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RuntimeDyldMachO.cpp
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1 //===-- RuntimeDyldMachO.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-=//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Implementation of the MC-JIT runtime dynamic linker.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "RuntimeDyldMachO.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/ADT/StringRef.h"
20 
21 using namespace llvm;
22 using namespace llvm::object;
23 
24 #define DEBUG_TYPE "dyld"
25 
26 namespace {
27 
28 class LoadedMachOObjectInfo final
29  : public LoadedObjectInfoHelper<LoadedMachOObjectInfo,
30  RuntimeDyld::LoadedObjectInfo> {
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,
58  bool TargetIsLocalThumbFunc) {
59  const MachOObjectFile &Obj =
60  static_cast<const MachOObjectFile&>(BaseObjT);
62  Obj.getRelocation(RelI->getRawDataRefImpl());
63 
64  SectionEntry &Section = Sections[SectionID];
65  uint32_t RelocType = Obj.getAnyRelocationType(RE);
66  bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
67  unsigned Size = Obj.getAnyRelocationLength(RE);
68  uint64_t Offset = RelI->getOffset();
69  uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
70  unsigned NumBytes = 1 << Size;
71  int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
72 
73  unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
74  section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
75  assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
76  uint64_t SectionBaseAddr = TargetSI->getAddress();
77  SectionRef TargetSection = *TargetSI;
78  bool IsCode = TargetSection.isText();
79  uint32_t TargetSectionID = ~0U;
80  if (auto TargetSectionIDOrErr =
81  findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID))
82  TargetSectionID = *TargetSectionIDOrErr;
83  else
84  return TargetSectionIDOrErr.takeError();
85 
86  Addend -= SectionBaseAddr;
87  RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
88  R.IsTargetThumbFunc = TargetIsLocalThumbFunc;
89 
90  addRelocationForSection(R, TargetSectionID);
91 
92  return ++RelI;
93 }
94 
95 
98  const ObjectFile &BaseTObj, const relocation_iterator &RI,
99  const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
100 
101  const MachOObjectFile &Obj =
102  static_cast<const MachOObjectFile &>(BaseTObj);
104  Obj.getRelocation(RI->getRawDataRefImpl());
106 
107  bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
108  if (IsExternal) {
109  symbol_iterator Symbol = RI->getSymbol();
110  StringRef TargetName;
111  if (auto TargetNameOrErr = Symbol->getName())
112  TargetName = *TargetNameOrErr;
113  else
114  return TargetNameOrErr.takeError();
116  GlobalSymbolTable.find(TargetName.data());
117  if (SI != GlobalSymbolTable.end()) {
118  const auto &SymInfo = SI->second;
119  Value.SectionID = SymInfo.getSectionID();
120  Value.Offset = SymInfo.getOffset() + RE.Addend;
121  } else {
122  Value.SymbolName = TargetName.data();
123  Value.Offset = RE.Addend;
124  }
125  } else {
126  SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
127  bool IsCode = Sec.isText();
128  if (auto SectionIDOrErr = findOrEmitSection(Obj, Sec, IsCode,
129  ObjSectionToID))
130  Value.SectionID = *SectionIDOrErr;
131  else
132  return SectionIDOrErr.takeError();
133  uint64_t Addr = Sec.getAddress();
134  Value.Offset = RE.Addend - Addr;
135  }
136 
137  return Value;
138 }
139 
141  const relocation_iterator &RI,
142  unsigned OffsetToNextPC) {
143  auto &O = *cast<MachOObjectFile>(RI->getObject());
144  section_iterator SecI = O.getRelocationRelocatedSection(RI);
145  Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
146 }
147 
149  uint64_t Value) const {
150  const SectionEntry &Section = Sections[RE.SectionID];
151  uint8_t *LocalAddress = Section.getAddress() + RE.Offset;
152  uint64_t FinalAddress = Section.getLoadAddress() + RE.Offset;
153 
154  dbgs() << "resolveRelocation Section: " << RE.SectionID
155  << " LocalAddress: " << format("%p", LocalAddress)
156  << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
157  << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
158  << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
159  << " Size: " << (1 << RE.Size) << "\n";
160 }
161 
164  uint64_t Addr) {
166  section_iterator SE = Obj.section_end();
167 
168  for (; SI != SE; ++SI) {
169  uint64_t SAddr = SI->getAddress();
170  uint64_t SSize = SI->getSize();
171  if ((Addr >= SAddr) && (Addr < SAddr + SSize))
172  return SI;
173  }
174 
175  return SE;
176 }
177 
178 
179 // Populate __pointers section.
