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RuntimeDyldELF.cpp
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1 //===-- RuntimeDyldELF.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 ELF support for the MC-JIT runtime dynamic linker.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "RuntimeDyldELF.h"
15 #include "RuntimeDyldCheckerImpl.h"
17 #include "llvm/ADT/IntervalMap.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/BinaryFormat/ELF.h"
22 #include "llvm/MC/MCStreamer.h"
24 #include "llvm/Object/ObjectFile.h"
25 #include "llvm/Support/Endian.h"
27 
28 using namespace llvm;
29 using namespace llvm::object;
30 using namespace llvm::support::endian;
31 
32 #define DEBUG_TYPE "dyld"
33 
34 static void or32le(void *P, int32_t V) { write32le(P, read32le(P) | V); }
35 
36 static void or32AArch64Imm(void *L, uint64_t Imm) {
37  or32le(L, (Imm & 0xFFF) << 10);
38 }
39 
40 template <class T> static void write(bool isBE, void *P, T V) {
41  isBE ? write<T, support::big>(P, V) : write<T, support::little>(P, V);
42 }
43 
44 static void write32AArch64Addr(void *L, uint64_t Imm) {
45  uint32_t ImmLo = (Imm & 0x3) << 29;
46  uint32_t ImmHi = (Imm & 0x1FFFFC) << 3;
47  uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3);
48  write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi);
49 }
50 
51 // Return the bits [Start, End] from Val shifted Start bits.
52 // For instance, getBits(0xF0, 4, 8) returns 0xF.
53 static uint64_t getBits(uint64_t Val, int Start, int End) {
54  uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1;
55  return (Val >> Start) & Mask;
56 }
57 
58 namespace {
59 
60 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> {
62 
63  typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
64  typedef Elf_Sym_Impl<ELFT> Elf_Sym;
65  typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
66  typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
67 
68  typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
69 
70  typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type;
71 
72  DyldELFObject(ELFObjectFile<ELFT> &&Obj);
73 
74 public:
76  create(MemoryBufferRef Wrapper);
77 
78  void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
79 
80  void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr);
81 
82  // Methods for type inquiry through isa, cast and dyn_cast
83  static bool classof(const Binary *v) {
84  return (isa<ELFObjectFile<ELFT>>(v) &&
85  classof(cast<ELFObjectFile<ELFT>>(v)));
86  }
87  static bool classof(const ELFObjectFile<ELFT> *v) {
88  return v->isDyldType();
89  }
90 };
91 
92 
93 
94 // The MemoryBuffer passed into this constructor is just a wrapper around the
95 // actual memory. Ultimately, the Binary parent class will take ownership of
96 // this MemoryBuffer object but not the underlying memory.
97 template <class ELFT>
98 DyldELFObject<ELFT>::DyldELFObject(ELFObjectFile<ELFT> &&Obj)
99  : ELFObjectFile<ELFT>(std::move(Obj)) {
100  this->isDyldELFObject = true;
101 }
102 
103 template <class ELFT>
105 DyldELFObject<ELFT>::create(MemoryBufferRef Wrapper) {
106  auto Obj = ELFObjectFile<ELFT>::create(Wrapper);
107  if (auto E = Obj.takeError())
108  return std::move(E);
109  std::unique_ptr<DyldELFObject<ELFT>> Ret(
110  new DyldELFObject<ELFT>(std::move(*Obj)));
111  return std::move(Ret);
112 }
113 
114 template <class ELFT>
115 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
116  uint64_t Addr) {
117  DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
118  Elf_Shdr *shdr =
119  const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
120 
121  // This assumes the address passed in matches the target address bitness
122  // The template-based type cast handles everything else.
123  shdr->sh_addr = static_cast<addr_type>(Addr);
124 }
125 
126 template <class ELFT>
127 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
128  uint64_t Addr) {
129 
130  Elf_Sym *sym = const_cast<Elf_Sym *>(
132 
133  // This assumes the address passed in matches the target address bitness
134  // The template-based type cast handles everything else.
135  sym->st_value = static_cast<addr_type>(Addr);
136 }
137 
138 class LoadedELFObjectInfo final
139  : public LoadedObjectInfoHelper<LoadedELFObjectInfo,
140  RuntimeDyld::LoadedObjectInfo> {
141 public:
142  LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
143  : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
144 
146  getObjectForDebug(const ObjectFile &Obj) const override;
147 };
148 
149 template <typename ELFT>
151 createRTDyldELFObject(MemoryBufferRef Buffer, const ObjectFile &SourceObject,
152  const LoadedELFObjectInfo &L) {
153  typedef typename ELFFile<ELFT>::Elf_Shdr Elf_Shdr;
154  typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type;
155 
157  DyldELFObject<ELFT>::create(Buffer);
158  if (Error E = ObjOrErr.takeError())
159  return std::move(E);
160 
161  std::unique_ptr<DyldELFObject<ELFT>> Obj = std::move(*ObjOrErr);
162 
163  // Iterate over all sections in the object.
164  auto SI = SourceObject.section_begin();
165  for (const auto &Sec : Obj->sections()) {
167  Sec.getName(SectionName);
168  if (SectionName != "") {
169  DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
170  Elf_Shdr *shdr = const_cast<Elf_Shdr *>(
171  reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
172 
173  if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) {
174  // This assumes that the address passed in matches the target address
175  // bitness. The template-based type cast handles everything else.
176  shdr->sh_addr = static_cast<addr_type>(SecLoadAddr);
177  }
178  }
179  ++SI;
180  }
181 
182  return std::move(Obj);
183 }
184 
186 createELFDebugObject(const ObjectFile &Obj, const LoadedELFObjectInfo &L) {
187  assert(Obj.isELF() && "Not an ELF object file.");
188 
189  std::unique_ptr<MemoryBuffer> Buffer =
191 
192  Expected<std::unique_ptr<ObjectFile>> DebugObj(nullptr);
193  handleAllErrors(DebugObj.takeError());
194  if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian())
195  DebugObj =
196  createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L);
197  else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian())
198  DebugObj =
199  createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L);
200  else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian())
201  DebugObj =
202  createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L);
203  else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian())
204  DebugObj =
205  createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L);
206  else
207  llvm_unreachable("Unexpected ELF format");
208 
209  handleAllErrors(DebugObj.takeError());
210  return OwningBinary<ObjectFile>(std::move(*DebugObj), std::move(Buffer));
211 }
212 
214 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const {
215  return createELFDebugObject(Obj, *this);
216 }
217 
218 } // anonymous namespace
219 
220 namespace llvm {
221 
223  JITSymbolResolver &Resolver)
224  : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {}
226 
228  for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
229  SID EHFrameSID = UnregisteredEHFrameSections[i];
230  uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
231  uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
232  size_t EHFrameSize = Sections[EHFrameSID].getSize();
233  MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
234  }
235  UnregisteredEHFrameSections.clear();
236 }
237 
238 std::unique_ptr<RuntimeDyldELF>
242  switch (Arch) {
243  default:
244  return make_unique<RuntimeDyldELF>(MemMgr, Resolver);
245  case Triple::mips:
246  case Triple::mipsel:
247  case Triple::mips64:
248  case Triple::mips64el:
249  return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver);
250  }
251 }
252 
253 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
255  if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
256  return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr);
257  else {
258  HasError = true;
259  raw_string_ostream ErrStream(ErrorStr);
260  logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, "");
261  return nullptr;
262  }
263 }
264 
265 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
266  uint64_t Offset, uint64_t Value,
267  uint32_t Type, int64_t Addend,
268  uint64_t SymOffset) {
269  switch (Type) {
270  default:
271  llvm_unreachable("Relocation type not implemented yet!");
272  break;
273  case ELF::R_X86_64_NONE:
274  break;
275  case ELF::R_X86_64_64: {
277  Value + Addend;
278  DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
279  << format("%p\n", Section.getAddressWithOffset(Offset)));
280  break;
281  }
282  case ELF::R_X86_64_32:
283  case ELF::R_X86_64_32S: {
284  Value += Addend;
285  assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) ||
286  (Type == ELF::R_X86_64_32S &&
287  ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN)));
288  uint32_t TruncatedAddr = (Value & 0xFFFFFFFF);
290  TruncatedAddr;
291  DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at "
292  << format("%p\n", Section.getAddressWithOffset(Offset)));
293  break;
294  }
295  case ELF::R_X86_64_PC8: {
296  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
297  int64_t RealOffset = Value + Addend - FinalAddress;
298  assert(isInt<8>(RealOffset));
299  int8_t TruncOffset = (RealOffset & 0xFF);
300  Section.getAddress()[Offset] = TruncOffset;
301  break;
302  }
303  case ELF::R_X86_64_PC32: {
304  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
305  int64_t RealOffset = Value + Addend - FinalAddress;
306  assert(isInt<32>(RealOffset));
307  int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
309  TruncOffset;
310  break;
311  }
312  case ELF::R_X86_64_PC64: {
313  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
314  int64_t RealOffset = Value + Addend - FinalAddress;
316  RealOffset;
317  break;
318  }
319  }
320 }
321 
322 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
323  uint64_t Offset, uint32_t Value,
324  uint32_t Type, int32_t Addend) {
325  switch (Type) {
326  case ELF::R_386_32: {
328  Value + Addend;
329  break;
330  }
331  case ELF::R_386_PC32: {
332  uint32_t FinalAddress =
333  Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
334  uint32_t RealOffset = Value + Addend - FinalAddress;
336  RealOffset;
337  break;
338  }
339  default:
340  // There are other relocation types, but it appears these are the
341  // only ones currently used by the LLVM ELF object writer
342  llvm_unreachable("Relocation type not implemented yet!");
343  break;
344  }
345 }
346 
347 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
348  uint64_t Offset, uint64_t Value,
349  uint32_t Type, int64_t Addend) {
350  uint32_t *TargetPtr =
351  reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
352  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
353  // Data should use target endian. Code should always use little endian.
