llvm-project/lld/lib/ReaderWriter/MachO/MachONormalizedFile.h

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9.1 KiB
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//===- lib/ReaderWriter/MachO/NormalizedFile.h ----------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file These data structures comprise the "normalized" view of
/// mach-o object files. The normalized view is an in-memory only data structure
/// which is always in native endianness and pointer size.
///
/// The normalized view easily converts to and from YAML using YAML I/O.
///
/// The normalized view converts to and from binary mach-o object files using
/// the writeBinary() and readBinary() functions.
///
/// The normalized view converts to and from lld::Atoms using the
/// normalizedToAtoms() and normalizedFromAtoms().
///
/// Overall, the conversion paths available look like:
///
/// +---------------+
/// | binary mach-o |
/// +---------------+
/// ^
/// |
/// v
/// +------------+ +------+
/// | normalized | <-> | yaml |
/// +------------+ +------+
/// ^
/// |
/// v
/// +-------+
/// | Atoms |
/// +-------+
///
#include "lld/Core/Error.h"
#include "lld/Core/LLVM.h"
#include "lld/ReaderWriter/MachOLinkingContext.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/MachO.h"
#include "llvm/Support/YAMLTraits.h"
#ifndef LLD_READER_WRITER_MACHO_NORMALIZE_FILE_H
#define LLD_READER_WRITER_MACHO_NORMALIZE_FILE_H
using llvm::BumpPtrAllocator;
using llvm::yaml::Hex64;
using llvm::yaml::Hex32;
using llvm::yaml::Hex8;
using llvm::yaml::SequenceTraits;
using llvm::MachO::HeaderFileType;
using llvm::MachO::BindType;
using llvm::MachO::RebaseType;
using llvm::MachO::NListType;
using llvm::MachO::RelocationInfoType;
using llvm::MachO::SectionType;
using llvm::MachO::LoadCommandType;
using llvm::MachO::ExportSymbolKind;
namespace lld {
namespace mach_o {
namespace normalized {
/// The real mach-o relocation record is 8-bytes on disk and is
/// encoded in one of two different bit-field patterns. This
/// normalized form has the union of all possible fields.
struct Relocation {
Relocation() : offset(0), scattered(false),
type(llvm::MachO::GENERIC_RELOC_VANILLA),
length(0), pcRel(false), isExtern(false), value(0),
symbol(0) { }
Hex32 offset;
bool scattered;
RelocationInfoType type;
uint8_t length;
bool pcRel;
bool isExtern;
Hex32 value;
uint32_t symbol;
};
/// A typedef so that YAML I/O can treat this vector as a sequence.
typedef std::vector<Relocation> Relocations;
/// A typedef so that YAML I/O can process the raw bytes in a section.
typedef std::vector<Hex8> ContentBytes;
/// A typedef so that YAML I/O can treat indirect symbols as a flow sequence.
typedef std::vector<uint32_t> IndirectSymbols;
/// A typedef so that YAML I/O can encode/decode section attributes.
LLVM_YAML_STRONG_TYPEDEF(uint32_t, SectionAttr);
/// Mach-O has a 32-bit and 64-bit section record. This normalized form
/// can support either kind.
struct Section {
Section() : type(llvm::MachO::S_REGULAR),
attributes(0), alignment(0), address(0) { }
StringRef segmentName;
StringRef sectionName;
SectionType type;
SectionAttr attributes;
uint32_t alignment;
Hex64 address;
ArrayRef<uint8_t> content;
Relocations relocations;
IndirectSymbols indirectSymbols;
};
/// A typedef so that YAML I/O can encode/decode the scope bits of an nlist.
LLVM_YAML_STRONG_TYPEDEF(uint8_t, SymbolScope);
/// A typedef so that YAML I/O can encode/decode the desc bits of an nlist.
LLVM_YAML_STRONG_TYPEDEF(uint16_t, SymbolDesc);
/// Mach-O has a 32-bit and 64-bit symbol table entry (nlist), and the symbol
/// type and scope and mixed in the same n_type field. This normalized form
/// works for any pointer size and separates out the type and scope.
struct Symbol {
Symbol() : type(llvm::MachO::N_UNDF), scope(0), sect(0), desc(0), value(0) { }
StringRef name;
NListType type;
SymbolScope scope;
uint8_t sect;
SymbolDesc desc;
Hex64 value;
};
/// A typedef so that YAML I/O can (de/en)code the protection bits of a segment.
