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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 
221  JITSymbolResolver &Resolver)
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  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  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  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" << format("%llx", Addend)
362  << "\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  DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
478  << Section.getAddressWithOffset(Offset)
479  << " FinalAddress: " << format("%p", FinalAddress) << " Value: "
480  << format("%x", Value) << " Type: " << format("%x", Type)
481  << " Addend: " << format("%x", Addend) << "\n");
482 
483  switch (Type) {
484  default:
485  llvm_unreachable("Not implemented relocation type!");
486 
487  case ELF::R_ARM_NONE:
488  break;
489  // Write a 31bit signed offset
490  case ELF::R_ARM_PREL31:
491  support::ulittle32_t::ref{TargetPtr} =
492  (support::ulittle32_t::ref{TargetPtr} & 0x80000000) |
493  ((Value - FinalAddress) & ~0x80000000);
494  break;
495  case ELF::R_ARM_TARGET1:
496  case ELF::R_ARM_ABS32:
497  support::ulittle32_t::ref{TargetPtr} = Value;
498  break;
499  // Write first 16 bit of 32 bit value to the mov instruction.
500  // Last 4 bit should be shifted.
501  case ELF::R_ARM_MOVW_ABS_NC:
502  case ELF::R_ARM_MOVT_ABS:
503  if (Type == ELF::R_ARM_MOVW_ABS_NC)
504  Value = Value & 0xFFFF;
505  else if (Type == ELF::R_ARM_MOVT_ABS)
506  Value = (Value >> 16) & 0xFFFF;
507  support::ulittle32_t::ref{TargetPtr} =
508  (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) |
509  (((Value >> 12) & 0xF) << 16);
510  break;
511  // Write 24 bit relative value to the branch instruction.
512  case ELF::R_ARM_PC24: // Fall through.
513  case ELF::R_ARM_CALL: // Fall through.
514  case ELF::R_ARM_JUMP24:
515  int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
516  RelValue = (RelValue & 0x03FFFFFC) >> 2;
517  assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE);
518  support::ulittle32_t::ref{TargetPtr} =
519  (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue;
520  break;
521  }
522 }
523 
524 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) {
525  if (Arch == Triple::UnknownArch ||
526  !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) {
527  IsMipsO32ABI = false;
528  IsMipsN32ABI = false;
529  IsMipsN64ABI = false;
530  return;
531  }
532  if (auto *E = dyn_cast<ELFObjectFileBase>(&Obj)) {
533  unsigned AbiVariant = E->getPlatformFlags();
534  IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32;
535  IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2;
536  }
537  IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips");
538 }
539 
540 // Return the .TOC. section and offset.
541 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj,
542  ObjSectionToIDMap &LocalSections,
543  RelocationValueRef &Rel) {
544  // Set a default SectionID in case we do not find a TOC section below.
545  // This may happen for references to TOC base base (sym@toc, .odp
546  // relocation) without a .toc directive. In this case just use the
547  // first section (which is usually the .odp) since the code won't
548  // reference the .toc base directly.
549  Rel.SymbolName = nullptr;
550  Rel.SectionID = 0;
551 
552  // The TOC consists of sections .got, .toc, .tocbss, .plt in that
553  // order. The TOC starts where the first of these sections starts.
554  for (auto &Section: Obj.sections()) {
556  if (auto EC = Section.getName(SectionName))
557  return errorCodeToError(EC);
558 
559  if (SectionName == ".got"
560  || SectionName == ".toc"
561  || SectionName == ".tocbss"
562  || SectionName == ".plt") {
563  if (auto SectionIDOrErr =
564  findOrEmitSection(Obj, Section, false, LocalSections))
565  Rel.SectionID = *SectionIDOrErr;
566  else
567  return SectionIDOrErr.takeError();
568  break;
569  }
570  }
571 
572  // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
573  // thus permitting a full 64 Kbytes segment.
574  Rel.Addend = 0x8000;
575 
576  return Error::success();
577 }
578 
579 // Returns the sections and offset associated with the ODP entry referenced
580 // by Symbol.
581 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj,
582  ObjSectionToIDMap &LocalSections,
583  RelocationValueRef &Rel) {
584  // Get the ELF symbol value (st_value) to compare with Relocation offset in
585  // .opd entries
586  for (section_iterator si = Obj.section_begin(), se = Obj.section_end();
587  si != se; ++si) {
588  section_iterator RelSecI = si->getRelocatedSection();
589  if (RelSecI == Obj.section_end())
590  continue;
591 
592  StringRef RelSectionName;
593  if (auto EC = RelSecI->getName(RelSectionName))
594  return errorCodeToError(EC);
595 
596  if (RelSectionName != ".opd")
597  continue;
598 
599  for (elf_relocation_iterator i = si->relocation_begin(),
600  e = si->relocation_end();
601  i != e;) {
602  // The R_PPC64_ADDR64 relocation indicates the first field
603  // of a .opd entry
604  uint64_t TypeFunc = i->getType();
605  if (TypeFunc != ELF::R_PPC64_ADDR64) {
606  ++i;
607  continue;
608  }
609 
610  uint64_t TargetSymbolOffset = i->getOffset();
611  symbol_iterator TargetSymbol = i->getSymbol();
612  int64_t Addend;
613  if (auto AddendOrErr = i->getAddend())
614  Addend = *AddendOrErr;
615  else
616  return AddendOrErr.takeError();
617 
618  ++i;
619  if (i == e)
620  break;
621 
622  // Just check if following relocation is a R_PPC64_TOC
623  uint64_t TypeTOC = i->getType();
624  if (TypeTOC != ELF::R_PPC64_TOC)
625  continue;
626 
627  // Finally compares the Symbol value and the target symbol offset
628  // to check if this .opd entry refers to the symbol the relocation
629  // points to.
630  if (Rel.Addend != (int64_t)TargetSymbolOffset)
631  continue;
632 
633  section_iterator TSI = Obj.section_end();
634  if (auto TSIOrErr = TargetSymbol->getSection())
635  TSI = *TSIOrErr;
636  else
637  return TSIOrErr.takeError();
638  assert(TSI != Obj.section_end() && "TSI should refer to a valid section");
639 
640  bool IsCode = TSI->isText();
641  if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode,
642  LocalSections))
643  Rel.SectionID = *SectionIDOrErr;
644  else
645  return SectionIDOrErr.takeError();
646  Rel.Addend = (intptr_t)Addend;
647  return Error::success();
648  }
649  }
650  llvm_unreachable("Attempting to get address of ODP entry!");
651 }
652 
653 // Relocation masks following the #lo(value), #hi(value), #ha(value),
654 // #higher(value), #highera(value), #highest(value), and #highesta(value)
655 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi
656 // document.
