X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FELFWriter.cpp;h=27f23f45cc0677af6a4466367e17eee8cb30e127;hb=990f032907ae171cc3d465a694e8e6d2a6545f57;hp=265adaba00aea4c6337a54edd7979bfaeb086afd;hpb=0e180507975c31d584e0a3ca992ead7709e74f13;p=oota-llvm.git diff --git a/lib/CodeGen/ELFWriter.cpp b/lib/CodeGen/ELFWriter.cpp index 265adaba00a..27f23f45cc0 100644 --- a/lib/CodeGen/ELFWriter.cpp +++ b/lib/CodeGen/ELFWriter.cpp @@ -2,8 +2,8 @@ // // The LLVM Compiler Infrastructure // -// This file was developed by the LLVM research group and is distributed under -// the University of Illinois Open Source License. See LICENSE.TXT for details. +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // @@ -25,21 +25,39 @@ // #3. ".bss" entry - global variables without initializers. [ if needed ] // ... // #N. ".shstrtab" entry - String table for the section names. - // // NOTE: This code should eventually be extended to support 64-bit ELF (this // won't be hard), but we haven't done so yet! // //===----------------------------------------------------------------------===// -#include "llvm/CodeGen/ELFWriter.h" +#include "ELFWriter.h" #include "llvm/Module.h" +#include "llvm/PassManager.h" +#include "llvm/CodeGen/FileWriters.h" #include "llvm/CodeGen/MachineCodeEmitter.h" #include "llvm/CodeGen/MachineConstantPool.h" +#include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/Target/TargetData.h" +#include "llvm/Target/TargetELFWriterInfo.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Support/Mangler.h" +#include "llvm/Support/OutputBuffer.h" +#include "llvm/Support/Streams.h" +#include using namespace llvm; +char ELFWriter::ID = 0; +/// AddELFWriter - Concrete function to add the ELF writer to the function pass +/// manager. +MachineCodeEmitter *llvm::AddELFWriter(PassManagerBase &PM, + std::ostream &O, + TargetMachine &TM) { + ELFWriter *EW = new ELFWriter(O, TM); + PM.add(EW); + return &EW->getMachineCodeEmitter(); +} + //===----------------------------------------------------------------------===// // ELFCodeEmitter Implementation //===----------------------------------------------------------------------===// @@ -49,46 +67,59 @@ namespace llvm { /// functions to the ELF file. class ELFCodeEmitter : public MachineCodeEmitter { ELFWriter &EW; - std::vector &OutputBuffer; + TargetMachine &TM; + ELFWriter::ELFSection *ES; // Section to write to. + std::vector *OutBuffer; size_t FnStart; public: - ELFCodeEmitter(ELFWriter &ew) : EW(ew), OutputBuffer(EW.OutputBuffer) {} + explicit ELFCodeEmitter(ELFWriter &ew) : EW(ew), TM(EW.TM), OutBuffer(0) {} void startFunction(MachineFunction &F); - void finishFunction(MachineFunction &F); + bool finishFunction(MachineFunction &F); - void emitConstantPool(MachineConstantPool *MCP) { - if (MCP->isEmpty()) return; - assert(0 && "unimp"); - } - virtual void emitByte(unsigned char B) { - OutputBuffer.push_back(B); + void addRelocation(const MachineRelocation &MR) { + assert(0 && "relo not handled yet!"); } - virtual void emitWordAt(unsigned W, unsigned *Ptr) { - assert(0 && "ni"); + + virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) { } - virtual void emitWord(unsigned W) { - assert(0 && "ni"); + + virtual intptr_t getConstantPoolEntryAddress(unsigned Index) const { + assert(0 && "CP not implementated yet!"); + return 0; } - virtual uint64_t getCurrentPCValue() { - return OutputBuffer.size(); + virtual intptr_t getJumpTableEntryAddress(unsigned Index) const { + assert(0 && "JT not implementated yet!"); + return 0; } - virtual uint64_t getCurrentPCOffset() { - return OutputBuffer.size()-FnStart; + + virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const { + assert(0 && "JT not implementated yet!"); + return 0; } - void addRelocation(const MachineRelocation &MR) { - assert(0 && "relo not handled yet!"); + + virtual intptr_t getLabelAddress(uint64_t Label) const { + assert(0 && "Label address not implementated yet!"); + abort(); + return 0; } - virtual uint64_t getConstantPoolEntryAddress(unsigned Index) { - assert(0 && "CP not implementated