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.file records are supposed to have a section identifier of 65534 (IMAGE_SCN_DEBUG) rather than 0. This is spelt out clearly within the PE/COFF specification. Fix this minor oversight with the implementation for support for .file records. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207851 91177308-0d34-0410-b5e6-96231b3b80d8
1021 lines
34 KiB
C++
1021 lines
34 KiB
C++
//===-- llvm/MC/WinCOFFObjectWriter.cpp -------------------------*- C++ -*-===//
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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 contains an implementation of a Win32 COFF object file writer.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/MC/MCWinCOFFObjectWriter.h"
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#include "llvm/ADT/DenseMap.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/ADT/STLExtras.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/MC/MCAsmLayout.h"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCObjectWriter.h"
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#include "llvm/MC/MCSection.h"
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#include "llvm/MC/MCSectionCOFF.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/Support/COFF.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/TimeValue.h"
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#include <cstdio>
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using namespace llvm;
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#define DEBUG_TYPE "WinCOFFObjectWriter"
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namespace {
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typedef SmallString<COFF::NameSize> name;
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enum AuxiliaryType {
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ATFunctionDefinition,
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ATbfAndefSymbol,
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ATWeakExternal,
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ATFile,
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ATSectionDefinition
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};
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struct AuxSymbol {
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AuxiliaryType AuxType;
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COFF::Auxiliary Aux;
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};
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class COFFSymbol;
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class COFFSection;
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class COFFSymbol {
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public:
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COFF::symbol Data;
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typedef SmallVector<AuxSymbol, 1> AuxiliarySymbols;
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name Name;
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int Index;
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AuxiliarySymbols Aux;
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COFFSymbol *Other;
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COFFSection *Section;
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int Relocations;
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MCSymbolData const *MCData;
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COFFSymbol(StringRef name);
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size_t size() const;
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void set_name_offset(uint32_t Offset);
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bool should_keep() const;
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};
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// This class contains staging data for a COFF relocation entry.
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struct COFFRelocation {
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COFF::relocation Data;
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COFFSymbol *Symb;
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COFFRelocation() : Symb(nullptr) {}
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static size_t size() { return COFF::RelocationSize; }
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};
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typedef std::vector<COFFRelocation> relocations;
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class COFFSection {
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public:
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COFF::section Header;
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std::string Name;
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int Number;
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MCSectionData const *MCData;
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COFFSymbol *Symbol;
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relocations Relocations;
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COFFSection(StringRef name);
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static size_t size();
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};
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// This class holds the COFF string table.
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class StringTable {
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typedef StringMap<size_t> map;
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map Map;
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void update_length();
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public:
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std::vector<char> Data;
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StringTable();
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size_t size() const;
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size_t insert(StringRef String);
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};
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class WinCOFFObjectWriter : public MCObjectWriter {
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public:
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typedef std::vector<std::unique_ptr<COFFSymbol>> symbols;
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typedef std::vector<std::unique_ptr<COFFSection>> sections;
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typedef DenseMap<MCSymbol const *, COFFSymbol *> symbol_map;
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typedef DenseMap<MCSection const *, COFFSection *> section_map;
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std::unique_ptr<MCWinCOFFObjectTargetWriter> TargetObjectWriter;
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// Root level file contents.
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COFF::header Header;
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sections Sections;
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symbols Symbols;
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StringTable Strings;
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// Maps used during object file creation.
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section_map SectionMap;
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symbol_map SymbolMap;
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WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW, raw_ostream &OS);
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COFFSymbol *createSymbol(StringRef Name);
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COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol * Symbol);
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COFFSection *createSection(StringRef Name);
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template <typename object_t, typename list_t>
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object_t *createCOFFEntity(StringRef Name, list_t &List);
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void DefineSection(MCSectionData const &SectionData);
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void DefineSymbol(MCSymbolData const &SymbolData, MCAssembler &Assembler,
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const MCAsmLayout &Layout);
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void MakeSymbolReal(COFFSymbol &S, size_t Index);
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void MakeSectionReal(COFFSection &S, size_t Number);
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bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);
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bool IsPhysicalSection(COFFSection *S);
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// Entity writing methods.
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void WriteFileHeader(const COFF::header &Header);
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void WriteSymbol(const COFFSymbol &S);
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void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
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void WriteSectionHeader(const COFF::section &S);
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void WriteRelocation(const COFF::relocation &R);
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// MCObjectWriter interface implementation.
