1 //===-- RuntimeDyld.cpp - 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 // Implementation of the MC-JIT runtime dynamic linker. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #define DEBUG_TYPE "dyld" 15 #include "llvm/ExecutionEngine/RuntimeDyld.h" 16 #include "ObjectImageCommon.h" 17 #include "RuntimeDyldELF.h" 18 #include "RuntimeDyldImpl.h" 19 #include "RuntimeDyldMachO.h" 20 #include "llvm/Support/MathExtras.h" 21 #include "llvm/Support/Path.h" 22 23 using namespace llvm; 24 using namespace llvm::object; 25 26 // Empty out-of-line virtual destructor as the key function. 27 RTDyldMemoryManager::~RTDyldMemoryManager() {} 28 RuntimeDyldImpl::~RuntimeDyldImpl() {} 29 30 namespace llvm { 31 32 // Resolve the relocations for all symbols we currently know about. 33 void RuntimeDyldImpl::resolveRelocations() { 34 // First, resolve relocations associated with external symbols. 35 resolveExternalSymbols(); 36 37 // Just iterate over the sections we have and resolve all the relocations 38 // in them. Gross overkill, but it gets the job done. 39 for (int i = 0, e = Sections.size(); i != e; ++i) { 40 uint64_t Addr = Sections[i].LoadAddress; 41 DEBUG(dbgs() << "Resolving relocations Section #" << i 42 << "\t" << format("%p", (uint8_t *)Addr) 43 << "\n"); 44 resolveRelocationList(Relocations[i], Addr); 45 } 46 } 47 48 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress, 49 uint64_t TargetAddress) { 50 for (unsigned i = 0, e = Sections.size(); i != e; ++i) { 51 if (Sections[i].Address == LocalAddress) { 52 reassignSectionAddress(i, TargetAddress); 53 return; 54 } 55 } 56 llvm_unreachable("Attempting to remap address of unknown section!"); 57 } 58 59 // Subclasses can implement this method to create specialized image instances. 60 // The caller owns the pointer that is returned. 61 ObjectImage *RuntimeDyldImpl::createObjectImage(ObjectBuffer *InputBuffer) { 62 return new ObjectImageCommon(InputBuffer); 63 } 64 65 ObjectImage *RuntimeDyldImpl::loadObject(ObjectBuffer *InputBuffer) { 66 OwningPtr<ObjectImage> obj(createObjectImage(InputBuffer)); 67 if (!obj) 68 report_fatal_error("Unable to create object image from memory buffer!"); 69 70 Arch = (Triple::ArchType)obj->getArch(); 71 72 // Symbols found in this object 73 StringMap<SymbolLoc> LocalSymbols; 74 // Used sections from the object file 75 ObjSectionToIDMap LocalSections; 76 77 // Common symbols requiring allocation, with their sizes and alignments 78 CommonSymbolMap CommonSymbols; 79 // Maximum required total memory to allocate all common symbols 80 uint64_t CommonSize = 0; 81 82 error_code err; 83 // Parse symbols 84 DEBUG(dbgs() << "Parse symbols:\n"); 85 for (symbol_iterator i = obj->begin_symbols(), e = obj->end_symbols(); 86 i != e; i.increment(err)) { 87 Check(err); 88 object::SymbolRef::Type SymType; 89 StringRef Name; 90 Check(i->getType(SymType)); 91 Check(i->getName(Name)); 92 93 uint32_t flags; 94 Check(i->getFlags(flags)); 95 96 bool isCommon = flags & SymbolRef::SF_Common; 97 if (isCommon) { 98 // Add the common symbols to a list. We'll allocate them all below. 99 uint64_t Align = getCommonSymbolAlignment(*i); 100 uint64_t Size = 0; 101 Check(i->getSize(Size)); 102 CommonSize += Size + Align; 103 CommonSymbols[*i] = CommonSymbolInfo(Size, Align); 104 } else { 105 if (SymType == object::SymbolRef::ST_Function || 106 SymType == object::SymbolRef::ST_Data || 107 SymType == object::SymbolRef::ST_Unknown) { 108 uint64_t FileOffset; 109 StringRef SectionData; 110 bool IsCode; 111 section_iterator si = obj->end_sections(); 112 Check(i->getFileOffset(FileOffset)); 113 Check(i->getSection(si)); 114 if (si == obj->end_sections()) continue; 115 