1 //===- ObjectFile.h - File format independent object file -------*- 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 // This file declares a file format independent ObjectFile class.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #ifndef LLVM_OBJECT_OBJECTFILE_H
14 #define LLVM_OBJECT_OBJECTFILE_H
15
16 #include "llvm/ADT/DenseMapInfo.h"
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/ADT/Triple.h"
19 #include "llvm/ADT/iterator_range.h"
20 #include "llvm/BinaryFormat/Magic.h"
21 #include "llvm/MC/SubtargetFeature.h"
22 #include "llvm/Object/Binary.h"
23 #include "llvm/Object/Error.h"
24 #include "llvm/Object/SymbolicFile.h"
25 #include "llvm/Support/Casting.h"
26 #include "llvm/Support/Error.h"
27 #include "llvm/Support/FileSystem.h"
28 #include "llvm/Support/MemoryBuffer.h"
29 #include <cassert>
30 #include <cstdint>
31 #include <memory>
32 #include <system_error>
33
34 namespace llvm {
35
36 class ARMAttributeParser;
37
38 namespace object {
39
40 class COFFObjectFile;
41 class MachOObjectFile;
42 class ObjectFile;
43 class SectionRef;
44 class SymbolRef;
45 class symbol_iterator;
46 class WasmObjectFile;
47
48 using section_iterator = content_iterator<SectionRef>;
49
50 /// This is a value type class that represents a single relocation in the list
51 /// of relocations in the object file.
52 class RelocationRef {
53 DataRefImpl RelocationPimpl;
54 const ObjectFile *OwningObject = nullptr;
55
56 public:
57 RelocationRef() = default;
58 RelocationRef(DataRefImpl RelocationP, const ObjectFile *Owner);
59
60 bool operator==(const RelocationRef &Other) const;
61
62 void moveNext();
63
64 uint64_t getOffset() const;
65 symbol_iterator getSymbol() const;
66 uint64_t getType() const;
67
68 /// Get a string that represents the type of this relocation.
69 ///
70 /// This is for display purposes only.
71 void getTypeName(SmallVectorImpl<char> &Result) const;
72
73 DataRefImpl getRawDataRefImpl() const;
74 const ObjectFile *getObject() const;
75 };
76
77 using relocation_iterator = content_iterator<RelocationRef>;
78
79 /// This is a value type class that represents a single section in the list of
80 /// sections in the object file.
81 class SectionRef {
82 friend class SymbolRef;
83
84 DataRefImpl SectionPimpl;
85 const ObjectFile *OwningObject = nullptr;
86
87 public:
88 SectionRef() = default;
89 SectionRef(DataRefImpl SectionP, const ObjectFile *Owner);
90
91 bool operator==(const SectionRef &Other) const;
92 bool operator!=(const SectionRef &Other) const;
93 bool operator<(const SectionRef &Other) const;
94
95 void moveNext();
96
97 Expected<StringRef> getName() const;
98 uint64_t getAddress() const;
99 uint64_t getIndex() const;
100 uint64_t getSize() const;
101 Expected<StringRef> getContents() const;
102
103 /// Get the alignment of this section as the actual value (not log 2).
104 uint64_t getAlignment() const;
105
106 bool isCompressed() const;
107 /// Whether this section contains instructions.
108 bool isText() const;
109 /// Whether this section contains data, not instructions.
110 bool isData() const;
111 /// Whether this section contains BSS uninitialized data.
112 bool isBSS() const;
113 bool isVirtual() const;
114 bool isBitcode() const;
115 bool isStripped() const;
116
117 /// Whether this section will be placed in the text segment, according to the
118 /// Berkeley size format. This is true if the section is allocatable, and
119 /// contains either code or readonly data.
120 bool isBerkeleyText() const;
121 /// Whether this section will be placed in the data segment, according to the
122 /// Berkeley size format. This is true if the section is allocatable and
123 /// contains data (e.g. PROGBITS), but is not text.