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void ExecutePostLayoutBinding(MCAssembler &Asm,
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const MCAsmLayout &Layout) override;
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void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
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const MCFragment *Fragment, const MCFixup &Fixup,
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MCValue Target, bool &IsPCRel,
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uint64_t &FixedValue) override;
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void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
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};
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}
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static inline void write_uint32_le(void *Data, uint32_t const &Value) {
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uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
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Ptr[0] = (Value & 0x000000FF) >> 0;
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Ptr[1] = (Value & 0x0000FF00) >> 8;
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Ptr[2] = (Value & 0x00FF0000) >> 16;
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Ptr[3] = (Value & 0xFF000000) >> 24;
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}
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//------------------------------------------------------------------------------
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// Symbol class implementation
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COFFSymbol::COFFSymbol(StringRef name)
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: Name(name.begin(), name.end())
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, Other(nullptr)
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, Section(nullptr)
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, Relocations(0)
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, MCData(nullptr) {
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memset(&Data, 0, sizeof(Data));
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}
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size_t COFFSymbol::size() const {
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return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
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}
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// In the case that the name does not fit within 8 bytes, the offset
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// into the string table is stored in the last 4 bytes instead, leaving
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// the first 4 bytes as 0.
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void COFFSymbol::set_name_offset(uint32_t Offset) {
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write_uint32_le(Data.Name + 0, 0);
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write_uint32_le(Data.Name + 4, Offset);
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}
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/// logic to decide if the symbol should be reported in the symbol table
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bool COFFSymbol::should_keep() const {
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// no section means its external, keep it
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if (!Section)
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return true;
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// if it has relocations pointing at it, keep it
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if (Relocations > 0) {
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assert(Section->Number != -1 && "Sections with relocations must be real!");
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return true;
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}
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// if the section its in is being droped, drop it
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if (Section->Number == -1)
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return false;
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// if it is the section symbol, keep it
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if (Section->Symbol == this)
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return true;
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// if its temporary, drop it
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if (MCData && MCData->getSymbol().isTemporary())
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return false;
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// otherwise, keep it
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return true;
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}
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//------------------------------------------------------------------------------
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// Section class implementation
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COFFSection::COFFSection(StringRef name)
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: Name(name)
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, MCData(nullptr)
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, Symbol(nullptr) {
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memset(&Header, 0, sizeof(Header));
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}
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size_t COFFSection::size() {
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return COFF::SectionSize;
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}
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//------------------------------------------------------------------------------
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// StringTable class implementation
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/// Write the length of the string table into Data.
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/// The length of the string table includes uint32 length header.
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void StringTable::update_length() {
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write_uint32_le(&Data.front(), Data.size());
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}
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StringTable::StringTable() {
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// The string table data begins with the length of the entire string table
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// including the length header. Allocate space for this header.
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Data.resize(4);
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update_length();
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}
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size_t StringTable::size() const {
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return Data.size();
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}
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/// Add String to the table iff it is not already there.
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/// @returns the index into the string table where the string is now located.
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size_t StringTable::insert(StringRef String) {
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map::iterator i = Map.find(String);
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if (i != Map.end())
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return i->second;
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size_t Offset = Data.size();
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// Insert string data into string table.
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Data.insert(Data.end(), String.begin(), String.end());
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Data.push_back('\0');
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// Put a reference to it in the map.
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Map[String] = Offset;
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// Update the internal length field.
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update_length();
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return Offset;
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}
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//------------------------------------------------------------------------------
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// WinCOFFObjectWriter class implementation
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WinCOFFObjectWriter::WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
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raw_ostream &OS)
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: MCObjectWriter(OS, true)
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, TargetObjectWriter(MOTW) {
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memset(&Header, 0, sizeof(Header));
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Header.Machine = TargetObjectWriter->getMachine();
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}
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COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
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return createCOFFEntity<COFFSymbol>(Name, Symbols);
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}
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COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol * Symbol){
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symbol_map::iterator i = SymbolMap.find(Symbol);
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if (i != SymbolMap.end())
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return i->second;
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COFFSymbol *RetSymbol
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= createCOFFEntity<COFFSymbol>(Symbol->getName(), Symbols);
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SymbolMap[Symbol] = RetSymbol;
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return RetSymbol;
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}
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COFFSection *WinCOFFObjectWriter::createSection(StringRef Name) {
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return createCOFFEntity<COFFSection>(Name, Sections);
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}
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/// A template used to lookup or create a symbol/section, and initialize it if
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/// needed.
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template <typename object_t, typename list_t>
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object_t *WinCOFFObjectWriter::createCOFFEntity(StringRef Name,
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list_t &List) {
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List.push_back(make_unique<object_t>(Name));
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return List.back().get();
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}
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/// This function takes a section data object from the assembler
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/// and creates the associated COFF section staging object.
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void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
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assert(SectionData.getSection().getVariant() == MCSection::SV_COFF
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&& "Got non-COFF section in the COFF backend!");
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// FIXME: Not sure how to verify this (at least in a debug build).
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MCSectionCOFF const &Sec =
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static_cast<MCSectionCOFF const &>(SectionData.getSection());
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COFFSection *coff_section = createSection(Sec.getSectionName());
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COFFSymbol *coff_symbol = createSymbol(Sec.getSectionName());
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coff_section->Symbol = coff_symbol;
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coff_symbol->Section = coff_section;
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coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
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// In this case the auxiliary symbol is a Section Definition.