354  bool isBE = Arch == Triple::aarch64_be;
355 
356  DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
357  << format("%llx", Section.getAddressWithOffset(Offset))
358  << " FinalAddress: 0x" << format("%llx", FinalAddress)
359  << " Value: 0x" << format("%llx", Value) << " Type: 0x"
360  << format("%x", Type) << " Addend: 0x" << format("%llx", Addend)
361  << "\n");
362 
363  switch (Type) {
364  default:
365  llvm_unreachable("Relocation type not implemented yet!");
366  break;
367  case ELF::R_AARCH64_ABS16: {
368  uint64_t Result = Value + Addend;
369  assert(static_cast<int64_t>(Result) >= INT16_MIN && Result < UINT16_MAX);
370  write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU));
371  break;
372  }
373  case ELF::R_AARCH64_ABS32: {
374  uint64_t Result = Value + Addend;
375  assert(static_cast<int64_t>(Result) >= INT32_MIN && Result < UINT32_MAX);
376  write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU));
377  break;
378  }
379  case ELF::R_AARCH64_ABS64:
380  write(isBE, TargetPtr, Value + Addend);
381  break;
382  case ELF::R_AARCH64_PREL32: {
383  uint64_t Result = Value + Addend - FinalAddress;
384  assert(static_cast<int64_t>(Result) >= INT32_MIN &&
385  static_cast<int64_t>(Result) <= UINT32_MAX);
386  write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU));
387  break;
388  }
389  case ELF::R_AARCH64_PREL64:
390  write(isBE, TargetPtr, Value + Addend - FinalAddress);
391  break;
392  case ELF::R_AARCH64_CALL26: // fallthrough
393  case ELF::R_AARCH64_JUMP26: {
394  // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
395  // calculation.
396  uint64_t BranchImm = Value + Addend - FinalAddress;
397 
398  // "Check that -2^27 <= result < 2^27".
399  assert(isInt<28>(BranchImm));
400  or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2);
401  break;
402  }
403  case ELF::R_AARCH64_MOVW_UABS_G3:
404  or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43);
405  break;
406  case ELF::R_AARCH64_MOVW_UABS_G2_NC:
407  or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27);
408  break;
409  case ELF::R_AARCH64_MOVW_UABS_G1_NC:
410  or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11);
411  break;
412  case ELF::R_AARCH64_MOVW_UABS_G0_NC:
413  or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5);
414  break;
415  case ELF::R_AARCH64_ADR_PREL_PG_HI21: {
416  // Operation: Page(S+A) - Page(P)
417  uint64_t Result =
418  ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL);
419 
420  // Check that -2^32 <= X < 2^32
421  assert(isInt<33>(Result) && "overflow check failed for relocation");
422 
423  // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken
424  // from bits 32:12 of X.
425  write32AArch64Addr(TargetPtr, Result >> 12);
426  break;
427  }
428  case ELF::R_AARCH64_ADD_ABS_LO12_NC:
429  // Operation: S + A
430  // Immediate goes in bits 21:10 of LD/ST instruction, taken
431  // from bits 11:0 of X
432  or32AArch64Imm(TargetPtr, Value + Addend);
433  break;
434  case ELF::R_AARCH64_LDST8_ABS_LO12_NC:
435  // Operation: S + A
436  // Immediate goes in bits 21:10 of LD/ST instruction, taken
437  // from bits 11:0 of X
438  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11));
439  break;
440  case ELF::R_AARCH64_LDST16_ABS_LO12_NC:
441  // Operation: S + A
442  // Immediate goes in bits 21:10 of LD/ST instruction, taken
443  // from bits 11:1 of X
444  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11));
445  break;
446  case ELF::R_AARCH64_LDST32_ABS_LO12_NC:
447  // Operation: S + A
448  // Immediate goes in bits 21:10 of LD/ST instruction, taken
449  // from bits 11:2 of X
450  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11));
451  break;
452  case ELF::R_AARCH64_LDST64_ABS_LO12_NC:
453  // Operation: S + A
454  // Immediate goes in bits 21:10 of LD/ST instruction, taken
455  // from bits 11:3 of X
456  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11));
457  break;
458  case ELF::R_AARCH64_LDST128_ABS_LO12_NC:
459  // Operation: S + A
460  // Immediate goes in bits 21:10 of LD/ST instruction, taken
461  // from bits 11:4 of X
462  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11));
463  break;
464  }
465 }
466 
467 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
468  uint64_t Offset, uint32_t Value,
469  uint32_t Type, int32_t Addend) {
470  // TODO: Add Thumb relocations.
471  uint32_t *TargetPtr =
472  reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
473  uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
474  Value += Addend;
475 
476  DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
477  << Section.getAddressWithOffset(Offset)
478  << " FinalAddress: " << format("%p", FinalAddress) << " Value: "
479  << format("%x", Value) << " Type: " << format("%x", Type)
480  << " Addend: " << format("%x", Addend) << "\n");
481 
482  switch (Type) {
483  default:
484  llvm_unreachable("Not implemented relocation type!");
485 
486  case ELF::R_ARM_NONE:
487  break;
488  // Write a 31bit signed offset
489  case ELF::R_ARM_PREL31:
490  support::ulittle32_t::ref{TargetPtr} =
491  (support::ulittle32_t::ref{TargetPtr} & 0x80000000) |
492  ((Value - FinalAddress) & ~0x80000000);
493  break;
494  case ELF::R_ARM_TARGET1:
495  case ELF::R_ARM_ABS32:
496  support::ulittle32_t::ref{TargetPtr} = Value;
497  break;
498  // Write first 16 bit of 32 bit value to the mov instruction.
499  // Last 4 bit should be shifted.
500  case ELF::R_ARM_MOVW_ABS_NC:
501  case ELF::R_ARM_MOVT_ABS:
502  if (Type == ELF::R_ARM_MOVW_ABS_NC)
503  Value = Value & 0xFFFF;
504  else if (Type == ELF::R_ARM_MOVT_ABS)
505  Value = (Value >> 16) & 0xFFFF;
506  support::ulittle32_t::ref{TargetPtr} =
507  (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) |
508  (((Value >> 12) & 0xF) << 16);
509  break;
510  // Write 24 bit relative value to the branch instruction.
511  case ELF::R_ARM_PC24: // Fall through.
512  case ELF::R_ARM_CALL: // Fall through.
513  case ELF::R_ARM_JUMP24:
514  int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
515  RelValue = (RelValue & 0x03FFFFFC) >> 2;
516  assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE);
517  support::ulittle32_t::ref{TargetPtr} =
518  (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue;
519  break;
520  }
521 }
522 
523 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) {
524  if (Arch == Triple::UnknownArch ||
525  !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) {
526  IsMipsO32ABI = false;
527  IsMipsN32ABI = false;
528  IsMipsN64ABI = false;
529  return;
530  }
531  unsigned AbiVariant;
532  Obj.getPlatformFlags(AbiVariant);
533  IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32;
534  IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2;
535  IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips");
536 }
537 
538 // Return the .TOC. section and offset.
539 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj,
540  ObjSectionToIDMap &LocalSections,
541  RelocationValueRef &Rel) {
542  // Set a default SectionID in case we do not find a TOC section below.
543  // This may happen for references to TOC base base (sym@toc, .odp
544  // relocation) without a .toc directive. In this case just use the
545  // first section (which is usually the .odp) since the code won't
546  // reference the .toc base directly.
547  Rel.SymbolName = nullptr;
548  Rel.SectionID = 0;
549 
550  // The TOC consists of sections .got, .toc, .tocbss, .plt in that
551  // order. The TOC starts where the first of these sections starts.
552  for (auto &Section: Obj.sections()) {
554  if (auto EC = Section.getName(SectionName))
555  return errorCodeToError(EC);
556 
557  if (SectionName == ".got"
558  || SectionName == ".toc"
559  || SectionName == ".tocbss"
560  || SectionName == ".plt") {
561  if (auto SectionIDOrErr =
562  findOrEmitSection(Obj, Section, false, LocalSections))
563  Rel.SectionID = *SectionIDOrErr;
564  else
565  return SectionIDOrErr.takeError();
566  break;
567  }
568  }
569 
570  // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
571  // thus permitting a full 64 Kbytes segment.
572  Rel.Addend = 0x8000;
573 
574  return Error::success();
575 }
576 
577 // Returns the sections and offset associated with the ODP entry referenced
578 // by Symbol.
