1421 lines
55 KiB
C++
1421 lines
55 KiB
C++
//===- lib/ReaderWriter/ELF/WriterELF.cpp ---------------------------------===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "lld/ReaderWriter/WriterELF.h"
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#include "ReferenceKinds.h"
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#include "lld/Core/DefinedAtom.h"
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#include "lld/Core/File.h"
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#include "lld/Core/InputFiles.h"
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#include "lld/Core/Reference.h"
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#include "lld/Core/SharedLibraryAtom.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/OwningPtr.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Object/ELF.h"
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#include "llvm/Support/Allocator.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ELF.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/FileOutputBuffer.h"
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#include "llvm/Support/Format.h"
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#include "llvm/Support/MathExtras.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/system_error.h"
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#include <map>
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#include <tuple>
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#include <vector>
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#include <algorithm>
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using namespace llvm;
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using namespace llvm::object;
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namespace lld {
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namespace elf {
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// The group decides where sections of similar permissions reside
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// inside a file. This is also used to create program headers. Each group
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// will be in a new segment.
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/// \name Chunk Groups
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/// Each "Chunk" should be arranged in a weak strict order
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/// This is done to minimize memory utilization when creating program segments.
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/// This will remain in place till a more felxible mechanism of moving chunks
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/// around and packing for memory efficiency is put in place.
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/// The Chunks are arranged by group numbers. Every switch from group A to B
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/// triggers a formation of new segment. Additionally segments are also made
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/// within a group if there are vast regions (multiple pages) of 0 for
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/// alignment constraints.
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enum {
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/// @{
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///Invalid group (default on creation)
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CG_INVALID = 0x0,
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///This is a "header" kind of chunk that goes at beginning of ELF file
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CG_HEADER = 0x1,
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///This is a section chunk with read write and execute permissions
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CG_RWX = 0x3,
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///This is a section chunk with read and execute permissions
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CG_RX = 0x4,
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///This is a section chunk with read permission
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CG_R = 0x5,
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///This is a section chunk with read and write permissions
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CG_RW = 0x6,
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///This is a section chunk with write and execute permissions
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CG_WX = 0x7,
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///This is a section chunk with write permission
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CG_W = 0x8,
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///This is a section chunk with execute permission
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CG_X = 0x9,
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///This is a section which is no loaded by program loader
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CG_NO_LOAD = 0xFE,
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///This is ELF file metadata that goes at end of file
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CG_FILE_END = 0xFF
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/// @}
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};
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template<support::endianness target_endianness, bool is64Bits>
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class ELFWriter;
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/// \brief A Chunk is a contiguous range of space.
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template<support::endianness target_endianness, bool is64Bits>
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class Chunk {
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public:
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LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits)
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virtual ~Chunk() {}
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virtual StringRef segmentName() const = 0;
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virtual bool occupiesNoDiskSpace();
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virtual void write(uint8_t *fileBuffer) = 0;
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void assignFileOffset(uint64_t &curOff, uint64_t &curAddr);
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virtual const char *info() = 0;
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uint64_t size() const;
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uint64_t address() const;
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uint64_t fileOffset() const;
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uint64_t align2() const;
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static uint64_t alignTo(uint64_t value, uint8_t align2);
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uint64_t ordinal() const { return _ordinal;}
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void setOrdinal(uint64_t newVal) { _ordinal = newVal;}
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void setGroup(uint16_t val) { _group = val;}
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uint16_t group() const { return _group;}
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void init();
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bool isLoadable() { return _isLoadable; }
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void isLoadable(uint64_t val) { _isLoadable = val; }
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enum class Kind {
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Header, // This is a header chunk
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Section // chunk represents a section
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};
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Kind getChunkKind() const { return _cKind; }
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private:
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const Kind _cKind;
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protected:
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Chunk();
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Chunk(Kind K): _cKind(K) { this->init();}
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uint64_t _size;
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uint64_t _address;
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uint64_t _fileOffset;
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uint64_t _align2;
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uint64_t _ordinal;
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uint16_t _group;
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bool _isLoadable;
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};
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template<support::endianness target_endianness, bool is64Bits>
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static void swapChunkPositions(Chunk<target_endianness, is64Bits>&a,
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Chunk<target_endianness, is64Bits>&b) {
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uint64_t tempOrdinal;
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if (a.ordinal() == b.ordinal()) return;
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tempOrdinal = a.ordinal();
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a.setOrdinal(b.ordinal());
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b.setOrdinal(tempOrdinal);
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}
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template<support::endianness target_endianness, bool is64Bits>
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bool chunkGroupSort(Chunk<target_endianness, is64Bits> *A,
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Chunk<target_endianness, is64Bits> *B) {
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if (A->group() == CG_INVALID || B->group() == CG_INVALID)
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llvm_unreachable("Invalid group number");
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return A->group() < B->group();
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}
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template<support::endianness target_endianness, bool is64Bits>
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struct ChunkComparator {
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bool operator()(uint16_t A, Chunk<target_endianness, is64Bits> *B) {
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return A < B->group();
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}
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bool operator()(Chunk<target_endianness, is64Bits> *A, uint16_t B) {
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return A->group() < B;
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}
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#if defined(_ITERATOR_DEBUG_LEVEL) && _ITERATOR_DEBUG_LEVEL == 2
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bool operator()(Chunk<target_endianness, is64Bits> *A,
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Chunk<target_endianness, is64Bits> *B) {
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return A->group() < B->group();
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}
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#endif
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};
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/// Pair of atom and offset in section.
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typedef std::tuple<const DefinedAtom*, uint64_t> AtomInfo;
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/// \brief A SectionChunk represents ELF sections
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template<support::endianness target_endianness, bool is64Bits>
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class SectionChunk : public Chunk<target_endianness, is64Bits> {
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public:
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virtual StringRef segmentName() const { return _segmentName; }
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virtual bool occupiesNoDiskSpace();
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virtual const char *info();
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StringRef sectionName() { return _sectionName; }
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uint64_t shStrtableOffset(){ return _offsetInStringTable; }
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void setShStrtableOffset (uint64_t val) {
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_offsetInStringTable = val; }
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uint32_t flags() { return _flags; }
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uint32_t type() const { return _type; }
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uint64_t link() { return _link; }
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void link(uint64_t val) { _link = val; }
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uint16_t shinfo() { return _shinfo; }
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uint64_t entsize() { return _entsize; }
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SectionChunk(StringRef secName, StringRef segName, bool loadable,
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uint64_t flags , uint64_t link, uint64_t info ,
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uint64_t type, uint64_t entsz, const WriterOptionsELF &op,
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ELFWriter<target_endianness, is64Bits> &writer);
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static inline bool classof(const Chunk<target_endianness, is64Bits> *c) {
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return c->getChunkKind() == Chunk<target_endianness, is64Bits>::Kind
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::Section;
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}
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protected:
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uint64_t _link;
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uint64_t _shinfo;
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uint16_t _entsize;
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StringRef _segmentName;
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StringRef _sectionName;
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const WriterOptionsELF &_options;
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ELFWriter<target_endianness, is64Bits> &_writer;
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uint64_t _flags;
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uint64_t _type;
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uint64_t _offsetInStringTable;
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};
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template<support::endianness target_endianness, bool is64Bits>
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bool IsBss(const Chunk<target_endianness, is64Bits> *A) {
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if (auto X = llvm::dyn_cast<SectionChunk<target_endianness, is64Bits>>(A))
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return X->type() != ELF::SHT_NOBITS;
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llvm_unreachable("Call to a non section type chunk");
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// adding a non-reachable return bool for making compiler happy
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return false;
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}
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/// \brief A StockSectionChunk is a section created by linker with all
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/// attributes concluded from the defined atom contained within.
