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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/STLExtras.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/Triple.h"
20 #include "llvm/BinaryFormat/ELF.h"
22 #include "llvm/Object/ObjectFile.h"
23 #include "llvm/Support/Endian.h"
25 
26 using namespace llvm;
27 using namespace llvm::object;
28 using namespace llvm::support::endian;
29 
30 #define DEBUG_TYPE "dyld"
31 
32 static void or32le(void *P, int32_t V) { write32le(P, read32le(P) | V); }
33 
34 static void or32AArch64Imm(void *L, uint64_t Imm) {
35  or32le(L, (Imm & 0xFFF) << 10);
36 }
37 
38 template <class T> static void write(bool isBE, void *P, T V) {
39  isBE ? write<T, support::big>(P, V) : write<T, support::little>(P, V);
40 }
41 
42 static void write32AArch64Addr(void *L, uint64_t Imm) {
43  uint32_t ImmLo = (Imm & 0x3) << 29;
44  uint32_t ImmHi = (Imm & 0x1FFFFC) << 3;
45  uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3);
46  write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi);
47 }
48 
49 // Return the bits [Start, End] from Val shifted Start bits.
50 // For instance, getBits(0xF0, 4, 8) returns 0xF.
51 static uint64_t getBits(uint64_t Val, int Start, int End) {
52  uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1;
53  return (Val >> Start) & Mask;
54 }
55 
56 namespace {
57 
58 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> {
60 
61  typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
62  typedef Elf_Sym_Impl<ELFT> Elf_Sym;
63  typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
64  typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
65 
66  typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
67 
68  typedef typename ELFT::uint addr_type;
69 
70  DyldELFObject(ELFObjectFile<ELFT> &&Obj);
71 
72 public:
74  create(MemoryBufferRef Wrapper);
75 
76  void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
77 
78  void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr);
79 
80  // Methods for type inquiry through isa, cast and dyn_cast
81  static bool classof(const Binary *v) {
82  return (isa<ELFObjectFile<ELFT>>(v) &&
83  classof(cast<ELFObjectFile<ELFT>>(v)));
84  }
85  static bool classof(const ELFObjectFile<ELFT> *v) {
86  return v->isDyldType();
87  }
88 };
89 
90 
91 
92 // The MemoryBuffer passed into this constructor is just a wrapper around the
93 // actual memory. Ultimately, the Binary parent class will take ownership of
94 // this MemoryBuffer object but not the underlying memory.
95 template <class ELFT>
96 DyldELFObject<ELFT>::DyldELFObject(ELFObjectFile<ELFT> &&Obj)
97  : ELFObjectFile<ELFT>(std::move(Obj)) {
98  this->isDyldELFObject = true;
99 }
100 
101 template <class ELFT>
103 DyldELFObject<ELFT>::create(MemoryBufferRef Wrapper) {
104  auto Obj = ELFObjectFile<ELFT>::create(Wrapper);
105  if (auto E = Obj.takeError())
106  return std::move(E);
107  std::unique_ptr<DyldELFObject<ELFT>> Ret(
108  new DyldELFObject<ELFT>(std::move(*Obj)));
109  return std::move(Ret);
110 }
111 
112 template <class ELFT>
113 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
114  uint64_t Addr) {
115  DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
116  Elf_Shdr *shdr =
117  const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
118 
119  // This assumes the address passed in matches the target address bitness
120  // The template-based type cast handles everything else.
121  shdr->sh_addr = static_cast<addr_type>(Addr);
122 }
123 
124 template <class ELFT>
125 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
126  uint64_t Addr) {
127 
128  Elf_Sym *sym = const_cast<Elf_Sym *>(
130 
131  // This assumes the address passed in matches the target address bitness
132  // The template-based type cast handles everything else.
133  sym->st_value = static_cast<addr_type>(Addr);
134 }
135 
136 class LoadedELFObjectInfo final
137  : public LoadedObjectInfoHelper<LoadedELFObjectInfo,
138  RuntimeDyld::LoadedObjectInfo> {
139 public:
140  LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
141  : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
142 
144  getObjectForDebug(const ObjectFile &Obj) const override;
145 };
146 
147 template <typename ELFT>
149 createRTDyldELFObject(MemoryBufferRef Buffer, const ObjectFile &SourceObject,
150  const LoadedELFObjectInfo &L) {
151  typedef typename ELFT::Shdr Elf_Shdr;
152  typedef typename ELFT::uint addr_type;
153 
155  DyldELFObject<ELFT>::create(Buffer);
156  if (Error E = ObjOrErr.takeError())
157  return std::move(E);
158 
159  std::unique_ptr<DyldELFObject<ELFT>> Obj = std::move(*ObjOrErr);
160 
161  // Iterate over all sections in the object.
162  auto SI = SourceObject.section_begin();
163  for (const auto &Sec : Obj->sections()) {
165  Sec.getName(SectionName);
166  if (SectionName != "") {
167  DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
168  Elf_Shdr *shdr = const_cast<Elf_Shdr *>(
169  reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
170 
171  if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) {
172  // This assumes that the address passed in matches the target address
173  // bitness. The template-based type cast handles everything else.
174  shdr->sh_addr = static_cast<addr_type>(SecLoadAddr);
175  }
176  }
177  ++SI;
178  }
179 
180  return std::move(Obj);
181 }
182 
184 createELFDebugObject(const ObjectFile &Obj, const LoadedELFObjectInfo &L) {
185  assert(Obj.isELF() && "Not an ELF object file.");
186 
187  std::unique_ptr<MemoryBuffer> Buffer =
189 
190  Expected<std::unique_ptr<ObjectFile>> DebugObj(nullptr);
191  handleAllErrors(DebugObj.takeError());
192  if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian())
193  DebugObj =
194  createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L);
195  else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian())
196  DebugObj =
197  createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L);
198  else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian())
199  DebugObj =
200  createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L);
201  else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian())
202  DebugObj =
203  createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L);
204  else
205  llvm_unreachable("Unexpected ELF format");
206 
207  handleAllErrors(DebugObj.takeError());
208  return OwningBinary<ObjectFile>(std::move(*DebugObj), std::move(Buffer));
209 }
210 
212 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const {
213  return createELFDebugObject(Obj, *this);
214 }
215 
216 } // anonymous namespace
217 
218 namespace llvm {
219 
222  : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {}
224 
226  for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
227  SID EHFrameSID = UnregisteredEHFrameSections[i];
228  uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
229  uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
230  size_t EHFrameSize = Sections[EHFrameSID].getSize();
231  MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
232  }
233  UnregisteredEHFrameSections.clear();
234 }
235 
236 std::unique_ptr<RuntimeDyldELF>
240  switch (Arch) {
241  default:
242  return make_unique<RuntimeDyldELF>(MemMgr, Resolver);
243  case Triple::mips:
244  case Triple::mipsel:
245  case Triple::mips64:
246  case Triple::mips64el:
247  return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver);
248  }
249 }
250 
251 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
253  if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
254  return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr);
255  else {
256  HasError = true;
257  raw_string_ostream ErrStream(ErrorStr);
258  logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, "");
259  return nullptr;
260  }
261 }
262 
263 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
264  uint64_t Offset, uint64_t Value,
265  uint32_t Type, int64_t Addend,
266  uint64_t SymOffset) {
267  switch (Type) {
268  default:
269  llvm_unreachable("Relocation type not implemented yet!");
270  break;
271  case ELF::R_X86_64_NONE:
272  break;
273  case ELF::R_X86_64_64: {
275  Value + Addend;
276  LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
277  << format("%p\n", Section.getAddressWithOffset(Offset)));
278  break;
279  }
280  case ELF::R_X86_64_32:
281  case ELF::R_X86_64_32S: {
282  Value += Addend;
283  assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) ||
284  (Type == ELF::R_X86_64_32S &&
285  ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN)));
286  uint32_t TruncatedAddr = (Value & 0xFFFFFFFF);
288  TruncatedAddr;
289  LLVM_DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at "
290  << format("%p\n", Section.getAddressWithOffset(Offset)));
291  break;
292  }
293  case ELF::R_X86_64_PC8: {
294  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
295  int64_t RealOffset = Value + Addend - FinalAddress;
296  assert(isInt<8>(RealOffset));
297  int8_t TruncOffset = (RealOffset & 0xFF);
298  Section.getAddress()[Offset] = TruncOffset;
299  break;
300  }
301  case ELF::R_X86_64_PC32: {
302  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
303  int64_t RealOffset = Value + Addend - FinalAddress;
304  assert(isInt<32>(RealOffset));
305  int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
307  TruncOffset;
308  break;
309  }
310  case ELF::R_X86_64_PC64: {
311  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
312  int64_t RealOffset = Value + Addend - FinalAddress;
314  RealOffset;
315  break;
316  }
317  }
318 }
319 
320 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
321  uint64_t Offset, uint32_t Value,
322  uint32_t Type, int32_t Addend) {
323  switch (Type) {
324  case ELF::R_386_32: {
326  Value + Addend;
327  break;
328  }
329  // Handle R_386_PLT32 like R_386_PC32 since it should be able to
330  // reach any 32 bit address.