579 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj,
580  ObjSectionToIDMap &LocalSections,
581  RelocationValueRef &Rel) {
582  // Get the ELF symbol value (st_value) to compare with Relocation offset in
583  // .opd entries
584  for (section_iterator si = Obj.section_begin(), se = Obj.section_end();
585  si != se; ++si) {
586  section_iterator RelSecI = si->getRelocatedSection();
587  if (RelSecI == Obj.section_end())
588  continue;
589 
590  StringRef RelSectionName;
591  if (auto EC = RelSecI->getName(RelSectionName))
592  return errorCodeToError(EC);
593 
594  if (RelSectionName != ".opd")
595  continue;
596 
597  for (elf_relocation_iterator i = si->relocation_begin(),
598  e = si->relocation_end();
599  i != e;) {
600  // The R_PPC64_ADDR64 relocation indicates the first field
601  // of a .opd entry
602  uint64_t TypeFunc = i->getType();
603  if (TypeFunc != ELF::R_PPC64_ADDR64) {
604  ++i;
605  continue;
606  }
607 
608  uint64_t TargetSymbolOffset = i->getOffset();
609  symbol_iterator TargetSymbol = i->getSymbol();
610  int64_t Addend;
611  if (auto AddendOrErr = i->getAddend())
612  Addend = *AddendOrErr;
613  else
614  return AddendOrErr.takeError();
615 
616  ++i;
617  if (i == e)
618  break;
619 
620  // Just check if following relocation is a R_PPC64_TOC
621  uint64_t TypeTOC = i->getType();
622  if (TypeTOC != ELF::R_PPC64_TOC)
623  continue;
624 
625  // Finally compares the Symbol value and the target symbol offset
626  // to check if this .opd entry refers to the symbol the relocation
627  // points to.
628  if (Rel.Addend != (int64_t)TargetSymbolOffset)
629  continue;
630 
631  section_iterator TSI = Obj.section_end();
632  if (auto TSIOrErr = TargetSymbol->getSection())
633  TSI = *TSIOrErr;
634  else
635  return TSIOrErr.takeError();
636  assert(TSI != Obj.section_end() && "TSI should refer to a valid section");
637 
638  bool IsCode = TSI->isText();
639  if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode,
640  LocalSections))
641  Rel.SectionID = *SectionIDOrErr;
642  else
643  return SectionIDOrErr.takeError();
644  Rel.Addend = (intptr_t)Addend;
645  return Error::success();
646  }
647  }
648  llvm_unreachable("Attempting to get address of ODP entry!");
649 }
650 
651 // Relocation masks following the #lo(value), #hi(value), #ha(value),
652 // #higher(value), #highera(value), #highest(value), and #highesta(value)
653 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi
654 // document.
655 
656 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; }
657 
658 static inline uint16_t applyPPChi(uint64_t value) {
659  return (value >> 16) & 0xffff;
660 }
661 
662 static inline uint16_t applyPPCha (uint64_t value) {
663  return ((value + 0x8000) >> 16) & 0xffff;
664 }
665 
666 static inline uint16_t applyPPChigher(uint64_t value) {
667  return (value >> 32) & 0xffff;
668 }
669 
670 static inline uint16_t applyPPChighera (uint64_t value) {
671  return ((value + 0x8000) >> 32) & 0xffff;
672 }
673 
674 static inline uint16_t applyPPChighest(uint64_t value) {
675  return (value >> 48) & 0xffff;
676 }
677 
678 static inline uint16_t applyPPChighesta (uint64_t value) {
679  return ((value + 0x8000) >> 48) & 0xffff;
680 }
681 
682 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section,
683  uint64_t Offset, uint64_t Value,
684  uint32_t Type, int64_t Addend) {
685  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
686  switch (Type) {
687  default:
688  llvm_unreachable("Relocation type not implemented yet!");
689  break;
690  case ELF::R_PPC_ADDR16_LO:
691  writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
692  break;
693  case ELF::R_PPC_ADDR16_HI:
694  writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
695  break;
696  case ELF::R_PPC_ADDR16_HA:
697  writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
698  break;
699  }
700 }
701 
702 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
703  uint64_t Offset, uint64_t Value,
704  uint32_t Type, int64_t Addend) {
705  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
706  switch (Type) {
707  default:
708  llvm_unreachable("Relocation type not implemented yet!");
709  break;
710  case ELF::R_PPC64_ADDR16:
711  writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
712  break;
713  case ELF::R_PPC64_ADDR16_DS:
714  writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
715  break;
716  case ELF::R_PPC64_ADDR16_LO:
717  writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
718  break;
719  case ELF::R_PPC64_ADDR16_LO_DS:
720  writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
721  break;
722  case ELF::R_PPC64_ADDR16_HI:
723  writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
724  break;
725  case ELF::R_PPC64_ADDR16_HA:
726  writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
727  break;
728  case ELF::R_PPC64_ADDR16_HIGHER:
729  writeInt16BE(LocalAddress, applyPPChigher(Value + Addend));
730  break;
731  case ELF::R_PPC64_ADDR16_HIGHERA:
732  writeInt16BE(LocalAddress, applyPPChighera(Value + Addend));
733  break;
734  case ELF::R_PPC64_ADDR16_HIGHEST:
735  writeInt16BE(LocalAddress, applyPPChighest(Value + Addend));
736  break;
737  case ELF::R_PPC64_ADDR16_HIGHESTA:
738  writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend));
739  break;
740  case ELF::R_PPC64_ADDR14: {
741  assert(((Value + Addend) & 3) == 0);
742  // Preserve the AA/LK bits in the branch instruction
743  uint8_t aalk = *(LocalAddress + 3);
744  writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
745  } break;
746  case ELF::R_PPC64_REL16_LO: {
747  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
748  uint64_t Delta = Value - FinalAddress + Addend;
749  writeInt16BE(LocalAddress, applyPPClo(Delta));
750  } break;
751  case ELF::R_PPC64_REL16_HI: {
752  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
753  uint64_t Delta = Value - FinalAddress + Addend;
754  writeInt16BE(LocalAddress, applyPPChi(Delta));
755  } break;
756  case ELF::R_PPC64_REL16_HA: {
757  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
758  uint64_t Delta = Value - FinalAddress + Addend;
759  writeInt16BE(LocalAddress, applyPPCha(Delta));
760  } break;
761  case ELF::R_PPC64_ADDR32: {
762  int64_t Result = static_cast<int64_t>(Value + Addend);
763  if (SignExtend64<32>(Result) != Result)
764  llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
765  writeInt32BE(LocalAddress, Result);
766  } break;
767  case ELF::R_PPC64_REL24: {
768  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
769  int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend);
770  if (SignExtend64<26>(delta) != delta)
771  llvm_unreachable("Relocation R_PPC64_REL24 overflow");
772  // Generates a 'bl <address>' instruction
773  writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
774  } break;
775  case ELF::R_PPC64_REL32: {
776  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
777  int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend);
778  if (SignExtend64<32>(delta) != delta)
779  llvm_unreachable("Relocation R_PPC64_REL32 overflow");
780  writeInt32BE(LocalAddress, delta);
781  } break;
782  case ELF::R_PPC64_REL64: {
783  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
784  uint64_t Delta = Value - FinalAddress + Addend;
785  writeInt64BE(LocalAddress, Delta);
786  } break;
787  case ELF::R_PPC64_ADDR64:
788  writeInt64BE(LocalAddress, Value + Addend);
789  break;
790  }
791 }
792 
793 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
794  uint64_t Offset, uint64_t Value,
795  uint32_t Type, int64_t Addend) {
796  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
797  switch (Type) {
798  default:
799  llvm_unreachable("Relocation type not implemented yet!");
800  break;
801  case ELF::R_390_PC16DBL:
802  case ELF::R_390_PLT16DBL: {
803  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
804  assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
805  writeInt16BE(LocalAddress, Delta / 2);
806  break;
807  }
808  case ELF::R_390_PC32DBL:
809  case ELF::R_390_PLT32DBL: {
810  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
811  assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
812  writeInt32BE(LocalAddress, Delta / 2);
813  break;
814  }
815  case ELF::R_390_PC16: {
816  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
817  assert(int16_t(Delta) == Delta && "R_390_PC16 overflow");
818  writeInt16BE(LocalAddress, Delta);
819  break;
820  }
821  case ELF::R_390_PC32: {
822  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
823  assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
824  writeInt32BE(LocalAddress, Delta);
825  break;
826  }
827  case ELF::R_390_PC64: {
828  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
829  writeInt64BE(LocalAddress, Delta);
830  break;
831  }
832  case ELF::R_390_8:
833  *LocalAddress = (uint8_t)(Value + Addend);
834  break;
835  case ELF::R_390_16:
836  writeInt16BE(LocalAddress, Value + Addend);
837  break;
838  case ELF::R_390_32:
839  writeInt32BE(LocalAddress, Value + Addend);
840  break;
841  case ELF::R_390_64:
842  writeInt64BE(LocalAddress, Value + Addend);
843  break;
844  }
845 }
846 
847 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section,
848  uint64_t Offset, uint64_t Value,
849  uint32_t Type, int64_t Addend) {
850  bool isBE = Arch == Triple::bpfeb;
851 
852  switch (Type) {
853  default:
854  llvm_unreachable("Relocation type not implemented yet!");
855  break;
856  case ELF::R_BPF_NONE:
857  break;
858  case ELF::R_BPF_64_64: {
859  write(isBE, Section.getAddressWithOffset(Offset), Value + Addend);
860  DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
861  << format("%p\n", Section.getAddressWithOffset(Offset)));
862  break;
863  }
864  case ELF::R_BPF_64_32: {
865  Value += Addend;
866  assert(Value <= UINT32_MAX);
867  write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value));
868  DEBUG(dbgs() << "Writing " << format("%p", Value) << " at "
869  << format("%p\n", Section.getAddressWithOffset(Offset)));
870  break;
871  }
872  }
873 }
874 
875 // The target location for the relocation is described by RE.SectionID and
876 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
877 // SectionEntry has three members describing its location.
