2010-08-17 02:57:57 +08:00
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//===- lib/MC/ELFObjectWriter.cpp - 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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#include "llvm/MC/ELFObjectWriter.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCAsmLayout.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCELFSymbolFlags.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/MCSectionELF.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/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/ELF.h"
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#include "llvm/Target/TargetAsmBackend.h"
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#include "../Target/X86/X86FixupKinds.h"
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#include <vector>
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using namespace llvm;
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2010-09-18 23:03:21 +08:00
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static unsigned GetType(const MCSymbolData &SD) {
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uint32_t Type = (SD.getFlags() & (0xf << ELF_STT_Shift)) >> ELF_STT_Shift;
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assert(Type == ELF::STT_NOTYPE || Type == ELF::STT_OBJECT ||
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Type == ELF::STT_FUNC || Type == ELF::STT_SECTION ||
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Type == ELF::STT_FILE || Type == ELF::STT_COMMON ||
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Type == ELF::STT_TLS);
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return Type;
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}
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2010-09-24 03:55:14 +08:00
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static unsigned GetBinding(const MCSymbolData &SD) {
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uint32_t Binding = (SD.getFlags() & (0xf << ELF_STB_Shift)) >> ELF_STB_Shift;
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assert(Binding == ELF::STB_LOCAL || Binding == ELF::STB_GLOBAL ||
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Binding == ELF::STB_WEAK);
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return Binding;
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}
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static void SetBinding(MCSymbolData &SD, unsigned Binding) {
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assert(Binding == ELF::STB_LOCAL || Binding == ELF::STB_GLOBAL ||
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Binding == ELF::STB_WEAK);
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uint32_t OtherFlags = SD.getFlags() & ~(0xf << ELF_STB_Shift);
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SD.setFlags(OtherFlags | (Binding << ELF_STB_Shift));
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}
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2010-08-17 02:57:57 +08:00
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namespace {
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class ELFObjectWriterImpl {
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static bool isFixupKindX86PCRel(unsigned Kind) {
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switch (Kind) {
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default:
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return false;
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case X86::reloc_pcrel_1byte:
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case X86::reloc_pcrel_4byte:
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case X86::reloc_riprel_4byte:
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case X86::reloc_riprel_4byte_movq_load:
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return true;
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}
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}
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2010-08-28 11:21:03 +08:00
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/*static bool isFixupKindX86RIPRel(unsigned Kind) {
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2010-08-17 02:57:57 +08:00
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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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2010-08-28 11:21:03 +08:00
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}*/
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2010-08-17 02:57:57 +08:00
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/// ELFSymbolData - Helper struct for containing some precomputed information
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/// 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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2010-09-18 23:03:21 +08:00
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if (GetType(*SymbolData) == ELF::STT_FILE)
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return true;
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if (GetType(*RHS.SymbolData) == ELF::STT_FILE)
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return false;
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2010-08-24 05:23:52 +08:00
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return SymbolData->getSymbol().getName() <
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RHS.SymbolData->getSymbol().getName();
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2010-08-17 02:57:57 +08:00
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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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uint64_t r_info;
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uint64_t r_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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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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ELFObjectWriter *Writer;
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raw_ostream &OS;
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unsigned Is64Bit : 1;
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bool HasRelocationAddend;
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2010-09-10 01:57:50 +08:00
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Triple::OSType OSType;
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2010-08-17 02:57:57 +08:00
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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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unsigned ShstrtabIndex;
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public:
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ELFObjectWriterImpl(ELFObjectWriter *_Writer, bool _Is64Bit,
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2010-09-10 01:57:50 +08:00
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bool _HasRelAddend, Triple::OSType _OSType)
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2010-09-07 00:11:52 +08:00
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: Writer(_Writer), OS(Writer->getStream()),
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2010-09-10 01:57:50 +08:00
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Is64Bit(_Is64Bit), HasRelocationAddend(_HasRelAddend),
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OSType(_OSType) {
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2010-08-17 02:57:57 +08:00
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}
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void Write8(uint8_t Value) { Writer->Write8(Value); }
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void Write16(uint16_t Value) { Writer->Write16(Value); }
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void Write32(uint32_t Value) { Writer->Write32(Value); }
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2010-08-28 11:21:03 +08:00
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//void Write64(uint64_t Value) { Writer->Write64(Value); }
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2010-08-17 02:57:57 +08:00
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void WriteZeros(unsigned N) { Writer->WriteZeros(N); }
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2010-08-28 11:21:03 +08:00
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//void WriteBytes(StringRef Str, unsigned ZeroFillSize = 0) {
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// Writer->WriteBytes(Str, ZeroFillSize);
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//}
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2010-08-17 02:57:57 +08:00
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void WriteWord(uint64_t W) {
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2010-08-28 11:21:03 +08:00
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if (Is64Bit)
