RuntimeDyldELF.cpp revision 167957fa095bc7200b908e6e142be3e604bcfeea 
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#define DEBUG_TYPE "dyld"
15#include "RuntimeDyldELF.h"
16#include "JITRegistrar.h"
17#include "ObjectImageCommon.h"
18#include "llvm/ADT/IntervalMap.h"
19#include "llvm/ADT/OwningPtr.h"
20#include "llvm/ADT/STLExtras.h"
21#include "llvm/ADT/StringRef.h"
22#include "llvm/ADT/Triple.h"
23#include "llvm/ExecutionEngine/ObjectBuffer.h"
24#include "llvm/ExecutionEngine/ObjectImage.h"
25#include "llvm/Object/ELF.h"
26#include "llvm/Object/ObjectFile.h"
27#include "llvm/Support/ELF.h"
28using namespace llvm;
29using namespace llvm::object;
30
31namespace {
32
33static inline
34error_code check(error_code Err) {
35  if (Err) {
36    report_fatal_error(Err.message());
37  }
38  return Err;
39}
40
41template<class ELFT>
42class DyldELFObject
43  : public ELFObjectFile<ELFT> {
44  LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
45
46  typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
47  typedef Elf_Sym_Impl<ELFT> Elf_Sym;
48  typedef
49    Elf_Rel_Impl<ELFT, false> Elf_Rel;
50  typedef
51    Elf_Rel_Impl<ELFT, true> Elf_Rela;
52
53  typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
54
55  typedef typename ELFDataTypeTypedefHelper<
56          ELFT>::value_type addr_type;
57
58public:
59  DyldELFObject(MemoryBuffer *Wrapper, error_code &ec);
60
61  void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
62  void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr);
63
64  // Methods for type inquiry through isa, cast and dyn_cast
65  static inline bool classof(const Binary *v) {
66    return (isa<ELFObjectFile<ELFT> >(v)
67            && classof(cast<ELFObjectFile
68                <ELFT> >(v)));
69  }
70  static inline bool classof(
71      const ELFObjectFile<ELFT> *v) {
72    return v->isDyldType();
73  }
74};
75
76template<class ELFT>
77class ELFObjectImage : public ObjectImageCommon {
78  protected:
79    DyldELFObject<ELFT> *DyldObj;
80    bool Registered;
81
82  public:
83    ELFObjectImage(ObjectBuffer *Input,
84                 DyldELFObject<ELFT> *Obj)
85    : ObjectImageCommon(Input, Obj),
86      DyldObj(Obj),
87      Registered(false) {}
88
89    virtual ~ELFObjectImage() {
90      if (Registered)
91        deregisterWithDebugger();
92    }
93
94    // Subclasses can override these methods to update the image with loaded
95    // addresses for sections and common symbols
96    virtual void updateSectionAddress(const SectionRef &Sec, uint64_t Addr)
97    {
98      DyldObj->updateSectionAddress(Sec, Addr);
99    }
100
101    virtual void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr)
102    {
103      DyldObj->updateSymbolAddress(Sym, Addr);
104    }
105
106    virtual void registerWithDebugger()
107    {
108      JITRegistrar::getGDBRegistrar().registerObject(*Buffer);
109      Registered = true;
110    }
111    virtual void deregisterWithDebugger()
112    {
113      JITRegistrar::getGDBRegistrar().deregisterObject(*Buffer);
114    }
115};
116
117// The MemoryBuffer passed into this constructor is just a wrapper around the
118// actual memory.  Ultimately, the Binary parent class will take ownership of
119// this MemoryBuffer object but not the underlying memory.
120template<class ELFT>
121DyldELFObject<ELFT>::DyldELFObject(MemoryBuffer *Wrapper, error_code &ec)
122  : ELFObjectFile<ELFT>(Wrapper, ec) {
123  this->isDyldELFObject = true;
124}
125
126template<class ELFT>
127void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
128                                               uint64_t Addr) {
129  DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
130  Elf_Shdr *shdr = const_cast<Elf_Shdr*>(
131                          reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
132
133  // This assumes the address passed in matches the target address bitness
134  // The template-based type cast handles everything else.
135  shdr->sh_addr = static_cast<addr_type>(Addr);
136}
137
138template<class ELFT>
139void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
140                                              uint64_t Addr) {
141
142  Elf_Sym *sym = const_cast<Elf_Sym*>(
143    ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl()));
144
145  // This assumes the address passed in matches the target address bitness
146  // The template-based type cast handles everything else.