878 // SectionEntry::Address is the address at which the section has been loaded
879 // into memory in the current (host) process. SectionEntry::LoadAddress is the
880 // address that the section will have in the target process.
881 // SectionEntry::ObjAddress is the address of the bits for this section in the
882 // original emitted object image (also in the current address space).
883 //
884 // Relocations will be applied as if the section were loaded at
885 // SectionEntry::LoadAddress, but they will be applied at an address based
886 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to
887 // Target memory contents if they are required for value calculations.
888 //
889 // The Value parameter here is the load address of the symbol for the
890 // relocation to be applied. For relocations which refer to symbols in the
891 // current object Value will be the LoadAddress of the section in which
892 // the symbol resides (RE.Addend provides additional information about the
893 // symbol location). For external symbols, Value will be the address of the
894 // symbol in the target address space.
895 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
896  uint64_t Value) {
897  const SectionEntry &Section = Sections[RE.SectionID];
898  return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
899  RE.SymOffset, RE.SectionID);
900 }
901 
902 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
903  uint64_t Offset, uint64_t Value,
904  uint32_t Type, int64_t Addend,
905  uint64_t SymOffset, SID SectionID) {
906  switch (Arch) {
907  case Triple::x86_64:
908  resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset);
909  break;
910  case Triple::x86:
911  resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
912  (uint32_t)(Addend & 0xffffffffL));
913  break;
914  case Triple::aarch64:
915  case Triple::aarch64_be:
916  resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
917  break;
918  case Triple::arm: // Fall through.
919  case Triple::armeb:
920  case Triple::thumb:
921  case Triple::thumbeb:
922  resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
923  (uint32_t)(Addend & 0xffffffffL));
924  break;
925  case Triple::ppc:
926  resolvePPC32Relocation(Section, Offset, Value, Type, Addend);
927  break;
928  case Triple::ppc64: // Fall through.
929  case Triple::ppc64le:
930  resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
931  break;
932  case Triple::systemz:
933  resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
934  break;
935  case Triple::bpfel:
936  case Triple::bpfeb:
937  resolveBPFRelocation(Section, Offset, Value, Type, Addend);
938  break;
939  default:
940  llvm_unreachable("Unsupported CPU type!");
941  }
942 }
943 
944 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const {
945  return (void *)(Sections[SectionID].getObjAddress() + Offset);
946 }
947 
948 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) {
949  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
950  if (Value.SymbolName)
952  else
954 }
955 
956 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType,
957  bool IsLocal) const {
958  switch (RelType) {
959  case ELF::R_MICROMIPS_GOT16:
960  if (IsLocal)
961  return ELF::R_MICROMIPS_LO16;
962  break;
963  case ELF::R_MICROMIPS_HI16:
964  return ELF::R_MICROMIPS_LO16;
965  case ELF::R_MIPS_GOT16:
966  if (IsLocal)
967  return ELF::R_MIPS_LO16;
968  break;
969  case ELF::R_MIPS_HI16:
970  return ELF::R_MIPS_LO16;
971  case ELF::R_MIPS_PCHI16:
972  return ELF::R_MIPS_PCLO16;
973  default:
974  break;
975  }
976  return ELF::R_MIPS_NONE;
977 }
978 
979 // Sometimes we don't need to create thunk for a branch.
980 // This typically happens when branch target is located
981 // in the same object file. In such case target is either
982 // a weak symbol or symbol in a different executable section.
983 // This function checks if branch target is located in the
984 // same object file and if distance between source and target
985 // fits R_AARCH64_CALL26 relocation. If both conditions are
986 // met, it emits direct jump to the target and returns true.
987 // Otherwise false is returned and thunk is created.
988 bool RuntimeDyldELF::resolveAArch64ShortBranch(
989  unsigned SectionID, relocation_iterator RelI,
990  const RelocationValueRef &Value) {
991  uint64_t Address;
992  if (Value.SymbolName) {
993  auto Loc = GlobalSymbolTable.find(Value.SymbolName);
994 
995  // Don't create direct branch for external symbols.
996  if (Loc == GlobalSymbolTable.end())
997  return false;
998 
999  const auto &SymInfo = Loc->second;
1000  Address =
1001  uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset(
1002  SymInfo.getOffset()));
1003  } else {
1004  Address = uint64_t(Sections[Value.SectionID].getLoadAddress());
1005  }
1006  uint64_t Offset = RelI->getOffset();
1007  uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset);
1008 
1009  // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27
1010  // If distance between source and target is out of range then we should
1011  // create thunk.
1012  if (!isInt<28>(Address + Value.Addend - SourceAddress))
1013  return false;
1014 
1015  resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(),
1016  Value.Addend);
1017 
1018  return true;
1019 }
1020 
1021 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID,
1022  const RelocationValueRef &Value,
1023  relocation_iterator RelI,
1024  StubMap &Stubs) {
1025 
1026  DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
1027  SectionEntry &Section = Sections[SectionID];
1028 
1029  uint64_t Offset = RelI->getOffset();
1030  unsigned RelType = RelI->getType();
1031  // Look for an existing stub.
1032  StubMap::const_iterator i = Stubs.find(Value);
1033  if (i != Stubs.end()) {
1034  resolveRelocation(Section, Offset,
1035  (uint64_t)Section.getAddressWithOffset(i->second),
1036  RelType, 0);
1037  DEBUG(dbgs() << " Stub function found\n");
1038  } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) {
1039  // Create a new stub function.
1040  DEBUG(dbgs() << " Create a new stub function\n");
1041  Stubs[Value] = Section.getStubOffset();
1042  uint8_t *StubTargetAddr = createStubFunction(
1043  Section.getAddressWithOffset(Section.getStubOffset()));
1044 
1045  RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(),
1046  ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
1047  RelocationEntry REmovk_g2(SectionID,
1048  StubTargetAddr - Section.getAddress() + 4,
1049  ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
1050  RelocationEntry REmovk_g1(SectionID,
1051  StubTargetAddr - Section.getAddress() + 8,
1052  ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
1053  RelocationEntry REmovk_g0(SectionID,
1054  StubTargetAddr - Section.getAddress() + 12,
1055  ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
1056 
1057  if (Value.SymbolName) {
1058  addRelocationForSymbol(REmovz_g3, Value.SymbolName);
1059  addRelocationForSymbol(REmovk_g2, Value.SymbolName);
1060  addRelocationForSymbol(REmovk_g1, Value.SymbolName);
1061  addRelocationForSymbol(REmovk_g0, Value.SymbolName);
1062  } else {
1063  addRelocationForSection(REmovz_g3, Value.SectionID);
1064  addRelocationForSection(REmovk_g2, Value.SectionID);
1065  addRelocationForSection(REmovk_g1, Value.SectionID);
1066  addRelocationForSection(REmovk_g0, Value.SectionID);
1067  }
1068  resolveRelocation(Section, Offset,
1069  reinterpret_cast<uint64_t>(Section.getAddressWithOffset(
1070  Section.getStubOffset())),
1071  RelType, 0);
1072  Section.advanceStubOffset(getMaxStubSize());
1073  }
1074 }
1075 
1078  unsigned SectionID, relocation_iterator RelI, const ObjectFile &O,
1079  ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) {
1080  const auto &Obj = cast<ELFObjectFileBase>(O);
1081  uint64_t RelType = RelI->getType();
1082  int64_t Addend = 0;
1083  if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend())
1084  Addend = *AddendOrErr;
1085  else
1086  consumeError(AddendOrErr.takeError());
1087  elf_symbol_iterator Symbol = RelI->getSymbol();
1088 
1089  // Obtain the symbol name which is referenced in the relocation
1090  StringRef TargetName;
1091  if (Symbol != Obj.symbol_end()) {
1092  if (auto TargetNameOrErr = Symbol->getName())
1093  TargetName = *TargetNameOrErr;
1094  else
1095  return TargetNameOrErr.takeError();
1096  }
1097  DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend
1098  << " TargetName: " << TargetName << "\n");
1099  RelocationValueRef Value;
1100  // First search for the symbol in the local symbol table
1101  SymbolRef::Type SymType = SymbolRef::ST_Unknown;
1102 
1103  // Search for the symbol in the global symbol table
1105  if (Symbol != Obj.symbol_end()) {
1106  gsi = GlobalSymbolTable.find(TargetName.data());
1107  Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType();
1108  if (!SymTypeOrErr) {
1109  std::string Buf;
1110  raw_string_ostream OS(Buf);
1111  logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, "");
1112  OS.flush();
1113  report_fatal_error(Buf);
1114  }
1115  SymType = *SymTypeOrErr;
1116  }
1117  if (gsi != GlobalSymbolTable.end()) {
1118  const auto &SymInfo = gsi->second;
1119  Value.SectionID = SymInfo.getSectionID();
1120  Value.Offset = SymInfo.getOffset();
1121  Value.Addend = SymInfo.getOffset() + Addend;
1122  } else {
1123  switch (SymType) {
1124  case SymbolRef::ST_Debug: {
1125  // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
1126  // and can be changed by another developers. Maybe best way is add
1127  // a new symbol type ST_Section to SymbolRef and use it.