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template<support::endianness target_endianness, bool is64Bits>
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class StockSectionChunk : public SectionChunk<target_endianness, is64Bits> {
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public:
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virtual StringRef segmentName() const { return this->_segmentName; }
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void appendAtom(const DefinedAtom*);
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virtual void write(uint8_t *filebuffer);
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const ArrayRef<AtomInfo> atoms() const;
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StockSectionChunk(StringRef sectionName, bool loadable,
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DefinedAtom::ContentType type,
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const WriterOptionsELF &options,
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ELFWriter<target_endianness, is64Bits> &writer);
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private:
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std::vector<AtomInfo> _atoms;
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};
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/// \brief An ELFHeaderChunk represents the Elf[32/64]_Ehdr structure at the
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/// start of an ELF executable file.
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template<support::endianness target_endianness, bool is64Bits>
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class ELFHeaderChunk : public Chunk<target_endianness, is64Bits> {
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public:
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LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits)
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typedef object::Elf_Ehdr_Impl<target_endianness, is64Bits> Elf_Ehdr;
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ELFHeaderChunk(const WriterOptionsELF &options,
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const File &file);
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void e_ident(int I, unsigned char C) { _eh.e_ident[I] = C; }
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void e_type(uint16_t type) { _eh.e_type = type; }
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void e_machine(uint16_t machine) { _eh.e_machine = machine; }
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void e_version(uint32_t version) { _eh.e_version = version; }
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void e_entry(uint64_t entry) { _eh.e_entry = entry; }
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void e_phoff(uint64_t phoff) { _eh.e_phoff = phoff; }
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void e_shoff(uint64_t shoff) { _eh.e_shoff = shoff; }
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void e_flags(uint32_t flags) { _eh.e_flags = flags; }
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void e_ehsize(uint16_t ehsize) { _eh.e_ehsize = ehsize; }
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void e_phentsize(uint16_t phentsize) { _eh.e_phentsize = phentsize; }
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void e_phnum(uint16_t phnum) { _eh.e_phnum = phnum; }
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void e_shentsize(uint16_t shentsize) { _eh.e_shentsize = shentsize; }
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void e_shnum(uint16_t shnum) { _eh.e_shnum = shnum; }
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void e_shstrndx(uint16_t shstrndx) { _eh.e_shstrndx = shstrndx; }
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uint64_t size() { return sizeof (Elf_Ehdr); }
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virtual StringRef segmentName() const;
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virtual void write(uint8_t *fileBuffer);
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virtual const char *info();
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static inline bool classof(const Chunk<target_endianness, is64Bits> *c) {
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return c->getChunkKind() == Chunk<target_endianness, is64Bits>::Kind
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::Header;
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}
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private:
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Elf_Ehdr _eh;
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};
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/// \brief An ELFSectionHeaderChunk represents the Elf[32/64]_Shdr structure
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/// that is placed right after the ELFHeader.
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///
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template<support::endianness target_endianness, bool is64Bits>
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class ELFSectionHeaderChunk : public Chunk<target_endianness, is64Bits> {
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public:
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LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits)
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typedef object::Elf_Shdr_Impl<target_endianness, is64Bits> Elf_Shdr;
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ELFSectionHeaderChunk(const WriterOptionsELF &Options,
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ELFWriter<target_endianness, is64Bits>&);
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void createHeaders();
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virtual StringRef segmentName() const;
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virtual void write(uint8_t *filebuffer);
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virtual const char *info();
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void computeSize();
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uint16_t count();
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uint16_t size();
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void fixOffsets();
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const ArrayRef<Elf_Shdr*> sectionInfo() {
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return _sectionInfo;
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}
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static inline bool classof(const Chunk<target_endianness, is64Bits> *c) {
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return c->getChunkKind() == Chunk<target_endianness, is64Bits>::Kind
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::Header;
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}
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private:
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const WriterOptionsELF &_options;
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ELFWriter<target_endianness, is64Bits> &_writer;
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llvm::BumpPtrAllocator _sectionAllocate;
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std::vector<Elf_Shdr*> _sectionInfo;
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};
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/// \brief Represents the shstr section.
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///
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/// This is a contiguous memory that has all the symbol strings each ending with
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/// null character. We might need more than one such chunks shstrtab for setting
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/// e_shstrndx in ELHHeaderChunk and strtab for use with symtab
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template<support::endianness target_endianness, bool is64Bits>
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class ELFStringSectionChunk : public SectionChunk<target_endianness, is64Bits> {
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public:
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ELFStringSectionChunk(const WriterOptionsELF &Options,
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ELFWriter<target_endianness, is64Bits> &writer,
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StringRef secName);
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virtual StringRef segmentName() const { return this->_segmentName; }
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uint64_t addString(StringRef symName);
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const char *info();
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virtual void write(uint8_t *filebuffer);
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private:
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std::vector<StringRef> _stringSection;
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};
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/// \brief Represents the symtab section
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///
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/// ELFSymbolTableChunk represents the Symbol table as per ELF ABI
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/// This is a table with Elf[32/64]_Sym entries in it.
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template<support::endianness target_endianness, bool is64Bits>
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class ELFSymbolTableChunk : public SectionChunk<target_endianness, is64Bits> {
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public:
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typedef object::Elf_Sym_Impl<target_endianness, is64Bits> Elf_Sym;
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ELFSymbolTableChunk(const WriterOptionsELF &options,
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ELFWriter<target_endianness, is64Bits> &writer,
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StringRef secName);
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virtual StringRef segmentName() const { return this->_segmentName; }
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void addSymbol(const Atom *a, uint16_t shndx);
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void addSymbol(Elf_Sym *x);
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void fixSymbolValue();
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const char *info();
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void setAttributes();
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virtual void write(uint8_t *fileBuffer);
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private:
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std::vector<Elf_Sym*> _symbolTable;
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ELFStringSectionChunk<target_endianness, is64Bits> *_stringSection;
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llvm::BumpPtrAllocator _symbolAllocate;
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std::map<Elf_Sym*, const Atom*> _symbolToAtom;
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};
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/// \brief ELFProgramHeaderChunk represents the Elf[32/64]_Phdr structure near
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/// the start of an ELF executable file. ELFHeader's e_phentsize and e_phnum
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/// show the number of entries in table and size of each one.
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template<support::endianness target_endianness, bool is64Bits>
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class ELFProgramHeaderChunk : public Chunk<target_endianness, is64Bits> {
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public:
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LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits)
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typedef object::Elf_Phdr<target_endianness, is64Bits> Elf_Phdr;
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ELFProgramHeaderChunk(const WriterOptionsELF &options,
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ELFWriter<target_endianness, is64Bits> &);
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virtual StringRef segmentName() const;
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virtual void write(uint8_t *filebuffer);
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virtual const char *info();
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void createPHeaders();
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uint64_t computeNumber();
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static inline bool classof(const Chunk<target_endianness, is64Bits> *c) {
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return c->getChunkKind() == Chunk<target_endianness, is64Bits>::Kind
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::Header;
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}
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private:
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typedef typename std::vector<SectionChunk<target_endianness, is64Bits>*>
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::iterator secIterator;
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const WriterOptionsELF &_options;
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ELFWriter<target_endianness, is64Bits> &_writer;
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std::vector<Elf_Phdr*> _programHeaders;
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llvm::BumpPtrAllocator _headerAllocate;
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typedef std::pair<uint64_t, uint64_t> sectionRange;
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std::vector<sectionRange> _segments;
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std::map<uint16_t, uint16_t> _groupToPF;
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};
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//===----------------------------------------------------------------------===//
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// Chunk
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//===----------------------------------------------------------------------===//
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template<support::endianness target_endianness, bool is64Bits>
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Chunk<target_endianness, is64Bits>::Chunk(){
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this->init();
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}
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template<support::endianness target_endianness, bool is64Bits>
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void Chunk<target_endianness, is64Bits>::init(){
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this->_size = 0;
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this->_address = 0;
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this->_fileOffset = 0;
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this->_align2 = 0;
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this->_group = CG_INVALID;
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this->_isLoadable = false;
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// 0 and 1 are reserved. 0 for ELF header and 1 for program header.