331  case ELF::R_386_PLT32:
332  case ELF::R_386_PC32: {
333  uint32_t FinalAddress =
334  Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
335  uint32_t RealOffset = Value + Addend - FinalAddress;
337  RealOffset;
338  break;
339  }
340  default:
341  // There are other relocation types, but it appears these are the
342  // only ones currently used by the LLVM ELF object writer
343  llvm_unreachable("Relocation type not implemented yet!");
344  break;
345  }
346 }
347 
348 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
349  uint64_t Offset, uint64_t Value,
350  uint32_t Type, int64_t Addend) {
351  uint32_t *TargetPtr =
352  reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
353  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
354  // Data should use target endian. Code should always use little endian.
355  bool isBE = Arch == Triple::aarch64_be;
356 
357  LLVM_DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
358  << format("%llx", Section.getAddressWithOffset(Offset))
359  << " FinalAddress: 0x" << format("%llx", FinalAddress)
360  << " Value: 0x" << format("%llx", Value) << " Type: 0x"
361  << format("%x", Type) << " Addend: 0x"
362  << format("%llx", Addend) << "\n");
363 
364  switch (Type) {
365  default:
366  llvm_unreachable("Relocation type not implemented yet!");
367  break;
368  case ELF::R_AARCH64_ABS16: {
369  uint64_t Result = Value + Addend;
370  assert(static_cast<int64_t>(Result) >= INT16_MIN && Result < UINT16_MAX);
371  write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU));
372  break;
373  }
374  case ELF::R_AARCH64_ABS32: {
375  uint64_t Result = Value + Addend;
376  assert(static_cast<int64_t>(Result) >= INT32_MIN && Result < UINT32_MAX);
377  write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU));
378  break;
379  }
380  case ELF::R_AARCH64_ABS64:
381  write(isBE, TargetPtr, Value + Addend);
382  break;
383  case ELF::R_AARCH64_PREL32: {
384  uint64_t Result = Value + Addend - FinalAddress;
385  assert(static_cast<int64_t>(Result) >= INT32_MIN &&
386  static_cast<int64_t>(Result) <= UINT32_MAX);
387  write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU));
388  break;
389  }
390  case ELF::R_AARCH64_PREL64:
391  write(isBE, TargetPtr, Value + Addend - FinalAddress);
392  break;
393  case ELF::R_AARCH64_CALL26: // fallthrough
394  case ELF::R_AARCH64_JUMP26: {
395  // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
396  // calculation.
397  uint64_t BranchImm = Value + Addend - FinalAddress;
398 
399  // "Check that -2^27 <= result < 2^27".
400  assert(isInt<28>(BranchImm));
401  or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2);
402  break;
403  }
404  case ELF::R_AARCH64_MOVW_UABS_G3:
405  or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43);
406  break;
407  case ELF::R_AARCH64_MOVW_UABS_G2_NC:
408  or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27);
409  break;
410  case ELF::R_AARCH64_MOVW_UABS_G1_NC:
411  or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11);
412  break;
413  case ELF::R_AARCH64_MOVW_UABS_G0_NC:
414  or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5);
415  break;
416  case ELF::R_AARCH64_ADR_PREL_PG_HI21: {
417  // Operation: Page(S+A) - Page(P)
418  uint64_t Result =
419  ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL);
420 
421  // Check that -2^32 <= X < 2^32
422  assert(isInt<33>(Result) && "overflow check failed for relocation");
423 
424  // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken
425  // from bits 32:12 of X.
426  write32AArch64Addr(TargetPtr, Result >> 12);
427  break;
428  }
429  case ELF::R_AARCH64_ADD_ABS_LO12_NC:
430  // Operation: S + A
431  // Immediate goes in bits 21:10 of LD/ST instruction, taken
432  // from bits 11:0 of X
433  or32AArch64Imm(TargetPtr, Value + Addend);
434  break;
435  case ELF::R_AARCH64_LDST8_ABS_LO12_NC:
436  // Operation: S + A
437  // Immediate goes in bits 21:10 of LD/ST instruction, taken
438  // from bits 11:0 of X
439  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11));
440  break;
441  case ELF::R_AARCH64_LDST16_ABS_LO12_NC:
442  // Operation: S + A
443  // Immediate goes in bits 21:10 of LD/ST instruction, taken
444  // from bits 11:1 of X
445  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11));
446  break;
447  case ELF::R_AARCH64_LDST32_ABS_LO12_NC:
448  // Operation: S + A
449  // Immediate goes in bits 21:10 of LD/ST instruction, taken
450  // from bits 11:2 of X
451  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11));
452  break;
453  case ELF::R_AARCH64_LDST64_ABS_LO12_NC:
454  // Operation: S + A
455  // Immediate goes in bits 21:10 of LD/ST instruction, taken
456  // from bits 11:3 of X
457  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11));
458  break;
459  case ELF::R_AARCH64_LDST128_ABS_LO12_NC:
460  // Operation: S + A
461  // Immediate goes in bits 21:10 of LD/ST instruction, taken
462  // from bits 11:4 of X
463  or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11));
464  break;
465  }
466 }
467 
468 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
469  uint64_t Offset, uint32_t Value,
470  uint32_t Type, int32_t Addend) {
471  // TODO: Add Thumb relocations.
472  uint32_t *TargetPtr =
473  reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
474  uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
475  Value += Addend;
476 
477  LLVM_DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
478  << Section.getAddressWithOffset(Offset)
479  << " FinalAddress: " << format("%p", FinalAddress)
480  << " Value: " << format("%x", Value)
481  << " Type: " << format("%x", Type)
482  << " Addend: " << format("%x", Addend) << "\n");
483 
484  switch (Type) {
485  default:
486  llvm_unreachable("Not implemented relocation type!");
487 
488  case ELF::R_ARM_NONE:
489  break;
490  // Write a 31bit signed offset
491  case ELF::R_ARM_PREL31:
492  support::ulittle32_t::ref{TargetPtr} =
493  (support::ulittle32_t::ref{TargetPtr} & 0x80000000) |
494  ((Value - FinalAddress) & ~0x80000000);
495  break;
496  case ELF::R_ARM_TARGET1:
497  case ELF::R_ARM_ABS32:
498  support::ulittle32_t::ref{TargetPtr} = Value;
499  break;
500  // Write first 16 bit of 32 bit value to the mov instruction.
501  // Last 4 bit should be shifted.
502  case ELF::R_ARM_MOVW_ABS_NC:
503  case ELF::R_ARM_MOVT_ABS:
504  if (Type == ELF::R_ARM_MOVW_ABS_NC)
505  Value = Value & 0xFFFF;
506  else if (Type == ELF::R_ARM_MOVT_ABS)
507  Value = (Value >> 16) & 0xFFFF;
508  support::ulittle32_t::ref{TargetPtr} =
509  (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) |
510  (((Value >> 12) & 0xF) << 16);
511  break;
512  // Write 24 bit relative value to the branch instruction.
513  case ELF::R_ARM_PC24: // Fall through.
514  case ELF::R_ARM_CALL: // Fall through.
515  case ELF::R_ARM_JUMP24:
516  int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
517  RelValue = (RelValue & 0x03FFFFFC) >> 2;
518  assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE);
519  support::ulittle32_t::ref{TargetPtr} =
520  (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue;
521  break;
522  }
523 }
524 
525 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) {
526  if (Arch == Triple::UnknownArch ||
527  !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) {
528  IsMipsO32ABI = false;
529  IsMipsN32ABI = false;
530  IsMipsN64ABI = false;
531  return;
532  }
533  if (auto *E = dyn_cast<ELFObjectFileBase>(&Obj)) {
534  unsigned AbiVariant = E->getPlatformFlags();
535  IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32;
536  IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2;
537  }
538  IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips");
539 }
540 
541 // Return the .TOC. section and offset.
542 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj,
543  ObjSectionToIDMap &LocalSections,
544  RelocationValueRef &Rel) {
545  // Set a default SectionID in case we do not find a TOC section below.
546  // This may happen for references to TOC base base (sym@toc, .odp
547  // relocation) without a .toc directive. In this case just use the
548  // first section (which is usually the .odp) since the code won't
549  // reference the .toc base directly.