1128  auto SectionOrErr = Symbol->getSection();
1129  if (!SectionOrErr) {
1130  std::string Buf;
1131  raw_string_ostream OS(Buf);
1132  logAllUnhandledErrors(SectionOrErr.takeError(), OS, "");
1133  OS.flush();
1134  report_fatal_error(Buf);
1135  }
1136  section_iterator si = *SectionOrErr;
1137  if (si == Obj.section_end())
1138  llvm_unreachable("Symbol section not found, bad object file format!");
1139  DEBUG(dbgs() << "\t\tThis is section symbol\n");
1140  bool isCode = si->isText();
1141  if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode,
1142  ObjSectionToID))
1143  Value.SectionID = *SectionIDOrErr;
1144  else
1145  return SectionIDOrErr.takeError();
1146  Value.Addend = Addend;
1147  break;
1148  }
1149  case SymbolRef::ST_Data:
1150  case SymbolRef::ST_Function:
1151  case SymbolRef::ST_Unknown: {
1152  Value.SymbolName = TargetName.data();
1153  Value.Addend = Addend;
1154 
1155  // Absolute relocations will have a zero symbol ID (STN_UNDEF), which
1156  // will manifest here as a NULL symbol name.
1157  // We can set this as a valid (but empty) symbol name, and rely
1158  // on addRelocationForSymbol to handle this.
1159  if (!Value.SymbolName)
1160  Value.SymbolName = "";
1161  break;
1162  }
1163  default:
1164  llvm_unreachable("Unresolved symbol type!");
1165  break;
1166  }
1167  }
1168 
1169  uint64_t Offset = RelI->getOffset();
1170 
1171  DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset
1172  << "\n");
1173  if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) {
1174  if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) {
1175  resolveAArch64Branch(SectionID, Value, RelI, Stubs);
1176  } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) {
1177  // Craete new GOT entry or find existing one. If GOT entry is
1178  // to be created, then we also emit ABS64 relocation for it.
1179  uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64);
1180  resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1181  ELF::R_AARCH64_ADR_PREL_PG_HI21);
1182 
1183  } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) {
1184  uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64);
1185  resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1186  ELF::R_AARCH64_LDST64_ABS_LO12_NC);
1187  } else {
1188  processSimpleRelocation(SectionID, Offset, RelType, Value);
1189  }
1190  } else if (Arch == Triple::arm) {
1191  if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL ||
1192  RelType == ELF::R_ARM_JUMP24) {
1193  // This is an ARM branch relocation, need to use a stub function.
1194  DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n");
1195  SectionEntry &Section = Sections[SectionID];
1196 
1197  // Look for an existing stub.
1198  StubMap::const_iterator i = Stubs.find(Value);
1199  if (i != Stubs.end()) {
1200  resolveRelocation(
1201  Section, Offset,
1202  reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)),
1203  RelType, 0);
1204  DEBUG(dbgs() << " Stub function found\n");
1205  } else {
1206  // Create a new stub function.
1207  DEBUG(dbgs() << " Create a new stub function\n");
1208  Stubs[Value] = Section.getStubOffset();
1209  uint8_t *StubTargetAddr = createStubFunction(
1210  Section.getAddressWithOffset(Section.getStubOffset()));
1211  RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1212  ELF::R_ARM_ABS32, Value.Addend);
1213  if (Value.SymbolName)
1215  else
1217 
1218  resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1219  Section.getAddressWithOffset(
1220  Section.getStubOffset())),
1221  RelType, 0);
1222  Section.advanceStubOffset(getMaxStubSize());
1223  }
1224  } else {
1225  uint32_t *Placeholder =
1226  reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset));
1227  if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 ||
1228  RelType == ELF::R_ARM_ABS32) {
1229  Value.Addend += *Placeholder;
1230  } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) {
1231  // See ELF for ARM documentation
1232  Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12));
1233  }
1234  processSimpleRelocation(SectionID, Offset, RelType, Value);
1235  }
1236  } else if (IsMipsO32ABI) {
1237  uint8_t *Placeholder = reinterpret_cast<uint8_t *>(
1238  computePlaceholderAddress(SectionID, Offset));
1239  uint32_t Opcode = readBytesUnaligned(Placeholder, 4);
1240  if (RelType == ELF::R_MIPS_26) {
1241  // This is an Mips branch relocation, need to use a stub function.
1242  DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1243  SectionEntry &Section = Sections[SectionID];
1244 
1245  // Extract the addend from the instruction.
1246  // We shift up by two since the Value will be down shifted again
1247  // when applying the relocation.
1248  uint32_t Addend = (Opcode & 0x03ffffff) << 2;
1249 
1250  Value.Addend += Addend;
1251 
1252  // Look up for existing stub.
1253  StubMap::const_iterator i = Stubs.find(Value);
1254  if (i != Stubs.end()) {
1255  RelocationEntry RE(SectionID, Offset, RelType, i->second);
1256  addRelocationForSection(RE, SectionID);
1257  DEBUG(dbgs() << " Stub function found\n");
1258  } else {
1259  // Create a new stub function.
1260  DEBUG(dbgs() << " Create a new stub function\n");
1261  Stubs[Value] = Section.getStubOffset();
1262 
1263  unsigned AbiVariant;
1264  O.getPlatformFlags(AbiVariant);
1265 
1266  uint8_t *StubTargetAddr = createStubFunction(
1267  Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
1268 
1269  // Creating Hi and Lo relocations for the filled stub instructions.
1270  RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
1271  ELF::R_MIPS_HI16, Value.Addend);
1272  RelocationEntry RELo(SectionID,
1273  StubTargetAddr - Section.getAddress() + 4,
1274  ELF::R_MIPS_LO16, Value.Addend);
1275 
1276  if (Value.SymbolName) {
1277  addRelocationForSymbol(REHi, Value.SymbolName);
1278  addRelocationForSymbol(RELo, Value.SymbolName);
1279  } else {
1280  addRelocationForSection(REHi, Value.SectionID);
1281  addRelocationForSection(RELo, Value.SectionID);
1282  }
1283 
1284  RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
1285  addRelocationForSection(RE, SectionID);
1286  Section.advanceStubOffset(getMaxStubSize());
1287  }
1288  } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) {
1289  int64_t Addend = (Opcode & 0x0000ffff) << 16;
1290  RelocationEntry RE(SectionID, Offset, RelType, Addend);
1291  PendingRelocs.push_back(std::make_pair(Value, RE));
1292  } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) {
1293  int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff);
1294  for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) {
1295  const RelocationValueRef &MatchingValue = I->first;
1296  RelocationEntry &Reloc = I->second;
1297  if (MatchingValue == Value &&
1298  RelType == getMatchingLoRelocation(Reloc.RelType) &&
1299  SectionID == Reloc.SectionID) {
1300  Reloc.Addend += Addend;
1301  if (Value.SymbolName)
1302  addRelocationForSymbol(Reloc, Value.SymbolName);
1303  else
1304  addRelocationForSection(Reloc, Value.SectionID);
1305  I = PendingRelocs.erase(I);
1306  } else
1307  ++I;
1308  }
1309  RelocationEntry RE(SectionID, Offset, RelType, Addend);
1310  if (Value.SymbolName)
1312  else
1314  } else {
1315  if (RelType == ELF::R_MIPS_32)
1316  Value.Addend += Opcode;
1317  else if (RelType == ELF::R_MIPS_PC16)
1318  Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2);
1319  else if (RelType == ELF::R_MIPS_PC19_S2)
1320  Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2);
1321  else if (RelType == ELF::R_MIPS_PC21_S2)
1322  Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2);
1323  else if (RelType == ELF::R_MIPS_PC26_S2)
1324  Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2);
1325  processSimpleRelocation(SectionID, Offset, RelType, Value);
1326  }
1327  } else if (IsMipsN32ABI || IsMipsN64ABI) {
1328  uint32_t r_type = RelType & 0xff;
1329  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1330  if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE
1331  || r_type == ELF::R_MIPS_GOT_DISP) {
1332  StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName);
1333  if (i != GOTSymbolOffsets.end())
1334  RE.SymOffset = i->second;
1335  else {
1336  RE.SymOffset = allocateGOTEntries(1);
1337  GOTSymbolOffsets[TargetName] = RE.SymOffset;
1338  }
1339  if (Value.SymbolName)
1341  else
1343  } else if (RelType == ELF::R_MIPS_26) {
1344  // This is an Mips branch relocation, need to use a stub function.
1345  DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1346  SectionEntry &Section = Sections[SectionID];
1347 
1348  // Look up for existing stub.
1349  StubMap::const_iterator i = Stubs.find(Value);
1350  if (i != Stubs.end()) {
1351  RelocationEntry RE(SectionID, Offset, RelType, i->second);
1352  addRelocationForSection(RE, SectionID);
1353  DEBUG(dbgs() << " Stub function found\n");
1354  } else {
1355  // Create a new stub function.
1356  DEBUG(dbgs() << " Create a new stub function\n");
1357  Stubs[Value] = Section.getStubOffset();
1358 
1359  unsigned AbiVariant;
1360  O.getPlatformFlags(AbiVariant);
1361 
1362  uint8_t *StubTargetAddr = createStubFunction(
1363  Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
1364 
1365  if (IsMipsN32ABI) {
1366  // Creating Hi and Lo relocations for the filled stub instructions.
1367  RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
1368  ELF::R_MIPS_HI16, Value.Addend);
1369  RelocationEntry RELo(SectionID,
1370  StubTargetAddr - Section.getAddress() + 4,
1371  ELF::R_MIPS_LO16, Value.Addend);
1372  if (Value.SymbolName) {
1373  addRelocationForSymbol(REHi, Value.SymbolName);
1374  addRelocationForSymbol(RELo, Value.SymbolName);
1375  } else {
1376  addRelocationForSection(REHi, Value.SectionID);
1377  addRelocationForSection(RELo, Value.SectionID);
1378  }
1379  } else {
1380  // Creating Highest, Higher, Hi and Lo relocations for the filled stub
1381  // instructions.
