbols();
200 RuntimeDyldImpl(RTDyldMemoryManager *mm) : MemMgr(mm), HasError(false) {}
202 virtual ~RuntimeDyldImpl();
204 bool loadObject(const MemoryBuffer *InputBuffer);
206 void *getSymbolAddress(StringRef Name) {
207 // FIXME: Just look up as a function for now. Overly simple of course.
209 if (SymbolTable.find(Name) == SymbolTable.end())
211 SymbolLoc Loc = SymbolTable.lookup(Name);
212 return getSectionAddress(Loc.first) + Loc.second;
215 void resolveRelocations();
217 void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
219 void mapSectionAddress(void *LocalAddress, uint64_t TargetAddress);
221 // Is the linker in an error state?
222 bool hasError() { return HasError; }
224 // Mark the error condition as handled and continue.
225 void clearError() { HasError = false; }
227 // Get the error message.
228 StringRef getErrorString() { return ErrorStr; }
230 virtual bool isCompatibleFormat(const MemoryBuffer *InputBuffer) const = 0;
234 } // end namespace llvm