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coff_symbol->Aux.resize(1);
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memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
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coff_symbol->Aux[0].AuxType = ATSectionDefinition;
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coff_symbol->Aux[0].Aux.SectionDefinition.Selection = Sec.getSelection();
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coff_section->Header.Characteristics = Sec.getCharacteristics();
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uint32_t &Characteristics = coff_section->Header.Characteristics;
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switch (SectionData.getAlignment()) {
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case 1: Characteristics |= COFF::IMAGE_SCN_ALIGN_1BYTES; break;
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case 2: Characteristics |= COFF::IMAGE_SCN_ALIGN_2BYTES; break;
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case 4: Characteristics |= COFF::IMAGE_SCN_ALIGN_4BYTES; break;
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case 8: Characteristics |= COFF::IMAGE_SCN_ALIGN_8BYTES; break;
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case 16: Characteristics |= COFF::IMAGE_SCN_ALIGN_16BYTES; break;
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case 32: Characteristics |= COFF::IMAGE_SCN_ALIGN_32BYTES; break;
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case 64: Characteristics |= COFF::IMAGE_SCN_ALIGN_64BYTES; break;
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case 128: Characteristics |= COFF::IMAGE_SCN_ALIGN_128BYTES; break;
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case 256: Characteristics |= COFF::IMAGE_SCN_ALIGN_256BYTES; break;
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case 512: Characteristics |= COFF::IMAGE_SCN_ALIGN_512BYTES; break;
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case 1024: Characteristics |= COFF::IMAGE_SCN_ALIGN_1024BYTES; break;
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case 2048: Characteristics |= COFF::IMAGE_SCN_ALIGN_2048BYTES; break;
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case 4096: Characteristics |= COFF::IMAGE_SCN_ALIGN_4096BYTES; break;
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case 8192: Characteristics |= COFF::IMAGE_SCN_ALIGN_8192BYTES; break;
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default:
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llvm_unreachable("unsupported section alignment");
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}
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// Bind internal COFF section to MC section.
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coff_section->MCData = &SectionData;
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SectionMap[&SectionData.getSection()] = coff_section;
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}
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static uint64_t getSymbolValue(const MCSymbolData &Data,
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const MCAsmLayout &Layout) {
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if (Data.isCommon() && Data.isExternal())
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return Data.getCommonSize();
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uint64_t Res;
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if (!Layout.getSymbolOffset(&Data, Res))
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return 0;
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return Res;
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}
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/// This function takes a symbol data object from the assembler
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/// and creates the associated COFF symbol staging object.
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void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
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MCAssembler &Assembler,
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const MCAsmLayout &Layout) {
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MCSymbol const &Symbol = SymbolData.getSymbol();
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COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&Symbol);
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SymbolMap[&Symbol] = coff_symbol;
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if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
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coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
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if (Symbol.isVariable()) {
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const MCSymbolRefExpr *SymRef =
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dyn_cast<MCSymbolRefExpr>(Symbol.getVariableValue());
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if (!SymRef)
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report_fatal_error("Weak externals may only alias symbols");
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coff_symbol->Other = GetOrCreateCOFFSymbol(&SymRef->getSymbol());
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} else {
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std::string WeakName = std::string(".weak.")
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+ Symbol.getName().str()
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+ ".default";
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COFFSymbol *WeakDefault = createSymbol(WeakName);
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WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
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WeakDefault->Data.StorageClass = COFF::IMAGE_SYM_CLASS_EXTERNAL;
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WeakDefault->Data.Type = 0;
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WeakDefault->Data.Value = 0;
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coff_symbol->Other = WeakDefault;
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}
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// Setup the Weak External auxiliary symbol.
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coff_symbol->Aux.resize(1);
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memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
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coff_symbol->Aux[0].AuxType = ATWeakExternal;
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coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
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coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
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COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
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coff_symbol->MCData = &SymbolData;
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} else {
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const MCSymbolData &ResSymData = Assembler.getSymbolData(Symbol);
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const MCSymbol *Base = Layout.getBaseSymbol(Symbol);
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coff_symbol->Data.Value = getSymbolValue(ResSymData, Layout);
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coff_symbol->Data.Type = (ResSymData.getFlags() & 0x0000FFFF) >> 0;
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coff_symbol->Data.StorageClass = (ResSymData.getFlags() & 0x00FF0000) >> 16;
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// If no storage class was specified in the streamer, define it here.
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if (coff_symbol->Data.StorageClass == 0) {
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bool external = ResSymData.isExternal() || !ResSymData.Fragment;
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coff_symbol->Data.StorageClass =
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external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
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}
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if (!Base) {
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coff_symbol->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
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} else {
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const MCSymbolData &BaseData = Assembler.getSymbolData(*Base);
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if (BaseData.Fragment)
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coff_symbol->Section =
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SectionMap[&BaseData.Fragment->getParent()->getSection()];
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}
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coff_symbol->MCData = &ResSymData;
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}
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}
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// Maximum offsets for different string table entry encodings.