147  sym->st_value = static_cast<addr_type>(Addr);
148}
149
150} // namespace
151
152namespace llvm {
153
154StringRef RuntimeDyldELF::getEHFrameSection() {
155  for (int i = 0, e = Sections.size(); i != e; ++i) {
156    if (Sections[i].Name == ".eh_frame")
157      return StringRef((const char*)Sections[i].Address, Sections[i].Size);
158  }
159  return StringRef();
160}
161
162ObjectImage *RuntimeDyldELF::createObjectImage(ObjectBuffer *Buffer) {
163  if (Buffer->getBufferSize() < ELF::EI_NIDENT)
164    llvm_unreachable("Unexpected ELF object size");
165  std::pair<unsigned char, unsigned char> Ident = std::make_pair(
166                         (uint8_t)Buffer->getBufferStart()[ELF::EI_CLASS],
167                         (uint8_t)Buffer->getBufferStart()[ELF::EI_DATA]);
168  error_code ec;
169
170  if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB) {
171    DyldELFObject<ELFType<support::little, 4, false> > *Obj =
172      new DyldELFObject<ELFType<support::little, 4, false> >(
173        Buffer->getMemBuffer(), ec);
174    return new ELFObjectImage<ELFType<support::little, 4, false> >(Buffer, Obj);
175  }
176  else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB) {
177    DyldELFObject<ELFType<support::big, 4, false> > *Obj =
178      new DyldELFObject<ELFType<support::big, 4, false> >(
179        Buffer->getMemBuffer(), ec);
180    return new ELFObjectImage<ELFType<support::big, 4, false> >(Buffer, Obj);
181  }
182  else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB) {
183    DyldELFObject<ELFType<support::big, 8, true> > *Obj =
184      new DyldELFObject<ELFType<support::big, 8, true> >(
185        Buffer->getMemBuffer(), ec);
186    return new ELFObjectImage<ELFType<support::big, 8, true> >(Buffer, Obj);
187  }
188  else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
189    DyldELFObject<ELFType<support::little, 8, true> > *Obj =
190      new DyldELFObject<ELFType<support::little, 8, true> >(
191        Buffer->getMemBuffer(), ec);
192    return new ELFObjectImage<ELFType<support::little, 8, true> >(Buffer, Obj);
193  }
194  else
195    llvm_unreachable("Unexpected ELF format");
196}
197
198RuntimeDyldELF::~RuntimeDyldELF() {
199}
200
201void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
202                                             uint64_t Offset,
203                                             uint64_t Value,
204                                             uint32_t Type,
205                                             int64_t Addend) {
206  switch (Type) {
207  default:
208    llvm_unreachable("Relocation type not implemented yet!");
209  break;
210  case ELF::R_X86_64_64: {
211    uint64_t *Target = reinterpret_cast<uint64_t*>(Section.Address + Offset);
212    *Target = Value + Addend;
213    DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend))
214                 << " at " << format("%p\n",Target));
215    break;
216  }
217  case ELF::R_X86_64_32:
218  case ELF::R_X86_64_32S: {
219    Value += Addend;
220    assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) ||
221           (Type == ELF::R_X86_64_32S &&
222             ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN)));
223    uint32_t TruncatedAddr = (Value & 0xFFFFFFFF);
224    uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
225    *Target = TruncatedAddr;
226    DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr)
227                 << " at " << format("%p\n",Target));
228    break;
229  }
230  case ELF::R_X86_64_PC32: {
231    // Get the placeholder value from the generated object since
232    // a previous relocation attempt may have overwritten the loaded version
233    uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress
234                                                                   + Offset);
235    uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
236    uint64_t  FinalAddress = Section.LoadAddress + Offset;
237    int64_t RealOffset = *Placeholder + Value + Addend - FinalAddress;
238    assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN);
239    int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
240    *Target = TruncOffset;
241    break;
242  }
243  }
244}
245
246void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
247                                          uint64_t Offset,
248                                          uint32_t Value,
249                                          uint32_t Type,
250                                          int32_t Addend) {
251  switch (Type) {
252  case ELF::R_386_32: {
253    // Get the placeholder value from the generated object since
254    // a previous relocation attempt may have overwritten the loaded version
255    uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress
256                                                                   + Offset);
257    uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
258    *Target = *Placeholder + Value + Addend;
259    break;
260  }
261  case ELF::R_386_PC32: {
262    // Get the placeholder value from the generated object since
263    // a previous relocation attempt may have overwritten the loaded version
264    uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress
265                                                                   + Offset);
266    uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
267    uint32_t  FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
268    uint32_t RealOffset = *Placeholder + Value + Addend - FinalAddress;
269    *Target = RealOffset;
270    break;
271    }
272    default:
273      // There are other relocation types, but it appears these are the
274      // only ones currently used by the LLVM ELF object writer
275      llvm_unreachable("Relocation type not implemented yet!");
276      break;
277  }
278}
279
280void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
281                                              uint64_t Offset,
282                                              uint64_t Value,
283                                              uint32_t Type,
284                                              int64_t Addend) {
285  uint32_t *TargetPtr = reinterpret_cast<uint32_t*>(Section.Address + Offset);
286  uint64_t FinalAddress = Section.LoadAddress + Offset;
287
288  DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
289               << format("%llx", Section.Address + Offset)
290               << " FinalAddress: 0x" << format("%llx",FinalAddress)
291               << " Value: 0x" << format("%llx",Value)
292               << " Type: 0x" << format("%x",Type)
293               << " Addend: 0x" << format("%llx",Addend)
294               << "\n");
295
296  switch (Type) {
297  default:
298    llvm_unreachable("Relocation type not implemented yet!");
299    break;
300  case ELF::R_AARCH64_ABS64: {
301    uint64_t *TargetPtr = reinterpret_cast<uint64_t*>(Section.Address + Offset);
302    *TargetPtr = Value + Addend;
303    break;
304  }
305  case ELF::R_AARCH64_PREL32: { // test-shift.ll (.eh_frame)
306    uint64_t Result = Value + Addend - FinalAddress;
307    assert(static_cast<int64_t>(Result) >= INT32_MIN &&
308           static_cast<int64_t>(Result) <= UINT32_MAX);
309    *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU);
310    break;
311  }
312  case ELF::R_AARCH64_CALL26: // fallthrough
313  case ELF::R_AARCH64_JUMP26: {
314    // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
315    // calculation.