Check(si->getContents(SectionData)); 116 Check(si->isText(IsCode)); 117 const uint8_t* SymPtr = (const uint8_t*)InputBuffer->getBufferStart() + 118 (uintptr_t)FileOffset; 119 uintptr_t SectOffset = (uintptr_t)(SymPtr - 120 (const uint8_t*)SectionData.begin()); 121 unsigned SectionID = findOrEmitSection(*obj, *si, IsCode, LocalSections); 122 LocalSymbols[Name.data()] = SymbolLoc(SectionID, SectOffset); 123 DEBUG(dbgs() << "\tFileOffset: " << format("%p", (uintptr_t)FileOffset) 124 << " flags: " << flags 125 << " SID: " << SectionID 126 << " Offset: " << format("%p", SectOffset)); 127 GlobalSymbolTable[Name] = SymbolLoc(SectionID, SectOffset); 128 } 129 } 130 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n"); 131 } 132 133 // Allocate common symbols 134 if (CommonSize != 0) 135 emitCommonSymbols(*obj, CommonSymbols, CommonSize, LocalSymbols); 136 137 // Parse and process relocations 138 DEBUG(dbgs() << "Parse relocations:\n"); 139 for (section_iterator si = obj->begin_sections(), 140 se = obj->end_sections(); si != se; si.increment(err)) { 141 Check(err); 142 bool isFirstRelocation = true; 143 unsigned SectionID = 0; 144 StubMap Stubs; 145 146 for (relocation_iterator i = si->begin_relocations(), 147 e = si->end_relocations(); i != e; i.increment(err)) { 148 Check(err); 149 150 // If it's the first relocation in this section, find its SectionID 151 if (isFirstRelocation) { 152 SectionID = findOrEmitSection(*obj, *si, true, LocalSections); 153 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n"); 154 isFirstRelocation = false; 155 } 156 157 ObjRelocationInfo RI; 158 RI.SectionID = SectionID; 159 Check(i->getAdditionalInfo(RI.AdditionalInfo)); 160 Check(i->getOffset(RI.Offset)); 161 Check(i->getSymbol(RI.Symbol)); 162 Check(i->getType(RI.Type)); 163 164 DEBUG(dbgs() << "\t\tAddend: " << RI.AdditionalInfo 165 << " Offset: " << format("%p", (uintptr_t)RI.Offset) 166 << " Type: " << (uint32_t)(RI.Type & 0xffffffffL) 167 << "\n"); 168 processRelocationRef(RI, *obj, LocalSections, LocalSymbols, Stubs); 169 } 170 } 171 172 return obj.take(); 173 } 174 175 void RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj, 176 const CommonSymbolMap &CommonSymbols, 177 uint64_t TotalSize, 178 SymbolTableMap &SymbolTable) { 179 // Allocate memory for the section 180 unsigned SectionID = Sections.size(); 181 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void*), 182 SectionID, false); 183 if (!Addr) 184 report_fatal_error("Unable to allocate memory for common symbols!"); 185 uint64_t Offset = 0; 186 Sections.push_back(SectionEntry(StringRef(), Addr, TotalSize, TotalSize, 0)); 187 memset(Addr, 0, TotalSize); 188 189 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID 190 << " new addr: " << format("%p", Addr) 191 << " DataSize: " << TotalSize 192 << "\n"); 193 194 // Assign the address of each symbol 195 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(), 196 itEnd = CommonSymbols.end(); it != itEnd; it++) { 197 uint64_t Size = it->second.first; 198 uint64_t Align = it->second.second; 199 StringRef Name; 200 it->first.getName(Name); 201 if (Align) { 202 // This symbol has an alignment requirement. 