1 //===- lib/ReaderWriter/MachO/MachONormalizedFile.h -----------------------===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// \file These data structures comprise the "normalized" view of
12 /// mach-o object files. The normalized view is an in-memory only data structure
13 /// which is always in native endianness and pointer size.
15 /// The normalized view easily converts to and from YAML using YAML I/O.
17 /// The normalized view converts to and from binary mach-o object files using
18 /// the writeBinary() and readBinary() functions.
20 /// The normalized view converts to and from lld::Atoms using the
21 /// normalizedToAtoms() and normalizedFromAtoms().
23 /// Overall, the conversion paths available look like:
31 /// +------------+ +------+
32 /// | normalized | <-> | yaml |
33 /// +------------+ +------+
42 #ifndef LLD_READER_WRITER_MACHO_NORMALIZE_FILE_H
43 #define LLD_READER_WRITER_MACHO_NORMALIZE_FILE_H
45 #include "DebugInfo.h"
46 #include "lld/Common/LLVM.h"
47 #include "lld/Core/Error.h"
48 #include "lld/ReaderWriter/MachOLinkingContext.h"
49 #include "llvm/ADT/SmallString.h"
50 #include "llvm/ADT/StringRef.h"
51 #include "llvm/BinaryFormat/MachO.h"
52 #include "llvm/Support/Allocator.h"
53 #include "llvm/Support/Debug.h"
54 #include "llvm/Support/ErrorOr.h"
55 #include "llvm/Support/YAMLTraits.h"
57 using llvm::BumpPtrAllocator;
58 using llvm::yaml::Hex64;
59 using llvm::yaml::Hex32;
60 using llvm::yaml::Hex16;
61 using llvm::yaml::Hex8;
62 using llvm::yaml::SequenceTraits;
63 using llvm::MachO::HeaderFileType;
64 using llvm::MachO::BindType;
65 using llvm::MachO::RebaseType;
66 using llvm::MachO::NListType;
67 using llvm::MachO::RelocationInfoType;
68 using llvm::MachO::SectionType;
69 using llvm::MachO::LoadCommandType;
70 using llvm::MachO::ExportSymbolKind;
71 using llvm::MachO::DataRegionType;
75 namespace normalized {
78 /// The real mach-o relocation record is 8-bytes on disk and is
79 /// encoded in one of two different bit-field patterns. This
80 /// normalized form has the union of all possible fields.
82 Relocation() : offset(0), scattered(false),
83 type(llvm::MachO::GENERIC_RELOC_VANILLA),
84 length(0), pcRel(false), isExtern(false), value(0),
89 RelocationInfoType type;
97 /// A typedef so that YAML I/O can treat this vector as a sequence.
98 typedef std::vector<Relocation> Relocations;
100 /// A typedef so that YAML I/O can process the raw bytes in a section.
101 typedef std::vector<Hex8> ContentBytes;
103 /// A typedef so that YAML I/O can treat indirect symbols as a flow sequence.
104 typedef std::vector<uint32_t> IndirectSymbols;
106 /// A typedef so that YAML I/O can encode/decode section attributes.
107 LLVM_YAML_STRONG_TYPEDEF(uint32_t, SectionAttr)
109 /// A typedef so that YAML I/O can encode/decode section alignment.
110 LLVM_YAML_STRONG_TYPEDEF(uint16_t, SectionAlignment)
112 /// Mach-O has a 32-bit and 64-bit section record. This normalized form
113 /// can support either kind.
115 Section() : type(llvm::MachO::S_REGULAR),
116 attributes(0), alignment(1), address(0) { }
118 StringRef segmentName;
119 StringRef sectionName;
121 SectionAttr attributes;
122 SectionAlignment alignment;
124 ArrayRef<uint8_t> content;
125 Relocations relocations;
126 IndirectSymbols indirectSymbols;
130 /// A typedef so that YAML I/O can encode/decode the scope bits of an nlist.
131 LLVM_YAML_STRONG_TYPEDEF(uint8_t, SymbolScope)
133 /// A typedef so that YAML I/O can encode/decode the desc bits of an nlist.
134 LLVM_YAML_STRONG_TYPEDEF(uint16_t, SymbolDesc)
136 /// Mach-O has a 32-bit and 64-bit symbol table entry (nlist), and the symbol
137 /// type and scope and mixed in the same n_type field. This normalized form
138 /// works for any pointer size and separates out the type and scope.
140 Symbol() : type(llvm::MachO::N_UNDF), scope(0), sect(0), desc(0), value(0) { }
150 /// Check whether the given section type indicates a zero-filled section.
151 // FIXME: Utility functions of this kind should probably be moved into
153 inline bool isZeroFillSection(SectionType T) {
154 return (T == llvm::MachO::S_ZEROFILL ||
155 T == llvm::MachO::S_THREAD_LOCAL_ZEROFILL);
158 /// A typedef so that YAML I/O can (de/en)code the protection bits of a segment.
159 LLVM_YAML_STRONG_TYPEDEF(uint32_t, VMProtect)
161 /// A typedef to hold verions X.Y.X packed into 32-bit xxxx.yy.zz
162 LLVM_YAML_STRONG_TYPEDEF(uint32_t, PackedVersion)
164 /// Segments are only used in normalized final linked images (not in relocatable
165 /// object files). They specify how a range of the file is loaded.
