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1 //===- MachO.h - MachO object file implementation ---------------*- 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 // This file declares the MachOObjectFile class, which implement the ObjectFile
11 // interface for MachO files.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_OBJECT_MACHO_H
16 #define LLVM_OBJECT_MACHO_H
17 
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/Object/ObjectFile.h"
22 #include "llvm/Support/MachO.h"
23 
24 namespace llvm {
25 namespace object {
26 
27 /// DiceRef - This is a value type class that represents a single
28 /// data in code entry in the table in a Mach-O object file.
29 class DiceRef {
30   DataRefImpl DicePimpl;
31   const ObjectFile *OwningObject;
32 
33 public:
DiceRef()34   DiceRef() : OwningObject(nullptr) { }
35 
36   DiceRef(DataRefImpl DiceP, const ObjectFile *Owner);
37 
38   bool operator==(const DiceRef &Other) const;
39   bool operator<(const DiceRef &Other) const;
40 
41   void moveNext();
42 
43   std::error_code getOffset(uint32_t &Result) const;
44   std::error_code getLength(uint16_t &Result) const;
45   std::error_code getKind(uint16_t &Result) const;
46 
47   DataRefImpl getRawDataRefImpl() const;
48   const ObjectFile *getObjectFile() const;
49 };
50 typedef content_iterator<DiceRef> dice_iterator;
51 
52 /// ExportEntry encapsulates the current-state-of-the-walk used when doing a
53 /// non-recursive walk of the trie data structure.  This allows you to iterate
54 /// across all exported symbols using:
55 ///      for (const llvm::object::ExportEntry &AnExport : Obj->exports()) {
56 ///      }
57 class ExportEntry {
58 public:
59   ExportEntry(ArrayRef<uint8_t> Trie);
60 
61   StringRef name() const;
62   uint64_t flags() const;
63   uint64_t address() const;
64   uint64_t other() const;
65   StringRef otherName() const;
66   uint32_t nodeOffset() const;
67 
68   bool operator==(const ExportEntry &) const;
69 
70   void moveNext();
71 
72 private:
73   friend class MachOObjectFile;
74   void moveToFirst();
75   void moveToEnd();
76   uint64_t readULEB128(const uint8_t *&p);
77   void pushDownUntilBottom();
78   void pushNode(uint64_t Offset);
79 
80   // Represents a node in the mach-o exports trie.
81   struct NodeState {
82     NodeState(const uint8_t *Ptr);
83     const uint8_t *Start;
84     const uint8_t *Current;
85     uint64_t Flags;
86     uint64_t Address;
87     uint64_t Other;
88     const char *ImportName;
89     unsigned ChildCount;
90     unsigned NextChildIndex;
91     unsigned ParentStringLength;
92     bool IsExportNode;
93   };
94 
95   ArrayRef<uint8_t> Trie;
96   SmallString<256> CumulativeString;
97   SmallVector<NodeState, 16> Stack;
98   bool Malformed;
99   bool Done;
100 };
101 typedef content_iterator<ExportEntry> export_iterator;
102 
103 /// MachORebaseEntry encapsulates the current state in the decompression of
104 /// rebasing opcodes. This allows you to iterate through the compressed table of
105 /// rebasing using:
106 ///    for (const llvm::object::MachORebaseEntry &Entry : Obj->rebaseTable()) {
107 ///    }
108 class MachORebaseEntry {
109 public:
110   MachORebaseEntry(ArrayRef<uint8_t> opcodes, bool is64Bit);
111 
112   uint32_t segmentIndex() const;
113   uint64_t segmentOffset() const;
114   StringRef typeName() const;
115 
116   bool operator==(const MachORebaseEntry &) const;
117 
118   void moveNext();
119 
120 private:
121   friend class MachOObjectFile;
122   void moveToFirst();
123   void moveToEnd();
124   uint64_t readULEB128();
125 
126   ArrayRef<uint8_t> Opcodes;
127   const uint8_t *Ptr;
128   uint64_t SegmentOffset;
129   uint32_t SegmentIndex;
130   uint64_t RemainingLoopCount;
131   uint64_t AdvanceAmount;
132   uint8_t  RebaseType;
133   uint8_t  PointerSize;
134   bool     Malformed;
135   bool     Done;
136 };
137 typedef content_iterator<MachORebaseEntry> rebase_iterator;
138 
139 /// MachOBindEntry encapsulates the current state in the decompression of
140 /// binding opcodes. This allows you to iterate through the compressed table of
141 /// bindings using:
142 ///    for (const llvm::object::MachOBindEntry &Entry : Obj->bindTable()) {