316    uint64_t BranchImm = Value + Addend - FinalAddress;
317
318    // "Check that -2^27 <= result < 2^27".
319    assert(-(1LL << 27) <= static_cast<int64_t>(BranchImm) &&
320           static_cast<int64_t>(BranchImm) < (1LL << 27));
321    // Immediate goes in bits 25:0 of B and BL.
322    *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2;
323    break;
324  }
325  case ELF::R_AARCH64_MOVW_UABS_G3: {
326    uint64_t Result = Value + Addend;
327    // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
328    *TargetPtr |= Result >> (48 - 5);
329    // Shift is "lsl #48", in bits 22:21
330    *TargetPtr |= 3 << 21;
331    break;
332  }
333  case ELF::R_AARCH64_MOVW_UABS_G2_NC: {
334    uint64_t Result = Value + Addend;
335    // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
336    *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5));
337    // Shift is "lsl #32", in bits 22:21
338    *TargetPtr |= 2 << 21;
339    break;
340  }
341  case ELF::R_AARCH64_MOVW_UABS_G1_NC: {
342    uint64_t Result = Value + Addend;
343    // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
344    *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5));
345    // Shift is "lsl #16", in bits 22:21
346    *TargetPtr |= 1 << 21;
347    break;
348  }
349  case ELF::R_AARCH64_MOVW_UABS_G0_NC: {
350    uint64_t Result = Value + Addend;
351    // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
352    *TargetPtr |= ((Result & 0xffffU) << 5);
353    // Shift is "lsl #0", in bits 22:21. No action needed.
354    break;
355  }
356  }
357}
358
359void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
360                                          uint64_t Offset,
361                                          uint32_t Value,
362                                          uint32_t Type,
363                                          int32_t Addend) {
364  // TODO: Add Thumb relocations.
365  uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
366  uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
367  Value += Addend;
368
369  DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
370               << Section.Address + Offset
371               << " FinalAddress: " << format("%p",FinalAddress)
372               << " Value: " << format("%x",Value)
373               << " Type: " << format("%x",Type)
374               << " Addend: " << format("%x",Addend)
375               << "\n");
376
377  switch(Type) {
378  default:
379    llvm_unreachable("Not implemented relocation type!");
380
381  // Write a 32bit value to relocation address, taking into account the
382  // implicit addend encoded in the target.
383  case ELF::R_ARM_TARGET1 :
384  case ELF::R_ARM_ABS32 :
385    *TargetPtr += Value;
386    break;
387
388  // Write first 16 bit of 32 bit value to the mov instruction.
389  // Last 4 bit should be shifted.
390  case ELF::R_ARM_MOVW_ABS_NC :
391    // We are not expecting any other addend in the relocation address.
392    // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2
393    // non-contiguous fields.
394    assert((*TargetPtr & 0x000F0FFF) == 0);
395    Value = Value & 0xFFFF;
396    *TargetPtr |= Value & 0xFFF;
397    *TargetPtr |= ((Value >> 12) & 0xF) << 16;
398    break;
399
400  // Write last 16 bit of 32 bit value to the mov instruction.
401  // Last 4 bit should be shifted.
402  case ELF::R_ARM_MOVT_ABS :
403    // We are not expecting any other addend in the relocation address.
404    // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC.
405    assert((*TargetPtr & 0x000F0FFF) == 0);
406    Value = (Value >> 16) & 0xFFFF;
407    *TargetPtr |= Value & 0xFFF;
408    *TargetPtr |= ((Value >> 12) & 0xF) << 16;
409    break;
410
411  // Write 24 bit relative value to the branch instruction.
412  case ELF::R_ARM_PC24 :    // Fall through.
413  case ELF::R_ARM_CALL :    // Fall through.
414  case ELF::R_ARM_JUMP24 :
415    int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
416    RelValue = (RelValue & 0x03FFFFFC) >> 2;
417    *TargetPtr &= 0xFF000000;
418    *TargetPtr |= RelValue;
419    break;
420  }
421}
422
423void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section,
424                                           uint64_t Offset,
425                                           uint32_t Value,
426                                           uint32_t Type,
427                                           int32_t Addend) {
428  uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
429  Value += Addend;
430
431  DEBUG(dbgs() << "resolveMipselocation, LocalAddress: "
432               << Section.Address + Offset
433               << " FinalAddress: "
434               << format("%p",Section.LoadAddress + Offset)
435               << " Value: " << format("%x",Value)
436               << " Type: " << format("%x",Type)
437               << " Addend: " << format("%x",Addend)
438               << "\n");
439
440  switch(Type) {
441  default:
442    llvm_unreachable("Not implemented relocation type!");
443    break;
444  case ELF::R_MIPS_32:
445    *TargetPtr = Value + (*TargetPtr);
446    break;
447  case ELF::R_MIPS_26:
448    *TargetPtr = ((*TargetPtr) & 0xfc000000) | (( Value & 0x0fffffff) >> 2);
449    break;
450  case ELF::R_MIPS_HI16:
451    // Get the higher 16-bits. Also add 1 if bit 15 is 1.