124 bool isBerkeleyData() const;
125
126 bool containsSymbol(SymbolRef S) const;
127
128 relocation_iterator relocation_begin() const;
129 relocation_iterator relocation_end() const;
relocations()130 iterator_range<relocation_iterator> relocations() const {
131 return make_range(relocation_begin(), relocation_end());
132 }
133 Expected<section_iterator> getRelocatedSection() const;
134
135 DataRefImpl getRawDataRefImpl() const;
136 const ObjectFile *getObject() const;
137 };
138
139 struct SectionedAddress {
140 const static uint64_t UndefSection = UINT64_MAX;
141
142 uint64_t Address = 0;
143 uint64_t SectionIndex = UndefSection;
144 };
145
146 inline bool operator<(const SectionedAddress &LHS,
147 const SectionedAddress &RHS) {
148 return std::tie(LHS.SectionIndex, LHS.Address) <
149 std::tie(RHS.SectionIndex, RHS.Address);
150 }
151
152 inline bool operator==(const SectionedAddress &LHS,
153 const SectionedAddress &RHS) {
154 return std::tie(LHS.SectionIndex, LHS.Address) ==
155 std::tie(RHS.SectionIndex, RHS.Address);
156 }
157
158 raw_ostream &operator<<(raw_ostream &OS, const SectionedAddress &Addr);
159
160 /// This is a value type class that represents a single symbol in the list of
161 /// symbols in the object file.
162 class SymbolRef : public BasicSymbolRef {
163 friend class SectionRef;
164
165 public:
166 enum Type {
167 ST_Unknown, // Type not specified
168 ST_Data,
169 ST_Debug,
170 ST_File,
171 ST_Function,
172 ST_Other
173 };
174
175 SymbolRef() = default;
176 SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);
SymbolRef(const BasicSymbolRef & B)177 SymbolRef(const BasicSymbolRef &B) : BasicSymbolRef(B) {
178 assert(isa<ObjectFile>(BasicSymbolRef::getObject()));
179 }
180
181 Expected<StringRef> getName() const;
182 /// Returns the symbol virtual address (i.e. address at which it will be
183 /// mapped).
184 Expected<uint64_t> getAddress() const;
185
186 /// Return the value of the symbol depending on the object this can be an
187 /// offset or a virtual address.
188 uint64_t getValue() const;
189
190 /// Get the alignment of this symbol as the actual value (not log 2).
191 uint32_t getAlignment() const;
192 uint64_t getCommonSize() const;
193 Expected<SymbolRef::Type> getType() const;
194
195 /// Get section this symbol is defined in reference to. Result is
196 /// end_sections() if it is undefined or is an absolute symbol.
197 Expected<section_iterator> getSection() const;
198
199 const ObjectFile *getObject() const;
200 };
201
202 class symbol_iterator : public basic_symbol_iterator {
203 public:
symbol_iterator(SymbolRef Sym)204 symbol_iterator(SymbolRef Sym) : basic_symbol_iterator(Sym) {}
symbol_iterator(const basic_symbol_iterator & B)205 symbol_iterator(const basic_symbol_iterator &B)
206 : basic_symbol_iterator(SymbolRef(B->getRawDataRefImpl(),
207 cast<ObjectFile>(B->getObject()))) {}
208
209 const SymbolRef *operator->() const {
210 const BasicSymbolRef &P = basic_symbol_iterator::operator *();
211 return static_cast<const SymbolRef*>(&P);
212 }
213
214 const SymbolRef &operator*() const {
215 const BasicSymbolRef &P = basic_symbol_iterator::operator *();
216 return static_cast<const SymbolRef&>(P);
217 }
218 };
219
220 /// This class is the base class for all object file types. Concrete instances
221 /// of this object are created by createObjectFile, which figures out which type
222 /// to create.
