LLVM  4.0.0
RuntimeDyldMachO.cpp
Go to the documentation of this file.
1 //===-- RuntimeDyldMachO.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-=//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Implementation of the MC-JIT runtime dynamic linker.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "RuntimeDyldMachO.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/StringRef.h"
21 
22 using namespace llvm;
23 using namespace llvm::object;
24 
25 #define DEBUG_TYPE "dyld"
26 
27 namespace {
28 
29 class LoadedMachOObjectInfo final
30  : public RuntimeDyld::LoadedObjectInfoHelper<LoadedMachOObjectInfo> {
31 public:
32  LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
33  ObjSectionToIDMap ObjSecToIDMap)
34  : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
35 
37  getObjectForDebug(const ObjectFile &Obj) const override {
38  return OwningBinary<ObjectFile>();
39  }
40 };
41 
42 }
43 
44 namespace llvm {
45 
47  unsigned NumBytes = 1 << RE.Size;
48  uint8_t *Src = Sections[RE.SectionID].getAddress() + RE.Offset;
49 
50  return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
51 }
52 
55  unsigned SectionID, relocation_iterator RelI,
56  const ObjectFile &BaseObjT,
57  RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID) {
58  const MachOObjectFile &Obj =
59  static_cast<const MachOObjectFile&>(BaseObjT);
61  Obj.getRelocation(RelI->getRawDataRefImpl());
62 
63  SectionEntry &Section = Sections[SectionID];
64  uint32_t RelocType = Obj.getAnyRelocationType(RE);
65  bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
66  unsigned Size = Obj.getAnyRelocationLength(RE);
67  uint64_t Offset = RelI->getOffset();
68  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
69  unsigned NumBytes = 1 << Size;
70  int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
71 
72  unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
73  section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
74  assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
75  uint64_t SectionBaseAddr = TargetSI->getAddress();
76  SectionRef TargetSection = *TargetSI;
77  bool IsCode = TargetSection.isText();
78  uint32_t TargetSectionID = ~0U;
79  if (auto TargetSectionIDOrErr =
80  findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID))
81  TargetSectionID = *TargetSectionIDOrErr;
82  else
83  return TargetSectionIDOrErr.takeError();
84 
85  Addend -= SectionBaseAddr;
86  RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
87 
88  addRelocationForSection(R, TargetSectionID);
89 
90  return ++RelI;
91 }
92 
93 
96  const ObjectFile &BaseTObj, const relocation_iterator &RI,
97  const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
98 
99  const MachOObjectFile &Obj =
100  static_cast<const MachOObjectFile &>(BaseTObj);
102  Obj.getRelocation(RI->getRawDataRefImpl());
104 
105  bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
106  if (IsExternal) {
107  symbol_iterator Symbol = RI->getSymbol();
108  StringRef TargetName;
109  if (auto TargetNameOrErr = Symbol->getName())
110  TargetName = *TargetNameOrErr;
111  else
112  return TargetNameOrErr.takeError();
114  GlobalSymbolTable.find(TargetName.data());
115  if (SI != GlobalSymbolTable.end()) {
116  const auto &SymInfo = SI->second;
117  Value.SectionID = SymInfo.getSectionID();
118  Value.Offset = SymInfo.getOffset() + RE.Addend;
119  } else {
120  Value.SymbolName = TargetName.data();
121  Value.Offset = RE.Addend;
122  }
123  } else {
124  SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
125  bool IsCode = Sec.isText();
126  if (auto SectionIDOrErr = findOrEmitSection(Obj, Sec, IsCode,
127  ObjSectionToID))
128  Value.SectionID = *SectionIDOrErr;
129  else
130  return SectionIDOrErr.takeError();
131  uint64_t Addr = Sec.getAddress();
132  Value.Offset = RE.Addend - Addr;
133  }
134 
135  return Value;
136 }
137 
139  const relocation_iterator &RI,
140  unsigned OffsetToNextPC) {
141  auto &O = *cast<MachOObjectFile>(RI->getObject());
142  section_iterator SecI = O.getRelocationRelocatedSection(RI);
143  Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
144 }
145 
147  uint64_t Value) const {
148  const SectionEntry &Section = Sections[RE.SectionID];
149  uint8_t *LocalAddress = Section.getAddress() + RE.Offset;
150  uint64_t FinalAddress = Section.getLoadAddress() + RE.Offset;
151 
152  dbgs() << "resolveRelocation Section: " << RE.SectionID
153  << " LocalAddress: " << format("%p", LocalAddress)
154  << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
155  << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
156  << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
157  << " Size: " << (1 << RE.Size) << "\n";
158 }
159 
162  uint64_t Addr) {
164  section_iterator SE = Obj.section_end();
165 
166  for (; SI != SE; ++SI) {
167  uint64_t SAddr = SI->getAddress();
168  uint64_t SSize = SI->getSize();
169  if ((Addr >= SAddr) && (Addr < SAddr + SSize))
170  return SI;
171  }
172 
173  return SE;
174 }
175 
176 
177 // Populate __pointers section.
