X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FELFWriter.cpp;h=f2c218565854c3833c68ce802190bcb2ad9dd056;hb=1b3f9198ab3880be34b6252423b9e388b5cd6a5e;hp=683a21e5e493b1256150056911f8f1a4f99c01c2;hpb=64f03003a1cf9fb8f8b068da7fa66a58e86ad390;p=oota-llvm.git diff --git a/lib/CodeGen/ELFWriter.cpp b/lib/CodeGen/ELFWriter.cpp index 683a21e5e49..f2c21856585 100644 --- a/lib/CodeGen/ELFWriter.cpp +++ b/lib/CodeGen/ELFWriter.cpp @@ -26,431 +26,974 @@ // ... // #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! -// //===----------------------------------------------------------------------===// +#define DEBUG_TYPE "elfwriter" +#include "ELF.h" #include "ELFWriter.h" +#include "ELFCodeEmitter.h" +#include "llvm/Constants.h" #include "llvm/Module.h" #include "llvm/PassManager.h" -#include "llvm/Type.h" // FIXME: For PATypeHolder::get(). -#include "llvm/CodeGen/FileWriters.h" +#include "llvm/DerivedTypes.h" +#include "llvm/CodeGen/BinaryObject.h" +#include "llvm/CodeGen/MachineCodeEmitter.h" +#include "llvm/CodeGen/ObjectCodeEmitter.h" #include "llvm/CodeGen/MachineCodeEmitter.h" #include "llvm/CodeGen/MachineConstantPool.h" -#include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/MC/MCContext.h" +#include "llvm/MC/MCSectionELF.h" +#include "llvm/MC/MCAsmInfo.h" +#include "llvm/Target/Mangler.h" #include "llvm/Target/TargetData.h" #include "llvm/Target/TargetELFWriterInfo.h" +#include "llvm/Target/TargetLowering.h" +#include "llvm/Target/TargetLoweringObjectFile.h" #include "llvm/Target/TargetMachine.h" -#include "llvm/Support/Mangler.h" -#include "llvm/Support/OutputBuffer.h" -#include "llvm/Support/Streams.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" #include "llvm/Support/raw_ostream.h" -#include +#include "llvm/ADT/SmallString.h" 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, - raw_ostream &O, - TargetMachine &TM) { - ELFWriter *EW = new ELFWriter(O, TM); - PM.add(EW); - return &EW->getMachineCodeEmitter(); -} //===----------------------------------------------------------------------===// -// ELFCodeEmitter Implementation +// ELFWriter Implementation //===----------------------------------------------------------------------===// -namespace llvm { - /// ELFCodeEmitter - This class is used by the ELFWriter to emit the code for - /// functions to the ELF file. - class ELFCodeEmitter : public MachineCodeEmitter { - ELFWriter &EW; - TargetMachine &TM; - ELFWriter::ELFSection *ES; // Section to write to. - std::vector *OutBuffer; - size_t FnStart; - public: - explicit ELFCodeEmitter(ELFWriter &ew) : EW(ew), TM(EW.TM), OutBuffer(0) {} - - void startFunction(MachineFunction &F); - bool finishFunction(MachineFunction &F); - - void addRelocation(const MachineRelocation &MR) { - assert(0 && "relo not handled yet!"); - } - - virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) { - } +ELFWriter::ELFWriter(raw_ostream &o, TargetMachine &tm) + : MachineFunctionPass(ID), O(o), TM(tm), + OutContext(*new MCContext(*TM.getMCAsmInfo(), *TM.getRegisterInfo(), + &TM.getTargetLowering()->getObjFileLowering())), + TLOF(TM.getTargetLowering()->getObjFileLowering()), + is64Bit(TM.getTargetData()->getPointerSizeInBits() == 64), + isLittleEndian(TM.getTargetData()->isLittleEndian()), + ElfHdr(isLittleEndian, is64Bit) { - virtual uintptr_t getConstantPoolEntryAddress(unsigned Index) const { - assert(0 && "CP not implementated yet!"); - return 0; - } - virtual uintptr_t getJumpTableEntryAddress(unsigned Index) const { - assert(0 && "JT not implementated yet!"); - return 0; - } + MAI = TM.getMCAsmInfo(); + TEW = TM.getELFWriterInfo(); - virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const { - assert(0 && "JT not implementated yet!"); - return 0; - } + // Create the object code emitter object for this target. + ElfCE = new ELFCodeEmitter(*this); - virtual uintptr_t getLabelAddress(uint64_t Label) const { - assert(0 && "Label address not implementated yet!"); - abort(); - return 0; - } + // Initial number of sections + NumSections = 0; +} - virtual void emitLabel(uint64_t LabelID) { - assert(0 && "emit Label not implementated yet!"); - abort(); - } +ELFWriter::~ELFWriter() { + delete ElfCE; + delete &OutContext; + while(!SymbolList.empty()) { + delete SymbolList.back(); + SymbolList.pop_back(); + } - virtual void setModuleInfo(llvm::MachineModuleInfo* MMI) { } + while(!PrivateSyms.empty()) { + delete PrivateSyms.back(); + PrivateSyms.pop_back(); + } + while(!SectionList.empty()) { + delete SectionList.back(); + SectionList.pop_back(); + } - /// JIT SPECIFIC FUNCTIONS - DO NOT IMPLEMENT THESE HERE! - void startGVStub(const GlobalValue* F, unsigned StubSize, - unsigned Alignment = 1) { - assert(0 && "JIT specific function called!"); - abort(); - } - void *finishGVStub(const GlobalValue *F) { - assert(0 && "JIT specific function called!"); - abort(); - return 0; - } - }; -} - -/// startFunction - This callback is invoked when a new machine function is -/// about to be emitted. -void ELFCodeEmitter::startFunction(MachineFunction &F) { - // Align the output buffer to the appropriate alignment. - unsigned Align = 16; // FIXME: GENERICIZE!! - // 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 (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. - 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. -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: - // appending linkage is illegal for functions. - assert(0 && "Unknown linkage type!"); - case GlobalValue::ExternalLinkage: - FnSym.SetBind(ELFWriter::ELFSym::STB_GLOBAL); - break; - case GlobalValue::LinkOnceLinkage: - case GlobalValue::WeakLinkage: - FnSym.SetBind(ELFWriter::ELFSym::STB_WEAK); - break; - case GlobalValue::InternalLinkage: - FnSym.SetBind(ELFWriter::ELFSym::STB_LOCAL); + // Release the name mangler object. + delete Mang; Mang = 0; +} + +// doInitialization - Emit the file header and all of the global variables for +// the module to the ELF file. +bool ELFWriter::doInitialization(Module &M) { + // Initialize TargetLoweringObjectFile. + const_cast(TLOF).Initialize(OutContext, TM); + + Mang = new Mangler(OutContext, *TM.getTargetData()); + + // ELF Header + // ---------- + // Fields e_shnum e_shstrndx are only known after all section have + // been emitted. They locations in the ouput buffer are recorded so + // to be patched up later. + // + // Note + // ---- + // emitWord method behaves differently for ELF32 and ELF64, writing + // 4 bytes in the former and 8 in the last for *_off and *_addr elf types + + ElfHdr.emitByte(0x7f); // e_ident[EI_MAG0] + ElfHdr.emitByte('E'); // e_ident[EI_MAG1] + ElfHdr.emitByte('L'); // e_ident[EI_MAG2] + ElfHdr.emitByte('F'); // e_ident[EI_MAG3] + + ElfHdr.emitByte(TEW->getEIClass()); // e_ident[EI_CLASS] + ElfHdr.emitByte(TEW->getEIData()); // e_ident[EI_DATA] + ElfHdr.emitByte(ELF::EV_CURRENT); // e_ident[EI_VERSION] + ElfHdr.emitAlignment(16); // e_ident[EI_NIDENT-EI_PAD] + + ElfHdr.emitWord16(ELF::ET_REL); // e_type + ElfHdr.emitWord16(TEW->getEMachine()); // e_machine = target + ElfHdr.emitWord32(ELF::EV_CURRENT); // e_version + ElfHdr.emitWord(0); // e_entry, no entry point in .o file + ElfHdr.emitWord(0); // e_phoff, no program header for .o + ELFHdr_e_shoff_Offset = ElfHdr.size(); + ElfHdr.emitWord(0); // e_shoff = sec hdr table off in bytes + ElfHdr.emitWord32(TEW->getEFlags()); // e_flags = whatever the target wants + ElfHdr.emitWord16(TEW->getHdrSize()); // e_ehsize = ELF header size + ElfHdr.emitWord16(0); // e_phentsize = prog header entry size + ElfHdr.emitWord16(0); // e_phnum = # prog header entries = 0 + + // e_shentsize = Section header entry size + ElfHdr.emitWord16(TEW->getSHdrSize()); + + // e_shnum = # of section header ents + ELFHdr_e_shnum_Offset = ElfHdr.size(); + ElfHdr.emitWord16(0); // Placeholder + + // e_shstrndx = Section # of '.shstrtab' + ELFHdr_e_shstrndx_Offset = ElfHdr.size(); + ElfHdr.emitWord16(0); // Placeholder + + // Add the null section, which is required to be first in the file. + getNullSection(); + + // The first entry in the symtab is the null symbol and the second + // is a local symbol containing the module/file name + SymbolList.push_back(new ELFSym()); + SymbolList.push_back(ELFSym::getFileSym()); + + return false; +} + +// AddPendingGlobalSymbol - Add a global to be processed and to +// the global symbol lookup, use a zero index because the table +// index will be determined later. +void ELFWriter::AddPendingGlobalSymbol(const GlobalValue *GV, + bool AddToLookup /* = false */) { + PendingGlobals.insert(GV); + if (AddToLookup) + GblSymLookup[GV] = 0; +} + +// AddPendingExternalSymbol - Add the external to be processed +// and to the external symbol lookup, use a zero index because +// the symbol table index will be determined later. +void ELFWriter::AddPendingExternalSymbol(const char *External) { + PendingExternals.insert(External); + ExtSymLookup[External] = 0; +} + +ELFSection &ELFWriter::getDataSection() { + const MCSectionELF *Data = (const MCSectionELF *)TLOF.getDataSection(); + return getSection(Data->getSectionName(), Data->getType(), + Data->getFlags(), 4); +} + +ELFSection &ELFWriter::getBSSSection() { + const MCSectionELF *BSS = (const MCSectionELF *)TLOF.getBSSSection(); + return getSection(BSS->getSectionName(), BSS->getType(), BSS->getFlags(), 4); +} + +// getCtorSection - Get the static constructor section +ELFSection &ELFWriter::getCtorSection() { + const MCSectionELF *Ctor = (const MCSectionELF *)TLOF.getStaticCtorSection(); + return getSection(Ctor->getSectionName(), Ctor->getType(), Ctor->getFlags()); +} + +// getDtorSection - Get the static destructor section +ELFSection &ELFWriter::getDtorSection() { + const MCSectionELF *Dtor = (const MCSectionELF *)TLOF.getStaticDtorSection(); + return getSection(Dtor->getSectionName(), Dtor->getType(), Dtor->getFlags()); +} + +// getTextSection - Get the text section for the specified function +ELFSection &ELFWriter::getTextSection(const Function *F) { + const MCSectionELF *Text = + (const MCSectionELF *)TLOF.SectionForGlobal(F, Mang, TM); + return getSection(Text->getSectionName(), Text->getType(), Text->getFlags()); +} + +// getJumpTableSection - Get a read only section for constants when +// emitting jump tables. TODO: add PIC support +ELFSection &ELFWriter::getJumpTableSection() { + const MCSectionELF *JT = + (const MCSectionELF *)TLOF.getSectionForConstant(SectionKind::getReadOnly()); + return getSection(JT->getSectionName(), JT->getType(), JT->getFlags(), + TM.getTargetData()->getPointerABIAlignment()); +} + +// getConstantPoolSection - Get a constant pool section based on the machine +// constant pool entry type and relocation info. +ELFSection &ELFWriter::getConstantPoolSection(MachineConstantPoolEntry &CPE) { + SectionKind Kind; + switch (CPE.getRelocationInfo()) { + default: llvm_unreachable("Unknown section kind"); + case 2: Kind = SectionKind::getReadOnlyWithRel(); break; + case 1: + Kind = SectionKind::getReadOnlyWithRelLocal(); break; + case 0: + switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) { + case 4: Kind = SectionKind::getMergeableConst4(); break; + case 8: Kind = SectionKind::getMergeableConst8(); break; + case 16: Kind = SectionKind::getMergeableConst16(); break; + default: Kind = SectionKind::getMergeableConst(); break; + } } - ES->Size = OutBuffer->size(); + const MCSectionELF *CPSect = + (const MCSectionELF *)TLOF.getSectionForConstant(Kind); + return getSection(CPSect->getSectionName(), CPSect->getType(), + CPSect->getFlags(), CPE.getAlignment()); +} - FnSym.SetType(ELFWriter::ELFSym::STT_FUNC); - FnSym.SectionIdx = ES->SectionIdx; - FnSym.Value = FnStart; // Value = Offset from start of Section. - FnSym.Size = OutBuffer->size()-FnStart; +// getRelocSection - Return the relocation section of section 'S'. 