143 ///    }
144 class MachOBindEntry {
145 public:
146   enum class Kind { Regular, Lazy, Weak };
147 
148   MachOBindEntry(ArrayRef<uint8_t> Opcodes, bool is64Bit, MachOBindEntry::Kind);
149 
150   uint32_t segmentIndex() const;
151   uint64_t segmentOffset() const;
152   StringRef typeName() const;
153   StringRef symbolName() const;
154   uint32_t flags() const;
155   int64_t addend() const;
156   int ordinal() const;
157 
158   bool operator==(const MachOBindEntry &) const;
159 
160   void moveNext();
161 
162 private:
163   friend class MachOObjectFile;
164   void moveToFirst();
165   void moveToEnd();
166   uint64_t readULEB128();
167   int64_t readSLEB128();
168 
169   ArrayRef<uint8_t> Opcodes;
170   const uint8_t *Ptr;
171   uint64_t SegmentOffset;
172   uint32_t SegmentIndex;
173   StringRef SymbolName;
174   int      Ordinal;
175   uint32_t Flags;
176   int64_t  Addend;
177   uint64_t RemainingLoopCount;
178   uint64_t AdvanceAmount;
179   uint8_t  BindType;
180   uint8_t  PointerSize;
181   Kind     TableKind;
182   bool     Malformed;
183   bool     Done;
184 };
185 typedef content_iterator<MachOBindEntry> bind_iterator;
186 
187 class MachOObjectFile : public ObjectFile {
188 public:
189   struct LoadCommandInfo {
190     const char *Ptr;      // Where in memory the load command is.
191     MachO::load_command C; // The command itself.
192   };
193   typedef SmallVector<LoadCommandInfo, 4> LoadCommandList;
194   typedef LoadCommandList::const_iterator load_command_iterator;
195 
196   static Expected<std::unique_ptr<MachOObjectFile>>
197   create(MemoryBufferRef Object, bool IsLittleEndian, bool Is64Bits);
198 
199   void moveSymbolNext(DataRefImpl &Symb) const override;
200 
201   uint64_t getNValue(DataRefImpl Sym) const;
202   Expected<StringRef> getSymbolName(DataRefImpl Symb) const override;
203 
204   // MachO specific.
205   std::error_code getIndirectName(DataRefImpl Symb, StringRef &Res) const;
206   unsigned getSectionType(SectionRef Sec) const;
207 
208   Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const override;
209   uint32_t getSymbolAlignment(DataRefImpl Symb) const override;
210   uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const override;
211   Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const override;
212   uint32_t getSymbolFlags(DataRefImpl Symb) const override;
213   Expected<section_iterator> getSymbolSection(DataRefImpl Symb) const override;
214   unsigned getSymbolSectionID(SymbolRef Symb) const;
215   unsigned getSectionID(SectionRef Sec) const;
216 
217   void moveSectionNext(DataRefImpl &Sec) const override;
218   std::error_code getSectionName(DataRefImpl Sec,
219                                  StringRef &Res) const override;
220   uint64_t getSectionAddress(DataRefImpl Sec) const override;
221   uint64_t getSectionSize(DataRefImpl Sec) const override;
222   std::error_code getSectionContents(DataRefImpl Sec,
223                                      StringRef &Res) const override;
224   uint64_t getSectionAlignment(DataRefImpl Sec) const override;
225   bool isSectionCompressed(DataRefImpl Sec) const override;
226   bool isSectionText(DataRefImpl Sec) const override;
227   bool isSectionData(DataRefImpl Sec) const override;
228   bool isSectionBSS(DataRefImpl Sec) const override;
229   bool isSectionVirtual(DataRefImpl Sec) const override;
230   bool isSectionBitcode(DataRefImpl Sec) const override;
231   relocation_iterator section_rel_begin(DataRefImpl Sec) const override;
232   relocation_iterator section_rel_end(DataRefImpl Sec) const override;
233 
234   void moveRelocationNext(DataRefImpl &Rel) const override;
235   uint64_t getRelocationOffset(DataRefImpl Rel) const override;
236   symbol_iterator getRelocationSymbol(DataRefImpl Rel) const override;
237   section_iterator getRelocationSection(DataRefImpl Rel) const;
238   uint64_t getRelocationType(DataRefImpl Rel) const override;
239   void getRelocationTypeName(DataRefImpl Rel,
240                              SmallVectorImpl<char> &Result) const override;
241   uint8_t getRelocationLength(DataRefImpl Rel) const;
242 
243   // MachO specific.