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static uint64_t orderNumber = 0;
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_ordinal = orderNumber++;
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}
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template<support::endianness target_endianness, bool is64Bits>
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bool Chunk<target_endianness, is64Bits>::occupiesNoDiskSpace() {
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return false;
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}
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template<support::endianness target_endianness, bool is64Bits>
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uint64_t Chunk<target_endianness, is64Bits>::size() const {
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return _size;
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}
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template<support::endianness target_endianness, bool is64Bits>
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uint64_t Chunk<target_endianness, is64Bits>::align2() const {
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return _align2;
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}
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template<support::endianness target_endianness, bool is64Bits>
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uint64_t Chunk<target_endianness, is64Bits>::address() const {
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return _address;
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}
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template<support::endianness target_endianness, bool is64Bits>
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uint64_t Chunk<target_endianness, is64Bits>::fileOffset() const {
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return _fileOffset;
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}
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template<support::endianness target_endianness, bool is64Bits>
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uint64_t Chunk<target_endianness, is64Bits>::
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alignTo(uint64_t value, uint8_t align2) {
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uint64_t align = 1 << align2;
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return (value + (align - 1)) & (-align);
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}
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template<support::endianness target_endianness, bool is64Bits>
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void Chunk<target_endianness, is64Bits>::
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assignFileOffset(uint64_t &curOffset, uint64_t &curAddress) {
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if (occupiesNoDiskSpace()) {
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// FileOffset does not change, but virtual address does change.
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uint64_t alignedAddress =
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|
alignTo(curAddress, _align2 ? static_cast<uint8_t>(llvm::Log2_64(_align2))
|
|
: 0);
|
|
_address = alignedAddress;
|
|
curAddress = alignedAddress + _size;
|
|
} else {
|
|
// FileOffset and address both move by _size amount after alignment.
|
|
uint64_t alignPadding =
|
|
alignTo(curAddress, _align2 ? static_cast<uint8_t>(llvm::Log2_64(_align2))
|
|
: 0) - curAddress;
|
|
_fileOffset = curOffset + alignPadding;
|
|
_address = curAddress + alignPadding;
|
|
curOffset = _fileOffset + _size;
|
|
curAddress = _address + _size;
|
|
}
|
|
|
|
DEBUG_WITH_TYPE("WriterELF-layout", dbgs()
|
|
<< " fileOffset="
|
|
<< format("0x%08X", _fileOffset)
|
|
<< " address="
|
|
<< format("0x%016X", _address)
|
|
<< " info=" << info() << "\n");
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// SectionChunk
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
SectionChunk<target_endianness, is64Bits>::
|
|
SectionChunk(StringRef secName, StringRef segName, bool loadable,
|
|
uint64_t flags , uint64_t link, uint64_t info , uint64_t type,
|
|
uint64_t entsz, const WriterOptionsELF &op,
|
|
ELFWriter<target_endianness, is64Bits> &writer)
|
|
: Chunk<target_endianness, is64Bits>(Chunk<target_endianness, is64Bits>
|
|
::Kind::Section)
|
|
, _link(link)
|
|
, _shinfo(info)
|
|
, _entsize(entsz)
|
|
, _segmentName(segName)
|
|
, _sectionName(secName)
|
|
, _options(op)
|
|
, _writer(writer)
|
|
, _flags(flags)
|
|
, _type(type)
|
|
, _offsetInStringTable(0) {
|
|
this->isLoadable(loadable);
|
|
}
|
|
//FIXME: We need to make decision here for every section created
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
bool SectionChunk<target_endianness, is64Bits>::occupiesNoDiskSpace() {
|
|
return false;
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
const char *SectionChunk<target_endianness, is64Bits>::info() {
|
|
return _sectionName.data();
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// StockSectionChunk
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
StockSectionChunk<target_endianness, is64Bits>::
|
|
StockSectionChunk(StringRef secName, bool loadable,
|
|
DefinedAtom::ContentType type,
|
|
const WriterOptionsELF &options,
|
|
ELFWriter<target_endianness, is64Bits> &writer)
|
|
: SectionChunk<target_endianness, is64Bits>(secName, "PT_NULL",
|
|
loadable, 0lu, 0lu, 0u, 0lu, 0lu,
|
|
options, writer) {
|
|
this->_segmentName = this->_isLoadable ? "PT_LOAD" : "PT_NULL" ;
|
|
// If the section is custom loadable section, group should be set explicitly.
|
|
// Stock non loadable section go as NO_LOAD and others will get their
|
|
// group determined by the atoms contained within. Many constant
|
|
// sections will have no symbols but the constants are referred as
|
|
// offset from start symbol, hence there may not be any defined atoms being
|
|
// appended to them, we force them at time of creation to CG_R
|
|
this->setGroup(this->isLoadable() ? CG_INVALID : CG_NO_LOAD);
|
|
switch(type) {
|
|
case DefinedAtom::typeCode:
|
|
this->_type = ELF::SHT_PROGBITS;
|
|
break;
|
|
case DefinedAtom::typeData:
|
|
this->_type = ELF::SHT_PROGBITS;
|
|
break;
|
|
case DefinedAtom::typeZeroFill:
|
|
this->_type = ELF::SHT_NOBITS;
|
|
break;
|
|
case DefinedAtom::typeConstant:
|
|
this->_type = ELF::SHT_PROGBITS;
|
|
this->_flags = ELF::SHF_ALLOC;
|
|
this->setGroup(CG_R);
|
|
break;
|
|
default:
|
|
llvm_unreachable("Unhandled content type for section!");
|
|
}
|
|
}
|
|
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
const ArrayRef<AtomInfo> StockSectionChunk<target_endianness, is64Bits>::
|
|
atoms() const {
|
|
return _atoms;
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void StockSectionChunk<target_endianness, is64Bits>::
|
|
appendAtom(const DefinedAtom *atom) {
|
|
static uint16_t groupArray[] = {CG_INVALID, CG_W, CG_R, CG_RW, CG_X,
|
|
CG_WX, CG_RX, CG_RWX};
|
|
// Figure out offset for atom in this section given alignment constraints.
|
|
uint64_t offset = this->_size;
|
|
DefinedAtom::Alignment atomAlign = atom->alignment();
|
|
uint64_t align2 = 1 << atomAlign.powerOf2;
|
|
uint64_t requiredModulus = atomAlign.modulus;
|
|
uint64_t currentModulus = (offset % align2);
|
|
if (currentModulus != requiredModulus) {
|
|
if (requiredModulus > currentModulus)
|
|
offset += requiredModulus - currentModulus;
|
|
else
|
|
offset += align2 + requiredModulus - currentModulus;
|
|
}
|
|
// Record max alignment of any atom in this section.
|
|
if (align2 > this->_align2)
|
|
this->_align2 = align2;
|
|
// Assign atom to this section with this offset.
|
|
_atoms.emplace_back(atom, offset);
|
|
// Update section size to include this atom.