223 class ObjectFile : public SymbolicFile {
224 virtual void anchor();
225
226 protected:
227 ObjectFile(unsigned int Type, MemoryBufferRef Source);
228
base()229 const uint8_t *base() const {
230 return reinterpret_cast<const uint8_t *>(Data.getBufferStart());
231 }
232
233 // These functions are for SymbolRef to call internally. The main goal of
234 // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol
235 // entry in the memory mapped object file. SymbolPimpl cannot contain any
236 // virtual functions because then it could not point into the memory mapped
237 // file.
238 //
239 // Implementations assume that the DataRefImpl is valid and has not been
240 // modified externally. It's UB otherwise.
241 friend class SymbolRef;
242
243 virtual Expected<StringRef> getSymbolName(DataRefImpl Symb) const = 0;
244 Error printSymbolName(raw_ostream &OS,
245 DataRefImpl Symb) const override;
246 virtual Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const = 0;
247 virtual uint64_t getSymbolValueImpl(DataRefImpl Symb) const = 0;
248 virtual uint32_t getSymbolAlignment(DataRefImpl Symb) const;
249 virtual uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const = 0;
250 virtual Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const = 0;
251 virtual Expected<section_iterator>
252 getSymbolSection(DataRefImpl Symb) const = 0;
253
254 // Same as above for SectionRef.
255 friend class SectionRef;
256
257 virtual void moveSectionNext(DataRefImpl &Sec) const = 0;
258 virtual Expected<StringRef> getSectionName(DataRefImpl Sec) const = 0;
259 virtual uint64_t getSectionAddress(DataRefImpl Sec) const = 0;
260 virtual uint64_t getSectionIndex(DataRefImpl Sec) const = 0;
261 virtual uint64_t getSectionSize(DataRefImpl Sec) const = 0;
262 virtual Expected<ArrayRef<uint8_t>>
263 getSectionContents(DataRefImpl Sec) const = 0;
264 virtual uint64_t getSectionAlignment(DataRefImpl Sec) const = 0;
265 virtual bool isSectionCompressed(DataRefImpl Sec) const = 0;
266 virtual bool isSectionText(DataRefImpl Sec) const = 0;
267 virtual bool isSectionData(DataRefImpl Sec) const = 0;
268 virtual bool isSectionBSS(DataRefImpl Sec) const = 0;
269 // A section is 'virtual' if its contents aren't present in the object image.
270 virtual bool isSectionVirtual(DataRefImpl Sec) const = 0;
271 virtual bool isSectionBitcode(DataRefImpl Sec) const;
272 virtual bool isSectionStripped(DataRefImpl Sec) const;
273 virtual bool isBerkeleyText(DataRefImpl Sec) const;
274 virtual bool isBerkeleyData(DataRefImpl Sec) const;
275 virtual relocation_iterator section_rel_begin(DataRefImpl Sec) const = 0;
276 virtual relocation_iterator section_rel_end(DataRefImpl Sec) const = 0;
277 virtual Expected<section_iterator> getRelocatedSection(DataRefImpl Sec) const;
278
279 // Same as above for RelocationRef.
