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Diffstat (limited to 'lib/CodeGen/ELFWriter.cpp')
| -rw-r--r-- | lib/CodeGen/ELFWriter.cpp | 1105 |
1 files changed, 0 insertions, 1105 deletions
diff --git a/lib/CodeGen/ELFWriter.cpp b/lib/CodeGen/ELFWriter.cpp deleted file mode 100644 index f2c218565854..000000000000 --- a/lib/CodeGen/ELFWriter.cpp +++ /dev/null @@ -1,1105 +0,0 @@ -//===-- ELFWriter.cpp - Target-independent ELF Writer code ----------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements the target-independent ELF writer. This file writes out -// the ELF file in the following order: -// -// #1. ELF Header -// #2. '.text' section -// #3. '.data' section -// #4. '.bss' section (conceptual position in file) -// ... -// #X. '.shstrtab' section -// #Y. Section Table -// -// The entries in the section table are laid out as: -// #0. Null entry [required] -// #1. ".text" entry - the program code -// #2. ".data" entry - global variables with initializers. [ if needed ] -// #3. ".bss" entry - global variables without initializers. [ if needed ] -// ... -// #N. ".shstrtab" entry - String table for the section names. -// -//===----------------------------------------------------------------------===// - -#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/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/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/Target/TargetRegisterInfo.h" -#include "llvm/Support/Debug.h" -#include "llvm/Support/ErrorHandling.h" -#include "llvm/Support/raw_ostream.h" -#include "llvm/ADT/SmallString.h" -using namespace llvm; - -char ELFWriter::ID = 0; - -//===----------------------------------------------------------------------===// -// ELFWriter Implementation -//===----------------------------------------------------------------------===// - -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) { - - MAI = TM.getMCAsmInfo(); - TEW = TM.getELFWriterInfo(); - - // Create the object code emitter object for this target. - ElfCE = new ELFCodeEmitter(*this); - - // Initial number of sections - NumSections = 0; -} - -ELFWriter::~ELFWriter() { - delete ElfCE; - delete &OutContext; - - while(!SymbolList.empty()) { - delete SymbolList.back(); - SymbolList.pop_back(); - } - - while(!PrivateSyms.empty()) { - delete PrivateSyms.back(); - PrivateSyms.pop_back(); - } - - while(!SectionList.empty()) { - delete SectionList.back(); - SectionList.pop_back(); - } - - // 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<TargetLoweringObjectFile&>(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; - } - } - - const MCSectionELF *CPSect = - (const MCSectionELF *)TLOF.getSectionForConstant(Kind); - return getSection(CPSect->getSectionName(), CPSect->getType(), - CPSect->getFlags(), CPE.getAlignment()); -} - -// 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; - - std::string SectionName(".rel"); - if (TEW->hasRelocationAddend()) - SectionName.append("a"); - SectionName.append(S.getName()); - - return getSection(SectionName, SectionType, 0, TEW->getPrefELFAlignment()); -} - -// 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; -} - -// getGlobalELFBinding - Returns the ELF specific binding type -unsigned ELFWriter::getGlobalELFBinding(const GlobalValue *GV) { - if (GV->hasInternalLinkage()) - return ELF::STB_LOCAL; - - if (GV->isWeakForLinker() && !GV->hasCommonLinkage()) - return ELF::STB_WEAK; - - return ELF::STB_GLOBAL; -} - -// getGlobalELFType - Returns the ELF specific type for a global -unsigned ELFWriter::getGlobalELFType(const GlobalValue *GV) { - if (GV->isDeclaration()) - return ELF::STT_NOTYPE; - - if (isa<Function>(GV)) - return ELF::STT_FUNC; - - return ELF::STT_OBJECT; -} - -// 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<Function>(GV)); -} - -// 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; - } -} - -/// 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; -} - - -// 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; - - // 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<GlobalVariable>(GV) && "GV not a global variable!"); - const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV); - - // Handle special llvm globals - if (EmitSpecialLLVMGlobal(GVar)) - return; - - // 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()); - - if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) { - for (unsigned i = 0, e = CVA->getNumOperands(); i != e; ++i) - EmitGlobalConstant(CVA->getOperand(i), GblS); - return; - } else if (isa<ConstantAggregateZero>(CV)) { - GblS.emitZeros(Size); - return; - } else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) { - EmitGlobalConstantStruct(CVS, GblS); - return; - } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(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<ConstantInt>(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<ConstantVector>(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<ConstantExpr>(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<GlobalValue>(Op)) - EmitGlobalDataRelocation(cast<const