'RelA' +// is true if the relocation section contains entries with addends. +ELFSection &ELFWriter::getRelocSection(ELFSection &S) { + unsigned SectionType = TEW->hasRelocationAddend() ? + ELF::SHT_RELA : ELF::SHT_REL; - // Finally, add it to the symtab. - EW.SymbolTable.push_back(FnSym); - return false; + std::string SectionName(".rel"); + if (TEW->hasRelocationAddend()) + SectionName.append("a"); + SectionName.append(S.getName()); + + return getSection(SectionName, SectionType, 0, TEW->getPrefELFAlignment()); } -//===----------------------------------------------------------------------===// -// ELFWriter Implementation -//===----------------------------------------------------------------------===// +// getGlobalELFVisibility - Returns the ELF specific visibility type +unsigned ELFWriter::getGlobalELFVisibility(const GlobalValue *GV) { + switch (GV->getVisibility()) { + default: + llvm_unreachable("unknown visibility type"); + case GlobalValue::DefaultVisibility: + return ELF::STV_DEFAULT; + case GlobalValue::HiddenVisibility: + return ELF::STV_HIDDEN; + case GlobalValue::ProtectedVisibility: + return ELF::STV_PROTECTED; + } + return 0; +} -ELFWriter::ELFWriter(raw_ostream &o, TargetMachine &tm) - : MachineFunctionPass(&ID), O(o), TM(tm) { - e_flags = 0; // e_flags defaults to 0, no flags. +// getGlobalELFBinding - Returns the ELF specific binding type +unsigned ELFWriter::getGlobalELFBinding(const GlobalValue *GV) { + if (GV->hasInternalLinkage()) + return ELF::STB_LOCAL; - is64Bit = TM.getTargetData()->getPointerSizeInBits() == 64; - isLittleEndian = TM.getTargetData()->isLittleEndian(); + if (GV->isWeakForLinker() && !GV->hasCommonLinkage()) + return ELF::STB_WEAK; - // Create the machine code emitter object for this target. - MCE = new ELFCodeEmitter(*this); - NumSections = 0; + return ELF::STB_GLOBAL; } -ELFWriter::~ELFWriter() { - delete MCE; +// getGlobalELFType - Returns the ELF specific type for a global +unsigned ELFWriter::getGlobalELFType(const GlobalValue *GV) { + if (GV->isDeclaration()) + return ELF::STT_NOTYPE; + + if (isa(GV)) + return ELF::STT_FUNC; + + return ELF::STT_OBJECT; } -// doInitialization - Emit the file header and all of the global variables for -// the module to the ELF file. -bool ELFWriter::doInitialization(Module &M) { - Mang = new Mangler(M); - - // 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. - 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' +// IsELFUndefSym - True if the global value must be marked as a symbol +// which points to a SHN_UNDEF section. This means that the symbol has +// no definition on the module. +static bool IsELFUndefSym(const GlobalValue *GV) { + return GV->isDeclaration() || (isa(GV)); +} - // Add the null section, which is required to be first in the file. - getSection("", 0, 0); +// AddToSymbolList - Update the symbol lookup and If the symbol is +// private add it to PrivateSyms list, otherwise to SymbolList. +void ELFWriter::AddToSymbolList(ELFSym *GblSym) { + assert(GblSym->isGlobalValue() && "Symbol must be a global value"); + + const GlobalValue *GV = GblSym->getGlobalValue(); + if (GV->hasPrivateLinkage()) { + // For a private symbols, keep track of the index inside + // the private list since it will never go to the symbol + // table and won't be patched up later. + PrivateSyms.push_back(GblSym); + GblSymLookup[GV] = PrivateSyms.size()-1; + } else { + // Non private symbol are left with zero indices until + // they are patched up during the symbol table emition + // (where the indicies are created). + SymbolList.push_back(GblSym); + GblSymLookup[GV] = 0; + } +} - // Start up the symbol table. The first entry in the symtab is the null - // entry. - SymbolTable.push_back(ELFSym(0)); +/// HasCommonSymbols - True if this section holds common symbols, this is +/// indicated on the ELF object file by a symbol with SHN_COMMON section +/// header index. +static bool HasCommonSymbols(const MCSectionELF &S) { + // FIXME: this is wrong, a common symbol can be in .data for example. + if (StringRef(S.getSectionName()).startswith(".gnu.linkonce.")) + return true; return false; } -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. - if (!GV->hasInitializer()) { - ELFSym ExternalSym(GV); - ExternalSym.SetBind(ELFSym::STB_GLOBAL); - ExternalSym.SetType(ELFSym::STT_NOTYPE); - ExternalSym.SectionIdx = ELFSection::SHN_UNDEF; - SymbolTable.push_back(ExternalSym); + +// EmitGlobal - Choose the right section for global and emit it +void ELFWriter::EmitGlobal(const GlobalValue *GV) { + + // Check if the referenced symbol is already emitted + if (GblSymLookup.find(GV) != GblSymLookup.end()) return; - } - const Type *GVType = (const Type*)GV->getType(); - 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. - if (GV->getInitializer()->isNullValue()) { - // 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() || - GV->hasCommonLinkage()) { - ELFSym CommonSym(GV); - // Value for common symbols is the alignment required. - CommonSym.Value = Align; - CommonSym.Size = Size; - CommonSym.SetBind(ELFSym::STB_GLOBAL); - CommonSym.SetType(ELFSym::STT_OBJECT); - // TODO SOMEDAY: add ELF visibility. - CommonSym.SectionIdx = ELFSection::SHN_COMMON; - SymbolTable.push_back(CommonSym); + // Handle ELF Bind, Visibility and Type for the current symbol + unsigned SymBind = getGlobalELFBinding(GV); + unsigned