203 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align); 204 Addr += AlignOffset; 205 Offset += AlignOffset; 206 DEBUG(dbgs() << "Allocating common symbol " << Name << " address " << 207 format("%p\n", Addr)); 208 } 209 Obj.updateSymbolAddress(it->first, (uint64_t)Addr); 210 SymbolTable[Name.data()] = SymbolLoc(SectionID, Offset); 211 Offset += Size; 212 Addr += Size; 213 } 214 } 215 216 unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj, 217 const SectionRef &Section, 218 bool IsCode) { 219 220 unsigned StubBufSize = 0, 221 StubSize = getMaxStubSize(); 222 error_code err; 223 if (StubSize > 0) { 224 for (relocation_iterator i = Section.begin_relocations(), 225 e = Section.end_relocations(); i != e; i.increment(err), Check(err)) 226 StubBufSize += StubSize; 227 } 228 StringRef data; 229 uint64_t Alignment64; 230 Check(Section.getContents(data)); 231 Check(Section.getAlignment(Alignment64)); 232 233 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL; 234 bool IsRequired; 235 bool IsVirtual; 236 bool IsZeroInit; 237 bool IsReadOnly; 238 uint64_t DataSize; 239 StringRef Name; 240 Check(Section.isRequiredForExecution(IsRequired)); 241 Check(Section.isVirtual(IsVirtual)); 242 Check(Section.isZeroInit(IsZeroInit)); 243 Check(Section.isReadOnlyData(IsReadOnly)); 244 Check(Section.getSize(DataSize)); 245 Check(Section.getName(Name)); 246 247 unsigned Allocate; 248 unsigned SectionID = Sections.size(); 249 uint8_t *Addr; 250 const char *pData = 0; 251 252 // Some sections, such as debug info, don't need to be loaded for execution. 253 // Leave those where they are. 254 if (IsRequired) { 255 Allocate = DataSize + StubBufSize; 256 Addr = IsCode 257 ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID) 258 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID, IsReadOnly); 259 if (!Addr) 260 report_fatal_error("Unable to allocate section memory!"); 261 262 // Virtual sections have no data in the object image, so leave pData = 0 263 if (!IsVirtual) 264 pData = data.data(); 265 266 // Zero-initialize or copy the data from the image 267 if (IsZeroInit || IsVirtual) 268 memset(Addr, 0, DataSize); 269 else 270 memcpy(Addr, pData, DataSize); 271 272 DEBUG(dbgs() << "emitSection SectionID: " << SectionID 273 << " Name: " << Name 274 << " obj addr: " << format("%p", pData) 275 << " new addr: " << format("%p", Addr) 276 << " DataSize: " << DataSize 277 << " StubBufSize: " << StubBufSize 278 << " Allocate: " << Allocate 279 << "\n"); 280 Obj.updateSectionAddress(Section, (uint64_t)Addr); 281 } 282 else { 283 // Even if we didn't load the section, we need to record an entry for it 284 // to handle later processing (and by 'handle' I mean don't do anything 285 // with these sections). 286 Allocate = 0; 287 Addr = 0; 288 DEBUG(dbgs() << "emitSection SectionID: " << SectionID 289 << " Name: " << Name 290 << " obj addr: " << format("%p", data.data()) 291 << " new addr: 0" 292 << " DataSize: " << DataSize 293 << " StubBufSize: " << StubBufSize 294 << " Allocate: " << Allocate 295 << "\n"); 296 } 297 298 Sections.push_back(SectionEntry(Name, Addr, Allocate, DataSize, 299 (uintptr_t)pData)); 300 return SectionID; 301 } 302 303 unsigned RuntimeDyldImpl::findOrEmitSection(ObjectImage &Obj, 304 const SectionRef &Section, 305 bool IsCode, 306 ObjSectionToIDMap &LocalSections) { 307 308 unsigned SectionID = 0; 309 ObjSectionToIDMap::iterator i = LocalSections.find(Section); 310 if (i != LocalSections.end()) 311 SectionID = i->second; 312 else { 313 SectionID = emitSection(Obj, Section, IsCode); 314 LocalSections[Section] = SectionID; 315 } 316 return SectionID; 317 } 318 319 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE, 320 unsigned SectionID) { 321 Relocations[SectionID].push_back(RE); 322 } 323 324 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE, 325 StringRef SymbolName) { 326 // Relocation by symbol. If the symbol is found in the global symbol table, 327 // create an appropriate section relocation. Otherwise, add it to 328 // ExternalSymbolRelocations. 329 SymbolTableMap::const_iterator Loc = 330 GlobalSymbolTable.find(SymbolName); 331 if (Loc == GlobalSymbolTable.end()) { 332 ExternalSymbolRelocations[SymbolName].push_back(RE); 333 } else { 334 // Copy the RE since we want to modify its addend. 