|
|
this->_size = offset + atom->size();
|
|
// Update permissions
|
|
DefinedAtom::ContentPermissions perms = atom->permissions();
|
|
|
|
if ((perms & DefinedAtom::permR__) == DefinedAtom::permR__)
|
|
this->_flags |= ELF::SHF_ALLOC;
|
|
if ((perms & DefinedAtom::permRW_) == DefinedAtom::permRW_)
|
|
this->_flags |= (ELF::SHF_ALLOC | ELF::SHF_WRITE);
|
|
if ((perms & DefinedAtom::permR_X) == DefinedAtom::permR_X)
|
|
this->_flags |= (ELF::SHF_ALLOC | ELF::SHF_EXECINSTR);
|
|
if (atom->contentType() == DefinedAtom::typeZeroFill)
|
|
this->_flags |= (ELF::SHF_ALLOC | ELF::SHF_WRITE);
|
|
this->setGroup(groupArray[this->_flags]);
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void StockSectionChunk<target_endianness, is64Bits>
|
|
::write(uint8_t *chunkBuffer) {
|
|
// Each section's content is just its atoms' content.
|
|
for (const auto &ai : _atoms ) {
|
|
// Copy raw content of atom to file buffer.
|
|
ArrayRef<uint8_t> content = std::get<0>(ai)->rawContent();
|
|
uint64_t contentSize = content.size();
|
|
if (contentSize == 0)
|
|
continue;
|
|
uint8_t *atomContent = chunkBuffer + std::get<1>(ai);
|
|
std::copy_n(content.data(), contentSize, atomContent);
|
|
|
|
for (const Reference *ref : *std::get<0>(ai)){
|
|
uint32_t offset = ref->offsetInAtom();
|
|
uint64_t targetAddress = 0;
|
|
|
|
if ( ref->target() != nullptr )
|
|
targetAddress = this->_writer.addressOfAtom(ref->target());
|
|
|
|
uint64_t fixupAddress = this->_writer.addressOfAtom(std::get<0>(ai)) +
|
|
offset;
|
|
this->_writer.kindHandler()->applyFixup(ref->kind(), ref->addend(),
|
|
&atomContent[offset],
|
|
fixupAddress,
|
|
targetAddress);
|
|
}
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ELFStringSectionChunk
|
|
//===----------------------------------------------------------------------===//
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
ELFStringSectionChunk<target_endianness, is64Bits>::
|
|
ELFStringSectionChunk(const WriterOptionsELF &options,
|
|
ELFWriter<target_endianness, is64Bits> &writer,
|
|
StringRef secName)
|
|
: SectionChunk<target_endianness, is64Bits>(secName, "PT_NULL",
|
|
false, 0lu, 0lu, 0lu,
|
|
ELF::SHT_STRTAB, 0lu, options,
|
|
writer) {
|
|
// First Add a null character. It also occupies 1 byte
|
|
_stringSection.emplace_back("");
|
|
this->_size = 1;
|
|
this->setGroup(CG_NO_LOAD);
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
uint64_t ELFStringSectionChunk<target_endianness, is64Bits>::
|
|
addString(StringRef symName) {
|
|
_stringSection.emplace_back(symName);
|
|
uint64_t offset = this->_size;
|
|
this->_size += symName.size() + 1;
|
|
|
|
return offset;
|
|
}
|
|
|
|
// We need to unwrap the _stringSection and then make one large memory
|
|
// chunk of null terminated strings
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFStringSectionChunk<target_endianness, is64Bits>::
|
|
write(uint8_t *chunkBuffer) {
|
|
uint64_t chunkOffset = 0;
|
|
|
|
for (auto it : _stringSection) {
|
|
::memcpy(chunkBuffer + chunkOffset, it.data(), it.size());
|
|
chunkOffset += it.size();
|
|
::memcpy(chunkBuffer + chunkOffset, "", 1);
|
|
chunkOffset += 1;
|
|
}
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
const char *ELFStringSectionChunk<target_endianness, is64Bits>::info() {
|
|
return "String Table";
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ELFSymbolTableChunk
|
|
//===----------------------------------------------------------------------===//
|
|
template< support::endianness target_endianness, bool is64Bits>
|
|
ELFSymbolTableChunk<target_endianness, is64Bits>::ELFSymbolTableChunk
|
|
(const WriterOptionsELF &options,
|
|
ELFWriter<target_endianness, is64Bits> &writer,
|
|
StringRef secName)
|
|
: SectionChunk<target_endianness, is64Bits>(secName, StringRef("PT_NULL"),
|
|
false, 0, 0, 0, ELF::SHT_SYMTAB,
|
|
sizeof(Elf_Sym), options, writer)
|
|
{
|
|
_stringSection = this->_writer.strtab();
|
|
Elf_Sym *symbol = new (_symbolAllocate.Allocate<Elf_Sym>()) Elf_Sym;
|
|
memset ((void *)symbol,0, sizeof(Elf_Sym));
|
|
_symbolTable.push_back(symbol);
|
|
this->_link = 0;
|
|
this->_entsize = sizeof(Elf_Sym);
|
|
this->_size = sizeof(Elf_Sym);
|
|
this->_align2 = this->_options.pointerWidth();
|
|
this->setGroup(CG_NO_LOAD);
|
|
}
|
|
|
|
template< support::endianness target_endianness, bool is64Bits>
|
|
void ELFSymbolTableChunk<target_endianness, is64Bits>::fixSymbolValue(){
|
|
for (auto sym : _symbolTable) {
|
|
if ( sym->st_shndx != ELF::SHN_ABS) {
|
|
sym->st_value = this->_writer.addressOfAtom(_symbolToAtom[sym]);
|
|
}
|
|
}
|
|
}
|
|
|
|
template< support::endianness target_endianness, bool is64Bits>
|
|
void ELFSymbolTableChunk<target_endianness, is64Bits>::addSymbol(Elf_Sym *sym){
|
|
_symbolTable.push_back(sym);
|
|
this->_size+= sizeof(Elf_Sym) ;
|
|
}
|
|
|
|
/// \brief Add symbols to symbol table
|
|
/// We examine each property of atom to infer the various st_* fields in Elf*_Sym
|
|
template< support::endianness target_endianness, bool is64Bits>
|
|
void ELFSymbolTableChunk<target_endianness, is64Bits>
|
|
::addSymbol(const Atom *a, uint16_t shndx) {
|
|
Elf_Sym *symbol = new(_symbolAllocate.Allocate<Elf_Sym>()) Elf_Sym;
|
|
unsigned char b = 0, t = 0;
|
|
symbol->st_name = _stringSection->addString(a->name());
|
|
_symbolToAtom[symbol] = a;
|
|
// In relocatable files, st_value holds a section offset for a defined symbol.
|
|
// st_value is an offset from the beginning of the section that st_shndx
|
|
// identifies. After we assign file offsets we can set this value correctly.
|
|
symbol->st_size = 0;
|
|
symbol->st_shndx = shndx;
|
|
symbol->st_value = 0;
|
|
// FIXME: Need to change and account all STV* when visibilities are supported
|
|
symbol->st_other = ELF::STV_DEFAULT;
|
|
if (const DefinedAtom *da = llvm::dyn_cast<const DefinedAtom>(a)){
|
|
symbol->st_size = da->size();
|
|
lld::DefinedAtom::ContentType ct;
|
|
switch (ct = da->contentType()){
|
|
case DefinedAtom::typeCode:
|
|
t = ELF::STT_FUNC;
|
|
break;
|
|
case DefinedAtom::typeData:
|
|
t = ELF::STT_OBJECT;
|
|
break;
|
|
case DefinedAtom::typeZeroFill:
|
|
// In relocatable files, st_value holds alignment constraints for a symbol whose
|
|
// section index is SHN_COMMON
|
|
if (this->_options.type() == ELF::ET_REL){
|
|
t = ELF::STT_COMMON;
|
|
symbol->st_value = 1 << (da->alignment()).powerOf2;
|
|
symbol->st_shndx = ELF::SHN_COMMON;
|
|
}
|
|
break;
|
|
case DefinedAtom::typeFirstInSection:
|
|
t = ELF::STT_SECTION;
|
|
break;
|
|
// TODO:: How to find STT_FILE symbols?
