forked from OSchip/llvm-project
407 lines
14 KiB
C++
407 lines
14 KiB
C++
//===- lib/MC/ELFObjectWriter.h - ELF File Writer -------------------------===//
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//
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// The LLVM Compiler Infrastructure
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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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//
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// This file implements ELF object file writer information.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_MC_ELFOBJECTWRITER_H
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#define LLVM_MC_ELFOBJECTWRITER_H
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#include "MCELF.h"
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#include "llvm/ADT/OwningPtr.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCELFObjectWriter.h"
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#include "llvm/MC/MCELFSymbolFlags.h"
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#include "llvm/MC/MCObjectWriter.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCSymbol.h"
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#include <vector>
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namespace llvm {
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class MCSection;
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class MCDataFragment;
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class MCSectionELF;
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class ELFObjectWriter : public MCObjectWriter {
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protected:
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static bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind);
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static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant);
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static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout);
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static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
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bool Used, bool Renamed);
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static bool isLocal(const MCSymbolData &Data, bool isSignature,
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bool isUsedInReloc);
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static bool IsELFMetaDataSection(const MCSectionData &SD);
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static uint64_t DataSectionSize(const MCSectionData &SD);
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static uint64_t GetSectionFileSize(const MCAsmLayout &Layout,
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const MCSectionData &SD);
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static uint64_t GetSectionAddressSize(const MCAsmLayout &Layout,
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const MCSectionData &SD);
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void WriteDataSectionData(MCAssembler &Asm,
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const MCAsmLayout &Layout,
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const MCSectionELF &Section);
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/*static bool isFixupKindX86RIPRel(unsigned Kind) {
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return Kind == X86::reloc_riprel_4byte ||
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Kind == X86::reloc_riprel_4byte_movq_load;
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}*/
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/// ELFSymbolData - Helper struct for containing some precomputed
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/// information on symbols.
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struct ELFSymbolData {
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MCSymbolData *SymbolData;
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uint64_t StringIndex;
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uint32_t SectionIndex;
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// Support lexicographic sorting.
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bool operator<(const ELFSymbolData &RHS) const {
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if (MCELF::GetType(*SymbolData) == ELF::STT_FILE)
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return true;
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if (MCELF::GetType(*RHS.SymbolData) == ELF::STT_FILE)
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return false;
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return SymbolData->getSymbol().getName() <
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RHS.SymbolData->getSymbol().getName();
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}
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};
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/// @name Relocation Data
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/// @{
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struct ELFRelocationEntry {
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// Make these big enough for both 32-bit and 64-bit
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uint64_t r_offset;
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int Index;
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unsigned Type;
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const MCSymbol *Symbol;
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uint64_t r_addend;
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ELFRelocationEntry()
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: r_offset(0), Index(0), Type(0), Symbol(0), r_addend(0) {}
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ELFRelocationEntry(uint64_t RelocOffset, int Idx,
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unsigned RelType, const MCSymbol *Sym,
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uint64_t Addend)
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: r_offset(RelocOffset), Index(Idx), Type(RelType),
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Symbol(Sym), r_addend(Addend) {}
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// Support lexicographic sorting.
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bool operator<(const ELFRelocationEntry &RE) const {
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return RE.r_offset < r_offset;
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}
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};
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/// The target specific ELF writer instance.
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llvm::OwningPtr<MCELFObjectTargetWriter> TargetObjectWriter;
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SmallPtrSet<const MCSymbol *, 16> UsedInReloc;
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SmallPtrSet<const MCSymbol *, 16> WeakrefUsedInReloc;
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DenseMap<const MCSymbol *, const MCSymbol *> Renames;
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llvm::DenseMap<const MCSectionData*,
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std::vector<ELFRelocationEntry> > Relocations;
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DenseMap<const MCSection*, uint64_t> SectionStringTableIndex;
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/// @}
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/// @name Symbol Table Data
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/// @{
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SmallString<256> StringTable;
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std::vector<ELFSymbolData> LocalSymbolData;
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std::vector<ELFSymbolData> ExternalSymbolData;
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std::vector<ELFSymbolData> UndefinedSymbolData;
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/// @}
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bool NeedsGOT;
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bool NeedsSymtabShndx;
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// This holds the symbol table index of the last local symbol.
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unsigned LastLocalSymbolIndex;
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// This holds the .strtab section index.
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unsigned StringTableIndex;
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// This holds the .symtab section index.