550  Rel.SymbolName = nullptr;
551  Rel.SectionID = 0;
552 
553  // The TOC consists of sections .got, .toc, .tocbss, .plt in that
554  // order. The TOC starts where the first of these sections starts.
555  for (auto &Section: Obj.sections()) {
557  if (auto EC = Section.getName(SectionName))
558  return errorCodeToError(EC);
559 
560  if (SectionName == ".got"
561  || SectionName == ".toc"
562  || SectionName == ".tocbss"
563  || SectionName == ".plt") {
564  if (auto SectionIDOrErr =
565  findOrEmitSection(Obj, Section, false, LocalSections))
566  Rel.SectionID = *SectionIDOrErr;
567  else
568  return SectionIDOrErr.takeError();
569  break;
570  }
571  }
572 
573  // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
574  // thus permitting a full 64 Kbytes segment.
575  Rel.Addend = 0x8000;
576 
577  return Error::success();
578 }
579 
580 // Returns the sections and offset associated with the ODP entry referenced
581 // by Symbol.
582 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj,
583  ObjSectionToIDMap &LocalSections,
584  RelocationValueRef &Rel) {
585  // Get the ELF symbol value (st_value) to compare with Relocation offset in
586  // .opd entries
587  for (section_iterator si = Obj.section_begin(), se = Obj.section_end();
588  si != se; ++si) {
589  section_iterator RelSecI = si->getRelocatedSection();
590  if (RelSecI == Obj.section_end())
591  continue;
592 
593  StringRef RelSectionName;
594  if (auto EC = RelSecI->getName(RelSectionName))
595  return errorCodeToError(EC);
596 
597  if (RelSectionName != ".opd")
598  continue;
599 
600  for (elf_relocation_iterator i = si->relocation_begin(),
601  e = si->relocation_end();
602  i != e;) {
603  // The R_PPC64_ADDR64 relocation indicates the first field
604  // of a .opd entry
605  uint64_t TypeFunc = i->getType();
606  if (TypeFunc != ELF::R_PPC64_ADDR64) {
607  ++i;
608  continue;
609  }
610 
611  uint64_t TargetSymbolOffset = i->getOffset();
612  symbol_iterator TargetSymbol = i->getSymbol();
613  int64_t Addend;
614  if (auto AddendOrErr = i->getAddend())
615  Addend = *AddendOrErr;
616  else
617  return AddendOrErr.takeError();
618 
619  ++i;
620  if (i == e)
621  break;
622 
623  // Just check if following relocation is a R_PPC64_TOC
624  uint64_t TypeTOC = i->getType();
625  if (TypeTOC != ELF::R_PPC64_TOC)
626  continue;
627 
628  // Finally compares the Symbol value and the target symbol offset
629  // to check if this .opd entry refers to the symbol the relocation
630  // points to.
631  if (Rel.Addend != (int64_t)TargetSymbolOffset)
632  continue;
633 
634  section_iterator TSI = Obj.section_end();
635  if (auto TSIOrErr = TargetSymbol->getSection())
636  TSI = *TSIOrErr;
637  else
638  return TSIOrErr.takeError();
639  assert(TSI != Obj.section_end() && "TSI should refer to a valid section");
640 
641  bool IsCode = TSI->isText();
642  if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode,
643  LocalSections))
644  Rel.SectionID = *SectionIDOrErr;
645  else
646  return SectionIDOrErr.takeError();
647  Rel.Addend = (intptr_t)Addend;
648  return Error::success();
649  }
650  }
651  llvm_unreachable("Attempting to get address of ODP entry!");
652 }
653 
654 // Relocation masks following the #lo(value), #hi(value), #ha(value),
655 // #higher(value), #highera(value), #highest(value), and #highesta(value)
656 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi
657 // document.
658 
659 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; }
660 
661 static inline uint16_t applyPPChi(uint64_t value) {
662  return (value >> 16) & 0xffff;
663 }
664 
665 static inline uint16_t applyPPCha (uint64_t value) {
666  return ((value + 0x8000) >> 16) & 0xffff;
667 }
668 
669 static inline uint16_t applyPPChigher(uint64_t value) {
670  return (value >> 32) & 0xffff;
671 }
672 
673 static inline uint16_t applyPPChighera (uint64_t value) {
674  return ((value + 0x8000) >> 32) & 0xffff;
675 }
676 
677 static inline uint16_t applyPPChighest(uint64_t value) {
678  return (value >> 48) & 0xffff;
679 }
680 
681 static inline uint16_t applyPPChighesta (uint64_t value) {
682  return ((value + 0x8000) >> 48) & 0xffff;
683 }
684 
685 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section,
686  uint64_t Offset, uint64_t Value,
687  uint32_t Type, int64_t Addend) {
688  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
689  switch (Type) {
690  default:
691  llvm_unreachable("Relocation type not implemented yet!");
692  break;
693  case ELF::R_PPC_ADDR16_LO:
694  writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
695  break;
696  case ELF::R_PPC_ADDR16_HI:
697  writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
698  break;
699  case ELF::R_PPC_ADDR16_HA:
700  writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
701  break;
702  }
703 }
704 
705 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
706  uint64_t Offset, uint64_t Value,
707  uint32_t Type, int64_t Addend) {
708  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
709  switch (Type) {
710  default:
711  llvm_unreachable("Relocation type not implemented yet!");
712  break;
713  case ELF::R_PPC64_ADDR16:
714  writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
715  break;
716  case ELF::R_PPC64_ADDR16_DS:
717  writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
718  break;
719  case ELF::R_PPC64_ADDR16_LO:
720  writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
721  break;
722  case ELF::R_PPC64_ADDR16_LO_DS:
723  writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
724  break;
725  case ELF::R_PPC64_ADDR16_HI:
726  case ELF::R_PPC64_ADDR16_HIGH:
727  writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
728  break;
729  case ELF::R_PPC64_ADDR16_HA:
730  case ELF::R_PPC64_ADDR16_HIGHA:
731  writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
732  break;
733  case ELF::R_PPC64_ADDR16_HIGHER:
734  writeInt16BE(LocalAddress, applyPPChigher(Value + Addend));
735  break;
736  case ELF::R_PPC64_ADDR16_HIGHERA:
737  writeInt16BE(LocalAddress, applyPPChighera(Value + Addend));
738  break;
739  case ELF::R_PPC64_ADDR16_HIGHEST:
740  writeInt16BE(LocalAddress, applyPPChighest(Value + Addend));
741  break;
742  case ELF::R_PPC64_ADDR16_HIGHESTA:
743  writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend));
744  break;
745  case ELF::R_PPC64_ADDR14: {
746  assert(((Value + Addend) & 3) == 0);
747  // Preserve the AA/LK bits in the branch instruction
748  uint8_t aalk = *(LocalAddress + 3);
749  writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
750  } break;
751  case ELF::R_PPC64_REL16_LO: {
752  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
753  uint64_t Delta = Value - FinalAddress + Addend;
754  writeInt16BE(LocalAddress, applyPPClo(Delta));
755  } break;
756  case ELF::R_PPC64_REL16_HI: {
757  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
758  uint64_t Delta = Value - FinalAddress + Addend;
759  writeInt16BE(LocalAddress, applyPPChi(Delta));
760  } break;
761  case ELF::R_PPC64_REL16_HA: {
762  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
763  uint64_t Delta = Value - FinalAddress + Addend;
764  writeInt16BE(LocalAddress, applyPPCha(Delta));
765  } break;
766  case ELF::R_PPC64_ADDR32: {
767  int64_t Result = static_cast<int64_t>(Value + Addend);
768  if (SignExtend64<32>(Result) != Result)
769  llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
770  writeInt32BE(LocalAddress, Result);
771  } break;
772  case ELF::R_PPC64_REL24: {
773  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
774  int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend);
775  if (SignExtend64<26>(delta) != delta)
776  llvm_unreachable("Relocation R_PPC64_REL24 overflow");
777  // We preserve bits other than LI field, i.e. PO and AA/LK fields.