244   std::error_code getLibraryShortNameByIndex(unsigned Index, StringRef &) const;
245 
246   section_iterator getRelocationRelocatedSection(relocation_iterator Rel) const;
247 
248   // TODO: Would be useful to have an iterator based version
249   // of the load command interface too.
250 
251   basic_symbol_iterator symbol_begin_impl() const override;
252   basic_symbol_iterator symbol_end_impl() const override;
253 
254   // MachO specific.
255   basic_symbol_iterator getSymbolByIndex(unsigned Index) const;
256   uint64_t getSymbolIndex(DataRefImpl Symb) const;
257 
258   section_iterator section_begin() const override;
259   section_iterator section_end() const override;
260 
261   uint8_t getBytesInAddress() const override;
262 
263   StringRef getFileFormatName() const override;
264   unsigned getArch() const override;
getFeatures()265   SubtargetFeatures getFeatures() const override { return SubtargetFeatures(); }
266   Triple getArchTriple(const char **McpuDefault = nullptr) const;
267 
268   relocation_iterator section_rel_begin(unsigned Index) const;
269   relocation_iterator section_rel_end(unsigned Index) const;
270 
271   dice_iterator begin_dices() const;
272   dice_iterator end_dices() const;
273 
274   load_command_iterator begin_load_commands() const;
275   load_command_iterator end_load_commands() const;
276   iterator_range<load_command_iterator> load_commands() const;
277 
278   /// For use iterating over all exported symbols.
279   iterator_range<export_iterator> exports() const;
280 
281   /// For use examining a trie not in a MachOObjectFile.
282   static iterator_range<export_iterator> exports(ArrayRef<uint8_t> Trie);
283 
284   /// For use iterating over all rebase table entries.
285   iterator_range<rebase_iterator> rebaseTable() const;
286 
287   /// For use examining rebase opcodes not in a MachOObjectFile.
288   static iterator_range<rebase_iterator> rebaseTable(ArrayRef<uint8_t> Opcodes,
289                                                      bool is64);
290 
291   /// For use iterating over all bind table entries.
292   iterator_range<bind_iterator> bindTable() const;
293 
294   /// For use iterating over all lazy bind table entries.
295   iterator_range<bind_iterator> lazyBindTable() const;
296 
297   /// For use iterating over all lazy bind table entries.
298   iterator_range<bind_iterator> weakBindTable() const;
299 
300   /// For use examining bind opcodes not in a MachOObjectFile.
301   static iterator_range<bind_iterator> bindTable(ArrayRef<uint8_t> Opcodes,
302                                                  bool is64,
303                                                  MachOBindEntry::Kind);
304 
305 
306   // In a MachO file, sections have a segment name. This is used in the .o
307   // files. They have a single segment, but this field specifies which segment
308   // a section should be put in in the final object.
309   StringRef getSectionFinalSegmentName(DataRefImpl Sec) const;
310 
311   // Names are stored as 16 bytes. These returns the raw 16 bytes without
312   // interpreting them as a C string.
313   ArrayRef<char> getSectionRawName(DataRefImpl Sec) const;
314   ArrayRef<char> getSectionRawFinalSegmentName(DataRefImpl Sec) const;
315 
316   // MachO specific Info about relocations.
317   bool isRelocationScattered(const MachO::any_relocation_info &RE) const;
318   unsigned getPlainRelocationSymbolNum(
319                                     const MachO::any_relocation_info &RE) const;
320   bool getPlainRelocationExternal(const MachO::any_relocation_info &RE) const;
321   bool getScatteredRelocationScattered(
322                                     const MachO::any_relocation_info &RE) const;
323   uint32_t getScatteredRelocationValue(
324                                     const MachO::any_relocation_info &RE) const;
325   uint32_t getScatteredRelocationType(
326                                     const MachO::any_relocation_info &RE) const;
327   unsigned getAnyRelocationAddress(const MachO::any_relocation_info &RE) const;
328   unsigned getAnyRelocationPCRel(const MachO::any_relocation_info &RE) const;
329   unsigned getAnyRelocationLength(const MachO::any_relocation_info &RE) const;
330   unsigned getAnyRelocationType(const MachO::any_relocation_info &RE) const;
331   SectionRef getAnyRelocationSection(const MachO::any_relocation_info &RE) const;
332 
333   // MachO specific structures.