1382  RelocationEntry REHighest(SectionID,
1383  StubTargetAddr - Section.getAddress(),
1384  ELF::R_MIPS_HIGHEST, Value.Addend);
1385  RelocationEntry REHigher(SectionID,
1386  StubTargetAddr - Section.getAddress() + 4,
1387  ELF::R_MIPS_HIGHER, Value.Addend);
1388  RelocationEntry REHi(SectionID,
1389  StubTargetAddr - Section.getAddress() + 12,
1390  ELF::R_MIPS_HI16, Value.Addend);
1391  RelocationEntry RELo(SectionID,
1392  StubTargetAddr - Section.getAddress() + 20,
1393  ELF::R_MIPS_LO16, Value.Addend);
1394  if (Value.SymbolName) {
1395  addRelocationForSymbol(REHighest, Value.SymbolName);
1396  addRelocationForSymbol(REHigher, Value.SymbolName);
1397  addRelocationForSymbol(REHi, Value.SymbolName);
1398  addRelocationForSymbol(RELo, Value.SymbolName);
1399  } else {
1400  addRelocationForSection(REHighest, Value.SectionID);
1401  addRelocationForSection(REHigher, Value.SectionID);
1402  addRelocationForSection(REHi, Value.SectionID);
1403  addRelocationForSection(RELo, Value.SectionID);
1404  }
1405  }
1406  RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
1407  addRelocationForSection(RE, SectionID);
1408  Section.advanceStubOffset(getMaxStubSize());
1409  }
1410  } else {
1411  processSimpleRelocation(SectionID, Offset, RelType, Value);
1412  }
1413 
1414  } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1415  if (RelType == ELF::R_PPC64_REL24) {
1416  // Determine ABI variant in use for this object.
1417  unsigned AbiVariant;
1418  Obj.getPlatformFlags(AbiVariant);
1419  AbiVariant &= ELF::EF_PPC64_ABI;
1420  // A PPC branch relocation will need a stub function if the target is
1421  // an external symbol (either Value.SymbolName is set, or SymType is
1422  // Symbol::ST_Unknown) or if the target address is not within the
1423  // signed 24-bits branch address.
1424  SectionEntry &Section = Sections[SectionID];
1425  uint8_t *Target = Section.getAddressWithOffset(Offset);
1426  bool RangeOverflow = false;
1427  if (!Value.SymbolName && SymType != SymbolRef::ST_Unknown) {
1428  if (AbiVariant != 2) {
1429  // In the ELFv1 ABI, a function call may point to the .opd entry,
1430  // so the final symbol value is calculated based on the relocation
1431  // values in the .opd section.
1432  if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value))
1433  return std::move(Err);
1434  } else {
1435  // In the ELFv2 ABI, a function symbol may provide a local entry
1436  // point, which must be used for direct calls.
1437  uint8_t SymOther = Symbol->getOther();
1438  Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther);
1439  }
1440  uint8_t *RelocTarget =
1441  Sections[Value.SectionID].getAddressWithOffset(Value.Addend);
1442  int64_t delta = static_cast<int64_t>(Target - RelocTarget);
1443  // If it is within 26-bits branch range, just set the branch target
1444  if (SignExtend64<26>(delta) == delta) {
1445  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1447  } else {
1448  RangeOverflow = true;
1449  }
1450  }
1451  if (Value.SymbolName || SymType == SymbolRef::ST_Unknown ||
1452  RangeOverflow) {
1453  // It is an external symbol (either Value.SymbolName is set, or
1454  // SymType is SymbolRef::ST_Unknown) or out of range.
1455  StubMap::const_iterator i = Stubs.find(Value);
1456  if (i != Stubs.end()) {
1457  // Symbol function stub already created, just relocate to it
1458  resolveRelocation(Section, Offset,
1459  reinterpret_cast<uint64_t>(
1460  Section.getAddressWithOffset(i->second)),
1461  RelType, 0);
1462  DEBUG(dbgs() << " Stub function found\n");
1463  } else {
1464  // Create a new stub function.
1465  DEBUG(dbgs() << " Create a new stub function\n");
1466  Stubs[Value] = Section.getStubOffset();
1467  uint8_t *StubTargetAddr = createStubFunction(
1468  Section.getAddressWithOffset(Section.getStubOffset()),
1469  AbiVariant);
1470  RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1471  ELF::R_PPC64_ADDR64, Value.Addend);
1472 
1473  // Generates the 64-bits address loads as exemplified in section
1474  // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to
1475  // apply to the low part of the instructions, so we have to update
1476  // the offset according to the target endianness.
1477  uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress();
1478  if (!IsTargetLittleEndian)
1479  StubRelocOffset += 2;
1480 
1481  RelocationEntry REhst(SectionID, StubRelocOffset + 0,
1482  ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
1483  RelocationEntry REhr(SectionID, StubRelocOffset + 4,
1484  ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
1485  RelocationEntry REh(SectionID, StubRelocOffset + 12,
1486  ELF::R_PPC64_ADDR16_HI, Value.Addend);
1487  RelocationEntry REl(SectionID, StubRelocOffset + 16,
1488  ELF::R_PPC64_ADDR16_LO, Value.Addend);
1489 
1490  if (Value.SymbolName) {
1491  addRelocationForSymbol(REhst, Value.SymbolName);
1492  addRelocationForSymbol(REhr, Value.SymbolName);
1493  addRelocationForSymbol(REh, Value.SymbolName);
1494  addRelocationForSymbol(REl, Value.SymbolName);
1495  } else {
1496  addRelocationForSection(REhst, Value.SectionID);
1497  addRelocationForSection(REhr, Value.SectionID);
1498  addRelocationForSection(REh, Value.SectionID);
1499  addRelocationForSection(REl, Value.SectionID);
1500  }
1501 
1502  resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1503  Section.getAddressWithOffset(
1504  Section.getStubOffset())),
1505  RelType, 0);
1506  Section.advanceStubOffset(getMaxStubSize());
1507  }
1508  if (Value.SymbolName || SymType == SymbolRef::ST_Unknown) {
1509  // Restore the TOC for external calls
1510  if (AbiVariant == 2)
1511  writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1)
1512  else
1513  writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1)
1514  }
1515  }
1516  } else if (RelType == ELF::R_PPC64_TOC16 ||
1517  RelType == ELF::R_PPC64_TOC16_DS ||
1518  RelType == ELF::R_PPC64_TOC16_LO ||
1519  RelType == ELF::R_PPC64_TOC16_LO_DS ||
1520  RelType == ELF::R_PPC64_TOC16_HI ||
1521  RelType == ELF::R_PPC64_TOC16_HA) {
1522  // These relocations are supposed to subtract the TOC address from
1523  // the final value. This does not fit cleanly into the RuntimeDyld
1524  // scheme, since there may be *two* sections involved in determining
1525  // the relocation value (the section of the symbol referred to by the
1526  // relocation, and the TOC section associated with the current module).
1527  //
1528  // Fortunately, these relocations are currently only ever generated
1529  // referring to symbols that themselves reside in the TOC, which means
1530  // that the two sections are actually the same. Thus they cancel out
1531  // and we can immediately resolve the relocation right now.
1532  switch (RelType) {
1533  case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break;
1534  case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break;
1535  case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break;
1536  case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break;
1537  case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break;
1538  case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break;
1539  default: llvm_unreachable("Wrong relocation type.");
1540  }
1541 
1542  RelocationValueRef TOCValue;
1543  if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue))
1544  return std::move(Err);
1545  if (Value.SymbolName || Value.SectionID != TOCValue.SectionID)
1546  llvm_unreachable("Unsupported TOC relocation.");
1547  Value.Addend -= TOCValue.Addend;
1548  resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0);
1549  } else {
1550  // There are two ways to refer to the TOC address directly: either
1551  // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are
1552  // ignored), or via any relocation that refers to the magic ".TOC."
1553  // symbols (in which case the addend is respected).
1554  if (RelType == ELF::R_PPC64_TOC) {
1555  RelType = ELF::R_PPC64_ADDR64;
1556  if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1557  return std::move(Err);
1558  } else if (TargetName == ".TOC.") {
1559  if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1560  return std::move(Err);
1561  Value.Addend += Addend;
1562  }
1563 
1564  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1565 
1566  if (Value.SymbolName)
1568  else
1570  }
1571  } else if (Arch == Triple::systemz &&
1572  (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) {
1573  // Create function stubs for both PLT and GOT references, regardless of
1574  // whether the GOT reference is to data or code. The stub contains the
1575  // full address of the symbol, as needed by GOT references, and the
1576  // executable part only adds an overhead of 8 bytes.
1577  //
1578  // We could try to conserve space by allocating the code and data
1579  // parts of the stub separately. However, as things stand, we allocate
1580  // a stub for every relocation, so using a GOT in JIT code should be
1581  // no less space efficient than using an explicit constant pool.
1582  DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1583  SectionEntry &Section = Sections[SectionID];
1584 
1585  // Look for an existing stub.
1586  StubMap::const_iterator i = Stubs.find(Value);
1587  uintptr_t StubAddress;
1588  if (i != Stubs.end()) {
1589  StubAddress = uintptr_t(Section.getAddressWithOffset(i->second));
1590  DEBUG(dbgs() << " Stub function found\n");
1591  } else {
1592  // Create a new stub function.