778  uint32_t Inst = readBytesUnaligned(LocalAddress, 4);
779  writeInt32BE(LocalAddress, (Inst & 0xFC000003) | (delta & 0x03FFFFFC));
780  } break;
781  case ELF::R_PPC64_REL32: {
782  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
783  int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend);
784  if (SignExtend64<32>(delta) != delta)
785  llvm_unreachable("Relocation R_PPC64_REL32 overflow");
786  writeInt32BE(LocalAddress, delta);
787  } break;
788  case ELF::R_PPC64_REL64: {
789  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
790  uint64_t Delta = Value - FinalAddress + Addend;
791  writeInt64BE(LocalAddress, Delta);
792  } break;
793  case ELF::R_PPC64_ADDR64:
794  writeInt64BE(LocalAddress, Value + Addend);
795  break;
796  }
797 }
798 
799 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
800  uint64_t Offset, uint64_t Value,
801  uint32_t Type, int64_t Addend) {
802  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
803  switch (Type) {
804  default:
805  llvm_unreachable("Relocation type not implemented yet!");
806  break;
807  case ELF::R_390_PC16DBL:
808  case ELF::R_390_PLT16DBL: {
809  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
810  assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
811  writeInt16BE(LocalAddress, Delta / 2);
812  break;
813  }
814  case ELF::R_390_PC32DBL:
815  case ELF::R_390_PLT32DBL: {
816  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
817  assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
818  writeInt32BE(LocalAddress, Delta / 2);
819  break;
820  }
821  case ELF::R_390_PC16: {
822  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
823  assert(int16_t(Delta) == Delta && "R_390_PC16 overflow");
824  writeInt16BE(LocalAddress, Delta);
825  break;
826  }
827  case ELF::R_390_PC32: {
828  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
829  assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
830  writeInt32BE(LocalAddress, Delta);
831  break;
832  }
833  case ELF::R_390_PC64: {
834  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
835  writeInt64BE(LocalAddress, Delta);
836  break;
837  }
838  case ELF::R_390_8:
839  *LocalAddress = (uint8_t)(Value + Addend);
840  break;
841  case ELF::R_390_16:
842  writeInt16BE(LocalAddress, Value + Addend);
843  break;
844  case ELF::R_390_32:
845  writeInt32BE(LocalAddress, Value + Addend);
846  break;
847  case ELF::R_390_64:
848  writeInt64BE(LocalAddress, Value + Addend);
849  break;
850  }
851 }
852 
853 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section,
854  uint64_t Offset, uint64_t Value,
855  uint32_t Type, int64_t Addend) {
856  bool isBE = Arch == Triple::bpfeb;
857 
858  switch (Type) {
859  default:
860  llvm_unreachable("Relocation type not implemented yet!");
861  break;
862  case ELF::R_BPF_NONE:
863  break;
864  case ELF::R_BPF_64_64: {
865  write(isBE, Section.getAddressWithOffset(Offset), Value + Addend);
866  LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
867  << format("%p\n", Section.getAddressWithOffset(Offset)));
868  break;
869  }
870  case ELF::R_BPF_64_32: {
871  Value += Addend;
872  assert(Value <= UINT32_MAX);
873  write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value));
874  LLVM_DEBUG(dbgs() << "Writing " << format("%p", Value) << " at "
875  << format("%p\n", Section.getAddressWithOffset(Offset)));
876  break;
877  }
878  }
879 }
880 
881 // The target location for the relocation is described by RE.SectionID and
882 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
883 // SectionEntry has three members describing its location.
884 // SectionEntry::Address is the address at which the section has been loaded
885 // into memory in the current (host) process. SectionEntry::LoadAddress is the
886 // address that the section will have in the target process.
887 // SectionEntry::ObjAddress is the address of the bits for this section in the
888 // original emitted object image (also in the current address space).
889 //
890 // Relocations will be applied as if the section were loaded at
891 // SectionEntry::LoadAddress, but they will be applied at an address based
892 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to
893 // Target memory contents if they are required for value calculations.
894 //
895 // The Value parameter here is the load address of the symbol for the
896 // relocation to be applied. For relocations which refer to symbols in the
897 // current object Value will be the LoadAddress of the section in which
898 // the symbol resides (RE.Addend provides additional information about the
899 // symbol location). For external symbols, Value will be the address of the
900 // symbol in the target address space.
901 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
902  uint64_t Value) {
903  const SectionEntry &Section = Sections[RE.SectionID];
904  return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
905  RE.SymOffset, RE.SectionID);
906 }
907 
908 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
909  uint64_t Offset, uint64_t Value,
910  uint32_t Type, int64_t Addend,
911  uint64_t SymOffset, SID SectionID) {
912  switch (Arch) {
913  case Triple::x86_64:
914  resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset);
915  break;
916  case Triple::x86:
917  resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
918  (uint32_t)(Addend & 0xffffffffL));
919  break;
920  case Triple::aarch64:
921  case Triple::aarch64_be:
922  resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
923  break;
924  case Triple::arm: // Fall through.
925  case Triple::armeb:
926  case Triple::thumb:
927  case Triple::thumbeb:
928  resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
929  (uint32_t)(Addend & 0xffffffffL));
930  break;
931  case Triple::ppc:
932  resolvePPC32Relocation(Section, Offset, Value, Type, Addend);
933  break;
934  case Triple::ppc64: // Fall through.
935  case Triple::ppc64le:
936  resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
937  break;
938  case Triple::systemz:
939  resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
940  break;
941  case Triple::bpfel:
942  case Triple::bpfeb:
943  resolveBPFRelocation(Section, Offset, Value, Type, Addend);
944  break;
945  default:
946  llvm_unreachable("Unsupported CPU type!");
947  }
948 }
949 
950 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const {
951  return (void *)(Sections[SectionID].getObjAddress() + Offset);
952 }
953 
954 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) {
955  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
956  if (Value.SymbolName)
958  else
960 }
961 
962 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType,
963  bool IsLocal) const {
964  switch (RelType) {
965  case ELF::R_MICROMIPS_GOT16:
966  if (IsLocal)
967  return ELF::R_MICROMIPS_LO16;
968  break;
969  case ELF::R_MICROMIPS_HI16:
970  return ELF::R_MICROMIPS_LO16;
971  case ELF::R_MIPS_GOT16:
972  if (IsLocal)
973  return ELF::R_MIPS_LO16;
974  break;
975  case ELF::R_MIPS_HI16:
976  return ELF::R_MIPS_LO16;
977  case ELF::R_MIPS_PCHI16:
978  return ELF::R_MIPS_PCLO16;
979  default:
980  break;
981  }
982  return ELF::R_MIPS_NONE;
983 }
984 
985 // Sometimes we don't need to create thunk for a branch.
986 // This typically happens when branch target is located
987 // in the same object file. In such case target is either
988 // a weak symbol or symbol in a different executable section.
989 // This function checks if branch target is located in the
990 // same object file and if distance between source and target
991 // fits R_AARCH64_CALL26 relocation. If both conditions are
992 // met, it emits direct jump to the target and returns true.
993 // Otherwise false is returned and thunk is created.
994 bool RuntimeDyldELF::resolveAArch64ShortBranch(
995  unsigned SectionID, relocation_iterator RelI,
996  const RelocationValueRef &Value) {
997  uint64_t Address;
998  if (Value.SymbolName) {
999  auto Loc = GlobalSymbolTable.find(Value.SymbolName);
1000 
1001  // Don't create direct branch for external symbols.
1002  if (Loc == GlobalSymbolTable.end())
1003  return false;
1004 
1005  const auto &SymInfo = Loc->second;
1006  Address =
1007  uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset(
1008  SymInfo.getOffset()));
1009  } else {
1010  Address = uint64_t(Sections[Value.SectionID].getLoadAddress());
1011  }
1012  uint64_t Offset = RelI->getOffset();
1013  uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset);
1014 
1015  // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27
1016  // If distance between source and target is out of range then we should
1017  // create thunk.
1018  if (!isInt<28>(Address + Value.Addend - SourceAddress))
1019  return false;
1020 
1021  resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(),
1022  Value.Addend);
1023 
1024  return true;
1025 }
1026 
1027 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID,
1028  const RelocationValueRef &Value,
1029  relocation_iterator RelI,
1030  StubMap &Stubs) {
1031 
1032  LLVM_DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
1033  SectionEntry &Section = Sections[SectionID];
1034 
1035  uint64_t Offset = RelI->getOffset();
1036  unsigned RelType = RelI->getType();
1037  // Look for an existing stub.
1038  StubMap::const_iterator i = Stubs.find(Value);
1039  if (i != Stubs.end()) {
1040  resolveRelocation(Section, Offset,
1041  (uint64_t)Section.getAddressWithOffset(i->second),
1042  RelType, 0);
1043  LLVM_DEBUG(dbgs() << " Stub function found\n");
1044  } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) {
1045  // Create a new stub function.
