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"
32 #include "ObjectImage.h"
35 using namespace llvm::object;
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
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,
53 : Address(address), Size(size), LoadAddress((uintptr_t)address),
54 StubOffset(stubOffset), ObjAddress(objAddress) {}
57 class RelocationEntry {
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) {}
70 // Raw relocation data from object file
71 class ObjRelocationInfo {
77 int64_t AdditionalInfo;
80 class RelocationValueRef {
84 const char *SymbolName;
85 RelocationValueRef(): SectionID(0), Addend(0), SymbolName(0) {}
87 inline bool operator==(const RelocationValueRef &Other) const {
88 return std::memcmp(this, &Other, sizeof(RelocationValueRef)) == 0;
90 inline bool operator <(const RelocationValueRef &Other) const {
91 return std::memcmp(this, &Other, sizeof(RelocationValueRef)) < 0;
95 class RuntimeDyldImpl {
97 // The MemoryManager to load objects into.
98 RTDyldMemoryManager *MemMgr;
100 // A list of emmitted sections.
101 typedef SmallVector<SectionEntry, 64> SectionList;
102 SectionList Sections;
104 // Keep a map of sections from object file to the SectionID which
106 typedef std::map<SectionRef, unsigned> ObjSectionToIDMap;
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;
114 // Keep a map of common symbols to their sizes
115 typedef std::map<SymbolRef, unsigned> CommonSymbolMap;
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;
131 typedef std::map<RelocationValueRef, uintptr_t> StubMap;
133 Triple::ArchType Arch;
135 inline unsigned getMaxStubSize() {
136 if (Arch == Triple::arm || Arch == Triple::thumb)
137 return 8; // 32-bit instruction and 32-bit address
143 std::string ErrorStr;
145 // Set the error state and record an error string.
146 bool Error(const Twine &Msg) {
147 ErrorStr = Msg.str();
152 uint8_t *getSectionAddress(unsigned SectionID) {
153 return (uint8_t*)Sections[SectionID].Address;
156 /// \brief Emits a section containing common symbols.
157 /// \return SectionID.
158 unsigned emitCommonSymbols(ObjectImage &Obj,
159 const CommonSymbolMap &Map,
161 LocalSymbolMap &Symbols);
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,
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,
179 ObjSectionToIDMap &LocalSections);
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);
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);
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);
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,
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,
210 ObjSectionToIDMap &ObjSectionToID,
211 LocalSymbolMap &Symbols, StubMap &Stubs) = 0;
213 void resolveSymbols();
214 virtual ObjectImage *createObjectImage(const MemoryBuffer *InputBuffer);
215 virtual void handleObjectLoaded(ObjectImage *Obj)
217 // Subclasses may choose to retain this image if they have a use for it
222 RuntimeDyldImpl(RTDyldMemoryManager *mm) : MemMgr(mm), HasError(false) {}
224 virtual ~RuntimeDyldImpl();
226 bool loadObject(const MemoryBuffer *InputBuffer);
228 void *getSymbolAddress(StringRef Name) {
229 // FIXME: Just look up as a function for now. Overly simple of course.
231 if (SymbolTable.find(Name) == SymbolTable.end())
233 SymbolLoc Loc = SymbolTable.lookup(Name);
234 return getSectionAddress(Loc.first) + Loc.second;
237 void resolveRelocations();
239 void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
241 void mapSectionAddress(void *LocalAddress, uint64_t TargetAddress);
243 // Is the linker in an error state?
244 bool hasError() { return HasError; }
246 // Mark the error condition as handled and continue.
247 void clearError() { HasError = false; }
249 // Get the error message.
250 StringRef getErrorString() { return ErrorStr; }
252 virtual bool isCompatibleFormat(const MemoryBuffer *InputBuffer) const = 0;
256 } // end namespace llvm