170 VMProtect init_access;
171 VMProtect max_access;
174 /// Only used in normalized final linked images to specify on which dylibs
176 struct DependentDylib {
178 LoadCommandType kind;
179 PackedVersion compatVersion;
180 PackedVersion currentVersion;
183 /// A normalized rebasing entry. Only used in normalized final linked images.
184 struct RebaseLocation {
190 /// A normalized binding entry. Only used in normalized final linked images.
191 struct BindLocation {
197 StringRef symbolName;
201 /// A typedef so that YAML I/O can encode/decode export flags.
202 LLVM_YAML_STRONG_TYPEDEF(uint32_t, ExportFlags)
204 /// A normalized export entry. Only used in normalized final linked images.
208 ExportSymbolKind kind;
214 /// A normalized data-in-code entry.
221 /// A typedef so that YAML I/O can encode/decode mach_header.flags.
222 LLVM_YAML_STRONG_TYPEDEF(uint32_t, FileFlags)
225 struct NormalizedFile {
226 MachOLinkingContext::Arch arch = MachOLinkingContext::arch_unknown;
227 HeaderFileType fileType = llvm::MachO::MH_OBJECT;
229 std::vector<Segment> segments; // Not used in object files.
230 std::vector<Section> sections;
232 // Symbols sorted by kind.
233 std::vector<Symbol> localSymbols;
234 std::vector<Symbol> globalSymbols;
235 std::vector<Symbol> undefinedSymbols;
236 std::vector<Symbol> stabsSymbols;
238 // Maps to load commands with no LINKEDIT content (final linked images only).
239 std::vector<DependentDylib> dependentDylibs;
240 StringRef installName; // dylibs only
241 PackedVersion compatVersion = 0; // dylibs only
242 PackedVersion currentVersion = 0; // dylibs only
243 bool hasUUID = false;
244 bool hasMinVersionLoadCommand = false;
245 bool generateDataInCodeLoadCommand = false;
246 std::vector<StringRef> rpaths;
247 Hex64 entryAddress = 0;
249 MachOLinkingContext::OS os = MachOLinkingContext::OS::unknown;
250 Hex64 sourceVersion = 0;
251 PackedVersion minOSverson = 0;
252 PackedVersion sdkVersion = 0;
253 LoadCommandType minOSVersionKind = (LoadCommandType)0;
255 // Maps to load commands with LINKEDIT content (final linked images only).
257 std::vector<RebaseLocation> rebasingInfo;
258 std::vector<BindLocation> bindingInfo;
259 std::vector<BindLocation> weakBindingInfo;
260 std::vector<BindLocation> lazyBindingInfo;
261 std::vector<Export> exportInfo;
262 std::vector<uint8_t> functionStarts;
263 std::vector<DataInCode> dataInCode;
270 // For any allocations in this struct which need to be owned by this struct.
271 BumpPtrAllocator ownedAllocations;
274 /// Tests if a file is a non-fat mach-o object file.
275 bool isThinObjectFile(StringRef path, MachOLinkingContext::Arch &arch);
277 /// If the buffer is a fat file with the request arch, then this function
278 /// returns true with 'offset' and 'size' set to location of the arch slice
279 /// within the buffer. Otherwise returns false;
280 bool sliceFromFatFile(MemoryBufferRef mb, MachOLinkingContext::Arch arch,
281 uint32_t &offset, uint32_t &size);
283 /// Reads a mach-o file and produces an in-memory normalized view.
284 llvm::Expected<std::unique_ptr<NormalizedFile>>
285 readBinary(std::unique_ptr<MemoryBuffer> &mb,
286 const MachOLinkingContext::Arch arch);
288 /// Takes in-memory normalized view and writes a mach-o object file.
289 llvm::Error writeBinary(const NormalizedFile &file, StringRef path);
291 size_t headerAndLoadCommandsSize(const NormalizedFile &file);
294 /// Parses a yaml encoded mach-o file to produce an in-memory normalized view.
295 llvm::Expected<std::unique_ptr<NormalizedFile>>
296 readYaml(std::unique_ptr<MemoryBuffer> &mb);
298 /// Writes a yaml encoded mach-o files given an in-memory normalized view.
299 std::error_code writeYaml(const NormalizedFile &file, raw_ostream &out);
302 normalizedObjectToAtoms(MachOFile *file,
303 const NormalizedFile &normalizedFile,
307 normalizedDylibToAtoms(MachODylibFile *file,
308 const NormalizedFile &normalizedFile,
311 /// Takes in-memory normalized dylib or object and parses it into lld::File
312 llvm::Expected<std::unique_ptr<lld::File>>
313 normalizedToAtoms(const NormalizedFile &normalizedFile, StringRef path,
316 /// Takes atoms and generates a normalized macho-o view.
317 llvm::Expected<std::unique_ptr<NormalizedFile>>
318 normalizedFromAtoms(const lld::File &atomFile, const MachOLinkingContext &ctxt);
321 } // namespace normalized
323 /// Class for interfacing mach-o yaml files into generic yaml parsing
324 class MachOYamlIOTaggedDocumentHandler : public YamlIOTaggedDocumentHandler {
326 MachOYamlIOTaggedDocumentHandler(MachOLinkingContext::Arch arch)
328 bool handledDocTag(llvm::yaml::IO &io, const lld::File *&file) const override;
330 const MachOLinkingContext::Arch _arch;
333 } // namespace mach_o
336 #endif // LLD_READER_WRITER_MACHO_NORMALIZE_FILE_H