452    Value += ((*TargetPtr) & 0x0000ffff) << 16;
453    *TargetPtr = ((*TargetPtr) & 0xffff0000) |
454                 (((Value + 0x8000) >> 16) & 0xffff);
455    break;
456   case ELF::R_MIPS_LO16:
457    Value += ((*TargetPtr) & 0x0000ffff);
458    *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff);
459    break;
460   }
461}
462
463// Return the .TOC. section address to R_PPC64_TOC relocations.
464uint64_t RuntimeDyldELF::findPPC64TOC() const {
465  // The TOC consists of sections .got, .toc, .tocbss, .plt in that
466  // order. The TOC starts where the first of these sections starts.
467  SectionList::const_iterator it = Sections.begin();
468  SectionList::const_iterator ite = Sections.end();
469  for (; it != ite; ++it) {
470    if (it->Name == ".got" ||
471        it->Name == ".toc" ||
472        it->Name == ".tocbss" ||
473        it->Name == ".plt")
474      break;
475  }
476  if (it == ite) {
477    // This may happen for
478    // * references to TOC base base (sym@toc, .odp relocation) without
479    // a .toc directive.
480    // In this case just use the first section (which is usually
481    // the .odp) since the code won't reference the .toc base
482    // directly.
483    it = Sections.begin();
484  }
485  assert (it != ite);
486  // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
487  // thus permitting a full 64 Kbytes segment.
488  return it->LoadAddress + 0x8000;
489}
490
491// Returns the sections and offset associated with the ODP entry referenced
492// by Symbol.
493void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj,
494                                         ObjSectionToIDMap &LocalSections,
495                                         RelocationValueRef &Rel) {
496  // Get the ELF symbol value (st_value) to compare with Relocation offset in
497  // .opd entries
498
499  error_code err;
500  for (section_iterator si = Obj.begin_sections(),
501     se = Obj.end_sections(); si != se; si.increment(err)) {
502    StringRef SectionName;
503    check(si->getName(SectionName));
504    if (SectionName != ".opd")
505      continue;
506
507    for (relocation_iterator i = si->begin_relocations(),
508         e = si->end_relocations(); i != e;) {
509      check(err);
510
511      // The R_PPC64_ADDR64 relocation indicates the first field
512      // of a .opd entry
513      uint64_t TypeFunc;
514      check(i->getType(TypeFunc));
515      if (TypeFunc != ELF::R_PPC64_ADDR64) {
516        i.increment(err);
517        continue;
518      }
519
520      SymbolRef TargetSymbol;
521      uint64_t TargetSymbolOffset;
522      check(i->getSymbol(TargetSymbol));
523      check(i->getOffset(TargetSymbolOffset));
524      int64_t Addend;
525      check(getELFRelocationAddend(*i, Addend));
526
527      i = i.increment(err);
528      if (i == e)
529        break;
530      check(err);
531
532      // Just check if following relocation is a R_PPC64_TOC
533      uint64_t TypeTOC;
534      check(i->getType(TypeTOC));
535      if (TypeTOC != ELF::R_PPC64_TOC)
536        continue;
537
538      // Finally compares the Symbol value and the target symbol offset
539      // to check if this .opd entry refers to the symbol the relocation
540      // points to.
541      if (Rel.Addend != (intptr_t)TargetSymbolOffset)
542        continue;
543
544      section_iterator tsi(Obj.end_sections());
545      check(TargetSymbol.getSection(tsi));
546      Rel.SectionID = findOrEmitSection(Obj, (*tsi), true, LocalSections);
547      Rel.Addend = (intptr_t)Addend;
548      return;
549    }
550  }
551  llvm_unreachable("Attempting to get address of ODP entry!");
552}
553
554// Relocation masks following the #lo(value), #hi(value), #higher(value),
555// and #highest(value) macros defined in section 4.5.1. Relocation Types
556// in PPC-elf64abi document.