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2010-08-17 02:57:57 +08:00
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Writer->Write64(W);
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2010-08-28 11:21:03 +08:00
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else
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2010-08-17 02:57:57 +08:00
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Writer->Write32(W);
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}
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void String8(char *buf, uint8_t Value) {
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buf[0] = Value;
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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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2010-08-24 05:23:52 +08:00
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StringLE16(buf, uint16_t(Value >> 0));
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2010-08-24 05:32:00 +08:00
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StringLE16(buf + 2, uint16_t(Value >> 16));
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2010-08-17 02:57:57 +08:00
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}
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void StringLE64(char *buf, uint64_t Value) {
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2010-08-24 05:23:52 +08:00
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StringLE32(buf, uint32_t(Value >> 0));
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2010-08-24 05:32:00 +08:00
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StringLE32(buf + 4, uint32_t(Value >> 32));
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2010-08-17 02:57:57 +08:00
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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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2010-08-24 05:23:52 +08:00
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StringBE16(buf, uint16_t(Value >> 16));
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2010-08-24 05:32:00 +08:00
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StringBE16(buf + 2, uint16_t(Value >> 0));
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2010-08-17 02:57:57 +08:00
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}
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void StringBE64(char *buf, uint64_t Value) {
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2010-08-24 05:23:52 +08:00
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StringBE32(buf, uint32_t(Value >> 32));
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2010-08-24 05:32:00 +08:00
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StringBE32(buf + 4, uint32_t(Value >> 0));
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2010-08-17 02:57:57 +08:00
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}
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void String16(char *buf, uint16_t Value) {
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if (Writer->isLittleEndian())
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2010-08-17 03:15:06 +08:00
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StringLE16(buf, Value);
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2010-08-17 02:57:57 +08:00
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else
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2010-08-17 03:15:06 +08:00
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StringBE16(buf, Value);
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2010-08-17 02:57:57 +08:00
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}
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void String32(char *buf, uint32_t Value) {
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if (Writer->isLittleEndian())
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2010-08-17 03:15:06 +08:00
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StringLE32(buf, Value);
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2010-08-17 02:57:57 +08:00
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else
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2010-08-17 03:15:06 +08:00
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StringBE32(buf, Value);
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2010-08-17 02:57:57 +08:00
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}
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void String64(char *buf, uint64_t Value) {
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if (Writer->isLittleEndian())
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2010-08-17 03:15:06 +08:00
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StringLE64(buf, Value);
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2010-08-17 02:57:57 +08:00
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else
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2010-08-17 03:15:06 +08:00
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StringBE64(buf, Value);
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2010-08-17 02:57:57 +08:00
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}
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void WriteHeader(uint64_t SectionDataSize, unsigned NumberOfSections);
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void WriteSymbolEntry(MCDataFragment *F, uint64_t name, uint8_t info,
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uint64_t value, uint64_t size,
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uint8_t other, uint16_t shndx);
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void WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD,
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const MCAsmLayout &Layout);
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void WriteSymbolTable(MCDataFragment *F, const MCAssembler &Asm,
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2010-09-17 03:46:31 +08:00
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const MCAsmLayout &Layout,
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unsigned NumRegularSections);
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2010-08-17 02:57:57 +08:00
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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, uint64_t &FixedValue);
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2010-08-24 05:19:37 +08:00
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uint64_t getSymbolIndexInSymbolTable(const MCAssembler &Asm,
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const MCSymbol *S);
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2010-08-17 02:57:57 +08:00
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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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void ComputeSymbolTable(MCAssembler &Asm);
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void WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
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const MCSectionData &SD);
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void WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout) {
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for (MCAssembler::const_iterator it = Asm.begin(),
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ie = Asm.end(); it != ie; ++it) {
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WriteRelocation(Asm, Layout, *it);
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}
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}
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void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout);
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2010-08-24 05:19:37 +08:00
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void ExecutePostLayoutBinding(MCAssembler &Asm) {
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// Compute symbol table information.
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ComputeSymbolTable(Asm);
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}
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2010-08-17 02:57:57 +08:00
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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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void WriteRelocationsFragment(const MCAssembler &Asm, MCDataFragment *F,
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const MCSectionData *SD);
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void WriteObject(const MCAssembler &Asm, const MCAsmLayout &Layout);
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};
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}
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// Emit the ELF header.
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void ELFObjectWriterImpl::WriteHeader(uint64_t SectionDataSize,