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static const unsigned Max6DecimalOffset = 999999;
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static const unsigned Max7DecimalOffset = 9999999;
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static const uint64_t MaxBase64Offset = 0xFFFFFFFFFULL; // 64^6, including 0
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// Encode a string table entry offset in base 64, padded to 6 chars, and
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// prefixed with a double slash: '//AAAAAA', '//AAAAAB', ...
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// Buffer must be at least 8 bytes large. No terminating null appended.
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static void encodeBase64StringEntry(char* Buffer, uint64_t Value) {
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assert(Value > Max7DecimalOffset && Value <= MaxBase64Offset &&
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"Illegal section name encoding for value");
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static const char Alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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"abcdefghijklmnopqrstuvwxyz"
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"0123456789+/";
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Buffer[0] = '/';
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Buffer[1] = '/';
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char* Ptr = Buffer + 7;
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for (unsigned i = 0; i < 6; ++i) {
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unsigned Rem = Value % 64;
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Value /= 64;
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*(Ptr--) = Alphabet[Rem];
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}
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}
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/// making a section real involves assigned it a number and putting
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/// name into the string table if needed
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void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
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|
if (S.Name.size() > COFF::NameSize) {
|
|
uint64_t StringTableEntry = Strings.insert(S.Name.c_str());
|
|
|
|
if (StringTableEntry <= Max6DecimalOffset) {
|
|
std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
|
|
} else if (StringTableEntry <= Max7DecimalOffset) {
|
|
// With seven digits, we have to skip the terminating null. Because
|
|
// sprintf always appends it, we use a larger temporary buffer.
|
|
char buffer[9] = { };
|
|
std::sprintf(buffer, "/%d", unsigned(StringTableEntry));
|
|
std::memcpy(S.Header.Name, buffer, 8);
|
|
} else if (StringTableEntry <= MaxBase64Offset) {
|
|
// Starting with 10,000,000, offsets are encoded as base64.
|
|
encodeBase64StringEntry(S.Header.Name, StringTableEntry);
|
|
} else {
|
|
report_fatal_error("COFF string table is greater than 64 GB.");
|
|
}
|
|
} else
|
|
std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
|
|
|
|
S.Number = Number;
|
|
S.Symbol->Data.SectionNumber = S.Number;
|
|
S.Symbol->Aux[0].Aux.SectionDefinition.Number = S.Number;
|
|
}
|
|
|
|
void WinCOFFObjectWriter::MakeSymbolReal(COFFSymbol &S, size_t Index) {
|
|
if (S.Name.size() > COFF::NameSize) {
|
|
size_t StringTableEntry = Strings.insert(S.Name.c_str());
|
|
|
|
S.set_name_offset(StringTableEntry);
|
|
} else
|
|
std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
|
|
S.Index = Index;
|
|
}
|
|
|
|
bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
|
|
MCAssembler &Asm) {
|
|
// This doesn't seem to be right. Strings referred to from the .data section
|
|
// need symbols so they can be linked to code in the .text section right?
|
|
|
|
// return Asm.isSymbolLinkerVisible (&SymbolData);
|
|
|
|
// For now, all non-variable symbols are exported,
|
|
// the linker will sort the rest out for us.