181  const MachOObjectFile &Obj,
182  const SectionRef &PTSection,
183  unsigned PTSectionID) {
184  assert(!Obj.is64Bit() &&
185  "Pointer table section not supported in 64-bit MachO.");
186 
188  MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
189  uint32_t PTSectionSize = Sec32.size;
190  unsigned FirstIndirectSymbol = Sec32.reserved1;
191  const unsigned PTEntrySize = 4;
192  unsigned NumPTEntries = PTSectionSize / PTEntrySize;
193  unsigned PTEntryOffset = 0;
194 
195  assert((PTSectionSize % PTEntrySize) == 0 &&
196  "Pointers section does not contain a whole number of stubs?");
197 
198  LLVM_DEBUG(dbgs() << "Populating pointer table section "
199  << Sections[PTSectionID].getName() << ", Section ID "
200  << PTSectionID << ", " << NumPTEntries << " entries, "
201  << PTEntrySize << " bytes each:\n");
202 
203  for (unsigned i = 0; i < NumPTEntries; ++i) {
204  unsigned SymbolIndex =
205  Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
206  symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
207  StringRef IndirectSymbolName;
208  if (auto IndirectSymbolNameOrErr = SI->getName())
209  IndirectSymbolName = *IndirectSymbolNameOrErr;
210  else
211  return IndirectSymbolNameOrErr.takeError();
212  LLVM_DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
213  << ", PT offset: " << PTEntryOffset << "\n");
214  RelocationEntry RE(PTSectionID, PTEntryOffset,
215  MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
216  addRelocationForSymbol(RE, IndirectSymbolName);
217  PTEntryOffset += PTEntrySize;
218  }
219  return Error::success();
220 }
221 
223  return Obj.isMachO();
224 }
225 
226 template <typename Impl>
227 Error
229  ObjSectionToIDMap &SectionMap) {
230  unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
231  unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
232  unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
233 
234  for (const auto &Section : Obj.sections()) {
235  StringRef Name;
236  if (Expected<StringRef> NameOrErr = Section.getName())
237  Name = *NameOrErr;
238  else
239  consumeError(NameOrErr.takeError());
240 
241  // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
242  // if they're present. Otherwise call down to the impl to handle other
243  // sections that have already been emitted.