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unsigned SymbolTableIndex;
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unsigned ShstrtabIndex;
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const MCSymbol *SymbolToReloc(const MCAssembler &Asm,
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const MCValue &Target,
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const MCFragment &F) const;
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// For arch-specific emission of explicit reloc symbol
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virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
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const MCValue &Target,
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const MCFragment &F,
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bool IsBSS) const {
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return NULL;
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}
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bool is64Bit() const { return TargetObjectWriter->is64Bit(); }
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bool hasRelocationAddend() const {
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return TargetObjectWriter->hasRelocationAddend();
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}
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public:
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ELFObjectWriter(MCELFObjectTargetWriter *MOTW,
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raw_ostream &_OS, bool IsLittleEndian)
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: MCObjectWriter(_OS, IsLittleEndian),
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TargetObjectWriter(MOTW),
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NeedsGOT(false), NeedsSymtabShndx(false){
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}
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virtual ~ELFObjectWriter();
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void WriteWord(uint64_t W) {
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if (is64Bit())
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Write64(W);
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else
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Write32(W);
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}
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void StringLE16(char *buf, uint16_t Value) {
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buf[0] = char(Value >> 0);
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buf[1] = char(Value >> 8);
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}
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void StringLE32(char *buf, uint32_t Value) {
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StringLE16(buf, uint16_t(Value >> 0));
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StringLE16(buf + 2, uint16_t(Value >> 16));
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}
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void StringLE64(char *buf, uint64_t Value) {
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StringLE32(buf, uint32_t(Value >> 0));
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StringLE32(buf + 4, uint32_t(Value >> 32));
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}
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void StringBE16(char *buf ,uint16_t Value) {
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buf[0] = char(Value >> 8);
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buf[1] = char(Value >> 0);
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}
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void StringBE32(char *buf, uint32_t Value) {
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StringBE16(buf, uint16_t(Value >> 16));
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StringBE16(buf + 2, uint16_t(Value >> 0));
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}
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void StringBE64(char *buf, uint64_t Value) {
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StringBE32(buf, uint32_t(Value >> 32));
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StringBE32(buf + 4, uint32_t(Value >> 0));
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}
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void String8(MCDataFragment &F, uint8_t Value) {
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char buf[1];
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buf[0] = Value;
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F.getContents() += StringRef(buf, 1);
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}
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void String16(MCDataFragment &F, uint16_t Value) {
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char buf[2];
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if (isLittleEndian())
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StringLE16(buf, Value);
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else
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StringBE16(buf, Value);
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F.getContents() += StringRef(buf, 2);
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}
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void String32(MCDataFragment &F, uint32_t Value) {
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char buf[4];
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if (isLittleEndian())
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StringLE32(buf, Value);
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else
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StringBE32(buf, Value);
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F.getContents() += StringRef(buf, 4);
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}
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void String64(MCDataFragment &F, uint64_t Value) {
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char buf[8];
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if (isLittleEndian())
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StringLE64(buf, Value);
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else
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StringBE64(buf, Value);
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F.getContents() += StringRef(buf, 8);
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}
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virtual void WriteHeader(uint64_t SectionDataSize, unsigned NumberOfSections);
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/// Default e_flags = 0
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virtual void WriteEFlags() { Write32(0); }
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virtual void WriteSymbolEntry(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
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uint64_t name, uint8_t info,
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uint64_t value, uint64_t size,
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uint8_t other, uint32_t shndx,
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bool Reserved);
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virtual void WriteSymbol(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
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ELFSymbolData &MSD,
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const MCAsmLayout &Layout);
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typedef DenseMap<const MCSectionELF*, uint32_t> SectionIndexMapTy;
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virtual void WriteSymbolTable(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
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const MCAssembler &Asm,
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const MCAsmLayout &Layout,
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const SectionIndexMapTy &SectionIndexMap);
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virtual void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
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const MCFragment *Fragment, const MCFixup &Fixup,
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MCValue Target, uint64_t &FixedValue);
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virtual uint64_t getSymbolIndexInSymbolTable(const MCAssembler &Asm,
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const MCSymbol *S);
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// Map from a group section to the signature symbol
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typedef DenseMap<const MCSectionELF*, const MCSymbol*> GroupMapTy;
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// Map from a signature symbol to the group section
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typedef DenseMap<const MCSymbol*, const MCSectionELF*> RevGroupMapTy;
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// Map from a section to the section with the relocations
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typedef DenseMap<const MCSectionELF*, const MCSectionELF*> RelMapTy;
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// Map from a section to its offset
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typedef DenseMap<const MCSectionELF*, uint64_t> SectionOffsetMapTy;
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/// ComputeSymbolTable - Compute the symbol table data
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///
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/// \param StringTable [out] - The string table data.