557//
558static inline
559uint16_t applyPPClo (uint64_t value)
560{
561  return value & 0xffff;
562}
563
564static inline
565uint16_t applyPPChi (uint64_t value)
566{
567  return (value >> 16) & 0xffff;
568}
569
570static inline
571uint16_t applyPPChigher (uint64_t value)
572{
573  return (value >> 32) & 0xffff;
574}
575
576static inline
577uint16_t applyPPChighest (uint64_t value)
578{
579  return (value >> 48) & 0xffff;
580}
581
582void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
583                                            uint64_t Offset,
584                                            uint64_t Value,
585                                            uint32_t Type,
586                                            int64_t Addend) {
587  uint8_t* LocalAddress = Section.Address + Offset;
588  switch (Type) {
589  default:
590    llvm_unreachable("Relocation type not implemented yet!");
591  break;
592  case ELF::R_PPC64_ADDR16_LO :
593    writeInt16BE(LocalAddress, applyPPClo (Value + Addend));
594    break;
595  case ELF::R_PPC64_ADDR16_HI :
596    writeInt16BE(LocalAddress, applyPPChi (Value + Addend));
597    break;
598  case ELF::R_PPC64_ADDR16_HIGHER :
599    writeInt16BE(LocalAddress, applyPPChigher (Value + Addend));
600    break;
601  case ELF::R_PPC64_ADDR16_HIGHEST :
602    writeInt16BE(LocalAddress, applyPPChighest (Value + Addend));
603    break;
604  case ELF::R_PPC64_ADDR14 : {
605    assert(((Value + Addend) & 3) == 0);
606    // Preserve the AA/LK bits in the branch instruction
607    uint8_t aalk = *(LocalAddress+3);
608    writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
609  } break;
610  case ELF::R_PPC64_ADDR32 : {
611    int32_t Result = static_cast<int32_t>(Value + Addend);
612    if (SignExtend32<32>(Result) != Result)
613      llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
614    writeInt32BE(LocalAddress, Result);
615  } break;
616  case ELF::R_PPC64_REL24 : {
617    uint64_t FinalAddress = (Section.LoadAddress + Offset);
618    int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
619    if (SignExtend32<24>(delta) != delta)
620      llvm_unreachable("Relocation R_PPC64_REL24 overflow");
621    // Generates a 'bl <address>' instruction
622    writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
623  } break;
624  case ELF::R_PPC64_REL32 : {
625    uint64_t FinalAddress = (Section.LoadAddress + Offset);
626    int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
627    if (SignExtend32<32>(delta) != delta)
628      llvm_unreachable("Relocation R_PPC64_REL32 overflow");
629    writeInt32BE(LocalAddress, delta);
630  } break;
631  case ELF::R_PPC64_REL64: {
632    uint64_t FinalAddress = (Section.LoadAddress + Offset);
633    uint64_t Delta = Value - FinalAddress + Addend;
634    writeInt64BE(LocalAddress, Delta);
635  } break;
636  case ELF::R_PPC64_ADDR64 :
637    writeInt64BE(LocalAddress, Value + Addend);
638    break;
639  case ELF::R_PPC64_TOC :
640    writeInt64BE(LocalAddress, findPPC64TOC());
641    break;
642  case ELF::R_PPC64_TOC16 : {
643    uint64_t TOCStart = findPPC64TOC();
644    Value = applyPPClo((Value + Addend) - TOCStart);
645    writeInt16BE(LocalAddress, applyPPClo(Value));
646  } break;
647  case ELF::R_PPC64_TOC16_DS : {
648    uint64_t TOCStart = findPPC64TOC();
649    Value = ((Value + Addend) - TOCStart);
650    writeInt16BE(LocalAddress, applyPPClo(Value));
651  } break;
652  }
653}
654
655void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
656                                              uint64_t Offset,
657                                              uint64_t Value,
658                                              uint32_t Type,
659                                              int64_t Addend) {
660  uint8_t *LocalAddress = Section.Address + Offset;
661  switch (Type) {
662  default:
663    llvm_unreachable("Relocation type not implemented yet!");
664    break;
665  case ELF::R_390_PC16DBL:
666  case ELF::R_390_PLT16DBL: {
667    int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
668    assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
669    writeInt16BE(LocalAddress, Delta / 2);
670    break;
671  }
672  case ELF::R_390_PC32DBL:
673  case ELF::R_390_PLT32DBL: {
674    int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
675    assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
676    writeInt32BE(LocalAddress, Delta / 2);
677    break;
678  }
679  case ELF::R_390_PC32: {
680    int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
681    assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
682    writeInt32BE(LocalAddress, Delta);
683    break;
684  }
685  case ELF::R_390_64:
686    writeInt64BE(LocalAddress, Value + Addend);
687    break;
688  }
689}
690
691void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
692				       uint64_t Value) {
693  const SectionEntry &Section = Sections[RE.SectionID];
694  return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend);
695}
696
697void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
698                                       uint64_t Offset,
699                                       uint64_t Value,
700                                       uint32_t Type,
701                                       int64_t Addend) {
702  switch (Arch) {
703  case Triple::x86_64:
704    resolveX86_64Relocation(Section, Offset, Value, Type, Addend);
705    break;
706  case Triple::x86:
707    resolveX86Relocation(Section, Offset,
708                         (uint32_t)(Value & 0xffffffffL), Type,
709                         (uint32_t)(Addend & 0xffffffffL));
710    break;
711  case Triple::aarch64:
712    resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
713    break;
714  case Triple::arm:    // Fall through.
715  case Triple::thumb:
716    resolveARMRelocation(Section, Offset,
717                         (uint32_t)(Value & 0xffffffffL), Type,
718                         (uint32_t)(Addend & 0xffffffffL));
719    break;
720  case Triple::mips:    // Fall through.