1593  DEBUG(dbgs() << " Create a new stub function\n");
1594 
1595  uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1596  uintptr_t StubAlignment = getStubAlignment();
1597  StubAddress =
1598  (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1599  -StubAlignment;
1600  unsigned StubOffset = StubAddress - BaseAddress;
1601 
1602  Stubs[Value] = StubOffset;
1603  createStubFunction((uint8_t *)StubAddress);
1604  RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64,
1605  Value.Offset);
1606  if (Value.SymbolName)
1608  else
1610  Section.advanceStubOffset(getMaxStubSize());
1611  }
1612 
1613  if (RelType == ELF::R_390_GOTENT)
1614  resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL,
1615  Addend);
1616  else
1617  resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1618  } else if (Arch == Triple::x86_64) {
1619  if (RelType == ELF::R_X86_64_PLT32) {
1620  // The way the PLT relocations normally work is that the linker allocates
1621  // the
1622  // PLT and this relocation makes a PC-relative call into the PLT. The PLT
1623  // entry will then jump to an address provided by the GOT. On first call,
1624  // the
1625  // GOT address will point back into PLT code that resolves the symbol. After
1626  // the first call, the GOT entry points to the actual function.
1627  //
1628  // For local functions we're ignoring all of that here and just replacing
1629  // the PLT32 relocation type with PC32, which will translate the relocation
1630  // into a PC-relative call directly to the function. For external symbols we
1631  // can't be sure the function will be within 2^32 bytes of the call site, so
1632  // we need to create a stub, which calls into the GOT. This case is
1633  // equivalent to the usual PLT implementation except that we use the stub
1634  // mechanism in RuntimeDyld (which puts stubs at the end of the section)
1635  // rather than allocating a PLT section.
1636  if (Value.SymbolName) {
1637  // This is a call to an external function.
1638  // Look for an existing stub.
1639  SectionEntry &Section = Sections[SectionID];
1640  StubMap::const_iterator i = Stubs.find(Value);
1641  uintptr_t StubAddress;
1642  if (i != Stubs.end()) {
1643  StubAddress = uintptr_t(Section.getAddress()) + i->second;
1644  DEBUG(dbgs() << " Stub function found\n");
1645  } else {
1646  // Create a new stub function (equivalent to a PLT entry).
1647  DEBUG(dbgs() << " Create a new stub function\n");
1648 
1649  uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1650  uintptr_t StubAlignment = getStubAlignment();
1651  StubAddress =
1652  (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1653  -StubAlignment;
1654  unsigned StubOffset = StubAddress - BaseAddress;
1655  Stubs[Value] = StubOffset;
1656  createStubFunction((uint8_t *)StubAddress);
1657 
1658  // Bump our stub offset counter
1659  Section.advanceStubOffset(getMaxStubSize());
1660 
1661  // Allocate a GOT Entry
1662  uint64_t GOTOffset = allocateGOTEntries(1);
1663 
1664  // The load of the GOT address has an addend of -4
1665  resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4,
1666  ELF::R_X86_64_PC32);
1667 
1668  // Fill in the value of the symbol we're targeting into the GOT
1670  computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64),
1671  Value.SymbolName);
1672  }
1673 
1674  // Make the target call a call into the stub table.
1675  resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32,
1676  Addend);
1677  } else {
1678  RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend,
1679  Value.Offset);
1681  }
1682  } else if (RelType == ELF::R_X86_64_GOTPCREL ||
1683  RelType == ELF::R_X86_64_GOTPCRELX ||
1684  RelType == ELF::R_X86_64_REX_GOTPCRELX) {
1685  uint64_t GOTOffset = allocateGOTEntries(1);
1686  resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1687  ELF::R_X86_64_PC32);
1688 
1689  // Fill in the value of the symbol we're targeting into the GOT
1690  RelocationEntry RE =
1691  computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64);
1692  if (Value.SymbolName)
1694  else
1696  } else if (RelType == ELF::R_X86_64_PC32) {
1697  Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1698  processSimpleRelocation(SectionID, Offset, RelType, Value);
1699  } else if (RelType == ELF::R_X86_64_PC64) {
1700  Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset));
1701  processSimpleRelocation(SectionID, Offset, RelType, Value);
1702  } else {
1703  processSimpleRelocation(SectionID, Offset, RelType, Value);
1704  }
1705  } else {
1706  if (Arch == Triple::x86) {
1707  Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1708  }
1709  processSimpleRelocation(SectionID, Offset, RelType, Value);
1710  }
1711  return ++RelI;
1712 }
1713 
1715  // We don't use the GOT in all of these cases, but it's essentially free
1716  // to put them all here.
1717  size_t Result = 0;
1718  switch (Arch) {
1719  case Triple::x86_64:
1720  case Triple::aarch64:
1721  case Triple::aarch64_be:
1722  case Triple::ppc64:
1723  case Triple::ppc64le:
1724  case Triple::systemz:
1725  Result = sizeof(uint64_t);
1726  break;
1727  case Triple::x86:
1728  case Triple::arm:
1729  case Triple::thumb:
1730  Result = sizeof(uint32_t);
1731  break;
1732  case Triple::mips:
1733  case Triple::mipsel:
1734  case Triple::mips64:
1735  case Triple::mips64el:
1736  if (IsMipsO32ABI || IsMipsN32ABI)
1737  Result = sizeof(uint32_t);
1738  else if (IsMipsN64ABI)
1739  Result = sizeof(uint64_t);
1740  else
1741  llvm_unreachable("Mips ABI not handled");
1742  break;
1743  default:
1744  llvm_unreachable("Unsupported CPU type!");
1745  }
1746  return Result;
1747 }
1748 
1749 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) {
1750  if (GOTSectionID == 0) {
1751  GOTSectionID = Sections.size();
1752  // Reserve a section id. We'll allocate the section later
1753  // once we know the total size
1754  Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0));
1755  }
1756  uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize();
1757  CurrentGOTIndex += no;
1758  return StartOffset;
1759 }
1760 
1761 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value,
1762  unsigned GOTRelType) {
1763  auto E = GOTOffsetMap.insert({Value, 0});
1764  if (E.second) {
1765  uint64_t GOTOffset = allocateGOTEntries(1);
1766 
1767  // Create relocation for newly created GOT entry
1768  RelocationEntry RE =
1769  computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType);
1770  if (Value.SymbolName)
1772  else
1774 
1775  E.first->second = GOTOffset;
1776  }
1777 
1778  return E.first->second;
1779 }
1780 
1781 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID,
1782  uint64_t Offset,
1783  uint64_t GOTOffset,
1784  uint32_t Type) {
1785  // Fill in the relative address of the GOT Entry into the stub
1786  RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset);
1787  addRelocationForSection(GOTRE, GOTSectionID);
1788 }
1789 
1790 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset,
1791  uint64_t SymbolOffset,
1792  uint32_t Type) {
1793  return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset);
1794 }
1795 
1797  ObjSectionToIDMap &SectionMap) {
1798  if (IsMipsO32ABI)
1799  if (!PendingRelocs.empty())
1800  return make_error<RuntimeDyldError>("Can't find matching LO16 reloc");
1801 
1802  // If necessary, allocate the global offset table
1803  if (GOTSectionID != 0) {
1804  // Allocate memory for the section
1805  size_t TotalSize = CurrentGOTIndex * getGOTEntrySize();
1806  uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(),
1807  GOTSectionID, ".got", false);
1808  if (!Addr)
1809  return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!");
1810 
1811  Sections[GOTSectionID] =
1812  SectionEntry(".got", Addr, TotalSize, TotalSize, 0);
1813 
1814  if (Checker)
1815  Checker->registerSection(Obj.getFileName(), GOTSectionID);
1816 
1817  // For now, initialize all GOT entries to zero. We'll fill them in as
1818  // needed when GOT-based relocations are applied.
1819  memset(Addr, 0, TotalSize);
1820  if (IsMipsN32ABI || IsMipsN64ABI) {
1821  // To correctly resolve Mips GOT relocations, we need a mapping from
1822  // object's sections to GOTs.
1823  for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
1824  SI != SE; ++SI) {
1825  if (SI->relocation_begin() != SI->relocation_end()) {
1826  section_iterator RelocatedSection = SI->getRelocatedSection();
1827  ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection);
1828  assert (i != SectionMap.end());
1829  SectionToGOTMap[i->second] = GOTSectionID;
1830  }
1831  }
1832  GOTSymbolOffsets.clear();
1833  }
1834  }
1835 
1836  // Look for and record the EH frame section.
1837  ObjSectionToIDMap::iterator i, e;
1838  for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
1839  const SectionRef &Section = i->first;
1840  StringRef Name;
1841  Section.getName(Name);
1842  if (Name == ".eh_frame") {
1843  UnregisteredEHFrameSections.push_back(i->second);
1844  break;
1845  }
1846  }
1847 
1848  GOTSectionID = 0;
1849  CurrentGOTIndex = 0;
1850 
1851  return Error::success();
1852 }
1853 
1855  return Obj.isELF();
1856 }
1857 
1858 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const {
1859  unsigned RelTy = R.getType();
1861  return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE ||
1862  RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC;
1863 
1864  if (Arch == Triple::x86_64)
1865  return RelTy == ELF::R_X86_64_GOTPCREL ||
1866  RelTy == ELF::R_X86_64_GOTPCRELX ||
1867  RelTy == ELF::R_X86_64_REX_GOTPCRELX;
1868  return false;
1869 }
1870 
1871 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const {
1872  if (Arch != Triple::x86_64)
1873  return true; // Conservative answer
1874 
1875  switch (R.getType()) {
1876  default:
1877  return true; // Conservative answer
1878 
1879 
1880  case ELF::R_X86_64_GOTPCREL:
1881  case ELF::R_X86_64_GOTPCRELX:
1882  case ELF::R_X86_64_REX_GOTPCRELX:
1883  case ELF::R_X86_64_PC32:
1884  case ELF::R_X86_64_PC64:
1885  case ELF::R_X86_64_64:
1886  // We know that these reloation types won't need a stub function. This list
1887  // can be extended as needed.