|
|
return SymbolData.isExternal() || !SymbolData.getSymbol().isVariable();
|
|
}
|
|
|
|
bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) {
|
|
return (S->Header.Characteristics
|
|
& COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
// entity writing methods
|
|
|
|
void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
|
|
WriteLE16(Header.Machine);
|
|
WriteLE16(Header.NumberOfSections);
|
|
WriteLE32(Header.TimeDateStamp);
|
|
WriteLE32(Header.PointerToSymbolTable);
|
|
WriteLE32(Header.NumberOfSymbols);
|
|
WriteLE16(Header.SizeOfOptionalHeader);
|
|
WriteLE16(Header.Characteristics);
|
|
}
|
|
|
|
void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol &S) {
|
|
WriteBytes(StringRef(S.Data.Name, COFF::NameSize));
|
|
WriteLE32(S.Data.Value);
|
|
WriteLE16(S.Data.SectionNumber);
|
|
WriteLE16(S.Data.Type);
|
|
Write8(S.Data.StorageClass);
|
|
Write8(S.Data.NumberOfAuxSymbols);
|
|
WriteAuxiliarySymbols(S.Aux);
|
|
}
|
|
|
|
void WinCOFFObjectWriter::WriteAuxiliarySymbols(
|
|
const COFFSymbol::AuxiliarySymbols &S) {
|
|
for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
|
|
i != e; ++i) {
|
|
switch(i->AuxType) {
|
|
case ATFunctionDefinition:
|
|
WriteLE32(i->Aux.FunctionDefinition.TagIndex);
|
|
WriteLE32(i->Aux.FunctionDefinition.TotalSize);
|
|
WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
|
|
WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
|
|
WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
|
|
break;
|
|
case ATbfAndefSymbol:
|
|
WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
|
|
WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
|
|
WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
|
|
WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
|
|
WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
|
|
break;
|
|
case ATWeakExternal:
|
|
WriteLE32(i->Aux.WeakExternal.TagIndex);
|
|
WriteLE32(i->Aux.WeakExternal.Characteristics);
|
|
WriteZeros(sizeof(i->Aux.WeakExternal.unused));
|
|
break;
|
|
case ATFile:
|
|
WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
|
|
sizeof(i->Aux.File.FileName)));
|
|
break;
|
|
case ATSectionDefinition:
|
|
WriteLE32(i->Aux.SectionDefinition.Length);
|
|
WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
|
|
WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
|
|
WriteLE32(i->Aux.SectionDefinition.CheckSum);
|
|
WriteLE16(i->Aux.SectionDefinition.Number);
|
|
Write8(i->Aux.SectionDefinition.Selection);
|
|
WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
|
|
WriteBytes(StringRef(S.Name, COFF::NameSize));
|
|
|
|
WriteLE32(S.VirtualSize);
|
|
WriteLE32(S.VirtualAddress);
|
|
WriteLE32(S.SizeOfRawData);
|
|
WriteLE32(S.PointerToRawData);
|
|
WriteLE32(S.PointerToRelocations);
|
|
WriteLE32(S.PointerToLineNumbers);
|
|
WriteLE16(S.NumberOfRelocations);
|
|
WriteLE16(S.NumberOfLineNumbers);
|
|
WriteLE32(S.Characteristics);
|
|
}
|
|
|
|
void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
|
|
WriteLE32(R.VirtualAddress);
|
|
WriteLE32(R.SymbolTableIndex);
|
|
WriteLE16(R.Type);
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// MCObjectWriter interface implementations
|
|
|
|
void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
|
|
const MCAsmLayout &Layout) {
|
|
// "Define" each section & symbol. This creates section & symbol
|
|
// entries in the staging area.
|
|
|
|
static_assert(sizeof(((COFF::AuxiliaryFile *)nullptr)->FileName) == COFF::SymbolSize,
|
|
"size mismatch for COFF::AuxiliaryFile::FileName");
|
|
for (auto FI = Asm.file_names_begin(), FE = Asm.file_names_end();
|
|
FI != FE; ++FI) {
|
|
// round up to calculate the number of auxiliary symbols required
|
|
unsigned Count = (FI->size() + COFF::SymbolSize - 1) / COFF::SymbolSize;
|
|
|
|
COFFSymbol *file = createSymbol(".file");
|
|
file->Data.SectionNumber = COFF::IMAGE_SYM_DEBUG;
|
|
file->Data.StorageClass = COFF::IMAGE_SYM_CLASS_FILE;
|
|
file->Aux.resize(Count);
|
|
|
|
unsigned Offset = 0;
|
|
unsigned Length = FI->size();
|
|
for (auto & Aux : file->Aux) {
|
|
Aux.AuxType = ATFile;
|
|
|
|
if (Length > COFF::SymbolSize) {
|
|
memcpy(Aux.Aux.File.FileName, FI->c_str() + Offset, COFF::SymbolSize);
|
|
Length = Length - COFF::SymbolSize;
|
|
} else {
|
|
memcpy(Aux.Aux.File.FileName, FI->c_str() + Offset, Length);
|
|
memset(&Aux.Aux.File.FileName[Length], 0, COFF::SymbolSize - Length);
|
|
Length = 0;
|
|
}
|
|
|
|
Offset = Offset + COFF::SymbolSize;
|
|
}
|
|
}
|
|
|
|
for (const auto & Section : Asm)
|
|
DefineSection(Section);
|
|
|
|
for (MCSymbolData &SD : Asm.symbols())
|
|
if (ExportSymbol(SD, Asm))
|
|
DefineSymbol(SD, Asm, Layout);
|
|
}
|
|
|
|
void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
|
|
const MCAsmLayout &Layout,
|
|
const MCFragment *Fragment,
|
|
const MCFixup &Fixup,
|
|
MCValue Target,
|
|
bool &IsPCRel,
|
|
uint64_t &FixedValue) {
|
|
assert(Target.getSymA() && "Relocation must reference a symbol!");
|
|
|
|
const MCSymbol &Symbol = Target.getSymA()->getSymbol();
|
|
const MCSymbol &A = Symbol.AliasedSymbol();
|
|
if (!Asm.hasSymbolData(A))
|
|
Asm.getContext().FatalError(
|
|
Fixup.getLoc(),
|
|
Twine("symbol '") + A.getName() + "' can not be undefined");
|
|
|
|
const MCSymbolData &A_SD = Asm.getSymbolData(A);
|
|
|
|
MCSectionData const *SectionData = Fragment->getParent();
|
|
|
|
// Mark this symbol as requiring an entry in the symbol table.
