diff options
| -rw-r--r-- | include/llvm/CodeGen/ELFWriter.h | 160 | ||||
| -rw-r--r-- | lib/CodeGen/ELFWriter.cpp | 310 |
2 files changed, 264 insertions, 206 deletions
diff --git a/include/llvm/CodeGen/ELFWriter.h b/include/llvm/CodeGen/ELFWriter.h index b2b00efa62..9211047f4a 100644 --- a/include/llvm/CodeGen/ELFWriter.h +++ b/include/llvm/CodeGen/ELFWriter.h @@ -15,6 +15,7 @@ #define LLVM_CODEGEN_ELFWRITER_H #include "llvm/CodeGen/MachineFunctionPass.h" +#include <list> namespace llvm { class GlobalVariable; @@ -35,6 +36,8 @@ namespace llvm { ~ELFWriter(); + typedef std::vector<unsigned char> DataBuffer; + protected: ELFWriter(std::ostream &O, TargetMachine &TM); @@ -85,14 +88,14 @@ namespace llvm { bool doFinalization(Module &M); private: - // The buffer we are accumulating the file into. Note that this should be + // The buffer we accumulate the file header into. Note that this should be // changed into something much more efficient later (and the bytecode writer // as well!). - std::vector<unsigned char> OutputBuffer; + DataBuffer FileHeader; /// ELFSection - This struct contains information about each section that is - /// emitted to the OutputBuffer. This is eventually turned into the section - /// header table at the end of the file. + /// emitted to the file. This is eventually turned into the section header + /// table at the end of the file. struct ELFSection { std::string Name; // Name of the section. unsigned NameIdx; // Index in .shstrtab of name, once emitted. @@ -106,6 +109,14 @@ namespace llvm { unsigned Align; unsigned EntSize; + /// SectionIdx - The number of the section in the Section Table. + /// + unsigned short SectionIdx; + + /// SectionData - The actual data for this section which we are building + /// up for emission to the file. + DataBuffer SectionData; + enum { SHT_NULL = 0, SHT_PROGBITS = 1, SHT_SYMTAB = 2, SHT_STRTAB = 3, SHT_RELA = 4, SHT_HASH = 5, SHT_DYNAMIC = 6, SHT_NOTE = 7, SHT_NOBITS = 8, SHT_REL = 9, SHT_SHLIB = 10, SHT_DYNSYM = 11 }; @@ -123,8 +134,8 @@ namespace llvm { SHF_TLS = 1 << 10,// Section holds thread-local data }; - ELFSection(const char *name = "", unsigned offset = 0) - : Name(name), Type(0), Flags(0), Addr(0), Offset(offset), Size(0), + ELFSection(const std::string &name) + : Name(name), Type(0), Flags(0), Addr(0), Offset(0), Size(0), Link(0), Info(0), Align(0), EntSize(0) { } }; @@ -132,7 +143,24 @@ namespace llvm { /// SectionList - This is the list of sections that we have emitted to the /// file. Once the file has been completely built, the section header table /// is constructed from this info. - std::vector<ELFSection> SectionList; + std::list<ELFSection> SectionList; + unsigned NumSections; // Always = SectionList.size() + + /// SectionLookup - This is a mapping from section name to section number in + /// the SectionList. + std::map<std::string, ELFSection*> SectionLookup; + + /// getSection - Return the section with the specified name, creating a new + /// section if one does not already exist. + ELFSection &getSection(const std::string &Name) { + ELFSection *&SN = SectionLookup[Name]; + if (SN) return *SN; + + SectionList.push_back(Name); + SN = &SectionList.back(); + SN->SectionIdx = NumSections++; + return *SN; + } /// ELFSym - This struct contains information about each symbol that is /// added to logical symbol table for the module. This is eventually @@ -163,103 +191,109 @@ namespace llvm { }; /// SymbolTable - This is