657 
658 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; }
659 
660 static inline uint16_t applyPPChi(uint64_t value) {
661  return (value >> 16) & 0xffff;
662 }
663 
664 static inline uint16_t applyPPCha (uint64_t value) {
665  return ((value + 0x8000) >> 16) & 0xffff;
666 }
667 
668 static inline uint16_t applyPPChigher(uint64_t value) {
669  return (value >> 32) & 0xffff;
670 }
671 
672 static inline uint16_t applyPPChighera (uint64_t value) {
673  return ((value + 0x8000) >> 32) & 0xffff;
674 }
675 
676 static inline uint16_t applyPPChighest(uint64_t value) {
677  return (value >> 48) & 0xffff;
678 }
679 
680 static inline uint16_t applyPPChighesta (uint64_t value) {
681  return ((value + 0x8000) >> 48) & 0xffff;
682 }
683 
684 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section,
685  uint64_t Offset, uint64_t Value,
686  uint32_t Type, int64_t Addend) {
687  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
688  switch (Type) {
689  default:
690  llvm_unreachable("Relocation type not implemented yet!");
691  break;
692  case ELF::R_PPC_ADDR16_LO:
693  writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
694  break;
695  case ELF::R_PPC_ADDR16_HI:
696  writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
697  break;
698  case ELF::R_PPC_ADDR16_HA:
699  writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
700  break;
701  }
702 }
703 
704 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
705  uint64_t Offset, uint64_t Value,
706  uint32_t Type, int64_t Addend) {
707  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
708  switch (Type) {
709  default:
710  llvm_unreachable("Relocation type not implemented yet!");
711  break;
712  case ELF::R_PPC64_ADDR16:
713  writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
714  break;
715  case ELF::R_PPC64_ADDR16_DS:
716  writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
717  break;
718  case ELF::R_PPC64_ADDR16_LO:
719  writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
720  break;
721  case ELF::R_PPC64_ADDR16_LO_DS:
722  writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
723  break;
724  case ELF::R_PPC64_ADDR16_HI:
725  writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
726  break;
727  case ELF::R_PPC64_ADDR16_HA:
728  writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
729  break;
730  case ELF::R_PPC64_ADDR16_HIGHER:
731  writeInt16BE(LocalAddress, applyPPChigher(Value + Addend));
732  break;
733  case ELF::R_PPC64_ADDR16_HIGHERA:
734  writeInt16BE(LocalAddress, applyPPChighera(Value + Addend));
735  break;
736  case ELF::R_PPC64_ADDR16_HIGHEST:
737  writeInt16BE(LocalAddress, applyPPChighest(Value + Addend));
738  break;
739  case ELF::R_PPC64_ADDR16_HIGHESTA:
740  writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend));
741  break;
742  case ELF::R_PPC64_ADDR14: {
743  assert(((Value + Addend) & 3) == 0);
744  // Preserve the AA/LK bits in the branch instruction
745  uint8_t aalk = *(LocalAddress + 3);
746  writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
747  } break;
748  case ELF::R_PPC64_REL16_LO: {
749  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
750  uint64_t Delta = Value - FinalAddress + Addend;
751  writeInt16BE(LocalAddress, applyPPClo(Delta));
752  } break;
753  case ELF::R_PPC64_REL16_HI: {
754  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
755  uint64_t Delta = Value - FinalAddress + Addend;
756  writeInt16BE(LocalAddress, applyPPChi(Delta));
757  } break;
758  case ELF::R_PPC64_REL16_HA: {
759  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
760  uint64_t Delta = Value - FinalAddress + Addend;
761  writeInt16BE(LocalAddress, applyPPCha(Delta));
762  } break;
763  case ELF::R_PPC64_ADDR32: {
764  int64_t Result = static_cast<int64_t>(Value + Addend);
765  if (SignExtend64<32>(Result) != Result)
766  llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
767  writeInt32BE(LocalAddress, Result);
768  } break;
769  case ELF::R_PPC64_REL24: {
770  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
771  int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend);
772  if (SignExtend64<26>(delta) != delta)
773  llvm_unreachable("Relocation R_PPC64_REL24 overflow");
774  // Generates a 'bl <address>' instruction
775  writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
776  } break;
777  case ELF::R_PPC64_REL32: {
778  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
779  int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend);
780  if (SignExtend64<32>(delta) != delta)
781  llvm_unreachable("Relocation R_PPC64_REL32 overflow");
782  writeInt32BE(LocalAddress, delta);
783  } break;
784  case ELF::R_PPC64_REL64: {
785  uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
786  uint64_t Delta = Value - FinalAddress + Addend;
787  writeInt64BE(LocalAddress, Delta);
788  } break;
789  case ELF::R_PPC64_ADDR64:
790  writeInt64BE(LocalAddress, Value + Addend);
791  break;
792  }
793 }
794 
795 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
796  uint64_t Offset, uint64_t Value,
797  uint32_t Type, int64_t Addend) {
798  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
799  switch (Type) {
800  default:
801  llvm_unreachable("Relocation type not implemented yet!");
802  break;
803  case ELF::R_390_PC16DBL:
804  case ELF::R_390_PLT16DBL: {
805  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
806  assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
807  writeInt16BE(LocalAddress, Delta / 2);
808  break;
809  }
810  case ELF::R_390_PC32DBL:
811  case ELF::R_390_PLT32DBL: {
812  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
813  assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
814  writeInt32BE(LocalAddress, Delta / 2);
815  break;
816  }
817  case ELF::R_390_PC16: {
818  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
819  assert(int16_t(Delta) == Delta && "R_390_PC16 overflow");
820  writeInt16BE(LocalAddress, Delta);
821  break;
822  }
823  case ELF::R_390_PC32: {
824  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
825  assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
826  writeInt32BE(LocalAddress, Delta);
827  break;
828  }
829  case ELF::R_390_PC64: {
830  int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
831  writeInt64BE(LocalAddress, Delta);
832  break;
833  }
834  case ELF::R_390_8:
835  *LocalAddress = (uint8_t)(Value + Addend);
836  break;
837  case ELF::R_390_16:
838  writeInt16BE(LocalAddress, Value + Addend);
839  break;
840  case ELF::R_390_32:
841  writeInt32BE(LocalAddress, Value + Addend);
842  break;
843  case ELF::R_390_64:
844  writeInt64BE(LocalAddress, Value + Addend);
845  break;
846  }
847 }
848 
849 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section,
850  uint64_t Offset, uint64_t Value,
851  uint32_t Type, int64_t Addend) {
852  bool isBE = Arch == Triple::bpfeb;
853 
854  switch (Type) {
855  default:
856  llvm_unreachable("Relocation type not implemented yet!");
857  break;
858  case ELF::R_BPF_NONE:
859  break;
860  case ELF::R_BPF_64_64: {
861  write(isBE, Section.getAddressWithOffset(Offset), Value + Addend);
862  DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
863  << format("%p\n", Section.getAddressWithOffset(Offset)));
864  break;
865  }
866  case ELF::R_BPF_64_32: {
867  Value += Addend;
868  assert(Value <= UINT32_MAX);
869  write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value));
870  DEBUG(dbgs() << "Writing " << format("%p", Value) << " at "
871  << format("%p\n", Section.getAddressWithOffset(Offset)));
872  break;
873  }
874  }
875 }
876 
877 // The target location for the relocation is described by RE.SectionID and
878 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
879 // SectionEntry has three members describing its location.