280 friend class RelocationRef;
281 virtual void moveRelocationNext(DataRefImpl &Rel) const = 0;
282 virtual uint64_t getRelocationOffset(DataRefImpl Rel) const = 0;
283 virtual symbol_iterator getRelocationSymbol(DataRefImpl Rel) const = 0;
284 virtual uint64_t getRelocationType(DataRefImpl Rel) const = 0;
285 virtual void getRelocationTypeName(DataRefImpl Rel,
286 SmallVectorImpl<char> &Result) const = 0;
287
288 uint64_t getSymbolValue(DataRefImpl Symb) const;
289
290 public:
291 ObjectFile() = delete;
292 ObjectFile(const ObjectFile &other) = delete;
293
getCommonSymbolSize(DataRefImpl Symb)294 uint64_t getCommonSymbolSize(DataRefImpl Symb) const {
295 assert(getSymbolFlags(Symb) & SymbolRef::SF_Common);
296 return getCommonSymbolSizeImpl(Symb);
297 }
298
dynamic_relocation_sections()299 virtual std::vector<SectionRef> dynamic_relocation_sections() const {
300 return std::vector<SectionRef>();
301 }
302
303 using symbol_iterator_range = iterator_range<symbol_iterator>;
symbols()304 symbol_iterator_range symbols() const {
305 return symbol_iterator_range(symbol_begin(), symbol_end());
306 }
307
308 virtual section_iterator section_begin() const = 0;
309 virtual section_iterator section_end() const = 0;
310
311 using section_iterator_range = iterator_range<section_iterator>;
sections()312 section_iterator_range sections() const {
313 return section_iterator_range(section_begin(), section_end());
314 }
315
316 /// The number of bytes used to represent an address in this object
317 /// file format.
318 virtual uint8_t getBytesInAddress() const = 0;
319
320 virtual StringRef getFileFormatName() const = 0;
321 virtual Triple::ArchType getArch() const = 0;
322 virtual SubtargetFeatures getFeatures() const = 0;
setARMSubArch(Triple & TheTriple)323 virtual void setARMSubArch(Triple &TheTriple) const { }
getStartAddress()324 virtual Expected<uint64_t> getStartAddress() const {
325 return errorCodeToError(object_error::parse_failed);
326 };
327
328 /// Create a triple from the data in this object file.
329 Triple makeTriple() const;
330
331 /// Maps a debug section name to a standard DWARF section name.
mapDebugSectionName(StringRef Name)332 virtual StringRef mapDebugSectionName(StringRef Name) const { return Name; }
333
334 /// True if this is a relocatable object (.o/.obj).
335 virtual bool isRelocatableObject() const = 0;
336
337 /// @returns Pointer to ObjectFile subclass to handle this type of object.
338 /// @param ObjectPath The path to the object file. ObjectPath.isObject must
339 /// return true.
340 /// Create ObjectFile from path.
341 static Expected<OwningBinary<ObjectFile>>
342 createObjectFile(StringRef ObjectPath);
343
344 static Expected<std::unique_ptr<ObjectFile>>
345 createObjectFile(MemoryBufferRef Object, llvm::file_magic Type);
346 static Expected<std::unique_ptr<ObjectFile>>
createObjectFile(MemoryBufferRef Object)347 createObjectFile(MemoryBufferRef Object) {
348 return createObjectFile(Object, llvm::file_magic::unknown);
349 }
350
classof(const Binary * v)351 static bool classof(const Binary *v) {
352 return v->isObject();
353 }
354
355 static Expected<std::unique_ptr<COFFObjectFile>>
356 createCOFFObjectFile(MemoryBufferRef Object);
357
358 static Expected<std::unique_ptr<ObjectFile>>
359 createXCOFFObjectFile(MemoryBufferRef Object, unsigned FileType);
360
361 static Expected<std::unique_ptr<ObjectFile>>
362 createELFObjectFile(MemoryBufferRef Object);
363
364 static Expected<std::unique_ptr<MachOObjectFile>>
365 createMachOObjectFile(MemoryBufferRef Object,
366 uint32_t UniversalCputype = 0,
367 uint32_t UniversalIndex = 0);
368
369 static Expected<std::unique_ptr<WasmObjectFile>>
370 createWasmObjectFile(MemoryBufferRef Object);
371 };
372
373 // Inline function definitions.
