//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "WinCOFFObjectWriter"
+#include "llvm/MC/MCWinCOFFObjectWriter.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCAsmLayout.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCSectionCOFF.h"
+#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
-#include "llvm/MC/MCAssembler.h"
-#include "llvm/MC/MCAsmLayout.h"
+#include "llvm/Support/COFF.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/TimeValue.h"
+#include <cstdio>
+
using namespace llvm;
+#define DEBUG_TYPE "WinCOFFObjectWriter"
+
namespace {
+typedef SmallString<COFF::NameSize> name;
+
+enum AuxiliaryType {
+ ATFunctionDefinition,
+ ATbfAndefSymbol,
+ ATWeakExternal,
+ ATFile,
+ ATSectionDefinition
+};
+
+struct AuxSymbol {
+ AuxiliaryType AuxType;
+ COFF::Auxiliary Aux;
+};
+
+class COFFSymbol;
+class COFFSection;
+
+class COFFSymbol {
+public:
+ COFF::symbol Data;
+
+ typedef SmallVector<AuxSymbol, 1> AuxiliarySymbols;
+
+ name Name;
+ int Index;
+ AuxiliarySymbols Aux;
+ COFFSymbol *Other;
+ COFFSection *Section;
+ int Relocations;
+
+ MCSymbolData const *MCData;
+
+ COFFSymbol(StringRef name);
+ size_t size() const;
+ void set_name_offset(uint32_t Offset);
+
+ bool should_keep() const;
+};
+
+// This class contains staging data for a COFF relocation entry.
+struct COFFRelocation {
+ COFF::relocation Data;
+ COFFSymbol *Symb;
+
+ COFFRelocation() : Symb(nullptr) {}
+ static size_t size() { return COFF::RelocationSize; }
+};
+
+typedef std::vector<COFFRelocation> relocations;
+
+class COFFSection {
+public:
+ COFF::section Header;
+
+ std::string Name;
+ int Number;
+ MCSectionData const *MCData;
+ COFFSymbol *Symbol;
+ relocations Relocations;
+
+ COFFSection(StringRef name);
+ static size_t size();
+};
+
+// This class holds the COFF string table.
+class StringTable {
+ typedef StringMap<size_t> map;
+ map Map;
+
+ void update_length();
+public:
+ std::vector<char> Data;
+
+ StringTable();
+ size_t size() const;
+ size_t insert(StringRef String);
+};
+
+class WinCOFFObjectWriter : public MCObjectWriter {
+public:
+
+ typedef std::vector<std::unique_ptr<COFFSymbol>> symbols;
+ typedef std::vector<std::unique_ptr<COFFSection>> sections;
+
+ typedef DenseMap<MCSymbol const *, COFFSymbol *> symbol_map;
+ typedef DenseMap<MCSection const *, COFFSection *> section_map;
+
+ std::unique_ptr<MCWinCOFFObjectTargetWriter> TargetObjectWriter;
+
+ // Root level file contents.
+ COFF::header Header;
+ sections Sections;
+ symbols Symbols;
+ StringTable Strings;
+
+ // Maps used during object file creation.
+ section_map SectionMap;
+ symbol_map SymbolMap;
+
+ WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW, raw_ostream &OS);
+
+ COFFSymbol *createSymbol(StringRef Name);
+ COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol * Symbol);
+ COFFSection *createSection(StringRef Name);
+
+ template <typename object_t, typename list_t>
+ object_t *createCOFFEntity(StringRef Name, list_t &List);
+
+ void DefineSection(MCSectionData const &SectionData);
+ void DefineSymbol(MCSymbolData const &SymbolData, MCAssembler &Assembler,
+ const MCAsmLayout &Layout);
+
+ void MakeSymbolReal(COFFSymbol &S, size_t Index);
+ void MakeSectionReal(COFFSection &S, size_t Number);
+
+ bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);
+
+ bool IsPhysicalSection(COFFSection *S);
+
+ // Entity writing methods.
+
+ void WriteFileHeader(const COFF::header &Header);
+ void WriteSymbol(const COFFSymbol &S);
+ void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
+ void WriteSectionHeader(const COFF::section &S);
+ void WriteRelocation(const COFF::relocation &R);
+
+ // MCObjectWriter interface implementation.