|
|
assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
|
|
"Section must already have been defined in ExecutePostLayoutBinding!");
|
|
assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
|
|
"Symbol must already have been defined in ExecutePostLayoutBinding!");
|
|
|
|
COFFSection *coff_section = SectionMap[&SectionData->getSection()];
|
|
COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
|
|
const MCSymbolRefExpr *SymB = Target.getSymB();
|
|
bool CrossSection = false;
|
|
|
|
if (SymB) {
|
|
const MCSymbol *B = &SymB->getSymbol();
|
|
const MCSymbolData &B_SD = Asm.getSymbolData(*B);
|
|
if (!B_SD.getFragment())
|
|
Asm.getContext().FatalError(
|
|
Fixup.getLoc(),
|
|
Twine("symbol '") + B->getName() +
|
|
"' can not be undefined in a subtraction expression");
|
|
|
|
if (!A_SD.getFragment())
|
|
Asm.getContext().FatalError(
|
|
Fixup.getLoc(),
|
|
Twine("symbol '") + Symbol.getName() +
|
|
"' can not be undefined in a subtraction expression");
|
|
|
|
CrossSection = &Symbol.getSection() != &B->getSection();
|
|
|
|
// Offset of the symbol in the section
|
|
int64_t a = Layout.getSymbolOffset(&B_SD);
|
|
|
|
// Ofeset of the relocation in the section
|
|
int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
|
|
|
|
FixedValue = b - a;
|
|
// In the case where we have SymbA and SymB, we just need to store the delta
|
|
// between the two symbols. Update FixedValue to account for the delta, and
|
|
// skip recording the relocation.
|
|
if (!CrossSection)
|
|
return;
|
|
} else {
|
|
FixedValue = Target.getConstant();
|
|
}
|
|
|
|
COFFRelocation Reloc;
|
|
|
|
Reloc.Data.SymbolTableIndex = 0;
|
|
Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
|
|
|
|
// Turn relocations for temporary symbols into section relocations.
|
|
if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
|
|
Reloc.Symb = coff_symbol->Section->Symbol;
|
|
FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
|
|
+ coff_symbol->MCData->getOffset();
|
|
} else
|
|
Reloc.Symb = coff_symbol;
|
|
|
|
++Reloc.Symb->Relocations;
|
|
|
|
Reloc.Data.VirtualAddress += Fixup.getOffset();
|
|
Reloc.Data.Type = TargetObjectWriter->getRelocType(Target, Fixup,
|
|
CrossSection);
|
|
|
|
// FIXME: Can anyone explain what this does other than adjust for the size
|
|
// of the offset?
|
|
if ((Header.Machine == COFF::IMAGE_FILE_MACHINE_AMD64 &&
|
|
Reloc.Data.Type == COFF::IMAGE_REL_AMD64_REL32) ||
|
|
(Header.Machine == COFF::IMAGE_FILE_MACHINE_I386 &&
|
|
Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32))
|
|
FixedValue += 4;
|
|
|
|
if (Header.Machine == COFF::IMAGE_FILE_MACHINE_ARMNT) {
|
|
switch (Reloc.Data.Type) {
|
|
case COFF::IMAGE_REL_ARM_ABSOLUTE:
|
|
case COFF::IMAGE_REL_ARM_ADDR32:
|
|
case COFF::IMAGE_REL_ARM_ADDR32NB:
|
|
case COFF::IMAGE_REL_ARM_TOKEN:
|
|
case COFF::IMAGE_REL_ARM_SECTION:
|
|
case COFF::IMAGE_REL_ARM_SECREL:
|
|
break;
|
|
case COFF::IMAGE_REL_ARM_BRANCH11:
|
|
case COFF::IMAGE_REL_ARM_BLX11:
|
|
// IMAGE_REL_ARM_BRANCH11 and IMAGE_REL_ARM_BLX11 are only used for
|
|
// pre-ARMv7, which implicitly rules it out of ARMNT (it would be valid
|
|
// for Windows CE).
|
|
case COFF::IMAGE_REL_ARM_BRANCH24:
|
|
case COFF::IMAGE_REL_ARM_BLX24:
|
|
case COFF::IMAGE_REL_ARM_MOV32A:
|
|
// IMAGE_REL_ARM_BRANCH24, IMAGE_REL_ARM_BLX24, IMAGE_REL_ARM_MOV32A are
|
|
// only used for ARM mode code, which is documented as being unsupported
|
|
// by Windows on ARM. Emperical proof indicates that masm is able to
|
|
// generate the relocations however the rest of the MSVC toolchain is
|
|
// unable to handle it.