|
|
default:
|
|
t = ELF::STT_NOTYPE;
|
|
}
|
|
|
|
if (da->scope() == DefinedAtom::scopeTranslationUnit)
|
|
b = ELF::STB_LOCAL;
|
|
else if (da->merge() == DefinedAtom::mergeAsWeak)
|
|
b = ELF::STB_WEAK;
|
|
else
|
|
b = ELF::STB_GLOBAL;
|
|
} else if (const AbsoluteAtom *aa = llvm::dyn_cast<const AbsoluteAtom>(a)){
|
|
//FIXME: Absolute atoms need more properties to differentiate each other
|
|
// based on binding and type of symbol
|
|
t = ELF::STT_OBJECT;
|
|
|
|
switch (aa->scope()) {
|
|
case AbsoluteAtom::scopeLinkageUnit:
|
|
symbol->st_other = ELF::STV_HIDDEN;
|
|
b = ELF::STB_LOCAL;
|
|
break;
|
|
case AbsoluteAtom::scopeTranslationUnit:
|
|
b = ELF::STB_LOCAL;
|
|
break;
|
|
case AbsoluteAtom::scopeGlobal:
|
|
b = ELF::STB_GLOBAL;
|
|
break;
|
|
}
|
|
symbol->st_value = aa->value();
|
|
} else {
|
|
symbol->st_value = 0;
|
|
t = ELF::STT_NOTYPE;
|
|
b = ELF::STB_LOCAL;
|
|
}
|
|
symbol->setBindingAndType(b, t);
|
|
|
|
_symbolTable.push_back(symbol);
|
|
this->_size += sizeof(Elf_Sym);
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFSymbolTableChunk<target_endianness, is64Bits>::setAttributes() {
|
|
// sh_info should be one greater than last symbol with STB_LOCAL binding
|
|
// we sort the symbol table to keep all local symbols at the beginning
|
|
std::stable_sort(_symbolTable.begin(), _symbolTable.end(), ([]
|
|
(const Elf_Sym *A, const Elf_Sym *B) -> bool {
|
|
return (A->getBinding() < B->getBinding());}));
|
|
uint16_t shInfo = 0;
|
|
for (auto i : _symbolTable) {
|
|
if (i->getBinding() != ELF::STB_LOCAL)
|
|
break;
|
|
shInfo++;
|
|
}
|
|
this->_shinfo = shInfo;
|
|
// we set the associated string table index in th sh_link member
|
|
this->_link = this->_writer.strtab()->ordinal() - 1;
|
|
this->_align2 = this->_options.pointerWidth();
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
const char *ELFSymbolTableChunk<target_endianness, is64Bits>::info() {
|
|
return "Symbol Table";
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFSymbolTableChunk<target_endianness, is64Bits>::
|
|
write(uint8_t *chunkBuffer) {
|
|
uint64_t chunkOffset = 0;
|
|
for (auto it : _symbolTable) {
|
|
::memcpy(chunkBuffer + chunkOffset, it, this->_entsize);
|
|
chunkOffset += this->_entsize;
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ELFHeaderChunk
|
|
//===----------------------------------------------------------------------===//
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
ELFHeaderChunk<target_endianness, is64Bits>
|
|
::ELFHeaderChunk(const WriterOptionsELF &options,
|
|
const File &File)
|
|
: Chunk<target_endianness, is64Bits>(Chunk<target_endianness, is64Bits>
|
|
::Kind::Header){
|
|
this->_size = size();
|
|
e_ident(ELF::EI_MAG0, 0x7f);
|
|
e_ident(ELF::EI_MAG1, 'E');
|
|
e_ident(ELF::EI_MAG2, 'L');
|
|
e_ident(ELF::EI_MAG3, 'F');
|
|
e_ident(ELF::EI_CLASS, (options.is64Bit() ? ELF::ELFCLASS64
|
|
: ELF::ELFCLASS32));
|
|
e_ident(ELF::EI_DATA, (options.endianness() == llvm::support::big)
|
|
? ELF::ELFDATA2MSB
|
|
: ELF::ELFDATA2LSB);
|
|
e_ident(ELF::EI_VERSION, 1);
|
|
e_ident(ELF::EI_OSABI, ELF::ELFOSABI_NONE);
|
|
|
|
e_type(options.type());
|
|
e_machine(options.machine());
|
|
e_version(1);
|
|
|
|
e_entry(0ULL);
|
|
e_phoff(0);
|
|
e_shoff(0ULL);
|
|
|
|
e_flags(0);
|
|
e_ehsize(this->_size);
|
|
e_phentsize(0);
|
|
e_phnum(0);
|
|
e_shentsize(0);
|
|
e_shnum(0);
|
|
e_shstrndx(0);
|
|
this->setGroup(CG_HEADER);
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
StringRef ELFHeaderChunk<target_endianness, is64Bits>
|
|
::segmentName() const {
|
|
return "ELF";
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFHeaderChunk<target_endianness, is64Bits>
|
|
::write(uint8_t *chunkBuffer) {
|
|
::memcpy(chunkBuffer, &_eh, size());
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
const char *ELFHeaderChunk<target_endianness, is64Bits>::info() {
|
|
return "elf_header";
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ELFSectionHeaderChunk
|
|
// List of Section Headers:
|
|
//[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
|
|
//[ 0] NULL 00000000 000000 000000 00 0 0 0
|
|
//[ 1] .text PROGBITS 00000000 000034 000040 00 AX 0 0 4
|
|
//===----------------------------------------------------------------------===//
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
ELFSectionHeaderChunk<target_endianness, is64Bits>
|
|
::ELFSectionHeaderChunk(const WriterOptionsELF& options,
|
|
ELFWriter<target_endianness,
|
|
is64Bits> &writer)
|
|
: Chunk<target_endianness, is64Bits>(Chunk<target_endianness, is64Bits>
|
|
::Kind::Header)
|
|
, _options(options)
|
|
, _writer(writer) {
|
|
this->_size = 0;
|
|
this->_align2 = 0;
|
|
// The first element in the list is always NULL
|
|
Elf_Shdr *nullshdr = new (_sectionAllocate.Allocate<Elf_Shdr>()) Elf_Shdr;
|
|
::memset(nullshdr, 0, sizeof (Elf_Shdr));
|
|
_sectionInfo.push_back(nullshdr);
|
|
this->_size += sizeof (Elf_Shdr);
|
|
this->setGroup(CG_FILE_END);
|
|
}
|
|
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFSectionHeaderChunk<target_endianness, is64Bits>::computeSize(){
|
|
this->_size = (this->_writer.sectionChunks().size() + 1) * sizeof(Elf_Shdr);
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFSectionHeaderChunk<target_endianness, is64Bits>::fixOffsets(){
|
|
auto it = _sectionInfo.begin();
|
|
auto sections = _writer.sectionChunks();
|
|
// First section is a NULL section with no sh_offset fix
|
|
(*it)->sh_offset = 0;
|
|
(*it)->sh_addr = 0;
|
|
++it;
|
|
for (auto &chunk : sections){
|
|
(*it)->sh_offset = chunk->fileOffset();
|
|
(*it)->sh_addr = chunk->address();
|
|
++it;
|
|
}
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFSectionHeaderChunk<target_endianness, is64Bits>::createHeaders(){
|
|
ELFStringSectionChunk<target_endianness, is64Bits> *str = _writer.shstrtab();
|
|
|
|
for (const auto &chunk : _writer.sectionChunks()) {
|
|
Elf_Shdr *shdr = new (_sectionAllocate.Allocate<Elf_Shdr>()) Elf_Shdr;
|
|
StringRef Name = chunk->sectionName();
|
|
if (chunk->shStrtableOffset() == 0){
|
|
chunk->setShStrtableOffset(str->addString(Name));
|
|
}
|
|
shdr->sh_name = chunk->shStrtableOffset();
|
|
|
|
shdr->sh_type = chunk->type();
|
|
shdr->sh_flags = chunk->flags();
|
|
// TODO: At the time of creation of this section header, we will not have
|
|
// any address and offset info. We revisit this after assigning the file
|
|
// offsets.