334   MachO::section getSection(DataRefImpl DRI) const;
335   MachO::section_64 getSection64(DataRefImpl DRI) const;
336   MachO::section getSection(const LoadCommandInfo &L, unsigned Index) const;
337   MachO::section_64 getSection64(const LoadCommandInfo &L,unsigned Index) const;
338   MachO::nlist getSymbolTableEntry(DataRefImpl DRI) const;
339   MachO::nlist_64 getSymbol64TableEntry(DataRefImpl DRI) const;
340 
341   MachO::linkedit_data_command
342   getLinkeditDataLoadCommand(const LoadCommandInfo &L) const;
343   MachO::segment_command
344   getSegmentLoadCommand(const LoadCommandInfo &L) const;
345   MachO::segment_command_64
346   getSegment64LoadCommand(const LoadCommandInfo &L) const;
347   MachO::linker_option_command
348   getLinkerOptionLoadCommand(const LoadCommandInfo &L) const;
349   MachO::version_min_command
350   getVersionMinLoadCommand(const LoadCommandInfo &L) const;
351   MachO::dylib_command
352   getDylibIDLoadCommand(const LoadCommandInfo &L) const;
353   MachO::dyld_info_command
354   getDyldInfoLoadCommand(const LoadCommandInfo &L) const;
355   MachO::dylinker_command
356   getDylinkerCommand(const LoadCommandInfo &L) const;
357   MachO::uuid_command
358   getUuidCommand(const LoadCommandInfo &L) const;
359   MachO::rpath_command
360   getRpathCommand(const LoadCommandInfo &L) const;
361   MachO::source_version_command
362   getSourceVersionCommand(const LoadCommandInfo &L) const;
363   MachO::entry_point_command
364   getEntryPointCommand(const LoadCommandInfo &L) const;
365   MachO::encryption_info_command
366   getEncryptionInfoCommand(const LoadCommandInfo &L) const;
367   MachO::encryption_info_command_64
368   getEncryptionInfoCommand64(const LoadCommandInfo &L) const;
369   MachO::sub_framework_command
370   getSubFrameworkCommand(const LoadCommandInfo &L) const;
371   MachO::sub_umbrella_command
372   getSubUmbrellaCommand(const LoadCommandInfo &L) const;
373   MachO::sub_library_command
374   getSubLibraryCommand(const LoadCommandInfo &L) const;
375   MachO::sub_client_command
376   getSubClientCommand(const LoadCommandInfo &L) const;
377   MachO::routines_command
378   getRoutinesCommand(const LoadCommandInfo &L) const;
379   MachO::routines_command_64
380   getRoutinesCommand64(const LoadCommandInfo &L) const;
381   MachO::thread_command
382   getThreadCommand(const LoadCommandInfo &L) const;
383 
384   MachO::any_relocation_info getRelocation(DataRefImpl Rel) const;
385   MachO::data_in_code_entry getDice(DataRefImpl Rel) const;
386   const MachO::mach_header &getHeader() const;
387   const MachO::mach_header_64 &getHeader64() const;
388   uint32_t
389   getIndirectSymbolTableEntry(const MachO::dysymtab_command &DLC,
390                               unsigned Index) const;
391   MachO::data_in_code_entry getDataInCodeTableEntry(uint32_t DataOffset,
392                                                     unsigned Index) const;
393   MachO::symtab_command getSymtabLoadCommand() const;
394   MachO::dysymtab_command getDysymtabLoadCommand() const;
395   MachO::linkedit_data_command getDataInCodeLoadCommand() const;
396   MachO::linkedit_data_command getLinkOptHintsLoadCommand() const;
397   ArrayRef<uint8_t> getDyldInfoRebaseOpcodes() const;
398   ArrayRef<uint8_t> getDyldInfoBindOpcodes() const;
399   ArrayRef<uint8_t> getDyldInfoWeakBindOpcodes() const;
400   ArrayRef<uint8_t> getDyldInfoLazyBindOpcodes() const;
401   ArrayRef<uint8_t> getDyldInfoExportsTrie() const;
402   ArrayRef<uint8_t> getUuid() const;
403 
404   StringRef getStringTableData() const;
405   bool is64Bit() const;
406   void ReadULEB128s(uint64_t Index, SmallVectorImpl<uint64_t> &Out) const;
407 
408   static StringRef guessLibraryShortName(StringRef Name, bool &isFramework,
409                                          StringRef &Suffix);
410 
411   static Triple::ArchType getArch(uint32_t CPUType);
412   static Triple getArchTriple(uint32_t CPUType, uint32_t CPUSubType,
413                               const char **McpuDefault = nullptr);
414   static bool isValidArch(StringRef ArchFlag);
415   static Triple getHostArch();