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unsigned NumberOfSections) {
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// ELF Header
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// ----------
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//
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// Note
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// ----
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// emitWord method behaves differently for ELF32 and ELF64, writing
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// 4 bytes in the former and 8 in the latter.
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Write8(0x7f); // e_ident[EI_MAG0]
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Write8('E'); // e_ident[EI_MAG1]
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Write8('L'); // e_ident[EI_MAG2]
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Write8('F'); // e_ident[EI_MAG3]
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Write8(Is64Bit ? ELF::ELFCLASS64 : ELF::ELFCLASS32); // e_ident[EI_CLASS]
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// e_ident[EI_DATA]
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Write8(Writer->isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
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Write8(ELF::EV_CURRENT); // e_ident[EI_VERSION]
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2010-09-10 01:57:50 +08:00
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// e_ident[EI_OSABI]
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switch (OSType) {
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case Triple::FreeBSD: Write8(ELF::ELFOSABI_FREEBSD); break;
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case Triple::Linux: Write8(ELF::ELFOSABI_LINUX); break;
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default: Write8(ELF::ELFOSABI_NONE); break;
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}
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2010-08-17 02:57:57 +08:00
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Write8(0); // e_ident[EI_ABIVERSION]
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WriteZeros(ELF::EI_NIDENT - ELF::EI_PAD);
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Write16(ELF::ET_REL); // e_type
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// FIXME: Make this configurable
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2010-08-18 01:02:29 +08:00
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Write16(Is64Bit ? ELF::EM_X86_64 : ELF::EM_386); // e_machine = target
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2010-08-17 02:57:57 +08:00
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Write32(ELF::EV_CURRENT); // e_version
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WriteWord(0); // e_entry, no entry point in .o file
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WriteWord(0); // e_phoff, no program header for .o
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2010-08-18 01:02:29 +08:00
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WriteWord(SectionDataSize + (Is64Bit ? sizeof(ELF::Elf64_Ehdr) :
|
|
|
|
sizeof(ELF::Elf32_Ehdr))); // e_shoff = sec hdr table off in bytes
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
// FIXME: Make this configurable.
|
|
|
|
Write32(0); // e_flags = whatever the target wants
|
|
|
|
|
|
|
|
// e_ehsize = ELF header size
|
|
|
|
Write16(Is64Bit ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
|
|
|
|
|
|
|
|
Write16(0); // e_phentsize = prog header entry size
|
|
|
|
Write16(0); // e_phnum = # prog header entries = 0
|
|
|
|
|
|
|
|
// e_shentsize = Section header entry size
|
|
|
|
Write16(Is64Bit ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr));
|
|
|
|
|
|
|
|
// e_shnum = # of section header ents
|
|
|
|
Write16(NumberOfSections);
|
|
|
|
|
|
|
|
// e_shstrndx = Section # of '.shstrtab'
|
|
|
|
Write16(ShstrtabIndex);
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriterImpl::WriteSymbolEntry(MCDataFragment *F, uint64_t name,
|
|
|
|
uint8_t info, uint64_t value,
|
|
|
|
uint64_t size, uint8_t other,
|
|
|
|
uint16_t shndx) {
|
|
|
|
if (Is64Bit) {
|
|
|
|
char buf[8];
|
|
|
|
|
|
|
|
String32(buf, name);
|
|
|
|
F->getContents() += StringRef(buf, 4); // st_name
|
|
|
|
|
|
|
|
String8(buf, info);
|
|
|
|
F->getContents() += StringRef(buf, 1); // st_info
|
2010-08-17 08:00:46 +08:00
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
String8(buf, other);
|
|
|
|
F->getContents() += StringRef(buf, 1); // st_other
|
|
|
|
|
|
|
|
String16(buf, shndx);
|
|
|
|
F->getContents() += StringRef(buf, 2); // st_shndx
|
|
|
|
|
|
|
|
String64(buf, value);
|
|
|
|
F->getContents() += StringRef(buf, 8); // st_value
|
|
|
|
|
|
|
|
String64(buf, size);
|
|
|
|
F->getContents() += StringRef(buf, 8); // st_size
|
|
|
|
} else {
|
|
|
|
char buf[4];
|
|
|
|
|
|
|
|
String32(buf, name);
|
|
|
|
F->getContents() += StringRef(buf, 4); // st_name
|
|
|
|
|
|
|
|
String32(buf, value);
|
|
|
|
F->getContents() += StringRef(buf, 4); // st_value
|
|
|
|
|
|
|
|
String32(buf, size);
|
|
|
|
F->getContents() += StringRef(buf, 4); // st_size
|
|
|
|
|
|
|
|
String8(buf, info);
|
|
|
|
F->getContents() += StringRef(buf, 1); // st_info
|
|
|
|
|
|
|
|
String8(buf, other);
|
|
|
|
F->getContents() += StringRef(buf, 1); // st_other
|
|
|
|
|
|
|
|
String16(buf, shndx);
|
|
|
|
F->getContents() += StringRef(buf, 2); // st_shndx
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2010-09-28 05:23:02 +08:00
|
|
|
static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout) {
|
|
|
|
if (Data.isCommon() && Data.isExternal())
|
|
|
|
return Data.getCommonAlignment();
|
|
|
|
|
|
|
|
const MCSymbol &Symbol = Data.getSymbol();
|
|
|
|
if (!Symbol.isInSection())
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
if (!Data.isCommon() && !(Data.getFlags() & ELF_STB_Weak))
|
|
|
|
if (MCFragment *FF = Data.getFragment())
|
|
|
|
return Layout.getSymbolAddress(&Data) -
|
|
|
|
Layout.getSectionAddress(FF->getParent());
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
void ELFObjectWriterImpl::WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD,
|
|
|
|
const MCAsmLayout &Layout) {
|
|
|
|
MCSymbolData &Data = *MSD.SymbolData;
|
|
|
|
uint8_t Info = (Data.getFlags() & 0xff);
|
|
|
|
uint8_t Other = ((Data.getFlags() & 0xf00) >> ELF_STV_Shift);
|
2010-09-28 05:23:02 +08:00
|
|
|
uint64_t Value = SymbolValue(Data, Layout);
|
2010-08-17 02:57:57 +08:00
|
|
|
uint64_t Size = 0;
|
|
|
|
const MCExpr *ESize;
|
|
|
|
|
2010-09-21 08:24:38 +08:00
|
|
|
assert(!(Data.isCommon() && !Data.isExternal()));
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
ESize = Data.getSize();
|
|
|
|
if (Data.getSize()) {
|
|
|
|
MCValue Res;
|
|
|
|
if (ESize->getKind() == MCExpr::Binary) {
|
|
|
|
const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(ESize);
|
|
|
|
|
|
|
|
if (BE->EvaluateAsRelocatable(Res, &Layout)) {
|
|
|
|
MCSymbolData &A =
|
|
|
|
Layout.getAssembler().getSymbolData(Res.getSymA()->getSymbol());
|
|
|
|
MCSymbolData &B =
|
|
|
|
Layout.getAssembler().getSymbolData(Res.getSymB()->getSymbol());
|
|
|
|
|
|
|
|
Size = Layout.getSymbolAddress(&A) - Layout.getSymbolAddress(&B);
|
|
|
|
}
|
|
|
|
} else if (ESize->getKind() == MCExpr::Constant) {
|
2010-08-17 08:00:46 +08:00
|
|
|
Size = static_cast<const MCConstantExpr *>(ESize)->getValue();
|
2010-08-17 02:57:57 +08:00
|
|
|
} else {
|
|
|
|
assert(0 && "Unsupported size expression");
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// Write out the symbol table entry
|
|
|
|
WriteSymbolEntry(F, MSD.StringIndex, Info, Value,
|
|
|
|
Size, Other, MSD.SectionIndex);
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriterImpl::WriteSymbolTable(MCDataFragment *F,
|
|
|
|
const MCAssembler &Asm,
|
2010-09-17 03:46:31 +08:00
|
|
|
const MCAsmLayout &Layout,
|
|
|
|
unsigned NumRegularSections) {
|
2010-08-17 02:57:57 +08:00
|
|
|
// The string table must be emitted first because we need the index
|
|
|
|
// into the string table for all the symbol names.
|
|
|
|
assert(StringTable.size() && "Missing string table");
|
|
|
|
|
|
|
|
// FIXME: Make sure the start of the symbol table is aligned.
|
|
|
|
|
|
|
|
// The first entry is the undefined symbol entry.
|
|
|
|
unsigned EntrySize = Is64Bit ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
|
2010-08-17 08:00:46 +08:00
|
|
|
F->getContents().append(EntrySize, '\x00');
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
// Write the symbol table entries.
|
|
|
|
LastLocalSymbolIndex = LocalSymbolData.size() + 1;
|
|
|
|
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
|
|
|
|
ELFSymbolData &MSD = LocalSymbolData[i];
|
|
|
|
WriteSymbol(F, MSD, Layout);
|
|
|
|
}
|
|
|
|
|
2010-09-17 03:46:31 +08:00
|
|
|
// Write out a symbol table entry for each regular section.
