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1 //===- ObjectFile.h - File format independent object file -------*- 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 a file format independent ObjectFile class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_OBJECT_OBJECTFILE_H
15 #define LLVM_OBJECT_OBJECTFILE_H
16 
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/MC/SubtargetFeature.h"
19 #include "llvm/Object/SymbolicFile.h"
20 #include "llvm/Support/DataTypes.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/FileSystem.h"
23 #include "llvm/Support/MemoryBuffer.h"
24 #include <cstring>
25 
26 namespace llvm {
27 namespace object {
28 
29 class ObjectFile;
30 class COFFObjectFile;
31 class MachOObjectFile;
32 
33 class SymbolRef;
34 class symbol_iterator;
35 class SectionRef;
36 typedef content_iterator<SectionRef> section_iterator;
37 
38 /// This is a value type class that represents a single relocation in the list
39 /// of relocations in the object file.
40 class RelocationRef {
41   DataRefImpl RelocationPimpl;
42   const ObjectFile *OwningObject;
43 
44 public:
RelocationRef()45   RelocationRef() : OwningObject(nullptr) { }
46 
47   RelocationRef(DataRefImpl RelocationP, const ObjectFile *Owner);
48 
49   bool operator==(const RelocationRef &Other) const;
50 
51   void moveNext();
52 
53   uint64_t getOffset() const;
54   symbol_iterator getSymbol() const;
55   uint64_t getType() const;
56 
57   /// @brief Get a string that represents the type of this relocation.
58   ///
59   /// This is for display purposes only.
60   void getTypeName(SmallVectorImpl<char> &Result) const;
61 
62   DataRefImpl getRawDataRefImpl() const;
63   const ObjectFile *getObject() const;
64 };
65 typedef content_iterator<RelocationRef> relocation_iterator;
66 
67 /// This is a value type class that represents a single section in the list of
68 /// sections in the object file.
69 class SectionRef {
70   friend class SymbolRef;
71   DataRefImpl SectionPimpl;
72   const ObjectFile *OwningObject;
73 
74 public:
SectionRef()75   SectionRef() : OwningObject(nullptr) { }
76 
77   SectionRef(DataRefImpl SectionP, const ObjectFile *Owner);
78 
79   bool operator==(const SectionRef &Other) const;
80   bool operator!=(const SectionRef &Other) const;
81   bool operator<(const SectionRef &Other) const;
82 
83   void moveNext();
84 
85   std::error_code getName(StringRef &Result) const;
86   uint64_t getAddress() const;
87   uint64_t getSize() const;
88   std::error_code getContents(StringRef &Result) const;
89 
90   /// @brief Get the alignment of this section as the actual value (not log 2).
91   uint64_t getAlignment() const;
92 
93   bool isCompressed() const;
94   bool isText() const;
95   bool isData() const;
96   bool isBSS() const;
97   bool isVirtual() const;
98   bool isBitcode() const;
99 
100   bool containsSymbol(SymbolRef S) const;
101 
102   relocation_iterator relocation_begin() const;
103   relocation_iterator relocation_end() const;
relocations()104   iterator_range<relocation_iterator> relocations() const {
105     return make_range(relocation_begin(), relocation_end());
106   }
107   section_iterator getRelocatedSection() const;
108 
109   DataRefImpl getRawDataRefImpl() const;
110   const ObjectFile *getObject() const;
111 };
112 
113 /// This is a value type class that represents a single symbol in the list of
114 /// symbols in the object file.
115 class SymbolRef : public BasicSymbolRef {
116   friend class SectionRef;
117 
118 public:
SymbolRef()119   SymbolRef() : BasicSymbolRef() {}
120 
121   enum Type {
122     ST_Unknown, // Type not specified
123     ST_Data,
124     ST_Debug,
125     ST_File,
126     ST_Function,
127     ST_Other
128   };
129 
130   SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);
SymbolRef(const BasicSymbolRef & B)131   SymbolRef(const BasicSymbolRef &B) : BasicSymbolRef(B) {
132     assert(isa<ObjectFile>(BasicSymbolRef::getObject()));
133   }
134 
135   Expected<StringRef> getName() const;
136   /// Returns the symbol virtual address (i.e. address at which it will be
137   /// mapped).
138   Expected<uint64_t> getAddress() const;
139 
140   /// Return the value of the symbol depending on the object this can be an
141   /// offset or a virtual address.
142   uint64_t getValue() const;
143 
144   /// @brief Get the alignment of this symbol as the actual value (not log 2).
145   uint32_t getAlignment() const;
146   uint64_t getCommonSize() const;
147   Expected<SymbolRef::Type> getType() const;
148 
149   /// @brief Get section this symbol is defined in reference to. Result is
150   /// end_sections() if it is undefined or is an absolute symbol.
