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_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDIMPL_H
15 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDIMPL_H
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/SmallVector.h"
19 #include "llvm/ADT/StringMap.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
22 #include "llvm/ExecutionEngine/RuntimeDyld.h"
23 #include "llvm/ExecutionEngine/RuntimeDyldChecker.h"
24 #include "llvm/Object/ObjectFile.h"
25 #include "llvm/Support/Debug.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/Format.h"
28 #include "llvm/Support/Host.h"
29 #include "llvm/Support/Mutex.h"
30 #include "llvm/Support/SwapByteOrder.h"
31 #include "llvm/Support/raw_ostream.h"
33 #include <system_error>
36 using namespace llvm::object;
40 // Helper for extensive error checking in debug builds.
41 inline std::error_code Check(std::error_code Err) {
43 report_fatal_error(Err.message());
50 /// SectionEntry - represents a section emitted into memory by the dynamic
53 /// Name - section name.
56 /// Address - address in the linker's memory where the section resides.
59 /// Size - section size. Doesn't include the stubs.
62 /// LoadAddress - the address of the section in the target process's memory.
63 /// Used for situations in which JIT-ed code is being executed in the address
64 /// space of a separate process. If the code executes in the same address
65 /// space where it was JIT-ed, this just equals Address.
68 /// StubOffset - used for architectures with stub functions for far
69 /// relocations (like ARM).
72 /// ObjAddress - address of the section in the in-memory object file. Used
73 /// for calculating relocations in some object formats (like MachO).
77 SectionEntry(StringRef name, uint8_t *address, size_t size,
79 : Name(name), Address(address), Size(size),
80 LoadAddress(reinterpret_cast<uintptr_t>(address)), StubOffset(size),
81 ObjAddress(objAddress) {}
83 StringRef getName() const { return Name; }
85 uint8_t *getAddress() const { return Address; }
87 /// \brief Return the address of this section with an offset.
88 uint8_t *getAddressWithOffset(unsigned OffsetBytes) const {
89 return Address + OffsetBytes;
92 size_t getSize() const { return Size; }
94 uint64_t getLoadAddress() const { return LoadAddress; }
95 void setLoadAddress(uint64_t LA) { LoadAddress = LA; }
97 /// \brief Return the load address of this section with an offset.
98 uint64_t getLoadAddressWithOffset(unsigned OffsetBytes) const {
99 return LoadAddress + OffsetBytes;
102 uintptr_t getStubOffset() const { return StubOffset; }
104 void advanceStubOffset(unsigned StubSize) { StubOffset += StubSize; }
106 uintptr_t getObjAddress() const { return ObjAddress; }
109 /// RelocationEntry - used to represent relocations internally in the dynamic
111 class RelocationEntry {
113 /// SectionID - the section this relocation points to.
116 /// Offset - offset into the section.
119 /// RelType - relocation type.
122 /// Addend - the relocation addend encoded in the instruction itself. Also
123 /// used to make a relocation section relative instead of symbol relative.
131 /// SymOffset - Section offset of the relocation entry's symbol (used for GOT
135 SectionPair Sections;
138 /// True if this is a PCRel relocation (MachO specific).
141 /// The size of this relocation (MachO specific).
144 RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend)
145 : SectionID(id), Offset(offset), RelType(type), Addend(addend),
146 SymOffset(0), IsPCRel(false), Size(0) {}
148 RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend,
150 : SectionID(id), Offset(offset), RelType(type), Addend(addend),
151 SymOffset(symoffset), IsPCRel(false), Size(0) {}
153 RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend,
154 bool IsPCRel, unsigned Size)
155 : SectionID(id), Offset(offset), RelType(type), Addend(addend),
156 SymOffset(0), IsPCRel(IsPCRel), Size(Size) {}
158 RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend,
159 unsigned SectionA, uint64_t SectionAOffset, unsigned SectionB,
160 uint64_t SectionBOffset, bool IsPCRel, unsigned Size)
161 : SectionID(id), Offset(offset), RelType(type),
162 Addend(SectionAOffset - SectionBOffset + addend), IsPCRel(IsPCRel),
164 Sections.SectionA = SectionA;
165 Sections.SectionB = SectionB;
169 class RelocationValueRef {
174 const char *SymbolName;
175 RelocationValueRef() : SectionID(0), Offset(0), Addend(0),
176 SymbolName(nullptr) {}
178 inline bool operator==(const RelocationValueRef &Other) const {
179 return SectionID == Other.SectionID && Offset == Other.Offset &&
180 Addend == Other.Addend && SymbolName == Other.SymbolName;
182 inline bool operator<(const RelocationValueRef &Other) const {
183 if (SectionID != Other.SectionID)
184 return SectionID < Other.SectionID;
185 if (Offset != Other.Offset)
186 return Offset < Other.Offset;
187 if (Addend != Other.Addend)
188 return Addend < Other.Addend;
189 return SymbolName < Other.SymbolName;
193 /// @brief Symbol info for RuntimeDyld.