335 RelocationEntry RECopy = RE; 336 RECopy.Addend += Loc->second.second; 337 Relocations[Loc->second.first].push_back(RECopy); 338 } 339 } 340 341 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr) { 342 if (Arch == Triple::arm) { 343 // TODO: There is only ARM far stub now. We should add the Thumb stub, 344 // and stubs for branches Thumb - ARM and ARM - Thumb. 345 uint32_t *StubAddr = (uint32_t*)Addr; 346 *StubAddr = 0xe51ff004; // ldr pc,<label> 347 return (uint8_t*)++StubAddr; 348 } else if (Arch == Triple::mipsel || Arch == Triple::mips) { 349 uint32_t *StubAddr = (uint32_t*)Addr; 350 // 0: 3c190000 lui t9,%hi(addr). 351 // 4: 27390000 addiu t9,t9,%lo(addr). 352 // 8: 03200008 jr t9. 353 // c: 00000000 nop. 354 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000; 355 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0; 356 357 *StubAddr = LuiT9Instr; 358 StubAddr++; 359 *StubAddr = AdduiT9Instr; 360 StubAddr++; 361 *StubAddr = JrT9Instr; 362 StubAddr++; 363 *StubAddr = NopInstr; 364 return Addr; 365 } else if (Arch == Triple::ppc64) { 366 // PowerPC64 stub: the address points to a function descriptor 367 // instead of the function itself. Load the function address 368 // on r11 and sets it to control register. Also loads the function 369 // TOC in r2 and environment pointer to r11. 370 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr) 371 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr) 372 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32 373 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr) 374 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr) 375 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1) 376 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12) 377 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12) 378 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11 379 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2) 380 writeInt32BE(Addr+40, 0x4E800420); // bctr 381 382 return Addr; 383 } 384 return Addr; 385 } 386 387 // Assign an address to a symbol name and resolve all the relocations 388 // associated with it. 389 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID, 390 uint64_t Addr) { 391 // The address to use for relocation resolution is not 392 // the address of the local section buffer. We must be doing 393 // a remote execution environment of some sort. Relocations can't 394 // be applied until all the sections have been moved. The client must 395 // trigger this with a call to MCJIT::finalize() or 396 // RuntimeDyld::resolveRelocations(). 397 // 398 // Addr is a uint64_t because we can't assume the pointer width 399 // of the target is the same as that of the host. Just use a generic 400 // "big enough" type. 401 Sections[SectionID].LoadAddress = Addr; 402 } 403 404 void RuntimeDyldImpl::resolveRelocationEntry(const RelocationEntry &RE, 405 uint64_t Value) { 406 // Ignore relocations for sections that were not loaded 407 if (Sections[RE.SectionID].Address != 0) { 408 DEBUG(dbgs() << "\tSectionID: " << RE.SectionID 409 << " + " << RE.Offset << " (" 410 << format("%p", Sections[RE.SectionID].Address + RE.Offset) << ")" 411 << " RelType: " << RE.RelType 412 << " Addend: " << RE.Addend 413 << "\n"); 414 415 resolveRelocation(Sections[RE.SectionID], RE.Offset, 416 Value, RE.RelType, RE.Addend); 417 } 418 } 419 420 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs, 421 uint64_t Value) { 422 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) { 423 resolveRelocationEntry(Relocs[i], Value); 424 } 425 } 426 427 void RuntimeDyldImpl::resolveExternalSymbols() { 428 