+
+ void ExecutePostLayoutBinding(MCAssembler &Asm,
+ const MCAsmLayout &Layout) override;
+
+ void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ const MCFragment *Fragment, const MCFixup &Fixup,
+ MCValue Target, bool &IsPCRel,
+ uint64_t &FixedValue) override;
+
+ void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
+};
+}
+
+static inline void write_uint32_le(void *Data, uint32_t const &Value) {
+ uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
+ Ptr[0] = (Value & 0x000000FF) >> 0;
+ Ptr[1] = (Value & 0x0000FF00) >> 8;
+ Ptr[2] = (Value & 0x00FF0000) >> 16;
+ Ptr[3] = (Value & 0xFF000000) >> 24;
+}
+
+//------------------------------------------------------------------------------
+// Symbol class implementation
+
+COFFSymbol::COFFSymbol(StringRef name)
+ : Name(name.begin(), name.end())
+ , Other(nullptr)
+ , Section(nullptr)
+ , Relocations(0)
+ , MCData(nullptr) {
+ memset(&Data, 0, sizeof(Data));
+}
+
+size_t COFFSymbol::size() const {
+ return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
+}
+
+// In the case that the name does not fit within 8 bytes, the offset
+// into the string table is stored in the last 4 bytes instead, leaving
+// the first 4 bytes as 0.
+void COFFSymbol::set_name_offset(uint32_t Offset) {
+ write_uint32_le(Data.Name + 0, 0);
+ write_uint32_le(Data.Name + 4, Offset);
+}
+
+/// logic to decide if the symbol should be reported in the symbol table
+bool COFFSymbol::should_keep() const {
+ // no section means its external, keep it
+ if (!Section)
+ return true;
+
+ // if it has relocations pointing at it, keep it
+ if (Relocations > 0) {
+ assert(Section->Number != -1 && "Sections with relocations must be real!");
+ return true;
+ }
- class WinCOFFObjectWriter : public MCObjectWriter {
- public:
- WinCOFFObjectWriter(raw_ostream &OS);
+ // if the section its in is being droped, drop it
+ if (Section->Number == -1)
+ return false;
- // MCObjectWriter interface implementation.
+ // if it is the section symbol, keep it
+ if (Section->Symbol == this)
+ return true;
- void ExecutePostLayoutBinding(MCAssembler &Asm);
+ // if its temporary, drop it
+ if (MCData && MCData->getSymbol().isTemporary())
+ return false;
- void RecordRelocation(const MCAssembler &Asm,
- const MCAsmLayout &Layout,
- const MCFragment *Fragment,
- const MCFixup &Fixup,
- MCValue Target,
- uint64_t &FixedValue);
+ // otherwise, keep it
+ return true;
+}
+
+//------------------------------------------------------------------------------
+// Section class implementation
+
+COFFSection::COFFSection(StringRef name)
+ : Name(name)
+ , MCData(nullptr)
+ , Symbol(nullptr) {
+ memset(&Header, 0, sizeof(Header));
+}
+
+size_t COFFSection::size() {
+ return COFF::SectionSize;
+}
+
+//------------------------------------------------------------------------------
+// StringTable class implementation
+
+/// Write the length of the string table into Data.
+/// The length of the string table includes uint32 length header.
+void StringTable::update_length() {
+ write_uint32_le(&Data.front(), Data.size());
+}
+
+StringTable::StringTable() {
+ // The string table data begins with the length of the entire string table
+ // including the length header. Allocate space for this header.
+ Data.resize(4);
+ update_length();
+}
+
+size_t StringTable::size() const {
+ return Data.size();
+}
+
+/// Add String to the table iff it is not already there.
+/// @returns the index into the string table where the string is now located.
+size_t StringTable::insert(StringRef String) {
+ map::iterator i = Map.find(String);
+
+ if (i != Map.end())
+ return i->second;
+
+ size_t Offset = Data.size();
+
+ // Insert string data into string table.
+ Data.insert(Data.end(), String.begin(), String.end());
+ Data.push_back('\0');
+
+ // Put a reference to it in the map.
+ Map[String] = Offset;
+
+ // Update the internal length field.
+ update_length();
+
+ return Offset;
+}
+
+//------------------------------------------------------------------------------
+// WinCOFFObjectWriter class implementation
+
+WinCOFFObjectWriter::WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
+ raw_ostream &OS)
+ : MCObjectWriter(OS, true)
+ , TargetObjectWriter(MOTW) {
+ memset(&Header, 0, sizeof(Header));
+
+ Header.Machine = TargetObjectWriter->getMachine();
+}
+
+COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
+ return createCOFFEntity<COFFSymbol>(Name, Symbols);
+}
- void WriteObject(const MCAssembler &Asm, const MCAsmLayout &Layout);
- };
+COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol * Symbol){
+ symbol_map::iterator i = SymbolMap.find(Symbol);
+ if (i != SymbolMap.end())
+ return i->second;
+ COFFSymbol *RetSymbol
+ = createCOFFEntity<COFFSymbol>(Symbol->getName(), Symbols);
+ SymbolMap[Symbol] = RetSymbol;
+ return RetSymbol;
}
-WinCOFFObjectWriter::WinCOFFObjectWriter(raw_ostream &OS)
- : MCObjectWriter(OS, true) {
+COFFSection *WinCOFFObjectWriter::createSection(StringRef Name) {
+ return createCOFFEntity<COFFSection>(Name, Sections);
+}
+
+/// A template used to lookup or create a symbol/section, and initialize it if
+/// needed.