244  if (Name == "__text") {
245  if (auto TextSIDOrErr = findOrEmitSection(Obj, Section, true, SectionMap))
246  TextSID = *TextSIDOrErr;
247  else
248  return TextSIDOrErr.takeError();
249  } else if (Name == "__eh_frame") {
250  if (auto EHFrameSIDOrErr = findOrEmitSection(Obj, Section, false,
251  SectionMap))
252  EHFrameSID = *EHFrameSIDOrErr;
253  else
254  return EHFrameSIDOrErr.takeError();
255  } else if (Name == "__gcc_except_tab") {
256  if (auto ExceptTabSIDOrErr = findOrEmitSection(Obj, Section, true,
257  SectionMap))
258  ExceptTabSID = *ExceptTabSIDOrErr;
259  else
260  return ExceptTabSIDOrErr.takeError();
261  } else {
262  auto I = SectionMap.find(Section);
263  if (I != SectionMap.end())
264  if (auto Err = impl().finalizeSection(Obj, I->second, Section))
265  return Err;
266  }
267  }
268  UnregisteredEHFrameSections.push_back(
269  EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
270 
271  return Error::success();
272 }
273 
274 template <typename Impl>
275 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(uint8_t *P,
276  int64_t DeltaForText,
277  int64_t DeltaForEH) {
278  typedef typename Impl::TargetPtrT TargetPtrT;
279 
280  LLVM_DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
281  << ", Delta for EH: " << DeltaForEH << "\n");
282  uint32_t Length = readBytesUnaligned(P, 4);
283  P += 4;
284  uint8_t *Ret = P + Length;
285  uint32_t Offset = readBytesUnaligned(P, 4);
286  if (Offset == 0) // is a CIE
287  return Ret;
288 
289  P += 4;
290  TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
291  TargetPtrT NewLocation = FDELocation - DeltaForText;
292  writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
293 
294  P += sizeof(TargetPtrT);
295 
296  // Skip the FDE address range
297  P += sizeof(TargetPtrT);
298 
299  uint8_t Augmentationsize = *P;
300  P += 1;
301  if (Augmentationsize != 0) {
302  TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
303  TargetPtrT NewLSDA = LSDA - DeltaForEH;
304  writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
305  }
306 
307  return Ret;
308 }
309 
310 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
311  int64_t ObjDistance = static_cast<int64_t>(A->getObjAddress()) -
312  static_cast<int64_t>(B->getObjAddress());
313  int64_t MemDistance = A->getLoadAddress() - B->getLoadAddress();
314  return ObjDistance - MemDistance;
315 }
316 
317 template <typename Impl>
319 
320  for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
321  EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
322  if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
323  SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
324  continue;
325  SectionEntry *Text = &Sections[SectionInfo.TextSID];
326  SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
327  SectionEntry *ExceptTab = nullptr;
328  if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
329  ExceptTab = &Sections[SectionInfo.ExceptTabSID];
330 
331  int64_t DeltaForText = computeDelta(Text, EHFrame);
332  int64_t DeltaForEH = 0;
333  if (ExceptTab)
334  DeltaForEH = computeDelta(ExceptTab, EHFrame);
335 
336  uint8_t *P = EHFrame->getAddress();
337  uint8_t *End = P + EHFrame->getSize();
338  while (P != End) {
339  P = processFDE(P, DeltaForText, DeltaForEH);
340  }
341 
342  MemMgr.registerEHFrames(EHFrame->getAddress(), EHFrame->getLoadAddress(),
343  EHFrame->getSize());
344  }
345  UnregisteredEHFrameSections.clear();
346 }
347 
348 std::unique_ptr<RuntimeDyldMachO>
352  switch (Arch) {
353  default:
354  llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
355  break;
356  case Triple::arm:
357  return std::make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
358  case Triple::aarch64:
359  return std::make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
360  case Triple::aarch64_32:
361  return std::make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
362  case Triple::x86:
363  return std::make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
364  case Triple::x86_64:
365  return std::make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
366  }
367 }
368 
369 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
371  if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
372  return std::make_unique<LoadedMachOObjectInfo>(*this,
373  *ObjSectionToIDOrErr);
374  else {
375  HasError = true;
376  raw_string_ostream ErrStream(ErrorStr);
377  logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream);
378  return nullptr;
379  }
380 }
381 
382 } // end namespace llvm
RelocationEntry - used to represent relocations internally in the dynamic linker. ...
Error finalizeLoad(const ObjectFile &Obj, ObjSectionToIDMap &SectionMap) override
This class represents lattice values for constants.
Definition: AllocatorList.h:23
Expected< StringRef > getName() const
Definition: ObjectFile.h:375
unsigned getAnyRelocationPCRel(const MachO::any_relocation_info &RE) const
amdgpu Simplify well known AMD library false FunctionCallee Value const Twine & Name
format_object< Ts... > format(const char *Fmt, const Ts &... Vals)
These are helper functions used to produce formatted output.