|
2010-08-17 05:17:09 +08:00
|
|
|
unsigned Index = 1;
|
2010-09-17 03:46:31 +08:00
|
|
|
for (MCAssembler::const_iterator it = Asm.begin();
|
|
|
|
Index <= NumRegularSections; ++it, ++Index) {
|
2010-08-17 05:17:09 +08:00
|
|
|
const MCSectionELF &Section =
|
2010-08-17 08:00:46 +08:00
|
|
|
static_cast<const MCSectionELF&>(it->getSection());
|
2010-08-17 05:17:09 +08:00
|
|
|
// Leave out relocations so we don't have indexes within
|
|
|
|
// the relocations messed up
|
2010-08-18 01:30:07 +08:00
|
|
|
if (Section.getType() == ELF::SHT_RELA || Section.getType() == ELF::SHT_REL)
|
2010-08-17 05:17:09 +08:00
|
|
|
continue;
|
2010-08-17 02:57:57 +08:00
|
|
|
WriteSymbolEntry(F, 0, ELF::STT_SECTION, 0, 0, ELF::STV_DEFAULT, Index);
|
2010-08-17 05:17:09 +08:00
|
|
|
LastLocalSymbolIndex++;
|
|
|
|
}
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
|
|
|
|
ELFSymbolData &MSD = ExternalSymbolData[i];
|
|
|
|
MCSymbolData &Data = *MSD.SymbolData;
|
|
|
|
assert((Data.getFlags() & ELF_STB_Global) &&
|
|
|
|
"External symbol requires STB_GLOBAL flag");
|
|
|
|
WriteSymbol(F, MSD, Layout);
|
2010-09-24 03:55:14 +08:00
|
|
|
if (GetBinding(Data) == ELF::STB_LOCAL)
|
2010-08-17 02:57:57 +08:00
|
|
|
LastLocalSymbolIndex++;
|
|
|
|
}
|
|
|
|
|
|
|
|
for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
|
|
|
|
ELFSymbolData &MSD = UndefinedSymbolData[i];
|
|
|
|
MCSymbolData &Data = *MSD.SymbolData;
|
|
|
|
WriteSymbol(F, MSD, Layout);
|
2010-09-24 03:55:14 +08:00
|
|
|
if (GetBinding(Data) == ELF::STB_LOCAL)
|
2010-08-17 02:57:57 +08:00
|
|
|
LastLocalSymbolIndex++;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2010-09-25 13:42:19 +08:00
|
|
|
static const MCSymbolData *getAtom(const MCSymbolData &SD) {
|
|
|
|
if (!SD.getFragment())
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
return SD.getFragment()->getAtom();
|
|
|
|
}
|
|
|
|
|
2010-08-18 02:20:28 +08:00
|
|
|
// FIXME: this is currently X86/X86_64 only
|
2010-08-17 02:57:57 +08:00
|
|
|
void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm,
|
|
|
|
const MCAsmLayout &Layout,
|
|
|
|
const MCFragment *Fragment,
|
|
|
|
const MCFixup &Fixup,
|
|
|
|
MCValue Target,
|
|
|
|
uint64_t &FixedValue) {
|
|
|
|
int64_t Addend = 0;
|
|
|
|
unsigned Index = 0;
|
2010-08-27 18:38:39 +08:00
|
|
|
int64_t Value = Target.getConstant();
|
2010-08-17 02:57:57 +08:00
|
|
|
|
2010-09-18 06:34:41 +08:00
|
|
|
bool IsPCRel = isFixupKindX86PCRel(Fixup.getKind());
|
2010-08-18 03:45:05 +08:00
|
|
|
if (!Target.isAbsolute()) {
|
2010-08-17 02:57:57 +08:00
|
|
|
const MCSymbol *Symbol = &Target.getSymA()->getSymbol();
|
|
|
|
MCSymbolData &SD = Asm.getSymbolData(*Symbol);
|
2010-09-25 13:42:19 +08:00
|
|
|
const MCSymbolData *Base = getAtom(SD);
|
2010-08-27 01:23:02 +08:00
|
|
|
MCFragment *F = SD.getFragment();
|
2010-08-17 02:57:57 +08:00
|
|
|
|
2010-09-18 06:34:41 +08:00
|
|
|
// Avoid relocations for cases like jumps and calls in the same file.
|
|
|
|
if (Symbol->isDefined() && !SD.isExternal() &&
|
|
|
|
IsPCRel &&
|
|
|
|
&Fragment->getParent()->getSection() == &Symbol->getSection()) {
|
|
|
|
uint64_t FixupAddr = Layout.getFragmentAddress(Fragment) + Fixup.getOffset();
|
|
|
|
FixedValue = Layout.getSymbolAddress(&SD) + Target.getConstant() - FixupAddr;
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
if (Base) {
|
2010-09-25 13:42:19 +08:00
|
|
|
if (Base != &SD) {
|
2010-08-24 05:19:37 +08:00
|
|
|
Index = F->getParent()->getOrdinal() + LocalSymbolData.size() + 1;
|
2010-09-25 05:19:03 +08:00
|
|
|
|
|
|
|
MCSectionData *FSD = F->getParent();
|
|
|
|
// Offset of the symbol in the section
|
|
|
|
Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
|
2010-08-24 03:05:46 +08:00
|
|
|
} else
|
2010-08-24 05:19:37 +08:00
|
|
|
Index = getSymbolIndexInSymbolTable(Asm, Symbol);
|
2010-08-17 02:57:57 +08:00
|
|
|
Addend = Value;
|
2010-08-27 01:23:02 +08:00
|
|
|
// Compensate for the addend on i386.
|
2010-08-27 02:12:04 +08:00
|
|
|
if (Is64Bit)
|
|
|
|
Value = 0;
|
2010-08-17 02:57:57 +08:00
|
|
|
} else {
|
|
|
|
if (F) {
|
|
|
|
// Index of the section in .symtab against this symbol
|
|
|
|
// is being relocated + 2 (empty section + abs. symbols).
|
2010-08-24 05:19:37 +08:00
|
|
|
Index = F->getParent()->getOrdinal() + LocalSymbolData.size() + 1;
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
MCSectionData *FSD = F->getParent();
|
|
|
|
// Offset of the symbol in the section
|
2010-09-25 13:42:19 +08:00
|
|
|
Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
|
2010-08-17 02:57:57 +08:00
|
|
|
} else {
|
2010-09-25 13:42:19 +08:00
|
|
|
Index = getSymbolIndexInSymbolTable(Asm, Symbol);
|
2010-08-17 02:57:57 +08:00
|
|
|
}
|
2010-09-25 13:42:19 +08:00
|
|
|
Addend = Value;
|
|
|
|
// Compensate for the addend on i386.