179  const MachOObjectFile &Obj,
180  const SectionRef &PTSection,
181  unsigned PTSectionID) {
182  assert(!Obj.is64Bit() &&
183  "Pointer table section not supported in 64-bit MachO.");
184 
186  MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
187  uint32_t PTSectionSize = Sec32.size;
188  unsigned FirstIndirectSymbol = Sec32.reserved1;
189  const unsigned PTEntrySize = 4;
190  unsigned NumPTEntries = PTSectionSize / PTEntrySize;
191  unsigned PTEntryOffset = 0;
192 
193  assert((PTSectionSize % PTEntrySize) == 0 &&
194  "Pointers section does not contain a whole number of stubs?");
195 
196  DEBUG(dbgs() << "Populating pointer table section "
197  << Sections[PTSectionID].getName() << ", Section ID "
198  << PTSectionID << ", " << NumPTEntries << " entries, "
199  << PTEntrySize << " bytes each:\n");
200 
201  for (unsigned i = 0; i < NumPTEntries; ++i) {
202  unsigned SymbolIndex =
203  Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
204  symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
205  StringRef IndirectSymbolName;
206  if (auto IndirectSymbolNameOrErr = SI->getName())
207  IndirectSymbolName = *IndirectSymbolNameOrErr;
208  else
209  return IndirectSymbolNameOrErr.takeError();
210  DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
211  << ", PT offset: " << PTEntryOffset << "\n");
212  RelocationEntry RE(PTSectionID, PTEntryOffset,
213  MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
214  addRelocationForSymbol(RE, IndirectSymbolName);
215  PTEntryOffset += PTEntrySize;
216  }
217  return Error::success();
218 }
219 
221  return Obj.isMachO();
222 }
223 
224 template <typename Impl>
225 Error
227  ObjSectionToIDMap &SectionMap) {
228  unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
229  unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
230  unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
231 
232  for (const auto &Section : Obj.sections()) {
233  StringRef Name;
234  Section.getName(Name);
235 
236  // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
237  // if they're present. Otherwise call down to the impl to handle other
238  // sections that have already been emitted.