SymbolRef(DataRefImpl SymbolP,const ObjectFile * Owner)374 inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner)
375 : BasicSymbolRef(SymbolP, Owner) {}
376
getName()377 inline Expected<StringRef> SymbolRef::getName() const {
378 return getObject()->getSymbolName(getRawDataRefImpl());
379 }
380
getAddress()381 inline Expected<uint64_t> SymbolRef::getAddress() const {
382 return getObject()->getSymbolAddress(getRawDataRefImpl());
383 }
384
getValue()385 inline uint64_t SymbolRef::getValue() const {
386 return getObject()->getSymbolValue(getRawDataRefImpl());
387 }
388
getAlignment()389 inline uint32_t SymbolRef::getAlignment() const {
390 return getObject()->getSymbolAlignment(getRawDataRefImpl());
391 }
392
getCommonSize()393 inline uint64_t SymbolRef::getCommonSize() const {
394 return getObject()->getCommonSymbolSize(getRawDataRefImpl());
395 }
396
getSection()397 inline Expected<section_iterator> SymbolRef::getSection() const {
398 return getObject()->getSymbolSection(getRawDataRefImpl());
399 }
400
getType()401 inline Expected<SymbolRef::Type> SymbolRef::getType() const {
402 return getObject()->getSymbolType(getRawDataRefImpl());
403 }
404
getObject()405 inline const ObjectFile *SymbolRef::getObject() const {
406 const SymbolicFile *O = BasicSymbolRef::getObject();
407 return cast<ObjectFile>(O);
408 }
409
410 /// SectionRef
SectionRef(DataRefImpl SectionP,const ObjectFile * Owner)411 inline SectionRef::SectionRef(DataRefImpl SectionP,
412 const ObjectFile *Owner)
413 : SectionPimpl(SectionP)
414 , OwningObject(Owner) {}
415
416 inline bool SectionRef::operator==(const SectionRef &Other) const {
417 return OwningObject == Other.OwningObject &&
418 SectionPimpl == Other.SectionPimpl;
419 }
420
421 inline bool SectionRef::operator!=(const SectionRef &Other) const {
422 return !(*this == Other);
423 }
424
425 inline bool SectionRef::operator<(const SectionRef &Other) const {
426 assert(OwningObject == Other.OwningObject);
427 return SectionPimpl < Other.SectionPimpl;
428 }
429
moveNext()430 inline void SectionRef::moveNext() {
431 return OwningObject->moveSectionNext(SectionPimpl);
432 }
433
getName()434 inline Expected<StringRef> SectionRef::getName() const {
435 return OwningObject->getSectionName(SectionPimpl);
436 }
437
getAddress()438 inline uint64_t SectionRef::getAddress() const {
439 return OwningObject->getSectionAddress(SectionPimpl);
440 }
441
getIndex()442 inline uint64_t SectionRef::getIndex() const {
443 return OwningObject->getSectionIndex(SectionPimpl);
444 }
445
getSize()446 inline uint64_t SectionRef::getSize() const {
447 return OwningObject->getSectionSize(SectionPimpl);
448 }
449
getContents()450 inline Expected<StringRef> SectionRef::getContents() const {
451 Expected<ArrayRef<uint8_t>> Res =
452 OwningObject->getSectionContents(SectionPimpl);
453 if (!Res)
454 return Res.takeError();
455 return StringRef(reinterpret_cast<const char *>(Res->data()), Res->size());
456 }
457
getAlignment()458 inline uint64_t SectionRef::getAlignment() const {
459 return OwningObject->getSectionAlignment(SectionPimpl);
460 }
461
isCompressed()462 inline bool SectionRef::isCompressed() const {
463 return OwningObject->isSectionCompressed(SectionPimpl);
464 }
465
isText()466 inline bool SectionRef::isText() const {
467 return OwningObject->isSectionText(SectionPimpl);
468 }
469
isData()470 inline bool SectionRef::isData() const {
471 return OwningObject->isSectionData(SectionPimpl);
472 }
473
isBSS()474 inline bool SectionRef::isBSS() const {