721  case Triple::mipsel:
722    resolveMIPSRelocation(Section, Offset,
723                          (uint32_t)(Value & 0xffffffffL), Type,
724                          (uint32_t)(Addend & 0xffffffffL));
725    break;
726  case Triple::ppc64:
727    resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
728    break;
729  case Triple::systemz:
730    resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
731    break;
732  default: llvm_unreachable("Unsupported CPU type!");
733  }
734}
735
736void RuntimeDyldELF::processRelocationRef(unsigned SectionID,
737                                          RelocationRef RelI,
738                                          ObjectImage &Obj,
739                                          ObjSectionToIDMap &ObjSectionToID,
740                                          const SymbolTableMap &Symbols,
741                                          StubMap &Stubs) {
742  uint64_t RelType;
743  Check(RelI.getType(RelType));
744  int64_t Addend;
745  Check(getELFRelocationAddend(RelI, Addend));
746  SymbolRef Symbol;
747  Check(RelI.getSymbol(Symbol));
748
749  // Obtain the symbol name which is referenced in the relocation
750  StringRef TargetName;
751  Symbol.getName(TargetName);
752  DEBUG(dbgs() << "\t\tRelType: " << RelType
753               << " Addend: " << Addend
754               << " TargetName: " << TargetName
755               << "\n");
756  RelocationValueRef Value;
757  // First search for the symbol in the local symbol table
758  SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data());
759  SymbolRef::Type SymType;
760  Symbol.getType(SymType);
761  if (lsi != Symbols.end()) {
762    Value.SectionID = lsi->second.first;
763    Value.Addend = lsi->second.second + Addend;
764  } else {
765    // Search for the symbol in the global symbol table
766    SymbolTableMap::const_iterator gsi =
767        GlobalSymbolTable.find(TargetName.data());
768    if (gsi != GlobalSymbolTable.end()) {
769      Value.SectionID = gsi->second.first;
770      Value.Addend = gsi->second.second + Addend;
771    } else {
772      switch (SymType) {
773        case SymbolRef::ST_Debug: {
774          // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
775          // and can be changed by another developers. Maybe best way is add
776          // a new symbol type ST_Section to SymbolRef and use it.
777          section_iterator si(Obj.end_sections());
778          Symbol.getSection(si);
779          if (si == Obj.end_sections())
780            llvm_unreachable("Symbol section not found, bad object file format!");
781          DEBUG(dbgs() << "\t\tThis is section symbol\n");
782          // Default to 'true' in case isText fails (though it never does).
783          bool isCode = true;
784          si->isText(isCode);
785          Value.SectionID = findOrEmitSection(Obj,
786                                              (*si),
787                                              isCode,
788                                              ObjSectionToID);
789          Value.Addend = Addend;
790          break;
791        }
792        case SymbolRef::ST_Unknown: {
793          Value.SymbolName = TargetName.data();
794          Value.Addend = Addend;
795          break;
796        }
797        default:
798          llvm_unreachable("Unresolved symbol type!");
799          break;
800      }
801    }
802  }
803  uint64_t Offset;
804  Check(RelI.getOffset(Offset));
805
806  DEBUG(dbgs() << "\t\tSectionID: " << SectionID
807               << " Offset: " << Offset
808               << "\n");
809  if (Arch == Triple::aarch64 &&
810      (RelType == ELF::R_AARCH64_CALL26 ||
811       RelType == ELF::R_AARCH64_JUMP26)) {
812    // This is an AArch64 branch relocation, need to use a stub function.
813    DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
814    SectionEntry &Section = Sections[SectionID];
815
816    // Look for an existing stub.
817    StubMap::const_iterator i = Stubs.find(Value);
818    if (i != Stubs.end()) {
819        resolveRelocation(Section, Offset,
820                          (uint64_t)Section.Address + i->second, RelType, 0);
821      DEBUG(dbgs() << " Stub function found\n");
822    } else {
823      // Create a new stub function.
824      DEBUG(dbgs() << " Create a new stub function\n");
825      Stubs[Value] = Section.StubOffset;
826      uint8_t *StubTargetAddr = createStubFunction(Section.Address +
827                                                   Section.StubOffset);
828
829      RelocationEntry REmovz_g3(SectionID,
830                                StubTargetAddr - Section.Address,
831                                ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
832      RelocationEntry REmovk_g2(SectionID,
833                                StubTargetAddr - Section.Address + 4,
834                                ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
835      RelocationEntry REmovk_g1(SectionID,
836                                StubTargetAddr - Section.Address + 8,
837                                ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
838      RelocationEntry REmovk_g0(SectionID,
839                                StubTargetAddr - Section.Address + 12,
840                                ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
841
842      if (Value.SymbolName) {
843        addRelocationForSymbol(REmovz_g3, Value.SymbolName);
844        addRelocationForSymbol(REmovk_g2, Value.SymbolName);
845        addRelocationForSymbol(REmovk_g1, Value.SymbolName);
846        addRelocationForSymbol(REmovk_g0, Value.SymbolName);
847      } else {
848        addRelocationForSection(REmovz_g3, Value.SectionID);
849        addRelocationForSection(REmovk_g2, Value.SectionID);
850        addRelocationForSection(REmovk_g1, Value.SectionID);
851        addRelocationForSection(REmovk_g0, Value.SectionID);
852      }
853      resolveRelocation(Section, Offset,
854                        (uint64_t)Section.Address + Section.StubOffset,
855                        RelType, 0);
856      Section.StubOffset += getMaxStubSize();
857    }
858  } else if (Arch == Triple::arm &&
859      (RelType == ELF::R_ARM_PC24 ||
860       RelType == ELF::R_ARM_CALL ||
861       RelType == ELF::R_ARM_JUMP24)) {
862    // This is an ARM branch relocation, need to use a stub function.