GlobalValue>(Op), - TD->getTypeAllocSize(Op->getType()), - GblS, Res.second); - else - EmitGlobalConstant(Op, GblS); - - return; - } else if (CV->getType()->getTypeID() == Type::PointerTyID) { - // Fill the data entry with zeros or emit a relocation entry - if (isa<ConstantPointerNull>(CV)) - GblS.emitZeros(Size); - else - EmitGlobalDataRelocation(cast<const GlobalValue>(CV), - Size, GblS); - return; - } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(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<ConstantExpr>(CV)) - return std::make_pair(CV, 0); - - const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV); - switch (CE->getOpcode()) { - case Instruction::BitCast: - return ResolveConstantExpr(CE->getOperand(0)); - - case Instruction::GetElementPtr: { - const Constant *ptrVal = CE->getOperand(0); - SmallVector<Value*, 8> 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<ConstantInt>(Op1) && "Op1 must be a ConstantInt"); - - CstExprResTy Res = ResolveConstantExpr(Op0); - assert(isa<GlobalValue>(Res.first) && "Op0 must be a GlobalValue"); - - const APInt &RHS = cast<ConstantInt>(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 -} - -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<GlobalValue*>(GV), - Offset); - - // 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<ConstantArray>(List); - for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { - if (InitList->getOperand(i)->isNullValue()) - continue; - ConstantStruct *CS = cast<ConstantStruct>(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 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) { - // 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(); - - // Emit the relocation sections. - EmitRelocations(); - - // Emit the sections string table. - EmitSectionTableStringTable(); - - // Dump the sections and section table to the .o file. - OutputSectionsAndSectionTable(); - - return false; -} - -// 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<MachineRelocation> Relos = S.getRelocations(); - for (std::vector<MachineRelocation>::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); - } - } -} - -/// 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); - } -} - -/// 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); - } -} - -/// 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. - StrTab.emitByte(0); - - // Walk on the symbol list and write symbol names into the string table. - unsigned Index = 1; - 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()) { - Sym.NameIdx = 0; - } else { - Sym.NameIdx = Index; - StrTab.emitString(Name); - - // Keep track of the number of bytes emitted to this section. - Index += Name.size()+1; - } - } - 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<ELFSym*> 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 = 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; - } - - // 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 -/// ELF Section Table string table: the string table that holds all of the -/// section names. -void ELFWriter::EmitSectionTableStringTable() { - // First step: add the section for the string table to the list of sections: - ELFSection &SHStrTab = getSectionHeaderStringTableSection(); - - // Now that we know which section number is the .shstrtab section, update the - // e_shstrndx entry in the ELF header. - 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; - - 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. - S.NameIdx = Index; - SHStrTab.emitString(S.getName()); - - // Keep track of the number of bytes emitted to this section. - Index += S.getName().size()+1; - } - - // Set the size of .shstrtab now that we know what it is. - assert(Index == SHStrTab.size()); - SHStrTab.Size = Index; -} - -/// 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 = 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(); - - // Align FileOff to whatever the alignment restrictions of the section are. - if (ES.Align) - FileOff = (FileOff+ES.Align-1) & ~(ES.Align-1); - - ES.Offset = FileOff; - FileOff += ES.Size; - } - - // Align Section Header. - 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. - 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. - 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 *)&ElfHdr.getData()[0], ElfHdr.size()); - FileOff = ElfHdr.size(); - - // Section Header Table blob - BinaryObject SHdrTable(isLittleEndian, is64Bit); - - // 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.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. - for (size_t NewFileOff = (FileOff+TableAlign-1) & ~(TableAlign-1); - FileOff != NewFileOff; ++FileOff) - O << (char)0xAB; - - // Emit the section table itself. - O.write((char *)&SHdrTable.getData()[0], SHdrTable.size()); -} |