194 class SymbolTableEntry : public JITSymbolBase {
197 : JITSymbolBase(JITSymbolFlags::None), Offset(0), SectionID(0) {}
199 SymbolTableEntry(unsigned SectionID, uint64_t Offset, JITSymbolFlags Flags)
200 : JITSymbolBase(Flags), Offset(Offset), SectionID(SectionID) {}
202 unsigned getSectionID() const { return SectionID; }
203 uint64_t getOffset() const { return Offset; }
210 typedef StringMap<SymbolTableEntry> RTDyldSymbolTable;
212 class RuntimeDyldImpl {
213 friend class RuntimeDyld::LoadedObjectInfo;
214 friend class RuntimeDyldCheckerImpl;
216 static const unsigned AbsoluteSymbolSection = ~0U;
218 // The MemoryManager to load objects into.
219 RuntimeDyld::MemoryManager &MemMgr;
221 // The symbol resolver to use for external symbols.
222 RuntimeDyld::SymbolResolver &Resolver;
224 // Attached RuntimeDyldChecker instance. Null if no instance attached.
225 RuntimeDyldCheckerImpl *Checker;
227 // A list of all sections emitted by the dynamic linker. These sections are
228 // referenced in the code by means of their index in this list - SectionID.
229 typedef SmallVector<SectionEntry, 64> SectionList;
230 SectionList Sections;
232 typedef unsigned SID; // Type for SectionIDs
233 #define RTDYLD_INVALID_SECTION_ID ((RuntimeDyldImpl::SID)(-1))
235 // Keep a map of sections from object file to the SectionID which
237 typedef std::map<SectionRef, unsigned> ObjSectionToIDMap;
239 // A global symbol table for symbols from all loaded modules.
240 RTDyldSymbolTable GlobalSymbolTable;
242 // Keep a map of common symbols to their info pairs
243 typedef std::vector<SymbolRef> CommonSymbolList;
245 // For each symbol, keep a list of relocations based on it. Anytime
246 // its address is reassigned (the JIT re-compiled the function, e.g.),
247 // the relocations get re-resolved.
248 // The symbol (or section) the relocation is sourced from is the Key
249 // in the relocation list where it's stored.
250 typedef SmallVector<RelocationEntry, 64> RelocationList;
251 // Relocations to sections already loaded. Indexed by SectionID which is the
252 // source of the address. The target where the address will be written is
253 // SectionID/Offset in the relocation itself.
254 DenseMap<unsigned, RelocationList> Relocations;
256 // Relocations to external symbols that are not yet resolved. Symbols are
257 // external when they aren't found in the global symbol table of all loaded
258 // modules. This map is indexed by symbol name.
259 StringMap<RelocationList> ExternalSymbolRelocations;
262 typedef std::map<RelocationValueRef, uintptr_t> StubMap;
264 Triple::ArchType Arch;
265 bool IsTargetLittleEndian;
269 // True if all sections should be passed to the memory manager, false if only
270 // sections containing relocations should be. Defaults to 'false'.
271 bool ProcessAllSections;
273 // This mutex prevents simultaneously loading objects from two different
274 // threads. This keeps us from having to protect individual data structures
275 // and guarantees that section allocation requests to the memory manager
276 // won't be interleaved between modules. It is also used in mapSectionAddress
277 // and resolveRelocations to protect write access to internal data structures.