|
|
|
|
if (Is64Bit)
|
|
|
|
Value = 0;
|
2010-08-17 02:57:57 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2010-08-27 18:38:39 +08:00
|
|
|
FixedValue = Value;
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
// determine the type of the relocation
|
2010-08-27 01:23:02 +08:00
|
|
|
unsigned Type;
|
2010-08-18 02:20:28 +08:00
|
|
|
if (Is64Bit) {
|
|
|
|
if (IsPCRel) {
|
|
|
|
Type = ELF::R_X86_64_PC32;
|
|
|
|
} else {
|
|
|
|
switch ((unsigned)Fixup.getKind()) {
|
|
|
|
default: llvm_unreachable("invalid fixup kind!");
|
|
|
|
case FK_Data_8: Type = ELF::R_X86_64_64; break;
|
|
|
|
case X86::reloc_pcrel_4byte:
|
|
|
|
case FK_Data_4:
|
|
|
|
// check that the offset fits within a signed long
|
2010-09-21 03:20:47 +08:00
|
|
|
if (Target.getConstant() < 0) {
|
|
|
|
assert(isInt<32>(Target.getConstant()));
|
2010-08-18 02:20:28 +08:00
|
|
|
Type = ELF::R_X86_64_32S;
|
2010-09-21 03:20:47 +08:00
|
|
|
} else {
|
|
|
|
assert(isUInt<32>(Target.getConstant()));
|
2010-08-18 02:20:28 +08:00
|
|
|
Type = ELF::R_X86_64_32;
|
2010-09-21 03:20:47 +08:00
|
|
|
}
|
2010-08-18 02:20:28 +08:00
|
|
|
break;
|
|
|
|
case FK_Data_2: Type = ELF::R_X86_64_16; break;
|
|
|
|
case X86::reloc_pcrel_1byte:
|
|
|
|
case FK_Data_1: Type = ELF::R_X86_64_8; break;
|
|
|
|
}
|
|
|
|
}
|
2010-08-17 02:57:57 +08:00
|
|
|
} else {
|
2010-08-18 02:20:28 +08:00
|
|
|
if (IsPCRel) {
|
|
|
|
Type = ELF::R_386_PC32;
|
|
|
|
} else {
|
|
|
|
switch ((unsigned)Fixup.getKind()) {
|
|
|
|
default: llvm_unreachable("invalid fixup kind!");
|
|
|
|
case X86::reloc_pcrel_4byte:
|
|
|
|
case FK_Data_4: Type = ELF::R_386_32; break;
|
|
|
|
case FK_Data_2: Type = ELF::R_386_16; break;
|
|
|
|
case X86::reloc_pcrel_1byte:
|
|
|
|
case FK_Data_1: Type = ELF::R_386_8; break;
|
|
|
|
}
|
2010-08-17 02:57:57 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2010-08-18 02:20:28 +08:00
|
|
|
ELFRelocationEntry ERE;
|
|
|
|
|
|
|
|
if (Is64Bit) {
|
|
|
|
struct ELF::Elf64_Rela ERE64;
|
|
|
|
ERE64.setSymbolAndType(Index, Type);
|
|
|
|
ERE.r_info = ERE64.r_info;
|
|
|
|
} else {
|
|
|
|
struct ELF::Elf32_Rela ERE32;
|
|
|
|
ERE32.setSymbolAndType(Index, Type);
|
|
|
|
ERE.r_info = ERE32.r_info;
|
|
|
|
}
|
2010-08-17 02:57:57 +08:00
|
|
|
|
2010-08-27 01:23:02 +08:00
|
|
|
ERE.r_offset = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
|
2010-08-18 02:20:28 +08:00
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
if (HasRelocationAddend)
|
|
|
|
ERE.r_addend = Addend;
|
2010-08-17 08:33:24 +08:00
|
|
|
else
|
|
|
|
ERE.r_addend = 0; // Silence compiler warning.
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
Relocations[Fragment->getParent()].push_back(ERE);
|
|
|
|
}
|
|
|
|
|
2010-08-24 05:19:37 +08:00
|
|
|
uint64_t
|
|
|
|
ELFObjectWriterImpl::getSymbolIndexInSymbolTable(const MCAssembler &Asm,
|
|
|
|
const MCSymbol *S) {
|
2010-08-26 04:09:43 +08:00
|
|
|
MCSymbolData &SD = Asm.getSymbolData(*S);
|
|
|
|
|
|
|
|
// Local symbol.
|
|
|
|
if (!SD.isExternal() && !S->isUndefined())
|
|
|
|
return SD.getIndex() + /* empty symbol */ 1;
|
|
|
|
|
|
|
|
// External or undefined symbol.
|
|
|
|
return SD.getIndex() + Asm.size() + /* empty symbol */ 1;
|
2010-08-17 02:57:57 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
|
|
|
|
// Build section lookup table.
|
|
|
|
DenseMap<const MCSection*, uint8_t> SectionIndexMap;
|
|
|
|
unsigned Index = 1;
|
|
|
|
for (MCAssembler::iterator it = Asm.begin(),
|
|
|
|
ie = Asm.end(); it != ie; ++it, ++Index)
|
|
|
|
SectionIndexMap[&it->getSection()] = Index;
|
|
|
|
|
|
|
|
// Index 0 is always the empty string.
|
|
|
|
StringMap<uint64_t> StringIndexMap;
|
|
|
|
StringTable += '\x00';
|
|
|
|
|
|
|
|
// Add the data for local symbols.
|
|
|
|
for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
|
|
|
|
ie = Asm.symbol_end(); it != ie; ++it) {
|
|
|
|
const MCSymbol &Symbol = it->getSymbol();
|
|
|
|
|
|
|
|
// Ignore non-linker visible symbols.
|
|
|
|
if (!Asm.isSymbolLinkerVisible(Symbol))
|
|
|
|
continue;
|
|
|
|
|
|
|
|
if (it->isExternal() || Symbol.isUndefined())
|
|
|
|
continue;
|
|
|
|
|
|
|
|
uint64_t &Entry = StringIndexMap[Symbol.getName()];
|
|
|
|
if (!Entry) {
|
|
|
|
Entry = StringTable.size();
|
|
|
|
StringTable += Symbol.getName();
|
|
|
|
StringTable += '\x00';
|
|
|
|
}
|
|
|
|
|
|
|
|
ELFSymbolData MSD;
|
|
|
|
MSD.SymbolData = it;
|
|
|
|
MSD.StringIndex = Entry;
|
|
|
|
|
|
|
|
if (Symbol.isAbsolute()) {
|
|
|
|
MSD.SectionIndex = ELF::SHN_ABS;
|
|
|
|
LocalSymbolData.push_back(MSD);
|
|
|
|
} else {
|
|
|
|
MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
|
|
|
|
assert(MSD.SectionIndex && "Invalid section index!");
|
|
|
|
LocalSymbolData.push_back(MSD);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// Now add non-local symbols.
|
|
|
|
for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
|
|
|
|
ie = Asm.symbol_end(); it != ie; ++it) {
|
|
|
|
const MCSymbol &Symbol = it->getSymbol();
|
|
|
|
|
|
|
|
// Ignore non-linker visible symbols.
|
2010-09-29 00:19:11 +08:00
|
|
|
if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
|
2010-08-17 02:57:57 +08:00
|
|
|
continue;
|
|
|
|
|
|
|
|
if (!it->isExternal() && !Symbol.isUndefined())
|
|
|
|
continue;
|
|
|
|
|
2010-09-29 00:19:11 +08:00
|
|
|
if (Symbol.isVariable())
|
|
|
|
continue;
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
uint64_t &Entry = StringIndexMap[Symbol.getName()];
|
|
|
|
if (!Entry) {
|
|
|
|
Entry = StringTable.size();
|
|
|
|
StringTable += Symbol.getName();
|
|
|
|
StringTable += '\x00';
|
|
|
|
}
|
|
|
|
|
|
|
|
ELFSymbolData MSD;
|
|
|
|
MSD.SymbolData = it;
|
|
|
|
MSD.StringIndex = Entry;
|
|
|
|
|
2010-09-21 08:24:38 +08:00
|
|
|
if (it->isCommon()) {
|
|
|
|
MSD.SectionIndex = ELF::SHN_COMMON;
|
|
|
|
ExternalSymbolData.push_back(MSD);
|
|
|
|
} else if (Symbol.isUndefined()) {
|
2010-08-17 02:57:57 +08:00
|
|
|
MSD.SectionIndex = ELF::SHN_UNDEF;
|
2010-09-24 03:55:14 +08:00
|
|
|
// FIXME: Undefined symbols are global, but this is the first place we
|
|
|
|
// are able to set it.