+template <typename object_t, typename list_t>
+object_t *WinCOFFObjectWriter::createCOFFEntity(StringRef Name,
+ list_t &List) {
+ List.push_back(make_unique<object_t>(Name));
+
+ return List.back().get();
+}
+
+/// This function takes a section data object from the assembler
+/// and creates the associated COFF section staging object.
+void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
+ assert(SectionData.getSection().getVariant() == MCSection::SV_COFF
+ && "Got non-COFF section in the COFF backend!");
+ // FIXME: Not sure how to verify this (at least in a debug build).
+ MCSectionCOFF const &Sec =
+ static_cast<MCSectionCOFF const &>(SectionData.getSection());
+
+ COFFSection *coff_section = createSection(Sec.getSectionName());
+ COFFSymbol *coff_symbol = createSymbol(Sec.getSectionName());
+ if (Sec.getSelection() != COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) {
+ if (const MCSymbol *S = Sec.getCOMDATSymbol()) {
+ COFFSymbol *COMDATSymbol = GetOrCreateCOFFSymbol(S);
+ if (COMDATSymbol->Section)
+ report_fatal_error("two sections have the same comdat");
+ COMDATSymbol->Section = coff_section;
+ }
+ }
+
+ coff_section->Symbol = coff_symbol;
+ coff_symbol->Section = coff_section;
+ coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
+
+ // In this case the auxiliary symbol is a Section Definition.
+ coff_symbol->Aux.resize(1);
+ memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
+ coff_symbol->Aux[0].AuxType = ATSectionDefinition;
+ coff_symbol->Aux[0].Aux.SectionDefinition.Selection = Sec.getSelection();
+
+ coff_section->Header.Characteristics = Sec.getCharacteristics();
+
+ uint32_t &Characteristics = coff_section->Header.Characteristics;
+ switch (SectionData.getAlignment()) {
+ case 1: Characteristics |= COFF::IMAGE_SCN_ALIGN_1BYTES; break;
+ case 2: Characteristics |= COFF::IMAGE_SCN_ALIGN_2BYTES; break;
+ case 4: Characteristics |= COFF::IMAGE_SCN_ALIGN_4BYTES; break;
+ case 8: Characteristics |= COFF::IMAGE_SCN_ALIGN_8BYTES; break;
+ case 16: Characteristics |= COFF::IMAGE_SCN_ALIGN_16BYTES; break;
+ case 32: Characteristics |= COFF::IMAGE_SCN_ALIGN_32BYTES; break;
+ case 64: Characteristics |= COFF::IMAGE_SCN_ALIGN_64BYTES; break;
+ case 128: Characteristics |= COFF::IMAGE_SCN_ALIGN_128BYTES; break;
+ case 256: Characteristics |= COFF::IMAGE_SCN_ALIGN_256BYTES; break;
+ case 512: Characteristics |= COFF::IMAGE_SCN_ALIGN_512BYTES; break;
+ case 1024: Characteristics |= COFF::IMAGE_SCN_ALIGN_1024BYTES; break;
+ case 2048: Characteristics |= COFF::IMAGE_SCN_ALIGN_2048BYTES; break;
+ case 4096: Characteristics |= COFF::IMAGE_SCN_ALIGN_4096BYTES; break;
+ case 8192: Characteristics |= COFF::IMAGE_SCN_ALIGN_8192BYTES; break;
+ default:
+ llvm_unreachable("unsupported section alignment");
+ }
+
+ // Bind internal COFF section to MC section.
+ coff_section->MCData = &SectionData;
+ SectionMap[&SectionData.getSection()] = coff_section;
+}
+
+static uint64_t getSymbolValue(const MCSymbolData &Data,
+ const MCAsmLayout &Layout) {
+ if (Data.isCommon() && Data.isExternal())
+ return Data.getCommonSize();
+
+ uint64_t Res;
+ if (!Layout.getSymbolOffset(&Data, Res))
+ return 0;
+
+ return Res;
+}
+
+/// This function takes a symbol data object from the assembler
+/// and creates the associated COFF symbol staging object.
+void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
+ MCAssembler &Assembler,
+ const MCAsmLayout &Layout) {
+ MCSymbol const &Symbol = SymbolData.getSymbol();
+ COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&Symbol);
+ SymbolMap[&Symbol] = coff_symbol;
+
+ if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
+ coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
+
+ if (Symbol.isVariable()) {
+ const MCSymbolRefExpr *SymRef =
+ dyn_cast<MCSymbolRefExpr>(Symbol.getVariableValue());
+
+ if (!SymRef)
+ report_fatal_error("Weak externals may only alias symbols");
+
+ coff_symbol->Other = GetOrCreateCOFFSymbol(&SymRef->getSymbol());
+ } else {
+ std::string WeakName = std::string(".weak.")