1046  LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1047  Stubs[Value] = Section.getStubOffset();
1048  uint8_t *StubTargetAddr = createStubFunction(
1049  Section.getAddressWithOffset(Section.getStubOffset()));
1050 
1051  RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(),
1052  ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
1053  RelocationEntry REmovk_g2(SectionID,
1054  StubTargetAddr - Section.getAddress() + 4,
1055  ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
1056  RelocationEntry REmovk_g1(SectionID,
1057  StubTargetAddr - Section.getAddress() + 8,
1058  ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
1059  RelocationEntry REmovk_g0(SectionID,
1060  StubTargetAddr - Section.getAddress() + 12,
1061  ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
1062 
1063  if (Value.SymbolName) {
1064  addRelocationForSymbol(REmovz_g3, Value.SymbolName);
1065  addRelocationForSymbol(REmovk_g2, Value.SymbolName);
1066  addRelocationForSymbol(REmovk_g1, Value.SymbolName);
1067  addRelocationForSymbol(REmovk_g0, Value.SymbolName);
1068  } else {
1069  addRelocationForSection(REmovz_g3, Value.SectionID);
1070  addRelocationForSection(REmovk_g2, Value.SectionID);
1071  addRelocationForSection(REmovk_g1, Value.SectionID);
1072  addRelocationForSection(REmovk_g0, Value.SectionID);
1073  }
1074  resolveRelocation(Section, Offset,
1075  reinterpret_cast<uint64_t>(Section.getAddressWithOffset(
1076  Section.getStubOffset())),
1077  RelType, 0);
1078  Section.advanceStubOffset(getMaxStubSize());
1079  }
1080 }
1081 
1084  unsigned SectionID, relocation_iterator RelI, const ObjectFile &O,
1085  ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) {
1086  const auto &Obj = cast<ELFObjectFileBase>(O);
1087  uint64_t RelType = RelI->getType();
1088  int64_t Addend = 0;
1089  if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend())
1090  Addend = *AddendOrErr;
1091  else
1092  consumeError(AddendOrErr.takeError());
1093  elf_symbol_iterator Symbol = RelI->getSymbol();
1094 
1095  // Obtain the symbol name which is referenced in the relocation
1096  StringRef TargetName;
1097  if (Symbol != Obj.symbol_end()) {
1098  if (auto TargetNameOrErr = Symbol->getName())
1099  TargetName = *TargetNameOrErr;
1100  else
1101  return TargetNameOrErr.takeError();
1102  }
1103  LLVM_DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend
1104  << " TargetName: " << TargetName << "\n");
1105  RelocationValueRef Value;
1106  // First search for the symbol in the local symbol table
1107  SymbolRef::Type SymType = SymbolRef::ST_Unknown;
1108 
1109  // Search for the symbol in the global symbol table
1111  if (Symbol != Obj.symbol_end()) {
1112  gsi = GlobalSymbolTable.find(TargetName.data());
1113  Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType();
1114  if (!SymTypeOrErr) {
1115  std::string Buf;
1116  raw_string_ostream OS(Buf);
1117  logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, "");
1118  OS.flush();
1119  report_fatal_error(Buf);
1120  }
1121  SymType = *SymTypeOrErr;
1122  }
1123  if (gsi != GlobalSymbolTable.end()) {
1124  const auto &SymInfo = gsi->second;
1125  Value.SectionID = SymInfo.getSectionID();
1126  Value.Offset = SymInfo.getOffset();
1127  Value.Addend = SymInfo.getOffset() + Addend;
1128  } else {
1129  switch (SymType) {
1130  case SymbolRef::ST_Debug: {
1131  // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
1132  // and can be changed by another developers. Maybe best way is add
1133  // a new symbol type ST_Section to SymbolRef and use it.
1134  auto SectionOrErr = Symbol->getSection();
1135  if (!SectionOrErr) {
1136  std::string Buf;
1137  raw_string_ostream OS(Buf);
1138  logAllUnhandledErrors(SectionOrErr.takeError(), OS, "");
1139  OS.flush();
1140  report_fatal_error(Buf);
1141  }
1142  section_iterator si = *SectionOrErr;
1143  if (si == Obj.section_end())
1144  llvm_unreachable("Symbol section not found, bad object file format!");
1145  LLVM_DEBUG(dbgs() << "\t\tThis is section symbol\n");
1146  bool isCode = si->isText();
1147  if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode,
1148  ObjSectionToID))
1149  Value.SectionID = *SectionIDOrErr;
1150  else
1151  return SectionIDOrErr.takeError();
1152  Value.Addend = Addend;
1153  break;
1154  }
1155  case SymbolRef::ST_Data:
1156  case SymbolRef::ST_Function:
1157  case SymbolRef::ST_Unknown: {
1158  Value.SymbolName = TargetName.data();
1159  Value.Addend = Addend;
1160 
1161  // Absolute relocations will have a zero symbol ID (STN_UNDEF), which
1162  // will manifest here as a NULL symbol name.
1163  // We can set this as a valid (but empty) symbol name, and rely
1164  // on addRelocationForSymbol to handle this.
1165  if (!Value.SymbolName)
1166  Value.SymbolName = "";
1167  break;
1168  }
1169  default:
1170  llvm_unreachable("Unresolved symbol type!");
1171  break;
1172  }
1173  }
1174 
1175  uint64_t Offset = RelI->getOffset();
1176 
1177  LLVM_DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset
1178  << "\n");
1179  if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) {
1180  if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) {
1181  resolveAArch64Branch(SectionID, Value, RelI, Stubs);
1182  } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) {
1183  // Craete new GOT entry or find existing one. If GOT entry is
1184  // to be created, then we also emit ABS64 relocation for it.
1185  uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64);
1186  resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1187  ELF::R_AARCH64_ADR_PREL_PG_HI21);
1188 
1189  } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) {
1190  uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64);
1191  resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1192  ELF::R_AARCH64_LDST64_ABS_LO12_NC);
1193  } else {
1194  processSimpleRelocation(SectionID, Offset, RelType, Value);
1195  }
1196  } else if (Arch == Triple::arm) {
1197  if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL ||
1198  RelType == ELF::R_ARM_JUMP24) {
1199  // This is an ARM branch relocation, need to use a stub function.
1200  LLVM_DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n");
1201  SectionEntry &Section = Sections[SectionID];
1202 
1203  // Look for an existing stub.
1204  StubMap::const_iterator i = Stubs.find(Value);
1205  if (i != Stubs.end()) {
1206  resolveRelocation(
1207  Section, Offset,
1208  reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)),
1209  RelType, 0);
1210  LLVM_DEBUG(dbgs() << " Stub function found\n");
1211  } else {
1212  // Create a new stub function.
1213  LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1214  Stubs[Value] = Section.getStubOffset();
1215  uint8_t *StubTargetAddr = createStubFunction(
1216  Section.getAddressWithOffset(Section.getStubOffset()));
1217  RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1218  ELF::R_ARM_ABS32, Value.Addend);
1219  if (Value.SymbolName)
1221  else
1223 
1224  resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1225  Section.getAddressWithOffset(
1226  Section.getStubOffset())),
1227  RelType, 0);
1228  Section.advanceStubOffset(getMaxStubSize());
1229  }
1230  } else {
1231  uint32_t *Placeholder =
1232  reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset));
1233  if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 ||
1234  RelType == ELF::R_ARM_ABS32) {
1235  Value.Addend += *Placeholder;
1236  } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) {
1237  // See ELF for ARM documentation
1238  Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12));
1239  }
1240  processSimpleRelocation(SectionID, Offset, RelType, Value);
1241  }
1242  } else if (IsMipsO32ABI) {
1243  uint8_t *Placeholder = reinterpret_cast<uint8_t *>(
1244  computePlaceholderAddress(SectionID, Offset));
1245  uint32_t Opcode = readBytesUnaligned(Placeholder, 4);
1246  if (RelType == ELF::R_MIPS_26) {
1247  // This is an Mips branch relocation, need to use a stub function.
1248  LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1249  SectionEntry &Section = Sections[SectionID];
1250 
1251  // Extract the addend from the instruction.
1252  // We shift up by two since the Value will be down shifted again
1253  // when applying the relocation.
1254  uint32_t Addend = (Opcode & 0x03ffffff) << 2;
1255 
1256  Value.Addend += Addend;
1257 
1258  // Look up for existing stub.
1259  StubMap::const_iterator i = Stubs.find(Value);
1260  if (i != Stubs.end()) {
1261  RelocationEntry RE(SectionID, Offset, RelType, i->second);
1262  addRelocationForSection(RE, SectionID);
1263  LLVM_DEBUG(dbgs() << " Stub function found\n");
1264  } else {
1265  // Create a new stub function.
1266  LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1267  Stubs[Value] = Section.getStubOffset();
1268 
1269  unsigned AbiVariant = Obj.getPlatformFlags();
1270 
1271  uint8_t *StubTargetAddr = createStubFunction(
1272  Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
1273 
1274  // Creating Hi and Lo relocations for the filled stub instructions.