SymType = getGlobalELFType(GV); + bool IsUndefSym = IsELFUndefSym(GV); + + ELFSym *GblSym = IsUndefSym ? ELFSym::getUndefGV(GV, SymBind) + : ELFSym::getGV(GV, SymBind, SymType, getGlobalELFVisibility(GV)); + + if (!IsUndefSym) { + assert(isa(GV) && "GV not a global variable!"); + const GlobalVariable *GVar = dyn_cast(GV); + + // Handle special llvm globals + if (EmitSpecialLLVMGlobal(GVar)) return; - } - // Otherwise, this symbol is part of the .bss section. Emit it now. - - // 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 - // boundary. - if (Align) - BSSSection.Size = (BSSSection.Size + Align - 1) & ~(Align-1); - - ELFSym BSSSym(GV); - BSSSym.Value = BSSSection.Size; - BSSSym.Size = Size; - BSSSym.SetType(ELFSym::STT_OBJECT); - - switch (GV->getLinkage()) { - default: // weak/linkonce/common handled above - assert(0 && "Unexpected linkage type!"); - case GlobalValue::AppendingLinkage: // FIXME: This should be improved! - case GlobalValue::ExternalLinkage: - BSSSym.SetBind(ELFSym::STB_GLOBAL); - break; - case GlobalValue::InternalLinkage: - BSSSym.SetBind(ELFSym::STB_LOCAL); - break; + // Get the ELF section where this global belongs from TLOF + const MCSectionELF *S = + (const MCSectionELF *)TLOF.SectionForGlobal(GV, Mang, TM); + ELFSection &ES = + getSection(S->getSectionName(), S->getType(), S->getFlags()); + SectionKind Kind = S->getKind(); + + // The symbol align should update the section alignment if needed + const TargetData *TD = TM.getTargetData(); + unsigned Align = TD->getPreferredAlignment(GVar); + unsigned Size = TD->getTypeAllocSize(GVar->getInitializer()->getType()); + GblSym->Size = Size; + + if (HasCommonSymbols(*S)) { // Symbol must go to a common section + GblSym->SectionIdx = ELF::SHN_COMMON; + + // A new linkonce section is created for each global in the + // common section, the default alignment is 1 and the symbol + // value contains its alignment. + ES.Align = 1; + GblSym->Value = Align; + + } else if (Kind.isBSS() || Kind.isThreadBSS()) { // Symbol goes to BSS. + GblSym->SectionIdx = ES.SectionIdx; + + // Update the size with alignment and the next object can + // start in the right offset in the section + if (Align) ES.Size = (ES.Size + Align-1) & ~(Align-1); + ES.Align = std::max(ES.Align, Align); + + // GblSym->Value should contain the virtual offset inside the section. + // Virtual because the BSS space is not allocated on ELF objects + GblSym->Value = ES.Size; + ES.Size += Size; + + } else { // The symbol must go to some kind of data section + GblSym->SectionIdx = ES.SectionIdx; + + // GblSym->Value should contain the symbol offset inside the section, + // and all symbols should start on their required alignment boundary + ES.Align = std::max(ES.Align, Align); + ES.emitAlignment(Align); + GblSym->Value = ES.size(); + + // Emit the global to the data section 'ES' + EmitGlobalConstant(GVar->getInitializer(), ES); } + } + + AddToSymbolList(GblSym); +} + +void ELFWriter::EmitGlobalConstantStruct(const ConstantStruct *CVS, + ELFSection &GblS) { + + // Print the fields in successive locations. Pad to align if needed! + const TargetData *TD = TM.getTargetData(); + unsigned Size = TD->getTypeAllocSize(CVS->getType()); + const StructLayout *cvsLayout = TD->getStructLayout(CVS->getType()); + uint64_t sizeSoFar = 0; + for (unsigned i = 0, e = CVS->getNumOperands(); i != e; ++i) { + const Constant* field = CVS->getOperand(i); + + // Check if padding is needed and insert one or more 0s. + uint64_t fieldSize = TD->getTypeAllocSize(field->getType()); + uint64_t padSize = ((i == e-1 ? Size : cvsLayout->getElementOffset(i+1)) + - cvsLayout->getElementOffset(i)) - fieldSize; + sizeSoFar += fieldSize + padSize; + + // Now print the actual field value. + EmitGlobalConstant(field, GblS); + + // Insert padding - this may include padding to increase the size of the + // current field up to the ABI size (if the struct is not packed) as well + // as padding to ensure that the next field starts at the right offset. + GblS.emitZeros(padSize); + } + assert(sizeSoFar == cvsLayout->getSizeInBytes() && + "Layout of constant struct may be incorrect!"); +} + +void ELFWriter::EmitGlobalConstant(const Constant *CV, ELFSection &GblS) { + const TargetData *TD = TM.getTargetData(); + unsigned Size = TD->getTypeAllocSize(CV->getType()); - // Set the idx of the .bss section - BSSSym.SectionIdx = BSSSection.SectionIdx; - SymbolTable.push_back(BSSSym); + if (const ConstantArray *CVA = dyn_cast(CV)) { + for (unsigned i = 0, e = CVA->getNumOperands(); i != e; ++i) + EmitGlobalConstant(CVA->getOperand(i), GblS); + return; + } else if (isa(CV)) { + GblS.emitZeros(Size); + return; + } else if (const ConstantStruct *CVS = dyn_cast(CV)) { + EmitGlobalConstantStruct(CVS, GblS); + return; + } else if (const ConstantFP *CFP = dyn_cast(CV)) { + APInt Val = CFP->getValueAPF().bitcastToAPInt(); + if (CFP->getType()->isDoubleTy()) + GblS.emitWord64(Val.getZExtValue()); + else if (CFP->getType()->isFloatTy()) + GblS.emitWord32(Val.getZExtValue()); + else if (CFP->getType()->isX86_FP80Ty()) { + unsigned PadSize = TD->getTypeAllocSize(CFP->getType())- + TD->getTypeStoreSize(CFP->getType()); + GblS.emitWordFP80(Val.getRawData(), PadSize); + } else if (CFP->getType()->isPPC_FP128Ty()) + llvm_unreachable("PPC_FP128Ty global emission not implemented"); + return; + } else if (const ConstantInt *CI = dyn_cast(CV)) { + if (Size == 1) + GblS.emitByte(CI->getZExtValue()); + else if (Size == 2) + GblS.emitWord16(CI->getZExtValue()); + else if (Size == 4) + GblS.emitWord32(CI->getZExtValue()); + else + EmitGlobalConstantLargeInt(CI, GblS); + return; + } else if (const ConstantVector *CP = dyn_cast(CV)) { + VectorType *PTy = CP->getType(); + for (unsigned I = 0, E = PTy->getNumElements(); I < E; ++I) + EmitGlobalConstant(CP->getOperand(I), GblS); + return; + } else if (const ConstantExpr *CE = dyn_cast(CV)) { + // Resolve a constant expression which returns a (Constant, Offset) + // pair. If 'Res.first' is a GlobalValue, emit a relocation with + // the offset 'Res.second', otherwise emit a global constant like + // it is always done for not contant expression types. + CstExprResTy Res = ResolveConstantExpr(CE); + const Constant *Op = Res.first; + + if (isa(Op)) + EmitGlobalDataRelocation(cast(Op), + TD->getTypeAllocSize(Op->getType()), + GblS, Res.second); + else + EmitGlobalConstant(Op, GblS); - // Reserve space in the .bss section for this symbol. - BSSSection.Size += Size; return; + } else if (CV->getType()->getTypeID() == Type::PointerTyID) { + // Fill the data entry with zeros or emit a relocation entry + if (isa(CV)) + GblS.emitZeros(Size); + else + EmitGlobalDataRelocation(cast(CV), + Size, GblS); + return; + } else if (const GlobalValue *GV = dyn_cast(CV)) { + // This is a constant address for a global variable or function and + // therefore must be referenced using a relocation entry. + EmitGlobalDataRelocation(GV, Size, GblS); + return; + } + + std::string msg; + raw_string_ostream ErrorMsg(msg); + ErrorMsg << "Constant unimp for type: " << *CV->getType(); + report_fatal_error(ErrorMsg.str()); +} + +// ResolveConstantExpr - Resolve the constant expression until it stop +// yielding other constant expressions. +CstExprResTy ELFWriter::ResolveConstantExpr(const Constant *CV) { + const TargetData *TD = TM.getTargetData(); + + // There ins't constant expression inside others anymore + if (!isa(CV)) + return std::make_pair(CV, 0); + + const ConstantExpr *CE = dyn_cast(CV); + switch (CE->getOpcode()) { + case Instruction::BitCast: + return ResolveConstantExpr(CE->getOperand(0)); + + case Instruction::GetElementPtr: { + const Constant *ptrVal = CE->getOperand(0); + SmallVector idxVec(CE->op_begin()+1, CE->op_end()); + int64_t Offset = TD->getIndexedOffset(ptrVal->getType(), idxVec); + return std::make_pair(ptrVal, Offset); + } + case Instruction::IntToPtr: { + Constant *Op = CE->getOperand(0); + Op = ConstantExpr::getIntegerCast(Op, TD->getIntPtrType(CV->getContext()), + false/*ZExt*/); + return ResolveConstantExpr(Op); + } + case Instruction::PtrToInt: { + Constant *Op = CE->getOperand(0); + Type *Ty = CE->getType(); + + // We can emit the pointer value into this slot if the slot is an + // integer slot greater or equal to the size of the pointer. + if (TD->getTypeAllocSize(Ty) == TD->getTypeAllocSize(Op->getType())) + return ResolveConstantExpr(Op); + + llvm_unreachable("Integer size less then pointer size"); } + case Instruction::Add: + case Instruction::Sub: { + // Only handle cases where there's a constant expression with GlobalValue + // as first operand and ConstantInt as second, which are the cases we can + // solve direclty using a relocation entry. GlobalValue=Op0, CstInt=Op1 + // 1) Instruction::Add => (global) + CstInt + // 2) Instruction::Sub => (global) + -CstInt + const Constant *Op0 = CE->getOperand(0); + const Constant *Op1 = CE->getOperand(1); + assert(isa(Op1) && "Op1 must be a ConstantInt"); + + CstExprResTy Res = ResolveConstantExpr(Op0); + assert(isa(Res.first) && "Op0 must be a GlobalValue"); + + const APInt &RHS = cast(Op1)->getValue(); + switch (CE->getOpcode()) { + case Instruction::Add: + return std::make_pair(Res.first, RHS.getSExtValue()); + case Instruction::Sub: + return std::make_pair(Res.first, (-RHS).getSExtValue()); + } + } + } + + report_fatal_error(CE->getOpcodeName() + + StringRef(": Unsupported ConstantExpr type")); + + return std::make_pair(CV, 0); // silence warning +} - // FIXME: handle .rodata - //assert(!GV->isConstant() && "unimp"); +void ELFWriter::EmitGlobalDataRelocation(const GlobalValue *GV, unsigned Size, + ELFSection &GblS, int64_t Offset) { + // Create the relocation entry for the global value + MachineRelocation MR = + MachineRelocation::getGV(GblS.getCurrentPCOffset(), + TEW->getAbsoluteLabelMachineRelTy(), + const_cast(GV), + Offset); - // FIXME: handle .data - //assert(0 && "unimp"); + // Fill the data entry with zeros + GblS.emitZeros(Size); + + // Add the relocation entry for the current data section + GblS.addRelocation(MR); } +void ELFWriter::EmitGlobalConstantLargeInt(const ConstantInt *CI, + ELFSection &S) { + const TargetData *TD = TM.getTargetData(); + unsigned BitWidth = CI->getBitWidth(); + assert(isPowerOf2_32(BitWidth) && + "Non-power-of-2-sized integers not handled!"); + + const uint64_t *RawData = CI->getValue().getRawData(); + uint64_t Val = 0; + for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) { + Val = (TD->isBigEndian()) ? RawData[e - i - 1] : RawData[i]; + S.emitWord64(Val); + } +} + +/// EmitSpecialLLVMGlobal - Check to see if the specified global is a +/// special global used by LLVM. If so, emit it and return true, otherwise +/// do nothing and return false. +bool ELFWriter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) { + if (GV->getName() == "llvm.used") + llvm_unreachable("not implemented yet"); + + // Ignore debug and non-emitted data. This handles llvm.compiler.used. + if (GV->getSection() == "llvm.metadata" || + GV->hasAvailableExternallyLinkage()) + return true; + + if (!GV->hasAppendingLinkage()) return false; + + assert(GV->hasInitializer() && "Not a special LLVM global!"); + + const TargetData *TD = TM.getTargetData(); + unsigned Align = TD->getPointerPrefAlignment(); + if (GV->getName() == "llvm.global_ctors") { + ELFSection &Ctor = getCtorSection(); + Ctor.emitAlignment(Align); + EmitXXStructorList(GV->getInitializer(), Ctor); + return