+ + Symbol.getName().str()
+ + ".default";
+ COFFSymbol *WeakDefault = createSymbol(WeakName);
+ WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
+ WeakDefault->Data.StorageClass = COFF::IMAGE_SYM_CLASS_EXTERNAL;
+ WeakDefault->Data.Type = 0;
+ WeakDefault->Data.Value = 0;
+ coff_symbol->Other = WeakDefault;
+ }
+
+ // Setup the Weak External auxiliary symbol.
+ coff_symbol->Aux.resize(1);
+ memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
+ coff_symbol->Aux[0].AuxType = ATWeakExternal;
+ coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
+ coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
+ COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
+
+ coff_symbol->MCData = &SymbolData;
+ } else {
+ const MCSymbolData &ResSymData = Assembler.getSymbolData(Symbol);
+ const MCSymbol *Base = Layout.getBaseSymbol(Symbol);
+ coff_symbol->Data.Value = getSymbolValue(ResSymData, Layout);
+
+ coff_symbol->Data.Type = (ResSymData.getFlags() & 0x0000FFFF) >> 0;
+ coff_symbol->Data.StorageClass = (ResSymData.getFlags() & 0x00FF0000) >> 16;
+
+ // If no storage class was specified in the streamer, define it here.
+ if (coff_symbol->Data.StorageClass == 0) {
+ bool external = ResSymData.isExternal() || !ResSymData.Fragment;
+
+ coff_symbol->Data.StorageClass =
+ external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
+ }
+
+ if (!Base) {
+ coff_symbol->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
+ } else {
+ const MCSymbolData &BaseData = Assembler.getSymbolData(*Base);
+ if (BaseData.Fragment) {
+ COFFSection *Sec =
+ SectionMap[&BaseData.Fragment->getParent()->getSection()];
+
+ if (coff_symbol->Section && coff_symbol->Section != Sec)
+ report_fatal_error("conflicting sections for symbol");
+
+ coff_symbol->Section = Sec;
+ }
+ }
+
+ coff_symbol->MCData = &ResSymData;
+ }
+}
+
+// Maximum offsets for different string table entry encodings.
+static const unsigned Max6DecimalOffset = 999999;
+static const unsigned Max7DecimalOffset = 9999999;
+static const uint64_t MaxBase64Offset = 0xFFFFFFFFFULL; // 64^6, including 0
+
+// Encode a string table entry offset in base 64, padded to 6 chars, and
+// prefixed with a double slash: '//AAAAAA', '//AAAAAB', ...
+// Buffer must be at least 8 bytes large. No terminating null appended.
+static void encodeBase64StringEntry(char* Buffer, uint64_t Value) {
+ assert(Value > Max7DecimalOffset && Value <= MaxBase64Offset &&
+ "Illegal section name encoding for value");
+
+ static const char Alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ "abcdefghijklmnopqrstuvwxyz"
+ "0123456789+/";
+
+ Buffer[0] = '/';
+ Buffer[1] = '/';
+
+ char* Ptr = Buffer + 7;
+ for (unsigned i = 0; i < 6; ++i) {
+ unsigned Rem = Value % 64;
+ Value /= 64;
+ *(Ptr--) = Alphabet[Rem];
+ }
+}
+
+/// making a section real involves assigned it a number and putting
+/// name into the string table if needed
+void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
+ 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) {
+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 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. Empirical 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;
+ }
+ }
+
+ if (TargetObjectWriter->recordRelocation(Fixup))
+ coff_section->Relocations.push_back(Reloc);
}
-void WinCOFFObjectWriter::WriteObject(const MCAssembler &Asm,
+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) {
+ size_t Number = ++Header.NumberOfSections;
+ SectionIndices[Section.get()] = Number;
+ MakeSectionReal(*Section, Number);
+ }
+
+ 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());
+
+ const MCSymbol *COMDAT = MCSec.getCOMDATSymbol();
+ assert(COMDAT);
+ COFFSymbol *COMDATSymbol = GetOrCreateCOFFSymbol(COMDAT);
+ assert(COMDATSymbol);
+ COFFSection *Assoc = COMDATSymbol->Section;
+ if (!Assoc)
+ report_fatal_error(
+ Twine("Missing associated COMDAT section 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(raw_ostream &OS) {
- return new WinCOFFObjectWriter(OS);
+ MCObjectWriter *createWinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
+ raw_ostream &OS) {
+ return new WinCOFFObjectWriter(MOTW, OS);
}
}
projects / oota-llvm.git / blobdiff