LLVM_YAML_STRONG_TYPEDEF(uint32_t, VMProtect);
/// Segments are only used in normalized final linked images (not in relocatable
/// object files). They specify how a range of the file is loaded.
struct Segment {
StringRef name;
Hex64 address;
Hex64 size;
VMProtect access;
};
/// Only used in normalized final linked images to specify on which dylibs
/// it depends.
struct DependentDylib {
StringRef path;
LoadCommandType kind;
};
/// A normalized rebasing entry. Only used in normalized final linked images.
struct RebaseLocation {
Hex32 segOffset;
uint8_t segIndex;
RebaseType kind;
};
/// A normalized binding entry. Only used in normalized final linked images.
struct BindLocation {
Hex32 segOffset;
uint8_t segIndex;
BindType kind;
bool canBeNull;
int ordinal;
StringRef symbolName;
Hex64 addend;
};
/// A typedef so that YAML I/O can encode/decode export flags.
LLVM_YAML_STRONG_TYPEDEF(uint32_t, ExportFlags);
/// A normalized export entry. Only used in normalized final linked images.
struct Export {
StringRef name;
Hex64 offset;
ExportSymbolKind kind;
ExportFlags flags;
Hex32 otherOffset;
StringRef otherName;
};
/// A typedef so that YAML I/O can encode/decode mach_header.flags.
LLVM_YAML_STRONG_TYPEDEF(uint32_t, FileFlags);
///
struct NormalizedFile {
NormalizedFile() : arch(MachOLinkingContext::arch_unknown),
fileType(llvm::MachO::MH_OBJECT),
flags(0),
hasUUID(false),
os(MachOLinkingContext::OS::unknown) { }
MachOLinkingContext::Arch arch;
HeaderFileType fileType;
FileFlags flags;
std::vector<Segment> segments; // Not used in object files.
std::vector<Section> sections;
// Symbols sorted by kind.
std::vector<Symbol> localSymbols;
std::vector<Symbol> globalSymbols;
std::vector<Symbol> undefinedSymbols;
// Maps to load commands with no LINKEDIT content (final linked images only).
std::vector<DependentDylib> dependentDylibs;
StringRef installName;
bool hasUUID;
std::vector<StringRef> rpaths;
Hex64 entryAddress;
MachOLinkingContext::OS os;
Hex64 sourceVersion;
Hex32 minOSverson;
Hex32 sdkVersion;
// Maps to load commands with LINKEDIT content (final linked images only).
std::vector<RebaseLocation> rebasingInfo;
std::vector<BindLocation> bindingInfo;
std::vector<BindLocation> weakBindingInfo;
std::vector<BindLocation> lazyBindingInfo;
std::vector<Export> exportInfo;
// TODO:
// code-signature
// split-seg-info
// function-starts
// data-in-code
// For any allocations in this struct which need to be owned by this struct.
BumpPtrAllocator ownedAllocations;
};
/// Reads a mach-o file and produces an in-memory normalized view.
ErrorOr<std::unique_ptr<NormalizedFile>>
readBinary(std::unique_ptr<MemoryBuffer> &mb,
const MachOLinkingContext::Arch arch);
/// Takes in-memory normalized view and writes a mach-o object file.
error_code
writeBinary(const NormalizedFile &file, StringRef path);
size_t headerAndLoadCommandsSize(const NormalizedFile &file);
/// Parses a yaml encoded mach-o file to produce an in-memory normalized view.
ErrorOr<std::unique_ptr<NormalizedFile>>
readYaml(std::unique_ptr<MemoryBuffer> &mb);
/// Writes a yaml encoded mach-o files given an in-memory normalized view.
error_code
writeYaml(const NormalizedFile &file, raw_ostream &out);
/// Takes in-memory normalized dylib or object and parses it into lld::File
ErrorOr<std::unique_ptr<lld::File>>
normalizedToAtoms(const NormalizedFile &normalizedFile, StringRef path,
bool copyRefs);
/// Takes atoms and generates a normalized macho-o view.
ErrorOr<std::unique_ptr<NormalizedFile>>
normalizedFromAtoms(const lld::File &atomFile, const MachOLinkingContext &ctxt);
} // namespace normalized
/// Class for interfacing mach-o yaml files into generic yaml parsing
class MachOYamlIOTaggedDocumentHandler : public YamlIOTaggedDocumentHandler {
bool handledDocTag(llvm::yaml::IO &io, const lld::File *&file) const;
};
} // namespace mach_o
} // namespace lld
#endif // LLD_READER_WRITER_MACHO_NORMALIZE_FILE_H