475 return OwningObject->isSectionBSS(SectionPimpl);
476 }
477
isVirtual()478 inline bool SectionRef::isVirtual() const {
479 return OwningObject->isSectionVirtual(SectionPimpl);
480 }
481
isBitcode()482 inline bool SectionRef::isBitcode() const {
483 return OwningObject->isSectionBitcode(SectionPimpl);
484 }
485
isStripped()486 inline bool SectionRef::isStripped() const {
487 return OwningObject->isSectionStripped(SectionPimpl);
488 }
489
isBerkeleyText()490 inline bool SectionRef::isBerkeleyText() const {
491 return OwningObject->isBerkeleyText(SectionPimpl);
492 }
493
isBerkeleyData()494 inline bool SectionRef::isBerkeleyData() const {
495 return OwningObject->isBerkeleyData(SectionPimpl);
496 }
497
relocation_begin()498 inline relocation_iterator SectionRef::relocation_begin() const {
499 return OwningObject->section_rel_begin(SectionPimpl);
500 }
501
relocation_end()502 inline relocation_iterator SectionRef::relocation_end() const {
503 return OwningObject->section_rel_end(SectionPimpl);
504 }
505
getRelocatedSection()506 inline Expected<section_iterator> SectionRef::getRelocatedSection() const {
507 return OwningObject->getRelocatedSection(SectionPimpl);
508 }
509
getRawDataRefImpl()510 inline DataRefImpl SectionRef::getRawDataRefImpl() const {
511 return SectionPimpl;
512 }
513
getObject()514 inline const ObjectFile *SectionRef::getObject() const {
515 return OwningObject;
516 }
517
518 /// RelocationRef
RelocationRef(DataRefImpl RelocationP,const ObjectFile * Owner)519 inline RelocationRef::RelocationRef(DataRefImpl RelocationP,
520 const ObjectFile *Owner)
521 : RelocationPimpl(RelocationP)
522 , OwningObject(Owner) {}
523
524 inline bool RelocationRef::operator==(const RelocationRef &Other) const {
525 return RelocationPimpl == Other.RelocationPimpl;
526 }
527
moveNext()528 inline void RelocationRef::moveNext() {
529 return OwningObject->moveRelocationNext(RelocationPimpl);
530 }
531
getOffset()532 inline uint64_t RelocationRef::getOffset() const {
533 return OwningObject->getRelocationOffset(RelocationPimpl);
534 }
535
getSymbol()536 inline symbol_iterator RelocationRef::getSymbol() const {
537 return OwningObject->getRelocationSymbol(RelocationPimpl);
538 }
539
getType()540 inline uint64_t RelocationRef::getType() const {
541 return OwningObject->getRelocationType(RelocationPimpl);
542 }
543
getTypeName(SmallVectorImpl<char> & Result)544 inline void RelocationRef::getTypeName(SmallVectorImpl<char> &Result) const {
545 return OwningObject->getRelocationTypeName(RelocationPimpl, Result);
546 }
547
getRawDataRefImpl()548 inline DataRefImpl RelocationRef::getRawDataRefImpl() const {
549 return RelocationPimpl;
550 }
551
getObject()552 inline const ObjectFile *RelocationRef::getObject() const {
553 return OwningObject;
554 }
555
556 } // end namespace object
557
558 template <> struct DenseMapInfo<object::SectionRef> {
559 static bool isEqual(const object::SectionRef &A,
560 const object::SectionRef &B) {
561 return A == B;
562 }
563 static object::SectionRef getEmptyKey() {
564 return object::SectionRef({}, nullptr);
565 }
566 static object::SectionRef getTombstoneKey() {
567 object::DataRefImpl TS;
568 TS.p = (uintptr_t)-1;
569 return object::SectionRef(TS, nullptr);
570 }
571 static unsigned getHashValue(const object::SectionRef &Sec) {
572 object::DataRefImpl Raw = Sec.getRawDataRefImpl();
573 return hash_combine(Raw.p, Raw.d.a, Raw.d.b);
574 }
575 };
576
577 } // end namespace llvm
578
579 #endif // LLVM_OBJECT_OBJECTFILE_H
580