the list of symbols we have emitted to the file. - /// This actually gets rearranged before emission to OutputBuffer (to put - /// the local symbols first in the list). + /// This actually gets rearranged before emission to the file (to put the + /// local symbols first in the list). std::vector<ELFSym> SymbolTable; - // As we accumulate the ELF file into OutputBuffer, we occasionally need to - // keep track of locations to update later (e.g. the location of the section - // table in the ELF header. These members keep track of the offset in - // OffsetBuffer of these various pieces to update and other locations in the - // file. + // As we complete the ELF file, we need to update fields in the ELF header + // (e.g. the location of the section table). These members keep track of + // the offset in ELFHeader of these various pieces to update and other + // locations in the file. unsigned ELFHeader_e_shoff_Offset; // e_shoff in ELF header. unsigned ELFHeader_e_shstrndx_Offset; // e_shstrndx in ELF header. unsigned ELFHeader_e_shnum_Offset; // e_shnum in ELF header. + // align - Emit padding into the file until the current output position is // aligned to the specified power of two boundary. - void align(unsigned Boundary) { + static void align(DataBuffer &Output, unsigned Boundary) { assert(Boundary && (Boundary & (Boundary-1)) == 0 && "Must align to 2^k boundary"); - while (OutputBuffer.size() & (Boundary-1)) - outbyte(0xAB); + size_t Size = Output.size(); + if (Size & (Boundary-1)) { + // Add padding to get alignment to the correct place. + size_t Pad = Boundary-(Size & (Boundary-1)); + Output.resize(Size+Pad); + } } - void outbyte(unsigned char X) { OutputBuffer.push_back(X); } - void outhalf(unsigned short X) { + static void outbyte(DataBuffer &Output, unsigned char X) { + Output.push_back(X); + } + void outhalf(DataBuffer &Output, unsigned short X) { if (isLittleEndian) { - OutputBuffer.push_back(X&255); - OutputBuffer.push_back(X >> 8); + Output.push_back(X&255); + Output.push_back(X >> 8); } else { - OutputBuffer.push_back(X >> 8); - OutputBuffer.push_back(X&255); + Output.push_back(X >> 8); + Output.push_back(X&255); } } - void outword(unsigned X) { + void outword(DataBuffer &Output, unsigned X) { if (isLittleEndian) { - OutputBuffer.push_back((X >> 0) & 255); - OutputBuffer.push_back((X >> 8) & 255); - OutputBuffer.push_back((X >> 16) & 255); - OutputBuffer.push_back((X >> 24) & 255); + Output.push_back((X >> 0) & 255); + Output.push_back((X >> 8) & 255); + Output.push_back((X >> 16) & 255); + Output.push_back((X >> 24) & 255); } else { - OutputBuffer.push_back((X >> 24) & 255); - OutputBuffer.push_back((X >> 16) & 255); - OutputBuffer.push_back((X >> 8) & 255); - OutputBuffer.push_back((X >> 0) & 255); + Output.push_back((X >> 24) & 255); + Output.push_back((X >> 16) & 255); + Output.push_back((X >> 8) & 255); + Output.push_back((X >> 0) & 255); } } - void outxword(uint64_t X) { + void outxword(DataBuffer &Output, uint64_t X) { if (isLittleEndian) { - OutputBuffer.push_back((X >> 0) & 255); - OutputBuffer.push_back((X >> 8) & 255); - OutputBuffer.push_back((X >> 16) & 255); - OutputBuffer.push_back((X >> 24) & 255); - OutputBuffer.push_back((X >> 32) & 255); - OutputBuffer.push_back((X >> 40) & 255); - OutputBuffer.push_back((X >> 48) & 255); - OutputBuffer.push_back((X >> 56) & 255); + Output.push_back((X >> 0) & 255); + Output.push_back((X >> 8) & 255); + Output.push_back((X >> 16) & 