1888  return false;
1889  }
1890 }
1891 
1892 } // namespace llvm
RelocationEntry - used to represent relocations internally in the dynamic linker. ...
void push_back(const T &Elt)
Definition: SmallVector.h:212
static void or32AArch64Imm(void *L, uint64_t Imm)
LLVM_ATTRIBUTE_NORETURN void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:115
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:136
void writeInt16BE(uint8_t *Addr, uint16_t Value)
void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner)
Log all errors (if any) in E to OS.
Definition: Error.cpp:57
StringRef getFileName() const
Definition: Binary.cpp:41
uint64_t readBytesUnaligned(uint8_t *Src, unsigned Size) const
Endian-aware read Read the least significant Size bytes from Src.
uint64_t getLoadAddressWithOffset(unsigned OffsetBytes) const
Return the load address of this section with an offset.
RuntimeDyld::MemoryManager & MemMgr
format_object< Ts... > format(const char *Fmt, const Ts &... Vals)
These are helper functions used to produce formatted output.
Definition: Format.h:124
size_t getGOTEntrySize() override
iterator find(StringRef Key)
Definition: StringMap.h:337
constexpr bool isInt< 8 >(int64_t x)
Definition: MathExtras.h:295
This class is the base class for all object file types.
Definition: ObjectFile.h:189
RuntimeDyldCheckerImpl * Checker
static uint16_t applyPPChigher(uint64_t value)
void write32le(void *P, uint32_t V)
Definition: Endian.h:404
static uint16_t applyPPChighesta(uint64_t value)
uint8_t * getAddress() const
Error takeError()
Take ownership of the stored error.
Definition: Error.h:537
static uint16_t applyPPChighera(uint64_t value)
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE const char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:128
static std::unique_ptr< RuntimeDyldELF > create(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver)
static int64_t decodePPC64LocalEntryOffset(unsigned Other)
Definition: ELF.h:398
unsigned SectionID
SectionID - the section this relocation points to.
DataRefImpl getRawDataRefImpl() const
Definition: SymbolicFile.h:205
This is a value type class that represents a single relocation in the list of relocations in the obje...
Definition: ObjectFile.h:51
std::unique_ptr< RuntimeDyld::LoadedObjectInfo > loadObject(const object::ObjectFile &O) override
std::map< RelocationValueRef, uintptr_t > StubMap
Tagged union holding either a T or a Error.
Definition: CachePruning.h:23
section_iterator_range sections() const
Definition: ObjectFile.h:273
Expected< relocation_iterator > processRelocationRef(unsigned SectionID, relocation_iterator RelI, const ObjectFile &Obj, ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) override
Parses one or more object file relocations (some object files use relocation pairs) and stores it to ...
static uint16_t applyPPChi(uint64_t value)
std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type cast(const Y &Val)
Definition: Casting.h:240
Expected< section_iterator > getSection() const
Get section this symbol is defined in reference to.
Definition: ObjectFile.h:363
const Elf_Sym * getSymbol(DataRefImpl Sym) const
#define P(N)
void addRelocationForSymbol(const RelocationEntry &RE, StringRef SymbolName)
virtual uint8_t getBytesInAddress() const =0
The number of bytes used to represent an address in this object file format.
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
void registerEHFrames() override
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
Error errorCodeToError(std::error_code EC)
Helper for converting an std::error_code to a Error.
Definition: Error.cpp:78
static uint64_t getBits(uint64_t Val, int Start, int End)
void addRelocationForSection(const RelocationEntry &RE, unsigned SectionID)
static StringRef getArchTypePrefix(ArchType Kind)
getArchTypePrefix - Get the "prefix" canonical name for the Kind architecture.
Definition: Triple.cpp:79
Expected< int64_t > getAddend() const
Symbol resolution.
Definition: JITSymbol.h:260
static const unsigned End
static uint16_t applyPPClo(uint64_t value)
virtual basic_symbol_iterator symbol_end() const =0
static Expected< ELFObjectFile< ELFT > > create(MemoryBufferRef Object)
void writeInt32BE(uint8_t *Addr, uint32_t Value)
Expected< unsigned > findOrEmitSection(const ObjectFile &Obj, const SectionRef &Section, bool IsCode, ObjSectionToIDMap &LocalSections)
Find Section in LocalSections.
bool isCompatibleFile(const object::ObjectFile &Obj) const override
DenseMap< SID, SID > SectionToGOTMap
static void write(bool isBE, void *P, T V)
virtual uint8_t * allocateDataSection(uintptr_t Size, unsigned Alignment, unsigned SectionID, StringRef SectionName, bool IsReadOnly)=0
Allocate a memory block of (at least) the given size suitable for data.
bool isELF() const
Definition: Binary.h:109
DataRefImpl getRawDataRefImpl() const
Definition: ObjectFile.h:462
void consumeError(Error Err)
Consume a Error without doing anything.
Definition: Error.h:962
uint64_t getType() const
Definition: ObjectFile.h:492
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
bool isLittleEndian() const
Definition: Binary.h:131
static uint16_t applyPPChighest(uint64_t value)
void handleAllErrors(Error E, HandlerTs &&... Handlers)
Behaves the same as handleErrors, except that it requires that all errors be handled by the given han...
Definition: Error.h:889
static ErrorSuccess success()
Create a success value.
Definition: Error.h:313
constexpr bool isInt< 32 >(int64_t x)
Definition: MathExtras.h:301
Represents base address of the CU.
Definition: DWARFUnit.h:163
Error finalizeLoad(const ObjectFile &Obj, ObjSectionToIDMap &SectionMap) override
virtual section_iterator section_begin() const =0
Expected< SymbolRef::Type > getType() const
Definition: ObjectFile.h:367
int64_t Addend
Addend - the relocation addend encoded in the instruction itself.
std::error_code getName(StringRef &Result) const
Definition: ObjectFile.h:398
uint32_t RelType
RelType - relocation type.
JITSymbolResolver & Resolver
virtual std::error_code getPlatformFlags(unsigned &Result) const
Returns platform-specific object flags, if any.
Definition: ObjectFile.h:290
LLVM_NODISCARD bool isa(const Y &Val)
Definition: Casting.h:142
static void or32le(void *P, int32_t V)
uint8_t * createStubFunction(uint8_t *Addr, unsigned AbiVariant=0)
Emits long jump instruction to Addr.
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
StringMap - This is an unconventional map that is specialized for handling keys that are "strings"...
Definition: StringMap.h:224
Target - Wrapper for Target specific information.
static std::unique_ptr< MemoryBuffer > getMemBufferCopy(StringRef InputData, const Twine &BufferName="")
Open the specified memory range as a MemoryBuffer, copying the contents and taking ownership of it...
uintptr_t getStubOffset() const
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool equals(StringRef RHS) const
equals - Check for string equality, this is more efficient than compare() when the relative ordering ...
Definition: StringRef.h:169
This is a value type class that represents a single symbol in the list of symbols in the object file...
Definition: ObjectFile.h:128
Triple::ArchType Arch
uint64_t Offset
Offset - offset into the section.
virtual section_iterator section_end() const =0
std::map< SectionRef, unsigned > ObjSectionToIDMap
uint8_t * getAddressWithOffset(unsigned OffsetBytes) const
Return the address of this section with an offset.
#define I(x, y, z)
Definition: MD5.cpp:58
void writeInt64BE(uint8_t *Addr, uint64_t Value)
uint32_t read32le(const void *P)
Definition: Endian.h:369
StringRef getName() const
SymInfo contains information about symbol: it&#39;s address and section index which is -1LL for absolute ...
SectionEntry - represents a section emitted into memory by the dynamic linker.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver)
A raw_ostream that writes to an std::string.
Definition: raw_ostream.h:462
LLVM Value Representation.
Definition: Value.h:73
RTDyldSymbolTable GlobalSymbolTable
Lightweight error class with error context and mandatory checking.
Definition: Error.h:156
std::underlying_type< E >::type Mask()
Get a bitmask with 1s in all places up to the high-order bit of E&#39;s largest value.
Definition: BitmaskEnum.h:81
static void write32AArch64Addr(void *L, uint64_t Imm)
const char SectionName[]
Definition: AMDGPUPTNote.h:24
#define DEBUG(X)
Definition: Debug.h:118
void advanceStubOffset(unsigned StubSize)
#define LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
Definition: ELFTypes.h:133
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
virtual void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr, size_t Size)=0
Register the EH frames with the runtime so that c++ exceptions work.
Expected< ObjSectionToIDMap > loadObjectImpl(const object::ObjectFile &Obj)
static uint16_t applyPPCha(uint64_t value)
virtual StringRef getFileFormatName() const =0
StringRef getData() const
Definition: Binary.cpp:39
typename ELFT::Shdr Elf_Shdr
Definition: ELF.h:57
iterator end()
Definition: StringMap.h:322
This is a value type class that represents a single section in the list of sections in the object fil...
Definition: ObjectFile.h:80