|
|
|
|
if (GetBinding(*it) == ELF::STB_LOCAL)
|
|
|
|
SetBinding(*it, ELF::STB_GLOBAL);
|
2010-08-17 02:57:57 +08:00
|
|
|
UndefinedSymbolData.push_back(MSD);
|
|
|
|
} else if (Symbol.isAbsolute()) {
|
|
|
|
MSD.SectionIndex = ELF::SHN_ABS;
|
|
|
|
ExternalSymbolData.push_back(MSD);
|
|
|
|
} else {
|
|
|
|
MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
|
|
|
|
assert(MSD.SectionIndex && "Invalid section index!");
|
|
|
|
ExternalSymbolData.push_back(MSD);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// Symbols are required to be in lexicographic order.
|
|
|
|
array_pod_sort(LocalSymbolData.begin(), LocalSymbolData.end());
|
|
|
|
array_pod_sort(ExternalSymbolData.begin(), ExternalSymbolData.end());
|
|
|
|
array_pod_sort(UndefinedSymbolData.begin(), UndefinedSymbolData.end());
|
|
|
|
|
|
|
|
// Set the symbol indices. Local symbols must come before all other
|
|
|
|
// symbols with non-local bindings.
|
|
|
|
Index = 0;
|
|
|
|
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
|
|
|
|
LocalSymbolData[i].SymbolData->setIndex(Index++);
|
|
|
|
for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
|
|
|
|
ExternalSymbolData[i].SymbolData->setIndex(Index++);
|
|
|
|
for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
|
|
|
|
UndefinedSymbolData[i].SymbolData->setIndex(Index++);
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriterImpl::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
|
|
|
|
const MCSectionData &SD) {
|
|
|
|
if (!Relocations[&SD].empty()) {
|
|
|
|
MCContext &Ctx = Asm.getContext();
|
|
|
|
const MCSection *RelaSection;
|
|
|
|
const MCSectionELF &Section =
|
|
|
|
static_cast<const MCSectionELF&>(SD.getSection());
|
|
|
|
|
|
|
|
const StringRef SectionName = Section.getSectionName();
|
2010-08-18 01:30:07 +08:00
|
|
|
std::string RelaSectionName = HasRelocationAddend ? ".rela" : ".rel";
|
2010-08-17 02:57:57 +08:00
|
|
|
RelaSectionName += SectionName;
|
2010-08-18 01:56:13 +08:00
|
|
|
|
|
|
|
unsigned EntrySize;
|
|
|
|
if (HasRelocationAddend)
|
|
|
|
EntrySize = Is64Bit ? sizeof(ELF::Elf64_Rela) : sizeof(ELF::Elf32_Rela);
|
|
|
|
else
|
|
|
|
EntrySize = Is64Bit ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
|
2010-08-17 02:57:57 +08:00
|
|
|
|
2010-08-18 01:30:07 +08:00
|
|
|
RelaSection = Ctx.getELFSection(RelaSectionName, HasRelocationAddend ?
|
|
|
|
ELF::SHT_RELA : ELF::SHT_REL, 0,
|
2010-08-17 02:57:57 +08:00
|
|
|
SectionKind::getReadOnly(),
|
|
|
|
false, EntrySize);
|
|
|
|
|
|
|
|
MCSectionData &RelaSD = Asm.getOrCreateSectionData(*RelaSection);
|
2010-09-07 00:11:52 +08:00
|
|
|
RelaSD.setAlignment(Is64Bit ? 8 : 4);
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
MCDataFragment *F = new MCDataFragment(&RelaSD);
|
|
|
|
|
|
|
|
WriteRelocationsFragment(Asm, F, &SD);
|
|
|
|
|
|
|
|
Asm.AddSectionToTheEnd(RelaSD, Layout);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriterImpl::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
|
|
|
|
uint64_t Flags, uint64_t Address,
|
|
|
|
uint64_t Offset, uint64_t Size,
|
|
|
|
uint32_t Link, uint32_t Info,
|
|
|
|
uint64_t Alignment,
|
|
|
|
uint64_t EntrySize) {
|
|
|
|
Write32(Name); // sh_name: index into string table
|
|
|
|
Write32(Type); // sh_type
|
|
|
|
WriteWord(Flags); // sh_flags
|
|
|
|
WriteWord(Address); // sh_addr
|
|
|
|
WriteWord(Offset); // sh_offset
|
|
|
|
WriteWord(Size); // sh_size
|
|
|
|
Write32(Link); // sh_link
|
|
|
|
Write32(Info); // sh_info
|
|
|
|
WriteWord(Alignment); // sh_addralign
|
|
|
|
WriteWord(EntrySize); // sh_entsize
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriterImpl::WriteRelocationsFragment(const MCAssembler &Asm,
|
|
|
|
MCDataFragment *F,
|
|
|
|
const MCSectionData *SD) {
|
|
|
|
std::vector<ELFRelocationEntry> &Relocs = Relocations[SD];
|
|
|
|
// sort by the r_offset just like gnu as does
|
|
|
|
array_pod_sort(Relocs.begin(), Relocs.end());
|
|
|
|
|
|
|
|
for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
|
|
|
|
ELFRelocationEntry entry = Relocs[e - i - 1];
|
|
|
|
|
2010-09-10 02:01:29 +08:00
|
|
|
if (Is64Bit) {
|
|
|
|
char buf[8];
|
2010-08-17 02:57:57 +08:00
|
|
|
|
2010-09-10 02:01:29 +08:00
|
|
|
String64(buf, entry.r_offset);
|
|
|
|
F->getContents() += StringRef(buf, 8);
|
|
|
|
|
|
|
|
String64(buf, entry.r_info);
|
|
|
|
F->getContents() += StringRef(buf, 8);
|
|
|
|
|
|
|
|
if (HasRelocationAddend) {
|
|
|
|
String64(buf, entry.r_addend);
|
|
|
|
F->getContents() += StringRef(buf, 8);
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
char buf[4];
|
|
|
|
|
|
|
|
String32(buf, entry.r_offset);
|
|
|
|
F->getContents() += StringRef(buf, 4);
|
|
|
|
|
|
|
|
String32(buf, entry.r_info);
|
|
|
|
F->getContents() += StringRef(buf, 4);
|
|
|
|
|
|
|
|
if (HasRelocationAddend) {
|
|
|
|
String32(buf, entry.r_addend);
|
|
|
|
F->getContents() += StringRef(buf, 4);
|
|
|
|
}
|
|
|
|
}
|
2010-08-17 02:57:57 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriterImpl::CreateMetadataSections(MCAssembler &Asm,
|
|
|
|
MCAsmLayout &Layout) {
|
|
|
|
MCContext &Ctx = Asm.getContext();
|
|
|
|
MCDataFragment *F;
|
|
|
|
|
|
|
|
const MCSection *SymtabSection;
|
|
|
|
unsigned EntrySize = Is64Bit ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
|
|
|
|
|
2010-09-17 03:46:31 +08:00
|
|
|
unsigned NumRegularSections = Asm.size();
|
|
|
|
|
2010-09-23 03:04:41 +08:00
|
|
|
// We construct .shstrtab, .symtab and .strtab in this order to match gnu as.