255); + Output.push_back((X >> 24) & 255); + Output.push_back((X >> 32) & 255); + Output.push_back((X >> 40) & 255); + Output.push_back((X >> 48) & 255); + Output.push_back((X >> 56) & 255); } else { - OutputBuffer.push_back((X >> 56) & 255); - OutputBuffer.push_back((X >> 48) & 255); - OutputBuffer.push_back((X >> 40) & 255); - OutputBuffer.push_back((X >> 32) & 255); - OutputBuffer.push_back((X >> 24) & 255); - OutputBuffer.push_back((X >> 16) & 255); - OutputBuffer.push_back((X >> 8) & 255); - OutputBuffer.push_back((X >> 0) & 255); + Output.push_back((X >> 56) & 255); + Output.push_back((X >> 48) & 255); + Output.push_back((X >> 40) & 255); + Output.push_back((X >> 32) & 255); + Output.push_back((X >> 24) & 255); + Output.push_back((X >> 16) & 255); + Output.push_back((X >> 8) & 255); + Output.push_back((X >> 0) & 255); } } - void outaddr32(unsigned X) { - outword(X); + void outaddr32(DataBuffer &Output, unsigned X) { + outword(Output, X); } - void outaddr64(uint64_t X) { - outxword(X); + void outaddr64(DataBuffer &Output, uint64_t X) { + outxword(Output, X); } - void outaddr(uint64_t X) { + void outaddr(DataBuffer &Output, uint64_t X) { if (!is64Bit) - outword((unsigned)X); + outword(Output, (unsigned)X); else - outxword(X); + outxword(Output, X); } // fix functions - Replace an existing entry at an offset. - void fixhalf(unsigned short X, unsigned Offset) { - unsigned char *P = &OutputBuffer[Offset]; + void fixhalf(DataBuffer &Output, unsigned short X, unsigned Offset) { + unsigned char *P = &Output[Offset]; P[0] = (X >> (isLittleEndian ? 0 : 8)) & 255; P[1] = (X >> (isLittleEndian ? 8 : 0)) & 255; } - void fixword(unsigned X, unsigned Offset) { - unsigned char *P = &OutputBuffer[Offset]; + void fixword(DataBuffer &Output, unsigned X, unsigned Offset) { + unsigned char *P = &Output[Offset]; P[0] = (X >> (isLittleEndian ? 0 : 24)) & 255; P[1] = (X >> (isLittleEndian ? 8 : 16)) & 255; P[2] = (X >> (isLittleEndian ? 16 : 8)) & 255; P[3] = (X >> (isLittleEndian ? 24 : 0)) & 255; } - void fixaddr(uint64_t X, unsigned Offset) { + void fixaddr(DataBuffer &Output, uint64_t X, unsigned Offset) { if (!is64Bit) - fixword((unsigned)X, Offset); + fixword(Output, (unsigned)X, Offset); else assert(0 && "Emission of 64-bit data not implemented yet!"); } @@ -271,7 +305,7 @@ namespace llvm { void EmitSymbolTable(); void EmitSectionTableStringTable(); - void EmitSectionTable(); + void OutputSectionsAndSectionTable(); }; } diff --git a/lib/CodeGen/ELFWriter.cpp b/lib/CodeGen/ELFWriter.cpp index cc8895df09..c9d1ae4041 100644 --- a/lib/CodeGen/ELFWriter.cpp +++ b/lib/CodeGen/ELFWriter.cpp @@ -49,10 +49,11 @@ namespace llvm { /// functions to the ELF file. class ELFCodeEmitter : public MachineCodeEmitter { ELFWriter &EW; - std::vector<unsigned char> &OutputBuffer; + ELFWriter::ELFSection *ES; // Section to write to. + std::vector<unsigned char> *OutBuffer; size_t FnStart; public: - ELFCodeEmitter(ELFWriter &ew) : EW(ew), OutputBuffer(EW.OutputBuffer) {} + ELFCodeEmitter(ELFWriter &ew) : EW(ew), OutBuffer(0) {} void startFunction(MachineFunction &F); void finishFunction(MachineFunction &F); @@ -62,7 +63,7 @@ namespace llvm { assert(0 && "unimp"); } virtual void emitByte(unsigned char B) { - OutputBuffer.push_back(B); + OutBuffer->push_back(B); } virtual void emitWordAt(unsigned W, unsigned *Ptr) { assert(0 && "ni"); @@ -71,10 +72,10 @@ namespace llvm { assert(0 && "ni"); } virtual uint64_t getCurrentPCValue() { - return