Definition: Format.h:124
uint32_t reserved1
Definition: MachO.h:565
bool getPlainRelocationExternal(const MachO::any_relocation_info &RE) const
Expected< SectionRef > getSection(unsigned SectionIndex) const
void dumpRelocationToResolve(const RelocationEntry &RE, uint64_t Value) const
Dump information about the relocation entry (RE) and resolved value.
This class is the base class for all object file types.
Definition: ObjectFile.h:221
uint32_t size
Definition: MachO.h:559
uint8_t * getAddress() 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.
uint64_t getAddress() const
Definition: ObjectFile.h:436
static StringRef getName(Value *V)
bool isText() const
Whether this section contains instructions.
Definition: ObjectFile.h:464
Tagged union holding either a T or a Error.
Definition: yaml2obj.h:21
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
int64_t memcpyAddend(const RelocationEntry &RE) const
This convenience method uses memcpy to extract a contiguous addend (the addend size and offset are ta...
SectionRef getAnyRelocationSection(const MachO::any_relocation_info &RE) const
symbol_iterator getSymbolByIndex(unsigned Index) const
section_iterator_range sections() const
Definition: ObjectFile.h:310
unsigned getAnyRelocationType(const MachO::any_relocation_info &RE) const
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.
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
static int64_t computeDelta(SectionEntry *A, SectionEntry *B)
MachO::any_relocation_info getRelocation(DataRefImpl Rel) const
Interface for looking up the initializer for a variable name, used by Init::resolveReferences.
Definition: Record.h:1864
Symbol resolution interface.
Definition: JITSymbol.h:325
constexpr double e
Definition: MathExtras.h:57
uintptr_t getObjAddress() const
DataRefImpl getRawDataRefImpl() const
Definition: ObjectFile.h:508
void consumeError(Error Err)
Consume a Error without doing anything.
Definition: Error.h:1001
void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner={})
Log all errors (if any) in E to OS.
Definition: Error.cpp:61
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.
Definition: Error.h:326
int64_t Addend
Addend - the relocation addend encoded in the instruction itself.
uint32_t RelType
RelType - relocation type.
Expected< relocation_iterator > processScatteredVANILLA(unsigned SectionID, relocation_iterator RelI, const ObjectFile &BaseObjT, RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID, bool TargetIsLocalThumbFunc=false)
Process a scattered vanilla relocation.
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
size_t getSize() const
#define RTDYLD_INVALID_SECTION_ID
unsigned getAnyRelocationLength(const MachO::any_relocation_info &RE) const
uint64_t Offset
Offset - offset into the section.
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
uint64_t getLoadAddress() const
uint32_t Size
Definition: Profile.cpp:46
section_iterator section_begin() const override
std::unique_ptr< RuntimeDyld::LoadedObjectInfo > loadObject(const object::ObjectFile &O) override
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.
LLVM_NODISCARD const char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:136
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
A raw_ostream that writes to an std::string.
Definition: raw_ostream.h:503
LLVM Value Representation.
Definition: Value.h:74
Lightweight error class with error context and mandatory checking.
Definition: Error.h:157
unsigned Size
The size of this relocation (MachO specific).
section_iterator section_end() const override
Error populateIndirectSymbolPointersSection(const MachOObjectFile &Obj, const SectionRef &PTSection, unsigned PTSectionID)
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
bool isMachO() const
Definition: Binary.h:122
void makeValueAddendPCRel(RelocationValueRef &Value, const relocation_iterator &RI, unsigned OffsetToNextPC)
Make the RelocationValueRef addend PC-relative.
#define LLVM_DEBUG(X)
Definition: Debug.h:122
uint32_t getIndirectSymbolTableEntry(const MachO::dysymtab_command &DLC, unsigned Index) const
uint32_t getScatteredRelocationValue(const MachO::any_relocation_info &RE) const
This is a value type class that represents a single section in the list of sections in the object fil...
Definition: ObjectFile.h:81
MachO::dysymtab_command getDysymtabLoadCommand() const