|
2010-09-17 03:46:31 +08:00
|
|
|
const MCSection *ShstrtabSection;
|
|
|
|
ShstrtabSection = Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0,
|
|
|
|
SectionKind::getReadOnly(), false);
|
|
|
|
MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection);
|
|
|
|
ShstrtabSD.setAlignment(1);
|
|
|
|
ShstrtabIndex = Asm.size();
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
SymtabSection = Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
|
|
|
|
SectionKind::getReadOnly(),
|
|
|
|
false, EntrySize);
|
|
|
|
MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection);
|
|
|
|
SymtabSD.setAlignment(Is64Bit ? 8 : 4);
|
|
|
|
|
|
|
|
const MCSection *StrtabSection;
|
|
|
|
StrtabSection = Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0,
|
|
|
|
SectionKind::getReadOnly(), false);
|
|
|
|
MCSectionData &StrtabSD = Asm.getOrCreateSectionData(*StrtabSection);
|
|
|
|
StrtabSD.setAlignment(1);
|
|
|
|
StringTableIndex = Asm.size();
|
|
|
|
|
2010-09-28 06:04:54 +08:00
|
|
|
WriteRelocations(Asm, Layout);
|
2010-09-17 03:46:31 +08:00
|
|
|
|
|
|
|
// Symbol table
|
|
|
|
F = new MCDataFragment(&SymtabSD);
|
|
|
|
WriteSymbolTable(F, Asm, Layout, NumRegularSections);
|
|
|
|
Asm.AddSectionToTheEnd(SymtabSD, Layout);
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
F = new MCDataFragment(&StrtabSD);
|
|
|
|
F->getContents().append(StringTable.begin(), StringTable.end());
|
|
|
|
Asm.AddSectionToTheEnd(StrtabSD, Layout);
|
|
|
|
|
|
|
|
F = new MCDataFragment(&ShstrtabSD);
|
|
|
|
|
|
|
|
// Section header string table.
|
|
|
|
//
|
|
|
|
// The first entry of a string table holds a null character so skip
|
|
|
|
// section 0.
|
|
|
|
uint64_t Index = 1;
|
|
|
|
F->getContents() += '\x00';
|
|
|
|
|
|
|
|
for (MCAssembler::const_iterator it = Asm.begin(),
|
|
|
|
ie = Asm.end(); it != ie; ++it) {
|
|
|
|
const MCSectionELF &Section =
|
2010-08-17 08:00:46 +08:00
|
|
|
static_cast<const MCSectionELF&>(it->getSection());
|
2010-09-23 22:14:56 +08:00
|
|
|
// FIXME: We could merge suffixes like in .text and .rela.text.
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
// Remember the index into the string table so we can write it
|
|
|
|
// into the sh_name field of the section header table.
|
|
|
|
SectionStringTableIndex[&it->getSection()] = Index;
|
|
|
|
|
|
|
|
Index += Section.getSectionName().size() + 1;
|
|
|
|
F->getContents() += Section.getSectionName();
|
|
|
|
F->getContents() += '\x00';
|
|
|
|
}
|
|
|
|
|
|
|
|
Asm.AddSectionToTheEnd(ShstrtabSD, Layout);
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriterImpl::WriteObject(const MCAssembler &Asm,
|
|
|
|
const MCAsmLayout &Layout) {
|
|
|
|
CreateMetadataSections(const_cast<MCAssembler&>(Asm),
|
|
|
|
const_cast<MCAsmLayout&>(Layout));
|
|
|
|
|
|
|
|
// Add 1 for the null section.
|
|
|
|
unsigned NumSections = Asm.size() + 1;
|
2010-09-07 00:11:52 +08:00
|
|
|
uint64_t NaturalAlignment = Is64Bit ? 8 : 4;
|
|
|
|
uint64_t HeaderSize = Is64Bit ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr);
|
|
|
|
uint64_t FileOff = HeaderSize;
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
for (MCAssembler::const_iterator it = Asm.begin(),
|
|
|
|
ie = Asm.end(); it != ie; ++it) {
|
|
|
|
const MCSectionData &SD = *it;
|
|
|
|
|
2010-09-07 00:11:52 +08:00
|
|
|
FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
// Get the size of the section in the output file (including padding).
|
|
|
|
uint64_t Size = Layout.getSectionFileSize(&SD);
|
2010-09-07 00:11:52 +08:00
|
|
|
|
|
|
|
FileOff += Size;
|
2010-08-17 02:57:57 +08:00
|
|
|
}
|
|
|
|
|
2010-09-07 00:11:52 +08:00
|
|
|
FileOff = RoundUpToAlignment(FileOff, NaturalAlignment);
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
// Write out the ELF header ...
|
2010-09-07 00:11:52 +08:00
|
|
|
WriteHeader(FileOff - HeaderSize, NumSections);
|
|
|
|
|
|
|
|
FileOff = HeaderSize;
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
// ... then all of the sections ...
|
|
|
|
DenseMap<const MCSection*, uint64_t> SectionOffsetMap;
|
|
|
|
|
2010-08-19 21:44:49 +08:00
|
|
|
DenseMap<const MCSection*, uint8_t> SectionIndexMap;
|
|
|
|
|
|
|
|
unsigned Index = 1;
|
2010-08-17 02:57:57 +08:00
|
|
|
for (MCAssembler::const_iterator it = Asm.begin(),
|
|
|
|
ie = Asm.end(); it != ie; ++it) {
|
2010-09-07 00:11:52 +08:00
|
|
|
const MCSectionData &SD = *it;
|
|
|
|
|
|
|
|
uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment());
|
|
|
|
WriteZeros(Padding);
|
|
|
|
FileOff += Padding;
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
// Remember the offset into the file for this section.