880 // SectionEntry::Address is the address at which the section has been loaded
881 // into memory in the current (host) process. SectionEntry::LoadAddress is the
882 // address that the section will have in the target process.
883 // SectionEntry::ObjAddress is the address of the bits for this section in the
884 // original emitted object image (also in the current address space).
885 //
886 // Relocations will be applied as if the section were loaded at
887 // SectionEntry::LoadAddress, but they will be applied at an address based
888 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to
889 // Target memory contents if they are required for value calculations.
890 //
891 // The Value parameter here is the load address of the symbol for the
892 // relocation to be applied. For relocations which refer to symbols in the
893 // current object Value will be the LoadAddress of the section in which
894 // the symbol resides (RE.Addend provides additional information about the
895 // symbol location). For external symbols, Value will be the address of the
896 // symbol in the target address space.
897 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
898  uint64_t Value) {
899  const SectionEntry &Section = Sections[RE.SectionID];
900  return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
901  RE.SymOffset, RE.SectionID);
902 }
903 
904 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
905  uint64_t Offset, uint64_t Value,
906  uint32_t Type, int64_t Addend,
907  uint64_t SymOffset, SID SectionID) {
908  switch (Arch) {
909  case Triple::x86_64:
910  resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset);
911  break;
912  case Triple::x86:
913  resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
914  (uint32_t)(Addend & 0xffffffffL));
915  break;
916  case Triple::aarch64:
917  case Triple::aarch64_be:
918  resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
919  break;
920  case Triple::arm: // Fall through.
921  case Triple::armeb:
922  case Triple::thumb:
923  case Triple::thumbeb:
924  resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
925  (uint32_t)(Addend & 0xffffffffL));
926  break;
927  case Triple::ppc:
928  resolvePPC32Relocation(Section, Offset, Value, Type, Addend);
929  break;
930  case Triple::ppc64: // Fall through.
931  case Triple::ppc64le:
932  resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
933  break;
934  case Triple::systemz:
935  resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
936  break;
937  case Triple::bpfel:
938  case Triple::bpfeb:
939  resolveBPFRelocation(Section, Offset, Value, Type, Addend);
940  break;
941  default:
942  llvm_unreachable("Unsupported CPU type!");
943  }
944 }
945 
946 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const {
947  return (void *)(Sections[SectionID].getObjAddress() + Offset);
948 }
949 
950 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) {
951  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
952  if (Value.SymbolName)
954  else
956 }
957 
958 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType,
959  bool IsLocal) const {
960  switch (RelType) {
961  case ELF::R_MICROMIPS_GOT16:
962  if (IsLocal)
963  return ELF::R_MICROMIPS_LO16;
964  break;
965  case ELF::R_MICROMIPS_HI16:
966  return ELF::R_MICROMIPS_LO16;
967  case ELF::R_MIPS_GOT16:
968  if (IsLocal)
969  return ELF::R_MIPS_LO16;
970  break;
971  case ELF::R_MIPS_HI16:
972  return ELF::R_MIPS_LO16;
973  case ELF::R_MIPS_PCHI16:
974  return ELF::R_MIPS_PCLO16;
975  default:
976  break;
977  }
978  return ELF::R_MIPS_NONE;
979 }
980 
981 // Sometimes we don't need to create thunk for a branch.
982 // This typically happens when branch target is located
983 // in the same object file. In such case target is either
984 // a weak symbol or symbol in a different executable section.
985 // This function checks if branch target is located in the
986 // same object file and if distance between source and target
987 // fits R_AARCH64_CALL26 relocation. If both conditions are
988 // met, it emits direct jump to the target and returns true.
989 // Otherwise false is returned and thunk is created.
990 bool RuntimeDyldELF::resolveAArch64ShortBranch(
991  unsigned SectionID, relocation_iterator RelI,
992  const RelocationValueRef &Value) {
993  uint64_t Address;
994  if (Value.SymbolName) {
995  auto Loc = GlobalSymbolTable.find(Value.SymbolName);
996 
997  // Don't create direct branch for external symbols.
998  if (Loc == GlobalSymbolTable.end())
999  return false;
1000 
1001  const auto &SymInfo = Loc->second;
1002  Address =
1003  uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset(
1004  SymInfo.getOffset()));
1005  } else {
1006  Address = uint64_t(Sections[Value.SectionID].getLoadAddress());
1007  }
1008  uint64_t Offset = RelI->getOffset();
1009  uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset);
1010 
1011  // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27
1012  // If distance between source and target is out of range then we should
1013  // create thunk.
1014  if (!isInt<28>(Address + Value.Addend - SourceAddress))
1015  return false;
1016 
1017  resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(),
1018  Value.Addend);
1019 
1020  return true;
1021 }
1022 
1023 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID,
1024  const RelocationValueRef &Value,
1025  relocation_iterator RelI,
1026  StubMap &Stubs) {
1027 
1028  DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
1029  SectionEntry &Section = Sections[SectionID];
1030 
1031  uint64_t Offset = RelI->getOffset();
1032  unsigned RelType = RelI->getType();
1033  // Look for an existing stub.