|
|
shdr->sh_offset = chunk->fileOffset();
|
|
shdr->sh_addr = chunk->address();
|
|
shdr->sh_size = chunk->size();
|
|
shdr->sh_link = chunk->link() ;
|
|
shdr->sh_info = chunk->shinfo();
|
|
shdr->sh_addralign = chunk->align2();
|
|
shdr->sh_entsize = chunk->entsize();
|
|
|
|
_sectionInfo.push_back(shdr);
|
|
this->_size += sizeof (Elf_Shdr);
|
|
_writer.symtab()->setAttributes();
|
|
}
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
StringRef ELFSectionHeaderChunk<target_endianness, is64Bits>
|
|
::segmentName() const {
|
|
return "PT_NULL";
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFSectionHeaderChunk<target_endianness, is64Bits>
|
|
::write(uint8_t *chunkBuffer) {
|
|
for (const auto si : _sectionInfo) {
|
|
::memcpy(chunkBuffer, si, sizeof(*si));
|
|
chunkBuffer += sizeof (*si);
|
|
}
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
uint16_t ELFSectionHeaderChunk<target_endianness, is64Bits>::count() {
|
|
return _sectionInfo.size();
|
|
}
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
uint16_t ELFSectionHeaderChunk<target_endianness, is64Bits>::size() {
|
|
return sizeof (Elf_Shdr);
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
const char *ELFSectionHeaderChunk<target_endianness, is64Bits>::info() {
|
|
return "elf_section_header";
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ELFProgramHeaderChunk
|
|
//===----------------------------------------------------------------------===//
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
ELFProgramHeaderChunk<target_endianness, is64Bits>
|
|
::ELFProgramHeaderChunk(const WriterOptionsELF &options,
|
|
ELFWriter<target_endianness, is64Bits>
|
|
&writer)
|
|
: Chunk<target_endianness, is64Bits>(Chunk<target_endianness, is64Bits>
|
|
::Kind::Header)
|
|
, _options(options)
|
|
, _writer(writer) {
|
|
this->_align2 = 0;
|
|
this->setGroup(CG_HEADER);
|
|
_groupToPF[CG_RWX] = ELF::PF_R | ELF::PF_W | ELF::PF_X;
|
|
_groupToPF[CG_RW] = ELF::PF_R | ELF::PF_W;
|
|
_groupToPF[CG_RX] = ELF::PF_R | ELF::PF_X;
|
|
_groupToPF[CG_R] = ELF::PF_R;
|
|
_groupToPF[CG_W] = ELF::PF_W;
|
|
_groupToPF[CG_WX] = ELF::PF_W | ELF::PF_X;
|
|
_groupToPF[CG_X] = ELF::PF_X;
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFProgramHeaderChunk<target_endianness, is64Bits>::createPHeaders() {
|
|
|
|
//TODO Once dynamic linking is supported, implement PHDR segment
|
|
// Implement mechanism inside this class to correctly find
|
|
// attributes for sections such as eh_frame, note etc
|
|
// when they are supported.
|
|
const uint16_t seg[] = { CG_RWX, CG_RX, CG_R, CG_RW, CG_WX, CG_W, CG_X };
|
|
std::pair<secIterator, secIterator> sectionPair;
|
|
auto sections = _writer.sectionChunks();
|
|
_programHeaders.clear();
|
|
this->_size = 0;
|
|
for (auto group : seg) {
|
|
uint64_t size = 0, mSize = 0;
|
|
sectionPair = std::equal_range(sections.begin(), sections.end(),
|
|
group, ChunkComparator<target_endianness,
|
|
is64Bits>());
|
|
if (sectionPair.first != sectionPair.second) {
|
|
// FIXME: fix occupiesNoDiskSpace() function in Chunks class
|
|
auto segBegin = sectionPair.first, segEnd = segBegin + 1;
|
|
// Since this group has a section, atleast this is a part of segment
|
|
size = (*segBegin)->occupiesNoDiskSpace() ? 0 : (*segBegin)->size();
|
|
mSize = (*segBegin)->size();
|
|
|
|
for (; segEnd != sectionPair.second; segEnd++) {
|
|
// This means there are more than 1 sections of same permissions
|
|
if ((*segEnd)->fileOffset() - (*segBegin)->fileOffset() - size >
|
|
_options.pageSize()) {
|
|
// we have a case where padding zeros span more than a page
|
|
// we can skip those pages.
|
|
Elf_Phdr *phdr = new(_headerAllocate.Allocate<Elf_Phdr>()) Elf_Phdr;
|
|
phdr->p_type = ELF::PT_LOAD;
|
|
phdr->p_offset = (*segBegin)->fileOffset();
|
|
phdr->p_vaddr = (*segBegin)->address();
|
|
phdr->p_paddr = phdr->p_vaddr;
|
|
phdr->p_filesz = size;
|
|
// memory size may be more than file size if there are sections
|
|
// that do not occupy space on disk such as .bss
|
|
phdr->p_memsz = mSize;
|
|
phdr->p_flags = _groupToPF[group];
|
|
phdr->p_align = _options.pageSize();
|
|
_programHeaders.push_back(phdr);
|
|
this->_size += sizeof(Elf_Phdr);
|
|
segBegin = segEnd;
|
|
size = (*segBegin)->occupiesNoDiskSpace() ? 0 : (*segBegin)->size();
|
|
mSize = (*segBegin)->size();
|
|
} else {
|
|
size = (*segEnd)->fileOffset() - (*segBegin)->fileOffset() +
|
|
((*segEnd)->occupiesNoDiskSpace() ? 0 : (*segEnd)->size()) ;
|
|
mSize = (*segEnd)->fileOffset() - (*segBegin)->fileOffset() +
|
|
(*segEnd)->size();
|
|
}
|
|
}
|
|
|
|
Elf_Phdr *phdr = new(_headerAllocate.Allocate<Elf_Phdr>()) Elf_Phdr;
|
|
phdr->p_type = ELF::PT_LOAD;
|
|
phdr->p_offset = (*segBegin)->fileOffset();
|
|
phdr->p_vaddr = (*segBegin)->address();
|
|
phdr->p_paddr = phdr->p_vaddr;
|
|
phdr->p_filesz = size;
|
|
phdr->p_memsz = mSize;
|
|
phdr->p_flags = _groupToPF[group];
|
|
phdr->p_align = _options.pageSize();
|
|
_programHeaders.push_back(phdr);
|
|
this->_size += sizeof(Elf_Phdr);
|
|
}
|
|
}
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
uint64_t ELFProgramHeaderChunk<target_endianness, is64Bits>::computeNumber() {
|
|
return _programHeaders.size();
|
|
}
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
const char *ELFProgramHeaderChunk<target_endianness, is64Bits>::info() {
|
|
return "elf_program_header";
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFProgramHeaderChunk<target_endianness, is64Bits>
|
|
::write(uint8_t *chunkBuffer) {
|
|
for (const auto si : _programHeaders) {
|
|
::memcpy(chunkBuffer, si, sizeof(*si));
|
|
chunkBuffer += sizeof (*si);
|
|
}
|
|
}
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
StringRef ELFProgramHeaderChunk<target_endianness, is64Bits>
|
|
::segmentName() const {
|
|
return "PT_NULL";
|
|
}
|
|
//===----------------------------------------------------------------------===//
|
|
// ELFWriter Class
|
|
//===----------------------------------------------------------------------===//
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
class ELFWriter : public Writer {
|
|
public:
|
|
LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits)
|
|
typedef object::Elf_Shdr_Impl<target_endianness, is64Bits> Elf_Shdr;
|
|
typedef object::Elf_Sym_Impl<target_endianness, is64Bits> Elf_Sym;
|
|
typedef object::Elf_Phdr<target_endianness, is64Bits> Elf_Phdr;
|
|
ELFWriter(const WriterOptionsELF &options);
|
|
virtual error_code writeFile(const lld::File &File, StringRef path);
|
|
uint64_t addressOfAtom(const Atom *atom);
|
|
|
|
std::vector<Chunk<target_endianness, is64Bits>*> chunks() const {
|
|
return _chunks; }
|
|
|
|
KindHandler *kindHandler() { return _referenceKindHandler.get(); }
|
|
|
|
std::vector<SectionChunk<target_endianness, is64Bits>*> sectionChunks() const {
|
|
return _sectionChunks ;
|
|
}
|
|
|
|
ELFStringSectionChunk<target_endianness, is64Bits> *shstrtab() const {
|
|
return _shstrtable;
|
|
}
|
|
|
|
ELFStringSectionChunk<target_endianness, is64Bits> *strtab() const {
|
|
return _strtable;
|
|
}
|
|
ELFSymbolTableChunk<target_endianness, is64Bits> *symtab() const {
|
|
return _symtable;
|
|
}
|
|
|
|
private:
|
|
void build(const lld::File &file);
|
|
void createChunks(const lld::File &file);
|
|
void buildAtomToAddressMap();
|
|
void assignFileOffsets();
|
|
const WriterOptionsELF &_options;
|
|
|
|
/// \brief AtomToAddress: Is a mapping from an Atom to the address where
|
|
/// it will live in the output file.