|
|
llvm_unreachable("unsupported relocation");
|
|
break;
|
|
case COFF::IMAGE_REL_ARM_MOV32T:
|
|
break;
|
|
case COFF::IMAGE_REL_ARM_BRANCH20T:
|
|
case COFF::IMAGE_REL_ARM_BRANCH24T:
|
|
case COFF::IMAGE_REL_ARM_BLX23T:
|
|
// IMAGE_REL_BRANCH20T, IMAGE_REL_ARM_BRANCH24T, IMAGE_REL_ARM_BLX23T all
|
|
// perform a 4 byte adjustment to the relocation. Relative branches are
|
|
// offset by 4 on ARM, however, because there is no RELA relocations, all
|
|
// branches are offset by 4.
|
|
FixedValue = FixedValue + 4;
|
|
break;
|
|
}
|
|
}
|
|
|
|
coff_section->Relocations.push_back(Reloc);
|
|
}
|
|
|
|
void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
|
|
const MCAsmLayout &Layout) {
|
|
// Assign symbol and section indexes and offsets.
|
|
Header.NumberOfSections = 0;
|
|
|
|
DenseMap<COFFSection *, uint16_t> SectionIndices;
|
|
for (auto & Section : Sections) {
|
|
if (Layout.getSectionAddressSize(Section->MCData) > 0) {
|
|
size_t Number = ++Header.NumberOfSections;
|
|
SectionIndices[Section.get()] = Number;
|
|
MakeSectionReal(*Section, Number);
|
|
} else {
|
|
Section->Number = -1;
|
|
}
|
|
}
|
|
|
|
Header.NumberOfSymbols = 0;
|
|
|
|
for (auto & Symbol : Symbols) {
|
|
// Update section number & offset for symbols that have them.
|
|
if (Symbol->Section)
|
|
Symbol->Data.SectionNumber = Symbol->Section->Number;
|
|
|
|
if (Symbol->should_keep()) {
|
|
MakeSymbolReal(*Symbol, Header.NumberOfSymbols++);
|
|
|
|
// Update auxiliary symbol info.
|
|
Symbol->Data.NumberOfAuxSymbols = Symbol->Aux.size();
|
|
Header.NumberOfSymbols += Symbol->Data.NumberOfAuxSymbols;
|
|
} else
|
|
Symbol->Index = -1;
|
|
}
|
|
|
|
// Fixup weak external references.
|
|
for (auto & Symbol : Symbols) {
|
|
if (Symbol->Other) {
|
|
assert(Symbol->Index != -1);
|
|
assert(Symbol->Aux.size() == 1 && "Symbol must contain one aux symbol!");
|
|
assert(Symbol->Aux[0].AuxType == ATWeakExternal &&
|
|
"Symbol's aux symbol must be a Weak External!");
|
|
Symbol->Aux[0].Aux.WeakExternal.TagIndex = Symbol->Other->Index;
|
|
}
|
|
}
|
|
|
|
// Fixup associative COMDAT sections.
|
|
for (auto & Section : Sections) {
|
|
if (Section->Symbol->Aux[0].Aux.SectionDefinition.Selection !=
|
|
COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
|
|
continue;
|
|
|
|
const MCSectionCOFF &MCSec =
|
|
static_cast<const MCSectionCOFF &>(Section->MCData->getSection());
|
|
|
|
COFFSection *Assoc = SectionMap.lookup(MCSec.getAssocSection());
|
|
if (!Assoc)
|
|
report_fatal_error(Twine("Missing associated COMDAT section ") +
|
|
MCSec.getAssocSection()->getSectionName() +
|
|
" for section " + MCSec.getSectionName());
|
|
|
|
// Skip this section if the associated section is unused.
|
|
if (Assoc->Number == -1)
|
|
continue;
|
|
|
|
Section->Symbol->Aux[0].Aux.SectionDefinition.Number = SectionIndices[Assoc];
|
|
}
|
|
|
|
|
|
// Assign file offsets to COFF object file structures.
|
|
|
|
unsigned offset = 0;
|
|
|
|
offset += COFF::HeaderSize;
|
|
offset += COFF::SectionSize * Header.NumberOfSections;
|
|
|
|
for (const auto & Section : Asm) {
|
|
COFFSection *Sec = SectionMap[&Section.getSection()];
|
|
|
|
if (Sec->Number == -1)
|
|
continue;
|
|
|
|
Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(&Section);
|
|
|
|
if (IsPhysicalSection(Sec)) {
|
|
Sec->Header.PointerToRawData = offset;
|
|
|
|
offset += Sec->Header.SizeOfRawData;
|
|
}
|
|
|
|
if (Sec->Relocations.size() > 0) {
|
|
bool RelocationsOverflow = Sec->Relocations.size() >= 0xffff;
|
|
|
|
if (RelocationsOverflow) {
|
|
// Signal overflow by setting NumberOfSections to max value. Actual
|
|
// size is found in reloc #0. Microsoft tools understand this.