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/// \param StringIndexMap [out] - Map from symbol names to offsets in the
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/// string table.
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virtual void ComputeSymbolTable(MCAssembler &Asm,
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const SectionIndexMapTy &SectionIndexMap,
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RevGroupMapTy RevGroupMap,
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unsigned NumRegularSections);
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virtual void ComputeIndexMap(MCAssembler &Asm,
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SectionIndexMapTy &SectionIndexMap,
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const RelMapTy &RelMap);
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void CreateRelocationSections(MCAssembler &Asm, MCAsmLayout &Layout,
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RelMapTy &RelMap);
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void WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout,
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const RelMapTy &RelMap);
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virtual void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout,
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SectionIndexMapTy &SectionIndexMap,
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const RelMapTy &RelMap);
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// Create the sections that show up in the symbol table. Currently
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// those are the .note.GNU-stack section and the group sections.
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virtual void CreateIndexedSections(MCAssembler &Asm, MCAsmLayout &Layout,
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GroupMapTy &GroupMap,
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RevGroupMapTy &RevGroupMap,
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SectionIndexMapTy &SectionIndexMap,
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const RelMapTy &RelMap);
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virtual void ExecutePostLayoutBinding(MCAssembler &Asm,
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const MCAsmLayout &Layout);
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void WriteSectionHeader(MCAssembler &Asm, const GroupMapTy &GroupMap,
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const MCAsmLayout &Layout,
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const SectionIndexMapTy &SectionIndexMap,
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const SectionOffsetMapTy &SectionOffsetMap);
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void ComputeSectionOrder(MCAssembler &Asm,
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std::vector<const MCSectionELF*> &Sections);
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virtual void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
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uint64_t Address, uint64_t Offset,
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uint64_t Size, uint32_t Link, uint32_t Info,
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uint64_t Alignment, uint64_t EntrySize);
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virtual void WriteRelocationsFragment(const MCAssembler &Asm,
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MCDataFragment *F,
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const MCSectionData *SD);
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virtual bool
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IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
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const MCSymbolData &DataA,
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const MCFragment &FB,
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bool InSet,
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bool IsPCRel) const;
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virtual void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
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virtual void WriteSection(MCAssembler &Asm,
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const SectionIndexMapTy &SectionIndexMap,
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uint32_t GroupSymbolIndex,
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uint64_t Offset, uint64_t Size, uint64_t Alignment,
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const MCSectionELF &Section);
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protected:
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virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
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bool IsPCRel, bool IsRelocWithSymbol,
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int64_t Addend) = 0;
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};
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//===- X86ELFObjectWriter -------------------------------------------===//
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class X86ELFObjectWriter : public ELFObjectWriter {
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public:
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X86ELFObjectWriter(MCELFObjectTargetWriter *MOTW,
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raw_ostream &_OS,
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bool IsLittleEndian);
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virtual ~X86ELFObjectWriter();
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protected:
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virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
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bool IsPCRel, bool IsRelocWithSymbol,
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int64_t Addend);
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};
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//===- ARMELFObjectWriter -------------------------------------------===//
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class ARMELFObjectWriter : public ELFObjectWriter {
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public:
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// FIXME: MCAssembler can't yet return the Subtarget,
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enum { DefaultEABIVersion = 0x05000000U };
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ARMELFObjectWriter(MCELFObjectTargetWriter *MOTW,
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raw_ostream &_OS,
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bool IsLittleEndian);
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virtual ~ARMELFObjectWriter();
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virtual void WriteEFlags();
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protected:
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virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
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const MCValue &Target,
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const MCFragment &F,
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bool IsBSS) const;
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virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
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bool IsPCRel, bool IsRelocWithSymbol,
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int64_t Addend);
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};
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//===- MBlazeELFObjectWriter -------------------------------------------===//
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class MBlazeELFObjectWriter : public ELFObjectWriter {
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public:
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MBlazeELFObjectWriter(MCELFObjectTargetWriter *MOTW,
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raw_ostream &_OS,
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bool IsLittleEndian);
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virtual ~MBlazeELFObjectWriter();
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protected:
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virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
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bool IsPCRel, bool IsRelocWithSymbol,
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int64_t Addend);
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};
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}
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#endif
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