1034  StubMap::const_iterator i = Stubs.find(Value);
1035  if (i != Stubs.end()) {
1036  resolveRelocation(Section, Offset,
1037  (uint64_t)Section.getAddressWithOffset(i->second),
1038  RelType, 0);
1039  DEBUG(dbgs() << " Stub function found\n");
1040  } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) {
1041  // Create a new stub function.
1042  DEBUG(dbgs() << " Create a new stub function\n");
1043  Stubs[Value] = Section.getStubOffset();
1044  uint8_t *StubTargetAddr = createStubFunction(
1045  Section.getAddressWithOffset(Section.getStubOffset()));
1046 
1047  RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(),
1048  ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
1049  RelocationEntry REmovk_g2(SectionID,
1050  StubTargetAddr - Section.getAddress() + 4,
1051  ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
1052  RelocationEntry REmovk_g1(SectionID,
1053  StubTargetAddr - Section.getAddress() + 8,
1054  ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
1055  RelocationEntry REmovk_g0(SectionID,
1056  StubTargetAddr - Section.getAddress() + 12,
1057  ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
1058 
1059  if (Value.SymbolName) {
1060  addRelocationForSymbol(REmovz_g3, Value.SymbolName);
1061  addRelocationForSymbol(REmovk_g2, Value.SymbolName);
1062  addRelocationForSymbol(REmovk_g1, Value.SymbolName);
1063  addRelocationForSymbol(REmovk_g0, Value.SymbolName);
1064  } else {
1065  addRelocationForSection(REmovz_g3, Value.SectionID);
1066  addRelocationForSection(REmovk_g2, Value.SectionID);
1067  addRelocationForSection(REmovk_g1, Value.SectionID);
1068  addRelocationForSection(REmovk_g0, Value.SectionID);
1069  }
1070  resolveRelocation(Section, Offset,
1071  reinterpret_cast<uint64_t>(Section.getAddressWithOffset(
1072  Section.getStubOffset())),
1073  RelType, 0);
1074  Section.advanceStubOffset(getMaxStubSize());
1075  }
1076 }
1077 
1080  unsigned SectionID, relocation_iterator RelI, const ObjectFile &O,
1081  ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) {
1082  const auto &Obj = cast<ELFObjectFileBase>(O);
1083  uint64_t RelType = RelI->getType();
1084  int64_t Addend = 0;
1085  if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend())
1086  Addend = *AddendOrErr;
1087  else
1088  consumeError(AddendOrErr.takeError());
1089  elf_symbol_iterator Symbol = RelI->getSymbol();
1090 
1091  // Obtain the symbol name which is referenced in the relocation
1092  StringRef TargetName;
1093  if (Symbol != Obj.symbol_end()) {
1094  if (auto TargetNameOrErr = Symbol->getName())
1095  TargetName = *TargetNameOrErr;
1096  else
1097  return TargetNameOrErr.takeError();
1098  }
1099  DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend
1100  << " TargetName: " << TargetName << "\n");
1101  RelocationValueRef Value;
1102  // First search for the symbol in the local symbol table
1103  SymbolRef::Type SymType = SymbolRef::ST_Unknown;
1104 
1105  // Search for the symbol in the global symbol table
1107  if (Symbol != Obj.symbol_end()) {
1108  gsi = GlobalSymbolTable.find(TargetName.data());
1109  Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType();
1110  if (!SymTypeOrErr) {
1111  std::string Buf;
1112  raw_string_ostream OS(Buf);
1113  logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, "");
1114  OS.flush();
1115  report_fatal_error(Buf);
1116  }
1117  SymType = *SymTypeOrErr;
1118  }
1119  if (gsi != GlobalSymbolTable.end()) {
1120  const auto &SymInfo = gsi->second;
1121  Value.SectionID = SymInfo.getSectionID();
1122  Value.Offset = SymInfo.getOffset();
1123  Value.Addend = SymInfo.getOffset() + Addend;
1124  } else {
1125  switch (SymType) {
1126  case SymbolRef::ST_Debug: {
1127  // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
1128  // and can be changed by another developers. Maybe best way is add
1129  // a new symbol type ST_Section to SymbolRef and use it.
1130  auto SectionOrErr = Symbol->getSection();
1131  if (!SectionOrErr) {
1132  std::string Buf;
1133  raw_string_ostream OS(Buf);
1134  logAllUnhandledErrors(SectionOrErr.takeError(), OS, "");
1135  OS.flush();
1136  report_fatal_error(Buf);
1137  }
1138  section_iterator si = *SectionOrErr;
1139  if (si == Obj.section_end())
1140  llvm_unreachable("Symbol section not found, bad object file format!");
1141  DEBUG(dbgs() << "\t\tThis is section symbol\n");
1142  bool isCode = si->isText();
1143  if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode,
1144  ObjSectionToID))
1145  Value.SectionID = *SectionIDOrErr;
1146  else
1147  return SectionIDOrErr.takeError();
1148  Value.Addend = Addend;
1149  break;
1150  }
1151  case SymbolRef::ST_Data:
1152  case SymbolRef::ST_Function:
1153  case SymbolRef::ST_Unknown: {
1154  Value.SymbolName = TargetName.data();
1155  Value.Addend = Addend;
1156 
1157  // Absolute relocations will have a zero symbol ID (STN_UNDEF), which
1158  // will manifest here as a NULL symbol name.
1159  // We can set this as a valid (but empty) symbol name, and rely
1160  // on addRelocationForSymbol to handle this.
1161  if (!Value.SymbolName)
1162  Value.SymbolName = "";
1163  break;
1164  }
1165  default:
1166  llvm_unreachable("Unresolved symbol type!");
1167  break;
1168  }
1169  }
1170 
1171  uint64_t Offset = RelI->getOffset();
1172 
1173  DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset
1174  << "\n");
1175  if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) {
1176  if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) {
1177  resolveAArch64Branch(SectionID, Value, RelI, Stubs);
1178  } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) {
1179  // Craete new GOT entry or find existing one. If GOT entry is
1180  // to be created, then we also emit ABS64 relocation for it.