416 
417   bool isRelocatableObject() const override;
418 
hasPageZeroSegment()419   bool hasPageZeroSegment() const { return HasPageZeroSegment; }
420 
classof(const Binary * v)421   static bool classof(const Binary *v) {
422     return v->isMachO();
423   }
424 
425   static uint32_t
getVersionMinMajor(MachO::version_min_command & C,bool SDK)426   getVersionMinMajor(MachO::version_min_command &C, bool SDK) {
427     uint32_t VersionOrSDK = (SDK) ? C.sdk : C.version;
428     return (VersionOrSDK >> 16) & 0xffff;
429   }
430 
431   static uint32_t
getVersionMinMinor(MachO::version_min_command & C,bool SDK)432   getVersionMinMinor(MachO::version_min_command &C, bool SDK) {
433     uint32_t VersionOrSDK = (SDK) ? C.sdk : C.version;
434     return (VersionOrSDK >> 8) & 0xff;
435   }
436 
437   static uint32_t
getVersionMinUpdate(MachO::version_min_command & C,bool SDK)438   getVersionMinUpdate(MachO::version_min_command &C, bool SDK) {
439     uint32_t VersionOrSDK = (SDK) ? C.sdk : C.version;
440     return VersionOrSDK & 0xff;
441   }
442 
443 private:
444 
445   MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian, bool Is64Bits,
446                   Error &Err);
447 
448   uint64_t getSymbolValueImpl(DataRefImpl Symb) const override;
449 
450   union {
451     MachO::mach_header_64 Header64;
452     MachO::mach_header Header;
453   };
454   typedef SmallVector<const char*, 1> SectionList;
455   SectionList Sections;
456   typedef SmallVector<const char*, 1> LibraryList;
457   LibraryList Libraries;
458   LoadCommandList LoadCommands;
459   typedef SmallVector<StringRef, 1> LibraryShortName;
460   mutable LibraryShortName LibrariesShortNames;
461   const char *SymtabLoadCmd;
462   const char *DysymtabLoadCmd;
463   const char *DataInCodeLoadCmd;
464   const char *LinkOptHintsLoadCmd;
465   const char *DyldInfoLoadCmd;
466   const char *UuidLoadCmd;
467   bool HasPageZeroSegment;
468 };
469 
470 /// DiceRef
DiceRef(DataRefImpl DiceP,const ObjectFile * Owner)471 inline DiceRef::DiceRef(DataRefImpl DiceP, const ObjectFile *Owner)
472   : DicePimpl(DiceP) , OwningObject(Owner) {}
473 
474 inline bool DiceRef::operator==(const DiceRef &Other) const {
475   return DicePimpl == Other.DicePimpl;
476 }
477 
478 inline bool DiceRef::operator<(const DiceRef &Other) const {
479   return DicePimpl < Other.DicePimpl;
480 }
481 
moveNext()482 inline void DiceRef::moveNext() {
483   const MachO::data_in_code_entry *P =
484     reinterpret_cast<const MachO::data_in_code_entry *>(DicePimpl.p);
485   DicePimpl.p = reinterpret_cast<uintptr_t>(P + 1);
486 }
487 
488 // Since a Mach-O data in code reference, a DiceRef, can only be created when
489 // the OwningObject ObjectFile is a MachOObjectFile a static_cast<> is used for
490 // the methods that get the values of the fields of the reference.
491 
getOffset(uint32_t & Result)492 inline std::error_code DiceRef::getOffset(uint32_t &Result) const {
493   const MachOObjectFile *MachOOF =
494     static_cast<const MachOObjectFile *>(OwningObject);
495   MachO::data_in_code_entry Dice = MachOOF->getDice(DicePimpl);
496   Result = Dice.offset;
497   return std::error_code();
498 }
499 
getLength(uint16_t & Result)500 inline std::error_code DiceRef::getLength(uint16_t &Result) const {
501   const MachOObjectFile *MachOOF =
502     static_cast<const MachOObjectFile *>(OwningObject);
503   MachO::data_in_code_entry Dice = MachOOF->getDice(DicePimpl);
504   Result = Dice.length;
505   return std::error_code();
506 }
507 
getKind(uint16_t & Result)508 inline std::error_code DiceRef::getKind(uint16_t &Result) const {
509   const MachOObjectFile *MachOOF =
510     static_cast<const MachOObjectFile *>(OwningObject);
511   MachO::data_in_code_entry Dice = MachOOF->getDice(DicePimpl);
512   Result = Dice.kind;
513   return std::error_code();
514 }
515 
getRawDataRefImpl()516 inline DataRefImpl DiceRef::getRawDataRefImpl() const {
517   return DicePimpl;
518 }
519 
getObjectFile()520 inline const ObjectFile *DiceRef::getObjectFile() const {
521   return OwningObject;
522 }
523 
524 }
525 }
526 
527 #endif
528