|
|
typedef llvm::DenseMap<const Atom*, uint64_t> AtomToAddress;
|
|
typedef typename std::vector<Chunk<target_endianness, is64Bits>*>
|
|
::iterator chunkIterator;
|
|
ELFProgramHeaderChunk<target_endianness, is64Bits> *_phdr;
|
|
ELFHeaderChunk<target_endianness, is64Bits> *ehc;
|
|
ELFStringSectionChunk<target_endianness, is64Bits> *_shstrtable ;
|
|
ELFStringSectionChunk<target_endianness, is64Bits> *_strtable ;
|
|
ELFSymbolTableChunk<target_endianness, is64Bits> *_symtable;
|
|
std::unique_ptr<KindHandler> _referenceKindHandler;
|
|
ELFSectionHeaderChunk<target_endianness, is64Bits> *_sectionHeaderChunk;
|
|
AtomToAddress _atomToAddress;
|
|
std::vector<Chunk<target_endianness, is64Bits>*> _chunks;
|
|
const DefinedAtom *_entryAtom;
|
|
std::vector<SectionChunk<target_endianness, is64Bits>*> _sectionChunks;
|
|
std::vector<StockSectionChunk<target_endianness, is64Bits>*>
|
|
_stockSectionChunks;
|
|
llvm::BumpPtrAllocator _chunkAllocate;
|
|
};
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ELFWriter
|
|
//===----------------------------------------------------------------------===//
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
ELFWriter<target_endianness, is64Bits>
|
|
::ELFWriter(const WriterOptionsELF &options)
|
|
: _options(options)
|
|
, _referenceKindHandler(KindHandler::makeHandler(_options.machine(),
|
|
target_endianness))
|
|
{}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFWriter<target_endianness, is64Bits>::build(const lld::File &file){
|
|
// Create objects for each chunk.
|
|
createChunks(file);
|
|
assignFileOffsets();
|
|
_phdr->createPHeaders();
|
|
_sectionHeaderChunk->createHeaders();
|
|
// Creating program headers changed its size. so we need to re-assign offsets
|
|
assignFileOffsets();
|
|
_sectionHeaderChunk->fixOffsets();
|
|
_phdr->createPHeaders();
|
|
buildAtomToAddressMap();
|
|
_symtable->fixSymbolValue();
|
|
ehc->e_shentsize(_sectionHeaderChunk->size());
|
|
ehc->e_shnum(_sectionHeaderChunk->count());
|
|
// We need to put the index of section string table in ELF header
|
|
// first two chunks are not sections so we subtract 2 to start sections
|
|
// and add 1 since we have a NULL header
|
|
ehc->e_shstrndx(_shstrtable->ordinal() - 1);
|
|
ehc->e_phnum(_phdr->computeNumber());
|
|
ehc->e_phoff(_phdr->fileOffset());
|
|
ehc->e_phentsize(sizeof(Elf_Phdr));
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFWriter<target_endianness, is64Bits>
|
|
::createChunks (const lld::File &file) {
|
|
std::map<StringRef, StockSectionChunk<target_endianness, is64Bits>*>
|
|
sectionMap;
|
|
|
|
// Make header chunk
|
|
ehc = new (_chunkAllocate.Allocate
|
|
<ELFHeaderChunk<target_endianness, is64Bits>>())
|
|
ELFHeaderChunk<target_endianness, is64Bits>(_options, file);
|
|
_chunks.push_back(ehc);
|
|
|
|
_phdr = new (_chunkAllocate.Allocate
|
|
<ELFProgramHeaderChunk<target_endianness, is64Bits>>())
|
|
ELFProgramHeaderChunk<target_endianness, is64Bits>(_options,
|
|
*this);
|
|
_chunks.push_back(_phdr);
|
|
|
|
// We need to create hand crafted sections such as shstrtab strtab hash and
|
|
// symtab to put relevant information in ELF structures and then process the
|
|
// atoms.
|
|
|
|
_shstrtable = new (_chunkAllocate.Allocate
|
|
<ELFStringSectionChunk<target_endianness, is64Bits>>())
|
|
ELFStringSectionChunk<target_endianness, is64Bits>
|
|
(_options, *this, ".shstrtab");
|
|
_shstrtable->setShStrtableOffset(_shstrtable->addString(".shstrtab"));
|
|
_sectionChunks.push_back(_shstrtable);
|
|
|
|
_strtable = new (_chunkAllocate.Allocate
|
|
<ELFStringSectionChunk<target_endianness, is64Bits>>())
|
|
ELFStringSectionChunk<target_endianness, is64Bits>
|
|
(_options, *this, ".strtab");
|
|
_strtable->setShStrtableOffset( _shstrtable->addString(".strtab"));
|
|
_sectionChunks.push_back(_strtable);
|
|
|
|
_symtable = new (_chunkAllocate.Allocate
|
|
<ELFSymbolTableChunk<target_endianness, is64Bits>>())
|
|
ELFSymbolTableChunk<target_endianness, is64Bits>
|
|
(_options, *this, ".symtab");
|
|
_symtable->setShStrtableOffset( _shstrtable->addString(".symtab"));
|
|
_sectionChunks.push_back(_symtable);
|
|
|
|
//TODO: implement .hash section
|
|
|
|
for (const DefinedAtom *a : file.defined() ) {
|
|
StringRef sectionName = a->customSectionName();
|
|
if (a->sectionChoice() ==
|
|
DefinedAtom::SectionChoice::sectionBasedOnContent) {
|
|
if (a->contentType() == DefinedAtom::typeZeroFill)
|
|
sectionName = ".bss";
|
|
}
|
|
auto pos = sectionMap.find(sectionName);
|
|
DefinedAtom::ContentType type = a->contentType();
|
|
if (type != DefinedAtom::typeUnknown){
|
|
if (pos == sectionMap.end()) {
|
|
StockSectionChunk<target_endianness, is64Bits>
|
|
*chunk = new(_chunkAllocate.Allocate
|
|
<StockSectionChunk<target_endianness, is64Bits>>
|
|
())StockSectionChunk<target_endianness, is64Bits>
|
|
(sectionName, true, type, _options, *this);
|
|
|
|
sectionMap[sectionName] = chunk;
|
|
chunk->appendAtom(a);
|
|
_sectionChunks.push_back(chunk);
|
|
_stockSectionChunks.push_back(chunk);
|
|
|
|
} else {
|
|
pos->second->appendAtom(a);
|
|
}
|
|
}
|
|
}
|
|
|
|
for (auto chnk : _sectionChunks)
|
|
_chunks.push_back(chnk);
|
|
|
|
_sectionHeaderChunk = new (_chunkAllocate.Allocate<ELFSectionHeaderChunk
|
|
<target_endianness, is64Bits>>())
|
|
ELFSectionHeaderChunk
|
|
<target_endianness, is64Bits>(_options, *this);
|
|
_chunks.push_back(_sectionHeaderChunk);
|
|
// We sort the chunks based on the group they belong to
|
|
std::stable_sort(_chunks.begin(), _chunks.end(),
|
|
chunkGroupSort<target_endianness, is64Bits>);
|
|
|
|
// The CG_RW group also has to be arranged such that all
|
|
// SHT_NOBITS type of sections (.*bss) are at end of this
|
|
// "partition" of group.