279 // loadObject may be called on the same thread during the handling of of
280 // processRelocations, and that's OK. The handling of the relocation lists
281 // is written in such a way as to work correctly if new elements are added to
282 // the end of the list while the list is being processed.
285 virtual unsigned getMaxStubSize() = 0;
286 virtual unsigned getStubAlignment() = 0;
289 std::string ErrorStr;
291 // Set the error state and record an error string.
292 bool Error(const Twine &Msg) {
293 ErrorStr = Msg.str();
298 uint64_t getSectionLoadAddress(unsigned SectionID) const {
299 return Sections[SectionID].getLoadAddress();
302 uint8_t *getSectionAddress(unsigned SectionID) const {
303 return Sections[SectionID].getAddress();
306 void writeInt16BE(uint8_t *Addr, uint16_t Value) {
307 if (IsTargetLittleEndian)
308 sys::swapByteOrder(Value);
309 *Addr = (Value >> 8) & 0xFF;
310 *(Addr + 1) = Value & 0xFF;
313 void writeInt32BE(uint8_t *Addr, uint32_t Value) {
314 if (IsTargetLittleEndian)
315 sys::swapByteOrder(Value);
316 *Addr = (Value >> 24) & 0xFF;
317 *(Addr + 1) = (Value >> 16) & 0xFF;
318 *(Addr + 2) = (Value >> 8) & 0xFF;
319 *(Addr + 3) = Value & 0xFF;
322 void writeInt64BE(uint8_t *Addr, uint64_t Value) {
323 if (IsTargetLittleEndian)
324 sys::swapByteOrder(Value);
325 *Addr = (Value >> 56) & 0xFF;
326 *(Addr + 1) = (Value >> 48) & 0xFF;
327 *(Addr + 2) = (Value >> 40) & 0xFF;
328 *(Addr + 3) = (Value >> 32) & 0xFF;
329 *(Addr + 4) = (Value >> 24) & 0xFF;
330 *(Addr + 5) = (Value >> 16) & 0xFF;
331 *(Addr + 6) = (Value >> 8) & 0xFF;
332 *(Addr + 7) = Value & 0xFF;
335 virtual void setMipsABI(const ObjectFile &Obj) {
336 IsMipsO32ABI = false;
337 IsMipsN64ABI = false;
340 /// Endian-aware read Read the least significant Size bytes from Src.
341 uint64_t readBytesUnaligned(uint8_t *Src, unsigned Size) const;
343 /// Endian-aware write. Write the least significant Size bytes from Value to
345 void writeBytesUnaligned(uint64_t Value, uint8_t *Dst, unsigned Size) const;
347 /// \brief Given the common symbols discovered in the object file, emit a
348 /// new section for them and update the symbol mappings in the object and
350 void emitCommonSymbols(const ObjectFile &Obj, CommonSymbolList &CommonSymbols);
352 /// \brief Emits section data from the object file to the MemoryManager.
353 /// \param IsCode if it's true then allocateCodeSection() will be
354 /// used for emits, else allocateDataSection() will be used.
355 /// \return SectionID.
356 unsigned emitSection(const ObjectFile &Obj, const SectionRef &Section,
359 /// \brief Find Section in LocalSections. If the secton is not found - emit
360 /// it and store in LocalSections.
361 /// \param IsCode if it's true then allocateCodeSection() will be
362 /// used for emmits, else allocateDataSection() will be used.
363 /// \return SectionID.
364 unsigned findOrEmitSection(const ObjectFile &Obj, const SectionRef &Section,
365 bool IsCode, ObjSectionToIDMap &LocalSections);
367 // \brief Add a relocation entry that uses the given section.
368 void addRelocationForSection(const RelocationEntry &RE, unsigned SectionID);
370 // \brief Add a relocation entry that uses the given symbol. This symbol may
371 // be found in the global symbol table, or it may be external.
372 void addRelocationForSymbol(const RelocationEntry &RE, StringRef SymbolName);
374 /// \brief Emits long jump instruction to Addr.
375 /// \return Pointer to the memory area for emitting target address.