239  if (Name == "__text") {
240  if (auto TextSIDOrErr = findOrEmitSection(Obj, Section, true, SectionMap))
241  TextSID = *TextSIDOrErr;
242  else
243  return TextSIDOrErr.takeError();
244  } else if (Name == "__eh_frame") {
245  if (auto EHFrameSIDOrErr = findOrEmitSection(Obj, Section, false,
246  SectionMap))
247  EHFrameSID = *EHFrameSIDOrErr;
248  else
249  return EHFrameSIDOrErr.takeError();
250  } else if (Name == "__gcc_except_tab") {
251  if (auto ExceptTabSIDOrErr = findOrEmitSection(Obj, Section, true,
252  SectionMap))
253  ExceptTabSID = *ExceptTabSIDOrErr;
254  else
255  return ExceptTabSIDOrErr.takeError();
256  } else {
257  auto I = SectionMap.find(Section);
258  if (I != SectionMap.end())
259  if (auto Err = impl().finalizeSection(Obj, I->second, Section))
260  return Err;
261  }
262  }
263  UnregisteredEHFrameSections.push_back(
264  EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
265 
266  return Error::success();
267 }
268 
269 template <typename Impl>
270 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(uint8_t *P,
271  int64_t DeltaForText,
272  int64_t DeltaForEH) {
273  typedef typename Impl::TargetPtrT TargetPtrT;
274 
275  DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
276  << ", Delta for EH: " << DeltaForEH << "\n");
277  uint32_t Length = readBytesUnaligned(P, 4);
278  P += 4;
279  uint8_t *Ret = P + Length;
280  uint32_t Offset = readBytesUnaligned(P, 4);
281  if (Offset == 0) // is a CIE
282  return Ret;
283 
284  P += 4;
285  TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
286  TargetPtrT NewLocation = FDELocation - DeltaForText;
287  writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
288 
289  P += sizeof(TargetPtrT);
290 
291  // Skip the FDE address range
292  P += sizeof(TargetPtrT);
293 
294  uint8_t Augmentationsize = *P;
295  P += 1;
296  if (Augmentationsize != 0) {
297  TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
298  TargetPtrT NewLSDA = LSDA - DeltaForEH;
299  writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
300  }
301 
302  return Ret;
303 }
304 
306  int64_t ObjDistance = static_cast<int64_t>(A->getObjAddress()) -
307  static_cast<int64_t>(B->getObjAddress());
308  int64_t MemDistance = A->getLoadAddress() - B->getLoadAddress();
309  return ObjDistance - MemDistance;
310 }
311 
312 template <typename Impl>
314 
315  for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
316  EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
317  if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
318  SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
319  continue;
320  SectionEntry *Text = &Sections[SectionInfo.TextSID];
321  SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
322  SectionEntry *ExceptTab = nullptr;
323  if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
324  ExceptTab = &Sections[SectionInfo.ExceptTabSID];
325 
326  int64_t DeltaForText = computeDelta(Text, EHFrame);
327  int64_t DeltaForEH = 0;
328  if (ExceptTab)
329  DeltaForEH = computeDelta(ExceptTab, EHFrame);
330 
331  uint8_t *P = EHFrame->getAddress();
332  uint8_t *End = P + EHFrame->getSize();
333  while (P != End) {
334  P = processFDE(P, DeltaForText, DeltaForEH);
335  }
336 
337  MemMgr.registerEHFrames(EHFrame->getAddress(), EHFrame->getLoadAddress(),
338  EHFrame->getSize());
339  }
340  UnregisteredEHFrameSections.clear();
341 }
342 
343 std::unique_ptr<RuntimeDyldMachO>
346  JITSymbolResolver &Resolver) {
347  switch (Arch) {
348  default:
349  llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
350  break;
351  case Triple::arm:
352  return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
353  case Triple::aarch64:
354  return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
355  case Triple::x86:
356  return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
357  case Triple::x86_64:
358  return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
359  }
360 }
361 
362 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
364  if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
365  return llvm::make_unique<LoadedMachOObjectInfo>(*this,
366  *ObjSectionToIDOrErr);
367  else {
368  HasError = true;
369  raw_string_ostream ErrStream(ErrorStr);
370  logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, "");
371  return nullptr;
372  }
373 }
374 
375 } // end namespace llvm
RelocationEntry - used to represent relocations internally in the dynamic linker. ...
bool getPlainRelocationExternal(const MachO::any_relocation_info &RE) const
size_t getSize() const
Error finalizeLoad(const ObjectFile &Obj, ObjSectionToIDMap &SectionMap) override
Expected< StringRef > getName() const
Definition: ObjectFile.h:316
size_t i
void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner)
Log all errors (if any) in E to OS.
unsigned getAnyRelocationType(const MachO::any_relocation_info &RE) const
uintptr_t getObjAddress() const
uint8_t * getAddress() const
This class is the base class for all object file types.
Definition: ObjectFile.h:178
DataRefImpl getRawDataRefImpl() const
Definition: ObjectFile.h:428
uint32_t getIndirectSymbolTableEntry(const MachO::dysymtab_command &DLC, unsigned Index) const
bool isCompatibleFile(const object::ObjectFile &Obj) const override
bool IsPCRel
True if this is a PCRel relocation (MachO specific).
unsigned SectionID
SectionID - the section this relocation points to.
static StringRef getName(Value *V)
int64_t memcpyAddend(const RelocationEntry &RE) const
This convenience method uses memcpy to extract a contiguous addend (the addend size and offset are ta...