true; + } + + if (GV->getName() == "llvm.global_dtors") { + ELFSection &Dtor = getDtorSection(); + Dtor.emitAlignment(Align); + EmitXXStructorList(GV->getInitializer(), Dtor); + return true; + } + + return false; +} + +/// EmitXXStructorList - Emit the ctor or dtor list. This just emits out the +/// function pointers, ignoring the init priority. +void ELFWriter::EmitXXStructorList(const Constant *List, ELFSection &Xtor) { + // Should be an array of '{ i32, void ()* }' structs. The first value is the + // init priority, which we ignore. + if (List->isNullValue()) return; + const ConstantArray *InitList = cast(List); + for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { + if (InitList->getOperand(i)->isNullValue()) + continue; + ConstantStruct *CS = cast(InitList->getOperand(i)); + + if (CS->getOperand(1)->isNullValue()) + continue; + + // Emit the function pointer. + EmitGlobalConstant(CS->getOperand(1), Xtor); + } +} bool ELFWriter::runOnMachineFunction(MachineFunction &MF) { - // Nothing to do here, this is all done through the MCE object above. + // Nothing to do here, this is all done through the ElfCE object above. return false; } /// doFinalization - Now that the module has been completely processed, emit /// the ELF file to 'O'. bool ELFWriter::doFinalization(Module &M) { - // Okay, the ELF header and .text sections have been completed, build the - // .data, .bss, and "common" sections next. + // Emit .data section placeholder + getDataSection(); + + // Emit .bss section placeholder + getBSSSection(); + + // Build and emit data, bss and "common" sections. for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I) EmitGlobal(I); + // Emit all pending globals + for (PendingGblsIter I = PendingGlobals.begin(), E = PendingGlobals.end(); + I != E; ++I) + EmitGlobal(*I); + + // Emit all pending externals + for (PendingExtsIter I = PendingExternals.begin(), E = PendingExternals.end(); + I != E; ++I) + SymbolList.push_back(ELFSym::getExtSym(*I)); + + // Emit a symbol for each section created until now, skip null section + for (unsigned i = 1, e = SectionList.size(); i < e; ++i) { + ELFSection &ES = *SectionList[i]; + ELFSym *SectionSym = ELFSym::getSectionSym(); + SectionSym->SectionIdx = ES.SectionIdx; + SymbolList.push_back(SectionSym); + ES.Sym = SymbolList.back(); + } + + // Emit string table + EmitStringTable(M.getModuleIdentifier()); + // Emit the symbol table now, if non-empty. EmitSymbolTable(); - // FIXME: Emit the relocations now. + // Emit the relocation sections. + EmitRelocations(); - // Emit the string table for the sections in the ELF file we have. + // Emit the sections string table. EmitSectionTableStringTable(); - // Emit the sections to the .o file, and emit the section table for the file. + // Dump the sections and section table to the .o file. OutputSectionsAndSectionTable(); - // We are done with the abstract symbols. - SectionList.clear(); - NumSections = 0; - - // Release the name mangler object. - delete Mang; Mang = 0; return false; } -/// EmitSymbolTable - If the current symbol table is non-empty, emit the string -/// table for it and then the symbol table itself. -void ELFWriter::EmitSymbolTable() { - if (SymbolTable.size() == 1) return; // Only the null entry. +// RelocateField - Patch relocatable field with 'Offset' in 'BO' +// using a 'Value' of known 'Size' +void ELFWriter::RelocateField(BinaryObject &BO, uint32_t Offset, + int64_t Value, unsigned Size) { + if (Size == 32) + BO.fixWord32(Value, Offset); + else if (Size == 64) + BO.fixWord64(Value, Offset); + else + llvm_unreachable("don't know howto patch relocatable field"); +} + +/// EmitRelocations - Emit relocations +void ELFWriter::EmitRelocations() { + + // True if the target uses the relocation entry to hold the addend, + // otherwise the addend is written directly to the relocatable field. + bool HasRelA = TEW->hasRelocationAddend(); + + // Create Relocation sections for each section which needs it. + for (unsigned i=0, e=SectionList.size(); i != e; ++i) { + ELFSection &S = *SectionList[i]; + + // This section does not have relocations + if (!S.hasRelocations()) continue; + ELFSection &RelSec = getRelocSection(S); + + // 'Link' - Section hdr idx of the associated symbol table + // 'Info' - Section hdr idx of the section to which the relocation applies + ELFSection &SymTab = getSymbolTableSection(); + RelSec.Link = SymTab.SectionIdx; + RelSec.Info = S.SectionIdx; + RelSec.EntSize = TEW->getRelocationEntrySize(); + + // Get the relocations from Section + std::vector Relos = S.getRelocations(); + for (std::vector::iterator MRI = Relos.begin(), + MRE = Relos.end(); MRI != MRE; ++MRI) { + MachineRelocation &MR = *MRI; + + // Relocatable field offset from the section start + unsigned RelOffset = MR.getMachineCodeOffset(); + + // Symbol index in the symbol table + unsigned SymIdx = 0; + + // Target specific relocation field type and size + unsigned RelType = TEW->getRelocationType(MR.getRelocationType()); + unsigned RelTySize = TEW->getRelocationTySize(RelType); + int64_t Addend = 0; + + // There are several machine relocations types, and each one of + // them needs a different approach to retrieve the symbol table index. + if (MR.isGlobalValue()) { + const GlobalValue *G = MR.getGlobalValue(); + int64_t GlobalOffset = MR.getConstantVal(); + SymIdx = GblSymLookup[G]; + if (G->hasPrivateLinkage()) { + // If the target uses a section offset in the relocation: + // SymIdx + Addend = section sym for global + section offset + unsigned SectionIdx = PrivateSyms[SymIdx]->SectionIdx; + Addend = PrivateSyms[SymIdx]->Value + GlobalOffset; + SymIdx = SectionList[SectionIdx]->getSymbolTableIndex(); + } else { + Addend = TEW->getDefaultAddendForRelTy(RelType, GlobalOffset); + } + } else if (MR.isExternalSymbol()) { + const char *ExtSym = MR.getExternalSymbol(); + SymIdx = ExtSymLookup[ExtSym]; + Addend = TEW->getDefaultAddendForRelTy(RelType); + } else { + // Get the symbol index for the section symbol + unsigned SectionIdx = MR.getConstantVal(); + SymIdx = SectionList[SectionIdx]->getSymbolTableIndex(); + + // The symbol offset inside the section + int64_t SymOffset = (int64_t)MR.getResultPointer(); + + // For pc relative relocations where symbols are defined in the same + // section they are referenced, ignore the relocation entry and patch + // the relocatable field with the symbol offset directly. + if (S.SectionIdx == SectionIdx && TEW->isPCRelativeRel(RelType)) { + int64_t Value = TEW->computeRelocation(SymOffset, RelOffset, RelType); + RelocateField(S, RelOffset, Value, RelTySize); + continue; + } + + Addend = TEW->getDefaultAddendForRelTy(RelType, SymOffset); + } + + // The target without addend on the relocation symbol must be + // patched in the relocation place itself to contain the addend + // otherwise write zeros to make sure there is no garbage there + RelocateField(S, RelOffset, HasRelA ? 0 : Addend, RelTySize); + + // Get the relocation entry and emit to the relocation section + ELFRelocation Rel(RelOffset, SymIdx, RelType, HasRelA, Addend); + EmitRelocation(RelSec, Rel, HasRelA); + } + } +} - // FIXME: compact all local symbols to the start of the symtab. - unsigned FirstNonLocalSymbol = 1; +/// EmitRelocation - Write relocation 'Rel' to the relocation section 'Rel' +void ELFWriter::EmitRelocation(BinaryObject &RelSec, ELFRelocation &Rel, + bool HasRelA) { + RelSec.emitWord(Rel.getOffset()); + RelSec.emitWord(Rel.getInfo(is64Bit)); + if (HasRelA) + RelSec.emitWord(Rel.getAddend()); +} + +/// EmitSymbol - Write symbol 'Sym' to the symbol table 'SymbolTable' +void ELFWriter::EmitSymbol(BinaryObject &SymbolTable, ELFSym &Sym) { + if (is64Bit) { + SymbolTable.emitWord32(Sym.NameIdx); + SymbolTable.emitByte(Sym.Info); + SymbolTable.emitByte(Sym.Other); + SymbolTable.emitWord16(Sym.SectionIdx); + SymbolTable.emitWord64(Sym.Value); + SymbolTable.emitWord64(Sym.Size); + } else { + SymbolTable.emitWord32(Sym.NameIdx); + SymbolTable.emitWord32(Sym.Value); + SymbolTable.emitWord32(Sym.Size); + SymbolTable.emitByte(Sym.Info); + SymbolTable.emitByte(Sym.Other); + SymbolTable.emitWord16(Sym.SectionIdx); + } +} - ELFSection &StrTab = getSection(".strtab", ELFSection::SHT_STRTAB, 0); - StrTab.Align = 1; +/// EmitSectionHeader - Write section 'Section' header in 'SHdrTab' +/// Section Header Table +void ELFWriter::EmitSectionHeader(BinaryObject &SHdrTab, + const ELFSection &SHdr) { + SHdrTab.emitWord32(SHdr.NameIdx); + SHdrTab.emitWord32(SHdr.Type); + if (is64Bit) { + SHdrTab.emitWord64(SHdr.Flags); + SHdrTab.emitWord(SHdr.Addr); + SHdrTab.emitWord(SHdr.Offset); + SHdrTab.emitWord64(SHdr.Size); + SHdrTab.emitWord32(SHdr.Link); + SHdrTab.emitWord32(SHdr.Info); + SHdrTab.emitWord64(SHdr.Align); + SHdrTab.emitWord64(SHdr.EntSize); + } else { + SHdrTab.emitWord32(SHdr.Flags); + SHdrTab.emitWord(SHdr.Addr); + SHdrTab.emitWord(SHdr.Offset); + SHdrTab.emitWord32(SHdr.Size); + SHdrTab.emitWord32(SHdr.Link); + SHdrTab.emitWord32(SHdr.Info); + SHdrTab.emitWord32(SHdr.Align); + SHdrTab.emitWord32(SHdr.EntSize); + } +} - DataBuffer &StrTabBuf = StrTab.SectionData; - OutputBuffer StrTabOut(StrTabBuf, is64Bit, isLittleEndian); +/// EmitStringTable - If the current symbol table is non-empty, emit the string +/// table for it +void ELFWriter::EmitStringTable(const std::string &ModuleName) { + if (!SymbolList.size()) return; // Empty symbol table. + ELFSection &StrTab = getStringTableSection(); // Set the zero'th symbol to a null byte, as required. - StrTabOut.outbyte(0); - SymbolTable[0].NameIdx = 0; + StrTab.emitByte(0); + + // Walk on the symbol list and write symbol names into the string table. unsigned Index = 1; - for (unsigned i = 1, e = SymbolTable.size(); i != e; ++i) { - // Use the name mangler to uniquify the LLVM symbol. - std::string Name = Mang->getValueName(SymbolTable[i].GV); + for (ELFSymIter I=SymbolList.begin(), E=SymbolList.end(); I != E; ++I) { + ELFSym &Sym = *(*I); + + std::string Name; + if (Sym.isGlobalValue()) { + SmallString<40> NameStr; + Mang->getNameWithPrefix(NameStr, Sym.getGlobalValue(), false); + Name.append(NameStr.begin(), NameStr.end()); + } else if (Sym.isExternalSym()) + Name.append(Sym.getExternalSymbol()); + else if (Sym.isFileType()) + Name.append(ModuleName); if (Name.empty()) { - SymbolTable[i].NameIdx = 0; + Sym.NameIdx = 0; } else { - SymbolTable[i].NameIdx = Index; - - // Add the name to the output buffer, including the null terminator. - StrTabBuf.insert(StrTabBuf.end(), Name.begin(), Name.end()); - - // Add a null terminator. - StrTabBuf.push_back(0); + Sym.NameIdx = Index; + StrTab.emitString(Name); // Keep track of the number of bytes emitted to this section. Index += Name.size()+1; } } - assert(Index == StrTabBuf.size()); + assert(Index == StrTab.size()); StrTab.Size = Index; +} + +// SortSymbols - On the symbol table local symbols must come before +// all other symbols with non-local bindings. The return value is +// the position of the first non local symbol. +unsigned ELFWriter::SortSymbols() { + unsigned FirstNonLocalSymbol; + std::vector LocalSyms, OtherSyms; + + for (ELFSymIter I=SymbolList.begin(), E=SymbolList.end(); I != E; ++I) { + if ((*I)->isLocalBind()) + LocalSyms.push_back(*I); + else + OtherSyms.push_back(*I); + } + SymbolList.clear(); + FirstNonLocalSymbol = LocalSyms.size(); + + for (unsigned i = 0; i < FirstNonLocalSymbol; ++i) + SymbolList.push_back(LocalSyms[i]); + + for (ELFSymIter I=OtherSyms.begin(), E=OtherSyms.end(); I != E; ++I) + SymbolList.push_back(*I); + + LocalSyms.clear(); + OtherSyms.clear(); + + return FirstNonLocalSymbol; +} + +/// EmitSymbolTable - Emit the symbol table itself. +void ELFWriter::EmitSymbolTable() { + if (!SymbolList.size()) return; // Empty symbol table. // Now that we have emitted the string table and know the offset into the // string table of each symbol, emit the symbol table itself. - 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 - 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); - } + ELFSection &SymTab = getSymbolTableSection(); + SymTab.Align = TEW->getPrefELFAlignment(); + + // Section Index of .strtab. + SymTab.Link = getStringTableSection().SectionIdx; + + // Size of each symtab entry. + SymTab.EntSize = TEW->getSymTabEntrySize(); + + // Reorder the symbol table with local symbols first! + unsigned FirstNonLocalSymbol = SortSymbols(); + + // Emit all the symbols to the symbol table. + for (unsigned i = 0, e = SymbolList.size(); i < e; ++i) { + ELFSym &Sym = *SymbolList[i]; + + // Emit symbol to the symbol table + EmitSymbol(SymTab, Sym); + + // Record the symbol table index for each symbol + if (Sym.isGlobalValue()) + GblSymLookup[Sym.getGlobalValue()] = i; + else if (Sym.isExternalSym()) + ExtSymLookup[Sym.getExternalSymbol()] = i; + + // Keep track on the symbol index into the symbol table + Sym.SymTabIdx = i; } - SymTab.Size = SymTabBuf.size(); + // One greater than the symbol table index of the last local symbol + SymTab.Info = FirstNonLocalSymbol; + SymTab.Size = SymTab.size(); } /// EmitSectionTableStringTable - This method adds and emits a section for the @@ -458,36 +1001,29 @@ void ELFWriter::EmitSymbolTable() { /// section names. void ELFWriter::EmitSectionTableStringTable() { // First step: add the section for the string table to the list of sections: - ELFSection &SHStrTab = getSection(".shstrtab", ELFSection::SHT_STRTAB, 0); + ELFSection &SHStrTab = getSectionHeaderStringTableSection(); // Now that we know which section number is the .shstrtab section, update the // e_shstrndx entry in the ELF header. - OutputBuffer FHOut(FileHeader, is64Bit, isLittleEndian); - FHOut.fixhalf(SHStrTab.SectionIdx, ELFHeader_e_shstrndx_Offset); + ElfHdr.fixWord16(SHStrTab.SectionIdx, ELFHdr_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 (std::list::iterator I = SectionList.begin(), - E = SectionList.end(); I != E; ++I) { + for (ELFSectionIter I=SectionList.begin(), E=SectionList.end(); I != E; ++I) { + ELFSection &S = *(*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. - I->NameIdx = Index; - - // Add the name to the output buffer, including the null terminator. - Buf.insert(Buf.end(), I->Name.begin(), I->Name.end()); - - // Add a null terminator. - Buf.push_back(0); + S.NameIdx = Index; + SHStrTab.emitString(S.getName()); // Keep track of the number of bytes emitted to this section. - Index += I->Name.size()+1; + Index += S.getName().size()+1; } // Set the size of .shstrtab now that we know what it is. - assert(Index == Buf.size()); + assert(Index == SHStrTab.size()); SHStrTab.Size = Index; } @@ -496,64 +1032,67 @@ void ELFWriter::EmitSectionTableStringTable() { /// SectionTable. void ELFWriter::OutputSectionsAndSectionTable() { // Pass #1: Compute the file offset for each section. - size_t FileOff = FileHeader.size(); // File header first. + size_t FileOff = ElfHdr.size(); // File header first. + + // Adjust alignment of all section if needed, skip the null section. + for (unsigned i=1, e=SectionList.size(); i < e; ++i) { + ELFSection &ES = *SectionList[i]; + if (!ES.size()) { + ES.Offset = FileOff; + continue; + } + + // Update Section size + if (!ES.Size) + ES.Size = ES.size(); - // 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(); + if (ES.Align) + FileOff = (FileOff+ES.Align-1) & ~(ES.Align-1); + + ES.Offset = FileOff; + FileOff += ES.Size; } // Align Section Header. - unsigned TableAlign = is64Bit ? 8 : 4; + unsigned TableAlign = TEW->getPrefELFAlignment(); 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); + ElfHdr.fixWord16(NumSections, ELFHdr_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); + ElfHdr.fixWord(FileOff, ELFHdr_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); + O.write((char *)&ElfHdr.getData()[0], ElfHdr.size()); + FileOff = ElfHdr.size(); - DataBuffer Table; - OutputBuffer TableOut(Table, is64Bit, isLittleEndian); + // Section Header Table blob + BinaryObject SHdrTable(isLittleEndian, is64Bit); - // Emit all of the section data and build the section table itself. - while (!SectionList.empty()) { - const ELFSection &S = *SectionList.begin(); + // Emit all of sections to the file and build the section header table. + for (ELFSectionIter I=SectionList.begin(), E=SectionList.end(); I != E; ++I) { + ELFSection &S = *(*I); + DEBUG(dbgs() << "SectionIdx: " << S.SectionIdx << ", Name: " << S.getName() + << ", Size: " << S.Size << ", Offset: " << S.Offset + << ", SectionData Size: " << S.size() << "\n"); // 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 << (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(); + if (S.size()) { + if (S.Align) { + for (size_t NewFileOff = (FileOff+S.Align-1) & ~(S.Align-1); + FileOff != NewFileOff; ++FileOff) + O << (char)0xAB; + } + O.write((char *)&S.getData()[0], S.Size); + FileOff += S.Size; + } + + EmitSectionHeader(SHdrTable, S); } // Align output for the section table. @@ -562,5 +1101,5 @@ void ELFWriter::OutputSectionsAndSectionTable() { O << (char)0xAB; // Emit the section table itself. - O.write((char*)&Table[0], Table.size()); + O.write((char *)&SHdrTable.getData()[0], SHdrTable.size()); }