151   Expected<section_iterator> getSection() const;
152 
153   const ObjectFile *getObject() const;
154 };
155 
156 class symbol_iterator : public basic_symbol_iterator {
157 public:
symbol_iterator(SymbolRef Sym)158   symbol_iterator(SymbolRef Sym) : basic_symbol_iterator(Sym) {}
symbol_iterator(const basic_symbol_iterator & B)159   symbol_iterator(const basic_symbol_iterator &B)
160       : basic_symbol_iterator(SymbolRef(B->getRawDataRefImpl(),
161                                         cast<ObjectFile>(B->getObject()))) {}
162 
163   const SymbolRef *operator->() const {
164     const BasicSymbolRef &P = basic_symbol_iterator::operator *();
165     return static_cast<const SymbolRef*>(&P);
166   }
167 
168   const SymbolRef &operator*() const {
169     const BasicSymbolRef &P = basic_symbol_iterator::operator *();
170     return static_cast<const SymbolRef&>(P);
171   }
172 };
173 
174 /// This class is the base class for all object file types. Concrete instances
175 /// of this object are created by createObjectFile, which figures out which type
176 /// to create.
177 class ObjectFile : public SymbolicFile {
178   virtual void anchor();
179   ObjectFile() = delete;
180   ObjectFile(const ObjectFile &other) = delete;
181 
182 protected:
183   ObjectFile(unsigned int Type, MemoryBufferRef Source);
184 
base()185   const uint8_t *base() const {
186     return reinterpret_cast<const uint8_t *>(Data.getBufferStart());
187   }
188 
189   // These functions are for SymbolRef to call internally. The main goal of
190   // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol
191   // entry in the memory mapped object file. SymbolPimpl cannot contain any
192   // virtual functions because then it could not point into the memory mapped
193   // file.
194   //
195   // Implementations assume that the DataRefImpl is valid and has not been
196   // modified externally. It's UB otherwise.
197   friend class SymbolRef;
198   virtual Expected<StringRef> getSymbolName(DataRefImpl Symb) const = 0;
199   std::error_code printSymbolName(raw_ostream &OS,
200                                   DataRefImpl Symb) const override;
201   virtual Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const = 0;
202   virtual uint64_t getSymbolValueImpl(DataRefImpl Symb) const = 0;
203   virtual uint32_t getSymbolAlignment(DataRefImpl Symb) const;
204   virtual uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const = 0;
205   virtual Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const = 0;
206   virtual Expected<section_iterator>
207   getSymbolSection(DataRefImpl Symb) const = 0;
208 
209   // Same as above for SectionRef.
210   friend class SectionRef;
211   virtual void moveSectionNext(DataRefImpl &Sec) const = 0;
212   virtual std::error_code getSectionName(DataRefImpl Sec,
213                                          StringRef &Res) const = 0;
214   virtual uint64_t getSectionAddress(DataRefImpl Sec) const = 0;
215   virtual uint64_t getSectionSize(DataRefImpl Sec) const = 0;
216   virtual std::error_code getSectionContents(DataRefImpl Sec,
217                                              StringRef &Res) const = 0;
218   virtual uint64_t getSectionAlignment(DataRefImpl Sec) const = 0;
219   virtual bool isSectionCompressed(DataRefImpl Sec) const = 0;
220   virtual bool isSectionText(DataRefImpl Sec) const = 0;
221   virtual bool isSectionData(DataRefImpl Sec) const = 0;
222   virtual bool isSectionBSS(DataRefImpl Sec) const = 0;
223   // A section is 'virtual' if its contents aren't present in the object image.
224   virtual bool isSectionVirtual(DataRefImpl Sec) const = 0;
225   virtual bool isSectionBitcode(DataRefImpl Sec) const;
226   virtual relocation_iterator section_rel_begin(DataRefImpl Sec) const = 0;
227   virtual relocation_iterator section_rel_end(DataRefImpl Sec) const = 0;
228   virtual section_iterator getRelocatedSection(DataRefImpl Sec) const;
229 
230   // Same as above for RelocationRef.