Tagged union holding either a T or a Error.
uint32_t getScatteredRelocationValue(const MachO::any_relocation_info &RE) const
static std::unique_ptr< RuntimeDyldMachO > create(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver)
Create a RuntimeDyldMachO instance for the given target architecture.
place backedge safepoints impl
static GCRegistry::Add< OcamlGC > B("ocaml","ocaml 3.10-compatible GC")
format_object< Ts...> format(const char *Fmt, const Ts &...Vals)
These are helper functions used to produce formatted output.
Definition: Format.h:124
void dumpRelocationToResolve(const RelocationEntry &RE, uint64_t Value) const
Dump information about the relocation entry (RE) and resolved value.
RuntimeDyldMachOTarget - Templated base class for generic MachO linker algorithms and data structures...
#define P(N)
Expected< RelocationValueRef > getRelocationValueRef(const ObjectFile &BaseTObj, const relocation_iterator &RI, const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID)
Construct a RelocationValueRef representing the relocation target.
uint8_t * getAddressWithOffset(unsigned OffsetBytes) const
Return the address of this section with an offset.
MachO::any_relocation_info getRelocation(DataRefImpl Rel) const
MachO::section getSection(DataRefImpl DRI) const
static int64_t computeDelta(SectionEntry *A, SectionEntry *B)
bool isText() const
Definition: ObjectFile.h:396
unsigned getAnyRelocationPCRel(const MachO::any_relocation_info &RE) const
uint32_t Offset
Symbol resolution.
Definition: JITSymbol.h:165
static const unsigned End
Expected< relocation_iterator > processScatteredVANILLA(unsigned SectionID, relocation_iterator RelI, const ObjectFile &BaseObjT, RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID)
Process a scattered vanilla relocation.
section_iterator_range sections() const
Definition: ObjectFile.h:257
uint64_t getAddress() const
Definition: ObjectFile.h:376
static section_iterator getSectionByAddress(const MachOObjectFile &Obj, uint64_t Addr)
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
static ErrorSuccess success()
Create a success value.
unsigned getAnyRelocationLength(const MachO::any_relocation_info &RE) const
bool isMachO() const
Definition: Binary.h:112
int64_t Addend
Addend - the relocation addend encoded in the instruction itself.
uint32_t RelType
RelType - relocation type.
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
SectionRef getAnyRelocationSection(const MachO::any_relocation_info &RE) const
#define RTDYLD_INVALID_SECTION_ID
uint64_t Offset
Offset - offset into the section.
std::map< SectionRef, unsigned > ObjSectionToIDMap
#define I(x, y, z)
Definition: MD5.cpp:54
basic_symbol_iterator getSymbolByIndex(unsigned Index) const
section_iterator section_begin() const override
std::unique_ptr< RuntimeDyld::LoadedObjectInfo > loadObject(const object::ObjectFile &O) override
MachO::dysymtab_command getDysymtabLoadCommand() const
uint64_t getLoadAddress() const
SectionEntry - represents a section emitted into memory by the dynamic linker.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
A raw_ostream that writes to an std::string.
Definition: raw_ostream.h:463
LLVM Value Representation.
Definition: Value.h:71
Lightweight error class with error context and mandatory checking.
unsigned Size
The size of this relocation (MachO specific).
section_iterator section_end() const override
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:125
#define DEBUG(X)
Definition: Debug.h:100
Error populateIndirectSymbolPointersSection(const MachOObjectFile &Obj, const SectionRef &PTSection, unsigned PTSectionID)
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:47
void makeValueAddendPCRel(RelocationValueRef &Value, const relocation_iterator &RI, unsigned OffsetToNextPC)
Make the RelocationValueRef addend PC-relative.
static GCRegistry::Add< ErlangGC > A("erlang","erlang-compatible garbage collector")
This is a value type class that represents a single section in the list of sections in the object fil...
Definition: ObjectFile.h:70