OutputBuffer.size(); + return OutBuffer->size(); } virtual uint64_t getCurrentPCOffset() { - return OutputBuffer.size()-FnStart; + return OutBuffer->size()-FnStart; } void addRelocation(const MachineRelocation &MR) { assert(0 && "relo not handled yet!"); @@ -102,21 +103,22 @@ namespace llvm { void ELFCodeEmitter::startFunction(MachineFunction &F) { // Align the output buffer to the appropriate alignment. unsigned Align = 16; // FIXME: GENERICIZE!! - ELFWriter::ELFSection &TextSection = EW.SectionList.back(); + // Get the ELF Section that this function belongs in. + ES = &EW.getSection(".text"); + ES->Type = ELFWriter::ELFSection::SHT_PROGBITS; + ES->Flags = ELFWriter::ELFSection::SHF_EXECINSTR | + ELFWriter::ELFSection::SHF_ALLOC; + OutBuffer = &ES->SectionData; // Upgrade the section alignment if required. - if (TextSection.Align < Align) TextSection.Align = Align; + if (ES->Align < Align) ES->Align = Align; // Add padding zeros to the end of the buffer to make sure that the // function will start on the correct byte alignment within the section. - size_t SectionOff = OutputBuffer.size()-TextSection.Offset; - if (SectionOff & (Align-1)) { - // Add padding to get alignment to the correct place. - size_t Pad = Align-(SectionOff & (Align-1)); - OutputBuffer.resize(OutputBuffer.size()+Pad); - } + size_t SectionOff = OutBuffer->size(); + ELFWriter::align(*OutBuffer, Align); - FnStart = OutputBuffer.size(); + FnStart = OutBuffer->size(); } /// finishFunction - This callback is invoked after the function is completely @@ -141,12 +143,13 @@ void ELFCodeEmitter::finishFunction(MachineFunction &F) { FnSym.SetBind(ELFWriter::ELFSym::STB_LOCAL); break; } - + + ES->Size = OutBuffer->size(); + FnSym.SetType(ELFWriter::ELFSym::STT_FUNC); - FnSym.SectionIdx = EW.SectionList.size()-1; // .text section. - // Value = Offset from start of .text - FnSym.Value = FnStart - EW.SectionList.back().Offset; - FnSym.Size = OutputBuffer.size()-FnStart; + FnSym.SectionIdx = ES->SectionIdx; + FnSym.Value = FnStart; // Value = Offset from start of Section. + FnSym.Size = OutBuffer->size()-FnStart; // Finally, add it to the symtab. EW.SymbolTable.push_back(FnSym); @@ -165,6 +168,7 @@ ELFWriter::ELFWriter(std::ostream &o, TargetMachine &tm) : O(o), TM(tm) { // Create the machine code emitter object for this target. MCE = new ELFCodeEmitter(*this); + NumSections = 0; } ELFWriter::~ELFWriter() { @@ -176,47 +180,47 @@ ELFWriter::~ELFWriter() { bool ELFWriter::doInitialization(Module &M) { Mang = new Mangler(M); - outbyte(0x7F); // EI_MAG0 - outbyte('E'); // EI_MAG1 - outbyte('L'); // EI_MAG2 - outbyte('F'); // EI_MAG3 - outbyte(is64Bit ? 2 : 1); // EI_CLASS - outbyte(isLittleEndian ? 1 : 2); // EI_DATA - outbyte(1); // EI_VERSION - for (unsigned i = OutputBuffer.size(); i != 16; ++i) - outbyte(0); // EI_PAD up to 16 bytes. + // Local alias to shortenify coming code. + std::vector<unsigned char> &FH = FileHeader; + + outbyte(FH, 0x7F); // EI_MAG0 + outbyte(FH, 'E'); // EI_MAG1 + outbyte(FH, 'L'); // EI_MAG2 + outbyte(FH, 'F'); // EI_MAG3 + outbyte(FH, is64Bit ? 2 : 1); // EI_CLASS + outbyte(FH, isLittleEndian ? 