231   friend class RelocationRef;
232   virtual void moveRelocationNext(DataRefImpl &Rel) const = 0;
233   virtual uint64_t getRelocationOffset(DataRefImpl Rel) const = 0;
234   virtual symbol_iterator getRelocationSymbol(DataRefImpl Rel) const = 0;
235   virtual uint64_t getRelocationType(DataRefImpl Rel) const = 0;
236   virtual void getRelocationTypeName(DataRefImpl Rel,
237                                      SmallVectorImpl<char> &Result) const = 0;
238 
239   uint64_t getSymbolValue(DataRefImpl Symb) const;
240 
241 public:
getCommonSymbolSize(DataRefImpl Symb)242   uint64_t getCommonSymbolSize(DataRefImpl Symb) const {
243     assert(getSymbolFlags(Symb) & SymbolRef::SF_Common);
244     return getCommonSymbolSizeImpl(Symb);
245   }
246 
247   typedef iterator_range<symbol_iterator> symbol_iterator_range;
symbols()248   symbol_iterator_range symbols() const {
249     return symbol_iterator_range(symbol_begin(), symbol_end());
250   }
251 
252   virtual section_iterator section_begin() const = 0;
253   virtual section_iterator section_end() const = 0;
254 
255   typedef iterator_range<section_iterator> section_iterator_range;
sections()256   section_iterator_range sections() const {
257     return section_iterator_range(section_begin(), section_end());
258   }
259 
260   /// @brief The number of bytes used to represent an address in this object
261   ///        file format.
262   virtual uint8_t getBytesInAddress() const = 0;
263 
264   virtual StringRef getFileFormatName() const = 0;
265   virtual /* Triple::ArchType */ unsigned getArch() const = 0;
266   virtual SubtargetFeatures getFeatures() const = 0;
267 
268   /// Returns platform-specific object flags, if any.
getPlatformFlags(unsigned & Result)269   virtual std::error_code getPlatformFlags(unsigned &Result) const {
270     Result = 0;
271     return object_error::invalid_file_type;
272   }
273 
274   /// True if this is a relocatable object (.o/.obj).
275   virtual bool isRelocatableObject() const = 0;
276 
277   /// @returns Pointer to ObjectFile subclass to handle this type of object.
278   /// @param ObjectPath The path to the object file. ObjectPath.isObject must
279   ///        return true.
280   /// @brief Create ObjectFile from path.
281   static Expected<OwningBinary<ObjectFile>>
282   createObjectFile(StringRef ObjectPath);
283 
284   static Expected<std::unique_ptr<ObjectFile>>
285   createObjectFile(MemoryBufferRef Object, sys::fs::file_magic Type);
286   static Expected<std::unique_ptr<ObjectFile>>
createObjectFile(MemoryBufferRef Object)287   createObjectFile(MemoryBufferRef Object) {
288     return createObjectFile(Object, sys::fs::file_magic::unknown);
289   }
290 
291 
classof(const Binary * v)292   static inline bool classof(const Binary *v) {
293     return v->isObject();
294   }
295 
296   static ErrorOr<std::unique_ptr<COFFObjectFile>>
297   createCOFFObjectFile(MemoryBufferRef Object);
298 
299   static ErrorOr<std::unique_ptr<ObjectFile>>
300   createELFObjectFile(MemoryBufferRef Object);
301 
302   static Expected<std::unique_ptr<MachOObjectFile>>
303   createMachOObjectFile(MemoryBufferRef Object);
304 
305 };
306 
307 // Inline function definitions.
SymbolRef(DataRefImpl SymbolP,const ObjectFile * Owner)308 inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner)
309     : BasicSymbolRef(SymbolP, Owner) {}
310 
getName()311 inline Expected<StringRef> SymbolRef::getName() const {
312   return getObject()->getSymbolName(getRawDataRefImpl());
313 }
314 
getAddress()315 inline Expected<uint64_t> SymbolRef::getAddress() const {
316   return getObject()->getSymbolAddress(getRawDataRefImpl());
317 }
318 
getValue()319 inline uint64_t SymbolRef::getValue() const {
320   return getObject()->getSymbolValue(getRawDataRefImpl());
321 }
322 
getAlignment()323 inline uint32_t SymbolRef::getAlignment() const {
324   return getObject()->getSymbolAlignment(getRawDataRefImpl());
325 }
326 
getCommonSize()327 inline uint64_t SymbolRef::getCommonSize() const {
328   return getObject()->getCommonSymbolSize(getRawDataRefImpl());
329 }
330 
getSection()331 inline Expected<section_iterator> SymbolRef::getSection() const {
332   return getObject()->getSymbolSection(getRawDataRefImpl());
333 }
334 
getType()335 inline Expected<SymbolRef::Type> SymbolRef::getType() const {
336   return getObject()->getSymbolType(getRawDataRefImpl());
337 }
338 
getObject()339 inline const ObjectFile *SymbolRef::getObject() const {
340   const SymbolicFile *O = BasicSymbolRef::getObject();
341   return cast<ObjectFile>(O);