1181  uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64);
1182  resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1183  ELF::R_AARCH64_ADR_PREL_PG_HI21);
1184 
1185  } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) {
1186  uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64);
1187  resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1188  ELF::R_AARCH64_LDST64_ABS_LO12_NC);
1189  } else {
1190  processSimpleRelocation(SectionID, Offset, RelType, Value);
1191  }
1192  } else if (Arch == Triple::arm) {
1193  if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL ||
1194  RelType == ELF::R_ARM_JUMP24) {
1195  // This is an ARM branch relocation, need to use a stub function.
1196  DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n");
1197  SectionEntry &Section = Sections[SectionID];
1198 
1199  // Look for an existing stub.
1200  StubMap::const_iterator i = Stubs.find(Value);
1201  if (i != Stubs.end()) {
1202  resolveRelocation(
1203  Section, Offset,
1204  reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)),
1205  RelType, 0);
1206  DEBUG(dbgs() << " Stub function found\n");
1207  } else {
1208  // Create a new stub function.
1209  DEBUG(dbgs() << " Create a new stub function\n");
1210  Stubs[Value] = Section.getStubOffset();
1211  uint8_t *StubTargetAddr = createStubFunction(
1212  Section.getAddressWithOffset(Section.getStubOffset()));
1213  RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1214  ELF::R_ARM_ABS32, Value.Addend);
1215  if (Value.SymbolName)
1217  else
1219 
1220  resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1221  Section.getAddressWithOffset(
1222  Section.getStubOffset())),
1223  RelType, 0);
1224  Section.advanceStubOffset(getMaxStubSize());
1225  }
1226  } else {
1227  uint32_t *Placeholder =
1228  reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset));
1229  if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 ||
1230  RelType == ELF::R_ARM_ABS32) {
1231  Value.Addend += *Placeholder;
1232  } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) {
1233  // See ELF for ARM documentation
1234  Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12));
1235  }
1236  processSimpleRelocation(SectionID, Offset, RelType, Value);
1237  }
1238  } else if (IsMipsO32ABI) {
1239  uint8_t *Placeholder = reinterpret_cast<uint8_t *>(
1240  computePlaceholderAddress(SectionID, Offset));
1241  uint32_t Opcode = readBytesUnaligned(Placeholder, 4);
1242  if (RelType == ELF::R_MIPS_26) {
1243  // This is an Mips branch relocation, need to use a stub function.
1244  DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1245  SectionEntry &Section = Sections[SectionID];
1246 
1247  // Extract the addend from the instruction.
1248  // We shift up by two since the Value will be down shifted again
1249  // when applying the relocation.
1250  uint32_t Addend = (Opcode & 0x03ffffff) << 2;
1251 
1252  Value.Addend += Addend;
1253 
1254  // Look up for existing stub.
1255  StubMap::const_iterator i = Stubs.find(Value);
1256  if (i != Stubs.end()) {
1257  RelocationEntry RE(SectionID, Offset, RelType, i->second);
1258  addRelocationForSection(RE, SectionID);
1259  DEBUG(dbgs() << " Stub function found\n");
1260  } else {
1261  // Create a new stub function.
1262  DEBUG(dbgs() << " Create a new stub function\n");
1263  Stubs[Value] = Section.getStubOffset();
1264 
1265  unsigned AbiVariant = Obj.getPlatformFlags();
1266 
1267  uint8_t *StubTargetAddr = createStubFunction(
1268  Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
1269 
1270  // Creating Hi and Lo relocations for the filled stub instructions.
1271  RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
1272  ELF::R_MIPS_HI16, Value.Addend);
1273  RelocationEntry RELo(SectionID,
1274  StubTargetAddr - Section.getAddress() + 4,
1275  ELF::R_MIPS_LO16, Value.Addend);
1276 
1277  if (Value.SymbolName) {
1278  addRelocationForSymbol(REHi, Value.SymbolName);
1279  addRelocationForSymbol(RELo, Value.SymbolName);
1280  } else {
1281  addRelocationForSection(REHi, Value.SectionID);
1282  addRelocationForSection(RELo, Value.SectionID);
1283  }
1284 
1285  RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
1286  addRelocationForSection(RE, SectionID);
1287  Section.advanceStubOffset(getMaxStubSize());
1288  }
1289  } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) {
1290  int64_t Addend = (Opcode & 0x0000ffff) << 16;
1291  RelocationEntry RE(SectionID, Offset, RelType, Addend);
1292  PendingRelocs.push_back(std::make_pair(Value, RE));
1293  } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) {
1294  int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff);
1295  for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) {
1296  const RelocationValueRef &MatchingValue = I->first;
1297  RelocationEntry &Reloc = I->second;
1298  if (MatchingValue == Value &&
1299  RelType == getMatchingLoRelocation(Reloc.RelType) &&
1300  SectionID == Reloc.SectionID) {
1301  Reloc.Addend += Addend;
1302  if (Value.SymbolName)
1303  addRelocationForSymbol(Reloc, Value.SymbolName);
1304  else
1305  addRelocationForSection(Reloc, Value.SectionID);
1306  I = PendingRelocs.erase(I);
1307  } else
1308  ++I;
1309  }
1310  RelocationEntry RE(SectionID, Offset, RelType, Addend);
1311  if (Value.SymbolName)
1313  else
1315  } else {
1316  if (RelType == ELF::R_MIPS_32)
1317  Value.Addend += Opcode;
1318  else if (RelType == ELF::R_MIPS_PC16)
1319  Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2);
1320  else if (RelType == ELF::R_MIPS_PC19_S2)
1321  Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2);
1322  else if (RelType == ELF::R_MIPS_PC21_S2)
1323  Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2);
1324  else if (RelType == ELF::R_MIPS_PC26_S2)
1325  Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2);
1326  processSimpleRelocation(SectionID, Offset, RelType, Value);
1327  }
1328  } else if (IsMipsN32ABI || IsMipsN64ABI) {
1329  uint32_t r_type = RelType & 0xff;
1330  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1331  if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE
1332  || r_type == ELF::R_MIPS_GOT_DISP) {
1333  StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName);
1334  if (i != GOTSymbolOffsets.end())
1335  RE.SymOffset = i->second;
1336  else {
1337  RE.SymOffset = allocateGOTEntries(1);
1338  GOTSymbolOffsets[TargetName] = RE.SymOffset;
1339  }
1340  if (Value.SymbolName)
1342  else
1344  } else if (RelType == ELF::R_MIPS_26) {
1345  // This is an Mips branch relocation, need to use a stub function.
1346  DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1347  SectionEntry &Section = Sections[SectionID];
1348 
1349  // Look up for existing stub.