1 : 2); // EI_DATA + outbyte(FH, 1); // EI_VERSION + FH.resize(16); // EI_PAD up to 16 bytes. // This should change for shared objects. - outhalf(1); // e_type = ET_REL - outhalf(e_machine); // e_machine = whatever the target wants - outword(1); // e_version = 1 - outaddr(0); // e_entry = 0 -> no entry point in .o file - outaddr(0); // e_phoff = 0 -> no program header for .o + outhalf(FH, 1); // e_type = ET_REL + outhalf(FH, e_machine); // e_machine = whatever the target wants + outword(FH, 1); // e_version = 1 + outaddr(FH, 0); // e_entry = 0 -> no entry point in .o file + outaddr(FH, 0); // e_phoff = 0 -> no program header for .o - ELFHeader_e_shoff_Offset = OutputBuffer.size(); - outaddr(0); // e_shoff - outword(e_flags); // e_flags = whatever the target wants + ELFHeader_e_shoff_Offset = FH.size(); + outaddr(FH, 0); // e_shoff + outword(FH, e_flags); // e_flags = whatever the target wants - outhalf(is64Bit ? 64 : 52); // e_ehsize = ELF header size - outhalf(0); // e_phentsize = prog header entry size - outhalf(0); // e_phnum = # prog header entries = 0 - outhalf(is64Bit ? 64 : 40); // e_shentsize = sect header entry size + outhalf(FH, is64Bit ? 64 : 52); // e_ehsize = ELF header size + outhalf(FH, 0); // e_phentsize = prog header entry size + outhalf(FH, 0); // e_phnum = # prog header entries = 0 + outhalf(FH, is64Bit ? 64 : 40); // e_shentsize = sect hdr entry size - ELFHeader_e_shnum_Offset = OutputBuffer.size(); - outhalf(0); // e_shnum = # of section header ents - ELFHeader_e_shstrndx_Offset = OutputBuffer.size(); - outhalf(0); // e_shstrndx = Section # of '.shstrtab' + ELFHeader_e_shnum_Offset = FH.size(); + outhalf(FH, 0); // e_shnum = # of section header ents + ELFHeader_e_shstrndx_Offset = FH.size(); + outhalf(FH, 0); // e_shstrndx = Section # of '.shstrtab' - // Add the null section. - SectionList.push_back(ELFSection()); + // Add the null section, which is required to be first in the file. + getSection(""); // Start up the symbol table. The first entry in the symtab is the null // entry. SymbolTable.push_back(ELFSym(0)); - SectionList.push_back(ELFSection(".text", OutputBuffer.size())); - return false; } @@ -286,7 +290,7 @@ void ELFWriter::EmitGlobal(GlobalVariable *GV, ELFSection &DataSection, } // Set the idx of the .bss section - BSSSym.SectionIdx = &BSSSection-&SectionList[0]; + BSSSym.SectionIdx = BSSSection.SectionIdx; SymbolTable.push_back(BSSSym); // Reserve space in the .bss section for this symbol. @@ -310,40 +314,19 @@ bool ELFWriter::runOnMachineFunction(MachineFunction &MF) { /// doFinalization - Now that the module has been completely processed, emit /// the ELF file to 'O'. bool ELFWriter::doFinalization(Module &M) { - // Okay, the .text section has now been finalized. If it contains nothing, do - // not emit it. - uint64_t TextSize = OutputBuffer.size() - SectionList.back().Offset; - if (TextSize == 0) { - SectionList.pop_back(); - } else { - ELFSection &Text = SectionList.back(); - Text.Size = TextSize; - Text.Type = ELFSection::SHT_PROGBITS; - Text.Flags = ELFSection::SHF_EXECINSTR | ELFSection::SHF_ALLOC; - } - // Okay, the ELF header and .text sections have been completed, build the // .data, .bss, and "common" sections next. - SectionList.push_back(ELFSection(".data", OutputBuffer.size())); - SectionList.push_back(ELFSection(".bss")); - ELFSection &DataSection = *(SectionList.end()-2); - ELFSection &BSSSection = SectionList.back(); - for (Module::global_iterator I = M.global_begin(), E = M.global_end(); - I != E; ++I) - EmitGlobal(I, DataSection, BSSSection); - - // Finish up the data section. + ELFSection &DataSection = getSection(".data"); DataSection.Type = ELFSection::SHT_PROGBITS; DataSection.Flags = ELFSection::SHF_WRITE | ELFSection::SHF_ALLOC; - // The