yet!"); + + virtual void emitLabel(uint64_t LabelID) { + assert(0 && "emit Label not implementated yet!"); + abort(); } + + virtual void setModuleInfo(llvm::MachineModuleInfo* MMI) { } + + /// JIT SPECIFIC FUNCTIONS - DO NOT IMPLEMENT THESE HERE! - void startFunctionStub(unsigned StubSize) { + void startFunctionStub(const GlobalValue* F, unsigned StubSize, + unsigned Alignment = 1) { assert(0 && "JIT specific function called!"); abort(); } - void *finishFunctionStub(const Function *F) { + void *finishFunctionStub(const GlobalValue *F) { assert(0 && "JIT specific function called!"); abort(); return 0; @@ -101,29 +132,34 @@ 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", ELFWriter::ELFSection::SHT_PROGBITS, + ELFWriter::ELFSection::SHF_EXECINSTR | + ELFWriter::ELFSection::SHF_ALLOC); + OutBuffer = &ES->SectionData; + cerr << "FIXME: This code needs to be updated for changes in the " + << "CodeEmitter interfaces. In particular, this should set " + << "BufferBegin/BufferEnd/CurBufferPtr, not deal with OutBuffer!"; + abort(); + // 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); - } - - FnStart = OutputBuffer.size(); + OutputBuffer OB(*OutBuffer, + TM.getTargetData()->getPointerSizeInBits() == 64, + TM.getTargetData()->isLittleEndian()); + OB.align(Align); + FnStart = OutBuffer->size(); } /// finishFunction - This callback is invoked after the function is completely /// finished. -void ELFCodeEmitter::finishFunction(MachineFunction &F) { +bool ELFCodeEmitter::finishFunction(MachineFunction &F) { // We now know the size of the function, add a symbol to represent it. ELFWriter::ELFSym FnSym(F.getFunction()); - + // Figure out the binding (linkage) of the symbol. switch (F.getFunction()->getLinkage()) { default: @@ -140,30 +176,33 @@ 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); + return false; } //===----------------------------------------------------------------------===// // ELFWriter Implementation //===----------------------------------------------------------------------===// -ELFWriter::ELFWriter(std::ostream &o, TargetMachine &tm) : O(o), TM(tm) { - e_machine = 0; // e_machine defaults to 'No Machine' +ELFWriter::ELFWriter(std::ostream &o, TargetMachine &tm) + : MachineFunctionPass((intptr_t)&ID), O(o), TM(tm) { e_flags = 0; // e_flags defaults to 0, no flags. - is64Bit = TM.getTargetData().getPointerSizeInBits() == 64; - isLittleEndian = TM.getTargetData().isLittleEndian(); + is64Bit = TM.getTargetData()->getPointerSizeInBits() == 64; + isLittleEndian = TM.getTargetData()->isLittleEndian(); // Create the machine code emitter object for this target. MCE = new ELFCodeEmitter(*this); + NumSections = 0; } ELFWriter::~ELFWriter() { @@ -175,53 +214,52 @@ 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 &FH = FileHeader; + OutputBuffer FHOut(FH, is64Bit, isLittleEndian); + + FHOut.outbyte(0x7F); // EI_MAG0 + FHOut.outbyte('E'); // EI_MAG1 + FHOut.outbyte('L'); // EI_MAG2 + FHOut.outbyte('F'); // EI_MAG3 + FHOut.outbyte(is64Bit ? 2 : 1); // EI_CLASS + FHOut.outbyte(isLittleEndian ? 1 : 2); // EI_DATA + FHOut.outbyte(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 - - ELFHeader_e_shoff_Offset = OutputBuffer.size(); - outaddr(0); // e_shoff - outword(e_flags); // e_flags = whatever the target wants - - assert(!is64Bit && "These sizes need to be adjusted for 64-bit!"); - outhalf(52); // e_ehsize = ELF header size - outhalf(0); // e_phentsize = prog header entry size - outhalf(0); // e_phnum = # prog header entries = 0 - outhalf(40); // e_shentsize = sect header 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' - - // Add the null section. - SectionList.push_back(ELFSection()); + FHOut.outhalf(1); // e_type = ET_REL + FHOut.outhalf(TM.getELFWriterInfo()->getEMachine()); // target-defined + FHOut.outword(1); // e_version = 1 + FHOut.outaddr(0); // e_entry = 0 -> no entry point in .o file + FHOut.outaddr(0); // e_phoff = 0 -> no program header for .o + + ELFHeader_e_shoff_Offset = FH.size(); + FHOut.outaddr(0); // e_shoff + FHOut.outword(e_flags); // e_flags = whatever the target wants + + FHOut.outhalf(is64Bit ? 