|
|
Sec->Header.NumberOfRelocations = 0xffff;
|
|
} else {
|
|
Sec->Header.NumberOfRelocations = Sec->Relocations.size();
|
|
}
|
|
Sec->Header.PointerToRelocations = offset;
|
|
|
|
if (RelocationsOverflow) {
|
|
// Reloc #0 will contain actual count, so make room for it.
|
|
offset += COFF::RelocationSize;
|
|
}
|
|
|
|
offset += COFF::RelocationSize * Sec->Relocations.size();
|
|
|
|
for (auto & Relocation : Sec->Relocations) {
|
|
assert(Relocation.Symb->Index != -1);
|
|
Relocation.Data.SymbolTableIndex = Relocation.Symb->Index;
|
|
}
|
|
}
|
|
|
|
assert(Sec->Symbol->Aux.size() == 1 &&
|
|
"Section's symbol must have one aux!");
|
|
AuxSymbol &Aux = Sec->Symbol->Aux[0];
|
|
assert(Aux.AuxType == ATSectionDefinition &&
|
|
"Section's symbol's aux symbol must be a Section Definition!");
|
|
Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
|
|
Aux.Aux.SectionDefinition.NumberOfRelocations =
|
|
Sec->Header.NumberOfRelocations;
|
|
Aux.Aux.SectionDefinition.NumberOfLinenumbers =
|
|
Sec->Header.NumberOfLineNumbers;
|
|
}
|
|
|
|
Header.PointerToSymbolTable = offset;
|
|
|
|
// We want a deterministic output. It looks like GNU as also writes 0 in here.
|
|
Header.TimeDateStamp = 0;
|
|
|
|
// Write it all to disk...
|
|
WriteFileHeader(Header);
|
|
|
|
{
|
|
sections::iterator i, ie;
|
|
MCAssembler::const_iterator j, je;
|
|
|
|
for (auto & Section : Sections) {
|
|
if (Section->Number != -1) {
|
|
if (Section->Relocations.size() >= 0xffff)
|
|
Section->Header.Characteristics |= COFF::IMAGE_SCN_LNK_NRELOC_OVFL;
|
|
WriteSectionHeader(Section->Header);
|
|
}
|
|
}
|
|
|
|
for (i = Sections.begin(), ie = Sections.end(),
|
|
j = Asm.begin(), je = Asm.end();
|
|
(i != ie) && (j != je); ++i, ++j) {
|
|
|
|
if ((*i)->Number == -1)
|
|
continue;
|
|
|
|
if ((*i)->Header.PointerToRawData != 0) {
|
|
assert(OS.tell() == (*i)->Header.PointerToRawData &&
|
|
"Section::PointerToRawData is insane!");
|
|
|
|
Asm.writeSectionData(j, Layout);
|
|
}
|
|
|
|
if ((*i)->Relocations.size() > 0) {
|
|
assert(OS.tell() == (*i)->Header.PointerToRelocations &&
|
|
"Section::PointerToRelocations is insane!");
|
|
|
|
if ((*i)->Relocations.size() >= 0xffff) {
|
|
// In case of overflow, write actual relocation count as first
|
|
// relocation. Including the synthetic reloc itself (+ 1).
|
|
COFF::relocation r;
|
|
r.VirtualAddress = (*i)->Relocations.size() + 1;
|
|
r.SymbolTableIndex = 0;
|
|
r.Type = 0;
|
|
WriteRelocation(r);
|
|
}
|
|
|
|
for (const auto & Relocation : (*i)->Relocations)
|
|
WriteRelocation(Relocation.Data);
|
|
} else
|
|
assert((*i)->Header.PointerToRelocations == 0 &&
|
|
"Section::PointerToRelocations is insane!");
|
|
}
|
|
}
|
|
|
|
assert(OS.tell() == Header.PointerToSymbolTable &&
|
|
"Header::PointerToSymbolTable is insane!");
|
|
|
|
for (auto & Symbol : Symbols)
|
|
if (Symbol->Index != -1)
|
|
WriteSymbol(*Symbol);
|
|
|
|
OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
|
|
}
|
|
|
|
MCWinCOFFObjectTargetWriter::MCWinCOFFObjectTargetWriter(unsigned Machine_) :
|
|
Machine(Machine_) {
|
|
}
|
|
|
|
// Pin the vtable to this file.
|
|
void MCWinCOFFObjectTargetWriter::anchor() {}
|
|
|
|
//------------------------------------------------------------------------------
|
|
// WinCOFFObjectWriter factory function
|
|
|
|
namespace llvm {
|
|
MCObjectWriter *createWinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
|
|
raw_ostream &OS) {
|
|
return new WinCOFFObjectWriter(MOTW, OS);
|
|
}
|
|
}
|