|
|
|
|
SectionOffsetMap[&it->getSection()] = FileOff;
|
2010-08-19 21:44:49 +08:00
|
|
|
SectionIndexMap[&it->getSection()] = Index++;
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
FileOff += Layout.getSectionFileSize(&SD);
|
|
|
|
|
|
|
|
Asm.WriteSectionData(it, Layout, Writer);
|
|
|
|
}
|
|
|
|
|
2010-09-07 00:11:52 +08:00
|
|
|
uint64_t Padding = OffsetToAlignment(FileOff, NaturalAlignment);
|
|
|
|
WriteZeros(Padding);
|
|
|
|
FileOff += Padding;
|
|
|
|
|
2010-08-17 02:57:57 +08:00
|
|
|
// ... and then the section header table.
|
|
|
|
// Should we align the section header table?
|
|
|
|
//
|
|
|
|
// Null section first.
|
|
|
|
WriteSecHdrEntry(0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
|
|
|
|
|
|
|
|
for (MCAssembler::const_iterator it = Asm.begin(),
|
|
|
|
ie = Asm.end(); it != ie; ++it) {
|
|
|
|
const MCSectionData &SD = *it;
|
|
|
|
const MCSectionELF &Section =
|
|
|
|
static_cast<const MCSectionELF&>(SD.getSection());
|
|
|
|
|
|
|
|
uint64_t sh_link = 0;
|
|
|
|
uint64_t sh_info = 0;
|
|
|
|
|
|
|
|
switch(Section.getType()) {
|
|
|
|
case ELF::SHT_DYNAMIC:
|
|
|
|
sh_link = SectionStringTableIndex[&it->getSection()];
|
|
|
|
sh_info = 0;
|
|
|
|
break;
|
|
|
|
|
|
|
|
case ELF::SHT_REL:
|
2010-08-17 03:15:06 +08:00
|
|
|
case ELF::SHT_RELA: {
|
2010-08-17 02:57:57 +08:00
|
|
|
const MCSection *SymtabSection;
|
|
|
|
const MCSection *InfoSection;
|
|
|
|
|
|
|
|
SymtabSection = Asm.getContext().getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
|
|
|
|
SectionKind::getReadOnly(),
|
2010-08-17 03:15:06 +08:00
|
|
|
false);
|
2010-08-19 21:44:49 +08:00
|
|
|
sh_link = SectionIndexMap[SymtabSection];
|
2010-08-17 02:57:57 +08:00
|
|
|
|
2010-08-18 01:30:07 +08:00
|
|
|
// Remove ".rel" and ".rela" prefixes.
|
|
|
|
unsigned SecNameLen = (Section.getType() == ELF::SHT_REL) ? 4 : 5;
|
|
|
|
StringRef SectionName = Section.getSectionName().substr(SecNameLen);
|
|
|
|
|
2010-08-17 03:15:06 +08:00
|
|
|
InfoSection = Asm.getContext().getELFSection(SectionName,
|
2010-08-17 02:57:57 +08:00
|
|
|
ELF::SHT_PROGBITS, 0,
|
2010-08-17 03:15:06 +08:00
|
|
|
SectionKind::getReadOnly(),
|
|
|
|
false);
|
2010-08-19 21:44:49 +08:00
|
|
|
sh_info = SectionIndexMap[InfoSection];
|
2010-08-17 02:57:57 +08:00
|
|
|
break;
|
2010-08-17 03:15:06 +08:00
|
|
|
}
|
2010-08-17 02:57:57 +08:00
|
|
|
|
|
|
|
case ELF::SHT_SYMTAB:
|
|
|
|
case ELF::SHT_DYNSYM:
|
|
|
|
sh_link = StringTableIndex;
|
|
|
|
sh_info = LastLocalSymbolIndex;
|
|
|
|
break;
|
|
|
|
|
|
|
|
case ELF::SHT_PROGBITS:
|
|
|
|
case ELF::SHT_STRTAB:
|
|
|
|
case ELF::SHT_NOBITS:
|
2010-09-01 01:03:33 +08:00
|
|
|
case ELF::SHT_NULL:
|
2010-08-17 02:57:57 +08:00
|
|
|
// Nothing to do.
|
|
|
|
break;
|
|
|
|
|
|
|
|
case ELF::SHT_HASH:
|
|
|
|
case ELF::SHT_GROUP:
|
|
|
|
case ELF::SHT_SYMTAB_SHNDX:
|
|
|
|
default:
|
|
|
|
assert(0 && "FIXME: sh_type value not supported!");
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
WriteSecHdrEntry(SectionStringTableIndex[&it->getSection()],
|
|
|
|
Section.getType(), Section.getFlags(),
|
2010-09-17 03:46:31 +08:00
|
|
|
0,
|
2010-08-17 02:57:57 +08:00
|
|
|
SectionOffsetMap.lookup(&SD.getSection()),
|
|
|
|
Layout.getSectionSize(&SD), sh_link,
|
|
|
|
sh_info, SD.getAlignment(),
|
|
|
|
Section.getEntrySize());
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
ELFObjectWriter::ELFObjectWriter(raw_ostream &OS,
|
|
|
|
bool Is64Bit,
|
2010-09-10 01:57:50 +08:00
|
|
|
Triple::OSType OSType,
|
2010-08-17 02:57:57 +08:00
|
|
|
bool IsLittleEndian,
|
|
|
|
bool HasRelocationAddend)
|
|
|
|
: MCObjectWriter(OS, IsLittleEndian)
|
|
|
|
{
|
2010-09-10 01:57:50 +08:00
|
|
|
Impl = new ELFObjectWriterImpl(this, Is64Bit, HasRelocationAddend, OSType);
|
2010-08-17 02:57:57 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
ELFObjectWriter::~ELFObjectWriter() {
|
|
|
|
delete (ELFObjectWriterImpl*) Impl;
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm) {
|
|
|
|
((ELFObjectWriterImpl*) Impl)->ExecutePostLayoutBinding(Asm);
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
|
|
|
|
const MCAsmLayout &Layout,
|
|
|
|
const MCFragment *Fragment,
|
|
|
|
const MCFixup &Fixup, MCValue Target,
|
|
|
|
uint64_t &FixedValue) {
|
|
|
|
((ELFObjectWriterImpl*) Impl)->RecordRelocation(Asm, Layout, Fragment, Fixup,
|
|
|
|
Target, FixedValue);
|
|
|
|
}
|
|
|
|
|
|
|
|
void ELFObjectWriter::WriteObject(const MCAssembler &Asm,
|
|
|
|
const MCAsmLayout &Layout) {
|
|
|
|
((ELFObjectWriterImpl*) Impl)->WriteObject(Asm, Layout);
|
|
|
|
}
|