64 : 52); // e_ehsize = ELF header size + FHOut.outhalf(0); // e_phentsize = prog header entry size + FHOut.outhalf(0); // e_phnum = # prog header entries = 0 + FHOut.outhalf(is64Bit ? 64 : 40); // e_shentsize = sect hdr entry size + + + ELFHeader_e_shnum_Offset = FH.size(); + FHOut.outhalf(0); // e_shnum = # of section header ents + ELFHeader_e_shstrndx_Offset = FH.size(); + FHOut.outhalf(0); // e_shstrndx = Section # of '.shstrtab' + + // Add the null section, which is required to be first in the file. + getSection("", 0, 0); // 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; } -void ELFWriter::EmitGlobal(GlobalVariable *GV, ELFSection &DataSection, - ELFSection &BSSSection) { +void ELFWriter::EmitGlobal(GlobalVariable *GV) { // If this is an external global, emit it now. TODO: Note that it would be // better to ignore the symbol here and only add it to the symbol table if // referenced. @@ -233,10 +271,10 @@ void ELFWriter::EmitGlobal(GlobalVariable *GV, ELFSection &DataSection, SymbolTable.push_back(ExternalSym); return; } - + const Type *GVType = (const Type*)GV->getType(); - unsigned Align = TM.getTargetData().getTypeAlignment(GVType); - unsigned Size = TM.getTargetData().getTypeSize(GVType); + unsigned Align = TM.getTargetData()->getPreferredAlignment(GV); + unsigned Size = TM.getTargetData()->getABITypeSize(GVType); // If this global has a zero initializer, it is part of the .bss or common // section. @@ -244,7 +282,8 @@ void ELFWriter::EmitGlobal(GlobalVariable *GV, ELFSection &DataSection, // If this global is part of the common block, add it now. Variables are // part of the common block if they are zero initialized and allowed to be // merged with other symbols. - if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage()) { + if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage() || + GV->hasCommonLinkage()) { ELFSym CommonSym(GV); // Value for common symbols is the alignment required. CommonSym.Value = Align; @@ -261,6 +300,7 @@ void ELFWriter::EmitGlobal(GlobalVariable *GV, ELFSection &DataSection, // Handle alignment. Ensure section is aligned at least as much as required // by this symbol. + ELFSection &BSSSection = getBSSSection(); BSSSection.Align = std::max(BSSSection.Align, Align); // Within the section, emit enough virtual padding to get us to an alignment @@ -274,7 +314,7 @@ void ELFWriter::EmitGlobal(GlobalVariable *GV, ELFSection &DataSection, BSSSym.SetType(ELFSym::STT_OBJECT); switch (GV->getLinkage()) { - default: // weak/linkonce handled above + default: // weak/linkonce/common handled above assert(0 && "Unexpected linkage type!"); case GlobalValue::AppendingLinkage: // FIXME: This should be improved! case GlobalValue::ExternalLinkage: @@ -286,7 +326,7 @@ 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 +350,11 @@ 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. - 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; - 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); + EmitGlobal(I); // Emit the symbol table now, if non-empty. EmitSymbolTable(); @@ -353,14 +364,12 @@ 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 .o file to the specified stream. - O.write((char*)&OutputBuffer[0], OutputBuffer.size()); + // Emit the sections to the .o file, and emit the section table for the file. + OutputSectionsAndSectionTable(); - // Free the output buffer. - std::vector().swap(OutputBuffer); + // We are done with the abstract symbols. + SectionList.clear(); + NumSections = 0; // Release the name mangler object. delete Mang; Mang = 0; @@ -375,13 +384,14 @@ 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(); - StrTab.Type = ELFSection::SHT_STRTAB; + ELFSection &StrTab = getSection(".strtab", ELFSection::SHT_STRTAB, 0); StrTab.Align = 1; + DataBuffer &StrTabBuf = StrTab.SectionData; + OutputBuffer StrTabOut(StrTabBuf, is64Bit, isLittleEndian); + // Set the zero'th symbol to a null byte, as required. - outbyte(0); + StrTabOut.outbyte(0); SymbolTable[0].NameIdx = 0; unsigned Index = 1; for (unsigned i = 1, e = SymbolTable.size(); i != e; ++i) { @@ -394,44 +404,51 @@ 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. - assert(!is64Bit && "Should this be 8 byte aligned for 64-bit?" - " (check .Align below also)"); - align(4); - - SectionList.push_back(ELFSection(".symtab", OutputBuffer.size())); - ELFSection &SymTab = SectionList.back(); - SymTab.Type = ELFSection::SHT_SYMTAB; - SymTab.Align = 4; // FIXME: check for ELF64 - SymTab.Link = SectionList.size()-2; // Section Index of .strtab. + ELFSection &SymTab = getSection(".symtab", ELFSection::SHT_SYMTAB, 0); + SymTab.Align = is64Bit ? 