1350  StubMap::const_iterator i = Stubs.find(Value);
1351  if (i != Stubs.end()) {
1352  RelocationEntry RE(SectionID, Offset, RelType, i->second);
1353  addRelocationForSection(RE, SectionID);
1354  DEBUG(dbgs() << " Stub function found\n");
1355  } else {
1356  // Create a new stub function.
1357  DEBUG(dbgs() << " Create a new stub function\n");
1358  Stubs[Value] = Section.getStubOffset();
1359 
1360  unsigned AbiVariant = Obj.getPlatformFlags();
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 = Obj.getPlatformFlags();
1418  AbiVariant &= ELF::EF_PPC64_ABI;
1419  // A PPC branch relocation will need a stub function if the target is
1420  // an external symbol (either Value.SymbolName is set, or SymType is
1421  // Symbol::ST_Unknown) or if the target address is not within the
1422  // signed 24-bits branch address.
1423  SectionEntry &Section = Sections[SectionID];
1424  uint8_t *Target = Section.getAddressWithOffset(Offset);
1425  bool RangeOverflow = false;
1426  if (!Value.SymbolName && SymType != SymbolRef::ST_Unknown) {
1427  if (AbiVariant != 2) {
1428  // In the ELFv1 ABI, a function call may point to the .opd entry,
1429  // so the final symbol value is calculated based on the relocation
1430  // values in the .opd section.
1431  if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value))
1432  return std::move(Err);
1433  } else {
1434  // In the ELFv2 ABI, a function symbol may provide a local entry
1435  // point, which must be used for direct calls.
1436  uint8_t SymOther = Symbol->getOther();
1437  Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther);
1438  }
1439  uint8_t *RelocTarget =
1440  Sections[Value.SectionID].getAddressWithOffset(Value.Addend);
1441  int64_t delta = static_cast<int64_t>(Target - RelocTarget);
1442  // If it is within 26-bits branch range, just set the branch target
1443  if (SignExtend64<26>(delta) == delta) {
1444  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1446  } else {
1447  RangeOverflow = true;
1448  }
1449  }
1450  if (Value.SymbolName || SymType == SymbolRef::ST_Unknown ||
1451  RangeOverflow) {
1452  // It is an external symbol (either Value.SymbolName is set, or
1453  // SymType is SymbolRef::ST_Unknown) or out of range.
1454  StubMap::const_iterator i = Stubs.find(Value);
1455  if (i != Stubs.end()) {
1456  // Symbol function stub already created, just relocate to it
1457  resolveRelocation(Section, Offset,
1458  reinterpret_cast<uint64_t>(
1459  Section.getAddressWithOffset(i->second)),
1460  RelType, 0);
1461  DEBUG(dbgs() << " Stub function found\n");
1462  } else {
1463  // Create a new stub function.
1464  DEBUG(dbgs() << " Create a new stub function\n");
1465  Stubs[Value] = Section.getStubOffset();
1466  uint8_t *StubTargetAddr = createStubFunction(
1467  Section.getAddressWithOffset(Section.getStubOffset()),
1468  AbiVariant);
1469  RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1470  ELF::R_PPC64_ADDR64, Value.Addend);
1471 
1472  // Generates the 64-bits address loads as exemplified in section
1473  // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to
1474  // apply to the low part of the instructions, so we have to update
1475  // the offset according to the target endianness.
1476  uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress();
1477  if (!IsTargetLittleEndian)
1478  StubRelocOffset += 2;
1479 
1480  RelocationEntry REhst(SectionID, StubRelocOffset + 0,
1481  ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
1482  RelocationEntry REhr(SectionID, StubRelocOffset + 4,
1483  ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
1484  RelocationEntry REh(SectionID, StubRelocOffset + 12,
1485  ELF::R_PPC64_ADDR16_HI, Value.Addend);
1486  RelocationEntry REl(SectionID, StubRelocOffset + 16,
1487  ELF::R_PPC64_ADDR16_LO, Value.Addend);
1488 
1489  if (Value.SymbolName) {
1490  addRelocationForSymbol(REhst, Value.SymbolName);
1491  addRelocationForSymbol(REhr, Value.SymbolName);
1492  addRelocationForSymbol(REh, Value.SymbolName);
1493  addRelocationForSymbol(REl, Value.SymbolName);
1494  } else {
1495  addRelocationForSection(REhst, Value.SectionID);
1496  addRelocationForSection(REhr, Value.SectionID);
1497  addRelocationForSection(REh, Value.SectionID);
1498  addRelocationForSection(REl, Value.SectionID);
1499  }
1500 
1501  resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1502  Section.getAddressWithOffset(
1503  Section.getStubOffset())),
1504  RelType, 0);
1505  Section.advanceStubOffset(getMaxStubSize());
1506  }
1507  if (Value.SymbolName || SymType == SymbolRef::ST_Unknown) {
1508  // Restore the TOC for external calls
1509  if (AbiVariant == 2)
1510  writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1)
1511  else
1512  writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1)
1513  }
1514  }
1515  } else if (RelType == ELF::R_PPC64_TOC16 ||
1516  RelType == ELF::R_PPC64_TOC16_DS ||
1517  RelType == ELF::R_PPC64_TOC16_LO ||
1518  RelType == ELF::R_PPC64_TOC16_LO_DS ||
1519  RelType == ELF::R_PPC64_TOC16_HI ||
1520  RelType == ELF::R_PPC64_TOC16_HA) {
1521  // These relocations are supposed to subtract the TOC address from
1522  // the final value. This does not fit cleanly into the RuntimeDyld
1523  // scheme, since there may be *two* sections involved in determining
1524  // the relocation value (the section of the symbol referred to by the
1525  // relocation, and the TOC section associated with the current module).
1526  //
1527  // Fortunately, these relocations are currently only ever generated
1528  // referring to symbols that themselves reside in the TOC, which means
1529  // that the two sections are actually the same. Thus they cancel out
1530  // and we can immediately resolve the relocation right now.
1531  switch (RelType) {
1532  case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break;
1533  case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break;
1534  case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break;
1535  case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break;
1536  case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break;
1537  case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break;
1538  default: llvm_unreachable("Wrong relocation type.");
1539  }
1540 
1541  RelocationValueRef TOCValue;
1542  if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue))
1543  return std::move(Err);
1544  if (Value.SymbolName || Value.SectionID != TOCValue.SectionID)
1545  llvm_unreachable("Unsupported TOC relocation.");
1546  Value.Addend -= TOCValue.Addend;
1547  resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0);
1548  } else {
1549  // There are two ways to refer to the TOC address directly: either
1550  // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are
1551  // ignored), or via any relocation that refers to the magic ".TOC."