BSS Section logically starts at the end of the Data Section (adjusted - // to the required alignment of the BSSSection). - BSSSection.Offset = DataSection.Offset+DataSection.Size; + ELFSection &BSSSection = getSection(".bss"); BSSSection.Type = ELFSection::SHT_NOBITS; BSSSection.Flags = ELFSection::SHF_WRITE | ELFSection::SHF_ALLOC; - if (BSSSection.Align) - BSSSection.Offset = (BSSSection.Offset+BSSSection.Align-1) & - ~(BSSSection.Align-1); + + for (Module::global_iterator I = M.global_begin(), E = M.global_end(); + I != E; ++I) + EmitGlobal(I, DataSection, BSSSection); // Emit the symbol table now, if non-empty. EmitSymbolTable(); @@ -353,14 +336,12 @@ bool ELFWriter::doFinalization(Module &M) { // Emit the string table for the sections in the ELF file we have. EmitSectionTableStringTable(); - // Emit the .o file section table. - EmitSectionTable(); + // Emit the sections to the .o file, and emit the section table for the file. + OutputSectionsAndSectionTable(); - // Emit the .o file to the specified stream. - O.write((char*)&OutputBuffer[0], OutputBuffer.size()); - - // Free the output buffer. - std::vector<unsigned char>().swap(OutputBuffer); + // We are done with the abstract symbols. + SectionList.clear(); + NumSections = 0; // Release the name mangler object. delete Mang; Mang = 0; @@ -375,13 +356,14 @@ void ELFWriter::EmitSymbolTable() { // FIXME: compact all local symbols to the start of the symtab. unsigned FirstNonLocalSymbol = 1; - SectionList.push_back(ELFSection(".strtab", OutputBuffer.size())); - ELFSection &StrTab = SectionList.back(); + ELFSection &StrTab = getSection(".strtab"); StrTab.Type = ELFSection::SHT_STRTAB; StrTab.Align = 1; + DataBuffer &StrTabBuf = StrTab.SectionData; + // Set the zero'th symbol to a null byte, as required. - outbyte(0); + outbyte(StrTabBuf, 0); SymbolTable[0].NameIdx = 0; unsigned Index = 1; for (unsigned i = 1, e = SymbolTable.size(); i != e; ++i) { @@ -394,53 +376,51 @@ void ELFWriter::EmitSymbolTable() { SymbolTable[i].NameIdx = Index; // Add the name to the output buffer, including the null terminator. - OutputBuffer.insert(OutputBuffer.end(), Name.begin(), Name.end()); + StrTabBuf.insert(StrTabBuf.end(), Name.begin(), Name.end()); // Add a null terminator. - OutputBuffer.push_back(0); + StrTabBuf.push_back(0); // Keep track of the number of bytes emitted to this section. Index += Name.size()+1; } } - - StrTab.Size = OutputBuffer.size()-StrTab.Offset; + assert(Index == StrTabBuf.size()); + StrTab.Size = Index; // Now that we have emitted the string table and know the offset into the // string table of each symbol, emit the symbol table itself. - align(is64Bit ? 8 : 4); - - SectionList.push_back(ELFSection(".symtab", OutputBuffer.size())); - ELFSection &SymTab = SectionList.back(); + ELFSection &SymTab = getSection(".symtab"); SymTab.Type = ELFSection::SHT_SYMTAB; SymTab.Align = is64Bit ? 8 : 4; - SymTab.Link = SectionList.size()-2; // Section Index of .strtab. + SymTab.Link = SymTab.SectionIdx; // Section Index of .strtab. SymTab.Info = FirstNonLocalSymbol; // First non-STB_LOCAL symbol. SymTab.EntSize = 16; // Size of each symtab entry. FIXME: wrong for ELF64 + DataBuffer &SymTabBuf = SymTab.SectionData; if (!is64Bit) { // 32-bit and 64-bit formats are shuffled a bit. for (unsigned i = 0, e = SymbolTable.size(); i != e; ++i) { ELFSym &Sym = SymbolTable[i]; - outword(Sym.NameIdx); - outaddr32(Sym.Value); - outword(Sym.Size); - outbyte(Sym.Info); - outbyte(Sym.Other); - outhalf(Sym.SectionIdx); + outword(SymTabBuf, Sym.NameIdx); + outaddr32(SymTabBuf, Sym.Value); + outword(SymTabBuf, Sym.Size); + outbyte(SymTabBuf, Sym.Info); + outbyte(SymTabBuf, Sym.Other); + outhalf(SymTabBuf, Sym.SectionIdx); } } else { for (unsigned i = 0, e = SymbolTable.size(); i != e; ++i) { ELFSym &Sym = SymbolTable[i]; - outword(Sym.NameIdx); - outbyte(Sym.Info); - outbyte(Sym.Other); - outhalf(Sym.SectionIdx); - outaddr64(Sym.Value); - outxword(Sym.Size); + outword(SymTabBuf, Sym.NameIdx); + outbyte(SymTabBuf, Sym.Info); + outbyte(SymTabBuf, Sym.Other); + outhalf(SymTabBuf, Sym.SectionIdx); + outaddr64(SymTabBuf, Sym.Value); + outxword(SymTabBuf, Sym.Size); } } - SymTab.Size = OutputBuffer.size()-SymTab.Offset; + SymTab.Size = SymTabBuf.size(); } /// EmitSectionTableStringTable - This method adds and emits a section for the @@ -448,63 +428,107 @@ void ELFWriter::EmitSymbolTable() { /// section names. void ELFWriter::EmitSectionTableStringTable() { // First step: add the section for the string table to the list of sections: - SectionList.push_back(ELFSection(".shstrtab", OutputBuffer.size())); - SectionList.back().Type = ELFSection::SHT_STRTAB; + ELFSection &SHStrTab = getSection(".shstrtab"); + SHStrTab.Type = ELFSection::SHT_STRTAB; // Now that we know which section number is the .shstrtab section, update the // e_shstrndx entry in the ELF header. - fixhalf(SectionList.size()-1, ELFHeader_e_shstrndx_Offset); + fixhalf(FileHeader, SHStrTab.SectionIdx, ELFHeader_e_shstrndx_Offset); // Set the NameIdx of each section in the string table and emit the bytes for // the string table. unsigned Index = 0; + DataBuffer &Buf = SHStrTab.SectionData; - for (unsigned i = 0, e = SectionList.size(); i != e; ++i) { + for (std::list<ELFSection>::iterator I = SectionList.begin(), + E = SectionList.end(); I != E; ++I) { // Set the index into the table. Note if we have lots of entries with // common suffixes, we could memoize them here if we cared. - SectionList[i].NameIdx = Index; + I->NameIdx = Index; // Add the name to the output buffer, including the null terminator. - OutputBuffer.insert(OutputBuffer.end(), SectionList[i].Name.begin(), - SectionList[i].Name.end()); + Buf.insert(Buf.end(), I->Name.begin(), I->Name.end()); + // Add a null terminator. - OutputBuffer.push_back(0); + Buf.push_back(0); // Keep track of the number of bytes emitted to this section. - Index += SectionList[i].Name.size()+1; + Index += I->Name.size()+1; } // Set the size of .shstrtab now that we know what it is. - SectionList.back().Size = Index; + assert(Index == Buf.size()); + SHStrTab.Size = Index; } -/// EmitSectionTable - Now that we have emitted the entire contents of the file -/// (all of the sections), emit the section table which informs the reader where -/// the boundaries are. -void ELFWriter::EmitSectionTable() { - // Now that all of the sections have been emitted, set the e_shnum entry in - // the ELF header. - fixhalf(SectionList.size(), ELFHeader_e_shnum_Offset); +/// OutputSectionsAndSectionTable - Now that we have constructed the file header +/// and all of the sections, emit these to the ostream destination and emit the +/// SectionTable. +void ELFWriter::OutputSectionsAndSectionTable() { + // Pass #1: Compute the file offset for each section. + size_t FileOff = FileHeader.size(); // File header first. + + // Emit all of the section data in order. + for (std::list<ELFSection>::iterator I = SectionList.begin(), + E = SectionList.end(); I != E; ++I) { + // Align FileOff to whatever the alignment restrictions of the section are. + if (I->Align) + FileOff = (FileOff+I->Align-1) & ~(I->Align-1); + I->Offset = FileOff; + FileOff += I->SectionData.size(); + } + + // Align Section Header. + unsigned TableAlign = is64Bit ? 