8 : 4; + 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 - - assert(!is64Bit && "check this!"); - for (unsigned i = 0, e = SymbolTable.size(); i != e; ++i) { - ELFSym &Sym = SymbolTable[i]; - outword(Sym.NameIdx); - outaddr(Sym.Value); - outword(Sym.Size); - outbyte(Sym.Info); - outbyte(Sym.Other); - outhalf(Sym.SectionIdx); + DataBuffer &SymTabBuf = SymTab.SectionData; + OutputBuffer SymTabOut(SymTabBuf, is64Bit, isLittleEndian); + + 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]; + SymTabOut.outword(Sym.NameIdx); + SymTabOut.outaddr32(Sym.Value); + SymTabOut.outword(Sym.Size); + SymTabOut.outbyte(Sym.Info); + SymTabOut.outbyte(Sym.Other); + SymTabOut.outhalf(Sym.SectionIdx); + } + } else { + for (unsigned i = 0, e = SymbolTable.size(); i != e; ++i) { + ELFSym &Sym = SymbolTable[i]; + SymTabOut.outword(Sym.NameIdx); + SymTabOut.outbyte(Sym.Info); + SymTabOut.outbyte(Sym.Other); + SymTabOut.outhalf(Sym.SectionIdx); + SymTabOut.outaddr64(Sym.Value); + SymTabOut.outxword(Sym.Size); + } } - SymTab.Size = OutputBuffer.size()-SymTab.Offset; + SymTab.Size = SymTabBuf.size(); } /// EmitSectionTableStringTable - This method adds and emits a section for the @@ -439,63 +456,109 @@ 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", ELFSection::SHT_STRTAB, 0); // 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); + OutputBuffer FHOut(FileHeader, is64Bit, isLittleEndian); + FHOut.fixhalf(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::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); - - // 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); - - // 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. +/// 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::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(); } - // Release the memory allocated for the section list. - std::vector().swap(SectionList); + // 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. + OutputBuffer FHOut(FileHeader, is64Bit, isLittleEndian); + FHOut.fixhalf(NumSections, ELFHeader_e_shnum_Offset); + + // Now that we know the offset in the file of the section table, update the + // e_shoff address in the ELF header. + FHOut.fixaddr(FileOff, ELFHeader_e_shoff_Offset); + + // 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; + OutputBuffer TableOut(Table, is64Bit, isLittleEndian); + + // 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((char)0xAB); + O.write((char*)&S.SectionData[0], S.SectionData.size()); + FileOff += S.SectionData.size(); + + TableOut.outword(S.NameIdx); // sh_name - Symbol table name idx + TableOut.outword(S.Type); // sh_type - Section contents & semantics + TableOut.outword(S.Flags); // sh_flags - Section flags. + TableOut.outaddr(S.Addr); // sh_addr - The mem addr this section is in. + TableOut.outaddr(S.Offset); // sh_offset - Offset from the file start. + TableOut.outword(S.Size); // sh_size - The section size. + TableOut.outword(S.Link); // sh_link - Section header table index link. + TableOut.outword(S.Info); // sh_info - Auxillary information. + TableOut.outword(S.Align); // sh_addralign - Alignment of section. + TableOut.outword(S.EntSize); // sh_entsize - Size of entries in the section + + SectionList.pop_front(); + } + + // Align output for the section table. + for (size_t NewFileOff = (FileOff+TableAlign-1) & ~(TableAlign-1); + FileOff != NewFileOff; ++FileOff) + O.put((char)0xAB); + + // Emit the section table itself. + O.write((char*)&Table[0], Table.size()); }