1552  // symbols (in which case the addend is respected).
1553  if (RelType == ELF::R_PPC64_TOC) {
1554  RelType = ELF::R_PPC64_ADDR64;
1555  if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1556  return std::move(Err);
1557  } else if (TargetName == ".TOC.") {
1558  if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1559  return std::move(Err);
1560  Value.Addend += Addend;
1561  }
1562 
1563  RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1564 
1565  if (Value.SymbolName)
1567  else
1569  }
1570  } else if (Arch == Triple::systemz &&
1571  (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) {
1572  // Create function stubs for both PLT and GOT references, regardless of
1573  // whether the GOT reference is to data or code. The stub contains the
1574  // full address of the symbol, as needed by GOT references, and the
1575  // executable part only adds an overhead of 8 bytes.
1576  //
1577  // We could try to conserve space by allocating the code and data
1578  // parts of the stub separately. However, as things stand, we allocate
1579  // a stub for every relocation, so using a GOT in JIT code should be
1580  // no less space efficient than using an explicit constant pool.
1581  DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1582  SectionEntry &Section = Sections[SectionID];
1583 
1584  // Look for an existing stub.
1585  StubMap::const_iterator i = Stubs.find(Value);
1586  uintptr_t StubAddress;
1587  if (i != Stubs.end()) {
1588  StubAddress = uintptr_t(Section.getAddressWithOffset(i->second));
1589  DEBUG(dbgs() << " Stub function found\n");
1590  } else {
1591  // Create a new stub function.
1592  DEBUG(dbgs() << " Create a new stub function\n");
1593 
1594  uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1595  uintptr_t StubAlignment = getStubAlignment();
1596  StubAddress =
1597  (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1598  -StubAlignment;
1599  unsigned StubOffset = StubAddress - BaseAddress;
1600 
1601  Stubs[Value] = StubOffset;
1602  createStubFunction((uint8_t *)StubAddress);
1603  RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64,
1604  Value.Offset);
1605  if (Value.SymbolName)
1607  else
1609  Section.advanceStubOffset(getMaxStubSize());
1610  }
1611 
1612  if (RelType == ELF::R_390_GOTENT)
1613  resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL,
1614  Addend);
1615  else
1616  resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1617  } else if (Arch == Triple::x86_64) {
1618  if (RelType == ELF::R_X86_64_PLT32) {
1619  // The way the PLT relocations normally work is that the linker allocates
1620  // the
1621  // PLT and this relocation makes a PC-relative call into the PLT. The PLT
1622  // entry will then jump to an address provided by the GOT. On first call,
1623  // the
1624  // GOT address will point back into PLT code that resolves the symbol. After
1625  // the first call, the GOT entry points to the actual function.
1626  //
1627  // For local functions we're ignoring all of that here and just replacing
1628  // the PLT32 relocation type with PC32, which will translate the relocation
1629  // into a PC-relative call directly to the function. For external symbols we
1630  // can't be sure the function will be within 2^32 bytes of the call site, so
1631  // we need to create a stub, which calls into the GOT. This case is
1632  // equivalent to the usual PLT implementation except that we use the stub
1633  // mechanism in RuntimeDyld (which puts stubs at the end of the section)
1634  // rather than allocating a PLT section.
1635  if (Value.SymbolName) {
1636  // This is a call to an external function.
1637  // Look for an existing stub.
1638  SectionEntry &Section = Sections[SectionID];
1639  StubMap::const_iterator i = Stubs.find(Value);
1640  uintptr_t StubAddress;
1641  if (i != Stubs.end()) {
1642  StubAddress = uintptr_t(Section.getAddress()) + i->second;
1643  DEBUG(dbgs() << " Stub function found\n");
1644  } else {
1645  // Create a new stub function (equivalent to a PLT entry).
1646  DEBUG(dbgs() << " Create a new stub function\n");
1647 
1648  uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1649  uintptr_t StubAlignment = getStubAlignment();
1650  StubAddress =
1651  (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1652  -StubAlignment;
1653  unsigned StubOffset = StubAddress - BaseAddress;
1654  Stubs[Value] = StubOffset;
1655  createStubFunction((uint8_t *)StubAddress);
1656 
1657  // Bump our stub offset counter
1658  Section.advanceStubOffset(getMaxStubSize());
1659 
1660  // Allocate a GOT Entry
1661  uint64_t GOTOffset = allocateGOTEntries(1);
1662 
1663  // The load of the GOT address has an addend of -4
1664  resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4,
1665  ELF::R_X86_64_PC32);
1666 
1667  // Fill in the value of the symbol we're targeting into the GOT
1669  computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64),
1670  Value.SymbolName);
1671  }
1672 
1673  // Make the target call a call into the stub table.
1674  resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32,
1675  Addend);
1676  } else {
1677  RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend,
1678  Value.Offset);
1680  }
1681  } else if (RelType == ELF::R_X86_64_GOTPCREL ||
1682  RelType == ELF::R_X86_64_GOTPCRELX ||
1683  RelType == ELF::R_X86_64_REX_GOTPCRELX) {
1684  uint64_t GOTOffset = allocateGOTEntries(1);
1685  resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1686  ELF::R_X86_64_PC32);
1687 
1688  // Fill in the value of the symbol we're targeting into the GOT
1689  RelocationEntry RE =
1690  computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64);
1691  if (Value.SymbolName)
1693  else
1695  } else if (RelType == ELF::R_X86_64_PC32) {
1696  Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1697  processSimpleRelocation(SectionID, Offset, RelType, Value);
1698  } else if (RelType == ELF::R_X86_64_PC64) {
1699  Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset));
1700  processSimpleRelocation(SectionID, Offset, RelType, Value);
1701  } else {
1702  processSimpleRelocation(SectionID, Offset, RelType, Value);
1703  }
1704  } else {
1705  if (Arch == Triple::x86) {
1706  Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1707  }
1708  processSimpleRelocation(SectionID, Offset, RelType, Value);
1709  }
1710  return ++RelI;
1711 }
1712 
1714  // We don't use the GOT in all of these cases, but it's essentially free
1715  // to put them all here.