863    DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.");
864    SectionEntry &Section = Sections[SectionID];
865
866    // Look for an existing stub.
867    StubMap::const_iterator i = Stubs.find(Value);
868    if (i != Stubs.end()) {
869        resolveRelocation(Section, Offset,
870                          (uint64_t)Section.Address + i->second, RelType, 0);
871      DEBUG(dbgs() << " Stub function found\n");
872    } else {
873      // Create a new stub function.
874      DEBUG(dbgs() << " Create a new stub function\n");
875      Stubs[Value] = Section.StubOffset;
876      uint8_t *StubTargetAddr = createStubFunction(Section.Address +
877                                                   Section.StubOffset);
878      RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
879                         ELF::R_ARM_ABS32, Value.Addend);
880      if (Value.SymbolName)
881        addRelocationForSymbol(RE, Value.SymbolName);
882      else
883        addRelocationForSection(RE, Value.SectionID);
884
885      resolveRelocation(Section, Offset,
886                        (uint64_t)Section.Address + Section.StubOffset,
887                        RelType, 0);
888      Section.StubOffset += getMaxStubSize();
889    }
890  } else if ((Arch == Triple::mipsel || Arch == Triple::mips) &&
891             RelType == ELF::R_MIPS_26) {
892    // This is an Mips branch relocation, need to use a stub function.
893    DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
894    SectionEntry &Section = Sections[SectionID];
895    uint8_t *Target = Section.Address + Offset;
896    uint32_t *TargetAddress = (uint32_t *)Target;
897
898    // Extract the addend from the instruction.
899    uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2;
900
901    Value.Addend += Addend;
902
903    //  Look up for existing stub.
904    StubMap::const_iterator i = Stubs.find(Value);
905    if (i != Stubs.end()) {
906      resolveRelocation(Section, Offset,
907                        (uint64_t)Section.Address + i->second, RelType, 0);
908      DEBUG(dbgs() << " Stub function found\n");
909    } else {
910      // Create a new stub function.
911      DEBUG(dbgs() << " Create a new stub function\n");
912      Stubs[Value] = Section.StubOffset;
913      uint8_t *StubTargetAddr = createStubFunction(Section.Address +
914                                                   Section.StubOffset);
915
916      // Creating Hi and Lo relocations for the filled stub instructions.
917      RelocationEntry REHi(SectionID,
918                           StubTargetAddr - Section.Address,
919                           ELF::R_MIPS_HI16, Value.Addend);
920      RelocationEntry RELo(SectionID,
921                           StubTargetAddr - Section.Address + 4,
922                           ELF::R_MIPS_LO16, Value.Addend);
923
924      if (Value.SymbolName) {
925        addRelocationForSymbol(REHi, Value.SymbolName);
926        addRelocationForSymbol(RELo, Value.SymbolName);
927      } else {
928        addRelocationForSection(REHi, Value.SectionID);
929        addRelocationForSection(RELo, Value.SectionID);
930      }
931
932      resolveRelocation(Section, Offset,
933                        (uint64_t)Section.Address + Section.StubOffset,
934                        RelType, 0);
935      Section.StubOffset += getMaxStubSize();
936    }
937  } else if (Arch == Triple::ppc64) {
938    if (RelType == ELF::R_PPC64_REL24) {
939      // A PPC branch relocation will need a stub function if the target is
940      // an external symbol (Symbol::ST_Unknown) or if the target address
941      // is not within the signed 24-bits branch address.
942      SectionEntry &Section = Sections[SectionID];
943      uint8_t *Target = Section.Address + Offset;
944      bool RangeOverflow = false;
945      if (SymType != SymbolRef::ST_Unknown) {
946        // A function call may points to the .opd entry, so the final symbol value
947        // in calculated based in the relocation values in .opd section.
948        findOPDEntrySection(Obj, ObjSectionToID, Value);
949        uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend;
950        int32_t delta = static_cast<int32_t>(Target - RelocTarget);
951        // If it is within 24-bits branch range, just set the branch target
952        if (SignExtend32<24>(delta) == delta) {
953          RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
954          if (Value.SymbolName)
955            addRelocationForSymbol(RE, Value.SymbolName);
956          else
957            addRelocationForSection(RE, Value.SectionID);
958        } else {
959          RangeOverflow = true;
960        }
961      }
962      if (SymType == SymbolRef::ST_Unknown || RangeOverflow == true) {
963        // It is an external symbol (SymbolRef::ST_Unknown) or within a range
964        // larger than 24-bits.
965        StubMap::const_iterator i = Stubs.find(Value);
966        if (i != Stubs.end()) {
967          // Symbol function stub already created, just relocate to it
968          resolveRelocation(Section, Offset,
969                            (uint64_t)Section.Address + i->second, RelType, 0);
970          DEBUG(dbgs() << " Stub function found\n");
971        } else {
972          // Create a new stub function.