|
|
chunkIterator cI;
|
|
std::pair<chunkIterator, chunkIterator> range;
|
|
range = std::equal_range(_chunks.begin() + 2, _chunks.end() - 1, CG_RW,
|
|
ChunkComparator<target_endianness, is64Bits>());
|
|
|
|
cI = std::stable_partition(range.first, range.second,
|
|
IsBss<target_endianness, is64Bits>);
|
|
|
|
// We reassign all the ordinals since its needed when making headers and
|
|
// populating symbol table.
|
|
uint64_t i = 0;
|
|
for (auto chnk : _chunks) {
|
|
chnk->setOrdinal(i++);
|
|
}
|
|
|
|
// We sort the sections as per new ordinal set after group sorting.
|
|
std::stable_sort(_sectionChunks.begin(), _sectionChunks.end(),([]
|
|
(const SectionChunk<target_endianness, is64Bits> *A,
|
|
const SectionChunk<target_endianness, is64Bits> *B) -> bool {
|
|
return A->ordinal() < B->ordinal();}));
|
|
|
|
// Populate symbol table with correct st_shndx member.
|
|
if (_options.type() == ELF::ET_REL) {
|
|
for (auto chnk : _sectionChunks ) {
|
|
Elf_Sym *sym = new (_chunkAllocate.Allocate<Elf_Sym>()) Elf_Sym;
|
|
sym->st_name = 0;
|
|
sym->st_value = 0;
|
|
sym->st_size = 0;
|
|
sym->st_other = ELF::STV_DEFAULT;
|
|
// first two chunks are not sections hence we subtract 2 but there is a
|
|
// NULL section in section table so add 1
|
|
sym->st_shndx = chnk->ordinal() - 1 ;
|
|
sym->setBindingAndType(ELF::STB_LOCAL, ELF::STT_SECTION);
|
|
_symtable->addSymbol(sym);
|
|
}
|
|
}
|
|
for (const auto ssc : _stockSectionChunks){
|
|
for (const auto da : ssc->atoms()) {
|
|
_symtable->addSymbol(std::get<0>(da), ssc->ordinal() -1);
|
|
}
|
|
}
|
|
for (const UndefinedAtom *a : file.undefined()) {
|
|
_symtable->addSymbol(a, ELF::SHN_UNDEF);
|
|
}
|
|
|
|
for (const AbsoluteAtom *a : file.absolute()) {
|
|
_symtable->addSymbol(a, ELF::SHN_ABS);
|
|
}
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFWriter<target_endianness, is64Bits>
|
|
::buildAtomToAddressMap () {
|
|
|
|
// _atomToAddress is a DenseMap that maps an atom its file address.
|
|
// std::get<1>(ai) is the offset from the start of the section to the atom.
|
|
for (auto chunk : _stockSectionChunks){
|
|
for (auto &ai : chunk->atoms() ) {
|
|
_atomToAddress[std::get<0>(ai)] = chunk->address() + std::get<1>(ai);
|
|
}
|
|
}
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
void ELFWriter<target_endianness, is64Bits>::assignFileOffsets() {
|
|
DEBUG_WITH_TYPE("WriterELF-layout", dbgs()
|
|
<< "assign file offsets:\n");
|
|
uint64_t offset = 0;
|
|
uint64_t address = _options.type() == ELF::ET_REL ? 0 :
|
|
_options.baseAddress();
|
|
uint16_t chunkGroup;
|
|
auto chunkIt = _chunks.begin();
|
|
// first (two in case of ET_EXEC or ET_DYN) chunks is (are) not section(s)
|
|
(*chunkIt)->assignFileOffset(offset, address);
|
|
chunkIt++;
|
|
if (_options.type() == ELF::ET_EXEC ||
|
|
_options.type() == ELF::ET_DYN) {
|
|
(*chunkIt)->assignFileOffset(offset, address);
|
|
chunkIt++;
|
|
}
|
|
while (chunkIt != (_chunks.end() - 1) ) {
|
|
(*chunkIt)->assignFileOffset(offset, address);
|
|
if (_options.type() == ELF::ET_EXEC ||
|
|
_options.type() == ELF::ET_DYN) {
|
|
chunkGroup = (*chunkIt)->group();
|
|
chunkIt++;
|
|
// If the chunk group changes we start on new page
|
|
if (chunkGroup != (*chunkIt)->group() && (*chunkIt)->group() != CG_NO_LOAD
|
|
&& (*chunkIt)->group() != CG_FILE_END)
|
|
address = address + _options.pageSize();
|
|
} else {
|
|
chunkIt++;
|
|
}
|
|
}
|
|
(*chunkIt)->assignFileOffset(offset, address);
|
|
ehc->e_shoff(_sectionHeaderChunk->fileOffset());
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
error_code ELFWriter<target_endianness, is64Bits>
|
|
::writeFile(const lld::File &file, StringRef path) {
|
|
build(file);
|
|
|
|
uint64_t totalSize = _chunks.back()->fileOffset() + _chunks.back()->size();
|
|
|
|
OwningPtr<FileOutputBuffer> buffer;
|
|
error_code ec = FileOutputBuffer::create(path,
|
|
totalSize, buffer,
|
|
FileOutputBuffer::F_executable);
|
|
if (ec)
|
|
return ec;
|
|
|
|
for (auto chunk : _chunks) {
|
|
chunk->write(buffer->getBufferStart() + chunk->fileOffset());
|
|
}
|
|
return buffer->commit();
|
|
}
|
|
|
|
template<support::endianness target_endianness, bool is64Bits>
|
|
uint64_t ELFWriter<target_endianness, is64Bits>
|
|
::addressOfAtom(const Atom *atom) {
|
|
return _atomToAddress[atom];
|
|
}
|
|
} // namespace elf
|
|
|
|
Writer *createWriterELF(const WriterOptionsELF &options) {
|
|
if (!options.is64Bit() && options.endianness() == llvm::support::little)
|
|
return new lld::elf::ELFWriter<support::little, false>(options);
|
|
else if (options.is64Bit() && options.endianness() == llvm::support::little)
|
|
return new lld::elf::ELFWriter<support::little, true>(options);
|
|
else if (!options.is64Bit() && options.endianness() == llvm::support::big)
|
|
return new lld::elf::ELFWriter<support::big, false>(options);
|
|
else if (options.is64Bit() && options.endianness() == llvm::support::big)
|
|
return new lld::elf::ELFWriter<support::big, true>(options);
|
|
|
|
llvm_unreachable("Invalid Options!");
|
|
}
|
|
} // namespace lld
|