1275  RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
1276  ELF::R_MIPS_HI16, Value.Addend);
1277  RelocationEntry RELo(SectionID,
1278  StubTargetAddr - Section.getAddress() + 4,
1279  ELF::R_MIPS_LO16, Value.Addend);
1280 
1281  if (Value.SymbolName) {
1282  addRelocationForSymbol(REHi, Value.SymbolName);
1283  addRelocationForSymbol(RELo, Value.SymbolName);
1284  } else {
1285  addRelocationForSection(REHi, Value.SectionID);
1286  addRelocationForSection(RELo, Value.SectionID);
1287  }
1288 
1289  RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
1290  addRelocationForSection(RE, SectionID);
1291  Section.advanceStubOffset(getMaxStubSize());
1292  }
1293  } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) {
1294  int64_t Addend = (Opcode & 0x0000ffff) << 16;
1295  RelocationEntry RE(SectionID, Offset, RelType, Addend);
1296  PendingRelocs.push_back(std::make_pair(Value, RE));
1297  } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) {
1298  int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff);
1299  for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) {
1300  const RelocationValueRef &MatchingValue = I->first;
1301  RelocationEntry &Reloc = I->second;
1302  if (MatchingValue == Value &&
1303  RelType == getMatchingLoRelocation(Reloc.RelType) &&
1304  SectionID == Reloc.SectionID) {
1305  Reloc.Addend += Addend;
1306  if (Value.SymbolName)
1307  addRelocationForSymbol(Reloc, Value.SymbolName);
1308  else
1309  addRelocationForSection(Reloc, Value.SectionID);
1310  I = PendingRelocs.erase(I);
1311  } else
1312  ++I;
1313  }
1314  RelocationEntry RE(SectionID, Offset, RelType, Addend);
1315  if (Value.SymbolName)
1317  else
1319  } else {
1320  if (RelType == ELF::R_MIPS_32)
1321  Value.Addend += Opcode;
1322  else if (RelType == ELF::R_MIPS_PC16)
1323  Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2);
1324  else if (RelType == ELF::R_MIPS_PC19_S2)
1325  Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2);
1326  else if (RelType == ELF::R_MIPS_PC21_S2)
1327  Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2);
1328  else if (RelType == ELF::R_MIPS_PC26_S2)
1329  Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2);
1330  processSimpleRelocation(SectionID, Offset, RelType, Value);
1331  }
1332  } else if (IsMipsN32ABI || IsMipsN64ABI) {
1333  uint32_t r_type = RelType & 0xff;
1334  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1335  if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE
1336  || r_type == ELF::R_MIPS_GOT_DISP) {
1337  StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName);
1338  if (i != GOTSymbolOffsets.end())
1339  RE.SymOffset = i->second;
1340  else {
1341  RE.SymOffset = allocateGOTEntries(1);
1342  GOTSymbolOffsets[TargetName] = RE.SymOffset;
1343  }
1344  if (Value.SymbolName)
1346  else
1348  } else if (RelType == ELF::R_MIPS_26) {
1349  // This is an Mips branch relocation, need to use a stub function.
1350  LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1351  SectionEntry &Section = Sections[SectionID];
1352 
1353  // Look up for existing stub.
1354  StubMap::const_iterator i = Stubs.find(Value);
1355  if (i != Stubs.end()) {
1356  RelocationEntry RE(SectionID, Offset, RelType, i->second);
1357  addRelocationForSection(RE, SectionID);
1358  LLVM_DEBUG(dbgs() << " Stub function found\n");
1359  } else {
1360  // Create a new stub function.
1361  LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1362  Stubs[Value] = Section.getStubOffset();
1363 
1364  unsigned AbiVariant = Obj.getPlatformFlags();
1365 
1366  uint8_t *StubTargetAddr = createStubFunction(
1367  Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
1368 
1369  if (IsMipsN32ABI) {
1370  // Creating Hi and Lo relocations for the filled stub instructions.
1371  RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
1372  ELF::R_MIPS_HI16, Value.Addend);
1373  RelocationEntry RELo(SectionID,
1374  StubTargetAddr - Section.getAddress() + 4,
1375  ELF::R_MIPS_LO16, Value.Addend);
1376  if (Value.SymbolName) {
1377  addRelocationForSymbol(REHi, Value.SymbolName);
1378  addRelocationForSymbol(RELo, Value.SymbolName);
1379  } else {
1380  addRelocationForSection(REHi, Value.SectionID);
1381  addRelocationForSection(RELo, Value.SectionID);
1382  }
1383  } else {
1384  // Creating Highest, Higher, Hi and Lo relocations for the filled stub
1385  // instructions.
1386  RelocationEntry REHighest(SectionID,
1387  StubTargetAddr - Section.getAddress(),
1388  ELF::R_MIPS_HIGHEST, Value.Addend);
1389  RelocationEntry REHigher(SectionID,
1390  StubTargetAddr - Section.getAddress() + 4,
1391  ELF::R_MIPS_HIGHER, Value.Addend);
1392  RelocationEntry REHi(SectionID,
1393  StubTargetAddr - Section.getAddress() + 12,
1394  ELF::R_MIPS_HI16, Value.Addend);
1395  RelocationEntry RELo(SectionID,
1396  StubTargetAddr - Section.getAddress() + 20,
1397  ELF::R_MIPS_LO16, Value.Addend);
1398  if (Value.SymbolName) {
1399  addRelocationForSymbol(REHighest, Value.SymbolName);
1400  addRelocationForSymbol(REHigher, Value.SymbolName);
1401  addRelocationForSymbol(REHi, Value.SymbolName);
1402  addRelocationForSymbol(RELo, Value.SymbolName);
1403  } else {
1404  addRelocationForSection(REHighest, Value.SectionID);
1405  addRelocationForSection(REHigher, Value.SectionID);
1406  addRelocationForSection(REHi, Value.SectionID);
1407  addRelocationForSection(RELo, Value.SectionID);
1408  }
1409  }
1410  RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
1411  addRelocationForSection(RE, SectionID);
1412  Section.advanceStubOffset(getMaxStubSize());
1413  }
1414  } else {
1415  processSimpleRelocation(SectionID, Offset, RelType, Value);
1416  }
1417 
1418  } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1419  if (RelType == ELF::R_PPC64_REL24) {
1420  // Determine ABI variant in use for this object.
1421  unsigned AbiVariant = Obj.getPlatformFlags();
1422  AbiVariant &= ELF::EF_PPC64_ABI;
1423  // A PPC branch relocation will need a stub function if the target is
1424  // an external symbol (either Value.SymbolName is set, or SymType is
1425  // Symbol::ST_Unknown) or if the target address is not within the
1426  // signed 24-bits branch address.
1427  SectionEntry &Section = Sections[SectionID];
1428  uint8_t *Target = Section.getAddressWithOffset(Offset);
1429  bool RangeOverflow = false;
1430  bool IsExtern = Value.SymbolName || SymType == SymbolRef::ST_Unknown;
1431  if (!IsExtern) {
1432  if (AbiVariant != 2) {
1433  // In the ELFv1 ABI, a function call may point to the .opd entry,
1434  // so the final symbol value is calculated based on the relocation
1435  // values in the .opd section.
1436  if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value))
1437  return std::move(Err);
1438  } else {
1439  // In the ELFv2 ABI, a function symbol may provide a local entry
1440  // point, which must be used for direct calls.
1441  if (Value.SectionID == SectionID){
1442  uint8_t SymOther = Symbol->getOther();
1443  Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther);
1444  }
1445  }
1446  uint8_t *RelocTarget =
1447  Sections[Value.SectionID].getAddressWithOffset(Value.Addend);
1448  int64_t delta = static_cast<int64_t>(Target - RelocTarget);
1449  // If it is within 26-bits branch range, just set the branch target
1450  if (SignExtend64<26>(delta) != delta) {
1451  RangeOverflow = true;
1452  } else if ((AbiVariant != 2) ||
1453  (AbiVariant == 2 && Value.SectionID == SectionID)) {
1454  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1456  }
1457  }
1458  if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID) ||
1459  RangeOverflow) {
1460  // It is an external symbol (either Value.SymbolName is set, or
1461  // SymType is SymbolRef::ST_Unknown) or out of range.
1462  StubMap::const_iterator i = Stubs.find(Value);
1463  if (i != Stubs.end()) {
1464  // Symbol function stub already created, just relocate to it
1465  resolveRelocation(Section, Offset,
1466  reinterpret_cast<uint64_t>(
1467  Section.getAddressWithOffset(i->second)),
1468  RelType, 0);
1469  LLVM_DEBUG(dbgs() << " Stub function found\n");
1470  } else {
1471  // Create a new stub function.