342 }
343 
344 
345 /// SectionRef
SectionRef(DataRefImpl SectionP,const ObjectFile * Owner)346 inline SectionRef::SectionRef(DataRefImpl SectionP,
347                               const ObjectFile *Owner)
348   : SectionPimpl(SectionP)
349   , OwningObject(Owner) {}
350 
351 inline bool SectionRef::operator==(const SectionRef &Other) const {
352   return SectionPimpl == Other.SectionPimpl;
353 }
354 
355 inline bool SectionRef::operator!=(const SectionRef &Other) const {
356   return SectionPimpl != Other.SectionPimpl;
357 }
358 
359 inline bool SectionRef::operator<(const SectionRef &Other) const {
360   return SectionPimpl < Other.SectionPimpl;
361 }
362 
moveNext()363 inline void SectionRef::moveNext() {
364   return OwningObject->moveSectionNext(SectionPimpl);
365 }
366 
getName(StringRef & Result)367 inline std::error_code SectionRef::getName(StringRef &Result) const {
368   return OwningObject->getSectionName(SectionPimpl, Result);
369 }
370 
getAddress()371 inline uint64_t SectionRef::getAddress() const {
372   return OwningObject->getSectionAddress(SectionPimpl);
373 }
374 
getSize()375 inline uint64_t SectionRef::getSize() const {
376   return OwningObject->getSectionSize(SectionPimpl);
377 }
378 
getContents(StringRef & Result)379 inline std::error_code SectionRef::getContents(StringRef &Result) const {
380   return OwningObject->getSectionContents(SectionPimpl, Result);
381 }
382 
getAlignment()383 inline uint64_t SectionRef::getAlignment() const {
384   return OwningObject->getSectionAlignment(SectionPimpl);
385 }
386 
isCompressed()387 inline bool SectionRef::isCompressed() const {
388   return OwningObject->isSectionCompressed(SectionPimpl);
389 }
390 
isText()391 inline bool SectionRef::isText() const {
392   return OwningObject->isSectionText(SectionPimpl);
393 }
394 
isData()395 inline bool SectionRef::isData() const {
396   return OwningObject->isSectionData(SectionPimpl);
397 }
398 
isBSS()399 inline bool SectionRef::isBSS() const {
400   return OwningObject->isSectionBSS(SectionPimpl);
401 }
402 
isVirtual()403 inline bool SectionRef::isVirtual() const {
404   return OwningObject->isSectionVirtual(SectionPimpl);
405 }
406 
isBitcode()407 inline bool SectionRef::isBitcode() const {
408   return OwningObject->isSectionBitcode(SectionPimpl);
409 }
410 
relocation_begin()411 inline relocation_iterator SectionRef::relocation_begin() const {
412   return OwningObject->section_rel_begin(SectionPimpl);
413 }
414 
relocation_end()415 inline relocation_iterator SectionRef::relocation_end() const {
416   return OwningObject->section_rel_end(SectionPimpl);
417 }
418 
getRelocatedSection()419 inline section_iterator SectionRef::getRelocatedSection() const {
420   return OwningObject->getRelocatedSection(SectionPimpl);
421 }
422 
getRawDataRefImpl()423 inline DataRefImpl SectionRef::getRawDataRefImpl() const {
424   return SectionPimpl;
425 }
426 
getObject()427 inline const ObjectFile *SectionRef::getObject() const {
428   return OwningObject;
429 }
430 
431 /// RelocationRef
RelocationRef(DataRefImpl RelocationP,const ObjectFile * Owner)432 inline RelocationRef::RelocationRef(DataRefImpl RelocationP,
433                               const ObjectFile *Owner)
434   : RelocationPimpl(RelocationP)
435   , OwningObject(Owner) {}
436 
437 inline bool RelocationRef::operator==(const RelocationRef &Other) const {
438   return RelocationPimpl == Other.RelocationPimpl;
439 }
440 
moveNext()441 inline void RelocationRef::moveNext() {
442   return OwningObject->moveRelocationNext(RelocationPimpl);
443 }
444 
getOffset()445 inline uint64_t RelocationRef::getOffset() const {
446   return OwningObject->getRelocationOffset(RelocationPimpl);
447 }
448 
getSymbol()449 inline symbol_iterator RelocationRef::getSymbol() const {
450   return OwningObject->getRelocationSymbol(RelocationPimpl);
451 }
452 
getType()453 inline uint64_t RelocationRef::getType() const {
454   return OwningObject->getRelocationType(RelocationPimpl);
455 }
456 
getTypeName(SmallVectorImpl<char> & Result)457 inline void RelocationRef::getTypeName(SmallVectorImpl<char> &Result) const {
458   return OwningObject->getRelocationTypeName(RelocationPimpl, Result);
459 }
460 
getRawDataRefImpl()461 inline DataRefImpl RelocationRef::getRawDataRefImpl() const {
462   return RelocationPimpl;
463 }
464 
getObject()465 inline const ObjectFile *RelocationRef::getObject() const {
466   return OwningObject;
467 }
468 
469 
470 } // end namespace object
471 } // end namespace llvm
472 
473 #endif
474