376 uint8_t *createStubFunction(uint8_t *Addr, unsigned AbiVariant = 0);
378 /// \brief Resolves relocations from Relocs list with address from Value.
379 void resolveRelocationList(const RelocationList &Relocs, uint64_t Value);
381 /// \brief A object file specific relocation resolver
382 /// \param RE The relocation to be resolved
383 /// \param Value Target symbol address to apply the relocation action
384 virtual void resolveRelocation(const RelocationEntry &RE, uint64_t Value) = 0;
386 /// \brief Parses one or more object file relocations (some object files use
387 /// relocation pairs) and stores it to Relocations or SymbolRelocations
388 /// (this depends on the object file type).
389 /// \return Iterator to the next relocation that needs to be parsed.
390 virtual relocation_iterator
391 processRelocationRef(unsigned SectionID, relocation_iterator RelI,
392 const ObjectFile &Obj, ObjSectionToIDMap &ObjSectionToID,
395 /// \brief Resolve relocations to external symbols.
396 void resolveExternalSymbols();
398 // \brief Compute an upper bound of the memory that is required to load all
400 void computeTotalAllocSize(const ObjectFile &Obj, uint64_t &CodeSize,
401 uint64_t &DataSizeRO, uint64_t &DataSizeRW);
403 // \brief Compute the stub buffer size required for a section
404 unsigned computeSectionStubBufSize(const ObjectFile &Obj,
405 const SectionRef &Section);
407 // \brief Implementation of the generic part of the loadObject algorithm.
408 ObjSectionToIDMap loadObjectImpl(const object::ObjectFile &Obj);
411 RuntimeDyldImpl(RuntimeDyld::MemoryManager &MemMgr,
412 RuntimeDyld::SymbolResolver &Resolver)
413 : MemMgr(MemMgr), Resolver(Resolver), Checker(nullptr),
414 ProcessAllSections(false), HasError(false) {
417 virtual ~RuntimeDyldImpl();
419 void setProcessAllSections(bool ProcessAllSections) {
420 this->ProcessAllSections = ProcessAllSections;
423 void setRuntimeDyldChecker(RuntimeDyldCheckerImpl *Checker) {
424 this->Checker = Checker;
427 virtual std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
428 loadObject(const object::ObjectFile &Obj) = 0;
430 uint8_t* getSymbolLocalAddress(StringRef Name) const {
431 // FIXME: Just look up as a function for now. Overly simple of course.
433 RTDyldSymbolTable::const_iterator pos = GlobalSymbolTable.find(Name);
434 if (pos == GlobalSymbolTable.end())
436 const auto &SymInfo = pos->second;
437 // Absolute symbols do not have a local address.
438 if (SymInfo.getSectionID() == AbsoluteSymbolSection)
440 return getSectionAddress(SymInfo.getSectionID()) + SymInfo.getOffset();
443 RuntimeDyld::SymbolInfo getSymbol(StringRef Name) const {
444 // FIXME: Just look up as a function for now. Overly simple of course.
446 RTDyldSymbolTable::const_iterator pos = GlobalSymbolTable.find(Name);
447 if (pos == GlobalSymbolTable.end())
449 const auto &SymEntry = pos->second;
450 uint64_t SectionAddr = 0;
451 if (SymEntry.getSectionID() != AbsoluteSymbolSection)
452 SectionAddr = getSectionLoadAddress(SymEntry.getSectionID());
453 uint64_t TargetAddr = SectionAddr + SymEntry.getOffset();
454 return RuntimeDyld::SymbolInfo(TargetAddr, SymEntry.getFlags());
457 void resolveRelocations();
459 void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
461 void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress);
463 // Is the linker in an error state?
464 bool hasError() { return HasError; }
466 // Mark the error condition as handled and continue.
467 void clearError() { HasError = false; }
469 // Get the error message.
470 StringRef getErrorString() { return ErrorStr; }
472 virtual bool isCompatibleFile(const ObjectFile &Obj) const = 0;
474 virtual void registerEHFrames();
476 virtual void deregisterEHFrames();
478 virtual void finalizeLoad(const ObjectFile &ObjImg,
479 ObjSectionToIDMap &SectionMap) {}
482 } // end namespace llvm