1472  LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1473  Stubs[Value] = Section.getStubOffset();
1474  uint8_t *StubTargetAddr = createStubFunction(
1475  Section.getAddressWithOffset(Section.getStubOffset()),
1476  AbiVariant);
1477  RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1478  ELF::R_PPC64_ADDR64, Value.Addend);
1479 
1480  // Generates the 64-bits address loads as exemplified in section
1481  // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to
1482  // apply to the low part of the instructions, so we have to update
1483  // the offset according to the target endianness.
1484  uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress();
1485  if (!IsTargetLittleEndian)
1486  StubRelocOffset += 2;
1487 
1488  RelocationEntry REhst(SectionID, StubRelocOffset + 0,
1489  ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
1490  RelocationEntry REhr(SectionID, StubRelocOffset + 4,
1491  ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
1492  RelocationEntry REh(SectionID, StubRelocOffset + 12,
1493  ELF::R_PPC64_ADDR16_HI, Value.Addend);
1494  RelocationEntry REl(SectionID, StubRelocOffset + 16,
1495  ELF::R_PPC64_ADDR16_LO, Value.Addend);
1496 
1497  if (Value.SymbolName) {
1498  addRelocationForSymbol(REhst, Value.SymbolName);
1499  addRelocationForSymbol(REhr, Value.SymbolName);
1500  addRelocationForSymbol(REh, Value.SymbolName);
1501  addRelocationForSymbol(REl, Value.SymbolName);
1502  } else {
1503  addRelocationForSection(REhst, Value.SectionID);
1504  addRelocationForSection(REhr, Value.SectionID);
1505  addRelocationForSection(REh, Value.SectionID);
1506  addRelocationForSection(REl, Value.SectionID);
1507  }
1508 
1509  resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1510  Section.getAddressWithOffset(
1511  Section.getStubOffset())),
1512  RelType, 0);
1513  Section.advanceStubOffset(getMaxStubSize());
1514  }
1515  if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID)) {
1516  // Restore the TOC for external calls
1517  if (AbiVariant == 2)
1518  writeInt32BE(Target + 4, 0xE8410018); // ld r2,24(r1)
1519  else
1520  writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1)
1521  }
1522  }
1523  } else if (RelType == ELF::R_PPC64_TOC16 ||
1524  RelType == ELF::R_PPC64_TOC16_DS ||
1525  RelType == ELF::R_PPC64_TOC16_LO ||
1526  RelType == ELF::R_PPC64_TOC16_LO_DS ||
1527  RelType == ELF::R_PPC64_TOC16_HI ||
1528  RelType == ELF::R_PPC64_TOC16_HA) {
1529  // These relocations are supposed to subtract the TOC address from
1530  // the final value. This does not fit cleanly into the RuntimeDyld
1531  // scheme, since there may be *two* sections involved in determining
1532  // the relocation value (the section of the symbol referred to by the
1533  // relocation, and the TOC section associated with the current module).
1534  //
1535  // Fortunately, these relocations are currently only ever generated
1536  // referring to symbols that themselves reside in the TOC, which means
1537  // that the two sections are actually the same. Thus they cancel out
1538  // and we can immediately resolve the relocation right now.
1539  switch (RelType) {
1540  case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break;
1541  case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break;
1542  case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break;
1543  case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break;
1544  case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break;
1545  case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break;
1546  default: llvm_unreachable("Wrong relocation type.");
1547  }
1548 
1549  RelocationValueRef TOCValue;
1550  if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue))
1551  return std::move(Err);
1552  if (Value.SymbolName || Value.SectionID != TOCValue.SectionID)
1553  llvm_unreachable("Unsupported TOC relocation.");
1554  Value.Addend -= TOCValue.Addend;
1555  resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0);
1556  } else {
1557  // There are two ways to refer to the TOC address directly: either
1558  // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are
1559  // ignored), or via any relocation that refers to the magic ".TOC."
1560  // symbols (in which case the addend is respected).
1561  if (RelType == ELF::R_PPC64_TOC) {
1562  RelType = ELF::R_PPC64_ADDR64;
1563  if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1564  return std::move(Err);
1565  } else if (TargetName == ".TOC.") {
1566  if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1567  return std::move(Err);
1568  Value.Addend += Addend;
1569  }
1570 
1571  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1572 
1573  if (Value.SymbolName)
1575  else
1577  }
1578  } else if (Arch == Triple::systemz &&
1579  (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) {
1580  // Create function stubs for both PLT and GOT references, regardless of
1581  // whether the GOT reference is to data or code. The stub contains the
1582  // full address of the symbol, as needed by GOT references, and the
1583  // executable part only adds an overhead of 8 bytes.
1584  //
1585  // We could try to conserve space by allocating the code and data
1586  // parts of the stub separately. However, as things stand, we allocate
1587  // a stub for every relocation, so using a GOT in JIT code should be
1588  // no less space efficient than using an explicit constant pool.
1589  LLVM_DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1590  SectionEntry &Section = Sections[SectionID];
1591 
1592  // Look for an existing stub.
1593  StubMap::const_iterator i = Stubs.find(Value);
1594  uintptr_t StubAddress;
1595  if (i != Stubs.end()) {
1596  StubAddress = uintptr_t(Section.getAddressWithOffset(i->second));
1597  LLVM_DEBUG(dbgs() << " Stub function found\n");
1598  } else {
1599  // Create a new stub function.
1600  LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1601 
1602  uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1603  uintptr_t StubAlignment = getStubAlignment();
1604  StubAddress =
1605  (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1606  -StubAlignment;
1607  unsigned StubOffset = StubAddress - BaseAddress;
1608 
1609  Stubs[Value] = StubOffset;
1610  createStubFunction((uint8_t *)StubAddress);
1611  RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64,
1612  Value.Offset);
1613  if (Value.SymbolName)
1615  else
1617  Section.advanceStubOffset(getMaxStubSize());
1618  }
1619 
1620  if (RelType == ELF::R_390_GOTENT)
1621  resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL,
1622  Addend);
1623  else
1624  resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1625  } else if (Arch == Triple::x86_64) {
1626  if (RelType == ELF::R_X86_64_PLT32) {
1627  // The way the PLT relocations normally work is that the linker allocates
1628  // the
1629  // PLT and this relocation makes a PC-relative call into the PLT. The PLT
1630  // entry will then jump to an address provided by the GOT. On first call,
1631  // the
1632  // GOT address will point back into PLT code that resolves the symbol. After
1633  // the first call, the GOT entry points to the actual function.
1634  //
1635  // For local functions we're ignoring all of that here and just replacing
1636  // the PLT32 relocation type with PC32, which will translate the relocation
1637  // into a PC-relative call directly to the function. For external symbols we
1638  // can't be sure the function will be within 2^32 bytes of the call site, so
1639  // we need to create a stub, which calls into the GOT. This case is
1640  // equivalent to the usual PLT implementation except that we use the stub
1641  // mechanism in RuntimeDyld (which puts stubs at the end of the section)
1642  // rather than allocating a PLT section.
1643  if (Value.SymbolName) {
1644  // This is a call to an external function.
1645  // Look for an existing stub.
1646  SectionEntry &Section = Sections[SectionID];
1647  StubMap::const_iterator i = Stubs.find(Value);
1648  uintptr_t StubAddress;
1649  if (i != Stubs.end()) {
1650  StubAddress = uintptr_t(Section.getAddress()) + i->second;
1651  LLVM_DEBUG(dbgs() << " Stub function found\n");
1652  } else {
1653  // Create a new stub function (equivalent to a PLT entry).
1654  LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1655 
1656  uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1657  uintptr_t StubAlignment = getStubAlignment();
1658  StubAddress =
1659  (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1660  -StubAlignment;
1661  unsigned StubOffset = StubAddress - BaseAddress;
1662  Stubs[Value] = StubOffset;
1663  createStubFunction((uint8_t *)StubAddress);
1664 
1665  // Bump our stub offset counter
1666  Section.advanceStubOffset(getMaxStubSize());
1667 
1668  // Allocate a GOT Entry
1669  uint64_t GOTOffset = allocateGOTEntries(1);
1670 
1671  // The load of the GOT address has an addend of -4
1672  resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4,
1673  ELF::R_X86_64_PC32);
1674 
1675  // Fill in the value of the symbol we're targeting into the GOT
1677  computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64),
1678  Value.SymbolName);
1679  }
1680 
1681  // Make the target call a call into the stub table.