8 : 4; + FileOff = (FileOff+TableAlign-1) & ~(TableAlign-1); + + // Now that we know where all of the sections will be emitted, set the e_shnum + // entry in the ELF header. + fixhalf(FileHeader, NumSections, ELFHeader_e_shnum_Offset); - // Now that we know the offset in the file of the section table (which we emit - // next), update the e_shoff address in the ELF header. - fixaddr(OutputBuffer.size(), ELFHeader_e_shoff_Offset); + // Now that we know the offset in the file of the section table, update the + // e_shoff address in the ELF header. + fixaddr(FileHeader, FileOff, ELFHeader_e_shoff_Offset); - // Emit all of the section table entries. - for (unsigned i = 0, e = SectionList.size(); i != e; ++i) { - const ELFSection &S = SectionList[i]; - outword(S.NameIdx); // sh_name - Symbol table name idx - outword(S.Type); // sh_type - Section contents & semantics - outword(S.Flags); // sh_flags - Section flags. - outaddr(S.Addr); // sh_addr - The mem address this section appears in. - outaddr(S.Offset); // sh_offset - The offset from the start of the file. - outword(S.Size); // sh_size - The section size. - outword(S.Link); // sh_link - Section header table index link. - outword(S.Info); // sh_info - Auxillary information. - outword(S.Align); // sh_addralign - Alignment of section. - outword(S.EntSize); // sh_entsize - Size of each entry in the section. + // Now that we know all of the data in the file header, emit it and all of the + // sections! + O.write((char*)&FileHeader[0], FileHeader.size()); + FileOff = FileHeader.size(); + DataBuffer().swap(FileHeader); + + DataBuffer Table; + + // Emit all of the section data and build the section table itself. + while (!SectionList.empty()) { + const ELFSection &S = *SectionList.begin(); + + // Align FileOff to whatever the alignment restrictions of the section are. + if (S.Align) + for (size_t NewFileOff = (FileOff+S.Align-1) & ~(S.Align-1); + FileOff != NewFileOff; ++FileOff) + O.put(0xAB); + O.write((char*)&S.SectionData[0], S.SectionData.size()); + FileOff += S.SectionData.size(); + + outword(Table, S.NameIdx); // sh_name - Symbol table name idx + outword(Table, S.Type); // sh_type - Section contents & semantics + outword(Table, S.Flags); // sh_flags - Section flags. + outaddr(Table, S.Addr); // sh_addr - The mem addr this section is in. + outaddr(Table, S.Offset); // sh_offset - Offset from the file start. + outword(Table, S.Size); // sh_size - The section size. + outword(Table, S.Link); // sh_link - Section header table index link. + outword(Table, S.Info); // sh_info - Auxillary information. + outword(Table, S.Align); // sh_addralign - Alignment of section. + outword(Table, S.EntSize); // sh_entsize - Size of entries in the section. + + SectionList.pop_front(); } - // Release the memory allocated for the section list. - std::vector<ELFSection>().swap(SectionList); + // Align output for the section table. + for (size_t NewFileOff = (FileOff+TableAlign-1) & ~(TableAlign-1); + FileOff != NewFileOff; ++FileOff) + O.put(0xAB); + + // Emit the section table itself. + O.write((char*)&Table[0], Table.size()); } |