1716  size_t Result = 0;
1717  switch (Arch) {
1718  case Triple::x86_64:
1719  case Triple::aarch64:
1720  case Triple::aarch64_be:
1721  case Triple::ppc64:
1722  case Triple::ppc64le:
1723  case Triple::systemz:
1724  Result = sizeof(uint64_t);
1725  break;
1726  case Triple::x86:
1727  case Triple::arm:
1728  case Triple::thumb:
1729  Result = sizeof(uint32_t);
1730  break;
1731  case Triple::mips:
1732  case Triple::mipsel:
1733  case Triple::mips64:
1734  case Triple::mips64el:
1735  if (IsMipsO32ABI || IsMipsN32ABI)
1736  Result = sizeof(uint32_t);
1737  else if (IsMipsN64ABI)
1738  Result = sizeof(uint64_t);
1739  else
1740  llvm_unreachable("Mips ABI not handled");
1741  break;
1742  default:
1743  llvm_unreachable("Unsupported CPU type!");
1744  }
1745  return Result;
1746 }
1747 
1748 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) {
1749  if (GOTSectionID == 0) {
1750  GOTSectionID = Sections.size();
1751  // Reserve a section id. We'll allocate the section later
1752  // once we know the total size
1753  Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0));
1754  }
1755  uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize();
1756  CurrentGOTIndex += no;
1757  return StartOffset;
1758 }
1759 
1760 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value,
1761  unsigned GOTRelType) {
1762  auto E = GOTOffsetMap.insert({Value, 0});
1763  if (E.second) {
1764  uint64_t GOTOffset = allocateGOTEntries(1);
1765 
1766  // Create relocation for newly created GOT entry
1767  RelocationEntry RE =
1768  computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType);
1769  if (Value.SymbolName)
1771  else
1773 
1774  E.first->second = GOTOffset;
1775  }
1776 
1777  return E.first->second;
1778 }
1779 
1780 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID,
1781  uint64_t Offset,
1782  uint64_t GOTOffset,
1783  uint32_t Type) {
1784  // Fill in the relative address of the GOT Entry into the stub
1785  RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset);
1786  addRelocationForSection(GOTRE, GOTSectionID);
1787 }
1788 
1789 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset,
1790  uint64_t SymbolOffset,
1791  uint32_t Type) {
1792  return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset);
1793 }
1794 
1796  ObjSectionToIDMap &SectionMap) {
1797  if (IsMipsO32ABI)
1798  if (!PendingRelocs.empty())
1799  return make_error<RuntimeDyldError>("Can't find matching LO16 reloc");
1800 
1801  // If necessary, allocate the global offset table
1802  if (GOTSectionID != 0) {
1803  // Allocate memory for the section
1804  size_t TotalSize = CurrentGOTIndex * getGOTEntrySize();
1805  uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(),
1806  GOTSectionID, ".got", false);
1807  if (!Addr)
1808  return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!");
1809 
1810  Sections[GOTSectionID] =
1811  SectionEntry(".got", Addr, TotalSize, TotalSize, 0);
1812 
1813  if (Checker)
1814  Checker->registerSection(Obj.getFileName(), GOTSectionID);
1815 
1816  // For now, initialize all GOT entries to zero. We'll fill them in as
1817  // needed when GOT-based relocations are applied.
1818  memset(Addr, 0, TotalSize);
1819  if (IsMipsN32ABI || IsMipsN64ABI) {
1820  // To correctly resolve Mips GOT relocations, we need a mapping from
1821  // object's sections to GOTs.
1822  for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
1823  SI != SE; ++SI) {
1824  if (SI->relocation_begin() != SI->relocation_end()) {
1825  section_iterator RelocatedSection = SI->getRelocatedSection();
1826  ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection);
1827  assert (i != SectionMap.end());
1828  SectionToGOTMap[i->second] = GOTSectionID;
1829  }
1830  }
1831  GOTSymbolOffsets.clear();
1832  }
1833  }
1834 
1835  // Look for and record the EH frame section.
1836  ObjSectionToIDMap::iterator i, e;
1837  for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
1838  const SectionRef &Section = i->first;
1839  StringRef Name;
1840  Section.getName(Name);
1841  if (Name == ".eh_frame") {
1842  UnregisteredEHFrameSections.push_back(i->second);
1843  break;
1844  }
1845  }
1846 
1847  GOTSectionID = 0;
1848  CurrentGOTIndex = 0;
1849 
1850  return Error::success();
1851 }
1852 
1854  return Obj.isELF();
1855 }
1856 
1857 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const {
1858  unsigned RelTy = R.getType();
1860  return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE ||
1861  RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC;
1862 
1863  if (Arch == Triple::x86_64)
1864  return RelTy == ELF::R_X86_64_GOTPCREL ||
1865  RelTy == ELF::R_X86_64_GOTPCRELX ||
1866  RelTy == ELF::R_X86_64_REX_GOTPCRELX;
1867  return false;
1868 }
1869 
1870 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const {
1871  if (Arch != Triple::x86_64)
1872  return true; // Conservative answer
1873 
1874  switch (R.getType()) {
1875  default:
1876  return true; // Conservative answer
1877 
1878 
1879  case ELF::R_X86_64_GOTPCREL:
1880  case ELF::R_X86_64_GOTPCRELX:
1881  case ELF::R_X86_64_REX_GOTPCRELX:
1882  case ELF::R_X86_64_PC32:
1883  case ELF::R_X86_64_PC64:
1884  case ELF::R_X86_64_64:
1885  // We know that these reloation types won't need a stub function. This list
1886  // can be extended as needed.
1887  return false;
1888  }
1889 }
1890 
1891 } // 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:335
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:274
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:358
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 interface.
Definition: JITSymbol.h:286
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:457
void consumeError(Error Err)
Consume a Error without doing anything.
Definition: Error.h:962
uint64_t getType() const
Definition: ObjectFile.h:487
#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:362
int64_t Addend
Addend - the relocation addend encoded in the instruction itself.
std::error_code getName(StringRef &Result) const
Definition: ObjectFile.h:393
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:132
StringMap - This is an unconventional map that is specialized for handling keys that are "strings"...
Definition: StringMap.h:222
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: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:94
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
iterator end()
Definition: StringMap.h:320
This is a value type class that represents a single section in the list of sections in the object fil...
Definition: ObjectFile.h:81