1682  resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32,
1683  Addend);
1684  } else {
1685  RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend,
1686  Value.Offset);
1688  }
1689  } else if (RelType == ELF::R_X86_64_GOTPCREL ||
1690  RelType == ELF::R_X86_64_GOTPCRELX ||
1691  RelType == ELF::R_X86_64_REX_GOTPCRELX) {
1692  uint64_t GOTOffset = allocateGOTEntries(1);
1693  resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1694  ELF::R_X86_64_PC32);
1695 
1696  // Fill in the value of the symbol we're targeting into the GOT
1697  RelocationEntry RE =
1698  computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64);
1699  if (Value.SymbolName)
1701  else
1703  } else if (RelType == ELF::R_X86_64_PC32) {
1704  Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1705  processSimpleRelocation(SectionID, Offset, RelType, Value);
1706  } else if (RelType == ELF::R_X86_64_PC64) {
1707  Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset));
1708  processSimpleRelocation(SectionID, Offset, RelType, Value);
1709  } else {
1710  processSimpleRelocation(SectionID, Offset, RelType, Value);
1711  }
1712  } else {
1713  if (Arch == Triple::x86) {
1714  Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1715  }
1716  processSimpleRelocation(SectionID, Offset, RelType, Value);
1717  }
1718  return ++RelI;
1719 }
1720 
1722  // We don't use the GOT in all of these cases, but it's essentially free
1723  // to put them all here.
1724  size_t Result = 0;
1725  switch (Arch) {
1726  case Triple::x86_64:
1727  case Triple::aarch64:
1728  case Triple::aarch64_be:
1729  case Triple::ppc64:
1730  case Triple::ppc64le:
1731  case Triple::systemz:
1732  Result = sizeof(uint64_t);
1733  break;
1734  case Triple::x86:
1735  case Triple::arm:
1736  case Triple::thumb:
1737  Result = sizeof(uint32_t);
1738  break;
1739  case Triple::mips:
1740  case Triple::mipsel:
1741  case Triple::mips64:
1742  case Triple::mips64el:
1743  if (IsMipsO32ABI || IsMipsN32ABI)
1744  Result = sizeof(uint32_t);
1745  else if (IsMipsN64ABI)
1746  Result = sizeof(uint64_t);
1747  else
1748  llvm_unreachable("Mips ABI not handled");
1749  break;
1750  default:
1751  llvm_unreachable("Unsupported CPU type!");
1752  }
1753  return Result;
1754 }
1755 
1756 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) {
1757  if (GOTSectionID == 0) {
1758  GOTSectionID = Sections.size();
1759  // Reserve a section id. We'll allocate the section later
1760  // once we know the total size
1761  Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0));
1762  }
1763  uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize();
1764  CurrentGOTIndex += no;
1765  return StartOffset;
1766 }
1767 
1768 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value,
1769  unsigned GOTRelType) {
1770  auto E = GOTOffsetMap.insert({Value, 0});
1771  if (E.second) {
1772  uint64_t GOTOffset = allocateGOTEntries(1);
1773 
1774  // Create relocation for newly created GOT entry
1775  RelocationEntry RE =
1776  computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType);
1777  if (Value.SymbolName)
1779  else
1781 
1782  E.first->second = GOTOffset;
1783  }
1784 
1785  return E.first->second;
1786 }
1787 
1788 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID,
1789  uint64_t Offset,
1790  uint64_t GOTOffset,
1791  uint32_t Type) {
1792  // Fill in the relative address of the GOT Entry into the stub
1793  RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset);
1794  addRelocationForSection(GOTRE, GOTSectionID);
1795 }
1796 
1797 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset,
1798  uint64_t SymbolOffset,
1799  uint32_t Type) {
1800  return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset);
1801 }
1802 
1804  ObjSectionToIDMap &SectionMap) {
1805  if (IsMipsO32ABI)
1806  if (!PendingRelocs.empty())
1807  return make_error<RuntimeDyldError>("Can't find matching LO16 reloc");
1808 
1809  // If necessary, allocate the global offset table
1810  if (GOTSectionID != 0) {
1811  // Allocate memory for the section
1812  size_t TotalSize = CurrentGOTIndex * getGOTEntrySize();
1813  uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(),
1814  GOTSectionID, ".got", false);
1815  if (!Addr)
1816  return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!");
1817 
1818  Sections[GOTSectionID] =
1819  SectionEntry(".got", Addr, TotalSize, TotalSize, 0);
1820 
1821  if (Checker)
1822  Checker->registerSection(Obj.getFileName(), GOTSectionID);
1823 
1824  // For now, initialize all GOT entries to zero. We'll fill them in as
1825  // needed when GOT-based relocations are applied.
1826  memset(Addr, 0, TotalSize);
1827  if (IsMipsN32ABI || IsMipsN64ABI) {
1828  // To correctly resolve Mips GOT relocations, we need a mapping from
1829  // object's sections to GOTs.
1830  for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
1831  SI != SE; ++SI) {
1832  if (SI->relocation_begin() != SI->relocation_end()) {
1833  section_iterator RelocatedSection = SI->getRelocatedSection();
1834  ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection);
1835  assert (i != SectionMap.end());
1836  SectionToGOTMap[i->second] = GOTSectionID;
1837  }
1838  }
1839  GOTSymbolOffsets.clear();
1840  }
1841  }
1842 
1843  // Look for and record the EH frame section.
1844  ObjSectionToIDMap::iterator i, e;
1845  for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
1846  const SectionRef &Section = i->first;
1847  StringRef Name;
1848  Section.getName(Name);
1849  if (Name == ".eh_frame") {
1850  UnregisteredEHFrameSections.push_back(i->second);
1851  break;
1852  }
1853  }
1854 
1855  GOTSectionID = 0;
1856  CurrentGOTIndex = 0;
1857 
1858  return Error::success();
1859 }
1860 
1862  return Obj.isELF();
1863 }
1864 
1865 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const {
1866  unsigned RelTy = R.getType();
1868  return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE ||
1869  RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC;
1870 
1871  if (Arch == Triple::x86_64)
1872  return RelTy == ELF::R_X86_64_GOTPCREL ||
1873  RelTy == ELF::R_X86_64_GOTPCRELX ||
1874  RelTy == ELF::R_X86_64_REX_GOTPCRELX;
1875  return false;
1876 }
1877 
1878 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const {
1879  if (Arch != Triple::x86_64)
1880  return true; // Conservative answer
1881 
1882  switch (R.getType()) {
1883  default:
1884  return true; // Conservative answer
1885 
1886 
1887  case ELF::R_X86_64_GOTPCREL:
1888  case ELF::R_X86_64_GOTPCRELX:
1889  case ELF::R_X86_64_REX_GOTPCRELX:
1890  case ELF::R_X86_64_PC32:
1891  case ELF::R_X86_64_PC64:
1892  case ELF::R_X86_64_64:
1893  // We know that these reloation types won't need a stub function. This list
1894  // can be extended as needed.
1895  return false;
1896  }
1897 }
1898 
1899 } // namespace llvm
RelocationEntry - used to represent relocations internally in the dynamic linker. ...
void push_back(const T &Elt)
Definition: SmallVector.h:213
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:137
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:333
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:190
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:52
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:278
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:362
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)
Interface for looking up the initializer for a variable name, used by Init::resolveReferences.
Definition: Record.h:1790
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 interface.
Definition: JITSymbol.h:292
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:461
void consumeError(Error Err)
Consume a Error without doing anything.
Definition: Error.h:962
uint64_t getType() const
Definition: ObjectFile.h:491
#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 by contract all errors must 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:226
Error finalizeLoad(const ObjectFile &Obj, ObjSectionToIDMap &SectionMap) override
virtual section_iterator section_begin() const =0
Expected< SymbolRef::Type > getType() const
Definition: ObjectFile.h:366
int64_t Addend
Addend - the relocation addend encoded in the instruction itself.
std::error_code getName(StringRef &Result) const
Definition: ObjectFile.h:397
uint32_t RelType
RelType - relocation type.
JITSymbolResolver & Resolver
virtual unsigned getPlatformFlags() const =0
Returns platform-specific object flags, if any.
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:133
StringMap - This is an unconventional map that is specialized for handling keys that are "strings"...
Definition: StringMap.h:220
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:129
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:477
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
void advanceStubOffset(unsigned StubSize)
#define LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
Definition: ELFTypes.h:102
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)
#define LLVM_DEBUG(X)
Definition: Debug.h:119
virtual StringRef getFileFormatName() const =0
StringRef getData() const
Definition: Binary.cpp:39
iterator end()
Definition: StringMap.h:318
This is a value type class that represents a single section in the list of sections in the object fil...
Definition: ObjectFile.h:81