973          DEBUG(dbgs() << " Create a new stub function\n");
974          Stubs[Value] = Section.StubOffset;
975          uint8_t *StubTargetAddr = createStubFunction(Section.Address +
976                                                       Section.StubOffset);
977          RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
978                             ELF::R_PPC64_ADDR64, Value.Addend);
979
980          // Generates the 64-bits address loads as exemplified in section
981          // 4.5.1 in PPC64 ELF ABI.
982          RelocationEntry REhst(SectionID,
983                                StubTargetAddr - Section.Address + 2,
984                                ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
985          RelocationEntry REhr(SectionID,
986                               StubTargetAddr - Section.Address + 6,
987                               ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
988          RelocationEntry REh(SectionID,
989                              StubTargetAddr - Section.Address + 14,
990                              ELF::R_PPC64_ADDR16_HI, Value.Addend);
991          RelocationEntry REl(SectionID,
992                              StubTargetAddr - Section.Address + 18,
993                              ELF::R_PPC64_ADDR16_LO, Value.Addend);
994
995          if (Value.SymbolName) {
996            addRelocationForSymbol(REhst, Value.SymbolName);
997            addRelocationForSymbol(REhr,  Value.SymbolName);
998            addRelocationForSymbol(REh,   Value.SymbolName);
999            addRelocationForSymbol(REl,   Value.SymbolName);
1000          } else {
1001            addRelocationForSection(REhst, Value.SectionID);
1002            addRelocationForSection(REhr,  Value.SectionID);
1003            addRelocationForSection(REh,   Value.SectionID);
1004            addRelocationForSection(REl,   Value.SectionID);
1005          }
1006
1007          resolveRelocation(Section, Offset,
1008                            (uint64_t)Section.Address + Section.StubOffset,
1009                            RelType, 0);
1010          if (SymType == SymbolRef::ST_Unknown)
1011            // Restore the TOC for external calls
1012            writeInt32BE(Target+4, 0xE8410028); // ld r2,40(r1)
1013          Section.StubOffset += getMaxStubSize();
1014        }
1015      }
1016    } else {
1017      RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1018      // Extra check to avoid relocation againt empty symbols (usually
1019      // the R_PPC64_TOC).
1020      if (Value.SymbolName && !TargetName.empty())
1021        addRelocationForSymbol(RE, Value.SymbolName);
1022      else
1023        addRelocationForSection(RE, Value.SectionID);
1024    }
1025  } else if (Arch == Triple::systemz &&
1026             (RelType == ELF::R_390_PLT32DBL ||
1027              RelType == ELF::R_390_GOTENT)) {
1028    // Create function stubs for both PLT and GOT references, regardless of
1029    // whether the GOT reference is to data or code.  The stub contains the
1030    // full address of the symbol, as needed by GOT references, and the
1031    // executable part only adds an overhead of 8 bytes.
1032    //
1033    // We could try to conserve space by allocating the code and data
1034    // parts of the stub separately.  However, as things stand, we allocate
1035    // a stub for every relocation, so using a GOT in JIT code should be
1036    // no less space efficient than using an explicit constant pool.
1037    DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1038    SectionEntry &Section = Sections[SectionID];
1039
1040    // Look for an existing stub.
1041    StubMap::const_iterator i = Stubs.find(Value);
1042    uintptr_t StubAddress;
1043    if (i != Stubs.end()) {
1044      StubAddress = uintptr_t(Section.Address) + i->second;
1045      DEBUG(dbgs() << " Stub function found\n");
1046    } else {
1047      // Create a new stub function.
1048      DEBUG(dbgs() << " Create a new stub function\n");
1049
1050      uintptr_t BaseAddress = uintptr_t(Section.Address);
1051      uintptr_t StubAlignment = getStubAlignment();
1052      StubAddress = (BaseAddress + Section.StubOffset +
1053                     StubAlignment - 1) & -StubAlignment;
1054      unsigned StubOffset = StubAddress - BaseAddress;
1055
1056      Stubs[Value] = StubOffset;
1057      createStubFunction((uint8_t *)StubAddress);
1058      RelocationEntry RE(SectionID, StubOffset + 8,
1059                         ELF::R_390_64, Value.Addend - Addend);
1060      if (Value.SymbolName)
1061        addRelocationForSymbol(RE, Value.SymbolName);
1062      else
1063        addRelocationForSection(RE, Value.SectionID);
1064      Section.StubOffset = StubOffset + getMaxStubSize();
1065    }
1066
1067    if (RelType == ELF::R_390_GOTENT)
1068      resolveRelocation(Section, Offset, StubAddress + 8,
1069                        ELF::R_390_PC32DBL, Addend);
1070    else
1071      resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1072  } else {
1073    RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1074    if (Value.SymbolName)
1075      addRelocationForSymbol(RE, Value.SymbolName);
1076    else
1077      addRelocationForSection(RE, Value.SectionID);
1078  }
1079}
1080
1081bool RuntimeDyldELF::isCompatibleFormat(const ObjectBuffer *Buffer) const {
1082  if (Buffer->getBufferSize() < strlen(ELF::ElfMagic))
1083    return false;
1084  return (memcmp(Buffer->getBufferStart(), ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0;
1085}
1086} // namespace llvm
1087