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin(), 429 e = ExternalSymbolRelocations.end(); 430 for (; i != e; i++) { 431 StringRef Name = i->first(); 432 RelocationList &Relocs = i->second; 433 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name); 434 if (Loc == GlobalSymbolTable.end()) { 435 if (Name.size() == 0) { 436 // This is an absolute symbol, use an address of zero. 437 DEBUG(dbgs() << "Resolving absolute relocations." << "\n"); 438 resolveRelocationList(Relocs, 0); 439 } else { 440 // This is an external symbol, try to get its address from 441 // MemoryManager. 442 uint8_t *Addr = (uint8_t*) MemMgr->getPointerToNamedFunction(Name.data(), 443 true); 444 DEBUG(dbgs() << "Resolving relocations Name: " << Name 445 << "\t" << format("%p", Addr) 446 << "\n"); 447 resolveRelocationList(Relocs, (uintptr_t)Addr); 448 } 449 } else { 450 report_fatal_error("Expected external symbol"); 451 } 452 } 453 } 454 455 456 //===----------------------------------------------------------------------===// 457 // RuntimeDyld class implementation 458 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) { 459 // FIXME: There's a potential issue lurking here if a single instance of 460 // RuntimeDyld is used to load multiple objects. The current implementation 461 // associates a single memory manager with a RuntimeDyld instance. Even 462 // though the public class spawns a new 'impl' instance for each load, 463 // they share a single memory manager. This can become a problem when page 464 // permissions are applied. 465 Dyld = 0; 466 MM = mm; 467 } 468 469 RuntimeDyld::~RuntimeDyld() { 470 delete Dyld; 471 } 472 473 ObjectImage *RuntimeDyld::loadObject(ObjectBuffer *InputBuffer) { 474 if (!Dyld) { 475 sys::LLVMFileType type = sys::IdentifyFileType( 476 InputBuffer->getBufferStart(), 477 static_cast<unsigned>(InputBuffer->getBufferSize())); 478 switch (type) { 479 case sys::ELF_Relocatable_FileType: 480 case sys::ELF_Executable_FileType: 481 case sys::ELF_SharedObject_FileType: 482 case sys::ELF_Core_FileType: 483 Dyld = new RuntimeDyldELF(MM); 484 break; 485 case sys::Mach_O_Object_FileType: 486 case sys::Mach_O_Executable_FileType: 487 case sys::Mach_O_FixedVirtualMemorySharedLib_FileType: 488 case sys::Mach_O_Core_FileType: 489 case sys::Mach_O_PreloadExecutable_FileType: 490 case sys::Mach_O_DynamicallyLinkedSharedLib_FileType: 491 case sys::Mach_O_DynamicLinker_FileType: 492 case sys::Mach_O_Bundle_FileType: 493 case sys::Mach_O_DynamicallyLinkedSharedLibStub_FileType: 494 case sys::Mach_O_DSYMCompanion_FileType: 495 Dyld = new RuntimeDyldMachO(MM); 496 break; 497 case sys::Unknown_FileType: 498 case sys::Bitcode_FileType: 499 case sys::Archive_FileType: 500 case sys::COFF_FileType: 501 report_fatal_error("Incompatible object format!"); 502 } 503 } else { 504 if (!Dyld->isCompatibleFormat(InputBuffer)) 505 report_fatal_error("Incompatible object format!"); 506 } 507 508 return Dyld->loadObject(InputBuffer); 509 } 510 511 void *RuntimeDyld::getSymbolAddress(StringRef Name) { 512 return Dyld->getSymbolAddress(Name); 513 } 514 515 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) { 516 return Dyld->getSymbolLoadAddress(Name); 517 } 518 519 void RuntimeDyld::resolveRelocations() { 520 Dyld->resolveRelocations(); 521 } 522 523 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, 524 uint64_t Addr) { 525 Dyld->reassignSectionAddress(SectionID, Addr); 526 } 527 528 void RuntimeDyld::mapSectionAddress(const void *LocalAddress, 529 uint64_t TargetAddress) { 530 Dyld->mapSectionAddress(LocalAddress, TargetAddress); 531 } 532 533 StringRef RuntimeDyld::getErrorString() { 534 return Dyld->getErrorString(); 535 } 536 537 } // end namespace llvm 538
